Early downpours expose Kathmandu's fragile drainage, raising concerns over what the full monsoon might bring.
KATHMANDU, MAY 6
Just a few days of pre-monsoon rain have thrown parts of Kathmandu Valley into disarray, with severe waterlogging and flooding offering residents an early preview of the monsoon season - still weeks away.
Rainfall over the past few days has left several areas inundated, with roads waterlogged and traffic thrown into disarray. On Tuesday morning, the Bishnumati corridor was flooded, severely affecting vehicular movement. The northern gate area of Narayanhiti Durbar was also inundated. In Kathmandu Metropolitan City-19, water pooled in the Kankeshwori area due to inadequate drainage, hampering traffic flow.
Lalitpur's Kalopul area faced similar problems, as the Bagmati corridor overflowed. A bit more rain could push other riverbank areas - including Balkhu, Bafal, the Dhobikhola corridor, and Sundarighat - into waterlogged conditions as well.
Corridors built to ease traffic congestion have become flood-prone zones, even after moderate rainfall - a result of haphazard urbanization, encroached riverbanks, and inadequate drainage infrastructure.
"There are various reasons for the inundation in Kathmandu Valley," said Pradip Khatiwada, Executive Director of Youth Innovation Lab, an organisation working on disaster information management. "Rapid and mismanaged urbanization, river encroachment, and excessive concrete surfaces have left little room for rainwater to seep into the ground."
According to Khatiwada, the inundation across Kathmandu is not solely due to rainfall volume. "Most of the land in the city is covered with concrete - buildings, pavements, and roads - leaving no space for water absorption. Rainwater, unable to seep into the ground, flows directly to low-lying areas that lack proper drainage and floods them," he explained.
Moreover, the destruction of hills around the Valley has contributed to soil erosion. "Sediments are washed down during rainfall and settle in flat areas, clogging already outdated drainage systems and further aggravating the problem," Khatiwada said.
The issue is not just local. Across Nepal, the pre-monsoon has triggered landslides, flooding, and road disruptions - particularly in remote regions and on major highways. The Daunne section of the Narayanghat-Butwal road along the Mahendra Highway was disrupted on Tuesday due to heavy rainfall, slippery surfaces, and muddy conditions.
This year's pre-monsoon impact is especially severe because much of the country's infrastructure was already weakened by last year's record-breaking rainfall. In the 2024 monsoon, rainfall exceeded the seasonal average by 25 percent. On September 27 and 28 alone, rainfall spiked 32 percent above normal, leading to widespread damage that has yet to be fully repaired.
"Flooding in the Kathmandu Valley isn't just about poor drainage," Khatiwada emphasized. "Sometimes the rainfall is so heavy that not only surface water but also underground water resurfaces, causing flooding even in areas not directly connected to rivers. The Valley's geography is complex, and short-term drainage fixes won't solve the problem."
He advocates for long-term solutions - preserving open spaces, restoring ponds and lakes, and harvesting rainwater. "We need spaces where rain can naturally seep into the ground. Without that, even moderate rain will send water rushing into rivers and low-lying areas, overwhelming them and causing repeated flooding."
Meanwhile, the Department of Hydrology and Meteorology (DHM) has forecast more rain. Kathmandu Valley is expected to receive light to moderate rainfall in the next 24 hours, similar to several other provinces - Koshi, Madhesh, Bagmati, Gandaki, and Lumbini - with scattered showers likely in Karnali and Sudurpaschim as well.
Today's forecast mentions partly to generally cloudy skies in the Valley, with brief rain or thundershowers in the afternoon (40% chance) and a 20% chance of rainfall continuing into the night.
According to DHM data from 2:41 pm on Tuesday, Budhanilkantha station recorded 32.4 mm of rain in 24 hours, Panipokhari 46.6 mm, and Sundarijal 52 mm.
While these figures may not seem extreme on paper, on the ground they translate to flooded streets, stranded commuters, and hours of traffic gridlock.
The DHM attributes the current weather pattern to westerly and local winds, along with moisture-laden air from the Bay of Bengal and the Arabian Sea.
Nepal's monsoon typically begins in June and ends by mid-September. But if the early signs are any indication, Kathmandu Valley could be in for another waterlogged, flood-prone monsoon season.
