Reconciling ecosystem and economy

Ecologist Michael Rosenzweig kicked off a UC Davis series of public talks exploring a “reconciliation” approach to improving California’s aquatic habitat. Video: UC Davis Center for Watershed Sciences.

A growing number of ecologists say we need to rethink how we go about “saving nature.” We should not attempt to restore a wounded meadow, estuary or wetland to some legendary pristine state, they say. Instead, resource managers should accept that human footprints are everywhere and manage ecosystems for the species and functions we desire.

The approach, known as “reconciliation ecology,” inspired a UC Davis seminar earlier this year on how to manage California’s water systems for both ecosystem and economic objectives. The Center for Watershed Sciences and the California Environmental Law & Policy Center at UC Davis lined up a series of nine public talks by ecologists, biologists, engineers, lawyers and environmental consultants. California water journalist Chris Austin summarizes the presentations.

By Chris Austin

Michael Rosenzweig, a University of Arizona ecologist who first articulated the concept of reconciliation ecology, kicked off the UC Davis seminar on Jan. 6 with his talk “Tactics for Conserving Diversity: Global Vertebrate Patterns Point the Way.”

Reconciliation ecology, in Rosenzweig’s own words, “is the science of inventing, establishing and maintaining new habitats to conserve species diversity in places where people live, work and play.”

Rosenzweig outlined the scientific basis for his assertion that human encroachment on wildlands will continue to cause species extinctions and loss of biodiversity at alarming rates. But his was also a message of hope: We can reverse the trend by changing our human-dominated landscapes in ways that favor desirable species.

Although Rosenzweig first coined the term in the early 2000s, the concept of reconciliation ecology is not new. Efforts to create habitat around the densely developed edges of San Francisco Bay have been underway for the past 25 or more years.  In the Feb. 10 seminar, Reconciling Ecosystem Goals for the San Francisco Bay, Letitia Grenier, a biologist specializing in landscape-scale planning, and Joe LaClair, chief planning officer for the Bay Conservation Development Commission, discuss the challenges of protecting both critical infrastructure — highways, airports, rails — and healthy ecosystems against climate-induced sea level rise in the Bay Area. Grenier is updating the San Francisco Estuary Institute’s 1999 blueprint for restoring of 100,000 acres of tidal marsh around the Bay.

Putah Creek: A ‘novel’ ecosystem

Aquatic habitat restoration projects traditionally have aimed to remove non-native plants and fish introduced by humans, but UC Davis fish biology professor Peter Moyle says most of these alien species do not cause significant harm. Instead, he said, they integrate with native species to form “novel ecosystems” that are often quite different from what historically might have existed.

Moyle and UC Davis researcher Melanie Truan told the story of one such novel ecosystem in their Jan. 13 talk, A Reconciliation Approach to Aquatic Ecosystems in California. Beginning in the 1980s, Davis area students, scientists and local residents took the local Putah Creek from a trashed waterway that was heavily mined for gravel to a healthy stream where both native and non-native fish flourish. Key to the success were changes in dam operations that provided more natural flows at biologically important times but with relatively small amounts of water.

Yolo Bypass: Using floodwaters to boost salmon populations

The seminar title and theme — Reconciling Ecosystem and Economy — was perhaps best illustrated by the Feb. 24 panel presentation, Farms, Floods, Fowl and Fish on the Yolo Bypass.

A consortium of private landowners, conservation groups, government agencies and researchers with the UC Davis Center for Watershed Sciences is investigating how the heavily modified 57,000-acre floodplain used for flood control, farming and duck hunting could also be managed to rear Chinook salmon. Their recent studies indicate that the bypass would make a productive salmon nursery at relatively little cost to farmers. The floodway also is being considered for significant infrastructure changes and habitat restoration as part of the Bay Delta Conservation Plan.

UC Davis doctoral student Robyn Suddeth kicked off the panel discussion with a presentation of an optimization model she designed to explore when, where and how floodwaters might most economically be applied to manage all the diverse activities.

Robyn Suddeth presented a reconciliation approach to managing the Yolo Bypass for multiple environmental and economic objectives. Video: UC Davis Center for Watershed Sciences 

The prospects and science of reconciliation in the Delta

With its numerous conflicting water demands and growing populations of invasive species and looming sea level rise, continued change in the Sacramento-San Joaquin Delta is certain. In her March 27 talk, Money, Water and Fish: Prospects for Reconciliation, Ellen Hanak, a senior fellow with the Public Policy Institute of California, explored the possibilities of taking a reconciliation approach in adapting to these changes, outlining the environmental, social, financial and legal issues involved.

The March 10 panel discussion, Science and Ecosystem Reconciliation in the Delta, focused on the multiple scientific efforts to improve the ecological functions in the Delta’s highly altered environment. The event brought together Peter Goodwin, lead scientist at the Delta Stewardship Council, ecologist Robin Grossinger of the San Francisco Estuary Institute, Stuart Siegel of the Wetlands and Water Resources consulting firm and scientist Valerie Connor of the State and Federal Contractors Water Agency.

California’s water system 

Managing for ‘co-equal’ goals. California’s vast network of water infrastructure delivers water from the north to irrigate millions of acres of farmland in the Central Valley and to support urban populations in the Bay Area and Southern California. 

These dams and reservoirs provide water for cities and farms as well as vital flood protection for downstream communities. At the same time, this infrastructure blocks access to upstream habitat for native species, alters their downstream habitat and disturbs natural flow patterns.

