Catchment Management

The Chelmer and Blackwater Catchments

Rivers Chelmer and Blackwater

The Rivers Chelmer and Blackwater both rise in and flow through the county of Essex. The River Chelmer rises near Thaxted and flows mainly southeast towards Chelmsford, where it is joined by the River Can. It meets the River Blackwater at Langford near Maldon where it flows to the North Sea.

The River Blackwater rises in northwest Essex as the River Pant. It flows through Braintree and is joined by the River Brain before flowing towards Maldon and out to the North Sea via the Heybridge Basin or the tidal Chelmer.

The Chelmer & Blackwater catchment is 988 Km2 and is intensively farmed for predominantly arable crops, with a small amount of livestock. The landscape is gently rolling with a soil type of mainly loams and clays.

River water quality

Nitrate, and the pesticides clopyralid and metaldehyde can be present in the river water and are extremely difficult to remove through the treatment process. These substances mostly originate from agricultural land where they are applied as fertiliser, and to prevent weed growth and damage to crops by slugs. Phosphate and sediment also coming from the land can result in poorer river water quality. Removing these substances from the river water requires additional amounts of chemicals and energy, and therefore increases the cost of producing drinking water.


Essex & Suffolk Water is a member of the
Chelmer & Blackwater Strategic Partnership, along with the Environment Agency and Natural England’s Catchment Sensitive Farming (CSF) project. The Partnership works closely with Campaign for the Farmed Environment (CFE), National Farmers Union (NFU), Association of Rivers Trusts, farmers, land managers and agronomists, among others, with the aim of reducing the amount of pesticides, nitrates, and also phosphate and sediments, running off the land into the rivers.

Events, training and advice

The Partnership hosts events, training and advice days on a range of topics and can provide free on-farm one-to-one fertiliser sprayer and pellet spreader calibrations, farm health checks, farm mapping and agri-environment visits. More information on the partnership’s work, including the regular newsletters and details on future events and free training opportunities for farmers, land owners and managers can be found on the partnership website

Your catchment advisor

Thomas Harris is Essex & Suffolk Water’s Catchment Advisor for the Chelmer and Blackwater. Having worked on farms in Essex and beyond from the age of 14, he has a good practical grounding of both the positive and negative aspects of farming in the catchment. In addition Tom has spent a total of 6 years studying Agriculture at Writtle University and has gained around 4 years working in crop trials for a large distribution company.

Catchment management

Catchment management  

Essex & Suffolk Water′s catchment management work aims to prevent deterioration and then improve the quality of water in the rivers and lakes that we abstract from for drinking water supply. Find out more

We use cookies on our website. By continuing to browse our website, you are agreeing to use our cookies. Terms and Conditions