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ORD 686U ORDINANCE NO. 686U AN INTERIM URGENCY ORDINANCE OF THE CITY OF RANCHO PALOS VERDES, CALIFORNIA, EXTENDING THE MORATORIUM ON THE ACCEPTANCE OR PROCESSING OF APPLICATIONS FOR AND ISSUANCE OF PERMITS, AND CONSTRUCTION OF ALL STRUCTURES WITHIN THE PORTUGUESE BEND LANDSLIDE COMPLEX ADOPTED BY ORDINANCE 674U AND EXTENDED BY ORDINANCE 675U, FOR AN ADDITIONAL 12 MONTHS, EXPIRING OCTOBER 2, 2025 WHEREAS, the City of Rancho Palos Verdes is affected by three large active landslides : the Portuguese Bend Landslide (the PBL), the Abalone Cove Landslide (the ACL), and the Klondike Canyon Landslide (the KCL) (collectively, the Landslides), and are part of the Greater Portuguese Bend Landslide Complex (the Landslide Complex). The Landslide Complex (depicted in Exhibit A) is comprised of an ancient landslide that measures upwards of 680 acres, and which extends beyond the boundaries of the individual Landslides. WHEREAS, the Landslides have been active since the 1950s and have moved at different rates at different times. the ACL and KCL have been managed, respectively, by the Abalone Cove Landslide Abatement District (ACLAD) and the Klondike Canyon Hazard Abatement District (KCHAD) (collectively, the Districts). WHEREAS, since May of 2023, the land movement in the Landslide Complex has increased significantly, and until recently has been accelerating at an exponential rate. 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, Section 65858(f) provides that "...upon termination of a prior interim ordinance, the legislative body may adopt another interim ordinance pursuant to this section provided that the new interim ordinance is adopted to protect the public safety, health, and welfare from an event, occurrence, or set of circumstances different from the event, occurrence, or set of circumstances that led to the adoption of the prior interim ordinance." WHEREAS, 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 The moratorium was extended by Interim Urgency Ordinance Nos. 439U, and repealed by Ordinance No. 469U, and its non-urgency version, Ordinance No. 526.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. 01203 0023/1001734 3 Ordinance No. 686U Page 1 of12 WHEREAS, the City Council finds that the circumstances today are different to the circumstances that prompted the 2005 moratorium: the movement is unprecedented in terms of speed and size, encompassing the entire Landslide Complex. WHEREAS, on October 3, 2023, by a four-fifths vote the City Council adopted Interim Urgency Ordinance No. 674U, which put into immediate effect a moratorium on construction in the Landslide Complex, including the acceptance or processing of applications for and issuance of permits, with some limited exceptions (the Moratorium). WHEREAS, on October 3, 2023, by a four-fifths vote the City Council also adopted Resolution No. 2023-047, declaring a state of local emergency in the Landslide Complex, pursuant to its authority under Chapter 2.24 of the Rancho Palos Verdes Municipal Code, and Section 8558 of the Government Code. The state of emergency is currently active, and has been extended by the City Council pursuant to Resolution Nos. 2023-56, 2023=61, 2024-05, 2024-13, 2024-20, 2024-44, and 2024-51. It is anticipated that the state of emergency will continue to be extended until the land movement is sufficiently stabilized. What constitutes sufficiently stabilized for the emergency to be lifted is a determination that will be made in consultation with the City Geologist, Mike Phipps of Cotton Shires and Associates, Inc. (CSA), in consideration of a number of factors. WHEREAS, on November 6, 2023, HCD approved the Moratorium for the entirety of the 24 months allowed by Government Code 65858, were the City to extend it for that period of time. In a letter to Brandy Forbes, Director of the City's Community Development Department, HCD acknowledged "the severity of the Portuguese Bend Landslide Complex's condition and the potential harm to public health and safety, and the environment, and anticipates that [the moratorium] will need to be extended beyond the 45-day period, pursuant to Government Code section 65858. HCD hereby approves the adoption and enforcement of Interim Urgency Ordinance No. 674U during the effective period of 45 days from its adoption and its planned extension for up to 22 months and 15 days by the City of Rancho Palos Verdes." HCD's November 6, 2023 letter is attached as Exhibit B. WHEREAS, on November 14, 2023, by a four-fifths vote the City Council adopted Interim Urgency Ordinance No. 675U, extending the moratorium for an additional 10 months and 15 days, which Ordinance is set to expire on October 2, 2024. WHEREAS, the City Council finds that the increase in land movement activity in the Landslide Complex is of great concern to the Districts, the City, and to the Palos Verdes Peninsula as a whole, and presents an imminent threat to the public health and safety. WHEREAS, since the adoption of Interim Urgency Ordinance No. 675U, the City Geologist has conducted additional field mapping throughout the Landslide Complex; observed conditions at various site-specific locations impacting residential neighborhoods, public infrastructure, and where trails have been impacted; reviewed additional survey and rainfall data; participated in weekly meetings of the RPV Landslide 01203 0023/1001734 3 Ordinance No 686U Page 2 of 12 Complex Working Group; and conducted site-visits to the boreholes being installed in advance of the emergency hydraugers. WHEREAS, Recent GPS survey data published by McGee Surveying Consulting for the period July 1, 2024 to August 1, 2024 were reviewed and analyzed. For all points monitored across the entire Landslide Complex, following are the key conclusions over the past month: • Overall average movement velocity decelerated 1%, with a range of 13% acceleration to -13% deceleration. • The ACL (within historical boundaries) decelerated 6% and had indicated land movement of between 2 to 4.5 feet over the past month. • The greater ACL (within the Greater Landslide Complex boundaries) decelerated 6.5% and had actual land movement of between 3.5 to 4.6 feet over the past month. • The PBL was not accelerating or decelerating and had indicated land movement of between 3 to 4.5 feet over the past month. • The western sub-slide portion of the PBL (including the ski jump) seems most active and is still accelerating, up about 5% compared to the previous month. • The KCL accelerated 4% and had indicated land movement of between 0.5 to 3.3 feet over the past month. i • New points established on the beach at Portuguese Bend Beach Club in April have risen about 3.5 to 4.5 feet vertically since they were established. • The Burma Road switchback points moved about 1.5-2.3 inches in the southwest direction over the past month. • Perimeter points are stable, indicating that the areas outside the landslide mapped boundaries are currently unchanged. • Recently, new points were established on Schooner Drive in the Seaview neighborhood to assess and affirm the limits of the Landslide Complex. The current GPS position of these points will be compared to the position at regular intervals moving forward to determine if there has been any movement. The GPS survey data published by McGee Surveying Consulting for the period through August 1, 2024 (McGee Survey Report) is attached as Exhibit C. WHEREAS, at the July 2, 2024 City Council meeting, the City Geologist reported that rainfall and the resulting runoff and infiltration into the Landslide Complex continues to adversely affect the landslide area, following a significantly wetter than average (193%) rainy season in 2022-23. The current rainfall total is 23.19 inches, approximately 170% of the season average over the past 67 years of the Rolling Hills Fire Station rain gauge. 01203 0023/1001734 3 Ordinance No. 686U Page 3 of 12 Since the July 2, 2024 update to the City Council, the City Geologist conducted additional field mapping throughout the Landslide Complex; observed conditions at various site- specific locations impacting residential neighborhoods, public infrastructure, and where trails have been impacted; reviewed additional survey and rainfall data; participated in the weekly Portuguese Bend Landslide Complex Working Group meetings; and conducted site-visits to the boreholes being installed in advance of the emergency hydraugers. CSA's land movement reports dated April 26, 2024 and June 25, 2024, are attached as Exhibits D and E, respectively. WHEREAS, the June 25, 2024 City Geologist report (Exhibit E), concludes that recent land movement rates (velocities) are approximately 7 to 11 inches per week in the ACL, 9 to 12 inches per week in the PBL, and 2 to 7 inches per week in the KCL (with highest velocities in the western KCL occurring between Klondike Canyon and the eastern PBL boundary). The City Geologist's report presents graphically the GPS monitoring data provided by the McGee 2024 GPS Report. Figure 1 depicts scaled, incremental displacements and movement vectors since October 2022. Figure 2 presents depicts displacement rates (i.e., movement velocities) and vectors since October 2022. Figure 3 depicts a contour map (aka "heat map") of displacement rates for the current April 17 through May 28, 2024 monitoring period. WHEREAS, recent land movement rates (velocities) remain approximately 7 to 11 inches per week in the ACL, 9 to 13 inches per week in the PBL, and 2 to 8 inches per week in the KCL. (See attachments A and B to the August 20, 2024 landslide update staff report, found here: https://rpv.granicus.com/MetaViewer.php?view id=5&clip id=4624&meta id=121588.) The significant and unprecedented change in movement behavior from historical movements of the PBL and ACL remains. WHEREAS, landslide movement continues to manifest at the ground surface in the form of scarps, fissures, grabens/sinkholes, tensional cracking, shear zones and thrust features. Due to the continued acceleration of the landslide, the ground movement features have continued to enlarge, expand, widen, or grow depending on the type of feature and location. Based upon recent field mapping, the total area of the active Landslide Complex has expanded by approximately five acres including the following areas: -- The eastern landslide boundary of the KCL is now manifesting approximately 50 feet farther east on Admirable Drive and 150 feet farther east on Exultant Drive; however, these boundaries appear to be consistent with historical mapping of the KCL and the location of a pre-development drainage course that is believed to define the easterly limit of prehistoric landsliding. -- The westerly boundary of the active Landslide Complex in the Abalone Cove Landslide area has expanded approximately 180 feet farther west at Narcissa Drive and on the York property at 6001 Palos Verdes Drive South (PVDS). This new expanded landslide movement is quickly deforming the Narcissa Drive curve and is 01203 0023/1001734 3 Ordinance No. 686U Page 4 of 12 the same movement that has displaced the administration building and caused major bulging of the parking lot at the Wayfarer's Chapel property. The Wayfarer's Chapel property is closed to the public, and the chapel itself has been dismantled and relocated. -- The Portuguese Beach Club area continues to experience major deformation along Seawall Road and bulging/uplift on the order of 4 to 5 feet across the beach on an east-west trend. This deformation appears to continue offshore into the PBL based on major emergence of land in the surf zone and nearshore zone at the southeasterly toe of the PBL. In this area, the seafloor has uplifted above mean sea level approximately 200 to 300 feet south of the former foreshore slope of the beach. -- Road conditions on PVDS across the lower Landslide Complex continue to be adversely impacted due to differential rates of land movement currently ranging from about 2 to 7 inches/week across the KCL, 8-12 inches per week across the PBL, and 5-10 inches per week across the ACL. Portuguese Point is being overridden by the landslide, resulting in failure of the historical rock wall along the Olmsted Trail and loss of beach access to Abalone Cove via Olmsted Trail. WHEREAS, the Palos Verdes Nature Preserve trail conditions within the Landslide Complex continue to worsen. Large parts of the Palos Verdes Nature Preserve (Preserve) are located within the Landslide Complex. Specifically, the Portuguese Bend Reserve, Abalone Cove Reserve, and parts of the Forrestal and Filiorum Reserves are located within the Landslide Complex. Many of these areas are seeing landslide-related damage including fissures, rockslides, sink holes, unstable trails, and significant erosion. Out of concern for public safety, and in consultation with the City Geologist, the City Manager has temporarily closed large areas of the Preserve consisting of approximately 11 miles. Most of these closures are focused in Portuguese Bend Reserve and Abalone Cove Reserve, but some are also in Filiorum and Forrestal Reserves. Staff continue to monitor these and other trails, and extensive repairs will likely be needed before these trails can be reopened for public use after the area has been stabilized. WHEREAS, land movement has continued in the Preserve; most notably in areas along Burma Road Trail, Toyon Trail, and Ishibashi Trail in Portuguese Bend Reserve, and Olmsted Trail in Abalone Cove Reserve. Portions of Burma Road are no longer accessible by vehicle, are difficult to traverse on foot, and have seen significant elevation changes in areas where fissures divide and break the road. Areas of Burma, near lower Rim Trail, are nearly impassable without step stools/ladders, or similar tools to assist with the elevation differences