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District stewards want to see the Lahaina Watershed Flood Control Project completed

By Staff | Aug 22, 2019

The Lahaina Watershed Flood Control Project was designed to span from Lahainaluna Road to a drainage outlet at Waianukole, two-thirds-of-a-mile south of Puamana Park, through about 10,000 feet of grass-lined channel, four sediment basins, one debris basin on Kaua‘ula Stream and one outlet basin near Lahainaluna Road.

LAHAINA – Flooding in Lahaina is on the average a once-in-every-five-year occurrence, with the resulting annual damages totaling an estimated $700,000. Since 1879, there have been 26 major floods.

The heaviest downpour was experienced in the Kahoma Watershed in 1960, with 21.7 inches of torrential rains flooding 30 businesses and homes. Front Street and Honoapiilani Highway were overtopped. In today’s terms, the financial hit was between five and ten million dollars.

According to the Soil and Water Conservation District website, the next 100-year storm could be devastating. It is projected that damages would potentially impact 197 residences, 35 condominiums, 157 businesses, two parks, two schools and the main roads.

West Maui and its lawmakers should pay attention – the Lahaina Watershed Flood Control Project was never completed.

It’s had an on-again, off-again history since it was first proposed to the USDA Natural Resources Conservation Service by the West Maui Soil and Water Conservation District (WMSWCD) in 1981.

Luckily, we have a group of volunteer WMSWCD stewards to protect us, including James J. Nobriga, chairman; Daniel Pomaika’i Kaniaupio-Crozier, vice chair; Kimo Falconer, treasurer; Ian Swezey, secretary; Kainoa Casco, director; and associate directors Dave Minami, Wes Nohara and Daniel Ornellas.

They are charged to see this vital, two-mile flood diversion system completed, as it channels flood waters southwesterly from Lahainaluna Road to Waianukole, two-thirds-of-a-mile south of Puamana Park, through about 10,000 feet of grass-lined channel, four sediment basins, one debris basin on Kaua’ula Stream and one outlet basin near Lahainaluna Road.

Over the years, however, its course has been anything but straight, wavering its way past different channelizations and environment assessments. The current design was approved as pictured when the project broke ground late 2009.

“The Lahaina Watershed Flood Control Project included five phases: 1, 2B, 3A, 3B, and 4/5. Phase 1, a Diversion Channel, was installed in 2011. Phase 2B, also a Diversion Channel, was installed in 2013. Phase 3A, Hokiokio Place, was installed in 2014. The design of Phase 3B, a Debris Basin, was completed in 2014. Phase 4/5 was not completed,” advised Susan Kubo, Natural Resources Conservation Services spokesperson.

The costs of the early stages were shared by the federal government and the county.

Unfortunately, construction came to a grinding halt when funding was pulled. The debris basin at the intersection of Kaua’ula Stream was designed but never built along with Phase 4/5, and it’s been sitting on the shelf ever since.

“In the meantime,” Kubo added, “times have changed; environmentally, things can never stand still.”

“The Commission on Water Resource Management (CWRM) says if you guys build this sediment basin, it’s going to disrupt the water flowing from mauka to makai,” Falconer worried.

“We’re trying to get this thing built. In the meantime, we’ve had floods in town; we’ve had homes damaged. All of that stuff happens, because we don’t have a system in place to move the waters where it can properly drain. Then on top of that, they built the Lahaina Bypass (south). Now the bypass is exacerbating the problem.

“Before you had the sheet flow going through cane fields. We had rain diversions circulating it into 100-year storm small streambeds and what not; but now it’s going to be coming out of all these culverts (under the bypass). Just big water coming out. When it happens again, we’re not going to have control,” he reasoned.

“Potentially, we have to change the design (of the project),” Falconer continued, “which would trigger another EIS, another EA, another million dollars here. Anytime you change something like the bank of a big sediment basin, it’s gonna trigger further studies. We’ve been down this road at least twice if not three times already in the last 35 years.”

According to Kubo, dollars are currently available.

“In 2017, after several years of no appropriations, NRCS received funding in the Watershed and Flood Prevention Operation Program. As a result, NRCS is reviewing watershed projects that have remaining measures for implementation, to see if they can be moved forward towards design and construction. Because in some cases environmental compliance documents and designs for projects were done many years ago, it is necessary to reaffirm the feasibility and viability of the projects,” she said.

Nobriga is positive .

“The district (WMSWCD) and its co-sponsors are diligently working on trying to obtain the required funding to complete this project. We’re doing it conjunction with the NRCS and County of Maui.”