Rancho Palos Verdes City Council Agenda July 16,2002





MAY 20, 2002


The meeting was called to order at 7:05 P.M. by Mayor McTaggart at Fred Hesse Community Park, 29301 Hawthorne Boulevard.

Following the Pledge of Allegiance, led by Councilman Clark, roll call was answered as follows:

PRESENT:Clark, Ferraro (arrived during closed session) Gardiner, Stern, and Mayor McTaggart


Also present were City Manager Les Evans, City Attorney Carol Lynch, Director of Public Works Dean Allison, City Clerk/Administrative Services Director Jo Purcell, and Recording Secretary Denise Bothe.


Mayor pro tem Stern moved, seconded by Councilman Gardiner, to approve the Agenda as submitted. Motion carried (Councilwoman Ferraro had not yet arrived).


The meeting was recessed at 7:07 P.M. to a closed session per the Brown Act Checklist.


At 7:25 P.M. the meeting reconvened.


City Attorney Lynch reported that no action had been taken.


Review of Geologic and Geotechnical Data for Zone 2

City Manager Evans presented staff report (of record) of May 20, 2002, and staff’s recommendation to:

A) Accept the conclusions of the Cotton, Shires & Associates January 14, 2002, Technical Review that:

1.There is insufficient subsurface information to properly characterize either the depth to the base of landsliding, strength properties of the landslide materials, or the ground water levels. Without these data, no accurate slope stability analysis can be undertaken, no reliable factor of safety can be calculated and no dependable landslide mitigation scheme can be designed.

2.One cannot quantitatively determine the factor of safety and, therefore, cannot judge the level of risk of development in the prehistoric landslide area.

3.The factor of safety of the landslide mass that underlies Zone 2 is above 1.00, but likely less than the industry’s standard safety threshold of 1.50.

B)Continue to deny requests for development permits for new homes in the Zone 2 area of the Portuguese Bend landslide based on the current lack of evidence that the subject land has a factor of safety of 1.5 or greater, unless an applicant submits a complete Landslide Moratorium Exclusion application that is supported by adequate geologic data.

City Manager Evans provided a brief history of the landslide areas in the Abalone Cove/Portuguese Bend landslide area; stated that the landslide was first discovered in 1974; that by 1978, it became clear that it was a serious problem, which prompted the City Council to adopt a building moratorium on September 5, 1978, for the Abalone Cove area. He commented on the installation of wells to remove ground water and other internal improvements to divert water out of the landslide area; and noted that there is no evidence of any significant movement in the area of the Abalone landslide after approximately 1985 and no record of any appreciable movement in the Zone 2 area of the Abalone Cove landslide. Highlighting Dr. Ehlig's May 1993 memorandum to the City, he explained that Dr. Ehlig had divided the Abalone Cove landslide into 8 zones, describing the geological characteristics of each zone and a scenario under which the properties in these zones could be developed. He explained that it wasn’t until February 21, 1995, that the City Council actually approved the appropriation for the environmental documents to consider a Zone 2 landslide exception project.

City Manager Evans stated that in early 2000, Jack Monks wrote a letter to the City to again address the Zone 2 issues; advised that the City Council had agreed to do so and, therefore, hired Cotton, Shires & Associates to study the existing data relating to in and around Zone 2 and to advise the City on various issues, including whether or not it would be advisable to allow building on the vacant lots in Zone 2.

Bill Cotton presented the results of his company's study; advised that he was hired to collect all the geologic/geotechnical data that pertains to the Zone 2 Abalone Cove and the Zone 1 area immediately surrounding the Abalone Cove landslide and to evaluate that data and see if that data was of sufficient technical merit to come to some reasonable conclusion about the stability of the landslide and the area that underlies Zone 2. Mr. Cotton stated that the data was collected from a variety of sources; stated that he researched 20 to 30 different references -- expressing his belief that he had collected all data that is available in order to judge how sound the data is. With the aid of slides, he highlighted the areas that had been addressed. Mr. Cotton stated that he concluded the existing data is insufficient to make a declarative statement about the long-term stability of the landslide as far as the standard of care in the industry to compute a factor of safety that would be recognized as being safe for development; explained that the level of risk is unknown, that the subsurface conditions are unknown and, therefore, he could not arrive at a level of risk.

Mr. Cotton stated that he also concluded that the building of several homes is not likely to cause enough aggravation to affect the landslide area; and explained that with a certain amount of restriction, just by constructing homes on the landslide is probably not likely to cause enough aggravation on the landslide to cause the landslide to move.

With the aid of a slide presentation, Mr. Cotton highlighted the various areas of the Abalone Cove area and Portuguese Bend area; stated that as you get down into the Abalone Cove landslide, you begin to see a repeated pattern to indicate a small displacement, about 4/10ths of an inch in movement -- a slow pattern which suggests that all the bore hole stations are moving towards the ocean, an active landslide that continues to creep. He stated that in Zone 2, there are some similar situations where things are moving down at the head of the landslide, that displacement is heading towards the ocean.

