Coliforms as an indicator of water quality in wildland streams
Journal of Soil and Water Conservation , 40 , 1985

Bohn, C.C., Buckhouse, J.C.

With renewed interest in nonpoint pollution sources and the growing interest in riparian zone management, land management agencies have increased the number of monitoring and research programs on wildland streams. While the cause remains unknown, coliform populations exhibit daily and annual cycling. Regardless of the specific peak periods, the implication of these fluctuations to management and research programs is clear: individual samples represent the sanitary status of a stream only at the time of sampling. Coliforms enter streams with overland flow during the runoff season. They may also enter streams from groundwater flow following storms. The final and most obvious source of fecal coliforms in surface water is direct contamination from animals defecating into the water. Coliform counts are a valid indication of the sanitary status of a body of water only if pathogens respond to these situations in the same way as the coliform bacteria, which is a question to be answered. Coliforms are not satisfactory indicators for the protozoan Giardia spp., which is a growing concern in wildland waters. Fecal coliform and the salmonella species behave very much alike in natural waters. But both may die off while other pathogens remain viable.