History

The Oakdale Irrigation District (OID) was organized on November 1, 1909 under the Wright Act. The OID and its sister district, South San Joaquin Irrigation District (SSJID), purchased an old established system known as the Tulloch System. In the 1880’s Mr. Charles H. Tulloch purchased water rights and a ditch with a small diversion dam built by early miners for use in Placer gravel workings in the Knights Ferry vicinity. Local farmers extended the ditch, known as the Old Tulloch Ditch, down into the valley area to service 6,000 acres of farm land that included parts of SSJID and a small area around Oakdale. This was the beginning of OID and SSJID. This system was purchased in July of 1910 by OID and SSJID for a total price of $650,000. The two districts entered into a joint agreement on equal water rights and joint expenditures, with each paying half of the cost. Each district acquired vested water rights to the Stanislaus River aggregating 908.3 second-feet of natural flow diversion.

The districts abandoned the old miners’ diversion dam and in 1912 began construction of Goodwin Diversion Dam which was named for Benjamin Goodwin, then president of the SSJID board. The dam was constructed at a cost of $325,000 and was a double concrete arch dam, 80 feet in height above the river bed and 500 feet long on the crest. Water was first delivered in 1913 when Goodwin Dam was completed. From this dam, each district constructed main canals extending to their respective lands. On the north side, the two districts constructed a joint main canal of 1,200 second-feet designed capacity extending 4 miles from the Goodwin Diversion Dam to the Joint Diversion Works. This section of the canal is owned and operated in the proportions of 28% OID and 72% by SSJID. OID’s facilities consist of main canals on each side of the river. OID’s water is carried from the diversion works by the Littlejohns (Johnny) Creek approximately 1 mile, and at the Johnny Creek Dam is then diverted back into the North Main Canal. The North Main Canal extends from the joint diversion works approximately 15 miles down into the floor of the valley and the South Main is approximately 22 miles in length. From these main canals, approximately 250 miles of lateral ditches were built.

Until 1925, irrigation was dependent upon the natural flow of the river which was far from being adequate to irrigate the 20,000 acres. The two districts again joined hands and voted for $2,200,000 in bonds to build a storage reservoir of 112,500 acre-feet, known as the Melones Reservoir. From 1931 to 1938, the districts put in 25 deep wells to augment the water supply to meet the urgent demand for late summer water when extensive planting of Ladino Clover required water every 10 to 12 days.

The districts negotiated a contract with Pacific Gas & Electric (PG&E) for the sale of the falling-water benefits below the dam for hydro-electric power generation. PG&E agreed to pay each district $129,345 per year for a period of 40 years. The final payment under the contract made in 1967 completely amortized the bond issue without any tax burden upon the landowners in the districts. The reservoir was completed December 15, 1926, and Mr. R.E. Hartley served as Chief Engineer on the project.

By 1938, both districts found they were desperately short of irrigation water, and in searching for an answer to this problem, the idea of the Tri-Dam Project was born. The principal purpose of the Tri-Dam Project was to provide a supplemental water supply for the lands of OID and SSJID. Power generation was the secondary purpose, but an important one since it provided all of the revenue required to repay the capital investment, maintenance and operations costs, and is a supplemental income to the districts enabling them to maintain reduced water rates. In 1948, sites were approved at Donnells and Beardsley on the middle fork of the Stanislaus River, and Tulloch above Goodwin Dam. The two districts entered into a joint agreement to carry out this proposed Tri-Dam Project. Mr. Hartley, OID’s Chief Engineer, was one of the major figures in the development of the Tri-Dam Project. He was authorized as early as 1924 to travel by horseback into the Sierra Foothills to make a preliminary survey of the Beardsley Flat as a possible site for the project. After 31 years of continuous effort, he succeeded in reaching the goal.

The combined storage capacity for the 3 reservoirs is 230,400 acre-feet, with a combined power generation of 81,000 kilowatts. Additionally, in 1984, the Sand Bar Hydroelectric Powerhouse Project was completed and it is capable of producing 16,200 kilowatts.

Re-licensing of the Tri-Dam Project will occur in 2004. Because of deregulation, the chances are very slight that the districts will contract with PG&E as they did in the past. Many options are available such as those done by Modesto and Turlock Irrigation Districts.

This information was gathered from various files at Oakdale Irrigation District with “Histories of the Districts” and correspondence from Mr. Russell Hartley.