A Modelling Approach for Water Quality Assessemnt of Pili River using Hec-Ras

摘要

Nagpur, the winter capital of Maharashtra, is the largest city of Central India. It is one of the major cities that come under the proposed smart city project undertaken by the Government of India. But with the advent of urbanisation in the city over a past few years the demand for water has significantly increased. On the other hand, there has been a decrease in the quality of water, especially in the Piliriver, to a great extent due to establishments around it and discharges of untreated domestic sewage. Pili originates from the Gorewada lake, which is one of the major sources of drinking water to the city. Due to many anthropogenic activities in and around it, the river has lost all its natural biodiversity and has, in fact, turned into a drain (Nag river Basin Plan, 2011). Hence there is a need for studying the quantity and the quality of the river water to assess its uses for drinking and other purposes. Also an attempt to restore the quality of river water back to its original condition can be made based on the hydrodynamic and water quality simulation using HEC-RAS. The model uses explicit numerical scheme to solve one-dimensional advection-dispersion equation. Water quality simulation was carried out for average dry weather flow under existing river geometry. The results of the water quality simulation provided spatial as well as time series variation of the parameters that are considered for formulating various management and treatment options. The results of the simulated data can be used for close monitoring of the parameters which are the main cause for the degradation of the quality of water in the different stretches of the river. Based on the simulation results, various engineering solutions like decentralized sewage/wastewater treatment, in-stream treatment etc. are suggested for improvement in the river water quality especially to polluted stretches and drains contributing pollution in the river.