The pools surrounding the Angkor Wat not only provide excellent opportunities for sunrise reflection photos, but also are essential for keeping the world wonder standing.
The Angkor Archaeological Park’s system of ancient reservoirs and channels stabilise the temples built atop sandy soil and groundwater underneath provide additional support.
For the hundreds of families living within and around the forests of the Angkor temple complex, use of this water is restricted by the Authority for the Protection of the Site and Management of the Region of Angkor (APSARA).
“The temple could collapse if you do not have enough groundwater,” said Phoeurn Sokhim of the APSARA water management department. “Most of the big temples depend on the groundwater as the foundation.”
Yet there is not enough groundwater to meet competing needs in and around the city, nor is there currently sufficient surface water storage from rivers, lakes and reservoirs to provide an alternative, local authorities and researchers say. Most communities and businesses around Siem Reap depend on groundwater.
Em Yean lives within the zone controlled by APSARA and said he uses the rain to water his fields instead.
“Even though there are water canals in Angkor, we cannot pump them into our rice fields because the APSARA authorities do not allow us to use it,” the seventy-seven-year-old said.
The regulations are a reminder of Siem Reap’s water scarcity issues. APSARA is one of several local authorities attempting to manage a limited water supply which must balance maintaining the UNESCO world heritage temples, irrigating fields for surrounding farming communities and supporting a city where several million tourists visit in non-pandemic years.
The Cambodian government has outlined goals to connect 100% of urban households to clean drinking water by 2025. At the same time, Siem Reap aims to significantly increase tourism in the coming years, which could further sap groundwater supplies.
“Groundwater resources are ‘out of sight, out of mind’ because there is a feeling of infinite use,” said Dr Sangam Shrestha of the Asian Institute of Technology (AIT) in Thailand. “Many cities rely on groundwater because surface water is not available.”
Shrestha is part of an AIT-led team of researchers aiming to survey the different uses of groundwater across Siem Reap to develop regulations and policies to sustainably and equitably manage an increasingly scarce water supply.
Without effective regulation and distribution policies, water access becomes unequal, said Dr. Khy Eam Eang, a hydrology researcher at the Institute of Technology of Cambodia and part of the AIT team. Hotels and wealthy families can afford to access groundwater and infrastructure but poor communities cannot. Greater coordination and planning across agencies is needed, he added.
“When we use many different sources and not any regulation, we cannot manage the condition of water well,” Khy said. “We need to be able to balance groundwater and surface water usage.”
Siem Reap has three main water sources: groundwater, the Tonle Sap Lake and the Angkor-era reservoir West Baray, which collects water from several rivers and stretches across a plain of rice fields and forests filled with 56 million cubic metres (1.98 billion feet) of water.
Under the control of APSARA, West Baray allocates 17,000 cubic metres (4.49 million gallons) of water per day to Siem Reap city, comprising the majority of the 30,000 cubic metres (1 million cubic feet) per day of water the Siem Reap Water Supply Authority (SRWSA) provides city residents, according to Seak Pengkeang, SRWSA deputy director general.
This is not enough to match Siem Reap city’s average demand of 60,000 cubic metres per day (2.1 million cubic feet), which SRWSA expects will increase to 80,000 cubic metres (2.8 million cubic feet) by 2030.
Businesses are forced to find alternatives and back up sources, Rambutan hotel general manager Tommy Bekaert said. Many rely on filtered water tanks, which are expensive but can help weather stretches of limited water availability.
Technically, APSARA prohibits the use of groundwater for businesses within the far-reaching protected zone of the Angkor park, but almost all companies still use groundwater, said Phoeurn, APSARA’s deputy director of water management.
While the city’s water system is improving, Rambutan’s Bekaert said in the past the shortages caused serious challenges for businesses.
“If you were relying on city water, you would have no water half of the day,” Rambutan’s Bekaert said. “You’re not allowed to use well water, but what do you do then?”
Most companies have wells as backup and the restrictions are not fully enforced, he explained.
Groundwater is fine for families, however when used by hotels and big businesses it will create too much stress on underground pools of water known as aquifers, hydrology researcher Eang said.
To take pressure off groundwater use, authorities are searching for ways to increase surface water storage and access.
APSARA plans to rehabilitate the ancient East Baray reservoir, but officials noted this would require the logistical challenge of resettling thousands of people.
“In the future, the city will grow and the needs of the water will increase,” Phoeurn said. “So that’s why we try to restore the ancient reservoirs to be sure that in the future, even as the city grows, we have enough water to provide.”
