Engineer says slide can be fixed fixed . . . for good

Half Moon Bay Review, Jan. 3, 1995

By Robin Jones

An old solution to the perennial problem at Devil's Slide, bolstered by a small technical twist, found new supporters last week.

During Wednesday night's Mid-Coast Community Council meeting at the Seton Medical Center Coastside, Dr. John Hovland, a geotechnical engineer from Berkeley, presented his plan to permanently repair the road through the use of a drainage system, and received overwhelming support from the 30 people at the meeting.

"My first choice is to repair the road," councilmember Joe Fitting said Tuesday. "I thought (Hovland's) presentation was savvy and intelligent. I think a lot of people (who saw it) were saying, `Yeah, we thought we could do that.' "

As presented, Hovland's plan for a "well-point drainage system" consists of four or five vertical wells, all hooked up to electric pumps that would empty the wells of rainwater collected during storms.

Hovland envisions the first wells being drilled alongside the road, as "there are many areas that have significant access to the side of the road, and (the project) can be started immediately there. Anything above road-level requires more preparation of the land."

Hovland, a member of a panel of engineers that surveyed the land at Devil's Slide last winter for San Mateo County Supervisor Ted Lempert, reached his conclusions after studying data on the amount of rainfall in the Devil's Slide area every year since 1900. He discovered that the road collapses only when the area collects four inches of rain more than the seasonal cumulative mean rainfall, he said.

For example, in 1995, the area had collected 19 inches of rain by Jan. 20, and the mean rainfall to that point was only 14 inches.

"I feel perhaps that the slide has been misunderstood," Hovland said during the presentation. "I've always felt that the current road could be permanently repaired and that the slide could be stabilized."

According to CalTrans spokesperson Greg Bayol, CalTrans has been installing horizontal drains at Devil's Slide for several years, but has experienced some difficulty keeping the pipes intact.

"There's so much sliding there that whenever the land starts to move, the pipes get wiped out. That's common," Bayol said. "The drains can only go so far, and then they collapse."

Nonetheless, Hovland believes "any well installed is a step in the right direction."

"It's a hit-and-miss process," said Hovland, who studied almost 50 different landslides during the 15 years he worked for PG&E. "I think another try is worth it."

Hovland plans to write a report detailing his findings, but believes that process may be delayed if he makes more presentations at other public meetings.

Moss Beach resident Nancy Maule, who approached Hovland at the county panel's press conference in March and asked him to continue with his research, now heads a committee that hopes to garner support for the drainage solution.

"To me, (Hovland) has the answer," Maule said. "I thought (his research) was important and needed to be presented to the community. We hope to make presentations in Pacifica, Half Moon Bay, even on the Peninsula if the tunnel initiative goes through."

Hovland is currently volunteering his time to the project. Maule, for one, is thankful.

"I know that the road must be saved. Neither solution at present (tunnel or bypass) is appropriate, and both are too expensive," she said. "CalTrans owes it to us to preserve the slides in California. They can be stabilized. These areas have been here for thousands, maybe millions of years. Why destroy this asset? It's one of the most beautiful roads in the country, just a treasure."

Half Moon Bay Review