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ORD 674U ORDINANCE NO. 674U AN INTERIM URGENCY ORDINANCE OF THE CITY OF RANCHO PALOS VERDES, CALIFORNIA, TO ESTABLISH 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 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 (RPVMC § 15.20.020). (ii) Certain properties within Zone 2 of the LMA (the 16 Monks 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, 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 com/watch?v=WA3mwOISKjil. 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 suface 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 01203 0023/925024 8 Ordinance No 674U Page 2 of 12 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 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 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 01203 0023/925024 8 Ordinance No 674U Page 3 of 12 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. 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.com/california/palosverdes/wet-el-nio-ahead- brings-concerns-palos-verdes-landslide-complex?utm term=article-slot- 1&utm source=newsletter- daily&utm medium=email&utm campaign=newsletter&user email=10970c30f10d3992 86140af9d05d399c34c897422c415a4087d6e 1 cfd 9df 1 c29;https //www.kget.com/weathe r/weather-headlines/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. I 01203 0023/925024 8 Ordinance No. 674U Page 4 of 12 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 (land movementrpvca.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 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, 01203 0023/925024 8 Ordinance No 674U Page 5 of 12 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. 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 01203 0023/925024 8 Ordinance No 674U Page 6 of 12 the ordinance has been submitted to, and the City has received approval from, the Department of Housing and Community Development. 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; and WHEREAS, this Interim Urgency Ordinance is proposed 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; and WHEREAS, this Interim Urgency Ordinance is proposed 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; and 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. "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 01203 0023/925024 8 Ordinance No 674U Page 7 of 12 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. 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 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 01203 0023/925024 8 Ordinance No 674U Page 8 of 12 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 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. SECTION 5. Review and Study A. The City will contract with 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 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 01203 0023/925024 8 Ordinance No 674U Page 9 of 12 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. 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. 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 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 01203 0023/925024 8 Ordinance No 674U Page 10 of 12 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. 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 01203 0023/925024 8 Ordinance No 674U Page 11 of 12 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 45 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 3rd day of October, 2023, by a four- fifths vote of the entire City Council. Alfit if_A I John C kshank, Mayor Pro Tem ATTEST: 41e."4---- Teresa koka, City Clerk STATE OF CALIFORNIA ) COUNTY OF LOS ANGELES ) ss CITY OF RANCHO PALOS VERDES ) 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. 