The Chilterns Chalk Streams Project co-ordinates Riverfly citizen science monitoring for the Colne & South Chilterns hub.


Colne & South Chilterns Riverfly Hub Map

We work collaboratively with Herts and Middlesex Wildlife Trust who also co-ordinate Riverfly monitoring as part of the Lea Catchment Partnership to the east of the Chilterns.

Chilterns ANOB

What is Riverfly?

Riverfly is a national citizen science method that was laucnhed by the Riverfly Partnership in 2007, aiming to monitor the presence and abundance of target groups of freshwater riverflies to determine river health.

This is an Environment Agency-approved citizen science method, therefore after a site has been monitored for 6-12 months, the EA will set a trigger breach score that will differ for every monitoring site. Should your monthly score drop below the trigger breach, the EA should come out to investigate any potential pollution events as a result of Riverfly monitoring.

To become a Riverfly monitor, you will need to take part in a one-day training session to receive your certification and monitoring equipment, these are generally held twice a year in the Chilterns hub, once in spring and another in autumn.

Each river has a co-ordinator that is the primary point of contact for monitoring. They can organise for potential new monitors to shadow an existing Riverfly monitoring pair, or may be able to organise a public taster session if there is enough demand.

Chilterns ANOB

First annual newsletter – 2024


We have launched our very first Chilterns & Middlesex Hub annual Riverfly newsletter!

Read an update from each of our river groups in both hub catchments, learn about non-native species, understand how we’re working with students to analyse our data, find out how you can get involved if you’re brand new to Riverfly, and much more!

View our data

As Riverfly is a national citizen science method, the data is publicly accessible online for anyone to view and download.

The national Riverfly Partnership have very recently migrated all their data onto the Cartographer system (free registration for an account). We also hold some of our Riverfly data on a local Rflies website.

RFlies Riverfly data for Chess

Upcoming Riverfly training & events

Chilterns ANOB

Riverfly training day

  • 3 August 2024
  • 9:30

The Chilterns Chalk Stream Project are hosting this Riverfly monitoring training day...

Chilterns ANOB

Riverfly Open Day 2024

  • Saturday 5th October
  • 12pm

The Chilterns Chalk Stream Project and Herts & Middlesex Wildlife Trust...