Some Drought Impacts to Central Valley Soils and Society in California.

The impacts from drought in the Central Valley of California are rapidly changing soils and landscapes. Drought also takes a toll on people and society as they try to adapt to changes that drought has wrought. Gross value of agricultural production in 2012 was 32.4 billion dollars just in the San Joaquin Valley that covers the south half of the 725-kilometer long Central Valley. The San Joaquin Valley consistently ranks eighth of the top twelve counties in California for agricultural production according to the California County Agricultural Commissioner’s Reports, 2012. Response to drought is currently affecting agricultural production and is also significantly affecting the choice of future agricultural crops. Most of the impacts are relatively well known while some are subtle. The speed at which these impacts are occurring is unprecedented.

Groundwater makes up nearly 60 percent of California’s water use during dry years. This creates a number of problems that are obvious in some cases and subtle in others. Subsidence as a result of aquifer compaction due to ground water withdrawal is subtle, however measurements of changes in elevations make it clear that subsidence is accelerating and migrating into areas that were relatively unaffected by subsidence previously. Subsidence is occurring as farmers strive to continue farming by digging deeper wells which is very expensive. The cost of pumping irrigation water from these deeper depths has reduced profit margin. The quality of deeper ground water used for irrigation is generally much poorer than surface waters used over past decades.

Salinization of soils due to application of saltier irrigation water from deeper wells is rapidly beginning to affect some of the best soils in the Central Valley. Water from deeper wells that has replaced water from the California Aqueduct and related systems is at least three times saltier than irrigation water that has been used over the last few decades. This trend is resulting in degradation of the soil and will not easily be reversed.

Societal changes are rapidly occurring because of drought. Some of these changes include:

1. Removal of permanent crops following decades of unprecedented increase.
2. Lack of work for farm workers as profit margins are reduced due to ground water pumping costs and fewer crops planted.
3. Increase in valley fever, or coccidioidomycosis, caused by soil-borne fungi endemic to southwestern United States.