NATURE 



361 



THURSDAY, AUGUST 20, 1903. 



RIVER IMPROVEMENT. 

 The Improvement of Rivers. A Treatise on the 

 Methods Employed for Improving Streams for Open 

 Navigation, and for Navigation by means of Locks 

 and Dams. By B. F. Thomas and D. A. Watt, 

 U.S. Assistant Engineers, Members Am. Soc. C.E. 

 Pp. xiv + 356. (New York: John Wiley and Sons; 

 London: Chapman and Hall, Ltd., 1903.) Price 

 255. 6d. net. 



IN their preface the authors state that they know 

 of no recent book which treats of the improvement 

 of rivers except in a general way, possibly because they 

 seem not to be aware of the existence of a book, 

 "Tidal Rivers," published in 1893, and have not 

 apparently heard of the issue of a second edition in 

 1896, rewritten and enlarged, of " Rivers and Canals," 

 from the first edition of which, published in 1882, they 

 quote a long extract on the principles which should 

 govern the improvement of tidal rivers. Undoubtedly, 

 if the authors of these two books had confined their 

 attention to the rivers of the United Kingdom, there 

 would have been little matter in them properly applic- 

 able to American practice, owing to great differences 

 in the phvsical conditions of the two countries ; but 

 both these books range over a very wide field, and 

 deal with the improvement of rivers in various parts 

 of the world, including, of course, rivers in the United 

 States. Though, however, there is not such a com- 

 plete dearth of books describing the methods of im- 

 provement of rivers with extensive basins, as the 

 authors intimate in their preface, and on account of 

 which they express the hope that their book will supply 

 a much needed want, it is certain that the detailed 

 descriptions of American methods and experience re- 

 lating to the regulation and canalisation of large non- 

 tidal rivers, will be of great service, not merely to 

 those engaged in such works in the United States, but 

 also to all engineers who have to deal with large 

 problems of river improvement in countries containing 

 vast drainage-areas, as met w^ith in eastern Europe, 

 Asia, Africa, and Australia, as well as in North and 

 South America. 



The largest river-basin of the United Kingdom, that 

 of the Thames, with an area of only 5244 square miles, 

 owing to the comparatively restricted extent of the 

 British Isles, sinks into insignificance when compared 

 with the Mississippi, having the largest drainage-area 

 of the rivers of North America, amounting to 1,244,000 

 square miles, which, in its turn, is exceeded by two 

 river-basins in South America, namely, the La Plata 

 with a basin of 1,600,000 square miles, and the 

 Amazon with a basin of about 2,250,000 square miles, 

 the largest in the world. Accordingly, there is little 

 scope in the United Kingdom for regulation works, 

 and even for canalisation, which have enabled inland 

 navigation to be considerably improved and extended 

 along the large rivers of North America. On the 

 other hand, there have not been the same opportunities 

 in America for the great increase in depth of small 

 tidal rivers, by dredging and training works, affording 



NO. 1764, VOL. 68] 



access to seaports, as has been effected in Great Britain 

 in the Tyne, the Clyde, and the Tees, though access 

 for sea-going vessels has been extended from Quebec 

 to Montreal by dredging, in the St. Lawrence ; whilst 

 the most important works carried out in the United 

 States at the outlet of a river, are the parallel jetties 

 which were constructed several years ago in extension 

 of the South Pass of the tideless and deltaic Mississippi, 

 across the bar encumbering its mouth, in order to 

 concentrate the scour over the bar and thus deepen the 

 outlet channel. 



The authors deal very briefly with the improvement 

 of river outlets in a single chapter of only ten pages, 

 stating that this important subject would require a 

 volume ; and after quoting at full length the principles 

 laid down by an English engineer for the improvement 

 of tidal and non-tidal river outlets, and alluding to 

 the experiments with working models, carried out by 

 the same engineer, on the effects of training works 

 in tidal estuaries, they refer to the method of improve- 

 ment by jetties, and conclude with a short account of 

 the jetty works completed at the outlet of the South 

 Pass in 1879, and those authorised last year for obtain- 

 ing a navigable depth of 35 feet at the outlet of the 

 South- W^est Pass of the Mississippi. The book, 

 accordingly, really relates to the improvement of the 

 inland portions of large rivers for navigation by 

 regulation works or canalisation, in which the authors, 

 as assistant engineers in the Government Department 

 of the United States, which has control of all the 

 rivers, have wide practical experience, and for which 

 the book furnishes a very valuable guide. This large 

 quarto volume, with 349 pages of text, and illustrated 

 by numerous pages of drawings, diagrams, and photo- 

 graphic reproductions dispersed throughout the book, 

 and eighteen plates of detailed drawings at the end, 

 together with a few blocks in the text, deals with the 

 improvement of rivers in three distinct parts ; the 

 general characteristics of rivers and their surveys being 

 considered in the first part, the improvement of open 

 rivers in the second part, and the improvement of rivers 

 by canalisation in the third part. 



The first part is divided into five short chapters, 

 occupying only forty pages altogether, treating 

 respectively of introductory matters, the characteristics 

 of rivers, preliminary examinations and surveys, topo- 

 graphical surveys and levelling, and hydrographic 

 surveys. This part is mainly concerned with the pre- 

 liminary data which require to be obtained before 

 undertaking works of improvement, namely, the 

 physical features of the river, consisting of the amount 

 of the rainfall and the size of the river-basin, the fall 

 and nature of the river-bed, the sediment brought 

 down, shoals, bars, and changes in water-level ; next, 

 surveys of the course of the river; and, lastly, cross- 

 sections of the channel, and measurements of the dis- 

 charges over weirs and in the unimpeded channel. 



The second part is divided into seven chapters, and 

 covers ninety-one pages, dealing successively with the 

 " Removal of Bars and other Obstructions," 

 " Regularisation," *' Dykes and their Effects," "Pro- 

 tection of Banks," " Levees," " Storage Reservoirs," 

 and " Improvement of River Outlets." The first of 

 these chapters relates to the various devices attempted 



