9:09 AM: The King County Wastewater Treatment Division says Monday night’s thunderstorms led to a “power interruption” that resulted in a “brief overflow” from Barton Pump Station on the north side of the Fauntleroy ferry dock. They aren’t saying yet how long it lasted or how much wastewater overflowed, but they’ve closed the beaches at Lincoln and Cove Parks “until water quality testing confirms the water is safe.”
2:07 PM: KCWTD has answered our followup questions. First – the overflow volume is estimated at more than 101,000 gallons. KCWTD spokesperson Doug Williams says it was actually two overflows:
The station experienced a power bump (poor power quality that was not consistent) at 7:12 p.m. that triggered a fault in the pump. The standby operator was dispatched to the pump station to reset the pumps. There were two short overflow events, one for 12 minutes and the other for 11 minutes.
We also asked how and when the KCWTD crew was notified and when they arrived:
The pump sent an alarm, which was received by Main Control at West Point Treatment Plant, and a standby operator was immediately dispatched. The operator arrived at the pump station at 7:47 p.m. The pumps were reset by 7:48 p.m. The operator left, having fixed the problem, but returned at 8:30 p.m. after another power bump caused an alarm at 8:08 p.m.
This pump station was “upgraded” in 2015, so we asked why there wasn’t some sort of failsafe or backup to prevent this:
We are still evaluating the incident and pump performance. We suspect that inconsistent power quality shut the pump down, as it is designed to protect the equipment from fluctuating power (much like a surge protector, or tripped breaker in your home). Power monitoring equipment at the station showed that there was no loss of power, so the incident was initiated by poor power quality received at the station. Since there was no loss of power, the onsite generator was not engaged. The power seemed to surge and flicker, causing two different short overflows of 12 and 11 minutes (from 7:36 – 7:48 p.m., and again at 8:19 – 8:30 p.m.).