U.S. GEOLOGICAL SURVEY GROUNDWATER TOOLBOX: A NEW GRAPHICAL AND MAPPING INTERFACE FOR ANALYSIS OF HYDROLOGIC DATA TO SUPPORT BASIN-SCALE UNDERSTANDING OF GROUNDWATER/SURFACE-WATER EXCHANGE
GW Toolbox v1.0 includes six hydrograph-separation methods--the BFI (Standard and Modified), HYSEP (Fixed Interval, Sliding Interval, and Local Minimum), and PART methods; and one recession-curve displacement method--the RORA method to estimate groundwater recharge from streamflow data. The GW Toolbox is a customized interface built on the non-proprietary, open-source MapWindow geographic information system software. The program provides graphing, mapping, and analysis capabilities in a Microsoft Windows environment. In addition to the seven hydrograph-analysis techniques, the GW Toolbox facilitates retrieving time-series data (streamflow, groundwater levels, and precipitation) from the USGS National Water Information System, pre-processed GIS coverages, and meteorological data from the National Oceanic and Atmospheric Administration National Climatic Data Center. Data can be analyzed with several pre- and post-processing utilities. Using these tools, the GW Toolbox provides methods to estimate many of the components of the water budget for a hydrologic basin, including precipitation; streamflow; base flow; runoff; groundwater recharge; and total, groundwater, and near-surface evapotranspiration. Examples of GW Toolbox input and output and select applications of the hydrograph-analysis methods for basins across the United States demonstrate how the GW Toolbox can be used to efficiently apply a suite of hydrograph-analysis methods to better understand basin-scale groundwater/surface-water exchange.