Environmental Impact Assessment in support of a Planning Application to extract Blisworth at Stonepits Quarry, Benefield

Version 1.2 May 2012

Report prepared for:

Churchfield Stone Ltd c/o PGR Construction 6 The Old Quarry Nene Valley Business Park Oundle PETERBOROUGH PE8 4HN

BARKERS CHAMBERS  BARKER STREET  SHREWSBURY  UNITED KINGDOM  SY1 1SB TEL: 01743 355770 FAX: 01743 357771 EMAIL: [email protected]

Environmental Impact Assessment in support of a Planning Application to extract Blisworth Limestone at Stonepits Quarry, Benefield

Version 1.2 May 2012

Prepared by: Checked by:

S Belton MSci, MSc, FGS H K MacLeod BSc, MSc, FGS

Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

CONTENTS

1 INTRODUCTION 1 1.1 Background 1 1.2 Objectives 1 1.3 Data sources 1

2 SITE SETTING 2 2.1 Location 2 2.2 Landform 2 2.3 Hydrology 2 2.3.1 Watercourses 2 2.3.2 Springs and wells 3 2.3.3 Ponds and waterbodies 3 2.3.4 Rainfall 3 2.3.5 Surface water abstractions 3 2.3.6 Source Protection Zones (SPZs) 3 2.3.7 Ecologically protected sites 4 2.4 Geology 4 2.4.1 Regional 4 2.4.2 Local geology 5 2.5 Hydrogeology 6 2.5.1 Aquifer status and regional context 6 2.5.2 Groundwater abstractions 6 2.5.3 Aquifer characteristics 6 2.5.4 Groundwater level and distribution 6 2.5.5 Hydraulic conductivity 7 2.5.6 Baseline groundwater quality 8 2.6 Conceptual hydrogeological model 8

3 PROPOSED DEVELOPMENT 9 3.1 Overview 9 3.2 Water management 9 3.2.1 Radius of influence of dewatering 9 3.2.2 Discharge requirements 10 3.2.3 Rainfall/run-off 10 3.3 Restoration 10

4 ASSESSMENT OF IMPACTS AND MITIGATION MEASURES 11 4.1 Catchment sensitivity 11 4.2 Water quality 11 4.2.1 Hydrocarbons 11 4.2.2 Suspended solids 12 4.3 Groundwater levels 12 4.3.1 Groundwater flow and surface water flow 12 4.4 Groundwater and surface water abstractions 13 4.5 Springs 13 4.6 Ecologically protected sites 13 4.7 Post-operational impacts 13

5 CUMULATIVE IMPACTS 15

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6 SUMMARY AND CONCLUSIONS 16

FIGURES

Figure 1 Site location and water features Figure 2 Geology Figure 3 Borehole and trial pit locations Figure 4a Inferred top of Blisworth Limestone Figure 4b Inferred base of Blisworth Limestone Figure 5 Bedrock aquifer designation Figure 6 Hydrographs Figure 7 Phasing plans

PHOTOSHEETS

Photosheet 1 Watercourses, sinkhole and spring Photosheet 2 Downstream of spring and view northeast

APPENDICES

Appendix 1 SSSI citation Appendix 2 Borehole logs and data Appendix 3 Groundwater level data Appendix 4 Analysis of rising and falling head tests Appendix 5 Discharge calculations Appendix 6 Methodology for impact assessment

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1 INTRODUCTION

1.1 Background

Churchfield Stone Ltd is seeking permission to extract Blisworth Limestone at a greenfield site, referred to as Stonepits Quarry, located near to Upper Benefield, East Northamptonshire.

An Environmental Impact Assessment (EIA) has been requested in support of the Planning Application. Hafren Water has been commissioned by Churchfield Stone Ltd to undertake an assessment of the extant water environment and to investigate the potential impacts associated with the Application. Planning consultants GP Planning Ltd has prepared the Planning Application on behalf of Churchfield Stone Ltd.

1.2 Objectives

The principal objectives of this study are to:

. Determine baseline conditions in relation to the water environment at Stonepits Quarry and its surroundings. . Determine a hydrogeological conceptual model for the site. . Identify potential impacts of the proposed development. . Assess the magnitude and significance of potential impacts. . Derive appropriate mitigation measures for any identified potential impacts.

1.3 Data sources

The following sources of data were used in this study:

British Geological Survey (BGS) 1:50,000 scale geological maps: 171 Kettering

Ordnance Survey (OS) Landranger 1:50,000 scale map, Sheet 141 Kettering and Corby Explorer 1:25,000 scale map, Sheet 224 Corby, Kettering and Wellingborough Explorer 1:25,000 scale map, Sheet 227 March, Whittlesey, Chatteris & Oundle

The Environment Agency (EA) Licensed abstractions Rainfall Surface water quality

Natural England Sites of Special Scientific Interest

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2 SITE SETTING

2.1 Location

The proposed development is located some 250 m south of the village of Upper Benefield, East Northamptonshire. The site is centred on National Grid Reference (NGR) SP 979 887 and its location is shown on Figure 1.

The proposed site is bounded by agricultural land in all directions, comprising both arable and grazing.

2.2 Landform

The proposed development is located in an area of low rolling relief comprising shallow east- west trending valleys. Elevations decrease from a local high of 103 metres Above Ordnance Datum (mAOD) 2.5 km east of the site to 40 mAOD 2.5 km southeast (Figure 1).

Elevations across the Application Area decrease from 80 mAOD southeastwards to the base of a small east-west trending valley at 65 mAOD. Elevations within the valley continue to gradually decrease eastwards. To the north of the Application Area, elevations increase to 90 mAOD in the village of Upper Benefield (Figure 1).

2.3 Hydrology

The hydrology of the site and its environs has been derived from Ordnance Survey maps, a water features survey and data from the Environment Agency.

The locations of the water features discussed in this section are shown on Figure 1.

2.3.1 Watercourses The site is located in the catchment of the River Nene which is characterised by eastwardly flowing tributaries. Three such tributaries are located within 3 km of the Application Area: one (unnamed) adjacent to the southern boundary, one (unnamed) 800 m to the north and the last (the Lyveden Dyke) 2.5 km to the southeast.

The small watercourse adjacent to the southern site boundary (Ref 1, Figure 1) flows eastwards and becomes Glapthorn Brook (Photographs 1 and 2) before discharging to the River Nene north of Oundle, some 7.5 km east-northeast of the Application Area. This watercourse, which shall be referred to as Glapthorn Brook, rises some 4 km west of the site (NGR SP 9395 8905) and six tributaries, rising from the valley sides, contribute to flow along its course. Some 200 m upstream of the Application Area Glapthorn Brook drains to ground at a sinkhole (NGR SP 937 883) and is below ground level between this point and the southwestern corner of the Application Area. It is not known whether this reach is culverted or if water flows through fractures (high permeability pathways).

During a site visit on 6th March 2012, flow to the sinkhole was observed from a northwards flowing tributary (Ref 2, Figure 1), which had been recently maintained and cleared. Flow within the tributary was estimated at a rate of some 0.5-1 l/s (Photograph 3). Water pooled in an area measuring some 2 m x 15 m in the base of the watercourse, where it seeped to ground. The rest of the tributaries of Glapthorn Brook between the Application Area and Lower Benefield were dry at the time of the site visit (6th March 2012).

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The small watercourse located in the valley 800 m north of the site and 500 m north of Upper Benefield flows northeastwards to its confluence with the River Nene some 2 km north of Cotterstock.

Lyveden Dyke (Ref 3, Figure 1), is located in the adjacent valley located 2.5 km to the southeast of the site and flows northeastwards to the River Nene, south of Oundle.

2.3.2 Springs and wells One spring and two wells, shown on OS Explorer Map 224, are located within 2 km of the Application Area. The spring is located adjacent to a footbridge over Glapthorn Brook (NGR SP 984 887), some 250 m northeast of the southeastern boundary. A 200 mm culvert pipe is located above the point at which seepage from ground was observed (6th March 2012, Photographs 4 and 5).

Flow was not observed from the culvert, only seepage from below the structure occurred at an estimated rate of <0.5 l/s. Downstream of this spring, flow was observed in Glapthorn Brook, albeit at <1 l/s. Immediately upstream of the spring the brook was dry (6th March 2012).

Wells are indicated at Stocks Hill (NGR TL 996 886) some 1.5 km east and Grange Farm located 1.5 km northwest of the Application Area respectively.

2.3.3 Ponds and waterbodies Three small private ponds are located in Upper Benefield, however these are not believed to be groundwater-supported (pers comms Major Watts-Russell, the landowner).

