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Every monsoon, Kathmandu forgets the havoc of the previous year. It forgets flooded intersections, the brown water pouring into homes, the children wading to school. And each year, after warnings from our Department of Hydrology and Meteorology, the city braces again—for rainstorms that turn streets into rivers and commuters into reluctant swimmers.
This isn’t a natural disaster. It’s an infrastructure failure compounded by climate change, ignored planning data, outdated sewer systems, and political dysfunction.
I’m an environmental engineer specializing in stormwater modeling, drainage planning, and flood mitigation. Reviewing Kathmandu’s detailed project reports reveals a grim pattern: design assumptions based on outdated rainfall data, nonexistent digital records, undersized pipes, and canals that clog at the first sign of rain.
Take the Kharibot–Dhungedhara sewer upgrade, intended as a resilience model but now mired in a bureaucratic turf war between the Kathmandu Valley Development Authority (KVDA) and Kathmandu Metropolitan City (KMC). Meanwhile, the 5-meter-wide canal it aims to replace along the Ring Road is choked with plastic, silt, and neglect, routinely overflowing during heavy rains.
The problem is structural—both literally and institutionally. Kathmandu’s green spaces shrink as hillsides give way to concrete homes without runoff planning. Nature’s drainage has been replaced by narrow, aging pipes that fail under moderate rainfall.
One person dies after drowning in a pond in Bhaktapur
To worsen matters, planning relies on outdated data. The 2022 Kharibot–Dhungedhara sewer upgrade study used rainfall records from 1988–2013, ignoring the sharp rise in extreme weather over the last decade. By sidelining climate projections from meteorological agencies, designs are based on a world that no longer exists.
Some might cite resource shortages, yet Kathmandu holds the largest municipal budget in Nepal. While the mayor is an engineer, there remains a shortage of qualified engineers and specialists at ward and KMC urban planning levels. This gap contributes significantly to inadequate design, maintenance, and oversight of the city’s drainage infrastructure.
Even basic engineering principles are ignored. Sewers are built with incorrect slopes, undersized manholes, and an absence of digital "as-built" records essential for maintenance. Critical sub-watersheds remain unmodeled. Construction quality suffers due to corruption. Roads just paved are ripped open weeks later for unauthorized utility work and rushed patch jobs.
Try modeling floods under these conditions: no local rainfall stations, incomplete maps, sewer layouts often scribbled on paper, if documented at all. Even the Detailed Project Report (DPR) for the Kharibot–Dhungedhara sewer section lacked calibration and validation data, despite its proximity to well-known flood-prone areas.
Globally, cities are modernizing drainage in response to climate change. Dallas lost $6 billion to flooding in 2022, Italy’s Emilia-Romagna region suffered $11 billion in 2023, and Dubai incurred $3 billion in damages in 2024. Many now update drainage manuals with climate-informed design storms, green infrastructure, and sensor-driven maintenance. Meanwhile, Nepal’s 2021 sewer guidelines—Version 4.0—fall short in incorporating current watershed dynamics, including urbanization, infiltration capacity, and climate-driven extremes.
Updating to Version 5.0 could integrate open-source mapping, enforce digital records, and introduce adaptive sewer modeling like Raleigh, North Carolina. It’s not about copying the West—it’s about acknowledging we’re not exempt from the same weather extremes.
India published urban flooding guidelines over a decade ago. In contrast, Nepal’s National Disaster Risk Reduction and Management Authority (NDRRMA) still develops a comprehensive urban resilience plan, while local governments scramble to react rather than prepare. The so-called “infrastructure ambulance” meant to fix potholes sits broken and idle—just when floods hide hazards like open manholes and deep potholes that cause accidents.
In Thapathali and Nakhu, stormwater funnels through embanked tributaries and narrow culverts, pushing floodwaters, mud, and debris onto downstream neighborhoods along the Bagmati and Bishnumati corridors. Yet, instead of coordinating with Lalitpur municipalities to manage flood risk across the watershed, KMC continues to dig up streams and build roads under the guise of beautification. Research shows isolated stream restoration—without considering downstream flow, land use, or floodplain connections—can worsen flooding. Though cosmetically appealing, such fixes disrupt natural drainage, destabilize flow patterns, and displace flood risk downstream. In a rapidly urbanizing city, this approach is not just ineffective—it’s dangerous.
Meanwhile, New Road—one of the city’s most historic commercial streets—is made to look like a postcard. Perhaps the city hopes a fresh coat of whitewash will distract from crumbling drainage beneath. Or maybe, just maybe, it’s a more photogenic backdrop for the KMC mayor’s PhD dissertation on heritage preservation.
If this trajectory continues, KMC may need to coordinate with the federal department for waterway transportation—Nepal Shipping Office—to provide every household with life jackets and inflatable boats to navigate monsoon-formed inland waterways.
I write not to mock my city but to mourn it. We haven’t forgotten engineering; we’ve replaced it with gimmicks that garner social media likes but offer little in lasting solutions.
(The author is an environmental engineer based in Kathmandu, Nepal. His work focuses on stormwater management, drainage design, and urban flood modeling using optimization algorithms. He specializes in climate adaptation, disaster response, and resilience planning at metropolitan, provincial and national levels. He can be reached at koirala.aparajit@gmail.com.)
