WAILUKU, Maui — A strong trade wind flow through the past week brought regular, and occasionally heavy, showers to the windward watersheds of Maui, but water use continued to edge upwards, prompting another appeal for caution by Water Director Jeff Eng, The Maui News reported.

"We would like to remind all of our customers in the Central and South Maui areas that they remain on the 10 percent voluntary cutback restriction that was declared back on August 23, 2007," he said. "The department hopes that their conservation efforts will preclude having to impose mandatory water use restrictions."

A drought warning and mandatory cutback ordered for consumers on the Upcountry system was lifted in January — after a Kona storm in December and regular trade showers helped to restore water flows out of the East Maui watershed.

But the rainfall slowed after early February and the watershed is again showing stress from below-normal rain. Two days of drenching rains on Monday and Tuesday last week helped the surface water systems to recover, but the flows quickly dropped, according to water department reports.

The East Maui Irrigation Co.'s Wailoa Ditch, which provides water to the Upcountry system and to the Kula Agricultural Park, spiked to 154.5 million gallons a day Tuesday but was back down to 79.2 mgd on Thursday. It had been flowing at less than 40 mgd through the previous 10 days.

The West Wailua Iki rain gauge recorded more than 3 inches of rain over two days on Monday and Tuesday, and has had regular rains through the week. But the daily rainfall data have tended to be measured in the hundredths of an inch, with the spike of 1.34 inches Monday and 1.94 inches Tuesday.

The West Maui watershed showed even heavier flows, with the Puu Kukui rain gauge recording 1.54 inches Monday and 5.76 inches Tuesday.

But the Central Maui water system relies more on groundwater sources, with less than 2 mgd coming from the surface diversions from streams. While the water sources for Central Maui are more reliable, they are also capped at 24 mgd — 20 mgd from the Iao aquifer and 4 mgd from the Waihee aquifer.

With demand on the Central Maui system edging up toward the capacity of the sources, Eng said the department will be monitoring demand closely. The system serves the region from Wailuku to Paia to Kihei and Makena.

On the Upcountry system, Eng noted that the rains helped, but the department still needed to pump water from the Kamole Weir, drawing on the Wailoa Ditch, to provide water to the Lower Kula line and protect storage in the Piiholo Reservoir.

"For the week of March 13 to 19, production demand increased again throughout the county," he said. "Although we experienced a little rain in the East Maui watersheds that supply our Upcountry systems, the demand required us to continue pumping from Kamole up to the Lower Kula system."

Although there was a slight flow into the system through the week, the Upcountry reservoirs, which can hold 180 million gallons, were at just 58 percent of capacity with 105.9 million gallons stored Thursday.

The National Weather Service forecast continued moderate trade winds with a good chance of windward and mauka showers over the weekend, but drier conditions through the week.

For more Maui news, visit www.mauinews.com.