Geodiversity

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Geology


The Barouk Mountain comprises rocks from the third geological era (Pliocene) which has undergone major tectonic movement that divided Mount Lebanon into 2 parallel parts; the eastern range is called the Anti-Lebanon, and the western range is called Mount Lebanon. The two mountain ranges are separated by the Beqaa Valley, which is composed of recent infill sediments. The main rocks are limestone. The whole of the Barouk Mountain is cavernous limestone, with many surface features such as dolines indicating the underlying cavernous
form of the mountain range. One particularly noteworthy cave, estimated to be 700 meters long, is located near Niha village. Villagers report an abundance of stalactites and stalagmites and that there is an underground body of water.



Geomorphology


Further south from Dahr El Baidar is the highest peak on the range at 1980 meters. The trend from north to south is for the eastern slopes to change from very steep to less steep and for the western slopes to become increasingly steep. The top of the Barouk range becomes increasingly narrow towards the south.

 




Hydrology


Precipitation in the watershed is the source of both surface streamflow and groundwater. The major portion of this occurs as rain. Snowfall often occurs at the upper elevations but snow seldom persists more than a few days and disappears before the end of the rainy season.
Normally snow has little overall direct effect on stream-flow within the watershed. However, on rare occasions warm rains falling on the snow-pack may result in rapid melting and release of large quantities of water at a time when the soils are already fully saturated. These conditions result in rapid runoff and floods.
A large proportion of the exposed surface rock in the Barouk region is cavernous, fissured and broken limestone, and its porous condition makes it very permeable. This results in much of the precipitation infiltrating with minimum surface runoff despite the often-shallow soils and sparse vegetative cover. Water percolates downward through the various formations and feeds the many large springs found on lower slopes in the area. Such springs help maintain stream-flow during the April to November dry season.
Surface water flows originating on the range are mostly seasonal but some are perennial.

Underground water generates outflow rivers such as:
- Al Awali River, more commonly known as Al-Barouk river
- Damour River, known as Al-Safa river
The summit of the range is considered as a divide between two hydrological systems because of the difference between the two slopes of the mountain. The eastern slope is much steeper and favors surface stream flows, whereas the western slope is less steep and favors ground water aquifers.
The rivers that flow in the valleys are the major source of agriculture irrigation and supply a dozen Shouf villages with domestic water and some of the western Bekaa villages. It is also the main source of water for the Aammiq Swamp in the Bekaa.


Pedology

Physical characteristics of the soils are:
1- Homogenous, belonging to the red brown Mediterranean soils formed on hard marl limestone.
2-derived from Jurassic, Balthonian, Callovian to Oxfordien - Portlandian marl limestone
3-Stone contents ranges from 80 - 90 %

From an erosion point of view these soils are in a state of equilibrium due to:
1-High permeability
2-Mask of calcareous fragments
3-Good vegetative cover
4-Good drainage

Climatology

The annual rainfall average is 1200 mm, and the mean annual temperature is 11.3° C. The mean daily maximum temperature is 23.4° C in August whereas the mean minimum temperature in January is -0.6° C. The absolute temperature ranges from -10.8° C in January to 32.3° C in August. The mean relative humidity lies around 65% but the eastern slopes are slightly dryer. There are about 50 to 55 days of snow fall per year (Service Meteo/ Ministry of Public Work and Transport).