Meeting discusses landslide causes and remedies

It was a packed house at the landslide meeting last night at White Point Elementary School to hear the results of the geotechnical report by Shannon & Wilson. City Engineer Gary Lee Moore presented the findings and long-term options.

Cause of Landslide

Storm drain separations fround prior to landslide. Click to view larger.

Nothing was found to definitively cause the landslide but several factors may have contributed to the landslide: irrigation, long-term coastal bluff erosion, precipitation, residential development, road construction, and underground utilities. The one factor that was found to not have any impact on the landslide was the Nike missile facility.

Interior of Nike missile silo at White Point. Click to view larger.

Land Movement & Water Levels
There has been no significant (> 1/10″) land movement at the monitoring sites. Ground water levels have increased by 15′ on the west side of the landslide. On the east side near residences, the ground water level has actually decreased by 1′.

Immediate Repairs
Immediate repairs will consist of grading the edge of the landslide to make it more stable. Dirt from the grading will be placed in the deepest crevices of the slide to even out the bottom. This will provide adequate surface drainage to convey water during the rainy season away from impacted areas.

Immediate repairs to surface area of landslide. Click to view larger.

A 170′ buffer zone around the slide will enable the construction of two U-turn areas. Earth anchors need to be placed into the slide area to prevent further movement. Additional monitoring wells and drains will be installed. These immediate repairs will cost approximately $5–8 million.

Proposed immediate repairs include U-turns. Cul-de-sac design could be complete in two to three months. Click to view larger.

Six Long-Term Options

  1. Do not reconnect Paseo del Mar (less than $1 million)
  2. Reroute the roadway through White Point Nature Preserve. Gates at each end of WPNP would close the road at night. ($4–8 million)
  3. Graded roadway. This slide got a good laugh at the meeting as the road looked like a skateboard half pipe. ($4–8 million)
  4. Return road to original level with retaining wall ($22–27 million)
  5. Return road to original level with no retaining wall ($42–50 million)
  6. Construct a bridge ($57–62 million)

A rerouting of Paseo del Mar would include gates for closure of the road every evening. Click to view larger.

Councilman Joe Buscaino fielded written questions from residents at the meeting. Here are a few of the questions and answers:

Q: Why was the report not released prior to the meeting so residents could ask more informed questions?
A: Changes were being made to the report over the weekend and the city attorney needed to be consulted first.

Q: Will the WPNP restrooms be connected to sewer lines prior to the Home Tour fundraiser in October?
A: This is being made a priority item. A link to the county lines would be cost prohibitive at $600,000 so other options are being considered.

Q: Will the Army Corps of Engineers be involved?
A: Congresswoman Janice Hahn has requested funding from the Army Corps on June 18th. The City Department of Engineers will be scheduling a meeting along with congressional offices.

Q: What affect will the slide have on the proposed Clearwater Project at Royal Palms and visa versa?
A: The City Department of Engineers is unfamiliar with that project.

Q: What will the decision process entail?
A: The process will be subject to some type of environmental review but maybe not an EIR. After the funding, construction usually takes three to four years.

Several requests were made by residents to work on traffic calming measures on Alma, Patton and Hamilton streets. Fire Station 101 Chief Terrazas said the narrowness of Hamilton is a problem. When another station covers for Station 101, they inform them of the alternate routes to Paseo del Mar. Residents also asked for increased police patrols on nights and weekends.

The full 800-page report can be accessed online at the City’s Dept. of Engineering website.

Media Links:
Councilman Buscaino’s video reports
KTLA5 Video
ABC7 Video
ABC7 Video – includes interview Andrea Vona of the PVPLC (update)
Daily Breeze article
KPCC article
Random Lengths News article (update)
L.A. Times article (update)
KQED article (update)

##
More landslide articles can be found on our Landslide Page. To receive instant news updates, subscribe to Email Alerts on the homepage at TheSanPedroCoast.com.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>