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Destruction of critical urban wetland risks the end of urban farming and wastewater treatment

Authors: Laura Beckwith and Melissa Marschke (University of Ottawa)

Sreymom [1] lives with her husband, two young sons and her elderly father at the edge Tompun Lake, situated on the outskirts of Phnom Penh, the capital of Cambodia. Sreymom is a morning glory farmer, cultivating this aquatic spinach on the lake’s surface. She moved to the area as a young girl, with her parents who were seeking opportunities to make a living near the city. At the time (1990s) morning glory farming seemed like a good option, allowing people to work in the early mornings and still have time at home, with the added bonus of being your own boss. Recently, however, morning glory farming has turned into turned into a higher-risk undertaking.

Heat and rain have become increasingly unpredictable, impacting how morning glory and other aquatic plants grow. For example, storms can be forceful and sudden, tangling up the ropes used to support the plants on the water’s surface and destroying entire crops. This impacts Sreymom’s ability to pay back loans (she borrowed $1000 several years ago, but cannot pay it back and now owes significant interest on her initial loan). To ensure their livelihood, Sreymom’s husband works in Phnom Penh’s booming but unreliable construction trade leaving her to oversee their farming activities and take care of the household.

Aquatic vegetables are brought to shore from Tompun Lake. Photo credit: Laura Beckwith

Not only is this wetland a critical livelihood source for Sreymom and hundreds of other local households, the Tompun wetland is the lynchpin of Phnom Penh’s wastewater management system. This wetland receives 70% of the wastewater run-off from the capital, Phnom Penh. There is no central sewage treatment facility for the city: water enters the wetland system containing multiple contaminants including nitrogen, phosphorous, E. coli, and detergents (Sovann et al, 2015). Aquatic plants serve as filters to clean wastewater; even so, contamination levels are increasing as the city grows and may soon outstrip the capacity of the morning glory fields. Deteriorating water quality is slowly choking the morning glory, and farmers such as Sreymom are suffering skin irritations and infections from exposure to pollutants. Households resort to using chemical fertilizers, an additional cost that most can ill afford, and likely further compounding water contamination.

Adding to these environmental challenges, Tompun Lake and its environs are slated for development. Over 75 percent of this wetland, which expands to over 2000 hectares in the rainy season, will be filled in (Phnom Penh Capital Hall and Ville de Paris, 2019). This follows a trend in Phnom Penh, which saw more than 6000 ha of natural lakes and wetlands lost to infilling as the built-up area increased six-fold between 1990 and 2015 (Mailhe et al. 2019). The infilling of Tompun Lake began in 2014 with the construction of Hun Sen Boulevard, built on reclaimed land and designed to open up the southern part of Phnom Penh to development. The construction of the road has blocked water circulation between the lake and nearby Bassac River, whose annual floods would normally inject much needed fresh water into the overburdened lake system. This has exacerbated issues of water contamination in addition to shrinking the space available for the morning glory farmers. Little by the little the lake is being filled in with sand to pave the way for the construction of a real-estate megaproject, ING City. At over 2,500 hectares, ING City is the largest of Phnom Penh’s seven planned satellite cities. Such projects are aimed at affluent clients and businesses: Phase I features a Mercedez-Benz dealership and the International School of Phnom Penh, an elite private institution. Subsequent phases are expected to bring a luxury shopping mall and numerous options for high end residential real estate, targeted at wealthy foreign buyers (ING Holdings, 2015).

Though Sreymom has found ways to cope with unpredictable weather and poor water quality, the loss of the wetland to in-filling will spell the end of her livelihood entirely. Sreymom’s story is not unique. Her village is home to over 350 families and the majority practice farming as their main livelihood. All of them are threatened by the way urban expansion is being driven, with little consideration of their claims to the lake. In Phnom Penh, many low income settlements have been evicted (often violently and with no compensation) to make room for real estate development (see for example Brickell, 2014). The infilling has therefore understandably provoked fear and anxiety amongst the farmers in Sreymom’s village, despite reassurances from local officials that their homes will be ringfenced as part of a planned reservoir. Though threats of eviction for Sreymom and others in her area have passed for the moment, the loss of their livelihood will bring their tenure into question regardless. All in all, the villagers are looking towards an uncertain future with the knowledge that their current situation cannot last, but no clarity as to what will follow.

