By Scott Hamilton, President, Hamilton Resource Economics

Environmentally, the San Joaquin Valley is very different from what it was 170 years ago. And during that time, the Valley landscape has been evolving. The Valley floor originally consisted of a number of diverse ecosystems: grasslands, oak woodlands, alkali desert scrub, wetlands, a number of lakes, and riparian habitats. The period of the early Mexican ranchos (1830s-1850s) was an era dominated by cattle grazing. By the late 1800s, the Valley was transformed into fields of wheat, barley and hay. Beginning in the 1950s cotton became dominant, and while fruit had always been present, vineyard and tree crops acreage expanded greatly since 1990. As a result, major changes to the valley ecosystems occurred, particularly with the construction of large dams on the eastside rivers in the mid 1900s. Before the construction of those dams, the rivers expanded and contracted with the seasons supporting a variety of ephemeral and unique habitats, hundreds of miles of riparian habitat and millions of acres of wetlands. The development of a vast water infrastructure has supported expansive agricultural and urban development and caused the repurposing of large swaths of natural lands.

The conversion of row crop land to orchards and vineyards required nearly double the water use and resulted in an unsustainable level of groundwater pumping. That led to the advent of the Sustainable Groundwater Management Act (SGMA) passed by the California legislature in 2014. The Act mandates groundwater sustainability by 2040 for most of the Valley.

As water district managers scramble to capture every last drop of water, the reality has set in that there is simply not enough water available in the Valley to sustain the current level of agricultural production. The Water Blueprint for the San Joaquin Valley ( is working to bring additional sources of water into the Valley to sustain communities, agriculture and the environment, but the new sources of water will not be cheap, and land conversion will be needed to increase the capacity to recharge aquifers. It is inevitable that some agricultural land will come out of production. How much is not yet clear, but the number will certainly be in the tens of thousands, and maybe hundreds of thousands of acres.

Dr Huber’s Core Areas and Connecting Corridors
FIGURE 1. Dr Huber’s Core Areas and Connecting Corridors (Conservation Biology Institute, 2020)

A number of efforts are underway to facilitate that process and minimize the ensuing hardship, primarily by buying land at fair market value from willing sellers. But then what will happen to that land? SGMA necessarily will create a major transition in the Valley. Within that transition is an opportunity.

Without some organized plan, land fallowing that occurs randomly could result in increased dust, weeds and pests with little ecological benefit. But with thoughtful planning and the right structure, it is possible to develop an environmental vision for the Valley–one that restores lost ecosystems, adds biodiversity and makes the Valley a better place for animals and people alike. A number of organizations have been giving thought to that vision. Among them are the Central Valley Joint Venture, the San Joaquin Valley Greenprint, the Central Valley Landscape Conservation Project, and the Endangered Species Recovery Program at CSU Stanislaus. Regionally, the Tulare Lake Watershed Partnership is doing impressive work, River Partners is working on floodplain restoration in the northern Valley and the Nature Conservancy is working on a number of projects including recovery of upland species.

FIGURE 2. San Joaquin Valley Pre-1900 Historic Vegetation Base Map (

While individual restoration projects can provide targeted benefits, ecologists also see the need for connectivity–core areas of different habitat types and establishment of corridors that connect them to preserve species and their genetic diversity. Dr Patrick Huber, at UC Davis, started his work on this over a decade ago (Figure 1). If the ultimate plan calls for core areas and connecting corridors, what should these areas be restored to? Frequently the easiest path to restoration is reversion to an historical state: the system of grasslands, woodlands, wetlands and other ecosystems that existed historically on the Valley Floor (Figure 2). Agreement is needed on how these fundamental concepts can be used to prevent what otherwise might be haphazard land retirement and instead develop a plan with real environmental benefits.

The Valley is likely going through its biggest change in 60 years. Land repurposing is inevitable, but by drawing on a wealth of ecological expertise and demanding sensible use of resources, the vision of a Valley that is biologically diverse, while still maintaining a strong economy and communities is worth working for.

The author can be reached at

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