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C.A.P.E. ESTUARY MANAGEMENT PROGRAMME
KEURBOOMS/BITOU ESTUARY MANAGEMENT PLAN
VOLUME IVOLUME IVOLUME IVOLUME I
SITUATION ASSESSMENTSITUATION ASSESSMENTSITUATION ASSESSMENTSITUATION ASSESSMENT
Final Report
Produced by:
Enviro-Fish Africa (Pty) Ltd
22 Somerset Street
Grahamstown
6139
Produced for:
C.A.P.E. Estuaries Programme Eden District Municipality
Pvt Bag X29 P.O. Box 12
Rondebosch George
7701 6530
August 2010
C.A.P.E. Estuaries Management Programme; Keurbooms/Bitou Estuary Management Plan: Situation Assessment
Enviro-Fish Africa (Pty) Ltd.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY iii
LIST OF TABLES, FIGURES & PLATES xxviii
LIST OF ACRONYMS xxx
CHAPTER 1 - INTRODUCTION 1
1.1 Introduction 1
1.2 Terms of reference 1
1.3 Project team 2
CHAPTER 2 - BIO-PHYSICAL DESCRIPTION 3
2.1 Introduction 3
2.2 The extent of the estuarine area 6
2.3 Physical structures 7
2.4 Physical properties 8
2.5 Floods 16
CHAPTER 3 - BIOLOGICAL DESCRIPTION 19
3.1 Flora 19
3.2 Fauna 23
CHAPTER 4 – LEGISLATION AND PLANNING & DEVELOPMENT
STRATEGIES 28
4.1 International obligations 28
4.2 National legislation and policy 28
4.3 Local (Municipal) legislation 33
4.4 Existing management plans, development strategies, policies
and conservation initiatives 34
CHAPTER 5 – RECREATIONAL USE 46
5.1 Exploitation of living resources 46
5.2 Tourism and non-consumptive use 49
CHAPTER 6 - WATER QUANTITY AND QUALITY 51
6.1 Introduction 51
6.2 Management of the catchment 51
6.3 Catchment description 51
6.4 Ecological status 54
6.5 Wetlands 56
6.6 Water quantity 57
6.7 Water quality 58
6.8 Ecological water requirements 59
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6.9 Socio-cultural importance 67
6.10 Pressures/Risk/Threats 67
CHAPTER 7 – CLASSIFICATION, ECONOMIC VALUE,
PROTECTION AND REHABILITATION 68
7.1 Classification 68
7.2 Economic value 69
7.3 Protected area strategy and potential 69
7.4 Restoration/rehabilitation 74
7.5 Climate change 74
CHAPTER 8 - THE WAY FORWARD: OBJECTIVE II 75
8.1 Local estuary management forum 75
8.2 The estuarine management plan 75
8.3 The stakeholder workshop 76
8.4 Issues raised by stakeholders 79
CHAPTER 9 - REFERENCES 81
APPENDIX 1 85
APPENDIX 2 87
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EXECUTIVE SUMMARY
CHAPTER 1 - INTRODUCTION Estuarine ecosystems are not isolated systems. They form an interface between marine
and freshwater systems and are part of regional, national and global ecosystems either
directly via water flows or indirectly through the movement of fauna. In addition to the
biota that these estuaries support, they provide a range of goods and services (uses) to the
inhabitants of the various regions. The interaction between estuaries and users creates a
delicate balance, the sustainability of which needs to be addressed by some form of
management plan.
The urgent need for Estuary Management Plans (EMPs) became apparent during the
development of the Integrated Coastal Management Act (Act 24 of 2008; ICMA), and are
designed to help align and coordinate estuaries management at a local level. Enviro-Fish
Africa (Pty) Ltd. has been contracted by the C.A.P.E. Estuaries Programme to address the
development of an EMP for the Keurbooms and Bitou Estuaries. This report fulfills the
requirements of Objective 1, namely a Situation Assessment.
CHAPTER 2 – PHYSICAL DESCRIPTION
INTRODUCTION
The Keurbooms and Bitou estuaries (collectively referred to as the Keurbooms) are
located close to Plettenberg Bay and both feed into what is known as the Keurbooms
Lagoon, which is separated from the sea by a prominent berm, prior to it flowing out to
sea. The confluence of the Bitou and Keurbooms estuaries is approximately 3.5 km from
the mouth. The Bitou River is 23 km long, with its source at Buffelsnek, and is tidal for
7.2 km from the confluence to the causeway at Wittedrift. The Keurbooms River is
approximately 85 km long, with its source at Spitskop in the Outeniqua Mountains, and is
tidal for approximately 8.5 km from the confluence. The combined catchment has been
estimated at anywhere between 1085 and 1188 km2.
The Keurbooms is a warm-temperate, permanently open, medium-large, Type F barred
system (supratidal barrier), whose ichthyofauna, water quality and aesthetics are rated as
good, good and moderate respectively. The Bitou Estuary above the N2 is characterized
by an extensive floodplain and wetland complex, while the Keurbooms Estuary above the
N2 has no floodplain and is characterized by steep gorges. Extensive intertidal areas,
dominated by sandbanks, mudbanks, saltmarsh and freshwater creeks, characterize both
estuaries below the N2 and the lagoon area. There are two statutory conservation areas
administered by CapeNature, namely the Keurbooms River Nature Reserve and the
Keurbooms River Seagull Breeding Colony. In addition to this, there are significant areas
of private land that are managed for conservation purposes and the Eden to Addo
Corridor Initiative is looking to protect plant and animal habitats through establishing
biodiversity corridors on privately owned land between formally protected areas. Land
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use in the Keurbooms catchment comprises approximately 15% commercial agriculture
and 85% natural shrubland, bushland and forest. Very little (<1%) is degraded or
developed. The upper Bitou catchment comprises mostly State owned indigenous forests;
with the rest of the catchment comprising privately owned land with indigenous forest
and cultivated lands. The lower Bitou catchment comprises mostly farmland, urban
settlements and a sewage treatement works at the head of the Gansevallei.
THE EXTENT OF THE ESTUARINE AREA
The Keurbooms Estuary extends approximately 1.5 km upstream from Whiskey Creek
and the Bitou Estuary extends as far as the causeway over the Wittedrift road. These are
the generally accepted limits, but the exact upper limit of each estuary at any one time
will vary depending on tidal flows in relation to the volume of freshwater entering from
upstream. The seaward extent of the Keurbooms Lagoon is located at the mouth, which
varies according to the location where floods breach the barrier and the subsequent rate of
migration in a SW direction. With regards the terrestrial boundaries, there are several
options commonly used to define the area, namely:
• Floodlines – either the 1:50 or 1:100 year floodlines. These provide a good indication
of the historical extent of floods and therefore areas that pose a risk for developments
and infrastructure.
• 5 m contour – this may be useful in the context of the projected sea level rise and
increase in the severity of floods and storm events due to climate change.
• Coastal protection zone – this zone is defined as a 100 or 1 000 m buffer zone
measured inland from the high water mark and also makes provision for any land
located within the 1:50 year floodline. Essentially, the 100 m zone is defined for areas
zoned as urban and the 1 000 m zone is defined for rural (agricultural) areas. It must
be made clear that these zones are designed to restrict certain activities that may
interfere with the estuary and its sensitive riparian areas, but it does NOT mean that
no activities may take place. Activities that should be restricted, or at least assessed
prior to authorization are those listed in the National Water Act (NWA) that require a
license (e.g. water use), the EIA Regulations and those affecting sustainable
development and sensitive ecosystems These zones do NOT indicate that landowners
may not operate within their boundary, i.e. they do not lose this land, but they must
adhere to sound environmental principles when conducting any activities.
• EIA regulations – although not used to specifically define the estuary area, the 100 m
buffer zone also provides an indication of the area in which listed activities are
regulated relative to the high water mark in accordance with the EIA Regulations.
PHYSICAL STRUCTURES
The road bridge over the Bitou Estuary at Wittedrift and the old causeway immediately
downstream act as obstructions to water flow and essentially form the upper limit of tidal
exchange in the estuary. The existing N2 bridge and embankment obstructs more than
45% of the river width of the Bitou Estuary. A low causeway is present across the Bitou
Estuary approximately 1.5 km upstream of the N2 Bridge. This causes some constriction
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to tidal flows especially at low tides. The N2 bridge over the Keurbooms Estuary does
not appear to affect the orientation of the channel, but may contribute to increased
sediment deposition immediately downstream. There are three picnic sites, administered
by CapeNature, one on the eastern bank and two on the western bank of the Keurbooms
Estuary above the N2 bridge. There is one slipway above the N2 bridge on the
Keurbooms Estuary and seven below the N2 bridge. There are no slipways upstream of
the N2 bridge on the Bitou Estuary and no jetties upstream of the N2 on either the Bitou
or Keurbooms Estuaries. There are two jetties and one boathouse/jetty on the western
side of the Bitou channel below the N2 and a slipway on the eastern side. A single long
jetty extends from Stanley’s Island and a further 4 jetties exist on the eastern side of the
eastern Keurbooms channel below the N2. A small-boat harbour, comprising mooring
facilities for over 100 boats and a slipway are located on the western side below the N2 at
the Plettenberg Bay Angling Club.
PHYSICAL PROPERTIES
DEPTH
The lower reaches of the Keurbooms Estuary is approximately 3 m below MSL and
becomes shallower towards the middle reaches. Upstream of the N2 bridge, average
depth is considerably greater with some sections measuring in excess of 20 m below
MSL. The estuary becomes very shallow at and above Whisky Creek. The depth of the
Bitou Estuary varies between 2.7 m below and 0.7 m above MSL, with the deeper
sections being located upstream of the N2 bridge. Tidal variation inside the mouth is 1.35
m and decreases to 0.95 m and 0.85 m at the N2 bridges on the Keurbooms and Bitou
Estuaries respectively. Although tidal variation occurs throughout the estuarine basin on
the spring tide, active tidal exchange in which the entire water column is flushed occurs
primarily in the lower reaches below the N2 bridges.
There is no record of mouth closure occurring at the Keurbooms Estuary, but the mouth
sometimes becomes very shallow. It is also a matter of concern that the estuary becomes
very shallow at places between the mouth and the N2 bridges, which indirectly could
contribute to mouth closure occurring in the future. A major long-term impact of water
abstraction from the Keurbooms and Bitou estuaries can be mouth closure.
SEDIMENT PROCESSES AND CHARACTERISTICS
The surf zone is the main sediment source for both estuaries, and river floods are
important to temporarily scour open inlets and remove tidal-accumulated sediment from
the lower reaches. The tidal prism of the Keurbooms Estuary is in the order of 1.8 x 106
m3 and the mean spring tidal range in the bay is about 1.6 m. The neap tidal range is very
small in the estuary due to the large accumulation of sand in the tidal inlet. Due to the
constriction of the tidal inlet, the estuary is flood tide dominated. Annually about 1.5 x
104 m
3 of marine sand enters the back-barrier Keurbooms lagoon and the scour by tidal
flows removes enough of the wave deposited sand to maintain the inlet channel and allow
restricted tidal exchange.
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The inlet migrates southwestward by erosion of the southern inlet margin and the growth
of the northern margin. The primary reason for the southwesterly migration of the mouth
is the scouring of the southwest spit that occurs on ebb tides as the flow alters direction to
accommodate the 45º angle of the mouth to the coastline. Several evenly spaced
washover channels are present on the sand barrier and washover sand is an important
local source of marine sand in the estuary. Severe flooding occurs in both systems, with
the most recent in 2007 being the most devastating in living memory. Apart from the
major damage to infrastructure located on the floodplain and scouring of sediment along
the course of the estuaries, floods have a major impact on the mouth in the following
ways:
• The estuary mouth is deepened and widened.
• The normally complex estuary mouth is temporarily straitened.
• Floods are playing a major role in the long-term sediment dynamics upstream of the
estuary mouth. Ongoing inland movement of marine sediments takes place during
periods when only minor floods occur, causing a gradual shallowing of the estuary. In
the long term this ongoing sedimentation is counter balanced by flushing of sediments
during major floods.
TEMPERATURE
There is little evidence of vertical temperature stratification, with surface and bottom
temperatures measuring between 12 and 22.9 ºC. This lower limit is likely to be seen
during coastal upwelling events when cold marine water pushes into the system during
the flood tide. The normal temperature regime, which shows a strong seasonal pattern, is
between 20 and 25oC in summer and 15 and 20
oC in winter. A horizontal gradient exists,
with temperatures increasing upstream. On average the Bitou Estuary is warmer than the
Keurbooms Estuary.
SALINITY
Salinities range from 13 to 35 ppt, with highest salinities in the mouth region. Surface
salinity ranges between 35 and 15.3 ppt and bottom salinities between 35 and 22.6 ppt.
This type of stratification is more evident above the N2 bridges and more pronounced in
deeper areas and over the neap tide cycle; salinity decreases as one moves upstream. On
average, the Bitou Estuary is more saline than the Keurbooms Estuary. Salinity levels
will generally decrease over winter due to increased freshwater runoff. Tidal exchange
occurs throughout the systems, but the entire water column is only flushed each spring
tidal cycle below the N2 bridges.
pH
The pH in the systems ranges from 6 to 8.6 with values decreasing upstream in the
Keurbooms Estuary in lower salinities but showing an increase upstream in the Bitou
Estuary. Riverine water in both systems is slightly acidic due to the leaching of humic
acid.
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DISSOLVED OXYGEN
Dissolved oxygen values in both estuaries may vary between 0 and 11.8 mg/l with the
lowest values being associated with the deeper sections. These low concentrations may
persist in times of prolonged reduced freshwater flow, as inflow is responsible for
flushing these deeper sections.
TURBIDITY
Turbidity is very low, with Secchi disc readings averaging between 1.4 and 1.7 m and
only reduced to < 1 m at times of flooding.
POLLUTION
Sewage
Treated sewage from the Bitou treatment facility (see Figure 2.2) is discharged in the
Bitou estuary via the Gansvlei and Rietvlei wetland systems at the head of Gansevalei,
increasing the flux of nutrients into the system. Most of the treated sewage is currently
used to irrigate existing golf courses and polo fields and it is expected that the demand for
treated sewage will grow. There is, however a risk of untreated sewerage entering the
system either due to failed infrastructure or floods scouring through the treatment works.
Industrial
No industrial activities take place in the catchment of the Keurbooms or Bitou Rivers.
Metals
Concentrations of elements in water samples are considered average for similar
southeastern Cape rivers, with the exception of lead and cadmium, which are elevated.
No source could be identified and it is thought they may be of geochemical origin. Metals
in surface sediments are considered average, but on average were slightly elevated in the
Bitou when compared to the Keurbooms, possibly due to mineralisation in the catchment.
Concentrations were elevated in the vicinity of the Plettenberg Bay Angling Club marina
on the Keurbooms, most likely as a result of spills and human activity. The southwestern
arm of the lagoon close to Poortjies and Plettenberg Bay exhibited elevated levels due to
contaminated urban runoff.
FLOODS
FRESHWATER FLOODS
The Keurbooms and Bitou systems are prone to episodic flooding that has catastrophic
consequences for landowners and infrastructure and also poses a risk to human safety.
Floodwaters cause extensive erosion, particularly in the lower reaches where land has
been cleared to make way for residential developments and resorts. The removal of
riparian vegetation weakens the banks’ stability causing it to be undercut and ultimately
collapse into the estuary. The effects of these floods have been exacerbated in recent
times by the accumulation of debris in the catchment, mostly from forestry and alien
clearing projects. The greatest damage occurs in the Keurbooms system below the N2
bridge, as this is where the most development has occurred and where vegetation has
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been cleared. However, most structures adjacent to the estuary are affected to some
extent. The Bitou floodplain suffers less direct structural damage to infrastructure and
land, but dwellings are still prone to flooding.
MARINE (STORM) FLOODS
Flooding from the seaward side during extreme storm events can also cause widespread
damage to property, infrastructure and the banks of the estuary that have been
destabilized by developments.
RECOMMENDATIONS
The following recommendations can be considered:
• No new developments within the risk area – this could be the 1:100 year floodline or
below the 5 m contour.
• Planting of vegetation along the estuary banks where it has been cleared.
• Clearing of debris from the catchment by forestry and those responsible for alien
clearing.
• Bank stabilization to repair existing damage and to minimize impacts from future
events. Attempts to stabilize the banks in the lower reaches of the Keurbooms have
met with varying levels of success and the EMP will attempt to establish a protocol
for best practice based on existing technologies and past successes. In addition, the
authorization process needs to be revisited to account for landowners needing to carry
out repairs after each event without having to undertake the EIA process each time.
CHAPTER 3 – BIOLOGICAL DESCRIPTION
FLORA
MICROALGAE
An increase in freshwater input causes a decrease in mean salinity, an increase in the
horizontal gradient and an increase in nitrate and chlorophyll-a concentrations. This
indicates that freshwater inflow stimulates microalgal growth and therefore primary
productivity. Benthic microalgal biomass ranges from 106 – 191 mg/m2 for intertidal
sites and from 257 to 640 mg/m2 for subtidal sites. Intertidal benthic microalgal biomass
has been recorded between 9.53 ± 0.78 µg/g1. This value is low when compared to other
permanently open estuaries sampled and is related to the sandy nature of the estuary and
low sediment organic content compared.
MACROALGAE
Submerged macrophytes
Zostera capensis is the dominant submerged macrophyte in the Keurbooms Estuary and
Ruppia cirrhosa is the dominant form in the Bitou Estuary. Although Ruppia has a wide
salinity tolerance range (0-75 ppt), it does not survive in the lower reaches since it has
relatively weak stems that break in the presence of strong currents. Very little Z. capensis
was found in the Bitou Estuary above the N2 bridge because of reduced tidal action
caused by physical obstructions.
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Emergent macrophytes
In the Keurbooms Estuary, reeds and sedges are limited to the supratidal marshes and
areas of freshwater inflow. The Bitou Estuary is characterized by dense monospecific
stands of Schoenoplectus scirpoides and Phragmites australis within the channel because
of the low flow and restricted tidal action.
Intertidal saltmarsh
The dominant intertidal salt marsh species in the Keurbooms are Spartina maritima,
Sarcocornia perennis and Sarcocornia decumbens. Salt marshes are not extensive in the
Keurbooms Estuary due to the geomorphology of the system. The Bitou Estuary has a
wide floodplain connected to the estuary by numerous tidal creeks. The largest areas of
salt marsh occur on these floodplains.
Supratidal saltmarsh
The elevated areas of the floodplains are covered with supratidal salt marsh vegetation,
mainly Sarcocornia pillansii. The largest supratidal salt marshes are found on the
floodplain of the Bitou Estuary. Mats of grasses such as brakgras and seaside quick
dominate large sections of the disturbed upper marsh in both the Bitou and Keurbooms
estuaries. The fringes of the floodplains are occupied by reeds, rushes and sedges, which
are an indication of freshwater inflow.
Terrestrial plants
The terrestrial vegetation in the middle and lower reaches can be grouped into five types,
namely primary dune scrub, secondary dune scrub, hind dune scrub, fynbos and aliens.
The upper reaches are characterized by dense indigenous forest interspersed with alien
trees. Alien tree species are invading the floodplain areas of the Bitou and Keurbooms
Estuaries, and infestation is also a problem within the entire catchment/riverine area.
THE BITOU FLOODPLAIN/WETLAND COMPLEX The Bitou wetlands located between the N2 road/bridge and the Bosfontein River are one
of the last undeveloped floodplains along the Western Cape coast and comprise a series
of typical open freshwater marsh systems, supra- and inter-tidal saltmarsh, river channels
and the Bitou Estuary channel itself. Floods are episodic, usually occurring in
spring/early summer and are vital for maintaining ecosystem functioning in combination
with the twice-daily tidal cycles. The Bitou wetlands are the most valuable ecological
resource of the entire catchment, and are currently under severe threat of development on
its perimeter. The wetland corridor provides a link between the SANParks Forest Reserve
and the Keurbooms Nature Reserve and potentially allows for the movement of species
between protected areas.
Floodplain saltmarsh areas are dominated by Sarcocornia perennis while riparian areas
comprise mostly reeds and sedge. Upstream of the causeway, the riparian vegetation
comprises indigenous milkwoods and some yellowwoods. The floodplain in the upper
reaches also comprises scattered concentrations of rush. The terrestrial portion of the
Bitou Valley comprises fynbos associated species, Valley Thicket and Knysna
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Afromontane Forest. Numerous shallow open pans are scattered on the floodplain and are
considered an important habitat for birds.
The Rietvlei wetland system is a complex of seasonal and permanent vegetation
including S. littoralis, Bulboschoenus maritimus, Typhus sp. and aquatic grasses.
Baillon’s crake, which is a Red Data species, is known to breed here and other rare birds
such as the redchested flufftail, African rail, black crake, purple gallinule and purple
heron are common residents. Areas characterized by temporary pools and short grasses
are dominated by small waders, ducks, spoonbills and ibis.
Large areas of the floodplain are used for grazing cattle, but this is not intensive, and
vegetation cover and riparian cover are maintained so that erosion and bank
destabilization (also from trampling) is not a concern. Cows access the water to drink
when it is not too saline. There are several access roads through the floodplain on private
property and although it is unknown whether these have an adverse affect, it is unlikely
as they do not block drainage channels and still allow free movement of water.
The Gansvlei/Diep River/Rietvlei system of rivers and wetlands serve to filter and further
purify the treated effluent from the Bitou Sewerage Works located at the head of
Gansevalei. The maintenance of these wetlands as a buffer is important if water quality
entering the Bitou Estuary is to be maintained at an acceptable level.
The land on the northern side of the Bitou Estuary is currently still being used for grazing
and does not appear to have been severely degraded. Meetings with current landowners
revealed that they feel they look after the area already and do not need a conservancy to
facilitate a management function they already fulfill. A recommendation may be to fence
off sensitive areas to prevent damage to vegetation by grazing and trampling, but this will
need to be done in cooperation with the private landowners. In addition, the Eden to
Addo initiative to establish the Bitou Corridor linking the SANParks and Keurbooms
protected areas needs to be considered in cooperation with landowners.
FAUNA
Zooplankton
Zooplankton displays high species richness in the Keurbooms Estuary, with 39 species
being recorded and a dry biomass of between 2.9 to 108 mg/m3. Pseudodiaptomus hessei
is the dominant copepod and is particularly abundant in lower salinity waters above the
N2 bridge in the Keurbooms.
Benthic invertebrates
The largest proportion (42 taxa) of the invertebrate fauna is either benthic or associated
with the aquatic vegetation. The benthic fauna is well developed from the lower reaches
to the middle reaches, with sandprawn, bloodworm, pencilbait and mudprawn being the
dominant forms. Mudprawn and sandprawn together contributed more than 50% (26
tonnes) of the standing stock of benthic organisms in the Keurbooms Estuary. The sand
mussel and the echinoids Echinodiscus bisperforatus (pansy shell) and Echinocardium
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sp. also burrow the sand in the area proximal to the mouth. The largest and most closely
spaced mudprawn population occurs in the Bitou Estuary, where muddier sediments are
present. Macro-invertebrates such as Nassarius, Natica and Diogenes are common on the
mid and distal flat areas while the mud crab is common amongst saltmarsh vegetation and
Zostera beds. An abundance of crabs, either Sesarme castenata or Cleistostoma
edwardsii are present amongst the mud and creek vegetation of Gansvlei.
An important component of the soft sediment community is the pansy shell. Of the three
main populations of pansy shell in South Africa, two are within Plettenberg Bay. One of
these is located along Keurboomstrand and in the lagoon in the vicinity of the mouth near
the caravan park. The limited distribution and high souvenir value have resulted in the
species being classified as endangered in South Africa, and protected by the Sea Fisheries
Act.
Amphibians and reptiles
Fourteen amphibian species, twenty-seven snake species, three species of tortoise and
one terrapin species are likely to be associated with the Keurbooms and Bitou systems.
Freshwater fish
The Keurbooms redfin is an endangered species found in the Kransbos, Diep and
Langbos rivers of the catchment and has been identified as requiring special conservation
attention. In addition, the following indigenous species are known to occur; forest redfin,
Cape galaxias, Cape kurper and longfin eel. Alien species include rainbow trout, brown
trout and large-mouth bass. Two marine-migrant species, namely Cape moony and
freshwater mullet have been found in the riverine region above the estuary.
Marine and estuarine fish
A total of 29 species of fish have been recorded in the Bitou and Keurbooms Estuaries,
with the Mugilidae (5 species), Sparidae (4 species) and Gobiidae (4 species) dominating
the catch. The Cape stumpnose is numerically dominant followed by juvenile mullet.
Dusky kob dominates the community in terms of biomass followed by the mullet Liza
richardsonii. The fish fauna is dominated by marine-migrant species (utilize estuaries but
spawn at sea), with a large juvenile component mostly occurring below the N2 bridges,
reflecting the importance of these systems as a nursery area. In addition to dusky kob,
both systems are home to other important and over-exploited linefish species such as
white steenbras, spotted grunter and leervis. The Knysna seahorse is known to occur and
is listed as an Endangered species on the IUCN Red List due to its fragmented
distribution, small area of occupancy, the vulnerability of its habitat and susceptibility to
high mortality due to freshwater flooding. There is an hypothesis that the Knysna
population may be the source of new colonists for the Keurbooms after flood events and
that the system is merely a temporary habitat for the species at times when conditions are
favorable. Research is urgently required to determine whether the Keurbooms population
is permanent.
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Birds
A total of 64 species, totaling 31 051 individuals have been recorded over the 13 year
period by the Coordinated Waterbird Counts (CWAC) programme. The kelp gull is by far
the most dominant species, followed by the swift (great crested) tern, grey plover, reed
cormorant, curlew sandpiper, sacred ibis and common whimbrel. Two pursuit-swimming
piscivores, namely the white-breasted cormorant and the Cape cormorant, which are
capable of feeding on up to 16% of their body weight daily, also occur in moderate
numbers. A total of 503 of the endangered African black oystercatcher have been
counted.
The most birds were counted in January 1997, with 2 072 individuals being recorded,
followed by January 1996 (1 695), February 2002 (1 569), January 2005 (1 519) and July
1996 (1 365). Counts over summer months always exceed those in winter of the same
year due to the influx of summer migrants. In summer the avifauna is dominated by
migratory waders, gulls and terns. The remaining avifauna includes a variety of wading
birds (particularly Sacred Ibis and Reed Cormorant), resident waders, cormorants and
small numbers of waterfowl. In winter, numbers are dominated by terns, gulls and
wading birds (particularly Reed Cormorant and Sacred Ibis. About 12% of migratory
waders remain in winter.
A report based on CWAC counts between 1992 and 1997 stated that bird species
numbers and total counts for the Bitou Estuary had been on the decrease and this was
attributed to pollution from effluent, pesticides and fertilizers, damage to habitat by
livestock, siltation of the estuary, reed encroachment and residential development. The
lower Bitou River includes excellent marsh habitat for rails and other secretive birds, and
redchested flufftail and Baillon's crake may breed in this area. Moorhen counts peak in
winter although recorded numbers are decreasing; winter Dabchick counts are also
decreasing. The area is important for foraging and roosting shorebirds, waterfowl and
egrets. The Bitou wetlands system is considered vital from a bird (breeding and
biodiversity) point of view and is need of protection.
The Keurbooms River Seagull Breeding Colony located along the barrier in the lagoon
area has the largest breeding colony of kelp gulls in the region, with approximately 1450
breeding pairs recorded in 2003. In addition, the African black oystercatcher and several
tern species are also thought to breed and roost within the sanctuary.
Mammals
Common mammals that may be spotted within the Keurbooms Nature Reserve and in
close association with the estuaries include the bushpig, dassie, caracal, genet, baboon,
vervet monkey, blue duiker, bushbuck, grysbok, leopard, mongoose and the Cape
clawless otter.
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CHAPTER 4 – LEGISLATION AND PLANNING &
DEVELOPMENT STRATEGIES
The purpose of this section is to review all forms of legislation that may have an impact
on the management of the Keurbooms and Bitou Estuaries. This review incorporates
international agreements and strategies as well as all forms of national, regional and local
legislation as well as municipal planning and development strategies, and other
conservation or development framework initiatives. The details will not be reproduced in
the executive summary and can be viewed in Chapter 4 of the main Report.
CHAPTER 5 – RECREATIONAL USE
EXPLOITATION OF LIVING RESOURCES
KING ET AL.
A survey revealed the following about the fishery on the Keurbooms and Bitou Estuaries.
• The fishery is male dominated and comprised 68% whites, 38% coloured and 1%
black.
• 48% of the participants live within 30km of the estuaries.
• Recreational shore-based anglers comprised 46% and boat-based anglers 52%; only
2% were classified as subsistence.
• 86% of anglers were not affiliated to any club.
• Subsistence anglers fish for substantially longer periods per outing than shore- or
boat-based anglers. 42% of anglers undertake night-fishing outings as well.
• Effort is higher on weekends and public holidays for recreational anglers but no
difference was noted for subsistence users.
• Effort was highest below the N2 road bridges for all sectors, with the confluence
region being a key focal point.
• Catch per unit effort (Cpue) was highest for boat-based anglers (0.07
fish/angler/hour) followed by subsistence anglers (0.03) and shore-based anglers
(0.02). Overall average cpue was 0.04 fish/angler/hour and total estimated harvest for
the survey period was 19 452 fish (6 573 kg).
• Only 32% of anglers catch at least one fish per outing and only 4% ever attain or
exceed the bag limit for a species.
• Fourteen species were recorded in catches, of which Cape stumpnose was
numerically dominant followed by spotted grunter and white steenbras. Spotted
grunter dominated the catch by weight.
• The majority of fish caught were under the minimum legal size.
• 59% of anglers use bait collected exclusively from the estuaries; 13% use bait
collected and bought from retailers; 21% use bait exclusively bought from retailers;
4% used bait bought illegally from subsistence collectors and 3% used artificials.
• Most commonly used bait includes sandprawn, pilchard, mudprawn and pencil bait.
The estimated harvest for sand and mudprawns over the survey period was 199 891
and 185 742 respectively.
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• Angler perceptions were that abundance and mean size of bait organisms has
declined, with 30% attributing this to over exploitation.
• Knowledge of bait and fish regulations was poor.
• Compliance monitoring effort appears to be low, with 72% of anglers never having
had their catches inspected. The frequency of inspection for 34% of those who have
been monitored is less than once in every 50 outings.
• 74% of anglers thought catches had decreased over time (catch rate and average size)
with A. japonicus, P. commersonnii and L. lithognathus being the most noteworthy.
• The high percentage of undersize fish kept by anglers was viewed as a major concern,
and an increase in compliance monitoring efforts combined with an awareness raising
campaign is strongly motivated.
