Thumamah (King Khalid Royal Reserve)

Thumamah Park is a unique natural ecosystem and popular entertainment center due to its scenic surroundings and proximity to the Ar Riyadh City. It is about 100 km from the central Ar Riyadh, covering an area of approximately 170 sq. km. The study area is located between 25⁰ 140 02.5300 N, 46⁰  370 12.1500 E and 25⁰ 180 14.3300 N 46⁰  410 27.5100 E. The Park is a large and shallow depression, which receives runoff water several times the amount of the actual rainfall. It is flanked by Aramah escarpment and adjoining wadis. Aramah escarpment, which is capped with upper Cretaceous limestone, extends, 250 km northeast of Arriyadh with maximum elevation of 805 m a.s.l. and 120 m above the nearby sandy plains. The Thumamah Park is divided into different zones, each with a specific purpose, from limited camping area to ‘high energy activity areas’. A large portion of the study area is also left unattended which is now regarded as a protective desert zone and currently serving as a land bank for future recreation use. Geomorphologically its landscape, is identified into three fundamental components: lower plain (lowland), escarpment and upland plateau. The average highest point on the site is 805 m a.s.l and the average lowest point is 560 m a.s.l giving altitudinal range of 245 m. The lowland is composed of flatlands including: depressions of various areas, crossing wadis and run off channels, sandy and gravel plains. The escarpment is the dominant component of the site and characterized by both sloping and vertical cliffs interrupted by well developed wadi system, sand and gravel areas, and small mosaic depressions (Brown 1960). The upland plateau is mostly bare gravel land interrupted by small depressions ‘‘grooves’’ which support few plant growths (Fig. 1). The rainfall in the area is highly variable. The mean annual precipitation is 20 mm; of which 80 % is received from December through April and the prevailing winds from north. The mean minimum and maximum annual temperature is 15⁰ and 37⁰C. The maximum temperature often reaches 47⁰C during July–August, while the lowest minimum temperature touches below 3⁰C in some extreme cold days during winter. (Courtesy: El-Sheikh, M.A.; Thomas, J. et al. 2013. Vegetation of Thumamah Nature Park: a managed arid land site  in Saudi Arabia. Rend. Fis. Acc. Lincei, 24:349–367