FLOODING AND COASTAL EROSION

 

 

 

464. PPG 20 Coastal Planning highlights the issue of safety and indicates that further development along the coast should not be put at risk from flooding or from erosion by the sea or from landslips and that some uses are not appropriate for coastal locations. Responsibilities for managing coastal risk are complex and involve local authorities as Maritime District Councils and Coast Protection Authorities and the Environment Agency. Shoreline Management Plans set out strategic guidance for the management of the shoreline and the East Solent Management Plan provides the shoreline management strategy relevant to Havant Borough. Policy F1 seeks to restrict new development in areas at risk from coastal processes so as to minimise risk to people and property, avoid increasing costs to the emergency services and retain the ability to implement shoreline management options.

 

465. The Proposals Map defines an Erosion Risk Area, which is derived from coastal studies, including information contained in the East Solent Shoreline Management Plan. Responsibility for safeguarding people and property from coastal risk in such areas rests with the landowner, who should seek the advice of the Council's coastal engineers regarding development proposals in this area. When submitting a planning proposal in the Erosion Risk Area, the developer will be required to demonstrate how these coastal risks have been addressed. The Planning Authority will seek the advice of the Borough Council as Coast Protection Authority and will refuse development that would undermine the implementation of the shoreline management options in the East Solent Shoreline Management Plan.

 

466. National guidance specifically on planning for tidal and fluvial (river) flood risk is contained in PPG25 Development and Flood Risk which states that precautionary principles should be followed in the determination of any planning application by the use of a sequential test founded on risk based criteria. The Proposals Map identifies a Flood Plain Area derived from the Environment Agency's indicative flood plain map (2005). This indicates the flood risk areas by defining the flood plains associated with the coast and also with watercourses designated as 'main rivers'. Information contained on the Environment Agency’s Indicative Flood Plain Maps is constantly being updated and refined by them. The Planning Authority will seek the advice of the Environment Agency on planning applications in areas at risk from coastal flooding as indicated by the coastal element of the Flood Plain Area (including in the Harbours). Their advice may mean that planning permission is refused. Developers should thus seek the advice of the Environment Agency for planning proposals, which appear to be at risk of tidal inundation as shown on the Proposals Map. When submitting an application in such an area, the developer should demonstrate how flood issues have been addressed. This will require the developer to undertake a Flood Risk Assessment in accordance with PPG25. Where additional coastal defences are required, the cost of these shall be met fully by the developer.

 

467. The Council accepts that some redevelopment and changes of use in the coastal area can be justified, particularly as some sites within and outside the built- up area are already developed, for example, the holiday camps on Hayling Island, and that applications may come forward during the Plan period. Redevelopment for appropriate uses may be allowed subject to the level of risk, the other policies in the Plan (especially those in the Countryside, Nature Conservation and Landscape chapters), and the shoreline management strategy. Permanent and temporary residential developments including caravan and camping sites will not be permitted where lives could be put at risk. PPG25 identifies classes of development, which may be acceptable in areas at risk of flooding, but developers should seek the Environment Agency's advice at an early stage. The Agency's advice may mean that proposals are not feasible because of the extra construction and flood defence costs, which will have to be borne in full by the developer.

 

 

 

 

468. PPG25 Development and Flood Risk indicates that precautionary principles should be followed in the determination of any planning application by the use of a sequential test founded on risk based criteria. It contains a presumption against certain types of development within the indicative flood plains, while identifying other classes of development that may be acceptable in areas of higher risk of flooding and generally precluding built development in functional flood plains. Policy F2 seeks to restrict development which would be at risk from, or increase the risk of river flooding so as to minimise hazards to life and property, minimise the cost of protection by the emergency services and ensure that major new flood defence infrastructure is not required.

 

469. The Proposal Map indicates the areas of flood risk as the Flood Plain Area. This was derived from the Environment Agency's Indicative Flood Plain Map of 2005, which depicts the area of the flood plains associated with the coast and with watercourses designated as "main rivers". The extent of these 'main rivers', parts of the River Ems, Lavant, Hermitage, Wallington and the Lymbourne Stream is stated in the Council's Policy Statement on Flood and Coastal. Information contained on the Environment Agency's Indicative Flood Plain maps is constantly being updated and refined by them. The Council will seek the advice of the Agency on planning applications located within or adjacent to the Flood Plain Area and/or areas where the Environment Agency knows previous flooding has occurred. The Agency's advice may mean that planning permission is refused.

