HomeMy WebLinkAboutLUA16-000330_MiscPRELIMINARY TECHNICAL INFORMATION-REPORT~----------
for
Finley Short Plat
2525 Aberdeen Ave NE
Renton, WA 98056
March 11, 2016
Revised on August 8, 2016
Encompass Engineering Job No. 15615
Prepared For
2525 Aberdeen, LLC
13110 NE 177th Place #202
Woodinville, WA 98072
Westem Washbtgton Division Eastern Washington Division
, 165 NE Junipcr St., Ste 201, Issaquah, WA 98027 108 East 200 Street, Cle Elwn, WA 98922
Phone: (425) 392-0250 Fax: (425) 391-3055 Phone: (509) 674-7433 Fax: (509) 674-7419
www.EncompassES.net
TABLE OF CONTENTS
SECTION 1 -PROJECT OVERVIEW
FIGURE 1
TIR Worksheet
FIGURE2
Sile Location
FIGURE 3
Drainage Basins, Sub-Basins & Site Characteristics
SECTION 2 -CONDITIONS AND REQUIREMENT SUMMARY
SECTION 3 -OFFSITE ANALYSIS
SECTION 4 -FLOW CONTROL & WATER QUALITY ANALYSIS
SECTION 5 -CONVEYANCE SYSTEM ANALYSIS & DESIGN
SECTION 6 -SPECIAL REPORTS & STUDIES
SECTION 7 -OTHER PERMITS
SECTION 8 -TESC ANALYSIS & DESIGN
SECTION 9-BOND QUANTITIES, FAC. SUMMARY & DEC. OF COVENANT
SECTION 10 -OPERATIONS & MAINTENANCE MANUAL
APPENDIX A -GEOTECHNICAL REPORT
APPENDIX B -ARBORIST REPORT
APPENDIX C -KCRTS ANALYSIS
Site Address:
King County Tax Parcel:
2525 Aberdeen Ave NE, Renton WA, 98056
334390-2000, 334390-2021
I. PROJECT OVERVIEW
This project involves the development of two existing parcels with a total area of0.61 acre into
four single-family lots. A boundary line adjustment will be made to the existing two parcels and
the larger of the two adjusted parcels will then be subdivided into three lots for a total of four
lots. The boundary line adjustment and 4-lot short plat will occur concurrently. The first parcel
(#334390-2000) contains an existing home with various retaining walls, driveway, concrete
walk, shed, carports, grass/brush and about 54 significant trees. The second parcel (#334390-
2021) contains a few small concrete pads, an existing shed and some retaining wall. The
majority of the site slopes downward toward the east property limit at slopes of approximately
2% to 40%. A small portion along the north and west property limits drain toward the north and
northwest at slopes ranging from 17"/o to 71 %. Per the Natural Resources Conservation Service
Soil Survey, the site is underlain with Indianola loamy sand. A geotechnical engineering study
was also performed to verify infiltration and the report has been attached.
Figure 1
KING COUNTY, WASHI1'GTON, SCRFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER
Project Owner 2525 Aberdeen, LLC
Phone-----------~
Address 13110 NE 177th Place #202
Woodinville, WA 98072
Project Engineer Chad Allen, PE
Company Encompass En&ineerin& & Surveying
Phone 425-392-0250
Part 3 TYPE OF PERMIT APPLICATION
!El Landuse~
Subdivison ~ UPD
CJ Building Services
M/F / Commerical / SFR
!El Clearing and Grading
CJ Right--0f-Way Use
CJ Other
Part5 PLAN AND REPORT INFORMATION
Technical Information Report
Type of Drainage Review @ Targeted
(circle): Large Site
Date (include revision
dates):
Date of Final:
Part 6 ADJUSTMENT APPROVALS
I
Part 2 PROJECT LOCATION AND
DESCRIPTION
Project Name Finley Short Plat
ODES Permit# ----------
Location Township _2_3_N ___ _
Range _.....:.5~E'----~
Section 5 -~'------
Site Address 2525 Aberdeen Ave NE
Renton, WA 98056
Part 4 OTHER REVIEWS AND PERMITS
CJ DFWHPA
CJ COE 404
CJ DOE Dam Safety
CJ FEMA Floodplain
CJ COE Wetlands
CJ Other __ _
CJ Shoreline
Management
CJ Structural
RockeryNaulV __
CJ ESA Section 7
Site Improvement Plan (Engr. Plans)
Type (circle one): ~/ Modified I
I Site
Date (include revision
dates):
Date of Final:
Type (circle one): ~ Complex / Preapplication / Experimental/ Blanket
Description: (include conditions in TIR Section 2)
Date of Annroval:
2009 Surface Water Design Manual 1/9/2009
KING COUNTY, WASHl1'GTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes@ Describe:
Start Date: NIA
Completion Date:
Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan : ...;N;.,-;-ew......;;.cas=.,tI,.,e,,...,.. ________ _
Special District Overlays: _N...,,_./1 A....__ ____________________ _
Drainage Basin: ...,....M_a~y_C_re_e_k _________ _
Stormwater Requirements: ______________________ _
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
0 River/Stream ----------
0 Lake
0 Wetlands __________ _
0 Closed Depression --------0 Floodplain __________ _
0 other ___________ _
Part 10 SOILS
Soil Type Slopes
0 Steep Slope ---------
0 Erosion Hazard --------
0 Landslide Hazard--------
0 Coal Mine Hazard--------
0 Seismic Hazard --------
0 Habitat Protection-------0 _________ _
Erosion Potential
InC 5 to 15 percent Low to Moderate
0 High Groundwater Table (within 5 feet) 0 Sole Source Aquifer
0 Other 0 Seeps/Springs
0 Additional Sheets Attached
2009 Surface Water Design Manual
2
1/9/2009
KING COUNTY, WASHINGTON, SCRFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE LIMITATION/ SITE CONSTRAINT
l]I !;;ore 2 -Qffsite Anal~sis
Q Sensitive/Critical Areas
Q SEPA
Q Other
Q
Q Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summarv Sheet =r Threshold Discharoe Area\
Threshold Discharge Area:
(name or description-) TDA-l
Core Requirements (all 8 apply)
Oischaroe at Natural Location Number of Natural Discharae Locations: 2
Offsite Analysis Level: (__!_) 2 / 3 dated:
Flow Control Level:~2 / 3 or Exemption Number
(incl. facilitv summarv sheet) Small Site MPs
Conveyance System Spill containment located at: Contractor Shed
Erosion and Sediment Control ESC Site Supervisor: TBD Contact Phone:
After Hours Phone:
Maintenance and Operation Responsibility: C Private)/ Public
If Private, Maintenance Loa Reauired: Yes /No'\
Financial Guarantees and Provided: Yes / No
Liabilitv By Owner
Water Quality Type: Basi / Sens. Lake / Enhanced Basicm / Bog
(include facility summary sheet) or Exemptio 0.
Landscaoe Manaaement Plan: Yes KNol
Special Requirements las annlicable\
Area Specific Drainage Type: CDA / SOO /MOP/ BP/ LMP / Shared Fae, I None
Reauirements Name: NIA
Floodplain/Floodway Delineation Type: Major I Minor I Exemption I None
100-year Base Flood Elevation (or range): NIA
Datum:
Flood Protection Facilities Describe: NIA
Source Control Describe landuse: NIA (commJindustrial landuse) Describe any structural controls:
2009 Surface Water Design Manual 1/9/2009
3
KING COUNTY, WASHINGTON, SCRFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE LIMITATION I SITE CONSTRAINT
l!J Qore 2 -Qffsit!;l Anal~sis
D Sensitive/Critical Areas
D SEPA
D Other
D
D Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet cer Threshold Discharne Area I
Threshold Discharge Area:
(name or descriotion\ TDA-2
Core Requirements (all 8 apply)
Discharge at Natural Location Number of Natural Discharae Locations: 2
Offsite Analysis Level: (__!.) 2 I 3 dated:
Flow Control Level:~2 / 3 or Exemption Number
(incl. facility summarv sheet) Small Site MPs
Conveyance System Spill containment located at: Contractor Shed
Erosion and Sediment Control ESC Site Supervisor: TBD Contact Phone:
After Hours Phone:
Maintenance and Operation Responsibility: C Private)/ Public
If Private, Maintenance Loa Reauired: Yes rliio"'i
Financial Guarantees and Provided: 0::!)I No
Liability By Owner
Water Quality Type: Basi I Sens, Lake / Enhanced Basicm / Bog
(include facility summary sheet) or Exemptio 0.
Landscaoe Manaaement Plan: Yes l'No)
Soecial Reauirements las annlicablel
Area Specific Drainage Type: CDA I SDO I MDP /BP/ LMP I Shared Fae./ None
Reauirements Name: NIA
Floodplain/Floodway Delineation Type: Major / Minor I Exemption / None
100-year Base Flood Elevation (or range): NIA
Datum:
Flood Protection Facilities Describe: NIA
Source Control Describe landuse: NIA (comm./industrial landuse) Describe any structural controls:
2009 Surface Water Design Manual 1/9/2009
3
KING COUNTY, WASHIM..iTON, SLRFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Oil Control High-use Site: Yes/~
Treatment BMP: N/A
Maintenance Agreement: Yes '®
with whom?
Other Drainaae Structures
Describe:
N/A
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION AFTER CONSTRUCTION
!ii Clearing Limits !ii Stabilize Exposed Surfaces
!El Cover Measures !]I Remove and Restore Temporary ESC Facilities
!El Perimeter Protection D Clean and Remove All Silt and Debris, Ensure
D Traffic Area Stabilization Operation of Permanent Facilities
D Sediment Retention D Flag Limits of SAO and open space
D Surface Water Collection
preservation areas
D Other D Dewatering Control
D Dust Control
D Flow Control
Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facilitv Summarv and Sketch)
Flow Control T vne/Descri ption Water Qualitv Tvne/Descriotion
D Detention D Biofiltration
!El Infiltration Infiltration Basins D Wetpool
D Regional Facility D Media Filtration
D Shared Facility D Oil Control
D Flow Control D Spill Control
BMPs D Flow Control BMPs D Other D Other
2009 Surface Water Design Manual
4
1/9/2009
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 15 EASEMENTSfTRACTS Part 16 STRUCTURAL ANALYSIS
CJ Drainage Easement CJ Cast in Place Vault
Cl Covenant CJ Retaining Wall
CJ Native Growth Protection Covenant -13-Rockery>-4'-High
~ Tract Cl Structural on Steep Slope
Cl Other Cl Other
Part 17 SIGNATURE OF PROFESSIONAL ENGINEER
I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were
incorporated into this worksheet and the attached Technical lnfonmation Report. To the best of my
knowledge the Information provided here is accurate.
e,t--( 1~"""-----8/q//6
Sinnfld/Date
2009 Surface Water Design Manual
5
1/9/2009
\
\
\
/
/
The nformation ~ckJded on lhis map has been compiled by King Co1Jnly slaff'from a variety of source s a'ld ,s
9.Jb,e<;t to change wthout nohoe Kng County makes no representations or warnrities. express or 1m p1ed
as to acx:uracy.compleleness. lmelness. or nghts to tre use of wch inforrnatio, Tt'i s tilcument1s r'Qt n:~ded
bl' uw asa survey product King County sha l rot be Hable fer any general, special. rldired, 1nodensa _ :)r
consequential damages indudflg. but net J1mted to lost re-,.enues or lost profi~ resut ing from the use or "'n ~se
rlthe 1nfonnahon cmtained on this map /J.ny sale ofthsmilp orinfonnaticn on thi s map is proh,b ted e~~e::>t by
wnt en petT1"11ss1a, of K1~ County
Date : 2/24/2016 Notes: Parcels 3343902000, 3343002021
Figure 2
til King County
GISCENTER
__,..._ Wcrarsht~<l Bounca-y
-..../-Basin Boun,Jo·y
Riv"'
Stream
i
4Mll ,n
tfowt!n,tx:r JOlJ
The
Lake Washington/Cedar River
Watershed
l_P~oject Sit~
tQ King County
Departme nt o f Natural Reso urces a nd Par ks
Water and Land Resources Division
Procluc..:I by:
Ii; ng CO>iril)' IT ~ ... ,.c.,, Cit; ,J ,uJ I Con•rr~nkil'.•on'> .-rte Wt,t, ~ecr;on
F,~ lf(UY'r~ 1211_,2t,SO_(c(fatL.Wolsh M.1p ill s,, .. 11
'Tl
(JQ
C
@
w >
Figure 3B
City of Renton Storm Sewer Atlas
II. CONDITIONS AND REQUIREMENTS SUMMARY
Conditions and Requirements
Provide Full Infiltration per 2009 KC SWDM Section C.2.2:
• Section C.2.2.2 -Minimum Design Requirements for Full Infiltration.
• Section C.2.2.1 and C.2.2.4
o Figure C.2.2.C
CORE REQUIREMENTS
Core Requirement #1: Discharge at the natural Location
Runoff generally sheet flows across the site in an easterly direction. Refer to the Level 1
Downstream Analysis in Section 3 for a complete description of the existing drainage path.
Core Requirement #2: Offsite Analysis
An offsite drainage analysis is provided in Section 3 of this TIR. Level 1 Drainage Analysis has
been prepared and no problems identified.
Core Requirement #3: Flow Control
This project qualifies for Full Drainage Review. The proposed project site will produce more
than 5,000 square feet of new impervious surfaces. Flow control BMPs for infiltration will
provide the required flow control for proposed improvements.
