BUILDING SMALL RESERVOIRS 47 



or cultivating to a depth of eight inches and then admitting water 

 slowly and keeping the teams going with the harrow. Begin at the 

 center and work round and round until the mud becomes as smooth 

 as pancake batter, working and reworking away from the center 

 until the puddle is carried well up the sloping bank. This puddle 

 layer, if the soil is fitted for it, will make the pond hold water. 



A Small Reservoir in Sandy Soil. The foregoing construction 

 will not hold water if the materials are too coarse in character. 

 Where percolation is free a water-tight covering for the bottom and 

 banks must be provided. This can be done by hauling in clay for 

 a puddle or the reservoir after shaping may be cemented. In parts 

 of the state where asphaltum is abundant this material is very satis- 

 factorily used, the asphaltum being melted, mixed with the sand and 

 spread on hot and smooth down well with hot shovels and hoes. 



Cement can be used in the form of a mortar made of six parts 

 sharp clean sand to one part Portland cement. Apply two coats, 

 and then brush over with a whitewash of clear cement and water. 

 It is not necessary to make walls of brick or stone on which to 

 cement. Cement directly on the earth, even if it be sand or gravel, 

 answers perfectly. As we have no earth-freezing such work is safe. 

 If there should be cracks, give a coat of clear cement and water 

 and it will close them up. But cracking should be prevented as far as 

 possible by being sure that the earth is well settled before cementing. 



The use of clay puddle is also very satisfactory. The following 

 is the plan of construction followed by Mr. Edward Berwick, of 

 Carmel valley, Monterey county, in building a reservoir which stood 

 thirty years of constant use : 



My reservoir is eighty feet in diameter and made on land with a slope of 

 say one in forty. I drove a peg in for a center, took a forty-foot line and 

 marked a circle. I dug a trench eighteen inches in width, say three feet deep 

 where the land level was lowest and five feet where it was highest, so that 

 the ditch bottom was level. I filled the ditch with puddled clay, well tamped, 

 then excavated a width of perhaps ten feet, just inside the clay ring, to 

 the level required for the reservoir bottom. I lined this ten feet of floor 

 with clay, being careful to unite the clay of the ditch ring with this floor. 

 Then began clearing out the middle of the reservoir and banking up on 

 this ten-foot floor, and also on outside, at the same time adding clay to the 

 ditch ring as the embankment grew. 



When the required excavation was made, cleared up well to the edge of 

 the ten-foot wide floor, I put in the clay for the rest of the bottom, uniting it, 

 of course, with the ten feet already laid, but now covered with the inner em- 

 bankment. A three-inch discharge pipe was laid at the bottom, with neces- 

 sary fittings. 



The reservoir is nearly seven feet deep when filled, and forms an excel- 

 lent bathing tank for the family in addition to its irrigation service. 



This is a very thorough style of construction. It would be 

 cheaper to excavate as described in the previous list of suggestions 

 and then trust to a clay layer evenly spread over the bottom and 

 sloping sides, but the use of the puddle trench and flat floor is surer 

 to hold water. The puddle trench is carried to the top of the bank ; 



