GIS - A TOOL FOR SITING FARM PONDS

A geographic information system (GIS) application was developed for id entifying potential sites for a farm pond to serve as a permanent live stock watering system amenable to rotational grazing and independent o f ephemeral streams. The approach consisted of the following component s: (1) developing the digitized database and attribute files, (2) loca ting potential sites based on topography, land use, and soil, (3) cond ucting a water balance for each potential site, (4) ranking the potent ial sites as to desirability and (5) recommending ways to enhance wate r harvesting capabilities. The GIS screening produced maps showing the locations of suitable pond sites. Based on these maps, the watershed of each site was determined and the potential runoff to the pond was p redicted using the Natural Resources Conservation Service Curve Number Method. Spreadsheet calculations were used for performing a water bal ance. Potential pond sites were selected for further consideration bar ed on a slope of 8% or less, soil suitable for aquifer-fed ponds, and land areas not used for homesteads, croplands, utilities, roads, or st reams. Using water balance calculations for 10 years of simulated clim ate data, the potential amount of water harvested at each site was det ermined. Using water harvesting potential, location, and negative impa cts of a pond at a specific site as criteria, nine sites were ranked a s most desirable.