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The Honolulu Advertiser

Posted at 12:59 p.m., Monday, January 21, 2008

Water reserves on Maui drop; conservation urged

By EDWIN TANJI
The Maui News

WAILUKU — Demand on Maui County water supplies over the past week remained well below average for January, but clearing skies also reduced the available water in surface water systems.

Water Director Jeff Eng reported that damp weather over the past week helped to keep consumption down by reducing the need for water on lawns and outdoor plants, according to The Maui News. But he urged consumers to turn their attention to how they are using water inside their homes to develop water-conservation practices that can carry over through the dry season.

In a related report, the National Weather Service noted that 2007 ended with nearly normal rainfall at several sites, largely as a result of the deluge received during the Dec. 5 Kona storm that swept over the islands. But key watersheds remained below normal.

On the Central Maui and Upcountry water systems, consumption during the period of Jan. 10 to Wednesday was up slightly from the previous week, although use in both systems remained well below demand recorded in January 2007.

"Water production for the week of January 10 to January 16 remained steady from the previous week," Eng said. "The cooler and wetter weather of this time of year lessens our outdoor water demands.

"Now is the time for us to focus on our indoor water-use practices. Learn to take shorter showers; do not allow faucets to run; and minimize the number of loads of laundry," he said. "Water-conservation practices that we focus on now will help get us through the high water demands of next spring and summer."

Data from water department and National Weather Service sources indicate that Maui County is seeing sharp spikes and dips in rainfall that affect how much water is available in the county's water sources.

After Upcountry reservoirs filled up from heavy rains and lower demands in December, rainfall on the East Maui watershed has tapered off to below-normal levels over the past week. Even with Upcountry water demand at a low level, the reservoirs that held 166 million gallons on Jan. 7 were down to 150 million gallons two weeks later. On Wednesday, the Wailoa Ditch that supplies water to the county's Kamole Weir treatment plant was flowing at 93.1 million gallons a day, after falling steadily from 161 mgd on Jan. 7. The ditch has a capacity of 200 mgd.

In its preliminary daily rainfall records, the National Weather Service reported below-normal rain in both the East Maui and West Maui watersheds since the beginning of 2008.

Over the first half of January, through Friday, the West Wailua Iki rain gauge showed 7.91 inches of rain, most of it occurring over the first three days of the year when 4.75 inches fell. The East Maui rain gauge receives an average of 16.54 inches in January.

For the same period, the Puu Kukui gauge showed 6.81 inches. Puu Kukui — rated the second-wettest spot in the islands at 387 inches a year — averages 30 inches of rain in January.

Through the year 2007, Puu Kukui recorded just 61 percent of normal rainfall – 234.65 inches of the norm. West Wailua Iki was also below normal for the year with 184.92 inches, compared to the norm of 205.3 inches.

Both watersheds and all other areas of the county recorded above-average rainfall in December, but the torrential rains brought in by the Kona storm in early December did not fully offset lower-than-normal rainfall for the year, particularly in windward areas of the island.

In addition to West Wailua Iki and Puu Kukui, areas recording less-than-normal rainfall for the year included:

  • Kahului, 70 percent of normal, with 13.13 inches. Half of the total, 6.88 inches, was recorded in December.

  • Wailuku, 86 percent of normal, at 24.21 inches, with 11.71 inches falling in December.

  • Haiku, 66 percent of normal, with 42.76 inches.

  • Hana, 70 percent of normal, with 55.82 inches.

    Conversely, normally drier leeward areas ended the year with normal rainfall totals, including:

  • Kula, 106 percent, with 23.61 inches; with 11.2 inches recorded in December.

  • Ulupalakua, 106 percent, with 32.59 inches; 12.78 inches in December.

  • Kaupo Gap, 108 percent, with 98.3 inches; 41.10 inches in December.

  • Kahoolawe, 107 percent, with 24.74 inches; 11.25 inches in December.

    According to the monthly rainfall report prepared by weather service hydrologist Kevin Kodama, the December Kona storm impacted Maui and the Big Island most, with some sites believed to have received 10 to 15 inches in a single day, based on radar analysis. He said the radar data indicate more than 10 inches fell in the Polipoli-Keokea area Dec. 5, when runoff flooded homes in Kula and Kihei.

    The frontal system moved across the islands beginning on Dec. 4 and stalled as it approached Maui County, cutting the winds but keeping the moist air over Maui and the Big Island.

    "Maui County and the Big Island saw the heaviest rains with several sites recording event totals in the 10- to 15-inch range, and isolated spots recording higher amounts," Kodama said in his report.

    He noted that an upper-level trough approached the islands on Dec. 30, bringing less-severe rainfall conditions but causing flooding on Oahu and on Molokai on New Year's Eve.

    For the month of December, Kodama noted that Puu Kukui recorded the highest rainfall total of any area of the state with 60.22 inches, and several other Maui County gauges had record rainfall for the month. Lanai City with 17.12 inches and Mahinahina with 20.12 inches were the highest monthly totals recorded since 1991.

    "As if trying to make up for missed rainfall earlier in the year, Maui County experienced the wettest conditions statewide during December with most sites posting well above normal totals," he said.

    AVERAGE DAILY WATER USE

    District/Jan. 10-16/Jan. 3-9/January 2007

    Central Maui 22.48 mgd 21.75 mgd 23.88 mgd

    Upcountry 5.79 mgd 5.66 mgd 7.67 mgd

    Lahaina 5.38 mgd 5.83 mgd 5.92 mgd

    Hana 0.27 mgd 0.30 mgd 0.29 mgd

    Molokai 0.96 mgd 0.96 mgd 1.12 mgd

    Total 34.88 mgd 34.50 mgd 38.88 mgd

    For more Maui news, visit The Maui News.