Posted on: Tuesday, October 21, 2003

Aquifer's level two feet lower than thought

By Christie Wilson
Advertiser Neighbor Island Editor

WAILUKU, Maui — New data from an ongoing study of the Waihe'e aquifer indicate the benchmark upon which water levels are based is two feet lower than previously believed.

That does not mean the aquifer is in immediate jeopardy, according to state Commission on Water Resource Management Deputy Director Ernest Lau. It does mean the commission will have to rethink a decision to place the Waihe'e aquifer under state control if the water table level were to drop to a trigger point established using data that now appear to be incorrect.

Lau said the aquifer's groundwater levels, pumping and chloride concentrations have remained stable over the past four years.

The previous benchmark for the water table level was 6 feet to 7.5 feet above sea level, but now that reference point has been revised downward by two feet. The water commission said in November that if the Waihe'e level dropped to 6 feet above sea level, the resource would be designated a state water resource management area and would no longer be under county control.

Automatic designation triggers for both the Waihe'e and neighboring '?ao aquifer were set in response to concerns that Maui's chief source of drinking water was being depleted. The '?ao trigger for overpumping was exceeded in June, placing the resource under state control.

Lau said yesterday that in light of new Waihe'e data showing a lower benchmark, the commission staff likely will recommend at an Oct. 29 meeting that action on possible designation be deferred until further study. The staff also will recommend that the state join the county and federal government to drill a deep monitoring well to get a more accurate picture of what is happening to the underground resource, he said.

The data were uncovered during a four-year, $1 million study by the U.S. Geological Survey. The county was required by the state commission to pay for the study.