appendix e - · pdf fileannual stream bank assessment . ... stream cover, bank stability and...

West Australian Landfill Services 2011 SRL Annual Monitoring Report Revision 01

Appendix E Annual Stream Bank Assessment

West Australian Landfill Services, South Cardup Landfill Annual Stream Bank Assessment November 2011

1 GHEMS Revegetation – Environmental

© GHEMS Holdings Pty Ltd.

GHEMS Holdings Pty Ltd

ABN 49 913 468 699 4 Duffy Street, Bassendean

Western Australia 6054

Ph: +61 8 9373 7100

Fax: +61 8 9373 7111

E-mail: [email protected]

Internet: www.ghems.com.au

Disclaimer

This report has been produced by GHEMS Holdings Pty Ltd solely for the benefit of Western Australian Landfill Services.

GHEMS Holdings Pty Ltd shall resume no liability or

responsibility to any third party arising out of the use of or reliance upon this document by any third party.

This document may not be reproduced or copied in the whole or part without the express written consent of GHEMS Holdings Pty

Ltd and Western Australian Landfill Services.

mailto:[email protected]



Contents

1. INTRODUCTION…………………………………………………………..…..........3

2. HYDROLOGY………………………………………………………………..……....4

3. STREAM BANK ASSESSMENT METHADOLOGY……………………..……...4

4. CURRENT STREAM BANK CONDITION……………………………..…………5

4.1 Vegetation Condition …………………………………………………..….……..5 4.2 Stream Bank Condition ………………………………………………..….……..6 4.3 Stream Environmental Rating ………………………………………..…….…..7

5. CURRENT IMPACTS DUE TO LANDFILL……………………………..………..8

6. IMPACTS DUE TO CURRENT LAND MANAGEMENT PRACTICES

IN ADJACENT FARMLAND……………………………………….………..……..8

7. WATER QUALITY MONITORING…………………………………………..…….8 7.1 pH levels…………………………………………………………………....…..9 7.2 Total Dissolved Solids (TDS)……………………………….……………....10 7.3 Total Suspended Solids (TSS)…………………………….…………….….11 7.4 Ammonium and Conductivity……………………………….……………...12 7.5 Leachate Spill………………………………………………………………….12

8. ACTIONS TAKEN IN RESPONSE TO PREVIOUS

RECOMMENDATIONS…………………………………………………….……….13

9. RECOMMENDATIONS FROM CURRENT ASSESSMENT……….…………..13

10. CONCLUSIONS……………………………………………………………………..14

11. STREAM BANK ASSESSMENT PHOTOS…………………………..……….…16

12. REFERENCES……………………………………………………………..…….….19

APPENDIX 1: SOUTH CARDUP LANDFILL SITE…………………….….……20 APPENDIX 2: FORESHORE CONDITION ASSESSMENT REPORT (WRC, 1999)……………………………………………..…….…..22 APPENDIX 3: ELEMENT OF THE FORESHORE CONDITION ASSESSMENT SYSTEM (WRC, 1999)………………………...27 APPENDIX 4: WATER QUALITY DATA……………………………….…….….34



INTRODUCTION

South Cardup Landfill (SCL) facility is located at the base of the Darling Scarp approximately 45

kilometres south of Perth and 4.5 kilometres south of Byford along the South Western Highway.

SCL is a Class II Landfill site owned and operated by West Australian Landfill Services (WALS). It is

used as a secure containment facility for the disposal of inert, putrescible and low level commercial

and industrial wastes and employs strictly controlled landfill practices (WALS, 2004).

The purpose of this report is to outline any impacts that landfill activities may be having on the banks

of an intermittent stream (the stream) that runs through the Landfill facility. The section of the stream

west of the bottom storage dam forms the focus of this assessment (Figure 1). Rainfall data and

water quality data including pH, TDS (Total Dissolved Solids), TSS (Total Suspended Solids),

ammonium and conductivity were provided by WALS. A brief assessment on how these may affect

the stream system has been included.

GHEMS Holdings Pty Ltd. (GHEMS) has been employed by WALS to prepare an assessment of

stream condition including vegetation and bank condition, water quality analysis and identification of

items requiring action. A site visit was conducted by GHEMS consultants Matthew Blacklow and

Tyson Anderson, on 30 November 2011, and follows prior assessment of the site on 15 December

2010.

Figure 1: Survey area



2. HYDROLOGY

The stream runs through the valley in which the South Cardup landfill facility has been developed

and forms a part of the lower Serpentine River Catchment Area. It is a sub-catchment of the Peel –

Harvey Catchment. During normal flow periods the stream dissipates into sediments on the Swan

Coastal Plain (URS, 2000). During periods of peak flow (generally in late winter) the stream

discharges into the Cardup Brook (URS, 2000) just north of its confluence with Manjedal Brook.

From here the creek system then becomes an engineered drain which discharges into the Peel Main

Drain which in turn discharges into the Serpentine River.

The natural course of the stream through the landfill site has been altered through a series of

deviation drains which channel water around the landfill site. The deviation drain system includes a

number of dams. The stormwater drain system includes 4 dams (a surge dam, a retention dam, a

large sedimentation dam and a storage dam). The storage dam which is the last dam the stream

runs into before it leaves the landfill site forms the eastern boundary of the assessment area.

3. STREAM BANK ASSESSMENT METHODOLOGY

A visual assessment of stream banks within the Landfill lease and the adjoining pastoral property

was undertaken (Figure 1) following methods in the Waters and Rivers Commission: Foreshore

Condition Assessment (WRC, 1999).

Both banks of the stream were traversed between the lower storage dam and the South Western

Highway. Observations were made of the stream bank condition including aquatic and fringing

vegetation condition, species diversity, stream cover, bank stability and level of sedimentation. In

addition surrounding landuse impacting on or likely to impact on the stream and fringing vegetation

were considered. By combining the stream bank assessment and assessment of surrounding

landuse an overall stream environmnetal rating was calculated with a rating of ‘Excellent’ denoting a

pristine streamline with no erosion or weed invasion to ‘Very Poor’ denoting a highly cleared and

modified streamline with significant erosion and weed invasion.

