Damaged by Severe Winter Weather, Main Tuolumne Canal Repairs Get PG&E’s Full Focus

This week’s severe winter storms wreaked havoc across the Sierra Nevada foothills, closing roads, knocking down trees and causing power outages.

The storms also resulted in significant damage to the Main Tuolumne Canal. The approximately 14-mile canal runs between Lyons Reservoir and the Phoenix Penstock in the forested foothills of Tuolumne County.

Due to the significant damage from the storms, PG&E reduced, and then ultimately stopped, flows to the canal due to fallen trees and heavy snowfall that would have prompted the canal to overflow. This happened on Tuesday (Feb. 17) when PG&E’s Tiger Creek Switching Center was given the order, and the head gate to the Main Tuolumne Canal was closed, stopping all flows.

A helicopter patrol on Friday (Friday, Feb. 20) confirmed the damage. Two flumes need repairs, including one with five complete breaks. Approximately 200 fallen trees are atop the canal and flumes. There are two to four feet of snow on sections of the canal. On top of that, additional rain and snow are in the weather forecast for the area in coming days.

The water from the canal goes to the Tuolumne Utility District (TUD). This canal is the primary drinking water source for 90% of Tuolumne County. Sonora, the county seat whose Gold Rush history earned it the name “Queen of the Southern Mines,” is home to approximately 5,000 people.

In response to this critical situation, PG&E activated Power Generation Incident Management Team 3 to focus on making repairs so that we can restart water flowing to TUD.

“Damage is significant, weather and access continue to be issues and we’re working against a deadline,” said Sam Garcia, the Incident Commander for IMT-3. “But we’re gathering the right people and the right tools, and we have an unwavering focus on safety making these needed repairs. Our customers need us, and this is what we do.”

PG&E continues to work with stakeholders, including the TUD and local officials, to keep them informed of the damage, the timeline and the work ahead.