Theme 3-17-Water quality modelling studies of river Ganga in the Kanpur stretch - Estimation of non-point sources

Abstract

The present study objectively analyzes the state of water quality (in terms of DO-BOD) in the Kanpur stretch of river Ganga and assesses the non-point sources and their impact by employing water quality modeling. The Enhanced Stream Water Quality Model (QUAL2E) of USEPA has been used in this study.

A stretch of 31-kilometer (starting from a few kilometers upstream of Kanpur) was covered and on the spot water quality sampling and analysis was carried out at various locations to generate the required database for model calibration/validation. The data on various point load discharges were collected in terms of flow and water quality characteristics.

Initially the model predicted a better water quality than the quality observed on the field. This mismatch was attributed to the undefined non-point sources of waste discharges. Efforts to calibrate the model estimated the non-point sources in terms of BOD load as about 15700 kg/day and high Sediment Oxygen Demand (SOD). It was observed during field survey that the pollution from non-point sources (e.g. small drains, solid waste disposal etc.) was wide spread along the river. Thus, as a major recommendation of this research, it was concluded that unless non-point sources are controlled, the desired water quality levels cannot be achieved.