Water-supply Management 222 Water resources development 191 Water 66 Water quality management 57 Environmental aspects 43 Economic aspects 38 Purification 35 Government policy 33 International cooperation 30 Hydrology 29 Sustainable development 28 Water-supply engineering 28 Sewage 22 Climatic changes 20 Sewage disposal 20 Water utilities 20 Case studies 18 Groundwater 17 Water quality 17 Integrated water development 16 Congresses 14 Drinking water 14 Distribution 13 Hydraulics 13 Municipal water supply 13 Pollution 13 Water conservation 13 Water use 13 Watershed management 13