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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
Storm Water Drainage Assessment Report
Project Name: FYCD Cultural & Education Associates
Project Address: 711 Monroe Ave N.E.
Renton, Washington
Parcel Numbers: 7809200075
Developer:
Engineer: Ali Amirzehni P.E.
Company: Consultant Engineer
Address: 3952 112th Ave N.E., Bellevue, WA 98004
Phone Number: (206) 288-3122
Revised Report Date: May 25, 2018
_______________________________
Engineer Stamp:
Ali Amirzehni P.E., Consultant Engineer
Zce.engineering@gmail.com, 206-288-3122
PRELIMINARY SUBMITTAL
Technical Information Report
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
Table of Contents
Section 1: Project Overview
Section 2: Conditions and Requirements Summary
Section 3: Offsite Analysis
Section 4: Flow Control, Low Impact Development (LID) and Water Quality Facility Analysis and Design
Section 5: Conveyance System Analysis and Design
Section 6: Special Reports and Studies
Section 7: Other Permits
Section 8: CSWPP Plan Analysis and Design
Appendix
Soil Report
Drainage Site Plan
Construction Stormwater Pollution Prevention Plan
Maintenance Requirements
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
Google Photo of the site
Vicinity Map
Technical Information Report
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
Section 1: Project Overview
The site is located at 711 Monroe Avenue NE in Renton Washington. The site consists of a single lot with
total area of about 13,532 square feet (0.31 acres). The western portion of the site is currently
developed with a single-family residence. A driveway extends through the north portion of the property
from the east and Monroe Ave NE. The reminder of the property is vegetated with grasses, shrubs,
bushes, and trees. This project is proposing to demolish the existing single family residence and
construct a new structure within the existing structure foot-print. The new structure will be converted
to I Kuan Tao Cultural Center. Surface parking spaces will be provided within the front yard. Access to
the site would be maintained off of Monroe Avenue NE.
The site gently slopes downward toward the southwest and west with topographic relief of less than 8
feet. There is a moderate steep slope extending downward to the west in the area just west of the
property. This area is well vegetated with low lying brushes and trees. The slope is up to 15’ height and
has magnitudes of 30 percent.
The site underlain by glacial till soil which typically has a very low permeability. The factored infiltration
rate is 0.28 inches /hour according to the attached soil report prepared by COBALT Geoscience.
This project proposes 4,674 sf of new plus replaced impervious surface, and Table 1 & 2 summarizes the
impervious area calculation.
Table 1. Summary of existing site conditions
Table 2. Summary of proposed site conditions
Surface Type Area Units Notes
Roof (with eaves) 1,938 s.f.
New Driveway 2,736 s.f.
Existing Parking Area 1,962 s.f. To remain
Total New & Replaced
Imp Area *
4,674 s.f.
Landscaped Area 8,878 s.f.
Total Lot 13,552 s.f.
Surface Type Area Units Notes
Roof (with eaves) 1,720 s.f.
Driveway & walkway 5,020 s.f.
s
Total Imp Area 6,740 sf
Landscaped area 6,812 s.f.
Total Lot 13,552 S.f.
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
Section 2: Conditions and Requirements Summary
This project proposes 4,674 sf of new plus replaced impervious surface and qualifies for simplified
Drainage Review as described in City Of Renton Surface Water Design Manual .
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
Core Requirements per 2017 City of Renton Surface Water Design Manual.
Core Requirements #1- Discharge at the Natural Location: The project will discharge to the natural
downstream location. Downstream drainage patterns will not be altered.
Core Requirement # 2-Offsite Analysis: This project is proposing less than 5000 sf of new impervious
area and exempt from offsite analysis.
Core Requirement # 3 – Flow Control Facility: This project is proposing less than 5,000 sf of new
impervious area and exempt from flow control facility.
Core Requirement # 4 – Conveyance system: This project is not proposing to construct or modify any
conveyance system.
Core Requirement # 5 – Maintenance & Operation: Will be provided.
Core Requirement # 6 – Erosion and Sediment Control: Drainage Plan and Construction Stormwater
Pollution prevention (CSWPP) Plan will be provided. See section 8
Core Requirement # 7 – Financial Guarantees & Liability: A financial guarantee will be provided by the
owner upon requested.
Core Requirement #8- Water Quality: The project proposes less than 5,000 sf of new plus replaced PGIS
and exempt from these requirements.
