This section focuses on hydrology. It goes without saying how important water is to all life on the planet. We simply cannot survive without it. Water is what sets the Earth apart from the other planets in our solar system. While the oceans cover roughly 74% of the Earth’s surface and are the driving force behind the hydrologic cycle, it is the availability of freshwater that is of most concern today.
Thumbnail:The Colorado River at Horseshoe Bend, Arizona, a few miles below Glen Canyon Dam. Image used with permission (CC BY-SA 3.0).