REVISED GEOTECHNICAL ENGINEERING EVALUATION PHASE III ROCK SLIDE
POTENTIAL INSPECTIONS ROCKFALL HAZARD RATING SYSTEM DATABASE UPDATE
NO. 1 PROJECT NO. 01154 VARIOUS LOCATIONS, OAHU, HAWAII W.O.
4683-20 NOVEMBER 16, 2012
Prepared for
CITY AND COUNTY OF HONOLULU DEPARTMENT OF DESIGN AND
CONSTRUCTION
REVISED GEOTECHNICAL ENGINEERING EVALUATION PHASE III - ROCK
SLIDE POTENTIAL INSPECTIONS ROCKFALL HAZARD RATING SYSTEM DATABASE
UPDATE NO. 1 PROJECT NO. 01154 VARIOUS LOCATIONS, OAHU, HAWAII W.O.
4683-20 NOVEMBER 16, 2012
TABLE OF CONTENTS Page SUMMARY OF FINDINGS AND
RECOMMENDATIONS................................................ i
1. GENERAL
........................................................................................................
1 1.1 Introduction
................................................................................................
1 1.2 Project
Considerations...............................................................................
1 1.3 Purpose and Scope
...................................................................................
4 BACKGROUND
...................................................................................................
6 2.1 Study
Objective..........................................................................................
6 2.2 Hillslope Inventory and Preliminary Rating Method of Study
..................... 6 2.2.1 Hillslopes Applicable to the RHRS
.................................................. 7 2.2.2
Hillslope Conditions Excluded from the
RHRS................................ 8 2.2.3 Methods of Preliminary
Hillslope Evaluation and Rating ................. 8 2.2.4
Preliminary Hillslope Rating
............................................................ 9
2.2.5 Hillslope Site Identification
............................................................ 10
GEOLOGY
......................................................................................................
11 3.1 Regional Geology
....................................................................................
11 3.2 Geology and
Rockfall...............................................................................
12 3.2.1 Saprolite/Mixed Rock Hillslopes
.................................................... 13 3.3
Geography and Rockfall Distribution
....................................................... 14
DISCUSSION AND RECOMMENDATIONS
...................................................... 16 4.1
Findings
...................................................................................................
16 4.1.1 Slope Evaluation and Rating
......................................................... 17 4.1.2
Rockfall Incident Reports by Maintenance
Division....................... 18 4.1.3 Hillslope Ownership
Assessment .................................................. 19
4.2 Recommendations
...................................................................................
20
LIMITATIONS.....................................................................................................
22
2.
3.
4.
5.
CLOSURE.....................................................................................................................
24
W.O. 4683-20
GEOLABS, INC.Hawaii y California
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TABLE OF CONTENTS
PLATES Island of Oahu Key Map
..............................................................................
Plate 1 Area Maps
...............................................................................
Plates 2.1 thru 2.22 Slope Inventory and Preliminary Classification
......................... Plates 3.1 thru 3.7 Summary of Slope
Ownership Assessment .............................. Plates 4.1 thru
4.9 Summary of Preliminary Slope Property Ownership................
Plates 5.1 thru 5.13 APPENDIX Summary A Slope Detail Rating
................................................... Pages 1 and
2
W.O. 4683-20
GEOLABS, INC.Hawaii y California
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REVISED GEOTECHNICAL ENGINEERING EVALUATION PHASE III - ROCK
SLIDE POTENTIAL INSPECTIONS ROCKFALL HAZARD RATING SYSTEM DATABASE
UPDATE NO. 1 PROJECT NO. 01154 VARIOUS LOCATIONS, OAHU, HAWAII W.O.
4683-20 NOVEMBER 16, 2012
SUMMARY OF FINDINGS AND RECOMMENDATIONS
A Rockfall Hazard Rating System (RHRS) program was initially
established in 2002 at various locations adjacent to City streets
on the Island of Oahu, Hawaii. A total of 256 hillslope sites
(rockfall sections) within 122 City streets were identified and
rated as Class A (High), Class B (Moderate), or Class C (Low) with
respect to the level of hazard associated with the potential for
rockfall to encroach on the public right-of-way. There were 56
rockfall sections that were assessed an A classification, 93
rockfall sections with a B classification, and 107 rockfall
sections with a C classification. According to the RHRS program
guidelines, the hillslope inventory and database information should
be updated periodically to reflect possible changes in slope
conditions, recent construction and/or maintenance activities,
recent rockfall and rock slide events, escalated construction cost,
and other pertinent factors. This report covers updates to the
slope inventory (Stage 1) and preliminary rating (Stage 2). Stage 1
involved the revision of the existing inventory of rock hillslopes
that have the potential to produce falling rock and could affect
the public road right-of-way. Stage 2 involved subjective
geological evaluation and preliminary rating of the inventoried
hillslopes for the purpose of classifying the slopes with respect
to the level of potential rockfall hazard. The preliminary slope
ratings for many of the hillslope sites are either upgraded from
lower rank to higher rank, or downgraded from higher rank to lower
rank. There are 59 rockfall sections that have been assessed an A
classification, 93 rockfall sections with a B classification, and
104 rockfall sections with a C classification. The updated
preliminary ratings will result in changes to the rockfall
remediation prioritization. We believe that the efforts of these
updates will assist in effectively and efficiently managing the
rockfall remediation planning with respect to the relative level of
potential hazard on public right-of-way. Additional information
such as slope ownership assessment for each hillslope is also
included in the update program. We believe that the ownership
assessment may be useful for prioritization of rockfall remediation
with respect to legal and constructability issues. W.O. 4683-20
GEOLABS, INC.Hawaii y California
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SUMMARY OF FINDINGS AND RECOMMENDATIONS
The text and appendix of this report should be referred to for
detailed discussion and the slope inventory and preliminary slope
classification.END OF SUMMARY OF FINDINGS AND RECOMMENDATIONS
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SECTION 1. GENERAL 1.1 Introduction This revised report presents
the results of our geotechnical engineering evaluation performed
for the Rockfall Hazard Rating System (RHRS) rock slide potential
inspections update No. 1 project for the City streets located on
the Island of Oahu, Hawaii. The general location and vicinity of
the various hillslope sites that were
inspected for this project are shown on the Island of Oahu Key
Map, Plate 1. This report summarizes our work efforts and presents
our findings in general accordance with the RHRS program and
initial study conducted in 2002. The findings presented in this
report are based on research, field evaluation, and analyses
conducted for this rock slide potential inspections update project.
The findings and recommendations are intended to form the basis for
rockfall remediation prioritization. The findings and
recommendations presented herein are subject to the limitations
noted at the end of this report. 1.2 Project Considerations The
project study area only encompasses the public streets under the
jurisdiction of the City and County of Honolulu on the Island of
Oahu, Hawaii. The City streets considered by this study are those
listed in the Street Index for the Island of Oahu, dated January
1996. Many of the streets owned and/or maintained by the City
traverse steep hillslope areas in and around the ridge and valley
regions of the Island of Oahu. Due to the steep terrain and
location of development in these areas, many of the City streets on
Oahu are below steep natural slopes and man-made cut slopes that
are composed of rock and weathered rock materials. With the passage
of time, erosional forces that work to alter and denude the slope
faces continually affect these slopes. As a result,
the hillslopes are essentially in a slow but constant state of
geologic evolution that may generate potential hazards such as
falling rock, landslide activity, and slope erosion. These
potential hazards can have an adverse effect on development and the
public right-of-ways located below the hillslopes.
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SECTION 1. GENERAL
The rocky hillslopes, which are located adjacent to existing
public right-of-way (City streets), have the potential to generate
falling earth material such as boulders and rock fragments that
could potentially inundate the bounding sidewalk and roadway areas.
There are a number of locations on the Island of Oahu where
rockfall have occurred along City streets and where public
complaints have been received regarding potentially hazardous
falling rock conditions. In addition, there are also many rock
slopes adjacent to City streets where the existing rock
hillslope conditions are presently generally stable but may be
subject to future erosion and potential rockfall hazard. Thus, it
is desired to develop and maintain an inventory of rock hillslope
sites adjacent to City streets that may require remedial
improvements. In addition to maintaining the inventory of rock
hillslope sites, it is desired to prioritize the stabilization of
the more hazardous rockfall sites to reduce the potential hazards.
It is necessary to develop a system to classify and rank the
potential rockfall hazard sites in order to establish a rational
way to categorize and prioritize remedial work. The RHRS was
originally developed in 1984 by the Oregon Department of
Transportation (ODOT) and is now widely recommended by the National
Highway Institute (NHI) as a means for transportation agencies to
address their rockfall hazards proactively. The RHRS is a method to
prioritize the use of limited construction funds by numerically
differentiating the apparent risks at rockfall sites. The RHRS is a
process that allows responsible agencies to actively manage the
rock slopes adjacent to their roadway system. In general, the RHRS
process consists of six stages that build upon each other to
achieve the ultimate objective of assisting the prioritization and
planning of remedial construction work. The six stages of the
program are outlined as follows: 1. 2. 3. 4. 5. 6. Inventory
Preliminary Rating Detailed Rating Preliminary Design and Cost
Estimate Project Identification and Development Review and Database
Update
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SECTION 1. GENERAL
In 2002, Geolabs, Inc. implemented the first four stages of the
Rockfall Hazard Rating System (RHRS) for the City and County of
Honolulu. The rock slide potential database was then developed in
2005 containing the initial stages of the RHRS program, including
inventory, preliminary rating, detailed rating, preliminary design,
and cost estimate. The RHRS program recommends conducting periodic
inspection at
intervals of about 2 to 4 years in order to update the ratings
and reflect the changes of slope conditions, recent
construction/maintenance activities, and escalated construction
cost. This report encompasses the first two stages of this update,
including the inventory and preliminary rating of the potentially
hazardous hillslopes identified in 2002. A more detailed
description of the inventory and preliminary rating stages are
provided later in this report.
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SECTION 1. GENERAL
1.3
Purpose and Scope The purpose of this rock slide potential
inspections project is to update the
existing inventory database and preliminary rating of
potentially hazardous rock slopes to form the basis for future
stages of rockfall evaluation and analyses for remedial
construction planning. Our work was performed in general accordance
with our fee proposal dated March 7, 2007. The general scope of
work for this geotechnical
engineering evaluation included the following tasks and work
efforts: 1. 2. Research and review of available City records
pertaining to past rockfall activity, public complaints, and
reports of rockfall clean-up activity. Research and review of
available map data including the Citys Geographic Information
System (GIS), United States Department of Agriculture Soil
Conservation Service (USDASCS) Soil Survey, United States
Geological Survey (USGS), Tax Map Key maps, and other in-house
resources. Conversion of the Citys GIS map information to AutoCAD
2004 format in support of the preparation of the maps and site
plans for the project. Research and review of available City and
BWS construction as-built drawings to assess the location of the
City property boundary for each hillslope site identified in
support of the determination of probable slope ownership.
