The Oakdale Irrigation District (OID) and South San Joaquin Irrigation District (SSJID) joined forces in the late 1930s to design the Tri-Dam Project in an effort to satisfy the need for more water for irrigation, as both of the districts’ existing infrastructure was insufficient to meet the growing demand for water.
On January 13, 1948, the districts publicly announced their intent to develop the Tri-Dam Project, which consists of a series of dams, reservoirs and power plants at the current sites of Beardsley, Tulloch and Donnell reservoirs on Middle Fork of the Stanislaus River, as well as improvements to older developments.

Over the next eight years, the districts battled a series of financial setbacks and conflicting claims to the sites where they desired to build the dams.
For instance, the Tuolumne County Water District had a prior application for the Donnells site.
In 1953, the conflict over water rights was settled with the irrigation districts receiving the water rights.
 As part of the agreement, Donnells and Beardsley reservoirs had to be used for power generation except in the case that water had to be released to enhance downstream flows.
After the rights claims issues were resolved, the districts set out to find funding for the project and, after much difficulty, settled on selling bonds.
The OID and SSJID, with the help of Pacific Gas and Electric Company (PG&E), successfully sold bonds to fund the Tri-Dam Project and started construction of the dams in 1955.
The districts paid off the bonds by entering into a contract with PG&E in which the OID and SSJID sold the electricity generated by the dams’ hydropower facilities to PG&E over a fifty-year period; the contract ended in 2004.
The Oakdale Irrigation District (OID) and South San Joaquin Irrigation District (SSJID) joined forces in the late 1930s to design the Tri-Dam Project in an effort to satisfy the need for more water for irrigation, as both of the districts’ existing infrastructure was insufficient to meet the growing demand for water. On January 13, 1948, the districts publicly announced their intent to develop the Tri-Dam Project, which consists of a series of dams, reservoirs and power plants at the current sites of Beardsley, Tulloch and Donnell reservoirs on Middle Fork of the Stanislaus River, as well as improvements to older developments.
Over the next eight years, the districts battled a series of financial setbacks and conflicting claims to the sites where they desired to build the dams. For instance, the Tuolumne County Water District had a prior application for the Donnells site. In 1953, the conflict over water rights was settled with the irrigation districts receiving the water rights.  As part of the agreement, Donnells and Beardsley reservoirs had to be used for power generation except in the case that water had to be released to enhance downstream flows. After the rights claims issues were resolved, the districts set out to find funding for the project and, after much difficulty, settled on selling bonds. The OID and SSJID, with the help of Pacific Gas and Electric Company (PG&E), successfully sold bonds to fund the Tri-Dam Project and started construction of the dams in 1955. The districts paid off the bonds by entering into a contract with PG&E in which the OID and SSJID sold the electricity generated by the dams’ hydropower facilities to PG&E over a fifty-year period; the contract ended in 2004.
Donnells Dam