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

To ask His Majesty's Government what assessment they have made of the effectiveness of dredging rivers and waterways while balancing environmental and habitat considerations; and, in particular, what assessment they have made of how effective this would be for the River Trent.

The Environment Agency undertakes dredging (for more information see the Environment Agency Blog on GOV.UK) to manage flood risk where it is technically effective, does not significantly increase flood risk for others downstream, and is environmentally acceptable. The effectiveness of such work in managing flood risk varies substantially from site to site. The Environment Agency makes a local assessment working in close consultation with local communities.

Historical records and modelling show that in some locations dredging can increase erosion and flood risk for communities downstream and damage wildlife and ecosystems. The Water Environment Regulations 2017 requires Risk Management Authorities to consider the impact of dredging on the ecological health of rivers but does not prevent dredging where it effectively protects people and property.

Along the River Trent, dredging is not cost effective as it would only provide a temporary and minimal increase in capacity as natural processes would cause silt to return and accumulate quickly. Additionally, there is the potential for negative impacts on the ecosystem if dredging is carried out. Many communities along the river Trent are well protected through other means such as flood defenses and other river maintenance activities which are more viable and cost effective in the long term.