“We’re always so conscious of water here, because of the livestock and cattle. Is there enough rain to produce grass? Are we going to dry out? Is the wind going to blow the windmills so the tanks fill? Water has always been a huge part of our life.”—Sue Ann Switzer
Much of the water in Sandhills’ rivers like the North Loup originate as groundwater from the Ogallala Aquifer. Photo by Michael Forsberg.
The water supply in the Sandhills depends on local precipitation, which is relatively low. Yet, there are several rivers, including the Niobra
ra, Dismal, and Loup Rivers that originate in the Sandhills, more than 2,000 shallow lakes, and over one million acres of wetlands in the areas between the dunes. Even during periods of drought, the Sandhills maintain reliable supplies of water. This oddity is explained by the presence of porous sand dunes that overlie thick deposits of sands and gravels. Together these porous materials act like a giant sponge, soaking up rainwater to refill (or “recharge”) the massive groundwater reservoir called the Ogallala Aquifer.
Sandhills Water Cycle
When precipitation is high—particularly in the summer months—the water table rises to near or above the ground surface increasing the size of lakes, wetlands, and sub-irrigated meadows. Rainfall, in turn, supports the prairie vegetation as evaporation from the lakes and wetlands increases local humidity and rainfall, providing additional moisture for adjacent dune vegetation. In drier years, the number and size of the water bodies decrease, but because the groundwater reservoir is so large, some water bodies remain.
On the Switzer Ranch, cattle have access to creeks, lakes, and groundwater pumped to the surface by windmills and stored in stock tanks. Although wind-driven machines have been used in many forms since Ancient Greece, Daniel Halladay invented the first American windmill in Connecticut in 1854. His windmills—and similar designs that followed—have blades or sails that, when turned by the wind, crank a pump carrying groundwater to the surface. This water is channeled into a stock tank to provide drinking water for cattle and livestock on the range where a reliable source of water is unavailable. This type of windmill proliferated on the arid Great Plains in the 1870s and today remains an iconic fixture in the Sandhills.
The Switzers depend on sub-irrigated meadows found in the areas between the sand dunes where groundwater from the Ogallala Aquifer is at or near the surface. Plant roots easily reach this nearly constant supply of groundwater, allowing prairie vegetation to thrive in an otherwise semi-arid environment. These meadows are ideal for grazing cattle. Ranchers hay them in the summer months, and the hay bales are dried and stored to feed wintering cattle. Ranchers may also use center-pivot irrigation in drier meadows to increase hay production or when drought years leave the sub-irrigated meadows dry.