The first six months of 2010 were the driest in the 90 years that Ulupalakua Ranch has been measuring rainfall.
Rancher Sumner Erdman, president of Ulupalakua Ranch, said Tuesday that the total rainfall for the year is 37 percent of normal. He’s been selling stock and moving cattle off the Upcountry Ranch to other ranches.
The ranch might be eligible for some drought disaster relief loans from the Department of Agriculture, but he’s been too busy to start to apply. “We’re in complete disaster-control mode,” he said.
Erdman said the dry weather has cost his business “pretty good into six digits” this year.
Ulupalakua is on the dry side of the island, but 4.04 inches from January to June was extraordinary.
The wet side of the island isn’t doing much better. At the West Wailuaiki rain gauge, which is the principal point for measuring rainfall in the East Maui watershed, there was exactly one day between late March and the end of July when more than 1 inch of rain fell. This is supposed to be one of the wettest places on Earth.
“It’s dry, dry, dry,” said Stephen Gingerich of the U.S. Geological Survey in Honolulu after releasing the latest quarterly summary, through June.
West Wailuaiki recorded 9.09 inches in June, which was 89 percent of normal for the month, and for January-June it received 96.20 inches, which is 93 percent of normal. But no other gauge in the county had as much as 80 percent of normal amounts, and several are around 20 percent of normal.
Lahainaluna was exceptional, with 0.70 inches through June, just 6 percent of normal.
Puu Kukui, atop the West Maui Mountains, is the wettest place on Maui and received the second-highest amount of rain in the state in the first six months, 106.38 inches. However, that was only 53 percent of average.
“It seems like I’ve been saying Puu Kukui is 50 percent of normal for at least a year,” Gingerich said, and the dry spell now stretches back at least four or five years.
Gingerich said he “can’t really say,” because he hasn’t done a scientific study, whether the recent decrease in rainfall is just another low point in the sometimes decades-long swings of island climate or some indication of an abnormal trend change.
It’s statewide, “but Maui seems to have gotten it worse,” he said.
The USGS Drought Monitor has five levels: abnormal, moderate, severe, extreme and exceptional drought.
All of Hawaii is at least abnormally dry. Lanai is severely dry. About three-quarters of Molokai is extremely dry, as is the coastal part of West and South Maui.
Kawaihae and Kau on the Big Island, the driest parts of the state in the best of times, are suffering exceptional drought. No part of Maui is that dry, but more than half the county is extremely dry.
A National Weather Service method of assessing moisture is called the Standardized Precipitation Index. Values around 1.0 are normal, and values over 2.0 are extremely wet, while values beyond -2.0 are extremely dry.
For the past 12 months, Ulupalakua has a value of -1.67. Opihihale on the Big Island is at -3.02, but Ulupalakua is otherwise the driest station in the state.
Hana is the only station on Maui that does not sink below -.1.0, and it is at -0.95.
Other stations are Kahului, -1.33; and Kula, -1.39. Molokai is at -0.86, but Lanai is not in the report.
August brought the first real rain to much of Upcountry in months, and the Wailoa Ditch, source of most of Upcountry’s drinking water, briefly spiked to 130 million gallons per day Monday and Tuesday. However, during the previous week, flows were in the 50-mgd range. That is above the crisis level of around 20 mgd, but storage levels are low with at least three months of dry weather ahead.
The 50-mg Piiholo Reservoir, which had held 36 mg, was nearly full after the rain. The 100-mg Kahakapao reservoirs held only about 40 mg before the rain, though they had built up to nearly 50 mg by Tuesday.
Upcountry is under a drought watch, and users are asked to cut consumption by 5 percent, although mandatory reductions are not imposed.
Demand has been running between 9.3 mgd and 10 mgd, which is above the Department of Water Supply’s goal of keeping usage down to 9 mgd.
The Geological Survey monitors withdrawals in the Iao-Waihee aquifers, which supply most of the water for Central and South Maui.
The 12-month rolling average of withdrawals from Iao through March was 15.22 mgd, almost the same as the year before. The 12-month rolling average for Waihee was 5.8 mgd through March, about 400,000 gallons per day more than a year earlier.