21-101296-Preliminary TIR Report_08-16-2021-V2
255 S. King Street, Suite #800, Seattle, WA 98104 | 206.426.2600 | JACOBSONENGINEERS.COM
PRELIMINARY
TECHNICAL INFORMATION REPORT
for Storm Water Management
Olympic View K-8 School
2626 SW 327th ST, Federal Way, WA 98003
August 16, 2021
_______________________________________________
Prepared for
Federal Way Public Schools
33330 8th Avenue South
Federal Way, WA 98003
_______________________________________________
Prepared through
McGranahan Architects
2111 Pacific Ave #100
Tacoma, WA 98402
_______________________________________________
Prepared by
Jacobson Consulting Engineers
Sascha Eastman
(206) 426-2600
sascha@jacobsonengineers.com
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Preliminary Technical Information Report for
OLYMPIC VIEW K-8 SCHOOL
Project No. C200004-0081
August 16, 2021
TABLE OF CONTENTS
1. PROJECT OVERVIEW ......................................................................................................................... 3
GENERAL DESCRIPTION .............................................................................................................................. 3
EXISTING CONDITIONS ................................................................................................................................. 3
PROPOSED DRAINAGE SYSTEM ................................................................................................................. 4
2. CONDITIONS AND REQUIREMENTS SUMMARY .................................................................................. 5
CORE REQUIREMENT #1: DISCHARGE AT THE NATURAL LOCATION .................................................. 5
CORE REQUIREMENT #2: OFFSITE ANALYSIS ......................................................................................... 5
CORE REQUIREMENT #3: FLOW CONTROL .............................................................................................. 5
CORE REQUIREMENT #4: CONVEYANCE SYSTEM .................................................................................. 6
CORE REQUIREMENT #5: EROSION AND SEDIMENT CONTROL ........................................................... 6
CORE REQUIREMENT #6: MAINTENANCE AND OPERATIONS ............................................................... 6
CORE REQUIREMENT #7: FINANCIAL GUARANTEES .............................................................................. 7
CORE REQUIREMENT #8: WATER QUALITY .............................................................................................. 7
CORE REQUIREMENT #9: FLOW CONTROL BMP’S .................................................................................. 7
3. OFFSITE ANALYSIS ........................................................................................................................... 8
FIELD INSPECTION ........................................................................................................................................ 8
DRAINAGE SYSTEM PROBLEM DESCRIPTIONS ....................................................................................... 8
UPSTREAM ANALYSIS ................................................................................................................................... 8
DOWNSTREAM ANALYSIS ............................................................................................................................ 8
MITIGATION OF EXISTING OR POTENTIAL PROBLEMS ........................................................................... 9
4. FLOW CONTROL, LOW IMPACT DEVELOPMENT (LID) AND WATER QUALITY FACILITY ANALYSIS AND
DESIGN .................................................................................................................................................. 10
EXISTING SITE HYDROLOGY (PART A) ....................................................................................................10
DEVELOPED SITE HYDROLOGY (PART B) ...............................................................................................10
PERFORMANCE STANDARDS (PART C) ...................................................................................................11
FLOW CONTROL SYSTEM (PART D) .........................................................................................................11
WATER QUALITY SYSTEM (PART E) .........................................................................................................11
5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ............................................................................... 12
DEVELOPED STORM SYSTEM DESCRIPTION .........................................................................................12
OUTFALLS .....................................................................................................................................................12
CONVEYANCE CALCULATIONS DICUSSION ...........................................................................................12
6. SPECIAL REPORTS AND SUMMARY ................................................................................................. 13
7. OTHER PERMITS ............................................................................................................................ 14
8. CSWPP ANALYSIS AND DESIGN ...................................................................................................... 15
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ESC PLAN ANALYSIS AND DESIGN (PART A) ..........................................................................................15
SWPPPS PLAN DESIGN (PART B) ..............................................................................................................15
9. BOND QUANTITIES, FACILTY SUMMARIES, AND DECLARATION OF COVENANT ................................ 16
BOND QUANTITIES WORKSHEET..............................................................................................................16
FLOW CONROL AND WATER QUALITY FACILITY SUMMARY SHEET AND SKETCH .........................16
DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FLOW CONTROL AND WQ
FACILITIES .....................................................................................................................................................16
DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FLOW CONTROL BMP’S .................16
10. OPERATIONS AND MAINTENANCE MANUAL .................................................................................... 17
11. FIGURES ........................................................................................................................................ 18
12. APPENDICES .................................................................................................................................. 19
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1. PROJECT OVERVIEW
GENERAL DESCRIPTION
The following Drainage Report provides preliminary design analysis for the Olympic View K-8 School stormwater
plan. The stormwater design for the project is based on the requirements set forth in the 2016 King County
Surface Water Design Manual (2016 KCSWDM) as adopted by City of Federal Way, with addendums per City of
Federal Way Addendum to the King County Surface Water Design Manual (January 8, 2017).
Olympic View Elementary School is located at 2626 SW 327th ST, Federal Way, WA 98003 (See Figure 2 Vicinity
Map). The site is bounded by SW 327th Street to the south, condominiums, golf course, and single-family
residences to the west, 26th Ave SW to the east, and single-family residences to the north (see Figure 2, Vicinity
Map). The site is in the northwest quarter of Section 13, Township 21 North, Range 3 East, Willamette Meridian.
The area within the property boundary (parcel 132103-9008) is approximately 9.42 acres, of which approximately
7.2 acres will be redeveloped. The project will also be required to dedicate 30-feet of right-of-way along SW 327th
ST, which will decrease the property area by approximately 0.24 acres to be 9.18 acres.
The proposed project consists of redeveloping the entire school campus except for approximately 2.3 acres of
forested and vegetated land located along the west and north sides of the property, which will remain undisturbed.
The associated site redevelopment will consist of a new school building, including an outdoor natural learning
environment, an asphalt parking lot (staff and visitor) with a queuing and drop off lane, an asphalt bus loading area
w/ staff parking, asphalt playground (soft and hard play), and grass play field. Concrete and asphalt sidewalks are
also proposed to be constructed to provide pedestrian access through the site and will be ADA Accessible as
required to meet City of Federal Way standards and Federal Guidelines.
Frontage Improvements will also be implemented along both SW 327th ST to the south and 26th Ave SW to the
east. According to City of Federal Way guidelines provided in the March 11, 2021 Pre-Application Conference
Summary, SW 327th ST and 26th Ave SW and SW 327 are both classified as Minor Collector streets. Per City
Standards, the project will only be required to improve half the street frontages with both streets, measured from
the right-of-way (ROW) centerline, having a 10-ft drive lane, an 8-ft parking lane, a vertical curb, a 4-ft planter
strip, and a 5-ft concrete sidewalk.
EXISTING CONDITIONS
The existing Olympic View Elementary School campus is currently occupied with a 43,160 gross square foot school
building, a 42,200 square foot asphalt and wood chip play area with roughly 2,500 square feet of it covered, an
asphalt parent pickup-drop off area containing 17 parking stalls, an asphalt bus pickup-drop off, and approximately
27,000 square feet of usable grass space (See Figure 3 Existing Conditions). The parent pickup-drop off and
parking area located on the south side of the site has driveway access from both 26th Ave SW and SW 327th ST.
The bus pickup-drop off and delivery lane is on the east side of the existing school and is accessible via 26th Ave
SW with one-way circulation and (2) two driveways.
The stormwater for the existing building and south and east sides of the school generally drains to the SE corner of
the site via a series of downspout tightlines and catch basin and conveyance pipes, where it discharges into the
public storm system in 26th Ave SW, where it continues to flow to the north. The remainder of the site on the west
and north sides of the existing school campus sheet flows as overland flow across the property and onto adjacent
residential properties with some of the stormwater possibly draining to either cul-de-sac in 29th Ave SW, SW 324th
PL, or 26th PL SW streets. There are no offsite flows coming on the property.
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PROPOSED DRAINAGE SYSTEM
The stormwater design for the project is based on the requirements set forth in the 2016 King County Surface
Water Design Manual (2016 KCSWDM) as adopted by City of Federal Way, with addendums per City of Federal
Way Addendum to the King County Surface Water Design Manual (January 8, 2017). Based on projected
disturbances the development can expect to provide flow control for rainwater falling on new or replaced
impervious surfaces as well as redeveloped pervious surfaces. The amount of disturbed area for the site is
approximately 6.8 acres with roughly 2.4 acres of forested land being left undisturbed. Of the 6.8 acres of the site
that will be redeveloped, approximately 5.1 acres of new plus replaced impervious surface will be created, while
1.7 acres will be redeveloped as pervious surfacing (landscaping). Approximately 1.0 acre of field space will be
redeveloped that will be under-drained and by code definition, is considered 100% impervious. The field space is
accounted for in the 5.1 acres of redeveloped impervious area.
Preliminary Geotechnical Engineering findings indicate there is some deeper (not at the surface) outwash soils that
may be suitable for infiltration of on-site stormwater. Infiltration provides an opportunity for the project to
introduce stormwater runoff that would normally be collected and discharged off-site, back into the native outwash
soils that will help to contribute to recharging local aquifers and reduce possible impacts with any localized
downstream flooding. Currently for design, the geotechnical engineer has performed on-site infiltration field testing
and measured infiltration rates range from 4-inches per hour to 40-inches per hour. The geotechnical engineer has
added some correction factors to the field-tested rates to determine design infiltration rates in the range of 1.5-
inches per hour and 14.8-inches per hour, which results in design infiltration rates for the project ranging from
4.2-inches per hour to 7.8-inches per hour. The current design accounts for these design infiltration rates, with
the detention and storm drainage system being finalized and appropriately sized for the engineering permit
submittal. The project will include the infiltration testing report, prepared by the geotechnical engineer, as part of
the engineering permit submittal.
The project is required to provide Level 2 flow control and proposes to manage all required stormwater
management flows on-site and install a perforated CMP detention pipe with gravel finger drains (trenches) below
the pipe to provide a better hydraulic connection and infiltrate the stormwater into the native outwash soils. An
emergency overflow drain will be required to be installed and connected to the existing storm drainage system in
26th Ave SW, for stormwater flows above the 100-year storm event. Initial calculations, using infiltration rates of
7.5 and 7.8-inches per hour, indicate that approximately 28,500 cubic feet of stormwater detention is required to
be collected and infiltrated on-site. The storm detention/infiltration system is currently split into two separate
systems with CMP Detention System #1, using an infiltration rate of 7.8-inches per hour, will drain and infiltration
stormwater runoff for the north and east portions of site (field, asphalt play, a portion of building roof area, fire
lane, and the east parking lot). The CMP Detention System #2 with infiltrate of 7.5-inches per hour, will collect
and infiltration stormwater runoff from the south portion of the site (parking lot, bus loop drive, and a portion of
building roof area). Stormwater runoff from the central courtyard plaza space on the east side of the building, will
be drained to a rain garden and infiltrated into the native outwash soils up to the 100-year storm with stormwater
runoff above the 100-year storm to be conveyed to the storm system as emergency overflow. The stormwater
design for the redevelopment is ongoing but will be finalized and appropriately sized for the permit submittal.
Water quality treatment will also need to be addressed for the pollution generating impervious asphalt parking lot
and parent pickup-drop off and bus loading driveway located on the east and south sides of the site, respectively.
The project site will be required to provide enhanced basic water quality treatment of the stormwater runoff before
releasing the “clean” treated stormwater into the surrounding soils. The project proposes to install three (3) 4x6
Filterra vault systems, that will be installed upstream of detention prior to infiltrating the stormwater runoff on-site.
The Filterra vaults meet the City’s stormwater code requirement for water quality treatment. Upstream of the
Filterra vaults, the project also proposes to install three (3) Contech CDS Separators, which would be used to
separate out any solids (debris, trash, etc.) prior to stormwater entering the water quality treatment and infiltrating
detention systems, which will help to maintain and increase the overall life of the storm system.
Additionally, the grass athletic field is considered a pollution generating pervious surface and proposes to install
one (1) 4x6 Filterra vault to meet water quality treatment requirements.
Perimeter perforated footing drains will also be provided around the new building, to pick up any surface water or
incidental ground water from being trapped adjacent to the building foundation.
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2. CONDITIONS AND REQUIREMENTS SUMMARY
This section will address the Core Requirements set forth by the 2016 King County Surface Water Design Manual
as adopted by the City of Federal Way.
CORE REQUIREMENT #1: DISCHARGE AT THE NATURAL LOCATION
All storm water runoff and surface water from a project must be discharged at the natural location so as not to be
diverted onto or away from downstream properties. The manner in which stormwater runoff and surface water are
discharged from the project site must not create a significant adverse impact to downhill properties or drainage
facilities (see "Discharge Requirements" below). Drainage facilities as described above means a constructed or
engineered feature that collects, conveys, stores, treats, or otherwise manages surface water or stormwater runoff.
“Drainage facility” includes, but is not limited to, a constructed or engineered stream, lake, wetland, or closed
depression, or a pipe, channel, ditch, gutter, flow control facility, flow control BMP, water quality facility, erosion
and sediment control facility, and any other structure and appurtenance that provides for drainage. Note: Projects
that do not discharge all project site runoff at the natural location will require an approved adjustment of this
requirement (see Section 1.4). DPER may waive this adjustment, however, for projects in which only a small
portion of the project site does not discharge runoff at the natural location and the runoff from that portion is
unconcentrated and poses no significant adverse impact to downstream properties.
The project threshold area lies within a critical aquifer recharge area and proposes to manage all required
stormwater management flows on-site and install a perforated CMP detention pipe with gravel finger drains below
the pipe to infiltrate the stormwater into the native outwash soils. This will allow for the project to introduce
stormwater runoff back into the native outwash soils that will help to recharge local aquifers and reduce
contributions to localized downstream flooding.
The remainder of the site that will remain undisturbed, consisting of native vegetation and forest located along the
north and west sides of the property, will maintain existing natural drainage courses.
CORE REQUIREMENT #2: OFFSITE ANALYSIS
All proposed projects must submit an offsite analysis report that assesses potential offsite drainage and water
quality impacts associated with development of the project site, and that proposes appropriate mitigation of those
impacts. The initial permit submittal shall include, at minimum, a Level 1 downstream analysis as described in
Section 1.2.2.1 below. If impacts are identified, the proposed projects shall meet any applicable problem-specific
requirements specified in Section 1.2.2.2 (p. 1-32) for mitigation of impacts to drainage problems and Section
1.2.2.3 (p. 1-35) for mitigation of impacts to water quality problems.
A Level 1 downstream analysis will be provided, is discussed in additional detail in Section 3 below.
CORE REQUIREMENT #3: FLOW CONTROL
All proposed projects, including redevelopment projects, must provide onsite flow control facilities to mitigate the
impacts of storm and surface water runoff generated by new impervious surface, new pervious surface, and
replaced impervious surface targeted for flow mitigation as specified in the following sections. Flow control
facilities must be provided and designed to perform as specified by the area-specific flow control facility
requirement in Section 1.2.3.1 (p. 1-39) and in accordance with the applicable flow control facility
implementation requirements in Section 1.2.3.2 (p. 1-50).
The project is in a Conservation Flow Control Area and will be required to provide Level 2 flow control area, as
established from the City of Federal Way Flow Control Applications Map, which was also conveyed to us in the pre-
application meeting. The project is planning to install perforated CMP detention pipes that will infiltrate 100% of
the stormwater runoff on-site into the native outwash soils up to and including the 100-year storm event. Any
stormwater above the 100-year stormwater elevation, will be conveyed to the public storm system in 26th Ave SW.
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CORE REQUIREMENT #4: CONVEYANCE SYSTEM
All engineered conveyance system elements for proposed projects must be analyzed, designed, and constructed to
provide a minimum level of protection against overtopping, flooding, erosion, and structural failure as specified in
the following groups of requirements:
· "Conveyance Requirements for New Systems," Section 1.2.4.1 (below)
· "Conveyance Requirements for Existing Systems," Section 1.2.4.2 (p. 1-56)
· "Conveyance System Implementation Requirements," Section 1.2.4.3 (p. 1-57)
The new project will ensure that all stormwater drainage pipes are sized accordingly to convey the 100-year storm
event. A conveyance sizing analysis will be performed and presented as part of the engineering permit submittal
(Pending).
CORE REQUIREMENT #5: EROSION AND SEDIMENT CONTROL
All proposed projects that will clear, grade, or otherwise disturb the site must provide erosion and sediment
controls to prevent, to the maximum extent practicable, the transport of sediment from the project site to
downstream drainage facilities, water resources, and adjacent properties. All proposed projects that will conduct
construction activities onsite or offsite must provide stormwater pollution prevention and spill controls to prevent,
reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses. To
prevent sediment transport and pollutant discharges as well as other impacts related to land-disturbing and
construction activities, Erosion and Sediment Control (ESC) measures and Stormwater Pollution Prevention and
Spill Control (SWPPS) measures that are appropriate to the project site must be applied through a comprehensive
Construction Stormwater Pollution Prevention (CSWPP) plan as described in Sections 1.2.5.1 and 1.2.5.3 and
shall perform as described in Section 1.2.5.2. In addition, these measures, both temporary and permanent, shall
be implemented consistent with the requirements in Section 1.2.5.3 that apply to the proposed project.
A concept ESC plan with requirements for the Contractor to provide and implement a design for a system to treat
construction runoff to no more than 25 NTU’s over baseline is included with the submittal. A baseline will be
established at the start of construction and the contractor will be required to maintain levels no greater than 25
NTU’s above this level.
Our experience is that this is approach is much more realistic for both the bidding Contractor, development design
engineer, and the municipalities who are permitting and inspecting. We have found that if we take a “snapshot in
time” of what an ESC system may be and put that on the plans, it cannot consider all the phasing required to
construct the project and does not account for the contractors means and methods for how to manage a
construction site.
So often the bidding contractor submits a change order to the owner, saying we bid “the included ESC plan”, but
that design didn’t include any pump and filtration systems that may be necessary in conjunction with traditional
sediment settlement facilities, to treat the construction runoff to allowable discharge levels that work with the
contractors means and methods.
A SWPPP will be prepared and issued with the engineering permit submittal (Pending).
CORE REQUIREMENT #6: MAINTENANCE AND OPERATIONS
Maintenance and operation of all drainage facilities is the responsibility of the applicant or property
owner, except those facilities for which King County assumes maintenance and operation as described
below and in KCC 9.04.115 and KCC 9.04.120. Drainage facilities must be maintained and operated in
accordance with the maintenance standards in Appendix A of this manual, or other maintenance standards
as approved by King County.
A Maintenance and Operations Manual will be provided and issued with the engineering permit submittal
(Pending).
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CORE REQUIREMENT #7: FINANCIAL GUARANTEES
All drainage facilities constructed or modified for projects must comply with the financial guarantee requirements
in King County Ordinance 12020 and the liability requirements of King County Code 9.04.100, excepting those
privately maintained flow control BMPs not serving a private road designed for 2 or more lots. There are two types
of financial guarantees for projects constructing or modifying drainage facilities. These are as follows:
· The drainage facilities restoration and site stabilization guarantee
· The drainage defect and maintenance guarantee.
Since the owner is Federal Way Public Schools (FWPS) and a public agency, they are not subject to bonding
requirements. We are not aware if there is any other sort of Financial Guarantee that the City of Federal Way will
require, but FWPS is open to conversations to come up with a mutually agreeable solution.
CORE REQUIREMENT #8: WATER QUALITY
All proposed projects, including redevelopment projects, must provide water quality (WQ) facilities to treat the
runoff from those new and replaced pollution-generating impervious surfaces and new pollution-generating
pervious surfaces targeted for treatment as specified in the following sections. These facilities shall be selected
from a menu of water quality facility options specified by the area-specific facility requirements in Section 1.2.8.1
(p. 1-71) and implemented according to the applicable WQ implementation requirements in Section 1.2.8.2 (p. 1-
80).
Water Quality treatment is being provided for all of the targeted areas, which will provide Enhanced Basic Water
Quality Treatment via Filterra vaults. See Section 4, Part E, for additional discussion.
CORE REQUIREMENT #9: FLOW CONTROL BMP’S
All proposed projects, including redevelopment projects, must provide onsite flow control BMPs to mitigate the
impacts of storm and surface water runoff generated by new impervious surface, new pervious surface, existing
impervious surfaces, and replaced impervious surface targeted for mitigation as specified in the following sections.
Flow control BMPs must be selected and applied according to the basic requirements, procedures, and provisions
detailed in this section and the design specifications for each BMP in Appendix C, Section C.2.
Flow control BMPs are methods and designs for dispersing, infiltrating, or otherwise reducing or preventing
development-related increases in runoff at or near the sources of those increases. Flow control BMPs include, but
are not limited to, preservation and use of native vegetated surfaces to fully disperse runoff; use of other pervious
surfaces to disperse runoff; roof downspout infiltration; permeable pavements; bioretention; limited infiltration
systems; and reduction of development footprint.
The project proposes to manage all required stormwater management flows on-site and install a perforated CMP
detention pipe with gravel finger drains below the pipe to infiltrate the stormwater into the native outwash soils.
The remainder of the site that will remain undisturbed, consisting of native vegetation and forest located along the
north and west sides of the property, will maintain existing natural drainage courses via overland sheet flow.
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3. OFFSITE ANALYSIS
FIELD INSPECTION
Site visits were made in the fall of 2020 and winter of 2021 to gather information about the existing drainage
system, including a Level 1 Downstream Analysis. The project survey, existing record drawings and City GIS
information have also been utilized as a resource for the discussion below. Please refer to Downstream Analysis
below for more information.
DRAINAGE SYSTEM PROBLEM DESCRIPTIONS
The school district, or City of Federal Way to our knowledge, has not raised concerns about any existing drainage
problems. As such, no drainage problems are anticipated to be present in the redevelopment as a result of
previously existing problems.
UPSTREAM ANALYSIS
There are not upstream drainage areas that currently contribute runoff to the Olympic View K8 School property.
However, redevelopment of the frontages along both SW 327th ST and 26th Ave SW, will result in a portion of new
roadway to be constructed where either gravel parking or rolled curb exists, respectively. Both streets are proposed
to be reconditioned with a grind and overlay, which does not trigger stormwater detention or water quality treatment
measures to be implemented.
We are anticipating that the amount of new plus replaced impervious surfacing in the right-of-way, which consists
of concrete sidewalks and new plus replaced asphalt roadway will be less than 10,000 square feet and therefore
not triggering stormwater flow control requirements. The amount of new PGIS asphalt pavement is also anticipated
to be less than 5,000 square feet, which does not trigger then the threshold requirement for water quality
treatment. However, for budgetary purposes, the project is currently installing a Filterra Unit for water quality
treatment in both SW 327th ST and 26th Ave SW and routing the stormwater runoff to the project’s on-site
stormwater detention infiltration system. As the design is finalized, we anticipate the project will not include water
quality treatment or flow control for any portion of the redeveloped right-of-way and will be reflected in the permit
submittal (Pending).
DOWNSTREAM ANALYSIS
The existing on-site piped stormwater conveyance connection to the existing public storm system in the right-of-
way, is located at the SE corner of the property (See Figure 7 City OLV Outfall POC). The point of compliance for
the site is at the approximate intersection of 26th Ave SW and SW 323rd ST, where the stormwater runoff flows
along 26th Ave SW and a portion of SW 323rd ST to the west, including approximately half of the cul-de-sac for 26th
PL SW, converge and outfall to the existing private Lake Ponce de Leon.
There are (3) drainage basins located on the existing development (See Figure 3 Existing Conditions). A portion of
Basin A (sub-basin) collects stormwater runoff from the roof and pavements on the south and east sides of the site
and is drained to a series of catch basins and piped conveyance system. The stormwater from this basin enters the
city’s storm drainage system in the SE corner of the site as described above. The remaining portions of Basin A
(central and north sub-basins) sheet flow stormwater runoff across landscape areas and vegetated slopes and drains
onto the pavement in 26th Ave SW. Basin B is located on the west side of the site and drains stormwater via
overland flow across the existing asphalt play surfacing, play field, and adjacent grass hillside to the west that
generally drains from south to north with (2) apparent flow paths, one to the west hillside and the other to the
northwest corner. These flow paths are approximate and not clearly defined as there are no defined conveyance
ditches or channels are assumed to drain onto the neighboring residential properties to the west. The last drainage
basin, Basin C, is located between the existing field and property line and consists of sloped vegetated and forest
that slopes to the north, and also includes approximately half the grass playfield.
