The effects of cattle grazing on stream stability have been well documented for the western portion of the U.S., but are lacking for the east. Stream and riparian damage resulting from grazing can include alterations in watershed hydrology, changes to stream morphology, soil compaction and erosion, destruction of vegetation, and water quality impairments. However, few studies have examined the successes of best management practices (BMPs) for mitigating these effects. The objective of this project was to assess the ability of two common BMPs to reduce streambank erosion along a central Kentucky stream. The project site consisted of two replications of three treatments: (1) an alternate water source and a fenced riparian area to exclude cattle from the stream except at a 3.7 m wide stream ford, (2) an alternate water source with free stream access, and (3) free stream access without an alternate water source (i.e., control). Fifty permanent cross−sections were established throughout the project site. Each cross−section was surveyed monthly from April 2002 until November 2003 Results from the project indicated that the incorporation of an alternate water source and/or fenced riparian area did not significantly alter stream cross−sectional area over the treatment reaches. Rather than exhibiting a global effect, cattle activity resulted in streambank erosion in localized areas. As for the riparian exclosures, changes in cross−sectional area varied by location, indicating that localized site differences influenced the processes of aggradation and/or erosion. Hence, riparian recovery within the exclosures from pretreatment grazing practices may require decades, or even intervention (i.e., stream restoration), before a substantial reduction in streambank erosion is noted.

Gas-Phase Biofiltration technology is widely utilized for treating ammonia gas (NH 3 ) with one of its potential detrimental by-products being nitrous oxide (N 2 O), a potent greenhouse gas (100-y radiative forcing 298 times greater than carbon dioxide). The present work was conducted to investigate the relation between NH 3 removal during biofiltration and N 2 O generation as a product of incomplete denitrification during the start-up of gas-phase compost biofilters. Four laboratory scale tubular biofilters in up flow mode (20 s residence-time) were studied for 21 days: 3 replicates were subjected to 16 ppm v (0.78 g m À2 h À1 ) of NH 3 and a statistical control not subjected to NH 3 . Ammonia concentration differences between biofilter inlet (Bottom ¼ 16 ppm v ) and outlet (Top) and N 2 O concentration differences between biofilter outlet (Top) and biofilter inlet (background concentrations at the bottom) were used to determine the extent of the correlation between NH 3 removal and N 2 O generation. Correlations with CH 4 and CO 2 were also reported. The high Spearman correlation coefficients for the three replicates (r ¼ À0.845, À0.820, and À0.841, with P 0.0001 for replications A, B and C, respectively) suggested that availability of nitrate/nitrite owing to NH 3 nitrification favored conditions for N 2 O generation as a subproduct of denitrification. The statistical control received no NH 3 inputs and did not generate N 2 O. Therefore, the results indicated that the process of NH 3 removal was a trigger for N 2 O production. Carbon dioxide and N 2 O were moderately correlated. Methane and N 2 O were weakly correlated and only for replicate C. No significant correlation was found for the Statistical Control between N 2 O and CH 4 .