Assessment of the Riverbank Stability for Tigris River in Salahaddin Governorate/Iraq Using BSTEM Model

The riverbanks are a critical component of river ecosystems that provide various ecological, social, and economic benefits. Effective riverbank management is essential for maintaining its functions while minimizing the risks associated with instability. The fluctuation of water levels in the river negatively affects riverbank stability; therefore, the present study aims to examine the instability of the riverbank caused by the variations in water flow within the Tigris River as the basis of analysis. The flow variation effects during (2022) in Salah Al-Din Governorate, which began from the Makhoul dam site (upstream) to the end of Tikrit City (downstream), were investigated by computing a series of safety factors related to outflow events for (20) cross sections along the (82) km reach of Tigris River. The BSTEM algorithm integrated into the HEC-RAS model package was utilized. The results showed that the rate of change in flow at each cross-section impacts the calculated safety factor. Also, the results showed that all cross-sections were stable, and some were conditional stable, meaning that the riverbank is not entirely stable, however, still holding up under the existing conditions. However, caution should be exercised, and it may require monitoring and evaluation to prevent future instability issues.