Report to The:- Cabinet
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Report to the:- Wards All Cabinet – 25 July 2011 Hull City Council Aqua Greens Progress Report Report of the City Planning Manager on behalf of the Corporate Director for Regeneration 1. Purpose of the Report and Summary 1.1 The purpose of this report is to brief members on the Aqua Greens project progress. The project has reached the end of the feasibility stage and a review of the document prepared by the Councils Flood Risk Planning Manager is presented below, it can be used alone or as a guide when viewing the document. Future funding options have been explored and recommended next steps are given. 1.2 The council developed a Surface Water Management Plan which was completed in December 2009, the plan recommended surface water storage options as Aqua Greens – dual purpose flood storage and amenity green spaces – at Orchard Park and Derringham. The council retained Halcrow Group Limited to deliver the feasibility study for these two locations. Funding is via DEFRA surface water management grant and Yorkshire Flood Defence Committee Local Levy. 1.3 The study has investigated the options to develop a business case to fund technically, environmentally and financially beneficial schemes at both sites through hydraulic modelling, survey and investigations. 1.4 Aqua Greens have been shown as feasible at both sites with flood storage options at Springhead Park Golf Course in Derringham and diversions of Creyke and Wanlass Beck north of Cottingham and an Aqua Green storage site protecting Orchard Park. Both schemes present some wider benefits to Willerby and Cottingham respectively. 1.5 Additional schemes are being promoted by East Riding of Yorkshire Council, these schemes look to address the origins of flood flows nearer their source to the west of the city. Funding organisations recognise that there are benefits to the city in these additional schemes and have recommended that they receive joint bids for funding where ERYC and HCC schemes are hydraulically dependant upon each other. 1.6 All appraisal information is being shared and joint funding bids are currently being prepared for DEFRA grant in aid and European Regional Development Fund financial support, these would be match funders delivering 100% of scheme costs. This will give the maximum benefits to all residents and businesses across the whole catchment and will show close partnership working between two Lead Local Flood Authorities. 2. Recommendations It is recommended that Cabinet: 2.1 Note the findings of the Aqua Greens Feasibility document: • Aqua Greens flood storage solutions are economically and technically feasible at Derringham and Orchard Park • A viable business case has been made to attract external funding to develop the detailed design and construction of the schemes 2.2 Approve the progression of the Aqua Greens options in combination with ERYC schemes: • A combined Willerby and Derringham scheme and a combined Cottingham and Orchard Park scheme • Joint funding submissions to DEFRA and the ERDF would be more successful than a bid by HCC alone • Schemes to be progressed as detailed in the Options section • This approach delivers the recommendations made in sections 8.1 and 8.2 of the Independent Review Board investigations of the 2007 floods in Hull 3. Options and Risk Assessment 3.1 Joint DEFRA GiA and ERDF bids are being completed by ERYC and HCC to ensure funding deadlines are met. All ongoing modelling and studies are being developed in a manner to allow joint schemes to be progressed. 3.2 The Derringham Aqua Green option could work as an additional storage site to the Great Gutter Valley scheme, the feasibility works for this joint scheme will begin in the 2011 / 2012 financial year, the outputs of the Derringham Aqua Greens feasibility will contribute to this. Both options working together would provide upstream storage above Willerby and storage further down the catchment around Derringham, this would present a catchment wide solution which would reduce flood risks to the maximum amount of people across the two administrative boundaries. 3.3 The Orchard Park Aqua Green proposed option allows both authorities schemes to be combined, the ERYC scheme is considering conveying flows away from the north of Cottingham and the original Aqua Green options at this location looked at storing flows before they reach Orchard Park. This has allowed both schemes to be combined, the Aqua Green feasibility works have considered this and the resultant investigations will feed directly into the ERYC Northmoor feasibility works in 2011 / 2012. A conveyance / storage option gives the maximum benefit to Cottingham and Orchard Park and when combined with the ERYC Raywell Valley scheme (currently under construction) they will vastly reduce the chances of a significant flood event affecting this area. 3.4 The project partners are working to the below timescales, these are still being confirmed at this early stage, the Flood Risk Planning Manager will update committee following the submission to the EA Project Assessment Board (PAB) early in 2012. ERDF / Yorkshire Forward Outline Business Plan submission – June 2011 EA PAB joint scheme feasibility submission – Jan 2012 EA PAB joint scheme detailed design submission – Dec 2012 ERDF / DCLG Full Business Plan submission – Dec 2013 Project Contracting Date (ERDF) – March 2014 Construction begins – April 2014 Construction Ends – October 2014 All dates are provisional at present. 