Geotechnical and geological engineering evaluation of the field
data to assess preliminary slope rating for each hillslope site
identified. Preparation of monthly memorandum to update the project
progress. Preparation of this report summarizing our work on the
project and presenting our findings. Coordination of our overall
work on the project by our senior project engineer. Quality
assurance of our work and client consultation by our principal
engineer. Miscellaneous work efforts such as drafting, word
processing, and clerical support.
3. 4.
5. 6. 7. 8. 9. 10.
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SECTION 1. GENERAL
This report provides some background information and summarizes
our work performed for the project. This report also includes a
discussion of our findings and recommendations, the updated
hillslope inventory and the preliminary slope ratings for the
project. The Island of Oahu Key Map and a set of Area Maps are also
included for reference of the hillslope locations.
END OF GENERAL
W.O. 4683-20
GEOLABS, INC.Hawaii y California
Page 5
SECTION 1. GENERAL
In 2002, Geolabs, Inc. implemented the first four stages of the
Rockfall Hazard Rating System (RHRS) for the City and County of
Honolulu. The rock slide potential database was then developed in
2005 containing the initial stages of the RHRS program, including
inventory, preliminary rating, detailed rating, preliminary design,
and cost estimate. The RHRS program recommends conducting periodic
inspection at
intervals of about 2 to 4 years in order to update the ratings
and reflect the changes of slope conditions, recent
construction/maintenance activities, and escalated construction
cost. This report encompasses the first two stages of this update,
including the inventory and preliminary rating of the potentially
hazardous hillslopes identified in 2002. A more detailed
description of the inventory and preliminary rating stages are
provided later in this report. 1.3 Purpose and Scope The purpose of
this rock slide potential inspections project is to update the
existing inventory database and preliminary rating of potentially
hazardous rock slopes to form the basis for future stages of
rockfall evaluation and analyses for remedial construction
planning. Our work was performed in general accordance with our fee
proposal dated March 7, 2007. The general scope of work for this
geotechnical
engineering evaluation included the following tasks and work
efforts: 1. 2. Research and review of available City records
pertaining to past rockfall activity, public complaints, and
reports of rockfall clean-up activity. Research and review of
available map data including the Citys Geographic Information
System (GIS), United States Department of Agriculture Soil
Conservation Service (USDASCS) Soil Survey, United States
Geological Survey (USGS), Tax Map Key maps, and other in-house
resources. Conversion of the Citys GIS map information to AutoCAD
2004 format in support of the preparation of the maps and site
plans for the project. Research and review of available City and
BWS construction as-built drawings to assess the location of the
City property boundary for each hillslope site identified in
support of the determination of probable slope ownership.
3. 4.
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SECTION 1. GENERAL
5. 6. 7. 8. 9. 10.
Geotechnical and geological engineering evaluation of the field
data to assess preliminary slope rating for each hillslope site
identified. Preparation of monthly memorandum to update the project
progress. Preparation of this report summarizing our work on the
project and presenting our findings. Coordination of our overall
work on the project by our senior project engineer. Quality
assurance of our work and client consultation by our principal
engineer. Miscellaneous work efforts such as drafting, word
processing, and clerical support.
This report provides some background information and summarizes
our work performed for the project. This report also includes a
discussion of our findings and recommendations, the updated
hillslope inventory and the preliminary slope ratings for the
project. The Island of Oahu Key Map and a set of Area Maps are also
included for reference of the hillslope locations.
END OF GENERAL
W.O. 4683-20
GEOLABS, INC.Hawaii y California
Page 4
SECTION 2. BACKGROUND 2.1 Study Objective The objective of this
Rock Slide Potential Inspections study is to update the initial two
stages of the RHRS established in 2002. The initial two stages of
the RHRS are to: 1. 2. Review and update the existing inventory of
rock hillslopes that are located adjacent to City streets; and,
Conduct a preliminary evaluation and rating update assessment of
the hillslopes contained in the inventory for classification into
three broad categories of potential rockfall hazard (Class A, B, or
C).
The updates reflect geological evolution changes, recent
landslide events, and recent construction/maintenance activities.
The updated rock hillslope inventory and preliminary rating
information (Stages 1 and 2) will be used to conduct site-specific
study, including a detailed evaluation and rating of the most
potentially hazardous hillslopes based on the geologic character of
the hillslope and the existing roadway conditions. For example, we
anticipate that the detailed site assessments should
progress first with the Class A (high) rockfall potential sites
and then be followed by the Class B (moderate) rockfall potential
sites. Class C (low) rockfall potential sites usually do not need
further evaluation. Once the potentially hazardous sites have been
prioritized, additional stages of the RHRS will be implemented to
move forward with the detailed slope rating, the development of
preliminary remedial conceptual designs and construction cost
estimates, and project level identification and development. The
slope ownership may be used to prioritize the rockfall sites in
addition to the numeric ratings by addressing legal and
constructability issues. 2.2 Hillslope Inventory and Preliminary
Rating Method of Study The updates were conducted by re-visiting
the individual slope sites and evaluating, confirming/revising the
RHRS classification on the basis of the current hillslope
condition. During the field reconnaissance, new rock hillslopes may
be
identified, while old rock hillslopes may be removed.
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SECTION 2. BACKGROUND
2.2.1 Hillslopes Applicable to the RHRS Each hillslope site
considered by this RHRS study was subjectively evaluated and judged
whether the existing slope conditions fit some general slope
condition criteria. Based on our review of the overall requirements
of the RHRS, the general slope criteria were established in such a
manner that hillslopes with very low potential rockfall hazard
would not be included in the database. The general slope criteria
that hillslopes should possess in order to be included in the RHRS
consist of the following: x x x x x x x the hillslope should have
at least some potential to produce falling rock that could possibly
reach the roadway; the hillslope should be composed of rock and
weathered rock materials; the hillslope should contain a minimum of
about 25 to 50 percent rock material; the hillslope must be located
adjacent to a City and County roadway; the hillslope should be
greater than about 6 feet in vertical height; the hillslope segment
should be longer than about 30 feet in length; and, the hillslope
should be steeper than about 1H:1V.
Some of the general slope condition criteria were overruled to
allow the hillslope in the RHRS, if one or more of the following
situations were noted: x the hillslope site had been reported by
the City maintenance division to present a hazardous rockfall
condition or maintenance clean-up problem; the hillslope site had
been reported by public complaint as a potential hazardous
condition or problem area; or, the hillslope was evaluated and
judged to present a potentially hazardous falling rock condition
despite not meeting the criteria set forth for inclusion in the
study.
x x
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SECTION 2. BACKGROUND
2.2.2 Hillslope Conditions Excluded from the RHRS Some of the
hillslope conditions encountered in the field that suggested the
removal of the slope from further consideration by the RHRS study
include: x x x x x x rock slopes not adjacent to City and County
roadway; rock slopes adjacent to City and County roadway where
there was no potential for falling rock to affect the public
right-of-way; soil slopes containing fewer than about 25 percent
rock materials; soil slopes (such as residual soil and alluvium)
that experience surface soil erosion; documented landslide and
earth movement problem areas; and, reported drainage and surface
erosion problems involving soil and rock debris not directly
related to a hillslope rockfall condition.
To properly utilize the RHRS methods, future slopes added to the
slope inventory should be carefully reviewed for general adherence
to the established general slope condition criteria. The slope
condition criteria used to determine whether a hillslope should be
included in the RHRS database are outlined in Section 2.2.1.
Surface soil erosion from slopes including the deposition of
hillslope debris resulting from poor drainage should be addressed
by a separate study and database utilizing appropriate rating
system specifically developed to classify erosion and drainage
problems. 2.2.3 Methods of Preliminary Hillslope Evaluation and
Rating The preliminary hillslope evaluation and rating effort
consisted of documenting each rock hillslope site (rockfall
section) that fit the general slope condition criteria for
inclusion in the RHRS database. During the site evaluation, a
standardized
evaluation form describing the general site conditions
pertaining to rockfall and adjacent roadway condition was
completed. General measurements of the slope geometry, GPS
coordinates (latitude and longitude) at the beginning and ending of
each hillslope site, and digital photographs of the site were also
recorded. Finally, the slope was assessed a preliminary subjective
rating of either Class A, B, or W.O. 4683-20 GEOLABS, INC.Hawaii y
California
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SECTION 2. BACKGROUND
C, which corresponds to the perceived level of potential hazard
for rockfall on the adjacent roadway based on the estimated
potential for future rockfall to encroach on the roadway and
historical rockfall accounts. It should be noted that assessment
for the slope ownership was conducted based on the available
as-built construction drawings and Tax Map Key (TMK) records. The
information consisting of approximate location of property boundary
and distance in relation to top of slope or toe of slope were
included in the standardized evaluation form. If no useable
construction as-built drawing is available, additional field
surveying activities will be performed for the boundary location
and slope ownership. The purpose of the preliminary slope rating
was to group the rockfall sections into one of three broad,
manageable sized classes (A, B, or C). Without performing the
preliminary rating, additional time would be spent applying the
detailed rating at sites with only a low-to-moderate potential for
a hazardous condition. The preliminary rating assessment is a
subjective evaluation of rockfall potential that requires
experienced and qualified personnel to make valid judgments based
on facts, observations, and relative comparisons. Qualified
personnel may include those with civil/geotechnical engineering and
geological background. 2.2.4 Preliminary Hillslope Rating We
implemented the following RHRS criteria for use in the preliminary
rating of rockfall sections. The RHRS is a proactive system, which
is primarily aimed at the rockfall potential at a site. Therefore,
the primary controlling element of the
preliminary rating is evaluating the estimated potential for
rockfall on the roadway. Secondarily, the historical rockfall
activity element is used to supplement the preliminary rating,
where clarification is needed. As previously mentioned, the slope
ownership, sometimes, plays a role in prioritizing remedial work.