within the road/trail tread. These areas have continued to separate, creating drops of 15 feet or more along the trail. Many locations are almost unrecognizable, with little to no trail remaining. Olmsted Trail has ongoing land slippage and reoccurring slides, causing damage to old retaining walls and burying infrastructure installed in early 2024. Newer fissures on Vanderlip Trail and Gary's Gulch Trail have continued to expand and develop. Many areas remain additionally damaged from the heavy February/March 2024 storms including elevation changes, increased erosion, and additional and expanded fissures. (Recent photos of trail damage attached as Exhibit F.) 01203 0023/1001734 3 Ordinance No 686U Page 5 of 12 WHEREAS, due to the continued significant land movement and how it is manifesting at the ground surface in the form of scarps, fissures, grabens/sinkholes, tensional cracking, shear zones and thrust features, some residential structures and the utilities serving properties in the Landslide Complex have suffered damage and loss of function. (Recent photos of roads and homes damage attached as Exhibit G.) WHEREAS, roadways, water mains, sewer pipes, gas lines, and electrical power poles have all been impacted by the land movement throughout the Landslide Complex. The Southern California Gas Company shut off gas services to approximately 135 households on July 29, 2024 due to safety concerns. On July 30, 2024, Southern California Edison issued a statement that "On Oct. 3, 2023, the city of Rancho Palos Verdes declared a local emergency due to accelerated land movement and subsidence. Over the past 18,months, there has been considerable land movement, putting the utilities serving the area and multiple properties at risk. Southern California Edison's service to select properties may be discontinued if conditions warrant...." (SCE's full statement can be found here: https://energized.edison.com/rpv.) SCE has previously cut off service to 3 properties on Vanderlip Drive because of the land movement. WHEREAS, on August 6, 2024, the City Council adopted Resolution No. 2024-52, declaring a state of local emergency in the Portuguese Bend Community on the grounds of a sudden shortage of energy, based on Southern California Gas shutting off gas service to approximately 135 homes in the PBL. WHEREAS, on August 20, 2024, the City Council received an update from Ramzi Awwad, Director of Public Works, and the City Geologist, that the land movement is primarily due to a deeper slip plane that is approximately 330 feet below the surface (the Altamira slip plane), and may encompass more than the PBL, requiring a rethinking of the mitigation approach on a holistic level. 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...." WHEREAS, the City Council continues to find 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. 01203 0023/1001734 3 Ordinance No 686U Page 6 of 12 (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, pursuant to the provisions of the California Environmental Quality Act, Public Resources Code Sections 2100 et. seq. ("CEQA"), the State's CEQA Guidelines, California Code of Regulations, Title 14, §15000 et. seq., the City's Local CEQA Guidelines, and Government Code §65962.5(f) (Hazardous Waste and Substances Statement), it has been determined that the adoption of the Urgency Ordinance to impose a moratorium on the acceptance or processing of applications, issuance of permits, and construction in the Districts is exempt from CEQA, pursuant to Section 15061(b)(3). This Interim Urgency Ordinance is exempt because it proposes to impose a moratorium all construction on properties within the Districts and it can be seen with certainty that there is no possibility that the activity in question may have a significant effect on the environment. WHEREAS, this Interim Urgency Ordinance is proposed to allow the City to continue to address and mitigate an imminent threat to public health and safety and therefore is exempt from CEQA pursuant to Public Resources Code, Section 21080(b)(4) and CEQA Guidelines, Section 15269. WHEREAS, this Interim Urgency Ordinance is proposed to allow the City to continue to protect the environment by preventing the exacerbation to existing unstable geologic conditions caused by activities related to new construction and therefore is categorically exempt from CEQA pursuant to CEQA Guidelines, Section 15308 and none of the exceptions to this exemption set forth in CEQA Guidelines, Section 15300.2 apply to this Interim Urgency Ordinance. WHEREAS, on August 20, 2024, the City Council issued a report outlining the measures the City is taking to address the conditions that gave rise to this moratorium, as required by Section 65858(d) of the Government Code, in the form of a staff report that provided Council with a comprehensive update on the actions taken so far to alleviate the conditions requiring adoption of an interim urgency ordinance. The staff report can be found here: https://rpv.granicus.com/MetaViewer.php?view id=5&clip id=4618&meta id=121381. 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 01203 0023/1001734 3 Ordinance No. 686U Page 7 of 12 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 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. II 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, 111 01203 0023/1001734 3 Ordinance No 686U Page 8 of 12 111 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 meeting the City's RHNA, and instead will endanger the existing housing and the area's residents. D. The City Council therefore finds that in order to protect the health and safety of the residents of the Landslide Complex, the City, and the Palos Verdes Peninsula, it is necessary to adopt this Interim Urgency Ordinance. SECTION 4. Authority and Effect A. The State Planning and Zoning Law, Government Code Section 65000 et seq., broadly empowers the City to plan for and regulate the use of land in order to provide for orderly development, the public safety, health, and welfare, and a balancing of property rights and the desires of the community and how its citizens envisions their city. B. Government Code Section 65858 expressly authorizes the City, in order to protect public safety, health, and welfare, to adopt an Interim Urgency Ordinance prohibiting a use that is in conflict with a contemplated general plan, specific plan, or zoning proposal that the legislative body, planning commission, or the planning department is considering or studying or intends to study within a reasonable time, provided that the urgency measure shall require a four-fifths vote of the legislative body for adoption, and shall be of no further force and effect 45 days from its date of adoption, unless duly extended for an additional 10 months and 15 days. The Interim Urgency Ordinance may be extended for a further 12 months. SECTION 5. Review and Study The City has been in the process of implementing a Landslide Remediation Project for the PBL. The Project's purpose was, 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 hydraugers. The project as originally designed has three components: Component I - Repair of the Existing Fractures, Component II - Surface, Drainage Improvements, and Component III - Below-Grade Hydraugers. The purpose of the project is to install a number of hydraugers, to be constructed below grade, designed 01203 0023/1001734 3 Ordinance No. 686U Page 9 of 12 to alleviate artesian water pressure underground and to intercept water, preventing it from recharging underground water, 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 Remediation Project is anticipated to cost $33 million. The City sought and qualified for a grant in the amount of $23.3 million from the Federal Emergency Management Agency, and received a $5 million commitment from LA County Board Supervisor Janice Hahn. The City is currently seeking additional sources of funds. Since then, the land movement has accelerated and the City Council directed that two of the five planned hydraugers from the Remediation Project be installed on an emergency basis (the Emergency Hydraugers Project), appropriating almost $10 million of the City's funds. As part of the preparation, the City drilled a number of boreholes to obtain additional information to determine the ideal placement of the Emergency Hydraugers. As a result of the data collected from the boreholes, the City determined that the Emergency Hydraugers Project is not likely to be successful at this time: the Project was designed to remove water from a slip plane approximately 150 feet below the surface, to relieve artesian pressure; but the boreholes revealed that the majority of the land movement is due to a second slip plane, which has not previously moved, that is located about 330 feet below the surface. The hydraugers cannot reach this slip plane. The City is currently investigating other methods to remediate the landslide, the primary of which being addressing the Landslide Complex holistically, working in concert with ACLAD, KCHAD, and hopefully the City of Rolling Hills. The first step will be to drill a number of dewatering wells directly to the lower slip plane to relieve the artesian pressure as quickly as possible. The dewatering wells will likely sheer off within weeks and have to be redrilled until the land movement slows. The City will continue to seek solutions to remediate the land movement. SECTION 6. Consistency with the General Plan The City Council finds that this Ordinance is consistent with the following goals and policies of the City's General Plan. Circulation Element Policies — GP Page C-7 30. Discourage the installation or extension of any infrastructure component into any area known to be hazardous unless appropriate liability safeguards (such as geological hazard abatement districts) are in place and adequate mitigation measures are incorporated into the design. 31. Allow new development only where adequate infrastructure systems can reasonably be provided. Conservation and Open Space Element Policies — GP Page COS-4 01203 0023/1001734 3 Ordinance No 686U Page 10 of 12 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 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. 01203 0023/1001734 3 Ordinance No. 686U Page 11 of 12 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 12 months following the date of its adoption. 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 September, 2024, by a 4/5 vote of the entire City Council. Jo n iksh nk, Mayor ATTEST: CTeresa kaoka, 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. 686U was duly and regularly adopted by the City Council of said City at a regular meeting thereof held on September 3, 2024 by the following vote: AYES: Alegria, Bradley, Ferraro, Seo and Mayor Cruikshank NOES: None ABSENT: None ABSTAINED:None `Mity Clerk 01203 0023/1001734 3 Ordinance No 686U Page 12 of 12 ORDINANCE NO. 686U EXHIBIT A PORTUGUESE BEND LANDSLIDE COMPLEX Ordinance No. 686U Exhibit A Page 1 of 1 ORDINANCE NO. 686U EXHIBIT B HCD APPROVAL LETTER November 6, 2023 OrdInance No. 686U Exhibit B Page 1 of 4 STATE OF CALIFORNIA - BUSINESS, CONSUMER SERVICES AND HOUSING AGENCY GAVIN NEWSOM, Governor DEPARTMENT OF HOUSING AND COMMUNITY DEVELOPMENT DIVISION OF HOUSING POLICY DEVELOPMENT 2020 W. El Camino Avenue, Suite 500 Sacramento, CA 95833 (916) 263-2911 / FAX (916) 263-7453 www.hcd.ca.gov November 6, 2023 Brandy Forbes, Director Community Development Department City of Rancho Palos Verdes 30940 Hawthorne Blvd. Rancho Palos Verdes, CA 90275 Dear Brandy Forbes: RE: Approval of Urgency Ordinance – Moratorium on Construction within the Greater Portuguese Bend Landslide Complex The purpose of this letter is to provide a determination to the City of Rancho Palos Verdes (City) regarding the request to approve the adoption of Interim Urgency Ordinance No. 674U (Ordinance), prohibiting any construction within the geographic boundaries of the Greater Portuguese Bend Landslide Complex (Landslide Complex). The California Department of Housing and Community Development (HCD) is statutorily required to provide determination regarding proposed moratoria (Gov. Code, §66300, subd. (b)(1)(B)(ii)). HCD received a request for approval for the proposed Ordinance, met with the City staff, and reviewed relevant materials (e.g., staff letter, resolution declaring a local emergency, Interim Ordinance No. 674U, land movement monitoring surveys, etc.). Upon review of the written materials and discussion with the local jurisdiction, HCD has determined that the current conditions of the Landslide Complex pose an imminent threat to the health and safety of persons residing in the area subject to the Ordinance. Background Since the 1950s to 1970s, three large landslides have been active in the City, including Portuguese Bend Landslide (PBL), Abalone Cove Landslide (ACL), and the Klondike Canyon Landslide (KCL). The Greater Portuguese Bend Landslide Complex or Landslide Complex encompasses these three active landslides. Beginning in May of 2023, land movement has increased in the PBL and KCL complexes. Based on a surveying report of PBL in October 2022 and revised assessment in June 2023, “movement velocities have accelerated over the average velocity for the previous four years, which saw an acceleration over the previous 15-20 years”.1 The accelerating 1 McGee Surveying Consulting, Conditions Assessment Report, dated October 19, 2022 and revised June 6, 2023, Page 2. OrdInance No. 686U Exhibit B Page 2 of 4 land movement has destroyed homes, impacted the Portuguese Bend Reserve, increased water main breaks, and caused roadway and utility line distress. The City established Landslide Moratorium Area in 1978, imposing development restrictions in response to the Landslide Complex. Since then, the City has adopted a series of Interim