However, model flow results have been validated against measured streamflow data from several U.S.G.S. gauge stations. Total drainage areas of subbasins used in the validation effort compare well with drainage areas reported by the gauge station located at or near the subbasin's outlet. In general, simulated annual mean flows and standard deviations compare well with measured values. If a subbasin has upstream contributions then loads for this subbasin will include the accumulated loads from all upstream subbasins that make up the total drainage area. Total nitrogen is the sum of organic nitrogen in sediment, nitrogen in surface runoff, and nitrogen in subsurface flow.
Total phosphorus is the sum of soluble phosphorus and phosphorus attached to sediment.
The TSS was taken as SWAT sediment yield. The SWAT model generates many types of nonpoint source files . Only the most important files are provided as deliverable files. SWAT model results from the SBS file were compared with literature values. There is some uncertainty in the use of literature values, since it most probably includes detects.