History: Building the Bay Area
As one of the oldest quarries in California, Pacifica’s limestone quarry supplied rock products for construction projects from 1776 until mining operations closed in 1987. Formerly known as the Rockaway Quarry, the site is currently owned privately.
The Gaspar de Portolá party discovered San Francisco Bay from Sweeney Ridge, east of Pacifica. As early as 1776, limestone was quarried from the site for building and whitewashing the San Francisco Presidio and mission buildings. The Spanish also used Mori Point limestone to create the whitewash for the San Pedro y San Pablo outpost in the San Pedro Valley.
Commercial mining began at the Rockaway Beach Quarry as a continuous enterprise in 1907. Excavated material provided ballast for the Ocean Shore Railroad and construction material to rebuild San Francisco after the 1906 earthquake.
Quarry business expanded during this period due to the increased pace of construction during World War II, with concrete aggregate, ballast, and high-grade limestone excavated from the site. Sand dredging business began, and roads and pits were added.
Commercial quarrying ended in 1987, leaving the land in a degraded condition with unstable slopes, bare rocky bluffs, and disturbed soil vulnerable to invasive vegetation.
A portion of the land was transferred to the City of Pacifica for the Calera Creek Water Recycling Plant and Calera Creek restoration. Construction started in 1996 and the new plant began treating wastewater in 2000. Recycled water from the facility currently sustains wetlands along the creek and supports habitat for a variety of wildlife species.
After closure of the quarry operations, the previous owners allowed the land to degrade. Invasive, non-native species have spread across the landscape. Soil erosion threatens the coastal bluffs and trails.
Information Sources: Historic Resource Study For Golden Gate National Recreation Area In San Mateo County, National Park Service and City of Pacifica Website