1 RESOLUTION NO. 22-0062
RESOLUTION OF THE CITY OF MANHATTAN BEACH ADOPTING
AN AMENDMENT TO THE LOCAL COASTAL PROGRAM TO
INCLUDE A NEW CHAPTER TITLED SECTION VI COASTAL
HAZARDS
THE MANHATTAN BEACH CITY COUNCIL DOES HEREBY RESOLVE AS FOLLOWS:
SECTION 1. The City initiated an update to the Manhattan Beach Local Coastal Program (LCP) to address climate change, specifically sea level rise. Pursuant to the City's adopted Environmental Work Plan priorities, adopted Strategic Plan goals, and in compliance with State guidance and mandates. The City published a Sea Level Rise Risk, Hazards, and Vulnerability Assessment in June 2021 to provide a baseline of existing conditions and future vulnerability in the City of Manhattan Beach to projected sea level rise, coa stal flooding, and erosion in order to develop a range of potential adaptation strategies that address the potential future impacts from sea level rise and storms.
SECTION 2. From February through June of 2021, as part of the planning process, the City conducted nine public meetings (six workshops and three focus groups) on sea level rise, coastal adaptation strategies, the dune restoration pilot project, and climate ac tion and adaptation strategies. Over 200 members of the public participated, providing over 380 comments and questions related to sea level rise, climate action, and adaptation strategies. The City published a Sea Level Rise Adaptation Plan in November 2021 to address anticipated sea level rise and its effects on coastal erosion and flooding, following completion of the Sea Level Rise Risk, Hazards, and Vulnerability Assessment.
SECTION 3. The Planning Commission held a public study session on the Draft Coastal Hazards Section IV of the LCP on February 23, 2022 to field questions and comments on the matter after publicizing the Study Session via newspaper ads, social media, the City’s website, verbal announcements at City Council, and via email with stakeholders. The Planning Commission held a duly noticed public hearing on the Coastal Hazards Section IV of the LCP on March 23, 2022. The Planning Commission voted unanimously to adopt Resolution PC No. 22 -04, recommending adoption of the LCP amendment to the City Council.
SECTION 4 . On May 3, 2022 , the City Council held a duly noticed public h earing to consider the LCP Amendment Coastal Hazards Section IV, during which the City Council received a presentation by staff and allowed for testimony from members of the public.
The City Council also received and reviewed written testimony received by the City prior to the public hearing.
2 SECTION 5. The City Council supports the Amendment to the Manhattan Beach Phase II Local Coastal Program Land Use Plan to include Section IV Coastal Hazards (see Exhibit A), which will be organized as follows:
I. Executive Summary
II. Summary of Policies and Programs
III. Coastal Access
IV. Locating and Planning New Development
V. Coastal Marine Resources
VI. Coastal Hazards
SECTION 5. The City Council finds that the Amendments are consistent with the goals and policies of the City’s General Plan including the Community Safety Element goal one to minimize the risk to public health, safety, and welfare resulting from natural and human- caused hazards; and the Conservation of Resources goal five to conserve and protect the remaining natural resources in Manhattan Beach; and the proposed amendments are consistent with the policies of Chapter 3 of the Coastal Act.
SECTION 6 . Pursuant to the California Environmental Quality Act (CEQA), local governments are exempt from the requirement of preparing an environmental impact report (EIR) in connection with activities and approvals necessary for the preparation and adoption of LCPs and LCP amendments. Instead, the CEQA responsibilities are assigned to the CCC; however, the CCC's LCP review and approval program has been found by the Secretary of the Natural Resources Agency to be functionally equivalent to the EIR process.
SECTION 7. Based upon the foregoing, the City Council hereby adopts Section IV Coastal Hazards as an Amendment to the Local Coastal Program, incorporated herein by reference and as “Exhibit A.” Should the California Coastal Commission require substantial changes to the LCP Amendmen t adopted herein, staff shall bring such changes back to the City Council for review and adoption.
SECTION 8. The City Council’s decision is based upon each of the totally independent and separate grounds stated herein, each of which stands alone as a sufficient basis for its decision.
SECTION 9. The City Clerk shall certify to the adoption of this Resolution. 3 ADOPTED on May 3, 2022.
AYES:
NOES:
ABSENT:
ABSTAIN:
__________________
HILDY STERN
ATTEST: Mayor
_______________________
LIZA TAMURA
City Clerk
Exhibit
Exhibit A: LCP Amendment Section IV Coastal Hazards
Sea Le
vel Rise Policies City of Manhattan Beach
Local Co
astal Program Update 1
SEC
TION VI
C
OASTAL HAZARDS
I. INTR
ODUCTION
Thi
s section documents coastal hazards present in Manhattan Beach, including flooding and shoreline hazards. It establishes policies that address the safety of community members and mitigate potential impacts from natural and man-made hazards.
In addition, this chapter discusses the types of shoreline protective devices currently in place within the coastal zone and policies for maintaining, rebuilding, or installing new devices.
