USE, CONSTRUCTION, AND COST OF SERVICE RESERVOIRS. 



157 



larger tank than those before described, but its construction is 

 very similar, it is not however roofed in. 



The dimensions and cost of these tanks are as follows : — 



No. 



1 



Dimensions. 



Height. 



Avail. Cap. 

 in gals. 



Cost per 1000 gallons. 



22'6diam. 1210 deep 



65 feet 



31,350 



<£47 lis. Id. vert, iron column 



2 



22'6 „ 1210 „ 



65 „ 



31,350 



<£49 4s. 4d. vert, iron column 



3 



22'6 „ 13'6 „ 



65 ,. 



32,900 



,£57 18s. inclined iron column 



4 



20' „ 11 '6 „ 



34 „ 



20,000 



<£48 5s. timber columns. 



5 



35' „ 18' 



30 „ 



100,000 



.£21 4s. brick piers, uncovered 



Here the comparative economy of large tanks becomes apparent, 

 however in comparing Nos. 1, 2, and 3 with No. 5 not only has 

 the difference in capacity to be allowed for, but it must be borne 

 in mind that they are erected at over twice the elevation and that 

 they are roofed in. Another very important factor in this par- 

 ticular case is freight, the first three were erected at distances 

 varying from five hundred to seven hundred and fifty miles from 

 Sydney, this added quite fifty per cent to their cost. 



In all cases when comparing the cost of various Reservoirs 

 allowance must be made for the cost of material and labour in the 

 locality. The prices quoted are the actual cost of the Reservoirs 

 as constructed. Had the same work been carried out in another 

 town where materials are cheaper or more easily obtained the cost 

 would naturally be less. All the circumstances have to be taken 

 into consideration before deciding whether to use brick, concrete, 

 or iron when designing a Reservoir for any particular locality. 



Type F., Plate xv. — Circular steel tanks, concrete bottom, no 

 cover and standing on the ground. The need for storing a large 

 body of water above the surface of the ground, and thus making 

 the most of the available head, suggested this form of tank, and 

 where such a need is a desideratum this type promises to be very 

 suitable. 



Plate xv., shows some of the details of construction. Four 

 tanks of this form have been built, and being all the same as 

 regards detail of construction, although varying in size, only 

 one need be described. The whole of the steel used in these tanks 