Core Requirement #9- On Site BMP: The requirement for mitigation of target impervious surface is
discussed in Section 4.
Section 3: Offsite Analysis
N/A
Section 4: Flow Control, Low Impact Development (LID) and Water Quality Analysis
Stormwater on-site BMps elements are designed in-accordance to the 2017 City of Renton Surface
Water Management Design Manual.
The project qualifies for Simplified Drainage Review, small lot BMP requirements as described in
section 1.2.9.2.1.
To address the requirements for mitigation of target impervious surface, implementing of full infiltration
and limited infiltration BMP’s were considered.
Implementation of full and limited infiltration is not feasible due to soil type and shallow ground water
table. The site is underlain by glacial till which typically has a very low permeability. The factored
infiltration rate was measured to be 0.28 inches/hour. Infiltration rate less than 0.30 inches /hour is
considered to infeasible. Soil mottling was also observed from 2 to 5’ below existing grade.
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
Rain garden BMP was also considered. Implementation of Rain garden is also not feasible due to soil
type, land availability, conflict with utilities, and set back requirements.
Permeable Pavement BMP per Appendix C, Section C2.7 was selected to meet the FCBMP requirements
for the new driveway and walkway area. The existing driveway drainage will not be altered and will
continue to sheet flow and dissipate into the surrounding landscaped area. New parking area is 2,736 sf,
see the attached drainage site plan.
Perforated pipe connection BMP was selected for the roof runoff. All the downspouts will be tight lined
and connected to the perforated pipe connection structure. The total new roof area is 1,938 sg, and 10’
of trench with perforated pipe will be provided with a connection to the City drainage system on
Monroe Ave NE.
All new pervious area will receive soil amendment per the City Of Renton standard plan.
Section 5: Conveyance System Analysis and Design
N/A
Section 6: Special Report and Studies
N/A
Section 7: Other Permits
N/A
Section 8: CSWPP Plan Analysis and Design
The temporary erosion control plan is designed and attached to the appendix.
The contractor shall implement the following measures:
1. Mark Clearing limits / Minimize Clearing.
2. Minimize Sediment Tracked Offsite: Construct a construction entrance per City Of Renton
Standard plan. Existing driveway can be substitute.
3. Control Sediment. Install Silt fence and wattles as needed to control sediment.
4. Stabilize Exposed Soils: Cover exposed soil per City Of Renton Standard plan
5. Control Dewatering: Contain all turbid water and expose at the permitted site.
6. Control Other Pollutants (SWPPS).
7. Protect Existing and Proposed Flow Control BMPs
8. Maintain BMPs During Construction and Final Site Stabilization. BMPs shown on the attached
CSWPP plan is at minimum. Install additional BMPs as needed.
The contract shall implement the following construction notes where is applicable:
Standard ESC Plan Notes:
1. 1. The approved Construction Sequence shall be as follows:
a. Conduct pre-construction meeting.
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
b. Flag or fence clearing limits.
c. Post sign with name and phone number of TESC supervisor.
d. Install catch basin protection if required.
e. Grade and install construction entrance(s).
f. Install perimeter protection (silt fence, brush barrier, etc.).
g. Construct sediment ponds and traps.
h. Grade and stabilize construction roads.
i. Construct surface water controls (interceptor dikes, pipe slope drains, etc.)
simultaneously with clearing and grading for project development.
j. Maintain erosion control measure in accordance with City of Kirkland Standards and
manufacturer’s recommendations.
k. Relocate erosion control measures or install new measures so that as site conditions
change, the erosion and sediment control is always in accordance with the City TESC
minimum requirements.
l. Cover all areas within the specified time frame with straw, wood fiber mulch, compost,
plastic sheeting, crushed rock or equivalent.
m. Stabilize all areas that reach final grade within 7 days.
n. Seed or sod any areas to remain unworked for more than 30 days.
o. Upon completion of the project, all disturbed areas must be stabilized and best
management practices removed if appropriate.
2. All work and materials shall be in accordance with City of Kirkland standards and
specifications.
3. The implementation of this ESC plan and the construction, maintenance, replacement, and
upgrading of these ESC facilities is the responsibility of the Permittee/Contractor until all
construction is approved.
4. A copy of the approved ESC plans must be on the job site whenever construction is in
progress.