ANECDOTAL INFORMATION
• The fishery is diverse, comprising shore and boat-based anglers using a variety of
gear types.
• Up to 30 power driven boats may be active on the estuary per day during the year, but
during holiday season this may increase to between 300 and 400.
• There are between 30 and 40 rowing boats used by fishermen mainly from New
Horizons with effort concentrated in the lagoon area.
• It is estimated that in excess of 150 and 100 anglers from New Horizons and
Wittedrift respectively fish in the two estuaries and lagoon. Effort is divided between
day and night and weekends (dependant on employment) and between the estuaries
and the sea depending on where fish are being caught. Sandprawn, mudprawn and
pilchards (bought) are the dominant bait items.
• Most effort is during daylight hours and below the N2 bridges.
• Many anglers admit to keeping undersize fish as this is a primary food source.
• More dusky kob is being caught than previously due to use of artificials, particularly
in upper reaches above Whisky Creek.
• Juvenile leervis are present in catches all year, with larger specimens in
February/March. Elf are present between November and April.
• Predominantly juvenile white steenbras are caught in the estuary.
• There is a consensus that fishing has improved since the 2007 floods and that this was
good for the system.
• Illegal bait collecting methods (digging) is not prevalent, but illegal selling does take
place.
• A charter operation takes clients fishing and promotes a catch-and-release ethic.
• The availability and proposed price increase of recreational licenses was viewed as
problematic and in need of attention.
• Education and awareness programmes are required to inform users about regulations
and the importance of the estuaries in general.
• Conflict between user groups is not considered to be a major concern.
• No-take sanctuary zones were recognized as important but site selection needs to be
based on sound scientific data.
• No fishing competitions take place on the estuary and stakeholders felt that this
should not change.
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LICENSED SUBSISTENCE FISHERS
There are 65 subsistence exemptions (permits) that have been granted to fishers in The
Craggs for the year 2010. The permit does allow for the sale of certain fish species but
does not allow for the sale of bait organisms. For the most part these fishers fish in the
marine environment. According to MCM there are no subsistence permits granted to any
fishers residing in the communities (e.g. Wittedrift and New Horizons) close to
Plettenberg Bay.
TOURISM AND NON-CONSUMPTIVE USE
A host of non-consumptive activities take place primarily on the lagoon and Keurbooms
Estuary; the Bitou Estuary is not easily accessible by boat above the N2 bridge.
Plettenberg Bay and its surrounds are one of the major tourist destinations in South
Africa, and yet despite this, the Keurbooms is not specifically marketed as a tourist
destination. Several resorts are available to the tourist and numerous B&Bs and
guesthouses also provide accommodation. Many tourists own property close to the
estuaries and are frequent visitors throughout the year. There are also a large proportion
of permanent residents who choose to live here.
Activities that take place include:
• Appreciating nature – includes rest and relaxation, swimming, walking, canoeing,
power boating, bird watching and picnics. Guided tours with an educational slant are
offered on board two motorized barges.
• Water sports – predominantly water skiing above the N2 bridge on the Keurbooms
Estuary. Kite boarding, windsurfing and sailing may also take place.
• Sporting events – although the SA National Canoeing Championships have been held
on the Keurbooms there is considerable potential for it to host additional events such
as open water swimming, rowing and sailing (in the lagoon area).
Potential activities identified during stakeholder meetings include:
• Formal walking trails through the Keurbooms Nature Reserve.
• Educational workshops for school groups to create an awareness of estuaries.
• Snorkeling trails linked to the Knysna seahorse.
• Additional organized sporting events.
• Package holidays that include a variety of activities associated directly or indirectly
with the estuaries.
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CHAPTER 6 – WATER QUANTITY AND QUALITY
MANAGEMENT OF THE CATCHMENT
The Keurbooms/Bitou catchment’s management structures consist of a number of
national, local and municipal structures. These include the National Department of
Environmental Affairs, inclusive of the Directorate Marine and Coastal Management, the
Provincial Department of Environmental Affairs and Development Planning, the National
and Provincial Department of Water Affairs, other National and Provincial offices of
departments/directorates, e.g. Agriculture, Forestry, Tourism and Land Affairs, and the
Bitou Municipality within the Eden District Municipality.
CATCHMENT DESCRIPTION
The Keurbooms and Bitou river catchments are located in the Gourits Water
Management Area (WMA) 16. The catchments of these two rivers have been measured at
between 1 085 and 1 270 km2, with the Keurbooms being estimated at 70 km in length
and the Bitou River at 23 km. The rivers drain the K60 catchment, which includes
quaternary catchments K60A, B C, D, E and F. A small tributary which falls within
K60G also forms part of the Bitou catchment, and flows directly through the Plettenberg
Bay Sewage Treatment Works (STW) at Gansevalei. It should be noted that the Piesang
River also forms part of K60G, but forms part of an independent catchment and estuary
and not part of this study.
Plettenberg Bay receives rainfall all-year-round with peaks in autumn (March/April) and
spring (August to November. The higher rainfall for Plettenberg Bay in spring (dominant
rainfall period) is a product of the late winter frontal systems together with the effect of
orographic rain resulting from the proximity to the coastal mountains. The rain is mainly
cyclonic and orographic, while thunderstorms are rare. Winter rainfall is associated with
the increase in cold fronts (east moving cyclones) passing over the coast.
The only major dam in the catchment is the Roodefontein Dam, which was raised to
2x106 m
3 capacity in 2003. Environmental releases of 0.31x10
6m
3 are made from this
dam to meet requirements at IFR5 downstream of the confluence of the Keurbooms and
Palmiet rivers. Farm dams are mostly situated in the Upper and Lower Keurbooms River
and Piesang River. The Bitou Municipality’s water sources are shown in the table below.
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Town Current source of supply Future source of supply
Plettenberg Bay Pumping from the Keurbooms River, just below the
confluence with the Palmiet; Roodefontein Dam (also
irrigation abstraction for Jakkalsdraai); and six inland
boreholes (although saline intrusion limits use).
Off-channel storage adjacent to Keurbooms River.
Raise Roodefontein Dam + increase pumping from
Keurbooms during high demand periods.
Keurboomstrand Keurbooms aquifer via wells and boreholes. Off-channel storage in Matjies River. Share of Bufels
River Dam. Obtain water directly from Plettenberg Bay
works.
Kurland Small pool in Wit River, run-of-river abstraction. Unknown
Nature’s Valley Natural pool in Groot River; run-of-river pumping
scheme.
Unknown
Land-use in the upper catchment is predominantly natural forest, mountain fynbos and
grasslands, while the middle and lower catchments are used more extensively for
agriculture, residential and recreational purposes. No significant increases in irrigation,
forestry or farm dams are expected up to 2025.
ECOLOGICAL STATUS
RIVERS
Biological monitoring activities of the Keurbooms and Bitou rives were undertaken as
part of a provincial initiative between DWA and CapeNature in order to fulfil the
objectives of the national River Health Programme (RHP). The information products
generated by the RHP assist in distinguishing between aquatic ecosystems exposed to
sustainable utilization and those experiencing ecological deterioration. It also allows for
subsequent audits of management strategies and actions implemented to improve or
maintain the ecological status of aquatic ecosystems. The RHP determines the ecological
state of river ecosystems in South Africa by evaluating physical drivers such as
geomorphology, water quality and habitat integrity, as well as biotic indicators such as
fish, macroinvertebrates and riparian vegetation. Results of the monitoring activities at
two sites are presented below.
Keurbooms River RHP site: K6KEUR-RHINO
• Macroinvertebrates: This site is characterized by a high species diversity, with a high
sensitivity score. The results show that this site is in a Natural condition.
• Geomorphology: The Geomorphological Index (GI) shows that this site is in a C
category in terms of its geomorphological state. Clearing the recruits of black wattle is
needed and would require effective management.
• IHI: A number of abstraction pipes were seen at the site, with serious modifications to
the non-active channel. A large portion of the left-hand bank has been modified. A
moderate infestation of alien vegetation was seen in the riparian zone.
Bitou River site: K6BITO-WITTE
• Macroinvertebrates: Analysis not undertaken as suitable biotopes were not available
for sampling.
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• Geomorphology: No results shown.
• IHI: Modification of flow evident by two water abstraction devices and two bridges.
The riparian zone appeared highly susceptible to erosion.
WETLANDS
A large number of freshwater wetlands are found within both the river catchments, with
58 wetlands having been surveyed. Storage in farm dams and direct abstraction for fruit
farming, pasture cultivation, forestry and alien plant infestations, have resulted in the
degradation of several wetlands. These impacts have also resulted in the disturbance of
the riparian zones within the catchments.
Quaternary catchment K60D was rated as having the highest number of wetlands and
river-associated riparian systems that remain in a good condition, while K60E was the
poorest with a large plantation block (Keurbooms State Forest) being cultivated directly
within the wetlands, and resulting in eroded areas. As catchment K60D is the principal
water source for the Keurbooms and Bitou Estuaries, the maintenance of its wetlands are
of paramount importance. The largest wetlands are found within K60F, i.e. the Bitou
catchment.
WATER QUANTITY
Thirteen gauging stations or plates have been used to record flow data for various periods
starting in 1961. These are mostly located along the upper and lower reaches of the
Keurbooms River. Peaks in run-off volumes are evident throughout the year. Although
the estuary is flood tide dominated, with the scour by tidal flows removing wave
deposited sand to maintain the inlet channel and allow tidal exchange, river floods also
have an important function. Past studies have noted that the Mean Annual Runoff (MAR)
of the Keurbooms River was highly variable and mirrors rainfall in the region. However,
all studies agree that the lowest runoff is recorded at times when the water demand is
highest.
Instream Flow Requirements (IFR), i.e. the flow portion of the Ecological Reserve (or
Ecological Water Requirements), for the Keurbooms Estuary were estimated at
approximately 144 x 106 m
3 per annum or 77% of the present day MAR estimated in
1999 at the estuary. A conservative approach was followed due to the paucity of
information, with results indicating that the estuary required 100% of present day flows.
These figures were updated during the Rapid Reserve study of 2007.
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ECOLOGICAL WATER REQUIREMENTS
BACKGROUND
The NWA (Chapter 3, Part 3) provides for the protection of significant water resources
through the Reserve. The Resources Directed Measures (RDM) Directorate is the Chief
Directorate within DWA tasked with the responsibility of ensuring that Reserve
requirements, which have priority over other uses in terms of the Act, are determined
before licensing applications can be processed, particularly in water-stressed
catchments. Reserve determinations can be conducted at a Desktop, Rapid, Intermediate
or Comprehensive level. Each level of determination entails a more detailed (higher
confidence) investigation than the previous level. These determinations have to take place
before the water allocation process (compulsory licensing) can proceed. Once Reserve
requirements are available, the allocable resource could be determined and water use
applications evaluated. This means that human (Basic Human Needs Reserve) and
ecological requirements (Ecological Water Requirements, EWR, or the Ecological
Reserve) need to be met before flow can be harnessed for other users.
One of the first steps of the Ecological Reserve process is Ecological Classification. This
step refers to the determination and categorization of the Present Ecological State (PES)
of various biophysical attributes relative to the natural unimpacted reference condition.
Once the PES of these variables has been determined, the EcoStatus is assigned
according to the classification shown in the table below. Once the EWR has been
determined, the estuary will be assigned a Recommended Ecological Category (REC),
which is the state that should be achieved via management interventions.
KEURBOOMS ESTUARY RESERVE ASSESSMENT
A Rapid (desktop) Reserve determination was conducted for the Keurbooms Estuary
consisting of the Keurbooms and Bitou river arms in 2007. For the purposes of the
Reserve study, the geographical boundaries of the estuary were defined as follows:
• Downstream boundary: Estuary mouth (34° 2'31.99"S, 23°23'2.53"E);
• Upstream boundary – Keurbooms arm: Approximately 12.5 km upstream of the
mouth (33°57'8.04"S, 23°24'6.51"E);
DEVI ATION FROM
REFERENCE CONDITIONSA- F CATEGORIES SCORE
A ? 92.01
A/B >87 .4 and <92.01
B 8 2.01 – 87 .4
B/C >77 .4 and <82.01
C 6 2.01 – 77 .4
C/D >57 .4 and <62.01
D 4 2.01 – 57 .4
D/E >37 .4 and <42.01
E 2 2.01 – 37 .4
E/F >17 .4 and <22.01Serious change
No cha nge
Small change
Moderate change
Large change
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• Upstream boundary – Bitou arm: Approximately 12.8 km upstream of the mouth
(33°59'58.44"S, 23°20'27.49"E); and
• Lateral boundaries: 5 m contour above mean sea level along the banks.
The Rapid Reserve study relied on existing data and no new data were collected. The
accuracy of the study depends largely on the accuracy of the simulated runoff data and
measured flow data. River flow data from the Keurbooms River were available from
November 1997. The overall confidence in the hydrological data provided to the study
team was considered to be Medium.
The Estuarine Health Index (EHI) score for the estuary indicated that the estuary’s PES is
in an A/B Category. The estuary has been identified as important from a biodiversity
conservation point of view and is listed as a Desired Protected Area in the C.A.P.E.
Estuaries Conservation Plan. It should therefore be managed as a Category A system, i.e.
the REC should be A. However, the system cannot be rehabilitated to a Category A due
to the pressures contributing to the present state of the estuary. Thus, Category A/B,
representing a largely natural state, was considered to be the REC.
The quantification of Ecological Reserve Scenarios was undertaken as part of the Reserve
assessment (see table below). The evaluation of the simulated runoff scenarios was used
to derive the REC, which was defined as the runoff scenario that represents the highest
reduction in river inflow that will still protect the aquatic ecosystem of the estuary and
keep it in the required category. In evaluating Future Scenarios 1 to 4 it was assumed that
only river inflow from the Keurbooms catchment will be reduced and that all other
related anthropogenic activities (e.g. fishing, bait collection, power boating and human
disturbance) will remain at present levels. Taking the above into account, Scenario 1 was
selected as the REC for the Keurbooms Estuary as this scenario will maintain the
estuary in an A/B category with less impact on the environment (with only 8 % of the
MAR reduced from reference state), while allowing some use of the estuary.
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The estuarine specialists who were a part of the Reserve study team also concluded that
Future Scenario 2 probably does not pose a serious risk to the health of the
Keurbooms/Bitou Estuaries, but that more data will be required over the next few years
to increase the overall confidence in the study.
PRELIMINARY RESERVE TEMPLATE (APRIL 2010)
The draft Preliminary Reserve template (see below) was obtained from Chief Directorate:
Resource Directed Measures (CD: RDM) at DWA in April 2010, and conditions and
background are shown below. Note that upon completion, these values will be signed by
the Chief Director of the CD: RDM, and Gazetted for implementation to manage the
Keurboom and Biotu Estuaries.
*Keurbooms Estuary includes both the Keurbooms and Bitou systems.
To meet the EWR, there had to be some assumptions and limitations on the hydrology.
There was an agreed interim requirement that the diversions be reduced or stopped when
the river flow decreases below 0.3 m3/s and the diversion capacities were reduced by a
22/24 hour factor to account for breakdowns or power supply. It was also proposed that
the river inflow to the Bitou Arm of the Keurbooms system should remain similar to the
present state because: the Bitou Arm comprises an important, ecologically sensitive
wetland; the baseflows from the Bitou River are very low and it would be very easy to
remove all flows to the Bitou Arm of the estuary; the upper part of the Bitou Arm is very
narrow and shallow and potentially very sensitive to changes in flows; and due to the
Na me De scription
Keurbooms
MAR
(MCM/a)
Bitou
MAR
(MCM/a)
Combine d
MAR
(MCM /a)
% natural
M AR PES
Re ference Reference Con dition 174 58 232 100% A
PresentPresent State, including a diversion of 0. 1 m
3/s
to Pletten berg Bay164 51 215 92.70% A/B
Future
Scenario 1
As at Present State but the diversion is
increased to 0.45 m3
/s , no off-channel
s tora ge, 0. 145 m3
/s to Roode fontein,
include Rive r EWR
1 63 5 1 214 92. 20% A/ B
Future
Scenario 2
As at Present Stat e but the diversion is
increase d to 0.45 m3/s with off-ch annel
storage, 0.29 m3/s to Roo defontein, inclu de
River EW R
157 51 208 89.70% A/B
Future
Scenario 3
As at Present Stat e but the diversion is
increased to 0.65 m 3/ s a bst raction
(unconstrained), include River EWR
148 51 199 85.80% B
Future
Scenario 4
As at Present Stat e but the diversion is
increased to 1 .0 m3/s (u ncon strained), include
River EW R
140 51 191 82.30% B
Water
re sourceW MA
Quaternary
catchmentPES EIS R EC
vMAR
(MCM)
Reserve (% of
vM AR)
Level of Reserve
Dete rmination
Keurbooms
Estua ryGo uritz K60E/F A/B High A/B 232 92.2 Rapid
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absence of data (i.e. only one hydrographical station located in the lower part of the Bitou
Arm) no recommendations could be made regarding future abstraction from the Bitou
catchment.
If the scenario recommended by the Rapid Reserve Determination study were to be
implemented, it was recommended that the following mitigation measures be investigated
(with full stakeholder participation) and incorporated in the license agreement between
the Bitou Municipality and DWA:
1. Bitou Drift: The drift through the Bitou River should be removed.
2. Northern floodplain of the lower Bitou Estuary: Remove all exotic trees; no further
development; and remove the old gravel road to the south of the R340.
3. Southern floodplain of the lower Bitou Estuary: Remove all exotic plant species;
remove the infilling; and create a buffer zone (~ 10 m wide separating the wetland
from the agricultural activities on the floodplain).
4. Road Bridge across the lower Bitou Estuary: Remove concrete piers of the old road
bridge and establish connection with old Bitou channel.
5. Middle reaches of the Keurbooms Estuary: Remove all alien trees; establish a buffer
adjacent to the estuary and restrict new development.
6. Upper reaches of the Ganse Spruit: Remove exotic vegetation from the stream bed.
7. The Ganse Spruit Wetlands: Install large culverts in the roads to allow the free flow of
surface water through the wetlands; and remove all exotic invasive tree species.
8. Earthen barricades across tidal channels in the Bitou Arm: Remove earthen
barricades to restore connectivity on the supratidal marsh; and maintain freshwater
flow from northern sections into the supratidal marsh south of the R340.
9. Middle reaches of the Bitou Estuary: Remove exotic tree species; allow the artificial
canal to naturally silt up; allow salt marsh to naturally re-colonise the extensive
grasslands; and insert culverts below the road bisecting the floodplain to link up the
old channels.
10. Old Cape Road canal: Increase the width and depth of the canal to facilitate flushing
of the Bitou.
11. Development of an Estuary Management Plan: It is also recommended that an
Estuary Management Plan (EMP) be developed for the Keurbooms Estuary (includes
Bitou Estuary).
PRESSURES/RISKS/THREATS
Pressures currently contributing to the present state of the Keurbooms and Bitou
Estuaries, in terms of water quantity and quality issues are fishing and bait collecting
activities, human disturbance in and around the estuary (wastewater discharge;
recreational activities), structures in the intertidal and supratidal (floodplain) area and
flow reduction from the Keurbooms and Bitou catchments (abstraction and
impoundments/dams.
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CHAPTER 7 - CLASSIFICATION, ECONOMIC VALUE,
PROTECTION AND REHABILITATION
CLASSIFICATION
The Keurbooms has been ranked as the 18th
most important estuary in South Africa in
terms of biodiversity with an overall importance score of 88 out of a possible 100. An
A/B management class has also been ascribed to the system based on the freshwater
requirements. In order to maintain the system in the A/B class, the Rapid Reserve
Determination study recommends a scenario where abstraction or diversion of freshwater
(to Plettenberg Bay) can be increased to 0.45 m3/s from the present diversion of 0.1 m
3/s.
A botanical rating system that takes functional importance, species richness, plant
community type richness and plant community type rarity into account resulted in the
Keurbooms system being ranked 27th
out of 30 warm-temperate estuaries, with a rating of
235. The top ranked warm-temperate estuary is Knysna with a rating of 360. The
Keurbooms system does not rank in the top 36 estuaries in the country in terms of
botanical importance.
ECONOMIC VALUE
The following economic values have been placed on the Keurbooms Estuary:
Subsistence - ranked 7th
amongst temperate systems with a value of R379 006 per
annum.
Property – ranked 10th
amongst temperate systems in terms of property value related to
estuaries with a value of R399 million.
Tourism – ranked 2nd
amongst temperate systems in terms of tourism value attributed to
estuaries with a value of R400 million per year.
Nursery (protection of juvenile organisms) – ranked 11h amongst temperate systems
with a value of R13.8 million per annum.
Existence – the Keurbooms does not rank amongst the top 40 temperate estuaries.
PROTECTED AREA STRATEGY AND POTENTIAL
PROTECTION OF HABITAT TYPES
Targets for the protection of estuarine habitat types (as a percentage of the total estuarine
habitat measured in hectares) found in the Keurbooms are supratidal salt marsh (30%);
intertidal salt marsh (40%); reeds and sedges (20%); sand/mud banks (40%); submerged
macrophytes (40%); and estuary channel (30%). The overall percentage of all habitat
types combined that should be protected is 30% of the total available 25 095 hectares.
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PROTECTION OF FISH AND BIRD SPECIES
Targets for the protection of fish and bird species (as a percentage of the total population)
have been set at 50% of the population of red data (threatened) species; 40% of the
population of exploited species; and 30% of the population of all other species. Amongst
the bird species it is only the African black oystercatcher that is a listed threatened
species with the remaining assemblage falling under the 30% protection target. Amongst
the fish it is only the Knysna seahorse that is endangered, and all fish assumed to feature
prominently in fishermen’s catches, such as dusky kob, spotted grunter, white steenbras
and bait species such as mullet are targeted for 40% protection of the population.
TYPE OR LEVEL OF PROTECTION
In order for conservation targets and goals to be achieved, 80% of temperate estuaries
needed some form of partial protection rather than a few with total protection. The partial
protection of 80% of estuaries is deemed desirable from a management perspective, in
that it would facilitate the introduction of an almost universal sanctuary zone in each
estuary, which is marked by standard markers, which in turn would facilitate public
awareness about the estuarine protection system.
Initial guidelines for the conservation of estuarine biodiversity required that estuaries be
assigned to one of three categories, namely Estuary Protected Areas (EPAs), Estuary
Conservation Areas (ECAs), or Estuary Management Areas (EMAs). However, due to
complications that arise between fully and partially protected systems with respect to
national legislation and the subsequent administration of EPAs and ECAs it has been
recommended that the above categories be scrapped and that zonation be used instead as
a general strategy in the management of estuaries. Essentially this means that the
estuaries selected to form part of an overall protection network should contain a
sanctuary zone and should receive sufficient protection and sufficient quantity and
quality of freshwater inflows to be maintained in an appropriate state of health.
The zonation strategy means that individual estuaries may contain a fully protected
(sanctuary) area, which would include terrestrial margins, and a conservation area that
would be zoned according to the vision and objectives/requirements for that estuary.
Sanctuary areas would fulfill the same function as an EPA and as such would have to be
set up and managed by an organ of the state. Conservation areas may be managed by a
wide variety of styles within a co-management setup where the community and an
estuary management forum are the main role players.
THE KEURBOOMS IN PERSPECTIVE
Based on the findings of Turpie and Clark (2007), the following can be said about the
Keurbooms/Bitou estuaries with regards to requirements in terms of protection:
• The Keurbooms is one of the core set of temperate estuaries required to meet the
targets for biodiversity protection of estuarine resources.
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• Targets for the protection of habitat types are as follows; supratidal salt marsh (30%);
intertidal salt marsh (40%); reeds and sedges (20%); sand/mud banks (40%);
submerged macrophytes (40%); and estuary channel (30%).
• The recommended extent of undeveloped margin is 50%.
• The recommended minimum water requirement falls under the A/B management
class.
RESTORATION/REHABILITATION
A workshop attended by estuarine scientists and managers was held to determine which
temperate estuaries should be prioritized for rehabilitation and which issues should be
addressed in each estuary. Thirty-nine estuaries, including the Keurbooms, were given a
HIGH priority status for rehabilitation. According to the consensus opinion at the
workshop the single requirement for rehabilitation on the Keurbooms Estuary is clearing
of alien vegetation. Interestingly there is no mention of restoration of areas that have
undergone inappropriate bank stabilization, but the report pre-dates the 2007 floods that
caused extensive damage and resulted in large areas of the banks in the lower-reaches
being stabilized by property owners. There is also no mention of the rehabilitation of the
Bitou wetlands, which is seen as a priority by this report; this can be accomplished in
cooperation with landowners and NGOs such as Working for Wetlands.
CLIMATE CHANGE
There are several threats associated with climate change that are of particular relevance to
estuaries, their users and the surrounding area. These include decreased rainfall (drought),
increased rainfall and frequency of freshwater floods, increased water temperature
(marine/estuary), sea-level rise and increased frequency and intensity of storm events.
These are all relevant to the Keurbooms/Bitou area as drought can affect farmers and the
availability of the ecological reserve, flooding events can be devastating in the area,
increased temperature affects the survival and distribution of species and sea-level rise
and storm events pose a threat to landowners and infrastructure, either on their own or
when occurring together.
The Western Cape Provincial Spatial Development Framework takes climate change
into account and categorically states that:
“No further urban development shall be permitted on open coast lines that are
vulnerable to erosion, inlets that are susceptible to increased storm activity, river
banks that are liable to flooding, coastal buffer zones and ecological setback lines in
estuaries and below the 1:50 year floodlines (erven) and the 1:100 year floodline
(building platform).”
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CHAPTER 8 - THE WAY FORWARD: OBJECTIVE II
LOCAL ESTUARY MANAGEMENT FORUM
Objective II involves the process of formulating an Estuary Management Plan (EMP) for
the Keurbooms and Bitou Estuaries. The EMP should be implemented with the help of a
constituted local management institution, which represents all the relevant stakeholders
and their interests. This management institution would take the form of an Estuary
Management Forum (EMF), comprising a chairman, technical working groups for key
result areas (Biodiversity conservation; Exploitation of living resources; Land-use and
infrastructure development; Water quantity and quality; Institutional and management
structures; Tourism; Sustainable livelihoods; and Education and awareness) and the
forum itself consisting of all stakeholders.
The technical working groups should ideally include representatives from the authorities
who have a mandate and executive powers within the specific sector as well as competent
natural or social science specialists acting in an advisory role. It is likely that CapeNature
will be the lead authority.
THE ESTUARY MANAGEMENT PLAN
Key to the formulation of an EMP will be the organization of a stakeholder workshop in
order to develop a vision and objectives for the Keurbooms and Bitou systems based on
the Situation Assessment (this report) and the future needs and desires of the
stakeholders. These outcomes together with the assessment provided by Turpie and Clark
(2007), the Rapid Reserve Determination study and the C.A.P.E. Generic Framework for
EMPs will be used to formulate the EMP.
Essentially the following tasks will be performed for Objective II:
• Assist in setting a Vision and Strategic Objectives for the Keurbooms and Bitou
Estuaries.
• Develop a range of Management Strategies to achieve the Vision and Objectives.
• Prepare an Estuary Zonation Plan (EZP) and Operational Objectives based on the
above.
• Identify Management Action Plans (MAPs) to achieve all strategies and operational
objectives including implementation procedures (includes human and financial
resources).
• Propose an institutional structure (i.e. the EMF) to guide the implementation of the
EMP.
• Develop a monitoring and evaluation programme including a description of a process
for reviewing the management plans.
• Identify research priorities.
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ISSUES RAISED BY STAKEHOLDERS
The following issues were identified during stakeholder meetings. These will be
addressed in the EMP and do not appear in any particular order:
• An improved zonation plan is required (includes indication of floodlines, wake-free
and skiing zones).
• Estuary-specific by-laws are urgently required so that issues such as houseboats and
wake-free zones can be enforced. Speeding boats below the N2 bridges are a threat to
safety and interfere with other recreational activities such as fishing. Area above N2
bridge on Keurbooms is covered by Keurbooms Nature Reserve and enforced by
CapeNature Ordinance.
• Wake-free zones need to be indicated as such and NOT as 10 kph.
• Implementation of the Ecological Reserve.
• Alien vegetation clearing, both in the catchment and within estuary area.
• Contaminated freshwater runoff from farmlands and commercial forestry plantations.
• Conservation of wetlands (includes saltmarsh) associated with both systems.
• Compliance monitoring needs to be improved.
• Water licensing and use (abstraction) needs to conform to Reserve Determination
recommendations.
• Sewage pump stations on eastern side of Keurbooms cannot cope with peak season
loads.
• Incorporation of 1:100-year floodline in zonation to restrict irresponsible
development.
• Consider making the Bird Sanctuary a no-go area to reduce disturbance.
• General monitoring of water quality, particularly at sites where sewage may enter the
system (e.g. Rietvlei and Gansvlei areas).
• A Municipal environmental officer is required.
• More stringent control over bait collecting activities (includes illegal selling).
• The availability of recreational fishing permits over the weekend was viewed as
problematic and could impact on tourism.
• Threatened species such as the Knysna seahorse and pansy shell and their preferred
habitat need to be protected (adjacent to the Keurbooms Lagoon Caravan Park for
pansy shells and in the region of the confluence for the Knysna seahorse).
• Time taken to obtain authorization to carry out rehabilitation after floods is excessive
and leads to illegal activities; process needs to be streamlined and a standardized
approach adopted to cover instances of repeated damage after each flood event.
• No fishing competitions.
• Education and awareness programmes need to be initiated (regulations, importance of
estuaries etc.). Adopt an approach of education before issuing of fines.
• Abandoned hake long-line vessels on the Keurbooms need to be removed (safety and
possible pollution source).
• Impact of a possible desalination plant.
• Reinstate financial assistance from the Municipality to help with CapeNature’s
management actions outside of the Nature Reserve.
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• Additional field rangers (two) required so CapeNature can operate effectively.
• Investigate feasibility of making funds from boat licenses available for management
actions.
• Compliance of CapeNature personnel with skippers’ license requirements.
• Feasibility and impact of dredging to deal with excessive sediment loads.
• The proposed N2 bypass route through the lower reaches (SANRAL) needs to be
considered.
• Impact of a major dam in the Keurbooms and/or Bitou catchment.
• All management interventions that affect landowners need to be a part of a public
participation process, i.e. cooperative and not prescriptive.
• Feasibility of off-stream storage of excess flood waters to offset shortages during
times of drought.
• Clearing of debris (from alien clearing) in the catchment to reduce damages from
floods.
• Feasibility of landowners undertaking alien clearing (using own labour) as long as
funding is made available.
• Clearly indicate which government departments are responsible (mandated) for which
management interventions.
