a 



THE IRRIGATION AQB. 



made of all lengths from a few hundred feet to nearly 

 half a mile, though a quarter of a mile is nearer the 

 extreme. They vary in width from about sixteen feet 

 to twenty-five or more. I have some fifty feet wide that 

 work fairly well, but they are only three hundred feet 

 long. When wide it is most too difficult to get them 

 level on the bottom, that is level laterally so as to pre- 

 vent the water from sliding off to one side or running 

 in a dish down the center. Twenty feet is a better 

 width for alfalfa, while for melons and other garden 

 stuff I find ten wide enough. 



It is a mistake to make them too long, as it takes 

 too long to get water enough to the lower end and 

 keep it there long enough. Too much of the time 

 water is wasting by soaking in at the upper end after 

 it has soaked enough. Considerable must also run off 

 at the lower end so as to insure wetting it well. It is 

 better to have them shorter, collect the waste water in 

 another cross ditch and run it in a new set of lands. 

 Checks must be prepared to take the final waste or 

 some ground will be left too dry. Six hundred feet is 

 about the limit of efficiency on most soils unless there 

 is plenty of water to waste. The slope should be six 

 inches in a hundred feet to insure good running, and a 

 foot is better yet. When vegetation is heavy, still more 

 is better, but care must be taken in all cases about the 

 soil cutting when the ground is first planted. 



The levees for these lands do not have to be so 

 large as for flooding in checks. But when ground is 

 well covered with vegetation it makes great resistance 

 to the passage of water. The levees should be large 

 enough to force the water in spite of all resistance and 

 so strong that one cannot break and let the water into 

 the next one. If it does you may have a dry strip be- 

 low and have to haul in earth with a wagon to make 

 repairs. 



Neither do the gates have to be made with the same 

 care as for checks because the lands are so narrow 

 that large heads of water are not used, that is. large 

 compared with those generally used in checks. It is not 

 difficult to set several lands with the inlets about on a 

 level so that one cross gate in the ditch will supply 

 them all at once. Sometimes thev are set so that the 

 water does not enter until raised by the cross gate. 

 Then when it is opened to feed the next lot of lands the 

 water falls as it flows on so that the first lot of inlets 

 do not have to be closed at all and need no gates. 

 Sometimes it is best to start at the lower end and 

 work backward, closing cross gates instead of opening 

 them. And often vou can work both wavs. one way at 

 each irrigation. It will all depend on the li.v of the 

 land and the amoiint of water vou are running. If 

 you have a good slope the wav the lands run, with the 

 ground nearlv level on a liri" at a right angle to it, 

 vou cnn do it almost as vou please if the lands are not 

 so long or so wide as to take too much water. 



One feature of this method is that you can hardly 

 get the water too deep a groat advantage where vou 

 have to flood in gardening. "NTor do vou have to watch 

 it verv closelv ns it can do no harm except to waste 

 at the lower end. The levees are not liable to be broken 

 nv waves a in checks, nor can gophers make much of 

 a home in them a in larger ones. You have also a per- 

 fect clearance with a certaintv of no stagnant water if 

 thpv are Inid out on uniform slope. This means no 

 scalding of alfalfa or other vegetation unless you make 



a special effort to insure it. It takes some care, how- 

 ever, to keep a uniform flow in several lands. If not 

 you have to leave some running after the others are 

 shut off and this may require gates that might other- 

 wise be dispensed with. Careful grading of the slope 

 is more important than in checks. The water is flow- 

 ing, and flowing in a thin sheet, so that if a spot is 

 too high it will collect rubbish and split the stream, 

 often leaving a dry spot. And if a spot is too low it 

 may, after being well soaked, hold water long enough to 

 injure something the same as in a check with water 

 too deep. The surest way is to have the levees high 

 enough to force the water, and water enough to be 

 forced, and then collect the waste below and use it 

 over again. Another advantage of this method is where 

 you have short heads of water, or cannot run them a 

 long time, you can cover more ground than you can 

 with checks that are as cheaply made. But unless the 

 ground has a long and easy slope, needing very little 

 grading to make it uniform, with fall enough to in- 

 sure a fast run of water against a heavy stand of vegeta- 

 tion .lands will not be as cheap or efficient as small 

 checks might be. 



To flood or not to flood is therefore the important 

 question at first. And on its proper determination will 

 depend much of your success as well as comfort in your 

 work. With the right system selected and properly laid 

 out you should spend much of your time in the ham- 

 mock. Otherwise you may be hopping about all day 

 with a shovel wondering why there is so much work 

 for so small an area. In considering this question the 

 two systems, standing water and running water, will 

 be treated together as they differ only in the ways 

 above mentioned. To the following principles you will 

 find hardly an exception. Apparent exceptions are in 

 the wrong application of the principle. 



First. For handling large heads of water on a 

 large area flooding is the cheapest method, if slope 

 is not too great. 



Second. Where soil is so porous that water runs 

 in small furrows sinks in too fast, or sinks directly 

 downward instead of soaking sideways, flooding is gen- 

 erally the only way to insure quick and uniform wet- 

 ting. 



Third. Where soil is so tight that soaking from 

 furrows is too slow flooding must generally be used, 

 but with great care because on such land drainage is 

 probably bad. 



Fourth. Where your water supply is limited to a 

 short run of a big head flooding is often the only way 

 you can get it over the ground within the time limited. 



Fifth. Whore the slope is so light that water will 

 not run fast enough in furrows flooding in large heads 

 is often essential to quick work. 



Sixth. Where you have to take your turn at the 

 water in the night you can often arrange things so that 

 one check will feed another and pass on while you are 

 in bed. But if vour crops are very valuable, and espe- 

 cially if water is scarce, you had better stay up and 

 take care of it under anv system. If you have to go on 

 a night run this time the ditch tender will put you on 

 for a day run the next time if possible. Where the run 

 lasts much more than a day vou can generally arrange 

 furrows to run all night without watching. Such is 

 the case now in about all the orange orchards in South- 

 ern California, where the run is rarelv less than three 



