ABSTRACT
Attitudes towards environmental problems changed substantially in the years following 1969, both nationally and locally. The National Environmental Policy Act (passed in 1969) initiated a period in which proposed federal, and later state and local developments had to be assessed in terms of their predicted impact on the environment. Locally, too, many minds were directed towards the dangers to the community of earthquakes, following the serious earthquake in San Fernando Valley on 9 February 1971 (Los Angeles County Earthquake Commission 1971). Such changes were of little direct consequence to the slope and sediment problems of Los Angeles County. Between 1969 and the storms of 1978, there was modest population growth from 7.0 million to 7.4 million (including a huge influx from Mexico), urban growth, and re-development. The trends continued towards the completion of flood- and debris-control plans and the refinement of slope engineering practices, but funds for such activities were limited. Thus the impact of the 1978 storms on the county was in many ways similar to that of the previous major storm episode in 1969, but somewhat less severe: there was relatively little flooding associated with the major controlled river systems, but debris clearance constituted a major expense; and slope failures were widespread.
