Where does our water come from?

WaterResearch Bhutan
4 days ago
11 min read

by Water Research Bhutan, 08 Apr 2026 waterresearchbhutan@gmail.com

How much do we know where does water in Bhutan rivers, streams and lakes come from? This article reviews recent research conducted in eastern Bhutan titled ‘Sources and pathways of spring flow and climate change effects in the Dungju Ri & Yude Ri catchments, Bhutan Himalaya’ which identified that 70 percentage of water in streams were from the precipitation. Does this apply across all Bhutan Himalayas from mountainous north to the southern foothills? Thus, this article was aimed to translate key finding of the study and discusses its relevance and implications to Bhutan’s water resource management explained in plain language with the aim to reach to grassroots level water resources managers and policy makers alike.

This question is crucial because it will shape how Bhutan allocates its resources to manage essential water supplies. Beyond satisfying the public's and environment's fundamental water needs, ambitious projects like establishing energy-intensive industries such as AI data centers and crypto mining, will demand substantial water use. Long-standing sectors driving GDP growth, including hydropower, agriculture, and tourism, also rely heavily on Bhutan's water resources. If Bhutan aims to become a superpower through these developments, we must confront tough questions about missing elements in our water management strategy. The process should begin by asking a simple yet vital principle: where does our water originate? Answering this will help identify the most effective ways to manage our water sources.

In the face of extreme climate events, adapting to periods of excess water also presents a serious challenge for Bhutan’s water resource management. According to the IPCC (2013), rising global temperatures are predicted to destabilise the Himalayan region by accelerating glacier retreat and thawing permafrost. This will contribute to more frequent landslides and rockfalls, while increased precipitation is expected to intensify runoff and shorten the gap between extreme flooding events in the Ganga and Brahmaputra basins including all river systems in Bhutan. These changes not only heighten the immediate risk of disasters such as Glacial Lake Outburst Floods but also create long-term instability in water availability for communities across the region.

While rain, ice, and snow are key drivers of river flow in the Himalayas—sustaining agriculture, hydropower, and ecosystems—our knowledge of how these elements contribute and vary over time remains limited. The region’s remoteness, restricted data sharing between countries, and insufficient understanding of water storage in steep landscapes hinder progress. As highlighted by Panwar (2020), a lack of long-term local data further complicates reliable predictions about recharge and water quality. Therefore, it is crucial for Bhutan to prioritise closing these data gaps within available resources to support effective water management.

Currently in Bhutan, a springshed management concept seems to be taken up as a ‘silver bullet’ to mitigate drying water sources which were mostly the spring water. Numerous sites across Bhutan were being identified as ‘recharge zones’, digging up trenches (infiltration pits) with the hope that all the water collected in those pits will feed into their streams/springs thus reviving the water sources. Further, too many shallow freshwater ‘lakes’ are also being revived from ‘drying’ mainly through removing weed growth and sediment deposits without much attention to overall catchment dynamics and almost limited scientific evidence on how those lakes are linked with subsurface flows. A specialist hydrologist is not required to connect water pockets in the catchment. What’s needed is clear technical guidance and dedicated stakeholder commitment to monitor water levels, quality, and ecology over few year years, enabling more informed decisions. An easy to collect data for such water source management can include: (1) gauging surface water level or bore water level (2) soil logs or test pits (3) site environmental history (4) precipitation records (5) monitor stress indicators in those catchments, and (6) any change in catchment that is impacting various components of site’s water balance. In summary as Panwar (2020) proposed the development and management plan for springs and streams in the Himalayas should include the following prerequisites: (i) quantification of recharge and discharge parameters (ii) quantification of the evolution of recharge area over time (iii) future predictive modelling of spring recharge area.

Tshewang (PhD scholar at Edith Cowan University) reported that though the springshed development approach has proven to be promising to rejuvenate springs in some Himalayan catchments, the major challenge lies in the accurate identification of the recharge areas. Due to the complexity of mountainous terrain, particularly, the groundwater flow system feeding springs is poorly understood, which makes the springshed approach difficult to scale up over larger areas. Thus, information on water sources of spring flow (such as groundwater, snowmelt, rainwater and soil water) and their pathways (local or regional) is urgently needed for an in-depth understanding of inner working of mountain aquifers system.

