Impacts of Climate Change on Ganga River Water Quality in the Kanpur Region

Abstract:

Large industrial discharge along with high agricultural runoff and untreated sewage disposal makes the Kanpur region a highly polluted stretch of Ganga river. With rigorous initiatives now underway to clean the river, it becomes necessary to examine the implications of climate change on the river pollution. In a previous study, we investigated the climate change impact on water quality of Ganga river for Kanpur stretch using eight hypothetical climate change scenarios of varying air temperature and stream flow. The Water Quality simulation model QUAL2K was used for simulating Dissolved Oxygen (DO), Biochemical Oxygen Demand, ammonia, nitrate, total nitrogen, organic-, inorganic- and total phosphorous and faecal coliform. Results showed that water quality parameters are more sensitive to the amount of stream flow as the concentration of water quality parameters increased with reduction in stream flow. Except DO, other water quality parameters improved with increase in temperature due to high reaction kinetics at higher temperatures. The water quality parameters at the critical locations were found to be not within safe limits and the entire stretch was found eutrophic for the hypothetical future climate change scenarios that were considered. In this present study, an improved and more realistic approach is used to quantify climate change impacts on water quality in the same region. Fig 1 shows the schematic diagram of the methodology adopted. An ensemble of 21 General Circulation Models (GCM) for RCP 4.5 and RCP 8.5 scenarios for the year 2040-60 will be used. The hydrologic model HEC-HMS and hybrid model Air2stream will be integrated with the water quality model QUAL2K which was used in the earlier study. Results from this new study would be presented at the meeting and we believe our results would provide useful guidance to the policy makers and pollution control authorities for taking necessary actions to control Ganga river pollution in the future climate change scenarios.