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ORD 675U ORDINANCE NO. 675U
AN INTERIM URGENCY ORDINANCE OF THE CITY OF
RANCHO PALOS VERDES, CALIFORNIA, EXTENDING
THE MORATORIUM ON THE ACCEPTANCE OR
PROCESSING OF APPLICATIONS, ISSUANCE OF
PERMITS, AND CONSTRUCTION OF ALL STRUCTURES
WITHIN THE PORTUGUESE BEND LANDSLIDE
COMPLEX ADOPTED BY ORDINANCE 674U FOR AN
ADDITIONAL 10 MONTHS AND 15 DAYS, EXPIRING
OCTOBER 2, 2024
WHEREAS, on October 3, 2023, by a four-fifths vote the City Council adopted
Ordinance No. 674U, establishing a temporary 45-day moratorium on the acceptance or
processing of applications, issuance of permits, and construction of all structures within
the Portuguese Bend Landslide Complex, and with this Interim Urgency Ordinance
wishes to extend such a moratorium for an additional 10 months and 15 days, for the
reasons articulated below.
WHEREAS, the City of Rancho Palos Verdes is affected by three large active
Landslide Complexes: the Portuguese Bend Landslide (the PBL), the Abalone Cove
Landslide (the ACL), and the Klondike Canyon Landslide (the KCL), also known as the
Greater Portuguese Bend Landslide Complex, or Landslide Complex. The landslides
have been active since the 1950s to 1970s, and are depicted in Exhibit "A".
WHEREAS, in September 1978, the City Council adopted Urgency Ordinance No.
108U, which established the Landslide Moratorium Area (LMA), which includes the
Landslide Complex. Since 1978, development activity has been circumscribed within the
LMA. in February 1981, the City Council adopted Ordinance No. 139U, which added the
area known as Klondike Canyon to the LMA. The specific restrictions imposed within the
LMA are described in the City's Landslide Moratorium Ordinance, codified as Chapter
15.20 of the Rancho Palos Verdes Municipal Code. The LMA is contiguous with Landslide
Complex depicted in Exhibit "A".
WHEREAS, the LMA is divided into zones 1 through 8. Zones 7 and 8 are owned
by the City and part of the Palos Verdes Nature Preserve. Some of the zones have been
subject to landslides in the past, and were relatively stable until the recent past. Zone 6
has been sliding towards the ocean since the 1950s, some homes having moved as much
as 450 feet from their original location. Zone 6 moves much faster, though not at a
consistent speed throughout, with the most active part of the Zone 6 moving up to 8 feet
a year. The landslide zones are depicted in Exhibit "B".
WHEREAS, development within the LMA is permitted as follows: (i) Properties in
the LMA that are currently developed with residential structures are permitted to make
limited improvements if the City grants a Landslide Moratorium Exception (LME) permit
Monks
§ 15.20.020). (ii) Certain properties within Zone 2 of the LMA (the 16 Mo s
properties and 31 non-Monks properties) may develop their properties if granted a LME
permit (RPVMC § 15.20.040.P). (iii) Construction on properties in the LMA that were not
previously developed with residential structures is not permitted unless a Moratorium
Exclusion (ME) Permit is granted (RPVMC § 15.20.100). (iv) RPVMC Section 15.20.120
provides a mechanism for a property owner to apply to have the moratorium's boundaries
adjusted "to accurately reflect geologic conditions that are present on the property that is
the subject of the application...."
WHEREAS, in the recent past, and especially since May of 2023, the land
movement in the Landslide Complex has increased significantly, most notably in the PBL
and KCL.
WHEREAS, the KCL moved on average by 0.5" per year between 2007 and 2018;
the rate of movement increased between 2018 and 2022 to 1"-2" (and as much as 4");
and in 2022-2023, the rate of movement increased dramatically by up to —30+" in some
places, and more typically by -10-14" in others. See Exhibit "C".
WHEREAS, a report regarding the PBL from McGee Surveying Consulting dated
October 19, 2022 and revised June 6, 2023 concluded "In the last seven months the
movement velocities have accelerated over the average velocity for the previous four
years which saw an acceleration over the previous 15-20 years.... Velocities were stable
prior to 2018. After the Fall of 2018 they increased about 3 to 6 fold at most points and
remained stable to the Fall of 2022. In the last seven months since the Fall of 2022 the
velocities generally have doubled more or less."A further McGee Surveying Report dated
August 6, 2023, concluded, regarding KCL and ACL, that the rate of land movement in
the "2014-2018 period is generally representative of previous years back to 2007. In the
last two months the movement velocities have accelerated over the previous seven-
month period between October 10, 2022 to May 12, 2023. In that seven-month period the
average velocities had accelerated over the previous four-year average which saw an
acceleration over the previous 8 or more years. A monitoring year is 12 months beginning
and ending about the beginning of the rainy season on October 1." The August 6, 2023
report includes a chart with the "measured movements for a sample of monitoring points
for the indicated periods with a projection for the full year of October 10, 2022 to October
2023 based on actual measurements for the period October 10, 2022 to July 15, 2023."
See Exhibit "D" for the October 19, 2022 and August 6, 2023 reports.
WHEREAS, since the adoption of Interim Urgency Ordinance 647U, the City has
received a Preliminary 10/30/23 Draft Survey Report of the Portuguese Bend Oct. 2022-
Oct. 2023-May 2024 Land Movement Monitoring Surveys from McGee Surveying,
further demonstrating the acceleration of the land movement. The report is incomplete,
as it is ultimately intended to span a period of time ending in May 2024, after the current
rainy season. McGee states: "The rate of movement (velocities) of the landslides have
increased over the past five years compared to the previous 12-year average. A notable
increase in the velocities of the landslides were observed between the October 2022
and May 2023, with additional increases in velocities observed between May and July
and again between July and the October 2023 survey. Further, "[t]he table [on page 8 of
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the report] shows a sample of points within the Abalone Cove, Klondike Canyon and
Portuguese Bend Landslides. ... The annual [table shows that the] rate of movement for
the sample averages for each landslide increased 6, 8 and 5 times respectively in the
last 12 months." The report has been added to Exhibit "D".
WHEREAS, McGee Surveying has provided a graphic (PBCA Land Movement
History) that shows the land movement history at several monitoring points within the
PBL, spanning the period of September 2014 through October 10, 2023, which shows
increased land movement starting in 2019, with a sharp increase since 2022 to the
present. The graphic has been added to Exhibit "D".
WHEREAS, recent increased land movement has already caused 2 homes in the
KCL to be "red-tagged" and the building official is closely monitoring several others. The
homes are located at 4332 Dauntless and 4361 Exultant. See Exhibit"E". In July, a dozen
homes in Rolling Hills Estates were destroyed because of land movement, and experts
believe the entire Palos Verdes Peninsula is an area of concern [see
https://www.youtube.cam/watch?v=WA3mwOISKjY]. The landslide in Rolling Hills
Estates was likely caused by the increased rain this past winter or by a broken water
main.
WHEREAS, based on readings at 2 water pump locations in KCL, the water table
has risen quickly and dramatically from December 2022 to today from 91.4' below the
surface to 5.2' at Location 2, and 97.5' to 8.7' at Location 3. See Exhibit "I."
WHEREAS, a draft report from Cotton, Shires and Associates, Inc. "provide[s] a
preliminary geotechnical assessment of recent land movement within the Portuguese
Bend Reserve ... with a specific focus on the impacts of land movement to the Burma
Road Trail." Per the report, "[s]ome areas of the Reserve are now experiencing significant
land movement and ground surface manifestation that is beyond the limits of the
historically active and previously mapped Portuguese Bend Landslide, resulting in
damage to trails and fire roads which provide access for public safety, utilities,
maintenance, conservation, and public recreation."
WHEREAS, the Cotton Shires and Associates, Inc. report cites to the October 19,
2023/June 6, 2023 McGee Survey Consulting report ("Velocities were stable prior to
2018. After the Fall of 2018 they increased about 3 to 6 fold at most points and remained
stable to the Fall of 2022. In the last seven months since the Fall of 2022 the velocities
generally have doubled more or less.") and states: "[t]his is a significant and important
observation from the surveyor and comports with the past several years of field
observations by CSA staff of roadway distress and trail distress, within the PBR, as well
as reports of street distress, building distress and utility line breaks throughout the various
known landslide areas. We have prepared several graphics based upon our own analysis
of the GPS survey monitoring data to further illustrate what is happening with the landslide
ground movement. Figure 2 (attached) depicts horizontal displacements (in feet) and
ground displacement vectors, for 12 selected GPS survey monuments mostly located in
the mid and upper Ancient Portuguese Bend Landslide Complex. These figures are based
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upon McGee's GPS monitoring of the survey monuments from October 2018 to May 2023
(with the exception of two monuments which were last read in October 2022, PB18 and
AB71). Four of these monuments were also read in mid-July, 2023 and those movement
data are also presented. Two of the monuments, CR07 and FT06 are located on Burma
Road outside of the Portuguese Bend Landslide and indicate 1.67 feet and 3.09 feet of
horizontal displacement over the -4.5- year period. The CR07 point moved an additional
0.42 feet in two months (through July 15, 2023), which translates to ground movement
velocity of about 2.5 feet per year. Most of the other points on this figure are in the Ancient
Portuguese Bend Landslide Complex (and mostly in LMA Zone 2) and are indicating total
displacements of approximately 1 to 3 feet (or average velocities of about 0.22 to 0.67
feet/year across the -4.5-year period). Several of these points in LMA Zone 2 that were
also monitored in July, 2023 showed continued acceleration from May to July 2023, with
calculated velocities of -1.25 feet/year at AB67 to -3.9 feet/year at AB53. These are
extraordinary rates of landslide movement that, to our knowledge, have not been
previously documented in the LMA Zone 2 area." (Underlining added.)
WHEREAS, the Cotton Shires and Associates, Inc. report concludes, "Landslide
movements throughout the Ancient Portuguese Bend Landslide Complex outside of the
historical boundary of the Portuguese Bend Landslide previously exhibited relatively low
rates of creep movement in the 11-year monitoring period of 2007-2018 for which we
have readily available data. Beginning in late 2018, and through the present, the survey
data indicate a significant acceleration of landslide movement. The movement of the
Portuguese Bend Landslide also accelerated in this timeframe. The cumulative
displacements over this time have now manifested as headward enlargement of the
Portuguese Bend Landslide as well as new active landslide masses forming northwest of III
the Portuguese Bend Landslide crown in Landslide Moratorium Area Zone 1, upslope
from LMA Zone 2." The draft report is attached as Exhibit "F".
WHEREAS, due to increased land movement, the Landslide Complex has seen
an increase in water main breaks. Starting in 2016, the following water main breaks
occurred and had to be fixed urgently by CalWater. The exact location varies, as the break
may have occurred along different sections of the pipe, but broken down by trail name,
the breaks occurred on the following dates:
• Gary's Gulch Trail: August 29, 2023.
• Vanderlip Trail: October 2020; November 25, 2021; April 24, 2023; April 25,
2023; June 14, 2023; September 16, 2023 (see photos, Exhibit "G").
• Burma Road Trail: July 2016; October 2021; March 2022; November 2022
(two separate breaks); February 2023; March 2023; August 16, 2023 (see
photos, Exhibit "G"); August 18 and 21, 2023 (see photos, Exhibit "G");
September 5, 2023; September 28, 2023 (see photos, Exhibit "G").
• Conqueror Trail: June 2018; May 20, 2023; August 16, 2023.
• Barn Owl Trail: September 5, 2023.
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WHEREAS, on September 29, 2023, the City closed the intersection of Dauntless
and Exultant for the foreseeable future due to recent landslide-related subsidence.
Additionally, effective September 29, 2023, Cal Water will have 24/7 personnel on site in
the Seaview neighborhood of the KCL to respond immediately to any broken water main
lines. Lomita Station deputies have increased their patrol of the neighborhood particularly
in the area of the red-tagged homes.
WHEREAS, the City has established, via repeated geologic studies, that a
significant factor in the speed of land movement in the Districts is the amount of water in
the soil. ACLAD, for example, has installed a number of dewatering wells within its
boundaries to mitigate the land movement.
WHEREAS, the 2022-2023 rainy season brought exceptional amounts of rain to
the region. The 2022-2023 rainy season dumped over 200 percent of the average annual
rainfall in the region [source:
http://www.ladpw.org/wrd/precip/alert rain/season_raindata.cfm?id=2570300] with the
region experiencing about 26 inches of rain including 3.4 inches from Tropical Storm
Hilary on August 20-21, 2023. As a result of the increased amount of rain, all the Landslide
Complexes in all the Districts have been subject to an alarming increase in land
movement. Additionally, there is a strong likelihood that El Nino will bring another wet
winter in 2023-2024, [see https://ktla.com/weather/historically-strong-el-nino-possible-
what-it-means-for-winter/; https://patch.comicalifornia/palosverdes/wet-el-nio-ahead-
11 term=article-slot-
1&utm source=newsletter-
daily&utm medium=email&utm campaign=newsletter&user email=10970c30f10d3992
86140af9d05d399c34c897422c415a4087d6e 1"cfd 9df l c29;https://wwvv.kget.com/weathe
r/weather-head lines/noaa-releases-2023-2024-winter-
predictions/?utm campaign=socialflow&utm medium=referral&utm source=facebook.c
om&mibextid=Zxz2cZ ], which, if it brings the anticipated rainfall, will exacerbate the
landslide.
WHEREAS, in response to an increase in public inquiries and concerns regarding
the water main breaks, damage to homes, and accelerating land movement raised at the
September 19, 2013 City Council meeting, the City has created a dedicated homepage
on the City's website to the landslide, as well as an email address
(landmovementrpvca.gov). City Staff is forming a Working Group, to meet on a weekly
basis or as needed, that will have the following representatives:
• City of Rancho Palos Verdes: Ara Mihranian, City Manager; Ramzi Awwad,
Director of Public Works.
• Other stakeholders: Seaview HOA; Portuguese Bend Beach Club HOA;
Klondike Canyon Landslide Hazard Abatement District Board; Abalone
Cove Landslide Hazard Abatement District Board; Portuguese Bend HOA;
Cal Water; So Cal Gas; Southern California Edison; Los Angeles County
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Public Works Sanitary Sewer Maintenance and Operations; Los Angeles
County Sanitation District.
