HomeMy WebLinkAboutPA2022-0233_20221014_Geotchnical Memo for Temporary Tarping 2022-2023 Rainy Season_10-11-22
October 11, 2022
Project No. 121.1
Log No. 1063
Gerson Bakar and Associates
c/o Park Newport Apartments
One Park Newport Drive
Newport Beach, California 92660
Attention: Ken Dressel
Subject: TEMPORARY TARP PLACEMENT
Coastal Bluff – Park Newport Apartments
One Park Newport Drive
Newport Beach, California
References: Attached
Dear Mr. Dressel:
In accordance with the request of Ms. Shawna Schaffner of CAA Planning, Rock Solid
Geotechnical, Inc. has prepared this letter regarding temporary tarp placement on selected
portions of the coastal bluff at the subject site.
We understand Park Newport Apartments intends to place slope erosion protection tarps
for the 2022-2023 rainy season.
The subject natural slope is a coastal bluff that descends to Back Bay Drive along the
eastern edge of Upper Newport Bay in Newport Beach, California. The slope descends at
slope ratios of 0.5:1 to 1.5:1 (horizontal to vertical) to locally vertical with a maximum
height of approximately 90-feet. This coastal bluff was left in a natural condition at the
time of grading/construction of Park Newport Apartments in 1969. The slope exposes 10
to 15-feet of Quaternary terrace deposits over Miocene Monterey Formation bedrock.
Numerous older landslides that exist on this slope were identified by LeRoy Crandall and
Associates, and since construction in 1969, the slope has been subjected to on-going
erosion, surficial instability, rockfalls, and landslides.
Due to the height, steep slope ratio, existing landslides, and poor quality bedrock exposed
on the coastal bluff, factors of safety for gross and surficial slope stability are less than 1.5.
The coastal bluff slope is considered grossly and surficially unstable from an engineering
geologic and geotechnical engineering perspective.
OCKSOLIDGEOTECHNICAL
949.558.9776
jamie@rocksolidgeotechnical.com
www.rocksolidgeotechnical.com
333 Third Street, Suite 2
Laguna Beach, CA 92651
TEMPORARY TARP PLACEMENT
Project No. 121.1
Log No. 1063
October 11, 2022
Page 2
There is an increased risk of impacts to Back Bay Drive and the public, if the slope
protection is not installed prior to significant rainfall. From a geotechnical perspective,
plastic erosion control tarps should be installed as soon as possible to reduce the risk to the
public and Back Bay Drive.
This opportunity to be of service is appreciated. If you have any questions, please contact
our office.
Sincerely,
ROCK SOLID GEOTECHNICAL, INC.
Jamie K. Fink
President
Professional Geologist 7626
Certified Engineering Geologist 2636
Expires 10.31.23
Sean P. Prenovost
Senior Associate Engineer
Professional Engineer 94193
Expires 12.31.2022
Distribution: 1-via e-mail Ken Dressel (Kdressel@gb-a.com)
1-via e-mail Shawna Schaffner (sschaffner@caaplanning.com)
1-via e-mail Ryan Dean (rdean@gb-a.com)
1-via e-mail Andy Dodge (adodge@gb-a.com)
333 Third Street, Suite 2Laguna Beach, CA 92651
REFERENCES
Project No. 121.1
Log No. 1063
1. “Findings and Conditions of Approval for Coastal Development Permit No CD2021-001
(PA2021-099) 1 Park Newport”, by City of Newport Beach Public Works Department,
dated May 17, 2021.
2. “Project Review Request, Community Development Department, Planning Division,
Park Newport Slope Stabilization, 1 Park Newport”, notes by Tonee Thai, dated May
18, 2021.
3. “Notice of Incomplete Filing, Application No. Coastal Development Permit 2021-
001(PA2021-099), Park Newport” by City of Newport Beach Community Development
Department, Planning Division, dated May 20,2021.
4. “Project Review Request, Community Development Department, Planning Division, Park
Newport”, notes by Sergio Gutierrez, dated May 24, 2021.
5. “Response to Coastal Development Permit Comment, One Park Newport Drive, Newport
Beach, California, CDP-2021-001 (PA2021-099)”, by Hetherington Engineering, Inc.,
dated June 8, 2021.
6. “Temporary Tarp Placement, Coastal Bluff – Park Newport Apartments, One Park
Newport Drive, Newport Beach, California,” by Hetherington Engineering, Inc., dated
October 22, 2021
7. “Bluff Stabilization Options, Coastal Bluff – Park Newport Apartments, One Park
Newport Drive, Newport Beach, California,” by Rock Solid Geotechnical, Inc., dated
August 19, 2022.
333 Third Street, Suite 2Laguna Beach, CA 92651