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Regional Monitoring Program (RMP) Small Tributaries Loading Strategy: Modeling and Trends Strategy 2018

Jing Wu, Philip Trowbridge, Don Yee, Lester McKee, Alicia N. Gilbreath | September 3rd, 2018


The Small Tributaries Loading Strategy (STLS) (SFEI, 2009) is a collaboration between the RMP, the Water Board, and Bay Area stormwater programs to address information needs associated with improving understanding about the sources, pathways, loads, trends, and management opportunities in relation to watershed-derived pollutants of concern (POCs). Elements contained in this Strategy may be conducted via RMP collaborative efforts, or independently by the Water Board or Bay Area stormwater programs outside of, but in coordination with the RMP. The current priority POCs are mercury (Hg) and polychlorinated biphenyls (PCBs), for which there are identified impairments and cleanup plans in place. The San Francisco Bay Hg and PCBs total maximum daily loads (TMDLs) reports (SFRWQCB, 2006; SFRWQCB, 2007) call for a reduction in tributary loads by 50% and 90%, respectively. In response, from 2010-2015, during the first term of the Municipal Regional Stormwater Permit (MRP 1.0) (SFRWQCB, 2009; 2011), a number of pilot efforts were initiated, focusing mainly on PCBs, to better understand the potential cost-effectiveness for a range of management options and the level of opportunity (the number of polluted sites or the amount of mass associated with polluted sites, property ownership and other factors). During the second term of the MRP (MRP 2.0) (SFRWQCB, 2015), efforts have been made to move from pilot testing to a greater amount of focused implementation. All of these past, current, and future efforts also aim to address (but at a lesser level) multiple benefits for other POCs including current-use pesticides and emerging contaminants, for which there is interest in monitoring the potential for biological impact. These are lower priority at the present, but in the longer term, the STLS Trends Strategy could address these and other POCs in a more focused manner.

Keywords

modeling, planning and management, pollutants, stormwater, water quality