port of dover tidal energy...the dover site provides a suitable location for the evaluation of tidal...

Port of Dover

Tidal Energy

Proposals, considerations and scope of further work

Contents

1.0. INTRODUCTION ................................................................................................................ 3

1.1. Port of Dover ................................................................................................................. 3

1.2. Project Description ......................................................................................................... 3

OVERVIEW OF THE EXISTING ENVIRONMENT ................................................................................ 7

2.0. HYDRODYNAMICS & SEDIMENTARY REGIME ....................................................................... 7

2.1. Potential Issues .............................................................................................................. 8

2.2. Further Assessment ........................................................................................................ 8

3.0. BENTHIC ECOLOGY ............................................................................................................ 9

3.1. Potential Issues arising during the Installation Phase ...................................................... 10

3.2. Potential Issues arising from the Operational Phase ........................................................ 11

3.3. Further Assessment ...................................................................................................... 11

4.0. FISH & SHELLFISH ........................................................................................................... 12

4.1. Potential Issues arising from the Installation Phase ........................................................ 13



5.0. MARINE MAMMALS .......................................................................................................... 15


5.2. Potential issues arising from the Operational Phase ........................................................ 17


6.0. ORNITHOLOGY ................................................................................................................ 18




7.0. NAVIGATION ................................................................................................................... 19

7.1. Potential Issues ............................................................................................................ 20


8.0. DESIGNATED SITES ......................................................................................................... 20

1.0. INTRODUCTION

This document outlines the proposals and current considerations for the development of tidal energy

at the Port of Dover. Dover Harbour Board (DHB), the Harbour authority for the port, is proposing to

take through to feasibility a small tidal array of up to 0.99MW capacity within the Port jurisdiction.

DHB has been approved matched North-West Europe (NWE) INTERREG funding for the proposed

project. This will involve research and modelling of devices, leading onto a pilot. Providing the results

from testing are environmentally and economically viable the project will lead onto the small scale

array.

This document is prepared as a consultation document of the proposed project to aid project planning

and design during feasibility. DHB has anticipated that the project will not exceed limits or thresholds

to which a formal Environmental Impact Assessment (EIA) will be required under the Marine Works

(Environmental Impact Assessment) Regulations 2007. Annex II, projects subject to Article 4, 3.

Energy Industry (j) Instillations for hydroelectric energy production. However an environmental

appraisal taking into account aspects to minimise potential affects will be completed to form part of

the licence application.

1.1. Port of Dover

The Port of Dover is one of the worlds busiest international ferry ports, additionally providing berths

for Cruise Liners, cargo ships, aggregates and pleasure craft. It is a significant asset for Dover, East

Kent, the South East and the nation. As a transport node it has enormous national and international

importance as one of the UK’s main trade gateways with continental Europe.

Dover Harbour Board (DHB) is the harbour authority for the port and it is committed to delivering a

sustainable port operation that will minimise its environmental impacts. With this outlook the port

community works hard to reduce the carbon footprint of its operations and has been actively working

towards reducing it since 2006. Registered to both the Carbon Trust Standard and Carbon Reduction

Commitment Energy Efficiency Scheme DHB has been making year on year reductions in its biggest

emissions source, purchased electricity. The requirements of these schemes demonstrate that DHB is

actively engaged in tackling its carbon footprint as a business necessity.

Recognising future resource concerns DHB appreciates the importance of marine renewables as part

of the future energy mix, and believes it has the capability to take a tidal energy project forward. The

proposed project provides the opportunity to test smaller devices in a commercial location and it is

anticipated that Dover could become a showcase for small scale tidal energy generation,

demonstrating a commercially viable energy production utility operating adjacent to one of the

busiest ports in Europe.

1.2. Project Description

The Dover site provides a suitable location for the evaluation of tidal energy in the narrow Dover

straits area of the channel. It is within 500metres of HV connectivity and the Port has a high local

energy demand of around 2Mw. In addition to these aspects there is ample local engineering and

marine expertise, much of it directly employed by Dover Harbour Board.

Figure 1. Tidal Energy Investigation Zone. A broad scale view was taken and the most suitable area for tidal energy extraction within the port jurisdiction was located outside the Harbour to the south of the Southern Breakwater. The tidal flow in this location is estimated to peak between 4 and 5 knots identified from past surveys, and detailed in the Port of Dover Tidal Atlas.