In recent years, plummeting populations of native species have meant tighter environmental restrictions and reductions in water available for human use. Clearly, California’s current system of water management is not working for either water suppliers or endangered species.

In the Jan. 27 seminar, Management, Economics and Engineering Perspectives on Reconciliation Ecology, Tim Quinn, executive director of the Association of California Water Agencies, and Jay Zeigler, director of external affairs at the Nature Conservancy, found much common ground in their views on balancing California’s co-equal goals of water system reliability and ecosystem restoration.

Jay Zeigler and Tim Quinn exchanged views on how better to managed California’s overall water system for a healthier environment and economy. Video: UC Davis Center for Watershed Sciences

Unmanaged groundwater. Groundwater comprises about 30 percent of the state’s water supply in an average year, and far more in a drought year. Yet while the state regulates surface waters through a water right system, groundwater pumping continues to go largely unmanaged. Associate Justice Ronald B. Robie of the California Court of Appeal and Harrison “Hap” Dunning, UC Davis professor emeritus of environmental law, discussed history and environmental and economic tradeoffs in groundwater law in their March 3 seminar, Environmental Reconciliation and the Law.

Water law. Balancing the multiple uses of the state’s waters for both ecosystem and economic purposes is the task assigned to the State Water Resources Control Board, and it’s always complex and oftentimes controversial.

Michael Lauffer, chief counsel for the State Water Resources Control Board, gave a glimpse into the multiple environmental and economic considerations board members and staff must weigh in regulating water rights and water quality the Feb. 3 panel discussion,  A Regulator Perspective on Reconciliation Ecology. Brian Gray and Richard Frank, environmental law professors at UC Hastings College of Law and UC Davis School of Law, respectively, explained how the “reasonable use” and “public trust” doctrines of California water law often come into play in balancing environmental and economic water uses.

Videos of all nine one-hour presentations in the seminar series can be viewed here.

Chris Austin is the author of Maven’s Notebook, an independent online chronicle of California water policy, politics and science.

Further reading

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

Moyle, P. B., W. Bennett, J. Durand, W. Fleenor, B. Gray, E. Hanak, J. Lund, and J. Mount. 2012. “Where the Wild Things Aren’t: Making the Delta a Better Place for Native Species.” San Francisco: Public Policy Institute of California.

Moyle, P. B.  2013.  Novel Aquatic Ecosystems: The New Reality For Streams In California And Other Mediterranean Climate Regions. River Research and Applications.

Rosenzweig, M. 2003. Win-Win Ecology: How the Earth’s Species Can Survive in the Midst of Human Enterprise. Oxford University Press.

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Weathering the drought by drawing down the bank

Ground view showing drought conditions in agriculture field.

Drought conditions in crop field. Source: California Department of Water Resources

By Richard Howitt, Josué Medellín-Azuara, Duncan MacEwan and Jay Lund

Today, UC Davis Center for Watershed Sciences economists join the California Department of Food and Agriculture in releasing a second, more comprehensive and forward-looking report estimating the effects of the California drought on farm production. (UC Davis news release, Video of national press briefing)

The study comes as California endures its third driest year on the 106-year record, and as agricultural, urban and environmental demands for water are at an all-time high.

Based on surveys of irrigation districts and modeling results, growers will lose about 6.6 million acre-feet of surface water availability for 2014 because of the drought. However, additional groundwater pumping is expected to make up for about 5 million acre-feet or 75 percent of the loss. This shift to groundwater, particularly in the Central Valley, will increase the proportion of farm water supplies from groundwater to more than 50 percent, up from about 30 percent the previous year.

The resulting net water shortage of 1.6 million acre-feet will cause losses of $810 million in crop revenue and $203 million in dairy and other livestock value, plus additional groundwater pumping costs of $454 million. These direct costs to agriculture total $1.5 billion. The total statewide economic cost of the 2014 drought is $2.2 billion, with a total loss of 17,100 seasonal, part-time, and full-time jobs.

The 2014 drought is responsible for the greatest absolute reduction in water availability for California agriculture ever seen. In addition, two of the major drought coping mechanisms in California — groundwater pumping and water markets — are being used with little information gathering on their long-term consequences. While our aggregate measures of groundwater depth over time and space are often good, our estimates of regional groundwater use are lacking.

The lack of groundwater pumping information precludes most forms of regional groundwater management. Water markets also are operating in a largely informal manner with reports of extremely high prices being paid throughout the Central Valley – prices at least three times those seen in the 2009 drought. The absence of a central clearinghouse for water-trade information prevents normal market information on current prices and quantities from being available to buyers and sellers.

Thanks to groundwater use and water market transfers, the overall California agricultural economy is weathering the worst drought in decades remarkably well. But the resilience is tenuous because the state’s uniquely unmanaged system of groundwater use runs like an unlimited savings account.

Failure to balance the checkbook – replenishing groundwater in wet years – is putting the nation’s produce basket at risk, particularly California’s more profitable permanent crops such as almonds and wine grapes.

Groundwater availability and use is the key to agricultural prosperity in droughts.

Statistically, the drought is likely to continue through 2015 – regardless of El Niño conditions. If the drought continues, groundwater substitution will remain the primary response to surface water shortage. But the ability to pump groundwater will lessen and pumping costs will climb as water levels fall.

A continued drought also increases agriculture’s vulnerability. Urban water users are for the most part adequately stocked this year, but they are likely to buy water from agricultural areas if the drought persists.

