Modeling the effects of climate change on water, sediment, and nutrient yields from the Maumee River watershed

Study region: Harmful algal blooms (HABs) in the Western Basin (WB) of Lake Erie have been linked to nonpoint pollution from agricultural watersheds. The Maumee River watershed is the largest in the Great Lakes region and delivers the biggest sediment and nutrient load to Lake Erie. Study focus: Climate change could alter the magnitude and timing of sediment and nutrient delivery to Lake Erie's WB. Data from four Coupled Model Intercomparison Project Phase 5 (CMIP5) models were inputted into a calibrated Soil and Water Assessment Tool (SWAT) model of the Maumee River watershed to determine the effects of climate change on watershed yields. Tillage practices were also altered within the model to test the effectiveness of conservation practices under climate change scenarios. New hydrological insights for the region: Moderate climate change scenarios reduced annual flow (up to -24%) and sediment (up to -26%) yields, while a more extreme scenario showed smaller flow reductions (up to -10%) and an increase in sediment (up to +11%). No-till practices had a negligible effect on flow but produced 16% lower average sediment loads than scenarios using current watershed conditions. At high implementation rates, no-till practices could offset any future increases in annual sediment loads, but they may have varied seasonal success. Regardless of future climate change intensity, increased remediation efforts will likely be necessary to significantly reduce HABs in Lake Erie's WB. (C) 2015 The Authors. Published by Elsevier B.V.