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Main Site, South and East (Basin A)
Stormwater runoff that is collected and conveyed to the southeast corner of the property, is conveyed to the public
storm drainage system that varies in pipe size and material ranging from 12-inch diameter to 32-inch diameter and
concrete and corrugated metal pipe, respectively. The stormwater travels through the existing City storm drainage
system to the north along 26th Ave SW until it reaches the intersection of 26th Ave SW and SW 325th ST, at
which point the stormwater is conveyed to the northeast direction through a 30-inch diameter concrete pipe that
outfalls into in a private lake listed on Google Maps as Lake Ponce de Leon. The lake outfall is located roughly
1,200 feet from the existing Olympic View Elementary School stormwater POC (See Figure 6 Downstream
Analysis).
West (Basin B) and North (Basin C)
The north and west sides of the existing school campus sheet flows stormwater across the site to the north,
northeast, northwest, and west directions as described above where it is believed, based on contour data, the
stormwater runoff makes its way to the cul-de-sacs of 26th PL SW, SW 324th PL, and 29th Ave SW through or
across neighboring residential properties. The stormwater runoff then sheet flows along existing rolled curb and
gutters until the stormwater is collected in catch basins in SW 323rd ST and conveyed either west or east.
Stormwater along the curb flowline travels west to roughly the intersection of SW 323rd ST and 32nd Ave SW,
where it is a quarter mile (0.25 mi) from where the stormwater runoff from the site enters the public street and
drainage system. A portion of stormwater runoff along 26th PL SW, travels north, then east along SW 323rd ST
until is eventually discharged to private Lake Ponce de Leon (See Figure 5 Downstream Quarter Mile Map).
MITIGATION OF EXISTING OR POTENTIAL PROBLEMS
The school district, or City of Federal Way to our knowledge, has not raised concerns about any existing drainage
problems. As such, no drainage problems are anticipated to be present in the redevelopment as a result of
previous existing problems.
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4. FLOW CONTROL, LOW IMPACT DEVELOPMENT (LID) AND WATE R
QUALITY FACILITY ANALYSIS AND DESIGN
EXISTING SITE HYDROLOGY (PART A)
The existing site totals approximately 9.42 acres and consists of the existing school building, parking lots,
landscaping, sidewalks, hard and soft play areas, and sports field. The stormwater for the existing building and
south and east sides of the school generally drains to the SE corner of the site via a series of downspout tightlines
and catch basin and conveyance pipes, where it discharges into the public storm system in 26th Ave SW, where it
continues to flow to the north. The remainder of the site on the west and north sides of the existing school campus
sheet flows as overland flow across the property and onto adjacent residential properties with some of the
stormwater possibly draining to either cul-de-sac in 29th Ave SW, SW 324th PL, or 26th PL SW streets. There are no
offsite flows coming on the property.
Table 1 summarizes the land cover characteristics of the of the existing current site (See Figure 3 Existing
Conditions) excluding 30-ft ROW Dedication property adjustment.
TABLE 1 – EXISTING SITE CONDITIONS – AREA BREAKDOWN S
Land Cover Area (acres)
Impervious Area 3.46
Landscape Area 3.69
Forested Area (Undisturbed) 2.27
Total Site 9.42
% Impervious of Site 36.7%
DEVELOPED SITE HYDROLOGY (PART B)
Storm water mitigation will be required for construction of the new project redevelopment. This will include all
disturbed site areas. Table 2 summarizes the land cover characteristics of the proposed redevelopment with 30-ft
ROW Dedication property adjustment (See Figure 4 New + Replaced Impervious Areas).
TABLE 2 –DEVELOPED SITE CONDITIONS AREA BREAKDOWN
Land Cover Area (acres)
Impervious Area 5.13
Landscape Area 1.67
Forested Area (Undisturbed) 2.38
Total Site 9.18
% Impervious of Site 55.9%
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PERFORMANCE STANDARDS (PART C)
The project is in a Conservation Flow Control Area and will be required to provide Level 2 flow control area, as
established from the City of Federal Way Flow Control Applications Map and conveyed to us in the pre-application
meeting. In accordance with the 2016 KCSWDM manual, MGSFlood Version 4 (an accepted continuous-modeling
software) will be used to model the runoff from existing and proposed site drainage basins. Existing site
development conditions were modeled as having forested surface cover. New and replaced impervious areas are
modeled as impervious surfaces. However, since the project is proposing to infiltrate 100% of the stormwater
runoff into the native outwash soils up to and including the 100-year storm event, the project is not required to
match existing stormwater flow durations.
FLOW CONTROL SYSTEM (PART D)
Flow control for the disturbed site areas of the redeveloped property, will be provided with perforated CMP
detention pipe and gravel finger drains below the pipe to infiltrate the stormwater for up to and including the 100-
year storm, into the native outwash soils. Initial calculations, using an infiltration rate of 7.8-inches per hour for
CMP Detention System #1 and 7.5-inches per hour for CMP Detention System #2, indicate that approximately
28,500 cubic feet of stormwater detention is required to be collected and infiltrated on-site. The proposed CMP
detention/infiltration system provides approximately 29,960 cubic feet and includes 6-inches of sediment storage
and 6-inches of freeboard at top of pipe, and a design factor of safety of roughly 5.0%.
The storm detention/infiltration system is currently split into two separate systems with CMP Detention System #1,
using an infiltration rate of 7.8-inches per hour, will drain and infiltration stormwater runoff for the north and east
portions of site (field, asphalt play, a portion of building roof area, fire lane, and the east parking lot). The CMP
Detention System #2 with infiltrate of 7.5-inches per hour, will collect and infiltration stormwater runoff from the
south portion of the site (parking lot, bus loop drive, and a portion of building roof area). Stormwater runoff from
the central courtyard plaza space on the east side of the building, will be drained to a rain garden and infiltrated
into the native outwash soils up to the 100-year storm with stormwater runoff above the 100-year storm to be
conveyed to the storm system as emergency overflow. The stormwater design for the redevelopment is ongoing but
will be finalized and appropriately sized for the permit submittal.
See Appendix A for preliminary Flow Control Calculations.
WATER QUALITY SYSTEM (PART E)
Water quality treatment will need to be provided for the pollution generating impervious asphalt parking lot, and
parent pickup-drop off and bus loading driveway located on the east and south sides of the site, respectively, as
well as the grass athletic field, which is considered a pollution generating pervious area.
For the asphalt parking lots and bus loading driveway, the project proposes to install three (3) 4x6 Filterra vault
systems, that will be installed upstream of detention prior to infiltrating the stormwater runoff on-site. The Filterra
vaults meet the City’s stormwater code requirement for water quality treatment. Upstream of the Filterra vaults,
the project also proposes to install three (3) Contech CDS Separators, which would be used to separate out any
solids (debris, trash, etc.) prior to stormwater entering the water quality treatment and infiltrating detention
systems, which will help to maintain and increase the overall life of the storm system.
Additionally, the grass athletic field is considered a pollution generating pervious surface and proposes to install
one (1) 4x6 Filterra vault to meet water quality treatment requirements.
Water Quality Calculations for the sizing of the water quality treatment facilities will be provided in the engineering
permit submittal (Pending).
12
5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
This section discusses the criteria that will be used to analyze and design the proposed storm conveyance system
(Pending).
DEVELOPED STORM SYSTEM DESCRIPTION
Section will be updated for the engineering permit submittal.
OUTFALLS
Section will be updated for the engineering permit submittal.
CONVEYANCE CALCULATIONS DICUSSION
Section will be updated for the engineering permit submittal.
13
6. SPECIAL REPORTS AND SUMMARY
Please refer to Geotech Report by Associated Earth Sciences Inc. - "SUBSURFACE EXPLORATION, GEOLOGIC
HAZARD, INFILTRATION DESIGN, AND GEOTECHNICAL ENGINEERING REPORT" – MARCH 30, 2021.
14
7. OTHER PERMITS
Land Use Process III Submittal – PENDING
Building Permit – PENDING
Engineering (EN) Permit – PENDING
15
8. CSWPP ANALYSIS AND DESIGN
ESC PLAN ANALYSIS AND DESIGN (PART A)
Section will be updated for the engineering permit submittal.
SWPPPS PLAN DESIGN (PART B)
A SWPPP will be prepared for this project and included with the engineering permit submittal.
16
9. BOND QUANTITIES, FACILTY SUMMARIES, AND DECLARATION OF
COVENANT
BOND QUANTITIES WORKSHEET
A Bond Quantity Worksheet will not be required, unless requested by the City of Federal Way.
FLOW CONROL AND WATER QUALITY FACILITY SUMMARY SHEET AND SKETCH
Flow Control and Water Quality Facility Summary Sheets and sketches will be included with the engineering permit
submittal (Pending).
DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FLOW CONTROL AND WQ
FACILITIES
King County’s standard Declaration of Covenant for Privately Maintained Flow Control and WQ Facilities will be
included with the permit submittal for City of Federal Way review and comment prior to recording. It is anticipated
that if this document is required, that it would be just one document that would be utilized for all the new facilities
installed as part of this project: 1) Perforated CMP Pipes, and 2) Filterra Units.
DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FLOW CONTROL BMP’S
King County’s standard Declaration of Covenant for Maintenance and Inspection of Flow Control BMP’s will be
included with the permit submittal for City of Federal Way review and comment prior to recording.
17
10. OPERATIONS AND MAINTENANCE MANUAL
An Operations and Maintenance Manual will be included with the engineering permit submittal.
18
11. FIGURES
Figure 1 – TIR Worksheet
Figure 2 – Vicinity Map
Figure 3 – Existing Conditions
Figure 4 – New + Replaced Impervious Areas
Figure 5 – Downstream Quarter Mile Map
Figure 6 – Downstream Analysis Exhibit
Figure 7 – City OLV Outfall POC
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER Part 2 PROJECT LOCATION AND
DESCRIPTION
Project Owner ___________________________
Phone _________________________________
Address _______________________________
_______________________________________
Project Engineer _________________________
Company ______________________________
Phone _________________________________
Project Name _________________________
DPER Permit # ________________________
Location Township ______________
Range ________________
Section ________________
Site Address __________________________
_____________________________________
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
Landuse (e.g.,Subdivision / Short Subd. / UPD)
Building (e.g.,M/F / Commercial / SFR)
Clearing and Grading
Right-of-Way Use
Other _______________________
DFW HPA
COE 404
DOE Dam Safety
FEMA Floodplain
COE Wetlands
Other ________
Shoreline
Management
Structural
Rockery/Vault/_____
ESA Section 7
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review
(check one):
Date (include revision
dates):
Date of Final:
Full
Targeted
Simplified
Large Project
Directed
__________________
__________________
__________________
Plan Type (check
one):
Date (include revision
dates):
Date of Final:
Full
Modified
Simplified
__________________
__________________
__________________
Part 6 SWDM ADJUSTMENT APPROVALS
Type (circle one): Standard / Experimental / Blanket
Description: (include conditions in TIR Section 2)
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
Approved Adjustment No. ______________________ Date of Approval: ______________________
2016 Surface Water Design Manual 4/24/2016
1
FWPS
(503) 477-2036
33330 8th Ave South
Federal Way, WA 98003
Sascha Eastman
Jacobson Consulting Engineers
(206) 426-2600
Olympic View Elementary K-8
N/A
21 N
2626 SW 327th ST
Federal Way, WA 98033
3 E
13
Rep. (Mike Kwaske)
FIGURE 1: TIR WORKSHEET
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes / No
Start Date: _______________________
Completion Date: _______________________
Describe: _________________________________
_________________________________________
_________________________________________
Re: KCSWDM Adjustment No. ________________
Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan : ____________________________________________________________________
Special District Overlays: ______________________________________________________________
Drainage Basin: _____________________________________________________________________
Stormwater Requirements: ____________________________________________________________
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
River/Stream ________________________
Lake ______________________________
Wetlands ____________________________
Closed Depression ____________________
Floodplain ___________________________
Other _______________________________
_______________________________
Steep Slope __________________________
Erosion Hazard _______________________
Landslide Hazard ______________________
Coal Mine Hazard ______________________
Seismic Hazard _______________________
Habitat Protection ______________________
_____________________________________
Part 10 SOILS
Soil Type
_________________
_________________
_________________
_________________
Slopes
_________________
_________________
_________________
_________________
Erosion Potential
_________________
_________________
_________________
_________________
High Groundwater Table (within 5 feet)
Other ________________________________
Sole Source Aquifer
Seeps/Springs
Additional Sheets Attached
2016 Surface Water Design Manual 4/24/2016
2
DUMAS BAY
TOP SOIL
SEE GEOTECH REPORT BY AESI - "SUBSURFACE EXPLORATION,
GEOLOGIC HAZARD, INFILTRATION DESIGN, AND PRELIMINARY
GEOTECHNICAL ENGINEERING REPORT" - MARCH 30, 2021
10-YEAR WELLHEAD CAPTURE ZONE
FOR CRITICAL AQUIFER RECHARGE
AREA
DENSE SAND
ADVANCED OUTWASH
FIGURE 1: TIR WORKSHEET
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE
Core 2 – Offsite Analysis_________________
Sensitive/Critical Areas__________________
SEPA________________________________
LID Infeasibility________________________
Other________________________________
_____________________________________
LIMITATION / SITE CONSTRAINT
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area)
Threshold Discharge Area:
(name or description)
Core Requirements (all 8 apply):
Discharge at Natural Location Number of Natural Discharge Locations:
Offsite Analysis Level: 1 / 2 / 3 dated:__________________
Flow Control (include facility
summary sheet)
Level: 1 / 2 / 3 or Exemption Number ____________
Flow Control BMPs _______________________________
Conveyance System Spill containment located at: _________________________
Erosion and Sediment Control /
Construction Stormwater
Pollution Prevention
CSWPP/CESCL/ESC Site Supervisor: _____________________
Contact Phone: _________________________
After Hours Phone: _________________________
Maintenance and Operation
Responsibility (circle one): Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and
Liability
Provided: Yes / No
Water Quality (include facility
summary sheet)
Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog
or Exemption No. ______________________
Landscape Management Plan: Yes / No
Special Requirements (as applicable):
Area Specific Drainage
Requirements
Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None
Name: ________________________
Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None
100-year Base Flood Elevation (or range): ______________
Datum:
Flood Protection Facilities Describe:
2016 Surface Water Design Manual 4/24/2016
3
TBD - WILL BE
PROVIDED PRIOR TO
PERMIT ISSUEANCE
FWPS TO PROVIDE AS
NEGOTIATED WITH C.O.F.W.
Disturbed Redeveloped Site Area
LAST CB BEFORE PIPE
CONNECT TO EX. SD
FIGURE 1: TIR WORKSHEET
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area)
Source Control
(comm ercial / industrial land use)
Describe land use:
Describe any structural controls:
Oil Control
High-use Site: Yes / No
Treatment BMP: ________________________________
Maintenance Agreement: Yes / No
with whom? ____________________________________
Other Drainage Structures
Describe:
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
Clearing Limits
Cover Measures
Perimeter Protection
Traffic Area Stabilization
Sediment Retention
Surface Water Collection
Dewatering Control
Dust Control
Flow Control
Protection of Flow Control BMP Facilities
(existing and proposed)
Maintain BMPs / Manage Project
MINIMUM ESC REQUIREMENTS
AFTER CONSTRUCTION
Stabilize exposed surfaces
Remove and restore Temporary ESC Facilities
Clean and remove all silt and debris, ensure
operation of Permanent Facilities, restore
operation of Flow Control BMP Facilities as
necessary
Flag limits of SAO and open space preservation
areas
Other ______________________
Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch)
Flow Control Type/Description Water Quality Type/Description
Detention
Infiltration
Regional Facility
Shared Facility
Flow Control BMPs
Other
________________
________________
________________
________________
________________
________________
Vegetated Flowpath
Wetpool
Filtration
Oil Control
Spill Control
Flow Control BMPs
Other
________________
________________
________________
________________
________________
________________
________________
2016 Surface Water Design Manual 4/24/2016
4
Filterra Vaults / PGIS Surfaces
Pipe / Bldg and Site
FIGURE 1: TIR WORKSHEET
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS
Drainage Easement
Covenant
Native Growth Protection Covenant
Tract
Other ___________________________
Cast in Place Vault
Retaining Wall
Rockery > 4’ High
Structural on Steep Slope
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 Information Report. To the best of my
knowledge the information provided here is accurate.
Signed/Date
2016 Surface Water Design Manual 4/24/2016
5
FIGURE 1: TIR WORKSHEET
255 S. King Street, Suite 800, Seattle, WA 98104 | 206.399.6233 | JACOBSONENGINEERS.COM
FIGURE 2: VICINITY MAP
SCALE: NTS
206.426.2600
Project Site
Project Site
FIGURE 3: EXISTING CONDITIONSNOTE:SHEET HAS BEENPRINTED TO BE 11X17AND NOT TO SCALEBASIN A(DRAINS TO26th AVE SW)BASIN B(DRAINS TOSW 323rd ST via29th AVE SW)BASIN C(DRAINS TOSW 323rd ST)
FIGURE 4: NEW + REPLACED IMPERVIOUS AREASNOTE:SHEET HAS BEENPRINTED TO BE 11X17AND NOT TO SCALE
APPROXIMATE 1/4MILE DOWNSTREAM(BASINS B AND C)APPROXIMATEPATHS BASED ONCONTOUR DATA(TYP)EXISTING OLV POC TOPRIVATE LAKE PONCE DELEON AND APPROXIMATE1/4 MILE DOWNSTREAM(BASINS A AND PORTIONOF C) - SEE FIGURE 7FIGURE 5: DOWNSTREAM QUARTER MILE MAPBASIN BBASIN CBASIN ASTORMWATERRUNOFF SPLITSIN 26th PL SW
EXISTING STORMWATERFLOW DIRECTIONLEGENDON-SITE POINT-OF-CONNECTIONOR SHEET FLOW RUNOFF TO ROW26th Ave SWSW 327th STSW 326th ST (1 of 6)_FIGURE 6: DOWNSTREAM ANALYSIS EXHIBITNOTE:SHEET HAS BEENPRINTED TO BE 11X17AND NOT TO SCALE
26th Ave SWSW 325th PLSW 325th ST (2 of 6)_FIGURE 6: DOWNSTREAM ANALYSIS EXHIBITEXISTING STORMWATERFLOW DIRECTIONLEGENDON-SITE POINT-OF-CONNECTIONOR SHEET FLOW RUNOFF TO ROWNOTE:SHEET HAS BEENPRINTED TO BE 11X17AND NOT TO SCALE
EXISTING STORMWATER FLOW DIRECTIONSTORMWATER FLOW DIRECTIONON-SITE POINT-OF-CONNECTIONLEGEND26th Ave SWSW 323rd ST (3 of 6)_FIGURE 6: DOWNSTREAM ANALYSIS EXHIBITEXISTING STORMWATERFLOW DIRECTIONLEGENDON-SITE POINT-OF-CONNECTIONOR SHEET FLOW RUNOFF TO ROWNOTE:SHEET HAS BEENPRINTED TO BE 11X17AND NOT TO SCALE
26th Ave SWSW 325th PLSW 325th STSW 323rd STEXISTING STORMWATERFLOW DIRECTIONLEGEND(4 of 6)_FIGURE 6: DOWNSTREAM ANALYSIS EXHIBITNOTE:SHEET HAS BEENPRINTED TO BE 11X17AND NOT TO SCALE
(5 of 6)_FIGURE 6: DOWNSTREAM ANALYSIS EXHIBITNOTE:SHEET HAS BEENPRINTED TO BE 11X17AND NOT TO SCALE26th Ave SWSW 323rd STSW 323rd ST26th Ave SWEND OF 1/4 MILEDOWNSTREAM OF SITEOLV CAMPUSEXISTING STORMWATERFLOW DIRECTIONLEGENDSTORMWATER SHEETFLOW ALONG EXISTINGCURB LINEAPPROXIMATESTORMWATER SHEETFLOW PATH FROM OLV(ASSUMED)26th PL SW
(6 of 6)_FIGURE 6: DOWNSTREAM ANALYSIS EXHIBITNOTE:SHEET HAS BEENPRINTED TO BE 11X17AND NOT TO SCALEOLV CAMPUSEXISTING STORMWATERFLOW DIRECTIONLEGENDSTORMWATER SHEETFLOW ALONG EXISTINGCURB LINEAPPROXIMATESTORMWATER SHEETFLOW PATH FROM OLV(ASSUMED)SW 323rd ST29th Ave S
WSW 324th PLEND OF 1/4 MILEDOWNSTREAM OF SITE
D97691
D98672
2122
CV2
26TH AVE SWSW 327TH ST
SW 326TH ST
SW 325TH PL
SW 328TH ST
Commercial Site Inspection Map
ÜSite Address: 2626 SW 327th ST D97691
#1
FIGURE 7: CITY OLV OUTFALL POC
19
12. APPENDICES
Appendix A – Preliminary Calculations
Appendix B – AESI “SUBSURFACE EXPLORATION, GEOLOGIC HAZARD, INFILTRATION DESIGN, AND
GEOTECHNICAL ENGINEERING REPORT”
Appendix C – Operation & Maintenance Manual (PENDING)
Appendix D – Conveyance Calculations and Exhibits (PENDING)
Appendix E – Bond Quantities, Facility Summaries, and Declaration of Covenant (PENDING)
20
Appendix A
Preliminary Calculations
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.54
Program License Number: 201910001
Project Simulation Performed on: 08/10/2021 1:34 PM
Report Generation Date: 08/10/2021 1:34 PM
—————————————————————————————————
Input File Name: 2021-08-03 OLVK8 Detention Cals_Infiltration_Large Pipes.fld
Project Name: OVES K8 Redevelopment
Analysis Title: Basin A Detention Sizing Design w/ Infiltration (7.8"/hr)
Comments: Field is underdrained and 100% Impervious
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 15
Extended Precipitation Time Series Selected
Climatic Region Number: 15
Full Period of Record Available used for Routing
Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961040 Puget East 40 in MAP
Evaporation Scale Factor : 0.750
HSPF Parameter Region Number: 1
HSPF Parameter Region Name : USGS Default
********** Default HSPF Parameters Used (Not Modified by User) ***************
********************** WATERSHED DEFINITION ***********************
Predevelopment/Post Development Tributary Area Summary
Predeveloped Post Developed
Total Subbasin Area (acres) 5.298 5.298
Area of Links that Include Precip/Evap (acres) 0.000 0.000
Total (acres) 5.298 5.298
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Forest 5.298
----------------------------------------------
Subbasin Total 5.298
STORM FLOW CONTROL - INFILTRATION SIZING CALCULATIONS
CMP Detention System #1
P R E L I M I N A R Y
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Grass 1.226
Impervious 4.072
----------------------------------------------
Subbasin Total 5.298
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
------------------------------------------
Link Name: Detention Vault
Link Type: Structure
Downstream Link: None
Prismatic Pond Option Used
Pond Floor Elevation (ft) : 278.00
Riser Crest Elevation (ft) : 285.00
Max Pond Elevation (ft) : 285.50
Storage Depth (ft) : 7.00
Pond Bottom Length (ft) : 91.4
Pond Bottom Width (ft) : 34.0
Pond Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00
Bottom Area (sq-ft) : 3108.
Area at Riser Crest El (sq-ft) : 3,108.
(acres) : 0.071
Volume at Riser Crest (cu-ft) : 21,753.
(ac-ft) : 0.499
Area at Max Elevation (sq-ft) : 3108.
(acres) : 0.071
Vol at Max Elevation (cu-ft) : 23,307.