Several public policy improvements could enhance California’s ability to deal with future droughts:

Groundwater measurement and management. Currently California is the only western state without measurements of major groundwater use. A first step to local groundwater management — as opposed to groundwater regulation — is to measure pumping. Two bills under consideration in the state Legislature would provide incentives for more management of groundwater, helping to assure support for crops during a drought.

Environmental Impact Reports for water trades. Water trading is another key to successful drought management.  Some water trades can induce adverse environmental impacts, so EIRs are needed. However, environmental concerns should not be used to block trades for non-environmental reasons. This happened to several proposed water trades during the 2009 drought. A policy solution is to define a programmatic EIR for water transfers that can be assessed prior to a drought. If the pre-drought EIR is approved, then the transfer can proceed, with any subsequent damages adjudicated after the fact. This policy change would lower the costs of water transfers and provide greater predictability and flexibility during a drought.

A water trade clearinghouse (or ISO). The surface water distribution system in California is an interdependent network of individually run canals, reservoirs and rivers. Coordinated operating agreements and contracts exist among some agencies, but moving water efficiently under drought conditions could be improved. California’s water system has parallels to the state’s electricity grid system before its reorganization. Today, California’s electric power is routed and dispatched with a market and prices managed by an Independent System Operator (ISO). A similar water ISO might operate to improve adaptability and responsiveness (Hanak et al 2011). It would take significant federal and state level political impetus to implement a similar system for water, but it remains a promising policy innovation.

We should further develop drought water markets to re-distribute water to crops with the highest economic value while compensating selling farmers. And we need to treat groundwater like a reserve bank account so it will be there to sustain our agricultural bounty in future droughts.

Richard Howitt is a professor emeritus of agricultural and resource economics, 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. Duncan MacEwan is with ERA Economics in Davis, Calif. They are co-authors of the report, Economic Analysis of the 2014 Drought for California Agriculture, which was released July 15, 2014.

Crop Revenue Reductions for 2014 Drought, Central ValleySource: Economic Analysis of the 2014 Drought for California

 Crop Acreage Reductions for 2014 Drought, Central ValleySource: Economic Analysis of the 2014 Drought for California AgricultureSource: Economic Analysis of the 2014 Drought for California Agriculture

Difference in in idle Central Valley cropland between 2014 and 2011, relative to total cropland in each region. Based on NASA satellite maps. Source: Economic Analysis of the 2014 Drought for California Agriculture

Difference in in idle Central Valley cropland between 2014 and 2011, relative to total cropland in each region. Based on NASA satellite maps. Source: Economic Analysis of the 2014 Drought for California Agriculture

Further reading

Lund, J.R., Mount, J. (2014). Will California’s drought extend into 2015? California WaterBlog. June 15, 2014

Lund, J.R., Medellin-Azuara, J., Harter, T. (2014). Why California’s agriculture needs groundwater management. California WaterBlog. May 26, 2014

Lund, J.R., et al. Taking agriculture conservation seriously. California WaterBlog. March 15, 2011

Grabert, V.K., Harter, T., Parker, T. (2014). Modernizing California’s groundwater management. California WaterBlog. June 22, 2014

Howitt, R.E., Medellin-Azuara, J., MacEwan, D., Lund, J.R. and Sumner, D.A. (2014). Economic Analysis of the 2014 Drought for California Agriculture. Center for Watershed Sciences, University of California, Davis, Calif. 20p

Howitt, R.E., Medellin-Azuara, J., MacEwan, D., Lund, J.R. (2014). Preliminary 2014 Drought Economic Impact Estimates in Central Valley Agriculture. Center for Watershed Sciences, University of California, Davis, Calif. 6p

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Challenging myth and mirage in California’s drought

Source: California Department of Water Resources

Source: California Department of Water Resources

In a July 6, 2014 op-ed for The Sacramento Bee, three prominent California water experts challenge some claims that they say are hindering the search for solutions to California’s water shortages. We reprint the commentary here with a sidebar on some of the calculations supporting the article.

By Jay Lund, Jeffrey Mount and Ellen Hanak

As the effects of the drought worsen, two persistent water myths are complicating the search for solutions. One is that environmental regulation is causing California’s water scarcity. The other is that conservation alone can bring us into balance. Each myth has different advocates. But both hinder the development of effective policies to manage one of the state’s most important natural resources.

Let’s consider the first myth, that water shortages for farms are the result of too much water being left in streams for fish and wildlife. Claims are circulating that California’s farms have lost 4 million acre-feet annually because of environmental policies, and some have even suggested that the severe, long-term declines in groundwater levels in the San Joaquin Valley are a result of environmental cutbacks.

Since the early 1990s, efforts to improve environmental conditions have indeed reduced water supply reliability, particularly for San Joaquin Valley farmers who rely on exports from the Sacramento-San Joaquin Delta. But blaming these efforts for today’s critical supply issues vastly overstates the role of environmental regulations.

By our calculations, restrictions on Delta exports, coupled with new restrictions on flows on the San Joaquin River, have cost San Joaquin Valley farmers no more than 1.5 million acre-feet per year in reduced water deliveries — a sizable amount, but far less than 4 million acre-feet. During the current drought emergency, environmental restrictions have been significantly relaxed to make more water available for farms and cities, with most of the remaining Delta outflows dedicated to keeping water in the Delta fresh enough for local farmers.

And while reduced surface water has likely accelerated groundwater overdraft in the Valley – especially since new Delta pumping restrictions in the late 2000s – the notion that environmental restrictions are the origin of overdraft is unfounded.

