USE, CONSTRUCTION, AND COST OF SERVICE RESERVOIRS. 



153 



Type C, Plate xiv. — Circular, walls of brick, partly vertical 

 and partly curved inwards to form a portion of the arching, re- 

 mainder of covering consisting of annular coke concrete arches 

 carried on cast iron ring girders resting upon brick piers in one 

 case, but in all others on cast iron columns, formed of two water 

 pipes having their spigot ends connected with a pipe collar — the 

 lower socket end resting upon a dwarf brick pier, and upper socket 

 fitted with a shoe to carry the girder. The pipes being filled with 

 cement concrete — pipes used in this way are found to make a 

 cheap and efficient pier for small Reservoirs. Top of arches 

 covered over with soil, sloped down to meet the filling round the 

 sides. 



Of this type we have four instances, the sizes and cost are as 

 follows : — 



No. 



Dimensions. 



130' diam. 26' deep 

 80' „ 15' , : 

 65' „ 20' , : 

 65' „ 20' , 



Avail, cap. in gals. 



2,157,800 

 383,000 

 381,000 

 381,000 



Cost per 1,000 gals 



£5 9s. 4d. 

 £8 7s. 2d. 

 £8 19s. Id. 

 £8 19s. 6d. 



Type C 1 . — Two small underground Reservoirs have been con- 

 structed where only a small storage was necessary, they correspond 

 nearest to Type C, but the roof is in one span, in both cases they 

 were deep in shale or rock excavation. They were built with 

 vertical walls, concrete floor and a brick dome roof in one span. 



From the table of cost it will be seen that they are not an 

 economical Reservoir, indeed no very small Reservoir can be, 

 comparatively speaking economical. The sizes and cost are as 

 follows : — 



No. 



Dimensions. 



30'diam.20'deep 

 30' „ 20' „ 



Avail, cap. in gals. Cost per 1,000 gals, 



63,200 

 63,200 



£14 13s. Od. 

 £14 16s. 2d. 



Type D„ Plate xiv. — Circular, vertical brick walls carried up in 

 the form of a parapet wall above water level, covered over with 



