EUEAL ENGINEERING. 89 



less than 6 ft. should be left on either side of the canal and the spoil should 

 be banked up on one or both slides. ... It is considered good practice to give 

 open ditches a minimum bottom width of 4 ft., except in very stiff, homogeneous 

 clay, where it may be 3 ft." 



Lumber box and cement and clay tile drains are discussed under covered 

 drains. "The smaller-sized tile should have a fall of at least 1 ft. per 1,000 

 ft. and the larger sizes at least ^ ft. Tile having an inside diameter of less 

 than 4 In, should not be used, and even 4-in. tile should be used sparingly, 

 usually at the extremities of .small branches. Experience has .shown that the 

 use of tile less than 5 in. in diameter is not warranted by the comparative 

 results and cost. ... In deciding whether a large covered drain or an open 

 canal shall be employed It is necessary to calculate the original cost of each, 

 taking account of all auxiliary and protective devices required, and then to 

 add to each sum an amount large enough to give an annual return, at current 

 rates, sufficient to cover the cost of maintenance." It is stated that covered 

 drains should never be less than 5 ft. deep and that depths of from 6 to 8 ft. 

 are much more efficient. " In general. It may be said that the proper location 

 of a drain depends upon the surface and subsurface topography, the nature of 

 the soil, and the source of the damaging water." 



Other sections describe protective devices for open canals and covered drains 

 and typical problems encountered in the drainage of irrigated lands and their 

 treatment. 



In discussing the construction of drains it is stated that the most satisfactory 

 method of constructing open canals is by means of some efficient excavating 

 machine. In installing covered drains either hand labor or trenching ma- 

 chinery may be used. 



The final sections deal with maintenance, subsequent treatment of land, the 

 results and cost of drainage, and cooperative drainage. " The cost of draining 

 ordinary sized farms having an average soil that is neither so hard as to re- 

 quire picking nor so soft that extreme trenching difficulties will be encountered 

 will range from $10 per acre to $20 per acre, with the average between $14 and 

 $15 per acre. If hardpan be present or if the soil is so finely divided and so 

 wet as to be fluxible, the cost will run up to $50 per acre, and even more if 

 much sheeting is required. In a few special cases drainage of small tracts in 

 the midst of unreclaimed lands has cost between $75 and $100 per acre, but 

 these costs represent situations that would not be encountered in regular 

 operations." 



A land-drainage problem in Missouri, C. H. Milleb (Engin. Neics, 72 (1914), 

 No. 12, pp. 579-582, figs. 2). — This article describes the solution of an extensive 

 drainage problem, providing for the drainage of an area of 425,000 acres by 

 means of levees, drainage ditches, and river by-passes. 



Stream-gaging- stations and publications relating to water resources, 1885— 

 1913, Parts VI-X, compiled by B. D. Wood ( U. S. Oeol. Siirveij, Water-Supply 

 Paper SJ/O {1915), F, pp. XXin+63-82; O, pp. XXII+83-9f,; H, pp. XXI+95- 

 10); I, pp. XXIII+105-116; J, pp. XX 1+117-129). —Data similar to those re- 

 ported in the first five parts (E. S. R., 32, p. 381) are given for other sections, as 

 follows : Parts YI, Missouri River Basin ; VII, Lower Mississippi River Basin ; 

 VIII, Western Gulf of Mexico Drainage Basins ; IX, Colorado River Basin ; 

 and X, The Great Basin. 



Winter stream measurements in western Canada, P. M. Sauder (Engin. 

 News, 72 (1914). No. 19, pp. 920-924, figs. 10). — ^A description is given of stream 

 measurement work done by the irrigation branch of the Canadian Government 

 under particularly disadvantageous conditions in winter. 