The meetings' purposes were:
• Prevent utility leaks from exacerbating landslide movement
• Prevent utility damage from impacting the natural and built environment
• Formulate and implement solutions to landslide movement
• Coordinate among all stakeholders
• Provide regular updates to the public
WHEREAS, the City has been receiving a growing number of comments
expressing concern regarding the accelerating land movements, from homeowners in the
Landslide Complex, and from other concerned citizens.
WHEREAS, Government Code Section 65858 expressly authorizes the City
Council to adopt an Interim Urgency Ordinance for the immediate preservation of the
public peace, health, or safety, if the ordinance is approved by four-fifths of the City
Council.
WHEREAS, in 2005, the City Council of the City of Rancho Palos Verdes adopted
Interim Urgency Ordinance No. 427U, which halted construction and the issuance of
permits on a portion of the Klondike Canyon Landslide, based on increased movement
following an unusually wet winter. The moratorium was extended by Interim Urgency
Ordinance Nos. 439U, and repealed by Ordinance No. 469U, and its non-urgency
version, Ordinance No. 526. The City Council adopted amendments to Chapter 15.20 at
that time.
WHEREAS, Section 65858(f) provides that "...upon termination of a prior interim
ordinance, the legislative body may adopt another interim ordinance pursuant to this
section provided that the new interim ordinance is adopted to protect the public safety,
health, and welfare from an event, occurrence, or set of circumstances different from the
event, occurrence, or set of circumstances that led to the adoption of the prior interim
ordinance."
WHEREAS, the City Council finds that the increase in land movement activity in
the Landslide Complex is of great concern to the residents within the Districts, to the City,
and to the Palos Verdes Peninsula as a whole, and presents an imminent threat to the
public health and safety. The City Council further finds that the circumstances today are
different from the circumstances that prompted the 2005 moratorium. Here, the increased
precipitation has contributed to increased movement in all of the Landslide Complex.
Therefore, is broader in scope and encompasses all of the City's Landslide Complex.
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WHEREAS, land movement has increased even more during the week of
September 25,2023, particularly in the Seaview neighborhood of the KCL; Cal Water has
agreed to have a representative present in the area at all times to address water main
breaks immediately. Additionally, it has come to the City's attention that a number of
residents have pools that are leaking water into the ground, likely due to cracking because
of earth movement. The City Manager has made a request of the Klondike Canyon,
Portuguese Bend, and Seaview communities to cease watering and to not refill swimming
pools that are losing water. See Exhibit "H".
WHEREAS, the City Council finds that pending mitigation and stabilization of the
land movement, as further articulated under Section 5, below:
(1) The approval of the development of housing development projects, as defined
in Section 65905.5 of the Government Code would have a specific, adverse impact upon
the public health or safety. As used in this paragraph, a "specific, adverse impact" means
a significant, quantifiable, direct, and unavoidable impact, based on objective, identified
written public health or safety standards, policies, or conditions as they existed on the
date that the ordinance is adopted by the legislative body.
(2) The interim ordinance is necessary to mitigate or avoid the specific, adverse
impact identified pursuant to paragraph (1).
(3) There is no feasible alternative to satisfactorily mitigate or avoid the specific,
adverse impact identified pursuant to paragraph (1) as well or better, with a less
burdensome or restrictive effect, than the adoption of the proposed interim ordinance.
WHEREAS, Section 66300(b)(1) of the Government Code provides that "with
respect to land where housing is an allowable use, ... an affected city shall not enact a
development policy, standard, or condition that would have [the effect of...i]mposing a
moratorium or similar restriction or limitation on housing development, including mixed-
use development, within all or a portion of the jurisdiction of the affected ... city, other
than to specifically protect against an imminent threat to the health and safety of persons
residing in, or within the immediate vicinity of, the area subject to the moratorium...." The
statute further provides that the City may not enforce such a moratorium on housing until
the ordinance has been submitted to, and the City has received approval from, the
Department of Housing and Community Development (HCD).
WHEREAS, on November 6, 2023, HCD approved the moratorium on construction
within the Greater Portuguese Bend Landslide Complex for the entirety of the 24 months
allowed by Government Code 65858, were the City to extend it for that period of time. In
a letter to Brandy Forbes, Director of the City's Community Development Department,
HCD acknowledged "the severity of the Portuguese Bend Landslide Complex's condition
and the potential harm to public health and safety, and the environment, and anticipates
that [the moratorium] will need to be extended beyond the 45-day period, pursuant to
Government Code section 65858. HCD hereby approves the adoption and enforcement
of Interim Urgency Ordinance No. 674U during the effective period of 45 days from its
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adoption and its planned extension for up to 22 months and 15 days by the City of Rancho
Palos Verdes." HCD's November 6, 2023 letter is attached as Exhibit "J".
WHEREAS, pursuant to the provisions of the California Environmental Quality Act,
Public Resources Code Sections 2100 et. seq. ("CEQA"), the State's CEQA Guidelines,
California Code of Regulations, Title 14, §15000 et. seq., the City's Local CEQA
Guidelines, and Government Code §65962.5(f) (Hazardous Waste and Substances
Statement), it has been determined that the adoption of the Urgency Ordinance to impose
a moratorium on the acceptance or processing of applications, issuance of permits, and
construction in the Districts is exempt from CEQA, pursuant to Section 15061(b)(3). This
Interim Urgency Ordinance is exempt because it proposes to impose a moratorium all
construction on properties within the Districts and it can be seen with certainty that there
is no possibility that the activity in question may have a significant effect on the
environment.
WHEREAS, this Interim Urgency Ordinance is proposed to allow the City to
continue to address and mitigate an imminent threat to public health and safety and
therefore is exempt from CEQA pursuant to Public Resources Code, Section
21080(b)(4) and CEQA Guidelines, Section 15269.
WHEREAS, this Interim Urgency Ordinance is proposed to allow the City to
continue to protect the environment by preventing the exacerbation to existing unstable
geologic conditions caused by activities related to new construction and therefore is
categorically exempt from CEQA pursuant to CEQA Guidelines, Section 15308 and none
of the exceptions to this exemption set forth in CEQA Guidelines, Section 15300.2 apply
to this Interim Urgency Ordinance.
WHEREAS, on November 7, 2023, the City issued a report outlining the measures
the City is taking to address the conditions that gave rise to this moratorium, as required
by Section 65858 of the Government Code.
WHEREAS, all legal prerequisites to the adoption of the Interim Urgency
Ordinance have occurred.
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF RANCHO PALOS
VERDES, CALIFORNIA, DOES ORDAIN AS FOLLOWS:
SECTION 1. Moratorium
Subject to the exceptions articulated in Section 2 below, during the effective period
of this Ordinance, no application for permit will be accepted, no consideration of any
application for any permit will be made, and no permit will be issued by the City for any
construction on any property within the Landslide Complex until this Ordinance has
expired or has been repealed according to applicable law. This Moratorium also applies
to any pending applications, and any permits or entitlements that have issued and
construction not commenced.
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"Permit" means any City planning land use approvals, and any building, grading,
plumbing, electrical, or mechanical permit, whether the approval or issuance is
discretionary or ministerial.
SECTION 2. Exceptions
The Moratorium shall not apply to the following:
A. Construction necessary for repair or maintenance of existing structures, roadways,
and any infrastructure such as water lines, sewer lines, electrical or traffic installations,
etc.
B. Construction necessary for the implementation, establishment, repair, or
maintenance of any landslide mitigation measures.
C. Construction necessary for the immediate preservation of the public health and
safety.
D. Construction that the City Manager deems necessary and consistent with the
purposes of this interim urgency ordinance. Any such exception shall require written
findings by the City Manager, and must be ratified by the City Council at the regular
meeting following the City Manager's determination.
111 SECTION 3. Urgency Findings; Specific Adverse Impact Findings
A. The City Council finds that there is a current and immediate threat to public
safety, health, and welfare posed by the increased land movement within the Landslide
Complex, and further finds that the land movement outside the delineated Landslide
Complex/LMA are of grave and immediate concern. Additionally, formerly stable portions
of the Landslide Complex are now moving at a faster clip, which has accelerated since
2018, but has increased dramatically since the last rainy season. Existing homes and
structures are being threatened by the,land movement, and may be facing a greater threat
still if the coming winter brings the promised strong El Nino, with the concomitant amounts
of rainfall.
B. The City Council finds that construction of new structures and buildings in
the Landslide Complex constitutes a specific adverse impact that cannot satisfactorily be
mitigated at this time by the adoption of a less restrictive regulation than this interim
ordinance: the additional load provided by new buildings, including the required grading,
will further destabilize the Landslide Complex, thus increasing the land movement speed
and damage to existing structures. Additional construction will also require water and
sewer infrastructure, which may leak into the soil and further exacerbate the land
movement; in light of the increase in water main breaks, this is a very real and immediate
concern. It is imperative at this time that no additional load and water/sewer utilities be
placed on the Landslide Complex, while the City works to further study and stabilize the
area, and the boundaries of the Landslide Complex may have to be revised and likely
expanded. At this time a less restrictive regulation is not feasible as all of the City's
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Page 9 of 14
resources must be focused on implementing the City's Landslide Remediation Project
(see below), and it cannot be known which additional project or water main break may
cause a catastrophic failure of any part of the Landslide Complex.
C. Additionally, the City Council finds that allowing construction in an actively
moving landslide will not further the statewide policy of increasing housing stock or
meeting the City's RHNA, and instead will endanger the existing housing and the area's
residents.
D. The City Council therefore finds that in order to protect the health and
safety of the residents of the Landslide Complex, the City,, and the Palos Verdes
Peninsula, it is necessary to adopt this Interim Urgency Ordinance.
SECTION 4. Authority and Effect
A. The State Planning and Zoning Law, Government Code Section 65000 et
seq., broadly empowers the City to plan for and regulate the use of land in order to provide
for orderly development, the public safety, health, and welfare, and a balancing of
property rights and the desires of the community and how its citizens envisions their city.
B. Government Code Section 65858 expressly authorizes the City, in order to
protect public safety, health, and welfare, to adopt an Interim Urgency Ordinance
prohibiting a use that is in conflict with a contemplated general plan, specific plan, or
zoning proposal that the legislative body, planning commission, or the planning
department is considering or studying or intends to study within a reasonable time,
provided that the urgency measure shall require a four-fifths vote of the legislative body
for adoption, and shall be of no further force and effect 45 days from its date of adoption,
unless duly extended for an additional 10 months and 15 days. The Interim Urgency
Ordinance may be extended for a further 12 months.
SECTION 5. Review and Study
A. The City is seeking the services of a firm to study and make
recommendations for the,entirety of the Landslide Complex. As land movement appears
to be occurring outside of the understood boundaries of the current Landslide Complex,
the study will include recommendations regarding whether and to what extent the
boundaries of each landslide and of the Landslide Complex as a whole should be revised.
B. The City is in the process of implementing a Landslide Remediation Project
for the PBL. The Project's purpose is, just as its name suggests, a large-scale,
sophisticated project that would seek to stabilize the PBL, largely by the installation and
operation of a network of powerful hydraugers. (See City Council staff reports related to
the Landslide Remediation Project dated December 17, 2019, December 19, 2020,
August 15, 2023, September 19, 2023) The project will be in three phases:
Phase I - Repair of the Existing Fractures
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Surface fractures (also known as fissures) in the Portuguese Bend area are the
result of land movement. These existing fractures are a few feet wide and some are as
deep as 150 feet. The fractures intercept stormwater runoff where this water discharges
into the ground. The proposed mitigation improvements include filling these fractures with
slurry material that is easily placed in them. The slurry consists of 95-97% fly ash and 3-
5% cement. Fly ash is a fine powder that is a byproduct of burning pulverized coal in
electric power-generating plants. It is inert and its use has been proven to be very safe in
these applications. This phase of the project is intended to eliminate storm runoff from
easily becoming part of the groundwater and is an important component in efforts to
minimize landslide-related ground movement.
Phase II - Surface Drainage Improvements
The surface drainage improvements include the refurbishment of existing swales
and pipes, and construction of a reduction flow area, which essentially serves as a
detention basin near the bottom of the hill landward of Palos Verdes Drive South (PVDS).
In summary, over the years, the existing swales have eroded and the drainage pipes have
clogged, resulting in inadequate performance. In some areas, sections of the drainage
pipes have been disconnected, displaced or are missing. Further, as a direct result of
landslide movement and land displacement, a few low areas have formed. During rainfall
events, stormwater runoff is trapped in these areas. Since there is no outlet, the collected
stormwater runoff creates ponds and eventually, the water percolates into the ground and
exasperates the landslide.
The project will no longer result in stormwater ponding because runoff will be
conveyed through newly establish/refurbished pipes and swales to the ocean in a
controlled manner.
Phase III - Below-Grade Hydraugers
Hydraugers, to be constructed below grade, are designed to alleviate artesian
water pressure underground in the Portuguese Bend Landslide area. Their function is
similar to vertical dewatering wells, but they are installed horizontally, beneath the active
movement zone of the landslide. The City's consultant believes that vertical dewatering
wells are not sustainable in this area because of the land movement. The landslide is
active, with annual movement measured in feet, and consequently, vertical dewatering
wells shear quickly due to the land movement. Until this land movement is minimized,
vertical wells will continue to shear. The high rate of land movement in Portuguese Bend
has resulted in the rapid failure of vertical wells in the areas that will be targeted with
hydraugers. This third phase of construction therefore involves the installation of the
hydraugers which will follow the installation of surface drainage features.
The Project is anticipated to cost $33 million. The City has sought and obtained a
grant in the amount of $23.3 million from the Federal Emergency Management Agency.
111 The City is currently seeking the remainder of the funding from state and local sources,
and anticipates being able to raise sufficient funds within the next 12 months in order to
begin construction of the project.
01203 0023/935568 1
Ordinance No. 675U
Page 11 of 14
The status of the project and anticipated timeline is as follows: Award professional
services contracts for final engineering: on September 19, 2023 the City Council
appropriated $925,289 for additional engineering services, making the total financial III
commitment so far $2,295,056. Staff anticipates 90% plan completion and certification of
the EIR in September of 2024, and complete final engineering and permitting by
September 2025.
SECTION 6. Consistency with the General Plan
The City Council finds that this Ordinance is consistent with the following goals
and policies of the City's General Plan.
Circulation Element Policies — GP Page C-7
30. Discourage the installation or extension of any infrastructure component
into any area known to be hazardous unless appropriate liability safeguards (such as
geological hazard abatement districts) are in place and adequate mitigation measures
are incorporated into the design.
