Water and energy are fundamental components of our 21st century life, but they can no longer be considered separately. Just as producing energy consumes water, pumping, treating and distributing water requires energy. In other words, water is an energy issue; energy is a water issue. Called the water-energy nexus, this interrelationship is beginning to receive the attention it merits. This Arroyo aims to provide comprehensive and timely information to support the public discussion of this important topic.