Analysis of stream flow conditions using hydrologic environmental drought index

According to diversity and complexity of hydrological processes, more information and data for analysis of this aspect of drought, is needed. Hence, to achieve an index using observed data, simplicity and robustness, which is also capable analysis of this kind of drought, can be valuable. In this research, an index that includes both environmental and hydrological drought aspects was introduced. The foundation of the proposed method using flow duration curve as a method of analysis of hydrological drought and low flows is proposed. Performance of the desired Index (FDCI), with a proposed new Streamflow drought index (SDI) has been compared. To implement the method, three areas (Chalus, Joestan and Frizi river) with different aspects of size, climates and length of records, which are located in various regions of Iran, were selected. The results showed that the correlation between the proposed index and SDI (R2= 0.98, S.E=0.02) is highly significant. The superiority of the proposed method is the use of all available historical data without changing the original data. Hence, the application of FDCI for the analysis of hydrological droughts in rivers located in the Mediterranean and semi-arid regions should be consider as a main result of this research.