Effects of Climate Change on Maumee River Basin Hydrology and Nutrient Runoff

Download or read book Effects of Climate Change on Maumee River Basin Hydrology and Nutrient Runoff written by Andreas Mitsutoshi Culbertson and published by . This book was released on 2015 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change poses a serious threat to Lake Erie, as global climate models (GCMs) project increases in the amount and intensity of rainfall in surrounding watersheds which may increase flow and nutrient loading into the lake. Quantifying these potential changes is necessary to develop management recommendations to preserve Lake Erie ecosystem services in the future. This study utilized the process-based SWAT hydrologic model and an ensemble of global climate models to study the potential effects IPCC RCP4.5 (mid-range) and RCP8.5 (high) emissions scenarios on the Maumee River discharge and nutrient loading rates through the 21st century. Generally, the impacts of climate change on flow, sediments and nutrients discharged from the Maumee River become more pronounced moving from the near- (2010-2039) to the mid- (2040-2069) and far-century (2070-2099). Increased winter temperatures are expected to result in fewer snowmelt events and greater infiltration, greatly reducing winter surface runoff, sediment, and phosphorus loading. Spring time (March-June) flow, which is highly correlated with Lake Erie harmful algal blooms (HABs), was projected to increase 4.4% (0.2%) in the near-century and 6.1% (12.1%) by the late-century under RCP4.5 (RCP8.5) due to increases in precipitation and reduction in plant stomatal conductance. These increases in flow are expected to result in increased spring sediment loading by 2.6 (0.4%) in the near-century and 8.0% (36.0%) by the late-century under RCP4.5 (RCP8.5). Fall (September-November) discharge was greatly impacted by increased precipitation and projected early harvests, which resulted in prolonged periods of bare fields and susceptibility to erosion. Fall sediment increased 23.3% (17.1%) and soluble reactive phosphorus (SRP) increased 17.9% (12.9%) in the near-century, continuing into the far-future, where sediment increased 40.7% (72.2%) and SRP increased 25.7 (43.1%) under RCP4.5 (RCP8.5). Because of increased plant growth and phosphorus uptake driven by elevated carbon dioxide levels, as well as reduced winter surface runoff, annual SRP decreased by 0.7% (3.7%) in the near-century and 11.2% (7.2%) by the far-century, and annual total phosphorus (TP) decreased by 4.0% (6.5%) in the near-century and 14.1% (6.0%) by the far-century under RCP4.5 (RCP8.5). These findings demonstrate that despite projected increases in flows and sediment yields, increased plant growth stimulated by elevated carbon dioxide levels may potentially cause reductions in Maumee River phosphorus loading during the 21st century.