Highlighting the water well data, Mr. Cotton stated that he found that a lot of the water had been pumped out of the ground, which is a critical criterion for the long-term stability of the landslide.

Mr. Cotton stated for Mayor pro tem Stern that the accepted geotechnical standard is to look for a 1.5 factor of safety; explained that the lots could be developed without further destabilizing the large regional landslide, but confirmed that that’s not a standard that has been adopted by any standard-setting agency.

Mr. Cotton explained for Councilman Gardiner that the underlying landslide encompasses everything inside the larger boundary line as shown on the map of the Portuguese Bend Landslide Building Moratorium Area; stated that he does not know enough about this underlying landslide to make any comments about the subsurface being segmented or similar to various parcels within this zone. He confirmed that Zone 2 has one bore hole; that Zone 5 has two bore holes; and that Zone 1 has one bore hole and that they are deep enough to provide valuable information. Mr. Cotton reiterated his belief that building a house in this area, under certain controlled conditions, would not cause an aggravation to the larger Zone 2 region, would not cause it to be destabilized; and that it’s reasonable to suggest that the stability in the landslide 2 region isn’t so critical at that point where a house would destabilize it by itself, but pointed out once again that the risk is unknown.

Responding to Councilman Clark’s inquiry, Mr. Cotton stated that at this point, there isn’t enough subsurface data to determine a building safety factor; and that it’s clear there is no way to ascertain a building safety factor of 1.5, which is the standard for building in the gross landslide area.

Because a 1.5 factor cannot be reached at this point, Councilman Clark noted his concern with the Cotton report reflecting that it potentially would be okay to build in Zone 2, even under tight conditions.

Responding to Councilman Clark's comment, Mr. Cotton explained that it is a policy issue; that the level of risk is unknown, whether the risk is high or low; and that in his qualitative judgment, one house will most likely not destabilize the landslide. Mr. Cotton explained that he knows the factor of safety is above 1.00, that it is somewhere in between 1.00 and 1.5; and that from what he has seen in the Abalone Cove landslide itself, he would surmise that it probably hovers around 1.00. He explained that the land above this area will be a higher figure or else you wouldn’t see evidence of it moving.

Mr. Cotton explained for Mayor McTaggart that it would be expensive to investigate and determine what the factor of safety is in Zone 2; that it would require a great deal of sub-surface analysis to try to ferret out different parts of the landslide; that a drilling program would have to be developed; and that ground water and soil information would need to be obtained.

Mr. Cotton explained for Mayor McTaggart that exploratory holes could be used for extraction if they were designed for that purpose; that in determining the depth of the slide plane and the strength of materials, you’d probably run into water; and that the ultimate benefit would be to be able to extract water from that exploratory well or use it for monitoring the water level.

By way of a Power Point presentation, Mayor pro tem Stern addressed what he believes are appropriate determinations for this City Council to make based upon what has been heard and presented in regard to this matter. He highlighted the following facts: that the accepted geotechnical standard is 1.5; that there’s no recognized standard "to not further destabilize;" that the conclusions that the lots could be developed is not based on any recognized geotechnical standard; that the level of risk is unknown; and that there’s inadequate backup data from Dr. Ehlig’s 1993 recommendations. He pointed out that what is known is that some of the work that has gone on was designed to mitigate the impacts, particularly dewatering, sewers, yet the Cotton report points out there’s been no quantification of those mitigation measures. Lastly, he stated that the predictability of a future landslide is unclear.

Mayor pro tem Stern asked the City Council to make a determination that it find that the accepted geotechnical standard is a 1.5, noting that this is common in the geotechnical profession; that no recognized geological agency or standard-setting body has adopted a standard whether the development of the property "would further destabilize;" that the conclusion is not based upon the stability of the underlying geology, a conclusion that it "wouldn’t further destabilize;" that the level of risk is presently unknown; that the decision is a policy decision based upon the City’s willingness to accept the unknown level of risk; that Dr. Ehlig’s report lacks certain data or no quantification of the mitigation measures; and that there exists a fallacy in the conclusion that because of the age of this prehistoric landslide, that it is somehow stable. He noted his conclusion that the City should require that the development comply with the established standard of 1.5; that the City should not apply a standard which merely seeks to determine if the proposed development "will further destabilize;" and that the City should continue to follow a policy that would protect individuals who would inhabit structures built in Zone 2, not just be concerned about the impact of the development upon others.

Joan Kelly, 6 Fruit Tree Road, Zone 2, urged the City to continue its building moratorium in the Zone 2 area; and questioned if earthquakes are taken into consideration when making a determination.

Mr. Cotton noted for Ms. Kelly that yes, seismic issues are taken into consideration when determining slope stability.

