Help clean our rivers

Will Blake from the University of Plymouth University, who is a Professor of River Catchment Science, is making a concentrated effort to bring more public and government attention to our rivers.

Even if the river looks healthy, what lurks beneath can be problematic. His research is aimed to gather important knowledge. If the sediment levels are too high, it can have a detrimental impact on the ecology.

Under normal flow conditions the water needs to be moving through the gravel so whatever is living in the gravel, be it salmon eggs or trout eggs, can get nutrients and oxygen from the water flow (vs stagnant water). A sign of a healthy gravel bed is one where water can freely flow through.

Will’s DIY gravel sediment assessment kit includes:

• A power paint stirrer
• A bin without a bottom
• A bunch of bottles

If we stir the beds up with our feet, we can see the sediment moving so it’s very hard to measure. Will uses a bottomless bin, wedged into the riverbed, to create a test bed, which he then stirs up. This gives a more accurate sample because it will trap the sediment. The paint stirrer is used to really aggravate the bed. Once the gravel has fallen back to the bottom, suspended sediment can be sampled by collecting it in bottles. It’ll then be analysed in a lab to see how much sediment is in ½ litre and then it's scaled up.

The sediment is essentially mud and soil coming into the river. One thing Will and his team test are agricultural chemicals like phosphorous or industrial pollutants like metal from mining.

You can get involved to help build up a picture of your local river’s health by volunteering as a Citizen Scientist. The data gathered by Citizen Scientists helps to make a case to lobby for greater legal protection.