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

Abstract

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.

River discharge, land use change, and surface water quality in the Xiangjiang River, China

“…As for water quality parameters, TN, NH 3 –N, COD, TP, BOD 5 , and DO were more affected by river discharge than the other parameters (Figure ). Higher DO values during low‐flow periods than during high‐flow periods are reasonable since the air temperature is lower during low‐flow periods, which has also been demonstrated in India (Rehana and Mujumdar, ). However, many other studies have emphasized the dependence of DO on discharge for a wide range of water bodies in different climatic regions (Marcé et al ., ; Huang et al ., ; Rixen et al ., ).…”

Effects of climate change on stream temperature, dissolved oxygen, and sediment concentration in the Sierra Nevada in California

“…[7] Studies on the effects of climate change on stream DO and sediment concentrations are scarce within the literature. Several water quality modeling studies suggest a depletion of DO concurrent with future increase in water temperatures for basins in Europe and India [Carmichael et al, 1996;Cox and Whithead, 2009;Rehana and Mujumdar, 2011]. Simulations have shown [Pruski and Nearing, 2002;Ficklin et al, 2010] that increases in total rainfall are likely to increase sediment erosion and sediment loads in rivers, while temperature increases without concurrent precipitation changes resulted in decreases in sediment loads.…”

Surface water quality in a sulfide mineral‐rich arid zone in North‐Central Chile: Learning from a complex past, addressing an uncertain future

“…Although there is abundant literature on the impact of climate change/climate variability on the hydrological behaviour of river basins (e.g., Bartnett, Adam, & Lettenmaier, 2005;Leavesley, 1994;Milly, Dunne, & Vecchia, 2005), the effects on water quality have been studied to a much lesser degree (Glavan, Ceglar, & Pintar, 2015;Kundzewicz et al, 2008;Rehana & Mujumdar, 2011;Van Vliet & Zwolsman, 2008;Whitehead, Wilby, Battarbee, Kernan, & Wade, 2009). Nonetheless, it is interesting to note the work of Whitehead et al (2009), which presents an overall summary of the probable effects of climate change on different pollutants, with a focus on the United Kingdom.…”