Amu Darya and Kabul river basins major sources of water for Afghanistan: Study

A new study has revealed interesting insights about water in Afghanistan, which has suffered recurrent droughts since the 1990s, during which it has also experienced some of its worst wars.

The researchers divided Afghanistan into five river basins and found that two of the five are the major water sources for the country.

Even more interestingly, it found that 28.6 billion cubic metres (BCM) of the country’s water is generated in areas outside it.

“This information is crucial for long term planning for water resources and agricultural development,” the authors wrote.

Five basins

The researchers divided the country into five river basins for the purpose of the study:

• Harirod-Murghab River Basin (HMRB)
• Helmand River Basin (HRB)
• Kabul River Basin (KRB)
• Northern River Basin (NRB)
• Panj-Amu River Basin (PARB)

Four of these are transboundary basins flowing to neighbouring countries except the Northern Basin, the study noted.

The PARB is mainly formed by the Amu Darya — whose headstream is the Panj. Known as Oxus in antiquity, the Amu Darya flows into Central Asia and ends in the now-dead Aral Sea.

“The Amu river originates in the glaciers of the Pamirs and drains an area of approximately 241,000 sq km in the north-eastern and northern parts of Afghanistan,” the study said.

The scientists added that the PARB is Afghanistan’s second-largest, comprising 14.3 per cent of the country. It also overlaps into neighbouring Tajikistan:

The water yield from Panj-Amu basin is about 42.7 BCM comprising 16 BCM within Afghanistan and 26.7 BCM in the neighbouring Tajikistan, mostly from glacier melting in the Hindu-Kush mountains. It is important to note that the water yield in the Panj-Amu basin largely depends on flow from neighbouring Tajikistan.

At 51 per cent, the HRB is the largest river basin in Afghanistan. “The Helmand is the longest and biggest river in southwest Afghanistan. It originates in the mountain range about 80 km west of Kabul and travels 1,150 km before draining into seasonal lakes along the Afghanistan-Iran border,” the study noted.

Mean annual water yield in the period of 2008 to 2020 in the basin is about 11.7 BCM (25 per cent of the total water yield).

The water yield from the HMRB is relatively small at about 6.5 BCM, which is 14 per cent of total water yield within Afghanistan:

The Harirod and Murghab rivers form the drainage system in the north-western region. The Harirod river originates in the mountain range of central Afghanistan and flows westward across the Herat Valley. It is the main source of irrigation water for the agriculture along the fertile lands of the valley.

The Shirin, Sarepul and Balkh are the large rivers in the NRB. “Northern basin occupies 74,688 sq km of land (11.6 per cent of total land) and produces 5.1 BCM water (11 per cent) which is the lowest among the five river basins,” the study said.

The last basin, the KRB, is mainly formed by the Kabul river. “The Kabul river is the largest drainage system in the south-eastern region. It originates in the Paghman Range and flows eastward to join the Indus river in Pakistan,” the researchers said.

The KRB covers 11 per cent of Afghanistan and produces 6.9 BCM water within Afghanistan and 1.9 BCM in Pakistan, primarily through the Kunar river from melting glaciers and snow of the Hindu Kush mountains.

The researchers said there were reasons for the PARB and KRB having more water.

“Yields are higher in the Kabul and Panj-Amu Basin compared to other basins primarily due to higher precipitation and partly due to low evapotranspiration loss,” they said.

They also observed that water yield was maximum during the spring months.

“Compared to the inter-annual flow, water yield between months varies significantly with about 60 to 70 per cent occurring between March and June. This indicates the need to find alternative sources for irrigation and domestic use during the dry period,” according to the researchers.

The findings assume importance as Afghanistan, on the borders of Central and South Asia, is suffering from extreme water stress.

“While every continent is experiencing water scarcity to some extent, the problems of scarcity are especially acute in Central Asia where approximately 80 per cent of the population experiences water stress, and about 50 per cent of the population suffers from water shortages. With the growing population water demand in Afghanistan likely to increase in the future, at the same time, climate change is having, and will continue to have, global, regional, and local impacts on water availability,” the study noted.

Large scale water yield assessment for sparsely monitored river basins: A case study for Afghanistan was published on April 16, 2024 in Plos Water.

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