The proposed location identified in figure 1 takes into consideration:

The most beneficial tidal flow with current knowledge

Broad scale view of environmental requirements and designations

Navigational requirements

Figure 2. The location plan for a possible final array (device dependant) in the investigation zone gives a sense of the small scale of the project; this drawing represents around 10 devices, each with an expected 6m blade.

Tidal Energy Power Station Programme

2013 Feasibility Phase

- Environmental surveys and studies

- Infrastructure Identification

- Testing and technology selection

- Consents licences and approvals

2013-14 Design Phase (including testing and studies)

- Environmental assessments

- Tidal performance testing

- Technology selection

- Infrastructure specification

2014-15 Implementation and Evaluation Phase (Pilot system instillation)

A number of devices are considered at this current stage including seabed tethered devices seabed

structures and those supported buoyantly on piles/structures. An initial desktop feasibility exercise

comprising of flow modelling, environmental impact assessment, navigational safety assessment and

life costs will determine what devices can be taken forward to pilot deployment. The pilot study may

involve short term deployment of selected device/devices. This pilot will enable further assessment of

the device/devices performance and compatibility to the site. The pilot study is expected to inform

future maintenance requirements as well as an understanding of the applicability of port

infrastructure to energy generation. In summary, a pilot will provide key evidence that will be

required for the development of a power station anticipated at the later stages of the project.

OVERVIEW OF THE EXISTING ENVIRONMENT

This section gives an overview of the Port and adjacent environment, to aid in identifying the

potential issues on which further assessment should focus and the scope of work required to

investigate these issues. DHB has an established environmental monitoring programme which has

been carried out since 1992. The programme of historical and up-to-date data includes; pelagic and

benthic species, algae, water quality, ornithology, crustaceans, littoral and terrestrial ecology. This

database allows monitoring of spatial and temporal trends within and adjacent to the harbour across

the range of natural and artificially created habitats. The environmental data is retained in the Port of

Dover Environmental Database.

Baseline environmental data has been generated from the Port of Dover Environmental Database,

surveys carried out as part of the Terminal 2 Environmental Impact Assessment (EIA) as well as other

relevant databases and literature.

The subsequent sub-sections will:

Establish known baseline conditions

Identify potential impacts associated with the proposed project

Identify further assessment work

2.0. HYDRODYNAMICS & SEDIMENTARY REGIME

The harbour is an artificial structure which protrudes out from the surrounding coastline deflecting

and accelerating the flows of water around its structures, creating a dynamic and complex

hydrodynamic system. The predominant south south-westerly wave conditions are refracted around

the Admiralty Pier and through the Western Entrance, with reduced wave conditions toward the

Eastern Entrance. Flow models of the Port and its jurisdiction exist in the Port of Dover Tidal Atlas

2002, the flow patterns show that the course of the water in the channel runs from Northeast to

Southwest during low water, and during high water the flow is reversed. The harbour structures,

particularly the presence of the harbour entrances, create jet streams and these can produce

turbulent eddies and miniature whirlpool formations. This hydrodynamic system is the cause for

localised scour and areas of deposition in and around the Harbour.

The tidal flows of the Dover Strait are faster on the ebb than on the flood, with the maximum flow

velocities typically occurring along the coastal margins.

The Ports dredging operations mean that sediment and its characteristics have been well

documented. Sediment samples submitted to Cefas to inform dredging disposal licences indicate that

sediment quality within the Port is good, and metal concentrations considerably low. Under the Ports

current disposal licence DHB are permitted to dispose of 499000 tonnes of material per annum, on a

disposal site in the English Channel. In addition to the dredging activity in the vicinity the baseline

suspended sediment concentrations are relatively high in the Dover Straits. Levels are dependant on

wave energy in the channel and vary with typical levels around 100-150mg/l.

2.1. Potential Issues

The installation of a tidal device may impact upon the current hydrodynamic regime potentially

affecting tidal currents and wave regimes in both the operational and instillation phases. These

affects may arise from the flow interacting with a structure redistributing energy, affecting flow

speeds, patterns and wave processes. These changes may then have the potential to alter sediment

transport as well as potentially affecting navigation. Due to the proposed scale of devices it is

anticipated that flow changes will be small scale and localised. Device manufacturers have estimated

that laminar flow returns within 10 times the distance of the length of the blade, this is expected to

be 60-80metres, device dependant. This suggests that any potential impacts are unlikely to influence

designated sites adjacent to the Port. However, hydrodynamic surveying will be undertaken and

assessed as part of the environmental appraisal.

