Abstract:
A documented case history of riparian grazing at Oregon State University's
Soap Creek Ranch was conducted from 1999 to 2001. Impacts of four different
riparian grazing treatments were evaluated. Emphasis was placed on investigating
the relationship between riparian cattle use and water quality.
Through a series of carefully designed and replicated measurements, each
grazing treatment was evaluated on how it affected (1) riparian forage grass
utilization; (2) woody shrub cover and density; (3) streambank vegetative cover at
key water access points; and (4) total coliforms and E. coli concentrations as an
indicator of water quality.
Average stubble height measurements on Festuca arundinacea, did not
adequately represent riparian livestock impacts. Shrub density and percent cover
did not change significantly when cows had access to the riparian zone. No
differences were measured between water gaps open to cattle vs. those closed to
cattle until the end of the second year of riparian grazing. Total coliforms and
E. coli bacteria concentrations changed dramatically throughout the two-year study.
Efforts should be made however to limit cattle access to Soap Creek in the fall. During this time, cattle linger in and around the creek and occasionally defecate
directly into the water.
