DEV37 - Managing flood risk and water quality impacts

This policy is currently going through formal consultation. Click here to go to comment.

The LPAs will assist the Lead Local Flood Authority in the management of flood risk and water pollution within the Plan Area by directing development away from areas at highest risk, but where development is necessary ensuring that it is safe without increasing flood risk and pollution elsewhere. Specific provisions include:

1.     In respect of development of sites not provided for in this plan, a sequential approach will be used in areas known to be at risk from any form of flooding. Development will be resisted if there are reasonably available sites appropriate for the proposed development in areas with a lower probability of flooding.

2.     Where it is not possible for the development to be located in zones with a lower probability of flooding, an Exception Test must be undertaken to demonstrate that:

i.      There are overriding sustainability benefits to the community to be gained from allowing the development.

ii.     The development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall. This must be demonstrated through a site-specific flood risk assessment. 

3.     Development proposals at sites which fall into Flood Zones 2 or 3 (in whole or in part) should:

i.      Be supported by a comprehensive and deliverable strategy to minimise flood risk.

ii.     Be resilient to flooding through design and layout, incorporating sensitively designed mitigation measures. These may take the form of on-site flood defence works and/or a contribution towards, or a commitment to undertake such off-site measures as may be necessary to meet required flood protection standards, for example, as set out in the Local Flood Risk Management Strategy.

iii.    Provide sufficient space for drainage and flood alleviation schemes.

4.     Development should incorporate sustainable water management measures to reduce water use, and increase its reuse, minimise surface water run-off, and ensure that it does not increase flood risks or impact water quality elsewhere, in compliance with the Local Flood Risk Management Plan and national standards for sustainable urban drainage systems. Surface water from proposed developments should be discharged in a separate surfacewater drainage system which should be discharged according to the following hierarchy: 

i.      Discharge to a waterbody (if available and with sufficient capacity).

ii.     Infiltration

iii.    Discharge to a surface water sewer, highway drain or culverted watercourse with attenuation as required.

iv.   In exceptional circumstances, discharge to a combined sewer.

5.     Proposals for discharges of surface water direct to coastal waters must include measures to remove particulate and dissolved pollutants in order to conserve the quality of coastal environments.

6.     Developments which undermine the role of undeveloped estuarine coastal margins in providing resilience to climate change will not be allowed.

7.     Developments located within the Critical Drainage Area should include a Drainage Strategy setting out and justifying the option(s) proposed, present supporting evidence, and include proposals for long term maintenance and management

8.     Development will not be permitted without confirmation that sewage / wastewater treatment facilities can accommodate or be improved to accommodate the new development, in advance of the development taking place.

9.     Where necessary, financial contributions will be sought for the maintenance and improvement of drainage infrastructure, fluvial and tidal flood defences, and erosion defences. Development should provide financial contributions, as necessary, to mitigate impacts on sewer network and to ensure no adverse effect on the integrity of any designated sites.