impacts on designated sites, drainage …...conservation handbook advises that semi-improved...

LONDON ASHFORD AIRPORT, LYDD (LAA)

August 2008

Prepared byParsons Brinckerhoff LtdAmber CourtWilliam Armstrong DriveNewcastle upon TyneNE4 7YQ

Prepared forLondon Ashford AirportLyddRomney MarshKentTN29 9QL

IMPACTS ON DESIGNATED SITES,DRAINAGE DITCHES AND GREATCRESTED NEWTS

Report Title : Impacts on Designated Sites, Drainage Ditchesand Great Crested Newts

Report Status : Final

Job No : HAG91877A/3.1

Date : August 2008

Prepared by : ......................................................Leanne Moses

Checked by : ................................Mark McLellan

Approved by : ................................Mark Mclellan

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IMPACTS OF THE RUNWAY EXTENSION ON DESIGNATED SITES, DRAINAGE DITCHES ANDGREAT CRESTED NEWTS

In December 2006, London Ashford Airport (Lydd) ("LAA") submitted a planning application for arunway extension (reference Y06/1648/SH) and a planning application for a new terminal building(reference Y06/1647/SH) supported by an Environmental Statement. Following consultation that tookplace at the beginning of 2007, LAA submitted in October 2007 Supplementary Information to furthersupport the two planning applications.

The Supplementary Information was consulted upon during Autumn/Winter 2007, with ShepwayDistrict Council ("SDC") requesting additional information in March 2008. The points in relation to theimpacts of the runway extension on designated sites, drainage ditches and great crested newts arereplicated below as follows:

Issue (Numbersas in SDC Table)

Designatedsite (pluspotentialandintended)

Request/clarification

1.Runwayextension anddesignatedsites

SAC, SSSI i. Provide information that explains how the length ofditch and grassland/arable land designated as SACwithin the proposed runway extension area wouldaffect that designation and any features.

ii. Provide calculations that show: (i) the area of theSSSI that will become paved runway; (ii) the area ofthe SSSI that will become runway strip1; (iii) the areaof the SAC that will become paved runway; and (iv)the area of the SAC that will become runway strip.

iii. Provide a plan of the proposed runway extension (at1:500 scale) that shows the proposed developmenttogether with designated site boundaries, existingditches, proposed ditches and habitat types (e.g.arable land, rough grassland, short grazedgrassland, etc).

iv. Please confirm the proposed runway strip will beunimproved grassland not cultivated farm land.

4. Great CrestedNewt terrestrialhabitat

SAC, SSSI,RamsarSite(intended)

i. Under the precautionary assumption that GCNs arepresent within the ditches of the runway extensionarea, clarify the area of potential terrestrial GCNhabitat (i.e. rough grassland) within the proposedrunway extension, both within and outside the SAC,SSSI and intended Ramsar Site.

ii. Clarify what mitigation or compensation measureswill be implemented for the loss of potentialterrestrial GCN habitat, to the degree that there is noreasonable scientific doubt that the measures areadequate, feasible and deliverable. In addition,assess whether any such measures are‘compensation’ or ‘mitigation’ in the context of theHabitats Directive.

6. Current runwaystrip

SAC, SSSI,Ramsar

i. Provide evidence from the CAA that there is noreasonable likelihood that the GCN pond located

1The ‘runway strip’ is interpreted as the ‘clear and graded’ or ‘clear’ areas around the pavedrunway; these areas are planted and maintained as grassland swards.

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Issue (Numbersas in SDC Table)

Designatedsite (pluspotentialandintended)


Site(intended)

within the current runway strip would need to bewholly or partly in-filled if the type and frequency ofaircraft movements changed to the levels envisagedin the development proposals.

ii. Clarify with the CAA the necessity, or otherwise, towiden the current runway strip in order toaccommodate the type and frequency of aircraftmovements envisaged under the developmentproposals.

iii. Clarify the necessity, or otherwise, of any worksrequired as a result of the proposed developmentswithin the current runway strip.

iv. If widening of the runway strip, works within it or in-filling of the GCN pond are reasonably foreseeable,clarify what effect this may have upon designatedfeatures of the SAC, SSSI and intended RamsarSite, such as GCN, Medicinal Leech and ‘perennialvegetation of stony banks’ (making use of NVC datafrom Natural England as necessary).Where significant adverse effects are reasonablyforeseeable, clarify what mitigation or compensationmeasures will be implemented (in consultation withNatural England), to the degree that there is noreasonable scientific doubt that the measures areadequate, feasible and deliverable. In addition,assess whether any such measures are‘compensation’ or ‘mitigation’ in the context of theHabitats Directive.

13. Ditches withinand aroundthe proposedrunwayextension


i. Clarify how a significant reduction in water qualitywithin the ditches in the area of the proposed runwayextension will be avoided as a result of the runwayextension, to the degree that there is no reasonablescientific doubt that the proposed measures areadequate, feasible and deliverable.

ii. Clarify what mitigation or compensation measureswill be implemented for the loss of ditches, to thedegree that there is no reasonable scientific doubtthat the measures are adequate, feasible anddeliverable. In addition, assess whether any suchmeasures are ‘compensation’ or ‘mitigation’ in thecontext of the Habitats Directive.

