SEPA Pilot Catchment Project – Options Appraisal and Outline Design – River Nith (Castlemains, New Cumnock)

cbec have developed detailed restoration designs for a reach of the River Nith at Castlemains, New Cumnock.

This reach was prioritised for restoration in the first phase of SEPA’s pilot catchment project because of the potential benefits of restoration to its Water Framework Directive (WFD) status for morphology and to natural flood management (NFM). Options within each sub-section of the reach were identified and assessed based on geomorphic and ecological factors, as well as practical, socio-economic, environmental and legislative considerations. Various options representing a range of degrees of intervention were proposed for each section.

Following engagement with landowners, a final option was confirmed to be taken forward to detailed design. High resolution topographic survey of the study reach was conducted using highly precise RTK-GPS equipment and quantitative sediment sampling was also undertaken. Both survey results and sediment distribution analysis fed into hydraulic modelling of the restoration area. This assisted with the development of the agreed design concept into a detailed design suitable for construction.