XXXVI. J. M. SMAIL. 



General description of ivorks. — " The works have a 

 nominal capacity of 32 million U.S. gallons daily, and are 

 capable for short periods of yielding 48 million U.S. gallons 

 daily. The area occupied is 170 feet by 219 feet, outside 

 measurement. The structures are built in concrete on 

 rock foundations. At the west end is the coagulating and 

 subsiding basin, 130 feet long, 42 feet wide, and 43 feet 

 deep on [aside lines, the capacity being If million gallons. 

 At the east end the lower portion of the building contains 

 a clear water basin in two compartments; each, on an 

 average, is 121 feet long, 58 feet wide, and 29 feet deep to 

 the maximum How line for the filtered water. The total 

 capacity of the clear water basin is about 3J million gal- 

 lons. Above the clear water basin there are 32 rectangular 

 concrete filter tanks, 24 feet by 15 feet and 8 feet deep, 

 arranged in four rows of 8 filters each. The total area of 

 filter surface is 11,520 square feet. Between each pair of 

 rows of filters there is a pipe gallery, in which the main 

 pipes, with branches to the adjoining filters, are placed. 

 This gallery is 12 feet wide and 13*5 feet high. Over each 

 pipe gallery there is a platform at a level slightly above 

 that of the water in the filter tanks, on which the attendant 

 stands when operating the filters. There are two wings 

 to the main building, with which they connect. The filters 

 are covered with a flat concrete roof, with a manhole over 

 each filter for access. 



" The coagulating basin is covered with a flat concrete 

 roof, which forms the floor of the main building. This 

 building is 132 feet by 46 feet, and contains the machinery 

 for the rotary blowers and pumps, and devices for applying 

 coagulant, storage for the same, also the laboratories, 

 offices, etc. All machinery is driven by electric motors, 

 the current being generated at the pumping station." 



The method of filtration is conducted as follows: — "River 

 water is taken from the head-race canal and delivered to 



