Estimation of yields from river basins by a modification of the water balance procedure of thornthwaite

Abstract

Stream-flow is one of the most important of hydrologic measurements, for, it represents the total runoff from a basin and is the resi-dual of precipitation after the demands of eva-potranspiration and soil storage are met. The need for runoff data in different parts of the world is increasing so rapidly that the existing network of stream-gauge stations is either too sparse or has an inadequate period of record. An alternative approach from meteorological data was, therefore, suggested by Thornth-waite (Thornthwaite 1948) whose book-keep-ing procedure for water balance offers a method for the determination of runoff on a monthly basis. The basis of this method as well as other water balance methods is that closed chain of events representing the circulation of water in the atmosphere and over the earth, known as the hydrologic cycle, which constantly redistributes water between the earth's surface and the atmosphere, tending to main-tain a long term balance.