parts of the Iranian capital Tehran versa, hide in the underground. The cause, in the end, the reason the water was missing in a recent study. The effect is known, among others from Mexico city, where the city centre has fallen in recent years to several meters. The natural water reservoirs in the substrate to be filtered, faster than the water could follow, and the soil in bags with alarming speed. This experts of the German research centre for Geosciences Potsdam (GFZ) have been measured in Tehran.
The Metropolitan region, with its estimated 20 million inhabitants, and the farms of the surrounding region consume much more water than the underground has to offer. So it is that parts of the urban area as well as areas fall in the wider area, with considerable speed, in part by a quarter of a meter per year. Reporting Mahdi Motagh and Mahmud Haghshenas Haghighi from the section of remote sensing of the GFZ in the journal Remote Sensing of Environment.
The high water consumption is due not only keep the urban house. Iran has expanded in the past 40 years, agriculture in the fertile North of the country, where Tehran is located. Large quantities of water are needed for agriculture.
in addition To the many unregulated water abstraction dams, which are built by the government to support the farmers. The pent-up water can't flow in the natural ground water reservoir.
The massively increasing consumption of water shows above ground at the Urmiasee in the North-West of the country. The as large as lake Constance, is internal waters, once ten times in the past few years, with terrifying speed dried up. The salt content already resembles that of the dead sea between Israel and Jordan. Of the original surface, only a fraction is left.
it was Already known that the groundwater level has fallen in the city of Tehran between 1984 and 2011 in order to twelve meters. Motagh, and Haghshenas from the GFZ have now documented the sinking of the soil in the Metropolitan region of Tehran, as well as in the wider area, with radar satellite data.
The sagging of the soil affects about one-tenth of the urban area and extends far into the outer areas of the largest metropolis in Western Asia – even to the far outside past the international airport, where the rate of descent of the floor is five inches per year.
As a data source, a plurality of earth observation served to satellites, which scan the surface of the planet with micro-waves. The European satellite Sentinel-1 provides, for example, all twelve days an accurate picture of the topology of Tehran and its surrounding areas. It shows that some areas between 2003 and 2017, with the frightening Rate of 25 centimeters per year decrease. The cracks declared in buildings and crevices in the soil, which have been observed in the past few years. In the southwest of Tehran is already more unstable become the building had to be demolished. In the rural Southeast of the Iranian capital of km to see long cracks in the ground.
The Lowering of the soil leads also to the fact that the underground cavities disappear for groundwater, and the original state will never hire again. Because of this, a rain water run-off worse, and also increases the risk of Flooding.
From the in the professional world, "Subsidenz" phenomenon are not only affected metropolises of emerging countries (in Indonesia's capital, Jakarta, 20 inches per year were measured), but also in developed Nations. In Parts of California the soil from the bags with a similar speed. (hach)
Created: 11.12.2018, 11:28 PM