Observations of the following were also recorded: condition of riparian vegetation, bank steepness,

vegetation health, soil and level of soil cohesion, and level of protection e.g. fencing and stock

access. The soil type constituting the stream bank denotes the general soil cohesion properties and

hence the potential for erosion. Rock or stone is rated as ‘Excellent’, clay-loams are rated as ‘Good’

and sand/loose loam is rated as ‘Poor’. Notes were also made on the species of native flora present

on site and species of weeds present on site in addition to the level of invasion by these species

In addition to the Waters and Rivers Commission: Foreshore Condition Assessment (WRC, 1999),

vegetation on site was also rated using the Vegetation Condition Scale used by Keighery (1994).



Results of the current stream condition analysis were compared with results from the last

assessment conducted 10 November 2009. Comparison highlighted any negative effects the SCL

site was having on water quality within the stream and if remedial actions were working.

4. CURRENT STREAM BANK CONDITION

4.1 Vegetation Condition

The vegetation condition within the survey area was assessed (Nov, 2011), as B3 (Degraded) for the

bottom storage dam and enclosed WALS area west of the access road. This rating was assigned to

this assessment using the methods described in WRC, 1999 (see Appendix 3).

Natives including Melaleuca incana, Regilia ciliate, Acacia pulchella, Eucalyptus rudis and Juncas

spp are the dominant species occurring around the bottom dam area and the area west of the

access road, with many setting seed. They appear to be in good health with no signs of death,

disease or insect damage. Natural regeneration was also evident with several Acacia pulchella,

Eucalyptus rudis and Corymbia callophylla saplings noted. Typha orientalis was still present,

however its dominance compared with previous years has decreased. A thick rush bed situated

between the top and bottom storage dams acts as a filter reducing the amount of nutrients and

pollutants present within the creek system.

Weeds including Perennial Veldt Grass (Ehrharta calycina) and Kikuyu (Pennisetum clandestinum)

are the dominant understory plants throughout the bottom storage dam area and area west of the

WALS access road. This can be easily mitigated with ongoing weed control practices at correct

times. However if weed control practices are not maintained then the dominance and spread of these

species could continue and undermine further rehabilitation practices. Cotton Bush (Gomphocarpus

fruticosus), Paterson’s curse (Echium plantagnieum) and Deadly Nightshade (Solanum nigrum) are

listed as declared weeds by the department of Agriculture (DAFA, 2009). These species have been

targeted in weed removal operations and this has resulted in a minimal presence, however adjacent

land is heavily infested with these species, in particular cottonbush. Given the proximity of the

adjacent land there is a high risk of re-colonisation. Ruby Dock (Acetosa vesicaria) was also noted

but its presence was minimal. This demonstrates the ability for weeds to re-colonise areas as Ruby

Dock was mostly absent from the reporting area in the previous year. This also highlights the

importance of maintaining a stringent weed control program.

These are the main contributing factors for the B3 rating given to this area. However with sustained

recruitment understory and shrub species should, over time, act to further stabalise the banks and

reduce weed cover by competing for available light, nutrients and other limiting factors. Coupled with

continued management of the area a future rating of B2 or B1 is achievable. The overall

environmental rating however, remains unchanged and stands at 21 (MODERATE), indicating a

slight decrease from the previous year, although this is largely due to a reduction in bank stability

and increased sediment rather than vegetation condition.

In conjunction with this survey, the lower stream, running between the western boundary fence of the

WALS property lease and the South-West Highway, was also assessed.



This area is on private land, and outside of the environmental responsibility of WALS. The

assessment found that the condition of the stream and surrounding vegetation was rated as C1

(Eroding or Erosion Prone) as per previous years. The area is dominated by weed species, with only

remnant Eucalyptus spp and localized populations of native sedges remaining. Thick, established

stands of Cotton bush were recorded along large sections and are severely impacting the

environmental values of the area, as well as providing a seed source for further infestations within

the WALS landholdings. There was much evidence of livestock activity, with associated damage to

stream bank structure, including crossing points, mud wallows and trampling of banks and

vegetation. There are very few Eucalypt seedlings/saplings, and these species are unlikely to be

able to regenerate sustainably without environmental management practices being implemented.

The overall environmental rating stands at 8 (VERY POOR), a figure that has been decreasing

gradually on a yearly basis and which appears to be getting worse. Points were lost in areas relating

to stream cover and bank stability, and can be directly related to ongoing disturbance from

unrestricted livestock access and washouts. As previously mentioned, this stream is located on

private property, and its condition cannot in any way be attributed to WALS activities or

management.

4.2 Stream Bank Condition

Stream bank slopes ranged from ‘Moderate’ (10-45°) to ‘Steep’ (45-60°) within the WALS site. The

majority of banks were of ‘Moderate’ steepness with approximately 10m of bank on the far west of

the site near the private property boundary fence being ranked as ‘Very Steep’(>60°).

Bank subsidence was noted to have increased since the last survey was undertaken, in particular

the area between ponds 1 and 2 (Appendix 2) in the area west of the access road. There are also

several new points of minor undercutting and this could further undermine bank stability in the future.

It was reported that for a period during 2010 water was cut off from entering the bottom dam as

water requirements for WALS operations increased, this may have contributed to some erosion as a

lack of permanent water can reduce soil stability. A sudden influx of water into the bottom dam can

lead to water moving at a higher velocity through the bottom dam and into the creek, removing

surface sediment at an increased rate. Debris including branches, rubbish and leaves have also

significantly reduced water flow into some areas, resulting in buildups that have led to overflows of

large volumes of water at high velocity, causing significant disturbance to fragile areas of the bank.

