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Water Underground: 

Water Underground By Mrs. Leland March 26, 2006

Key Concepts: 

Key Concepts What are permeable materials? What is the water table? What is an aquifer? What are factors that you should know when building a well? What are springs and geysers?

Groundwater: 

Groundwater The amount of water underground, or groundwater, is dependent upon several things: The amount of precipitation The slope of the hill The surface of the ground

Underground Layers: 

Underground Layers Underground water will trickle between the layers and spaces underground. The following things can affect where it goes: Pores-These are the spaces between rock and soil. Water will move more easily through these spaces if they are bigger, like sand and gravel. These spaces are permeable allowing water to seep through. If water can’t pass through a layer, it is impermeable. Clay and granite are examples.

The Impermeable Layer: 

The Impermeable Layer Since water can’t soak through, it becomes trapped and totally fills up, or saturates, the space. This is called the saturated zone. The top of this zone is the water table. While soil and rock above the water table contain some water, they also contain air. This layer is called the unsaturated zone.

Aquifers: 

Aquifers Any underground layer of rock or sediment that holds water is called an aquifer. An aquifer can be very small or the size of several states. Groundwater can move. Some will only travel a few centimeter a day, equally about 10 meters a year. But others travel through hundreds of kilometers in one year.

Bringing Groundwater to the Surface: 

Bringing Groundwater to the Surface The level of the water table usually follows rock layers. Heavy rains or snow can raise the level of the water table. Sometimes the water table meets the ground surface. Then it becomes a pond or a spring. But there are other ways to get the water to the surface. Wells A well is created when drilling goes well below the water table. If the water table drops during the dry season, either dig deeper or wait until rainfall Artesian Well Sometimes groundwater is trapped between 2 impermeable layers so it is under great pressure. If the top layer of rock is punctured, then the water spurts up. It rises to the surface on its own. This is an artesian well.

Springs and Geysers: 

Springs and Geysers Groundwater the comes to the surface and bubbles or flows from cracks in the rock are called springs. Usually the water is normal temperature, but sometimes in can be hot. This is because there are hot rocks below the surface that warm it. A geyser is a type of hot spring from which the water occasionally bursts in the air. Geyser is an Icelandic word, geysir, that means gusher. Geysers are formed when very hot water begins to rise through cracks in the rocks. Steam builds up pressure in the partially blocked passages. Finally it erupts.

Key Concepts: 

Key Concepts What are permeable materials? Permeable materials are those that allow liquids to flow through them. Gravel and sand are examples. What is the water table? The water table is the top layer of the saturated zone underground. What is an aquifer? An aquifer is any underground layer of rock or sediment that holds water. What are factors that you should know when building a well? When you are building a well you should know what level the water table is and if the well might dry up during the year. Cost factors for drilling are also important to know. What are springs and geysers? Springs are made by water that bubbles up from underground through cracks in the rock. They can be heated by the rocks. Geysers are pressurized water that is forced through the cracks underground at different intervals.