31. Allow new development only where adequate infrastructure systems can
reasonably be provided.
Conservation and Open Space Element Policies — GP Page COS-4
3. Require any development within the Resource Management Districts of
high slopes (RM 3) and dormant landslide area (RM 5) to perform at least one, and
preferably two, independent engineering studies concerning the geotechnical, soils, and
other stability factors (including seismic considerations) affecting this site following
established geological industry standards.
6. Prohibit activities that create excessive silt, pollutant runoff, increase
canyon-wall erosion, or potential for landslide within Resource Management Districts
containing hydrologic factors (RM 6).
10. Stringently regulate irrigation, natural drainage, and other water-related
considerations in new developments and existing uses affecting existing or potential slide
areas.
11. Consider development exceptions in areas otherwise precluding
development for health and safety reasons, only if the development can establish that it
can overcome the conditions otherwise precluding development, and is otherwise
compatible with the intent of the General Plan and the Specific Plan for the area.
Safety Element Goals — Page S-6
1. Provide for the protection of life and property from both natural and human-
made hazards within the community. 111
01203 0023/9355681
Ordinance No. 675U
Page 12 of 14
4. Protect life and property and reduce adverse economic, environmental, and
social impacts resulting from any geologic activity.
Social Services Element Policy— Page SS-3
9. Prioritize enforcement activities of residential structures with known health
hazards.
SECTION 7. Severability
The City Council-hereby declares, if any provision, section, subsection, paragraph,
sentence, phrase or word of this ordinance is rendered or declared invalid or
unconstitutional by any final action in a court of competent jurisdiction or by reason of any
preemptive legislation, then the City Council would have independently adopted the
remaining provisions, sections, subsections, paragraphs, sentences, phrases or words of
this ordinance and as such they shall remain in full force and effect.
SECTION 8. Publication
The City Clerk shall certify as to the passage and adoption of this Interim Urgency
Ordinance and shall cause the same to be published in a manner prescribed by law.
SECTION 9. Effectiveness of Ordinance
This Ordinance shall take effect immediately upon adoption by a four-fifths vote of
the City Council, pursuant to the authority conferred upon the City Council by Government
Code § 36937. This Ordinance shall be of no further force and effect 10 months and 15
days following the date of its adoption unless extended in accordance with the provisions
set forth in Government Code § 65858. Not later than 10 days prior to the expiration of
this urgency ordinance, the City Council shall issue a written report as required by
applicable state law.
PASSED, APPROVED and ADOPTED this 14th day of November, 2023, by a four-
fifths vote of the entire City Council.
kj
Join i ikshank, Mayor Pro Tem
ATTEST:
./41„ 4444..4/1.,,
.eres(akaoka, City Clerk
STATE OF CALIFORNIA )
111 COUNTY OF LOS ANGELES ) ss
CITY OF RANCHO PALOS VERDES )
01203.0023/935568 1
Ordinance No. 675U
Page 13 of 14
I, Teresa Takaoka, City Clerk of the City of Rancho Palos Verdes, do hereby certify
that the whole numbers of the City Council of said City is five; that the foregoing Ordinance
No. 675U was duly and regularly adopted by the City Council of said City at a regular
meeting thereof held on November 14, 2023 by the following vote:
AYES: Alegria, Bradley, Seo and Mayor Pro Tem Cr,uikshank
NOES: None
ABSENT: Ferraro
ABSTAINED:None
y �
01203 0023/9355681
Ordinance No. 675U
Page 14 of 14
Ordinance No. 675U
Exhibit A
Page 1 of 2
Ordinance No. 675U
Exhibit A
Page 2 of 2
Ord. 675U
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Ord. 675U
Exhibit B
Page 2 of 2
Ord. 675U
Exhibit C
Page 1 of 2
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Ord. 675U
Exhibit C
Page 2 of 2
Ord. 675U
Exhibit D
Page 1 of 26
Ord. 675U
Exhibit D
Page 2 of 26
Survey Report
of the
Portuguese Bend Sept. 2021-Oct. 2022-May 2023
Land Movement Monitoring Surveys
for the
City of Rancho Palos Verdes
prepared by
McGee Surveying Consulting
Date: October 19, 2022 Revised June 6, 2023
The Portuguese Bend Landslide is monitored on a tri-annual basis beginning with the initial survey of all
current monitoring points at the beginning of the rainy season in the Fall of each year followed by two
subsequent partial monitoring surveys in the winter and spring. The following is a summary of the Initial Fall
2022 Monitoring Survey followed by addendums for the winter and spring Partial Monitoring Surveys. The
movement results are listed as follows: for the Initial Fall Survey for the period of September 2021 to October
2022, the Winter Partial Survey for October 2022 to March 2023, and for the Spring Partial Survey for March
2023 to May 2023 and October 2022 to May 2023. The movements for these periods are listed on Pages 4 & 6.
Initial (Fall) Survey - October 10, 2022 Full Monitoring Survey No. 34
Second (Winter) Survey - March 13, 2023 Partial Monitoring Survey No. 35
Third (Spring) Survey - May 12, 2023 Partial Monitoring Survey No. 36
ATTACHMENT: “PB MOVEMENT DATA POSTING 2007-2022.10.xlsx”
OVERVIEW:
McGee Surveying Consulting (MSC) performed the Fall 2022 land movement monitoring survey of the
Portuguese Bend Landslides. The survey was planned, coordinated, and executed by Michael McGee, PLS3945
of MSC who is responsible for the field surveys, processing observations, network adjustments, analysis, and
reports. This survey determined the precise positions of 67 monitoring points to assess their annual and overall
movements. Subsequent Addendum Partial Surveys in the Winter and Spring assessed the movements between
October 2022 and May 2023. See the previous 2021-2022 Report published in May 2022 for more survey details
and procedures utilized in this survey but not re-stated here. The annual Fall 2021 to 2022 movements and 2022
coordinates are listed in the attached spreadsheet titled “PB MOVEMENT DATA POSTING 2007-
2022.10.xlsx”. A substantial increase in movement velocities was observed between the October 2022 and May
2023 compared to the previous four year average. See the “Partial Assessment of Observations” on Page 8.
The horizontal and vertical positions of the monitoring points are based on the North American Datum of 1983
(NAD83) Epoch 2007.00 and the North American Vertical Datum of 1988 (NAVD 88) reference frames. The
NGS Geoid03 is used to model orthometric heights (elevations) based on measured ellipsoid heights as
explained in said May 2021-2022 Report. The latitudes and longitudes determined by GNSS measurements are
projected into NAD83 California State Plane Coordinates Zone 5 in US Survey Feet.
Given the proven stability, since 2007, of Point AB02 (at the south end of Portuguese Point) relative to PVE3
(CGPS Station at City Hall), the method for recovering the reference frame was modified in 2019 to improve the
efficiency and simplify the processing and analysis of the surveys. The previous procedures were modified by
fixing point AB02, instead of PVE3 and checking to PVE3RP (control point on the concrete base of PVE3).
Point AB61 (on Portuguese Point) provides redundant verification that the reference frame is stable and
successfully recovered. Beginning in the fall of 2019, the network adjustments were constrained to the 2018
NAD83 position and NAVD88 height of AB02 checking to PVE3RP and AB61. The positions are listed below.
Pt# Latitude Longitude NAVD88 Ht Source)
AB02 33-44-13.84878 118-22-26.19243 116.47 ft Oct. 2018 position
PVE3RP 33-44-35.74239 118-24-15.27451 346.88 ft Average of 5 years
AB61 33-44-18.5730 118-22-25.9580 140.43 ft Average since 2007
Ord. 675U
Exhibit D
Page 3 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 2 of 7
The Fall 2022 Survey is the 34th Monitoring Survey. For data management purposes the point names are prefixed
with a sequential number to distinguish between surveys. For example, on the 16th monitoring survey AB61 was
named M16AB61 where M16 indicates the sequence number since the initial M01 Monitoring Survey in
September 2007. The prefix is stripped in the attached “PB MOVEMENT DATA POSTING” document.
AB61 and AB20 previously served as suitable GNSS Base Stations. Presently AB73 is utilized as a Base
Station. AB73 is located on the US Pony Club property and exclusive permission for MSC to enter the property
is confirmed prior to each survey with the understanding that strict limited driving protocols will be observed.
Access was obtained unilaterally by MSC from the manager of the Pony Club and does not extend to others.
Point AB73 is not a planned monitoring point, is not necessary and not to be include in surveys by others.
Prior to 2019, geodetic grade GNSS receivers collected static satellite signal data for post processing. Presently,
a Leica GS18 Base with a GS18T RTK Rover operating in real-time with an FM radio system is used to
measure the monitoring points. This system is the latest technology and delivers increased productivity and
greater precision of point positions in real time. The GS18 receiver incorporates an Inertial Measurement Unit
and tracks four Global Navigation Satellite Systems (GNSS) including GPS, GLONASS, Galileo and Beidue
Satellites. The differences in two measured vectors are acceptable if they fall within 0.03 feet (1 cm)
horizontally; otherwise, additional measurements are obtained. Experience has shown the independent
measurements agree generally 0.01 to 0.02 feet.
M34 MONITORING NETWORK
Ord. 675U
Exhibit D
Page 4 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 3 of 7
GNSS Survey Parameters and Metadata
Date of Initial Annual Survey: M34 – October 10, 2022 (mean date) between 0800-1700 PDST (+7 hrs for UTC).
Constellations: GPS (31 Satellites), Russian GLONASS (23 Satellites), Galileo (23 Satellites) and Beidue (40 Satellites).
Observables: L1 & L2 Carrier Waves on GPS, GLONASS and Beidue; and four Carrier Waves on Galileo Satellites
Data Epoch Rate - 0.2 seconds (20HZ) at the GS18 RTK Rover; 1 second RTK at the GS18 Base
Satellites: 20-40; GDOP: < 2; Elevation Mask: 0° at the Rover and Base Station
Ephemeris: Broadcast for RTK vectors.
Weather: Mostly calm clear skies, temperature 65-75° F, no significant weather.
Space Weather: Boulder K Index 2-4 averaging 3 (gauges ionospheric activity on a scale of 0-9; less than 6 preferred)
Equipment: GNSS Base Receiver Unit No.: M11, Operator: M. McGee, PLS; Occupied Base Station
Make & Model: Leica GS18 with integrated Antenna; Mount: Tribrach on Tripod
GNSS Rover Receiver Unit No.: M10, Operator: M. McGee, PLS
Make & Model: Leica GS18T with integrated Antenna; Mount: Fixed Height Pole #4
Processing & Adjustments: Leica Infinity v4.0 and "Starnet-PRO” version 11.0.6 Software
ADJUSTMENTS & ANALYSIS
Network Adjustment: A minimally constrained adjustment was computed to develop NAD83 (2007) 2007.00
Epoch Zone 5 State Plane Coordinates and NAVD88 Heights of the monitoring points by fixing Point AB02 as
noted previously. The NAVD88 orthometric heights (elevations) were determined by combining the measured
ellipsoid heights with the Geoid03 Model. AB02 is unaffected by the land movement and the stability was
verified relative to PVE3RP which is outside the influence of the land movements. Listed here are the
differences from the stable position of AB02 to the measured positions of other stable points.
Differences in Feet
ID dN dE dZ_
AB02 0.000 0.000 0.000 Fixed
AB61 -0.003 -0.006 0.016 Stable Check Point on Portuguese Point
PVE3RP -0.002 -0.015 0.000 Stable Check Point at City Hall
Comments: Fixing AB02 finds no horizontal differences at PVE3RP or AB61 other than insignificant random
measurement noise. Given that AB02, PVE3RP, and AB61 are in good relative agreement, the survey reference
frame is deemed stable and successfully recovered from which accurate local land movements are determined.
ACCURACY STATEMENTS
Vector Residuals: The two-dimensional vector residuals average 0.007 feet and the absolute value of the
vertical residuals average 0.009 feet as listed below. The vector residuals are based on a network adjustment of
independent point positions.
Vector Lengths(ft) Two Dimensional Residuals Absolute Vertical Residuals
Vary Average Average Std.Dev. Maximum Average Std.Dev. _ Range
419-9657 3218 0.007 0.004 0.016 0.009 0.007 -0.05 to +0.04
Movement Accuracy: A point is deemed to have moved if, at the 95% level of confidence the horizontal
movement (signal) of a point between two epochs is greater than the 95% Error (noise). Based on multiple
independent occupations, the horizontal (2D) movements reported between September 2021 (M31) and October
2022 (M34) statistically attained a relative average accuracy of 0.022 feet at the 95% Level of Confidence with
a Standard Deviation of 0.003 feet and a Range of 0.013 to 0.031 feet. See the attached file “PB MOVEMENT
DATA POSTING 2007-2022.10.xlsx” for movements and errors estimates.
Ord. 675U
Exhibit D
Page 5 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 4 of 7
Table of Annual Movements of Monitoring Points
2D Horizontal and Vertical Movements in Feet
September 28, 2021 (M31) to October 10, 2022 (M34) = 12.4 Months
Listed below are the two-dimensional horizontal movements and vertical (elevation) changes during the period.
See the attached spreadsheet “PB MOVEMENT DATA POSTING 2007-2022.10.xlsx”. Note: The horizontal
measurement confidence is estimated at +/-0.02’ (1/4”); therefore, movements of 0.02’ or less are deemed
statistically to not have moved. The estimated vertical measurement confidence is +/-0.05’.
