Surveying the biodiversity of our waterways

In August 2022 it will be two years since the NRN initiated monthly surveys of our watercourses, led by Dr. Lucy Dickinson. The project involves monthly testing of the levels of nitrates, phosphates, dissolved oxygen and pH of the rivers, streams, ponds, and springs around Eynsham. During this time Lucy has also been involved in the Oxford Rivers project collecting samples across Oxfordshire to measure the levels of pollution from the many sewage overflows which take place regularly across the county.

There has been one piece of good news, namely the success of the application for bathing waterstatus for Port Meadow, only the second spot in England to achieve this (https://www.oxfordmail.co.uk/news/20062237.oxfords-port-meadow granted-water-bathing- status/). Sadly, this does not actually mean that the Thames reaches the required levels to be good/safe for swimming, only that the Environment Agency (rather than the team of dedicated
volunteers) is now required to monitor and report on the levels of pollution during the summer swimming season. Meanwhile, swimmers are strongly encouraged to sign up for the Twitter alerts (@OxThamesSewage) and to avoid swimming for 48 hours after a release (which definitely do not
only take place after heavy rain). More guidance on safe swimming can be found at Wild Swimming.

Of much greater importance than our safe enjoyment of the rivers is the impact that pollution, both from sewage, agriculture and household run off has on the biodiversity of our waterways, and this is something which needs further investigation. Phosphate and nitrate levels continue to be high across most of the water bodies in the catchment, and LD observed the impact this has had on the level of algae and the number of insects this year. Of particular concern are the recent readings from the Fishponds, which showed levels of 20ppm for phosphates at the start of June. This is over a hundred times higher than the level designated as highly polluted by the Freshwater Habits Trust, and may represent a real threat to the invertebrates and other species living in the ponds. To complement the ongoing monitoring of pollution, we are now going to survey and record the bugs in the water. The idea is for us to gain the skills to monitor the biodiversity of our ponds and rivers – we can’t save what we don’t measure!

This project has kicked off with our Bugs in Brooks Workshop, led by Dr. Maarten van Hardenbroek van Ammerstol of the School of Geography, Politics and Sociology at University of
Newcastle (Maarten lives in Eynsham!).

Finally, please encourage everyone enjoying the rivers to do so responsibly – take your litter home with you, and don’t disturb wildlife. Also, do think about your water use at home, including not flushing wipes down the toilet, and switching to environmentally friendly detergents etc. While it is definitely the case that the water companies and large agricultural businesses have a duty to look after the waterways, there are also many personal actions which have an impact.

Dr. Lucy Dickinson