(ac-ft) : 0.535
Constant Infiltration Option Used
Infiltration Rate (in/hr): 7.80
Riser Geometry
Riser Structure Type : Circular
Riser Diameter (in) : 12.00
Common Length (ft) : 0.000
Riser Crest Elevation : 285.00 ft
STORM FLOW CONTROL - INFILTRATION SIZING CALCULATIONS
CMP Detention System #1
INCLUDES 6-INCHES SEDIMENT STORAGE
& 6-INCHES FREEBOARDP R E L I M I N A R Y
Hydraulic Structure Geometry
Number of Devices: 0
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
Number of Links: 1
********** Link: Detention Vault ********** Link WSEL
Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) WSEL Peak (ft)
======================================
1.05-Year 278.414
1.11-Year 278.611
1.25-Year 278.724
2.00-Year 279.299
3.33-Year 279.851
5-Year 280.423
10-Year 281.527
25-Year 283.076
50-Year 284.224
100-Year 284.980
***********Groundwater Recharge Summary *************
Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures
Total Predeveloped Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 913.529
_____________________________________
Total: 913.529
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 149.830
Link: Detention Vault 2072.213
_____________________________________
Total: 2222.044
Total Predevelopment Recharge is Less than Post Developed
STORM FLOW CONTROL - INFILTRATION SIZING CALCULATIONS
CMP Detention System #1
EMERGENCY OVERFLOW ELEVATION
P R E L I M I N A R Y
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 5.782 ac-ft/year, Post Developed: 14.064 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
********** Link: Detention Vault **********
Basic Wet Pond Volume (91% Exceedance): 19284. cu-ft
Computed Large Wet Pond Volume, 1.5*Basic Volume: 28926. cu-ft
Time to Infiltrate 91% Treatment Volume, (Hours): 9.55
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 2072.23
Inflow Volume Including PPT-Evap (ac-ft): 2072.23
Total Runoff Infiltrated (ac-ft): 2072.21, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
***********Compliance Point Results *************
Scenario Predeveloped Compliance Subbasin: Subbasin 1
Scenario Postdeveloped Compliance Link: Detention Vault
*** Point of Compliance Flow Frequency Data ***
Recurrence Interval Computed Using Gringorten Plotting Position
Predevelopment Runoff Postdevelopment Runoff
Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs)
----------------------------------------------------------------------------------------------------------------------
2-Year 0.113 2-Year 0.000
5-Year 0.184 5-Year 0.000
10-Year 0.248 10-Year 0.000
25-Year 0.314 25-Year 0.000
50-Year 0.401 50-Year 0.000
100-Year 0.435 100-Year 0.000
200-Year 0.677 200-Year 0.179
500-Year 1.002 500-Year 0.420
** Record too Short to Compute Peak Discharge for These Recurrence Intervals
STORM FLOW CONTROL - INFILTRATION SIZING CALCULATIONS
CMP Detention System #1
FULLY INFILTRATES
THE 100-YR STORMP R E L I M I N A R Y
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.54
Program License Number: 201910001
Project Simulation Performed on: 08/10/2021 9:45 AM
Report Generation Date: 08/10/2021 9:45 AM
—————————————————————————————————
Input File Name: 2021-08-03 OLVK8 Detention Cals_Infiltration_Small Pipes.fld
Project Name: OVES K8 Redevelopment
Analysis Title: Basin B Detention Sizing Design w/ Infiltration (7.5"/hr)
Comments: Field is underdrained and 100% Impervious
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 15
Extended Precipitation Time Series Selected
Climatic Region Number: 15
Full Period of Record Available used for Routing
Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961040 Puget East 40 in MAP
Evaporation Scale Factor : 0.750
HSPF Parameter Region Number: 1
HSPF Parameter Region Name : USGS Default
********** Default HSPF Parameters Used (Not Modified by User) ***************
********************** WATERSHED DEFINITION ***********************
Predevelopment/Post Development Tributary Area Summary
Predeveloped Post Developed
Total Subbasin Area (acres) 1.487 1.487
Area of Links that Include Precip/Evap (acres) 0.000 0.000
Total (acres) 1.487 1.487
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Forest 1.487
----------------------------------------------
Subbasin Total 1.487
P R E L I M I N A R YSTORM FLOW CONTROL - INFILTRATION SIZING CALCULATIONS
CMP Detention System #2
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Grass 0.418
Impervious 1.069
----------------------------------------------
Subbasin Total 1.487
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
------------------------------------------
Link Name: Detention Vault
Link Type: Structure
Downstream Link: None
Prismatic Pond Option Used
Pond Floor Elevation (ft) : 278.70
Riser Crest Elevation (ft) : 285.70
Max Pond Elevation (ft) : 286.20
Storage Depth (ft) : 7.00
Pond Bottom Length (ft) : 35.8
Pond Bottom Width (ft) : 24.0
Pond Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00
Bottom Area (sq-ft) : 858.
Area at Riser Crest El (sq-ft) : 858.
(acres) : 0.020
Volume at Riser Crest (cu-ft) : 6,006.
(ac-ft) : 0.138
Area at Max Elevation (sq-ft) : 858.
(acres) : 0.020
Vol at Max Elevation (cu-ft) : 6,435.
(ac-ft) : 0.148
Constant Infiltration Option Used
Infiltration Rate (in/hr): 7.50
Riser Geometry
Riser Structure Type : Circular
Riser Diameter (in) : 12.00
Common Length (ft) : 0.000
Riser Crest Elevation : 285.70 ft
INCLUDES 6-INCHES SEDIMENT STORAGE
& 6-INCHES FREEBOARDP R E L I M I N A R YSTORM FLOW CONTROL - INFILTRATION SIZING CALCULATIONS
CMP Detention System #2
Hydraulic Structure Geometry
Number of Devices: 0
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
Number of Links: 1
********** Link: Detention Vault ********** Link WSEL
Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) WSEL Peak (ft)
======================================
1.05-Year 279.093
1.11-Year 279.279
1.25-Year 279.382
2.00-Year 279.962
3.33-Year 280.478
5-Year 281.082
10-Year 282.136
25-Year 283.770
50-Year 284.867
100-Year 285.635
***********Groundwater Recharge Summary *************
Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures
Total Predeveloped Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 256.402
_____________________________________
Total: 256.402
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 51.084
Link: Detention Vault 563.345
_____________________________________
Total: 614.429
Total Predevelopment Recharge is Less than Post Developed
STORM FLOW CONTROL - INFILTRATION SIZING CALCULATIONS
CMP Detention System #2
EMERGENCY OVERFLOW ELEVATION
P R E L I M I N A R Y
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 1.623 ac-ft/year, Post Developed: 3.889 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
********** Link: Detention Vault **********
Basic Wet Pond Volume (91% Exceedance): 5160. cu-ft
Computed Large Wet Pond Volume, 1.5*Basic Volume: 7741. cu-ft
Time to Infiltrate 91% Treatment Volume, (Hours): 9.62
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 563.35
Inflow Volume Including PPT-Evap (ac-ft): 563.35
Total Runoff Infiltrated (ac-ft): 563.35, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
***********Compliance Point Results *************
Scenario Predeveloped Compliance Subbasin: Subbasin 1
Scenario Postdeveloped Compliance Link: Detention Vault
*** Point of Compliance Flow Frequency Data ***
Recurrence Interval Computed Using Gringorten Plotting Position
Predevelopment Runoff Postdevelopment Runoff
Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs)
----------------------------------------------------------------------------------------------------------------------
2-Year 3.169E-02 2-Year 0.000
5-Year 5.164E-02 5-Year 0.000
10-Year 6.958E-02 10-Year 0.000
25-Year 8.823E-02 25-Year 0.000
50-Year 0.113 50-Year 0.000
100-Year 0.122 100-Year 0.000
200-Year 0.190 200-Year 4.594E-02
500-Year 0.281 500-Year 0.108
** Record too Short to Compute Peak Discharge for These Recurrence Intervals
STORM FLOW CONTROL - INFILTRATION SIZING CALCULATIONS
CMP Detention System #2
FULLY INFILTRATES
THE 100-YR STORMP R E L I M I N A R Y
Proposed Runoff Conditions for TESC - Entire Site
Total Site:Area (ac)
Pervious Area 0.000
Impervious Area 6.900
Total Area 6.900
Stormshed
Data Type Reduced
Time Step 15-min
MGS - Flood 2-Yr developed flow 2.534 cfs
MGS - Flood 10-Yr developed flow 3.703 cfs
MGS - Flood 25-Yr developed flow 4.661 cfs
MGS - Flood 100-Yr developed flow 6.860 cfs
Vr=S.A. x 3.5'Vr = Minimum Required Storage Volume
S.A. = Minimum allowable top surface area of pond
S.A. = (2Q2)/Vsed
Q = design peak flow rate
Vsed = 0.00096 Settling Velocity (0.00096 ft/sec)
Q=3.703 cfs INPUT (note that this is the 10-yr design peak flow rate in cfs)
S.A. = 7715 sf (Top Surface Area of Pond w/ 3:1 side slopes)
Vr=27001 cf Volume Required
201,982 gal
* the volume is based a minimum pond depth of 3.5' - this depth does not
include the minimum sediment storage volume or freeboard
Temporary Sediment Pond Sizing: Storage Volume per Section D.2.1.5, ESC Measures: Selection of the Design Storm
of the 2016 King County Surface Water Design Manual - Appendix D:
255 S. King Street, Suite 800, Seattle, WA 98104 | 206.426.2600 | JACOBSONENGINEERS.COMP R E L I M I N A R Y
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.54
Program License Number: 201910001
Project Simulation Performed on: 02/16/2021 9:27 AM
Report Generation Date: 02/16/2021 9:27 AM
—————————————————————————————————
Input File Name: OLVK8_TESC.fld
Project Name: OVES K8 Redevelopment
Analysis Title: TESC Sediment Tank Sizing
Comments:
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 15
Extended Precipitation Time Series Selected
Climatic Region Number: 15
Full Period of Record Available used for Routing
Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961040 Puget East 40 in MAP
Evaporation Scale Factor : 0.750
HSPF Parameter Region Number: 1
HSPF Parameter Region Name : USGS Default
********** Default HSPF Parameters Used (Not Modified by User) ***************
********************** WATERSHED DEFINITION ***********************
Predevelopment/Post Development Tributary Area Summary
Predeveloped Post Developed
Total Subbasin Area (acres) 6.800 6.800
Area of Links that Include Precip/Evap (acres) 0.000 0.000
Total (acres) 6.800 6.800
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Predeveloped ----------
-------Area (Acres) --------
Till Forest 6.800
----------------------------------------------
Subbasin Total 6.800
P R E L I M I N A R YTESC - SEDIMENTATION POND SIZING CALCULATIONS
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Post Developed ----------
-------Area (Acres) --------
Impervious 6.800
----------------------------------------------
Subbasin Total 6.800
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
------------------------------------------
Link Name: Outflow
Link Type: Copy
Downstream Link: None
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
Number of Links: 1
***********Groundwater Recharge Summary *************
Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures
Total Predeveloped Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Predeveloped 1172.517
_____________________________________
Total: 1172.517
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Post Developed 0.000 P R E L I M I N A R YTESC - SEDIMENTATION POND SIZING CALCULATIONS
Link: Outflow 0.000
_____________________________________
Total: 0.000
Total Predevelopment Recharge is Greater than Post Developed
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 7.421 ac-ft/year, Post Developed: 0.000 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
********** Link: Outflow **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 3048.77
Inflow Volume Including PPT-Evap (ac-ft): 3048.77
Total Runoff Infiltrated (ac-ft): 0.00, 0.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 3048.77
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00%
***********Compliance Point Results *************
Scenario Predeveloped Compliance Subbasin: Predeveloped
Scenario Postdeveloped Compliance Link: Outflow
*** Point of Compliance Flow Frequency Data ***
Recurrence Interval Computed Using Gringorten Plotting Position
Predevelopment Runoff Postdevelopment Runoff
Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs)
----------------------------------------------------------------------------------------------------------------------
2-Year 0.145 2-Year 2.534
5-Year 0.236 5-Year 3.292
10-Year 0.318 10-Year 3.703
25-Year 0.403 25-Year 4.661
50-Year 0.515 50-Year 5.933
100-Year 0.558 100-Year 6.860
200-Year 0.868 200-Year 7.111
500-Year 1.286 500-Year 7.442
** Record too Short to Compute Peak Discharge for These Recurrence Intervals
P R E L I M I N A R YTESC - SEDIMENTATION POND SIZING CALCULATIONS
21
Appendix B
AESI “SUBSURFACE EXPLORATION, GEOLOGIC HAZARD,
INFILTRATION DESIGN, AND GEOTECHNICAL ENGINEERING
REPORT”
associated
earth sciences
incorporated
Associated Earth Sciences, Inc.
911 5th Avenue
Kirkland, WA 98033
P (425) 827 7701
Subsurface Exploration, Geologic Hazard, Infiltration Design,
and Geotechnical Engineering Report
OLYMPIC VIEW K-8 SCHOOL
Federal Way, Washington
Prepared For:
FEDERAL WAY SCHOOL DISTRICT NO. 210
Project No. 20200286E001
March 30, 2021
Kirkland | Tacoma | Mount Vernon
425-827-7701 | www.aesgeo.com
March 30, 2021
Project No. 20200286E001
Federal Way School District No. 210
1211 South 332nd Street
Federal Way, Washington 98003
Attention: Mr. Mike Kwaske
Subject: Subsurface Exploration, Geologic Hazard, Infiltration Design
and Geotechnical Engineering Report
Olympic View K-8 School
2626 SW 327th Street
Federal Way, Washington
Dear Mr. Kwaske:
We are pleased to present the enclosed copy of the referenced report. This report summarizes
the results of tasks including subsurface exploration, geologic hazard analysis, laboratory testing,
infiltration rate testing, stormwater infiltration design recommendations, and geotechnical
engineering, and offers recommendations for design of the project. This report is based on
project plans that were current at the time it was written. If plans change substantially, we should
be allowed to review our recommendations and revise them as needed. This report supersedes
our preliminary report sent out on November 4, 2020.
We have enjoyed working with you on this study and are confident that the recommendations
presented in this report will aid in the successful completion of your project. Please contact me
if you have any questions or if we can be of additional help to you.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
______________________________
Kurt D. Merriman, P.E.
Senior Principal Engineer
KDM/ld - 20200286E001-4
SUBSURFACE EXPLORATION, GEOLOGIC HAZARD,
INFILTRATION DESIGN, AND
GEOTECHNICAL ENGINEERING REPORT
OLYMPIC VIEW K-8 SCHOOL
Federal Way, Washington
Prepared for:
Federal Way School District No. 210
1211 South 332nd Street
Federal Way, Washington 98003
Prepared by:
Associated Earth Sciences, Inc.
911 5th Avenue
Kirkland, Washington 98033
425-827-7701
March 30, 2021
Project No. 20200286E001
Subsurface Exploration, Geologic Hazard, Infiltration Design,
Olympic View K-8 School and Geotechnical Engineering Report
Federal Way, Washington Project and Site Conditions
March 30, 2021 ASSOCIATED EARTH SCIENCES, INC.
ART/ld - 20200286E001-4 Page 1
I. PROJECT AND SITE CONDITIONS
1.0 INTRODUCTION
This report presents the results of Associated Earth Sciences, Inc.’s (AESI’s) subsurface
exploration, geologic hazard analysis, geotechnical engineering, and stormwater infiltration
design study for the proposed demolition and replacement of the existing Olympic View K-8
School in Federal Way, Washington. The site location is shown on the “Vicinity Map,” Figure 1.
The approximate locations of explorations completed for this study are shown on the “Site and
Exploration Plan,” Figure 2. The approximate locations of explorations in relation to the proposed
construction can be found on the “Proposed Site and Exploration Plan,” Figure 3. The location of
the site in relation to groundwater supply wells is shown on the map of “Critical Aquifer Recharge
Areas,” Figure 4. Logs of our subsurface explorations are included in Appendix A. Laboratory
testing is included in Appendix B. Infiltration test data sheets are included in Appendix C.
1.1 Purpose and Scope
The purpose of this study is to provide subsurface soil and groundwater data to be utilized in the
design of the Olympic View K-8 School replacement project. Our study included reviewing
selected available geologic literature, advancing nineteen exploration borings (EB-1 through
EB-19), excavating two exploration pits (EP-1 and EP-2), conducting five infiltration rate tests (IT-1
through IT-5), installing one groundwater observation well, completing laboratory testing of soil
grain-size distribution, and performing a geologic study of subsurface sediment and groundwater
conditions. Geotechnical engineering studies were completed to formulate recommendations for
the type of suitable foundations, allowable foundation soil bearing pressures, anticipated
foundation settlements, erosion considerations, and general site drainage. The stormwater
infiltration part of our study is intended to support design of the infiltration facilities included on
civil engineering plans. This report summarizes our current fieldwork and offers design
recommendations based on our present understanding of the project.
1.2 Authorization
Authorization to proceed with this study was given to AESI by means of District Purchase Order
21000138 dated February 16, 2021. Our study was accomplished in general accordance with our
proposal dated January 14, 2021. This report has been prepared for the exclusive use of
Federal Way School District (District) and its agents, for specific application to this project. Within
the limitations of scope, schedule, and budget, our services have been performed in accordance
with generally accepted geotechnical engineering and engineering geology practices in effect in
this area at the time our report was prepared. No other warranty, express or implied, is made.
Subsurface Exploration, Geologic Hazard, Infiltration Design,
Olympic View K-8 School and Geotechnical Engineering Report
Federal Way, Washington Project and Site Conditions
March 30, 2021 ASSOCIATED EARTH SCIENCES, INC.
ART/ld - 20200286E001-4 Page 2
2.0 PROJECT AND SITE DESCRIPTION
The project site is that of the existing Olympic View K-8 School. The existing school was
constructed in 1963. The existing school buildings are situated on the south-central part of the
site, with paved parking areas to the east and south, paved and natural turf play areas to the
north, and a bus drop-off lane to the south. Twin Lakes Golf and Country Club is adjacent offsite
to the southwest. On-site topography is relatively flat where the existing buildings and playfields
are located, with vertical relief of less than about 5 feet. At the north and southwest edges of the
site, slopes descend from the developed portion of the site to the property boundary. In both
locations existing slopes are approximately 20 to 30 feet tall. The existing slopes are not mapped
as critical areas on the City of Federal Way Critical Areas Map dated May 2016. The slopes do not
appear to meet the definition for Landslide Hazard Areas as defined in Federal Way Municipal
Code (FWMC) Section 19.05.070.
The project will include demolition of the existing school and construction of a new K-8 school.
The new facility will be constructed close to existing grades without deep excavations or thick fill
placement. The new building will be supported on conventional shallow foundations underlain
by a ground improvement system consisting of aggregate piers. The project will include
infiltration facilities north, east, and south of the new building as shown on Figure 3.
2.1 Historical Geotechnical Work
AESI previously completed geotechnical engineering tasks for the District on the Olympic View
Elementary School campus in 1998 and 2000.
In 1998, we completed a limited investigation of an area of floor slab settlement and cracking.
That study relied, in part, on a geotechnical report prepared in the 1960’s by another consultant
during design of the school that now exists. The older geotechnical report was not retained in
our 1998 project archives but was summarized in our 1998 report. The older geotechnical report
concluded that the project site was underlain in 1960 by approximately 10 feet of man-placed
fill, which is consistent with the published geologic map discussed later in this report that depicts
the site as being underlain at shallow depths by modified land. The report prepared by AESI in
1998 concluded that settlement of existing fill placed prior to the 1960’s likely caused or
contributed to the structural settlement investigated in 1998.
In 2000, AESI performed a limited geotechnical investigation and made recommendations for
repair of failing pavement and expansion of the bus lane. Two shallow hand explorations
completed in the south parking lot encountered materials interpreted as weathered lodgement
till sediments at shallow depths.
Subsurface Exploration, Geologic Hazard, Infiltration Design,
Olympic View K-8 School and Geotechnical Engineering Report
Federal Way, Washington Project and Site Conditions
March 30, 2021 ASSOCIATED EARTH SCIENCES, INC.
ART/ld - 20200286E001-4 Page 3
3.0 SITE EXPLORATION
Our field investigations for the current study were conducted in October 2020 and March 2021.
It included advancing nineteen exploration borings, with one of the explorations completed as a
groundwater observation well. Along with the borings, we completed five infiltration rate tests
and excavated two exploration pits. The locations of subsurface explorations referenced in this
study are presented relative to existing and proposed site development on Figure 2 and Figure 3.
The various types of sediments, as well as the depths where the characteristics of the sediments
changed, are indicated on the exploration logs presented in Appendix A. The depths indicated on
the logs where conditions changed may represent gradational variations between sediment
types. If changes occurred between sample intervals in our exploration borings, they were
interpreted. Our explorations were approximately located in the field by measuring from known
site features depicted on the aerial photograph used as a basis for Figure 2.
The conclusions and recommendations presented in this report are based, in part, on the
explorations completed for this study. The number, locations, and depths of the explorations
were completed within site and budgetary constraints. Because of the nature of exploratory work
below ground, extrapolation of subsurface conditions between field explorations is necessary.
It should be noted that differing subsurface conditions may be present due to the random nature
of deposition and the alteration of topography by past grading and/or filling. The nature and
extent of variations between the field explorations may not become fully evident until
construction. If variations are observed at that time, it may be necessary to re-evaluate specific
recommendations in this report and make appropriate changes.
3.1 Exploration Borings
For this study, exploration borings were completed by advancing an 8-inch, outside-diameter,
hollow-stem auger using a track-mounted drill. During the drilling process, samples were
generally obtained at 2½- to 5-foot-depth intervals. The borings were continuously observed and
logged by a geologist from our firm. The exploration logs presented in Appendix A are based on
the field logs, drilling action, visual observation of the samples collected, and laboratory
grain-size testing data included in this report.
Disturbed, but representative samples were obtained by using the Standard Penetration Test
(SPT) procedure in accordance with ASTM International (ASTM) D-1586. This test and sampling
method consists of driving a standard 2-inch, outside-diameter, split-barrel sampler a distance of
18 inches into the soil with a 140-pound hammer free-falling a distance of 30 inches. The number
of blows for each 6-inch interval is recorded, and the number of blows required to drive the
sampler the final 12 inches is known as the Standard Penetration Resistance (“N”) or blow count.
If a total of 50 is recorded within one 6-inch interval, the blow count is recorded as the number
of blows for the corresponding number of inches of penetration. The resistance, or N-value,
Subsurface Exploration, Geologic Hazard, Infiltration Design,
Olympic View K-8 School and Geotechnical Engineering Report
Federal Way, Washington Project and Site Conditions
March 30, 2021 ASSOCIATED EARTH SCIENCES, INC.
ART/ld - 20200286E001-4 Page 4
provides a measure of the relative density of granular soils or the relative consistency of cohesive
soils; these values are plotted on the attached exploration boring logs.
The samples obtained from the split-barrel sampler were classified in the field and representative
portions placed in watertight containers. The samples were then transported to our laboratory
for further visual classification and laboratory testing.
3.2 Groundwater Observation Well
One groundwater observation well was installed in EB-2W. This well consists of a 2-inch-diameter
polyvinyl chloride (PVC) Schedule-40 well casing with threaded connections, the lower 10 feet of
which is finely slotted (0.010-inch machine slot) well screen to allow water inflow. The annular
space around the well screen was backfilled with clean sand, and the upper portion of annulus
was sealed with bentonite chips and concrete. A flush-mounted steel monument was placed over
the top of the wellhead for protection. The as-built configuration of the well is illustrated on the
boring log in Appendix A. Within a week after installation, an AESI representative developed the
well by adding several well volumes of water. The well was sounded most recently on March 2,
2021 and it was observed to remain dry.
3.3 Infiltration and Exploration Pits
For this study, the five infiltration rate tests and two exploration pits were completed by using a
Caterpillar 312 Trackhoe with steel tracks and a 36-inch-wide bucket. The infiltration test
excavations and test pits allow direct observation of in situ subsurface conditions. The infiltration
test excavations and exploration pits were continuously observed and logged by a geologist from
our firm. The exploration logs presented in Appendix A are based on the field logs, digging action,
visual observation of the samples collected, and laboratory grain-size testing data included in this
report. Each pit was generally taken to a maximum depth allowed by the trackhoe, about
18.5 feet. More information about the infiltration testing can be found below in Sections 5.0 and
17.0.
The samples obtained from exploration pits were classified in the field and representative
portions placed in watertight containers. The samples were then transported to our laboratory
for further visual classification and laboratory testing.
Subsurface Exploration, Geologic Hazard, Infiltration Design,
Olympic View K-8 School and Geotechnical Engineering Report
Federal Way, Washington Project and Site Conditions
March 30, 2021 ASSOCIATED EARTH SCIENCES, INC.
