Los Angeles Region Dredged Material Management - Design and Construction of the Aquatic Capping Pilot Project

The multi-agency Los Angeles Basin Contaminated Sediments Task Force (CSTF) was established in 1998 to develop a long-term management plan by 2003, for dredging and disposal of contaminated sediments from coastal waters in Los Angeles County. The plan's goal is to include measures to identify environmentally preferable, practicable disposal alternatives, promote multiuse disposal facilities and beneficial re-use, and support efforts for watershed management to control contaminated sediments at their source. To identify the most appropriate sediment disposal alternatives, four pilot and/or bench scale studies were conducted and led by one of the CDSF executive members, the Los Angeles District Army Corps of Engineers. This paper presents the design and construction of the Aquatic Capping Pilot Project. The project involved the dredging of 100,000 cubic meters of contaminated Los Angeles River Estuary (LARE) material and placing the material in the North Energy Island Borrow Pit (NEIBP) — a historic borrow pit used to construct Island White. After the material was placed, 68,000 cubic meters of clean material was dredged from the South Energy Island Borrow Pit (SEIBP) and placed as cap over the LARE material. The material used for the cap was previously dredged from Queens Gate channel and was disposed in the SEIBP.