Two waterbodies are indicated at NGR TL 977 880, these are located on the opposite side of the valley to the Application Area at elevations of between 80 and 85 mAOD, ie similar or higher in elevation than the Application Area. It was not possible to access these waterbodies during the site visit, however they are believed to comprise historical sludge pits (pers comms Major Watts-Russell), which are no longer in use. Aerial photographs (Google earth) indicate the pits have had a thick vegetation cover since at least 2004. With consideration of their designed function the pits are assumed to be perched above the groundwater level.

2.3.4 Rainfall Long-term average (LTA) rainfall data was obtained from the Warmington rain gauging station located 10 km north-northeast of the Application Area (NGR TL 08088 91212).

Monthly averages are shown in Table 2.3.4. The mean LTA annual rainfall is 601 mm.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 47 39 37 48 44 44 56 60 57 59 59 51 Table 2.3.4: Long-term average rainfall (mm)

2.3.5 Surface water abstractions Data provided by the Environment Agency and Peterborough County Council indicated that there are no current licensed or unlicensed abstractions within 2 km of the Application Area.

2.3.6 Source Protection Zones (SPZs) The Application Area is not located within a Source Protection Zone, as designated by the Environment Agency.

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2.3.7 Ecologically protected sites Two Sites of Special Scientific Interest (SSSI) are located within 2 km of the Application Area, citations are provided in Appendix 1. The closest is Spring Wood (SSSI) located 600 m to the southwest and the other is Banhaw Wood, located 850 m southeast. Both woods comprise semi-natural broadleaved woodland which forms remnants of the ancient Royal Forest of Rockingham. The vegetation conforms to the wet ash-maple woodland type and comprises Ash (Fraxinus excelsior), oak (Quercus robur) and field maple (Acer campestre). Ground flora is rich and comprises dog’s mercury (Mercurialias perennis) and bluebell (Hyacinthoides non-scripta).

2.4 Geology

2.4.1 Regional Solid The regional solid geology comprises a sequence of easterly and southerly gently dipping strata of age (Figure 2). The stratigraphic sequence of the solid geology, taken from BGS Sheet 171, is given below:

Period Formation Thickness (m) Oxford Clay Up to 29 Kellaway Formation 5 – 8 Cornbrash Formation 0.3 – 3 Blisworth Clay Formation 3 – 6 Great Blisworth Limestone Formation 4 – 8 Middle Oolite Jurassic Group Rutland Formation (inc. Wellingborough 5 - 14 Limestone member) UNCONFORMITY Inferior Lincolnshire Limestone Formation 0 – 12 Oolite Grantham Formation 0 – 8 Group Northampton Sand Formation 0 – 8 Table 2.4.1: Stratigraphic sequence of solid geology

Outcrops of the solid strata are primarily located along the immediate catchment of major watercourses in the region, namely the River Nene and associated tributaries.

All strata were deposited in a marine environment resulting in thick mudstones separated by thin, often complex, sequences of , mudstones and sands.

As a result of a very gentle, regional, easterly dip, the older strata outcrop in the west and the younger in the east. The oldest outcrops comprise large exposures of Northampton Sands to the northeast of Corby. These are overlain by the mudstones and limestones representative of the Inferior Oolite and Great Oolite groups, Cornbrash Formation and Kellaway Formation. The youngest solid strata in the region is represented by the Oxford Clay, which covers a significant area in the east of the region.

An unconformity separates the top of the Inferior Oolite Group, marked by the Lincolnshire Limestone Formation, and the base of the represented by the Rutland Formation.

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A number of normal faults are present in the southwest of the region, these have a WNW-ESE orientation.

Of regional economic importance is the Northampton Sand Formation, which is locally known as Ironstone. This has been extensively quarried over large areas north of Kettering and east of Corby. The Blisworth Limestone Formation has also been locally quarried on a much smaller scale towards the east of the region on exposed strata along the Nene Valley.

Superficial The majority of the region is covered by Quaternary glacial deposits which can be categorised into Till, glaciofluvial sand and gravel, Terrace Deposits or Alluvium. The Alluvium and Terrace Deposits are associated with the courses of the major rivers in the region and their tributaries. Stony and sandy clay Till forms extensive outcrops over much of the region. Glaciofluvial sand and gravel deposits occur sporadically located at the margins of the Till and are likely to underlie the Till over greater extents. Outcrops of sand and gravels are located southwest of Corby. River Terrace Deposits present along the floodplain of the River Nene are shown on the geology map as worked and/or backfilled.

2.4.2 Local geology The local geology had been derived from BGS map 171, drilling logs of boreholes drilled within the Application Area (supplied by BGS) and observations made at site. The logs of the boreholes are provided in Appendix 2 and their locations shown on Figure 3.

The site is located on the south facing side of a shallow valley, with youngest strata, Oxford Clay, exposed north of the Application Area, Cornbrash across the centre and Blisworth Clay and Blisworth Limestone to the south. Exposures of Blisworth Limestone also extend eastwards along the base of the valley.

The Blisworth Limestone Formation, the economic mineral at the site, is up to 5.7 m thick as indicated by BH UB08/10 (Appendix 2 and Figure 3). This is underlain by the Rutland Formation which comprises grey and green clays with intermittent beds of limestone (the Wellingborough Limestone member).

The Blisworth Limestone Formation is overlain by the Blisworth Clay Formation identified on the BGS map as outcropping within the southern half of the Application Area. Data from borehole logs drilled within the site indicate that the thickness of Blisworth Clay increases southwards across the Application Area from 3.6 m (UB01/10P) to 4.7 m (UB08/10).

Cornbrash, which overlies the Blisworth Clay, was only identified in UB01/10P in the northeast of the site at 1.5 m below ground level (mbgl), or where it had a thickness of 1.5 m, but was not detailed on driller’s logs in boreholes to the south. Clasts of yellow, friable limestone (Cornbrash) were observed to comprise a notable percentage (~1-5+%) of the topsoil composition in the central Application Area (Photograph 6).

Inferred contours of the top and base of the Blisworth Limestone Formations (Figures 4a and 4b) indicated a local gradient of some 0.01 to the east, south and west, and approximately equivalent to the topographic contours.

Outcrops of glaciofluvial sand and gravel are indicated (BGS map 171) to be located 1.5 km northeast of the Application Area. Extensive deposits of Boulder Clay are indicated to the north, west and northeast of the Application Area and on the north facing slope on the opposite side of the valley.

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Clay was observed in the upper 2.4 to 6 m in all the boreholes. This was attributed to Boulder Clay in boreholes UB01/10P and UB02/10P in the northeast. No classification was given to the clay covering the remainder of the site, hence it could be attributed to the Blisworth Clay.

2.5 Hydrogeology

2.5.1 Aquifer status and regional context The solid strata locally comprise low permeability mudstones and siltstones, with the exceptions of the Lincolnshire Limestones, Blisworth Limestone Formation and Cornbrash and some thin sand bands. Of these the only formations in the area of sufficient thickness and respective aquifer properties to be classified as aquifers are the Blisworth Limestone Formation (a Principal Aquifer) and the Cornbrash (a Secondary Aquifer, Figure 5).

2.5.2 Groundwater abstractions Data provided by the Environment Agency shows that there are no current licensed abstractions within 3 km of the centre of the Application Area (NGR SP 979 888).

East Northamptonshire Council provided details of two private water supplies which are located between 2 km and 2.5 km from the Application boundary. These are detailed in Table 2.5.2 and shown on Figure 1.

Ref No NGR (TL) Name Source Current status 1 00299 87699 Churchfield Farm Borehole In use 2 00299 87699 Churchfield Cottages Borehole In use Table 2.5.2: Private water supply details

Although detailed as two supplies, one borehole supplies both properties.

2.5.3 Aquifer characteristics Superficial deposits Regardless of origin of the observed clay overburden (Boulder Clay or Blisworth Clay) similar hydraulic properties are anticipated for the clay across the Application Area whereby it forms a low permeability layer above the more permeable limestones.

Solid The Great Oolite Limestone of Lincolnshire, the Cotswolds and Somerset comprises a thick sequence of fractured limestone. However, in the Midlands the Great Oolite sequence, of which the Blisworth Limestone Formation is a member, contains a higher proportion of clays and shales which reduce its water-bearing properties. Where groundwater does occur, flow is likely to be controlled by fractures, fissures and bedding planes.

2.5.4 Groundwater level and distribution Groundwater level data has been collected within the site since installation of piezometers in September 2010. Data is presented in Appendix 3 and as a hydrograph on Figure 6. Details of the piezometer installations indicate that all piezometers sample the Blisworth Limestone.

Groundwater elevations within the Application Area (September 2010 to March 2012) ranged between 62.51 mAOD and 67.13 mAOD (UB02/10P, February 2011).