For example, it is easier to design and construct It is our
remedial work on City owned versus privately owned property.
understanding that public funds can not be utilized for private
matter. The slope W.O. 4683-20 GEOLABS, INC.Hawaii y California
Page 9
SECTION 2. BACKGROUND
ownership information, where there were as-built drawings
available, was included in the database. However, the slope
ownership information was not used to govern the preliminary rating
in the study. The primary controlling element was evaluated on the
basis of field reconnaissance of the hillslope. The secondary
controlling element was evaluated on the basis of a review of
public complaint records and maintenance records. The following
table summarizes the two criteria used to assess the preliminary
slope rating. CRITERIA 1. Estimated Potential for Rockfall on
Roadway 2. Historical Rockfall and Maintenance Activity 2.2.5
Hillslope Site Identification Each City street that contains a
rockfall section was assigned a distinct identification number. The
street identification numbers range from 001 through 122 and
correspond to the number of streets with rock hillslopes addressed
by the study. For streets with only one hillslope location, the
Slope Identification No. (Slope I.D. No.) corresponds to that
particular street identification number. For streets containing
more than one hillslope location (multiple rockfall sections), an
alphabetical suffix was added to the street number to define the
site specific Slope Identification Number. For example, a hillslope
located on a street containing only one slope segment is identified
as Slope I.D. No. 003. For three separate hillslope sites on the
same street, the Slope I.D. Nos. would be 004-A, 004-B, and
004-C.END OF BACKGROUND
A High High
CLASS B Moderate Moderate
C Low Low
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SECTION 3. GEOLOGY 3.1 Regional Geology The Island of Oahu
encompasses approximately 604 square miles of land area that may be
divided into four major geographic provinces. The geographic
provinces include the following: 1) Koolau Mountain Range, 2)
Waianae Mountain Range, 3) Schofield Plateau, and 4) Coastal Plain.
The majority of the Island of Oahu was built by the extrusion of
basaltic lava from two primary shield volcanoes known as Waianae
and Koolau. The older Waianae Volcano is estimated to be middle to
late Pliocene in geochronologic age and forms the bulk of the
western third of the island. The younger Koolau Volcano is
estimated to be late Pliocene to early Pleistocene (Ice Age) in age
and forms the majority of the eastern two-thirds of the island.
Waianae became extinct while Koolau remained active; therefore, the
westward flowing lava from the Koolau Volcano continued to bank
against the weathered products of the Waianae Volcano to create the
elevated area known as the Schofield Plateau, situated between the
two volcanoes. Therefore, the Island of Oahu was formed by
coalescence of the two volcanoes. Following the eruption of the
bulk of the lavas, the coastal areas of Oahu were partially
submerged and emerged cyclically due to large-scale sea-level
fluctuations in response to periods of worldwide glaciation. In
addition to the sea level fluctuations, the island mass was
undergoing a gradual subsidence due to the islands mass and
isostatic adjustment of the earths crust beneath the island. As a
result of the cyclic sea level fluctuations and the gradual
subsidence of the island, the erosional baseline likewise,
fluctuated, and major streams were drowned and buried and later
emerged to renew their incision. The lowering of base level results
in an increased stream gradient and consequently an increased rate
of stream down cutting. The effect of changes in erosional baseline
impact the evolution of landforms by influencing the rate of stream
down cutting and sediment deposition in addition to changing the
coastal exposure to ocean wave erosion. The combined effects are
evidenced by the evolution of steepwalled amphitheater-shaped
valleys; filling of valleys to form broad, gently sloping alluvial
floors; and, the initiation of renewed stream dissection into the
older alluvial W.O. 4683-20 GEOLABS, INC.Hawaii y California
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SECTION 3. GEOLOGY
deposits to form terraces at the bottom of the valley floors.
This cyclic activity during the Pleistocene Age partially accounts
for the present topography of today including the Ewa, Honolulu,
and Kahuku sedimentary coastal plains and the coastal perimeter of
the Island of Oahu. Today, both the Waianae and Koolau Mountains
have lost most of their original shield volcano outline and exist
as elongated mountain ranges that are evolving largely by erosional
processes. The Koolau Range, with its highest peak of about 3,105
feet above sea level, is approximately 37 miles in length and is
deeply incised by active stream cutting and mass wasting processes.
In contrast, the Waianae Range with its highest peak of about 4,025
feet above sea level at Mount Kaala is about 22 miles in length.
The Waianae Range has been carved into large valleys separated with
steep ridgelines by a long history of stream erosion, mass wasting,
and island-wide submergence and re-emergence. 3.2 Geology and
Rockfall Volcanic rock and related weathered volcanic rock products
underlie the bulk of the interior of the Island of Oahu. Steep
hillsides and cut slopes composed of rock and weathered rock
materials occur most commonly at the developed interior portions of
the Island of Oahu. Based on our findings, potentially hazardous
rock slopes that produce falling rock are primarily composed of
layered volcanic products such as basalt rock with clinker
interbeds and volcanic tuff and cinder deposits. Other rock slopes
may be composed of calcareous sandstone, coral reef and limestone
deposits, which are generally at scattered locations around the
perimeter of the Island of Oahu. Rockfall is largely
dependent on the rock quality, which includes the fracture
width, fracture spacing, and other irregularities between the
physical and chemical rock components composing the slope. In
general, rockfall may be generated by relatively unweathered rock
material as well as highly weathered rock material. Extremely
weathered volcanic rock, often
referred to as saprolite, is soft, decomposed rock material that
retains some remnant rock texture but is very friable and may be
crushed to basic soil and rock fragment components. W.O. 4683-20
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SECTION 3. GEOLOGY
experienced judgment must be exercised to estimate whether such
a slope is capable of producing rock fall. 3.2.1 Saprolite/Mixed
Rock Hillslopes Under some conditions, slopes composed of
saprolitic material experience earth movements such as landslide
activity, which may involve a localized block of earth material or
a portion of the hillslope mass. Because there are some
indistinctness between the potential hazard associated with
individual falling rocks and larger landslide earth movements, some
saprolitic slopes that contain a relatively low proportion of rock
materials were included in the slope inventory despite not
exhibiting pure rock slope characteristics. Some of these mixed
saprolitic/rock slopes included in the slope inventory were
observed to have experienced some significant earth movement that
appeared to have potentially affected the public right-of-way. In
addition, some saprolitic slopes were observed to contain remnant
boulders, localized zones of hard rock outcropping, or other earth
material having both soil and rock-like properties. These slopes
were included in the slope inventory since the potential fall of
these materials could be categorized as a rockfall hazard. The
saprolitic slopes that exhibit landslide scars or contain rock-like
components were encountered mainly on the windward side of the
Island of Oahu. Based on our findings, Windward Oahu has a greater
number of slopes that are composed of saprolitic material mixed
with rock. Windward Oahu generally
receives greater rainfall, which tends to accelerate the
physical and chemical weathering processes that are responsible for
the decomposition of rock to saprolitic materials. Thus, a greater
number of slopes in Windward Oahu required inspection to evaluate
the rock/soil materials and associated potential rockfall hazard. A
few slopes included in the inventory are composed of
semi-consolidated older colluvial and alluvial materials. These
soil/rock deposits consist of weathered rock material (cobbles,
boulders, and gravel) partially consolidated in a clayey soil
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SECTION 3. GEOLOGY
matrix.
Despite not being composed entirely of rock material, the
on-going
weathering and erosion of these slopes has the potential to
produce some falling rock. Based on our findings, the slopes with
the greater potential hazard for significant rockfall are those
that are composed of layered basalt rock which contain significant
thickness of highly fractured clinker interbedded with thick layers
of dense basalt rock. In this condition, there exists a wide
disparity in the stability of the materials in the exposed slope
face. The rubbly clinker layers tend to erode faster than the
bounding dense basalt layers thus producing potential instability
in the overhanging blocks of dense rock. The large blocks of dense
basalt rock then have greater capability to fall and roll without
breaking into smaller pieces. 3.3 Geography and Rockfall
Distribution Based on our review of the geographic spread of
potential rockfall sites on the Island of Oahu, some
generalizations may be made regarding the location of rockfall
sites. The overall spread of inventoried hillslopes is shown on the
Island of Oahu Key Map, Plate 1. In general, basalt rock hillslope
exposures with lesser amounts of surface soil were observed to be
predominant in the areas of East Oahu (Hawaii Kai to about Manoa)
and West Oahu. In general, these areas have a drier climate that
supports a slower rate of physical and chemical weathering. Thus,
there is generally greater Furthermore, the slopes
exposure of intact rock material at the ground surface.
encountered in these drier climate areas have generally thinner
surface soil deposits covering the basalt rock formation. Where new
development occurs in hilly terrain of the drier climate areas, the
likelihood of encountering rock material in slope excavations is
generally higher. In contrast, the wetter climate areas of Oahu,
such as Windward Oahu (Kahuku to Waimanalo), and Central Oahu
(Wahiawa) generally have greater surface soil cover and deeper rock
weathering profiles. Therefore, hard rock hillslopes are less
commonly encountered in these areas except in the gulches and
valleys where stream erosion has
W.O. 4683-20
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SECTION 3. GEOLOGY
dissected the landscape. Relatively thick horizons of residual
soil and saprolitic soils are more commonly encountered due to the
greater depth of rock weathering and faster erosion rates. Due to
the typically flatter terrain and topographic relief of Central
Oahu, slope excavation for land development is not as widespread as
other hilly areas of the Island of Oahu. It is noteworthy that a
number of potential rockfall sites located in the District of
Honolulu are located in older neighborhoods where some of the
existing roadway corridors are narrower and steep cut hillslopes
extend closer to the public right-of-way. In addition, many of the
older rock cut slopes were excavated to stand at near-vertical
inclinations, which may tend to decrease slope stability where the
slope face may consist of significant clinker and weak rock layers
that are more susceptible to erosion. Some examples of these
particular conditions include St. Louis Heights and Wilhelmina Rise
areas of Honolulu. In general, the region of Oahu with the highest
concentration of inventoried rock hillslopes is the Honolulu
District due to the high density of development in areas of high
topographic relief, which require significant earthwork and
grading. Other regions of relatively high-density development and
high topographic relief are the Kailua and Kaneohe areas of
Windward Oahu. However, fewer rock hillslopes were inventoried due
to the predominance of soil deposits composing the slopes in these
areas. Other regions of Oahu have a lower concentration of
inventoried slopes due to the lower density of development, lower
topographic relief requiring less intensive earthwork and grading,
and a greater predominance of slopes composed of soil materials.
The general regions of Oahu where a lower number of inventoried
hillslopes exist are: x x x Central Oahu lower relief topography
and thicker soil horizons West Oahu limited development in rocky
areas North Shore limited development in rocky areasEND OF
GEOLOGY
W.O. 4683-20
GEOLABS, INC.Hawaii y California
Page 15
SECTION 4. DISCUSSION AND RECOMMENDATIONS 4.1 Findings This
report provides some background information, summary of our work,
discussion of our findings, and recommendations for the project.
This report also
contains the Island of Oahu Key Map (Plate 1) and the various
Area Maps (Plates 2.1 through 2.22) showing the general location of
the hillslopes as well as summary of the inventory database and the
preliminary slope ratings (Plates 3.1 through 3.7), and summary of
slope ownership assessment and surveying (Plates 4.1 through 4.9).
