Strategy Approval Report Authority strategy KY09 reference Defra/WAG LDW 1559 number Promoting Portsmouth City Council authority Strategy name Portsea Island Coastal Strategy Study Typical wave overtopping along Clarence Esplanade (Flood Cell 1b) - photo courtesy of The News Date April 2010 Version 2 StAR for Portsea Island Coastal Strategy Study Version Status Signed off by Date signed Date issued 1 First Submission to NRG 2 Updated Submission to NRG April 2010 ii Portsmouth City Council Portsea Island Coastal Strategy Study Contents Approval history sheet - v Scheme of Delegation cover sheet - vii 1. Executive summary and Directors briefing paper ........................................................... 1 1.1 Introduction and background 1 1.2 Problem 1 1.3 Options 2 1.4 Recommended strategy 2 1.5 Economic case and priority Score 3 1.6 Environmental and social considerations 4 1.7 Risks 4 1.8 Implementation 4 1.9 Contributions and funding 6 1.10 Status 6 1.11 Recommendations 6 1.12 Director’s Briefing Paper 7 2 Business Case ............................................................................................................ 19 2.1 Introduction and background 19 2.2 Problem 21 2.3 Options Considered 26 2.4 Costs of options 30 2.5 Benefits of Options 34 2.6 Environmental and social issues 35 2.7 Choice of Preferred Option 38 2.8 Other Considerations 46 3 Strategy Plan............................................................................................................... 48 List of Tables Table 1- Benefit-cost ratios and priority scores Table 2 - Risks and mitigation Table 3 - Strategy costs Table 4 - Summary of flood risk in each flood cell Table 5 - Options Considered for Each Flood Cell Table 6 – Whole life Cash and Present Value Costs for Options Assessed Table 7 - Strategy expenditure profile (£k) Table 8 – Summary of PV Benefit by Flood Cell Table 9 - Summary of Visual Impacts in Year 0, Year 50 and Year 100 Table 10 – Summary of Assessment of Preferred Option Table 11 - Benefit Cost Summary Table for Flood Cell 1 Table 12 - Benefit Cost Summary Table for Flood Cell 2 Table 13 - Benefit Cost Summary Table for Flood Cell 3 Table 14 - Benefit Cost Summary Table for Flood Cell 4 Table 15 - Benefit Cost Summary Table for Flood Cell 5 Table 16 - Benefit Cost Summary Table for Flood Cell 6 Table 17 - Benefit Cost Summary Table for Flood Cell 7 Table 18 – Summary of Outcome Measure scores Table 19 – Implementation programme Table 20 - Spend Profile Summary Table 21 – Risks and Mitigation April 2010 iii Portsmouth City Council Portsea Island Coastal Strategy Study Supporting Documents (as shown below available on request) - Relationship between supporting documents and the StAR is explained in the flow chart below StAR Strategy Appraisal Report Overarching Document Appropriate SEA Coastal Processes Assessment Economics Report Appraisal Process Contamination Risk Report Coastal Defences Assessment of likely Methodology Existing Environment Existing Situation Geomorphology Report Significant effect Damages Environmental Site Investigation Coastal Conditions Existing Defences Appropriate Costs Assessment Risk Assessment Sediment Processes Intervention Options Assessment Results of Options Conclusions In Combination Conclusions Conclusions Numerical Modelling Report Wave Modelling Coastal Change Post Adoption Addendum 2010 Addendum 2010 Joint Probability Data Statement Statement of Case Response to NRG Response to NRG Hydrodynamic Beach Plan Shape Consultation Justification of ROPI Issues Sep 09 Issues Sep 09 Modelling Modelling Summary Flood Propagation Modelling Addendum 2010 Response to NRG Issues Sep 09 April 2010 iv Portsmouth City Council Portsea Island Coastal Strategy Study APPROVAL HISTORY SHEET Strategy Title: Portsea Island Coastal Strategy Study CPA Project Code: KY09 CPA Project Manager: Bret Davies (H&PCP) Date of StAR: July 2009 Consultant Project Manager: Ian Taylor Consultant: Halcrow CPA& EA STAFF INVOLVEMENT Position Name Signature Date “I have reviewed this document and confirm the project meets EA and Defra/WAG criteria and recommend approval in the indicative whole life cost of £372,000,000” Originator (PM) Bret Davies (H&PCP) Reviewer (Project Lyall Cairns (H&PCP) Executive) “I confirm I am content for the starategy as described in this document to proceed for approval and that strategic level risks have been identified” Client Representative Simon Moon (PCC) NEAS Unit Manager “I have reviewed this document and confirm that it complies with the current StAR guidelines” StAR Reviewer (UQM) Allisdair Pitcher “I confirm I am content that the strategy as described in this document contributes to the delivery of our FRM Policy objectives as defined in the relevant CFMPs/SMPs, and that