Sub-Model Selection
The creation of unique cell groupings is also critical because it allows for the most appropriate field-scale sub-model to be used for each unique cell condition, more accurately simulating the daily runoff and groundwater in terms of both water quality and quantity. Based on the Soil and Land Use combination of the cell, the most appropriate field scale sub-model (see Technical Manual for sub-model details) will be selected to simulate that cell. The individual field scale sub-models used are specifically designed to deal with the particular natural processes that exist for those land use and soils combinations. The daily flows and loads produced by the Basin Unique Cell Shell (BUCSHELL) program produces a DAYFILE for each Unique Cell in the Basin. The DAYFILE contains the amount of nutrients and water that are leaving each cell on a daily basis.
Post Processing of Source Cell Discharge
The predicted daily time series of discharge simulated, by whichever sub-model is used, has to be further adjusted by the post process algorithm to account for the presence of impervious surfaces, storm water retention systems, street sweeping, human wastewater being discharged within the source cell, non-simulated BMPs (EMC override), and adjustment of nutrient speciation (see Technical Manual). The resulting surface and ground water flow and constituent loads leaving the source cell after these post process adjustments is then routed to the nearest stream as described in the next two sections.