Groundwater Salinity in Northwestern Region of India: A Critical Appraisal

Abstract

Groundwater plays a pivotal role in India, particularly in hard rock and semi-hard rock regions of the country to support domestic, agricultural, and industrial requirements of water in addition to environmental needs. Rising demands of groundwater for rapidly increasing population, developmental activities and urbanization have resulted in unsystematic over extractions of groundwater that led to the decline of groundwater levels in many parts of the world including India. Many areas have even no proper groundwater development program that has given rise to problems of waterlogging and salinity. Approximately, 25% area of the Indo-Gangetic basin has saline water with TDS more than 1000 mg/L (as per WHO 2004) or conductivity more than 1500 μS/cm. In Indo-Gangetic basin, the problems of salinity in Indus and upper Gangetic parts covering northwestern states of India are different than the salinity of coastal areas. The major problem of groundwater salinity in the northwestern states, namely Delhi, Haryana, Punjab, and Rajasthan, is of terrestrial origin. The order of salinity affected state, in terms of magnitude, is Rajasthan > Haryana > Punjab > Delhi. Over-abstraction of groundwater can also spread saline water into the freshwater zones due to the presence of evaporative sequences from deeper to shallower depths.Modern irrigation practices with dense canal distribution network may lead to very shallow water tables, hence may increase waterlogging and salinization due to the leakage. The impacts of groundwater salinity largely hamper the crop productivity and thereby can affect the food security. Management of groundwater salinity is thus essential for the sustainability of food security and to remediate health hazards and ecosystem services in the northwestern region of India. To obviate the problem and for better management of groundwater resources in the area, one has to know the interaction between the aquifers and surface water sources.