Canals in Cambodia

On my way back to the US there was a front page story in the International Herald Tribune on Pol Pot era canals being revived in Cambodia.  Since then I’ve been thinking about canals and irrigation (I know, I know – who hasn’t?).  If you’ve been thinking about canals too, you can read more after the jump.


Above: An ancient (maybe?) canal near Banteay Chhmar temple in Banteay Meanchey province.

Angkorian and Pre-Angkorian Canals

In April 1975 when the Khmer Rouge took power all of Phnom Penh was evacuated and hundreds of thousands of people were moved to the countryside to begin creating a perfect socialist agricultural economy, dependent on growing rice with the aim of producing two or three tons of rice a hectare.

As the IHT article succinctly writes:

The leaders of the Khmer Rouge were obsessed with canals, embankments and dams. They presided over hundreds of irrigation projects to revive Cambodia’s glorious but perhaps mythical past of an agrarian wonderland.

This myth of Angkor as an “agrarian wonderland” was perhaps spurred in part the writings of the the Chinese ambassador Zhou Daguan who visited Angkor in the late 13th century and wrote that Cambodians could produce three or four crops a year.  Even earlier Chinese visitors to Funan, around the 3rd century AD, describe the Cambodians as follows:

The devote themselves to agriculture.  The sow one year and harvest for three.

[More info on Chinese accounts of Cambodia can be found in this book].

I’ve talked about the canals around Angkor Borei before. The LOMAP team has worked to date one of the canals at Angkor Borei and found that the canal appears to have been constructed sometime between the first millennium BC to the mid-first millennium AD.  You can read more about the dating of the canal in this article: Bishop, P., D. C. W. Sanderson, and M. T. Stark. 2004. OSL and Radiocarbon Dating of a Pre-Angkorian Canal in the Mekong Delta, Southern Cambodia. Journal of Archaeological Science 31:319-336. Which can be found here.

When the French arrived and started mapping Angkor and the surrounding environment they noticed vast hydraulic systems.  Bernard-Philippe Groslier was the first to think about these hydraulic networks and hypothesized that they were used for agriculture and irrigation.    For a long time this hypothesis was challenged, primarily because some of the major water features at Angkor- the East and West Barays- had no obvious inlets or outlets that could be used for agricultural irrigation.  This led to a hypothesis that these water features were religions in nature and not functional. [For one take on this see Van Liere, W. J. 1980. Traditional Water Management in the Lower Mekong Basin. World Archaeology 11 (3): 265-280. Available via JSTOR].

That is until further work was done by Christophe Pottier and the EFEO; their extensive maps and research showed that the barays had inlets and outlets that were part of a larger agricultural irrigation system.    This research has been continued more by Damian Evans and the Greater Angkor Project who recently published an article about their work and the extent of the settlement at Angkor- you can read it here.   The image below is a portion of the map they produced and shows the extensive, complex water system-including canals- that existed during the Angkorian period.


From: Evans, Pottier, Fletcher, Hensley, Tapley, Milne, and Barbetti. 2007. A comprehensive archaeological map of the world’s largest preindustrial settlement complex at Angkor, Cambodia. Proceedings of the National Academy of Sciences of the United States of America 104 (36): 14277-14282.

From the same article:

Pottier also showed decisively that the great reservoirs, or barays, had inlets and outlets and were connected to a network of channels  and embankments, contrary to the assertions of critics of Groslier’s hydraulic thesis from the 1980s onwards (11–14). Moreover, the longstanding assumption (2, 11) that the extensive agricultural field systems visible on the surface today might date from Angkorian times was supported by his new map, which displayed the integral connection between the local temples and their agricultural space (15). Various other elements of the classical Angkorian landscape, in particular, the small ponds described in an account of Angkor in the 13th century (16), have also persisted on the surface, were clearly identifiable from the air and have often been renovated and reused by the contemporary Khmer population.

This is really really cool.  The Angkorian people dramatically and drastically changed the physical landscape of Cambodia in a way that you can still see on the surface today.  Using satellite images and radar is something that Damian Evans is still working on- I discussed it much earlier this year when I was doing survey with him and another colleague in NW Cambodia.  Using aerial photos are really helpful for this kind of archaeological work because many of these features are  hard to spot on the ground, unless you know what you are looking for.

