We asked some colleagues for lessons that might be useful in managing the California’s new drought. Here is a first sampling of thoughts.

1: Market-based approaches to water management will lessen the costs of drought. Katrina Jessoe. Agricultural and Resource Economics, UC Davis

Climate models indicate that California’s droughts will become more frequent and severe. Warming temperatures will further reduce surface water availability, by increasing evaporation from soil, reservoirs, and irrigated land. While reductions in surface water supplies will be costly to agriculture, residential users and the environment, these costs could be substantially reduced through the reallocation of scarce supplies. Supplying water to those who value it most will not eliminate the costs of drought, but will make them less painful. 

Policymakers and utilities have three pragmatic economic instruments to mitigate the cost of this drought. First, establishing well-defined rights for groundwater and surface water would reduce groundwater extraction, and foster water transfers among and across user groups. Second, water transfers among agricultural, urban and environmental users or between these groups would move water from lower value to higher value uses. While transfers have occurred since the 1976-77 drought, high transaction costs deter wider scale deployment. The state could help broker transactions and reduce the red tape involved with them. Third, water should be priced to reflect the cost of supplying and/or extracting it. This is particularly relevant for groundwater, since agricultural groundwater is rarely priced. Prices would reflect the cost of extraction on other agricultural pumping costs, groundwater quality, and the availability of future groundwater supplies. Revenues could fund alternative water supplies, such as recycled water deliveries and artificial groundwater replenishment. This would improve the long-run availability of groundwater resources, and their ability to act as a critical buffer to surface water reductions during droughts. 

Further reading –

Bruno, E. M., & Jessoe, K. (2021). “Missing markets: Evidence on agricultural groundwater demand from volumetric pricing.” Journal of Public Economics, 196, 104374.

Bruno, E. M., & Jessoe, K. (forthcoming). “Using Price Elasticities of Water Demand to Inform Policy.” Annual Review of Resource Economics.

Leonard, B., Costello, C., & Libecap, G. D. (2019). “Expanding water markets in the western United States: barriers and lessons from other natural resource markets.” Review of Environmental Economics and Policy, 13(1), 43-61.

2: Central Valley agriculture is the most vulnerable economic sector to drought, and has long relied on a large chronic overdraft of groundwater. Josue Medellin-Azuara, Civil and Environmental Engineering, UC Merced

Shortly after the 2012-2016 drought, followed by the bonanza of several unusually wet or not too dry years, groundwater sustainability plans (GSPs) from the recently established groundwater sustainability agencies were submitted as the locally-driven pledge to attain balance in recharge and extraction by 2040. This drought will become the acid test for the effectiveness and resilience of agriculture in adhering to such plans in the early stages of Sustainable Groundwater Management Act (SGMA) implementation. Unlike historical droughts, agriculture is now required to adhere to the GSP guidelines for pumping in dry years. As the drought progresses, other systemwide vulnerabilities lingering from the recent droughts in the Valley such as small rural water systems on shallow wells, groundwater dependent ecosystems and infrastructure damage will likely resurge in some new forms. This gives the state and stakeholders opportunities to revisit GSPs water portfolios and procedure effectiveness  in order to address this multi-objective problem. The current drought also will unveil or affirm areas in which the state is making some slow progress such as developing and organizing open access data and modeling platforms to inform management decisions, a wide adoption of low environmental impact water exchanges, managed recharge, and more participative management of small water systems and communities. 

Further reading –

Cantor, A., Owen, D., Harter, T., Green Nylen, N., & Kiparsky, M. (2018). Navigating Groundwater-Surface Water Interactions under the Sustainable Groundwater Management Act. UC Berkeley: Berkeley Law. Retrieved from https://escholarship.org/uc/item/720033b2 

Hanak, E., Escriva-Bou, A., Gray, B., Green, S., Harter, T., Jezdimirovic, J., Lund, J., Medellín-Azuara, J., Moyle, P., & Seavy, N. (2019). Water and the future of the San Joaquin Valley. Public Policy Institute of California: San Francisco, CA, USA.

