How does over pumping cause subsidence?

How does over pumping cause subsidence?

When over-pumping stresses the aquifer system, wells pull more water from deeper clay soils. When the water is removed, the weight of soil and rock crush the air pockets which once held water. The land above the aquifer sinks and settles through subsidence, permanently compacting the aquifer.

Why does ground subsidence occur?

It occurs when groundwater is withdrawn from a basin aquifer or subsurface reservoir faster than natural or artificial recharge can replace it. In the case of shallow groundwater aquifers in the Southwest, rapid withdrawal of groundwater causes regional groundwater levels in a basin to decline.

What happens when too much groundwater is pumped?

The most severe consequence of excessive groundwater pumping is that the water table, below which the ground is saturated with water, can be lowered. For water to be withdrawn from the ground, water must be pumped from a well that reaches below the water table.

What are the effects of ground subsidence?

Subsidence causes permanent inundation of land, aggravates flooding, changes topographic gradients, ruptures the land surface, and reduces the capacity of aquifers to store water.

Where does subsidence occur?

Land subsidence occurs when large amounts of groundwater have been withdrawn from certain types of rocks, such as fine-grained sediments. The rock compacts because the water is partly responsible for holding the ground up. When the water is withdrawn, the rocks falls in on itself.

Why does earthquake induced subsidence occur?

Subsidence may occur as the result of either natural or human-caused events. Earthquakes are commonly associated with subsidence. When two blocks of the earth’s crust slide against each other, causing an earthquake, ground movement may occur, raising or lowering the ground surface.

What are two consequences of aquifer overuse?

Summary. When water is pumped from an aquifer, the water table declines and wells must be drilled deeper. Ground subsidence and saltwater intrusion are two possible consequences of groundwater overuse.

How does groundwater affect the environment?

Some human activities, such as pumping water into the ground for oil and gas extraction, can cause an aquifer to hold too much ground water. Too much ground water discharge to streams can lead to erosion and alter the balance of aquatic plant and animal species.

What causes subsidence?

Subsidence – sinking of the ground because of underground material movement—is most often caused by the removal of water, oil, natural gas, or mineral resources out of the ground by pumping, fracking, or mining activities.

What is water subsidence?

How does land subsidence contribute to water pollution?

How does land subsidence contribute to water pollution? Using sinkholes as landfills can cause pollutants to seep into groundwater. Sinkholes usually form when the ground becomes wet and things sink into them after a big rainstorm.

What is the meaning of groundwater related subsidence?

Groundwater-related subsidence. Groundwater-related subsidence is the subsidence (or the sinking) of land resulting from groundwater extraction. It is a growing problem in the developing world as cities increase in population and water use, without adequate pumping regulation and enforcement.

Why is groundwater a problem in the US?

It is a growing problem in the developing world as cities increase in population and water use, without adequate pumping regulation and enforcement. One estimate has 80\% of serious U.S. land subsidence problems associated with the excessive extraction of groundwater, making it a growing problem throughout the world.

What are the effects of over pumping of groundwater?

Lowering of the Water Table. 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.

What is the main cause of groundwater depletion?

Groundwater depletion is primarily caused by sustained groundwater pumping. Some of the negative effects of groundwater depletion: Lowering of the Water Table. Excessive pumping can lower the groundwater table, and cause wells to no longer be able to reach groundwater.