Hydrology is the science of water. It deals with the origin, distribution, and properties of water on Earth and other planets. Hydrologists work to solve water- related problems. They consider water use from a variety of perspectives- social, economic, legal, scientific, and environmental- to determine how differing viewpoints affect the quality and quantity of a community's water supply. They study pollution carried by water- including oceans, rivers, streams, rain, snow, and ice- and devise methods to clean and control it. Some study weather- related problems such as flood forecasting, drought management, acid rain, and global warming. Others manage water resources so that the goals of all water users are achieved efficiently while protecting the environment.