To further categorize the slope ownership impact, the results of
the slope ownership are divided into four categories as below, and
presented on Plates 5.1 through 5.13. A list of the various plates
that comprise this report submittal is provided in the Closure
section of this report. x x x x Case 1 Slope within City ROW
(property line at or near top of slope) Case 2 Slope partially
within City ROW (property line in middle of slope) Case 3 Slope
outside City ROW (property line at or near toe of slope) Case 4
Combination of Case 1, 2 and/or 3, due to property line varying
across slope site)
Based on the results of the rockslide potential inspections for
the RSRH database update No. 1 for City streets on the Island of
Oahu, one new slope site was identified and added into the
database, while one slope site initially identified in 2002 was
removed from the database due to a private roadway along the toe of
slope. A total of 256 slope sites (rockfall sections) within 122
City streets were observed to have rocky hillslopes that have the
potential to produce falling rock that could encroach on the public
right-of-way. The 256 rockfall sections were then evaluated and
rated as A, or B, or C, and are summarized in the following table.
RHRS Classification A B Initial Database (2002) 56 93 Update No. 1
(2008) 59 93
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SECTION 4. DISCUSSION AND RECOMMENDATIONS
RHRS Classification C Total
Initial Database (2002) 107 256
Update No. 1 (2008) 104 256
The general distribution of the hillslope sites is shown on the
Island of Oahu Key Map, Plate 1. The oversize plan sheets (Area
Maps) show the location of the hillslope sites with respect to the
neighborhood areas located on the Island of Oahu. Furthermore, the
Island of Oahu Key Map shows the boundary delineation of the
various neighborhoods that the Area Maps depict. The locations of
the hillslope sites are identified on the various Area Maps for the
Island of Oahu. The Area Maps are presented on Plates 2.1 through
2.22 of this report. The Area Maps show a more detailed view of the
hillslope site location that is intermediate between the Island of
Oahu Key Map and the individual Site Plans. The inventory updates
are presented on Plates 3.1 through 3.7, which contain Street Name,
Slope I.D. No., Neighborhood Area, updated and original preliminary
ratings, and remarks reflecting changes made in the database. The
inventory updates shown on Plates 3.1 through 3.7 are sorted by the
updated Preliminary Slope Rating and progresses from the Class A
slopes to Class C slopes. 4.1.1 Slope Evaluation and Rating The
findings presented in this report are based on field observations
conducted of the existing conditions observed and measured at the
hillslope sites at the time of our field reconnaissance. The
observations were recorded by qualified personnel who have
experience in the systematic evaluation of geologic conditions
pertaining to potential falling rock hazards and hillslope
stability in general accordance with the RHRS program. It should be
noted that only qualified and experienced personnel using a
standardized form for recording observations should conduct the
slope evaluation and rating. The person(s) conducting future slope
evaluation and rating work should be thoroughly familiar with the
Method of Study criteria outlined in Section 2.2 and Section 4.1 of
this report.
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Page 17
SECTION 4. DISCUSSION AND RECOMMENDATIONS
As mentioned previously, the key to assessing whether a
hillslope should be classified as Class A, B, or C resides with
evaluating the primary controlling element of the estimated
potential for rockfall on the roadway. Secondarily, the historical
rockfall activity element is used to supplement the preliminary
rating where additional clarification may be needed. The slope
ratings are based in part on our geological interpretation of the
existing site conditions observed at the time of our site visit. In
order to conduct the
preliminary slope ratings, some professional judgments were made
pertaining to the geologic conditions and possible path of falling
rock with respect to the public right-of-way. The same personnel
conducted the slope evaluations in an effort to maintain
objectivity and consistency. The preliminary slope evaluation and
rating considered the subjects of observation and measurement noted
on the standardized evaluation form and also included an overall
judgment of the relation of each slope condition to the context of
the study as a whole. 4.1.2 Rockfall Incident Reports by
Maintenance Division During the initial development of the RHRS
inventory, public complaints and reports by the maintenance
division were gathered. The list of existing trouble areas
(frequent clean-up of debris) and potential trouble areas
(appearance of unstable slope conditions) were generated and
included in the original RHRS database report, dated March 14,
2002. To standardize the records of landslide/rockfall events and
maintenance activities, a Rockfall Hazard Incident Report form was
developed during the initial RHRS database development and
distributed to the Department of Maintenance. A total of four
incident reports were received and summarized as the following.
Date of Report 9/15/06 11/8/06 Location of Incident Beach Road
Auloa Road Approx. Slope ID No. 054 112-B Preliminary Rating A A
Classification of Incident Rockfall Shallow Landslide
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Page 18
SECTION 4. DISCUSSION AND RECOMMENDATIONS
Date of Report 12/31/07 5/23/08
Location of Incident Pupukea Road Moanalua Loop
Approx. Slope ID No. 099 085
Preliminary Rating A A
Classification of Incident Rockfall Rockfall
Information from the above rockfall incident reports was used in
this project and considered in the preliminary slope rating
evaluation. The information should also be used in the detailed
rating stage to quantify the potential rockfall volume and to
assist with prioritizing hazardous rockfall potential. 4.1.3
Hillslope Ownership Assessment To address the Citys legal and
constructability issues, additional research for the slope
ownership was conducted. The research was based on available City
and BWS construction as-built topographic survey drawings.
ControlPoint Surveying, Inc. performed the study. The research
results are summarized on Plates 4.1 through 4.7 for each hillslope
site evaluated. Useable construction as-built drawings were located
for 183 hillslope sites, however, no useable as-built information
were found for 73 remaining hillslope sites (19 A slopes, 31 B
slopes and 23 C slopes). Actual field surveying was further
performed for 19 A and 31 B slope sites where useable construction
as-built drawings were not available, to assess the City streets
right-of-way boundary in relation to the hillslope sites. The field
surveying results are also summarized on Plates 4.1 through 4.7.
Field surveying may be performed for the remaining 23 C slopes, for
which no useable as-built drawings are available, to complete the
hillslope ownership assessment, when additional funding becomes
available. To assist prioritization of rockfall mitigation project
solicitation, the results of the slope ownership assessment and
field surveying are also presented in the order of the slope
ownership categories (Case 1 through Case 4) in conjunction with
the
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Page 19
SECTION 4. DISCUSSION AND RECOMMENDATIONS
slope ratings (A, B and C) on Plates 5.1 through 5.13, and
summarized in the table below. BREAKDOWN OF SLOPE OWNERSHIP Slope
Ownership Category Slope within City ROW Slope partially within
City ROW Slope outside City ROW Inconclusive 4.2 Recommendations As
mentioned previously, the purpose of this report is to present the
inventory update of hillslopes and the results of the preliminary
slope evaluation and rating revision. The information will be
utilized to support Stages 3 and 4 of the RHRS Case 1 Case 2
Combinations Case 3 A 8 10 20 20 1 B 10 13 30 37 3 C 8 9 5 60
22
program updates. Stages 3 and 4 of the RHRS program consist of
the updates of the detailed slope evaluation and rating (Stage 3)
and the preliminary conceptual designs and cost estimates (Stage
4). At Stages 3 and 4, a large amount of detailed numeric
information is generated about the location and condition of
rockfall sites. We believe that the inventoried hillslopes assessed
a Class A rating (estimated high potential for rockfall on the
roadway) should be advanced to at least Stages 3 and 4 of the RHRS,
similar to the evaluation conducted in 2003 as shown in Appendix
Summary A Slope Detail Rating for reference. We understand that
some of the A slopes rated in 2002 are in the process of rockfall
remedial design, which may be classified as Stage 5 of the RHRS -
Project Identification and Development. We
anticipate that additional A slopes may be identified for
rockfall remedial design after completion of this update, when
additional funding becomes available. This current database update
for rockslide potential inspection is considered Stage 6 of the
RHRS. Based on the results of the updates, the preliminary slope
ratings
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SECTION 4. DISCUSSION AND RECOMMENDATIONS
for some of the hillslope sites were either upgraded from lower
rank to higher rank, or downgraded from higher rank to lower rank.
These updates will result in changes of rockfall remediation
prioritization. We believe that the efforts of these updates will
assist in the planning of the rockfall remediation project
effectively and efficiently with respect to the relative hazardous
potential on public right-of-way. We believe that it is important
to continue the update program at intervals between about 2 to 4
years to incorporate and reflect changes that may have affected the
subject hillslopes with the passage of time. New slope construction
should be
added to the database and existing site modifications should be
reviewed to evaluate whether changes in the current ratings or
slope designs are warranted. Furthermore, cost estimates may be
revised to reflect possible changes in unit bid prices. Conditions
in nature may change unexpectedly and without warning or develop
slowly with the passage of time. Thus, the effects of severe
weather events, seismic activity, and new development may cause
changes in the slope conditions. The
potential for rockfall may either increase or decrease in
response to environmental and man-made changes. Not all changes
that affect a hillslope are pronounced. Reviewing earlier
photographs of the site may best identify subtle changes that occur
over the passage of time. In any case, the review process should be
on-going to protect the initial investment made in the RHRS.
END OF DISCUSSION AND RECOMMENDATIONS
W.O. 4683-20
GEOLABS, INC.Hawaii y California
Page 21
SECTION 5. LIMITATIONS The analyses and recommendations
submitted in this report are based in part upon information
obtained from research and use of available information and site
visual observations. Variations of hillslope conditions between and
beyond our
observations may occur, and the nature and extent of these
variations may not become evident until additional site evaluation
or construction is underway. If variations then appear evident,
Geolabs should be contacted to re-evaluate the recommendations
presented in this report. The locations of the hillslope sites
(rockfall sections) are approximate, having been estimated by
taping from property corner reference points and visible features
shown on the available Tax Key Maps obtained from the Citys GIS
information database. The physical locations of the hillslope sites
should be considered accurate only to the degree implied by the
methods used. The site visual observations, which form the basis of
the preliminary slope evaluations and ratings shown on the
Preliminary Slope Evaluation and Rating Form, depict the general
surface slope conditions observed at the time of our site visit;
thus, some difference in site observations may be anticipated
during site visits made at other times. The preliminary field slope
evaluation and rating was performed using subjective observations
by experienced personnel. In addition, professional judgment was
used to evaluate the existing site conditions and erosional
processes observed. The field data has been reviewed and
interpretations made in the formulation of this report. This report
has been prepared for the exclusive use of the City and County of
Honolulu, Department of Design and Construction for specific
application to the Rock Slide Potential Inspections project in
accordance with generally accepted geotechnical engineering
principles and practices. No warranty is expressed or implied. This
report has been prepared solely for the purpose of developing a
hillslope inventory and preliminary slope classification in general
accordance with the Rockfall Hazard Rating System (RHRS) for the
preliminary evaluation of rockfall hazards for City streets on the
Island of Oahu. Therefore, this report may not contain sufficient
data, or W.O. 4683-20 GEOLABS, INC.Hawaii y California
Page 22
SECTION 5. LIMITATIONS
the proper information, to serve as the basis for preparation of
construction cost estimates nor for bidding purposes. A contractor
wishing to bid on this project should retain a competent
geotechnical engineer to assist in the interpretation of this
report and/or in the performance of additional site-specific
exploration for bid estimating purposes. The owner/client should be
aware that unanticipated soil/rock conditions are commonly
encountered. Unforeseen conditions, such as hillslope evolution,
inactive
landslides, variable groundwater conditions, soft deposits, hard
layers or cavities, may occur in localized areas and may require
additional evaluation or corrections in the field.
