This project required a 40 foot deep excavation for multi-use office building with an underground parking garage. Dewatering was needed to keep the excavation dry during construction. This was done using a dewatering well system and shoring. Groundwater was contaminated with Volatile Organic Compounds (VOCs). 41,000 cubic yards of soil was removed and approximately 130 million gallons of water required treatment over the course of the project.
The water treatment was originally designed for a 200 gpm system to treat for pH, turbidity, and hydrocarbons under a California Regional Water Board Fuels permit. The system was upsized to 700 gpm to handle the actual groundwater in-flows using open top weir tanks, a sand filter system, and a hydrocarbon removal system. This system was fully automated and maintained compliance with the permit for the duration of the project.