- DAMAGE BY FLOODS IN RIVERS PREVENTION. 645 
these will not necessarily receive any benefit from the floods 
being lowered in the intermediate part. ‘ 
Some 20 years ago there was much discussion about 
abating floods by retaining them in reservoirs of sufficient 
dimensions. I think the French engineers were those who 
took most interest in this question ; but I noticed that they 
never had the courage to put it in practice. In 1878 the 
late Mr. H. P. Higginson and I were instructed by the 
New Zealand Government to investigate a proposal to 
abate the disastrous effects of the floods of the Taieri River 
in this manner. We found an excellent site for a dam, 
and calculated the height it would require to be to contain 
the waters of a great flood. 
In this case there were two branches of nearly equal size, 
and the problem was to hold back the flood in one until the 
other had time to discharge its flood. This of course is 
quite feasible and probably safe enough if one could have 
a time-table of floods, but on looking up the records we 
found the floods were so uncertain in their times, and so 
devoid of any kind of regularity, that how to deal with a 
flood when one had caught it in a reservoir was the most 
puzzling part of the question. 
Subsequently I investigated, for the New South Wales 
Government, the same question as regards the floods of the 
Hunter River,-and shortly after that Col. Pennycuik, R.E., 
dealt with the same subject in respect to the floods in the 
Brisbane River. It is significant of the uncertainty of 
treating floods in this way that we arrived at opposite 
conclusions in regard to it, and necessarily, from my point 
of view, I hold that the Colonel ignored or made light of 
difficulties which I consider formidable. 
In the Hunter the drainage area of the flood to be stopped 
is greater than the Brisbane, and consequently the capacity of 
the proposed flood reservoirs was correspondingly greater 
than that proposed by Col. Pennycuik for the Brisbane 
River ; in fact, the flood reservoir proposed to hold up the 
floods of the Hunter would haveheld the unheard of quantity 
of 40,000,000,000 cubic feet or 250,000,000,000 gallons, 
which was reckoned to be somewhere about the quantity 
brought down in a flood by the Hunter and its principal 
tributary, the Goulburn, from 5230 square miles of water- 
shed, - 
The proposal was to stop back the water in a great flood, 
and to use it for irrigation at other times. The dam to hold 
this vast quantity of water was to be below the juaction of 
the Hunter and Goulburn, 130 feet high, with eight sluices 
