River Can

Admirals Park is a large park towards the west of Chelmsford. Key features of the site include River Can which runs through the site towards its confluence with the River Chelmer, along with a number of historical relics including brickworks and old mills.

One of these historical features is an old mill channel, marked by a line of willow and alders. This old channel in the 150 years or so since the channel was active as become increasingly disconnected from te river. 

At one end it is now completely disconnected, whilst at the other downstream end, the channel has become perched. This means that any water found in the channel is of poor ecological quality. Normally, stagnant, heavily de-oxygenated and quite heavily polluted. This is because the main source of water is surface water runoff, rather than river water. This leads to a build up of grey de-oxygenated stagnant water which when flushed into the river during a time of heavy rainfall can cause fish deaths and other ecological issues. 

 Perched backchannel at Admirals Park

The plan, therefore, was to increase the connectivity of the old mill channel with the river to flush the stagnant water out to prevent the build up of this potentially polluting water. To do this we re-engineered the entrance by lowering and opening up the entrance to the back channel, removed and pollarded some willows and de-silted in places to increase capacity. 

Lowering and widening the entrance to the bay

The hope that, as the site settled down after the works, we will see the development of new and exciting ground flora, aquatic and emergent vegetation will develop and help to filter the pollutants out of the water. By re-engineering the entrance to the back channel it will also act as a fish refuge during times of high flow. A key issue on many of our rivers is the decline of fish populations. By providing places that they can spend times of high flow we can prevent fish, especially young fish from being displaced downstream and over time declining. Fish refuges work by providing a slower relatively calm area of water, that is still connected to the main river and allow fish to find refuge in. 

Lowered channel with water at all river depths

Post works the lowering and opening up of the channels is working well. There is a constant connection to the river at all times, allowing the development of flora. The backchannel is regularly flushed through during times of high flow and polluted water is filtered through the vegetation that is developing. 

The work was funded by the Environment agency with the support of Chelmsford City Council, who own the land at Admirals Park. 



River Can

WFD water body status


WFD overall status objective


Project lead

Essex Wildlife Trust

Contact for more information

This email address is being protected from spambots. You need JavaScript enabled to view it.

Project partners

Environment Agency

Funding source

Environment Agency

Project start


Project end


Website key stakeholders:

Environment Agency logo      Essex Wildlife Trust logo           ESWT Logo 70

Design by LTD Design Consultants and build by Garganey Consulting based on an original concept by Herts and Middlesex Wildlife Trust