spatial variation of bedload shape characteristic towards downstream )case study: ghalesar watershed, sari(

investigating downstream changes in bed load shape can be useful to detect watershedhydrological processes and it is very important to design hydraulic structures and to managecapacity of large storage dams, properly. regarding to doing of enforcement studies, thisresearch was conducted in qalesar river in upstream of chahardangeh watershed in mazandaranprovince. after recognition of the study area, 6 sections were selected towards downstreamfor bed load sampling. laboratory analysis were done to measure and calculate some bedload shape characteristics including skewness, kurtosis, mean, mode, percent of sand, finegravel, silt and clay, sediment texture, small, medium and large diameters, nominal diameter,sphericity, rounding, width ratio, shape factor and d10, d50 and d90. results indicated adecreasing trend in shape factor and sphericity, an increasing trend in mean diameters androundness, a complex trend in width ratio and a uniform trend in 3 axes. our finding alsoindicated that this variations may be affected by physiographic, lithologic and geotechnicalcharacteristics of the study area.