END OF LIMITATIONS
W.O. 4683-20
GEOLABS, INC.Hawaii y California
Page 23
PLATES
Slope Inventory and Preliminary Classification Phase III - Rock
Slide Potential Inspections Rockfall Hazard Rating System Database
Update No. 1 Project No. 01154 Island of Oahu, HawaiiPreliminary
Slope Rating Update No. 1 Original A A A A A A B A A A B B Private
Private Private Private Private Private Ownership of Abutting
Property Line Remarks
City Street Name
Slope I.D. No.
Neighborhood Area of Oahu
Kaluanui Road Kaluanui Road Kaluanui Road Kalihiwai Place
Kamookoa Place Anolani Street
014-A 014-E 014-F 015 016-A 031-A
Mariners Ridge Mariners Ridge Mariners Ridge Mariners Ridge
Mariners Ridge Niu Valley
Preliminary rating updated to reflect inclusion of natural rock
slope above the cut slope. CRM retaining wall at slope toe was
extended approximately 15 feet to south. 014-E-1 and 014-E-2 are
now combined to comprise 014-E. 014-F-1 and 014-F-2 are now
combined to comprise 014-F. Slope length is reduced from 270 to 230
feet due to new retaining wall construction. Updated site plan.
Preliminary rating updated to reflect observed loose boulders at
top half of slope. Preliminary rating updated to reflect inclusion
of natural rock slope above the cut slope. Slope length increased
from 150 to 275 feet due to active rockfall. New slope was observed
and assessed as a high potential hazard due to site condition and
history of rockfall events. High upper natural slopes above cut
slope contributed to potential hazard.
Active rockfall and stone/cobble rolled across street in
driveway. Slope length increased from 1,150 feet to 1,630 feet
including portion of Slope ID 053-F. Updated site plan. Deep slope
undercut actively failing with high potential for blocks to reach
roadway.
Slope length increased from 325 feet to365 feet. Updated site
plan. Updated site plan. Slope length of about 1,500 feet.
Collapsed driveway of 1416 Roundtop Dr. on downslope side of road
was observed. Active rockfall was evident by rock slabs and
boulders at slope toe. Upgraded from "B" to "A" due to active
rockfall and loose rock hanging by tree roots.
Upgraded from "B" to "A" due to active rockfall and loose rock
hanging by tree roots. Upgraded from "B" to "A" due to active
rockfall and curve with sloping roadway conditions. Recent rockfall
activities visible from debris and fresh scars. Increased slope
length from 140 feet to 235 feet.
Resident of Parcel 066 reported rolling rock hitting the fence
and upper slope cleaning efforts last year. Upgraded from "C" to
"A" due to substantial active rockslide within Parcel 106. Reduced
slope length to 187 feet due to recent roadway improvements
project. Updated site plan.
Anolani Street Poola Street Poola Street Laukahi Street Halekoa
Drive Koko Drive Sierra Drive Poka Place Diamond Head Road Beach
Road Alencastre Street Dole Street Round Top Drive Round Top Drive
Round Top Drive Round Top Drive Tantalus Drive Makiki Heights Drive
Prospect Street Puowaina Drive Puowaina Drive Hookui Street
Auwaiolimu Street Pacific Heights Road Pacific Heights Road Nuuanu
Pali Drive Alewa Drive Ala Mahamoe Street Ala Lani Street Hulakui
Drive Salt Lake Boulevard Salt Lake Boulevard Salt Lake Boulevard
Aiea Heights Drive Aiea Heights Drive A A A A A A A A A A A A A A A
A A A A A A A A A A A A A A A A A A A A New A A A A A A A A A A A A
A A A A B A A B B A A A A A A C A A A A A A Private Private Private
City / Private Private Private Private State Federal State Private
Private State State State Private / State State State Federal
Private / State Private State State Private Private Private Private
Private Private Private Private Private Private Private Private
031-B 036-B 036-C 037-A 045-B 048-A 050 052 053-E 054 058 061-A
062-K 062-N 062-P 062-Q 062-T 064-B 066-B 067-A 067-C 068 069-B
070-D 070-G 072-C 073 075-E 078 080-D 081-B 081-D 081-E 083-A
083-B
Niu Valley Waialae Iki Waialae Iki Waialae Iki Waialae Nui
Wilhemina Rise Wilhemina Rise Diamond Head Diamond Head Diamond
Head St. Louis Heights Manoa Tantalus Tantalus Tantalus Tantalus
Tantalus Tantalus Punchbowl Punchbowl Punchbowl Punchbowl Punchbowl
Pacific Heights Pacific Heights Nuuanu Alewa Heights Moanalua
Moanalua Valley Salt Lake Salt Lake Salt Lake Salt Lake Aiea
Heights Aiea Heights
Landslide scars on downslope side of road (opposite slope
segments) exposed existing guardrail posts.
W.O. 4683-20
GEOLABS, INC.
NOVEMBER 2012
PLATE 3.1
Slope Inventory and Preliminary Classification Phase III - Rock
Slide Potential Inspections Rockfall Hazard Rating System Database
Update No. 1 Project No. 01154 Island of Oahu, HawaiiPreliminary
Slope Rating Update No. 1 Original Ownership of Abutting Property
Line Remarks
City Street Name
Slope I.D. No.
Neighborhood Area of Oahu
Updated length of slope to 1795 feet. Updated site plan. Few
trees nearly lost bottom support due to active erosion/rockfall.
Few trees nearly lost bottom support due to active
erosion/rockfall.
Updated slope length to 960 feet. Updated site plan. Recent
landslide visible. Recent landslide visible. Recent landslide
visible. Most of slope was covered by grass and trees compared to
bare slope in 2001. The recent landslide failure wedge needed an
immediate attention. Updated slope length to 380 feet. Updated site
plan.
Naupaka hedge planted along slope toe may be a less-costly and
effective mitigation. Space available for planting slope toe hedge.
Preliminary rating updated due to observed active rock erosion.
Moanalua Loop Komo Mai Drive Komo Mai Drive Waihona Street
Waihona Street Waihona Street Pupukea Road Maunawili Road Maunawili
Road Maunawili Road Auloa Road Auloa Road Auloa Road Old
Kalanianaole Road Old Kalanianaole Road Old Kalanianaole Road Old
Kalanianaole Road Alala Road Mokuhano Street Hawaii Kai Drive
Kamehame Drive Hoahana Place Waihili Place Hanohano Place Hanauma
Bay Road Polihale Place Kaluanui Road Kaluanui Road Kaluanui Road
Kaluanui Road Kamoi Place Kaahue Street Uwao Street
085 088-A 088-C 089-A 089-C 089-D 099 111-A 111-C 111-D 112-A
112-B 112-D 114-A 114-B 114-C 114-E 121 001 004-D 005-B 006 007 008
011 012 014-B 014-C 014-G 014-H 022 023 030
Aiea Pearl City Uplands Pearl City Uplands Waiawa Waiawa Waiawa
Pupukea Maunawili Maunawili Maunawili Maunawili Maunawili Maunawili
Olomana Olomana Olomana Olomana Lanikai Kalama Valley Hawaii Kai
Kamehame Ridge Kamehame Ridge Kamehame Ridge Kamehame Ridge Hawaii
Kai Portlock Mariners Ridge Mariners Ridge Mariners Ridge Mariners
Ridge Mariners Ridge Mariners Ridge Hahaione Valley
A A A A A A A A A A A A A A A A A A B B B B B B B B B B B B B B
B
A A A A A A A A A A A A A A A A A A B B B B C B B B B B B B B B
B
Private Private Private State State Private Private / State
Private Private Private Private Private Private State / Private
Private Private Private State / Private Private City / Private
Private Private Private Private City Private Private Private
Private Private Private Private Private
Many fallen cobbles along sidewalk and slope toe. Vegetation was
maturing and providing more buffer to erosion and control of
falling rock. Series of CRM walls were observed on upper slope,
while lower cut slope with thick seasonal vegetation and greenwaste
disposal.
Slope length was reduced from 130 to 120 feet due to upper
retaining wall repair and new lower retaining wall construction
covering old landslide site. Updated site plan. Preliminary rating
updated to reflect loose stacked boulders and separating blocks
from cut slope face.
Kainoa Place Kamole Street Luinakoa Street Halekoa Drive Halekoa
Drive Wahinekoa Place Malu Place Koko Drive
033 038-B 044 045-A 045-C 046 047 048-C
Wailupe Valley Waialae Iki Waialae Nui Waialae Nui Waialae Nui
Waialae Nui Waialae Nui Wilhemina Rise
B B B B B B B B
B C B B B B B B
Private Private Private Private Private Private Private City
W.O. 4683-20
GEOLABS, INC.
NOVEMBER 2012
PLATE 3.2
Slope Inventory and Preliminary Classification Phase III - Rock
Slide Potential Inspections Rockfall Hazard Rating System Database
Update No. 1 Project No. 01154 Island of Oahu, HawaiiPreliminary
Slope Rating Update No. 1 Original Ownership of Abutting Property
Line Preliminary rating updated due to many loose cobbles with no
catchment. Remarks
City Street Name
Slope I.D. No.
Neighborhood Area of Oahu
Preliminary rating updated due to instability on high portion of
slope. Preliminary rating updated due to active rockfall from upper
slope.
Slope length increased from 116 to 176 feet including parcel
095. Updated site plan.
Slope length increased from 355 to 555 feet. Updated site
plan.
Iwi Way - Short Lane Iwi Way Koko Head Avenue Koko Head Avenue
Diamond Head Road Diamond Head Road Diamond Head Road Lai Road Lai
Road St. Louis Drive St. Louis Drive St. Louis Drive St. Louis
Drive Robert Place Dole Street Dole Street Round Top Drive Round
Top Drive Round Top Drive Round Top Drive Round Top Drive Round Top
Drive Slope length increased from 950 to 1,630 feet. Updated site
plan.
049-A 049-B 051-A 051-B 053-A 053-C 053-D 056-A 056-B 057-A
057-C 057-D 057-E 060 061-B 061-C 062-A 062-C 062-D 062-E 062-F
062-G
Maunalani Heights Maunalani Heights Kaimuki Kaimuki Diamond Head
Diamond Head Diamond Head Palolo Valley Palolo Valley St. Louis
Heights St. Louis Heights St. Louis Heights St. Louis Heights St.
