Watershed Evaluation of Beneficial Management Practices (WEBs Project) in Southern Alberta, Canada.

The Lower Little Bow watershed in Alberta is one of seven WEBS watersheds across Canada.  Five BMPs are being evaluated in this watershed.  They include streambank fencing, off-stream watering with no fencing, conversion to greencover, grass and mixed grass-shrub buffers, and manure management.  The major water quality parameters evaluated were sediment (TSS), nutrients (TN, TP) and bacteria (E. coli).  Preliminary results indicate that streambank fencing is generally effective at maintaining water quality for TSS, TN, TP, and E. coli.  Exclusion grazing did not improve runoff quality compared to grazed pastures, suggesting direct fecal contamination of the river was more likely than runoff from adjacent land.  In contrast, the effectiveness of off-stream watering with no fencing depended on the variable of interest.  Little or no runoff into grass buffers located on flat sandy soils adjacent to the river indicated that buffers in this watershed are not required.  Conversion from barley to alfalfa did not improve runoff quality, and was related to the greater surface residue or mulch present under barley.  Applying manure based on P instead of N reduced certain dissolved forms of P, but it did not reduce TP in runoff.   Preliminary results indicate that of the five BMPs investigated, streambank fencing seems to be the most effective BMP.