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ENGINEERING REPORT
Technical In formation Report
Lindbergh Higfi School—Phase II
Permit Submittal
May 17,2012
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PREPARED FOR:
Renion School Disirid No.403
7812 S I 24`"Street
Seattle,WA 98178
(425) 204-4403
Conuct Rick Stracke
PREPARED THROUGH:
��� (�`. A McGranahan Architec�
�� 2 I I I Pacific Avenue #I 00
'A�.���
,�4 �g,�" ' `��fr ,� Tacoma,WA 98402
� �,� Phone:(253)383-3084
� �. Contact:Tom Marshall
� ������'���� w�
O��SSI�NAL E����� COUGHLINPo TERLUNDEEN
413 Pine Street,Suite 300
Seattle,Washington 98101
" P:206/343-0460
�L Contact: Keith Kruger, PE
35 � /
.
TECHNICAL INFORMATION REPORT
AND HYDROLOGIC ANALYSIS
Lindbergh High School Improvements
Coughlin Porter Lundeen Project No.C I I 0055-01
May 17,2012
TABLE OF CONTENTS
Section Page
I. PROJECT OVERVIEW.......................................................................................................................................1
GENERALDESCRIPTION....................................................................................................................................................... 1
EXISTINGCONDITIONS.......................................................................................................................................................2
PROPOSEDDRAINAGE SYSTEM.............................................................................................................................................2
11. CONDITION AND REQUIREMENTS SUMMARY....................................................................................4
KING COUNTY SURFACE WATER MANAGEMENT DESIGN MANUAL CORE REQUIREMENTS:.................................................4
SPECIALREQUIREMENTS:......................................................................................................................................................4
PROJECTSPECIFIC REQUIREMENTS:.......................................................................................................................................S
III. OFF-SITE ANALYSIS.........................................................................................................................................6
TASK I -$TUDY AREA DEFINITION AND MAPS....................................................................................................................6
TASK2-RESOURCE REVIEW................................................................................................................................................6
TASK3-FIELD INSPECTION.................................................................................................................................................6
TASK 4-DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS...........................................................................6
UPSTREAMANALYSIS...........................................................................................................................................................7
DOWNSTREAMANALYSIS....................................................................................................................................................7
TASK 5-MITIGATION OF EXISTING OR POTENTIAL PROBLEMS............................................................................................8
IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN...................1�
EXISTING SITE HYDROLOGY�PART A�............................................................................................................................... 1 O
DEVELOPED SITE HYDROLOGY(PART B�........................................................................................................................... 11
PERFORMANCE STANDARDS AND FLOW CONTROL SYSTEM�PARTS C AND D�................................................................. 14
SPILLCONTROL.................................................................................................................................................................17
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN.............................................................................19
STANDARD REQUIREMENTS�BASED ON KCSWDM AND SAO�:.......................................................................................l9
ON-SITE CONVEYANCE..................................................................................................................................................... 19
VI. SPECIAL REPORTS AND STUDIES............................................................................................................20
VII. OTHER PERMITS..............................................................................................................................................21
VIII. CSWPPP ANALYSIS AND DESIGN............................................................................................................22
STANDARDREQUIREMENTS...............................................................................................................................................22
IX. BOND QUANTITY, FACILITY SUMMARIES,AND DECLARATION OF COVENANT............23 '
X. OPERATION AND MAINTENANCE MANUAL.....................................................................................24
STANDARDMAINTENANCE...............................................................................................................................................24
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
11 Renton,�b'ashington
LIST OF FIGURES
Figure I —TIR Worksheet-Section I
Figure 2—Site Location-Section I
Figure 3 — Drainage Basins,Sub-basins,and Site Characteristics-Section I
Figure 4—Soils-Seccion I
Figure 5 —Off-Site Analysis Map&Table-Section 3
Figure 6—Floodplain/floodway FEMA Map-Section 3 II
Figure 7—Sensitive Areas Map-Section 3 '
Figure 8—Wetlands Inventory Map-Section 3
Figure 9—Designated Water Quality Problems Map-Section 3 �
Figure 10— F�cisting Site Hydrology-Section 4
Figure I I —Developed Site Hydrology-Section 4
Figure 12—Flow Control Applications Map-Section 4
Figure I 3 —Water Quality Applications Map- Section 4
LIST OF TABLES
Table I: Existing Site Area Conditions(North Basin)........................................................................................................10
Table 2: Existing Site Area Conditions(South Basin).........................................................................................................10
Table 3: North Basin Disturbed Area Conditions(Phase I).............................................................................................12
Table 4: North Basin Disturbed Area Conditions (Phase I I)............................................................................................12
Table 5: North Basin Flow Control Sizing Conditions and Water Quality Sizing.............................................................12
Table 6:South Basin Disturbed Area Conditions..............................................................................................................13
Table 7:South Basin Flow Convol Sizing Areas................................................................................................................14
Table 8: Summary of Flow Control Facilities Installed in Phase I.....................................................................................14
Table9a:Storm Facilities.....................................................................................................................................................15
Table 9b:Completed Phase I BMP Summary Table..........................................................................................................16
Table9c: Phase 2 BMP Summary Table..............................................................................................................................16
Table 10:Water Quality Treatment Areas........................................................................................................................17
Table I I: Summary of Water Quality System(Installed During Phase I)........................................................................17
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
lil Renton,Washington
I. PROJECT OVERVIEW
General Description
The following Technical Information Report(TIR) provides the technical information and design analysis required for
developing the Drainage and Temporary Erosion and Sedimentation Control Plan(TESC)for the Lindbergh High
School Improvemenu Phase I project. The storm water design for the project was based on the requiremenu set
forch in the 2009 King County Surface Water Design Manual (KCSWDM)as amended by the City of Renton (See
Figure I - Technical Information Report Worksheet).
The Lindbergh High School site is located within the City of Renton annexation area,located at 16426 128�'Avenue
SE(See Figure 2-Siie Location). The site is in Section 28,Township 23 North,Range 5 East,Willamette Meridian.
The Lindbergh High School site is approximately 37.3 acres.There are three existing school buildings,portable I
classrooms,play areas,hard surface tennis courts,sport fields,parking lots and associated support structures onsite
consisting of I 3.7 acres of impervious area and 23.6 acres of pervious area.
The culmination of the Lindbergh High School improvemenu will add staff parking,install new downspout connections
to the existing buildings,provide storm water detention and other drainage improvemenu,and modify surface
driveways and parking areas to accommodate school bus maneuvering.Only a portion of the school campus will be
impacted for this project.The buildings and sport fields will remain undisturbed throughout construction.A majority
of the existing utilities will also remain undisturbed except where necessary for new storm drainage installation or
grading activities. The total re-developed area will be approximately 9.8-acres.Two new detention systems will be
installed to mitigate peak flows from the redeveloped areas per the King County Surface Water Design Manual
(KCSWDM)as amended by the City of Renton.
Development has been broken out into two construction phases which will occur over two years to accommodate
the school schedule. Accordingly,a majority of the site improvements will occur during the summer months.This
report is written for the proposed Phase I I construction,slated to begin this summer.
Phase I was completed during the year of 201 I. It installed a new fire lane with staff parking along the east side of the
main school building,connecting the parking area located at north side of the school with the existing fire lane located
near the south side of the school;providing full fire access around the eastern portion of the building. Phase I drainage
improvemenu included new downspout connections to the existing building,an underground combined
detention/wet vault,and 60-inch diameter detention unks.The Phase I detention syscems have been sized to include
the final Phase 2 site conditions.
