Beijing dropping by up to 4 inches a year, study shows.
An international study led by Beijing-based researchers has discovered that the city is dropping by as much as 11 centimeters (4 inches) in some districts per year. According to the Chinese government, 46 cities across China are sinking into the ground. In the last decade alone, Beijing has sunk 14 inches. The city continues to sink at a rate of nearly 11 centimeters per year.
The study, conducted by an international team of seven scientists and engineers is based on InSAR radar technology, which monitors land elevation changes.
The thirsty city has depleted its groundwater, which the study identified as the cause of the sinking.
Using satellite imagery and GPS data, the team analyzed topographical trends from 2003 to 2010 and found that the city, which has a population of over 20 million, was sinking at an alarming rate. Its central districts are among the worst affected, the study says.
The main subsidence bowls are distributed over the Chaoyang, Changping, Shunyi and Tongzhou districts. Chaoyang, in the eastern suburbs, is the worst affected, with subsidence of 11 cm per year. Beijing is ranked as the fifth most water-stressed city in the world, the study notes, and as China continues to urbanize, the stress on subterranean aquifers is only set to worsen. Living a nightmare in China’s city of sinkholes
In Beijing, groundwater is the main water source – two thirds – for everything from industrial and agricultural use to household consumption. China media outlet Sina estimates that the capital requires 3.5 billion liters of water per year. As the water, which has accumulated over thousands of years, is extracted in increasingly greater volumes, the now-dried up soil compacts. The rapid sinking could affect buildings and public works projects, including the city’s rail network.
This sinking phenomenon, called subsidence, has a number of causes. The rapid construction of massive buildings, roads, and other infrastructure projects has put a lot a weight on the ground.
Excessive pumping of groundwater is also a major problem that plagues thirsty urban areas as they struggle to keep up with rising populations and water demand. Both Shanghai and Beijing have struggled with overtaxed aquifers.
The high flood wasn't caused by just heavy rainwater. The Chinese government authorized emergency discharges of overflowing water from dam reservoirs. This was done to prevent the city of Beijing from getting flooded by the overflowing water reservoir. The same reservoir was holding back the water from flooding the downstream village. The few were sacrificed to protect the many, but rather than compensate the villager by declaring it as flood discharge from the dam, the government put all the blame on heavy rain. This denied any compensation the village was entitled to. The villager then protest in front of government buildings, demanding compensation for the dam discharge that flooded their village. The government sent police to put down these protesters rather than supporting villagers who have lost everything.