River Restoration (AQA A Level Geography)

River Restoration & Conservation

• Human activity on rivers has often been far from effective

• In the past, rivers have been straightened, deepened, diverted, dammed, altered by steel and concrete, and adapted to  reduce flooding and benefit people

• However, many of these changes had negative impacts and unforeseen consequences

  • E.g. dams have reduced flooding, improved navigation and allowed year round irrigation

  • But they also increase rates of evaporation and river erosion below the dam

  • Meander straightening on the Mississippi was only short-term as the river began meandering again and abandoned the new channels that engineers had created

• River restoration and conservation is the protection, preservation, management, or restoration of wildlife and natural resources (forests, soil, and water etc.)

• Achieved through the removal of hard-engineered adaptions to meanders, wetlands and floodplains, in order to return the river to natural flood management

• It is often difficult and impractical to do, as the built environment has be developed in response to the original changes

• As a result, most river restoration projects are only partial, but they can be successful conservation projects

Damaged Urban Catchments

Restoration of the River Cole, Birmingham 

• The River Cole in Birmingham (UK) is a tributary of the Thames river and has been heavily modified to improve its efficiency for the variety of industries in the city at various times in history

• The channel had not only been straightened and widened but also deepened to reduce the risk of flooding in recent times

• As a result of the alterations that took place, the quality of the water and biodiversity in the area has fallen significantly

• In 1995, a project was set up to restore the River Cole to its original course. The project aimed to reintroduce wildlife to the area, improve the water quality and reduce the risk of flooding by reintroducing wetland

• The project was funded by the EU, the River Restoration Centre (RRC), the Environmental Agency & The National Trust. In order to restore the original course of the River Cole, old maps of the channel were used to work out its natural course

• To recreate the course, a new channel was created that flowed 1.2m above the current channel, as the current channel had been dredged and was lower than the original

• In addition, the new channel was given meanders that were present in the past and allowed space to meander naturally

• Finally, the old channel was blocked off so that the river would flow through the newer channel

• The project appears to have been successful, as it has recreated wetlands which helps reduce the risk of flooding and has allowed the river to flood naturally, which improves the fertility of the surrounding land and prevents floods further downstream

• New wildlife and plants have started to inhabit the area surrounding the river and the surrounding environment is more pleasant

• However, the project did receive criticism as the floodplain surrounding the river is used as agricultural land and many farmers were unhappy to have marshland developing nearby

• They also were unhappy about future loss of land due to the new course the river would take and because the river would meander and take more land

• Finally, they were unhappy with allowing the river to flood naturally as while it would deposit fertile alluvium, it would also inundate and damage anything they were growing at the time