HomeMy WebLinkAboutLUA-17-000069_REPORT 01DEPARTMENT OF COMMUr
AND ECONOMIC DEVELOPMENT
DATE:
PROJECT NUMBER:
PROJECT NAME:
PROJECT MANAGER:
OWNER:
CONTACT:
LOCATION:
DESCRIPTION:
PLANNING DIVISION
CERTIFICATE OF EXEMPTlu.ua------=:-:-~-i CONCURRENCE
FROM CRITICAL AREAS REGULATI NS DATE a,.J1uf1J
EVALUATION FORM & DECISION
February 16, 2017
LUA17-000069
NAME
I l ii I
\S<r:P Iµ,::
Je:n n'a
Hazard Tree and Vegetation Management at Pinnacle Apts.
Jill Ding, Senior Planner
Pinnacle Apartments
1400 Lake Wash ignton Blvd N
Renton, WA 98056
Thomas Kach man, Essex Property Trust
11911 NE 1st St
B112
Bellevue, WA 98005
1400 LAKE WASHINGTON BLVD N
The applicant is requesting a Critical Areas Exemption for the removal and /or
structural pruning of hazardous trees located on Protected Slopes and Landslide
Hazard Areas. There are 10 trees that have been identified as potentially
hazardous trees. The applicant submitted a Geotechnical Evaluation of Hazard
Tree Management Plan, prepared by Zipper Geo Associates, LLC dated
November 22, 2016; a hazard tree evaluation prepared by arborists NW, LLC;
and a hazard tree evaluation prepared by A&M Tree Service NW, Inc. dated
March 27, 2015.
The applicant previously submitted a Critical Areas Exemption under
LUAlS-000079, the original application included the arborists NW, LLC hazard
tree evaluation. The original Critical Areas Exemption was denied as the City
determined that the applicant had failed to provide sufficient evidence proving
that the 10 trees requested for removal were a danger to persons or property if
they were to fail, which is a requirement that needs to be met in order for the
trees to be considered dangerous. The applicant has subsequently provided
additional information, including the hazard tree evaluation prepared by A&M
Tree Service NW, and most recently the Geotechnical Evaluation prepared by
Zipper Geo Associates, LLC. In addition photos were emailed to the City on
February 8, 2016 showing two trees that had slid down the slope (although it
was unclear as to whether the trees that failed were part of the original request
for tree removal).
The hazard tree evaluation prepared by arborists NW, LLC identified 10 trees fo1
Page 1 of 4
DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT ------... Renton®
DATE:
PROJECT NUMBER:
PROJECT NAME:
PROJECT MANAGER:
OWNER:
CONTACT:
LOCATION:
DESCRIPTION:
PLANNING DIVISION
CERTIFICATE OF EXEMPTION
FROM CRITICAL AREAS REGULATIONS
EVALUATION FORM & DECISION
February 16, 2017
LUA17-000069
Hazard Tree and Vegetation Management at Pinnacle Apts.
Jill Ding, Senior Planner
Pinnacle Apartments
1400 Lake Washignton Blvd N
Renton, WA 98056
Thomas Kach man, Essex Property Trust
11911 NE 1st St
B112
Bellevue, WA 98005
1400 LAKE WASHINGTON BLVD N
The applicant is requesting a Critical Areas Exemption for the removal and/or
structural pruning of hazardous trees located on Protected Slopes and Landslide
Hazard Areas. There are 10 trees that have been identified as potentially
hazardous trees. The applicant submitted a Geotechnical Evaluation of Hazard
Tree Management Plan, prepared by Zipper Geo Associates, LLC dated
November 22, 2016; a hazard tree evaluation prepared by arborists NW, LLC;
and a hazard tree evaluation prepared by A&M Tree Service NW, Inc. dated
March 27, 2015.
The applicant previously submitted a Critical Areas Exemption under
LUA15-000079, the original application included the arborists NW, LLC hazard
tree evaluation. The original Critical Areas Exemption was denied as the City
determined that the applicant had failed to provide sufficient evidence proving
that the 10 trees requested for removal were a danger to persons or property if
they were to fail, which is a requirement that needs to be met in order for the
trees to be considered dangerous. The applicant has subsequently provided
additional information, including the hazard tree evaluation prepared by A&M
Tree Service NW, and most recently the Geotechnical Evaluation prepared by
Zipper Geo Associates, LLC. In addition photos were emailed to the City on
February 8, 2016 showing two trees that had slid down the slope {although it
was unclear as to whether the trees that failed were part of the original request
for tree removal).
The hazard tree evaluation prepared by arborists NW, LLC identified 10 trees for
Page 1 of 4
City of Renton Department of Community & Econ an efopment ~ertificate of Exemption from Critical Areas Regulations
LUAll-000069 Hazard Tree and Vegetation Management at Pinnacle Apts.
CRITICAL AREA:
EXEMPTION JUSTIFICATION:
removal and/or structural pruning (identified in the report as 1-10). The report
notes that many of the trees may be cut for re-sprouting to retain the structural
stability of the slopes and that the planting of additional trees and shrubs
would mitigate for the removal of the trees on site.
The hazard tree evaluation prepared by A&M Tree Service NW, included slightly
different recommendations for the management of the trees on site. The A&M
report noted 9 trees for removal/structural pruning (identified in the report as
191-199) as they did not concur that tree 10 identified by arborists NW, LLC
constituted a hazardous tree. The report recommended that trees 196 and 197
would be appropriate for structural pruning and that trees 191-195, 198 and 199
be removed. The A&M report also recommended that a geotechnical engineer
be consulted with regards to slope stability.
The Geotechnical Evaluation prepared by Zipper Geo Associates, LLC included a
summary of the previously submitted hazard tree evaluations by arborists NW,
LLC and A&M Tree Service NW as well as a discussion of the appropriate
measures, from a geological standpoint, that should be considered for
management of trees and stability of the steep slopes on site. The geotechnical
report noted that trees 1-4 (191-194 per A&M) had been undermined by
landslide head scarp and that the weight and wind loading of these trees could
trigger a landslide which could potentially impact a carport area associated
with the Pinnacle Apartments as well as upslope regression of the landslide
feature. The report recommends that these trees be cut back and allowed to
resprout to retain the soil reinforcement of the live root system while reducing
the weight of the trees resulting in a net increase in slope stability. The report
notes that cut wood should not be left on the slope as this could reduce the
stability of the slope. The report recommends that trees 5 & 6 (195 & 196 per
A&M) should be managed by cutting and allowing the trees to resprout or
through structural pruning. Tree 7 (197 per A&M) is a Douglas fir tree located at
the top of a 20-30 degree slope, which appears to be leaning towards Building
E. Per the geotechnical report there does not appear to be any history of slope
instability in the area. This tree could be managed through structural pruning or
removal. If the tree is removed, the live root system should be left in place and
an additional tree should be planted nearby as Douglas fir trees cannot be
relied upon to resprout. Trees 8 & 9 (198 & 199 per A&M) are a Douglas fir and
cottonwood tree with interdependent root systems located above the carport
and parking lot area for Building H. Their root systems have been partially
undermined by the adjacent bluff. The geotechnical report recommends that
both trees be cut back, the cottonwood tree is expected to resp rout, however an
additional tree would need to be planted to mitigate for the loss of the Douglas
fir tree. The geotechnical report recommended that tree 10 (not listed as a
hazardous tree per A&M) be structurally pruned only if the work can be
accomplished without causing significant disturbance of the ground surface.
Protected slopes, sensitive slopes, Landslide Hazard Areas, and Erosion Hazard Areas.
Dangerous tree removal.
Page 2 of 4
City of Renton Department of Community & Econor. e/opment :ertificate of Exemption from Critical Areas Regulations
LUA17-000069 Hozard Tree and Vegetation Management at Pinnacle Apts.
FINDINGS:
DECISION:
CONDITIONS:
The proposed development is consistent with the following findings pursuant to
RMC section 4-3-0SOC.2.d:
i. The activity is not prohibited by this or any other provision of the Renton
Municipal Code or State or Federal law or regulation;
ii. The activity will be conducted using best management practices as specified
by industry standards or applicable Federal agencies or scientific principles;
iii. Impacts are minimized and, where applicable, disturbed areas are
immediately restored;
iv. Where water body or buffer disturbance has occurred in accordance with an
exemption during construction or other activities1 revegetation with native
vegetation shall be required;
v. If a hazardous material, activity, and/or facility that is exempt pursuant to
this Section has a significant or substantial potential to degrade groundwater
quality, then the Administrator may require compliance with the Wellhead
Protection Area requirements of this Section otherwise relevant to that
hazardous material, activity, and/or facility. Such determinations will be based
upon site and/or chemical-specific data.
An exemption from the Critical Areas Regulations is hereby Approved with
Conditions*.
