A shiny new aluminum channel will soon replace the rotting and aging redwood of the Waikamoi Flume, a piece of Maui's history built in a forest on the ridges and valleys above Haiku more than 70 years ago.
An $11.2 million replacement project is ongoing on the 1.1-mile-long flume, one of several water collection systems that feed into the Olinda Treatment Plant that supplies water to customers in Kula, Keokea and Ulupalakua.
The project is expected to be completed around December 2014. Due to the degradation of the flume through the years, an estimated 40 percent of water during peak flows is being lost through cracks and holes along the timber box. The aging system also has posed hazards for maintenance personnel who walk the flume, water department reports indicated.
Parts of the more than 70-year-old wooden Waikamoi Flume have already been demolished to make way for a new aluminum channel. To keep the flume functional when the repair work is ongoing, crews have installed a temporary water pipe over an existing water pipe at the flume site. The repairs are expected to be completed by December 2014.
Maui County photo
An estimated 40 percent of water during peak flows currently gets lost from the Waikamoi Flume as it is plagued with cracks and holes.
Maui County photo
Aluminum parts made to replace the aging wooden Waikamoi Flume are seen here in a warehouse in Washington State. The parts were flown to Maui.
Maui County photo
While more water will reach the Olinda Treatment Plant when the repairs are completed, exactly how much is not known, said Dave Taylor, county director of water. He added that there are no gauges on the flume and no historical data to determine how much water goes through it.
Still, the repairs will help the county issue more water meters Upcountry and will keep Upcountry reservoirs fuller during drought periods, Taylor said during a department presentation on the flume to a Maui County Council committee last week.
East Maui Irrigation Co. and Maui County currently manage the flume system that spans three stream systems, Haipuaena, Puohokamoa and Waikamoi. The system has 14 major gulch crossings, ranging from 8 feet high to 31 feet high. The current flume supports are wood but will be replaced by aluminum as well.
Tom Ochwat, the county staff engineer in charge of the design and the construction of the project, said the aluminum parts were put together at a fabricator's warehouse facility in Washington state and were shipped to Maui.
He said that about 1,400 feet of the flume has been demolished so far, and that workers from contractor Global Specialty Inc. plan to repair the flume in 1,000-foot sections. Temporary lines are being installed in the demolished portions of the flume so that water can continue to be collected and flow while the new support structures and metals boxes are put in.
The outside dimensions of the channel or boxes will remain at 14 inches by 27 inches, Ochwat said. But the inside space will be larger, increasing the maximum volume of the flow.
No modifications are being done on the system's water intakes, he added. Taylor said that an increase in the intake of water would have triggered other regulations and required additional approvals.
The flume project also calls for a boardwalk on top of the aluminum channel. It will have fiberglass grating with aluminum handrails, a far cry from the current crumbling wooden handrails and weathered timber bridges.
Because the flume is on private property owned by EMI, Ochwat said, the flume is not open to the public. He added that the flume is not safe because of cracks in the structure and its age.
"It's quite dangerous and risky to cross that flume these days because of age," he told the council members.
He added that in February about 40 feet of the flume washed away during heavy rains Upcountry. A temporary pipe has been put in place as a Band-Aid.
The flume sits at an elevation of 4,300 to 4,050 feet and within dense wet forests of ohia and native ferns and mosses. Hawaiians referred to this region as Wao Akua, a remote mountain area roamed only by spirits and thus not generally inhabited, according to the county.
The rainfall in the area averages about 250 inches per year.
According to the county, the original Waikamoi water collection system was developed in 1908. The flume was first replaced and upgraded in the mid-1930s when the County of Maui Territorial Government built the wooden flume, the one that is basically being repaired.
The last major repair work on the wooden flume was done in 1974 to 1975, the county said.
* Melissa Tanji can be reached at email@example.com.