Rancho Palos Verdes City Council

October 7, 2006 RANCHO RANCHO PALOS VERDES CITY COUNCIL AGENDA - Landslide Workshop- The Abalone Cove Landslide Abatement District (ACLAD) October 7, 2006 RANCHO RANCHO PALOS VERDES CITY COUNCIL AGENDA - Landslide Workshop-The Abalone Cove Landslide Abatement District (ACLAD) October 7, 2006 RANCHO RANCHO PALOS VERDES CITY COUNCIL AGENDA - Landslide Workshop-The Abalone Cove Landslide Abatement District (ACLAD)


The Abalone Cove Landslide Abatement District (ACLAD) is a “geologic hazard abatement district" created by the City of Rancho Palos Verdes under special legislation passed by the California Legislature in l980 for the “purposes of prevention, mitigation, abatement or control” of the Abalone Cove landslide. It was the first geohazard abatement district created in the state. The District is governed by five elected Directors, which serve for a term of four years. Under the California Improvement Act of l911, the District may assess properties benefiting from the mitigation or abatement efforts for the cost of the improvements.

In September 1978, the City Council of Rancho Palos Verdes was informed about cracks and movement along Palos Verdes Drive South and Narcissa Drive that indicated a new landslide (actually a reactivation of an old landslide) that was named the Abalone Cove landslide. The Council immediately established a building moratorium in the area and authorized the first in a series of geological investigations to define the problem and identify potential solutions.

During March, l979, proposed legislation designed to permit the creation of a Geological Hazard Abatement District was forwarded to Senator Beverly and Assemblywoman Ryan for introduction as an emergency measure. At the same time, the Council hired Robert Stone and Associates to perform a comprehensive hydrogeologic investigation to determine the feasibility of dewatering the landslide. Later that year, the preliminary borehole tests favored installing a series of dewatering wells.

On January 1, l980, Senate Bill 1195 authorizing the formation of a Geologic Hazard Abatement District become law as Division 17 of the Public Resources Code. The City Council immediately adopted Resolution 80-3, creating the Abalone Cove Landslide Abatement District (ACLAD).

During the interim period, property owners within the greater Abalone Cove area voluntarily financed the drilling of six dewatering wells and began pumping operations by mid-April, l980. In November, l980, following the formation of ACLAD, the property owners transferred the wells to the District.

ACLAD is broadly responsible for abatement efforts to prevent movement of the Abalone Cove landslide. To do this, the district operates and maintains dewatering wells and associated discharge lines, easements to assure access to the dewatering facilities, monitors the groundwater elevations in the greater Abalone Cove area, reviews biannual measurements of the Global Positioning System (GPS) stations for evidence of slide movement and works with the City of RPV to maintain certain storm drain culverts and other improvements related to landslide abatement. The majority of the board’s time, effort and annual expenditures are directed at maintaining the dewatering wells and discharge lines.

RDA Bond Funds
The 1987 Reimbursement and Settlement Agreement between the City of Rancho Palos Verdes, the Rancho Palos Verdes Redevelopment Agency and the County of Los Angeles directed the creation of a Joint Powers Maintenance Authority (JPMA) to oversee the on-going maintenance of capital improvements constructed by the Redevelopment Agency with the bond proceeds. The Agreement further stipulated that $1 million of the bond proceeds be set-aside in a separate maintenance trust fund. The accrued interest on this fund can be used only for maintenance purposes. The original principal amount of $1 million cannot be expended. The interest earnings are to be used to maintain the landslide abatement improvements constructed by the RDA pursuant to the Reimbursement and Settlement Agreement, with the exception of sewer systems. In addition, the funds generated by the maintenance trust fund may also be used, to the extent not otherwise used for the maintenance of improvements constructed pursuant to the Settlement Agreement, to maintain public landslide abatement improvements that were not constructed with the proceeds of the assessment bonds.

A separate Joint Powers Improvement Authority was created in FY 96-97 to oversee the on-going maintenance and operating expenses associated with the improvements constructed by the Rancho Palos Verdes Redevelopment Agency. Separate funds have been established to record the maintenance activities associated with the Abalone Cove and Portuguese Bend areas of the Agency. The City and Redevelopment Agency govern the Authority jointly. Funding for the expenses associated with the Portuguese Bend Landslide area are provided through a transfer from the City's General Fund.

