OCR Text |
Show RESERVOIR FOR DRY FARMS For Gardening and Other Purpose! It .Is Well to Make Careful Study of Storage Places. A number of small dams, as well as bigger ones, constructed under the superintendence of engineers, have gone out this spring, and much water run to waste. When it comes to the case of damming up the ordinary ar-roya ar-roya or dry creek .that merely was a heavy flood when a large area has become be-come saturated beyond Its holding capacity, ca-pacity, it must be recognized that we are endeavoring to accomplish something some-thing very difficult, if not in some cases impossible, unless the dam can be made to act as an overflow weir in times of sudden flood or a point of diversion provided higher upT for the flood waters have and will again need the whole space across the draw tor their flow. Having in view, however, how-ever, the immense importance of a reservoir to the dry farm for gardening garden-ing and other purposes, it is worth while to make a careful study of all places where water can be stored and to see if the natural difficulties cannot can-not be overcome. Rock is, as a rule, scarce upon the plains and concrete is expensive, and its success largely dependent on the solidity of its base approaches and overflows from the dam, often necessitating long and expensive ex-pensive aprons which may become undermined and fail. In a dry country the soil Is so ab sorbent that it takes a large drainage drain-age area in normal years to prevent any flow and yet only yesterday I saw a gravelly soil become saturated on a side hill In forty-five minutes to the point of producing a turn off on land plowed eight inches deep and. the drainage area was only 150 feet in depth, or a little less. The ground had been left with some back furrows and there were from four to twelve inches deep where trees had been planted, soil taken for use in other places and so forth. Some" of the holes filled and overflowed. Some absorbed the water in accordance with the amount of the clay mixed with the gravel. Only a few of them absorbed all the water where the soil had been removed and it fell on straight gravel with the furrows around the lower part of the lots, the small space, 200 feet by 150 feet, managed man-aged to practically absorb all the rain and hail, but it couldn't hold any more than the inch and a half that fell; in fact did not take quite all of that. The reasons why land will take a cubic foot of water under irrigation irriga-tion and be soaked with an inch and a half of rain till a run off occurs need not be gone into here. The point is how are we going to inter-i inter-i cept some of this water for future use at a reasonable outlay. In the first place the dam must be made as solid as possible, not be piled up as straight as it will stand ready to wash and settle' so soon as stress Is put upon it and in the next place It Bhould be provided with a very ample am-ple flow pipe leading water far enough away from the foot of the dam so it will not cut back during the storm period. The lower end of the flow pipe should be led into a ditch, when possible, possi-ble, that. will distribute the water on higher ground rather than allow it to run to waste down the creek. The land will take this water when It allows al-lows the rain to run off, as may be seen under any Irrigation ditch; but the main point, bo far as the reservoir reser-voir Is concerned. Is to lead It to a point where it will not cut back. Where a diversion of the supply cannot can-not be accomplished above the dam in time of flood, it is sometimes possible pos-sible to lead a ditch down either side of a draw and carry off the water, filling the reservoir from spillways or allowing it to fill only bo much as It will from the more restricted drainage drain-age area. |