- 198 Report of the Commissioners on the 
But it may be objected that the great body of the flood- 
water will so spread over the land and flow past that the 
aqueduct cannot catch its proportion of it, this may be 
prevented by the construction of a low dam of an inexpensive 
character. 
We hence affirm that the aqueduct, with slight additions 
to its lower bank, will be capable of conveying 31,831,648 
cubic yards per annum into the reservoir, with a maximum 
delivery in time of floods, of 1,935,999 cubic yards in twenty- 
four hours, being half the assumed amount discharged by 
the Plenty after a rainfall of one inch within twenty-four 
hours. 
Having thus determined the total amount that can be de- 
livered into the reservoir from the River Plenty, our next 
subject of inquiry is relative to that derivable from the 
drainage basin of the reservoir, and also from the rainfall 
upon its surface, both of which can be arrived at from the 
data already determined on. 
The area of the drainage basin of reservoir is 3,000 acres, 
or 14,520,000 square yards, obtained from Government sur- 
veys, a rainfall of 31 inches on which will equal 12,503,333 
cubic yards; then the amount due to 17°856 inches loss from 
surface evaporation, as before determined, must be deducted, 
equal to 7,201,324 cubic yards, leaving 5,302,009 cubic yards 
derived from surface drainage into reservoir. 
The area of the reservoir itself is 1,460 acres, equal to 
7,066,400 square yards; hence 31 inches rainfall on the area 
would equal 6,084,955 cubic yards. 
Hence the different amounts of supply to the reservoir 
will stand thus :— 
Supply derivable from the River Plenty... 31,831,648 cubic yards. 
Supply derivable from drainage area of 
basin of reservoir wes sao ... 6,302,009 do. 
Supply derivable from rainfall of 31 inches 
on surface of reservoir ... 505 ... 6,084,955 do. 
Total in reservoir “90 ... 43,218,612 cubic yards. 
——— 
This amount, as delivered into the reservoir, is subject to 
the further loss of evaporation from its surface, already de- 
termined at 9 feet of depth for still water, which, over a sur- 
face of 7,066,400 square yards, will give 21,199,200 cube 
yards to be deducted from the last amount, leaving 22,019,412 
cube yards in reservoir. 
