Zig Zag Quarry Restoration. Hydrogeological Risk Assessment
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ZIG ZAG QUARRY RESTORATION. HYDROGEOLOGICAL RISK ASSESSMENT. HARLEYFORD AGGREGATES May 2020 UK Company Registration Number: 08610467 +44 (0) 7765 255 197 Registered Office: 23 Westfield Park, Redland, Bristol BS6 6LT www.jhgroundwater.co.uk Zig Zag Quarry HRA Harleyford Aggregates REVISION Record Revision 0 Revision 1 Revision 2 Revision 3 Project Number 1164 1164 File reference 1164/001_r1_Rev0 1164/001_r1_Rev1 Description of Working Draft Final Revision Prepared by Julian Hatherall Julian Hatherall Revision date 16/10/19 28/05/20 Copyright. All copyright in this document is reserved. Disclaimer. This report has been prepared by JH Groundwater Ltd in a manner consistent with the level of care and skill ordinarily exercised by members of the geological and engineering professions practising at this time, within the agreed scope and terms of contract, and taking account of the manpower and resources devoted to it by agreement with its client. This document contains data, information and may contain conclusions and recommendations. The conditions described in this report are based on data available at the time, however, environmental and other conditions, including regulatory requirements may change with time and as other data and/or information becomes available. Data is limited in a number of cases and all potential constraints and liabilities associated with the site may not necessarily have been revealed. Potential exists for variations in soil and groundwater conditions between and beyond specific locations discussed in the report. The risk of undiscovered environmental impairment of the property cannot be ruled out. JH Groundwater Ltd cannot therefore warrant the actual conditions at the site and advice given is limited to those conditions for which information is held by JH Groundwater Ltd at the time. The findings and opinions presented in the report are based on information from a variety of sources and reasonable effort has been made to ensure that the information is accurate, that the opinions expressed are sound and the conclusions are based on appropriate implementation of the proposals. However, JH Groundwater Ltd cannot be made liable for any errors or omissions or for any losses or consequential losses resulting from decisions based on the information. The advice and opinions in this report should be read and relied on only in the context of the report as a whole along with any accompanying covering letter, e-mail or note. This report is provided only to the client with whom a contract has been agreed. Should the client wish to release this report to any other third party for that party’s reliance, JH Groundwater Ltd accepts no responsibility to any third party to whom this report or any part thereof is made known. JH Groundwater Ltd accepts no responsibility for any loss or damage incurred as a result, and the third party does not acquire any rights whatsoever, contractual or otherwise, against JH Groundwater Ltd except as expressly agreed with JH Groundwater Ltd in writing. Zig Zag Quarry HRA Harleyford Aggregates Contents 1 Introduction 1 1.1 Background ................................................................................................................................................. 1 1.2 Objectives and Scope of Works .................................................................................................................. 1 1.3 About the Author ........................................................................................................................................ 2 2 Site Characterisation 3 2.1 Development Summary .............................................................................................................................. 3 2.2 Geology ....................................................................................................................................................... 4 2.3 Hydrology .................................................................................................................................................... 6 2.4 Surface Water ............................................................................................................................................. 7 2.5 Hydrogeology .............................................................................................................................................. 7 2.6 Water Resources, Licensed Abstractions and Private Water Supplies ..................................................... 11 2.7 Conservation Interests .............................................................................................................................. 12 2.8 Water Quality ........................................................................................................................................... 13 3 Geological and Hydrogeological Conceptual Model 14 4 Hydrogeological Risk Assessment 16 4.1 Introduction .............................................................................................................................................. 16 4.2 Overview of Proposals .............................................................................................................................. 16 4.3 Source, Pathway, Receptor ....................................................................................................................... 17 4.4 Risk Assessment ........................................................................................................................................ 18 4.5 Review of Technical Precautions .............................................................................................................. 19 5 Requisite Surveillance 20 5.1 Risk Based Monitoring Scheme ................................................................................................................ 20 5.2 Contingency Action Plan ........................................................................................................................... 21 6 Conclusions 22 Zig Zag Quarry HRA Harleyford Aggregates FIGURES APPENDICES Appendix 1 Waste Recovery Plan including the Restoration Plans Appendix 2 Envirocheck Report Appendix 3 Envirocheck Geological Mapping Zig Zag Quarry HRA Harleyford Aggregates 1 Introduction JH Groundwater Limited (JHG) were commissioned by Aardvark EM (AEM) to undertake a Hydrogeological Risk Assessment (HRA) for quarry restoration using indigenous waste mineral and imported inert waste materials at Zig Zag Quarry. These are currently operated by Harleyford Aggregates Ltd (Harleyford). This report describes the hydrogeological risk assessment carried out by JHG to assess if the proposals are likely to adversely impact controlled waters in the locality, and to support the environmental permit application for the restoration. Please note that whilst the assessment refers to restoration of the quarry, this includes both the quarry void and the silt ponds located to the north. The purpose of this document is to assess the proposals and whether there are any significant risks, from a controlled waters perspective, in this location. It is understood that additional risk assessment work may be requested at a later stage but that the assessment outlined here would be reviewed by the EA as a statutory consultee at pre-application stage to identify specific issues of concern and define the scope of risk assessment required. 1.1 Background Details of the planned restoration are provided in Appendix 1. However, to summarise, planning approval for the extension of the quarry and phased restoration was granted by Devon Council in October 2016. Specifically: x Harleyford plan to extract 500,000 tonnes of sand and gravel over a 10-year period. x The approved planning application states that the restoration will include the importation of 285,00 tonnes of inert waste over a five-year period and this will be undertaken in a phased approach as shown in Appendix 1. 1.2 Objectives and Scope of Works To identify potential risks to controlled waters resulting from the development proposals the following assessment has been completed: x Undertake a data review to establish the hydrogeological Conceptual Site Model (CSM) and complete a qualitative hydrogeological impact assessment. This includes: 1164_AEM_Zigzaq_Qualhra_Rev1.Docx Page 1 Zig Zag Quarry HRA Harleyford Aggregates o Definition of the local geological and hydrogeological conditions; o Definition of the development environmental setting; o An outline of engineering proposals; o Qualification of risks to identified receptors through completion of a proportional Hydrogeological Risk Assessment (HRA) to assess potential positive or adverse impacts on controlled waters that may arise from proposed development. x A site visit to review the environmental setting; and x Reporting in a succinct manner setting out the assessment, conclusions, recommendations and a discussion of likely risks and limitations. 1.3 About the Author This assessment has been completed by Julian Hatherall. Julian is a Chartered Geologist with over 22 years’ experience providing advice on groundwater and hydrogeological issues and has significant knowledge of the assessment and management of groundwater and water resources. His experience encompasses both contaminant and water resource hydrogeology and includes baseline groundwater studies, groundwater risk assessment, groundwater advice in relation to the development of infrastructure and buildings including drainage, groundwater in the