1. This approval is granted for the removal of Trees 1-4 and Trees 8 and 9.
Trees 5-7 may be managed through structural pruning as recommended in the
submitted Geotechnical Evaluation prepared by Zipper Geo Associates, LLC.
2. All work shall occur in accordance with the recommendations provided in the
Geotechnical Evaluations prepared by Zipper Geo Associates, LLC.
3. Cut wood shall be prevented from cascading down steep slope areas as this
could contribute to additional erosion and slope stability.
4. Replacement trees are required for the removal of any evergreen trees.
Replacement trees shall be planted in accordance to the recommendations
provided in the Geotechnical Evaluation provided by Zipper Geo Associates,
LLC.
Page 3 of 4
City of Renton Deportment of Community & Econom ·lopment
Hawrd Tree and Vegetation Management at Pinnacle Apts.
":ertificote of Exemption from Critical Areas Regulations
LUAll-000069
CONDITIONS:
SIGNATURE & DATE OF DECISION:
Jennifer Henning, Planning Director
5. An arborist shall inspect any cut trees to verify that re-sprouting has occurred
as intended and/or that any pruned trees are recovering from the pruning
process. Any trees that have not re-sprouted or are not recovering from pruning
shall be replaced with two replacement trees. The species of replacement trees
shall be determined by the project arborist based on the site conditions at the
planting location.
February 16, 2017
Date
The above land use decision will become final if the decision is not appealed within the 14-day appeal
period (RCW 43.21.C.075(3); WAC 197-11-680).
APPEALS: An appeal of this administrative land use decision must be filed in writing together with the
required fee to the City of Renton Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA
98057, on or before 5:00 p.m., on March 02, 2017. RMC 4-8-110 governs appeals to the Hearing Examiner
and additional information regarding the appeal process may be obtained from the Renton City Clerk's Office,
(425) 430-6510.
RECONSIDERATION: Within 14 days of the decision date, any party may request that the decision be
reopened by the approval body. The approval body may modify his decision if material evidence not readily
discoverable prior to the original decision is found or if he finds there was misrepresentation of fact. After
review of the reconsideration request1 if the approval body finds sufficient evidence to amend the original
decision, there will be no further extension of the appeal period. Any person wishing to take further action
must file a formal appeal within the 14-day appeal time frame.
EXPIRATION: Five (5) years from the date of decision (date signed).
Attachments: Vicinity/Neighborhood Detail Map
Page 4 of 4
DEPARTMENT OF COM Ml 'Y
AND ECONOMIC DEVELOPMENT
Planning Division
LAND USE PERMIT MASTER APPLICATION
PROPERTY OWNER(S) PROJECT INFORMATION
NAME: BRE-FMCA LLC / Essex PROJECT OR DEVELOPMENT NAME:
Hazard Tree and Vegetation Management
ADDRESS: 1400 Lake Washington Blvd N
CITY: ZIP: Renton, 98056 WA
PROJECT/ADDRESS(S)/LOCATION AND ZIP CODE:
1400 Lake Washington Blvd N RECEIVED Renton, WA 98056
FEB I 3 2017
425-457-1592
TELEPHONE NUMBER: KING COUNTY ASSESSOR'S ~~~~~T~fl'
334450-0390 P:t, .. (';;'.;C cl c:~:C)N
APPLICANT (if other than owner)
Thomas Kachman
NAME: EXISTING LAND USE(S):
Multiple Residence
Essex property Trust
COMPANY (if applicable):
PROPOSED LAND USE(S):
Multiple Residence
11911 NE 1" street #8302
ADDRESS:
EXISTING COMPREHENSIVE PLAN MAP DESIGNATION:
Bellevue 98005 PROPOSED COMPREHENSIVE PLAN MAP
CITY: ZIP: DESIGNATION (if applicable)
N/A
425-457-1592
TELEPHONE NUMBER: EXISTING ZONING:
CONTACT PERSON PROPOSED ZONING (if applicable):
N/A
NAME:
Thomas SITE AREA (in square feet):
Kachman
COMPANY
Essex Property trust:
SQUARE FOOTAGE OF PUBLIC ROADWAYS TO BE
DEDICATED:
N/A
11911NE 1-Street #8302
ADDRESS:
SQUARE FOOTAGE OF PRIVATE ACCESS EASEMENTS:
N/A
CITY: 98005 PROPOSED RESIDENTIAL DENSITY IN UNITS PER NET
Bellevue ZIP:
WA
ACRE (if applicable)
NIA
TELEPHONE NUMBER AND EMAIL ADDRESS: NUMBER OF PROPOSED LOTS (if applicable)
425-457-1572 N/A
tkachman@essex.com NUMBER OF NEW DWELLING UNITS (if applicable):
N/A
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P"OJECT INFORMATION (con •... ued) ~-----'------~'------------~
NUMBER OF EXISTING DWELLING UNITS (if applicable): PROJECT VALUE: N/A
N/A
SQUARE FOOTAGE OF PROPOSED RESIDENTIAL
BUILDINGS (if applicable): N/A
IS THE SITE LOCATED IN ANY TYPE OF
ENVIRONMENTALLY CRITICAL AREA, PLEASE INCLUDE
SQUARE FOOTAGE (if applicable}:
SQUARE FOOTAGE OF EXISTING RESIDENTIAL
BUILDINGS TO REMAIN (if applicable): N/A
SQUARE FOOTAGE OF PROPOSED NON-RESIDENTIAL
D AQUIFIER PROTECTION AREA ONE
CJ AQUIFIER PROTECTION AREA TWO
BUILDINGS (if applicable): N/A
SQUARE FOOTAGE OF EXISTING NON-RESIDENTIAL
BUILDINGS TO REMAIN (if applicable}: N/A
NET FLOOR AREA ON NON-RESIDENTIAL BUILDINGS (if
applicable): N/A
NUMBER OF EMPLOYEES TO BE EMPLOYED BY THE NEW
PROJECT (if applicable): N/A
CJ FLOOD HAZARD AREA
Mi GEOLOGIC HAZARD
CJ HABITAT CONSERVATION
CJ SHORELINE STREAMS & LAKES
CJ WETLANDS
LEGAL DESCRIPTION OF PROPERTY
___ sq.ft.
___ sq.ft.
___ sq.ft.
___ sq.ft.
___ sq.ft.
(Attach leaal descriotion on senarate sheet with the followina information Included)
SITUATE IN THE SW QUARTER OF SECTION _5_, TOWNSHIP ...lL, RANGE _5_, IN THE
CITY OF RENTON, KING COUNTY, WASHINGTON
AFFIDAVIT OF OWNERSHIP
I, (Print Name/s} Thomas Kachman declare under penalty of perjury under the laws of the State of Washington that I am (please
check one) __ the current owner of the property involved in this application or _xx_ the authorized representative to act for a
corporation (please attach proof of authorization) and that the foregoing statements and answers herein contained and the information
herewith are in all respects true and correct to the best of my knowiedge and belief.
~ of Owner/Representative
STATE OF WASHINGTON )
) ss
02/13/2017 ---=---e..te
COUNTY OF KING )
I certify that I know or have satisfactory evidence that / ho 1/la.S l<tw/,-
signed this instrument and acknowledge n to be his/her/their free and voluntary act for the
uses and purpose mentioned in the instrument.
1Vhr' Tluu'
Dated / / Notary Public in and for the State of Washington
Notary (Print}: t.J ..If J: I ft A 1.
My appointment expires: __ ..,,O:..,G4-l..,1e..q4-/ .... 1 .. o...,lut'~--------r1
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DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
SUBMITTAL REQUIREMENTS
CRITICAL AREAS EXEMPTION
Planning Division
1055 South Grady Way-Renton, WA 98057
Phone: 425-430-7200 Fax: 425-430-7231
www.rentonwa.gov
PURPOSE: To allow certain activities to intrude into a critical area or required buffer subject to the City
providing a letter of exemption of any listed conditions or requirements.
FREE CONSULTATION MEETING: Prior to submitting an application, the applicant should informally
discuss the proposed development with the Planning Division. The Planning Division will provide
assistance and detailed information on the City's requirements and standards. Applicants may also take
this opportunity to request the waiver of the City's typical application submittal requirements, which
may not be applicable to the specific proposal. For further information on this meeting, see the
instruction sheet entitled "Submittal Requirements: Pre-Application."
COMPLETE APPLICATION REQUIRED: In order to accept your application, each of the numbered items
must be submitted at the same time. If you have received a prior written waiver of a submittal item(s)
during a pre-application meeting, please provide the waiver form in lieu of any submittal item not
provided. All plans and attachments must be folded to a size not exceeding 8% by 11 inches.
APPLICATION SCREENING: Applicants are encouraged to bring in one copy of the
application package for informal review by staff, prior to making the requested number
of copies, colored drawings, or photo reductions. Please allow approximately 45
minutes tor application screening.