Mounting during installation has the potential to remobilise sediments, however, due to the relatively

high baseline suspended sediment concentrations in the Straights it is anticipated that any impact

would be low. In addition due to the lack of heavy industry in the area it is anticipated that

remobilisation of toxic material will be negligible and therefore will not be considered further.

Direct: Changes to tidal propagation; changes to current speeds

Indirect: Changes to suspended sediment concentrations; changes to bed composition;

navigational considerations

2.2. Further Assessment

The hydrodynamics play an important role in the feasibility of the proposed project. Current

understanding comes in the form of the Port of Dover Tidal Atlas, at this stage data gathering is to be

undertaken and the tidal currents in the proposed location studied.

An Acoustic Doppler Current Profiler (ADCP) will be used to measure water current velocities over a

depth range. It is intended that the ADCP will be deployed on the seabed over a tidal cycle and

specific towed ADCP surveys carried out in areas which require further detail. The results of the

surveys will be modelled addressing flow speeds and directions. These models will initially aid

considerations in the feasibility study and support the selection criteria of devices to be piloted.

Subsequently, the models will also facilitate an assessment of the potential hydrodynamic alterations

to fully consider all the environmental parameters in support of the Marine Licence.

In addition to current velocity assessments water quality testing will be carried out to assess insitu

water quality measurements. An additional site will be included in the harbour water quality

monitoring programme in the tidal investigation zone. Water samples are collected by EMU Limited by

sampler just below the sea surface (approximately 0.5m). The samples are tested for total suspended

sediments (TSS), dissolved oxygen, temperature, salinity and pH, as well as microbial parameters;

Total Coliforms, Faecal Coliforms, Faecal Streptococci, and Salmonella.

3.0. BENTHIC ECOLOGY

A review of the benthic grab data and seabed habitat mapping made available by MESH (Mapping

European Seabed Habitats) figure 3 identifies that there are 3 main seabed habitat types adjacent to

the Harbour:

Sublittoral mixed sediments

Sublittoral sand

Circalittoral moderate rock & thin sediments

The proposed development location falling on sublittoral mixed sediments depths ranging from 10.5-

17.5 metres below chart datum.

Figure 3. Mapping European Seabed Habitats (MESH) EUNIS classification, habitat maps www.searchmesh.net

The Port’s environmental monitoring programme includes benthic grab sampling undertaken on a

quarterly basis from nine sites within and around the harbour (Figure 4). They consist of an array of

sediment types and physical environments. A Van Veen grab is used to take samples of the sites;

sediment type and consistency is recorded prior to samples being sieved using 1mm and 2mm mesh

sizes. Fauna is removed from the sieves and identified to species level where possible. These

quarterly benthic surveys dating back to 1994 and the extensive benthic invertebrate surveys carried

out for the Terminal 2 EIA have produced detailed benthic species lists of the port area.

Sublittoral sand

Sublittoral mixed

sediments

Circalittoral

moderate rock &

thin sediments

Figure 4. Benthic grab sample survey sites surveyed during the months of February, May, August and November since 1994

The benthic infauna and epifauna species identified from surveys are typical opportunistic species.

The dominating species being the bivalves Abra alba, Nucula nitidosa, and the polychaetes

Chaetozone gibber, Aphelochaeta marioni and Nephtys hombergii. The communities present are

representative of the dynamic port environment which is subject to maintenance dredging and heavy

vessel usage. The species listed are widespread in the English Channel and British coasts and are not

of local or national importance.

It should be noted that Sabellaria reef is known to exist along this stretch of the coastline, although

not identified in the Port, it is an important area of investigation.

3.1. Potential Issues arising during the Installation Phase

The installation phase may result in physical damage and disturbance from the laying of cables and

mounting of devices. As a device has yet to be chosen, the preferred method of mounting has yet to

be selected and benthic habitat will be taken into consideration during the feasibility study. The

installation activities may cause the mobilisation and dispersion of sediment, which could result in the

smothering of benthic communities and release of contaminants. Due to the tolerant nature of the

species in the locality, recolonisation would be expected with the rate dependant upon length of

disturbance. The effects are outlined below:

