THE MOTHER OF WATERS"

Evening Post, Volume CXI, Issue 83, 9 April 1931, Page 10

THE MOTHER OF WATERS"

(To the Editor.) Sir,—Your recent sub-leader, ''The Mother of Waters." raises some interesting questions. Permit me to refer to one or two. Your basic assumption, namely, that the denudation of the mountain ranges results in more severe and frequent floods is so generally made that it is not known to be an assumption. It has, however, been challenged by recognised world authorities on such matters. Daniel W. Mead, after making an exhaustive study of the effect of extensive deforestation in Wisconsin, concluded that the cutting of forests in that State had had no material effect on the high or low water flow ol tho streams or on the frequency of floods. Colonel Cluttendcn pointed out to the American Society of Civil Engineers that under certain conditions forests tend to increase rather than 'diminish the magnitude of floods.' Again, a commission of French engineers came to the conclusion that tho action of heavy forest cover in retarding run-off disappears almost entirely in the great rainfalls that cause the Seine floods. • - : attention should therefore be directed to"other means of controlling.directly the floods in the Hutt Valley, which, as you point out, will be densely populated in the course of years. The most promising method of reducing floods in this valley ia by means of an artificial lake formed by tho construction of a dam across the narrow gorge of the Hutt River some distance below its junction with the Pakuratahi. Some years ago the extent-and capacity of such a lake was carefully determined by the Public Works Department to ascertain its value as a source of^ hydro-electric power. . Such a hydro-elcc-" trie scheme, if linked up with the existing power stations, would by itself have a considerable value. In its double-barrelled purpose its value is much enhanced. H appears to be opportune to revive the project, the more so as its construction would absorb a large amount of reproductive labour.—l am, etc., PLUVIUS.