Millions of cubic miles of water exists in the ground. You can't see it, but not only is it there, it is always moving around -- mostly downward, but also horizontally. Moving groundwater helps keep rivers full of water and allows for people to draw out water via wells. Moving groundwater is an important part of the water cycle.
Wells are extremely important to all societies. In many places wells provide a reliable and ample supply of water for home uses, irrigation, and industries.
Where surface water is scarce, such as in deserts, people couldn't survive and thrive without groundwater, and people use wells to get at underground water. Groundwater is a valuable resource both in the United States and throughout the world. Groundwater depletion, a term often defined as long-term water-level declines caused by sustained groundwater pumping, is a key issue associated with groundwater use.
Many areas of the United States are experiencing groundwater depletion. Groundwater decline is a real and serious problem in many places of the Nation and the world. When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall, and the depth to water in wells increases. Below are publications associated with aquifers and groundwater.
In addition to those below, Water sources: groundwater by Environment and Climate Change Canada may be of interest. Most of us don't have to look for water. We grew up either in big cities where there was a public water supply, or in small towns or on farms where the water came from wells.
But there are some people to whom finding a new supply of water is vitally important. The importance of considering ground water and surface water as a single resource has become increasingly evident. Issues related to water supply, water quality, and degradation of aquatic environments are reported on frequently.
The interaction of ground water and surface water has been shown to be a significant concern in many of these issues As the salesmen sang in the musical The Music Man, "You gotta know the territory. Learn as much as possible about the land, the water supply, and the septic system of the house before buying or building.
Do not just look at the construction aspects or the beauty of the home and When you open the faucet you expect water to flow. And you expect it to flow night or day, summer or winter, whether you want to fill a glass or water the lawn.
It should be clean and pure, without any odor. You have seen or read about places where the water doesn't have these qualities. You may have lived in a city where you were allowed to water Below a certain depth, the ground, if it is permeable enough to hold water, is saturated with water. The upper surface of this zone of saturation is called the water table. The saturated zone beneath the water table is called an aquifer, and aquifers are huge storehouses of water.
What you are looking at in this photo is a "well" that exposes the water table, with an. The ground beneath our feet is not just rock, or at least, not just one kind of rock. Many different types of rock exist, and they have very different properties. Often, different types of rocks exist in horizontal layers beneath the land surface.
Some layers are more porous than others, and at a certain depth below ground the pores and fractures in these rocks can be. Pumping has removed water from storage in basalt aquifers and caused declines in many areas of the Columbia Plateau. Skip to main content.
Search Search. Water Science School. Aquifers and Groundwater. Groundwater Photo Gallery Learn about groundwater through pictures Visit the gallery. Get GW data. Groundwater Information by Topic Learn more. Science Center Objects Overview Related Science Publications Multimedia A huge amount of water exists in the ground below your feet, and people all over the world make great use of it. Learn the basics about water using our Water Primers! Credit: Environment and Climate Change Canada.
Below are other science topics related to aquifers and groundwater. Date published: October 9, Filter Total Items: 7. Sign In. KQED Inform. Save Article Save Article. Melanie Eirich. Mar 26, Failed to save article Please try again. Why are aquifers important?
Is it possible for an aquifer to run dry? Why or why not? Which state in the U. Is an Aquifer an Underground River? Almost all aquifers are not rivers. Since water moves slowly through pore spaces in an aquifer's rock or sediment, the only life-forms that could enjoy floating such a 'river' would be bacteria or viruses which are small enough to fit through the pore spaces. True underground rivers are found only in cavernous rock formations where the rock surrounding cracks or fractures has been dissolved away to leave open channels through which water can move very rapidly, like a river.
Ground water has to squeeze through pore spaces of rock and sediment to move through an aquifer the porosity of such aquifers make them good filters for natural purification.
Because it takes effort to force water through tiny pores, ground water loses energy as it flows, leading to a decrease in hydraulic head in the direction of flow. Larger pore spaces usually have higher permeability, produce less energy loss, and therefore allow water to move more rapidly. For this reason, ground water can move rapidly over large distances in aquifers whose pore spaces are large like the lower Portneuf River aquifer or where porosity arises from interconnected fractures.
Ground water moves very rapidly in fractured rock aquifers like the basalts of the eastern Snake River Plain. In such cases, the spread of contaminants can be difficult or impossible to prevent. What does an aquifer look like? Every aquifer is unique, although some are more generic than others. The boundaries of an aquifer are usually gradational into other aquifers, so that an aquifer can be part of an aquifer system. The top of an unconfined aquifer is the water table.
A confined aquifer has at least one aquitard at its top and, if it is stacked with others, an aquitard at its base. Figure 1 shows an example of an aquifer system in the lower Portneuf River valley. The diagram represents a cut-away perspective view of this system of multiple aquifers and is greatly exaggerated in its vertical scale to show some of the details.
0コメント