Mapping Changes in Reservoir Surface Area Using Landsat Thematic Mapper Images

Majority of Wyoming is characterized as semi-arid environment where availability of water impacts agricultural operations, animal husbandry, and recreational purposes. Ranchers and farmers depend on reservoirs to sustain agricultural operations, and if the water level were to get too low it could adversely impact activities throughout the state. Unfortunately numerous reservoirs in the state are not gauged i.e., no data exists on how much water flows in and out of them. The objective of this study was to evaluate the potential of remotely sensed data to reconstruct surface area of Sixty Seven Reservoir located in Sublette County, Wyoming. Landsat Thematic Mapper data acquired in August of every year from 1985 through 2011 were classified and digital maps of the reservoir's surface area were generated. Surface area of this reservoir fluctuated between 58 hectares (1992) and 116 hectares (2011). Landsat images can be used to reconstruct surface areas of reservoirs that are not gauged, and can be less expensive than the traditional field survey methods.