The third of four wells that aim to space out pumping on the south side of the Iao aquifer to help protect the main water source for Central and South Maui could go out to bid soon and possibly be operational in a year, said the deputy director of the Department of Water Supply on Thursday.
The water department submitted its draft environmental assessment for the $2.2 million project that involves turning the exploratory Wailuku Well into a production well capable of producing 1.3 million gallons of water a day.
The addition of the Wailuku Well to the system is part of an effort to retire the 6-decade-old Wailuku Shaft 33, Deputy Water Director Paul Meyer said. Shaft 33, which was built to provide water to the old Wailuku Sugar Co. fields, is currently pumping an average of 5 million gallons per day, though it has pumped as much as 11.7 million gallons daily, the draft report said.
Water flows down Iao Stream with the iconic Iao Needle in the background. The Department of Water Supply has issued a draft environmental assessment to turn the exploratory Wailuku Well into a production well. The $2.2 million effort is part of larger project to retire the six-decades-old Wailuku Shaft 33.
The Maui News / MATTHEW THAYER photo
To create "a little more gentle" way of drawing water from the aquifer, Meyer said the department is in the process of drilling four wells, each producing about 1.3 million gallons per day, to replace Shaft 33.
Shutting down Shaft 33 and redistributing the pumping was recommended by the state Commission on Water Resource Management "to better protect the aquifer," said water department spokeswoman Jacky Takakura. The commission said "it would be better if we spread the pumping out among several wells."
The draft report notes that currently there is a concentration of wells on the north side of Iao Stream, with those sources pumping about 70 percent of the 15.5 million gallons from the aquifer each day. Pumping on the south side of the stream is concentrated at Shaft 33.
Meyer also pointed out that four wells are better than one when it comes to reliability, due to redundancy.
The Wailuku Well will be the third of the four wells with Iao and Waikapu wells currently in service, but at a reduced level below their 1.3 million gallon per day yields, the draft report said. The Wailuku Well site is 1,000 feet south of the intersection of Main Street, Alu Road and Iao Valley Road in the Kehalani Mauka development above old Wailuku town.
RCFC Kehalani LLC currently owns the 12,000 square feet the county will acquire for the pump station, the draft report said.
The 582-foot well was drilled in May 2012 to determine if the site was an appropriate water source - which it turned out to be - the draft report said. In putting in the exploratory well, the hole was drilled for an 18-inch diameter casing with a portable pump installed for testing purposes.
The water department plans to install a permanent pump station with a submersible deep-well vertical turbine pump, piping, transmission lines, a control building and electrical improvements.
Meyer said that the department is going to bid on the project soon but that an operational Wailuku Well is at least "a year away." The draft report said that construction will take about eight months.
As for the fourth well, Meyer said the department is in negotiations for a site.
"We're hopeful we can get that started this year," he said.
When the four wells are completed and Shaft 33 is retired, the total draw from the four-well system is expected to be 5.2 million gallons daily, slightly more than the current 5 million gallons taken from Shaft 33.
There are about 10 water department wells drawing water from the Iao aquifer, said Takakura. The well fields include Mokuhau, Waiehu Heights, Waihee (but not the Waihee aquifer) and Shaft 33.
The water commission estimates the aquifer's sustainable yield at 20 million gallons per day. However, the commission designated the aquifer system in 2003 and limited the draw to 90 percent of sustainable yield, or 18 million gallons daily.
The current 12-month average yield is 15.5 million gallons per day, which will rise slightly to 15.7 million gallons daily when the four new wells come on line and Shaft 33 is put out of commission.
The use of public funds for the project triggered the need for an environmental assessment. The draft report is currently in its 30-day comment period.
Comments may be sent to the county Department of Water Supply, 200 S. High St., fifth floor, Wailuku 96793. The contact is Water Director David Taylor. His phone number is 270-7816.
* Lee Imada can be reached at firstname.lastname@example.org.