The enclosed Phase II plans will include the addition and replacement of paving and concrete walkways at the northern
(main) school entrance.The existing bus loop area will be modified to add parking stalls and provide a queuing area for
the buses.A new driveway will be installed to replace the existing northwest driveway to allow for easier wrning
movemenu from 128`�Avenue Southeast Also,new downspout connections will be provided to the existing building
roof drains.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
� Renton,Washingum
Existing Conditions
The existing Lindbergh High School site is approximately 37.36 acres,of which approximately 37%is impervious '�
ground cover.The project is located within the Lower Cedar River Drainage Basin,an area designated as a
Conservation Flow Control Area and Enhanced Water Quality Area by City of Renton code.The existing campus is
located on a ridge defining two separate onsite drainage basins which are dubbed the North Basin and the South Basin
for the purposes of this report
The North Basin drains to Renton storm lines located in SE I 64�'Street,which drains west through a closed-pipe
drainage system(for at least'/, mile downstream of the site)to an unnamed open channel conveyance system that
flows norchwest and discharges to the Cedar River and eventually Lake Washington. The South Basin drains to the
southeast corner of the property where it is routed co Molasses Creek downstream of Renton Park and Youngs Lake.
Development will occur in each basin triggering Level 2 runoff detention and enhanced water quality requiremenu for
all targeted and pollution generating impervious surfaces.
The site was previously developed with the existing Lindbergh High School campus.Storm drainage conveyance lines
ranging from 4-inches to 18-inches were previously installed in each basin for runoff conveyance.The Phase I project
installed a new fire lane,added surface parking,and drainage improvements.All new detention was installed during
Phase I construction,consisting of an underground combined detention/wet vault,and 60-inch diameter detention
tanks.The Phase I detention systems have been sized to include the final Phase 2 site conditions. Refer to Section 4
for a more thorough description of the existing conditions.
Proposed Drainage System
Site development will trigger runoff detention to the Level 2 Duration standnrd assuming existing"historic"(forested)
con ►bons. ater qu iq wi e provi e in t e ort m only since there are no proposed pollution generating
surfaces located in the South Basin.Storm water Best Management Practices(BMP's)are being provided where
practical to provide additional flow attenuation for targeted impervious surfaces.
Targeted impervious surfaces are defined as new impervious surFace.Replaced impervious surface will not be counted
because the value of the replaced impervious surfaces does not exceed 50°�of the existing site value per section
I.2.3.I.B of the City of Renton Surface Water Design Manual Amendmenu.
The project will utilize Permeable Pavement,and Basic Dispersion BMP's selected from Appendix C of the KCSWDM.
Flows generated from new impervious surfaces where it is not feasible to mitigate runoff through BMP's will be
compensated for by providing Basic Dispersion from existing impervious surFaces throughout the site.
North Basin
The North Basin is comprised of the northern entrance,staff parking,bus loop,gym building,and a majority of the
main school building.The existing storm system consists of underground storm conveyance pipes ranging form 4
inches to I 2 inches in diameter.A drainage swale is located along the northern boundary of the site that functions as a
collection system for all surface flows not captured in the storm drainage pipe system.The underground
detentionlwet vault and cartridge filter were installed during Phase I construction.
Detention and water quality has been provided via a combined underground detention/wet vault and a cartridge filter
located north of the school building.These have been designed to provide Basic Enhanced water quality in the North
Basin.The vault will be sized to account for the final project development(both phases I and 2). Flow control
calculations have been provided to account for the final site condition;see calculations in Section IV.
New storm water conveyance lines will be insralled to collect flows generated from the modified bus loop area.
French drains and new downspout connections will be added west side of the existing gym building.The majority of
flows from the existing building will bypass the new underground detention/wet vault since it is non-target area. Refer
to Section IV for more information on the flow control and water quality analysis and design.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu I
2 Rencon,Washington I
South Basin
The South Basin is comprised of the student parking area,multiple sport fields, hard surface tennis courts,and existing
building area.The existing storm conveyance system consists of underground storm conveyance pipes ranging form 4
inches to 18 inches in diameter.
During Phase 2 the drainage in the student parking area located in the southwest portion of the site will be replaced.
No new impervious surface associated with the drainage improvements are anticipated at this time.
Detention for Phase I improvemenu has been provided via underground detention tanks consisting of 60-inch
diameter pipes located south of the school building. French drains and new downspout connections will be added
along the south side of the building improve drainage in wet areas surrounding the building. Refer to Section IV for
more information on the flow control and water quality analysis and design.
COUGHLINPORTERLUNDEEN Lindbergh High$chool Improvemenu
3 Renton,Washington
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND
PROJECT ENGINEER DESCRIPTION
Project Owner: Renton School District No. 403 Project Name: Lindbergh High School
Phone:425 204-4403 Improvements
Address: 7812 S 124'"St. DDES Permit#: Not available at this bme
Seattle, WA 98178 Location: Township 23 N
Project Engineer: Keith Kruger, P.E. Range 5 E
Company Coughlin Porter Lundeen, Inc Section 28
Phone: 206 343-0460 Site Address: 16426 128"'Ave SE
Renton,WA 98178
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
❑ Landuse Services ❑ DFW HPA ❑ Shoreline
Subdivison / Short Subd. / UPD ❑ COE 404 Management
❑ Building Services ❑ DOE Dam Safety Structural
M�Commerical / SFR R keryNault/
Clearing and Grading ❑ FEMA Floodplain
❑ ESA Section 7
❑ Right-of-Way Use ❑ COE Wetlands
❑ Other � Other_NPDES
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review Full / Targeted / Type(circle one): Full / Modified /
(circle): Large Site Small Site
Date(include revision Date(include revision
dates): dates):
Date of Final: Date of Final:
Part 6 ADJUSTMENT APPROVALS
Type(circle one): Standard I Complex / Preapplication / Experimental/ Blanket
Description: (include condfions in TIR Section 2)
NA
Date of A roval:
2005 Surface Water Design Manual 1/1/05
FIGURE 1 -TIR Worksheet
Part 7 MONITORING RE�UIREMENTS
Manitoring Required: Yes I No Describe: Per NPDES Requirements
Start Date:
Comple6on Date:
Part S SITE COMMUNITY AND DRAINAGE BASIN
Community Plan :
Special District Overlays:
Drainage Basin: Lower Cedar River
Stormwater Requirements: Level II Detention, Basic Water
Qualiry
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
❑ River/Stream ❑ Steep Slope
❑ Lake ❑ Erosion Hazard
�Wetlands ❑ Landslide Hazard
❑ Closed Depression ❑ Coal Mine Hazard
❑ Floodplain ❑ Seismic Hazard
❑ Othe� ❑ Habitat Protection
❑
Part 10 SOILS
Soil Type Slopes Erosion Potential
AgC 2-30% Moderate to severe_
❑ High Groundwater Table(within 5 feet) ❑ Sole Source Aquifer
❑ Other ❑ SeepslSprings
❑ Additional Sheets Attached
2005 Surface Water Desi Manual 1 1 05 !
gn / /
FIGURE 1 -TIR Worksheet
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE LIMITATION/SITE CONSTRAINT
❑
❑
❑
❑
❑
❑ Additional Sheets Attached
Part 12 TIR SUMMARY SHEET rovide or�TIR Summa Sheet Threshold Discha e Area
Threshold Discharge Area:
name or descri tion
Core Requirements(all 8 apply)
Dischar e at Natural Location Number o atural Dischar e Locations:
Offsite Analysis Level: / 2 / 3 dated: 2�- ?.al 4
Flow Control Level: 1 / 2 3 or Exemption Number
incl. facili summa sheet Small Site B s
Conveyance System Spill containment located at: rj�
Erosion and Sediment Control ESC Site Supervisor: -r�D
Contact Phone:
After Hours Phone�
Maintenance and Operation Responsibility: rivate / Public
If Private, Maintenance Lo R uired: Yes /No
Financial Guarantees and Liabil� Provided: Yes / No
Water Quafity Type: Basic / Sens. Lake I Enhanced Basicm / Bog
(include facility summary sheet) or Exempti o.
