A study Land subsidenze risk to infrastructure in us metropolises Posted by magazine Nature Cities warns about him soil sinking risk In the main urban areas of the United States, a growing threat promoted, mainly, by the groundwater extraction.
According to the report, at least the 20% of urban areas In the 28 largest cities in the country they have significant levels of Subsidency of the landdirectly affecting more than 34 million people.
Subsidy threats key infrastructure
The phenomenon of survey, which consists of the Progressive descent of soil levelrepresents a serious threat to urban infrastructure.
The study highlights that Buildings, foundations, roads, bridges and dams They are the most vulnerable elements for the effects of Differential sinking of the terrain.
When this sinking occurs quickly or unequally, you can compromise the Structural integrity of these constructions, raising maintenance and repair costs.
In addition, it is estimated that more than 29 thousand buildings They are located in areas of High riskwhich represents a challenge for urban planning and sustainability in the United States.
Why does the ground sink?
The report explains that the Excessive extraction of groundwater It is one of the most determining factors of sinking.
By extracting water at a rate greater than that of its Natural rechargedecreases pore pressure In aquifers, which causes sediment compaction, especially those of fine grain. This process leads to surface sinking, also known as Subsidy.
This phenomenon is particularly pronounced in confined aquiferswhere the relationship between the low of the water table and the sinking of the terrain is more evident.
However, the conditions local hydrogeological They can greatly influence the speed and magnitude of the process.
Urban Sinking Radiography: Analysis of cities with greater risk
The report provides a detailed analysis of the Risk of terrain of 28 cities in the United States, evidencing how factors such as the type of aquifer groundwater extraction and local geological conditions directly influence the magnitude of the problem.
Houston, Texas
It is one of the cities with the highest rates of soil sinkingovercoming the 4 mm per year.
This rapid subsidence is mainly related to the Intensive groundwater extraction and industrial activities.
Dallas and Fort Worth, Texas
Both areas record similar rates, also above 4 mm per yearreflecting a strong exploitation of aquifers and a significant risk for urban infrastructure.
Chicago, Illinois
Exhibits average rates of 2 to 3 mm per yearwith variations within the metropolitan area.
In this city, the Subsidy It is a consequence of natural processes and human activity.
New York, New York
Presents more moderate rates, between 1 and 2 mm per year. In this city, sinking is associated with tectonic processesthe weight of constructions and the extraction of natural resources.
San Francisco, California
Show variable rates, with some critical points or Hotspots that reach until 3 mm per year. Causes combine urban load (construction, traffic) and sediment compaction.
Las Vegas, Nevada
Records some of the highest rates, reaching 3.5 inches per year (approximately 9 cm), as a result of on water extraction in arid areas and sedimentary.
Phoenix, Arizona
Also face High Subsidy Rateswith values similar to Las Vegas (up to 9 cm per year), mainly due to the Overexploitation of aquifers in an environment of low natural water recharge.
Los Angeles, California
Has estimated rates of 2 to 3 mm per yearwith critical areas linked to water extractions both in urban and peri -urban areas.
Detroit, Michigan
Record one Low Subsidyclose to 1 mm annualmainly attributed to natural processes and lower pressure on aquifers.
This panorama shows that the land subsistence It varies considerably between regions. The Southwest citiesespecially in Texas, Arizona and Nevadaface a much higher risk, with rates that can exceed 9 centimeters per year.
In contrast, cities of the east and a half west experience a more moderate sinking, of 1 to 3 mm per yearalthough also influenced by human and natural factors.
The report clarifies that the relationship between groundwater extraction and soil sinking It is not always linear at the regional level. This suggests that other factors, such as land characteristics, land use and human activities, also influence Urban vulnerability.
Strategies to mitigate the sinking of the land
To face this phenomenon, researchers propose a series of strategies that can be adopted by local and national governments:
- Continuous monitoring: The use of technologies such as Synthetic Opening Radar Interferometry (INSAR) It allows to map and monitor in real time the areas most affected by the subsidence, improving the early response capacity.
- Sustainable Water Management: It is recommended to reduce extraction rates, implement projects from Artificial aquifer recharge and strengthen consumption control policies to guarantee the integrity of water resources.
- Smart urban planning: The sinking risk must be integrated into urban development plans. This implies restricting constructions in high -risk areas and designing infrastructure resistant to soil movements.
- Infrastructure reinforcement: Buildings, roads and bridges must be adapted to support land displacements. In some cases, even the Infrastructure relocation in highly vulnerable areas.
- Citizen Education and Participation: The report underlines the importance of campaigns of awareness of the responsible use of water and the need to involve communities in decision making.
- Integrated policies and multisectoral collaboration: It is proposed to establish participatory regulatory frameworks that integrate scientists, local authorities and community organizations, promoting an approach adaptive, cyclic and data -based.
Towards an urban resilience
The study concludes that the Sinking of the terrain It is not an inevitable phenomenon, but a challenge that can be managed with proper planning, monitoring technologies and a Collaborative governance.
Guarantee the cities resilience Given the subsidence, it will be key to protecting both the critical infrastructure and the well -being of millions of people.