Urgency Ordinances (Nos. 108U, 139U, 427U, 459U, 526, etc.) to temporarily halt permit processing and construction, and make amendments to enforce appropriate landslide mitigations measures in designated areas (Rancho Palos Verdes Municipal Code sections 15.20.040 and 15.20.050). The proposed Ordinance No. 674U is to encompass the entire Portuguese Bend Landslide Complex (including ACL and KCL). The Ordinance would address an imminent threat to public health and safety and prevent the exacerbation of existing unstable geologic conditions caused by activities related to new construction within the Landslide Complex. During the effective period of this Ordinance, the City will not accept or consider any permit applications, nor issue any permits for construction on any property within the Landslide Complex. This Ordinance also applies to any pending applications and to any permits or entitlements that have issued but upon which construction has not commenced. The City has confirmed that no sites included in its housing element site inventory are within the Landslide Complex. As a result, no such sites are subject to the proposed Ordinance. Pursuant to Government Code section 65858, the City seeks to adopt and enforce the proposed Ordinance that will begin with a 45-day period, following its date of adoption, and if necessary extended for up to 22 months and 15 days. The City is in the process of implementing a large-scale remediation project to stabilize the Landslide Complex. The project will proceed in three phases: (1) repairing existing fractures, (2) improving surface drainage of stormwater, and (3) installing a network of hydraugers. Staff anticipates that 90 percent of the planning and Environmental Impact Report certification will be complete by September 2024, and final engineering and permitting will be complete by September 2025. Local Moratorium Regulations Under the Housing Crisis Act (HCA) Pursuant to Government Code section 66300, subdivision (b)(1)(B)(ii), a city cannot enforce a moratorium that would limit housing development until it has submitted the ordinance to and received approval from HCD. Conditions for imposing a moratorium, or similar restrictions on housing development, must demonstrate “an imminent threat to the health and safety of persons residing in, or within the immediate vicinity of, the area subject to the moratorium” (Gov. Code, § 66300, subd. (b)(1)(B)(i)). OrdInance No. 686U Exhibit B Page 3 of 4 HCD acknowledges the severity of the Portuguese Bend Landslide Complex’s condition and the potential harm to public health and safety, and the environment, and anticipates that the Ordinance will need to be extended beyond the 45-day period, pursuant to Government Code section 65858. HCD hereby approves the adoption and enforcement of Interim Urgency Ordinance No. 674U during the effective period of 45 days from its adoption and its planned extension for up to 22 months and 15 days by the City of Rancho Palos Verdes. Conclusion In summary, HCD approves the adoption and enforcement of the Ordinance and hopes for a speedy resolution of this matter. If you have any questions regarding the content of this letter or would like additional technical assistance, please contact Mehrsa Imani, of our staff, at mehrsa.imani@hcd.ca.gov. Sincerely, Shannan West Housing Accountability Unit Chief OrdInance No. 686U Exhibit B Page 4 of 4 ORDINANCE NO. 686U EXHIBIT C McGee Survey Report Ordinance No. 686U Exhibit C Page 1 of 18 Portuguese Bend Land Movement Monitoring Survey October 10, 2023 (M38) through August 1, 2024 (M44) Survey Report for the City of Rancho Palos Verdes prepared by McGee Surveying Consulting Dated: October 30, 2023 with subsequent updates through August 1, 2024 Portuguese Bend is typically monitored for land movement on a tri-annual basis with an 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 Winter and Partial Spring Monitoring Surveys of 30-40 points. In past years, the survey report was published following the spring survey; however, at the City’s request, due to the excessive land movement, the surveys have been conducted every six weeks and now every month as listed below. The surveys are reported as Addendums with appropriate edits herein and the movement results included in the attached “PB MOVEMENT DATA POSTING…..xlsx” made available usually within five days of completion of the field survey. Movements are reported for the average date of the survey noted below and listed hereafter. M38 Full Survey - October 10, 2023 M39 Full Survey - January 13, 2024 M40 Partial Survey - March 8, 2024 M41 Partial Survey - April 17, 2024 M42 Full Survey - May 28, 2024 M44 Full Survey - August 1, 2024 SPREADSHEET ATTACHMENT: “PB MOVEMENT DATA POSTING M44 - 2007 to August 1, 2024.xlsx” OVERVIEW: GNSS MONITORING NETWORK (M38) McGee Surveying Consulting (MSC) performed the 2023-2024 land movement monitoring surveys at Portuguese Bend. The surveys were planned, coordinated, and executed by Michael McGee, PLS3945 of MSC who is responsible for the field surveys, processing observations, network adjustments, analysis, and reports. For a general history, details and procedures utilized in this survey but not re-stated here, see the “Portuguese Bend Land Movement 2020-2021 Monitoring Survey” report dated October 5, 2021, revised and published May 11, 2022. See also prior reports. This Initial October 10, 2023 Survey determined the precise positions of 79 monitoring and control points. PVE3 and other CSRC CGPS (CGNSS) stations were used to support and reference the survey network and verify the recovery of the reference frame. This survey included two new points set in July 2023 for the M37 Survey in Klondike Canyon (Seaview) and ten new points set in September 2023. Additional points have been set on most subsequent surveys as necessary and noted in the addendums. Point KC02 was replaced by KC24 in the October in anticipation of its future destruction. Point AB21 was recovered from the 2007 survey and substituted for nearby AB20 (destroyed by others) and will facilitated continuous monitoring at this location. B-1Ordinance No. 686U Exhibit C Page 2 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 2 of 17 The movements of new points are included in this Report as an Addendums. All monitoring survey coordinates and movements to date are listed in the spreadsheet “PB MOVEMENT DATA POSTING 2007-[present].xlsx” noted above as attached to this Report. PROJECT DATUMS - REFERENCE FRAME 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. Although more current epoch adjustments are available (e.g. NAD83 (2011) Epoch 2010.00), Epoch 2007.00 is retained to maintain consistently relative positions over time. Orthometric heights (NAVD88 Elevations) are based on measured ellipsoid heights combined with the NGS Geoid03 model and referenced to NGS Benchmarks. Although more current geoid models (e.g. Geoid18), are available, Geoid03 is retained to maintain consistently relative height movements over time as explained in said May 2022 Report. The latitudes and longitudes determined by GNSS measurements are converted to grid coordinates by projected onto NAD83 California State Plane Coordinates Zone 5 in US Survey Feet. A valid recovery of the survey reference frame is essential to accurately measure and assess actual movements of individual points relative to the greater peninsula. The method for recovering the monitoring survey reference frame was modified in 2019 to improve the efficiency and simplify the processing and analysis of the monitoring surveys. Since 2007, Point AB02 (at the south end of Portuguese Point) has proven to be stable relative to PVE3 which is a California Spatial Reference Center (CSRC) Continuously Operated GPS Station (CGPS) at City Hall. The present procedure fixes PVE3RP (a PK Nail set on the concrete base of PVE3 as a reference mark to PVE3) and checking to point AB02. The proven positions relative to PVE3 are listed below. Pt# Latitude Longitude NAVD88 Ht Source) AB02 33-44-13.84878 118-22-26.19243 116.47 ft 2007 - October 2018 position PVE3RP 33-44-35.74239 118-24-15.27451 346.88 ft Average of 5 years referencing to PVE3 Comparing the positions of AB02 on Portuguese Point with PVE3RP at City Hall and other CSRC CGPS Stations provides a redundant verification that the reference frame is stable and successfully recovered for each monitoring survey. An additional stable check point “RP01” was established near the entrance to the Trump Golf Course for incorporation in future surveys. The rate of movement (velocities) of the land masses have increased over the past five years compared to the previous 12-year average. See “Assessment of Movements & Accelerations” addressed on Page 11. Notwithstanding the 2019 monitoring process noted above, the processing of observations was necessarily modified for this fall survey because of the higher velocities as follows. The October 2023 observations were processed as follows. The Base Station at AB73 was occupied over a six- day period and was found to have moved about 0.016 feet per day similar to other monitoring points in the area. To determine accurate positions and therefore precision movements it was necessary to determine a daily position of AB73. This was accomplished by processing the static data collected each day at AB73 with static data downloaded from the CSRC for CGPS stations PVE3 and PVHS. PVE3 is and has always been the basic constraint for the monitoring survey’s reference frame. PVHS was used to verify the stability of PVE3. Subsequently positions of AB73 were computed for each day referenced to PVE3. The identity for processing the daily observations of AB73 and related RTK measurements was to assign to AB73 the identity of AB731, AB732, AB733, AB734 & AB735 for days 1 through 5 occurring on October 8, 9, 10, 11 & 13. BASE STATIONS – POINT NAMES AB61 and AB20 have previously served as suitable GNSS Base Stations for referencing measured positions of the monitoring points. AB61 is no longer accessed due to its environmental sensitivity and lack of security. AB73, located on the US Pony Club property was utilized as the Base Station up to the October 2023 survey. Access was obtained unilaterally by MSC from the Pony Club manager for exclusive permission to enter the property confirmed prior to each survey entry with the understanding that 5 mph driving protocols are observed. Point AB73 was not a planned monitoring point but given the increased rates of movement, it fills in a gap between AB20 and AB50 and moves consistent with AB20. AB50 and AB73 are on the south and north sides of B-2Ordinance No. 686U Exhibit C Page 3 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 3 of 17 PVDS respectively. The separation between AB73 and AB50 is diminishing at the rate of about one foot per month in April 2024 resulting in a steeper slope on the north side of PVDS which may be de-stabilizing. Due to the continuously increasing velocities of land movement, the present on-site base stations (AB20 and AB73) are no longer stable for measuring relative movements. In the January 2024 survey the Smartnet RTN network utilizing remote base stations connected by the Internet was used to measure positions and vectors which were re-referenced to PVE3RP and PVE3 in a network least squares adjustment. Surveys subsequent to the January survey are referenced to a new base station monument “RP02” set about 1400 feet northerly of the entrance to Abalone Cove Park and ¼ mile westerly of the present active slide boundary. See discussion hereafter. October 2023 GNSS Survey Monitoring Points Network The monitoring points names were established in the early surveys. The points are named for the slide they fall within and given a number. For example, AB01, PB01, KC01, CR01 and FT01. The number is increased as new points are established to replace abandoned or destroyed points or expand the network. Many of the original points are lost or no longer monitored. For data management purposes the point names are also prefixed with a sequential monitoring number to distinguish subsequent surveys. For example, for the occupation of AB02 on the 16th monitoring survey, AB02 is called M16AB02 where M16 indicates the sequence number since the first Monitoring Survey “M01” in September 2007. The prefix is stripped in these Reports. B-3Ordinance No. 686U Exhibit C Page 4 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 4 of 17 GNSS October 2023 M38 Survey Parameters, Metadata & Equipment Date of Annual Initial Survey: M38 – October 10, 2023 (mean date) between 0800-1700 PDST (+7 hrs for UTC). Constellations: GPS (31 Satellites), Russian GLONASS (23 Satellites), Galileo (23 Satellites) and Beidue (40 Satellites). Observables (Carrier Waves): GPS (L1, L2, L5), GLONASS (L1, L2), Beidue (L1, L2); & Galileo (4 Carrier Waves) Data Epoch Rate - 0.2 seconds (20HZ) at the GS18 Rover; 1 second at the GS18 Base Satellites: 20-40; GDOP: < 2; Elevation Mask: 0° at the Rover and Base Station Ephemeris: Broadcast for RTK vectors. Weather: Mostly calm clear skies, temperature 65-75° F, no significant weather. Space Weather: Boulder K Index 1-3 averaging 2 (gauges ionospheric activity on a scale of 0-9; less than 6 preferred) Equipment: GNSS Base Receiver Unit No. M11, Operator: M. McGee, PLS; Occupied Base Station Receiver Make & Model: Leica GS18 with integrated Antenna; Mount: Tripod & Tribrach GNSS Rover Receiver Unit No. M10, Operator: M. McGee, PLS Receiver Make & Model: Leica GS18T with integrated Antenna; Mount: Fixed Height Pole #4 Processing & Adjustments: Leica Infinity v4.0 and "Starnet-PRO” version 11.0.6 Software Prior to 2019, geodetic grade GNSS receivers collected static satellite signal data for post processing. The instrumentation was upgraded in 2020 to a Leica GS18 Base with