For centuries humans have been pumping aquifers but it wasn’t until 1935, when C.V. Theis at the United States Geological Survey (USGS) introduced the unsteady-state solution to the groundwater flow equation, that the effect of aquifer storage in confined aquifers was taken into account based on the physics of the system. This was the start of the modern era of assessment of aquifer exploitation and sustainability in which all of the potential sources of extracted groundwater are conceptualized for the aquifer water budget. However, surprisingly for many aquifers around the world where there is reliance on the extracted water, the water budget is not well understood, or is insufficiently quantified to serve for effective water management.
Depletion of aquifers is the norm in many countries. When an aquifer is pumped for a substantial period of time, such as years or decades, the answers to the questions: ‘Where is the pumped water coming from? and What is changing with time?’ often are not known. Hence, many aquifers enter into depletion without understanding of what is happening.
This book (Groundwater Resource Development: Effects and Sustainability) provides the concepts and principles that underpin understanding of aquifer depletion and sustainability. It explains the role that groundwater recharge plays in sustainability of groundwater exploitation. Although simple in theory, the role of groundwater recharge has remained elusive in the quest for science based water management.
The authors of this book, Lenny Konikow and John Bredehoeft (both emeritus of the USGS), have played key roles in the development and applications of the most advanced computer models for simulating aquifer exploitation and have long been leaders in the quest to integrate the appropriate models and concepts into sustainable groundwater development.
John Cherry, The Groundwater Project Leader
Guelph, Ontario, Canada, September 2020