Buildings and Yards. 519 



fifty feet above the highest faucet, and that the flow is sufficient so that 

 a bath-tub of water can be drawn at the rate of four gallons a minute. 

 Then if the pipe line is 1,000 feet long, the one-half inch pipe would be 

 out of the question, since it would take over 500 feet elevation to get 

 that amount of water through the pipe and the pipe would not stand that 

 pressure even if it were available. The inch pipe, on the other hand, 

 needs but 16 feet to make the water flow at the rate given. 



If the source of supply is to be a brook, whose purity has been es- 

 tablished, it will be sufficient to lay a pipe into the brook, protect the 

 end by a strainer (being careful to tamp the dirt back well in the trench 

 in which the pipe is laid). It may be that the brook runs dry in the 

 summer time and storage of the spring floods is necessary. This can 

 readily be done, under certain conditions, as follows : Suppose the length 

 of time during which the stream may be dry is fixed at 100 days, then 

 the storage supply must be 300 times 100 or 30,000 gallons. In order 

 that the water shall not become stagnant and offensive, the pond or reser- 

 voir in which the water is stored must be at least ten feet deep after this 

 amount has been drawn ofif. This requires, for economy, a narrow gorge 

 or gully in which to construct the reservoir. If a suitable site can be 

 found, its fitness may be tested as follows : Take the average width of 

 the gully, suppose it to be twenty feet, and multiply that by the length 

 of the pond to be formed, suppose that to be 200 feet. The area of the 

 pond then, with a ten-foot dam, would be 4,000 square feet, or 

 4,000 cubic feet for one foot depth. The storage of 30,000 gal- 

 lons, or 4,000 cubic feet, will then require one foot extra depth for 

 actual consumption. But evaporation from this water surface will take 

 place rapidly during the summer months and it will be necessary to have 

 about eighteen inches additional for this purpose, or two and one-half 

 feet (above the ten feet) in all. Such a computation as the above may 

 enable one to use a brook, even if quite dry in the summer, as a source 

 of supply throughout the year. 



The method of constructing a dam for the reservoir described above 

 will depend on the soil, the money available, on the permanence desired 

 and on the opportunity for overflow. If the bottom and sides of the 

 gully are rock, then a rough stone or concrete dam, about twelve feet high, 

 designed to allow the water to pour over the top, would be suitable. It 

 should be at least six feet thick at the bottom, two feet thick at the top 

 and, if logs or ice are likely to be brought down in the spring freshets, an 

 oak timber should be bolted into the top to prevent injury to the masonry. 

 If the banks are firm gravel or sandy loam, an earthen dam, six feet wide 

 on the top and sloping two horizontal for each foot vertical both up and 

 down stream, will be suitable. 



