Probabilistic estimation of water shortage of various lead times for a water-supply reservoir

Abstract

Inefficient uses of water resources in Taiwan are caused by uneven distributed rainfall and steep terrain Reservoirs become important facilities to regulate highly fluctuating streamflow and provide stable water supplies in Taiwan The purpose of this study is to theoretically derive water-shortage probabilities and distributions of future lead times for a water-supply reservoir The reservoir supply ability is represented by water availability which is defined as the sum of useful storage and inflow The water-shortage probability is the probability when the demand is less than the water availability The water-shortage distribution is a flip of the water-availability distribution The Nanhua Reservoir and the Chiahsien Weir located in southern Taiwan is used as an example to illustrate the proposed methodology The water-shortage probabilities and distributions of 1 to 18 10-day periods for various initial useful storage (from empty to full capacity) are constructed The results indicate that the water-shortage probabilities are different in various periods which reflect inherent differences of inflow distributions The water-shortage probabilities generally decrease with increasing initial useful storage for the same lead time Furthermore the water-shortage distributions leftward shift distributed in a smaller range with increasing initial useful storage The proposed methodology is useful for real-time reservoir operation since it provides decision-makers future lead-time water-shortage probability and distribution for triggering water rationing measures

Date of Award	2020
Original language	English
Supervisor	Jenq-Tzong Shiau (Supervisor)