According to the U.S. Geological Survey, farmers in the Valley have been mining groundwater at an average annual rate of 1.5 million acre-feet per year since long before Richard Nixon signed the Endangered Species Act in 1972. Nothing seems to change this overall pattern, including construction of the State Water Project. Water demand in the San Joaquin Valley simply exceeds available supply. What’s more, the Valley’s water demands are likely increasing with the shift to permanent orchards and vineyards – now more than 40 percent of total irrigated farm acreage.

What about the second myth? Can conservation really create abundant “new” water? Of course, new technology and changing water use habits have yielded long-term declines in per capita water consumption in California, and this drought is likely to spur more reductions. New irrigation techniques and better crop varieties, along with rising commodity prices, have helped California’s agricultural industry steadily increase production and profits. Farmers have become more economically efficient in using their water.

Some claim that potential dramatic yields of more than 10 million acre-feet of new water – equivalent to 10 full Folsom Reservoirs — can be had from conservation measures that draw half from agricultural and half from urban users. But this is just not credible.
In fact, conservation does not always yield new water, because the water saved is often not wasted in the first place — it is already reused.

This is especially true in agriculture.Irrigation water that is not consumed by crops flows back into rivers or seeps into groundwater basins. Indeed, the single largest source of groundwater recharge in the Central Valley is irrigation. Studies from around the world consistently show that increased irrigation efficiency often does not decrease net water use. Indeed, these technologies often encourage farmers to plant more crops, worsening long-term declines in groundwater availability. The only way to generate reductions in water use on the scale imagined is to fallow several million acres of farmland.

In the urban environment, steady reductions in per capita water use since the early 1990s have allowed total urban use to remain steady at about 8.5 million acre-feet annually, despite the addition of 7 million new residents. Further savings — especially from more drought-tolerant landscapes — will be needed. But because about a third of urban water already gets reused — it also returns to rivers or groundwater basins — it’s simply not possible to achieve the level of new water that some have imagined.

The reality is that conservation is a valuable and necessary part of a portfolio of approaches to water supply management, but it will not produce vast quantities of new water for California.

As the late Sen. Daniel Patrick Moynihan said, “Everyone is entitled to his own opinion, but not to his own facts.” Californians need to make continued progress in managing our scarce water resources to get through this drought – and future droughts – while protecting the state’s economy, society and environment. This requires a common understanding of the causes of water scarcity, and practical, reasoned solutions — not blame games and wishful thinking.

Jay Lund is director of the UC Davis Center for Watershed Sciences and a professor of civil and environmental engineering. Jeffrey Mount and Ellen Hanak are senior fellows at PPIC.

On the numbers

By Jay Lund

Here are some of the calculations supporting the “environmental water” and water conservation impacts described in the above commentary.

Effects of environmental flow requirements on agricultural water use

Our standard here was pretty high. We looked for actual reductions in overall agricultural water use resulting from environmental flow requirements.

We have been unable to identify large reductions in urban and agricultural water use in most of California. In most areas, water use has remained about steady or increased slowly. While environmental requirements have often changed or disrupted water operations, raised operating costs or reduced expansions in water use, they usually have not caused major reductions in water delivered to end users of water.

The biggest delivery impact of environmental requirements is to users of water from the Sacramento-San Joaquin Delta. There,  the U.S. Endangered Species Act has caused actual long-term reductions in water supply, mostly for agricultural water users.

To keep things simple, we looked at overall water pumping from the state and federal water projects in the Delta. The results were surprising (Table 1). The largest amount ever exported directly from the Delta was almost 6.6 million acre-feet (maf) in 2011.

Table 1: Average Annual State and Federal Exports from Delta, Excluding Major Droughts (in millions of acre-feet). Source: California Department of Water Resources Dayflow data.

Period Total Delta exports Federal State
1978-1988 4.78 2.44 2.34
1992-2006 5.16 2.40 2.76
2007-2013 4.68 2.18 2.50
Maximum (2011) 6.56

In the era before the last big drought and endangered species listings (1978-1988), annual Delta exports averaged 4.8 maf. After the 1988-1992 drought, when more species became listed, annual average Delta exports increased to 5.3 maf. Following the Wanger decision of 2007 on biological opinions covering listed species, Delta exports decreased to 4.7 maf/yr, on average, not counting this drought water year.

Comparing this to average Delta direct exports from 1978-1988 — after the State Water Project came on line but before most endangered species listings — the longer-term reduction in water supply due to environmental flows is only about 0.1-0.2 maf/yr.

Compared with 2007-2013 export levels, this looks like about a 0.6 maf/yr average annual reduction in Delta water exports. (The baseline for comparison is clearly important.) Agriculture bore the brunt of these reductions, and farmers likely compensated for most of it by increasing groundwater pumping in the southern Central Valley (Chou 2012).

There also appears to have been some shifts in how water has been allocated, particularly with reductions in federal deliveries to agricultural contractors south of the Delta — the result of the Central Valley Project Improvement Act in late 1992. The law dedicated a project yield of 800,000 acre-feet a year (600,000 acre-feet in dry years) for the protection of salmon and other environmental purposes, with some of the environmental flows being reused by projects downstream.

Nevertheless, Westlands Water District and smaller west-side irrigation districts have seen large reductions in their federal water allocations from the Delta. At the same time, some State Water Project contractors including irrigators in southern Central Valley have seen growing water deliveries from the Delta and farmers selling water to cities and for environmental use (Hanak and Stryjewski 2012).