• Need to highlight the Keurbooms as a unique tourist attraction (e.g. same as
Robberg).
• Investigate additional activities that can add to attraction of the Keurbooms as a
tourist destination (e.g. hiking trails and sporting events).
• Bank erosion, from clearing of aliens, is an issue in the upper Keurbooms catchment.
• Capacity of Bitou sewerage treatment works to cope with increased development.
• Government involvement is required in the long term to ensure implementation.
In addition to the above, the mitigation measures recommended by the Reserve
Determination study will be included in the EMP.
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LIST OF TABLES, FIGURES AND PLATES
TABLES
Table 4.1 Summary of International obligations and their relevance to estuarine
management.
Table 4.2 Summary of national legislation and its relevance to estuarine management
(from Taljaard 2007).
Table 4.3 Summary of national policies (white papers) relevant to estuarine management
(from Taljaard 2007).
Table 4.4 Themes and Strategic Components of C.A.P.E. (after DMP 2004).
Table 6.1 Details of the quaternary catchments of the Keurbooms catchment K60.
Table 6.2 Present and future water sources of the Bitou Municipality.
Table 6.3 Monthly flow volumes (x 106 m
3) for Newlands K6H019A01 gauging station
for 1997 to present (# indicates incomplete data set).
Table 6.4 MAR values for the Keurbooms and Bitou rivers (after Bornman and Adams
2005).
Table 6.5 Generic ecological categories for EcoStatus components (DWAF 2008;
modified from Kleynhans et al. 2005).
Table 6.6 Generic ecological categories for EcoStatus components (Kleynhans et al.
2005).
Table 6.7 A summary of the mean annual runoffs (MAR) of the various Simulated
Monthly Runoff Scenarios used for this Rapid level determination with the PES under
each scenario.
Table 7.1 Target percentages for the protection of selected estuarine fish and bird species
(after Turpie and Clark 2007).
FIGURES
Figure 2.1 The Keurbooms and Bitou Estuaries and the Keurbooms lagoon or basin
(from CSIR 2007).
Figure 2.2 Structures associated with the Bitou and Keurbooms Estuaries and the 100
and 1 000 m coastal protection buffer zones.
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Figure 3.1 Vegetation and habitat map of the Bitou Estuary and the lower and middle
reaches of the Keurbooms Lagoon and Estuary (Bornman and Adams 2007).
Figure 4.1 Conservation status of the Bitou Municipal Area.
Figure 4.2 Bio-regional Framework of the Bitou Municipal Area.
Figure 6.1 Locality map indicating the various quaternary catchments associated with the
Keurbooms / Bitou rivers (from Haigh and Bekker 2005).
Figure 6.2 Mean monthly precipitation over 20 years from 1984 to May 2004.
Figure 6.3 The middle and lower reaches of the Keurbooms Estuary (after Bornman and
Adams 2005).
Figure 6.4 Extent of the Keurbooms and Bitou Estuaries as used for the Reserve
determination study – 5 m contour line not shown (Bitou Municipality 2008).
PLATES
Plate 2.1 The Bitou Estuary showing the remnants of the old N2 bridge (top left), the
floodplain above the bridge on the north bank (top right) and the Rietvlei wetland above
the bridge to the south (middle left); the Gansvlei wetland in the region of the confluence
(middle right); and the Keurbooms Estuary showing the steep gorges in the upper reaches
(bottom left) and the shallow intertidal regions adjacent to the Anath Peninsula (bottom
right).
Plate 2.2 The road bridge and causeway over the Bitou Estuary near Wittedrift (left) and
the extensive sandbanks in the vicinity of Stanley’s Island (left).
Plate 2.3 The upper reaches of the Keurbooms Estuary at Whisky Creek with the
demarcation barrels preventing boats from venturing further upstream (top left and right);
one of the few jetties on the Keurbooms Estuary (middle left); and boats moored on poles
driven into the sediment (middle right) or on makeshift anchors (bottom).
Plate 2.4 Flood damage on the Keurbooms in the middle reaches at Forever Resorts (top
left), the lower reaches (top right) and the upper reaches at one of the CapeNature picnic
sites (bottom).
Plate 2.5 Attempts at bank stabilization in the lower reaches of the Keurbooms Estuary
have met with varying degrees of success.
Plate 3.1 Clearing and stand of Alien Poplar (Populus sp.) trees alongside the Bitou
River just above the upper reaches of the estuary.
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LIST OF ACRONYMS
BAS Best Attainable State
CAP Coastal Action Plan
C.A.P.E. Cape Action for People and the Environment
CapeNature Western Cape Nature Conservation Board
CARA Conservation of Agricultural resources Act (Act 43 of 1983)
CD: RDM Chief Directorate: Resource Directed Measures
CFR Cape Floristic Region
CMP Coastal Management Programme
CPUE Catch-per-unit-effort
CSIR Council for Scientific and Industrial Research
CWAC Coordinated Waterbird Counts
DAFF Department of Agriculture, Forestry and Fisheries
DEADP Western Cape Department Environmental Affairs and Development Planning
DEA Department of Environmental Affairs
DIN Dissolved Inorganic Nitrogen
DO Dissolved Oxygen
DRP Dissolved Reactive Phosphate
DRS Dissolved Reactive Silicate
DWA Department of Water Affairs
DWAF Department of Water Affairs and Forestry
DWEA Department of Water and Environmental Affairs
ECA Estuary Conservation Areas
EFA Enviro-Fish Africa (Pty) Ltd.
EHI Estuarine Health Index
EIA Environmental Impact Assessment
EIS Ecological Importance and Sensitivity
EMA Estuary Management Areas
EMC Ecological Management Class
EMF Estuary Management Forum
EMP Estuary Management Plan
EPA Estuary Protected Area
EWR Ecological Water Requirements
EZP Estuary Zonation Plan
GRI Garden Route Initiative
ICMA Integrated Coastal Management Act (Act 24 of 2008)
IDP Integrated Development Plan
IFR Instream Flow Requirements
IHI Index of Habitat Integrity
IUCN International Union for Conservation of Nature
MAP Management Action Plan
MaP Mean Annual Precipitation
MAR Mean Annual Runoff
MCM Branch: Marine and Coastal Management (DEA)
MCM/annum Million cubic metres per annum
MLRA Marine Living Resources Act (Act 18 of 1998)
MSL Mean Sea Level
NEMA National Environmental Management Act (Act 107 of 1998)
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NGO Non-Governmental Organization
NMMU Nelson Mandela Metropolitan University
NWA National Water Act (Act 36 of 1998)
PES Present Ecological State
PGDS Provincial Growth and Development Strategy
PSDF Provincial Spatial Development Framework
RDM Resource Directed Measures
REC Recommended Ecological Category
REI River Estuarine Interface
RHP River Health Programme
RQO Resource Quality Objectives
SDF Spatial Development Framework
SDP Spatial Development Plan
STEP Subtropical Thicket Ecosystem Plan
STW Sewage Treatment Works
WMA Water Management Area
WULA Water Use License Application
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CHAPTER 1 - INTRODUCTION
1.1 INTRODUCTION
Estuarine ecosystems are not isolated systems. They form an interface between marine and
freshwater systems and are part of regional, national and global ecosystems either directly via
water flows or indirectly through the movement of fauna. In addition to the biota that these
estuaries support, they provide a range of goods and services (uses) to the inhabitants of the
various regions. Disturbances in one estuary can influence a wide variety of habitats and
organisms in the broader freshwater or marine ecosystem. Thus, the interaction between the
systems and users creates a delicate balance, the sustainability of which needs to be addressed
by some form of management plan.
In order to address this balance in a consistent manner in the Cape Floristic Region (CFR),
the Cape Action for People and the Environment (C.A.P.E.) Estuaries Programme has
developed a holistic and inclusive management process representative of all stakeholders.
The programme is governed by a Task Team comprising of officials from C.A.P.E., Cape
Nature, Marine and Coastal Management (MCM), the Department of Water Affairs (DWA),
the Eastern Cape Parks Board (ECPB) and the Council for Scientific and Industrial Research
(CSIR), which heads the technical support group.
The urgent need for Estuary Management Plans (EMPs) became apparent during the
development of the Integrated Coastal Management Act (Act 24 of 2008; ICMA). Estuaries
and the management thereof have not been adequately addressed by past marine, freshwater
and biodiversity conservation Acts. Estuaries and estuary management have been
marginalized due to the fact that they did not fit the ambit of any one government department.
Estuaries and the management thereof now form an integral part of the ICMA, which
identifies the need for the development of EMPs, as these would help to align and coordinate
estuaries management at a local level. According to the ICMA, EMPs need to be developed
in accordance with a National Estuarine Management Protocol. However, until such time as
this protocol is developed, EMPs are formulated along the lines of the C.A.P.E. Generic
Framework for EMPs (van Niekerk and Taljaard 2007).
Enviro-Fish Africa (Pty) Ltd. (EFA) has been contracted by the C.A.P.E. Estuaries
Programme to address the development of an EMP for the Keurbooms and Bitou Estuaries.
This report fulfills the requirements of Objective 1, namely a Situation Assessment.
1.2 TERMS OF REFERENCE
OBJECTIVE 1: SITUATION ASSESSMENT
The consultant is expected to review all existing information in the form of scientific
literature, local research reports and municipal management and planning documents. A map
of the Keurbooms and Bitou Estuaries should be developed identifying different habitats and
potential and existing management zones. The map should identify and record all
developments in at least a 500m zone surrounding the estuary. The possible direct impacts of
these and other local developments should be noted.
The description of the current situation should include information on:
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• Legal requirements relevant to the specific estuary;
• Requirements stipulated under existing institutional Management Strategies such as
Catchment Management Strategies, IDP, SDF, RAMSAR & National Heritage Site
Strategies and Protected Area & Conservation Plans (e.g. C.A.P.E. Estuaries) relevant
to the study area;
• The Biophysical environment (present ecological health and important physical
processes);
• The Socio-Economic environment (e.g. demographics & economic profile, land-use and
planning provisions, cultural & heritage resources, water supply & demand, waste
management etc.);
• Conservation planning;
• The exploitation of living resources;
• Mariculture activities;
• Resource Directed Measures, e.g. Classification, Reserve and RQOs; and
• Current institutional structures governing estuary issues.
The estuaries should be represented spatially in the form of GIS Maps indicating the
following (some of these are not applicable to the Keurbooms/Bitou, e.g. mariculture and
solid waste dump sites):
• Important biophysical features
• All protected/conservation areas
• Areas earmarked for rehabilitation
• Land-use and planning provisions of surrounding lands
• Infrastructure
• Cultural & heritage sites
• Recreational activities
• Living resource exploitation
• Mariculture activities
• Wastewater discharges
• Stormwater drains
• Solid waste dump sites.
1.3 PROJECT TEAM
Overall responsibility for the project lies with Enviro-Fish Africa (Pty) Ltd. The project and
team will be managed by Dr Tim Andrew of EFA; Dr Aidan Wood from Gleneagles
Environmental Consulting CC is the project coordinator and will also provide specialist input
with regards living resource exploitation and bio-physical & socio-economic aspects; Drs
Patsy Scherman and Brian Colloty from Scherman Colloty & Associates will provide
specialist input with regards the catchment, water use and water requirements; and Mr
Russell Chalmers, a PhD candidate at Rhodes University, will be responsible for all mapping
and GIS work.
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CHAPTER 2 – PHYSICAL DESCRIPTION
2.1 INTRODUCTION
The Keurbooms and Bitou estuaries are located close to the coastal town of Plettenberg Bay
and both feed into what is known as the Keurbooms lagoon or basin, a 500 m wide stretch of
water (also known as a back-barrier lagoon) separated from the sea by a prominent berm,
prior to it flowing out to sea (Figure 2.1). The confluence of the Bitou and Keurbooms
estuaries is approximately 3.5 km from the mouth. The Bitou River is 23 km long, with its
source at Buffelsnek, and is tidal for 7.2 km from the confluence to the causeway at
Wittedrift. The Keurbooms River is approximately 85 km long (Harrison et al. 2001), with its
source at Spitskop in the Outeniqua Mountains (Duvenage and Morant 1984), and is tidal for
approximately 8.5 km from the confluence to about 1.5 km upstream of Whiskey Creek. The
combined catchment has been estimated at anywhere between 1085 and 1188 km2 (Heydorn
and Tinley 1980; Day 1981; Reddering 1981).
Figure 2.1 The Keurbooms and Bitou Estuaries and the Keurbooms lagoon or basin (from
CSIR 2007).
Major tributaries of the Keurbooms are the Hartbees, Duiwelsgat, Palmiet, Klein, Diep,
Witels, Kwaai, Peters, Bos and Kykoerie Rivers. A few minor streams flow into the lower
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Bitou, but the major catchment tributaries are the Kleineiland, Petrus Brand and Rondebos
Rivers (Duvenage and Morant 1984).
Due to the close association between the two estuaries and the fact that they meet at the
confluence prior to the permanently open mouth, the two systems and the lagoon are often
collectively referred to as the Keurbooms. In this report, when using the term Keurbooms it
will be referring to both systems; when one or the other is specifically being referred to the
term “Estuary” will be used after the name. The Keurbooms is a warm-temperate estuary,
regarded by Whitfield (2000) as being in good condition, although he highlights a major
threat as being the construction of a large dam in the catchment of the Keurbooms River
(most likely on the major tributary - the Palmiet River). Eden to Addo (2010) also refer to the
possibility of a storage dam in the upper Bitou catchment. Harrison et al. (2000) class the
Keurbooms as a warm-temperate, permanently open, medium-large, Type F barred system
(supratidal barrier), whose ichthyofauna, water quality and aesthetics are rated as good, good
and moderate respectively. The upper reaches of the Keurbooms Estuary above the N2 bridge
are spectacular and the moderate aesthetics rating is thought to be due to the extensive urban
development on the middle to lower reaches and lagoon area.
The Bitou Estuary above the N2 is characterized by an extensive floodplain and wetland
complex, while the Keurbooms Estuary above the N2 has no floodplain and is characterized
by steep gorges (Plate 2.1). Extensive intertidal areas, dominated by sandbanks, mudbanks,
saltmarsh and freshwater creeks, characterize both estuaries below the N2 and the lagoon
area. The tidal flow of the Bitou Estuary is restricted by the remnants of the old N2 bridge
(located upstream of the existing bridge) that was washed away in the 1940 floods.
There are two statutory conservation areas, both provincial nature reserves administered by
CapeNature, namely the Keurbooms River Nature Reserve (905 hectares) and the Keurbooms
River Seagull Breeding Colony (39 hectares). Neither of these reserves incorporates any of
the estuary water body, but a substantial portion falls within the defined estuarine area. In
addition to this, there are significant areas of private land that are managed for conservation
purposes (private nature reserves, Middle Keurbooms Conservancy) and the Eden to Addo
Corridor Initiative is looking to protect plant and animal habitats through establishing
biodiversity corridors on privately owned land between formally protected areas.
Analysis of data collected during a survey between 1994 and 1996 showed that land use in
the Keurbooms catchment comprised approximately 15% commercial agriculture
(commercial forestry, improved grasslands, temporary commercial irrigated agriculture such
as orchards, and temporary commercial dryland agriculture) and 85% natural shrubland,
bushland and forest. Very little (<1%) is degraded or developed (includes Plettenberg Bay
area; Harrison et al. 2001). The upper Bitou catchment comprises mostly State owned
indigenous forests; with the rest of the catchment comprising privately owned land (farms,
conservancies, eco-tourism, guest houses and two quarries) with indigenous forest and
cultivated lands (Duvenage and Morant 1984). Between Uplands, Hillview and Wittedrift, a
variety of farming activities take place, including wheat, dairy, vegetables, small amounts of
stock and mixed activities. The lower Bitou catchment comprises mostly farmland, urban
settlements and a sewage treatment works at the head of the Gansevalei.
Aspects dealing with rainfall, runoff, freshwater inflow, flood regimes and the reserve
determination study will be dealt with in Chapter 6, which describes water quantity and
quality issues.
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Plate 2.1 The Bitou Estuary showing the remnants of the old N2 bridge (top left), the
floodplain above the bridge on the north bank (top right) and the Rietvlei wetland above the
bridge to the south (middle left); the Gansvlei wetland in the region of the confluence (middle
right); and the Keurbooms Estuary showing the steep gorges in the upper reaches (bottom
left) and the shallow intertidal regions adjacent to the Anath Peninsula (bottom right).
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2.2 THE EXTENT OF THE ESTUARINE AREA
The C.A.P.E. Estuaries Programme considers the National Water Act (Act 36 of 1998;
NWA) definition of an estuary as the most appropriate. It reads as follows; “a partially or
fully enclosed water body that is open to the sea permanently or periodically, and within
which the seawater can be diluted, to an extent that is measurable, with freshwater
drained from land.” For the purposes of determining the Resource Directed Measures
(RDM), the Department of Water Affairs (DWA) defines the geographical boundaries of an
estuary as follows; “the seaward boundary is the estuary mouth and the upper boundary
the full extent of tidal influence or saline intrusion, whichever is furthest upstream, with
the five meter above Mean Sea Level (MSL) contour defined as the lateral boundaries.”
The extent of the estuary area for the Keurbooms and Bitou Estuaries is shown in Figure 2.2.
The Keurbooms Estuary extends approximately 1.5 km upstream from Whiskey Creek and
the Bitou Estuary extends as far as the causeway over the Wittedrift road. These are the
generally accepted limits, but the exact upper limit of each estuary at any one time will vary
depending on tidal flows in relation to the volume of freshwater entering from upstream. The
seaward extent of the Keurbooms Lagoon is located at the mouth, which varies according to
the location where floods breach the barrier and the subsequent rate of migration in a SW
direction. When the mouth is located east of its existing position, a blind arm of the lagoon
exists in the SW corner; this too is a part of the estuary area.
With regards the lateral terrestrial boundaries, there are several options commonly used to
define the area, namely:
• Floodlines – either the 1:50 or 1:100 year floodlines. These provide a good indication of
the historical extent of floods and therefore areas that pose a risk for developments and
infrastructure. However, these floodlines are not available for many estuaries and also do
not indicate the possible extent of future events that could be more severe due to the
effects of climate change.
• 5 m contour – this may be useful in the context of the projected sea level rise and increase
in the severity of floods and storm events due to climate change. In the context of local
EMPs, the five-meter contour line has its limitations, as the area can either prove to be
extensive for practical implementation, or non-existent where vertical cliffs define the
channel. The 5 m contour line is currently unavailable for the Keurbooms/Bitou systems.
• Coastal protection zone (Figure 2.2) – this zone is defined as a 100 or 1 000 m buffer
zone measured inland from the high water mark and also makes provision for any land
located within the 1:50 year floodline (this may extend beyond the 100 or 1 000 m limit
in certain areas). Essentially, the 100 m zone is defined for areas zoned as urban and the 1
000 m zone is defined for rural (agricultural) areas. It must be made clear that these zones
are designed to restrict certain activities that may interfere with the estuary and its
sensitive riparian areas, but it does NOT mean that no activities may take place. Activities
that should be restricted, or at least assessed prior to authorization are those listed in the
NWA that require a license (e.g. water use), the EIA Regulations (see below) and those
affecting sustainable development and sensitive ecosystems as defined in the principles of
Chapter 1 (Section 2) of the NEMA. These zones do NOT indicate that landowners may
not operate within their boundary, i.e. they do not lose this land, but they must adhere to
sound environmental principles when conducting any activities. For example, all existing
sustainable farming practices that currently take place within the boundaries of existing
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legislation are not affected, and all new ventures only need to conform to sound
environmental principles in order to get authorization to proceed.
• EIA regulations – although not used to specifically define the estuary area, the 100 m
buffer zone also provides an indication of the area in which listed activities are regulated
relative to the high water mark in accordance with the EIA Regulations.
2.3 PHYSICAL STRUCTURES
The road bridge over the Bitou Estuary at Wittedrift and the old causeway immediately
downstream act as obstructions to water flow and essentially form the upper limit of tidal
exchange in the estuary (Plate 2.2). The existing N2 bridge and embankment obstructs more
than 45% of the river width of the Bitou Estuary (Duvenage and Morant 1984). Floods
washed the older bridge away in 1940 and the remaining concrete piers restrict flow in the
northern channel of the Bitou Estuary. Flow was further restricted by the embankment of the
N2, which completely closed off the main channel and forced water to flow through a
secondary channel. A low causeway (no longer in use) is present across the Bitou Estuary
approximately 1.5 km upstream of the N2 Bridge. This causes some constriction to tidal
flows especially at low tides. The N2 bridge over the Keurbooms Estuary does not appear to
affect the orientation of the channel, but may contribute to increased sediment deposition
immediately downstream in the vicinity of Stanley’s Island (Plate 2.2).
Plate 2.2 The road bridge and causeway over the Bitou Estuary near Wittedrift (left) and the
extensive sandbanks in the vicinity of Stanley’s Island (right).
There are three picnic sites, administered by CapeNature, one on the eastern bank and two on
the western bank of the Keurbooms Estuary above the N2 bridge. A rope and three barrels are
strung across the estuary above Whisky Creek warning boats not to proceed further upstream
(Figure 2.2 and Plate 2.3).
There is one slipway above the N2 bridge on the Keurbooms Estuary at Forever Resorts and
seven below the N2 bridge including one on the beach/sandbank at the Keurbooms Lagoon
Caravan Park (Figure 2.2). There are no slipways upstream of the N2 bridge on the Bitou
Estuary and no jetties upstream of the N2 on either the Bitou or Keurbooms Estuaries. There
are two jetties and one boathouse/jetty on the western side of the Bitou channel below the N2
and a slipway on the eastern side. A single long jetty extends from Stanley’s Island towards
the N2 and a further 4 jetties exist on the eastern side of the eastern Keurbooms channel
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below the N2. A small-boat harbour, comprising mooring facilities for over 100 boats and a
slipway are located on the western side below the N2 at the Plettenberg Bay Angling Club.
Although the number of jetties on either system is low, many boats are moored on the east
bank of the Keurbooms Estuary below the N2, on the west bank at Forever Resorts above the
N2 and close to the mouth of the Keurbooms Lagoon (Plate 2.3). These are either tied to
wooden poles secured along the bank or anchored on short lines attached to makeshift
anchors.
2.4 PHYSICAL PROPERTIES
2.4.1 DEPTH
The lower reaches of the Keurbooms Estuary is approximately 3 m below mean sea level
(MSL) and becomes shallower towards the middle reaches (0.9 m below MSL; Huizinga and
Slinger 1999) where the channel to the west of Stanley Island is considerably shallower than
the eastern channel. Upstream of the N2 bridge, average depth is considerably greater with
some sections measuring in excess of 20 m below MSL. The estuary becomes very shallow at
and above Whisky Creek. The depth of the Bitou Estuary varies between 2.7 m below and 0.7
m above MSL, with the deeper sections being located upstream of the N2 bridge. Five
surveys of the mouth of the estuary (Keurbooms lagoon) indicated that the depth varied
generally between 1 and 2 m below MSL (Huizinga and Slinger 1999).
Tidal variation (amplitude) inside the mouth is 1.35 m and decreases to 0.95 m at the N2
bridge (Huizinga and Slinger 1999). The tidal variation in the Bitou Estuary is reduced from
1.35 m at the mouth to 0.85 m at the N2 bridge and 0.38 m at the Wittedrift Bridge. Although
tidal variation occurs throughout the estuarine basin on the spring tide, active tidal exchange
in which the entire water column is flushed occurs primarily in the lower reaches below the
N2 bridges (Huizinga and Slinger 1999).
There is no record of mouth closure occurring at the Keurbooms Estuary, but the mouth
sometimes becomes very shallow. It is also a matter of concern that the estuary becomes very
shallow at places between the mouth and the N2 bridges, which indirectly could contribute to
mouth closure occurring in the future. A major long-term impact of water abstraction from
the Keurbooms and Bitou estuaries can be mouth closure. Enough flow should reach the
estuary to prevent this from happening, which limits the volumes of water that can be
abstracted from the Keurbooms and Bitou rivers. The size and depths of the estuary are such
that closure is unlikely to occur in the near future, but the shallowness of the lower estuary is
a major concern, especially if further reduction in river flow would occur (CSIR 2007).
2.4.2 SEDIMENT PROCESSES AND CHARACTERISTICS
The Keurbooms lagoon lies in the sheltered Plettenberg Bay on the southern Cape coast and
is separated from the sea by a coastal barrier. A mobile tidal inlet through the barrier provides
tidal connections between the lagoon and the sea. The Keurbooms and Bitou Estuaries
occupy two drowned river valleys. The bay of Plettenberg Bay is characterized by a wave
dominated shoreline where very high longshore sediment transport rates are recorded during
southeasterly storms (Reddering and Rust 1994). The surf zone is the main sediment source
of the estuary (Reddering 1999). River floods are important to temporarily scour open inlets
and remove tidal-accumulated sediment from the lower reaches (Reddering 1981; 1999).
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Plate 2.3 The upper reaches of the Keurbooms Estuary at Whisky Creek with the
demarcation barrels preventing boats from venturing further upstream (top left and right); one
of the few jetties on the Keurbooms Estuary (middle left); and boats moored on poles driven
into the sediment (middle right) or on makeshift anchors (bottom).
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Figure 2.2 Structures associated with the Bitou and Keurbooms Estuaries and the 100 and 1
000 m coastal protection buffer zones.
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The tidal prism of the Keurbooms / Bitou estuary is in the order of 1.8 x 106 m
3 (Reddering
1981). The mean spring tidal range in the bay is about 1.6 m (increasing to over 2 m during
equinox spring tides). The neap tidal range is very small in the estuary due to the large
accumulation of sand in the tidal inlet. Due to the constriction of the tidal inlet, the estuary is
flood tide dominated with a tidal range of about 60% of that along the beach (Reddering and
Rust 1994). Annually about 1.5 x 104 m
3 of marine sand enters the back-barrier Keurbooms
lagoon (Reddering 1981). In the Keurbooms estuary the scour by tidal flows removes enough
of the wave deposited sand to maintain the inlet channel and allow restricted tidal exchange.
The main inlet channel consists of an ebb-dominated and a flood dominated sector. The ebb-
dominated channel forms the deepest part of the inlet (3- 5 m below MSL). Since the tide is
ebb-dominated, the flood tide has very little effect on sediment in the ebb channel. The flood
dominated channel (along the northern bank) ranges in depth from 0.5 to 2.5 m below MSL
and flood directed bedforms dominate (Reddering and Rust 1994). The flood tide decelerates
as it enters the back-barrier lagoon and deposits a major fraction of its bedload on the flood
tidal deltas (Figure 2.4). As the inlet migrates southwestwards, the flood deltas accrete
laterally into an elongate sediment body that occupies the entire landward edge of the back-
barrier lagoon to form intertidal sand flats. At present the mouth is located at the extreme
southwest end of the lagoon arm, flush against Lookout Rocks.
The inlet migrates southwestward by erosion of the southern inlet margin and the growth of
the northern margin (Reddering and Rust 1994). The primary reason for the southwesterly
migration of the mouth is the scouring of the southwest spit that occurs on ebb tides as the
flow alters direction to accommodate the 45º angle of the mouth to the coastline (Huizinga
and Slinger 1999). During major events the floodwaters breach the spit at the northeastern
corner (Duvenage and Morant 1984). The effect of small to medium sized floods on the
mouth of the estuary is short-lived, as they do not cause breaching of the sand spit and
alteration in the position of the mouth (Huizinga and Slinger 1999). Several evenly spaced
washover channels are present on the sand barrier and washover sand is an important local
source of marine sand in the estuary (Schumann 2003).
Severe flooding occurs in both systems, with the most recent in 2007 being the most
devastating in living memory. Apart from the major damage to infrastructure located on the
floodplain and scouring of sediment along the course of the estuaries, floods have a major
impact on the mouth in the following ways (CSIR 2007):
• The estuary mouth is deepened and widened by the scouring during flood events.
• The normally complex estuary mouth is temporarily straitened by river floods, but after
the floods the normal channel configuration is re-established by the mouth dynamics and
the long shore transport.
• Floods are playing a major role in the long-term sediment dynamics upstream of the
estuary mouth. Ongoing inland movement of marine sediments takes place during periods
when only minor floods occur, causing a gradual shallowing of the estuary. In the long
term this ongoing sedimentation is counter balanced by flushing of sediments during
major floods. Reduction in occurrence and severity of flooding will therefore probably
result in ongoing sedimentation and shallowing of the estuary. This could eventually lead
to a situation whereby mouth closure might occur.
Sediment in the Keurbooms and Bitou Estuaries consists of fine-grained quartz (sand and
silt), organic material and clay. The Keurbooms River and the lower reaches of the Bitou
River are underlain by Tertiary to Quaternary marine and estuarine terrace gravel and partly
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calcareous sand (Duvenage and Morant 1984). The more extensive supratidal flats lie near
the clay producing sources. These sources are the outcrop of the Cedarberg Shale in the
southern back-barrier lagoon, and the mud bearing Bitou tributary (Reddering and Rust
1994). The Keurbooms River originates in the Tsitsikamma mountain range that forms part of
the Cape Fold Belt. As a result, sediment from the Keurbooms River consists almost
exclusively of quartz sand (Reddering 1981). The drainage basin of the Bitou River is
underlain by semi-consolidated immature sandstone, conglomerate and shale of Cretaceous
age. The sediment yield from this tributary is small but contains clastic suspension material
(clay content between 5 and 25 %; Reddering 1981).
Sediment in the Bitou Estuary is likely to be more resistant to erosion than the sandy
sediment in the Keurbooms Estuary (Reddering 1999). Suspended mud particles entering the
estuary in freshwater, mixes with the saline water in the Bitou Estuary. The presence of
electrolytes in the water causes the clay particles to flocculate and settle from suspension in
the Bitou Estuary (Reddering 1999). Most of the mud from the Bitou Estuary accumulates on
the intertidal saltmarshes and mudflats and very little fine sediment enters the Keurbooms
Estuary from the Bitou Estuary (Reddering 1999).
Meandering tidal creeks traverse the supratidal flats, and during spring high tide form the
water conduits between the estuary and the supratidal flats. Although mostly inactive, these
creeks have a considerable bank full discharge at spring high tide The gradual up-estuary
variation of hydrodynamics and sedimentary conditions has a profound influence on the
behaviour of burrowing organisms.
2.4.3 TEMPERATURE
There is little evidence of vertical temperature stratification, with surface and bottom
temperatures measuring between 12 and 22.9 ºC (Day 1981; Duvenage and Morant 1984;
James and Harrison 2009). This lower limit is likely to be seen during coastal upwelling
events when cold marine water pushes into the system during the flood tide. The normal
temperature regime, which shows a strong seasonal pattern, is between 20 and 25oC in
summer and 15 and 20oC in winter (CSIR 2007). A horizontal gradient exists, with
temperatures increasing upstream; this gradient is known to reverse when there are strong
freshwater flows from the catchment. On average the Bitou Estuary is warmer than the
Keurbooms Estuary.