Direct: Seabed disturbance from cable laying and device installation; increased

suspended sediment; potential substratum loss from mounted devices

Indirect: Smothering of benthic habitat; accidental contamination from device failures or

collisions; changes in tidal flow and wave regime

3.2. Potential Issues arising from the Operational Phase

The potential impact to the seabed habitat and benthic ecology longer term, will vary depending upon

the chosen seabed mounting and maintenance regime; at this current stage a preferred method of

mounting and maintenance has yet to be selected. Abrasion and disturbance to the bed could result

from seabed anchor and mooring chain movements. The communities present are already subject to

regular disturbance caused by turbulent flows of water, dredging and vessel movements. The physical

mounting will create new structures available for colonisation and this could also attract invasive

species, and damaging bio-fouling. It is anticipated that this aspect will be incorporated into

discussions with manufacturers as it poses an efficiency issue as well as a significant maintenance

requirement.

The placement of cables has the potential to impact upon elasmobranchs, which are sensitive to

electromagnetic fields. The Environment Agency identified that knowledge from wind farm

installations suggests that the small scale nature and therefore power output is unlikely to be of

concern.

Direct: Seabed disturbance from programmed and reactive maintenance; increased

suspended sediment; substratum loss from attaching devices to the seabed

Indirect: Smothering of benthic habitat; accidental contamination from device failures or

collisions; changes in tidal flow and wave regime


The existing benthic fauna database provides sufficient data to understand the locality; further

investigation will provide more detail of the investigation zone. There are three proposed additional

benthic grab sample sites (Figure 5) these will be added to DHB’s current MMO Quarterly Benthic

Monitoring licence L/2012/00335/1 (Appendix 1). These samples will be collected along with the

current survey sites in the months of February, May, August and November for the duration of the

project commencing May 2013 as detailed in section 1.2. Sediment samples will be collected with a

Van Veen grab (0.1m²) in the absence of a sample the grab will be sent down again up to a

maximum of three times to ascertain similar sample sizes. Sediment type and consistency will be

recorded (Appendix 2) prior to sieving through 2mm and 1mm mesh sizes. Fauna will be collected,

identified and recorded. The survey should identify if any protected benthic species are present within

the proposed site and characterise in greater detail the habitat type. Multibeam data will also be

provided to give a graphic representation allowing any features to be identified, an important method

in which to identify Sabellaria reef.

Figure 5. Proposed additional benthic grab sample sites

It is anticipated that existing and proposed survey data will be sufficient to allow the significance of

the potential impacts of the project to be established in the environmental appraisal.

4.0. FISH & SHELLFISH

DHB undertakes beam trawling within the Outer Harbour with special dispensation from the MMO

every quarter to collect fish data and understand the seasonal variation within the harbour. A 10ft

benthic beam trawl with 4cm mesh net and shrimp cod end is used from the survey vessel ‘Diana’

following six pre-defined trawl lines (Figure 6). The shrimp cod end allows the collection of juvenile

fish and small invertebrates. The catch is identified, measured, recorded and returned to the sea. The

data collected identifies that the harbour area supports a diverse range of different species.

Echinoderms and crustaceans dominate the catch; common abundant species include brittlestars

(Ophiura), hermit crabs (Eupagurus bernhardus) and common gobys (Pomatoschistus microps).

Finfish make up 23% of the total individuals caught and key are the flatfish; common sole, flounder

and plaice appear at all stages of their lifecycle. The survey area is characteristically a mud/sand

habitat reflective of the species found. High level overviews provided by Cefas’ Fisheries Sensitivity

Maps indicate that common sole, flounder, plaice and sprat populations use the waters of the Dover

Strait as nursery and spawning grounds.

Figure 6. Trawling line locations in the outer Harbour shelf area, performed quarterly in the months of February, May, August and November since 1993

In addition to demersal surveys, pelagic fish surveys were undertaken as part of the Terminal 2 EIA

in the Western Docks in 2008 by EMU Ltd. They identified seven fish species across eleven sites and

recognised that fish were more likely to be found in close proximity to protective structures such as

walls, pontoons and slipways, the dominant species included juvenile sprat and bass.

Dover Harbour is a busy sea fishing venue, with anglers fishing from harbour structures. Static gear

fisheries for crab and lobster are operated in the local vicinity.

