HomeMy WebLinkAbout20170803_Response to Coastal Hazards_3-8-2017
WILLIAM SIMPSON & ASSOCIATES, INC.
CONSULTING STRUCTURAL ENGINEERS
23 ORCHARD, SUITE 250 PH. (949) 206-9929
LAKE FOREST, CA 92630 FAX (949) 206-9955
www.wsase.com e - m a i l : T mail@wsase.comT
March 08, 2017
Ian Harrison
3535 East Coast Hwy #301
Corona Del Mar, CA 92625
RE: NOTICE OF INCOMPLETE FILING
CDP No. CD2017-005
(PA2017-019)
2772 Bayshore Drive
Newport Beach, CA 92663
WSA Job #7084
Dear Mr. Harrison,
William Simpson & Associates, Inc., (WSA) is pleased to provide this letter in response to
the additional information/clarifications required in Items 8 & 9 of Notice of Incomplete Filing by
the Planning Division of the Community Development Department of City of Newport Beach
dated February 28, 2017. In addition, this letter addresses compliance with Coastal Hazards Report
requirements and standards of NBMC Section 21.30.15.E.2.
8a. A statement of the preparer’s qualifications;
Plamen Petrov, P.E., the preparer of the Coastal Hazards Report on this project, holds a
Master of Science in Structural Engineering from University of Architecture, Structural
Engineering & Geodesy of Sofia, Bulgaria, and is a Licensed Civil Engineer by the State of
California Certificate No. C66947. For the last more than 15 years of his professional career he
has been actively involved in the design and entitlement of many Waterfront Developments such
as custom homes, seawalls, piers, platforms, floating docks and marinas. A great number of
Coastal Hazards Reports prepared by him have been reviewed and accepted by California Coastal
Commission.
All of the above being said, Plamen Petrov, P.E. shall be considered a qualified preparer for
the Coastal Hazard Report on this project.
8d. On sites with an existing bulkhead, a determination as to whether the existing
bulkhead can be removed and/or a replacement of bulkhead is required to protect existing
principal structures and adjacent development or public facilities on site or in the
surrounding areas
The existing bulkhead on site is required to protect the principal structures and adjacent
developments. If it fails and does not get repaired or replaced accordingly, it would cause damage
to the neighboring properties and to the environment, and would eventually preclude the building
on the site. The damage to the neighboring properties and to the environment will consist as a
minimum of soils erosion caused by discontinuity of the seawalls which are currently continuous
along the same alignment for several properties. In other words, the erosion caused by the failed
seawall at the subject property will undermine the property line walls running in direction
perpendicular to the seawall, and will spread into the neighboring properties. Last but not least, it
would considerably decrease the size of the yard.
8e. Identification of necessary mitigation measures to address current hazardous
conditions such as siting development away from hazardous areas and elevating the finished
floor of the structures to address increased erosion and flooding due to sea level rise such as
waterproofing, flood shields, watertight doors, moveable floodwalls, partitions, water-
resistive sealant devices, sandbagging and other similar flood-proofing techniques.
The finished floor elevation of the proposed development is at +12.80’ NAVD88 which is
way above the Base Flood Elevation +9.00’ NAVD88. Since the highest high tide reached in
Newport Beach of +7.80’ MLLW is approximately 5’ below the finished floor of the proposed
development, we do not find it necessary to specify mitigation measures to address hazardous
conditions at this time.
9. Please review the requirements in Appendix A for steps 1 & 2. All to these
components should be included, and if there are components that are not applicable (e.g.
coastal bluff requirements) please state that in the report;
Requirements in Appendix A for Step 1:
Establish the project sea level rise range for the proposed project’s planning horizon
(life of project) using the current best available science.
As reflected on the enclosed Table 1 Sea Level Rise Projection for California (NRC 2012)
and Figure 3.3, over the project’s planning horizon of 75 years, the estimated Sea Level Rise is
between 1.50’ and 5.00’, which is the sea level rise for the proposed project. Based on the highest
high tides of +7.80’MLLW (+7.62’NAVD88) recorded in the project area, the above established
range of Sea Level Rise will account eventually for bay water levels in the range of
+9.12’NAVD88 and +12.62’NAVD88.
Requirements in Appendix A for Step 2:
Determine how physical impacts from sea level rise may constrain the project site,
including erosion, structural and geologic stability, flooding, and inundation.
The finished floor elevation of the proposed development is at +12.80’ NAVD88 which is
way above the Base Flood Elevation +9.00’ NAVD88. The highest high tide reached in Newport
Beach of +7.80’ MLLW is approximately 5’ below the finished floor of the proposed development.
As we well know, majority of the public streets in Newport Bay area are currently at much lower
elevations that the subject site, and will flood due to Sea Level Rise way before the development
on this site becomes subject to flooding.
Coastal Hazards report shall include (NBMC Section 21.30.15.E.2):
i. A statement of the preparer’s qualification;
See response to 8a above.
` ii. Identification of coastal hazards affecting the site;
The typical Coastal Hazards that may impact this site are waves/wakes, flooding and
erosion. Since there is no shoreline fronting the site, shoreline erosion and waves are not applicable
for this site. Boat wakes are too small to impact the development, even if the Sea Level Rise in the
next 75 years is taken into consideration. Thus, the only potential Coastal Hazard for this site is
flooding.
iii Analysis of the following conditions:
1. A seasonally eroded beach combined with long-term (75) year erosion factoring in
sea level rise;
There is no beach or shoreline fronting this site.
2. High tide condition, combined with long-term (75 year) projections for sea level rise;
As reflected on the enclosed Table 1 Sea Level Rise Projection for California (NRC 2012)
and Figure 3.3, over the project’s planning horizon of 75 years, the estimated Sea Level Rise is
between 1.50’ and 5.00’, which is the sea level rise for the proposed project. Based on the highest
high tides of +7.80’MLLW (+7.62’NAVD88) recorded in the project area, the above established
range of Sea Level Rise will account eventually for bay water levels in the range of
+9.12’NAVD88 and +12.62’NAVD88.
3. Storm waves from a one hundred year event of storm that compares to the 1982/83
El Nino event;
Due to its location, the site can’t be reached by ocean waves.
4. An analysis of bluff stability; a quantitative slope stability analysis that shows
either that the bluff currently possesses a factor of safety against sliding of at least 1.5 under
static conditions, and 1.1 under seismic (pseudostatic conditions); or the distance from the
bluff edge needed to achieve these factors of safety;
There is no bluff on this site. Thus, this condition is not applicable.
5. Demonstration that development will be sited such as that it maintains a factor of
safety against sliding of at least 1.5 under static conditions and 1.1 under seismic
(pseudostatic) conditions for its economic life (generally 75 years). Tis generally means that
setback necessary to achieve a factor of safety of 1.5 (static) and 1.1 (pseudostatic) today
must be added to the expected amount of bluff erosion over the economic life of the
development (generally 75 years);
There is no bluff on this site. Thus, this condition is not applicable.
The above answers were prepared based on the existing conditions, review and analysis of
the drawings for the proposed development on site, within the inherent limitations of this study,
and in accordance with generally acceptable engineering principles and practices. We make no
further warranty, either expressed or implied.
William Simpson & Associates, Inc. appreciates the opportunity to work with you towards
the successful completion of your project. Should you have any questions regarding this report,
please contact us.
Respectfully submitted,
Plamen Petrov, P.E. Masoud Jafari, S.E.
Senior Project Manager Principal
Enclosure:
Table 1 & Sea Level Change Graph Figure 3.3