When Kauai’s Kalihiwai Reservoir was built in 1920, its value was tied to sugar cane, the economic engine that propelled Hawaii into statehood before competition from cheap foreign labor forced the industry to flee the state.

The reservoir, situated at the center of a neighborhood of luxury homes in one of the rainiest places on earth, has been through a lot since then.

After a century of use, the earthen dam has produced downstream leaks flagged by state regulators as potential safety hazards. The spillway, where surplus water can freely flow if the reservoir overtops, is too small. And the embankment slopes are too steep, a potential stability problem for the walls that hold the water in.

Erosion and the passage of time contributed to these deficiencies, first identified by state dam safety inspectors in 2006. Another factor is that dam safety regulations simply didn’t exist when the reservoir was constructed.

Today the aging water system is at a crossroads. A May 1 deadline looms by which the state requires its private owners — a neighborhood association and a pair of legacy agricultural plantations that no longer rely on the reservoir — to submit a permit to either upgrade or remove the reservoir.

With little economic incentive to fund a multimillion-dollar fix, the owners are preparing to decommission the reservoir — a far cheaper alternative to rehabilitation.

None of the reservoir owners would disclose the estimated dollar amount to restore the reservoir. But Andy Lynch, a Denver-based engineer at Gannett Fleming, the company hired by the dam owners to study the steps and costs associated with fixing or removing the reservoir, confirmed that decommissioning it is the most cost-effective option.

“Particularly in Hawaii, where the financial benefit of a lot of these dams and reservoirs no longer exists, it just doesn’t make sense for small private owners,” Lynch said. “If the dam isn’t making money, it’s hard to justify investing millions of dollars in it.”

In Hawaii, dam ownership is diverse, ranging from major land developers, such as Alexander & Baldwin, to county boards of water supply to individual people.

But the consequences of losing a reservoir often spill beyond the reservoir’s ownership. If Kalihiwai Reservoir fades out of existence, it could threaten the growth of a nearby community agricultural enterprise. Rare native birds would lose a habitat.

While removing the reservoir can be viewed as a positive move for the health of the river since it would restore the natural water flow, it would destroy the wetland ecosystem established 102 years ago.

Maggie Lea, who lives near the reservoir in Kalihiwai Ridge and operates a website devoted to its history and value as a natural resource, said the decision to get rid of the dam is short-sighted.

“It’s just overwhelming to see how something so valuable is going to be lost,” she said. “It’s one of these things that has all these potentials — community recreation, climate adaptation, agriculture, wetland habitat, fire suppression. And we’re just going to blow it up.”

Risky To Keep, Risky To Remove

Hawaii has 127 state-regulated dams, most of them built in the 20th century and privately owned. Crippled by divestment, many of these antiquated water systems need attention.

Kalihiwai Reservoir is one of the state’s 120 high-hazard dams, meaning there’s a high potential for the loss of life as a result of a dam failure. 

After seven people were killed when the Ka Loko Reservoir gave way on Kauai’s North Shore in 2006, Hawaii became the poster child in a nationwide campaign to boost dam safety, with an increase in funding and staffing for the state’s program.

“I wish they would find a way to save it but that’s not up to me.” — Edwin Matsuda, chief engineer of dam safety

Since then, 23 dams have been removed from the Department of Land and Natural Resources’ jurisdiction, meaning they’ve either been decommissioned or downsized significantly so that they no longer require state oversight. There are currently permits out to remove two more: Omao Reservoir on Kauai’s south shore and Ukumehame Reservoirs in central Maui.

Soon, Kalihiwai Reservoir could make it three.

No longer a critical water source for agriculture, Kalihiwai Reservoir remains a recreational resource for fishing and boating. It has historical significance. And it adds value to about a half-dozen homes with a water’s edge view. 

The reservoir is a federally recognized wetland habitat for at least three imperiled species of Hawaiian waterbirds: nene, the Hawaiian coot and the Hawaiian moorhen. It’s a method of flood control. And it provides fresh water storage that could be useful during times of drought or for fire suppression.

If its owners somehow stave off removal, the reservoir may also play a key future role in Kilauea’s revitalization as a hub for agriculture.

Yoshi L’Hote, director at the nonprofit community agricultural center Aina Hookupu O Kilauea, said he has been counting on water from Kalihiwai Reservoir to continue the farm program’s growth.

The 75-acre farm currently relies on county drinking water for irrigation. If the reservoir no longer exists, L’Hote said the organization will likely need to drill three wells into the aquifer.

“If 10 years from now we quadruple our agriculture activity on the North Shore, then we’ll be going, ‘Oh, shucks, we shouldn’t have done that,’” he said.

According to L’Hote, the reservoir’s role in capturing and storing fresh water could be beneficial not only to the farm, but to the whole island.

