On-farm irrigation reservoirs in two Arkansas critical groundwater regions: A comparative inventory

Abstract

Arkansas, which ranks third in the nation in terms of irrigated cropland, relies heavily on the Mississippi River Valley alluvial aquifer for irrigation. Two critical groundwater areas have been identified, with one in the Grand Prairie in central Arkansas and the other along the Cache River in northeast Arkansas. Thus, there has been a call to develop surface water resources for irrigation, and as a result, on-farm irrigation reservoirs have been constructed to capture and store surface water. To assess the current state of surface water development, a remote-sensing survey using National Agricultural Imagery Program data was conducted to provide an inventory of the locations and surface area of on-farm reservoirs in the two critical groundwater areas. Expert consultation and on-site inspections were used to confirm the remote sensing results. In the larger Grand Prairie area, where aquifer decline was recognized earlier, 632 reservoirs were identified for a total surface area of 9,300 ha. In the Cache River area, 143 reservoirs were identified for a total surface area of 2,000 ha. Average reservoir size in both regions was 14.6 ± 20 ha and ranged from 1 to 265 ha. Reservoir area comprised approximately 3% and 1% of the areas of potentially-irrigated cropland in Grand Prairie and Cache River regions, respectively.