Dollars and drops per California crop

Aerial view of rice fields near Sacramento, California. Photo by Paul Harnes/California Department of Water Resources

Rice fields near Sacramento in 2009. Photo by Paul Harnes/California Department of Water Resources

By Josué Medellín-Azuara and Jay Lund

When it comes to water, California’s irrigated agriculture is always under the public magnifying glass because it is the largest managed water use in the state and the economic base for many rural areas. During a prolonged drought like the current one, however, crop water comes under a microscope.

We have compiled a table to help answer questions on which crops use the most water and which crops provide the most economic “pop per drop.”

The estimates are very broad because California is so diverse in crop varieties, agricultural practices and local water availability. But the numbers are still useful for comparison purposes.

Note that the amount of water applied to a crop – “gross use” – is not the same as its “net use,” as some of that water seeps underground and replenishes aquifers or is reused downstream.


Some observations about the data:

  • The “truck (vegetables) and horticulture (garden plants)” crop group has the highest revenue per net water use, followed by the “fruits and nuts” group. Together, these two large crop categories account for nearly 86 percent of all crop revenue, but occupy only 47 percent of the irrigated cropland and use just 38 percent of the water applied to that land.
  • Fruits and nuts are grown on about one-third of the irrigated cropland and use one-third of the water, but produce nearly 45 percent of the total crop revenue.
  • Alfalfa, corn irrigated pasture and other livestock fodder account for nearly 37 percent of all net water crop use, but produce less than 7 percent of total crop revenue. However, the ranches and dairies that depend on these foodstuffs generate more than 22 percent of California’s agricultural production value, which totaled $45 billion in 2012.
  • Rice fields use a lot of water but also provide important bird habitat.

Josué Medellín-Azuara is a senior researcher and Jay Lund is a professor of civil and environmental engineering with the UC Davis Center for Watershed Sciences.

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Making every drop count in drought – and deluge

A swollen Cosumnes River in wet years and can help recharge local aquifers, providing much needed drinking water and irrigation supplies during droughts. UC Davis

A swollen Cosumnes River earlier this year helped recharge aquifers in the Lodi area, providing much-needed drinking water and irrigation supplies during the drought. Photo: UC Merced

By Joshua Viers and Graham Fogg

A little publicized but highly curious part of the emergency drought legislation signed by Gov. Jerry Brown last month advances hundreds of millions of dollars to shore up and replace aging levees in flood prone areas of the state.

Drought relief through better flood control? Really?

As it turns out, some flood protection projects are important during droughts. Strategically removing sections of old levees or rebuilding them hundreds or thousands of feet from their original riverbank sites can significantly replenish aquifers during wet years, providing badly needed supplies during droughts.

The drought relief package accelerates the appropriation of $660 million from a 2006 flood protection bond act (Proposition 1E) that specifically authorizes construction of such “setback levees” because of the groundwater recharge value and other benefits they provide.

Setback levees are not new. The Dutch have them to improve flood control; allowing floodwaters to spill onto undeveloped or farmed floodplains lowers the flood risk for communities downstream. Their use in California, however, has been much more limited. Local flood control and reclamation districts have focused more on keeping century-old levees intact (Suddeth, 2010).

Some agencies are beginning to rethink this approach as growing numbers of studies point to the multiple economic and environmental benefits of reconnecting rivers with their walled-off floodplains.

It’s easy to forget the Central Valley was once a vast wetland (Whipple et al, 2012). Before we built dams and straightjacketed rivers with levees and riprap, floodwaters would swell onto floodplains (Mount, 1995). The water would percolate into the ground and refill local aquifers. Inundated floodplains also served as nurseries for fish, with abundant insect food and ideal water temperatures for growing bigger and faster – improving their odds of survival in the ocean (Jeffres et al, 2008).

Today, with only 5 percent of the floodplains left undeveloped, California affords few opportunities for floodwaters to restock local aquifers (Hanak et al, 2011). The levees built in the late 1800s and early 1900s to hold back floodwaters from cities and farms now stand as barriers to residents and farmers needing to expand groundwater supplies for drinking water and irrigation.

Three years ago our team of watershed scientists set up an experiment on the Cosumnes River Preserve near Lodi to better understand the relationship of river levees to groundwater recharge. The Nature Conservancy removed about 750 feet of old riverside levee and breached additional levees to increase access of floodwaters onto the floodplain. Scientists monitored the biophysical response.

Researchers found that moving levees on the Cosumnes River can help recharge groundwater. From left, scientists on the project include Drew Nichols from UC Davis, Christina Bradley from UC Merced, Carson Jeffres of UC Davis and Marilyn Fogel of UC Merced.

Researchers found that removing a section of old levees on the Cosumnes River Preserve appreciably restocked local aquifers. From left, scientists on the project include Drew Nichols of UC Davis; Christina Bradley, UC Merced; Carson Jeffres, UC Davis; and Marilyn Fogel, UC Merced. Photo: UC Merced

Preliminary results have been encouraging. Removing the levee on the Nature Conservancy’s 500-acre experimental floodplain appreciably replenished local aquifers and reduced flood risks for area landowners. Just a brief storm in early February added roughly 100 to 300 acre-feet of water to local groundwater stores.

Now that this floodplain will become inundated more frequently, the recharge will continue to grow with each year, possibly resulting in about three times more recharge than would occur from irrigation. The annual amount of net groundwater recharge might amount to 1,000 acre-feet, or more – not bad for such a small area.

Building setback levees is expensive. A 3,400-foot-long structure and associated riparian restoration planned along the lower Feather River in Sutter County is estimated at $20 million. But in reconnecting rivers to their floodplains, these projects can yield the multiple long-term benefits of reduced flood risk, increased groundwater recharge and improved wildlife habitat.

Some communities in the Sacramento-San Joaquin Delta may find this room-for-rivers approach particularly beneficial. It may be more economical to reduce flood risk by expanding floodplains rather than shore up aging levees to meet the new 200-year flood protection requirement. The approach also may be attractive to some communities in the San Joaquin Valley where groundwater overdraft is most pronounced.

The best time to prepare for floods is before they happen. Making every drop count during a deluge can pay dividends when droughts recur and wells start to dry up.

Joshua Viers and Graham Fogg are scientists with the University of California’s Water Security and Sustainability Research Initiative. The groundwater recharge experiment on the Cosumnes River Preserve is conducted in cooperation with the California Department of Fish and Wildlife, Point Blue Conservation Science and the Nature Conservancy.

Further reading

Cosumnes Research Group projects, UC Davis Center for Watershed Sciences

Dutch “Room for the River” program 

Fleckenstein, J., M. Anderson, G. Fogg, and J. Mount. 2004. “Managing surface water-groundwater to restore fall flows in the Cosumnes River.Journal of Water Resources Planning and Management 130, pp. 301-31

Hanak E, Lund J, Dinar A, Gray B, Howitt R, Mount JF, Moyle P, Thompson B. 2011. Managing California’s Water: From Conflict to Reconciliation. Public Policy Institute of California

Jeffres, C., J. Opperman and P. Moyle. 2008. “Ephemeral floodplain habitats provide best growth conditions for juvenile Chinook salmon in a California river.” Environmental Biology of Fishes 83 (4): 449-458

Mount, J. and Twiss, R. 2005. “Subsidence, sea level rise, and seismicity in the Sacramento-San Joaquin DeltaSan Francisco Estuary and Watershed Science, 3(1)

Mount, J. 1995. California Rivers and Streams: The Conflict between Fluvial Process and Land Use. University of California Press. Berkeley, Calif.

Suddeth, R., J. Mount, and J. Lund. 2010. “Levee Decisions and Sustainability for the Sacramento-San Joaquin Delta.” San Francisco Estuary and Watershed Science 8 (1)

Time lapse video of flooding on Cosumnes River, winter 2014-2015, UC Davis Center for Watershed Sciences

University of California Water Security and Sustainability Research Initiative

Whipple AA, Grossinger RM, Rankin D, Stanford B, Askevold RA . 2012. Sacramento-San Joaquin Delta Historical Ecology Investigation: Exploring Pattern and Process. Publication #672, San Francisco Estuary Institute-Aquatic Science Center, Richmond, Calif.


Integrated Environmental Modeling
Ocean, estuarine and watershed systems
May 21-22, 2015
UC Davis

Please join us for this international workshop on advancing environmental modeling. 