Point ID Horizontal
Movements
Vertical
Changes
Point ID Horizontal
Movements
Vertical
Changes
AB01 0.02 -0.07 KC02 0.21 -0.03
AB02 0.00 0.00 KC05 0.09 -0.02
AB04 0.90 -0.12 KC06 0.16 -0.06
AB05 0.62 -0.11 KC07 0.02 0.01
AB13 0.49 -0.24 KC13 0.09 0.00
AB16 0.15 -0.05 KC14 0.00 0.01
AB17 0.02 -0.05 KC15 0.16 -0.03
AB20 0.51 0.00 KC16 0.02 -0.01
AB24 0.43 -0.01 KC17 0.14 -0.04
AB50 0.34 0.02 KC18 0.40 -0.02
AB51 0.31 -0.10 PB04 0.80 -0.15
AB53 0.49 -0.01 PB06 0.66 -0.06
AB57 0.44 -0.14 PB07 0.72 -0.24
AB58 0.41 -0.03 PB08 0.66 0.05
AB59 0.55 -0.15 PB09 0.65 -0.04
AB60 0.45 -0.06 PB12 0.94 -0.15
AB61 0.01 0.02 PB13 0.70 -0.02
AB62 0.78 -0.09 PB18 0.60 -0.20
AB63 0.72 -0.19 PB20 0.85 -0.14
AB64 0.06 -0.03 PB21 0.71 -0.13
AB65 0.26 -0.11 PB26 0.62 -0.01
AB66 0.38 -0.07 PB27 0.82 -0.17
AB67 0.18 -0.05 PB29 0.72 -0.15
AB68 0.32 -0.11 PB54 0.59 0.04
AB70 0.48 -0.03 PB55 0.80 -0.04
AB71 0.32 -0.08 PB59 1.02 -0.24
AB73 0.45 -0.05 PB67 1.43 -0.21
CR07 0.31 -0.27 PB68 0.75 -0.12
CR50 0.02 -0.02 PB69 0.86 -0.14
CR51 0.02 -0.04 PB70 0.72 -0.34
CR53 0.02 -0.03 PB71 0.62 -0.15
FT06 0.58 -0.28 UB02 0.78 0.04
FT08 0.03 -0.02 PVE3RP 0.02 0.00
FT09 0.01 0.01
Ord. 675U
Exhibit D
Page 6 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 5 of 7
Addendum No. 1
Monitoring Survey No. M35 Report
Portuguese Bend Landslide Monitoring
March 13, 2023 Partial Monitoring Survey
Addendum No. 1: Report on the second of three annual Portuguese Bend Monitoring Surveys (M35). The
average date of the field survey is March 13th. This partial survey included 43 points (30 required) which are a
sub-set of the monitoring network. A minimally constrained adjustment was processed to develop NAD83
(2007) Epoch 2007.00 CA State Plane Coordinates and NAVD88 Heights. The estimated vector horizontal (2D)
residuals at unobstructed sites averaged 0.007 feet with a Standard Deviation of 0.006 feet and a Range of 0.004
to 0.024 feet. The estimated absolute value of the vertical residuals averaged 0.008 feet with a Standard
Deviation of 0.007 feet and a Range of -0.05 to +0.04 feet. At the 95% Level of Confidence, the horizontal (2D)
movements reported below attained an estimated accuracy of better than 0.02 feet. The adjustment fixed AB02
and checked to AB61 and PVE3RP as shown below confirming the successful recovery of a stable reference
frame (coordinate system). Differences from the known fixed positions to the measured positions in this survey
are listed here with their north, east and vertical components in feet.
Differences in Feet
ID dN dE dZ_
AB02 0.000 0.000 0.000 Fixed
AB61 -0.006 0.009 0.020 Stable Check Point on Portuguese Point
PVE3RP -0.002 -0.004 0.072 Stable Check Point at City Hall
Addendum No. 2
Monitoring Survey No. M36 Report
Portuguese Bend Landslide Monitoring
May 12, 2023 Partial Monitoring Survey
Addendum No. 2: Report on the third of three annual Portuguese Bend Monitoring Surveys (M36). The average
date of the field survey is May 13th. This partial survey included 39 points (30 required) which are a sub-set of
the monitoring network. A minimally constrained adjustment was processed to develop NAD83 (2007) Epoch
2007.00 State Plane Coordinates and NAVD88 Heights. The estimated vector horizontal (2D) residuals at
moderately obstructed sites averaged 0.007 feet with a Standard Deviation of 0.004 feet and a Range of 0.002 to
0.030 feet. The estimated absolute value of the vertical residuals averaged 0.016 feet with a Standard Deviation
of 0.009 feet and a Range of -0.08 to 0.04 feet. At the 95% Level of Confidence, the horizontal (2D) movements
reported below attained an estimated accuracy of better than 0.02 feet. The adjustment fixed AB02 and checked
to PVE3RP as shown below confirming the successful recovery of a stable reference frame (coordinate system)
as shown below. Differences from the known fixed positions to the measured positions in this survey are listed
here with their north, east and vertical components in feet. AB61 was not accessible at the time of the survey.
Differences in Feet
ID dN dE dZ_
AB02 0.000 0.000 0.000 Fixed
AB61 ---- ---- ---- Deleted on future surveys to avoid public access/damage to environ
PVE3RP 0.020 -0.014 -0.067 Stable Check Point at City Hall
The Addendum Field Surveys, Equipment, Data Collection and Network Design were as described in the above
Initial Survey Report. The Winter and Spring Horizontal (2D) and Vertical Movements are summarized in the
“Periodic Horizontal & Vertical Movement in Feet” table below. The Direction of Movement is generally south
to south-southwest. See “PB MOVEMENT DATA POSTING 2007-20##.xlsx” for the direction, distance, and
confidence.
Ord. 675U
Exhibit D
Page 7 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 6 of 7
Note, a substantial increase in movement velocities was observed between the October 2022 and May 2023 surveys
compared to the previous four years. Points AB61, PB12, PB18 and PB26 were not accesible in the May 2023 Survey
due to an extraordinary spring growth of Mustard plants. PB09 was added in May as a nearby substitute for PB12. A
Pepper Tree has overgrown PB18 to the point where it will be abandoned if not cleared for future surveys.
“Partial Monitoring” Movements
Periodic Horizontal & Vertical Movements in Feet
Oct. 10, 2022 (M34)
to
March 13, 2023 (M35)
to
Oct. 10, 2022 (M34)
to March 13, 2023 (M35)
= 5.0 mo
May 12, 2023 (M36)
= 2.0 mo
May 12, 2023 (M36)
= 7.0 mo
Monitoring
Point
Movement
Distancs
Elevation
Change
Monitorin
g Point
Movement
Distance
Elevation
Change
Monitoring
Point
Movement
Distance
Elevation
Change
AB02 0.00 0.00 AB02 0.00 0.00 AB02 0.00 0.00
AB04 0.93 -0.12 AB04 0.87 -0.08 AB04 1.80 -0.20
AB13 0.31 -0.18 AB13 0.38 -0.06 AB13 0.70 -0.24
AB16 0.13 0.02 AB16 0.16 0.04 AB16 0.29 0.06
AB17 0.05 0.01 AB17 0.01 0.01 AB17 0.05 0.03
AB20 0.38 -0.06 AB20 0.46 0.04 AB20 0.84 -0.02
AB24 0.34 -0.06 AB24 0.38 0.05 AB24 0.73 -0.01
AB50 0.25 -0.02 AB50 0.30 0.05 AB50 0.55 0.03
AB53 0.32 -0.13 AB53 0.41 0.03 AB53 0.74 -0.10
AB58 0.25 -0.14 AB58 0.35 -0.03 AB58 0.60 -0.16
AB59 0.38 -0.10 AB59 0.47 -0.08 AB59 0.85 -0.17
AB60 0.39 -0.06 AB60 0.41 0.01 AB60 0.80 -0.05
AB61 0.01 0.02
AB62 0.72 -0.11 AB62 0.68 -0.03 AB62 1.40 -0.14
AB65 0.20 -0.03 AB65 0.24 -0.01 AB65 0.43 -0.04
AB66 0.27 -0.12 AB66 0.35 -0.02 AB66 0.63 -0.14
AB67 0.15 -0.08 AB67 0.18 0.02 AB67 0.32 -0.07
AB68 0.23 -0.12 AB68 0.31 -0.05 AB68 0.54 -0.17
AB70 0.38 -0.06 AB70 0.45 0.05 AB70 0.84 -0.01
AB73 0.36 -0.08 AB73 0.42 -0.01 AB73 0.78 -0.09
CR07 0.19 -0.24 CR07 0.25 -0.19 CR07 0.44 -0.43
CR50 0.03 -0.12 CR50 0.02 0.08 CR50 0.05 -0.04
FT06 0.41 -0.26 FT06 0.53 -0.21 FT06 0.93 -0.47
FT09 0.01 -0.11 FT09 0.03 0.08 FT09 0.04 -0.03
KC06 0.13 -0.12 KC06 0.20 -0.04 KC06 0.33 -0.16
KC07 0.02 -0.07 KC07 0.02 0.01 KC07 0.01 -0.06
KC13 0.08 -0.01 KC13 0.11 0.06 KC13 0.19 0.06
KC16 0.01 -0.05 KC16 0.03 0.04 KC16 0.04 -0.01
KC17 0.11 -0.08 KC17 0.20 0.03 KC17 0.31 -0.05
PB04 0.63 -0.12 PB04 0.61 -0.05 PB04 1.23 -0.17
PB09 1.00 -0.05
PB12 0.62 -0.08
PB13 0.48 -0.02 PB13 0.60 0.04 PB13 1.08 0.02
PB18 0.39 -0.11
PB26 0.46 -0.13
PB54 0.39 -0.04 PB54 0.54 0.03 PB54 0.93 -0.02
PB55 0.50 -0.16 PB55 0.58 -0.17 PB55 1.06 -0.33
PB59 0.77 -0.22 PB59 0.72 -0.08 PB59 1.49 -0.30
PB67 0.96 -0.20 PB67 1.12 -0.13 PB67 2.08 -0.33
PB68 0.57 -0.09 PB68 0.59 -0.04 PB68 1.16 -0.12
PB69 0.63 -0.12 PB69 0.69 -0.07 PB69 1.32 -0.19
PB70 0.54 -0.28 PB70 0.60 -0.19 PB70 1.14 -0.48
PB71 0.47 -0.13 PB71 0.57 -0.15 PB71 1.03 -0.27
Note: Movements greater than 0.02 feet (1/4") are deemed to have moved. See attached "PB MOVEMENT DATA POSTING" for a details.
Ord. 675U
Exhibit D
Page 8 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 7 of 7
PARTIAL ASSESSMENT of OBSERVATIONS
In the last seven months the movement velocities have accelerated over the average velocity for the previous
four years which saw an acceleration over the previous 15-20 years. A year is defined generally as 12 months
from the beginning of October to the end of September of the following year. Below are the average measured
movements for a sample of monitoring points from five to nine years back, one to four years back and this
partial year with a projection to the Fall of 2023. It appears the Abalone Cove slide is beginning to match the
Portuguese Bend slide.
Movement Summary in Feet
2014-2018 2018-2022 2022-May 2023 2022-2023
ID 4 Yr.Av. Max. 4 Yr.Av. Max. 7 Months Projected for 1 Yr.
AB53 0.07 0.18 0.43 0.49 0.74 1.1 +/-
AB20 0.09 0.20 0.48 0.54 0.84 1.3 +/-
AB68 0.05 0.11 0.31 0.32 0.54 0.8 +/-
CR07 0.06 0.13 0.30 0.32 0.44 0.6 +/-
KC06 0.04 0.09 0.16 0.22 0.33 0.5 +/-
PB55 0.89 1.31 0.89 1.23 1.06 1.6 +/-
Velocities were stable prior to 2018. After the Fall of 2018 they increased about 3 to 6 fold at most points and
remained stable to the Fall of 2022. In the last seven months since the Fall of 2022 the velocities generally have
doubled more or less. The Projected Movements for the end of the year in the Fall of 2023 were based on the
previous years results.
RECOMMENDATION
Continuity in terms of consistency of the precision of the surveys and methods of reporting are necessary to
continue to evaluate future survey results relative to the 2007-2023 monitoring survey campaigns. If in the
future, monitoring survey campaigns are performed by others it is recommended the City of Rancho Palos
Verdes secure the services of an independent expert GNSS/Geodetic consultant to evaluate and validate results
to assure program integrity.
Clearing foliage and tree trimming to allow for full sky visibility for tracking satellites results in improved
accuracy and production. Points AB13, AB16, AB17, AB51, AB58, AB66 and PB18 have limited sky visibility
due to surrounding trees and would benefit from annual clearing. Improvements in GNSS (GPS) instrumentations
and constellations have helped mitigated some of these issues. A Pepper Tree has overgrown PB18 and it will be
abandoned if not cleared for future surveys.
SURVEYOR'S STATEMENT
This is the Fall 2022 through Spring 2023 Report on the procedures,
criteria, and results of the City of Rancho Palos Verdes Portuguese Bend
Landslide Monitoring Surveys. This survey was performed, and Report
prepared by me June 7, 2023 at the request of Ron Dragoo, Principal
Engineer of the City of Rancho Palos Verdes.
Ord. 675U
Exhibit D
Page 9 of 26
Ord. 675U
Exhibit D
Page 10 of 26
McGee Surveying Consulting
Page 1 of 4
1
August 6, 2023
Ramzi Awwad, City Engineer
City of Rancho Palos Verdes
30940 Hawthorne Blvd.
Rancho Palos Verdes, CA 90275
Subject: Report on Rancho Palos Verdes (RPV) Portuguese Bend and Klondike Cyn Landslide Monitoring in
Seaside in July and August 2023. Refer to the 2007-2023 Portuguese Bend Landslide Monitoring Reports for
more details and procedures utilized in this survey.
A portion of the Portuguese Bend Landslide Complex was monitored between July 12, 2023 and July 19, 2023
(average date July 15, 2023), and then again on August 2, 2023. The purpose was to monitor the movement in
the Klondike Canyon Slide and specifically the recent movements at the intersection of Dauntless & Exultant
Drives. Additionally, a sampling of points in the Abalone Cove Slide were observed with a single observation to
make a preliminary assessment in the gated community of recent movements (listed below). The expected
precision (referred to as noise) of repeat GNSS (satellite) observations based on extensive experience is
generally 0.02 feet or less; however, solar disturbances occurring during the period of the July surveys resulted
in a level of noise of 0.03 to 0.04 feet. To successfully measure actual movement, the measured movement
(referred to as signal) must exceed the noise. Thus, the movement is effectively the signal plus or minus the
noise.
In Klondike Canyon (KC), five
observations were made beginning
July 12 over a seven day period
and again 21 days after the first
day. All current KC monitoring
points and two new points set at
Dauntless & Exultant Drives were
monitored. The new points are
KC19 located about 100’ westerly
and KC20 located about 70’
southerly of the intersection.
Along with existing points KC06
located about 200’ westerly and
KC07 about 70’ east of the
intersection provided adequate
coverage of the area of visible
movement. The daily movements
in the first seven days was within
the range of the measurement
noise which limited the capability
to estimate actual movements. The overall assessment with the exception of KC07, indicates points KC06,
KC19 and KC20 moved westerly about 0.01 feet per day with no adverse changes in velocities. KC07 remained
unchanged. A better assessment of the velocities was possible after a sixth observation on August 2, 2023 in
which the accumulative movement sufficiently exceeded the noise to model the signal as listed in the table
below.
