Quantifying and modelling urban stream temperature: a central US watershed study |
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Authors: | Sean Zeiger Jason A Hubbart Stephen H Anderson Michael C Stambaugh |
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Institution: | 1. Water Resources Program, Department of Forestry, School of Natural Resources, University of Missouri, Columbia, MO, USA;2. Department of Soil, Environmental, and Atmospheric Sciences, University of Missouri, Columbia, MO, USA;3. Department of Forestry, University of Missouri, Columbia, MO, USA |
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Abstract: | Hydrologic models that rely on site specific linear and non‐linear regression water temperature (Tw) subroutines forced solely with observed air temperature (Ta) may not accurately estimate Tw in mixed‐use urbanizing watersheds where hydrogeological and land use complexity may confound common Tw regime assumptions. A nested‐scale experimental watershed study design was used to test Tw model predictions in a representative mixed‐use urbanizing watershed of the central USA. The linear regression Tw model used in the Soil and Water Assessment Tool (SWAT), a non‐linear regression Tw model, and a process‐based Tw model that accounts for watershed hydrology were evaluated. The non‐linear regression Tw model tested at a daily time step performed significantly (P < 0.01) better than the linear Tw model currently used in SWAT. Both regression Tw models overestimated Tw in lower temperature ranges (Tw < 10.0 °C) with percent bias (PBIAS) values ranging from ?28.2% (non‐linear Tw model) to ?66.1% (linear regression Tw model) and underestimated Tw in the higher temperature range (Tw > 25.0 °C) by 3.2%, and 7.2%, respectively. Conversely, the process‐based Tw model closely estimated Tw in lower temperature ranges (PBIAS = 4.5%) and only slightly underestimated Tw in the higher temperature range (PBIAS = 1.7%). Findings illustrate the benefit of integrating process‐based Tw models with hydrologic models to improve model transferability and Tw predictive confidence in urban mixed‐land use watersheds. The findings in this work are distinct geographically and in terms of mixed‐land use complexity and are therefore of immediate value to land‐use managers in similarly urbanizing watersheds globally. Copyright © 2015 John Wiley & Sons, Ltd. |
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Keywords: | stream water temperature experimental watershed study urban heat island storm water runoff water quality mixed‐land use discharge |
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