The level of erosion that has occurred since the last survey gives some cause for concern given that

soil cohesion remains ‘Good’ with stream banks composed of mostly gravely clay with considerable

quantities of blue metal and granite gravel. Major stream banks around Ponds 1 and 2 are now well

bedded in and further erosion in this area is unlikely. However the stream running between ponds 1

and 2 is at a higher risk of erosion. Continued monitoring to detect any further changes in bank

stability is recommended.

The fence surrounding the bottom storage area has been repaired since the last survey and has

managed to keep livestock from the WALS site, although some parts do require maintenance.



The section of stream outside the WALS site ranges from ‘Slight’ (0-10°) to ‘Very Steep’. Areas of

undercutting noted in the previous year’s report have dramatically increased despite ‘good’ soil

cohesion with some banks now at 0 . Large sections of tree roots are now exposed decreasing the

integrity of the bank. There was also evidence that livestock have access to the site given the

crossing points, hoof prints and scats situated around the stream, which in turn could further

decrease the stability of the bank. Several large mature eucalypts were also noted to have fallen

across the stream in many cases dislodging large amounts of soil as well as reducing bank stability.

It was also noted that large sections of stream running through this property have become dammed

due to a build of debris including trees, branches, leaves etc. As a result water is building up before

overflowing with an increased velocity. These problems can be mitigated with a raft of different

solutions and include removing debris to minimise damming, reducing bank steepness as well

improving bank stability however this not the responsibility of WALS and that of the land owner.

4.3 Stream Environmental Rating

The overall stream environment is currently rated ‘Moderate’ (WRC, 1999) with an environmental

rating of 21. The area has:

Good vegetation cover, but this cover is composed of both native and exotic flora

Localised clearing however disturbance is not recent

Abundant shade and overhanging vegetation

Some emergent aquatic vegetation within the stream

Localised erosion, bank collapse and sediment heaping

A stream environment with at least two habitat types including riffles and pools

Since the Annual Stream Bank Assessment (ASBA) provided to WALS in November 2006, the

condition of floodway and bank vegetation has remained unchanged (‘Moderate’) as the area has

localised clearing, however disturbance is not recent and has good vegetation cover, consisting of a

mixture of native and exotic flora. The condition of verge vegetation has shown slight improvement,

with mostly ‘Moderate’ conditions noted as opposed to the ‘Moderate’ to ‘Poor’ found in the ASBA

provided in November 2006. Stream cover remains unchanged (‘Good’) since 2007 with abundant

shade and overhanging vegetation and some emergent aquatic vegetation present. In the ASBA

provided in November 2006 steam cover was rated ‘Good’ to ‘Moderate’ showing that revegetation

undertaken by GHEMS in 2006, natural recruitment, fencing and weed control has improved the

stream’s condition. Bank stability has reduced from ‘good’ to ‘moderate’ with increased erosion of the

stream bank between ponds 1 & 2. If action is not taken to mitigate erosion and ensure bank

stability WALS may be in danger of losing its ‘moderate’ environmental standing. The stream is

currently supporting at least two aquatic habitats including riffles and pools.



5. CURRENT IMPACTS DUE TO LANDFILL OPERATION

Current impacts are minimal with full water flow returned to the creek. Likely impacts include a build-

up of debris as a direct result of WALS activities.

6. IMPACTS DUE TO CURRENT LAND MANAGEMENT PRACTICES IN

ADJACENT FARMLAND

Fences have been repaired since last year’s reporting, thus restricting access for livestock to the

WALS site, however some sections of the fence do require maintenance and if left unchecked,

livestock could return.

The presence of Gomphocarpus fruticosus (Cotton Bush) in the adjacent property is likely to be

impacting on the vegetation quality within the stream environment, as Cotton Bush seedlings

appearing in the survey area likely originate from from parent plants on the adjacent property.

7. WATER QUALITY MONITORING

Due to the proximity of landfill operations, the water quality of the creek, including both surface water

and groundwater, is monitored to detect any changes in chemical and particulate composition. This

ensures that any impacts resulting from landfill activities are identified and can be managed to keep

water quality indicators within acceptable limits.

Monitoring of the quality of water discharging from the storage dam into the diversion stream west of

the bottom storage dam, which flows into Cardup Brook is conducted monthly by Western Australian

Landfill Service (WALS).

Data has been supplied by WALS for the period 7 January 2011 to 2 December 2011 recording the

following parameters: acidity (pH), total dissolved solids (TDS), and total suspended solids (TSS),

Ammonium and conductivity.

This data is shown in Table 1.

Monthly water quality and rainfall averages for this period are summarised in Appendix 4.



Table 1: Water Quality Monitoring Data Summary for 2011 (WALS, 2011) 7.1 pH Levels

The National Health and Medical Research Council (NHMRC) stipulates the acceptable pH range for

drinking water as being between 6.5 and 8.5 (NHMRC, 2009). Results for the assessment period of

2011 indicate that, while pH levels for surface water are neutral and fall within an acceptable range,

the underdrainage areas regularly fall outside these ranges. Of particular note is the discharge

emanating from UD5 and UD3, both of which consistently exceeded the lower pH limit. Water

discharge which exceeds the NHMRC guidelines could potentially negatively impact the water quality

in Cardup Brook.

The Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC &

ARMCANZ, 2000) defines trigger values for physical and chemical parameters. These values are

used to assess the point at which adverse impacts on stream environments are likely to occur.

ANZECC and ARMCANZ (2000) define upper and lower limit trigger values for pH in lowland rivers

as being between 6.5 and 8.0. As in previous years readings for underdrainage and surface water

discharge from the South Cardup site generally exceed trigger values with SW4 the only one to fall

within acceptable limits. Management and continued monitoring is recommended, especially since

SW1, UD5 & UD3 are close to acceptable pH levels.