5. The ESC facilities shown on this plan must be constructed prior to or in conjunction with all
clearing and grading activities in such a manner as to ensure that sediment-laden water
does not enter the drainage system or violate applicable water standards. Wherever
possible, maintain natural vegetation for silt control.
6. The ESC facilities shall be constructed in accordance with the details on the approved plans.
Locations may be moved to suit field conditions, subject to approval by the Engineer and the
City of Kirkland Inspector.
7. The ESC facilities shown on this plan are the minimum requirements for anticipated site
conditions. During the construction period, these ESC facilities shall be upgraded (e.g.,
additional sumps, relocation of ditches and silt fences, etc.) as needed for unexpected storm
events. Additionally, more ESC facilities may be required to ensure complete siltation
control. Therefore, during the course of construction it shall be the obligation and
responsibility of the Contractor to address any new conditions that may be created by his
activities and to provide additional facilities over and above the minimum requirements as
may be needed.
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
8. The ESC facilities shall be inspected by the Permittee/Contractor daily during non-rainfall
periods, every hour (daylight) during a rainfall event, and at the end of every rainfall, and
maintained as necessary to ensure their continued functioning. In addition, temporary
siltation ponds and all temporary siltation controls shall be maintained in a satisfactory
condition until such time that clearing and/or construction is completed, permanent
drainage facilities are operational, and the potential for erosion has passed. Written records
shall be kept documenting the reviews of the ESC facilities.
9. The ESC facilities on inactive sites shall be inspected and maintained a minimum of once a
month or within 48 hours following a storm event.
10. Stabilized construction entrances shall be installed at the beginning of construction and
maintained for the duration of the project. Additional measures, such as wash pads, may be
required to ensure that all paved areas are kept clean for the duration of the project.
11. All denuded soils must be stabilized with an approved TESC method (e.g. seeding, mulching,
plastic covering, crushed rock) within the following timelines:
12. May 1 to September 30 – soils must be stabilized within 7 days of grading.
13. October 1 to April 30 – soils must be stabilized within 2 days of grading.
14. Stabilize soils at the end of the workday prior to a weekend, holiday, or predicted rain event.
15. Where seeding for temporary erosion control is required, fast germinating grasses shall be
applied at an appropriate rate (example: annual or perennial rye applied at approximately
80 pounds per acre).
16. Where straw mulch is required for temporary erosion control, it shall be applied at a
minimum thickness of 2".
17. All lots adjoining or having any native growth protection easements (NGPE) shall have a 6'
high temporary construction fence (chain link with pier blocks) separating the lot (or
buildable portions of the lot) from the area restricted by the NGPE and shall be installed
prior to any grading or clearing and remain in place until the Planning Department
authorizes removal.
18. Clearing limits shall be delineated with a clearing control fence. The clearing control fence
shall consist of a 6-ft. high chain link fence adjacent the drip line of trees to be saved,
wetland or stream buffers, and sensitive slopes. Clearing control fences along wetland or
stream buffers or upslope of sensitive slopes shall be accompanied by an erosion control
fence. If approved by the City, a four-foot high orange mesh clearing control fence may be
used to delineate clearing limits in all other areas.
19. Off-site streets must be kept clean at all times. If dirt is deposited on the public street
system, the street shall be immediately cleaned with power sweeper or other equipment.
All vehicles shall leave the site by way of the construction entrance and shall be cleaned of
all dirt that would be deposited on the public streets.
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
20. Rock for erosion protection of roadway ditches, where required, must be of sound quarry
rock, placed to a depth of 1' and must meet the following specifications: 4"-8" rock/40%-
70% passing; 2"-4" rock/30%-40% passing; and 1"-2" rock/10%-20%passing. Recycled
concrete shall not be used for erosion protection, including construction entrance or
temporary stabilization elsewhere on the site.
21. If any part(s) of the clearing limit boundary or temporary erosion/sedimentation control
plan is/are damaged, it shall be repaired immediately.
22. All properties adjacent to the project site shall be protected from sediment deposition and
runoff.
23. At no time shall more than 1' of sediment be allowed to accumulate within a catch basin. All
catch basins and conveyance lines shall be cleaned immediately following removal of
erosion control BMPs. The cleaning operation shall not flush sediment-laden water into the
downstream system.
