UTILIZATION OF HISTORIC WET-WEATHER MONITORING DATA TO CALIBRATE AN URBAN APPLICATION OF HYDROLOGIC SIMULATION PROGRAM – FORTRAN

An urban application of the Hydrologic Simulation Program – FORTRAN (HSPF) was developed to simulate delivery of nine (9) land-based water quality constituents to the Lynnhaven River which drains to the Chesapeake Bay. In order to capture the range of imperviousness and land management practices within the watershed, each parcel was assigned one (1) of nineteen (19) urban land use categories. Existing HSPF documentation, including case studies and calibration aids, focuses on much less urbanized watersheds where a single urban land use is common.In order to develop and calibrate the model parameters required to simulate the fate and transport of the water quality constituents in a timely and cost-efficient manner, the City of Virginia Beach proposed using data from three (3) wet-weather monitoring sites in and around the Lynnhaven River Watershed previously collected as a part of their Virginia Pollutant Discharge Elimination System (VPDES) permit.A simple HSPF model of each monitoring site was created and land use categories were assigned at the parcel level to correspond with those in the Lynnhaven River Watershed HSPF model. Model input parameters were then calibrated for each constituent and land use category by using summer and winter event mean concentration and unit area load values developed from the aforementioned monitoring effort.