| Popis: |
In this study, the AGNPS (Agriculture Non-point Source Pollution) model in conjunction with an ArcView GIS interface called AVNPSM was used to determine locations of vegetative buffer strip effectiveness on reducing sediment load within a 1,726-acre (690 ha) agricultural watershed located in mid Michigan. Modeling scenarios consisted of simulating the hydrology and sediment transport throughout the East Bad Creek watershed for a baseline scenario (no buffer) and a buffer strip scenario (incorporating a 30-meter vegetative buffer strip around all stream segments). The results showed a 17% decrease in sediment load at the watershed’s outlet for a 10yr-24hr storm. Using the simulation results, the placement of buffer strips within the watershed was prioritized on three different scales, on a stream segment level, a field boundary level, and on a cell-by-cell basis. The stream segment buffers and field buffers were ranked based on their overall ability to reduce sediment load into the stream. The reduction in sediment yield from the stream segments and the fields varied from 3.49 to 58.54 tons and 0 to 19.31 tons, respectively. The individual cells were deemed efficient if they filtered greater than 0.5 tons. The cell-by-cell evaluations highlighted specific critical areas of buffer efficiency, where the stream segment and field evaluations identified specific stream segments and fields to target for buffer placement. The AGNPS model along with the AVNPSM GIS interface demonstrates that agricultural watersheds can be quickly and efficiently evaluated to target locations of buffer placement. Therefore, helping watershed managers implement vegetative buffer strips in site-specific areas within the watershed to employ efficient implementation of conservation management programs. |
