Bacteriological aspects of a mountain watershed

Numbers of fecal coliforms and fecal streptococci increased during the winter in a stream near a ski area. These numbers returned to background levels within a month after the ski area closed for the year. As the pollution events continued with time, the day of the week on which maximal numbers were obtained changed. Maximum numbers of these bacteria were seen in the afternoons when pollution was occurring. Minimum numbers were found in the morning. Fecal coliforms and fecal streptococci were enumerated in a stream above and below the ski area for three summers. Statistically significant differences in the numbers of these organisms occurred between the months studied, depending upon whether the statistics were run upon numbers per 100 mL or upon numbers passing a point per second.