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DNRC Headquarters
1539 Eleventh Ave. Helena, MT 59601
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Lolo Creek Pilot Basin Study

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Project Description

The purpose of the Lolo Creek Pilot Basin Study is to provide useful information on water resources in the Lolo Watershed while updating the DNRC Water Management Bureau’s hydrologic investigation methods by incorporating new datasets, remote sensing, integrated hydrologic modeling, real-time water data, and collaboration with local stakeholders. Multiple water uses, recreators, and aquatic life all depend on Lolo Creek for water. In recent decades, the creek has gone dry near its confluence with the Bitterroot River, raising concerns about water supply issues in the watershed. This project was a collaborative effort between the DNRC and Montana Bureau of Mines and Geology (MBMG). MBMG is conducting a Groundwater Investigation Program (GWIP) study of Lolo Creek in addition to DNRC's study. DNRC's role was to describe the hydrology and water use at the watershed scale as well as provide surface water data for MBMG's groundwater investigation. As part of their GWIP study, MBMG will look at specific scenarios that might cause Lolo Creek to dry up as well as provide groundwater data for DNRC's study. DNRC and MBMG have both worked closely with the Lolo Watershed Group to design and conduct this study.

Study Goals

  1. Describe the hydrology, water use, and provide recommendations/tools for stakeholders to make informed water management decisions in the Lolo Watershed as well as aid in implementing the Lolo Watershed Restoration Plan.
  2. Develop new study methods that include using satellite derived hydrology and meteorology datasets, watershed modeling, and real-time water information to accomplish Goal #1.

Study Objectives

  • Develop a comprehensive water balance for the watershed.
  • Analyze past, present, and projected climatic patterns and their effects on the local water cycle.
  • Provide estimates of future changes in water supply and water use.
  • Summarize hydrologic data and analyses in a report that communicates both a general and detailed understanding of the Lolo Watershed.
  • Provide management recommendations that support drought planning, improvements in water use efficiency, and water use administration.
  • Support the MBMG ground water investigation.


Final Report

The Lolo Creek Pilot Basin Study report is being written as a 2-part series.

  • Part I - Describes the hydrologic cycle of the Lolo Watershed and basin-wide water use for a four year period (2016-2019). Finalized February 18, 2022 - download report using link below.
  • Part II - Provides watershed modeling results for past streamflows and landscape water balance components such as evapotranspiration and soil moisture. This allows analysis of long-term trends to explore management options under various water supply scenarios.

  Report Downloads

   Lolo Creek Pilot Basin Study Part I - Hydrologic Investigation Report HI220218-WMB.

   Lolo Creek Pilot Basin Study Part I Appendices.

Data Downloads and Products

Contact Information

Todd Blythe


Local Weather Data

Montana Climate Office

Natural Resources and Conservation Service

Lolo Pass Snotel