WATER 101 



Not all the water that falls from the clouds sinks to the 

 underground reservoir. When more water falls on the soil 

 than can be absorbed by it, the water runs off the surface into 

 the streams. This water is called run-off. 



GtOUND WATf* 1O OC 



THE HYDROLOGIC CYCLE 



The circular route of water from s\y to earth to sea to s\y 



The second half of the hydrologic cycle shows how this 

 precipitation is returned to the clouds from which it will again 

 fall. The run-off and ground water flow into the rivers, lakes, 

 and finally the ocean. Wherever this water is exposed to the 

 atmosphere it is drawn up to the clouds. This is evaporation. 

 A large part of the water, however, does not flow into the 

 streams; it is sucked up by the roots of plants and exhaled into 

 the atmosphere by the leaves. This is transpiration. This ex 

 haled moisture is also returned to the clouds. 



THE WORK OF WATER 



If you were to map this circular course of water, the route 

 would be marked this way. From precipitation to infiltration, 

 to ground water, to surface water, and by evaporation back to 