2.4.4 SALINITY
Day (1981) and Duvenage and Morant (1984) report on salinities ranging from 13 to 34 ppt,
with highest salinities in the mouth region. James and Harrision (2009) recorded surface
salinity between 35 and 15.3 ppt, which was slightly lower on average than values for bottom
waters (35 to 22.6 ppt). This type of stratification is more evident above the N2 bridges and
more pronounced in deeper areas and over the neap tide cycle; salinity decreases as one
moves upstream. On average, the Bitou Estuary is more saline than the Keurbooms Estuary,
perhaps because of a combination of the smaller catchment and thus lower volume of
freshwater inflow and longer residence periods due to obstructions to natural flow (see
Section 3.1.2 on emergent macrophytes for contradictory evidence and explanation). Values
upstream of the N2 bridge in the Keurbooms Estuary are generally <15 ppt on the ebb tide,
but this will vary depending on the volume of freshwater inflows. Salinity levels will
generally decrease over winter due to increased freshwater runoff. Tidal exchange occurs
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throughout the systems, but the entire water column is only flushed each spring tidal cycle
below the N2 bridges (CSIR 2007).
The location and extent of the River-Estuarine Interface (REI), defined by brackish waters of
<10 ppt, will vary depending on the volume of freshwater inflows. Based on simulations
(Bitou Municipality 2008), the REI in the Keurbooms Estuary may be located above the
Whisky Creek area when mean monthly flows are < 0.5 m3/s, 10 km from the mouth (0.5 –
1.0 m3/s), 4km from the mouth around Stanley’s Island (1.0 – 10 m
3/s) and right as far as the
mouth region when flows exceed 10 m3/s. In the Bitou Estuary, the REI will be located above
the causeway at flows < 0.5 m3/s, above the top third of the arm (0.5 – 1.0 m
3/s), above the
top two-thirds (1.0 – 10 m3/s) and as far as the mouth region when flows exceed 10 m
3/s
1.
2.4.5 pH
The pH in the systems ranges from 6 to 8.6 with values decreasing upstream in the
Keurbooms Estuary in lower salinities but showing an increase upstream in the Bitou Estuary
(CSIR 2007; James and Harrison 2009), possibly due to photosynthetic activity of extensive
Zostera beds. Riverine water in both systems is slightly acidic due to the leaching of humic
acid (Duvenage and Morant 1984).
2.4.6 DISSOLVED OXYGEN
Dissolved oxygen (DO) values in both estuaries may vary between 0 and 11.8 mg/l
(Duvenage and Morant 1984; Grange 1999), with the lowest values being associated with the
deeper sections. These low concentrations may persist in times of prolonged reduced
freshwater flow, as inflow is responsible for flushing these deeper sections. James and
Harrison (2009) report that DO in surface waters (4.5 to 7.3 mg/l) was generally higher than
in bottom waters (3.0 – 7.4 mg/l), with the Keurbooms Estuary exhibiting a decrease in
values upstream where deeper areas are prone to hypoxia. The reverse was evident in the
Bitou Estuary, once again most probably due to the extensive plant growth.
2.4.7 TURBIDITY
Turbidity is very low, with Secchi disc readings averaging between 1.4 and 1.7 m and only
reduced to < 1 m at times of flooding, reflecting systems that have a dominant marine
influence relative to freshwater inputs.
2.4.8 NUTRIENTS
Keurbooms River Nitrate & Nitrite: 0 – 0.48 mg.l-1
. Ammonia: 0 – 0.71 mg.l-1
(Duvenage
and Morant 1984). Keurbooms Estuary Nitrate: 3.5 – 4.5 mg.l-1
. Inorganic orthophosphate:
River: 0 – 0.16 mg.l-1
; Estuary: 0 – 0.9 mg.l-1
. High nutrient levels could be attributed to the
release of sewage into the Bitou Estuary through the Gansvlei wetland system (Duvenage and
Morant 1984). Snow (2005, unpublished data) recorded the following nutrient levels in the
Keurbooms Estuary during a minor flood in 2002: Total Organic Nitrogen ranged from 23.17
µM in the upper reaches to 3.58 µM in the lower reaches; PO4 ranged from 1.96 µM in the
upper reaches to 2.55 at the confluence with the Bitou Estuary; No detectable concentrations
1 Distances from the mouth are indicated at ebb tide.
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of NH4 was found in the estuary; Silicate ranged from 35.02 in the upper reaches to 81.3 at
the confluence of the Bitou.
The following extract is from the Physical Dynamics Specialist Study for the Rapid Reserve
Determination (CSIR 2007):
Except for measurements taken during March 1987 (in particular those collected from the
‘blind arm’, a then extensive area situated towards the mouth), dissolved inorganic nitrogen
(DIN) concentrations in the Keurbooms Estuary is considered to be relatively low – below
200 µg/ℓ, representative of concentrations measured in the inflowing river and seawater
(NOTE: Total DIN data is not provided for March 1987 as Total ammonia was not recorded
at the time. The above observation is based on the nitrate plus nitrite concentrations). Much
of the catchment consists of Table Mountain Sandstone resulting in relatively little nutrient
enrichment of the river water, while the inorganic nutrient concentrations typically measured
in marine waters off the south coast of South Africa are also generally low. There are also no
major anthropogenic sources of nutrients in the catchment, comprising largely undisturbed
rural areas and limited agriculture development and no large urban or industrial areas.
The high inorganic nitrogen concentrations recorded near the mouth (salinities > 25 ppt)
during March 1987 can only be explained as significant remineralisation/nitrification
occurring within the estuary as Nitrate/Nitrite concentrations in both the sea and river inflow
were much lower. During March 1987 the shallow, ‘blind arm’ comprised a much larger area
than at present and was covered in dense submerged macrophyte beds, providing organic
matter and longer residence time of water for remineralisation/nitrification to show
significant effect. A possible explanation for this phenomenon not being observed in later
surveys is that since 1987 the mouth of the estuary has been migrating towards the west,
significantly reducing the size of the blind arm, thus affecting its potential to contribute to the
inorganic nitrogen budget of the estuary through remineralisation/nitrification.
Although DIN concentrations are relatively low in the Keurbooms Estuary, it does not seem
to become depleted even during periods of lower river inflow, suggesting that the estuary is
fairly well flushed – both through freshwater inflow and tidal exchange - except in the few
deeper pools situated upstream of the N2 in the Keurbooms. Therefore, although DIN inputs
from the river and sea to the estuary may be low, stocks are continuously replenished through
proper flushing – emphasizing the importance of freshwater base flows and maintaining an
open mouth.
Dissolved reactive phosphate (DRP) concentrations in the Keurbooms Estuary are low –
below 50 µg/ℓ. Results showed no specific trend other than reflecting the low concentrations
of the source waters (river: salinity = 0 and sea: salinity = 35).
As for DIN, although DRP concentrations in the Keurbooms Estuary are relatively low,
concentrations do not become depleted. This also supports the suggestion that the Keurbooms
Estuary is still sufficiently flushed - through freshwater base flows and tidal exchange
through the open mouth – to continuously replenish nutrient supplies to the estuary, albeit
low.
As expected the river is a significant source of dissolved reactive silicate (DRS) to the estuary
as reflected in the DRS concentrations increasing with a decrease in salinity (depending upon
catchment characteristics, high DRS concentrations often occur in terrestrial [fluvial] run-off
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- Eagle and Bartlett 1984). Based on the data collected in the Keurbooms River by DWAF
(2007), DRS concentrations in river inflow can vary considerably although no particular
trend was apparent. Concentrations in seawater remained low, but fairly constant.
2.4.9 POLLUTION
Sewage
Treated sewage from the Bitou treatment facility (see Figure 2.2) is discharged in the Bitou
estuary via the Gansvlei and Rietvlei wetland systems at the head of Goose Valley, increasing
the flux of nutrients into the system (Bornman and Adams 2005). As the town and water
demand grows, so will the volume of sewage that needs to be discharged. Fortunately most of
the treated sewage is currently used to irrigate existing golf courses and polo fields and it is
expected that the demand for treated sewage will grow. There is, however a risk of untreated
sewerage entering the system either due to failed infrastructure at the treatment works
(particularly during peak holiday periods) or floods scouring through the treatment works.
Industrial
No industrial activities take place in the catchment of the Keurbooms or Bitou Rivers.
Metals
Samples (water, surface sediment and sediment cores) collected from the Keurbooms and
Bitou Estuaries in July 1978 were analyzed for metals in order to serve as a baseline for
future monitoring surveys (Watling and Watling (1982). Water samples were analyzed for
nine elements (copper, lead, zinc, iron manganese, cobalt, nickel, cadmium and mercury)
while sediment samples were analyzed for 16 elements (same as water, but including sodium,
potassium, calcium, strontium, magnesium, aluminium and chromium).
Concentrations of elements in water samples were considered average for similar
southeastern cape rivers, with the exception of lead and cadmium, which were elevated. No
source could be identified and it is thought they may be of geochemical origin.
Metals in surface sediments were considered average, but on average were slightly elevated
in the Bitou when compared to the Keurbooms, possibly due to mineralisation in the
catchment. Concentrations were elevated in the vicinity of the Plettenberg Bay Angling Club
marina on the Keurbooms, most likely as a result of spills and human activity. The
southwestern arm of the lagoon close to Poortjies and Plettenberg Bay exhibited elevated
levels due to contaminated urban runoff. Metals contained in the surface sediments can be
released or remobilized by flooding or dredging and could potentially alter water chemistry
significantly.
Sediment core samples from the Bitou Estuary support the mineralized catchment hypothesis,
with elevated levels of some metals (leached from the sediment in the catchment) being
detected. Concentrations in the Keurbooms Estuary and the lagoon were considered normal.
Although there are no recent data available on trace metal contamination, similar trends are
expected as those found in 1978 (Watling and Watling 1982). However, the rapid urban
development that has since occurred particularly around the basin area may have elevated the
contamination in this area. There has not been any large urban or industrial development in
either the Bitou or Keurbooms catchments since 1978 that could have resulted in metal
contamination further upstream.
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Mussel tissue (Perna perna) samples collected near the mouth area in 1978 also did not
reveal significantly elevated trace metal concentration (Watling and Watling 1979). However,
rapid urban development that has since occurred in the Plettenberg Bay area may have
changed the situation to some degree.
2.5 FLOODS
2.5.1 FRESHWATER FLOODS
The Keurbooms and Bitou systems are prone to episodic flooding that has catastrophic
consequences for landowners and infrastructure and also poses a risk to human safety.
Floodwaters cause extensive erosion, particularly in the lower reaches where land has been
cleared to make way for residential developments and resorts. The removal of riparian
vegetation weakens the banks’ stability causing it to be undercut and ultimately collapse into
the estuary. This poses a threat to structures (homes) that are built close to the edge and
which may too collapse into the system. In addition, landowners literally lose their property
as it is washed away. Structures such as bridges (old N2 bridge across the Bitou washed away
in 1940), slipways and jetties are severely damaged or washed away and dwellings located
below the floodline are inundated with water. The effects of these floods have been
exacerbated in recent times by the accumulation of debris in the catchment, mostly from
forestry and alien clearing projects. This debris firstly dams the water as it is washed into the
rivers and blocks the channel and then finally releases it when volumes become excessive.
The resultant wall of water then scours down the systems, its destructive force enhanced by
the debris load.
The greatest damage occurs in the Keurbooms system below the N2 bridge, as this is where
the most development has occurred and where vegetation has been cleared (Plate 2.4).
However, most structures adjacent to the estuary, irrespective of their location along its
course are affected to some extent (e.g. CapeNature picnic sites; Plate 2.4). The Bitou
floodplain suffers less direct structural damage to infrastructure and land, but dwellings are
still prone to flooding. The greatest unknown factor is the timing of floods, and with climate
change affecting global weather patterns, this threat may become more frequent and perhaps
more severe.
2.5.2 MARINE (STORM) FLOODS
Flooding from the seaward side during extreme storm events can also cause widespread
damage to property, infrastructure and the banks of the estuary that have been destabilized by
developments. As is the case with freshwater flooding, these events are unpredictable
(frequency and ferocity) and can occur at any time.
2.5.3 RECOMMENDATIONS
The solution to this problem is complex, as most damage occurs to existing structures that
cannot simply be removed from within the threat area. The following recommendations can
be considered:
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• No new developments within the risk area – this could be the 1:100 year floodline or
below the 5 m contour; the latter may be more applicable if a precautionary approach is to
be adopted that will account for climate change.
• Planting of vegetation along the estuary banks where it has been cleared for
developments.
• Clearing of debris from the catchment by forestry and those responsible for alien clearing
projects.
• Bank stabilization to repair existing damage and to minimize impacts from future events.
Attempts to stabilize the banks in the lower reaches of the Keurbooms have met with
varying levels of success (Plate 2.5) and the EMP will attempt to establish a protocol for
best practice based on existing technologies and past successes. In addition, the
authorization process needs to be revisited (with DEADP) to account for landowners
needing to carry out repairs (to banks, jetties and slipways) after each event without
having to undertake the EIA process each time.
Plate 2.4 Flood damage on the Keurbooms in the middle reaches at Forever Resorts (top
left), the lower reaches (top right) and the upper reaches at one of the CapeNature picnic sites
(bottom).
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Plate 2.5 Attempts at bank stabilization in the lower reaches of the Keurbooms Estuary have
met with varying degrees of success.
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CHAPTER 3 – BIOLOGICAL DESCRIPTION
3.1 FLORA
3.1.1 MICROALGAE
Adams et al. (1999) showed that an increase in freshwater input between August and
November 1992 caused a decrease in mean salinity, an increase in the horizontal gradient and
an increase in nitrate (0.3 – 4.4 µM) and chlorophyll-a concentrations (0 – 13.3 µg l-1).
Although Grange (1999) reported that, based on the appearance of filter paper after water had
been passed through it, phytoplankton is of little if any ecological significance in the estuary,
other studies refute this and indicate that freshwater inflow stimulate microalgal growth and
therefore primary productivity. Adams et al. (1999) also reported on the benthic microalgal
biomass that ranged from 106 – 191 mg.m-2 for intertidal sites and 257 to 640 mg.m-2 for
subtidal sites. Compared to other Cape estuaries these values were moderately high. A recent
comparison of benthic microalgal biomass in permanently open estuaries by Snow in 2005
(NMMU; unpublished data) recorded intertidal biomass in the Keurbooms as 9.53 ± 0.78
µg.g-1. This value was lower than most of the other estuaries sampled and was related to the
sandy nature of the estuary and low sediment organic content compared to the other estuaries
included in the analysis.
3.1.2 MACROALGAE
See Figure 3.1 for a fine-scale vegetation distribution map.
Submerged macrophytes
Duvenage and Morant (1984) stated that Zostera capensis is the dominant submerged
macrophyte in the Keurbooms/Bitou system and occurs in both intertidal and subtidal
habitats. More recently, however, Bornman (2004) showed that Ruppia cirrhosa is in fact the
dominant submerged macrophyte in the Bitou Estuary. Although Ruppia has a wide salinity
tolerance range (0-75 ppt), it does not survive in the lower reaches (lagoon area) since it has
relatively weak stems that break in the presence of strong currents. Very little Z. capensis was
found in the Bitou Estuary above the N2 bridge because of reduced tidal action caused by
physical obstructions. Halophila ovalis has also been recorded in the Keurbooms/Bitou
Estuary (Duvenage and Morant 1984).
Emergent macrophytes
In the Keurbooms Estuary, reeds and sedges are limited to the supratidal marshes and areas of
freshwater inflow. The Bitou Estuary is characterized by dense monospecific stands of
Schoenoplectus scirpoides and Phragmites australis within the channel because of the low
flow and restricted tidal action (Bornman 2004). The presence of these species within the
main channel of the Bitou is indicative of relatively low salinities (0 – 25 ppt). This
contradicts the previous statements (see Section 2.3.4 on salinity) that the Bitou Estuary is, on
average, more saline than the Keurbooms. It could be that low flow and increased
evaporation during summer temporarily increases the salinity in the Bitou, but the presence of
the reeds and sedges indicate a fresher state for prolonged periods. Reeds and sedges can
survive tidal inundation with saline water if their roots and rhizomes are located in brackish
water (salinity < 15 ppt). Adams and Bate (1999) showed this for a site in the Keurbooms
lagoon where interstitial water salinity (15-28 ppt) was lower than surface water salinity (34
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ppt). There was a decrease in the height of P. australis with an increase in interstitial water
salinity (112 cm vs 275 cm).
Intertidal saltmarsh
The dominant intertidal salt marsh species in the Keurbooms are Spartina maritima,
Sarcocornia perennis and Sarcocornia decumbens (Duvenage and Morant 1984). Salt
marshes are not extensive in the Keurbooms Estuary due to the geomorphology of the system
(limited space). The Bitou Estuary has a wide floodplain connected to the estuary by
numerous tidal creeks. The largest areas of salt marsh occur on these floodplains. The species
recorded by Bornman (2004) are very similar to those reported in Duvenage and Morant
(1984).
Supratidal saltmarsh
The elevated areas of the floodplains are covered with supratidal salt marsh vegetation,
mainly dense cover of Sarcocornia pillansii (Bornman 2004). The largest supratidal salt
marshes are found on the floodplain of the Bitou Estuary. Saline groundwater encourages the
growth of salt marsh vegetation on the supratidal flats (Reddering and Rust 1994; Bornman
2004). Mats of grasses such as brakgras (Sporobolus virginicus) and seaside quick
(Stenotaphrum secundatum) dominate large sections of the disturbed upper marsh in both the
Bitou and Keurbooms estuaries (Bornman 2004). The fringes of the floodplains are occupied
by reeds, rushes and sedges, e.g. Juncus kraussii, Juncus acutus, Schoenoplectus lacustris,
Phragmites australis and Typha capensis (Bornman 2004). These plants frequent less saline
areas and are normally an indication of freshwater inflow.
Terrestrial plants
The terrestrial vegetation in the middle and lower reaches can be grouped into five types,
namely primary dune scrub, secondary dune scrub, hind dune scrub, fynbos and aliens.
Distribution patterns and composite species may be found in Duvenage and Morant (1984).
The upper reaches are characterized by dense indigenous forest interspersed with alien trees.
Alien tree species, most notably Acacia melanoxylon, Acacia saligna and Acacia mearnsii,
are invading the floodplain areas of the Bitou and Keurbooms Estuaries (Bornman 2004).
Alien infestation is also a problem within the entire catchment/riverine area and alien clearing
programmes are active in dealing with this problem (Plate 3.1).
Plate 3.1 Clearing and stand of Alien Poplar (Populus sp.) trees alongside the Bitou River
just above the upper reaches of the estuary.
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Figure 3.1 Vegetation and habitat map of the Bitou Estuary and the lower and middle reaches
of the Keurbooms Lagoon and Estuary (Bornman and Adams 2007).
3.1.3 THE BITOU FLOODPLAIN/WETLAND COMPLEX
(From Allanson Grange Associates 1997; Eden to Addo 2010).
The Bitou wetlands located between the N2 road/bridge and the Bosfontein River are one of
the last undeveloped floodplains along the Western Cape coast and comprise a series of
typical open freshwater marsh systems (Gansevlei and Rietvlei), supra- and inter-tidal
saltmarsh, river channels (Diep River) and the Bitou Estuary channel itself. Floods are
episodic, usually occurring in spring/early summer and are vital for maintaining ecosystem
functioning in combination with the twice-daily tidal cycles (AGA 1997). According to
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Haigh (2005), the Bitou wetlands are the most valuable ecological resource of the entire
catchment, and are currently under severe threat of development on its perimeter. The
wetland corridor provides a link between the SANParks Forest Reserve and the Keurbooms
Nature Reserve and potentially allows for the movement of species (and therefore genetic
material) between protected areas.
Floodplain saltmarsh areas are dominated by Sarcocornia perennis while riparian areas
comprise mostly reeds (Phragmites australis) and sedge (Scirpus littoralis). Upstream of the
causeway, the riparian vegetation comprises indigenous milkwoods and some yellowwoods.
The floodplain in the upper reaches also comprises scattered concentrations of rush (Juncus
kraussii). The terrestrial portion of the Bitou Valley comprises fynbos associated species,
Valley Thicket and Knysna Afromontane Forest. Commercial forestry and alien species are
the biggest threats in the catchment. Numerous shallow open pans are scattered on the
floodplain and are considered an important habitat for birds.
Levels of phosphate appear to be low in the wetlands, indicating that the system is not
polluted from contaminated agricultural return flows enriched by phosphate-based fertilizers.
Riverine health is considered to be good based on certain indicator species such as
dragonflies.
The Rietvlei wetland system is a complex of seasonal and permanent vegetation including S.
littoralis, Bulboschoenus maritimus, Typhus sp. and aquatic grasses. Baillon’s crake, which is
a Red Data species, is known to breed here and other rare birds such as the redchested
flufftail, African rail, black crake, purple gallinule and purple heron are common residents.
Areas characterized by temporary pools and short grasses are dominated by small waders,
ducks, spoonbills and ibis.
Large areas of the floodplain are used for grazing cattle, but this is not intensive, and
vegetation cover and riparian cover are maintained so that erosion and bank destabilization
(also from trampling) is not a concern. Cows access the water to drink when it is not too
saline. There are several access roads through the floodplain on private property and although
it is unknown whether these have an adverse affect, it is unlikely as they do not block
drainage channels and still allow free movement of water (Personal Observations and
anecdotal information from landowners).
The Gansvlei/Diep River/Rietvlei system of rivers and wetlands serve to filter and further
purify the treated effluent from the Bitou Sewerage Works located at the head of Gansvalei
(this feeds into the Gansvlei). The maintenance of these wetlands as a buffer is important if
water quality entering the Bitou Estuary is to be maintained at an acceptable level.
The major concern emanating from the AGA (1997) study was if the floodplain area was to
be used more intensively from an agricultural point of view. This does not appear to have
happened, although the impact of additional developments adjacent to the Rietvlei (polo
fields and industrial park) and ineffective culverts (too small or blocked) where roads cross
the system need to be determined.
Although the AGA (1997) report recommended that the portions of land comprising the
wetland floodplain system be transferred to a Trust and established as a conservancy, this
never came to fruition, despite support from a range of landowners. The land on the northern
side is currently still being used for grazing and does not appear to have been severely
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degraded. Meetings with current landowners revealed that they feel they look after the area
already and do not need a conservancy to facilitate a management function they already
fulfill. A recommendation may be to fence off sensitive areas to prevent damage to
vegetation by grazing and trampling, but this will need to be done in cooperation with the
private landowners. In addition, the Eden to Addo initiative (2010; building on AGA 1997) to
establish the Bitou Corridor linking the SANParks and Keurbooms protected areas needs to
be considered in cooperation with landowners.
3.2 FAUNA
A comprehensive list of faunal species that are found or are likely to be found within and in
association with the Keurbooms and Bitou Estuaries is available in Duvenage and Morant
(1984). These lists will not be reproduced here, but key species will be referred to in the
relevant sections.
Zooplankton
Zooplankton displays high species richness in the Keurbooms Estuary, with 39 species being
recorded and a dry biomass of between 2.9 to 108 mg/m3 (Duvenage and Morant 1984).
Pseudodiaptomus hessei is the dominant copepod and is particularly abundant in lower
salinity waters above the N2 bridge in the Keurbooms. A more recent survey by Grange
(1999) reported low biomass of zooplankton.
Benthic invertebrates
Hard (rocky) substrates are scarce in the Keurbooms / Bitou Estuary and as a result there are
limited fauna present that require these habitats. The largest proportion (42 taxa) of the
invertebrate fauna is either benthic or associated with the aquatic vegetation (Duvenage and
Morant 1984; Zoutendyk and Bickerton 1999). The benthic fauna is well developed from the
lower reaches (lagoon) to the middle reaches, with sandparwn (Callianassa kraussi) in sandy
areas, bloodworm (Arenicola loveni) and pencilbait (Solen capensis) in muddy sand and
mudprawn (Upogebia africana) abundant in sandy mud (Day 1981; Grange 1999). The
bivalve Donax spp. (sand mussel) and the echinoids Echinodiscus bisperforatus (pansy shell)
and Echinocardium sp. also burrow the sand in the area proximal to the mouth (Reddering
and Rust 1994). Solen spp. and Arenicola loveni burrow into the sediment of the intertidal
flats (between neap high tide and subtidal levels) and have a limited distribution upstream of
the Keurbooms/Bitou confluence (Duvenage and Morant 1984; Reddering and Rust 1994).
The distal tidal flats are occupied by the prawns C. kraussi, U. africana and the cracker
shrimp (Alpheus crassimanus). The largest and most closely spaced U. africana population
occurs in the Bitou Estuary, where muddier sediments are present (Duvenage and Morant
1984; Reddering and Rust 1994). Their populations are threatened in the system through the
incursion of marine sand and exploitation for bait. Cracker shrimp burrows in the Zostera
covered intertidal areas where the currents are slower. Macro-invertebrates such as
Nassarius, Natica and Diogenes are common on the mid and distal flat areas while the mud
crab (Scylla serrata) is common amongst saltmarsh vegetation and Zostera beds. An
abundance of crabs, either Sesarme castenata or Cleistostoma edwardsii were observed
amongst the mud and creek vegetation of Gansvlei during a recent fieldtrip (Aidan Wood,
Pers. Obs.). Intertidal macro-benthos standing stock (as carbon) ranged from < 10 gC.m-2 in
sand to 100 gC.m-2 in muddy sediments (Zoutendyk and Bickerton 1999). Mudprawn and
sandprawn together contributed more than 50% (26 tonnes) of the standing stock of benthos
carbon in the Keurbooms Estuary.
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An important component of the soft sediment community is the pansy shell or sand dollar, an
Indo-Pacific species of the family Astriclypeidae, which lives in the upper 5 cm of sediment.
The species inhabits sandy intertidal and subtidal areas to depths of approximately 20 m. Of
the three main populations of E. bisperforatus in South Africa, two are within Plettenberg
Bay. One of these is located along Keurboomsstrand and in the lagoon in the vicinity of the
mouth near the caravan park. The limited distribution and high souvenir value have resulted
in the species being classified as endangered in South Africa, and protected by the Sea
Fisheries Act (Act 82 of 1973) (Bentley and Cockroft 1994).
Amphibians and reptiles
Fourteen amphibian species are likely to be associated with the Keurbooms and Bitou
systems, but only two of these have actually been recorded, namely Heleophryne regis and
Rana fasciata (Duvenage and Morant 1984).
Twenty-seven snake species are likely to be associated with the Keurbooms and Bitou
systems, but only two of these have actually been recorded, namely Lycodonomorphus
rufulus and Bitis atropos.
Three species of tortoise and one species of terrapin are likely to be associated with the
systems, but none have been recorded in the literature.
Freshwater fish
The Keurbooms redfin (Pseudobarbus cf. tenuis) is an endangered species found in the
Kransbos, Diep and Langbos rivers of the catchment and has been identified as requiring
special conservation attention (CapeNature 2007). It has been assigned a high priority, which
means there are less than three populations left and is under severe risk of extinction. In
addition, the following indigenous species are known to occur (Skelton 1994; Russell 2002);
forest redfin (Pseudobarbus afer), Cape galaxias (Galaxias zebratus), Cape kurper (Sandelia
capensis) and longfin eel (Anguilla mossambica). Alien species include rainbow trout
(Onchorynchus mykiss), brown trout (Salmo trutta) and large-mouth bass (Micropterus
salmoides). Two marine-migrant species, namely Cape moony (Monodactylus falciformis)
and freshwater mullet (Myxus capensis) have been found in the riverine region above the
estuary. Interestingly, G. zebratus is represented by its most eastern distribution in the Bitou
River and is not found in the Keurbooms arm of the system (Skelton 1994).
Marine and estuarine fish
The fish fauna of the Keurbooms and Bitou were sampled by multi-mesh gillnets and seine
nets in November 1994 (James and Harrison 2009). A total of 23 species representing 13
families were caught, with the Mugilidae (5 species), Sparidae (4 species) and Gobiidae (4
species) dominating the catch. The Cape stumpnose (Rhabdosargus holubi) was numerically
dominant (46.4% of total catch and mostly newly recruited juveniles) followed by juvenile
mullet (27.5%). Dusky kob (Argyrosomus japonicus) dominated the catch in terms of
biomass (31.1%) followed by the mullet Liza richardsonii (29.2%). The Knysna seahorse
was not recorded during their survey, but Whitfield (1994) reports that it does occur together
with 28 other species (see below). Both reports also include the longsnout pipefish
Syngnathus temminckii2. Both studies report that the fish fauna is dominated by marine-
migrant species (utilize estuaries but spawn at sea), with a large juvenile component mostly
2 Species name outdated – is now designated Syngnathus acus
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occurring below the N2 bridges, reflecting the importance of these systems as a nursery area
(typical of permanently open estuaries).
In addition to A. japonicus, both systems are home to other important and over-exploited
linefish species such as white steenbras (Lithognathus lithognathus), spotted grunter
(Pomadasys commersonnii) and leervis (Lichia amia). The baardman (Umbrina canariensis),
a marine species is also found in the system and is caught quite regularly. Historical records
show some interesting distributions with Priacanthus hamrur (crescent-tail bigeye, a mostly
sub-tropical to tropical marine species), Trachinocephalus myops (a lizardfish rarely found in
the area) and Stromateus fiatola (blue butterfish; marine species usually found in deeper
waters).
Knysna seahorse
Knysna seahorse (Hippocampus capensis) is the only fully estuarine species and its
distribution amongst aquatic vegetation, has been confirmed historically in only four SA
estuaries, namely Knysna, Swartvlei, Keurbooms/Bitou and Klein Brak (Bell et al. 2003).
However, recent evidence suggests it no longer occurs in the Klein Brak (Teske et al. 2003;
Lockyear et al. 2006). The species does not appear to show a preference for a specific type of
vegetation and is found in association with Zostera capensis, Caulerpa filiformis, Codium
extricatum, Halophila ovalis and Ruppia cirrhosa (Teske et al. 2007). It does however appear
to prefer areas where vegetation cover exceeds 75% and any conservation efforts should
concentrate in sections of the estuary where vegetation cover is high. A survey by Bell et al.