We are bringing together experts from Europe, Asia and across the U.S. to explore ways to improve the development, application and integration of modeling for multipurpose management of ocean, estuarine and watershed systems.

Community-based modeling, public domain platforms and integrated modeling from various systems will be discussed. A white paper developed from workshop proceedings will be prepared and released to improve modeling integration. 

Admission is free, but please register in advance:  


Further information: integrated

Organizers: Peter Goodwin and Chris Enright, Delta Stewardship Council/Delta Science Program; Josué Medellín-Azuara and Jay Lund, UC Davis Center for Watershed Sciences; Benjamin Bray, California Water and Environmental Modeling Forum

Sponsors: National Science Foundation in partnership with the California Water and Environmental Modeling Forum and the International Association for Hydro-Environment Engineering and Research


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Exotic animals deployed as Delta ‘weed whackers’


Coast guard crews keep close watch on the pod of hippos grazing in and around the weed-infested Stockton Deep Water Ship Channel. Photo courtesy of U.S. Coast Guard

By Nestle J. Frobish

Visitors to the Sacramento-San Joaquin Delta are doing double takes lately as they encounter some newly introduced “biological controls” to keep a fast-spreading waterweed from damaging boat propellers and choking off waterways.

Working with state water officials, UC Davis scientists last month released a herd or “bloat” of hippopotamuses from Botswana to chow down on vast mats of water hyacinth that also threaten to clog the intake to the California Aqueduct near Stockton.


Water hyacinth in Delta. 

Elsewhere in the Delta, the researchers also planted hyacinth-loving manatees imported from Florida and giant guinea pig-like rodents from Brazil called capybaras.

The menagerie of radio-tagged herbivores is part of a yearlong experiment in more natural and, some say, more effective, controls for curbing the menacing growth of non-native aquatic weeds in the Delta.

Source: Wikicommons

A hippopotamus pokes its head out of the hyacinth-covered Clifton Forebay in the Delta. Source

Enlisting hippos in the biowarfare is the brainchild of Robert Broussard, a professor with the UC Davis Center for Watershed Sciences who has long touted biological controls as a cost-effective way to keep the growth of hyacinth in check.

“What better way to fight an alien species than by introducing still more alien species?” Broussard said.

State and local agencies have poured millions of dollars into chemically and mechanically clearing Delta waterways of the hyacinth, a floating ornamental plant, and the submerged Brazilian Waterweed. But this year the combination of severe drought and slower-flowing, nutrient-laden water has created a perfect storm for waterweed growth. There is no known way to eradicate the weeds.

Source: California Department of Water Resources

In 2014, the state treated 2,617 acres of water hyacinth in the Delta with the herbicides glyphosate and 2,4-D. Source: California Department of Water Resources

In some areas the invasive plants have grown so dense that they have threatened not only boat safety and the Delta’s ecological balance but also cargo ship traffic and the state’s water supply.

“Hippos were the furthest things from our minds when we asked UC Davis to find alternative solutions,” said Terry Drinkwater, spokesman for the California Department of Water Resources. “But, I must admit, when it comes to water hyacinth, these river horses are as hungry as, well, horses.”

In their native African habitat, hippos mainly eat aquatic plants, including hyacinth, which they devour at a rate of 200 to 300 pounds a day. The mammal’s affinity for the plant inspired the character “Hyacinth Hippo,” the prima ballerina from the “Dance of the Hours” sequence of Disney’s Fantasia. 


Brazilian waterweed. Photo: California State Parks

“We believe the rate of consumption will be even higher in the Delta with Brazilian waterweed spicing up the mix,” said Broussard, adding that he routinely blends the weed into his own diet of mainly Cajun cuisine.

Officials are taking special measures to keep onlookers at bay because hippos are highly territorial and would likely attack people who encroach on their turf.


Students of UC Davis professor Peter Moyle (background) pose with a manatee last week before releasing the mammal into Delta waters. Photo by Bo Manfree/UC Davis

The Coast Guard has volunteered a crew to shepherd the bloat of hippos currently grazing in the Clifton Court Forebay, a reservoir that serves as the intake for California Aqueduct diversions to Southern California. Working from jet skis, the crew has been herding the hippos between the forebay and the Stockton Deep Water Ship Channel, where boating and shipping has been stymied by floating mats of hyacinth.

Coast Guard Lieutenant Commander Quinton McHale called the effort in the Delta a “war on weed” and said the public safety interest is no different from law enforcement’s effort to combat marijuana growing along California’s north coast.

“You might as well call the Delta the ‘Emerald Triangle,’” McHale said in a recent interview aboard his patrol board, PT-73.

Stockton Mayor Anthony Silva said he plans to promote the hippos as another tourist attraction for the destination city.

UC Davis water science student coax a capybara into the waters at the Delta Yacht Club of the San Joaquin River. The marina is infested with water hyacinth. The rodent is known to devour up to 40 pounds of the invasive weed a day. Photo by Bo Manfree/UC Davis

“I’m just trying to think of everything,” Silva said. “You just know darn well there’s got to be a way we can make money off those big bad boys. Hippos in Stockton is a wacky idea, so we’re calling them ‘Weed Whackers’. Get it?”

Researchers will be comparing the hippos with the more gentle manatees and the web-footed capybaras on feasibility, cost and effectiveness in the waterweed control experiment.

Follow-up work will include a special genetic breeding program to create more voracious aquatic herbivores. “If this doesn’t work, we will be considering barriers in the Delta to limit the spread of waterweeds,” said Cornelius Biemond, deputy director of water supply at the Department of Water Resources.

Jake Lunge, director of the Center for Watershed Sciences, said that adding these “four-legged locusts” to the state’s arsenal of pesticide spraying boats and mechanical waterweed harvesters will likely boost the state’s water supply during this fourth year of severe drought.

“Grazing these vast mats of hyacinth will reduce evapotranspiration and save a lot of water,” said Lunge, a civil professor of ornamental engineering.

“This could help keep California from running out of water by the end of the year.”

Nestle J. Frobish, former chairman of the Worldwide Fair Play for Frogs Committee, is curator of the UC Davis Center for Watershed Sciences.

Further reading

Andersen, T. “Water hyacinth thrives in drought-stricken Delta.” Bay Nature. Dec. 22, 2014

Breitler, A. “Stockton mayor floats an idea: Bring in manatees.” The Record (Stockton). Nov. 8, 2014

Breitler, A. “Port of Stockton: Vessel stopped by tangled mats of hyacinth,” The Record (Stockton)Oct. 28, 2014

Fitzgerald, M. “Hyacinth? Think giant amphibious hamsters.” The Record (Stockton). Nov. 3, 2013

Hippopotamus Stew.

Jackson, W.T. and Paterson, A.M. (1977), “The Sacramento-San Joaquin Delta – The evolution and implementation of water policy – an historical perspective.” Contribution No. 163. California Water Resources Center, UC Davis

Miller, G. “The crazy, ingenious plan to bring hippopotamus ranching to America.” Wired. Dec. 20, 2013

MSNBC picks up California WaterBlog story on Delta hippos

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The California Drought of 2015: A preview

Dry fields and bare groves looking west toward the Coast Range, near San Joaquin, Calif. Photo by Gregory Urquiaga/UC Davis, 2014

Dry fields and bare groves looking west toward the Coast Range, near San Joaquin, Calif. Photo by Gregory Urquiaga/UC Davis, 2014

By Jay Lund

This fourth year of drought is severe, but not yet the driest ever. The drought’s impacts are worsened by record heat, which has dried out soils and raised the demands for irrigation, and the historical high levels of California’s population, economy, and agricultural production, and historical low levels of native fish species. There is need for concern, preparation and prudence, but little cause for panic, despite some locally urgent conditions.

How dry?

This year will be about as dry as last year. This is bad, as 2014 was the fourth to eighth driest year in 106 years of recordkeeping, by most reasonable reckonings. This year will be a little different overall, but quite different in some areas, both better – Santa Cruz – and worse – eastern San Joaquin Valley.

Statistically, last year’s drought is about a one in 15-30 year event. With a changing climate and growing water demands, we should prepare for such droughts occurring more than once a generation.

As detailed below, Northern California will be critically dry, having about the same precipitation as 2014 (more in some basins), less snowpack and more storage in some of the largest reservoirs.

