DAB Geotechnics MICK GEORGE LTD. PROPOSED RINGSTEAD GRANGE QUARRY HYDROLOGICAL AND HYDROGEOLOGICAL ASSESSMENT DAB Geotechnics Proposed Ringstead Grange Quarry - Hydrological and Hydrogeological Assessment PROPOSED RINGSTEAD GRANGE QUARRY HYDROLOGICAL AND HYDROGEOLOGICAL ASSESSMENT April 2012 Name Signature Date Prepared by D. A. Blythe 30th April 2012 Issue Status Final Purpose For Client’s information Prepared by DAB Geotechnics 3, Tweed Avenue, Ellington, MORPETH, Northumberland, NE61 5ES Tel. No. 07711 168524 E-mail [email protected] DABGeot/11093/Final Proposed Ringstead Grange Quarry - Hydrological and Hydrogeological Assessment PROPOSED RINGSTEAD GRANGE QUARRY HYDROLOGICAL AND HYDROGEOLOGICAL ASSESSMENT Table of Contents Page 1. INTRODUCTION 1 1.1 General 1 1.2 Location 2 1.3 Topography 2 1.4 Development Proposal 2 2. GEOLOGY 3 2.1 Published Information 3 2.2 Exploratory Drilling 3 2.3 General Succession 3 2.3.1 Superficial Deposits 3 2.3.2 Bedrock Strata 5 2.4 Geological Structure 8 2.5 Mining and Ground Stability 8 2.5.1 General 8 2.5.2 Mining Stability 8 2.5.3 Ground Stability 8 3. HYDROLOGY 9 3.1 Rainfall 9 3.2 Catchment and Principal Drainage Paths 9 3.3 Site Specific Drainage Details 10 3.4 Flood Risk 10 3.5 Greenfield Runoff Rate 10 3.6 Licensed and Unlicensed Surface Water Abstractions 11 3.7 Surface Water Discharges 12 3.8 Surface Water Quality 12 4. HYDROGEOLOGY 14 4.1 Environment Agency Classification 14 4.2 Hydraulic Properties of the Strata 14 4.2.1 Superficial Deposits 14 4.2.2 Bedrock Strata 14 i DABGeot/11093/Final Proposed Ringstead Grange Quarry - Hydrological and Hydrogeological Assessment Page 4.3 Exploratory Borehole Information and Groundwater Monitoring Stations 15 4.4 Groundwater Quality 17 4.5 Licensed and Unlicensed Groundwater Abstractions 17 4.6 Waste Handling, Disposal and Treatment Sites and Waste Transfer Stations 18 5. PREDICTED EFFECTS OF PROPOSED QUARRY DEVELOPMENT AND 19 MITIGATION MEASURES 5.1 Management of Water on the Proposed Quarry Site 19 5.2 Groundwater Resources 19 5.2.1 Estimated Groundwater Inflow Rates 19 5.2.2 Effect of Drawdown 21 5.2.3 Swelling and Shrinkage of Bedrock Strata 22 5.2.4 Settlement of Backfill 22 5.2.5 Groundwater Quality 23 5.3 Surface Water Resources 23 5.3.1 Flood Risk 23 5.3.2 Attenuation Storage Volumes 24 5.3.3 Flooding of Station Road 26 5.3.4 Surface water Abstractions 26 5.3.5 Surface Water Quality 26 6. SUMMARY 27 7. REFERENCES 28 FIGURES PHOTOGRAPHS APPENDIX A LANDMARK ENVIROCHECK REPORT ABBENDIX B CORRESPONDENCE WITH EAST NORTHAMPTONSHIRE COUNCIL APPENDIX C SCOPING OPINION FROM THE ENVIRONMENT AGENCY APPENDIX D 1/10,000 SCALE GEOLOGICAL MAPS APPENDIX E BGS ARCHIVE BOREHOLE RECORDS APPENDIX F MINING AND GROUND STABILITY REPORT APPENDIX G FLOOD RISK ASSESSMENT APPENDIX H ATTENUATION STORAGE CALCULATIONS ii DABGeot/11093/Final Proposed Ringstead Grange Quarry - Hydrological and Hydrogeological Assessment 1. INTRODUCTION 1.1 General Mick George Ltd. (Mick George) proposes to extract limestone at its Ringstead Grange site and restore the exhausted workings using imported inert fill materials. DAB Geotechnics was appointed by Mick George to undertake a hydrological and hydrogeological assessment of the proposed quarry. The study has entailed: (i) the provision of a Landmark, ‘Envirocheck’, report to determine the location of all licensed surface and groundwater abstractions, discharge consents, landfill sites and pollution incidents at distances of up to 2km from the centre of the site (Appendix A); (ii) liaison with East Northamptonshire Council with regard to the location of any unlicensed (private) water supplies within at least 1km of the site (Appendix B); (iii) reference to the scoping opinion provided by the Environment Agency in its letter to Northamptonshire County Council dated 8th November 2011 (ref. no. AN/2011/113241/01-L02), a copy of which is presented in Appendix C. (iv) an examination of the geological maps and reports published by the British Geological Survey (BGS) and the provision of an Envirocheck report based on 1/10,000 scale digital information (Appendix D); (v) reference to a number of relevant borehole logs held on the BGS GeoRecords archive (Appendix E); (vi) the acquisition of an Envirocheck mining and ground stability report (Appendix F); (vii) an examination of the most recent aerial photographs; (viii) the compilation of a flood risk assessment in accordance with the National Planning Policy Framework (Department for Communities and Local Government, 2012a) (Appendix G); and (ix) an assessment of the possible effects on surface and groundwater resources and the mitigation measures that will be undertaken. 