Hydrology of Bengaluru Urban District

Understanding the Map

This map shows Bengaluru Urban district and its five taluks across an area of 2196 sq Kms. It highlights the district’s rivers, lakes (tanks), and rajakaluves (stormwater drains), overlaid on the city’s topography (elevation). Together, these layers reveal how the shape of the land influences the natural movement of water through the district.

(Elevation data: Shuttle Radar Topography Mission (SRTM), United States Geological Survey.)

Understanding Bengaluru’s Hydrology

A prominent drainage divide runs through the centre of Bengaluru, separating the district into two major river basins. To the west lies the Arkavathi River Basin covering about 46% of the district, while the Dakshina Pinakini River Basin occupies the remaining 54% to the east.

The district’s elevation ranges from approximately 700 to 970 metres above mean sea level. Rainfall follows this natural topography, flowing downhill through streams and rivers before eventually joining the Cauvery or the Ponnaiyar (South Pennar) river systems. This landscape has shaped Bengaluru’s hydrology for centuries determining where rivers flow, lakes were constructed and groundwater is recharged.

A River basin simply explained

Think of a river basin as a giant bowl in the landscape. When it rains, water flows downhill and finds its way into streams and rivers. All the land that drains towards the same river and its tributaries makes up its river basin.

The higher ground around the basin forms its boundary. Rain falling on one side flows towards one river system while rain falling on the other side can flow towards another. This is called a drainage divide.

Bengaluru sits across such a divide. Rain falling to the west drains towards the Arkavathi while rain falling to the east drains towards the Dakshina Pinakini.

Why does understanding Bengaluru’s hydrology matter?

Bengaluru’s hydrology is defined by the natural relationship between its topography, rivers, lakes, and groundwater. While urban infrastructure has transformed many streams into stormwater drains and altered natural flow paths, the underlying landscape continues to govern how water moves across the city. Understanding this natural hydrology is essential for planning our city expansion better, restoring rivers, managing floods, recharging groundwater and building a more water-secure Bengaluru.

Keep exploring

Explore the larger Cauvery River system or dive deeper into Bengaluru’s waterscapes and the rivers that flow through the city.

Explore the Cauvery River Basin

Get to know the Cauvery and its tributaries, the landscapes that sustain them, and what is changing across the river basin.

Explore the Arkavathi River System

Explore the Arkavathi, its tributaries, reservoirs and wider landscape through detailed maps, data, studies and stories.