A New Framework for Modelling Fine Sediment Transport in Rivers Includes Flocculation to Inform Reservoir Management in Wildfire Impacted Watersheds

Fine-grained cohesive sediment is the primary vector for nutrient and contaminant redistribution through aquatic systems a critical indicator of land disturbance. A limitation most existing transport models that they assume characteristics fine can be described using same approaches are used coarse-grained non-cohesive sediment, thereby ignoring tendency to flocculate. Here, modelling framework simulate flow in Crowsnest River, Castle Oldman River Reservoir after 2003 Lost Creek wildfire Alberta, Canada was developed validated. It first include explicit description deposition/erosion processes as function bed shear stress flocculation process. This integrates four numerical models: MOBED, RIVFLOC, RMA2 RMA4 river geometry, flow, suspended bathymetry data. Sediment concentration particle size distributions computed by RIVFLOC were upstream boundary condition reservoir dispersion model RMA4. The predicted mass deposited within various sections indicate generated disturbance deposits reservoir. Deposition patterns from wildfire-impacted landscapes different than those unburned because differences settling behaviour. These may lead zones relatively increased internal loading phosphorus water columns, increasing potential algae proliferation. In light growing threats resources globally wildfire, generic herein propagation associated nutrients or contaminants reservoirs under conditions use scenarios. valuable tool support decision making management catchment planning.