Groundwater level hydrographs for boreholes UB04/10P and UB05/10P located west of the site show little variation over the whole monitoring period, with a range of 0.35 m and 0.19 m

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The very small variation in groundwater levels and the perceived low response to rainfall in UB04/10P and UB05/10P could indicate that fissures and fractures within the rock were not intercepted in these boreholes. Alternatively, this may result from clay ‘smearing’ during installation of the piezometers, sealing fissures adjacent to the piezometer.

Conversely the large range observed in UB02/10P (4.33 m) suggests rock is more responsive to rainfall in this part of the Application Area, hence better hydraulic connectivity between fractures.

Responses in UB01/10P demonstrate similarities to both UB02/10P and those to the west of the site (UB04/10P and UB05/10P), ie some seasonal variation but a muted response to rainfall. Between July and December 2011 groundwater levels were the lowest recorded on-site, however still remained a minimum of 1.75 m above the base of the Blisworth Limestone (UB01/10P) and up to 3.17 m above the base in UB05/10P (September 2010 to March 2012).

Based on groundwater level data and borehole logs the saturated thickness of mineral ranges from 1.75 m to 6 m across the Application Area, with a mean of 3.7 m.

The inferred groundwater flow direction based on groundwater level data is very variable, from northwestwards to northeastwards to southwestwards during the monitoring period. Based on this and the varied response to rainfall recharge, it is considered that the installed piezometers measure isolated ‘pockets’ of groundwater within the Blisworth Limestone Formation and that a overall groundwater flow direction cannot be derived. Based on the base elevation of the Blisworth Limestone Formation it could be expected that groundwater flow would be southward towards Glapthorn Brook adjacent to the southern boundary.

The observed sinkhole southwest of the site and dry reach of the watercourse along the southern site boundary, indicate that groundwater levels within the Blisworth Limestone are below ground level adjacent to the watercourse.

A comparison of groundwater level and rainfall data was made (Environment Agency Warmington Station). Results indicate a direct relationship between rainfall and groundwater level was not observed in any of the piezometers (Figure 6).

2.5.5 Hydraulic conductivity Limestones commonly have a low effective porosity which refers to a low proportion of interconnected pore spaces. This characteristic should result in a low permeability rock, however significant fractures along which water flows are characteristic of limestones.

In order to estimate the hydraulic conductivity within the Application Area, in-situ permeability tests were undertaken at boreholes UB02/10P and UB05/10P in the east and west of the site respectively (6th March 2012). The results are compared with expected values based on accepted tests1.

Analysis of the data collected from falling and rising head tests indicated a range in hydraulic conductivity of between 0.02 m/d and 2.2 m/d with a mean of 0.7 m/d (Appendix 4). These results are within the expected range.

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The Blisworth Clay which overlies the Blisworth Limestone and the Rutland Formation which underlies the limestone both comprise clay which would be expected to have a lower hydraulic conductivity of between 9 x 10-2 m/d and 10-4 m/d.

2.5.6 Baseline groundwater quality No groundwater quality data was available for this site.

2.6 Conceptual hydrogeological model

A conceptual understanding of the hydrogeological regime for the Application Area has been derived from field data and published sources.

It is proposed to extract mineral from the Blisworth Limestone Formation.

The Blisworth Limestone is around 5.7 m thick at the site. It is underlain by clays of the Rutland Formation and overlain by the Blisworth Clay Formation. There are local variations, however the limestone generally dips gently to the southeast.

The Blisworth Limestone is classified by the Environment Agency as a Principal Aquifer. Groundwater level data indicate that the water level is within the limestone (an unconfined aquifer). It appears that groundwater is contained in localised high permeability lenses which are poorly connected across the formation and therefore a single watertable may not exist. Consequently, groundwater flow direction appears highly variable.

The estimated saturated thickness of the Blisworth Limestone aquifer is 1.8 to 6 m based on existing monitoring data.

The Blisworth Clay Formation forms an effective low permeability base to the Blisworth Limestone Formation. The overlying clays of the Rutland Formation prevent rapid recharge of groundwater in the underlying limestone from rainfall.

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3 PROPOSED DEVELOPMENT

3.1 Overview

The Application Area extends to 9.88 Ha, however the proposed area for mineral only extends to 2.32 Ha and is located in the centre of the proposed site (Figure 7).

It is intended to extract mineral using a hydraulic excavator in a series of 5 cuts measuring some 30-40 m wide and approximately 150 m long (Figure 7). The first cut will be located in the east of the site with successive cuts progressing westwards. It is estimated that extraction will be undertaken over a period of up to 17 years.

Working of each cut will be northwards, once screening bunds have been completed overburden will be used to backfill the previous cut. Waste stone will be used to backfill the voids and overburden material placed above this. Restoration will therefore occur progressively throughout the development.

The total recoverable limestone is calculated at 75,400 m3 or 169,650 tonnes. It is anticipated that stone of masonry quality comprises some 40% of this.

The site will be worked seasonally over an estimated 6 months per year.

3.2 Water management

Groundwater level data indicates the saturated thickness of mineral ranges 1.7 m to 6 m with an annual mean of 3.7 m. It is therefore considered that groundwater will be encountered during working and will require management.

It is proposed to pump water which collects in each cut to a settlement lagoon which will be constructed in the south of the site (Figure 7).

Water from the settlement lagoon will be discharged, in a controlled manner, to Watercourse 1 adjacent to the southern boundary.

3.2.1 Radius of influence of dewatering Calculations have been undertaken to quantify the groundwater inflow volumes and thereby allow assessment of the potential impacts of dewatering upon the extant water environment (Appendix 5).

An indication of the radius of influence associated with dewatering has been calculated using an approximation method detailed in “Control of groundwater for temporary works” (SH Somerville, 1986, prepared on behalf of the Construction Industry Research and Information Association (CIRIA) Report 113). The method relates the radius of influence of drawdown to hydraulic conductivity:

ri = 3000 h√(k)

Where: ri = radius of influence of dewatering (m) h = dewatering depth (m) k = hydraulic conductivity (m/d)

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Hydraulic conductivity (m/d) Radius of influence (m) 0.02 5 1 38 5 84 Table 3.2.1: Radius of influence

For the range of hydraulic conductivities (0.02 to 5 m/d) the radius of influence is calculated at between 5 and 84 m from the edge of the quarry void using the mean saturated thickness of 3.7 m.

3.2.2 Discharge requirements Water derived from both groundwater ingress and rainfall will enter the workings and require discharging off-site. An estimate has been made of the potential volumes of water generated, as discussed below.

The groundwater inflow from the limestone at the maximum extent of the development has been estimated using the Thiem formula. The calculations are shown in Appendix 5.

The Thiem formula approximates the quarry void to a large diameter well installed within an unconfined aquifer. Groundwater inflow to the quarry was calculated based on a range of hydraulic conductivities of 0.02 m/d, 1 m/d and 5 m/d and a saturated thickness of 3.7 m.

For the observed bulk hydraulic conductivities of the limestone the estimated groundwater inflow would be between 0.1-2.3 l/s for each cut.

3.2.3 Rainfall/run-off The mean annual rainfall in the vicinity of the Application Area is about 601 mm. Assuming 100% of rainfall reaches the quarry floor the mean daily inflow to each cut from rainfall is 10 m3/d, this equates to a continuous flow of 0.1 l/s.

Therefore the total combined volume of water requiring pumping and discharge from each cut is some 15-200 m3/d and is most likely in the region 78 m3/d, based on a hydraulic conductivity of 1 m/d.

Plans indicate the maximum extent of working would require 2 cuts operation at any one time, therefore the maximum volume of water requiring management is 155 m3/d or a conservative estimate of 400 m3/d.

3.3 Restoration

Each cut will be progressively restored to agriculture using overburden and waste rock from workings. It is not proposed to import material from off-site, therefore the restoration profiles are expected to be lower than original ground levels following extraction.

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4 ASSESSMENT OF IMPACTS and MITIGATION MEASURES

An assessment of the potential effects of the proposed mineral extraction on the water environment within the Application Area and its environs has been undertaken.

The methodology used for the assessment is presented in Appendix 6.

4.1 Catchment sensitivity

In order to assess the magnitude and significance of effect of potential impacts the catchment sensitivity must initially be assessed.

The Application Area is located within both a Principal Aquifer (Blisworth Limestone) and a Secondary Aquifer (Cornbrash). Therefore the catchment of would be considered ‘medium’ to ‘high’ sensitivity. However, data provided by the Environment Agency and local authorities indicates that there are no licensed groundwater or surface water abstractions within 3 km of the Application Area and the two identified unlicensed abstractions are at a distance of 2 and 2.5 km southeast of the site. These data indicate that locally the aquifers are less sensitive.

