MAKAWAO – The leaking, redwood Waikamoi flume would be replaced with an aluminum channel supported by an aluminum truss along its entire 1.1-mile length, retaining precious surface water for drought-plagued Upcountry residents and providing a safe working platform for employees of the Department of Water Supply.
The flume channels water from the Haipuaena Stream to the vicinity of Waikamoi Stream and eventually into the water department’s upper Kula system, which supplies water to residents of Kula, Waiakoa, Keokea, Ulupalakua and Kanaio.
The $10 million to $15 million flume replacement project, which is pending necessary approvals, is expected to begin in the last quarter of this year and take about two years go complete, according to plans submitted to the state Office of Environmental Quality Control.
The office published the department’s draft environmental assessment and anticipated finding of no significant impact last week in its current issue of The Environmental Notice. It is available online at oeqc.doh.hawaii.gov/Shared%Documents/Environmental_Notice/current_issue.pdf.
Public comments are due June 22.
Maui County Council Member Joe Pontanilla, chairman of the council’s Budget and Finance Committee, said Saturday that more than $10 million has been appropriated for the flume replacement project in the current county budget.
Located in the Koolau Forest Reserve, the flume was originally built in the 1930s out of redwood timbers and rock and concrete masonry foundations, according to the draft environmental assessment. In 1974 and 1975, the flume box was replaced with redwood planking, although portions of the timber bridges that were built in the 1930s were kept in place.
“Today, due to years of weathering, the flume box and timber bridges are in poor condition,” the assessment says. “The timber flume box itself has been worn to the point where (the Department of Water Supply) estimates that during peak flows, approximately 40 percent of the water being carried by the flume is lost through various cracks and holes along with length of the timber box. Meanwhile, the timber bridges have become very dangerous for maintenance personnel to cross over.”
Project plans call for building a continuous catwalk mounted to the flume support structure to provide access along the entire length of the flume for water department employees. The catwalk will be constructed of fiberglass grating, with aluminum handrails.
The water department also plans to repair an existing access road and to set up areas where workers can lay down equipment along the flume corridor. The existing road is an unimproved dirt-and-gravel roadway that extends 3.9 miles from the mauka end of Olinda Road and runs east toward Waikamoi Stream.
The project will need to obtain a conservation district use permit from the state Board of Land and Natural Resources.
In May 2010, the state Commission on Water Resource Management directed the department to replace the Waikamoi flume structure to reduce the loss of water. The project also is consistent with the recommendations of the draft Upcountry Water Use and Development Plan.
“Completion of the project will, therefore, enable the county to install a higher level of efficiency into the existing upper Kula water system to ensure reliable provision of potable water service to existing Upcountry Maui residents for domestic and irrigation purposes,” the assessment says.
It also notes that the project “is limited to the repair and maintenance of an existing water conveyance system and is not considered a water source development venture.”
The elimination of flume leaks is expected to increase the amount of water delivered to the county’s 30-million-gallon Waikamoi Reservoirs. While the project is aimed at improving water service for residents, it’s not developing a new source of water and would “not allow for the issuance of new water meters,” the assessment says.
Public comments should be sent to: County of Maui, Department of Water Supply, 200 S. High St., Fifth Floor, Wailuku 96793 or consultant Munekiyo & Hiraga Inc., 305 High St., Suite 104, Wailuku 96793.