On May 2, 2000, the JPMA authorized the use of a portion of the investment earnings (up to $60,000 annually) in the maintenance trust fund to assist in paying for the maintenance and utilities associated with the thirteen dewatering wells, pumps, and pipelines which were in existence prior to the Reimbursement and Settlement Agreement. A copy of the JPMA/ACLAD Agreement is included as Attachment A in the appendix.

ACLAD assessments
ACLAD charges property owners an annual assessment for the operation and maintenance of the various abatement facilities and ACLAD administrative costs. In fiscal 2001 the District collected about $ 64,500 in assessments, which together with income from cash reserves supported a total expenditure of $ 76,000. Of this sum, about $ 46,600 was spent directly on maintenance.

In addition $ 60,000 were provided by the City from the Horan Maintenance fund through the JPMA/ACLAD Agreement that was used for a special maintenance project to rehab older wells with declining production.

Data Collection/Records Maintenance
Annually ACLAD collects data on ground water elevations, well maintenance and production, the condition and repair to discharge lines and performance of the GPS monitoring system. These data are important in assessing the effectiveness of the abatement efforts and over the long-term, contribute to better understanding the relationship between well production, groundwater elevations, rainfall and land movement.

Dewatering wells
ACLAD currently operates and maintains 17 dewatering wells in the Abalone Cove landslide area. These fall into three categories: wells drilled during the formation of ACLAD by the interim homeowners association, wells drilled under the authority of ACLAD, funded by issuance of a bond, and wells drilled by the City/RDA funded by the Horan Settlement funds and subsequently transferred to ACLAD under an agreement between the City and the District.

While diligent care has extended the service-life of these wells beyond that normally expected, all of the older wells drilled in l980-81 and some of those drilled in the mid l980s now have declining production and cannot be effectively pumped because corrosion and rust has plugged the casing perforations. These wells are in need of major maintenance, including redrilling and, within the landslide area, deepening. Eventually, all the dewatering wells will need to be improved and some may require redrilling. To maintain the dewatering wells at a high level of production, two to three wells should be rehab or redrilled each year on a rotational basis.

Dewatering pumps
Pumps are an important item in the dewatering wells and require constant maintenance. Early wells used 5 hp turbine pumps but as well performance was evaluated, pumps were changed to deepwater 0.5 to 2 hp submersible pumps. The service life of pumps varies with age, volume of water removed and degree of fouling. Wells located in the area south of PV Drive South require special attention as the groundwater carries a high concentration of iron-rich compounds that foul the pumps.

Discharge lines
Water from the dewatering wells is discharged through a system of 2 to 4 inch diameter PVC pipes that feed into a main collector that carries the water across the landslide area and empties into the ocean at the inter tidal zone between Portuguese Point and Abalone Cove beach. Liaison is maintained with Los Angeles County (?) Sanitation District who treat and clean the lines when notified of elevated bacterial levels in samples from the discharge. The original discharge lines were aluminum (above ground) and steel (buried street crossings) that corroded over time and have been converted to more durable PVC pipe. The buried street crossings are now failing and being retrofitted with flexible hose. A major maintenance project will be to replace the steel pipe which caries the discharge water from Palos Verdes Drive South down to the ocean.

Drainage facilities
ACLAD maintains two storm drain culverts: the 10 ft CMP culvert in Altamira Canyon that runs beneath lower Narcissa Drive and connects to the culvert beneath PV Drive South and a CMP drainage channel that runs from the end of Figtree to Altamira Canyon. These culverts are part of the storm drainage system and require regular maintenance and repair due to damage from storm runoff. In a joint project with the City, ACLAD has relined the bottom of the culvert beneath Narcissa Drive and at some point in time the culvert will have to be replaced.

GPS points
Abbott and Associates maintain the Global Positioning System monuments located within Abalone Cove landslide area under a contract with the City of Rancho Palos Verdes. Data are collected twice a year, in February-March, the rainy season, and in August-September, the dry season. Since the death of Dr. Perry Ehlig, ACLAD, through an arrangement with Dr. Susan Owens at the University of Southern California, has reviewed all of the GPS data collected since inception of the system (ca. 1994), reduced the data, created maps displaying the horizon and vertical movement and summarizing the results.