Abalone Cove

Position paper · v1 · April 2026

The 24-inch line at Abalone Cove

A working hypothesis on APNs 7573-006-024 and 7573-007-900, and the five steps that would confirm or refute it.

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Summary

A 24-inch diameter line appears within or immediately adjacent to two parcels on the inland edge of Abalone Cove, Rancho Palos Verdes — Assessor's Parcel Numbers 7573-006-024 (0 Clipper Road, a vacant 1.56-acre lot currently held by Clipper Development LLC) and 7573-007-900 (an unbuilt strip held by the former Rancho Palos Verdes Redevelopment Agency's successor under the Long Range Property Management Plan). The two parcels sit within the broader Portuguese Bend / Abalone Cove landslide complex, which has been moving continuously since 1956 and which the City of Rancho Palos Verdes' own 2018 Zone 2 Environmental Impact Report identifies as a system in which groundwater is the controlling factor and in which residential plumbing has been named as the likely catalyst for slide onset.

Several features of the corridor — its diameter, its alignment, and its apparent absence from the maintained inventories of the City and of Los Angeles County Sanitation Districts — are consistent with a remnant of the pre-1956 Palos Verdes Coast Road right-of-way, recorded at Book 6059 page 178 of the Official Records of Los Angeles County. That right-of-way predates the 1956 reparceling of the area, predates the onset of slide movement, and predates the 1957 Filiorum subdivision (Tract 23434) that truncated its western end. Whether the line is active, abandoned, maintained by anyone, or disconnected from any larger system is not, at this writing, documented in any record the Foundation has been able to locate.

This paper states a hypothesis, not a finding. It sets out what the Foundation believes may be happening, why the question matters, and what five public-records and field-investigation steps would confirm or refute it. It is written to prompt those five steps, not to assert a conclusion.

The site

APN 7573-006-024 is a vacant 1.56-acre lot at the west end of Clipper Road, at the inland edge of Abalone Cove on the south side of the Palos Verdes Peninsula. Its legal description is Lot 1 of Tract 43725, per map recorded in Book 1063 pages 91-92 of Maps. The 2026 chain-of-title report prepared by CTC of California (order R213541248, dated March 25, 2026) records ownership by Clipper Development LLC, a California limited liability company with a mailing address at 4199 Bandini Boulevard, Vernon, since October 2021. Current zoning is RPS1OOOSP (residential with Palos Verdes specific-plan overlay). The 2025 assessed value is $2,334,657 on annual property taxes of $34,618.97. An active $2.1 million commercial loan from Hankey Capital LLC was recorded against the parcel on November 4, 2025.

APN 7573-007-900 is an adjoining parcel retained by the Rancho Palos Verdes Redevelopment Agency's successor under the 2014 Long Range Property Management Plan (LRPMP), which reclassified certain former-agency parcels for eventual disposition or retention as governmental-purpose property. The parcel's boundaries, as depicted in the 1985 Assessor Map for 7573-7, follow the truncated edge of what the 1949 and 1957 tract maps identify as a public road corridor of approximately 50 feet in width.

Both parcels lie within the City of Rancho Palos Verdes and within Zone 2 of the City's Landslide Moratorium Area. The immediately adjacent Abalone Cove Landslide has been undergoing documented reactivation since 1974.

What we see

Three things stand out about the corridor:

  1. A line of approximately 24-inch diameter is visible — in above-ground vents, in a portion of the grading, and in one surviving 1985 County assessor annotation — running roughly along the north edge of APN 7573-006-024 and the south edge of APN 7573-007-900, on a bearing consistent with the Coast Road alignment shown on the 1882 Rancho de los Palos Verdes partition map and the 1914 Olmsted topographic survey.
  2. The line does not appear on the City of Rancho Palos Verdes' publicly-available GIS sewer layer or storm-drain layer. The Foundation has not yet located a Sanitation Districts of Los Angeles County (LASD) sewer-atlas page that depicts the corridor. The LRPMP materials for APN 7573-007-900 do not enumerate any maintained utility within the parcel.
  3. The corridor sits inside the Ancient Portuguese Bend Landslide boundary as defined by the California Geological Survey and as adopted by the City in its Zone 2 EIR. The 2011 LGC Valley, Inc. geotechnical study, incorporated into the EIR, records continuing movement of the Abalone Cove reactivation and names groundwater as the controlling factor.

