…Excuse Me…My Force Main Has Gas

Pump Station 65 (PS65) is currently equipped to handle the projected 2015 peak wet-weather flow (PWWF) of 18.8 million gallons a day (MGD). However during a storm in 2004, the station's two 400HP pumps operated for a 12-hour period with a recorded peak flow of 20.2 MGD. Further, recent Public Utilities Department (PUD) projections indicate that 2015 dry-weather flows will be approximately 22 MGD. Pump station capacity upgrades are required to avoid serious and costly sewage spill to the adjacent environmentally sensitive Peñasquitos Lagoon. Understanding the hydraulic capacity and physical and operating condition of the PS65 force main (FM) were critical considerations for proceeding with the needed pump station improvements. The work efforts associated with the FM assessment – the pressure gauging; hydraulic analysis; external and internal inspection; and structural condition assessment - are reviewed and the resultant City findings and actions to date are described.