“…This confounds E. coli fate and transport modeling (Harmel et al, 2006a, 2010). Large measured E. coli concentration variations in edge‐of‐field and small watershed runoff (Donnison et al, 2004; Goto and Yan, 2011; Harmel et al, 2013, 2016; Wagner et al, 2012; Wittman et al, 2013) and soil as a potential E. coli source in upland watersheds are two of these factors. Soil E. coli concentrations up to 20,800 colony forming units (cfu) g −1 have been measured in tropical and temperate soils (Byappanahalli et al, 2006, 2012a, 2012b; Goto and Yan, 2011; Ishii et al, 2006; Pandey and Soupir, 2013; Soupir and Mostaghimi, 2011), and streambank soil may be a significant source contributing to streams (Byappanahalli et al, 2003; Desmarais et al, 2002; Solo‐Gabriele et al, 2000).…”