In addition, it is estimated that dewatering will be required, however the calculated volumes are low (<200 m3/d).

The watercourse adjacent to the southern boundary is ephemeral and dry for significant periods of the year and is of low ecological importance.

Two Sites of Special Scientific Interest (SSSI) are located within a 2 km radius of the Application Area. Spring Wood (SSSI) is some 600 m to the southwest and up-gradient of the Application Area. Banhaw Wood (SSSI) is located in an adjacent valley to the southeast. As neither of the two sites are down-gradient of the proposed development their potential sensitivity to influence from the proposed workings is low.

Based on the above context the baseline catchment sensitivity of Stonepits Quarry is considered to be ‘medium’.

4.2 Water quality

4.2.1 Hydrocarbons Assessment During mineral extraction potential exists for pollution to occur from spillage of fuel or lubricants. In the unlikely occurrence of such an event contaminants may seep directly to the watertable or reach a local watercourse. The magnitude of impact may be greater within the quarry void due to the removal of a section of the unsaturated zone. Due to the small scale of operations, and the proposed periodic working of the site, the likelihood of a spillage occurring is relatively low. Therefore the magnitude of impact has been assessed as ‘medium’ and significance of effect as ‘moderate’.

Mitigation measures Fuels will be required for plant (excavator, dump truck, compressor and generator) and will be stored in a bunded tank. Strict refuelling procedures will be imposed and all plant will undergo regular maintenance and servicing, conducted on areas of hardstanding and according to best practice.

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In the unlikely event of a hydrocarbon spillage, discharge of water generated from dewatering would cease immediately. The contaminant source will be identified and further spillage prevented. The spill will be contained and managed and the resultant materials disposed of in accordance with current best practice. A spill kit will be kept on site for use in such an event.

The residual impacts to surface water and groundwater quality of a hydrocarbon spillage are therefore assessed as ‘low’.

4.2.2 Suspended solids Assessment – Discharge water Water pumped from the quarry void and discharged to the Glapthorn Brook may contain suspended solids, the impact of this water if discharged untreated is considered to be ‘medium’ and the significance of effect as ‘moderate’.

Mitigation Measures Discharge of water off-site will require an Environmental Permit. Water quality will be monitored regularly to ensure conditions within the Environmental Permit were met.

Prior to discharge off-site water will flow through a settlement lagoon. The lagoon will be sized to ensure that sufficient settlement occurs and therefore the required discharge water quality standards are met.

The settlement lagoon will provide additional means of containing any contaminants in the unlikely occurrence of spillage or leakage. If such an event occurred discharge would cease immediately and only resume when water was of the required standard.

The residual impact is assessed as ’insignificant’.

Assessment – Access road run-off The access road will be constructed from waste stone generated within the site. The proposed location of the access road is adjacent to the watercourse hence there is potential for suspended solids to run-off into the watercourse during rainfall events. The watercourse is ephemeral and of low ecological value with no known associated abstractions, therefore the impact is assessed as ‘medium’.

Mitigation Measures During construction of the access road, consideration should be given to minimising discharge to the watercourse from the construction area. This will be achieved through adherence to best practice as detailed in Pollution Prevention Guidelines 5 (PPG5) – Works and maintenance in or near water.

The residual impact is assessed as ‘low’.

4.3 Groundwater levels

Based on the conservative hydraulic conductivity of 5 m/d the predicted maximum lateral extent of drawdown associated with dewatering is 84 m, which would not extend beyond the proposed Application boundary. The potential impact to the surrounding environment and water- supported features from the estimated drawdown is ‘negligible’. Therefore mitigation measures are not proposed.

4.3.1 Groundwater flow and surface water flow Assessment

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

Due to the low hydraulic connectivity within the limestone a definitive groundwater flow direction was not identified. However, it is considered most likely that generally groundwater flow in the vicinity of the Application Area would be southwards to southeastwards towards the watercourse.

Water pumped from the quarry void will be discharged to the watercourses following settlement. Therefore a reduction in flow to the watercourse as a result of working will not be realised. It is understood that the watercourse is ‘dry’ for significant periods of the year, therefore controlled discharge from the site would help maintain a better flow in the adjacent reach and is considered to have a positive impact.

The potential recharge to the Blisworth Limestone during working will be increased by the temporary removal of the overburden. Rainfall infiltrating to groundwater is likely to flow down- gradient and accumulate in the southern end of the void where it will be pumped to the settlement lagoon. The magnitude of the potential impact on recharge is assessed as ‘negligible’ with a significance of ‘minor’ and additional mitigation measures are not proposed.

4.4 Groundwater and surface water abstractions

Groundwater or surface water abstractions were not identified within 2 km of the Application Area. Therefore the magnitude of potential impact is assessed as ‘negligible’ with a significance of ‘minor’.

4.5 Springs

The nearest spring is located 200 m east of the Application Area. It is highly unlikely that the cone of depression from dewatering will extend to impact on the source of the spring, therefore the magnitude of the potential impact is assessed as ‘low’ with significance of effect of ‘minor’.

However, any impacts would be mitigated by controlled discharge from the settlement lagoon to the Glapthorn Brook which is the same watercourse into which the spring flows. The residual impact is assessed as ‘insignificant’ and additional mitigation measures are not proposed.

4.6 Ecologically protected sites

Spring Wood SSSI is located upstream of the Application Area, about 800 m southwest of the site, therefore the potential impacts from surface water quality incidents are ‘negligible’.

The maximum extent of the calculated cone of depression does not extend beyond the Application boundary, therefore the potential impacts on Spring Wood (SSSI) from dewatering is also ‘negligible’.

Banhaw Wood (SSSI) is located in the adjacent valley 1 km southeast of the site and it is also considered that potential impacts on it would be ‘negligible’.

4.7 Post-operational impacts

The limestone removed during extraction will be replaced with waste stone and overburden. It is understood that waste limestone will be used to backfill the void and overburden placed on top. The hydraulic conductivity within the limestone waste will potentially be higher than the virgin rock, as would be the water storage potential.

Emplacement of overburden will provide a capping layer over the waste rock therefore the recharge potential of the aquifer will not be significantly different from the pre-operational status. Page 13 May 2012 Z:\JOBS\JOBS\P002 PGR\P002-4 Benefield Quarry\P002-04 Incoming Data\P002-04 Consultants\Hafren Water\Hydro

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

The potential impact of proposed restorations is considered ‘negligible’.

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

5 CUMULATIVE IMPACTS

Cumulative impacts have been assessed with respect to groundwater quality, surface water quality, flood risk and site restoration. Such impacts are those which result from changes caused by past, present or future actions and can be defined under two categories:

Incremental impact – when one impact occurs at the same time as another from a separate development

Combined impact – relates to impacts caused by the development on a particular location

The nearest quarry understood to be actively dewatering is located beyond 2 km beyond the Application Area. Therefore it is considered there is not an incremental impact to the groundwater or surface water discharge.

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

6 SUMMARY AND CONCLUSIONS

6.1 Churchfield Stone Ltd is seeking permission to extract Blisworth Limestone at a greenfield site, referred to as Stonepits Quarry, located near to Upper Benefield, East Northamptonshire.

6.2 The site is located in the catchment of the River Nene which is characterised by eastwardly flowing tributaries. A small watercourse flows eastwards adjacent to the southern boundary of the proposed development, this watercourse is ephemeral and is know to be dry for significant periods.

6.3 The regional solid geology comprises a sequence of easterly and southerly gently dipping strata of Middle Jurassic age. The site is located on the south facing side of a shallow valley with youngest strata, Oxford Clay, exposed in the north of the Application Area, Cornbrash across the centre and Blisworth Clay and Blisworth Limestone in the south. Exposures of Blisworth Limestone also extend eastwards along the base of the valley.

6.4 The Blisworth Limestone Formation, the economic mineral at the site, is up to 5.7 m thick, and is overlain by the Blisworth Clay Formation. The Blisworth Limestone Formation is designated as a Principal Aquifer.

6.5 Groundwater monitoring data collected within the site indicates that the groundwater table is located within the Blisworth Limestone. Analysis of the monitoring data shows two distinctly different hydraulic characteristics across the Application Area. The observed groundwater level range in piezometers located in the west of the site is very small at <0.37 m compared to that in the east at between 2.76 m to 4.33 m. It is concluded that very limited hydraulic connectivity extends across the Application Area, therefore a single watertable cannot be assumed.

6.6 Based on these data the saturated thickness of mineral ranges from 1.75 m to 6 m across the Application Area, with a mean of 3.7 m. It is therefore considered that groundwater will be encountered during working and will require management.

