Van Yean Water Works. 201 
to obtain those required results which we have now the honour 
of presenting to you, as representing such amounts of dis- 
charge and supply as are safely warranted by our calculations 
and deductions, while we are not prepared to state that they 
embrace the actual or total amount of same. 
The following is a summary of the results of our calcu- 
lations :— 
Supply from Basin of River Plenty. 
Cube Yards. 
Original supply by rainfall of 31 ae on basin of 
60 square miles ane Pf s.. 160,042,666 
Loss from same— 
By absorption and evaporation over 
surface of basin, at the rate of Cube Yards. 
57 6 per cent. of rainfall . 92,184,564 
By evaporation in swamps ... 4,194,804 
——w 
Making the totalloss ... ... 
96,379,369 
Which loss deducted from the original supply by rain- 
fall, gives the total discharge “of the Plenty, per 
annum, above the reservoir, equal to 
The half of this last amount being assumed as the 
greatest quantity that can be judiciously abstracted 
63,663,297 
from the Plenty, will represent the total supply to 
the reservoir from the Plenty basin, equal to 
Supply from Basin of Reservoir. 
Supply by rainfall of 31 inches, on basin of 3,000 acres, 
draining into reservoir 
Loss on same—from caer ue oT ea 
over surface of basin, at the rate of 57°6 Lg 
cent. of rainfall 
31,831,648 
Cube Yards. 
12,503,333 
7,201,324 
Which amount of loss, deducted from ‘rainfall, repre- ° 
sents the amount of drainage into reservoir from its 
basin, equal to a; sels And eke 5,302,009 
Supply from Rainfall on Reservoir. 
Cube Yards. 
Rainfall of 31 inches, on 1,460 acres, superficial extent 
of reservoir, equal to . oa Aa 
——————awe 
6,084,955 
Total of various Supplies into Reservoir. 
; Cube Yards. 
Supply from basin of River Plenty -- 31,831,648 
Do. do. reservoir ... eae ht 5,302,009 
Do. rainfall on reservoir aes aire wee 6,084,955 
Total of supplies in reservoir... .. 43,218,612 
— 