4.1. Potential Issues arising from the Installation Phase

During installation the proposed project has the potential to impact on the present fish habitat

through noise and vibration. This will be primarily dependant upon the chosen method of mounting,

however, it is expected that mobile fish species will move away and return after what is likely to be a

short term disturbance event particularly in this industrious locality. Installation activities also have

the potential for short term increased suspended sediment resulting from the activities of cable laying

and mounting. These impacts may have an adverse affect on some shellfish and fish species sensitive

to smothering. The high natural sediment load, active shipping zone and maintenance dredging

within the harbour suggests many species present are tolerant of sediment disturbance. The potential

effects are detailed below:

Direct: Seabed disturbance, noise and vibration from cable laying and device

installation; increased suspended sediment; small scale substratum loss, from attaching

devices to the seabed

Indirect: Smothering; loss of prey species; accidental contamination from device

failures or collisions; changes in tidal flow and wave regime


The impacts associated with the operational phase on fish species are largely associated with a

turbine and fish interaction. The proposed project has the potential to impact upon the passage of

fish species, and there is a risk of collision. A device will also create new structures available for

colonisation, therefore, there is the potential for structures to act as fish aggregation devices if not

maintained appropriately. Organism interactions with a device will be an influential consideration

throughout the device selection process and feasibility studies, as well as ascertaining appropriate

maintenance requirements.

Direct: Disturbance, vibration and noise during programmed and reactive maintenance;

suspended sediment; risk of collision

Indirect: Smothering; accidental contamination from device failures or collisions; habitat

exclusion


The data on fish species from trawl surveys adequately assesses areas within the harbour. It is

therefore proposed that a series of repeatable trawl surveys will be commissioned to survey outside

the harbour walls and within the vicinity of the proposed site. These benthic trawl surveys will be

carried out twice a year during July/August and November along three proposed survey lines as

detailed in the figure below. In addition as requested by the Environment Agency one pelagic trawl

survey will be undertaken during the summer period July/August.

Dispensation will be requested to use a shrimp cod end to catch juvenile fish and small invertebrates.

Figure 7. Three proposed trawl lines to be carried out twice a year in the vicinity of the investigation zone

The results from this site specific data along with findings from previous trawl surveys should present

sufficient evidence of the species present. The assessment of the effects of noise from the proposed

project will be undertaken through relating documented responses of species identified to the noise

anticipated. Various fish species have differing levels of sensitivity to noise impacts and therefore

avoidance. Understanding the numbers of noise sensitive fish, for example sprat and whiting will

enable an impact assessment. It should be noted that noise impacts from device installation and

operation are currently unknown and this aspect will be addressed in the environmental appraisal

through the selected device/s and mounting chosen from the feasibility study.

5.0. MARINE MAMMALS

There are two species of seal resident to local waters the common seal Phoca vitulina and grey seal

Halichoerus grypus; both species are present in colonies to the East of Dover. Seals are frequently

sighted within Dover Harbour, with both common and grey seals being identified. An Environmental

Reporting system records sightings of seals and cetaceans by Port staff; these records indicate that

seals feed and rest in and around the harbour and its artificial structures as can be identified from the

seal related environmental occurrences during 2012 (Table 1).

Figure 8. Drawing identifying areas with regular seal sightings

Table 1: Staff reported sightings and activities of seals in the port jurisdiction 2012. Environmental Occurrence database.

Date Quantity Location Behaviour/comments

11th Jan 1 Cruise 1 Swimming

25th Jan 2 Hoverport Swimming

8th Feb 1 Cruise 1 Swimming

16th Feb 1 Outer Harbour Fishing

12th March 1 Outer Harbour Fishing

30th March 1 Eastern Arm Swimming

9th April 1 Tidal Basin Eating

9th May 1 Tug Haven Eating

14th May 1 Hoverport Resting

16th May 1 Seafront Bathing in shallows

16th May 1 Eastern Arm Eating an eel

23rd May 1 Granville Entrance

Waiting at the entrance for it to open with an influx of fish

27th May 1 Tug Haven Swimming

11th June 1 Port Control Swimming

3rd July 2 Hoverport Eating

11th July 1 Dolphin Jetty Resting

10th Aug 1 Outer Harbour Swimming

15th Aug 1 Hoverport Resting

18th Sept 1 Cruise 3 Swimming, adolescent

26th Sept 1 Eastern Arm Swimming

28th Sept 4 Hoverport 2 pups, 2 adults resting

30th Sept 2 Hoverport Resting

4th Oct 1 Port Control Swimming

5th Oct 1 Hoverport Juvenile

8th Oct 2 Hoverport Resting

13th Oct 2 Hoverport 1 pup, 1 adult resting

The seals predominantly use the Western Docks particularly the marinas and are known to haul out

and rest on Cullins Yard disused slipway, pontoons and most commonly the old hoverport ramp,

where background levels of disturbance are high. Of note is that recent landside demolition work

carried out adjoining the hoverport ramp has not deterred seals from hauling out and resting in this

vicinity. Juveniles and adolescents are common and in November 2007 the British Marine Life Divers

Association positively identified grey seal pups one at two months old and one at around six months

old. The proposed tidal site has much less frequent sightings of seals in its immediate vicinity. Due to

their conservation status DHB recognise that the seals are a key concern and they will be an

important feature throughout the feasibility phase and pilot monitoring.

