Collaborating on chalk streams in the Beane

Understanding chalk streams

Chalk streams are a unique ecosystem type of river or stream that is primarily fed by underground aquifers in chalk bedrock. This water is naturally filtered through the porous chalk, resulting in exceptionally clear, clean, and mineral-rich water that provides many nutrients and a steady temperature. The unique characteristics of chalk streams support a distinctive and rich ecosystem, making them ecologically important. 

Chalk stream flows are variable. The top of chalk streams can dry out in the summer, and then re-wet in the winter, known as winterbournes. This allows for specialist species to develop in the area.

Chalk streams are rare globally, but prevalent in the UK. About 85% of chalk streams are found in the United Kingdom, with over 200 streams depending on classification. 

Gathering evidence

Mudspotter: Mudspotter was helpful in showing sediment pathways into the river in the upper catchment. Extra sediment causes inter-gravel pore spaces to clog, reducing habitat for macroinvertebrates and areas for fish to spawn.

eDNA: This method samples small fragments of DNA shed by organisms into the river as part of their life and death process. The Natural History Museum used eDNA to understand the biodiversity of the Beane River, and identified more than 130 species across the catchment. Interestingly, samples identified mammals that could be found in the area in addition to fish parasites. This information can be cross-referenced with survey data to understand if there are invasive species. For example, eDNA data were used to look at Eel populations around fish barriers and upper tributaries.

Outfall Safari: In the case study below, Outfall Safari was used to assert community concerns regarding freshwater leaks into the river and give utilities companies and the EA the exact location of the leaks to address the issue.

Learning from CaSTCo

Through CaSTCo, the Demo learnt how to use a weight of evidence approach to assess issues affecting the River Beane.

For example, looking at Nitrates, using borehole data (Affinity Water), spring data ( citizen scientists) and EA data, the Demo confirmed the aquifer water is high in nitrate before it enters the river across the catchment.

See the Beane Water Quality Data Interpretation presentation below.

Ground-truthing through community action

Ground truthing is the process of checking information found from other sources through field observation. from imagery against what’s actually on the ground. It’s not used to confirm or negate observations but rather to offer alternative information or solutions.

In the River Beane, the Environmental Agency had identified an eutrophication problem. During surveying, participants identified other issues that could be contributing to eutrophication, including agricultural runoff and increased nitrate in the groundwater. These ground truths provided additional context to the eutrophication issue, offering better information to understand what the EA needed to monitor and potential other threats.

Lessons for citizen science

• Work together: Don’t presume what citizen scientists want to learn, or what they need; instead, ask them. For example: ask what the best time to meet is, what they’re hoping to learn and what they want to do, instead of creating an agenda beforehand.
  
• Establish your goals: Decide what you want to monitor as a collective, and provide insight into why some options aren’t viable. For example, while volunteers may want to study bacteria, this may encourage more people to enter chalk streams, therefore increasing disruption and sediment load.
  
• Ask for feedback: Talk to citizen scientists regularly and take their thoughts into consideration. One opportunity for this is to display data collected back to volunteers and organise social events for community building.

Next steps for the River Beane

• Supporting farmers: The River Beane Restoration Association (RBRA) and Herts and Middlesex Wildlife Trust aim to work with the local farming group to collaborate with farmers and landholders in utilizing the data collected by the RBRA. Such outreach will highlight data collected through the project.
  
• Forward together: Following their extensive data collection, the group hopes continue the collaboration they created within the Demo. While the partners had worked together previously, the CaSTCo program brought them closer together and formed deep working relationships between the collaborators and amongst the citizen scientists.