94 HALIFAX WATER WORKS. JOHNSTON. 



stones, the too of the inner slope to be composed of coarse 

 gravel and small stones ; the level of the waste- weir (which 

 was a wooden structure) to he 200.00 feet above mean low tide. 



In 1877 the dam was raised and strengthened by putting 

 rafts of brushwood and straw covered with fine material in front 

 where leaks had developed, and raising the dam five feet, 

 widening the top to twenty-four feet and flattening the outer 

 slope to Q l\ to 1. The water side was protected by a heavy 

 sloping wall surmounted by a granite coping 18 inches high and 

 forming a low wall along the front. The dam was lengthened 

 to 1,018 feet to the west of the waste-weir. In 1892 the dam 

 was raised two feet and strengthened by depositing 5,000 

 cubic yards of good material da the face. The present waste- 

 weir at a'n elevation of 205.99 feet above low tide was con- 

 structed in 1878 of massive granite masonry and strengthened, 

 in 1888 by the addition of a. concrete wall at the front. It is- 

 62 feet 6 inches long and the crest is 3 wide and level, the fall 

 from the crest to the apron being 3-J feet. The latter is con- 

 structed of granite slabs about six feet long with granite pav- 

 ing outside. There is a sluice-way closed with an iron gate at 

 the eastern end, 62 inches wide and 50 inches high and at a 

 level of 198.90. 



In December, 1905, iron staunchions were secured to tlio 

 top of the weir and the sill raised one foot, or to an elevation 

 of 207.00 by placing two 6-inch timbers in position. 



The highest level to which the water has risen over 'che 

 weir is 25 inches on the 19th October, 1S96. 



In 1873 leaks were reported in the Long Lake darn by the 

 city engineer, and in June, 1877, thermoinetrical observations 

 were taken in the lake and at each of the runs of water along 

 the foot of the dam, when it was found that the two largest 

 runs were from leaks and the rest from springs under the em- 

 bankment. Weirs were placed on these, and the actual amount 

 of leakage was found to be 14.7 gallons per minute from the 



