In order to reduce the likelihood of heavy metal discharges into the bay, this facility shutoff their graving docks dewatering system. As a result, both the walls and the slab had to be re-evaluated for external water pressure due to groundwater, thereby establishing the maximum allowable internal and external water levels. Since the relative water level between the inside and outside of the dock was such a critical factor, it was necessary to account for the discharge capacity of the sump pump system and the time-dependent inflow through the dock’s flood gates.
Our engineering team developed a discharge and flooding procedure that maintained relative water levels between the inside and the outside of the graving dock so as not to damage the graving dock slab or walls. Our procedure was implemented during a ship launch and proceeded without incident.