(2003) failed to locate any in the Keurbooms or Bitou estuaries in 29 (30 x 2 m) transects
(total of 12 man hours underwater). However, surveys (at 41 sites) conducted in March/April
of 2002 and 2003 (Lockyear et al. 2006) revealed a density of 0.28/m2 (total number 102) in
2002 but zero in 2003 (possibly due to being washed out by flood waters). Estimates of total
population size in 2002 were 836 298, with the highest density (6/m2) being recorded at the
Bitou/Keurbooms confluence. It is listed as an Endangered species on the International Union
for Conservation of Nature (IUCN) Red List due to its fragmented distribution, small area of
occupancy, the vulnerability of its habitat and susceptibility to high mortality due to
freshwater flooding (Russell 1994). Analysis of mitochondrial DNA sequences suggest that
although the species originated in the Knysna Estuary as much as 486 000 years ago, the
three extant populations are now thought to be distinct, i.e. they do not mix and can thus be
regarded as separate management units (Teske et al. 2003). However, Lockyear et al. (2006)
do propose a hypothesis that the Knysna population may be the source of new colonists for
the Keurbooms after flood events and that the system is merely a temporary habitat for the
species at times when conditions are favorable. Research is urgently required to determine
whether the Keurbooms population is permanent.
Birds
Acknowledgement
Much of the following information has been gleaned from the Coordinated Waterbird Counts
(CWAC) for the Keurbooms River Estuary (Site Code 34022324) between July 1997 and
July 2009. CWAC data were obtained from the Animal Demography Unit, University of
Cape Town. The owner of the data is Mr Brian Denman.
A total of 64 species, totaling 31 051 individuals have been recorded over the 13 year period.
The kelp gull is by far the most dominant species with 9 183 birds being counted, followed
by the swift (great crested) tern (4 953), grey plover (1932), reed cormorant (1 850), curlew
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sandpiper (1 586), sacred ibis (1 200) and common whimbrel (1 070). Two pursuit-swimming
piscivores, namely the white-breasted cormorant and the Cape cormorant, which are capable
of feeding on up to 16% of their body weight daily, numbered 588 and 462 respectively. A
total of 503 of the endangered African black oystercatcher were counted. Some species were
only counted once or twice and represented by less than 10 individuals, e.g. black-headed
heron (6), Cape shoveler (2), common moorhen (1), great crested grebe (2) and red-knobbed
coot (1). A full list with total numbers is provided in Appendix 1.
The most birds were counted in January 1997, with 2 072 individuals being recorded,
followed by January 1996 (1 695), February 2002 (1 569), January 2005 (1 519) and July
1996 (1 365). In the last year, a total of 1 133 birds were counted in February 2009 and 821 in
July 2009 (Appendix 1). Counts over summer months always exceed those in winter of the
same year due to the influx of summer migrants. In summer the avifauna is dominated by
migratory waders (41%), gulls (mainly Kelp Gull; 29%) and terns (mainly Swift Terns;
15%). The remaining avifauna includes a variety of wading birds (particularly Sacred Ibis
and Reed Cormorant; 8%), resident waders, cormorants and small numbers of waterfowl. In
winter, numbers are dominated by terns (26%) and gulls (21%) and wading birds
(particularly Reed Cormorant and Sacred Ibis; 15%). Resident waders (13%) and migratory
waders (immature over wintering birds; 9%), cormorants (9%) and waterfowl (6%) make up
most of the remainder. About 12% of migratory waders remain in winter. Cormorants and
waterfowl are about three times more abundant in winter than summer, and resident waders
are twice as abundant. Wading birds, kingfishers and terns occur in roughly equal numbers
in summer and winter, but gulls are fewer in winter (italics referenced from Bitou
Municipality 2008).
A report based on CWAC counts between 1992 and 1997 stated that bird species numbers
and total counts for the Bitou Estuary had been on the decrease and this was attributed to
pollution from effluent, pesticides and fertilizers, damage to habitat by livestock, siltation of
the estuary, reed encroachment and residential development (Taylor et al. 1999). An example
is the significant decrease (and sometimes absence) in the two flamingo species. Bird
numbers in the Keurbooms Estuary are threatened by residential development, boating,
fishing, domestic animals and bank erosion, which all contribute to habitat destruction and
disturbance.
The lower Bitou River includes excellent marsh habitat for rails and other secretive birds, and
redchested flufftail and Baillon's crake may breed in this area. Moorhen counts peak in winter
although recorded numbers are decreasing; winter Dabchick counts are also decreasing. The
area is important for foraging and roosting shorebirds, waterfowl and egrets. The Bitou
wetlands system is considered vital from a bird (breeding and biodiversity) point of view and
is need of protection (Haigh 2005).
The following information has not been sourced from the CWAC data:
The bird sanctuary located at the Keurbooms mouth has the largest breeding colony of kelp
gulls in the region, with approximately 1450 breeding pairs recorded in 2003 (Whittington
2004). In addition, the African black oystercatcher and several tern species are also thought to
breed and roost within the sanctuary.
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Mammals
Common mammals that may be spotted within the Keurbooms Nature Reserve and in close
association with the estuaries include the bushpig, dassie, caracal, genet, baboon, vervet
monkey, blue duiker, bushbuck, grysbok, leopard, mongoose and the Cape clawless otter.
(http://www.capenature.org.za/reserves.htm?reserve=Keurbooms+River+Nature+Reserve#re
serve_tabs).
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CHAPTER 4 – LEGISLATION AND PLANNING &
DEVELOPMENT STRATEGIES
The purpose of this section is to review all forms of legislation that may have an impact on
the management of the Keurbooms and Bitou Estuaries. This review incorporates
international agreements and strategies as well as all forms of national, regional and local
legislation as well as municipal planning and development strategies.
4.1 INTERNATIONAL OBLIGATIONS (Table 4.1)
Table 4.1 Summary of International obligations and their relevance to estuarine management.
4.2 NATIONAL LEGISLATION (Table 4.2) AND POLICY (Table 4.3)
International Obligations Short Description
Convention on Wetlands of International
Importance especially as Waterfowl Habitat
(1971) (Ramsar Convention)
The broad aims of this Convention are to stem the loss and to promote wise use of all
wetlands (including estuaries).
Agenda 21 (1992) as reaffirmed at the United
Nations World Summit on Sustainable
Development - Johannesburg Summit (2002)
This is not a legally binding document, but Agenda 21 is an internationally accepted
strategy for sustainable development; the principles of sustainable development are
easily applied to the estuarine scenario.
United Nations Convention on Biological
Diversity (1992)
The objectives of convention include the conservation of biological diversity; the
sustainable use of biological resources; and the fair and equitable sharing of benefits
arising from the use of genetic resources.
United Nations Framework Convention on
Climate Change (1992)
This framework sets an "ultimate objective" of stabilizing greenhouse gas
concentrations in the atmosphere at a level that would prevent dangerous
anthropogenic interference with the climate system. This has particular relevance to
estuaries when considering changes in rainfall, storm severity and flood levels and
frequencies.
Global Programme of Action for the Protection
of the Marine Environment from Land-based
Activities (GPA) (1995)
The GPA is designed to assist states in taking action to prevent, reduce, control or
elimination the degradation of the marine environment (including estuaries), and to
assist in its recovery or rehabilitation from the impacts of land-based activities.
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Table 4.2 Summary of national legislation and its relevance to estuarine management
(from Taljaard 2007).
National Legislation Lead Agent Short Description
National Environmental
Management: Biodiversity
Act (Act 10 of 2004)
DEA This Act provides for the conservation of biological diversity, regulates the sustainable
use of biological resources and ensures a fair and equitable sharing of the benefits
arising from the use of genetic resources.
National Health Act (No.
61 of 2004)
Delegated to Provincial and
Local authorities from
Department of Health
Delegated to Provincial and Local authorities from Department of Health
National Environmental
Management: Protected
Areas Act (Act 57 of
2003)
DEA This Act provides for the protection and conservation of ecologically viable areas
representative of South Africa’s biological diversity and its natural landscapes and
seascapes; for the establishment of a national register of all national, provincial and
local protected areas; for the management of those areas in accordance with
national norms and standards; for intergovernmental co-operation and public
consultation in matters concerning protected areas.
Disaster Management Act
(No. 57 of 2002)
Act is administered by a
Cabinet member designated
by the President
To provide for an integrated and coordinated disaster management policy that
focuses on preventing or reducing the risk of disasters, mitigating the severity of
disasters, emergency preparedness, rapid and effective response to disasters and
post-disaster recovery; the establishment of national, provincial and municipal
disaster management centers; disaster management volunteers; and matters
incidental thereto.
Local Government:
Municipal Systems Act
(Act 32 of 2000)
Department of Provincial and
Local Government
This Act deals with Integrated Development Planning (IDP), which is intended to
encompass and harmonize planning over a range of sectors such as water, transport,
land use and environmental management.
Development Facilitation
Act (Act 67 of 1995)
Same This Act requires the setting of Land Development Objectives and the principles of
this Act have also been incorporated into the Municipal Systems Act.
Local Government
Transition Second
Amendment Act (Act 97
of 1996)
Same This Act requires that all municipalities, local and district councils, draw up IDPs for
the integrated development and management of their areas of jurisdiction.
Local Government
Municipal Structures Act
(No. 117 of 1998,
amended by Act 33 of
2000)
Same This Act provides for “the establishment of municipalities in accordance with the
requirements relating to categories and types of municipality; to establish criteria for
determining the category of municipality in an area” and other related matters.
National Environmental
Management Act (Act 107
of 1998)
DEA and provincial DEADP This Act provides for the conservation of biological diversity, regulates the sustainable
use of biological resources and to ensures a fair and equitable sharing of the benefits
arising from the use of genetic resources.
National Environmental
Management: Integrated
Coastal Management Act
(Act 28 of 2008)
DEA (Marine & Coastal
Management)
This Act aims to establish a system of integrated coastal and estuarine management
in South Africa, including norms, standards and policies, to promote the conservation
of the coastal environment, the ecological sustainable development of the coastal
zone, to define rights and duties in relation to coastal areas, to determine responsible
organs of state in relation to coastal areas and to give effect to South Africa’s
international obligations in relation to coastal matters and to provide for related
matters.
National Veld and Forest
Fire Act (No. 101 of 1998)
DWA Sets out to reform the law on veld and forest and provides for matters relating to fire
protection, and fighting, offences and penalties and enforcement.
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National Legislation Lead Agent Short Description
National Water Act (Act
36 of 1998)
DWA This Act ensures protection of the aquatic ecosystems of water resources, including
estuaries. It requires policies to be in place that provide guidance in developing
resource quality objectives, i.e. specifying aspects such as freshwater inflow, water
quality, habitat integrity, biotic composition and functioning requirements.
National Forests Act (No.
84 of 1998)
DWA This Act recognizes that natural forests and woodlands (including riparian vegetation)
form an important part of the environment, and need to be conserved and developed
according to the principles of sustainable management.
Marine Living Resources
Act (Act 18 of 1998)
DEA (MCM) This Act deals with the utilization, conservation and management of marine living
resources, the need to protect whole ecosystems, preserve marine biodiversity and
minimize marine pollution as well as to comply with international law and agreements
and to restructure the fishing industry.
Water Services Act (No.
108 of 1997)
DWA Right of access to basic water supply and sanitation; control of water services;
preparation of WSDPs.
The Constitution (Act 108
of 1996)
National Government The Constitution is the supreme law of the land and provides the legal framework for
legislation regulating environmental management in general. The most pertinent
fundamental right in the context of estuarine management is the Environmental Right
which provides that, "Everyone has the right: to an environment that is not harmful to
their health or well-being; and to have the environment protected, for the benefit of
present and future generations through reasonable legislative and other measures
that – prevent pollution and ecological degradation; promote conservation; and
secure ecologically sustainable development and use of natural resources while
promoting justifiable economic and social development.
Local Government
Transition Second
Amendment Act (Act 97
of 1996)
Department of Provincial and
Local Government
This Act also requires that all municipalities, local and district councils, draw up IDPs
for the integrated development and management of their areas of jurisdiction.
Tourism Act (No. 72 of
1993, as amended in
1996 & 2000)
DEA No details.
Development Facilitation
Act (Act 67 of 1995)
Department of Provincial and
Local Government
This Act requires the setting of Land Development Objectives and the principles of
this Act have also been incorporated into the Municipal Systems Act.
Local Government
Transition Act (No. 209 of
1993)
Department of Provincial and
Local Government
To provide for revised interim measures with a view to promoting the restructuring of
local government, and to provide for the establishment of Provincial Committees for
Local Government in respect of the various provinces.
Environmental
Conservation Act (No. 73
of 1989)
DEA Although many of the provisions of this Act have been repealed by NEMA, the
regulation on Sensitive Coastal Areas remains in force until replaced with new
regulations.
Sea Fishery Act 12 of
1988
DEA (Marine & Coastal
management)
This act includes estuaries and the estuary bed and has been used to proclaim
marine reserves along certain sections of our coast.
Conservation of
Agricultural Resources
Act (No. 43 of 1983)
Department of Agriculture This Act provides for the conservation of the natural agricultural resources of the
Republic by the maintenance of the production potential of land, by the combating
and prevention of erosion and weakening or destruction of the water sources
(including estuaries), and by the protection of the vegetation and the combating of
weeds and invader plants.
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Table 4.2 continued
National Legislation Lead Agent Short Description
Marine Pollution (Control
and Civil Liability) Act (No.
6 of 1981)
Department of Transport
(prevention) and DEA
(combating)
This Act provides for the protection of the marine environment from pollution by oil
and other harmful substances, the prevention and combating of such pollution.
National Parks Act (No.
57 of 1976)
DEA; SANP The National Parks Act provides for the establishment of National Parks. National
Park status establishes the strongest claim to permanent protection that is possible.
Areas above and below the intertidal zone may be included in a National Park.
Lake Areas Development
Act (No. 39 of 1975)
DWA This law (rarely used since enactment) provides for the establishment of Lake Areas
(which includes estuaries). The effectiveness of this law is questionable, as only two
such areas have been proclaimed under it. Those Lake Areas are managed by the
SANP by virtue of provisions in the National Parks Act
Sea Bird and Seal
Protection Act (No. 46 of
1973)
DEA (MCM) This Acts governs the protection and control of the capture, killing and products
produced from seabirds and seals.
Hazardous Substances
Act (No. 15 of 1973
Department of Health and
Welfare
To provide for the control (including the prevention of dumping) of substances which
may cause injury or ill health to, or DEAh, of human beings by reason of their toxic,
corrosive, irritant, strongly sensitizing or flammable nature.
Physical Planning Act
(No. 88 of 1967)
Department of Provincial and
Local Government
The Act provides for Guide Plans that could influence the planning and location of
storm water drains.
Seashore Act (No. 21 of
1935)
DEA/Cape Nature This Act provides that ownership of the seashore (which includes the water and land
between the low-water mark and the high-water mark in estuaries and the sea is
vested in the State. This Act still applies to certain aspects until such time as all
sections in the ICMA are enacted.
Marine Notice 16 of
2006[1]
SAMSA Dictates SAMSA policy on small vessel surveys, certification and numbering, and
skipper qualification and certification terms of the Merchant Shipping (Small Vessel
Safety) Regulations of 2002 (as amended).
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Table 4.3 Summary of national policies (white papers) relevant to estuarine management
(from Taljaard 2007).
White Paper Year Short Description
White Paper for Sustainable
Coastal Development in South
Africa
2000 This paper sets out a policy which aims to achieve sustainable coastal development in South
Africa through integrated coastal management. The key messages of the white paper are: 1) the
value of the coast must be recognized, 2) sustainable coastal management must be facilitated;
3) the Coastal management must be co-coordinated and integrated; 4) the Government must
adopt a co-operative style of management.
White Paper on a National Water
Policy for South Africa
1997 This paper sets out the policy for the management of both quality and quantity of South Africa’s
water resources (including estuaries). The National Water Act (No. 36 of 1998) gives legal
status to this White Paper.
White Paper on Marine Fisheries
Policy for South Africa
1997 The White Paper sets out the main policy principles that the Department of environmental
Affairs and Tourism will endeavor to implement through its marine fisheries management
institutions in order to achieve this overall policy objective. The objective is to improve the overall
contribution of the fishing industry to the South Africa’s economy. The Marine Living
Resources Act (No. 18 of 1998) gives legal status to this White Paper.
White Paper on Environmental
Management Policy
1998 The White Paper contains the government’s environmental management policy and includes an
introduction that sets out the concept of environment used in the policy, the scope and purpose
of the policy, new vision for environmental policy and the mission of the DEA with respect to the
new policy, policy principles that must be applied in developing and testing policy, government's
strategic goals and supporting objectives to begin sustainable use of resources, government's
approach to governance, setting out the powers and responsibilities of the different spheres and
agencies of government and the regulatory approach to environmental management. The
National Environmental Management Act (No. 107 of 1998) gives legal status to this White
Paper.
White Paper on Spatial Planning
and Land-use Management
2001 This White Paper addresses the development of policies, which will result in the best use and
sustainable management of land, improvement and strengthening planning, management,
monitoring and evaluation, strengthening institutions and coordinating mechanisms, creation of
mechanisms to facilitate satisfaction of the needs and objectives of communities and people at
local level. Sustainable land management plans should ensure that development and
developmental programmes are holistic and comprehensive, all activities and inputs are
integrated and coordinated, all actions are based on a clear understanding of the natural and
legitimate objectives and needs of individual land users to obtain maximum consensus and
institutional structures are put in place to develop debate and carry out proposals.
White Paper on Integrated
Pollution and Waste
Management for South Africa
2002 This paper outlines a management approach that envisages pollution prevention, waste
minimization, managing the environmental impacts associated with waste and pollution,
remediating damaged environments and integrating the management of various sources of
waste. The white paper proposes a number of tools to implement the objectives, including a
legislative programme that will culminate in new pollution and waste legislation. A National
Waste Management Strategy, which will form the basis for translating the goals and objectives
of this policy into practice, has also been developed. The National Environmental
Management: Waste Management Bill will give legal status to this White Paper.
White Paper on Development
and Promotion of Tourism in
South Africa
1996 The White Paper provides the government’s stance on Tourism and describes the following:
Role of tourism in South Africa; problems around tourism; way towards a new tourism; vision,
objectives and principles; how to ignite tourism growth; roles of key players; and organizational
structures. Based on an assessment of the
problems, constraints and opportunities facing the South African tourism industry, the concept of
"Responsible Tourism" emerged as the most appropriate concept for the development of
tourism in South Africa.
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Table 4.3 continued
4.3 LOCAL (MUNICIPAL) LEGISLATION
There are currently no municipal bylaws (a fact recognized by the Bitou IDP) governing
activities on the Keurbooms or Bitou estuaries and as such there is no legal framework
within which to enforce standards and behaviour. This includes boat registration
procedures and the wake-free zones that are indicated on the estuaries – although most
boaters conform to these restrictions, those that do not cannot be charged or fined. This
needs to be rectified as a matter of urgency and draft bylaws need to be developed and
made available for public comment. Once approved, they will be enacted under the
provisions of Section 156 of the Constitution of the Republic of South Africa. In addition,
according to Chapter 6 (Section 50) of the ICMA, municipal bylaws may include
provisions for the implementation, administration and enforcement of the municipal
coastal management programme (see Section 4.4.4). Until such time as this can be
accomplished, Eden District is investigating the feasibility of instituting their generic
bylaws for public amenities3.
Enforcement of the municipal bylaws is usually the responsibility of either
Environmental Services or Community Protection within the municipal structures.
However, it is likely that this responsibility will be devolved to CapeNature who already
3 The existing Bitou Municipality Public Ameneties By-Law does not make provision for estuaries.
White Paper Year Short Description
White Paper on the Conservation
and Sustainable Use of South
Africa’s Biological Diversity
1998 South Africa's initial response to addressing the United Nations Convention on Biological
Diversity; it specifically recognizes the importance of estuaries and commits the government to a
number of strategies to protect these areas. The strategies suggested cut across a number of
legislative sectors such as water law, resource conservation and planning. These include:
facilitating the development of appropriate legislation to secure the conservation of South
Africa’s wetlands, and to maintain their ecological and socio-economic function, promoting the
establishment of a National System of Protected Wetlands, preventing inappropriate activities
and development around wetlands, ensuring that adequate buffer strips are retained around
wetlands, recognizing the functions and values of wetlands in resource planning, management
and decision-making, determining the impact of commercial, recreational and subsistence
fishery practices on fisheries, fish, and their habitats, and develop guidelines for managing such
fisheries. The National Environmental Management Act (No. 107 of 1998) gives legal status to
this White Paper
Policy on Sustainable Forest
Development in SA
1997 This paper provides synergy to the three strains of Indigenous Forest Management, Commercial
Forestry and Community Forestry. Elements of the policy include: setting nine guiding principles,
future goals and overall policy to govern the place of forestry in the management of land, water,
and other natural resources. This paper provides policy for: industrial forestry; community
forestry; the conservation of our natural forests and woodland; South Africa's response to global
concerns about forests; research, education and training; South Africa's relationships with states
in the Southern African Development Community.
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have the infrastructure in place (manpower and boats) to perform this function (albeit
without enforceable bylaws at present).
The Keurbooms Estuary above the N2 bridge falls within the Keurbooms Nature Reserve
and all aspects are controlled (administered) by CapeNature. This will include aspects
usually controlled by municipal bylaws such as wake free zones and boat registration.
4.4 EXISTING MANAGEMENT PLANS, DEVELOPMENT
STRATEGIES, POLICIES AND CONSERVATION INITIATIVES.
4.4.1 BITOU INTEGRATED DEVELOPMENT PLAN (2008/2009 REVIEW)
In terms of the Municipal Systems Act (Act 32 of 2000), all municipalities have to
undertake an Integrated Development Plan (IDP) process to produce five year IDPs with
legal status that supercedes all other plans that guide development at Local Government
level. The Integrated Development plan (IDP) is the key strategic plan of the municipality
and as such prioritizes projects and determines financial planning and budgets for these
projects. The EMP will need to be incorporated into the IDP so that Management Actions
Plans (MAPs) that require financial input from the municipality can be recognized and be
allocated the necessary funding.
Estuaries are not referred to at all in the IDP and nor is the Bitou River. The Keurbooms
River is only referred to in the context of being the main surface water source for
supplying the municipal demand until 2025, at which stage abstraction could be in the
region of 14.58 Ml/day. Clearly estuaries are not a priority, and the natural environment
does not feature extensively in the IDP’s main strategies, which are:
• Economic development
• Community development, social services and housing
• Spatial development
• Basic services and infrastructure development
• Financial viability
• Good governance
• Transformation and institutional development.
The only specific reference to the natural environment is under basic services and
infrastructure, where it is stated that in ensuring an adequate potable water supply to the
people of Bitou, the rivers must be monitored to ensure sufficient water levels for
ecological conservation. One must assume this includes estuaries and that it refers to the
implementation of the Ecological Reserve.
The following environmental priorities are, however, recognized:
• Natural endowment – Keurbooms is a major supply of surface water; pollution, alien
vegetation and climate change (affecting development) are challenges.
• Pollution – CO2 emissions from tourists contribute to climate change.
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• Conservation – Bitou is home to a diverse range of plants and animals (the ocean and
rivers are mentioned but not estuaries); water conservation and poaching are
challenges.
• Waste management – capacity of landfill site is not sufficient, particularly over
holiday periods.
• Alien plants – consume vast amounts of groundwater and this can lead to shortages
for human consumption (no mention of impact in freshwater inflow and ecological
reserve requirements).
• Deforestation – reduced levels of O2 emissions contribute to climate change (no
mention of erosion and sediment loads in freshwater inflows).
Under economic development, tourism has been allocated a budget in excess of R4
million for the 2010/2011 year, of which R800 thousand is for marketing Bitou as a
tourist destination. The EMP will highlight the need for marketing the Keurbooms and
Bitou Estuaries as tourist destinations.
A SWOT analysis recognizes the opportunity provided by the forests around Bitou for
the timber and furniture industries, alien clearing (job creation) and conservation. Climate
change is viewed as a threat to human safety and sustainable development.
In a summary table in Section 6.7, the IDP states under the heading of environmental
programmes, that there is no plan or funds allocated for this. This is not encouraging
given that much of the local economy relies on the attraction that the unspoilt
environment has to visitors.
4.4.2 BITOU LOCAL MUNICIPALITY SPATIAL DEVELOPMENT
FRAMEWORK (2005)
The Spatial Development Framework (SDF) is prepared, approved and implemented
within the legislative context of the Local Government : Municipal Systems Act, 2000
(Act 32 of 2000) and the subsequent Local Government : Municipal Planning and
Performance Management Regulations (Section 4), 2001 promulgated under Section 120
of the Local Government : Municipal Systems Act, and the Western Cape Planning and
Development Act (Act 7 of 1999).
The SDF indicates, in relation to a relevant, or future, IDP, the spatial implications of the
IDP, and spatially reflects the integration of the various strategies of the IDP; and ensures
sustainability. The SDF further gives effect to Council’s vision for development (spatial
planning) and Council’s objectives and strategies with respect to land development, use
and management. The SDF needs to be aligned with, amongst others, the Provincial SDF
(see below), the Eden SDF and Spatial Development Plans (SDPs).
The following aspects of the SDF have relevance to the EMP:
• The concept of sustainable development must inform all aspects of planning.
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• All people have the right to participate as equals in a collective development planning
process and in the decision-making processes, which determine the use of public
resources, and are furthermore entitled to fair and equal access to public facilities,
resources and opportunities.
• Extensive and effective technical consultation and public participation should be an
integral part of ongoing planning and management. Decision-making processes
should be consistent, clear and transparent.
• Settlements must sustain social equity, economic viability and ecological integrity.
This includes the edging of settlements (containing urban sprawl) to protect valuable
natural and agricultural resources.
• Natural resources are depleted and the natural environment is rapidly being degraded.
In addition, access to nature for recreation and escape is diminishing.
• Conservation Status (Figure 4.1):
- The Keurbooms Lagoon and Keurbooms and Bitou Estuaries are considered to be
critically endangered or endangered.
• Bio-regional Planning Framework4 (Figure 4.2)(informed by STEP; see Section
4.4.8):
- The area comprising the Keurbooms Nature Reserve is designated a Core
conservation area that should comprise a Type 1 Protected Area.
- The area between the two estuaries immediately above the N2 is designated a
Core conservation area comprising an area potentially available for protection
(Protected Area Type 3).
- The Keurbooms lagoon, the entire Bitou Estuary (including floodplain and
wetlands) and the remaining sections of the Keurbooms Estuary above the N2
bridge are designated as a variety of buffer zones designed to provide additional
protection to the Core Areas. The estuaries and lagoon buffer zone is inclusive of
a Core conservation area (protects ecological networks and processes).
• A Development Corridor is proposed, with land parcels on either side of the N2
between the Keurbooms Estuary and the Wittedrift Road to the west of
Kwanokuthula.
• The ecological networks and corridors identified in the Bio-regional Framework
should be used as the basis to establish an open space system for the Bitou area.
Similarly, Core and Coastal areas should be linked via ecological networks and
corridors to form a Municipal-wide open space system.
• The Keurbooms Estuary above the N2 bridge is excluded from the urban edge,
however, the lagoon, Keurbooms below the N2 bridge and entire Bitou Estuary are all
within the designated urban edge. The permissible levels of densification (dwelling
units/ha) are to be determined by the local Municipality as are areas where
densification would be deemed inappropriate.
• Under the Resource Conservation Policies, the following are applicable:
- The controls and actions governing land use are described for Core Areas and
Buffer Zones.
- Ribbon development along the coast should be prohibited, estuaries should not be
developed so as to maintain their ecological functioning and wetlands ecosystems
4 The descriptions (criteria) of various Bio-regional areas, their primary functions, and guidelines for
management and spatial planning are available in Part 5B of the SDF document.
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should be protected so as to maintain basic functioning (large parts of the
Keurbooms/Bitou systems fall within the designated urban edge).
- Agricultural lands and practices, including those within the urban edge, are
recognized and should be maintained provided they conform to legislation (e.g.
CARA).
- Existing wastewater treatment works must be improved and maintained to ensure
water quality of the water bodies with which they are associated.
- Water conservation and demand management for residential use must be
encouraged as this impacts on availability for farmers.
• The following Spatial Framework guidelines are applicable (italics are author’s
comments):
- Conservation areas should be protected from inappropriate development.
- Prevention of pollution of rivers and wetlands by contaminated stormwater.
- Control of inappropriate farming activities on land adjacent to rivers and
wetlands.
- Public access to wetlands must be managed to ensure sustainability and limit
degradation.
- In principle, no permanent structures for human habitation are permitted below
the 1:100 year floodline, which should form the setback for urban development.
In addition, development levels should be a minimum of 300 mm above flood
levels. These guidelines take into account climate change, which includes aspects
such as sea-level rise and the increase in frequency and intensity of flood and
storm events.
- Management strategies5 must allow for the conservation of sensitive areas.
- Rehabilitation of degraded natural systems should be undertaken where feasible.
- Allow for continuous flow of all culverts, river crossings and channels
- Infilling and dumping on floodplains and wetlands should be prevented.
- Rivers (presumably including estuaries) and associated terrestrial ecosystems
should be managed holistically.
- Sensitive areas, for the purpose of evaluating development proposals, include land
within 50 m of the high water mark, land under the 1:100 year floodline, declared
conservation areas, land of biological/scientific value, land with high to medium
agricultural value and areas containing aquifers or groundwater resources.
- Evaluation of development and rezoning applications within the urban edge must
take the following into account:
� Opportunities to enhance or retain environmental qualities.
� Assessment of physical aspects of the environment.
� Assessment of functioning of the biophysical and ecological environment and
protection of sensitive areas.
� Activities must ensure the least amount of environmental degradation.
� Impacts on the hydrological cycle in the catchment must be minimized.
� Impacts on sensitive environments must be limited to those that can be
mitigated and only if this is feasible and enforceable.
� Visual integrity of scenic assets must be reinforced.
5 This would include the Estuary Management Plan.
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Figure 4.1 Conservation status of the Bitou Municipal Area.
CONSERVATION STATUS
BITOUMAP 11
CONSERVATION STATUSCritically EndangeredEndangeredVulnerableCurrently Not VulnerableDECEMBER 2004
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Figure 4.2 Bio-regional Framework of the Bitou Municipal Area.
