114 Transactions. 
particularly the conditions of the Taieri drainage ground, with a view to 
ascertain, if possible, in what respects it. facilitates the rapid discharge of the 
rain or melting snow, and it will then be seen that the chief features likely to 
promote this are the generally mountainous character of the catchment area, 
with the exception of the Upper Taieri plain, the steep inclination of the 
ridges, the nature of the rocks, and the general steep declivity of the bed 
between the upper and lower plains. On the other hand the upper of these 
plains forms a natural basin about 280 square miles in extent, but of this 
only about one and a half square miles are an open lake, the remainder being 
deposits of shingle of various depths lying upon impervious clay, and capable 
of being a store reservoir only to the extent of the interstices between the 
stones. That portion, in fact, resembles a huge sponge, acting with the open 
lake in retaining the water, and preventing to a certain extent its sudden 
rush down the channel towards the lower parts. The lake lies,at the flank of 
the Lammerlaw or Rock and Pillar range; and finds along with the Kyeburn 
an outlet through a narrow gorge, at one place not wider than 110 feet, but 
unfortunately its low level limits the capacity of the whole reservoir as a flood 
moderator. The point now is, to consider the practicability of raising that 
outlet to such an extent as to store the greatest flood waters that are likely to 
occur, and release them only at such a rate as shall not be prejudicial to the 
low grounds lying below Outram. 
The flood of 4th February, 1868, being the greatest on record, I shall 
take as the standard one, seeing that it is necessary in any remedial works 
that may be proposed to provide against the occurrence of an evil at least 
equal to that already experienced. 
The circumstances of rainfall attending the floods of J anuary and 
February of that year, at least so far as we can judge the Taieri basin by 
observations taken at Dunedin, were almost such as to lead us to expect that 
no such floods are likely to occur for very many years. Upon examination of 
the meteorological tables prepared by Dr. Burns and the Meteorological 
Department, it will be found that the unprecedented nature of the January 
and February floods was more owing to the extreme degree of saturation in 
which the ground must have been by months of previous rain, than to even 
the heavy rains of any one particular day. Doubtless these were very heavy, 
but not so much so as several days both before and since, which did not 
produce the same rise in the water. For the months of October, November, 
December, January and February, the rainfall ranged from 5-0 to 8-078 in., 
thus showing a continuance of wet weather unequalled, I believe, in the 
history of the settlement. In the case of the flood of January, 1870, which 
did not rise so high as the one we are specially considering, the rainfall 
recorded in one day exceeded that shown upon 4th February, 1868, but that 