So from this most recent archaeological research we know that the settlement area around Angkor was HUGE and that the Angkorian empire relied in part on a complex hydrological system.   Groslier hypothesized that a failure of this system led to the downfall of Angkor- something that also seems to be supported by the archaeological evidence.  Again I quote from the Evans et. al. PNAS article:

The new maps show that landscape modification at Angkor was both extensive and substantial enough to have produced a number of very serious ecological problems, including deforestation, overpopulation, topsoil degradation, and erosion. Whatever the functions of the infrastructural network, the impact of extensive clearance for rice fields, the economic and demographic consequences of constant modifications to the land- scape, and unpredictable events such as flooding or war fare would potentially have been extremely serious for such an elaborate and interlinked system. The Siem Reap river is now incised 5– 8 m into the Angkorian floodplain, and a major canal in the south of Angkor that postdates the 14th century CE is entirely filled with cross- bedded sands, indicating rapid movement of large quantities of sediment-laden water (8). There is also evidence, particularly in the newly mapped northern region, of ad hoc adaptations, breaches, modifications, and failures within this system, suggesting that it became increasingly complex and unmanageable over several centuries of development (Figs. 4 and 5).

This is something that the GAP team is continuing to investigate, but it is important to note that canals and irrigation systems take a lot of labor to produce and require constant maintenance.  Which is why so many of the Khmer Rouge era canals went out of commission.   Now they are being repaired by some of the same people who helped construct them originally.  From the IHT article I mention above:

The irrigation system in Baray, which is fed from water diverted from the nearby Chinit River, functioned for several years after the Khmer Rouge left power. But in the mid-1980s it fell into disrepair. It was only in 2005 that the government began rebuilding it. Today, the local municipality hires a maintenance crew to keep the water flowing.

Among the workers is Sim Vy, 48. As a teenager she was enlisted by the Khmer Rouge to help build the canals. She was told she was working for national glory but received only a watery gruel as recompense. Now she is paid $55 a month. “I prefer working this way,” she said.

Khmer Rouge Canals


“This file photo taken 16 April 1976, shows people digging a water canal under the guard of an armed Khmer Rouge soldier taken in the Battambang Province, by a Cambodian who later fled and found refuge in France.” Via.

During the French colonial period there was also construction of canals (and filling in of areas in and around Phnom Penh).  However the scale was nowhere near as extensive as during the Angkorian period.  The next major change to the physical landscape in Cambodia was not until the Khmer Rouge period. The scholar Jeffrey Himel has been studying Khmer Rouge irrigation and wrote an interesting and detailed study that you can read here.   In this article he describes how the Khmer Rouge arranged a nationwide network of  irrigation canals arranged in a  grid or along UTM lines.  This was part of an overall strategy to collectivise the agriculture and by extension society.


Above: Workers building canals during the Khmer Rouge period from the book “The Murderous Revolution” by Martin Stuart-Fox. Via.

As Himel notes, this strategy was not particularly effective:

Examination of the irrigation works in the post-Khmer Rouge period has allowed clear definition of the many problems caused by the new system. The hydrology of the overall system was deeply flawed. Canals of tens of kilometers in length were dug connecting adjacent watersheds together. But this complex interweaving of canals and catchments was controlled by local cadre according to their immediate needs. Thus, there was no way to predict or adjust the effect of one canal or weir closing on the rest of the system nor any communication between those operating different parts of the system. The natural drainage patterns were badly disrupted and the new routes caused unexpected flows to occur that could not be predicted by the local people who had lived there for their entire lives.

Needless to say, these massive rice harvests were not achieved and thousands of people died of starvation.  However, as I mentioned above it now appears that some of these canals are being revived in the hopes of once again improving Cambodia’s rice harvest.   What is important to remember is that there is not an easy fix to this problem.    Himel concludes his paper nicely by stating:

The main lessons that can be summarized from the sad experience of Democratic Kampuchea serve as a confirmation of much that has evolved as modern irrigation practice, including:

1.  The importance of proper technical design and implementation.
2.  The need to identify innovative, competent and popular local leadership free of outside politics.
3.  The necessity for local adaptation, bottom-up planning and flexible approaches to irrigation and agriculture.
4.  Maintaining a step-by-step and learning approach appropriate to the capacity of the people
and agricultural system.