15. Ramsar Siteboundary

RamsarSite(intended)

i. Clarify with Natural England the likely boundary ofthe Ramsar Site, especially within the proposedrunway extension area and existing runway strip.

20. Water qualityanalysis ofGCN pond


i. Clarify with Natural England the need, or otherwise,for a chemical survey of the GCN pond adjacent tothe current runway strip. If this proves to bereasonably necessary, conduct the work and submitthe results.

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1 RUNWAY EXTENSION AND DESIGNATED SITES

1.1 Response to Comment 1 (i)Issue Designated

site (pluspotentialandintended)


1. Runwayextensionanddesignatedsites

SAC, SSSI i. Provide information that explains how thelength of ditch and grassland/arable landdesignated as SAC within the proposedrunway extension area would affect thatdesignation and any features.

1.1.1 To explain how the proposed runway extension may affect the SAC designation andany designated features, it is necessary to consider each designated featureseparately.

1.1.2 The Dungeness Special Area of Conservation (SAC) has been selected fordesignation based on three criteria.

1. The presence of an Annex I habitat; ‘annual vegetation of drift lines’2. The presence of an Annex I habitat; ‘perennial vegetation of stony banks’3. The presence of an Annex II species; great crested newts Triturus cristatus.

The purpose of the designation is to maintain, in favourable condition, the habitats forthe population of great crested newt. The designation does not include protection forthe animals themselves, which are protected separately by the Wildlife andCountryside Act 1981 (as amended).

1.1.3 The proposed runway extension is located to the north of the current runway. No landto the north of the runway is classified as ‘annual vegetation of drift lines’ or ‘perennialvegetation of stony banks’. Therefore, the only designation criterion that could beaffected by the runway extension is the presence of great crested newts and morespecifically, their aquatic or terrestrial habitat.

Great Crested Newt Aquatic Habitat1.1.4 The potential aquatic habitat for great crested newts at LAA comprises the ditch

network. The total length of the ditches which are proposed for removal is 1013m,283m of which is located within the Dungeness SAC.

1.1.5 Surveys carried out on behalf of LAA as part of the Environmental Statement (ES)dated December 2006 (reported in Chapter 10 of the 2006 ES for the runwayextension), indicate that the ditch length in question is “considered to represent poorgreat crested newt habitat” and that “no signs of the presence of this species wereidentified there during the surveys undertaken in July 2005 or 2006” (paragraph10.4.45 of Chapter 10 of the 2006 ES for the runway extension).

1.1.6 Therefore, while great crested newts are known to be present within the SACboundaries and in other parts of the airfield, the surveys show that that they do notappear to be present or breeding in the ditches that would be removed as part of therunway extension. Therefore, it is considered that removal of the ditch is unlikely toimpact upon the great crested newt population within the SAC.

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Great Crested Newt Terrestrial Habitat1.1.7 Great crested newts also have terrestrial habitat requirements. As stated at paragraph

10.6.3 of Chapter 10 of the 2006 ES for the runway extension, ‘habitats that would beaffected would be primarily semi-improved (rough) grassland (4.5 ha) and arablegrassland (13.6 ha)’. Following further assessment it has been calculated that theconstruction of the runway extension will involve less land take from these habitats(refer to the table in paragraph 2.1.4 below).

1.1.8 Arable land can provide suitable habitat for great crested newts, but is limited by anumber of factors. The Great Crested Newt Conservation Handbook (Froglife, 2001)gives examples of these limitations:

the use of pesticides can reduce terrestrial prey density; fertilisers may run off into ponds causing eutrophication; and ploughing, rolling, harrowing and similar farming practices may inhibit

dispersal.

1.1.9 In addition to the limitations specified above, arable land also tends to comprise largemonocultures of certain crop species. This is not ideal great crested newt habitat asthey prefer structurally varied habitat.

1.1.10 Taking the above into consideration, the loss of arable land, even a relatively largearea, is not considered to have a significant negative impact on great crested newts.

1.1.11 The other habitat type to be impacted is referred to at paragraph 10.6.4 of the 2006ES for the runway extension as semi-improved grassland. The Great Crested NewtConservation Handbook advises that semi-improved grassland is a valuable terrestrialresource to great crested newts. However, it is of most value when in a mosaic withwoodland and ponds. The SAC designation acknowledges that in the Dungeness SACthere is very little woodland (approximately 1% of the SAC is woodland according tothe citation). It states that the important terrestrial habitat is ‘open vegetated shinglewith scrub’. This reduces the potential suitability of the semi-improved grasslandpresent across the SAC. Furthermore, only a small area of potentially suitable habitatwill be affected by the proposal (2.34ha) further reducing any potential impacts on thegreat crested newt population within the SAC. The majority of the 2.34ha will be partof the runway strip, meaning that no real change to the land will occur. Only 0.23ha ofthe SAC will be affected by hard paving of the runway extension.

1.1.12 In summary, the integrity of the SAC will not be adversely affected by the proposedrunway extension. Criteria 1 and 2 as specified in Section 1.1.2 are at no risk of beingimpacted upon by the proposals. Furthermore, great crested newts, specifically theirhabitat within Dungeness SAC will not be adversely affected by the insignificant lossof habitat.

