Water in the Nebraska Sandhills is plentiful. It accounts for the continuity of human activity and the abundance of plants and wildlife. Precipitation, groundwater, streams, lakes, wetlands, and human-made water sources are connected and work together in a complex system, providing life for plants, animals, and people.
The primary source of water in the area is precipitation. Due to the high infiltration rates of the sandy soils and an impermeable layer of bedrock, the groundwater reservoir is vast. Runoff is rare and only occurs during large and fast precipitation events. Most of the precipitation that falls in the Sandhills percolates through layers of sediment and ends up in the aquifer. In some areas, the aquifer is close to the surface, and in other areas, it is deep underground. The topography of the dunes influences this depth. The groundwater reservoir regulates the hydrology of the Sandhills more than any other source. It, along with precipitation, feeds the streams, lakes, wetlands, and human-made water sources.
Streams are unique in their origin and in the fact that they have relatively very few tributaries, but flow at a steady rate. Major rivers originating in the Sandhills include the Snake, North Loup, Calamus, Middle Loup, and Dismal. The Niobrara River flows through the Sandhills, but it originates in the high plains of Wyoming. Streams and creeks feed into these six main rivers. Sandhills rivers and creeks are all supplied by groundwater resulting in very little erosion or head cutting. However, ditching and straightening streams for agricultural purposes has lead to down cutting and changes to the overall hydrology of some localities. The Sandhills Task Force and its partners work with private landowners to restore the natural elevation and winding nature of these altered creeks.
The number and size of lakes and wetlands vary spatially across the Sandhills, as well as seasonally and annually. Lakes occur in many locations, including between dunes, at stream headwaters, and in large basins. Rainfall events directly influence the primary source of water for lakes and wetlands and lake levels. Indirectly precipitation affects lakes and wetlands by recharging the groundwater reservoir. Sandhill lakes are shallow; the deepest, Blue Lake in Garden County, is only 14 feet deep. Most have depths of less than five feet, resulting in a gradual change in vegetation from lake plants to marsh and meadow plants. It may be hard to distinguish where lakes end, and the marsh or wetland begins.
“…the lakes and wetlands are frequented by waterbirds and shorebirds of all sorts and are often dotted with the domes of muskrat houses. Most of these bodies of water are manifestations of a groundwater reservoir that contributes to a sense of well-being in what would otherwise be an environment much more hostile to life of all kinds.”An Atlas of the Sandhills
Humans have installed windmill and tank ponds for use by domesticated livestock. Wetlands may result from spillage and overflow, which create habitat for many different types of plants and animals. Snails, insects, and tiger salamanders live in tanks and livestock ponds. Birds can transport eggs of these species on their feet and create new biological communities in isolated areas. Damselflies, dragonflies, and aquatic beetles benefit from these unique Sandhills ecosystems, which are directly fed by the fresh groundwater found under the dunes.
Water in the Sandhills is a unique and complex system. Groundwater, lakes, wetlands, and human-made water sources are recharged directly by precipitation. The soil’s natural ability to filter percolating water through its layers increases the quality of this natural resource. The sizeable underground aquifer feeds the streams, lakes, wetlands, and human-made water sources. Each water source features a unique biological habitat. Still, they are all connected in the complex hydrological cycle found in the Sandhills.