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LAND USE AS A MITIGATION STRATEGY FOR THE WATER QUALITY IMPACTS OF GLOBAL WARMING: A SCENARIO ANALYSIS ON TWO WATERSHEDS IN THE OHIO RIVER BASIN
Citation:
Liu, A. J., J A. Goodrich*, AND S. Y. Tong. LAND USE AS A MITIGATION STRATEGY FOR THE WATER QUALITY IMPACTS OF GLOBAL WARMING: A SCENARIO ANALYSIS ON TWO WATERSHEDS IN THE OHIO RIVER BASIN. Presented at 4th Int Conf on Integrating GIS and Environmental Modeling: Problems Prospects and Research Needs, Banff, Alberta, Canada, 9/2-8/2000.
Description:
This study uses an integrative approach to study the water quality impacts of future global climate and land use changes. In this study, changing land use types was used as a mitigation strategy to reduce the adverse impacts of global climate change on water resources. The climate scenarios were based on projections made by the Intergovernmental Panel on Climate Change (IPCC) and the United Kingdom Hadley Centre's climate model (HadCM2). The Thornthwaite water balance model was coupled with a land use model (L-THIA) to investigate the hydrologic effects of future climate and land use changes in the Ohio River Basin, The land use model is based on the Soil Conservation Service's curve number method. It uses the curve number, an index of land use and soil type, to calculate runoff volume and depth. The ArcView programming language, Avernue, was used to integrate the two models into a GIS. An output of the water balance model, daily precipitation values adjusted for potential evapotranspiration, served as one of the inputs into the land use model. Two watersheds were used in the present study: one containing the city of Cincinnati on the mainstem of the Ohio River, and one containing the city of Columbus on a tributary of the Ohio River. These cities represent two major metropolitan areas in the Ohio River Basin with different land uses experiencing different rates of population growth. The projected hypothetical land use changes were based on linear extrapolations of curent population data. Results of the analyses indicate that conversion from agricultural land use to low-density residential land use may decrease the amount of surface runoff. The land use practices which generate the least amount of runoff are forest, low-density residential, and agriculture; whereas high-density residential and commercial land use types produce the highest runoff. The hydrologic soil type present was also an important factor in determining the amount of runoff and non-point source pollution. A runoff depth matrix and total nitrogen matrix were created to describe possible land use mitigation measures in response to global climate change. The results of this study may be useful to planners and policy makers for defining the possible impacts of future global climate and land use changes on water resources.