Posted by: Deirdre Des Jardins | May 1, 2021

The “greedy” strategy for SWP and CVP reservoir operations

Current operations of the State Water Project and Central Valley Project reservoirs in the Sacramento Valley are an example of a greedy strategy.[1] Under the greedy strategy, the system operators export as much water as possible in any given year. The strategy results in maximum water deliveries in a given year, but with the risk of catastrophic shortages in droughts.

The risks of the greedy strategy have little impact on Southern California urban water agencies who have developed millions of acre-feet of South of Delta storage. But the strategy does create major shortages and costs for South of Delta agricultural water users who don’t have multiyear storage.

The greedy strategy also has devastating impacts on in-basin beneficial uses. The greedy strategy was disastrous for salmon and native fish in the 2012-2016 drought, and will be disastrous again in 2021. Draining Northern California reservoirs also impacts all other beneficial uses in the Sacramento Valley and the Delta, including agricultural and urban water users, wildlife refuges, and water quality in the Delta.

Metropolitan Water District, storage, April 26, 2021 [2]

The greedy strategy is contrary to studies of optimal reservoir management for drought and climate change. Aris Georgakakos has studied forecast-informed reservoir operations for the SWP and CVP.  While he’s best known for the INFORM system for operating the SWP and CVP for floods, he’s also studied operating reservoirs for droughts. Georgakakos’ studies have pointed to the need for major changes in SWP and CVP operations for climate change. In 2012, Georgakakos et. al. wrote:

The assessments show that the current policy, which is tuned to the historical hydrologic regime, is unable to cope effectively with the more variable future climate. As a result, the water supply, energy, and environmental water uses cannot be effectively satisfied during future droughts, exposing the system to higher vulnerabilities and risks. By contrast, the adaptive policy maintains similar performance under both hydrologic scenarios, suggesting that adaptive management constitutes an effective mitigation measure to climate change. [3]


1, Moore, J. Khim, and E. Ross, Greedy Algorithms, Math & Science Wiki,

2. Metropolitan Water District, Water Supply Conditions Report, April 26, 2021

3. A.P. Georgakakos, H. Yao, M. Kistenmacher, K.P. Georgakakos, N.E. Graham, F.-Y. Cheng, C. Spencer, E. Shamir, Value of adaptive water resources management in Northern California under climatic variability and change: Reservoir management, Journal of Hydrology, Volumes 412–413, 2012, Pages 34-46, ISSN 0022-1694


  1. “The Greedy Strategy” has the ring of truth to it. Greed is defined as an excessive or reprehensible behavior. These adjectives describe people who take water needed to keep endangered animals from being able to survive. People who exhibit this kind of greed are worthy of strong disapproval by society, yet they are often powerful enough to escape it.

  2. Greed seems like the wrong word. I would associate self-interest with a cautious risk designed to provide the least harm. What they are doing is running the greater risk of running out. That may be “I’ll get mine first, and be gone when ..,” but it is not traditional conservative risk avoidance.

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