Recognition of channel pattern of Khar-Rud River (south of Qazvin Province) based on morphological and sedimentological parameters

The Khar-Rud river drainage basin (area=5500 Km2) is located in south of Qazvin Province. The maximum and minimum basin elevations are 1680 to 1200 m (above sea level) respectively; it occurs in the Central Iran structural zone. In this study, the style of river was determined based on morphological and sedimentological parameters. The quantitative morphological parameters include: sinuosity, width/depth ratio, entrenchment ratio of the bed, channel slope, the central angle of the meander and braiding ratio. In addition, some descriptive parameters such as the meander type were also discussed. In the western part of the study area (before entrance of Shurabeh tributary), this river is of F and B types (both single channel; sinuosity>1.5) mainly with a sandy bed (dominant facies: Sh, St and Sr). In the central part, the channel pattern changes to type D (Av. braiding index=3.73; gravelly bed; dominant facies: Gms and Gm). In the eastern part, this river is single channel (type C, dominant facies Gms, St and Sh). Textural parameters of single channel types (F, B and C) are similar, different from that of multi channel type (D).