Salix designed and constructed a stream enhancement project at a gas pipeline river crossing as ecological mitigation to a degraded reach of stream as part of a major pipeline project.
Salix were asked by Main Contractor Murphy Pipelines to assess a degraded reach of the River Pinn near Ickenham with the goal of enhancing the reach.
The channel had been modified previously and was characterised by slow water flow, over deep and ponded with a silty bed and steep banks covered in nettles.
Salix designed and constructed a 40 metre enhanced channel and imported flint reject stone was used to create in-channel features, two riffles and a point bar. The gravel has concentrated the low flows and revived water flow in the reach.
Locally harvested tree trunks were used to create a double flow deflector. Additionally, a large backwater was created on line and just downstream of the enhanced reach.