646 PROCEEDINGS OF SECTION J. 



wide and five feet six inches high. For a distance of eight chains 

 the invert is consti'ucted of sandstone concrete on a sand founda- 

 tion, the extra foundation being required on account of the unstable 

 condition of the natural bottom, consisting of soft yielding silt. 

 The invert for this portion is covered with a bluestone concrete 

 arch struck with three centres. The remaining portion, a distance 

 of twenty-four chains, consists of sandstone concrete for invert 

 and side walls, covered with rolled girders and buckled plates ; 

 the interior of the channel is rendered with cement mortar. The 

 channel is provided with flushing and silt basins. In order to 

 provide for the discharge of storm-water from a portion of the 

 southern slope and to abolish an old polluted ditch, a storm-water 

 sewer was constructed along Dowling-street from the head of 

 Shea's Creek to join with a length constructed by the Eedfern 

 Council. This sewer is entirely constructed of concrete ; the 

 length is thirty-seven chains and four feet six high by three feet 

 six inches wide. Where the sewer crosses the main outfall an 

 intercepting point is fixed in such a way that any sewage passing 

 down is carried by the outfall to the sewage farm. Storm water, 

 by its great velocity, is carried over the openings and discharged 

 into Shea's Creek. All the manholes on this section can be used 

 as flushing stations. 



BAPTIST ESTATE STORM-WATER SEWERS. 



In order that this portion of the system may be relived from 

 storm-water and the dangers arising from the existence of a foul 

 ditch in a populous neighbourhood, a system of storm- water sewers 

 was carried out, consisting of 13.5 chains of a circular section four 

 feet in diameter, and 6.36 chains of oviform section three feet six 

 inches high by two feet nine inches wide, each constructed of con- 

 crete and rendered on the inside with cement mortar. Again 

 thirty chains of stoneware pipe twenty -four inches in diameter 

 have been connected with the main sewer by means of bi'anches. 



The whole system of sewerage is amply provided with manholes, 

 lampholes, and street gulleys, and it is proposed to add special 

 ventilation shafts and syphon flushing tanks as the system is 

 extended. The author has visited the works described for the 

 southern section at various times during their construction, in 

 company with the engineer, Mr. J. Small, M. Inst. C.E., and can 

 testify to the substantial character of the work. The northern 

 and southern sections are now provided with outfalls for their 

 sewage, and the various works for connecting the districts which 

 they are intended to drain are in progress. There still remains a 

 large area known as the Western Suburbs, which it is proposed 

 to drain independently of the existing systems. The area referred 

 to includes ten thousand six hundred and thirty -two acres embrac- 

 ing the following municipalities : — Marrickville, St. Peters, Ash- 

 field, Bur wood, Strathfield, Concord, Five Dock, Canterbury, and 



