Flood advice for Land and Riparian Owners

Watercourse management

A watercourse is any channel through which water flows. The channel can be natural or man-made. It can be above or below ground and does not have to contain water all year round.  

Some watercourses are classed as Main Rivers and these are managed by the Environment Agency.  

The rest are ‘Ordinary Watercourses’ and if you have such a watercourse on or under your land then you will be responsible for its management and maintenance.

Ownership and maintenance  

The maintenance of watercourses plays a key role in flood risk management. Responsibility for the maintenance of watercourses, particularly in relation to roadside ditches, is often misunderstood.  

If someone owns land including or alongside a watercourse, then they are responsible for ensuring the flow of water through that channel. The legal term for this is ‘Riparian Ownership.’  

A watercourse needs to be kept in good order to prevent flooding. This includes maintenance of the bank and bed, as well as any trees and shrubs growing on the banks. Any debris must also be cleared by the owner of the section, even if it did not originate from their land.  

If a watercourse runs along the boundary between two neighbouring properties, each owner will be responsible for maintenance up to the centre line of the watercourse.  

Develop a Maintenance Programme  

Most watercourses will require annual maintenance. It is important to plan when and how this is done. Aspects to consider include:  

• Open Watercourses (including ditches) - How much vegetation is to be cut back? When will silt from the bottom of the ditch need to be removed and how much?  
• Piped or Culverted Sections - How often will these be inspected for signs of blockage or collapse? Will a company with specialist inspection and blockage clearing equipment be needed to do the work?
• Structures (Walls, Grilles, Screens) - How often will these be inspected and cleared to ensure they continue to do their job?

Consider the Environment  

It is important to consider any impact on wildlife when maintaining watercourses and ditches. This work should not be done during the breeding season of March to mid-July. The best time of year is late September/October, before heavy winter storms and when vegetation has naturally died back.  

It is better to carry out ‘little and often’ maintenance, using hand tools wherever possible.  

If heavy machinery is needed to clear large stretches, it is best to trim alternate banks, or different sections each year, so there is always a healthy area to which the wildlife can move.  

When mowing/trimming a fringe of vegetation should be left to maintain some habitat. Any cuttings (including grass) should be removed to avoid blocking the flow of water.  

De-silting  

The original profile of the watercourse should not be altered when de-silting, so that the overall gradient and flow patterns stay the same. This avoids adding to the flood risk upstream or downstream.  

The impacts on wildlife must be managed: silt that is dug out should be left on top of the bank for a short time, to allow wildlife to move back into the watercourse. The silt and associated vegetation must later be removed to prevent it washing back in or blocking the flow of water.  

Roadside ditches  

Many roads drain into ditches, but this does not mean they are owned by the Highway Authority. Usually, the Highway Authority only maintain the road and footway next to the ditch.  

Maintenance of most ditches will be the responsibility of the adjoining landowner. This applies even if they flow into a pipe, or culvert, underneath a driveway for example.

Consent for works  

Any work other than cleaning and general maintenance on Ordinary Watercourses requires formal Land Drainage Consent from us (the Lead Local Flood Authority).  

Find further information on Flood Risks and New Developments.

Let water flow naturally  

If any vegetation, such as trees or shrubs, is growing in or has fallen into your watercourse and is not affecting the natural flow of water, you should let it remain there as it can help to prevent flooding by varying the shape and flow of the channel, as well as reducing erosion.  

Useful Contacts  

• WNC Flood and Water Management Team: [email protected]
• Environmental Agency

Last updated 03 April 2024