 

470. The Borough Council, as the competent land drainage authority for non-main (i.e. 'ordinary') rivers, under the Land Drainage Acts 1991 & 1994, is aware that there are other watercourses, besides the 'main rivers', for which records of flooding exist. These are defined and identified as 'critical ordinary watercourses' in the Council's Policy Statement on Flood and Coastal Defence. Areas adjacent to these which flood are shown on the Proposals Map as Non-main River Flood Plain Area. Policy F2 will also apply in these areas. In the submission of a planning application affecting any of these watercourses, the developer would be required to define the extent of the flood plain by means of both catchment and topographic studies. The Planning Authority will seek the advice of the Borough's Land Drainage Section on such planning applications. Their advice may mean that planning permission is refused.

 

471. Responsibility for safeguarding people and property from flood hazard is the responsibility of the owner. Hence, developers should seek the advice of the Council and/or Environment Agency for any development proposal that appears to be located within the Flood Plain Areas indicated on the Proposals Map. Applications for development proposals in such an area should be accompanied by a Flood Risk Assessment (see PPG25), demonstrating how flood issues have been addressed. In some circumstances, developers may be required to contribute to, or fully fund, the costs of a catchment study to determine the effect of the proposal on the hydrology of the catchment area.

 

472. Development of greenfield sites will normally result in increased areas of impervious material being provided. When storms occur, this may result in a sudden discharge of rainwater into the watercourse. If the watercourse does not have sufficient storage capacity, serious flooding can result. If adequate capacity to store rainwater does not exist, or does exist but cannot be protected in future, the development must include on-site storage to allow the gradual discharge of the storm water to the river system. All new developments should reflect best practice in current drainage standards and it would be expected to incorporate an appropriately designed Sustainable Drainage System (SuDS).

 

473. Proposals to culvert rivers, streams and ditches will not usually be acceptable because they increase the likelihood of flooding. Where a crossing of a watercourse is required, this should be achieved by means of a clear span structure. Where a development proposal affects a currently culverted watercourse, the developer will be expected to investigate and, wherever possible, achieve a solution whereby the watercourse is removed from its culvert and reinstated to open channel.

 

 

 

 

 

 

474. Flood defences and coast protection works safeguard property from damage from the sea and from fluvial (watercourse) flooding. Chichester Harbour is an Area of Outstanding Natural Beauty (AONB) and other areas of the Borough have been identified as having particular landscape character. The landscape quality of these areas is to be protected. For these reasons, flood defences and coast protection works should not be alien to their surroundings and the siting, design and materials should be appropriate to the locality. Both of the Harbours are protected because of their international nature conservation importance. Nature conservation Policy NC3 and the Habitat Regulations apply to flood and coast protection works, as to other developments. Other areas of the Borough have been identified as having national or local nature conservation quality. Flood defences and coast protection works should not adversely affect this quality.

 

475. Flood defences and coast protection works, by their nature, alter the natural river and coastal processes. Their disruption is not considered appropriate unless people or properties are at risk from flooding or erosion. Adverse effects may be felt at some considerable distance from the works undertaken and may impact on the natural or the built environment or both. Developers should take these impacts into account when considering proposals for flood defence and coast protection schemes. The East Solent Shoreline Management Plan sets out the policy for managing the shoreline including that for Havant Borough. Strategy Plans indicate how these policies will be implemented. The Council will not permit flood and coast protection works that conflict with these policies or reduce the future options of operating authorities managing the shoreline.

 

476. The Government has directed that each operating authority publish a policy statement setting out how Government policy aims and objectives on Flood and Coastal Defence (sea defence and coast protection) are to be implemented in their area. The Borough has published a policy statement that fulfils this aim: Policy Statement on Flood and Coastal Defence.