Parameter Discharge (SW4) Retention (SW1)

Range Median Average Range Median Average

pH 6.6-8.0

7.8

7.7 7.3-8.5 8.2 8.1

TDS (mg/L) 350-1300 573 668.55 306-1400 653.7 894.35

TSS (mg/L) <5-810 37 104.8 <5-1000 134.5

Ammonia 1.800-0.071

0.205 0.322 <0.005-

0.64 1.002

0.129

Conductivity @25 C

8-1900 880 996.1 530-1900 1150 1283.666

Parameter UD5 UD3

Range Median Average Range Median Average

pH 6-6.5

6.2

6.2

5.9-6.4 6.3 6.3

TDS (mg/L) 1070-1160

1003.15 1114 282-964 825 724

TSS (mg/L) <5 <5 <5 7-25 15.5 17.88

Ammonia

<0.005-0.14

0.018 0.0483 0.51-2.1

0.975

0.9878

Conductivity @25 C

1900-2000 2000 1961 520-1400 1400 1175.556



7.2 Total Dissolved Solids (TDS) Total Dissolved Solids (TDS) are a measure of inorganic salts dissolved in solution (water) and can

be used as a measure of salinity. The concentration of TDS in natural waters can range widely from

<1mg/L in rainwater to 3500mg/L in seawater. The range of TDS is dependent on addition of salts

from natural weathering processes or through human activities. Total Dissolved Solids can range

from <495mg/L (fresh) to 550-1500mg/L (marginal). Rainfall is highly influential on levels of TDS and

low summer rains combined with high evaporation increases the level of TDS in solution.

On average Perth receives 854 mm of rainfall per annum. In 2011, Perth received 860.8mm of rain

slightly above average. However during 2010 only 503.8 mm of rain was recorded.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

2012 5.6 5.6

2011 30.2 0.4 0 19.4 85 171.4 161 115.2 109.2 64.2 29 75.8 860.8

Average 9.6 12.7 19.5 44.1 117.5 175.7 169.7 133.6 80.6 52.2 22.1 12.8 850

Figure 1: Cumulative Rainfall for Perth (2009-2012) and monthly rainfall data for 2011 (Water

Corporation, 2012)

Average levels of TDS for the 2010 reporting period range between 668.85mg/L – 1114.00mg/L.

Average TDS levels for SW1, SW4 and UD3 are less than that of the 2010 reporting period; however

UD5 has increased from 977.56mg/L in 2010 to 1114.00mg/L in 2011. Typically UD5 has always



recorded higher averages across all reporting periods. Ranges have also decreased compared with

that of the 2010 reporting period, and are more consistent with that of the 2008 & 2009 reporting

periods. However water monitoring periods (Appendix 4) indicate that there are quite sudden spikes

in TDS levels and this should be monitored closely. The reduction in overall TDS levels is likely due

to the higher rainfall experienced during with 2011 compared with that of 2010. As the the Cardup

land fill goes into remission and site activity decreases there should be a further reduction in TDS

levels. .

ANZECC & ARMCANZ (2000) measure upper and lower trigger values for TDS in millisemens

(uScm-1) and all ASBA reports measure TDS in mg/L. With no conversion possible between these

measurements it is not possible to calculate whether measurements for TDS in the current ABSA

report are within the trigger values recommended in ANZECC & ARMCANZ (2000). It is

recommended that in future WALS record all TDS measurements in uScm-1 so as comparison can

be made to ANZECC & ARMCANZ allowing my concise conclusions to be drawn.

7.3 Total Suspended Solids (TSS) There is no guideline based on health considerations for turbidity (TSS) due to a lack of data

(NHMRC, 2004). The NHMRC (2004) have however stated that for aesthetic reasons TSS should

not exceed 5 NTU (Nephelometric Turbidity Units), and that unfiltered Australian drinking water

turbidity readings typically range from 1NTU to 65NTU. The Australian and New Zealand Guidelines

for Fresh and Marine Water Quality (ANZECC & ARMCANZ, 2000) has set a default trigger value

range of 10 NTU to 20 NTU for lowland rivers in slightly disturbed ecosystems in south-west

Australia. This guideline is highly subjective to site specific variability but is aimed at protecting a

range of aquatic ecosystems.

In Western Australia, TSS is still measured in mg/L. As there is currently no equivalent guideline for

TSS and there is no one method of conversion between mg/L and NTU, it is difficult to compare the

results of this assessment to the National guidelines for turbidity.

The State-wide River Water Quality Assessment undertaken by the Western Australian Department

of Water in 2004 (Department of Water, 2008) sets out the following guidelines for the median TSS

recording:

Low: 0 – 5mg/L

Moderate: 6 – 10mg/L

High: 11 – 25mg/L

Very High: >25mg/L

During the reporting period of 2011, average surface water TSS were 104.8 & 134.5 mg/L for SW4

and SW1 respectively, and <5 & 17.88 mg/L for UD5 and UD3. Both SW4 and SW1 have increased

substantially from the previous reporting period (54.4 & 48.86 mg/L), while UD5 & UD3 have

decreased (12.5 & 29 mg/L).

The range of TSS levels varies drastically during each sampling period and are not necessarily

consistently high, Table 1. However total rainfall was significantly higher in 2011, 860.8mm



compared with that of 2010, 503.8mm. Given that TSS levels typically increase during peak rainfall

months (Appendix 4) it is expected that the average TSS mg/L levels would increase given the

higher rainfall experienced during 2011. During all sampling periods UD5 consistently recorded TSS

levels less than 5mg/L, however sampling could only be conducted on six occasions (Appendix 4).

Site disturbance has not been as high in previous years and it is encouraging to see a reduction in

TSS mg/L levels from 2010 for both UD5 12.5mg/L & UD3 29 mg/L given the higher rainfall. This

places the underdrainage areas in the low and high categories set by the Department of Water,

2004.

