Level 1 Strategic Flood Risk Assessment Final Report October 2019 www.jbaconsulting.com Newcastle-under-Lyme Borough Council Classification: NULBC UNCLASSIFIED JBA Project Manager Hannah Hogan BA (hons) MA IWA-MCIWEM C.WEM CEnv The Library St Philips Courtyard Church Hill Coleshill Warwickshire B46 3AD Revision History Revision Ref / Date Amendments Issued to Issued 01/02/2019 Draft Report Karl Conyon, Growth & Prosperity Directorate, Stoke-on-Trent City Council 15/04/2019 Second Draft Report Karl Conyon Growth & Prosperity Directorate, Stoke-on-Trent City Council 04/10/2019 Final Report Jemma March, Planning Policy, Newcastle-under-Lyme Borough Council Contract This report describes work commissioned by Karl Conyon on behalf of Newcastle-under-Lyme Borough Council via Faithful & Gould in accordance with the PAGABO professional framework services on the 20th July 2018. Hannah Hogan, Freyja Scarborough and Erin Holroyd of JBA Consulting carried out this work. Prepared by .................................................. Freyja Scarborough BSc MSc Analyst ....................................................................... Erin Holroyd BSc Technical Assistant Reviewed by ................................................. Hannah Hogan MA IWA-MCIWEM C.WEM CENV Chartered Senior Analyst …………….................................................... Hannah Coogan BSc MCIWEM C.WEM Technical Director Purpose This document has been prepared as a Final Report for Newcastle-under-Lyme Borough Council. JBA Consulting accepts no responsibility or liability for any use that is made of this document other than by the Client for the purposes for which it was originally commissioned and prepared. JBA Consulting has no liability regarding the use of this report except to Newcastle-under-Lyme Borough Council. 2018s0964 Newcastle-under-Lyme Strategic Flood Risk Assessment Final report v3.3 2 Acknowledgements We would like to acknowledge the assistance of: Newcastle-under-Lyme Borough Council; Stoke-on-Trent City Council; Staffordshire County Council; Environment Agency; Severn Trent Water; United Utilities; The Canal and Rivers Trust; and, Planners at the neighbouring authorities Copyright © Jeremy Benn Associates Limited 2019. Carbon Footprint JBA is aiming to reduce its per capita carbon emissions. 2018s0964 Newcastle-under-Lyme Strategic Flood Risk Assessment Final report v3.3 3 Executive summary About this report This report provides a comprehensive and robust evidence base on flood risk issues to support the production of the joint Local Plan for Stoke and Newcastle-under-Lyme to 2033. This is a Level 1 Strategic Flood Risk Assessment (SFRA) and it will be used to inform decisions on the location of future development and the preparation of sustainable policies for the long-term management of flood risk. This report covers the Borough of Newcastle-under-Lyme. A separate report covers Stoke-on-Trent City Council. Introduction This Strategic Flood Risk Assessment (SFRA) document replaces the 2008 Level 1 SFRA. The study provides a comprehensive and robust evidence base to support the new Joint Local Plan for Newcastle-Under-Lyme and Stoke-on-Trent. The key objectives are: To understand flood risk from all sources and to investigate and identify the extent and severity of flood risk throughout the borough. This assessment will enable NULBC to apply the Sequential Test in the preparation of the Local Plan, steer development away from those areas where flood risk is considered greatest, ensuring that areas allocated for development can be developed in a safe, cost effective and sustainable manner. To form part of the evidence base and inform the council’s joint Local Plan. To provide guidance for developers and planning officers dealing with applications as well as to enable Staffordshire County Council to fulfil their role as LLFA including advice on the application of SuDS. To provide guidance for developers and planning officers on planning requirements. To ascertain if land will be required for current and future flood management that should be safeguarded as set out in the NPPF. To reflect current national policy documentation including the NPPF and its accompanying Flood Risk and Coastal Change Planning Practice Guidance to enable NULBC to meet its obligations as defined by the NPPF. To supplement current policy guidelines and to provide a straightforward risk-based approach to development management in the area. To make recommendations on the suitability of potential development sites based on flood risk for NULBC's Local Plan. To assess surface water flood risk, using the Environment Agency’s (EA) third generation surface water flood map, the Risk of Flooding from Surface Water map (RoFSW). To develop a