The Urmia Lake Bridge or Urmia Lake Causeway is a road bridge in northern Iran. It is the largest and longest bridge in Iran, and crosses Lake Urmia, connecting the provinces of East Azerbaijan and West Azerbaijan. The project was completed in November 2008. The bridge reduced the driving distance between Tabriz and Urmia by , saving time and fuel consumption, and reducing road accidents. It has helped stimulate cultural exchanges, tourism and trade between the provinces of East Azerbaijan and West Azerbaijan.

History

A project to build a highway across the lake was initiated in the 1970s but was abandoned after the

Iranian Revolution The Iranian Revolution ( fa, انقلاب ایران, Enqelâb-e Irân, ), also known as the Islamic Revolution ( fa, انقلاب اسلامی, Enqelâb-e Eslâmī), was a series of events that culminated in the overthrow of the Pahlavi dynas ...

of 1979, although a

causeway A causeway is a track, road or railway on the upper point of an embankment across "a low, or wet place, or piece of water". It can be constructed of earth, masonry, wood, or concrete. One of the earliest known wooden causeways is the Sweet Tra ...

with an unbridged gap had already been completed. The project was revived in the early 2000s, and was completed in November 2008 with the opening of the bridge across the remaining gap. The bridge was planned for the length of 1,276 meters with 19 spans, comprising a central 100 meter main span and nine spans each side. The main span is in the form of an overhead tied arch and is 20.1 meters in height. It allows for shipping underneath. The highly saline environment is already causing heavy rusting of the steel on the bridge, despite anti-corrosion treatment.

Synthetic Aperture Radar imagery

Multisensor InSAR analysis from 4 different satellite sensors (i.e.

Envisat Envisat ("Environmental Satellite") is a large inactive Earth-observing satellite which is still in orbit and now considered space debris. Operated by the European Space Agency (ESA), it was the world's largest civilian Earth observation satell ...

, ALOS-1, TerraSAR-X and Sentinel-1) in a period of 13 years (2004-2017) revealed that a long-term consolidation on the causeway is present. The rate of consolidation (in satellite's look direction) of the causeway peaked at 90 mm/year between 2012 and 2013. The soil consolidation of the causeway is not unusual, but if the settlement that has occurred since 2004 continues into the future, the causeway might be damaged by uneven settlement rates in the east and west embankments.

Environmental impact

Environmentalists have warned that the construction of the causeway for the bridge, along with other ecological factors, will contribute to the drying up of Lake Urmia, turning it into an

inland salt marsh An inland salt marsh is a saltwater marsh located away from the coast. It is formed and maintained in areas when evapotranspiration exceeds precipitation and/or when sodium- and chloride-laden groundwater is released from natural brine aquifers. It ...

, and adversely affecting the climate of the region. They state that the gap in the causeway is not wide enough to permit an adequate flow between the two portions of the lake. The presence of increased numbers of

halobacteriaceae In taxonomy, the Halobacteriaceae are a family of the Halobacteriales in the domain Archaea.See the NCBIbr>webpage on Halobacteriaceae Data extracted from the ''Halobacteriaceae'' represent a large part of halophilic Archaea, along with member ...

in the northern portion of the lake is indicative of the increasing

salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

of the water.

Footnotes

External links

{{Portalbar, Iran 2008 establishments in Iran Roads in Iran Bridges in Iran