Ala Wai dredging reveals utility issue
By Walter Wright
Advertiser Staff Writer
State and Hawaiian Electric officials working on the Ala Wai Canal dredging project have discovered that two high-voltage electric cables buried in the canal are not as deep in some places as originally planned 50 years ago.
But at no time have the cables posed a hazard to anyone in or on the canal, or failed to meet government safety requirements, the officials said yesterday.
The cables across the canal originally were to be placed at a "design depth" of 16 feet below mean sea level to ensure that if the canal were dredged to a 10-foot depth there would be enough soil above them to more than meet government safety standards, HECO spokes-man Bruce Benson said yesterday.
But divers probing in the mud in February discovered that some sections of cable were at a depth as shallow as 11 feet, he said. The company then laid a series of four-ton, 8-by-20-foot concrete panels above the cables on the makai side of the canal where the dredging began to make sure they weren't accidentally snagged, and to provide protection against radiation from the high-voltage lines.
Government standards require that such cables be covered by at least three feet of soil or three inches of concrete, he said.
The panels used in this case are four inches thick.
When HECO began exploring the possibility of making the panels a permanent feature of the cable crossing, the company checked with both the Corps of Engineers and the state Department of Health and applied for additional permits to allow the panels as "fill" and to make sure the panels don't affect water quality, Benson said.
The additional permits, which have not yet been approved, do not involve electrical safety issues, he said.
He said the company and the state earlier thought the dredging permit alone was sufficient.
Andrew Monden of the state Department of Land and Natural Resources engineering office said yesterday that HECO will have to provide a permanent means of making sure the cables are under three inches of concrete or three feet of soil, even if that means burying the cable deeper in the canal.
HECO said it is working with the land agency on a plan, but hasn't settled on any one approach.
Environmental watchdog Carroll Cox, president of EnviroWatch Inc., said he has asked all parties to meet tomorrow for the purpose of "addressing and abating public safety issues" relating to the lines.
Chief DLNR engineer Eric Hirano said he appreciated Cox' inquiry and has agreed to the meeting, and that he has assured Cox that "all parties are proceeding with a plan that places safety first."
Benson said Cox's inquiries underscore the need to maintain public confidence in the safety of such installations by making sure all required procedures are followed.
He said the company is investigating why the cables are not at the 16-foot "design depth" in all locations, and speculated that the contractors in the 1950s may have run into boulders or other obstacles that prevented them from going to the full depth.
The cables are two of the three 46,000-volt lines that supply Waikiki. The third follows a land route, Benson said.
Reach Walter Wright at wwright@honoluluadvertiser.com or 525-8054.
