WETBUD CALCULATES WETLAND WATER BUDGETS EFFICIENTLY USING REGIONAL WEATHER DATA FOR VIRGINIA SITES

Wetbud is a free software package that streamlines the production of design-scale water budgets for small prospective wetland sites. It uses site characteristics supplied by the user along with NOAA weather data, which it retrieves, to generate monthly water budgets needed by mitigation wetland designers and regulators. Applicable in a multitude of hydrogeomorphic settings, Wetbud calculates budgets for typical Wet, Normal, and Dry years, as well as custom time periods, by estimating multiple sources and losses of water for the site. In addition to (1) precipitation falling onto the wetland, it calculates (2) groundwater influx by using the Effective Monthly Recharge Model and Darcy’s Law, (3) sideslope runoff using Curve Number assessments, and (4) overbank flow into the wetland using Unit Hydrograph simulations with different weir shapes. Wetbud estimates losses from the proposed wetland via (1) evapotranspiration using either Thornthwaite or Penman-Monteith calculations, (2) groundwater seepage out using Darcy’s Law, and (3) surface water outflow via inverts. In its simplest (Basic) version Wetbud produces analytical solutions to produce monthly hydrographs; the Advanced version of Wetbud serves as a graphical user interface for the USGS MODFLOW numerical groundwater flow model with stress periods developed directly from the NOAA weather stations saved in its database. Wetbud has been tested at nine sites in the Coastal Plain and Piedmont physiographic provinces of Virginia including an upland vernal pool, sloping wetlands, lacustrine and tidal fringe wetlands, and toeslopes and floodplain wetlands. Currently, Wetbud is distributed with fourteen preloaded weather stations, all located in Virginia, though users may develop their own weather data sets and water budgets for anywhere in the United States. Future work will develop additional regional weather data sets for adjacent states.