Rainfall-Runoff Modelling - The Primer
By Keith J. Beven: Published by John Wiley & Sons Ltd, Baffins Lane, Chichester, West Sussex PO19 1UD, UK: 2000: ISBN 0-417-98533-8: 250 ´ 172mm: xi + 360pp: Hardback: £39.95.
The rainfall-runoff relationship is one of cause and effect. It rains and sooner or later the flow of streams and rivers will increase - but it is not quite that simple. Runoff is the total quantity of water flowing in streams and rivers. It includes not only the waters that travel over the land surface to reach the stream but also interflow (that water which infiltrates the soil surface and flows toward the stream channel above the main groundwater level) and baseflow, which is the groundwater discharge into the stream. The total runoff is equal to the total precipitation less the losses caused by evapotranspiration (loss to the atmosphere from soil surfaces and plant leaves).
The routes that rainfall water takes to get to the stream are varied and complex and, as Keith Beven points out in the first sentence of the preface, occur mainly beneath the ground surface. (He is the Professor of Hydrology and Fluid Dynamics at the University of Lancaster and has been submerged in hydrological modelling for more than 20 years). These sub-surface flow rates depend on very many variables that include the properties of the soil and rocks through which the water moves, how much rain fell, its intensity, the length of time since the previous rain, how wet the ground was before the rain stated and many more. It is no wonder that computer models are required to investigate these relationships. Understanding the rainfall-runoff relationship lies at the heart of hydrology and is required in water resources planning, flood prediction and protection, calculating the available dilution for contaminants and abstraction licensing and other practical applications of the hydrological sciences.
The author divides the book into ten chapters with two appendixes etc. The first chapter discusses the runoff processes and the processes involved in modelling followed by a brief history of the development of the modelling process in Chapter 2. Chapter 3 looks at the available data and makes the important point that the data are generally constrained by being point data and may not be error free. The modelling process must therefore, start with assessing the reliability of the available data. The chapter includes a range of other related data types and the use of GIS systems.
Chapter 4 considers models for the rainfall-runoff process that are directly derived from data without any explicit consideration of the processes involved. Consideration of the processes is discussed in the following two chapters. Chapter 7 is concerned with identifying the limits of the modelling process and the level of uncertainty in predictions based on them. Chapters 8 and 9 deal with the specific modelling applications of flood prediction and the effects of changes in land use and climate change on river flows. Keith Beven uses the final chapter to highlight difficulties in choosing the appropriate model and the difficulties associated with the uncertainties involved in modelling.
There are many features that make this book reader-friendly and the graduate and undergraduate hydrology students and professional hydrologists that will form the bulk of its readership will find it of great value. It contains more than 30 pages of references, five pages of index and eight pages of a glossary of terms. The book is illustrated by a large number of good quality line drawings and the author explains concepts in detail outside the main body of the text with great effect, by using a total of 21 boxes. Another useful inclusion is a summary of the main points discussed as provided at the end each chapter. Keith Beven has also created a special Web site, from which demonstration software can be downloaded, thereby greatly enhancing the learning value of the book. The site, which also includes a contents list for the book and an extract from the preface, is part of the author's Web pages at the University of Lancaster.
A primer is usually taken to be an elementary textbook, which is far from the case here and the non-specialist will get little from this book. However, as a starting point for studying and understanding rainfall-runoff modelling it is excellent. It is a comprehensive guide to rainfall-runoff models and modelling and I have no doubt that undergraduate and graduate students of hydrology for whom it is intended will gain a great deal from it, together with professional hydrologists who will find it of practical use.
This review appeared in the Journal of the Chartered Institution of Water and Environmental Management 2002, Volume 16, No 1, page 76.
Copyright © CIWEM 2002