674U was duly and regularly adopted by the City Council of said City at a regular meeting thereof held on October 3, 2023 by the following vote: AYES: Alegria, Bradley, Seo and Mayor Pro Tem Cruikshank NOES: None ABSENT: Mayor Ferraro ABSTAINED:None I 'llyetC4rell'?".". le 01203 0023/925024 8 Ordinance No 674U Page 12 of 12 Ordinance No. 674U Exhibit A Page 1 of 2 Ordinance No. 674U Exhibit A Page 2 of 2 Ordinance No. 674U Exhibit B Page 1 of 2 Legend 1:14,066 Enter Map Title Enter Map Description Notes2,344.41,172.20 © City of Rancho Palos Verdes 2,344.4 0 Feet NAD_1983_StatePlane_California_V_FIPS_0405_Feet The information on this map is for reference only and may not be up-to-date. Please contact the City for more information. Street Centerlines Private Public Palos Verdes Reservoir City Boundary Adjacent Cities Palos Verdes Estates Rolling Hills Estates Rolling Hills Other Ocean Street Centerlines (2015) Private Public Landslide Zones (2017) Portuguese Bend Active Landslide Areas Abalone Cove Landslide Flying Triangle Landslide Klondike Canyon Landslide Portuguese Bend Landslide City Boundary Parcel 2020 Aerials Red: Band_1 Green: Band_2 Blue: Band_3 Ordinance No. 674U Exhibit B Page 2 of 2 Ordinance No. 674U Exhibit C Page 1 of 2 Avg Movement Per Year* •2007 to 2018 = 0.5” •2018 to 2022 = 1” - 2” (KC02 = 2.75”) (KC18 = 4”) •2022 to 2023 Annualized = See Map *Rate of Movement Varies Depending on Location & Year Klondike Canyon Monitoring Ordinance No. 674U Exhibit C Page 2 of 2 Ordinance No. 674U Exhibit D Page 1 of 14 Ordinance No. 674U Exhibit D Page 2 of 14 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 Ordinance No. 674U Exhibit D Page 3 of 14 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 Ordinance No. 674U Exhibit D Page 4 of 14 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. Ordinance No. 674U Exhibit D Page 5 of 14 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 Ordinance No. 674U Exhibit D Page 6 of 14 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. Ordinance No. 674U Exhibit D Page 7 of 14 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. Ordinance No. 674U Exhibit D Page 8 of 14 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. Ordinance No. 674U Exhibit D Page 9 of 14 Ordinance No. 674U Exhibit D Page 10 of 14 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. Ordinance No. 674U Exhibit D Page 11 of 14 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. Ordinance No. 674U Exhibit D Page 12 of 14 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. Ordinance No. 674U Exhibit D Page 13 of 14 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. Ordinance No. 674U Exhibit D Page 14 of 14 Ordinance No. 674U Exhibit E Page 1 of 47 4361 EXULTANT Ordinance No. 674U Exhibit E Page 2 of 47 Ordinance No. 674U Exhibit E Page 3 of 47 Ordinance No. 674U Exhibit E Page 4 of 47 Ordinance No. 674U Exhibit E Page 5 of 47 Ordinance No. 674U Exhibit E Page 6 of 47 Ordinance No. 674U Exhibit E Page 7 of 47 Ordinance No. 674U Exhibit E Page 8 of 47 Ordinance No. 674U Exhibit E Page 9 of 47 Ordinance No. 674U Exhibit E Page 10 of 47 Ordinance No. 674U Exhibit E Page 11 of 47 Ordinance No. 674U Exhibit E Page 12 of 47 Ordinance No. 674U Exhibit E Page 13 of 47 Ordinance No. 674U Exhibit E Page 14 of 47 Ordinance No. 674U Exhibit E Page 15 of 47 Ordinance No. 674U Exhibit E Page 16 of 47 Ordinance No. 674U Exhibit E Page 17 of 47 Ordinance No. 674U Exhibit E Page 18 of 47 Ordinance No. 674U Exhibit E Page 19 of 47 Ordinance No. 674U Exhibit E Page 20 of 47 Ordinance No. 674U Exhibit E Page 21 of 47 Ordinance No. 674U Exhibit E Page 22 of 47 Ordinance No. 674U Exhibit E Page 23 of 47 Ordinance No. 674U Exhibit E Page 24 of 47 Ordinance No. 674U Exhibit E Page 25 of 47 4332 DAUNTLESS Ordinance No. 674U Exhibit E Page 26 of 47 Ordinance No. 674U Exhibit E Page 27 of 47 Ordinance No. 674U Exhibit E Page 28 of 47 Ordinance No. 674U Exhibit E Page 29 of 47 Ordinance No. 674U Exhibit E Page 30 of 47 Ordinance No. 674U Exhibit E Page 31 of 47 Ordinance No. 674U Exhibit E Page 32 of 47 Ordinance No. 674U Exhibit E Page 33 of 47 Ordinance No. 674U Exhibit E Page 34 of 47 Ordinance No. 674U Exhibit E Page 35 of 47 Ordinance