Landsca Mana ement Plan: Yes / No
S ecial R uirements as a licable
Area Specific Drainage Type: CDA/SDO/MDP/BP/LMP/Shared Fac. Non
Re uirements Name:
Floodplain/Floodway Delineation Type: Major / Minor I Exemption / one
100-year Base Flood Elevation(or range):
Datum:
Flood Protection Facilities Describe:
Source Control Describe landuse:
(comm./industrial landuse) Describe any structural controls:
2005 Surface Water Design Manual 1/1/05
FIGURE 1 -TIR Worksheet
Oil Contral High-use Site: Yes / No
Treatment BMP:
Maintenance Agreement: Yes / No
with whom?
Other Draina e Structures
Describe:
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTTON AFTER CONSTRUCTION
� Clearing Limits � Stabilize Exposed Surfaces
� Cover Measures ,�Remove and Restore Temporary ESC Facilities
� Perimeter Protection �Clean and Remove All Silt and Debris Ensure i�
r� Operation of Permanent Facilities
!CI Traffic Area Stabilization
❑ Flag Limits of SAO and open space preservation
� Sediment RetenGon areas
� Surface Water Control ❑ Other
� Dust Control
Construction S uence
Part 14 STORMWATER FACILITY DESCRIPTIONS Note: InGude Facil� Summa and Sketch
Flow Control Type/T)escription Water Quality Type/Description
� Detention Underground Vault ❑ Biofiltra6on
❑ Infiltration �-Wetpool �p��
V�¢uy
❑ Regional Facility ❑ Media Filtration
❑ Shared Facility ❑ Oil Control
❑ Small Site BMPs ❑ Spill Control
❑ Other ❑ Small Site BMPs
❑ Other
2005 Surface WaEer Design Manual 7/1/OS
FIGURE 1 -TIR Worksheet
Part 15 EASEMENTSITRACTS Part 16 STRUCTURAL ANALYSIS
❑ Drainage Easement �Cast in Place Vauft
❑ Access Easement Retaining Wall
❑ Native Growth Protection Covenant ❑ Rockery>4' High
❑ Tract ❑ Structural on Steep Slope
❑ Other ❑ 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 Repo�t. To the best of my
knowledge the infoRnation provided here is accurate.
s � C. �/� 5_,�_2�,2
s ►��er�
2005 Surface Water Design Manual 1/1/05
_ Figure 2 - Site Location
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COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
Figure 3 — Drainage Basins, Sub Basins and Site Characteristics
_ _
__ _
�J North Basin Point �
of Dischar e "
_T 9
Combmed Wet
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_ � ___ _ ___ _ _ _._ � _ _ _ _ _ _ _ _ ;
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
Figure 4 - Soils Map
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, COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
�_ ' Renton,Washington �i
II. CONDITION AND REQUIREMENTS SUMMARY
This section will address the requiremenu set forth by the Core and Special Requirements listed in Chapter I of the
KCSWDM.
King County Surface Water Management Design Manual Core Requirements:
I. Discharge at the Natuml Location(1.2.1):6cisting site discharge points in the northwest and southeast
corners of the site will be maintained and used for this project
f_
2. Of f-site Analysis(/.2.2):A Level 2 downstream analysis has been performed,see Section III.
� 3. Flow Control(1.2.3):Refer to Section IV.The site has been divided into two sub basins dubbed the North Basin
and the South Basin. Detention has been provided to the Level 2 Flow Control standard, per KCSWDM as
' amended by the City of Renton.An underground detention vault will be installed in the North Basin;and an
underground 60-inch diameter detention pipe system will be installed in the South Basin.
4. Conveyance System(1.2.4): Refer to Section V. Closed pipe systems and conveyance channels have been
- provided for on-site stormwater conveyance.The pipe sizes have been designed based on the proposed flow
conditions.Conveyance calculations are included in Section 5.
5. Erosion and Sedimentation Control(1.2.5): Refer to Section VIII.The site will provide Construction
Stormwater BMP's to meet the construction runoff standard equal to or greater than the Department of Ecology
standard.An erosion control plan will be provided with the site development permit submittal.
6. Maintenance and Operations(1.2.6): Refer to Section X.The proposed storm drainage system will be owned,
operated and maintained by the owner.
7. Financial Guarontees and Lia6ility(1.1.7):Refer to Section IX The owner and contractor will obtain all
necessary permiu prior to the beginning of construction. The Renton School District,as a public agency, is not
required to provide bonds.
8. Water Quality(1.2.8):Refer to Section IV.E. Enhanced water quality treatment will be provided by a
combination of dead storage in the combined detention/wet vauk and a CSF cartridge filter located in the North
Basin.
Special Requirements:
Special Requirement#I. Other Adopted Area-Specific Requiremenu Section I.3.I ,
• Critical Drainage Areas(CDAs):There are(4)wetlands on site which will remain unaffected during '
construction.
• Master Drainage Plans(MDPs): Not Applicable. '
• Basin Plans(BPs):Cedar Geek Basin. ',
• Lake Management Plans(LMPs): Not Applicable. �,
• Shared Facility Drainage Plans(SFDPs): Not Applicable. �I
Special Requirement#2. Flood Hazard Area Delineation,Secuon I.3.2: Not Applicable ��I
Special Requirement#3. Flood Protection Facilities,Section I.3.3: Not Applicable
Special Requirement#4. Source Controls,Section I.34:There are no proposed surfaces that will require source
control.
Special Requirement#5. Oil Control:Traffic will be limited to passenger vehicles and busses typical of school sites.
Basic water quality will be provided via dead storage which is an approved method of treatment for the
anticipated pollutanu.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
4 Renton,Washingcon
Project Specific Requirements:
There are no additional requiremenu for this portion of the project Design and construction will abide by
requirements set forth in these documenu and King Counry as amended by the City of Renton.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
5 Renwn,Washington
II1. OFF-SITE ANALYSIS
Task 1 -Study Area Definition and Maps
The study area was mapped using the King County GIS iMAP tool (See Figure 5 -Of f-Site Analysis Map& Table).
Task 2-Resource Review
a) Adopted Basin Plans Cedar Creek Drainage Basin
b) Floodplain/floodway(FEMA) Maps Not in 100-yr floodplain (See Figure 6)
c) Off-site Analysis Reporrs None available
d) Sensitive Areas Folio See Figures 7
e) Drainage Complaints and Studies See Figure 8
� Road Drainage Problems Not available
g) King Counq Soils Survey: See Figure 4
h) Wetland Inventory Maps: See Figure 9.
i) Migrating Rivers Study Not available
j) DOE's Secti�n 303d List of Polluted Waters Lake Washington
k) KC Designated Water Quality Problems Not Available
I) Critical Drainage Area Maps: Not in Critical Drainage Area.
Task 3 - Field Inspection
A preliminary site visit to perform a Level I Downstream Analysis took place February 2,201 I.The analysis was
provided for review during the preliminary SPR review. Since then,another site visit was completed on April 22,201 I
to follow up with a Level 2 Downstream Analysis. Refer to Task 4,Downstream Analysis below for more information.
Task 4- Drainage System Description and Problem Descriptions
Site elevations vary widely across the site;a majority of the site was previously graded from the natural condition for
the existing high school campus infrastructure.The highest portions of the site are located in the southwest and
northeast corners of the site near elevation 435 feet to 437 feet respectively.Grades fall towards the northwest and
southeast corners of the site where elevations are approximately 368 and 386 respectively.The greatest difference in
elevation is approximately 69 feet with the lowest elevation being in the northwest corner of the site.
