Depleting the Ogallala Aquifer

The Ogallala Aquifer, also known as the High Plains Aquifer, is the primary source of water for many communities throughout the High Plains region. Stretching from South Dakota to Texas, the Ogallala Aquifer is one of the largest Aquifer systems in the U.S. It 's water is used primarily for agriculture, producing nearly one-fifth of the nation’s wheat, corn and cotton.

The southern High Plains has an (semi)-arid climate with rainfall amounts less than evaporation and far less than the water requirement of many agricultural crops. The Ogallala Aquifer in this region has a very low recharge rate. Water users in the southern High Plains have experienced significant declines in water levels, and consequently, increases in pumping costs.

During the 1950s and 1960s, agriculture in the High Plains began to expand both in irrigation systems and irrigated acres. The new irrigation systems provided a way to grow crops even during drought; however, larger and deeper wells were required to meet demands.

The most recent data (from 2013!) point to a drop in water level of about 4.5 metres when averaged over the entire Ogallala area[1]. However, the change in water level is highly variable in different areas of the Aquifer; no change or even water level rise was observed mainly in the northern area and significant declines measured in the southern High Plains.

Irrigation is the largest use of water in the Panhandle. There are approximately 930 square kilometres of irrigated land in Cimarron, Texas and Beaver counties, all requiring massive amounts of water.

The expansion of irrigated agriculture in Oklahoma Panhandle has been a major driving force for economic development and prosperity of this region. However, this growth has come at the cost of declining non-renewable water resources.

Since the predevelopment period (prior to 1950), about 3,000 irrigation wells have been drilled into the Ogallala Aquifer. Since then, water levels in the Ogallala Aquifer have declined more than 20 metres in Texas County and more than 15 metres in Cimarron County since predevelopment.

The period from 2010 to 2015 was characterized by a major drought in the region. During this five-year period, many new irrigation wells were drilled. The water level declines amounted to four metres in Texas County, almost three metres in Cimarron County and more than one metres in Beaver County over the same period.

The decline in the Ogallal water level has created numerous challenges for irrigated agriculture in the Oklahoma Panhandle. A main challenge is the reductions in pumping rates, resulting in higher energy costs and decreased revenue, as crop yields are decreased due to not meeting the full crop water requirement or planting a smaller area. In addition, as the Ogallala level decline and water is being extracted from deeper parts of the Aquifer the quality of water may degrade.

Since the Ogallala Aquifer has a very low recharge rate and other water resources are so scarce, efforts to increase the life of this valuable resource should focus on managing demand. Which, of course, will fail in the end, because you simply cannot sustainably produce loads of food in a (semi)-arid climate.

[1] Houston et al: Geodatabase Compilation of Hydrogeologic, Remote Sensing, and Water-Budget-Component Data for the High Plains Aquifer for US Geological Service Report - 2013.