The scenery along its banks is tame compared with that of the more northern rivers.
The Nahr-el-Auly or Bostrenus rises from a source to the north-east of Barouk, and flows in a nearly straight course to the south-west for a distance of nearly thirty-five miles, when it is joined by a stream from Jezzin, which flows into it from the south-east.

On receiving this stream, the Auly turns almost at a right angle, and flows to the west down the fine alluvial track called Merj Bisry, passing from this point through comparatively low ground, and between swelling hills, until it reaches the sea two miles to the north of Sidon.

Its entire course is not less than sixty miles.
The Zaherany repeats on a smaller scale the course of the Bostrenus.

It rises near Jerju'a from the western flank of Jebel Rihan, the southern extremity of the Lebanon range, and flows at first to the south-west.
The source is "a fine large fountain bursting forth with violence, and with water enough for a mill race."[157] From this the river flows in a deep valley, brawling and foaming along its course, through tracts of green grass shaded by black walnut-trees for a distance of about five miles, after which, just opposite Jerju'a, it breaks through one of the spurs from Rihan by a magnificent chasm.

The gorge is one "than which there are few deeper or more savage in Lebanon.