17G 



THE IRRIGATION AGE. 



Stubborn and refractory soils when drained are 

 frequently so changed in texture and mechanical struc- 

 ture that they become easily managed and respond to 

 cultivation with abundant crops. 



OPEN DRAINS. 



Underdrainage is that which directly affects the 

 soil and puts it in proper condition for plant produc- 

 tion. Provision for it assumes that sufficient natural 

 water courses or artificial channels exist to carry off the 

 water discharged by such underdrains as it may be 

 found wise to use. It is often the case, however, that 

 outlet channels must be provided before a system .of 

 underdrains which will operate successfully can be laid. 

 Natural streams are often insufficient and should be im- 

 proved in size and alignment. In fact, the location and 

 water-carrying capacity of general outlets as related to 

 the drainage area should receive particular attention in 

 the formation of drainage plans. When it is desired to 

 reclaim and improve large areas of level land, such 

 tracts must be cut up into sections or districts by large 

 open ditches in order that tile drains may be laid in 

 every part without necessitating the use of mains too 

 large and costly to be profitable. While these open 

 ditches are not desirable in themselves, since the land 

 they occupy can not be used for any other purpose, and 

 though they often divide the land into tracts of incon- 

 venient shape, yet they are necessary to every system 

 of underdrainage. They should be located with care, 

 following the course of natural drainage as nearly as 

 may be, with due regard to straight courses. 



When these outlet ditches are located on land be- 

 longing to one individual, he has merely to construct 

 them as he chooses and pay the cost of the work. But 

 in all large tracts in which a number of landowners 

 have interests, open ditches must be constructed by the 

 cooperation of all parties benefited. In several States 

 methods of doing this are provided for by statute. Out- 

 lets for the drainage of tracts varying from a few hun- 

 dred up to many thousand acres have been provided for 

 in this way, each owner within the district paying a 

 share of the expense of such work proportionate to the 

 benefit he derives. It is intended that when these main 

 channels have been made, each owner shall be provided 

 with an outlet for his drainage and that all subsequent 

 drainage of his own land shall be done at his own ex- 

 pense, without in any way infringing upon the rights 

 of others, while the general outlet will be controlled 

 by the proper officers as provided by law. 



The method of improving natural channels is often 

 suggested by the contour of the land and the conditions 

 surrounding the tract to be drained. Such channels 

 are usually crooked to a troublesome degree, and neces- 

 sitate the division of the fields into inconvenient shapes. 

 They are sometimes well defined by strong banks whrch 

 can be changed but slightly. In other instances, where 

 the channel winds through a tract of bottom land, it 

 can be greatly improved by cutting off the bends and 

 making the course as nearly straight as practicable. 

 Because natural ditches and streams are always crooked 

 it does not follow that artificial drainage channels 

 should be the same, especially where they extend 

 through tracts where only light grades can be obtained. 



Ditches upon rolling land may differ from those 

 on level land in several important particulars. Those 

 for the former, having a grade which gives a rapid flow, 

 may be comparatively small and shallow. The outlets 

 for tile-drains may, if necessary, discharge at shallow 



depths, since the lateral slope of the land is such that 

 the drains may be laid at the desired depth only a short 

 distance from their outlets. They may have narrow 

 bottoms, since the velocity of flow is sufficient to scour 

 and deepen them. In level land, however, it is often 

 necessary to provide for practically the entire drainage, 

 with but little assistance from the natural slope of the 

 land. The depth of ditches with grades of from 1 to 4 

 feet per mile should ordinarily be not less than 6 feet 

 and the bottom width not less than 4 feet. The side 

 slopes in loam or clay soils may be made at an angle 

 of 45, or what is called a slope of 1 to 1. Where the 

 soil is loose and sandy, the slope should be 2 feet hori- 

 zontal to 1 foot vertical, called a slope of 2 to 1. Ditches 

 excavated with teams and scrapers can not be profitably 

 made with slopes less than 2 to 1. 



CONSTRUCTION OF DITCHES. 



The well-known method of making ditches with a 

 plow and scoop scraper need not be described. Where 

 the earth is sufficiently dry to afford a footing for teams 

 and for the operation of the plow and scraper, it is an 

 economical method of making ditches. Where the earth 

 is dry, ditching contracts are sometimes let to farmers, 

 who do the work when farm labor is slack, at from 7 

 to 10 cents per cubic yard. Ordinarily contractors will 

 bid for such work at 10 to 14 cents under the conditions 

 usually encountered. A large part of open-ditch work 

 must be done when the ground is wet and in swamps 

 under conditions where it is impossible to use teams. 

 It is also necessary at times to make deep excavations, 

 where water is sure to be encountered and where the 

 earth is of such a character that it can not be handled 

 by teams and scrapers. 



There are machines which have been tried and 

 found adapted to the work where the ordinary scraper 

 can not be employed. For the making of small and 

 shallow ditches what is known as the capstan ditch 

 plow is used in some localities. It is an immense plow, 

 which makes a ditch by cutting and throwing the earth 

 from the center each way, its action being similar to 

 that of a common sod plow. There are wings which 

 push the earth thrown up 3 feet away from the edge of 

 the ditch, leaving it in a large, continuous ridge on each 

 side. The plow is pulled by two capstans, each of which 

 is turned by a team of horses. The capstans are an- 

 chored ahead and their winding drums are attached to 

 the plow by wire ropes. This machine makes a clean- 



FIG. 6. Section of capstan ditch. 



cut ditch 8 feet wide at the top, 1 foot wide at the bot- 

 tom, and ordinarily limited in depth to %y 2 f ee t- It is 

 used on Iowa and Minnesota prairie lands where it is 

 thought that ditches of this kind will serve the desired 

 purpose. Contract work is taken at about 60 cents a 

 rod for the completed ditch. In order to operate the 

 plow the earth should be saturated with water, so that 

 it may be cut easily and will slip from the wings readily. 

 A section of a finished ditch is illustrated in Fig. 6. 



In the construction of artificial channels for the 

 purpose of reclaiming large areas of level land there is 



