Wadi Najran[1] (Arabic: وَادِي نَجْرَان|[[Wadi|Wādī]] Najrān) is one of the largest valleys in the Arabian Peninsula, and its tributaries come from the Sarat mountains and hills surrounding the area. It extends 180mile to the east from its mouth in the plains where it ends in the sands of the Empty Quarter. The average size in the plains is 1000m (3,000feet).
The river divides the city of Najran into two parts, causing extensive damage when it floods. It is the main source of water supply for the region and brings large amounts of silt deposited in the plains and flooded farms along its banks Wiczidha fertility. The Najran Valley Dam is located on its course.[2] [3]