The Helmand is the longest river in Afghanistan and the primary watershed for the endorheic Sistan Basin. It originates in the Sanglakh Range of the Hindu Kush mountains in the northeastern part of Maidan Wardak Province, where it is separated from the watershed of the Kabul River by the Unai Pass. The Helmand feeds into the Hamun Lake on the border of Afghanistan and Iran.
An endorheic basin is a drainage basin that normally retains water and allows no outflow to other, external bodies of water ; instead, the water drainage flows into permanent and seasonal lakes and swamps that equilibrate through evaporation. Endorheic basins are also called closed basins, terminal basins, and internal drainage systems.
Zabol is a city in the Central District of Zabol County, Sistan and Baluchestan province, Iran, serving as capital of both the county and the district. Zabol is near the border with Afghanistan. Referred to as Sistan until the late 1920s, the city was renamed Zabol by Reza Shah Pahlavi.
Nimruz or Nimroz is one of the 34 provinces of Afghanistan, located in the southwestern part of the country. It lies to the east of the Sistan and Baluchestan Province of Iran and north of Balochistan, Pakistan, also bordering the Afghan provinces of Farah and Helmand. It has a population of about 186,963 people. The province is divided into five districts, encompassing about 649 villages.
Lashkargāh, historically called Bost or Boost, is a city in southwestern Afghanistan and the capital of Helmand Province. It is located in Lashkargah District, where the Arghandab River merges into the Helmand River. The city has a population of 201,546 as of 2006. Lashkargah is linked by major roads with Kandahar to the east, Zaranj on the border with Iran to the west, and Farah and Herat to the north-west. It is mostly very arid and desolate. However, farming does exist around the Helmand and Arghandab rivers. Bost Airport is located on the east bank of the Helmand River, five miles north of the junction of the Helmand and Arghandab rivers. Because of the trading hubs, it is Afghanistan's second largest city in size, after Kabul and before Kandahar.
Lake Hāmūn, or the Hamoun Oasis, is a seasonal lake and wetlands in the endorheic Sīstān Basin in the Sistan region on the Afghanistan–Iran border. In Iran, it is also known as Hāmūn-e Helmand, Hāmūn-e Hīrmand, or Daryāche-ye Sīstān.
In geology, a depression is a landform sunken or depressed below the surrounding area. Depressions form by various mechanisms.
Drangiana or Zarangiana (Greek: Δραγγιανή, Drangianē; also attested in Old Western Iranian as 𐏀𐎼𐎣, Zraka or Zranka, was a historical region and administrative division of the Achaemenid Empire. This region comprises territory around Hamun Lake, wetlands in endorheic Sistan Basin on the Iran-Afghan border, and its primary watershed Helmand river in what is nowadays southwestern region of Afghanistan.
The Kajaki Dam is "an earth and rockfill embankment type dam" located on the Helmand River in the Kajaki District of Helmand Province in Afghanistan, about 161 km (100 mi) northwest of Kandahar. It has a hydroelectric power station, which is operated by the Helmand and Arghandab Valley Authority through the Ministry of Energy and Water.
Oshida or Mount Khwaja or Mount Khwajeh is a flat-topped black basalt hill rising up as an island in the middle of Lake Hamun, in the Iranian province of Sistan and Baluchestan.
The Sistan Basin is an inland endorheic basin encompassing large parts of southwestern Afghanistan and minor parts of southeastern Iran. It is one of the driest regions in the world and an area subject to prolonged droughts. Its watershed is a system of rivers flowing from the highlands of Afghanistan into freshwater lakes and marshes and then to its ultimate destination: Afghanistan's saline Godzareh depression, part of the extensive Sistan terminal basin. The Helmand River drains the basin's largest watershed, fed mainly by snowmelt from the mountains of Hindu Kush, but other rivers contribute also.
The Arghistan or Arghastan is a river in southern Afghanistan. It flows through Arghistan District and the provinces of Zabul and Kandahar. It is a tributary of the Dori River, a sub-tributary of the Helmand River. It flows for 280 kilometres (170 mi) and has a basin area of 20,219 square kilometres (7,807 sq mi).
An endorheic lake is a collection of water within an endorheic basin, or sink, with no evident outlet. Endorheic lakes are generally saline as a result of being unable to get rid of solutes left in the lake by evaporation. These lakes can be used as indicators of anthropogenic change, such as irrigation or climate change, in the areas surrounding them. Lakes with subsurface drainage are considered cryptorheic.
Hamun-e Jaz Murian is an inland basin or depression in southeast Iran, straddling the provinces of Kerman and Sistan-Baluchistan. The area of Hamoon and Jazmourian basin stretches to 69,600 square kilometers, with the western part of 35,600 square kilometers in Kerman province and the eastern part of 34,000 square kilometers in Sistan-Baluchestan province.
A hamun refers to inland desert lakes or marshlands, formed as natural seasonal reservoirs in areas adjoining the Helmand basin, found across eastern Iran, southern Afghanistan and western Pakistan. They form a critical link in the wildlife of the area, aquatic as well as avian and terrestrial.
The 120-day wind or wind of 120 days is a strong summer wind occurring from late May to late September in the east and southeast of the Iranian Plateau, particularly the Sistan Basin. It is so called because it lasts for four months. The typical wind speed is 30–40 kilometres per hour (19–25 mph) or less, but it can occasionally exceed 100–110 kilometres per hour (60–70 mph). Strong speeds are caused by the topography surrounding the region. The wind moves fairly consistently south-to-southeastward; along with the shamal, it is one of two well-known winds in Iran.
The Registan–North Pakistan sandy desert ecoregion covers the dry Sistan Basin of southern Afghanistan and portions of eastern Iran and southwest Pakistan. The Registan Desert is the eastern portion of the Sistan Basin. The region is almost entirely dry sandy desert, with some irrigated cropland along the rivers. There are some seasonal wetlands at the western terminus of the Helmand River into Hamun Lake. The region support five endemic species of reptiles.
Hamoon Jazmourian Basin is a Endorheic basin of Iran. In the classification of basins in Iran, it is considered a sub-basin and is a subset of the Central Plateau Basin. The area of this basin is 69,390 square kilometers and the rivers and canals of this basin enter Hamoon Jazmourian Lake.
