EU regulations on dredging did not cause recent flooding

A Facebook post claiming that recent floods in the UK were because the EU does not allow dredging has been shared numerous times on Facebook and Twitter. 

Dredging is the process of removing silt, mud, and other debris at the bottom of bodies of water. This creates more space and in theory, this means when an area experiences heavy rainfall, there is greater capacity to accommodate it. 

The European Commission has said more than once that EU law “does not ban dredging”, and the fact that it isn’t banned can be seen from the fact that dredging is still carried out in the UK. 

However, some EU regulations can affect dredging decisions. For example, the EU Water Framework Directive affects elements of dredging such as evaluation as to whether dredging activities could affect wildlife. The Waste Framework Directive, meanwhile, has effects on how the silt is disposed of. A report from the dredging industry (written prior to the Water Framework Directive’s implementation) suggested these considerations do have an impact, but that overall much depends on how individual EU member states implement the directives. 

Beyond this, it is far from clear that dredging would be a solution to much of the flooding seen in recent years.

In a blog post for the Environment Agency last week, the Director of Policy for the Chartered Institution of Water and Environmental Management (CIWEM) said that dredging can help in some situations—for example on the Somerset Levels (although more dredging would not have fully prevented the floods the Levels saw in 2013 and 2014).

However, he said that for most areas where flooding has occurred, dredging would not be effective, as the floods come from fast-flowing rivers where sediment build-up is less of an issue.

In a 2014 report on the issue, CIWEM noted that dredging rivers can even increase the flood risk for communities downstream, by “speeding up the movement of floodwater through the river and drainage network”. It can also cause greater erosion of river banks, which “can be a major hazard for infrastructure such as bridges”.

It wrote that “claims that the widespread use of dredging can act as a flood prevention measure are not only unsupported by both science and evidence, they are a cruel offer of false hope to those living in flood-prone communities.” 

Or, as Professor David Demeritt, a professor of geography at King’s College London told Countryfile last week, “There has been an awful lot of garbage, if not factual untruths about dredging… it won’t make any difference with really heavy rain. If you dredge, the water ends up in someone else’s kitchen downstream, more quickly.”

So it’s not true that EU law bans dredging, although it’s fair to say that some EU rules can affect dredging decisions. And it’s not true that dredging could have prevented much of the recent flooding—potentially, in some cases, it could have made it worse.