Tshewang and his team has applied the latest hydrogeochemical techniques in 2023-2024 to investigate springs and other source waters at various elevations at Yude Ri and Dungju Ri catchments, under Trashigang. In such hydrological research, tracers act like ‘scientific breadcrumbs’ that allow researchers to track the invisible journey of water as it moves through the environment. These markers can be natural tracers, such as unique ‘fingerprints’ of oxygen and hydrogen atoms already found in rain or snow, or artificial tracers, like safe, bright fluorescent dyes injected directly into the ground to see where they re-emerge. By measuring these substances in mountain springs or rivers, scientists can pinpoint whether the water originally came from melting glaciers, seasonal snow, or deep underground reservoirs. They also use these tools to calculate ‘water age’ determining how many years or even decades the water has been stored in the mountain's rocky interior before reaching a community's tap. Such "detective work" is essential for managing water resources, especially in regions like the Himalayas where understanding how different sources mix is the only way to predict future water availability.

The results from the study by Tshewang’s team pointed out that Spring flows primarily relied on precipitation (approximately 70 percentage from both direct precipitation and soil water), making them very sensitive to changes in precipitation. Significant contributions of shallow groundwater also indicated the vulnerability of spring flows to decreased snowfall relative to rainfall and the earlier onset of snowmelt, particularly for those located in the snow-rain transition zone (~2500 m). Such studies indicate that Bhutan priority should be to capture as much as possible the water that come in the form of precipitation. Numerous examples including nature-based solutions and engineered storage could be a short-term to long-term solutions but in long-term exploring more resilient mitigation options are critical to ensure water security.

Nevertheless, the main takeaway from this article is that every solution should rely on data gathered through scientific methods. The research by Tshewang and team is just one example; similar hydrogeological studies need to be the basis of decision making in terms of water management for all types of water resources explorations which in long-term can be costly to mitigate errors. Some key examples of effective water resource management can address challenges and opportunities related to:

Springshed management without proper robust data on linkage with recharge zone and the discharge zone. Proper identification of the recharge areas is crucial for the protection and implementation of springshed development strategies. Just assuming headwater regions acting as a recharging area in highly diverse geological setting like Bhutan Himalayas makes success rate of reviving drying streams very challenging,
Extraction of groundwater sources with limited hydrogeological information. Where does the bore draw water from and what are risks and opportunities? Damage and risk of contamination to groundwater can be costly and near impossible to remediate any damage. Or worse, what happens if we have been draining too much water and suddenly the systems the aquifer is exposed to air which they would trigger complex chemical reactions which often leads to increasing water acidity and then leaching toxic heavy metals (example Arsenic) which are common issues in Indian plains neighbouring Bhutan foothills. For instance, what groundwater management plan has been implemented for the newly established production wells installed a year ago in the centre of the Samtse industrial zone? and,
Sustainability of numerous mini-hydro power plants planned based on limited hydrogeological data or how do we mitigate hydrological risk to hydropower stations - as limitations was laid bare from major risk of floods to hydropower dams in 2025. Similarly, when developing key infrastructure near major bodies of water, it is essential to conduct thorough health and safety risk assessments, particularly hydrogeological studies. This approach could help reduce the number of bridges that are overrun by rising rivers during every monsoon season!

The article is published based on personal experiences and observations by a group of water researchers from Bhutan www.waterresearchbhutan.org

The article was also published in the National Newspaper of Bhutan (Kuensel) on 08 April 2026 Search result for: Where does our water come from?

substantial water use. Long-

standing sectors driving GDP

growth, including hydropower,

agriculture, and tourism, also

rely heavily on Bhutan’s water

resources. If Bhutan aims to

become a superpower through

these developments, we must

confront tough questions about

missing elements in our water

management strategy. The

process should begin by ask

ing a simple yet vital principle:

where does our water origi

nate? Answering this will help

identify the most effective ways

to manage our water sources.

In the face of extreme

climate events, adapting to

periods of excess water also

presents a serious challenge

for Bhutan’s water resource

management. According to

the IPCC (2013), rising global

temperatures are predicted to

destabilise the Himalayan re

gion by accelerating glacier re

treat and thawing permafrost.

This will contribute to more fre

quent landslides and rockfalls,

while increased precipitation

is expected to intensify runoff

and shorten the gap between

extreme flooding events in the

Ganga and Brahmaputra ba

sins including all river systems

in Bhutan. These changes not