Chapter 5: Water Systems
Key Messages
- Changes in precipitation impacting water availability intersect multiple issues, including energy, health, agriculture, and more.
- Nebraska's residents and agriculture sector rely heavily on the state's groundwater resources for irrigation and drinking water.
- If appropriately managed, groundwater will continue to be Nebraska's best resource for resiliency against future climate change.
- Climate change will have complex impacts on Nebraska's water, likely affecting both groundwater and surface water quantity and quality. These impacts will ripple throughout Nebraska's economy, communities, and environment.
- With climate change, irrigation water demand will likely increase as the growing season becomes longer and the rate of evapotranspiration increases.
- At the state level, the trends in groundwater-level changes tend to follow the trends in precipitation.
- Drought impacts on Nebraska's groundwater and surface water may be more severe as the climate warms.
Economic and Social Importance of Water in Nebraska
Nebraska uses its water resources in diverse sectors. Water is vital for energy production, drinking, recreation, and irrigation for agriculture. For recreation specifically, the state has activities such as fishing, swimming, outdoor education, hunting, and boating, which are estimated to be worth ~$4 billion annually and supply over 24,000 jobs. Activities relating to the sandhill crane migration alone yield over $17 million. Historically, the state's rivers and streams have been used for navigation, hunting, and settlements by indigenous peoples like the Lakota, Ponca, Pawnee, and Plains Comanche. These same water resources were also pivotal in early agriculture and commercial growth. Nebraska's rivers drain west to east toward the Missouri River. Major river basins from North to South include:
- White River and Hat Creek
- Niobrara River
- Missouri River tributaries
- Elkhorn River
- Loup River
- Platte River
- Blue River
- Republican River
Nebraska has a history of flooding and drought events. With the changing climate, there will be more extreme wet and dry periods. This will have both direct and indirect impacts on the state's access to water. Moreover, the combination of more extreme precipitation, wetter springs, and wetter, warmer winters will lead to more frequent major flood events, increasing economic and recovery costs.
Water Management
Since water is a shared asset, its management in Nebraska has shifted from independent management toward more collaborative. As a result, there is a system in which many organizations and agencies need to coordinate and collaborate with one another. Organizations include the Nebraska Department of Natural Resources (NeDNR), Nebraska Department of Agriculture (NeDA), Nebraska Department of Environment and Energy (NDEE), and the Natural Resource Districts (NRDs). In the state, there are 23 local NRDs that were developed in the 1970s to help manage the state's groundwater. The NRDs use incentive programs, regulations, water allocations, and moratoriums to help reduce overusage of water resources. The NeDNR administers the surface water quantity rights and how water is allocated among neighboring states. Nebraska has interstate agreements with Wyoming, Colorado, and Kansas. The groundwater in the state works through granted correlative rights, meaning the public has coequal rights to the resource. The direct regulation of groundwater withdrawal is difficult because the time between policy implementation and groundwater changes spans years and makes forecasting long-term supply changes difficult.
Nebraska's groundwater is part of a greater aquifer known as the High Plains Aquifer (HPA), also called the Ogallala Aquifer. Nebraska underlies around 36% of the total area of the HPA, with other states like South Dakota, Kansas, Oklahoma, Texas, Wyoming, Colorado, and New Mexico being other members. Around 88% of Nebraskans rely on this groundwater as a domestic water source.
The depth of groundwater, distance from the surface to the groundwater, historically had minimal drastic changes, especially before widespread irrigation development. Changes to the groundwater levels in aquifers are measured by comparing current annual spring levels to predevelopment levels. Using these measurements, the water levels have steadily declined in western Nebraska. Conversely, in the sandhills region, water levels have steadily risen since at least the 1970s. Even with decent water levels, agriculture is not widespread in that area due to nutrient-poor soil. In years with above-average precipitation, less supplemental water is pumped for irrigation, allowing for greater aquifer recharge, raising the water level. In years with below-average precipitation, more water must be pumped, allowing less net recharge, lowering water levels. Water level changes from below-average precipitation have doubled in comparison to events of above-average precipitation.
Bodies of Water in Nebraska
Nebraska has over 2,000 natural lakes and over 1,000 reservoirs and sandpit lakes. An assessment of 45 lakes using the Trophic State Index showed that 43 of the lakes had levels of hypereutrophic or eutrophic conditions. Eutrophication, having too many nutrients in a body of water, usually from runoff, has caused dense growth in vegetation and algae, which removes oxygen and lowers the habitat quality for animals. Eutrophication threatens both wildlife and recreation. There is an increasing nitrogen trend in most river basins in the state. Conversely, phosphorus trends are stable or improving. The continuous nutrient loading and warming climate ultimately threaten ecosystem services that wildlife and people rely on. Surges in nutrient runoff from major precipitation events will ultimately accumulate agrichemical leaching into surface and groundwater in the state. Wetland ecosystems help recharge groundwater, filter pollutants, and manage flood storage. Moreover, it also provides habitat for crucial wildlife and plays a key role in greenhouse gas cycling. These carbon sinks are declining due to urbanization and invasive species. Although Nebraska has lost 35% of its wetlands in the last 200 years, it has had the largest acreage of wetlands among its neighboring states.
The surface water and groundwater are physically and legally connected. They need limitations in place to help mitigate overuse. Private wells are not regulated so owners are responsible for monitoring and treatment of their own water. For other water resources used as drinking water, the Environmental Protection Agency (EPA) oversees the maximum contaminant levels. The NDEE handles potential point sources of pollution in water, specifically in industrial and livestock facilities. The NRD handles non-point sources like field agrichemical applications and erosion. The US Army Corps of Engineers (USACE) oversees projects along the Missouri River, the primary navigable river route in Nebraska, stabilizing its banks, creating clear navigable channels, and managing its flow. Historically, work on the river has altered the river's edge habitat and disturbed natural channel processes, but there has been recent effort to re-naturalize river edges. This has assisted the reintroduction of habitat and natural methods of flood mitigation. With changing flow conditions and water quantity from the changing climate, this means river travel can become more unsafe or unsuitable, which could have vast economic consequences.
Importance in Agriculture
Agriculture is the main driving force of Nebraska's economy. Farmers and ranchers have historically been stewards of the land, being directly affected by environmental changes. Since rain varies across the state, some farmers rely on groundwater-fed irrigation systems and supplemental crop rotation. The development of wells for irrigation has expanded greatly since the 1950s, with 2024 having over 97,000 irrigation wells registered in Nebraska. In 2022, of 9.4 million acres of irrigated cropland, over 9 million acres were irrigated using groundwater. With more high-capacity wells, the more severe the impacts of drought. Moreover, a longer growing season and higher rates of evapotranspiration may increase the demand for irrigation water.
Aquifer Basics. (2025). In Ku.edu. https://www.kgs.ku.edu/HighPlains/HPA_Atlas/Aquifer%20Basics/index.html
Groundwater recharge and discharge. (2024). In USGS. https://www.usgs.gov/media/images/groundwater-recharge-and-discharge
Helmenstine, A. (2023). What Is Eutrophication? Definition and Explanation. In Science Notes and Projects. https://sciencenotes.org/what-is-eutrophication-definition-and-explanat…
