Case Study- River Mole, Leatherhead

Case Study Beverley Brook Aquamaintain LTD

Case Study

Background Scope of the Project The River Mole at Leatherhead between Thorncroft Bridge and Common The area is an important, accessible open space, valued for both Meadows is one of the most publically- wildlife and recreation: walking, fishing and bird watching. accessible stretches of the River, with a Being a public space, it was of utmost importance to minimise mixture of open spaces, industrial and disturbance to the surrounding area and its users. economic uses. The aim of the project was to improve aquatic habitat diversity The river here is slow flowing in places, for wildlife, fish and invertebrates, improve the flow variations overwide and has deeply incised banks. within the watercourse and create access points to the water’s These areas provide little habitat variation edge where heavy soil erosion had already occurred. for invertebrates and fish. Working in partnership with Surrey Wildlife Trust, the River Due to the nature of the pubic space some Mole Catchment Partnership and the Environment Agency a areas of bank had become heavily eroded number of problem areas were identified. due to dog walkers trying to access the water. The works Involved the creation of two public access points/dog dips to the water’s edge, the installation of a planted wetland berm, the installation of two log deflectors, a brushwood berm and the erection of 150mm of post and rail fencing and gates.

As part of the Horley to Hersham Waterbody … it currently has an overall ‘moderate’ ecological status according to its Water Framework Directive classification.

Case Study River Mole, Leatherhead

Solution To prevent further bank A tracked excavator was used to Approximately 150m of post and re-profile the bank behind the erosion at popular access rail fencing was erected parallel newly installed berm and locally points to the water’s edge, two to the river, aiding the sets of timber steps were sourced native aquatic plants were installed to encourage access planted to kick start establishment. establishment of an un-grazed buffer zone that will create for dogs and members of the Further in-channel habitat was public. created in the form of a brush habitat and help stabilize the eroding banks. The fence was A vegetated wetland berm wood berm approximately 10m in constructed from Hazel length, on the inside of the bend on post-and-rail type, to keep Faggots was installed adjacent the right bank, upstream of livestock out but allow the free to the right hand bank on Thorncroft Bridge. flow of floodwaters. A five bar Bluebird island, where the Two downstream pointing flow gate was also included for access river was slow flowing and deflectors were also installed on the to the buffer zone for the local deep to narrow the over wide right bank to reduce the erosional angling club and essential river channel and introduce pressures on the sheet piles on the bankside maintenance. habitat. left hand bank.

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Aquamaintain LTD Frensham Vale Stables, Gardeners Hill Rd, Frensham, Surrey, GU10 3JB

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