Manhattan Beach has experienced numerous coastal storm events over the past few decades that caused flooding and erosion damage. In the late fall and winter of 1982/1983, California experienced an El Niño1 tha t produced significant precipitation,
strong winds, and high surf along southern California. The storms damaged coastal structures and eroded beaches. Waves reached the Pier deck and damaged the iconic Pier. The Pier deck, Roundhouse Aquarium, and lifeguard station at the beginning of the Pier were completely replaced2. Othe
r notable El Nino seasons occurred in 1998 and 2010. In 2017, surf reached 15 feet at El Porto Beach in North Manhattan Beach3.
II. SET
TING
TID
AL INUNDATION AND COASTAL STORM FLOODING HAZARDS
Flooding i
s inundation of normally dry land as a result of a rise in the level of surface waters or rapid accumulation of stormwater runoff. The Federal Emergency Management Agency (FEMA), through its Flood Insurance Rate Mapping (FIRM) program, designates areas where urban flooding could occur during 100-year and 500-year flood events (1 percent and 0.2 percent annual probability of occurrence, respectively). FEMA categorizes flood-prone areas as follows: Coastal Flooding; River Flooding; and Creek Flooding. Flood zones in the coastal zone are concentrated along the coastline. FEMA mapping shows that the entire sandy beach coastline is within the 1% annual chance flood zone, and anticipated flood water elevations during the 1% flood event in Manhattan Beach range from 16 feet to 20 feet NAVD88
4. Future
sea level rise is expected to create a permanent rise in ocean water levels that would shift the water’s edge landward. If no action is taken, higher water levels would increase erosion of the beach, cause a loss of sand, and result in a narrower beach. Additionally, the combination of higher ocean water levels and beach erosion would result in greater flooding and damage during coastal storms and high tide events. The City of Manhattan Beach Sea Level Rise Risk, Hazards, and Vulnerability Assessment
5 (Sea
Level Rise Vulnerability Assessment) and associated mapping identifies the progression of coastal erosion under different sea level rise scenarios. 1 El
Niño is the warm phase of the El Niño-Southern Oscillation and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific. The warmer waters cause the Pacific jet stream to move south often resulting in wetter winters and increased flooding in the southern United States.
2 Manh
attan Beach Historical Society. 2021. https://manhattanbeachhistorical.org/pier/ Accessed August 2021. 3 B
arnes, M. 2017. Daily Breeze. January 22, 2017. https://www.dailybreeze.com/2017/01/22/storm-slams-south-bay-more-than-3-inches-of- ra
in-causes-widespread-flooding/. Accessed August 2021.
4 No
rth American Vertical Datum of 1988.
5 ESA
. 2021a. City of Manhattan Beach Sea Level Rise Risk, Hazards, and Vulnerability Assessment. Prepared for the City of Manhattan Beach.
May 2021.
Sea Level Rise
Policies
City of Manhattan Beach
2 Local Coastal Program Update
To assess vulnerabilities for the City of Manhat
tan Beach, f
ive
sea level
rise
scenarios
, in addition to existing conditions, were
mapped
: 0, 2.5, 4.1, 5.7, 6.6, and 9.8 feet
(0, 0.75, 1.25, 1.75, 2.0, and 3.0 meters)
. The scenarios were chosen based on State
guidance
using
the
O
cean
P
rotection
C
ounci
l
6 (
OPC)
projections and available
model runs
from the Coastal Storm Modeling
System (CoSMoS) developed by the United States Geologic Survey.
With future climate change and
sea
level
rise, the
city
of
Manhattan Beach’s current vulnerabilities
are projected
to increase
in
both frequency and intensity.
However, it’s notable that the City’s vulnerabilities are relatively limited ,
compared to other
jurisdictions statewide
, and centered around public assets and not private development.
T
he following are the publi
c
assets
most vulnerable to sea
level rise hazards
based on the
Sea Level Rise Vulnerability Assessment
:
Marvin Braude bike trail
: expected to be vulnerable to wave runup during a 100
-
year storm event with 4.9 feet of sea
level rise.
Public restrooms
at El Porto Beach
:
not expected to be vulnerable to wave runup
until 4.9 feet of sea level rise
but
could experience storm inundation with 4.9 feet of sea level rise; not expected to experience daily tidal inundation with
up to 9.8 feet of sea level rise (the highest amount of sea level rise analyzed in the Sea Level Rise Vulnerability Assessment).
Public restroom and m
aintenance building at Rosecrans Avenue
: already vulnerable to wave runup during a 100
-
year
storm event a
nd
could be exposed to more extensive storm inundation with 3.3 feet of sea level rise, and daily tidal inundation between 6.6 and 9.8 feet of sea level rise.
Public restrooms at the Pier:
not expected to be vulnerable to wave runup
until 1.6
feet of sea l
evel rise but could
experience storm inundation with
3.3 feet of sea level rise; not expected to experience daily tidal inundation with up to 9.8 feet of sea level rise (the highest amount of sea level rise analyzed in the Sea Level Rise Vulnerability Asse
ssment).
Food stand and beach rental building at El Porto Beach
: already vulnerable to wave runup during a 100
-
year storm
event;
could be exposed to more extensive storm inundation with 3.3 feet of sea level rise and daily inundation with
6.6 feet of sea l
evel rise.
