A New Perspective: From a Single Engineering Project to a Basin-Wide Hydrological System
NGÔ THẾ VINH
Introduction: Two years after the groundbreaking ceremony on 5 August 2024, construction of the Funan Techo Canal continues in phased sections, while the approximately 180-kilometer canal remains far from completion. This article argues that the project should not be viewed merely as an inland navigation canal. Rather, it represents a multi-purpose water management system whose long-term operation may alter flood dynamics, sediment transport, and saline intrusion throughout the Lower Mekong Basin, particularly in Vietnam's Mekong Delta. The author further contends that the project raises serious questions regarding compliance with Article 5 of the 1995 Mekong Agreement. Cambodia classified the Funan Techo Canal as a project located on a tributary, thereby submitting it only under the Notification procedure instead of the mandatory Prior Consultation process required by the Procedures for Notification, Prior Consultation and Agreement (PNPCA). In reality, however, the canal is designed to draw water directly from both the Mekong River and the Bassac River, the two principal distributaries of the Lower Mekong, before discharging into the Gulf of Thailand. From this perspective, the project constitutes an inter-basin water diversion with potential transboundary implications extending beyond Cambodia's national territory. Avoiding the obligations of Article 5 weakens not only the institutional authority of the Mekong River Commission (MRC) but also risks establishing a precedent whereby future basin-wide projects could circumvent the cooperative framework established under the 1995 Mekong Agreement. Prime Minister Hun Manet has described the canal as both a birthday gift to his father, former Prime Minister Hun Sen, and as a new national legacy of the Khmer Kingdom. Cambodian officials have even compared the project to China's historic Grand Canal. Yet the larger questions remain unresolved. What economic and environmental costs will ultimately be borne by the Cambodian people? How might the project reshape Cambodia's relationship with Vietnam? And what consequences could emerge for the ecological future of the Lower Mekong Basin? This article therefore calls for a fundamental shift in perspective: away from viewing the Funan Techo Canal as an isolated engineering work, toward recognizing it as one component of an interconnected hydrological system. Such a perspective requires Cambodia to comply fully with Article 5 of the Mekong Agreement, disclose complete project data, and conduct comprehensive transboundary environmental impact assessments before the canal enters full operation.
Figure 1: Groundbreaking Ceremony for Section II of the Funan Techo Canal Project, held on 11 April 2026 in Borei Chulsar District, Takeo Province. The ceremony was presided over by Prime Minister Hun Manet, accompanied by Chinese Ambassador Wang Wenbin. Seated in the front row on the red carpet, from left to right, are the Chinese Ambassador to Cambodia, Prime Minister Hun Manet, and Deputy Prime Minister Sun Chanthol, Vice Chairman of the Council for the Development of Cambodia (CDC), who oversees national infrastructure and investment. Source: Agence Kampuchea Presse (AKP)
Developments Since the Groundbreaking Ceremony: Progress and Persistent Questions
One of the questions most frequently raised by readers is straightforward:
What is the current status of Cambodia's Funan Techo Canal Project?
This question is particularly timely because two years have now passed since the official groundbreaking ceremony of 5 August 2024, an event staged on an unprecedented national scale. The canal was presented as a flagship megaproject, a symbol of Cambodian national pride, and a legacy closely associated with the Hun family's political leadership. At that time, the Cambodian government confidently announced that the canal would be completed and become operational by 2028.
Figure 2: The groundbreaking ceremony of the Funan Techo Canal at the small village of Prek Takeo, Kien Svay District, Kandal Province, on 5 August 2024, coinciding with Hun Sen's birthday. The ceremony was chaired by his son, Prime Minister Hun Manet. Behind the ceremonial stage stood a giant Khmer-language banner proclaiming: "We Support the Funan Techo Canal." This location marks the beginning of Section I, a canal segment extending more than 20 kilometers, drawing water directly from the Lower Mekong River, upstream of Vietnam's Mekong Delta. Source: Khmer Times, 5 August 2024.