APPLICATION SUBMITTAL HOURS: Applications should be submitted to Planning Division staff at the
6th floor counter of Renton City Hall, 1055 South Grady Way, between 8:00 a.m. and 4:00 p.m. Monday
through Friday. Please call your assigned project manager to schedule an appointment or call (42S) 430-
7200 to reach the Planning Division. Due to the screening time required, applications delivered by
messenger cannot be accepted.
ADDITIONAL PERMITS: Additional permits from other agencies may be required. It is the applicant's
responsibility to obtain these other approvals. Information regarding these other requirements may be
found at http://apps.ecy.wa.gov/opas/
FEB 1 3 2017
All Plans and Attachments must be folded to 8 X"by 11"
APPLICATION MATERIALS:
1. D Pre-Application Meeting Summary: If the application was reviewed at a "pre-application
meeting", please provide 5 copies of the written summary provided to you.
2. D Waiver Form: If you received a waiver form during or after a "pre-application meeting",
please provide S copies of this form.
3. D Land Use Permit Master Application Form: Please provide the original plus 11 copies of the
COMPLETED City of Renton Planning Division's Master Application form. Application must
have notarized signatures of ALL current property owners listed on the Title Report. If the
property owner is a corporation, the authorized representative must attach proof of signing
authority on behalf of the corporation. The legal description of the property must be
attached to the application form.
4. D Critical Areas Exemption Form (attached): Please provide 3 copies of the attached Critical
Areas Exemption form if the project consists of one of the listed activities eligible for SEPA
exemption.
5. D Site Plan: Please provide 12 copies of a fully-dimensioned plan sheet drawn at a scale of
1"=20' (or other scale approved by the Planning Division). We prefer the site plan be drawn on
one sheet of paper unless the size of the site requires several plan sheets to be used. If you
are using more than a single plan sheet, please indicate connecting points on each sheet.
The Site Plan should show the following:
Name of proposed project
Date, scale, and north arrow (oriented to the top of the paper/plan sheet)
Drawing of the subject property with all property lines dimensioned and names of
adjacent streets
Widths of all adjacent streets and alleys
Location of all existing public improvements including, but not limited to, curbs,
gutters, sidewalks, median islands, street trees, fire hydrants, utility poles, etc.,
along the full property frontage
Location and dimensions of existing and proposed:
1. structures
2. setbacks
3. parking, off-street loading space, curb cuts and aisle ways FEB I 3 2 U 17 4. fencing and retaining walls
5. free-standing signs and lighting fixtures C!TY Cl'' fi: :), ,CN
6. refuse and recycling areas Pi.A7':L\C .-.,,..,,: .Y,
7. utility junction boxes and public utility transformers
8. storage areas and job shacks/sales trailers/model homes
Location and dimensions of all easements referenced in the title report with the
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recording number and type of easement (e.g. access, sewer, etc.) indicated
Location and dimensions of natural features such as streams, lakes, required buffer
areas, open spaces, and wetlands
Ordinary high water mark and distance to closest area of work for any project
located within 200-feet from a lake or stream
A legend/analysis of the following information MUST be included on the site plan:
Total square footage of the site
Square footage (by floor and overall total) for each individual building and/or use
Total square footage of all buildings/structure footprints
Total impervious surfacing. List the square footage of both existing impervious
area to remain plus new impervious areas to be installed, and the total square
footage of parking areas
Percentage of lot coverage
Square footage of all landscaping (total, interior of parking lot, and wildlife
habitat/natural areas)
Allowable and proposed building heights
All building setbacks required by code
Proposed building setbacks
Square footage of any on-site critical areas
Parking analysis including the following:
1. Number of stalls required by Code (if more than one use/ratio show required
number for each use
2. Total number of stalls proposed (if less or more than total required attach a
request for a parking modification to the application package
3. Location and number of "ADA accessible" stalls, compact, employee
and/or guest parking stalls, and parking space dimensions
4. Sizes of various types of stalls proposed
5. Angle of stalls (if other than 90 degrees)
6. Location and size of curb cuts
7. Traffic flow within the parking, loading, maneuvering areas, ingress and egress
8. Location of wheel stops
9. Loading space(s) location and dimensions
10. Number of stacking space(s) for any drive-up windows
11. Location and dimensions of any bicycle racks, bus shelters, carpool parking
spaces, or facilities designed to accommodate access to the site.
6. D Neighborhood Detail Map: Please provide 12 copies of a map drawn at a scale of 1" = 100' or
1" = 200' (or other scale approved by the Planning Division) to be used to identify the site
location on public notices and to review compatibility with surrounding land uses. The map
shall identify the subject site with a much darker perimeter line than surrounding properties
and include at least two cross streets in all directions showing the location of the subject site
relative to property boundaries of surrounding parcels. The map shall also show: the
property's lot lines, lot lines of surrounding properties, boundaries of the City of Renton (if
applicable), north arrow (oriented to the top of the plan sheet), graphic scale used for the
map, and City of Renton (not King County) street names for all streets shown. Please ensure
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all information fits on a single map sheet.
Kroll Map Company (206-448-6277) produces maps that may serve this purpose or you may
use the King County Assessor's maps as a base for the Neighborhood Detail Map. Additional
information (i.e. current city street names) will need to be added by the applicant.
7. D Wetland Assessment: Please provide 12 copies of the map and 5 copies of the report if ANY
wetlands are located on the subject property or within 100 feet of the subject property. The
wetland report/delineation must include the information specified in RMC 4-8-120D. In
addition, if any alteration to the wetland or buffer is proposed, 5 copies of a wetland
mitigation plan is also required. See RMC 4-8-120D for plan content requirements.
8. D Standard Stream or Lake Study: Please provide 12 copies of a report containing the
information specified in RMC Section 4-8-120D. In addition, if the project involves an
unclassified stream, a supplemental stream or lake study is also required (12 copies). If any
alteration to a water-body or buffer is proposed a supplemental stream or lake study (12
copies) and a mitigation plan (12 copies) are also required. See RMC 4-8-120D for plan
content requirements.
9. D Flood Hazard Data: Please provide 12 copies of a scaled plan showing the nature, location,
dimensions, and elevations of the area in question; existing or proposed structures, fill,
storage of materials, and drainage facilities. Also indicate the following:
Elevation in relation to mean sea level of the lowest floor (including basement) of all
structures
Elevation in relation to mean sea level to which any structure has been floodproofed
Certification by a registered professional engineer or architect the flood proofing
methods criteria in RMC HU4-3-0SOUH have been met
Description of the extent to which a watercourse will be altered or relocated as a
result of proposed development
10. D Habitat Data Report: If the project site contains or abuts a critical habitat per RMC 4-3-
0SOBSb, please provide 12 copies of a report containing the information specified in Section
4-8-120D of the Renton Municipal Code.
11. D Geotechnical Report: Please provide 5 copies of a study prepared and stamped by a State of
Washington licensed professional engineer including soils and slope stability analysis, boring
and test pit logs, and recommendations on slope setbacks, foundation design, retaining wall
design, material selection, and all other pertinent elements.
12. D Grading Plan, Detailed: Please provide 12 copies of a 22" x 34" plan drawn by a State of
Washington Licensed civil engineer or landscape architect at a scale of one inch to forty feet
clearly indicating the following:
Graphic scale and north arrow
Dimensions of all property lines, easements, and abutting streets
Location and dimension of all on-site structures and the location of any structures
within 15-feet of the subject property or that may be affected by the proposed work
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Accurate existing and proposed contour lines drawn at two-foot, or less, intervals
showing existing ground and details of terrain and area drainage to include
surrounding off-site contours within 100-feet of the site
Location of natural drainage systems, including perennial and intermittent streams and
the presence of bordering vegetation
Setback areas and any areas not to be disturbed
Finished contours drawn at two-foot intervals as a result of grading
Proposed drainage channels and related construction with associated underground
storm lines sized and connections shown
Finished floor elevation(s) of all structures, existing and proposed
General notes addressing the following (may be listed on a cover sheet):
Area in square feet of the entire property
Area of work in square feet
Both the number of tons and cubic yards of soil to be added, removed, or relocated
Type and location of fill origin, and destination of any soil to be removed from site
13. 0 Topography Map: Please provide 4 copies of a plan showing the site's existing contour lines at
five-foot vertical intervals.
14. D Drainage Control Plan: Please provide 4 copies of a plan drawn to scale and stamped by a
Washington State licensed professional engineer and complying with the requirements of
Renton Municipal Code, Section 4-6-030 and the King County Surface Water Management
Design Manual, 2009 edition, as adopted and amended by the City of Renton.