24. Any permanent retention/detention facility used as a temporary settling basin shall be
modified with the necessary erosion control measures and shall provide adequate storage
capacity. If the permanent facility is to function ultimately as an infiltration or dispersion
system, the facility shall not be used as a temporary settling basin. No underground
detention tank, detention vault, or system which backs under or into a pond shall be used as
a temporary settling basin.
25. All erosion/sedimentation control ponds with a dead storage depth exceeding 6" must have
a perimeter fence with a minimum height of 3'.
26. The washed gravel backfill adjacent to the filter fabric fence shall be replaced and the filter
fabric cleaned if it is nonfunctional by excessive silt accumulation as determined by the City
of Kirkland. Also, all interceptor swales shall be cleaned if silt accumulation exceeds one-
quarter depth.
27. Prior to the October 1 of each year (the beginning of the wet season), all disturbed areas
shall be reviewed to identify which ones can be seeded in preparation for the winter rains.
The identified disturbed area shall be seeded within one week after October 1. A site plan
depicting the areas to be seeded and the areas to remain uncovered shall be submitted to
the Public Works Construction Inspector. The Inspector can require seeding of additional
areas in order to protect surface waters, adjacent properties, or drainage facilities.
28. Any area to be used for infiltration or pervious pavement (including a 5-foot buffer) must be
surrounded by silt fence prior to construction and until final stabilization of the site to
prevent soil compaction and siltation by construction activities.
29. If the temporary construction entrance or any other area with heavy vehicle loading is
located in the same area to be used for infiltration or pervious pavement, 6” of sediment
below the gravel shall be removed prior to installation of the infiltration facility or pervious
pavement (to remove fines accumulated during construction).
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
30. Any catch basins collecting runoff from the site, whether they are on or off the site, shall
have adequate protection from sediment. Catch basins directly downstream of the
construction entrance or any other catch basin as determined by the City Inspector shall be
protected with a “storm drain protection insert” or equivalent.
31. If a sediment pond is not proposed, a baker tank or other temporary ground and/or surface
water storage tank may be required during construction, depending on weather conditions.
32. Do not flush concrete by-products or trucks near or into the storm drainage system. If
exposed aggregate is flushed into the storm system, it could mean re-cleaning the entire
downstream storm system, or possibly re-laying the storm line.
33. Construction dewatering discharges shall always meet water quality guidelines listed in COK
Policy E-1. Specifically, discharges to the public stormwater drainage system must be below
25ntu, and not considered a prohibited discharge (per KMC 15.52.090). Temporary
discharges to sanitary sewer require prior authorization and permit from King County
Industrial Waste Program (206-263-3000) and notification to the Public Works Construction
Inspector.
34. Recycled concrete shall not be stockpiled on site, unless fully covered with no potential for
release of runoff.
Standard SWPPS Plan Notes:
1. All pollutants, including waste materials, that occur onsite shall be handled and disposed of
in a manner that does not cause contamination of stormwater.
2. Cover, containment, and protection from vandalism shall be provided for all chemicals,
liquid products, petroleum products, and non-inert wastes present on the site (see Chapter
173-304 WAC for the definition of inert waste). Onsite fueling tanks shall include secondary
containment.
3. 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 onsite using temporary plastic
placed beneath and, if raining, over the vehicle.
4. Application of agricultural chemicals, including fertilizers and pesticides, shall be conducted
in a manner and at application rates that will not result in loss of chemical to stormwater
runoff. Manufacturers' recommendations for application rates and procedures shall be
followed.
5. Measures shall be used to prevent or treat contamination of stormwater runoff by pH
modifying sources. These sources include, but are not limited to, bulk cement, cement kiln
dust, fly ash, new concrete washing and curing waters, waste streams generated from
concrete grinding and sawing, exposed aggregate processes, and concrete pumping and
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I-Kuan Tao Cultural Center 711 Monroe Ave NE Renton, Washington
mixer washout waters. Stormwater discharges shall not cause or contribute to a violation of
the water quality standard for pH in the receiving water.
Cobalt Geosciences, LLC
P.O. Box 82243
Kenmore, Washington 98028
www.cobaltgeo.com (206) 331-1097
May 14, 2018
Ms. Julie Chen
greenhousetex@comcast.net
RE: Stormwater Feasibility Evaluation
Proposed Development Expansion
711 Monroe Avenue NE
Renton, Washington
Dear Ms. Chen,
In accordance with your authorization, Cobalt Geosciences, LLC has prepared this letter to
discuss the results of our stormwater feasibility evaluation at the referenced site. The purpose of
our evaluation was to evaluate the shallow subsurface soil conditions and provide options for
stormwater management.
