An interactive map that brings Bengaluru’s stormwater to life. Explore the different layers that make our watershed – the city’s topography, valleys, tanks and drainage.
Bengaluru’s stormwater infrastructure is hidden beneath our feet and along our roadsides—a complex network of drains, tanks, and rajakaluves that has evolved over centuries.
Use this tool to decode how water moves through your neighbourhood and discover the forgotten networks that once sustained the city.
Project
Building a Resilient Bengaluru
Year
2025
What We Did
Research & Documentation, Tool Design
Status
Completed
Understand how the city’s elevation shapes the flow of stormwater
Zoom out of the city and trace the flow of water from our valleys to the Bay of Bengal
We know of the tanks that exist today. But where are our tanks that have been lost over the centuries?
Trace the primary and secondary drains that carry our stormwater run off.
Upload your own layers. Download our layers.
Explore how our sewage infrastructure overlaps with our drainage
What is next to our drains? Explore our typology library and analysis
What can you find on the map?
Understand how the city’s terrain shapes the way water flows. Explore our watershed. Find the lost tanks of Bengaluru and what their status is today. Understand how our sewage and stormwater infrastructure overlap. Analyse where the city’s flood hotspots are located – and much more.
| Group | What it shows |
|---|---|
| Primary Drains | Primary stormwater drain network |
| Secondary Drains | Secondary drain network |
| Existing Tanks | Current lakes/tanks |
| Lost Tanks | Tanks lost after 2000 |
| Tanks 1700 | Tank network as of the 1700s |
| Tanks 1800 | Tank network as of the 1800s (lost and existing) |
| Tanks 1900 | Tank network as of the 1900s (lost and existing) |
| Flood Hotspots | Known flood-prone locations |
| BWSSB Sewer Lines | Underground sewer network (300mm+ and less) |
| Valleys | Valley boundaries |
| Valley Categories | Colour-coded valley types |
| Sub Valleys | Sub-valley boundaries |
| Watershed | Strahler stream order / watershed |
| Greens | Parks and wetlands |
| Boundaries | GBA boundary and ward boundaries |
| Background | Satellite, roads, place labels, DEM, hillshade, Carto basemap |
| Typologies | Drain typology analysis layer (LHS/RHS side coding) |
Explore the Typology Library
Stormwater drains in Bengaluru run through a diverse range of urban conditions—cutting across built-up areas, roads, private plots, parkland, and open spaces. The library breaks down the different typologies so you can see how the city’s terrain, land use, and development patterns interact with its stormwater system.
Watch the Tutorial Video
Built in the Open
The Bengaluru Ecology Map’s interface and interactive logic are open source -the full front-end code is publicly available on GitHub, including how layers are toggled, how features are filtered, and how the drain typology diagrams are matched and displayed.
The map itself is powered by Mapbox, using a custom-designed style that brings together stormwater drains, lake and tank networks (current and historical), valley boundaries, watershed data, sewer lines, and terrain – layered into a single interactive view of the city’s water systems.
What’s open: the codebase – how the map is built, how layers are organized, and how users can explore the data – is freely available for anyone to study, reuse, or adapt for their own civic or research projects.