Ord. 675U
Exhibit D
Page 11 of 26
McGee Surveying Consulting
Page 2 of 4
2
Point Bearing Dist. Bearing Dist.
(degrees) (feet) (degrees) (feet)
July 12>July 19 July 12>August 2
FT091 * * * *
KC021 S 03 W 0.05 S 03 W 0.19
KC051 * * S 14 W 0.06
KC061 S 67 W 0.06 S 67 W 0.11
KC071 * * * *
KC131 * * S 22 E 0.06
KC141 * * * *
KC151 S 50 W 0.04 S 50 W 0.11
KC161 * * * *
KC171 S 24 W 0.02 S 24 W 0.10
KC181 S 10 W 0.05 S 10 W 0.26
KC191 N 85 W 0.07 N 85 W 0.09
KC201 N 78 W 0.06 N 78 W 0.09
* No Detectable Movement
Estimated Accuracy= 0.02 feet at 95% Confidence
Points around the intersection of Dauntless & Exultant Drives slowed, however it appears other points in the KC
Slide accelerated after the first seven days of observations. It is noted below that KC06 moved westerly 0.32 feet
between the May 12 and July 15 (about 0.005’/day) and 0.33 feet in the previous seven months since October
10, 2022. Except for KC07, KC14 and KC16 all other points in the Klondike Canyon Slide have accelerated in
this last year after having accelerated in the previous four years.
The following table provides a general assessment of movements since 2014. The 2014-2018 period is generally
representative of previous years back to 2007. In the last two months the movement velocities have accelerated
over the previous seven-month period between October 10, 2022 to May 12, 2023. In that seven-month period
the average velocities had accelerated over the previous four-year average which saw an acceleration over the
previous 8 or more years. A monitoring year is 12 months beginning and ending about the beginning of the
rainy season on October 1. Below are the measured movements for a sample of monitoring points for the
indicated periods with a projection for the full year of October 10, 2022 to October 2023 based on actual
measurements for the period October 10, 2022 to July 15, 2023.
Ord. 675U
Exhibit D
Page 12 of 26
McGee Surveying Consulting
Page 3 of 4
3
Movement Summary at Selected Points in Feet
2014-2018 2018-2022 Oct.10,2022 May 12, 2023 Oct.‘22-July‘23
to May 12,2023 to July 15, 2023
ID 4-Yr.Av./Max. 4-Yr.Av./Max. 7 Months 2 Months 1 Yr. Projection
AB17 0/0 0/0 0.05 <0.04? ?
AB20 0.09/0.20 0.48/0.54 0.84 0.74 2.11
AB53 0.07/0.18 0.43/0.49 0.74 0.65 1.85
AB58 0.07/0.14 0.35/0.41 0.60 0.54 1.52
AB60 0.07/0.17 0.45/0.46 0.80 0.63 1.91
AB67 0.03/0.04 0.16/0.18 0.32 0.21 0.71
AB68 0.05/0.11 0.31/0.32 0.54 0.50 1.39
AB70 0.49/0.52 0.84 0.69 2.04
AB73 *0.36/0.46 0.78 0.67 1.93
CR07 0.06/0.13 0.30/0.32 0.44 0.42 1.15
FT09 *0.02/0.03 0.04 0.03 0.09
KC02 0.05/0.11 0.22/0.30 ? 0.91/9 Mo. 1.21
KC05 0.03/0.06 0.10/0.15 ? 0.40/9 Mo. 0.53
KC06 0.04/0.09 0.16/0.22 0.33 0.32 0.87
KC07 0/0 0/0 0 0.02 ?
KC13 0.04/0.07 0.08/0.15 0.19 0.15 0.45
KC14 0/0 0.03/.04 ? 0.08 0.11
KC15 0.04/0.09 0.16/0.23 ? 0.61/9 Mo. 0.81
KC16 0/0 0/0 0 0.04 ?
KC17 0.04/0.09 0.14/0.19 0.31 0.28 0.79
KC18 *0.33/0.40 ? 1.28/9 Mo. 1.71
PB55 0.89/1.31 0.89/1.23 1.06 0.96 2.69
PB70 *0.53/0.82 0.82/1.15 1.14 0.79 2.56
* 3 Years
As stated above, velocities were fairly stable prior to 2018. After the Fall of 2018 they increased about 3 to 5-
fold at most points and remained fairly stable until the Fall 2022. Between October 10, 2022 and May 12, 2023
(seven months) the velocities accelerated, and accelerated again in the following two months as noted. The
one-year Projected Movements (October 2022 to October 2023) are annualized based on the accumulated
movements between October 10, 2022 and July 12, 2023.
Ord. 675U
Exhibit D
Page 13 of 26
McGee Surveying Consulting
Page 4 of 4
4
SURVEYOR'S STATEMENT: This report is based on record information
and a portion on field surveys and was prepared by me on July 23, 2022 and
revised August 6, 2023 at the request of Ramzi Awwad of the City of
Rancho Palos Verdes.
Ord. 675U
Exhibit D
Page 14 of 26
Ord. 675U
Exhibit D
Page 15 of 26
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Ord. 675U
Exhibit D
Page 16 of 26
Ord. 675U
Exhibit D
Page 17 of 26
Preliminary 10/30/23 Draft Survey Report
of the
Portuguese Bend Oct. 2022-Oct. 2023-May 2024
Land Movement Monitoring Surveys
for the
City of Rancho Palos Verdes
prepared by
McGee Surveying Consulting
Date: October 30, 2023 Revised ??
The Portuguese Bend Landslide is monitored on a tri-annual basis beginning with the initial survey of all
current monitoring points at the beginning of the rainy season in the fall of each year followed by two
subsequent partial monitoring surveys. This Report on the Initial Fall 2023 Monitoring Survey is followed by
two Addendums for the Winter and Spring Partial Monitoring Surveys published in spring 2024. Movements are
reported from the fall of 2022 to the spring of 2024. Movements are listed for these periods on Pages 5 & 7?.
October 10, 2022 (M34) to October 10, 2023 (M38 Initial Fall Survey),
October 10, 2023 (M34) to February ??, 2024 (M39 Winter Partial Survey),
February ??, 2024 (M39) to May ??, 2024 (M40 Spring Partial Survey), and
October 10, 2023 (M38) to May ??, 2024 (M40).
ATTACHMENT: “PB MOVEMENT DATA POSTING (Revised) 2007-Oct2023.xlsx”
OVERVIEW:
GNSS MONITORING NETWORK (M38)
McGee Surveying Consulting (MSC)
performed the Fall 2023 land
movement monitoring survey of the
Portuguese Bend Landslides. The
survey was planned, coordinated, and
executed by Michael McGee, PLS3945
of MSC who is responsible for the
field surveys, processing observations,
network adjustments, analysis, and
reports. This survey determined the
precise positions of 66 monitoring
points to assess their annual and
overall movements, three of which
(AB02, AB73 & PVE3RP) are used to
support and reference the survey
network and verify the recovery of the
reference frame. This survey included
10 new points set in September 2023,
two new points set in July for the
Klondike Canyon (Seaside) M37 Monitoring, and a new point KC24 set to replace KC02. Movements of new
points will be reported on subsequent surveys. Partial Surveys were conducted on 43? monitoring points in the
Winter and Spring of 2024 and included in this Report as Addendums [to be added?]. For details and procedures
utilized in this survey but not re-stated here, see the 2021-2022 Monitoring Survey Report published in May
2022 and previous reports. The October 2023 coordinates and the annual October 2022 to October 2023
movements are listed in the attached spreadsheet titled “PB MOVEMENT DATA POSTING (Revised) 2007-
Oct2023.xlsx”. An annual summary is listed below.
Ord. 675U
Exhibit D
Page 18 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 2 of 9
The horizontal and vertical positions of the monitoring points are based on the North American Datum of 1983
(NAD83) Epoch 2007.00 and the North American Vertical Datum of 1988 (NAVD 88) Datums (reference
frames). The NGS Geoid 03 is used to model orthometric heights (elevations) based on measured ellipsoid
heights referenced to NGS Benchmarks. Although more current models are available, Geoid 03 is retained to
maintain relative height differences over time as explained in said May 2022 Report. The latitudes and
longitudes determined by GNSS measurements are projected into NAD83 California State Plane Coordinates
Zone 5 in US Survey Feet.
The method for recovering the monitoring survey reference frame was modified in 2019 to improve the
efficiency and simplify the processing and analysis of the monitoring surveys. Since 2007, Point AB02 (at the
south end of Portuguese Point) has proven to be stable relative to PVE3 ((a California Spatial Reference Center
(CSRC) Continuously Operated GPS Station (CGPS) at City Hall)). The previous procedure was modified by
fixing point AB02 instead of PVE3 and checking to PVE3RP (a PK Nail set on the concrete base of PVE3 for a
reference mark to PVE3). The proven positions relative to PVE3 are listed below.
Pt# Latitude Longitude NAVD88 Ht Source)
AB02 33-44-13.84878 118-22-26.19243 116.47 ft Oct. 2018 position
PVE3RP 33-44-35.74239 118-24-15.27451 346.88 ft Average of 5 years
Comparing the positions of AB02 on Portuguese Point with PVE3RP at City Hall provides a redundant
verification that the reference frame is stable and successfully recovered for each monitoring survey.
The rate of movement (velocities) of the landslides have increased over the past five years compared to the
previous 12-year average. A notable increase in the velocities of the landslides were observed between the
October 2022 and May 2023, with additional increases in velocities observed between May and July and again
between July and the October 2023 survey. See “Assessment of Movements & Accelerations” addressed on
Page 8. Notwithstanding the 2019 process noted in the above paragraph, the processing of observations was
necessarily modified for this fall survey as follows.
The October 2023 observations were processed as follows. The Base Station AB73 was occupied over a six-day
period and was found to have moved about 0.016 feet per day as were other monitoring points in the slides. To
determine accurate position and therefore precision movements it was necessary to determine a daily position of
AB73. This was accomplished by processing the static data collected each day at AB73 with static data
downloaded from the CSRC for PVE3 and PVHS. PVE3 is and has always been the basic constraint for the
monitoring survey’s reference frame. PVHS was used to verify the stability of PVE3. Subsequently positions of
AB73 were computed for each day referenced to PVE3. The identity for processing the daily observations of
AB73 and related RTK measurements was to assign to AB73 the identity of AB731, AB732, AB733, AB734 &
AB735 for days 1 through 5 occurring on October 8, 9, 10, 11 & 13.
AB61 and AB20 have previously served as suitable GNSS Base Stations for referencing measured positions of
the monitoring points. AB61 is no longer accessed due to its environmental sensitivity. Presently AB73, located
on the US Pony Club property, is utilized as the Base Station. Access was obtained unilaterally by MSC from
the Pony Club manager. MSC has exclusive permission to enter the property which is confirmed prior to each
survey entry with the understanding that strict driving protocols are observed. This privilege at this time does
not extend to others. Point AB73 was not a planned monitoring point but given the increased rates of movement,
it fills in a gap between AB20 and AB50 and moves consistent with AB20.
The Fall 2023 Survey is the 38th Monitoring Survey. For data management purposes the point names are
prefixed with a sequential monitoring number to distinguish subsequent surveys. For example, on the 16 th
monitoring survey, AB02 was named M16AB02 where M16 indicates the sequence number since the first
Monitoring Survey “M01” in September 2007. The prefix is stripped in these Reports.
Ord. 675U
Exhibit D
Page 19 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 3 of 9
Ord. 675U
Exhibit D
Page 20 of 26
McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 4 of 9
GNSS Survey Parameters, Metadata & Equipment
Date of Annual Initial Survey: M38 – October 10, 2023 (mean date) between 0800-1700 PDST (+7 hrs for UTC).
Constellations: GPS (31 Satellites), Russian GLONASS (23 Satellites), Galileo (23 Satellites) and Beidue (40 Satellites).
Observables: L1 & L2 Carrier Waves on GPS, GLONASS and Beidue; and four Carrier Waves on Galileo Satellites
Data Epoch Rate - 0.2 seconds (20HZ) at the GS18 RTK Rover; 1 second RTK at the GS18 Base
Satellites: 20-40; GDOP: < 2; Elevation Mask: 0° at the Rover and Base Station
Ephemeris: Broadcast for RTK vectors.
Weather: Mostly calm clear skies, temperature 65-75° F, no significant weather.
Space Weather: Boulder K Index 1-3 averaging 2 (gauges ionospheric activity on a scale of 0-9; less than 6 preferred)
Equipment: GNSS Base Receiver Unit No.: M11, Operator: M. McGee, PLS; Occupied Base Station
GNSS Rover Receiver Unit No.: M10, Operator: M. McGee, PLS
Make & Model: Leica GS18T with integrated Antenna; Mount: Fixed Height Pole #4
Processing & Adjustments: Leica Infinity v4.0 and "Starnet-PRO” version 11.0.6 Software
Prior to 2019, geodetic grade GNSS receivers collected static satellite signal data for post processing. The
instrumentation was upgraded in 2020 to a Leica GS18 Base with a GS18T RTK Rover operating in real-time
with an FM radio system which utilizes the latest technology to deliver increased productivity and precision of
point positions. The GS18 receiver incorporates an Inertial Measurement Unit and tracks four Global Navigation
Satellite Systems (GNSS) including GPS, GLONASS, Galileo and Beidue Satellites. The differences in two
measured vectors are acceptable if they fall within 0.03 feet (1 cm) horizontally; otherwise, additional
measurements are obtained. Experience has shown the independent measurements agree generally 0.02 feet.
ADJUSTMENTS & ANALYSIS
Network Adjustment: A minimally constrained adjustment is utilized to develop NAD83 (2007) 2007.00
Epoch Zone 5 State Plane Coordinates and NAVD88 Heights of the monitoring points. The NAVD88
orthometric heights (elevations) are determined by combining the measured ellipsoid heights with the Geoid03
Model. Previously, Point AB02 was fixed, and the stability verified relative to PVE3RP which is two miles
westerly outside the influence of the land movements and noted above. AB02 is expected to be stable and
unaffected by the land movement; however, due to the substantially increased rates of movement resulting in
dynamically differential movements across the slide complex the process was modified to produce accurate
positions as noted above. This was accomplished by computing daily positions on the Base Station AB73
(AB731, AB732, AB733, AB734, AB735) relative to the reference frame fixed at PVE3 also noted above.