Figure 3: Map of the Funan Techo Canal Project. The canal (red line) diverts water from both distributaries of the Lower Mekong: the Lower Mekong River (light blue), which later becomes Vietnam's Tiền River, and the Bassac River (dark blue), which becomes the Hậu River downstream in the Mekong Delta. Source: Radio Free Asia (RFA)
As of August 2026, two years after the commencement of Section I, it has become evident that the Funan Techo Canal remains in the stage of phased construction, rather than full-scale excavation along its planned 180-kilometeralignment. The available evidence suggests that the project has yet to enter comprehensive construction across the entire route originally envisioned. Based on its current pace, it is increasingly likely that this ambitious undertaking will require substantially more time than initially projected before reaching completion.
Key Implementation Milestones During the First Two Years
Over the past two years, the project’s development can be summarized as follows:
- Following the groundbreaking ceremony on 5 August 2024, Reuters reported that by the end of 2024, there had been virtually no significant construction activity at the ceremony site, while the arrangements for securing financing from the Chinese side remained unclear.
- During 2025, Cambodia and China reached agreements on financing and the BOT model (Build-Operate-Transfer), while also carrying out boundary marking, surveying, and logistical preparations. In the initial phase, the Phnom Penh authorities indicated that a Chinese company might finance the entire project. Subsequently, the investment structure was revised, with Cambodian investors expected to hold 51% and the Chinese side 49%.
- A major turning point came in April 2025, during Chinese President Xi Jinping’s visit to Cambodia, when the two sides signed an agreement to develop a 151.6-kilometer canal section, valued at approximately US$1.2 billion. Prime Minister Hun Manet stated at the time that this infrastructure project was significant for Cambodia’s economic sovereignty, logistics capacity, and long-term national development.
- By early 2026, some residential areas along the canal alignment had not yet been cleared and remained subject to negotiations over land compensation. In addition, China provided a US$400 million concessional loan to finance the construction of navigation locks, irrigation systems, and bridges crossing the canal.
- On 11 April 2026, four months ago, Cambodia held the groundbreaking ceremony for Section II of the project in Borei Chulsar District, Takeo Province. Prime Minister Hun Manet presided over the ceremony together with Chinese Ambassador to Cambodia Wang Wenbin. The investor and contractor are a Cambodian-Chinese joint venture, with the Chinese state-owned China Communications Construction Company (CCCC) playing a major role. This is the largest section of the entire project.
Figure 4: Prime Minister Hun Manet and Chinese Ambassador to Cambodia Wang Wenbin attend the groundbreaking ceremony for Section II of the Funan Techo Canal Project, 11 April 2026. Source: Agence Kampuchea Presse (AKP)
- Cambodia has begun implementing Section II of the Funan Techo Integrated Water Resources Management (IWRM) Project. This section is approximately 151.6 kilometers long, connecting Kandal Province through Takeo and Kampot provinces to the sea at Kep. This demonstrates that the project has not been cancelled but is proceeding in phases, with the stated objective of completing the entire megaproject by 2028. [Sic]
- Section I, by contrast, is only approximately 26 kilometers long. It begins at a branch of the Upper Mekong River in Kien Svay District, Kandal Province, where the original groundbreaking ceremony was held on 5 August 2024. Cambodian Deputy Prime Minister Sun Chanthol reported that boundary identification and map verification for the initial section had achieved some progress. Authorities had marked 155 land boundaries and allocated nearly US$71 million for compensation in this area.
- The Funan Techo Canal Project (FTC) is intended not merely as an inland waterway connecting Cambodia’s river system with the Gulf of Thailand. It is also expected to provide water for agricultural production and aquaculture, promote the development of economic zones, logistics centers, ports, and expand tourism activities in the localities along the canal corridor.
According to information released by Cambodia’s Ministry of Information on 27 May 2026, Section II has a total investment of approximately US$1.17 billion and an expected construction period of 36 months, or three years, beginning with the groundbreaking in April 2026. This would mean completion in April 2029.