Site and Project Description
The site is located at 711 Monroe Avenue NE in Renton, Washington. The site consists of one
rectangular shaped parcel with a total area of about 13.552 square feet.
The western portion of the site is currently developed with a single-family residence used as a
business. A driveway extends through the north portion of the property from the east and
Monroe Avenue NE. The remainder of the property is vegetated with grasses, bushes, shrubs, and
sparse deciduous and evergreen trees. The site slopes gently downward toward the southwest and
west with topographic relief of less than 8 feet. There is a moderately steep slope extending
downward to the west in the area just west of the property. This area is well vegetated with low-
lying brush and variable diameter trees. The slope is up to 15 feet in height and has magnitudes of
30 percent.
The property is bordered to the north and west by single-family residences, to the south by a
commercial development, and to the east by Monroe Avenue NE.
The project includes construction of a second story to the existing residence as well as expanded
parking areas in the area between the building and Monroe Avenue NE. Stormwater
management may include permeable pavements, infiltration systems, rain gardens, or other
shallow best management practices (BMPs) from the King County Surface Water Design Manual.
Area Geology
The Geologic Map of King County indicates that the site is underlain by Vashon Glacial Till.
Vashon Glacial Till is typically characterized by an unsorted, non-stratified mixture of clay, silt,
sand, gravel, cobbles and boulders in variable quantities. These materials are typically dense and
relatively impermeable. The poor sorting reflects the mixing of the materials as these sediments
were overridden and incorporated by the glacial ice.
May 14, 2018
Page 2 of 3
Stormwater Feasibility Evaluation
www.cobaltgeo.com (206) 331-1097
Soil & Groundwater Conditions
As part of our evaluation, we excavated two hand borings up to 6 feet below grade. Both hand
borings encountered approximately 5 to 8 inches of topsoil and grass underlain by approximately
2 to 2.5 feet of loose to medium dense, silty-fine to fine grained sand with gravel (Weathered
Glacial Till). This layer was underlain by medium dense to dense, silty-fine to medium grained
sand with gravel (Glacial Till), which continued to the termination depths of the hand borings.
Soil mottling was observed in both hand borings from about 2 to 5 feet below existing grades. Soil
mottling (iron oxide staining) typically indicates the fluctuation level of seasonally perched
groundwater.
We also reviewed available exploration logs from nearby site locations, including across the street
to the east. The soils described in these boring and test pit logs were consistent with those
encountered in the hand borings.
Stormwater Management Feasibility
The site is underlain by glacial till which typically has a very low permeability. We conducted an
EPA Falling Head infiltration test in HB-1 at a depth of 3 feet below grade. The factored
infiltration rate was 0.28 inches/hour. The Washington State Department of Ecology (DOE)
states that infiltration in soils with permeability of less than 0.3 inches/hour is not recommended
and/or potentially infeasible.
It is our opinion that infiltration of stormwater runoff is not feasible due to the underlying soil
and groundwater conditions. The measured infiltration rates were less than 0.3 inches/hour in
the upper 4 feet. Infiltration rates in underlying unweathered glacial till are typically less than 0.1
inches/hour. Groundwater and infiltrating surface waters are likely to migrate laterally to the
southwest, potentially daylighting along the moderately steep slope west of the site.
Depending on the volume of runoff from the new parking areas and roof area, the following
stormwater management BMPs may be feasible:
x Dispersion trenches with limited flowpaths (roof area)
x Sheet flow (parking lots)
x Rain gardens
x Detention systems (R tanks or vaults)
x Permeable pavements for flow control
x Direct connection to City stormwater infrastructure
We recommend that all systems be located east of the existing building to reduce the potential for
impacts to the slope area west of the property. Based on our observations, a combination of
permeable pavements, rain gardens, and detention with overflow to City infrastructure appear
feasible.
It may be necessary to utilize one or more of the above BMPs for stormwater management. Once
the Civil designer has calculated volumes of runoff and has developed preliminary BMPs options,
we can provide additional input. We should review the final plans as they become available.
