Fig. 4. Escherichia coli concentrations in water and caged zebra mussels sampled daily in the Clinton River during the period of 1 to 8 Sept. 1997. Monitoring sites were at (A) downstream Clinton River (Site 13) and (B) north branch Clinton River (Site 12). Rainfall measured by the rain gauge located near Site 11 (see Fig. 1) is indicated by vertical black bars at the top