Louis Heights Manoa Manoa Tantalus Tantalus Tantalus Tantalus
Tantalus Tantalus
B B B B B B B B B B B B B B B B B B B B B B
B C B B B C C B B B B B B B B B B B B B B C
Private Private Private Private Private Private State Private
Private Private Private Private Private Private State / City State
Private Private Private State State State
Preliminary rating updated due to talus accumulation taking away
shoulder and length reduced from 800 to 292 feet due to recent
construction. Updated site plan. Updated site plan. Updated site
plan. Revised slope length from 1,500 to 2,200 feet including
continuous slope segments. Updated site plan.
Round Top Drive Round Top Drive Round Top Drive Tantalus Drive
Tantalus Drive Prospect Street Prospect Street Puowaina Drive
Auwaiolimu Street
062-I 062-M 062-O 062-R 062-S 066-A 066-E 067-B 069-A
Tantalus Tantalus Tantalus Tantalus Tantalus Punchbowl Punchbowl
Punchbowl Punchbowl
B B B B B B B B B
B B B B B B B B B
Upgraded from "C" to "B" due to active rockfall, but existing
swale as catchment. Increased slope length from 150 to 290 feet.
Reduced slope length from 410 to 290 feet. Upgraded from "C" to "B"
due to visible loose rocks and overhanging block. Increased slope
length from 120 to 150 feet. Updated site plan.
Pacific Heights Road Pacific Heights Road Pacific Heights Road
Pacific Heights Road Pacific Heights Road B B B B B B B B B B B B B
Private Private Private Private C B B B C
070-A 070-B 070-C 070-F 070-H
Pacific Heights Pacific Heights Pacific Heights Pacific Heights
Pacific Heights
State State State State / Private State Private Private Private
Private (south) State (north) Private Private Private Private
Private
Pacific Heights Road Nuuanu Pali Drive Nuuanu Pali Drive Anuu
Place
070-J 072-A 072-B 074
Pacific Heights Nuuanu Nuuanu Kalihi Valley
W.O. 4683-20
GEOLABS, INC.
NOVEMBER 2012
PLATE 3.3
Slope Inventory and Preliminary Classification Phase III - Rock
Slide Potential Inspections Rockfall Hazard Rating System Database
Update No. 1 Project No. 01154 Island of Oahu, HawaiiPreliminary
Slope Rating Update No. 1 Original Ownership of Abutting Property
Line Remarks
City Street Name
Slope I.D. No.
Neighborhood Area of Oahu
Reduced slope length from 320 to 218 feet due to recent
development. Updated site plan.
Increased slope length to 282 feet to include flatter but less
catchment slope. Updated site plan.
Increased slope length from 250 to 280 feet. Updated site plan.
Downgraded to "B" due to recently installed chain link fence
retaining most of debris. Downgraded to "B" due to reduced slope
length only including portion along C&C roadway, lower slope
height and available catch areas. Updated site plan. Downgraded to
"B" due to low hazard potential from smaller size of rockfall.
Ala Mahamoe Street Mahiole Street Ala Napuanani Street Hulakui
Drive Hulakui Drive Halawa Heights Road Kilinoe Street Komo Mai
Drive Waihona Street Kaukama Road Mailiilii Road Waianae Valley
Road Haleahi Road Wainihi Street Alapio Road Pulama Road
075-C 077 079 080-B 080-C 082-B 086 088-B 089-B 092 093 095-B
096 098 100 103-B
Moanalua Maonalua Salt Lake Salt Lake Salt Lake Halawa Heights
Pearlridge Pearl City Uplands Waiawa Maili Maili Waianae Waianae
Valley Wahiawa Pupukea Kahaluu
B B B B B B B B B B B B B B B B
B B B B B B B B B B B B B A B A
Private Private Private Private Private Private Private Private
State Private State Private Private / State Private Private
Private
Updated slope length to 870 feet. Updated site plan. Decreased
slope length from 1000 to 800 feet due to recent development.
Updated site plan. Few trees nearly lost bottom support due to
active erosion/rockfall. Slope is nearly completely covered by
grass and trees compared to only some cover in 2001. More talus
accumulation at slope toe compared to wider catchment in 2001.
Upgraded from "C" to "B" due to constant landslide/erosion and
catchment deficiency. Overgrown grass and talus accumulation
encroached into sidewalk. Updated slope length to 755 feet. Updated
site plan. Updated slope length to 110 feet. Updated site plan.
Ahilama Road Ahilama Road Kamehameha Highway Kamehameha Highway
Lilipuna Road Kaneohe Bay Drive Kaneohe Bay Drive Maunawili Road
Auloa Road Old Kalanianaole Road Old Kalanianaole Road Old
Kalanianaole Road Auwaiku Street Lapa Place Honokahua Street
Oilipuu Place Hawaii Kai Drive Hawaii Kai Drive Hawaii Kai Drive
Kamehame Drive Hoolako Place Koko Head Park Road Lumahai Place
Kaluanui Road Kamookoa Place B B B B B B B B B B B B B B C C C C C
C C C C C C A B B B B B B B B B B C B B C C C C C B C C C C C
Private Private Private State Private Private Private Private
Private Private Private Private Private Private Private Private
Private Private City / Private Private Private City Private Private
Private
104-A 104-B 106-B 106-D 108-A 110-A 110-B 111-B 112-C 114-D
114-F 114-H 117 122 002 003 004-A 004-B 004-C 005-A 009 010 013
014-D 016-B
Kahaluu Kahaluu Heeia Kea Heeia Kea Heeia Keaalu Keaalu
Maunawili Maunawili Olomana Olomana Olomana Keolu Hills Lanikai
Kalama Valley Kalama Valley Hawaii Kai Hawaii Kai Hawaii Kai
Kamehame Ridge Kamehame Ridge Hawaii Kai Portlock Mariners Ridge
Mariners Ridge
Slope length reduced due to house lot developments. Updated site
plan. Slope length reduced due to observed rock catchment areas.
Updated site plan. Preliminary rating updated due to permanent
landscape planting with irrigation.
W.O. 4683-20
GEOLABS, INC.
NOVEMBER 2012
PLATE 3.4
Slope Inventory and Preliminary Classification Phase III - Rock
Slide Potential Inspections Rockfall Hazard Rating System Database
Update No. 1 Project No. 01154 Island of Oahu, HawaiiPreliminary
Slope Rating Update No. 1 Original Ownership of Abutting Property
Line Remarks
City Street Name
Slope I.D. No.
Neighborhood Area of Oahu
Some failure of GRP facing caused by small tree growth
protruding through GRP. Minimal potential for rockfall encroachment
at road because of low slope height. Minimal potential for rockfall
encroachment at roadway due to landscape planting and available
roadside catchment. Added a slope segment at Parcel 051 measuring
about 58 feet long, previously obscured by vegetation. Updated site
plan. Accumulation of debris in catchment zone reduced catchment
effectiveness. Increased slope length from 215 to 300 feet. Updated
site plan. Landscape area needed cleaning to remove sloping
soil/rock debris accumulation.
Slope length reduced from 220 to 140 feet due to new house and
retaining wall construction. Updated site plan. Slope length
reduced from 80 to 55 feet due to new house developments. Updated
site plan. Slope site was under remedial development. Final slope
conditions were unknown.
Slope length increased from 55 to 103 feet including Parcel 054.
Updated site plan.
Preliminary rating updated due to limited visible loose
rock.
Slope length reduced from 880 to 525 feet. Updated site
plan.
Slope length reduced from 150 to 100' feet excluding Parcel 014.
Updated site plan.
Kamookoa Place Kaloaloa Street Kawaiki Place Kauku Place Kapoho
Place Kapapala Place Kakiwa Place Kaipuhaa Place Kahuwai Place
Kahauloa Place Kaluanui Place Hokulani Street Hoana Place Mona
Street Ahuwale Street Poola Street Poola Street Poola Street
Laukahi Street Laukahi Street Kamole Street Ehupua Place Ohialoke
Street Hoaaina Place Ihiloa Loop Ihiloa Loop Ihiloa Loop Kihi
Street Koko Drive Diamond Head Road Diamond Head Road Narcissus
Place St. Louis Drive Oswald Street Round Top Drive Round Top Drive
Round Top Drive Round Top Drive Aina Lani Place/Way Makiki Heights
Drive Makiki Heights Drive Mott-Smith Drive Increased slope length
from 420 to 540 feet including Parcel 002. Updated site plan.
Reduced slope length from 90 to 42 feet excluding Parcel 009.
Updated site plan.
016-C 017 018 019 020 021 024 025 026 027 028 029 032 034 035
036-A 036-D 036-E 037-B 037-C 038-A 039 040 041 042-A 042-B 042-C
043 048-B 053-B 053-F 055 057-B 059 062-B 062-H 062-J 062-L 063
064-A 064-C 065
Mariners Ridge Mariners Ridge Mariners Ridge Mariners Ridge
Mariners Ridge Mariners Ridge Mariners Ridge Mariners Ridge
Mariners Ridge Mariners Ridge Mariners Ridge Hahaione Valley
Wailupe Valley Wailupe Valley Wailupe Valley Waialae Iki Waialae
Iki Waialae Iki Waialae Iki Waialae Iki Waialae Iki Waialae Iki
Waialae Iki Waialae Iki Waialae Iki Waialae Iki Waialae Iki Waialae
Iki Wilhemina Rise Diamond Head Diamond Head Palolo Valley St.
Louis Heights St. Louis Heights Tantalus Tantalus Tantalus Tantalus
Makiki Tantalus Tantalus Makiki
C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C
C C C C C C C C C C
C C C C C C C C C C C C C C C C C C C C C C C C B C C C C C C C
C C C C C C C C C C
Private Private Private Private Private Private Private Private
Private Private Private Private Private City Private Private
Private Private Private Private City Private Private Private City
Private Private Private N/A N/A State / Private City Private
Private N/A N/A N/A N/A Private N/A N/A N/A
Slope length reduced from 80 to 74 feet. Updated site plan.
Combine Aina Lani Place and Aina Lani Way including two short
segments with increasing slope length from 580 to 670 feet. Updated
site plan.
W.O. 4683-20
GEOLABS, INC.
NOVEMBER 2012
PLATE 3.5
Slope Inventory and Preliminary Classification Phase III - Rock
Slide Potential Inspections Rockfall Hazard Rating System Database
Update No. 1 Project No. 01154 Island of Oahu, HawaiiPreliminary
Slope Rating Update No. 1 Original Ownership of Abutting Property
Line Remarks
City Street Name
Slope I.D. No.
Neighborhood Area of Oahu
Increased slope length from 170 to 185 feet. Updated site plan.
Increased slope length from 370 to 400 feet. Updated site plan.
Increased slope length from 550 to 660 feet. Updated site plan.
Increased slope length consisting of 212 feet western side and
140 feet eastern side due to recent roadway widening project.
Updated site plan.
Recent slope erosion control implementation with installing
irrigation system and removal of small trees Downgraded to "C" due
to recent rockfall mitigation project including installation of
draped wire mesh and chain link barrier. Recent rockfall mitigation
project installing draped wire mesh and chain link barrier.
