On March 8, as torrential rains slammed down across the Hawaiian islands, operators of the Kaupakalua Reservoir in the Haiku region of Maui notified emergency management of an “imminent failure.”

The 138-year-old earthen dam, originally constructed to irrigate sugar cane farming, overflowed, forcing an evacuation order for people living downstream.

“The roar of the spillway was just incredible,” said Paul Thomas, who observed the dam overtop from his backyard on Peahi Road. Usually the water is well below the crest of the dam, but the scene before his eyes that day was concerning, he said.

Officials surveying the damage of the Kaupakalua overtopping found a bridge destroyed. Courtesy: DLNR

Kaupakalua, it turns out, was one of nine especially worrisome reservoirs across Hawaii that state dam safety officials put on an “expedited schedule” to fix last year. The owners later applied to remove the dam.

“We’re going to be proceeding our way through and start to set more defined schedules for these owners to comply with,” Edwin Matsuda, chief engineer in charge of dam safety for the Department of Land and Natural Resources, told Civil Beat in an interview on Monday.

Failure to comply can result in penalties and fines, the maximum of which is $25,000 a day, according to Hawaii’s dam safety law. Matsuda said if the owners of the nine dams don’t follow the schedule, which the state works with the owners to establish, then he’ll report them to the agency’s board.

The division he oversees has recently struggled to stay fully staffed despite years of government promises and new laws aimed at making dam safety improvements. Meanwhile, the fierce storms that increase the threat are only growing more frequent as experts warn climate change will worsen the situation.

After seven people were killed when the Ka Loko Reservoir gave way on Kauai’s North Shore just over 15 years ago, 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.

However, little has changed as many of the dams — most built in the 20th century and privately owned — were long neglected as relics of the once-thriving sugar plantation era and will take years and potentially millions of dollars to remove or upgrade.

Thousands of people living near the obsolete embankments may suffer the consequences with their fate largely left up to emergency plans, which are only required to address potential flooding, not prevention.

Hawaii has a special law — the Hawaii Dam and Reservoir Safety Act of 2007 — which allows DLNR to take enforcement actions for violations and in emergency situations. But the case of the Kaupakalua dam demonstrates how long enforcement actions can take, and how nature does not wait around for bureaucracy.

“Water is still going to fall from the sky,” said Shay Chan Hodges, chair of the Maui County Water Board, who, with her colleagues, has investigated the dams on the Valley Isle. “So where is that water going to go?”

State officials found debris at the site of the Kaupakalua Dam following the flooding last week. Courtesy: DLNR

Last week, state officials found the Kaupakalua reservoir backed up the stream a quarter mile mauka of the Peahi Road bridge, which the flooding destroyed. Pieces of the bridge’s guardrail and decking were found 300 yards downstream of the dam’s spillway.

The next day, DLNR revealed that the dam’s owner, East Maui Irrigation Co., which is co-owned and operated by Mahi Pono and Alexander & Baldwin, had been issued a notice of deficiency a year ago for failing to install a real-time water level gauge, and that Kaupakalua was scheduled for removal.

Kapalaalaea and the nearby Haiku reservoir, which also is owned by Mahi Pono, also received what DLNR’s dam and reservoir safety program refers to as a “notice of civil resource violation,” meaning the owner didn’t properly respond to the original deficiency notice.

Hawaii has 131 state-regulated dams. Kaupakaula was one of 120 that were labeled as having “high hazard potential,” meaning “failure or misoperation will probably cause loss of human life,” federal data updated in 2019 shows. Four others are listed as “significant,” which means failure could cause economic loss, environmental damage and other disruptions but likely not death.

State documents show that 68 of the dams had documented problems ranging from “abandoned conditions” to undersized spillways. Kaupakaula was one of nine that were so bad they received notices of deficiencies last year. At least 33 dams are required to be kept empty, meaning they are not actively used.

Other Dams With Notices Of Deficiencies

The dams are just one of several different infrastructure components that make Hawaii, the nation’s lone island state, especially vulnerable to natural disaster. What distinguishes the dams from most roads and bridges in the state, however, is that most are privately owned.


The hazard classification system also takes into consideration design, construction, operation and maintenance. But a report by the Association of State Dam Safety Officials found that 76% of the high-hazard potential dams in Hawaii were found to be in poor condition.

“That is very high in comparison to most states,” said Mark Ogden, a dam safety engineer and state outreach specialist with the association. “The fact that there are a significant number of dams that are rated as either poor or unsatisfactory is a concern.”

Nearly 70% are owned privately and have ties to sugar or pineapple farming. Top owners of Hawaii’s dams, according to the most recent data, included Hawaiian Commercial & Sugar Co. with 22 of the 23 dams it owns being listed as potentially high-hazard.

The data does not reflect the sale of former HC&S lands and dams to Mahi Pono, a joint venture between a California-based farming company and a Canadian investment manager. That group acquired more than 41,000 acres of former sugarcane lands in 2018 with plans to transform them for diversified agriculture by providing land and water resources for local farmers.

HC&S’s parent company, Alexander & Baldwin, is the second-largest state-regulated dam owner, with 15 of the 17 dams it owns labeled as having “high” hazard potential. That company also co-owns the East Maui Irrigation Co.

Hawaii Dam Inventory

Alexander & Baldwin owns and actively manages 17 dams — 16 on Kauai and one on Maui — for agricultural needs.  Company spokeswoman Lynn Kenton said most of the dams A&B owned on Maui were sold along with agricultural lands in 2018.

“We actively manage all 17 of our dams and work proactively before and during storm events to control water levels,” Kenton said.

In an emailed statement, Mahi Pono said it owns and manages 28 reservoirs and dams but only one-third of the reservoirs are actively being used for irrigation.

