Where is land subsidence a problem?

Half of all of the subsidence that has occurred in the United States has occurred in California. The most severely affected areas were in southern and western portions of the San Joaquin Valley as irrigated agriculture expanded.

Why is land subsidence a problem?

More than 80 percent of known land subsidence in the U.S. is a consequence of groundwater use, and is an often overlooked environmental consequence of our land and water-use practices. Increasing land development threatens to exacerbate existing land-subsidence problems and initiate new ones.

Where is land subsidence the greatest in the US?

The site is in the San Joaquin Valley southwest of Mendota, California. This photo shows the approximate location of maximum subsidence in the United States, identified by research efforts of Dr. Joseph F.

Where is land subsidence the greatest earth 103?

Some of the most drastic and best-known subsidence resulting from overuse of aquifers occurs in the San Joaquin and Sacramento Valleys of California, where the land level has subsided up to 10 meters in the last 90 years.

What is an example of land subsidence?

Land subsidence is the gradual settling or sudden sinking of land. Its primary causes are the removal of underground water, compaction, drainage of organic soils, underground mining, and thawing permafrost. In Connecticut, the main causes are subsurface soil loss after heavy rains and abandoned mine collapse.

Land subsidence, a growing problem

Which countries are faced with ground subsidence?

... subsidence due to groundwater extraction has been encoun- tered in many countries like China, Indonesia, Japan, Taiwan, Thailand, and Vietnam, especially in big cities where the water demands for municipal and industrial usages are very high such as Shanghai, Taipei, Jakarta, Tokyo, Bangkok, HCM City and Hanoi (see ...

How many states are affected by subsidence?

Subsidence is a global problem and, in the United States, more than 17,000 square miles in 45 States, an area roughly the size of New Hampshire and Vermont combined, have been directly affected by subsidence.

What causes land subsidence in California?

The main cause of subsidence in California is groundwater pumping. The effects of subsidence include damage to buildings and infrastructure, increased flood risk in low-lying areas, and lasting damage to groundwater aquifers and aquatic ecosystems.

What caused land subsidence in Mexico City?

In general, land subsidence in Mexico City occurs when large amounts of groundwater withdrawn from certain types of rocks, like fine-grained sediments. The water is partly responsible for holding the ground up, and then the rock compacts. We can say that when the water is withdrawn, the rocks can fall in on itself.

Where has subsidence become an issue in CA due to the overpumping of groundwater?

In the San Joaquin Valley of California, approximately 1 million people rely on groundwater for drinking. This high reliance on groundwater has resulted in overpumping of this resource, which leads to subsidence, or massive compression of the ground and arsenic contamination of the water.

Is New York sinking?

Since the 1950s, the sea level in the New York City area has already risen 9 inches. Scientific American reports that sea-level rise over the next century could rise 5 feet (plus or minus a foot) in the New York area.

Is Mexico City sinking?

As the aquifer is drained, Mexico City is sinking downwards rapidly at twenty inches per year. Despite heavy flooding and rainfall, the city is facing a water shortage. In fact, more than 20 million residents don't have enough water to drink for nearly half the year.

Is California sinking?

A Stanford University study simulates 65 years of land subsidence, or sinking, caused by groundwater depletion in California's San Joaquin Valley. The results suggest significant sinking may continue for centuries after water levels stop declining but could slow within a few years if aquifers recover.

What is land subsidence and what are the various causes responsible for it?

Land subsidence generally occurs when groundwater is mined in an unplanned way. The impact is more evident in rocks made of fine-grained sediments. Decline of groundwater table causes a vertical compression of sediments bearing the water.

What is the main cause of 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 are the effects of land subsidence?

Land subsidence causes many problems including: (1) changes in elevation and slope of streams, canals, and drains; (2) damage to bridges, roads, railroads, storm drains, sanitary sewers, canals, and levees; (3) damage to private and public buildings; and (4) failure of well casings from forces generated by compaction ...

How many cities are sinking?

At least 33 cities are falling by more than one centimeter per year, five times the rate of sea-level rise, based on recent estimates of global sea-level rise. The fastest-sinking cities, concentrated in South and Southeast Asia, are being forced to adapt.

Is Las Vegas sinking?

Land subsidence in the Las Vegas area is primarily related to ground-water withdrawal. Although the rate of subsidence has remained relatively constant for the last decade, recent urban development has intensified the occurrence of fissuring and structural damage.

Where else in the world has groundwater depletion caused subsidence?

This has happened in the Joaquin Valley and other regions of the world, such as New Orleans and Bangkok. These areas are now subject to severe flooding due to subsidence associated with groundwater removal. Total subsidence can usually be determined by ground-surface elevation surveys and GPS measurements.

What city is sinking in the USA?

Scientists say Mexico City has sunk past the point of no return, and that could mean infrastructure damage and water insecurity for millions.

Which North American city is sinking 3 feet per year?

Metropolitan Mexico City is the largest city in North America, with a population of over 21 million people. More than three-quarters of its drinking water comes from wells that extract water from the ground and continue to deplete the area's aquifers.

Is the Central Valley of California sinking?

The Central Valley has been sinking (subsiding) at differing rates since the 1920s and is estimated to have sunk up to 28 feet. During drought years, the valley is prone to accelerated subsidence due to groundwater extraction. California periodically experiences droughts of varying lengths and severity.

Is Washington DC sinking?

The land around the Chesapeake and near DC is also sinking. Wait—sinking? It's called subsidence, caused by natural changes in the earth's surface as the ice sheets melt and by groundwater withdrawal—pumping water out of wells. The rate of subsidence ranges around DC from about 1.5 to 2.5 millimeters per year.

Why is Houston sinking?

SUBSIDENCE: HOUSTON IS SINKING

In 1975, the Texas Legislature created the Harris-Galveston Subsidence District “to provide for the regulation of groundwater withdrawal for the purpose of preventing land subsidence.” The area is sinking due to groundwater withdrawal from underground aquifers.

How Fast Is New Orleans sinking?

New Orleans, Louisiana

Parts of New Orleans are sinking at a rate of 2 inches per year and could be underwater by 2100, according to a 2016 NASA study. Some parts of New Orleans are also 15 feet below sea level, and its location on a river delta increases its exposure to sea-level rise and flooding.