by Jay Lund
Happy New Water Year! October 1, 2021 is the beginning of the 2022 water year in California, the traditional beginning of California’s “wet season”, such as it will be.
Although there are many fine and interesting stories from California’s current drought, so far, a few stories seem more important and worth summarizing (even though many have been widely covered).
- This is a major drought. The 2020 water year was the 9-th driest year of record and this last year has been the 3rd driest, in terms of precipitation. Warmer temperatures in recent years have further reduced streamflow as more precipitation has evaporated back to the atmosphere before it could flow to streams or groundwater and further stressed ecosystems. Although this is a major drought, in most regards it is not the worst drought California has ever seen, or will see.
- Most people and economic activity in California have been well-insulated from the drought. Urban users have conserved little because they have not been convinced by their local utilities and governments that it is needed, and substantial conservation remains baked in from previous droughts, though much more is possible. Indeed, from a short-term perspective, few urban areas have needed to conserve more. Urban water management, responsible for about 20% of all human water use in California, has done quite well overall, so far. There are, and will be, sizable economic damages from this drought, particularly in some local areas, but statewide, relative to California’s $2+ trillion/year economy, the drought is not a major economic event. Overall, California can afford to focus on addressing particular drought weaknesses.
- Ecosystems are being hammered, especially salmon and forests. This year’s winter-run salmon, already an endangered species, is essentially lost due to too-warm releases and low water levels in Shasta reservoir. Other salmon runs are also suffering from low flows and warm temperatures. Low reservoir levels will make it more difficult to avoid repeating these problems from reservoir operation next year. Forest ecosystems are very dry, with longer and more severe fire seasons and likely many deaths of young and mature trees. Many of these effects will be greatest after the drought in precipitation “ends.” (Moyle and Rypel)
- Agriculture is suffering, but mostly without catastrophe so far, because of increased groundwater pumping. Groundwater withdrawals are most of the statewide agricultural response to drought. Surface water storage has been helpful, but has far less storage capacity and is quite expensive to expand. California’s agricultural prosperity during drought relies primarily on sustainable groundwater storage. (Medellín-Azuara)
- Rural drinking water wells are impacted by increased agricultural pumping. Agricultural pumping lowers water tables and often strands shallower domestic and community wells in rural areas, affecting hundreds to thousands of rural wells. Deeper agricultural pumping is also likely to accelerate the contamination of wells from nitrate in shallower groundwater. Many of those depending on shallow rural wells rely on agricultural jobs. Implementing the Sustainable Groundwater Management Act will help reduce rural drinking water well vulnerability to drought, but this hasn’t happened much yet. (Gailey)
- Increased groundwater pumping increases challenges and urgency of implementing SGMA. Under the Sustainable Groundwater Management Act, all the additional groundwater pumped during this drought must be replenished from reduced pumping and additional recharge before 2040. Faced with droughts and climate change, groundwater plans will need to be made, implemented, and enforced with more spunk than most people have previously thought. This immense challenge will require major painful long-term reductions in irrigated acreage in parts of the San Joaquin Valley. (Escriva-Bou et al)
- Higher temperatures are making seasonal runoff forecasts less reliable, with past forecast methods being too optimistic. Snowmelt in 2021 was about 800 taf less than predicted, based on past relationships between snowpack and runoff. This would be about a 10% over-prediction between runoff predicted and actual annual runoff – valuable water in a dry year. (Abatzoglou et al.)
- An additional dry year could make this drought a whopper. Reservoir levels are everywhere nearing of exceeding new low levels, watersheds are parched, and groundwater tables are dropping. So fewer water reserves would be available for a third dry year, and much more precipitation than usual will be needed for next year to not be dry. One DWR official was recently reported as saying the coming year would have to be at 140% of average precipitation to achieve average annual runoff. Historically, 140% of average precipitation is exceeded in only 27% of years. Overall, we seem likely to see an additional dry year, in terms of runoff. (There is little year-to-year correlation of precipitation in California from year to year, and in northern California, essentially no correlation with El Nino.)
- Many urban areas are preparing for an additional dry year by implementing new water rate structures which would encourage more drought and permanent water conservation while keeping urban water utilities financially solvent. This seems like a good time for water users of all sorts to prepare for an additional dry year and future droughts. Droughts are much less damaging with preparation.
- Long-term preparation gaps. With the climate changing, and many areas having seen benefits from outstanding drought preparation, it is surprising that some areas still lack in preparing for droughts. Drought plans for ecosystems and Delta management seem particularly needed. These gaps reflect the greater difficulty and complexity of these problems and perhaps the lack of political will, evolved consensus, and effective organization to manage these problems. Another year of drought might be needed to spur greater preparation.
These are challenging times for water in California, again.
Abatzoglou, J. et al. “California’s Missing Forecast Flows in Spring 2021 – Challenges for seasonal flow forecasting,” CaliforniaWaterBlog.com, Posted on July 18, 2021
Escriva-Bou, A., et al. “How reliable are Groundwater Sustainability Plans?”, CaliforniaWaterBlog.com, Posted on May 10, 2020
Gailey, R. and J. Lund. “Mitigating Domestic Well Failure for SGMA and Drought in the San Joaquin Valley”, CaliforniaWaterBlog.com, Posted on June 20, 2021
Lund, J. “2021 Drought in California – in one page”, CaliforniaWaterBlog.com, Posted on August 22, 2021
Medellín-Azuara, J. and Jay Lund, J. Jobs and Irrigation during Drought in California, CaliforniaWaterBlog.com, Posted on June 6, 2021
Moyle, P. and A. Rypel. “Drought Makes Conditions Worse for California’s Declining Native Fishes,” CaliforniaWaterBlog.com, Posted on June 27, 2021
Hopefully we’ll see some storms soon.
The 140% percent precipitation to get 100% runoff is a curious estimate. I assume it’s based on how dry the ground is and has nothing to do with filling reservoirs (assuming the DWR estimate is unimpaired).
Also curious about the quote that agricultural prosperity in drought depends on sustainable storage. Long term, that’s true I would think. But short term, should we say unsustainable?
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