Review of Sedimentation Engineering—Processes, Measurements, Modeling, and Practice (ASCE Manuals and Reports on Engineering Practice No. 110) by Marcelo H. Garcia: ASCE; 2008; 1132 pp. ISBN: 9780784408148. Price: $185.00/members $138.75.

Sedimentation engineering is a very important subject that deals with sedimentation processes such as erosion, entrainment, transport, deposition, and compaction of sediment induced by water, wind, gravity, and ice and affected by human activities. The original ASCE Manual 54 Sedimentation Engineering, edited by Vito A. Vanoni (1975) and the ASCE Task Committee for the Preparation of a Manual on Sedimentation assembled state-of-the-art information and knowledge on sedimentation engineering available at that time. Since then, the scientific and engineering understanding and knowledge of sedimentation processes have been greatly advanced and expanded. The recently published Manual 110, edited by Marcelo H. Garcia and his task team, updates selected topics in the original manual and presents recent advances and new topics in the field of sedimentation science and engineering as a complement to the original Manual 54. This update is timely and makes significant contributions to the literature.

This comprehensive volume consists of 23 chapters and 6 appendices. Among them, Chapters 2–4 broadly cover fundamentals of sediment transport mechanics, and a section of Chapter 19 briefly presents the mechanics of hyperconcentrated sediment flows. The original Manual 54 gives a good understanding of sedimentation processes and well defines the scope of sediment transport mechanics, whereas the new volume presents in considerable detail many recently developed theories and methods for non-cohesive sediment transport in sand-bedded streams (Chapter 2) and gravel-bedded streams (Chapter 3), as well as for cohesive sediment transport (Chapter 4). Chapter 2 also introduces turbidity currents, while Chapter 3 also presents the transport of multiple-sized (nonuniform) sediment mixtures, which has been extensively studied in the last three decades. Chapter 4 explains the effects of waves on cohesive sediment transport, but such effects on noncohesive sediment transport are omitted in this manual.

Chapter 5 reviews technologies for measuring bed-material properties and suspended and bed-load discharges, while Appendix D describes methods for estimating sediment discharges in streams using direct measurement data and empirical relations developed between hydraulic parameters and sediment transport potential. Several new types of samplers are introduced, as well as some traditional ones developed in the mid-twentiethcentury but modified recently. The measurement of bed load seems to be still a challenge because of the spatial and temporal variability associated with its transport. It is highly commendable that the authors rigorously point out the limitations and potential pitfalls associated with these sampling technologies and estimation methods.

Chapters 6 and 18 introduce the fundamental and engineering aspects of river geomorphology, respectively. Included are some basic concepts of fluvial geomorphology and river mechanics, approaches to understanding the present conditions and historical developments of river systems using available information and geologic and geomorphic knowledge, and their application to engineering design of channel rehabilitation projects and mitigation of geomorphic hazards.

Chapters 7, 8, 14–17, and 23 cover computational modeling of sedimentation processes. Chapter 14 describes one-dimensional models and Chapter 15 presents two- and three-dimensional models for simulating sediment transport in channels and the resulting vertical changes in bed elevation, while Chapters 7 and 8 address issues associated with the lateral stability of river channels and present models for assessing processes of bank erosion and channel meandering. Chapter 16 introduces modeling of turbulent flows in rivers, emphasizing the effects of sediment on turbulent flows. Chapter 17 describes soil erosion and transport processes in upland areas and presents models for simulating these watershed processes. Chapter 23 is specially associated with development and application of numerical models in assessing the impact of dam removal and decommission on upstream and downstream reaches. In addition, section 19.6 briefly presents the mathematical models of mudflows and debris flows.

Chapters 9–13, 19, and appendices A and B cover issues on selected sedimentation problems such as river restoration, bridge scour, reservoir sedimentation, ice effects, mud and debris flows, rock erosion, and riprap. Chapter 9 describes how to apply the principles and analysis methods of river mechanics to stream restoration, including data collection, channel design, sediment budget, stability assessment, habitat structures, and postconstruction monitoring. Chapter 10 presents methods for predicting the general scour, contraction scour, and local scour at bridge piers and abutments under river flows and tidal flows, while Chapter 11 describes prevention and countermeasures such as riprap and gabions for bridge scour. Chapter 12 illustrates reservoir sedimentation processes and the potential impact of dam removal on river systems and introduces sustainable use and management strategies pertinent to dams and reservoirs. Chapter 13 describes the cycle of ice formation and breakup, and the effects of ice on flow, sediment transport, and channel morphology in ice-covered streams. Chapter 19 describes hazards due to hyperconcentrated flows such as mudflows and debris flows caused by volcano eruptions, landslides, and strong storms, as well as approaches for mitigating such hazards. Appendix A summarizes methodologies used to determine the potential rock scour downstream of overtopping dams, spillways, and other in-stream structures. Appendix B specifically deals with design of riprap for river bank and bed protection, focusing on determination of stone size and other factors satisfying the geotechnical and environmental requirements.

Chapter 20 greatly updates the original Manual 54 regarding changes in American sedimentation law since the 1970s due to the evolution of sedimentation engineering concepts and practice. This chapter introduces important legal issues such as key trend-setting court decisions, public liability, sovereign immunity, tort and takings laws, “act of God” defenses, upstream versus downstream, and use of forensic geology, as well as recent trends and future directions in American sedimentation law.

Chapters 21 and 22 consider environmental issues related to contaminated sediments. Chapter 21 describes the general processes that affect the fate and transport characteristics of contaminants in bed sediments, including sorption/desorption, chemical/biological reactions, diffusion, advection, bioturbation, and sediment deposition/resuspension. This chapter also introduces common approaches such as capping and dredging for remediating or managing the related risks. Chapter 22 illustrates the mass transfer mechanism at the water-sediment interface and presents a method to estimate sediment oxygen demand in rivers, lakes, and estuaries.

The readers may recognize that compared with computational modeling, physical (scale) modeling is not introduced in detail in this manual; only appendix C briefly describes the key aspects for scaling sediment transport between a physical model and its prototype. This may be due to less and less use of scale modeling in sedimentation engineering in the United States in recent decades because it is usually very expensive. Other topics missed or explained in less detail in this manual include sediment transport by wind, in pipes, and in coastal waters, as well as channel erosion downstream of dams. Even so, the readers will find a substantial digest of information covered in this manual on sedimentation engineering mostly related to rivers and streams.

In summary, the Sedimentation Engineering Manual 110, along with its progenitor Manual 54, is a valuable reference on sedimentation engineering and management. It fills the sorely needed gap in this field. Both volumes will be beneficial to hydrologists, geomorphologists, sedimentologists, land-use planners, soil conservation specialists, and environmental, hydraulic, and agricultural engineers. Dr. Garcia and all contributors are congratulated on finishing this tremendous work.