Total load transport in gravel bed and sand bed rivers case study: Chelichay watershed

Field experiments were conducted on total load transport in the Chelichay River Basin, a mountainous catchment (1,400 km2) located in north eastern of Iran, to evaluate total load formulas including four gravel bed rivers and a sand bed river (Qaresoo River). Gravel bed rivers in Chelichay River Basin can be grouped into two types; steep slope rivers with high shear values (Chehelchay River and Khormaloo River) and mild slope rivers with low shear values (Narmab River and Soosara River). Two depth integrating suspended load samplers (DH-48 and D-49), and two bed load samplers (Helley-Smith and BLSH) were used to measure total load. The performance is tested of 8 total load transport formulae including 4 macroscopic and 4 microscopic methods. A systematic and thorough analysis of 59 sets of data collected from sand bed river indicate that Yang and Engelund and Hansen reach to the better results, and from four gravel bed rivers confirmed that the methods of Karim and Kennedy and Engelund and Hansen yields the best results for steep slope rivers, and the methods of Einstein and Bijker are ranked highest in gradual slope rivers.