There are occasional sightings of cetaceans, on average 1 in every 3 years within the 1 nautical mile

jurisdiction of the Harbour. In general numbers of animals and species diversity in the southernmost

North Sea region are poor (Hammond et al., 2002; Reid et al., 2003).


It is anticipated that during any instillation works increased vessel movement would have a negligible

deterrence affect on cetaceans in the vicinity due to the current busy shipping zone and therefore will

not be further considered. Seals, however, frequent the busy port environment; depending on the

mounting and cable laying methodology this could cause disturbance and short term avoidance. With

an appreciation of this particularly active site and previous identification during disturbance activities,

it suggests that seals may well carry on passing in and out of the harbour avoiding the installation

activity area. Seals in the port are recognised to already avoid and pass alongside the regular

dredging activity and large vessel movements.

Direct: Vibration and increased noise; increased possibility of marine mammal coming

into contact with a vessel

Indirect: Accidental contamination from instillation failures, vessel collisions; potential

impacts to feeding resources

5.2. Potential issues arising from the Operational Phase

At this current time there is limited knowledge of the response of marine mammals around an

operating turbine. There is the potential for marine mammals to come into contact with a device, and

the possibility that possible device noise may deter species from the vicinity. It should be noted that

any noise impacts from operation are currently unknown and this aspect will be addressed in the

environmental appraisal through the selected device/s chosen from the feasibility study. It is

anticipated that, due to high background levels, marine mammals in the vicinity are likely to be

tolerant of some level of noise disturbance. The regular occurrence of seal sightings suggests these

would be the species of impact concern; the low number of cetacean sightings within the local

environment, particularly in the vicinity of the site, lessons the concern of an impact on these species.

Direct: Risk of collision with operating devices; disturbance during planned or reactive

maintenance

Indirect: Creation of a barrier to normal movements due to avoidance; accidental

contamination from device failures


Due to marine mammal’s conservation importance and the current uncertainties surrounding their

response to operating turbines, they are a key consideration in the project. DHB has an historical log

of marine mammal sightings which provides valuable data on of use of the ports jurisdiction. It is

anticipated that more thorough and site specific data will be required for the environmental appraisal.

The current system of marine mammal monitoring relies on port staff logging ‘wildlife’ sightings in the

Environmental Occurrence Reporting System. It is proposed that more formal specific monitoring

would be initiated to compliment the occurrence reporting. A Multiple sightings form will be provided

to Port Control and Tug Haven Staff (Appendix 3) and they will be trained how to use it. Port Control

and Tug Haven staff are best placed to carry out recording of the investigation zone, and areas where

seals are sighted more frequently. They both have a 24hour operations, proving valuable to monitor

any seals and their activities. These observations will remain in place during pilot installations

identifying any potential responses or changes.

The results will provide a more detailed view of how seals in particular use the vicinity of the

proposed site. Assessment will predominantly cover current knowledge from other device installations

and, importantly, observations during a pilot phase.

It should be noted that the occurrence system reporting will remain in its current form with staff

reporting sightings in the port jurisdiction.

6.0. ORNITHOLOGY

The harbour and proposed deployment site does not lie within a designated site for ornithological

interest. Surrounding Sites of Special Scientific Interest (SSSI) are recognised for their cliff nesting

species as well as migrant overwintering birds.

Since 2008 DHB has been undertaking breeding and overwintering bird surveys throughout both the

Western and Eastern Docks. Two full port surveys are carried out each month during the survey

periods October to February and March to May, over a high tide and a low tide. Birds are identified,

counted and mapped within the limits of the Port and within a 50 metre radius of the Port limits.

Observations also involve possible breading activity and flight paths if applicable. The database is

used on a regular basis to assess ornithological impacts of future developments.

