ABSTRACT
Sustainable groundwater (GW) management is important to revitalize the green revolution (GR) in South Asia (SA). Together, the SA nations have over 2800 km3 or billion cubic meters (BCM) of renewable freshwater resources (Gleick 1998). The GW overdraft and unsound management strategies now threaten the sustainability of the GR in the SA region. India is the largest GW user in the world. The annual replenishable GW resources of India are 433 BCM compared with the net annual GW availability of 399 BCM and the overall GW development of 58%. The renewable water resources of India are about 4% of the global availability (IWRS 1998). More than 60% of India’s irrigated agriculture depends on GW, which was only 29% in 1950-1951 (WPB 2002). Similarly, in Pakistan, Bangladesh, and Nepal, GW is used in over 75% of the irrigated areas. At present, GW irrigation has surpassed surface (canal) irrigation as the primary source of food production and income generation in many countries of SA. GW depletion is a big problem in India and Pakistan (Postel 1999), whereas GW pollution is a major issue in Bangladesh and Nepal (Khan 1994). Due to the excessive mining of GW, the water table (WT) has been depleting by as much as 30 cm/year in northwestern India. GW pumping with electricity and diesel pump sets also accounts for an estimated 16-25 Tg of carbon (C) emission in the atmosphere. Likewise, there is also the problem of water logging and rises in the water table in some parts of India and Pakistan caused by seepage from water sources (e.g., unlined canals), excessive irrigation by ¥ooding, and lack of drainage to safely remove the excess water. The key question for policy makers, planners, and researchers is how to exploit the resource without exhausting its supply and without damaging the environment. This chapter outlines the concepts and approaches for sustainable GW use and describes the factors affecting its availability without adversely affecting the hydrogeological balance, crop production, and the environment. This chapter also discusses a range of techniques for the sustainable management of GW, including the need for rainwater harvesting (RWH) and arti‘cial recharge, and it outlines some relevant policy interventions at local and regional levels.