1S. 0 Drainage Report: Please provide 4 copies of a report complying with the requirements of the
City of Renton Drafting Standards, Section 4-6-030 of the City of Renton Municipal Code, the
King County Surface Water Design Manual (KCSWDM), 2009 edition, and the City of Renton
Amendments to the KCSWDM, Chapters 1 and 2 as adopted by the City of Renton. The report
(TIR) must be stamped and dated by a civil engineer and shall contain the following:
Table of Contents
Technical Information Report (TIR) Worksheet
Section 1: Project Overview
Section 2: Conditions and Requirements Summary
Section 3: Offsite Analysis
Section 4: Flow Control and Water Quality Facility Analysis and Design
Section 5: Conveyance System Analysis and Design
Section 6: Special Reports and Studies
Section 7: Other Permit
Section 8: CSWPPP Analysis and Design
Section 9: Bond Quantities, Facility Summaries, and Declaration of Covenant
Section 10: Operations and Maintenance Manual.
16. D Plan Reductions: Please provide one 8 Y." x 11" legible reduction of each full size plan sheet
(unless waived by your City of Renton Project Manager). The sheets that are always needed in
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reduced form are: landscape plans, conceptual utility plans, site plan or plat plan,
neighborhood detail map, topography map, tree cutting/land clearing plan, critical areas
plans, grading plan, and building elevations. These reductions are used to prepare public
notice posters and to provide the public with information about the project. The quality of
these reductions must be good enough so that a photocopy of the reduced plan sheet is also
legible. The reduced plans are typically sent in PDF format to the print shop and then are
printed on opaque white mylar-type paper (aka rhino cover) to ensure legibility. If your
reduced plans are not legible once photocopied, you will need to increase the font size or try a
different paper type. Illegible reductions cannot be accepted. Please also be sure the reduced
Neighborhood Detail Map is legible and will display enough cross streets to easily identify the
project location when cropped to fit in a 4" by 6" public notice space. Once the reductions
have been made, please also make one 8 :W' x 11" regular photocopy of each photographic
reduction sheet. Some of the local Renton print shops that should be able to provide you with
reductions of your plans are Alliance Printing (425) 793-5474, Apperson Print Resources
(425) 251-1850, and PIP Printing (425) 226-9656. Nearby print shops are Digital
Reprographics (425) 882-2600 in Bellevue, Lithe Design {206) 574-3000 and Reprographics
NW/Ford Graphics (206) 624-2040.
All Plans and Attachments must be folded to 8~11 by 11"
-6 -04/12
H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Critical Areas Exemption.doc
CRITICAL AREAS EXEMPTION
Applicant Name
Thomas Kachman
Parcel Number
334450-0390
Brief Description of Project
(FOR SEPA EXEMPT ACTIVITIES)
Planning Division
1055 South Grady Way-Renton, WA 98057
Phone: 425-430-7200 Fax: 425-430-7231
I Project Na me
Pinnacle Hazard Tree and Vegetation Management
Phone Number
425-457-1572
I Project Address
1400 Lake Washington Blvd N, Renton, WA 98056
The Pinnacles are a large apartment complex build above and below a steep, vegetative slope. Because of its
designation, vegetation in this area has not been managed. This has lead to numerous trees being classified as
hazard trees by a licensed arborist. The Pinnacles would like to remove the hazard trees and plant additional native
vegetation in the critical area to prevent future slides.
Type of Critical Area D Work Occurs in ~ Work Occurs in
Steep slopes Critical Area Buffer
PURPOSE: Exempt activities provided with a letter of exemption from the Development Services
Administrator may intrude into a critical area or required buffer (Subject to any conditions or
requirements provided by the Administrator).
APPLICABILITY OF EXEMPTIONS: The following is a general list of activities that may be exempt from the
critical areas regulations. More specific descriptions of the activities are contained in the Critical Areas
Regulations. Some of the listed activities may not be exempt in certain critical areas. The Planning
Division will evaluate you request according to the City of Renton Critical Areas Regulations in RMC 4-3-
0SOC, J, L, and N.
I AM REQUESTING A CRITICAL AREAS EXEMPTION FOR ONE OR MORE OF THE FOLLOWING ACTIVITIES:
D Conservation, Enhancement, and Related Activities:
Conservation or preservation of soil, water, vegetation, fish, and other wildlife
Enhancement activities as defined in chapter 4-11 RMC D;
Any critical area, buffer restoration, or other mitigation activities that have been approved
by the City
D Research and Site Investigation:
Nondestructive education and research
Site investigative work necessary for land use application submittals such as surveys, soil
logs, etc.
D Agricultural, Harvesting, and Vegetation Management:
Harvesting wild foods
. 7. 04/12
H :\CED\Data\Forms-T emplates\Setf-Help Handouts\Planning\Critical Areas Exemption.doc
Existing/Ongoing agricultural activities 1
Removal of dead, terminally diseased, damaged, or dangerous ground cover or hazardous
trees which have been certified as such by a forester, registered landscape architect, or
certified arborist
D Surface Water Alteration:
New surface water discharges provided the discharge meets the requirements of the
Storm and Surface Water Drainage Regulations 12 3
New or modified regional storm water facilities 1 2 3
Flood hazard reduction 1 3 4 6
D Roads, Parks, Public and Private Utilities:
Relocation of Existing Utilities out of Critical Area and Buffer
Maintenance, operation, and repair of existing parks, trails, roads, facilities, and utilities 1 2
Installation, construction, replacement, or operation of utilities, traffic control, and
walkways within existing improved right-if-way or easement 1 2
Modification of existing utilities and streets by 10% or less 1 2 s
Management and essential tree removal for public or private utilities, roads and public
parks 1
D Wetland Disturbance, Modification, and Removal:
Any activity in small Category 3 wetlands 1 2 3 4 5
Temporary disturbances of a wetland due to construction activities that do not include
permanent filling 1 2 3 5
JSt1' Maintenance and Construction for Existing Uses and Facilities:
Remodeling, replacing, or removing existing structures 1 2
Normal and routine maintenance and repair of any existing public or private uses and
facilities where no alteration of the critical area and required buffer or additional fill
materials will be placed 1 2
Construction activity connected with an existing single family residence or garage,
provided that no portion of the new work occurs closer to the critical area or required
buffers than the existing structure 1 2
Existing activities which have not been changed, expanded or altered provided they
comply with the applicable requirements of chapter 4-10 RMC 1
g°' Emergency Activities:
Removal of trees or ground cover by a City department, agency, public, or private utility in
an emergency situation
Public interest emergency use, storage, and handling of hazardous materials by
governmental organizations in an Aquifer Protection Area
ADDITIONAL PERMITS: Additional permits from other agencies may be required. It is the applicant's
responsibility to obtain these other approvals. Information regarding these other requirements may be
found at http://apps.ecy.wa.gov/opas/
-8-04/12
H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Critical Areas Exemption.doc
I, the undersigned, declare under penalty of perjury under the laws of the State of Washington, that to
the best of my knowledge the above information is true and complete.
Applicant Signature:
D Exemption Granted
C.E. "Chip" Vincent, Planning Director
Planning Division
Conditions of Approval:
iExemption does not apply in Aquifer Protection Areas
'Exemption does not apply in Flood Hazard Areas
'Exemption does not apply in Geologic Hazard Areas
'Exemption does not apply in Habitat Conservation Areas
'Exemption does not apply in Streams and Lakes: Class 2 to 4
'Exemption does not apply in Wetlands
-9-
H:\CED\Data\Forms-Templates\Setf-Help Handouts\Planning\Critical Areas Exemption.doc
Date: Q/2-/, 5,,-A(j / 7
D Exemption Denied
Date
04/12
GEOTECHNICAL EVALUATION OF HAZARD
TREE MANAGEMENT PLAN
Pinnacles on Lake Washington
1400 Lake Washington Boulevard North
Renton, Washington
Project No. 1716.00
Novembe r 22, 2016
Prepared for:
Essex Property Trust, Inc.
RECtlVt:D
FEB 1 3 2017 Prepared by :
ZGA
Zipper Geo Associates, LLC
Geotechnical and Environmental Consultants
19023 36th Avenue West, Suite D
Lynnwood, WA 98036
Zipper Geo Associates. LLC
Geotechnical and Environmental Consulting
Essex Property Trust, Inc.
11911 NE 1'1 Street, #8212
Bellevue, Washington 98005
Attention: Mr. Thomas Kachman
Project Number 1716.00
November 22, 2016
Subject: Geotechnical Evaluation of Hazard Tree Management Plan
Pinnacles on Lake Washington
1400 Lake Washington Boulevard North
Renton, Washington 98056
Dear Ms. Kachman,
In accordance with your request and written authorization, Zipper Geo Associates, LLC (ZGA)
has completed a geotechnical evaluation of the Hazard Tree Management Plans prepared by
Arborists NW, LLC and A&M Tree Services NW, Inc. for the Pinnacles on Lake Washington
development located at 1400 Lake Washington Boulevard North in Renton, Washington. This
report presents the findings of our document review and site reconnaissance, and our
geotechnical recommendations for the project. Our services were completed in general
accordance with our Short Form Agreement (Proposal No. P16303) dated October 21, 2016. We
appreciate the opportunity to be of service to you on this project. If you have any questions
concerning this report, or if we may be of further service, please contact us.
