Policy SE 13: Flood Risk and Water Management
Developments must integrate measures for sustainable water management to reduce flood risk, avoid an adverse impact on water quality and quantity within the borough and provide opportunities to enhance biodiversity, health and recreation, in line with national guidance, by ensuring that:
- All development follows the sequential approach to determining the suitability of land for development, direct new development to areas at lowest risk of flooding and where necessary apply the exception test; this should take into account all sources of flooding identified in the Cheshire East SFRA.
- All planning applications for development at risk of flooding are supported by an appropriate Flood Risk Assessment (FRA) to demonstrate that development proposals will not increase flood risk on site or elsewhere and opportunities to reduce the risk of flooding are sought, taking into account the impacts of Climate Change in line with the Cheshire East SFRA. New development will be required to include or contribute to flood mitigation, compensation and / or protection measures, where necessary, to manage flood risk associated with or caused by the development.
- New development is designed to be safe, taking into account the lifetime of the development, and the need to adapt to climate change.
- All developments, including changes to existing buildings, seeks improvements to the current surface water drainage network and be designed to manage surface water. This should include appropriate sustainable drainage systems (SuDS) and green infrastructure to store, convey and treat surface water prior to discharge with the aim of achieving a reduction in the existing runoff rate, but must not result in an increase in runoff. It is not sustainable to dispose of surface water via the public sewer systems; applicants seeking to drain to the public sewers must demonstrate there are no other more sustainable viable options. Where appropriate, opportunities to open existing culverts should be identified.
- Where water infrastructure capacity is an issue, all major development must demonstrate that there is adequate infrastructure in place to serve the development.
- New development enhances and protects surface and ground water quality and complies with the Water Framework Directive in ensuring that development does not cause a deterioration in the status of inland waters, unless suitable mitigation measures are in place; and
- New development incorporates water efficiency measures.
13.143 The Cheshire East area predominantly covers the Cheshire Plain, a flat, lowland area, which is characterised by watercourses running in well-defined floodplains and localised areas of hilly terrain. To the northeast, this includes part of the western Peak District, an upland area forming the southern end of the Pennines. This area has steep topography, and is characterised by steep sided valleys and large numbers of minor watercourses.
13.144 The main source of flood risk in Cheshire East is from main rivers and Ordinary Watercourses. Whilst the overall level of risk from these sources is low, there are principal town centres such as Crewe, Macclesfield and in Key Service Centres such as Congleton, where risk is greater due to the presence of a densely urban population. In these urban areas, watercourses can often be modified with straightened and culverted sections, especially where rivers flow underneath major railway and road infrastructure.
13.145 Cheshire East Council (CEC) published the Cheshire East Level 1 Surface Water Management Plan (SWMP) in July 2012. The SWMP project brought together existing flood risk information from CEC, the Environment Agency and United Utilities to assess the surface water flood risk across the study area, first through a strategic review of flood risk and then an assessment of particular sites potentially at high risk from flooding. The strategic review of flood risk across the study area has indicated that the overall level of surface water flood risk is moderate. In particular:
- Due to the flat nature of the topography, there is likely to be extensive surface water flooding resulting from an extreme rainfall event. This flooding is unlikely to be deep or fast flowing, except in localised areas, and only small numbers of properties are likely to be affected.
- Deep flooding is only likely to be experienced where there are localised low-points, such as natural closed depressions, or man-made features, for example underground car parks or subways.
- In a small number of locations, steep topography is likely to result in surface water flooding along well defined flow-paths. Flooding in these areas has the potential to represent a significant hazard to people due to its velocity and depth.
- There are likely to be a number of locations throughout the study area where surface water and fluvial flooding mechanisms are likely to interact. In these areas, it may be difficult to identify the exact source of any flooding, and CEC and the Environment Agency will have to work together to manage these issues.
- There are a large number of Ordinary Watercourses within the study area, some of which run through urban areas. In many cases, these watercourses have been culverted over and are likely to be in poor condition. A blockage or collapse of one of these culverts could represent a significant flood risk to adjacent properties.
13.146 As a local planning authority, Cheshire East Council should use the flood risk evidence collected through the SFRA and SWMP to avoid inappropriate development in areas at risk of flooding by directing development away from areas at highest risk, but where development is necessary, making it safe without increasing flood risk elsewhere. This should be carried out through the planning process, specifically during the development of the Local Plan.
