Modeling The Impact of Climate Change on Dissolved Organic Carbon in The Ohio River Basin

Abstract:

Within the Ohio River Basin, a region that encompasses parts of eleven U.S. states including Ohio, Pennsylvania, Illinois, New York, and others, studies have projected that future climate change will result in changes in precipitation, streamflow, and temperature. These changes in climate will affect surface water quality, including the drinking water parameter Dissolved Organic Carbon (DOC). Since the 1980s, increasing DOC concentrations in surface waters have been observed in parts of North America and rising temperatures and increased rainfall are proposed drivers of the increase in DOC concentrations. These trends are expected to continue.

Increases in quantity and changes to the nature of DOC affect the treatability of the water for use as drinking water for the cities along the Ohio River. In particular, DOC increases the formation of carcinogenic disinfection by-products (DBPs), which are formed when organic matter reacts with disinfectants added to drinking water for microbial control. By estimating the range of future DOC concentration profiles in the Ohio River Basin, our work can inform drinking water utilities and stakeholders about the risks of increased DBP formation.

Our present work begins with the use of a range of projected temperature and precipitation data from downscaled climate models of the Ohio River Basin. We link these with a hydrologic model to project streamflow. We input projected streamflow, temperature, and precipitation data into a novel DOC model that predicts the quality and quantity of DOC. This DOC model considers the impact of a changed DOC profile on the treatability of drinking water under these future climate scenarios.