Brief notes on the Water strain Areas of India

If we superimpose the maps of groundwater potential and its utilisation in drought prone and desert areas water-strain areas may be identified. Maharashtra, Western Rajasthan, major parts of Gujarat, interior Karnataka, Tamil Nadu and interior of southern Andhra Pradesh have assured groundwater resources for domestic and irrigational use. In such areas, surface water resources in terms of river flow and small surface reservoirs are undependable and highly restricted.

The groundwater thus becomes the main reliable source of water supply. Here, the depletion of ground and surface water in some places due to climatic factors and rapidly increasing population has resulted in lowering of groundwater table and creation of water shortage posting drinking water scarcity.

Lowering of groundwater table due to unchecked and negligent exploitation of this precious resource is posing great threat to the geo-environment in the form of salty seawater intrusion in some coastal areas. There are no appropriate legislations on the controlled uses of this common property.

Groundwater Quality

More or less, all towns and villages in India heavily depend for their drinking water supply on groundwater. Groundwater pollution is less visible but often more serious, because it takes decades for polluted aquifers to clean.

Pollution of groundwater is caused by many factors. A few of them are summarized here as under:

(i) Pollution is caused by waste generated from different sources – urban, agricultural and industrial sectors. It is estimated that municipal sewage alone accounts for 80 per cent of polluting influence in our country. Sewage discharges heavy metals, synthetic chemicals and other hazardous wastes.

(ii) Sometimes, industrial effluents are directly discharged into groundwater.

(iii) Agricultural effluents mainly arising from excessive use of chemicals may pose a major threat to groundwater quality due to contamination of ammonia, nitrates and pesticides.

(iv) Dumping of city waste at landfills followed by rains cause heavy damage to groundwater quality. Acid rains also cause groundwater pollution.

(v) Industrialization coupled with intensive farming is posing serious danger to groundwater.

(vi) Inadequate sanitation is another important cause of groundwater pollution.

(vii) Uncontrolled and rapacious exploitation of this resource is mainly responsible for depletion in certain areas.