Goundwater

Goundwater

INTRODUCTION

Although 70 percent of the Earth's surface is covered by water, 97 percent of it is contained in the oceans and is too salty to drink (Cunningham and Saigo, 1992). Therefor, fresh water is a precious resource that in some areas of the world is so scarce, that people will fight wars over it. About 25 percent of the world's fresh water is groundwater. Although groundwater is not as accessible as surface water (lakes, rivers and streams), people are willing to dig wells to obtain it in areas where the climate is too dry to allow much surface water. Many farmers pump water from wells to support irrigation. This is often done with windmills, a very cheap form of energy. In some dry areas like Arizona, large cities use groundwater for their entire water supply. Although groundwater is an excellent water source, there are many complications. For example, it is a resource that is difficult to assess since it is not directly visible. Therefor with out complicated measurements, it is hard to say how much water there is left in your well. It is also difficult to tell where exactly the source of recharge for your well is. Thus if an area near your well becomes polluted, the pollution may seep into the groundwater feeding your well.
The purpose of this project is to explore the subject of groundwater, its place in the water cycle, how it seeps through the ground and how it accumulates in underground pockets called aquifers. The project will also examine the many uses of groundwater in agriculture as well as environmental problems that are presently threatening the quantity and quality of groundwater reserves.

THE WATER CYCLE

The water cycle is a constant movement of water in the air, in the ground and on the surface of the Earth. It starts when water evaporates from plants, the ground, lakes, rivers and oceans. This is called evapotranspiration.
As the vapor rises, the surrounding air gets colder and colder. The dew point is the temperature at which water begins to condense (change into it's liquid form). At the dew point, it clouds form. Clouds consist of tiny water droplets which remain suspended in the air until they become too large for turbulence to hold up. When this happens, some form of precipitation (rain, hail or snow) falls on the earth and either seeps into the soil or flows across the surface. Most of the time, it does both. Whatever doesn't evaporate or run off infiltrates into the ground and is called groundwater. When it flows across the surface it is called surface runoff. The surface runoff goes into an ocean, river or stream where it evaporates in to the atmosphere again.
Water infiltrates deeper and deeper through the ground until it eventually reaches a water table, which is the point where water becomes...

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