While much of the country is buried in snow, California remains sunny and dry, with summer-like temperatures across much of the region. So are we in a drought? Why is it so dry? Has this happened before?
We’ve got answers.
WHERE ARE WE NOW?
Our current rain season started October 1. Since then we have picked up 0.12” of rain. This is only 2% of normal.
WHY IS IT SO DRY?
The La Niña pattern is partially to blame for this. There has been a strong blocking ridge of high pressure that has kept the jet stream pointed at the Pacific Northwest. Seattle currently sits above average with rainfall. Last season’s La Niña had the ridge in a different spot, so we were able to benefit from a more favorable jet stream position.
WHAT IS THE FORECAST?
It is unlikely that we will reach our average rainfall of 14.93” for the season. There’s always a chance for a blockbuster January-March, but keep in mind that October to December accounts for 27% of the total rainfall in an average season. January-March accounts for 63% of the rain in an average year. Yes, on average 90% of our rain falls during a 6-month period.
What does that mean? Let’s say we get average rainfall for every month left in the season…we would only end up at 11.02” of rain.
HAS THIS HAPPENED BEFORE?
We have had a dry start (less than 0.20” for Oct – Dec) 5 times before, the most recent being in 1990. The last time we had 0.12” or less was in 1962. In all 5 seasons, we ended up below average by the end of the season. Some good news though: in 4 of the seasons, we had at least 1 month with normal rainfall or better. In other words: it will rain again.
WHAT’S THE STATUS OF OUR RESERVOIRS?
This part is hard to describe right now. We rely on the State Water Project that uses Lake Oroville as the main source. Right now Oroville is at a lower level due to spillway repairs and construction. I am not sure what this means for SoCal, but I’m sure the Department of Water Resources has a plan to use other reservoirs like Shasta and Folsom. Shasta is at 114% of average for this time of year, Folsom is currently at 119%.
ARE WE IN A DROUGHT AGAIN?
It is too early to say. First we need to see where the rest of the season takes us. While unlikely, there is always a chance that we could recover with a very wet Janunary to March.
An important reminder though: drought is not only based on SoCal rainfall. Northern California has the majority of reservoirs and the bulk of the snowpack. While we have been exceptionally dry, places like Sacramento have at least seen some rain. Right now Sacramento rainfall is at 43% of normal.
One more important factor is the snowpack. Currently the Sierra Snowpack is at 28% of average. While rainfall can temporarily help reservoir levels, it’s the gradual melting of the snowpack that feeds all the streams into the reservoir system. There is plenty of time left to build up some snow in the mountains.
California goes through dry periods (usually 2-3 years long) bookended by 1 or 2 wet years. It is possible we are moving into a dry period.
WHAT DOES THIS MEAN FOR FIRE DANGER?
Our recent fire activity can be blamed on 2 things: the current dry stretch, and the above average rainfall from last season. The wet season triggered plenty of new growth, but now much of that has dried out and turned into fuel. A similar pattern appeared in 2011 and 2012 with an increase in total acres burned by wildfires. This followed the very wet 2010-11 rain season.
6 of the 8 largest Southern California fires happened within 2 years of an above average rain season.
Another 27 million trees died in California last year due to the lingering effects of drought, according to new aerial survey data from the U.S. Forest Service. That brings the total number of trees killed statewide to a staggering 129 million since 2010.
In a typical year, about one million trees die across California. But beginning in 2014, that number began ticking up as aerial surveyors with the U.S. Forest Service started to notice entire hillsides turning yellow, brown and orange. At the height of the drought, in 2016, they counted 62 million dead trees in a single year (here is a map of the mortality progression).
Adrian Das, a forest ecologist with the U.S. Geological Survey, previously told KPCC that he wasn’t surprised that after a single wet winter, trees were still dying.
“The trees have been weakened and under a lot of stress and we have these beetle populations that are doing well,” he said.
Drought often kills trees indirectly. By depriving them of water, trees become weakened and unable to ward off diseases, fungus or bark beetles, which are always present in the forest but explode in numbers when trees are unable to fight them off.
Last winter, more rain and snow fell on parts of the Sierra Nevada than in the previous four years combined. Some trees have recovered, and the death rate is slowing down.
The lower rate could also be a result that so many trees have already died, so there’s just not much left to be killed, said Stephanie Gomes with the U.S. Forest Service’s tree mortality task force.
Indeed, this year’s data shows species with lower death rates in the past are dying in different parts of the state. Previously, the hardest-hit species and regions of California were pines at lower elevations in the Southern Sierra Nevada, where the highest temperatures sucked water out of soil, depriving trees of what little moisture existed. Now, Gomes said death rates are increasingly in higher elevations among fir trees in northern reaches of the mountains.
