South East Rivers Trust (& the Wandle Trust)

Official Launch – Riverfly Results Hub


We’re proud to announce the launch of our Riverfly Monitoring Hub for the Hogsmill river. Check out the amazing results collected by our volunteers since 2014 HERE!

Read on to find out more about Riverfly and our monitoring on the Hogsmill.


What is Riverfly Monitoring?

The Riverfly Monitoring Initiative (RMI) is a national citizen science scheme set up in 2007 by the Riverfly Partnership as a way to help local anglers monitor the health of the river they fish. Since these beginnings, there are now over 2000 trained volunteers working at an estimated 1500 sites across the UK. 

This impressive volunteer base helps to collect much needed long term data on the water quality of our rivers.


What are Riverflies?

When we say riverflies, we are referring to key groups of invertebrates that rely on rivers for their life cycles:

  • Caddisflies
  • Up-winged flies
  • Stoneflies
  • Gammarus – freshwater shrimp

Caddisflies, stoneflies and up-winged flies spend the majority of their lives living on the bed of rivers as larvae, and then emerge on mass as short lived adult flies.

Underpinning the freshwater ecosystem, riverflies (and other freshwater invertebrates like freshwater shrimp) are a key link in the aquatic food chain, with many other species dependent upon them.

These tiny animals can be sensitive to poor water quality so their presence/absence or abundance can be used to indicate pollution problems in the river. 


Riverfly on the Hogsmill

Riverfly monitoring on the Hogsmill has been taking place since 2014, initiated by the Zoological Society of London (ZSL).

Each month, trained volunteers meet at the site and undertake a riverfly count. This involves taking a kick-sample which collects all of the invertebrates hiding on the river bed. Our volunteers then count these critters to give a score for the site, which is used to identify a potential pollution event and can be compared to previous surveys.

We’ve amassed a lot of information about water quality along the Hogsmill and our new Riverfly Monitoring Hub means we can now share the brilliant work of our volunteers with you!

This handy tool allows you to look back at data from previous years, at all the sites we monitor along the Hogsmill. It also gives you a snapshot of the latest results, hot off the press from our volunteer surveys.

Take a look at the hub yourself by clicking HERE!

Our Riverfly programme is currently funded as part of the Water Catchments for Communities project with Thames Water.