Figure 5. Graphic representation of the Funan Techo Canal released by Cambodia’s Ministry of Public Works and Transport. [Image source: Royal Government of Cambodia]
Why the 2028 Completion Target Is Difficult to Achieve
The stated objective of completing the entire project by 2028 therefore appears entirely unrealistic. There are at least three major reasons:
1. The enormous scale of construction
The canal is approximately 180 kilometers long, 80–100 meters wide, and about 5.4 meters deep, and will require:
- numerous bridges;
- navigation locks;
- water-regulation structures;
- ports;
- logistics infrastructure; and
- the relocation and clearance of residential areas and other sites along the right-of-way.
2. Financing
Although Beijing has reiterated its commitment to supporting completion of the project, the scale of investment and financing mechanism have already been revised several times over the past two years.
3. Technical and environmental issues
Experts from a number of research institutions, including the Stimson Center and the Mekong River Commission (MRC), continue to point to the lack of transparent data concerning:
- the volume of water to be diverted from the Mekong River;
- impacts on the Mekong Delta;
- the operating regime of the navigation locks;
- impacts on the natural flood regime; and
- sediment loss.
From a purely construction-engineering perspective, completing a 180-kilometer canal within approximately three years (2026–2029) would already be a formidable undertaking.
Based on Cambodia’s own experience with major infrastructure projects, the Phnom Penh–Sihanoukville Expressway, which is narrower, shallower in construction requirements, and does not involve complex navigation locks, took three years and six months to complete.
A scenario anticipated by many experts is therefore that the project may have to be delayed until 2030 or beyond, or that different sections will be completed sequentially and subsequently connected before the entire canal is brought into full operation.
Three Major Questions Concerning Impacts on the Mekong Delta
Because of growing concern over the canal’s potential impacts on the Mekong Delta, three questions have become the focus of the most intense debate:
- Will the Funan Techo Canal actually reduce the volume of Mekong River water flowing into Vietnam?
- To what extent will it reduce the sediment supply reaching the Mekong Delta?
- How significant will the canal’s impact be compared with the impacts of the 12 hydropower dams on the Mekong mainstream?
Figure 6: Underwater clearance of unexploded ordnance (UXO / Unexploded Ordnance) to ensure safety during construction of the Funan Techo Canal.
[Khmer Times, 26 February 2025]
The Impacts Must Be Viewed Within the Entire Mekong River System
CONCERNS ABOUT THE IMPACTS ON THE MEKONG DELTA
The Funan Techo Canal is not merely a stand-alone transportation project. It will constitute a Multi-Purpose Integrated Project affecting an already fragile ecosystem within the Mekong River Basin.
The question, therefore, is not simply: “Will this canal cause the Mekong Delta to dry out?” Rather, the more important question is: “To what extent will it interact synergistically with the impacts already produced by the chain of upstream dams?”
There are three issues that need to be considered separately:
1. Water Discharge: There Will Be an Impact, but It May Not Be the Greatest One
From a hydrological perspective, Cambodia argues that the amount of water required for navigation will be only about 5 m³/s, a very small volume compared with the discharge of the Mekong River, and therefore that the impact will be negligible.
However, many experts are convinced that the Funan Techo Canal is not simply a navigation canal.
Recent Cambodian documents and official statements indicate that the project is also intended to:
- irrigate approximately 300,000 hectares of agricultural land;
- provide water for domestic use;
- support urban development; and
- facilitate the development of industrial zones along both sides of the canal.
Thus, the amount of water withdrawn from the Mekong–Bassac river system would be substantially greater than the initial figure of 5 m³/s cited for navigation.
This is also an issue that the Stimson Center, the Mekong River Commission (MRC), and environmental advocates have argued needs to be clarified through comprehensive feasibility studies.
2. The Greatest Concern May Not Be “Loss of Water,” but “Loss of Floods”
This is a point that has received relatively little emphasis in the Vietnamese media.
Researchers at the Stimson Center have suggested that the canal, with its elevated embankments, could alter the pathways through which wet-season floodwaters spread.
For the Mekong Delta, floods are not simply natural disasters. They also bring essential ecological benefits: sediment, nutrients, fish larvae and juveniles, freshwater, and the natural capacity to flush saltwater from the delta.
If floodwaters are retained or diverted upstream in Cambodia, provinces in the upper reaches of the Vietnamese Mekong Delta, such as An Giang, Dong Thap, and Kien Giang, could receive less floodwater.
