THE AGRICULTURAL JOURNAL. 



489 



Report on Irrigation In Natal, 



By Colonel F. V. Corbett, R.E., Irrigation Expert. 



THE following is a report, dated Gth 

 February, 1901, by Colonel Corbett, 

 on irrigation in Natal : — 



The Colony of Natal has generally an 

 elevation above eea-level of something 

 over 5,000 feet on its N.W. frontier, 

 reckoning from the foot of the Berg. The 

 distance of these uplands from the coast 

 varies from 100 to 125 miles. The average 

 fall from the uplands to the coast is, there- 

 fore, not less than 40 to 50 feet per mile. 

 The rainfall is generally moderate as 

 regards its total amount, but, I understand, 

 frequently very violent for short periods. 

 The natural result has been wholesale 

 erosion and denudation, increased, no 

 doubt, by the absence of forests. Pr. 

 Sutherland, in his pamphlet on the 

 Geology of Natal (1868), alludes to " the 

 great valleys of the Tugela and its tribu- 

 taries, where that river has hollowed out 

 its bed to such a depth that at a distance 

 of 40 miles from the sea the elevation is 

 under 600 feet, although the average 

 elevation of the land on both sides the 

 valley is nearly 4,000 feet." 



2. This very broken conformation of 

 the country, and the general steep slope 

 from which it results, are greatly against 



- the introduction of any general public 

 scheme of irrigation. There are_^ few, if 

 any, large tracts of good arable soil ; the 

 waters rapidly find their way to the sea, 

 and there are no natural basins or lakes, 

 either perfectly or imperfectly formed, in 

 which they can be stored. It is just pos- 

 sible that there may somewhere be a good 

 site for an irrigation reservoir in Natal, 

 but I have not yet succeeded in finding 

 one. Of course, it is impossible to be 

 certain without a survey, and I hope to be 

 able to recommend some site for prelimi- 

 nary survey. But there is no use going to 

 the expense of even a preliminary survey 

 except for a site that commands a sufficient 

 area of suitable soil. 



3. Though there is such a poor prospect 

 for public irrigation schemes, the country 

 seeme, on the whole, fairly well watered 

 in years of normal rainfall, and there are 

 many springs and " spruits," or rivulets, 

 moi-e or less permanent. (I says seems, 

 because my opportunities of personal 



observation have been confined to the 

 very dry years 1899 and 1900. There is 

 good reason to believe that the volume of 

 water available in 1900 was not more than 

 one-third to one-half of the normal.) 

 Many of these sources of irrigation have 

 been taken up, and, as agriculture and 

 railway communication develop no doubt 

 all will be eventually utilised, where no 

 great difficulties intervene. I understand 

 that agriculture, beyond the raising of 

 " mealies," has only quite lately been 

 attempted in Natal ; also, that locusts, 

 rust, and other plagues besides drought, as 

 well as political matters, have greatly 

 retarded its progress. 



Government Canals— Wbenen. 



4. The only " public " canal, made by 

 Government, is at Weenen, where some 

 700 acres of " thorns " land are com- 

 manded by a channel taken out from the 

 Bushman's Kiver. A trial line has lately 

 been laid down on the ground for a second 

 canal on a higher level, to command nearly 

 2,000 acres, and as there is plenty of water 

 for both, this channel should be con- 

 structed as soon as possible, if the estimate 

 shows that it can be done at a cost that 

 can be recouped by the lease or sale of the 

 lands put under irrigation. There is some 

 awkward cross drainage to provide for, and 

 the works for this purpose should be of a 

 substantial and permanent nature, other- 

 wise the cost of maintenance may be very 

 high. At present the existing canal gets 

 too liberal a supply of water, and the 

 lower parts of the land under it are in- 

 clined to get water-logged ; some signs of 

 alkali have appeared on the surface. This 

 matter should be looked to and a drain 

 cut if necessary. If there is any delay in 

 the construction of the new furrow, some 

 limit should be put on the volume to be 

 carried in the existing one, which should 

 eventually be re-modelled to carry a 

 smaller volume. 



5. This (Weenen) is the most favourable 

 combination of climate, water, and soil 

 that I have met with in the country, and 

 the difficulties of finance are removed by 

 the fact that the land belongs (or belonged, 

 in the case, of the running canal ; to the 



