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Water Testing

Empowering Volunteers across the catchment to Protect Water Quality 

River Mole River Watch launched an ambitious water quality testing program across the River Mole catchment area in May 2023.


We recruited and trained a group of dedicated volunteers to take water samples, carry out testing, report their data and observations. Working with our volunteers we identified 30 suitable and safe test sites both on the main river and  the tributaries all the way from the source of the River Mole in Crawley to the confluence with the River Thames at Molesey. 


At over 80km in length and covering an area of 450 square kilometres the comprehensive coverage of our river catchment by volunteer testers is a huge early success story!

Efficient Data Collection and Analysis

To streamline data collection, we have developed a mobile survey app. Every month our volunteers record water quality test measurements and observations of river health on the app at their river test site. In addition, they record river flow and level and antecedent conditions such as weather and known pollution discharges.

The data collected from each stretch of the river is is recorded on the app. It is aggregated and analysed, providing a comprehensive overview of the entire catchment area and allowing us to see hotspots of pollution. From the data we have collected we are already seeing emerging patterns.

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Expanding the Scope of Testing 

The initial focus of the testing program lies in assessing phosphate levels using Hanna Low Range Phosphate Checkers. Phosphate is a useful indicator of pollution from agricultural and sewage treatment plants. However, we aspire to broaden testing parameters to encompass additional essential measures such as nitrates, pH, turbidity, temperature, and dissolved oxygen.


We are also working with South East Rivers Trust to develop a county-wide testing programme covering more catchments. This multifaceted approach will provide a more holistic understanding of the river health across the Mole Catchment and beyond. 

Monitoring Beyond Phosphate 

In our dedication to protecting the River Mole, volunteers go beyond phosphate test data alone. They also monitor for visible signs of pollution, such as dead fish or excessive algae growth, as well as indications of contamination through smell or plastic waste. In addition, volunteers diligently record the river level, weather conditions, and any instances of upstream sewage spills within the previous 48 hours.

Building a Foundation for Change

The first round of River Mole River Watch's water quality testing program, initiated in May 2023, will span six months of consistent monitoring and data collection. An interim meeting with volunteers and stakeholders in November will then enable us to hear feedback on observations and methods, develop new testing regimes and provide analysis of early findings.


A further 6 months of testing will follow through the winter. This will build a valuable body of evidence across at least 12 months which will be used to engage in ongoing discussions with key stakeholders such as Thames Water, the Environment Agency, farmers, and other polluters and custodians of the river.


By presenting citizen science data, River Mole River Watch aims to raise awareness, influence policies and drive positive change in river management practices. 


A Collaborative Network

River Mole River Watch exemplifies the power of citizen science and the remarkable impact that a dedicated group of individuals can have on protecting our natural resources with the help of partners such as South East Rivers Trust.


Through our water quality testing program, our wonderful volunteers are fostering a sense of environmental stewardship and initiating conversations with key stakeholders and the wider public to safeguard the River Mole's flow and ecological balance for future generations. 

If you would like to find out more about our water testing programme, or volunteer please contact us.

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