Blue Nile. 21

CHAPTER II.

TRIBUTARIES OF THE WHITE NILE.

(a) Blue Nile. (e) Tributaries of Bahr el

(6) Sobat. Ghazal.

(c) Bahr ez Zerap. (/) Southern Affluents of

(d) Bahr el Ghazal. the Buhur el Ghazal. and el Arab.

(a) The Blue Nile.

General Description.

The Blue Nile (or Bahr el Azrek) has its sources in the mountains of Abyssinia, i.e., in the third great reservoir of the Nile, Lake Tsana. This lake has an area of 1,160 square miles and is 5,800 feet above sea level.

The river is 846 miles long. It is comparatively clear in summer, but during flood, from the beginning of June to the end of October, it is of a reddish-brown colour, highly charged with alluvium.

The Blue Nile flood swells fitfully in May, begins to rise

steadily in June, and is at its maximum about the 25th August. It falls rapidly after the middle of

September.

During the dry season the Blue Nile is so reduced that there is sometimes not sufficient water for the small vessels engaged in transporting produce from Sennar

to Omdurman. In this season the water is beautifully

clear, y> hence the name of the Bahr el Azrek. It is much

superior in quality to the White Nile water.