From Israeli to Indian aid in Cambodia: The Prek Thnot river basin’s hydraulic development paradigm

Overview: Cambodian Irrigation Issues

The entire Mekong Basin is undergoing a period of rapid social and environmental transformation, a large part of which is closely linked to decisions made over water resources development and management. States and non-state actors, both domestic and international, profit and non-profit agencies and institutions, are piling into this sector and competing for their share of the action, making for a highly contested and politicized arena. Often the prior development history and discourse surrounding current developments are overlooked in the headlong rush for constructing more hydraulic infrastructure.

“Water resources management” incorporates a capacious and inclusive umbrella of actors, where few are excluded but in some contexts not all are welcome to contribute as true “stakeholders”, particularly those in civil society that bring a critical eye to the development paradigm or deviate from dominant state-sanctioned narratives. Exclusion and silencing of diverse voices are standard tactics by those that hold the reins of power. After all, there are considerable vested interests at stake, both politically and economically, especially where individual projects can be valued in amounts that run into several billion US dollars.

While hydropower is considered controversial and attracts increasing amounts of critical scrutiny regionally, especially from international media and NGOs, the irrigation sector is considered more benign and end-user friendly, and thus far has largely escaped much critical scrutiny, even though it is often more likely to fail and have wider ecological implications than hydropower. And for a Mekong fish species, it is unlikely to question whether the wall of concrete blocking its migration path is built for irrigation or hydropower purposes, though it may be less likely to survive or thrive in the run-off from the agrichemical-laced water created by irrigation schemes. An irrigation scheme’s ecological footprint may often be far more extensive and profound than that of a hydropower project. Furthermore, there is emerging evidence to suggest that many, if not most, irrigation schemes in the Lower Mekong Basin are failing on both technical and socio-economic grounds to achieve anything like basic standards of sustainability or meet their original development goals.

The following is part one of a three article series that touches upon various issues related to the current state of irrigation and water resources development in Cambodia arose from reflections prompted by a recent field visit by the author. Each article focuses on a different river system or irrigation scheme that I visited on the ground in mid-March 2017 and covers various aspects of the water resources matrix in Cambodia, touching upon some socio-economic and ecological sustainability questions, as well as considering a few of the underlying geo-political issues facing Cambodia and its foreign suitors at this juncture in its history. The discussion is not intended to be comprehensive, but rather touch on some of the more salient observations that arose and perhaps spark some much-needed debate about this sector, given the general reluctance of some key institutions to internally assimilate and not repeat past shortcomings, at both the national and regional levels.


From Israeli to Indian aid:  The Prek Thnot river basin’s hydraulic development paradigm

This article highlights a brief and partial history of a river basin, located not far from the capital Phnom Penh, that has been the subject of numerous bi-lateral and multi-lateral hydraulic development schemes over the decades, stretching back to the post-colonial era of the early 1960s, when Cambodia was the subject of development aid overtures from a range of Western and East Asian actors and institutions, but lacked any real internal capacity to implement the schemes on offer.

Not that this dearth of local capacity was of much concern to the various foreign “experts” that have arrived in Cambodia at various junctures since with a development brief to hydraulically modify its rivers, as it was taken for granted that technology and knowledge transfer was part of the long term task, but in the meantime much of the actual development would be designed and implemented by overseas expertise and companies. It was also inherently assumed that the elites in government knew what the mass of ordinary people required and were the de facto best proxies in the development mission to rid the nation of the triple scourges of interlinked water scarcity (drought), floods and poverty arising from uncontrolled hydrology.

These main assumptions remain the dominant blueprint model of development to the present day, with small legions of foreign consultants sitting in offices worldwide, designing and planning projects that will determine the fate of Cambodia’s river basins and water resources well into the future. However, they are almost universally remiss at glancing backwards to the outcome of earlier interventions or looking laterally to neighboring country’s experiences, even when the exact same institutions have been involved in the same field over a period of several decades.