Lower Pier Parking Lot
:
expected to be vulnerable to wave runup during a 100
-
year storm event with 4.9 feet of sea
level rise; not expected to experience more extensive storm inundation until after more than 9.8 feet of sea level rise.
Municipal
Pier
:
specifically designed and intentionally located to b
e in the potential hazard zones,
h
owever, over
time, the exposure of the structure to waves and large storm events will increase. Additionally, the assets at the pier (e.g., Roundhouse Aquarium) wi
ll experience more frequent wave overtopping with sea level rise.
Storm Drain Outfalls
: expected to be vulnerable to beach erosion and sand blockage with sea level rise. This may lead to more frequent maintenance to remove sand from the outfall before anticipated rainfall events.
South Bay Cities’ Main Sewer Trunk Line
: not expected to reach the sewer line under 6.6 feet of sea level rise, but water levels during a 100
-
year storm could extend to the sewer line between 27
th
and 32
nd
Streets and around Ma
rine
Avenue. Higher water levels could limit access to the line for maintenance and operation or inundate maintenance holes and increase flows in the system that the treatment plant would then have to process.
Beach
: sea level rise will cause increased lev
els of erosion (see Beach Erosion section below).
6 California OPC and California Natural Resources Ag
ency. 2018. State of California Sea
-
Level Rise Guidance 2018 Update.
Sea Level Rise
Policies
City of Manhattan Beach
Local Coastal Program Update
3 The
Coastal Act
provides the basis, authority, and regulatory framework for
LCP
Land Use Plan
policies to
address
sea level
rise. Additionally, the California Coastal
Commission Sea Level Rise Policy Guidan
ce
7 provides information for local
municipalities
amending
LCPs
. The guidance document recognizes that the Coastal Act
supports:
(
1)
using
best available
science to guide decisions
;
(2)
minimiz
ing
coastal
hazards through planning and development standards;
(
3) maximiz
ing
protection of
coastal resources, including
public
access
and
recreation,
coastal habitats, Environmentally Sensitive Habitat
Areas and wetlands, water quality and supply, archaeology and paleontological resources, and scenic and visual coas
tal
resources
;
and
(
4) maximiz
ing
agency
coordination and public participation.
Coastal Act policies are incorporated into this LCP by reference.
Coastal Act policies
relating to shoreline
protection
require
that
development that alters natural
shoreline processes
, such as seawalls
and retaining walls
, be permitted
only
where
required to
serve coastal
-
dependent
uses or protect existing structures or
public
beaches in danger from erosion
,
and when
designed to eliminate or mitigate adverse impacts
on local shoreline sand supply
(Public Resources Code
§30235). Further,
other coastal policies require that
new
development, such as shoreline
protective devices, a
s well as
other
activities
, be sited
and designed to:
1. Prevent significant disruption to or d
egradation of Environmentally Sensitive Habitat Areas (Public Resources Code §30240).
2. Mitigate adverse impacts to archeological and paleontological resources (Public Resources Code §30244).
3. Protect ocean views, minimize the alteration of natural land forms , and be visually compatible with and subordinate to
the surrounding character of the area (Public Resources Code §30251).
4. Provide, and not interfere with, maximum public recreational access to and along the shoreline (Public Resources Code §§30210, 30211,
and 30212).
Finally, Coastal Act policies require that all new development minimize risks to life and property
in
areas of high geologic and
flood hazard areas (
Public Resources Code §30253(a)) and not create, nor contribute significantly
to, erosion,
ge
ologic
instability,
or
destruction of a site
or surrounding area or in any way require the construction of protective devices that would substantially alter natural landforms along bluffs and cliffs
(Public Resources Code §30253(b)).
Figure 1
-
1 and
1 -
2 de
pict areas where
daily
tidal
inundation could potentially
occur
in the future with
sea level
rise.
Figures 1
-
3 and 1
-
4 show the maximum modeled flood extent
for the 1
percent
annual chance coastal storm flood event
(i.e., the upper
range of the
CoSMoS uncertainty bounds, which includes uncertainty due to vertical land motion changes, model performance and elevation measurements) to understand the full range of potential exposure.
The
se
m
ap
s
provide
a
screening
-
level tool
that depicts where site s
pecific technical evaluations may be required and where development standards pertaining to shoreline hazard areas may be applied.
EXTREME RAINFALL HAZARDS
Stormwater infrastructure in coastal cities is usually designed to drain rainfall based on a fixed ocean water level (i.e., the design
usually assumes
sea
water levels are low enough to allow full drainage from the pipes). However, the co -
occurrence of extreme
rainfall and high ocean water levels can lead to increased flood risk. With rising sea levels,
Manhattan Beach may experience
increased
flooding from rainfall events due to the blockage of the outfalls by higher -
than
-
normal coastal water levels
moving up
7 California Coastal Commission. 2018. California Coastal Commission Sea Level Rise Policy Guidance, Interpretive Guidelines fo r Addressing
Sea Level Rise in Local Coastal Programs and Co
astal Development Permits. July 2018.
Sea Level Rise
Policies
City of Manhattan Beach
4 Local Coastal Program Update
into the storm drain system.
In this situation, reduced outflow capacity at the ocean outlet ma y propagate through the system
leading to extensive floo
ding inland
.
