WAILUKU -- Statistics from the U.S. Geological Survey confirm that the North Waihee expansion by the Department of Water Supply has reduced the strain on Iao aquifer.
Water levels in Iao wells have been dropping since 1990, and the saltwater intrusion level has risen. That caused the state Commission on Water Resource Management to initiate hearings that could lead to ``designation,'' or state control of the aquifer.
But Bill Meyer, Geological Survey district chief, wrote Water Supply Director David Craddick Friday that the drop in water levels has ended, except at North Waihee and the observation well closest to North Waihee.
The North Waihee well went into service in midsummer, and its level is the lowest ever measured.
That is according to plan. North Waihee is in a different aquifer (though there is some ``leakage'' of groundwater across the Waihee Stream.)
The commission has said it will designate Iao if the average take exceeds 20 million gallons a day (yearly rolling average, calculated each month).
A year ago, pumpage from Iao was nearly 24 mgd. This past September it was 20.34 mgd.
While still over the 20 mgd target, that was low enough to keep the 12-month average below 20.
The addition of North Waihee water, a wetter season and conservation by users have contributed to the turnaround.
``A lot of the difference is due to conservation,'' said Craddick.
Because the 12-month average draw includes wet winter months, when the daily take typically runs around 17-18 mgd (sometimes less), and the dry summer, the average continues to fall even though summer pumping remains above 20 mgd.
In August the rolling average was 19.6 mgd. In September it was 19.4 mgd.
The measure of water quality, which is salt content, has not shown much movement compared with a year ago, Meyer wrote.
There is no mandated level of chloride (salt) for drinking water, but Meyer uses a figure of 250 milligrams per liter or less as ``good'' water.
Even the worst wells in Iao are well below that.
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Psy 412 Miami University. Last revised: . This document has been accessed times since July 15, 1997. Comments & Questions to R. Sherman .