This site has two distinct drainage areas (TD1 & TD2) and various flow control BMP's will be
used to control the site's runoff. TDA-2 at the northwest area of the site consists of green space
and a portion of the paved access driveway. At TDA-1, storm water run-off tributary to the
paved access driveway will be allowed to infiltrate through the use of two infiltration basins. The
remainder of the site area will consist of 3 new homes, new driveways and an access drive.
Mitigation of surface run-off for these areas will be performed through the use of filter strips for
the driveways and infiltration basins the remaining impervious areas.
Core Requirement #4: Conveyance System
Conveyance system analysis and design is provided in Section 5 of the TIR.
Core Requirement #5: Erosion and Sediment Control
A temporary erosion and sediment control (TESC) plan provides BMPs to be implemented
during construction.
Core Requirement #6: Maintenance and Operations
See Section X -Operation and Maintenance Manual
Core Requirement #7: Financial Guarantees and Liability
The owner will arrange for any financial guarantees and liabilities required by the permit.
Core Requirement #8: Water Quality
Refer to section 8 of this TIR for Water Quality Analysis and Design
SPECIAL REQUIREMENTS:
Special Requirement #1: Other Adopted Area-Specific Requirements
Critical Drainage Area -N/A
Master Drainage Plan -N/A
Basin Plan -This site is located within the May Creek drainage basin
Lake management Plan -NIA
Shared Facility Drainage Plan -N/A
Special Requirement #2: Floodplain/Floodway Delineation
The limits of this project do not lie in a 100-year floodplain
Special Requirement #3: Flood Protection Facilities
This special requirement is required for projects with Class 1 or 2 streams with an existing flood
protection facility. The site does not contain any streams and is therefore not applicable.
Special Requirement #4: Source controls
This project is a 4-lot single-family residential project and this requirement is not applicable.
Special Requirement #5: Oil Control
This project is not considered high-use in need of oil control.
Ill. OFF-SITE ANALYSIS
Downstream Drainage Analysis
Existing Conditions
Encompass Engineering & Surveying performed a level I downstream analysis for this project on
both TD A's. There are 2 threshold discharge areas on these parcels. Runoff generally drains in
the northeast direction across both parcels. A small portion of surface run-off drains toward the
north/northwest limits of parcel 3343902021.
Nonheast TDA #J (Approximate Area .c 2.J.J/8.50 ~!):
Runoff draining toward the northeast discharge location will sheet flow toward the western edge
of Aberdeen Avenue and flow north along the road until it reaches a Catch Basin, located at
point (A), which is approximately 10 feet away from the discharge location. From there, the
flow travels along the closed conveyance system for approximately 30 feet to a second catch
basin located at point (B), located along the edge of Aberdeen Ave. From there, the flow
continues northward until it reaches a manhole at point (C) which is located at the intersection of
Aberdeen Ave and NE 26th Place. The flow then travels westward toward a stormwater
detention facility at point (E) which is located at the western end of NE 26th Place. The flow is
then conveyed westward toward catch basins located at point (F), point (G) and point (H). After
point (H), the flow is conveyed through the closed conveyance system to point (I) which is
located within the eastern end of NE 26th Street. At that point, the flow is directed northward
until it reaches a manhole located at point (J) and then flows into a manhole at point (K). The
flow then travels northwest until it reaches a manhole at point (L) which is located at the
intersection of NE 28th Street and Kennewick Pl NE and which is more than one-quarter mile
downstream of the site's discharge location. The flow is then conveyed northwest through a
series of storm sewer pipes until it reaches NE 30th Street and then conveyed east/northeast until
it discharges into May Creek which ultimately drains into Lake Washington. There were no
apparent downstream drainage problems or erosion issues identified during the downstream
drainage analysis.
NortWNonhwest TDA #2 (Approximate Area~ 1971.25 ~:
The Runoff discharging from the site at the north and northwest property limits are conveyed to a
stormwater detention facility through sheet flow toward NE 26th Place where the stormwater is
collected into a stormwater inlet located at point (E), which is within the south curb-line of NE
26th Place and then conveyed into the stormwater detention facility, which is located at the
western end of NE 26th Place. At this point, the flow has converged with the flow from the
Northeast Discharge Location (TDA-1) Since the 2 threshold discharge areas converge within
V. mile, it is considered a single discharge location. The combined flow is then conveyed toward
the west. There were no apparent downstream drainage problems or erosion issues identified
during the downstream drainage analysis.
Developed Conditions
Runoff from the proposed roof area within each new lot will be directed to basins for full
infiltration of all roof runoff. Proposed dri veway runoff for each lot will be mitigated through
filter strips along the edge of each driveway The access drive that will connect individual
driveways to Aberdeen A venue will be con structed of permeable pavement with flow barriers
installed at 5.5 foot interval s to capture runoff and allow for full infiltration. The existing home
on the subject site was built in 1962 and wi 11 re main intact after the proposed improvements and
boundary line adjustment. Since the ho me was constructed prior to the implementation of water
quality and flow control requirements, runoff for the lot containing the existing home is not
required to be mitigated.
Photo 1: Stormwater inlet locat ed near the northeast corner of the subject property
Photo 2 : C urb Inlet locate d in So uth C urb-lin e of NE 26th Place
Photo 3 : Stormwater Dete ntion Facil ity located at the west end of NE 26th Place
Photo 4 : Storm Manhol e located in pavem e nt of NE 2611' Street
Photo 5: Storm Manholes located in pavement of NE 27th Street
Photo 6: Storm Manholes located in Kennewick Pl NE near intersection of NE 28th Street
IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
Drainage Design
This project wi ll invo lve adding approximately 1,186 sq-ft of new impervious surface in the
public R/W, so flow control is not being propo sed for the improvements in the public R/W.
Runoff from the new frontage improve ments wil l be routed into the existing CB/pipe storm
system in Aberdeen Avenue NE .
Infiltration BMP's will be pro vided for ne w roof surfaces on the lots and for the access driveway
to allow for full infiltration of the runoff New driveways for each lot will have a filter strip
located along the downstream edge of each to mitigate storm runoff KCRTS analysis for the
proposed infiltration basins is shown in Ap pendix C.
The access driveway contains approximat ely 3 ,060 sq-ft of PGIS and approximate area for each
of the three individual driveways is 50 0 sq-ft each for a total of 4,560 of new PGIS which is
below the 5,000 sq-ft threshold for require ment of water quality treatment . Therefore, water
quality treatment will not be needed for this project.
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Since the small infiltration basins will a ll ow for full infiltration up to a 100-year storm event, a
conveyance syste m analysis is not required as the flow rate through the proposed sewer would be
zero. The onsite conveyance system is only being provided to provide protection against an
infiltration device failure.
VI. SPECIAL REPORTS AND STUDIES
Geotechnical Engineering Report
Arborist Report
VII. OTHER PERMITS
Building permits will be required.
VIII. TESC ANALYSIS AND DESIGN
The potential for erosion within the site will be mitigated by use of erosion control measures
during clearing, grading, and site development activities. Filter fences will be installed along the
downhill perimeter of the site to protect adjacent properties from sediment-laden water. A
rocked construction entrance will be installed at the entrance to the site to protect mud from
entering the paved roadway. Stockpiles and exposed disturbed areas will be covered to protect
from erosion and sediment runoff
Element I: Mark Clearing Limits.
All clearing, grading, sensitive areas, and buffers will be clearly marked in the field prior to
construction in accordance to the plans and specifications. Prior to beginning land disturbing
activities, including clearing and grading, clearly mark all clearing limits, sensitive areas and
their buffers, and trees that are to be preserved within the construction area. These shall be
clearly marked, both in the field and on the plans, to prevent damage and offsite impacts. Plastic,
metal, or stake wire fence may be used to mark the clearing limits.
Element 2: Establish Construction Access.
Construction access will be provided for the site. Driveway re-alignment should be completed
after all other construction is complete. Stabilize the construction access with rock per the
stormwater plans if the driveway is disturbed. Access points shall be stabilized with a pad of
quarry spalls, crushed rock, or equivalent BMP prior to traffic leaving the construction site to
minimize the tracking of sediment onto all roads and accesses.
Element 3: Control Flow Rates.
Flow rates from the construction site are not expected to negatively impact the downstream
corridor. A temporary sediment pond is not being proposed as part of this project, however other
sediment retention BMPS are being proposed as part of Element 4. At all times, flow rates shall
be controlled for this project. Natural drainage patterns shall be protected as much as possible
during construction, and concentrated flow should not be permitted. Properties and waterways
downstream from development sites shall be protected from erosion due to increases in the
volume, velocity, and peak flow rate ofstormwater runoff from the project site.
Element 4: Install Sediment Controls.
Silt fence should be used to protect all sensitive area slopes. Soils should be covered if not
worked for 7 days during the dry season or 2 days during the wet season. The street should be
swept each night or as required. If the minimum BMPs fail to retain sediment to the sight,
additional BMPs will be used.
Element 5: Stabilize Soils.
Soils shall be covered if not worked for 7 days during the dry season or 2 days during the wet
season. Soil stockpiles will be covered unless worked. Soil stockpiles shall be located away from
drain inlets and surface water discharge locations. Soil stockpiles shall be stabilized and covered
as needed or removed to an approved disposal site. Soils shall be stabilized at the end of the shift
before holidays or weekends if needed based on weather forecast.
Element 6: Protect Slqpes.
The site has a steep even slope to the west property limit. Slope protection is anticipated. In the
event that erosion does occur along the edges of the project, energy dissipater (flow spreaders)
shall be used or the surface water will be routed away from the slopes.
Element 7: Protect Drain Inlets.
There are existing catch basins located downstream of the project. Filter fabric protection shall
be used for sediment control.
Element 8: Stabilize Channels and Outlets.
Existing or proposed channels or drainage outlets are not components of this project, thus
stabilization of these elements are not required
Element 9: Control Pollutants.
Pollution generated from construction must be controlled at all times. Control of pollutants other
than sediments includes the following:
• All pollutants other than sediments shall be handled and disposed of in a manner that
does not cause contamination of stormwater.
• Cover, containment and protection from vandalism shall be provided for all chemicals,
liquid products, petroleum products, and non-inert wastes present on the project site.
• Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic
system drain down, solvent and de-greasing cleaning operations, fuel tank drain down
and removal, and other activities which may result in discharge or spillage of pollutants
to the ground or into stormwater runoff must be conducted using spill prevention
measures, such as drip pans. Contaminated surfaces shall be cleaned immediately
following any discharge or spill incident. Emergency repairs may be performed on-site
using temporary plastic placed beneath and, if raining, over the vehicle.
• Wheel wash or tire bath wastewater shall be discharged to a separate on-site treatment
system or to the sanitary sewer, if available.
Element 10: Control De-Watering.
De-watering is not anticipated for the site. In the event that dewatering is necessary, storm shall
be treated such that sediment remains on site. This shall be done by routing the storm water
through a straw filter, silt fence, and/or sediment trap.
Element 11: Maintain BMPs.
BMPs shall be inspected monthly and after every significant storm event, Sediment shall be
removed from the BMPs as necessary for them to continue operating at the required performance
level. In the event that a BMPs has been damaged, it shall be replaced immediately.
Element 12: Manage the Project.
Construction activities shall be phased such that the impact to the area will be kept at a
minimum Coordination will occur with all utility agencies that are affected by this project.
BMPs shall be inspected regularly and after each significant storm event. The Contractor will
provide a Certified Erosion and Sediment Control Specialist. If for any reason a BMPs is not
sufficient for the project, additional BMPs will be installed.
IX. BOND QUANTITIES and DECLARATION of COVENANT
Bond Quantities
To be provided in Final Engineering
Facility Summaries
To be provided in Final Engineering.
Declaration of Covenant
Declaration of Covenant for maintenance will have to be approved and recorded.
X. OPERATION AND MAINTENANCE MANUAL
Operations and Maintenance Instructions for Basic Infiltration
Your property contains a stormwater management flow control BMP (best management practice)
called "basic dispersion," which was installed to mitigate the storm.water quantity and quality
impacts of some or all of the impervious surfaces or non-native pervious surfaces on your
property. Basic dispersion is a strategy for utilizing any available capacity of onsite vegetated
areas to retain, absorb, and filter the runoff from developed surfaces. This flow control BMP has
two primary components that must be maintained:
( 1) The Infiltration devices from the developed surfaces
Your property contains a stormwater management flow control BMP (best management practice)
called "full infiltration," which was installed to mitigate the stormwater quantity and quality
impacts of some or all of the impervious surfaces on your property. Full infiltration is a method
of soaking runoff from impervious area (such as paved areas and roofs) into the ground. If
properly installed and maintained, full infiltration can manage runoff so that a majority of
precipitation events are absorbed. Infiltration devices, such as gravel filled trenches, drywells,
and ground surface depressions, facilitate this process by putting runoff in direct contact with the
soil and holding the runoff long enough to soak most of it into the ground. To be successful, the
soil condition around the infiltration device must be reliably able to soak water into the ground
for a reasonable number of years.
The infiltration devices used on your property include the following as indicated on the flow
control BMP site plan: C gravel filled trenches, u drywells, D ground surface depressions. The
size, placement, and composition of these devices as depicted by the flow control BMP site plan
and design details must be maintained and may not be changed without written approval either
from the King County Water and Land Resources Division or through a future development
permit from King County. Infiltration devices must be inspected annually and after major storm
events to identify and repair any physical defects. Maintenance and operation of the system
should focus on ensuring the system's viability by preventing sediment-laden flows from
entering the device. Excessive sedimentation will result in a plugged or non-functioning facility.
