Preliminary Geoenvironmental Investigation
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Fall 08 Preliminary Geoenvironmental Investigation Land at New Road, Sharow For Carter Jonas LLP Report no: 2103 /1 Date: June 2015 Tel: 01937 545330 • [email protected] • www.lithos.co.uk NEW ROAD, SHAROW SUMMARY OF GEOENVIRONMENTAL ISSUES Job No. 2103 Site area/ha 2.9 hectares (7.1 acres) Client: Carter Jonas LLP NGR: SE 330 718 Site: New Road, Sharow Nearest postcode: HG4 5BS The site is located approximately 1.5km east of Ripon city centre and is currently arable farmland. The site lies within an area known to be at risk of gypsum dissolution related subsidence. Therefore any development across the site must consider the consequences of gypsum related hazards. Lithos were commissioned by Carter Jonas LLP to provide a preliminary geoenvironmental appraisal of the site. It is understood that the site is to be developed with 60 residential dwellings, although a proposed layout has yet to be prepared, and it is strongly recommended that a geophysical survey is completed prior to finalising any scheme. A summary of salient geoenvironmental issues is provided in the table below. Issue Remarks Former uses None of significance. Anticipated Geology The site is likely to be underlain by about 10m of glacial drift, over Sherwood Sandstone bedrock extending to depths of about 25m, over the Roxby Formation, with the Brotherton Formation from about 45m. The shallowest beds of gypsum are likely to lie at depths in excess of 35m. Gypsum Gypsum is present at the base of the Roxby Formation (c. 10m thick at about 35m to 45m bgl), and in the Edlington Formation, up to 35m thick from about 70m bgl. This site lies within Development Control Area C (gypsum present and susceptible to dissolution), and would likely be considered a larger development. Consequently, it must be subject to robust investigation and foundation design. A known gypsum dissolution subsidence feature is located within 100m of the sites boundary. Hazardous gas No special precautions required. Mining & quarrying Beyond CA defined coal fields. No historical quarrying within 250m of site boundary. Flooding & drainage Flood zone 1. Soakaways are unlikely to provide suitable means of surface water disposal. In any case soakaways discouraged in Area C. Anticipated None anticipated. contamination Recommendations for Initially a day’s trial pitting and geophysical survey of site. ground investigation It is likely that Electrical Resistivity Tomography (ERT) will be the most appropriate geophysical technique, but further advice should be sought from a geophysics specialist. If any significant anomalies (potential subsidence features) are identified by the geophysical investigation, it might be necessary to advance rotary cored boreholes, after first considering potential implications for the proposed development. If no significant anomalies are found, boreholes would not be recommended since they can actually have an adverse effect on the hydrogeology - potentially opening up pathways for groundwater movement. This brief summary should not be assumed to represent a complete account of all the potential geoenvironmental issues that may exist at the site. As such it is strongly recommended that the report be read in its entirety. 1 COMMISSION AND BRIEF ............................................................................................. 1 1.1 THE COMMISSION AND BRIEF .......................................................................................................................... 1 1.2 THE PROPOSED DEVELOPMENT ....................................................................................................................... 1 1.3 REPORT FORMAT AND LIMITATIONS.................................................................................................................. 1 2 SITE DESCRIPTION ......................................................................................................... 2 2.1 GENERAL ...................................................................................................................................................... 2 2.2 SITE FEATURES ................................................................................................................................................ 2 3 SITE HISTORY ................................................................................................................. 3 4 ENVIRONMENTAL SETTING ........................................................................................... 4 4.1 GENERAL ...................................................................................................................................................... 4 4.2 GEOLOGY AND HYDROGEOLOGY.................................................................................................................. 5 4.3 PLANNING ADVICE FOR THE RIPON AREA ........................................................................................................ 7 4.4 LAND CONTAMINATION - PART IIA & PLANNING ............................................................................................. 8 5 GROUND INVESTIGATION DESIGN ............................................................................ 10 5.1 ANTICIPATED GROUND CONDITIONS & POTENTIAL ISSUES ............................................................................... 10 5.2 PRELIMINARY CONCEPTUAL SITE MODEL ........................................................................................................ 10 5.3 GROUND INVESTIGATION DESIGN & STRATEGY .............................................................................................. 11 6 CONCLUSIONS & RECOMMENDATIONS ................................................................... 12 6.1 GENERAL .................................................................................................................................................... 12 6.2 GYPSUM DISSOLUTION ................................................................................................................................. 12 6.3 MINING AND QUARRYING ............................................................................................................................ 13 6.4 HAZARDOUS GAS ........................................................................................................................................ 13 6.5 FOUNDATIONS ............................................................................................................................................ 13 6.6 DRAINAGE AND EXTERNAL WORKS ISSUES ...................................................................................................... 13 6.7 CONTAMINATION ........................................................................................................................................ 14 6.8 FURTHER INVESTIGATION ............................................................................................................................... 14 APPENDICES Appendix A – General notes 01 Environmental setting Appendix B – Drawings Drawing Title 2103/1 Site location plan 2103/2 Proposed layout 2103/3 Site features 2103/4 Site photos 2103/5 Preliminary conceptual site model Appendix C - Commission Appendix D – Historical OS plans* Appendix E – Search responses* From Date Content Harrogate Borough Council 11/03/2015 Enquiry response from Building Control Groundsure 10/03/2015 EnviroInsight & GeoInsight reports Appendix F – Ground Stability Declaration Form * Some of this data is not included within the paper copy of this report; most is included in the PDF copy and all is included on the CD FOREWORD (preliminary geoenvironmental investigation report) This report has been prepared for the sole use and reliance of the Client named on page 1 and cannot be relied upon by any other parties without the express written authorisation of Lithos Consulting Limited (Lithos). Any unauthorized third party relies on this report at their own risk and the authors owe them no duty of care. The report presents observations and factual data obtained during our site investigation, and provides an assessment of geoenvironmental issues with respect to information provided by the Client regarding the proposed development. Further advice should be sought from Lithos prior to significant revision of the development proposals. The report should be read in its entirety, including all associated drawings and appendices. Lithos cannot be held responsible for any misinterpretations arising from the use of extracts that are taken out of context. However, it should be noted that in order to keep the number of sheets of paper in the hard copy to a minimum, some information (e.g. full copy of the Landmark/Groundsure Report) is only included within the “electronic”, PDF Report on the accompanying CD. The findings and opinions conveyed in any Desk Study section of the report (including review of any third party reports) are based on information obtained from the sources listed, which Lithos understands are reliable. All reasonable skill, care and diligence has been applied in examining the information obtained. However, Lithos accept no responsibility for inaccuracies in the data supplied or for opinions based on any such inaccurate data. Where the report refers to the potential presence of invasive weeds such as Japanese Knotweed, or the presence of asbestos containing materials, it should be noted that the observations are for information only and should be verified by a suitably qualified expert. Lithos reserve the right to amend their conclusions