Citizen Science: the Great UK WaterBlitz

Earlier this year two of our members took part in a citizen science project to test water quality in some of Lewisham’s waterways.  Here they describe their experience and the national results of the project.  Another ‘WaterBlitz’ will take place in September 2025, so if you would like to join them on their next expedition, please get in touch via email@foresthillsociety.com

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In early March we signed up for this national citizen science project to test local water quality over a weekend at the end of April. Citizen science is a way of actively involving non-scientists in scientific research; in this case it was organised by Earthwatch Europe to collect water quality data using volunteers, on a scale far higher than scientists could manage on their own.

The project aims to establish a comprehensive and dynamic picture of the nation’s freshwater health, enabling the identification of pollution hotspots, tracking changes over time, and providing vital data to advocate for stronger environmental policies. 

Applying for 5 testing kits, we planned on testing some of our local Lewisham waterways, all of which in the end drain into the Thames. On a hot and sunny weekend, we used our 5 phosphate and nitrate testing kits in local parks using samples taken from the River Ravensbourne, Pool River, River Quaggy, Chaffinch Brook and The Beck over the appointed weekend of 25-28 April.

Map adapted from Quaggy Waterways Action Group

Having selected the target waterways and how to access them, the process was quite simple. Gathering a water sample into a clean jar was easy without getting feet wet, though one case involved dangling the jar on a long piece of string from a bridge. Then we mixed a small measured sample into a test tube. After a few minutes wait, the colour of the result was matched against the colour charts provided to give a reading. We fed readings into the phone app immediately including a photo showing the view of the river upstream. We also filled in a few questions for each sample explaining the type of waterway, nearby vegetation and land use and any other information we felt relevant. With a pinpoint on an online map to show each sample location the upload of our 10 readings was done.

Testing a water sample from the Quaggy River

Spring Great UK WaterBlitz received over 4,000 data points from nearly 8,000 citizen scientists across the UK. Among other things  they found that:

• 66% of datapoints across the UK show poor water quality, with unacceptable levels of nutrient pollution;

• Over three WaterBlitzes, England has the worst water quality in the UK - this April, 74% of sites tested had unacceptable levels of nutrient pollution;

• The Thames and Anglian river basin districts have the worst water quality in the UK, with 86% of measurements showing unacceptable levels of nutrient pollution;

• The Scottish counties of Roxburgh, Ettrick and Lauderdale, Ross and Cromarty, Kirkcudbrightshire and Inverness have the best water quality in the UK;

• 24% of datapoints across the UK show E. coli levels that would classify as poor (were the site to be given bathing water status) with significant regional variation.

 You can explore the results further in the Great UK WaterBlitz report:

Link to Great UK WaterBlitz Spring Report

Read the report

The next WaterBlitz will be in September 2025. We plan to repeat the process on behalf of the Forest Hill Society - other members are welcome to join us now that we know how it works, it was fun to do and a pleasant way of getting around five of our lovely local parks too.