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April 16, 2013

Central Valley Agriculture and the Delta Smelt Today

Filed under: Uncategorized — admin @ 10:08 pm

The Delta Smelt is a small endemic fish of the Sacramento-San Joaquin estuary.  Maturity is reached when the fish are 55-70 mm in length and most die after a year.  They mainly live in areas where salt and fresh water mix and they can find an abundance of zooplankton to feed on.  Spawning, however, occurs in fresh water areas just upstream of the mixing zone.  These little fish are very susceptible to changes in population size because of their short life cycle (1 year) and their low fecundity.  Because of these two factors, environmental changes have a great impact on the survival of the species.  When there is sufficient water in the estuary, the mixing zone moves into the Suisun Bay, which lies to the west of the Sacramento-San Joaquin river delta.  This is better for the fish because the zone expands over a larger area and there are more available food sources for the fish (Moyle, 1992).  When water is diverted for agricultural use, the water level is lowered and mixing occurs in the narrow delta channels, an ill suited habitat for delta smelt spawning (Moyle, 1992).  There have been declines in the population of this endemic species since the 1980s, and many blame the increasing diversion of estuary water for irrigation (Moyle, 1992).

In an effort to stabilize the species, the delta smelt has been categorized as an endangered species, and therefore is under the protection of the Endangered Species Act.  This act limits the amount of water that can be pumped from the delta waters, especially during the spawning period, March through May.  The impacts of this protection burden the Central Valley farmers who rely heavily on the waters from the estuary to irrigate their fields.

The Central Valley, one of California’s most productive agricultural areas, relies on this irrigation water because of the lack of natural rainfall that actually occurs in the area. Originally, the Central Valley farmers relied on an underground aquifer to irrigate their croplands, leaving the estuary undisturbed. When agriculture expansion occurred, however, water had to be diverted from the Sacramento-San Joaquin delta region in order to decrease pressure on the aquifer. In 2007, limits were imposed on the amount of water that could be pumped from the delta in order to protect the endangered delta smelt, forcing the irrigation pumps to be shut off. Without access to freshwater from the north, the land in the Central Valley becomes arid and unsuitable for agricultural use.  This loss of agricultural land has left thousands in the Central Valley without jobs (Howitt et al., 2009).

Central Valley farmers have been pressuring politicians to return their irrigation water, outraged at the prospect of losing their livelihoods to save a tiny, seemingly insignificant fish. The H.R.1837 bill, with the promise of turning the irrigation pumps back on, offered a positive outlook for struggling farmers when it passed House in 2012 (H.R. 1837, 2011). This hope, however, was snuffed out with its failure to pass in the Senate, and a promised veto from President Obama should it pass (Statement of Administration Policy, 2012). With little progress made in the way of protection of the delta, it is not likely that the restrictions will be lifted any time soon. By February of 2013, 232 delta smelt were killed as a result of pumping stations approaching the annual limit of 302 allowed by the Endangered Species Act at a dangerously high rate (Quinton, 2013).

As of now, the pumps remain off but tensions remain high. With these two opposing needs in mind, the California Department of Water Resources has suggested a new system that aims to appease both parties; a $14 billion twin tunnel system. This project would channel the water from beneath the delta to pumping stations in Tracy, California, which lies South of the Delta (Woodard, 2012). Though the proposal offers benefits for both conservation and irrigation, many are opposed to its large price tag (Woodard, 2012). Until a better solution is found, it is not likely that restrictions will be lifted.

Map of the Delta

This post was authored by Alice Bitzer and Jana Matsuuchi



Howitt, Richard, Josue Medellin-Azuara, Duncan MacEwan. “Measuring the

Employment Impact of Water Reductions” Department of Agriculture and

Resource Economics and Center for Watershed Sciences, UC Davis (2009): 1-10.

“H.R. 1837–112th Congress: Sacramento-San Joaquin Valley Water Reliability Act.” 2011.

Moyle, Peter B., Bruce Herbold, Donald E. Stevens, and Lee W. Miller. “Life History

and Status of Delta Smelt in the Sacramento-San Joaquin Estuary, California.”

Transactions of the American Fisheries Society 121.1 (1992): 67-77. Print.

Quinton, Amy. “Delta Smelt Deaths Means Less Water for Central and

Southern California.” KPBS. Capital Public Radio, Feb. 2013. Web. Mar. 2013.

Statement of Administration Policy: H.R. 1837 – Sacramento-San Joaquin Valley Water

Reliability Act (2012) (testimony of Rep. Nunes, R-California, and 2 Cosponsors).

Woodard, Niki. “California Water: The Muddy Issue of the Delta Twin

Tunnels.”California Forward. N.p., Aug. 2012. Web. Mar. 2013.


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