The southern Central Valley is as dry or drier than 2014, with abysmal precipitation and snowpack. The western side benefits from having more water stored in San Luis Reservoir than in 2014, but the eastern side has less water remaining in its major reservoirs. Southern California is in similar shape as in 2014 for surface water.  Little time is left in California’s “wet” season, and the forecast for the coming week or so is quite dry. What we see is probably what we’ve got.

Water allocations for the State Water Project are small (20 percent), but better than last year’s 5 percent allocation. Federal Central Valley Project allocations are likely to be 75 percent (and perhaps 100 percent) for higher-priority contractors, 25 percent for cities, and zero for everyone else.

Some locally supplied eastern San Joaquin Valley irrigation districts are delivering no more than 30-35 percent of normal supplies; Merced Irrigation District is delivering no surface water.

Junior water-right diversions in the Central Valley will be curtailed. After reservoir withdrawals last year and little refill this year, eastern San Joaquin Valley will be hit much harder this year. Tulare basin water shortages are about like 2014 or worse, and Sacramento Valley shortages are about the same or a bit less.

Almost the entire state has less groundwater because of three previous years of drawdown. More wells are likely to go dry, particularly for rural households and small water systems, but probably also some irrigation wells.

What will we do?

California will not run out of water this year, or next, if we are careful. We will respond mostly as we did last year, with some modest changes.

In rough order of importance, California will make up most of this year’s water shortage by:

  • Additional groundwater withdrawals of perhaps 5 million or more acre-feet
  • Reductions in urban and environmental water uses and agricultural fallowing — totaling perhaps 4 million acre-feet
  • Shifting perhaps 1 millon acre-feet of water use from lower to higher economic values through water markets
  • Depleting reservoir storage by perhaps 1-2 million acre-feet
  • Increasing wastewater reuse and other conservation efforts

Making rain is not an option.

In many places, groundwater will be less available and farther from the surface than last year, with more dry wells and more expensive pumping. Somewhat more surface water will be available in some places, including the North Coast, Santa Cruz, Sacramento Valley and western San Joaquin Valley. Less will be available for eastern San Joaquin Valley. Further reductions in urban water use are likely for  the Bay Area and Southern California.

Drought impacts on fish and wildlife and hydropower should be similar to those in 2014.

California is not running out of water

Economic and environmental factors will dampen many popularly espoused or feared actions, such as widespread ocean desalination, extensive capturing of stormwater, vast reuse of treated wastewater, eliminating exports of water-intensive foods, abandoning major irrigation districts, fog water collection, iceberg towing and importing water from Canada, the Colombia River, the Great Lakes or anywhere else.

Less extreme water management activities should be adequate, less costly and better environmentally, even for much more extreme droughts than today’s. California is not running out of water.


Droughts bring public and political attention needed to make major changes in water management, such as last year’s historic groundwater legislation. Strategic changes usually require serious long-term problems and thinking, and the urgency of a drought or flood to focus policy discussions.

What changes are likely from this year’s drought? It is hard to know now, but here are some promising candidates:

  • Water measurement and accounting. The 2009 drought brought legislation that began improving basic data on surface water use and groundwater levels. Much more is needed to tighten California’s water accounting closer to that of other western states. Improved water-use data is unlikely to require massive new reporting, but rather improved coordination of existing reporting, some new reporting, and perhaps remote sensing estimates of crop water use (as is done in Idaho). Some additional reporting, such as requiring large water users to “call” their use during drought, would improve use of available water and add reliability to both senior and junior water rights. For better accounting to occur, the state needs a common comprehensive and workable regional water accounting system serving both the State Water Resources Control Board and the Department of Water Resources.
  • Groundwater. A dry 2015 seems only likely to accelerate implementation of local and state groundwater sustainability efforts. Perhaps the best outcome would be legislation to speed groundwater basin adjudications and better empower and guide local groundwater sustainability agencies. Consolidating state groundwater data and analysis now scattered across agencies and programs would be another positive outcome.
  • Water markets. More expeditious and transparent trading of water rights and longer-term water rights contract. From a statewide perspective, the amount of water traded would be small, but the economic and environmental benefits would be great. Water markets are also probably the best means to provide flexibility and incentives needed to improve groundwater recharge, coordinate storage operations, appropriately conserve water, and revitalize environmental water management.
  • Reducing net water use. A primary response to water shortage is to reduce water use in ways that conserve the most water with the least economic and environmental cost. This applies to all water-use sectors during droughts and in the longer term. Improving water rate structures and economic incentives with pricing and markets will be important here, even for some environmental water uses.
  • Sacramento-San Joaquin Delta. Water diversions from the Delta are unfortunately central to California’s water system. They will be less during a drought, but what remains becomes quite valuable. The economic value of the diversions will likely increase with climate change and groundwater sustainability, as local areas seek additional external water supplies. After groundwater, the Delta is probably the state’s most strategic water problem. This year’s drought will provide opportunities and motivations for long-term progress on managing the Delta.

Overall, the drought of 2015 will be a challenge. We can complain and suffer with the usual lament over water waste (by others, of course), or we can make inconvenient and sometimes costly changes for the better.

Jay Lund is a professor of civil and environmental engineering and director of the Center for Watershed Sciences at UC Davis. 

Some arid details at the end of March

Precipitation and snowpack

No “Miracle March” this year.  We had appreciable precipitation only in December and February — one sizable storm each month. The other months were almost entirely dry for most of California.

North Coast streams are in better shape, but the Sacramento Valley is only slightly wetter than in 2014. San Joaquin and Tulare basins are about as dry as this time last year, with dry weather forecast for the short remainder of the “wet” season.  2015 could be the driest year of record for the southern Central Valley.

Snowpack is a little worse than last year, perhaps the driest on record statewide.

As of March 29, the Northern Sierra (Sacramento Valley) Precipitation Index was down to 77 percent of average to date, slightly higher than that for all of 2014. Source: Calif. Data Exchange Center. For updates, click here.

As of March 29, the Northern Sierra (Sacramento Valley) Precipitation Index was down to 76 percent of average to date, slightly higher than that for all of 2014. Source: California Data Exchange Center. For updates, click here.

Precipitation is less than half of average for this time of year in the San Joaquin Valley. Snowpack is a little worse than last year, perhaps the driest on record statewide. Source: California Data Exchange Center. For updates, click here.

Tulare basin has a shorter record though it has the most water use in California. Source: California Data Exchange Center. For updates, click here.

Tulare basin has a shorter record though it has the most water use in California. Source: California Data Exchange Center. For updates, click here.

Snowpack is truly sad, about 6 percent of average for this time of year. Source: California Data Exchange Center. For updates, click here

Snowpack is truly sad, about 6 percent of average for this time of year. Source: California Data Exchange Center. For updates, click here


Reservoir storage is better overall than last year. Still, it’s about 6 million acre-feet below average with no prospect for much refill from snowmelt. The big reservoirs in the Sacramento Valley are 1.3 million acre-feet fuller.

Storage south of the Delta is about the same, though distributed differently. San Luis Reservoir, which serves the state and federal water projects, is about 600,000 acre-feet higher than they were a year ago, but the large reservoirs on the San Joaquin River tributaries are about 600,000 acre-feet lower. Exchequer Reservoir is at 9 percent of capacity.

Source: California Data Exchange Center. For updates, click here

Source: California Data Exchange Center. For updates, click here


Groundwater storage is probably about 6 million acre-feet less than this time last year. Aquifer levels will generally be lower than a year ago in the areas highly dependent on groundwater.

