USGS Photo, looking north, at what remained of Lake Waiau on September 26, 2013. The water area was just 15 meters (yards) wide at this time. Prior to 2010, the lake occupied the entirety of the now-dry lake bed, which is about 100 meters (yards) wide. The astronomical telescopes at the summit off Mauna Kea are visible on the skyline.
MAUNA KEA, Hawaii - Lake Waiau, the tiny lake that sits at 13,000 ft. above sea level near the summit of Mauna Kea on Hawaii Island, is almost entirely gone.
The Aloha State’s only alpine lake has been shrinking at an “alarming” rate since 2010, say scientists with the United State Geological Survey. Rangers with the Office of Mauna Kea Management, working with the Department of Land and Natural Resources’s Division of Forestry and Wildlife – which manages the Mauna Kea Ice Age Natural Area Reserve where the lake is located – have been monitoring the lake closely and have tracked this remarkable reduction in the lake size with repeat photography. The changes have also been documented by cultural practitioners and environmentalists. The images of the unique lake slowly disappearing have been startling to long time visitors to the top of the mountain.
In its weekly Volcano Watch article, scientists with the USGS Hawaiian Volcano Observatory discuss the vanishing lake, reporting that they have recently been watching these changes, as well. After all, Mauna Kea was once an active volcano.
“The results are compelling. Prior to 2010, the lake surface area fluctuated between about 5,000 and 7,000 m2 (1.2-1.7 acres), with the variability presumably due to recharge from winter storms balanced by loss due to evaporation. Sometime in early 2010, however, the lake surface area began to shrink and, by late September 2013, had declined to just 115 m2 (0.03 acres) – that is, about 2% of its normal surface area.
Geography professor Donna Delparte, formerly of University of Hawai`i at Hilo and now at Idaho State University, has also been monitoring the recent changes. Her group has made detailed measurements of lake geometry using advanced techniques, such as laser scanning and photogrammetry. Prior to 2010, the maximum depth of the lake was about 3 m (yards), but today the lake is less than 30 cm (1 foot) deep. This means that the current volume of the lake is less than 1% of its normal (pre-2010) value.
Using air photos to extend the time series of lake surface area back to the 1950s, we see no other drops of such scale. Historical photographs taken through the last hundred years, and written reports going back to the early 1800s, give no indication of the lake ever being as small as it is today. This suggests that the current reduction in size is unprecedented in modern times, but we cannot say this with absolute certainty, because there were large time gaps between the recorded observations in the 1800s and early 1900s. Nevertheless, the reduction in lake size that we see today appears to be highly unusual. ”
Some Native Hawaiians who frequent Mauna Kea and feel spiritually connected to the sacred mountain have wondered if the shrinking lake is a sign that the mountain is in peril. Many of the practitioners who visit the lake oppose the development of the summit for astronomy purposes. Pua Case and her ohana have been visiting the lake on a near monthly basis, photographing the changes and posting to Facebook.
A September photo shows Pua Case and her cousin Kanoe, who is seen kneeling by the vanishing lake with spring water brought from Hilo, a gesture to “start to refill the lake”.
In one message, Case wrote:
|words written by my cousin Kanoe that I too believe in and will stand by, words of truth:Extreme decrease of our waters upon our Mauna, at lake Waiau, began in 2010. In three years time it has been rapidly dissipating, disappearing. Revelation was given that our kupuna who reside there would be leaving for there is no way that the spirits can dwell in this kind of capacity of overwhelming development. I believe in our kupuna, I believe! I will not leave them. We will stand with them until the time comes when they tell us otherwise! Me Ke aloha nui nui!Perhaps All will be restored when the mauna is in balance once again! I have much hope and I believe!
The USGS is considering the shrinking lake as a symptom of a another change on the mountain.
“An obvious culprit would be the ongoing drought in Hawai`i that began in 2008. The Mauna Kea visitor center weather station shows very little precipitation for several consecutive months in early 2010, which may have been a trigger for the level drop that was sustained by low precipitation over the subsequent few years. The National Drought Mitigation Center shows that the drought across Hawai`i intensified in early 2010, consistent with this local weather data.
Could other factors be contributing to the potentially unprecedented nature of these changes? Lake Waiau is a “perched” water body, in which water is held in a depression by an impermeable substrate. This substrate consists of layers of silty clay, interbedded with ash layers, and it has been proposed that permafrost also underlies the lake.
It has also been proposed that permafrost surrounds the lake and provides a catchment that directs water into the lake. Could changes in the presumed permafrost have altered the water balance in the lake over the past few years? So far, there is no hard evidence to support this possibility, but we cannot yet count it out. We simply don’t know at this point, and more research needs to be done.”
The USGS asks that if you have historical photos of the lake that you are willing to share, please contact HVO (askHVO@usgs.gov).
“Given its cultural significance and its uniqueness, the disappearance of Lake Waiau would be a great loss for Hawai`i. The future is far from certain for Lake Waiau, and DLNR, rangers, and scientists will continue to watch this situation closely.”