Hydrologic conditions were evaluated on the basis of a continuous record of streamflow at each sampling site. Fecal coliform densities are typically much greater in streams during runoff conditions because of nonpoint-source contributions from the watershed. The median density is a measure of the central tendency of the data and is that value in an ordered set of data above and below which there is an equal number of values. Median fecal coliform bacteria densities in samples of base flow for both the 1997 and 1998 water years did not exceed water-quality criterion for noncontact recreation, which is the classified use of the streams at all sampling sites in the Cheney Reservoir watershed. The implication of large median densities in tributary streams might be to expect large densities within Cheney Reservoir.
Bacteria are subject to die off and predation by other organisms.
The physical processes of dilution by reservoir water and deposition also play a role in decreasing in-lake bacterial densities. Topeka, Kansas, Secretary of State, p. 190-193.