Dynamic agricultural non-point source assessment tool (DANSAT): Model development

Non-point source simulation models are commonly used tools for examining water and water quality issues. The dynamic agricultural non-point source assessment tool (DANSAT) is the distributed-parameter, physically-based, and continuous-simulation model for simulating the spatial and temporal impacts of agricultural best management practices (BMPs) on hydrology and water quality in small agricultural watersheds. The development of model components is described in this paper with results on temporal and spatial evaluation, sensitivity analysis, and application of the model presented in the companion paper. Three model components including dynamic variable, hydrology, and sediment components are described. The dynamic variable component includes interactive soil, plant growth, and residue decomposition subcomponents which predicts temporal changes in hydrology- and detachment-related soil parameters, crop variables, and the decomposition of three types of residues, respectively, according to applied land management practices. The hydrology components include interception, evapotranspiration, infiltration, percolation, overland flow, channel flow, interflow, and base flow components. Sediment components simulate interrill detachment, rill detachment, channel detachment, transport capacity, overland routing, and channel routing.