Jasechko, S., & Perrone, D. (2020). California’s Central Valley Groundwater Wells Run Dry During Recent Drought. Earth’s Future, 8(4), e2019EF001339. https://doi.org/https://doi.org/10.1029/2019EF001339

Lund, J., Medellin-Azuara, J., Durand, J., & Stone, K. (2018). Lessons from California’s 2012–2016 drought. Journal of Water Resources Planning and Management, 144(10), 4018067. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000984 

3:  Native fishes like Chinook salmon, splittail, and Delta smelt are adapted to persist and even thrive  through severe droughts, but  they are not well adapted to persist through modern droughts.  Peter Moyle, Wildlife, Fish, and Conservation Biology, UC Davis 

The well-honed drought survival strategies of California’s native fishes  don’t work very well in contemporary California, as seen by their  rapid decline through recent droughts. Dams block access to most cold water spawning and rearing areas once used by salmon and steelhead.  Dams also fragment native fish populations so re-colonization of once-dry streams is not possible. Reservoirs cover the deep pool refuges present in the rivers and support mostly non-native fishes which exclude native fishes, especially through predation. Flow below dams can create good conditions for native fishes during drought, but can be abruptly shut off, becoming ecological traps rather than refuges. Low or no inflow to estuaries can make them too salty or warm, even for tolerant natives.  

In general, drought in California reduces native fish populations and, where there is water, favors non-native fishes more tolerant of changed habitat and flow conditions. 

So how do we save our fishes from the effects of extended drought?  The answer lies in a combination of creative thinking and assured water supplies for fish refuges.  Basically, extended drought creates a need for more frequent, rapid, and flexible actions to save fish.  Better monitoring of all native fishes is needed to start. This monitoring should include an evaluation of every species status at least once every five years, including identification of drought refuges.  During droughts, fishes with small and/or fragmented populations should be evaluated annually and action taken to prevent loss of isolated populations, such as moving fish to more secure habitats or moving water to the refuges. Some especially vulnerable fishes include Red Hills roach, Northern roach, Long Valley speckled dace, McCloud River redband trout, and Klamath River summer steelhead.  Without an active program of evaluation and intervention, these native fishes will decline to extinction, drought by drought. 

Further reading – 

Mount, J., B. Gray, K. Bork, J. E. Cloern, F. W. Davis, T. Grantham, L. Grenier, J. Harder, Y. Kuwayama, P. Moyle, M. W. Schwartz, A. Whipple, and S. Yarnell. 2019.  A Path Forward for California’s Freshwater Ecosystems.  San Francisco: Public Policy Institute of California. 32 pp. https://www.ppic.org/wp-content/uploads/a-path-forward-for-californias-freshwater-ecosystems.pdf

Lennox R.J., D.A. Crook, P. B.  Moyle, D. P. Struthers, and S. J. Cooke 2019. Toward a better understanding of freshwater fish responses to an increasingly drought-stricken world. Reviews in Fish Biology and Fisheries 29:71-92  https://doi.org/10.1007/s11160-018-09545-9.  Open Access.

Howard, J.K, K. A. Fesenmyer, T. E. Grantham, J. H. Viers, P. R. Ode, P. B. Moyle, S. J. Kupferburg, J. L. Furnish, A. Rehn, J. Slusark, R. D. Mazor, N. R. Santos, R. A. Peek, and A. N. Wright. 2018. A freshwater conservation blueprint for California: prioritizing watersheds for freshwater biodiversity.  Freshwater Science 37(2):417-431. https://doi.org/10.1086/697996

Moyle, P.B., J. D. Kiernan, P. K. Crain, and R. M. Quiñones. 2013. Climate change vulnerability of native and alien freshwater fishes of California: a systematic assessment approach. PLoS One. http://dx.plos.org/10.1371/journal.pone.0063883

4: Environmental flows and temperature mitigation are critical to ecosystems during droughts, and difficult to achieve. John Durand, Center for Watershed Sciences, UC Davis

The recent 2012-16 drought seriously degraded environmental conditions in the Sacramento River and Delta. At that time, a coordinated approach by the Real-Time Drought Operations Team, with representatives from water, fish and wildlife management agencies, was extremely helpful in managing some of the worst effects of the drought.  

