31 (067)
Susana Barrios
From:Rick Moyer <dr.rickmoyer@gmail.com>
Sent:Monday, October
To:Public Comment; Nicholas J. Taylor; Kristin Pelletier
Subject:\[EXTERNAL\] Deer Canyon Landslides
Some people who received this message don't often get email from Learn why this is important
Warning: This email originated from outside the City of Anaheim. Do not click links or open
attachments unless you recognize the sender and are expecting the message.
Dear Mayor Aitken and members of the Anaheim City Council:
According to the Deer Canyon Soils report, "Landslide Debris was mapped at the northwestern facing
slope on the Project Site, in the location between the proposed Multiple-Family Residential building and
the proposed Commercial Use Area. According to the Geotechnical Report, while no geotechnical
borings were drilled in this location, the landslide parameters appear to match the current topography
and bedding orientation. The Landslide Debris are anticipated to be largely comprised of intact
Sycamore Canyon Member. As exposed within the north facing slope, the debris are comprised of
fractured thinly bedded siltstone and sandstone. Surface raveling is prevalent and smaller inter
slides/creep is suspected".
Really? There is evidence of a landslide but no boreholes were drilled in the vicinity of the landslide
debris? Given the history of Anaheim Hills, its well documented topography and multiple documented
landslides (e.g. Santiago landslide, Pegasys landslide, Rimwood landslide, etc.), it is inconceivable that
further investigation did not occur in the form of borehole investigations at the site of the landslide
debris.
One of the most common ways to investigate a landslide is to drill boreholes but the developer admits
this was not done at the location of the landslide debris. You need to determine the depth (slip plane) of
the landslide in order to know how best to proceed with mitigation. For example, if the landslide is only a
few feet deep, a retaining wall would be adequate and relatively inexpensive. However, if the landslide is
deep or wide it may require a tie-back system in order to stabilize the earth (costly, in the millions). The
only way to know is to assess the depth. One has to wonder if the developer took a shortcut here to
avoid
the expense of putting in a tie-back system to stabilize the earth.
Please stop this project or at least postpone your decision until a definitive geologic investigation is
undertaken.
Sincerely, Rick.
--
Dr. Rick Moyer
1