Texas Faces Aquifer Water Depletion In The Face Of Growing DemandFebruary 13, 2012
National Geographic has recently completed a journalistic segment about a group of farmers in northwest Texas which began 2012 under circumstances past generations could only imagine. According to a new rule implanted by the High Plains Underground Water Conservation District based out of Lubbock, Texas, the farmers will now face a limit on the amount of groundwater they can pump from their own wells on their own property. Pursuant to the new rule, water pumped in excess of the "allowable production rate" is illegal.
National Geographic points out that most of Texas abides by the legal concept of "rule of capture," which can broadly be interpreted as a doctrine of "first to come, first to serve." However, farmers in the Texas Panhandle rely on the Ogallala aquifer to irrigate their crops. Many environmentalists have already expressed concern about the depletion of the aquifer. Authorities feel that if the region is to have any future, there must be some restriction on freshwater pumped from the aquifer.
National Geographic explains that when farmers first settled the High Plains region they relied on windmills to help them lift groundwater from the aquifers. However, in the 40's and 50's irrigation levels soared in correlation with powerful motor pumps and large sprinkler systems. These technological advancements caused irrigation to increase five fold in the region during the latter half of the 20th century. Many authorities feel that intense irrigation of the aquifer over time has led to its gradual depletion.
National Geographic points to a study done by the U.S. Geological survey since 1940 which shows the total volume of water in storage in the High Plains aquifer has declined by some 266 million acres-feet. This volume is equivalent to 2/3 of the water in Lake Erie, one acre foot equals 325,850 gallons. This study can be viewed at the following link: https://pubs.usgs.gov/sir/2011/5183/. Further, National Geographic reported that the drainage of the High Plains aquifer is increasing in speed. Reportedly, the average annual depletion rate between 2000 and 2007 was more than twice that during the previous fifty years. The aquifers depletion is most apparent in its southern portion, specifically Texas. National Geographic reports that the water table beneath certain areas of Texas has dropped up to 150 feet.
Further, the news magazine reports that water in the Ogallala is not expected to replenish anytime soon. Scientists believe that the Ogallala filled slowly during the ice tens of thousands of years ago. This has prompted criticism of water allocation by people like USGS director Marcia McNutt, who has criticized water practices for depleting in a hundred years what it took nature more than 10,000 years to create.
National Geographic states that that new irrigation rule in west Texas is just one step in the process of adapting to the very real threat of running out water in the state. The water district in Lubbock Texas has set a water management goal of retaining at least 50% of Ogallala's ground water in the next fifty years. National Geographic points out that this will not be an easy goal to meet as the USGS study found that 29 percent of Texas's portion of the Ogallala aquifer has already been depleted. However, Texas farmers have already started adapting to reducing the amount of water which is irrigated. The High Plains Water District maintains that irrigation efficiency rose from 50 percent in the mid-seventies to 75 percent by 1990. Since then, more farmers have adopted low-pressure drop-line sprinklers that deliver water closer to the crops instead of spraying it high in the air. When combined with field methods that conserve water in the soil, these precision sprinklers can achieve efficiencies of 95 percent. Some cotton farmers that have installed sub-surface drip systems, which deliver water at low volumes directly to the crops' roots, have achieved efficiencies approaching 100 percent