6.7 In-situ permeability tests were undertaken in the east and west of the site respectively. The results indicated a range in hydraulic conductivity of between 0.02 m/d and 2.2 m/d and a mean of 0.7 m/d.

6.8 The maximum calculated extent for the cone of depression is 84 m from the edge of the void, which would not extend beyond the Application boundary, therefore potential impacts from dewatering would be negligible.

6.9 The estimated discharge from dewatering each cut is between 15-200 m3/d and is most likely in the region 78 m3/d, based on a hydraulic conductivity of 1 m/d.

6.10 Prior to discharge off-site water will flow through a settlement lagoon. The lagoon would be sized to ensure that sufficient settlement occurred and therefore the required water quality standards could be met.

6.11 During mineral extraction potential exists for pollution to occur from spillage of fuel or lubricants. Fuels required for plant (excavator, dump truck, compressor and generator) will be stored in a bunded tank. Strict refuelling procedures would be imposed and all plant would undergo regular maintenance and servicing, conducted on areas of hardstanding and according to best practice. The residual impacts of a hydrocarbon spillage to surface water and groundwater quality are therefore assessed as ‘low’. Page 16 May 2012 Z:\JOBS\JOBS\P002 PGR\P002-4 Benefield Quarry\P002-04 Incoming Data\P002-04 Consultants\Hafren Water\Hydro

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

6.12 Licensed surface water and groundwater abstractions are not located within a 2 km radius of the Application Area. However, two private water supplies are located between 2 and 2.5 km southeast of the site, which are considered to be beyond the potential impacts.

6.13 During construction of the access road consideration should be given to minimising discharge to the watercourse from the construction area. This will be achieved through adherence to best practice as detailed in Pollution Prevention Guidelines 5 (PPG5) – Works and maintenance in or near water.

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

FIGURES

May 2012

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Application Area Well / spring Private water supply

290000

Well Glapthorn Brook

289000 Footbridge Spring

1

Well

2

Sinkhole 288000

Reproduced from OS Explorer map 224 1:25,000 scale by 3 permission of Ordnance Survey on behalf of The Controller of Her Majesty’s Stationary Office. © Crown copyright. All rights Lyvedon Dyke reserved. Licence number WL9705. 287000 495000 496000 497000 498000 499000 500000 Client: Title: Barkers Chambers, Barker Street, Shrewsbury, Churchfield Stone Ltd Shropshire, UK, SY1 1SB Site location and water features 6 The Old Quarry Project: Date: Tel: 01743 355770 Nene Valley Business Park, Oundle Stonepit Quarry, Benefield Mar-2012 PETERBOROUGH, PE8 4HN Figure: Scale: Fax: 01743 357771 1 1:25,000 I:\Stonepit Quarry, Benefield\Figures\1 - Location Site location

292000

290000

Application Area

289000

Reproduced from BGS Maps 171 1:50,000 288000 scale by permission of British Geological Survey on behalf of The Controller of Her Majesty’s Stationary Office. © Crown copyright. All rights reserved. Licence number WL9705.

Client: Churchfield Stone Ltd 286000 6 The Old Quarry Nene Valley Business Park, Oundle PETERBOROUGH, PE8 4HN Title:

492000 494000 496000 498000 500000 502000 Geology Project: Stonepit Quarry, Benefield Figure: 2 Date: Scale: Mar-2012 1:25,000 Barkers Chambers, Barker St, Shrewsbury, UK, SY1 1SB Tel. 01743 355770 Fax. 01743 357771 Client: Churchfield Stone Ltd 6 The Old Quarry Nene Valley Business Park, Oundle PETERBOROUGH, PE8 4HN Title: Borehole and trial pit locations Project: Stonepit Quarry, Benefield Figure: 3 Date: Scale: Mar-2012 1:2,500 @ A3 Barkers Chambers, Barker St, Shrewsbury, UK, SY1 1SB Tel. 01743 355770 Source: PGW&A LLP (Drawing No. BENE 1B(A)) Fax. 01743 357771 Client: Churchfield Stone Ltd 6 The Old Quarry Nene Valley Business Park, Oundle PETERBOROUGH, PE8 4HN Title: Inferred contours on top of limestone Project: Stonepit Quarry, Benefield Figure: 4a Date: Scale: Mar-2012 1:2,500 @ A3 Barkers Chambers, Barker St, Shrewsbury, UK, SY1 1SB Tel. 01743 355770 Source: PGW&A LLP (Drawing No. BENE 4A) Fax. 01743 357771 Client: Churchfield Stone Ltd 6 The Old Quarry Nene Valley Business Park, Oundle PETERBOROUGH, PE8 4HN Title: Inferred contours on base of limestone Project: Stonepit Quarry, Benefield Figure: 4b Date: Scale: Mar-2012 1:2,500 @ A3 Barkers Chambers, Barker St, Shrewsbury, UK, SY1 1SB Tel. 01743 355770 Source: PGW&A LLP (Drawing No. BENE 3A) Fax. 01743 357771 Site location

1 km

Client: Title: Barkers Chambers, Barker Street, Shrewsbury, Churchfield Stone Ltd Shropshire, UK, SY1 1SB Bedrock aquifer designation 6 The Old Quarry Project: Date: Tel: 01743 355770 Nene Valley Business Park, Oundle Stonepit Quarry, Benefield Mar-2012 PETERBOROUGH, PE8 4HN Figure: Scale: Fax: 01743 357771 5 as shown @ A4 I:\Stonepit Quarry, Benefield\Figures\5 - Aquifer designations 150 70

140 69

130 68

120 67 Significant rainfall 110 event on 4th March 66

100 65

90 64

80 63

70 62 Monthly Monthly rainfall (mm) Monthly Monthly rainfall (mm) 60 61 Groundwater Groundwater level (mAOD) 50 60 Groundwater level (mAOD)

40 Rainfall 59 BH1/10 30 58 BH2/10 20 57 BH4/10 10 56 BH5/10 0 55 Sep-10 Nov-10 Jan-11 Mar-11 May-11 Jul-11 Sep-11 Nov-11 Jan-12 Mar-12 Date

Client: Title: Barkers Chambers, Barker Street, Shrewsbury, Churchfield Stone Ltd Shropshire, UK, SY1 1SB Hydrographs 6 The Old Quarry Project: Date: Tel: 01743 355770 Nene Valley Business Park, Oundle Stonepit Quarry, Benefield Mar-2012 PETERBOROUGH, PE8 4HN Figure: Scale: Fax: 01743 357771 6 n/a I:\Stonepit Quarry, Benefield\Data\Groundwater levels Client: Churchfield Stone Ltd 6 The Old Quarry Nene Valley Business Park, Oundle PETERBOROUGH, PE8 4HN Title: Phasing plans Project: Stonepit Quarry, Benefield Figure: 7 Date: Scale: Mar-2012 1:2,500 @ A3 Barkers Chambers, Barker St, Shrewsbury, UK, SY1 1SB Tel. 01743 355770 Source: PGW&A LLP (Drawing No. BENE 5©) Fax. 01743 357771 Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

PHOTOSHEETS

May 2012

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Photograph 1: Dry watercourse to south of site Photograph 2: Dry watercourse to south of site

Photograph 3: Tributary and sinkhole Photograph 4: Spring adjacent to footbridge

Client: Churchfield Stone Ltd Title: Barkers Chambers, Barker Street, Shrewsbury, Photosheet 1 Shropshire, SY1 1SB Stonepits Quarry, Benefield Tel: 01743 355770 OUNDLE Project: Stonepit Quarry Date: May-2012 Fax: 01743 357771 PE8 5AN P:\Projects\Stonepit Quarry, Benefield\Figures\Photosheets Photograph 5: Water observed downstream of spring Photograph 6: Cornbrash with soil, looking northeast across Application Area

Client: Churchfield Stone Ltd Title: Barkers Chambers, Barker Street, Shrewsbury, Photosheet 2 Shropshire, SY1 1SB Stonepits Quarry, Benefield Tel: 01743 355770 OUNDLE Project: Stonepit Quarry Date: May-2012 Fax: 01743 357771 PE8 5AN P:\Projects\Stonepit Quarry, Benefield\Figures\Photosheets Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

APPENDIX 1

SSSI citation

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COUNTY: NORTHAMPTONSHIRE SITE NAME: BANHAW, SPRING & BLACKTHORNS WOODS

District: East Northamptonshire

Status: Site of Special Scientific Interest (SSSI) notified under Section 28 of the Wildlife and Countryside Act 1981

Local Planning Authority: East Northamptonshire District Council

National Grid Reference: SP 988876 SP 967881 SP 952880

Ordnance Survey Sheet 1:50,000: 141 1:10,000: SP 98 NE

Date Notified (Under 1949 Act): Date of Last Revision:

Date Notified (Under 1981 Act): 1986 Date of Last Revision:

Area: 125.6 ha 310.4 ac

Other Information: This is a new site.

