2026 Phillips Reservoirs Project Documentation

This document is a technical drawing set for the 2026 Phillips Reservoirs project located in Phillips County, Montana, managed by the United States Department of the Interior, Bureau of Land Management, Malta Field Office. The project encompasses rehabilitation work on three reservoirs: Flintstone Reservoir, Hump Reservoir, and Bison Store Reservoir. The drawing index indicates six sheets total, including location maps, plan views, spillway cross sections, and erosion control mat details.

The primary scope of work involves rehabilitation of the Flintstone Reservoir spillway and embankments at the Hump Reservoir. For Flintstone Reservoir, work includes removal of riprap from the spillway headcut and stockpile for reuse, removal and disposal of existing spillway fabric, excavation to sound embankment, installation of erosion control matting, and construction of a new dam embankment with crest elevation of 102.6 feet. The Hump Reservoir work focuses on dam embankment cross-section modifications with new crest elevation of 100.7 feet and removal of woody vegetation from the upstream embankment face. Specifications detail erosion control mat installation with minimum 18-inch end anchors and 12-inch side anchors, compacted subgrade preparation, and anchor trench construction. The project includes detailed engineering drawings showing spillway profiles, riprap apron cross sections, and embankment details with specific elevation requirements and slope specifications.