Listed here are the differences.
Differences in Feet
ID dN dE dZ_
AB02 -0.022 -0.008 0.000 Fixed Elevation & Horizontal Check
PVE3RP -0.010 -0.003 -0.055 Closure Check from PVE3 to AB73 to PVE3RP at City Hall
PVE3 0.000 0.000 Fixed Horizontal, CGPS Station at City Hall
PVHS -0.035 0.003 Horizontal Check on CGPS Station 2 Miles North of PB
Comments: Fixing PVE3 (original 2007 constraint) finds the differences at PVHS, PVE3RP or AB02 are
insignificant measurement noise. Given that AB02, PVE3RP, PVE3 and PVRS are in good relative agreement,
the survey reference frame is deemed stable and successfully recovered from which local land movements were
determined.
ACCURACY STATEMENTS
Vector Residuals: The two-dimensional vector residuals average 0.012 feet and the absolute value of the
vertical residuals average 0.016 feet as listed below. The vector residuals are based on a network adjustment of
independent point positions.
Vector Lengths(ft) Two Dimensional Residuals Absolute Vertical Residuals
Vary Average Average Std.Dev. Maximum Average Std.Dev. _ Range
131-16391 3792 0.012 0.006 0.029 0.02 0.02 -0.03 to +0.08
Ord. 675U
Exhibit D
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McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 5 of 9
Movement Accuracy: A point is deemed to have moved if, at the 95% level of confidence the horizontal
movement (signal) of a point between two epochs is greater than the 95% Error (noise). Based on multiple
independent occupations, the horizontal (2D) movements reported between October 2022 (M34) and October
2023 (M38) statistically attained a relative average accuracy of 0.014 feet at the 95% Level of Confidence with
a Standard Deviation of 0.004 feet and a Range of 0.01 to 0.03 feet. See the attached file “PB MOVEMENT
DATA POSTING (Revised) 2007-Oct2023.xlsx” for movements and errors estimates.
Table of Annual Movements of Monitoring Points
2D Horizontal and Vertical Movements in Feet
(M34) October 10, 2022 to (M38) October 10, 2023 = 12.0 Months
Listed below are the movement Azimuths (directions from North) in degrees, the two-dimensional horizontal
movements and vertical (elevation) changes during the period. Units are in US Survey Feet. See the attached spreadsheet
“PB MOVEMENT DATA POSTING (Revised) 2007-Oct2023.xlsx”. Note: The horizontal measured movement
confidence is estimated at +/-0.02’ (1/4”); therefore, movements of less than 0.03’ are statistically indeterminate. The
estimated vertical measured movement confidence is +/-0.05’. *Control Point: Verifies Stability of Reference Frame.
Point
ID
Azimuth° Horizontal
Movement
Vertical
Movement
Point
ID
Azimuth° Horizontal
Movement
Vertical
Movement
AB01 244 0.06 0.0 KC02 196 1.99 0.1
AB02 201 0.02 0.0 KC05 219 0.88 -0.1
AB04 223 4.80 -0.6 KC06 253 1.34 -0.5
AB05 231 3.51 -0.6 KC07 256 0.02 0.0
AB13 198 2.48 -0.6 KC13 193 0.70 0.1
AB16 191 1.20 0.0 KC14 259 0.12 -0.1
AB17 187 0.06 0.0 KC15 233 1.36 -0.4
AB20 199 3.06 -0.1 KC16 251 0.03 0.0
AB24 198 2.68 0.0 KC17 222 1.24 -0.3
AB50 236 1.99 0.2 KC18 202 2.86 -0.3
AB51 202 2.05 -0.2 PB04 203 3.62 -0.3
AB53 192 2.75 -0.4 PB06 200 3.35 -0.3
AB57 169 2.37 -0.7 PB07 201 3.85 -0.1
AB58 183 2.22 -0.4 PB08 201 3.61 0.0
AB59 186 3.17 -0.8 PB09 198 3.49 -0.1
AB60 204 2.69 -0.3 PB12 200 4.67 -0.3
AB62 203 3.73 -0.4 PB13 201 3.83 0.1
AB63 207 3.58 -0.9 PB18 187 3.51 -0.5
AB64 155 0.35 -0.1 PB20 199 4.23 -0.4
AB65 167 1.49 -0.3 PB21 195 3.93 -0.6
AB66 196 2.29 -0.5 PB26 192 3.94 -0.4
AB67 180 1.12 -0.2 PB27 195 4.18 -0.8
AB68 193 2.03 -0.6 PB29 200 4.02 -1.0
AB70 203 2.97 -0.1 PB54 196 3.39 -0.2
AB71 158 1.76 -0.6 PB55 199 3.86 -0.8
AB73 203 3.00 -0.3 PB59 199 4.11 -0.6
CR07 171 1.87 -1.6 PB67 194 5.93 -0.8
CR50 225 0.11 -0.1 PB68 202 3.49 -0.1
CR51 223 0.08 0.0 PB69 202 3.91 -0.3
CR53 231 0.21 0.0 PB70 207 3.58 -0.8
FT06 192 3.66 -1.7 PB71 198 3.65 -0.4
FT08 257 0.06 0.0 UB02 189 4.17 0.3
FT09 271 0.08 -0.1 *PVE3RP 195 0.01 0.0
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Exhibit D
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McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 6 of 9
MONITORING POINT MONUMENT NOTES & STATUS
See the May 2022 Survey Report for prior monument notes.
2023: 13 points added to the monitoring program as listed below
MONITORING POINT MONUMENT DESCRIPTIONS
For the NAD83 (2007) Epoch 2007.00 California State Plane Coordinates Zone 5 and
NAVD88 Heights, see the attached file “PB MOVEMENT DATA POSTING….” Spreadsheet.
See Point Descriptions Sheets for more details.
Point Brief Description
Points added in October 2023
PB72 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete
PB73 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete
PB74 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete
PB75 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete
CR54 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete
CW06 Found ½” x 48” Punched Rebar in Concrete Collar
CW08 Found 2” Mag nail in Concrete Base of 3’ Pedestal
KC19 2” Mag Nail Drilled in a Concrete Curb on South side of Dauntless
KC20 2” Mag Nail Drilled in a Concrete Curb on West side of Excelsior
KC21 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete
KC22 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete
KC23 2” Mag Nail Drilled in a Concrete Curb on South side of
KC24 2” Mag Nail Drilled in the Southwest Corner of a Concrete Vault for Drop Inlet;
Replacement for KC02
Addendum No. 1
Monitoring Survey No. M39 Report
Portuguese Bend Landslide Monitoring
February ??, 2024 Partial Monitoring Survey
Information to be completed after the February 2024 Survey
Addendum No. 2
Monitoring Survey No. M40 Report
Portuguese Bend Landslide Monitoring
May ??, 2024 Partial Monitoring Survey
Information to be completed after the May 2024 Survey
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Exhibit D
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McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 7 of 9
Information to be completed after the February & May 2024 Surveys
Horizontal confidence in measured movements is estimated at +/-0.02’ (1/4”) at 95%; movements of less than
0.03’ are statistically indeterminate. The estimated confidence in measured vertical movement is +/-0.05’.
“Partial Monitoring” Movements
Periodic Horizontal & Vertical Movements in US Survey Feet Oct. 10, 2023 (M38)
To
Feb. ??,, 2024 (M39)
to
Oct. 10, 2023 (M38)
to
Feb. ??, 2024 (M39)
=4.5? mo
May ??, 2024 (M40)
= 3.0 mo
May ??, 2024 (M40)
= 7.0? mo
Monitoring
Point
Horizontal
Distancs
Vertical
Change
Monitoring
Point
Movement
Distance
Vertical
Change
Monitoring
Point
Horizontal
Distance
Vertical
Change
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Exhibit D
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McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 8 of 9
ASSESSMENT of MOVEMENTS & ACCELERATIONS
Others had performed monitoring surveys of land movement between 1994 and 2006. MSC assumed
responsibility for the Portuguese Bend Monitoring Program in 2007. The annual measured movements between
2007 and 2018 were fairly small and stable as shown below by the averages and maximums of a sampling of
points for the 2014-2018 period compared with the 2018-2022 period. In the fall of 2019, the annual average
rate of movements (velocities) increased 4 to 6 times and then remained stable for the next four years as shown
below for the 2018-2022 period. Note: The year is defined as the 12-month rainy season beginning October first
each year.
Annual Average Movements in Feet, Maximum Movements & Change in the Average of a Sample of Points
2014-2018(4 Yrs) 2018-2022(4 Yrs) Change in
ID Average Max. Average Max.__ _ Average
AB20 0.09 0.20 0.48 0.54 +5X
AB53 0.07 0.18 0.43 0.49 +6X
AB68 0.05 0.11 0.31 0.32 +6X
CR07 0.06 0.13 0.30 0.32 +5X
KC06 0.04 0.09 0.16 0.22 +4X
PB55 0.89 1.31 0.89 1.23 +1X (No Change)
Then in the last twelve months between October 2022 and October 2023, the annual rate of movements
accelerated again. The table below shows a sample of points within the Abalone Cove, Klondike Canyon and
Portuguese Bend Landslides. The left half of the table compares the annual movements and rate of movements
per month for the October 2021-October 2022 with the October 2022-October 2023 period. The annual rate of
movement for the sample averages for each landslide increased 6, 8 and 5 times respectively in the last 12
months. However, in the last 12-month period (October 2022-October 2023), accelerations are noted in the first
seven months and again in the last five months as shown in the right half of the table below.
In the first seven months of October 2022-October 2023, the average rate of movements for these samples in
each slide increased 3, 4 and 2 times respectively over the previous 12-month period (October 2021- October
2022).
In the last five months of October 2022-October 2023, the average rate of movements for the samples in each
slide increased 4, 4 and 3 times respectively over the previous seven months.
Movements & Rate of Movement per Month in US Survey Feet M32 > M34 (12 Mo.) M34 > M38 (12 Mo.) M34 > M36 (7 Mo.) M36 > M38 (5 Mo.)
Point Oct '21 > Oct '22 Oct '22 > Oct '23 Oct '22 > May '23 May '22 > Oct '23 Movement Rate/Mo Movement Rate/Mo Movement Rate/Mo Movement Rate/Mo
AB20 0.51 0.042 3.06 0.255 0.84 0.119 2.22 0.444
AB53 0.49 0.041 2.75 0.229 0.74 0.105 2.01 0.403
AB58 0.41 0.034 2.22 0.185 0.60 0.085 1.62 0.325
AB60 0.45 0.038 2.69 0.224 0.80 0.114 1.90 0.379
AB67 0.18 0.015 1.12 0.094 0.32 0.046 0.80 0.160
AB68 0.32 0.027 2.03 0.169 0.54 0.077 1.49 0.299
AB70 0.48 0.040 2.97 0.248 0.84 0.120 2.14 0.427
CR07 0.31 0.026 1.87 0.156 0.44 0.062 1.43 0.287
Av Move 0.39 0.033 2.34 0.195 0.64 0.091 1.70 0.340
KC06 0.16 0.014 1.34 0.111 0.33 0.047 1.01 0.202
KC13 0.09 0.007 0.70 0.058 0.19 0.027 0.51 0.102
KC17 0.14 0.012 1.24 0.104 0.31 0.044 0.93 0.187
Av Move 0.13 0.011 1.09 0.091 0.27 0.039 0.82 0.163
PB55 0.80 0.067 3.86 0.321 1.06 0.151 2.80 0.560
PB70 0.72 0.060 3.58 0.299 1.14 0.163 2.44 0.488
Av Move 0.76 0.063 3.72 0.310 1.10 0.157 2.62 0.524
Ord. 675U
Exhibit D
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McGEE SURVEYING CONSULTING
5290 Overpass Road, Ste#107, Santa Barbara, CA 93111
Page 9 of 9
RECOMMENDATION
Continuity in consistency of the methods, precision and reporting are necessary to continue to evaluate survey
results relative to the prior 2007-2024 monitoring survey campaigns. These monitoring survey campaigns
require the services of an independent GNSS/Geodetic expert to evaluate and validate results to assure program
integrity.
Clearing foliage and tree trimming are a necessary on-going task to assure as much sky visibility as possible for
tracking satellites to obtain the required precision and productivity. Although improvements in GNSS (GPS)
technology and additional constellations help mitigated some of these issues. Points AB13, AB16, AB17, AB51,
AB58, AB66 and PB18 are examples of points with limited sky visibility benefiting from annual clearing.
SURVEYOR'S STATEMENT
This is the Fall 2023 through Spring 2024 Report on the procedures,
criteria, and results of the City of Rancho Palos Verdes Portuguese Bend
Landslide Monitoring Surveys. This survey was performed, and Report
prepared by me on October 30, 2023 and updated June ??, 2024 at the
request of Ramzi Awaad, City Engineer of the City of Rancho Palos
Verdes.
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4332 DAUNTLESS
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SC6022 1
CSA Project No. SC6022
MEMORANDUM
TO: Katie Lozano, Open Space Manager
CC: Ara Mihranian, City Manager
William Wynder, Elena Gerli, and John Fox, City Attorneys
Cory Linder, Director of Recreation and Parks
Ramzi Awwad, Public Works Director
Taylor Fox, Senior Park Ranger
FROM: Michael Phipps, CEG 1832, Contract City Geologist
Christopher Dean, CEG 1751, Contract City Geologist
Matthew Janousek, GE 3005, Contract City Geotechnical Engineer
RE: Preliminary Geotechnical Assessment of Recent Land Movement in the Portuguese
Bend Reserve and Impacts to Burma Road Trail, Rancho Palos Verdes
DATE: September 29, 2023
_____________________________________________________________________________________________________________
INTRODUCTION
In accordance with your request, this memorandum has been prepared to provide a preliminary
geotechnical assessment of recent land movement within the Portuguese Bend Reserve (PBR) with a
specific focus on the impacts of land movement to the Burma Road Trail. We understand that the PBR
is one of the City’s most popular land reserves, it is heavily used by the public for recreation and is also
used by public utilities including Southern California Edison and California Water Service Company.
