The High Plains Aquifer, a critical water source for US farmers and ranchers, is diminishing at an accelerated rate and nearly 70 percent of it will be pumped out within the next 50 years if existing trends don’t change, according to a report published in the Proceedings of the National Academy of Sciences.
About 30 percent of the groundwater has already been pumped from the aquifer, including a portion of the Ogallala aquifer, which covers about 174,000 miles under parts of South Dakota, Nebraska, Wyoming, Colorado, Kansas, Oklahoma, New Mexico and Texas. Recharge rates are being outpaced by pumping and researchers forecast another 39 percent will be depleted if the agricultural industry doesn’t reduce its use.
The High Plains Aquifer supplies 30 percent of the nation’s irrigated groundwater and the Kansas portion — an area the study focused on — supports the congressional district with the highest market value for agriculture in the nation.
Eventually, the southwest and northwest districts in Kansas will experience shallower groundwater stores, resulting in decreased well yields, well abandonment and conversion back to dryland, the study says. Water use efficiencies will allow aggregate corn and cattle production to increase through the 2040s despite a reduction in groundwater supplies.
Reducing water use by 20 percent today would cut agricultural production to levels 15 to 20 years ago, the report says. That would extend peak agricultural production to the 2070s.
Farmers in the Texas Panhandle, squeezed for water by a three-year drought and a declining Ogallalla Aquifer, are experimenting with planting corn without watering the ground first. They are planting later in the season so they can tap the summer rain and switching to pivot sprinklers for more efficient, affordable watering.
The groundwater authority in the Panhandle limits how much water each farmer can draw from the aquifer. It initiated the demonstration pilot with 11 farmers who have been trying to make do with less water while still remaining profitable. Farmers, who draw more than half the water used in the region, are now subject to the same water restrictions as cities and industrial plants.
Some farmers and contractors in California also had their water supply cut this year because of an unusually dry winter. Following a wet start to the water year in November and December 2012, the January to March period was California’s driest on record, according to the US Department of the Interior.