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Title: SWAT modeling of Critical Source Area for Runoff and Phosphorus losses: Lake Champlain Basin, VT

item GHEBREMICHAEL, LULA - University Of Vermont
item WATZIN, MARY - University Of Vermont
item Veith, Tameria - Tamie

Submitted to: Soil and Water Assessment Tool International Conference
Publication Type: Proceedings
Publication Acceptance Date: 8/5/2009
Publication Date: 12/18/2009
Citation: Ghebremichael, L.T., Veith, T.L., Watzin, M.C. 2009. SWAT modeling of critical source areas of runoff and phosphorus losses: Lake Champlain Basin, VT. In: Proceedings of the Soil and Water Assessment Tool International Conference, August 5-7, 2009, Boulder Colorado. p. 385-393.

Interpretive Summary: An interpretive summary is not required.

Technical Abstract: Lake Champlain, located between Vermont, New York, and Quebec, exhibits eutrophication due to continuing phosphorus (P) inputs mainly from upstream nonpoint source areas. To address the Lake's eutrophication problem and as part of total maximum daily load (TMDL) requirements, a state-level P reduction goal has been set by the Department of Environmental Conservation of both Vermont and New York. Unfortunately, remedial measures being undertaken thus far to control the nonpoint P losses have been mostly based on landowner voluntary participation and have not been guided by a systematic technique to implement remedial measures where they are most needed (greater P loss risk) and where they can provide the greatest P loss reduction. Consequently, P reduction goals have not been achieved in most segments of Lake Champlain. The main objective of this study was to identify land uses with the highest P loss - i.e., critical sources areas (CSA) - using a model-based approach. Soil and Water Assessment Tool (SWAT) is used for this objective. This study focuses on the Rock River Watershed, which is one of the highest contributors of P to Lake Champlain. Spread over 71 km2, the watershed is dominated by dairy agriculture and has fertile periglacial lacustrine and alluvial soils with an old tile drainage system. Performances SWAT-prediction of hydrology, sediment, and P loss are being tested in Rock River Watershed. In this paper, outputs of model calibration, validation, and spatial locations of CSAs of runoff, sediment, and P losses are presented. The identification of CSAs for P loss is expected to support the next phase of our project, which involves exploring cost-effective P management strategies with the highest potential for P loss reduction applicable to the study watershed and Lake Champlain Basin.