Although the TSS levels are lower than those recorded in previous years, TSS levels are still very

high in many of the samples, especially the surface water readings.

The effect of the retention and sediment dams on water quality is positive and levels of TSS entering

Cardup Brook are likely to be higher in the absence of these structures.

It is recommended that in future WALS record all TSS measurements in NTU so as comparison can

be made to ANZECC & ARMCANZ (2000).

7.4 Ammonium and Conductivity

Ammonium and conductivity levels are below threshold levels at which point adverse impacts on

stream environments are likely (ANZECC & ARMCANZ, 2000). ANZECC define the trigger value for

ammonium in lowland rivers as being 80 µg N L-1 and define trigger values for conductivity in these

rivers as being between

300-1500 µScm-1 (Table 1). No averages exceed the trigger value for ammonium, however UD5 is

the only site to exceed trigger values for conductivity with an average of 1961 µScm-1 this is an

increase from the 2010 reporting period. This is concerning given that all other sites recorded

reduced averages compared with that of 2010. Although there are reductions, spikes in conductivity

do occur over the course of the monitoring program and this requires further monitoring especially

since conductivity µScm-1 for UD5 has increased and sits above recommended trigger values.

7.5 Leachate spill

During 2010, a leachate spill occurred which resulted in approximately 100 KL being released into

the Cardup creek system. Monitoring of the surface and groundwater was conducted for each

chemical identified as a possible source of concern; nitrogen, metals, hydrocarbons and dieldrin. It is

evident during the 2011 monitoring period that there are no lasting environmental impacts from the

leachate spill and that all remediation efforts have so far worked.



8. ACTIONS TAKEN IN RESPONSE TO PREVIOUS RECOMMENDATIONS

As in previous years GHEMS Holdings Pty Ltd have made recommendations to WALS regarding weed management, livestock management and revegetation works to improve the quality of the steam and riparian zone. WALS has taken measures to fulfil these recommendations by implementing the following actions.

Water has been returned to the stream and this is critical in helping to stabilise the

stream bank as well helping to reduce erosion. It also enables the continued survival

and regeneration of fringing vegetation.

The boundary fence has been repaired and has halted livestock from entering the

WALS site, however regular upkeep and maintenance is required to ensure livestock

do not gain access in the future.

9. RECOMMENDATIONS FROM CURRENT ASSESSMENT

The following actions are recommended to increase water quality and the condition of vegetation in

and around the stream draining from the WALS site into Cardup Brook

Recommendations:

Continued maintenance and repairs of boundary fencing. If left unchecked livestock may

return and could easily undermine the progress made in previous years in regard to

vegetation cover and natural regeneration. It is also critical livestock do not return to the area

given the fragile state of the steam bank.

Remove debris and rubbish from stream and ponds on the WALS site to reduce water build

ups and overflow, leading to further erosion damage.

Although not the responsibility of WALS, contact should be made with the adjacent land

owner who shares Cardup creek, in regard to removal of declared weeds, debris in creek as

well as restricting livestock access to the creek.

Further revegetation should be undertaken along the steam bank east of the access road to

minimise further erosion and undercutting damage. Revegetation should focus on increasing

the percentage of Baumea articulata as this acts to stabilise the stream banks, reduces water

flow, assists in sediment deposition, nutrient and pollutant stripping.

Previous recommendations:

Hydrologists evaluate the bottom storage dam with the aim of increasing the dam’s size so it

has the capacity to hold and slow a large volume of water. This action will give greater time

for sedimentation thus reducing TSS and as the dam dries through summer sediment can be

removed thus also removing any salt crust and potentially reducing TSS when the dam fills in

winter.

Weed control be expanded to target not just Declared Weed Species (DAFWA 2008) but to

target all weed species on the site. Weed control combined with small scale revegetation

works will see considerable increases in the ecological services this stream provides and a

reduction in the impact the WALS South Cardup site has on water quality downstream.

Weed control will also see the Stream Environmental Rating increase (WRC, 1999).



Readings for Total Suspended Solids (TSS) be taken in both mg/L and NTU (Nephelometric

Turbidity Units) so accurate comparisons with National Guidelines and ANZECC &

ARMCANZ (2000) can be made.

Readings for Ammonium and TDS/conductivity be recorded in N L-1 and uScm-1, respectively

so as comparison can be made with guidelines prescribed in ANZECC & ARMCANZ (2000).

Actions to continue:

Maintenance of weed control for Declared Weed Species (DAFWA 2009).

Maintenance of fencing to exclude livestock.

Maintenance of mobile rubbish collection.

Maintenance of regular water quality monitoring including assessment of Total Dissolved

Solids (TSS) discharging into the stream from the storage dam.

10. Conclusions

This assessment has rated the foreshore condition of WALS site as B3 ‘degraded’- understory weed

dominated, with natives occupying most of the canopy. Regeneration is occurring and this is crucial

in reducing the percentage of weeds while increasing the foreshore condition rating of the WALS

site. Revegetation works undertaken by GHEMS Holdings Pty Ltd has continued to improve the

condition of the area west of the access road, however erosion and undercutting is present along

some sections of the stream bank and appears to have become worse than in previous years, thus

revegetation focusing on Baumea articulata should be undertaken to stabilise the stream bank

(section 8).

Unfortunately the adjacent land is rated as C1 ‘Eroding or Erosion Prone’. Although not the

responsibility of WALS, overall improvement of foreshore condition on the WALS site cannot happen

without mitigation of environmental factors on both sides.

The overall Stream Environmental Rating remains at ‘Moderate’ (WRC 1 ). On the whole the site

appears to be improving, however points were lost given the erosion and undercutting that is

prevalent around the stream bank west of the access road. The rating can be improved by mitigating

erosion and undercutting problem. Continued weed control and increasing fringing vegetation will

also help improve the environmental rating. If efforts are not made to remediate both erosion and

weed problems, the overall environmental rating may be downgraded to poor during the following

reporting period.

