The Wailua Reservoir Dam was built a century ago to provide water for a thriving sugar industry on Kauai. With the sugar plantations long gone and agriculture on the decline, the reservoir and dam — now run by the state — no longer serve their original purpose.
Now the state is proposing to drain the 200-acre reservoir and put a wrecking ball to the dam in a move to eliminate a growing financial burden and potential safety hazards to the residents below.
The state has issued a notice of intent to write an environmental impact statement laying out the alternatives for the future of the dam, reservoir and diversion from the North Fork Wailua River, and the public has until May 8 to comment on the effort.
The project wasn’t exactly embraced at a recent virtual scoping meeting held by the project’s environmental consultant.
Among other things, officials were told that getting rid of a functioning reservoir will limit future agricultural opportunities and is contrary to the state’s goal of being self-sufficient in food production.
“The members I’ve talked to unanimously oppose this effort,” said Mark Perriello, president and CEO of the Kauai Chamber of Commerce. “As a state, we have this really ambitious goal about food sustainability, and you’re taking away one of the tools that will enable that to happen.”
Wailua Reservoir Dam is an earthen structure 40 feet high and more than 1,000 feet long. The storage capacity of the reservoir is 274 million gallons, but the normal pool is approximately 111 million gallons.
The source of the Wailua Reservoir is natural stream flow and water diverted from the North Fork Wailua River. But the reservoir no longer provides irrigation water to a deteriorating and dilapidated series of ditches, laterals and tunnels that once fed the fields of sugar cane as far away as 20 miles to the northeast.
The existing system is no longer viable without a substantial amount of maintenance and rehabilitation, according to the project’s EIS preparation notice.
While the reservoir is no longer used by large-scale agriculture, it does serve as a public fishing area and is stocked with bluegill and bass. The reservoir, however, is not considered highly used.
For nearly two decades the reservoir was managed by the East Kauai Water Users Cooperative, operating under a revocable permit from the state Department of Land and Natural Resources. At the end of 2019, the cooperative voted against continuing the revocable permit, leaving DLNR to take over management and operation of the reservoir.
However, DLNR says it lacks the resources for continued operation of the dam, reservoir and irrigation system.
What’s more, the dam is classified as having high hazard potential, indicating that failure of the dam and high rainfall events could threaten the population downstream.
There are 126 private and public dams statewide. Of those, 118 are classified as high or significant hazard potential structures.
Officials have acknowledged that the Wailua Dam is in decent shape, having undergone a rehabilitation project in 2012. The high- hazard classification merely refers to what could happen if the dam were to breach.
“So there is no imminent threat of failure,” said Ian Hirokawa, DLNR special projects manager.
Hirokawa said DLNR has searched unsuccessfully for a new dam operator since 2019.
The best prospect, he said, is probably the state Department of Agriculture, which launched a study in 2022 to determine the number of system users, water demand and extent and condition of irrigation facilities. The study has yet to be completed.
“Ideally, if we could find another operator, that would be great,” he said. But the Agriculture Department, like DLNR, likely would need to search for extra funds in order to staff and operate the facility.
Hirokawa said DLNR spends roughly $150,000 a year to operate and maintain the dam and reservoir, and that annual expense only promises to grow in the future as it degrades over time.
Meanwhile, the cost to drain the reservoir and remove the dam is estimated at $2 million or more and would require 14 possible federal, state and county permits.
“We don’t really have the funds to do either,” he said. “To either maintain it in an optimal operational state or to decommission it, we would have to seek funding.”
The only entity that currently relies on water from the reservoir for its irrigation is Kauai’s Hindu Monastery, located below the dam.
A spokesman for the monastery said he understands maintaining a reservoir for a single user isn’t viable. But he said the state’s mandate to improve food self- sufficiency and possibly losing an irrigation source shows a disconnect.
Ruta Jordans, a resident of Wailua Homesteads, agreed.
“If we want more agriculture land and more farms, they will need reliable sources of water. The climate is changing, and it appears that there are chances that there will be more times of prolonged drought, such as Maui has already experienced,” Jordans said.
“A system such as the Wailua Reservoir and Wailua Ditch would be invaluable for more farms in the future and in case of drought. Renovating it would be much less expensive than trying to build it from scratch once we actually are able to be more self-sustaining with agriculture,” she said.
To comment on the proposal, write to the state’s consultant, Gannett Fleming, at tpearl@gfnet.com. The project’s website is at wailuareservoir.com.