THE STATE OF THE MELBOURNE WATER SUPPLY. LXXV. 
River, which is crossed on a wrought iron girder bridge, 
all the syphons are laid under the beds of the streams. 
At each of the charging and discharging basins, provision 
is made for connecting a duplicate syphon. Each of the 
syphons is provided with a scour pipe large enough to take 
the full flow of the aqueduct, enabling the water to be 
directed down any of the natural water courses when it 
becomes necessary to empty any lengths of aqueduct for 
cleansing and repairs. The tunnels are constructed to 
earry 50 million gallons per day, but the aqueducts and 
syphons are only now arranged for 25 million gallons, but 
by constructiug the duplicate syphons, and raising the 
side slopes of the open channels the necessary increase to 
50 millions can be readily obtained. 
Preston Reservoir.—Both the Yan Yean and Maroondah 
systems unite in the Preston Reservoir where the water 
is distributed to the central parts of the Metropolis. This 
reservoir is constructed partly in excavation, partly in 
bank, and is lined with bluestone pitchers, the side slopes 
being 1} to 1. It is 20 feet deep, and holds 16 million 
gallons. 
The Yan Yean reservoir witha by-wash level of 602 feet 
governs the whole Metropolitan area by gravitation. The 
Maroondah system only delivers into Preston reservoir at 
328 feet. 
Average daily consumption for each month from 1891 
to 1903: 
Average 
|Maximum 
Minimum 
Average 
January. 
February. 
33093436 
37821998 
28306891 
July. 
21321399 
| Maximum]! 343419226 
Minimum! 17273423 
‘34666704 
41630304 
284988 14 
August. 
22127792 
26580548 
18110390 
March. 
30185718 
33610839 
25008731 
September. 
22664674: 
27135736 
19534740 
April. 
25211126 
2856290C 
21280987 
October. 
25067122 
29047355 
21836103 
May. 
22520842 
27147129 
19412690 
November. 
29339076 
34956667 
25177922 
June. 
21287286 
25689700 
17036021 
December, 
33101834 
38276258 
285750411 | 
