Pictured above is the Pierce St Outfall, seen at two different stages of its life. The Pierce St Outfall (CSD10) was part of the North Shore Outfalls Consolidation (NSOC) until it was decomissioned in 2021. According to whispers CSD10 was decomissioned because surrounding citizens, particularly of the nearby yacht harbor, were discontent with a discharge structure so close. CSD10 had a unique discharge structure, with a diagonal weir splitting the length of the pipe before the outfall gate. The decomissioning included removal of 5-6 manhole covers, and the filling of the pipe with concrete (as pictured.) A parking lot drain previously connecting to the outfall was reconnected to the sewer with an 8" pipe placed inside before concrete was poured. It is also believed that because this pipe lacked a backflow prevention flap it flooded the Marina Green parking lot in October of 2021 when record rainfall filled the T/S structures consequentially backing up the pipe. Below are contract drawings from the decomissioning that illustrate the unique construction.
There is a well hidden history of sewerage in the Marina district, specifically on the waterfront. Digging into historical masterplans reveals the Marina Sewerage Plant, or pump station. Gigantic in size, it collected local wastewater and pumped it east of Fort Mason. This was likely abandoned during the construction of the T/S structures but its size and construction is of note. The most interesting features included a vent disguised as a flag pole, and sewerage pumped via iron pipe laid inside the Fort Mason Tunnel.
