Our Work
Riverfly Monitoring
Riverfly Monitoring
Introduction to the project
Riverfly monitoring gives an indication of a river’s health. The creatures we look for require clean well oxygenated water. Our group of volunteer monitors were trained in 2023 and began monitoring regularly at monthly intervals in January 2024.
Riverfly monitoring samples the invertebrate life within the river. These are the nymphs and larvae that as adults leave the water as flies to breed, and include groups like mayflies, caddis flies and stoneflies. There are eight species groups that are monitored, (one of these is not a fly at all!) These species are susceptible to pollution. Monitoring takes place once a month but spot checks occur when there is concern about a particular location which may have experienced pollution.
- To regularly record the riverfly in the River Sid at specific sites within the catchment
- To build up a database of records to allow for clear monitoring if things change
- To use the data to help support the local community in nurturing the river and improving and applying good land management practices. What happens on the land is reflected in the river
Project Details
This volunteer-led monitoring project helps to monitor the health of the rivers within the catchment. Once trained up, volunteers are supplied with the kit enabling them to take monthly samples, with training on the correct identification of the river invebrates.
Taking Samples at Monitoring Sites
The sample is taken by a 3-minute sweep of the river, kicking the river bed to dislodge the invertebrates, which flow down into the net.
Having taken the sample from the river, the species are placed into an observation tray which is filled with river water, and the spieces are counted. Sometimes there are hundreds of individuals, sometimes none.
A score is allocated to each species group, 0 for none present, 1 for up to 10, 2 for up to 100, 3 for up to 1000 and 4 over 1000. An average score for our river is between 10 to 12, 5 is poor and 16 excellent.
Monitoring takes place once a month at dedicated locations on this map, but we will carry out spot checks when there is concern about a particular location, which may have experienced pollution.
The Eight Species
Below are the eight river invertebrate speices we look to count and log. Occasionally, we may also come across other river inhabitants such as bullheads, a small flat fish with a large mouth (also known as Miller’s Thumb).
Flat-bodied Mayfly
Blue-Winged Olive
Stonefly
Gammarus
Mayfly
Olive
Cased Caddis Fly
Caseless Caddis Fly
The Results
The results of each monitoring session are logged with the Westcountry Rivers Trust on a platform called Cartographer. If you are a registered user you can see the entire data set for the Sid Catchment. However, The Riverfly Partnership processes the data and presents it graphically and anyone can log in and access data from all over the country. https://riverflydata.org/
Trigger Levels
The Environment Agency set a trigger level for each stretch of the river. If your score is below that level they will come an investigate for a pollution incident. The trigger level for the upper reaches in the catchment is 7 and 5 for the rest of the river.
Training and Volunteering
If you want to take part in Riverfly Monitoring, you will be teamed up with one of our trained Riverfly personnel and you can learn the ropes alongside them. Once we have enough volunteers to make an official training session viable, we will seek funding to set this in place. This would mean you would be allocated a location on the river to monitor and be able to submit your records to the data bank.
Health and Safety
There are important safety issues to be taken into account when Riverfly monitoring and we will make these clear to you if you become a volunteer. The main point is that monitoring is always done with at least two people, one on the bank the other in the river.
Survey Results
Annual riverfly monitoring results can be viewed on our Resources Page or downloaded below. You can volunteer to help with our riverfly monitoring by registering your interest on the Get Involved page.
Other Projects
Take a look at some of our other work and projects.
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