BIOGAS FACILITY i ·Courteenhall,
Report prepared for:
Agrivert Limited The Stables Radford Chipping Norton Oxfordshire OX74EB
Tel. 01608677 700 Fax. 01608677 711
Wolverhampton Science Park,Wolverhampton, WVlO 9RU Tel: 01902 824111, Fax: 01902 824112 Bf Consultant Hydrogeologists Limited email: [email protected] www: http://www.bclhydro.co.uk
Company Registratbn Number: 4043373 Registered in England &.Wales. Registered Oftee: 33 woverticrnpton Road, Connock. Bel Document Reference: B/WlF /002/08.doc
PROPOSED BIOGAS FACILITY West Lodge Farm, Courteenhall, Northamptonshire
Flood Risk Assessment
October 2008
Report Prepared by
Paul Burfitt B.Sc. M.Sc. FGS. Senior Hydrogeologist
This report has been prepared byBCl Consutant Hydrogeologists Limited with all reasonable skill, care and diligence, within the terms ofthe Contract made with the Client. The report is confidential to the Client and BCl Consultant Hydrogeologists Limited accept no responsibility to third parties to whom this report may be made known. No part of this report may be reproduced without prior written approval of BCl Consultant Hydrogeologists Limited. Where data supplied by third parties has been reproduced herein, the originators conditions regarding further reproduction ordistribution ofthat data should be sought and observed.
Technology Centre Wolverhampton Science Park,Wolverhampton, WVl 0 9RU [Jf Consultant Hydrogeologists Limited Tel:01902824111, Fax:01902 824112 email: [email protected] www: http://www.bclhydro.co.uk AGRIVERT LIMITED West Lodge Farm Biogas Facility, Courteenhall. Northamptonshire Flood Risk Assessment
CONTENTS Page Number
1 INTRODUCTION 5
1.1 Background 5
1.2 Data Sources 5
2 BASELINE DATA 7
2.1 Site Description 7
2.2 Hydrological Setting 9 2.2.1 Surface water drainage 9 2.2.2 Limits offlooding 10 2.2.3 Surface waterbodies 11
2.3 Hydrogeological Setting 12 2.3.1 Baseline description 12 2.3.2 Abstraction 12
3 THE PROPOSED DEVELOPlVIENT 13
3.1 Overview 13
3.2 Water Management Within The Proposed Development 13
4 ASSESSMENT 15
4.1 Sequential test 15 "-' 4.2 Offsite impacts 17
4.3 Climate change 19
4.4 Mitigation of impacts 19
4.5 Residual risk 19
5 SUMMARY AND CONCLUSIONS 21
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FIGURES
Figure 1: Location plan. Figure 2: Geology - Extract ofBGS Sheet 202. Figure 3: Watercourses and drainage. Figure 4: Extract of Environment Agency Flood Plain Map. Figure 5: Proposed Site layout (Drawing No. Nor-West-002 provided by Agrivert Ltd).
TABLES
Table I: Initial Risk Screening. Table 01: Flood Zones (PPS25). Table 02: Flood Risk Vulnerability (PPS25). Table 03: Flood Risk Vulnerability and Flood Zone Compatibility (PPS25).
APPENDICES
Appendix I: Figures. Appendix II: Calculation of Storm Attenuation Volumes
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1 INTRODUCTION
1.1 BACKGROUND
1.1.1 A planning application seeking permission for development of an anaerobic digestion biogas facility at West Lodge Farm, Courteenhall, Northamptonshire (the Site) has been prepared by Agrivert Limited (Agrivert).
1.1.2 The Site, which is centred upon NGR SP 751 531, currently comprises an area of arable agricultural land, adjacent to the main farm storage buildings and hard standing area at West Lodge Farm.
1.1.3 The development will cover an area of approximately 1.9 hectares (ha) to accommodate the construction and installation of a reception building, 2 storage tanks, 3 digester tanks, access roads, energy crop storage area and electricity generators. All processing activities will be carried out within the covered and sealed reception building and processing tanks.
1.1.4 In accordance with Planning Policy Statement 25: Development and Flood Risk (PPS25), a Flood Risk Assessment (FRA) is required to accompany any planning application relating to development ofarea greater than 1 ha or affecting areas at risk of flooding. BCL have been instructed by Agrivert to undertake a FRA to accompany the planning application for the Site.
1.1.5 This report summarises the findings of the FRA and details recommendations for inclusion within the development proposals to ameliorate any potential flooding risk.
1.2 DATA SOURCES
1.2.1 A program of desk and field study has been conducted in preparation of the FRA. Data sources utilised within this assessment are outlined below:
• Planning Policy Statement 25 (PPS 25): Development and Flood Risk, Communities & Local Government, 2006. • Development and Flood Risk: A Practice Guide Companion to PPS25, Communities & Local Government, 2007. • I:25,000 Explorer series sheet 207 "Newport Pagnell and Northampton South". • Environment Agency (EA) flood map information.
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• 1:50,000 published geological map sheet 202 "Towcester", Solid and Drift Edition, British Geological Survey (BGS). • Agrivert Limited (Agrivert), Site surveys and general information provided by site management • Field investigations undertaken by BeL. Water features survey and flow estimation August 2008.
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2 BASELINE DATA
2.1 SITE DESCRIPTION
2.1.1 The West Lodge Farm site is located approximately 7.5 kilometres (km) to the south ofNorthampton at Courteenhall, to the west ofthe A508 (figure 1, all figures to this report are included at appendix i). The National Grid Reference (NGR) for the centre ofthe Site is SP 751 531.
2.1.2 The Site is located upon the northern flank of an east - west oriented ridge. The land surface encompassing the Site occurs at an elevation of some 116 metres above ordnance datum (maOD). To the north the land surface reduces relatively rapidly from the ridge, to a basal elevation of some 85maOD, O.75km from the Site. To the south the land surface rises gently to a peak of some 120maOD at approximately 1km from the Site.
2.1.3 The land surface rises slightly to the west of the Site attaining a peak at 125maOD, 1.5km from the Site boundary. To the east, the land surface decreases into a minor valley within an area known locally as The Wake Knot, before rising to remain at a relatively consistent elevation of some 115maOD within the area surrounding Courteenhall House.
2.1.4 The southern boundary of the Site is defined by an east - west oriented minor road (Courteenhall Road) between the A508 and Blisworth. The predominant land use in the area encompassing the Site is arable agriculture.
2.1.5 The Site is underlain by the Blisworth Limestone of the Great Oolite Series (figure 2). The strata display a slight dip (less than 5°) to the southeast. The Blisworth Limestone is underlain by the Upper Estuarine Series, and subsequently Lower Estuarine Series of the Inferior Oolite. These units are present in outcrop within the flank of the aforementioned ridge feature to the north of the Site. Further north, the predominantly clay units, of the underlying Lower Lias form the solid strata.
2.1.6 The geological map for the locality suggests the combined oolitic limestones units will be present to approximately 5 metres below ground level (mbgl) beneath the Site and pinching out to the north. The underlying clay of the Upper Lias is thus expected to be present at an elevation ofsome I 11maOD.
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2.1.7 Both to the north and south of the Site extensive glacial deposits of Boulder Clay cover the underlying solid strata. The closest such deposit occurs approximately 1km to the south of the Site occupying the higher ground of the aforementioned east west oriented ridge and lying upon Blisworth Limestone strata.
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2.2 HYDROLOGICAL SETTING
2.2.1 Surface water drainage
2.2.1.1 The Site is located within the catchment for the River Nene. The River Nene flows to the south of Northampton city centre, eventually feeding into the River Great Ouse via the Bedford Levels.
2.2.1.2 As described above, the Site is located within an area underlain by the Blisworth Limestone of the Great Oolite Group. These strata are largely free draining and hence there is an absence of naturally occurring surface water features on the areas of raised ground in the locality. Approximately 200m to the northwest of the Site a pond has been constructed at an elevation of some 102maOD at Courteenhall West Lodge. This is located off the Blisworth Limestone, being underlain by clays of the Upper Lias (figures 2&3).
2.2.1.3 Watercourses and drainage are primarily located in areas underlain by the various clay strata in the locality (Boulder Clay or Lower Lias), reflecting the lower permeability of these units. The principle watercourse in the vicinity of the Site is located within the valley to the north. This unnamed watercourse is herein referred to as the ''Northern Watercourse". The Northern Watercourse arises to the northwest of the Site from drainage associated with the adjacent railway (NGR SP 742 536). The watercourse flows to the northeast beneath the MI, combining with a more significant watercourse north of Grange Park (NGR SP 765 555). The combined watercourse links into the River Nene to the southwest of Northampton (NGR SP 723 589).
2.2.1.4 To the east of the Site a watercourse arises within the northern section of the minor valley feature identified within the land surrounding Courteenhall Park (NGR SP 754 535). The watercourse arises within an area referred to locally as Watermill Spinney. This area is underlain by Tufa deposits (formed by precipitation ofcalcium carbonate from the watercourse) situated upon the clay solid strata of the Upper Lias. This second minor watercourse flows to the north for approximately 400m before feeding into the Northern Watercourse at NGR SP 754 540.
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2.2.1.5 The aforementioned watercourse may also receive flow from a minor drainage channel located to the southeast of the Site, adjacent to the A508. This is fed by rainfall runoff incident across the area ofBoulder Clay to the south.
2.2.1.6 The flow in the Northern Watercourse was estimated, as part of a water features survey conducted on 13th August 2008, to be 5 litres/second (l/s) as the watercourse arises from the railway drainage northwest of the Site, and 5Vs downstream at the A508 survey point (NGR SP 753 540) i.e. there had been no significant accretion in flow between the two survey locations.
2.2.1.7 Similarly, during the same survey, flow from the Watermill Spinney watercourse was estimated as less than 0.1 l/s at the point downstream of the A508 - Quinton road (NGR SP 753 536). The drainage channel to the southeast of the Site and upstream ofthe Watermill Spinney was recorded as dry at the time ofsurvey.
2.2.1.8 The existing Site comprises an arable field located adjacent to an area ofagricultural storage barns constructed on concrete hard standing. Incident rainfall across the barn and hard standing areas is collected within drainage and discharged to soakaway. The farmer advises that the area of field designated for development is free draining without the need for land drainage.
2.2.2 Limits of flooding
2.2.2.1 The indicative maximum limits of flooding, as defined by the EA, for the watercourses in the vicinity of the Site, are reproduced at figure 4. These show the extent of flooding that has a 1% (1 in 100) or greater chance of occurring each year (Zone 3 - darker blue) and a 0.1% (l in 1000) or greater chance of occurring in each year (Zone 2 -light blue).
2.2.2.2 The indicative flood plain for the Northern Watercourse, the area of flood plain closest to the Site, is designated to begin in the area upstream of the culvert beneath the Ml (some 1.5km from the Site). No flood plain is defined for the area immediately north of the Site. It is estimated that the defined limits of flooding are equivalent to a level ofsome 80maOD in the vicinity ofaforementioned culvert.
2.2.2.3 The flood plain continues along the length ofthe Northern Watercourse, downstream of the Ml, with a width of typically 2-5m, through the residential area of Grange
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Park. The defined limits of tlooding suggest a number of properties, both residential and commercial, are at risk offlooding under prevailing conditions.
2.2.3 Surface waterbodies
2.2.3.1 Two waterbodies are located within a 500m radius of the Site (figure 3). These are both located within areas underlain by Upper Lias clay strata, at Courteenhall West Lodge and Watermill Spinney.
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2.3 HYDROGEOLOGICAL SETTING
2.3.1 Baseline description
2.3.1.1 Details of the hydrogeological regime for the area encompassing the Site have been drawn from a combination ofsite observations made during the water features survey described above, examination of the geological map for the locality, geological memoirs and discussion with local landowners.
2.3.1.2 The presence of the clay of the Upper Lias beneath the Great Oolite Limestone serves to create a perched groundwater system within the limestone and create a shallow but laterally extensive aquifer unit. The presence of the Boulder Clay overlying the limestone strata to the south, will serve to direct incident rainfall to the edges of the impermeable cover where recharge can then occur (as identified within the drainage channel to the south east ofthe Site).
2.3.1.3 The pattern of drainage in the locality suggests groundwater flow within the area encompassing the Site will be split between westerly flow towards drainage associated with the railway and to the east towards the minor watercourse at Watermill Spinney. However, as the Site is located towards the feather edge of the limestone outcrop it is unlikely that the aquifer will provide a significant contribution of flow to either location, or possess a significant saturated thickness.
2.3.1.4 The proximity and elevation of the points of groundwater discharge from the limestone strata, coupled with the anticipated limited saturated thickness as described above, suggest groundwater levels beneath the Site are considered unlikely to exceed 112maOD, a standoffofsome 4m from the land surface.
2.3.2 Abstraction
2.3.2.1 Examination of the Environment Agency database of Public Water Supply Abstraction indicates there are no Source Protection Zones defined for the area encompassing the Site.
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3 THE PROPOSED DEVELOPMENT
3.1 OVERVIEW
3.1.1 The Site currently comprises an agricultural field with incident rainfall percolating relatively rapidly into the underlying geological units.
3.1.2 The proposed development includes for the construction of an anaerobic digestion facility for the processing oforganic material and production ofbiogas for electricity generation (figure 5). The development will require construction of a reception building, access roads, parking area, silage/energy crop storage area, ancillary buildings/plant and 5 digester/storage tanks. The site will occupy a total area of some 1.9ha.
3.1.3 All processing of organic material will be undertaken within sealed buildings, For this assessment the development has been split into three catchment areas: 1. roof area for the reception building and access roads/parking areas, 2. roof areas for storage and digester tanks, and 3. silage/energy crop storage area. The surface area of these equate to some O.39ha, 0.47ha, and O.23ha respectively.
3.2 WATER MANAGEMENT WITHIN THE PROPOSED DEVELOPMENT
3.2.1 Rainfall incident across the various buildings will be directed to groundwater via a series of soakaways. In the case of the digester and storage tanks it is proposed to construct soakaway as rings around the perimeter of each building. The soakaway area will also incorporate volumes for storm attenuation. This is discussed in greater detail at section 4.2.
3.2.2 Rainfall incident on the access road is to be directed via appropriately designed hydrocarbon interceptors and silt traps to one of two soakaway areas: the main soakaway area to be constructed adjacent to the Site access road from Courteenhall Road, or a secondary area located in the southwestern corner ofthe Site.
3.2.3 Rainfall incident on the silage/energy crop storage area is to be incorporated with any silage effluent, and directed to a separate lined catchment tank/pit. This will be kept separate to the soakaway system to ensure no degradation in groundwater quality in the locality. A proportion of the runoff water accumulating within the catchment pit
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will be used within the digestion process. For the excess runoff, it is recommended that an application is made to the Environment Agency (in accordance with the Nitrates Directive) to agree a suitable area of agricultural land for spreading any excess collected water.
3.2.4 Although no soakaway test has been conducted at the Site, due to the free draining nature of the underlying geology, in this instance, it is expected that the calculated storm attenuation volumes to be included within the soakaway features would exceed the dimensions specified for soakaway design that would be derived from such a test. It is thus expected that overland discharge will not be required from Site (as is the case at present for dealing with runoff from the area at present).
3.2.5 The foregoing notwithstanding, following discussion with the EA it should be expected that a soakaway test will be required at the construction phase for the site to ensure adequate design and capacity for dealing with runoff from a 1 in 100 year storm event (see section 4.2 below).
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4 ASSESSMENT
4.1 SEQUENTIAL TEST
4.1.1 An initial appraisal of flooding risk has been undertaken in accordance with Annex C ofPPS25 to establish the risk posed to the Site itself by flooding. The results of this assessment are reproduced at table 1.
