D. T. Jensen

Document Type


Publication Date

January 1978


The objective of this study is to develop a relatively simple and practical method for improving the availability and reliability of information about droughts to those responsibile for water supply management and planning. The information technique developed provides an objective basis for the selection of wate rsupply management alternatives during periods of drought. The derived drought information can assist water supply planners and managers in identifying priorities among proposed water supply developments fron consideration of water supply vulnerability and exisitng drought severity levels. Two drought indices are developed to achieve the overall objective of the study: (1) the drought severity index for describing the state of drought as it affects a water supply system and (2) the drought vulnerability index which indicates the probability of water shortage in a water supply system. In addition, the autoregressive, integrated moving average (ARIMA) method is used to develop a model representative of a water supply system and from the model synthetic data are generated using Monte Carlo methods. The synthetic data are utilized in the drought severity and vulnerability indices and the probabilities of future water shortage are calculated. In this study the drought severaity and vulnerability indices are conceptualized and tested for water supplies of three communities and three irrigation areas. Comparisons are made among the test cases. Excellent results are obtained from the municipality group and fair results are derived from the irrigation areas.