Gallatin Watershed - (Click Map To Enlarge)

Gallatin Watershed Features:

Located in southwest Montana.
1,162,295 acres (1,816 square miles)
Includes multi-jurisdictional boundaries: Gallatin, Park & Madison Counties in Montana and Yellowstone National Park, Wyoming.
Land ownership is approximately half public (federal, state and local government) and half private.

The Watershed

Part of the Upper Missouri River Basin, the Gallatin Watershed originates high on the Yellowstone Plateau in Yellowstone National Park and covers nearly 1.2 million acres (1,800 mi²). From spectacular mountain peaks, to lush valley bottoms, to arid sagebrush landscape, the watershed’s beauty is in its diversity. This beauty is driven by its climatic diversity, with the upper portion of the watershed receiving, on average, 300 inches of snow each year (approximately 50 inches rain), while the lower watershed near Logan averages about 12 inches of rain per year-nearly desert conditions.

The greater Gallatin watershed consists of two main river systems: The West Gallatin River (often referred to as the Gallatin River) and the East Gallatin River. The West Gallatin River originates in Yellowstone National Park and is 103 miles long. The East Gallatin River, which is 41 miles in length, originates in the Bridger Mountain Range on the eastern edge of the watershed. The watershed consists of 23 major water bodies totaling 394 miles of stream. Of these, 12 are listed as "impaired" by the Montana Department of Environmental Quality. Nine streams are categorized as having "insufficient data" to determine impairment. Two meet all criteria for their designated beneficial uses.

The Gallatin aquifer system is approximately 60 feet thick in the Four Corners area to over 400 feet thick around Belgrade. Regional ground water flow is southeast to northwest with all water (ground water and surface water) leaving the watershed at Logan. Except for the City of Bozeman, whose main water supply source is surface water, all other municipalities and County residents receive their drinking water from the Gallatin aquifer system.

A watershed rich in history, the Corps of Discovery (led by Lewis and Clark) marveled at the abundant wildlife and natural features along the Gallatin River on their return trip in 1806. Abundant wildlife attracted Native Americans to the watershed: Blackfeet, Crow, Bannock, Nez Perce, and Shoshone Indians all hunted and fought in the valley. By the mid-1800’s, settlers began modifying the landscape and hydrology by trapping beaver, digging irrigation canals, and draining wetlands. Over the years the river has seen a dramatic change in its use from transporting logs during the early 1900's to transporting rafts, kayaks and fishermen today.

Today’s challenges for the watershed are much different. Continued rapid and unprecedented growth is driving the conversion of land from rural to urban uses. Gallatin County’s current population is 73,000--a 34% increase in growth from 1990-2000. Eighty-thousand (80,000) acres of farmland were converted between 1997-2000 (Ag Census). Since 2000, the population has increased by almost 7,800 residents - an 11.5% growth rate. With as many as 5,000 homes planned for the Gallatin Valley in the next several years, the quantity and quality of our water and associated natural resources must be taken into account as we plan for the future of our watershed.