Wednesday, January 20, 2010

Karoon River

The Karoon River (رودخانه کارون) is Iran's most effluent, and its only navigable, river. It is 720 km long and rises in the Zard Kooh mountains of the Bakhtiari district in the Zagros range, receiving many tributaries, such as the Dez and the Koohrang, before passing through the capital of the Khuzestan province of Iran, the city of Ahvaz.  

The Karoon continues toward the Persian Gulf, forking into two primary branches on its delta: the Bahmanshir and the Haffar that joins Arvand River, emptying into the Persian Gulf. The important Island of Abadan is located between these two branches of the Karoon. The port city of Khorramshahr is divided from the Island of Abadan by the Haffar branch. Seasonal variation in discharge rate shows the lowest water level to be in October, and the highest, as the result of combined precipitation and meltwater, in April.  

Studies undertaken by a group of Belgian scientists suggest the Karoon River has taken a central course, abandoning its westward course over the last 6,000 years. Formerly the Karoon had a lower course that was separated from and to the east of Arvand River. There are three old riverbeds (apparently used successively) that branch off at the left of the Karoon; they are known as Shatt al-Qadimi, Shatt al-Ameh, and Bahmanshir River. Bahmanshir River delimits the eastern edge of the island of Abadan. In 1765, however, the river changed to its present course through the apparently artificial Haffar Channel. According to the geographer al-Maqdisi, this channel was dug in 986 to facilitate water communication between Ahvaz and Basra. This change resulted in frontier disputes between the Ottoman Empire and Iran, disputes that were settled by the treaty of Erzurum (1847), giving Iran access to the eastern bank of Arvand River and the right to use the waterway.  

The Karoon up to Ahvaz was opened to international navigation in 1888, and boat services were later established between Ahvaz and Band Qir. Shipping on the lower course of the Karoon has become increasingly important owing to oil drilling and refining in the vicinity. To increase the water supply of Isfahan, a dam and tunnel on the river were completed in 1971.  

The river banks consist of seasonally flooded arable land with scattered ponds and permanent marshy areas, on the east bank. Most of the area dries out completely in the summer but a few of the deeper pools and meandering watercourses remain wet and provide some breeding habitat for waterfowl. The region is a very important wintering area for geese, teal, cranes and ducks. The occasional bull shark periodically patrols the River.  

In two of several competing theories about the origins and location of the Garden of Eden the Karoon is presumed to be the Gihon River that is described in the Biblical book of Genesis. The strongest of these theories propounded by archeologist Juris Zarins places the Garden of Eden at the northern tip of the Persian Gulf, fed by the four rivers Tigris, Euphrates, Gihon Karoon and Pishon.  

The name of the river is derived from the mountain peak—Koohrang that serves as its source.  

One of the main attractions of the River is the White Bridge which stretches half a kilometer and was constructed in 1936. It is a suspension bridge and consists of two steel arcs and sits approximately 13 meters above the River. Several dams were built or are under construction on Karoon, some perhaps having more ill effects than benefits: 

• Shahid Abbaspour (Karoon I) Dam - Spans a crest length of 383 meters and a height of 203 meters. 

• Karoon II Dam - This dam would potentially be located in the Sussan Plain between Shahid Abbaspour and Karun-3, but the project is still under consideration because of fear of submerging archaeological sites.

• Karoon III Dam – Spans a crest length of 462 meters and a height of 205 meters. Experts of the Cultural Heritage and Tourism Organization were able to save the stone lions and tombstones in a graveyard in Khuzestan which were in danger of being submerged by the rising waters of the reservoir of the Karoon II Dam. The stone lions and tombstones of the Zir Pass in the Izeh region of Khuzestan Province, symbols of the bravery of Bakhtiari heroes 200 years ago, were finally transferred to a safe place. Prior to the construction of this dam 18 sites from the Epipaleolithic period (20,000-10,000 BCE) had been identified, including 13 caves and four rock shelters in the region. The river valley also has a large number of rock-carved reliefs, graves, ancient caves and other remains from the Elamite era (2700 BCE-645 BCE), many of which are now underwater. 

• Karoon IV Dam - Spans a crest length of 440 meters and a height of 230 meters. 

• Masjed Soleiman Dam - Spans a crest length of 480 meters and a height of 164 meters. 

• Gotvand Dam – Spans a crest length of 202 meters and a height of 27 meters.  

In 2003 the Shadravan Dyke Bridge on Karoon River, which had withstood the river’s heavy floods for years, was to be restored and reconstructed. The bridge was once 550 meters long and included 35 spans before, but due to negligence only parts of it and 30 of its spans existed, three of which had been completely restored. The Cultural Heritage Organization were trying to restore the bridge based on its Sassanian style.  

In 2009, an Italian team specializing in lighting design had been invited to bring sparkling nights back to Karoon River. The team headed by Piero Castiglioni was to work on designing luminaries and lighting systems alongside Karoon River and the numerous bridges over it, as well as the public parks in the city. 

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