The River Rangers

The Rivers Team runs projects across the Colne Valley Regional Park area and into the wider Colne Catchment area. These projects are all part of our wider goals to protect, conserve and advocate for rivers throughout the Colne catchment for wildlife and people.

Pollution Monitoring
The pollution monitoring project aims to contribute to our ongoing work on monitoring and improving water quality. This project involves the production a map of all outfalls and pollution reports across the catchment, utilising multiple data sources and ongoing surveying. Volunteer pollution monitors survey local rivers near them to monitor for any pollution, and survey for this using our surveying form. By producing a map and encouraging pollution surveying, this will allow future efforts to improve water quality by solving issues at identified sites and directing efforts towards the worst affected areas.

Riverfly Monitoring
Riverfly monitoring is a national initiative set up by the Riverfly Partnership that involves surveying our rivers for small invertebrates and crustaceans that are key indicators of water quality. Riverfly monitoring occurs on every river throughout the Colne Catchment. By surveying riverflies on a monthly basis, we can establish data on the health of our rivers and report water quality incidents to the Environmental Agency. Volunteers are trained by the Riverfly Partnership to learn the surveying method and riverfly identification, before being assigned or set up at a site on a river near to them as part of a team of volunteers which will monitor this site. The aim of Riverfly monitoring is to collect long-term data on riverflies and water quality, so volunteers must be able to dedicate to long term volunteering at least once a month.

Floating Pennywort Removal
Floating Pennywort is a highly invasive plant species originally from South America that is prevalent across the Colne Catchment. The Rivers Team and the River Rangers aid in the management of floating Pennywort by supporting manual removal efforts. The aim of this project is to manage floating pennywort rafts across the catchment, minimise spread, and eventually eradicate it from the area. By doing this we can minimise the ecological and economic impacts of floating pennywort in the short term, and in the long term remove this stressor from the environment across the catchment. To find out more about the impacts of floating pennywort, check out our invasive species information page.

We work across areas throughout the Colne Catchment where floating pennywort is present to remove this invasive plant using any means possible. We are active on the Canal, the river Bulbourne, the river Colne and some of its tributaries where infestations of floating pennywort are present. To conduct these removal efforts we work with contractors, local canoe clubs, Canal and Rivers Trust, Boxmoor Wildlife Trust, Hillingdon Council, local angling clubs and the River Rangers. Volunteers often get involved from the banks and in the water, either manually hand picking pennywort out of the river or pulling rafts out using throwing anchors and rakes.

Currently, this project is focused on removal efforts in Denham Country Park along the stretch of the River Colne running alongside The Buckinghamshire Golf Club. This work will be conducted using contractors, due to the depth of the river and the extent of the infestation. However, future work is likely to span all the way up to Rickmansworth to completely clear this area of the Colne.

Biocontrol for Floating Pennywort and Himalayan Balsam
We are working with CABI on an exciting initiative trialling forms of biological control to manage the populations of invasive plants of Floating Pennywort and Himalayan Balsam in the Colne Catchment. Biological control refers to the introduction of herbivores or disease that specifically target the invasive plants that are causing problems. These forms of biological control have been carefully trialled and tested by CABI to ensure they are safe for release into the environment. They have the potential to save lots of money by reducing the need for physical removal efforts, so check out CABIs website for updates and to find out more about these initiatives.

Invasive species monitoring
To guide and inform our invasive species management across the Colne Valley, we also carry out invasive species monitoring. The goal of monitoring is to improve our ability to monitor current invasive species populations, identify new areas which have been invaded, and evaluate effectiveness of removal works. Additionally, by monitoring for invasive species we are able to better direct removal actions to areas which need them most. We are constantly looking to expand the areas we can monitor for invasive species, so please get in touch via [email protected] to volunteer to monitor an area near you.