Table 1. Initial Risk Screening Potential Risk Potential of Occurrence Notes (Qualitative) Flooding from Rivers No potential Site islocated outside any area deemed tobe at risk offlooding from rivers. Flooding from the Sea No potential Site islocated outside area deemed to be atrisk offloodina from sea. Flooding from Land No potential Land surrounding site is free draining. Site is raised sliohtly above surroundino. Flooding from Groundwater No potential Groundwater isestimated tooccur a minmum of 4m below the ground level atSite, hence will not impinQe on the oround surface. Flooding from Sewers No potential No sewers are present inlocality. Flooding from Reservoirs, Canals Nopotential No reservoirs, canals orother sources in and Other Artificial Sources proximity.
4.1.2 It is apparent that the initial risk screening detailed above does not highlight any areas in need of further assessment. Hence, in accordance with PPS25 (table D1 reproduced below), considerations are focussed towards any potential offsite effects.
4.] .3 Under PPS25 an assessment of appropriate activities that may be undertaken within the various defined flood risk zones is presented (table D2 below). The proposed development falls into the category "Waste treatment (except landfill and hazardous waste facilities)" and hence is deemed permissible within Zones 1 - 3a (table D.2).
4.1.4 Comparison of the Flood Risk Vulnerability to Flood Zone (table D.3) indicate the development is classified as "less vulnerable" to flooding impacts and an Exception Test will not be required in this instance. It is thus apparent that, in terms of flooding risk, the proposed development can be regarded as being appropriate at the West Lodge Farm Site, subject to satisfaction ofany issues relating to offsite impacts.
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'foible 0.1: Flood Zones (Not~: Thes~ Flood Zones refer to the probabHity of river and sea flooding. ignoring the presenc~ of defences) Zone 1 low Probability Definition This zonecomprlses land assessed .·baviog·aless than 1 in 1000 aMUalprobalMlity of river oneatboding In anyyeal (<0.1 'KJ). Appropritlte U$es All uses of land.an! appropriate III thisZQIle, fAA requJrements For. dMIopment proposals onsltescomprlslng ·ooe·hectareor;above tM 'NNtablIity to floodIr1g.fn:Kn other SOlKe5 as weII'asfrom .rlwrandseatIoodiFYJ. iRIthe ~to Increase fIooddsk elsewhere tlYough the addition of haIQ surfaces aoQ.1ne ektqfthe newdewtopmenton SlIface wateflUtl-Off,.·shouldbe incorporated Ina FRA.lhlsneed onlybe briefunless thefactoIsaboveQr otherlocal consldetatlons ~\.IlIe particular attention. see Annex Efor mlniMJmr~nts. PoIkyalms In tbls zone,~efopen and local authorities.sflcdd seeIt oppomntfes to reduce the overaltleYel of flood tlsklnthe ~ and.bejond tJvex.t9h the Ia)QJtandfor'mof the development, and the appropriate applcatlon ofsustainable drainage techniques.
'foible 0.2: Flood Risk Vulnerability classification
Less 'NInel'able • BuUngs Ulied for: shops; finandaJ, professional and otherservices; restaurants.and cafes; hotfood takeaways; offices; general indtlstfy; $torage anddstribl,Jtlon; noo-residentJatinstltutlons not lnduded In 'more Vulnerable'; andassembly anlflelsln. • Land andboIkIlnO$ usedfor agictiture andfofestry. • waste treatment (except IandftII and hazardous ;.\WSte; fac;~. • Mlneraas WOI'king and procesmg (except for sand andgravel working). • Watertfeatrnent plants. • sewage 1Jeatment pt,ants (If ·adequate pollution control IJ\NSIRS are In place).
'foible D.3u : Flood Risk Vulnerability and Flood Zone 'Compatibility"
0 Zone2 v v Exception v t/ <].I Test J5 required ~ <].I -S Zone3a Exception Test X Exception required Test ~ required ------"--- ----- 8 Zone 3b Exception Test v X X X u:: 'Functional required Floodplain'
Key: t/ De~opmentis appropriate X Development should not be permitted
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4.2 OFFSITE IMPACTS
4.2.1 It is a requirement of PPS25 that site-specific FRA's be undertaken for all sites, including those in Flood Risk Zone 1,with an area greater than one hectare, to ensure that downstream flooding problems are not exacerbated by run-off from the developed area. The key requirement relevant to the Site, as presented in Chapter 4 of "Development and Flood Risk: A Practice Guide Companion to PPPS25", is presented in extract below.
Off-site impacts For the range of annual flow rate probabilities up to and including the 1 per cent annual exceedence probability (1 in 100 years) event, including an appropriate allowance for climate change, the developed rate of run-off into a watercourse, or other receiving water body, should he no greater than the existing rate of run-off for the same event, Run-off from previously-developed sites should be compared with existing rates, not greenfield rates for the site before it was developed. Developers are however encouraged to reduce run-off rates from previously-developed sites as much as is reasonably practicahle. Volumes of run-off should also be reduced where possible using infiltration
4.2.2 As described at section 3 the proposed development has incorporated design features for the control of rainfall runoff at the Site to prevent the need for any discharge to the surface water environment in accordance with the guidance stated above.
4.2.3 It is proposed to include storm attenuation volumes within the Site drainage system for each of the catchment areas identified at section 3.1. Each of the attenuation volumes have been calculated using the methodology detailed in the following guidance: "Preliminary rainfall runoff management for developments", Technical Report W5-074NTRI1, Revision D, published by Defra / Environment Agency Flood and Coastal Defence R&D Programme, September 2005. Full details of this calculation are provided at appendix ii.
4.2.4 In accordance with the aforementioned methodology, a range in storm Return Periods of between 1 in 1, 30 and] 00 years have been utilised.
4.2.5 For the access road and reception building, the calculations suggest an attenuation volume of some 163m3 should be incorporated within the soakaway system to balance a 1 in 100 year storm event. It is recommended that sufficient capacity is included to accommodate this volume within the designated soakaway areas, either
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the main area to be constructed adjacent to the Site access road, or the smaller area located in the southwestern corner ofthe Site.
4.2.6 Similarly, to accommodate runoff from the digester and storage tanks, a total volume of some 300m3 will be required for incorporation within the designated soakaway areas. This equates to some 60m3/tank. It is proposed to incorporate the aforementioned capacity within radial soakaway areas surrounding each ofthe tanks. Assuming these are backfilled with gravel, this will leave void space for attenuation of some 10%. Hence, to provide sufficient attenuation capacity, each of the radial gravel filled soakaway areas will need to be a minimum of2.5m wide and 2m deep.
4.2.7 A second option would be to direct rainfall runoff from the various tanks into the main soakaway area. This would necessitate increasing the attenuation volume 3 within the main soakaway area by some 300m .
4.2.8 The proposed development will include provision of a lined catchment tank to accommodate runoff from within the energy crop storage area. Runoff within this area will be kept separate from the soakaway system and a proportion of water will be used within the digestion process.
4.2.9 The aforementioned calculations have been repeated to assess the likely volume of storage required within the energy crop storage area to balance runoff created during the various storm Return Periods. The calculated attenuation volume required to 3 balance a I in 100 year Return Period storm equates to some 145m .
4.2.10 It is of note that no consideration has been given to the design of pipe/channel infrastructure to convey runoff water within the site at this stage. As runoff from the roofs of the various enclosed tanks is to be treated within adjacent soakaway areas and runoff from the energy crop store is to be held within a lined catchment tank, these will not require significant additional drainage infrastructure. This leaves consideration of runoff for the Site access road and reception building roof. It is recommended that appropriate drainage is incorporated at the deign stage for the Site access roads etc to address this issue, utilising current best practice design methodologies for management ofsuch runoff.
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4.2.11 Assuming incorporation of the foregoing attenuation features, it is considered that the proposed development will have insignificant potential to cause a detrimental effect on flooding risk downstream ofthe Site.
4.3 CLIMATE CHANGE
4.3.1 The calculations for storm attenuation volumes presented above include provision for increased volumes resultant from climate change (10%). These have been calculated in accordance with the prevailing guidance (appendix ii, Preliminary Rainfall Runoff Management for Developments W5-074/AfTR/l, Rev D, Para 16 pg xvi).
4.4 MITIGATION OF IMPACTS
4.4.1 Design factors have been recommended for incorporation into the proposed development to effectively ameliorate any increased risk to flooding in the locality. The inclusion of storm attenuation volumes within the soakaway points at the Site will serve to ensure greater control of surface water runoff at the Site, whilst seeking to discharge any runoff water via infiltration in accordance with prevailing guidance.
4.5 RESIDUAL RISK
4.5.1 Flood risk to people and property can be managed but it can never be completely removed; a residual risk will remain after flood management or mitigation measures have been put in place. The runoff calculations have been designed to meet the flood management design standard of a I in 100 year storm Return Period using current calculation methods. The water control measures could be exceeded under extreme conditions such as a storm event with a Return Period of greater than I in 100 years.
4.5.2 It is therefore recommended that drainage measures be incorporated into the design of the Site to ensure any water backing up from the soakaway area(s) for the access/reception area will not impinge upon access to the Site, or the energy crop storage area. It is recommended that the soakaway areas include an overflow channel to allow discharge of excess runoff water to adjacent farmland to the northeast of the Site, during any such periods ofexcessive rainfall.
4.5.3 It is also recommended that a programme of annual assessment and maintenance be undertaken to clear excess vegetation and silt etc from the soakaway area, and to ensure the ongoing efficiency ofthe soakaway system.
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4.5.4 For the energy crop storage area it is recommended that the perimeter of the concrete pad is sealed and raised to approximately a.3m to create a failsafe system for accommodation of any extreme rainfall events as described above, that may exceed the combined capacity of the catchment tank and absorbent properties of any stored material.
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5 SUMMARY AND CONCLUSIONS
5,1.1 A Flood Risk Assessment (FRA) has been undertaken to assess proposals to develop a Biogas Facility at a site known as West Lodge Farm, Courteenhall, Northamptonshire (the Site).
5.1.2 The proposed development comprises the construction ofaccess roads, buildings and areas of hard standing within a Site of some 1.9 hectares (ha) areal extent. The Site currently comprises an agricultural field utilised for crop production.
5.1.3 The development can be subdivided into three areas; Area 1 comprises the reception building and access roads, Area 2 comprises the storage/digestion tanks, and Area 3 comprises the energy crop storage area. Areas 1&2 will discharge incident rainfall to designated soakaway area(s), whilst Area 3 will incorporate a lined catchment pit to retain combined rainfall runoffand leachate within the energy crop storage area.
5.1.4 The Site lies outside any areas designated to be at risk of flooding (Zone 1). Under guidance presented in Planning Policy Statement 25 (PPS25) the Initial Risk Appraisal suggests the development proposals will not adversely affect the risk of flooding to the Site itself. Furthermore application of the Sequential Test indicates the proposed development is appropriate for the location in terms of flooding risk, being classified as the lowest risk - "less vulnerable".
5.1.5 In consideration of potential offsite impacts, recommendations are made for the incorporation of storm attenuation capacity within the water management system to ameliorate any need for overland discharge from the Site.
5.1.6 The FRA concludes, with inclusion ofthe design factors to provide storm attenuation for runoff, the development proposals have insignificant potential to adversely affect flooding risk in the locality. It is however recommended that the energy crop storage area includes above ground containment to provide a failsafe system to accommodate any exceedance ofthe design capacity ofthe catchment tank.
5.1.7 Similarly, for the access roads and reception areas, it IS recommended that a point of overland drainage be created from the main soakaway area to the adjacent farmland to the northeast, to prevent a build up ofrunoffwater within the confines ofthe Site during extreme rainfall events (greater than a 1 in 100 year Return Period).
BfConsultant Hydrogeologists Limited Page 21 BCL Document Reference: B/WLF/002/0B.doc Bel Document Reference: B/WlF/002.doc/08
PROPOSED BIOGAS FACILITY West Lodge Farm, Courteenhall, Northamptonshire
Flood Risk Assessment
October 2008
APPENDIX I Figures
Technology Centre Wolverhompton Science Pork. Wolverhampton. WVIO 9RU ,[)f Consultant Hydrogeologists Limited Tel: 01902 824111. Fax: 01902 824112 email: [email protected] WNW:http://WNW.bclhydro.co.uk
Company Registra1bn Number: 4043373 Reois1ered in Enalond & wctes. Recslered Office: 33 wclvemcmctcn Road. Connock. Bel Document Reference: B/WlF/002.doc/08
PROPOSED BIOGAS FACILITY West Lodge Farm, Courteenhall, Northamptonshire
Flood Risk Assessment
October 2008
APPENDIX II Calculation of Storm Attenuation Volumes
Technology Centre Wolverhomplon Science Pari<, Wolverhampton, WVl 0 9RU [Jf Consultant Hydrogeologists Limited Tel:01902824111. fox: 01902824112 email: [email protected] www: http://www.bclhydro.co.uk
Company Registralbn Number: 4043373 Reostered b Enaland & Wale s. Reaistered Ottce: 33 Wotvemamolon Road. Cannod:. DEFRAJEnvironment Agency Flood and Coastal Defence R&D Programme Preliminery rainfall runoff management for developments. R&D Technical Report WS-074/A1TRl1 Rev D. SKe: West Lodge Farm Biogas Facility. NGR of site:'751 '531. Calculation ofstormattenuation volume for runofffrom reception building. A.Greenfield estimale ofpeak flow rale ol"'noll (method forsiles <200ha)
Kem Value Notes 1.Hydrological regioo (1-9[RJI Read womFigure 1.1(W5.Q!4INTRll) 2.Soiltype (1-5IS)) Freedraining salunderlain bylimestone 3.Catchmenl size(Hectares [AJ) 1.9 Fromsurvey cala. 4, Area 01ceveknment (hectares [A}) 0.10B5 Areaof reception building 5, Annual rainfall (mm[SAAR)) 611 Read iom FEHCDROM.
