Contribution-Based Watershed Assessments
Using local watershed data and conditions to derive improvement fees.
Watershed districts have the authority to fund projects based on benefits or contributions to water quality issues through the development of water management units. The Sauk River Watershed District is developing the framework to fund best management practices (BMPs) within ten management units established in its watershed management plan. Runoff coefficients were developed with an HSPF model application that considered land use, soils, and slope. The coefficients were applied to parcels to determine the relative contribution of each parcel to surface-water runoff and phosphorus loads within a management unit. Costs for a volume or phosphorus reduction practice can be distributed based on this relative contribution. A coefficient generator and fee calculation tool allows the user to define project cost, assessment area, base fee, years of assessment, and interest rate. Changes to parcel boundaries or land cover can be incorporated into the approach without rerunning the HSPF model.