Constructed wetlands for slowing and storing water

Wetlands constructed to store surface water can reduce local flood risk or make water available during periods of dry weather. They can also help slow down the progress of run-off across the land, down tracks or from the rooves of buildings. By slowing and storing water they may also improve water quality and provide biodiversity and habitat creation benefits.

If your constructed wetland is to slow and / or store rainwater with a variable and intermittent flow, you do not need to apply for an Environmental Permit.

Find out if your wetland will be near a protected area

Wetlands designed to control water flow must not increase the risk of flooding or coastal inundation.

Protected sites

In a site designated for nature conservation or geological protection, constructed wetlands must not negatively impact the protected features, or must be shown to have a significant net benefit for the features. This may require an assessment such as Habitats Regulations Assessment (HRA) or SSSI Consent.

Constructed wetlands for the purpose of flow control in a Source Protection Zone (areas protected as sources of drinking water) must not cause a risk of contamination to the water supplies.

Drainage of run-off

They must not receive water from the roof of any building housing livestock with roof vents or from tracks used by livestock.

As part of a sustainable drainage system they must comply with the statutory national standards.

Download advice on sustainable drainage systems from the Welsh Government

Download information on rural sustainable drainage options from the Environment Agency

Flood management

If the wetland is a natural flood management feature, you must comply with the relevant guidance from CIRIA. Other permissions may be required, for example a  Flood Risk Activity Permit (FRAP).

Read the CIRIA (Construction Industry Research and Industry Association) Natural Flood Management Manual to learn about how constructed wetlands and other actions can manage flood risk.

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