Most recently, the court settlement to restore salmon runs on the San Joaquin River is likely to further reduce water supplies to some agricultural water users. Allocations for instream flows will range from about 115 thousand acre-feet (taf) a year in critically dry years to 670 taf/yr in wet years, with the “normal” year range 360 taf/yr — 470 taf/yr (State Water Resources Control Board 2013). However, much of this water is to be available for recapture by downstream water users, including irrigators south of the Delta. Water allocations for the restoration efforts have been substantially curtailed during this drought year to minimize impacts to growers.

Adding up the numbers — and allowing for some urban impacts of post-Wanger cutbacks to the Delta and some substitutions of federal water project reductions with increased State Water Project exports following the Central Valley Project Improvement Act  — we estimate that agricultural water users south of the Delta experienced on average no more than a 1.5 maf/yr reduction in supplies because of environmental regulations.

This is not a trivial amount, but it is less than a 6 percent reduction for statewide agricultural water use. Many of the environmental requirements have shifted water allocations and increased costs rather than reduced net use of water.

Taking more water from the Delta would be less expensive than many alternative water supply and conservation actions. Increasing fluctuations in the amount of water available from the Delta are also a major reliability and cost concern. But did the environment ”take” this water, thereby reducing urban and agricultural water use, or just shift existing supplies from among water users? The answer seems to be all of the above.

How much “new water” does water conservation provide?

Water conservation does not always make more water available for use. Consider this example of washing a boat:

Last week I sailed from Vallejo to the Delta. While docked in Vallejo, I resisted the temptation to hose off the boat with fresh municipal water because the city is encouraging water conservation during the drought. By not washing the boat in Vallejo, about 20 gallons of fresh water became available for other urban uses rather than ending up in San Francisco Bay.

But then, while anchored off Mildred atoll, I washed the boat by heaving buckets of fresh water onto the deck. Almost all the water returned to the Delta for eventual use by farms or cities, or flowed out to San Francisco Bay. (I’m debating how much less evaporation occurred from the Delta because the surface area of my boat evaporates less than water surface area.)

Likewise, because water has further use downstream, water conservation in inland cities is less effective than water conserved in coastal cities. Switching from thirsty lawns to drought-tolerant plants frees up water for other uses.

To estimate the likely benefit of urban water conservation in California, former UC Davis graduate student Ryan Cahill and I recently examined the effect of reducing California’s per capita urban water use to levels common in Australia — some of the lowest in the world for prosperous economies with dry climates. We found it would reduce gross water use in California by about 2.1 maf/year and reduce net water use (making new water available for others) by about 1.5 maf/yr. This, again, is not a trivial amount. But it is less than 6 percent of the state’s agricultural water use.

In agriculture, most net water losses are to “evapotranspiration” – the amount of water consumed to grow crops. Almost all the excess water applied to fields already returns to recharge aquifers or supply rivers downstream where, in most cases, it is used again to grow crops or supply cities.

Improved plant breeding and farming has increased crop yields for decades, but has not greatly changed net water use per acre of agriculture. The large increases in agricultural “efficiency” often called for would mostly reduce aquifer recharge in wet years, jeopardizing water storage for dry years and not make much water available for other uses (Lund et al. 2011; Lin 2013). It is possible to reduce unproductive water losses from evaporation in fields, but only by a small amount and at a substantial management expense. Without reducing crop production — meaning fallowing land — surprisingly little net water can be saved from agriculture.

Further Reading

Cahill, R. and J.R. Lund, “Residential Water Conservation in Australia,” Journal of Water Resources Planning and Management, ASCE, Vol. 139, No. 1, Jan./Feb. 2013, pp. 117-121.

Chou, H., “Groundwater Overdraft in California’s Central Valley: Updated CALVIN Modeling Using Recent CVHM and C2VSIM Representations,” MS Thesis, UC Davis, 2012.

Hanak, E. and E. Stryjewski (2012) California’s Water Market, By the Numbers: Update 2012. Public Policy Institute of California, November 2012

Lin, C. (2013). “Paradox on the Plains: As water efficiency increases, so can water use. California WaterBlog, Aug. 13, 2013

Lund, J. and E. Hanak (2014) “Resistance is futile: Inevitable changes to water management in California.” California WaterBlog, Jan. 7, 2014

Lund, J., Hanak, E., Howitt, R., Dinar, A., Gray, B., Mount, J., Moyle, P., Thompson, B. (2011). “Taking agricultural conservation seriously.” California WaterBlog, March 15, 2011. (Lists references from the research literature on agricultural water use and conservation.)

State Water Resources Control Board (2013). Order Approving Change and Instream Flow Dedication (San Joaquin River), Sept. 28, 2012

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Could California weather a mega-drought?

Source: National Resource Conservation Administration

Source: National Resource Conservation Administration

By Jay Lund

In the past 1,200 years, California had two droughts lasting 120-200 years. Could the state’s water resources continue to supply enough water to drink, grow crops and provide habitat for fish with such an extreme, prolonged drought?

With careful management, California’s economy in many ways could withstand such a severe drought. That’s not to say some ecosystems and communities wouldn’t suffer catastrophic effects.

The UC Davis Center for Watershed Sciences explored this question a few years ago using computer models. We constructed a drought similar in scale to the two extreme ones found in California’s geological and biological records of the past 1,200 years (Harou, et al. 2010). We created a virtual 72-year-long drought with streamflow at 50 percent of current average rates, with all years being dry, as seen in the paleo-drought record.

