Central, South Maui water use increasing
WAILUKU — The trade wind showers that kept Maui watersheds flowing early in February have dropped off dramatically — providing clear skies and cool mornings but driving up water use.
Maui County Water Director Jeff Eng said Friday that the lack of rain over the past two weeks has led to an increase in water use that he said is clearly from residents watering their lawns and landscaping.
From Feb. 14 to 21, water use jumped 14 percent, with most of the increase occurring on the Central Maui system that supplies consumers in Central and South Maui.
“It is obvious that this increase is attributed to outdoor water usage,” Eng sad. “We ask our customers to closely monitor their irrigation practices and to not over water their yards.”
Demand on the Central/South Maui system remained well below the peak of more than 28 million gallons a day recorded last summer, but it nearly matched the average demand in February 2007, when Maui County was heading into a drought situation that prompted the water department to order restrictions on water use.
National Weather Service rainfall data for February showed a sharp drop in moisture across the county, as the trade winds backed off and a flow of trade showers disappeared.
Over the two weeks between Feb. 10 and Saturday, the West Wailua Iki rain gauge in the East Maui watershed recorded just 1.02 inches of rain while Puu Kukui on the West Maui summit received 0.61 inches. Over the first 10 days of February, Puu Kukui had received 30.63 inches and West Wailua Iki recorded 23.33 inches.
Over the past two weeks, Maui’s primary farming area, Kula, received just 0.17 inches — forcing Upcountry farmers to rely more on irrigation to keep their crops healthy. But the demand over the past two weeks remained well below the average 7.19 mgd recorded in February 2007.
In contrast to Upcountry, demand is up 2.78 mgd in Central/South Maui — where most of the county water goes to homes and businesses — to 23.06 mgd from a low average of 20.28 mgd during the first week of February.
While Upcountry consumers are still keeping their use down, the Upcountry system is showing the effects of the slowdown in rainfall in a loss of supply. Water flow into the Upcountry system — which relies primarily on stream sources — has fallen off sharply over the past week. Reservoirs that were nearly full at 175 million gallons on Feb. 1 were down to 143.5 million gallons on Friday. Another indicator of the condition of the watershed, flows in the Wailoa Ditch, were down from 195 mgd on Feb. 1 to 74.8 mgd on Friday. The ditch, with a capacity of up to 200 mgd, provides drinking water for Upcountry as well as irrigation water to the Kula Agricultural Park and Hawaiian Commercial & Sugar Co. fields.
The National Weather Service forecast indicates there may be relief from the ongoing dry spell by Monday, but it will be fast moving and may not amount to much. A cold front is on track to bring clouds and showers to Kauai and Oahu today, and move over Maui County by late tonight or early Monday. But it will be weakening and there was uncertainty over how much moisture it will be carrying by the time it gets to Maui and the Big Island.
A weak high pressure system behind the front should move in by Tuesday but bring only light trade winds and a shot of cool mid-latitude air, similar to what was passing over the islands during the previous week. A stronger high pressure system may build up the trades on Thursday, the forecast said.
For surfers, the forecast indicates the week will offer plenty of rides with both light winds and new swells arriving on north and south shores. An unseasonable south swell is expected to arrive today, while a northwest swell from a storm just below the Aleutians may be arriving by late today. The weather service said the northwest swell may hit warning levels of 15 to 20 feet Monday night.
