Netherton Burn Restoration, River Doon

Purpose of Grant

A habitat restoration project in a degraded but important Ayrshire spawning burn.

Project Description

Ayrshire Rivers Trust (ART) in collaboration with Netherton Farm, SEPA and the River Doon District Salmon Fishery Board (RDDSFB) plan to work in collaboration to transform the Netherton burn. The lower reaches of this burn supports low densities of juvenile salmon and trout however due to historic pollution incidents (which have now been resolved), the presence of a defunct weir and ongoing silt inputs from a large eroding terrace, the quality, condition and accessibility of this burn are poor but the underlying potential of the watercourse is very high.

This project will improve the quality of the instream habitat, open up access for migratory fish species, establish protected water margins and reconnect the Netherton Burn to part of its floodplain.

The River Doon and its tributaries, including the Netherton burn, supports nationally important fish species such as Atlantic salmon, brown trout (including sea trout), lamprey and European eels. Access for migratory salmonids is currently restricted due to an old bridge culvert and a defunct weir. Both structures act as obstacles and prevent access to nearly 1km of potentially very good spawning and juvenile habitat.

Through this project oak baffles will be installed into the culvert, increasing the water depth (the limiting factor) and allowing fish passage. Under license from SEPA and with permission of the owner, the small weir will be removed to allow unobstructed access for migratory fish species. In conjunction with opening up access, livestock fencing will be installed to create protected water margins, preventing further livestock poaching and destabilisation of the riverbanks. 500 native trees (of various sizes and species) will be planted within these new water margins to create diverse riparian habitats that will eventually contribute leaf litter and woody debris as well as provide shade, keeping water temperatures down.

On the right bank of the Netherton burn, there is a large eroding terrace (approximately 50m by 14m) that contributes a large amount of silt and soil directly in the burn each year, smothering what should be good spawning habitats. Green engineering techniques will be used such as brash bundles, willow mattresses, willow stakes and coir matting to stabilise this eroding terrace and reduce the soil input. Native willow will be planted to develop a root matrix that binds loose, alluvial soils together and act as a buffer against further landslips. The upper area of the eroding terrace will be regraded before covered with coir matting and seeded with native grasses and wildflowers to encourage native vegetation and stabilisation.

To ensure the long-term viability of the work and to allow the green engineering to establish and root, flood channels in the form of small ditches and dry channels will be dug out within the floodplain to alleviate pressure away from this riverbank during floods. Furthermore by

allowing the Netherton burn to access its floodplain, salmonid redds will be protected from wash out and water will be retained for longer before being released back into the burn.

Budget

The project has been awarded a grant of £15,543 from the fund.