We then explored the simulated drought using a computer model of California water management that suggests ways to minimize the economic costs of water scarcity for populations and land use in the year 2020.

Not surprisingly, the model results showed that such an extreme drought would severely burden the agriculture industry and fish and wildlife, and be catastrophic to some ecosystems and farm towns. The greatest impacts would be felt in the Central Valley.

However, if well managed, such a mega-drought would cause surprisingly little damage to California’s economy overall, with a statewide cost of only a few billion dollars a year out of a $1.9 trillion-a-year economy.

The key to surviving such a drought lies in adaptive strategies such as water trading and other forms of water reallocation. These strategies would be essential to improving the flexibility of California’s water supply and demand system during such a prolonged drought.

Interestingly, most reservoirs we have today would never fill during a decades-long drought, so expanding surface storage capacity would be futile.

California has a very flexible water supply system that can support a large population and economy under extreme adverse circumstances — provided it is well managed.

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

This article originally ran April 12, 2011. Some figures and text have been updated,

Further reading

Harou, J. J., J. Medellín‐Azuara, T. Zhu, S. K. Tanaka, J. R. Lund, S. Stine, M. A. Olivares, and M. W. Jenkins (2010), Economic consequences of optimized water management for a prolonged, severe drought in California, Water Resources Research46, W05522, doi:10.1029/2008WR007681.

MacDonald, G.M. (2007), Severe and sustained drought in southern California and the West: Present conditions and insights from the past on causes and impactsQuaternary International, 173-174: 87-100.

Stine, S. (1994), Extreme and persistent drought in California and Patagonia during medieval timeNature, 369, 546–549, doi:10.1038/369546a0.


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Modernizing California’s groundwater management

Senior Engineering Geologist Chris Bonds monitors production well flow rates during a visit to one of the 2013 groundwater susbstitution transfer projects.

State water engineer Chris Bonds checks  well flow rates at a “groundwater substitution transfer” project in 2013. Surface water becomes available for transfer to other water users by replacing that water with groundwater pumping. Photo by John Chacon, California Department of Water Resources

“A broad consensus appears to be building among California water users and policymakers that it is high time to establish an effective, statewide framework for groundwater management.”
— Groundwater Resources Association of California, Contemporary Groundwater Issues Council

As California strains under a third straight year of drought, Gov. Jerry Brown and many legislators have shown strong interest in modernizing management of groundwater – the state’s most important drought reserves. At the same time, a group of nearly 40 leading water professionals and scholars has been exploring ways California can move forward with more effective groundwater management. Organized by the Groundwater Resources Association of California, the Contemporary Groundwater Issues Council of scientists, economists, consultants, policymakers and regulators recently developed a set of consensus recommendations [1]. Council co-chairs Vicki Kretsinger Grabert, Thomas Harter and Tim Parker outline eight points that the group considers critical to moving California’s groundwater management into the 21st century.

Local management

1.  To further and support local groundwater management, the state should:

  • Identify local groundwater needs and problems at the basin or sub-basin level.
  • Identify local and regional areas in need of more formal groundwater governance structures.
  • Identify relevant local governance entities (such as water management agencies) and stakeholders, facilitate a process and timeline for developing local governance structure and identify a backstop if local management is ineffective.
  • Identify and develop financing mechanisms to support local management capacity.
  • Increase funding for state agencies to provide consistent technical support, quality assessment and backstop capability when local efforts are insufficient.
  • Facilitate development and implementation of local groundwater management plans.

Measurable basin management objectives

2.  To achieve groundwater sustainability, local basin plans’ management objectives should address:

  • Land subsidence
  • Ecosystem health
  • Surface-water flow depletions
  • Water quality, including salinity and seawater intrusion
  • Sustaining groundwater levels
  • Economic viability of pumping costs
  • Public health
  • Manageability of groundwater basin as a storage reservoir

3.  Water budgets should be established for each managed basin or sub-basin to define changes in storage and assess long-term drought and seasonal groundwater sustainability.

4.  Local and state agencies should ensure successful water budget development and document adverse impacts through comprehensive basin data collection, including:

  • Aquifer depth-specific groundwater levels
  • Aquifer depth-specific water quality measurements
  • Aquifer characterization
  • Consumptive use, including crop evapotranspiration
  • Metering of large pumpers and estimates of pumping by small pumpers
  • Precipitation
  • Stream gauging
  • Land subsidence

5.  To manage local groundwater sustainably, local or regional entities should:

  • Measure, assess and report on aquifer conditions
  • Review and recommend specific policy and management actions to meet basin management objectives
  • Develop mutually compatible objectives for sub-basins connected to neighboring sub-basins, with state water authorities acting as a backstop

Data management and information sharing

6.  State and local agencies should make data more accessible.

  • Data on pumping, well-drillers’ reports and other groundwater information can better inform analyses and computer models, which provide insights into better groundwater management
  • State constraints on data access are outdated and complicate data compilation

7.  Make groundwater data more transferrable.

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 

  • Coordinate access to data archives
  • Consolidate databases as appropriate
  • Develop easily accessible data houses [2] or web portals [3] linking multiple databases [such as the California Statewide Groundwater Elevation Monitoring (CASGEM) and Advisory Committee on Water Information] to build local capacity, maintain local control and link to other data
  • Front-end search engines can facilitate data searches
  • Databases should be available to local groundwater managers

8.  Develop minimum monitoring standards for groundwater levels, groundwater quality, water budgets, subsidence and reporting.