The existing campus is located on a ridge defining two separate onsite drainage basins which are dubbed the North
Basin and the South Basin.The North Basin drains to Renton storm lines located in SE I 64�'Street,which drains west
through a closed-pipe drainage system(for at least'/+ mile downstream of the site)to an unnamed open channel
conveyance system that flows to the northwest and discharges to the Cedar River and eventually Lake Washington.
The South Basin drains to the southeast corner of the property where it is routed to the Molasses Creek
downstream of Renton Park and Youngs Lake.The drainage path for this site is a combination of sheet flow and closed
pipe conveyance. '
On-site soils are classified as AgC per King County Soil Survey maps(See Figure 4).Generally,soils are above the '
i optimum moister levels,see geotechnical report in Section VL(Subsurface Exploration,Geologic Hazards,and '
�_ Preliminary Geotechnical Engineering Report. Renton,Washington. Prepared by Associated Earth Sciences,Inc.on
February I6,2010). I
� I
I
- COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
6 Renton,Washington
Upstream Analysis
The upstream areas contributing to surface runoff are limited on the site to the southern property line located within
the Southern Basin where topography suggesu that some surface runoff is introduced from the adjacent parcel
currently developed as the Renton Park Chapel Evangelical Church and private residential parcels to the paved student
parking area and the hard surface tennis court area. Runoff generated from the upstream parcels would be collected in
the existing site storm pipe system and conveyed to the southeastern corner of the propercy.The project will
propose to collecc runoff from upsu-eam areas and bypass all detention proposed by this project as is the existing
condition.
Downstream Analysis
As described above the existing site topography contains a ridge with grades ultimately falling to the northwest and
southeast corners of the site.The ridge line dividing the site and existing storm conveyance system insulled during
pasc developments separates the site into two drainage basins,dubbed the North Basin and the South Basin for this
project Both basins flow towards the Cedar River and ultimately discharge to Lake Washington.
The flow path of each basin downstream was walked for not less than one quarter mile to observe potential hazards
and impacts of new development to the existing conveyance rystem.A preliminary Level I downstream analysis was
performed on February 2,201 I,during a period of clear weather yielding approximately 42° F temperatures.Special
attention was given around properties with registered drainage complainu,documented by King County,viewed on
the King County Imap webpage.
The preliminary Level I downstream analysis was submitted to the City for review.Subsequently,a follow up site visit
was performed on April 22,201 I to provide additional information through a Level 2 downstream analysis.The
weather at the dme of the site visit was overcast,no rain,with temperatures in the mid 50's(° �.The site visit
followed a period of moderate rainfall.
The following is a Level 2 description of the downstream encounter and analysis of potential site impacts of the North
and South Basins.
North Basin
The North Basin has two discharge points from the site to the Renton storm conveyance lines located in I 28�'Avenue
SE;one storm line located under the northern entrance,and one inlet pipe that collecu runoff from a swale located
along the northern property line. It is noted that limited pervious areas of the site sheet flows to the I 28`"Street SE
right-of-way.These areas will not be altered as a resuk of this project Runoff generated from the developed basin
area currently leaves the site without detention.
The runoff flows in a northerly direction in I 28`�'Street SE in 12-inch diameter concrete storm line for approximately
I 20 feet until it reaches the intersettion of I 28�'Street SE and SE I 64`"Street,where it joins the westerly flowing 24-
inch diameter concrete storm line at a manhole located in SE I 64"'Sveet. Runoff flows westerly in SE I 64�'Street for
approximately 700 feet to a manhole at the intersection of SE I 64�'Street and I 27`t"Avenue SE where it turns north.
The 24-inch diameter concrete pipe was observed to have approximately 2 to 3 feet of cover and roughly follow the
sueet grades west The conveyance system continues north on I 27`''Avenue SE for approximately 250 feet where it
takes a 90 degree turn to the west at a manhole located in the sueet.The 24-inch diameter storm line flows west for
another 100 feet under two residential propercies to a manhole located in I 26`"Avenue SE and then to another
manhole located in on the edge of Cascade Park.The 24-inch diameter concrete pipe was observed to be
approximately 4 feet deep at the Cascade Park manhole. Runoff continues north through the park beyond the quarter
mile downstream area.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
7 Renton,Washington
;-� �
i
South Basin
Portions of the South Basin are sloped in such a way that runoff sheet flows offsite to the east Runoff from these
areas is considered pervious,undeveloped and will not be akered as a result of this project.The eacisting storm
conveyance lines onsite bring runoff around the existing track to the southwestern corner of the property where
storm lines flow east ofFsite between adjacent neighboring parcels to the storm system located in I 32'�Place SE.
Runoff generated from the developed portion of the South Basin currently discharges from the site un-detained from a
manhole located in the southeast corner of the site through a I 5-inch diameter corrugated metal pipe(CMP)with
approximately 3 feet of cover.The pipe conveys site runoff east approximately 205 feet through "Tract E",located
between two residences,to a catch basin located in the west flow line of t 32 Place SE.At that catch basin another I 5-
inch diameter CMP,approximatety 3.5 feet deep,flows 35 feet to the eastern flow line in 132 Place SE.A vertical CMP
flow control structure was observed in the manhole located on the eastern flow line of 132 Place SE. No signs of
detention were observed under the street other than the 35 feet of I 5-inch diameter CMP that preceded the
manhole.After the flow control structure runoff continues east in a I S-inch diameter CMP approximately 3.5 feet
deep between two residences for approximately 135 feet where it outfalls in a narrow rock lined swale to the
Molasses Creek.
The Molasses Creek originates at Lake Youngs and flows in a northerly direction through Renton Park and then
through residential properties where the outfall from the Lindbergh High School site is located. At the outfall to
Molasses Creek the channel varies from 3 to 5 feet wide at the base with a flow depth of approximately I 2-inches.
The Creek flow north for approximately 390 feet to SE I 66 Place where it flows under the street in a 48-inch
diameter CMP.
The Creek daylights on the north side of SE 166 Place and continues is a 3 to 5 feet wide channel flowing
approximately I 2-inches deep for approximately 390 feet to a 30-inch diameter inlet pipe located on private property.
The pipe immediately joins a 72-inch diameter manhole.Another 48-inch diameter CMP was observed continuing
north underground for approximately 75 feet to another 72 inch diameter manhole.The 48-inch diameter CMP varied
in depth from approximately 9 feet deep on the uphill side to approximately 14 feet deep on the downhill side. Runoff
continues north for approximately I 20 feet in the 48-inch diameter CMP through an un-named park area to a fenced
right-of-way easement culminating the'/, mile downstream distance.F�chibits have been added at the back of Section III
showing a diagram of the downsveam condition.
Task 5 -Mitigation of Existing or Potential Problems
North 8asin ,
There are three registered drainage complaints located within the quarter mile downstream distance,shown on the ',
King County Imap.The addresses where the complaints originated are 12615 SE 164�'Street, I 6308 I 26�'Avenue SE, I
and I 6162 I 26�'Avenue SE.The nature of the drainage complaints is not disclosed on the Imap website.There were I,
no observed signs of flooding or drainage obstructions during the downstream analysis. Runoff is contained in Renton �,
storm lines for the duration of the quarter mile downstream.The project is located in a Conservation Flow Control
Area and will apply the historic site conditions Level 2 Flow Control standard;therefore, no additional flow control is
needed per section I.2.2.2 and Table I.2.3.A of the KCSWDM.
