154 



NA TURE 



[June 13, 1901 



STORAGE RESERVOIRS. 



Rese>"voirs for Irrigation, Wa/er-Poiver, and Domestic 

 Water-Stipply. By James D. Schuyler, M.Am.Soc. 

 C.E. Pp. xviii+414. (New York: John Wiley and 

 Sons. London : Chapman and Hall, Ltd., 1901.) 



THE title-page of this book states that it also contains 

 " an account of various types of dams, and the 

 methods and plans of their construction ; together with 

 a discussion of the available water-supply for irrigation 

 in various sections of arid America ; the distribution, 

 application, and use of water ; the rainfall and run-off; 

 the evaporation from reservoirs ; and the effect of silt on 

 reservoirs." The book was, accordingly, designed to 

 embrace all the main questions relating to the construc- 

 tion of reservoirs, together with the distribution and use 

 of the water stored up ; but in reality the different 

 methods of construction of reservoir dams, descriptions 

 of numerous examples in the United States, and refer- 

 ences to the works required for several projected reservoirs 

 constitute the principal subjects dealt with. The most 

 remarkable feature, however, of the book is the abundance 

 of views of reservoir dams, reservoirs, and proposed sites 

 for reservoirs, comprising a large proportion of the one 

 hundred and eighty-three illustrations, which should 

 prove very attractive to the general public ; whilst the 

 plans and sections of dams and other contingent works, 

 maps of reservoirs and of proposed sites for reservoirs 

 with contour lines, and twenty-five folding plates, in an 

 appendix, of reservoir sites in California and the Lahontan 

 and .Arkansas River basins, and of the Sun River system 

 of reservoirs in Montana, will appeal mainly to engineers. 



The book is divided into only six chapters, treating re- 

 spectively of Rock-Fill Dams, Hydraulic-Fill Dams, 

 Masonry Dams, Earthen Dams, Natural Reservoirs, 

 and Projected Reservoirs, to which an appendix is added 

 containing particulars of reservoir surveys and designs in 

 California, Nevada, Colorado,Montana,Utah, New Mexico, 

 and .Arizona, and the cost of reservoir construction per 

 acre-foot in the United States and other countries. 



Rock-fill dams of a temporary character, formed of 

 timber cribs filled with stone, were originally used in 

 California for impounding water for mining purposes ; 

 and subsequently more serviceable and more watertight 

 dams were obtained by introducing some dry stone wall- 

 ing in front of a loose stone embankment, faced with two 

 or three thicknesses of planks. Since then the loose 

 stone embankment has been made more durable by facing 

 it with asphalt concrete, or Portland cement concrete, 

 or steel plates, laid on a sloping dry wall, or by introducing 

 a central core of steel plates, or by a facing of masonry 

 backed with earth, or by facing it with earth. Examples 

 of these various types of rock-fill dams are described in 

 the first chapter ; and the extent of irrigation effected by 

 means of the water stored up by these dams is indicated. 

 Naturally dams of these economical types, imposed some- 

 times by the inaccessibility of the site and the necessities 

 of the case, and occasionally very carelessly constructed, 

 have not been e.xempt from failures, their bursting having 

 been sometimes accompanied by disastrous results. 



In a few instances, reservoir dams have been formed 

 in the United States by directing a powerful jet of water 

 against the upper slopes of a valley, and thus causing the 

 NO. 1650, VOL. 64] 



materials scoured from the hillsides to be conveyed by the 

 water to the site of the dam proposed to be constructed 

 across the lower part of the river valley. Piy suitable 

 arrangements, the stream of water from the issuing jet 

 both conveys the materials by gravity to the required site, 

 depositing them along the lines of the two slopes which 

 are kept higher than the centre of the embankment, 

 and consolidates these materials in position, the larger 

 stones being dropped at the sides, and the finer materials 

 being carried towards the centre of the dam in drawing 

 off the water through standpipes. The best materials for 

 this hydraulic-fill construction are a mixture of soil, sand, 

 and gravel of various sizes ; and examples of dams in the 

 United States constructed successfully by this method 

 are given in the second chapter. Both rock-fill dams 

 and hydraulic-fill dams exhibit the peculiar resource 

 and boldness of American engineers ; though Canadian 

 engineers have resorted to the hydraulic system for the 

 formation of permanent embankments on the Canadian 

 Pacific Railway, in place of the temporary wooden trestle 

 viaducts provided at the outset for crossing valleys and 

 gorges rapidly and economically. 



The conditions of stability of masonry dams, involving 

 a solid rock foundation, and a well-established profile in 

 section varying with the height, have been so fully recog- 

 nised for many years past, and any considerable depar- 

 ture from them appears so certain to result in failure, as 

 illustrated by the history of the Bouzey dam in France, 

 which gave way in 1895, that there might seem to be 

 little scope for novelty in such constructions. Whereas, 

 however, in European practice the curvature of a masonry 

 dam in plan has generally been merely regarded as 

 conferring an additional element of stability on the dam, 

 American engineers have not hesitated to rely largely on 

 the arched form for the stability of some dams, which have 

 been given such slight sections that they could not pos- 

 sibly have resisted the water pressure unaided. This is 

 exemplified to some extent by the slender .Sweetwater dam, 

 90 feet high and only 46 feet thick at the base, and curved 

 to a radius of 222 feet ; and more especially the Bear 

 \'alley dam, which, though only 64 feet high, has been 

 made unprecedentedly slight with a thickness of only 8^ 

 feet 48 feet down from the top, where it rests on a masonry 

 base 13 feet thick, so that its section is absolutely at 

 j variance with correct principles, and it would long ago 

 I have been swept away had it not been curved up-stream 

 I with a radius of 335 feet. The Zola dam in France was 

 I constructed about 1843, twenty-three years before French 

 engineers inaugurated the correct profile for masonry 

 I dams by the completion of the Furens dam with ample 

 I stability in 1866, though retaining a maximum head of 

 i water of 164 feet : but unlike this latter dam, the Zola 

 dam owes its stability entirely to its arched form in plan 

 of 158 feet radius, coupled with the very short length of 

 23 feet at its base ; for the Zola dam, though 120 feet 

 high and 19 feet thick at the top, is only 49 feet thick at 

 its base, showing that no approximation to the correct 

 section had been reached at that period for what the 

 author calls "gravity dams," supporting the water pres- 

 sure by their weight alone. 



Several examples of masonry dams in the United 

 States are described and illustrated by views, sections. 



