8 SUGGESTIONS TO SETTLERS IN COLUMBIA EIVER VALLEY. 



HEAD DITCHES OR FLUMES. 



Where the soil is fine enough to prevent undue loss by seepage, 

 head ditches may be used from which to distribute the water into the 

 furrows, but where the soil is light and sand}^ and the subsoil is gravelly 

 or composed of coarse sand, flumes shovdd be used almost invariably. 

 They are more expensive in the beginning but, considering the saving 

 of water and the greater facility in handling it, are much cheaper in 

 the end. It is difficult to regulate properly the distribution of water 

 from ditches; on steep grades they cut deeply and on flat ones they 

 are constantly filling with silt and drifting sand. Practically all of 

 these difficulties are obviated by the use of flumes. Cedar is the 

 material best suited for their construction. Fir costs less but splits 

 badly and checks from exposure to the sun. Flumes should be kept 

 as low as possible to lessen the liability of blowing over and to prevent 

 the washing of the soil by the water dropping from a considerable 

 height into the furrows below. 



FURROWS. 



Where the soil is sandy and coarse, water moves downward from 

 the furrow by gravity much more rapidly than it does to the side 

 by capillarity. If the furrow^s are too far apart a great deal of water 

 will pass into the gravelly subsoil and be lost before the spaces 

 between the furrows become properly wet. By digging trenches at 

 right angles across the furrows at several points soon after irrigating, 

 some idea may be gained as to the relative rapidity with which 

 water penetrates the soil below and to each side of the irrigation 

 furrow. In this w^ay the irrigator can determine approximately the 

 distance apart the furrow^s should be for any particular soil. The aim 

 should be to have them close enough together for the spaces between 

 the furrows to become wet by the time the w^ater has penetrated to 

 the porous subsoil below. With soil 2 feet deep, water will probably 

 reach the subsoil before it will w^et the spaces between furrows 2 feet 

 apart. When this is the case they should be closer together, probably 

 a foot or 18 inches apart. 



Experience has shown, also, that the furrows should be much 

 shorter in the sandy soils of the Columbia River Valley than those 

 commonly used on finer, heavier soils. A square 10-acre tract 

 should have three or four lines of flumes crossing it, making the 

 furrows 220 feet long with three lines of flumes, or 165 feet long wath 

 four. In a coarse, sandy soil there is too much w^ater lost by seepage 

 near the flumes or head ditches when the furrow^s are long. 



SIZE OF STREAM TO USE. 



Water is supplied to the irrigating furrows from holes in the sides 

 of the flumes or from lath spouts in the banks of the head ditches. 



[Cir. 60] 



