- Sri Lanka recorded more than 50 drowning deaths in the first five months this year.
- Faster currents on the outer banks of rivers can pull swimmers off balance, especially during the monsoon season when river discharge increases, researchers say.
- Experts observe multiple factors including flash rains, more silt and eroding riverbanks that impact the river flow.
- A 2020 study recorded how curvatures of critical meandering bends in Deduru Oya have increased between 1989 and 2021.
DEDURU OYA, Sri Lanka – On April 16, eight members of Priyantha Kumara’s family including his wife, son, brother, father-in-law, and four other relatives were swept away by strong currents in the Deduru Oya, a river in Sri Lanka’s North Western province. Sri Lanka Police reported more than 30 drowning deaths between April 12 and 21 this year, underscoring the risks posed by flooding rivers.
Sri Lanka Police media spokesperson Udaya Kumara Wootler told Mongabay that 376 individuals have died due to drowning in rivers last year while 595 fatalities were reported in 2024. Buddhika Sampath, spokesperson for the Sri Lanka Navy told Mongabay that the Navy Diving Unit recovered 148 bodies of people between May 2022 and May 2023. While the police are yet to disclose official statistics of deaths due to drowning from January to May 2026, the number of reported incidents show over 50 fatalities.
Kumara is a resident of Gopallawa in the northwestern district of Kurunegala. His son had requested that they all go for a bath in the river. The group had been bathing at a popular spot named Kuriyagas Mankada when they met the tragedy.
“My son was only 13 years old, and he was a bright student,” Kumara told Mongabay. “My brother was about to hold a housewarming ceremony at his newly built house. But all these dreams were shattered within seconds. My father used to take us to this same spot to bathe when we were young. But the river has changed now, especially after Cyclone Ditwah. None of my family members knew how to swim. People should not bathe in rivers if they cannot swim,” he said.
Dynamic river system
Deduru Oya is the fifth largest river basin in Sri Lanka, covering over 2,600 square kilometers (1,615 miles). Its reservoir, which has a maximum spill capacity of 34 million cubic meters, was forced to make emergency water discharges in November 2025 during cyclone Ditwah. The cyclone triggered severe flooding, landslides and widespread displacement while affecting over 2.3 million people across all 25 districts of the country.
“A river is a dynamic system and river profiles change all the time,” Lasantha Sooriyabandara, engineer and director of Hydrology and Disaster Management at the Irrigation Department told Mongabay. “Water has a lot of energy and if water levels exceed the capacity, the soil layers on riverbanks detach. Different rivers have different depth profiles and the layout shifts frequently. Due to heavy currents, meanders readjust themselves and riverbanks erode. As such an entire river gets redefined, changing its path, range and rhythm,” he said.
A 2022 study using satellite remote sensing data in the lower Deduru Oya found that the Deduru Oya has undergone considerable change over time with the river altering its curvature and the rates of change in its course. According to the research, the curvatures of the critical meandering bends have increased over a span of 32 years from 1989 to 2021. Similarly, the annual meandering rates were observed to be higher in recent years compared to the past.
Speaking on how extreme weather events impact rivers, Vindhya Basnayake, lead researcher of the study who focuses on river hydraulics and flood risk management, said that extreme weather events (such as extreme rainfall events) could increase the energy of rivers due to increased river discharges, and velocities. “This means during extreme events, meandering rivers will experience more erosion at the outer banks and sedimentation at the inner banks, resulting in an accelerated river migration, and in some cases creating new channels,” she told Mongabay.
Increasing deaths due to drowning
She noted that in meandering rivers, outer banks are eroding frequently, causing a weakening of the banks. “This could be a cause for increased number of drowning cases, especially due to lack of awareness on the possibility of erosion. In a meander, water moves faster along the outside of a bend, eroding the bank and creating deep channels. People who enter the water at what appears to be a shallow spot can suddenly fall into deep water,” she said.
According to Basnayake, the currents, or the speed of water, around bends remain uneven. As a result, faster currents on the outer bank can pull swimmers off balance, especially during the monsoon season when river discharge increases.
According to Sooriyabandara, river velocity increases after a flood and places that were previously suitable for bathing may not exist once the floods subside. “Floods also increase the amount of silt deposited at the riverbed. When slopes get eroded, it impacts the speed of river flow. In certain places, it impacts the stability of the soil as well. A river should have the space to expand and flow freely,” he said.
Nilusha Darshana from Kohilawatta has over 25 years of experience in rescuing people from drowning and sometimes retrieving bodies of people who have drowned in the Kelani River, a river flowing through the Western province. According to Darshana, the water levels in Kelani River increase by about 4-5 feet (0.9 – 1.5 meters) during afternoon hours. “During the dry season, when river water levels drop, ocean tides and salt water from the sea push up the riverbed,” Darshana told Mongabay. “During the rainy season when spill gates of reservoirs in upper areas of the country are opened, much of that water flows into the Kelani River, which eventually flows to the sea. Sand mining and other activities have resulted in deep pits being formed in the river, posing a serious threat to people. Therefore, it is best to ask a local about the conditions of a river prior to getting into it and risking your life,” he added.
Changing monsoon patterns
Meanwhile, a shift in monsoonal patterns has caused large volumes of water to be flushed into rivers. Sevvandi Jayakody, senior professor at the Department of Aquaculture and Fisheries at the Wayamba University observes that in recent years, the amount of sediment that is being flushed into rivers have increased dramatically. “Fine particulate matter gets sedimented and even though you think that the water is shallow, it has turned muddy at the bottom,” Jayakody said.
Apart from rivers, it has become equally dangerous to bathe in reservoirs. Jayakody noted that due to the clearing of catchments in reservoirs, it has become risky for people to bathe in reservoirs as well. “Due to deforestation, rain falls directly to the ground. Most reservoirs in Sri Lanka are part of cascade systems where the water naturally flows from one elevation to lower elevations. The ‘sink,’ or the reservoir at the lowest elevation, of all these reservoirs eventually accumulate a lot of mud. During the dry season, people get into reservoirs to mine clay. As a result, more pits are being dug out during the dry season,” Jayakody added.
Meanwhile, the sudden spike in drowning deaths over recent months has turned into a social issue. In response, plans are underway to initiate a national level mechanism to prevent deaths from drowning.
Sooriyabandara said that the department has facilitated the construction of safe bathing spots by collaborating with municipal councils in respective areas. “Drowning deaths are preventable, but people need to be mindful as well,” he said.
“The take home message is that water is a deceptive element,” Jayakody noted. “A river is a dynamic system and with flash rains like what we are currently experiencing, the river flow gets rearranged,” she added.
Banner Image: Bodies recovered from the Deduru Oya following an April 16 drowning incident this year. Image courtesy of Nimal Premachandra.
Citation:
Basnayaka, V.; Samarasinghe, J.T.; Gunathilake, M.B.; Muttil, N.; Hettiarachchi, D.C.; Abeynayaka, A.; Rathnayake, U. Analysis of Meandering River Morphodynamics Using Satellite Remote Sensing Data—An Application in the Lower Deduru Oya (River), Sri Lanka. Land 2022, 11, 1091. https://doi.org/10.3390/land11071091
Cite this article
Kamanthi Wickramasinghe (2026). Sri Lanka’s recent drowning deaths linked to aftermath of extreme weather events. Mongabay Conservation news. DOI: https://doi.org/10.66709/news-320930Credits
