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San Diego's Construction Aggregate Shortage

Basically San Diego County’s aggregate shortage problem is very simple; demand is steadily increasing while aggregate production within the county is steadily declining. Currently the county has been importing 50% of our aggregate to satisfy demand. Supplies have been decreasing because the number of quarries in the county are declining.

Only 1 new quarry has been permitted in the county in the last 30 years.

Resources vs. Reserves

Before proceeding, we must define two terms: resources and reserves. Resources are the total amount of construction aggregate material that exists in the ground in a given region. Reserves are the total amount of construction aggregate material that has been permitted by government agencies for extraction.

San Diego County does not lack construction aggregate resources as evidenced by the 5.7 billion tons of aggregate identified by the Department of Conservation in Special Report 153. However, over the past 30 years, no new reserves have been permitted by San Diego's government agencies. This is due to strict environmental regulations, strong community opposition, and the high risk and capital expenditure involved in implementing a mining operation.

Why does San Diego County have so many resources yet so little reserves?

Existing urban development. Once an area of land has been developed, the resources underlying the development are essentially lost.

Habitat Conservation is the area of land that has been designated within one of the habitat or species conservation programs. Aggregate resources on land designated under one of these programs either can't be mined or the mitigation requirements make the project economically infeasible.

Military use of the land. All of these limiting factors obstruct the development of aggregate resources in one way or another.

The combined effect of these factors is the difficulty in permitting new aggregate production sites as evidenced by San Diego County has only permitted 1 new site in the past 30 years.

Land Use Constraints for Extraction

The areas that are known to have aggregate quality resources in the County are indicated in orange (MRZ-2). There are many other areas in the County that have aggregate quality resources but have not yet been identified by the California Geological Survey. Unfortunately 95% of the areas indicated in orange are not accessible for aggregate resource development due to competing land uses. Thus, more areas need to be identified within the County that can be conserved for aggregate resource development.