6, S~I runoff coeffdenllSPRj 0.1 Readworn gUldanoo (automated here) 7,Catchmenl mean arnualpeakflow O/G{OaAAJi 0.02 FOfmula (IIlessIhan 50hal ((1.0B'(50/IOO)'0,B9'(SAAR'I.17)'(SPR'1,1711150)'A 8. Meanannuapeaknowperunitarea(Vs/ha {QBARI'All 0,1 Value of0.1is calC\Jlated fa class1 soiltype.Guidance indicates 1llshlashould be usedsincethevalueistessthan1. Ba.Value ofmeanannualpeaknow usedincalculations 1.0
10.Calculation of 1yr,30yrand 100'Itpeakdischarge rateo! runoffperunitarea. 10.1 Orw/NO.85 (V&I1Ia [0",11 .1 10.2Orw/A'GC" (I/S Kem Value Notes 1.Hydrobgical regioo (1-9[RJ) t---J Read iom Figure 1.1 (W&G741NTRll) 2. Hydrobgical ra"lall,oM (M,8D.r [I)) 2Dmm,OA Read iom Fi\J1re 2 (W5.Q74INTRll) 3. Area ofdeve!ClIJmenl (hectares [AJI 0.1085 Manuafty derived 4. Proportioo ofimpervious arearequiring attenuation sta-age (c] 1.00 100% ofrunofffromreceptonbuilding 10 be discharged to soakaway 5.Greenlield fta,vraleper",>Ia-ea (Vslha [O"R"A}) 1.0 larger valuebetween 8 and9.2above 6. Estimate of catchment percerueqe impermeable area(%(PIMPj) ~ MaruaBy derIVed (seeaboe] 7.Calculation ofattenuation storage volumes perunitarea(m%a) 3 7.11 yearrewrnperiod (mhla {U. 3 8. Calculation 01basic storage volume (m \UiOI·U ·Ai) 3 8.11 yearreturn period (m {BSV1yrJ) 2 B,2 3Q ye'" relurn period (m3 [BSV3",,1I 46 3 8.3 100yearreturn period (m {BSV1co,rlJ 8 56 9. Climate change factor ICC] ~ Guidance suggests valueof 1.1i.e, 10%for increase inattenuation capacity 10,Caklulation ofFEH Rainf~llactor 10,11yearreturn period[FF,yrl R Read values ileraijvely iom Figure 11andligures 6.1,1 ·6,3.4 (W5-074/NTR/l) 10.23D yearrehrrn period IFFOOy,J 10.3100yearreturn porod[FF100;rJ t:=Jjj 10a.Calculation of [CC/FFI ratio 10a.1yearreturn period [CC/FF l~r] ., lOb.3D yearrekrrn period [CClFF"",1 1.' 1oc. 100yearreturn period [CClF FlOO;rl 8 1.2 11Calculation of stq-age volume ratio(SVRl 11.11yearreturn period [SVR1yrl 1.12 Readvalues from Figures 8.1 - 8.8 (W5-074/AJrRl1) toobtain rauos 11.230yearreturn period [SVR;,J~ll 1.12 11.3100yearreturn period [SV~oo,rl 1.24 12 Calculation of adjusled sto aqevolames (mJ [SVR*BSV]) 12.11yearreturn period [ASV,yrl 4 12,23D yearreturn period IASV""J 51 12.3100yearreturn period [ASVHCyrl [370 13.Calculation ofGrO'oYth CurveFeeler 13.11yearreturn period Calc iom tableinsetal Figure 1.2(W5-074/NTR/I) 13.230yearreturn period Usetolookupslorage ratiolor answer loq14 on Figure 9. 13.3100yearreturn period 14.Caklulation at hydlologic~ region vcemestOfage ratio[HRj 14.11 yearreturn period [HR1yr] 14.230yearreum period lHRlJ'I'll 14.3100 ,e", return period [HR,,,,,,1 15.Calculation of final estimated attenuation volume (mJ [HR*ASV]) 15.11yearreturn period [AIVoI1yr] 4 15.23D yearreturn period IAIVeI",,1 51 15,3100yearreturn period[AtVoI100yr] [370 DEFRAlEnvironment Agency Flood and Coastal Defence R&D Programme Preliminery rainfall runoffmanagement fordevelopments. R&D Technical Report W5·0741AfTRJ1 Rev D. Site: West Lodge Farm Biogas Facility. NGR of site: '751'531. Calculation ofstormattenuation volume forrunofffromaccess roads etc. A.Greenfield estimale ofpeakflowrateofrunoff(method for sijes<200ha) ~.m Value Notes 1.Hydrolo9cal reqkn(1·9(RD 5 Read from Figure 1.1(W5·074/NTRlI) 2. Soil type(1.5[SJ) I Freedrainingsoilunderlain by limestone 3. Catchmenl size(Hectares IAJ) 1.9 From survey data. 4. kfOB of development (hectares (AJ) 0.2775 Areaof newaccess roads etc 5. Annual r~nfa" (mm[SAARD 621 Read fromFEH COROM. 6.Soilrunoff cceftcient [SPRj 0.1 Readfromguidance (automated here) 7. Catchment meanannual peakdow(1/s1QaARD 0.04 Formula (ifless lI1an 50hal:(1.08'(50/1 00)'O.89'(SAAR'I.17)'(SPR'2.17))/50)'A 8. Mean annual peakRow perunitarea(VsJha IQflAJ../AJ) 0.1 Value of0.1is calculated forclass 1selltype. Guidance indicates lIIs1ha should be used since thevalue islessthan 1. Sa,Value ofmean annual peakflowusedincalculations 1.0 10.Calculation of 1yr,30yrand100yr peakdischarge rateof runoffper unitarea. 10.1 0"""A'0.85 (Vslha [0",]) ,' 10.2 O""'A'GC,, (1Is,"a [0",,11 0.4 Read GC" and GC,,,,, from Rgure1.2 (W5·0741NTRl1) 10.1 O",,'A'GC,oo(Vslha 10,,,,,,]) 8]0.5 B.Assessment ofattenuation storage volumes & sloragerate ~.m Value Notes I. Hyd1Ological re9i'" (1·9IRJ) ~ Read from Figure 1.1(W5·0741AfTR/1) 2. Hydrological rainlallzone (M,60.r [lJl 20mm,0.4 Read fromFigure 2 (W5·0741MR/1) 3.Nea ofdevelopment {hectares [AJ) 0.2775 Manualy derived 4. Proportion ofimpervious arearequiring attenuation storage(Cl) 0.75 75%ot runoffexpected 10be discharged to soakaway 5.Greenfield flow tateper unit area(lfslha{QBAR"A]) 1.0 Largervaluebetwem8 and9.2above 6,Estimate of catchment percentage impermeable area(%[PIMP)) 75.0 Manually derived (see aboe) 7. Calcuationofattenuation storage vdumes per unitarea(mJfha) 3 v~ues 7,11 yearreturnperiod(m fha \Uvoll1r}) 40 Read from Figures 7.1• 7.8(selecled using M560,r values); dosestline211s1lha, 75pimp 7.130year relurn period (m''''a IU,d'l 8. Calculation ofbasicstoragevolume (mJ{Uvct"a"AJ) 8.11 yearreturn period(m3 [BSV',yrJ) 8.230 year relurn period (m' (BSV3""D R J 8.3100yearreturnperiod(m [BSV1OO;lll ~ 9. Oimale change faclor ICCj ~ Guidance suggests valueof 1.1t.e.10%fOl' increase inattenuation capacity 10.Calculation of FEHRainfall factor 10.11 yearretumperiod(FF1~{1 R Read values iteralively from Figurei1 andfigures 6.1.1·6.3.4(W5·0741NTRI1) 10.2 30year relurn period [FF""j 10.3100 year return perrod [FF,,,,,,./ o lOa.Calculali'"of [CClFF] ralio lOa.1 yearrelum period [CCIFF..,I .1 1oe, 30yearreturnperiod[CCIFFJJvrJ 1.1 10c.l00 year return period [CC/FF,,,,,,J 8 12 11 Calculation of sloragevolumeratio(SVRI 11.11 yearreturnperiod[SVR1yrl Read values from Figures 8.1·8.8 (W5-0741NTRlI) 10 oblaln rahos 112 30year relurn porodISVR3~,1 11.3 100year return period [SVR,,,,,,J 12 Calculation of adjusted storagevolumes (m3 rSVWBSVj) 12.11 yearreturnperiod[ASV11rJ 12.230 yearreturnperiod[ASVl)~r] R 12,3100yell returnperiod[ASV100vrJ t=:.=j 13.Calculation of Growth CurveFactor 13.11yearreturnperiod Calcfrom table Inset at Figure 1.2(W5-0741NTRII) 13.230yearreturnperiod Use tolookup5101'3ge ralio foranswer 10q14on Figure9. 13.3100year relurn period 14.Calculation of hydrological reaimvolume slorageratio[HR] 14.11 yearreturnperiodiHRly,) 14.2 30yearreturn period [HRlly,] 14.3 100ye" return period [HR,,,,,,! 15,Calculation of finalestimated auenuafion volume(mJ [HR"ASV]) 15.11year relurn period \AIVol",1 15.230yearrelurn period [AIVd,~,J R 15.3100ye.. returnperiod {AtVoliO(~rl o DEFRAlEnvironment Agency RoodandCoastal Defence R&D Programme Preliminery rainfall runoffmanagement for developments. R&D Technical Report W5·0741AfTRJ1 Rev D. S~e: West Lodge Farm Biogas Facility. NGR of s~e: '751'531. Calculation of storm attenuation volume for runofffromstorage anddigester tanks. A Greenfield estimate ofpeak Row rate ofrunoff (method for.ite. <200ha) em Valu. Notos 1. Hydrolcqicel region{1-9 (RJ) 5 Readfrcn Figure 1.1(W5-Q74/NTRil) 2. S~I typO (1·5 ISII 1 Freedraining soilunderlain bylimestone 3. Catchment size(Hectare,(All 1.9 Fromsurveydata, 4. Araaofdevalopment (hectares [All 0.467 Area of digester andstorage tanks 5. Annual rainfall {mm(SAAR}) 621 Readlrcn FEH COROM. 6. Sc;Irunoff coalieioot [SPR] 0.1 Readfran guidance (automated here) 7. Catchmool moanannual paakflow (1f,[aBAAlI 0.1 Formula (IIlassthan50hal:((1.0fl'(501t00)'{)Bg'(SAAR'1.17)'(SPR'2.17))I50)'A 8, Meanannual peaktow perunitareaO/slha [QElAI/AJ) 0.1 Value 010.1 is calculated fa" class1 soiltype.Guidance indicates 1I/S1ha should beused since thevalue IS lessthan1. 8a. Valueof meal annualpeakftow usedin calculations 1.0 10.Calculation of 1yr,30yrand100yrpeakdischarge rateof runoffperunitarea. 10.1 arw/A'O.85 (I/sma (a.,,!) ·l 10.2arw/A'GC",(1l'hla (a"",]) 0.4 Rea Item Value Notes 1. Hydrological raglon (1·9[RJ) 5 Raadfrom Figura 1.1(W5-Q74/NTRill 2.Hydrological rainfaU zone (M~60,r (ZD 20mm,0.4 Read frOOl Figure 2 (W5-Q74/NTRi1) 3. Area. ofdevelopment (hectares [All 0.467 Manually derived 4,Proportion ofimpervious arearequiring attenuation storage «(1) 1.00 100%ofrunofffromtanks\0 bedischargod 10soakaway 5. Greenfield flow raie parunitaea (I/SI11a laBAR"AJI 1.0 LargEII' vafue between 8 and9.2 above 6, Estimate ofcatchment percenteqe imperrreaolearea(% [PIMP]) e.-JQQ,Q Manually derived (seeaboe) 7.cacueton of altenuation storaqe volumes per lJ1it area(mJkla) 3 7.11 yearreturn period (m/ha (Uva1)\'JJ oo Readvalues fromFigures 7.1 ~ 7.8(selected using Ms6Q,r values); ccsesuneZVsI1ha, l00pimp 7,130 yearreturn period (m3/ha (UvoIXvrlJ 420 7,1100 yearreturn period (m3/ha (U~ol,oo,orJJ B520 8. Cafculation of baSIC storage volume (m3(U~(/u -AJ) J 8,11yearreturn period (m [BSV1y,J) 3 8.230 yaarreturn penod 1m'IBSV3",,]) 196 3 8,3100yearreturn period {m [BSV100frD [3243 9. Climate cl1ange factor fCC] CL!l Guida'lce suggests valueof 1.1 r.e. 10%ferincrease inattenua.tion capacity 10.Celculauon 01 FEH Rainl~1 factor 10.11yearreturn period [FF1.11 R Readvalues lterafively tom Figura 11andfiqures 6.1.1 ·6.3.4 (W5-Q74/NTRil) 10.230yearreturn period (FF.»,orl 10.3100yeN return period (FF'OOfrl t:=riJ lOa.Calculation of (CCIfF]reuo lOa, 1yearreturnperiod [CCIFF1•rJ l lOb.30yearreturn period ICOfFJOy,1 1.1· lOc.100yearretompence {CCIFF,oO\'rl B1.2 11 Calcula~on of storage volume rato [SVRj 11.11 yearreturn p...iodISVR",J 1.12 Readvalues fromFigwes8,1- 8.8(WS.iJ74INTRl1l (0obtain ratios 11.230yearretumperiod [SVR:Il,rJ 1.12 11.3100ye~ return period (S\lR100/r] 1.24 12Cafculation of adjusted storage volumes (m)(SVRoBSVj) 0 5 12.11yea!retufI1 period {ASV1,rl 12230 yearretempetod[ASV".] 220 12.3100yearreten period [ASV'OOj,J ~J01 13.Caiculauon of Growth CurvoFactor 13.1 1yearreturn period Ceofrom lableinset'I Rgura1.2(WS-l174INrR/l) 13.230yearretumpEJlod Usetolookupstorage ratioforanswer toq14on Figure9. 13.3 100yeN return period 14.CalaJlation of hydrologica region volume s(erage ratio[HR] 14.11 yearrelurn peod [HR,.I 14.230yearreicmperiod (HR3~rl 14.3 100yearreturn period [HR,ootrl 15.Cabilationof finalestimated attenuation 'Volume (mj [HWASVD 15.1 1yearreturn period (A1VoI1.,! 15,230 yearretumperiod (AtVoI1lyrJ 15.3100yearreturn period[AtVol,ooyrJ DEFRAlEnvironment Agency Rood andCoastal Defence R&D Programme Preliminery rainfall runoff management fordevelopments. R&D Technical Report W54J74/AfTR/1 Rev D. Site: West Lodge Farm Biogas Facility. NGR ofsite:'751 '531. Calculation of storm attenuation volume forenergy cropstorearea. A.Greenfield estimate 0' peakflow rateof runoll (method 'or sites<200haj ltem Value Notes 1.Hydr"ogical reg<>o (1-9[RI) 5 Read from Figure 1.1 (W5.Q74/NTRl1) 2. SoH Iype(1-5[SD 1 Freedraining soilunderlain bylimestone 3. Calchmenl size(Heclare, [AI) 1,9 FrOOl survey data. 4, Area of developmenl (hectares [A]) 0.225 Areaofenergy cropStOf9 5,Annual rainfall (mm[SAARD 621 Read from FEH COROM. 6, Soil runoff coencent[SPR] 0,1 Read fromguidance (automated here) 7. Catchment meanannual peakflow(VS[Q8ARD 0.Q3 Formula (iflessIhan50hal:((1,08'(50/100)'0.89'(SAAR'1, 17)'(SPR'2,17))/50)'A 8. Mean annual peakflCM' perunitarea{Vshla [QBAFlA]} 0.1 Valueof0.1is calculated forclass 1 soiltype.Coldance indicates 11/shla should beusedsincethevalueis lessthan1, ea Valueofmeanannual peakftow used incalculations 1.0 10,Calculation of 1yr,30yrand100yr peakdischarge raleof runoffperunitarea. 10.1 a,,,/A'O.85(I/slha [a",]) '1 10.2 a""JNGc,o (Vs.11a [a",,]) 0,4 Read GC" andGC,,,, from Figure 1.2(W5.Q74/AITR/1) 10,1 a"R/A'GC,,,,(II,iIla[0,,,,,,1) § 0,5 B.Assessment 0' attenuation storage volumes & storage rate ltem Value Notes 1.Hydr"09ical reqon(1-9[RII 5 Read from Fiqure t.t (W5.Q74/NTR/1) 2.Hydr"09ical rainfall zone (M,60.r [Z]) 20mm,0.4 Read from Fiqure 2 (W5.Q74/AlTRl1) 3.Areaof developmenl (hecteres [A]) 0.225 Manually de-lved 4, Proportion ofimpervious aea requiring attenuation storaqe [n} 1.00 Allrunoff10 beratined within energy cropstorearea 5, Greenfield flow raleperunilarea (Vslha [o",,/AII 1.0 larger valuebetween 8 and9,2above 6. Estimate ofcatchment percenfage impermeable area(% [PIMPD 100.0 Manually derived (seeebce) 7. Calculation of attenuation storage volumes perunitarea(m%a) 3hla 7.11 yearrelurnperiod (m IU,~'yr]) 200 Read values fromFigures 7.1- 7,8(selected using M560,r values); closest line21/s11ha. 100pimp 7,130 yearreturn period {m: 8. Calculation of basicstorage volume (m3[U'IOI-u-Al) 8.1 1yearreturn period (m3IBSVlyr]) s 8.230yearreturn period (m' [BSV30" ]) 95 8.3100year relurn period 1m'[BSV,,,,,,II a 117 9, airnalechange faclor ICC] c==:11] Guidance suggests valueof 1.1i.e.10%forincrease in attenuation capacity 10.Ca~ufalion ofFEH Rainfall faclor 10.11yearreturn period [FF,yrJ R Read values ileratively from Fiqure 11 and figure,6.1.1 - 6.3.4 (W5-074/AlTRJ1) 10.2 30yearrelurn period [FF""J 10.3100yearreturn period [FF\Ootrl ~ 1Oa. Calculalion of[CClfFjratio 10a.1yearreturn pelod [CClFF1yrl ·1 10b. 30 year relurn period IOCIFF;~,] 1.1 10e. 100yearrelum period [CCIFF,oo,] S1.2 11Calculation ofstorage volume ratioISVRl 11.11yearreturn period (SVR,yrJ 1.12 Read value,from Figure, 8.1-8,8(W5.Q74/NTRl1) 10oblain ratios 11.2 30yearrelurn period [SVR",,) 1,12 11.3100yearreturn period [SVRIl(/Yrl 1.24 3 12Calculation of adjusted storage volumes (m [SVR-BSV]) 12,11yearreturn period (ASV'1fl o 12.2 30yearreturn period [ASV"",] 106 12.3100yearreturn period [ASVlOotrl § 145 13.Calculation of GrCJNl:h Curve Facta 13.11yearrelurnperiod Calcfrom tableinsel al Rgure1 ,2(WS-074/NTR/1) 13.230yearreturn period Usetolookupstorage ratioforanswer toq14onFigure 9. 13.3100yearreturn period 14.Calculation ofhydrological region volume storage ratio[HRJ 14.11yearreturn period (HR",I 14.230yearrelurn period [HR"",] 14.3100yearreturn period [HRtOotrl 15,Calculation offnal esfimated allenuation volume (m'IHR'ASV]) 15,11yearrefurn period IAlVol",] o 15.2 30yearrelurn period [AtV"",J 106 15.3100yearreturn period IAl:VoIlOCttrl § 145 Courteenhall Anaerobic Digestion (AD) Facility Local Air Quality Assessment 402.2367.00001 August 2008 Agrivert Limited i 402.2367.00001 Local Air Quality Assessment – Proposed Biogas Facility August 2008 CONTENTS 1.0 INTRODUCTION...... 1 1.1 Context ...... 1 1.2 Scope...... 1 1.3 Structure of Report ...... 2 2.0 REGULATIONS AND GUIDANCE ...... 3 2.1 UK / European Air Quality Standards and Regulations ...... 3 2.2 Odour Regulation and Guidance ...... 5 2.3 Local Planning Policy ...... 7 3.0 APPROACH...... 8 3.1 Odour...... 8 3.2 Combustion Products - Point sources (Gas engines) ...... 9 4.0 BASELINE AIR QUALITY AND SITE SETTING...... 10 4.1 Background Air Quality ...... 10 4.2 Topography...... 12 4.3 Meteorology ...... 12 4.4 Sensitive Receptor Locations ...... 13 5.0 ODOUR ASSESSMENT ...... 15 5.1 Identification of Odour Sources...... 15 5.2 Assessment of Impacts ...... 16 5.3 Residual Significant Impacts...... 18 6.0 COMBUSTION PRODUCTS - POINT SOURCES ...... 19 6.1 Proposed development – Point Sources...... 19 6.2 Assessment of Impacts ...... 19 6.3 Residual Significant Impacts...... 25 7.0 CONCLUSIONS...... 26 7.1 Approach...... 26 7.2 Results ...... 26 TABLES Table 1: Air Quality Standards and Benchmarks (EALs) ...... 5 Table 2: Ambient Air Quality...... 10 Table 3: SNDC Real Time Monitoring Data...... 11 Table 4: SNDC Passive Monitoring Data ...... 11 Table 5: Discrete Receptor Locations...... 14 Table 6: Biofilter Odour Emission Calculations (per unit) ...... 17 Table 7: Energy Crop Silage Emission Calculations...... 17 Table 8: Odour Impact at Receptor Locations ...... 18 Table 9: Point Sources and Emissions...... 19 Table 10: Engine Pollutant Emissions Parameters ...... 20 Table 11: Predicted Long Term Nitrogen Dioxide Impacts ...... 21 Table 12: Predicted Short Term Nitrogen Dioxide Impacts...... 22 Table 13: Predicted Long Term Sulphur Dioxide Impacts ...... 23 Table 14: Predicted Long Term Hydrogen Chloride Impacts...... 24 Table 15: Predicted Long Term Benzo[a][Pyrene Impacts...... 25 SLR Agrivert Limited ii 402.2367.00001 Local Air Quality Assessment – Proposed Biogas Facility August 2008 FIGURES Figure 1: Windrose For Bedford Observation Station (1999-2003) ...... 