• Studied internal effects (pressure surges) and external effects (tidal conditions) impacting outfall operation.
  • Air in outfall during startup resulted in air/water expelled from vents (line fill slam).
  • Solution involved strict control of the pump startup speed.

East Bay Outfall Venting Assessment

East Bay MUD
Oakland, CA

The East Bay MUD was experiencing venting problems in its Main Treatment Plant outfall. Flow Science and Carollo Engineers conducted a line fill slam test to determine the conditions under which the venting occurred. The field test and hydraulic modeling revealed a range of flows and tidal conditions where the outfall is flowing partially full. An increase in outfall flow which causes the pipeline to transition from a partially full condition to a full flow pipe condition was predicted to create a line fill slam in the outfall as the air was rapidly vented.