Nahal HaBesor drains a vast area stretching from Sde Boker to southern Mount Hebron, encompassing approximately 3,400 square kilometers—making it Israel’s largest stream system flowing into the Mediterranean. Powerful floods from its tributaries in Mount Hebron create natural springs throughout the western Negev, where small communities have existed since prehistoric times. The largest spring, Ein HaBesor, is now part of the HaBesor National Park.
As Nahal HaBesor crosses the western Negev, it cuts through layers of soft loess—fine particles transported by wind from Sinai and North Africa. Beneath this layer, ancient sands and coastal rock occasionally surface, offering geological evidence of marine incursions over hundreds of thousands of years.