Watercourse Mapping in the Gallatin Valley

The Lower Gallatin Watershed is woven with natural streams and man-made ditches. This network of watercourses is very dynamic and interconnected, both hydrologically and culturally. As our community and the climate changes, it becomes increasingly important to manage the many miles of this distribution system collectively. Unfortunately, much of the existing irrigation infrastructure is antiquated, and watercourse maps are outdated, inaccurate, and incomplete. The first step towards sustainable water distribution for a healthy and productive landscape is to know where and what watercourses are, so that the many stakeholders involved can better understand how they are connected, what regulations apply, and which best management practices are appropriate. 

Watercourse Mapping Dashboard

3D Hydrography Program (3DHP) is a national program managed by the USGS to acquire high-resolution elevation data. 3DEP will improve data accuracy and provide more current data than is available in the National Elevation Dataset.

The Gallatin Water Collaborative is working with the USGS to map areas in the Gallatin that are experiencing the most growth and impacts to streams and ditches. Current priority subwatersheds for mapping include Hyalite Creek, Upper and Lower East Gallatin River. 

With additional funding and partner support, Collaborative stakeholders hope to map the extent of Gallatin County (including Three Forks), the irrigation ditch network, and the upper reaches of the watershed. A comprehensive overhaul of watercourse maps would streamline data management and highlight the connected nature of hydrology from upstream to downstream and across subwatersheds. 

Click on the image to view the Montana 3D Hydrography
Program Planning Dashboard.

Help to Support Mapping Across the Entire Gallatin Watershed

Thanks to the following partners for helping to financially support the Watercourse Mapping project: USGS, Gallatin Conservation District, Montana Department of Environmental Quality, and Custer Gallatin National Forest. If your group is interested in supporting this work, contact Lilly McLane at lilly@gallatinwatershedcouncil.org

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