Downgraded to "C" due to recent rockfall mitigation project
including installation of draped wire mesh and chain link barrier.
Downgraded to "C" due to available catchment areas and boulder
stacking barrier. Increased slope length from 610 to 640 feet.
Updated site plan. Decreased slope length from 460 to 320 feet.
Updated site plan. Updated length of slope to 525 feet. Updated
site plan. Reduced slope length to 118 feet due to recent
development. Updated site plan. Updated length of slope to 120
feet. Updated site plan. Updated length of slope to 360 feet.
Updated site plan. Downgraded to "C" due to recently constructed
concrete toe wall along slope toe. Deceased slope length to 245
feet. Updated site plan.
Prospect Street Prospect Street Auwaiolimu Street Pacific
Heights Road Pacific Heights Road Pacific Heights Road Von Hamm
Place Nuuanu Pali Drive Ala Mahamoe Street Ala Mahamoe Street Ala
Mahamoe Street Ala Mahamoe Street Haku Street Hulakui Drive Salt
Lake Boulevard Salt Lake Boulevard Salt Lake Boulevard Salt Lake
Boulevard Salt Lake Boulevard Salt Lake Boulevard Halawa Heights
Road Moanalua Road Kaahele Street Komo Mai Drive Komo Mai Drive
Komo Mai Drive Waipahu Street Lumipolu Street Lualualei Hmstd. Road
Waianae Valley Road Kaneaki Street Anemoku Street Hauula Homestead
Road Hauula Homestead Road Hauula Homestead Road Ahuimanu Road
Kamehameha Highway Kamehameha Highway C C C C C C Private Private
Private
066-C 066-D 069-C 070-E 070-I 070-K 071 072-D 075-A 075-B 075-D
075-F 076 080-A 081-A 081-C 081-F 081-G 081-H 081-I 082-A 084 087
088-D 088-E 088-F 090 091 094 095-A 097 101 102-A 102-B 102-C 105
106-A 106-C
Punchbowl Punchbowl Punchbowl Pacific Heights Pacific Heights
Pacific Heights Pacific Heights Nuuanu Moanalua Moanalua Moanalua
Moanalua Moanalua Salt Lake Salt Lake Salt Lake Salt Lake Salt Lake
Salt Lake Salt Lake Halawa Heights Aiea Waiau Pearl City Uplands
Pearl City Uplands Pearl City Uplands Waipahu Waipio Waianae
Waianae Waianae Valley Laie Hauula Hauula Hauula Kahaluu Heeia Kea
Heeia Kea
C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C
C C C C C C
C C C C C C C C C C C C C C C C C C C C C C C A C A B C C C C C
C C C C C B
Private Private N/A N/A N/A N/A Private N/A Private Private
Private Private Private Private N/A Federal Federal Federal Federal
Federal N/A City / Private City State / Private State State N/A
Private N/A Private State Private Private Private Private Private
N/A Private
Lulani Street Lulani Street Lilipuna Road
107-A 107-B 108-B
Heeia Kea Heeia Kea Heeia
Updated slope length to 463 feet. Updated site plan.
W.O. 4683-20
GEOLABS, INC.
NOVEMBER 2012
PLATE 3.6
Slope Inventory and Preliminary Classification Phase III - Rock
Slide Potential Inspections Rockfall Hazard Rating System Database
Update No. 1 Project No. 01154 Island of Oahu, HawaiiPreliminary
Slope Rating Update No. 1 Original Ownership of Abutting Property
Line N/A Private N/A Private N/A Private Private Private Private
Private Updated slope length to 516 feet. Updated site plan.
Updated slope length to 420 feet. Updated site plan. Removed from
database due to being in private roadway. Remarks
City Street Name
Slope I.D. No. C C C C C C C C C C B C C C C C C C C C B
Neighborhood Area of Oahu
Kokokahi Place Auloa Road Ulukahiki Street Old Kalanianaole Road
Old Kalanianaole Road Akiohala Street Aupapaohe Street Kuuna Street
Apokula Street Apokula Place
109 112-E 113 114-G 114-I 115 116 118 119 120
Kokokahi Maunawili Pohakupu Olomana Olomana Enchanted Lake Keolu
Hills Keolu Hills Keolu Hills Keolu Hills
Updated slope length to 310 feet. Updated site plan. Updated
slope length to 367 feet. Updated site plan. Updated slope length
to 40 feet. Updated site plan. Illegal disposal construction
material encroached into cul-de-sac road. Updated slope length to
70 feet. Updated site plan. Downgraded to "C" due to graded rock
slope, available catchment and cut slope benches. Updated slope
length to 35 feet. Updated site plan.
Pulama Road
103-A
Kahaluu
W.O. 4683-20
GEOLABS, INC.
NOVEMBER 2012
PLATE 3.7
Summary of Slope Ownership Assessment Phase III - Rock Slide
Potential Inspections Rockfall Hazard Rating System Database Update
No. 1 Project No. 01154 Island of Oahu, HawaiiUpdated Preliminary
Rating Property Line Location (P/L) 3-9-010: 001 (Pvt) (C-06358
Shts 3, 2 (Typ Rdwy Sec)) 3-9-104: 004 (Pvt) (85-024P Shts 8A, 3
(Typ Rdwy Sec)) 3-9-010: 001 (Pvt) (C-07128 Shts 14, 6 (Typ Rdwy
Sec)) 3-9-010: 001 (Pvt) (18-15-3-47 & -45 (Typ Rd Sec))
3-9-101: 092 (Pvt) through 095 (Pvt) (18-15-3-46) 3-9-012: 001
(City); 3-9-005:001 (Pvt) (18-15-3-46 & -47; File Plan 1341) B
C C C C Cbuilt plan documentation)
City Street Name
Slope I.D. No.
Neighborhood Area of Oahu
Slope Location Reference by Tax Map Key
Mokuhano Street Honokahua Street Oilipuu Place Hawaii Kai Drive
Hawaii Kai Drive Hawaii Kai Drive B C Slope toe or beyond Slope toe
or beyond Slope toe or beyond Slope toe or beyond Slope toe or
beyond NA NA Slope toe or beyond Slope toe or beyond Slope toe or
beyond Slope toe or beyond Slope toe or beyond Slope toe or beyond
Slope toe or beyond Slope toe or beyond Slope toe or beyond Slope
toe or beyond Slope toe or beyond Slope toe or beyond Slope toe or
beyond Slope toe or beyond Slope toe or beyond Slope toe or beyond
Slope toe or beyond Slope toe or beyond Slope toe or beyond Slope
toe or beyond Slope toe or beyond Slope toe or beyond Slope toe or
beyond Slope toe or beyond Slope toe or beyond Slope toe or beyond
Slope toe or beyond Slope toe or beyond Slope toe or beyond Slope
toe or beyond 0' 2' 1' 1' 1' 1' 1' 1' 1' 1' 1' 1' 1' 1' 1' 1' 1' 1'
1' 1' 1' 1' 1' 1' 1' 1' 2' 2' 0' 0' B B B B C C B B C A B B C A A B
B A A C C C C C C C B B C C C C C C B A A 2' 2' 2' 2' 2' 2' 2'
001 002 003 004-A 004-B 004-C
Kalama Valley Kalama Valley Kalama Valley Hawaii Kai Hawaii Kai
Hawaii Kai
Ownership of Approx. Abutting Horizontal Distance from Property
Line P/L to Slope Toe 2' Private 2'+ Private 1'+ Private Private
2'+ 2'+ Private Varies (No useable asCity/Private
Hawaii Kai Drive Kamehame Drive
004-D 005-A
Hawaii Kai Kamehame Ridge
Slope toe or beyond Slope toe or beyond Slope toe or beyond
Slope toe or beyond Slope toe or beyond Middle of slope to Slope
toe or beyond Slope toe or beyond Slope toe or beyond
Kamehame Drive Hoahana Place Waihili Place Hanohano Place
Hoolako Place Koko Head Park Road Hanauma Bay Road Polihale Place
Lumahai Place Kaluanui Road Kaluanui Road Kaluanui Road Kaluanui
Road Kaluanui Road Kaluanui Road Kaluanui Road Kaluanui Road
Kalihiwai Place Kamookoa Place Kamookoa Place Kamookoa Place
Kaloaloa Street Kawaiki Place Kauku Place Kapoho Place Kapapala
Place Kamoi Place Kaahue Street Kakiwa Place Kaipuhaa Place Kahuwai
Place Kahauloa Place Kaluanui Place Hokulani Street Uwao Street
Anolani Street Anolani Street
005-B 006 007 008 009 010 011 012 013 014-A 014-B 014-C 014-D
014-E 014-F 014-G 014-H 015 016-A 016-B 016-C 017 018 019 020 021
022 023 024 025 026 027 028 029 030 031A 031B
Kamehame Ridge Kamehame Ridge Kamehame Ridge Kamehame Ridge
Kamehame Ridge Hawaii Kai Hawaii Kai Portlock Portlock Mariners
Ridge Mariners Ridge Mariners Ridge Mariners Ridge Mariners Ridge
Mariners Ridge Mariners Ridge Mariners Ridge Mariners Ridge
Mariners Ridge Mariners Ridge Mariners Ridge Mariners Ridge
Mariners Ridge Mariners Ridge Mariners Ridge Mariners Ridge
Mariners Ridge Mariners Ridge Mariners Ridge Mariners Ridge