a GS18T RTK Rover operating in real-time with an FM radio system which utilizes the latest technology to deliver increased productivity and precision of point positions. The GS18 receiver incorporates an Inertial Measurement Unit and tracks four Global Navigation Satellite Systems (GNSS): 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 usually obtained with some exceptions. Experience has shown the independent measurements generally agree on average about 0.02 feet when referenced to a local base receiver. ADJUSTMENTS & ANALYSIS Network Adjustment: A minimally constrained adjustment is utilized to develop NAD83 (2007) 2007.00 Epoch Zone 5 State Plane Coordinates and NAVD88 Heights of the monitoring points. The NAVD88 orthometric heights (elevations) are determined by combining the measured ellipsoid heights with the Geoid 03 Model. Previously, Point AB02 was fixed, and the stability verified relative to PVE3RP which is 1.5 to 3 miles westerly and outside the influence of the land movements. AB02 is expected to be stable and unaffected by the land movement; however, due to the substantially increased rates of movement resulting in dynamically differential movements the process was modified as noted above to assure accurate positions. This was accomplished by computing daily positions on the Base Station AB73 (AB731, AB732, AB733, AB734, AB735) relative to the reference frame fixed at station PVE3 noted above. Listed here are the differences. Differences in Feet ID dN dE dZ_ PVE3 0.000 0.000 Fixed Horizontal, CGPS Station at City Hall AB02 -0.022 -0.008 0.000 Fixed Elevation & Horizontal Check PVE3RP -0.010 -0.003 -0.055 Closure Check from PVE3 to AB73 to PVE3RP at City Hall PVHS -0.035 0.003 Horizontal Check on CGPS Station 2 Miles North of PB Comments: Fixing the CGPS station PVE3 (fixed constraint since 2007) finds the differences at PVHS, PVE3RP and AB02 are insignificant measurement noise. Given that AB02, PVE3RP, PVE3 and PVHS are in good relative agreement, the survey reference frame is deemed stable and successfully recovered from which local land movements were determined. ACCURACY STATEMENTS Vector Residuals: In this Initial Survey, the two-dimensional vector residuals averaged 0.012 feet and the absolute value of the vertical residuals averaged 0.02 feet as listed below. The vector residuals are based on a network adjustment of independent point positions. Vector Lengths(ft) Two Dimensional Residuals Absolute Vertical Residuals Vary Average Average Std.Dev. Maximum Average Std.Dev. _ Range 131-16391 3792 0.012 0.006 0.029 0.02 0.02 -0.03 to +0.08 B-4Ordinance No. 686U Exhibit C Page 5 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 5 of 17 Movement Accuracy: A point is deemed to have moved if, at the 95% level of confidence the horizontal movement (signal) of a point between two epochs is greater than the 95% Error (noise). Based on multiple independent occupations, the horizontal (2D) movements reported between October 2022 (M34) and October 2023 (M38) statistically attained a relative average accuracy of 0.014 feet at the 95% Level of Confidence with a Standard Deviation of 0.004 feet and a Range of 0.01 to 0.03 feet. See the attached file “PB MOVEMENT DATA POSTING …..xlsx” for movements and coordinates. Table of 2D & Vertical Movements for 12.0 Months October 10, 2022 (M34) & October 10, 2023 (M38) Listed below are the movement Azimuths (directions clockwise from North) in degrees, the two-dimensional horizontal movements, and the vertical (elevation) changes during the period in US Survey Feet. See the attached spreadsheet “PB MOVEMENT DATA POSTING…..xlsx”. Note: The horizontal measured movement confidence is estimated at +/-0.02’ (1/4”); therefore, movements of less than 0.03’ are statistically indeterminate. The estimated vertical measured movement confidence is +/-0.05’. * = Control Point for Recovery of the Reference Frame. Point ID Azimuth° Horizontal Movement Vertical Movement Point ID Azimuth° Horizontal Movement Vertical Movement AB01 244 0.06 0.0 KC02 196 1.99 0.1 AB02 201 0.02 0.0 KC05 219 0.88 -0.1 AB04 223 4.80 -0.6 KC06 253 1.34 -0.5 AB05 231 3.51 -0.6 KC07 256 0.02 0.0 AB13 198 2.48 -0.6 KC13 193 0.70 0.1 AB16 191 1.20 0.0 KC14 259 0.12 -0.1 AB17 187 0.06 0.0 KC15 233 1.36 -0.4 AB20 199 3.06 -0.1 KC16 251 0.03 0.0 AB24 198 2.68 0.0 KC17 222 1.24 -0.3 AB50 236 1.99 0.2 KC18 202 2.86 -0.3 AB51 202 2.05 -0.2 PB04 203 3.62 -0.3 AB53 192 2.75 -0.4 PB06 200 3.35 -0.3 AB57 169 2.37 -0.7 PB07 201 3.85 -0.1 AB58 183 2.22 -0.4 PB08 201 3.61 0.0 AB59 186 3.17 -0.8 PB09 198 3.49 -0.1 AB60 204 2.69 -0.3 PB12 200 4.67 -0.3 AB62 203 3.73 -0.4 PB13 201 3.83 0.1 AB63 207 3.58 -0.9 PB18 187 3.51 -0.5 AB64 155 0.35 -0.1 PB20 199 4.23 -0.4 AB65 167 1.49 -0.3 PB21 195 3.93 -0.6 AB66 196 2.29 -0.5 PB26 192 3.94 -0.4 AB67 180 1.12 -0.2 PB27 195 4.18 -0.8 AB68 193 2.03 -0.6 PB29 200 4.02 -1.0 AB70 203 2.97 -0.1 PB54 196 3.39 -0.2 AB71 158 1.76 -0.6 PB55 199 3.86 -0.8 AB73 203 3.00 -0.3 PB59 199 4.11 -0.6 CR07 171 1.87 -1.6 PB67 194 5.93 -0.8 CR50 225 0.11 -0.1 PB68 202 3.49 -0.1 CR51 223 0.08 0.0 PB69 202 3.91 -0.3 CR53 231 0.21 0.0 PB70 207 3.58 -0.8 FT06 192 3.66 -1.7 PB71 198 3.65 -0.4 FT08 257 0.06 0.0 UB02 189 4.17 0.3 FT09 271 0.08 -0.1 *PVE3RP 195 0.01 0.0 B-5Ordinance No. 686U Exhibit C Page 6 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 6 of 17 October 10, 2022 to October 10, 2023 Movement Distances (Feet) & Directions as Indicated Note: Distances are exaggerated x 100 for viewing Enlargement (PVDS) Enlargement (Seaview) B-6Ordinance No. 686U Exhibit C Page 7 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 7 of 17 MONITORING POINT MONUMENT NOTES & STATUS See the May 2022 Survey Report for prior monument notes. 2023: 16 points added to the monitoring program as listed below. AB20 destroyed after October 2023 Survey and replaced by AB21. MONITORING POINT MONUMENT DESCRIPTIONS All other Point Descriptions are listed in prior Reports. California State Plane Coordinates Zone 5 in the NAD83 (2007) Epoch 2007.00 and NAVD88 Datums are listed in the attached spreadsheet file “PB MOVEMENT DATA POSTING….”. Point Description Points added in July and October 2023 AB21 2" Punched GIP in “Cable Box”, Replaced AB20 after Oct. 2023 survey PB72 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete PB73 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete PB74 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete PB75 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete CR54 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete CW05 Found ½” x 48” Punched Rebar in Concrete Collar set June 2022 for CalWater CW06 Found ½” x 48” Punched Rebar in Concrete Collar set June 2022 for CalWater CW07 Found ½” x 48” Punched Rebar in Concrete Collar set June 2022 for CalWater CW08 Found 2” Mag nail in Concrete Base of 3’ Bollard set June 2022 for CalWater KC19 2” Mag Nail Drilled in a Concrete Curb on South side of Dauntless Dr. KC20 2” Mag Nail Drilled in a Concrete Curb on West side of Excelsior Dr. KC21 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete KC22 2" mag nail & washer in conc. in 2"x 24" GIP Collared in Concrete KC23 2” Mag Nail Drilled in a Concrete Curb on South side of Admirable Dr. KC24 2” Mag Nail Drilled in the Southwest Corner of a Concrete Vault, KC02 planned replacement RP01 Check Point at Trump Golf Course established in July 2023 for verifying the recovery of a stabile reference frame. Point is the top open part of the “B” on the south side of the rim of a manhole on the south side of PVDS at Conqueror Dr. Addendum No. 1 Report Portuguese Bend Land Movement Monitoring Survey Early Winter Full Monitoring Survey No. M39 - January 13, 2024 A special Portuguese Bend Full Monitoring Surveys (M39) was requested by the City in January 2024. The average date of the survey is January 13, 2024, 3.1 months after the October 10, 2023 Initial Monitoring for 2023-2024 reported above. The M39 survey included 79 monitoring points representing the present full network. A central base station (usually occupying AB73) was not feasible due to the excessive rate of land movement and reliance was made on the remote Smartnet RTN Stations which resulted in a lesser accuracy. For this survey, this was not an issue since the signal (measured movement) was much greater than the noise of the measurements expected to be less than 0.05’. A typical minimally constrained adjustment, as described above for M38, was processed for M39 to develop NAD83 (2007) Epoch 2007.00 CA Zone 5 State Plane Coordinates and NAVD88 Heights. The horizontal (2D) vector residuals averaged 0.03 feet with a Standard Deviation of 0.02 feet. The absolute value of the vertical residuals averaged 0.04 feet with a Standard Deviation of 0.04 feet. At the 95% Level of Confidence, estimated accuracy of the horizontal (2D) movements is 0.05 feet. The adjustment fixed point PVE3RP (an indirect fix on PVE3) and checked to other points found to be stable. 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. The successful recovery of a stable reference frame (coordinate system) is confirmed. Differences in Feet ID dN dE dZ_ PVE3RP 0.00 0.00 0.00 Fixed Reference at City Hall AB02 0.01 0.01 -0.05 Check Point at Portuguese Point RP01 -0.01 0.01 0.05 Check Point at Trump Golf Course B-7Ordinance No. 686U Exhibit C Page 8 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 8 of 17 Table of 2D & Vertical Movements for 3.1 Months October 10, 2023 (M38) & January 13, 2024 (M39) Listed below are the movement Azimuths (directions clockwise from North) in degrees, the two-dimensional horizontal movements, and the vertical (elevation) changes during the period in US Survey Feet. See the attached spreadsheet “PB MOVEMENT DATA POSTING (Revised 012224) 2007-Jan2024.xlsx”. Note: The horizontal measured movement confidence is estimated at +/-0.04’ (1/2”); therefore, indicated movements of less than 0.05’ are statistically indeterminate. The estimated vertical measured movement confidence is +/-0.08’. * = Control Point for Recovery of the Reference Frame. Point ID Azimuth° Horizontal Movement Vertical Movement Point ID Azimuth° Horizontal Movement Vertical Movement AB01 23 0.01 -0.1 KC13 188 0.44 0.0 AB02 27 0.01 0.0 KC14 262 0.03 0.0 AB04 223 3.52 -0.4 KC15 233 0.91 -0.3 AB05 230 2.76 -0.4 KC16 88 0.02 0.0 AB13 195 2.44 -0.4 KC17 218 0.80 -0.3 AB16 190 1.71 -0.1 KC18 200 2.03 -0.3 AB17 118 0.03 0.0 KC19 269 0.74 -0.2 AB21 197 2.80 0.1 KC20 277 0.67 -0.2 AB24 195 2.71 0.0 KC21 92 0.04 0.0 AB50 234 1.63 0.0 KC22 255 1.07 -0.5 AB51 200 2.08 0.0 KC23 237 0.57 -0.3 AB53 190 2.79 -0.3 KC24 199 1.22 -0.1 AB57 170 1.77 -0.5 PB04 202 2.63 0.0 AB58 179 2.50 -0.4 PB06 200 2.43 -0.2 AB59 185 3.11 -0.8 PB07 201 2.62 0.0 AB60 204 2.54 -0.2 PB08 201 2.60 0.0 AB62 203 2.62 -0.3 PB09 197 2.40 -0.1 AB63 207 2.79 -0.8 PB12 199 3.16 -0.3 AB64 128 0.19 0.0 PB13 199 2.51 0.0 AB65 167 1.98 -0.6 PB18 185 2.94 -0.5 AB66 193 2.41 -0.4 PB20 198 2.82 -0.3 AB67 181 1.56 -0.3 PB21 194 2.66 -0.5 AB68 191 2.28 -0.4 PB26 193 2.65 -0.2 AB70 200 2.85 -0.2 PB27 196 2.75 -0.5 AB71 158 1.35 -0.4 PB29 200 2.60 -0.7 AB73 202 2.52 -0.1 PB54 192 2.90 0.0 CR07 164 1.47 -1.2 PB55 198 2.88 -0.5 CR50 37 0.04 0.0 PB59 200 2.86 -0.3 CR51 107 0.04 0.2 PB67 195 3.32 -0.3 CR53 180 0.02 0.1 PB68 202 2.57 0.0 CR54 185 2.81 -0.9 PB69 201 2.82 -0.1 CW05 185 0.02 0.1 PB70 204 2.72 -0.3 CW06 59 0.05 0.1 PB71 197 2.90 0.0 FT06 191 2.48 -1.1 PB72 206 2.73 0.3 FT09 148 0.02 0.2 PB73 190 2.49 -0.4 KC02 193 1.30 0.0 PB74 193 3.08 -0.4 KC05 215 0.55 0.0 PB75 193 2.89 -0.1 KC06 256 0.94 -0.4 UB02 189 2.74 0.2 KC07 135 0.01 0.0 *PVE3RP 0 0 0.1 B-8Ordinance No. 686U Exhibit C Page 9 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 9 of 17 October 10, 2023 to January 13, 2024 Movement Distances (Feet) & Directions as Indicated Note: Movement distances exaggerated 100x for viewing Enlargement (PVDS) Enlargement (Seaview ) B-9Ordinance No. 686U Exhibit C Page 10 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 10 of 17 ASSESSMENT of MOVEMENT VELOCITIES & ACCELERATIONS 2014 to 2024 Others performed monitoring surveys of the Portuguese Bend land movement between 1994 and 2006. McGee Surveying Consulting assumed responsibility and defensibility for the Portuguese Bend Monitoring Program in 2007. The annual measured movements between 2007 and 2018 were fairly small and stable as shown below by the averages and maximums of a sampling of points for the 2014-2018 period. The fall 2019 monitoring survey found the annual rate of movements (velocities) increased (accelerated) about 4 to 6 times and remained stable for the next four years through 2022. A “year” here is defined as the 12-month period beginning with the rainy season on October 1st. Annual Average Movements in Feet, Maximum Movements & Change in the Average of a Sample of Points 2014-2018(4 Yrs) 2018-2022(4 Yrs) Change in ID Average Max. Average Max.