13 APPENDICES Appendix A Detailed Dispersion Modelling Checklist Appendix B Detailed Dispersion Modelling Inputs DRAWINGS Drawing AQ1: Site Location Plan Drawing AQ2: Odour Impact Assessment Drawing AQ3: Short-term Nitrogen Dioxide Impacts Drawing AQ4: Predicted Long-term Nitrogen Dioxide Impacts SLR Agrivert Limited: Courteenhall AD Facility 1 402.2367.00001 Local Air Quality Assessment August 2008 1.0 INTRODUCTION 1.1 Context SLR Consulting have been appointed by Agrivert Ltd (Agrivert) to undertake an air quality assessment for a proposed anaerobic digestion (AD) facility located at West Lodge Farm, Courteenhall, Northamptonshire. The location of the application site is shown in Drawing AQ1. The primary objective of this air quality assessment is therefore to determine whether the proposed development will give rise to significant air quality impacts. This assessment quantifies and assesses the resultant impacts from the proposed development in terms of local air quality using Environment Agency and DEFRA approved techniques and then clarifies the significance of these impacts against published standards. The report describes the assessment methodology, the baseline conditions currently existing at the application site and surroundings, the likely significant environmental impacts, the designed-in mitigation measures to prevent adverse impacts and the likely residual impacts. 1.2 Scope The scope of the assessment has been determined in the following way: • through pre-application discussions between Agrivert and representatives of the Northampton County Councils (NCC) planning department (who provided previous air quality assessments for proposed AD facilities); • review of air quality data for the area surrounding the site, including data from the National Air Quality Information Archive (NAQIA), and that relating to South Northamptonshire’s District Council’s (SNDC)s Review and Assessment of air quality; • a desk study to confirm the location of nearby areas that may be sensitive to changes in local air quality; • review of information relating to construction and operational processes and traffic flow data; and • reference to NCC’s and SNDC’s relevant planning policies. 1.2.1 Identification of potentially significant emissions The following potentially significant emissions associated with the proposed AD development have been identified: • odours arising from handling and processing of waste materials and the potential to cause annoyance in the locality of the development; and • combustion products from point sources (i.e. gas engines) and the potential to affect local pollutant concentrations. 1.2.2 Identification of Insignificant emissions The following potential emissions associated with the development have been classified as insignificant, and therefore not assessed further are; • dust arising during construction and the handling and processing during the process; SLR Agrivert Limited: Courteenhall AD Facility 2 402.2367.00001 Local Air Quality Assessment August 2008 • bioaerosols released from waste treatment processes; and • exhaust emissions from vehicles associated with the site during construction and operation. The potential emissions of dust and bioaerosols are considered insignificant due to the small scale of construction activities, the enclosure and abatement of operational sources, and the distance to sensitive receptors. Given that all reception building air is extracted through a biofilter prior to release to atmosphere this is not considered a potential source of dust or bioaerosols (studies of enclosed composting sites have shown biofilters treating the exhaust air to typically remove more than 90% of incoming bioaerosols1). The only operational activity undertaken outside relates to the silage clamp (the majority of which would be covered), however this is a typical agricultural activity. Emissions from traffic are considered insignificant given the low volume of traffic flows associated with the development. The maximum number of vehicle movements associated with the site would be approximately 60 vehicle movements per day. This increase of HGV traffic movements on the local road network is well below the criteria used to indicate the requirement for an air quality assessment of 200 HDV movements per day2 1.3 Structure of Report The remainder of the report is structured as follows: • Section 2 provides a summary of the legislation and guidelines relevant to the proposed activities at the site; • Section 3 details the methodology applied in undertaking the assessment; • Section 4 provides a description of the surrounding environment, including the identification of potentially sensitive receptors and a description of local climate and air quality conditions; • Section 5 details the assessment of odour from the proposed facility; • Section 6 details the assessment of combustion products from point sources at the proposed facility; and • Section 7 summarise the findings of the assessment. Supporting information is provided in the Appendices. 1 Sanchez-Monedero, M.A et al. 2003. Biofiltration at composting facilities: effectiveness for bioaerosol control. Environ Sci Technol. 2003. 2 Design Manual for Roads and Bridges, Volume 11, Section 3, Part 1, HA202/07 – Ari Quality. Highways Agency May 2007. SLR Agrivert Limited: Courteenhall AD Facility 3 402.2367.00001 Local Air Quality Assessment August 2008 2.0 REGULATIONS AND GUIDANCE This section provides a summary of the primary regulatory controls, planning policy and other relevant guidance to enable the assessment approaches to be viewed in context. 2.1 UK / European Air Quality Standards and Regulations 2.1.1 UK Air Quality Strategy (UKAQS) The Government's policy on air quality within the UK is set out in the Air Quality Strategy for England, Scotland, Wales and Northern Ireland (UKAQS) most recently updated in July 20073. The UKAQS sets out a framework for reducing hazards to health from air pollution and ensuring that international commitments are met in the UK. The UKAQS sets standards and objectives for ten pollutants. Standards are the concentrations of pollutants in the atmosphere which can broadly be taken to achieve a certain level of environmental quality. The standards are based on the assessment of the effects on human health (including sensitive sub groups) or ecosystems. In general, these are concentration limits, above which sensitive members of the public (e.g. children, the elderly and those of ill health) might experience adverse health effects. Objectives are policy targets often expressed as maximum concentrations not to be exceeded either without exception or with a limited number of exceedences within a specified timescale. For some pollutants, there is both a long-term (e.g. annual mean) standard and a short-term (e.g. one hour mean) standard. These periods reflect the varying impacts on health of differing exposures to pollutants. Long-term standards are generally lower than short-term standards owing to the chronic health effects associated with exposure to low concentrations of pollutants for longer periods of time. The UKAQS standards have been set taking into account the limit values (objectives) contained in the European Air Quality Framework Directive (Directive 96/62/EC) and the first, second, third and fourth Air Quality Daughter Directives (1999/30/EC, 2000/69/EC, 2002/3/EC and 2004/107/EC) for the protection of health and ecosystems. These standards are as described in the Air Quality Standards Regulations 2007. These standards have been used in the assessment where relevant. 2.1.2 Local Air Quality Management (LAQM) Part IV of the Environment Act 1995 requires local authorities to periodically review and assess the quality of air within their administrative area. The reviews have to consider the present and future air quality and whether any air quality objectives prescribed in regulations are being achieved or are likely to be achieved in the future. Where any of the prescribed air quality objectives are not likely to be achieved the authority concerned must designate an Air Quality Management Area (AQMA). For each AQMA the local authority has a duty to draw up an Air Quality Action Plan (AQAP) setting out the measures the authority intends to introduce to deliver improvements in local air quality in pursuit of the air quality objectives. Local authorities are not statutorily obliged to meet the objectives, but they must show that they are working towards them. 3 The Air Quality Strategy for England, Scotland, Wales and Northern Ireland - Defra - July 2007. SLR Agrivert Limited: Courteenhall AD Facility 4 402.2367.00001 Local Air Quality Assessment August 2008 DEFRA has published technical guidance for use by local authorities in their review and assessment work4. This guidance, referred to in this report as LAQM.TG(03), has been used where appropriate in the assessment presented here. DEFRA has also recently published LAQM (08) as a consultation draft which proposes a number of changes to the core guidance documents for use by persons involved in LAQM, or considering the impacts of a development with the potential to impact on air quality. However the present guidance LAQM.TG (03) has been used where appropriate in the assessment presented here. 2.1.3 Environment Agency Guidance – EPR H1 The Environmental Permitting Regulations (EPR) Horizontal Guidance Note for Environmental Risk Assessment5 (H1) provides supplementary information, relevant to all sectors, to assist Applicants in responding to the requirements described in the Environmental Permitting Regulations (2008). This document can be used to support an Environmental Assessment of the overall impact of the emissions resulting from the installation to confirm that the emissions are acceptable (i.e. do not cause significant pollution). The H1 guidance provides the assessor with a screening methodology and Environmental Assessment Levels (EAL’s) for each pollutant against which impact may be assessed. Emissions to air are considered to be insignificant if: • Maximum Process Contribution (long term) ≥ 1% of the EAL; or • Maximum Process Contribution (short term) ≥ 10% EAL. If impacts are defined as being insignificant, no further assessment is required; where they are not classified as insignificant, further assessment is required where background concentrations are considered to calculate the Predicted Environmental Concentration (PEC), i.e. the PC plus background. Emissions to air are considered to be significant with the need for detailed modelling as follows: • (Maximum PC (long term) + background concentration) ≥ 70% of the EAL; or • (Maximum PC (short term) + 0.2 * background concentration) ≥ 20% EAL. Although this report is intended to support a planning application, the EPR H1 guidance represents the most appropriate source of technical guidance for modelling point source emissions. 2.1.4 Benchmarks to be used in the Assessment Table 1 below presents a summary of the air quality benchmarks (or Environmental Assessment levels – EALs) to be used in the assessment of traffic and point source emissions. Details on odour, dust and bioaerosols are provided in their respective topic sections. 4 Department for Environment, Food and Rural Affairs (DEFRA): Part IV The Environment Act 1995 Local Air Quality Management Review and Assessment Technical Guidance LAQM.TG(03) (Feb 2003). 5 Environment Agency, EPR H1 Environmental Risk Assessment, (2008) SLR Agrivert Limited: Courteenhall AD Facility 5 402.2367.00001 Local Air Quality Assessment August 2008 Table 1: Air Quality Standards and Benchmarks (EALs) Pollutant Concentration Measured as Reference 3 1-hour mean not to be exceeded more than 18 Nitrogen dioxide 200 µg/m times per year (99.79%ile of hourly averages) AQS (NO2) 40 µg/m3 Annual mean Carbon monoxide 10 mg/m3 Maximum daily running 8 hour mean AQS (CO) 1 hour mean not to be exceeded more than 24 350 µg/m3 times per year (99.73 %ile of hourly averages) Sulphur dioxide AQS 24 hour mean not to be exceeded more than 3 (SO ) 125 µg/m3 2 times per year (99.18 %ile of hourly averages) 50 µg/m3 Annual mean EPR H1 24-hour mean not to be exceeded more than Particulate matter 50 µg/m3 35 times per year (90.4 %ile of hourly (PM10) averages) AQS (gravimetric) 40 µg/m3 Annual mean PAHs 0.25 ng/m3 Annual mean AQS 800µg/m3 Peak hourly mean Hydrogen Chloride EPR H1 20µg/m3 Annual Mean 2.2 Odour Regulation and Guidance 2.2.1 Planning Policy and General Nuisance Legislation The main legislation that relates to the control of odour is concerned with statutory nuisance, this is contained within Part III of the Environmental Protection Act (EPA) 1990 (as amended by the Noise and Statutory Nuisance Act 1993) and allows local authorities and individuals to take action to prevent a statutory nuisance. Section 79 of the EPA defines, amongst other things, smoke, fumes, dust and smells emitted from industrial, trade or business premises so as to be prejudicial to health or a nuisance, as a potential statutory nuisance. Planning Policy Statement 236 (PPS23) Planning and Pollution Control and Annex 1 Pollution Control and Air and Water Quality provides a list of matters to be considered in determining planning applications. Under PPS23 any potential air pollutant, dust and odour releases that could affect amenity are considered to be a material planning consideration. 2.2.2 Odour - Regulatory Standards and Guidelines Currently, in the UK there are no statutory standards for assessing odour nuisance. On this basis, odour impact criteria are typically based upon guideline documents and case law. Where a site falls under the Environmental Permitting Regulations as a Part I or Part II process, the site will be regulated to ensure it does not result in unacceptable levels of offsite odour impact during normal operation. This is the case for the proposed development. 6 Office of the Deputy Prime Minister: Planning Policy Statement 23: Planning and Pollution Control (Oct 2004). SLR Agrivert Limited: Courteenhall AD Facility 6 402.2367.00001 Local Air Quality Assessment August 2008 2.2.3 UK Guidance The Environment Agency has published a number of guidance and research documents relating to odour assessment. These are typically aimed at processes falling under the Pollution Prevention and Control Act (1999), now EPR. These include the draft Horizontal Guidance Notes H47 Parts 1 and 2, which were released for consultation in 2002. Consultation responses have yet to be published at the time of writing and it is likely to be re- issued, hence this document must be used to inform the reader of principles associated with odour, rather than representing a regulatory document. The draft IPPC H4 Guidance proposes installation-specific exposure criteria (benchmarks) on the basis that not all odours are equally offensive, and not all receptors are equally sensitive. The conditions of a Permit will balance these installation-specific exposure criteria against what is realistically achievable in accordance with the concept of Best Available Techniques (BAT). 3 The draft H4 Guidance proposes indicative criteria of between C98, 1 hour 1.5 ouE/m and C98, 1 3 hour 6.0 ouE/m as a starting point before adjustments for local factors are made, dependent upon the relative offensiveness of the source (for an explanation of conceptual basis for odour assessment and an explanation of these units refer to the methodology (Section 3.1.1). 2.2.4 UK Case-law / Common Practice The most frequently referenced case law in the UK in relation to odour assessment is that of the Newbiggin-by-the-Sea Inquiry8, defended by Northumbrian Water Limited. As a result of this case, and in the absence of any definitive Environment Agency guidance, an impact 3 criterion of C98, 1 hour 5.0 ouE/m has been frequently applied and accepted for both planning and permitting purposes in the UK, as being sufficient to prevent unacceptable odour impacts for a number of industry sectors including waste handling operations. 2.2.5 UK Water Industry Research The other source of research into odour impacts in the UK has been the wastewater industry, which given the nature of materials processed and the open nature of treatment processes is considered to be analogous to waste management operations conducted at Courteenhall. The most in-depth study published study in the UK of the correlation between of modelled odour impacts and human response (dose-effect) was published by UK Water industry Research (UKWIR) in 20019. This was based on a review of the correlation between reported odour complaints and modelled odour impacts in relation to 9 wastewater treatment works in the UK with ongoing odour complaints. The findings of this research indicated the following: 3 • At modelled exposures of below C98, 1-hour 5ouE/m , complaints are relatively rare, at only 3% of the total registered; 7 Environment Agency, 2002: Technical Guidance Note IPPC H4. Integrated Pollution Prevention and Control, Horizontal Guidance for Odour. Part 1 – Regulation and Permitting. October 2002. 