Detect the Water Flow Characteristic of the Tigris River by Using HFC-RAS Program

Abstract The Tigris River has recently suffered from a significant decrease in water levels, in addition to the scarcity of drainage and the velocity of water entering the river from Syria, Turkey and Iran. These decreases in the levels leads gradually to drying of some parts of the banks, raising the level of the riverbed, and the appearance of dry areas in the middle of the river. This led to a decrease in the width of the river and hindering the movement of river navigation. Also, the decrease in water levels leads to an impact on the water levels needed by the liquefaction plants to secure the drinking water needed by the city of Baghdad. So, it is necessary to find a technique in which the flow characteristics of the Tigris River are revealed in periods of scarcity, in order to create planning solutions that increase the water height to levels that ensure uninterrupted water supply in the liquefaction plants all over the river. Therefore, this research aims to simulate the movement of water in the Tigris River to detect flow characteristics in times of scarcity by building a one-dimensional hydraulic model (for steady flow) using the HEC-RAS program. Where the simulation will be done based on the geometric data for the shape of the river, as well as the initial and boundary conditions that represent the levels and drainages of water for the river at periods of scarcity, in addition to identifying the values of the Manning coefficient. The model will produce results that are longitudinal and cross sections, flow charts, tables and values, on the basis of which planning solutions are proposed to raise the water level to the required level, restore the natural properties of flow, and examine the compatibility of the proposed solution with the reality of the situation. It was concluded that raising the water level would be by proposing an (Ungated Inline wirs) dam. The proposed dam was tested at a minimum level in times of scarcity, ensuring its ability to raise water levels to the height required for all liquefaction plants installed along the river that required a minimum level of 28.5 m.