Sincerely,
Zipper Geo Associates LLC
JAMES P. GEORGIS
James P. Georgis, L.E.G.
Principal
Copies: Addressee (1)
19023 36th Avenue West, Suite D
,_.,.,,..... , .... •,"· r-"~f '{.:
Thomas A. Jon~ ~-e.r.:' · '·
Principal \=EB 13 20 17
Lynnwood, WA 98036 (425) 582-9928
TABLE OF CONTENTS
Table of Contents
INTRODUCTION ........................................................................................................... 1
SITE DESCRIPTION ..................................................................................................... 1
PROJECT UNDERSTANDING ...................................................................................... 1
GEOLOGIC SETTING ................................................................................................... 2
SITE RECONNAISSANCE ............................................................................................ 3
CONCLUSIONS AND RECOMMENDATIONS ............................................................. 3
General ...................................................................................................................... 3
Trees 1 through 4 (191 through 194) .... ....... . . ................................................ 4
Trees 5 & 6 (195 & 196) ..................................................................................... 5
T~e7(19n ..................................................................................................... 5
Trees 8 & 9 (198 & 199) ...................................................................................... 5
Tree 10 ...................................................................................................................... 6
Geologic Hazard EGA Considerations ....................................................................... 6
Planting Recommendations ....................................................................................... 7
Temporary Erosion Control Considerations ............................................................... 7
Retention of Woody Material. ..................................................................................... 7
General Steep Slope Considerations ......................................................................... 8
CLOSURE ....................................................................................................................... 8
FIGURES
Figure 1 -Site Map
APPENDICES
Appendix A -Undated Arborist Report, prepared by Arborists NW, LLC.
Appendix B -March 27, 2015 Arborist Report, prepared by A&M Tree Services NW, Inc.
FEB 1 3 2'J'il
GEOTECHNICAL EVALUATION OF HAZARD TREE MANAGEMENT PLAN
PINNACLES ON LAKE WASHINGTON
1400 LAKE WASHINGTON BOULEVARD NORTH
RENTON, WASHINGTON
Project No.1716.00
November 22, 2016
INTRODUCTION
This report documents our geotechnical evaluation of the Hazard Tree Management Plans
prepared by Arborists NW, LLC and A&M Tree Services NW, Inc. for the Pinnacles on Lake
Washington development located at 1400 Lake Washington Boulevard North in Renton,
Washington. The project description, site conditions, and our geotechnical conclusions and
recommendations are presented in the text of this report. Supporting data including arborist
reports prepared by others are presented as appendices.
SITE DESCRIPTION
Pinnacles on Lake Washington (Pinnacles) is a multi-building, multi-family residential
development located at 1400 Lake Washington Boulevard North in Renton, Washington. The
Pinnacles development consists of two distinct areas. The upper portion of the development
includes Buildings A through E and is accessed by a private drive off of Lake Washington
Boulevard North. The upper portion of the development is constructed on a relatively level bench
located on a moderately steep to steep west-facing slope. In the central portion of the
development (Building C), the slope extends down from the 1-405 freeway to an off-site multi-
family residential building. In the northern portion of the development (Buildings D and E), the
slope extends down from 1-405 to the lower portion of the Pinnacles development (Building F
through H). Buildings F through H are accessed via North 2ot11 Street. The total relief between
the upper Pinnacles development bench and the bottom of the steep west-facing slope is on the
order of 100 feet. Portions of the steep west-facing slope include near vertical bluffs, some of
which are up to 40 feet tall. The approximate site location, the location of the Pinnacles buildings,
and approximate hazard tree locations are shown on the enclosed Site Map, Figure 1.
PROJECT UNDERSTANDING
The site is mapped by the City of Renton as containing Erosion Hazard, Steep Slope Hazard, and
Landslide Hazard Environmental Critical Areas (ECAs). We understand that the City requires that
a geotechnical evaluation of the Hazard Tree Management Plan be completed to assess the risk
to regulated Geologic Hazard ECAs and their associated buffers, as defined in Part 4-3-050-G-5
of the City of Renton Municipal Code (RMC) that may result from the Hazard Tree Management
Plan and provide recommendations to mitigate identified risks. Our understanding of the project
is primarily based on a review of the following hazardous tree evaluation reports and discussions
with Essex Property Trust.
• Pinnacles on Lake Washington Site, prepared by Arborists NW, LLC., undated.
Zipper Geo Associates. LLC
Pinnacles on Lake Washington
Project No. 1716.00
November 22, 2016
• Pinnacles on Lake Washington, prepared by A&M Tree Service NW, Inc., dated March
27, 2015.
The Arborists NW report appears to predate the A&M Tree Service NW report and identifies a
total of 10 hazard trees comprising two distinct site conditions, as summarized below.
• Trees located on the severely undermined bluff lip: The report identifies Trees 1 through
4 and 8 through 1 O as being severely undermined by the site bluffs with more than half of
their root system either missing or undercut. The report indicates that there is a high risk
that overturning of these trees could pull the top of the bluff down (thereby promoting bluff
regression towards the buildings) and a moderate risk that the treefall (and/or dislodged
soil) could hit the carports below. The report recommends that all of these trees be cut
back to retain their live root system and secure the soil by reducing the weight hanging off
the lip of the bluff. The report indicates that counting on trees to re-sprout is an excepted
method of this type of control and the three main species involved (Red Alder, Big Leaf
Maple, and Cottonwood) are some of the best species for re-sprouting. Tree 8 is a
Douglas Fir and will likely not re-sprout, but is does not appear to be directly addressed in
the Arborists NW report.
• Trees that don't affect the bluff but are a direct hazard to buildings and people: The report
identifies Trees 5 through 7 as not being a significant hazard relative to destabilizing the
bluff, but are a hazard to the buildings and people. The report recommends that Trees 5
and 6 be cut back and allowed to re-sprout, as they are both Big Leaf Maple. Tree 7 is a
deformed, leaning Douglas Fir near Building E. The report recommends structural pruning
or removal and replacement, as re-sprouting of Douglas Fir cannot be relied upon.
A&M Tree Service NW evaluated the 10 hazard trees identified by Arborists NW. However, A&M
only completed tree risk assessments on Trees 1 through 9, as A&M reportedly did not see
significant risk associated with Tree 10. The A&M report identifies the Trees as 191 through 199,
with A&M Tree 191 corresponding to Arborists NW Tree 1. A&M Tree Services NW provided a
tree hazard rating of 8 to 10 for all of the evaluated trees, with the exception of Tree 7 (197)
located at the north end of Building E, which was given a hazard rating of 6. The report
recommends that some of the trees be removed (although not specifically which ones) and that
Trees 6 and 7 (196 and 197) be pruned to remove damaged or defective limbs.
Copies of the two referenced hazard tree reports are enclosed with this geotechnical evaluation.
The approximate locations of Trees 1 through 10 are presented on the Site Map, Figure 1, and ·1n
the Arborists NW report. Photographs of the trees are presented in the A&M Tree Service report.
GEOLOGIC SETTING
We assessed the geologic setting of the site and surrounding vicinity by reviewing The Preliminary
Geologic Map of Seattle and Vicinity, Washington, U.S. Geological Survey Map 1-354, 1962. T_he ... ,,.,
f(· E (·~--;;',:. :; ·:.1 t 0 ·
Page 2
FEB l ::i 2017
Zipper Geo Associates, LLC
Pinnacles on Lake Washington
Project No. 1716.00
November 22, 2016
publication maps the bench on which the upper portion of the Pinnacles development is located
as being mantled by Quaternary age Vashon till (Qt). The Vashon till is generally described as a
compact, unsorted mixture of sand, silt, clay, and gravel, and is commonly referred to as
"hardpan". The lower portion of the steep slope and near vertical bluffs are mapped as older
Quaternary clay till (Qcg). The older clay till is described as sand and gravel lenses in an older
clay till. Both deposits have been glacially over-consolidated and are typically very dense in their
undisturbed, unweathered condition.
SITE RECONNAISSANCE
We completed a reconnaissance of the identified hazard tree locations and immediate vicinity on
November 10, 2016. The purpose of the reconnaissance was to identify surficial features of site
conditions such as the presence or absence of groundwater seepage, the presence or absence
of surface erosion, indications of past slope instability, indications of past land use, the type and
extent of existing vegetation, the location of trees identified for removal/pruning, and other site
features that may be affected by the hazard tree management plan. The enclosed Site Map,
Figure 1, shows the approximate location of the identified hazard trees. Our primary
reconnaissance observations are present in the Conclusions and Recommendations section of
this report.
