St. Francis Dam Disaster Has a Message for Today

We who live in the Santa Clara River Valley must be aware that the ghosts of the 1928 St. Francis Dam disaster, recounted in the article “Exhibit Gives Snapshot of a Disaster, History” (April 17), have an important message to send us.

Both the operators and owners of dams and those exposed to potential flooding downstream should be aware of the hazards of dam failure or mis-operation. There are people living in homes downstream.

To focus national attention on the importance of dam safety, the Federal Emergency Management Agency (FEMA) is sponsoring the first National Dam Safety Awareness Day on May 31. An important theme is to raise the awareness of communities affected by dams and to take actions to make their communities aware of potential hazard.

This is a good time to examine the dams in the Santa Clara River basin.

The Times article cited states: “No one is certain what caused the [St. Francis Dam] collapse. Possibilities range from unstable ground . . . to the concrete used . . . and an underlying fault.”

To me it is obvious what caused the collapse. It was imprudent decisions made by persons in authority. The response of the works of man to the forces of nature are the principal culprits causing harm to life and damage to property in California, the disaster theme park of America.

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Today we have a total of 648,000 acre-feet of water--17 times the storage capacity of the St. Francis Dam--sitting in the reservoirs of four large earthen dams in the seismically sensitive upper watershed of the Santa Clara River: Piru Dam, Castaic Dam, Pyramid Dam and Bouquet Canyon Dam.

The U.S. Army Corps of Engineers’ National Inventory of Dams gives each of these four dams a rating of “H” (High), indicating the potential hazard to the downstream area resulting from failure or mis-operation of the dam or facilities.

A 1984 multiple-failure scenario showed that about 65% of the inhabitants of the valley would be made homeless in the event of a multiple failure and mis-operation. Fatality figures were not estimated.

The U.S. Bureau of Reclamation, after a review of the design of the Casitas Dam built in 1959 in the Ventura River watershed, is now doing a $40-million seismic upgrading of the dam. The design criteria is an earthquake of magnitude 7, 3 kilometers from the dam.

It does not require a dam failure to cause a dangerous flood flow. The mandatory discharge of inflow overfilling the reservoir or flowing over uncontrolled spillway crests can add to the runoff in the river. This occurred in February 1998 in the Santa Clara River with releases from Piru and Bouquet Canyon.

Similar releases from Central Valley dams in 1997 caused floods and levee failures. Two months ago, disastrous floods in the African nation of Mozambique were similarly augmented by mandatory releases from an upstream dam.

In the case of the St. Francis Dam, William Mulholland, chief engineer of the Los Angeles Department of Water and Power, surrounded by a flawed organization with a siege mentality, used poor engineering judgment, improper geological consultation, faulty engineering design and development of the dam site to the maximum storage capacity possible without proper consideration of the consequences.

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There are Mulholland-type personalities leading flawed organizations in decision-making positions in various state, county and local agencies. This can be attested to by the ongoing development pressures to build housing units in the Santa Clara River flood plain in both Los Angeles and Ventura counties.

Developers are attracted to the mild slopes of alluvium deposited in the Santa Clara River flood plain. This development should be held up until the safety of the four major dams and reservoirs in the Santa Clara River are carefully evaluated, perhaps by an independent agency such as the U.S. Bureau of Reclamation.