BOROUGH OF POOLE
ECONOMY AND OVERVIEW SCRUTINY COMMITTEE
4 NOVEMBER 2010
REPORT OF HEAD OF PLANNING AND REGENERATION
ON THE FLOOD RISK MANAGEMENT STRATEGY PREPARED BY ROYAL HASKONING FOR BOROUGH OF POOLE
1. Purpose
1.1 To up date EOS Members on the work undertaken by Royal Haskoning for the Borough of Poole on the future management of Flood Risk in Poole, including the potential costs of upgrading and reinforcing flood defences for the Town.
2. Recommendation
2.1 That Members acknowledge the findings of the Report.
3. Background
3.1 Following the Core Strategy Examination 2 years ago it was identified that a Flood Risk Management Strategy would be required to deliver future flood defences for the Town and to protect future development. Whilst new development need not be held up until this was in place, the FRMS would inform the Delivering Poole’s Infrastructure DPD, and therefore where and how future flood defences would be provided to protect future development (particularly in the town centre).
3.2 The study has been undertaken by consultants Royal Haskoning with input from the Environment Agency. The study area comprises the southern part of the Borough, around the coast, Harbour and Holes Bay (see map in Appendix A to this report). Based upon DEFRA sea level rise forecasts for the next 100 years the study is a strategic review of the flood risk management measures that are required now and in the future, in order to conform with the Shoreline Management Plan and the development requirements for the Borough.
4. Report Findings
4.1 The total cost of the proposed flood risk management infrastructure for the entire study area equates to a capital cost of approximately £158 million. This figure includes a 60% optimism bias which heavily weights the cost in terms of risk i.e. there is a substantial contingency included.
4.2 The Borough currently has approximately 500 properties at risk of tidal
flooding from the 1 in 200 year tidal event, and it is expected that this will increase to about 4040 properties by 2126, due to a predicted sea level rise of approximately 1.25m (based on current guidance). This demonstrates the urgent need to make provision for future defences.
4.3 Results indicate that the present value benefits for a scheme protecting up to a 200
year flood event amounts to about £157 million. The value increases significantly if
the work is undertaken at a later date, rising to £1,128 million for a scheme
constructed in 2126. This significant increase is a result of the predicted rise in sea level due to climate change, as both the number of houses affected and the depth of flooding is greater. As sea levels rise and more property becomes affected the proportional cost of undertaking the work becomes more beneficial and economically more justifiable, albeit the later it is left the greater the likely capital cost at today’s prices.
4.4 The study splits the works into various sub-cells across the Flood Risk Management Area and analyses when each individual component becomes economically viable (with some sub cells being most economically viable over the Core Strategy timeframe up to 2026). Cells 2 and 4 relate to the Regeneration sites and Cell 3 the top of Holes Bay. The following table shows the benefit cost ratio for potential flood defence scheme across the cells, and highlights that works in some cells are viable sooner than others, which will help to prioritise delivery. N.B. 1 or above is economically viable.
/ Year the scheme is undertaken /Cell / 2010 / 2035 / 2060 / 2086 / 2126 /
1 / 0.3 / 0.8 / 1.8 / 3.4 / 5.4
2 / 1.5 / 2.5 / 4.0 / 6.0 / 7.9
3 / 2.1 / 4.6 / 10.6 / 20.1 / 30.0
4 / 1.0 / 1.9 / 3.7 / 6.1 / 8.7
5 / 0.8 / 1.5 / 3.0 / 5.0 / 6.9
6 / 0.3 / 0.5 / 0.9 / 1.5 / 2.1
All cells / 1.0 / 1.8 / 3.2 / 5.2 / 7.2
4.5 The red indicates that the cost is greater than the potential benefit, orange
indicates that the benefits outweigh the cost but Defra funding is unlikely, whilst
green highlights where it may be possible to obtain Defra funding for the works.
4.6 Royal Haskoning recommend that the main focus of any funding opportunities should be directed towards cells 2 and 4 as these are thought to provide the best value for money and will allow continuing development of Poole town centre.
4.7 The various phasing and cost options in the report will inform the priorities and timings of the defence works and help the Council in establishing the funding streams to deliver them. The Delivering Poole’s Infrastructure DPD will include programme and phasing of works which will inform a CIL charging schedule. However, CIL will only be one small element of funding for infrastructure. Therefore, the Council need to be aware of the report’s conclusions and financial implications to ensure the full defence strategy is delivered corporately by 2026.
5. Conclusion
5.1 The FRMS report is a technical document that will inform future planning documents and infrastructure programmes, including Delivering Poole’s Infrastructure DPD. This will enable future flood works to be planned, funding issues addressed and implemented on and used to support the delivery of the Regeneration sites and new development in the town centre.
STEPHEN THORNE HEAD OF PLANNING AND REGENERATION
CONTACT Officer: Helen Harris Planning and Regeneration 01202 633329, email
Appendix A