River Hull Advisory Board River Hull Integrated Catchment Strategy May 2016 Strategy Document Final report "Providing long term sustainable management of flood risk" This document was issued and approved as follows: Version Control Version Originator Checked Date Comment 1 BK AM 10/07/2015 2 CB AM 30/03/2016 3 BK AM 31/05/2016 Partner Approvals Record Organisation Approver Date of Approval East Riding of Yorkshire Council Cabinet 7 July 2015 Hull City Council Cabinet 22 June 2015 Area Flood and Coastal Environment Agency 3 July 2015 Risk Manager Beverley & North Holderness Board 8 July 2015 Internal Drainage Board Yorkshire Water Flood Risk Manager 9 July 2015 River Hull Advisory Board Board 10 July 2015 Through the above approval the partners are recognising the work that has been carried out to produce the River Hull Integrated Catchment Strategy which sets out a holistic and strategic approach to managing the flood risk for the River Hull catchment. The partners have agreed to have regard to this Strategy in formulating their future proposals for managing flood risk within the catchment. The progression of individual projects or interventions identified within this Strategy will be subject to the normal assurance and approval processes of the individual body concerned and those of any relevant funding body. i RIVER HULL ADVISORY BOARD RIVER HULL INTEGRATED CATCHMENT STRATEGY MAY 2016 ©2016. East Riding of Yorkshire Council. All rights reserved. No part of this publication may be reproduced in any form or by any means without the prior permission of East Riding of Yorkshire Council ii Contact information For further information about this Strategy, please contact us using the details below. Email: [email protected] Web: www.eastriding.gov.uk/flooding Post: Flood Risk Strategy, County Hall, Cross Street, Beverley, HU17 9BA iii THIS DOCUMENT It is important for the reader to fully understand that this document is produced for consideration by the approval bodies of multiple organisations with differing constitutional and accountability arrangements, these are: • The Cabinet of Elected Members: East Riding and Kingston upon Hull City Councils • EA (Delegated to Area Flood and Coastal Risk Manager) • The Beverley and North Holderness Internal Drainage Board • Board of Directors: Yorkshire Water (Delegated to Senior Officer) ; and in respect of environmental assessments: • Natural England: (Delegated to Senior Officer, NE York) All 5 flood risk management authorities and the Local Enterprise Partnership (LEP) are funding authorities. Capital funding for this project will be directed in the following ways: • Humber LEP: Multiple sources of funding through a local assurance system and commitments in the Humber growth Deal • Yorkshire Water: Regulated funding within parameters agreed by Ofwat (the Water Services Regulation Authority) • EA: Flood Defence Grant-in Aid only within a national assurance framework on behalf of Defra. Detailed information about governance arrangements for capital funding can be found at 12.4. Whilst an exhaustive effort has been made to address the requirements of all the approving bodies, should clarification or further supplementary information be required the reader should contact a member of the RHICS project team in advance of approval deadlines. iv CONTENTS This Document ...................................................................................................................................................... 4 Contents .................................................................................................................................................................. 5 Figures ...................................................................................................................................................................... 8 Section 1: Executive Summary ........................................................................................................................... 1 1.1 Background ........................................................................................................................................... 1 1.2 Project innovation ............................................................................................................................... 1 1.3 Modelling and economics .................................................................................................................. 2 1.4 Option development .......................................................................................................................... 2 1.5 Other flood risk management actions ........................................................................................... 4 1.6 Environmental assessment ................................................................................................................ 7 1.7 Consultation ......................................................................................................................................... 7 1.8 Implementation .................................................................................................................................... 7 1.9 Further actions .................................................................................................................................... 7 Section 2: Introduction and Background to the Strategy ............................................................................ 9 2.1 Introduction ......................................................................................................................................... 9 2.2 Strategy vision ...................................................................................................................................... 9 2.3 Background ......................................................................................................................................... 11 2.4 Aims and objectives .......................................................................................................................... 15 2.5 Governance ........................................................................................................................................ 19 2.6 The study rationale ........................................................................................................................... 21 2.7 Strategy development approach .................................................................................................... 22 2.8 Study plan and strategy development .......................................................................................... 25 Section 3: Catchment Overview ..................................................................................................................... 31 3.1 River Hull catchment and study area ........................................................................................... 31 3.2 Environmental context .................................................................................................................... 37 3.3 Other relevant plans and strategies ............................................................................................. 42 Section 4: Flood Risk .......................................................................................................................................... 51 4.1 Definitions........................................................................................................................................... 51 4.2 Causes of flooding ............................................................................................................................ 51 4.3 Flood management in the catchment ........................................................................................... 54 4.4 Assessment of current flood risk .................................................................................................. 57 4.5 Flood risk in the future .................................................................................................................... 58 Section 5: Hydraulic Modelling ......................................................................................................................... 63 5.1 Introduction ....................................................................................................................................... 63 v 5.2 Model construction .......................................................................................................................... 64 5.3 Design event and modelling of existing condition..................................................................... 70 Section 6: Economic Appraisal ......................................................................................................................... 77 6.1 Introduction ....................................................................................................................................... 77 6.2 Residential damages .......................................................................................................................... 77 6.3 Non-residential damages ................................................................................................................. 78 6.4 Agricultural damages ........................................................................................................................ 80 6.5 Other damages .................................................................................................................................