Vermillion River Watershed Hydrologic Study of Existing Conditions

An innovative approach was used to build a hydrologic model of the 230-square mile Vermillion River Watershed, Minnesota. The model was used to set peak flow standards at locations where the Vermillion River or one of its tributaries crosses a community boundary. XP-SWMM was chosen because it is well-suited to detailed modeling of urban watersheds — making the model "expandable" for more detailed assessments of local communities. A combination of ground truth and NEXRAD precipitation data were used to account for the spatial and temporal variability of rainfall. In order to build confidence in modeling results and facilitate stakeholder buy-in, the model was calibrated using seven stream flow gauges located throughout the watershed. PEST, a parameter estimation software package, was used to automate calibration of hydrologic parameters.