It is a peculiar “disease” of the international development industry, where there are few genuine incentives to learn valuable lessons from the past (and no real sanctions against repeating mistakes), accountability exists mostly on paper and it is rare to find an individual (let alone an institution) actually being held responsible for the consequences of the policies, strategies or projects implemented, even when they go demonstrably awry. In any case, many involved in the development industry privately acknowledge that much intervention they undertake is little more than a charade to keep the dollars flowing, so why question the value of the hydraulic engineering and managerial gravy train, much less stop it in its tracks?

I digress. Back to the river basin in question, namely the Prek Thnot (meaning “sugar palm”) river, that flows from the eastern Cardamom mountains through Kompong Speu and Kandal provinces, just to the south of Phnom Penh and discharges into the Tonle Bassac arm of the Mekong River. It is a highly seasonal river, with great variance in flow between the wet and dry seasons, making its control and management problematic in a complex and dynamic socio-ecological setting.

The foreign agencies (state and non-state) involved in Prek Thnot at one time or another, reads like a who’s who of development assistance to Cambodia: Australia, Israel, Japan, the Netherlands, Sweden, the United Kingdom were among prominent players over the years. Aside from state-linked institutions, there have been a number of non-government organizations involved in the past, adding a veneer of respectability to rather suspect blueprint “master plans”, including Australian Catholic Relief (ACR) which hired the Snowy Mountain Engineering Corporation Ltd (SMEC) to conduct a “reappraisal report” on the development of a “Prek Thnot Multipurpose Project” in 1991. This study looked at the feasibility of building a number of different project scenarios, to include a large hydropower dam with storage reservoir, flood control component and irrigation provision of up to 34,000 ha, under its most optimistic format.

The first major study and large dam proposal for the Prek Thnot basin was conducted by an Israeli government consultancy (Water Resources Development (International) Ltd) and submitted to the King Sihanouk regime in 1965, which envisaged a 70,000 ha irrigation scheme costing $34 million. The Prek Thnot Irrigation and Drainage Project was initially approved by the Committee for Coordination of Investigations of the Lower Mekong Basin in 1966, with construction of a large storage dam for hydropower and irrigation functions beginning in 1969, but the work had to be stopped a year later due to local fighting related to the escalating Indochina War.

A related diversion weir across the Prek Thnot river upstream of Kampong Speu town at Roleng Chrey was completed in 1973, designed to irrigate just 350 ha of land, but all foreign-funded work on the project halted entirely before the 1975 march into Phnom Penh of the Khmer Rouge, as the country descended into chaos. Some further work on canal extension using forced labor was carried out during the infamous “Pol Pot era” (1975-79), though it is unclear as to the efficacy of these works (the prevailing national narrative is that all irrigation works during this era were a resounding failure, though there is some dispute over the fairness of this general dismissal).

Since 1979, some minor domestic adjustments were made to the Roleng Chrey irrigation scheme but no major rehabilitation was carried out until a series of studies were commissioned in the late 1980s with a view to completion of the original large dam, some 12 kms upstream of the Roleng Chrey diversion weir. It was considered by Australia and other Western donors that a new dam at the old Israeli site would be essential to provide the capital with electricity and that significantly expanding irrigation provision in the downstream Prek Thnot basin would make Cambodia self-sufficient in rice and remove its dependency on foreign food aid. It was hoped that the Prek Thnot Multipurpose Project would be funded via a loan from the World Bank or Asian Development Bank, if the 1991 SMEC studies could be shown to present a financially viable option from three alternatives considered.

The silted up and poorly maintained canal drawing from the Roleng Chrey diversion dam today supplies a fraction of the area it was originally designed to, while some farmers with land next to it still draw water by hand.

Developing the Prek Thnot dam and storage reservoir in the 1990s was complicated by the fact that in the intervening years since the 1979 fall of the Khmer Rouge, many people had moved into the watershed area upstream creating a much greater resettlement component and thus increasing any associated compensation and mitigation costs. In the event and after conducting further studies, the large storage dam and reservoir for hydropower generation option was not financed by Western aid donors, but the downstream irrigation sub-schemes based on “run-of the river” diversions were constructed on an ad hoc basis, seemingly as a way of ingratiating the donor nation with Cambodia’s patrimonial government. Ignoring constraints on development imposed by the hydrology, this created an inevitable situation of severe over-allocation of available water resources and poor management outcome.