ART/ld - 20200286E001-4 Page 5
4.0 SUBSURFACE CONDITIONS
4.1 Regional Geologic Map and Information by Others
Published geologic mapping for the site and immediate vicinity were reviewed on the United
States Geological Survey National Geologic Map Database1 , and on the Washington State
Department of Natural Resources (DNR) Geologic Information Portal 2. These published regional
geologic maps indicate that the site is underlain at shallow depths by modified land created
during previous earthwork onsite. Vashon ice-contact sediments are mapped adjacent to the
north of the site, Vashon lodgement till is mapped adjacent to the east and south, and Vashon
advance outwash is mapped to the west. Published mapping suggests that the depth from the
existing ground surface onsite to the base of the advance outwash is on the order of 60 feet. This
estimated depth to the base of advance outwash can be important for stormwater infiltration
feasibility, and is generally consistent with our interpretation of the sediments encountered in
explorations for this study.
4.2 Site Stratigraphy
Subsurface conditions at the project site were inferred from the field explorations accomplished
for this study, visual reconnaissance of the site, and review of selected applicable geologic
literature. As shown on the exploration logs, soils encountered at the site consisted of fill of
variable thickness overlying native sediments interpreted as Vashon advance outwash. Thin
layers of native sediments interpreted as lodgement till were observed in three explorations
between surficial fill and underlying advance outwash. The following sections present more
detailed subsurface information on the sediment types encountered at the site.
Topsoil and Existing Asphalt
Organic-rich brown topsoil and grass were encountered at the ground surface in all borings and
pits except EB-4, EB-9, EB-17, and EB-18 which were drilled through existing asphalt paving. The
observed depths of topsoil ranged between 6 and 12 inches at the boring locations and are shown
on the exploration logs. Where observed, the existing asphalt paving was 2 to 3 inches thick.
Fill
Fill soils (those not naturally placed), were encountered in all of our explorations with observed
depths ranging from 3 to approximately 22.5 feet below the existing ground surface. Fill depth at
three boring locations exceeded the depth drilled. Figure 2 of this report includes the observed
1 https://ngmdb.usgs.gov/ngmdb/ngmdb_home.html
2 https://www.dnr.wa.gov/geologyportal
Subsurface Exploration, Geologic Hazard, Infiltration Design,
Olympic View K-8 School and Geotechnical Engineering Report
Federal Way, Washington Project and Site Conditions
March 30, 2021 ASSOCIATED EARTH SCIENCES, INC.
ART/ld - 20200286E001-4 Page 6
fill depths at each of the exploration locations. The fill generally consisted of medium dense to
very dense, moist, brown, fine to medium sand with variable silt content and variable gravel
content. Looser fill with organic content was encountered in exploration borings EB-5 and EB-7
at depths ranging between 8 and 15 feet below existing ground surface. Existing fill is not
recommended for foundation support and may require remedial preparation below new paving.
Excavated existing fill material is suitable for reuse in structural fill applications if such reuse is
specifically allowed by project plans and specifications, if excessively organic and any other
deleterious materials are removed, and if moisture content is adjusted to allow compaction to
the specified level and to a firm and unyielding condition. Existing fill is not suitable for use as an
infiltration receptor for stormwater.
Vashon Lodgement Till
Stratigraphically underlying the fill, three of our exploration pits (EP-2, IT-3, and IT-5)
encountered a typically dense to very dense, unsorted fine, silty, sand with varying amounts of
gravel interpreted as Vashon lodgement till. Lodgement till was deposited at the base of an active
continental glacier and was compacted by the weight of the overlying glacial ice. Undisturbed
medium dense to very dense lodgement till sediments are suitable for foundation support. Due
to the high percentage of fine-grained material present in these sediments, they are susceptible
to disturbance when wet. Reuse of lodgement till in structural fill applications is feasible if
allowed by project specifications, and will require drying to achieve moisture contents within
1 to 2 percent of optimum for compaction purposes. Careful management of moisture-sensitive
soils will be needed to reduce the potential for disturbance of wet till and costs associated with
repairing saturated subgrades. Lodgement till is not suitable for use as an infiltration receptor for
stormwater.
Vashon Advance Outwash
Stratigraphically underlying the fill and lodgement till, sixteen of our exploration borings and all
of our exploration pits encountered typically dense to very dense, stratified sand with varying
amounts of silt and gravel interpreted as Vashon advance outwash. The observed depth to
advance outwash sediments ranged from 6.5 to approximately 22.5 feet below the existing
ground surface. Three borings did not penetrate deep enough to reach advance outwash
sediments. We anticipate that advance outwash sediments are present below the entire site, and
that explorations that did not encounter advance outwash were terminated at depths too
shallow to reach the advance outwash. Advance outwash was deposited by meltwater streams
from an advancing ice sheet and was glacially overridden and compacted. Advance outwash is
suitable for support of aggregate piers, and for direct support of structural loads when prepared
as recommended in this report. Advance outwash may contain a significant fine-grained fraction,
and may be sensitive to excess moisture during placement in structural fill applications. Due to
the depth below existing grade where it was encountered, advance outwash is unlikely to be
Subsurface Exploration, Geologic Hazard, Infiltration Design,
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handled in substantial quantities during construction of the proposed project. Reuse of advance
outwash in structural fill applications is feasible if allowed by project specifications, and will
require drying to achieve moisture contents within 1 to 2 percent of optimum for compaction
purposes. Advance outwash is suitable for use as an infiltration receptor for stormwater, and
infiltration system design recommendations are presented later in this report.
4.3 Hydrology
Groundwater was not encountered in any of the explorations for this study at the time they were
completed (October 2020 and March 2021). Perched groundwater was not observed, but is
possible during the wetter winter months within existing fill, above lodgement till or within the
Vashon advance outwash above localized silty interbeds. Perched water occurs when surface
water infiltrates down through relatively permeable soils, such as existing fill or coarser-grained
advance outwash strata, and becomes trapped or “perched” atop a comparatively
low-permeability barrier, such as lodgement till or silty interbeds within the fill or advance
outwash. When water becomes perched within fill, it may travel laterally and may follow flow
paths related to permeable zones that may not correspond to ground surface topography.
The presence and quantity of groundwater will largely depend on the soil grain-size distribution,
topography, seasonal precipitation, site use, on- and off-site land usage, and other factors.
A groundwater observation well was installed at EB-2W and was screened within the Vashon
advance outwash sediments between 65 and 75 feet below existing ground surface. The well will
be used to monitor groundwater fluctuations throughout the next year. The well was dry when
it was installed, and is useful to demonstrate a substantial interval of unsaturated advance
outwash below future stormwater infiltration facilities. The most recent measurement was taken
on March 2, 2021 and the well was observed to remain dry.
Regional hydrogeology is discussed in Section 9.0 “Critical Aquifer Recharge Areas.”
4.4 Laboratory Testing
Grain-Size Analysis
AESI performed 17 grain-size analyses (sieves) on representative samples of fill and Vashon
advance outwash sediments. The grain-size analyses test results are included in Appendix B.
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5.0 INFILTRATION TESTING AND METHODS
Infiltration testing was conducted in the Vashon advance outwash at the site to evaluate the
suitability of the natural on-site sediments for stormwater infiltration. Testing was completed in
accordance with the Pilot Infiltration Test (PIT) procedure as described in the 2016 King County
Surface Water Design Manual (KCSWDM). The infiltration testing procedure consists of
excavating a flat-bottomed pit with an area of at least 12 square feet. The base of the pit
extended into the intended receptor soil stratum by at least 2 feet. The “constant-head” portion
of the test is then conducted by discharging water into the pit for a “soaking period” of at least
6 hours to allow the receptor soils in the immediate vicinity of the pit to become saturated. After
completion of the soaking period, water continues to be discharged into the pit at a rate sufficient
to maintain a fairly consistent head over a period of at least 1 hour. The final “falling-head”
portion of the test consists of monitoring the rate of head decline in the pit after the discharge
of water into the pit is stopped.
The civil engineering plans provided to AESI outline three proposed infiltration facilities as well
as a possible alternate facility in the existing grass field on the north part of the site. It was
necessary to offset tests IT-1 through IT-5 from proposed infiltration facility locations due to
existing utilities and buildings which were in service at the time of testing. The infiltration tests
were offset up to approximately 50 feet in plan view from the proposed infiltration facility
locations.
Infiltration testing for this study included test locations IT-1 through IT-5. Infiltration testing was
conducted in the dense, un-weathered Vashon advance outwash. Infiltration test details are
summarized in Table 1. Following completion of infiltration testing, the infiltration test pits were
excavated below the tested depth to observe underlying soil conditions. Vashon advance
outwash sediments were encountered to the total depth explored at each infiltration test
location. Post-test seepage was observed in IT-2 and IT-3, above fine-grained layers at depths
greater than the infiltration testing depth. No post-test seepage was observed in IT-1, IT-4, and
IT-5.
Exploration boring data included with this report show that the Vashon advance outwash
sediments are present to at least 45 feet below ground surface at proposed infiltration locations.
At the location of EB-2W Vashon advance outwash extended to greater than 76.5 feet and was
unsaturated.
The following table summarizes the field infiltration test results. Section 17.0 of this report
presents recommended design infiltration rates that incorporate required reduction factors.
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Table 1
Summary of Infiltration Testing
Test No.
and Depth
Surface Area
(square feet)
Discharge
Time
(minutes)
Total Volume
Discharged
(gallons)
Constant-Head
Level (feet)
During Last
Hour
Unfactored Field Infiltration
Rates*
Constant-Head
Test
(in/hr)
Falling-Head
Test
(in/hr)
IT-1 at
10 feet 26.5 420 1,243 1.04 12.0 12.0
IT-2 at
9 feet 22.0 420 4,071 0.92 42.3 44.2
IT-3 at
14 feet 22.0 420 572 0.89 4.3 4.6
IT-4 at
11 feet 21.5 420 2,285 1.03 22.4 25.6
IT-5 at
11 feet 19.5 420 1,731 0.90 21.6 24.9
in/hr = inches per hour
*Field infiltration rates must be reduced for design to account for site variability and test method, clogging, and
groundwater mounding.
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II. GEOLOGIC HAZARDS AND MITIGATIONS
We reviewed mapped geologic hazards on the City of Federal Way Critical Areas Map 1 and King
County iMap2, and the previously referenced DNR map. The reviewed maps do not indicate the
presence of regulated critical slopes, liquefaction areas, or erosion hazard areas on or
immediately adjacent to the project.
The DNR map shows an inferred tectonic fault trace in close proximity to the northeast corner of
the site which is discussed in further detail below.
6.0 LANDSLIDE HAZARDS AND MITIGATIONS
The topography for most of the site is relatively flat to gently sloping. We reviewed topographic
contours presented on Figure 2. A fill slope with inclinations of 20 to 30 percent is present on the
western portion of the site. A fill slope with inclinations of 20 to 25 percent is present on the
northeastern portion of the site. Based on visual reconnaissance of the site, the existing slopes
(west, north, and northeast) appear to have performed well, with no visual indication of unusual
erosion or slope instability. No emergent seepage was observed on the slopes during our site
visit. Based on the relatively uniform inclinations, the slopes appear to have resulted from
previous grading. Given the subsurface conditions on the site and the inclination and height of
the slopes, it is our opinion that the risk of damage to the proposed improvements by landslide
activity on these slopes under both static and seismic conditions is low. No detailed quantitative
assessment of slope stability was completed as part of this study, and none is warranted to
support the project as currently proposed, in our opinion.
7.0 SEISMIC HAZARDS AND MITIGATIONS
The site does not include areas designated as Seismic Hazard Areas on the previously-referenced
City of Federal Way Critical Areas Map. The following discussion is a more general assessment of
seismic hazards that is intended to be useful to the project design team in terms of understanding
seismic issues, and to the structural engineer for structural design.
Earthquakes occur regularly in the Puget Lowland. The majority of these events are small and are
usually not felt by people. However, large earthquakes do occur, as evidenced by the 1949,
7.2-magnitude event; the 1965, 6.5-magnitude event; and the 2001, 6.8-magnitude event.
1 https://www.cityoffederalway.com/sites/default/files/maps/sensitive_2016.pdf
2 https://gismaps.kingcounty.gov/iMap/
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The 1949 earthquake appears to have been the largest in this region during recorded history and
was centered in the Olympia area. Evaluation of earthquake return rates indicates that an
earthquake of the magnitude between 5.5 and 6.0 is likely within a given 20-year period.
Generally, there are three types of potential geologic hazards associated with large seismic
events: 1) surficial ground rupture, 2) liquefaction, and 3) ground motion. The potential for each
of these hazards to adversely impact the proposed project is discussed below.
7.1 Surficial Ground Rupture
Generally, the largest earthquakes that have occurred in the Puget Sound area are sub-crustal
events with epicenters ranging from 50 to 70 kilometers in depth. Earthquakes that are
generated at such depths usually do not result in fault rupture at the ground surface. Current
research indicates that surficial ground rupture is possible in areas close to the Tacoma Fault
Zone (TFZ), the closest mapped fault zone to the project.
The site is located in the TFZ. The TFZ is a zone of interrelated fault traces that runs approximately
east to west in plan view and is several miles in width north to south. The TFZ is geologically active
and capable of generating surface rupture during a seismic event. Fault traces in the TFZ are
obscured at the ground surface by geologically young glacial sediments and by modification of
the ground surface by human activities. Approximate locations of fault traces are mapped using
indirect geophysical methods. We reviewed mapped faults on the Washington State DNR
Geologic Map Portal 3. The DNR map shows an inferred tectonic fault trace in close proximity to
the northeast corner of the site. Faults in the project area are inferred from geophysical data,
and if present are covered by thick layers of glacial sediments that make them difficult to locate
precisely. A more detailed investigation of potential tectonic faulting is not included in our
current scope but could be completed on request.
7.2 Liquefaction
Liquefaction is a temporary loss in soil shear strength that can occur when loose granular soils
below the groundwater table are exposed to cyclic accelerations, such as those that occur during
earthquakes. The observed site sediments were observed to be unsaturated and are not
expected to be prone to liquefaction due to their generally high density and absence of shallow
groundwater. A detailed liquefaction hazard analysis was not performed as part of this study, and
none is warranted, in our opinion.
3 https://www.dnr.wa.gov/geologyportal
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7.3 Ground Motion/Seismic Site Class (2018 International Building Code)
Structural design of the new building should follow 2018 International Building Code (IBC)
standards. We recommend that the project be designed in accordance with Site Class “D”
in accordance with the 2018 IBC, and the publication American Society of Civil Engineers (ASCE) 7
referenced therein, the most recent version of which is ASCE 7-16.
8.0 EROSION CONTROL
Project plans should include implementation of temporary erosion controls in accordance with
local standards of practice. Control methods should include limiting earthwork to seasonally drier
periods if possible, use of perimeter silt fences, stabilized construction entrances, and straw
mulch in exposed areas. Removal of existing vegetation should be limited to those areas that are
required to construct the project, and new landscaping and vegetation with equivalent erosion
mitigation potential should be established as soon as practical after grading is complete. During
construction, surface water should be collected as close as possible to the source to minimize silt
entrainment that could require treatment or detention prior to discharge. Timely
implementation of permanent drainage control measures should also be a part of the project
plans, and will help reduce erosion and generation of silty surface water onsite.
9.0 CRITICAL AQUIFER RECHARGE AREAS
The site is within an area identified by the City of Federal Way as a Critical Aquifer Recharge Area
(CARA). The following report sections are intended to satisfy report requirements for
construction proposals within designated CARAs.
9.1 Critical Aquifer Recharge Areas Capture Zones
Critical aquifer recharge areas have prevailing geologic conditions associated with infiltration
rates that create a high potential for contamination of groundwater resources or contribute
significantly to the replenishment of groundwater. The CARAs are classified in part by published
time of travel (TOT) map zones, also referred to as Capture Zones, around individual water supply
wells. The TOT refers to the amount of time it takes water to discharge to a well from its point of
infiltration.
Per FWMC Article V, Chapter 19.145.450: “This article regulates development located within
designated capture zones. Six-month, one-year, five-year, and 10-year capture zones are
designated as critical aquifer recharge areas under the provisions of the Growth Management
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Act (Chapter 36.70A RCW) and are established based on proximity to and travel time of
groundwater to the city’s public water source wells.”
Per FWMC 19.145.460: “As required by WAC 365-196-485 (Critical Areas), the city shall protect
the quality and quantity of groundwater used for public water supplies. The Lakehaven Utility
District (“LUD”) has designated four capture zones based on proximity to and travel time of
groundwater to Group A and Group B public water supplies.” The capture zones include the
following:
(1) Six-month capture zone represents the land area overlaying the six-month time-of-travel zone of any
public water source well owned by LUD.
(2) One-year capture zone represents the land area overlaying the one-year time-of-travel zone of any
public water source well owned by LUD, excluding the land area contained in the six-month capture zone.
(3) Five-year capture zone represents the land area overlaying the five-year time-of-travel zone of any
public water source well owned by LUD, excluding the land area contained in the six-month and one-year
capture zones.
(4) Ten-year capture zone represents the land area overlaying the 10-year time-of-travel zone of any public
water source well owned by LUD, excluding the land area contained in the six-month, one-year, and
five-year capture zones.
9.2 Regional Hydrogeology
Water that exists in the pore spaces of sediments is part of the hydrologic cycle. In the natural
state, the hydrologic cycle begins with infiltration of precipitation (recharge) and ends with
discharge to springs, streams, wetlands, and/or wells. Under natural conditions, groundwater
recharge and discharge may shift with climatic cycles but remain in overall balance. Groundwater
will flow under saturated conditions, preferentially through materials with greater porosity and
permeability, such as clean gravels and sands. Where geologic conditions limit discharge,
groundwater accumulates in such permeable zones, where if sufficient groundwater quantities
are present to supply water to wells, are termed aquifers. The regional hydrogeologic setting in
the site vicinity has been described in three primary reference documents:
• Luzier, J.E., 1969, Geology and ground-water resources of southwestern King County,
Washington: Washington Division of Water Resources, Water-Supply Bulletin 28, scale
1:48,000.
• Cline, D.R., 1969, Availability of ground water in the Federal Way area, King County,
Washington: U.S. Geological Survey, Open-File Report OF-69-44, scale 1:24,000.
• Woodward, D.G., Packard, F.A., Dion, N.P., and Sumioka, S.S., 1995, Occurrence and
quality of ground water in southwestern King County, Washington: U.S. Geological
Survey, Water-Resources Investigations Report 92-4098, scale 1:100,000.
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These reports include descriptions of principal hydrogeologic units, groundwater levels, and flow
directions; largely based on information from water supply well logs, springs, and water pumpage
data.
Building on the previous studies, Woodward et al. (1995) correlated hydrogeologic units to the
stratigraphic units in the site vicinity based on primary grain size and degree of saturation (i.e.,
aquifer or confining unit) and identified four hydrogeologic units relevant to the project, in
addition to interflow: 1) Vashon till was designated Qvt as a confining bed, 2) Vashon advance
outwash was designated Qva as an aquifer, 3) pre-Fraser non-glacial was designated Q(A)f as a
confining bed, and 4) pre-Fraser glacial outwash was designated Q(A)c as an aquifer.
Woodward et al. (1995) indicates that the site is located in area where the Q(A)f confining bed is
absent and Qva aquifer and Q(A)c aquifer are hydraulically connected.
9.3 Groundwater Wells and Use Near the Site
The Washington State Department of Ecology’s (Ecology’s) on-line well log, Washington State
Department of Health’s (DOH’s) on-line source water assessment program (SWAP) was reviewed
to obtain information on water supply wells near the subject property. The site and surrounding
area are served by LUD. No Group A, Group B, or domestic wells are located within a 1/4-mile
radius of the site. However, the site is within the 5- and 10-year TOT of one public water system
well, the LUD well #19A (Figure 4).
The LUD well #19A is summarized in Table 2 and described below.
• The LUD well #19A is located about 2 miles southeast of the site (Figure 4). The DOH and
Ecology well log indicate the well was drilled to 216 feet and screened from 114 to
154 feet and 164 to 184 feet below ground surface. The reported ground surface
elevation and static water level are 283 feet above mean sea level (amsl) and 223 feet,
respectively. Based on the location and depth of the well, the well is interpreted to
produce from the Qva and Q(A)c aquifers. The regional groundwater flow direction is
unknown, and the well is assumed to be located downgradient from the proposed
infiltration system based on Woodward et al. (1995). As indicated above, the site is within
the 5- and 10-year TOT of the well.
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Table 2
Water Supply System Summary
Group Water
Supply Name DOH Water System ID
Reported Well
Depth (feet)
Approximate Well
Production
Elevation (feet) Comment
Lakehaven Water
and Sewer District
41997
Source No. 26
Well #19A
Depth to first open
interval = 114;
Well depth = 184
169 to 99 feet Interpreted to
be screened in
the Qva and
Q(A)c aquifers
DOH Water System ID = Washington State Department of Health Water System Identification Number.
9.4 Impacts and Mitigation
The proposed project will be designed to be protective of groundwater and surface water
resources by treating and retaining/detaining stormwater in compliance with City of Federal Way
stormwater requirements, and incorporating stormwater infiltration to maintain groundwater
recharge. In our opinion, there should be no deleterious impact from the proposed development
on water supply well LUD well #19A because the stormwater will be treated prior to infiltration
and there is greater than 50 feet of unsaturated sediments above the water table to provide
additional filtering/treatment. Groundwater elevations beneath the site are lower about
elevation 212 feet, and lower than groundwater reported for LUD well #19A, indicating that the
site is potentially downgradient from the water supply well. No additional mitigation measures
are required. No detailed CARA analysis was performed for this project, and none is warranted,
in our opinion.
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III. DESIGN RECOMMENDATIONS
10.0 INTRODUCTION
Our explorations indicate that, from a geotechnical engineering standpoint, the proposed project
is feasible provided the recommendations in this report are incorporated into design and
construction of the project. The bearing stratum was observed to vary from 3 to greater than
21 feet below the existing ground surface.
• We recommend that the new building and any other substantial structures be
constructed using a conventional shallow foundation system underlain by ground
improvement consisting of the installation of aggregate piers. Other foundation support
alternatives are possible, including removing and replacing existing fill, installing
foundation piles, or soil cement treatment. We are available to discuss other foundation
support approaches on request.
• Areas of new paving and other similar ancillary structures should be assessed, and some
level of remedial preparation of existing fill may be warranted as outlined in the “Site
Preparation” section of this report.
• Stormwater infiltration for the project is feasible in our opinion. Section 17.0 of this report
presents recommended design infiltration rates applicable to specific locations where
infiltration rate testing was completed.
11.0 SITE PREPARATION
Erosion and surface water control should be established around the perimeter of the excavation
to satisfy City of Federal Way requirements.
11.1 Building Pad Areas
Site preparation should include removal of all existing pavement, structures, buried utilities, and
any other deleterious material from below the new building. Floor support recommendations
contained later in this report require the placement of at least 2 feet of compacted fill below
floor slab areas or, alternatively, cement treatment of existing soils below the planned floor slab
and capillary break as outlined in Section 11.4 of this report. The 2 feet of fill may be achieved
during planned mass grading, or by excavating existing site soils and replacing as needed to
establish the 2 feet of new compacted structural fill. If it is necessary to excavate to achieve 2 feet
of compacted fill below the floor slabs, reuse of excavated soil as structural fill will be
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weather-dependent. Structural fill should be placed in accordance with project specifications and
the “Structural Fill” section of this report. The subgrade for the building pad, or for structural fill
placement below the building pad, is expected to consist of existing fill. The subgrade should be
proof-rolled and compacted. Any areas that are soft, yielding, organic, or otherwise unsuitable
should be repaired as needed based on site observations during construction. Structural fill
should then be placed to reach planned grades. The building pad should be capped with a
working surface of at least 8 inches of crushed rock to facilitate construction of aggregate piers.
11.2 Paving Areas
Areas of planned paving should be prepared by stripping existing vegetation and topsoil,
removing structures and utilities to be demolished, and excavating to planned paving subgrade
elevation. The resulting subgrade should then be evaluated visually, compacted, and
proof-rolled. Exposed soils are expected to consist of existing fill. Areas with organic or
deleterious material, or areas that yield during proof-rolling should receive additional
preparation tailored to proof-rolling results and field conditions at the time of construction.
