Abstract
A stochastic estimation of drought evaluation in the upper reaches of streams is needed in the planning of development and management for water resources and/or water use. In this paper, a procedure for the construction of a stochastic flow duration curve is presented, and is applied to five dam basin areas located in eastern Japan. Though daily discharge data of a given N year term extracted at various points on the flow-duration curve is usually fitted closely by a log-probability distribution, some of the annual minima of daily discharge are fitted by Weibull's probability paper. The effectiveness of this technique for drought evaluation is illustrated through its application. The drought discharge (355 days discharge) is expected to be one index of drought evaluation. Moreover the shape of the flow duration curve is discussed.
