MAPPING AGRICULTURAL LAND COVER FOR HYDROLOGIC MODELING IN THE PLATTE RIVER WATERSHED OF NEBRASKA

Throughout the western United States, natural resources managers are attempting to address the growing, and often competing, demands that municipal, agricultural and environmental interests have for water. The Platte River Cooperative Hydrology Study (COHYST) is a multi-agency effort that seeks to improve understanding of the ecology, geology, and hydrology of the Platte River watershed in central and western Nebraska. Information regarding the types, areal extent, and locations of crops (especially irrigated crops) is critical for estimating consumptive use of water. Digital land-cover and land-use datasets of the central and western Platte River valley have been prepared for four years: 1982, 1997, 2001, and 2005. Mapping was carried out using multidate Landsat satellite imagery in combination with ancillary geospatial data. The mapping was validated using field observations collected independently. Overall accuracy of the maps developed ranged from 74% to 82.7%. All land-cover maps and full documentation are available online at http://www.calmit.unl.edu/cohyst/