154 



THE IRRIGATION AGE. 



on land twenty feet from water and heav- 

 ily irrigated with warm water on the top. 

 Eight acres averaged 115 bushels to the 

 acre, and most of it was over fourteen feet 

 high. I have seen very fine corn in the 

 same region and on the same kind of soil, 

 low along the river where the water was 

 but a foot from the top, but it would not 

 run over ninety bushels. On the whole, it 

 is pretty safe to say, do not irrigate in this 

 way for anything unless there is some 

 special economy in it, and then plant only 

 such things as you are sure will stand it. 



Where the head of water is great and 

 the feeding flume large enough, furrow 

 irrigation may become practical flooding, 

 as in the picture given in Chapter X of 

 bad furrow irrigation. If you had 180 

 streams of one miner's inch each, and 

 should run them for twenty-four hours on 

 ten acres, this would be one half of 360 

 twenty-four-hour inches, or about half the 

 whole allowance for the year under many 

 of the best water rights in Southern Cali- 

 fornia. This would equal about nine inches 

 in depth, or three-quarters of an acre foot. 

 Nothing but very coarse sand could take 

 such an amount of water as that, even if 

 distributed over the twenty-four hours 

 evenly in steady fine rain. The folly of 

 trying to put it on from a ditch must be 

 apparent. Yet that was about what the 

 irrigator was trying to do in the picture of 

 bad furrow work. It leaches out fertiliz- 

 ers, cuts the soil and is in every way bad. 

 When the soil is so coarse as to require 

 such large streams you are approaching 

 the point where it is best to flood. Noth- 

 ing but sandy or gravelly land will need 

 streams of an inch apiece, and nothing but 

 land nearly level will stand them. You 

 have, therefore, the conditions for flood- 

 ing, and had better do it directly than in- 

 directly. You can then save your fertil- 

 izers, avoid cutting and do better work. 



Where you can get a large head of 

 water for only a short run you are gen- 

 erally compelled to flood no matter how 

 well small streams might run upon the 

 soil. This is liable to be the case at 

 times on many ditches depending on the 

 flow of a stream and not supplemented 

 by reservoirs. If the amount of water 

 used is based on the average of the sum- 

 mer flow, as it should be instead of on 

 the minimum, on which no one can figure 

 and which should not be established as 

 the limit of the capabilities of any country, 



there will be times when a run of large 

 heads for a very short time may be the 

 only way of accommodating all consumers. 

 This is liable to happen at the driest and 

 hottest part of the season when vegeta- 

 tion is demanding the most water to 

 evaporate and will suffer the most if it 

 does not have it. And sometimes it wants 

 it furnished very quickly, too. In such 

 case you may have to take a hundred 

 inches of water for five acres and handle 

 it all in two hours or so. And you may 

 have to be on hand at three o'clock in the 

 morning to take your turn, and every 

 minute you lose is so much gone, for at 

 the precise minute it is cut off. Such 

 occasions are short, but you should figure 

 on them as possibilities. You should find 

 out such matters before buying or plant- 

 ing, and especially before deciding what 

 system to adopt. Sometimes it is easy to 

 change from flooding to furrows and vice 

 versa. But sometimes it is not. It will 

 depend very much on how you have pre- 

 pared the ground. 



PREPARATION FOR FLOODING. 



If land is to be flooded even more care 

 should be taken in preparing it than if it 

 is to be watered from furrows. The 

 depth of water in all the checks should 

 be as nearly the same as is consistent with 

 reasonable economy in grading. And it 

 will not do to economize too much in this. 

 In many cases it would ultimately pay to 

 terrace the land somewhat in very broad 

 steps, taking care to leave no jump off 

 places, but smoothing it down so that ma- 

 chines can run over it. If the checks are 

 not level then the water stands deeper in 

 one place than in another. For best results 

 the water should be rushed over the land 

 in as thin sheets as possible, and never 

 allowed to stand longer than requisite for 

 enough soaking. Otherwise uneven wet- 

 ting results and the lower part is puddled 

 too much, both bad whether cultivation is 

 to follow watering or whether the piece is 

 in something permanent, like alfalfa. 



If your land has a slope of twenty-five 

 feet to the mile, which looks almost level 

 on a large plain, checks one hundred feet 

 wide would have the water in the lower 

 side about six inches deeper than on the 

 upper side. If you increase the depth 

 so as to give enough to the upper side 

 you injure the lower, for the six inches it 

 already has are too much for almost any 