Mariners Ridge Mariners Ridge Mariners Ridge Hahaione Valley
Hahaione Valley Niu Valley Niu Valley
City/ Private 3-9-063: 001 (City) & 3-9-101: 098 (Pvt)
(18-6-2-20 & -21 (Typ Rd Sec)) Private 3-9-106: 001 (Pvt), 002
(Pvt), 003 (Pvt), 004 (Pvt), 005 (Pvt), 006 (Pvt), 007 (Pvt)
(90-33P Sht 8, 2 (Typ Rdwy Sec), 3 (Gen Layout)) Private 3-9-107:
076 (Pvt), 077 (Pvt), 078 (Pvt), 080 (Pvt) (90-79P Shts 10, 2 (Typ
Rdwy Sec), 3 (Gen Layout)) Private 3-9-107: 060 (Pvt) (90-79P Sht
12) Private 3-9-106: 107 (Pvt) (90-79P Sht 11) Private 3-9-106: 066
(Pvt) ,067 (Pvt), 068 (Pvt), 069 (Pvt) (90-33P Sht 10) Private
3-9-106: 082 (Pvt), 081 (Pvt) ,080 (Pvt), 059 (Pvt), 058 (Pvt)
(90-33P Sht 12) City 3-9-012: 010, 001 (Back road access to Koko
Head Regional Park) (Prelim Topo) City Park - Main Access Road
(Prelim Topo) Private 3-9-023: 074 (Pvt), 075 (Pvt) (H-09289 Sht 5;
13-6-1-15 (Typ Rdwy Sec)) Private 3-9-069: 013 (Pvt), 014 (Pvt)
(E-02733 Sht 5; 17-13-1-5 (Typ Rdwy Sec)) Private 3-9-008: 013
(Pvt) (663W Shts 4, 5, 2 (Typ Rdwy Sec), 3 (Gen Layout)) Private
3-9-008: 013 (Pvt) (663W Sht 6) Private 3-9-073: 014 (Pvt), 015
(Pvt), 016 (Pvt), 017 (Pvt) and 3-9-008: 041 (Pvt) (663W Sht 6)
Private 3-9-073: 033 (Pvt), 034 (Pvt) (B-04109 Shts 5, 2 (Typ Rdwy
Sec), 3 (Gen Layout)) Private 3-9-075: 056, 057,058 (Pvt) (C-05401
Shts 9, 2 (Typ Rdwy Sec), 3 (Gen Layout)) Private 3-9-076: 093
(Pvt) (C-05401 Sht 10) Private 3-9-076: 113 (Pvt), 091(Pvt), 093
(Pvt) (C-05401 Sht 10, 11) Private 3-9-076: 088 (Pvt) (C-05401 Sht
11) Private 3-9-088: 031 (Pvt), 032 (Pvt), 033 (Pvt), 034 (Pvt)
(78-006P Shts 10, 2 (Typ Rdwy Sec), 3 (Gen Layout)) Private
3-9-088: 052 (Pvt),053 (Pvt), 054 (Pvt), 055 (Pvt), 056 (Pvt)
(78-006P Sht 8) Private 3-9-076: 053 (Pvt) (78-006P Sht 8) Private
3-9-076: 052 (Pvt) (78-006P Sht 8) Private 3-9-074: 086 (Pvt), 087
(Pvt), 088 (Pvt),089 (Pvt), 090 (Pvt) (B-04109 Sht 16) Private
3-9-074: 061 (Pvt), 062 (Pvt), 063 (Pvt) (B-04109 Sht 15) Private
3-9-074: 056 (Pvt), 057 (Pvt), 058 (Pvt),059 (Pvt), 060 (Pvt)
(B-04109 Sht 14) Private 3-9-074: 053 (Pvt), 054 (Pvt) (B-04109 Sht
14) Private 3-9-074: 031 (Pvt), 032 (Pvt), 033 (Pvt) ,034 (Pvt)
(B-04109 Sht 13) Private 3-9-073: 040 (Pvt), 041 (Pvt) (B-04109 Sht
12) Private 3-9-073: 028 (Pvt), 029 (Pvt), 030 (Pvt), 031 (Pvt)
(B-04109 Sht 7) Private 3-9-074: 036 (Pvt), 037 (Pvt), 038 (Pvt),
039 (Pvt) (B-04109 Sht 12) Private 3-9-074:067 (Pvt), 068 (Pvt)
(B-04109 Sht 11) Private 3-9-074: 022 (Pvt),023 (Pvt), 024 (Pvt),
025 (Pvt) (B-04109 Sht 10) Private 3-9-073:038 (Pvt), 039(Pvt), 034
(Pvt), 035 (Pvt), 036 (Pvt) (B-04109 Sht 10) Private 3-9-073: 009
(Pvt), 010 (Pvt), 011 (Pvt) (B-04109 Sht 9) Private 3-9-083: 016
(Pvt), 017 (Pvt) (C-05507 Sht 19; 19-5-1-22 (Typ Rdwy Sec)) Private
3-9-083: 049 (Pvt) (C-05507 Sht 15)) Private 3-7-015: 065 (Pvt)
(74-040P Sht 6; 17-8-3-2 (Typ Rd Sec)) Private 3-7-015: 065 (Pvt)
(74-040P Sht 7; 17-8-3-2 (Typ Rd Sec))
W.O. 4683-20
GEOLABS, INC.
NOVEMBER 2012
PLATE 4.1
Summary of Slope Ownership Assessment Phase III - Rock Slide
Potential Inspections Rockfall Hazard Rating System Database Update
No. 1 Project No. 01154 Island of Oahu, HawaiiUpdated Preliminary
Rating Property Line Location (P/L) Slope toe or beyond Slope toe
or beyond Slope toe or beyond Slope toe or beyond Slope toe or
beyond Slope toe or beyond Slope toe or beyond Slope toe or beyond
Slope toe or beyond Slope toe or beyond Slope toe or beyond Slope
toe or beyond Slope toe or beyond Slope toe or beyond Slope toe or
beyond Slope toe or beyond Slope toe or beyond Slope toe or beyond
Slope toe or beyond Slope toe or beyond Slope toe or beyond Slope
toe or beyond Slope toe or beyond Slope toe or beyond Slope toe or
beyond Slope toe or beyond Slope toe or beyond Middle of slope 0'
to 20' 36' to 46' 2' to 15' 0' to 2.5' 1' to 2.5' 0' to 2' 0' 2' to
5' City Private Private Private Private Private State Private 0' 0'
0' 0' 0' 0' 0' 0' 0' 0' 0' 0' 0' 0' 0' 0' 0' 12' to 15' Private
Private City Private Private Private Private City Private Private
Private Private Private Private Private Private Private Private 0'
10' 0' 0' Private Private Private City/Private C B C C C A A C C A
C C C B C C C C C C C B B A B B B A C B B B A B B A B C Slope
Location Reference by Tax Map Key
City Street Name
Slope I.D. No.
Neighborhood Area of Oahu
Hoana Place Kainoa Place Mona Street Ahuwale Street Poola Street
Poola Street
032 033 034 035 036-A 036-B
Wailupe Valley Wailupe Valley Wailupe Valley Wailupe Valley
Waialae Iki Waialae Iki
Ownership of Approx. Abutting Horizontal Distance from Property
Line P/L to Slope Toe 0' Private 0' Private 0' City 0' Private 0'
Private 0' Private
Poola Street Poola Street Poola Street Laukahi Street
036-C 036-D 036-E 037-A
Waialae Iki Waialae Iki Waialae Iki Waialae Iki
Laukahi Street Laukahi Street Kamole Street Kamole Street Ehupua
Place Ohialoke Street Hoaaina Place Ihiloa Loop Ihiloa Loop Ihiloa
Loop Kihi Street Luinakoa Street Halekoa Drive Halekoa Drive
Halekoa Drive Wahinekoa Place Malu Place Koko Drive Koko Drive Koko
Drive
037-B 037-C 038-A 038-B 039 040 041 042-A 042-B 042-C 043 044
045-A 045-B 045-C 046 047 048-A 048-B 048-C
Waialae Iki Waialae Iki Waialae Iki Waialae Iki Waialae Iki
Waialae Iki Waialae Iki Waialae Iki Waialae Iki Waialae Iki Waialae
Iki Waialae Nui Waialae Nui Waialae Nui Waialae Nui Waialae Nui
Waialae Nui Wilhemina Rise Wilhemina Rise Wilhemina Rise
3-6-004: 017 (Pvt) (04-023 Sht 13) 3-6-019: 042 (Pvt) (10-7-2-31
& -42 (Typ Rd Sec)) 3-6-004: 001 (City) (272 W-P Sht 6;
14-10-1-58b (Typ Rd Sec)) 3-6-022: 026 (Pvt) (13-5-3-20 & -31
(Typ Rd Sec)) 3-5-073: 035 (Pvt) , 036 (Pvt) (K-02782 Sht 6, 2 (Gen
Plan)) 3-6-023: 056 (Pvt), 057 (Pvt), 058 (Pvt), 059 (Pvt), 060
(Pvt) and 3-6-025: 001 (Pvt) (K-02782 Shts 3 (w/ Typ Rdwy Sec), 4)
3-5-024: 006 (Pvt) (K-02782 Sht 3) 3-6-023: 078 (Pvt), 079 (Pvt)
(K-02782 Sht 3 and 16-3-2-9 (Typ Channel Sec)) 3-5-053: 078 (Pvt)
(K-02782 Sht 3) 3-5-051: 025 (Pvt), 024 (Pvt), 023 (Pvt), 022
(Pvt), 082 (Pvt), 019 (Pvt) and 3-5-047: 001 (City) (241W-P Shts 5,
2 (Gen Layout) and 13-2-3-30 (Typ St Sec)) 3-5-054: 053 (Pvt)
(241W-P Sht 7) 3-5-054: 002 (Pvt), 003 (Pvt) (241W-P Sht 6)
3-5-054:025 (City) (241W-P Shts 9, 11) 3-5-051: 001 (Pvt) (241W-P
Sht 6) 3-5-067: 003 (Pvt), 007 (Pvt) (241W-P Sht 1) 3-5-067: 002
(Pvt) (558W-C Shts 11, 1 (Gen Layout) and 16-12-1-33 (Typ St Sec))
3-5-066: 041 (Pvt), 042 (Pvt), 044 (Pvt) (558W-C Shts 9, 10)
3-5-065: 005 (City) (558W-C Sht 6) 3-5-067: 015 (Pvt) (558W-C Shts
7, 8) 3-5-066: 022 (Pvt) (558W-C Sht 8) 3-5-068: 028 (Pvt) (558W-C
Sht 12) 3-5-024: 001 (Pvt) (131W-P Shts 12, 2 (Gen Layout) and
10-4-3-88 (Typ Rd Sec)) 3-5-039: 082 (Pvt) (131W-P Sht 14) 3-5-039:
079 (Pvt), 077 (Pvt) (131W-P Sht 14) 3-5-039: 073 (Pvt), 072 (Pvt),
069 (Pvt), 068 (Pvt) (131W-P Sht 13) 3-5-038: 068 (Pvt) and
3-5-039: 025 (Pvt) (131W-P Shts 3 (Typ Rd Sec), 4) 3-5-024: 001
(Pvt) (E-07252 Shts 5, 6 (Typ Rdwy Sec)) 3-3-019: 004 (Pvt), 057
(Pvt) (Preliminary Topo Map) 3-3-019: 057,056,023,052,053 3-3-019:
005 (City) (Preliminary Topo Map) 3-3-018: 075 (Pvt), 083 (Pvt)
(Preliminary Topo Map) 3-3-023: 002 (Pvt), 003 (Pvt) and 3-3-024:
082 (Pvt) (Preliminary Topo Map) 3-3-006: 031 (Pvt), 033 (Pvt), 034
(Pvt), 035 (Pvt), 036 (Pvt), 037 (Pvt) (01-22 Shts 8, 9) 3-3-007:
016 (Pvt) (01-022 Sht 15) 3-3-007: 002 (Pvt), 003 (Pvt) (01-022 Sht
17) 3-1-042: 017 (State) (10-10-2-34, -37 (Typ Rd Sec)) 3-1-035:
008 (