586 EXPERIMENT STATION EECORD. 



upon them. This can be accomplished by adding to the main canals which now 

 traverse this territory — canals now surcharged with waters flowing out of Lake 

 Okeechobee." 



The suggested improvement includes 390 miles of canal draining 2,095 square 

 miles. 



Maps, tables, and charts showing in detail the data obtained by the investiga- 

 tion are also included. 



"Water conveyance and drainage works {Verslag Burgerl. Openb. Werken 

 Nederland^ Indie, 1911, pt. 4, A, pp. VIII +279, pis. 32).— This report describes 

 drainage works, including river improvements, and deals also with the con- 

 veyance of water in channels, both for drainage and irrigation. 



Preliminary estimating of canal excavation, L. M. Hammond {Engin. Rec, 

 11 {1915), No. 5, pp. 146, 147, figs. 6). — Three typical prism sections are worked 

 out in detail, formulas are derived, and tables and forms of notes are suggested 

 to expedite the work. 



Rock-fill dam with some extraordinary foundation problems, M. 0. Hindeb- 

 LiDER (Engin. News, 73 {1915), No. 14, pp. 660-664, flffs. 7).— The construction 

 of a rock-fill irrigation dam across a narrow gorge in southern Colorado is 

 described. As originally designed, the spillway was over an adjoining ridge 

 which on investigation proved to be of porous formation with the bedrock 

 sloping way from the dam. 



" For the purpose of intercepting the seepage from the reservoir through this 

 material overlying bedrock, a concrete diaphragm 2 ft. thick at the base and 

 1 ft. thick at the top was carried from bedrock upward to a point 10 ft. below 

 high-water line in the reservoir. . . . Above this concrete diaphragm the 

 trench was filled to the surface with equal parts of clay and sand mixed in a 

 concrete miser and run into the trench in the form of puddle." 



The spillway was transferred to the dam proper. 



Concrete chute drops water 130 feet from canal to reservoir, D. W. Cole 

 {Engin. Rec, 71 {1915), No. 15, pp. 456, 4-57, figs. 6).— A lined channel of the 

 Truckee-Carson project in Nevada has a cantilever upturn at the discharge end 

 and a long weir at the head to regulate the water level in the main canal within 

 the desired limits. A curious hydraulic phenomenon is the disappearance of the 

 back-water wave when the chute begins to operate normally. 



New type of gate for regulating adjacent water levels operates automati- 

 cally {Engin. Rec., 71 {1915), No. 10, pp. 304, 305, figs. ^).— A type of auto- 

 matically operated regulating gate which has been used in drainage canals by 

 the drainage department of the Province of Buenos Aires, Argentina, is de- 

 scribed and diagrammatically illustrated. 



" The design is based on the principle of momentary points of rotation, so 

 that for each rise in water level, dli, above a predetermined elevation, the gate 

 has a rotation d<i) in respect to a momentary point. Consequently, when the 

 gate is full open, that is, when the water level has risen a height h, it has 

 turned an angle (p and the point of rotation has traveled a distance s along an 

 arc. To prevent the gate from overtravel, and to insure the automatic closing, 

 a stopping arrangement limits the tilting of it." 



A modified type of this gate substitutes a roller on a piece of curved track 

 for the lower lever arm. 



Water supplies, S. and E. K. Rideal {London: Crosby Lockwood d Son, 1914, 

 pp. XII-{-214, pl^- ^4, fiffs. 10). — It is the purpose of this book to summarize the 

 science and practice of modern water supply and water purification, and it 

 deals primarily with the purification, filtration, and sterilization of water 

 supplies. 



