Review of Hydraulic Engineering of Dams by Willi H. Hager, Anton J. Schleiss, Robert M. Boes, and Michael Pfister

Dams are fundamental civil engineering structures used to supply water for human use, irrigation, hydropower, and flood control, among others. The design and the construction of a dam involves an interdisciplinary approach including mechanical, electrical, geotechnical, and hydraulic engineering. The book Hydraulic Engineering of Dams (HEoD) is a new title adding to the body of knowledge relating to the trip of water across a dam and its structures. The skeleton of the book is based on the former title Dam Hydraulics (Vischer and Hager 1998), which mainly presented hydraulic flow phenomena pertinent to dams, whereas HEoD largely expands the scope to applied civil engineering and design. Therefore, the current book HEoD is a new and fresh title. The presentation followed in HEoD is rather unique to other published works on the topic. It gives information of the flow phenomena starting from basic fluid mechanics considerations, provides design equations and/or computational methods, and presents detailed examples and/or the evaluation of the procedures using detailed laboratory observations to support the design methods. It renders the book useful for teaching, research, and practice. Portions of the material can be used by instructors for courses at both undergraduate and graduate levels, and the clarity of presentation also makes it a valuable reference for students.

Chapter 1 introduces the dams and their structures. Chapter 2 is dedicated to frontal overflows, e.g., weir flow, including a detailed analysis of the standard spillway crest as well as other important weir flow problems such as scale effects. Spatial crest overflows are considered in Chapter 3, where side channels, morning glory, labyrinth, and piano key weirs and siphons are treated. Chapter 4 is dedicated to the spillway chute, a topic where significant advances were made in the past decade. Developing boundary layers, uniform-aerated flows, chute aerators, shock and roll waves, and stepped chutes are fully considered. Dissipation structures are fundamental elements to connect a flow over the dam with the river, with the current techniques fully considered in Chapter 5. Hydraulic jumps are described in depth, using both fundamental fluid mechanics considerations and detailed laboratory observations, including recent results for the undular jump. Stilling basins, drop structures, and free falls are presented. The link between a dam and the tailwater using a ski jump is accounted for in Chapter 6, including details of the jet, flip bucket, and tailwater scour both in granular and rock plunge pools. River diversion during dam construction is adequately described in Chapter 7. Diversion tunnels, river constrictions, culverts, as well as pier and abutment scour are extensively discussed. Intakes and outlets are considered in Chapter 8. Intake hydraulics are described under both low and high submergence effects. Gate flow is considered in depth, including low level outlets. Reservoir sedimentation is included in Chapter 9, where sedimentation processes are described including field measurements. Sediment bypass tunnels, turbidity currents, and sedimentation control are also included. Chapter 10 treats impulse waves, as typically occur due to a landslide impacting a reservoir. Wave theories are presented, as well as an interesting section on two-dimensional (2D) wave generation and propagation. The run-up process is described, presenting the transformation of a solitary wave into overland flow. Overtopping over both rigid and erosional dams is considered based on detailed laboratory observations. The dam breach is presented in Chapter 11, where the breach development and propagation of waves into the tailwater are accounted for. Hydraulic topics involving structural or soil mechanics considerations are not within the scope of the book, including hydraulic failure modes and the corresponding risk analysis.

The book is carefully edited with high quality figures, including functional definition sketches and normalized graphs showing the relation of the various governing parameters of a phenomenon, and photographs highlighting the beauties of water flow over dams. Typesetting is also a welcomed result, surely acknowledged while using the material to apply the procedures. References in the book are fully updated, with many important results recently published in international scientific journals. Additional literature given at the end of each chapter is a valuable tool for those readers wishing to explore a specific topic. A collection of solved problems is not included; given the length of the book, this would not have been practical. The text is clearly written, making it possible to use isolated parts by the fast reader seeking to apply specific elements to their particular needs. HEoD also includes detailed subject and authors indices, which are important for a book of such an extension.

As a matter of taste, I missed the inclusion of flood routing in the book, possibly as an appendix, including gate maneuvers. For dams under operation, one of the daily hydraulic problems is the operation of gates during floods. Therefore, methods of flood routing and the use of gates to control a flood are, in my opinion, fundamental hydraulic computations for dams. However, it is certainly true that others consider these aspects as hydrological engineering, so that no definitive statement is possible. This is not a limitation of HEoD, because other references can be used (Castro-Orgaz and Hager 2019; Ayuso and Castro-Orgaz 2021). Further, Chapter 11 deals with dam breaches. It is typical in this field of research to use the nomenclature “dam breaches” for the gradual development of a breach in an erosional dam body, e.g., as typical for earth dams. However, for concrete dams the failure process is fast and frequently considered instantaneous. The resulting phenomenon is called a dam break, a particular case of the Riemann problem (Montes 1998; Castro-Orgaz and Hager 2019). The title for Chapter 11 may give the reader the impression that dam break flows are excluded, which is not the case; they are in fact dealt with, including an interesting analytical solution for the tip of a dam break wave propagating over dry terrain considering flow resistance.

In short, HEoD is a new book with a complete, updated, and fresh presentation of dam hydraulics and its application to civil engineering. I am delighted to recommend it warmly to the interested reader. This unique material will be of great interest for university professors, researchers, water authorities, practicing engineers, and any reader with a technical background on the topic simply fascinated by the beauties of water flow in the most amazing hydraulic structure used in civil engineering, the dam!