Rapid changes in the Sacramento-San Joaquin Delta both diminish scientific certainty and increase science’s value

Hump of hope

(source: Jessica Hagy) Change and discomfort can lead to improvement; too much discomfort leads to panic.

by Jay Lund

Conditions in the Sacramento-San Joaquin Delta are changing, changing in new ways, and changing rapidly.  Changes are rampant not only in climate, but also in ecosystem structure, economic structure and globalization, invasive species, infrastructure, water demands, environmental regulations, and societal objectives.  Although the Delta always has  changed, often rapidly, we are seeing new types of changes.

Major ongoing and expected changes for the Delta will be driven by:

  • Climate change, particularly rising temperatures and sea level
  • Continued species invasions
  • Worsening struggles for native and listed species
  • Continued Delta land subsidence, perhaps accelerated by higher temperatures
  • Greater economic demands for Delta water exports from implementing the Sustainable Groundwater Management Act
  • Growing water quality concerns for urban and agricultural water uses
  • Rising costs for levee maintenance, rehabilitation, and repair of failures
  • Frustration with the seeming ineffectiveness of traditional environmental regulations
  • Rising concern with inequalities in wealth and opportunities

These changes will be substantial, multi-faceted, and often rapid.  Some changes will be irreversible.  Many changes are inevitable.  Some will say today’s Delta is doomed.

It will be important for California to develop a scientific program that can help guide difficult policy and management discussions and decision-making through these challenges.  Changes in the organizational structure of policy and management also may be needed.  Even though some aspects of the Delta are doomed to change, many aspects will endure, and others will thrive differently, particularly if policy and management decisions adapt well. The Delta of the future will be different, and different sorts of science and management may be needed.

Managing with rapid changes

California has always had to manage with rapid changes in climate (with its wet and dry seasons and extreme variability between floods and droughts), population, economic structure (from mining to agriculture, to industry, to post-industrial within 150 years), and prevailing political philosophy (decentralization to centralization and back again).  Managing with such changes has made California unusually successful, but not without awkwardness, environmental and economic damage, and often prolonged dithering, delays, and controversy.

Although not all changes can be managed, a wide range of responses can help.  Options range from infrastructure (levees, conveyance, barriers, habitat development, channel changes), operations (export pumping, operable and emergency barriers, upstream water operations, and land uses), new approaches to environmental management (such as those proposed by the SWRCB and being negotiated), and changing (often reducing) demands for water and land, and environmental and land use expectations.

These actions should be viewed within a portfolio of activities organized to better manage the Delta.  No portfolio of actions will be perfect.  Even the best responses will have major costs to various interests, balanced and allocated somewhat by government.  We are not doomed with change, but we are in trouble.

Better organization and information can reduce overall costs and better inform their allocation.

Science for managing with rapid changes

Given rapidly-changing conditions, science is both more important and more challenged.

For rapidly changing conditions,

  • Ecological science, which traditionally had focused on equilibrium relationships among species and static environmental conditions, may be unable to respond to management needs through reliance on traditional long-term observations and experiments.
  • Social sciences, relying predominantly on collections of past and present data, must deal with rapid changes in demography, economic structure, and societal objectives in real time to give advice for changing times in the future.
  • Engineering must design and prepare for a wider range of conditions and societal expectations, which will change with time.
  • Physical sciences must develop insights with changing and uncertain boundary conditions and interactions with changes in ecological, engineering, and social conditions.

Most people seem both impressed and disappointed with today’s ability of science to provide insights into the Delta’s problems and solutions.  Science will be hard pressed to keep up with changes and help policy-makers, managers, and the public keep ahead of such changes.

Managing with inadequate management and science

Even if science cannot keep up with changes in conditions, the value of well-employed science increases when it helps make policy and management decisions better than they would be otherwise.  Effort is needed to make the organization and resources of science for the Delta’s problems more forward-looking and useful across the many agencies and interests which make Delta decisions.

Uncertainties and changing conditions make adaptive management both more difficult and more necessary.  Adaptive management requires an ongoing effort for scientific synthesis, usually using computer models, to more explicitly and rapidly integrate new knowledge into a logical science-based framework, so that it can be applied to develop insights for policy and management.

There will be failures.  But our use of science will be more successful if we develop effective organization and resources to respond to and learn from failures, rather than delay in hopes of developing and implementing a perfect plan.  Preparing for the likelihood of failures involves establishing farsighted policies for responding when species are becoming extinct, subsided lands flood, and salinity intrudes during drought – responding in ways that strategically improve long-term Delta conditions.  Despite our best efforts, artfully failing into solutions may be more promising and feasible than the technical and political development of ideal plans for responding to change.


The Delta is changing and will inevitably change in important ways that will affect all of California.

Science will become more important for managing the Delta, even as knowledge becomes less perfect due to rapid changes in conditions.  Without well-organized forward-looking science, management decisions and actions are likely to be still more imperfect.

Rapidly changing conditions for the Sacramento-San Joaquin Delta challenge both our organization and objectives for Delta science and management.  We must prepare for a changing Delta future, and for our limited ability to understand and manage.  (Otherwise, discomfort can become excessive.)

Further reading

Arax, M. (2019), The Dreamt Land: Chasing water and dust across California, Knopf, 527pp.

Berbela, J. and E. Esteban (2019), “Droughts as a catalyst for water policy change. Analysis of Spain, Australia (MDB), and California,” Global Environmental Change, Vol. 58, 101969.

Hollings, C.S. (ed.) (1978), Adaptive Environmental Assessment and Management, London:  John Wiley and Sons.

Kelley, R. (1989), Battling the Inland Sea, UC Press, Berkeley, CA.

Lund, J.R., J. Medellín-Azuara, J. Durand, and K. Stone (2018), “Lessons from California’s 2012-2016 drought,” J. Water Resour. Plan. Manag. 144 (10), 04018067.

Madani, K. (2019), “The Value of Extreme Events: What Doesn’t Exterminate Your Water System Makes it More Resilient,” Journal of Hydrology, Vol. 575, 269-272

Pinter, N., J. Lund, and P. Moyle. “The California Water Model: Resilience through Failure,” Hydrological Processes, Vol. 22, Iss. 12, pp. 1775-1779, 2019.

Wiens, J., et al. (2017), “Facilitating Adaptive Management in California’s Sacramento–San Joaquin Delta,” San Francisco Estuary and Watershed Sciences, Vol. 15, No. 2, July, 15 pp.

Jay Lund is a professor of Civil and Environmental Engineering at the University of California – Davis.

About jaylund

Professor of Civil and Environmental Engineering Director, Center for Watershed Sciences University of California - Davis
This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply