River Restoration: River Mimram

The client: Affinity Water

The site: River Mimram Restoration Project

The brief: To deliver a design and build river restoration project for the River Mimram, one of Hertfordshire’s valuable and rare chalk streams. The aim was to achieve a 70:30 ratio of direct sunlight to dappled shade whilst retaining important specimen trees and avoiding sensitive habitats.

Our solution: Our highly qualified ecologists and consultants carried out a range of surveys to identify key constraints and opportunities. The results indicated signs of otter, badger and water vole, there were several ivy clad trees which had bat roost potential. Method statements were complied for operatives to use when working near protected species and our licensed bat ecologist used a MEWP to carry out the bat roost assessment of trees.

The result: Utilising the method statements and restoration maps, our teams of tree surgeons and operatives undertook sensitive felling, coppicing, and pollarding of bankside trees alongside other enhancement works including the creation of an otter holt and construction of a viewing platform. Further to completion of the project, the river has responded well to the increased light levels, with surveys by the EA fisheries officer finding that it was much improved for spawning brown trout.

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