QUESTION 4 – Are there other serious problems of land subsidence beyond the well-known cases in the USA and Mexico City
QUESTION 4 – Are there other serious problems of land subsidence beyond the well-known cases in the USA and Mexico City?
Introduction:
In lecture, I introduced land subsidence as a problem caused by over-pumping of groundwater. The lecture specifically covered problems of Mexico City and San Joaquin Valley in California. These areas are important because they are among the most serious problems in the world. However, these are not the only places where serious subsidence is occurring. For example, the map insert below from the USGS (2004) shows the extent of problems in Santa Clara Valley, home of many of America’s technology companies.
Question Context:
The purpose of this week’s Packback exercise is to discover another example of subsidence, outside of the United States and Mexico City and to gain an appreciation of the prevalence of the problem. For your example, indicate how much subsidence has occurred and add some pictures or other information to describe briefly what specific problems have developed with your example. To help your search, refer to the article below from Triple Pundit (2021).
Bangkok, Thailand– a city sinking from land subsidence
Introduction
Cities around the world are sinking due to the increased occurrence of land subsidence. Kate Zerrenner of the Triple Pundit cited that, “19 percent of the world’s population, accounting for 21 percent of the world GDP, will be affected by land subsidence by 2040.” Not only are there environmental impacts of this issue, but health and economic ones as well. One city that is sinking at an accelerated rate is Bangkok, Thailand.
Issues in Bangkok
For the past 35 years, the city has relied on deep well pumping as a source for freshwater. Additionally, the city has a generally flat topography that sits on top of a clay aquitard. Each of these single factors has combined to exacerbate the existing problem. The subsidence reached its worst state in the 1980s when subsidence was at 120mm per year. As the city, and its population, grows, so does the amount of area that is being affected by subsidence.
The city has tried to cap the amount of groundwater pumping that is occurring, but despite the efforts being made, more than 2.0 million m3/day is being pulled up. As seen above, the subsidence is beginning to have issues on the infrastructure of the city and a threat its citizens.
Additional Sources
- https://www.circleofblue.org/wp-content/uploads/2014/12/Deltares_Sinking-cities.pdf
- https://www.sciencedirect.com/science/article/abs/pii/S0013795205002693
