Hydro-Geomorphic Hazard Assessment in the Towns of Mnin and Halboun From the Halboun Valley Basin

Abstract

The town of Halboun faces flood problems in its entire urban area, as it is located in a triangular depression, its base is part of the Halboun Valley, and its head is at the height of the Karm Salim Valley, between the Qalaa Mountains to the north, and Al-Zahri Mountains to the south. Its main roads slope from east to west at varying angles, ranging between (10-25) degrees, while its agricultural lands are affected by the water flowing from a point located north of Ain Al-Fakhukh, after it collects from the valleys of Al-Shaab - Beisan, and Al-Dishar, in a location where the width of the channel does not exceed (5) meters, and its depth is two meters, and its annual quantities were estimated at about (3.5) mm3, the highest of which was in January, where the volume of surface runoff ranged between (0.57-0.59) mm3, with flow speeds between (1.65-42.4) km/h. As for the town of Mnin, it is located in a rectangular, wide depression, with a gentle slope of the surface, so it is not

affected by flood waters, except for the neighborhoods of its northern section, which are built at the foot of the Ain and Martaqla mountains, whose slopes ranged between (10-30) degrees, and are affected by the flood waters collected from the two basins located east and west of the Ain mountain, and their annual quantities were estimated at about (1.7) m. m3, the highest of which was in January, where it ranged between (0.29-0.3) m. m3, with flow speeds between (1.65-1.8) km/h. The basins of the town of Halboun are more dangerous than their counterparts in the town of Mnin, due to the combination of many factors: they are larger in area, steeper, more flat, less elongated, and have denser waterway networks in terms of numbers and lengths, which means that their two waterway networks are more efficient in transporting water and loads towards the main valley through the town. The town is also located directly opposite the running water, with its urban mass and agricultural lands extending along a narrow strip of the bottom of the gorge valley.  As for the town of Mnin, the flood waters of its eastern and western neighborhoods flow through the Ain-Saydnaya road, and the western road, respectively, and end in its parks and valley, with the availability of more effective protection measures than in the town of Halboun, such as the subsurface canal, and sewage networks.