Lake Waiau Facts for Kids

Quick facts for kids Lake Waiau

Lake Waiau Location in Hawaii Show map of Hawaii Lake Waiau Location in Pacific Ocean Show map of Pacific Ocean
Location	Mauna Kea, Hawaii
Coordinates	19°48′41″N 155°28′39″W / 19.81125°N 155.47743°W / 19.81125; -155.47743
Catchment area	13.5 ha (33 acres)
Basin countries	United States

Max. width	100 m (330 ft)
Surface area	6,000 m² (65,000 sq ft)
Max. depth	2–2.5 m (6.6–8.2 ft)
Surface elevation	3,970 m (13,020 ft)

Lake Waiau is a special lake found high up on Mauna Kea, a big mountain on the island of Hawaiʻi. It sits about 3,970 meters (13,020 feet) above sea level. This makes it one of the highest lakes in the entire United States!

After some other lakes disappeared, Lake Waiau is now the only lake on Hawaiʻi Island. It is also one of the very few lakes in the whole state of Hawaiʻi. The lake is quite small, usually about 100 meters (330 feet) across. Its size changes a lot depending on how much water it has.

When the water level is high, a small stream flows out of the lake. But this stream quickly disappears into the ground nearby. The name "Waiau" means "swirling water" in the Hawaiian language. Even though its name suggests movement, the lake is usually very calm. In winter, it often freezes over. However, small water insects like midges and beetles can still be found living and breeding in its waters.

What is Lake Waiau Like?
How Lake Waiau Shrank and Grew Back
Lake Waiau in Hawaiian Stories
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What is Lake Waiau Like?

Lake Waiau is located inside a small volcanic cone called Pu'u Waiau. This cone is part of the Mauna Kea mountain. The lake is shaped a bit like a heart and is about 100 meters (330 feet) wide.

The lake's surface area is usually around 6,000 square meters (65,000 sq ft). But this size changes a lot throughout the year. It is biggest in the spring, when its deepest point can be between 2 and 2.5 meters (6.6 to 8.2 feet) deep. By the end of summer, the lake often shrinks to only one-third of its spring size. At that time, its deepest point can be less than 1 meter (3.3 feet).

If the lake gets deeper than 2.3 meters (7.5 feet), some water will spill over into a nearby valley called Pohakuloa Gulch. The lake gets all its water from rain and snow, mostly during the winter. The area that collects water for the lake is about 135,000 square meters (33 acres). Most of this area is inside the Pu'u Waiau cinder cone itself.

Lake Waiau is unusual because the ground around it on Mauna Kea usually cannot hold water. Scientists are still trying to figure out why the ground under the lake is able to keep water in. They think it might be a layer of very fine, packed ash, or a special type of basalt rock. It could also be a small layer of frozen ground, called permafrost. While permafrost has not been found right under the lake, it has been found in another part of the Mauna Kea peak area. What we do know is that there is a thick layer of sediment, about 7.5 meters (25 feet) deep, at the bottom of the lake.

How Lake Waiau Shrank and Grew Back

Between 2010 and 2013, Lake Waiau became much smaller. By September 2013, it was just a tiny puddle, less than 2% of its normal size. Scientists were not sure why this happened. They thought it might be because of dry weather (drought) or because a possible permafrost layer under the lake was melting. If permafrost melted, it could cause the water to leak out of the lake faster.

However, after a very wet winter in 2013-2014, the lake started to grow back. By May 2014, it was about 75% of its original size. Soon after, it returned to its normal size. Because of this, scientists now believe that the main reason the lake shrank was the drought conditions on Mauna Kea from 2010 to 2013.

Lake Waiau in Hawaiian Stories

Lake Waiau is important in Hawaiian mythology, which are old stories and beliefs. Besides the snow goddess Poliʻahu, there are two other snow goddesses named Lilinoe and Waiau. These goddesses are linked to Mauna Kea. Some stories say that the lake was named after the goddess Waiau, who used to bathe in it.

Long ago, Hawaiians believed that the entire peak area of Mauna Kea, including Lake Waiau, was a very sacred place. Only priests and chiefs were allowed to visit it. Later, when the Hawaiian kingdom was formed, members of the royal family sometimes visited the peak. The last royal visitor was Queen Emma in 1881. She also took a bath in the lake during her visit.