Part of the problem, scientists say, is that forests throughout the West have too many trees. Historically, many forests used to experience fire more frequently than they do now, which resulted in saplings and small trees dying in the blazes and leaving many forests more open. In the past century, firefighters put out those fires, meaning more small trees were able to survive and forests became crowded.
Now, climate change is forcing more trees to compete for a dwindling amount of water. As temperatures rise due to increasing greenhouse gas emissions,more water gets sucked back into the sky and out of the soil and the ground.
Gomes said the U.S. Forest Service is trying to compensate by thinning out forests either through logging or with prescribed fires so trees don’t have as much competition for water. The agency will also be prioritizing removing dead trees that may pose a safety risk, such as those growing along highways, campgrounds, and power lines. But it is difficult for the agency to do this work when more than half its budget every year goes to fighting wildfires.
“As fire suppression costs continue to grow as a percentage of the Forest Service’s budget, funding is shrinking for non-fire programs that protect watersheds and restore forests, making them more resilient to wildfire and drought,” Randy Moore, Regional Forester of the U.S. Forest Service, Pacific Southwest Region, wrote in the news release.
The autumnal equinox is behind us, and winter looms. Time to do some clean up in the Bay Area garden, get the winter planting done, and get ready to ease into the slow lane. Commercial or Residential
- Although we sometimes have downright hot days, the overall evaporation rate is slowing as the days grow shorter and the nights cooler. That means you can start reducing your irrigation schedule or, depending on what you’re growing, cut it off completely.
- If we don’t have any rain in the next few weeks, water your trees and shrubs to a depth of about 12 inches, once this month.
- You probably don’t need any more incentive after watching the destruction of Wine Country, but you really need to do some fire protection around your home. Prune low-lying branches on shrubs, and clean the eaves to remove leaf buildup. If you have flammable plants close to your home, you might want to get rid of them.
- Shred pine needles, and use them as mulch beneath irrigated, acid-loving plants, or compost them. Trim away dead woody plant parts, and while using oak and redwood leaves beneath those trees as mulch is a good idea, you’ll need to shred them first if you live in a high fire danger zone.
- Plant spring bulbs — daffodils, hyacinths, grape hyacinths — this month and next. Chill tulips before planting.
- This is the week to plant garlic and shallots for harvest next summer.
- Remember, Cleary Bros is your commercial landscaper serving the Bay Area
- If you aren’t growing winter crops this year, considering planting a cover crop to protect your beds and improve their fertility. Plant legumes or grains, or a combination of both.
Santa Clara County’s groundwater — which provides nearly half the drinking water every year for 2 million Silicon Valley residents — fell by up to 60 feet during the state’s recent historic drought due to heavy pumping.
But now the vast underground basins have filled back up to the levels where they were before the drought started in 2011, a welcome trend that experts say was driven by heavy winter rains and strict water conservation rules during the drought that eased the need for pumping.
Monitoring wells run by the Santa Clara Valley Water District first picked up the recovery. And now a new scientific paper published Monday further verifies it.
“People did an amazing job at conserving water during the drought. The entire aquifer recovered,” said Estelle Chaussard, an assistant professor of geology at the University of Buffalo who led the study.
Chaussard analyzed data from four Italian satellites, which measured tiny changes in the surface levels of the ground in Santa Clara County during California’s five-year drought. She found that as groundwater levels plummeted during 2013 and 2014, the ground itself fell as the amount of water underneath it was depleted, a phenomenon known as subsidence. From 2011 to the summer of 2014, for example, an area just north of Happy Hollow Zoo near downtown San Jose saw a 2-inch drop in the ground level, as the ground dried out like a sponge sitting in the sun.
Monitoring wells in the same area showed that the groundwater table fell by at least 60 feet during that time. Similar drops occurred in the Campbell and San Martin areas, and drops of 12 to 19 feet happened in the water table under Sunnyvale and South San Jose’s Coyote Valley.
But when Gov. Jerry Brown and the Santa Clara Valley Water District moved from voluntary to mandatory conservation measures, the district limited yard watering, boosted rebates for water-efficient appliances, and hired “water cops” to leave door hangers and send letters to people watering wastefully during the hot part of the day. And significantly less water was pumped from the aquifers, which are sand and clay formations saturated with water.
At the same time, the water district continued to recharge the aquifers with some water it had in local reservoirs by moving it into dozens of percolation ponds spread throughout the county. It also used water imported from other places, such as the Semitropic Water District, where it stores groundwater near Bakersfield, to keep recharging the ground like a homeowner putting money back into the bank every month during an economic downturn.
“We were working on all fronts to reduce pumping,” said Vanessa De La Piedra, groundwater management unit manager for the Santa Clara Valley Water District. “We saw the very positive results of that. Groundwater levels started to recover in 2015 even though we were still in the drought.”
The ground level began to slowly rebound in 2015, Chaussard’s research showed, as more water underground essentially pushed it back into place. In 2015, Santa Clara County residents reduced water use 27 percent overall from 2013 levels.
