What happens when groundwater is pumped out of the ground?
The depth and shape of the water table can also change dramatically when groundwater is pumped out of the ground. Pumping can quickly draw down the local water table right around a well. Over time, excessive pumping can also lower the water table over a wide region.
What happens if you pump too much water?
Excessive pumping can lower the groundwater table, and cause wells to no longer be able to reach groundwater. Increased Costs. As the water table lowers, the water must be pumped farther to reach the surface, using more energy. In extreme cases, using such a well can be cost prohibitive.
How does water get withdrawed from the ground?
For water to be withdrawn from the ground, water must be pumped from a well that reaches below the water table. If groundwater levels decline too far, then the well owner might have to deepen the well, drill a new well, or, at least, attempt to lower the pump. Also, as water levels decline, the rate of water the well can yield may decline.
What happens when groundwater levels decline?
If groundwater levels decline too far, then the well owner might have to deepen the well, drill a new well, or, at least, attempt to lower the pump. Also, as water levels decline, the rate of water the well can yield may decline. There is more of an interaction between the water in lakes and rivers and groundwater than most people think.
What percentage of watersheds are affected by groundwater extraction?
What percentage of watersheds are pumped?
How does groundwater affect the environment?
What is the hidden scaffold that propping up much of modern life?
How long did it take for the aquifers to fill?
Why is the San Pedro River declining?
What river was the last undammed?
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What happens if groundwater pumping exceeds groundwater recharge of the aquifer?
Excessive groundwater pumping can overdraft aquifers, emptying them faster than natural systems can replenish them. Overdraft can result in wells going dry, saltwater intrusion, depletion of surface water supplies, and cause the land to collapse (i.e., subsidence).
How does over pumping groundwater affect the aquifer?
When over-pumping stresses the aquifer system, wells pull more water from deeper clay soils. When pumps have to pull from deeper soils, the arsenic buried in the soil comes with it, mixing with the groundwater.
What can be caused by pumping out too much groundwater?
It can cause land subsidence, because as water is removed from the soil, it collapses and drops. Since groundwater that is very deep or below the oceans is saline, overpumping can cause the saltwater to move inland or upwards, resulting in saltwater intrusion, which can contaminate fresh drinking water.
What could happen if this well is over pumped?
Over pumping a well occurs when an attempt is made to draw water out of the well at a rate faster than the water can flow from the ground to the well pump. Usually, this over pumping will result in the well temporarily running dry, at least until the water flow can recover.
Groundwater Decline and Depletion | U.S. Geological Survey
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.
What percentage of watersheds are affected by groundwater extraction?
Already, somewhere between 15 and 21 percent of watersheds that experience groundwater extraction have slipped past a critical ecological threshold, the authors say—and by 2050, that number could skyrocket to somewhere between 40 and 79 percent.
What percentage of watersheds are pumped?
In the new analysis, de Graaf and her colleagues found that 15 to 21 percent of watersheds that pump groundwater are already past this threshold (about half of all watersheds worldwide are pumped).
How does groundwater affect the environment?
In the new research, the team took a global look at where groundwater is already being extracted at such a rate that it has caused water levels to drop so much in rivers and streams that they cross a critical environmental threshold: when water levels drop to less than 90 percent of the average flow during the dry season, the time when groundwater matters the most to river flow. Passing that threshold for more than three months of the year, for at least two years in a row, endangers the flora and fauna of freshwater systems, says Brian Richter, a water expert and scientist at Sustainable Waters.
What is the hidden scaffold that propping up much of modern life?
( Read about the vanishing Ogallala aquifer, one of the most important water sources in the western U.S.) Groundwater is the hidden scaffold propping up much of modern life.
How long did it take for the aquifers to fill?
But many of the aquifers from which this water is extracted took hundreds, or even tens of thousands of years to fill: The water inside may have percolated through cracks in the earth when giant ice sheets last covered New York City 20 thousand years ago.
Why is the San Pedro River declining?
The San Pedro River in Arizona has seen its flows decrease over the past few decades because of groundwater extraction nearby.
What river was the last undammed?
The last undammed river in the U.S. Southwest, the San Pedro of southwestern Arizona, used to gush and roil. Birds chirped and splashed on its banks when they stopped by on their migrations. Rare fish swam in its pools.