This could lead to:
- declining natural fishery production;
- reduced sediment deposition; and
- weakened natural protection against saltwater intrusion.
In other words, “loss of water, loss of floods” may become the greatest risk.
3. Saltwater Intrusion
The Mekong Delta is already under four major pressures:
- sea-level rise;
- groundwater extraction;
- declining dry-season flows; and
- saltwater intrusion.
If the Funan Techo Canal withdraws additional water during the dry season, even if only by a few percent, it could potentially result in:
- saltwater penetrating farther inland;
- longer periods of salinity intrusion;
- greater damage to rice-growing areas and fruit orchards; and
- reduced sediment delivery to the delta.
To date, no international model has demonstrated with precision the magnitude of these potential impacts, partly because Cambodia has not yet released a Strategic Environmental Assessment (SEA) Report, detailed engineering plans, and operating procedures that would allow independent scientists to fully assess and verify the consequences.
In my view, the Mekong Delta is currently being affected simultaneously by four major variables:
Major factor | Relative impact |
Upstream Mekong hydropower dam cascade | ★★★★★ |
Climate change and El Niño | ★★★★★ |
Groundwater extraction and land subsidence in the Mekong Delta | ★★★★☆ |
Funan Techo Canal | ★★★☆☆ (not yet quantifiable) |
In other words, Funan Techo may not be the “only threat,” but it could become “the straw that breaks the camel’s back.”
This assessment is also increasingly appearing in Mekong research circles.
A Broader Perspective Is Needed
After many years of following developments in the Mekong, I have come to believe that a broader perspective is urgently needed.
- Around 2000, when I published Cửu Long Cạn Dòng, Biển Đông Dậy Sóng (The Mekong, Drying Up and the South China Sea in Turmoil), attention was focused primarily on the upstream mainstream hydropower dams on the Mekong.
- In the years that followed, particularly from 2023 onward, I, together with many other experts, began to pay greater attention to “new variables.” The Funan Techo Canal is one of them, because its implications extend beyond water volume. It could potentially alter the hydrological patterns of the Cambodian floodplain, the Mekong Delta, and the Tonle Sap, the freshwater lake regarded as one of the largest such lakes in the world. I have repeatedly described Tonle Sap as the “ecological heart” of the entire Lower Mekong Basin.
In my view, our concern today can no longer be limited to the upstream mainstream dams. We must broaden the framework to encompass five major propositions.
I. First Warning: “Hydropower Dams Are Transforming the Mekong from a Natural River into a Regulated River”
When I wrote the two books Cửu Long Cạn Dòng, Biển Đông Dậy Sóng and Mekong Dòng Sông Nghẽn Mạch (Mekong: The Occluding River), many people still viewed dams primarily as structures that stored and released water for electricity generation.
But by 2026, our assessment has changed. We can now see that:
- the seasonal flow regime has been “flattened”
- flood peaks have become lower;
- anomalous water releases have increasingly occurred during the dry season; and
- the biological rhythms of the entire basin have been altered.
Today, many hydrologists are increasingly reluctant to describe the downstream Mekong flow regime simply as a “natural hydrograph.”
II. Second Warning: “Sediment Is the Most Precious Asset”
Twenty years ago, much of the attention was focused on the quantity of water.
Today, the research community increasingly recognizes that:
The Mekong will not necessarily die first from lack of water. It may die from the loss of sediment.
According to numerous studies, the sediment reaching the delta has declined dramatically because upstream reservoirs and dams retain a large proportion of the river’s sediment load.
This contributes to:
- increased riverbank and coastal erosion; and
- the gradual loss of the delta’s natural fertility.
III. Third Warning: The Delta May Sink Faster Than Sea Level Rises
When my books were first published, public discussion often centered on the idea:
“Climate change will submerge the delta.”
Today, geologists increasingly emphasize another reality:
The delta is sinking under its own weight and human pressures, in some areas faster than sea level is rising.
The principal causes include:
- groundwater extraction;
- insufficient sediment replenishment; and
- natural and human-induced compaction of the deltaic sediments.
