Lake Waiau’s water levels remain robust, the state Department of Land and Natural Resources reports.
The alpine lake, situated in Puuwaiau cinder cone more than 13,000 feet above sea-level, was full as of mid-month, the department said in an update. The rangers, along with the DLNR’s Division of Forestry and Wildlife, continuously monitor the sacred site atop Maunakea.
Lake Waiau has now been full or nearly full since fall-winter 2014, a stark contrast to 2012-13 when the high-elevation lake was shrinking fast due to years of drought. Water had started receding in 2010 and by the end of 2013, there was just a puddle in the lake’s center.
While the lake is normally 100 yards wide, the U.S. Geological Survey reported it was just 10 yards wide and 9 inches deep on Sept. 26, 2013. By December, the lake’s maximum depth measured just 5 inches.
When full, the lake has a maximum depth around 10 feet, according to photographic monitoring and data of Lake Waiau kept by state agencies since 2012.
Lake Waiau is a “perched” water body in which water is held in a depression by a continuous layer of fine material in its surroundings, which is covered by periglacial slope deposits. The fine layer acts as an aquifer that may gently release water into the lake over the year, according to a 2016 report by Matthias Leopold and Norbert Schorghofer, the most recent research released on the lake.
According to the Department of Land and Natural Resources, the color of the water is a function of naturally occurring biological activity, mostly diatoms and algae. The darker or bluer colors are most noticeable after winters (cooler periods) with substantial water inputs (dilution).
As the summer progresses, according to the department, the diatoms and algae grows as the water warms and extracts energy from the sun, the lake will most likely slowly turn green again. September is the period of peak productivity and thus close to the peak in green color — although every year is different.