Rapid Shrinkage of Alpine Lake Worries Resource Managers

posted in: January 2012 | 0

Mauna Kea’s Lake Waiau, considered by native Hawaiians to be a portal to the spirit world, seems to be disappearing.

The water level has dropped radically in recent months, and with high elevation temperatures in Hawai`i increasing three times faster than those at lower elevations, evaporation is a likely explanation, says Lisa Hadway, head of the Big Island branch of the Natural Area Reserves System.

In wet years, the lake spans just under two acres and is about 10 feet deep. On average, the depth is about half that, but in dry times, it’s been as low as half a meter. Although the water level has fluctuated greatly with climate changes, the recent decline has been unusually rapid and severe.

“This is extremely alarming,” Hadway told the NARS Commission in November as she showed them pictures of a once-submerged spring that, during the contraction over the past few months, has become exposed.

Located 13,020 feet above sea level, the lake lies within the Mauna Kea Ice Age NAR and is the highest alpine lake in the Pacific.

The shrinkage has garnered increased scientific interest in the lake and researchers will likely be seeking state permits to study the phenomenon, Hadway said.

While some believe permafrost maintains the lake, there is speculation also that it is perched on an impermeable layer of ash. Hadway, who noted that an El Niño event caused the lake’s water level to drop in the 1970s, told the commission, “My sense is it’s evaporating.”

“It’s perched on something. If you lose it, no rainfall in the world will keep it there,” said NARS Commissioner John Stinton, a geologist.

In any case, “Somebody better start studying it pretty soon,” commissioner Pat Conant added.

Teresa Dawson

Volume 22, Number 7 — January 2012

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