Planning and Flood risk in Exeter

Flood risk in Exeter

Increasing flood risk is one of the most high-profile consequences of climate change. It is vital that flood risk is considered at an early stage in the development process.

Those properties most at risk in the city are located near the river and other watercourses, including parts of St Thomas, Exwick, St Davids, Marsh Barton and Alphington.

The links below provide important information on flood risk in Exeter and should be used to help inform planning proposals. Specifically, these links will help you to:

• Determine whether you need a Flood Risk Assessment as part of your planning application.
• Establish what flood zone your proposal is in.
• Request flood risk data, including historical flood information.
• Check for Main Rivers, Ordinary Watercourse and Flood Defences.
• Gain an understanding of surface water flow paths.

If you need a Flood Risk Assessment to accompany your planning application, you will normally need a flood risk specialist to carry it out.

Please also note that we offer a pre-application advice service if you require guidance before making a formal application.

Flood risk guidance, mapping, and data

Government guidance on the need for a Flood Risk Assessment.

Mapped flood risk from rivers, sea and estuaries (including information on flood zones and flood defences).

Mapped long term flood risk (from rivers, sea and surface water).

Historic instances of flooding.

Mapped groundwater flood risk.

South West Water Drainage and wastewater management plan.

 

Surface Water Management

All developments must have an effective and robust surface water system. This should not increase flood risk to adjacent properties or land, and where possible should make improvements to reduce the risk of flooding.

Applicants must demonstrate how surface water from the development will be disposed of in a manner that does not increase flood risk elsewhere, in accordance with Sustainable Drainage Systems (SuDS) principles. SuDS systems should be designed in accordance with local and national standards.

For householder applications

Sustainable Drainage Systems should be provided for all proposals where there is an increase in impermeable area, where surface water cannot freely drain into the ground, such as an increased area of roof, driveway or paving. The different types of features that can easily be incorporated to all properties and be used for extensions and other householder development include permeable paving, rainwater harvesting and water butts, rain gardens, green roofs, living walls, ponds, filter trenches. This is even more critical in areas at risk of flooding.

The applicant should demonstrate that its prospective surface run-off will be disposed of as high up the following hierarchy as far as possible:

Most sustainable:

• Water re-use (smart water butts, rainwater harvesting, grey flushing toilets),
• Discharge into the ground (infiltration) e.g. a soakaway; or where not reasonably practicable,
• Discharge to a surface waterbody (e.g. an ordinary watercourse); or where not reasonably practicable,
• Discharge to a surface water sewer, highway drain, or another drainage system; or where not reasonably practicable,
• Discharge to a combined sewer. (Subject to Sewerage Undertaker carrying out capacity evaluation).

Least sustainable:

• Clear evidence will be required to demonstrate why rainwater re-use or disposal in the ground can not be used for each proposal.

 

Areas with critical drainage problems

There are currently no Critical Drainage Areas within the Exeter City Council administrative area, but this is under review.

 

Other useful links

Below are some other useful links that will help ensure you have fully considered the implications of flood risk, and taken appropriate measures to reduce flood risk, for your proposed development.

Devon County Council Flood Risk Management

A useful source of advice on flood risk management, including Government/Council/landowner’s responsibilities, local flood schemes, flood history and guidance/best practice on flood resilience and management.

Sustainable Drainage Systems

All applications for major development need to incorporate Sustainable Drainage Systems. Guidance is available in this document:

Sustainable Drainage System - Guidance for Devon (2023) - Flood Risk Management

Works within or near to a watercourse

If you need to carry out work in, over, above or within 8m of a Main River or Flood Defence, then you may need to apply for a Flood Risk Activities Permit from the Environment Agency. You can use the online Flood map for planning to find out about main rivers and flood defences in your area. Further guidance on environmental permits is also available.

If you need to carry out works in an Ordinary Watercourse, then you need to apply for Land Drainage Consent from Devon County Council. You can find information on the consenting process on Devon County Council’s land drainage consent webpage.

You can also apply online for land drainage consent from Devon County Council.

Property Flood Resilience Funding Scheme

Devon County Council is committed to increasing community flood resilience in Devon. They are supported by DEFRA to deliver property flood resilience measures.