The Sea Level Rise Vulnerability Assessment included an analysis of the co -
occurrence of extreme rainfall and high ocean
water levels for Manhattan Beach. Model results for existing conditions (i.e., current climate conditions) show that the stormwater system can pass the current 25
-
year rainfall event with limited flooding, but that the 50 -
and 100
-
year rainfall
events would result in widespread flooding even without a higher coastal
water level. During these events, water is expected
to back up into the system and flood through maintenance holes because the pipes cannot move the water to the ocean quickly enough.
The model results also show that future sea levels without a rainfall event are not expected to lead to substantial flooding of the stormwater system, primarily because the storm drain system is elevated enough above the outfalls.
However, the
flooding caused by the co
-
occurrence of high ocean water levels and increased inte nsity of rainfall storms is expected to get
worse in the future.
R
osecrans Ave
H
ighland Ave
4 5th St
M
arine Ave
T
he Strand
/
0 8/07/2019
C
urrent Day
7 5 cm (2.5 ft) SLR
1 25 cm (4.1 ft) SLR
1 75 cm (5.7 ft) SLR
2 00 cm (6.6 ft) SLR
3 00 cm (9.8 ft) SLR (H++ proxy)
Figure 1-1
Tidal Inundation with Sea Level Rise in
North Manhattan Beach
M
arine Ave
M
anhattan Beach Blvd
1 st St
T
he Strand
/
0 8/07/2019
C
urrent Day
7 5 cm (2.5 ft) SLR
1 25 cm (4.1 ft) SLR
1 75 cm (5.7 ft) SLR
2 00 cm (6.6 ft) SLR
3 00 cm (9.8 ft) SLR (H++ proxy)
Figure 1-2
Tidal Inundation with Sea Level Rise in
South Manhattan Beach
R
osecrans Ave
H
ighland Ave
4 5th St
M
arine Ave
T
he Strand
/
0 8/07/2019
C
urrent Day + 100 yr storm (max)
7 5 cm (2.5 ft) SLR + 100 yr storm (max)
1 25 cm (4.1 ft) SLR + 100 yr storm (max)
1 75 cm (5.7 ft) SLR + 100 yr storm (max)
2 00 cm (6.6 ft) SLR + 100 yr storm (max)
Figure 1-3
Coastal Storm Flooding with Sea Level
Rise in North Manhattan Beach
M
arine Ave
M
anhattan Beach Blvd
1 st St
T
he Strand
/
0 8/07/2019
C
urrent Day + 100 yr storm (max)
7 5 cm (2.5 ft) SLR + 100 yr storm (max)
1 25 cm (4.1 ft) SLR + 100 yr storm (max)
1 75 cm (5.7 ft) SLR + 100 yr storm (max)
2 00 cm (6.6 ft) SLR + 100 yr storm (max)
Figure 1-4
Coastal Storm Flooding with Sea Level
Rise in South Manhattan Beach
Sea Level Rise
Policies
City of Manhattan Beach
Local Coastal Program Update
9 BEACH EROSION HAZARDS
Beach erosion is a complex response to many processes including marine, terrestrial, and other instabili ties such as seismic
shifts and biologic changes. In general, under natural conditions, sand is provided to beaches by sediment transport along th e
coast
and from the back beach
through wave action as well as from deposition through rivers and streams that
empty into the
ocean
. Winter storms tend to cause heavy wave action which reduces sand content at beaches that will typically recover during milder summer conditions.
Manhattan Beach
i
s part of the
Santa Monica
Littoral Ce
ll, which spans approximat
ely 49
miles from
Point Dume to Palos
Verdes Point
. In general, studies have found that the sand predominantly moves downcoast (south) t hrough this littoral cell.
The Manhattan Beach
coastline
is characterized by sandy beach
. The c
oastal zone within the
city of Manhattan Beach
slopes
up from the beach
with
elevations quickly rising out of the flood zone behind the beach .
In general, historic erosion rates in Manhattan Beach show net accretion over time (i.e., beach widening), likely due to the extensive
beach nourishment
historically
in Santa Monica Bay and the construction of sand retention structures downcoast of the City. The
Sea Level Rise
Vulnerability Assessment provides an analysis of projected beach widths with sea level rise 8 .
Table
1 -
1 presents
the beach erosion over time, if no
adaptation
action
s
are
taken.
T
ABLE
1 -
1 :
B
EACH
W
IDTH
E
VOLUTION
YEAR
TOTAL BEACH WIDTH (F
T)
% LOSS
2020
370
0%
2030
360
2%
2040
350
5%
2050
330
11%
2060
310
16%
2070
290
22%
2080
260
29%
2090
230
37%
2100
200
47%
Note, Table 1
-
1 provides the average beach width over time
, assuming a sea
level rise of
6.8 feet by
2100
,
and does not account
for erosion during episodic storm events. Typical seasonal oscillations of the shoreline are around 30 feet in Southern Calif
ornia
but
large coastal storm events can
cause larger oscillations with the beach
erod
ing
by as much as 100 feet.
