Rivers & Roots

Kathmandu was a sponge city before the term existed.

Today, cities around the world are trying to move away from the “drain-and-discharge” model, where rainwater is quickly pushed into pipes, drains, and rivers.

The newer idea is simple: capture rain where it falls, slow it down, let the ground absorb it, and recharge groundwater.

But this is not new to the Kathmandu Valley.

For centuries, traditional courtyards, brick-paved alleys, pukhu ponds, rajkulos, and hitis worked together as one living water system.

The ponds stored monsoon rain.
The permeable surfaces allowed water to soak into the ground.
The rajkulos moved water across the valley.
The hitis released filtered groundwater back to communities.

This was not just beautiful architecture.

It was climate infrastructure.

But as recharge zones were paved with concrete, rajkulos were cut by roads, and groundwater was extracted faster than it could recover, Kathmandu began facing two crises at once: flooding during the monsoon and water scarcity during the dry season.

The solution may not be to copy the past exactly.

It may be to learn from it.

From GPR mapping of ancient water channels in Patan to community-led hiti restorations in Lalitpur, Kirtipur, and Godawari, Nepal is already showing how traditional systems can be adapted for modern resilience.

The future of Kathmandu’s water may be hidden in the wisdom of its own streets.

Follow Rivers & Roots for more stories on Nepal’s built environment, water systems, and climate resilience.

What if festivals weren't just celebrations...

What if they were also infrastructure maintenance plans?

For over a thousand years, the Newar community has celebrated **Sithi Nakha**—a festival that ensured Kathmandu's ancient Hiti water system was cleaned and maintained before the monsoon arrived.

At the driest time of the year, entire neighborhoods came together to remove silt from ponds, wells, and stone spouts. Local beliefs about the Nagas, the guardians of water, transformed this annual maintenance into a sacred responsibility passed down through generations.

Even the four-day waiting period after cleaning had a practical purpose: allowing sediments to settle and the natural biological filtration system to recover before the water was used again.

This is a powerful reminder that great infrastructure isn't just built.

It's maintained.

And sometimes the greatest engineering isn't found in stone or brick—it's found in culture.

What modern systems do you think could benefit from this kind of community stewardship?

Follow **** for more stories exploring Nepal's ancient engineering, indigenous knowledge, and the timeless ideas that can help build a more sustainable future.

Kathmandu’s hitis were not just stone spouts.

They were part of a carefully designed underground water system that cleaned water long before modern filters existed.

As rainwater moved from ponds into the shallow aquifer, it passed through layers of gravel, sand, charcoal, and even lapsi seed stones.

Each layer had a role.

Gravel slowed the flow and trapped larger particles.

Fine sand helped remove smaller debris and supported a living biological layer that broke down organic matter.

Charcoal absorbed odors, toxins, and dissolved impurities.

And lapsi seed stones, an indigenous Nepali innovation, may have helped bind heavy metals through their porous carbon structure.

What looks like ancient infrastructure was actually advanced passive filtration.

The lesson is simple: Nepal’s traditional water systems were not primitive. They were deeply scientific, climate-adapted, and rooted in local materials.

As cities look for sustainable water solutions today, maybe the future is not only about inventing something new.

Maybe it is also about remembering what already worked.

Follow Rivers & Roots for more stories on Nepal’s built environment, water systems, and climate resilience.

Your climate footprint starts with the way you live: your home, transport, food, energy and everyday choices.

Aptech Lab, a women-led climate firm in Nepal, is introducing Nepal’s first Climate Checkup tool, built around our context, our lifestyles and our future. In collaboration with Rivers and Roots, we’re helping take this tool to more people and support their goal of making 0.1% of Nepal’s population climate conscious by 2027.

This is not about guilt. It is about awareness, climate literacy and understanding where we stand as Nepal continues to face the growing impacts of climate change.

What’s your number? Take the Climate Checkup.

RiversAndRoots AptechLab

Kathmandu Valley’s ancient water system was not just a collection of ponds and stone spouts.

It was an engineered network.

Rajkulo canals carried water from rivers at the valley’s edge.
Pukhu ponds stored and recharged groundwater.
Hitis brought that water back to people through carved stone spouts.

Long before modern drainage and piped systems, the valley used gravity, aquifers, clay pipes, ponds, and public courtyards to manage water across seasons.

This was not just infrastructure.
It was culture, ecology, engineering, and public life working together.

As our cities face water stress, flooding, and groundwater decline, maybe the future is not only about inventing new systems.

Maybe it is also about remembering the ones we already had.

One year of growth, green, and giving back! 🍅

​A year ago, we set out to transform a bare rooftop into a productive green space to help cool the city and fight the urban heat island effect. Fast forward to today, and the results have completely blown us away! 🏙️🌱

​By using the square-foot gardening method, we maximized every inch of space for food production. In just 12 months, our trees are thriving and we’ve harvested an amazing bounty of fresh, homegrown veggies: okra, tomatoes, beans, cucumbers, carrots, beetroot, peas, and spinach! 🥕🥒🥗

​But the best part? We’ve created a thriving micro-ecosystem. Our little urban oasis is now buzzing with life, bringing back beautiful birds and essential pollinators like bees. 🐝🐦
​Ready to transform your own unused space into a productive green sanctuary? Let’s make it happen! Send us a DM to learn how we can help upgrade your rooftop. 🌿👇

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