Did Streambank Fencing Affect Surface-Water Quality?
Low-flow data generally showed similar responses from the pre- to post-treatment period for untreated and treated sites for nutrients and suspended sediment (table 1); however, fencing effects were evident. About 96 percent of the total-N concentration for all low-flow samples was in the form of nitrate N. Low-flow periods contributed from 84 to 91 percent of the total-N yield at the continuous monitoring sites. From the pre- to post-treatment period, all sites showed decreased yields of N during low-flow periods because of lower stream discharge and lower concentrations. Yield reductions were greater at treated sites (25-26 percent) than at the control/upstream sites (11 percent) (table 1). On the basis of ANCOVA analysis, relative reductions from the pre- to post-treatment period in low-flow yields of total N and nitrate N were 17 percent for T-1; conversely, relative increases in low-flow yields of total N and nitrate N were 9 to 11 percent for T-2. P concentrations for low-flow sam