Abstract
Debris flows generated by soil slumps which occur during heavy rainstorms present a greater risk of death and injury to residents of Southern California than do all other types of slope failures combined. Since World War II, development in the hillside areas has greatly accelerated, resulting in the construction of many residences in the paths of potential debris flows.
A method of predicting the potential for soil slumps occurring at individual sites has been devised based on field observations of over one hundred such failures. Numeric values of 0 to 4 are assigned to three factors for each site: the soil type, the slope gradient, and the influence of concentrated drainage. The sum of these values yields a practical guideline for evaluation of the potential for soil slumps occurring at individual sites.
Information on the potential for soil slumps occurring can be utilized in the creation of a warning system to advise residents of potential hazard and to guide recommendations for the placement of protective devices. Poured retaining walls, deflection walls, stem walls, debris basins, and debris fences are the protection devices recommended for the protection of structures from damaging debris flows.
