The Failure of the Baldwin Hills Reservoir Dam - Induced Seismicity Potential in Energy Technologies - page 196

10 feet by 1964. In order to increase production, waterflooding operations were commenced
in 1954 and expanded in 1955 and 1961. These injection operations increased pore pressure
in portions of the oil field from 50 psi to over 850 psi by 1963 (Hamilton and Meehan,
1971). Injection depths were as shallow as 1,200 feet.
The dam structure failed due to subsurface leakage of reservoir water beneath the floor
of the impoundment and under the foundation of the dam itself. The subsurface leakage
was caused by a cracked seal extending across the floor of the reservoir in line with the
breach in the dam ( Jansen, 1988). Movement of the geologic faults crossing the floor of
the reservoir with downward displacement of 2 to 7 inches on the western side of several
faults caused cracking in the asphalt membrane seal and allowed water to enter the porous
soil beneath the dam. Later excavations of the bottom of the reservoir indicated that leakage
had occurred for an appreciable amount of time before the dam failure. The slow movement
of the faults beneath the reservoir has been attributed to (1) natural causes inherent in the
geologic setting, (2) subsidence of the ground surface caused by oil and gas operations or
by the filling of the reservoir with water, or (3) pressure injection of water in the Inglewood
Field at shallow depths for oil and gas operations and in the presence of a fault system.
REFERENCE
Hamilton, D.H., and R.L. Meehan. 1971. Ground rupture in the Baldwin Hills. Science 172(3981):326-406.
Jansen, R.B. 1988. Advanced Dam Engineering for Design, Construction, and Rehabilitation . New York: Springer.