Danger lingers for hillside homes
Yesterday's sunshine was welcome relief to homeowners in 'Aina Haina, Tantalus and Kalihi, where six weeks of rain has endangered several houses and caused many landslides and mudslides.
But homeowners living in the shadows of steep hillsides should continue to be concerned about rockfalls, landslides and mud flows, an assistant professor at the University of Hawai'i-Manoa said yesterday.
O'ahu Civil Defense officials are assessing the damage around the island to determine what needs to be done next, said Henry Eng, city Department of Planning and Permitting director.
Steve Martel, who studies rockfalls, landslides and mud flow while teaching geology and geophysics at UH-Manoa, said soil in many of the valleys around O'ahu is a very absorbent adobe clay that expands when wet then contracts when dry. That factor plus aging basalt rock that tends to crumble with time increases the chance of slope failures.
"More rain, especially of the intensity we had on Friday, could promote slope failure — landslides, rockfalls and mudslides," said Martel.
Hawai'i's climate, abundant rainfall, vegetation and steep slopes all make slopes susceptible to instability, he said.
Yesterday's sun did little to quell the fears of some residents who have mountain-side homes, mostly because it's uncertain if and when the rain will return given the recent weather pattern.
The past 43 days of rain destroyed one home in 'Aina Haina, left nine with major damage and 27 with minor damage. Also, 198 residences have either ponding in the yard, water or mud in the home, or a landslide on the property that didn't affect the home, according to the American Red Cross Hawai'i chapter.
Sally Moses, 46, who lives up Tantalus on Maunalaha Road, was standing next to a 50-yard section of hillside yesterday that had imploded during Friday's storm. She said two of her family's cars were totaled in the landslide.
Yesterday, more than a dozen Army National Guardsmen helped remove debris and clear the back of Moses' home, where the sand and land had pushed up against her windows. Shuttling between Moses' house and their staging area at the bottom of Round Top Drive, the guardsmen used an earthmover and a Humvee to maneuver through the debris.
Several guardsmen worked to erect a fence around the back of Moses' house with tin sheets and fence poles.
"We have roots here and we don't plan on leaving," Moses said. "We're not in danger (of future landslides) unless huge rains come, then we should go."
O'ahu Civil Defense officials are assessing damage around the island today, a process they began yesterday. No dollar figures have been estimated for the damage yet, partly because the city said it doesn't deal with landslides and damage that occurs on private property. The Civil Defense inspections are focusing mainly on damage to roads, sewers, culverts, drains and dams.
While the recent spate of storms hasn't been the worst the weather has dealt, it has lasted the longest, said John Cummings of the O'ahu Civil Defense Agency.
"There have been other storms that have caused a lot more damage, but it's the duration that has us taxed," he said. "We're all waiting to dry out and have it go away.
"The worst is that we fix a problem and then it rains again and then we have to come out and make the same repair again. A lot of folks have put all their efforts into this continual repair."
Martel said he believes the state would benefit if it added an office of geologic survey, where a geologist would answer questions and concerns from the public and identify areas where slides could happen.
There once was a position like that in the state, Martel said, but it was removed to save money. A resolution urging the state to study the re-establishment of a state geologist and geologic survey is being considered by the state Senate.
"Hawai'i is the only state in the country without a state geologic survey or state geologist who would field questions from the people and in matters of public safety send a surveyor out, or a team of geologists and hydrologists and cooperate with public engineers," Martel said. "The state has sufficient number of geologic hazards that it would warrant a state geologist and geologic survey."
Over the past three decades the city has been held liable when soil slipped under homes in Manoa, 'Aina Haina, Kuli'ou'ou and Palolo. The city paid $5.9 million to 11 'Aina Haina homeowners to settle a lawsuit filed after their homes began sliding down the hillside after a 1989 rainstorm.
In 2003, residents of a Hawai'i Kai townhome returned to their homes after being evacuated for a year while the developer and landowner spent $3 million to shore up a hillside after two large boulders barreled down the hillside.
And just last year three people living in an 'Aina Haina home escaped injury when the home collapsed after heavy rains pounded O'ahu just days before.
This year's damage costs could be higher.
In Kalihi Valley, a large section of hillside beneath some chicken coops in the 2600 block of Kalihi Street slid into the stream, creating a huge pile of boulders, mud and earth.
The debris is altering the water flow in the stream, and neighbors living on the other side of the stream are concerned that more rain will force water levels to rise in that area and spill into their homes. Because of the size of the slide, one man is now concerned about the stability of his son's backyard, located directly behind the landslide.
"If the rain comes I don't know," said Ernie Elido, as he sat staring at the water running by the debris pile. "I don't know how strong this one here is."
"There's not a whole lot the city can do if there's a landslide on private property," said city spokesman Mark Matsunaga. "If it's proven that there's a city responsibility for the slide, then that's different. The courts have ruled that just because the city grants a permit, it doesn't make the city liable for damages that occurred by slides."
In 'Aina Haina, Walter and Mercedes Loo, who own a home on Hao Street, have asked city officials for help in shoring up or demolishing their house after rains undercut the foundation, said their son, David. Yesterday the Loos were contacted by both the Federal Emergency Management Agency and engineers with state Civil Defense, he said.
Loo's parents are staying with relatives, he said.
"We're trying to get the city to help shore it up or tear it down," he said yesterday. "We're waiting on that."
Correction: University of Hawai'i professor Stephen Martel explained that many of the valleys on O'ahu have clayey soil that expands when wet and contracts when dry. He also said that more rain could promote slope failure, including mud flows. Homeowners noticing cracks in their homes' foundation or large cracks in the earth or hillside should contact a geotechnical specialist, not O'ahu Civil Defense. A previous version of this story contained incorrect information.