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Welcome to the Tri-Dam Project

Operations and maintenance of the Donnells, Beardsley and Tulloch projects, located on the Middle Fork of the Stanislaus River in Tuolumne County, California.

Tri-Dam Project is a partnership between the Oakdale Irrigation District and the South San Joaquin Irrigation District. Together they developed, operate and maintain the Donnells, Beardsley and Tulloch projects including the dams, tunnels, penstocks, powerhouses, communications systems, and general offices. These facilities are located on the Middle Fork of the Stanislaus River in Tuolumne County, California.

The “Upper Works” include Donnells and Beardsley dams, reservoirs, powerhouses and appurtenant facilities. The “Lower Works” refer to the Tulloch development below Jamestown reaching into both Calaveras and Tuolumne Counties.

Tri-Dam Project is governed by a joint board of directors composed of the five member boards of the two Districts. The day to day activities of Tri-Dam Project and Tri-Dam Power Authority are managed by a General Manager who reports to the board. The administrative offices of Tri-Dam Project are located in Strawberry, California.