report that forms the basis of an informed development management process that also provides guidance on the potential risk of flooding associated with future planning applications and the basis for site-specific Flood Risk Assessments (FRAs) where necessary. To consider a precautionary approach to climate change. To provide a suite of interactive GeoPDF flood risk maps. To assess any strategic flooding issue which may have cross boundary implications and investigate any strategic solutions which can be implemented to reduce the risk To consider and make recommendations to reduce the impact of the cumulative impact of developments. Summary of flood risk Historic flooding records highlight the risk from the Lyme Brook, culverted watercourses and surface water. The areas most affected have been Kidsgrove and Silverdale/ Newcastle. Flooding occurs from a number of different and combined sources and pathways; it can present a range of levels of risk and hazard. Both the causes and consequences of flooding in any given location is very site specific depending on local conditions 2018s0964 Newcastle-under-Lyme Strategic Flood Risk Assessment Final report v3.3 4 such as topography, development or the presence of watercourses. The wide scale scope of this Level 1 investigation, therefore, makes it difficult to emphasise one principal cause of flooding over others at a borough-wide scale. Across the Borough there is flood risk from various sources including fluvial, surface water and sewers. The main risk of fluvial flooding is from the Lyme Brook in Newcastle-under-Lyme, Silverdale and Knutton. There is also a risk of flooding from the River Lea in Madeley and Madeley Heath and smaller tributaries across the Borough. There is a recognised risk of surface water flooding in the borough, particularly in the urbanised areas of Newcastle and Kidsgrove. Incidents were reported in Kidsgrove in 2007, 2009 and 2012. This included flooding due to surface water run-off and excess discharge through drainage systems and culverts. The Local FRM Strategy estimates 632 properties are at risk in the urban area of Newcastle and Silverdale. STW and United Utilities are the water companies responsible for the management of public sewers across different areas of the Borough. The Severn Trent Water Hydraulic Flood Risk Register (HFRR) register has 148 historical reports of sewer flooding in the Newcastle-under-Lyme area. United Utilities have recorded 624 incidents of sewer flooding in the Newcastle- under-Lyme area. The majority of these incidents have been in Kidsgrove, where there are known issues with the capacity of the sewer network. Areas at risk of flooding from groundwater sources are displayed in Appendix A. These maps also display the Detailed River Network showing known ordinary watercourses. There is no record of historic canal overtopping and breach within the study area. There is no risk of flooding in the Borough from large raised reservoirs. Climate change modelling has been undertaken for all the supplied most up to date Environment Agency models. Due to this, the Climate Change outlines are using the most up to date data and in some areas may not be comparable with the broadscale mapped extents used to inform Flood Zone 3a and Flood Zone 2. There are important cross-boundary flood risk impacts to consider in the borough of Newcastle-under-Lyme. Due to catchment topography, a number of watercourses flowing through the borough drain out into other local authorities and feed into other catchments such as the Trent, Severn and Weaver (Figure 9-1). Therefore, any proposed development in the borough must consider cross-boundary impacts from fluvial and surface water flooding. SFRA outputs The following outputs are available: Identification of policy and technical updates. Recommendations of the criteria that should be used to assess future development proposals and the development of a Sequential Test and sequential approach to flood risk. Assessment of the potential increase in flood risk due to climate change. Review of historic flooding incidents. Appraisal of all potential sources of flooding, including Main River, ordinary watercourse, surface water, overland flows - considering both flood routes/paths and storage, sewers, groundwater (including interactions between the aquifers and perched water tables), reservoirs, canals, infrastructure failure and any other significant bodies of water. Mapping showing distribution of flood risk across all flood zones from all sources of flooding including surface water flooding and climate change allowances. Reporting on the standard of protection provided by existing flood risk management infrastructure. Identification of any strategic flooding issues which may have