Which condition may result in surface subsidence?

Which condition may result in surface subsidence?

Subsidence can be caused by any process that results in lowering of the water table. So, drought, dry seasons, and excessive withdrawal of groundwater by humans can cause the water table to move to deeper levels and result in subsidence.

What is the source of pollution in the gravel aquifer?

There are many causes for groundwater contamination. Some examples are improper management of feedlots, improper storage and use of hazardous materials, accidental chemical spills, leaking septic tanks, improper waste disposal, and corrosion.

Is it difficult to cause drawdown in an aquifer?

It is very difficult to cause drawdown into an aquifer, no matter how many wells are tapped into the aquifer. Groundwater recharge is faster during periods of heavy precipitation. Water is able to flow more easily through the aquifer because its material has a high permeability.

What is produced in limestone regions that have sinkholes and sinking streams?

Karst topography describes limestone regions that have sinkholes, sinks, and sinking streams.

Can flooding cause subsidence?

Subsidence can occur when the weather alters the ground below your property. Likewise, properties built on floodplains or areas prone to flooding are susceptible as the soil can become saturated and wash away from the foundations by excessive water.

How is subsidence caused?

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.

Which one is the important cause for underground water pollution?

Across the world, septic systems are the main cause of pollution of underground water. Additionally, improperly designed and leaking septic systems release contaminants such as nitrates, oils, bacteria, chemicals, detergents, and viruses into underground water.

What is water drawdown?

Drawdown: The drawdown in a well is the difference between the pumping water level and the static (non-pumping) water level. Drawdown begins when the pump is turned on and increases until the well reaches “steady state” sometime later.

What is drawdown in irrigation?

0 votes. Due to pumping out of ground water through wells and other sources of water from ground , water table which is initially at some elevation decreases. The height of water column decreased is termed as drawdown.

Why are most caves formed in limestone?

Limestone caves, which are formed primarily by rainwater and snowmelt, are by far the most numerous of all cave types. This carbonic acid continues to seep into the soil and through the limestone until it reaches the water table, which is the upper limit at which ground is saturated with water.

Which of the following is often found in groundwater and dissolves limestone to form caves?

Cave Formation Carbonic acid is especially good at dissolving the rock limestone. Working slowly over many years, ground water travels along small cracks. The water dissolves and carries away the solid rock gradually enlarging the cracks, eventually forming a cave.

How are caves formed?

Most caves are thought to form near the water table (the surface below which all open space in rock is filled with water) , and thus the openings are initially filled with water.

What are subsidence hazards?

Subsidence hazards involve either the sudden collapse of the ground to form a depression or the slow subsidence or compaction of the sediments near the Earth’s surface.

What happens when a sinkhole collapses?

When sinkholes collapse to expose the water table at the surface, the sinkhole will be filled with water forming small circular lakes. Although common in areas underlain by limestone, sinkholes can form in any area where highly water soluble rocks occur close to the surface.