The real Sudd region lies between Ghaba Shambe and Lake No, on a length of 380 kilometres. Between Fort Berkeley and Gondokoro, the flood as well as the summer supplies are within banks. Between Gondokoro and Bor, the summer supply is well within banks, but the floods overflow the valley. Between Bor and Ghaba Shambe the summer supply is just within banks, but the floods overflow freely. Between Ghaba Shambe and Lake No the summer supply overflows the banks, and hence there result the periodical barrings or sudds of the Nile by the floating vegetation so common in this region. While the summer supply is within banks it can insure a clear waterway; but when not only the floods but the summer supplies ordinarily overflow the banks, the stream must be aided artificially if it is to keep its waterway clear. The ordinary width of the river south of Hillet-el-Nuer is between 50 and 60 metres, but in the reach of the old sudd blocks numbers 16 to 19 it diminishes in places to 25 metres, and in the reach blocked by sudd block number 15 increases to 200. North of Hillet-el-Nuer, the width varies from 60 to 150 metres, but the mean width may be taken as from 75 to 80 metres. The velocity is about 75 centimetres per second, which is a good velocity for clear water; and Sir William Garstin remarks at one place that since the sudds were cleared the channel of the Albert Nile seems to be deepening and widening itself, and he states in another place that the extent of overflow over the mayahs or side depressions is decreasing. With proper training works and dredging it should be possible to reduce the length of the main channel of the Albert Nile between Gondokoro and Bor from 175 kilometres to 160; between Bor and Ghaba Shambe from 206 kilometres to 145; and between Ghaba Shambe and Lake No from 380 kilometres to 305. Or the length of channel from Gondokoro to Lake No might be reduced from 761 kilometres to 610. Some of the curves are nearly complete circles, needing but little work to cut off extensive lengths. Between Ghaba Shambe and Lake No there were 19 sudd blocks of which all but one were removed by Major Peake, R. A., and Lieut. Drury, R. N., in 1900 and 1901. Their positions are indicated on Plate VI. South of Hillet-el-Nuer is sudd block No. 15, the only one remaining to be removed. Owing to this block, the Albert Nile leaves its true channel, which is from 5 to 6 metres deep, and, on a length of 43 kilometres, follows a series of mayahs, pools and marshes with a depth of from 1¹⁄₄ to 2 metres. The original channel was closed by a boat laden with ivory sinking in the true channel during the Dervish domination. The boat has been found, the ivory recovered and the work of sudd clearing commenced, but the work has not yet been completed.