Rivers run under your feet
By Tom Walmsley
Tiny, trickling streams, meandering rivers, gushing waterfalls and vast estuaries represent just some of the diversity of our natural watercourses in the UK and around the world.
With such variety in shape and size along their course, rivers and streams provide shelter and feeding opportunities for a wide range of plants and animals. Deep pools are important for fish and kingfishers, shingle beds are important for insect larvae and the banks are usually overgrown with wild flowers, in turn offering a food source for butterflies and damselflies and ground cover for small mammals.
They also act as ‘corridors’ for animals and plant seeds to move between habitats which have been fragmented, often by man as a result of changes to land use.
Britain is a relatively small Island and its longest river, the River Severn, is just 220 miles long entering the Atlantic Ocean near Bristol. The River Fleet is the largest of London’s subterranean rivers, running under Fleet Street on its 4 mile journey to the River Thames. Its headwaters are two streams on Hampstead Heath, each of which was dammed into a series of ponds in the 18th century. At the southern edge of Hampstead Heath these descend underground as sewers and join in Camden Town.
In a survey of the world’s 50 largest river basins, links have been found between the declining health of the largest rivers and the dams that break up their natural cycles. Almost 6,000 dams were sited out of the estimated 50,000 that exist in all rivers on earth. The study found correlations between fragmentation by dams and poor water quality, mercury concentrations, sedimentation, thermal pollution and declining biodiversity.
Of the world’s great rivers those highlighted as the most pristine and most in need of protection included the Amazon, Tocantins and Ayeyarwaddy.
British Rivers have received more attention and protection in the last decade than in the last century. Legislation has been put in place to stop industrial processes using rivers as a waste disposal system and anybody causing accidental damage is liable but the aquatic habitats cannot easily be rebuilt. The Environment Agency is in charge even though they are not well armed to enforce the law. Public engagement with rivers is on the increase though, through fishing, canoeing and wild swimming, which is raising awareness of the ups and downs of these meandering ecosystems.
See more pictures of rivers here.