Crews Still Battle Sliding Hill in Diamond Bar : Damage: Slippage slows dramatically as homeowners try to assess blame. County supervisors declare a local emergency for the city and Rowland Heights.

Under rainy skies Wednesday, crews continued working to keep a sliding hill in Diamond Bar from wreaking more destruction as nearby homeowners tried to figure out who is responsible for the mess.

Also this week, the County Board of Supervisors declared a local emergency in Rowland Heights and Diamond Bar, a preliminary step to getting federal aid to help repair the slide damage. The county action came as the slide’s pace slowed dramatically, from up to four feet a day to a fraction of an inch a day.

Last week, the sliding hill jacked up Shepherd Hills Road by 10 feet, leaving nine homes reachable only by foot. The road is expected to be repaired by Friday.

The sliding dirt also crashed into back yards, destroyed gardens and twisted fences, prompting the voluntary evacuation of four families on Morning Sun Avenue in unincorporated Rowland Heights. The homeowners are uncertain when they can return and wonder about the value of their property.

“It’s now worth a penny, I guess,” said Young Kim, 57, of his 1,900-square-foot home. “It used to be a [$250,000] house.”

Kim estimates the damage to his house at more than $40,000--and says whoever is responsible for the slide should foot the bill.

Geologists are certain of one thing--shifting bedrock under the soil is triggering the slide. But they are not sure why the bedrock is moving.

Finger-pointing is reaching dizzying heights, in part because several parties have ties to the hill: the county, Diamond Bar, Walnut Valley Unified School District and a private developer.

The 100-foot-high hill is in Diamond Bar, above homes on county land. On May 17, the Diamond Bar City Council gave preliminary approval for Sasak Corp. developers to build a 21-home subdivision on a six-acre piece of the hill. As a condition of approval, Sasak agreed to post a $250,000 bond to pay for any damage from the sliding hill, which, at that point, had been moving about half an inch a day.

Next to the Sasak property, Walnut Valley Unified School District is building a middle school. In November, district contractors began moving 1 million tons of dirt to make room for the new school. Neighbors believe that the activity put pressure on the hillside, which had softened from the heavy winter rains.

An engineer for Sasak developers calls the slide an act of God. Residents say the school district is responsible, a charge that district officials deny. A Diamond Bar city councilman blames fellow council members for not acting on his May 2 request to investigate the problem and pursue remedies.

If the council had responded, said Councilman Clair W. Harmony, perhaps last week’s destruction could have been prevented. But, according to Mayor Phyllis E. Papen, council members acted on the advice of the city attorney, who noted that the homeowners live outside their jurisdiction.

“Mr. Harmony should have gotten these people in a car and gone to [County Supervisor] Deane Dana’s office a month ago,” Papen said. “They were asking the city of Diamond Bar to spend our tax dollars outside the city limits.”

Jan Dabney, chief engineer for Sasak Corp., said the school district’s bulldozing could not have caused the slide. “It’s a popular theory by some local residents. Scientifically, it has no basis,” given the bedrock’s structure, he said.

School district geologists fault heavy winter rains for the hill’s movement, said Assistant Supt. Clayton A. Chaput. He added: “We’re doing right now what we need to do to get this problem contained,” he said. “We’ll worry about assigning fault--if there is fault--later.”

The Sasak property and school site are part of an area called Sandstone Canyon. The 78-acre school site was once owned by former Diamond Bar Mayor Gary G. Miller, a Republican who is now the assemblyman-elect for the seat of recalled Assemblyman Paul V. Horcher (I-Diamond Bar).

A group of residents have fought against development of the 170-acre Sandstone Canyon, which is full of oak woodlands, mountain lions and deer.

Staff writer John M. Hubbell contributed to this story.