LOSSES OF WATER 207 



made the better, for many reasons, but especially on account of the 

 temperature of the water. That of springs is generally too low in 

 summer for immediate use, and its value is greatly enhanced by 

 being raised to an equal or greater temperature than that of the 

 air. This is quickly done by exposure in a shallow pond. A res- 

 ervoir can be constructed entirely in the ground where the slope 

 will admit of it, and by lining the bottom and sides with clay well 

 puddled, will answer for most purposes. Some are built of adobe, 

 backed with earth and plastered on the inner side with hydraulic 

 cement. Concrete of lime, sand, and broken stone, is, however, 

 the best material, where lime can be readily obtained, and any 

 person with ordinary mechanical skill can construct them. The 

 following hints on a dirt reservoir may be suggestive : 



A reservoir should be built on the highest part of the tract sought to 

 be irrigated by scraping the earth from the outside and from such a large 

 area as not to affect the utility of the land from which it is taken. With a 

 levee all around 5 feet high, 5 feet of water could be carried safely. The 

 slopes ought to be two to one on the inside. A reservoir 20 feet square 

 and 4 feet deep would hold 12,000 gallons. With the slopes as above the 

 reservoir should be measured 2 feet from the bottom, or half way up the 

 4 feet of water; consequently to lay out a reservoir to hold 12,000 gallons, 

 put the stakes 12 feet square and build. For any other size one take 8 feet 

 off the same as in this. A reservoir 25 feet square will hold 18,750 gallons 

 and would be 17 feet square at the bottom; one 30 feet square would hold 

 27,000 gallons and would be 22 feet at the bottom; one 3"5 feet square 27 

 at the bottom will hold 36,000 gallons; one 40 feet square 32 on the 

 bottom will hold 48,000 gallons. This spread upon the surface of an 

 acre would be a little more than 1% inches of rainfall. 



Almost any loam soil will hold water with a little puddling. The cheapest 

 way to puddle is to build a pen the size of the intended reservoir, including 

 at least a portion of that to be under the embankment, wet it very wet, 

 put some hogs in the pen and keep feeding them barley, a little at a time, 

 so as to make them not only walk around but root for the barley. A half 

 sack of barley fed to eight or ten hungry hogs in half a day will make a 

 good puddle. If it did not work satisfactorily the water could be taken off 

 and the bottom covered about an inch deep with coarse sand mixed one 

 part to five with Portland cement, put in dry, and let it be covered slowly. 

 A barrel of cement may be counted at about 4 cubic feet and with the 

 mixture above would cover the first-named reservoir about \Y^ inches. This 

 would make it tight. The supply pipe should come up from the bottom, so 

 that the lift would never be more than the height of the surface. 



Loss of Water by Seepage. The great loss of water by seepage 

 during a long run has led to the cementing of ditches, and to the 

 use of miles of large wooden, concrete and iron pipe by the irri- 

 gation companies of Southern California ; also, where the slope is 

 rapid, paving ditches with rock has been resorted to. Similar 

 efforts naturally suggest themselves to the user of a small water 

 supply to save his flow from loss. The lining of ditches to prevent 

 seepage is being tested by the California Experiment Station at 

 Berkeley, and publication of results is being made.* Where lumber 

 is cheap the use of a board flume is an available means of saving 

 water, when the soil is coarse and leachy. 



Bulletin 188 University of California Experiment Station. 