GROUNDWATER HAZARDS
Rising sea levels can impact coastal groundwater both by increasing groundwater levels and by
the intrusion of salt water
into
coastal aquifers. Higher sea levels cause inland intrusion of denser salt water, which can raise unconfined salt water tables
and also force overlying freshwater to rise up. As the water table rises, it can rise above the ground surface, flooding low -
lying
8 The OPC 2018 medium
-
high risk aversion sea level rise scenario was used for this analysis.
Sea Level Rise
Policies
City of Manhattan Beach
10 Local Coastal Program Update
areas or it can infiltrate and damage shallow infrastructure, such as basements, building foundations, and gas lines.
Additionally, the intrusion of salt water can impact drinking water supplies
.
In the
Sea Level Rise
Vulnerability Assessment, the de
pth to groundwater
with increasing sea levels
was evaluated across
Manhattan Beach.
Because the land slopes up quickly from the beach, the groundwater under most of the city is deep and there is limited risk to inland flooding.
While there is not expected
to be any emergence of groundwater leading to backshore ponding in Manhattan Beach, it is possible that
groundwater could
impact underground infrastructure
,
such
as sewer and
electrical lines
, but not until after 9.8 feet of sea level rise
.
ADAPTATION STRATEGIES
Some
adaptation strategies have already been implemented
in Manhattan Beach
to reduce vulnerabilities to coastal hazards
along the City’s shoreline.
There are also other adaptation strategies used by adjacent jurisdictions, such as bu ilding seasonal
sand berms, beach nourishment, and wetlands restoration.
A
pproximately
23 % of the Manhattan Beach coastline is protected by coastal armoring structures such as rock revetments
(north end of El Porto Beach)
and concrete sea walls
(El Porto
Beach and near the Pier)
.
An inventory of shoreline protective
devices was developed in 2005 by NOAA for
the entire California coastline and updated
for Manhattan Beach
by
ESA
in the
Sea
Level Rise
Vulnerability Assessment.
While sea walls and revetments p
rovide protection to existing shoreline development,
these structures can contribute to
beach
erosion
and accelerate beach loss.
Beach d
une restoration is recognized as a natural way of mitigating backshore erosion ,
as well as maintaining a wider beach
by
creating an additional source of sand at the back of the beach, while increasing local sand retention.
When dunes are
allowed to form and create natural features
they provide a cost
-
effective buffer of protection from
sea level
rise and storm
erosion.
The
Manhattan Beach Dune Restoration Project
9 will enhance approximately
three
acres of existing dunes in
Manhattan Beach from 36th Street to 23rd Street, across approximately 0.6 miles of coastline .
The Manhattan Beach Dune
Restoration Project
,
led by The Bay Foundation in partnership with Los Angeles County Department of Beaches and Harbors, the
City of Manhattan Beach, and
the
California State Coastal Conservancy, is currently
in
the
permitting
stage (as of
December
2021).
The g
oal of this dune restoration
living shoreline
project is to increase the resiliency of the beach
through the
restoration of sandy beach and foredune habitat, implement nature -
based protection measures against sea level rise and
coastal storms, and increase
engagement of the community through enhanced beach experiences .
Manhattan Beach has two active groundwater wells used for drinking water: Well 11A and Well 15. Well 11A is located on the southwest corner of Manhattan Beach Boulevard and Green Lane and We ll 15 is located on the southwest corner of Manhattan
Beach and Vail Avenue. As a result of pumping out large amounts of fresh groundwater along the coast, salt water from the ocean began to intrude into the spaces left by removal of the groundwater, movin g salt water into the groundwater basin in
the 1940s. In the early 1950s, the West Coast Basin Barrier Project (WCBBP) was constructed to prevent ocean water from intruding into the underlying aquifers of the West Coast Groundwater Basin, which spans from just south of Ballona Creek
through Long Beach. The WCBBP injects mostly recycled water into the groundwater basin to push salt water back towards the ocean. In Manhattan Beach, the injection wells are located between Valley Drive and North Ardmore Avenue.
The WCBBP is
operated by the West Basin Municipal Water District.
9 https://www.santamonicabay.org/explore/beaches
-
dunes
-
bluffs/beach
-
restoration/manhattan
-
beach
-
dune
-
restoration
-
project/manhattan
-
beach
-
dune
-
restoration
-
project
-
faq/
Sea Level Rise
Policies
City of Manhattan Beach
Local Coastal Program Update
11 The City of M
anhattan Beach Sea L
evel Rise Adaptation Plan
10 (Adaptation Plan)
identifies a variety of
additional
adaptation
measures that should be considered as options for responding to s ea level rise related hazards.
The Adaptation Plan provides
a framework for the City to monitor effects of coastal erosion a nd flooding with sea level rise and
prepare for identified
vulnerabilities
by
choos
ing
from a toolbox of adaptation measures.
As a
guidance document, t
he Adaptation Plan
provides
flexibility for the City to choose
appropriate
adaptation measures over time
,
as specified thresholds
for action
are reached.
III.
C
OASTAL HAZARDS AND ADAPTATION POLICIES
A.