If the infiltration device has a catch basin, sediment accumulation must be removed on a yearly
basis or more frequently if necessary. Prolonged ponding around or atop a device may indicate a
plugged facility. If the device becomes plugged, it must be replaced. Keeping the areas that drain
to infiltration devices well swept and clean will enhance the longevity of these devices. For
roofs, frequent cleaning of gutters will reduce sediment loads to these devices.
APPENDIX A
GEOTECHNICAL REPORT
Ucotcdmica l Engineering
Ucolob'Y
E m·ironmcntal Scientists
Construction Monitoring
GEOTECHNICAL ENGINEERING STUDY
PROPOSED SHORT PLAT
2525 ABERDEEN AVENUE NORTHEAST
RENTON , WASHINGTON
ES-4338
PREPARED FOR
MR. WILLIAM HEGGER
MARCH 7, 2016
~rw~ ~ T. Wright, E.I.T
Project Engineer
Raymond A. Coglas, P.E.
Principal
GEOTECHNICAL ENGINEERING STUDY
PROPOSED SHORT PLAT
2525 ABERDEEN AVENUE NORTHEAST
RENTON, WASHINGTON
ES-4338
Earth Solutions NW, LLC
1805 -1361h Place Northeast, Suite 201
Bellevue, Washington 98005
Phone: 425-449-4704 Fax: 425-449-4711
Toll Free: 866-336-8710
Important lnlormation About Your
Geotechnical Engineering Report
Suos,1,/ace pcnhlem5 aie J nnnupal cause of co11struct1,m deli!'!' , ost 1ve,111ns claim:, a:w 1for111/P-.1 • Thr folio~ ma 01urmatJan 1s prov1da•d to nel{) vou nunaoP H'll' ;1,1;s
Gaotectmlcal Services Are Performed for
Specfflc Purposes, Pers1ns, and Projects
Geotechnical engineers structure their services to meet the specific needs of
their clients. A geotechnical engineering study condUGted for a civil engi-
neer may not fulfill the needs of a construction contractor or even another
civil engineer. Because each geotechnica engineering study is unique, each
geotechnical engineering report is unique, prepared solely for the client. No
one except you should rely on your geotechnical engineering report without
first ccnferring with the geotechnical engineer who prepared it. And no one
-not even you-should apply the repM tor any purpose or pro/eel
except the one originally contemplated.
Read the Full Report
Serious problems have occurred because those relying on a geotechnica,
engineering report did not read it all. Do not rely on an executive summary.
Do not read selected elements only.
A Geotechnical Eni,11-::r' Is Based on
A Unique Set ol ProJect Factors
Geotechnical engineers ccnsider a number of unique, project-specific fac-
tors when establishing the scope of a study. Typical factors mc'ude: the
client's goals, ob1ectives, and risk management preferences; the general
nature of the structure involved, its size, and configuration; the locatim1 oi
the structure on the site; and other planned or existing site improvements,
such as access roads, parking lots, and underground utilities. Unless the
geolechnical engineer who conducted the study specifically indicates oth-
erwise, do not rely on a geotechnical engineering report that was:
• not prepared for you,
• not prepared for your project,
• not prepared for the specific site eJ<plored, or
• completed before important project changes were made.
Typical changes that can erode the reliability of an existing geotechnical
engineering report include those that affect:
• the function of the proposed structure, as when it's changed from a
parking garage to an office building, or from a light industr:al plant
to a refrigerated warehouse,
• elevation, ccnfiguration, location, orientation, or weight of the
proposed structure,
• composition of the design team, or
• project ownership.
As a general rule, always inform your geotechnical engineer of project
changes---Bven minor ones-and request an assessment of their impact.
Geotechnical engineers cannot accept responsibility or liability for problems
t/Jat occur because /heir reports do not consider developments of which
they were not informed.
Subsll'lace Comltlllls Can Change
A geotechnical engineering report is based on ccnditions that existed at
the time the study was pertormed. Do not roly on a geoteclmical engineer-
ing repo/twhose adequacy may have been affected by: the passage of
ti;ne; by man-made events, such as construction on or adjacent to the site;
or by natural events, such as floods, earthquakes, or groundwater fluctua-
tions. Always contact Ille geotechnical engineer before applying the report
to determine if it is still reliable. A minor amount of additional testing or
analysis could prevent major problems.
Most Geotechnical Rndings Are Proleaional
Opinions
Site exploration identifies subsurface conditions only at those points where
subsurface tests are conducted or samples are taken. Geotechnical engi-
neers review field and laboratory data and then apply their professional
judgment to render an opinion about subsurface conditions throughout the
site. Actual subsurface conditions may differ-sometimes significantly-
from those indicated in your report. Retaining the geotechnical engineer
who developed your report to provide construction observation is the
most effective method of managing the risks associated with unanticipated
conditions.
A Report's Recommendatin Are Notfinal
Do not overrcly on the construction recommendations included in your
report. Those rocommendations are not lina( because geotechnical engi-
neers develop them principally from judgment and opinion. Geotechnical
engineers can finalize tlieir recommendations only by observing actual
subsurface conditions revealed dunng construction. The geatechmca!
engineer who developed your report cannot assume responsibility or
liability for the report's recommendations if that engineer does not perform
construction observation.
A Geotechnical Engineering Report Is Subiect to
Misinterpretation
Other design team members' misinterpretation of geotechnical engineering
reports has resulted in costly problems. Lower that risk by having your geo-
technical engineer confer with appropriate members of the design tmm arter
submitting Ille report. Also retain your geotectmical engineer to review perti·
nent elements of the design team's plans and speci'ications. Ccntractors can
atsc misinterpret a geotechnicat engineering report. Reduce that risk by
having your geotechnical engineer participate in prebid and precons:ruction
conferences, and by providing construction observation.
Do Not Redraw the Engineer's Logs
Gectechnical engineers prepare final boring and testing logs basea upon
their interpretation of field togs and laboratory data. To prevent ,rrors or
omissions, the logs included in a geotechnical engineering report s1oulj
never be redrawn for inclusion i,1 architectural or other d€sign drawings.
Only photographic or electronic reproduction is acceptable, but recognize
that separating logs from the repolf can elevate risk.
Give Contractors a Complete Report and
Guidance
Some owners and design professionals mistakenly believe they can make
contractors liable for unanticipated subsurtace conditions by limiting what
they provide for bid preparation. To help prevent costly problems, give con-
tractors 1he complete geotechnical engineering report, but preface it "Nith a
clearly written letter of transmittal. In that letter, advise contractJrs that the
report was not prepared for purposes of bid development and that the
report's accuracy is limited; encoursge them to confer with the geotechnical
engineer who prepared the report (a modest fee may be required) and/or to
conduct additional study to obtain the specific types of informat,on they
need or prefer. A prebid conference can also be valuable. Be surn contrac·
tors have sufficient lime to pertorm additional study. Only thEn might 10,
be in a position to give contractors the best information available to you,
while requiring them to at least share some of the financial responsib;lities
stemming from unanticipated conditions.
Read ResponslblilY Provisions Closely
Some clients, design professionals, and contractors do not :ecognize that
geotechnical engineering is far less exact than other engineerino di sci·
plines. This lack of understanding has created unrealistic expectatrors th1.t
have led to disappointments, claims, and disputes. To help reduce the risk
of such outcomes, geotechnicat engineers commonly include a variety of
explanatory provisions in their reports. Sometimes labeled "limitations"
many of these provisions indicate where geotechnical engineers' responsi·
bilities begin and end. to help others recognize their own responsibilities
and risks. Read these provisions closely Ask questions. Your geotechnical
engineer should respond fully and frankly.
Geoenvironmental Concerns Ara Not Covered
The equipment, techniques, and personnel used to pertorm a geoenviron-
mentalstudy differ significantly from those used to pertorm a geotechnical
study. For that reason, a geotechnicat engineering report does not usuatty
relate any geoenvironmental findings, conclusions, or recommendations;
e.g., about the likelihood of encountering undergrocnd storage tanks or
regulated contaminants. Unanticipated environmental problems have led
to numerous project failures. If you have not yet obtained your own gcoen·
vironmental information, ask your geotechnical consultant for risk man·
agement guidanCB. Do nor rely on an environmental report prepared for
someone else.
Obtain Professional Assistance To Deal with Mold
Diverse strategies can be applied during building design, construction,
operation, and main;enance to prevent significant amounts of mold from
growing on indoor surfaces. To be effective, all such strategies should be
devised for the express purpose of mold prevention, integrated into a com·
prehensive plan, and executed with diligent oversight by a professional
mold prevention consultant. Because just a small amount of water or
moisture can lead to the development of severe mold infestations, a num-
ber of mold prevention strategies focus on keeping building surtaces dry.
While groundwater, water infiltration, and similar issues may have been
addressed as part of the geotechnicat engineering study whose findings
are conveyed iri-this report, the geotechnical engineer in charge of this
project is not a mold prevention consultant; none of the services per-
formed in connection with the geotechnicaf engineer's study
were designed or conducted for the purpose of mold preven-
tion. Proper implementation of the recommendations conveyed
in this rBport will no/ of Itself be sufficient to prevent mold from
growing in or on the structure involved.
~ on Your ASFE-Mllmller Gellechnclal
e• lor Adllllonal Assls1lnce
Membership in ASFE/The Best People on Earth exposes geotechnical
engineers to a wide array of risk management techniques that can be of
genuine benefit for everyone involved with a construction project. Confer
with you ASFE-member geotechnical engineer for more information.
A5FE
Tin 1851 Pnate U IUIII
8811 Colescille Rcaj/Suite G106, Silver Spring, MD 20910
Telephone 3011565·2!33 Facsimile: 301/589-2017
e-l"ilaii: info@asfP..org www.asfe.org
Copyriy/lt 2004 tJy ASFE, fnr;. Duplication, reproduction, ar copying of r/Jis document. in wM/e ar in part, by any means whatsoever; is strictly prohibited, except with ASFE's
sp{leiffc written permission. Excerpting, quoting, or otnerwise exrractmg wording from fflis document is permitted only with the express written permission of ASFE, and anfy tor
purposes of scholarly research or book ravir,w, Only mombers of ASH: may use this documer,t as a complement to or as an element of a geotechnicaJ engmeerino report Any other
firm, individual, or other f!ntity that so uses this docum,mt without heir1g :m AS!--E mflm/Jer could /Je committina negllfJMt ar intentiOflal (trauau1ent) misrepresenta.tian.
IIGER06045 OM
March 7, 2016
ES-4338
Mr. William Hegger
13110 Northeast 177th Place, #203
Woodinville, Washington
Dear Mr. Hegger,
Earth Solutions NW LLC
• Ceotcchnical Engineering
• Construction Monitoring
• Environmental Sciences
Earth Solutions NW, LLC (ESNW) is pleased to present this report titled "Geotechnical
Engineering Study, Proposed Short Plat, 2525 Aberdeen Avenue Northeast, Renton,
Washington".
In our opinion, development and construction of the proposed short plat residential
development is feasible from a geotechnical standpoint. Following site preparation and grading
activities, the proposed building structures can be supported on conventional spread and
continuous footings bearing on recompacted native soil or new structural fill. We recommend
uniformly compacting exposed building slab and footing subgrade areas prior to forming and
pouring concrete to create a uniform support condition. Based on our understanding of the
proposed development, competent native soils suitable for support of foundation should be
encountered at depths of between approximately two to three feet below existing grades.
Recommendations for site preparation and related earthwork activity, structural fill placement,
foundation and retaining wall design, subsurface drainage, and other pertinent geotechnical
recommendations are provided in this study.
We appreciate the opportunity to be of service to you on this project. If you have any questions
regarding the content of this geotechnical engineering study, please call.
Sincerely,
EARTH SOLUTIONS NW, LLC
~ Henry T. Wright, E.I.T.