In other words:
The Mekong Delta is being attacked from below by land subsidence and from outside by sea-level rise.
This is something that few people fully appreciated 15–20 years ago.
IV. Fourth Warning: Funan Techo Is Not Merely “A Canal”
This is the point that, in my view, needs to be updated from the perspective of when the earlier books were written.
If, in 2017 or 2020, someone had asked me:
“What is the greatest threat?”
I would have answered:
“The 11 mainstream hydropower dams.”
But by 2026, the answer must be different and the perspective broader:
“The greatest threat is the absence of an integrated water-regulation system for the entire Lower Mekong Basin.”
And Funan Techo must be regarded as a new link in that system.
One particularly clear and noteworthy development is that the objectives of the Funan Techo project appear to have expanded beyond navigation toward irrigation, with potential implications for water regulation and agricultural economic development along the canal corridor.
At the same time, many experts have argued that the canal’s embankments and navigation-lock system could alter the natural flood regime in Cambodia and transmit impacts downstream to the Mekong Delta if operated on a large scale.
In other words:
Funan Techo is not merely a navigation canal. It is a water-management infrastructure project.
That distinction is highly significant and differs substantially from the way the Phnom Penh authorities have publicly characterized the project.
V. Fifth Warning: The Greatest Crisis Is a “Water Governance Crisis”
This is becoming increasingly evident with the passage of time.
Today, the issue is no longer simply:
- China builds dams in the Upper Basin;
- Laos builds dams in the Lower Basin; and
- Cambodia excavates the Funan Techo Canal.
The deeper issue is this:
There is currently no sufficiently strong basin-wide governance mechanism capable of requiring all countries to share data, conduct meaningful consultation, and assess transboundary impacts.
Even in the case of Funan Techo, the Mekong River Commission (MRC) has indicated that it has so far received only basic information and continues to seek comprehensive feasibility studies and technical documentation from Cambodia in order to assess the project’s impacts on the basin as a whole.
This is precisely the “governance impasse” that many experts are now emphasizing.
I have long hoped to write a third book, tentatively titled:
Mekong After the Dams: The Era of Water-Regulation Infrastructure
It would complete a three-volume Mekong trilogy.
The new book would examine four emerging variables:
- The Funan Techo Canal as an additional water-regulation infrastructure project, rather than merely a transportation route;
- Climate change, with increasingly frequent droughts and climate extremes;
- Delta subsidence, now regarded as one of the most urgent threats facing the Mekong Delta; and
- Basin governance, emphasizing that the Mekong crisis today is no longer a story of individual dams or individual canals, but of an entire system suffering from inadequate coordination.
A Shift in the Way We Study the Mekong
A fundamental shift in Mekong research is needed across three stages of development over the past three decades:
Stage I: 1995–2005
The focus was primarily on Chinese hydropower dams in the Upper Mekong Basin.
Stage II: 2005–2015
The focus expanded to include mainstream dams and major tributary projects in Laos and Cambodia.
Stage III: 2015–2026
The entire basin increasingly needs to be understood as an interconnected system, in which hydropower dams, climate change, groundwater extraction, land subsidence, sand mining, and now the Funan Techo Canal interact and reinforce one another.
This is the approach most appropriate for the years ahead.
What to Watch Between 2024 and 2030
Having followed the development of the Funan Techo project since 2024, I believe that from now through 2030, a number of critical milestones and turning points will deserve close observation:
- Will actual construction progress keep pace with the announced schedule?
- Will Cambodia release comprehensive hydrological data and operational information?
- How will the assessments of the Mekong River Commission (MRC), the international scientific community, and the Vietnamese government evolve?
- And, most importantly, will the impacts actually measured in the Tonle Sap region and the Mekong Delta correspond to the projections currently being made?
These questions will determine whether Funan Techo ultimately remains primarily a transportation project, or becomes something much larger: a new water-regulation system embedded within the already stressed hydrological architecture of the Lower Mekong Basin.
