Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what recent assessment he has made of the effectiveness of river dredging to remove silt and reduce the incidence of flooding; and if he will make a statement.

Dredging is an important part of the Environment Agency’s (EA) annual river maintenance programme. The Environment Agency assesses each situation individually and will dredge when it is the right solution to reduce flood risk and provides long-term value for money.

The Environment Agency carried out a comprehensive series of trials in 2010 to review and update evidence on the benefits and effectiveness of dredging as one method for keeping rivers flowing freely. The trials showed that dredging can reduce flood risk, but its effectiveness and value-for-money varies significantly depending upon the location.

In many cases, dredging isn’t the best long-term solution because rivers can quickly silt-up again and other measures such as building walls or storage upstream may be more effective. It can even increase flood risk and erosion and alter the ecosystem and wildlife. Dredging is unlikely to be effective in isolation but it can be part of a solution involving multiple interventions.