Project Engineer
180S -13Gth Place N.E., Suitl::' 2.0"! • B~l •'\·'.1t-. \-\-A g80fl.S • (42S\ 449-4704 • FAX i425i 449-4711
Table of Contents
ES-4338
PAGE
INTRODUCTION............................. .. . . . . . . . . .. .. .. . . .. . .. . .. . .. . .. . .. .. .. 1
General....................................................................... 1
Project Description................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SITE CONDITIONS................................ . .. . . . .. . .. . . . . .. . .. . . . . .. . .. .... 2
Surface....................................................................... 2
Subsurface . . . .. . .. . .. . .. . . .. . . . .. . . .. .. . .. .. .. . .. . .. . .. . .. . .. . . .. . .. . . . . .. 2
Topsoil.............................................................. 3
Native Soils........................................................ 3
Geologic Setting................................................. 3
Groundwater............................................................... 3
INFILTRATION EVALUATION................................................... 3
Infiltration Recommendations....................................... 4
GEOLOGICALLY HAZARDOUS AREAS... .. . .. .. . .. . .. .. .. .. . .. .. . .. ... 4
Steep Slope Designation............................................... 4
Landslide Hazard Designation....................................... 5
Erosion Hazard Designation.......................................... 5
Seismic Hazard Designation................................................. 5
Buffer and Building Setback.......................................... 5
DISCUSSION AND RECOMMENDATIONS.................................. 5
General........................................................................ 5
Site Preparation and General Earthwork........................... 6
Temporary Erosion Control................................... 6
In-situ Soils......................................................... 6
Imported Soils..................................................... 6
Rockeries and Modular Block Walls....................... 7
Subgrade Preparation......... .. ... .................. ......... 7
Structural Fill....................................................... 7
Foundations .. . . . . .. . .. .. . .. .. .. .. . . . .. . .. .. .. .. .. . . .. ... .. . . .. .... ........ 7
Seismic Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Slab-On-Grade Floors..................................................... 8
Retaining Walls.............................................................. 8
Drainage...................................................................................... 9
Excavations and Slopes...... . .. . .. .. . . .. . . . . . . . .. . . . . . . .. . . . . . . . . . . ... . 10
Pavement Sections........................................................ 10
Utility Support and Trench Backfill................................... 11
Earth Solutions NW, LLC
Table of Contents
Continued
ES-4338
PAGE
LIMITATIONS....................................................................... 11
Additional Services . . . . . . . . .. .. .. . .. .. .. .. .. . . . . . . . . .. . . .. . . . . . . .. . .. .. 11
GRAPHICS
Plate 1
Plate 2
Plate 3
Plate 4
APPENDICES
Appendix A
Appendix B
Vicinity Map
Test Pit Location Plan
Retaining Wall Drainage Detail
Footing Drain Detail
Subsurface Exploration
Test Pit Logs
Laboratory Test Results
Grain Size Distribution
Earth Solutions r-N-1, LLC
GEOTECHNICAL ENGINEERING STUDY
PROPOSED SHORT PLAT
2525 ABERDEEN AVENUE NORTHEAST
RENTON, WASHINGTON
ES-4338
INTRODUCTION
General
This geotechnical engineering study was prepared for the three new residential lots to be
developed to the west of the existing house located at 2525 Aberdeen Avenue Northeast in
Renton, Washington. The purpose of this study was to perform subsurface explorations across
accessible portions of the site, conduct appropriate analyses, and prepare geotechnical
recommendations for the proposed development. Our scope of services for completing this
geotechnical engineering study addressed the following:
• Preparing a site geologic description including soil and groundwater conditions that
may impact site development;
• Providing project-specific recommendations regarding site grading, drainage,
structural fill requirements, erosion control, recommended pavement sections;
• Providing soil bearing capac'ity, subgrade preparation, and other pertinent
recommendations for foundation support;
• Preparing an assessment of the suitability of the site soils for use as structural fill;
• Preparing a critical area evaluation with respect to slope areas within and adjacent to
the subject site;
• Preparing an infiltration evaluation based on in-situ infiltration testing to provide
infiltration design recommendations, and;
• Providing additional geotechnical recommendations, as appropriate.
The following documents and maps were reviewed as part of our report preparation:
• Online Web Soil Survey (WSS) resource maintained by the United States Department
of Agriculture (USDA), Natural Resources Conservation Service;
• Geologic Map of King County, compiled by Derek B. Booth, Kathy A. Troost, & Aaron
P. Wisher, dated March 2007;
• Site Plan, prepared by Encompass Engineering & Surveying, dated January 18, 2016;
and
• 2009 King County Surface Water Design Manual (Renton).
Mr. William Hegger
March 7, 2016
Project Description
ES-4338
Page2
We understand that the subject site will be developed with three new residential lots to be
constructed to the west of the existing house, an access roadway, and associated
improvements; we understand the existing house will remain. The proposed buildings will likely
be constructed utilizing relatively lightly loaded wood framing supported on conventional
foundations. Final building loads were not available at the time of this report. Based on our
experience with similar projects, we anticipate perimeter footing loads on the order of 1 to 2 kips
per lineal foot (kif) for each structural story. Slab-on-grade loading is anticipated to be on the
order of 150 pounds per square foot (psf).
Based on the existing topography, grading will likely consist of cuts of up to six to ten feet to
complete construction of the buildings on lots 1 and 2. We anticipate rockeries and/or modular
block retaining walls will be utilized to accommodate lot grading.
We understand infiltration systems will be utilized to accommodate the site stormwater. The
infiltration systems will likely consist of trenches or drywells within the lots and permeable
pavement for the proposed access road.
If the above design assumptions are incorrect or change, ESNW should be contacted to review
the recommendations in this report. ESNW should review the final design to verify that our
geotechnical recommendations have been incorporated.
SITE CONDITIONS
Surface
The site is located at 2525 Aberdeen Avenue Northeast in Renton, Washington. The
approximate location of the property is illustrated on plate 1 (Vicinity Map). The site consists of
two residential tax parcels (King County parcel numbers 3343902000 and 3343902021) totaling
approximately 0.60 acres of land area. The site is currently developed with a single-family
residence and consists primarily of yard areas and lightly forested land. The majority of the site
is relatively level with a rockery to the north of the site and landscape block walls throughout the
site. There is a slope area of greater than 40 percent slope which is less than approximately 1 O
feet in height to the west-northwest of the site.
Subsurface
An ESNW representative observed, logged, and sampled four test pits on February 11, 2016
excavated at accessible locations within the property using a mini-trackhoe and operator
retained by our firm. The test pits were completed for purposes of assessing soil conditions,
classifying site soils, and characterizing subsurface groundwater conditions within the proposed
development area. In-situ infiltration testing was completed at two of the test pit locations.
Earth Solutions tiM/, LLC
Mr. William Hegger
March 7, 2016
ES-4338
Page 3
The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan).
Please refer to the test pit logs provided in Appendix A for a more detailed description of
subsurface conditions.
Topsoil
Topsoil was observed in the upper approximately 4 to 12 inches of existing grades. Topsoil
was characterized by dark brown color, the presence of fine organic material, and small root
intrusions. Topsoil is not suitable for use as structural fill nor should it be mixed with material to
be used as structural fill. Topsoil or otherwise unsuitable material can be used in landscape
areas if desired.
Native Soils
Underlying topsoil, the native soils encountered at the test pit locations consisted primarily of
medium dense poorly graded sand with gravel (Unified Soil Classification System SP)
recessional outwash deposits extending to the maximum exploration depth of 11.5 feet below
existing grades. USDA textural classification identified these soil types as slightly gravelly to
extremely gravelly coarse sand. Native soils were encountered primarily in a moist condition.
Geologic Setting
The referenced geologic map resource indicates the site and surrounding areas are underlain
by recessional outwash deposits (Qvr). Recessional outwash deposits generally consist of
relatively "clean" sand and gravel deposits. The soil conditions observed were consistent with
recessional outwash sand and gravel deposits.
The referenced WSS resource identifies Indianola loamy sand surficial soils (map unit lnC)
across the site and surrounding areas. Indianola loamy sand soils indicate sand deposits
(USDA classification) at a depth beginning at approximately one and one-half to two feet below
grade. The soil conditions encountered at the test pit locations were consistent with outwash
Indianola soils.
Groundwater
Groundwater was not observed at the time of our fieldwork on February 11, 2016. We do not
anticipate the project will be significantly impacted by groundwater, however, perched interflow
may be encountered in deeper site excavations. Groundwater seepage rates and elevations
fluctuate depending on many factors, including precipitation duration and intensity, the time of
year, and soil conditions. In general, groundwater flow rates are higher during the wetter,
winter months.
INFILTRATION EVALUATION
As part of our study, we performed an infiltration evaluation for the proposed infiltration facilities.
We understand the storm drainage for the proposed project will be designed using the 2009
King County Surface Water Design Manual (KCSWDM).
Earth Solutions NW, LLC
Mr. William Hegger
March 7, 2016
ES-4338
Page4
We understand lot infiltration using infiltration trenches or drywells and an infiltration system for
the proposed access road will be utilized to accommodate stom,water.
Infiltration Recommendations
The soil conditions encountered throughout the majority of the site consisted of slightly gravelly
to extremely gravelly coarse sand (USDA classification). Per 2009 KCSWDM, in-situ infiltration
testing was completed at test pit locations TP-1 and TP-2 at representative depths; a shallow
modified PIT was completed at TP-1 to characterize infiltration capacity of upper weathered
soils for the proposed pem,eable pavement, EPA falling head infiltration testing was completed
at TP-2 to characterize the infiltration capacity of the underlying "clean" sand and gravel
outwash. Based on the soil conditions observed and the results of the in-situ infiltration testing,
we recommend the following parameters for design of the infiltration facilities:
Infiltration Trench -Lots
Infiltration Drywalls -Lots
Infiltration Rate -Lots
Infiltration Rate -Permeable Pavement
*Includes a total correction factor of greater than 10.0
20 ft. per 1,000 sq. ft. of Impervious
60 cu. ft. per 1,000 sq. ft. of
Impervious
20 in./hr.*
1.5 in./hr.**
**Representative of upper weathered sand soil, Includes a total correction factor of 8.0
We recommend implementing an overflow provision in the design of the proposed infiltration
facilities; if an overflow provision is not incorporated in the design of the proposed infiltration
facilities, we recommend reducing the above design parameters by a factor of 2. ESNW should
observe the excavation of the infiltration facilities to confirm the anticipated soil conditions.
GEOLOGICALLY HAZARDOUS AREAS
As part of this geotechnical engineering study, Section 4-3-050 (CRITICAL AREAS
REGULATIONS) of the Renton Municipal Code was reviewed with respect to geologically
hazardous areas. Based on City of Renton online mapping, a sensitive slope area is mapped
to the west-northwest of the subject site.
Steep Slope Designation
A sensitive slope designation is based on a 25 to 40 percent slope and a 40 percent or greater
slope with an elevation change of less than 15 feet. The portion of the slope to the west-
northwest of the site with a gradient of 40 percent or greater is across an elevation change of
less than approximately 10 feet, and is therefore consistent with a sensitive slope designation.
Earth Solutions NW, LLC
Mr. William Hegger
March 7, 2016
Landslide Hazard Designation
ES-4338
Page 5
Per Renton Municipal Code, a portion of the sensitive slope area located to the west-northwest
of the subject classifies as a high landslide hazard based on a slope gradient of greater than 40
percent, however, the majority of the sensitive slope area classifies as a medium landslide
hazard. In our opinion, the landslide potential of the sensitive slope area can be classified as
very low based on the limited nature of the slope area and the relatively stable nature of the
sand and gravel soils.
Erosion Hazard Designation
The Indianola series soils classify as having a low to moderate erosion potential. In this
respect, the site soils present a low erosion hazard. In our opinion, the erosion potential of the
site soils will be mitigated with typical construction BMPs.
Seismic Hazard Designation
The seismic hazard of the site soils classify as low seismic hazard based on a seismic design
classification of D.
Buffer and Building Setback
Based on the above designations, per Section 4-3-050.G.2. of the Renton Municipal Code, the
subject project is not subject to any critical area buffers or setbacks. In our opinion, the
geologically hazardous potential for the subject site can be considered very low.
DISCUSSION AND RECOMMENDATIONS
General
Based on the results of our study, construction of the proposed residential structures at the site
is feasible from a geotechnical standpoint. The primary geotechnical considerations associated
with the proposed development include foundation support, slab-on-grade subgrade support,
and minimizing post-construction settlements.
Based on the results of our study, the proposed building structures can be supported on
conventional spread and continuous footings bearing on recompacted native soil or new
structural fill. We recommend uniformly compacting building slab and footing subgrade areas
prior to forming and pouring concrete to create a uniform support condition. Based on our
understanding of the proposed development, competent native soils suitable for support of
foundation should be encountered at depths of between approximately two to three feet below
existing grades. Where loose or unsuitable soil conditions are exposed at foundation subgrade
elevations, compaction of the soils to the specifications of structural fill, or overexcavation and
replacement with a suitable structural fill material, will be necessary.
Earth Solutions NVV, LLC
Mr. William Hegger
March 7, 2016
ES-4338
Page6
This study has been prepared for the exclusive use of Mr. William Hegger, and his
representatives. No warranty, expressed or implied, is made. This study has been prepared in
a manner consistent with the level of care and skill ordinarily exercised by other members of the
profession currently practicing under similar conditions in this area.
Site Preparation and Earthwork
Site preparation activities will include installing temporary erosion control measures,
demolishing existing shed buildings, establishing grading limits, and performing site stripping
and clearing.
Temporary Erosion Control
The referenced site plan indicates egress will be provided to the residential lots from Aberdeen
Avenue Northeast. Prior to finish grading and paving, temporary construction entrances and
drive lanes, consisting of at least 12 inches of quarry spalls, should be considered in order to
minimize off-site soil tracking and to provide a stable access entrance surface. Geotextile fabric
may also be required underlying the quarry spalls for greater stability of the temporary
construction entrance.
Erosion control measures should consist of silt fencing placed around down-gradient margins of
the site. Soil stockpiles should be covered or otherwise protected to reduce soil erosion.
Temporary approaches for controlling surface water runoff should be established prior to
beginning earthwork activities.
In-situ Soils
From a geotechnical standpoint, native soils encountered at the test pit locations will generally
be suitable for use as structural fill; however the native soils have a moisture sensitivity that can
be characterized as moderate to high. Silty sand soils with fines contents greater than 5
percent typically degrade rapidly when exposed to periods of rainfall. Successful use of native
soils as structural fill will largely be dictated by the moisture content at the time of placement
and compaction. If the on-site soils cannot be successfully compacted, the use of an imported
soil may be necessary.
In our opinion, if grading activities take place during months of heavy rainfall activity, a
contingency should be provided in the project budget for export of soil that cannot be
successfully compacted as structural fill and import of granular structural fill.
Imported Soils
Imported soil intended for use as structural fill should consist of a well-graded granular soil with
a moisture content that is at or slightly above the optimum level. During wet weather
conditions, imported soil intended for use as structural fill should consist of a well-graded
granular soil with a fines content of 5 percent or less defined as the percent passing the
Number 200 sieve, based on the minus three-quarter inch fraction.
