Regional Suspended Load Analysis Using the Watershed Characteristics in the Province of Hormozgan

The present study is aimed at estimating the suspended load discharged from watersheds in the Province of Hormozgan. The mean annual suspended loads were considered as the dependent variable and 21 parameters of morphological and climatic factors were selected as the independent parameters. The data were collected from 19 hydrometry stations for a 21-years period (1991–2011). This analysis is presented in two steps; a principal component analysis (PCA) was further applied to extract the underlying factors (principal component) and use the hierarchical clustering analysis in order to identify homogeneous groups. Multi regression was performed to identify the contribution of each variable. Different clustering scenarios were considered for selecting the optimal number of homogeneity groups, and their overall impacts on cluster validation indices were assessed. These three scenarios include dependent variable, independent parameters and the combined variables. The performance of the models was evaluated using the coefficient of determination (R2) and the Nash-Sutcliffe model efficiency. The watersheds were divided into two clusters and multiple regression models were derived for each homogenous region. Eventually, the models with coefficients of determination of 0.78 and 0.84 were used to estimate the mean annual suspended load. It is recommended to study more watersheds with different condition to reach the plurality and improve the quality of these models for estimation of the suspended load in the ungauged watersheds.