Redwood City would like to thank Redwood Shores residents for their patience during the unfortunate discharge of raw sewage into the lagoon on August 25th and the resulting temporary advisory against recreational use of the water.
As most readers will recall, at around 3 pm on that day a pressurized sewer pipeline ruptured near Davit Lane and Anchor Circle. Raw sewage was discharged onto the surface, entering six nearby garages and flowing into the adjacent lagoon.
City crews were on the scene shortly after the pipeline failure and began work to identify and repair the break. Contractors and specialized cleanup crews were also on site, and all appropriate regulatory agencies were notified. Through the City’s automated CodeRED emergency phone notification system and warning signs posted at beaches, along with extensive media coverage, residents were advised to avoid any contact with the lagoon water. Through a series of valves, gates, and pumps the City prevented the exchange of water between the lagoon and the bay.
After first expecting that the failure was from a broken valve, it turned out that instead the break was actually in a section of pipeline, which required a more extensive and lengthy repair process. During the time it took to repair the break, the sewage flow was continually being pumped into tanker trucks and transported to the nearby sewage treatment plant pump station.
Initially, the City reported a spill of 5,000 gallons which was an estimate put forth within the Two-Hour Notification time period required by the San Francisco Bay Regional Water Quality Control Board. That initial estimate was, by necessity, made while the spill was still in progress. Once the spill was stopped and upon further analysis of all the data, the City reported a revised calculated estimate of 48,000 gallons.
Subsequent testing of the lagoon water showed high levels of coliform bacteria including E.coli, and so the City continued its advisory to avoid any contact with the lagoon water. Several more CodeRED phone calls were made to residents to keep them apprised of the situation.
On September 1, the lagoon water was treated with a bactericide, with concurrence by the Regional Water Quality Control Board. Further testing was showing some improvement in the water quality, likely in combination with sunlight breaking down the material, and natural bacterial die-off.
However on September 2, just before the Labor Day weekend, the tragic crash of a small plane into the diamond basin area of the lagoon further complicated the City’s ability to re-open the lagoon to public use, since there was concern with the potential for fuel and oil in the water. Further, the Federal Aviation Administration and other authorities became involved, thereby precluding the City from making an independent decision at that time on reopening the lagoon.
On September 7 the San Mateo County Environmental Health Department informed Redwood City that the water quality in the Redwood Shores lagoons was safe for normal human contact. The next day, the City removed its advisory concerning contact with the water, and informed residents that they could resume normal recreational activities in the Redwood Shores lagoon.
The City’s investigation into the cause of the pipeline break is still underway, and no conclusions have yet been reached. It’s important to let residents know that the City does have an extensive preventative maintenance schedule for the entire sewer system involving regular, frequent inspection of pump station systems, in addition to 24/7 automated remote monitoring.
This unfortunate set of circumstances is a reminder of how important it is for residents to register their phone numbers to be notified of emergencies in their neighborhood. Please be sure to go to www.redwoodcity.org/codered to sign up, or update your contact information.