The Failure of the Baldwin Hills Reservoir Dam - Induced Seismicity Potential in Energy Technologies - page 195

The Failure of the
Baldwin Hills Reservoir Dam
On December 14, 1963, the dam built to contain the Baldwin Hill Reservoir located
in southwest Los Angeles failed, releasing 250 million gallons of water into the housing
subdivisions below the dam. Approximately 277 homes were damaged or destroyed and
five people were killed by the disaster (Hamilton and Meehan, 1971). Although there is
speculation that waterflooding operations in the Inglewood Oil Field (located to the west
and south of the reservoir) were partially to blame for the failure of the reservoir dam, the
dam itself did not fail due to an induced earthquake. Records from the Seismographic
Laboratory of the California Institute of Technology located 15 miles northeast of the
reservoir showed no earthquakes large enough to cause internal damage to the reservoir
during the period 1950-1963 ( Jansen, 1988). Instead, the sealing layers in the floor of the
reservoir failed due to the “creep” of several geologic fractures below the reservoir, which
caused the release of water through the floor of the reservoir that resulted in the structural
failure of the dam itself.
The Baldwin Hills Reservoir was constructed between 1947 and 1951 by the Los
Angeles Department of Water and Power. The reservoir was constructed on a hilltop and
was formed by a dam on the north side and earthen dikes on the other three sides, which
were constructed of materials excavated from the reservoir bowl. The soil under the res-
ervoir was composed of porous material and was bisected by three known geologic faults
( Jansen, 1988). The floor of the reservoir was made watertight by the use of two layers of
asphalt with compacted earth between them. Below the upper layer of asphalt and earth,
a level of pea gravel with tile drains was installed to allow the monitoring of leakage from
the bottom of the reservoir. Extensive discharge from the drainage system was recorded
during the initial filling of the reservoir, and filling was discontinued until repairs to the
reservoir could be made ( Jansen, 1988). Cracking in concrete portions of the reservoir was
noted as early as 1951.
The Inglewood Oil Field was discovered in 1924 and covered approximately 1,200 acres
when fully developed. At the time of the failure of Baldwin Hills Dam in 1963, the field had
more than 600 producing wells, and the closest wells were located within 700 feet of the
reservoir structure. The oil reservoir is divided into multiple compartments due to a series
of geologic faults. Several of these faults not only divide the Inglewood Oil Field but also
continue to the surface and are present on the site of the Baldwin Hills Reservoir. The depth
of the wells in the Inglewood Field is between 2,000 and 4,000 feet. Due to subsurface fluid
withdrawal, the ground level above the field exhibited a surface subsidence of approximately