Earth Solutions NW, LLC
Mr. William Hegger
March 7, 2016
Rockeries and Modular Block Walls
ES-4338
Page 7
We anticipate rockeries and/or modular block walls of up to six to eight feet in exposed height
will likely be constructed to accommodate the proposed site grading. In our opinion, the use of
rockeries or modular block walls at this site is feasible from a geotechnical standpoint.
Rockeries or modular block walls over four feet in exposed height will require an engineered
design. ESNW can provide engineered rockery and modular block wall designs, upon request.
Subgrade Preparation
Uniform compaction of the foundation and slab subgrade areas will establish a relatively
consistent subgrade condition below the foundation and slab elements. ESNW should observe
the compacted subgrade prior to placing formwork, particularly where existing structures have
been removed.
Structural Fill
Structural fill is defined as compacted soil placed in foundation, slab-on-grade, and roadway
areas. Fill placed to construct permanent slopes and throughout retaining waif and utility trench ·
backfill areas is also considered structural fill. Soils placed in structural areas should be placed
in loose lifts of 12 inches or less and compacted to a relative compaction of 90 percent, based
on the laboratory maximum dry density as determined by the Modified Proctor Method (ASTM
D1557). Soil placed in the upper 12 inches of slab-on-grade, utility trench, and pavement areas
should be compacted to a relative compaction of at least 95 percent. Additionally, more
stringent compaction specifications may be required for utility trench backfill zones, depending
on the responsible utility district or jurisdiction.
Foundations
In our opinion, the proposed building structures can be supported on conventional spread and
continuous footings bearing on recompacted native soil or new structural fill. We recommend
uniformly compacting building slab and footing subgrade areas prior to forming and pouring
concrete to create a uniform support condition. Based on our understanding of the proposed
development, competent native soils suitable for support of foundation should be encountered
at depths of between approximately two to three feet below existing grades. Where loose or
unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the
soils to the specifications of structural fill, or overexcavation and replacement with a suitable
structural fill material, will be necessary.
Provided foundations will be supported as described above, the following parameters can be
used for design:
• Allowable soil bearing capacity
• Passive earth pressure
• Coefficient of friction
2,500 psf
300 pcf (equivalent fluid)
0.40
Earth Solutions NW, LLC
Mr. William Hegger
March 7, 2016
ES-4338
Page 8
A one-third increase in the allowable soil bearing capacity can assumed for short-term wind and
seismic loading conditions. The above passive pressure and friction values include a factor-of-
safety of at least 1.5. With structural loading as expected, total settlement in the range of one
inch and differential settlement of approximately one-half inch is anticipated. The majority of
the settlements should occur during construction as dead loads are applied.
Seismic Design
The 2012 International Building Code recognizes the American Society of Civil Engineers
(ASCE) for seismic site class definitions. Based on the soil conditions observed at the test pit
locations, in accordance with Table 20.3-1 of the ASCE Minimum Design Loads for Buildings
and Other Structures manual, Site Class D should be used for design.
During our subsurface explorations completed on February 11, 2016, groundwater was not
encountered at the test pit locations. In our opinion, site susceptibility to liquefaction can be
characterized as low. The generally consistent densities of the native soils and the lack of a
consistently established groundwater table were the primary bases for this characterization.
Slab-On-Grade Floors
Slab-on-grade floors for proposed residential buildings constructed on the subject site should
be supported on a firm and unyielding subgrade. Where feasible, native soils likely to be
exposed at slab-on-grade subgrade levels can be compacted in situ to the specifications of
structural fill. Unstable or yielding areas of the subgrade should be recompacted or
overexcavated and replaced with suitable structural fill prior to construction of the slab.
A capillary break consisting of a minimum of four inches of free-draining crushed rock or gravel
should be placed below the slab. The free-draining material should have a fines content of 5
percent or Jess (percent passing the Number 200 sieve, based on the minus three-quarter inch
fraction). In areas where slab moisture is undesirable, installation of a vapor barrier below the
slab should be considered. If a vapor barrier is to be utilized, it should be a material specifically
designed for use as a vapor barrier, and should be installed in accordance with the
manufacturer's specifications.
Retaining Walls
Retaining walls should be designed to resist earth pressures and any applicable surcharge
loads. The following values should be used for concrete retaining and foundation wall design:
Earth Solutions t,.M/, LLC
Mr. William Hegger
March 7, 2016
• Active earth pressure (yielding wall)
• At-rest earth pressure (restrained wall)
• Traffic surcharge (passenger vehicles)
• Passive earth pressure
• Allowable soil bearing capacity
• Coefficient of friction
• Lateral seismic surcharge
ES-4338
Page 9
35 pcf (equivalent fluid / granular fill)
50 pcf
70 psf (rectangular distribution)
300 pcf (equivalent fluid)
2,500 psf
0.40
6H (where H equals wall height in feet)
Additional surcharge loading from foundations, sloped backfill, or other loading should be
included in the retaining wall design, where applicable. Drainage should be provided behind
retaining walls such that hydrostatic pressures do not develop. If drainage is not provided,
hydrostatic pressures should be included in the wall design. The geotechnical engineer should
review retaining wall designs to confirm that appropriate earth pressure values have been
incorporated into the design and to provide additional recommendations.
Concrete retaining and foundations walls should be backfilled with free draining material that
extends along the height of the wall, and a distance of at least 18 inches behind the wall. The
upper one foot of the wall backfill can consist of a less permeable (surface seal) soil, if desired.
A perforated drain pipe should be placed along the base of the wall, and connected to an
appropriate discharge location. A typical retaining drainage detail is provided as Plate 3 of this
study.
Drainage
Perched groundwater should be anticipated in site excavations depending on the time of year
grading operations take place, particularly in utility excavations at depth. Temporary measures
to control surface water runoff and groundwater during construction would likely involve
interceptor trenches and sumps. ESNW should be consulted during preliminary grading to
identify areas of seepage and to provide recommendations to reduce the potential for instability
related to seepage effects.
Finish grades must be designed to direct surface drain water away from structures and slopes.
Water must not be allowed to pond adjacent to structures or slopes. In our opinion, foundation
drains should be installed along building perimeter footings. A typical foundation drain detail is
provided on Plate 4.
Earth Solutions NW, LLC
Mr. William Hegger
March 7, 2016
Excavations and Slopes
ES-4338
Page 10
The Federal Occupation Safety and Health Administration (OSHA) and the Washington
Industrial Safety and Health Act (WISHA) provide soil classification in terms of temporary slope
inclinations. Soils that exhibit a high compressive strength are allowed steeper temporary slope
inclinations than are soils that exhibit a lower compressive strength.
Based on the soil conditions encountered at the test pit locations, loose and medium dense
native soils, fill or areas where groundwater seepage is exposed are classified as Type C by
OSHA and WISHA. Temporary slopes over four feet in height in Type C soils must be sloped
no steeper than 1.5H:1V (Horizontal:Vertical). Dense native soils are classified as Type B by
OSHA and WISHA. Temporary slopes over four feet in height in Type B soils must be sloped
no steeper than 1H:1V. Steeper temporary slope excavations can be considered during
construction and should be evaluated by ESNW.
The presence of perched groundwater may cause caving of the temporary slopes due to
excess pore pressure and seepage forces. ESNW should observe site excavations to confirm
soil types and allowable slope inclinations. If the recommended temporary slope inclinations
cannot be achieved, temporary shoring may be necessary to support excavations.
Permanent slopes should maintain a gradient of 2H:1V, or flatter, and should be planted with
vegetation to enhance stability and to minimize erosion. An ESNW representative should
observe temporary and permanent slopes to confirm the slope inclinations are suitable for the
exposed soil conditions, and to provide additional excavation and slope recommendations as
necessary.
Pavement Sections
The performance of site pavements is largely related to the condition of the underlying
subgrade. To ensure adequate pavement performance, the subgrade should be in a firm and
unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in
pavement areas should be compacted to the specifications previously detailed in this report. It
is possible that soft, wet, or otherwise unsuitable subgrade areas may still exist after base
grading activities. Areas containing unsuitable or yielding subgrade conditions will require
remedial measures such as overexcavation and thicker crushed rock or structural fill sections
prior to pavement.
We anticipate new pavement sections will be primarily subjected to passenger vehicle traffic.
For lightly loaded pavement areas subjected primarily to passenger vehicles, the following
preliminary pavement sections can be considered:
• Two inches of hot mix asphalt (HMA) placed over four inches of crushed rock base
(CRB), or;
• Two inches of HMA placed over three inches of asphalt treated base (ATB).
Earth Solutions NW, UC
Mr. William Hegger
March 7, 2016
ES-4338
Page 11
Heavier traffic areas (such as access drives) generally require thicker pavement sections
depending on site usage, pavement life expectancy, and site traffic. For preliminary design
purposes, the following pavement sections for heavy traffic areas can be considered:
• Three inches of HMA placed over six inches of CRB, or:
• Three inches of HMA placed over four and one-half inches of ATB.
The HMA, ATB and CRB materials should conform to WSDOT specifications. All soil base
material should be compacted to at least 95 percent of the maximum dry density. Final
pavement design recommendations can be provided once final traffic loading has been
determined. City of Renton road standards may supersede the recommendations provided in
this report.
Utility Support and Trench Backfill
In our opinion, the native soils will largely be suitable for support of utilities. Organic-rich soil is
not considered suitable for direct support of utilities and may require removal at utility grades if
encountered. Remedial measures may be necessary in some areas in order to provide support
for utilities, such as overexcavation and replacement with structural fill, or placement of
geotextile fabric. Groundwater seepage may be encountered in utility excavations, and caving
of trench walls may occur where groundwater is encountered.
In general, the native soils should be suitable for use as structural backfill in the utility trench
excavations, provided the soil is at or near the optimum moisture content at the time of
placement and compaction. Moisture conditioning of the soils may be necessary at some
locations prior to use as structural fill, especially where groundwater seepage is encountered.
Each section of utility lines must be adequately supported in the bedding material. Utility trench
backfill should be placed and compacted to the specifications of structural fill as previously
detailed in this report, or to the applicable specifications of the City of Renton or other
responsible jurisdiction or agency.
LIMITATIONS
The recommendations and conclusions provided in this geotechnical engineering study are
professional opinions consistent with the level of care and skill that is typical of other members
-in-the profession currently practicing under similar conditions in this area. A warranty is not
expressed or implied. Variations in the soil and groundwater conditions observed at the test pit
locations may exist, and may not become evident until construction. ESNW should reevaluate
the conclusions in this geotechnical engineering study if variations are encountered.
Additional Services
ESNW should have an opportunity to review final project plans with respect to geotechnical
recommendations provided in this report. ESNW should also be retained to provide testing and
consultation services during construction.
Earth Solutions~. LLC
f---,----------··,..---------
Reference:
King County, Washington
Map 626
By The Thomas Guide
Rand McNally
32nd Edition
NORTH
fi
NOTE: This p.rte may contain areas of color. ESNW cannot be
responsi>le for any subsequent misinterpretation of the information
resulting from black & white reproductions of this plate.
Vicinity Map
Aberdeen Avenue N.E.
Renton, Washington
Drwn_ MRS Date 02/23/2016 Proj_ No. 4338
Checked HTW Date Feb. 2016 Plate
I,
i/ /
I /
,/ /r /
5H! I//
I
I
,·re
1 "=40'
\
\
I
I
NORTH
@
80
NOTE: The graph~s shown on this plate are not intended for design
purposes or precise scale measurements, but only to illustrate the
approximate test klcations relative to the approximate locations of
existing and/ or proposed site features. The information illustrated
is largely based on data provided by the client at the time of our
study. ESNW cannot be responsible for subsequent design changes
or intel])retation of the data by others.
NOTE: This plate may contain areas of color. ESNW cannot be
responsi:>le for any subsequent misinterpretation of the information
resulting from black & white reproducbons of this plate.
2ii()
TP-41
\ ·,
\ \ -•-House\ )
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. -------------~-----..::.:.i..._
TP-11 -•-
I
---"l
i
LEGEND
Approximate Location of
ESNW Test Pit, Proj. No.
ES-4338, Feb. 2016
Subject Site
D Existing Building
~
,, .
. J
7
L
/
· h Solutions NWLu
Drwn. MRS
Checked HTW
!cal Engineer mg. Constr union Mun,r,H 1112
, ; and Environmental Science~
Test Pit Location Plan
Aberdeen Avenue N.E.
Renton, Washington
Date 02/23/2016 Proj. No. 4338
Date Feb. 2016 Plate 2
NOTES:
• Free Draining Backfill should consist
of soil having less than 5 percent fines.
Percent passing #4 should be 25 to
75 percent.
• Sheet Drain may be feasible in lieu
of Free Draining Backfill, per ESNW
recommendations.
• Drain Pipe should consist of perforated,
rigid PVC Pipe surrounded with 1"
Drain Rock.
LEGEND:
Free Draining Structural Backfill
1 inch Drain Rock
18" Min. ~1
Structural
Fill
' Perforated Drain Pipe
(Surround In Drain Rock)
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAWING
; Ear\h rlh Solutions NWLLC Solutions . ---
NW ll( , hn1cal Engineering Consu ll( t1n1, Mo11•t0111 g
• and Env11 onme11tal Sc_1ern r ~
'
RETAINING WALL DRAINAGE DETAIL
Aberdeen Avenue N.E.
Renton, Washington
Drwn. MRS Date 02/23/2016 Proj. No. 4338
Checked HTW Date Feb. 2016 Plate 3
Slope
~
..... ' . . . . . . . . -·-·-·-·-·-·
Perforated Rigid Drain Pipe
(Surround with 1" Rock)
NOTES:
• Do NOT tie roof downspouts
to Footing Drain.
