Physical Hydrology, now in its third edition, is an established entity amongst the written works on hydrology. Providing thorough coverage from fundamental principles to more esoteric applications, this recent update incorporates evolutions in conceptual understanding of hydrological processes and their interactions over many scales. With the viewpoint of hydrological science as a foundation for engineering hydrology and water resources management, the book carves itself a comfortable niche amongst others of its kind.
Readers will find a well laid out book with a structure that is logical in its progression. The text is well written and to the point. Ten chapters under three parts, six appendices, and supplementary material in CD format, provide the necessary information for a good grounding in physical hydrology. The format is coherent throughout and aids readability, with main points highlighted in bars separate from the main text. Examples, detailed methods and derivations are presented in distinct boxes, whilst revision exercises are provided at the end of each chapter. Equations are consistent in presentation and symbology, but can be poorly defined. A list of symbols is sorely missed, as are lists of figures and tables. The CD provides some useful aids to the main text and exercises, along with a chapter on water resources management from a previous edition. A word of warning though; these are mostly reliant upon the Microsoft suite of software.
The book should achieve its purpose as an instructional text for upper-level undergraduates, graduate students, and experts alike. For the practising hydrologist the book provides a useful reference point. Required information is easy to find and concise. However, readers from other standpoints will likely have varied success. On the one hand, undergraduate students or those with less technical experience may find the book quite dense and difficult to learn from. The text is a little dry, can be equation heavy, and often lacks in supportive discussion. On the other hand, those of a more mathematical persuasion will find the going easier and be able to attain a deep understanding of the physical processes. Readers benefit from explanations of genuine field methods and data analysis following on from background theory. It is good to see some of these that practical hydrologists encounter on a day-to-day basis covered, such as different methods of geostatistical interpolation. The revision exercises at the end of each chapter help cement the main points, but are limited in scope. More targeted questions would improve the book as a teaching aid, especially around its motivational bases of engineering hydrology and water resources management. Defined case studies would further help bridge the gap between the classroom and what lies beyond.
The first chapter sets out the nuts and bolts and provides an admirable introduction to the science of hydrology. Terms are comprehensively and simply defined, covering, in addition to the basics, the conservation equations, stationarity and uncertainty. Chapter 2 broadens the reader’s view to the global scale and encapsulates the major features of the hydrological cycle. Climate and its change, water bodies and courses, the critical zone, vegetation and feedbacks are explored succinctly, and illuminated by observational evidence.
Remaining chapters present the principal components of physical hydrology in a mostly conventional manner, yet with some exceptions. It is interesting to see that the physical concepts underpinning precipitation, evapotranspiration and snowmelt are separated into a distinct chapter rather than being introduced with each process. This is also the case for principles of soil mechanics and groundwater flow, given a chapter separate from others on water movement in soils and groundwater. The reasons for this separation are hard to pin down, although it does help define the hard physics from environmental interactions. The topic of snow and snowmelt is also given its own chapter, possibly hinting at the authors’ US background and its relative importance there. Indeed, the book does come across as somewhat ethnocentric in its application of US authored references, examples, and colloquialisms such as ‘Baldy’s Law’.
Appendices add some insightful information and support. The sections on statistical concepts and stream gauging methods are very applicable and well worth perusing. It would, perhaps, be useful to update and reinsert Chapter 10 of the second edition from the CD to provide a concluding chapter and draw together some of the ideas presented in the book. It also seems reticent to append the subject of hydrological modelling rather than assign it to a full chapter, considering its contemporary importance within the science. However, these are minor gripes and the focus on physical processes within the book justifies such an arrangement.
For practising hydrologists, this is probably one of those books you will have on the shelf for reference. Others wishing to gain a sound foundation in the science of hydrology should consider it a definite option; though, take care when applying it to learning environments. The suitability of the book will depend on the readers’ technical ability, background and objectives. Nevertheless, persevere and this scientifically excellent book will provide you with a good conceptual understanding of fundamental hydrological processes.
Andrew House
Centre for Ecology and Hydrology, Wallingford, UK