the strategy can proceed for approval” Regional FRM Strategic and Development Gary Lane Planning Team Leader “I confirm the project is ready for submission to PAB/NRG” Operations Manager Paul Sedgwick PAB – Project Assessment Board NRG – National Review Group (Strategies less than £2 million) (Strategies greater than £2 million) (Delete as appropriate) Date of Meeting: Chairman: StAR Amendment No: Presenter(s): Detailed record of any comments/actions required/additional information provided, to be appended to the StAR for onward transmission Recommended for approval: Date: In the sum of £: STRATEGY APPROVAL Head of NCPMS and officers in accordance with the Environment Agency’s SoD: Specified Officer; Regional Director; Director of Environment Agency Operations; Chief Executive or Director of Finance: Environment Agency Board StAR Submitted Date: By: Strategy Approval Date: In the sum of: £ Defra or WAG APPROVAL (Delete as appropriate) April 2010 v Portsmouth City Council Portsea Island Coastal Strategy Study Submitted to Defra / WAG or Not Date: Applicable (as appropriate) StAR Amendment No. (if different): Defra/ WAG Approval: or Not applicable Date: (as appropriate) April 2010 vi Portsmouth City Council Portsea Island Coastal Strategy Study FINANCIAL SCHEME OF DELEGATION (FSoD) COVERSHEET 1. Project Start date September 2001 Portsea Island Coastal Strategy Study name End date July 2009 Business Portsmouth City Council (M032) Programme FDGIA (Capital) unit [EA - Southern Region] Regional Head Office Project ref. KY09 FSoD ref. FSoD ref. 2. Role Name Post Title Project Sponsor Kathy Wadsworth PCC Head of Environment and Transport Project Executive Lyall Cairns H&PCP Team Leader Project Manager Bret Davies H&PCP Coastal Engineer 3. Outline Risk Assessment (ORA) Category Low Medium High 4. Delegation FSoD schedule Description Regional – up to Environment Agency – up to A1 Non FRM project £5m £5m A2 FRM project within approved strategy £5m capital £50m WLC Defra/£5m capital NAW A3 FRM project outside of approved strategy £5m capital £50m WLC Defra/£5m capital NAW A5 Consultancy project £300k £500k A9 FRM Strategy £500k £50m WLC Defra/£5m capital NAW O1 IS/IT project -- £5m T2 Purchase or lease of land and buildings £40k purchase/£10k pa lease £5m 5. FSoD value £k Preparation costs for Form A/Business Case/PAR/FRM Strategy - Project costs - Whole Life Costs (WLC) of FRM Project or Strategy 372,000 6. N/A Low Medium High Required level of Environmental Impact Assessment (EIA) SEA 7. FSoD approver name Post title Signature Date Paul Leinster Chief Executive Chris Smith Environment Agency Board FSoD consultee name Post title Signature Date RED AMBER GREEN Ken Allison PAB/NRG Chair Miles Jordan National Capital Harvey Bradshaw Regional Director Nigel Reader Director of Finance David Jordon Director of Operations 8. Regional Head Office Latest FSoD authorised Form G Form G value (£k) FSoD ref. FSoD ref. cost (£k) 1 April 2010 vii Portsmouth City Council Portsea Island Coastal Strategy Study 2 3 April 2010 viii 1 EXECUTIVE SUMMARY Submission to obtain strategy approval Southern Region: Portsea Island Coastal Strategy Study £372 million Sponsoring Director: Harvey Bradshaw – Environment Agency Regional Director (Southern) Approval route Section A9 of the Financial Scheme of Delegation states that, for whole life costs in a Flood Risk Management Strategy, Environment Agency Board approval is required in excess of £100,000,000 Route: Portsmouth City Council: Full Council Approved, July 2009 Regional Flood Defence Committee: Approved, 2009 Environment Agency: National Capital Programme Manager Miles Jordan National Review Group Ken Allison Regional Director Harvey Bradshaw Director of Operations David Jordan Director of Finance Nigel Reader Chief Executive Paul Leinster 1.1 Introduction and background 1.1.1 This report describes the proposals for a 100 year flood and coastal erosion risk management strategy for Portsea Island, Portsmouth, Hampshire. The strategy has been led by Portsmouth City Council (PCC) and developed in partnership with the Environment Agency. This strategy, in combination with the Portchester Castle to Emsworth coastal flood and erosion risk management study (2009), completes the long-term strategic approach to Portsmouth’s entire coastline. 1.1.2 The study area is a low-lying island and is home to the City of Portsmouth, the UK’s only island city. The City is at significant risk of flooding with 4,211 residential, 364 commercial and 48 Ministry of Defence (MoD) properties currently at risk from a 0.5% annual exceedence probability of flooding (AEP) due to breaching of the existing coastal defences. 1.1.3 Due to climate change the number of properties at risk in 2109 for a 0.5% AEP event would increase