Several weed species were recorded during the current survey (section 4.1), with two of these

species (Cotton Bush and Patterson’s Curse) being noted as declared weed species (DAFWA,

2008). Weed invasion, most importantly by Cotton Bush, has potential to further impact on the

stream. Although WALS is attempting to manage this issue, the infestations on the adjacent property

will continue to affect the weed management within the landfill lease and should be addressed by the

landholder. Several species such as ruby dock (Rumex vesicarius) that were not present during the

2010 reporting period were identified during this reporting period and although only several plants

were recorded, it highlights the importance of maintaining a more thorough weed control program

and the difficulties associated with high weed infestations on adjacent properties.



The fence has been maintained and appears successful in restricting livestock access to date.

However some sections of the fence appear to be in need of further maintenance leaving the

opportunity for livestock to gain access in the future if repairs are not undertaken.

The issue of mobile rubbish will continue for the life of the facility, with the potential for pollution

further downstream potentially blocking culverts and interfering with stream flow. Staff at WALS have

been taking measures to reduce mobile rubbish on site and on the adjacent property through regular

rubbish collection and removal. This has been on the most part successful and it is critical to

maintain a regular rubbish removal program.

Erosion in some sections of the stream, particularly between ponds 1 & 2 has increased slightly and

this could become a concern in the future. The creek was dry for a period during 2010 when WALS

water requirements increased, but this in turn destabilised the steam bank. Given the higher rainfall

in 2011 compared with 2010, much of the surface sediment has potentially been removed. Rubbish

and debris build up in the stream can cause some sections to become dammed, thus increasing

water velocity with overflow occurrences, which in turn remove surface sediment and de-stabilise the

stream bank.

Nonetheless, current management practices have stabilised the stream banks and improved the

quality of waters in the stream over the recording period. Recommendations outlined in section 10

should be implemented to further increase the stream’s health reduce TSS/TDS and to keep water

parameters such as pH, Ammonium and conductivity within limits that will not adversely affect the

streams biota.



11. STREAM BANK ASSESSMENT PHOTOS

Photo 1: Rubbish in the top storage dam eventually makes its way down the creek and can block

culverts. If left unchecked it can contribute to damming of smaller sections of the creek.

Photo 2: Erosion of stream bank between ponds 1 and 2 west of the access road. This section

continues for several meters.



Photo 3: Erosion and undercutting of surface sediments around the bottom storage dam. If left

unchecked this could further increase.

Photo 4: Fallen trees across the creek enable debris and rubbish to build up, damming water and

leading to overflows of high velocity water which in turn can lead to erosion of surface sediments and

thus de-stabilisation of the stream bank.



Photo 5: Although much of the boundary fence has been repaired, fallen branches have damaged

some sections of the fence. If left unchecked, livestock could return to the area.

Photo 6: Eucalypt sapling located around bottom storage dam. Numerous saplings were noted

during this assessment and this provides encouraging sings for the area.



12. References ANZECC & ARMCANZ. (2000). National Water Quality Management Strategy: An Introduction to

Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Canberra,

ANZECC. Retrieved 12 November 2009 from:

http://www.mincos.gov.au/publications/australian_and_new_zealand_guidelines_

for_freh_and_marine_water_quality

DAFWA. (2008). Declared plants list, Agriculture and Related Resources Act, 1976. Agriculture

Protection Board: South Perth, WA. Retrieved 12 November 2009 from:

http://www.agric.wa.gov.au/PC_93088.html?s=1001,Topic=PC_93079

Department of Water, Western Australia. (2008). Statewide river water quality

Assessment. Retrieved 25 February 2008 from:

http://apostle.environment.wa.gov.au/idelve/srwqa/metadata_statements/srwqa.html

Keighery, B.J. (1994). Bushland Plant Survey: A Guide to Plant Community Survey for the

Community. Wildflower Society of WA (Inc.) Nedlands, Western Australia.

National Health and Medical Research Council. (2004). National water quality

management strategy: Australian Drinking Water Guidelines 6. Retrieved 12 November 2009

from:

http://www.nhmrc.gov.au/_files_nhmrc/file/publications/synopses/adwg_11_06.pdf

URS. (2000). Annual assessment of stormwater discharge from the southern

landfill, South Cardup, to the Serpentine River.

Water Corporation. (2009). Rainfall in Western Australia: Rainfall in Perth (cumulative). Retrieved 8

January 2012 from:

http://www.watercorporation.com.au/R/rainfall.cfm

West Australian Landfill Services (2008). Annual water sampling results for retention, sediment and

bottom storage dams. (pers com Ron Boucher, February 2008)

WRC. (1999). Planning and Management: Foreshore condition assessment in

farming areas of south-west Western Australia. Water and Rivers Commission River

Restoration Report No. RR3

http://www.mincos.gov.au/publications/australian_and_new_zealand_guidelines_

http://www.agric.wa.gov.au/PC_93088.html?s=1001,Topic=PC_93079

http://apostle.environment.wa.gov.au/idelve/srwqa/metadata_statements/srwqa.html



APPENDIX 1:

SOUTH CARDUP LANDFILL SITE



APPENDIX 2:

FORESHORE CONDITION ASSESSMENT REPORT (WRC, 1999)



APPENDIX 3:

ELEMENT OF FORESHORE CONDITION ASSESSMENT SYSTEM (WRC, 1999)



3. Elements of the foreshore condition assessment system

The foreshore condition assessment has been developed

from observations of river system degradation

throughout south-west Australia. The system follows the

general process of remnant bush degradation, with the

added complication of erosion as stream banks become

exposed.

The system has been designed to allow for a varied level

of assessment. It consists of a number of stages or

grades, A, B, C and D, beginning at pristine and running

through to completely degraded. To perform more

detailed surveys each grade has three sub-levels that are

easy to recognise (section 3.2).

