Project number 4 on the Mimram catchment plan, 'Stream bed improvement at Singler's Marsh', has been completed! 

Sixty tonnes of silt has been removed from the river bed and replaced with sixty tonnes of gravel.

The project took four days in total, as the silt was removed, moved out of the floodplain, and two different sizes of gravels were deposited in the river.  This was then raked and re-profiled by hand. 

The gravel will provide areas for fish, such as brown trout, to spawn in, and will also create habitat for aquatic invertebrates such as mayflies and caddis flies.  It has also created attractive areas which demonstrate how the bed of a healthy chalk river should look.

The gravel will be monitored by volunteers to track how quickly it is colonised by invertebrates and aquatic plants.

This project was funded by Natural England via the Lea Catchment Nature Improvement Area, and Welwyn Hatfield Borough Council, and was managed by Herts & Middlesex Wildlife Trust.


Gravel goes into the river

Design by LTD Design Consultants and build by Garganey Consulting.