South Basin
There are multiple documented draina,ge complainu registered at residenval parcels adjacent to the Molasses Creek
contained within the quarter mile downstream area.The complainu have originated from addresses at I 3215 SE 166�'
Place, I 3214 SE 166�'Place, 16525 133`' Place SE, I 6524 I 32"d Place SE, I 6513 I 33'�Place SE,and 16519 I 33'� Place
SE.The nature of the complaints has not been disclosed on the King County Imap website. Speculation can be made
based on visual observations that the Molasses Creek is capable of overtopping iu narrow channel width to an
unspecified depth.The portions of Molasses Creek observed with adjacent residential parcels were lower in elevation
than the neighboring yards,delineated by fences. It is thought that the creek can overFlow the normal channel by a few
feet without flooding or damaging adjacent residential parcels.Since the majority of the runoff flowing through
COUGHLINPORTERLUNDEEN Lindbergh High SChool Improvements
6 Renton,Wuhington
Molasses Creek originates from Lake Youngs the project site will have negligible impacu to the Creek levels.New
detention systems are proposed on site which should reduce peak flows to Molasses Creek.The downstream has
been classified as a Type I Conveyance System Nuisance Problem.The project is located within a Conservation Flow
Control Area and is providing Level 2 Flow Control for all targeted impervious surfaces;therefore,it has been
determined that the project will not significantly contribute to the existing drainage issues. No additional flow control
is needed per section 1.2.2.2 and Table 1.2.3.A of the KCSWDM.
' I
;
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
9 Renton,Washington
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COUGHLINPORTERLUNDEEN
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COUGH LI NPORTER W NDEEN Lindbergh High School Improvements '
Renton,Washington ,
Figure 7 — Sensitive Areas Map
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COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
Figure 8 — Drainage Complaints Map I
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COUGHLINPORTERLUNDEEN Lindbergh High School Impmvements
Renton,Washington
Figure 9 — Wetlands Inventory Map
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COUGHLINPORTERLUNDEEN Lindbergh High School Improvements I
Renton,Washington
IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
Existing Site Hydrology(Part A)
The existing Lindbergh High School site,prior to Phase I,is approximately 37.36 acres,of which approximately 37%is
impervious ground cover. There are three existing school buildings,two storage buildings,multiple portable
classroom buildings,sport fields,hard surface tennis courts,paved parking lots and walkways,and associated support
I' ,_ struccures onsite. (See Section 4,Figure I I -Exisring Site Hydrology).A summary of the existing site cover
'� !
characteristics are shown below in tables I and 2.
Table 1:Existin Site Area Conditions North Basin
Area acres
Roof Area 2.98
Paved Walkwa and Drivin Surfaces 5.72
Pervious I 2.90
Total Basin 18.41
Table 2:Existin Site Area Conditions Souih Basin
Area acres
Roof Area I.20
Paved Walkwa s and Drivin Surfaces 3.17
Field 3.20
Pervious I I.38
Total Basin 18.95
The site is located within the Lower Cedar River Drainage Basin,an area designated as a Conservation Flow Control
Area and Enhanced Water Quality Area by the City of Renton code.There are no known designated landslide hazard
zones or flood plains zones located onsite.
Site elevations vary widely across the site;a majority of the site was previously graded from the natural condition for
the existing high school campus infrastructure.The highest portions of the site are located in the southwest and
northeast corners of the site near elevation 435 feet to 437 feet respectively. Grades fall towards the northwest and
southeast corners of the site where elevations are approximately 368 and 386 respectively.The greatest difference in
elevation is approximately 69 feet with the lowest elevation being in the northwest corner of the site.
Slopes are generally mild across walking surfaces,driving surfaces,and sport fields.Some limited steeper slopes are
located in between sport fields in the southern portion of the site; likely a result of previous grading activity.These
slopes are generally sloping between 2:I to 3:I (horizontal to vertical).Other steeper slopes are located along the
eastern boundary of the site,sloping around 2:1 to the east where neighboring properties are situated.
The current conditi�ns at the northeast corner of the site are sloped towards the existing building in mild to steep �
slopes ranging from 2%to 5%on the mild side up to 3:I in the steeper areas.The two sport fields located in the �
northwest portion of the site are terwaced with approximately 25 feet of elevation difference separated by a slope of
approximately 3:I in the steepest areas.The existing cut slopes onsite are not anticipated to be subject to critical zone
regulations,per geotechnical report published by Associated Earth Sciences,dated February 18,2010.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
�� Renton,Washington
Soil Conditions
Regional soil maps reviewed by Associated Earth Sciences show that the native surface material in the vicinity
containing the project site are classified as lodgement till;however,subsurFace borings performed by Associated Earth
Sciences, Inc.showed that some areas of the site contained 8 feet t� I 3 feet of fill material (considered to be from
past grading activities)overlaying Ice Contact Deposiu consisting of siky sand with gravel interbedded in places with
fine sand zones or silt stems.Some lodgement till was encountered in areas below the layer of ice contact deposiu,
see Figure 4-Soils.
Areas of the site near the lowest northwest corner contain varying levels of ground water attributed to interflow
stemming from a perched water table.The water table was documented to be I 0 feet to I 5 feet below existing grade
but is anticipated to fluctuate with the season and weather conditions. (Since construction will occur during the
summer months, no formal construction dewatering plans will be submitted;the contractor will be advised of this
possibility and have the necessary equipment to mitigate perched ground water isolated areas as required).
Based on the analysis by Associated Earch Sciences and observations of existing surface conditions;for the purpose of
runoff calculations,the project will be characterized as Soil Class`C'with poor potential for onsite infiltration.The
Subsur face Explora[ion,Geologic Hazards,and Preliminary Geotechnical Engineering Re¢ort prepared by Associated Earth
Sciences for the Renton School District,dated February I 8,2010,has been included in Section 6 of this report,and
contains a more thorough examination of existing soil conditions.
This site is located in Groundwater Protection Area. Per Section I.2.4.H,ground water protection requirements
apply to sites with outwash soils.This site has Alderwood Soils,which is classified as Till per Table 3.2.2.B of the 2009
KCSWDM. Therefore no groundwater protection facilities are required for this site.
Developed Site Hydrology(Part B)
Runoff from the new development requires Level 2 runoff detention requirements for all targeted impervious surfaces.
Additionally,Enhanced Water Quality will be triggered in the North Basin.A study of the existing site topography and
the existing storm infrastructure was completed to define the existing basin boundaries;drainage patterns onsite will
not be greatly altered as a resuk of this project.The existing discharge points in the northwest and southeast corners
of the site will be maintained and re-used for this project.
Stormwater Best Management Practices(BMP's)are being provided for targeted impervious surfaces per City of
Renton Surface Water Design Manual Amendmenu.Stormwater BMP's will be designed per Appendix C of the 2009
KCSWDM. Design calculations and tables have been included at the back of this section,also see Figure I I b.Targeted
impervious surfaces are defined as new impervious surFace. Replaced impervious surface will not be counted because
the value of the replaced impervious surfaces does not exceed 50%of the existing site value per section I.2.3.I.B of
the City of Renton Surface Water Design Manual Amendmenu.
North Basin
The North Basin is comprised of the northern entrance,staff parking, bus loop,gym building,and a majority of the
main school building.The Phase I improvements include the northern portion of the fire lane and added staff parking
that connects the northern surface parking area around the east side of the school to the fire lane on the south side of
the school.The addition of the fire lane and staff parking will add approximately 0.59 acres(25,826 sfl of impervious
surface which will trigger flow control and water quality requirements.
The total disturbed area(new+ replaced)at the culmination of Phase 2 is anticipated to be approximately 3.5 I-acres.
