Traversing the state of Karnataka in peninsular India, from the coconut-shaded coastline, through the spectacular Sahyadri mountain range, towards the vast Deccan Plateau, one encounters a fascinating range of hydrological conditions. The Sahyadris, or Western Ghats, running close to the western coast, not only forms a natural hydro-climatic divide, but is also a complex vegetated landscape of rich forests intermingled with diverse agro-ecosystems in its valleys and slopes. Heavy monsoon rains in this densely vegetated Sahyadri ridge is the primary ‘source’ of water for all the major rivers—both east- and west-flowing—and a lifeline to more than a quarter of a billion people in peninsular India. The west-flowing rivers are short but gushing, creating a water-rich coastal area before joining the Arabian Sea. On the other hand, the east-flowing rivers are long and slow, meandering across the much drier Deccan Plateau of Karnataka, and then Telangana, Andhra Pradesh, or Tamil