11.3 Allowance Recommendations
Because building and paving subgrades will consist of existing fill, some amount of remedial
subgrade preparation will likely be needed. We recommend establishing a unit cost in bid
documents for removal and export of unsuitable soils, and import of suitable granular fill. The
unit prices should be based on in situ bank cubic yards as the unit of measurement. An allowance
should be included to encourage competitive unit pricing during bidding. The allowance language
should establish that earthwork allowances are to be used only at the owner’s direction, and in
accordance with unit prices. For planning purposes we recommend including 500 cubic yards of
export/import in bid documents. This is an arbitrary number intended to encourage competitive
pricing, and to allow the owner to budget for anticipated remedial preparation. The actual
amount used may be more or less based on field conditions during construction.
11.4 Soil Cement Treatment
Treatment of weak and/or wet subgrade soils with Portland cement is often a cost-effective way
to establish building pads, paving subgrades, and construction staging areas in areas of existing
fill and weak native sediments.
For this project, the “Site Preparation” section of this report recommends removing and
recompacting the upper 2 feet of existing fill soils below new building pads. In lieu of
recompacting existing soils, the existing fill soils could be left in place and cement-treated. If this
alternative is selected, we recommend:
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• Cement treatment should be completed after installation of aggregate piers.
• The upper 1 foot of existing fill soils below building pads should be cement-treated in
accordance with procedures outlined below.
• If the building pad will be cement-treated, cement treatment should also be considered
in construction staging areas and areas of planned paving.
• Cement-treated areas will be more difficult to excavate for installation of buried utilities
including subfloor Mechanical Electrical and Plumbing (MEP). This project also will use
aggregate piers, which are typically avoided when laying out locations for subfloor
utilities. In this situation the use of dedicated utilidors beneath the building can reduce
conflicts between aggregate piers and subfloor utilities, and reduce the amount of soil-
cement excavation that is required.
• Project bid documents should include notifications to bidders that excavation of
cement-treated soils is anticipated and is part of the base bid to avoid cost claims for extra
work.
Soil-cement treatment consists of applying dry Portland cement powder to the surface of a soil
area that has excess moisture prior to compaction. The cement powder is thoroughly mixed into
the underlying soil to a pre-determined depth. Hydration of the Portland cement consumes the
excess moisture, and allows the soil to be compacted to a firm and unyielding condition. The
amount of cement powder that is required is a function of field moisture content versus
laboratory optimum moisture content for compaction purposes. Typically, the geotechnical
engineer and contractor review field conditions, and estimate an appropriate soil-cement
admixture rate to achieve the desired results. A test pad is then constructed using the estimated
amount of cement powder. Results are evaluated and the cement admixture ratio is fine-tuned
based on initial results. Typical admixture percentages range from about 3 to 7 percent by dry
weight.
On-site soils should be assumed to have a dry weight of 130 pounds per cubic foot (pcf). For
bidding purposes, any place that soil-cement treatment is required, a soil-cement admixture ratio
of 5 percent by dry weight should be used in the base bid. We recommend that the contract
cement treatment base bid quantity also includes a unit cost per cubic yard of treated soil for
application to payments in excess of the base bid, or credits for cement treatment volumes less
than the base bid.
The treated soil should be re-graded and compacted within 4 hours from the start of mixing. Soils
should not be left undisturbed for more than 30 minutes after treatment occurs. Lift thickness
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for compaction purposes should be no greater than 12 inches. In order to determine
effectiveness of the treatment a proof-roll with a fully-loaded dump truck should be conducted
72 hours after the treatment occurs.
Soil-cement areas are typically not durable to vehicle traffic or other intensive uses, particularly
during wet weather, unless very high soil-cement admixture rates are used. The soil-cement
admixture rates recommended in this report are for stabilization of soils with above-optimum
moisture content that will be paved or otherwise protected before they are exposed to vehicles
or other loads. If the soil-cement-treated areas are to be exposed to construction traffic or other
heavy use, they should be protected by a surficial layer of structural fill, by a layer of asphalt
pavement surfacing or asphalt treated base (ATB), or should be completed with a higher cement
admixture percentage. If these situations occur, we should be allowed to offer situation-specific
recommendations.
Soil-cement treatment must be done in such a way that cement dust is controlled during
completion of site work. This is typically accomplished through the use of flexible skirts on
equipment used for application and mixing of the cement powder. Because the skirting and
mixing equipment are specialized equipment, typically specialty contractors are retained for
completion of soil-cement work. In addition to dust control, permitting may require monitoring
of stormwater pH if soil-cement treatment is used. In our experience, typically soil-cement
treated areas have a relatively short initial period of high stormwater pH that rapidly decreases
over time. In the short term, it may be necessary to detain runoff from soil-cement areas and add
dry ice or carbon dioxide diffusers to reduce pH to an acceptable level before discharge offsite.
Typically, pH monitoring requirements will be imposed by either construction or stormwater
permitting. AESI can provide pH monitoring services concurrent with our other construction
observation activities onsite if requested to do so.
11.5 Temporary Cut Slopes
In our opinion, stable construction slopes should be the responsibility of the contractor and
should be determined during construction based on the conditions encountered at that time. For
estimating purposes, however, we anticipate that temporary, unsupported cut slopes in loose to
very dense fill and medium dense to very dense advance outwash sediments be planned at a
maximum slope of 1.5H:1V (Horizontal:Vertical). Steeper temporary slopes in advance outwash
sediments may be feasible if needed depending on site-specific conditions, but may not be
needed for the project as currently proposed. Temporary cut slopes may need to be adjusted in
the field at the time of construction based on the presence of surface water or perched seepage
zones. As is typical with earthwork operations, some sloughing and raveling may occur, and cut
slopes may have to be adjusted in the field. In addition, WISHA/OSHA regulations should be
followed at all times.
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11.6 Site Disturbance
Some of the on-site soils contain a high percentage of fine-grained material, which makes them
moisture-sensitive and subject to disturbance when wet. The contractor must use care during
site preparation and excavation operations so that the underlying soils are not softened,
particularly during wet weather conditions. If disturbance occurs in areas of conventional
footings, the softened soils should be removed and the area brought to grade with clean crushed
rock fill. Because of the moisture-sensitive nature of the soils, we anticipate that wet weather
construction would significantly increase the earthwork costs over dry weather construction.
11.7 Winter Construction
The existing fill material contains substantial silt and is considered highly moisture-sensitive. Soils
excavated onsite will likely require drying during favorable dry weather conditions to allow their
reuse in structural fill applications. During winter conditions use of excavated on-site soils in
compacted fill applications may not be possible, and the use of imported fill or cement treatment
of on-site soils may be needed if sitework will be completed during the winter. Care should be
taken to seal all earthwork areas during mass grading at the end of each workday by grading all
surfaces to drain and sealing them with a smooth-drum roller. Stockpiled soils that will be reused
in structural fill applications should be covered whenever rain is possible.
If winter construction is expected, crushed rock fill should be used to provide construction staging
areas where exposed soil is present. The stripped subgrade should be observed by
the geotechnical engineer, and should then be covered with a geotextile fabric, such as
Mirafi 500X or equivalent. Once the fabric is placed, we recommend using a crushed rock fill layer
at least 10 inches thick in areas where construction equipment will be used. Soil-cement
treatment is another approach to providing a workable site during the winter. We are available
to provide more detailed cement-treatment recommendations on request and if allowed by the
governing jurisdiction.
11.8 Frozen Subgrades
If earthwork takes place during freezing conditions, all exposed subgrades should be allowed to
thaw, and then be re-compacted prior to placing subsequent lifts of structural fill. Alternatively,
the frozen material could be stripped from the subgrade to reveal unfrozen soil prior to placing
subsequent lifts of fill. The frozen soil should not be reused as structural fill until allowed to thaw
and adjusted to the proper moisture content, which may not be possible during winter months.
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12.0 STRUCTURAL FILL
Structural fill should be placed and compacted according to the recommendations presented in
this section and requirements included in project specifications. All references to structural fill in
this report refer to subgrade preparation, fill type, placement, and compaction of materials, as
discussed in this section. If a percentage of compaction is specified under another section of this
report, the value given in that section should be used.
Structural fill is defined as non-organic soil, acceptable to the geotechnical engineer, placed in
maximum 8-inch loose lifts, with each lift being compacted to at least 95 percent of the modified
Proctor maximum dry density using ASTM D-1557 as the standard. In the case of roadway and
utility trench filling, the backfill should be placed and compacted in accordance with City of
Federal Way standards. For planning purposes, we recommend the use of a well-graded sand
and gravel for road and utility trench backfill. At this time we are not aware of any planned
right-of-way work associated with the project.
The contractor should note that AESI should evaluate any proposed fill soils prior to their use in
fills. This would require that we have a sample of the material at least 3 business days in advance
of filling activities to perform a Proctor test and determine its field compaction standard. Soils in
which the amount of fine-grained material (smaller than the No. 200 sieve) is greater than
approximately 5 percent (measured on the minus No. 4 sieve size) should be considered
moisture-sensitive. Use of moisture-sensitive soil in structural fills is not recommended during
the winter months or under wet site and weather conditions. Most of the on-site soils are
moisture-sensitive and have natural moisture contents over optimum for compaction and will
likely require moisture-conditioning before use as structural fill. In addition, construction
equipment traversing the site when the soils are wet can cause considerable disturbance.
If import soil is required, a select import material consisting of a clean, free-draining gravel
and/or sand should be used. Free-draining fill consists of non-organic soil with the amount of
fine-grained material limited to 5 percent by weight when measured on the minus No. 4 sieve
fraction and at least 30 percent retained on the No. 4 sieve.
A representative from our firm should observe the subgrades and be present during placement
of structural fill to observe the work and perform a representative number of in-place density
tests. In this way, the adequacy of the earthwork may be evaluated as filling progresses and any
problem areas may be corrected at that time. It is important to understand that taking random
compaction tests on a part-time basis will not assure uniformity or acceptable performance of a
fill. As such, we are available to aid the owner in developing a suitable monitoring and testing
frequency.
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13.0 FOUNDATIONS
Conventional shallow footings may be used for building support when founded on existing fill
soils improved by placement of aggregate piers, as previously discussed. Figure 3 of this report
includes observed and estimated bearing surface data.
Building foundations should be supported by on-site fill soils improved by construction of
compacted aggregate piers. Building foundations should be designed for an allowable foundation
soil bearing pressure of 5,000 pounds per square foot (psf). This allowable foundation soil bearing
pressure may be increased by one-third to accommodate transient wind and seismic loads.
Perimeter footings should be buried at least 18 inches into the surrounding soil for frost
protection. However, all footings must penetrate to the prescribed bearing stratum, and no
footing should be founded in or above organic or loose soils. All footings should have a minimum
width of 18 inches.
It should be noted that the area bound by lines extending downward at 1H:1V from any footing
must not intersect another footing or intersect a filled area that has not been compacted to
at least 95 percent of ASTM D-1557. In addition, a 1.5H:1V line extending down from any footing
must not daylight because sloughing or raveling may eventually undermine the footing. Thus,
footings should not be placed near the edge of steps or cuts in the bearing soils.
Foundation settlement parameters are established as part of the aggregate pier design process
and are summarized in the following report section. Disturbed soil not removed from footing
excavations prior to footing placement could result in increased settlements. All footing areas
should be inspected by AESI prior to placing concrete to verify that the design bearing capacity
of the soils has been attained and that construction conforms to the recommendations contained
in this report. Such inspections may be required by the governing municipality. Perimeter footing
drains should be provided, as discussed under the “Drainage Considerations” section of this
report.
13.1 Aggregate Piers
Aggregate piers are recommended below the new building and any other substantial structures.
Aggregate piers are vertical columns of compacted stone that are constructed on the building
pad before new foundations are constructed. The purpose of aggregate piers is to both improve
existing fill soils and to transmit loads to more competent native bearing soils at depth. Aggregate
piers are formed by drilling or displacing the existing soil column to a pre-determined depth with
an auger or vibratory mandrel. Crushed rock is fed from the surface and compacted in thin lifts
resulting in a column of compacted aggregate and compaction of soils surrounding the pier.
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Aggregate piers are proprietary systems and are designed by the contractor who installs them.
The contractor will determine the depth and diameter of the pier holes and the appropriate
spacing. Aggregate pier designs are specifically tailored to a foundation plan, and the locations
and depths of foundations should be determined prior to aggregate pier design. Conventional
shallow foundations are then constructed above the subgrade after piers have been installed.
The aggregate pier contractor should review exploration logs contained in this report carefully.
Existing fill soils, such as those observed in our explorations, may contain drilling obstacles.
Where drilling obstacles are encountered, the contractor should be prepared to relocate planned
piers or remove obstacles, as needed, as part of the base bid work.
The aggregate pier design should be based on the following parameters:
Footings:
Maximum Allowable Bearing Pressure for Footings
Supported by Aggregate Piers:
5000 psf
Maximum Total Long-Term Settlement for Footings: ≤ 1 inch
Maximum Long-Term Differential Settlement of Adjacent
Footings:
≤ ½ inch
Maximum Aggregate Pier Spacing Under Foundations: 8 feet
We recommend full-time construction observation by AESI during pier installation to verify that
the piers extend to native bearing soils. Air or water jetting are not acceptable practices during
the installation of aggregate piers.
14.0 DRAINAGE CONSIDERATIONS
Traffic across the on-site soils when they are damp or wet will result in disturbance of the
otherwise firm stratum. Therefore, during sitework and construction, the contractor should
provide surface drainage and subgrade protection, as necessary.
Any retaining walls and all perimeter foundation walls should be provided with a drain at the
footing elevation. Drains should consist of rigid, perforated, PVC pipe surrounded by washed
gravel. The level of the perforations in the pipe should be set at the bottom of the footing, and
the drains should be constructed with sufficient gradient to allow gravity discharge away from
the building. The perforations should be located on the lower portion of the pipe. In addition,
any retaining or subgrade walls should be lined with a minimum, 12-inch-thick, washed gravel
blanket, backfilled completely with free-draining material over the full height of the wall
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(excluding the first 1 foot below the surface). Composite drainage mats such as Mira Drain 6000
installed in accordance with the manufacturer’s recommendations may be used in lieu of the
free-draining aggregate blanket for walls such as stormwater detention vaults that will not be
completed as finished habitable space on the interior. The drainage aggregate or composite drain
mats should tie into and freely communicate with the footing drains. Roof and surface runoff
should not discharge into the footing drain system, but should be handled by a separate, rigid,
tightline drain.
To minimize erosion, stormwater discharge or concentrated runoff should not be allowed to flow
down any steep slopes. In planning, exterior grades adjacent to walls should be sloped downward
away from the structures at an inclination of at least 3 percent to achieve surface drainage.
Runoff water from impervious surfaces should be collected by a storm drain system that
discharges into the site stormwater system.
15.0 FLOOR SUPPORT
Floor slabs can be supported on 2 feet of new structural fill or cement-treated subgrade soils as
described in the “Site Preparation” section of this report and need not be underlain by aggregate
piers. Foregoing aggregate piers below the floor slab will result in substantial cost savings, but
will result in some risk of larger than normal post-construction settlement of floor slabs due to
potential variabilities in underlying existing fill which will be relied on for floor support. If the risk
of larger than normal floor slab settlement is not acceptable, floor slabs should be supported by
aggregate piers in a manner similar to foundation support as previously discussed. All fill placed
beneath the slab must be compacted to at least 95 percent of ASTM D-1557. The floors should
be cast atop a minimum of 4 inches of washed pea gravel or washed crushed rock to act as a
capillary break where moisture migration through the slabs is to be controlled. The capillary break
material should be overlain by a 10-mil-thick vapor barrier material prior to concrete placement.
American Concrete Institute (ACI) recommendations should be followed for all concrete
placement.
16.0 FOUNDATION WALLS
The following recommendations may be applied to conventional walls up to 8 feet tall. We should
be allowed to offer situation-specific input if any taller walls are planned. All backfill behind
foundation walls or around foundation units should be placed in accordance with our
recommendations for structural fill and as described in this report. Horizontally backfilled walls,
which are free to yield laterally at least 0.1 percent of their height, may be designed to resist
lateral earth pressure represented by an equivalent fluid equal to 35 pcf. Fully restrained,
horizontally backfilled, rigid walls that cannot yield should be designed for an equivalent fluid of
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50 pcf. Walls with sloping backfill up to a maximum gradient of 2H:1V should be designed using
an equivalent fluid of 55 pcf for yielding conditions or 75 pcf for fully restrained conditions. If
parking areas are adjacent to walls, a surcharge equivalent to 2 feet of soil should be added to
the wall height in determining lateral design forces.
As required by the 2018 IBC, retaining wall design should include a seismic surcharge pressure in
addition to the equivalent fluid pressures presented above. Considering the site soils and the
recommended wall backfill materials, we recommend a seismic surcharge pressure of
5H and 10H psf, where H is the wall height in feet for the “active” and “at-rest” loading
conditions, respectively. The seismic surcharge should be modeled as a rectangular distribution
with the resultant applied at the midpoint of the walls
The lateral pressures presented above are based on the conditions of a uniform backfill consisting
of excavated on-site soils or imported structural fill compacted to 90 percent of ASTM D-1557
within about 3 feet of the wall. A higher degree of compaction is not recommended, as this will
increase the pressure acting on the walls. A lower compaction may result in settlement of the
slab-on-grade or other structures supported above the walls. Thus, the compaction level is critical
and must be tested by our firm during placement. Surcharges from adjacent footings or heavy
construction equipment must be added to the above values. Perimeter footing drains should be
provided for all retaining walls, as discussed under the “Drainage Considerations” section of this
report.
It is imperative that proper drainage be provided so that hydrostatic pressures do not develop
against the walls. Wall drainage recommendations are presented in Section 14.0 of this report.
16.1 Passive Resistance and Friction Factors
Lateral loads can be resisted by friction between the foundation and the natural soils or
supporting structural fill soils, and by passive earth pressure acting on the buried portions of the
foundations. The foundations must be backfilled with structural fill and compacted to at least
95 percent of the maximum dry density to achieve the passive resistance provided below. We
recommend the following allowable design parameters which include a factor of safety of 1.5:
• Passive equivalent fluid = 250 pcf
• Coefficient of friction = 0.35
17.0 INFILTRATION RECOMMENDATIONS AND ESTIMATED DESIGN INFILTRATION RATES
Generally, our explorations encountered existing fill soils underlain by Vashon advance outwash.
In our opinion based on our reconnaissance, document research, subsurface exploration,
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infiltration testing, and geologic interpretations, the Vashon advance outwash at depth at this
site will be a suitable infiltration receptor horizon for stormwater generated onsite.
We conducted an infiltration study during the week of March 1st, 2021. Our test locations are
designated IT-1 through IT-5 and the approximate locations are shown on the “Site and
Exploration Plan,” Figure 2. The testing depths ranged between 9 and 14 feet below the existing
ground surface and the field rates ranged from about 4 to 40 inches per hour. The infiltration
rate test results reflect variability both vertically and laterally within the Vashon advance
outwash. Lenses and interbeds of low-permeability, silty sediments can impede vertical
infiltration of water and affect infiltration rates achievable on a long-term basis. Groundwater
was not encountered during any of our subsurface explorations and our explorations have
demonstrated that unsaturated conditions exist in the advance outwash below the site to a depth
of 76.5 feet below the existing ground surface at the location of EB-2W. The well was screened
from 75 to 65 feet and has been dry since installation. Existing fill soils are not considered to be
a suitable receptor soil for stormwater infiltration due to their high variability and high
percentage of fine-grained particles. Shallow infiltration into advance outwash sediments is
feasible in our opinion using underground perforated Corrugated Metal Pipe (CMP) stormwater
detention pipes as currently proposed.
AESI recommends that the infiltration facility bases be situated a minimum of 3 feet into the
native Vashon advance outwash in order to access the un-weathered Vashon advance outwash
sediments. Any existing fill or other deleterious materials that are within the footprint of the
infiltration facility and deeper than the planned infiltration facility base should be removed and
replaced with suitable drainage aggregate.
17.1 Estimated Design Infiltration Rate
The City of Federal Way has adopted the 2016 KCSWDM. Correction factors are described in
Section 5.2 “Preliminary Design Infiltration Rates.” The design infiltration rate needs to take into
account not just the tested interval, but also the geological setting; e.g., similar sediment types
below the infiltration horizon vs. wide variability, both laterally and vertically, within the
sediments below and in the vicinity of the infiltration facility. Based on explorations completed
in the vicinity of the proposed infiltration facilities, sediment types are variable and discontinuous
over relatively short distances.
The design infiltration rates were derived using the correction factors for testing, facility
geometry, and plugging, per the following formula as described in the 2016 KCSWDM,
Section 5.2.1:
Idesign = Imeasured x Ftesting x Fgeometry x Fplugging
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Idesign and Imeasured are the design and measured infiltration rates. According to the 2016 KCSWDM,
correction factor Ftesting accounts for uncertainties in the testing methods. The correction factor
for the PIT Ftesting is 0.5.
The Fgeometry correction factor accounts for the influence of facility geometry and depth to the
water table or impervious strata on the field-based infiltration rate. The KCSWDM states that this
factor must be between 0.25 and 1.0, as determined by the following equation:
Fgeometry = 4 D/W + 0.05
Where D = Depth from the bottom of the proposed facility to the maximum wet season water
table or nearest impervious layer, whichever is less; and W = Width of the facility. The KCSWDM
requires a minimum vertical separation of 5 feet between the base of an infiltration facility and
the seasonal high groundwater level or a restrictive stratum. The minimum vertical separation
can be reduced to as little as 3 feet if it can be demonstrated through a mounding analysis that
the reduced separation will not impact infiltration facility performance. At the time of our
explorations, no groundwater was observed in boring EB-2W since installation, indicating that
groundwater is below about elevation 212 feet. The ground surface elevation at the proposed
infiltration facilities is approximately 290 feet. Water level monitoring will continue through the
wet season. The monitoring program is intended to document that there is adequate vertical
separation from the base of the proposed stormwater infiltration system and groundwater.
At the time of this report, specific infiltration facility depths have not been determined. The
facility type consists of rectangular underground infiltration chambers. We selected a value for
Fgeometry of 1.0 because the depth to groundwater is greater than 50 feet.
The plugging factor (Fplugging) is based on the grain size of the materials tested. The options for
this factor are:
• 0.7 for loams and sandy loams;
• 0.8 for fine sands and loamy sands;
• 0.9 for medium sands; and
• 1.0 for coarse sands and cobbles, or any soil type in an infiltration facility preceded by a
water quality facility.
We selected a value of 0.7 based on the potential for fine sand layering observed in our
explorations and the difficulty in maintaining an underground infiltration structure. This factor
and the maintenance considerations should be reviewed by the civil engineer and owner.
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The estimated preliminary design infiltration rates for the infiltration facilities range from 1.5 to
14.8 inches per hour for the referenced correction factors. The correction factors used and the
resulting Idesign preliminary design infiltration rates are shown in Table 3.
The specific factors derived for individual test results are summarized in Table 3. The
recommended long-term design infiltration rates shown in the last column of Table 3 represent
the maximum allowable long-term design rate after the correction factors have been applied.
The facility-specific design infiltration rate is based upon the field infiltration testing, grain-size
distribution testing, subsurface exploration, groundwater level data, and AESI’s experience on
projects with similar site conditions. The design infiltration rates given above requires that a
representative of AESI observe the subgrade, is present during the excavation and backfilling of
the infiltration facilities, and completes performance verification testing of the subgrade at the
time of construction.
Table 3
Correction Factors and Preliminary Design Infiltration Rates
Facility Name Test No.
