Bhutan's hydrology is dominated by rapid, glacier-fed rivers that flow southward through deep valleys into the Brahmaputra River in India.
* **Major Rivers (Chhus):** The primary river systems include the Drangme Chhu (the largest basin), the Puna Tsang Chhu (Sankosh River), the Wang Chhu, and the Torsa Chhu. * **Glacial Lakes:** The high Himalayas in northern Bhutan are dotted with thousands of glacial lakes, such as Thorthormi Tsho and Lugge Tsho. These are breathtakingly beautiful but also carefully monitored due to the risk of Glacial Lake Outburst Floods (GLOFs) caused by climate change.