Drought Monitoring Assessment Using a Probabilistic Approach and a Combinational Reservoir Index (MSUI)

Assignment of appropriate indices constitutes an important component of a monitoring system necessary for the planning of drought encounter plans. The probabilistic approach and the combinational reservoir index methods were assessed and compared, to monitor the drought period of 1998-2000 in Zayandeh Rud basin. To follow the purpose, the MSUI index was initially selected from among the combinational indices for the mentioned basin and then the drought classified accordingly. Within the next stage probabilistic approach was determined as based on the site conditions itself based upon, the classification done. The results revealed that the probabilistic approach performed faster in early warnings and so the index was more suitable in indicating the drought occurrence. On the other hand MSUI index revealed a more appropriate performance during the drought period. Finally it is recommended that a joint application of the two indices can be more useful for management and taking of the necessary measures during, and as well, within the initiation span of a drought.