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WATER. Humans can survive a month without food, but will only live a few days without water Fresh water ~ water that people can drink Salt water ~ water in the ocean Water can be found as a solid, liquid , or gas Water is a renewable resource that is constantly being circulated.
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WATER • Humans can survive a month without food, but will only live a few days without water • Fresh water ~ water that people can drink • Salt water ~ water in the ocean • Water can be found as a solid, liquid, or gas • Water is a renewable resource that is constantly being circulated
The Water Cycle CONDENSATION EVAPORATION PRECIPITATION PERCOLATION RUNOFF
3% fresh water 1% 22% 77% 97% salt water
Where is the water? • Surface water = fresh water on the Earth’s surface • River systems • water from rain and melting snow runs off from mountains, hills and other high places • the water runs into streams • many streams combine to form rivers • The Mississippi, Amazon, and Nile are enormous river systems
Mississippi River and its tributaries Gulf of Mexico
Groundwater • Groundwater is water beneath the Earth’s surface in soil and rock formations. • Aquifer is an underground formation that contains groundwater • Water table is the level where rocks and soil are saturated (filled up) with water • The water table can be just below the surface or hundred’s of feet below ground
How caN THERE BE WATER IN ROCK? • Porosity: The percentage of the total volume of rock or soil that has spaces (pores) • In an aquifer, the groundwater occupies the pores • The higher the porosity, the more groundwater rock or soil can hold • The soil is called saturated when the pores are holding as much water as possible
How does the water get into the rock? Permeability = The ability of rock or soil to allow water to flow through it • Materials that allow water to flow are permeable • Materials that do not allow water to flow are impermeable • Water on the surface percolates through the ground and ends up in the pore spaces as groundwater
What is a drinking Water Well? Aquifer recharges as water percolates through the overlying soil to reach the aquifer aquifer