FOR IMMEDIATE RELEASE March 26, 2006
RAINS CAUSE WINDWARD SEWAGE SPILLS;
BROKEN KAIOLU SEWER MAIN TEMPORARILY SEALED
City Environmental Services crews responded to five sewage spills in Windward Oahu, all of them caused by heavy rains.
The spills occurred:
· A manhole at Hele Street and Keolu Drive overflowed between 9 and 11 a.m., spilling an estimated 2,400 gallons of untreated wastewater.
· A manhole near 400 Wanaao Road overflowed between 9:15 and 11:15 a.m., spilling an estimated 6,000 gallons of untreated wastewater.
· The Wanaao Road manhole overflowed again from 11:30 to 1 p.m., spilling estimated 2,700 gallons.
· A manhole on Hele Street overflowed between 9:45 and 11 a.m., spilling an estimated 1,600 gallons.
· The Waimanalo Wastewater Treatment Plant reported a spill of at least 1,000 gallons of untreated wastewater at its headworks and another spill of treated wastewater from a sand filter and injection well.
Those Windward spills all appeared to be caused by runoff from the heavy rains entering the sewage system and overwhelming its capacity. Warning signs are being posted along bodies of water affected by the spills. The state Department of Health has been notified. Water samples will be taken.
Meanwhile, repair crews unearthed the ruptured sewer main on Kaiolu Street overnight, and temporarily repaired it by sealing it in a special concrete.
Crews from the City and several contractors have been working on the 42-inch concrete main since it ruptured on Friday morning. Last night, the broken main was bypassed and additional wastewater was released intermittently into the Ala Wai Canal in order to allow crews to excavate the area around the rupture. By early evening, crews excavated enough to allow a diver from Sea Engineering to enter the pit and feel the top of the pipe, about 10 feet below street level. Working through the night, crews exposed the top half of the main and found a complex crack at a tapered joint. That ruled out a simple repair. In addition, dawn was approaching, and with it, increased wastewater flow.
Officials of the City Department of Environmental Services and Department of Design and Construction decided to temporarily seal the exposed area of the pipe in two types of lightweight concrete. This will temporarily prevent spills from the rupture.
The pressurized main was built in 1964 to carry untreated wastewater away from the Beachwalk Wastewater Pumping Station away toward the Sand Island Wastewater Treatment Plant. It handles most of the sewage generated in Manoa, Moiliili and Waikiki.
Friday’s break occurred while the Department of Design and Construction is designing a replacement main. Construction is expected to begin next year.
“This is one of the most challenging main breaks our department has faced in many years,” said Eric Takamura, PhD, director of Environmental Services. “Those challenges include the constant load on this particular system, heavy rains that added to the load and required deployment of staff and resources elsewhere, lack of alternative systems and the presence of other underground infrastructure in the immediate vicinity of the rupture.
“Despite all that, our crews and those of our contractors have performed with exemplary teamwork under adverse conditions,” he added.
Water samples are being taken by the department’s Environmental Quality Division.Warning signs have been posted along the canal and various points downstream. In addition, Environmental Services personnel have contacted canal users and are patrolling the Ala Wai banks to warn people away from the water. Surfers are being warned to avoid Ala Moana Bowls, Rock Pile and In Betweens because the current clips those surf spots near the mouth of the canal. The state Department of Health was notified and is being updated about the spill.
People should avoid contact with the waters of the Ala Wai Canal. Anyone exposed to the waters should wash thoroughly with soap and water. Objects that are exposed to the canal waters should be disinfected.
The left lane of Ala Wai Boulevard at Kaiolu continues to be closed to traffic to allow for repairs and capture of the spilled wastewater. Kaiolu Street remains closed to through traffic. Motorists should expect lane restrictions elsewhere in Waikiki for pumps to divert sewage from the broken line. The municipal parking lot at Kaiolu Street and Kuhio Avenue may be closed.
Bill Brennan, 527-6928
Mark Matsunaga, 527-5767