Ryevitalise Landscape Partnership - Engineering report; track work improvements with biodiversity

The purpose of this brief is to seek the services of a suitably experienced engineer and/or environmental consultant to produce an engineering report outlining proposed measures to reduce the negative impact a track is having on the freshwater environment of Bonfield Gill. Following a site visit with the land manager an engineering solution is sought to restore the track to a useable condition throughout the year while reducing or eliminating the impact runoff from the track is having on Bonfield Gill. Any solution must align with the aims of Ryevitalise and include biodiversity improvements in association with track improvements.

Birk Nab Farm (SE62189 90951) has land managed on both the east and west banks of Bonfield Gill. An access track runs east to west across the holding connecting Birk Nab Farm on the east to a track to Lund Farm on the west. The track is 1.16km in length and averages 3.0m in width, providing daily access throughout the year. The track is also the route of a footpath / public right of way (path number 532006).

The track descends a steep and direct route down the hillside before following a bend before the culvert crossing of Bonfield Gill. There have been repairs in the past to the surface using local crushed stone and creation of bunds to form cross-drains to divert runoff onto the fields. Stones used for repairs are sandstone so over time these crush and degrade, further adding to sediment loading intercepted in Bonfield Gill during periods of heavy rain. The track creates a direct pathway for runoff down the hillside, and has created a track that in places is deeply incised and in some places unusable. It is evident that maintenance to the cross drains is required as they no longer function and are detached from the track or full and vegetated.

Measures previously installed are now either defunct or need alterations in order to function effectively. The track is degrading and becoming deeply rutted and eroding, adding large quantities of sediment to the gill after each rainfall event.