NATURAL MANAGEMENT OF
COASTAL HAZARDS
The Natural Management of Coastal Hazards
policies call for non
-
structural adaptation strategies, such as a beach dune
program, winter
sand berms,
establishment of
off
-
shore reefs
and kelp beds
, and managed retreat (accepting
a narrower
beach).
Policy IV.A.1:
Maximize natural shoreline values and processes; minimize the perpetuation of shoreline armoring .
Policy IV.A.2:
Develop and implement a beach dune
and living shoreline
restoration
program
.
The continued viability of
dune and other coastal habitats shall
be provided for by planning for inland migration and/or replacement of habitats lost to sea level rise.
Policy IV.A.3:
Stabilize dunes and back beach with
the installation and maintenance of drought
-
tolerant native coastal
vegetation capable of enhancing dune stability
and the removal of non
-
native vegetation
.
Development
shall
be set back from dunes through buffers of sufficient width and design to pr otect native
costal
vegetation
from impacts of adjacent uses, including
a
bike path
set back
of
a minimum of
three feet and
a
beach grooming
set back
of
a minimum of
five feet.
Policy IV.A.4:
T
he beneficial reuse and placement of sediments for sand nourishment projects should use beach -
quality
sand to enhance the use, safety, and appearance of the City’s beaches when adverse impacts to the beach, intertidal, offshore resources, and surf are mini
mized and avoid significant disruption to marine and
wildlife habitats and water circulation. Any beach nourishment project shall protect water quality and
minimize and mitigate potential adverse biological
and recreational
resource impacts
by
consider
ing
the
method, location, and timing of placement.
Policy IV.A.5:
Participate in
a
ny
Regional Sediment Management (RSM) program
s
for beach sand replenishment and
retention
.
Participate in and encourage other long
-
term beach sand replenishment and retention pr
ograms
at the federal, state, and regional level.
Policy IV.A.6:
Support giant kelp reforestation programs
, including
through minimization of dredging activities,
suspended sediment loads, and urban runoff
.
Policy IV.A.7:
I
mplement eelgrass restoration and
enhancement programs
to
protect eelgrass meadows for their
important ecological function as a nursery and foraging habitat within the Manhattan Beach ecosystem .
B.
SHORELINE PROTECTION DEVICES
The Shoreline Protection Devices
policies relate to en
gineered structural protective devices, such as groins, seawalls, or rock revetments. As detailed in the Adaptation Plan, seawalls and revetments can contribute to erosion and accelerate beach loss.
10 ESA. 2021b. City of Manhattan Beach Sea Level Rise Adaptation Plan. Prepared for the City
of Manhattan Beach. July 2021.
Sea Level Rise
Policies
City of Manhattan Beach
12 Local Coastal Program Update
T
herefore
,
the
policies
limit construction of
new
shoreli
ne protection devices
, while also minimizing the effects of any such
approvable developments
.
Policy IV.B.1:
Limit
shoreline protection devices
, including revetments, breakwaters, groins, seawalls, and other such construction that alters natural shoreline processes.
When required to serve coastal
-
dependent uses or
protect existing principal structures or public beaches in danger from erosion, site shoreline protection
devices to avoid sensitive resources, if feasible, and
mitigate
adverse impacts on all coastal resour
ces
.
Policy IV.B.2:
Discourage shoreline protective devices on public land. Such protective devices
shall only
be
permitted if
no other less environmentally damaging alternative
is available, including
avoidance, restoration of the
sand supply, beach nourishment, and planned retreat
.
Policy IV.B.3:
When
allowed, shoreline
prot
ection devices shall be designed to blend visually with the natural shoreline, provide for public recreational access.
If impacts cannot be avoided, they shall be mitigated through options such as providing equivalent new public access or recreational faci lities or undertaking restoration
of nearby beach habitat. If such options are not feasible, proportional in -
lieu fees that consider the full
value of the beach
–
including with respect to impacts on shoreline sandy supply, sandy beaches, public recreation
al access, public views, natural landforms, beach ecology, and water quality –
may be used as a
vehicle for impact mitigation provided that such in
-
lieu fees are deposited in an interest bearing account
managed by the City of Manhattan Beach and used only
for acquisition or improvements of co
a
stal public
access, biological restoration, or other relevant mitigation in the vicinity of the project.
Policy IV.B.4:
Require modifications to existing shoreline protective devices to ensure that such devices are functioning
in a way that has the least impact on coastal resources
such as recreation, public access, and coastal
resources
as possible, including evaluation of possible removal and shoreline restoration .
A
ny permittee of
a protective device shall be responsible for removing all recoverable debris associated with the development from the beach or ocean and lawfully dispose of the material in an approved disposal site.
C.
SHORELINE REDEVELOPMENT AND NEW DEVELOPMENT
The Shoreline Development
policies address
both
redevelopment
11 of existing buildings
/facilities along the
coast
and
new
coastal
development
.
The
policies
are intended to
guide future development in a manner that minimizes hazard risk and is
11 Redevelopment: A development proposal reaches the threshold of being a replacement structure or redevelopment if it meets cri teria a
)
or
b
).