1.2 Location The proposed development is located about 1.5km south-west of Ringstead and 2km north-west of Raunds in an area administered by East Northamptonshire and Northamptonshire County Councils (Figure 1). The site comprises arable agricultural land and is bounded along its south- eastern margin by a wooded valley that lies adjacent to the A45 public road. Access to the quarry will be gained from the B663 (Raunds or London Road) located to the north-east. The Grid Reference for the centre of the site has been taken as 498050 273900 (1/50,000 scale Ordnance Survey Map Sheet 141 Kettering, Corby & Surrounding Area). An aerial photograph is presented as Figure 2. 1 DABGeot/11093/Final Proposed Ringstead Grange Quarry - Hydrological and Hydrogeological Assessment 1.3 Topography The site occupies an area of 64.3 hectares and is located in an area of gently undulating land. Surface elevations range from about 66m above Ordnance Datum (AOD) in the east to 53m AOD in the west and fall towards the north-west, west and south-west. 1.4 Development Proposal Details of the proposed working scheme for the quarry are contained within the Environmental Statement and are shown on the Working Scheme Plan (Dwg. No. R15/03) and the Indicative Phasing Plans (Dwg. Nos. R15/05). The quarry excavations will cover an area of about 52 hectares and will be worked in a south-westerly and then north-easterly direction along a succession of NW-SE aligned cuts or development phases. The quarry excavations will reach a maximum of about 12m below ground level. The soils will be stripped in a progressive fashion. The initial volumes will be temporarily stored, but the remainder will be placed directly to bed as the exhausted workings are backfilled to restoration level using overburden, quarry discard and imported inert materials. The existing topography and landform will be largely replicated. The development has been designed to minimize the area of disturbance at each stage of the development with land either remaining in agricultural production or restored for that use. Surface runoff will be further attenuated by creating a number of wetland areas of ecological interest (Conceptual Restoration Plan, Dwg. No. R15/14). Surface runoff from the working areas and any groundwater abstracted from the excavations will be pumped and drained to settlement lagoons. The treated water will be discharged into an unnamed tributary of Hog Dyke, subject to the consent of the Environment Agency. Surface runoff from the restored areas that will be created in the northern part of the site will be drained to newly created wetland areas and to the existing agricultural drainage system. Measures will be taken to alleviate a problem of minor flooding of Station Road adjacent to the cemetery. 2 DABGeot/11093/Final Proposed Ringstead Grange Quarry - Hydrological and Hydrogeological Assessment 2. GEOLOGY 2.1 Published Information The geology of the quarry area has been determined by reference to the following maps and reports that have been published by the British Geological Survey (BGS): 1/50,000 scale Geological Map, Sheet 186 Bedrock and Superficial Deposits Edition (2006); ‘Geology of the Wellingborough District’ (Barron et al., 2006); and 1/10,000 scale digital maps presented in Appendix D. 2.2 Exploratory Drilling Details of 10 exploratory boreholes, some of which provide details of the groundwater conditions, have been obtained from the BGS GeoRecords website. Copies of the borehole logs are provided in Appendix E and their locations are shown on Figure 3. A total of 20 boreholes (nos. 1-20) were first drilled on the site by the landowner, Foster Farms Ltd. in October 1988. These were extended to a maximum depth of 8.2m using a tractor mounted rotary blasthole rig. Eight rotary cored and flight augered boreholes were then drilled on the site by Amey Roadstone Corporation in December 1988 and January 1989 (nos. ARC1-8). A reconnaissance borehole investigation was carried out by Steetley Quarry Products Ltd. in May 1989, when 2 cored boreholes (nos. RC89/1-2) and 11 openholes (nos. RO89/3-13) were drilled. A more detailed drilling programme comprising 3 cored boreholes and 23 openholes was undertaken in January 1990 (nos. RG90/1-3 & R90/1-23 respectively). Finally, a site investigation comprising nine boreholes (nos. MG1-9) was completed by Mick George in 2011. Four of these boreholes have been instrumented to allow groundwater monitoring. The borehole locations are shown in Figure 4. The exploratory boreholes show that the lateral extent of some of the bedrock strata differs from that shown on the BGS maps. 2.3 General Succession 2.3.1 Superficial Deposits 2.3.1.1 Recent (Flandrian) Alluvium Recent deposits of alluvium are present along the course of the River Nene, Hog Dyke and their tributaries (1/10,000 scale Superficial Geology map, Appendix D). These generally comprise sand, silt and clay and reach up to 4m in thickness. 2.3.1.2 River Terrace Deposits Deposits of sand and gravel along the valley of the River Nene are regarded as river terrace deposits.