Investment by UK water companies has resulted in increased biodiversity in UK rivers since 1991 including growth in numbers of freshwater invertebrates, a study has found.
Over the past 30 years a combination of investment and demarcation of sewage undertakings and the regulator means rivers are cleaner with more abundant wildlife.
That’s according to Professor Andrew Johnson from the Centre for Ecology & Hydrology who led a study into invertebrates in the River Ray in Swindon.
Professor Johnson told Utility Week there was a “virtuous circle in which some of the most unloved figures – Euro bureaucrats, government regulators and privately-owned water companies, have contributed to an environmental success story.”
Prof Johnson led a report on changing wastewater treatment types that indicates a general recovery of invertebrate populations since the implementation of the EU Urban Wastewater Treatment Directive in 1991.
When the directive first appeared it only applied to “sensitive rivers” but the government took the stance that all rivers should be covered by the directive.
“England is in a tight spot because we are densely populated and have relatively small rivers compared to other places in Europe, so British freshwater wildlife is on the front line,” Prof Johnson said.
The directive as well as private investment from the water companies has vastly improved sewage treatment and led to the abundance of freshwater invertebrates. Since privatisation the industry has had the opportunity to invest in wastewater improvements and has spent £26 billion between 1990 and 2015 according to Defra figures.
“We believe there was a general national trend for improvements in urbanised rivers that has been going on since the 1990s,” Prof Johnson said.
Prof Johnson said the challenges of a small river in a densely populated area meant that the improvements seen in the Ray were “very encouraging” for the general health of UK waterways.
“The River Ray is one of the most exposed rivers to wastewater effluent, so if we are seeing the numbers of invertebrates here it is very encouraging about the ability of British invertebrates to deal with the current range of chemicals in activated sludge plants.”
Prof Johnson led the study for The Centre for Ecology & Hydrology. The study analysed four decades of chemistry and invertebrate data from the regular monitoring of both chemicals and invertebrates in the River Ray in Wiltshire by the Environment Agency and its predecessors between 1977 and 2016.
Prof Johnson added: “The fact there has been a continual increase in biodiversity in the Ray despite it being a small river taking the entire treated wastewater of a large town of 200,000 residents is extremely encouraging. It indicates that even for rivers with a very high wastewater content their fortunes can be turned around. It is wonderful to think that people walking by the Ray are seeing returning species of damselflies and caddisflies that they weren’t seeing 30 years ago.”