Evaluating the ability of the Al-Dmer and Hella Dams to reduce flood risks in the Al-Dmer Basin A hydro-geometric study
Keywords:
Qalamoun, Ad- Dmer Dam, Floods, RisksAbstract
The Dmer Dam was built to store 2.15 million cubic meters of water and to mitigate flood risks. Its location was chosen at the confluence of several flood-prone valleys. The Dmer watershed is divided into two sub-basins: an eastern one, which collects water from the Gharab, Abu Qais, and Zubeidah mountains; and a western one, which collects water from the Rinkous and Saydnaya mountains. A smaller, earthen dam was also built approximately 2 km south of the town of Hella, with a storage capacity of about 0.5 million cubic meters. However, in 2018, the Dmer Dam reservoir failed to contain the floodwaters, which rose above its northern embankment, causing extensive damage to the cities of Dmer and Adra Industrial City.
The western sub-basin is characterized by higher elevations and gentler slopes than the eastern sub-basin. The SPEI index indicated a predominantly arid climate in areas below 1000 meters above sea level, while positive values indicated a surplus of moisture in the mountainous areas. The western sub-basin had a greater water inflow than the eastern one, suggesting greater water
resource stability. The average runoff volumes and peak flow rates were calculated for both sub-basins, with the western sub-basin having higher values. The amount of water received by the Dmer and Hella dams was estimated, and the results were significantly higher than their storage capacities. Regarding morphometric indicators, the application of morphometric homogeneity equations and stream density calculations did not reveal a significant advantage for either sub-basin, as the values were relatively similar.
The site of the Hella Dam offers better geomorphological conditions than the Dmer Dam, in terms of the height of the rock formations, the inclination of the rock layers, and the depth. While the Dmer Dam site provided a wider area for its reservoir, the weak nature of its sides, composed of alluvial deposits, and the gradual silting up of its bottom due to continuous sedimentation
