Foreword

The ability to understand and construct flow nets is an essential skill of a groundwater hydrologist. Although other books published by The Groundwater Project also discuss flow nets, the present book gives an in-depth treatment, in particular, how to graphically construct flow nets. Through this pencil-and-paper exercise, students can gain a deeper level of intuition and understanding of groundwater flow.

Many groundwater textbooks have been published in the past half century and nearly all of them draw attention to the importance of flow nets in groundwater investigations and each provides several pages about the manual method of constructing flow nets. In current professional practice, flow nets are produced quickly using readily available software after the user defines the boundary conditions and distribution of hydraulic conductivity. The challenge to those who are new to groundwater work is determining the boundary conditions and understanding the how the boundary conditions and hydraulic conductivities control the distribution of hydraulic head and flow lines. Therefore, it is important for aspiring groundwater professionals to develop an intuitive sense regarding the appearance of a flow net for a given system before generating a computer simulation of a flow net.

Intuition can be developed by creating flow nets using the “old-fashioned”, pencil-and-paper method of hand-drawing flow nets. This book explains that method and presents videos showing laboratory representations of groundwater systems in Hele-Shaw parallel plates and sand box models with dye revealing the flow lines. In addition, an online interactive software tool is provided so readers have an opportunity to enhance their intuition of flow systems by creating flow nets in groundwater systems with complicated hydraulic conductivity distributions.

Eileen Poeter initiated this book and reached out to Paul Hsieh to co-author it with her. The end result is a book on creating and understanding flow nets prepared by two globally recognized experts. The book was improved through a comprehensive peer review process. Consequently, the material in this book presents the type of groundwater knowledge that supports better groundwater management and protection.

John Cherry, The Groundwater Project Leader
Guelph, Ontario, Canada, July 2020