BIOSPHERE SPATIAL PLANNING CATEGORY C: TRANSITION AREAS (Spatial Planning Categories C: Agriculture, D: Urban-Related, E: Industry, F: Surface Infrastructure and Buildings)Transition Areas (Non-Destructive/Destructive Activities) (STEP Class: IV) (STEP Description: Currently not Vulnerable)
BIOSPHERE SPATIAL PLANNING CATEGORIES B AND C: BUFFER AND TRANSITION AREASBuffer Areas (Non-Destructive Activities) / Transition Areas (Non-Destructive/Destructive Activities) (STEP Class: III) (STEP Description: Vulnerable) (Impacted/Disturbed Areas)
BIOSPHERE SPATIAL PLANNING CATEGORY B: BUFFER AREASBuffer Areas (Restoration) (STEP Class: I) (STEP Description: Critically Endangered) (Impacted/Disturbed Areas)Buffer Areas (Restoration) (STEP Class: II) (STEP Description: Endangered) (Impacted/Disturbed Areas)
BIOSPHERE SPATIAL PLANNING CATEGORY B: BUFFER AREAS INCLUDING CORE AREASBuffer Areas including Core Areas (STEP Description: Ecological Networks and Processes)
BIOSPHERE SPATIAL PLANNING CATEGORY A: CORE AREASCore Areas (STEP Description: Protected Areas Type 1) (Owned and managed by the State, Province or a Local Authority - Conservation legislation is strong)Core Areas (STEP Description: Protected Areas Type 2) (Public or private land used for conservation and other land uses - Conservation legislation is weak or non-existent)
Core Areas (STEP Description: Protected Areas Type 3) (Areas potentially available for conservation)
MAP 1
BITOUBIOREGIONAL FRAMEWORK
DECEMBER 2004
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4.4.3 WESTERN CAPE PROVINCIAL SPATIAL DEVELOPMENT
FRAMEWORK (PSDF)
The purpose of the PSDF, an integrated provincial wide framework, is to;
• Be the spatial expression of the Provincial Growth and Development Strategy
(PGDS);
• guide (metropolitan, district and local) municipal integrated development plans
(IDPs) and spatial development frameworks (SDFs) and provincial and municipal
framework plans (i.e. sub-SDF spatial plans);
• help priorities and align investment and infrastructure plans of other provincial
departments, as well as national departments' and parastatals' plans and programmes
in the Province;
• provide clear signals to the private sector about desired development directions;
• increase predictability in the development environment, for example by establishing
no-go, conditional and ‘go’ areas for development; and,
• redress the spatial legacy of apartheid.
With regards taking climate change into account, the PSDF states that:
“No further urban development shall be permitted on open coast lines that are
vulnerable to erosion, inlets that are susceptible to increased storm activity, river
banks that are liable to flooding, coastal buffer zones and ecological setback lines in
estuaries and below the 1:50 year floodlines (erven) and the 1:100 year floodline
(building platform).”
This guideline has specific applications when it comes to developments within the
defined estuarine area, and in particular within the lower reaches of the Keurbooms
below the N2 which is heavily developed within both the 1:50 and 1:100 year floodlines,
and the Bitou above the N2, which is characterized by extensive floodplains.
4.4.4 GARDEN ROUTE INTIATIVE
The Garden Route Initiative (GRI) was established in 2004 with the aim of improving the
coordination of conservation actions between several organizations in order to achieve a
common goal. The objectives of the GRI are to identify priority biodiversity areas,
consolidate protected areas, promote conservation stewardship, incorporation biodiversity
priorities into land use planning and decision making and to ensure the sustainable
management effectiveness of the Garden Route conservation areas. In order to achieve
these objectives the GRI seeks to develop systems and structures that would enhance
communication, cooperation and coordination between stakeholders involved in
conservation activities within the area.
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4.4.5 A CLIMATE CHANGE STRATEGY AND ACTION PLAN FOR THE
WESTERN CAPE (DRAFT)
This Draft document (DEADP 2007) outlines a strategy (adaptation and mitigation) to
deal with the effects of climate change in the province. Vulnerable systems (areas)
include natural systems (water, biodiversity, and coastal and marine systems and
resources, economic sectors (agriculture, tourism and fisheries), economic resources and
infrastructure (energy, transport, health and air quality) and the built environment,
livelihoods and disasters (social systems and extreme events such as floods and fires). In
order to deal with these consequences, the strategy and action plan details the following
prioritized programmes or key outcomes (most of which are applicable to the estuary
management scenario):
• An integrated water supply and infrastructure management programme that integrates
climate impacts and risks. This involves researching the cost benefit of irrigation,
increasing water efficiency including through pricing strategies, establishing
uninterrupted water conservancy targets, systems maintenance and repairs and
establishing the ecological reserve.
• Establishing clear links between land stewardship, livelihoods and the economy. This
entails effective land use and land care; protection, maintenance and enhancement of
natural resources; strengthening vulnerable communities and protecting livelihoods
through targeted research; maintaining diversity in the economy; and integrating
climate risks into development planning.
• Establishing a focused climate change research and weather information programme.
• Reducing the Provincial carbon footprint. This can be achieved through energy
efficiency, development of renewable and alternate sustainable energy resources,
effective waste management strategies and cleaner fuel programmes for households
and transport.
4.4.6 COASTAL MANAGEMENT PROGRAMME
The development of Coastal Management Programmes (CMPs) is a requirement under
Chapter 6 of the ICMA. Sections 48 to 50 specifically make provision for municipal
CMPs, which would include estuaries. Essentially the EMP for the Keurbooms and Bitou
Estuaries would need to be integrated with the municipal CMP, which in turn may be
adopted as part of the IDP. Eden District has just initiated its CMP and it will be
developed over the next two years. Aspects of a CMP that are applicable to the estuary
environment include:
• Coastal Action Plans (CAP) need to be developed for pollution control & waste
management, natural resource management and awareness & education.
• A Coastal Working Group (or management committee) needs to be structured to
include all major stakeholder groups and senior managers, and their TOR need to be
formalized.
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• Land use and management guidelines must be developed in accordance with the
ICMA regulations.
• No development within dynamic coastal process areas (includes estuarine area) unless
for the purpose of protecting those areas.
• Inappropriately located infrastructure should be relocated and/or demolished.
• Management plans need to be developed for all conservation areas.
• Increase capacity of conservation staff (both numbers and education).
• A resource economics study is required to guide decision-making.
• Reserve determinations must be conducted for all estuaries.
• Abstraction rights from riverine systems need to be reviewed.
• Those responsible for environmental degradation must be held liable for rehabilitation
(polluter pays principle).
• Illegal waste disposal and littering needs to be minimized via pro-active and reactive
means.
4.4.7 CAPE ACTION FOR PEOPLE AND THE ENVIRONMENT
The C.A.P.E. is a project developed in partnership with the Global Environment Facility
(GEF) to secure the future of the Cape Floral Kingdom (also known as the Cape Floristic
Region). The C.A.P.E. project was made possible by a grant from the GEF and
established to develop a long-term strategy to conserve biodiversity in the terrestrial,
marine and freshwater ecosystems of the Cape Floral Kingdom (Table 4.4). The C.A.P.E.
project has a dedicated estuary management programme, which coordinates the
development of EMPs (including this one for the Keurbooms and Bitou Estuaries) within
the CFR.
Table 4.4 Themes and Strategic Components of C.A.P.E. (after DMP 2004).
THEMES STRATEGIC COMPONENTS
Conserving biodiversity in
priority areas
a) Strengthening on- and off-reserve conservation
b) Supporting bioregional planning
Using resources sustainably
a) Conserving biodiversity and natural resources in catchments
b) Improving the sustainability of harvesting
c) Promoting sustainable nature-based tourism
Strengthening institutions and
governance
a) Strengthening institutions
b) Enhancing co-operative governance
c) Promoting community involvement
C.A.P.E. has produced a Strategy and Action Plan, specific objectives of which include
the following (after DMP 2004):
• Establishing an effective reserve network, enhancing off-reserve conservation, and
supporting bioregional planning.
• Developing methods to ensure sustainable yields, promoting compliance with laws,
integrating biodiversity concerns into catchment management, and promoting nature-
based tourism.
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• Strengthening institutions, policies and laws, enhancing co-operative governance and
community participation, and supporting continued research.
4.4.8 SUBTROPICAL THICKET ECOSYSTEM PLAN
(Description taken from DMP 2004)
The Subtropical Thicket Ecosystem Plan (STEP) was a three-year project co-funded by
the GEF to identify priority areas for conservation actions in the thicket biome and to
ensure that national, provincial and local authorities implement the conservation plan.
The STEP project focuses on the core area of the Thicket Biome, which occurs between
the Groot-Gouritz river system in the west, the Kei River in the east, and the Great
Escarpment in the hinterland in the vicinity of Graaff-Reinet in the west to Queenstown
in the Eastern Cape.
The region includes the Albany Centre of plant endemism and overlaps in the west with
the Succulent Karoo Centre. Both are centres of diversity and endemism for succulents
and bulbs and are floristically the most important parts of the Thicket Biome. The
Albany Centre is a recognized WWF-IUCN global centre of plant biodiversity, and
nearly all of its plant endemics are components of the Thicket Biome. The Thicket
Biome in this region is thought to contain the most species-rich formations of woody
plants in South Africa. It overlaps with the Cape Floristic Region, which is the subject of
a major strategic conservation planning exercise.
The overall aim of STEP is to:
• Provide a detailed spatial analysis of the various thicket types.
• Assess the extent of their transformation and develop a better understanding of the
threats.
• Locate and design conservation areas to achieve explicit representation goals.
• Suggest and prioritize explicit conservation actions.
• Provide information for incorporation into regional Structure Plans and national
Environmental Management Frameworks.
• Provide a capacity building service in GIS-based conservation planning.
• Guide investors from the public and private sectors in the selection of land for
commercial enterprises, e.g. game-based ventures.
• Create an awareness of the value and plight of the Thicket Biome.
4.4.9 EDEN TO ADDO CORRIDOR INITIATIVE
The Eden to Addo Corridor Initiative aims to assist landowners to identify and develop a
living corridor from Eden to Addo by applying sound land-use practices, encouraging a
diversity of livelihoods and linking ecologically important areas, for the benefit of
wildlife and the extended community (Eden to Addo 2010). There are several initiatives
located in the upper and middle catchment regions of the Keurbooms and Bitou Rivers,
but the most pertinent initiative (in terms of the estuary) is that associated with the Bitou
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Wetland, which is seen as a vital corridor between the SANParks Forest Reserve and the
Keurbooms Nature Reserve. Initially, there appeared to be an overwhelming level of
support for this initiative, but recent developments (see Eden to Addo 2010; Section
3.3.1) have resulted in a rift between some landowners and Eden to Addo and the
initiative has been severely compromised. The future remains uncertain.
4.4.10 EXISTING MANAGEMENT PLANS (FRAMEWORKS)
There is currently no management plan for the Keurbooms/Bitou Estuaries. However,
management related issues are currently dealt with by relevant government departments;
primarily CapeNature, DWA, DAFF, DEADP and various municipal departments. There
is currently no environmental officer within the Bitou Municipality and the Eden District
official has to fulfill these obligations. This is less than ideal and needs to be rectified as a
matter of urgency. Local civil society organizations have had two management
frameworks drafted for different regions associated with the estuaries. These are
described below.
Keurboomstrand Preliminary Environmental Management Framework
The Keurbooms Property Owners Association privately funded this framework (Grant
Johnston Associates 2008) in order to identify critical or sensitive environments and raise
the general awareness about their importance and help guide future planning of
developments. Of particular relevance to the proposed EMP are the wetlands, specifically
saltmarshes and the Tshokwane River wetlands (located to the east of the Keurbooms
Estuary and seaward of the N2) that drain into the Keurbooms Estuary near the
Strandmeer Estate. Barriers to the natural drainage of this wetland into the Keurbooms
threaten to restrict freshwater flow into the system and further impacts could be
detrimental to overall ecosystem functioning. Other environments that may fall within the
defined estuary area, and therefore will need to be considered in the EMP are Knysna
afromontane forest, coastal forest and dune thicket, fynbos and coastal dune systems
(comprising foredunes, primary dunes, dune slack and secondary dunes). Reference is
also made to restricting development within certain zones, including the 1:50 year flood-
line (3.2 m above MSL), 100 m from the high water mark and below the 5 m contour.
The report also provides GIS maps of topography, ecosystems, ecological corridors and
sensitivity.
Lower Bitou/Keurbooms Catchment and Floodplain: Preliminary Environmental
Management Framework
The Plettenberg Bay Community Environment Forum privately funded this framework
(Grant Johnston Associates 2009) in order to identify critical or sensitive environments
with the aim of providing a framework within which appropriate development can be
assessed in the future. The report also provides GIS maps of topography, ecosystems,
ecological corridors and sensitivity. In terms of sensitivity, the report highlights both high
and moderate areas, many of which are applicable within the context of the proposed
EMP. These include wetlands and rivers, indigenous coastal forest and thicket, land
below the 5 m contour (all High) and areas with mixed alien trees (Moderate). Additional
ecosystems of note are fynbos and grassland (more catchment related), dune systems and
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coastal corridors on a larger scale. Three key environmental issues are identified, namely
climate change (includes sea-level rise and storm/flood events), water abstraction from
the Keurbooms River by the Bitou Municipality (includes reference to and
recommendations from the Rapid Ecological Reserve study by CSIR in 2008) and land
management within the catchment and floodplain (defined as area below 5 m contour).
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CHAPTER 5 – RECREATIONAL USE
5.1 EXPLOITATION OF LIVING RESOURCES
5.1.1 KING ET AL.
A fishery survey on the Keurbooms and Bitou Estuaries by King et al. (in prep.) from
September 2003 to August 2004 (roving creel surveys for 3 days each month, including 2
week days and a week-end day or public holiday) revealed the following:
• A total of 1 630 anglers were encountered during 32 sample days, of which 277 were
subject to detailed questionnaires and an additional 160 to catch inspections.
• The fishery is male dominated (92%)6 and comprised 68% whites, 38% coloured and
1% black.
• 48% of the participants are local (living within 30km of the estuaries).
• 68% were formally employed while only 9% were currently unemployed.
• Recreational shore-based anglers comprised 46% and boat-based anglers 52%7; only
2% were classified as subsistence8.
• 86% of anglers were not affiliated to any club.
• Subsistence anglers fish for substantially longer periods per outing (>9 hrs) than
shore- or boat-based anglers, who average approximately 3 hrs 30 min. 42% of
anglers undertake night-fishing outings as well.
• Effort is higher on weekends and public holidays for recreational anglers but no
difference was noted for subsistence users. Angler counts peak during the Christmas
and Easter holidays. An estimated 64 367 angler hours were fished during the survey
period.
• Effort was highest below the N2 road bridges for all sectors, with the confluence
region being a key focal point.
• Catch-per-unit-effort (cpue) was highest for boat-based anglers (0.07
fish/angler/hour) followed by subsistence anglers (0.03) and shore-based anglers
(0.02). Overall average cpue was 0.04 fish/angler/hour and total estimated harvest for
the survey period was 19 452 fish (6 573 kg).
• Only 32% of anglers catch at least one fish per outing and only 4% ever attain or
exceed the bag limit for a species (mostly R. holubi).
• Fourteen species were recorded in catches, of which Cape stumpnose was
numerically dominant (47%) followed by spotted grunter (25%) and white steenbras
(8%). Spotted grunter dominated the catch by weight (52%) followed by Cape
stumpnose (13%) and white steenbras (11%).
6 This may have changed as anecdotal information suggests that many more woman are now active.
7 Includes power driven vessels, canoes/fishing skis and rowing boats.
8 Note that although classed as subsistence in the survey, due to unemployment status or reliance on fish as
a food source, these anglers are not in possession of valid subsistence permits issued in terms of the MLRA.
According to Clark et al. (2002) there are between 50 and 60 subsistence fishers – this number is likely to
be somewhat larger by now.
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• The majority of fish caught were under the minimum legal size; 77% of Cape
stumpnose, 51% of spotted grunter and 100% of white steenbras. Sample size for
dusky kob (4) and leervis (5) were small but one and all were undersize respectively.
• 59% of anglers use bait collected exclusively from the estuaries; 13% use bait
collected and bought from retailers; 21% use bait exclusively bought from retailers;
4% used bait bought illegally from subsistence collectors9 and 3% used artificials.
10
• Most commonly used bait includes sandprawn (26%), pilchard (23%), mudprawn
(22%) and pencil bait (11%). The estimated harvest for sand and mudprawns over the
survey period was 199 891 and 185 742 respectively (no standing stock data is
available to estimate the proportion taken by collectors), with the majority of effort
being in the Poortjies area and adjacent to the caravan park in the mouth region.11
• Angler perceptions were that abundance and mean size of bait organisms has
declined, with 30% attributing this to over exploitation. Knowledge of bait
regulations was poor, with only 40% knowing the legal quota and 44% being in
possession of a permit.
• Knowledge of the fish regulations was also poor, with only 23% of anglers providing
correct minimum size limits for their target species. Minimum sizes also received the
lowest score in terms of effective regulations.
• Compliance monitoring effort appears to be low, with 72% of anglers never having
had their catches inspected. The frequency of inspection for 34% of those who have
been monitored is less than once in every 50 outings.
• 74% of anglers thought catches had decreased over time (catch rate and average size)
with A. japonicus, P. commersonnii and L. lithognathus being the most noteworthy.
• The high percentage of undersize fish kept by anglers was viewed as a major concern,
and an increase in compliance monitoring efforts combined with an awareness raising
campaign is strongly motivated.
5.1.2 ANECDOTAL INFORMATION
Anecdotal information gathered from stakeholders during site visits and meetings
between 11 and 13 February and 3 and 5 March revealed the following about the fishery:
• The fishery is diverse, comprising shore and boat-based anglers using a variety of
gear types (rod & reel and handlines).
• Up to 30 power driven boats may be active on the estuary per day during the year, but
during holiday season this may increase to between 300 and 400. The number of
boats registered by CapeNature for the past three years are 631, 566 and 583.
Although not all are involved with fishing activities, many will be.
9 Numbers of illegal bait sellers are not known, but they tend to ply their trade in the region of the N2
bridge over the Bitou, particularly during peak holiday periods (Henk Nieuwoudt, CapeNature, Pers.
Comm.). 10
Note that since the survey period it is likely that a greater percentage of anglers use artificials such as fly
and dropshot as this format has increased in popularity (and effectiveness) in recent years. As such, the
catch composition is likely to have changes as well, e.g. more dusky kob and leervis. 11
Observations during a site visit (11-13 February 2010) revealed a high collecting effort in the Bitou
estuary below the N2 bridge and around the Anath peninsula.
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• There are between 30 and 40 rowing boats used by fishermen mainly from New
Horizons with effort concentrated in the lagoon area.
• It is estimated that in excess of 150 and 100 anglers from New Horizons and
Wittedrift respectively fish in the two estuaries and lagoon; many of these are women.
Average time spent fishing by these members if 8 hours per outing, with those who
are employed fishing either at night during the week (shorter periods) or over
weekends. Effort is divided between the estuaries and the sea depending on where
fish are being caught. Sandprawn, mudprawn and pilchards (bought) are the dominant
bait items.
• Most effort (all user groups) is during daylight hours and below the N2 bridges, but a
large number of Wittedrift anglers fish between the N2 and old destroyed bridge on
the Bitou.
• Despite regular inspections by CapeNature officials, many anglers admit to keeping
undersize fish as this is a primary food source, particularly amongst the Wittedrift and
New Horizons communities.
• More dusky kob is being caught than previously due to use of artificials, particularly
in upper reaches above Whisky Creek (see footnote 6).
• Juvenile leervis present all year, with larger specimens in February/March.
• Elf present between November and April.
• Predominantly juvenile white steenbras are caught in the estuary.
• Skipjack present during warmer months and returning after a long absence.12
• There is a consensus that fishing has improved since the 2007 floods and that this was
good for the system.
• Illegal bait collecting methods (digging) is not prevalent, but illegal selling does take
place; prices are not fixed and fluctuate depending on demand. Some white anglers
pay New Horizons and Wittedrift community members to collect bait on their behalf
– mostly sandprawn, mudprawn and bloodworm.
• A charter operation takes clients fishing and promotes a catch-and-release ethic; all
forms of angling (bait, fly and artificials) are offered.
• Catches indicate that the systems are in good condition (health) at present.
• The availability and proposed price increase of recreational licenses was viewed as
problematic and in need of attention.
• Education and awareness programmes are required to inform users about regulations
and the importance of the estuaries in general.
• Conflict between user groups is not considered to be a major concern, although
speeding boats do pose a safety risk (to fishers in small rowing boats) and also snag
fishing lines.
• No-take sanctuary zones were recognized as important but site selection needs to be
based on sound scientific data.
• No fishing competitions take place on the estuary and stakeholders felt that this
should not change.
12
This is a trend observed in other permanently open estuaries such as Swartkops, Kariega and Bushmans.
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5.1.3 LICENSED SUBSISTENCE FISHERS
According to the Marine Living Resources Act (Act 18 of 1998; MLRA), Schedule 1,
Section 1 (lv), a subsistence fisher is defined as, “a natural person who regularly catches
fish for personal consumption or for the consumption of his or her dependants, including
one who engages from time to time in the local sale or barter of excess catch, but does not
include a person who engages on a substantial scale in the sale of fish on a commercial
basis.”
There are 65 subsistence exemptions (permits) that have been granted to fishers in The
Craggs for the year 2010 (expires 31 December 2010). These exemptions have been
issued in terms of Chapter 3, Part 2 (Section 19) of the MLRA, and allow for the catch
and sale of certain linefish species, both in the marine and estuary environment. There are
strict conditions linked to the permit, such as bag limits, size limits, species that may or
may not be sold and the use of boats. The permit does not allow for the sale of bait
organisms. The Keurbooms and Bitou are two of the closest estuaries to the The Craggs,
and as such may be utilized by these permit holders on occasion. For the most part,
however, these fishers fish in the marine environment. According to MCM records there
are no subsistence permits granted to any fishers residing in the communities (e.g.
Wittedrift and New Horizons) close to Plettenberg Bay.
5.2 TOURISM AND NON-CONSUMPTIVE USE
A host of non-consumptive activities take place primarily on the lagoon and Keurbooms
Estuary. The Bitou Estuary is not easily accessible by boat above the N2 bridge, and
although the floodplain and wetland complex has potential to be a premier bird watching
area, access through privately owned land is problematic. Landowners are willing to
allow members of the public access but need assurances that their property will be
respected – incidences of fires and littering have occurred in the past.
Plettenberg Bay and its surrounds are one of the major tourist destinations in South
Africa, attracting both local and overseas visitors. Despite this, the Keurbooms is not
specifically marketed as a destination but is usually included amongst other marketing
packages that incorporate the greater Plettenberg Bay area or the Garden Route. This was
recognized as a potential opportunity during a meeting with tourism stakeholders (March
3rd
) and the EMP will address the possibilities of marketing the area as a destination – a
joint venture between operators and Bitou Tourism).
Several resorts are available to the visitor, including the Keurbooms Lagoon Caravan
Park, Forever Resorts, the Keurbooms River Lodge (Protea Hotel) and the up market
Stanley’s Island. Numerous B&Bs and guesthouses also provide accommodation. Many
tourists own property close to the estuaries and are frequent visitors throughout the year.
There are also a large proportion of permanent residents who choose to live here.
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Activities that take place include:
• Appreciating nature – includes rest and relaxation, swimming, walking, canoeing,
power boating (slow cruises), bird watching and picnics (three sites in the upper
reaches of the Keurbooms administered by CapeNature). Guided tours with an
educational slant (wildlife, history) are offered on board two motorized barges.
• Water sports – predominantly water skiing above the N2 bridge on the Keurbooms
Estuary. Kite boarding, windsurfing and sailing may also take place (lagoon area).
• Sporting events – although the SA National Canoeing Championships have been held
on the Keurbooms there is considerable potential for it to host additional events such
as open water swimming, rowing and sailing (in the lagoon area).
Potential activities identified during stakeholder meetings include:
• Formal walking trails through the Keurbooms Nature Reserve in the middle to upper
reaches of the Keurbooms Estuary.
• Educational workshops for school groups (possible venue is Anath Peninsula) to
create an awareness of the importance of estuaries.
• Snorkeling trails linked to the Knysna seahorse.
• Additional sporting events (see above).
• Package holidays that include a variety of activities associated directly with the
estuaries or indirectly, e.g. golf at Goose Valley.
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CHAPTER 6 – WATER QUANTITY AND QUALITY
6.1 INTRODUCTION
This section of the Report focuses on the contribution of freshwater systems to the
maintenance of the Keurbooms and Bitou Estuaries. Current pressures on freshwater
systems include increased abstraction volumes to supply agricultural and domestic needs
within the Bitou Municipality, driven by an increase in development both in the formal
and informal housing sectors, together with the required infrastructure. A number of golf
and polo (equestrian estates) are also found within the management area.
6.2 MANAGEMENT OF THE CATCHMENT
The Keurbooms/Bitou catchment’s management structures consist of a number of
national, local and municipal structures. These can be listed as follows:
• Department of Environmental Affairs, inclusive of the Directorate Marine and Coastal
Management on a national level.
• Western Cape Department of Environmental Affairs and Development Planning at the
provincial level.
- Responsible for the management of the estuarine area, including ensuring
compliance in terms of the MLRA (e.g. subsistence and recreational fishing).
• Department of Water Affairs (previously known as the Department of Water Affairs
and Forestry) at the national and provincial level.
- Responsible for all water-related issues, i.e. catchment management, Resource
Directed Measures (RDM) for protection of freshwater resources (i.e. determining
Ecological Water Requirements (EWR) and setting the Reserve), planning,
infrastructure, monitoring river health, enforcing discharge standards and dam
safety etc.
• Other national and provincial offices of departments/directorates, e.g. Agriculture,
Forestry, Tourism and Land Affairs.
• Bitou Municipality within the Eden District Municipality.
- As the delegated authority the municipality is currently responsible for the overall
management of the Bitou/Keurbooms systems.
6.3 CATCHMENT DESCRIPTION
The Keurbooms and Bitou river catchments are located in the Gourits Water
Management Area (WMA) 16. The catchments of these two rivers have been measured at
1 085 km2 (Day 1981), 1 188 km
2 (Heydorn and Tinley 1980) and 1 270 km
2 (Haigh and
Bekker 2005) respectively, with the Keurbooms being estimated at 70 km in length
(James and Harrison 2008) and the Bitou River at 23 km from its confluence with the
Keurbooms to its head (Bornman and Adams 2005). The river systems extend from the
Witberg and Tsitsikamma mountains in the North to the coast in the South, with the
Keurbooms having few floodplain areas as it is located within incised river gorges for
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most of it length. The Palmiet River is the principal tributary of the Keurbooms and
originates in the K60D quaternary catchment.
The rivers drain the K60 catchment (Figure 6.1), which includes quaternary catchments
K60A, B C, D, E and F. A small tributary which falls within K60G also forms part of the
Bitou catchment, and flows directly through the Plettenberg Bay Sewage Treatment
Works (STW) at Gansevalei. After passing the reclamation ponds of the STW, the Ganse
Spruit flows through wetlands and water features of the Goose Valley golf course and
then onto the large Ganse Spruit wetland (also known as Ganse Vlei or Gansespruit Vlei),
with any resultant flows entering the Bitou Estuary. It should be noted that the Piesang
River also forms part of K60G, but forms part of an independent catchment and estuary
and not part of this study.
Figure 6.1 Locality map indicating the various quaternary catchments associated with the
Keurbooms / Bitou rivers (from Haigh and Bekker 2005).
Table 6.1 summarizes the main tributaries found associated with the Keurbooms/Bitou
quaternary catchments and the Mean Annual Precipitation (MaP) values (Haigh and
Bekker 2005), with the exception of K60G as discussed above.
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Table 6.1 Details of the quaternary catchments of the Keurbooms catchment K60.
Quaternary
catchment
Size Ha (km2) MaP (mm) Rivers/ streams
K60A 16 145 (162) 664 Kykoe, Kleinbosloop, Bos, Jaggakamma, Pieters, Keurbooms River exits
K60B 14n317 (143) 754 Voogds, Kwaai, Witels, Keurbooms River exits
K60C 16 081 (161) 744 Jakkalskraal, Uitvlugt, Diep, Klein, Keurbooms River exits
K60D 29 247 (292) 815 Kleinpalmiet, Langbos, Keur, Soetkraal, Dwarsrivier, Tarkakloof, Palmiet River exits
K60F 24 207 (242) 806 Rondbos, Kransbos, Petrus Brand, Ouhoogte, Leermansdrif, Bosfontein, Diep, Bitou
River exits into Keurbooms Estuary
K60E 10 017 (100) 775 Duiwelsgat, Whiskey Creek, Keurbooms Estuary
Source: WR90
Plettenberg Bay receives rainfall all-year-round with peaks in autumn (March/April) and
spring (August to November; Figure 6.2). The higher rainfall for Plettenberg Bay in
spring (dominant rainfall period) is a product of the late winter frontal systems together
with the effect of orographic rain resulting from the proximity to the coastal mountains.
The rain is mainly cyclonic and orographic, while thunderstorms are rare. Winter rainfall
is associated with the increase in cold fronts (east moving cyclones) passing over the
coast (Bornman and Adams 2005).
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Month
25
30
35
40
45
50
55
60
65
70
75
80
85
Me
an
ra
infa
ll (
mm
)
Mean annual precipitation 1984 - 2003 = 671 mm
Figure 6.2 Mean monthly precipitation over 20 years from 1984 to May 2004.
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The only major dam in the catchment is the Roodefontein Dam, which was raised to
2x106 m
3 capacity in 2003. Environmental releases of 0.31x10
6m
3 are made from this
dam to meet requirements at IFR5 downstream of the confluence of the Keurbooms and
Palmiet rivers. Values were taken from the 1996 Keurbooms IFR study. Farm dams are
mostly situated in the Upper and Lower Keurbooms River and Piesang River. The Bitou
Municipality’s water sources are shown in Table 6.2 (Anonymous 2006).
Table 6.2 Present and future water sources of the Bitou Municipality.
Town Current source of supply Future source of supply
Plettenberg Bay Pumping from the Keurbooms River, just below the
confluence with the Palmiet; Roodefontein Dam (also
irrigation abstraction for Jakkalsdraai); and six inland
boreholes (although saline intrusion limits use).
Off-channel storage adjacent to Keurbooms River.
Raise Roodefontein Dam + increase pumping from
Keurbooms during high demand periods.
Keurboomstrand Keurbooms aquifer via wells and boreholes. Off-channel storage in Matjies River. Share of Bufels
River Dam. Obtain water directly from Plettenberg Bay
works.
Kurland Small pool in Wit River, run-of-river abstraction. Unknown
Nature’s Valley Natural pool in Groot River; run-of-river pumping
scheme.
Unknown
Land-use in the upper catchment is predominantly natural forest, mountain fynbos and
grasslands, while the middle and lower catchments are used more extensively for
agriculture, residential and recreational purposes. No significant increases in irrigation,
forestry or farm dams are expected up to 2025 (Anonymous 2006).