Field
Infiltration
Rate
(in/hr)
(Imeasured) Ftesting Fgeometry Fplugging
Preliminary
Design
Infiltration
Rate (in/hr)
Facility
Design
Infiltration
Rate
(Idesign)
CMP Pipes #1 IT-1 12.0 0.5 1.0 0.7 4.2 4.2* IT-2 42.3 0.5 1.0 0.7 14.8
CMP Pipes #2 IT-5 21.6 0.5 1.0 0.7 7.5 7.5
CMP Pipes #3 IT-4 22.4 0.5 1.0 0.7 7.8 7.8
Optional
Field Facility IT-3 4.3 0.5 1.0 0.7 1.5 1.5
in/hr = inches per hour
CMP = Corrugated Metal Pipe
*If the design includes a series of infiltration trenches or pit drains below the facility subgrade, the design infiltration rate would
be based on the geometric mean of infiltration tests IT-1 and IT-2, which is 7.9 inches per hour.
17.2 Infiltration Facility Subgrade Recommendations
For the design infiltration rate to be achieved, the infiltration facility base must be excavated
through any encountered existing fill and unsuitable soils, if encountered, and that the base of
the infiltration facility be embedded a minimum of 3 feet into the Vashon advance outwash that
is consistent with the outwash encountered during infiltration testing.
We have the following comments and recommendations:
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1. The base of the infiltration facilities should be situated a minimum of 3 feet into the native
outwash sediments. AESI should confirm the required minimum embedment into
outwash sediments at the time of construction.
2. The infiltration facility subgrade should be scarified prior to placement of import
aggregate. Care should be taken to limit compaction of the subgrade. Compaction of the
subgrade will reduce the infiltration capacity.
3. Due to natural variability of the subsurface conditions, the potential for field adjustments
should be anticipated based on actual conditions encountered during construction.
4. Depending on the season the infiltration facility is constructed, perched water within the
fill should be anticipated. The contractor should be prepared to handle the perched
water.
5. Due to the natural stratification of the Vashon advance outwash soils it may be necessary
to include shallow infiltration trenches below the bottom of facility. The advance outwash
is stratified with occasional interbeds of fine-grained layers. Infiltrating water may
become perched on these fine-grained layers and slow the infiltration rate. Shallow
infiltration trenches at the base of an infiltration facility allow for stormwater to access
the coarse-grained layers and maintain the design infiltration rates with time. We are
available to help with design of the infiltration subgrade infiltration trenches on request.
17.3 Protection of Subgrade and Infiltration Facilities During Construction
We recommend that excavation equipment should not be allowed on the infiltration facility
subgrade, and care should be taken to minimize disturbance and compaction of the infiltration
surface.
Construction of infiltration facilities during seasonal wet weather can be very difficult. Rain
events that occur when infiltration facilities are under construction and incomplete can cause
significant damage that requires costly repairs. We recommend that project bid documents
require construction of infiltration facilities during the summer when wet weather is less likely.
Care must be taken to ensure the import aggregate products are clean and free of fines.
Stockpiled backfill materials must be protected from site soils and run-on from silt-contaminated
surfaces.
Once the facility is excavated and constructed, the contractor must provide temporary protection
of the facility to keep turbid water and fine-grained sediments out of the facility. Uncontrolled
runoff into the infiltration facility will contaminate the subgrade with fine-grained sediments,
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constitute failure of the subgrade, requiring removal of all backfill materials and contaminated
subgrade, and replacement with clean backfill materials.
The infiltration facility must not be used to infiltrate stormwater during construction. All
construction site stormwater should be directed to a suitable location as specified on the
approved temporary erosion and sedimentation control (TESC) plan.
The infiltration facility must be kept isolated from influent flows until after the site has been
stabilized, so that construction runoff is not introduced into any infiltration facility.
17.4 Construction Phase Performance Infiltration Testing Recommendations
The City may require performance infiltration testing or a signed letter verifying that the
Best Management Practices (BMPs) have been inspected, installed correctly, and are functioning
as designed. We recommend that AESI observe the subgrade, be present during the excavation
and backfilling of the infiltration facilities, and complete performance verification infiltration
testing at the time of construction, instead of after the underground infiltration facility is
backfilled.
Following excavation of the infiltration facilities, we recommend that the exposed subgrade be
infiltration tested by a representative of AESI to establish a baseline level of infiltration
performance prior to placement of the infiltration chambers and imported aggregate.
Water supply is the responsibility of the contractor. Typically, fire hydrant(s) will be used to
provide a continuous supply of water during the infiltration tests. The flow rate, total volume,
and stage height/water level will be recorded at regular intervals (usually 15 minutes).
17.5 Converting the Infiltration Facility to On-Line Status
Prior to bringing the infiltration facility on-line, the following elements must be achieved:
1. All planned earthwork must be complete.
2. Site stabilization must be complete:
a. All permanent groundcover in place.
b. No exposed topsoil.
c. Hydroseeded areas must have established growth sufficient to fix topsoil in place.
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d. No visible sediment transport by stormwater during rain events.
e. Catch-basin filter socks should no longer be needed and shall be removed.
3. Hard surfaces such as paving and sidewalks must be cleaned with no visible sediment or
substances that could be transported by stormwater.
4. All stormwater collection system components must be cleaned and inspected:
a. All catch basins, manholes, and similar structures shall be cleaned by rinsing and
vacuuming to remove visible sediment. No water used in the cleaning of the
upstream system shall be discharged into the infiltration facility.
b. All stormwater pipes shall be jetted to remove visible sediment.
c. After cleaning, a video survey shall be completed of all pipes and structures in the
stormwater collection system. The owner shall be notified prior to the video
survey work so they may observe the work in progress if desired. A recording of
the video survey shall be provided to the owner, civil engineer, and AESI. The
survey shall include sufficient detail to correlate video images with on-site
locations.
5. AESI shall be notified that construction is complete, and shall be allowed to install
long-term monitoring components such as water level loggers, if applicable, before water
is routed to the infiltration facility.
6. The owner, civil engineer, and AESI must be notified that the above items have been
completed, and must concur that the above items have been satisfactorily completed.
7. Written authorization must be provided from the owner, civil engineer, and AESI to the
contractor that water may be routed to the infiltration facility for disposal.
8. Following the first substantial rain event after the infiltration facility is brought on-line,
the system shall be visually inspected. The contractor shall contact the owner, civil
engineer, and AESI to attend the inspection, and shall open facility enclosures, catch
basins, manholes, and other structures as needed to allow visual inspection.
17.6 Recommendations for Future Infiltration-Related Study
We recommend that AESI be allowed to review infiltration design details prior to finalizing plans.
Because the infiltration test locations were offset from infiltration facility locations, confirmatory
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infiltration rate testing is recommended after the existing buildings are demolished and before
the new infiltration facilities are constructed. Confirmatory infiltration rate testing will be
included in our construction phase services proposal for the project.
18.0 PAVEMENT AND SIDEWALK RECOMMENDATIONS
The pavement sections included in this report section are for driveway and parking areas onsite,
and are not applicable to right-of-way improvements. At this time, we are not aware of any
planned right-of-way improvements; however, if any new paving of public streets is required, we
should be allowed to offer situation-specific recommendations.
Pavement and sidewalk areas should be prepared in accordance with the “Site Preparation”
section of this report. Soft or yielding areas should be overexcavated to provide a suitable
subgrade and backfilled with structural fill.
New paving may include areas subject only to light traffic loads from passenger vehicles driving
and parking, and may also include areas subject to heavier loading from vehicles that may include
buses, fire trucks, food service trucks, and garbage trucks. In light traffic areas, we recommend a
pavement section consisting of 3 inches of hot-mix asphalt (HMA) underlain by 4 inches of
crushed surfacing base course. In heavy traffic areas, we recommend a minimum pavement
section consisting of 4 inches of HMA underlain by 2 inches of crushed surfacing top course and
4 inches of crushed surfacing base course. The crushed rock courses must be compacted to
95 percent of the maximum density, as determined by ASTM D-1557. All paving materials should
meet gradation criteria contained in the current Washington State Department of Transportation
(WSDOT) Standard Specifications.
Depending on construction staging and desired performance, the crushed base course material
may be substituted with ATB beneath the final asphalt surfacing if desired. The substitution of
ATB should be as follows: 4 inches of crushed rock can be substituted with 3 inches of ATB, and
6 inches of crushed rock may be substituted with 4 inches of ATB. ATB should be placed over a
native or structural fill subgrade compacted to a minimum of 95 percent relative density, and a
1½- to 2-inch thickness of crushed rock to act as a working surface. If ATB is used for construction
access and staging areas, some rutting and disturbance of the ATB surface should be expected to
result from construction traffic. The general contractor should remove affected areas and replace
them with properly compacted ATB prior to final surfacing.
Subsurface Exploration, Geologic Hazard, Infiltration Design,
Olympic View K-8 School and Geotechnical Engineering Report
Federal Way, Washington Design Recommendations
March 30, 2021 ASSOCIATED EARTH SCIENCES, INC.
ART/ld - 20200286E001-4 Page 33
19.0 PROJECT DESIGN AND CONSTRUCTION MONITORING
We recommend that AESI perform a geotechnical review of the plans prior to final design
completion. In this way, we can confirm that our recommendations have been correctly
interpreted and implemented in the design. The City of Federal Way may require a plan review
by the geotechnical engineer as a condition of permitting.
We recommend that AESI be retained to provide geotechnical special inspections during
construction, and preparation of a letter summarizing our construction phase work when
construction is complete. The City of Federal Way may require such geotechnical special
inspections. The integrity of the earthwork and foundations depends on proper site preparation
and construction procedures. In addition, engineering decisions may have to be made in the field
in the event that variations in subsurface conditions become apparent.
We have enjoyed working with you on this study and are confident these recommendations will
aid in the successful completion of your project. If you should have any questions or require
further assistance, please do not hesitate to call.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
______________________________
Aaron R. Turnley, G.I.T.
Staff Geologist
______________________________
Bruce W. Guenzler, L.E.G. Kurt D. Merriman, P.E.
Senior Associate Geologist Senior Principal Engineer
Attachments: Figure 1. Vicinity Map
Figure 2. Site and Exploration Plan
Figure 3. Proposed Site and Exploration Plan
Figure 4. Critical Aquifer Recharge Areas
Appendix A. Exploration Logs
Appendix B. Laboratory Testing Results
Appendix C. Infiltration Test Data Sheets
DATA SOURCES / REFERENCES:
USGS: 7.5' SERIES TOPOGRAPHIC MAPS, ESRI/I-CUBED/NGS 2013
KING CO: STREETS, CITY LIMITS, PARCELS, PARKS 3/20
LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE
VICINITY MAP
OLYMPIC VIEW K-8 SCHOOL
FEDERAL WAY, WASHINGTON
20200286E001 11/20 1
±
0 2000
Feet
PROJ NO.
NOTE: BLACK AND WHITE
REPRODUCTION OF THIS COLOR
ORIGINAL MAY REDUCE ITS
EFFECTIVENESS AND LEAD TO
INCORRECT INTERPRETATION DATE:FIGURE:G:\GIS_Projects\aaY2020\200286 Olympic View\aprx\200286E001 F1 VM_ OlyView.aprx | 200286E001 F1 VM_ OlyView | 11/2/2020 12:14 PM¥
¬«
¬«509
!(26th Ave SWSW 327th St
Pierce County
King County
SITE
Pierce County
King County
!(
BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAY REDUCE ITS
EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION
G:\GIS_Projects\aaY2020\200286 Olympic View\aprx\20200286E001 F2 ES_OlyView.aprx | 20200286E001 F2 ES_OlyView | 3/15/2021 11:49 AMPROJ NO.DATE:FIGURE:
0 150
FEET
DATA SOURCES / REFERENCES:
PSLC: KING COUNTY 2016, GRID CELL SIZE IS 3'.
DELIVERY 2 FLOWN 2/25/16 - 3/28/16
CONTOURS FROM LIDAR
KING CO: STREETS, PARCELS, 3/20
AERIAL PICTOMETRY INT. 2019
LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE
20200286E001 3/21 2
EXISTING SITE AND
EXPLORATION PLAN
OLYMPIC VIEW K-8 SCHOOL
FEDERAL WAY, WASHINGTON
!(
!(
!(
!(
!(!(
!(!(
!(!(
!(
!(
!(
!(
!(
!(
!(
!(
S W 3 2 3 rdS t26th Ave SWSW 327th St
EB-1EB-2W
EB-3
EB-4
EB-5
EB-6
EB-7
EB-8
EB-9
EB-10
EB-11
EB-12
EB-13
EB-14
EB-15 EB-16
EB-17EB-18
EB-19
300290
280
270
260
250
240
230
330320310300310
30
0
310
290250 IT-1IT-2IT-3
EP-1
EP-2
IT-4
IT-5
EagleView Technologies, Inc.
LEGEND
SITE
EXPLORATION PIT - 2021
INFILTRATION TEST - 2021
!(EXPLORATION BORING - 2021
!(EXPLORATION BORING - 2020
MONITORING WELL - 2020
PARCEL
CONTOUR 10 FT
CONTOUR 2 FT
Pierce County
King County
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(!(
!(
!(
!(
!(%,%,%,")")%,%,EB-1, 16ft
EB-2W, 13ft
EB-3, 8ft
EB-4, 17ft
EB-5, 14ft
EB-6, 21ft
EB-7, 21ft
EB-8, 6.5ft
EB-9, 12.5ft
EB-10, 8ft
EB-11, 8ft
EB-12, 12.5ft
EB-13, 17.5ft
EB-14, 22.5ft
EB-15, 18ft
EB-16, 18ft
EB-17, 13ft
EB-18, 21ft
EB-19, 15ft
IT-1, 8ft
IT-2, 6ft
IT-3, 8ft
EP-1, 8ft
EP-2, 3ft
IT-4, 7ft IT-5, 6ft
BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAY REDUCE ITS
EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION
G:\GIS_Projects\aaY2020\200286 Olympic View\aprx\20200286E001 F3 SP_OlyView.aprx | 20200286E001 F3 SP_OlyView | 3/16/2021 10:16 AMPROJ NO.DATE:FIGURE:
0 100
FEET
DATA SOURCES / REFERENCES:
MCGRANAHAN ARCHITECTS, OLYMPIC VIEW K-8 (OLV),
OVERALL DRAINAGE PLAN, SHEET C4.00, 2/4/21
KING CO: PARCELS 3/20
LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE
20200286E001 3/21 3
PROPOSED SITE AND
EXPLORATION PLAN
OLYMPIC VIEW K-8 SCHOOL
FEDERAL WAY, WASHINGTON
LEGEND
SITE
")EXPLORATION PIT, DEPTH OF FILL -
2021
%,INFILTRATION TEST, DEPTH OF FILL -
2021
!(EXPLORATION BORING, DEPTH OF FILL
- 2021
!(EXPLORATION BORING, DEPTH OF FILL
- 2020
MONITORING WELL, DEPTH OF FILL -
2020
WELL 19A
WELL
20A
WELL
23A
WELL 17
WELL 18
WELL 7
WELL 15
WELL 10
WELL 10A
WELL 17A
TACOMA WATER DIVISION CITY OFLAKEHAVEN WATER AND SEWER DISTRICTPROJ NO.
NOTE: BLACK AND WHITE
REPRODUCTION OF THIS COLOR
ORIGINAL MAY REDUCE ITS
EFFECTIVENESS AND LEAD TO
INCORRECT INTERPRETATION DATE:FIGURE:
±G:\GIS_Projects\aaY2020\200286 Olympic View\aprx\20200286E001 F4 CARA_OlyView.aprx | 20200286E001 F4 CARA_OlyView | 10/31/2020 1:21 PMDATA SOURCES / REFERENCES:
DOH 12/19: WELLHEAD PROTECTION AREAS, LHWD GROUP A
USGS: 7.5' SERIES TOPOGRAPHIC MAPS, ESRI/I-CUBED/NGS 2013
LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE
0 2000
Feet
WELLHEAD
PROTECTION ZONES
OLYMPIC VIEW K-8 SCHOOL
FEDERAL WAY, WASHINGTON
20200286E001 11/20 4
LEGEND
SITE
SITE BUFFER 1300'
WATER DISTRICT
SERVICE
BOUNDARY
TIME OF TRAVEL
6 MONTH
1 YEAR
5 YEAR
10 YEAR
APPENDIX A
Exploration Logs
Elev: 289 ft
Grass / Topsoil - 6 inches
Medium dense, moist, brown, silty, fine to medium SAND, some coarse sand, some gravel;
unsorted (SM).
Fill
Medium dense, moist, brown, silty, medium to coarse SAND, some fine sand, some gravel, trace
cobble; unsorted (SM).
Vashon Advance Outwash
Dense, moist, grayish brown, fine SAND, trace silt; occasional silt laminations; massive (SP).
Dense, grayish brown, fine to coarse SAND, some silt, some gravel, trace cobble; unsorted
(SP-SM).
Dense, moist, grayish brown, fine SAND, some medium to coarse sand, some silt, trace gravel;
occasional silt laminations (SP-SM).
Dense, moist, grayish brown, fine SAND, some coarse sand, trace silt, trace gravel; massive (SP).
Bottom of exploration pit at depth 18.5 feet
No seepage. Minor caving 8 to 18.5 feet.
DESCRIPTION
Approved by: JHS
Federal Way, WA
EXPLORATION PIT NO. EP-1
Olympic View K-8 School
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered.
Logged by: ART
3/1/21
Project No. 20200286E001Depth (ft)KCTP3 20200286E001.GPJ March 25, 2021
Elev: 288 ft
Grass / Topsoil - 6 inches
Medium dense, moist, brown, silty, fine to medium SAND, some coarse sand, some gravel;
unsorted (SM).
Fill
Medium dense, moist, brown, silty, fine SAND, some medium to coarse sand, some gravel;
unsorted (SM).
Vashon Lodgement Till / Till Fill?
Very dense, moist, brownish gray with iron oxide staining, silty, fine SAND, some medium to coarse
sand, some gravel; diamict; unsorted (SM).
Vashon Advance Outwash
Dense, moist, brown, medium to coarse SAND, some silt, some fine sand, some gravel; unsorted
(SP-SM).
Dense, moist, grayish brown, fine SAND, some gravel, trace silt; occasional silt laminations (SP).
Dense, moist, grayish brown, fine SAND, some coarse sand, some gravel, trace silt, trace cobble
(SP).
Dense, moist, grayish brown, fine SAND, trace silt, trace gravel; massive (SP).
Bottom of exploration pit at depth 18.5 feet
No seepage. Minor caving 9 to 18.5 feet.
DESCRIPTION
Approved by: JHS
Federal Way, WA
EXPLORATION PIT NO. EP-2
Olympic View K-8 School
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered.
Logged by: ART
3/1/21
Project No. 20200286E001Depth (ft)KCTP3 20200286E001.GPJ March 25, 2021
Elev: 290 ft
Grass / Topsoil - 6 inches
Medium dense, moist, light brown, silty fine SAND, some medium to coarse sand, some gravel,
some cobbles; unsorted (SM).
Fill
Medium dense to loose, moist, gray to dark brown, silty, fine SAND, some medium sand; occasional
boulders and cobbles; organics observed; organic odor (SM).
Vashon Advance Outwash
Dense, moist, brown, medium to coarse SAND, some silt, some fine sand, some gravel (SM).
Dense, moist, brownish orange, gravelly, fine SAND, some silt; stratified (SP-SM).
Dense, moist, brownish orange, fine SAND, some gravel, trace silt (SP).
Dense, moist, grayish brown, fine to medium SAND, some gravel, trace silt; stratified (SP).
Bottom of exploration pit at depth 15 feet
No seepage. Minor caving 6 to 15 feet. Infiltration test performed at 10 feet.
DESCRIPTION
Approved by: JHS
Federal Way, WA
EXPLORATION PIT NO. IT-1
Olympic View K-8 School
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered.
Logged by: ART
3/1/21
Project No. 20200286E001Depth (ft)KCTP3 20200286E001.GPJ March 25, 2021
Elev: 290 ft
Fill
Loose, moist, brownish gray, fine SAND, trace silt; massive (utility sand for long jump) (SP).
Medium dense to loose, moist, brown, silty, fine SAND, some medium to coarse sand, some gravel;
occasional organic debris; unsorted (SM).
Layer of rootlets 3 to 4 feet.
Vashon Advance Outwash
Medium dense, moist, brown, fine SAND, trace silt; occasional horizontal silt laminations (SP).
Dense, moist, grayish brown, fine to medium SAND, trace silt, trace gravel; occasional horizontal silt
laminations (SP).
Dense, moist to wet, grayish brown, medium to coarse SAND, some gravel, trace silt, trace cobbles;
non-continuous silt lamination (1 inch thick) in sidewall (SP).
Dense, moist, brown, GRAVEL, some medium to coarse sand, some silt; silt coated gravels
(GP-GM).
Dense, moist, brownish grey, medium to coarse SAND, some gravel, some fine sand, trace silt
(SP).
Bottom of exploration pit at depth 18.5 feet
Seepage observed during over-excavation at ~12 feet. Minor caving 9 to 18.5 feet. Infiltration test performed at 9 feet.
DESCRIPTION
Approved by: JHS
Federal Way, WA
EXPLORATION PIT NO. IT-2
Olympic View K-8 School
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered.
Logged by: ART
3/2/21
Project No. 20200286E001Depth (ft)KCTP3 20200286E001.GPJ March 25, 2021
Elev: 289 ft
Grass / Topsoil - 6 inches
Fill
Medium dense, moist, brown, silty, fine to medium SAND, some coarse sand, some gravel; broken
ceramic tiles; unsorted (SM).
Fill / Vashon Lodgement Till
Very dense, moist, brown, silty medium to coarse SAND, some fine sand, some gravel, trace
cobble; unsorted (SM)
Vashon Advance Outwash
Dense, moist, brownish grey, medium to coarse SAND, some silt, some gravel; stratified (SP-SM).
Dense, moist, grayish brown, fine to medium SAND, some coarse sand, some gravel, some silt;
occasional horizontal silt laminations (SP-SM).
Dense, moist, grayish brown, fine to medium SAND, some silt, trace gravel, trace coarse sand;
occasional horizontal silt laminations, fining down (SP-SM).
Dense, moist, brownish gray, very sandy, GRAVEL, trace silt; non-continuous silt lamination (1 to 2
inches thick) ~2 feet under test (GP).
Dense, moist, brownish gray, fine to medium SAND, trace silt, trace gravel, trace coarse sand;
occasional horizontal silt laminations (SP).
Bottom of exploration pit at depth 18.5 feet
Seepage observed at 16 feet. Minor caving 7 to 18.5 feet. Infiltration test performed at 14 feet.
DESCRIPTION
Approved by: JHS
Federal Way, WA
EXPLORATION PIT NO. IT-3
Olympic View K-8 School
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered.
Logged by: ART
3/3/21
Project No. 20200286E001Depth (ft)KCTP3 20200286E001.GPJ March 25, 2021
Elev: 290 ft
Grass / Topsoil - 6 inches
Medium dense, moist, light brown, silty, fine to medium SAND, some gravel; rootlets observed;
unsorted (SM).
Fill
Medium dense, moist, grayish brown with alternating grayish brown to brownish gray color (fill lifts),
silty, fine SAND, some medium sand, some gravel, trace cobbles (SM).
Vashon Advance Outwash
Black stripping layer 7 to 7.5 feet.
Medium dense, moist, light brown, fine SAND, some silt (SP-SM).
Dense, moist, brownish gray, fine to medium SAND, some gravel, trace silt; occasional horizontal
silt laminations (SP).
Dense, moist, brownish gray, gravelly, fine to medium SAND, trace silt; occasional horizontal silt
laminations, fining down (SP).
As above.
As above.
Dense, moist, brownish grey, medium to coarse SAND, some gravel, trace fine sand, trace silt (SP).
Bottom of exploration pit at depth 18.5 feet
No seepage. Minor caving at 11 feet. Infiltration test performed at 11 feet.
DESCRIPTION
Approved by: JHS
Federal Way, WA
EXPLORATION PIT NO. IT-4
Olympic View K-8 School
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered.
Logged by: ART
3/4/21
Project No. 20200286E001Depth (ft)KCTP3 20200286E001.GPJ March 25, 2021
Elev: 288 ft
Grass / Topsoil - 6 inches
Vashon Lodgement Till / Till Fill?
Very dense, moist, grayish brown, silty, fine SAND, some gravel; unsorted; diamict (SM).
Vashon Advance Outwash
Dense, moist, brownish gray, fine to medium SAND, some gravel, some coarse sand, trace silt
(SP).