• Surface Seal to consist of
12" of less permeable, suitable
soil. Slope away from building.
LEGEND:
Surface Seal; native soil or
other low permeability material.
1" Drain Rock
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAWING
-. /;,
. Ear!h !'Earth Solutions NWLu •Solutmns-----__ NW l l( ~Geotechmal Engmeenng, Co11str uct1011 Mo111101111i:
Drwn. MRS
_ f 2nd Envn onmental Sciences
FOOTING DRAIN DETAIL
Aberdeen Avenue N.E.
Renton, Washington
Date 02/23/2016 Proj. No. 4338
Checked HTW Date Feb. 2016 Plate 4
Appendix A
Subsurface Exploration
ES-4338
The subsurface conditions at the site were explored by excavating a total of four test pits across
the development envelope of the property. The approximate test pit locations are illustrated on
Plate 2 of this report. The test pit logs are provided in this Appendix. The subsurface
exploration was completed in February 2016 using a rubber-tired backhoe and operator
subcontracted by ESNW. The test pits were excavated to a maximum depth of nine and one
haft feet below existing grades.
Logs of the test pits excavated by ESNW are presented in Appendix A. The final logs represent
the interpretations of the field logs and the results of laboratory analyses. The stratification
lines on the logs represent the approximate boundaries between soil types. In actuality, the
transitions may be more gradual.
Earth Solutions flNV, LLC
Earth Solutions NWLLc
SOIL CLASSIFICATION CHART
MAJOR DIVISIONS SYMBOLS TYPICAL
LETIER DESCRIPTIONS
COARSE
GRAINED
SOILS
MORE THAN 50%
OF MATERIAL IS
LARGER.THAN
NO. 200SIEVE
SIZE
FINE
GRAINED
SOILS
MORE THAN 50%
OF MATERIAL IS
SMALLER THAN
NO. 200 SIEVE
SIZE
GRAVEL
AND
GRAVELLY
SOILS
MORE THAN 50%
OF COARSE
FRACTION
RETAINED ON NO.
4SIEVE
SAND
AND
SANDY
SOILS
CLEAN
GRAVELS
(UTILE OR NO FINES)
GRAVELS WITH
FINES
(APPRECIABLE
AMOUNT OF FINES)
CLEAN SANDS
(UTILE OR NO FINES)
SANDS WITH
MORE THAN 50% FINES
OFCOAASE
FRACTION
PASSING ON NO.
4 SIEVE (APPRECIABLE
SILTS
AND
CLAYS
SILTS
AND
CLAYS
AMOUNT OF FINES)
LIQUID LIMIT
LESS THAN SO
LIQUID LIMIT
GR.EATER THAN 50
HIGHLY ORGANIC SOILS
GW
WELL-GRADED GRAVELS, GRAVEL·
SAND MIXTURES, Lml.E OR NO
FINES
POOALY-GAAOEO GRAVELS,
GP GRAVEL· SANO MIXTURES, LITTLE
OR NO FINES
GM SIL'IY GRAVELS, GRAVEL-SANO-
SILT MIXTIJRES
GC CLAYEY~VELS, GRAVEL• SAND•
CLAY MIXTURES
SW WEU.-GRAOED SANDS, GRAVELL V
SANOS, UTTl.E OR NO FINES
SP P00RL Y-ORADED SANOS,
GRAVEU Y SAND, LITTLE OR NO
FINES
SM SILTY SANDS, SANO-SILT
lolXT\JRES
SC CLAYEY SANOS, SANQ. CLAY
!olXTIJAES
INORGANIC SILTS AND VERY FINE
ML SANDS, ROCK FLOUR, Sil TY OR
CLAYEY FINE SANOS OR ClAY=V
SILTS WITTI SLIGHT PLASTICITY
INORGANIC CLAYS OF LOW TO
CL MEDIUM PI.ASTICITY, GAAVELLY
CLAYS, SANDY CLAYS, SILTY
CLAYS, LEAN CLAYS
OL ORGANIC SIL TS AND ORGANIC
SIL TV Ct.AYS OF LOW PLASTICITY
MH
INORGANIC SIL TS, MICACEOUS OR
OL4.TOMACEOUS FINE SANO OR
SILTY SOILS
CH INORGANIC CLAYS OF HIGH
PI.I\STICl'IY
OH ORGANIC CLAYS OF MEOIW TO
HIGH PLASTICITY, ORGANtC SILTS
PT PEAT, HUMUS, SWAMP SOlLS WITH
HIGH ORGANIC CONTENTS
DUAL SYMBOLS are used to indicate borderline soil classifications.
The discussion in the text of this report is necessary for a proper understanding of the nature
of the material presented in the attached logs.
I
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•
Earth Solutions NW
1805 -136th Place N.E., Suite 201
Bellevue, Washington 98005
Telephooo: 425-449-1704
Fax: 425-449-1711
TEST PIT NUMBER TP-1
PAGE 1 OF 1
CLIENT BiU Hepger -·-PROJECT NAME Aberooen AWlnuo N£
l'P:..:R:..:O::J::E::C::T:..:N:..:U::ll=B::E=R:.:_,=4:l38"'============-~--~ _ ___ ~P:..:RO=J:.:E::CT:..:..:L=:OC=Ac.:.11:..:0N=-=R'=e=nto'==n.=W==as=h=ina"'=ton============l
..
f-
-
"
DATE STARTED 2/11/16 COMPLETED __m11rn _ CROUND ELEVATION 287ft TEST PIT SIZE------
EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS:
EXCAVATION METHOD ----------_ _ __ _ AT TIIIE OF EXCAVATION ---------------
AT END Of EXCAVATlON -------------
AFTER EXCAVATION -
LOGGED BY _T~J.,M,__ ____ _ CHECKED BY HlW _
NOTES Oeptl1 of Topsoil & Sod 4": lopson
w 0.
r ~ ffi ~-wm fhE -':I!
0 0.:,
~z
"' n
-
-
-
TESTS
MC=7.30%
Fines= 4.60%
SP
MATERIAL DESCRIPTION
Grayish brown poorly graded SANO with gravel, medium dense, moist
[USDA Classification: very gra\19\ly coarse SAND]
-infiltration test
___§__
-
-.
MC= 10.80%
-old drain field rock
-roots
,____,,..___,,,,e.=s-___ 278.S
Test pd terminated at 8.5 feet below existing grade. No groundwater encountered during
excavation.
Bottom of test ptt at 8.5 feet.
~_ ...... __ ._ _____ _.. _ _._ _ _,_ _____________________________ ~
I
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Earth Solulions NW
1805 -136111 Place N.E.. Sutte 201
Bellevue. Washington geoos
Telephone: 425-44!1-4704
Fax: 425-44!1-471 I
TEST PIT NUMBER TP-2
PAGE 1 OF 1
CLIEtrT Bil!Hegger ............. PROJECTNAME AberoeenAvenueN.E.
PR<>.IECT NUMBER 4338 PRO.,ECT LOCATION Renton. Washington i-:..:===============-" " -··-_c_=======================
'
DATE STARTED ~21~1~1~11-6 ____ COMPLETB) J/11116 ___ . GROUND ELEVATION 294ft TESTPITSIZE ---=-···--
EXCAVATION COtrTRACTOR NW Excavating
EXCAVAllON MEllK>D ------------
LOGGED BY .L!.M __ ... --= CHECKED BY HTW .....
NOTES O..pll1 of Topsoil & SO<l 12": gn,es
ll:' 2 fg >-a: u; 1-W !§ w"' TESTS <.i zr~ "' Cl iz :, C,
0
GROUNO WATER LEVELS:
ATllMEOf' EXCAVATION -=-------=----
AT END Of' EXCAVATION----------------
AFTER EXCAVATION -
MATERIAL DESCRIPTION
MC=29.30%
MC= 16.00% SM I I ,.s Light-brown silty SAND with gravel. medium dense. moist ,__ .......... ==· --~---, 192.S
MC=S.20%
Fines = 0.60%
G,ay poorly graded SANO, medium dense, moist
{USDA Classification: gravelly SANO)
-infiltration test
-' SP
_____ 11,,0 ___ _
-caving
Test pit terminated at 11.0 feet befow: existing grade. No groundwater encountel'8d
duting excavation.
Bottom of test pit at 11.0 feet
283.0
;,____,'-_ _._ _____ .....__,___. __________________________ __,
•
Earth Solutions NW TEST PIT NUMBER TP-3 1805-1361h Place N.E., Sufte 201
Bellevue, Washington 98005 PAGE 1 OF 1
Telephone: 425-449-4704
Fax: 425-449-4711
CLIENT Bi11Heaaer -----· PROJECT NAME Aberdeen Avenue N.E.
PROJECT NUMBER 4338 . PROJECT LOCATION Renton. Washlnglon -----
DATE STARTED 2/11116 COMPLETED ..ll.~~[16 -GROUND ELEVATION 299ft 1EST PIT SIZE
EXCAVATION CONTRACTOR NW Excavating ·-GROUND WATER LEVELS:
EXCAVATION METHOD AT TIME OF EXCAVATION ----------
LOGGED BY TJM __ CHECKED BY J:!l'N ___ ., ______ AT END OF EXCAVATION
NOTES Oecth ofToosoil & Sod 4": gravelllooaoil AFTER EXCAVATION
UJ
0..
t~ ~ffi .; (.J
w"' TESTS 0 :i: 8 MATERIAL DESCRIPTION w-..J:; .; i..J C 0..:, iz :, CJ
0
Grayish brown poorly graded SAND with gravel, medium dense, moist
C .
.. . MC= 3.40%
-
~ SP
-
-.
. MC= 5.70%
L
.._J_g_ 10.0 -caving
289.D MC =8.30% f--
Grayish ·broWn poorly graded SANO, dense,-rTloist
L . SP
MC=4.50% 11.5 [USDA Classification: slightly gravelly SAND] 287.5
Fines = 0. 70% Test pit terminated at 11.5 feet beloweJdsting grade. Nogroundwaterencountered
during exca,.,ation.
Bottom of test pft at 11.5 -·
•
Earth Solutions NW TEST PIT NUMBER TP-4 1805 • 1381h Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005
Telephone: 425-449-4704
Fax: 425-449-4711
CLIENT BillHeg~r PROJECT NAME Aberdeen Avenue N.E.
PROJECT NUMBER 4338 PROJECT LOCATION Renton. Washington
-----
DATE STARTED 2/11/18 COIIIPLETED 2/11/16 GROUND ELEVATION 293 ft TEST PIT SIZE
EXCAVATION CONTRACTOR NW Excavati!!Q ·-GROUND WATER LEVELS:
EXCAVATION METHOD ATTIMEOF EXCAVATION ------------------
LOGGED BY TJM CHECKED BY H,W_ AT END OF EXCAVATION
NOTES ~th ofTQQsoil & Sod 12": grass AFTER EXCAVATION -
IJJ
:,: ~ ffi oi g
:,: " Ii:~ IJJ "' TESTS '-l o..o MA TE RIAL DESCRIPTION w-...J ::; "' ~...J 0 0..::, :i ~z " n
'.:...'.!.'
TPSL :.t. il 1.0 292.0 ----·---
SM
Brown silty SAND with gravel, medium dense, moist
MC=8.10% I MC=5.40% 2.0 291.0 .
Grayish brown poorly graded SANO with silt and gravel, medium dense, moist
. SP-
SM
.
MC=5.50% 45 288.5
_§_ Fines = 2.50% •()" Gray poorly graded GRAVEL with sand, dense, moist
Do D( [USDA Classification: extremely gravelly coarse SAND]
. ,o (
o(Joi
GP " D
pO(
·Cl· Do D'
. oc
·Cl·
. MC=S.10%
D0 D, 9.0 ·-284.0
Test pit terminated at 9.0 feet betow existing grade. No groundwater encountered during
excavation.
Bottom of test pit at 9.0 feet.
Appendix B
Laboratory Test Results
ES-4338
Earth Solutions WI, LLC
• Earth Solutions NW GRAIN SIZE DISTRIBUTION
1805 -136th Place N. E .. Suite 201
Bellevue, WA 98005
Telephone: 425-284-3300
CLIENT 2525 Aberdeen LLC
PROJECT NUMBER ES-4338
PROJECT NAME 2525 Aberdeen Ave NE
PROJECT LOCATION Renton
100 ! I
95 i i
I !I
90 !
-
U.S SIEVE OPENING IN INCHES U.S SIEVE; NUMBERS HYDROMETER
6 4 3 2 15 1 'W 1/2~ 3 4 6 8101416 20 30 40 5060 100140200
: I -,, ~--f'[ : 1., I I ,:: Ii I ,: I
I I I l •! \', i . ~ • • , : j i i '
' ', 1, • 1.:_, -· --•---~ --+~-+1-'-'-. -11,---+,,Hl1_+,I ++-1,-+-f--,f--':f-->-~l --l
·:'' i , .al '1, 1 i I , , 1
-----~-~-+--+---+++++---+--+--,-.+-+-,----1
' : • I : I' " I. ' I 'I,: ! 1' I '
1, I I i I : -s_~ ~,. ' I I ! 1' ' ,I
r i , \ / 1 • I I I j : B5H,-+-t-, --,-, -,,-,,-,,---ti,---~l;;-,-,-'--~"-c%--H,,,.++-,+-+-+--+1-+-:, --+,++i-+-t--+l---1--f"'I, -+--+--!,~----t
Bo ...... -+----.. ',1..,1 .... : .... : ___ ~·--+:-:~-------I ii ' I ' : '
! r r ;1111 ::~ · ~:.:: ; 1 : 1
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75 ! ; I : ii ! '· : : i\ ~t I I : i i I : I I : !
