488 EXPERIMENT STATTOlSr EECOED. 



impi-ovements, a complete draiuage survey of the district should be made and 

 a plau for the improvement be devised." Suggestions for making such a survey 

 and forming a drainage organization are given, as well as available data 

 regarding the rainfall of the region. 



The drainage situation in the lower Rio Grande Valley, Texas, L. L. 

 HiDiNGER {U. 8. Dept. Agr., Office Expt. Stas. Circ. 103, pp. 36, figs. 2, map 1). — 

 This report on the lower Rio Grande Valley, which when first settled gave 

 promise of large crops but markedly deteriorated after the first year or two of 

 cultivation because of seepage and the rise of alkali, discusses the soils, crops, 

 rainfall, alkali in the region, the movement of water and alkali in soils, the 

 allowable salt content of irrigation water, the rise of ground water in soils, 

 and methods of reclaiming soils. A plan for the drainage of a single planta- 

 tion is included. 



The general conclusions drawn as to the situation are as follows : 



" There is not an excessive amount of alkali in the most of the lower Rio 

 Grande Valley soils if it is kept distributed, but if allowed to become con- 

 centrated by seepage and evaporation there is suificient in nearly all of the 

 soils to prevent plant growth. . . . 



" The Rio Grande water is a good irrigation water. Any large amount of 

 alkali concentrated by its use will necessarily come from the soil. 



" It is very probable that in time the soils of the lower Rio Grande Valley 

 will fill up with ground water near enough to the surface to cause the alkali 

 to concentrate in harmful quantities, and that extensive drainage works will 

 be required. 



" In general, the drainage of the lower Rio Grande Valley lands can best be 

 accomplished by parallel lines of tile with or nearly with the slope, together 

 with an intercepting ditch along the upper side of the affected tract if the water 

 comes from a canal or higher lying irrigated lands. Where the seep spot is 

 small and a gravity outlet is not available it will be necessary to pump the 

 drainage water. This method will probably be necessary until enough land 

 has been swamped to force the construction of expensive outlet ditches. These 

 outlet ditches will be necessary after a time and should be constructed as soon 

 as districts can be organized." 



The selection and installation of machinery for small pumping plants, 

 W. B. Gregory {U. 8. Dcpt. Agr., Office Expt. 8ias. Circ. 101, pp. JfO, figs. 22).— 

 This circular, continuing work previously noted (E. S. R., 20, p. 88.5), is in- 

 tended primarily for persons who intend to install plants too small to warrant 

 the employment of a consulting engineer. It presents and summarizes data 

 as to the various types of pumps used for the purpose, dynamic head or " head 

 on pump," losses in pump installations, foundations for pumps, cost of centrif- 

 ugal pumps, types of engines, points to consider in choosing an engine, founda- 

 tions for engines, types of boilers, setting for boilers, boiler fittings, and 

 heaters. The data on many of these points are presented both in tables and 

 graphically. 



Delivery of water to irrigators, F. Adams {XJ. 8. Dept. Agr., Office Expt. 

 ^tas. Bill. 220, pp. 99, figs. 9). — In this bulletin are described the systems 

 adopted for distributing water to irrigators on about 50 irrigation systems in 

 California, Colorado, Wyoming, Montana, Utah, Idaho. Washington, Oregon, 

 Nevada, Arizona, and New Mexico. Each system is discussed individually and 

 a summary follows which deals with plans of deliA^ery, delivery force, rules and 

 regulations, records and forms used, suggested water charges, cost of water 

 delivei'y, lateral organizations, and the measurement of water. 



Of the 3 general plans of water delivery, that of continuous flow is deemed 

 unsatisfactory under ordinary conditions; that of rotation is found the most 