Dense, moist, brownish gray, fine SAND, some medium sand, trace gravel, trace silt; occasional
horizontal silt laminations (SP).
Dense, moist, grayish brown, fine to medium SAND, some coarse sand, trace silt, trace gravel (SP).
Dense, moist, grayish brown, medium to coarse SAND, some gravel, trace fine sand, trace silt (SP).
Bottom of exploration pit at depth 18.5 feet
No seepage. Minor caving at 11 feet. Infiltration test performed at 11 feet. No test water re-entering during
over-excavation.
DESCRIPTION
Approved by: JHS
Federal Way, WA
EXPLORATION PIT NO. IT-5
Olympic View K-8 School
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered.
Logged by: ART
3/5/21
Project No. 20200286E001Depth (ft)KCTP3 20200286E001.GPJ March 25, 2021
Bottom of exploration boring at 21 feet
No groundwater encountered.
23
22
22
50/6"
34
22
20
43
50/5"
Grass - 4 inches
Fill
Medium dense, moist, brownish gray, gravelly, fine to medium SAND, trace
silt (SP).
Hand dug 0 to 2 feet to clear irrigation.
Moist, grayish brown, silty, fine to medium SAND, some broken gravel
(SM).
Driller notes chattering at 7.5 feet.
Moist, brown, silty, fine to medium, SAND, some gravel; broken gravel in
tip; poor recovery (SM).
As above.
Vashon Advance Outwash
Lower 2 inches: moist, grayish brown, fine to medium SAND, some silt;
massive (SP-SM).
Driller notes chattering at 17 feet.
No recovery.
S-1
S-2
S-3
S-4
S-5
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
10/7/20,10/7/20
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
288
5
10
15
20
25
30
35
EB-1
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20214444
5050/6"
4242
5050/5"
17
28
40
45
22
29
9
10
12
14
26
30
10
13
13
40
42
49
12
20
28
Flush mount monument
Concrete 0 to 2.5 feet
Bentonite chips 2.5 to 62 feet
2-inch I.D. Sch 40 PVC
casing 0 to 65 feet
Bentonite chips 2.5 to 62 feet
Fill
Medium dense, moist, brownish tan, silty, fine to medium SAND,
trace gravel, trace organics (SM).
Hand dug 0 to 2.5 feet to clear irrigation.
Upper 6 inches: moist, brownish tan with some iron oxide staining,
silty, fine to medium SAND, trace gravel, trace organics (SM).
Lower 12 inches: moist, grayish brown, silty, gravelly, SAND;
contains broken gravel (SM).
Driller notes drill chatter.
As above (SM).
Vashon Advance Outwash
Moist, brownish gray, fine to medium SAND, trace silt, trace gravel;
massive (SP).
Driller notes drill chatter.
Moist, grayish brown, fine to coarse SAND, some silt, trace gravel
(broken); poor recovery (SP-SM).
Moist, brownish gray, silty, fine to coarse SAND, some gravel;
unsorted (SM).
Moist, grayish brown, fine to coarse SAND, some silt, some gravel;
broken gravel; poor recovery (SP-SM).
Moist, grayish brown, medium to coarse SAND, some silt, some
gravel (SP-SM).
Driller notes drill chatter.
3" OD Split Spoon Sampler (D & M)
Logged by:
Olympic View K-8 School
EB-2W
2" OD Split Spoon Sampler (SPT) No Recovery
Geologic & Monitoring Well Construction Log
ART
Shelby Tube Sample
Drilling/Equipment
Water Level ()
287 (NAVD88)
Well Number
140# / 30
Project Name
Elevation (Top of Well Casing)Water LevelHole Diameter (in)
Well Tag #
8
Water Level at time of drilling (ATD)
20200286E001
Water Level Elevation
JHS
BJI 136
Approved by:
M - Moisture
S
T
Surface Elevation (ft)
Location
1 of 2
10/7/20,10/7/20
Federal Way, WA
Sampler Type (ST):
WELL CONSTRUCTION GraphicSymbolBlows/6"Sheet
5
10
15
20
25
30
35
Boretec / EC-95 Track Mounted Drill
~286.7
Ring Sample
Project Number
Date Start/Finish
Hammer Weight/Drop
Grab SampleDepth(ft)DESCRIPTION
NWWELL- B 20200286E001.GPJ BORING.GDT 3/23/21
31
40
41
37
50/6"
27
50/5"
28
50/6"
37
50/4"
46
50/5"
50/5"
38
50/6"
2-inch I.D. Sch 40 PVC
casing 0 to 65 feet
10/20 Colorado filter sand 62
to 75 feet
2inch I.D. PVC Sch 40 well
screen 0.010-inch slot width
65 to 75 feet
Threaded end cap
Boring terminated at 76 feet
Well completed at 75 feet on 10/7/20.
No groundwater encountered.
Boring terminated at 76 feet
Well completed at 75 feet on 10/7/20.
No groundwater encountered.
As above; fining downward.
Moist, brownish gray, fine to medium SAND, trace silt, trace coarse
sand; massive (SP).
Moist, grayish brown, fine to coarse SAND, some small gravel, trace
silt (SP).
As above.
Moist, grayish brown, fine to medium SAND, trace silt; massive (SP).
Moist, brownish gray, fine SAND, some medium sand, trace silt;
massive (SP).
As above; slightly coarsens downward.
Moist, brownish gray, fine SAND, trace silt; massive (SP).
3" OD Split Spoon Sampler (D & M)
Logged by:
Olympic View K-8 School
EB-2W
2" OD Split Spoon Sampler (SPT) No Recovery
Geologic & Monitoring Well Construction Log
ART
Shelby Tube Sample
Drilling/Equipment
Water Level ()
287 (NAVD88)
Well Number
140# / 30
Project Name
Elevation (Top of Well Casing)Water LevelHole Diameter (in)
Well Tag #
8
Water Level at time of drilling (ATD)
20200286E001
Water Level Elevation
JHS
BJI 136
Approved by:
M - Moisture
S
T
Surface Elevation (ft)
Location
2 of 2
10/7/20,10/7/20
Federal Way, WA
Sampler Type (ST):
WELL CONSTRUCTION GraphicSymbolBlows/6"Sheet
45
50
55
60
65
70
75
Boretec / EC-95 Track Mounted Drill
~286.7
Ring Sample
Project Number
Date Start/Finish
Hammer Weight/Drop
Grab SampleDepth(ft)DESCRIPTION
NWWELL- B 20200286E001.GPJ BORING.GDT 3/23/21
Bottom of exploration boring at 21.5 feet
No groundwater encountered.
4
5
17
22
26
25
18
17
24
12
18
19
Grass / Topsoil - 4 inches
Fill
Moist, brown, fine to medium silty, SAND, some gravel; occasional rootlets;
broken gravel in tip; poor recovery (SM).
Hand dug to 3 feet to clear irrigation.
As above.
Driller notes drill chatter.
Vashon Advance Outwash
Moist, grayish brown, gravelly, silty, fine to coarse SAND; unsorted;
massive (SM).
Moist, brownish gray, fine to medium SAND, some silt; occasional small
gravel otherwise massive (SP-SM).
As above; fines down; layer (1 inch thick) of slightly oxidized, silty, fine
sand.
S-1
S-2
S-3
S-4
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
10/7/20,10/7/20
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
283
5
10
15
20
25
30
35
EB-3
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20212222
51
4141
3737
Bottom of exploration boring at 16.5 feet
No groundwater encountered.
41
45
42
11
50/6"
27
41
42
Asphalt - 1.5 inches
Fill
Moist, grayish brown, GRAVEL, some sand, some silt; unsorted (GP-GM).
Moist, grayish brown, very gravelly, SAND, some silt; unsorted (SP-SM).
Driller notes drill chatter.
As above.
Driller notes severe drill chattering.
As above.
S-1
S-2
S-3
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
10/7/20,10/7/20
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
289
5
10
15
20
25
30
35
EB-4
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 202187
61
83
Bottom of exploration boring at 26.5 feet
No groundwater encountered.
7
12
11
7
8
8
10
11
10
13
19
18
23
24
29
17
25
20
Grass / Topsoil - 4 inches
Fill
Very moist, grayish brown, silty, fine to medium SAND, some coarse sand,
some gravel; contains organics; unsorted (SM).
Hand dug to 3 feet to clear irrigation.
As above.
As above.
Moist, brownish tan, silty, fine SAND to fine sandy, SILT; contains organics
(SM-ML).
Driller notes harder drill action at 14 feet.
Vashon Advance Outwash
Moist, brown, silty, fine to medium SAND, some gravel, trace coarse sand;
massive (SM).
Driller notes drill chatter.
Moist, brownish gray, silty, fine to medium SAND, some coarse sand,
some gravel; massive (SM).
Moist, brownish gray, fine to medium SAND, trace gravel, trace silt, trace
coarse sand; massive (SP).
S-1
S-2
S-3
S-4
S-5
S-6
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
10/8/20,10/8/20
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
291
5
10
15
20
25
30
35
EB-5
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20212323
1616
2121
3737
53
4545
Bottom of exploration boring at 21.5 feet
No groundwater encountered.
22
17
16
16
15
14
23
26
25
29
31
32
43
50/6"
Grass / Topsoil - 4 inches
(Till) Fill
Moist, brown, silty, fine to medium SAND, some gravel (SM).
Hand dug to 3 feet to clear irrigation .
Moist, brownish gray, silty, fine to medium SAND, some broken gravel
(SM).
As above; faint iron oxide staining.
Fill
Moist, grayish brown, GRAVEL; silty, fine to medium sand in tip; broken
gravel in tip; poor recovery (GP-GM).
Driller notes drill chatter.
Moist, brownish gray, GRAVEL, some fine to medium sand, some silt;
broken gravel; unsorted (GP-GM).
Moist, brownish gray, sandy, GRAVEL, some silt, trace fine sand;
blowcounts are overstated (GP-GM).
S-1
S-2
S-3
S-4
S-5
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
10/8/20,10/8/20
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
287
5
10
15
20
25
30
35
EB-6
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20213333
2929
51
63
93
Bottom of exploration boring at 21.5 feet
No groundwater encountered.
9
4
3
4
10
12
13
8
9
41
50/6"
50/6"
Grass / Topsoil - 4 inches
Fill
Hand dug to 3 feet to clear irrigation.
Moist, black to brown, silty, medium to coarse SAND, some gravel, trace
fine sand; contains organics (SM).
As above; poor recovery.
As above; some silt inclusions.
Fill
Moist, brownish gray, fine to medium SAND, trace silt, trace gravel;
massive (SP).
Driller notes drill chatter at 12 feet.
Moist, brown to black, silty, fine to medium SAND to sandy, SILT, some
broken gravel; pockets of small organics; organic odor; blowcounts are
overstated (SM-ML).
moist, brownish gray, silty, fine to medium SAND, trace gravel; faint
organic odor; unsorted; poor recovery (SM).
S-1
S-2
S-3
S-4
S-5
S-6
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
10/8/20,10/8/20
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
288
5
10
15
20
25
30
35
EB-7
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 202177
2222
1717
91
5050/6"
Bottom of exploration boring at 16.5 feet
No groundwater encountered.
12
39
48
12
19
23
19
23
25
Grass / Topsoil - 4 inches
Fill
Hand dug to 3 feet to clear irrigation.
Moist, brown, fine to medium SAND, some silt, some gravel (SP-SM).
Moist, brown, fine to medium SAND, some silt, some gravel; broken gravel
in tip (SP-SM).
Driller notes drill chatter.
Vashon Advance Outwash
Driller notes hard drilling.
Moist, brown, very gravelly, SAND, some silt; massive (SP-SM).
Moist, brown, fine to medium SAND, some silt, some gravel; occasional
beds of fine sand (SP-SM).
S-1
S-2
S-3
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
10/8/20,10/8/20
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
285
5
10
15
20
25
30
35
EB-8
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 202187
4242
53
Bottom of exploration boring at 36.5 feet
No groundwater encountered.
25
27
28
24
18
27
19
17
16
26
40
42
15
19
18
12
8
9
6
11
15
15
28
30
15
22
45
Asphalt - ~2.5 inches
Fill
Driller notes drill chatter.
Moist, brownish gray, silty, fine to medium SAND, some coarse sand,
some broken gravel (SM).
Driller notes drill chatter.
As above.
Vashon Advance Outwash
Driller notes change in drill action.
Moist, brownish gray, very gravelly, fine to medium SAND, some silt
(SP-SM).
Moist, grayish brown, fine to medium SAND, some gravel, some silt
(SP-SM).
Moist, grayish brown, fine to medium SAND, trace silt (SP).
Moist, grayish brown, fine SAND, trace medium sand, trace silt; occasional
interbeds; massive (SP).
As above.
As above.
As above.
Moist, grayish brown, fine to medium SAND, trace coarse sand, trace
gravel, trace silt (SP).
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
S-9
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/22/21,2/22/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
290
5
10
15
20
25
30
35
EB-9
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 202155
4545
3333
82
3737
1717
2626
58
67
Bottom of exploration boring at 36.5 feet
No groundwater encountered.
4
4
4
7
7
10
12
16
15
9
10
12
7
21
21
7
7
16
9
15
16
7
20
17
10
20
17
14
20
23
10
17
22
Grass / Topsoil - 6 inches
Fill
Moist, brown, silty, fine to medium SAND, trace gravel; unsorted (SM).
Vashon Advance Outwash
Moist, brownish red, gravelly, SAND, some silt (SP-SM).
Moist, brownish gray, fine to coarse SAND, some broken gravel, trace silt
(SP).
Driller notes drill chatter.
Moist, brownish gray, fine to coarse SAND, some silt, trace gravel
(SP-SM).
Moist, brownish gray, fine to coarse SAND, some broken gravel, trace silt
(SP).
Moist, grayish brown with occasional iron oxide banding, fine SAND, trace
silt; occasional silty interbeds; fining downwards; massive (SP).
As above; more gray coloring.
Moist, gray with occasional iron oxide banding, fine SAND, some medium
sand, trace silt; occasional silty interbeds (0.25 inch thick); massive (SP).
As above; no iron oxide banding.
As above.
Moist, grayish brown, fine SAND, some medium sand, trace coarse sand,
trace silt; massive (SP).
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
S-9
S-10
S-11
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/22/21,2/22/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
290
5
10
15
20
25
30
35
EB-10
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 202188
1717
3131
2222
4242
2323
3131
3737
3737
4343
3939
3
3
4
10
7
15
16
12
12
20
20
21
25
36
31
19
19
28
22
19
26
11
18
18
16
28
29
23
29
40
29
35
44
24
36
39
Grass / Topsoil - 6 inches
Fill
Driller notes drill chatter.
Wet, brown, silty, fine to medium SAND, some gravel; unsorted (SM).
Driller notes drill chatter.
Vashon Advance Outwash
Moist, brownish gray, gravelly fine to coarse SAND, some silt; unsorted
(SP-SM).
Driller notes drill chatter.
Moist, brownish gray with occasional iron oxide banding, very gravelly, fine
to medium SAND, some silt; occasional silt interbeds (SP-SM).
Moist, grayish brown, fine to coarse SAND, some gravel, trace silt (SP).
Driller notes drill chatter.
Moist, grayish brown, silty, fine to medium SAND, some broken gravel,
some coarse sand (SM).
Moist, grayish brown, silty, fine to medium SAND, some broken gravel,
some coarse sand; unsorted (SM).
Moist, grayish brown, fine to medium SAND, some broken gravel, trace silt;
fining downwards (SP).
Moist, grayish brown, fine SAND, some medium sand, trace silt (SP).
As above; trace broken gravel.
Moist, gray, fine to coarse SAND, some broken gravel, trace silt;
coarsening downward (SP).
As above.
Driller notes drill chatter.
Moist, grayish brown, fine to medium SAND, some coarse sand, trace
broken gravel, trace silt; massive (SP).
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
S-9
S-10
S-11
S-12
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 2
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/22/21,2/22/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
289
5
10
15
20
25
30
35
EB-11
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 202177
2222
2424
4141
67
57
4545
3636
57
69
79
75
Bottom of exploration boring at 46.5 feet
No groundwater encountered.
24
29
28
20
29
29
Moist, grayish brown, fine SAND, trace silt; massive (SP).
As above; more gray coloration; fining downward.
S-13
S-14
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
2 of 2
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/22/21,2/22/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
289
45
50
55
60
65
70
75
EB-11
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 202157
58
Bottom of exploration boring at 34 feet
No groundwater encountered.
10
14
14
50/6"
24
43
41
24
50/6"
28
50/6"
23
23
44
19
25
29
15
23
31
Fill
Moist, brown, silty, fine SAND, some medium sand, trace gravel; unsorted
(SM).
Driller notes drill chatter.
Moist, brown, silty, fine SAND, some medium to coarse sand; contains
broken gravel; unsorted (SM).
Driller notes drill chatter.
Vashon Advance Outwash
Moist, grayish brown, silty, fine to medium SAND, some broken gravel,
trace coarse sand (SM).
Driller notes drill chatter.
Moist, grayish brown, silty, fine to medium SAND, some gravel; unsorted
(SM).
Driller notes drill chatter.
Moist, brown to gray, silty, fine SAND, some broken gravel; poor recovery
(SM).
Moist, grayish brown, fine to coarse SAND, some silt, some broken gravel
(SP-SM).
As above.
Moist, grayish brown, fine SAND, some medium sand, some gravel, trace
silt; unsorted (SP).
As above.
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/22/21,2/22/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
290
5
10
15
20
25
30
35
EB-12
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20212828
5050/6"
84
5050/6"
5050/6"
72
54
54
Bottom of exploration boring at 36.5 feet
No groundwater encountered.
14
19
17
10
12
12
41
50/6"
50/2"
50/3"
50/4"
23
31
29
17
28
44
Fill
Moist, brown, silty, fine SAND, some broken gravel; poor recovery (SM).
Moist, brown, silty, fine SAND, some coarse sand; contains broken gravel
(SM).
Driller notes drill chatter.
As above; poor recovery.
Driller notes drill chatter.
Moist, brownish gray, silty, fine SAND; poor recovery (SM).
Vashon Advance Outwash
No recovery.
Driller notes drill chatter.
No recovery.
Driller notes drill chatter.
Moist, grayish brown, fine to coarse SAND, some broken gravel, some silt
(SP-SM).
Driller notes drill chatter.
Moist, grayish brown, fine to medium SAND, some broken gravel, trace
coarse sand, trace silt (SP).
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/22/21,2/22/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
286
5
10
15
20
25
30
35
EB-13
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20213636
2424
5050/6"
5050/2"
5050/3"
5050/4"
60
72
Bottom of exploration boring at 31.5 feet
No groundwater encountered.
22
50/6"
13
17
22
19
22
19
25
33
50/6"
22
34
33
20
50/5"
40
50/6"
Fill
Moist, brown, silty, fine SAND, some medium to coarse sand, trace broken
gravel (SM).
Moist, brown, silty, fine SAND, some medium sand, trace gravel; unsorted
(SM).
Driller notes drill chatter.
Moist, brownish gray, fine to medium SAND, some silt, trace gravel;
unsorted (SP-SM).
Driller notes drill chatter.
Moist, brownish gray, silty, fine to medium SAND, some coarse sand;
broken gravel in tip (SM).
Driller reports chattering.
Moist, grayish brown, silty, fine SAND, some medium sand; contains
broken gravel; till-like (SM).
Driller notes drill chatter.
Vashon Advance Outwash
Moist, grayish brown, fine SAND, some silt, some medium to coarse sand,
trace broken gravel; unsorted (SP-SM).
Driller notes drill chatter.
Moist, grayish brown, fine to medium SAND, some coarse sand, trace silt
(SP).
S-1
S-2
S-3
S-4
S-5
S-6
S-7
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/23/21,2/23/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
286
5
10
15
20
25
30
35
EB-14
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20215050/6"
3939
4141
5050/6"
67
5050/5"
5050/6"
Bottom of exploration boring at 26.5 feet
No groundwater encountered.
29
50/5"
27
28
28
45
50/5"
31
50/6"
19
27
25
20
29
41
Fill
Moist, grayish brown, silty, fine SAND, some medium to coarse sand, trace
gravel; unsorted (SM).
Moist, grayish brown, silty, fine SAND, some coarse sand; unsorted (SM).
Driller notes drill chatter.
Moist, grayish brown, silty, fine SAND, trace medium to coarse sand, trace
gravel; poor recovery (SM).
Driller notes drill chatter.
Moist, grayish brown, fine to medium SAND, some silt, trace gravel;
unsorted (SM).
Driller notes drill chatter.
Vashon Advance Outwash
Moist, grayish brown, fine to medium SAND, some gravel, trace silt;
unsorted (SP).
Driller notes drill chatter.
Moist, grayish brown, fine to medium SAND, some coarse sand, trace silt;
contains broken gravel; unsorted (SP).
S-1
S-2
S-3
S-4
S-5
S-6
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/23/21,2/23/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
286
5
10
15
20
25
30
35
EB-15
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20215050/5"
56
5050/5"
5050/6"
52
70
Bottom of exploration boring at 26.5 feet
No groundwater encountered.
12
15
16
7
16
17
23
23
26
25
29
29
20
41
50/6"
12
14
15
Landscaping Mulch - 6 inches
Fill
Moist, grayish brown, silty, fine SAND, some medium sand, some broken
gravel; unsorted (SM).
Upper 6 inches: moist, red, fine sandy, SILT; massive (ML).
Lower 12 inches: moist, gray, silty, fine SAND, some medium sand, some
broken gravel; unsorted (SM).
Driller notes drill chatter.
Moist, reddish brown, fine sandy, SILT, trace coarse sand, trace gravel;
massive (ML).
Moist, grayish brown, fine to medium SAND, some silt; broken gravel;
unsorted (SP-SM).
Driller notes drill chatter.
Vashon Advance Outwash
Moist, grayish brown, fine to medium SAND, trace coarse sand, trace silt;
massive (SP).
Driller notes drill chatter.
Moist, grayish brown, fine to medium SAND, some coarse sand, trace
gravel, trace silt; stratified (SP).
S-1
S-2
S-3
S-4
S-5
S-6
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/23/21,2/23/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
286
5
10
15
20
25
30
35
EB-16
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20213131
3333
4949
58
5050/6"
2929
Bottom of exploration boring at 21.5 feet
No groundwater encountered.
12
17
18
17
18
20
19
24
25
11
16
16
23
40
28
Asphalt - 3 inches
Fill
Moist, grayish brown, silty, fine SAND, some medium sand; contains
broken gravel; unsorted (SM).
Driller notes drill chatter.
Upper 6 inches consists of wood debris (mulch).
Lower 12 inches: moist, grayish brown, silty, fine SAND, some medium
sand, trace broken gravel; unsorted (SM).
Driller notes drill chatter.
Moist, grayish brown, silty, fine SAND, some broken gravel, some medium
to coarse sand; unsorted (SM).
Driller notes drill chatter.
Vashon Advance Outwash
Moist, grayish brown, fine to medium SAND, trace silt, trace coarse sand;
massive (SP).
Driller notes drill chatter.
Moist, grayish brown, fine to medium SAND, trace coarse sand, trace silt;
broken gravel (SP).
S-1
S-2
S-3
S-4
S-5
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/23/21,2/23/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
289
5
10
15
20
25
30
35
EB-17
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20213535
3838
4949
3232
68
Bottom of exploration boring at 31 feet
No groundwater encountered.
17
15
12
7
8
5
11
22
15
50/3"
23
22
26
50/6"
46
50/6"
Asphalt - 2 inches
Fill
Driller notes drill chatter.
Moist, dark brown, silty, fine to coarse SAND; contains asphalt in from
above; poor recovery (SM).
Driller notes drill chatter.
Moist, brownish gray, silty, fine SAND, some medium to coarse sand, trace
gravel (broken in tip) (SM).
Moist, grayish brown, silty, fine SAND to fine sandy, SILT, some medium to
coarse sand; massive (SM-ML).
Moist, brown, silty, fine SAND, some medium to coarse sand; broken
gravel in tip; poor recovery (SM).
Driller notes drill chatter.
Upper 12 inches: as above.
Vashon Advance Outwash
Lower 6 inches: moist, grayish brown, fine SAND, trace silt; occasional silty
interbeds; massive (SP).
