Regional Management of Water Resources (Proceedings of a symposium held during the Sixth IAHS Scientific Assembly at Maastricht, The Netherlands, July 2001). IAHS Publ. no. 268, 2001. 65 Integrated approach for water resources management in the Delhi region: problems and perspective p. s. DATTA Nuclear Research Laboratory, Indian Agricultural Research Institute, New Delhi 110012, India e-mail: psdatta@iari.ernet,in S. K. ROHILLA NCR Planning Board, India Habitat Centre, New Delhi, India S. K. TYAGI Nuclear Research Laboratory, Indian Agricultural Research Institute, New Delhi 110012, India Abstract Different parts of Delhi region face water scarcity due to fast rising population, industrialization, zonal disparity in water supply and competition for economic development. The fact that water sources are highly polluted and inadequate, subsidies for domestic consumption are very high, and no pricing exists for groundwater extraction, leads to more consumption and wasteful utilization of water. Indiscriminate groundwater exploitation has resulted in a widespread decline in the water table and intermixing of fresh and contaminated water. Contemporary recharge from rainfall is small, and the major contributors to the groundwater are lateral flow from surrounding areas, infiltration of agricultural/urban runoff and seepage from the canal/river. The choice lies between tapping a minimal renewable resource or exploiting a non- renewable resource till exhausted. Water management must be linked with changing land use, harmonizing medium and long-term actions, balancing and restricting indiscriminate groundwater withdrawal by recharge, improving the operation and maintenance of the water distribution network, and capacity building of local people. Key words integrated water management; Delhi region; water scarcity; groundwater exploitation; pollution problems INTRODUCTION hi the semiarid Delhi region, due to rapid urbanization, industrialization and competition for economic development, the desire for adequate supply of good quality water is in- creasing among the population, which increased from 1.7 million in 1951, to 4.1 million in 1971, 9.4 million in 1991, 13.4 million in 1999, and is estimated to grow to over 19.5 million by 2011 (NCRPB, 1999). During 1981-1991, almost 50% of the population growth was due to migrants; over 70% of these were from the neighbouring states of Uttar Pradesh, Haryana and Rajasthan (NCRPB, 1999). Of the total area (1485 km 2 ), the urban area and built-upon rural area account for about 750 km 2 of which almost 45% is rural area, having 258 settlements including 29 census towns (NCRPB, 1999; Rohilla et al., 1999). By 2001, 71 more settlements are expected under the urban extension. Throughout every year, particularly during the summer months of May and June, when the temperature exceeds 40°C, different parts of the area face acute water scarcity,