Assessment of Water Resources and Water Availability in the World

by Igor A. Shiklomanov, State Hydrological Institute, Russian Federation

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This report serves as a primary technical document source for Section 1 of the Comprehensive Freshwater Assessment. It contains an estimate of the water storage on the Earth including fresh and salt water, the amount and distribution of the freshwater renewable resources, and estimates of past, present and future water withdrawals and consumption by sector. The report also contains specific information on water quality and its implications for human health, and the use, and overuse, made of groundwater to meet the ever growing needs of the world's population

An evaluation is made of water availability per capita and regions of the world are identified where the present and future disparity between uses and renewable water supply will be the greatest. Future demand will be greatest in the developing countries because of population growth, and increasing agricultural and industrial sector utilization.

The report details the extreme difficulty in preparing a global assessment because of the lack of sufficient and reliable information on water availability, its quality, and water use in many areas of the world. Efforts to balance supply and demand, and plans for a sustainable future are severely hampered by this lack of information. International action is required to overcome these limitations, and assist those countries most in need to reach self-sufficiency in terms of reliable information and the capability to carry out water resource assessments and manage their water and related resources in a sustainable fashion.