Three Forks of the Missouri

A view from a promentory known as Lewis Lookout, over the valley where the Three Forks of the Gallatin, Madison, and Jefferson Rivers join to form the Missouri River.

NPS

On July 25, 1805, Lewis and Clark reached the headwaters of the Missouri River, a major objective of the expedition. Here, the Gallatin, Madison, and Jefferson Rivers form the Three Forks of the Missouri. Continuing westward, the expedition proceeded up the Jefferson River.22

Water quality in much of the Missouri River watershed is badly degraded. Drought conditions, low snowpack, and warmer temperatures brought on by climate change have led to low flows and fishing closures on several rivers. The Gallatin River has experienced noxious algae blooms since 2018. In 2021, the Madison River brown trout population reached a twenty-year low. Meanwhile, water temperatures in the Jefferson River became dangerously high for trout survival, at the same time as algae and low water flow impacted the river. The State of Montana and the U.S. Bureau of Reclamation cooperated to produce a Missouri Headwaters Basin Drought Contingency Plan in 2021.23

Citations:
22 NPS, “Three Forks of the Missouri,” Pittsburgh to the Pacific: High Potential Historic Sites of the Lewis and Clark National Historical Trail, 2022, 72, https://www.nps.gov/lecl/getinvolved/upload/2022_LCNHT_HPHS_Report_508compliantUPDATE-2.pdf; Meriwether Lewis, July 25, 1805 entry, in Gary E. Moulton, Journals of the Lewis and Clark Expedition, https://lewisandclarkjournals.unl.edu/item/lc.jrn.1805-07-25.
23 Quincey Johnson, “Missouri River Headwaters Sub-Basin Report—Summer 2021” Upper Missouri Water Keepers, June 30, 2021, https://www.uppermissouriwaterkeeper.org/basinreport21/; Ann Schwend, “Missouri Headwaters Basin Drought Contingency Plan” (Helena: Montana Department of Natural Resources and Conservation, August 2021), https://dnrc.mt.gov/_docs/water/Planning_implementation_coor/MTDNRCMissouriHeadwatersBasin.Aug.2021.pdf.

Climate Change:Lewis and Clark Trail