Review of “Engineering Hydrology: An Introduction to Processes, Analysis, and Modeling” by Sharad K. Jain and Vijay P. Singh

Some of the earliest traces of what we now know as hydrology perhaps started in the mid-1800s. Since then, hydrology has grown into a science in its own right, demanding the latest tools and algorithms for analysis and design. This book is an attempt to capture the various aspects of hydrology that engineers must contend with in hydrologic studies.

The 22 chapters in the book have been partitioned into five parts. Preliminary aspects form Part 1. Chapter 1 introduces hydrology with broad definitions and a brief historical perspective. The hydrologic cycle along with various components such as precipitation, evapotranspiration, infiltration, and surface and subsurface flows are described in Chapter 2, with emphasis on the different spatial and temporal scales involved in hydrologic studies with different components. Carbon and nitrogen cycles are introduced as well. Chapter 3 describes the water balance and how different components dominate it based on temporal and spatial scales. The concept of closing error in the water balance will be of relevance to readers.

Part 2 describes the various hydrologic components. Chapter 4 starts with precipitation as a driver of many hydrologic phenomena and describes cloud types and formations, methods for estimating rainfall, data processing, and disaggregation procedures, and contains a brief section on interception. Various traditional and emerging methods of quantifying evapotranspiration are covered in Chapter 5. Infiltration and soil moisture are the topics of Chapter 6, which includes basic definitions, development of the Richards equation for unsaturated flows, and popular infiltration models. Surface water is covered in Chapter 7 with discussion of catchment delineation, streamflow components, hydrograph development, runoff generation, and baseflow separation. Geologic formations, aquifer types, and hydraulic properties such as specific yield and retention, hydraulic conductivity, transmissivity, and storativity are described. Darcy’s Law and governing equations are discussed in Chapter 8, on groundwater. Readers are also exposed to well hydraulics and stream-aquifer interaction in this chapter.

Though not typically treated as a hydrologic component (i.e., part of the hydrologic cycle), water quality is the subject of Chapter 9, in Part 2, which introduces readers to the physical and chemical aspects of water quality, including biochemical oxygen demand, nitrification and denitrification, oxygenation, and nonpoint source pollution. This is in preparation for future chapters that draw on these concepts.

Part 3 is devoted to measurement techniques reflecting the rising importance and growing role of new sensors and sensing platforms in hydrologic practice. Chapter 10 addresses data observation networks driven by data needs, design steps, integration of precipitation and gaging networks, groundwater monitoring, and water quality networks. Readers will find the section on reference climate and water data networks to be relevant when embarking on hydrologic studies. Streamflow measurement techniques ranging from manual stage measurements to acoustic doppler current profilers, followed by stage-discharge relationships, are described in Chapter 11. Chapter 12 covers remote sensing and geographic information systems with introductory-level treatment of how these tools are shaping hydrologic data gathering and storage computations.

Part 4 is devoted to analysis and modeling in hydrology. Chapter 13 discusses rainfall-runoff transformations using the Soil Conservation Service (SCS) curve number method, the rational method, hydrograph estimation, and snowmelt modeling. The focus is on unit hydrograph theory in Chapter 14, which deals with instantaneous unit hydrographs, synthetic unit hydrographs (Snyder and SCS models), and conceptual unit hydrograph models, including linear reservoir representation, Nash and Dooge models, and the geomorphologic instantaneous unit hydrograph.

Flow and reservoir routing is the subject of Chapter 15. The Muskingum method and Saint-Venant’s equations and approximations are covered here, as are storage-routing methods for reservoirs such as the modified Puls method and the mass curve method.

Pollutant transport through advection, diffusion, and dispersion in streams, urban and agricultural watersheds, and subsurface flows is the subject of Chapter 16, which provides brief descriptions of numerical methods for specific applications. Chapter 17, on environmental flows, discusses the other aspect of environmental modeling where the concept of river health is introduced and methodologies for assessing environmental flows are presented.

Hydrologic design is the subject of Part 5. The basic statistical concepts of hydrologic data, the idea of return period, and the commonly used probability distributions and parameter estimation techniques are provided in Chapter 18. Chapter 19 discusses correlation, regression, and trend analysis. Hypothesis testing and significance levels are also elements of this chapter. Hydrologic modeling through lumped and distributed models is covered in Chapter 20. A distinction is drawn between conceptual and physical models. The challenges of equifinality and uncertainty when using optimization methods for parameter estimation in hydrologic models are highlighted here. Chapter 21 describes design storms through depth-duration-frequency analyses along with storm transposition and maximization. Design flood estimation using probable maximum flood, standard project flood, and frequency-based flood is also covered. Finally, Chapter 22 introduces the challenges posed by climate change, simulating climate change through global circulation or regional models, and methods of downscaling. It discusses adaptation and mitigation strategies in this context.

Overall, the authors offer a comprehensive treatise on engineering hydrology. History buffs will appreciate the reference to ancient civilizations and texts that attest to the role of water in society. While materials in Part 1 form the basis for an introductory course, subsequent chapters contain both introductory and advanced materials. An instructor wishing to adopt this book may pull together sections to offer coherent courses at the undergraduate or graduate level and determine the level of design content to include. Frequent examples and exercises make this book attractive as a textbook. The description of measurement techniques along with methods of data analysis and design should appeal to practitioners. The book holds appeal for a wide audience of hydrologists.