43 



canal and to the placing of a rock drain under the floor of the canal. It 

 was also necessary to rush the work and this probably increased the cost. 



The South Kelowna system has started during this summer to excavate 

 and line the upper part of their main canal which is in very difficult ground 

 on very rocky and steep hillside, in some places the excavation alone costing 

 over $3 a lineal foot. The canal was very inaccessible, requiring the con- 

 struction of expensive roads to deliver the material and move the mixers. 

 The forms were carried considerable distance around the bluff. This and 

 other difficulties as well as the high cost of cement, brought the cost very 

 high. Cement cost about $5.25 a barrel delivered at the mixer, and was 

 mixed with 4 parts of sand and 5 parts of crushed rock. The canal was 3 

 feet wide at the bottom, 3 feet 3 inches deep and 6 feet 3 inches wide at the 

 top. The lining 3 inches >thick /cost about $2.15< a linear footer; about 21 

 cents per square foot. 

 Cost of lining without forms. 



The main canal on the Gage Canal system near Riverside, California, 

 has a bottom width which varies from 5 to 10 ft. and a depth from 3^ to 

 4 feet and side slopes of 1 to 1. The contract cost for trimming the canal 

 and placing the lining of cement mortar % to 1 inch thick was from 3% 

 to 4 cents per square foot. This work, however, was done many years ago 

 when labor was cheaper. 



The Burbank Power and Water Company of Washington has recently 

 lined 4,100 feet of the main canal which has a bottom width of 6 feet 6 

 inches, a depth of 2y 2 feet and a top width of 14 feet. The lining is 2% 

 inches thick for the bottom and 3 inches thick for the sides. At the top 

 of the sides the lining extends horizontally for 6 inches to form a coping. 

 The concrete was mixed in the proportion of 1 part of cement to 2 of sand 

 and 4 of gravel. The lining was finished by painting with a thin mixture 

 of 1 part of cement to 1 of sand. The contract price was $12.50 a cubic 

 yard or about ll 1 /^ cents a square foot. 



The U. S. Reclamation Service has lined 6 miles of the Main South Side 

 Canal on the Boise Project in Idaho, with a concrete lining 4 inches thick. 

 The canal is 40 feet wide at the bottom, 8 feet deep and 64 feet wide at the 

 top. The concrete mixture was 1 part of cement to 3 of sand and 6 of 

 gravel. A finishing coat of cement mortar was floated over the concrete to 

 give it a smooth surface. The work was done at a cost of a little less than 

 10 cents a square foot excluding the cost of preparing the foundation. 



These and many other examples show that for either method of con- 

 struction and with average conditions and average prices, a concrete lining 

 3 inches thick should cost from 10 to 15 cents, including cost of backfilling 

 or trimming the ditch to prepare it for the concrete lining and all cost of 

 engineering, depreciation and interest on the equipment necessary for the 

 work. A concrete lining 2 inches thick should cost from 7 to 12 cents. 

 The lower cost in each case should be obtained with very favorable con- 

 ditions. 

 Economy of concrete linings. 



While concrete linings have many advantages, it is not an economical 

 proposition to line canals indiscriminately without considerng all the fac- 

 tors upon which a decision should be based. The problem resolves itself to 

 a comparison between the cost and the benefits derived. The factors which 

 must be considered are (1) cost of construction, (2) cost of maintenance 

 and operation, (3) damages due to waterlogging and alkali, and (4) value 

 of water loss. 



