The Jichu Drake and Jomolhari glaciers at an altitude of about 4,300 m are the main sources of the Paro Chhu River in the Jigme Dorji National Park. The Paro Chhu flows southeast of the city of Paro at an altitude of about 2,300 m into the Thimphu Chhu and is called the Wong Chhu, which is also known as the Raidāk River in its lower reaches. This river is a tributary of the mighty mountain stream Brahmaputra.