DESIGN CREATED WETLANDS WITH WETBUD – A WATER BUDGET MODELING TOOL

Wetbud, a new free tool for estimating wetland water budgets, uses available weather data and site-specific geohydrologic, topographic, and soil data, driven with mass-balance mathematics. Developed by an interdisciplinary team and validated at multiple sites in Virginia using established and new water budget procedures, Wetbud was primarily intended as a planning tool for use in the design of created wetlands. It can also be applied to native wetlands or wetland restoration sites with sufficient data. Wetbud can be run in its Basic form where wetland topography, and soil parameters, surface overland flow and groundwater flux from adjacent hillsides are simplified; in the Advanced form these parameters are included in a more complex approach that uses a finite difference model (MODFLOW) and thus can include slopes or more irregular topography in the model. Both versions can also include estimates of overbank flow from adjacent streams. The program locates weather records from nearby stations, downloads data sets selected by the user, and following a modest user data clean-up step, determines appropriate wet-normal-dry (W-N-D) years for that station. Also, for many humid-temperate climate settings (e.g. Virginia to Missouri), Wetbud can use Effective Monthly Recharge (W_em) calculations based on existing short-term (e.g. 9-to-12 months) groundwater data from an up-gradient well to simulate longer-term groundwater inputs for historic periods with no well data, such as the selected W-N-D years. In addition, Wetbud features a “Wizard” version that contains 14 pre-selected weather data sets that cover Virginia which let the user develop a simple monthly water budget in less than 15 minutes – a feature that could be expanded anywhere geographically with historic weather data. Wetbud runs in Windows environments and is now freeware available for public use from www.landrehab.org/WETBUD.