Seddeer: a Sediment Transport Model for Water Quality Modeling

In this study, a stand-alone sediment and contaminant model, SEDDEER (Sediment Deposition and Erosion), is presented. The model simulates one water box and underlying (multiple) sediment bed layers, and was developed for incorporation into water quality models. The processes incorporated in the model are: settling and deposition, resuspension, equilibrium adsorption/desorption, sediment-water interface diffusion, volatilization and decay, sediment bed, and consolidation. In contrast to other models, SEDDEER simulates multiple sediment classes, includes a flocculation model, and considers both cohesive and noncohesive sediments. Comparisons of SEDDEER-simulated results with analytical solutions, experimental data from other studies, and simulation results from another model, EFDC (Environmental Fluid Dynamic Code), were performed. The SEDDEER algorithm for flocculation settling was successfully verified for mass conservation of both sediment and contaminant. The test for estimating settling/deposition revealed that for shear stresses of 0.00 and 0.05 Pa, the coefficient of determination (R) ranged from 0.98 to 1.00. SEDDEER’s contaminant transport algorithm was tested against reported measured data of dichlorodiphenyldichloroethylene (DDE). SEDDEER-calculated output for the water column and sediment bed fit the measured data with R = 0.94 and R = 0.74, respectively. Lindane (γhexachlorocyclohexane) field data and SEDDEER output for contaminant transport also agreed well (R = 0.85).