Protecting Groundwater in the National Parks, for People and Ecosystems

Imagine a hot summer day in a desert park. After hours on the trails, you fill your water bottle at the visitor center spigot and find some shade. That easy refill hides a great deal of planning and research — and a close connection between the water you drink and the natural and cultural features that draw people to national parks.

A young visitor fills a bottle with Roaring Springs water on the North Rim of Grand Canyon National Park. NPS/Michael Quinn

A balancing act

Across its more than 430 park units, the National Park Service manages countless streams, springs, wetlands and other water resources. Its founding mission, set out in the Organic Act of 1916, is "to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations." For water, that means keeping supplies sustainable for natural resources, cultural resources and park operations alike. In dry parks, where rain is scarce and groundwater meets most human and ecological needs, that balance is delicate — and climate change and rising demand make it harder.

Why groundwater matters

Groundwater moves underground through cracks and pores in rock and sediment, in storage systems called aquifers. It makes up about 30% of Earth's fresh water; about 69% is locked in glaciers and ice caps, and the remaining 1% is in lakes, streams, swamps, permafrost and the air. People reach it through wells and springs, while plants and animals use it where it flows near or at the surface.

Roaring Springs, seen from the North Kaibab Trail, supports aquatic life and supplies all the drinking water for visitors and staff at Grand Canyon National Park. NPS/Michael Quinn

In the parks, groundwater feeds lakes, streams, wetlands, estuaries, springs and geothermal features such as Yellowstone's geysers and hot springs. Groundwater-dependent ecosystems rely on it to exist. It supplies the "baseflow" that keeps many rivers running after rains and snowmelt end, especially in drought, and it keeps springs and wetlands wet year-round for plants and animals that cannot survive in drier places. It also provides park water for drinking, cooking, cleaning and firefighting, and sustains culturally important places, from the historic orchards of Manzanar National Historic Site to the anchialine pools at Kaloko-Honokōhau National Historical Park that made settlement possible in West Hawaiʻi.

Groundwater is easily overused, as individuals or groups draw on it for their own benefit at the common expense. Global extraction has more than quadrupled in the last 50 years, harming groundwater-dependent ecosystems and their native and endangered species, as well as disadvantaged communities.

Two new projects

The Inflation Reduction Act of 2022 made $210 million available to the Park Service for resilience, restoration and environmental planning. Many park water supplies are vulnerable to climate change, aging infrastructure, population growth and development, yet few had been evaluated. Two IRA-funded projects are now doing that.

NPS and Utah Geological Survey staff observe a spring and its groundwater-dependent ecosystem at Arches National Park. NPS/Tyler Gilkerson.

Staff measure groundwater levels at the Alpine Visitor Center's supply well in Rocky Mountain National Park. NPS/Derek Schook

Water for People

Led by the NPS Water Resources Division and Climate Change Response Program with Colorado State University and the Department of the Interior's Office of the Solicitor, this project assesses how vulnerable park water supplies are to climate change and focuses effort on the most at-risk systems.

• The team gathers all existing data on a water source and compares local hydrology with past climate to see how sensitive it is to temperature and precipitation.
• It then projects how a range of future climates could affect the source's adequacy.
• Where a supply may fall short, it develops adaptation strategies, such as more conservation, fixing leaking pipes, more storage for longer droughts, or switching to less vulnerable sources.
• The Solicitor's office reviews the parks' water rights, their vulnerability to curtailment or legal challenge, and legal strategies to strengthen supply.

NPS Water Resources Division staff conduct a pumping test at Manzanar National Historic Site to determine the sustainable yield of a new groundwater supply well. NPS/Gilkerson.

In 2023–2024 the project assessed Bryce Canyon National Park and began building a Park Service water supply database, with Cedar Breaks National Monument, Zion National Park and others to follow in 2024. NPS hydrogeologist Tyler Gilkerson explained that these parks were chosen for their diverse water sources, abundant data, major infrastructure needs and possible future climates, and that with more than 6 million visitors a year and the threat of longer, more severe droughts, assessing their water supplies is critical.

Water for Ecosystems

With the University of Nevada–Reno's Desert Research Institute, the same NPS offices are also protecting places where groundwater naturally reaches the surface. These spots are often backcountry water sources, biodiversity hotspots, homes of rare and endemic species, places of cultural and spiritual importance, and scenes of exceptional beauty — and the Park Service manages many of the country's few remaining unaltered springs, especially in the arid West. The team is building a geospatial database and web application of key groundwater-dependent ecosystems, assessing their vulnerability to climate change, and identifying restoration opportunities, data gaps and monitoring priorities, again with legal support on water rights.

"Groundwater-dependent ecosystems are considered sentinel sites for evaluating the effects of drought and climate change on the broader landscape," said Steve Rice, who leads the Water Resources Division's groundwater program.

Volunteers conducting a spring inventory at Grand Canyon National Park. NPS/Steve Rice

Sources

• National Park Service, "How the NPS is protecting groundwater for people and ecosystems": https://www.nps.gov/articles/how-the-nps-is-protecting-groundwater-for-people-and-ecosystems.htm Pictures an earlier version of this page left out were restored on 2026-09-26.