Region San Joaquin Valley


The San Joaquin Valley comprises the southern portion of California’s Central Valley, and includes San Joaquin, Stanislaus, Merced, Kings, and the western parts of Madera, Fresno, Tulare and Kern counties. These counties are home to ~4 million people with Merced County ranking as the fastest growing county in the state. The region’s primary economic driver and land use is agriculture, making it the most productive agricultural region in the United States. The Valley’s climate is characterized by hot, dry summers and foggy, rainy winters.


The San Joaquin Valley region has already experienced increased temperature over the last 70 years and will continue to face rising temperatures. The annual average maximum temperature is projected to increase 4 °F to 5 °F by mid-century, and 5 °F to 8 °F by 2100. As ecosystem conditions change with the rising temperatures, the agricultural industry will face new pests, changing cropping patterns, and increasing frequency and intensity of extreme heat events.


Additionally, snowpack decline in the Sierra Nevada is increasing water scarcity in the San Joaquin Valley, which exacerbates ongoing dry wells, groundwater overdraft, and subsidence challenges. These will have dramatic impacts on the agricultural sector, as well as drinking water supplies, especially in the face of future drought. Faster snowmelt will threaten dam stability in the region, increasing the risk of catastrophic flooding. This region will also experience longer dry seasons, as precipitation patterns change.


Like other regions, the San Joaquin Valley will likely experience more frequent wildfire, which will further threaten drinking water supplies and increase soil erosion.


Although not a coastal region, sea-level rise is also a concern, as sea-level rise in coastal regions will travel through the Delta and threaten Delta communities, including San Joaquin County, through increased flooding.

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