However, fast-track the situation to the last few years and over-extraction of water for irrigation is not the river’s only or most severe problem, as pollution from industrial development is effectively wiping out the aquatic health of the Prek Thnot river. In any case, with the rapidly changing macro-economic picture, rural people are now mostly disinterested in the meager returns and hard work that irrigated agriculture demands, even if there was a reliable water supply. Simply put, the local population are now turning away from agriculture to become factory employees and other non-farm work in droves and the Prek Thnot is being turned into an open sewer from unregulated human and industrial discharge.

A satellite image showing National Route 4 (to Sihanoukville) and Route 3 (to Kampot) running out of Phnom Penh city, with recently-built industrial factories located as ribbon development along each road. Many were seen to be releasing untreated waste water, which finds its way by small streams into the Prek Thnot river . NB: Krong Chbar Mon is the provincial capital of Kompong Speu, with the Roleng Chrey dam located about 6 kms upstream

The hydraulic development that has taken place on the Prek Thnot river system over the last four decades or so has been implemented in an ad hoc fashion, that has not fully taken into account the wider socio-ecological context of the river, nor addressed the underlying threats and constraints to its integrity, which are now becoming all too apparent as the river spirals into an increasingly degraded state. Instead, one agency after another has designed and implemented its own hydraulic fantasy project, based on an all-too-common, but fatal, mix of development hubris, flawed assumptions and self-interested guile of foreign consultants and their bureaucratic counterparts in the Cambodian government.

The most influential agency pushing hydraulic engineering solutions has been the Japanese government, principally via its Rehabilitation of the Kandal Stung Irrigation System Project, costing $19.26 million and completed in about 2007. This project aimed to rehabilitate an existing (“Pol Pot era”) irrigation system and supply a “beneficiary area” of 1,950 ha with irrigation. In practice, according to an ex-post facto evaluation of the project by a Japanese consultant in 2012 and based exclusively on Ministry of Water Resources and Meteorology (MoWRAM) data (so not independently verified), the project irrigated 1,593 ha for single cropped rice in the wet season, 339 ha of double cropped rice in the wet season and 294 ha of dry season rice.

Such bland data tends to exaggerate the impacts of a project, as they fail to incorporate an understanding of the degree to which rice can be cultivated in the “command area” due to non-project related hydrology in the rainy season. Some years when rains are plentiful, no additional irrigation is required at all.

However, there were evidently major issues with the project’s performance, reading between the lines of the report, and the report failed to convince this reader that significant extra water had been secured from the project’s low-head hydraulic structures to compensate at critical periods of the year, given the modest inflows to the system from upstream in the dry season. Overall the project was rated as “partially satisfactory” by the consultant, despite being constrained by a narrow terms of reference for project evaluation and thus, the questions that could be posed.

When I visited the project, due to upriver extraction and low natural flows there was extremely limited inflow to the project headworks, matched by a trickle of heavily polluted outfall below the weirs, reflected in a correspondingly small area of irrigated rice being cultivated, suggesting the Kandal Stung project is now largely obsolete and uneconomic for agriculture, just a decade after Japan’s investment. The entire project had the appearance of “abandonment”, with little operation and maintenance carried out and some of the hydraulic infrastructure was on the verge of collapse into the river bed (see picture below).

A building, possibly containing power turbines, built at the headworks of the Tuk Thla weir on the Prek Thnot river next to Route 3 showing downstream bank erosion and subsidence, which could lead to the collapse of the entire structure in the coming rainy season. Unknown aid donor, but quite possibly built under Japanese Kandal Stung Rehabilitation Project.


