The Hydrosphere
Water on Earth 97 Percent of the worlds water is in oceans and too salty to use Salt in the ocean can be removed through desalinization – Very dry regions in the world use this process to get freshwater Less than 3% of the world’s water is fresh Most of this water is frozen Remainder is less than 1%-found in clouds, lakes, and rivers
The Hydrologic Cycle The physical state is always changing from gas to liquid to solid This movement of water through the hydrosphere is called the hydrologic cycle – Solar energy changes the water to vapor (evaporation) – As vapor rises it forms tiny liquid droplets (condensation) – Droplets join to form clouds, grow to become rain drops (precipitation)
Surface Water Precipitation falls onto Earth and it flows down hills and mountains towards the lowlands and coasts Headwaters: first and smallest streams from this runoff Headwaters join and form larger streams and eventually form rivers Any smaller stream or river that flows into a larger stream or river is called a tributary – The Ohio, Arkansas, and Missouri Rivers are all major tributaries of the Mississippi River The region drained by a river and its tributaries is called a watershed or drainage basin
Surface water may also collect in lakes Lakes can be carved by glaciers like the Great Lakes Lakes can also be created by runoffs from mountains Surface water is also found in estuaries: where a river meets an inlet, small arm, of the sea – Chesapeake Bay on the Atlantic Coast
Surface water is also found in wetlands: covered with water for at least part of the year – Marshes, swamps, etc..
Groundwater Water below the ground Water sinks into the ground and it is stored by the soil Plant roots take this water Water slowly moves down and eventually creates the water table Groundwater can be used by pumping the water out
Floods When rivers carry more water than the stream can hold Result of heavy rains or sudden snow melts They erode the land and destroy vegetation Flooding increases if rainwater cannot sink into the soil