Hydrodynamic Model-Based Evaluation of Sediment Transport Capacity for the Makhool-Samarra Reach of Tigris River

Abstract

 Flow velocities within most of the M akhool-Samaraa Reach of the Tigris River are considered high compared to the local and worldwide flow velocity ranges.  Toffaleti sediment transport function with the Van Rijn fall velocity and the effective depthto-width computation methods are the most compatible and suitable methods for computing the Sediment Transport Potential (STP) in the M akhool-Samaraa Reach of the Tigris River.  The computed STPs in the M akhool-Samaraa Reach of the Tigris River are considered high on local and global scales, especially during high flow.  M edium gravel is the larger grain gradation class that can be transported. However, the suspended sediment is the dominant part of the Sediment Transport Capacity (STC), with a great majority of clay and very fine silt. This paper implemented an HEC-RAS-based steady two-dimensional hydrodynamic model to evaluate the hydraulic characteristics and Sediment Transport Capacity (STC) of the M akhool-Samarra Reach of the Tigris River, where this part is not already investigated. This model was prepared with the aid of topographical surveys, hydraulic measurements, and laboratory tests, as well as recorded data. The main findings show that the flow velocities within most of the studied reach are considered high compared to the local and worldwide flow velocity ranges in natural rivers. Also, the Toffaleti sediment transport function with the Van Rijn fall velocity and the effective depth-to-width computation methods are the most compatible and suitable methods for computing the Sediment Transport Potential (STP) in the studied reach.With the maximum flow, the computed STP was less than the average (5.7×10 6 tons/day) in 45% of the reach length, where the maximum STP is 8.7×10 6 tons/day. However, with the minimum flow, the STP intermittently fluctuates below the average (0.2×10 6 tons/day) in 48% of the reach length, where the minimum STP is 0.14×10 6 tons/day. Generally, these STPs are little more than the Tigris River in M osul and much higher than that in Baghdad. Also, these STPs are considered high on a global scale, especially during high flow. M edium gravel is the larger grain gradation class that can be transported. It constitutes less than 0.00005 % of the STP. Furthermore, the STC computations clearly show that the suspended sediment is the dominant part of the STC and the bed material constitutes less than 0.002% of the STC of the total load. However, most of the STC concerns the clay and very fine silt.

Assessing the influence of climate change on sediment dynamics in the proposed makhool dam reservoir, Iraq

“…The pebbles are composed chiefly of silicates and carbonates, with a lesser presence of igneous and metamorphic rocks [17]. The predominant constituent of bed material in the Tigris River within Mosul and Tikrit is medium gravel [15]. The concentration of suspended sediment at the location of the proposed Makhool Dam is shown in Table 1.…”

“…Moreover, the HEC-RAS software was used by Mohammad et al [3] to implement hydrodynamic and sediment transport dynamic models to investigate the flow and sediment transport aspects in the Tigris River and Mosul Dam reservoir in Iraq. Namaa et al [15] used the same software to determine the hydraulic characteristics and sediment transport capacity of the Makhool-Samarra Reach of the Tigris River, Iraq.…”

Impact of Dam Materials and Hydraulic Properties on Developing the Breaching Dimensions

“…One of the dynamic models created by the U.S. Army Corps of Engineers is the HEC-RAS software. Steady, semiunsteady, and unsteady flows with one-and two-dimensional flow are possible to simulate in this model [14]. Three processes are involved in the dam breach modeling by using HEC-RAS software: (1) directing the inflow across the basin, (2) assessing the features of the dam breah, and (3) routing the flood wave downstream.…”

Simulation of Bed Change in Al-Musayyab Canal using HEC-RAS Software

“…Nama et al, 2022). Moreover, the maximum load of sediment transport can be represented as the capacity of sediment discharge in streams(Nama et al, 2022).…”

“…Nama et al, 2022). Moreover, the maximum load of sediment transport can be represented as the capacity of sediment discharge in streams(Nama et al, 2022). Important studies have utilized field and laboratory-based methods to predict the potential capacity of sediment transport in naturalstreams, (Aziz and Prasad, 1985; Finkner et al, 1989; Celik and Rodi, 1991; Yang and Wan, 1991; Chanson, 1999; Merten et al, 2001; Yang, 2005; Ali et al, 2012; McPherson, 2020; Zhang et al, 2021).…”