1.2 Response to Comment 1 (ii)Issue Designated




SAC, SSSI ii. Provide calculations that show: (i) thearea of the SSSI that will becomepaved runway; (ii) the area of theSSSI that will become runway strip;(iii) the area of the SAC that willbecome paved runway; and (iv) thearea of the SAC that will becomerunway strip.

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1.2.1 There will be very little land use change as a result of the proposed runway extension.The proposed runway footprint currently comprises semi-improved grassland andagricultural land. The proposed extension will comprise a paved area and a runwaystrip (clear and graded area comprising semi-improved grassland).

Table 1: The potential change in land use within the SSSI under the runway extensionproposals

Area (ha) Area as a percentage ofthe entire SSSI (%)

Paved Area 1.62 0.018Runway Strip 11.23 0.12Total 12.85 0.14

1.2.2 As shown in Table 1 above, only 0.14% of the total SSSI will potentially be affected bythe proposed runway extension. However, only the paved area will result in asignificant change in habitat (0.018%).

Table 2: The potential change in land use within the SAC under the runway extensionproposals

Area (ha) Area as a percentage ofthe entire SAC (%)

Paved Area 0.23 0.007Runway Strip 1.59 0.049Total 1.82 0.056

1.2.3 As shown in Table 2 above, only 0.056% of the total SAC will potentially be affectedby the proposed runway extension. However, it is anticipated that only the paved areawill result in a significant change in habitat (0.007%). It should be noted that followingthis reassessment, the extent of the land take from the SAC has decreased from0.067% to 0.056% (or 2.17ha to 1.82ha). Accordingly, the figures in Table 2 abovesupersede those contained within the Statement to Inform on the predicted impactsfrom the proposed runway extension on the SAC.

1.2.4 As the SSSI land is also land that is designated as the SAC, so the total land takerequired is the total of land taken from the SSSI.

1.3 Response to Comment 1(iii)Issue Designated




SAC, SSSI iii. Provide a plan of the proposed runwayextension (at 1:500 scale) that shows theproposed development together with designatedsite boundaries, existing ditches, proposedditches and habitat types (e.g. arable land,rough grassland, short grazed grassland, etc).

1.4 Figure 1A-1C shows the current LAA boundaries and runway, the proposed runwayextension, the SSSI and the SAC. The SPA is not shown as the 1:500 scale requestedabove is too large to show the nearest point of the SPA to LAA (approximately 800mto the south east of the runway extension).

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1.5 No proposed Ramsar site boundaries have been released for public consultation byNatural England.

1.6 Response to Comment 1(iv)Issue Designated

site (pluspotential andintended)


1. Runwayextension anddesignatedsites

SAC, SSSI iv. Please confirm the proposed runway strip will beunimproved grassland not cultivated farm land.

1.7 The clear and graded area and the RESA, which forms the proposed runway strip, willcomprise semi-improved grassland not cultivated farmland. This grassland will bemaintained so that it does not exceed approximately 30cm in height, required by CAACAP 772.

2 GREAT CRESTED NEWT TERRESTRIAL HABITAT

2.1 Response to Comment 4(i)Issue Designated



4. GreatCrestedNewtterrestrialhabitat


i. Under the precautionary assumption thatGCNs are present within the ditches of therunway extension area, clarify the area ofpotential terrestrial GCN habitat (i.e. roughgrassland) within the proposed runwayextension, both within and outside the SAC,SSSI and intended Ramsar Site.

2.1.1 In addition to semi-improved (rough) grassland, arable land also provides potentiallysuitable terrestrial habitat and has been included within the tables below.

2.1.2 Table 3 below shows the area of potential terrestrial great crested newt habitat withinthe proposed runway extension footprint (the term "footprint" comprises both thepaved area and the runway strip) and the extent to which each habitat falls within thedesignated SAC boundary.

Table 3: The land use areas within and outside of the SAC boundaries.Area withinSAC (ha)

Area outside ofSAC (ha)

Total (ha)

Semi-improved (rough)grassland within runwayfootprint

0.49 2.68 3.17

Arable 1.33 8.35 9.68Total 1.82 11.03 12.85

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2.1.3 Table 3 above shows that approximately 1.82 hectares (ha) of potential terrestrialgreat crested newt habitat within the SAC may be potentially affected by the proposedrunway extension. This is equivalent to 0.056% of the entire SAC and any potentialimpacts are not considered to affect the integrity of the SAC in relation to great crestednewts and their habitat. Section 1.1 above provides further details of the potentialimpacts of the proposed runway extension on great crested newt terrestrial habitat.

2.1.4 Table 4 below provides data for the area (ha) of potential terrestrial great crested newthabitat within the proposed runway extension footprint and the extent to which eachhabitat falls within the designated SSSI boundary.

Table 4: The land use areas within and outside of the SSSI boundaries.Area withinSSSI

Area outside ofSSSI

Total

Semi-improved (rough)grassland within runwayfootprint

3.17 0 3.17

Arable 9.68 0 9.68Total 12.85 0 12.85

2.1.5 Table 4 above shows that approximately 12.85 ha of potential terrestrial great crestednewt habitat within the SSSI may be affected by the proposed runway extension. Thisis equivalent to only 0.14% of the entire SSSI and therefore the integrity of the SSSI inrelation to great crested newts and their habitat would not be significantly affected.

