The main impacts on water quality in the catchment arise from sediment and nutrients. These enter watercourses from many different sources such as: run-off from fields; roads; developed land; and septic tanks. Taken together, the collective impact of these sources of pollution is significant. It is exacerbated by pollutants from point sources such as sewage treatment works and industrial sites.

Sediment can be released into rivers as a result of some cultivation practices on arable land and allowing livestock to trample river banks. Sediment is also washed off roads into highway drains and into the river. It causes damage by clogging up river gravels, preventing fish from spawning and reducing the viability of their eggs.

Elevated phosphate levels can cause excessive plant growth leading to rivers being choked by weed and algae, reducing flows, removing oxygen from the water and reducing the capacity of the river to support animals, such as invertebrates and fish, which are the foundation of the catchment food chain.

To help achieve an improvement in water quality we must work with local industry, agriculture, and households to help them understand how to best store, use and dispose of chemicals to support the environment. We  will continue to work with the water companies to improve discharges from sewage treatment works and with domestic households and trades to understand the impacts of wrongly connecting the dirty water which comes direct from our washing machines, sinks and even toilets, straight into the river via the surface water drains (this is commonly known as a ‘misconnection’) 

Recently we have been working with the  Colne Valley Fisheries Consultative on an outfall monitoring initiative and they have provided an application and guidance on reporting & recording pollution incidents which can be found at 

Check out the website ( which  allows people to check how their local water company is performing and to compare with other companies. Led and funded by water companies, (with overview and scrutiny from regulators and consumer watchdog), it brings together information about how water and sewerage services are provided.

Design by LTD Design Consultants and build by Garganey Consulting. From an original concept by the Herts and Middlesex Wildlife Trust.