When El Niño storms finally brought normal rainfall to Northern California in the winter of 2015-16, Santa Clara County’s aquifers continued to recover. And by 2017, when the wettest winter in 20 years caused downpours and floods, they were back to pre-drought levels, the district’s wells showed.
The study was published in the Journal of Geophysical Research, and also includes researchers from NASA’s Jet Propulsion Laboratory in Pasadena, UC Berkeley and Purdue University.
It helps demonstrate that satellite technology can be a useful tool in enabling communities to track the health of their groundwater basins, said Jay Famiglietti, a senior water scientist at NASA’s Jet Propulsion Laboratory, and a professor of earth system science at the University of California, Irvine.
But the good news in Santa Clara County isn’t being replicated in other parts of the state, he said. Of particular concern is the San Joaquin Valley, where farmers for years have overpumped groundwater with little or no recharging efforts, increasing pumping costs and causing roads and concrete canals to buckle and crack as the ground sinks.
“Most of the groundwater that is being pumped in the southern San Joaquin and Tulare Lake basins is much, much deeper,” Famiglietti said. “Those aquifers would take decades to centuries of extremely strict management to recover significantly.”
Santa Clara County has a long history of groundwater struggles. The water table fell nearly 200 feet from 1915 to 1960 as farmers and residents of growing suburbs increased their water use. Subsidence caused the ground to fall as much as 13 feet around San Jose. But when the water district began to construct local reservoirs, import water from the Delta and impose what’s commonly known as “the pump tax” to fund groundwater recharge programs, the water table began to slowly recover.
It is currently back up to basically the same level it was 100 years ago, despite the fact that the county’s population has grown by more than tenfold in the past century from 83,000 in 1910 to 2 million today. Even during the lowest point in the recent drought, the county’s water table was still far higher than it had been in the 1960s and 1970s.
In 2014, in what may be the most important lasting legacy from California’s 2011-2016 drought, state lawmakers passed a sweeping new law aimed at better regulating groundwater in California. Most other Western states, including Texas, were decades ahead of California.That law requires local government agencies in places where groundwater is most at risk to draw up plans to recover it — which could include local agencies levying fees and taxes on farmers and other users to pay for groundwater recharge projects, and potentially, for limits to be placed on how much groundwater can be removed in any year.
Critics, including some environmental groups, said that the law takes too long to take effect. As part of a compromise with farmers, it gives areas until 2040 to bring their groundwater pumping back to sustainable levels.
Good habits die hard, it seems, after five years of epic drought – for most Californians, anyway.
The historic dry spell from 2012 to 2016 prompted many state residents to reduce their water consumption, as did strict regulations imposed by state agencies and individual water districts. Whether they wanted to or not, urban Californians reduced their use of the state’s most precious resource by about a quarter.
Now, after mandatory conservation targets were lifted in April following a very wet winter, many Californians continue using less water than they were prior to the drought. In Sacramento, Los Angeles, most of the San Francisco Bay Area and Orange County, urban residential water use is down between 20 and 26 percent since 2013, often used by water agencies as the benchmark year for pre-drought water consumption, according to the State Water Resources Control Board.
That said, water conservation is already slacking off a bit – and more in some areas than in others. In the summer of 2015 – the height of the drought – Californians’ savings on water use peaked at about 25 percent of 2013 levels. A report from the State Water Resources Control Board shows statewide savings on urban water use for June 2017 totaled 17 percent. In other words, though we’re still using less water than we were in 2013, our consumption is rebounding.
Heather Cooley, the water program director for nonprofit Pacific Institute, says such a post-drought uptick in water use is to be expected.
“We see this looking back at other droughts, like in the late 1980s and early 90s,” she said. “People cut their water use, and then it rebounds a little, though never to pre-drought levels.”
Andrea Pook, a spokeswoman for the East Bay Municipal Utility District, says she expects the rebound in post-drought water use to be slight, at most. That is because people are better educated now in water use efficiency than they were just a few years ago, she said in an email. Not only that, many Californians installed more efficient appliances during the drought and replaced water-hogging lawns with drought-tolerant California native plants – actions that should translate into permanent savings.
Sage advice from our friends at Contra Costa Water District.
As we approach summer, it’s clear our water supply is in a good position. The state-declared drought that began in 2014 is officially behind us, but we still should be mindful of efficient use of our water.
You can give your yard the water it needs, but we ask that you do so wisely. It is possible to have beautiful lawns and gardens without wasting water. Please remember the common sense water rules from the drought and make them habits: Adjust sprinklers to avoid runoff, fix breaks and leaks in your sprinkler system and turn off sprinklers during and after rains. Please use our outdoor watering schedule to help you accurately set sprinkler timers to your yard’s needs each month.