US Army Corps of Engineers, April 26, 1995, "Rancho Palos Verdes, California, Shore Protection and Environmental Restoration Feasibility Study" Public Information Workshop � .2, i
US Army Corps
of Engineers
Los Angeles District
RANCHO PALOS VERDES, CALIFORNIA
SHORE PROTECTION AND ENVIRONMENTAL
RESTORATION FEASIBILITY STUDY
PUBLIC
INFORMATION
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FRED HESSE COMMUNITY PARK BLDG. J .Nt'a
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29301 HAWTHORNE BLVD. '�• ‘• tit'id
RANCHO PALOS VERDES, CALIFORNIA �' '• 1
7:30 P.M. WEDNESDAY �^ '
APRIL 26,1995 , \ ,•
40i OF d� DEPARTMENT OF THE ARMY
��', \ LOS ANGELES DISTRICT.CORPS OF ENGINEERS
- P.O 005 2711
I'H LOS ANGELES,CALIFORNIA 90053.2325
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REPLY TO
ATTENTION OF
Office of the Chief April 7, 1995
Coastal Resources Branch
To Interested Persons:
• The U. S. Army Corps of Engineers, Los Angeles District, and
the City of Rancho Palos Verdes have initiated a feasibility
study to develop a solution to the problem of sh re on and
ecologicalamage along the coast of the City of Rancho Palos
Verdes. T'hie '.u" vat so determine the Federal i nterest in
that solution.
A public workshop will be held on Wednesday, April 26, 1995,
at 7:30 P.M. at the Fred Hesse Community Park Building, 29301
Hawthorne Boulevard, in the City of Rancho Palos Verdes, Califor-
nia. The purpose of the public information meeting is to inform
the public about the current feasibility study, and to solicit
public interest and participation in the Corps study process.
The meeting will also provide an opportunity for individuals and
organizations to express areas of concern that need to be
addressed in an Environmental Impact Statement in accordance with
NEPA and CEQA guidelines.
All interested persons and organizations are invited to be
present or represented. Please plan to attend so that your ideas
and interests about the Rancho Palos Verdes shore protection,
environmental restoration, and related issues can be identified
and subsequently addressed in the study. The meeting will be
informal , and everyone is encouraged to express their views about
the study area problems, needs, and the potential benefits to the
environment. Some background information on the study is
• presented in the following pages.
We have attempted to send this announcement information to
• all individuals and organizations that may have an interest in
the Rancho Palos Verdes shore erosion problems. If you know
anyone who would like to attend, please bring this invitation to
their attention.
1
If you cannot attend this meeting, we would still appreciate
your views and comments, including the type of information
requested in this announcement-brochure. Please send your reply
letter to the U. S. Army Corps of Engineers, Los Angeles
District, P. 0. Box 2711, Los Angeles 90053-2325, to the atten-
tion of Ms. Anna Zacher, Study Manager. Ms. Zacher can also be
contacted at 213/894-2028 if you have any questions concerning
the study or the workshop.
•
BACKGROUND OF THE STUDY
The U.S. Army Corps of Engineers, Los Angeles District, was
initially authorized to study the feasibility of shoreline
erosion mitigation measures along the Rancho Palos Verdes coast-
line and in the City of Rolling Hills that could provide
additional stability for the Portuguese Bend landslide and
adjacent landslides. The study had been authorized under
Section 712 of the Water Resources Act of 1986, Public Law 99-
662. The reconnaissance phase of the study was completed in
. 90, *and a report identified everal potential projects;
'however, .n9` it `was determined by the Assistant Secretary of
Army that this was a landslide study, and not within the Corps'
'mandate. The Corps could not, therefore, participate in a
potential Federal project whose project purpose was landslide
stabilization.
In 1994 the Congress added funds for a feasibility study,
and diFFEEn the Corps to proceed with a cost-shared study that
would 4d4z2ss shore protection only for environmental restoration
at the Rancho Palos Terse e. e s ' .y . - g
performed in partnership with the City of Rancho Palos Verdes in
accordance with anagreement signed in Decem r 1994.
The purpose of the current study, therefore, is to develop a
shore protection project that would provide for restorati of
the natural ma • e habitat at Rancho Palos Verdes. e feasi i-
lity s u y will evaluate all viable solutions that may reduce
shoreline erosion, as well as evaluate the environmental benefits
associated with the reduction of sediment and turbidity and
restoration of rocky intertidal conditions . If a project is
found to be justified, the Federal interest will be determined,
and a recommendation will be made to Congress on whether the
project should be constructed as a Federal project.
