1-DIMENSIONAL MODELING USING QUAL2K FOR GANGA RIVER IN UTTARAKHAND

Abstract

Stream simulation or modeling is a cost-effective way for water quality monitoring and predicting the future quality of rivers and streams. The water quality models are very useful tools for simulation, prediction, and management of the water bodies through assessing the water quality and detecting the level, distribution, and risks of chemical pollutants due to the release of untreated sewage waste into the water bodies. To assess the status of aquatic ecosystems, impacts of pollution load from various sources, and control of water pollution under varying flow conditions, different water quality models are emerging as a strong decision-supporting tool. Assessment of hydraulic and water quality conditions under different developmental and changing scenarios is a prerequisite for planning and management activities of any river basin. Thus, the design of water quality models should be such that there can be a good agreement between observed and model values and can able to predict the planning scenarios which may be significantly different from observed conditions. In this work, Qual2K modeling software is employed for the assessment of changes in surface water quality. The model is used to study the stretch of river Ganga from Devprayag to Bijnor (166 km) by comparing the results of February – March 2020 and February – March 2021. The model is simulated by considering many parameters of meteorological, topographical, hydraulic, hydrological, and water quality parameters. The modeling results can help in the analysis of the water quality and the circumstances that arise due to the release of sewage discharge, industrial effluent, runoff from agriculture, forests, urban and rural settlements, etc., into the river during the period. The work has been carried out in Qual2K by following steps – segmentation of river, input of available data from different sources CPCB - NWMP, SPCBs, IMD, etc., simulation of model by adjusting kinetics rates and coefficients, calibration of model , validation of model, analysis of results, and comparison of the different months scenarios. GIS software has been used for the preparation of thematic maps for the study area for water quality classification, point source pollution, and diffuse source pollution.