Groundwater Program

Mission Statement

“High quality groundwater on the Nez Perce Reservation provides nearly 100% of the potable water supplies for the Nez Perce people. The Lapwai Valley Aquifer is a portion of the federally designated Lewiston Sole Source Aquifer and scientific studies have documented that streams and groundwater are hydrologically connected. Our mission is to protect high quality groundwater from degradation and to restore contaminated groundwater to beneficial use.”

Hydrogeologic Background

Geologically, the aquifers are contained within stratified basalts of the Columbia River Basalt Group that have been subsequently folded and faulted. Aquifers occur between the basalt flows and are localized primarily along permeable basalt flowtops. The interiors of the flows consist of massive basalt with relatively little water passing vertically between the basalt flows. This results in a stratification of aquifers that typically function independently of each other. The best example of this vertical separation of aquifers is based on an administrative declaration of a Ground Water Management Area for the Lindsey Creek Aquifer, which is producing its water from the Saddle Mountain and Wanapum Basalts formation.


Pollution prevention is the most effective method of protecting valuable high quality groundwater resource through implementation of regulatory standards and best management practices to be applied to all activities by the NPT Tribe, industry, agriculture, municipalities, private homeowners, and public transportation corridors within the Clearwater River Watershed.

mm Science-based soil and groundwater assessments and environmental cleanups will strive to remove  contamination where feasible and minimize damages to human health and the environment

mm Establishing groundwater monitoring points for both water quality and quantity (e.g. water level)  will provide a long term record that will be useful to the Tribe in trend analysis and potentially useful as a predictive tool useful to land managers


Although they’ve been in technology we use everyday since the 1940’s, forever chemicals that are extremely resistant to degradation in the environment, have just been making headlines in the last few years. Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that includes PFOA, PFOS, GenX, and many other chemicals. PFAS have been manufactured and used in a variety of industries around the globe, including in the United States since the 1940s.

Need to Report Hazardous Materials Dumping and Spilling?

Contact The Tribal Hazardous Environmental Response Team (HERT), your local fire department, and State Communications at 1-800-632-8000, or (208) 846-7610.



Brownfields are real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant. This program is funded by CERCLA 128(a)/ Brownfield’s Tribal Response Program, and includes:

• Conducting timely survey and inventory of brownfield sites,
• Providing oversight and enforcement authorities,
• Creating meaningful opportunities for public participation,
• Authorizing cleanup approval and verification that a cleanup is complete, and
• Establishing a public record documenting the work conducted in the previous year and the
planned  work  for the current year.

Leaking Underground Storage Tanks (LUST’s)

The Groundwater Program’s goals are to cleanup leaking underground storage tank (LUST) sites to restore and protect groundwater resources and create a safe environment for those who live or work around these sites. This program is funded under the Resource Conservation Recovery Act (RCRA) and includes:

LUST prevention, and LUST assessment and cleanup.