Climate Sensitivity of Phosphorus Loadings to an Urban Stream |
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| Authors: | Kate M Munson Richard M Vogel John L Durant |
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| Affiliation: | 1. Department of Environmental Science, Gradient Corporation, Cambridge, Massachusetts;2. Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts |
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| Abstract: | We investigate the sensitivity of phosphorus loading (mass/time) in an urban stream to variations in climate using nondimensional sensitivity, known as elasticity, methods commonly used by economists and hydrologists. Previous analyses have used bivariate elasticity methods to represent the general relationship between nutrient loading and a variable of interest, but such bivariate relations cannot reflect the complex multivariate nonlinear relationships inherent among nutrients, precipitation, temperature, and streamflow. Using fixed‐effect multivariate regression methods, we obtain two phosphorus models (nonparametric and parametric) for an urban stream with high explanatory power that can both estimate phosphorus loads and the elasticity of phosphorus loading to changes in precipitation, temperature, and streamflow. A case study demonstrates total phosphorus loading depends significantly on season, rainfall, combined sewer overflow events, and flow rate, yet the elasticity of total phosphorus to all these factors remains relatively constant throughout the year. The elasticity estimates reported here can be used to examine how nutrient loads may change under future climate conditions. |
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| Keywords: | climate elasticity multivariate nutrients nutrient loading nonpoint source pollution streamflow phosphorus water quality |
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