Groundwater resources in many areas of California are depleted to levels never before experienced in state history. At the same time, a broad consensus appears to be building among California water users and policymakers that it is high time to establish an effective, statewide framework for groundwater management.

Such a framework is needed to define and protect private groundwater-use rights and public interests in groundwater sustainability. Implementation of this framework will require strong local and regional leadership, clear mandates from the Legislature and secure funding.

Vicki Kretsinger Grabert is president of Luhdorff & Scalmanini, consulting engineers in Woodland. Thomas Harter is a groundwater specialist with the Cooperative Extension and the Center for Watershed Sciences at UC Davis. Tim Parker is president of Parker Groundwater, a groundwater consulting firm in Sacramento. The three are on the Groundwater Resources Association of California board of directors.

[1] The Groundwater Resources Association of California and the UC Davis Robert M. Hagan Endowed Chair hosted the meeting on May 13, following the release of recommendations on groundwater reform by the Association of California Water Agencies . The Center for Collaborative Policy at California State University, Sacramento, facilitated the discussion, which focused in three areas: (1) success stories and impediments for local groundwater management, (2) effective metrics for meeting basin management objectives at the local or state level and (3) data management and information sharing.

[2] Large databases include the USGS National Water Information System and those provided by the Consortium of Universities for the Advancement of Hydrologic Science.

[3] Web portals include the National Groundwater Monitoring Network, which links many states’ groundwater-monitoring databases.


Further reading

California Assembly Bill 1739 (Dickinson, 2014)

California Senate Bill 1168 (Pavley, 2014)

Lund, J.R. and Harter, T. (2013), California’s groundwater problems and prospects,, Jan. 30, 2013

Nelson, Rebecca (2011), Uncommon Innovation: Developments in Groundwater Management Planning in California, Water in the West Working Paper 1, Water in the West Program, Stanford University, California, 43 pp., March 2011

Recommendations for Achieving Groundwater Sustainability, Association of California Water Agencies, April 2014

Recommendations for Sustainable Groundwater Management: Developed through a Stakeholder Dialogue. California Water Foundation, May 2014



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Will California’s drought extend into 2015?

DWR’s Frank Gehrke of California’s Snow Surveys performs the last snow survey of the season.

Frank Gehrke found mostly bare ground here near Echo Summit on May 1, in the state’s final snow survey of the year. “Clearly it has been a very disappointing year in terms of any hope for water supply recovery coming off dry years last year and the year before,” Gehrke, the chief surveyor, told the Mountain Democrat newspaper of Placerville. “We’re very concerned now about next year.” Photo by Zack Cunningham/California Department of Water Resources

By Jay Lund and Jeffrey Mount

Debates over how to manage California’s critically dry water supplies this year have displaced most discussion about water next year.

This year’s drought is bad, but another dry year that begins with even lower groundwater and reservoir levels could be much worse. The state’s reservoir storage is already at near-record lows for this time of year, and accelerated overdraft of groundwater — the state’s most important drought reserves —  is likely to limit its availability.

How likely will next water year be dry?

What history tells us about next year

The historical record, imperfect and limited as it is, provides some information on the odds of water conditions improving or worsening.

California’s Department of Water Resources divides all water years (October to September) into five “year-types”: Critically Dry, Dry, Below Normal, Above Normal and Wet. This year the Central Valley is Critically Dry; last year was Dry and the year before that was Below Average.

Table 1 shows the percent of years from the historical record in each category, and the percent of years in each category if the previous year, like this one, was critically dry.

Based on 106 years of record, only 13 percent of years have been Critically Dry. But the odds facing California for next year aren’t as good. In the Sacramento Valley — the state’s largest source of water supply — there’s a 29 percent chance that the 2014-15 water year will also be Critically Dry, and a 64 percent chance that it will be Dry or Critically Dry — not favorable conditions for water management.

In all, there’s a 71 percent chance that next year will be Below Normal or drier and only a 29 percent chance of experiencing an Above Normal or Wet year.

Years with dry conditions (including critically dry, dry, and below normal years) are likely to be followed by dry conditions for three reasons. First, dry and wet patterns are driven by climate mechanisms that commonly extend over several years, often decades, making it more likely that any one year will be followed by one like it. Second, low moisture levels from a previous dry year will absorb some moisture in later years to reduce runoff. Third, a portion of the index used to define a water year depends on precipitation from the previous year, which increases the likelihood that the following year will be like the previous.

Years with dry conditions (critically dry, dry and below normal years) are likely to be followed by dry conditions for three reasons. First, dry and wet patterns are driven by climate mechanisms that commonly extend over several years, often decades, making it more likely that any one year will be followed by one like it. Second, low moisture levels from a previous dry year will absorb some moisture in later years to reduce runoff. Third, a portion of the California Department of Water Resources index used to define a water year depends on precipitation from the previous year, which increases the likelihood that the following year will be like the previous. Even when annual flow data alone are used — eliminating the DWR index’s dependence on the previous year — critically dry years are more than twice as likely to occur if preceded by a critically dry year.

What about El Niño?

The news abounds with hopeful statements about Pacific winds and sea surface temperatures heralding an El Niño. The periodic shift of warm water from the Western to the Eastern Pacific [known as the El Niño Southern Oscillation (ENSO)] is linked to weather extremes over much of the globe.

Meteorologists have long noted that intense El Niño events are commonly associated with high precipitation in Southern California. Though, historically, odds are against improved water conditions next year, an El Niño could end California’s drought.

