Koloa, Po’ipu residents fearful of failure of Waita Reservoir

By governmental leaders’ own assessments, a breach of the Waita Reservoir above Koloa would result in “more than a few” lives lost, and excessive damage to homes, businesses, agriculture, utilities and public roads.

After last month’s torrential rains that caused flooding in Koloa and elsewhere, residents of Koloa, Po’ipu and Kukui’ula are worried about what a breach of Waita and surrounding reservoirs could mean, and have put together a public meeting Monday at 6:30 p.m. at the Koloa Neighborhood Center.

While the Ka Loko Reservoir breach caused millions of gallons of water to flow seaward, taking out part of Kuhio Highway in Kilauea, sweeping away at least two homes and killing at least seven people, a Waita breach would send billions of gallons of water toward Koloa, Kukui’ula and Po’ipu, over ground that is much different than that in Kilauea, according to organizers of the Koloa meeting.

Think pouring water on a garage floor, meeting organizers including Teddy Blake said.

The Koloa soil is loose, covering pahoehoe lava indicative of the volcanic origins of the oldest island in the chain, he said. While the softer, deeper Kilauea soil allowed the flowing water to form a trench, the same situation would not occur at Koloa.

The concerns have caught the eye of important state officials, and Gov. Linda Lingle, state Adjutant General Maj. Gen. Robert Lee, director of state Civil Defense, and representatives of the U.S. Army Corps of Engineers, Kaua’i Civil Defense Agency, state Department of Land and Natural Resources, and U.S.

Geological Survey have confirmed their attendance at the Monday meeting, said Blake, a Koloa resident.

Representatives of Grove Farm, the Waita Reservoir owner, and Alexander & Baldwin, another major South Shore landowner, will also be in attendance, Blake said.

The purpose of this meeting is to obtain information about how much water is contained in reservoirs above and west of Koloa, and actions being taken to prevent a Ka-Loko-type disaster, that include but are not limited to reservoir water levels, dam integrity, and watercourse maintenance.

At maximum capacity (22 feet deep), 2.5 billion-plus gallons of water are contained in Grove Farm’s 420-plus-acre Waita Reservoir, built in 1906.

A&B’s six-reservoir capacity, west of Koloa, is 568 million gallons. These reservoirs are situated above and or to the west of Koloa, Kukui’ula and Po’ipu, and receive surface water runoff from the upper Koloa plain.

Koloa Town, Po’ipu and Kukui’ula are located on the downside of these reservoirs.

A major dam or dams failure would wreak havoc on everything in the water’s path, causing flood damage that could well exceed the damage caused by hurricanes ‘Iwa and Tniki, meeting planners said.

The Koloa plain, unlike Kilauea with its deep topsoil, consists of shallow soil atop pahoehoe. The water from Ka Loko was able to dig a deep trench, which contained it while it was en route to the sea.

Koloa is different.

There is nothing to contain or to direct the flow.

The water just spreads out and runs downhill to Kukui’ula and Po’ipu, meeting planners said.

The meeting is open to the public.

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