118 Transactions. 
could be kept back for even twelve hours, their most destructive effects would 
be moderated. It would also be necessary to have reservoirs upon the Sutton, 
Deep, and Lee streams, perhaps more so than in the Taieri, in proportion to 
their areas, as the features of their catchment basins are such as to show many 
indications of rapid flood-producing streams. 
The mode of flood prevention I have examined in this paper is one which 
has been much adopted upon the continent of Europe, and notably upon the 
river Loire, which I have already referred to as standing remarkably high as 
a flood-producer. Above the particular part where the discharge I have 
referred to was gauged, we have seen that it ranks nearly three times as 
intense as the Taieri ; yet to moderate these waters a weir sixty-five feet high 
was erected in 1711, which did immense service in the floods of 1846. They 
topped it, however, by a height of about five feet, but were still sufficiently 
restrained to lessen considerably the damage which otherwise would have been 
sustained. 
The advantages which the prevention of the flow of the waters upon the 
lower plain possesses over any scheme of embankment, either along the 
present channel or any new one, are so evident as scarcely to require remark. 
Besides being much cheaper, it possesses an advantage in this, that even if 
carried out to a partial extent it produces general benefit to all the land which 
has hitherto been liable to inundation ; but by the method of embankment 
upon the plain, intended to shut the water off particular parts, these portions 
are protected only by aggravating the evil upon other spots, both by the 
increased depth of the water and the heightened current. 
One objection to this method has been so often urged that, paradoxical 
though it may appear, I believe that had it been founded upon facts, they 
would, ere this, have been recognized as an argument for its immediate 
adoption. I refer to the belief that, supposing such a work were erected, the 
lake would quickly be silted up by tailings derived from the diggings, so that 
the bottom being raised the weir would speedily become useless. Now the 
area proposed to be occupied by the reservoir is presently about as much 
exposed to those deposits as it would be then, and though some parts are so 
acted upon to a considerable extent, yet had the evil been of such proportions 
as to be practically felt, a necessity would have existed ere this for the imme- 
diate erection of a weir at the outlet, to counteract the shoaling process, and 
thus prevent a more rapid discharge of the water than would be consistent 
with its natural condition. An examination of the locality, however, would 
convince anyone that there is but little to fear from this evil assuming dan- 
gerous proportions ; for, taking the Naseby diggings alone, it will be seen that 
even after about nine years of extensive sluicing operations, during whicb 
the heaviest flood on record has been experienced, the greatest distance to 