2.1.6 Although details of the proposed Ramsar site have not yet been released into thepublic domain it has been assumed for the purposes of this Report that LAA in itsentirety falls within the proposed designation. It is also assumed that the total area ofthe pRamsar will be equal to that of the SSSI. Therefore, the calculations in Table 4above provide a reasonable ‘worst case’ calculation of the area of the pRamsar sitewhich may potentially be affected. Again, only 0.14% of the entire pRamsar would beaffected and this is not considered to affect the integrity of the pRamsar in relation togreat crested newts and their habitat.

2.2 Response to Comment 4 (ii)Issue Designated



4. GreatCrestedNewtterrestrialhabitat

SAC, SSSI,Ramsar Site(intended)

ii. Clarify what mitigation or compensationmeasures will be implemented for the loss ofpotential terrestrial GCN habitat, to the degreethat there is no reasonable scientific doubt thatthe measures are adequate, feasible anddeliverable. In addition, assess whether any suchmeasures are ‘compensation’ or ‘mitigation’ in thecontext of the Habitats Directive.

2.2.1 It has been established that the proposed runway extension will not affect the integrityof the SAC (or pRamsar) and as such compensation measures in the context of theHabitats Directive are not required.

2.2.2 However, mitigation measures are proposed as part of the requirements underSchedule 4 of the Town and Country Planning (Environmental Impact Assessment)Regulations 1999 to describe measures to prevent, reduce and, where possible, offset

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any significant adverse effects on the environment. The EU Commission guidancepaper Article 6(4) Jan 2007 provided by Natural England defines mitigation as follows:

Mitigation Measures - in the broader sense, are those measures which aim tominimise, or even cancel, the negative impacts on a site that are likely to arise asa result of the implementation of a plan or project. These measures are anintegral part of the specifications of a plan or project.

2.2.3 A summary of the mitigation measures which will be implemented for the loss ofpotential terrestrial great crested newt (GCN) habitat is provided below.

2.3 Mitigation Measures – Relating directly to the construction of the runwayextension

2.3.1 The runway extension has been designed in such a way as to avoid sensitivereceptors wherever possible. Despite this, some potential terrestrial GCN habitatwould be removed. Mitigation measures would be implemented to reduce anypotentially detrimental impacts of construction on the remaining habitat.

2.3.2 A Construction Environmental Management Plan (CEMP) will be developed detailingbest practice mitigation across a range of construction activities. Implementation of theCEMP will minimise any negative impacts which the construction of the proposedrunway extension may have on the surrounding habitat. An outline CEMP for theproposed runway extension is submitted alongside this report in the 2008Supplementary Environmental Information.

2.4 Mitigation Measures – Independent of the construction of the runway extension

2.4.1 The following mitigation measures would be implemented to offset the potentialimpacts of the loss of potential terrestrial GCN habitat which would occur when therunway extension is constructed.

2.4.2 GCN terrestrial habitat will be improved by providing refugia and over-wintering siteson the LAA site as shown in Figure 2. Refugia will be constructed using one or all ofthe methods below, as detailed within The Great Crested Newt ConservationHandbook:

Mulching – providing a litter layer of bark mulch, preferably 100mm or moredeep.

Logs – log piles can be placed in shady positions. Turf and soil can be placedover the top to provide a more stable habitat.

Stones and rocks – can be used in a similar way to logs.

2.4.3 The refugia will be placed no further than 150m from Pond A or the smaller ponds inthe area. However, care will be taken to ensure that the refugia are at a sufficientdistance from the ponds so that they are not at risk in the event that the ponds flood.

3 CURRENT RUNWAY STRIP

3.1 Response to Comment 6(i)Issue Designated

site (pluspotential andintended)


6.Current

SAC, SSSI,Ramsar Site

i. Provide evidence from the CAA that there is noreasonable likelihood that the GCN pond located

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runwaystrip

(intended) within the current runway strip would need to bewholly or partly in-filled if the type and frequency ofaircraft movements changed to the levels envisaged inthe development proposals.

3.1.1 Pond A will not be in-filled, either partially or in its entirety, as a result of thedevelopment proposals.

3.2 Response to Comment 6(ii)

Issue Designatedsite (pluspotential andintended)


6. Currentrunwaystrip


ii. Clarify with the CAA the necessity, or otherwise, towiden the current runway strip in order toaccommodate the type and frequency of aircraftmovements envisaged under the developmentproposals.

3.2.1 LAA have confirmed that the width of the runway strip will not be altered as a result ofthe development proposals.

3.3 Response to Comment 6(iii)

Issue Designatedsite (pluspotentialandintended)


6. Currentrunway strip


iii. Clarify the necessity, or otherwise, of any worksrequired as a result of the proposeddevelopments within the current runway strip.

3.3.1 No works are proposed within the current runway strip. All works required for therunway extension are detailed within the planning application for the runway extension(Y06/1648/SH).