The company said it has engaged consultants to help determine the conditions of the reservoirs and dams and would either make required improvements “or move expeditiously to have them decommissioned” depending on what the assessment finds.

It also vowed to comply with all state requirements and said all requisite emergency preparedness and disaster prevention plans have been developed and approved by the appropriate state and county agencies.

“Our emergency response plan was fully executed during the overtopping of the Kaupakalua Reservoir and Dam last week,” it added. “We followed all protocols and worked closely with state and county teams to manage the incident.”

Matsuda of DLNR said Mahi Pono has been proactive thus far about keeping tabs on their acquired dams.

“From discussions that we’ve had with the owner and their engineer, they are progressing to run an initial take on all of their structures and trying to master-plan which ones they are going to keep and how they’re going to alter these situations,” he said.

Ties To Sugar Farming

A 2019 infrastructure report card from the American Society of Civil Engineers gave Hawaii’s dams a “D,” saying their old age poses a risk to communities that have developed around them.

“The majority of these dams were constructed as part of irrigation systems during the rise of the sugar cane industry and many are nearly 100 years old,” it says. The average age of Hawaii’s dams, according to latest data, is 89.

But with the sugar industry’s demise in 2016 when HC&S closed its last mill on Maui, “many of the dams that generated agriculture revenue to fund maintenance operations have fallen into a state of disrepair,” the report says.

The Ka Loko Reservoir on Kauai was also built to support sugar farming for the Kilauea Sugar Plantation back in 1890, according to an independent investigation that took place after its breach in 2006.

While that reservoir and many others converted uses to support small farmers or even municipal water systems, the report also noted that “the economic engine of the sugarcane industry no longer provides the resources to maintain these water systems.”

This archived photo shows the Ka Loko Reservoir breach from 2006, when seven people died. Polihale/Wikipedia

Matsuda agrees. “Back in the sugar plantation days, they had a lot of staff to maintain these structures,” he said.

Now, the structures have far fewer people on site managing them, and his division tries to train dam owners on the required safety steps at least every other year.

Hodges said the 2019 investigation by the Maui County Board of Water Supply found that most of East Maui Irrigation’s eight reservoirs and 48 others on the island have not been used for at least five years.

The upgrades required to return them to service range between $50 and $100 million, the investigation found. It will be costly and challenging, but if fixed, they could store water for about 16 days, Hodges added.

“We should be investing in reservoirs,” she said. “We should be investing in whatever it takes to conserve the water.”

When dam owners don’t have revenue streams, it can be challenging for regulators to get them to upgrade or remove deficient dams, Ogden of the dam safety association said. State authorities have limited power when it comes to private property rights.

“It’s a problem that a lot of states grapple with,” he said. Unlike bridges or roads, which are mostly publicly owned, Ogden said many dams are privately owned — 63% nationally and 69% in Hawaii, according to the National Inventory of Dams.

Yet, Kaupakalua makes evident how long the process can take. DLNR sent a notice of deficiency to its owner in February 2020, and the owner submitted a permit for removal in October.

At least 11 other dams are in various stages of the removal process while at least 17 others are up for repair, improvement or rehabilitation, a state report of the program’s fiscal year 2020 activities said.

In that same report, DLNR notes that many of the dams “are over 80 years old, and almost all were constructed before the development of any modern safety standards.”

The state agency adds that it’s working with owners to “establish a reasonable improvement schedule” to make the necessary fixes.

Matsuda noted fixing dams is not an easy challenge, often requiring money, studies and permits that could take years.

“A lot of times these deficiencies are not small things to fix,” he said. “It’s not like replacing a doorknob or a faucet or something.”

Climate Change Factor

Neither the state nor the federal government has any control over the weather, however.

Maui resident Melani Chang’s home after last week’s flood. She said the water kept rising. 

National Weather Service Warning Coordination Meteorologist John Bravender said the rain last week was extreme, but likely part of a broader trend.

“It’s not possible to tie any one heavy-rain event or weather event to climate change directly, but we are seeing across the board an increase in the frequency of extreme events like this,” said Bravender, a 20-year veteran of the NWS.

Right now, the main protection for those who live near potentially hazardous dams are Emergency Action Plans, essentially manuals for dam operators to follow in case of an emergency.

Hawaii state law requires all high hazard dams to have them, and all but one of the state-regulated dams — a federally operated dam — have EAPs on file.

“Emergency action plans can save lives,” Ogden said.

DLNR emphasized the role of the EAP in the swift and alert evacuation of Haiku residents when the Kaupakalua dam overtopped March 8.

But those emergency action plans are for exactly that — emergencies. They aren’t designed for prevention.

Meanwhile, the people who live near hazardous dams in poor condition must remain in constant vigilance, especially as heavy rains continue.

Living Near Dams

The Hawaii Emergency Management Agency recommends that residents sign up for emergency alerts, and maintain emergency kits.

Lucienne de Naie, secretary of Haiku-based conservation group Malama Hamakua, said she has been hearing from locals concerned about the management of the water system.

“People want to have a real discussion about how we manage the dams, the ditches, the streams, in light of the fact that our storms might be changing in intensity,” she said.

The Kaupakalua Dam is set to be removed. If weather permits, the construction could begin as early as this summer, DLNR engineer Edwin Matsuda said. Courtesy: DLNR

Suzanne Case, the DLNR chair, said dam safety officials will continue to work with private and public owners to bring them into compliance with safety regulations.

Kaupakalua’s overtopping “certainly indicates the removal is necessary to protect people and property,” she said last week in a news release.

“This is really an example of climate change in the present day,” she added. “We have a flood emergency because of the heavy rain bomb.  And we’re seeing these more and more across the island chain – more frequent and more extreme events.”

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