The Latin American and Caribbean countries have seen growing pressure on water resources, with increasing demand and costs, for agricultural, domestic and industrial consumption. This has brought about the need to maximize and augment the use of existing or unexploited sources of freshwater. There are many modern and traditional alternative technologies for improving the utility and augmenting the supply of water being employed in various countries, but with limited application elsewhere due to the lack of information transfer among water resources managers and planners. This sourcebook was prepared by the Unit of Sustainable Development and Environment of the General Secretariat of the Organization of American States (OAS) as part of the joint United Nations Environment Programme (UNEP) Water Branch and International Environmental Technology Centre (IETC). Its main purpose is to provide information on technologies for the augmentation of freshwater resources. It is expected to especially benefit water resources managers and planners in Latin America and the Caribbean by enabling them to make informed choices, thereby optimizing the use of available freshwater resources and augmenting these resources using technologies appropriate to Latin America and the Caribbean.