The last month of the dry season was emphatically so for the windward Big Island, and the National Weather Service’s only official rain gauge to measure rainfall in double-digits in September was in Kona’s coffee belt, which experiences its rainy season in the summer.
”That’s kind of unusual,” said Kevin Kodama, senior service hydrologist for the NWS in Honolulu. “The east side went to severe drought, mainly because of stream flow and low rainfall. A lot of gauges in the South Hilo and Puna districts had their lowest September totals since 2010, more than a decade ago.
“You’re talking about less than 50% of normal.”
In fact, Hilo International Airport hosts the only official gauge in a populated East Hawaii area that recorded more than half its usual rainfall in September — and just barely, with 4.65 inches of rain, or 53% its average.
Meanwhile, upslope gauges at Piihonua, Waiakea Uka, Waiakea Experimental Station and Mountain View all received less than 5 inches of rain last month, less than 40% of the monthly norms for all four locations.
The aridity has left East Hawaii’s farmers feeling the pinch.
Gordon Inouye, a commercial orchid grower and president of Puna Flower Power, said his Keaau greenhouses — which are dependent upon rain catchment — are “hanging on.”
“We’re monitoring our water levels very, very closely, and we do whatever we can to conserve water,” he said. “And when we get a little bit low, we start to ration the irrigation we’re using with our plants. And if it gets too low, we call a water truck, and we buy water. That’s expensive.”
In contrast, three of the four Kona coffee belt gauges experienced above average rainfall, with Kainaliu and Kealakekua reporting 9.82 inches and 9.55 inches, respectively — more than 30% more rain than in an average September. And Waiaha was the Big Island’s wettest spot, with 11.34 inches of rain, more than twice its usual September.
“A lot of that was in one day. They had a heavy rain event,” Kodama said, referring to Sept. 25, when 4.73 inches of rain fell.
The fourth gauge, in Honaunau, tallied 6.83 inches, just slightly less than average.
Kodama said much of the leeward rainfall has been sporadic, but it fell on places that are usually bone dry.
“The rainfall has been getting up into Puu Waawaa and Puuanahulu,” he said. “And then for a long time, Waikoloa was dry, but they’ve been picking up some rain. Even Kawaihae got some rain. It’s not been a smooth pattern, though. It’s been kind of hit or miss, here and there.
“These pockets have been getting, I think, mainly afternoon rainfall.”
It may not sound like much, but Puuanahulu’s 3.04 inches was 27% above its norm. And Waikoloa received 1.57 inches, about 50% higher than usual.
Neither Ellison Onizuka Kona International Airport at Keahole nor Kaloko-Honokohau National Historical Park shared in the rainfall bounty, however, with 0.43 inches and 0.35 inches, respectively — the latter receiving just 19% of its September norm.
Most spots in Ka‘u reported slightly below average rainfall last month, but South Point received only 0.27 inches, just 11% of its monthly average.
Kohala was mostly dry, as well, with most gauges reporting less than an inch.
And although October is the start of the rainy season in East Hawaii, Kodama said he doesn’t see any immediate relief.
That leaves farmer like Inouye investigating alternative methods of obtaining water.
“We’ve been aware of the water situation, and we’ve been desperately trying to find (funding) to drill a well, since there’s a substantial amount of groundwater here,” he said. “But we couldn’t get it through the Legislature; we couldn’t find any federal grants. But that would definitely be helpful, not only for ourselves, but for the ranch that’s east of us and for the banana crop that’s just adjacent to it.
“So, we’re looking for a source of water and for a well to support our agriculture.”
Email John Burnett at jburnett@hawaiitribune-herald.com.