CONCLUSIONS AND RECOMMENDATIONS
General
The identified hazard trees appear to be located within Erosion Hazard, Steep Slope Hazard, and
Landslide Hazard Environmental Critical Area (ECAs), or their associated buffers. As such, the
Hazard Tree Management Plan must address the effect of the tree management plan on slope
stability.
In general, there are two primary mechanisms which help trees stabilize slopes; 1) mechanical
reinforcement of the soil through roots, and 2) hydrologic effects (reduction of soil water content
through interception and evaporation of precipitation and transpiration). Although the hydraulic
effect of deciduous trees is greatly reduced in the winter (when the potential for slope instability is
generally the highest) due to the reduction in interception (no leaves) and transpiration (trees are
dormant). This winter reduction in the stabilizing effect of trees is much less pronounced in
evergreen trees.
However, it should be noted that large trees located on or near the crest of steep slopes or bluffs
can contribute to slope instability through two primary mechanisms; 1) large trees exposed to wind
can transmit that load to the soil, thereby contributing to slope instability, and 2) the weight of the
tree on the slope or at the crest of a bluff can contribute to slope instability.
Page3
Zipper Geo Associates. LLC
Pinnacles on Lake Washington
Project No. 1716.00
November 22, 2016
There is some debate in the scientific community regarding the relative contributions of these
different factors to slope stability, but the general consensus appears to be that under most
conditions the presence of well-rooted, healthy trees (in particular the bio-reinforcement they
provide) results in a net improvement to slope stability.
Based on the results of our site reconnaissance, document review, and geotechnical analysis, it is
our opinion that the proposed Hazard Tree Maintenance Plan is feasible from a geotechnical
perspective. Provided that the conditions and recommendations contained within this report and
the provisions of the Renton Municipal Code (RMC) are satisfied, it is our opinion that the
proposed Hazard Tree Maintenance Plan will not increase the potential for soil movement and
the risk of damage to existing structures, the site, and to adjacent properties from soil instability
will not be increased.
The following sections provide our conclusions and recommendations regarding the Hazard Tree
Maintenance Plan at specific locations, and a discussion regarding City of Renton regulated ECAs.
Trees 1 through 4 (191 through 194)
These trees are located west of Building C and above the carport and parking lot of the lower
multi-family residential development. Trees 1 and 2 are Big Leaf Maples that exhibit multiple
trunks and appear to have been cut back and allowed to re-sprout at some time in the past. We
could not find a tag positively identifying Tree 3. However, based on the descriptions in the arborist
reports, Tree 3 appears to be a Red Alder. Tree 4 is a relatively large Big Leaf Maple with two
trunks.
Trees 1 through 4 are located at the top of a steep landslide feature, which in turn is located
immediately above a near vertical bluff on the order of 30 to 40 feet tall. The bluff generally
consists very dense, poorly sorted silty sand to sandy silt with variable gravel content interpreted
as glacial till. The landslide above the bluff appears to have occurred in weathered till soils and
terminates in a near vertical head scarp on the order of 3 to 8 feet tall. The head scarp extends
up to and partially below the trunks of Trees 1 through 3, and is about 1 foot away from the trunk
of Tree 4.
It is our opinion that the landslide head scarp which has undermined these trees is marginally
stable and the weight and wind loading effect of these trees could trigger a landslide resulting in
down slope deposition of soil and wood debris (which could potentially impact the carport area)
and upslope regression of the landslide feature. In our opinion, cutting these trees back and
allowing them to re-sprout as generally recommended in the arborist reports would retain the soil
reinforcement of the live root system while reducing the loading conditions promoting slope
instability and result in a net increase in slope stability. We recommend that cut-wood be
prevented from cascading down the scarp or near vertical bluff, as this condition could contribute
to erosion and instability.
Page4
Zipper Geo Associates. LLC
Pinnacles on Lake Washington
Project No. 1716.00
November 22, 2016
Trees 5 & 6 (195 & 196)
Trees 5 and 6 are large Big Leaf Maple trees and have been identified in the arborist reports as
a potential hazard to Building C. Both trees are located on a 30-to 50-degree slope which exhibits
irregular, hummocky topography and is interpreted as older colluvium (landslide material). In our
opinion, cutting these trees back and allowing them to re-sprout or reducing their size and weight
by selective pruning as recommended in the arborist reports would retain the soil reinforcement
of the live root system while reducing the loading conditions promoting slope instability and result
in a net increase in slope stability.
Tree 7 (197)
Tree 7 is a Douglas Fir located north of Building E. The tree is located near the crest of a 20 to
30-degree slope and appears to be leaning towards the building. We did not observe obvious
surficial indications of past slope instability in this area. The arborist reports appear to recommend
structural pruning or removal and replacement of this tree. In our option, both options appear
feasible from a geotechnical perspective. Douglas Fir cannot be relied upon to re-sprout and
maintain a live root system after cutting. If the tree is removed, we recommend that the stump
and root system by left in place and that a new tree be planted nearby to establish a new root
system as the roots of the cut tree decompose and lose their effectiveness as soil reinforcement
over time.
Trees 8 & 9 (198 & 199)
Trees 8 and 9 are located west of Building E and above the carport and parking lot area for
Building H. Tree 8 is a Douglas Fir and Tree 9 is a Cottonwood. The trunks of these trees are
separated by about 1 foot and likely have an interdependent root system. Trees 8 and 9 are
located at the top of a near vertical bluff on the order of 6 to 8 feet tall. The bluff generally consists
very dense, poorly sorted silty sand to sandy silt with variable gravel content interpreted as glacial
till. The bluff has partially undermined the trunks of both trees.
It is our opinion that the bluff which has undermined these trees is marginally stable and the weight
and wind loading effect of these trees could trigger a landslide resulting in down slope deposition
of soil and wood debris (which could potentially impact the carport area) and upslope regression
of the landslide feature. In our opinion, removing the Douglas Fir and cutting the cottonwood back
and allowing it to re-sprout as recommended in the arborist reports would retain the soil
reinforcement of a portion of the live root system while reducing the loading conditions promoting
slope instability and result in a net increase in slope stability. We recommend that cut-wood be
prevented from cascading down the scarp or near vertical bluff, as this condition could contribute
to erosion and instability. We recommend that the stump and root system of the Douglas Fir be
left in place and that a new tree be planted to establish a new root system as the roots of the cut
tree decompose and lose their effectiveness as soil reinforcement over time. We recommend that
the new tree be planted at least 6 feet from the top of the bluff to establish a new root system as
Page 5
Zipper Geo Associates. LLC
Pinnacles on Lake Washington
Project No. 1716.00
November 22, 2016
the roots of the cut Douglas Fir tree decompose and lose their effectiveness as soil reinforcement
over time.
Tree 10
The Arborists NW report identified Tree 1 Oas a severely leaning hazard tree located below Trees
1 and 2. The tree appears to be located where the landslide feature described in the Tree 1 and
2 area terminates at the top of the 30-to 40-foot-tall near vertical bluff. This tree does not appear
to be identified as a hazard in the A&M Tree Service report. In our opinion, selective pruning of
this tree to reduce its weight and wind loading characteristics while retaining the live root system
would result in a net increase in slope stability. However, the tree is located in a difficult to access
and precarious position on the slope. In our opinion, pruning of the tree should not be undertaken
if accessing the area would result in significant disturbance of the ground surface or would put
workers at risk.
Geologic Hazard ECA Considerations
The site is mapped by the City of Renton as containing Erosion Hazard, Steep Slope Hazard, and
Landslide Hazard Environmental Critical Areas (ECAs). ZGA completed a geotechnical
evaluation of the Hazard Tree Maintenance Plan to assess the risk to regulated Geologic Hazard
ECAs and their associated buffers, as defined in Part 4-3-050-G-5 of the City of Renton Municipal
Code (RMC) that may result from the planned maintenance and provide recommendations to
mitigate identified risks.
Part 4-3-050-C-3 of the RMC indicates that the removal/pruning of dangerous trees which have
been approved by the City and certified dangerous by a licensed landscape architect or certified
arborist is exempt from RMC ECA restrictions and may be permitted by the Ctty. The following
sections present our evaluation of Erosion Hazard, Steep Slope Hazard, and Landslide Hazard
ECA's relative to the Hazard Tree Removal/Pruning Plan.
Erosion Hazard Areas: The City of Renton maps the planned hazard tree maintenance areas as
Erosion Hazard ECA's. Based on our document review and site reconnaissance, tt is our opinion
that the planned hazard tree maintenance areas meet the RMC Erosion Hazard Area criteria.
