Hiecixsox.—On Floods in Lake Districts. 187 
from cattle. How much simpler would it have bien to have reserved the 
original bush ! 
I do not suppose that the banks of the rivers on the Canterbury plains 
have been ever wooded—certainly not since the settlement of the country— 
and I doubt if this method of planting would be of any avail in their case, 
as the impetuosity of the floods and loose character of the banks would be 
fatal to the growth of plantations. In some places willows have been 
planted as a protection to the railway banks, and promise to succeed, though 
had they been introduced on a larger scale there would have been a better 
chance of ultimate good results. It is only in the lower reaches of these 
rivers that they break over their banks, as they flow for the greater portion 
of their course across the plains between well-defined terraces, which 
gradually die out when the sea coast is approached. 
As the slope of these river-beds generally becomes less upon nearing the 
sea, the consequent reduced velocity of the current affords a better 
opportunity for trees to succeed if exposed to it. Upon approaching the 
hills the velocity and consequent strength of the current during floods may 
be'instanced in the case of the late rise in the Rangitata, where square 
blocks of concrete, nearly two tons in weight, were carried upwards of a 
quarter of a mile down the stream. In such a position no tree-planting 
*could be of any avail. 
The construction of storage reservoirs, in imitation of the lakes alluded 
to at the commencement of this paper, seems to me the most effectual 
manner in which to control floods, and which would at the same time arrest 
the shingle perpetually travelling from the mountains to the sea. This 
travelling shingle is generally the cause of diversions of the rivers from their 
proper course. An obstacle, such as a fallen tree grounding in the bed, 
causes & reduction in the velocity of the current, immediately causing 
the shingle in motion to deposit behind it; this shingle bank will increase 
in size till it causes the stream to branch off in a new direction, in many 
instances to the destruction of valuable land. 
In the case of the storage reservoir on the River Furens, one of the 
latest examples (as previously alluded to), it was constructed of sufficient 
capacity to impound sixty-five per cent. of the average yearly rainfall. 
This was a most extravagant manner in which to arrest the floods, though 
most effectual. It, however, was so constructed for the double purpose of 
storing water, for supplying power, and for use otherwise in the manufac- 
turing town of St. Etienne situated immediately below it. It was thus 
made remunerative. The cost is stated to have been £63,600, and it is 
paying two-and-a-half per cent. on that amount. Had it been constructed 
only for the purpose of regulating the floods in that river, it need only have 