8 Department of the Environment, Northern Reg. Office, Town and Country Planning Act – Section 78, Appeal by Northumbrian Water Ltd: Land adjacent to Sipal Burn, Newbiggin-by-the-Sea, Northumberland, planning reference APP/F2930/A/92 206240, 1993. 9 Odour Control in Wastewater Treatment – A Technical Reference Document. Ref 01/WW/13/3 – UKWIR, 2001. SLR Agrivert Limited: Courteenhall AD Facility 7 402.2367.00001 Local Air Quality Assessment August 2008 3 3 • at modelled exposures between C98, 1-hour 5ouE/m and C98, 1-hour 10ouE/m , a significant proportion of total registered complaints occur; 38% of the total; • the majority of complaints occur in areas of modelled exposure greater than C98, 1-hour 3 10ouE/m ; 59% of the total 2.3 Local Planning Policy 2.3.1 Northamptonshire County Council NCC Waste Local Plan The main aim of the NCC Waste Local Plan is to encourage increased waste treatment capacity for the county and reduce the reliance on landfill. One of the proposals for the Plan is to support new technologies to manage the waste. In terms of environmental impact, the Local Plan takes into account that any new development will have some degree of environmental impact, but that any impacts would need to be minimised. Policies that are included within the Local Plan that relate to the environmental impacts on the aerial environment are as follows: • Policy 8…proposals should minimise the transportation of waste associated with the proposal…; • Policy 10…proposals will not be permitted where they would be likely to result in harm to a statutorily protected species or habitat; and • Policy 15…where relevant proposals should mitigate, attenuate and control any…air quality [or] odours…associated with the planned development. The Local Plan states that in relation to air quality, providing that air re-circulation and exhaust equipment are appropriately designed and regularly maintained, that emissions are unlikely to present significant environmental problems. Processes such as anaerobic digestion, as stated in the Local Plan, incorporate odour control systems and would only cause problems if the units are opened for maintenance works. 2.3.2 South Northamptonshire District Council SNDC Local Plan, 1997. The Local Plan for SNDC was adopted in October 1997 and, together with the Structure Plan, forms the Development Plan for the area. One of the primary, general policies the Local Plan states in relation to when planning applications will be allowed is the condition that any development ‘is neither of a hazardous nature nor likely to cause problems of pollution, noise, vibration, smell, smoke, discharge or fumes’. SLR Agrivert Limited: Courteenhall AD Facility 8 402.2367.00001 Local Air Quality Assessment August 2008 3.0 APPROACH The detailed assessment of potential impacts has been undertaken utilising atmospheric dispersion modelling techniques (see Appendix B for overview). The actual assessment approach is dependent on the particular pollutant as detailed in the following sections. 3.1 Odour The odour impact assessment has used atmospheric dispersion modelling. In particular this involves estimating the potential magnitude of odour emissions from sources at the site, modelling the dispersion of odour releases in the atmosphere on the basis of meteorological data, and determining the frequency and concentration of odour at locations in the surrounding environment, particularly at local receptors (e.g. residential locations). The following sections explain in further detail the methodology employed, beginning with a description of the conceptual basis for odour assessment. 3.1.1 Conceptual Basis for Odour Assessment The assessment of an odour impact may be undertaken with two differing approaches, by the use of indicator determinands, or total odour. Where an emission is dominated by one particular odorous gas, the use of an indicator determinand may allow simple validation of an assessment through monitoring at source and receptor. For example, hydrogen sulphide in the case of emissions from sewage treatment works. However, more commonly an odour is the result of a complex mixture of chemicals. On this basis, a more appropriate approach in the case of this complex gas mixture is that of total odour. Odour assessments are undertaken using the concept of the European Odour Unit 10 (ouE), as defined in BS EN 13725 . This approach allows impact assessment of any odorous gas as it is independent of chemical constituents and centres instead on multiples of the detection threshold (i.e. the physiological response of a human) of the gas in question. As the odour unit is a Standard Unit in the same way as gram or milligram, the notation used in odour assessment follows the conventions of any mass emission unit as follows: 3 • concentration: ouE/m • emission: ouE/s 2 • specific emission (emission per unit area): ouE/m /s Like air quality standards for individual pollutants, exposure to odour is given in terms of a percentile of averages over the course of a year. This prevents results being skewed by infrequent meteorological conditions. The exposure criteria most accepted in the UK at th present is given in terms of (concentration) European Odour Units as a 98 percentile (C98) of hourly averages. This allows 2% of the year when the impact may be above the limit 3 criterion (175 hours). The notation for impact is therefore C98, 1 hour X ouE/m . 10 BS EN 13725:2003 Air Quality – Determination of Odour Concentration by Dynamic Olfactometry SLR Agrivert Limited: Courteenhall AD Facility 9 402.2367.00001 Local Air Quality Assessment August 2008 3.1.2 Impact Criterion to be used in the Assessment The objective of this part of the assessment is to determine the potential extent to which annoyance could reasonably be expected to occur as a result of emissions of odour from the site. The benchmark values proposed in the draft H4 Agency Guidance document are unlikely to be adopted. This, in conjunction with a lack of explicit guidelines in finalised regulatory and guidance documentation for an impact criterion, lead us to consider that the most 3 appropriate impact criterion to use is C98, 1 hour 5.0 ouE/m . This would follow an approach most commonly applied and accepted in the UK to date. However, given that the site will be regulated by the Environment Agency under the 3 Environmental Permitting regime, a C98, 1 hour 3.0 ouE/m has also been investigated. This is considered appropriate given the nature of the odours released from the site i.e. biofilter and silage which would fall within the ‘medium relative offensiveness’ category defined in Appendix 6 of the draft H4 guidance. 3.2 Combustion Products - Point sources (Gas engines) Horizontal Guidance Note EPR H1 presents a stages approach for the assessment of point source emissions. This approach ‘screens’ out pollutants that present an insignificant risk of impact (‘Tier 1’). Those pollutants that cannot be screened out as having an insignificant risk of impact progress onto a more detailed assessment such as an advanced dispersion modelling exercise (‘Tier 2’). Due to the proximity of receptors surrounding the Application site it is considered suitable to assess all likely combustion products using an advanced dispersion model. The predicted ground level impacts have been compared to the H1 criteria to assess significance. Where the predicted Process Contribution (PC) is not classified as ‘insignificant’, consideration has been given to the background concentration of the relevant pollutant. SLR Agrivert Limited: Courteenhall AD Facility 10 402.2367.00001 Local Air Quality Assessment August 2008 4.0 BASELINE AIR QUALITY AND SITE SETTING 4.1 Background Air Quality 4.1.1 Predicted Concentrations Predicted background concentrations for Air Quality Strategy pollutants have been calculated from the National Air Quality Archive11 UK Background Air Pollution Maps. The 1 km grid resolution maps provide 2004 background annual mean pollutant concentrations from which future concentrations are predicted by application of conversion factors detailed in LAQM.TG(03). In respect to background concentrations, at some point during 2008 / 2009 specific background maps for each 1x1km grid square will become available as described in the draft LAQM TG(08). These are unlikely to be significantly different for rural areas and at the time of writing these maps are not available. As such, correction factors provided in LAQM TG(03) have continued to be used. As the proposed development lies across two 1km x 1km grid squares, the estimated annual mean background concentrations have been taken from the grid square with the highest concentrations (GR 475500, 253500) and are shown in Table 2 below. Table 2: Ambient Air Quality 2008 2009 2010 Pollutant Concentration Concentration Concentration µg/m3 µg/m3 µg/m3 Nitrogen dioxide (NO2) 18.69 18.15 17.10 Carbon monoxide (CO) 174 163 155 (a) Sulphur dioxide (SO2) 2.12 (2005 data) 2.12 (2005 data) 2.12 (2005 data) Particulate matter (PM10) 20.17 19.82 19.20 Benzo-a-pyrene PAHs(b) 0.00014 0.00014 0.00014 Hydrogen Chloride(c) 0.47 0.47 0.47 Notes: (a) No method for calculating concentrations in years beyond 2005 is published. (b) Stoke Ferry monitoring site concentration for 2006. (c) Peak annual mean from Nitric Acid Monitoring Network (Site: Rothamsted) 1999 – 2006. The estimated annual mean background concentrations for 2009 have been used in the assessment of the first full year of operation of the proposed development. In general air pollution concentrations reduce (i.e. air quality improves) with time due to predicted reductions in vehicle pollutant emissions. Assessment of 2009 rather than a later year therefore represents the ‘worst case’ year in terms of background levels of air pollutants. 4.1.2 Local Authority Review and Assessment SNDC have declared one Air Quality Management Area as a result of elevated Nitrogen dioxide levels relating to traffic emissions in the town of Towcester. The AQMA, declared in 2005 as a result of the Progress Report, is approximately 7km southwest of the Proposed Facility. 11 www.airquality.co.uk SLR Agrivert Limited: Courteenhall AD Facility 11 402.2367.00001 Local Air Quality Assessment August 2008 Air Quality Review and Assessments undertaken since the declaration of the Towcester AQMA have concluded there is no significant risk of exceedences of any of the remaining AQS pollutants within the district. Nitrogen dioxide concentrations are continually monitored within the AQMA and across the district where residential areas are in close proximity to busy road networks such as the M1. SNDC Air Quality Monitoring Data SNDC monitor Nitrogen dioxide concentrations using a real time monitor for monitoring within the AQMA and passive diffusion tubes located across the district. Real Time Monitoring Data SNDC operate a chemiluminescent real time monitor for monitoring Nitrogen dioxide concentrations within the Towcester AQMA. The monitor, located outside Towcester Town Hall (grid reference SP693486) has been in operation since 2005, due to poor data capture during 2005, results are only available for 2006 and 2007, as shown in Table 3 below. Table 3: SNDC Real Time Monitoring Data Year Annual Average (ug/m3) Average Data Capture (%) Analyser data 2006 37.4 N/A* Analyser data 2007 37.2 98.5 * Data capture from 2006 was not available The annual mean concentrations of Nitrogen dioxide within the AQMA were recorded to be marginally below the annual mean objective of 40ug/m3. The short term objective (18 exceedences of 200ug/m3 per year) was not exceeded during 2006 and 200712. Given that the real time monitor is located within an urban area and in excess of 5km from the application site, the results are not considered to be representative of Nitrogen dioxide levels in the locality of the proposed Facility. Passive Monitoring Data Nitrogen dioxide is monitored by SNDC using passive diffusion tubes at 32 locations across the district. The locations have been chosen based upon the potential for traffic related issues that may cause elevated levels of the pollutant. Diffusion tube monitoring locations within 2km of the Application Site are shown below in Table 4 for the years 2006 and 2007. Table 4: SNDC Passive Monitoring Data Distance to 2006a Annual 2007b Annual Diffusion Tube Location Classification Application Average Average Site (ug/m3) (ug/m3) Roade; 40/40a Stradford Road Roadside 1.9km 25.13 21.86 Roade; 16 London Road Roadside 1.4km 34.97 31.40 Roade; 1 London Road Roadside 1.5km 29.03 27.76 a) Annual 2006 concentrations have been bias adjusted using bias adjustment factor 0.906 b) Annual 2007 concentrations have been bias adjusted using bias adjustment factor 0.864 12 South Northamptonshire Council, Environment Division. Air Quality Progress Report May 2008. SLR Agrivert Limited: Courteenhall AD Facility 12 402.2367.00001 Local Air Quality Assessment August 2008 Given that these diffusion tube locations are at roadside locations and in close proximity to the M1 motorway, and the rural nature of the application site, concentrations in the locality of the development will be lower. 4.1.3 Background Odour It is not possible to quantitatively measure background odour concentrations because of the low concentrations and large uncertainties in the results. Odour is therefore not routinely monitored at the site and there have been no detailed quantitative odour impact studies for the site carried out in the past. The land surrounding the application site is predominantly agricultural; as such background odours would be typical of rural locations. These would typically include occasional odours due to agricultural practises undertaken in the local area. 4.2 Topography The presence of elevated terrain can significantly affect the dispersion of pollutants and the resulting ground level concentration in a number of ways. Elevated terrain reduces the distance between the plume centre line and the ground level, thereby increasing ground level concentrations. Elevated terrain can also increase turbulence and, hence, plume mixing with the effect of increasing concentrations near to a source and reducing concentrations further away. The topography of the local area is relatively flat, with ground levels reducing slightly to the north. Within 500m of the application site ground levels reduce by 25m to the north and rise by approximately 6m to the south. To the west and east directions ground levels remain relatively flat, varying by between 3m and 4m. Topography has been incorporated into the detailed dispersion models for both combustion point sources and odour impact assessment. 4.3 Meteorology In the UK, detailed point source (odour and air pollutants) models require 3-5 years consecutive meteorological data for one station in accordance with Environment Agency Air Quality Modelling and Assessment Unit13 (AQMAU) requirements. Following consultation with the meteorological data provider, it was concluded that Bedford Observation Station, located approximately 30km to the east of the development site, would provide the most representative data set for purposes of this assessment. A 5 year data set for this station, covering the period 1999 – 2003 has been used for this assessment. Information on wind direction frequency, wind speed, frequency of stability conditions and mixing height were obtained for the Observation Station. 13 Environment Agency Air Quality Modelling and Assessment Unit (AQMAU). Online resource, available at http://www.environment-agency.gov.uk SLR Agrivert Limited: Courteenhall AD Facility 13 402.2367.00001 Local Air Quality Assessment August 2008 A windrose for the Bedford Observation Station for the years 1999-2003, providing the frequency of wind speed and direction, is presented in Figure 1. Windroses for individual years are presented in Appendix B. Figure 1: Windrose For Bedford Observation Station (1999-2003) 10% 8% 10 + m/s 6% 8 - 10 m/s 4% 6 - 8 m/s 2% 4 - 6 m/s 0% 3 - 4 m/s 2 - 3 m/s 0.5 - 2 m/s <0.5m/s The predominant wind direction is from the south south-west and southwest, producing a combined frequency of 24.8%. Winds from the north and eastern sectors are infrequent. Calm conditions (wind speeds less than 0.5 m/s) occur for approximately 2.2% of the period. 