The Changing Approach to River Management by RB

The Changing Approach to River Management by RB
March 2, 2022 Adrian Walters

The names may have sounded unassuming but storms Dudley, Eunice and Franklyn caused their fair share of upheaval as they blew through Sudbury in mid-February.

The damage caused by the high winds has been clear to see on the common lands. A number of riverside willows and alders have blown down – in some cases they lay across the water, semi-submerged – their branches causing sizeable obstructions on the Stour’s journey through the water meadows.

In years gone by these trees would have been removed from the water course by workers from the Environment Agency or its forerunner body, the National Rivers Authority. Today, only the largest trees are likely to be dismantled.

Channel management

Go back 30 years and these organisations were responsible for all main river channel management works in Sudbury including cutting reed and vegetation; the trimming of herbaceous and woody material on the banks and the dredging of river channels when necessary. But, as the years have passed, EA funding has been reduced and cuts implemented, and today with the key focus being preventing flooding, virtually all management work has ceased. Today, the Agency’s policy regarding a build-up of trees, debris and encroaching vegetation in rivers is to let nature take its course.

The only occasions the EA is likely to do work on the Stour around Sudbury will be for low-level maintenance of the Navigation where necessary for boating interests, flood defence, and habitat enhancement for conservation and fishing, rather than for the traditional management that was undertaken in the past.

This state of affairs has caused several people to get in touch with the Sudbury Common Lands Charity to bemoan what they see as neglect of our river. Of course, the state of the river is a matter of perception. Where some see blockages and untidiness, others see more wild areas and improved habitats for wildlife.

EA surveys now show increased numbers of fish because the habitat has improved in terms of places for them to spawn and increased cover from predators. In turn, this has encouraged the otters to return, and we have three fully-grown pups on the river at present. However, without the EA’s intervention, the river has most certainly changed, and it will continue to do so. For people who remember it as a managed river, this may come as a shock.

Dredging

 When it comes to river management, the subject of dredging stirs strong feelings.

Dredging and desilting are methods used to remove an accumulation of silt material and historically they have been carried out for a broad range of reasons: to drain land, maintain flows to mills, abstract sand or gravel for construction or to improve navigation, in addition to preventing flooding.

An insight into the EA’s current attitude to dredging could be found in a blog the organisation published at the end of last year. The Agency said that dredging is not as effective at reducing flood risk as other options, is often expensive and can be harmful to the environment.  Therefore, the level of dredging and desilting has decreased in the UK over recent decades.

The EA says dredging can have serious and long-lasting negative impacts on the environment. For example, it can damage or destroy fish spawning grounds and make river banks unstable. Silt can become suspended in the water, lowering oxygen levels, potentially releasing harmful chemicals that may be present. This, in turn, impacts on wildlife, and water quality downstream.

River catchments

Taking action across entire river catchments is a much more effective and efficient way to protect communities and increase their resilience to flooding, according to the EA.

The most visible measures related to this approach include flood walls, embankments, and demountable and temporary barriers, which help to contain water within river channels.

Communities are also being increasingly protected by other flood risk measures such as storing water upstream and slowing the flow through natural flood management measures such as leaky dams.

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