The relationship between the ENSO index and annual runoff in the Sacramento and San Joaquin river basins since 1950 is plotted in Figure 1. Although ENSO may signal significant weather changes elsewhere in the world, it has little predictive capacity in Northern California where most of the state’s precipitation occurs. (It has better predictive value for Southern California).

Note in Figure 1 that three of the four largest ENSO events are associated with very wet conditions. Two of these – water years 1983 and 1998 – were record-breaking wet years. This seems to offer a glimmer of hope. But the numerous dynamic and statistical models that predict ENSO conditions into the new water year have positive, but disappointingly weak ENSO values. An El Niño may turn out to be closer to La Nada if the projections of these models bear out.

ENSO index plotted here is average of December-April for each water year

ENSO index plotted here is average of December-April for each water year

Hope is not a strategy

During a severe drought, water managers and regulators must balance water deliveries in the current year against saving water for unknown conditions in coming years. It is statistically likely the drought will continue into next year. We all hope wet weather returns to California soon. But, given the odds, it makes sense to prepare for another dry year.

Jay Lund is a professor of civil and environmental engineering and director of the Center for Watershed Sciences at UC Davis. Jeffrey Mount, a UC Davis professor emeritus of geology, is a senior fellow at the Public Policy Institute of California.

Further reading

Ault, T., George, S., 2010. The Magnitude of Decadal and Multidecadal Variability in North American Precipitation. Journal of Climate, p. 842-850

Hidalgo, G. H., 2004: Climate precursors of multidecadal drought variability in the western United States. Water Resour. Res., 40, W12504, doi:10.1029/2004WR003350

Klemes, V., 2000: Drought prediction: A hydrological perspective. Common Sense and Other Heresies: Selected Papers on Hydrology and Water Resources Engineering, Canadian Water Resources Association, 163–176

Reynolds, R., Dettinger, M., Cayan, D., Stephens, D., Highland, L. Wilson, R., 1997. Effects of El Niño on Streamflow, Lake Level and Landslide Potential, U.S. Geological Survey

El Niño/La Niña Resource Page, Golden Gate Weather Services, May 2014 

Impacts of El Niño and benefits of El Niño Prediction, National Oceanic and Atmospheric Administration 

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Should California expand reservoir capacity by removing sediment?


Shasta Reservoir. Source: California Department of Water Resources

By Jay Lund

Removing sediment from reservoirs is often suggested as a potentially better way to expand storage capacity than raising dam heights or building new reservoirs. This is a natural notion to explore given the cost and likely environmental impacts of traditional expansions.

For perspective, the construction cost of conventional reservoir expansion is about $1,700 to $2,700 an acre-foot (af) of storage capacity. For example:

The cost of expanding reservoir capacity by removing sediment seems likely to be $5 to $20 a cubic yard or $8,000 to $32,000/af (at 1,600 cubic yards/acre-ft).

dredging buckets

Clamshell dredge buckets like these are used to remove sediment from reservoirs and harbors. Source: Flickr Commons

At these high costs, removing sediment would be done only rarely, in small quantities, for very valuable purposes when other alternatives are unavailable. For example, sometimes sediment that has accumulated behind flood and debris control dams in Southern California is removed for maintenance. But these are usually small dams built to protect homes and businesses from floods with enormous sediment loads.

Sometimes sediment can be removed by releasing it through low elevation dam outlets when the reservoir is very low. This method, known as sluicing, can sometimes be done for small reservoirs. For larger reservoirs, sluicing is limited by two factors: a) the large amount of water that must be released to remove sediment and b) the tendency for most sediment to deposit at the inflow of the reservoir, far up and away from the dam, making it hard to sluice.

San Luis Reservoir during the drought in California, February 5, 2014. Photo by Florence Low/California Department of Water Resources

San Luis Reservoir during the drought in California, February 5, 2014. Photo by Florence Low/California Department of Water Resources

Removing sediment must become more economical to be cost competitive with traditional reservoir expansion. The current cost gap is rather large.

It should be noted that most of the largest dams in California have relatively little sediment because their watersheds yield relatively little of it. One study estimates about 1.7 maf of sediment across 1,200 dams in the state (Minear andKondolf 2009). The scientists estimate that sedimentation could eliminate 15 percent of California’s reservoir capacity within 200 years. Most major reservoirs would see little gain from the high expensive of removing the material.

Source: Los Angeles County department of Public Works

Big Tujunga Reservoir in the San Gabriel Mountains controls floods and debris flows. Source: Los Angeles County Department of Public Works

Of course, a few of the 1,400 reservoirs in California might be worth expanding by sediment removal (and some reservoirs might be worth removing entirely). But these projects are likely to be so small and rare as to not have a major statewide benefit, and can probably be financed locally.

Finally, reservoir capacity is not the same as water deliveries from a reservoir. Reservoirs do not create water; they only deliver water stored from some previous time.

A reservoir expansion in California today is expected to yield on average only 7 percent to 14 percent of its additional capacity annually.

Storage should always be looked at as a component of a larger water management portfolio.

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

Further reading

Lund, J (2011), “Water storage in California,”, Posted Sept. 13, 2011

Lund, J (2012), “Expanding water storage capacity in California,”, Posted Feb. 22, 2012

Minear, J. T., and G. M. Kondolf (2009), “Estimating reservoir sedimentation rates at large spatial and temporal scales: A case study of California,” Water Resources Research, 45, W12502, doi:10.1029/2007WR006703

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