TECHNICAL GRAPHICS
Preparing and studying diagrams of where our water is, where it is going to, and the relative quantities represented by each flow path, is one of the best ways of beginning to understand any hydrologic system. This diagram illustrating water supply and use in Jordan in about 1990 is a typical example. link not yet established)

For some more conventional, but still hugely informational, graphics, a great place to look is at UNEPs Vital Water site

Illustrating things on a smaller scale, but in a much more detailed way, are the fine graphics Gregg Eckhardt has put in his Edwards Aquifer site.