Citizen Scientists Helping to Improve Oxfordshire's Rivers

March 2023

Eoghan Concannon - Evenlode Catchment Partnership Project Officer

Citizen Scientists volunteers have been monitoring phosphorus, nitrate, and turbidity monthly in the Evenlode catchment since 2015 using Earthwatch’s ‘FreshWater Watch’ sampling kits and uploading the data onto the online platform. The main method of river sampling used by Citizen Scientists looks at Phosphorous, Nitrogen, turbidity levels, and riverfly diversity and abundance (which is a good determinant of water and habitat quality).

Our Citizen Scientists have collected over 1000 samples on a monthly basis since 2015,

This dense database has highlighted that sewage spilling from Thames Water is the biggest pollution problem facing the Evenlode. You can see if any storm discharges are happening near you, especially after rain fall events through Thames Water’s Website at has already been 100s of hours of spilling in 2023 according to this map. In the Evenlode catchment, there was 541 spills, 7,300+ hours of sewage discharge in 2021 (Thames 21, 2023).

Presentation from the Environment Agency and how they will use Citizen Science data @Earthwatch

In an effort to halt these pollution events, Evenlode Citizen Scientists came together for a meeting in Charlbury on 4th February, with attendance from the Environment Agency and Thames Water. This was to hear what needs to be done to stop sewage pollution which the citizen science monitoring effort has highlighted distinctively. We also heard from other catchment projects around the Thames.

On the day, Earthwatch, who lead the Evenlode Catchment Partnership’s (ECP) water quality group, gave a brief on their annual report for 2022 for the Evenlode talking about their recent findings through the citizen science network and their sample collections. The Environment Agency (EA) told us how they plan to use citizen science data as an “early warning system” so the EA can come to carry out their own investigations. However, some may ask why this hasn’t been done appropriately to date, as this is not a new problem. Thames Water encouraged attendees to keep sending their data and concerns to them as this will help drive change.

Other Catchment Partnerships are also facing challenges

Thames 21, who host the Oxford Rivers Project, have been carrying out investigations in the lower Evenlode and Windrush catchment looking at how much bacteria is entering rivers in the area.  “Bacteria in rivers is not monitored as standard by regulatory bodies” (Thames 21, 2023). Their work highlighted that “Only 1 site of the 8 recreational sites would pass bathing water status standards. The other 7 sites had between 1.5 - 3 times the safe level” (Thames 21, 2023).  This is concerning because  part bathing water status has been granted in Oxford recently for Port Meadow.

Figure 1) The health of rivers around Oxford from Thames 21

Update from Claire Robertson (Thames 21) on the Oxford Rivers Project

The Crane Catchment has been working on an initiative called Citizen Crane since 2014. The Citizen Crane project combines Riverfly Monitoring Initiative (RMI) surveys with water quality monitoring and empowers communities to gather the right evidence to improve an urban river.

The Citizen Crane teams collect RMI data every month from 12 sites across the catchment; produce regular reports that bring together the findings from these activities; and provide a baseline condition assessment for the SWC. Their “Outfall Safari” initiative aims are to:

1. Systematically inspect and record outfalls

2. Assess and report pollution

3. Build evidence of the scale of the problem

4. Raise awareness

Presentation from the Crane Valley Partnership @EarthWatch

The Chess Catchment

The Chess Catchment organise Citizen Science Surveys through MudSpotter and the Modular River Survey (MoRPH). Mud-Spotter is an investigative survey that monitors riverbanks for possible sources of sediment input. It is conducted (ideally) within 24 hours of rainfall event and aims to establish possible sources of sediment input during dry periods. Modular Morph surveys are done as a technique to identify habitat quality and ecological indicators of river health. It is being used to assess whether restoration work has improved biodiversity and hydromorphological function of the River Chess. A mobile phone app is under development.

Presentation from the Chess catchment

Citizen Science Workshop at the Evenlode Catchment

We ran a workshop to enable our citizen scientists to network, share stories and ideas and also to discuss the challenges and questions we all have in the fight against water pollution.

“It was really useful to do the training session in-person on Charlbury bridge. Otherwise, we wouldn’t know what we’re doing. It inspired us.”

Citizen Scientists are eager to fill data gaps and would welcome direction on interesting under-monitored areas. The Glyme has relatively few Sewage Treatment Works (STW), and STW with tertiary water treatment, making for interesting research questions.

The impact of STWs is well-known, ECP Citizen Scientists have called for action, but there is a noted impression that those statutory bodies are not meeting their obligations to a satisfactory level. Enforcement mechanisms were discussed to penalize pollution to those relevant in the water industry. To reduce the stress on STW, citizen scientists would like to see ideas about rethinking and replacing current STW processes and operations to build a nature-friendly solution.

What the Citizen Scientists need

  • Legislation change from the Environment act – more investment to uphold water regulations.  
  • More legal penalties on water companies i.e. Strict regulations, effective permits, EA or third party to monitor Thames Water's assets and outputs i.e. "no more marking your own homework!"
  • Investment from water companies to stop sewage pollution - i.e. Stop Thames Water paying their shareholders dividends; enable system changes to the water industry; Upgrade of Sewage Treatment Works capacity
  • To Learn good practice from other catchments and countries

What you can do to help


It was incredibly inspiring to be around so many individuals giving up their time in the quest to make our rivers cleaner and safer. The scale of the environmental issues we all face daily can seem immense and out of our control. Yet, there is hope – globally and locally – when people decide to take action. You can join our Citizen Scientists or find out more about water quality monitoring and its importance here: Citizen science(

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