The topography of the Keurbooms/Bitou area is dominated by the low-lying estuary and
its floodplain, while the inland reaches and upper catchments are dominated by
mountainous valleys and ridges. Figure 6.3 represents the middle and lower reaches of
the Keurbooms and Bitou Estuaries, inclusive of the Keurbooms Lagoon.
6.4 ECOLOGICAL STATUS
6.4.1 RIVERS
Biological monitoring activities of the Keurbooms and Bitou rives were undertaken as
part of a provincial initiative between DWA and CapeNature in order to fulfill the
objectives of the national River Health Programme (RHP). The RHP has the overall goal
of delivering ecological information about rivers (and link up with other aquatic
ecosystems, wetlands and estuaries monitoring initiatives), required to support the
national management of these systems. The RHP is designed to develop the capacity and
information base required to enable DWA and other role players to report on the
ecological state of South Africa’s river systems, in an objective and scientifically sound
manner. The information products generated by the RHP assist in distinguishing between
aquatic ecosystems exposed to sustainable utilization and those experiencing ecological
deterioration. It also allows for subsequent audits of management strategies and actions
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implemented to improve or maintain the ecological status of aquatic ecosystems. The
RHP determines the ecological state of river ecosystems in South Africa by evaluating
physical drivers such as geomorphology, water quality and habitat integrity, as well as
biotic indicators such as fish, macroinvertebrates and riparian vegetation. Two national
RHP sites are found on the Keurbooms River.
Figure 6.3 The middle and lower reaches of the Keurbooms Estuary (after Bornman and
Adams 2005).
A field survey of one of the national RHP Keurbooms sites, and a site on the Bitou River,
was undertaken by the CapeNature River Conservation Unit in the Gouritz WMA during
23 – 27 November 2009. The second national RHP site was inaccessible and could not be
monitored. Intensive monitoring of sites in the Gouritz WMA will commence in the
2011/2012 financial year. Results of the November survey are shown below. Indices used
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for the assessment were the geomorphological index (SASS5) for macroinvertebrates and
the Index of Habitat Integrity (IHI; DWA 2009).
Keurbooms River RHP site: K6KEUR-RHINO
The site is situated at the Rhino base camp at the DWA weir (33056’19.3’’ S;
23021’58.3’’ E), but could not be accessed due to very steep banks. A site was selected
approximately 100m upstream of the original site at a low water bridge.
• Macroinvertebrates (SASS5): This site is characterized by a high species diversity,
with a high sensitivity score. The results show that this site is in a Natural condition.
• Geomorphology: The Geomorphological Index (GI) shows that this site is in a C
category in terms of its geomorphological state. Clearing the recruits of black wattle is
needed and would require effective management.
• IHI: A number of abstraction pipes were seen at the site, with serious modifications to
the non-active channel, e.g. road construction, bridges, bulldozing and debris, and
infestation by alien trees. A large portion of the left-hand bank has been modified. A
moderate infestation of alien vegetation was seen in the riparian zone.
Bitou River site: K6BITO-WITTE
The site is at the head of the estuary at the road bridge and causeway at the Wittedrift
turning (33º59’58.4” S; 23º20’27.5” E).
• Macroinvertebrates (SASS5): SASS5 was not undertaken as suitable biotopes were
not available for sampling.
• Geomorphology: No results shown in DWA (2009).
• IHI: Modification of flow evident by two water abstraction devices and two bridges
(road bridge and old low bridge/causeway). The riparian zone appeared highly
susceptible to erosion.
6.4.2 CONCLUSION
The Keurbooms catchment has received little attention in terms of long-term monitoring,
with the focus being almost entirely on the estuary.
6.5 WETLANDS
A large number of freshwater wetlands are found within both the river catchments, with
58 wetlands surveyed by Haigh and Bekker (2005). Storage in farm dams and direct
abstraction for fruit farming, pasture cultivation, forestry and alien plant infestations,
have resulted in the degradation of several wetlands. These impacts have also resulted in
the disturbance of the riparian zones within the catchments.
Quaternary catchment K60D was rated as having the highest number of wetlands and
river-associated riparian systems that remain in a good condition, while K60E was the
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poorest with a large plantation block (Keurbooms State Forest) being cultivated directly
within the wetlands, and resulting in eroded areas. As catchment K60D is the principal
water source for the Keurbooms and Bitou Estuaries, the maintenance of its wetlands are
of paramount importance. The largest wetlands are found within K60F, i.e. the Bitou
catchment (Haigh and Bekker 2005).
6.6 WATER QUANTITY
Thirteen gauging stations or plates have been used to record flow data for various periods
starting in 1961. These are mostly located along the upper and lower reaches of the
Keurbooms River. Table 6.3 indicates the monthly volumes recorded at the Newlands
gauging weir (K6H019A01 - 33° 56’ 45" S 23°22' 03" E) on the Keurbooms River for the
period 1997 to present. Peaks in run-off volumes are evident throughout the year.
Although the estuary is flood tide dominated, with the scour by tidal flows removing
wave deposited sand to maintain the inlet channel and allow tidal exchange, river floods
also have an important function. These floods temporarily scour open inlets and remove
tidal-accumulated sediment from the lower reaches of the estuary (Reddering 1981;
1999).
Past studies (Duvenhage and Morant 1984) have noted that the Mean Annual Runoff
(MAR) of the Keurbooms River was highly variable and mirrors rainfall in the region.
However, all studies agree that the lowest runoff is recorded at times when the water
demand is highest.
Table 6.3 Monthly flow volumes (x 106 m
3) for Newlands K6H019A01 gauging station
for 1997 to present (# indicates incomplete data set).
Year Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Total
97/98 # 2.49 2.43 4.82 1.48 9.4 4.48 5.77 2.11 3.67 12.3 5.66 #
98/99 7.15 7.49 15.7 9.16 8.94 7.64 6.76 2.56 1.7 3.24 2.82 4.29 77.4
99/00 11.6 2.07 1.88 8.02 5.78 20.9 8.42 2.31 1.77 1.43 1.16 2.02 67.3
00/01 3.69 12.7 1.95 19.6 4.44 4.86 9.23 2.15 1.49 2.74 3.88 4.39 71.1
01/02 6.7 6.04 5.87 2.82 2.55 1.38 1.07 1.69 2.3 10.3 9.24 35 85
02/03 2.71 5.74 5.65 2.98 3.75 29 6.75 14.3 11.2 4.57 3.25 3.95 93.9
03/04 4.24 3.48 2.83 3.39 5.64 8.62 2.5 2.09 2.51 1.9 3.77 12.6 53.5
04/05 12.2 1.56 18 14 4.46 6.1 12.2 2.43 2.26 1.54 0.99 1.14 76.9
05/06 1.13 6.33 2.72 7.29 1.9 6.21 6.47 21.8 5.52 3.88 63.4 9.69 136
06/07 7.9 5.14 9.58 4 2.95 15.9 2.67 10.4 2.71 4.27 4.23 2.6 72.4
07/08 10.2 15.7 39 22.3 10.6 6.87 3.54 2.56 2.71 2.43 3.27 2 121
08'09 17.2 10.3 1.1 0.42 0 0.42 1.72 1.26 2.91 4.51 1.65 2.02 43.5
09/10 3.54 1.18 2.18 1.39 # # # # # # # # #
Max. 17.2 15.7 39 22.3 10.6 29 12.2 21.8 11.2 10.3 63.4 35 136
Min. 1.13 1.18 1.1 0.42 0 0.42 1.07 1.26 1.49 1.43 0.99 1.14 43.5
Ave. 7.36 6.17 8.38 7.71 4.37 9.78 5.48 5.78 3.27 3.71 9.16 7.11 81.64
Month
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Table 6.4 summarizes the various measured and/or predicted MAR values estimated by
various authors. See Section 6.8.3 for the final flow figures used during the Rapid
Reserve study of 2007.
Table 6.4 MAR values for the Keurbooms and Bitou rivers (after Bornman and Adams
2005).
Reference Keurbooms
X 106m
3
Bitou
x
106m
3
Total
x 106m
3
Midgley and Pitman (1969) 127 32 159
Noble and Hemens (1978) 160
Reddering (1981) > 72.9
DWAF 1978 (In Duvenhage and Morant, 1984) 64
DWAF 1981 (In Duvenhage and Morant, 1984) 71
Ninham Shand (1999; 2003) 154 33 187 (at mouth)
Instream Flow Requirements (IFR), i.e. the flow portion of the Ecological Reserve (or
Ecological Water Requirements), for the Keurbooms Estuary were estimated at
approximately 144 x 106 m
3 per annum or 77% of the present day MAR estimated in
1999 at the estuary (Luger 1999). A conservative approach was followed due to the
paucity of information, with results indicating that the estuary required 100% of present
day flows (or baseflows reaching the estuary). These figures were updated during the
Rapid Reserve study of 2007 (Bitou Municipality 2008) - see Section 6.8.3.
6.7 WATER QUALITY
Figures below indicate nutrient levels for the Keurbooms River and Estuary respectively
(Duvenhage and Morant 1984). The Keurbooms Estuary is considered oligotrophic,
meaning that increases in nutrients (i.e. organic materials) could have negative effects on
the biogeochemistry of the system.
River
Nitrate and Nitrite: 0 – 0.48 mg/L
Ammonia: 0 – 0.71 mg/L
Inorganic orthophosphate: 0 – 0.16 mg/L
Estuary
Nitrate: 3.5 – 4.5 mg/L
Inorganic orthophosphate: 0 – 0.9 mg/L
High nutrient levels in the estuary have been attributed to the release of sewage into the
Bitou Estuary via the Gans Spruit into the Gansvlei (Duvenhage and Morant 1984),
which increases the flux of nutrient into the system. Snow (2005; unpublished data cited
in Bornman and Adams 2005) observed the following nutrient levels in the Keurbooms
Estuary during a minor flood in 2002: Total Organic Nitrogen ranged from 23.17 µM in
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the upper reaches to 3.58 µM in the lower reaches; PO4 ranged from 1.96 µM in the
upper reaches to 2.55 at the confluence with the Bitou; No detectable concentrations of
NH4 was found in the estuary; Silicate ranged from 35.02 in the upper reaches to 81.3 at
the confluence of the Bitou.
Note that as the town and hence the demand for water grows, so will the volume of
sewage that needs to be discharged. However, most of the treated sewage is currently
used to irrigate existing golf courses and polo fields (Bornman and Adams 2005).
Copper, zinc, iron, manganese, cobalt, nickel and mercury in the surface water showed
average values for Eastern Cape rivers (Watling and Watling, 1980), with the
concentrations of metals in the sediment and water column in the Keurbooms River and
estuary being lower than those observed for the Bitou River. This was attributed the
natural mineralization processes known to occur in the Bitou River catchment.
No industrial activities take place in the catchment of the Keurbooms or Bitou Rivers.
6.8 ECOLOGICAL WATER REQUIREMENTS
6.8.1 BACKGROUND
The information below is modified from a stakeholder newsletter produced for the
Kromme/Seekoei Intermediate Reserve study of 2003-2006 (DWAF 2004), and is
included for clarification purposes (description of terms is provided in the text box).
The NWA (Chapter 3, Part 3) provides for the protection of significant water resources
through the Reserve. As the DWA is the custodian of the nation’s water resources, it is
the Department’s responsibility to ensure the adequate protection, effective management
and sustainable utilisation of these resources. The Resources Directed Measures (RDM)
Directorate is the Chief Directorate within DWA tasked with the responsibility of
ensuring that Reserve requirements, which have priority over other uses in terms of the
Act, are determined before licensing applications can be processed, particularly in
water-stressed catchments. Reserve determinations can be conducted at a Desktop, Rapid,
Intermediate or Comprehensive level. Each level of determination entails a more detailed
(higher confidence) investigation than the previous level. These determinations have to
take place before the water allocation process (compulsory licensing) can proceed.
Once Reserve requirements are available, the allocable resource could be determined and
water use applications evaluated.
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This means that human (Basic Human Needs Reserve) and ecological requirements
(Ecological Water Requirements, EWR, or the Ecological Reserve) need to be met before
flow can be harnessed for other users. These requirements are set and have to be
maintained at points along the rivers, streams and estuary. Points are selected via a
rigorous process as they must be representative of stretches of river, and are called EWR
sites. Flow, quality and biotic health objectives are set for these points. Future monitoring
is then conducted against these objectives to ensure that Reserve requirements are being
met.
One of the first steps of the Ecological Reserve process is EcoClassification, or
Ecological Classification. This step refers to the determination and categorization of the
Present Ecological State (PES) of various biophysical attributes (i.e. drivers such as
hydrology, water quality and geomorphology; biotic responses such as fish and
macroinvertebrates; and riparian vegetation) relative to the natural unimpacted reference
condition (Kleynhans and Louw 2007). Once the PES of these variables has been
determined, the EcoStatus, or integrated ecological state is assigned according to the
classification shown in Table 6.5. A description of each A-F category is shown in Table
6.6. The Recommended Ecological Category (REC) is the output of the EWR process.
Reserve: The quantity and quality of water needed to sustain basic
human needs and ecosystems (e.g. estuaries, rivers, lakes,
groundwater and wetlands) to ensure ecologically sustainable
development and utilisation of a water resource. The
Ecological Reserve pertains specifically to aquatic ecosystems.
Reserve requirements: The quality, quantity and reliability of water
needed to satisfy the requirements of basic human needs and
the Ecological Reserve.
Ecological Reserve determination study: The study undertaken to
determine Ecological Reserve requirements.
Licensing applications: Water users are required (by legislation) to
apply for licenses prior to extracting water resources from a
water catchment.
Catchment: The area in which all water ultimately flows into the
same river.
Ecological Water Requirements: This is the quality and quantity of
water flowing through a natural stream course that is needed to
sustain in-stream functions and ecosystem integrity at an
acceptable level as determined during a EWR study.
Water allocation process (compulsory licensing): This is a
process where all existing and new water users are requested to
reapply for their licenses, particularly in stressed catchments
where there is an over-allocation of water or an inequitable
distribution of entitlements.
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Table 6.5 Generic ecological categories for EcoStatus components (DWAF 2008;
modified from Kleynhans et al. 2005).
Table 6.6 Generic ecological categories for EcoStatus components (Kleynhans et al.
2005).
ECOLOGICAL
CATEGORY DESCRIPTION
A
Unmodified, natural.
B
Largely natural with few modifications. A small change in
natural habitats and biota may have taken place but the
ecosystem functions are essentially unchanged.
C
Moderately modified. Loss and change of natural habitat and
biota have occurred, but the basic ecosystem functions are still
predominantly unchanged.
D
Largely modified. A large loss of natural habitat, biota and basic
ecosystem functions has occurred.
E
Seriously modified. The loss of natural habitat, biota and basic
ecosystem functions is extensive.
F
Critically / Extremely modified. Modifications have reached a
critical level and the system has been modified completely with
an almost complete loss of natural habitat and biota. In the worst
instances the basic ecosystem functions have been destroyed and
the changes are irreversible.
DEVI ATION FROM
REFERENCE CONDITIONSA- F CATEGORIES SCORE
A ? 92.01
A/B >87 .4 and <92.01
B 8 2.01 – 87 .4
B/C >77 .4 and <82.01
C 6 2.01 – 77 .4
C/D >57 .4 and <62.01
D 4 2.01 – 57 .4
D/E >37 .4 and <42.01
E 2 2.01 – 37 .4
E/F >17 .4 and <22.01Serious change
No cha nge
Small change
Moderate change
Large change
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6.8.2 KEURBOOMS RIVER RESERVE ASSESSMENTS
The RDM surface water database of January 2009, and the Reserve tracking system of
August 2009, was used to identify where Reserve data are available for the Keurbooms
system, i.e. WMA16.
Note the following conditions concerning the use of these databases.
• The database is continuously updated, and only accounts for the Reserves that have
been determined up to the dates indicated, but an attempt has been made to access the
most recent information.
• The database, and associated Reserve templates, is prepared in response to Water Use
License Applications (WULA). Reserve templates are therefore relevant only to the
water use for which the Reserve was requested. New applications would therefore
require an assessment of currently determined Reserves, or re-calculation of the
Reserve.
• The database is specifically concerned with surface waters.
Information on the Keurbooms/Bitou quaternary catchments where Reserve
determinations have been conducted at any level of confidence, are shown in Appendix
II, and include assessments for K60C, D, E (all the Keurbooms River) and F (Bitou
River).
6.8.3 KEURBOOMS ESTUARY RESERVE ASSESSMENT
A Rapid (desktop) Reserve determination was conducted for the Keurbooms Estuary
(K60E/F/G), consisting of the Keurbooms and Bitou river arms, in 2007 (Bitou
Municipality 2008). The Reserve was commissioned by the Bitou Municipality out of
concern for the integrity of the Keurbooms and Bitou Estuaries as various Water Use
Licence Applications (WULAs) have been approved in the K60 tertiary catchment, which
concern some of the rivers that feed into the estuaries (Reserve Draft Template, April
2010).
The geographical boundaries of the estuary were defined as follows for the purposes of
the Reserve study (Figure 6.4):
• Downstream boundary: Estuary mouth (34° 2'31.99"S, 23°23'2.53"E) (This is a
relative position as the Keurbooms The shallow estuary mouth is highly mobile and
regularly changes position along the sand berm at the mouth);
• Upstream boundary – Keurbooms arm: Approximately 12.5 km upstream of the
mouth (33°57'8.04"S, 23°24'6.51"E);
• Upstream boundary – Bitou arm: Approximately 12.8 km upstream of the mouth
(33°59'58.44"S, 23°20'27.49"E); and
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• Lateral boundaries: 5 m contour above mean sea level along the banks, a delineation
that could be readily referenced from an ortho-photograph of the area.
Map source: Google Earth, 2006
Figure 6.4 Extent of the Keurbooms and Bitou Estuaries as used for the Reserve
determination study – 5 m contour line not shown (Bitou Municipality 2008).
Note that the Rapid Reserve study relied on existing data and no new data were collected.
The accuracy of the study depends largely on the accuracy of the simulated runoff data
and measured flow data. River flow data from the Keurbooms River were available from
November 1997. The overall confidence in the hydrological data provided to the
estuarine team by Ninham Shand Consulting Services was considered to be Medium
(Bitou Municipality 2008).
The Estuarine Health Index (EHI) score for the estuary indicated that the estuary’s
(Keurbooms/Bitou) Present Ecological State is in an A/B Category. In terms of the
importance the estuary was signified as a highly important estuary and is listed as a
Desired Protected Area in the C.A.P.E. Estuaries Conservation Plan for the temperate
areas of South Africa (Turpie and Clark 2007), and thus should be managed for Category
A or Best Attainable State (BAS). However, the system cannot be rehabilitated to a
Category A due to the pressures contributing to the present state of the estuary. Thus,
Category A/B was considered the BAS or the Recommended Ecological Category (REC).
An A/B category represents a largely natural state (see Tables 6.5 and 6.6).
The quantification of Ecological Reserve Scenarios was undertaken as part of the Reserve
assessment – results are shown in Table 6.7 (Bitou Municipality 2008; Reserve Template
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2010). The evaluation of the simulated runoff scenarios was used to derive the REC. The
REC was defined as the runoff scenario (or a slight modification thereof) that represents
the highest reduction in river inflow that will still protect the aquatic ecosystem of the
estuary and keep it in the required category. In evaluating Future Scenarios 1 to 4 it was
assumed that only river inflow from the Keurbooms catchment will be reduced and that
all other related anthropogenic activities (e.g. fishing, bait collection, power boating and
human disturbance) will remain at present levels. Taking the above into account,
Scenario 1 was selected as the REC for the Keurbooms Estuary as this scenario will
maintain the estuary in an A/B category with less impact on the environment (with only 8
% of the MAR reduced from reference state), while allowing some use of the estuary.
Table 6.7 A summary of the mean annual runoffs (MAR) of the various Simulated
Monthly Runoff Scenarios used for this Rapid level determination with the PES under
each scenario.
The estuarine specialists who were a part of the Reserve study team also concluded that
Future Scenario 2 probably does not pose a serious risk to the health of the
Keurbooms/Bitou Estuaries, but that more data will be required over the next few years to
increase the overall confidence in the study. This includes additional data on mouth and
sediment dynamics, water quality and invertebrates. Such data will improve the estuarine
specialists’ overall understanding of the system’s response to flow reduction.
6.8.4 PRELIMINARY RESERVE TEMPLATE (APRIL 2010)
The draft Preliminary Reserve template (see below) was obtained from Chief Directorate:
Resource Directed Measures (CD: RDM) at DWA in April 2010, and conditions and
background are shown below. Note that upon completion, these values will be signed by
the Chief Director of the CD: RDM, and Gazetted for implementation to manage the
Na me De scription
Keurbooms
MAR
(MCM/a)
Bitou
MAR
(MCM/a)
Combine d
MAR
(MCM /a)
% natural
M AR PES
Re ference Reference Con dition 174 58 232 100% A
PresentPresent State, including a diversion of 0. 1 m
3/s
to Pletten berg Bay164 51 215 92.70% A/B
Future
Scenario 1
As at Present State but the diversion is
increased to 0.45 m3
/s , no off-channel
s tora ge, 0. 145 m3
/s to Roode fontein,
include Rive r EWR
1 63 5 1 214 92. 20% A/ B
Future
Scenario 2
As at Present Stat e but the diversion is
increase d to 0.45 m3/s with off-ch annel
storage, 0.29 m3/s to Roo defontein, inclu de
River EW R
157 51 208 89.70% A/B
Future
Scenario 3
As at Present Stat e but the diversion is
increased to 0.65 m 3/ s a bst raction
(unconstrained), include River EWR
148 51 199 85.80% B
Future
Scenario 4
As at Present Stat e but the diversion is
increased to 1 .0 m3/s (u ncon strained), include
River EW R
140 51 191 82.30% B
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Keurbooms and Bitou Estuaries. Note that due to the low confidence of the extrapolated
results of this preliminary determination of the Reserve, the results should not be used to
evaluate high impact water use activities.
*Keurbooms Estuary includes both the Keurbooms and Bitou systems.
The objectives of the CD: RDM are to at least maintain, and if possible to improve
the PES of the estuary. The following conditions have been incorporated into the
letter to the region from CD: RDM, based on the result of the Keurbooms Estuary
Reserve study. Text is taken directly from the letter to the region (received from Jafta,
CD: RDM, April 2010).
To meet the EWR, there had to be some assumptions and limitations on the hydrology.
There was an agreed interim requirement that the diversions be reduced or stopped when
the river flow decreases below 0.3 m3/s and the diversion capacities were reduced by a
22/24 hour factor to account for breakdowns or power supply. It was also proposed that
the river inflow to the Bitou Arm of the Keurbooms system should remain similar to the
present state because: the Bitou Arm comprises an important, ecologically sensitive
wetland; the baseflows from the Bitou River are very low and it would be very easy to
remove all flows to the Bitou Arm of the estuary; the upper part of the Bitou Arm is very
narrow and shallow and potentially very sensitive to changes in flows; and due to the
absence of data (i.e. only one hydrographical station located in the lower part of the Bitou
Arm) no recommendations could be made regarding future abstraction from the Bitou
catchment.
6.8.5 NON-FLOW RELATED CONSIDERATIONS
The present ecological functioning of the Keurbooms Estuary is influenced by a number
of anthropogenic non-flow related issues. The correct management of these issues has the
potential, in conjunction with managing flows, to improve the ecological functioning of
the system and therefore the goods and services they provide. The following
recommendations should be considered.
Since the Keurbooms Estuary is a highly important system from both a socio-economic
and ecological perspective it is recommended that a project be initiated whereby the loss
in water column habitat (that would be incurred under Scenario 1) be mitigated for by
restoring some of the intertidal habitat and wetland vegetation to more natural conditions
where possible, as proposed in the Keurbooms/Bitou Estuarine Wetland Assessment
(Bornman and Adams 2006).
If the scenario recommended by the rapid reserve determination study were to be
implemented, it was recommended that the following mitigation measures be investigated
Water
re sourceW MA
Quaternary
catchmentPES EIS R EC
vMAR
(MCM)
Reserve (% of
vM AR)
Level of Reserve
Dete rmination
Keurbooms
Estua ryGo uritz K60E/F A/B High A/B 232 92.2 Rapid
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(with full stakeholder participation) and incorporated in the license agreement between
the Bitou Municipality and DWA (Bornman and Adams 2006):
12. Bitou Drift: The drift through the Bitou River should be removed in total including all
foreign rock material.
13. Northern floodplain of the lower Bitou Estuary: Remove all exotic invasive trees from
the flood plain. No further development should be allowed on the floodplain to
prevent further loss of floodplain functionality. Remove the old gravel road to the
south of the R340.
14. Southern floodplain of the lower Bitou Estuary: Remove all exotic invasive plant
species from the floodplain, remove the infilling, create a buffer zone (~ 10 m wide
separating the wetland from the agricultural activities on the floodplain).
15. Road Bridge across the lower Bitou Estuary: Remove concrete piers of the old road
bridge to facilitate flow and tidal exchange in the Bitou Estuary and establish
connection with old Bitou channel.
16. Middle reaches of the Keurbooms Estuary: Remove all alien trees from the banks and
The Island. Establish a buffer adjacent to the estuary and restrict new development on
the banks of the estuary.
17. Upper reaches of the Ganse Spruit: Remove all exotic vegetation from the stream
bed.
18. The Ganse Spruit Wetlands: Install a sufficient number of large culverts in the
roads bisecting the wetlands to allow the free flow of surface water through the
wetlands and remove all exotic invasive tree species.
19. Earthen barricades across tidal channels in the Bitou Arm: Completely remove all
earthen barricades to restore connectivity on the supratidal marsh. Maintain
freshwater flow from northern sections into the supratidal marsh south of the R340.
20. Middle reaches of the Bitou Estuary: Remove all exotic tree species from this area,
allow the artificial canal to naturally silt up, allow salt marsh to naturally re-colonise
the extensive Stenotaphrum grasslands, insert culverts below the road bisecting the
floodplain to link up the old channels.
21. Old Cape Road canal: Increase the width and depth of the canal dug through the old
Cape Road embankment (to the south of the old Cape Road pillars in the water).
Increasing the size of that canal will facilitate flushing of the Bitou (cut out the S
bend).
22. Development of an Estuary Management Plan: It is also recommended that an
Estuary Management Plan (EMP) be developed for the Keurbooms Estuary (includes
Bitou Estuary) following the guidelines developed for the estuaries of the Cape Floral
Region. The development of an EMP would provide a framework for evaluating the
proposed mitigation measures for improving the health of the estuary and the
feasibility of their achievement. The management plan would also assist in allocating
roles and responsibilities to all authorities managing activities in and around the
system, as the current impacts on the estuary are managed by various spheres of
government ranging from the local (e.g. development) to the national (e.g. fishing)
level.
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It is essential that the non-flow related recommendations given in the Reserve
Determination reports be captured, together with these flow objectives, in the water
resource protection sub-strategy of the catchment management strategy for this
catchment. This management plan should also address the freshwater biodiversity needs
of the catchment, where the specific flow, water quality habitat and biota objectives
necessary to meet the biodiversity targets are included. Issues should be given serious
consideration, particularly in terms of developing an EMP and improving the poor
condition of the vegetation communities (e.g. supratidal saltmarsh).
6.9 SOCIO-CULTURAL IMPORTANCE
Although the Keurbooms and Bitou Estuaries are of significant value to local inhabitants
with regard resource use and recreational pursuits, no information is presently available
on the socio-cultural importance of the freshwater systems, other than the rivers being an
important source of agricultural and domestic water supply for the region.
6.10 PRESSURES/RISKS/THREATS
Pressures currently contributing to the present state of the Keurbooms and Bitou
Estuaries, in terms of water quantity and quality issues are fishing and bait collecting
activities, human disturbance in and around the estuary (wastewater discharge;
recreational activities), structures in the intertidal and supratidal (floodplain) area and
flow reduction from the Keurbooms and Bitou catchments (abstraction and
impoundments/damsBitou Municipality 2008). Some detail is provided below:
• Reduction in river floods: As the discharge rate and frequency of river floods
become less, the erosional capacity of floods decreases, allowing unnatural sediment
build-up and impacting on habitats.
• Structures: Weirs, bridges and causeways acts as obstructions to water flow, e.g. the
N2 bridge has resulted in disturbances to large salt marsh areas.
• Wastewater discharges, e.g. dump sites, stormwater, sewage discharges: Increased development results in increased wastewaters and sewage discharges
potentially impacting on aquatic systems.
• Human exploitation, e.g. bait collection, boating, angling, floodplain developments. All the above activities may lead to potential pollution, habitat
destruction and bank erosion, including the invasion of alien tress onto floodplain
areas and reed encroachment.
• Poor land use practices in the upper catchment: Poor land management results in
increased sediment input, nutrient enrichment and pollution.
• Uncontrolled water abstraction and impoundments: Poorly managed upstream
impoundments result in altered flow regimes reaching estuaries, i.e. reduced base flow
required for ecological functioning and insufficient freshwater pulses for scouring and
mouth maintenance.
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CHAPTER 7 - CLASSIFICATION, ECONOMIC VALUE,
PROTECTION AND REHABILITATION
7.1 CLASSIFICATION13
Harrison et al. (2000) class the Keurbooms as a warm-temperate, permanently open,
medium-large, Type F barred system (supratidal barrier), whose ichthyofauna, water
quality and aesthetics are rated as good, good and moderate respectively. Overall
condition was rated as Good by Whitfield (2000) although he does remark that any major
dams in the catchment could severely impact on this status.
A recent study by Turpie and Clark (2007) ranked the Keurbooms as the 18th
most
important estuary in South Africa in terms of biodiversity with an overall importance
score of 88 out of a possible 100. This ranking was based on a detailed assessment of
both ichthy- and avifauna. They also ascribe an A/B management class to the system
based on the freshwater requirements. The Rapid Ecological Reserve Determination
(Bitou Municipality 2008) for the Keurbooms confirmed this A/B status based on an
Estuarine Health Index score of 90, which comprises a habitat health score of 94 and a
biotic health score of 87. An index score of A represents an unmodified, natural system,
while B represents a system that is largely natural with few modifications. In order to
maintain the system in the A/B class, the Rapid Reserve Determination study
recommends a scenario where abstraction or diversion of freshwater (to Plettenberg Bay)
can be increased to 0.3 m3/s from the present diversion of 0.1 m
3/s.