__ _ Average AB20 0.09 0.20 0.48 0.54 +5X AB53 0.07 0.18 0.43 0.49 +6X AB68 0.05 0.11 0.31 0.32 +6X CR07 0.06 0.13 0.30 0.32 +5X KC06 0.04 0.09 0.16 0.22 +4X PB55 0.89 1.31 0.89 1.23 +1X (No Change) In the following twelve months between October 2022 and October 2023, the annual rate of movements were found to have again accelerated. The table below shows a sample of points within Abalone Cove (AB), Klondike Canyon (KC) and Portuguese Bend (PB). The left half of the table compares the annual movements and rate of movements per month for the October 2021 to October 2022 with the October 2022 to October 2023 period. The annual rate of movement for the sample averages in each slide increased about 6x for AB, 8x for KC and 5x for PB. In the same 12-month period between October 2022 and October 2023, accelerations were noted in the first seven months over the previous year and again in the last five months over the previous seven months as shown in the right half of the table below. The average rate of movement in each slide for these samples in the first seven months October 2022 through April 2023 increased about 3x for AB, 4x for KC and 2x for PB over the previous 12-month period of October 2021 to October 2022. The average rate of movements in each slide for the samples in the last five months May 2023 to October 2023 increased 4x for AB, 4x for KC and 3x for PB over the previous seven months. October 2021 to October 2023 Movements & Rates per Month (Feet) M32 > M34 (12 Mo.) M34 > M38 (12 Mo.) M34 > M36 (7 Mo.) M36 > M38 (5 Mo.) Point Oct '21 > Oct '22 Oct '22 > Oct '23 Oct '22 > May '23 May '22 > Oct '23 Movement Rate/Mo Movement Rate/Mo Movement Rate/Mo Movement Rate/Mo AB20 0.51 0.042 3.06 0.255 0.84 0.119 2.22 0.444 AB53 0.49 0.041 2.75 0.229 0.74 0.105 2.01 0.403 AB58 0.41 0.034 2.22 0.185 0.60 0.085 1.62 0.325 AB60 0.45 0.038 2.69 0.224 0.80 0.114 1.90 0.379 AB67 0.18 0.015 1.12 0.094 0.32 0.046 0.80 0.160 AB68 0.32 0.027 2.03 0.169 0.54 0.077 1.49 0.299 AB70 0.48 0.040 2.97 0.248 0.84 0.120 2.14 0.427 CR07 0.31 0.026 1.87 0.156 0.44 0.062 1.43 0.287 Av Move 0.39 0.033 2.34 0.195 0.64 0.091 1.70 0.340 KC06 0.16 0.014 1.34 0.111 0.33 0.047 1.01 0.202 KC13 0.09 0.007 0.70 0.058 0.19 0.027 0.51 0.102 KC17 0.14 0.012 1.24 0.104 0.31 0.044 0.93 0.187 Av Move 0.13 0.011 1.09 0.091 0.27 0.039 0.82 0.163 PB55 0.80 0.067 3.86 0.321 1.06 0.151 2.80 0.560 PB70 0.72 0.060 3.58 0.299 1.14 0.163 2.44 0.488 Av Move 0.76 0.063 3.72 0.310 1.10 0.157 2.62 0.524 B-10Ordinance No. 686U Exhibit C Page 11 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 11 of 17 Movement & Rate of Movement per Month In the last 3-month period October 10, 2023 to January 13, 2024, accelerations were noted again relative to the previous 12-months. The average rate of movements in each slide for the last 3-months for these samples increased about 4x for AB, 3x for KC and 3x for PB over the previous 12-month period of October 2022 to October 2023. RECOMMENDATION Continuity in the methods, precision and reporting of the monitoring surveys are necessary to evaluating results relative to and consistent with prior 2007-2024 monitoring survey campaigns. Monitoring survey campaigns require the services of an independent GNSS/Geodetic expert to evaluate and validate results to assure program integrity and defensibility. Maintaining a clearing of foliage in a 10’ radius around monitoring points and trimming nearby trees and brush above eye height is necessary to assure a clear view of the sky for tracking satellites. Satellites, although unseen, can appear anywhere in the sky above the horizon and the radio signals passing through foliage degrade the required survey accuracy and productivity. Presently, Points AB04, AB13, AB17, AB24, AB51, AB58, AB66, PB18, PB54, CR51 and CR53 have foliage obstructions limiting sky (satellite) visibility and require clearing prior to the next survey. Point M38 > M39 (3.1 Mo.) Oct. 10, 2023 to Jan. 13, 2024 Movement Rate/Mo AB20 2.80 0.903 AB53 2.79 0.900 AB58 2.50 0.806 AB60 2.54 0.819 AB67 1.56 0.503 AB68 2.28 0.735 AB70 2.85 0.919 CR07 1.47 0.474 Average 2.35 0.758 KC06 0.94 0.303 KC13 0.44 0.142 KC17 0.80 0.258 Average 0.73 0.236 PB55 2.88 0.929 PB70 2.72 0.877 Average 2.80 0.903 B-11Ordinance No. 686U Exhibit C Page 12 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 12 of 17 Addendum No. 2 Report Portuguese Bend Land Movement Monitoring Survey Partial Monitoring Survey No. M40 – March 8, 2024 This is the mid-winter Partial Monitoring Survey No. M40 Report. The average date of the survey is March 8, 2024, 1.8 months after the January 13, 2024 Full Monitoring Survey. The survey included 44 monitoring points and 3 reference control points. Occupying a central base station (usually AB73) was not feasible due to the excessive rate of land movement and reliance was made on the remote Smartnet RTN Stations which resulted in a lesser accuracy. For this survey, this was not an issue since the signal (measured movement) was much greater than the noise of the measurements expected to be about less than 0.05’. A typical minimally constrained network adjustment, as described above for survey M38, was processed for M40 to develop NAD83 (2007) Epoch 2007.00 CA Zone 5 State Plane Coordinates and NAVD88 Heights. The adjustment fixed point PVE3RP and checked to other points expected to be and found stable. 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_ PVE3RP 0.00 0.00 0.00 Fixed Reference at City Hall AB02 0.02 0.01 -0.09 Check Point on Portuguese Point RP01 0.00 0.02 -0.10 Check Point at Trump Golf Course The successful recovery of a stable horizontal reference frame confirmed. The Z height variations are attribted to the noise in the Smartnet Network solution. RP01 is intended to replace AB02. 2D Horizontal & Vertical Movements for 1.8 Months January 13, 2024 (M39) to March 8, 2024 (M40) The general rate of land movement increased significantly over the January 13, 2024 survey assessment. See the attached spreadsheet “PB MOVEMENT DATA POSTING…. .xlsx” for the movement Azimuths (directions clockwise from North) in degrees, the two-dimensional horizontal movements, and the vertical (elevation) changes during the period in US Survey Feet. See also the column for the rate of movement for each period annualized for an average month. Accuracy Statements The horizontal (2D) vector residuals averaged 0.04 feet with a Standard Deviation of 0.03 feet. The absolute value of the vertical residuals averaged 0.04 feet with a Standard Deviation of 0.03 feet. At the 95% Level of Confidence, the accuracy of the horizontal (2D) movements is estimated to be less than 0.04’. Movements of less than 0.05’ are statistically indeterminate. The estimated vertical measured movement confidence is 0.06’ to 0.09’. Addendum No. 3 Report Portuguese Bend Land Movement Monitoring Survey Partial Monitoring Survey No. M41 – April 17, 2024 This is the Spring Partial Monitoring Survey No. M41 Addendum Report. The field survey took place April 16- 18, 2024, average date of April 17, 2024, 1.35 months after the last March 8, 2024 Monitoring Survey. The survey included 55 monitoring points and 3 reference control points. Eleven new monitoring points were set and surveyed. The location of two new points were identified and will be surveyed on the next campaign in late May after the monuments are set by others. See the points descriptions below. B-12Ordinance No. 686U Exhibit C Page 13 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 13 of 17 Occupying previous base stations was not feasible due to the excessive rate of land movement. The Smartnet RTN Network does not require a base station but results in a somewhat lesser accuracy. Smartnet may be used in the future; however, it was deemed beneficial to establish a new base station outside the slide complex to facilitate future surveys. A new base station point “RP02” was set westerly of the slide complex and north of Abalone Cove Park. A typical minimally constrained adjustment, as described above for the M38 survey, was processed for M41 to develop NAD83 (2007) Epoch 2007.00 CA Zone 5 State Plane Coordinates and NAVD88 Heights. A least sqaures network adjustment was fixed at point PVE3RP to establish a position on the base at RP02 and thereby all other points in the survey. A check to RP01 easterluy outside the slide complex was made as noted below. This process will be the standard on future surveys. 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_ PVE3RP 0.00 0.00 0.00 Fixed Reference at City Hall RP01 -0.01 0.00 -0.03 Check Point at Trump Golf Course The successful recovery of a stable horizontal reference frame is confirmed. Point AB02 replaced by RP01, was used in previous surveys to also confirm recovery of the reference frame has limited access do to the slides. 2D Horizontal & Vertical Movements for 1.35 Months March 8, 2024 (M40) to April 17, 2024 (M41) The general rate of land movement increased significantly over the March survey. On average the velocities increased 76% with a maximum of 143%. Eight points doubled their velocities in the last six weeks over the previous eight weeks. In Abalone Cove and Portuguese Bend Slides many points are moving about three feet per month and in the Seaside Klondike Canyon Slide about ¾ of a foot per month. See the attached spreadsheet “PB MOVEMENT DATA POSTING…. .xlsx” for the movement Azimuths (directions clockwise from North) in degrees, the two-dimensional horizontal movements, and the vertical (elevation) changes during the period in US Survey Feet. See also the column for the rate of movement for each period annualized for an average month. Accuracy Statements The horizontal (2D) vector residuals averaged 0.04 feet with a Standard Deviation of 0.03 feet. The absolute value of the vertical residuals averaged 0.04 feet with a Standard Deviation of 0.03 feet. The land is moving 0.05’ to 0.10’ daily. Most points are measured a day apart resulting in large residuals but accurate positions of the mean coordinate. Therefore, it is at estimated the 95% Level of Confidence, the accuracy of the horizontal (2D) movements is estimated to be less than 0.03’. Movements of less than 0.04’ are statistically indeterminate. The estimated vertical measured movement confidence is 0.05’ to 0.10’. Monitoring Point Monument Descriptions See prior Reports for all other Point Descriptions. See the attached spreadsheet file “PB MOVEMENT DATA POSTING….” for California State Plane Coordinates Zone 5 in the NAD83 (2007) Epoch 2007.00 and NAVD88 Datums n Point Description of Points added in April 2024 AB74 8" Spike set as temporary monument to be replaced with a 2” GIP by others AB75 8" Spike set as temporary monument to be replaced with a 2” GIP by others AB76 8" Spike set as temporary monument to be replaced with a 2” GIP by others AB77 Location identified, 2” GIP to be set by others CR55 Set Mag Nail drilled in a Concrete walk/valley gutter CR56 Location identified, 2” GIP to be set by others KC25 Set Mag Nail drilled in a concrete & rock wall KC26 Set Mag Nail drilled in a concrete wall KC27 Set Mag Nail drilled in a concrete 6’ fire pit KC28 Set Mag Nail drilled in a concrete headwall KC29 Set Mag Nail drilled in a concrete headwall KC30 8" Spike set as temporary monument to be replaced with a 2” GIP by others KC31 8" Spike set as temporary monument to be replaced with a 2” GIP by others RP02 ½” x 4’ rebar in large sloping meadow with T-bar witness for new base station B-13Ordinance No. 686U Exhibit C Page 14 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 14 of 17 Addendum No. 4 Report Portuguese Bend Land Movement Monitoring Survey Full Monitoring Survey No. M42 – May 28, 2024 This is Full Monitoring Survey No. 42 Addendum Report. The field survey took place May 27-30, 2024, with an average date of May 28, 2024, 1.35 months after the last April 17, 2024 Partial Monitoring Survey. The survey included 93 monitoring points and 3 reference control points. Two new monitoring points (AB77 & CR56) were set and surveyed. Seven temporary monuments were reset with a permanent monument. Monuments CW01, CW07 and CW08, set in 2022 for CalWater, were adopted for the purpose of these surveys. See the point descriptions below. There are 14 monitoring points in the upper portion of the Reserve which are now difficult and time consuming to access due to the slides. An assistant provided by sub-contractor Chris Nelson & Associates (CNA) has been assigned these locations beginning with this May survey. CNA conducted their survey measurements with a Trimble R12 referenced to the Smartnet RTN for positioning. These monitoring point observations were referenced to the RPV Portuguese Bend network by way of connections to RP01, RP02 & PVE3RP. In the late June survey, CAN will be using Leica instrument similar to those used by McGee Surveying Consulting to assure the highest precision and increased productivity. A minimally constrained adjustment, as described above for the above M38 Survey Report, was processed for M42 to develop NAD83 (2007) Epoch 2007.00 CA Zone 5 State Plane Coordinates and NAVD88 Heights. A least sqaures network adjustment was fixed at point PVE3RP to establish a position on the base at RP02 and thereby all other points in the survey. A check to RP01 easterly outside the slide complex and other nearly stable points were made as noted below. Differences from the known fixed positions to the measured positions by this survey are listed here with their north, east and vertical components in feet. Differences in Feet ID dN dE dZ_ PVE3RP -0.00 -0.00 -0.00 Fixed Reference at City Hall RP01 -0.00 0.01 -0.01 RP02 -0.03 0.02 -0.01 AB02 0.00 -0.02 0.09 The successful recovery of a stable reference frame is confirmed. Point RP01 is intended to superseded AB02 used in previous surveys to confirm recovery of the reference frame. AB02 now has limited access do to the slides. Additionally, California Spatial Reference Center CGPS (Continous Operating GPS Stations) PVE3 and PVHS are incorporated from time to time to verify the stability of the refence frame. 