Skip to main content

The charity making life better by water

Water levels and flood risk

It’s strongly recommended that you contact the Environment Agency (EA) to establish initial considerations, including advice on whether it’s in the flood plain and any other water level or drainage issues.

This can be done using a Pre-Application Form (see link below) to ensure that all relevant information is available for the EA to assess.

Local Planning Authorities (LPAs) in England have to consult with the EA on most development proposals at risk from flooding. Planning Policy Statement 25 (PPS 25) 'Development and Flood Risk' and its associated Practice Guide set out government policy and advice on the subject.

LPAs in Wales are advised to consult the EA on development proposals that are at risk from flooding through the Welsh Assembly's Technical Advice Note 15 (TAN 15) 'Development and Flood Risk'.

The EA provide technical advice to LPAs and developers on how best to avoid, manage and reduce the adverse impacts of flooding.

You should also discuss any flooding issues with us, as there may be impacts on canal infrastructure. We generlaly don't encourage discharges of surface water from rainfall events to the proposed marina basin or adjacent canal. This is because these flows occur when the canal system is already dealing with high flows. However, if you wish to make a proposal to discharge surface water from your site, either into the proposed basin or into our waterway, it will require our consent.

Although typically much less variable than river navigations, which can have very considerable level changes over short periods, canal water levels can still vary, sometimes quite rapidly. The range of level variation will be dependent on a number of factors, such as length of pound, proximity to controlled and uncontrolled inflows, amount that upstream and downstream locks are being used, navigable depth in relation to pound datum, and canal freeboard, to name a few.

Most canal water levels are managed around a normal operating zone (NOZ) which is typically +/- 200mm, but water levels outside of the NOZ may be experienced at times. The design of your marina will need to take account of reasonably foreseeable water level variations to ensure safe access to and egress from moored boats. Solutions include floating, rather than fixed, pontoons. Please seek advice from the relevant Technical Manager for specific information on the likely range of water level variation at your proposed marina location, whether on a canal or river navigation, to assist appropriate design.

Please note that if you are proposing to include a dry dock as part of the marina, any transfer of water from the dry dock to other inland waters would be classed as an abstraction and would require a licence under the Water Act.

Surface water discharge
Refer to surface water discharge section on the New marina legal agreements page

General EA Development and Flood Risk information

Planning Policy Statement 25 - 'Development and Flood Risk' (PPS 25)

Practice Guide on PPS 25 - 'Development and Flood Risk'

Developments in Wales - Technical Advice Note 15 - 'Development and Flood Risk' (TAN 15)

Flood Map (enter postcode in box on right hand side of the website page)

Environment Agency Pre-Application Enquiry form

Last Edited: 11 June 2024

photo of a location on the canals
newsletter logo

Stay connected

Sign up to our monthly newsletter and be the first to hear about campaigns, upcoming events and fundraising inspiration