Water Quality Challenges in Ganga Basin, India

Abstract

The river Ganga has a very important economic, environmental and cultural value in India. With fast growth in population and economy in the Ganga Basin the water use has intensified many fold. With highly uneven distribution of rainfall in the basin, it is experiencing severe water scarcity in many parts. Basin’s groundwater is over-abstracted leading to lowering of water table at alarming rate which resulted in reducing the flows of most of the tributaries of the Ganga. With fast urbanization and increasing prosperity the wastewater is steeply increasing. Due to paucity of resources the urban local bodies, which are responsible for management of this wastewater, are not able to do so. Thus, a large part of this wastewater is getting into the river Ganga or its tributaries either untreated or partially treated. Reduced level of water flow coupled with increased waste loads pose serious water quality problems in the river. Although, access to drinking water has increased over the past decade due to large number of efforts by the government, still the tremendous adverse impact of unsafe water on health continues. The highest mortality from diarrhoea is said to be among children under the age of five, highlighting an urgent need for focused interventions to prevent and control water quality degradation to avoid diarrhoeal disease.

The water quality monitoring results indicated that pathogenic pollution caused by discharge of untreated or partially treated domestic wastewater is the main cause of water quality degradation in the Ganga river. Most of the tributaries of the Ganga and many groundwater sources are affected by such pollution. Apart from pathogenic pollution organic pollution causing oxygen depletion was observed in many stretches of the Ganga and its tributaries. Nutrient enrichment followed by eutrophication is observed in some stretches of the Ganga and its tributaries. Toxic pollution is observed in some pockets of the river or its tributaries, where industries are concentrating. Due to lack of proper transport facilities (sewerage system) for the wastewater in the basin both for domestic and industrial wastewater, a large part of it is percolating in the ground and polluting the groundwater. Such pollution is evident in large urban and industrial areas. The over-exploitation of groundwater in many parts of the basin led to geogenic contamination by underground minerals. Fluorides, iron, arsenic, salinity and hardness is found to be increasing in many parts of the basin.