USGS - science for a changing world

The USGS Water Science School

Special Topics in Water Science

Our Special Topics section lets you explore other water-science topic areas, such as water quality, urbanization and water, saline water, watersheds, runoff, and hydrology.

List of special topics

Learn about the water cycle, with a diagram in over 60 languages. Investigate the water cycle (in many languages!)

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General information about water quality. Acid rain. Groundwater quality. Pesticide residue in groundwater. E. coli and colliform bacteria in water. Phosphorus in water, from runoff, and possible problems. Nitrogen in water from runoff, and problems that can occur. How urbanization affects the hydrologic system. Urbanization and water quality. How water is used in cities. How much of each state is covered in water. Tsunami Hazards-A National Threat What is a watershed? Precipitation runoff over the landscape. Impervious surfaces and the effect on runoff and flooding. Saline water Uses for saline water. Why is the ocean salty? Desalination of saline water to fresh water. Calculate how much a dripping faucet wastes. Are raindrops tear shaped? Fictional story of how water is important in a new town. What is the field of hydrology? How hydrologists find water underground. What is water dowsing?