Billings, Yellowstone County

Background

The Billings area has experienced sustained, consistent growth and urbanization for the last 60 years. The number of housing units west of the core downtown area has grown from 11,000 in 1960 to 30,000 in 2020; a rate of over 300 residences per year. Most new developments are in areas beyond city services and depend on wells for drinking water and septic tanks for wastewater treatment.

To forecast the need for future city services (water, sewer, and storm), city and county officials must have a better understanding of the replenishment of water to the local aquifer contributed by agricultural irrigation and canal seepage, in addition to how land use change will affect the shallow aquifer.

Purpose

Evaluate the capacity of the aquifer to support future groundwater development in west Billings and identify the extent and source of nitrates in the study area.

Project Scope

Groundwater quantity:

1) Identify and quantify groundwater recharge from natural sources and agricultural practices.

2) Develop conceptual and numerical groundwater models to evaluate the effect on groundwater from land use change from agriculture to residential.

Groundwater quality: Define the role of agriculture practices and septic systems on groundwater quality. Identify nitrate distribution in groundwater and likely sources.

Project Status

Field work concluded in 2023. The work will be presented in three reports: a report detailing the water budget and flow modeling, a report summarizing the water quality and nitrate evaluation, and an isotope characterization study. The reports are scheduled to be published at the end of 2025.

Project Reports

• Billings intro fact sheet: June 2022
  View Report

Project Personnel

Elizabeth Meredith	Project Lead, Research Hydrogeologist
Kurt Zeiler	Associate Research Hydrogeologist, Groundwater Modeler
Skye Keeshin	Professional Scientist Research Hydrogeologist
Brett Oliver	Assistant Research Hydrogeologist, Groundwater Modeler
Todd Myse	Associate Research Hydrogeologist
Ann Hanson	Assistant Research Hydrogeologist

Presentations

• GWIP West Billings Project - Groundwater Flow Model Update. Presented to Yellowstone County Planning Board, February 11, 2025.
  View Presentation
• Ground Water Investigation Program: Groundwater Investigation of the Billings Aquifer. Presentation to the Montana Association of Planners Annual Conference, September 27, 2022, Billings, Montana.
  View Presentation

Link to Project Data

Data collected for this project can be accessed through the Ground Water Information Center (GWIC) database:

Download project data from GWIC