13.147 The NPPF also states that Local Plans should 'take account of climate change over the longer term, including factors such as flood risk, coastal change, water supply and changes to biodiversity and landscape'.
13.148 As a Lead Local Flood Authority (LLFA) the council has a number of roles and responsibilities within local flood risk management as required under the Flood Risk Regulations 2009 and the Flood and Water Management Act 2010.
13.149 The Flood Risk Regulations require the Council to develop a Preliminary Flood Risk Assessment (PFRA). The Cheshire East PFRA was published in June 2011. The PFRA did not identify a Flood Risk Area using the national significant thresholds set by Defra. As a result, the next stages of the PFRA process, the requirement to develop flood risk hazard mapping and Flood Risk Management Plans, do not apply to Cheshire East Council. However, the Environment Agency is currently in the process of updating their national Flood Map for Surface Water (uFMfSW), which is expected to meet the requirements for flood risk hazard mapping and will be available to Cheshire East Council later in 2013.
13.150 Under the Flood and Water Management Act, Cheshire East, as the LLFA, has responsibility for developing a Local Flood Risk Management Strategy (LFRMS) for their area covering local sources of flooding. The local strategy produced must be consistent with the national strategy. It will set out the local organisations with responsibility for flood risk in the area, partnership arrangements to ensure co-ordination between these, an assessment of the flood risk and plans and actions for managing the risk. The strategy will outline how the council intends to deliver its remaining duties under the Act. The council now has additional permissive powers of control over ordinary watercourses to help manage flood risk across the borough (notably new regulatory duties under Land Drainage Act 1991 and any associated Byelaws currently being considered).
13.151 The Cheshire East LFRMS is currently being prepared and the findings of the Cheshire East SFRA and the Cheshire East SWMP should help inform its development.
13.152 Wider national policy contained within Catchment Flood Management Plans (CFMPs) and River Basin Management Plans (RBMPs) should also influence how flood risk is managed at a local level.
13.153 A CFMP provides a detailed overview of flood risk from multiple sources and policies for long-term management of flood risk within the catchment that take into account the likely impacts of climate change, the effects of land use and land management, deliver multiple benefits and contribute towards sustainable development. This is critical when areas under development pressure coincide with high flood risk.
13.154 Chosen policies and actions can be used to influence the location of development. Development should be focused towards the more 'sustainable' areas in terms of lower risk of flooding or where flood risk management is considered viable within the short and long-term plans. Development should be avoided in those areas where it is deemed inappropriate, to reduce flood risk now and in the future. Therefore, development should not rely on the future policy direction, as Environment Agency led Flood Risk Management infrastructure investment is not there to support future development, but rather to protect current properties and people at risk. Where development is planned in high risk areas, private (developer) funding will be required to reduce risk. In this instance, development may not be viable. Cheshire East is located in two CFMP catchments; the Upper Mersey and the Weaver Gowy.
13.155 The Water Framework Directive (WFD) is to deliver improvements across Europe in the management of water quality and water resources as well as improving the physical state of water courses and improving in-channel habitat. The WFD requires all inland and coastal waters to reach “good ecological status” by 2015 through a catchment-based system of River Basin Management Plans (RBMPs). The Water Environment Regulations (2003) transposed the WFD into law in England and Wales and the Environment Agency is leading on its delivery.
13.156 Cheshire East is within the North West River Basin District and the Environment Agency published the final North West River Basin Management Plan in December 2009. The main responsibility for the council is to work with the Environment Agency to develop links between river basin management planning and the development of Local Authority plans, policies and assessments. In particular, the programme of actions (measures) within the River Basin Management Plan highlights the need for: Water Cycle Strategies, Considering the WFD objectives (achieving good status or potential as appropriate) in the spatial planning process, including LDDs and Sustainable Community Strategies, and Promoting the use of Sustainable Drainage Systems (SuDS) in new development.
13.157 Cheshire East Council has set up strategic partnerships with Cheshire West and Chester Council, Warrington BC, Halton BC and St Helens BC. The Cheshire and Mid Mersey Partnership Group also serves to ensure consistency amongst the councils in their approach to water management issues.
13.158 New development should incorporate water efficiency measures as much as is practicable. Standards of water efficiency for residential and commercial development will be further defined at Site Allocations and Development Policies stage.
- Cheshire East Strategic Flood Risk Assessment
- Cheshire East Preliminary Flood Risk Assessment
- Cheshire East Surface Water Management Plan
- Water Environment (Water Framework Directive) (England and Wales) Regulations 2003
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