701-1-+I-J-· --+.,, 1·H:-'-',-+--+----,-p+1-1-.-----~ --W' l"al-+1,-,-+-+I,-+' --++1-1+-+-I +---+--'--+-~-a!-+-t---1
65 i I Ii I' : I: I I I i I
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so I i . , : ; i L. ---------~·-'-+-;' -+~--...++++---+'-+--+--'~--1-,' -+--+--1
! I 'I ! I ' ' : I ! I ' i
55>-+-----+1-+-+-+------+--H-------~ -----+-..-.-+--+---'Tl+++-+--+---+-+--+-+-+---1
I ' I ; i ' ! : ; -,: : i I i ' ' I ' ' I i 5ot-t~-,___---'-+,-+-'--~--1-t--l'c-------._,,___~-+-++----1t-----+-++-+-+-+--i---+---+~--+--+--+---1
I i 11' 11, I'' I , , , , ! , ,
: --i : i I I 451-'-, -+-.--+'-'"-+'-+-'1-+------H--,--'---t----·-------+-+-t+-t-+----+H-i-t-f----+---l-f---f----+----'"-+-<---1
ii Iii 1: I " ' ,1 : 11 ! I I, I ,1
401-+'-+-t----'-'H l,-+l-+--+----+--1-t-'-'-'---~·-''"-· +-liH--+--+--'-,, ,__· >-+-+-+---+---+++~-+-+--+---t
351-+-+-11_,__+1
...,
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!__,i ... l...,i __ --+! __ ,..,1·:,_i. ---~-"--~--~ l·I !! i i 1
i ... I I I
!, I i ' ,' I' I! '., 11 ] .L :, :,1' II', II ' r Iii i
30t-+--+-t--'-+H-H-+---+---f-t'' 1,.....1 _______ ~\,-c-~-+-+tt--+--+' --+' !-!'-+'+--+-+-'' -+---lf'+t-' ,...:,_ :i +-+---J'---1
J i I \!II ! II 1
\~":, , , ii. i ! 1 'I:: I I I
2205 t--+ ;: -+--!-!, --+ ,'H-+ 11..,1_+-'-+' __ : .... ·-+: ~: --------1,i::1..,._ ~-++-ft-+-+--+]+ ,1+-'1 ii++-,-1-+--lf----+-.-'-i +:+-,i+ ,i-J'-+-t--
, I I I ' ·, I ! . '
11 1 i I I : I I I I ! : ! I
15 t-+-+,, -.--+,+-' ;,-+-+,-.-+-; --+-->->, --++ ----------~ I\ I\ ' i i j'
'I I I i : : I ' I \ ii 10 '! ,. I 11 ' • I . ----' ' '
5 J_.___I -1----H-! lt-i ,' H!--+-<'-,-~i----t,1 :~,+--' _ _ _ _ , , mi • : i i 'i 'r! i (l"I \ \..-~ I I I I I j " '1 i '--I 0 ' 11 I;!' ! -! I
100 10 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS .---------------------------------------------
COBBLES GRAVEL SAND SILT OR CLAY co-;-s-e---··· medium I fine coarse fine
----------------------------------~ Specimen Identification Classification Cc Cu
:..-•-+-_T_P_·1 ____ 3_.0_0_fl _____ U_S_D_A_:_G_ray_V_e_ry Grav_e_ll_y_C_o_a_rs_e_Sa_n_d ___ U_S_C_S_:_S_P_w,_·t_h_G_ra_v_e_l. _______ _
"' ii: TP-2 2.00ft _ USDA: Gray Gravelly Sand. USCS: SP.
; • TP-3 11.50ft USDA: Grayish Brown Slightly Gravelly Sand. USCS: SP.
0.32 20.04
0.79 2.58
0.83 2.48
i..-* __ T_P_-4 ____ 4_.S_O_fl~~--U_S_D_A_:_G_ra~y Extremely Gravelly Coarse Sand. USCS: GP with Sand. 0.75 27.97
~1------------------~ Specimen Identification D100 D60 D30 D10 LL PL Pl %Silt %Clay
;I; •. TP-1 3_0ft 19 3.677 0.467 0-183 4.6 wt-.,-----------------
~%' TP-2 2_0ft 19 .,,___ _________________ _ 0.681 0.378 0-264 0_6
~~----~--
:;: • TP-3 11.5ft. 9_5 e,1------------------
~ * TP-4 4.5fl 37.5 --------------------
ffi ~----------------------------------------------
0.662 0.382 0-266 0.7 -------
9.544 1.562 j 0.341 2.5
EMAIL ONLY
EMAIL ONLY
Report Distribution
ES-4338
Mr. William Hegger
13110 Northeast 17t" Place, #203
Woodinville, Washington 98072
Encompass Engineering & Surveying
165 Northeast Juniper Street, Suite 201
Issaquah, Washington 98027
Attention: Mr. Barry Constant
Earth Solutions NW, LLC
APPENDIX B
ARBORIST REPORT
AFM
.\nu . ..-ican Forest ;\lanagl"llll'llt
11415 ~'E 128th St Suite 110 Khkla11d \\':\ 98034 • (+25)820-3420 • FAX (425)820-3+3i
Vl'>Yw .americanfores tm anagement.com
Arborist Report
2525 Aberdeen Ave NE
Renton, WA
January 27th, 2016
Table of Contents
1. Introduction .............................................................................................................. 1
2. Description ............................................................................................................... 1
3. Methodology ............................................................................................................ 1
4. Observations ........................................................................................................... 2
5. Discussion .... ........ ..... ........ ..... . .................................................................. 2
6. Tree Retention...................... . ........................................................................ 3
7. Tree Replacement...................... . ............................... 3
8. Tree Protection Measures...... . .................................................... .4
Appendix
Site/Tree Photos -pages 5 -11
Tree Summary Table -attached
Tree Plan Map -attached
American Forest Management 1/27/2016
2525 Aberdeen Ave NE Arborist Report
1. Introduction
American Forest Management, Inc. was contacted by Rill Hegger, and was asked to compile an 'Arborist
Report' for two parcels located within the City of Renton.
The proposed 4-Lot short plat encompasses the property at 2525 Aberdeen Ave NE. Our assignment is to
prepare a written report on present tree conditions, which is to be filed with the preliminary pennit application.
This report encompasses all of the criteria set forth Lmdcr City of Renton code section 4-4-130. The tree
retention requirement is 30% of significant trees.
Date of Field Examination: January 25'", 2016
2. Description
54 significant trees were identified and asscsscd on the property. These are comprised of a mix of native species
and planted ornamental species. According to City of Renton code, a significant tree is a "tree ,vith a caliper of
at least six inches (6"), or an alder or cottomvood tree with a caliper of at least eight inches (8"). Trees qualified
as dangerous shall not be considered significant. Trees planted within the most recent ten (10) years shall
qualify as significant trees, regardless of the actual caliper."
A numbered aluminwn tag was placed on the lower trunks of the subject trees by the surveying crew. These
numbers were used for this assessment. Tree tag numbers correspond with the numbers on the Tree Sununary
Tables and copy of the attached site swvev.
There is one neighboring tree with a drip line that extends over the property line.
3. Methodology
Each tree in this report was visited. Tree diameters were measured by tape. The tree heights ·\vere measured
using a Spiegel Relaskop. Each tree was visually examined for defects and vigor. The tree assessment
procedure involves the examination of many factors:
• The crown of the tree is examined for current vigor. This is comprised of inspecting the crown
(foliage, buds and branches) for color, densil\, form, and annual shoot growth. limb dieback and
disease. The percentage of live crown is estimated for coniferous species only and scored
appropriately,
• The bole or main stem of the tree is inspected for decay, which includes cavities, wounds, fruiting
bodies of decay (conks or mushrooms), seams, insects, bleeding, callus development, broken or dead
tops, structural defects and unnatural leans. Structural defects include crooks, forks with V -shaped
crotches, multiple attachments, and excessi\-e sweep.
• The root collar and roots are inspected for the presence of decay, insects and/or damage, as well as if
they have been injured, undermined or exposed, or original grade has been altered.
Based on these factors a detennination of \·iability is made. Trees considered "non-viable' are trees that are in
poor condition due to disease, extensive decay and/or cumulative structural defects, which exacerbate failure
potential. A "viable' tree is a tree found to be in good health, in a sound condition with minimal defects and is
suitable for its location. Also, it will be wind firm if isolated or left as part of a grouping or grove of trees. A
'borderline' viable tree is a tree where its "·iability is in question. These are trees that are beginning to display
symptoms of decline due to age and or species related problems. Borderline trees are not expected to positively
contribute to the landscape for the long-term and art:: not recommended for retention.
The attached site plan/tree map indicates the Yiability of the subject trees.
Page 1 American Forest Management 1/27/2016
2525 Aberdeen Ave NE Arborist Report
4. Observations
The subject trees are comprised of a mix of nati\·e and planted species. The native tree species are primarily in
the access easement and in Lot 1. Specific tree information can be found on the attached tree table.
Douglas·fir trees
The Douglas-fir trees vary in age and condition. Some of the common detects include broken tops, crooked
trunks and small live crowns. The Douglas.fir trees in Lot 1 are growing very closely together, a few have poor
trunk taper and small CIO\\TIS as a result of this. Additionally, many of the trees exhibit signs of suppression.
Big leaf maple trees
The big leaf maple trees on the property are in fair to poor condition. Structural defects such as co.dominant
stems with poor attachment, crooks in the trunk and leaning tnmks were common. Decay was also observed in a
few of the maple trees.
Pacific mad.Tone trees
The pacific madrone trees on the property arc generall::,.-· in decline. Concerning defects observed included stem
cankers and branch dieback. The pacific madrone trees range from fair to fair-poor condition.
Western red cedar trees
The western red cedars on the property are young and have good "igor. The two western red cedars are both in
good condition and are viable.
Other concerning trees
Tree# 115 is a European white birch planted in the center of the property. This tree has an over exposed root
flare. This ti;ee additionally has significant trunk decay. This tree is in poor condition and is non-viable.
Tree # 117 is a flowering cherry tree planted in the center of the property. This tree has a co-dominant stem that
forks 5' from the base of the trunk The attachment hetween the two main stems is a weak, v shaped attachment
and there is decay at the area of attachment. This tree is in poor condition and is non.viable.
Tree# l l 8 is a grand fir on the south edge of the property. This tree has moderate die back in over 30% of the
crovm. No concerning defects were obserYed on the trunk of the tree. This tree is in decline and is in fair to poor
condition. The subject tree is borderline viable.
Tree # 122 is a cherry plum in the center of the property. This tree has a large, visible, column of decay in 8 feet
of the lower trunk. This tree is in poor condition and is non-viable.
Neighboring Trees
Tree #20 l is a young lodge pole pine north or the property line. This tree has a full crown and good taper. No
concerning defects were observed.
5. Discussion
The grade in most of Lot l will be lowered hY a few feet to match the grade of the rest of the property. Grade
changes should not occur within the limits of disturbance for trees that will be retained. Lowering the grade near
trees removes and damages roots, which reduces the ability of the tree to absorb water and nutrients and
maintain vigor. Grade changes can also reduce the structural integrity of trees.
Finished landscaping work within the drip-lines of retained trees shall maintain existing grades and not disturb
fine root mass at the grotmd surface. Finish landscape 1,,vith beauty bark or new lawn on top of existing grade.
Add no more than 2" to 4" of mulch/beauty bark or 2'' of composted soil to establish new lawn.
The extent of drip-lines (farthest reaching branches) for the subject trees can be found on the tree summary
tables at the back ofthis report. These have also been delineated on a copy of the site survey for viable/healthy
trees proposed for retention. The infonnation plotted on the attached survey plan may need to be transferred to
Page 2 American Forest Management 1/2712016
2525 Aberdeen Ave NE Arborist Report
a final tree retention/protection plan to meet City submittal requirements. The trees that are to be removed shall
be shown "X'd" out on the final plan.
The Limits of Disturbance (LOD) measurements can also be found on the tree swnmary table. This is the
recommended distance of the closest impact (soil excavation) to the trunk face. These should be refen .. -nced
when determining tree retention feasibilit). The LOD measurements are based on species, age, condition, drip-
line, prior improvements, proposed impacts and the anticipated cmnulative impacts to the entire root zone.
Tree Protection fencing shall be located be:vond the drip-line edge of retained trees, and only moved back to the
LOD when work is authorized.
There are no major conflicts concerning neighboring trees. Tree #201 is on the north perimeter and with tree
protection fencing, no major root damage is expected.
6. Tree Retention
A total of 54 significant trees were identified on the subject property. Five of the significant trees are in poor
condition and three are in fair-poor condition. These eight borderline to non-viable trees were not included in
the tree calculation.
Land.mark trees and tree groves \Vere prioritized when selecting trees for retention, per the City of Renton tree
code 4-4-130.
Tree Calculation based on 46, healthy, viable, significant trees
Viable Trees proposed for removal -28 ( 61 % )
Viable Trees proposed for retention -18 t39%)
Tree Type Removal Retained
Landmark# 2 3
Landmark% 40% 60%
Significant# 26 15
Significant % 63% 37%
Total# 28 18
Total% 61% 39%
7. Tree Replacement
Total
5
11%
41
89%
46
100%
Replacements trees may be required. Consult your city planner for tree replacement requirements. All
replacement trees are to be planted on site. For planting and maintenance specifications, refer to Section 4--4-
130 of the Renton Tree Ordinances.