Description and Reasons for Notification

Banhaw, Spring and Blackthorns Woods consist of three neighbouring blocks of semi-natural broadleaved woodland which together form one of the largest remnants of the ancient Royal Forest of Rockingham. The vegetation conforms to the wet ash-maple woodland type with a coppice and standards structure, overlying calcareous clay soils.

Ash Fraxinus excelsior both as standards and regrowth from old coppice, forms the main component of the canopy in both woods with pendunculate oak Quercus robur occurring infrequently. There is a strong secondary element of field maple Acer campestre and in some areas silver birch Betula pendula, willows Salix spp. and crab apple Malus sylvestris are also present.

The understorey is composed of derelict coppiced field maple, ash and hawthorn Crataegus monogyna with hazel Corylus avellana, Midland hawthorn Crataegus oxyacanthoides, wild service- tree Sorbus torminalis, dogwood Cornus sanguinea and guelder rose Viburnum opulus also occurring.

The ground flora in all the woods is rich and varied with some areas dominated by dog’s mercury Mercurialis perennis and bluebell Hyacinthoides non-scripta with abundant enchanter’s-nightshade Circaea lutetiana, yellow archangel Limiastrum galeonbdolon, meadowsweet Filipendula ulmaria, wood-sorrel Oxalis acetosella and male fern Dryopteris filix-mas. Other parts of the woods support a variety of grasses, including tufted hair-grass Deschampsia cespitosa, rough meadow-grass Poa trivialis, wood millet Milium effusum and wood melick Melica uniflora. Notable woodland species occur throughout the site and include herb Paris Paris quadrifolia, sweet woodruff Galium odoratum and the orchids, early-purple Orchis mascula, common spotted Dactylorhiza fuchsii and common twayblade Listera ovata. Sanicle Sanicula europaea and greater butterfly orchid Plantanthera chlorantha are also present.

The numerous and varied rides support a good range of plants including angelica Angelica sylvestris, yellow pimpernel Lysimachia nemorum and the sedges Carex sylvatica, C. pendula, C. remota and notably C. strigosa. They provide valuable additional habitats for butterflies and other invertebrates.

Re-presentation of details approved by Council. Re-typed April 1999. Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

APPENDIX 2

Borehole logs and data

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

APPENDIX 3

Groundwater level data

May 2012

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Site: Stone Pits Benefield

BH1 BH2 BH4 BH5 Collar level (mAOD) 74.76 71.41 72.93 70.88 Ground level (mAOD) 74.26 70.87 72.44 70.37 Date mbd mAOD mbd mAOD mbd mAOD mbd mAOD 28-Sep-2010 10.33 64.43 9.17 62.24 10.13 62.80 7.87 63.01 05-Oct-2010 10.25 64.51 6.82 64.59 10.15 62.78 7.87 63.01 20-Feb-2011 11.23 63.53 4.45 66.96 9.94 62.99 7.64 63.24 27-Feb-2011 11.04 63.72 4.28 67.13 9.93 63.00 7.67 63.21 06-Mar-2011 11.12 63.64 4.38 67.03 9.96 62.97 7.68 63.20 20-Mar-2011 11.19 63.57 4.87 66.54 9.99 62.94 7.70 63.18 03-Apr-2011 11.32 63.44 5.10 66.31 9.92 63.01 7.72 63.16 05-Apr-2011 11.30 63.46 5.63 65.78 9.93 63.00 7.73 63.15 01-May-2011 11.40 63.36 5.64 65.77 9.94 62.99 7.75 63.13 10-Jun-2011 11.65 63.11 8.53 62.88 9.95 62.98 7.79 63.09 13-Jul-2011 12.10 62.66 8.59 62.82 10.20 62.73 7.82 63.06 05-Aug-2011 12.20 62.56 8.58 62.83 10.00 62.93 7.78 63.10 11-Sep-2011 12.25 62.51 8.61 62.80 10.20 62.73 7.83 63.05 21-Oct-2011 12.22 62.54 8.58 62.83 10.10 62.83 7.80 63.08 01-Nov-2011 12.20 62.56 8.58 62.83 10.00 62.93 7.74 63.14 12-Dec-2011 12.00 62.76 8.50 62.91 9.94 62.99 7.74 63.14 16-Jan-2012 11.60 63.16 8.45 62.96 9.90 63.03 7.75 63.13 17-Feb-2012 11.45 63.31 7.94 63.47 9.88 63.05 7.74 63.14 06/03/2012 9.50 65.27 6.85 64.57 9.85 63.08 7.67 63.21

Max 65.27 67.13 63.08 63.24 Min 62.51 62.80 62.73 63.05 Mean 63.24 64.50 62.95 63.14 Range 2.76 4.33 0.35 0.19 Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

APPENDIX 4

Analysis of rising and falling head tests

May 2012

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Slug Test Analysis Using Hvorslev Shape Factors

VARIABLE HEAD PERMEABILITY TEST Site : Stonepits Benefield Location : East N'hants Depth below top of casing/standpipe to : Project No : Borehole No : BH5 (a) bottom of borehole : m Date :06-Mar-2012 Sheet 1 of 1 (b) bottom of casing : m Ground Level (OD): m Contractor: (c) top of filter material : m Weather : Fine (d) center of piezometer tip : m Type of test : Test 1 - falling head permeability (e) initial ground water level : 6.4 mbd Diameter of casing/standpipe : 0.05 m Height of casing/standpipe above surface : 0.45 m Length of filter: 8.50 m Dia. of filter : 0.05 m Elevation of casing/standpipe above surface : m (OD) Type of piezometer : slotted screen L/D = 170.00 TEST RECORD Start time 12:57 Depth to Drawdown Drawdown CALCULATION: Elapsed time water (Ho) Ratio Shape Factor g See attached sheet Secs min m m (H/Ho) Cross Sectional Area A = 2.0E-03 m2 0.5 0.008 70.8 1.00 Intake Factor F = 10.66 1.0 0.017 12.4 0.18 Basic Time Lag T = 0.8 mins Taken from graph when 1.5 0.025 45.8 0.65 0.0006 days H/Ho = 0.37 2.0 0.033 32.9 0.46 K= 0.332 m/d 2.5 0.042 26.8 0.38 K= 3.84E-06 m/s 3.0 0.050 42.6 0.60 COMMENTS: 3.5 0.058 28.2 0.40 4.0 0.067 30.4 0.43 4.5 0.075 31.8 0.45 5.0 0.083 31.7 0.45 5.5 0.092 30.8 0.44 1.00 6.0 0.100 49.8 0.70 6.5 0.108 13.8 0.19 7.0 0.117 12.8 0.18 7.5 0.125 29.7 0.42 8.0 0.133 30.4 0.43 8.5 0.142 30.2 0.43 9.0 0.150 30.1 0.43 9.5 0.158 30.1 0.43 0.10

10.0 0.167 29.6 0.42 H/Ho 10.5 0.175 30.5 0.43 11.0 0.183 29.6 0.42 11.5 0.192 30.2 0.43 12.0 0.200 29.6 0.42 12.5 0.208 29.4 0.42 13.0 0.217 29.4 0.42 13.5 0.225 29.4 0.42 14.0 0.233 29.2 0.41 0.01 14.5 0.242 29 0.41 0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 15.0 0.250 29.2 0.41 Elapsed Time (minutes) 15.5 0.258 29.2 0.41 16.0 0.267 29.7 0.42 16.5 0.275 28.9 0.41

Printed: 29/05/2012 12:38 BH2 1 Falling Data Page 1 Slug Test Analysis Using Hvorslev Shape Factors

