DUTY AND MEASUREMENT OF WATER. 1 63 



between the head of the main canal and their respedlive 

 gates. This loss is a varying one, being so great on a 

 hot day that if each gate is set to take its quota with- 

 out shrinkage, the man at the end of the system seldom 

 has enough water to drink. The West Highlands 

 water company in San Bernardino county put in a 

 system of weirs which will completely avoid this diffi- 

 culty. Their main ditch is one mile in length, with 

 six lateral branches, each the same length. At the 

 head of the first lateral the ditch e^^pands into a large 

 cemented basin having two outlets, one opening into 

 the main, the other into the lateral. In each opening 

 is set an iron gate of ample width and hight, and hav- 

 ing a sliding door which may be opened sidewise to 

 any given width and fastened at that point. Both 

 gates are exadlly on a level. The weir at the head of 

 each succeeding lateral is an exac5l duplicate. Five 

 weirs suffice for the six branches, the fifth one serving 

 for two, being at the last point of the division. The 

 distribution of the water is so arranged that but one 

 consumer has water in a certain lateral at a time. 

 Under this arrangement the zanjero or ditch walker, 

 starting at the head of the main line with, say, six hun- 

 dred inches of water to be divided equally among the 

 six laterals, goes to the first weir and sets the gates in 

 the ratio of five for the main to one for the lateral, and 

 so on, the gates in the last weir being set equally open. 

 Measurements to ascertain the amount of water are 

 made on the open weir basis. Under this arrangement 

 it will be seen that any decrease and likewise any 

 increase in the flow is equitably divided among all 

 parties on the system. 



