184 Transactions. — Miscellaneous. 



be between 1,000 or 1,200 feet, wliich is sufficiently near to support my 

 theory. I do not attach any scientific importance to what I have described, 

 though, there being reasons for every function of nature, it is both interesting 

 and our duty in the cause of science to seek for and obtain an explanation 

 of those reasons. 



While considering the magnitude of the floods in these mountainous 

 districts, I should like to draw attention to a fact that I have no doubt is 

 well known to most of you, namely, the beneficial effects that these lakes 

 exert in restraining the rush of heavy floods. They act as reservoirs, in 

 which are stored up the enormous bodies of water pouring off the 

 precijoitous sloxDes of the mountains, gradually allowing it to find its way to 

 the sea in restrained quantities. They also do good service in arresting 

 the shingle and debris washed off the hills, and carried into the torrents by 

 glaciers and land- slips. 



Taking the case of the Molyneux, or, as it is generally termed, the 

 Clutha, it requires no great stretch of imagination to picture to oneself what 

 the aspect of the lower valleys would have become were it not for the 

 influence exerted over the floods by Lakes Wakatipu, Hawea, and Wanaka. 

 These valleys would, in all probability, have been deserts of shingle and 

 sand where not water. 



The Elvers Eangitata, Eakaia, and Waimakariri, in Canterbury, have 

 few lakes on their tributaries — the former and the latter none of importance 

 whatever. The nature of their beds is well known, and requires no 

 description by me. They are a continual source of anxiety to' the settlers 

 in their proximity, as the flood-channels alter their course during each 

 successive flood, inundating and destroying the land near them, and costing 

 large sums of money annually in endeavours to restrain and control them. 



There are many other smaller rivers in both islands having somewhat 

 the same characteristics, and which almost annually do great harm 

 both by flooding and encroaching on the cultivated land near the banks ; 

 consequently the question of how they should be treated, in order to 

 regulate and control them, becomes more and more serious, as it is, I 

 believe, an established fact that the high floods are becoming still higher, 

 as well as oftener repeated. 



We need not go far to seek for an explanation. The rapid destruction of 

 timber and brushwood along the banks will give rise to encroachment, as on 

 the Hutt Eiver. The extensive bush fires on the ranges, and even the 

 felling of timber for use, allows the heavy rains to flow more quickly off the 

 surface into the streams, as, consequent upon the destruction of the larger 

 trees, the smaller ones perish. As a bush country becomes settled and the 

 timber cleared, so will the floods become more violent in then- nature ; and, 