3.4 Response to Comment 6(iv)



6. Current runwaystrip


iv. If widening of the runway strip, works withinit or in-filling of the GCN pond arereasonably foreseeable, clarify what effectthis may have upon designated features ofthe SAC, SSSI and intended Ramsar Site,such as GCN, Medicinal Leech and

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‘perennial vegetation of stony banks’(making use of NVC data from NaturalEngland as necessary).Where significant adverse effects arereasonably foreseeable, clarify whatmitigation or compensation measures willbe implemented (in consultation withNatural England), to the degree that thereis no reasonable scientific doubt that themeasures are adequate, feasible anddeliverable. In addition, assess whetherany such measures are ‘compensation’ or‘mitigation’ in the context of the HabitatsDirective.

3.4.1 The runway strip at LAA will be retained in its current form following completion of therunway extension. The current runway strip does not require any works within it, and itis not proposed, nor required, for it to be widened.

3.4.2 The GCN pond (Pond A) will not be in-filled, either partially or in its entirety, as aresult of the development proposals.

4 DITCHES WITHIN AND AROUND THE PROPOSED RUNWAY EXTENSION

4.1 Response to Comment 13 (i)



13. Ditcheswithin andaround theproposedrunwayextension


i. Clarify how a significant reduction in waterquality within the ditches in the area of theproposed runway extension will be avoidedas a result of the runway extension, to thedegree that there is no reasonablescientific doubt that the proposedmeasures are adequate, feasible anddeliverable.

4.1.1 The potential impact of the proposed runway extension on the water quality within theditch network can be divided into construction and operational impacts.

4.1.2 During operation, aircraft related pollutants and sediments will be collected by oilseparators and silt traps respectively, which will be part of the integral design of therunway extension. These services will be maintained regularly by LAA and thematerial disposed of at an appropriate facility.

4.1.3 During construction, a Construction Environmental Management Plan (CEMP) will befollowed. Implementation of the CEMP will minimise any negative impacts which theconstruction of the proposed runway extension may have on the surrounding ditches.

4.1.4 Full details of all mitigation measures which would be implemented during constructioncan be found within the outline CEMP submitted with the 2008 SupplementaryInformation. They include:

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measures to prevent sedimentation within the ditch network;

details of refuelling procedures and oil interceptors to prevent hydrocarboncontamination; and

the storage procedure for spoil to prevent run-off.

4.2 Response to Comment 13 (ii)



13. Ditcheswithinandaroundtheproposedrunwayextension


ii. Clarify what mitigation or compensationmeasures will be implemented for the loss ofditches, to the degree that there is noreasonable scientific doubt that the measuresare adequate, feasible and deliverable. Inaddition, assess whether any such measuresare ‘compensation’ or ‘mitigation’ in thecontext of the Habitats Directive.

4.2.1 It has been established that the proposed runway extension will not affect the integrityof the SAC (or pRamsar) and as such compensation measures in the context of theHabitats Directive are not required.

4.2.2 However, LAA will be undertaking mitigation measures that are independent of thephysical runway extension works and outside the proposed development area in orderto offset the loss of ditches. These measures comprise the creation of new ditches,the improvement of existing ponds and the creation of new scrape ponds.

4.2.3 In accordance with CAA safety requirements, it is necessary for any proposed ditchand pond creation to be undertaken outside the 105m safety exclusion zone (105mfrom the centre line of the runway). The area between the 105m safety exclusion zoneand airport boundary is designated as the Dungeness Special Area of Conservation(SAC) as shown on Figures 1A-1C. SACs are protected by the Habitats Directive (asamended) from works that may have a negative effect on the designation and thedesignated features. For this reason, Natural England will be consulted before anyworks take place. The aim of this consultation will be to ensure compliance with legalrequirements and agree habitat creation proposals which will benefit the SAC.

4.2.4 Netting will be placed across all new ditches to discourage bird use and reduce therisk of bird strike. However, to ensure continued access for mammals such as watervole and otter, the netting will be raised slightly from ground level on a series ofwooden stakes thus forming a gap between the net and ground. The net will besufficiently high and pulled taught to prevent animals becoming entangled.

4.2.5 There are two types of ditch which will be created to replace those being lost:

i. Drainage ditches (Sewers)

4.2.6 Drainage Ditches (Sewers) will be created as shown in Figure 2. These ditches will beapproximately 1256m in length as stated in paragraph 2.1.6 of the Statement to Informfor the proposed runway extension submitted in October 2007 (this is 6m longer thanthat proposed at paragraph 10.8.4 of the 2006 ES for the runway extension) and will

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follow the northern edge of the runway. The new drains will contribute to the drainageof the site in the same way as the existing ditches and will play a role in balancingwater levels throughout the area. Further design details of these ditches are providedbelow. These ditches will be maintained as sewers and are unlikely to provide idealhabitat for species observed on site. For this reason an additional ditch will be createdwhich will focus on enhancing the biodiversity across the site.

ii. A ditch designed to enhance the biodiversity across the LAA site.

4.2.7 The proposed length of the new ditch, designed to enhance the biodiversity on theLAA site, will be approximately 450m. The new ditch will be located beyond therunway safety zone, but within the airport boundary. The proposed ditch will link twoexisting ditches improving the connectivity of the ditch network. This connectivity willincrease the ease with which species can migrate between the ditches as well asincreasing the amount of habitat available.

4.2.8 Ditch profile: The profile of the ditch is important for a number of species includingwater vole and medicinal leech. There are a number of factors that need to beconsidered.