3.1 Foreshore condition - basic

assessment

The basic survey is used when assessing long river

sections or for a basic survey at paddock level. In the

basic survey, you grade the foreshore into one of four

categories, A, B, C and D. Just tick the appropriate box

on the survey form. These grades are simple to

recognise and are illustrated in Figure 2 and on the

paddock scale survey form (section 4).

A grade is where the foreshore has healthy native bush,

similar to that which you would see in most

nature reserves, state forests and national parks.

B grade is where the bush along the stream has been

invaded by weeds, mainly grasses, and looks

like typical roadside bush. For example, in

winter, soft light green leaved grasses are

usually seen, along with flatweeds and maybe

more substantial weeds such as Watsonia and

bridal creeper. In summer or autumn, dry,

yellowing dead grasses or their remnant seed

heads are seen amongst the bush.

C grade is where the foreshore supports only trees over

weeds or pasture, or just plain pasture, and

bank erosion and subsidence may be occurring,

but only in a few spots.

D grade is where the stream is little more than an

eroding ditch or a weed infested drain. Here,

think of the typical drains you have seen, either

just after having been cleaned out with a

backhoe or in need of a clean out.

If the condition of the foreshore varies, tick the box on

the survey form that you think best represents the

general overall condition.

3.2 Detailed assessment of foreshor e

condition

If you are interested, and have the confidence, you

can assess foreshore in more detail. Each grade has

three sub-categories. They are reasonably simple to

recognise.

A1. Pristine

The river embankments and floodway are entirely

vegetated with native species, and there is no evidence

of human presence or livestock damage.

A2. Near pristine

Native vegetation dominates. Some introduced weeds

may be present in the understorey, but not to the extent

that they displace native species. Otherwise there is no

evidence of human impact. (A river valley in this

condition is as good as will be found today)

A3. Slightly disturbed

Native vegetation dominates, but there are some areas of

human disturbance where soil may be exposed and

weeds are relatively dense (such as along tracks). The

native vegetation would quickly recolonise the disturbed

areas if human activity declined.

B1. Degraded - weed infested

Weeds have become a significant component of the

understorey vegetation. Although native species are

dominant, a few have been replaced by weeds.



B2. Degraded - heavily weed infested

In the understorey, weeds are about as abundant as

native species. The regeneration of some tree and large

shrub species may have declined.

B3. Degraded - weed dominated

Weeds dominate the understorey, but many native

species remain. Some trees and large shrub species may

have declined or disappeared altogether.

C1. Erosion prone

Trees remain, and possibly some large shrubs or tree

grasses, but the understorey consists entirely of weeds,

mainly annual grasses. The trees are generally resilient

or long lived species but there is little or no evidence of

regeneration. The shallow-rooted weedy understorey

provides no support to the soil, and only a small increase

in physical disturbance will expose the soil and make the

river embankments and floodway vulnerable to erosion.

C2. Soil exposed

Older trees remain, but the ground is virtually bare.

Annual grasses and other weeds have been removed by

livestock trampling or grazing, or through over use by

humans. Low-level soil erosion has begun, by the action

of either wind or water.

C3. Eroded

Soil is washed away from between tree roots, trees are

being undermined and unsupported embankments are

subsiding into the river valley.

D1. Ditch - eroding

There is not enough fringing vegetation to control

erosion Some trees and shrubs remain and act to retard

erosion in certain spots, but are doomed to be

undermined eventually.

D2. Ditch - freely eroding

No significant fringing vegetation remains and erosion is

completely out of control. Undermined and subsided

embankments are common, and large sediment plumes

are visible along the river channel.

D3. Drain - weed dominated

The highly eroded river valley has been fenced off,

preventing control of weeds by stock. Perennial (long-

lived) weeds have become established. The river has

become a simple drain, similar or identical to a typical

major urban drain.

Sometimes when assessing the condition of a foreshore

you may think it is too variable to tick any one box and

you may wish to express the full range of condition.

This can be done. For example, you may think that the

condition ranges between A3 and B2. If so, simply tick

both boxes. On the other hand, you may think that while

it is mainly B1, it ranges between A3 and B2. In this

case tick A3 and B2, and tick B1 twice. Similarly, if you

think it ranges between A3 and B2, but is mostly B2, tick

A3 once and B2 twice.

The survey forms are also designed to allow for the

collection of other information relating to soils, bank

stability and environmental health that you may find

useful when planning management works. The

collection of this information is optional and is discussed

further is Section 4.

3.3 Fencing status

This will provide information on whether the stream is

fenced off or not and whether stock have access to the

land.

Fenced off - tick yes only if the the fence is in good

order and is actually functioning as a fence.

Stock access - tick yes if it appears that stock have had

access to the river/creek recently, even if the streamline

is fenced off.

Crossing point - tick yes if there is a livestock or vehicle

crossing point across the stream.

3.4 Additional information

As well as general stream condition there are other

factors that you can assess which will provide valuable

information to assist with planning your management

options. These factors will help you to prioritise works

and to identify areas that may be prone to degradation.

3.4.1 Bank steepness

Steep banks are more prone to erosion and collapse than

more moderately sloped ones. Combined with soil

cohesion information, this will highlight points of high

erosion hazards. Tick the box which best represents the

foreshore being surveyed.



3.4.2 General Soil Cohesion

The degree of cohesiveness of the stream embankment

determines how vulnerable it is to erosion and

subsidence once the supporting vegetation has been lost.

Rocky embankments are extremely cohesive and the

erosion of surface sediment is limited. Clayey soils are

reasonably cohesive and only erode slowly, although

loose surface sediment is quickly lost. Non-cohesive

embankments of sand, loam or dispersive clays are the

most prone to erosion and collapse. Tick the box which

best represents the foreshore being surveyed.

3.4.3 Major Erosion/siltation

Any point of erosion that produces more than a trailer

load worth of sediment can be considered ‘major’.