A portion of the PBR is underlain by the historically active Portuguese Bend Landslide (active since
1955-56) as well as the Ancient Portuguese Bend Landslide Complex. Some areas of the Reserve are
now experiencing significant land movement and ground surface manifestation that is beyond the
limits of the historically active and previously mapped Portuguese Bend Landslide, resulting in
damage to trails and fire roads which provide access for public safety, utilities, maintenance,
conservation, and public recreation. Cotton, Shires and Associates, Inc. (CSA) geologists have been
requested by the City to observe various landslide-related issues in the Reserve involving damage to
trails since 2021 and the SCE transmission lines along Burma Road since the summer of 2022. In 2021
we also began a detailed review of Global Positioning Satellite (GPS) monitoring data for survey
monuments both within and outside the PBR, including points within the Abalone Cove Landslide,
Klondike Canyon Landslide, and elsewhere within the Ancient Portuguese Bend Landslide Complex.
A comprehensive reconnaissance of the PBR was conducted by vehicle with City staff on June 28, 2023.
Following this field visit, the City’s Open Space Manager requested a report addressing the following
items:
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Exhibit F
Page 2 of 14
SC6022 2
• Information and a map presenting our observations of where new landslide scarps are forming;
• An evaluation of whether Burma Road is currently able to accommodate vehicles, ranging from
smaller Park Ranger trucks to heavy equipment used by utility companies and fire department,
and if it is currently able to accommodate vehicles, an estimate of how long the road will remain
stable;
• Recommendations for re-routing Burma Road (if necessary) to areas less prone to land
movement as the fire road is needed for the City, fire department, and utility companies;
• Consideration of recommendations for additional warning signage due to the increased land
movement to warn recreational users (hikers, bikers, horseback riders) and authorized outside
agency personnel who drive the Reserve fire roads;
• Recommendations for a maintenance plan to fill fissures and keep Burma Road passable to
pedestrians and vehicles, as the fissures have become too significant for park rangers to fill in
with shovels.
This memorandum will address these requested items, based upon our field observations and geologic
mapping, analysis of GPS monitoring data, background knowledge of the area, and professional
experience.
PREVIOUS WORK
Previous City-requested reconnaissance and observation of trail conditions in the PBR performed by
CSA geologists have included the following:
• 8/27/21: Burma Road trail reconnaissance (fissures/ground movement)
• 9/29/21: Burma Road and Garden Trail reconnaissance (fissures/ground movement)
• 1/5/22: Burma Road trail reconnaissance (fissures/ground movement)
• 8/31/22: Burma Road trail reconnaissance, meeting with SCE contractor and City staff,
(regarding power pole relocation due to fissures, ground movement)
• 3/8/22: Upper Burma Road trail reconnaissance (rockfall hazards)
• 4/5/23: Burma Road Trail, Garden Trail, and Rim Trail reconnaissance (fissures/ground
movement)
Findings and recommendations from these field visits have been routinely documented by either
memoranda or email addressed to City staff. Recent published documents include memoranda dated
February 9, 2022 (Burma Road/Rim Trail Junction) and May 19, 2023 (SCE Power Pole Relocation,
Burma Road).
Preliminary geologic mapping of the upper limits of active landsliding along the Burma Road trail and
vicinity was performed on June 28, 2023 and supplemented on September 22, 2023; however, this work
is incomplete and requires additional field effort. Because of the steep terrain, large mapping area, and
thick (inaccessible) vegetation in some areas, we have supplemented our field mapping with photo-
geologic mapping utilizing high-resolution Nearmap (vertical aerial) imagery captured on January 17,
2023 and June 17, 2023.
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Exhibit F
Page 3 of 14
SC6022 3
FINDINGS
Geologic Mapping: The Ancient Portuguese Bend Landslide Complex (APBLC) was first mapped by
the U.S. Department of the Interior Geological Survey (aka, USGS) in 1946 (shown as white area with
black dashed lines in the image below) and occupies a broad area on the south side of the Palos Verdes
Peninsula from the crest of peninsula to the Pacific Ocean.
U.S. Department of the Interior, 1946, Portion of Geologic Map of the Palos Verdes Hills, Los Angeles County, California
Within the APBLC, several large landslide masses have reactivated since the 1950s, including the
Portuguese Bend Landslide, Abalone Cove Landslide, Klondike Canyon Landslide, and Beach Club
Landslide. The Flying Triangle Landslide is in similar but higher terrain northeast of the Portuguese
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Exhibit F
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SC6022 4
Bend Landslide but is not considered part of the APBLC on regional geologic maps. These landslides
are depicted on the California Geological Survey’s Landslide Inventory Map of the Palos Verdes
Peninsula (2007, image below).
California Geological Survey, 2007, portion of Landslide Inventory Map of the Palos Verdes Peninsula
Burma Road (and Trail) is located along what was previously proposed to be the Crenshaw Boulevard
Extension, until the Portuguese Bend Landslide reactivated in 1956. The lower reach of Burma Road
trends southeast immediately uphill from the headscarp of the Portuguese Bend Landslide. Previous
site visits by our staff to the Burma Road area within the PBR beginning in 2021 were primarily in
response to reported “fissures” forming in multiple locations across trails. We understand that City
ranger staff have been routinely filling in the fissures with soil using hand tools. At other times heavier
grading equipment has been reportedly used by Cal Water to fill fissures and maintain the Burma Road
access to their facilities. Recent field mapping and GPS data suggest that these fissures are in fact the
incipient manifestations of headward enlargement of the Portuguese Bend Landslide as well as an
upslope manifestation of accelerated movement of a portion of the Ancient Portuguese Bend Landslide
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Exhibit F
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SC6022 5
Complex west of the active Portuguese Bend Landslide boundary. Four significant landslide scarps,
which initially manifested as ground cracking and small fissures in Burma Road, have now formed
across Burma Road, generally between the Eagle’s Nest Trail intersection on the west and the Rim Trail
intersection on the east.
Figure 1 (attached) was prepared on a Nearmap vertical color image taken January 17, 2023. The
approximate limits of the active Portuguese Bend Landslide are depicted in red. The upper area of
recent headward enlargement of the Portuguese Bend Landslide is depicted with yellow lines
delineating landslide scarps which can be seen crossing Burma Road in at least seven locations. While
the Burma Road trail has been repeatedly maintained by minor grading-leveling across these features,
the scarps have grown in height and width adjacent to the road over time, and in some locations,
grabens (wide pull-apart fissures) have formed in response to significant landslide movement. If not
maintained in this manner over the past several years, landslide scarps ranging from 1 to 8 feet in height
would extend across the road making it impassable to vehicles, cyclists, and even pedestrians. The
most severe location is the western (and uppermost, elevation-wise) scarp located between the Water
Tank trail and Eagle’s Nest Trail intersection with Burma Road. The landslide displacement at this
location has produced a scarp 6 to 8 feet in height and significantly displaced an SCE power pole that
is now leaning approximately 35-40 degrees out of plumb. Other scarps across Burma Road southeast
of this location are smaller, generally ranging from 1 to 4 feet in height adjacent to the road. Of note is
that these scarps have grown substantially in size since our June 28, 2023 reconnaissance.
The downslope limits of the new landslide scarps (yellow contacts on Figure 1) appear to be directly
connected to the Portuguese Bend Landslide at the eastern end; however, at the western end they are
not well-defined at the ground surface and additional field mapping is necessary to further delineate
the western margin. The western margin was observed crossing Kubota Trail and trending toward the
Vanderlip Trail, where it was lost in heavy vegetation. It is important to note that the western extent
of this new landslide movement is somewhat west of the head of the Portuguese Bend Landslide. It is
our interpretation that the western extent of this new landslide movement is occurring in response to
long-term creep displacement and recent acceleration of movement of the Ancient Portuguese Bend
Landslide Complex (APBLC) since October 2018.
GPS Survey Monitoring Data Review: GPS monitoring of survey monuments throughout the APBLC
area has been performed tri-annually since 2007 by McGee Surveying Consulting. In their June 6, 2023
Survey Report, McGee stated:
“In the last seven months the movement velocities have accelerated over the average velocity for the previous
four years which saw an acceleration over the previous 15-20 years……Velocities were stable prior to 2018. After
the Fall of 2018 they increased about 3 to 6 fold at most points and remained stable to the Fall of 2022. In the
last seven months since the Fall of 2022 the velocities generally have doubled more or less.”
This is a significant and important observation from the surveyor and comports with the past several
years of field observations by CSA staff of roadway distress and trail distress within the PBR, as well
as reports of street distress, building distress and utility line breaks throughout the various known
landslide areas. We have prepared several graphics based upon our own analysis of the GPS survey
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SC6022 6
monitoring data to further illustrate what is happening with the landslide ground movement. Figure
2 (attached) depicts horizontal displacements (in feet) and ground displacement vectors, for 12 selected
GPS survey monuments mostly located in the mid and upper Ancient Portuguese Bend Landslide
Complex. These figures are based upon McGee’s GPS monitoring of the survey monuments from
October 2018 to May 2023 (with the exception of two monuments which were last read in October 2022,
PB18 and AB71). Four of these monuments were also read in mid-July, 2023 and those movement data
are also presented. Two of the monuments, CR07 and FT06 are located on Burma Road outside of the
Portuguese Bend Landslide and indicate 1.67 feet and 3.09 feet of horizontal displacement over the ~4.5-
year period. The CR07 point moved an additional 0.42 feet in two months (through July 15, 2023),
which translates to ground movement velocity of about 2.5 feet per year. Most of the other points on
this figure are in the Ancient Portuguese Bend Landslide Complex (and mostly in LMA Zone 2) and
are indicating total displacements of approximately 1 to 3 feet (or average velocities of about 0.22 to
0.67 feet/year across the ~4.5-year period). Several of these points in LMA Zone 2 that were also
monitored in July, 2023 showed continued acceleration from May to July 2023, with calculated velocities
of ~1.25 feet/year at AB67 to ~3.9 feet/year at AB53. These are extraordinary rates of landslide
movement that, to our knowledge, have not been previously documented in the LMA Zone 2 area.
We have also reviewed and analyzed cumulative and incremental displacements from 2007-2023 for
six select survey monitoring points that are generally in the upper Portuguese Bend Landslide/Burma
Road area, including three points that are in the Ancient Portuguese Bend Landslide Complex west of
the historically active Portuguese Bend Landslide (i.e., in Landslide Moratorium Area Zone 2). These
six points are identified as:
• CR07 adjacent to Burma Road Trail;
• PB54 located within the “Landward Subslide” of the Portuguese Bend Landslide Complex;
• AB53, AB58 and AB59 located within the Ancient Portuguese Bend Landslide Complex
(Landslide Moratorium Zone 2); and
• FT06 adjacent to Burma Road Trail southeast of the Rim Trail intersection.
We have analyzed incremental displacement of these points versus 12-month antecedent rainfall, as a
measure of the landslide response to rainfall (Figure 3). A graph of cumulative displacement of these
points since 2007 is also presented in Figure 4. This graphed movement data indicates a clear
acceleration of movement beginning in late 2018 (as noted in the area labeled inflection point).
Accelerated landslide movements since late 2018 appear to be correlative with significantly above-
normal rainfall in three out of four rainfall seasons (2016-17, 2018-19 and 2019-20) which followed five
consecutive drier than normal rainfall seasons (2011-12 through 2015-16). The extraordinary rainy
season of 2022-23, where rainfall totals were more than 200% of average, has resulted in further
acceleration based upon limited monitoring data. A significant concern is that the movement velocities
have not declined back to the pre-2018 levels despite two significantly below-normal rainy seasons
(2020-21, one of the driest on record, and 2021-22). Also of note is that our rainfall data do not include
the impacts from Tropical Storm Hilary which dropped several inches of rain across most of southern
California in August, 2023.
Ord. 675U
Exhibit F
Page 7 of 14
SC6022 7
CONCLUSIONS AND RECOMMENDATIONS
Landslide movements throughout the Ancient Portuguese Bend Landslide Complex outside of the
historical boundary of the Portuguese Bend Landslide previously exhibited relatively low rates of creep
movement in the 11-year monitoring period of 2007-2018 for which we have readily available data.
Beginning in late 2018, and through the present, the survey data indicate a significant acceleration of
landslide movement. The movement of the Portuguese Bend Landslide also accelerated in this
timeframe. The cumulative displacements over this time have now manifested as headward
enlargement of the Portuguese Bend Landslide as well as new active landslide masses forming
northwest of the Portuguese Bend Landslide crown in Landslide Moratorium Area Zone 1, upslope
from LMA Zone 2. These new actively moving landslide masses are directly impacting Burma Road
and threaten future accessibility.
We understand this issue is also exceeding current resources (i.e., ranger staff) to monitor and maintain
the safety of the trails; primarily the heavily used Burma Road Trail. At this time, we consider this to
be a critical and evolving situation that poses risks to the general public who are accessing the PBR for
recreation, to utility infrastructure that traverses the landslide area, and to accessibility for other
stakeholders including conservation groups and the fire department. It is evolving because we are days
from entering the rainy season and most meteorologists and climatologists that we follow are citing
development of El Nino conditions in the Eastern Pacific Ocean and these are frequently associated
with wetter-than-normal rainfall conditions in southern California. We are also awaiting receipt of the
fall GPS survey data which are typically gathered in early October.
To address the City’s specific items, we offer the following:
Landslide Maps: For the purposes of this memorandum, a landslide overview map (Figure 1, attached)
was prepared to illustrate the entire affected area and impacts to Burma Road. We conducted field
mapping on much larger scale maps which allow for presentation of detailed observations; however,
these were not formally drafted and produced due to time constraints. We recommend that additional
field mapping be performed in an effort to further define the limits of active landsliding. Drafted larger
scale maps will be provided if necessary and/or upon request, to provide details in specific areas.
Burma Road Conditions and Maintenance Considerations: Given the current landslide movement
velocities, the newly identified landslides impacting Burma Road are active and considered unstable.
Burma Road only remains passable because of the reported efforts of other stakeholders to level the
ground surface across the landslide areas with larger equipment, in response to the creeping landslide
movement. We anticipate that the landslide movement will continue and is likely to be exacerbated by
the 2023-24 rainy season regardless of whether it is wetter or drier than historical averages. The filling
of fissures crossing the road with manual labor (by park rangers) has become untenable and such
measures are reportedly proving to be short-lived. The fissures, which are developing landslide scarps,
have widened and deepened in some areas due to significant ground movement. Smaller vehicles
(ranger trucks) are typically 2-3 tons and present lower risks when crossing the landslide areas;
Ord. 675U
Exhibit F
Page 8 of 14
SC6022 8
however, larger, heavier vehicles including fire trucks which typically weigh 10 to 20 tons present a
much larger transient load across the landslides, thus presenting a relatively greater risk.
