The San Francisco Public Utilities Commission (SFPUC) Wastewater Enterprise owns and operates a combined sewer system that collects and treats stormwater and wastewater generated by the City and County of San Francisco. The SFPUC is developing a Receiving Water Model (RWM) as part of its Sewer System Improvement Program (SSIP). The SSIP includes analyses of and planning for capital projects and operational improvements that, if implemented, have the potential to affect the frequency, location and duration of wet weather discharges from the combined sewer system. The RWM will enable the SFPUC to simulate the effects of changes in wet weather discharges on the quality of receiving waters so that this information can be used in the evaluation of potential SSIP projects and programs.

Alluvion has partnered with AECOM to conduct monitoring and sampling during wet weather discharge events at four site locations in San Francisco which includes; North Shore, Ocean Beach, Islais and Mission Creeks. Types of sampling include; combined sewer discharge (CSD) events which involves grab sampling through manholes without confined space entry, sampling of nearshore and offshore (vessel sampling) receiving waters during CSD events, depth profiles of receiving waters for conventional water quality parameters during CSD events, and current profiling using acoustic Doppler current profilers (ADCPs).