4.2.9 Depending on the substrate which forms the edges of the ditch, it may be necessaryto reinforce the sides of the ditch in order to maintain the desired profile. Ifreinforcement is required then suitable burrow access will be need to be provided forwater voles.

4.2.10 The slope of the bank is also important, as if it is too steep it may prevent access toand from the ditch for certain species. However if this is too shallow then water voleswill not be able to make burrows. One suggestion is a small shelf just below the watersurface to act as a platform for fauna to use and for floral species to grow on.

4.2.11 Figure 3 shows details of the proposed profile of the ditch as well as suggested bankside vegetation.

4.2.12 Bank-side vegetation: Sympathetic management of standing water to balanceecology with functionality is needed. This will involve:

Management of the ditches on a 2-year cycle with half of the channel beingmanaged each year;

Management during late summer or early autumn; Cutting vegetation in 30m alternate sections, leaving the adjacent 30m

section uncut until the following year; Depositing soil away from the bank to avoid smothering the bank side; and Leaving spoil for 24 hours to allow amphibians and invertebrates to return to

the water.

4.2.13 Target species: The main target species for the new ditches are medicinal leech. It ishoped that medicinal leech may migrate from the existing ditch network into the newditch.

4.2.14 Medicinal leech habitat will be maintained by ensuring that the temperatures of thewater bodies they inhabit remain unchanged. Medicinal leech are reliant on waterbodies which have a higher than average spring/summer temperature for them to beable to breed. To avoid changing the water temperature the size of the water body willbe maintained as will the flow and source of water.

4.2.15 Medicinal leech also require animals on which to feed. In the absence of cattle andbirds, which can not be allowed within the airport boundaries for safety reasons,medicinal leeches can also feed on amphibians. Therefore amphibians should beencouraged to use the ditch network.

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4.2.16 Other species of note are known to be present in the existing ditch system. Theseinclude the small red-eyed damselfly Erythromma viridulum not previously recordedfrom Dungeness and a recent addition to the British list of invertebrate species, threescarce Orthoptera, a RDB3 water beetle, a Nationally Scarce soldierfly, a variety ofBagous species, a rare wasp that parasitizes soldierflies, the bee-wolf Philanthustriangulum formerly regarded as very rare but now widespread and a priority BAPspecies, the carder bee Bombus humilis. The new ditch design is likely to provideappropriate habitat for all of these invertebrates.

4.2.17 Pond Improvements

4.2.18 Pond A and a series of smaller ponds to the north east of Pond A are known to havecontained great crested newts in the past. The locations of the ponds are shown inFigure 2. In 2004, 12 great crested newts were recorded in the smaller ponds butnone were recorded during the 2006 surveys. A possible reason for thedisappearance of great crested newts within these ponds could be the noted presenceof fish. There are several ways that these ponds and Pond A could be improved toencourage an increase in the size and range of the great crested newt populationwithin the SAC. These include:

Fish eradication

Maintaining vegetation

4.2.19 Fish eradication: This may be the most important factor in establishing great crestednewts in the smaller ponds where they were found in 2005. The Great Crested NewtConservation Handbook suggests four methods for eliminating fish from a pond:

Netting; Draining down; Electrofishing; and Chemical treatment

4.2.20 All of these methods may be subject to a Natural England (NE) licence as there is thepotential for them to disturb a great crested newt population; NE would therefore beconsulted on the choice of method to remove fish.

4.2.21 Maintaining vegetation: It is important that water bodies have areas of open waterwhere great crested newts can perform mating displays. Species such as reedmacewould be controlled to ensure that they do not become heavily established in a pondas this would result in shading out other plant species which great crested newts useto lay their eggs.

4.2.22 Reeds and excess floating and aquatic vegetation would be removed each autumn.Any trees/shrubs will also be cut back to prevent shading and also from droppingleaves into the pond. Leaf litter will be placed in an area away from the pond toprovide refugia for great crested newts.

New scrapes

4.2.23 The location of new water bodies tailored towards providing terrestrial habitat for greatcrested newts has been carefully considered. Ideally water bodies should be createdwithin close proximity of a known great crested newt pond such as Pond A. Therefore,a series of scrape ponds are proposed within 500m of Pond A. The Great CrestedNewt Conservation Handbook states that where possible the new aquatic habitatshould be located near to woodland, grassland and hedgerows to provide greatcrested newts with terrestrial habitat and foraging grounds

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4.2.24 A series of scrapes will be created which will provide connective habitat for greatcrested newts as shown in Figure 2 (labelled as "improved ponds").

4.2.25 The new scrapes will lie within the Dungeness Special Area of Conservation (SAC).LAA acknowledge that SACs are protected by law from works that will cause anegative effect on their designated features. Although, the new scrapes have thepotential to enhance the SAC, Natural England will be consulted on this issue beforeany works take place to ensure that the measures will benefit the SAC.

