26 Proceedmgs of the Rorjal Society of Victoria. 



see that sufficient waterway can be provided for tlie surplus 

 water. 



After dealing with many other important considerations, 

 Mr. Jennings said, with regard to the materials for 

 construction, it will generally be found that if earth is 

 obtainable wliich is not of too porous a nature, the cost will 

 be less than stone, even if this is available on the spot. The 

 supply of water during construction must also be taken into 

 consideration, as the most satisfactory way of constructing 

 an earthen dam is to water it and roll it in. layers of about 

 6 inches thick, this forms a stronger and more impervious 

 dam than one with only a puddle wall in the centre. It is 

 desirable, if possible, to face the side slope next the water 

 with stone, and consequently it will have to be noted how 

 near the site this can be procured. fStone or brick will be 

 required for the head works, and in most cases for the weir, 

 and the facilities for procuring brick earth must also be 

 investigated, as well as the question of fuel for making 

 bricks. Sometimes a site, which to an unexperienced eye 

 appears most umpromising, turns out particularly desirable ; 

 for instance, it may be possible to consti'uct a tunnel which 

 will bring land under command which at first seems 

 inaccessible, or a weir may be constructed by cutting- 

 through rock wliich would be su{)posed to be too costly, 

 until it is remembered that the stone excavated will be 

 wanted for the head works and for facing the dam. A low 

 spui* may run out from a range of hills, and it might appear 

 as if the length of the dam would be excessive, but on 

 investigation it may be found that this spur is just about 

 the height of the dam proposed to be erected. But the 

 discrimination of all these points can only be acquired by 

 practise, united with natural capacity, and no theoretical 

 knowledo-e will enable a man to select a site. 



To sum up, therefore, what is necessary to be done in order 

 to carry out irrigation, and thus raise the value of land 

 many-fold, it Avould ap])ear desirable that Government 

 should take in hand the stoi'age of water, so as to avoid 

 any jealousies and conflict of intej-ests. The storage should 

 be on high ground, and well up the rivers or streams, as 

 there can be no question as to the right of Government to 

 intercept the rainfall of its own land, and numberless 

 disputes may arise as to the proportion which may be 

 intercepted ov taken from a river. All works of this 

 description should be arranged so as to be reproductive 