In Phase 2 the mounded area currentty planted with grass,trees,and shrubs located within the bounds of the bus loop
will be graded and new parking and widened bus queuing area will be added in its place.Tables 3 and 4 summarize the
development in the North Basin for both construction phases. '
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu I
� � Renton,Washington
Table 3:North Bosin Disturbed Area Conditions Phase 1
New Area acres Replaced Area(acres)
0.59 (26,d05 sf of BMP 0.I I
Parkin lot and drive aisle Treatment Re uired
Pedesvian Walkwa s
Pervious I.00
Total Basin hase I 1.59 0.1 I
Table 4:North Basin Disturbed Area Conditions Phase 11
New Area acres Replaced Area(acres)
0.30(I 3,068 sf of BMP 0.3 I
Parkin lot and drive aisle Treatment Re uired
Pervious 0.90 0.30
Total Basin hase 2 1.20 0.61
Detention has been provided via combined underground detention/wet vault located north of the school building;
water qualiq will be provided by the combination of the detention/wet vault and a CSF cartridge filter system located
in the north parking I�t These facilities will be sized to account for the final project development and will provide
Basic Enhanced water quality.
French drains and new downspout connections will be added along the west side of the existing gym building and
within the main school entrance.The majority of flows from the existing building will bypass the new detention and
water quality rystems.Only the new impervious surfaces have been used for flow control sizing as previously
described.
Some areas of new(target) impervious surface will be lower in elevation relative to the detention vault location.Area
swaps of exisung surface(non-target)areas are proposed in this situation,see Figure I I a.Specifically,the Phase 2
grading of the bus loop area will not flow through the combined detention/wet vault.An equal or larger area of the
existing paved area north of the building will be collected and detained in lieu of the bus loop area.
PARTIAL CREDIT HAS BEEN TAKEN FOR THE STORMWATER BMP'S IN THE NORTH BASIN.The upper parking I'
area contains approximately 14,437 sf of which 50%credit has been taken for the stormwater sizing. No other flow I
control credit has been assumed for the detention sizing.A figure showing the location of stormwater BMP's is shown ',
at the back of Section IV.The final site conditions used for detention and water quality sizing are shown in Table 5 !�
, below. '�
Table 5:North Bosin Flow Control Sizin Conditions and Water ualit Sizing �
Area acres
6cistin Im ervious Non Tar eted Im ervious 0.250 i
Existin Pervious Non Tar eted Pervious 0.313
New Im ervious Surface or eted I ervious 0.732
New Pervious Surface ar eted Pervious 2.065
Total Mrti oted 1 ervious =0.982
Total Miti ated Pervious 2.378
Total Miti ated Area 3.360 AC
The detention faciliry has been designed to provide runoff flow control to the Level 2 Flow Control standard,
designated by the KCSWDM.The pre-developed forested condition has been assumed for all new targeted impervious
surfaces;existing impervious such as roof area,replaced paving,and areas that will have an asphalt pavement overlay
are assumed to be impervious in the pre-developed flow control calculations(See Figure 3 -Droinage Bosins,Sutrbasins,
and Site Characteristics and Section 4, Figure I 2-Developed Site Hydrology).
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
�2 Renton,Washingcon
r���
' South Basin
- The South Basin is comprised of the student parking area,multiple sport fields, hard surface tennis courts,and existing
_ building area.The existing storm conveyance system consists of underground storm conveyance pipes ranging form 4
inches to 18 inches in diameter.
The Phase I improvemenu included the southern portion of the fire lane that connecu the northern surface parking
area around the east side of the school to the fire lane on the south side of the school.The addition of the fire lane
will add approximately 0.373 acres(I 6,248 s�of impervious surface which will trigger flow control requiremenu.This
portion of the fire lane will be gated and only used for occasional maintenance and fire access;therefore,water quality
will not be provided.Some portions of the fire lane will be located over existing impervious surface. Paving overlay is
proposed in those areas,existing impervious areas have not been counted as targeted surfaces for flow control
calculations.
During Phase 2 the drainage rystem in the student parking area located in the southwest portion of the site will be
replaced. No new impervious surface associated with the drainage improvemenu are anticipated at this time.Table 6
below shows the final basin cover characteristics in the disturbed portion of the South Basin.
Table 6:South Basin Disturbed Area Conditions
New Area acres Replaced Area(acres)
0.373 (I 6,247 sf of BMP
Im ervious Treatment Re uired 0.1
Pervious 0.56 0
Total Basin 0.93 AC 0
Detention has been provided via underground detention tanks consisting of 60-inch diameter pipes located south of
the school building. French drains and new downspout connections will be also added along the south side of the
building.The detention tanks will be located at a higher elevation relative to some of the added (targeted) impervious
surface.The project proposes to collect and detain existing roof(non-targeted)area of equal or greater area in lieu of
detaining for the portions of added impervious area that is too low to collect via gravity(area swap}.The remaining
portions of the exiting classroom building roof area will bypass the 60-inch detention pipe system.
The roof area has been calculated as forested for the pre-developed condition where it is swapped with the added fire
lane paving. Due to the tributary areas to downspouu it will be necessary to rout a small portion of roof area that
exceeds the rargeted impervious surface threshold.The existing roof area that exceeds the targeted impervious
surface area that is routed through the detention tanks will be modeled as impervious for the pre-developed and post-
developed conditions.The excess area will not exceed 50%of the targeted flows per section I.2.3.2.F;bypass o f runo(f
from non-rargeted surface.
The new impervious surface associated with the fire lane and pervious area that will be altered from the existing
condition will all be modeled as forested for the pre-developed conditions and impervious or till grass as the post- ',
developed condition.Areas that replace impervious surface have not been counted as targeted impervious surface. '�,
Refer to the table 7 below for a summary of the runoff areas utilized for flow control calculations. �!,
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
�3 Renton,Washington
Table 7:South Basin Flow Control Sizin Areas
Area acres
Existin Im ervious Non Tar eted Im rvious 0.I
Existin Pervious Non Tar eted Pervious 0
New Im ervious Surface ar eted Im ervious 0.373
New Pervious Surface ar eted Pervious 0.560
Total Miti ated Im ervious 0.473
Total Miti ated Pervious 0.560
Total Miti ted Area I.03
Performance Standards and Flow Control System(Parts C and D)
The detention systems have been sized to meet all of the requiremenu of the KCSWDM section 5.3.3 (Level II
detention—Stream Protection Standard). The discharge frequency from the proposed detention facilities will be
compared with the total discharge frequency of the (historic)existing basin.The detention systems were sized such
that the discharge flow durations are maintained at or below their pre-existing(forested)levels for storm events
between %z the two-year to the 50-year storm event at the downstream point of compliance.Should the rate of
runoff exceed the capacity of the detention facility beyond the 50-year storm event,stormwater will flow through the
overflow of the facility and continue through underground storm pipes to the existing discharge point
The detention facilities were modeled using MGS Flood Version 4.09. Existing areas area modeled as forested with
the exception of the non-targeted upstream areas,which are modeled as existing conditions. Non-targeted areas
included are existing asphalt pavement that will not be removed and existing roof area that will not be altered as a
result of this project Proposed areas are modeled as their developed conditions.
This project has two new detention systems:
In the North Basin the combined detention/wet vault will provide approximately 25,200 cubic feet of live storage. In the
South Basin the 60-inch diameter detention tank system located at the southeast corner of the exiting classroom
building will provide 9,620 cubic feet of live storage. Refer to the table 8 below for a summary of the flow control
facilities for this project.
Table 8: Summa o Flow Control Focilities Insialled in Phase 1
Storage Summary North Basin Vault South Basin b0-inch Total
Pi System Volume
Re uired Live Stora e 23,100 cubic feet 9,620 cubic feet 32,720
Provided Live Stora e 25,200 cubic feet 9,620 cubic feet 34,820
Storm water BMP's will be applied to approximately 55,450 square feet of targeted and existing impervious surface.
The project will utilize Permeable Pavement and Basic Dispersion BMP's selected from Appendix C of the KCSWDM.
