Mission Basilica San Diego de Alcalá
Some Uses of Locally-quarried Stone

The San Diego Mission Stone Flume/Aqueduct & Dam

The original location at which Father Junipero Serra founded the San Diego Mission in 1769 was at what is known today as “Presidio Park,” which is located above Old Town.  Due to the lack of a dependable source of water, the mission was moved to its present location in Mission Valley five years later.  The friars located a good location for their stone dam and basin about six miles up the San Diego River.  Construction started in 1809, and the San Diego Mission’ Indians provided the labor to build the stone dam and flume/aqueduct.  According to archeologist Ruth Alter’s online article, “The Spanish Period 1769-1822”:   (This article details the materials used in the construction of the aqueduct and dam.)

“While all of the California missions had some sort of water delivery system, the dam and flume constructed for the Mission San Diego de Alcala was by far the most ambitious.  Built across the head of Mission Gorge, the 244-foot long, 13-foot thick, 13-foot wide dam was constructed of stone and cement on exposed bedrock, creating a permanent reservoir behind it.  Water was released through gates and spillways into a 6-mile long gravity fed tile lined flume, down the gorge and Mission Valley, ending in a settling basin near the Mission. Construction was completed by 1815....”

The secularization of the San Diego Mission started in 1833 and ended by 1867, at which time the dam was no longer used by the mission and fell into disrepair and mostly ruins.  Ruth Alter’s article states that “The remains of the dam are still in place, but the flume system is long gone.”  You can still visit the Old Mission Dam, which today is a part of the Mission Trails Regional Park.  The Old Mission Dam is a nationally registered historic landmark.

More information and photographs about the San Diego Mission aquduct and dam are available on the following web sites: (1) Old Mission Dam: North east end of Father Junipero Serra Trail, National Trails Regional Park web site; (2) Hidden San Diego: Old Mission Dam: Mission San Diego’s water source is tucked away upriver, By Inigo Figuracion, About.com Guide; (3) “Old Mission Dam,” on Wikipedia; (4) “Timeline of Water History in Hillcrest and San Diego, California” – a photograph of the old the old San Diego Mission Dam is also available on this web site.

The following postcard photograph was contributed by Jeff McGreevy. (Jeff is a member of the Santee Historical Society and the San Diego Gem and Mineral Society.) Jeff led us on a tour of some of the granite quarries in central San Diego County in May 2012. Peggy and Pat Perazzo.