Environmental Assessment for Slope Stabilization Projects at Fort MacArthur, San Pedro, California.

摘要

An Environmental Assessment (EA) was prepared to analyze the potential for significant environmental impacts associated with upcoming slope stabilization projects at Fort MacArthur, San Pedro, California. An east-facing bedrock bluff approximately 5,000 feet (ft) long, ranging from approximately 10 to 40 ft high, is located along the eastern border of the Fort. Portions of the coastal bluff are known to have been marginally stable to unstable. Stability of the bluff is the subject of several geological and geotechnical investigations spanning the past three decades. Studies of the project area have documented historical landslides and slope failures dating back to the 1940s. The United States Air Force (USAF) divided the bluff into three defined areas for a phased slope stabilization effort: Phase I/II, Phase III, and Phase IV Slope. Phases I and II of the bluff are adjoining and were stabilized concurrently in 2006-2008. Phases I and II are collectively referred to as the Phase I/II area. The Phase I/II area is approximately 800 ft long and located near the midpoint of the bluff alignment (northern portion of the southern half of the bluff alignment). The Phase III area is approximately 1, 500 ft long and consists of the remaining portion of the southern half of the bluff alignment. The Phase IV Slope area consists of the remaining slope, approximately 2,700 ft.