Some target areas are too steep or otherwise infeasible to effectively provide BMP's;the project will therefore use an
equivalent area from existing impervious surfaces around the site to compensate. See Table 9a for a summary of the
BMP's as they are applied to the site and Figure I 2b for a map showing these areas.
As discussed in other por�ions of this report the Phase I construction was completed in 201 I. During Phase I the final
projecc detention systems and stormwater BMP's were installed.Only Phase 2 BMP's will be required for the
additional targeted impervious surface.The table below provides a tabular summary of stormwater features that will
be installed and shows what phase they were or will be completed.
COUGHLINPORTERWNDEEN Lindbergh High School Improvemenu I�,
�4 Renton,Washington �!I
Table 90:Siorm Facilities
Phase
Drainage Feature Constructed Size
25,200(cf) Live
Combined Storage+8,400(cf)
Detention/Wet Vault 1 Dead Storage
60" dia. Detention 9,620 (cf) Live
Tanks 1 Storage
Cartridge Filter Manhole 1 3 Cartridge Filters
BMP#1 1 14,437 (sf)
BMP#2 1 1175 (sf)
BMP#3 1 500(sf)
BMP#4 1 1375 (sf)
BMP#5 1 1730(sf)
BMP#6 1 4200(sf)
BMP#7 1 700(sf)
BMP#8 1 4190(sf)
BMP#9 1 700(sf)
BMP#10 1 500 (sf)
BMP#11 1 700 (sf)
BMP#12 1 500 (s�
BMP#13 1 1600 (sf)
BMP#14 1 1700 (sf)
BMP#15 1 750 (sf)
BMP#16 1 3500{sf)
BMP#17 4500(sf)
BMP#18 2 \ 8100(sf)
BMP#19 2 7600(sf)
BMP#20 2 600 (sf)
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
�5 Renton,Washington
Table 9b:Com leted Phase I BMP Summo Table
Area
BMP# Phase Basin (sf) BMP*
1 1 N 14437 GFTBD
2 1 N 1175 PC
3 1 N 500 PP
4 1 S 1375 PP
5 1 5 1730 PP
6 1 S 4200 SFBD
7 1 S 700 SFBD
8 1 *X 4190 SFBD
9 1 *X 700 SFBD * PC= Porous Concrete
PAC= Porous Asphalt Concrete
GFTBD = Gravel Filled Trenches for Basic
10 1 *X 500 SFBD Dispersion
11 1 *X 700 SFBD
12 1 *X 500 SFBD SFBD=Sheet Flow Basic Dispersion
13 1 *X 1600 SFBD RPBD= Rock Pad Basic Dispersion
14 1 *X 1700 SFBD RG= Rain Garden
15 1 *X 750 SFBD
16 1 N 3500 RPBD * X= Existing Impervious Surface
17 1 5 4500 GFTBD
sf
�= 42,757 (check)
Phase 1 Targeted Impervious Surface=42,252 sf
Phase I BMP's above were installed during the previous phase of construction.
Table 9c:Phase 2 BMP Summa Table '
BMP# Phase Basin Area (sf� BMP*
18 2 N 8100 PAC
19 2 N 7600 PC
20 2 N 600 RG
�= 16,300 sf(check)
Phase 2 Targeted Impervious Surface=13,068 sf
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
�fi Renwn,Washington
Water Quality System(Part E)
Standard Requirements ,
The Lindbergh High School projecc site is located within the Lower Cedar River Drainage Basin,an area designated as
an Enhanced Water Quality Treatment Area by Water Applications Map adopted with the KCSWDM.
Water quality treatment will be provided for all new pollution generating impervious surfaces. All new pollution
generating impervious surfaces are within the North Basin. These areas include the new eastern parking lot(phase I)
and the new central parking lot in phase 2. See table 10 for a summary of the areas requiring treatment
Table 10:Water ual' Treatment Areas
Area s
Phase I New Im ervious Surface 18,500
Phase 2 New Im ervious Surface b ass I 6,I 17
Total Areas Re uirin Treatment 34,617
Re laced PGIS Area sw ed with b ass 23,522
Toral PGIS Treated throu WQ Facili 42,022
Note: This table shows the minimum required areas treated in the water quality facilities. These water quality
rystems have been sized to treat all incoming flow rates. See table 5 for the areas contributing to the water qualiq
systems.
This project will provide water quality in accordance with Enhanced water quality requiremenu of the KCSWDM
(section 6.4.2)as amended by the City of Renton.Water quality treatment will be performed by a combination of
dead storage in a combined detenaon/water quality vault followed by a CSF cartridge filter located in the northern
parking lot. This system is consistent with Table 6.1.2A of the 2009 KCSWDM,"Paired Facilities for Enhanced Basic
Treatment Train,Option 3"(6th row down).
In the North Basin the combined detention/wet vault will provide approximately 8,400 cubic feet of water quality dead
storage. A manhole containing(3)CFS media filter cartridges will provide the second facility in the Enhanced
Treatment Train. See table I I for a summary of the water quality facilities for this project
Table 11: Summa o Water uali S stem installed Durin Phase 1
Facili Re uired Ca aci Facility C acity
Wet Vault 7,553 cubic feet 8,400 cubic feet
CSF Cartrid e Filters 3 total 0.06 cfs 0.08 cfs
The South Basin improvemenu include the southern portion of the fire lane that connecu the northern surface
parking area around the east side of the school to the fire lane on the south side of the scho�l.This portion of the fire
lane will be gated and only used for occasional maintenance and fire access;therefore,water quality will not be
provided.
Spill Control
Spill control is required for projecu constructing or replacing onsite pipe systems that receive runoff from polluaon-
generating surfaces such as parking lou(1.2.4-G). Spill control measures are intended to temporarily detain oil or
other floatable pollutants and prevent them from entering the downstream storm system (4.2.I). Spill control will be '
provided by two control risers located in each of the inlet catch basins directly upstream from the detention vaul�The
control riser will be designed per KCSWDM section 5.3.4.I and will consist of multiple orifice restrictors constructed
on a tee section per Figure 5.3.4.A ,
Flow Control and Discharge Requirements 'I
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu I
17 Renton,Washingcon
The proposed development adds or replaces over 2,000 square feet of impervious surface;therefore,flow control
facilities must be provided per KCSWDM 5.2.1.3 as described in Part B above.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
�8 Renton,Washington
Figure 10 - Existing Site Hydrology
North Basin �
Downstream
=a:s; •g _.., " - -
S stem Classroom �' ; �:
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COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
Figure I I - Developed Site Hydrology
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COUGHLINPORTERLUNDEEN Lindbergh High School Improvements ,
Renton,�'�'ashington '
Figure I I a — Area Swap Exhibit
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COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
Figure I 2 - Flow Control Applications Map
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COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
Figure I 3 – Water Quality Applications Map
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COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
North Basin Vault Calculations
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,�ti ashington
MGS FLOOD I
PROJECT REPORT I
Program Version: MGSFIood 4.11 �
Program License Number: 200610002
Run Date: 06121/2011 12:47 PM �
In ut File Name: No�th Basin Resubmittal.fld
P
Project Name: Lindbergh High School Improvements
Analysis Title: North Basin
Comments: ,
PRECIPITATION INPUT �
Com utational Time Ste Minutes : 60
P P ( ) I
Extended Precipitation Timeseries Selected ��
Climatic Region Number: 13
Full Period of Record Available used for Routing '
Precipitation Station : 96004005 Puget East 40 in 5min 10/0111939-10/01l2097 ,
Evaporation Station : 961040 Puget East 40 in MAP '
I Evaporation Scale Factor : 0.750
HSPF Parameter Region Number 1
HSPF Parameter Region Name USGS Default
•�������w* Default HSPF Parameters Used (Not Modified by User) ""�•�""'""
R��A***N#*#»���4*�*�*WATERSHED DEFINITION ���Af11klARf#ik�f�#A��#•
---------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Phase 1 ---------
------Area(Acres) -------
Till Forest 2.797
Till Pasture 0.000
Till Grass 0.313
Oulwash Forest O.Q00
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0 000
Green Roof 0.000
User 0.000
Impervious 0250
Subbasin Total 3.360
Link Name: Combination Detention Wet Vault
Link Type: Structure
Downstream Link Name: Downstream POC
Prismatic Pond Option Used
Pond Floor Elevation (ft) : 100.00
Riser Crest Elevation (ft) : 106.00
Max Pond Elevation (ft) : 106.50
Storage Depth (ft) : 6.00
Pond Bottom Length (ft) : 110.0
Pond Bottom Width(ft) : 35.0
Pond Side Slopes(ft/ft) : L1=0.00 L2= 0.00 W1= 0.00 W2= 0.00
Bottom Area (sq-ft) : 3850.