The Port is largely urbanised with little vegetation and high levels of disturbance, consequently it

supports a limited number of bird species; surveys have identified 60 terrestrial and marine species

within the port vicinity. Gulls occur most frequently, with herring, common, black-headed and great

black-backed gulls numerically dominant. Cormorants and shags are also common throughout the

year. A variety of other marine birds are recorded during overwintering surveys in the relative shelter

of the harbour such as guillemots, black throated divers and great crested grebes (table 1). The

harbour is found to be a regular overwintering spot for numbers of the great crested grebe.

Table 1: Bird sightings within the Port of Dover

Most frequently sighted birds Marine species identified

Black-headed Gull Black-headed Gull

Carrion Crow Common Gull

Common Gull Common Tern

Cormorant Cormorant

Great Black-backed Gull Fulmar

Herring Gull Gannet

House Sparrow Glaucous Gull

Jackdaw Great Black-backed Gull

Lesser Black-backed Gull Great Crested Grebe

Pied Wagtail Great Northern Diver

Rock Pipit Guillemot

Turnstone Herring Gull

Kittiwake

Lesser Black-backed Gull

Little Grebe

Mediterranean Gull

Razorbill

Red-throated Diver

Shag

The Southern Breakwater adjacent to the proposed deployment site is a popular resting, breeding

and roosting site for a variety of the species commonly identified in the harbour such as shag,

cormorant, black-backed gull, common and herring gull.


Birds in the vicinity are likely to experience disturbance during the installation phase from device

installation works. Device mounting and cable laying is likely to cause disturbance through increased

noise and vibration. It is anticipated that, due to the nature of the environment, disturbance from

increased vessel movements would be of negligible impact and therefore will not be considered

further.

The location of a substation is not yet known but it is likely that it would be located on the Southern

Breakwater which is used as a breeding and roosting site for a variety of gulls, cormorants and shags.

This would result in disturbance during installation but it is anticipated that there will be no physical

loss of nesting, or roosting sites.

Direct: Disturbance through increased noise and vibration

Indirect: Potential impacts on feeding resources as a result of securing deployment

structures and laying cables


During the operational phase of the project there is the potential for bird species to collide with a

device; diving birds are more at risk of collision and several species of divers reside and visit the

locality. At this current stage the type of tidal device/s to be tested has not been confirmed, and,

therefore, blade type and depth are unknown. Organism interactions with a device will be an

influential consideration throughout the device selection process and feasibility studies. Although not

confirmed, it is anticipated that a substation will be located on the Southern Breakwater; maintenance

requirements and checks may have the potential to cause small scale disturbances on this popular

structure which already has occasional maintenance related visits.

Direct: Risk of collision with operating devices during foraging; reduction in foraging

habitat due to device presence; disturbance during planned or reactive maintenance

Indirect: Accidental contamination from device failures


DHB’s ornithology survey database provides data back to 2008, this is anticipated to be sufficient to

reflect the species present in the locality that may be affected. DHB’s ornithological monitoring

programme will also continue to provide data to later assess the impacts of a pilot project, identifying

any affects on the local populations.

The environmental appraisal will further assess the current data, and potential impacts of the

proposed project. Emphasis will be placed on the diving birds and species of conservation importance.

7.0. NAVIGATION

The Port of Dover is one of the worlds busiest international ferry ports, providing eight Ro-Ro ferry

berths as well as two cruise terminals, a cargo terminal, aggregates berth, tug haven and three yacht

basins. Consequently the vicinity of the project has high vessel densities and constant shipping

movements. All movements within one mile of the harbour are controlled by Dover Port Control and

vessels must report to Port Control prior to entering the port.

The selected investigation zone however has reduced usage; vessels tend to be smaller and are

predominantly pleasure craft.

7.1. Potential Issues

The proposed project has the potential to increase the risk of collision with installation vessels and

the operational devices and there is the potential to marginally displace pleasure craft movements

and disrupt navigation during the operational phase.

Any significant negative effects to shipping and navigation of the proposed project would make it

unviable for DHB as the harbour authority to take forward. The investigation zone was highlighted by

the Harbour Master as an area for potential deployment as it impacted least on shipping.

Consultations were also held with ferry operators who agreed that this area would impact them least.

It is anticipated that the location lessens the risk of a navigational incident, causing the least

disturbance to all port users.


