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Water: Nonpoint Source Success Stories

Fort Peck Assiniboine & Sioux Tribes


Demonstrating the Effects of Managed Grazing

Improved water quality is a major concern for the Fort Peck Assiniboine and Sioux Tribes of the Fort Peck Reservation in northeastern Montana's glaciated plains, and nonpoint source program management is the method most likely to serve their goal. Grazing is a major contributor to nonpoint source pollution on the reservation. Most grazing units follow waterways because livestock are dependent on the streams for their water supplies. More than that, however, livestock grazing makes a dual contribution to the tribes' economic livelihood: the tribes produce livestock and lease grazing lands to other ranchers.

The demonstration of a managed grazing system, a section 319 project, is underway as a first phase of a full-scale water quality protection plan for the reservation. The system will be demonstrated in the Little Porcupine Creek watershed, which is used for grazing from summer through fall.

The creek itself, a Class 1 Warm Water, supports several beneficial uses: aquatic life, secondary contact recreation, and agriculture. Three monitoring locations will be used to help project managers gage the effectiveness of the best management practices (BMPs). Approximately 80 percent of the watershed is native rangeland which produces approximately 0.25 animal unit months per acre. The normal management of the range is to graze cow/calf pairs for 5.5 months between May 15 and November 1. Generally the livestock are unconfined and tend to concentrate in the riparian areas in the heat of the summer.

At its upper end, Little Porcupine Creek has lost almost all integrity as uncontrolled grazing stripped its banks of riparian vegetation. Though the stream flows mostly underground, appearing only in isolated pools in the flat valley, it still serves as the only livestock watering source for the range.

Grazing along the riparian corridor has been especially heavy. Woody species, including trees and shrubs, have been reduced to almost nothing, degrading the landscape and increasing stream temperatures, sedimentation, and conductivities. Summertime water temperatures average 22 C. The stream channel bottom is over 50 percent silt.

Short-term goals for this project include the restoration of a healthy riparian zone and improving water quality at the long-term monitoring sites located in this range unit. Indicators for grading water quality and riparian improvement include increasing the biological condition category from severely impaired to moderately impaired and increasing the habitat supportability ratings from nonsupporting to partially supporting.

CONTACT: Deb Madison
Fort Peck Office of Environmental Protection
(406) 768-5155, ext. 399

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