Currently it is our opinion that Burma Road Trail should be closed to the public across the landslide
area unless it can be monitored on a daily basis by the park rangers. This is due to active landslide movement
directly impacting the road and posing significant risks to pedestrians, cyclists and horseback riders.
Ground leveling efforts to keep the road passable for vehicles may continue; however, crews should
avoid placing earth fill directly on the landslides because it adds weight and is a driving force of
landslide movement. Continued notching (lowering) of the trail approaches to the landslide scarps
may be the only effective solution in the short-term to maintain passage of vehicles. Care should also
be given to avoid ground-alterations that would direct more Burma Road drainage directly into the
landslide areas.
Burma Road Re-routing Considerations: Burma Road and trail occupy a portion of wider, leveled
ground graded during the proposed Crenshaw Boulevard extension (circa 1955-56). Several of the new
landslide scarps extend to near the north edge of the previously leveled area, thus, there does not
appear to be a feasible location to re-route the road through these areas. Furthermore, we do not see
an opportunity to completely re-route Burma Road outside of the former graded area without
consideration of massive grading and drainage improvements in steeply sloping areas, some of which
may also be in sensitive habitat area. There are also slope stability concerns north of Burma Road for
any considered re-route, and we are currently lacking information due to a lack of GPS monitoring
points north of Burma Road. The depth of movement of the new landslides is also unknown and at
best could only be estimated based on previous studies of the Portuguese Bend Landslide.
Consideration could be given to stabilizing the affected portions of Burma Road in its current location;
however, this would require an extensive geotechnical investigation, including geologic mapping,
installation of instrumented borings (e.g., slope inclinometer casings and piezometers), laboratory soil
testing, extensive slope stability analyses, and design of possible stabilization alternatives.
Stabilization, if technically feasible, might require a combination of extensive in-ground structural
measures (i.e., steel-reinforced concrete shear pins with tiebacks) and grading. Based upon our
experience, such mitigation would likely have a cost in the millions of dollars.
Additional Warning Signage: Additional warning signage due to the increased land movement, to
warn recreational users (hikers, bikers, horseback riders) and authorized outside agencies who drive
the Reserve fire roads, is reasonable and appropriate from a geotechnical perspective, particularly if the
City is going to keep Burma Road Trail and other potentially affected trails open to the public. As
mentioned above, the new landslide areas impacting Burma Road and Trail are currently unstable. The
landslide areas are currently moving (creeping) at velocities that are generally imperceptible to humans
and may seem innocuous from that perspective; however, over short periods of time the movement
creates significant hazards to trail users due to differential ground movement with associated ground
cracking and fissuring within the landslide masses as well as scarp formation at the movement
boundaries.
Ord. 675U
Exhibit F
Page 9 of 14
SC6022 9
Additional Recommendations: In addition to the specific items requested to be addressed by the City,
we have the following comments and recommendations:
• CSA previously issued a memorandum regarding the proposed SCE power pole relocation (May
19, 2023). At that time, we noted that the upslope extent of active landsliding had not been
geologically mapped (to our knowledge), the depth of landslide movement is unknown, and there
is a lack of GPS survey monitoring points north of Burma Road between Portuguese and Paintbrush
Canyons. We subsequently stated that due to this lack of information, it was difficult to assess the
impacts of future land movements on the proposed power pole relocation areas. It is our
understanding that SCE may be considering a larger scale relocation of their transmission line(s)
that are currently within the active landslide area, in lieu of the relocation project that we previously
reviewed. The existing transmission line along Burma Road is partially supported by power poles
located in actively moving landslides and at least two of the power poles have now been severely
compromised. This transmission line poses a significant risk if not de-energized.
• The above-ground water main which trends along Burma Road traverses portions of the new
landslide areas and is lacking ground support (i.e., the pipe is in the air) in some isolated areas. Our
concern is that the pipe may not have been designed for such conditions. This should be further
evaluated by the utility company responsible for the water main.
• Additional geologic mapping (on ground, possibly supplemented with drone photogrammetry)
should be performed in an effort to further define the areal extent of new active landsliding. This
information will be beneficial to the City for future evaluation of the safety of Burma Road and
other trails within the Portuguese Bend Reserve, and also useful to other stakeholders.
• Additional GPS monitoring points should be established north of Burma Road, between Portuguese
Canyon and Paintbrush Canyon. CSA will assist with recommended locations for these points if
requested by the City. We also recommend that the tri-annual GPS monitoring be performed on all
monuments in each monitoring session, in lieu of the partial monitoring that has been historically
performed in two of the three sessions per year.
• Periodic closures of the trail system within the PBR during and immediately after significant rainfall
events, as has been the policy of the City, should continue to allow for safety assessment of the trails
by ranger staff.
• Where feasible, park ranger staff should continue to do routine monitoring and filling of
ground fissures on other trails to keep the trails relatively safe; otherwise, the trails should be
closed.
We hope this memorandum provides the City of Rancho Palos Verdes with the requested information
and recommendations regarding Burma Road within the Portuguese Bend Reserve at this time. Please
contact us if you have further questions or concerns.
-o-
Ord. 675U
Exhibit F
Page 10 of 14
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Ord. 675U
Exhibit F
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Exhibit F
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Ord. 675U
Exhibit F
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Exhibit G
Page 2 of 23
1
Elena Gerli
From:Ara Mihranian <AraM@rpvca.gov>
Sent:Saturday, September 16, 2023 3:42 PM
Cc:William Wynder; Elena Gerli; Cory Linder; Daniel Trautner; Ramzi Awwad
Subject:Cal Water Pipe Break - Portuguese Bend Reserve
*** EXTERNAL SENDER ***
Honorable Mayor and City Councilmembers,
There has been another water main break in the Portuguese Bend Reserve off the Vanderlip Trail.
This trail was already closed due to a previous water main break.
As you can see from the photos, it was like a gushing river.
We now have an 8’ to 10’ deep rut in the trail.
I must admit they did respond timely to the scene.
However, we plan on billing Cal Water for the repairs including staff time.
Ara
From: Ara Mihranian <AraM@rpvca.gov>
Sent: Saturday, September 16, 2023 1:24 PM
To: Ara Mihranian <AraM@rpvca.gov>
Subject:
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5
Sent from my iPhone
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Exhibit H
Page 1 of 3
1
Elena Gerli
From:Ara Mihranian <AraM@rpvca.gov>
Sent:Friday, September 29, 2023 2:04 PM
To:Jerry Duhovic; raynesherman77@gmail.com; KIT & KWI
Cc:juxpraetor@aol.com; deirdre_heimer@yahoo.com; Pam Sherman; Lori Givens; Nic Grillo;
Anne Cruz; Steve Cummins; cruzanne@gmail.com; Joe Cruz; Karen Miller; smarshall7
@aol.com; PublicWorks; Donny Schmid; Larry Paul; Bob Locke; Noushkam, Nikki [US]
(SP); Brandy Forbes; Building and Safety Shared Mailbox; CodeEnforcement; CC; Eva
Albuja,
Subject:Seaview - Public Message
*** EXTERNAL SENDER ***
Folks,
I am requesng your assistance in disseminang this message to the residents with KCLAD, Seaview and PBC.
Residents’ observations and reports indicate that there has been increased subsidence in the
Seaview neighborhood over the past 48 hours.
In response, the City team is on-site as of the writing of this message.
Inspectors will be assessing properties from the street, and will accommodate any requests to inspect
the exterior and interior of individual residences.
The City’s Geotechnical team is on-site with Public Works Director Ramzi Awwad and will be studying
the area west of Schooner including outside the landslide boundary limits since it appears movement
is now occurring beyond the existing mapped area.
The City is asking that Cal Water personnel be on-site to immediately respond to water main breaks.
With recent land movement activity, the City strongly recommends that property owners turn off
sprinkler/irrigation watering systems for the foreseeable future to minimize additional water being
absorbed into the ground in the vicinity. Additionally, for those properties with swimming pools, if you
have experienced some water loss, the City requests that you refrain from refilling the pools at this
time and consider emptying your pool to prevent water entering the ground if cracking occurs. The
City will reach out in a future correspondence about a possible pool draining schedule, so owners can
start considering that next step.
The health and safety of the public and the protection of property, infrastructure, and the environment
are our top priorities. We are committed to keeping the community informed. You can find answers to
frequently asked questions and more information on the City’s webpage, and get updates by
subscribing to the Land Movement listserv at rpvca.gov/notify.
Have questions? Contact us at landmovement@rpvca.gov.
Ara
Ord. 675U
Exhibit H
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2
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Exhibit I
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Exhibit J
Page 1 of 4
STATE OF CALIFORNIA - BUSINESS, CONSUMER SERVICES AND HOUSING AGENCY GAVIN NEWSOM, Governor
DEPARTMENT OF HOUSING AND COMMUNITY DEVELOPMENT
DIVISION OF HOUSING POLICY DEVELOPMENT
2020 W. El Camino Avenue, Suite 500
Sacramento, CA 95833
(916) 263-2911 / FAX (916) 263-7453
www.hcd.ca.gov
November 6, 2023
Brandy Forbes, Director
Community Development Department
City of Rancho Palos Verdes
30940 Hawthorne Blvd.
Rancho Palos Verdes, CA 90275
Dear Brandy Forbes:
RE: Approval of Urgency Ordinance – Moratorium on Construction within the
Greater Portuguese Bend Landslide Complex
The purpose of this letter is to provide a determination to the City of Rancho Palos
Verdes (City) regarding the request to approve the adoption of Interim Urgency
Ordinance No. 674U (Ordinance), prohibiting any construction within the geographic
boundaries of the Greater Portuguese Bend Landslide Complex (Landslide Complex).
The California Department of Housing and Community Development (HCD) is
statutorily required to provide determination regarding proposed moratoria (Gov. Code,
§ 66300, subd. (b)(1)(B)(ii)). HCD received a request for approval for the proposed
Ordinance, met with the City staff, and reviewed relevant materials (e.g., staff letter,
resolution declaring a local emergency, Interim Ordinance No. 674U, land movement
monitoring surveys, etc.). Upon review of the written materials and discussion with the
local jurisdiction, HCD has determined that the current conditions of the Landslide
Complex pose an imminent threat to the health and safety of persons residing in the
area subject to the Ordinance.
Background
Since the 1950s to 1970s, three large landslides have been active in the City, including
Portuguese Bend Landslide (PBL), Abalone Cove Landslide (ACL), and the Klondike
Canyon Landslide (KCL). The Greater Portuguese Bend Landslide Complex or
Landslide Complex encompasses these three active landslides. Beginning in May of
2023, land movement has increased in the PBL and KCL complexes. Based on a
surveying report of PBL in October 2022 and revised assessment in June 2023,
“movement velocities have accelerated over the average velocity for the previous four
years, which saw an acceleration over the previous 15-20 years”.1 The accelerating
1 McGee Surveying Consulting, Conditions Assessment Report, dated October 19, 2022
and revised June 6, 2023, Page 2.
Ord. 675U
Exhibit J
Page 2 of 4
Brandy Forbes, Director
Page 2
land movement has destroyed homes, impacted the Portuguese Bend Reserve,
increased water main breaks, and caused roadway and utility line distress.
The City established Landslide Moratorium Area in 1978, imposing development
restrictions in response to the Landslide Complex. Since then, the City has adopted a
series of Interim Urgency Ordinances (Nos. 108U, 139U, 427U, 459U, 526, etc.) to
temporarily halt permit processing and construction, and make amendments to enforce
appropriate landslide mitigations measures in designated areas (Rancho Palos Verdes
Municipal Code sections 15.20.040 and 15.20.050).
The proposed Ordinance No. 674U is to encompass the entire Portuguese Bend
Landslide Complex (including ACL and KCL). The Ordinance would address an
imminent threat to public health and safety and prevent the exacerbation of existing
unstable geologic conditions caused by activities related to new construction within the
Landslide Complex. During the effective period of this Ordinance, the City will not
accept or consider any permit applications, nor issue any permits for construction on
any property within the Landslide Complex. This Ordinance also applies to any pending
applications and to any permits or entitlements that have issued but upon which
construction has not commenced.
The City has confirmed that no sites included in its housing element site inventory are
within the Landslide Complex. As a result, no such sites are subject to the proposed
Ordinance. Pursuant to Government Code section 65858, the City seeks to adopt and
enforce the proposed Ordinance that will begin with a 45-day period, following its date
of adoption, and if necessary extended for up to 22 months and 15 days.
The City is in the process of implementing a large-scale remediation project to stabilize
the Landslide Complex. The project will proceed in three phases: (1) repairing existing
fractures, (2) improving surface drainage of stormwater, and (3) installing a network of
hydraugers. Staff anticipates that 90 percent of the planning and Environmental Impact
Report certification will be complete by September 2024, and final engineering and
permitting will be complete by September 2025.
Local Moratorium Regulations Under the Housing Crisis Act (HCA)
Pursuant to Government Code section 66300, subdivision (b)(1)(B)(ii), a city cannot
enforce a moratorium that would limit housing development until it has submitted the
ordinance to and received approval from HCD. Conditions for imposing a moratorium,
or similar restrictions on housing development, must demonstrate “an imminent threat
to the health and safety of persons residing in, or within the immediate vicinity of, the
area subject to the moratorium” (Gov. Code, § 66300, subd. (b)(1)(B)(i)).
Ord. 675U
Exhibit J
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Brandy Forbes, Director
Page 3
HCD acknowledges the severity of the Portuguese Bend Landslide Complex’s condition
and the potential harm to public health and safety, and the environment, and anticipates
that the Ordinance will need to be extended beyond the 45-day period, pursuant to
Government Code section 65858. HCD hereby approves the adoption and enforcement
of Interim Urgency Ordinance No. 674U during the effective period of 45 days from its
adoption and its planned extension for up to 22 months and 15 days by the City of
Rancho Palos Verdes.
Conclusion
In summary, HCD approves the adoption and enforcement of the Ordinance and hopes
for a speedy resolution of this matter.
If you have any questions regarding the content of this letter or would like additional
technical assistance, please contact Mehrsa Imani, of our staff, at
mehrsa.imani@hcd.ca.gov.
Sincerely,
Shannan West
Housing Accountability Unit Chief
Ord. 675U
Exhibit J
Page 4 of 4