Further Reading

For more data of the status of California’s water supply, explore the Department of Water Resources’ California Data Exchange Center

Fimrite, P. “California drought: Sierra Nevada snowpack hits historic low.” San Francisco Chronicle. March 28, 2015

Kasler, D. “California’s hydro power dries up as drought worsens; utility customers paying more.” The Sacramento Bee. March 27, 2015

Lund, J. “Could California weather a mega-drought?California WaterBlog. June 29, 2014

Lund, J. “The California Drought of 2015: March.” California WaterBlog. March 5, 2015

Lund, J. “The California Drought of 2015: February.” California WaterBlog. Feb. 4, 2015

Lund, J. “The California Drought of 2015: January.” California WaterBlog. Jan. 5, 2015

Lund, J. and J. Mount. “Will California’s drought extend into 2015?California WaterBlog. June 15, 2014

Walton, B. “California drought is not lifting.” Circle of Blue. March 30, 2015

Swain, D. “The Ridiculously Resilient Ridge Returns; Typical winter conditions still nowhere to be found in California.” California Weather Blog. Feb. 16, 2015

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Water giveaways during a drought invite conflict

In the summer of 2014, UC Davis researchers recorded the effects of the drought on California streams, including this isolated pool on Hatch Creek near Don Pedro Reservoir. Photo by Andy Bell, UC Davis

In the summer of 2014, UC Davis researchers recorded the drought’s effects on California streams, including this isolated pool on Hatch Creek near Don Pedro Reservoir. Photo by Andy Bell, UC Davis

                                                This article first ran in the San Francisco Chronicle on March 20, 2015.

By Jay Lund and Peter Moyle

When labor is scarce, people move to better jobs with higher wages. When land is scarce, landowners are offered higher prices for its use. When drought makes water scarcer in California, those with senior water rights are offered more money to move their water to other users.

But fish are asked to give up their water for free.

California would do better if it cultivated a more civilized ethic where there is no free water during a drought. Perhaps we should treat environmental uses of water more as a matter of economics, to help the environment and the economy.

This year and last year, the State Water Resources Control Board relaxed environmental protections for fish to export more water from the Sacramento-San Joaquin Delta for farms and cities. Reducing fish flows without compensation during a drought has some attractions, but overall seems like a risky idea.

On the plus side, it’s a principle that, during a drought, everyone should get less water, including the environment. The reality is that some small reductions in environmental flows may not harm fish, but would have great economic value to cities and farms. Variability in flows is natural for many of California’s native ecosystems. Droughts might provide useful variability, if properly managed.

However, reductions in environmental flows during drought usually have costs, including:

Potential direct harm to fish in the short term, and in the longer term, severely reducing native fish populations and sometimes making it easier for invasive species to become established.

Risks that additional native fish or other aquatic species will become legally listed as threatened or endangered, which can reduce long-term water withdrawals for economic water uses.

Encouraging water fights, rather than using negotiation or markets to rebalance and reallocate water. This is uncivilized and encourages greater conflicts over water.

The amount of environmental flows that cities and farms will gain this year is relatively small, about 40,000 acre-feet of water. But in a drought year, 40,000 acre-feet of water south of the delta is probably worth more than $1,000 an acre-foot or about $40 million. While this is a tiny proportion of agricultural production or urban economies, those next in line for this water will find it worth fighting for.

The high value of small amounts of water during droughts is a harsh challenge for science, environmental advocates and those interested in thoughtful water policy. How can we make this a more civilized choice?

Let the fish sell their water.

Peter Moyle reacts to finding some rare Red Hills roach on Horton Creek, a tributary of Six-bit Gulch. The UC Davis professor of fish biology feared the species had gone extinct because of the drought. Photo by Karin Higgins/UC Davis, Aug. 14, 2014

Peter Moyle reacts to finding some rare fish on drought-stricken Horton Creek, near Sonora, in August 2014. He  feared the species — Red Hills roach — had gone extinct because of the drought. Photo by Karin Higgins/UC Davis

That is, convert some drought portion of environmental flows to a marketable water quantity, owned by the fish agencies. This would allow environmental water uses to be fairly compensated by those gaining from reductions in environmental flows, just as other high-priority water rights holders are compensated for their reductions in water use during a drought. This seems more fair, gives incentives to water users to behave better, and encourages conflicts to be speedily negotiated instead of indefinitely litigated. [1]

Prices could be set by the fair market value of the water made available, by having a regulatory agency fix or negotiate a fee, or by assessing the cost of compensatory environmental actions such as buying water for environmental purposes elsewhere in the state or creating a reserve fund to aid native fish after the drought.

Creating such an environmental water market during a drought would help limit the reductions in environmental river flows, while ensuring that those negatively impacted by such reductions receive some compensation.

For California, even partial markets for environmental water would satisfy the state’s stated “co-equal” environmental and economic goals for water management.

Overall, fish have suffered at least as much as humans during the drought, certainly in terms of habitat loss.

We can’t equalize the burdens of severe drought across all water uses, but we can share the pain more fairly in ways that help fish and other species that depend on our rivers for their survival.

Jay Lund is director of the UC Davis Center for Watershed Sciences and a professor of civil and environmental engineering. Peter Moyle, the Center’s associate director, is a professor of fish biology.

[1] Reductions in environmental flows could be compensated through existing legal mechanisms such as negotiated agreements with water users; fixed penalties for violating flow and water quality standards; or Endangered Species Act regulatory actions — adding environmental market provisions to biological opinions, incidental take permits or habitat conservation plans (Lund et al, Feb. 2014).

Further reading

Lund, J. and P. Moyle. “Is shorting fish of water during drought good for water users?” California WaterBlog. June 3, 2014 

Lund, J., E. Hanak, B. Thompson, B. Gray, J. Mount and K. Jessoe (2014), “Why give away fish flows for free during a drought?” California WaterBlog. Feb. 11, 2014

Manfree, A. “Drought Journal: Search for Sierra fish goes from bad to worse.” California WaterBlog. Aug. 18, 2014

Moyle, P. “Saving California’s salmon during a severe drought.” California WaterBlog. Feb. 17, 2014.

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Prepare for extinction of delta smelt

Photo: UC Davis

An adult delta smelt caught in a survey of fish in the Sacramento-San Joaquin Delta. Photo: UC Davis

By Peter Moyle

I saw my first delta smelt in 1972, during my first fall as an assistant professor at UC Davis. I was on a California Department of Fish and Wildlife trawl survey to learn about the fishes of the Sacramento-San Joaquin Delta. The survey then targeted young striped bass, but the trawl towed behind the boat captured large numbers of the native delta smelt.

I remember a single haul with a couple hundred of these iridescent finger-length fish being dumped into a container on deck. I decided to study smelt biology because these fishes were so abundant and yet so poorly studied. I would have no trouble collecting enough of them for my research.

Fall midwater trawl. Photo: California Department of Fish and Wildlife

A mid-water trawl used in fall surveys of Delta fish. Photo: California Department of Fish and Wildlife

Lee Miller, the biologist in charge of the surveys, started preserving the smelt catches for me. Each year for three years a pickup loaded with quart bottles of delta and longfin smelt would arrive at my laboratory. For a diet study alone, my technician and I dissected 1,055 delta smelt.

Today, few delta smelt remain in the wild. Researchers get their samples from special labs where the smelt are bred in captivity.

The state’s 2014 fall mid-water trawl survey showed the lowest number of delta smelt in 47 years of recordkeeping (See chart below). Last week, the state conducted its annual spring Kodiak trawl survey, which is designed to capture delta smelt as they aggregate to spawn. They caught only six smelt — four females and two males [1] [2].

Delta smelt annual abundances as determined by fall midwater trawl surveys. Source: California Department of Fish and Wildlife

Delta smelt annual abundances as determined by fall mid-water trawl surveys. Source: California Department of Fish and Wildlife

The dismal catch prompted me to advise the state’s Delta Stewardship Council on Monday that delta smelt appear to approaching the point of no return, with extinction in the wild possible in the next year or two.

Source: California Department of Fish and Wildlife

Distribution of female delta smelt in March 2015, as determined by the annual spring Kodiak trawl survey. Source: California Department of Fish and Wildlife

I say “in the wild” because there are two captive populations of smelt. The U.S. Fish and Wildlife Service manages a backup population at its fish hatchery below Shasta Dam, and UC Davis produces smelt for experimental and conservation purposes at a lab in the Delta, just south of Stockton. Both facilities raise hundreds of smelt at a time through their entire life cycle. Each fish is tagged and its genetics recorded for precise mating, to maximize genetic diversity. Each year a few wild smelt are brought in to mix their genes with those of the captive brood stock. 

Delta Smelt Refuge facility with tanks for genetically diverse smelt populations.

Delta smelt rearing tanks in captive breeding facility run by UC Davis near Stockton. Photo by Dale Kolke California Department of Water Resources

We don’t know what the minimum population size has to be for successful reproduction to occur in the wild. But it must be hard for males and females to even find one another today, and even harder to find partners that are in the right stage of maturity for spawning. Most of these fish have a one-year life cycle, apparently dying after spawning. A few live two years. This means a bunch of them have to spawn successfully every year to maintain a viable population.

