Yangyel Lhaden

The Hindu Kush Himalayan (HKH) region is experiencing a significant decline in snow persistence, affecting the water security of millions living within the HKH region and billions living downstream.

According to the International Centre for Integrated Mountain Development (ICIMOD) Snow Update Report 2024, the region experienced nearly a 20 percent decline in average snow cover between November 2023 and April 2024, compared to historical records spanning the last two decades. Bhutan is within the HKH region.

Snow persistence refers to the duration of time that snow remains on the ground before melting away. The duration snow remains on the ground is important for recharging the water table to ensure the sustainability and continuity of the water supply.

One of the two river mouths for Bhutan’s rivers is in the Brahmaputra. In the Brahmaputra River basin, the current snow persistence is also notably below normal at 14.6 percent. It experienced the lowest seasonal snow persistence in 2021 when it dropped below average at 15.5 percent. The highest recorded snow persistence occurred in 2019, reaching 27.1 percent, according to the ICIMOD report.

In Bhutan, the drinking water supply primarily comes from springs and streams. A 2021 study by the Watershed Management Division, now the Department of Water, reported that, out of the 7,399 tapped water sources in the country, 69 have dried up, and 1,856 are in the process of drying up.

Out of the water sources, springs are the major sources of drinking water in the country, accounting for 67.6 percent, followed by streams at 25.7 percent, marshes at 2.7 percent, ponds at 2.3 percent, rivers at 1.1 percent, and lakes at 0.7 percent.

A Department of Water (DoW) official said that snow persistence, which was the lowest in two decades, was a critical issue. “There are various factors in recharging water sources and snow and rain are two major components along with good quality of water table maintained by a healthy forest.”

He said that the issue today was that there was either “too little or too much rain” and it had not snowed in the last three years in a way that allowed snow to stay on the ground to recharge water tables. He added, “There is rainfall, but it comes untimely and all at once, hindering the soil to soak in and recharge water tables but  it causes erosion and landslides instead.”

Reports of drinking and irrigation water shortages have been growing in recent years. The DoW is also receiving complaints of water shortage from communities and individuals.

In Thimphu, the Babesa and Olakha areas face acute water shortages during the lean season when two sources—Chamgang and Royal Thimphu College (RTC) area water sources—dry up. This year, the RTC water source decreased by 60 percent, and the Chamgang water source decreased by 70 percent in spring compared with the same time last year, affecting the timely water supply to residents.

The Thimphu Thromde has received approval to test the feasibility of borehole water from Thimchhu to meet the water needs of Babesa and Olakha.

To curb water shortages, especially for irrigation, the government has allowed water to be pumped from rivers, such as in Paro. “People are also drinking the river water pumped for irrigation when there is a shortage of water supply at homes,”the official said.

Although the country faces water shortages, Bhutan has one of the highest per capita water availability in the world. Official figures show that Bhutan generates about 70,500 million m³ of water annually, meaning each Bhutanese should ideally have access to about 94,500 m³ of water per person per year.

The official said that one of the problems with water availability for residents although we had the highest per capita water availability in the world was due to the rugged terrain and settlements at higher elevations. “This necessitates pumping water to reach these residents.”

Additionally, effective water resource management was crucial, as the issue sometimes lay not in water shortage but in water management problems, the official added.

The ICIMOD report emphasises the need for proactive steps, such as revising water management laws and improving regional collaboration, to bolster resilience against climate change effects. The report states that the reduction in snow persistence in the HKH serves as a stark warning rather than merely a scientific observation.