3.5 A different approach would be to continue Aqua Greens scheme delivery in isolation of other schemes, this would not require any partnership working with other authorities and would give full control of any schemes to HCC. Funding would be an issue, both GiA and ERDF want to see joint funding approaches and would not be receptive to a single funding bid, with no allocation in 2011/12 from GiA and ERDF dependant on match funding this approach would require input of funds from HCC to progress. 3.6 The options available to Committee are: - To note the findings of the Aqua Greens Feasibility document and to approve the progression of the Aqua Greens options in combination with ERYC schemes - To note the findings of the Aqua Greens Feasibility document and to approve the progression of the Aqua Greens options in isolation without consideration of joint options and joint funding approaches This is a non-key decision. Report Number: CDR/2011/034 4 July 2011 4. Background 4.1 The Hull City Council Surface Water Management Plan (SWMP) identified high risk surface water flooding locations across the city, it recommended development of Aqua Greens, dual purpose surface water flood storage and green space amenity sites, at Derringham and Orchard Park. Halcrow Group Limited were retained to deliver a feasibility study to develop the business case for these options. Funding has been obtained from DEFRA surface water management and Yorkshire Flood Defence Committee Local Levy grants. 4.2 Flood modelling and mapping has been undertaken at both locations to develop the findings of the SWMP, survey and site investigations have been undertaken and discussions have been held with all partners to further understand the issues during flood conditions. 4.3 Preferred options have been developed at both sites which reduce the risk of flooding in the Derringham and Orchard Park areas of the city and provide wider benefits across the administrative border to Willerby and Cottingham respectively. Both solutions are cost beneficial and would allow further funding discussions to be progressed with partners. 4.4 Funding bids have been made to DEFRA Grant in Aid (GiA, via the Environment Agency) and European Regional Development Funding (ERDF). Recommendations have been made that works progressing further to the west of the city by ERYC should be considered with Aqua Greens schemes and joint funding bids would be most likely to receive future funding allocations. This is currently being considered by both authorities. 5. Issues for Consideration Derringham 5.1 A technical note appended to this paper as Appendix B details the approaches taken within this commission, further information on the options considered is given within this note. The full report will be made available to members if required. 5.2 The proposed option is to store surface water flood flows in a terraced set of lagoons on Springhead Park Golf Course, flows would be diverted in a new dyke constructed from Well Lane at Willerby Carr Lane Primary school. Flood flows would be carried in a new dyke system to the north-west corner of the golf course to utilise the terraced storage system. 5.3 The costs of the scheme would be £2.56M providing benefits of £3.31M for Derringham and Willerby through the reduction of flood damages – a 60% optimism bias is included in the costs according to HM Treasury guidelines, all relevant HM Treasury approaches have been used throughout. The scheme has a benefit cost ratio of 1.3. Orchard Park 5.4 The hydraulic modelling confirmed that flood flows into Orchard Park were derived from the large rural areas to the north and west draining through Wanlass and Creyke Becks to the north of Cottingham, further flood flows are derived from the west of Cottingham, ERYC are currently developing a scheme to attenuate flows from the Raywell Valley. The flood storage and resultant reduction of flood levels in Orchard Park due to this work have been factored into the base case scenarios for the Orchard Park Aqua Green feasibility works. 5.5 The project team considered options, 20 options were identified, and these are discussed further in the technical note, Appendix B. 5.6 The preferred option is the diversion of Creyke and Wanlass Beck into the Beverley and Barmston Drain via Counter Dyke, attenuation is required to ensure flood flows do not present an increased flood risk to the drain during storm conditions.