We don’t know with absolute certainty that wild delta smelt will disappear within the next couple of years. But the likelihood is high enough that we should be prepared for it. We need to start answering questions like these:

  • How do we know when the delta smelt is truly extinct in the wild? Who makes the decision? It is worth noting that the last thicktail chub was caught in the Delta’s Steamboat Slough in 1957 but not recognized as extinct for at least 30 years — and without an official declaration.
  • Should the last of the delta smelt be captured so their genes can be added to the captive population, as was done for the California condor?

    Counting Delta Smelt eggs, one inch in the tube means 1000 eggs. Dale Kolke

    Counting delta smelt eggs. One inch in the tube means 1000 eggs. Photo by Dale Kolke, California Department of Water Resources

  • Can captive populations be used to restore the delta smelt in the wild? This is not easy to answer. Obviously, this would not work as long as conditions that caused the smelt to decline remain. These conditions include competition and predation by alien species, altered food supply, multiple water contaminants and water exports upstream and within the Delta. The extended drought presumably has worsened these conditions and pushed the smelt over the edge of the extinction cliff, or at least close to it [3].
  • How does management of the Delta change if delta smelt are extinct in the wild? It is hard to do anything water-related in the Delta without considering its impacts on delta smelt, particularly operation of state pumping facilities and wastewater treatment plants. For example, in the past year federal fish officials placed no restrictions on pumping from the South Delta because the smelt were mostly not there.

Presumably, protecting delta smelt has benefited other native fish because it is the species most sensitive to changes in the Delta’s waterways. Other listed fish species that affect and are affected by Delta management include winter- and spring-run Chinook salmon, longfin smelt, green sturgeon and Central Valley steelhead.  

We need to prevent more fish from achieving the cliff-hanger status of delta smelt. We need to extend proactive management from species already listed to those headed in that direction, including hitch, blackfish, splittail, tule perch and white sturgeon. This requires learning more about their requirements and managing parts of ecosystem specifically for their benefit, including tidal marshes.

I hope we still have enough smelt and enough time to keep the species from altogether disappearing from the Delta. But, as my geologist colleague Jeffrey Mount is fond of saying, “Hope is not a strategy.” We need to be planning for delta smelt extinction and, perhaps, its resurrection.

Peter Moyle, a professor of fish biology, is associate director of the Center for Watershed Sciences at UC Davis.

[1] Numbers were much higher in 2002 – 2014 (e.g., Bennett 2005). Intensive Kodiak trawl surveys near the state and federal water projects (Jersey Point) in 2014 caught so few fish that the U.S. Fish and Wildlife Service placed no restrictions on Delta pumping that year. In 2013, this survey captured 329 smelt in 737 tows of the trawl, with 78 percent of the tows catching no fish. This may seem like a high number but the high-intensity sampling spanned a two-month period when smelt populations should be at their peak. Presumably few, if any, of the highly sensitive fish survived the experience.

[2] The numbers of delta smelt are only a fraction of what they were in 1993 when both the state and federal governments listed the species as “threatened” with extinction.. The designation occurred because its numbers were a small fraction of those in the early 1980s when the population decline began..

[3] At the very least, reintroduction would have to wait until we had some wet years with lots of inflow from the rivers. But if we wait too long for reintroduction, the smelt may not be capable of living on their own in the wild. Having multiple generations in captivity tends to alter behavior and general ‘fitness’ of fish. The problems hatchery salmon have surviving in the wild are a reflection of this lack of natural selection.

Further reading 

Bennett WA. 2005. “Critical assessment of the delta smelt population in the San Francisco Estuary,” California. San Francisco Estuary & Watershed Science 

Quinton, A. 2015. “Endangered delta smelt may be extinct.” Capital Public Radio. March 16, 2015

Ruyak B. 2015. “UC Davis fish biologist: delta smelt ‘functionally extinct’.” Capital Public Radio, Insight with Beth Ruyak. March 18, 2015


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Salmon finding a home in my backyard – Could it be?

Chinook salmon spawning in Lower Putah Creek, 2014. Photo by Ken Davis/Wildlife Survey and Photo Service

Chinook salmon spawning in Lower Putah Creek, 2014. Photo by Ken Davis/Wildlife Survey & Photo Service

By Peter Moyle

The sound of splashing drew me to the stream. A dark finned back cut the surface. Salmon? The fish came into view and its snout was a giveaway, maroon-hued and curved like a hook.

This was a spawning male Chinook salmon. It alternated between chasing another hooknose and two jacks, small males that sneak in to add their sperm to the mix when a standard male and female are spawning.

The source of the commotion soon became clear: A mottled female was turned on her side and fluttering her tail in a patch of clean gravel, digging a nest, or redd. Several small rainbow trout hovered nearby, waiting to feast on loose eggs.

Video shows Chinook salmon spawning in Lower Putah Creek, Yolo County, in fall 2014. No sooner does a female lay her eggs than she is flanked by two males, mouths agape as they release clouds of sperm. The female attempts to bury her eggs as several rainbow trout attempt to eat them. Poor girl even hits her head on a rock while covering the eggs. Video by Ken Davis/Wildlife Survey & Photo Service

The scene I’m recalling from December was not the Sacramento River or some other salmon highway, but a lowly back alley long associated with carp and suckers: Putah Creek, my hometown stream west of Sacramento.

Shortly after my find, I was involved in a discussion about a new bridge being built on the creek in the Yolo County community of Winters. Chinook salmon had recently been seen spawning at the construction site. Workers were preparing to remove temporary supports from the span. Would the embryos buried in the gravel be destroyed in the process?

Until recently, such concerns would have been inconceivable. Though Putah Creek has been heralded since 2000 as a success story in stream restoration, salmon have been regarded mainly as a bonus. Few salmon have responded each year to a special pulse flow designed to coax them upstream to spawn in the cold waters at the foot of Putah Diversion Dam.[Listen to Peter Moyle’s story of how Putah Creek got its fish flows back (2 mins)]

Lower Putah Creek. Source:

Lower Putah Creek. Source: Teale GIS Solutions Group, US Census Bureau, USGS


This past fall, however, more than 200 salmon came up the creek and spawned, or tried to, using every patch of gravel between the dam and the UC Davis campus, including the patch by the new bridge.

The number is tiny compared with the thousands of salmon that return annually to California’s Central Valley. But it’s the highest population recorded in the 30 years, when my UC Davis students began taking annual fish surveys of Putah Creek. The previous high was about 70 salmon, a decade ago. In most years fewer than 10 salmon can be found in the 27-mile-long stream below the diversion dam. Putah Creek has its headwaters in the Mayacamas Mountains that divide the Napa and Sonoma valleys and once spawned in the now-drowned Berryessa Valley.

Most of this past fall’s salmon run used the freshly “ripped” gravel in the first few miles below the diversion dam. The Solano County Water Agency, which operates the dam, greatly increased the chances of a productive spawn by ripping through the concrete-like layer of clay and sand covering the gravel. Using heavy machinery, the agency’s Rick Fowler uncovered smooth stones of many sizes, ideal for spawning. As an experiment, alternating stretches of the creek were left as they were. Not surprisingly, no salmon spawned in these areas.

So why the sudden influx of salmon into Putah, during a drought no less? The reasons reflect the many challenges California faces trying to retain self-sustaining salmon populations.

Ken Davis

Ken Davis, a Sacramento wildlife photographer and aquatic biologist, recorded salmon spawning last fall here on Lower Putah Creek. Photo by Peter Moyle

The most optimistic reason is that this year’s spawners are progeny of earlier spawners, 2 to 3 years ago. We have observed juvenile salmon migrating downstream during the spring, and local naturalist Ken Davis has recorded juveniles summering in the cold water below the diversion dam. Presumably these fish moved out as the water cooled in the fall, especially after a rain.

However, it is more likely that most of this year’s salmon were strays from hatcheries. About 25 percent of hatchery fish are marked by removing the adipose fin and we observed carcasses with this fin missing.

The large number of hatchery strays could be explained by a series of events in the first week of December.

