Barr.—On the Taieri Floods. 113 
only in connection with the Taieri, I shall simply refer to them at that stage 
when we come to view the storage room on the lower parts of the plain, and 
shall devote this portion principally to the nature of the larger river and its 
floods. 
A comparison of the Taieri with the chief rivers of Europe or North 
America will show that in proportion to the country drained it is much in 
excess of the most of these as a flood producer. Thus, while it pours down its 
water at the rate of 1:666 cubic yards in the second for each square mile 
drained above Outram, the Mississippi in flood flows only at the rate of 0-044 ; 
the Ohio, at its mouth, 0-122 ; and the Yazoo 0'372 cubic yards per square 
mile drained. In Great Britain, the Tyne is the only one which approximates © 
to the Taieri in this respect, its rate of. flood discharge being 1-12 ; but small 
streams which have been gauged in meadow land have yielded as much ad 1-2, 
The Yellow River, in Ireland, is as high as 4:12. On the continent of Europe 
the Loire appears to be pre-eminent for its floods—yielding at Pont de Fleurs 
as much as 4:18 cubic yards per second for each mile drained. Many of the 
Indian rivers far exceed any of the above—the Irvitz, especially, delivering at 
the rate of 16-5 cubic yards per second for each square mile of its gathering 
ground. 
Now these figures of course represent very rough comparisons between the 
several streams named, no two of which are alike in physical conditions, 
either as to amount of rainfall or configuration of drainage area; but in 
a general way they enable a classification to be made which may yet be 
further improved as information is gathered. Apart from the relative 
quantities of rainfall, there are many other circumstances which tend either to 
aid or impede floods. Thus a stream draining a large tract of country is much 
less liable to heavy floods than one draining a small one ; and also the general 
nature of the country as to inclination has a most noticeable effect upon the 
rate at which the water finds its way to the river, and consequently a like 
effect upon the amount of its volume. Another most important consideration 
is the nature of the strata, or the amount of vegetation in the district drained ; 
for when the rocks are of a close compact nature, with comparatively few 
joints or crevices, and the ground bears but little vegetation, the water will 
run quickly off ; but where the ground is porous, and the vegetation rank, a 
much longer time will elapse before the underground basins are filled, and the 
ground so saturated as to shed the water off as the rain falls. Surface lakes 
have a comparatively greater effect in moderating floods than either of the 
above causes, by receiving the water as it comes from the creeks, and allowing 
it to spread in thin films instead of rushing down a river channel in deep 
volumes. 
Having got these general results, we may now endeavour to examine 
P 
