This supplemental material section contains detailed information on the input data assumptions for the SWAT modeling as well as the model calibration and validation results. The data sources listed in Supplemental Table 1 were used to build the SWAT TMDL modeling system for the Raccoon River watershed, most of which are accessible in the Iowa Department of Natural Resources (IDNR) on-line digit...

Strategies are sought to reduce the impact of nonpoint sources of pollution, including fecal bacteria, and meet TMDL criteria. Vegetative filter strips (VFSs) are one such strategy. VFSs were found to be effective in removing abroad range of constituents from beef feedlot runoff pretreated by a settling basin. The first 30 m provided most or all of the reductions found within the 150-m VFSs stu...

Non-point sources of pollutants originate at the field scale but water quality problems usually occur at the watershed or basin scale. This paper describes a series of models developed for poorly drained watersheds. The models use DRAINMOD to predict hydrology at the field scale and a range of methods to predict channel hydraulics and nitrogen transport. In-stream changes of N load are estimate...

Water quality impairment due to high mercury fish tissue concentrations and high mercury aqueous concentrations is a widespread problem in several sub-watersheds that are major sources of mercury to the San Francisco Bay. Several mercury Total Maximum Daily Load regulations are currently being developed to address this problem. Decisions about control strategies are being made despite very larg...