KAILUA-KONA — Lake Waiau’s water levels remain robust almost five years after it nearly disappeared amid years of drought.
The alpine lake, situated in Puuwaiau cinder cone more than 13,000 feet above sea-level, was full as of Tuesday, Dan Dennison, senior communications manager for the state Department of Land and Natural Resources, said Thursday.
Water quality also seemed “above average to the eye,” he said. That was clearly evidenced in recent photos captured by rangers with the Office of Maunakea Management, showing a robust, clear blue lake. 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 fall-winter 2013 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.
Leading up to the near-loss of the lake in 2013, the closest rain gauge, situated at Hale Pohaku at 9,200 feet in elevation, had recorded near to well-below average rainfall since 2005. The long-term average at Hale Pohaku is 25.18 inches, according to National Weather Service Senior Hydrologist Kevin Kodama.
From 2014 to 2016, the gauge measured near to above average rainfall, according to Kodama. Last year, rainfall was somewhat below average.
Kodama said because some data is missing for this year, it’s hard to say with certainty if rainfall is up or down. However, based on data collected for January and April as well as looking at how wet Hawaii Island was between February and April, it can surmised that rainfall at Hale Pohaku through April was near to above average, he said.
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.