4.4 Sensitive Receptor Locations For the purposes of this air quality assessment the term 'sensitive receptors' includes any persons, locations or ecosystems that may be susceptible to changes as a consequence of the proposed development. According to the Local Air Quality Management Technical Guidance (LAQM.TG(03)), air quality standards should apply to all locations where members of the public may be reasonably likely to be exposed to air pollution for the duration of the relevant objective. Thus short term standards such as the 1 hour standard for NO2 should apply to footpaths at site boundaries and other areas which may be frequented by the public even for a short period of time. Longer term standards such as the 24 hour for PM10, or annual means, should apply at houses and other locations which the public can be expected to occupy on a continuous basis. These standards do not apply to exposure at the workplace. There are no areas in the immediate vicinity (5km radius) of the Application site that have been designated for nature conservation value that warrant specific consideration of air quality impacts. A number of discrete sensitive receptors have been selected for presentation of the air quality impacts in the surrounding area. These include representative residential properties and recreational areas (such as footpaths) in proximity to the application site. The location of the sensitive receptors considered can be seen in Drawing AQ2 and below in Table 5. SLR Agrivert Limited: Courteenhall AD Facility 14 402.2367.00001 Local Air Quality Assessment August 2008 Table 5: Discrete Receptor Locations Exposure National Grid Reference Receptor Receptor Type X Y West Lodge Farm Agricultural Short- R1 474980.7 253137.1 Building Building term/transient Courteenhall West R2 Residential Long-term 474893.7 253245.4 Lodge R3 West Lodge Cottages Residential Long-term 475264.4 253342.7 R4 The Lodge Residential Long-term 475345.5 253033.6 R5 Bridge Cottage Residential Long-term 474761.4 253051.4 Woodleys Farm (day R6 Residential Long-term 475320.3 252862.4 nursery) R7 Gamekeepers Cottage Residential Long-term 475717.3 253034.3 R8 Thorpewood Farm Residential Long-term 474363.1 252822.1 R9 Roade (north) Residential Long-term 475242.1 252105.9 R10 Hyde Farm Residential Long-term 474695.8 251786.9 R11 Blisworth Lodge Farm Residential Long-term 473521.4 253465.9 R12 Manor Farm Residential Long-term 474605.1 254423.8 R13 Grange Park Residential Long-term 476455.1 254437.3 West Lodge Farm Agricultural Short- R14 474953.5 253091.5 Building Building term/transient In addition to these discrete receptors, addition receptors were located along the nearest area of public access i.e. road and footpaths, where short-term exposure could occur as shown in Drawing AQ1. The dispersion modelling of odour and point sources has also been completed using a receptor grid, so that concentrations can be determined at any location surrounding the site. SLR Agrivert Limited: Courteenhall AD Facility 15 402.2367.00001 Local Air Quality Assessment August 2008 5.0 ODOUR ASSESSMENT 5.1 Identification of Odour Sources Potential odour sources associated with the proposed development have been identified by consideration of details of the operations proposed on the application site. Typically odour will potentially be generated as a result of handling and processing wastes with a biodegradable fraction and the storage of silage on site. The aspects of the proposed development which will have the potential to generate odour beyond that which would be expected for the baseline situation are limited to the operational phase of the proposed development and are as follows: • reception building operations (waste receipt and handling); • storage of maize (energy crop) in silage clamp; • processing of waste; and • export of digestate from storage tanks for distribution. All other aspects of the proposed development are not considered to be significant odour sources and have not been considered further. 5.1.1 Description of Odour Sources and designed-in Mitigation Reception Building (waste receipt and handling) Operations including waste receipt and handling undertaken within the reception building would have the potential for odorous emissions to arise if the designed-in odour abatement technologies were absent. The designed-in mitigation measures include: • Fast acting roller-shutting doors; • negative pressure ventilation system; and • biofiltration of extracted air prior to discharge to atmosphere. Given the controls that would be employed, it is considered that all odorous emissions arising from the reception building would be emitted through the biofilter. Two biofilters would be installed at the facility, to provide backup in the event of failure of one biofilter. Each biofilter would be 100m2 in area (10m x 10m) and 2m high with bark / woodchip filter material to a depth of 1.6m. Each has a treatment facility of 20,000m3 per hour, giving a retention time of approximately 30 seconds within the media, which is considered suitable for abatement of odours of this type. Extracted air would be maintained at a suitable humidity content using a humidification chamber to ensure saturation does not occur and to avoid dust blockages. Moisture control minimises the risk of shrinkage and crusting within the biofilter material, thus ensuring that short circuiting (uneven air flow) does not occur. During prolonged hot periods of weather, a surface irrigation system would be employed if required. Replacement of the biofilter media would be undertaken as necessary, typically within the time range of 3 to 7 years. Maize Silage Clamp In order for the proposed facility to accept a variety of waste streams, an energy crop silage will be used in the process to act as a balancing feedstock. The energy crop silage would be SLR Agrivert Limited: Courteenhall AD Facility 16 402.2367.00001 Local Air Quality Assessment August 2008 stored on site in a silage clamp on a concrete pad and delivered on a daily basis to the energy crop reception bunker. Odorous emissions from the storage of the maize energy crop on site would be contained using a silage ‘clamp’ system comprising of push walls and a tarpaulin cover, a similar practice to that of traditional farm silage clamps. The entire surface of the maize storage would be enclosed with the exception of the front end of the store, required for transferring the maize to the digester tanks. Effluent arising from the silage clamp would be captured by a drainage grid and used within the process. The potential for odour emissions from the silage clamp are therefore expected to be small and only occur through the exposure of a small area of the maize to the digesters. The area of exposure would, at its maximum, be an area of 450m2 (90m x 5m). Digesters and Storage Tanks The anaerobic digestion process leads to the generation of volatile organic compounds, including of course methane which is fed to the gas engines. If unmitigated this source is considered to have the greatest potential to lead to the detection of odours at sensitive receptor locations with the potential to cause annoyance. The primary and secondary digesters and storage tankers are fully contained air tight containers with the biogas (methane) extracted to gas engines. The off-gas is combusted in the gas engines which leads to the effective destruction of odorous compounds. Consequently this source is considered to be fully abated. Removal of Digestate for Application Offsite The product digestate is stored within large sealed tanks for up to 6 months prior to the use of this material as a ‘biofertiliser’ for crops on the adjacent farmland. As with the digesters, the storage tanks are fitted with roofs to capture any residual biogas emitted during storage to maximise energy production. When the digestate is ready to be applied to the adjacent farmland (dependent on seasonal factors), the digestate is pumped into sealed tankers. This process is undertaken within the Reception Building. The digestate is then transported by the sealed tankers to a selected field where specialised slurry applicators apply the digestate in accordance with the relevant legislation. The operations associated with the removal of digestate from the application site do not therefore produce any potential odorous emissions given that at every stage the digestate is held within sealed containers. 5.2 Assessment of Impacts Following consideration of the designed-in odour abatement measures, the only potential odorous sources from the application site are the biofilters and the exposed area of the maize silage clamp which have been assessed though the application of dispersion modelling. 5.2.1 Derivation of Odour Emissions Rates The generation of odour emissions data for the dispersion modelling has been based on values given in published literature in the UK and Europe as detailed in the following SLR Agrivert Limited: Courteenhall AD Facility 17 402.2367.00001 Local Air Quality Assessment August 2008 sections (for a more detailed description of the odour model input parameters see Appendix B). Biofilter As a result of the designed-in odour control at the reception building, it is considered that all emissions from the handling and processing of waste within the building would be emitted through the biofilter. Potential odorous emissions from the biofilter have been based upon results from over 150 odour concentration measurements from biofilters serving composting plants14. The odour emission is calculated based on the estimated odour concentration multiplied by the designed volume air flow through the filter. Table 6: Biofilter Odour Emission Calculations (per unit) Parameter Value Length (m) 10 Width (m) 10 Cross Sectional Area (m2) 100 Height of release (m) 2 Depth of biofilter media (m) 1.6 Volume of biofilter media (m3) 160 Throughput of Biofilter (each) (m3/hour) 20,000 Residence Time (s) 29 3 Residual Odour Concentration (ouE/m ) 1,000 Odour Emission Rate (ouE/s) 5556 Energy Crop Silage The odour emission rate from the exposed area of the energy silage crop has been based upon professional experience from previous, similar developments such as green waste composting. Table 7: Energy Crop Silage Emission Calculations Parameter Value Length (m) 90 Width (m) 3 Cross Sectional Area (m2) 270 Height of release (m) 3 2 Specific Odour Emission Rate (ouE/m /s) 25 5.2.2 Predicted Impacts The odour impact of the proposed development is presented in Drawing AQ2. The predicted impact at sensitive receptor locations is presented in Table 8 below. For identified sensitive 14 Biowaste Composting - New Developments and Solutions for the Reduction of Odour Emissions - Adam Srecker Biofilter - Practical Experiences from Plant Monitoring SLR Agrivert Limited: Courteenhall AD Facility 18 402.2367.00001 Local Air Quality Assessment August 2008 receptors the minimum, maximum and annual average concentration has been presented for the 5 years of results. Table 8: Odour Impact at Receptor Locations Odour Concentration C ou /m3 (n=5) Receptor 98, 1 hour E Minimum Maximum Average R2 Courteenhall West Lodge 0.85 1.28 1.08 R3 West Lodge Cottages 1.39 1.95 1.63 R4 The Lodge 0.32 0.58 0.43 R5 Bridge Cottage 0.12 0.25 0.17 R6 Woodleys Farm 0.25 0.50 0.32 R7 Gamekeepers Cottage 0.08 0.13 0.10 R8 Thorpewood Farm 0.03 0.05 0.04 R9 Roade (north) 0.02 0.04 0.03 R10 Hyde Farm 0.02 0.06 0.04 R11 Blisworth Lodge Farm 0.01 0.01 0.01 R12 Manor Farm 0.01 0.02 0.02 R13 Grange Park 0.04 0.06 0.05 The results of the odour impact assessment are shown in Drawing AQ2 and indicates that 3 3 there will be no exceedence of either the C98, 1 hour 5ouE/m or theC98, 1 hour 3ouE/m limit criterion at any identified sensitive receptor. The receptor location likely to experience the 3 greatest impacts is at West Lodge Cottages at C98, 1 hour 1.63 ouE/m , approximately 33% of the limit criterion. The impact at Receptor 2, Courteenhall West Lodge, is C98,1 hour 1.08 3 ouE/m , approximately 22% of the criterion. Approximately one third of the modelled odour impact will result from the exposed area of silage and the remainder from the treated emissions from the biofilter. On this basis, whilst offsite odours may be perceptible from time to time, the concentration and frequency of odours is considered to be acceptable. 5.2.3 Mitigation and Enhancement Measures All mitigation measures (such as the enclosure and extraction of sources to the biofilter) are ‘designed in’ and it is therefore not appropriate to consider the impacts without them. 5.3 Residual Significant Impacts Atmospheric dispersion modelling of the predicted impact of the proposed development after application of designed-in mitigation measure shows there are no residual significant odour impacts. SLR Agrivert Limited: Courteenhall AD Facility 19 402.2367.00001 Local Air Quality Assessment August 2008 6.0 COMBUSTION PRODUCTS - POINT SOURCES 6.1 Proposed development – Point Sources Point sources of combustion products at the proposed development have been identified by consideration of details of the operations proposed and are as follows: • 2 No. cogeneration Combined Heat and Power (CHP) gas engines; and • 1 No. Biogas Flare. The following pollutants are considered to be potentially released from these sources as detailed in Table 9 below. Table 9: Point Sources and Emissions Source Pollutant Gas Engines NO2 PM10 SO2 CO BaP HCl Flare NO2 SO2 CO The biogas flare will only operate in emergency and maintenance situations when biogas will be diverted from the engines to the flare. This is likely to be for less than 200 hours per year (<3% of the year) and is therefore a ‘standby’ unit. Furthermore the emission rate of pollutants from a flare is lower than those from the engines, and exhaust gases will be at higher temperatures. Emissions from the flare have therefore not been considered further in the assessment. 6.2 Assessment of Impacts As with the odour modelling, the Atmospheric Dispersion Model used for the assessment was BREEZE AERMOD GIS version 6. For further details of the model, topographical and meteorological data and GIS capability refer to Appendix B. 6.2.1 Derivation of Pollutant Emission Rates The emission parameters input into the dispersion model are presented in Table 10 below. The Agency document Guidance for monitoring landfill gas engine emissions15 and monitoring research16 has been used to derive pollutant concentration for the plant as it will be powered by biogas (methane) from the anaerobic digesters, the exhaust is therefore considered likely to have similar emissions to a landfill gas engine. 15 Environment Agency, Guidance for monitoring landfill gas engine emissions LFTGN08, (September 2004) 16 Land Quality Management Ltd, Landfill Gas Engine Exhaust and Flare Emissions (September 2002) SLR Agrivert Limited: Courteenhall AD Facility 20 402.2367.00001 Local Air Quality Assessment August 2008 Table 10: Engine Pollutant Emissions Parameters Parameters Units CHP Plant 1 CHP Plant 2 x OS (m) 475028.3 475030.2 Location y OS (m) 253136.3 253136.3 Engine - Jenbacher 320 Jenbacher 320 Stack height m 12m 12m Release temperature K 456 456 Efflux velocity m/s 28.8m/s 28.8m/s Stack diameter m 0.3 0.3 Flow rate (Actual) Am3/s 2.04 2.04 Flow rate (Normalised) Nm3/s 0.89 0.89 3 NOx Emission Level mg/m 650 650 3 PM10 Emission Level mg/m 10 10 BaP Emission Level mg/m3 0.001 0.001 CO Emission Level mg/m3 1500 1500 HCl Emission Level mg/m3 20 20 d NOx Emission Rate g/s 0.58 0.58 d PM10 Emission Rate g/s 0.01 0.01 BaP Emission Rated g/s 0.0000009 0.0000009 CO Emission Rated g/s 1.33 1.33 e SO2 Emission Rate g/s 0.07 0.07 HCl Emission Rated g/s 0.02 0.02 Reference Sources: a) Environment Agency, Guidance for monitoring landfill gas engine emissions LFTGN08, (September 2004) b) Land Quality Management Ltd, Landfill Gas Engine Exhaust and Flare Emissions (September 2002) c) Environment Agency, IPPC Sector Guidance Note – Combustion Activities, (2002) d) Emission rates of NOX, PM10, BaP, CO and HCL based upon the normalised flow rate and the relevant emission level. e) SO2 emission rate based upon a maximum concentration of 250ppm H2S in the inlet gas, representing the highest concentration before corrosive damage occurs on the engine. Nitric Oxide to Nitrogen Dioxide Conversion Oxides of nitrogen (NOx) emitted to atmosphere as a result of combustion will consist largely of nitric oxide (NO), a relatively innocuous gas. Once released into the atmosphere, NO is oxidised to NO2. The proportion of NO converted to NO2 depends on a number of factors including wind speed, distance from the source, solar irradiation and the availability of oxidants, such as ozone (O3). Guidance from AQMAU17 states that ‘for short-term impacts, convert all measured or estimated nitrogen oxide emissions to NO2 and assume 50 per cent of this value when making comparisons with the short term NO2 environmental benchmark’. Therefore, the modelled NOx impact has been corrected by a factor of 0.5 to represent the impact of NO2 for short term (1-hour) impact. 