Monday, March 4, 2013

Rivers of Armenia

Armenia is not rich in water resources despite having quite a network of rivers – they are rather small. All in all there are more than three hundred rivers of 10 km and longer. Some of them cut deep gorges and canyons in steep stony rocks. The majority of rivers in Armenia are the inflows of the river Araks – one of the largest rivers in the Caucasus flowing across entire Georgia and running into the river Kura on the territory of Azerbaijan. The big inflows of Araks on the territory of Armenia are the Akhuryan, the Kasagh, the Razdan, the Arpa and the Vorotan. The rivers Debed, Agstev and Akhum are the right inflows of the Kura running into the Caspian Sea. Some Armenian rivers belong to Lake Sevan basin.
The rivers are fed with thawed, rain and subsoil waters. In spring the rivers become rapid and deep. And in the middle of summer the rivers get shallow and in the autumn their levels will rise at the expense of rain water.

The Longest Rivers:

Araks – on the territory of Armenia - 158 km (total length - 1,072 km)
Akhuryan - 186 km
Vorotan – on the territory of Armenia - 119 km (total length - 179 km)
Debed – on the territory of Armenia - 152 km (total length - 178 km)
Razdan - 141 km
Agstev – on the territory of Armenia - 99 km (total length - 133 km)
Water resources are rivers, lakes and underground water (see Figure 2). Annually rivers bring in six billion m3 of water. An appropriate use of this amount would suffice to irrigate the low and foothill regions. The northern river network drains to the Caspian sea and includes about 450 rivers and streams extending for more than 10 km. Rivers of Southern Armenia drain to the basin of the River Araks (about 74 percent of the river net).

Maximum floods occur in May, by September they become less. Most rivers in their lower stretches are subject to mudflows, and sudden and intense floods especially in spring. These are accompanied by the washing down of a huge amount of mud and stones. Because of the fast flow rivers do not freeze. Seasonal distribution of river flow is uneven. Thus, the flow in the cold half of the year from September to February is only 25 percent of the total, while that in the warmer half is 75 percent. The flow in the warm season is distinguished by a substantial variability.
The biggest and deepest river is the boundary River Araks which stretches through Armenia for only 200 km. Its major tributaries in Armenia are the Akhuryan, Hrazdan, Azat, Vedi, Vorotan, Vokhchi, Megri, etc. The River Sevjur is remarkable for being mainly fed by underground water. The rivers of the Koor basin have their source in the northern, damper part of the country and are consequently deeper. One of the largest tributaries of the River Koor in the Republic is the River Debed formed by the joining of two rivers, Dsoraget and Pambak.
There are more than 100 minor mountain lakes, most of them above 2,000 m, that typically are used for watering pastures. Lake Sevan is of national significance (about 35 billion m3), its water being intensively used for irrigation and energy generation. Among minor lakes, the following: Arpa, Akna, Lori, and Cars have been used recently not only for irrigation but also for fish farming.
Swamp and marshlands are mainly in the north-west of the Lori plateau, Shurabad basin, Masrin and Ararat valleys; most have already been drained and are used for agriculture. In the north of Armenia swampiness is favoured by high rainfall, a flat land surface and the presence of underground water, while in the south it is favoured by the ancient river-beds of the River Araks..
The Aras (also known as Araks, Arax, Araxi, Araxes, Araz, or Yeraskh; Armenian: Արաքս or Երասխ (Araqs or Erasx), Azerbaijani: Araz, Persian: ارس‎ (Aras), Turkish: Aras, Kurdish: Aras or Erez; Russian: Аракс; Latin: Aboras), is a river located in and along the countries of Turkey, Armenia, Azerbaijan, and Iran. Its total length is 1,072 kilometers (666 mi). Given its length and a basin that covers an area of 102,000 km², it is one of the largest rivers of the Caucasus.