Deficit Irrigation as a Strategy to Cope with Declining Groundwater Supplies: Experiences from Kansas

Abstract

The High Plains aquifer shown in Fig. 3.1 underlies 453,248 km2 in parts of eight states (Nebraska, Texas, Kansas, Colorado, New Mexico, Oklahoma, Wyoming, and South Dakota) making it the biggest aquifer in North America (Fig. 3.1). The predominant formation in the High Plains aquifer is the Ogallala Formation of the Miocene/Pliocene age (Sophocleous 2012), thus this aquifer is commonly referred to as the Ogallala aquifer. This predominantly unconfined aquifer comprises of silt, sand, gravel and clay, and varies in saturated thickness and permeability (Buchanan et al. 2009). For example, the predevelopment aquifer thickness and depth to water in Kansas varies from 15 m to over 90 m, and 8 m to over 105 respectively (High Plain Atlas). Most of the water from the aquifer is paleo or fossil water associated with the events of the last ice age when glaciers covered the Great Plains.