86 



and the other fresli and useful for all purposes. I notice that 

 in the bore put down at Port Wakefield by the Eugiireer-in- 

 Chief to a depth of 550 feet, described in the Society's Pro- 

 ceediugs in 1881, the water, found at depths varying from 

 about -40 feet to 230 feet from the surface, was very salt, and 

 the bore was abandoned, as there was no sign that the expen- 

 diture would result in a supply of water suitable for locomotive 

 engines or any other purpose. I think it would be worth 

 inquiring as to whether this bore was not in the line of this- 

 stream of underground salt water just referred to, and, by 

 taking the lines of fresli water wells across the plain from 

 near Balaklava westwards, endeavour to ascertain, if possible, 

 the localitv of this underground fresh water near Port A\^ake- 

 field. 



(2). The source of these imderground waters is percolation 

 from the surface. This percolation takes place chiefly under 

 the beds of rivers, creeks, and other water-courses m the hills- 

 and on the plains, in a vertical direction, and also laterally on 

 each side of the river. 



In South Australia that portion of the rainfall is much the 

 larger which never reaches our rivers and creeks, but enters 

 the ground on or near the spot where it falls, and goes to 

 swell the volume of the subterranean streams. This proportion 

 of the rainfall thus sinking into the ground varies very much 

 in different countries and from various causes. 



This subject of the proportion of our rainfall lost by percola- 

 tion and other causes is a very difficult one, and also of the 

 greatest practical importance. In taking gaugings of the 

 water flowing in the Eiver Wakefield during a part of the year 

 1886, I found that out of an average rainfall over tbe catch- 

 ment area of that river of 2 If inches, the quantity flowing in the 

 river would only amount to y\fy of an inch per annum. As the 

 gaugings were only taken for three months, the quantity per 

 annum is only approximately estimated. I find that the gaug- 

 ings of the Para Eiver at Barossa in 188-4 show about five inches 

 discharged in the river out of an annual rainfall of 2H inches, 

 and at Beetaloo in 1885 only y% inch out of a rainfall of 25-^ 

 inches. These data show an enormous loss by percolation and 

 evaporation and absorption, especially in the years 1885 and 

 1S8G. The loss from these causes is about as follows, viz. : — 

 At Barossa, in 1884, 16^ inches loss out of a total rainfall of 

 2H inches ; at Beetaloo, in 1885, 24yV inches loss out of a total 

 rainfall oE 25-^^ inches, and at the Eiver Wakefield, in 1886-, 

 21| inches out of a total of 2 If inches annual rainfall. Assum- 

 ing the loss by evaporation and absorption to be half the above 

 total quantities lost from all causes, the annual loss due alone 

 to percolation underground will be as follows, viz. : — At the 