2D Horizontal & Vertical Movements for 1.35 Months April 17, 2024 (M41) to May 28, 2024 (M42) The general rate of land movement increased in the last six weeks over the April survey. On average the velocities increased about 40% which is an increased rate of movement; however, the rate of acceleration is less than the estimated average of 76% in the previous six weeks. See the attached spreadsheet “PB MOVEMENT DATA POSTING…. .xlsx” for the movement Azimuths (directions clockwise from North) in degrees, the two- dimensional horizontal movements, and the vertical (elevation) changes during the period in US Survey Feet. See also the column for the rate of movement for each period annualized for an average 30.42-day month. Accuracy Statements The horizontal (2D) vector residuals are estimated at 0.02 feet with a Standard Deviation of 0.03 feet. The absolute value of the vertical residuals are estimated at 0.03 feet with a Standard Deviation of 0.04 feet. The rate of land movement varies and is as much as 0.12’ daily. It is estimated at the 95% Level of Confidence, the accuracy of the horizontal (2D) movements is estimated to be 0.04-0.06’. Movements less than the B-14Ordinance No. 686U Exhibit C Page 15 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 15 of 17 Confidence Interval are statistically indeterminate. The estimated vertical measured movement confidence is 0.05’ to 0.10’. Monitoring Point Monument Descriptions See prior Reports for all other Point Descriptions. See the attached spreadsheet file “PB MOVEMENT DATA POSTING….” for California State Plane Coordinates Zone 5 in the NAD83 (2007) Epoch 2007.00 and NAVD88 Datums n Addendum No. 5 Report Portuguese Bend Land Movement Monitoring Survey Full Monitoring Survey No. M43 – July 1, 2024 This is Full Monitoring Survey No. 43 Addendum Report. The field survey took place June 30, 2024 to July 3, 2024 with an average date taken as July 1, 2024, 1.12 months after the last May 28 Monitoring Survey. The survey included 93 monitoring points and 3 reference control points. 14 monitoring points in the upper portion of the Reserve require about three miles of hiking to access due to the slides. An assistant provided by sub-contractor Chris Nelson & Associates (CNA) is assigned these locations. A loaner GS18 Leica instrument same as used by McGee Surveying Consulting (MSC) and connected to MSC’s RTK base station is utilized to assure the highest precision and increased productivity. A minimally constrained adjustment, as described above for the above M38 Survey Report, was processed for M43 to develop NAD83 (2007) Epoch 2007.00 CA Zone 5 State Plane Coordinates and NAVD88 Heights. A least sqaures network adjustment was fixed at point PVE3RP to establish a position on the base at RP02 and thereby all points in the survey. A check to RP01 easterly outside the slide complex, AB02 and other nearly stable points were made as noted below. Differences from the known fixed positions to the measured positions by this survey are listed here with their north, east and vertical components in feet. Differences in Feet ID dN dE dZ_ PVE3RP -0.00 -0.00 -0.00 Fixed Reference at City Hall RP01 +0.01 -0.01 -0.00 RP02 -0.03 0.02 -0.01 AB02 -0.01 -0.02 +0.03 PVE3 +0.01 +0.00 -0.11 CSRC CGPS Station at City Hall Recovery and confirmation of a stable reference frame is essential to assess the actual movement of the monitoruing points. The diffeences listed above are at the noise level of the measurements confirming a successful recovery of the reference frame. Because AB02 has limited access do to the slides, Point RP01 is intended to suplement AB02 used in previous surveys to confirm recovery of the reference frame. Additionally, California Spatial Reference Center CGPS (Continous Operating GPS Stations) PVE3 and PVHS are incorporated to verify the stability and recovery of the refence frame. 2D Horizontal & Vertical Movements for 1.12 Months M42 to M43 The rate of land movement varies and averages about 3 feet per average month with a maximum of 4.88 feet. The general rate of land movement increased about 25% on average; however, the rate of acceleration is less as indicated by the estimated average increase of 41% in the rate of land movement in the previous month. See the attached spreadsheet “PB MOVEMENT DATA POSTING…. .xlsx” for the movement Azimuths (directions clockwise from North) in degrees, the two-dimensional horizontal movements, and the vertical (elevation) changes during the period in US Survey Feet. See also the column for the rate of movement for each period annualized for an average 30.42-day month. B-15Ordinance No. 686U Exhibit C Page 16 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 16 of 17 Accuracy Statements The horizontal (2D) vector residuals are estimated at 0.02 feet with a Standard Deviation of 0.03 feet. The absolute value of the vertical residuals are estimated at 0.03 feet with a Standard Deviation of 0.04 feet. It is estimated at the 95% Level of Confidence, the accuracy of the horizontal (2D) movements is estimated to be 0.04-0.06’. Movements less than the Confidence Interval are statistically indeterminate. The estimated vertical measured movement confidence is 0.05’ to 0.10’. Monitoring Point Monument Descriptions See prior Reports for Point Descriptions. See the attached spreadsheet file “PB MOVEMENT DATA POSTING….” for California State Plane Coordinates Zone 5 in the NAD83 (2007) Epoch 2007.00 and elevations in the NAVD88 Datum. Point Description: Update of Points set in April & May AB74 1/2” x 4’ rebar encased in concrete witnessed by a steel t-bar post AB75 1/2” x 4’ rebar encased in concrete witnessed by a steel t-bar post AB76 1/2” x 4’ rebar encased in concrete witnessed by a steel t-bar post AB77 1” x 24” GIP with cap “Control Point” encased in concrete witnessed by a steel t-bar post CR56 1” x 24” GIP with cap “Control Point” encased in concrete witnessed by a steel t-bar post CW07 ½” x 4’ punched rebar in concrete with T-bar witness post CW08 ½” x 4’ punched rebar in concrete with T-bar witness post KC30 1/2” x 4’ rebar encased in concrete witnessed by a steel t-bar post KC31 8” spike set between two steel posts in line with a string of boulders RP02 ½” x 4’ punched rebar in concrete in large sloping meadow witnessed by a steel T-bar post Addendum No. 6 Report Portuguese Bend Land Movement Monitoring Survey Full Monitoring Survey No. M44 – August 1, 2024 This is Full Monitoring Survey No. 44 Addendum Report. The field survey took place July 30, 2024 to August 3, 2024 with an average date taken as August 1, 2024, 1.02 months after the last July 1 Monitoring Survey. The survey included 98 monitoring points and 3 reference control points (RP01, RP02 & AB02). 15 monitoring points in the upper portion of the Reserve some requiring substantial hiking for access due to the slides. An assistant provided by sub-contractor Chris Nelson & Associates (CNA) is assigned these locations. A minimally constrained adjustment, as described above for the above M38 Survey Report, was processed for M44 to develop NAD83 (2007) Epoch 2007.00 CA Zone 5 State Plane Coordinates and NAVD88 Heights. A least sqaures network adjustment was fixed at point PVE3RP to verify and establish a position on the base station point RP02 and thereby all points in the survey. A check to RP01 easterly outside the slide complex, AB02 and other nearly stable points were made as noted below. Differences from the known fixed positions to the measured positions by this survey are listed here with their north, east and vertical components in feet. Differences in Feet ID dN dE dZ_ PVE3RP -0.00 -0.00 -0.00 Fixed Reference at City Hall RP01 0.03 -0.03 0.01 Check Point RP02 -0.00 0.01 0.07 Base Station AB02 -0.01 0.00 0.07 Check Point AB17 0.00 0.00 0.05 Point Historically Not Moving CW01 0.01 0.02 0.11 Point Historically Not Moving KC16 0.00 0.01 0.10 Point Historically Not Moving B-16Ordinance No. 686U Exhibit C Page 17 of 18 McGEE SURVEYING CONSULTING 5290 Overpass Road, Ste#107, Santa Barbara, CA 93111 Page 17 of 17 Recovery and confirmation of a stable reference frame is essential to assess the actual movement of the monitoruing points. The diffeences listed above are at the noise level of the measurements confirming a successful recovery of the reference frame. Because AB02 has limited access do to the slides, Point RP01 is intended to supplement AB02 used in previous surveys to confirm recovery of the reference frame. Additionally, California Spatial Reference Center CGPS (Continous Operating GPS Stations) PVE3 and PVHS are incorporated at times for additional verification of the stability and recovery of the refence frame. 2D Horizontal & Vertical Movements for 1.02 Months M43 to M44 The rate of land movement varies and averaged about 2.4 feet per average month in the last period with a maximum of 4.69 feet per month. The general rate (velocity) of land movement varied from about -13% to +13% and averaged nearly zero. See the attached spreadsheet “PB MOVEMENT DATA POSTING…. .xlsx” for the movement Azimuths (directions clockwise from North) in degrees, the two-dimensional horizontal movements, vertical (elevation) changes during the period in US Survey Feet. See also the column for the rate of movement for each period annualized for an average 30.42-day month. Accuracy Statements The horizontal (2D) vector residuals are estimated at 0.02 feet with a Standard Deviation of 0.03 feet. The absolute value of the vertical residuals are estimated at 0.03 feet with a Standard Deviation of 0.04 feet. It is estimated at the 95% Level of Confidence, the accuracy of the horizontal (2D) movements is estimated to be 0.04’. Movements less than the Confidence Interval are statistically indeterminate. The estimated vertical measured movement confidence is about 0.05’ to 0.10’. Monitoring Point Monument Descriptions See prior Reports for Point Descriptions. See the attached spreadsheet file “PB MOVEMENT DATA POSTING….” for California State Plane Coordinates Zone 5 in the NAD83 (2007) Epoch 2007.00 and elevations in the NAVD88 Datum. Point Description: Update of Points set in August AB78 2” Magnetic Nail drilled in a concrete curb on the N. side of Vanderlip Dr., replaced AB71 CR57 ½” x 4’ punched rebar in concrete with T-bar witness post, replaces CR07 KC34 2” Magnetic Nail set in Stalwart Dr. East of Schooner Dr. KC35 2” Magnetic Nail set in Xn of Schooner & Stalwart Dr. KC36 2” Magnetic Nail set in Xn of Schooner & Admirable Dr. KC37 Punch mark on north side Sewer MH in Admirable Dr. East of Schooner Dr. SURVEYOR'S STATEMENT The M38 Fall October 2023 Full Survey and subsequent 2024 Surveys and Addendum Reports on the procedures, criteria, and results of the City of Rancho Palos Verdes Portuguese Bend Land Movement Monitoring Surveys were prepared by me on October 30, 2023 and updated August 15, 2024 at the request of Ramzi Awwad, Director of Public Works for the City of Rancho Palos Verdes. B-17Ordinance No. 686U Exhibit C Page 18 of 18 ORDINANCE NO. 686U EXHIBIT D CSA REPORT April 26, 2024 Ordinance No. 686U Exhibit D Page 1 of 6 SC6163 1 CSA Project No. SC6163 MEMORANDUM TO: Ara Mihranian, City Manager CC: Ramzi Awwad, Public Works Director Elena Gerli, City Attorney Cory Linder, Director of Recreation and Parks Katie Lozano, Open Space Manager FROM: Michael Phipps, CEG 1832, Contract City Geologist RE: Update on Land Movement Conditions Within the Greater Portuguese Bend Landslide Complex, Rancho Palos Verdes DATE: April 26, 2024 _____________________________________________________________________________________________________________ The following information was prepared in response to the City’s request for an update on current land movement conditions, observations, and our activities over the past six weeks within the Greater Portuguese Bend Landslide Complex (Landslide Complex). The Landslide Complex encompasses four historically active landslide areas: the Portuguese Bend Landslide (PBL), the Abalone Cove Landslide (ACL), the Klondike Canyon Landslide (KCL), and the Beach Club Landslide (BCL). However, it also includes areas outside of the historical boundaries of those known landslides, predominantly uphill from the Portuguese Bend and Abalone Cove landslides, within the Ancient Portuguese Bend Landslide Complex as mapped by various agencies (i.e., U.S. Geological Survey, California Geological Survey) and other researchers. Activities: Since our presentation to the City Council on March 19, 2024, CSA staff have conducted the following activities: •Performed field mapping throughout the Landslide Complex, including areas within the Portuguese Bend, Filiorum, Forrestal, and Abalone Cove Reserves, and the Glass Parcel; •Participated in the weekly meeting of the RPV Landslide Complex Working Group; •Provided additional input to OSM staff and the PVPLC related to annual fuel modification, non- native brush removal and habitat restoration projects; •Analyzed GPS monitoring data and recommended installation of new monitoring points; •Compiled and reviewed rainfall data; •Presented information regarding the landslide at the April 17, 2024 Town Hall Meeting; •Peer reviewed the proposed E1/E2 hydrauger emergency measures, including online (Teams) meetings on April 11, 16 and 18 to convey preliminary comments; •Participated in twice-weekly status meeting regarding the proposed emergency measures; •Peer review of the proposed KCLAD 5-step plan (in progress) B-1Ordinance No. 686U Exhibit D Page 2 of 6 SC6163 2 Rainfall: Rainfall and the resulting runoff and infiltration into the Landslide Complex continues to adversely affect the landslide area, following a significantly wetter than average (193%) rainy season in 2022-23. The second wettest February (11.22 inches) in the 67-year history of the Rolling Hills Fire Station rain gauge was recorded, after which rainfall amounts moderated in the latter half of March and through April to date, with 3.28 inches of rain falling since March 15, 2024. The current season rainfall total is 23.01 inches, about 169% of the season average over the past 67 years (LACDPW Gauge 1011B at Rolling Hills Fire Station 56). Land Movement Data: CSA’s January 29, 2024 update memorandum noted that average land movement velocities within the Landslide Complex from October 10, 2023 to January 13, 2024 had accelerated by a factor of 3x to 4x compared to the previous 12-month (Oct 2022-Oct 2023) monitoring period. Our March 15, 2024 update memorandum noted