The Hanalei River on the island of Kauaʻi in Hawaii flows north from the eastern slopes of Mount Waiʻaleʻale for 15.7 miles (25.3 km) until it reaches the Pacific Ocean at Hanalei Bay as an estuary. With a long-term mean discharge of 216 cubic feet (6.12 cubic meters) per second, in terms of water flow it is the second-largest river in the state; although its watershed of 19.1 square miles (49 km2) is only sixth-largest on Kauaʻi, it encompasses areas of the highest recorded rainfall on the planet and plunges precipitously from its headwaters at 3,500 feet (1,100 m) above sea level.