— 30 — 
Sir William Garstin, the waters of Lake Albert are brackish near the 
shores, but perfectly sweet and clear in the middle of the lake. It is 
due to the waters of Lake Victoria that those of Lake Albert are sweet. 
The catchment basin of the Albert Nile at its head where it leaves Lake 
Albert is about 379,000 square kilometres of which 244,000 square 
kilometres discharge into Lake Victoria. The rainfall over the addi- 
tional 135,000 square kilometres may be considered as 1250 millimetres 
per annum, with seasons similar to those on Lake Victoria. The 
evaporation from Lake Albert must be greater than that from Lake 
Victoria, but if we exclude the joint areas of Lakes Victoria, Albert, 
Edward and Choga, and taking them as 70,000 square kilometres, 
consider that their rainfall is equalized by their evaporation, there 
remains from the 379,000 square kilometres of catchment basin about 
309,000 square kilometres. An annual rainfall of 1250 millimetres 
means for 309,000 square kilometres a total rainfall of 380 cubic 
kilometres. The discharges of Lake Albert may be taken as varying 
from 500 cubic metres per second to 1100, with a mean of 800 cubic 
metres per second.. This latter figure represents in one year 26 cubic 
kilometres or ygth the annual rainfall. We may compare with this 
the mean discharge of Lake Victoria of about 580 cubic metres per 
second and y^th of the annual rainfall of its catchment basin excluding 
the lake area. 
A reference to Plate V will show how great is the regulating effect 
of Lake Albert on the Nile. Owing to the fact that an increase in the 
discharge of the Victoria Nile cannot pass down the Albert Nile before 
the whole area of Lake Albert has risen, the floods of the Victoria 
Nile are delayed nearly 5 months in their passage down the Albert Nile ; 
a rise of 1 metre on Lake Albert meaning an increased cube of 
4,500,000,000 cubic metres. If this takes place in one year, it represents 
an increased discharge of 150 cubic metres per second irrespective of 
what passes down the channel of Lake Albert. 
If it were considered necessary to insure 1200 cubic metres per 
second as the discharge of the Albert Nile from the 15th January to 
the 15th May, it would mean adding 400 cubic metres per second to 
the mean discharge for 4 months, and deducting 200 cubic metres per 
second from the mean discharge for the remaining 8 months. By 
storing the surplus waters of good years by means of a weir capable 
of holding up 3 or 4 metres of water at the outlet of the lake, it 
would be possible to insure this discharge every year during the four 