May 14, 2018
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Stormwater Feasibility Evaluation
www.cobaltgeo.com (206) 331-1097
Erosion and Sediment Control
Erosion and sediment control (ESC) is used to reduce the transportation of eroded sediment to
wetlands, streams, lakes, drainage systems, and adjacent properties. Erosion and sediment
control measures should be implemented, and these measures should be in general accordance
with local regulations. At a minimum, the following basic recommendations should be
incorporated into the design of the erosion and sediment control features for the site:
x Schedule the soil, foundation, utility, and other work requiring excavation or the disturbance
of the site soils, to take place during the dry season (generally May through September).
However, provided precautions are taken using Best Management Practices (BMP’s), grading
activities can be completed during the wet season (generally October through April).
x All site work should be completed and stabilized as quickly as possible.
x Additional perimeter erosion and sediment control features may be required to reduce the
possibility of sediment entering the surface water. This may include additional silt fences, silt
fences with a higher Apparent Opening Size (AOS), construction of a berm, or other filtration
systems.
x Any runoff generated by dewatering discharge should be treated through construction of a
sediment trap if there is sufficient space. If space is limited other filtration methods will need
to be incorporated.
Closure
The information presented herein is based upon professional interpretation utilizing standard
practices and a degree of conservatism deemed proper for this project. We emphasize that this
report is valid for this project as outlined above and for the current site conditions, and should not
be used for any other site
Sincerely,
Cobalt Geosciences, LLC
Phil Haberman, PE, LG, LEG
Principal
PH/sc
Proposed Parking Expansion
711 Monroe Avenue NE
Renton, Washington
SITE PLAN
FIGURE 1
Cobalt Geosciences, LLC
P.O. Box 82243
Kenmore, WA 98028
(206) 331-1097
www.cobaltgeo.com
cobaltgeo@gmail.com
N
HB-1
HB-1
HB-2
Log of Hand Boring HB-1
Date: May 2, 2018
Contractor:
Method: Hand Auger
Depth: 6’
Elevation: N/A
Logged By: PH Checked By: SC
Initial Groundwater: None
Sample Type: Grab
Final Groundwater: N/A
Material Description SPT N-Value
Moisture Content (%)Plastic
Limit
Liquid
Limit
10 20 30 400 50
1
2
3
4
5
6
7
8
9
10
End of Hand Boring 6’
Vegetation/Topsoil
Loose to medium dense, silty-fine to medium grained sand
with gravel and cobbles, dark yellowish brown to yellowish brown,
moist. (Weathered Glacial Till)
SM
Medium dense to dense, silty-fine to medium grained sand,
mottledyellowishbrowntograyishbrown,moist.(GlacialTill)
SM
Cobalt Geosciences, LLC
P.O. Box 82243
Kenmore, WA 98028
(206) 331-1097
www.cobaltgeo.com
cobaltgeo@gmail.com
Proposed Parking Expansion
711 Monroe Avenue NE
Renton, Washington
Hand Boring
Log
Log of Hand Boring HB-2
Date: May 2, 2018
Contractor:
Method: Hand Auger
Depth: 6’
Elevation: N/A
Logged By: PH Checked By: SC
Initial Groundwater: None
Sample Type: Grab
Final Groundwater: N/A
Material Description SPT N-Value
Moisture Content (%)Plastic
Limit
Liquid
Limit
10 20 30 400 50
1
2
3
4
5
6
7
8
9
10
End of Hand Boring 6’
Vegetation/Topsoil
Loose to medium dense, silty-fine to medium grained sand
with gravel and cobbles, dark yellowish brown to yellowish brown,
moist. (Weathered Glacial Till)
SM
Medium dense to dense, silty-fine to medium grained sand,
mottledyellowishbrowntograyishbrown,moist.(GlacialTill)
SM
Cobalt Geosciences, LLC
P.O. Box 82243
Kenmore, WA 98028
(206) 331-1097
www.cobaltgeo.com
cobaltgeo@gmail.com
Proposed Parking Expansion
711 Monroe Avenue NE
Renton, Washington
Hand Boring
Log
MONROE AVE NE30'
ROW
LANDSCAPING
LANDSCAPING
EXIST. CONC. PAVING TO BE REMAINED
EXIST. CONC. PAVING TO BE REMAINED
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MONROE AVE NE30'
ROW
LANDSCAPING
LANDSCAPING
EXIST. CONC. PAVING TO BE REMAINED
EXIST. CONC. PAVING TO BE REMAINED
REGI ST E R E D31169PROF
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N.T.S.
CONTROL MAP