VARIABLE HEAD PERMEABILITY TEST Site : Stonepits Benefield Location : East N'hants Depth below top of casing/standpipe to : Project No : Borehole No : BH5 (a) bottom of borehole : m Date :06-Mar-2012 Sheet 1 of 1 (b) bottom of casing : m Ground Level (OD): m Contractor: (c) top of filter material : m Weather : Fine (d) center of piezometer tip : m Type of test : Test 1 - falling head permeability (e) initial ground water level : 6.4 mbd Diameter of casing/standpipe : 0.05 m Height of casing/standpipe above surface : 0.45 m Length of filter: 8.50 m Dia. of filter : 0.05 m Elevation of casing/standpipe above surface : m (OD) Type of piezometer : slotted screen L/D = 170.00 TEST RECORD Start time Depth to Drawdown Drawdown CALCULATION: Elapsed time water (Ho) Ratio Shape Factor g See attached sheet mm:ss.0 min m m (H/Ho) Cross Sectional Area A = 2.0E-03 m2 0.5 0.017 0 Intake Factor F = 10.66 1.0 0.025 0.227 Basic Time Lag T = 13.3 mins Taken from graph when H/Ho = 0.37 1.5 0.033 0.431 1.00 0.0092 days 2.0 0.042 0.463 1.07 K= 0.020 m/d 2.5 0.050 0.444 1.03 K= 2.31E-07 m/s 3.0 0.058 0.426 0.99 COMMENTS: 3.5 0.067 0.402 0.93 4.0 0.075 0.382 0.89 4.5 0.083 0.392 0.91 5.0 0.092 0.396 0.92 1.00 5.5 0.100 0.378 0.88 6.0 0.108 0.366 0.85 6.5 0.117 0.368 0.85 7.0 0.125 0.367 0.85 7.5 0.133 0.364 0.84 8.0 0.142 0.359 0.83 8.5 0.150 0.36 0.84 9.0 0.158 0.36 0.84 9.5 0.167 0.351 0.81 0.10 10.0 0.175 0.352 0.82 H/Ho 10.5 0.183 0.351 0.81 11.0 0.192 0.352 0.82 11.5 0.200 0.354 0.82 12.0 0.208 0.346 0.80 12.5 0.217 0.352 0.82 13.0 0.225 0.347 0.81 13.5 0.233 0.356 0.83 0.01 14.0 0.242 0.384 0.89 14.5 0.250 0.371 0.86 -1.000 1.000 3.000 5.000 7.000 9.000 11.000 13.000 15.000 15.0 0.258 0.368 0.85 Elapsed Time (minutes) 15.5 0.267 0.38 0.88 16.0 0.275 0.403 0.94

Printed: 29/05/2012 12:49 BH2 1 rising Data Page 1 Slug Test Analysis Using Hvorslev Shape Factors

VARIABLE HEAD PERMEABILITY TEST Site : Stonepits Benefield Location : East N'hants Depth below top of casing/standpipe to : Project No : Borehole No : BH5 (a) bottom of borehole : m Date :06-Mar-2012 Sheet 1 of 1 (b) bottom of casing : m Ground Level (OD): m Contractor: (c) top of filter material : m Weather : Fine (d) center of piezometer tip : m Type of test : Test 1 - falling head permeability (e) initial ground water level : 7.21 mbd Diameter of casing/standpipe : 0.05 m Height of casing/standpipe above surface : 0.45 m Length of filter: 11.00 m Dia. of filter : 0.05 m Elevation of casing/standpipe above surface : m (OD) Type of piezometer : slotted screen L/D = 220.00 TEST RECORD Start time 12:57 Depth to Drawdown Drawdown CALCULATION: Elapsed time water (Ho) Ratio Shape Factor g See attached sheet mm:ss.0 min m m (H/Ho) Cross Sectional Area A = 2.0E-03 m2 0.5 0.158 Intake Factor F = 13.23 9.5 0.167 0.147 1.00 Basic Time Lag T = 18 mins Taken from graph when H/Ho = 0.37 10.0 0.175 0.146 1.00 0.0125 days 10.5 0.183 0.143 1.02 K= 0.012 m/d 11.0 0.192 0.143 1.02 K= 1.37E-07 m/s 11.5 0.200 0.146 0.97 COMMENTS: 12.0 0.208 0.138 1.01 12.5 0.217 0.144 1.00 13.0 0.225 0.143 0.99 13.5 0.233 0.142 0.98 1.00 14.0 0.242 0.14 0.99 14.5 0.250 0.142 1.00 15.0 0.258 0.143 0.97 15.5 0.267 0.139 1.01 16.0 0.275 0.144 0.98 16.5 0.283 0.14 1.00 17.0 0.292 0.143 1.00 17.5 0.300 0.143 0.99 18.0 0.308 0.142 0.99 0.10 18.5 0.317 0.142 1.00 H/Ho 19.0 0.325 0.143 0.99 19.5 0.333 0.142 0.98 20.0 0.342 0.14 0.98 20.5 0.350 0.14 0.98 21.0 0.358 0.14 1.00 21.5 0.367 0.143 1.00 22.0 0.375 0.143 0.99 0.01 22.5 0.383 0.142 0.98 23.0 0.392 0.14 0.97 0.000 2.000 4.000 6.000 8.000 10.000 12.000 14.000 16.000 18.000 20.000 23.5 0.400 0.139 0.98 Elapsed Time (minutes) 24.0 0.408 0.14 0.98

Printed: 29/05/2012 12:43 BH5 1 rising Data Page 1 Slug Test Analysis Using Hvorslev Shape Factors

VARIABLE HEAD PERMEABILITY TEST Site : Stonepits Benefield Location : East N'hants Depth below top of casing/standpipe to : Project No : Borehole No : BH5 (a) bottom of borehole : m Date :06-Mar-2012 Sheet 1 of 1 (b) bottom of casing : m Ground Level (OD): m Contractor: (c) top of filter material : m Weather : Fine (d) center of piezometer tip : m Type of test : Test 1 - falling head permeability (e) initial ground water level : 7.21 mbd Diameter of casing/standpipe : 0.05 m Height of casing/standpipe above surface : 0.45 m Length of filter: 11.00 m Dia. of filter : 0.05 m Elevation of casing/standpipe above surface : m (OD) Type of piezometer : slotted screen L/D = 220.00 TEST RECORD Start time 12:57 Depth to Drawdown Drawdown CALCULATION: Elapsed time water (Ho) Ratio Shape Factor g See attached sheet Secs min m m (H/Ho) Cross Sectional Area A = 2.0E-03 m2 0.5 0.008 0 Intake Factor F = 13.23 1.0 0.017 0.354 1.00 Basic Time Lag T = 0.095 mins Taken from graph when 1.5 0.025 0.154 0.44 0.0001 days H/Ho = 0.37 2.0 0.033 0.13 0.37 K= 2.250 m/d 2.5 0.042 0.113 0.32 K= 2.60E-05 m/s 3.0 0.050 0.13 0.37 COMMENTS: 3.5 0.058 0.181 0.51 4.0 0.067 0.022 0.06 4.5 0.075 0.137 0.39 5.0 0.083 0.11 0.31 5.5 0.092 0.136 0.38 1.00 6.0 0.100 0.117 0.33 6.5 0.108 0.121 0.34 7.0 0.117 0.116 0.33 7.5 0.125 0.117 0.33 8.0 0.133 0.113 0.32 8.5 0.142 0.112 0.32 9.0 0.150 0.112 0.32 9.5 0.158 0.112 0.32 0.10 10.0 0.167 0.112 0.32 H/Ho 10.5 0.175 0.109 0.31 11.0 0.183 0.108 0.31 11.5 0.192 0.108 0.31 12.0 0.200 0.11 0.31 12.5 0.208 0.116 0.33 13.0 0.217 0.11 0.31 13.5 0.225 0.106 0.30 14.0 0.233 0.106 0.30 0.01 14.5 0.242 0.108 0.31 0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 15.0 0.250 0.108 0.31 Elapsed Time (minutes) 15.5 0.258 0.113 0.32 16.0 0.267 0.106 0.30

Printed: 29/05/2012 12:40 BH5 1 Falling Data Page 1 Slug Test Analysis Using Hvorslev Shape Factors