Due to the chosen location it is unlikely that the project will have significant impact on commercial

navigation. However Port stakeholders will be consulted on the project during feasibility to ensure all

navigational requirements are considered. As discussed vessel movements in the vicinity are

infrequent and predominantly pleasure craft, therefore, further consultation into pleasure craft use

will be undertaken.

DHB’s Port Safety team will assess the safety of navigation with regards to collisions with installation

vessels and operational devices later in the feasibility process. The scope of further work will also

cover navigational safety with regards to navigation markers and the requirements of ‘Notice to

Mariners’.

8.0. DESIGNATED SITES

The Port of Dover is located between two Sites of Special Scientific Interest (SSSIs) and one Special

Area of Conservation (SAC), however the Harbour and proposed development location does not fall

within the boundaries of these designations. The proposed Marine Conservation Zones (MCZs), Dover

to Deal 11.1 and Dover to Folkestone 11.2, identified for their extensive chalk reefs, lie adjacent to

the Port in addition the Folkestone Pomerania 11.4 which lies off the coast to the West of the site.

The Folkestone Warren SSSI from Dover to Folkestone is designated for its range of geological

substrata providing an array of intertidal habitats which are colonised by a wide variety of marine

fauna and flora. The second SSSI located within 1km of Dover Harbour covers the coastline from

Dover to Kingsdown Cliffs. Similarly this site is designated for its geology and additionally its

physiography, and the variety of faunal and floral communities, including many rare species.

The Dover to Kingsdown Cliffs SAC lies within 1km of Dover Harbour and covers an area of

approximately 184ha; it is designated for its vegetated sea cliffs (Annex I habitat), for which this is

considered to be one of the best areas in the UK.

There are unlikely to be any significant risks to the surrounding designations; as discussed in the

hydrodynamic section, changes to flow patterns could impact upon sediment distribution, however,

any potential impact is likely to be localised and the risk to designations negligible. Other risks

associated with the sediment and disturbance during construction are also anticipated to be

extremely localised and of little significance to the surrounding designations. As discussed in section

2.0. sediment samples taken to inform dredging and other licences suggest that sediment has no

significant toxic constituents and therefore this impact will not be further considered.

The results of further data gathering will feed into the environmental appraisal to inform the

assessment of any potential impacts to the surrounding designations.

REFERENCES

Hammond, P. S., Berggren, P., Benke, H., Borchers, D.L., Collet, A., Heide-Jørgensen, M.P., Heimlich,

S., Hiby, A.R., Leopold, M.F. and Øien, N. (2002). Abundance of Harbour Porpoise and Other

Cetaceans in the North Sea and Adjacent Waters. Journal of Applied Ecology, 39: 361-376.

Appendix 1. MMO Marine Licence to carry out benthic samples grab sampling

Licence Number: L/2012/00335 Case Ref: MLA/2012/00310

Marine Licence

Licence Number: L/2012/00335 This is a licence issued by the Marine Management Organisation (MMO) on behalf of the Secretary of State to the licence holder named below to carry out activities for which a licence is required under Part 4 of the Marine and Coastal Access Act 2009. The licence is for licensable activities carried out as part of the project specified in Section 2 of this licence and is subject to the terms and conditions set out in this Licence. Licence Holder Name: Dover Harbour Board Address: Harbour House,

Marine Parade, Dover Kent CT17 9BU

Licence Date: Valid From 7th September 2012 Valid to: 6th September 2015 Date of issue: 7th September 2012 SMr Mark Kirby

+44 (0)191 376 2563 [email protected]

Appendix 2. Benthic Fauna monitoring form identifying the type of data collected with

each grab sample

Dover Harbour Board Environmental Database

Benthic Fauna Monitoring

Site No. Bucket No.

Full

Date: Depth: Half

Time: Tide: Empty

Comments:

Quantity Length (mm)

Comments:

Oxic [ ] Anoxic [ ]

Start location:

Finish location:

Common Name

Organic [ ] Inorganic [ ] Fine [ ] Grainy [ ]

Site Name:

Silt [ ] Mud [ ] Clay [ ] Sand [ ] Gravel [ ] Chalk [ ] Boulders [ ] Shelly Fragments [ ]

Odour [ ] Odourless [ ] Adhesive[ ] Compacted [ ] Loose [ ]

Sediment Description: (Tick relevant descriptive words)

Grabs Deployed:

Scientific Name

Appendix 3. Port of Dover Marine Mammal Sightings form provided to specific port staff

to record marine mammal sightings in the port

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