TRT Proposes Near-Term Relief for the Tuolumne

By Peter Drekmeier

In December 2018, the Tuolumne and several other rivers received a promising holiday gift from the State Water Board when it adopted higher instream flow requirements for waterways in the San Joaquin Basin. Unfortunately, we’re still waiting for the water to materialize.

Lawsuits and the State’s focus on Voluntary Agreements have delayed implementation of the Bay Delta Water Quality Control Plan. A State lawsuit over the Trump Administration’s bogus “scientific” study that concluded more water could be pumped from the Delta without harming endangered species has added to the stalemate. Relief for California’s aquatic ecosystems is essentially on hold.

Disappointingly, the San Francisco Public Utilities Commission (SFPUC) has been one of the staunchest opponents of the Bay Delta Plan. Despite the strong environmental values of their customers, they have refused to accept the critical role instream flows play in ecosystem viability. At the crux of their opposition is a fear that they might not be able to manage their Design Drought – an 8.5-year fictional drought that arbitrarily combines two of the worst droughts from the last century. Interestingly, analysis of historic tree-ring data has revealed that the 1987-92 drought was the driest six-year period over the past 1,100 years, and the 1976/77 drought was the second driest two-year period during that timeframe.

Adding to their extremely conservative planning scenario, the SFPUC assumes water demand will increase to 265 million gallons per day (mgd), despite evidence to the contrary. Demand last year was just 192 mgd – 28% below their assumption – and the SFPUC’s 10-Year Financial Plan forecasts demand will continue to decrease over the coming decade.

To provide near-term relief for the Tuolumne, TRT recently introduced an interim proposal that would enhance instream flows without threatening the SFPUC’s water supply. Using a water supply calculator we created, we demonstrated that the SFPUC could voluntarily contribute their share of the 40% of unimpaired flow adopted by the State Water Board for at least two years, and if those years are dry, followed by a third dry year, the SFPUC could revert back to current baseflows and make it through their Design Drought.

We’re gaining traction on our proposal, and could always use more public support. If you’re interested in getting involved, please email