INDIA'S WATER RESOURCES AND CHALLENGES

The Indian Express Online Media, March 20, 2005

India is challenged by water issues necessary for human health, economic growth, and ecological protection. Supplying a dependable, safe, and suitable water supply for multiple uses is a difficult task. Agriculture uses 80 to 90% of the water demand in India on 70 to 80 million hectares of irrigated land. In rice or paddy, India is essentially exporting water for cash. About one-fourth of the agricultural land in India is rain fed, and about three-fourths is irrigated. Of the irrigated land, surface water provides two-thirds and groundwater provides one-third of the water demand. Drinking water in rural areas (60% of the population) is supplied primarily, say 90%, by groundwater. Drinking water in urban areas (40% of the population) is supplied half by surface water and half by groundwater. Most of India's industry is located near rivers to use surface water. As per the Indian National Policy of 1986, drinking water, which is mostly groundwater, now has first priority in India. Reports suggest that groundwater is becoming even more important in providing sustainable drinking water and irrigation water in India, especially in rural areas and during drought or dry periods. Actions to improve groundwater management through artificial recharge, improved irrigation scheduling and cropping patterns are the needs of the day. Groundwater may limit its use in crop production and as a safe drinking water source without treatment or dilution. Many crops are sensitive to salinity, sodium adsorption ration, and trace metals, while drinking water must meet standards in several parameters, including total dissolved solids, heavy metals, arsenic, fluoride, nitrates, agricultural chemicals, and pesticides. Several central and state studies have already been conducted in India on the distribution of these chemicals in groundwater. Water for all To improve groundwater management by assessing, remediating, and communicating water quality threats, these activities should be considered: * Training through workshops * Community and contractor outreach * Technical assistance and technology transfer * Focus on crop, human health, and environmental (ecological) risk assessment * Mapping of groundwater quality using geographic information system * Remediation action planning, such as monitoring and restricting use, dilution, and treatment The great river valleys of the subcontinent sometimes contain groundwater that naturally contains high levels of arsenic, which is unhealthy for people and the environment though it is natural with some human modification as well. Under these circumstances, subcontinent groundwater should be examined to identify high-arsenic areas so that they can be either avoided, or its groundwater collected for centralised or at-well-head treatment to reduce the human health and environmental risks, and associated economic opportunity losses. Arsenic in subcontinental groundwater is associated with pyrite and other sulphide minerals. Such minerals are formed in low pH or highly acidic, reducing (oxygen deficient) natural depositional environments. As these minerals naturally weather, or are attacked by native, ambient, and introduced microorganisms often associated with human wastewater and irrigation return flows, they release arsenic as a dissolved constituent in groundwater, making it biologically available. Arsenic in groundwater can be readily treated relatively inexpensively by oxygenation, carbonation, reduction, coagulation, precipitation, ion-exchange, or activated carbon filtration, and is especially cost-effective if groundwater is not heavily saline, turbid, or contaminated with organic matter. Arsenic, an established carcinogen, in groundwater above the WHO maximum permissible limit of 0.05 milligram per litre (parts per million) has been found in six districts of West Bengal. More than 8,00,000 people are drinking arsenic contaminated water and amongst them at least 1,75,000 people show arsenical skin lesions. Hair, nails, scales, urine, liver tissue analyses show elevated concentrations of arsenic in people drinking arsenic-contaminated water for a longer period. The author is a resources and environmental management consultant, Washington, DC