VARIABLE HEAD PERMEABILITY TEST Site : Stonepits Benefield Location : East N'hants Depth below top of casing/standpipe to : Project No : Borehole No : BH5 (a) bottom of borehole : m Date :06-Mar-2012 Sheet 1 of 1 (b) bottom of casing : m Ground Level (OD): m Contractor: (c) top of filter material : m Weather : Fine (d) center of piezometer tip : m Type of test : Test 1 - falling head permeability (e) initial ground water level : 7.21 mbd Diameter of casing/standpipe : 0.05 m Height of casing/standpipe above surface : 0.45 m Length of filter: 11.00 m Dia. of filter : 0.05 m Elevation of casing/standpipe above surface : m (OD) Type of piezometer : slotted screen L/D = 220.00 TEST RECORD Start time 12:57 Depth to Drawdown Drawdown CALCULATION: Elapsed time water (Ho) Ratio Shape Factor g See attached sheet Secs min m m (H/Ho) Cross Sectional Area A = 2.0E-03 m2 0.5 0.008 0 Intake Factor F = 13.23 1.0 0.017 0.354 1.00 Basic Time Lag T = 0.095 mins Taken from graph when 1.5 0.025 0.154 0.44 0.0001 days H/Ho = 0.37 2.0 0.033 0.13 0.37 K= 2.250 m/d 2.5 0.042 0.113 0.32 K= 2.60E-05 m/s 3.0 0.050 0.13 0.37 COMMENTS: 3.5 0.058 0.181 0.51 4.0 0.067 0.022 0.06 4.5 0.075 0.137 0.39 5.0 0.083 0.11 0.31 5.5 0.092 0.136 0.38 1.00 6.0 0.100 0.117 0.33 6.5 0.108 0.121 0.34 7.0 0.117 0.116 0.33 7.5 0.125 0.117 0.33 8.0 0.133 0.113 0.32 8.5 0.142 0.112 0.32 9.0 0.150 0.112 0.32 9.5 0.158 0.112 0.32 0.10 10.0 0.167 0.112 0.32 H/Ho 10.5 0.175 0.109 0.31 11.0 0.183 0.108 0.31 11.5 0.192 0.108 0.31 12.0 0.200 0.11 0.31 12.5 0.208 0.116 0.33 13.0 0.217 0.11 0.31 13.5 0.225 0.106 0.30 14.0 0.233 0.106 0.30 0.01 14.5 0.242 0.108 0.31 0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 15.0 0.250 0.108 0.31 Elapsed Time (minutes) 15.5 0.258 0.113 0.32 16.0 0.267 0.106 0.30

Printed: 29/05/2012 12:44 BH5 2 Falling Data Page 1 Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

APPENDIX 5

Discharge calculations

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Site: Effective Radius of working phase 100x100m (calculated for rectangular pit after Somerville, 1988) Groundwater Inflow Calculations: Thiem formula 44 or 64 Effective Radius of phase 5 (calculated from funders report ) 3 Where Q = groundwater ingress rate (m /d) k = hydraulic conductivity (m/d) 2 2 h0 = saturated thickness before drawdown (m) Q =k πho [( h−w /)ln r(o / rw )] hs = nominal value for height of seepage face in workings (m) Where r = radius of influence (m)

hw = saturated aquifer thickness after drawdown + hs (m) r = Ch k C = constant = for radial flow 1500-2000 for trenches

rw = radius of working area (m) h = drawdown (m)

r0 = rw + radius of influence (m) k = hydraulic conductivity (m/s)

Assumptions SET VALUES HERE rw = radius of working area (m)

Initial saturated thickness (ho) = 3.7 m Radius of working area (rw) = 44.0 m Drawdown (h) = 3.7 m seepage face (hs) = 0.5 m Seepage face and sat. thickness after dewatering have been given nominal values radius of influence constant = 3000 1500-2000 for trenches, 3000 radial hydraulic conductivity values Min Median Max (m/d) 0.02 1 5 RESULTS - Groundwater Inflow,Q (m/s) 2.31E-07 1.16E-05 5.79E-05 Hydraulic conductivity (m/d)

ho= 3.7 m 0.0 1.0 5.0 Groundwater Inflow,Q 3 3 3 hw = 0.5 m m /d l/s m /d l/s m /d l/s 7.4 0.1 68.2 0.8 197.1 2.3 =' 44.0 m

hs = 0.5 m

radius of influence 5 38 84 m Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

APPENDIX 6

Methodology for impact assessment

May 2012

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

METHODOLOGY FOR IMPACT ASSESSMENT

Potential impacts were assessed with consideration of both the short-term operational and long- term restoration phases. The potential for unplanned incidents, such as spillage of hazardous substances, was also taken into account. The following factors were considered:

ƒ Magnitude of the impact ƒ Spatial extent of the impact ƒ Frequency of the impacts ƒ Timescale over which the impact may occur ƒ Cumulative impacts ƒ Sensitivity of the receiving environment

Mitigation measures and residual impacts have been considered as part of the assessment.

Method of assessment The method of assessment of hydrological and aquatic effects has involved:

ƒ characterisation of the baseline environment ƒ determination of the sensitivity of key catchments and watercourses ƒ evaluation of the significance of predicted effects taking account of the magnitude of effects (before and after mitigation) ƒ evaluation of the sensitivity of the baseline environment affected

A rigorous and consistent approach to the assessment has been adopted using matrices to help classify sensitivity of the resource, and determine the scale and significance of effects.

Baseline sensitivity The characterisation of the baseline water environment has involved the review of extensive data and identification of sensitivities. The characterisation of catchment sensitivities has been guided by the matrix presented in Table A4.1 which lists indicative criteria.

The criteria for sensitivity are based approximately on hierarchy of factors relating to the quality of the aquatic environment. The criteria have been used to guide the analysis of the sensitivity of the baseline hydrological, hydrogeological and water quality environment.

Sensitivity category Sensitivity criteria Adjacent to Application Area Downstream/in catchment High sensitivity SSSI or Aquatic Natura 2000 site Aquatic Natura 2000 site or Wetland watercourse habitat of SSSI immediately downstream/ particular ecological importance adjacent Highly vulnerable groundwater Significant peat deposits on sloping ground Medium sensitivity Wetland watercourse habitat of Aquatic Natura 2000 site or particular ecological importance SSSI further down catchment Moderately vulnerable groundwater Significant peat deposits

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

Sensitivity category Sensitivity criteria Adjacent to Application Area Downstream/in catchment Low sensitivity Low vulnerability groundwater Superficial peat deposits Not sensitive No aquatic habitats or watercourses present No significant groundwater present Table A4.1: Catchment sensitivity classification

Impact prediction and evaluation The prediction and assessment of effects on hydrology, hydrogeology and other aquatic resources has been undertaken using a series of tables to document the various potential impacts from aspects of proposed future mineral extraction. Impacts have been predicted for the proposed future working based upon the guideline criteria for impact magnitudes set out in Table A4.2.

Impact Guideline criteria magnitude High Total loss of, or alteration to, key features of the baseline resource such that post-development characteristics or quality would be fundamentally and irreversibly changed, eg watercourse realignment Medium Total loss of, or alteration to, key features of the baseline resource such that post-development characteristics or quality would be partially changed, eg in- stream permanent bridge works Low Small changes to the baseline resource which are detectable but the underlying characteristics or quality of the baseline situation would be similar to pre- development conditions, eg culverting of very small watercourses Negligible A very slight change from baseline conditions, which is barely distinguishable and approximates to the ‘no change’ situation, eg short-term compaction from plant movements Table A4.2: Impact magnitude

Using these criteria a series of generic impacts have been predicted for the proposed project. Residual effects have also been predicted taking into account site-specific mitigation.

The significance of the predicted effects has been assessed in relation to the sensitivities of the baseline resource. A matrix of significance was developed to provide a consistent framework for evaluation and is presented in Table A4.3. Guideline criteria for the various categories of effect are included in Table A4.4.

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Churchfield Stone Ltd Hydrogeological Assessment: Stonepits Quarry, Benefield VERSION 1.2

Magnitude Sensitivity High Medium Low Negligible High Major Major Moderate Minor Medium Major Moderate Minor Minor Low Moderate Minor Minor None Negligible Minor Minor None None Table A4.3: Significance matrix

Significance Definition Guideline criteria None No detectable change to the No effects on drainage patterns, surface and environment groundwater quality or aquatic habitat Minor A small but detectable change Localised changes in drainage patterns or to the environment groundwater flows, or changes resulting in minor and reversible effects on surface and groundwater quality or aquatic habitats Moderate A larger, but non-fundamental Changes in water quality or quantity affecting change to the environment part of a catchment or groundwaters of moderate vulnerability, or changes resulting in loss of conservation value to aquatic habitats or designated areas Major A fundamental change to the Changes in water quality or quantity affecting environment widespread catchments or groundwater reserves of strategic significance, or changes resulting in substantial loss of conservation value to aquatic habitats and designations Table A4.4: Significance of effects categories

In the above classification, fundamental changes are those which are permanent, detrimental and would result in widespread change to the baseline environment. For the purposes of this assessment, those effects identified as being ‘major’ or ‘moderate’ have been evaluated as ‘significant environmental effects’ and therefore those which may have an adverse effect on the status of waterbodies.

The matrices used to guide the assessment have been applied with flexibility since the evaluation of effects is always subject to particular site-specific characteristics. For this reason, the evaluation of impact significance in particular does not always correlate exactly with the cells in the relevant matrix; where professional judgement and local knowledge may result in a slightly different interpretation of the impact concerned. Cumulative effects have been taken into account through prediction and evaluation of effects at a catchment-wide level.

Impacts to the proposed development at Stonepits Quarry and its environs have been assessed for both the working phases and the restored site. Mitigation measures are discussed in relation to the potential impacts identified. The residual impacts are those which are perceived to exist post-mitigation.

May 2012

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