No. 674U Exhibit E Page 36 of 47 Ordinance No. 674U Exhibit E Page 37 of 47 Ordinance No. 674U Exhibit E Page 38 of 47 Ordinance No. 674U Exhibit E Page 39 of 47 Ordinance No. 674U Exhibit E Page 40 of 47 Ordinance No. 674U Exhibit E Page 41 of 47 Ordinance No. 674U Exhibit E Page 42 of 47 Ordinance No. 674U Exhibit E Page 43 of 47 Ordinance No. 674U Exhibit E Page 44 of 47 Ordinance No. 674U Exhibit E Page 45 of 47 Ordinance No. 674U Exhibit E Page 46 of 47 Ordinance No. 674U Exhibit E Page 47 of 47 Ordinance No. 674U Exhibit F Page 1 of 14 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: Ordinance No. 674U 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. Ordinance No. 674U 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 Ordinance No. 674U Exhibit F Page 4 of 14 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 Ordinance No. 674U Exhibit F Page 5 of 14 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 Ordinance No. 674U Exhibit F Page 6 of 14 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. Ordinance No. 674U 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; Ordinance No. 674U 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. Ordinance No. 674U 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- Ordinance No. 674U Exhibit F Page 10 of 14 Portuguese Bend Landslide (1956)post-1956activepre-1955Headward enlargement of landslide impacting Burma RoadPossibleheadward enlargementwest margin uncertainsouth of Kubota TrailBurma RdNarcisssa DriveSweetbay RoadAncient Portuguese Bend Landslide ComplexFigure 1Ordinance No. 674U Exhibit F Page 11 of 14 0.05 1.67/2.09 1.55 3.09 1.39 2.01/2.56 2.46/3.11 2.85 0.97/1.18 3.10 1.30 (10/22) 2.18 (10/22) Horizontal displacements and vectors from October 2018 to May 2023/July 2023 Figure 2Ordinance No. 674U Exhibit F Page 12 of 14 Figure 3Ordinance No. 674U Exhibit F Page 13 of 14 0.000.501.001.502.002.503.003.504.004.505.00Dec‐08 Jun‐09 Dec‐09 Jun‐10 Dec‐10 Jun‐11 Dec‐11 Jun‐12 Dec‐12 Jun‐13 Dec‐13 Jun‐14 Dec‐14 Jun‐15 Dec‐15 Jun‐16 Dec‐16 Jun‐17 Dec‐17 Jun‐18 Dec‐18 Jun‐19 Dec‐19 Jun‐20 Dec‐20 Jun‐21 Dec‐21 Jun‐22 Dec‐22 Jun‐23CUMULATIVE HORIZONTAL DISPLACEMENT SINCE 2007 (FEET)DATEGPS Monitoring DataSurvey Monuments ‐Upper Portuguese Bend Landslide/Burma Road AreaCumulative Horizontal Displacement 2007‐2023PB‐54AB‐53AB‐59CR‐07AB‐58FT‐06Note:   AB‐53, AB‐58 and AB‐59 are  in Landslide Moratorium Area Zone 2, within the Ancient Portuguese Bend Landslide ComplexCR‐07 and FT‐06 are outside the USGS 1946 Ancient Portuguese Bend Landslide ComplexPB‐54 is within the Landward Subslide of the Portuguese Bend Landslide (active 1956‐present)inflectionpointFigure 4Ordinance No. 674U Exhibit F Page 14 of 14 Ordinance No. 674U Exhibit G Page 1 of 23 Ordinance No. 674U 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: Ordinance No. 674U Exhibit G Page 3 of 23 2 Ordinance No. 674U Exhibit G Page 4 of 23 3 Ordinance No. 674U Exhibit G Page 5 of 23 4 Ordinance No. 674U Exhibit G Page 6 of 23 5 Sent from my iPhone Ordinance No. 674U Exhibit G Page 7 of 23 Ordinance No. 674U Exhibit G Page 8 of 23 Ordinance No. 674U Exhibit G Page 9 of 23 Ordinance No. 674U Exhibit G Page 10 of 23 Ordinance No. 674U Exhibit G Page 11 of 23 Ordinance No. 674U Exhibit G Page 12 of 23 Ordinance No. 674U Exhibit G Page 13 of 23 Ordinance No. 674U Exhibit G Page 14 of 23 Ordinance No. 674U Exhibit G Page 15 of 23 Ordinance No. 674U Exhibit G Page 16 of 23 Ordinance No. 674U Exhibit G Page 17 of 23 Ordinance No. 674U Exhibit G Page 18 of 23 Ordinance No. 674U Exhibit G Page 19 of 23 Ordinance No. 674U Exhibit G Page 20 of 23 Ordinance No. 674U Exhibit G Page 21 of 23 Ordinance No. 674U Exhibit G Page 22 of 23 Ordinance No. 674U Exhibit G Page 23 of 23 Ordinance No. 674U 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 Ordinance No. 674U Exhibit H Page 2 of 3 2 Ordinance No. 674U Exhibit H Page 3 of 3 Ordinance No. 674U Exhibit I Page 1 of 2 Ordinance No. 674U Exhibit I Page 2 of 2