At the mouth of Putah Creek, a man-made canal known to trap wayward salmon drew an unusually large number of strays. The heavy rain that week could have accounted for this. Flush with stormwater runoff, water flowing from Cache Slough into the Sacramento River could have been as attractive as the low flows from the drought-stricken river itself.

The wrong turn at Cache took salmon up the dead-end canal, known as the Toe Drain of the Yolo Bypass. (A small board dam that sends water to the Yolo Basin Wildlife Area keeps fish from entering Putah Creek until the first week of December, when the boards are removed.) California Department of Fish and Wildlife crews with nets rescued some but not all of the trapped strays and returned them to the Sacramento River.

To salmon remaining in the muddy Toe Drain, Putah Creek would have seemed like an attractive option – especially once the stormwater started flowing down the stream. The first fish up the creek would have found a small board dam in the bypass blocking their way; the dam sends water to the Yolo Basin Wildlife Area until the first week of December, when the boards are removed. Salmon were observed swimming upstream immediately after the boards went off. The biggest influx apparently occurred during with the five days of pulse flow from the diversion dam, which coincided nicely with the inflow of stormwater runoff.

Photo by Chris Jasper

UC Davis science students recently found some small salmon fry in Putah Creek. Photo by Chris Jasper, March 7, 2015.

Whatever the reason for the surge in Putah Creek salmon, I will be watching for young out-migrants in the creek this spring. Earlier this week, a team of UC Davis undergraduates led by Chris Jasper found some small (1.5 inch) fry in the creek on campus. These fish had clearly just emerged from a redd. I can only hope some of these fish are the progeny of naturally produced adults from previous years.

Studies elsewhere have shown that juveniles of wild salmon parents have much higher survival rates than those of hatchery-born salmon, even if those parents spawned in the wild.  

If wild fish are not swamped out each year by less fit hatchery fish, natural selection – evolution – can start to work again, producing fish better able to live under the changing conditions of our rivers.

It would be good to see what is going on in Putah Creek occur in larger rivers, with thousands of fish. This can happen only if we radically change our management of hatcheries and salmon in dammed rivers (Katz and Moyle 2012).

It would be wonderful if every fall families could go to bridges and banks and look down on huge salmon spawning in their local creek. Putah Creek as salmon stream – hold that thought!

Peter Moyle, a professor of fish biology, is associate director of the Center for Watershed Sciences at UC Davis.

Further reading

Case, E. and LeCompte, C. 2014. The Putah Creek Legacy. A five-part multimedia series by The Davis Enterprise and Climate Confidential.

Davis, K. 2014. “Report 4963: 2014 Putah Salmon Run“. Wildlife Survey & Photo Service

Katz, J. and Moyle, P.B. 2012. “Have our salmon and eat them too: Re-thinking Central Valley salmon hatcheries“. California WaterBlog. Feb. 29, 2012

Kiernan J, Moyle P, Crain PK.  2012.  “Restoring native fish assemblages to a regulated California stream using the natural flow regime concept“. Ecological Applications.

Putah Creek Council


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Creating effective groundwater sustainability plans

measure and record a pumping water level in a production well. Photo by XXX, DWR

A California Department of Water Resources (DWR) geologist measures and records a pumping water level in a production well. Photo by John Chacon,/DWR, 2013

Jay Lund, Thomas Harter, Robert Gailey, Graham Fogg, Richard Frank, Helen Dahlke, Timothy Ginn, Sam Sandoval Solis, Thomas Young — UC Davis
Andrew Fisher, Ruth Langridge — UC Santa Cruz
Joshua Viers, Thomas Harmon — UC Merced
Patricia Holden, Arturo Keller — UC Santa Barbara
Michael Kiparsky — UC Berkeley
Todd Greene, Steffen Mehl — California State University, Chico
Jason Gurdak — San Francisco State University
Steven Gorelick, Rosemary Knight — Stanford University

California is entering a new era in how it manages its largest source of water storage — groundwater. Initial efforts implementing the state’s new Sustainable Groundwater Management Act must focus on getting local and state agencies organized and able to communicate with each other. Having common expectations for the contents of the law’s required “Groundwater Sustainability Plans” will save the agencies and stakeholders considerable grief and confusion. Here is how the contents of the local plans might be organized to support both local and statewide objectives for groundwater sustainability.

Groundwater plans

The new law, which took effect Jan. 1, broadly defines “sustainability” as avoiding “undesirable results,” [Section 10721 (u)-(w)] in terms of groundwater overdraft, land subsidence, water quality degradation, seawater intrusion and groundwater-surface water interaction. The local sustainability plans are not required to address undesirable results that occurred before Jan. 1 [Section 10727.2 b (4)].

The law requires regional agencies to prepare the Groundwater Sustainability Plans for groundwater basins that the California Department of Water Resources has designated “high” and “medium” priority. The department has preliminarily assigned these designations to 127 of the state’s 515 basins [1].

The law provides a framework for the plans (Section 10727) but refrains from a prescriptive state role. It requires the department to create technical criteria and regulations by which it will evaluate the appropriateness of the local plans and their implementation (Section 10733). The department must adopt the regulations before June 1, 2016. The design of these regulations and their technical and scientific requirements will be critical to the success of the plans.

In the coming months, there will be much discussion on the content of these rules among department staff and advisors and in public meetings. The initial 2016 regulations will likely be refined over time [Section 10733.2 b (1)], but all parties have an interest in a well-designed initial regulatory framework to guide the development and evaluation of the local sustainability plans.

Making the local plans effective

To be effective, the plans must be based on the physical realities of geology, hydrology and land use. Groundwater balances are central. However, groundwater sustainability might not simply balance basin pumping with natural recharge; under natural conditions inflow is balanced by natural outflow to streams and groundwater-dependent ecosystems. Today, additional stream depletion and deep percolation of irrigation water increase total basin inflows.

Photo by Kelly M. Grow/California Department of Water Resources

Delivery point of the Coachella Valley Water District’s groundwater replenishment facility. Photo by Kelly M. Grow/California Department of Water Resources

Plans also should be realistic on local, economic, political and legal conditions, including logistics in implementation and relationships to neighboring plans and finances. The plans also must clarify the responsibilities and authorities of local agencies for implementation, and specify contingencies for when conditions deviate from plan assumptions or projections (including surface water deliveries and inflows from other basins).

“Groundwater Sustainability Agencies” responsible for developing basin plans will need to make controversial decisions. The state regulations should require transparent development of sustainability objectives and analysis to inform decision-makers, regulators and courts. The technical information should include:

  • Local concerns, objectives and definition of “sustainability”
  • Water balances for the basin under present and potential future conditions
  • Data collection and reporting to inform, monitor and evaluate analyses and plans
  • Overall assessment of groundwater basins
  • Management alternatives available to achieve local sustainability objectives
U.S. Geological Survey scientists say cracks and buckles along the Delta-Mendota Canal are likely caused by subsidence from groundwater overdraft. Photo by Amy Quinton, Capital Public Radio, November. 2013 by Amy Quinton, Capital Public Radio

U.S. Geological Survey scientists say cracks and buckles along the Delta-Mendota Canal are likely caused by subsidence from groundwater overdraft. Photo by Amy Quinton, Capital Public Radio, November. 2013 

Each major management alternative should be technically assessed on its likelihood of success as well as its cost (including delayed costs and those to third parties) and performance — physical, economic, social and environmental. Science-based planning and management requires that contingencies be flexible enough to accommodate major unavoidable uncertainties.

Clear and timely communication among stakeholders will be critical to reduce conflict and build creative solutions with broad local support. This requires:

  • Data organization, transparency and availability
  • Sharing knowledge, concepts, management options and assessment of desirable and undesirable outcomes
  • Examination of uncertainties in knowledge, data and predictability of outcomes
  • Clear analytical comparison and discussion of alternatives leading to a preferred plan

Crafting the Groundwater Sustainability Plans so they can be effective on (and under) the ground and fairly evaluated by state regulators and courts is an immense technical and institutional challenge. Thoughtful state regulations on the development and contents of these plans will be essential.

A proposed table of contents

Here we propose a preliminary table of contents for a typical Groundwater Sustainability Plan. More details and structure are suggested in an outline that can be downloaded here. This outline includes technical items we believe are needed for effective plans. Tiers of content depend on basin complexity. Additional items might also be useful, and some items might not be needed for simpler cases.

