Models that forecast water that isn’t there hurt all beneficial uses

Assemblymember Adam Gray has called for an audit of the Department of Water Resources and the State Water Resources Control Board, in part to answer the question, What happened in the Water Year 2021 (October 1, 2020 to September 30, 2021) to lead the state to miscalculate by some 700,000 acre-feet the amount of water … Continue reading Models that forecast water that isn’t there hurt all beneficial uses

Fatal errors in DWR’s runoff forecasting: comments to the State Water Resources Control Board

The State Water Resources Control Board held a workshop today (March 16, 2022) on Sacramento River Temperature Management. Among the topics considered were "hydrologic conditions, including operations, forecasting, and accounting." These were my comments. This is Deirdre Des Jardins with California Water Research. I’m the physicist who sent comments to DWR in 2012 predicting the … Continue reading Fatal errors in DWR’s runoff forecasting: comments to the State Water Resources Control Board

A brief history of the water wars — comments to the Delta ISB

On Thursday March 10, 2022, the Delta Independent Science Board received presentations from Brooke Jacobs of the California Department of Fish and Wildlife on the Incidental Take Permit, and from Cathy Marcinkevage of the National Marine Fisheries Service and Kaylee Allen of the United States Fish and Wildlife Service on the Biological Opinions on the … Continue reading A brief history of the water wars — comments to the Delta ISB

Dear DWR, in runoff forecasting, stationarity is dead

For decades, the California Department of Water Resources (DWR) has relied on runoff forecasts from the California Cooperative Snow Surveys (Bulletin 120) for planning State Water Project operations in the late winter and early spring. In 2021, the Bulletin 120 runoff forecasts, which were based on the last 50 years of historic runoff data, were … Continue reading Dear DWR, in runoff forecasting, stationarity is dead

Will State Water Contractors support disclosure of forecast SWP operations?

On January 22, 2022, Dan Bacher published an article, Why is California’s DWR increasing State Water Project allocations in the middle of a drought?  Jennifer Pierre, the General Manager for the State Water Contractors: tweeted the following response to the article: All of the allocated water is already in storage downstream of the Delta. It … Continue reading Will State Water Contractors support disclosure of forecast SWP operations?

In increasing State Water Project allocations, DWR is taking huge risks

The Department of Water Resources has just announced that they are increasing the State Water Project allocations to 15%. Given the huge problems last year with watershed runoff forecasts, DWR is taking a huge risk of not meeting environmental water needs later in the year. In November 2021, nine scientists from leading California water research … Continue reading In increasing State Water Project allocations, DWR is taking huge risks

DWR 2006 study: “too much risk” taken with reservoir operations

In 2006, for the first California Climate Assessment, DWR published a study of operations of the State Water Project and Central Valley Project with climate change. The report was titled, "Progress on Incorporating Climate Change Into Management of California’s Water Resources." DWR's 2006 modeling predicted the current crisis, with Shasta, Folsom, and Oroville reservoirs being … Continue reading DWR 2006 study: “too much risk” taken with reservoir operations

On DWR’s water supply models and drought risks

The Delta Independent Science Board has just released their draft Water Supply Reliability Review. We strongly agree with their recommendation on water supply system models: The next generation of state-sponsored water supply system models for reliability estimation should be built, updated, and evaluated by a broad consortium of state and federal agencies and external experts … Continue reading On DWR’s water supply models and drought risks

Uncertainty in future demand as Urban Water Management Plans finalized

Uncertainty

Population growth in California has changed dramatically due to COVID and a reduction in immigration. The state’s population declined by 182,083 people in 2020, the first time since 1900.  This has resulted in large uncertainty in population projections by the Department of Finance (DOF), which are used by urban water agencies for demand projections for … Continue reading Uncertainty in future demand as Urban Water Management Plans finalized

State Water Contractors objected to development of a drought operations strategy for the State Water Project and Central Valley Project

Lake Oroville March 2021

Our May 10, 2021 blog post, DWR Chief Engineer warned of climate change draining Northern California reservoirs explained how Francis Chung, the Department of Water Resources’ Bay-Delta modeling chief, sounded the alarm in 2010 that climate change could drain major Northern California reservoirs. Chung recommended that DWR develop a reoperation strategy for the State Water Project … Continue reading State Water Contractors objected to development of a drought operations strategy for the State Water Project and Central Valley Project