Coetzee et al. (1997) applied a botanical rating system to estuaries, which allowed each
system to be scored according to area covered by each plant community type, its
association with the estuary, its condition and the plant community richness (number of
species). Thirty-three estuaries were evaluated between the Olifants in the Western Cape
and the Great Kei in the Eastern Cape and the plant community types considered were
supratidal saltmarsh, intertidal saltmarsh, submerged macrophyte beds and reeds and
sedges (reedswamp). The Keurbooms Estuary was rated tied 8th
overall (5th
amongst
permanently open systems) together with the Gamtoos and Wildevoelvlei systems with a
rating score of 250 (normalised score of 61 out of 100); the top-rated estuary overall was
the Olifants with a score of 410 (normalised score of 100). Within the Southern Cape
region, the Keurbooms was rated 2nd
out of six systems with a score of 250 – Groot Brak
is rated first with a score of 290. Of the four plant community types used in the rating
system, submerged macrophytes were most important (80), followed by intertidal
saltmarsh (70), reedswamp (60) and supratidal saltmarsh (40). This rating system can be
slightly misleading as the score and ranking does not necessarily reflect the overall health
of a system but merely the state of the botanical community. It does, however provide an
indication of which estuaries should be accorded a high conservation status and be
allocated sufficient freshwater in order to maintain it present state.
13
Note that the Keurbooms refers to both the Keurbooms and Bitou Estuaries as well as the Keurbooms
lagoon.
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A modification of the botanical rating system that took functional importance, species
richness, plant community type richness and plant community type rarity into account
(Colloty et al 2001) resulted in the Keurbooms system being ranked 27th
out of 30 warm-
temperate estuaries, with a rating of 235. The top ranked warm-temperate estuary is
Knysna with a rating of 360. The Keurbooms system does not rank in the top 36 estuaries
in the country in terms of botanical importance (St Lucia is ranked No. 1).
7.2 ECONOMIC VALUE
Turpie and Clark (2007) placed the following economic values on the Keurbooms
Estuary:
Subsistence - ranked 7th
amongst temperate systems with a value of R379 006 per
annum; top ranked system is the Swartkops with a value of R808 953.
Property – ranked 10th
amongst temperate systems in terms of property value related to
estuaries with a value of R399 million; top rated is Knysna with a value of R1.4 billion;
range of property value related to all temperate estuaries is between R1 million and R2
billion; most systems fall into the R10 – 50 million range.
Tourism – ranked 2nd
amongst temperate systems in terms of tourism value attributed to
estuaries with a value of R400 million per year; top ranked is Knysna at R1 billion; total
value for all temperate systems is R2.08 billion; most are between R10 000 and R1
million although 23 estuaries have an estimated tourism value of < R10 000.
Nursery (protection of juvenile organisms) – ranked 11h amongst temperate systems
with a value of R13.8 million per annum; top value is Knysna at R167.6 million.
Existence – the Keurbooms does not rank amongst the top 40 temperate estuaries; overall
the public’s willingness to pay (WTP) for estuary conservation in SA for all income
groups is valued at R80 842 180.
7.3 PROTECTED AREA STRATEGY AND POTENTIAL
7.3.1 ESTUARY PROTECTED AREAS
The establishment of a core Estuary Protected Area (EPA) network around the South
African coastline should take into account the following goals (after Turpie and Clark
2007):
• Representativeness: all estuarine species within a bioregion should be represented in
viable numbers in the protected areas network.
• Maintenance of ecological processes: the protected area network should allow for
connectivity and interaction with other adjoining ecosystems.
• Maintenance of fishery stocks: the protected area network should provide enough
protection to exploited species that they are able to act as source areas for surrounding
exploited areas.
• Minimization of economic opportunity costs: biodiversity targets should be met at
least possible opportunity cost, through careful selection of the estuaries included in
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the protected area network. Estuaries where protection offers greatest economic
benefits or lowest economic costs should be prioritized in the EPA selection process.
• Implementabilty: consideration should be given to the practicalities of protection in
each estuary.
The biodiversity protection targets addressed in Sections 7.3.2 to 7.3.4 below address the
first three goals listed above. The final choice of estuaries that will be used as part of an
EPA network that will realize these targets will be subject to the final two goals listed
above.
7.3.2 PROTECTION OF HABITAT TYPES
Targets for the protection of estuarine habitat types (as a percentage of the total estuarine
habitat measured in hectares) have been recommended by Turpie and Clark (2007). The
percentages for habitat types found in the Keurbooms are as follows; supratidal salt
marsh (30%); intertidal salt marsh (40%); reeds and sedges (20%); sand/mud banks
(40%); submerged macrophytes (40%); and estuary channel (30%). The overall
percentage of all habitat types combined that should be protected is 30% of the total
available 25 095 hectares.
7.3.3 PROTECTION OF FISH AND BIRD SPECIES
Similarly targets for the protection of fish and bird species (as a percentage of the total
population) were set at 50% of the population of red data (threatened) species; 40% of the
population of exploited species; and 30% of the population of all other species. The
effective targets for selected individual species that are associated with the Keurbooms
are provided in Table 7.1 (after Turpie and Clark 2007). Amongst the bird species it is
only the African black oystercatcher that is a listed threatened species with the remaining
assemblage falling under the 30% protection target. Amongst the fish it is only the
Knysna seahorse that is endangered, and all fish assumed to feature prominently in
fishermen’s catches, such as dusky kob, spotted grunter, white steenbras and bait species
such as mullet are targeted for 40% protection of the population.
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Table 7.1 Target percentages for the protection of selected estuarine fish and bird species
(after Turpie and Clark 2007).
7.3.4 PROTECTION OF ECOSYSTEM AND LANDSCAPE-LEVEL PROCESSES
The protection of habitat types and associated fauna in estuaries may only be considered
effective if the populations benefiting from these measures are viable, that is to say that
they are sufficiently large and there is a degree of overlap between protected
areas/populations to ensure the maintenance of genetic integrity and evolutionary
processes. In order to achieve this, Turpie and Clark (2007) recommended the following
measures which would also serve to help maintain landscape-level processes that
maintain ecological integrity at a large scale (relevance to the Keurbooms estuary is also
provided:
• Viability: EPAs should protect a minimum of 33% of each habitat within an estuary
as a no take sanctuary. Although this may not be a realistic measure it is potentially
attainable due to the large size of the estuary and extent of individual habitats.
FISH SPECIES TARGET % BIRD SPECIES TARGET %
Acanthopagrus berda 30 White-breasted Cormorant 30
Anguilla mossambica 30 African Black Oystercatcher 50
Argyrosomus japonicus 40 Common Ringed Plover 30
Atherina breviceps 30 White-fronted Plover 30
Caffrogobius gilchristi 30 Grey Plover 30
Caffrogobius nudiceps 30 Terek Sandpiper 30
Diplodus sargus capensis 40 Common Sandpiper 30
Elops machnata 40 Curlew Sandpiper 30
Galeichthys feliceps 40 Common Greenshank 30
Gilchristella aestuaria 30 Red Knot 30
Heteromycteris capensis 30 Little Stint 30
Hippocampus capensis 50 Sanderling 30
Lichia amia 40 Bar-tailed Godwit 30
Lithognathus lithognathus 40 Eurasian Curlew 30
Liza dumerilii 40 Common Whimbrel 30
Liza richardsonii 40 Pied Avocet 30
Liza tricuspidens 40 Black-winged Stilt 30
Monodactylus falciformis 30 Kelp Gull 30
Mugil cephalus 40 Caspian Tern 30
Myxus capensis 40 Swift Tern 30
Pomadasys commersonnii 40 Sandwich Tern 30
Pomatomus saltatrix 40 Common Tern 30
Psammogobius knysnaensis 30 Little Tern 30
Rhabdosargus holubi 40
Sarpa salpa 40
Solea bleekeri 30
Syngnathus temminckii 30
Torpedo sinuspersici 30
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• Viability: Systems in an unacceptable state of health should be excluded, particularly
canalized systems. The Keurbooms is in a fair state of health according to Whitfield
(2000) and enjoys a high biodiversity importance rating of 92, placing it in 11th
position amongst the country’s estuaries.
• Connectivity: There should be a relatively even distribution of protected estuarine
area around the coast. A network of EPAs has yet to be set up and it is not known
how the Keurbooms would feature in this arrangement.
• Landscape level processes: Estuaries adjoining terrestrial or marine protected areas
will be prioritized in the selection process, and those adjoining undeveloped land
should be prioritized over those that are developed. There is not much undeveloped
land in the lower and middle reaches of the estuaries although the upper reaches
represent relatively pristine areas.
• Viability, ecosystem processes, evolutionary processes and representativeness: Large
open systems should be prioritized over smaller systems but a range of different sized
estuaries should nevertheless be represented. The Keurbooms is a medium/large open
system.
• Efficiency: Systems with higher conservation importance scores should be given
greater priority. The Keurbooms has a high score (92) in this regard.
7.3.5 TYPE OR LEVEL OF PROTECTION
The study by Turpie and Clark (2007) concluded that in order for conservation targets
and goals to be achieved, 80% of temperate estuaries needed some form of partial
protection rather than a few with total protection; in many instances this was because the
benefits of partial protection were seen to outweigh the management and opportunity
costs. Furthermore it became apparent that a greater level of protection of estuaries would
be desirable from a socio-economic perspective than would be necessary just in order to
meet biodiversity conservation targets. The partial protection of 80% of estuaries was
also deemed desirable from a management perspective, in that it would facilitate the
introduction of an almost universal sanctuary zone in each estuary, which is marked by
standard markers, which in turn would facilitate public awareness about the estuarine
protection system.
Initial guidelines for the conservation of estuarine biodiversity (Turpie 2004) required
that estuaries be assigned to one of three categories, namely:
• Estuary Protected Areas (EPAs) - part or all of an estuary is a sanctuary, providing
protection from consumptive use; state-run; selected with both biodiversity
representation and socio-economic considerations in mind;
• Estuary Conservation Areas (ECAs) - co-managed estuaries in which general
regulations are augmented by estuary-specific regulations; initiated by local
communities through estuary forums which would also design zonation schemes and
bylaws; likened to the role of private nature reserves and conservancies in the
protection of terrestrial biodiversity, and are generally not considered to contribute to
protected area conservation targets because their contribution to conservation is less
secure in the long term; and
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• Estuary Management Areas (EMAs) - to which general regulations apply; at least
must have a management plan in order to facilitate compliance with general
regulation and maintain estuarine health at an acceptable level.
However, due to complications that arise between fully and partially protected systems
with respect to national legislation and the subsequent administration of EPAs and ECAs
it has been recommended that the above categories be scrapped and that zonation be used
instead as a general strategy in the management of estuaries (Turpie and Clark 2007).
Essentially this means that the estuaries selected to form part of an overall protection
network should contain a sanctuary zone and should receive sufficient protection and
sufficient quantity and quality of freshwater inflows to be maintained in an appropriate
state of health.
The zonation strategy means that individual estuaries may contain a fully protected
(sanctuary) area, which would include terrestrial margins, and a conservation area that
would be zoned according to the vision and objectives/requirements for that estuary.
Sanctuary areas would fulfill the same function as an EPA and as such would have to be
set up and managed by an organ of the state. Conservation areas may be managed by a
wide variety of styles within a co-management setup where the community and an
estuary management forum are the main role players. By adopting a system like this on
all selected estuaries, it is likely to be easier and more efficient to manage the entire
network, especially if similar rules apply and similar markers and mapping styles are
used in all estuaries to denote sanctuaries and other types of use zones (Turpie and Clark
2007).
7.3.6 THE KEURBOOMS IN PERSPECTIVE
Based on the findings of Turpie and Clark (2007), the following can be said about the
Keurbooms/Bitou estuaries with regards to requirements in terms of protection:
• The Keurbooms is one of the core set of temperate estuaries required to meet the
targets for biodiversity protection of estuarine resources; scores (out of 100) that
contributed to the overall rating of 88 for the Keurbooms were size (100), habitat
importance (90), zonal type rarity (20) and biodiversity importance (95).
• Targets for the protection of habitat types (as a percentage of the total estuarine
habitat measured in hectares) are as follows; supratidal salt marsh (30%); intertidal
salt marsh (40%); reeds and sedges (20%); sand/mud banks (40%); submerged
macrophytes (40%); and estuary channel (30%). The overall percentage of all habitat
types combined that should be protected is 30% of the total available 25 095 hectares.
• The recommended extent of undeveloped margin is 50% (an average score for public
perception of optimal level of development around SA estuaries was 40%).
• The recommended minimum water requirement falls under the A/B management
class, which means a high priority and requirement and the priority for rehabilitation
is HIGH.
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7.4 RESTORATION/REHABILITATION
A workshop attended by estuarine scientists and managers was held to determine which
temperate estuaries should be prioritized for rehabilitation (see Turpie and Clark 2007)
and which issues should be addressed in each estuary. A total of 50% of temperate
estuaries were considered to be in need of some form of rehabilitation; these included
systems ranging from a poor to excellent state of health. Thirty-nine estuaries, including
the Keurbooms, were given a HIGH priority status for rehabilitation. According to the
consensus opinion at the workshop the single requirement for rehabilitation on the
Keurbooms Estuary is clearing of alien vegetation. Interestingly there is no mention of
restoration of areas that have undergone inappropriate bank stabilization, but the report
pre-dates the 2007 floods that caused extensive damage and resulted in large areas of the
banks in the lower-reaches being stabilized by property owners. There is also no mention
of the rehabilitation of the Bitou wetlands, which is seen as a priority by this report; this
can be accomplished in cooperation with landowners and Non-Governmental
Organizations (NGOs) such as Working for Wetlands.
7.5 CLIMATE CHANGE
There are several threats associated with climate change that are of particular relevance to
estuaries, their users and the surrounding area (DEADP 2007). These include decreased
rainfall (drought), increased rainfall and frequency of freshwater floods, increased water
temperature (marine/estuary), sea-level rise and increased frequency and intensity of
storm events. These are all relevant to the Keurbooms/Bitou area as drought can affect
farmers and the availability of the ecological reserve, flooding events can be devastating
in the area, increased temperature affects the survival and distribution of species and sea-
level rise and storm events pose a threat to landowners and infrastructure, either on their
own or when occurring together.
Although already referred to in Section 4.4.3, we again stress that the Western Cape
PSDF takes climate change into account and categorically states that:
“No further urban development shall be permitted on open coast lines that are
vulnerable to erosion, inlets that are susceptible to increased storm activity, river
banks that are liable to flooding, coastal buffer zones and ecological setback lines in
estuaries and below the 1:50 year floodlines (erven) and the 1:100 year floodline
(building platform).”
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CHAPTER 8 - THE WAY FORWARD: OBJECTIVE II
8.1 LOCAL ESTUARY MANAGEMENT FORUM
Objective II involves the process of formulating an Estuary Management Plan (EMP) for
the Keurbooms and Bitou Estuaries (inclusive of the lagoon area). This will be achieved
through a workshop aimed at obtaining stakeholder input with regards aspects such as the
vision, strategic objectives, management action plans and zonation plan. Ideally the EMP
should be developed with the help of a constituted local management institution, which
represents all the relevant stakeholders and their interests. This management institution
would take the form of an Estuary Management Forum (EMF) and would comprise the
following (van Niekerk and Taljaard 2007):
• A chairperson, to be elected by the forum and to take the lead in the development and
implementation of the local EMP.
• Technical Working Groups for each of the following key result areas:
− Biodiversity conservation;
− Exploitation of living resources;
− Land-use and infrastructure development;
− Water quantity and quality;
− Institutional and management structures
− Tourism;
− Sustainable livelihoods; and
− Education and awareness
• The forum itself comprising all stakeholders.
The Technical Working Groups should ideally include representatives from the
authorities who have a mandate and executive powers within the specific sector (e.g.
conservation; water quality) as well as competent natural or social science specialists
acting in an advisory role. It is likely that CapeNature will be the lead authority.
Because the Keurbooms does not possess a management forum at present, Enviro-Fish
Africa are fulfilling the role of developing and initiating the implementation of the EMP
and will make recommendations that a constituted forum be set up to ensure the long-term
implementation and monitoring of the EMP.
8.2 THE ESTUARY MANAGEMENT PLAN
Key to the formulation of an EMP will be the organization of a stakeholder workshop in
order to develop a vision and objectives for the Keurbooms and Bitou systems based on
the Situation Assessment (this report) and the future needs and desires of the
stakeholders. These outcomes together with the assessment provided by Turpie and Clark
(2007; Chapter 7), the rapid reserve determination study (Bitou Municipality 2008) and
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the C.A.P.E. Generic Framework for EMPs (van Niekerk and Taljaard 2007) will be used
to formulate the EMP.
Essentially the following tasks will be performed for Objective II:
• Assist in setting a Vision and Strategic Objectives for the Keurbooms and Bitou
Estuaries.
• Develop a range of Management Strategies to achieve the Vision and Objectives.
• Prepare an Estuary Zonation Plan (EZP) and Operational Objectives based on the
above.
• Identify Management Action Plans (MAPs) to achieve all strategies and operational
objectives including implementation procedures (includes human and financial
resources).
• Propose an institutional structure (i.e. the EMF) to guide the implementation of the
EMP.
• Develop a monitoring and evaluation programme including a description of a process
for reviewing the management plans.
• Identify research priorities.
8.3 THE STAKEHOLDER WORKSHOP
The workshop will concentrate on the development of a vision, strategic objectives and
zonation plan and will also need to address the prioritization of issues.
In order to provide stakeholders attending the workshop with some idea of what to
expect, some useful background information is supplied in the sections below.
8.3.1 VISION
The Vision for the estuary should be inspirational, representing a higher-level statement
of strategic intent, while taking into account the Vision set for all estuaries within the
greater Cape Floristic Region.
One should also consider including a reference to the desired Category for the systems as
this will, in most instances, determine the strategic objectives and management actions
required to achieve the Vision. For example, if the Vision contains a reference to
ensuring that the estuaries are maintained at a Category A or B level, this implies that
certain water quality and quantity objectives need to be met.
Vision for Estuaries in the CFR: Our estuaries are beautiful, rich in plants and animals, they
attract visitors, sustain our livelihoods and uplift our spirits
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8.3.2 STRATEGIC OBJECTIVES
The strategic objectives are generally qualitative statements of the values defined in the
vision and should be statements of outcomes rather than means of achievement. For
example, if the Vision refers to a “beautiful estuary”, then the strategic objectives for the
relevant key result areas need to reflect aspects such as clean water, rehabilitation of
banks and no development within the 1:100-year floodline. For the Keurbooms/Bitou, the
strategic objectives proposed for the larger CFR (see text box below) need to be
considered and can provide inspiration for the setting of estuary specific objectives.
Strategic Objectives for the Estuaries of the CFR include:
Living resources: Achieve targets for ecosystem biodiversity and health in terms of
the long-term habitat persistence of habitats, species, community structure, biomass
and functioning by 2015.
Water quantity and quality: Determine, implement, monitor and review Resource
Quality Objectives (RQOs) (taking into account public health) in order to maintain
or restore estuarine structure and function in the best attainable state for five priority
estuaries within the CFR by 2010.
Land-use and infrastructure planning: Define estuarine areas, assess their current
status and values and formulate appropriate integrated management plans to
regulate development and other activities impacting upon them, with particular
reference to cumulative impacts, by 2008 (focusing on mechanisms).
Institutional and management structures: Cooperatively manage estuaries, through
relevant institutions of management comprising appropriate spheres of government
and civil society, according to appropriate management plans by 2010.
Climate change: Minimise the detrimental impacts of predicted climate change by
2010 through:
1) Taking a long-term precautionary approach to infrastructure development and
water-resource planning;
2) Influencing land management in upper and middle catchments to reduce
impacts on estuaries; and
3) Promoting long-term sustainable livelihoods through estuarine management
that minimises risks.
Education and awareness: Generate education and awareness regarding CFR
estuaries by 2010, having:
1) Contributed to integrated, collaborative and informed action and decision
making regarding estuaries;
2) Contributed to a sustainable quality of life;
3) Promoted good management practices that will sustain healthy estuarine
functioning;
4) Raised awareness of the intrinsic value of estuaries and developed a sense of
ownership of estuaries not only among local communities but throughout South
Africa; and
5) Raised awareness of and insight into the legal context and obligations of all
levels of government (national, provincial, local and community).
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The developed Vision and Strategic Objectives for the Keurbooms/Bitou may not conflict
with those developed for the CFR. Strategic Objectives for specific systems should be
listed in priority order to guide subsequent management decisions. The Strategic
Objectives must form the foundation for quantitative, operational objectives. Obviously
some of the timeframes listed in the CFR Strategic Objectives have already not been met
and would need to be revised.
8.3.3 MANAGEMENT STRATEGIES
The Vision and Strategic Objectives may be achievable through various management
strategies and these will be investigated and evaluated so as to optimally utilize financial
and human resources. Existing institutional management strategies must be incorporated
where appropriate. Before finalization of an EZP and the development of the operational
objectives, the different management strategies may have to be refined through
collaboration with stakeholders; this will be addressed during the course of the workshop
8.3.4 ZONATION PLANS AND OPERATIONAL OBJECTIVES
Once management strategies have been agreed upon, these will need to be translated into
an EZP and Operational Objectives. The EZP will be in the form of a map that clearly
demarcates the following:
• Geographical boundaries;
• Conservation/Protected zones as well as degree or class of protection needed;
• Zones demarcated for the exploitation of living marine resources (e.g. fishing and bait
collection);
• Important bio-physical features (open channel areas, Macrophyte beds, invertebrate
beds, mud banks, sand banks, wetlands, salt marshes, indigenous vegetation etc);
• Areas earmarked for rehabilitation;
• Land-use and planning provisions of surrounding areas;
• Infrastructure (e.g. roads, bridges);
• Cultural and heritage sites;
• Existing recreational and cultural activities (e.g. swimming, skiing, traditional
ceremonies etc);
• Wastewater discharges (sewage, industrial)
The Operational Objectives and Management Action Plans required to achieve these
objectives will be addressed subsequent to the workshop as will the implementation plan,
monitoring and evaluation programme. A draft EMP report will be circulated to all
stakeholders for comment prior to finalization of the report, which will be presented at
another workshop at the start of the Implementation Phase.
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8.4 ISSUES RAISED BY STAKEHOLDERS
The following issues were identified during stakeholder meetings. These will be
addressed in the EMP and do not appear in any particular order:
• An improved zonation plan is required (includes indication of floodlines, wake-free
and skiing zones).
• Estuary-specific by-laws are urgently required so that issues such as houseboats and
wake-free zones can be enforced. Speeding boats below the N2 bridges are a threat to
safety and interfere with other recreational activities such as fishing. Area above N2
bridge on Keurbooms is covered by Keurbooms Nature Reserve and enforced by
CapeNature Ordinance.
• Wake-free zones need to be indicated as such and NOT as 10 kph.
• Implementation of the Ecological Reserve.
• Alien vegetation clearing, both in the catchment and within estuary area.
• Contaminated freshwater runoff from farmlands and commercial forestry plantations.
• Conservation of wetlands (includes saltmarsh) associated with both systems.
• Compliance monitoring needs to be improved.
• Water licensing and use (abstraction) needs to conform to Reserve Determination
recommendations.
• Sewage pump stations on eastern side of Keurbooms cannot cope with peak season
loads.
• Incorporation of 1:100-year floodline in zonation to restrict irresponsible
development.
• Consider making the Bird Sanctuary a no-go area to reduce disturbance.
• General monitoring of water quality, particularly at sites where sewage may enter the
system (e.g. Rietvlei and Gansvlei areas).
• A Municipal environmental officer is required.
• More stringent control over bait collecting activities (includes illegal selling).
• The availability of recreational fishing permits over the weekend was viewed as
problematic and could impact on tourism.
• Threatened species such as the Knysna seahorse and pansy shell and their preferred
habitat need to be protected (adjacent to the Keurbooms Lagoon Caravan Park for
pansy shells and in the region of the confluence for the Knysna seahorse).
• Time taken to obtain authorization to carry out rehabilitation after floods is excessive
and leads to illegal activities; process needs to be streamlined and a standardized
approach adopted to cover instances of repeated damage after each flood event.
• No fishing competitions.
• Education and awareness programmes need to be initiated (regulations, importance of
estuaries etc.). Adopt an approach of education before issuing of fines.
• Abandoned hake long-line vessels on the Keurbooms need to be removed (safety and
possible pollution source).
• Impact of a possible desalination plant.
• Reinstate financial assistance from the Municipality to help with CapeNature’s
management actions outside of the Nature Reserve.
• Additional field rangers (two) required so CapeNature can operate effectively.
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• Investigate feasibility of making funds from boat licenses available for management
actions.
• Compliance of CapeNature personnel with skippers’ license requirements.
• Feasibility and impact of dredging to deal with excessive sediment loads.
• The proposed N2 bypass route through the lower reaches (SANRAL) needs to be
considered.
• Impact of a major dam in the Keurbooms and/or Bitou catchment.
• All management interventions that affect landowners need to be a part of a public
participation process, i.e. cooperative and not prescriptive.
• Feasibility of off-stream storage of excess flood waters to offset shortages during
times of drought.
• Clearing of debris (from alien clearing) in the catchment to reduce damages from
floods.
• Feasibility of landowners undertaking alien clearing (using own labour) as long as
funding is made available.
• Clearly indicate which government departments are responsible (mandated) for which
management interventions.
• Need to highlight the Keurbooms as a unique tourist attraction (e.g. same as
Robberg).
• Investigate additional activities that can add to attraction of the Keurbooms as a
tourist destination (e.g. hiking trails and sporting events).
• Bank erosion, from clearing of aliens, is an issue in the upper Keurbooms catchment.
• Capacity of Bitou sewerage treatment works to cope with increased development.
• Government involvement is required in the long term to ensure implementation.
• The issue of kite surfers needs to be addressed, as they do not need to pay fees like
boat owners do and yet they are a significant user group that pose a safety risk.
• The management and registration of private slipways.
• There is a potential threat of large houseboats – this is both a carrying capacity issue
and a water quality issue due to the waste they will produce.
• The culverts under roads in the wetland areas need to be cleared, and additional ones
are required to restore flow.
• A cooperative plan to address flood damage was developed in the past but has not
been implemented (a process is currently underway to determine the best approach in
conjunction with DEADP and a specialist engineer from Dept. Agriculture).
• Access to the sea in the Keurboomstrand area is a problem for non-residents (access
in other areas appears to be OK).
• Monitoring programmes must include the rivers and not just the estuaries.
• The number of business licenses to operate on the estuary (and procedure for
application and granting of licenses).
In addition to the above, the some of the mitigation measures recommended by the
Reserve Determination study (see Section 6.8.5) will be included in the EMP.
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APPENDIX I
CWAC counts for the Keurbooms River Estuary from 1997 to 2009 showing species
and total number (left) and count dates and overall total number of birds (right)
Species Total No. Count Date Total No.
African Black Oystercatcher 503 7/29/1995 1106
African Darter 44 1/21/1996 1695
African Fish-Eagle 24 7/20/1996 1365
African Sacred (Sacred) Ibis 1200 1/25/1997 2072
African Spoonbill 314 7/24/1997 857
Bar-tailed Godwit 34 2/3/1998 639
Black-headed Heron 6 8/13/1998 824
Black-necked Grebe 88 2/3/1999 1118
Blacksmith Lapwing (Plover) 214 7/13/1999 668
Black-winged Stilt 57 2/10/2000 625
Cape Cormorant 462 7/14/2000 697
Cape Shoveler 2 7/26/2001 1027
Cape Teal 20 2/5/2002 1569
Cape Wagtail 129 7/25/2002 664
Caspian Tern 30 1/17/2003 997
Cattle Egret 9 7/11/2003 561
Common (Whimbrel) Whimbrel 1070 1/23/2004 1112
Common Greenshank 753 4/6/2004 737
Common Moorhen 1 7/14/2004 726
Common Ringed Plover 418 1/24/2005 1519
Common Sandpiper 52 5/9/2005 719
Common Tern 611 7/22/2005 997
Curlew Sandpiper 1586 1/27/2006 1087
Egyptian Goose 423 7/10/2006 1314
Eurasian (Curlew) Curlew 18 1/18/2007 1104
Giant Kingfisher 12 8/10/2007 823
Great Crested Grebe 2 2/5/2008 1312
Greater Flamingo 43 7/14/2008 1163
Grey (Black-bellied) Plover 1932 2/23/2009 1133
Grey Heron 179 7/22/2009 821
Grey-headed Gull 2 Total Number 31051
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APPENDIX I (continued)
Hadeda Ibis 35
Half-collared Kingfisher 5
Hybrid Duck 3
Kelp Gull 9183
Kittlitz's Plover 12
Lesser Flamingo 9
Little Egret 563
Little Grebe (Dabchick) 917
Little Stint 12
Mallard 61
Marsh Sandpiper 118
Osprey 8
Pied (Avocet) Avocet 254
Pied Kingfisher 112
Purple Heron 83
Red Knot 7
Red-billed Teal (Duck) 9
Red-knobbed Coot 1
Reed (Long-tailed) Cormorant 1850
Ruddy Turnstone 4
Ruff 3
Sanderling 2
Sandwich Tern 757
Spur-winged Goose 3
Swift (Great Crested) Tern 4953
Three-banded Plover 22
Unidentified Terns 325
Water Thick-knee (Dikkop) 220
White-breasted (Great) Cormorant 588
White-fronted Plover 622
Wood Sandpiper 42
Yellow-billed (Intermediate) Egret 1
Yellow-billed Duck 29
Total Number 31051
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APPENDIX II Reserve determinations conducted for the Keurbooms/Bitou quaternary catchments.
♣: Ecological Reserve + Basic Human Needs Reserve (BHNR).
♦: Low to very low confidence. The EWR at the outlet of quaternary catchment K60C is based on the natural flow of that specific catchment only
and does not include the flow contribution from upstream catchment.
♣: Ecological Reserve + Basic Human Needs Reserve (BHNR).
♦: Low to very low confidence. The EWR at the outlet of quaternary catchment K60C is based on the natural flow of that specific catchment only
and does not include the flow contribution from upstream catchment.
Quaternary
catchment River
Level of
Reserve
Quality /
quantity
Date template
signed by CD:
RDM
Notes PES EIS REC
% MAR
Ecological
Reserve
% MAR ♣
Surface
water
Reserve
(MCM/a)
vMAR
(MCM)
K60C Keurbooms Desktop ♦ Quantity 13/03/02 Incremental at the
outlet of quaternary
catchment K60C.
B Very
high
A 49.6 49.6 9.812 19.78
K60D Keurbooms Rapid III Quantity 14/08/07 Cumulative at the
outlet of quaternary
catchment K60D.
B Very
high
B 33.6 33.601 48.238 143.56
K60E Keurbooms Rapid III Quantity 14/08/07 Cumulative at the
outlet of quaternary
catchment K60E.
B Very
high
B 33.6 33.602 54.656 162.66
K60F Bitou Rapid III Quantity 10/03/06 Cumulative at EWR
Site 3. B Very
high
B 33.6 33.830 12.422 36.72