Current reservoir levels show we are back where we were in 2014 and 2015. Having little stored water then had implications for water supply and quality, as well as environmental conditions. Decreased flows increased salinity in the Delta, which jeopardized local agriculture and urban water supplies, as well as contaminating water exports from the south Delta. To minimize these risks, a temporary salinity barrier was installed at False River, near Franks Tract in 2015, which proved effective. The rapid deployment of such a barrier might provide some  control in the current situation, and help to maintain fresh water for agricultural and urban use, with less disruption to the Delta ecosystem.The barrier also helped to preserve water storage north of the Delta, in case it would be needed in future years for environmental or human uses.

Preserving stored water also is important for stream temperature management. The last drought was  extremely hot. Both winter and summer temperatures were high for extended periods of time. This jeopardized the cold water pool in Shasta Reservoir, which is needed to maintain the last spawning grounds of winter-run Chinook salmon (their original cold-water spawning grounds, high in the Cascades, are now blocked by Shasta dam). Nearly two-thirds of the entire wild population was lost when temperatures rose uncontrollably in 2014 and 2015, leading to nearly complete recruitment failures in both years. This situation is likely to recur without a serious effort by the US Bureau of Reclamation to reserve sufficient water in the reservoir to last through a hot summer season. Hatchery support will be needed if we face catastrophically high temperatures again–but once a species goes into hatchery support, it becomes harder to restore to the wild ever again.  

This is also true of Delta Smelt, which mostly disappeared in the last drought. Efforts are being made to support the population using hatchery stock, but Delta conditions are likely to continue to degrade in ways that frustrate this effort, especially during a drought. The combination of low, slow flows, increased water clarity,  and warmer temperatures stress native fish populations and encourage the growth of invasive aquatic weeds. During the last drought, aquatic vegetation transformed parts of the north Delta to resemble the south Delta: warm, slow-moving water clogged with weeds. The weeds themselves exacerbate these conditions, leading to self-sustaining feedbacks that preclude conditions that support Delta Smelt and other native fishes: too-warm water, degraded spawning habitat, and limited pelagic food. 

Actions to support native fishes and habitats are best implemented during non-drought conditions, which allows restoration, planning, and stock enhancement to occur. At this point in the ongoing drought, we can invoke emergency mitigation measures to try to counter the worst effects of low flows and high temperatures. But this drought is coming hard on the heels of the last drought. From the perspective of history, it may well be an extension of the last, or a harbinger of conditions that will become chronic, as predicted by most climate change models. 

Further reading:  John R. Durand, Fabian Bombardelli, William E. Fleenor, Yumiko Henneberry, Jon Herman, Carson Jeffres, Michelle Leinfelder–Miles, Jay R. Lund, Robert Lusardi, Amber D. Manfree, Josué Medellín–Azuara, Brett Milligan, Peter B. Moyle. Drought and the Sacramento–San Joaquin Delta, 2012–2016: Environmental Review and Lessons. San Francisco Estuary and Watershed Science, 18(2). 

5: Successful cold-water management requires major changes to dam regulation. Ann Willis, Center for Watershed Sciences, UC Davis

Streams and lakes with cold-water thermal regimes support native ecosystems throughout California. Given our extensive investment in cold-water management through dam regulation, California appears well-positioned to sustain cold-water habitat. But when we look at differences between regulated and unregulated stream temperature patterns, managed streams are a lukewarm substitute. Historical headwater habitats show distinctive thermal regimes compared to currently accessible, dam-regulated reaches. Although dam regulation has done a reasonably good job at mimicking desirable summer temperatures, the predominant focus on managing summer stream temperatures has overlooked the problem of increasing winter stream temperatures. California’s dams generally appear incapable of replicating stable cold-water regimes, with the possible exception of Shasta Dam, which will be severely tested this year. But when only one of scores of dams throughout the state shows promising results for environmental stream temperature management, we must question whether this approach is truly viable. 

Maintaining stream temperatures for cold-water ecosystems prompts great concern. Every drought renews temptation to feed our addiction to infrastructure. Stream temperature research shows that we cannot build our way to a sustainable future through regulation. California has to confront the incompatibility of near-ubiquitous dam regulation of its streams and the desire to restore and sustain cold-water ecosystems. Difficult decisions about dam removal versus species extinction and the collapse of cold-water ecosystems lay ahead.

Further reading – Willis, Ann. 2020. Keeping it Cool: Sustainable Stream Conservation Using Process-Based Thermal Regime Management. Doctoral dissertation.