Variability of Amount and Particle Size Distribution and Morphometric Characteristics of Bed Loads Due to Sand and Gravel Mining

Awareness of the variety، quality and quantity of sediment transport rates in different time scales، is inevitable for monitoring the hydraulic behavior of channel and flow affected by the mining activities and proper management of sand removal. However، less comprehensive studies have been conducted on fluvial behavior and characteristics of the bed load under different conditions. The present study therefore aimed to investigate the effect of sand mining with different harvesting and hydrological conditions on particle size distribution and morphometric characteristics of bed sediments for three sand and gravel mines viz. Vaze-e-Olia، Vaze-e-Sofla and Alesh-Roud in Mazandaran Province، Iran. In order to achieve the study purposes، different bed sediments characteristics were computed by GRADISTAT and GIAS softwares after extracting bed sediments morphometric specifications with the help of Gravelometer and Paint software for sampling sites located in the upstream and the downstream of the study mines. The samplings were taken place on monthly basis during a year from February 2012 to January 2013. The results of the study showed that the different natural and sand and gravel mining conditions and other anthropogenic activities affected the particle size distribution and morphometric characteristics of riverbed sediments. According to the statistical analyses، most of the variables were non-significantly (P>0. 07) differed in the upstream and the downstream sites in the study mines.