Annual ditch maintenance will shut down water flow

The Tuolumne Main Canal owned by Pacific Gas and Electric Company that conveys 95 percent of the Tuolumne Utilities District’s water supply will be shut down for annual maintenance from Oct. 18 through 25.

All ditches and flumes operated by PG&E, some of them dating back to the 1850s, will be drained and dried out.

TUD has asked the public to limit water use during the maintenance period to help maintain an adequate supply for drinking, sanitation and fire protection. Without water flowing through the ditches, available water comes from storage tanks and limited groundwater wells.

TUD said in a press release that, due to the ongoing Phoenix Lake Preservation and Restoration Project, all ditches in the district will be turned off during the main

tenance.

The $4.17 million project will remove 235,000 cubic yards of sediment from the Phoenix Reservoir east of Sonora, which will deliver an additional 150 acre-feet of capacity. TUD has said the project will improve water quality for thousands of TUD customers. The project is expected to be completed in October 2021 and will increase the capacity of the reservoir to 750-acre feet.

TUD said the public can conserve water by limiting outside watering, not washing vehicles, turning off automatic lawn and drip sprinkler timers and repairing water leaks.

They also requested the public continue conservation efforts for an additional week after the maintenance so the water storage supply can recover.

The Tuolumne Main Canal is about 16 miles long, extending from the base of Lyons Dam on the South Fork Stanislaus River to the junction with the Phoenix penstock that flows into Phoenix reservoir. TUD owns approximately 71 miles of ditches, flumes, pipes and tunnels that divert water from the PG&E infrastructure at various locations.

TUD entered into mutually exclusive negotiations with PG&E earlier this year to acquire infrastructure and pre-1914 water rights, including Pinecrest and Lyons reservoirs, the Tuolumne Main Canal and Phoenix hydropower facilities.

Negotiations, regulatory approvals and asset transfer may last up to three years.