3R40. River Mechanics. - PY Julien (Dept of Civ Eng, Colorado State Univ, Ft Collins, CO 80523). Cambridge UP, Cambridge, UK. 2002. 434 pp. ISBN 0-521-56284-8. $120.00.
Reviewed by J Tuzson (1220 Maple Ave, Evanston IL 60202).
The author approaches his difficult task by starting each chapter with the fluid mechanic and sediment particle dynamic fundamentals, which serve to define the key variables. However, these theoretical equations cannot be used to predict the flood-wave propagation, river bed changes and needs of navigation, which are the engineering objectives, primarily because the enormous volume of topological and other input data are not available and would anyway exceed the capacity of the available computer. Empirical equations are used, which consist of products of the variables with empirical exponents. To quantify these exponents, many valuable log-log plots are presented with clouds of experimental data points, which, however, scatter by a factor of two or sometimes much more. These correlations validate the approaches and provide a measure of their accuracy. But for actual, numerical predictions, it would be necessary to use data taken from the specific river that is to be studied, to determine the particular empirical coefficients applicable to the case. Available river databases are mentioned in Chapter 7. Finally small-scale river models offer the ultimate approach, as demonstrated in Chapter 10. Numerous case studies illustrate these techniques.
A brief historical introduction is followed by chapters on physical fundamentals, watershed calculations, steady and unsteady water flow, and sediment transport calculations. More qualitative and descriptive chapters follow, on riverbed changes by erosion and deposition and on practical measures to control them. The chapter on river engineering also includes flood control, canals, dams, dredging, and matters of barge traffic in great detail. These later chapters contain several interesting and instructive case studies. Separate chapters discuss small-scale model building and computer programs for flow and sediment transport calculations. The concluding chapter is devoted to surface waves and ocean tides in estuaries, subjects which certainly belongs in such a book.
The author’s expertise in sediment transport becomes evident from the brief chapters on the subject, obviously summarized from his numerous publications. Many pleasing illustrations, 340 references, and an index of 850 words help define such words as isohyetal, hypsometric, hyetograph, headcut, nickpoint, point bar, thalweg, washload, tieback, hardpoint, and groyne.
A dozen exercises and problems in each chapter make River Mechanics suitable as a textbook. However, the extensive subject matter would be difficult to cover in one semester, as suggested by the author. Indeed, the book contains ample information to make it a valuable reference work for scientists and practicing engineers also.
