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CITY OF NEWPORT BEACH September 9, 2019
Community Development Dept. Project No. BL076.1
100 Civic Center Drive
Newport Beach, CA 92660
Attention: Mr. Jaime Murillo, Senior Planner
Subject: MEMORANDUM: Review of Archived Document, Slope Creep —
PROPOSED RESIDENTIAL DEVELOPMENT LOCATED at
1113 KINGS ROAD, NEWPORT BEACH, CALIFORNIA
City Project No.: PA2019-060
Associated Documents:
1. "Engineering Geologic Inspection Site of Proposed Garage, 1113 Kings Road, Newport Beach,
California, by H.V. Lawmaster& Co., Inc., dated July 25, 1973.
2. "Geotechnical Investigation for Proposed Residential Development Located at 1113 Kings Road,
Newport Beach, California," by EGA Consultants, Inc., dated January 22, 2018.
To City Planning Officials:
First, regarding the potential for on-site slope creep. Many factors can contribute to a
creep condition, such as animal burrows due to rodent activity, inadequate landscaping,
and poor on-site surface drainage. Based on the laboratory results published in our
above-referenced soils report, the site soils are not highly expansive. Therefore, a 3-ft.
thick creep zone can be used for design of caissons and on-slope structures with the
condition that surface drainage at the site must be properly provided and the slope
must be properly landscaped (such as non-homogeneous, drought-tolerant, deep-
rooted plants) and maintained.
On the basis of these anticipated conditions, any structure proposed on or near the tops
of descending slopes should be supported on deepened foundations or caissons that
extend below the creep zone in order to mitigate the potential long-term adverse effects
of slope creep.
Secondly, per the request of the client/homeowners, we have reviewed the archived
document (reference 1, above), dated July 25, 1973. Though the `73 report is based on
a site walk-through inspection (no subsurface data was collected), we are in general
concurrence with the statements regarding slope creep and stability.
In fact, the creep load soil values published in both of the above-referenced soils report
present precisely the exact same value. The `73 report allows for a creep load force of
1,000 Ibs per foot within the creep zone. Whereas, per the Executive Summary in our
report (reference 2):
375-C Monte Vista Avenue - Costa Mesa, CA 92627 - (949) 642-9309 - FAX (949) 642-1290
On-slope structures/caissons should be designed for creep loads of 1,000 lbs. per foot
of depth for the upper three feet.
Additionally, the `73 report states:
Existing conditions and slopes appear grossly stable within the site (page 2, reference 1).
Meanwhile, our soils report dated January 22, 2018 states, in general concurrence
(page 8):
Based on the extrapolation of data and geologic, the geologic structure of the bedrock
(bedding) dips at gentle angles (horizontal to 10 degrees) to the north. This structural
orientation is considered to be favorable with respect to the gross stability of the rear
and surrounding slopes underlain with bedrock.
Based on the findings of our geotechnical investigation and our professional experience
working on similar sites in the area, the proposed construction (including deepened
foundations to be supported on caissons and grade beams) will not adversely impact
the geologic stability/safety of the subject or adjoining properties.
All recommendations and soils values presented in the soils report dated January 22,
2018 (reference 2) are in accordance with the 2016 CBC, and remain valid.
This opportunity to be of service is appreciated. If you have any questions, please call.
Very truly yours,
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EGA Consultants, Inc. �� DavldA 0
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DAVID A. WORTHINGTON CEG 2124 * No' GEG2124
Principal Engineering Geologist c�A EN6n�uCF Nei 2,0
Copies. (1)Greg&Carolyn Reed CAU1 - ..=
(1)Craig Hampton,AIA `
(1)Shawna Schaffner,CAA Planning
1113 Kings Rd.,Newport Beach,CA
Reed Residence-Letter to Community Development Dept.
Project No.BL076.1
September 9,2019
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