2
DESCRIPTION OF THE STUDY AREA
The study area is located along the coastline of the Palos
Verdes Peninsula in the City of Rancho Palos Verdes, specifically
at the shorelines of Abalone Cove and Portuguese Bend, as
delineated in Figure 1. The topography of the area consists
• primarily of a shoreline backed by steep slopes below a
pronounced sea cliff, and is also characterized by rocky
headlands, and gravelly, narrow beaches.
Since 1956 when the current landslide movement began,
thousands of tons of material have been eroded by waves and tide
from the shoreline, and deposited in the nearshore and offshore
zone. As much as 30 inches of sediment have been deposited over
the rocky intertidal and subtidal bottom, and up to 6 inches of
sediment have been measured as far offshore as 300 feet. The
areas of identified landslide sediment dispersion are depicted in
Figure 2. Approximately 1,900 acres of coastal , nearshore and
offshore habitat have been affected.
DESCRIPTION OF SOME ALTERNATIVE MEASURES
The Los Angeles District will investigate and evaluate all
reasonable alternatives and methods to reduce shore erosion,
sedimentation, and turbidity along the Rancho Palos Verdes
coastline. The potential construction of structures such as
revetments or gabions along the shoreline, or dikes or
breakwaters in the nearshore area, a no action plan, as well as
others, will be considered. Some of these measures are listed
below and depicted in graphic form in Figure 3 to show examples
of some types of shore protection measures.
■ REVETMENT: facings of rock placed on bank or bluff to
protect a slope, embankment, or shoreline
structures to protect against erosion by
waves, tide, or currents;
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Figure 3. Examples of Beach Erosion Control Structures
ismotaliop.W' -.144
• I �••�QUIIRRYAlJH f..1411P"'ccoaq•: �i�
REVETMENT PROTECTIVE DIKE
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_toe OCEAN
P
OFFSHORE BREAKWATER
• 6
■DIKES AND SEA WALLS: structures of concrete or timber
bulkhead constructed at the
shoreline, primarily designed to
prevent erosion and other damage
due to wave and tidal action;
■ BREAKWATER: a fixed structure, which can be partially or
completely submerged, that can protect a
shore area by interception of incoming waves
and tide.
POTENTIAL BENEFITS
Prior to the occurrence of the landslide in 1956, the marine
rocky shore environment at Abalone Cove and Portuguese Bendwasa
premier kelp-rock reef habitat for marine organisms. It was
protected against most sea swells, and was renown for its clear,
quiet waters. Since the onset of the landslide, these waters •
have become turbid, and large portions of the rock bottom have
been overlain by landslide sediments. Marine plants,
invertebrates, fish, birds, and mammals that previously inhabited
this environment have been impacted by the ongoing sedimentation
and turbidity, and many can no longer be found. Portuguese Bend
has been particularly impacted. At Portuguese Bend, rocky shore
organisms have been displaced or buried by sediments and replaced
by soft bottom species.
A protective measure that would control the shore erosion
could provide the opportunity for dispersion of the sediment out
of the area. The re-exposure of the natural bottom would again
provide a suitable marine habitat for the previous rocky
intertidal and subtidal species and biological communities.
TYPES OF INFORMATION
The types of information for the Rancho Palos Verdes
shore protection and environmental restoration feasibility study
that the Corps of Engineers can use to effectively conduct the
study, is listed below. Public involvement and citizen
participation are both vital to the success of the study, and
your input will greatly assist the Corps planners .
1. Problems and needs.
Your view about the problems and needs of the Rancho
Palos Verdes coastline
2. Environmental concerns .
3. Types of measures to be addressed.
Ideas and preferences as to the type of options that might be
implemented to protect the shoreline
4. Potential project impacts .
Concerns about any potential alternative measure that may be
proposed, and the potential negative or positive impacts to
the coastline and marine environment.
5. Other.
You may use these issues as a guide for any presentation you
wish to make during the meeting, or mail your responses to:
U. S. Army Corps of Engineers
Los Angeles District, P.O. Box 2711
Los Angeles, California 90053
Attn: Anna Zacher, Study Manager, CESPL-PD-CS
Name:
Address:
Phone:
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