The destruction of the Tompun ecosystem is a major loss that will be felt well beyond the farming communities living the lake’s shores. Phnom Penh will face major challenges with draining and treating wastewater once the wetland has been filled: there are no plans to build a sewage treatment plant that could handle the waste that the lake currently filters nor help control for floods. For example, the ‘pilot’ sewage treatment plant that is proposed can treat only 5,000 m3 per day, a fraction of the city’s estimated need which is closer to 280,000 m3 per day (Nishikawa, 2018). The wetland performs its treatment function at no cost to the city whereas a constructed system will require ongoing energy use, maintenance and running costs.

View of Phnom Penh from Tompun Lake. Photo credit: Laura Beckwith

Flooding will likely increase as the capacity of the lake system to retain and remove stormwater is diminished. Though in-filling has been underway for years, the city has yet to feel any serious impacts due to the vast size of the lake system and its enormous absorption capacity (Phnom Penh Capital Hall and Ville de Paris, 2019). As such in-filling continues, it is only a matter of time before it has both upstream and downstream impacts. The neighbourhoods immediately surrounding the lake (which include the Cheung Ek Genocidal Centre, one of Cambodia’s most visited tourist sites) will be at risk for flooding, as will the city center if flood water is restricted from exiting the (poorly maintained) wastewater canals or if it flows too rapidly into the Bassac River, thereby threatening the city’s dykes (Phnom Penh Capital Hall and Ville Paris, 2019). The potential health impacts of untreated wastewater are serious, likely impacting the poor and the rich living in the area.

Sreymom and other farmers in her community diligently employ what little resources they have to cope with the challenges they are experiencing. The changing weather worries them, but they suspect the encroaching development will probably reach them first and both threats feel far beyond their capacities when they are struggling to put food on the table. The lack of transparency in the strategic planning process at the city level makes it difficult to see how such projects will be halted (Beckwith and Keo, forthcoming). Local aspirations lie with the next generation. While many households retain ties to rural areas, for now their priority is to remain close to the city to access better quality schooling for their children. Parents hope that their morning glory farming can continue long enough for their children to complete school and find non-farming work in the city: ideally a job that is well paid, dignified and not as high risk as morning glory farming. This transition will need to take place soon, especially considering the deteriorating water quality, skin irritations and limited yields that current farmers face.

As more of the lake is lost each day, this strategy seems increasingly uncertain. The farmers will be the first to feel the loss of Tompun Lake but the absence of Phnom Penh’s largest wastewater reservoir is sure to be felt by all of the capital’s residents.


[1] For the purposes of this paper, the character of Sreymom has been created from a collection of elements from various field interviews in order to ensure the anonymity of participants while also being representative of the experiences of the community members.


Beckwith, L. and Keo, P. (Forthcoming). “The Discourse and Practice of Resilience Policy in Phnom Penh” in Sanderson, D. and Bruce, L. (Eds). Urbanisation at risk, Pacific and Asia. Routledge.

Brickell, K. (2014). “The Whole World Is Watching”: Intimate Geopolitics of Forced Eviction and Women’s Activism in Cambodia. Annals of the Association of American Geographers, 104(6), 1256–1272.

ING Holdings. (2015). Overall Project Concept. Accessed 1 April 2019.

Mialhe, F., Gunnell, Y., Navratil, O., Choi, D., Sovann, C., Lejot, J., Gaudou, B., Se, B., Landon, N. (2019). Spatial growth of Phnom Penh, Cambodia (1973–2015): Patterns, rates, and socio-ecological consequences. Land Use Policy, 87(June), 104061.

Nishikawa, M. (2018). ‘JICA’s Cooperation for Water Environment Improvement in Phnom Penh’. City for All. Royal University of Phnom Penh, Phnom Penh. November 29, 2018. Presentation.

Phnom Penh Capital Hall et Ville de Paris. (2019) Phnom Penh : extension et mutations.

Sovann, C., Irvine, K. N., Suthipong, S., Kok, S., & Chea, E. (2015). Dynamic Modelling to Assess Natural Wetlands Treatment of Wastewater in Dynamic Modeling to Assess Natural Wetlands Treatment of Wastewater in Phnom Penh , Cambodia : Towards an Eco-City Planning Tool. British Journal of Environment and Climate Change, 5(2), 104–115.

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