Development of critical period forecasting model for Mun Bon reservoir

The critical period forecasting model of Mun Bon reservoir was developed. The lengths of hydrological records of 20, 30 and 48 years and 30 synthetic data series were used. In this study, the various demand ratio of 10%, 25%, 50%, 60%, 75%, 87% and 100% of annual inflow were assumed and then reservoir operation were simulated by using water balance approach. The critical period of reservoir was analyzed and the reservoir performance index in term of reliability and resiliency were evaluated. The simulated result were used to develop the critical period forecasting model in form of linear and non linear regression model in order to the output of forecasted critical period was correct. The result showed that the higher demand ratio provided the higher critical period length of reservoir and the length of data of 48 years gave the highest critical period. In addition, when the annual demand of these system was 60% of annual inflow, it gave the highest reliability and resiliency. This showed that the reservoir operations were quite reliable and the ability of the system to recover from the failure mode (shortage and spillage) was rather good. The critical period forecasting model of Mun Bon reservoir was the function of demand ratio, reliability and length of record. The performance of the forecasting model was quite well with R ² of 0.97.