l8 PRESIDENTIAL ADDRESS SECTION A. 



the Rand Water Board barrage was 183,000 cusecs on November 

 23rd, 1917, as compared with 172,000 cusecs in 1894, although the 

 discharge at the Vereeniging Railway Bridge was higher in 1894 

 than it was in 191 7. This is accounted for by a very heavy local 

 fall of rain in 1917 on the 800 square mile catchment between 

 the bridge and the barrage. 



The fall of the river between certain points is given in 

 Table G, and is also shown on the longitudinal section of the 

 Vaal River from Beginderlyn Road Bridge to its junction with 

 the Orange River. (See Plate 4.) 



The largest portion of the catchment area is grazing land, 

 and only a comparatively small area is planted with trees. The 

 chief crops grown on the catchment area are maize, lucerne, 

 barley and wheat, the first-named being by far the largest crop. 

 Cattle do well on the grazing lands, but have in many cases to 

 be removed to good winter farms in the hills for three or four 

 nionths during each year owing to the dearth of good succulent 

 grass on the farms adjoining the river during the dry season. 



Several kinds of fish are found in the Vaal River, the most 

 common being silver, yellow and mud fish and barbel, while 

 carp is common in the Rand reservoirs and trout is found in 

 some of the clear-water tributary streams. 



The catchment area of the Vaal is rich in minerals, gold, 

 diamonds, coal, iron ore, lead and tin being the most common. 

 Salt is also found in several districts, and a good revenue is 

 derived from it. The Transvaal alone supplies nearly 40 per 

 cent, of the world's gold output, and the coal output is over five 

 million tons per annum, and is gradually increasing owing to 

 the expansion of the export trade. 



The geological formations consist of the following: About 

 two-thirds of the Vaal River catchment area is covered by the 

 Ecca Series and Dwyka conglomerate of the Karoo system. This 

 area is chiefly on the Orange Free State side of the river. The 

 remainder of the catchment is covered by the Witwatersrand 

 'Series and Dolomite around Johannesburg, the Pretoria 

 Series, Dolomite and Witwatersrand Series around Vereeniging, 

 the Ventersdorp System around Bloemhof and Warrenton, and 

 the Dwyka Conglomerate in the neighbourhood of Barkly and 

 Kimberley. 



It is a peculiarity of the left bank of the Vaal that there are 

 large tracts of sand, whereas the right bank is fairly free of 

 such deposits. Below Christiana there are considerable areas of 

 calcareous tufa, and the soil is generally very poor in such dis- 

 tricts. 



Afforestation. 



There are ample facilities for tree planting within the Vaal 

 River Catchment Area, and as mining and building timber is. 