A Table of Contents
Groundwater Sustainability Plans 

  1. Summary statement of local basin sustainability objectives and approaches
  2. Basin geography and GSP organization: description of basin, water sources and uses; Summary of major basin problems related to groundwater; organization of local Groundwater Sustainability Agencies; defining roles and authorities relative to other local and regional agencies
  3. Summary of basin hydrogeology: geologic context of local groundwater; major water flows in and out of basin; changes in storage with time; variability in flows and storage; how flows are likely to change with climate, population, and land use; susceptibility to land subsidence, saltwater intrusion, loss of habitat and other problems related to groundwater use
  4. Sustainability objectives, options and analysis: basin-specific definition and objectives for sustainability (quantity, quality, land subsidence and groundwater/surface water interaction); options and effectiveness for achieving sustainability; groundwater deliveries for different water budget management options, including uncertainties
  5. GSP activities: management activities; implementation responsibilities and enforcement; timelines, funding, measurement and verification; agreements with neighboring and regional basins, water suppliers and land-use authorities on water management and supply and information sharing; strategies for moving forward in the absence of ideal data, including additional near-term data gathering; monitoring plans; recourse contingencies for changes in surface water availability, to make implementation more robust; monitoring plans
  6. Implementation actions supporting GSP activities: near-term actions and responsibilities; efforts and responsibilities for improving information and reducing uncertainties to manageable levels; efforts to assess achievement of plan objectives

Technical appendices:

  1. Basin hydrogeology
  2. Details of water budget component calculations
  3. Water quality, including natural and anthropogenic sources of contamination
  4. Options considered for achieving sustainable management
  5. Process of GSP development, including local and stakeholder engagement and analysis
  6. Details of monitoring and assessment plans
  7. Other supporting documents

PDF file of table of contents
PDF file of more detailed table of contents

[1] Links to further information on the Sustainable Groundwater Management Act of 2014:

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The California Drought of 2015: March

By Jay Lund

Droughts are strange, and this one is becoming scarier.

February began with a nice few stormy days, but has since looked like this January – very dry. And so far, the March forecast is not wet.

At the beginning of March, the Northern Sierra (Sacramento Valley) Precipitation Index was down to 88% of average to date, although it already almost equals total precipitation for all of 2014 (both good and bad news). For the San Joaquin Valley and Tulare basin (where most water use occurs), precipitation is about half of average for this date – slightly wetter than this time last year.  Snowpack is roughly like last year – among the driest on record.

Will March will be as dry?  Statistically, little can be said. There is little correlation in monthly precipitation during Northern California’s wet season, but droughts are inherently unusual.  The forecast and climate conditions so far look dry.

The best news is a bit more overall reservoir storage than last year at this time (but still about 5 maf below average for this time of year).   The big reservoirs in the Sacramento Valley have 1.3 maf more than last year at this time – this is the good news.  South of the Delta surface storage is about the same overall, but differently distributed.  San Luis reservoir, which serves the west side of the valley and southern California is about 600 taf higher, but the large reservoirs on the San Joaquin River tributaries are about 600 taf lower.

Groundwater storage is probably about 6 maf less than last year.

Without a miracle March, we will have another critically dry year for 2015.  Northern California is likely to be a bit better off than last year, but could be about the same (very dry).  In the southern Central Valley and southern California conditions could easily be as bad or worse than last year.

The state is likely to protect environmental flows more carefully this year, probably a good thing to reduce potential for more endangered species listings after the drought.  The State Water Project has said they expect about 15% deliveries.  The federal Central Valley Project has now announced initial 0% deliveries for regular agricultural water contracts, likely cutbacks (of 25%?) for water right exchange and settlement contractors, and 25% urban deliveries for 2015.  While these percentages might improve in the remaining month of the wet season, there is a good chance that water allocations will be similarly dismal to 2014, with less groundwater available in some parts of the state.


Fortunately, some Northern California reservoirs have more storage than a year ago, while reservoir levels elsewhere are more mixed. Overall, we remain about 6 million acre-feet below average for reservoir storage this time of year.  In the southern Central Valley, west side reservoirs (San Luis) have much more water than last year, but the east side tributaries to the San Joaquin River are very low (Exchequer at 8% of capacity).

Aquifer levels will generally be lower than a year ago in the areas highly dependent on groundwater.

Source: California Department of Water Resources

Source: California Department of Water Resources


Snowpack is truly sad, about 16% of average for this time of year.


The 2014 water year ended at 60 percent of average annual precipitation for Sacramento Valley. For 2015, we’re already about at this total, so 2015 is very likely to be at least a bit wetter than 2014 for the Sacramento Valley.  A very wet March and early April sure would help.

<span style="color: #000000;">For updates, <a style="color: #000000;" href="">click here</a>. <em>Source: California Department of Water Resources</em></span>

For updates, click here. Source: California Department of Water Resources

Both the San Joaquin and Tulare basins are slightly wetter than this time last year.  2015 could be better than 2014, but could also easily be drier.

Source: California Department of Water Resources

For updates, click here. Source: California Department of Water Resources

Source: California Department of Water Resources

For updates, click here. Tulare basin has a shorter record though it has the most water use in California. Source: California Department of Water Resources

The difference between a drought and a wet year in California is just a few storms. We are at two significant storms so far, mostly in the northern state.  There is little time left to make this up, particularly south of the Delta.

Sadly, our standard for 2015 is not  average, but  the miserable conditions of 2014.  That’s how dry it is.

Beware the dries of March.

Jay Lund is a professor of civil and environmental engineering and director of the Center for Watershed Sciences at UC Davis. 

Further Reading

The links above can help keep you up to date. For more data, explore the California Department of Water CDEC web site

Lund, J. “The California Drought of 2015: January” California WaterBlog. Jan. 5, 2015

Lund, J. and J. Mount. “Will California’s drought extend into 2015?California WaterBlog. June 15, 2014

Swain, D. “The Ridiculously Resilient Ridge Returns; typical winter conditions still nowhere to be found in CaliforniaCalifornia Weather Blog. Feb. 16, 2015

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Dutch lessons on levee design and prioritization for California

Dutch flood safety standards, established by economic risk analysis. Source: Flood Defence Act of 1996

Dutch flood safety standards, established by economic risk analysis. Source: Flood Defence Act of 1996

This is the second of an intermittent series of articles on the future of the Sacramento-San Joaquin Delta.

By Jay Lund

In any lowland, levees define how humans live and how they disrupt native habitats. This is as true for the Sacramento-San Joaquin Delta as it is for coastal Louisiana, Vietnam and the Netherlands.

Flood safety in the Delta is a statewide concern because the region serves as a hub for delivering water to most Californians and supports native fish.

Like many Dutch lowlands, the Delta became low from the conversion of tidal marsh to farmland. Once diked and drained, peat soils (accumulating over millennia with sea level rise) were exposed to air, decomposed and subsided. Dutch lowlands have sunk about 6 feet in 300 years, while some islands in the western and central Delta have subsided much more — up to about 25 feet over 150 years — because of California’s warmer and sunnier climate.

Administration of Dutch polders (islands)

The Dutch have a long and distinguished record of managing floods in their lowlands. They have been reclaiming dry land from the sea and marshlands since the Middle Ages. They have suffered and learned from centuries of flooding.

Local landowners did most of the land reclamation and paid for the work themselves. As the country grew, it consolidated the governance of reclamation from what were once thousands of local “water boards” to 24 regional boards, which maintain levees and dikes and treat wastewater.

Consolidation and growing prosperity brought more state involvement and funding for flood protection, along with more formal state protection standards and prioritization. Investments in flood protection are now guided by formal analyses of risks, costs and benefits (van Dantzig 1956).

Risk analysis

The Dutch risk analysis has provided a rigorous, understandable and widely accepted basis for flood management decisions and investments for nearly 60 years (Eijgenraam et al 2014, Schweckendiek 2013). The level of flood protection is chosen to minimize the total costs of flood damage and protect investments.

Using risk analysis to balance benefits and costs of flood protection (Schweckendiek 2013)

Using risk analysis to balance benefits and costs of flood protection Source: Schweckendiek 2013

Having risk analysis drive the setting of flood safety standards and investment priorities follows a long Dutch tradition of improving analytical tools to solidify the scientific basis of decision-making (Disco and van der Ende 2003).

