MWD Pipeline Rehabilitation
UltraSystems conducted an environmental review to identify significant hazardous material issues that could affect the construction, feasibility, and cost of proposed rehabilitation of an underground Prestressed Concrete Cylinder Pipeline (PCCP) along 29.7 miles of the Second Lower Feeder from the Metropolitan Water District (MWD) Robert Diemer Water Treatment Plant (Yorba Linda) in Orange County to the Palos Verdes Reservoir (Rolling Hills Estates) in Los Angeles County, California. UltraSystems researched and reviewed federal and California regulatory agency database information regarding (1) past owners, occupants and activities up to ¼ mile on each side of the alignment, (2) National Priority List (Superfund) sites within one mile of the alignment, and (3) aerial photographs to assess known or suspected past activities that could adversely affect proposed rehabilitation along the pipeline alignment. Following the review, UltraSystems completed site visits to specific areas of environmental concern to identify and resolve access issues for future environmental field sampling. UltraSystems prepared a detailed workplan and costs to install exploratory borings as near as feasible to proposed excavations to collect representative samples for potential contaminants that may be encountered. Two-inch diameter groundwater monitoring piezometers were recommended within or near four excavations east of the Los Angeles River and one excavation east of the Dominguez Channel to monitor temporal changes in groundwater levels and contaminant concentrations that may impact PCCP rehabilitation in areas of broad shallow contamination. The report and workplan were accepted by the MWD. The project was completed on time and within budget.