Steep Slope Hazard Areas: The City of Renton maps the planned hazard tree maintenance areas
as Steep Slope Hazard Areas with slope inclinations ranging from 25 to 40 percent slopes and 40
to 90 percent slopes. Based on our site reconnaissance, it is our opinion that the planned hazard
tree maintenance areas meet the RMC Steep Slope Hazard Area criteria.
Landslide Hazard Areas: Wtth the exception of the Tree 7 area, the Ctty of Renton maps the planned
hazard tree maintenance areas as Moderate Severity Landslide Hazard Areas. The Tree 7 area is
not mapped as a Landslide Hazard Area. Based on our document review and site reconnaissance
Page 6
Zipper Geo Associates, LLC
Pinnacles on Lake Washington
Project No. 1716.00
November 22, 2016
observations, it is our opinion that the planned hazard tree maintenance areas (excluding the Tree
7 area) meet the RMC Landslide Hazard Area criteria.
Risk Evaluation Summary: Provided that the conditions and recommendations contained within
this report and the provisions of the Renton Municipal Code (RMC) are satisfied, it is our opinion
that the proposed Hazard Tree Maintenance Plan will not increase the potential for soil movement
and the risk of damage to existing structures, the site, and to adjacent properties from soil
instability will not be increased.
Planting Recommendations
Douglas Fir trees are not expected to re-sprout. As previously discussed, we recommend that a
new tree be planted near Tree 8. We also recommend that a new tree be planted near Tree 7 if
Tree 7 is cut off near the ground surface and not pruned. Based on our review of the arborist
reports, it appears that the other identified hazard trees will be cut back and allowed to re-sprout
or will be structurally pruned. It is possible that a tree may not re-sprout or that a pruned tree may
not survive. Based on our evaluation of the site conditions, it is our opinion that the decay of the
root systems associated with Trees 1 through 6 could result in a localized reduction in the stability
of the slope near the decaying root system. Research indicates that the soil reinforcing benefit of
the root mass may only last three to nine years after a tree has died. Therefore, we recommend
that the project arborist inspect Trees 1 through 6 an appropriate time interval after cutting to
verify that the trees are re-sprouting as intended and/or recovering from the pruning process. If
a tree is determined to be dead or dying, we recommend that at least two new trees be planted
in its place. We recommend that the species of new tree planted be determined by the project
arborist based on the site conditions at the planting location.
Temporary Erosion Control Considerations
We anticipate that the tree cutting process will likely result in disturbance of the ground surface
and a temporary increase in the potential for erosion. We therefore recommend that the tree
removal service utilize means and methods intended to minimize ground disturbance. In addition,
we recommend that soils exposed within Steep Slope Hazard Areas and their buffers be covered
with a temporary erosion control material, such as sterile straw or arborist mulch.
Retention of Woody Material
In our opinion it appears geotechnically feasible to retain much of the woody debris generated
from the hazard tree maintenance as habitat enhancement within wooded portions of the site.
However, we recommend that woody material greater than 6-inches in diameter be prevented
from falling down or accumulating on the steep slopes or bluffs located below Trees 1 through 4,
and 8 and 9.
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Zipper Geo Associates. LLC
Pinnacles on Lake Washington
Project No. 1716.00
November 22, 2016
General Steep Slope Considerations
Owners of properties containing or adjacent to steep slopes should recognize that soil loss or
downslope displacement from steep slopes is a naturally occurring mass wasting process, and
that some soil loss from steep slopes should be expected over time, particularly in response to
episodic severe storm events. The conclusions and recommendations presented in this report are
intended to allow for the cutting/removal of hazard trees while maintaining the existing stability of
the site slopes. The findings presented in this report should not be interpreted as indicating that
the site steep slopes will be stable under all possible future conditions.
CLOSURE
This report has been prepared for the exclusive use of Essex Property Trust. Inc., and their
agents, for specific application to this project and has been prepared in accordance with generally
accepted geotechnical engineering practices. No warranties. express or implied, are intended or
made. Site safety is the responsibility of others. In the event that changes in the nature, design,
or location of the tree removal/pruning as outlined in this report are planned, the conclusions and
recommendations contained in this report shall not be considered valid unless Zipper Geo
Associates, LLC reviews the changes and either verifies or modifies the conclusions of this report
in writing.
Page 8
REFERENCE : GOOG LE EARTH 2016. NOT TO SCALE
RECE,VtD
FEB 13 ZC 17
PINNACLES ON LAKE WASHINGTON
1400 Lake Wash ing to n Boulevard North
Renton , Washing~on
Site Map
DATE November 2016 Job No
Zipper Geo Associates, LLC FIGURE
19023 36th Ave . W .Su ite D
Lyn nwood , WA SHT . 1 of 1
171 6.00
1
APPENDIX A
ARBORISTS NW, LLC REPORT
~EB 1 3 2017
Bill Rehe
Pinnacle on Lake Washington site
arboristsN\N, 1_1_c
FEB 1 3 ZG\7
www. a rbo ri sts 11 w. com
P.O. Box 909
Mercer Island, WA 98040
(206) 779-2579
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I have personally inspected several trees at "Pinnacle on Lake Washington"
complex as you requested. Keeping in mind your desire to create a long term
plan for the trees and land around and on the property I used a International
Society of Arboriculture level 1 Limited visual assessment. Jeff from Tolt Tree care
had pointed out 6 trees in particular. I added 4 trees after a closer look at the
original trees. The trees I will discuss are now tagged and number 1-10 find the
attached maps with their locations.
Of the trees there are 2 different situations, trees on the severally undermined lip
of the bluff which I would call coastal if it was closer to lake Washington which is
across Lake Washington Blvd. from the complex. The western edge of the
property·still has the look of a coastal wasting Bluff. The species involved are Red
Alder, Cottonwood, Big Leaf Maple and 2 Douglas firs (#'s 1, 2, 3, 4, 8, 9 and 10).
The second situation, trees hazardous to the building and people (#5, 6 Big Leaf
Maples and 7 a Douglas fir)
One of the trees that I added to my inspection was particularly interesting (#10).
This tree appears to be a remnant of the last large scale slough off of material on
this vertical face. The trunk of the tree is growing downhill and would be lying on
the ground if there was any under it and is in the 18-22" DBH range. In my
opinion this tree was a small sapling at the time of the last slough off stayed
rooted in the new precipice then flourished after a period of stress and die back.
In observing the tree fr~m the west one can see the original stem now dead and
in the 3-4" diameter range about 10' long then the old remaining live trunk. This
trunk is in the same size range as the trees in the debris field (Noting the size of
the trees in the debris field below a wasting bluff is a method of determining
major wasting events, my opinion is 25-30 years ago). There are 2 leaders that
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FEB 1 3 ZU'}
look like trees growing out of the original trunk with slightly smaller DBH's then
the trees in the debris field 22-25" DBH.
Now to the trees on what I will call the lip of the slope. 2 trees numbered 1, 2 are
stump sprouted Big Leaf Maples having several trunks and are severally
undermined with more than half of their root systems either missing or under cut.
Trees with this problem also include number #'s 3, 4 andlO above Red Alders, #8
a Douglas fir, #9 a Cottonwood. Numbers 3, 4 8, 9 are normally shaped trees.
Number 4 has a 45% lean and bow sweep
All of these trees in my opinion need cut back to let them retain their live root
systems and secure the soils buy reducing the weight hanging off the lip of the
bluff. This mitigation can add years if not decades to the position of the bluff edge
and slows its creep towards the buildings on the property.
Counting·.on trees to re-sprout is an excepted method of this type of control and
the 3 main species involved are some of the best at re-sprouting. Red Alder, Big
Leaf maple and Cottonwood.
So the trees as hazards; There is a high risk of pulling the top face of the bluff
down and a moderate risk to fall far enough to hit the carport of the apartments
below, That is if just the top lip and the trees fall. This in no way addresses a
larger landslide. Trees numbered 1, 2, 3, 4, 8, 9, and 10
Now to the trees that don't affect the bluff but are hazardous to the buildings
proper. There are 2 BLMs with extensive past branch and scaffold branch failures.
One has extensive stump decay #5 the other a 25' -30' spiral crack in the trunk #6
showing the intensity of the winds effect on this tree. Both of these trees are on
the windward side of the building and within 35' of it. One tree is in the 125' tall
(6) range the other in the 80' range (5). I would give these trees a hazard rating of
12 on the older ISA hazard form out of a possible 12. Tree 6 could last until
spring but after the leaves reemerge any winds may cause the tree to fail. Tree
eEB 1 3 ?017
number 5 with the severe stump rot in my opinion should be mitigated as soon as
possible! Fortunately both trees can be counted on to re-sprout keeping their
root systems alive.
Tree number 7 a Douglas fir on the far north of the property has lost its top and is
now deformed with one large apically dominating branch now growing towards
the building and within 15'. Structural pruning or possible removal and
replacement of this tree would be the methods of mitigating this situation.
