116 Transactions. 



For this purpose it will be necessary, in the absence of particular data, to 

 assume that the Waipori river and Silverstream delivered their waters at the 

 same rate as the Taieri, in proportion to area ; and for the general purpose of 

 this investigation that will be enough. This would show a total outpour from 

 these sources of 5,532,900 cubic feet per minute ; and deducting from that 

 amount 1,186,900 cubic feet, which coidd flow towards the sea, the amount of 

 water which would be dammed back would be 4,548,000 cubic feet per 

 minute, representing the rate of rise of the flood. But it has been ascertained 

 that on this occasion 4,585,996,800 cubic feet were the total flood waters, so 

 that dividing the one quantity by the other we would have a period of flood 

 equal to seventeen and a half hours. Of course, this is to be regarded as 

 simply a hypothetical statement which will represent only the average rise and 

 length of time resulting from that, for it is very likely that the rise would be 

 at this rate only for a few hours, which would consequently necessitate a more 

 lengthened period to produce the same total accumulation from a smaller rate 

 of increase. 



We have now to consider the amount of water which it would be desirable 



to prevent flowing upon the plain by the Taieri river, in order that the floods 



may not attain to such an extent as to overflow the banks. It has been found 



that the damage caused about the West Taieri has been the consequence of 



the small section of the river further down not being suflS.cient to carry off" the 



whole waters as they arrived ; and it has been shown by Mr. Thomson that 



the smallest section has been able to pass down 1,173,744 cubic feet per 



minute ; but it might not be safe to charge it with even this quantity, so we 



will leave a considerable margin by taking it only to the extent of 900,000 



cubic feet, looking to store the remainder in the Upper Taieri lake, or upon 



some of the tributaries of the river, such as the Deep, the Sutton, and the Lee 



streams. It will be observed that this makes no provision for the waters of 



the Silverstream, or the Waipori river. The first of these could probably be 



stored in the lagoon near its junction with the main river, and which is 



evidently the natural flood moderator of that stream, or in some reservoir 



higher up ; while the large flow from the Waipori would be allowed to spread 



over that and the Waihola lakes. The general result, then, may be arrived at 



thus : — 



At Feet per Min. 



The quantity poured down the Taieri ... ... 900,000 



„ „ „ Waipori ... ... 730,000 



1,630,000 

 Outflow to sea ... ... ... ... 1,187,000 



443,000 



