Submitted to: Journal of Irrigation and Drainage
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/30/2007
Publication Date: 7/1/2009
Citation: Colaizzi, P.D., Gowda, P., Marek, T.H., Porter, D.O. 2009. Irrigation in the Texas High Plains: A brief history and potential reductions in demand. Journal of Irrigation and Drainage. 58(3):257-274. Interpretive Summary: Irrigation is vital to the economy of the Texas High Plains, with fifty percent of the cultivated land under irrigation providing over eighty percent of crop production and gross revenue. However, irrigation in this region is dependent on the Ogallala Aquifer, which is declining because groundwater withdrawals exceed recharge, and this threatens its long-term sustainability. Groundwater withdrawals could be reduced without reductions in irrigated land area or crop productivity by 1) increasing adoption of weather-based irrigation scheduling (i.e., using the Texas High Plains Evapotranspiration Network); 2) converting the remaining gravity-irrigated land to center pivot irrigation; and 3) replacing corn with cotton, which has similar revenue potential for half the water requirement in the Northern High Plains counties.
Technical Abstract: Irrigation for crop production in the semi-arid Texas High Plains is dependent on groundwater withdrawals from the Ogallala Aquifer, which is declining because withdrawals exceed natural recharge. Irrigation development in the region accelerated during the 1950s. Both irrigated area and volume pumped peaked in 1974 and steadily declined during 1974-1989. By 2004, however, irrigated area was nearly the same as it was in 1958, and volume pumped had increased slightly. The expanding beef, dairy, and swine industries in the region, along with new demands for grain feedstocks for biofuel production, have resulted in record commodity prices. This will provide strong short-term incentives for accelerated pumping from the Ogallala; however, groundwater management authorities in Texas are now required to establish upper limits on groundwater production. Several strategies to reduce groundwater withdrawals were reviewed without any reductions in irrigated land area or crop productivity. The most promising evaluated were: 1) Increasing weather-based irrigation scheduling using the Texas High Plains Evapotranspiration Network (TXHPET); 2) Converting gravity-irrigated land (27% of total) to center pivot irrigation; and 3) Replacing high water to lower water demand crops (i.e., corn to cotton). If the land area using the TXHPET network was doubled, and if gravity-irrigated lands were reduced to 10%, groundwater withdrawals could be reduced by 14%. An additional reduction of 8% may be possible by converting half of the irrigated corn area to cotton.