Resuspending Organisms from a Rangeland Stream Bottom

Abstract

ABSTRACT BACTERIA from livestock wastes enter streams with run-off and are deposited directly when animals have access to the stream. While the exact fate of all of the organisms is not known, some of the bacteria settle out into the sediment on the stream bottom. This study examined resuspending organisms from the stream bottom. Bear Creek flows through a semi-arid rangeland in Central Oregon. The stream bottom was disrupted (raked) at three locations along Bear Creek. The stream was monitored to determine the change in the concentration of fecal coliform (FC) and fecal streptococcus (FS). Cattle locations were also recorded throughout the study period. The rakings resuspended 1.8 million to 760 million FC per m^ and from 0.8 million to 5,610 million FS per m^. Cattle access to the stream increased organism concentration in the underlying sediments.