17 Environment Agency Air Quality Modelling and Assessment Unit (AQMAU). Online resource, available at http://www.environment-agency.gov.uk SLR Agrivert Limited: Courteenhall AD Facility 21 402.2367.00001 Local Air Quality Assessment August 2008 Total oxidation has been assumed for comparison of predicted concentrations with the long- term objective for NO2. Therefore, 100% of the NOx value has been used to show annual average impact of NO2. 6.2.2 Dispersion Modelling Results Nitrogen Dioxide: Long Term (annual) The maximum predicted long term process contribution of nitrogen dioxide from the proposed development at relevant receptor locations is 6.9µg/m3, 17.3% of the EAL of 40µg/m3. The maximum Predicted Environmental Concentration (PEC) is 62.7% of the EAL and therefore long-term impacts of nitrogen dioxide are not considered to be significant (according to the H1 criteria). As impacts are not classified as insignificant, a summary of the PC and PEC concentrations for each relevant discrete receptor is shown below in Table 11. Table 11: Predicted Long Term Nitrogen Dioxide Impacts PC PEC Receptor PC % EAL PEC % EAL µg/m3 µg/m3 R2 Courteenhall West Lodge 2.86 7.1% 21.01 52.5% R3 West Lodge Cottages 6.92 17.3% 25.07 62.7% R4 The Lodge 2.50 6.3% 20.65 51.6% R5 Bridge Cottage 1.91 4.8% 20.06 50.1% R6 Woodleys Farm 1.50 3.8% 19.65 49.1% R7 Gamekeepers Cottage 0.71 1.8% 18.86 47.1% R8 Thorpewood Farm 0.32 0.8% 18.47 46.2% R9 Roade (north) 0.24 0.6% 18.39 46.0% R10 Hyde Farm 0.26 0.6% 18.41 46.0% R11 Blisworth Lodge Farm 0.07 0.2% 18.22 45.6% R12 Manor Farm 0.17 0.4% 18.32 45.8% R13 Grange Park 0.37 0.9% 18.52 46.3% Nb, Receptors R1 and R14 are not included within assessment as they are classified as working agricultural buildings and therefore assessed for short term impacts only. Nitrogen Dioxide: Short Term (hourly) The maximum predicted short term process contribution of nitrogen dioxide from the proposed development at relevant receptor locations is 102.3µg/m3, 51.2% of the EAL of 40µg/m3 at the closest point of potential public exposure (Courteenhall Road). The maximum predicted PEC is 138.6µg/m3. This represents 69.3% of the EAL of 200µg/m3 and therefore short-term impacts of nitrogen dioxide are not considered to be significant (according to the H1 criteria). As impacts are not classified as insignificant, a summary of the of PC and PEC concentrations at the relevant receptor locations is shown in Table 12. SLR Agrivert Limited: Courteenhall AD Facility 22 402.2367.00001 Local Air Quality Assessment August 2008 Table 12: Predicted Short Term Nitrogen Dioxide Impacts PC PEC Receptor PC % EAL PEC % EAL µg/m3 µg/m3 R1 West Lodge Farm Building 31.95 16.0% 68.25 34.1% R2 Courteenhall West Lodge 29.39 14.7% 65.69 32.8% R3 West Lodge Cottages 50.12 25.1% 86.42 43.2% R4 The Lodge 39.22 19.6% 75.52 37.8% R5 Bridge Cottage 32.76 16.4% 69.06 34.5% R6 Woodleys Farm 28.43 14.2% 64.73 32.4% R7 Gamekeepers Cottage 11.07 5.5% 47.37 23.7% R8 Thorpewood Farm 7.02 3.5% 43.32 21.7% R9 Roade (north) 5.81 2.9% 42.11 21.1% R10 Hyde Farm 6.23 3.1% 42.53 21.3% R11 Blisworth Lodge Farm 1.96 1.0% 38.26 19.1% R12 Manor Farm 3.75 1.9% 40.05 20.0% R13 Grange Park 4.41 2.2% 40.71 20.4% R14 West Lodge Farm Building 60.97 30.5% 97.27 48.6% PRa Maximum at Receptor 102.30 51.2% 138.60 69.3% a) Maximum receptors taken as the nearest point of public exposure i.e. nearest public road / track in each direction from the facility and not the installation boundary Carbon Monoxide: Short term (8 Hour Running Mean) The maximum predicted short term process contribution of carbon monoxide from the proposed development at relevant receptor locations is 367.8µg/m3, 3.7% of the EAL for carbon monoxide of 10,000µg/m3. The impacts of carbon monoxide are therefore classified as insignificant (according to the H1 criteria) and have therefore not been reported in full. PM10: Long Term (annual) The maximum predicted long term process contribution of PM10 from the proposed 3 development at relevant receptor locations is 0.12µg/m , 0.3% of the EAL for PM10 of 3 40µg/m . The long term impacts of PM10 are therefore classified as insignificant (according to the H1 criteria) and have therefore not been reported in full. PM10: Short Term (24 hour) The maximum predicted short term process contribution of PM10 from the proposed 3 development at relevant receptor locations is 0.88µg/m , 1.9% of the 24 hour EAL for PM10 3 of 50µg/m . The short term impacts of PM10 are therefore classified as insignificant (according to the H1 criteria) and have therefore not been reported in full. Sulphur Dioxide: Long term (annual) The maximum predicted long term process contribution of sulphur dioxide from the proposed development at relevant receptor locations is 0.79µg/m3, 1.6% of the EAL for sulphur dioxide of 50µg/m3. The maximum PEC of sulphur dioxide is 2.91µg/m3. This represents 2.3% of the long term EAL for sulphur dioxide of 50µg/m3 and therefore long-term impacts of sulphur dioxide are not considered to be significant (according to the H1 criteria). SLR Agrivert Limited: Courteenhall AD Facility 23 402.2367.00001 Local Air Quality Assessment August 2008 As impacts are not classified as insignificant, a summary of the PC and PEC concentrations for each relevant discrete receptor is shown below in Table 13. Table 13: Predicted Long Term Sulphur Dioxide Impacts PC PEC Receptor PC % EAL PEC % EAL µg/m3 µg/m3 R2 Courteenhall West Lodge 0.33 0.65% 2.45 2.0% R3 West Lodge Cottages 0.79 1.58% 2.91 2.3% R4 The Lodge 0.29 0.57% 2.41 1.9% R5 Bridge Cottage 0.22 0.44% 2.34 1.9% R6 Woodleys Farm 0.17 0.34% 2.29 1.8% R7 Gamekeepers Cottage 0.08 0.16% 2.20 1.8% R8 Thorpewood Farm 0.04 0.07% 2.16 1.7% R9 Roade (north) 0.03 0.05% 2.15 1.7% R10 Hyde Farm 0.03 0.06% 2.15 1.7% R11 Blisworth Lodge Farm 0.01 0.02% 2.13 1.7% R12 Manor Farm 0.02 0.04% 2.14 1.7% R13 Grange Park 0.04 0.09% 2.16 1.7% Nb, Receptors R1 and R14 are not included within assessment as they are classified as working agricultural buildings and therefore assessed for short term impacts only. Sulphur Dioxide: Short term (24 Hour Average) The maximum predicted short term (24-hr average) process contribution of sulphur dioxide at relevant receptor locations is 3.43µg/m3, 2.7% of the EAL of 125µg/m3. The short term (24-hr average) impacts of sulphur dioxide are therefore classified as insignificant (according to the H1 criteria) and have therefore not been reported in full. Sulphur Dioxide: Short Term (1 Hour) The maximum predicted short term (1-hr) process contribution of sulphur dioxide at relevant receptor locations is 23.04µg/m3, 6.6% of the EAL of 350µg/m3. The short term (1-hr) impacts of sulphur dioxide are therefore classified as insignificant (according to the H1 criteria) and have therefore not been reported in full. Hydrogen Chloride: Long Term (annual) The maximum predicted process contribution of hydrogen chloride from the proposed development at relevant receptor locations is 0.24µg/m3, 1.2% of the EAL. The maximum PEC of hydrogen chloride is 0.71µg/m3. This represents 3.5% of the long term EAL of 20µg/m3 and therefore the long term impacts of hydrogen chloride are not significant (according to the H1 criteria). As impacts are not classified as insignificant, a summary of the PC and PEC concentrations for each relevant discrete receptor is shown in Table 14. SLR Agrivert Limited: Courteenhall AD Facility 24 402.2367.00001 Local Air Quality Assessment August 2008 Table 14: Predicted Long Term Hydrogen Chloride Impacts PC PEC Receptor PC % EAL PEC % EAL µg/m3 µg/m3 R2 Courteenhall West Lodge 0.10 0.5% 0.57 2.8% R3 West Lodge Cottages 0.24 1.2% 0.71 3.5% R4 The Lodge 0.09 0.4% 0.56 2.8% R5 Bridge Cottage 0.07 0.3% 0.54 2.7% R6 Woodleys Farm 0.05 0.3% 0.52 2.6% R7 Gamekeepers Cottage 0.02 0.1% 0.49 2.5% R8 Thorpewood Farm 0.01 0.1% 0.48 2.4% R9 Roade (north) 0.01 <0.1% 0.48 2.4% R10 Hyde Farm 0.01 <0.1% 0.48 2.4% R11 Blisworth Lodge Farm 0.00 <0.1% 0.47 2.4% R12 Manor Farm 0.01 <0.1% 0.48 2.4% R13 Grange Park 0.01 0.1% 0.48 2.4% Nb, Receptors R1 and R14 are not included within assessment as they are classified as working agricultural buildings and therefore assessed for short term impacts only. Hydrogen Chloride: Short Term The maximum predicted short term (1-hr) process contribution of hydrogen chloride at relevant receptor locations is 8.99µg/m3, 1.1% of the EAL of 800µg/m3. The short term (1-hr) impacts of hydrogen chloride are therefore classified as insignificant (according to the H1 criteria) and have therefore not been reported in full. PAHs: Long term (annual; modelled as Benzo[a]Pyrene) The maximum predicted process contribution of Benzo[a][Pyrene from the proposed development at relevant receptor locations is 0.011ng/m3, 4.3% of the EAL. The maximum PEC of Benzo[a][Pyrene is 0.15ng/m3, This represents 60.3% of the EAL of 0.25ng/m3 and therefore the long term impacts of Benzo[a]Pyrene are not significant (according to the H1 criteria). As impacts are not classified as insignificant, a summary of the PEC concentrations for each relevant discrete receptor is shown in Table 15. SLR Agrivert Limited: Courteenhall AD Facility 25 402.2367.00001 Local Air Quality Assessment August 2008 Table 15: Predicted Long Term Benzo[a][Pyrene Impacts PC PEC Receptor PC % EAL PEC % EAL ng/m3 ng/m3 R2 Courteenhall West Lodge 0.004 1.8% 0.144 57.8% R3 West Lodge Cottages 0.011 4.3% 0.151 60.3% R4 The Lodge 0.004 1.6% 0.144 57.6% R5 Bridge Cottage 0.003 1.2% 0.143 57.2% R6 Woodleys Farm 0.002 0.9% 0.142 56.9% R7 Gamekeepers Cottage 0.001 0.4% 0.141 56.4% R8 Thorpewood Farm <0.001 0.2% 0.141 56.2% R9 Roade (north) <0.001 0.2% 0.140 56.1% R10 Hyde Farm <0.001 0.2% 0.140 56.2% R11 Blisworth Lodge Farm <0.001 0.1% 0.140 56.0% R12 Manor Farm <0.001 0.1% 0.140 56.1% R13 Grange Park <0.001 0.2% 0.141 56.2% Nb, Receptors R1 and R14 are not included within assessment as they are classified as working agricultural buildings and therefore assessed for short term impacts only. 6.2.3 Mitigation and Enhancement Measures All mitigation measures (such as release of combustion pollutants through elevated stacks) are ‘designed in’ and it is therefore not appropriate to consider the impacts without them. 6.3 Residual Significant Impacts There are no significant short or long term significant residual impacts associated with combustion products from point sources. SLR Agrivert Limited: Courteenhall AD Facility 26 402.2367.00001 Local Air Quality Assessment August 2008 7.0 CONCLUSIONS 7.1 Approach This report assesses the potential significant impacts of the proposed development in terms of Air Quality. The report describes the assessment methodology, the baseline conditions currently existing at the application site and surroundings, the likely significant source of emission, the designed-in mitigation measures and the likely residual impacts after these mitigation measures have been implemented. The assessments have been undertaken and reported using the latest and most appropriate UK guidance and all modelling has been undertaken using appropriate models. 7.2 Results The results of the assessment demonstrate the requirement for designed-in and ongoing operational mitigation at this site. In particular, the site has the potential to generate odours which can be effectively mitigated through correct maintenance of the odour control equipment (containment, extraction and treatment) and day-to-day operational practice (such as site cleanliness). Subject to all appropriate mitigation described in the report being adopted at this site, it can be concluded that: • odour impacts will be within acceptable limits and unlikely to cause annoyance; and • impacts of point source emissions of combustion products will not be significant (according to the H1 criteria) and will be within EAL’s for all pollutants. SLR APPENDICIES SLR APPENDIX A Appendix A: Detailed Modelling Inputs Detailed Dispersion Modelling Checklist Document EPR H1 appendix C provides guidance relating to the structure of dispersion modelling reports, and includes a dispersion modelling report checklist. to aide the reviewer to determine the appropriateness of reporting. Dispersion model checklist Location Map and Site Plan Included with supporting statement and Drawing AQ1 List of pollutants modelled and A table of pollutants modelled and relevant EAL’s is included in relevant air quality guidelines the report. H1 screening was omitted with all pollutants progressing directly onto detailed modelling. Details of modelled scenarios The scenario considering the plant running 24 hours per day 365 days per year has been considered. A precautionary approach has been adopted and flare emissions have not been considered as the flare will only be used in maintenance situations and presents less risk than other sources. Details of relevant ambient All ambient concentrations were based upon background concentrations used levels provided at www.airquality.co.uk . Model description and Trinity Consultants version of US EPA AERMOD v6 was used justification in accordance with guidance issued by the Environment Agency Air Quality Modelling Assessment Unit. This is an advanced dispersion model and appropriate for modelling situations and pollutants such as those relevant in this study. Special model treatments used None. Table of emission parameters A table of emission parameters is included in the report used Details of modelled domain and A table of discrete receptors is included in the report and the receptors following gridded receptors applied: Odour: 2km x 2km (SW corner NGR 474050, 252200) at a resolution of 50m. Combustion sources: 3km x 3km (SW corner NGR 473500, 251700) at a resolution of 100m & a finer 1km x 1km grid (SW corner NGR 474600, 252700) with a resolution of 25m was also located over the installation. Details of meteorological data AERMOD meteorological data (surface and profile files) for the used (including origin) and five years 1999 to 2003 inclusive was obtained for Bedford justification Observation Station from Trinity Consultants. Details of terrain treatment Terrain included from .ntf file SP64 Details of building treatment Buildings taken into consideration in the model using AERMODS BPIP module are detailed in Appendix B. Sensitivity analysis No impacts are classified as significant and therefore no sensitivity analysis has been undertaken. Assessment of impacts Impacts have been assessed against Air Quality Strategy objectives for each pollutant where available or EALs where they are not. SLR APPENDIX B APPENDIX B DISPERSION MODEL INPUT DATA SLR APPENDIX B Description of Atmospheric Dispersion Modelling The Atmospheric Dispersion Model used for the assessment was BREEZE AERMOD GIS version 6, this is an advanced dispersion model and is accepted for use by the Environment Agency. The model incorporates the odour emission parameters of each source (e.g. release rate, height, and temperature), meteorological data, terrain data, sensitive receptor locations. A number of commercially available dispersion models are able to predict ground level concentrations arising from emissions to atmosphere. No dispersion model is wholly accurate and all models will produce variations in results under certain conditions. For this assessment the AERMOD GIS PRIME model18 has been applied. The AERMOD dispersion modelling program is widely used and accepted by the Environment Agency in the UK for undertaking such assessments and its predictions have been validated against real-time monitoring data by the USEPA19. It is therefore considered a suitable model for this assessment. AERMOD utilises digital elevation data to determine the impact of topography on dispersion from a source. Topographical data for the site has been obtained in OS digital (.ntf) format. AERMOD incorporates local meteorological data in order to calculate the dispersion of emissions in the environment. Five years data, covering the period 1999 to 2003 inclusive were used in the model. AERMOD incorporates a Geographical Information System (GIS) capability. The GIS is used to register Ordnance Survey data at 1:10000 resolution. This is used to correctly register the locations of all sources and receptor locations (e.g. residencies, schools, etc). Meteorological pre-processing The meteorological data for Bedford Observation Station was obtained in .met format from the data supplier and converted to .the required surface and profile formats for use in AERMOD using AERMET Pro (v6.2) meteorological pre-processor. Details specific to the exact site location are required for the pre-processing, such as latitude, longitude and surface characteristics. Given the varying nature of the surface features in the vicinity of the site, the surface characteristics were divided into five sectors and applied as shown below in accordance with the latest guidance20. Met Data Preparation – Applied Surface Characteristics Zone Zone Dominant Albedo Bowena Surface (Start) (end) Landscape Roughness Character 0 45 Cultivated Land 0.254 0.958 0.172 45 165 Coniferous Forest 1.038 165 215 Cultivated Land 0.288 18 Software used: BREEZE AERMOD GIS Pro, v6.2. 