Erosion types include simple cutting into the stream

bank, undercutting of stream banks, firebreak or track

washouts, and subsidence. Also indicate if there are

large heaps of sediment, usually seen as white sand. Use

the comments to give additional information such as the

extent of the erosion or whether sediment is filling a

river pool. This information will be used to identify

“black spot” areas. Tick the appropriate boxes.

3.4.4 Vegetation health

Use this section to give a general description of the

health and vigour of the vegetation. This information is

needed to identify sections of foreshore that may

become unsupported by trees in the near future. Be sure

to note the presence or absence of regenerating trees.

The mature trees may be dead or sick looking, but if

young ones are present, they may replace the old ones.

Alternatively, adult trees may be healthy but no

regeneration is occurring. Tick the appropriate boxes.

3.5 Stream health assessment - living

streams survey

The living streams survey provides an indication of

stream health based on an assessment of the quality and

diversity of habitats. The following factors are used as

assessment parameters to help identify the health of the

habitat around the stream you are monitoring (see

sections below for an explanation of these):

• Floodway bank and vegetation

• Verge vegetation

• Stream cover

• Bank stability and erosion

• Habitat diversity

• Surrounding land use

Plants provide habitat for birds, frogs, possums, and

many other organisms which live in and around streams.

The completeness of this zone is important for the

existence and health of all types of creatures ranging

from mosquito larvae through to large birds and

mammals. Leaf litter from overhanging trees, and fallen

branches provide a food and shelter for fish, crayfish and

other aquatic life. Shade provided by overhanging

vegetation influences stream temperatures and light.

Rivers and streams which are dominate by introduced

plants (exotics), such as willow trees, cannot supply a

year round shelter and food supply which is so important

for our aquatic life.

Each of the assessment parameters is ranked from

excellent through to very poor. A numerical score has

also been given to each ranking and the score system

has been calculated to give more weighting to conditions

which are more important to stream health, such as

shade and the presence of areas of permanent water,

which are very important to aquatic life in a region

characterised by long hot dry summers. Add up the total

value of all the boxes you have ticked on your record

sheet under stream environmental health rating. This

will give you a total score, which you can evaluate

against the table below to give you an overall rating of

stream health.

Score Rating

40-55 Excellent

30-39 Good

20-29 Moderate

10-19 Poor

0-9 Very poor



3.5.1 Floodway and bank vegetation

This vegetation grows in the floodway (Fig. 1) or on the

banks and is the major natural source of nutrients and

carbon for the stream ecosystem. The canopy is the tree

cover that overhangs the stream. Plant roots stabilise the

floodway and banks against erosion and subsidence.

Stems and foliage dissipate the energy of floodwaters,

reducing erosion and promoting sedimentation.

3.5.2 Verge vegetation

The stream verge extends from the top of the

embankment to a paddock fence, backyard fence or road,

and is usually about 10-50 m wide. Sometimes the verge

is part of streamside parkland. Verge vegetation provides

habitat next to water, increases the value of the riparian

zone as an ecological corridor and stabilises the stream

banks by anchoring them with tree roots to adjacent land.

3.5.3 Stream cover

Fish and other aquatic organisms require snags, leaf

litter and rocks to shelter from predators and fast flowing

water, to reproduce, establish territories, and for

navigation. Aquatic plants are also very important for

fish and other creatures in the stream. They have a direct

effect on the available oxygen in the water, which in turn

can affect the type of fish and other animals found.

Protruding snags and rocks provide roosting and

preening sites for birds and help to oxygenate water in

fast flowing sections. Overhanging and emergent

vegetation provides shade to which many aquatic

animals retreat during the hot days of summer and

autumn. Insects blown from flowers and leaves are a

very important source of food for fish and other animals.

3.5.4 Bank stability and erosion

Banks sometimes naturally erode on bends (meanders).

However, when vegetation is cleared for agricultural

activities and urban development, the stream banks can

become unstable, resulting in extensive erosion along

the floodway and the build-up of sediment that is then

slowly washed downstream. Erosion and bank collapse

can also be caused by increased runoff from impervious

surfaces (e.g. car parks), from pipes and drains, and by

straightening or channelling the stream.

3.5.5 Habitat diversity: cascades, runs

riffles, pools and meanders.

Different habitat types in streams include cascades,

rapids, riffles, waterfalls (which are quite rare), runs,

meanders, pools and floodplains. Stream sections that

have a range of habitat types can support a greater

variety of species.

Rapids occur where rocks and snags protrude through

rapidly flowing water. Areas where water flows quickly

over stones and rocks, or between tree stems, are known

as riffles. Areas where the water surface is essentially

flat, are known as runs. Rapids and riffles aerate water

and provide habitat for invertebrates. It is common for

the stream floodway, including rapids and riffles, to be

heavily vegetated.

The vegetated floodways are usually broken by deep

pools which provide habitat for fish, turtles, marron and

other animals. Pools are often the only parts of streams

to retain water over summer, providing an essential

drought refuge.

Long broad sections of vegetated or clear floodway are

typical of the lower reaches of our larger south-west

rivers. They provide different types of habitats because

the cutting action of water at bends creates deeper areas

and variable water speed. Seasonal floodwaters adjacent

to the stream may provide important breeding and

feeding habitat for aquatic life.

3.5.6 Surrounding land use

The surrounding land use activities will contribute

greatly to the ecological value of the stream. An area of

national park or remnant bush contribute to, and benefit

from, a wider biological diversity than can be found in

either the stream or bushland alone. A stream in an

agricultural setting will have elevated sediment and

nutrient levels, while a stream in an urban or industrial

area will be more vulnerable to weed invasion and

pollution. Native animals living in urban and semi-rural

areas benefit from a stream environment or from the

remnant bush along its flanks.



APPENDIX 4:

WATER QUALITY DATA

appendix e - · pdf fileannual stream bank assessment . ... stream cover, bank stability and...

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