Date of this Version
Published in Irrigation Science (2020) 38:481–483
Groundwater stored in aquifers is a major source of irrigation water for many agricultural regions that receive insufficient precipitation for crop production. In the U.S.A., the High Plains aquifer (HPA) that underlies parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming supplies irrigation water for agricultural production. The HPA underlies around 450,658 km2 (174,000 mi2) of which the Ogallala aquifer is the principal geologic formation underlying 347,059 km2 (134,000 mi2) (Gutentag et al. 1984). The Ogallala aquifer is primarily a water table (unconfined) aquifer with saturated thickness ranging from 0 m to about 366 m (McGuire 2017). Average annual precipitation ranges from 400 mm in the west to 800 mm in the east of the Ogallala aquifer region (OAR), while mean annual pan evaporation ranges from 1500 mm in the north to 2700 mm in the south of the OAR (Zhang et al. 2019).
The papers in this special issue report results of collaborative research primarily supported by the United States Department of Agriculture (USDA)-National Institute of Food and Agriculture Ogallala Water Coordinated Agriculture Project (CAP) that bring together researchers from more than ten institutions across six States in the OAR (https://ogallalawater.org/). The nine papers cover a broad range of irrigation management topics under two main categories as follows.