Effects of Multiple Use on Water Quality of High-Mountain Watersheds: Bacteriological Investigations of Mountain Streams

David G. Stuart, Gary K. Bissonnette, Thomas D. Goodrich, William G. Walter
1971 Applied microbiology  
Bacteriological studies in 1968 and 1969 corroborated earlier findings that a municipal watershed which had been closed to public entry since 1917 yielded water with four to six times the coliform count found in an adjacent mountain watershed open to recreational activities. Similarly, chemical investigations showed higher concentrations of most ions in water from the closed area. Physiological differentiation of coliform and enterococcal bacteria revealed similar types of organisms in both
more » ... al droppings and stream water, with fecal coliforms accounting for as much as 70% of the coliform counts observed in the closed area in 1969. Opening of the closed drainage for limited recreation and expanded logging operations in the spring of 1970 coincided with an unexpected decrease in bacterial contamination of that stream. It is postulated that these human activities drove from the watershed a large wild animal population which had contributed substantially to the previous bacterial pollution. It would seem that the practice of closing high-mountain watersheds to public entry is questionable if governmental standards for water quality are to be met, and it also seems that the standards themselves should be reexamined. Water quality in high-elevation mountain watersheds is affected by recreation, grazing, and timber management. As these watersheds are developed for a variety of uses, the quality of the streams must receive prime consideration. However, as Teller (Ph.D. Thesis, Univ. of Washington, Seattle, 1963) indicates, there is insufficient information to determine what natural water quality is or to what extent bacterial numbers in a stream can be attributed to manmade or to natural causes. The fact that Fair and Morrison found bacterial pathogens in "clean" streams high in the Colorado Rockies substantiates this (7). The effect of clear-cut logging on the water temperature of mountain streams with small flow volumes may be extremely significant in the management of Pacific Northwest watersheds according to Brown and Krygier (5). The question of public use of reservoirs and municipal watersheds has been studied by Carswell et al. (6) and Van Nierop (Ph.D. Thesis, Cornell Univ., Ithaca, N.Y., 1963), resulting in essential agreement that recreation in and around water supplies results in little or no deterioration
doi:10.1128/am.22.6.1048-1054.1971 fatcat:ejle6ogup5a73kd2zg7qh57yu4