120 (No. 98 ECONOMIC CONDITIONS ing the waters of the White Nile for the benefit of Egypt; a scheme for a Bor -Sobat canal to avoid the waste of water in the sudd region ; works to control the flood waters of the Khor Gash and the Khor Baraka ; and the development of irrigation in the Dongola province.

The Blue Nile irrigation scheme is by far the most important , and has been under consideration in one form or another for nearly twenty years. The under taking has for its object the irrigation of the great Gezira plain by means of a dam to be constructed on the Blue Nile and a main supply canal through the Gezira.

The dam is to be built at Makwa , a few miles south of Sennar, while the canal will take off above the dam and is intended for the irrigationof an initial 300,000 acres . The dam has to pass a discharge of 53,000 cubic ft. per second in a river whose serrated gauge diagram shows that it is subject to great and sudden fluctuations; and, in order to supply the feed canals, a head of water of 52 ft . is required . For the dam to be of sufficient strength to support the strain of such a head it is essential that it should be based upon rock ; the Makwa site , 180 miles from Khartum , fulfilsthis requirement, and is the nearest suitable spot available .

The main canal ( in connection with which a consider able part of the initial digging has been finished ) will lead to a point at which the water will be delivered to about 300,000 acres. One part of this area may lie fallow every year , and one be put under green crops, leaving not less than 100,000 acres for cotton. Since cotton growswell as a winter crop in the Sudan, winter water only is required for its cultivation ; so that it is possible to obtain a sufficient local supply without detriment to the irrigation requirements of Egypt . The revised estimate of the cost of the dam amounts to £E . 1,750,000 ; but , in view of the rise in the price of a