19 AERMOD: Latest Features and Evaluation Results. USEPA Report: EPA-454/R-03-003 June 2003, (http://www.epa.gov/scram001/dispersion_prefrec.htm#aermod) 20 AERMOD Implementation guide. AERMOD implementation workgroup, USEAP. Last revised January 8, 2008. SLR APPENDIX B Zone Zone Dominant Albedo Bowena Surface (Start) (end) Landscape Roughness Character 215 280 Cultivated Land 0.273 280 360 Cultivated Land 0.442 a) Bowen Ration based upon assessment of land-use in 10x10km grid surrounding Application Site being 68% Cultivated Land, 23% Urban and 9% Coniferous Forest. Windroses for Individual Years Bedford Meteorological Station - Windrose 1999 10% 8% 10 + m/s 6% 8 - 10 m/s 4% 6 - 8 m/s 2% 4 - 6 m/s 0% 3 - 4 m/s 2 - 3 m/s 0.5 - 2 m/s <0.5 m/s SLR APPENDIX B Bedford Meteorological Station - Windrose 2000 10% 8% 10 + m/s 6% 8 - 10 m/s 4% 6 - 8 m/s 2% 4 - 6 m/s 0% 3 - 4 m/s 2 - 3 m/s 0.5 - 2 m/s <0.5 m/s Bedford Meteorological Station - Windrose 2001 10% 8% 10 + m/s 6% 8 - 10 m/s 4% 6 - 8 m/s 2% 4 - 6 m/s 0% 3 - 4 m/s 2 - 3 m/s 0.5 - 2 m/s <0.5 m/s SLR APPENDIX B Bedford Meteorological Station - Windrose 2002 10% 8% 10 + m/s 6% 8 - 10 m/s 4% 6 - 8 m/s 2% 4 - 6 m/s 0% 3 - 4 m/s 2 - 3 m/s 0.5 - 2 m/s <0.5 Bedford Meteorological Station - Windrose 2003 10% 8% 10 + m/s 6% 8 - 10 m/s 4% 6 - 8 m/s 2% 4 - 6 m/s 0% 3 - 4 m/s 2 - 3 m/s 0.5 - 2 m/s <0.5 SLR APPENDIX B Odour Assessment Input Data AERMOD provides various methods for modelling different sources, such as the use of an area, point or volume source. Using an area source assumes that there is no exit velocity of the emission and does not take into account the effects of building downwash. Point sources assume the emissions has an exit velocity and models the effect of building downwash. The energy crop silage is modelled as an area source, given its relatively low height and that any emisison would not have an exit velocity. The biofilters would typically be seen as an area source given that each biofilter is 2m high with an area of 100m2. This model scenario however would not allow for an exit velocity to be added to the model or for the effects of building downwash to be accounted for. Although very small, the biofilters would produce gas with an exit velocity. On this basis, the biofilters as a number of point sources, thereby allowing building downwash to be taken into account. Described below is the emission input data used for the detailed odour modelling. It has been summarised by source. Odour Emission Rates and Release Parameters Energy Crop Parameter Biofilter No. 1 Biofilter No. 2 Silage Source Type Point Point Area 475018.5 475019.6 475022.6 475023.6 X Coordinate 475123.6a 475019.2 475020.0 475023.2 475024.0 253120.9 253110.9 253121.3 253111.4 Y Coordinate 253147.1a 253116.4 253106.6 253116.9 253107.2 Emission rate (ouE/s) 1389 (x4) 1389 (x4) 25 Height of release (m) 2 2 2 Dimensions (m) - - 3 x 90 Applied diameter (m) 5.64 5.64 - Exit Velocity (m/s) 0.056 0.056 - Temperature (°C) 25 25 - a) Coordinates taken at southern corner of source. SLR APPENDIX B The following table provides a description of buildings taken into consideration in the model. A graphical presentation of the modelled buildings can be seen below. SLR APPENDIX B Modelled Buildings Height X length y Length Building Number Tier Description X Y Angle (°) Radius (m) (m) (m) (m) 1 1 Existing Farm Building 474924.3 253139.4 12.0 17.8 58.2 84.1 - 2 1 Engine No. 1 475023.5 253148.4 3.0 12.2 3.0 81.5 - 3 1 Engine No. 2 475027.8 253149 3.00 12.2 3.0 81.5 - 1 9.0 35.4 31.4 83.0 - 2 10.0 35.4 21.0 83.0 - 4 Reception Building 475024.2 253135.8 3 11.0 35.4 12.2 83.0 - 4 11.8 35.4 4.0 83.0 - 5 1 Energy Silage Clamp 475116.5 253153.1 3.0 90 24 41.4 - 1 5.0 - - - 16.2 2 7.0 - - - 12.0 6 3 Storage Tank 1 475001.6 253138.3 9.0 - - - 9.0 4 11.0 - - - 6.0 5 12.1 - - - 3.0 7 1 Flare 475040.5 253159.8 7.0 - - - 1.5 1 5.0 - - - 17.5 2 7.0 - - - 13.0 8 3 Secondary Digester 475076.4 475076.4 9.0 - - - 9.0 4 11.0 - - - 5.0 5 12.1 - - - 2.0 1 5.0 - - - 17.5 2 7.0 - - - 13.0 9 3 Primary Digester No. 2 475109.8 253127.3 9.0 - - - 9.0 4 11.0 - - - 5.0 5 12.1 - - - 2.0 SLR APPENDIX B Height X length y Length Building Number Tier Description X Y Angle (°) Radius (m) (m) (m) (m) 1 5.0 - - - 17.5 2 7.0 - - - 13.0 10 3 Primary Digester No. 1 475081.5 253103.2 9.0 - - - 9.0 4 11.0 - - - 5.0 5 12.1 - - - 2.0 1 5.0 - - - 16.2 2 7.0 - - - 12.0 11 3 Storage Tank 2 475008.2 253094.0 9.0 - - - 9.0 4 11.0 - - - 6.0 5 12.1 - - - 3.0 12 1 Biofilter 475015.1 253127.6 2.0 20 10 83 - * Ground Level across site assumed to be 112.00m, thereby taking into account site works prior to construction of facility. SLR 4'10 November 2008 Our Ref: TRJRRJEDP897lfhf - 5 NOV 2008 The Environmental DimensionPartnership 14 Inner Co urtyard Alan Smith Esq Whiteway Farmhouse Northamptonshire Wildlife Trust The Whiteway Lings House Ciren cester Billings Lings Gloucestershire GL7 7BA Northampton NN38BE t 012856 40640 f 01285 652545 By Post and By Email e info@e dp-uk.co.uk w www.edp-uk.co.uk Dear Alan Anaerobic Digestion Facility, Northamptonshire As per our discussions earlier this month, the Environmental Dimension Partnership LLP (EDP) has been commissioned by Agrivert to undertake an ecological review for a proposed anaerobic digestion facility at West Lodge Farm, Courteenhall, and Northamptonshire. The site centred at Ordnance Survey Grid Reference (OSGR) SP 750 531. The site consists of arable land with West Lodge Farm buildings immediately to the west, arable land to the north and east and a hedgerow to the south with Courteenhall Road beyond. The proposals include the creation of an anaerobic digestion facility that includes five tanks, a concrete pad for energy crop silage, hardsurfaced areas and a reception building . It is proposed the site will be accessed from Courteenhall Road. To create this access, approximately four trees will be lost and a small section of hedgerow removed . These proposals are detailed on the plans submitted by Agrivert in support of the application. The appraisal consisted of a desk study, walkover survey of the site and review of Agrivert's proposals. A summary of findings and recommendations in relation to any ecological matters identified are set out below. Methodology This section summarises the methodology that was used to undertake the investigations, which were required to inform the proposed development of the site, in line with the aims set out above. The desk study involved the collation of information from Northampton Biodiversity Records Centre, Multi-Agency Geographic Information for the Countryside (MAGIC') and Natural England's Nature on the Map2 . Biodiversity information was requested for an area of 5km radius for a site of European importance, a 2km radius for sites of national importance or less and 1km radius for species records. In light of the scope of the proposals, this area of search is considered more than sufficient to cover the potential zone of influence' of the proposed development. The desk study was undertaken during October 2008 and any pertinent information received is discussed below. Continued/... Environmental plannin g, design and management I W#IN magtc gov.ulr; f ' www.natyreonthemap org.uk services or landowners and developers J Zoneof Influence- the areas and resources that may be affected by the proposed development. IheEnvironmenlal Omen"on UP R09 ~l e l ed as a Iimned LJabilily Partner A walkover survey involved identifying and scoping any actual/potential protected or priority species and habitats within the site and its immediate environs. In addition, during the survey a potentially notable hedgerow was identified and further consideration was made of the likely value of this feature using the ecological criteria for "important" hedgerows listed within the Hedgerow Regulations 1997 (enclosed). The survey was undertaken on the nnd October 2008 during which the weather conditions were dry with approximately 20% cloud clover and an ambient air temperature of 13°C. Results Statutory Designations The site is not covered, either wholly or partially, by any statutory designations. However, there is a single national-level designation (SSSI) within 2km of the site. Roade Cutting SSSI was notified in 1986 and covers an area of 14.9 ha. It is located approximately O.23km west of the site boundary. The SSSI is designated due to its geological interest rather than being of any biological note, hence it is not considered pertinent in relation to an assessment of the ecological impact of these proposals. Non-statutory Designations The site is not covered wholly or partially by any non-statutory designations; however there are four Potential Wildlife Sites (PWS) that are located within 2km of the site boundary. Due to the size and nature of the proposed development, together with the spatial relationship and nature of the non-statutory designations, not all the PWS are considered to be pertinent to it. The non-statutory designation that could potentially be pertinent due to its proximity is Courteenhall Estate PWS, located approximately 0.12km east of the site boundary. In spite of its close proximity to the site, with regards to the nature of the designation and the development proposals, it is considered that both the construction and operational stages of the proposals would have no significant negative impact on the PWS designation. Courteenhall Estate PWS therefore receives no further consideration in this study. Habitats As a result of the information received during the desk study and the walkover survey, it is considered that the entire site is of little ecological value in its own right, given that it consists of a field under arable production. However, it is recognised that the hedgerow and associated trees that bound the southern edge of the site are of local importance. The roadside hedgerow includes a diverse number of woody species and also woodland species in its ground flora. Based on the assessment undertaken by EDP during the walkover survey, it is considered to fulfill the ecological criteria for "important" hedgerows as defined by the Hedgerow Regulations (1997). A completed survey sheet is included as Annex A of this letter. In addition, a number of semi-mature to mature poplar (Populus x canadensis) trees are associated with the hedgerow. Continued/... Alan Smith Esq edp TR/RR/EDP897/fhf 4th November 2008 -3 Protected and/or Notable species It is considered that, in relation to the habitat present on site, there are few opportunities for protected/notable species. With regards to bats, no records of roosts or foraging bats were received during the desk study. Negligible opportunities for roosting were recorded w ithin the vicinity of the site. The trees located on the southern boundary are of typically semi-mature to mature w ith no significant roosting features. The farm buildings and sheds on the western bounds of the site also provide negligible roosting opportunities due to their typical corrugated iron/asbestos structures . In relation to the negligible roosting opportunities within the vicinity of the development and the lack of suitable foraging habitat on site, bats are not considered a significant constraint to the proposed development. No records of great crested newts were received during the course of the desk study. No suitable aquatic habitat was recorded on site, with the closest ponds located approximately 0.25km south, O.22km north west and 0.40 km north east of the site boundary (locations and distances obtained from MAGIC!). The hedgerow could provide suitable terrestrial habitat for this species, however given the paucity of suitable terrestrial habitat within the vicinity of the site compared to the woodland habitat that surrounds the ponds on Courteenhall Estate and the distance of these ponds from the site, it is considered that the development would be unlikely to result in any significant adverse impacts on this species or their favourable conservation status (assum ing that they are present in the first place). Therefore great crested newts are not considered a constraint to the proposed development. Bird nests were recorded in the hedgerow to the south of the site and indeed, the arable field could potentially provide a small area of suitable habitat for ground nesting birds such as skylark. In relation to other legally protected species, given the habitats of the footprint and those areas immediately adjacent to it, it is not considered that there is a significant likelihood of other such species being present. Recommendations and Conclusions It is considered that a large proportion of the site is of little ecological value in its own right. The potential ecological constraints are detailed below together with recommendations for mitigation and opportunities for biodiversity gain. Hedgerows It is understood a short section of the hedgerow and approximately four trees will be removed to create the access road to the site. It is recognised that the proposals w ill result in a small loss of a hedgerow which fulfils the ecological criteria for "important" hedgerow under the Regulations. This impact will be mitigated through replacement planting and additional planting around the margins of the site. In order to ensure sufficient mitigation and to provide opportunities for ecological gain, it is recommended that this planting should use a high diversity of native tree and shrub species of local provenance and that they should be appropriately managed to ensure establishment. Continued/... Alan Smith Esq edp TR/RR/EDP897/fhf 4th November 2008 -4 Birds It is recognised that the site could provide breeding opportunities for birds with the key area of habitat likely to provide these opportunities being the hedgerow. Although a small section of the hedgerow will be removed for the access road it is understood that the proposals include a significant area of landscaping that will include shrub and tree planting. This will provide a net gain in this potential bird breeding habitat. It is recognised however that an area of open farmland , potentially providing breeding habitat for ground nesting birds such as skylark, would be lost through the proposed development. However, taking into account the relatively small footprint of the development and the wider arable landscape within which the proposals are located, it is considered that the potential negative impact on these species is negligible. Given that the site offers potential nesting opportunities for birds, in the form of hedgerow, trees and open arable farmland, certain timing constraints will need to be adhered to when these areas are disturbed or removed (if required). It is recommended that the removal of any potential nesting habitat should occur outside the bird breeding season (February to August, inclusive). unless no breeding birds are confirmed to be present by an ecologist immediately prior to the work commencing. Ecological Enhancement In addition to the enhancement provided by the additional hedgerow planting, it is recommended that four Schwegler 1B bird boxes are erected and positioned by suitably qualified personnel. In conclusion, it is considered that there are no significant ecological constraints to the proposed development and opportunities are provided for biodiversity gain proportional to the scale of the proposed development. I trust that the above meets with your approval, however if you do have any queries please do not hesitate to call me. With kind regards Yours sincerely Q /i~ n~ W PhD, BSc (Hons), MIEEM, CEnv Partner 07920027569 [email protected] F coloq ical cntena fo r "important hedgerows". Hedgerow Regulations ( 1997) cc: Gemma Kay - Agrivert Matt Johnston - Northamptonshire Wildlife Trust James Griffin - Northamptonshire County Council General Details "" ';,'1 La r A ; [,11" Z;2...1 \ 0 {uc6 II IlJl' tffl Field- Based Study W,l lk tlu- h (' d~ ll' on on 1)1 (wh ere ,l e t e ~ S is available) hath s i rl (' ~ and (fo l oach h t1 ge) record the foll owi ng infor mation: ,. 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