4.2.26 The side of the scrapes will be shallow to allow easy access to and from the waterbody. The Great Crested Newt Handbook provides no recommendations for the shapeof the scrape, but advises that “ponds of less than about 25 square meters surfacearea tend to have insufficient depth and volume to allow many great crested newtlarvae to survive”. Occasional drying up of the scrapes is acceptable as it can kill fishwhich would predate great crested newt larvae. However, the scrapes will be linedwith a waterproof membrane as necessary to prevent them drying out more frequentlythan once every three years. If the scrapes are still drying out then their size anddepth may need to be altered so that they retain water for longer periods.

4.2.27 Figure 2 shows the proposed locations of the scrapes and the location of currentponds and ditches. Figure 3 shows the profile of the scrape as well as suggestedplanting species, these are discussed in more detail below.

4.2.28 As the scrapes are within an airport boundary they will have to have netting placedabove them to discourage birds from using them. This will also be of benefit to greatcrested newts as it will minimise the chances of fish eggs being transferred on birdsfeet. It will also prevent the degradation of the water and vegetation by waterfowl.

4.2.29 Planting: The scrape will either be left for floral species to colonise naturally orsuitable floral species will be planted as necessary. Natural colonisation can take along time and planting is likely to take place.

4.2.30 These plants will not only provide cover and egg laying material for the great crestednewts, but will also encourage invertebrate species upon which they feed.

4.2.31 As suggested in the Great Crested Newt Conservation Handbook, marginal and fullyaquatic floral species will be planted.

4.2.32 Only native species will be planted in the scrapes as non-native species may beinvasive and rapidly colonise them, choking out other species. All individual plants willbe checked to ensure that fish eggs are not being transferred with the plant into thescrape.

Mitigation Summary

4.2.33 It has been established that the proposed runway extension will not affect the integrityof the SAC and as such compensation measures in the context of the HabitatsDirective are not provided.

4.2.34 However, mitigation measures are proposed as part of the requirements underSchedule 4 of the Town and Country Planning (Environmental Impact Assessment)Regulations 1999 to describe measures to prevent, reduce and, where possible, offsetany significant adverse effects on the environment. However, The EU Commissionguidance paper Article 6(4) Jan 2007 provided by Natural England defines mitigationas follows:

Mitigation Measures - in the broader sense, are those measures which aim tominimise, or even cancel, the negative impacts on a site that are likely to arise asa result of the implementation of a plan or project. These measures are anintegral part of the specifications of a plan or project.

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4.2.35 A summary of the mitigation will be implemented for the loss of ditches is providedbelow.

Mitigation Measures – Relating directly to the construction of the runwayextension

4.2.36 The runway extension has been designed in such a way as to avoid sensitivereceptors wherever possible. Despite this some ditches are proposed for removal as aresult of the proposed runway extension. Mitigation measures will be implemented toreduce any potentially detrimental impacts of construction on the remaining habitat. AConstruction Environmental Management Plan (CEMP) will be developed detailingbest practice mitigation across a range of construction activities. Implementation of theCEMP will minimise any negative impacts which the construction process may haveon the surrounding grassland. An outline CEMP for the proposed runway extension issubmitted with the 2008 Supplementary Information.

4.2.37 The extent and duration of construction activities “within and adjacent to thewaterbodies/drainage ditches will be minimised to reduce the severity of the impactsresulting from silt disturbance” (ES, 2006; Section 10.8.4). This will be achievedthrough the CEMP.

4.2.38 “To reduce the risk of siltation and contamination of watercourses during operation,vegetated ditch banks will be enhanced” (ES, 2006; Section 10.9.2). Additionalattenuation ponds will also be created to trap silt and/or other potential contaminants,allowing them to degrade before reaching the main water bodies.

4.2.39 As well as the construction mitigation measures stated above, surface run-off from therunway during operation will also be controlled.

4.2.40 Aircraft related pollutants and sediments will be collected by the oil separators and silttraps respectively which are an integral design of the runway extension. Theseservices will be maintained regularly by LAA and the material disposed of at anappropriate facility.

4.2.41 The recent development of the attenuation and reedbed treatment pond, with itspollution interceptors and the airports ongoing commitments to improving sitedrainage, as well as improved environmental management planning, means that anyimpacts in the drainage ditches are expected to be of minor adverse significance.

Mitigation Measures – Independent of the construction of the runway extension

4.2.42 The following mitigation measures will be implemented to offset the loss of ditcheswhich will occur as a result of the proposed runway extension.

4.2.43 “Restoration and additional management of aquatic bank side vegetation will beundertaken to maximise the ecological interest of the drainage ditches” (ES, 2006;Chapter 19).

4.2.44 Drainage ditches (Sewers) will be created as shown in Figure 2. These ditches will beapproximately 1256m in length as stated in paragraph 2.1.6 of the Statement to Informfor the proposed runway extension submitted in October 2007. They will contribute tothe drainage of the site in the same way as the existing ditches and will play a role inbalancing water levels throughout the area.

4.2.45 An additional ditch will be created which will focus on enhancing the biodiversityacross the site. This ditch will be approximately 450m in length. The proposed ditchwill link two existing ditches improving the connectivity of the ditch network. Thisconnectivity will increase the ease with which species can migrate between theditches as well as increasing the amount of habitat available. This ditch will be

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designed to support medicinal leach and other rare invertebrates including the carderbee Bombus humilis.