In addition to reviving some of the Khmer Rouge canals it seems that people are also starting to revive some Angkorian period water features as well!  The Phnom Penh Post reports on an Angkorian reservoir near Siem Reap that has been repaired and will provide irrigation for 9,ooo people in the area.

People in Cambodia have faced a constant struggle to manage their landscape since the Angkorian period and before.  There is not a “set it and forget it” solution to irrigation and agricultural production in Cambodia.  What is interesting is how people are learning from the past and adapting to it to fit their present conditions.

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7 responses to “Canals in Cambodia

  1. “Needless to say, these massive rice harvests were not achieved and thousands of people died of starvation.”

    I’m probably totally wrong about this, not my area, but I thought I read somewhere that rice production went up during the DK period and that starvation was caused primarily by the KR trading their rice for weapons with the Chinese etc? Of course, that wouldn’t necessarily contradict the fact that their main projects didn’t work – with so many extra labourers in the countryside they didn’t have to for production to increase.

    Interesting post either way, I never thought I’d voluntarily read that much about canals and still be curious to hear more at the end. I think I need to get out more :(

  2. So, this is a very good post.

    I have some wording issues though:

    I do not agree that there is a constant “struggle” to manage the landscape, any more than people struggle to manage any natural resources (people struggle to farm or sell stationery or whatever, too). That language sets up a Man and Nature dichotomy, which is not very useful for thinking about social-ecological systems (we’re talking about/living in all one system, right?).

    I also do not think that they are necessarily *learning* from the past and adapting it to present day needs. The landscape is there, and it is used. Just another resource. I doubt that there is much of an intellectual link between
    ancient people and the people of today.

    I absolutely agree that it is really neat that people continue to use the same landscape features which were designed and built in days of yore. And in some cases, re-purposing them.

    I guess I just have some semantic differences with your closing paragraph more than anything else. Landscape history one of the ice floes upon which I have an intellectual foot planted, so I am reading a little closely…

  3. Rob- thanks for the comment! I’m actually not sure about the amounts of rice produced during the KR although that is an important point you bring up. I think my wording made it seem like there was a one to one correlation between a failed irrigation system and the starvation of the Cambodian people when in fact things were more complex. I’ll quote from Himel again on that:

    “Finally, the overly ambitious targets for rice production resulted in local cadre collecting the rice produced and shipping it back to the central authority without keeping sufficient food for the
    people. The meager rations, harsh working conditions, heavy work load, lack of medicine, and often unsympathetic cadres led to many deaths from exhaustion, disease, starvation and execution. The workforce was progressively weakened and reduced as their workload increased. Internal purges of the local and regional leadership resulted in changes in leaders and large movements of people, thereby further destabilizing agricultural production. “

  4. Thanks Mandevu for your comments and I agree- I should be more careful about my wording. As for learning from the past– that would make for an interesting cultural anthropological project (i.e. how much is the landscape just used vs. an actual connection with the past). In Cambodia where Angkor is constantly used for nationalist rhetoric I wouldn’t be surprised to see people connecting their everyday work to the glorious Angkorian Civilization as a means to build civic pride. Who knows if it is happening yet. Archaeologists like to talk about this stuff tho (using the past to help the present) because it makes our work seem more relevant!

  5. We all want our work to be relevant! I know that I can be a little wild with my assertions if professional importance too.

    The past to present issue is an interesting one, particularly when you layer in the politics (as you have nicely in previous posts).

    As a foreigner working in a landscape which has a lot of evidence of human activities (no canals, just mounds and ponds), I am always fascinated by the juxtaposition of past and present. However, when I mention it to the farmers I know (“You know, those ponds are probably more than a thousand years old!”), they are not too interested. Or, they respond as if I was stating the obvious (which I likely am).

    But this is not Angkor I am talking about. The government does not valorize flooding savanna as some sort of cultural heritage. Quite the contrary, in most cases it is a considered wasteland to be “developed.”

  6. This post is absolutely fascinating, I followed the link to your name from SEAArch. :) I’m working with Khmer shipbuilding traditions and I’m very interested in canals as a means of transportations (or not). But I have to give it a little thought so I’ll just add you to my blog roll to keep track of your posts and read this entry carefully. :)

  7. Thanks Nemi- your research sounds interesting too and I’m looking forward to checking out your site!

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