Why the question matters

The position paper's subject is narrow — one line, in one corridor, on two parcels — but the context matters because of what the City of Rancho Palos Verdes has already said about how the Portuguese Bend / Abalone Cove system works. The 2018 Zone 2 EIR, drawing on the 2011 LGC Valley study and on Robert Stone & Associates (1979), states plainly:

"Early in the development of the Portuguese Bend area, septic systems, leach lines and cesspools installed as part of residential development on the APBL contributed high volumes of water directly into the landslide." (Zone 2 EIR §4.5-5)
"Groundwater was concluded to be the most likely agent responsible for the slide movement of the 80-acre ACL." (Zone 2 EIR §4.5-5)
"evaluation of the driving force produced by the groundwater head indicates it is the controlling factor causing the slide movement." (Stone & Associates 1979, cited at Zone 2 EIR §4.5-6)

An unmaintained, water-bearing underground line of unknown disposition, sitting inside this landslide complex, within a corridor whose recorded history predates modern utility mapping, is a fact the Foundation believes a reasonable reader should want confirmed or refuted. If the line is live and leaking, it is a continuing anthropogenic water contribution to a formation the City's own consultants have said is controlled by groundwater. If the line is abandoned and dry, the matter is closed and the Foundation will say so.

The worst outcome is not discovering the line is leaking. The worst outcome is never finding out.

Working Hypothesis

the 24-inch line on APNs 7573-006-024 and 7573-007-900 is a remnant of the pre-1956 Palos Verdes Coast Road right-of-way (Book 6059 p.178), may be disconnected from the modern sanitary sewer system, and may be exfiltrating water into the lower Filiorum canyon along Parcel 106 boundaries altered in the 1956 reparceling. In a landslide zone where groundwater is the controlling factor (2011 Zone 2 EIR) and residential plumbing is named as the likely 1956 catalyst, an unmaintained water-bearing line in this location is a mechanism-of-action explanation consistent with the onset and persistence of slide movement.

What would confirm or refute this

  1. Title search on the PV Coast Road 50-foot ROW (Book 6059 p.178) — date and manner of abandonment; infrastructure disposition.
  2. 1956 reparceling map overlay — did Parcel 106's boundary move across the line?
  3. LA County Sanitation District + RPV Public Works inventory — is the line maintained? Last inspection?
  4. Dye trace or CCTV inspection of the line.
  5. ACLAD dewatering well hydrology — signature consistent with an anthropogenic water source on the corridor?

The Foundation has prepared draft CPRA request templates for steps 1 and 3. Contributors with standing to file are invited to pick up and send them; the Foundation will post the responses when they return. See /position/contribute/ if you hold a record relevant to any of these five steps.

What we are asking the City to do

We are asking the City of Rancho Palos Verdes, the Sanitation Districts of Los Angeles County, and any other agency with custodial responsibility for underground infrastructure in this corridor to:

  1. Publicly identify the operator of the 24-inch line on or adjoining APNs 7573-006-024 and 7573-007-900, or publicly state that no agency records responsibility.
  2. Produce the inspection history, if any, of the line.
  3. Conduct, or commission, a CCTV or dye-trace inspection of the line.
  4. Report the results publicly, to the Coastal Commission and to the Department of Housing and Community Development, before any further entitlement decision on APN 7573-006-024.

We are not asking for a halt to development on the peninsula. We are asking that the City's own 2018 position — that groundwater is the controlling factor in the Portuguese Bend / Abalone Cove landslide complex — be applied consistently to a specific parcel on which the City has, in parallel, authorized high-density residential rezoning.

What this paper is not

This paper is not a lawsuit. It is not a nuisance complaint. It is not a position against the current owner of APN 7573-006-024 or against any developer with an entitlement interest in the parcel. It is not a position against the City of Rancho Palos Verdes or its staff. It is not a position against the Housing Element, against SB 9, or against SB 330. It does not contest the legal authority of any of those statutes.

This paper is a request for a specific factual record on a specific underground line, and a hypothesis about why that record is worth producing before further irreversible decisions are made.

If, in response to the five investigative steps, the record shows the line is maintained, inspected, and dry, the Foundation will retract this paper and say so on the same page. If the record shows the line is uninspected but intact, the Foundation will narrow the hypothesis to the disposition question. If the record shows exfiltration, the Foundation will forward that record, without editorial commentary, to the City, the Coastal Commission, and HCD.

Sources

Additional source cards at /evidence/.

Version

v1 · April 2026 · Contribute a correction or a record. This paper will be versioned; subsequent versions will be linked here with changelogs. The hypothesis stated above is intentionally falsifiable; if any one of the five investigative steps returns a clear answer, the paper will be updated to reflect the new record and the hypothesis narrowed, confirmed, or retracted in place.

Read the plain-language version of this hypothesis in the story →