This Is the Most Appropriate Approach for the Years Ahead
Given the continuous monitoring of the Funan Techo Canal Project from 2024 to the present, and certainly from now until 2030, there will be many important milestones and turning points:
- Whether the actual construction progress can keep pace with the announced schedule;
- Whether Cambodia will fully disclose hydrological data and operational procedures;
- How the assessments by the Mekong River Commission (MRC), the international scientific community, and the Vietnamese government will evolve;
- And most importantly, whether the measurable impacts observed in Tonlé Sap Lake and the Mekong Delta will correspond with current predictions.
Tonlé Sap Lake in the Context of Hydrological Decline
A Lake That Has Continuously Deteriorated
The question is: By the 2026 Wet Season, where has the Mekong River water gone?
According to the Mekong Dam Monitor (7–20 July 2026), the annual flood season arrived more than six weeks late. The Tonlé Sap River, which normally experiences a powerful seasonal reversal of flow into Tonlé Sap Lake, showed an unusually weakened reversal this year.
The abnormal behavior of the Mekong Basin during this year's wet season resulted in only approximately 4.03 billion cubic meters (m³) of reverse-flow water, far below the historical average of more than 11 billion cubic meters (m³).
The extraordinary phenomenon of the Tonlé Sap River’s annual reverse flow during the Wet Season is a life-sustaining mechanism that nourishes Tonlé Sap Lake, the world’s largest freshwater fishery lake. However, upstream hydropower dams, particularly those in China, have been storing enormous volumes of water in their reservoirs, weakening the natural flow regime of the Mekong River. During only the past week, major Chinese reservoirs retained approximately 2 billion m³ of water.
Monitoring of seasonal flooding shows that the flooded area decreased from approximately 7,400 km² at the end of June to only 6,000 km² in early July, contrary to the normal pattern, when the flooded area should expand rapidly during this period.
During the first week of July 2026, the total amount of water retained by major dams throughout the entire Mekong Basin reached 2.44 billion m³. Among them, the Xiaowan and Nuozhadu dams in China, and the Sirindhorn Dam in Thailand, had the greatest impacts. Water levels along the Mekong River on the Thailand–Laos border remained approximately 2 meters below normal levels.
Unanswered Questions and Directions for Future Research
After seven articles forming a kind of “chronicle of the Funan Techo Canal Project,” this eighth article continues by raising several unanswered questions:
- When will Cambodia fully release the Feasibility Study?
- When will Cambodia publicly disclose the complete hydraulic modeling data and operational procedures?
- When will the Mekong River Commission (MRC) conduct a comprehensive assessment of transboundary impacts?
- What monitoring systems will be used to track changes in the ecological “heart” of Tonlé Sap Lake and the Mekong Delta?
These are the questions that this eighth article continues to raise, opening an urgently needed direction for future research.
We need to continue monitoring and updating the latest Mekong research through:
- Synthesizing the newest scientific studies;
- Comparing data from year to year;
- Analyzing maps, satellite imagery, and hydrological records;
- Constructing a comprehensive timeline of the entire Mekong Basin from the 1950s to the present.
The Mekong, a river that has sustained more than 70 million people throughout its basin, has always faced challenges and transformations of historic significance. Let us protect environmental justice for them.
NGÔ THẾ VINH
05 August 2024 – 05 August 2026
Related Articles:
1/ From the Khmer Funan Empire to the Historic Funan Techo Canal of the Kingdom of Cambodia.
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2/ Funan: The Historic Canal and the Project's Implementation Steps under the Father-and-Son Dynasties.
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3/ RFA Interview with Dr. Ngo The Vinh on the Funan Canal and the Mekong Delta.
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4/ The Funan Techo Canal Project: Vietnam–Cambodia Responses, A Case of “Different Beds, Same Dream.”
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5/ For Whom the Bell Tolls: August 5, 2024 — The Groundbreaking Ceremony of the Funan Techo Canal.
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6/ The Funan Techo Canal after the Earthquake of 05.08.2024: An Ending to a Beginning, Yet Still Time to Seek Justice for the 20 Million Residents of the Mekong Delta.
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7/ An Update on the Progress of the Funan Techo Canal Project from May 2023 to December 2025.
