Policy information sourced from the Mole Valley Local Plan

INF3: FLOOD RISK

Flood Risk Schemes
1. The Council will work with partners, in particular the Environment Agency, Surrey County Council as the Lead Local Flood Authority, the Catchment Partnership and the Surrey Flood Risk Partnership Board to manage flood risk in the District and implement schemes that mitigate risk, safeguarding land for such schemes where appropriate, whilst preventing the pollution of ground and surface water, improving water quality in rivers and streams and increasing the biodiversity of wetland habitats.

New Development and Flood Risk
2. All development will seek to avoid, reduce or mitigate flood risk by:

  • Ensuring development is directed towards areas of lowest flood risk from any source by applying the Sequential Test;
  • Following the application of the Sequential Test, using the Exception Test to determine whether the development is both justifiable on sustainability grounds and that flood risk can be managed satisfactorily, in line with national policy and guidance;
  • Undertaking site-specific Flood Risk Assessments in accordance with national policy and guidance;
  • Permitting:
    1. More vulnerable development within Flood Zone 3a only if the Exception Test has been passed; and,
    2. Essential infrastructure, only if the Exception Test has been passed and it has been designed and constructed to remain operational and safe in time of flood;
  • Avoiding development entirely in Flood Zone 3b with the exception of essential infrastructure uses provided the Exception Test has been passed and requiring both essential infrastructure and water-compatible infrastructure to be designed and constructed to:
    1. Remain operational and safe in times of flood;
    2. Result in no net loss of floodplain storage; and,
    3. Not to impede water flows or increase flood risk elsewhere.
  • Adopting flood mitigation measures that are appropriate to the source of the flooding, its frequency and its intensity;
  • Incorporating mitigation measures at an early stage in the design process, taking a sequential approach to the location of built structures within the site, designing buildings to reflect the flood risk and making space for water;
  • Incorporating long term management arrangements to ensure the longevity of mitigation measures;
  • Designing mitigation measures appropriate to the site conditions both at the time of construction and in the future by incorporating an appropriate allowance for climate change;
  • Preventing the pollution of local ecosystems and groundwater with consideration of Groundwater Protection Zones.

Sustainable Drainage Systems
3. Where feasible, sustainable drainage systems should be incorporated into (i) all major developments or (ii) developments involving a net increase of three or more dwellings or 0.25ha in size within Local Critical Drainage Areas, as identified on the Policies Map. They should:

  • Be designed as an integral part of the development;
  • Ensure that surface run-off is managed so as not to increase on- and off-site flood risk;
  • Follow the surface water hierarchy, discharging surface water to watercourses/sewers at pre-development greenfield run-off rates on all greenfield sites and brownfield sites within Areas of Critical Drainage and as close to greenfield rates as feasible in all other locations;
  • Seek opportunities to incorporate water quality, biodiversity and amenity enhancements and additional green infrastructure as part of a drainage solution; and,
  • Ensure that there is no increased risk of pollution to local ecosystems and groundwater, with consideration of Groundwater Protection Zones.

4. Sustainable drainage systems should be considered and are encouraged in all developments.

For more information please see the Mole Valley Local Plan