Kaupakalua Dam in Process of Being Decommissioned; Slated for Removal this Summer

The 136-year-old earthen Kaupakalua Dam which overflowed on Monday, had been cited for deficiencies last year and owners had applied for permits to remove the structure, the state Department of Land and Natural Resources confirms.

The Kaupakalua Dam in Haʻikū overtopped with water from its reservoir during historic rains yesterday, forcing evacuations downstream.

“On February 18^th of last year, the dam’s owner, East Maui Irrigation Company (EMI) and Mahi Pono Holdings Inc., were sent a Notice of Deficiency letter setting a compliance schedule to remediate the structure’s deficiencies,” according to information released by state officials today.

Mahi Pono confirms that the structure is in the process of being decommissioned.

“Prior to yesterday’s rain storm, the reservoir was empty. The reservoir is not being used to collect water for irrigation purposes and is dry under normal conditions. A valve is kept open as a pass-thru mechanism to allow water that enters the reservoir during typical rain events to quickly exit and continue to flow downstream,” the company said in a statement provided to Maui Now.

“The owner has been working with the State in complying with this NOD, and in October 2020 submitted a dam safety permit application to remove this structure, which is targeted for construction this summer,” the update noted.

Less than two weeks ago, a follow up notice was issued by DLNR on Feb. 24, 2021, indicating that there was a “failure to comply with the remediation and monitoring actions and deadlines of the prior notice.”

The notice notes specifically the failure to install a real-time reservoir water level gauge with the readings accessible on the internet by May 30, 2020, as required by state statutes. According to DLNR, a water level gauge that was previously installed at the Kaupakalua Dam was stolen in 2018.

“The owner is working with the State to have this gauge replaced in addition to installing gauges at three other reservoirs on Maui (Kapalaʻalaea, Haʻikū, and Reservoir 24),” according to the DLNR update.

Mahi Pono reports that regarding the Hawaii Dam & Reservoir Safety Program Report for FY 2020: In 2017, EMI received a notice of deficiency for Kaupakalua Reservoir on three items – (1) Topography, (2) Hydraulics, and (3) Real-time gauge. “The first two items have been resolved. The third item – related to a non-structural gauge installation in Kaupakalua Reservoir – is in the process of being resolved,” the company reports.

Of the 130 State-regulated dams in Hawai‘i, 126 are classified as high or significant hazard potential structures due to proximity to people and structures downstream.

All of the regulated dams, except one, now have Emergency Action Plans (EAPs) on file with DLNR, and all Emergency Action Plans have been migrated and updated on the DLNR’s “Easy EAP” tool.  

*Find out if you are in a dam zone.

‘The Emergency Action Plan for Kaupakalua is what resulted in yesterday’s immediate public safety alerts and the evacuation of people downstream of the dam,” according to DLNR.

DLNR Chair Suzanne Case said, “Our Dam and Reservoir Safety Program works continuously with private and public owners of dams and reservoirs to bring them into compliance with all required safety regulations. Yesterday’s overtopping of water over this dam certainly indicates the removal is necessary to protect people and property. We will continue to work with the dam owners around the state to ensure the optimum level of safety and awareness possible.” 

Mahi Pono reports that after commissioning a review and study of the existing reservoir and dam, it was determined that removing the dam and decommissioning the reservoir was the best option. “Last year, EMI submitted a permit application for the dam’s removal to the State Department of Land and Natural Resources and the U.S. Army Corps of Engineers. All costs associated with the removal is the responsibility of EMI,” according to the company.

As of October 2020, the permit application is still pending.

“At this time, we are not aware any property damage that occurred due to the over-topping.  However, this does not diminish the damage caused in the surrounding community located mauka of the reservoir by the overwhelming and unprecedented rainfall here on Maui,” said Shan Tsutsui, chief operating officer, Mahi Pono.

At least a half dozen homes were heavily damaged or destroyed yesterday, according to Mayor Michael Victorino who described the flash flood event as “unprecedented flooding.” He urged the public to remain vigilant and stay safe as damage assessments continue today.