Development meeting this definition must be brought into conformance with all coa stal resource protection policies in this LCP.
a)
Development that consists of alterations including (1) additions to an existing structure, (2) exterior and/or interior renov ations,
and/or (3) demolition or replacement of an existing home or other princi pal structure, or portions thereof, which result in either:
1)
Replacement (including demolition, renovation or alteration) of 50% or more of major structural components including exterior walls, floor, roof structure or foundation, or a 50% increase in gross floor area. Alterations are not
additive between individual major structural components;
or
2) Replacement
(including demolition, renovation or alteration) of less than 50% of a major structural component where the proposed replacement would result
in cumulative alterations exceeding 50% or more of that major structural component, taking into consideration previous replacement work undertaken on or after January 1, 1977; or an alteration that constitutes less than 50% increase in floor area where the
proposed alteration would result in a
cumulative addition of 50% or greater of the floor area, taking into consideration previous additions undertaken on or after January 1, 1977
. OR
b) Development
that consists of any alteration of a structure, the cost
of which equals or exceeds 50 percent of the market value of the structure before the start of construction, based on the documented construction bid costs and either an appraisal by a professional property appraiser or County assessor data, if it is base d on current market values
.
Sea Level Rise
Policies
City of Manhattan Beach
Local Coastal Program Update
13 capable of adapting to future shoreline conditions without the need for protection.
Refer to Figures 1
-
1 through 1
-
4 for
the
mapped c
oastal hazard
areas
that are
referenced
in policies
below
.
Policy IV.C.1:
Avoid
coastal hazard risks and
minimize
resource impacts when making redevelopment
decisions.
New
development shall do all of the following:
Minimize risks to life and property in areas of
high geologic, flood, and fire hazard.
Assure stability and structural integrity, and neither create nor contribute significantly to erosion, geologic instability, or destruction of the site or surrounding area or in a way require the construction of prote
ctive devices that would substantially alter natural landforms along bluffs and cliffs.
Where appropriate, protect special communities and neighborhoods that, because of their unique characteristics, are popular visitor destination points for recreational uses.
Policy IV.C.2:
Development
should be sited to avoid coastal hazard areas
including wave, flooding, and erosion zones as
they move inland within the
expected duration of the development
(see the Sea Level Rise Vulnerability
Assessment for additional information about the coastal hazard zones and sea level rise timing )
.
A site
-
specific
coastal hazards report prepared by a qualified geologist/engineer would be required to ensure that such development can be built in a man
ner consistent with applicable LCP coastal hazard policies for any new development and redevelopment within the mapped hazard areas in Figures 1 -
1 through 1
-
4. If
avoidance
of coastal hazard areas
is infeasible, development should have a design
resilient t
o flooding and
erosion
to minimize impacts to public safety and property without reliance on current or future shoreline protection features
.
The design of the development should also
minimize
unavoidable coastal resource
impacts, including impacts
to coastal access and recreation, environmental resources, and visual resources. For cases where resilient design may not be enough to address sea level rise impacts over the full life of the structure, the applicant shall develop a long -
term plan that ide
ntifies future adaptation
strategies (potentially up to and including relocation) to address sea level rise and coastal resource impacts
.
Policy IV.C.3:
Site and design new structures to avoid the need for shoreline protective devices during the economic l ife
of the structure
.
Applicants for new development and/or redevelopment are required to waive any rights that may exist under Section 30253 of the Coastal Act, which requires new development to assure stability and structural integrity withou
t reliance on shoreline protective devices.
Typical economic lifetimes of
development
include
:
Ancillary development or amenity structures (e.g. trails, bike racks, playgrounds, parking lots, shoreline restrooms): 5
-
25 years
Manufactured or mobile homes: 30
-
55 years
Residential or commercial structures: 75
-
100 years
Critical infrastructure: 100
-
150 years
P
ermit applicants are required to record a deed restriction again the properties involved in the application acknowledging that the structure may be required to be removed or relocated and the site restored if it becomes unsafe. Removal would only be necess
ary if other adaptation strategies contemplated in the
Adaptation Plan do not work.
Sea Level Rise
Policies
City of Manhattan Beach
14 Local Coastal Program Update
Policy IV.C.4:
As
a condition of approval of development on a beach or shoreline which is subject to wave action, erosion, flooding, or other hazards associated w
ith development on a beach in which avoidance is infeasible, the property owner shall be required to execute and record a deed restriction which acknowledges 1) the
development is located in a hazardous area or an area that may become hazardous in the futu re; 2) that
sea level rise could render it difficult or impossible to provide services to the site; 3) that the boundary between public tidelands and private land may shift with rising seas and the development approval does not permit encroachment onto pub
lic trust land; 4) that additional adaptation strategies may be required in the future to address sea level rise consistent with the Coastal Act and certified LCP.
Additionally, the
deed shall acknowledge
said risks and waives any future claims
of damage or liability against the
permitting agency and agrees to indemnify the permitting agency against any liability, claims, damages or expenses arising from any injury or damage due to such hazards.
Policy IV.C.5:
Monitor
the frequency of maintenance required for storm drains to identify when further improvements and adaptation actions (including shortening the outfalls) are needed due to vulnerabilities from beach erosion and sand blockage with sea level rise.
Refer to th
e Adaptation Plan for more information on
the
triggers that indicate the need for
adaptation actions.
