Yan Yean Water Works, 



201 



to obtain tliose required results which we have now the honour 

 of presenting to you, as representing such amounts of dis- 

 charo;e ai^ si pply as are safely warranted by our calculations 

 and dedu^tiors, 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 BiDer Flenty. 



Cube Yards. 



Original supply by rainfall of 31 incbes, on basin of 



60 square miles 160,042,666 



Loss from same — 



By absorption and evaporation over 



surface of basin, at tbe rate of Cube Yards. 



57 6 per cent, of rainfall ... 92,184,564 



By evaporation in swamps 4,194,804 



Maldng tbe total loss 96,379,369 



Wbicli loss deducted from tbe original supply by rain- 

 fall, gives the total discbarge of tbe Plenty, per 



annum, above tbe reservoir, equal to t>J,bbi5,^y/ 



The half of this last amount being assumed as tbe 

 ' greatest quantity tbat can be judiciously abstracted 



from tbe Plenty, will represent tbe total supply to 



the reservoir from tbe Plenty basin, equal to ... 31,831,648 



Cube Yards. 



Supply from Basin of Besertoir. 



Supply by rainfall of 31 inches, on basin of 3,000 acres, 



draining into reservoir 12,^06,666 



Loss on same — from absorption and evaporation 

 over surface of basin, at tbe rate of 57*6 per 



cent, of rainfaU 7,201,324 



Which amount of loss, deducted from rainfall, repre- 

 sents tbe amount of drainage into reservoir from its 



basin, equal to ... 5,302,009 



Supply from Bainfall on Beservoir, 



^■^ Cube Yards. 

 Uainfall of 31 inches, on 1,460 acres, superficial extent 



of reservoir, equal to 6,084,955 



Total of various Supplies into Beservoir. 



Cube Yards. 



Supply from basin of River Plenty 31,831,648 



do. reservoir ... ... 5,302,009 



Do". rainfall on reservoir 6,084,955 



Total of supplies in reservoir 43,218,612 



Z 



