288 PURIFICATION OF PUBLIC WATER SUPPLIES. 



ing. The past winter the cold, though severe, has not 

 been continuous and, from some cause, tjie river was in 

 in an unusually muddy condition. Much of the time it 

 was impossible to filter the maximum rate while the con- 

 sumption was much greater than usual, in some days 

 equaling that pumped. In such cases it is impossible to 

 store water in the reservoir. On January 2d an effort 

 was made to clean the beds, but before they could be 

 drained ice formed and the sand froze so that although a 

 large force of men was employed the entire surface could 

 not be properly cleaned and we were compelled to start 

 pumping with but about three-fourths of the area in 

 order. A similar condition occurred on January 13th, 



The effect of a change of character in the water of the 

 river is sometimes to very unexpectedly stop filtration, as 

 was the case in the early part of this month. Pumping 

 was stopped on Saturday night with the bed working 

 well and the reservoir full. A heavy rain-storm oc- 

 curred on Saturday and Sunday. On Monday it was 

 necessary to make some repairs to the pumping engine. 

 When pumping was resumed on Tuesday the water was 

 so heavily charged with mud that we were compelled to 

 stop on Thursday morning, and then to such an extent 

 were the beds clogged that the water did not drain off 

 sufliciently to permit an attempt at cleaning until San- 

 day morning, and even then not completely. As there 

 was not sufficient water in the reservoir to last over Mon- 

 day a large force of men was employed on Sunday and 

 were just able to finish the work so that pumping could 

 begin on Sunday night. The diflaculties arising from 

 algse growths and conditions of weather could be entirely 

 obviated by covering the beds ; as algae will not grow 

 except in the sunlight and, with proper covering, the sand 

 would not freeze in the coldest weather and but little if 

 any ice would form on the surface of the water. 



We have had many narrow escapes during the past few 



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