The presence of water on this planet is the essential feature that allowed life as we know it to come into existence. The circulation of water on the planet continues to control the life patterns of all organisms and is the foundation for individual and societal human health, as well as ecological health. Knowing how and where water circulates through the water cycle is the foundation on which wise water management is built.
The effects of human activity on geological processes of planet Earth are now so significant that a new subdivision of geologic time, the Anthropocene Epoch, has been proposed for formal adoption. Knowledge of natural processes has always been of great importance to human survival in prosperous and resilient cultures. Now human activity is altering these processes in unexpected ways, thus understanding these natural processes and human-originated effects on them is of crucial importance to developing knowledge for their sustainable management.
The United Nations World Water Development Report of 2016 (UNWWAP, 2016) projects that the world could face a 40% global water deficit by 2030. This staggering figure is projected to worsen with increasing global temperatures due to climate change, expanding urbanization and population growth. By 2025, two-thirds of the global population will live under water-stressed conditions. The Global Water Crisis is urgent and requires innovation to identify, prioritize and accelerate global solutions.
Groundwater must be included in the solution to the global water crisis because it makes up 99% of Earth’s liquid fresh water (Shiklomanov, 1993) and is vital for the sustenance of rivers, lakes, wetlands, and ecological systems. However, few people see groundwater because it is hidden beneath the land surface. To overcome this “hiddenness”, the reader is invited to think about Earth’s fresh water in a new way, to envision that all the surface water we see in rivers, lakes and wetlands is just the tip of the Earth’s vast fresh water reservoir; that is, just the “tip of the iceberg” with the hidden portion of the “iceberg” being liquid groundwater rather than ice.