No recovery, driller notes 3-inch sampler not likely to work due to gravel.
Driller notes drill chatter.
Moist, grayish brown, silty, fine SAND, some broken gravel, some medium
to coarse sand (SM).
S-1
S-2
S-3
S-4
S-5
S-6
S-7
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/23/21,2/23/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
290
5
10
15
20
25
30
35
EB-18
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 20212727
1313
3737
5050/3"
4848
5050/6"
5050/6"
Bottom of exploration boring at 36.5 feet
No groundwater encountered.
40
43
49
21
41
43
12
19
31
23
35
34
12
21
26
16
30
33
23
35
45
19
25
31
19
24
26
25
43
50/5"
25
32
30
Grass / Topsoil - 6 inches
Fill
Driller notes drill chatter.
Moist, grayish brown, silty, fine to medium SAND, some coarse sand,
some broken gravel; unsorted (SM).
Driller notes drill chatter.
Upper 12 inches: moist, reddish brown, fine sandy, SILT, trace coarse
sand; massive (ML).
Lower 6 inches: moist, grayish brown, silty, fine SAND, some medium to
coarse sand, trace broken gravel; unsorted (SM).
Driller notes drill chatter.
Moist, gray, gravelly, fine to medium SAND, some silt (SP-SM).
Vashon Advance Outwash
Driller notes change in drill action.
Moist, brownish gray, fine to medium SAND, some silt, some coarse sand;
sampler tip fell off causing most of the sample to fall in hole (SP-SM).
Moist, grayish brown, fine to medium SAND, trace silt, trace gravel;
massive (SP).
Moist, grayish brown, fine SAND, trace silt; occasional silty interbeds;
massive (SP).
Moist, grayish brown, fine to medium SAND, some coarse sand, trace silt;
massive; coarsens downward (SP).
Moist, grayish brown, fine SAND, trace silt; occasional silty interbeds;
massive (SP).
As above.
As above.
As above.
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
S-9
S-10
S-11
Exploration Boring
Water Level at time of drilling (ATD)
Olympic View K-8 School
M - Moisture
Project Number
20
Federal Way, WA
Date Start/Finish
CompletionLocation
Sheet
1 of 1
NAVD88
ART2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
Water Level ()Approved by:
30
Blows/Foot
SamplesDepth (ft)S
T
Exploration Number
20200286E001
2/23/21,2/23/21
Logged by:
Shelby Tube Sample
140# / 30
Boretec / EC-95 Track Mounted Drill
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8
40
Datum
Hammer Weight/Drop
Sampler Type (ST):
290
5
10
15
20
25
30
35
EB-19
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"JHS
AESIBOR 20200286E001.GPJ March 23, 202192
84
5050
69
4747
63
80
56
5050
5050/5"
62
APPENDIX B
Laboratory Testing Results
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 10.7 12.9 5.4 40.9 25.3 4.86 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-1 Depth: 0'
Client:
Project:
Project No:Figure
gravelly sand, trace silt
1-1/2"
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
94.4
89.3
84.9
83.2
80.6
76.4
72.2
71.0
59.1
30.1
12.7
7.4
4.8
3.9
NP NV NP
SP A-1-b
19.6229 15.9931 0.8759
0.6649 0.4244 0.2760
0.2105 4.16 0.98
10/09/2020 10/20/2020
NAS
ART/BG
10/07/2020
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 14.5 8.5 4.3 11.1 35.0 26.66 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-2W Depth: 5'
Client:
Project:
Project No:Figure
silty gravelly sand
1-1/2"
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
89.4
85.5
84.3
83.8
82.0
77.0
73.5
72.7
69.0
61.6
49.3
38.1
26.6
22.3
NP NV NP
SM A-2-4(0)
26.2005 17.9234 0.3921
0.2568 0.0951
10/09/2020 10/20/2020
NAS
ART/BG
10/07/2020
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 0.0 20.3 13.7 33.4 19.1 13.56 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-3 Depth: 10'
Client:
Project:
Project No:Figure
gravelly silty sand
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
97.2
94.1
90.5
79.7
68.9
66.0
51.4
32.6
22.8
18.1
13.5
11.5
NP NV NP
SM A-1-b
9.1845 6.5869 1.3549
0.8028 0.3802 0.0948
10/09/2020 10/20/2020
NAS
ART/BG
10/07/2020
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 12.1 31.6 13.2 18.1 13.4 11.66 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-4 Depth: 5-10'
Client:
Project:
Project No:Figure
very gravelly sand, some silt
1-1/2"
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
91.5
87.9
84.6
78.4
71.1
56.3
45.5
43.1
33.2
25.0
19.8
16.1
11.6
9.6
NP NV NP
SW-SM A-1-a
22.7346 16.1538 5.7777
3.2097 0.6472 0.1281
0.0568 101.74 1.28
10/09/2020 10/20/2020
NAS
ART/BG
10/07/2020
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 3.1 25.6 19.3 28.8 15.7 7.56 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-8 Depth: 10'
Client:
Project:
Project No:Figure
very gravelly sand, some silt
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
96.9
93.9
90.2
87.0
71.3
55.6
52.0
36.3
23.2
15.0
10.9
7.5
6.2
NP NV NP
SW-SM A-1-b
12.5382 8.3901 2.8940
1.8132 0.6086 0.2494
0.1277 22.66 1.00
10/09/2020 10/20/2020
NAS
ART/BG
10/08/2020
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 5.1 4.5 5.0 19.3 54.2 11.96 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-8 Depth: 15'
Client:
Project:
Project No:Figure
sand, some silt, some gravel
1-1/2"
1"
3/4"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
96.2
94.9
93.5
90.4
86.5
85.4
78.8
66.1
36.1
19.1
11.9
9.8
NP NV NP
SW-SM A-2-4(0)
4.3639 1.8857 0.3764
0.3177 0.2189 0.1138
0.0546 6.89 2.33
10/09/2020 10/20/2020
NAS
ART/BG
10/08/2020
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 0.0 9.6 12.0 52.0 19.3 7.16 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-9 Depth: 20'
Client:
Project:
Project No:Figure
SAND, some gravel, some silt
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
97.9
90.4
81.4
78.4
56.9
26.4
14.0
10.0
7.1
6.1
NP NV
SW-SM A-1-b
4.6010 3.0027 0.9235
0.7225 0.4666 0.2679
0.1506 6.13 1.57
02/25/2021 03/11/2021
NAS
ART/BG
02/22/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 5.8 6.9 6.7 33.3 37.8 9.56 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-10 Depth: 10'
Client:
Project:
Project No:Figure
gravelly SAND, some silt
1"
3/4"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
94.2
92.8
87.3
82.0
80.6
72.2
47.3
23.3
13.9
9.5
8.0
NP NV
SW-SM A-1-b
6.2675 3.5710 0.5696
0.4502 0.2968 0.1671
0.0838 6.79 1.84
02/26/2021 03/11/2021
NAS
ART/BG
02/22/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 4.1 22.3 8.0 37.1 19.8 8.76 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-19 Depth: 15'
Client:
Project:
Project No:Figure
gravelly SAND, some silt
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
95.9
93.9
87.3
82.7
73.6
67.2
65.6
52.0
28.5
16.7
12.3
8.7
7.3
NP NV
SW-SM A-1-b
13.8630 11.4328 1.2351
0.7942 0.4457 0.2159
0.0979 12.62 1.64
02/26/2021 03/11/2021
NAS
ART/BG
02/23/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 11.1 26.3 10.6 27.2 17.7 7.16 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-9 Depth: 15'
Client:
Project:
Project No:Figure
very gravelly SAND, some silt
1-1/2"
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
91.2
88.9
86.3
81.7
73.8
62.6
54.0
52.0
42.6
24.8
14.6
10.0
7.1
6.1
NP NV
SP-SM A-1-b
21.9896 14.8150 3.8330
1.6044 0.5169 0.2572
0.1506 25.45 0.46
02/25/2021 03/12/2021
NAS
ART/BG
02/22/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 3.0 17.4 11.9 39.4 18.3 10.06 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-11 Depth: 10'
Client:
Project:
Project No:Figure
gravelly SAND, some silt
1"
3/4"
1/2"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
97.0
94.2
79.6
69.8
67.7
55.2
28.3
17.9
13.9
10.0
8.2
NP NV
SW-SM A-1-b
8.9701 6.5616 1.0342
0.7330 0.4476 0.1779
0.0757 13.67 2.56
02/26/2021 03/12/2021
NAS
ART/BG
02/23/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 4.6 41.7 19.4 20.6 8.1 5.66 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-10 Depth: 15'
Client:
Project:
Project No:Figure
very gravelly SAND, some silt
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
95.4
91.1
82.9
76.2
53.7
37.6
34.3
21.4
13.7
9.8
7.7
5.6
4.9
NP NV
SW-SM A-1-a
15.3580 13.4896 5.7332
4.1779 1.5645 0.4855
0.2588 22.15 1.65
02/26/2021 03/12/2021
NAS
ART/BG
02/22/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 9.6 24.8 15.5 36.3 8.2 5.66 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: IT-1 Depth: 11+12'
Client:
Project:
Project No:Figure
very gravelly SAND, some silt
1-1/2"
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
95.0
90.4
88.8
83.8
79.3
65.6
52.9
50.1
33.3
13.8
8.8
7.4
5.6
4.9
NP NV
SP-SM A-1-a
18.0102 13.3831 3.5462
1.9901 0.7582 0.4507
0.3161 11.22 0.51
03/09/2021 03/18/2021
NAS
ART/BG/JHS
03/01/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 0.0 1.2 0.9 42.2 54.3 1.46 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: IT-2 Depth: 9'
Client:
Project:
Project No:Figure
SAND, trace silt, trace gravel
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
98.8
98.2
97.9
95.1
55.7
10.0
3.7
1.4
0.9
NP NV
SP A-3
0.7240 0.6466 0.4461
0.3995 0.3249 0.2714
0.2497 1.79 0.95
03/09/2021 03/18/2021
NAS
ART/BGJHS
03/02/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 33.8 23.4 7.4 20.3 12.2 2.96 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: IT-3 Depth: 14.5'
Client:
Project:
Project No:Figure
very sandy GRAVEL, trace silt
2"
1-1/2"
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
94.0
75.7
66.2
62.2
56.4
51.2
42.8
36.8
35.4
27.8
15.1
6.5
4.2
2.9
2.5
NP NV
GP A-1-a
34.3635 30.8720 14.5674
8.7733 1.0237 0.4224
0.3232 45.07 0.22
03/09/2021 03/18/2021
NAS
ART/BG/JHS
03/03/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 1.7 7.9 5.8 50.1 30.8 3.76 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: IT-4 Depth: 11+11.5'
Client:
Project:
Project No:Figure
SAND, some gravel, trace silt
1"
3/4"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
98.3
97.3
95.6
90.4
85.6
84.6
76.7
34.5
9.7
5.5
3.7
3.3
NP NV
SP A-1-b
4.5149 2.1496 0.6212
0.5350 0.3954 0.2945
0.2533 2.45 0.99
03/09/2021
NAS
ART/BG/JHS
03/04/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 10.2 19.4 10.0 46.8 12.1 1.56 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: IT-5 Depth: 11'
Client:
Project:
Project No:Figure
gravelly SAND, trace silt
1-1/2"
1"
3/4"
5/8"
1/2"
3/8"
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
96.9
89.8
85.8
83.0
79.6
70.4
62.4
60.4
46.4
13.6
3.8
2.2
1.5
1.4
SP
19.2233 15.0514 1.9265
0.9471 0.6021 0.4407
0.3788 5.09 0.50
03/09/2021 03/18/2021
NAS
ART/BG/KJS
03/05/2021
Federal Way School District
Olympic View K-8 School
20200286 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
APPENDIX C
Infiltration Test Data Sheets
Project Name: Water Source:4,000‐gal water truck
Project Number: Meter:NW Ex Meters (0.3‐3 and 3‐30)
Date: Pit Area (sq. feet):~6.3 x ~4.2 = ~26.5 sq ft
Weather: Ring Area (sq. feet):NA
Test No.: Test Depth (feet):10
Performed By: Receptor Soils:Advance Outwash
Time
(24‐hr) Flow Rate (gpm) Stage (feet) Totalizer (gallons) Comments
8:30 9.56 0.00 0 Flow on (3‐30)
8:45 6.34 0.72 111 Flow down
9:00 4.35 1.12 201
9:15 4.26 1.34 267 Flow down
9:37 3.28 1.41 345
9:46 3.28 1.42 371
10:00 3.38 1.45 418 Switched flow meter (0.3‐3)
10:18 2.66 1.50 464
10:30 2.68 1.46 493
10:45 2.71 1.46 535
11:00 2.74 1.46 573
11:35 2.72 1.44 668
11:45 2.70 1.42 707
12:18 2.74 1.42 785
12:30 2.76 1.42 817
12:45 2.79 1.42 862 Flow off/Mini falling head
12:49 0.00 1.38 862
12:57 0.00 1.30 862
13:06 0.00 1.18 862
13:26 2.45 0.98 862 Flow on (0.3‐3)
13:46 2.31 1.01 923
14:00 2.33 1.04 958
14:15 2.34 1.04 994
14:30 2.35 1.03 1034
14:40 2.32 1.04 1067
14:50 2.35 1.04 1105
15:00 2.31 1.04 1143
15:10 2.36 1.04 1173
15:20 2.31 1.04 1207
15:30 2.32 1.04 1243 Water off, begin falling head
15:40 0.92
15:50 0.69
16:00 0.43
16:10 0.32
16:20 0.18
16:30 0.04
last value used in falling head; begin dig
out.
Average Infiltration Rate (in/hr) during last hour of inflow: 12.6
Average Infiltration Rate (in/hr) during falling head: 12.0
Olympic View K‐8 School
20200286E001
3/1/2021
Overcast, 40's
IT‐1
ART
Associated Earth Sciences, Inc.
www.aesgeo.com
Olympic View K‐8
Federal Way, Washington
Project No. 20200286E001
Infiltration Test Data
Project Name: Water Source:4,000‐gal water truck
Project Number: Meter:NW Ex Meters (0.3‐3 and 3‐30)
Date: Pit Area (sq. feet):~3.5 x ~6.3
Weather: Ring Area (sq. feet):NA
Test No.: Test Depth (feet):9
Performed By: Receptor Soils:Advance Outwash
Time
(24‐hr) Flow Rate (gpm) Stage (feet) Totalizer (gallons) Comments
8:00 14.78 0.00 0 Flow on (3‐30gpm)
8:15 14.78 0.68 216 Flow down
8:30 7.02 0.48 314 Flow up
8:45 10.24 0.68 483
9:00 10.28 0.70 638
9:15 10.28 0.76 791 Flow down
9:30 9.08 0.72 924
9:45 9.70 0.72 1072
10:00 9.74 0.74 1215
10:15 9.74 0.76 1366 Flow down
10:30 9.52 0.76 1508
10:45 9.54 0.76 1650
11:00 9.58 0.80 1791
11:15 9.59 0.80 1933
11:30 9.59 0.80 2080
11:45 9.62 0.82 2225 Flow down
12:03 9.20 0.84 2399 Flow off/mini falling head
12:08 0.00 0.60 2399
12:10 0.00 0.50 2399
12:15 15.76 0.82 2512 Flow on (3‐30gpm)
12:33 9.34 0.82 2668 Flow down
12:45 9.32 0.82 2768
13:00 9.36 0.82 2907
13:15 9.32 0.82 3052
13:30 9.32 0.83 3186
13:45 9.36 0.83 3327
14:00 9.38 0.83 3462
14:10 9.36 0.83 3562
14:20 9.36 0.84 3657
14:30 9.38 0.86 3748
14:40 9.36 0.88 3842
14:50 9.36 0.90 3937
15:00 9.38 0.92 4071 Flow off/falling head
15:01 0.80
15:03 0.70
15:05 0.60
15:06 0.50
15:08 0.40
15:10 0.30
15:12 0.20
15:14 0.10 last reading used for falling head
15:15 0.00
Average Infiltration Rate (in/hr) during last hour of inflow: 43.3
Average Infiltration Rate (in/hr) during falling head: 42.2
Olympic View K‐8 School
20200286E001
3/2/2021
Overcast, 40's
IT‐2
ART
Associated Earth Sciences, Inc.
www.aesgeo.com
Olympic View K‐8
Federal Way, Washington
Project No. 20200286E001
Infiltration Test Data
Project Name: Water Source:4,000‐gal water truck
Project Number: Meter:NW Ex Meters (0.3‐3 and 3‐30)
Date: Pit Area (sq. feet):~3.4 x ~6.4
Weather: Ring Area (sq. feet):NA
Test No.: Test Depth (feet):14
Performed By: Receptor Soils:Advance Outwash
Time
(24‐hr) Flow Rate (gpm) Stage (feet) Totalizer (gallons) Comments
8:30 15.60 0.00 0 Flow on (3‐30gpm)
8:44 16.30 0.96 123 Flow down
8:50 4.50 1.06 163 Meter swapped (0.3‐3gpm)
8:53 1.43 1.08 167 Flow down
9:00 1.52 1.06 175
9:15 1.62 1.06 199
9:30 1.74 1.06 225
9:45 1.73 1.06 251
10:00 1.73 1.08 278 Flow down
10:15 1.04 1.08 293
10:17 1.04 1.08 296 Flow off/ mini falling head
10:30 0.00 1.02 296
10:45 0.00 0.93 296
10:57 0.00 0.86 296
11:00 1.01 0.86 296 Flow on(0.3‐3gpm)
11:17 1.03 0.84 312
11:30 1.03 0.85 324
11:45 1.08 0.85 340
12:00 1.08 0.85 357
12:30 1.08 0.85 388
12:45 1.06 0.86 405
13:00 1.05 0.86 420
13:15 1.06 0.86 437
13:30 1.06 0.87 453
13:45 1.07 0.87 468
14:00 1.01 0.88 487
14:15 0.98 0.88 500
14:30 0.98 0.89 514
14:40 0.98 0.89 522
14:50 0.96 0.89 532
15:00 0.98 0.89 541
15:10 0.97 0.89 551
15:20 0.98 0.89 561
15:30 0.98 0.89 572 Flow off/ falling head
15:35 0 0.86
15:40 0.83
15:45 0.81
15:50 0.78
15:55 0.76
16:00 0.73
16:05 0.70
16:10 0.66
16:15 0.63
16:20 0.59
16:25 0.54
16:30 0.51
Average Infiltration Rate (in/hr) during last hour of inflow: 4.3
Average Infiltration Rate (in/hr) during falling head:4.6
Olympic View K‐8 School
20200286E001
3/3/2021
Clear, 50's
IT‐3
ART
Associated Earth Sciences, Inc.
www.aesgeo.com
Oympic View K‐8
Federal Way, Washington
Project No. 20200286E001
Infiltration Test Data
Project Name: Water Source:4,000‐gal water truck
Project Number: Meter:NW Ex Meters (0.3‐3 and 3‐30)
Date: Pit Area (sq. feet):~3.2 x ~6.8
Weather: Ring Area (sq. feet):NA
Test No.: Test Depth (feet):11
Performed By: Receptor Soils:Advance Outwash
Time
(24‐hr) Flow Rate (gpm) Stage (feet) Totalizer (gallons) Comments
8:00 14.80 0.00 0 Flow on (3‐30gpm)
8:10 9.39 0.76 143 Flow down/minor caving
8:19 9.20 0.86 213 Flow down/minor caving
8:30 7.56 0.98 283 Flow down
8:45 6.43 1.00 381 Flow down
9:00 5.42 1.00 461
9:15 5.40 1.00 546
9:30 5.34 1.00 624
9:45 5.27 0.98 703
10:00 5.08 0.96 781 Flow off/ mini falling head
10:05 0.00 0.82 781
10:10 0.00 0.66 781
10:15 11.90 0.54 781 Flow on
10:23 11.90 1.00 851 Flow down
10:30 5.10 1.00 922
10:45 5.12 1.00 1002
11:00 5.04 1.00 1079
11:15 4.88 0.99 1155
11:30 4.65 0.96 1227
11:45 4.38 0.93 1294 Gravity fed flow slowing/pump on
11:50 13.26 0.98 1320 Flow down
12:00 5.15 1.00 1374
12:15 5.10 1.00 1449
12:30 5.10 1.00 1523
12:45 5.10 1.01 1601
13:00 4.98 1.01 1677
13:15 5.05 1.01 1753
13:30 5.02 1.01 1827
13:45 5.05 1.01 1903
14:00 5.01 1.02 1980
14:10 4.94 1.02 2029
14:20 5.05 1.03 2079
14:30 5.16 1.03 2131
14:40 5.08 1.03 2184
14:50 5.12 1.03 2235
15:00 5.06 1.03 2285 Flow off/ falling Head
15:03 0 0.95
15:06 0.89
15:08 0.81
15:10 0.76
15:13 0.65
15:16 0.58
15:19 0.47
15:20 0.4
15:21 0.32
15:24 0.23
15:26 0.15 last reading used in falling head
Average Infiltration Rate (in/hr) during last hour of inflow: 22.4
Average Infiltration Rate (in/hr) during falling head:24.4
Olympic View K‐8 School
20200286E001
3/4/2021
Overcast (Light PM Rain, 40's
IT‐4
ART
Associated Earth Sciences, Inc.
www.aesgeo.com
Olympic View K‐8
Federal Way, Washington
Project No. 20200286E001
Infiltration Test Data
Project Name: Water Source:4,000‐gal water truck
Project Number: Meter:NW Ex Meters (0.3‐3 and 3‐30)
Date: Pit Area (sq. feet):~3.2 x ~6.1
Weather: Ring Area (sq. feet):NA
Test No.: Test Depth (feet):11
Performed By: Receptor Soils:Advance Outwash
Time
(24‐hr) Flow Rate (gpm) Stage (feet) Totalizer (gallons) Comments
8:10 5.12 0.00 0 Flow on (3‐30gpm)
8:30 4.35 0.70 85
8:45 4.25 0.76 149 Flow down
9:00 3.61 0.70 205 Slight sloughing around staff guage
9:15 3.58 0.70 258
9:30 3.54 0.70 312
9:45 3.51 0.70 364
10:00 3.50 0.70 417 Flow off/ mini falling head
10:02 0.00 0.63 417
10:04 0.00 0.57 417
10:05 0.00 0.53 417
10:07 0.00 0.45 417
10:09 6.50 0.39 417 Flow on/ building head
10:15 5.57 0.82 469 Flow down
10:30 3.42 0.76 523 Flow up
10:45 3.96 0.78 583
11:00 3.94 0.80 642
11:15 3.92 0.80 701
11:30 3.90 0.80 758
11:45 3.90 0.80 819
12:00 3.90 0.78 877 Flow up/ building head ~1ft
12:15 5.22 0.92 955 Flow down/ slight caving
12:30 4.10 0.87 1020 Flow up
12:45 4.55 0.88 1086
13:00 4.52 0.88 1153
13:18 4.48 0.88 1240
13:30 4.48 0.89 1288
13:45 4.46 0.89 1356
14:00 4.45 0.89 1422
14:10 4.46 0.89 1467
14:20 4.45 0.89 1511
14:30 4.44 0.89 1553
14:40 4.46 0.89 1596
14:50 4.45 0.89 1642
15:00 4.47 0.90 1687
15:10 4.46 0.90 1731 Flow off/ falling head
15:13 0 0.86
15:17 0.72
15:20 0.64
15:24 0.53
15:27 0.41
15:30 0.26
15:33 0.13 last reading used in falling head
15:36 0.00
Average Infiltration Rate (in/hr) during last hour of inflow: 21.6
Average Infiltration Rate (in/hr) during falling head:24.1
Olympic View K‐8 School
20200286E001
3/5/2021
Light Rain, 40's
IT‐5
ART
Associated Earth Sciences, Inc.
www.aesgeo.com
Olympic View K‐8
Federal Way, Washington
Project No. 20200283E001
Infiltration Test Data
22
Appendix C
Operation & Maintenance Manual
(PENDING)
23
Appendix D
Conveyance Calculations and Exhibits
(PENDING)
24
Appendix E
Bond Quantities, Facility Summaries, and Declaration of Covenant
(PENDING)