Huron-Erie Corridor: Meeting watershed P loading targets

Session: Great Lakes Tributaries: Connecting Land and Lakes (3)

Awoke Dagnew, Environmental Consulting and Technology, [email protected]
Donald Scavia, University of Michigan, [email protected]
Yu-Chen Wang, University of Michigan, [email protected]
Rebecca Muenich, Arizona State University, [email protected]
Margaret Kalcic, Ohio State University, [email protected]

Abstract

The water quality of Lake Erie is influenced by phosphorus loads from the ~19,000 km2 Huron-Erie Corridor watershed. We used the Soil and Water Assessment Tool (SWAT) to evaluate a range of management practices scenarios to potentially reduce total phosphorus (TP) and dissolved reactive phosphorus (DRP) loads. Single practice scenarios included fertilizer rate reduction (Rate) and sub-surface placement (PL), filter strips (FL), grassed waterways, cover crops (CC), wetlands (WT), controlled drainage, and changes in tillage practices. Bundle scenarios included combinations of Rate, PL, FL, CC, and WT with three adoption strategies: application on all applicable areas, on 55% of randomly selected applicable areas, and on 55% of high phosphorus yielding applicable areas. Results showed that among the single practice scenarios, FL, WT, PL, CC, and Rate performed well in reducing both TP and DRP loss from agricultural dominated sub-watersheds. Over all, the CC, FL, WT bundle performed best, followed by the CC, PL, WT bundle, reducing the load up to 80% and 70%, respectively, with 100% implementation. However, targeting high phosphorus yielding areas performed nearly as well as 100% implementation. Results from this work suggested that there are potential pathways for phosphorus load reduction but extensive implementation of multiple practices is required.