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River water quality response under hypothetical climate change scenarios in Tunga-Bhadra river, India

Rehana, S and Mujumdar, PP (2011) River water quality response under hypothetical climate change scenarios in Tunga-Bhadra river, India. In: Hydrological Processes, 25 (22). pp. 3373-3386.

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/hyp.805...

Abstract

Analysis of climate change impacts on streamflow by perturbing the climate inputs has been a concern for many authors in the past few years, but there are few analyses for the impacts on water quality. To examine the impact of change in climate variables on the water quality parameters, the water quality input variables have to be perturbed. The primary input variables that can be considered for such an analysis are streamflow and water temperature, which are affected by changes in precipitation and air temperature, respectively. Using hypothetical scenarios to represent both greenhouse warming and streamflow changes, the sensitivity of the water quality parameters has been evaluated under conditions of altered river flow and river temperature in this article. Historical data analysis of hydroclimatic variables is carried out, which includes flow duration exceedance percentage (e.g. Q90), single low- flow indices (e.g. 7Q10, 30Q10) and relationships between climatic variables and surface variables. For the study region of Tunga-Bhadra river in India, low flows are found to be decreasing and water temperatures are found to be increasing. As a result, there is a reduction in dissolved oxygen (DO) levels found in recent years. Water quality responses of six hypothetical climate change scenarios were simulated by the water quality model, QUAL2K. A simple linear regression relation between air and water temperature is used to generate the scenarios for river water temperature. The results suggest that all the hypothetical climate change scenarios would cause impairment in water quality. It was found that there is a significant decrease in DO levels due to the impact of climate change on temperature and flows, even when the discharges were at safe permissible levels set by pollution control agencies (PCAs). The necessity to improve the standards of PCA and develop adaptation policies for the dischargers to account for climate change is examined through a fuzzy waste load allocation model developed earlier. Copyright (C) 2011 John Wiley & Sons, Ltd.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to John Wiley & Sons.
Keywords: river water quality;climate change impacts;hypothetical scenarios;fuzzy waste load allocation model
Department/Centre: Division of Earth and Environmental Sciences > Divecha Centre for Climate Change
Division of Mechanical Sciences > Civil Engineering
Date Deposited: 17 Nov 2011 09:00
Last Modified: 17 Nov 2011 09:00
URI: http://eprints.iisc.ernet.in/id/eprint/42065

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