Evaluation of Surface, Ground and Sewage Water for Sustainable Supply of Potable Water to Bengaluru

Abstract

Bengaluru which was only 29 sq. km in the beginning of last century has grown beyond the limits laid down by Kempegowda II to 1275 sq. km. The population has also increased from 1.63 lakhs in 1901 to 84.90 lakhs in 2011 and is expected grow to 205.61 lakhs by 2051. Bengaluru Water Supply and Sewerage Board (BWSSB) is presently pumping 1400 MLD across four stages from Cauvery river for about a distance of 100 km over a height of 300 m, is an unique example in the world. Karnataka State had sought 792.87 MCM (28 TMC) of Cauvery water for domestic and industrial use in urban and rural areas of Bengaluru. Cauvery tribunal awarded of a total of 17.22 TMC of which 50% is considered as available from surface water and allowed 247.77 MCM (8.77 TMC) in a year for Bengaluru city – rural and urban. With the inauguration of 500 MLD Cauvery water supply project stage IV, phase-II on 31.10.2012 by Chief Minister of Karnataka the allocated water of 19 TMC to the city has been completely utilised under the Cauvery Tribunal Award. According to an estimate the demand for water in the city may rise to 2550 MLD by the year 2036 and the city could face a shortage of 1000 MLD. Government of Karnataka is exploring possible alternative resources for short, medium and long term supplies on sustainable basis. The views expressed by the Geological Society of India (GSI) through its publications highlighting the importance of rainwater harvesting and treatment of waste water as alternative sustainable resources for Bengaluru city are summarized below.