WATER CONSERVATION, IRRIGATION AND DRAINAGE IN N.S.W. 223 



PROJECTS for WATER CONSERVATION, IRRIGATION 

 and DRAINAGE in NEW SOUTH WALES. 



By H. G. McKlNNEY, M.E., M. Inst. C.E. 



[Read before the Royal Society of N. 8. Wales, December 4, 1901.~] 



Physical conditions necessary for extensive irrigation. — As a 

 rule, when we find mountains of sufficient height to constitute 

 the source of large permanent rivers, and when these rivers flow 

 for a considerable part of their course through alluvial plains, we 

 may conclude that the conditions favour irrigation on an extensive 

 scale. Broadly speaking these are the conditions which have 

 been made so much of in Upper India and in Egypt, as also the 

 conditions under which extensive areas have been brought into 

 cultivation in the Western States of America, and under which 

 Lombardy has long been the garden of Europe. They are the 

 conditions too under which in a more or less rough and unscientific 

 manner great results have been accomplished in China, and to 

 which we may look for great developments in the plains of South 

 America, 



Best conditions obtainable. — These conditions naturally vary 

 greatly indifferent countries and in different parts of the same 

 country. When perpetual snows on the higher parts of the catch- 

 ment area of a river maintain a high supply of water during the 

 spring and summer, when the supply is maintained up to the 

 required standard by rainfall in winter, and when the water 

 carries with it a fertilising deposit, these conditions combined may 

 be considered the most advantageous which can be looked for. 

 The actual conditions existing in Egypt are probably the closest 

 approach on a large scale to this ideal. Among the great rivers 

 of the world whose waters are being used or can be used exten- 

 sively for irrigation, the Nile on two important points stands 

 pre-eminent. Lakes Victoria and Albert together with the 