The risk analysis has grown to include loss of life, longer planning horizons, sea level rise and more subtle aspects of levee system reliability – aspects that have led to better management of levees and floods (Eijgenraam et al. 2014, Jonkman et al 2011; Schweckendiek 2013).

The Dutch sometimes have retreated from the sea following catastrophic storms, or by design to increase flood conveyance capacity, restore natural areas and reduce costs. The Netherlands has setback some levees, widened some channels and “de-poldered” or abandoned some subsided land under its “Room for the River” program (van Staveren et al. 2014).

Implications for California’s Delta?

For the Delta, state levee decisions are probably the single most important and defining policy area. Living in the Delta and in lowlands elsewhere in the world is largely defined by the design and maintenance of levee systems and the prioritization of levee projects. The flow and mixing of water is shaped by the configuration and reliability of levee systems and how they fail. (In any system, levees will fail, and part of levee policy is what to do when they fail.) Levee systems also shape the remaining natural habitat for native species and other important habitat, such as the Delta’s famous bass fishery.

Where levee system design is so fundamentally important to so many interests, it is tempting to perform highly complex analysis of many alternative management strategies for each of the many social, economic and environmental interests in the region. However, thoughtful analysts and policymakers know such analyses can do more to confuse than enlighten.

The Dutch have brought three useful ideas to the design of their lowland levee system:

  • Define problems in ways they can be solved. The Dutch have defined their levee problem in a way that can be usefully solved, even if the definition is necessarily incomplete. Indecision or perpetuation of a deteriorating status quo is dangerous in lowlands. The Dutch begin by examining the economic benefits, costs and risks in levee system design. Economic sustainability and public safety are the major objectives for levees below sea level. Additional social and environmental concerns are considered separately. This process clarifies trade-offs and avoids more complex approaches that tend to add more confusion than insight.
  • Base levee standards and safety levels mainly on risk analysis. Economically and environmentally, some areas merit higher levels of flood protection than others. Some areas may deserve no flood protection at all. In other cases, flooding may benefit the environment.
  • Consolidate levee districts. Most levee maintenance is a local responsibility that is funded and inspected by the state. Long-term consolidation has resulted in more responsible use of state funds and better flood protection for more land.

California’s Delta has many unique challenges (Finch 1985; Lund et al 2010; Lund 2011), but much can be learned from the efforts and successes in the Netherlands (Woodall and Lund 2009; Ertsen and Lund 2011).

If we want to solve hard problems, we must define and organize them in ways that can be solved, even imperfectly. Indecision risks everything in lowlands – local lives and livelihoods, a water system serving millions of Californians and acres of farmland, and important habitat for native aquatic species. Nostalgia for the Delta of the 1950’s or 1850’s cannot prevail for long over the hard physics and economics of lowland risks.

Jay Lund is a professor of civil and environmental engineering and director of the Center for Watershed Sciences at UC Davis.

A note on Delta terminology

California has a long tradition of improperly naming physical features in the Sacramento-San Joaquin Delta, beginning with the term delta.

A river dike between Kesteren and Opheusden, the Netherlands, at high water levels oo the river Nederrijn in 1995. Photo by Henri Cormont/Wikimedia Commons

Throughout the rest of the world (with the exception of the Okavango Delta), deltas are formed where rivers disgorge into open bodies of water, leaving a prism of sediment shaped like the Greek letter Δ (delta)The Sacramento-San Joaquin “Delta” does not qualify as a traditional delta since it is formed at the tidally influenced confluence of two large floodplain rivers, which was submerged more than 6,000 years ago by sea level rise.

Other common misnomers are levees and islands. Levees are earthen embankments that hold back water during floods. The Delta “levees” are actually dikes because they hold back water all the time.

Islands are lands of positive relief surrounded by water. The Delta’s “islands” are reclaimed lands that form topographic depressions surrounded by water. In this regard, they are polders, not islands.

The Dutch, who have many dikes maintaining polders in their delta landscape, go by more authoritative terminology.

Further reading

Buijs, F.A., P.H.A.J.M. van Gelder, J.K. Vrijling & A.C.W.M. Vrouwenvelder, J.W. Hall, P.B. Sayers, M.J. Wehrung (2003), “Application of Dutch reliability-based flood defence design in the UK,” Safety and Reliability – Bedford & van Gelder (eds), Swets & Zeitlinger, Lisse, ISBN 90 5809 551 7

Disco, C. & J. van der Ende (2003), “Strong, Invincible Arguments?: Tidal models as management instruments in twentieth-century Dutch coastal engineering,” Technology and Culture, Vol. 44, July, pp. 502-535

Eijgenraam, C., J. Kind, C. Bak, R. Brekelmans, D.k den Hertog, M. Duits, K. Roos, P. Vermeer, W. Kuijken (2014), “Economically Efficient Standards to Protect the Netherlands Against Flooding,” Interfaces, Vol. 44, No. 1, January–February, pp. 7–21

Ertsen, M. and J. Lund, “Drowning Men Will Clutch at Straws – A Short Comparative History Of Dutch And Californian River Flood Management,” 25th ICID European Regional Conference Proceedings, Paper IV-5, 2011

Finch, M. (1985), “Earthquake Damage in the Sacramento-San Joaquin Delta, Sacramento and San Joaquin Counties,” California Geology.

Jonkman,S.N, R. Jongejan, and Bob Maaskant (2011),”The Use of Individual and Societal Risk Criteria Within the Dutch Flood Safety Policy—Nationwide Estimates of Societal Risk and Policy Applications,” Risk Analysis, Vol. 31, No. 2

Kind JM (2013) “Economically efficient flood protection standards for the Netherlands,” Journal of Flood Risk Management

Lund, J., E. Hanak, W. Fleenor, W. Bennett, R. Howitt, J. Mount, and P. Moyle, Comparing Futures for the Sacramento-San Joaquin Delta, University of California Press, Berkeley, CA, February 2010

Lund, J.R. (2011), “Sea level rise and Delta subsidence—the demise of subsided Delta islands,” California WaterBlog, posted March 9, 2011

Mostert, E. 2012. “Water management on the island of IJsselmonde 1000 to 1953: polycentric governance, adaptation, and petrification.” Ecology and Society 17(3): 12

Room for the River program

Schweckendiek, T. (2013), “Dutch approach to levee reliability and flood risk,” presentation to the National Research Council

Suddeth, R., J. Mount, and J. Lund (2010), “Levee decisions and sustainability for the Sacramento-San Joaquin Delta,” San Francisco Estuary and Watershed Science, Volume 8, No. 2, 23 pp

Suddeth, R. (2011), “Policy implications of permanently flooded islands in the Sacramento–San Joaquin Delta,” San Francisco Estuary and Watershed Science, 9(2)

van Dantzig, D. (1956), “Economic decision problems for flood prevention,” Econometrica 24(3):276–287

van Staveren, M.F., J.F. Warner, J.P.M. van Tatenhove, and P. Wester (2014), “Let’s bring in the floods: de-poldering in the Netherlands as a strategy for long-term delta survival?”, Water International, Vol. 39, No. 5, pp. 686-700

van der Vleuten, E. and C. Disco (2004), “Water Wizards: Reshaping wet nature and society.” History and Technology 20 (3), 291-309

Voortman, H.G. (2003), “Risk-based design of large-scale flood defence systems” PhD thesis, TU Delft, The Netherlands. Also published in the series “Communications on Hydraulic and Geotechnical Engineering” Delft University of Technology, Report no. 02-3

Voortman, H.G. and J.K. Vrijling (2004), “Optimal design of flood defence systems in a changing climate.” Heron, Vol. 49, No. 1

Vrijling, J.K., W. van Hengel, and R.J. Houben (199), “Acceptable risk as a basis for design.” Reliability Engineering and System Safety, 59:141-150

Walker, W. E., A. Abrahamse, J. Bolten, J.P. Kahan, O. Van De Riet, M. Kok, and M. Den Braber (1994), “A Policy Analysis of Dutch River Dike Improvements: Trading off Safety, Cost, and Environmental Impacts,” Operations Research, Vol. 42, No. 5

Woodall, D.L. and J.R. Lund (2009), “Dutch Flood Policy Innovations for California,” Journal of Contemporary Water Research and Education, Issue 141

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