HALIFAX WATER WORKS. JOHNSTON. 95 



eastern one and 6.6 gallons per minute from the western one. 

 As the results of the improvements made in 1892 these leaks 

 have been very materially reduced, in one case a flow of 2 

 inches over the measuring weir dwindling to inch and the 

 other stopping altogether. 



When Lower Chain Lake was raised in 1894, a new dam 

 was constructed outside the existing one. It is practically two 

 dams joined by a natural hill, the north one also having a hill 

 projecting into and buttressing it. The north Bart of the dam 

 has a concrete core-wall 4 feet wide on top and 6 feet at bottom 

 carried down to the solid ledge-rock and continued into the 

 banks on each side and running through the waste- weir. The em- 

 bankment is formed of gravel and loam laid in thin layers and 

 well compacted. The old 12-inch pipe used to let down water 

 to the mill owners runs through the dam, also the 24-inch main 

 to the pipe-house, which is at the foot of the outer slope. A 

 leak developed where the 24-inch came through the core-wall, 

 but it was repaired with concrete and has shown no signs since. 

 The length of this dam is 550 feet, the top width 12 feet. The 

 outer slopes are 2 to 1, and the inner 3 to 1, paved with heavy 

 stones. The waste- weir is at the northern end of the dam at an 

 elevation of 206 feet, and is of similar design to the Long Lake 

 weir, the dimensions being 16 feet long, width of crest 3 feet, 

 and a fall of 9^ feet broken by a ledge 5-J feet from the crest. 

 The apron is paved with heavy granite slabs and concrete. A 

 20-inch exit pipe runs through the weir to be used as a waste 

 pipe. The south part of the dam is constructed to the same 

 design as the northern part, with a gate-house in the centre of 

 it. The top and outer slopes of both this dam and Long Lake 

 dam were covered with street sweepings hauled from town and 

 sown with grass seed and in a year were covered with a. strong, 

 thick sod. There are two small dams between the two Chain 

 Lakes, the south one built in 1883, with a sluice 24x36 at ;i 

 level of 194.70; the north with the old waste-weir built in 

 1886. 



