Sediment is also routed through ponds and reservoirs. LAI is computed for each day from the maximum LAI and total above ground biomass. The ET component uses LAI to compute plant evaporation. Water and temperature stress factors are used as growth constraints. Annual crops grow from planting date to harvest date or until the accumulated heat units equal the potential heat units for the crop.
Perennial crops maintain their root systems throughout the year.
Lake water quality simulation can be applied when a single reservoir is simulated at the basin outlet. The major processes in the toxic balance are loading, outflow, reactions, volatilization, settling, diffusion, resuspension, and burial, while in the phosphorus balance, the balances are loading, outflow, and settling. The model tracks the fate of pesticides from their initial applications on the land to their final fate in the lake. This allows decision makers to directly predict the influence of upland agricultural management decisions on lake water quality.