HiGGiNSON. — On Floods ill Lake Districts. 187 



from cattle. How much simpler would it have been 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 then* 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 Eangitata, 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 tlie 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 a 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 du'ection, in many 

 instances to the destruction of valuable land. 



In the case of the storage reservoir on the Eiver 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 ^663, 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 



