Four major California areas expected to deplete aggregate supply in next 10 years

June 18, 2013

Four major regions in California–San Diego, Sacramento, Fresno and the San Fernando Valley–are likely to deplete their permitted aggregate supply within the next decade, according to recent data from the California Geological Survey (CGS).

CGS released in March its 2012 update to its “Aggregate Sustainability in California” project, which, according to the California’s Department of Conservation, “provides general information about the current availability of California’s permitted aggregate resources.”

The project, which consists primarily of a report and a map, is mandated by the Surface Mining and Reclamation Act of 1975 (SMARA) and managed by CGS.

The map and report look at projected aggregate demand for the next 50 years and compares it with currently permitted aggregate resources in 31 regions of the state.

The report’s 50-year aggregate demand forecast states that South San Francisco Bay, Temescal Valley-Orange County and Western San Diego County are each “expected to require more than a billion tons of aggregate by the end of 2060.”

Following close behind are San Gabriel Valley and San Bernardino, which are each “projected to need more than 800 million tons of aggregate in the next 50 years.”

Smaller demand is anticipated from El Dorado County, Glenn County, Nevada County, Shasta County, Southern Tulare County, Tehama County and Western Merced County, which are each projected to need 100 million tons of aggregate or less over the next 50 years.

The report shows that approximately 4 billion tons of permitted aggregate reserves are in the 31 areas that the project studied.

However, based on the project’s fifty-year aggregate demand compared to the currently permitted aggregate reserves, four regions (San Diego, Sacramento, Fresno and the San Fernando Valley) have a maximum of 10 projected years of permitted aggregate reserves remaining.

Additionally, 13 areas have a projected 11 to 20 years of those reserves remaining, seven areas have a projected 21 to 30 years remaining and three have 31 to 40 years remaining.

Only two regions (Nevada County and Yuba City-Marysville P-C Region) have a projected 41 to 50 years of of permitted aggregate reserves remaining.

The project reports an estimated 74 billion tons of non-permitted construction aggregate resources could be located in the 31 regions. According to the report, “it is unlikely that all of these resources will ever be mined because of social, environmental, or economic factors.”

For more information about the “Aggregate Sustainability in California” project, visit

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