484 EXPERIMENT STATION BECOED. 



RURAL ENGINEERING. 



The effect of the width of the channel of approach on the flow of water 

 over weirs, W. F. Martin {ConieU Civ. Engin., 23' {1915), No. 5, pp. 180-190, 

 figs. 4).— "The object of this investigation was in part to supplement or con- 

 tinue the worli of Bazin, who had conducted experiments on sharp crested 

 weirs without end contractions, for the express purpose of determining the 

 effect on the coefficient of discharge of the height of weir above the bottom of 

 the channel of approach. 



" Four distinct series were run on sharp crested weirs, without lateral or 

 end contraction and having the same height of crest and same length of 

 channel of approach, but with widths 2.023 ft., 0.5165 ft., 0.2597 ft., and 0.1296 

 ft. . . . The heads ranged from the lowest or zero up to 1.5 ft. except for 

 the longest weir, in which case the maximum head was about 1 ft. 



" It was found that the coefficient of discharge varies with the width of the 

 channel of approach, the variation being very slow for the longer weirs and 

 quite rapid for the very short weirs. As might be expected, there is a decrease 

 in the coefficient of discharge. This effect probably ceases to be noticeable 

 when the length of weir is three or four times as great as the maximum head 

 on the weir." 



The relation of stream gaging to the science of hydraulics, C. H. Pierce 

 and R. W. Davenport {U. S.,Geol. Sintwij, Water-Supphj Paper 375-C {1915), 

 pp. 77-S4, fig. 1). — A brief discussion of the development of hydraulics with 

 reference to the measurement and computation of stream flow is given. 



Artificial control sections for river measurement stations, J. C. Hoyt ( Cor- 

 nell Civ. Engin., 23 {1915), No. 5, pp. 176-179, figs. 3).— The author states that 

 "the most successful control so far constructed consists of a low submerged 

 dam, which in many places may be made on a reef or bar of gravel or bowlders 

 by grouting with cement. In other places it may be necessary to excavate the 

 bed and build a concrete structure or to drive sheet piling across the section 

 nearly flush with the bottom. Such structures will tend to prevent scour and 

 at the same time so limit the channel that the natural current reduces the 

 probability of silting." 



Surface water supply of Pacific drainage basins in Washington and upper 

 Columbia River basin, 1912 {U. 8. Geol. Survey, Water-Supply Paper 332-A 

 {1915), pp. VI-{-282, pis. 2). — This report, prepared in cooperation with the 

 States of Montana, Idaho, and Washington, presents the results of measure- 

 ments of flow made on the Queniult River, Puget Sound, and upper Columbia 

 River drainage basins during 1912. 



Ground water in Paradise Valley, Arizona, O. E. Meinzeb and A. J. Ellis 

 (U. S. Geol. Survey, Water-Supply Paper 375-B {1915), pp. 51-75, pis. 3, figs. 

 9). — This report deals with the ground-water supplies of an area covering about 

 200 square miles, which lies between the Phoenix and McDowell ranges of 

 mountains and occupies a trough-like depression that has been partly filled by 

 unconsolidated rock debris washed from the mountains. 



" Paradise Valley is underlain by a deep deposit of detrital material, which 

 in its lower part is saturated with water. . . . The water table . . . slopes 

 southward at an average rate of about 5 ft. to the mile, which is much less 

 than the slope of the land surface. Along the Arizona canal the depth to the 

 water table is 50 ft., or slightly more; toward the north it increases as the 

 land surface rises until along the abandoned Verde canal it is nearly 300 ft." 

 The ground water of the valley is supplied from the run-off and underflow 

 of Cave Creek, the run-off from the mountain areas directly tributary to the 



