Urban rivers come back to life
The water quality and wildlife in urban rivers in England and Wales have improved dramatically over the last 20 years according to a new study.
The River Wandle.
Decades of pollution, typically from poorly treated sewage and industrial waste, have had a devastating effect on our urban rivers, but these waterways are now regaining insects such as mayflies and stoneflies that are typical of healthy waters – fast-flowing and oxygen rich. The range of invertebrates found has also increased by around 20%.
The conclusions are drawn from one the largest studies of national trends in river health ever undertaken. Researchers from Cardiff University's School of Biosciences carried out an independent analysis of Environment Agency data, using almost 50,000 samples from thousands of rural and urban locations.
The team puts the general improvement down to industrial decline, tighter regulation and improved wastewater treatment over recent decades – although rivers in some rural upland areas appeared to have deteriorated slightly.
Another important finding was that drought years reversed the recovery, at least temporarily.
The research is published in Global Change Biology: here's the abstract.
Posted on 2 July 2012
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