4.2.46 Existing ponds known to contain great crested newts in the past, will be improved toencourage an increase in the size and dispersal range of the great crested newtpopulation within the SAC. Improvement measures will include fish eradication andmaintenance of suitable vegetation.

4.2.47 A series of scrape ponds will be created within 500m of Pond A. These scrapes will bedesigned to provide connective habitat for great crested newts.


Issue Designated site(plus potential andintended)


15. RamsarSiteboundary

Ramsar Site(intended)

i. Clarify with Natural England the likelyboundary of the Ramsar Site, especiallywithin the proposed runway extensionarea and existing runway strip.

4.3.1 Natural England have advised that no information on the potential proposed Ramsarsite boundaries have been released for public consultation.

4.3.2 For the purposes of this impact assessment it has been assumed that LAA in itsentirety falls within the proposed Ramsar site boundary and that all species andhabitats cited within the SSSI, SPA and SAC designations are included within theproposed Ramsar citation.


IssueDesignatedsite (pluspotentialandintended)


20. Waterqualityanalysisof GCNpond


i. Clarify with Natural England the need, orotherwise, for a chemical survey of the GCNpond adjacent to the current runway strip. If thisproves to be reasonably necessary, conduct thework and submit the results.

4.4.1 The “GCN Pond” referred to above is referenced in application documents andelsewhere in this report as ‘Pond A’. Natural England have specified that “a baselinechemical survey of the pond would be useful” and have suggested that the followinginformation should be collected; pH, nutrient content (N and P), presence of de-icercontamination, salts, heavy metals and oils.

4.4.2 Water samples from the pond were collected on July 22nd 2008 and dispatched foranalysis by Severn Trent Water Laboratories. The results of the analysis areappended to this report (Appendix A).

4.4.3 The results are consistent with a good quality freshwater pond; all of the measuredchemical parameters fall within the Environmental Quality Standards (EQS) levelsexpected for a water body of this type. There is no measurable hydrocarboncontamination.

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4.4.4 Additional comparison was made to the EC Freshwater Fish Directive (78/659/EEC)and in the EC Dangerous Substances Directive (76/464/EEC and DaughterDirectives). All measured parameters complied with the requirements of a freshwaterbody capable of supporting fish and other aquatic flora and fauna.

4.4.5 This baseline analysis will provide a useful benchmark for water quality at Pond A, andit is proposed that this sampling and analysis procedure is repeated every six monthsfrom the commencement of development.

5 RELATIONSHIP TO THE 2006 ENVIRONMENTAL STATEMENT AND 2007SUPPLEMENTAL INFORMATION

5.1.1 This Report should be read in conjunction with:-

Chapter 10 of the 2006 Environmental Statement for both the Terminal Buildingand the Runway Extension; and

Statements to Inform on the Predicted Impacts from the Proposed TerminalBuilding and Runway Extension at LAA on the Dungeness SAC contained inVolume 4 of the 2007 Supplemental Information.

5.1.2 The conclusions of this Report re-affirm the conclusions within the 2006Environmental Statements, which assessed the likely impact of the proposeddevelopments on designated sites, drainage ditches and great crested newts to below. The conclusions of this Report also re-affirm the conclusions of the Statements toInform, which concluded that the proposed developments would not adversely affectthe integrity of the SAC.

Appendix A

Results of the chemical analysis of ‘Pond A’

Parameter Units 1 2Cadmium , Total as Cd ug/l 0.9 0.8Cadmium, Filtered as Cd ug/l 0.8 <0.5Calcium , Total as Ca mg/l 51 89Chromium , Total as Cr ug/l <5 <5Chromium, Filtered as Cr ug/l <5 <5Copper , Total as Cu ug/l 15 10Copper, Filtered as Cu ug/l <5 <5Lead , Total as Pb ug/l 7 <5Lead, Filtered as Pb ug/l <5 <5Magnesium, Total as Mg mg/l 13 14Nickel , Total as Ni ug/l <5 <5Nickel, Filtered as Ni ug/l <5 <5Potassium , Total as K mg/l 6.6 7.7Sodium , Total as Na mg/l 55 54Zinc , Total as Zn ug/l 34 68Zinc, Filtered as Zn ug/l <5 <5

pHpH

Units 8.1 7.6Conductivity- Electrical 20C uS/cm 485 599Ammoniacal Nitrogen as N mg/l <0.3 <0.3Chloride as Cl mg/l 81 79Nitrogen, Total as N mg/l 1.4 1.2Phosphate, Ortho as P mg/l <0.1 <0.1Phosphorus , Total as P mg/l <0.1 0.1

TPH >C6-C40 ug/l <50 <50TPH >C6-C8 ug/l <10 <10TPH >C8-C10 ug/l <10 <10TPH >C16-C24 ug/l <20 <20TPH >C24-C40 ug/l <50 <50TPH >C10-C16 ug/l <20 <20Salinity mg/l 1200 1200

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Habitat Design Guidance

Refugia structure taken from the Great Crested Newt Conservation Handbook (Langton et al, 2001)

Pond margins profile and planting taken from Great Crested Newt Conservation Handbook (Langton et al, 2001)

Ditch bank profile taken from Water voles in the Uplands, (Derbyshire Wildlife Trust, 2004)

impacts on designated sites, drainage …...conservation handbook advises that semi-improved...

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