that land movement velocities within the Landslide Complex had then accelerated an additional 1.3x to 2.2x through early March, compared to the movement velocities in the October 2023-January 2024 timeframe. This acceleration was noted to be greatest in the ACL (2.2x) and areas upslope of it in the Ancient Portuguese Bend Landslide (2.1x). The lowest acceleration (1.3x) was for points in the KCL. Preliminary GPS survey data prepared by McGee Surveying Consulting, covering the period March 8, 2024 to April 17, 2024, were recently reviewed and analyzed. Across the entire landslide complex, average land movement velocity has accelerated an additional 76% (1.76x) above the January-March 2024 velocity. Recent land movement rates are approximately 6 to 9 inches per week in the ACL, 5 to 9 inches per week in the PBL, and 1 to 4 inches per week in the KCL. The middle of the overall Landslide Complex is moving the fastest at >9 inches per week. This information is shown graphically on the attached Figure 1--GPS Monitoring Displacement Rate Contour Map. To provide a broader perspective timewise, average land movement velocities have increased 95x, 31x and 41x over November 2019 measurements, for the ACL, PBL and KCL, respectively. The entire active landslide complex (area of major land movement now evident at the ground surface) has expanded from 380 acres to 675 acres. This movement continues to manifest at the ground surface in the form of landslide scarps, fissures, grabens/sinkholes, tensional cracking, shear zones and thrust features. Due to the continued acceleration, the ground movement features have continued to enlarge, expand, widen, or grow depending on the type of feature and location. Incremental horizontal displacements with land movement vectors from October 2022 through April 17, 2024 are shown on the attached Figure 2—GPS Monitoring Displacement Map. Field Observations: Road conditions on Palos Verdes Drive South (PVDS) across the lower landslide complex continue to be adversely impacted due to differential rates of land movement currently ranging from about 5 to 8 inches per week. More surface expression of land movement is also evident but is still slowly developing along the eastern margin of the KCL on Exultant Drive, Admirable Drive, the PVDS frontage street, and the Dauntless Drive/Admirable Drive intersection in the Seaview neighborhood. We have observed rapidly deteriorating conditions on private roads, most notably Narcissa Drive, Cinnamon Lane, and Vanderlip Road which have been impacted by major fissures and formation of grabens, and Seawall Drive in the Portuguese Bend Beach Club which is being deformed by bulging/uplifting ground at the toe of the KCL. The beach area of the Portuguese Bend Beach Club appears to be undergoing significant uplift across a broad area. Beach School Trail (Road) continues to undergo deformation in the lower ACL area but remains passable to the Portuguese Bend Nursery School and L.A. County lifeguard station due to ongoing maintenance efforts. Movement of the B-2Ordinance No. 686U Exhibit D Page 3 of 6 SC6163 3 Landslide Complex overriding Portuguese Point south of PVDS has toppled a portion of the rock retaining wall adjacent to Olmsted Trail and is affecting authorized users of Olmsted Trail access to Abalone Cove. In summary, our findings continue to be that the PBL, ACL, KCL, and a large portion of the Ancient Portuguese Bend Landslide Complex above the historically mapped PBL, ACL and KCL boundaries is involved in significant active landslide movement moving at unprecedented rates, predominantly in response to two consecutive seasons of significantly above average rainfall. The land movement continues to adversely impact trails and open space areas, public and private roads, private property including hundreds of residences, and utility infrastructure. -o- Attachments: Figure 1-- GPS Monitoring Displacement Rate Contour Map Figure 2—GPS Monitoring Displacement Map B-3Ordinance No. 686U Exhibit D Page 4 of 6 No r t h No r t h 0 250 500 1000 (feet) PONY TRAIL PORTUGUESE BEND LANDSLIDE FLYING TRIANGLE LANDSLIDE KLONDIKE CANYON LANDSLIDE ABALONE COVE LANDSLIDE ABALONE COVE PORTUGUESE POINT INSPIRATION POINT SACRED COVE APPROXIMATE BOUNDARY OF ANCIENT PORTUGUESE BEND LANDSLIDE COMPLEX BURMA ROAD NARCISSA DRIVE SWEETBAY ROAD PALOS VERDES DRIVE SOUTH CREST ROAD EXPLANATION Limits of the Ancient Portuguese Bend Landslide Complex Limits of Historically Mapped Landslides 2023/2024 Landslide Mapping SEAVIEW TRACT Current Limits of Major Landslide Movement (March 2024) CURRENT LIMITS OF MAJOR LANDSLIDE MOVEMENT (MARCH 2024) GPS Monument Displacement Rate (March 8, 2024 to April 17, 2024) Displacement Vector Scale 1"= 8"/week AB04 7.47 AB13 8.53 AB16 6.09 AB17 0.03 AB21 9.13 AB50 5.16 AB51 7.27 AB57 5.60 AB58 9.09 AB59 9.68 AB60 8.54 AB62 6.63 AB64 0.34 AB65 7.17 AB67 5.76 AB68 7.86 AB70 9.66 AB71 3.58 AB73 8.07 CR07 3.37 CR50 0.19 CR53 0.26 CR54 8.55 KC06 2.05 KC07 0.08 KC15 2.00 KC17 1.78 KC20 1.62 KC22 2.20 KC23 1.25 KC24 2.80 PB04 8.13 PB08 7.34 PB13 5.94 PB18 9.14 PB26 6.56 PB55 8.16 PB67 8.82 PB69 8.32 PB70 8.43 PB71 9.32 PB72 8.51 PB73 7.08 PB75 8.76 RP01 0.06 KC18 4.60 5.0 5.0 2.0 3.0 4.0 4.0 6 . 0 6.0 6.0 6.0 7.0 7. 0 7.0 7.0 8.0 8 . 0 8.0 8.0 8.0 8 . 0 9.0 9.0 Minimum Rate (inch/week) 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 Maximum Rate (inch/week) 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 Color COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS RANCHO PALOS VERDES, CALIFORNIA SC6163 POS MP 1"=500' PROJECT NO. DATE April 26, 2024 SCALE APPROVED BY GEO/ENG BY GPS MONITORING DISPLACEMENT RATE CONTOUR MAP (4/17/24 DATA) FIGURE NO. 1 Abalone Cove, Portuguese Bend, Klondike Canyon Hillshade basemap produced from publicly available LiDAR: "2015 - 2016 LARIAC Lidar DEM: Los Angeles Region, CA"NOTES: 1)October 10, 2023 GPS monitoring data was unavailable for monuments AB21, CR54, CW05, CW06, KC19, KC20, KC21, KC22, KC23, KC24, PB72, PB73, PB74, PB75, and RP01. 2)January 13, 2024 GPS monitoring data was unavailable for monuments AB20 and FT08. 3)March 8, 2024 GPS monitoring data was unavailable for monuments AB01, AB04, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. 4)April 17, 2024 GPS monitoring data was unavailable for monuments AB01, AB02, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. KC18 estimated. B-4Ordinance No. 686U Exhibit D Page 5 of 6 No r t h No r t h 0 250 500 1000 (feet) PORTUGUESE BEND LANDSLIDE FLYING TRIANGLE LANDSLIDE KLONDIKE CANYON LANDSLIDE ABALONE COVE LANDSLIDE APPROXIMATE BOUNDARY OF ANCIENT PORTUGUESE BEND LANDSLIDE COMPLEX EXPLANATION Limits of the Ancient Portuguese Bend Landslide Complex Limits of Historically Mapped Landslides 2023/2024 Landslide Mapping Current Limits of Major Landslide Movement (March 2024) CURRENT LIMITS OF MAJOR LANDSLIDE MOVEMENT (MARCH 2024) GPS Monument Displacement (October 10, 2022 to October 10, 2023) Displacement Vector Scale 1"=5' GPS Monument Displacement (October 10, 2023 to January 13, 2024) Displacement Vector Scale 1"=5' GPS Monument Displacement (January 13, 2024 to March 8, 2024) Displacement Vector Scale 1"=5' AB01 AB02 AB04 AB05 AB13 AB16 AB17 AB20AB21 AB24 AB50 AB51 AB53 AB57 AB58 AB59 AB60 AB62 AB63 AB64 AB65 AB66 AB67 AB68 AB70 AB71 AB73 CR07 CR50 CR51 CR53 CR54 CW05 CW06 FT06 FT08 FT09 KC02 KC05 KC06 KC07 KC13 KC14 KC15 KC16 KC17 KC18 KC19 KC20 KC21KC22 KC23 KC24 PB04 PB06 PB07 PB08 PB09 PB12 PB13 PB18 PB20 PB21 PB26 PB27 PB29 PB54 PB55 PB59 PB67PB68 PB69PB70 PB71 PB72 PB73 PB74 PB75 UB02 RP01 GPS Monument Displacement (March 8, 2024 to April 17, 2024) Displacement Vector Scale 1"=5' 365 days 95 days 55 days 40 days COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS RANCHO PALOS VERDES, CALIFORNIA SC6163 POS MP 1"=500'PROJECT NO. DATEApril 26, 2024 SCALE APPROVED BY GEO/ENG BY GPS MONITORING DISPLACEMENT MAP FIGURE NO. 2 Abalone Cove, Portuguese Bend, Klondike Canyon Hillshade basemap produced from publicly available LiDAR: "2015 - 2016 LARIAC Lidar DEM: Los Angeles Region, CA"NOTES: 1) October 10, 2023 GPS monitoring data was unavailable for monuments AB21, CR54, CW05, CW06, KC19, KC20, KC21, KC22, KC23, KC24, PB72, PB73, PB74, PB75, and RP01. 2) January 13, 2024 GPS monitoring data was unavailable for monuments AB20 and FT08. 3) March 8, 2024 GPS monitoring data was unavailable for monuments AB01, AB04, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. 4) April 17, 2024 GPS monitoring data was unavailable for monuments AB01, AB02, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. B-5Ordinance No. 686U Exhibit D Page 6 of 6 ORDINANCE NO. 686U EXHIBIT E CSA GEO REPORT June 25, 2024 Ordinance No. 686U Exhibit E Page 1 of 7 SC6163 1 CSA Project No. SC6163 MEMORANDUM TO: Ara Mihranian, City Manager CC: Ramzi Awwad, Public Works Director Elena Gerli, City Attorney Cory Linder, Director of Recreation and Parks Katie Lozano, Open Space Manager FROM: Michael Phipps, CEG 1832, Contract City Geologist RE: Update on Land Movement Conditions Within the Greater Portuguese Bend Landslide Complex, Rancho Palos Verdes DATE: June 25, 2024 _____________________________________________________________________________________________________________ The following information was prepared in response to the City’s request for an update on current land movement conditions, observations, and our activities over the past six weeks within the Greater Portuguese Bend Landslide Complex (Landslide Complex). The Landslide Complex encompasses four historically active landslide areas: the Portuguese Bend Landslide (PBL), the Abalone Cove Landslide (ACL), the Klondike Canyon Landslide (KCL), and the Beach Club Landslide (BCL). However, it also includes areas outside of the historical boundaries of those known landslides, predominantly uphill from the Portuguese Bend and Abalone Cove landslides, within the Ancient Portuguese Bend Landslide Complex as mapped by various agencies (i.e., U.S. Geological Survey, California Geological Survey) and other researchers. Activities: Since our presentation to the City Council on May 7, 2024, CSA staff have conducted the following activities: • Performed field mapping throughout the Landslide Complex, including areas within the Portuguese Bend, Filiorum, Forrestal, and Abalone Cove Reserves, the Portuguese Bend Beach Club, the Portuguese Bend Community Association, the York Property, and areas within the Abalone Cove Landslide Abatement District (ACLAD) and Klondike Canyon Geological Hazard Abatement District (KCGHAD); • Participated in the weekly meeting of the RPV Landslide Complex Working Group; • Analyzed GPS monitoring data prepared by McGee Surveying Consulting, from April 17, 2024 and May 28, 2024 monitoring events; • Compiled and reviewed rainfall data; • Completed peer review of the proposed KCLAD 5-step plan; • Evaluated InSAR as a potential landslide monitoring tool; • Observed and logged (as a second party) Test Borings E-1-10, E-1-5A and E-1-5-S; • Reviewed requests for emergency grading and foundation repairs. B-1 ,.... <::oTTON, SHIRES AND AssOCIA TES, INC. --CONSULTING ENGINEERS AND GEOLOGISTS l,T I CrrY OF •~-RAN CHO PALOS VER DES Ordinance No. 686U Exhibit E Page 2 of 7 SC6163 2 Rainfall: The 2023-24 season rainfall and the resulting runoff and infiltration into the Landslide Complex continues to adversely affect the landslide area, following a significantly wetter than average (193%) rainy season in 2022-23. The current season rainfall total is 23.19 inches, about 170% of the season average over the past 67 years (LACDPW Gauge 1011B at Rolling Hills Fire Station 56). Only 0.18 inches of rain was recorded at this gauge since our last update on April 26, 2024. Land Movement Data: Recent GPS survey data published by McGee Surveying Consulting for the period April 17, 2024 through May 28, 2024 were reviewed and analyzed. As noted in previous updates (CSA, 12/12/23, 1/29/24, 3/8/24 and 4/26/24), land movement velocities calculated from GPS survey monitoring data have continued to accelerate throughout the Landslide Complex since October 2022. For the most recent 41-day monitoring period of April 17-May 28, 2024, average land movement velocity has accelerated an additional 41% (1.41x) above the March 8-April 17, 2024 monitoring period velocity. Recent land movement rates (velocities) are approximately 7 to 11 inches per week in the ACL, 9 to 12 inches per week in the PBL, and 2 to 7 inches per week in the KCL (with highest velocities in the western KCL occurring between Klondike Canyon and the eastern PBL boundary). The GPS monitoring data are presented graphically on attached Figures 1 through 3. Figure 1 presents scaled, incremental displacements and movement vectors since October 2022. Figure 2 presents scaled displacement rates (i.e., movement velocities) and vectors since October 2022. Figure 3 presents a contour map (aka “heat map”) of displacement rates for the current April 17-May 28, 2024 monitoring period. Of continued interest is that the middle of the overall Landslide Complex is moving the fastest at >13 inches per week. The velocity contours in the 12-13 inch/week range are generally west of the historical PBL boundary, and a large portion of the center of the overall Landslide Complex is moving at greater than 11 inches per week. This represents a significant and unprecedented change in movement behavior from historical movements of the PBL and ACL. The entire active Landslide Complex (area of major land movement now evident at the ground surface) has expanded from the combined historical boundaries of the ACL/PBL/KCL of about 380 acres, to an estimated 680 acres in size. Based upon our review of the current land movement data, field mapping of active landslide limits, recent boring information, as well as historical data from