Preface

Chapter 8 **Study of Unsaturated Soils by Coupled Numerical Analyses of**

Norma Patricia López-Acosta and José Alfredo Mendoza-Promotor

**Water Flow-Slope Stability 163**

**VI** Contents

Groundwater is one of the most precious resources provided by nature for the benefit of humanity. Even though it forms only small portion of the fresh water available on this globe, yet its importance and contribution in the human survival on this planet cannot be fully expounded.

Groundwater is an important part of the hydrological cycle between the processes of perco‐ lation (entry into the ground) and extraction (natural or forced exit from the ground). The movement, transportation, geo-biochemical actions and reactions and behavior inside the ground are most fascinating for engineers, researchers, hydrologists, agriculturists, industri‐ alists and general consumers. Aquifer maintenance and management, aquifer conservation and aquifer resource balance between discharge and recharge are the areas for study to avoid and mitigate conflicts among the transboundary stakeholders. Positive contribution by engineers and scientists can not only add towards the development of this resource but also help in just and equitable utilization of it by all.

Whereas the fast pace development of built-up area and communication and habitation in‐ frastructure has grossly reduced the infiltration, percolation and aquifer recharge, on the other hand the extraction has increased manifold. There is thus a dire need to check the de‐ pletion rate and work for conservation and enhancement of this precious resource. These aspects can form the goals for future research and investment by all nations of the world. Numerical and computer modelling of groundwater movement and contaminant transport may help identify the gray areas and also suggest solutions in concrete terms.

This book contains eight chapters, which have been grouped into two sections. Section I in‐ cludes chapters 1–4, which are related to resource development and aquifer management, focusing on the issues of water quantity, water quality, contaminant transport, etc. Section II includes chapters 5–8, which are related to the study and use of numerical simulations and computer modelling in analysis of groundwater flows. Chapters in each section have been grouped having the common focus and theme, thus synergizing the thought and knowl‐ edge. Within Section I, the first chapter provides an appraisal of groundwater flow and aquifer recharge in sub-Himalayan watershed. Chapter 2 gives an insight into the ground‐ water recharge trends and variability in Taiwan. Chapter 3 describes the flow through mul‐ tiple well point systems, and the final chapter in this section analyses the mobility of inorganic contaminants in mining impacted groundwater. All the four chapters in Section II provide an insight into some particular aspect of numerical modeling and simulation of groundwater flow. Chapter 5 focuses on various methods available for numerical analysis of flow through earth structure. Chapter 6 homes around karst aquifers and conduits and transport of water and solute within these. The next chapter encompasses the study of trans‐

port processes in vadose zone, whereas the final chapter is about water mobility and slope stability coupled numerical analysis within unsaturated soils.

This book has a broad-based wider scope due to elaborate coverage on many aspects of groundwater. The book is aimed to serve the needs of graduate students and professionals in groundwater engineering, water resource engineering, hydrogeology, water resource management, environmental sciences and geotechnical engineering.

Many persons contributed directly or indirectly towards the completion of this book project, which is thankfully acknowledged. It would not have been possible to complete this book without the professional contributions of the eminent authors whose names appear with each chapter title; the groundwater scientists and engineers the world over. Guidance, ad‐ vice and blessings of my professional colleagues and friends and unwavering support of my family members (wife Sultana, daughters Humaira and Sumayyah, and son Hammaad) are fully acknowledged; therefore, I dedicate this book to my family and colleagues in the pro‐ fession of handling groundwater. Dr. Jamil Ahmad, Vice Chancellor, faculty and staff of Abasyn University, Islamabad, need a mention for providing me working atmosphere, space, time and resources at university's cost. Last but not least I would like to thank Ms. Andrea Koric, the publishing process manager whose patience, guidance and relentless ef‐ forts made us all follow and obey the laid out time lines.

> **Dr. Muhammad Salik Javaid** Abasyn University, Islamabad, Pakistan