While the middle and lower Prek Thnot river basin has had one foreign-aided irrigation scheme after another superimposed on it over the course of the last three decades, none of which are economically feasible or ecologically rational, thus inevitably disappointing end users (while no doubt pleasing political elites – the true beneficiaries). The original target users – impoverished villagers –  have been voting with their feet for years, leaving the land en masse to work in non-farm employment, both domestically and abroad, meaning there is declining demand for irrigation services and agricultural livelihoods in any case, making the rationale for the aid projects largely obsolete.

Those that remain in the villages are increasingly dependent on off-farm remittances and while they might rhetorically profess to want to practice irrigated rice cultivation, in reality are severely restricted by lack of labor, lack of capital, insufficient water allocation (temporally and spatially) and generally poor economic returns available from the sector, vis à vis non-farm livelihood options. Thus, rural families with suitable land tend to stick to growing a single crop of rice in the wet season to provide a measure of food security, which is not entirely reliant on poorly managed and maintained public irrigation schemes, and spurn dry season cropping.

Yet despite this rather obvious socio-economic reality that has emerged in parts of Cambodia that are becoming more closely tied into nearby urban and wider regional and global markets, international aid donors still cling to old school irrigational approaches. For example, the government of India decided a few years ago to belatedly enter into the melange of existing hydraulic interests in the Prek Thnot basin, by constructing a large storage dam on the upper river in Aoral District, Kampong Speu, completed in 2015.

Described as being built by “state of the art technical expertise” from WAPCOS Limited (an Indian governmental enterprise under the aegis of the Indian Ministry of Water Resources, River Development and Ganga Rejuventation), the dam is a concrete-faced rockfill structure 21 m high and with a total storage capacity of 140 MCM, that supposedly benefits an irrigation command area of 10,000 ha. The project was reputedly implemented via a $30 million loan from the Indian to the Cambodian government, which supposedly will involve canal-building for irrigation provision in a Phase 2.

However, when I visited the site towards the end of the dry season, there was no evidence that this dam was benefitting a single hectare of land. Instead it was discharging foul-smelling water into the Prek Thnot river, a product no doubt related to the uncleared biomass left in its shallow reservoir, but also may be exacerbated by water releases from a sugar cane factory located near the reservoir inlet. The polluted water being released from the dam would almost certainly be harming aquatic life for many kilometers downstream. To all intents and purposes the Stung Talas dam (as it has been named) appeared to be a project without a purpose.

There were no government officials stationed at the dam and it gave an impression of abandonment, reinforced by locals living just a few kilometers away in Aoral district who were largely ignorant of its existence. It did not put food on their tables, water in their taps, irrigate their fields or homes nor benefit them in any way, so why should they care? It was clear that this was a dam built as a political device to improve economic relations between India and Cambodia, under a process showing a bare minimum of good governance credentials, but reflecting the new geo-political realities of the nation and wider region.

The Talas Dam located on the upper Prek Thnot river, Aoral District, Kampong Speu. It was completed in 2015, without clearing trees and other vegetation from reservoir bed, which is now slowly rotting. In March 2017, the water quality was very poor beneath the dam as a result.

The case of the Talas Dam, the Stung Kandal scheme, the Prek Thnot Multipurpose Project and other ill-fated plans and projects to hydraulically transform the Prek Thnot river basin for irrigational purposes over the past four decades are emblematic of a more general paradigm seen across the Lower Mekong Basin, yet scarcely acknowledged by the agencies and institutions that continue to seek to exercise their visions of “development” alongside those of authoritarian governments and despotic leaders.

The failure to study and learn the empirical lessons represented by the changing in-basin circumstances, past development interventions and resulting rapid degradation in the ecological health of the Prek Thnot river, especially given its proximity to Phnom Penh, should be a source of deep embarassment by the many “experts” involved in the national water resources development and management sector. It seems like a wonderful opportunity to study a near-at-hand case study and take seriously the much-abused notion of “sustainability” has been missed. Instead, there remains scarce interest in performing such detailed post-facto evaluative exercises of hydraulic development pathways, but an appetite for endlessly replicating past failures to serve narrow political agendas stays strong, ironically often among some of the very agencies that pressed for the utopian “multi-purpose development” schemes in the first place.

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