THE IERIGATION AGE. 



107 



(d) Cement mortar plaster 



(e) Heavy road-oil. 

 (/) Clay puddle. 



to 1 inch thick. 



RIVER BOULDEKS SET IN LIME MORTAR AND POINTED 

 WITH CEMENT MORTAR. 



This method has been extensively used in the San 

 Bernardino Valley. Good examples of this type are 

 seen in Eedlands, Crafton, Highlands, and San Ber- 

 nardino. This type of lining was probably introduced 

 in 1882 to 1883, when the Ontario Colony Enterprise, 

 receiving its water from the San Antonio canon, paved 

 its canal, 5 feet wide at the bottom, 6 feet wide at the 

 top, and 2 ! /2 feet deep, with rocks laid in hydraulic lime 

 water and plastered over with cement mortar. This 

 lining was 8 inches thick and cost about 60 cents per 

 lineal foot, or about 6 cents per square foot, which is 

 very much cheaper than the average cost per square foot 

 of this type of work since then. This low cost is prob- 

 ably accounted for by the cheap Chinese labor used at 

 that time, the rate being $1.25 per day; also the small 

 cost of the lime, $1 a barrel, and the rock not having to 

 be handled at great distance. 



The cement plaster was mixed in the proportion 



The ditch is excavated to a definite cross-section, 

 this cross-section being of such size that after receiving 

 a lining of about 1 foot in thickness it will be the re- 

 quired finished cross-section. After the excavation, 

 mold frames with boards are used to guide the lining 

 work; between the mold boards and the sides is a space 

 of 1 foot which is the thickness of the lining. Into this 

 space a layer of cobbles about 1 foot in thickness is 

 built, with the interstices filled with small stones; a 

 grout formed of one part of lime to seven parts of clean, 

 sharp sand is then poured in and tamped in order to fill 

 all voids. The lining of the sides is built up in this 

 manner in consecutive layers 1 foot at a time. The bot- 

 tom is usually paved before the sides, the mold frame 

 resting on the bottom. The lining is generally allowed 

 a few days to harden, then the mold boards are removed 

 and the cement plaster put on. This plaster is a mix- 

 ture of one part cement to three parts of clean sand and 

 is applied about y 2 inch thick, giving a smooth surface. 



The size of the ditch thus lined was 2% feet to 3 

 feet wide at the bottom, about 4 feet deep, and side 

 slopes of about 1 on 4. (Fig. 1.) The approximate 

 cost was 15 cents a cubic foot. The price of labor and 

 materials was as follows : Cement, $3.75 a barrel ; lime, 



Fig. 2. Hemet Land and Water Company's Canal; Lined with Cobbles Set in Cement Mortar. 



of one part of cement to three parts of sand with lime 

 water. The bottom was finished with a thin coating of 

 cement and sand in equal quantities. The lime mortar 

 was one part of lime to five parts of said. 



This type of lining, while largely used since then, 

 is now employed mainly where repairs are necessary. 

 Accurate data as to cost and details of construction are 

 difficult to obtain. A great deal of this work has been 

 replaced with pipes. The new Bear Valley Water Com- 

 pany and also the Crafton Water Company have good 

 examples of this construction. The ditch known as the 

 Highlands ditch, and the Old Eedlands ditch, known 

 as the South Fork ditch, both diverting water from the 

 Santa Ana river, are paved and cemented. While parts 

 of these ditches were first paved with cobbles or rocks 

 without the use of lime or cement mortar, or paved with 

 cobbles or rock faced with cement mortar without the 

 use of lime mortar, the more recent type of construction 

 consists mostly of cobbles laid in lime mortar and 

 pointed or faced with cement mortar. The method of 

 construction used by the Bear Valley Water Company is 

 as follows: 



$1.30 a barrel; ordinary labor, $2 per nine-hour day; 

 masons, $3.50 to $4 per eight-hour day. 



The method use by the Crafton Water Company 

 was very similar. The ditch was excavated with 

 scrapers and shovels. No form was used for lining; the 

 sides and bottom were put in by line, the cobbles being 

 placed to line and grade in lime mortar, the interstices 

 between cobbles being filled and chinked. The surface 

 was evened off by forcing in cement mortar with a 

 trowel, and a coating of this cement mortar about % 

 inch thick covered the sides and bottom. The rock lin- 

 ing was about 1 foot in thickness. This work was done 

 in 1893, thirteen years ago, and was limited to the in- 

 take canal (one mile long) of the Crafton Water Com- 

 pany. According to one of the former directors of the 

 company no repairs have been made during these thir- 

 teen years. The work is still in good condition. The 

 average cost of this class of lining would probably be 

 about 13 cents per square foot. While substantial and 

 satisfactory, a stronger and not much more costly is the 

 next class described. 



(To be Continued in March Issue.) 



