Rolling Hills : Slide Plan Seen as Costly

The fate of a resident’s proposal to fill canyons in an effort to stop the Flying Triangle landslide remains an open question after a second technical report--this one by the Los Angeles County Department of Public Works--concluded that the project, while promising, would be more costly and complex than envisioned. Two weeks ago, private consultants Sam W. Peterson and E. Douglas Schwantes Jr. said the buttress probably would not work and actually could accelerate movement of the six-year-old slide, which has widened over the years and has destroyed five expensive homes.

The City Council this week directed City Manager Terrence L. Belanger to review both reports and make recommendations for further action on June 9.

Frederic W. Hartwig, an engineer and Flying Triangle resident, has proposed that Klondike Canyon be filled with 224,000 cubic yards of compacted soil dumped by contractors, who would pay fees that would cover project costs. The slide is moving into both Klondike and Paintbrush canyons, and Hartwig maintains that his landfill concept could be applied to both.

The county report, while saying the buttressing concept “may be the only possible means” of slowing or stopping portions of the slide, called for additional study of such things as how much soil is needed to stop the movement, the impact of ground water on slide movement and the stability of a landfill buttress, and what impact stopping the eastern part of the slide would have on stable land. It also said that the drainage system for the fill “would have to be more extensive and sophisticated than indicated.”

Public works official Martin Murphy said all of this “would add to the cost of the project,” which Hartwig has pegged at $253,000 and Peterson and Schwantes said is closer to $1.5 million.

Hartwig sharply criticized the two private consultants, calling their warnings about possible slide acceleration “pure guesses” and labeling as wrong their conclusions that the landfill, because of poor access, would not appeal to contractors wanting to dump soil.