Water quality improvements following riparian restoration in two vermont agricultural watersheds

Meals, D.W., Manley, T.O., Manley, P.L., Mihuc, T.B.

Achievement of management goals for Lake Champlain will require significant reductions of phosphorus (P) loads from agriculture, the dominant nonpoint source (nps) in the Basin. Cost-effective nonpoint source reduction strategies must be based on reliable treatment techniques beyond the basic erosion control and animal waste storage practices promoted in the past. The Lake Champlain Basin Agricultural Watersheds National Monitoring Program (NMP) Project evaluated the effectiveness of low-cost livestock exclusion, streambank protection, and riparian restoration practices in reducing concentrations and loads of nps pollutants from grazing land at the watershed level. Treatment and control watersheds in the Missisquoi River Basin in northwestern Vermont were monitored from 1994 through 2000 in a paired-watershed design. Monitoring included stream discharge recording, flow-proportional sampling for nutrients and suspended solids, intensive grab sampling for indicator bacteria, and tracking of land use and agricultural management in the watersheds. Treatment (riparian fencing, alternative water supplies, protected stream crossings, and streambank bioengineering) was completed in 1997 at a cost of similar to$40,000. Landowner participation in land treatment was entirely voluntary and all treatments were 100% cost-shared by the project and cooperators. Post-treatment data documented significant reductions in nutrient and suspended solids concentrations and loads (similar to20-50%) and bacteria counts (similar to40-60%) from both treated watersheds. Although water quality in one treated watershed was seriously compromised by mismanagement of one large farm in the final year, the project clearly demonstrated the potential for inexpensive riparian zone restoration to reduce nps pollution from grazing lands in Vermont.