Located on Big island in the " Mauna Kea Ice Age
Natural Area Reserve", the Lake Waiau is under close surveillance since 2010.
Hawaii - Big Island - Mauna Kea as seen from the Mauna Loa Observatory - Photo Nula666
This small lake , located below the summit of Mauna Kea, is the only alpine lake
in Hawaii. Despite its small size , it plays an important role in the
ecology and local culture .
Hawaii - Mauna Kea : Lake Waiau and the outlet stream in May 2005 - photo Karl Magnacca .
The professor of Geography, Donna Delparte previously assigned to the University of Hawaii at Hilo, and currently at the University of Idaho, recorded the recent changes with laser scanning and
photogrammetry
modern techniques. Prior to
2010, the surface of the lake Waiau fluctuated between 5,000 and 7,000 m², with a variability dependent from the recharge in winter by rainfall and snow, and evaporation losses .
Hawaii -
Mauna Kea : the Lake Waiau in January 2012 - Credit photo: Office of Mauna Kea Management
Hawaii - Mauna Kea : the remains of Lake Waiau September 26, 2013 - photo
USGS / HVO
The scale is given by the men, on the lakeside - Note the proximity of the lake and the astronomical settlements.
In early 2010 , its surface began to decrease to as little as 115 m²
in September 2013. Its maximum depth was about 3 meters in 2010 , it is no more than
30 cm. today ... which means that the current volume is less than 1 % of its
normal value.
Examination of historical
photographs taken over the last 100 years gives no indication of a reduction in size as observed today.
What are the factors that explain these unprecedented changes ?
Hawaii drought that
began in 2008 and intensified in 2010 may take place in this lower level , seasonal inputs are less important.
The
situation of " perched lake " of Waiau ( over 4,000 meters) is special : the water is held in a depression by an impermeable substrate, consisting of silty clay layers interbedded with layers of
ash . Permafrost is suspected to underlie
and surround the lake, providing a watershed that directs the water to the lake.
It
is still difficult to support one or another hypothesis : reduced rainfall or changes in permafrost ... unless these variations are related to the activity of the volcano.
Hawaii - Mauna Kea : the remains of Lake Waiau in November
2013 - Photo : Office of Mauna Kea Management
Some native Hawaiians, attending the Mauna Kea and feeling spiritually connected to the sacred mountain, asked whether the decreased level of the lake was not a sign of imminent danger to this
place . Many practitioners are indeed opposed to the
development of astronomical facilities on the summit of the volcano.
Poli `ahu , ice goddess of Mauna Kea
... Pele is well alive in the background - drawing Herb Kane
In the Hawaiian
mythology, Poli `ahu, whose name means " cloaked bosom " , is the legendary girl of Wakea , ancestor of
the Hawaiian . As goddess of snow, it is the antithesis of her rival , the goddess
Pele.
Waiau ,
Poli `ahu sister, the guardian of the lake that bears his name.
She
bathes Poli
`ahu, and refreshes her drinking gourd with sweet water which she can fetch by using her bird form to fly from place to place.
Autel on Puu o Kukahauula , the summit of Mauna Kea. Can be seen in front of the altar on the left ( and inset ) the bench mark of USGS .
- Photo Denys
Sources:
- HVO / Volcano watch – Lake Waiau is shrinking fast - link
- Global Volcanism Program - Mauna Kea
- USGS - The geology and petrology of Mauna Kea Volcano, Hawaii; a study of postshield volcanism - 1997, Wolfe, Edward W & al.
