31 



The conservation of forest and bush in the drainage area of reservoirs is thus of 

 great importance ; this point should not be overlooked in connection with the water 

 supply of Maritzburg and Durban. 



UTILISATION OF WATER. IRRIGATION. The regularity of the water supply of a 

 country is very desirable, for the value of each stream depends upon its normal, not 

 its total, delivery, whether the water be applied for irrigation, or as a source of power 

 or for mining or industrial purposes. Forests, by their great regulating effect on the water 

 supply, may thus often render irrigation possible, and serve better for the purpose than 

 costly dams. The difficulties that beset irrigation in this country are precisely those that 

 are removed by using a forest-regulated water supply. " Irrigator," writing recently in 

 the Natal Witness, states that they are the following : " 1. That the rivers are not to be 

 depended upon to yield a supply of water during the winter months sufficient for irrigating 

 large acreages. 2. The making of dams across them to enable the water to be led out of 

 them would, except in exceptional places, be a very expensive undertaking, with a great 

 probability of their being swept away when the great rushes of water occur during 

 the summer months. 3. The watercourses taken out from the streams would, for the 

 most part, have to traverse the sides of more or less hills, and these would be entirely 

 filled up by the washings brought down from the slopes during the heavy summer 

 rains." The dams themselves would also become filled with washings. At the Cape, the 

 large Beaufort West reservoir, constructed in 1880, with a capacity of 572 million 

 gallons, for irrigation purposes, is said to be silting up so rapidly as to become useless 

 in a limited number of years. 



Now that the influence of forests on the flow of water has boen explained, it will be 

 patent that their destruction would increase all these difficulties and that their extension 

 would have a contrary effect. 



The subject of irrigation is of great and growing interest not only in Natal, but 

 throughout South Africa. In countries placed in similar conditions of climate, such as 

 India, or Italy and most other Mediterranean countries, irrigation is looked upon as a 

 necessity ; agriculture has become almost entirely dependent on its use, and the works 

 for the purpose have reached an immense development. 



The conclusion of a paper read by Mr. B. E. Fernow of the U. S. Department of 

 Agriculture, at the 1889 meeting of the American Association, applies with much force to 

 some parts of South Africa : " A rational management of the water capital of the world 

 in connection with the agricultural use of the soil will become the economic problem of 

 the highest importance, as the necessity for increased food production calls for intensive 



methods While with one hand we pay exorbitant prices in land and wasted 



energy to got the plains reforested, and that with poor success, with the other hand we 

 ffer a premium for forest destruction in mountains by leaving them without proper 