Tim Kelly, 6 Fruit Tree Road, noted his objection to building any structure on any land less than a 1.5 stability factor.

Joe Gallagher, 9 Ginger Root Lane, RPV, asked that his e-mail letter of May 17th the City Council be entered into the record, noting that he recommends against the development of new homes in Zone 2. (This e-mail is on file with the City Clerk’s Office.)

Bob Halderman, 88 Narcissa Drive, RPV, urged the City to maintain the existing building moratorium until such time that a determination can be made that the factor of 1.5 has been reached.

John Monks, 107 Aspen Way, RHE, stated that the geologist and soils engineer he hired to investigate his 3 lots in Zone 2 came to the absolute conclusion that his properties exceed the 1.5 stability factor; that a determination had been made that building a house on his properties will have no destabilizing effect on his land or any land adjacent to it; and commented on his understanding that the Cotton report indicates that building on his property would not destabilize the hillside or do any harm to anyone.

Lois Larue, 3136 Barkentine Road, upper Abalone Cove, noted her concurrence with Mr. Cotton’s conclusion.

Denise who resides at 42 Oceanair Drive, supported the City maintaining a 1.5 standard for building in a known landslide area.

Monte Ray, geologist, cautioned the City that engineers make subjective judgments to be used in their calculations for the 1.5 factor of safety; explained that there may be a valid reason to look at ways that the City can go on developing in this area as it has a need to, taking other considerations into account. He noted the expense the City will incur if it decides to do this additional investigation; and expressed his belief that the final study will never yield a 1.5 factor of safety in this zone. He stated that there might be ways to do some building in this zone, that there are ways to do it in a relatively safe manner. He concurred with Mr. Cotton's statement that the level of risk is unknown in this zone.

In response to Councilwoman Ferraro’s inquiry, Mr. Ray explained that pumping ground water out of this zone has slowed the movement over the years; stated that there are structural design measures that one can use to combat the effects of land sliding if it were to occur.

Councilwoman Ferraro questioned what should be concluded from the extensive studies done on Mr. Monk's 3 lots that indicate stability of 1.5.

Responding to Councilwoman Ferraro's inquiry, Mr. Cotton explained that there are two different tests: one is for local stability, stating that that was part of the language -- that if there were going to be development on individual lots, they had to demonstrate that there would be local stability of 1.5. He noted that one could do that if one were on a slope, to come up with values for local geologic conditions. He pointed out that that situation only applies to building sites; and stated that that is totally different than what he is addressing in his report, which is the underlying stability of the larger mass. He added that one could probably demonstrate that there is local stability on one of those sites, but that the whole mass is moving; and that it doesn’t address the deep, underlying landslide mass and how it may come about in the future.

Mayor pro tem Stern stated that it is important for the City Council to start setting standards; explained that he sees no reason to deviate from the accepted standard of 1.5 -- pointing out that there are valid concerns for the stability of whatever structure is placed there for the current resident and any future resident; and advised that he would not support a change at the present time given the unknown level of risk.

Mayor pro tem Stern moved, seconded by Councilman Gardiner, to concur with staff's recommendation and moved to include the 7 additional findings he presented during his Power Point Presentation.

Councilman Clark echoed Mayor pro tem Stern' position; and stated that in light of the information presented, it would be prudent for this City to reject any building construction in the moratorium area.

City Attorney Lynch suggested that with respect to Mayor pro tem Stern’s suggestion Nos. 3 and 4, that we add the proviso in the conclusion noted in Cotton January 2002 report, add the words "undeveloped lots"; and the same type of change in No. 4, geologically, the level of risk of development of undeveloped lots in Zone 2 presently is unknown, the decision to allow new residential development in that area given the unknown level of risk is a policy decision which must be made by the City Council.

Councilman Gardiner expressed his belief that the potential for risk could negatively impact the taxpayers of the City.

Councilman Clark pointed out that it is very clear in the Cotton report that Dr. Ehlig did not base his recommendations on specific geotechnical analysis and that it is his belief that therein lies the weakness in those recommendations; and stated that some of the more recent data calls into question some of those assumptions that were made several years ago.

Hearing no objection to the motion, it was so ordered by Mayor McTaggart.


Cathy Snell, 8 Vanderlip Drive, stated that due to the City Council's vote to continue on with the building moratorium in Zone 2, she urged the City to abandon its RDA plans to build over 200 new homes in the blighted/landslide area.

Mayor McTaggart stated that the Mayor of Rolling Hills Estates was asked to approach him concerning a border and landslide issue which is negatively impacting Rolling Hills businesses; and that the Mayor of Rolling Hills Estates suggested that both cities hire a consultant to address this border/landslide issue.


At 9:20 P.M. the meeting was adjourned to Tuesday, May 21, 2002, 6:00P.M., at Hesse Park to interview candidates for the Equestrian Committee Chair.





City Clerk