Description
The River Derwent, Yorkshire has a recognised fine grained sediment problem, impacting water treatment costs. Sediment budgets are a useful tool to understand where sediment in a river catchment is sourced, helping to optimise management. Within the River Derwent, 2 of the 4 operational catchments have a high occurrence of the invasive non-native species Signal Crayfish; however it is currently unknown how much sediment they contribute to the overall catchment sediment budget. This project monitored the River Derwent monthly from February to November 2022, assessing water quality changes (including grain size) and modelled the catchment to understand sediment sources. Results showed that the catchment is extremely complex – flow was the main forcing factor impacting sediment loads, however, locally important aspects such as soil erosion and agricultural runoff and Signal Crayfish were significant. Areas of high risk have been identified for future management. Currently, it has not been possible to attribute a proportion of the sediment budget to Signal Crayfish (and other sources), however modelled soil erosion from the River Derwent contributes 12% of the wider Ouse Catchment Area, with similar volumes from the Upper Rye and Upper Derwent sub-catchments. Future work could focus on monitoring the catchment using pump samplers or turbidity / flow sensors to be able to adequately track the pulse of sediment from Signal Crayfish. Research gaps relate to: how far downstream the pulse from Signal Crayfish activity extends and quantifying the impacts of Signal Crayfish beyond the reach scale.| Period | 2024 |
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| Held at | British Society for Geomorphology, United Kingdom |
| Degree of Recognition | National |