previous geotechnical investigations, there is growing evidence that landslide movement is occurring on multiple failure surfaces (i.e., “slide planes”) including movement on the historically modeled/structure-contoured failure surfaces of the ACL and PBL, as well as a deeper “ancient” landslide surface previously identified beneath the PBL (BYA/Ehlig, 1997; Leighton 1998, 2000, 2001). Field Observations: Landslide movement continues to manifest at the ground surface in the form of scarps, fissures, grabens/sinkholes, tensional cracking, shear zones and thrust features. Due to the continued acceleration of the landslide, the ground movement features have continued to enlarge, expand, widen, or grow depending on the type of feature and location. Based upon recent field mapping, the total area of the active Landslide Complex has expanded by approximately five acres including the following areas: • The eastern landslide boundary of the KCL is now manifesting approximately 50 feet farther east on Admirable Drive and 150 feet farther east on Exultant Drive; however, these boundaries B-2Ordinance No. 686U Exhibit E Page 3 of 7 SC6163 3 appear to be consistent with historical mapping of the KCL and the location of a pre- development drainage course that is believed to define the easterly limit of prehistoric landsliding. • The westerly boundary of the active Landslide Complex in the Abalone Cove Landslide area has expanded approximately 180 feet farther west at Narcissa Drive and on the York property at 6001 PV Drive South. This new expanded landslide movement is quickly deforming the Narcissa Drive curve and is the same movement that has displaced the administration building and caused major bulging of the parking lot at the Wayfarer’s Chapel property. • The Portuguese Bend Beach Club area continues to experience major deformation along Seawall Road and bulging/uplift on the order of 4 to 5 feet across the beach on an east-west trend. This deformation appears to continue offshore into the PBL based on major emergence of land in the surf zone and nearshore zone at the southeasterly toe of the PBL. In this area, the seafloor has uplifted above mean sea level approximately 200 to 300 feet south of the former foreshore slope of the beach. Road conditions on Palos Verdes Drive South (PVDS) across the lower landslide complex continue to be adversely impacted due to differential rates of land movement currently ranging from about 2 to 7 inches/week across the KCL, 8-12 inches per week across the PBL, and 5-10 inches per week across the ACL. Portuguese Point is being overridden by the landslide, resulting in failure of the historical rock wall along the Olmsted Trail and loss of beach access to Abalone Cove via Olmsted Trail. In summary, our findings continue to be that the PBL, ACL, KCL, and a large portion of the Ancient Portuguese Bend Landslide Complex outside of the historically mapped PBL, ACL and KCL boundaries is involved in significant active landslide movement moving at unprecedented rates, predominantly in response to two consecutive seasons of significantly above average rainfall. The land movement continues to severely impact trails and open space areas, public and private roads, private property including hundreds of residential structures, and utility infrastructure. -o- Attachments: Figure 1-- GPS Monitoring Displacement & Vector Map Figure 2—GPS Monitoring Displacement Rate & Vector Map Figure 3—GPS Monitoring Displacement Rate Contour Map (5/28/24 Data) B-3Ordinance No. 686U Exhibit E Page 4 of 7 0 250 500 1000 (feet) PONY TRAIL PORTUGUESE BEND LANDSLIDE FLYING TRIANGLE LANDSLIDE KLONDIKE CANYON LANDSLIDE ABALONE COVE LANDSLIDE ABALONE COVE PORTUGUESE POINT INSPIRATION POINT SACRED COVE APPROXIMATE BOUNDARY OF ANCIENT PORTUGUESE BEND LANDSLIDE COMPLEX BURMA ROAD NARCISSA DRIVE SWEETBAY ROAD PALOS VERDES DRIVE SOUTH CREST ROAD EXPLANATION Limits of the Ancient Portuguese Bend Landslide Complex Limits of Historically Mapped Landslides 2023/2024 Landslide Mapping SEAVIEW TRACT Current Limits of Major Landslide Movement (March 2024) CURRENT LIMITS OF MAJOR LANDSLIDE MOVEMENT (MARCH 2024) GPS Monument Displacement (October 10, 2022 to October 10, 2023) Displacement Vector Scale 1"=5' GPS Monument Displacement (October 10, 2023 to January 13, 2024) Displacement Vector Scale 1"=5' GPS Monument Displacement (January 13, 2024 to March 8, 2024) Displacement Vector Scale 1"=5' GPS Monument Displacement (March 8, 2024 to April 17, 2024) Displacement Vector Scale 1"=5' 365 days 95 days 55 days 40 days GPS Monument Displacement (April 17, 2024 to May 28, 2024) Displacement Vector Scale 1"=5'41 days AB01 AB02 AB04 AB05 AB13 AB16 AB17 AB20AB21 AB24 AB50 AB51 AB53 AB57 AB58 AB59 AB60 AB62 AB63 AB64 AB65 AB66 AB67 AB68 AB70 AB71 AB73 CR07 CR50 CR51 CR53 CR54 CW05 CW06 FT06 FT08 FT09 KC02 KC05 KC06 KC07 KC13 KC14 KC15 KC16 KC17 KC18 KC19 KC20 KC21 KC22 KC23 KC24 PB04 PB06 PB07 PB08 PB09 PB12 PB13 PB18 PB20 PB21 PB26 PB27 PB29 PB54 PB55 PB59 PB67PB68 PB69 PB70 PB71 PB72 PB73 PB74 PB75 UB02 RP01 AB74 AB75 AB76 KC25 KC26 KC27KC28 KC29 KC30 KC31 RP02 COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS RANCHO PALOS VERDES, CALIFORNIA SC6163 POS MP June 17, 2024 1"=500' PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY GPS MONITORING DISPLACEMENT MAP FIGURE NO. 1 Abalone Cove, Portuguese Bend, Klondike Canyon Hillshade basemap produced from publicly available LiDAR: "2015 - 2016 LARIAC Lidar DEM: Los Angeles Region, CA"NOTES: 1) October 10, 2023 GPS monitoring data was unavailable for monuments AB21, CR54, CW05, CW06, KC19, KC20, KC21, KC22, KC23, KC24, PB72, PB73, PB74, PB75, and RP01. 2) January 13, 2024 GPS monitoring data was unavailable for monuments AB20 and FT08. 3) March 8, 2024 GPS monitoring data was unavailable for monuments AB01, AB04, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. 4) April 17, 2024 GPS monitoring data was unavailable for monuments AB01, AB02, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. B-4Ordinance No. 686U Exhibit E Page 5 of 7 0 250 500 1000 (feet) PONY TRAIL PORTUGUESE BEND LANDSLIDE KLONDIKE CANYON LANDSLIDE ABALONE COVE LANDSLIDE ABALONE COVE PORTUGUESE POINT INSPIRATION POINT SACRED COVE APPROXIMATE BOUNDARY OF ANCIENT PORTUGUESE BEND LANDSLIDE COMPLEX BURMA ROAD NARCISSA DRIVE SWEETBAY ROAD PALOS VERDES DRIVE SOUTH CREST ROAD SEAVIEW TRACT CURRENT LIMITS OF MAJOR LANDSLIDE MOVEMENT (MARCH 2024) FLYING TRIANGLE LANDSLIDE EXPLANATION Limits of the Ancient Portuguese Bend Landslide Complex Limits of Historically Mapped Landslides 2023/2024 Landslide Mapping Current Limits of Major Landslide Movement (March 2024) GPS Monument Displacement Rate (October 10, 2022 to October 10, 2023) Displacement Vector Scale 1"= 8"/week GPS Monument Displacement Rate (October 10, 2023 to January 13, 2024) Displacement Vector Scale 1"= 8"/week GPS Monument Displacement Rate (January 13, 2024 to March 8, 2024) Displacement Vector Scale 1"= 8"/week GPS Monument Displacement Rate (March 8, 2024 to April 17, 2024) Displacement Vector Scale 1"= 8"/week 365 days 95 days 55 days 40 days GPS Monument Displacement Rate (April 17, 2024 to May 28, 2024) Displacement Vector Scale 1"= 8"/week41 days AB01 AB02 AB04 AB05 AB13 AB16 AB17 AB20AB21 AB24 AB50 AB51 AB53 AB57 AB58 AB59 AB60 AB62 AB63 AB64 AB65 AB66 AB67 AB68 AB70 AB71 AB73 CR07 CR50 CR51 CR53 CR54 CW05 CW06 FT06 FT08 FT09 KC02 KC05 KC06 KC07 KC13 KC14 KC15 KC16 KC17 KC18 KC19 KC20 KC21 KC22 KC23 KC24 PB04 PB06 PB07 PB08 PB09 PB12 PB13 PB18 PB20 PB21 PB26 PB27 PB29 PB54 PB55 PB59 PB67PB68 PB69 PB70 PB71 PB72 PB73 PB74 PB75 UB02 RP01 AB74 AB75 AB76 KC25 KC26 KC27KC28 KC29 KC30 KC31 RP02 COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS RANCHO PALOS VERDES, CALIFORNIA SC6163 POS MP June 17, 2024 1"=500' PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY GPS MONITORING DISPLACEMENT RATE MAP FIGURE NO. 2 Abalone Cove, Portuguese Bend, Klondike Canyon Hillshade basemap produced from publicly available LiDAR: "2015 - 2016 LARIAC Lidar DEM: Los Angeles Region, CA"NOTES: 1) October 10, 2023 GPS monitoring data was unavailable for monuments AB21, CR54, CW05, CW06, KC19, KC20, KC21, KC22, KC23, KC24, PB72, PB73, PB74, PB75, and RP01. 2) January 13, 2024 GPS monitoring data was unavailable for monuments AB20 and FT08. 3) March 8, 2024 GPS monitoring data was unavailable for monuments AB01, AB04, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. 4) April 17, 2024 GPS monitoring data was unavailable for monuments AB01, AB02, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. B-5 . 'l)) • -- ---p Ordinance No. 686U Exhibit E Page 6 of 7 0 250 500 1000 (feet) PONY TRAIL PORTUGUESE BEND LANDSLIDE FLYING TRIANGLE LANDSLIDE KLONDIKE CANYON LANDSLIDE ABALONE COVE LANDSLIDE ABALONE COVE PORTUGUESE POINT INSPIRATION POINT SACRED COVE APPROXIMATE BOUNDARY OF ANCIENT PORTUGUESE BEND LANDSLIDE COMPLEX BURMA ROAD NARCISSA DRIVE SWEETBAY ROAD PALOS VERDES DRIVE SOUTH CREST ROAD EXPLANATION Limits of the Ancient Portuguese Bend Landslide Complex Limits of Historically Mapped Landslides 2023/2024 Landslide Mapping SEAVIEW TRACT Current Limits of Major Landslide Movement (March 2024) CURRENT LIMITS OF MAJOR LANDSLIDE MOVEMENT (MARCH 2024) GPS Monument Displacement Rate (April 17, 2024 to May 28, 2024) Displacement Vector Scale 1"= 8"/week AB01 0.05 AB02 0.04 AB04 9.13 AB13 10.91 AB16 7.77 AB17 0.03 AB21 11.79 AB50 6.76 AB51 8.92 AB57 9.13 AB58 11.25 AB59 13.11 AB60 10.26 AB62 7.09 AB64 0.51 AB65 9.15 AB67 7.43 AB68 10.33 AB70 11.77 AB71 4.50 AB73 10.07 AB74 4.75 AB75 11.29 AB76 0.27 CR07 5.50 CR50 0.24 CR53 0.22 CR54 11.44 KC06 3.36 KC07 0.05 KC15 3.18 KC17 2.69 KC20 2.68 KC22 3.87 KC23 2.08 KC24 4.19 KC25 0.24 KC26 3.20 KC27 3.13 KC28 4.58 KC29 5.63 KC30 7.42 KC31 7.24 PB04 10.19 PB08 9.91 PB13 9.06 PB18 11.84 PB26 10.41 PB55 10.86 PB67 11.60 PB69 10.70 PB70 11.01 PB71 12.01 PB72 10.92 PB73 9.82 PB75 11.49 RP01 0.03 RP02 0.00 Elevations Table Minimum Rate (inch/week) 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 Maximum Rate (inch/week) 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 Color 10.00 11.00 11.00 12.00 12.00 13.00 13.00 14.00 COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS RANCHO PALOS VERDES, CALIFORNIA SC6163 POS MP June 17, 2024 1"=500' PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY GPS MONITORING DISPLACEMENT RATE CONTOUR MAP (5/28/24 DATA) FIGURE NO. 3 Abalone Cove, Portuguese Bend, Klondike Canyon Hillshade basemap produced from publicly available LiDAR: "2015 - 2016 LARIAC Lidar DEM: Los Angeles Region, CA"NOTES: 1) October 10, 2023 GPS monitoring data was unavailable for monuments AB21, CR54, CW05, CW06, KC19, KC20, KC21, KC22, KC23, KC24, PB72, PB73, PB74, PB75, and RP01. 2) January 13, 2024 GPS monitoring data was unavailable for monuments AB20 and FT08. 3) March 8, 2024 GPS monitoring data was unavailable for monuments AB01, AB04, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. 4) April 17, 2024 GPS monitoring data was unavailable for monuments AB01, AB02, AB05, AB20, AB24, AB53, AB63, AB66, CR51, CW05, CW06, FT06, FT08, FT09, KC05, KC13, KC14, KC16, KC18, KC19, KC21, PB06, PB07, PB09, PB12, PB20, PB21, PB27, PB29, PB54, PB59, PB68, PB74, and UB02. B-6 I I y .. -.r • .J l __,,,. • ■ ■ ■ ■ ■ ■ ■ n ■ ■ ■ r?."" I I I ( 0 ,-.: --:....., ,,, ---♦ r •• -♦ -r .... ~ • .,.,~ S) 95) " '\0-0 • I I J I / ~- / , z 0 ~ I/ ::J" J - I / - --- I (_ --I ___,.i r ----/ / ...,..... .... -i ----♦ , Ordinance No. 686U Exhibit E Page 7 of 7 Photos 1 and 2: Burma Road Trail, east of Vanderlip Trail. Left 6/22/24 and right 2/14/24 ORDINANCE NO. 686U EXHIBIT F Trails photos Ordinance No. 686U Page 1 of 5 Photos 3 and 4: Burma Road Trail, east of Vanderlip. Left 6/22/24 and right 2/14/24 Photos 5 and 6: Burma Road Trail, west of Water Tank Trail. Left 6/3/24 and right 3/21/24 Ordinance No. 686U Page 2 of 5 Photos 7 and 8: Burma Road Trail at the junction with Toyon Trail. Left 6/3/24 and right 2/14/24 Photos 9 and 10: Burma Road Trail, west of Panorama Trail. Left 5/30/24 and right 2/14/24 Ordinance No. 686U Page 3 of 5 Photo 11 and 12: Burma Road Trail, west of Barn Owl Trail. Left 6/2/24 and right 1/12/24 Photo 13: Olmsted Trail, south of Smuggler’s Trail . 6/1/24 Ordinance No. 686U Page 4 of 5 Photo 14: Olmsted Trail, west of Portuguese Bend Loop Trail . 6/1/24 Photos 15: Olmsted Trail, west of Portuguese Point Loop Trail. Left 6/1/24 and right 1/10/24 Ordinance No. 686U Page 5 of 5 ORDINANCE NO. 686U EXHIBIT G Neighborhood Photos Ordinance No. 686U Exhibit G Page 1 of 5 Ordinance No. 686U Exhibit G Page 2 of 5 Ordinance No. 686U Exhibit G Page 3 of 5 Ordinance No. 686U Exhibit G Page 4 of 5 Ordinance No. 686U Exhibit G Page 5 of 5 ::4``.:.4`ii4�• Mit CITY OF RA\CHO PALOS VERDES STATE OF CALIFORNIA ) COUNTY OF LOS ANGELES ) SS AFFIDAVIT OF POSTING CITY OF RANCHO PALOS VERDES ) The undersigned, being first duly sworn, deposes and says: That at all times herein mentioned, she was and now is the City Clerk of the City of Rancho Palos Verdes; That on September 4, 2024, she caused to be posted the following document entitled: ORDINANCE NO. 686U, AN INTERIM URGENCY ORDINANCE OF THE CITY OF RANCHO PALOS VERDES, CALIFORNIA, EXTENDING THE MORATORIUM ON THE ACCEPTANCE OR PROCESSING OF APPLICATIONS FOR AND ISSUANCE OF PERMITS, AND CONSTRUCTION OF ALL STRUCTURES WITHIN THE PORTUGUESE BEND LANDSLIDE COMPLEX ADOPTED BY ORDINANCE 674U AND EXTENDED BY ORDINANCE 675U, FOR AN ADDITIONAL 12 MONTHS, EXPIRING OCTOBER 2, 2025, a copy of which is attached hereto, in the following locations: City Hall Ladera Linda Community Park 30940 Hawthorne Blvd. 32201 Forrestal Drive Rancho Palos Verdes Rancho Palos Verdes Hesse Park 29301 Hawthorne Blvd. Rancho Palos Verdes I certify under penalty of perjury that the foregoing is a true and correct affidavit of posting. City-Clerk