BEGIN:VCALENDAR BEGIN:VEVENT SUMMARY:Fecal pollution in urban streams: ecology, transport, and policy DESCRIPTION:Speaker: Stanley Grant, University of California, Irvine Talk Title: Fecal pollution in urban streams: ecology, transport, and policy Abstract: Fecal indicator bacteria (FIB) are the number one cause of river and stream impairment in the\n United States. In this talk I describe field and modeling studies aimed at identifying dry weather\n sources of FIB in the Santa Ana River, a wastewater effluent dominated stream in southern\n California. Multiple lines of evidence support the hypothesis that FIB in this stream originate\n primarily from in situ growth in streambed sediments. The measured flux of FIB from the\n streambed is >10 times the flux predicted from prevailing models of interfacial mass transfer\n across turbulent boundary layers, but similar to the flux of water between the stream and its\n hyporheic zone estimated from dye injection experiments. Thus, hyporheic exchange appears\n to control the trafficking of fecal bacteria, and perhaps other types of particulate organic\n matter, across the sediment‐water interface. From a policy perspective, in situ growth of FIB in\n riverbed sediments may lead to a decoupling of FIB and pathogen concentrations, and thus\n limit the utility of FIB as an indicator of recreational waterborne illness in southern California’s\n inland and coastal waters. These results also point to a possible environmental trade‐off\n associated with hyporheic zone restoration, in which increased nutrient processing by riverbed\n sediments is accompanied by increased flux of FIB to the overlying water column. Biography: Dr. Stanley Grant is a Professor in the Departments of Chemical Engineering and Materials\n Science (primary) and Civil and Environmental Engineering (courtesy) at the University of\n California, Irvine. Dr. Grant also has a summertime appointment as a Visiting Chair of Hydrology\n and Water Resources in the Department of Civil and Environmental Engineering at the\n University of Melbourne (Australia). Dr. Grant received a B.S. in Geology from Stanford\n University, and M.S. and Ph.D. in Environmental Engineering Science (minor in Applied Biology)\n from the California Institute of Technology. His professional interests include coastal water\n quality, environmental dispersion of pathogens, and fate and transport modeling. Professor\n Grant served on the US EPA’s Science Advisory Board (Drinking Water Panel, Science and\n Technological Achievement Awards Panel) from 2000 to 2009. Host: Sonny Astani Dept. of Civil and Environmental Engineering DTSTART:20110217T160000 LOCATION:KAP 209 URL;VALUE=URI: DTEND:20110217T170000 END:VEVENT END:VCALENDAR