Future projects, such as stormwater infiltration
projects along the backshore, should consider sea level rise during feasibility assessments
and
inc
lude
measures to minimize impacts from coastal hazards as well as avoid impacts to water quality, public access, scenic and visual resources, and other coastal resources .
Policy IV.C.6:
New public beach facilities shall be limited to only those structures which provide or enhance public
recreation activities
and only when
alternative sites upland of the beach are not feasible
.
D.
PUBLIC ACCESS, RECREATION, AND SENSITIVE COASTAL RESOURCES
The Public Access, Recreation, and Sensitive Coastal Resources policies aim
to
protect public access, recreation, and sensitive
coastal resources, which are identified by the California Coastal Commission (CCC) as
necessary considerations in plans
addressing sea level rise in the coastal zone.
Policy IV.D.1:
Avo
id
impacts to beach dune habitat when designing and siting recreation areas, and d irect public access
to
use well
-
defined footpaths
and the Strand rather than over dune habitat areas through symbolic/
protective fencing, signage, and similar methods.
Policy IV.D.2:
Consider options to retrofit or relocate recreation and visitor serving facilities to avoid
sea level rise
impacts
and
maximum
opportunities
for coastal access and recreation
.
Policy IV.D.3:
New development and redevelopment shall
maximize
public coastal access to the maximum extent
feasible
(unless public access would pose a safety risk or threat to fragile resources, or where adeq uate
access exists nearby, consistent with the Coastal Act)
, including
with consideration for future sea level rise,
by
ensuring that public access and recreational opportunities account for the social, physical, and economic needs of all people.
Policy I
V.D.4:
Public recreational access facilities (e.g., public parks, restroom facilities, parking, bicycle facilities, trails, and paths) shall be sited
and
designed in such a way as to limit potential impacts to coastal resources over the structure's lifetime.
As appropriate, such development may be allowed within the immediate shoreline area only if it
is sited in an area that avoids current and future haza rds,
will not require new or expanded
shoreline protective devices, and will not cause or accelerate beach erosion.
Public
recreational
access
Sea Level Rise
Policies
City of Manhattan Beach
Local Coastal Program Update
15 facilities
shall be sited and designed to
be adaptable and/or non
-
permanent, in anticipation of
potential
loss due to coastal hazards and sea level rise
.
E.
DECISION
-
MAKING, COORDINATION, AND PARTICIPATION
The Decision
-
making, Coordination, and Participation
policies relate to decision making, coordination, and participation in planning for
sea level rise, which are identified by the CCC as key principles for addressing sea level rise in the coastal zone.
Policy IV.E.1:
Use the best available science to determine locally relevant and context -
specific sea level rise projections
for all stages
of planning, design, and reviews.
Policy IV.E.2:
Coordinate planning and regulatory decision making with other appropriate local, State, and federal agencies.
Policy IV.E.3:
Provide for maximum public participation in planning and regulatory processes.
Policy IV.E.4:
Update
the City’s existing Sea Level Rise
Adaptation Plan
as substantive new information is available
, or
as
major updates occur to the State of California Sea Level Rise Guidance .
In addition,
the LCP shall be
updated if warranted by an Adaptation Plan update.
Policy IV.E.5:
Educate the public about the effects of sea level rise and shoreline hazards. Pursue various methods to notify and educate owners, residents, tenants, and potential future
owners of property located in areas
potentially subject to shoreline hazards and the effects of sea level rise. Support legislation to include the risks of sea level rise and shoreline hazards on real estate disclosures included in the sales of property.
Policy IV.E.6:
Create
a Shoreline Monitoring Program, in consultation with other regional, state, and federal agencies
as
well as regional experts
, as detailed in the City’s Sea Level Rise Adaptation Plan.
Monitor, assess, and
inform the public an
d City decision
-
makers about the effects of sea level rise on coastal resources, coastal access, public infrastructure and facilities, and existing development in order to
identify when
Adaptation
Plan triggers have occurred
to
make informed recommendations on adaptation and revise plans and policies as needed
. This includes, but is not limited to, activities such as:
Policy IV.E.6.a:
Tracking the following resources for science updates: Calif ornia Coastal Commission
Sea Level Rise Policy Guidance; OPC Sea Level Rise Guidance; California Climate Change Assessment; U.S. Geological Survey Coastal Change Hazards Program; National Oceanic and Atmospheric Administration Tides and Currents, Santa Mon ica Bay station; and
coordinate with academic institutions to follow scientific reports they produce on sea level rise in Southern California.
Policy IV.E.6.b:
Record coastal flooding and storm damage events and information (photos, videos, reports of eve
nts or damage, date, type, location, and severity of flooding)
where
the
Manhattan Beach Sea Level Rise
Risks,
Hazards,
and
Vulnerability Assessment
(
May
2021
)
found that
flood
ing may
occur, including but not limited to the Ma
rvin Braude
Bike Trail
, buildings along the beach, the lower pier parking lot, the municipal pier,
storm drain outfalls, and the
South Bay Cities’
main sewer trunk line
.
Policy IV.E.6.c.:
Topographic surveys of the beach (e.g., beach elevation transects) to measure beach
width over time.