The Water Balance of the World's Continents and a Balance Estimate of the World's Freshwater Resources

The results of several years of investigation of the water balance of continents and the world's freshwater resources are presented. Through the use of interpolation relationships to make up for data gaps, maps are compiled for the basic elements of the water balance of the world: total runoff, including its surface and subsurface components, evaporation, gross wetness (soil moisture) and the coefficient of subsurface alimentation of streams, which reflects much of the stable component of streamflow. Revised estimates for the water-balance elements are offered for continents on the basis of revised data. The per capita water supply of continents is calculated, with separate listing of the stable component of runoff, consisting not only of the subsurface flow to streams but also the portion of surface streamflow that is regulated through lakes and reservoirs.