Author(s): Eric Gillies; Hamish Moir
Linked Author(s):
Keywords: Hydraulic models; Morphodynamic models; Salmonid habitat; River restoration
Abstract: Many Scottish river reaches have been historically straightened, either to align with transport infrastructure, like rail and roadways, or more commonly for agricultural reasons. This river straightening often leads to unform hydraulics, un-natural substrate dynamics and a loss of aquatic habitat diversity, along with issues of downstream flooding or channel perching. Substrate in a straightened reach of the River Nairn is shown in Fig. 1. River restoration seeks to re-introduce the natural process of alternating deposition, erosion and river sinuosity, which leads to a more diverse hydraulic and substrate habitat, in turn generating habitat suitable for salmonids such as trout and Atlantic salmon. To minimize risk in ‘setting the river free’, hydraulic modelling has been used for some time to model as-built flood risk and habitat. However, we present a relatively new approach, where we use hydraulic and morphodynamic modelling to present the future evolution, dynamic stability and growth of future habitat (supported by bathymetric, sediment surveys and fish counts/redd surveys) for river restoration.
Year: 2024