In closing structural pruning, cutting for re-sprout and replacement trees or
shrubs are the methods of mitigation to help you in your plan to manage the
wasting bluff, stand stability and reduce hazardous conditions near the buildings.
Respectfully Submitted
Neal Baker
ArboristsNW.com
ISA Cert PN1075A
ISA Tree Risk Assessment Qualified
PNW ISA CTRA #867
Member AREA & SOCA
206 779 2579
A&M Tree Semce NW, Inc.
Commercial & Residential Services
March 27, 2015
Pinnacle at Lake Washington
c/o Bill Rehe
1400 Lake Washington Blvd N
Renton, WA 98056
FEB 1 3 2017
Thank you for the opportunity to help you with your tree needs. Attached is the report and
the hazard evaluations that you requested.
If you have any questions regarding this report l can be reached on my cell phone at
425-770-3040.
Sincerely,
Michael A Morey Jr.
A & M Tree Service NW, Inc.
ISA Certified Arborist #PN-6934A
ISA TRAQ 1794
425-867-2307
• Arborist Report for Pinnacle at Lake Washington
Prepared by Mike Morey Jr. PN-6934A TRAQ# 1794
A&M Tree Semce NW, Inc.
Commercial & Residential Services
FEB 1 3 2017
Scope ofWork
On March 27, 2015 I visited the property at 1400 Lake Washington Blvd N also known as
Pinnacle at Lake Washington apartments to do a review of several already identified trees.
I have over 18 years in the industry. I am a Certified Arborist as well as a Qualified Tree
Risk Assessor which is also known as TRAQ. This qualification from the International
Society of Arboriculture (ISA) allows me to assess the risk of your tree(s). My visual
assessments include a rubber mallet, a spade, a field microscope, binoculars, Stanley tape
measure, and pruning shears and a digital laser rangefinder.
Observation:
This is an established property located both on a hillside as well as at the base of said
hillside. The areas between the two are separated by a critical area containing a steep
slope (the hillside) which is where the trees identified in this report are located. The
vegetation is mostly blackberry, alder, cottonwood and maple with some fir and cedar here
and there.
Discussion:
There were a total of 10 trees identified; however, I only did tree risks on 9 as I did not see
any risk involved in the 10th identified tree. My findings are as follow ...
Tag# Species DBH # of trunks Condition Hazard Racine
191
192
193
194
195
196
197
198
199
Acer Macrophvllum 20" 9 Compromised root svstem/slone
Acer Macrophvllum 20" 7 Compromised root svstem/slooe/soil
Alnusrubra 26" 1 Comoromised root svstemlslooe
Acer Macrophvllum 48" 2 Comnromised root svstem/slone
Acer Macrophyllum 40" 2 Compromised root system/slope/multi
5mTintoms
Acer Macrophvllum 40" 1 Comnromised root svstem/slone
Pseudotsuea menziesii 11" 1 Slight curve at ton
Pseudotsu2:a rnenziesii 16" 1 Compromised root svstem/slone/soil
Populus 20" 1 Comoromised root svstern/slone/soil
• Arborist Report for Pinnacle at Lake Washington
Prepared by Mike Morey Jr. PN-6934A TRAQ# 1794
10
10
9
8
10
8
6
8
10
A&M e
Tree Senlce NW, Inc.
Commercial & Residential Services
Conclusion/Recommendations:
R£(:':[J\!ED
FEB 1 3 2017
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Pt,, ...
Several trees do need to be removed and left for habitat. This work needs to be completed
with a certified arborist on site. I would also suggest that a certified arborist climb and
inspect tree #196 and remove only damaged and defective limbs. Tree #197 should have
reduction cuts made on th e maple branches to a llow for better growth. I would also
suggest that you have a geotechnical engineer evaluate the slope area further in the near
future .
Below are pictures to help identify the trees ....
Arborist Report for Pinnacle at Lake Washington
Prepared by Mike Morey Jr. PN -693 4A TRAQlt 1794
A&M Tree Sentce NW, Inc.
Commercial & Residential Services
Arborist Report for Pinnacle at Lake Was hington
Prepared by M ik e Mor ey Jr. PN-6934A TRAQ# 1794
RECttVED
FEB 1 3 2017
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arboristsN\N, tLc
www. arbor is tsn w. com
P.O. Box 909
Bill Rehe , .·· r , :.xMercer Island, WA 98040
' 'i ;~. ,· ' f l_ <kc<'
'·" ·~ (206) 779-2579
Pinnacle on Lake Washington site FEB l 3 2G17
I have personally inspected several trees at "Pinnacle on Lake Washington"
complex as you requested. Keeping in mind your desire to create a long term
plan for the trees and land around and on the property I used a International
Society of Arboriculture level 1 Limited visual assessment. Jeff from Tait Tree care
had pointed out 6 trees in particular. I added 4 trees after a closer look at the
original trees. The trees I will discuss are now tagged and number 1-10 find the
attached maps with their locations.
Of the trees there are 2 different situations, trees on the severally undermined lip
of the bluff which I would call coastal if it was closer to lake Washington which is
across Lake Washington Blvd. from the complex. The western edge of the
property·still has the look of a coastal wasting Bluff. The species involved are Red
Alder, Cottonwood, Big Leaf Maple and 2 Douglas firs (#'s 1, 2, 3, 4, 8, 9 and 10}.
The second situation, trees hazardous to the building and people (#5, 6 Big Leaf
Maples and 7 a Douglas fir}
One of the trees that I added to my inspection was particularly interesting (#10).
This tree appears to be a remnant of the last large scale slough off of material on
this vertical face. The trunk of the tree is growing downhill and would be lying on
the ground if there was any under it and is in the 18-22" DBH range. In my
opinion this tree was a small sapling at the time of the last slough off stayed
rooted in the new precipice then flourished after a period of stress and die back.
In observing the tree from the west one can see the original stem now dead and
' in the 3-4" diameter range about 10' long then the old remaining live trunk. This
trunk is in the same size range as the trees in the debris field (Noting the size of
the trees in the debris field below a wasting bluff is a method of determining
major wasting events, my opinion is 25-30 years ago). There are 2 leaders that
FES 1 3 2017
look like trees growing out of the original trunk with slightly smaller DBH's then
the trees in the debris field 22-25" DBH.
Now to the trees on what I will call the lip of the slope. 2 trees numbered 1, 2 are
stump sprouted Big Leaf Maples having several trunks and are severally
undermined with more than half of their root systems either missing or under cut.
Trees with this problem also include number #'s 3, 4 andlO above Red Alders, #8
a Douglas fir, #9 a Cottonwood. Numbers 3, 4 8, 9 are normally shaped trees.
Number 4 has a 45% lean and bow sweep
All of these trees in my opinion need cut back to let them retain their live root
systems and secure the soils buy reducing the weight hanging off the lip of the
bluff. This mitigation can add years if not decades to the position of the bluff edge
and slows its creep towards the buildings on the property.
Counting·.on trees to re-sprout is an excepted method of this type of control and
the 3 main species involved are some of the best at re-sprouting. Red Alder, Big
Leaf maple and Cottonwood.
So the trees as hazards; There is a high risk of pulling the top face of the bluff
down and a moderate risk to fall far enough to hit the carport of the apartments
below, That is if just the top lip and the trees fall. This in no way addresses a
larger landslide. Trees numbered 1, 2, 3, 4, 8, 9, and 10
Now to the trees that don't affect the bluff but are hazardous to the buildings
proper. There are 2 BLMs with extensive past branch and scaffold branch failures.
One has extensive stump decay #5 the other a 25' -30' spiral crack in the trunk #6
showing the intensity of the winds effect on this tree. Both of these trees are on
the windward side of the building and within 35' of it. One tree is in the 125' tall
(6) range the other in the 80' range (5). I would give these trees a hazard rating of
12 on the older ISA hazard form out of a possible 12. Tree 6 could last until
spring but after the leaves reemerge any winds may cause the tree to fail. Tree
F[1! 1 '.1 2017
: ,-n N,
number 5 with the severe stump rot in my opinion should be mitigated as soon as
possible! Fortunately both trees can be counted on to re-sprout keeping their
root systems alive.
Tree number 7 a Douglas fir on the far north of the property has lost its top and is
now deformed with one large apically dominating branch now growing towards
the building and within 15'. Structural pruning or possible removal and
replacement of this tree would be the methods of mitigating this situation.
In closing structural pruning, cutting for re-sprout and replacement trees or
shrubs are the methods of mitigation to help you in your plan to manage the
wasting bluff, stand stability and reduce hazardous conditions near the buildings.
Respectfully Submitted
Neal Baker
ArboristsNW.com
ISA Cert PN1075A
ISA Tree Risk Assessment Qualified
PNW ISA CTRA #867
Member AREA & SOCA
206 779 2579