To meet this demand in the short term, the Japanese International Cooperation Agency (JICA)is helping Siem Reap construct a water purification plant capable of withdrawing 60,000 cubic metres (2.1 million cubic feet) of water per day from the Tonle Sap Lake or 21.9 million cubic metres (773,000,000 cubic feet) annually.
The plant is scheduled to be finished by the end of this year and would triple the city’s water supply and meet the capacity until 2030, SRWSA deputy director general Peangkeang said.
“Pumping to supply water to the city will not cause any negative environmental consequences and exacerbate water shortage in the surrounding area because the pumping amount is extremely small compar[ed] to the hug[e] water amount of the [lake],” he wrote in an email to the Globe.
The Tonle Sap Lake and surrounding farming and fishing communities are under significant stress, as climate change, drought and environmentally destructive upstream dams across the Mekong region have led to historic low water levels in the Mekong and the lake. Largely due to upstream damming, the Tonle Sap Lake is withering away, with conservationists predicting it could virtually disappear in the next two decades if no interventions are made.
JICA project formulation advisor Aya Tokumoto said the agency and various government authorities conducted feasibility studies to assess the purification plant’s effect on the Tonle Sap Lake and surrounding communities in 2011, concluding there would not be a “significant adverse impact on the environment.”.
JICA will assess the purification plant’s impact three years after beginning operation, she said.
Incorporating surface water to supply the city will be more sustainable for Siem Reap than relying primarily on groundwater, in part because it is easier to monitor surface water quantity and quality, Tokumoto said.
Meeting the national government’s goal of connecting all of Siem Reap province’s 1 million people to water by 2025 is unrealistic. It is impossible for many Siem Reap residents to gain access to clean water or connections to the public water supply, according to Massimo Maio, operations director of Water for Cambodia, which tests water quality and builds wells.
Farmers also struggle under ongoing drought to access water. Many people live too far from APSARA’s canals to receive water from West Baray in the dry season, APSARA officer Roan Vichet said.
“We don’t have enough water for all agriculture in the zone. So only some people along the canals do agriculture,” he explained.
APSARA supplies more than 100 square kilometres (39 square miles) of farmland with water, but in the dry season can only reach around 70 square kilometres (27 square miles), APSARA representatives said.
Some officials blame the water shortage on what they claim is farmers’ overuse of water during the dry season, calling for harvest restrictions to one per year.
Besides the decreasing monsoon season floods which farmers around the Tonle Sap relied on for natural irrigation, the region lacks efficient irrigation infrastructure. Only 30% of irrigation needs are met annually and only 15% during the dry season, according to the Asian Development Bank.
Communities outside the APSARA zone rely on rain and a patchwork of different reservoirs and irrigation networks often constructed by the farmers’ themselves to sustain their rice paddies and farms. In the dry season, communities must compete with each other in unregulated efforts to capture and channel irrigation water.
In the monsoon season in early august, the villagers of Bpring gathered for their annual ceremony to seek rain for their parched fields in Chi Kraeng district, 65 kilometres (40 miles) from Siem Reap city centre.
Everyone in the village relies on rain water to cultivate their rice fields, said Hong Chan, yogi archbishop at the Chi Kraeng pagoda.
To the percussive beat of traditional instruments, village elders swayed hands and hips in hope of stirring the weather. They called for the forest, temples and the famous Kulen mountain to come together with their ancestors to bring more rain.
On top of the spiritual appeals, Chi Kraeng farmer Thon Thin said he is switching to banana planting, which requires less water than rice.
A local NGO determined the region was not suitable for drilling, he said. Instead, villagers often dig ponds on their property to store water and pump to their fields during the dry season. Thin has a pump, but most of his community cannot afford to use pumps for farming.
“We need equipment to pump water out, which means we need to spend a lot of money,” he said. “And because we need to spend money, that’s why we cannot have a balanced price between selling and spending.”
His neighbour, 65-year-old Ont Ron, said paying 10,000 riel ($2.50) per-hour to pump water to irrigate her family’s rice field in the dry season is too expensive, so they do not grow anything. For everyday use, they pump water from a nearby river.
“In order to have enough water [to farm], we need a canal and a machine,” she said.
Outside the reach of the urban-focused infrastructure improvements, short of building additional costly canals and water storage systems themselves, for the Bpring villagers there is always the rain ceremony.
“There is no water in the soil,” Ron said. “If we don’t have water we don’t know what to do.”
This article was supported by a grant from The Stockholm Environment Institute.