تعيين منحني سنجه رسوب در رودخانه هاي مركب با روش مقاطع پوش

Sediment Rating Curve in Compound River Channels Using the Envelope Sections Method

Part of flow spills over bank(s) and flows on flood plain(s) in many natural river flood events. This affects flow behavior and generates a complex interaction mechanism between flows in main channel and flood plains. More than two decades, various researchers associated with problems in rivers and flood flows attempt to understand different aspects of this phenomenon. Although many features of hydraulics in compound river channels still remain questionable, however, it has been developed considerably compared to sediment transport features. So far, almost all studies in hydraulics of sediment flood flows in compound open channels are performed in laboratories, controlled conditions. Therefore it is necessary investigate this type of flow in natural rivers. The sediment rating curves in compound natural rivers with varying cross sectional geometry has been investigated in this paper using the already developed envelope sections method (ESM) combined with the sediment transport formulation of Ackers and White. Due to relatively sufficient data available, the compound cross section of Minab River at Brenttin hydrometric station is selected as case study. The results of applying the developed method show that the measured sediment data are with in the limits of sediment rating curves for the upper and lower cross sections. This method may therefore be recommended to generate sediment rating curves in rivers with highly varied geometrical cross sections.