Smith River Watershed Investigations

Science Center Objects

The Smith River watershed is an important recreational and agricultural area in Meagher and Cascade counties in west-central Montana. Thousands of visitors travel to the area annually to float and fish the Smith River. Additionally, most of the water used to irrigate 36,000 acres of the upper Smith River watershed is withdrawn from the Smith River or its tributaries. During a recent drought, streamflow was not sufficient to meet the needs of all irrigators and recreationists, and minimum streamflow for fish viability was not met on several occasions. Largely in response to the lack of available surface water for irrigation, some irrigators have switched to or proposed switching from flood to sprinkler irrigation, and some have considered using groundwater as a source of irrigation water. The effect of these changes in irrigation practices on the hydrologic system in the upper Smith River watershed is not well understood. Existing data are not sufficient to adequately describe the hydrologic system and the existing interaction between the surface-water and groundwater systems in the watershed.

Objectives:

  • Assess the groundwater and surface-water systems within the Smith River watershed including characterization of the hydrogeology, development of a conceptual groundwater-flow model, and characterization of streamflow.
  • Assess the interaction between groundwater and surface water along the Smith River and its major tributaries.
  • Estimate the water available in the system through development of a hydrologic framework and water budget.
  • Evaluate the consumptive use of irrigated water.
  • Provide large-scale background information that will improve the knowledge and understanding of the hydrology of the area and provide a basis for potential future studies of a more-detailed nature.