MATTAWA, Wash. — Officials investigating leaking at the Priest Rapids Dam on the Columbia River say the source is likely the layers between large sections of concrete.

The Grant County Public Utility District, which operates the dam, says the hydroelectric dam in southeast Washington continues to operate as usual and there’s no threat to people or property.

Northwest News Network says the dam, which sits directly upstream from the Hanford cleanup site, is stable and no movement has been detected. But it’s leaking up to four gallons of water a minute at four lift joints, the area between concrete blocks poured at different times.

The utility declared a “non-failure emergency” in late March after inspection drilling found leaking in the spillway monoliths. Dam operators lowered the reservoir behind the dam to lessen pressure.

The utility says that inspection drilling has been completed on about half of the spillway and will continue into May.

Officials say they’ll decide what remedies may be needed once the investigation is completed.

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