170 



THE IRRIGATION AGE. 



Lining of Ditches and 



Reservoirs to Prevent 



Seepage Losses 



By PROF. B. A. ETCHEVERRY 



Berkeley, Cal. 



(Continued.) 



CEMENT MORTAR. 



This method is probably used more extensively in 

 southern California than all the other methods com- 

 bined. It has proven very efficient and its cost is small. 

 Examples of this class of lining are numerous all 



ment of the ground and because of the holes dug in the 

 banks by burrowing animals. 



2. Rapid growth of weeds, which decreased the 

 velocity of flow of the water, thus diminishing the car- 

 rying capacity. 



3. Large losses of water due to seepage. 



In 1890 it was decided to remedy these conditions 

 by making an experiment in canal lining by applying 

 a cement mortar plaster on the sides and bottoms of 

 the canals. The method used as described by Mr. Irving 

 and supplemented by information given by Mr. Mylne, 

 the present engineer of the company, is as "follows : " 



Method of Cutting and Preparing the Water Chan- 

 nel for the Lining (Pig. 6). The grade stakes were lo- 

 cated on the banks at a given distance from the top of 

 the sloping sides, usually 1 foot. These grade stakes 



6 a Method of lining canals used by Gage Canal Co. 



through the irrigated districts of southern California. 

 Some of the best types are in the vicinity of Riverside, 

 where the three irrigation companies the Gage Canal 

 Company, the Riverside Water Company, and the 

 Jurupa Company have used it extensively. The lining 

 usually consists of a cement mortar plaster, varying 

 from % to 1 inch in thickness. Various methods are 

 used in preparing the canal for the lining and in apply- 

 ing the lining. 



The Gage Canal Company began making im- 

 provements on its main canal in 1886; from 1886 to 

 1890 this was reconstructed, the total length being 20 

 miles. In 1890 the control of the Gage Canal Company 



were spaced at intervals of 20 feet. A level rod or cross- 

 section rod of sufficient length to reach from one bank 

 to the other was held at right angles to the ditch, with 

 one end on the grade stake and the corresponding stake 

 set on the other bank. The location of the bottom stakes 

 was obtained by measuring from this rod, by which 

 means they were placed in alignment and to grade every 

 20 feet. A line was stretched at the bottom between 

 the 20 feet grade stakes, and the bottom was then cut 

 to grade. Strips of iron, 1 inch wide and 14 inch thick, 

 and about equal in length to the length of the sloping 

 sides, were placed on the sides every 3 feet, extending 

 up and down the slope, the slope given them being the 



.,.?/ *-' 



6 b Gage canal in cut and in fill. 



passed to the Riverside Trust Company. The condi- 

 tions prevailing at that time are fully discussed by Mr. 

 Irving, the engineer of the company, in the report of 

 Irrigation Investigations for 1901 (part 2), prepared 

 by the Office of Experiment Stations. The conditions 

 were those usually encountered by other systems where 

 the canals are not lined, viz : 



1. Serious breaks in the canal, causing large 

 waste of water and inconvenience to irrigators. Large 

 fills were always in danger of breaking, because of settle- 



slope of the finished ditch. They were set in position 

 by the use of a specially constructed device as illustrated, 

 which gives the correct slope, the grade line giving the 

 proper position for the lower end of the iron rod. 



These iron strips were set every 3 feet along the 

 slopes. A sharp iron straight edge, a little over 3 feet 

 in length, was used to shave off the irregularities be- 

 tween them; or if below the alignment, the depression 

 was filled in and well tamped. Usually there were two 

 gangs of men; the rough finishers came first and re- 