“If we lose it, then we’re going to have to drill wells into the same aquifer and if it doesn’t rain for three years that aquifer is really going to be impacted to where we might compromise it,” he said. “That’s kind of crazy when we have all this water storage and removing it is going to send that water straight into the ocean.”

Not every dam needs to be saved, said Edwin Matsuda, chief engineer in charge of dam safety for DLNR. But he said the department is concerned that some water systems that play an important role in managing fresh water, recharging the aquifer and mitigating flood risk could be removed due to a lack of appetite among owners to fund repairs from which they no longer financially benefit.

“I think Kalihiwai is one of the more beautiful structures that we have in the state,” Matsuda said. “But it can also be dangerous. I wish that they would find a way to save it but that’s not up to me nor is it my place.”

In 102 years, the reservoir overtopped twice, most recently in 2018 when a record-setting storm dumped 49.7 inches of rain on Kauai’s north shore in 24 hours.

During the storm, the former manager of the water system worked to plug low spots on the embankment with dirt, an effort that Matsuda said probably helped save the dam from more severe damage or even failure.

About two inches of water spilled out from the reservoir, joining a deluge that blew out a culvert and washed away a large portion of Kahiliholo Road, the main artery of the Kalihiwai Ridge neighborhood. The damage caused a nearly year-long road closure that cost about $1.5 million to fix.

Matsuda said it’s impossible to know whether the water that spilled out of the reservoir, when combined with all the other flood water, played a significant role in causing the damage. 

State rules require high-hazard dams to be built to withstand what’s called probable maximum precipitation, or the maximum depth of precipitation at a location for a given duration that is meteorologically possible. For Kalihiwai Reservoir, this coincidentally works out to about 49 or 50 inches of rain in a 24-hour period, according to Matsuda, or about the same amount of rainfall Kauai’s north shore received during the historic 2018 flood.

‘It’s An Environmental Crime To Let This Thing Go’

Kalihiwai Ridge Community Association President Elizabeth Letcher said in an email that the cost of upgrading the dam is beyond the financial capacity of the neighborhood association. And since she said some of the other owners preferred dam removal, the state was notified in late January of the owners’ joint intent to remove it.

Letcher said she’s heartbroken over the impending loss of a water system with value to the broader north shore community, wildlife, agriculture and climate change resilience. But the neighborhood association simply can’t afford to bear the cost of remediation without help.

Another reservoir owner is Common Ground, a food business development, agriculture and events space on an 83-acre former guava plantation.

Chief Operating Officer Jennifer Luck said in an email that the three owners jointly decided to decommission the reservoir after years of consideration because the cost of remediation and ongoing maintenance was expected to be significantly higher than originally anticipated.

Common Ground uses a minimal amount of reservoir water to feed its agriculture projects, Luck said, but the nonprofit has access to an alternative water source for current and future production.

The owners of Wai Koa Plantation, a 528-acre agricultural property that’s for sale for $22.5 million, did not respond to requests for comment.

If it’s needed, Luck said Wai Koa, the third partner in the reservoir’s ownership, has access to an alternative water source for irrigation, as well.

In 2019, FEMA started awarding federal grants for state agencies to facilitate the rehabilitation of high-hazard dams. The DLNR was awarded $419,546 from the program in 2020 but that money has not been spent yet, according to Matsuda.

The funds went to the Honolulu Board of Water Supply but upon reviewing the conditions of the grant the board decided to fund its dam rehabilitation project on its own, Matsuda said.

DLNR is in the process of working with FEMA to amend the terms of the grant so it can be used for risk assessments, which is a method of prioritizing dam deficiencies based on probable risk, Matsuda said. The agency has not applied for more dam rehabilitation funds from FEMA since receiving the 2020 award.

“When we do inspections it’s pretty black and white — there’s either a deficiency or not, it either has the required slope or not. It’s pretty prescriptive,” he explained. “So for Kalihiwai, their spillway is undersized. Well, how likely is it to fail? If there were to be a storm that came through, how much confidence do you have that they can anticipate and manage that?”

The dam safety program has conducted about eight of these risk assessments so far statewide, Matsuda said.

Makaala Kaaumoana, a Kalihiwai Ridge resident and advocate for managing watersheds as a natural, cultural and economic resource, said she’s tried unsuccessfully to compel DLNR to apply for more funds from the FEMA Rehabilitation of High Hazard Potential Dams Grant to help ensure a future for Kalihiwai Reservoir.

She’s also tried to stir up philanthropic interest in funding the required dam repairs, she said.

“To me it’s an environmental crime to let this thing go,” Kaaumoana said. “But it doesn’t have to go. Millions of dollars is chump change to some of the people who live up here.”