Determination of Hydrological Homogenous Regions in the West of Hamoun-Jazmourian River Basin

Extensive available hydrological characteristics (precipitation, temperature, streamflow data and physiographic attributes of catchments) can be used to extract hydrological similar catchments. In this research cluster analysis as a new and effective method, was used for grouping catchments into several groups or clusters. In order to understanding the hydrologic similarity, 28 characteristics (descriptors) of location, physiographic, climatic and land use of 15 catchments with heterogeneous characteristics located in the western part of the Hamoun-Jazmourian river basin were used. Selecting of characteristics were done based on the hydrological response specification which provided insight into the hydrologic performance of the catchments. In RStudio software, using PCA algorithm, the components and main characteristics were extracted, then the number of optimum clusters with the Davies-Bouldin criterion was determined and the clustering of the catchments into homogenous classes was performed using k-means algorithm. The results showed that the latitude of gravity center, area, length of main river, height of hydrometric gauge, slope and percentage of poor rangelands are as the main attributes from 28 attributes, also, the Davies-Bouldin criterion was 2.46 for the number of clusters equal to 3, which indicates the number of clusters in the k-means algorithm. After clustering the catchments, it was determined that most of the catchments in the same clusters are located in the vicinity of each other. The results of this study enable us to interpret the hydrologic behavior in the study area for purposes such as streamflow regionalization in ungauged catchments of this region and regional flood frequency analysis.