Tonle Sap, Cambodia – During Cambodia’s monsoon season, rice farmer Sam Vongsay’s backyard fills with water and plastic litter for his house neighbors while Tonle Sap Lake grows with flood waters from the Mekong River.
But during the dry half of the year, which runs from December to May, Vongsai couldn’t reach a drop of lake water from his home in Chung Kniss, which is about 220 kilometers (137 miles) northwest of the capital, Phnom Penh.
The 40-year-old farmer lacks a viable well or the equipment to pump lake water two kilometers (1.2 miles) from his property, and blames farmers upstream for diverting much of the flow to irrigate their crops.
“The water is not enough to reach the riverbed, because other farmers upstream also block the water,” Fongsai told Al Jazeera.
In the past, Fongsai and his family could grow two seasons of rice, but the lack of rainfall in recent years and inadequate water infrastructure made it difficult to manage a single crop. Fongsai said he tried planting hot peppers last year to diversify his crop, but the plants withered and died.
“We don’t have enough water infrastructure,” he said. “If we had that, we would not only grow rice, but rice and other vegetables three or four times a year.”
Farmers along Southeast Asia’s largest freshwater lake face a growing threat to their livelihoods as growing land demands, drought attributed to climate change and hydropower development, deplete precious water supplies.
Since 2018, the volume of the Tonle Sap has fallen below its historical average, according to a Mekong River Commission (MRC) report that examined water levels between November 2020 and May last year.
The lake was hit by a severe drought in 2019, as has the Mekong River system on which it depends, leaving a lasting impact on water levels. In January 2020, the lake had a volume of about 6,000 million cubic metres, just over a third of the average dry season volume, according to the Migrant Resource Center.
Phan Ra, a rice grower in Siem Reap, 44, told Al Jazeera that the weather had not improved since the 2019 drought, with last year’s non-monsoon winds and rain exposing the seeds laid in the ground during the dry season.
To cover the costs of renting his farmland and spraying fertilizer – which he needs to do frequently due to erratic weather – Ra tried to plant rice twice last year.
“It was useless because I had almost nothing to harvest,” he said. “Doing this twice is impossible because there is not enough water.”
Population growth and rising land prices have led to a rush to deforest the area for homes and farmland, increasing demand for water from the lake and its tributaries.
The lake, whose seasonal flooding is linked to thaw from China’s Tibet Autonomous Region and Yunnan Province, is also vulnerable to expanding hydroelectric dam development, which scientists have linked to unexpected water levels on the Mekong River.
While farmers have felt an increasing pressure on their livelihoods, the Tonle Sap fishing industry, which produces an estimated 500,000 tons of fish annually, has also reported smaller catches, prompting some fishermen to turn to fish farms or farming.
Brian Eller, author of The Last Days of the Great Mekong, told Al Jazeera that in addition to hydroelectric dams on the Mekong, smaller reservoirs built to meet farmers’ needs – often without official approval – were pressing the lake.
“These reservoirs effectively steal water from surrounding communities and impede critical fish migration paths in the world’s largest inland fisheries,” Eller said.
Vongsay, a farmer near Tonle Sap, said the expansion of a canal along his property in 2019 that was supposed to help him and other farmers access more water from upstream caused him to stop farming altogether.
Fongsai said, explaining that he was unable to drive his rented tractor across the expanded canal to plow his rice field.
Fongsai said he and his family had been living off a side business making decorations for Buddhist holidays.
The combined effects of climate change, deforestation and infrastructure development in the Tonle Sap showed that authorities needed to gain a better understanding of the delicate nature of the Mekong region, Shea Silla, a researcher with the USAID Mekong Wonders Project, told the island. Water supply and development solutions that take these factors into account.
They are interconnected. When people use more water without saving or restoring, there will not be enough ground and surface water.” “Even [if] We have enough infrastructure for irrigation, and we don’t have water from [groundwater] Spring as well as from precipitation. It’s still hard to get enough water for a year and [will be] In the future.”