Page 3 American Forest Management 1/27/2016
2525 Aberdeen Ave NE Arborist Report
8. Tree Protection Measures
The following guidelines are recommended to ensure that the designated space set aside for the preserved trees
are protected and construction impacts are kept to a minimum.
• Tree protection barriers shall be initially· erected at 5' outside of the drip-line prior to moving any
heavy equipment on site.
• Tree protection fencing shall only he moved where necessary to install improvements, but only as
close as the Limits of Disturbance. as indicated on the attached plan.
• Excavation limits should be laid out in paint on the grolUld to avoid over excavating.
• Excavations within the drip-lines shall be monitored by a qualified tree professional so necessary
precautions can be taken to decrease impacts to tree parts. A qualified tree professional shall monitor
excavations when work is required and allowed up to the ''Limits of Disturbance".
• To establish sub grade for foundations, curbs and pavement sections near the trees, soil should be
removed parallel to the roots and not at 90 degree angles to avoid breaking and tearing roots that lead
back to the trunk within the drip-line. Am roots damaged during these excavations should be exposed
to sound tissue and cut cleanly "'1th a saw Cutting tools should be sterilized with alcohol.
• Areas excavated within the drip-line of retained trees should be thoroughly irrigated weekly during dry
periods.
• Preparations for final landscaping shall be accomplished by hand within the drip-lines of retained trees.
Plantings v,rithin the drip lines shall he limited. Large equipment shall be kept outside of the tree
protection zones.
There is no warranty suggested for any of the trees subject to this report. Weather, latent tree conditions, and
future man-caused activities could cause physiologic changes and deteriorating tree condition. Over hme,
deteriorating tree conditions may appear and there may be conditions, which are not now visible which, could
cause tree failure. This report or the verbal comments made at the site in no way warrant the structural stability
or long tenn condition of any tree, but represent my opinion based on the observations made.
Nearly alf trees in any condition standing within reach of improvements or human use areas represent hazards
that could lead to damage or injury.
Please call if you have any questions or I can be of further assistance.
Sincerely,
Kelly Wilkinson
ISA Certified Arborist #PN-7673A
ISA Tree Risk Assessment Qualified
Page 4 American Forest Management 1/27/2016
2525 Aberdeen Ave NE Arborist Rep ort
Photos
Pag e 5 American Forest Management 1/27/2016
2525 Aberdeen Ave NE Arborist Report
Page6 American Fore st Management 1/27/2016
2525 Aberdeen Ave NE Arborist Report
Page 7 American Fo rest Management 112712016
2525 Aberdeen Ave NE Arborist Report
View of Lot 1 from the east
J J ·. l ~.
Page 8 American Forest Management 1/27/2016
2525 Abe rd een Ave NE Arborist Report
Tree #120 -black oak
Page 9 American Forest Management 1/27/2016
2525 Aberdeen Ave NE Arborist Report
South end of Lot 1
Page 10 American Forest Management 1/27/2016
2525 Aberdeen Ave NE Arb orist Report
Tree #14_6 -paci!ic madrone with Nattrassia canker
Page 11 American Forest Management 1/27/2016
Tree/
Ta~ecies
101 n.-.. .... Jas-fir
102 Douglas-fir
103 Douglas-fir
104 western red cedar
105 Douglas-fir
106 bia leaf maple
107 lodaennle oine
108 western red cedar
109 Douglas-fir
110 pacific madrone
111 pacific madrone
112 Douglas-fir
113 Douglas-fir
114 Douglas-fir
115 European white birch
116 honey locust
117 flowering cherry
118 rand fir
119 aianl ..,......uoia
120 black oak
121 honey locust
122 cherry plum
123 Douglas-fir
124 bia leaf maNF!
125 Douglas-fir
126 big leaf maple
127 big leaf maple
128 Doualas-fir
Tree Summarl_ Table
For: 2525 Aberdeen Ave NE
City of Renton
DBH Height
(inches) (feet) Drip-Line/Limits of Disturbance (feet)
N S E W
31 90 11 16 11 22
23 65 8 12 18 10
6 22 6 5 6 5
6 22 6 5 6 5
36 107 18 20 22
12, 20 61 9 9 12
8 36 8 9 8 11
6 28 6 8 10
17 63 11 11 12
21 46 14 9 22
13 52 2
6 26 8 9 10
17 87 13 8 12
16 91 14 14 8
9 35 11 6 10 12
10 39 8 18 12 8
16 37 14 16 12 12
41 104 18 21 18
11, 11 46 8 6 10
25 76 25 21 27
9 29 0
20 27
24 96 11 12
8 34 20 0 0 24
14 59 13 5 8 5
11 58 7 3 16 12
12, 6, 14 61 18 16 6 17
17 88 9 11 18
Drip-Line and Limits of Disturbance measurements from face of trunk
American Forest Management, Inc.
Date: 1/25/2015
Inspector: Wilkinson
Condition Viabili.!z:.
fair viable
fair viable
good viable
aood viable
good viable
=, non-viable
fair viable
fair viable
fair viable
fair viable
fair viable
fair viable
fair viable
fair viable
pooc non-viable
fair viable -, non-viable
fair-poor borderline
fair viable
fair viable
fair viable
pooc non-viable
aood viable
fair viable
fair viable
fair viable
fair viable
fair viable
Comments
broken too, landmark
crooked lrunk
landmark
one stem dead, the olher declining
dieback
decay, 10% dieback, forks al 5'
20% dieback
exposedroolflare,decay
exl'Y'lsed root flare
severe decay
severe dieback
forks al 1'
leans S
severe decav
crooked, leans NW
crook at 7'
forks al 2', poor attachment
Trees on neighboring properties -Drip-line and Limits of Disturbance measurements from property lines
Pro.e_osal
relaln
relaln
relain
remove
cemove
rnmove
remove
remove
cemove
remove
remove
remove
remove
remove
remove
remove
remove
,emove
relain
relain
relain
remove
relain
relaln
remove
cemove
remove
cemove
Tree/
Ta~ecies
129 Oouc las-fir
130 Douglas-fir
131 Douglas-fir
132 Oouc: las-fir
133 Douglas-fir
134 Oouc las-fir
135 Douglas-fir
136 Douglas-fir
137 Douglas-fir
138 Douglas-fir
139 Douglas-fir
140 Lombardy poplar
141 Douglas-fir
142 big leaf maple
143 Douglas-fir
144 Douglas-fir
145 OoU< las-fir
146 pacific madrone
147 Lombardy ...... pier
148 Lombardy poplar
149 Douglas-fir
150 Doualas-fir
151 Oouolas-fir
152 Douglas-fir
153 western larch
154 Lombardy poplar
201llodgel'V'lle pine I
Tree Summary Table
For: 2525 Aberdeen Ave NE
City of Renton
DBH Height
(inches) (feet) Drip-Line/Limits of Disturbance (feet)
i'f E W N
12 84 8 5 8
12 85 5 5 17
15 86 9 15
10 41 8 12
12 88 8 9
6 31 8 3 2 10
14 90 10 7 3
6 42 3 4 12 2
16 92 6 5 15
10 51 7 6 2 8
10 76 3 7 4 3
16 90 6 6 5 7
7 68 7 6 4 4
7 47 8 6 9 3
8 62 8 0 15
20 95 7 13 11 14
9 51 2 10 7 4
13 48
10 58 2 4 4
9 62 3 4 4
8 30 8 7 11 2
17 95 10 11 15 12
12 60 4 16 10
11 58 7 17
6 32 7 8 6
37 101 6 7 7
Neiahborina Tree
9 I 32 I I 6 I I
Drip-Line and Limits of Disturbance measurements from face of trunk
I
American Forest Management, Inc.
Date: 1/25/2015
Inspector: Wilkinson
Condition Viability
raic viable
fair viable
rair viable
fair viable
fair viable
fair viable
fair viable
fair viable
fair viable
poor non-viable
fair viable
fair viable
fair viable
fair viable
fair viable
fair viable
fair viable
fair-poor borderline
rair viable
rair viable
fair-poor borderline
fair viable
fair viable
fair viable
"""" viable
fair viable
aood I viable
Comments
suooressed
sunnressed
broken top, 30% live crown
suppressed
decau, 50% die back
broken top, small live crown
10 dAn lean E
landmark
I
Trees on neighboring properties -Drip-line and Limits of Disturbance measurements from property lines
Proeosal
remove
remove
remove
remove
remove
remove
'""'°"" remove
remove
remove
remove
remove
remove
remove
relain
relain
relain
remove
retain
retain
,emove
retain
relain
relain
relain
relain
I
••
. ., ....
~ .•·
' ' \'I 0 ~
I
1. I
APPENDIX C
KCRTS ANALYSIS
Stormwater Design
Per Geotechnical Engineering Study conducted for this project by Earth Solutions NW, March 7,
2016, the underlying soil is poorly graded sand with gravel and is very suitable for infiltrating
stormwater. Per their recommendations, a design infiltration rate of 20 inch/hr should be used (this
includes a factor of safety of greater than 10, a very conservative design rate).
Small Infiltration Basins will be used to infiltrate stormwater the future homes on the lots and for
the private shared driveway, as outlined in section 5.4.7 of the 2009 King County Surface Water
Design Manual (KCSWDM).
Each lot will have a maximum of a bout 3,000 sq-ft of impervious surface. The shared driveway will
have about 3,000 sq-ft of paving. KCRTS was used to design 100-year infiltration for a 3,000 sq-ft
impervious area, to conceptually size infiltration for each of the three new lots and the shared
driveway.
KCRTS Input:
Regional Scale Factor per 2009 KCSWDM fig 3.2.2.A
Developed Conditions Impervious Area
Developed Conditions Pervious Area
Using KCRTS:
Developed Conditions Flows (3,000 sq-ft impervious)
Flow Frequency Analysis
Time Series File:15615d.tsf
Project Location:Sea-Tac
ST 1.0
3,000 sq-ft= 0.07 acres
0
---Annual Peak Flow Rates--------Flow Frequency Analysis-------
Flow Rate Rank Time of Peak --Peaks Rank Return Prob
(CFS) (CFS) Period
0.017 6 2/09/01 2:00 0.033 1 100.00 0.990
0.015 8 1/05/02 16:00 0. 026 2 25.00 0. 960
0. 020 3 12/08/02 18:00 0.020 3 10.00 0.900
0.017 7 8/26/04 2:00 0.020 4 5.00 0. 800
0.020 4 10/28/04 16:00 0.018 5 3.00 0.667
0.018 5 1/18/06 16:00 0. 017 6 2.00 0.500
0. 026 2 10/26/06 0:00 o. 017 7 1. 30 0.231
0.033 1 1/09/08 6:00 0.015 8 1.10 0.091
Computed Peaks 0.031 50.00 0.980
The infiltration basins were sized for the 100 year storm.
lOOyr
25yr
lOyr
2yr
SOyr
Infiltration Basin Design
KCRTSlnput:
Developed Conditions Flows from above (3,000 sq-ft impervious)
infiltration rate of 20 in/hr=> 3 min/inch (equivalent design infiltration rate)
(2) Infiltration Basins per lot (or joint driveway) See diagram below
(2) 5' X 5' bottom infiltration areas
(2) 3' deep X 4' diameter precast CB's w/o bottom
2.5' of washed gravel below open part of CB's
20"x 24 .. standard
catch basin lid
6" PVC eloow short bend
inlet 1--~'1
oil collection -+I---'
30'
sediment collection -++-.,, "
I
catcti basin with bottom
?
X-SECTION
NTS
Infiltration Basin Routing File for KCRTS
Stage Discharge Storage Perm-Area
(Ft) (CFS) (Cu-Ft) (Sq-Ft)
0.00 0.000 0. 0.
1.00 0.000 17.5 50
2.00 0.000 35 50
3.00 0.000 56.3 50
4.00 0.000 81.4 50
5.00 0.000 106.5 50
6.00 0.000 131.6 50
7.00 0.000 156.7 50
8.00 0.000 181.8 50
0.00 Ft : Base Reservoir Elevation
3.0 Minutes/Inch: Average Perm-Rate
24' dia catch basin lid
NOTE: fill excavation
with orain rock
filter fabric
48" precast catch
basin wlo botlom
1 1 /2" to 3" washed
drain rock
5' X 5' bottom Infiltration
area
Using KCRTS to route developed flows though above defined double infiltration basins:
Flow Frequency Analysis
Time Series File:basin3000x2-5x5.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--------Flow Frequency Analysis-------
Flow Rate Rank Time of Peak --Peaks --Rank Return Prob
(CFS) (CFS) (ft) Period
0.000 6 2/09/01 3:00 0.000 5.34 1 100.00 0.990 lOOyr
0.000 8 1/05/02 17: 00 0.000 1. 05 2 25.00 0. 960
0.000 4 2/27/03 8:00 0.000 0.86 3 10.00 0.900
0.000 7 8/26/04 3:00 0.000 0.83 4 5.00 0. 800
0.000 3 10/28/04 17: 00 0.000 0.73 5 3.00 0.667
0.000 5 1/18/06 14:00 0.000 0. 71 6 2.00 0.500
0.000 2 10/26/06 1:00 0.000 0.59 7 1.30 0.231
0.000 1 1/09/08 10:00 0.000 0.51 8 1.10 0. 091
Computed Peaks 0.000 3. 91 50.00 0.980
¢ Double infiltration basins will fill up to a depth of 2.84 1 in a 100
year stoi:m.