Area at Riser Crest EI (sq-ft) : 3,850.
(acres) : 0.088
Volume at Riser Crest(cu-ft) : 23,100.
(ac-ft) : 0.530
Area at Max Elevation (sq-ft) : 3850.
(acres) : 0.088
Vol at Max Elevation (cu-ft) : 25,410.
(ac-ft) : 0.583
Massmann Infiltration Option Used '
Hydraulic Conductivity(inlhr) : 0.00
Depth to Water Table(ft) : 100.00 I
Bio-Fouling Potential : Low
Maintenance Average or Better
Riser Geometry
Riser Structure Type Circular
Riser Diameter(in) : 12.00
Common Length (ft) : 0.040
Riser Crest Elevation : 106.00 ft
Hydraulic Structure Geometry
Number of Devices: 2
---Device Number 1 ---
Device Type : Circular Orifice
Cont�ol Elevation (ft) : 100.00
Diameter(in) : 1 10
Orientation � Horizontal
Elbow No
---Device Number 2 ---
Device Type Circular Orifice
Control Elevation (ft) 104.00
Diameter(in) : 1.20
Orientation . Horizontal
Elbow Yes
""'"•*"*""•""+"•FLOOD FREQUENCY AND DURATION STATISTICS`"'""""'**"""
------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 1
""""'" Subbasin: Phase 1 !tR}1ff�ff
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringarten Plotting Position)
Tr(yrs) Flood Peak (cfs)
2-Year 0.122
5-Year 0.200
10-Year 0.245
25-Year 0.326
50-Year 0.361
100-Year 0.436
200-Year 0.572
•'�'•""` Link: Downstream POC ""`""""' Link Inflow Frequency
Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position}
Tr (yrs) Flood Peak (cfs)
--------------------------------------
--------------------------------------
2-Year 0.122
5-Year 0.200
10-Year 0.245
25-Year 0.326
50-Year 0.361
100-Year 0.436
200-Year 0.572
---------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 2
Number of Links: 4
'•"'"'•'" Subbasin: Targeted """""
Flood Frequency Data(cfs)
, (Recurrence Interval Computed Using Gringorten Plottmg Position)
Tr (yrs) Flood Peak(cfs)
--------------------------------------
--------------------------------------
2-Year 0.314
5-Year 0.430
10-Year 0 547
25-Year 0.743
50-Year 0.856
100-Year 0.905
200-Year 1.146
R'�w�*f'R* Subbasin: Non-targeted +��A#�t�frR�
Flood Frequency Data(cfs)
(Recurrence interoal Computed Using Gringorten Plotting Position)
Tr(yrs) Flood Peak(cfs)
--------------------------------------
--------------------------------------
2-Year 0.067
5-Year 0.113
10-Year 0.136
25-Year 0.178
50-Year 0.200
100-Year 0.207
200-Year 0.256
r•�w+asra• Link: Combination Detention Wet Vault """"" Link Inflow
Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr(yrs) Flood Peak (cfs)
--------------------------------------
2-Year 0.400
5-Year 0.546
10-Year 0.679
25-Year 0.914
50-Year 1.061
100-Year 1.104
200-Year 1.399
"'"""" Link: Combination Detentfon Wet Vault """"" Link Outflow 1
Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
--------------------------------------
2-Year 0.055
5-Year 0.075
10-Year 0.108
25-Year 0.145
50-Year 0.238
100-Year 0.332
200-Year 0 455
"""*""'"" Link: Combination Detention Wet Vault `"'""""' Link WSEL Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr(yrs) WSEL Peak (ft)
--------------------------------------
--------------------------------------
1.05-Year 101.428
1.11-Year 101.563
1.25-Year 101.967
2.00-Year 102.861
3.33-Year 103.460
5-Year 104.069
10-Year 104.943
25-Year 105.649 �
50-Year 106.046
100-Year 106.070
",'••"'• Link: Downstream POC """"" Link Inflow Frequency
Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position) �
Tr(yrs) Flood Peak (cfs)
--------------------------------------
2-Year 0.055
5-Year 0.075
10-Year 0.108
25-Year 0.145
50-Year 0.238
100-Year 0.332
200-Year 0.455
•�y�w�+r*• Link: Targeted Link """'"" Link Inflow Frequency
Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
--------------------------------------
2-Year 0.314
5-Year 0.430
10-Year 0.547
25-Year 0.743
50-Year 0.856
100-Year 0.905
200-Year 1.146
"""`"" Link: Targeted Link """"" Link Outflow 1 Frequency
Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Piotting Position)
Tr(yrs) Flood Peak (cfs)
--------------------------------------
--------------------------------------
2-Year 0.314
5-Year 0.430
10-Year 0.547
25-Year 0.743
50-Year 0.856
100-Year 0 905
200-Year 1 146
'"""'*"' Link: Non-targeted Link """"" Link Inflow Frequency
Stats
Flood Frequency Data(cfs}
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr(yrs) Ftood Peak (cfs)
--------------------------------------
--------------------------------------
2-Year 0.087
5-Year 0.113
10-Year 0.136
25-Year 0.17�
50-Year 0.200
100-Year 0 20�
200-Year 0 2��
""""" Link. Non-targeted Link """"" Link Outflow 1 Frequency
Stats
Flood Frequency Data(cfs}
(Recurrence Interval Computed Using Gringorten Plotting Positlon)
Tr (yrs� Flood Peak (cfs)
--------------------------------------
--------------------------------------
2-Year 0.087
5-Year 0.113
10-Year 0.136
25-Year 0.178
50-Year 0.200
100-Year 0.207
200-Year 0.256
„*"'*"'**'Water Quality Facility Data ��*��+Rk�t��4f
f����+�►w� Link: Combination Oetention Wet Vault """”"
Basic Wet Pond Volume (91% Exceedance): 7553. cu-ft
Computed Large Wet Pond Volume, 1.5"Basic Volume: 11329. cu-ft
•""•*"•*'Compliance Point Results •••"•",'•'•
�
Scenario Predeveloped Compliance Link: Downstream POC
Scenario Postdeveloped Compliance Link: Downstream POC
"" 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 0.122 2-Year 0.055
5-Year 0.200 5-Year 0.075
10-Year 0.245 10-Year 0.108
25-Year 0.326 25-Year 0.145
50-Year 0.361 50-Year 0.238
100-Year 0.436 100-Year 0.332
200-Year 0.572 200-Year 0.455 i
" Record too Short to Compute Peak Discharge for These Recurrence Interoals
"•' Flow Duration Performance According to Dept. of Ecology Criteria ""
Excursion at Predeveloped '/2�2 (Must be Less Than 0%): �1.5% PASS
Maximum Excursion from YzQ2 to Q2 (Must be Less Than 0%): -37.4% PASS
Maximum Excursion from �2 to Q50(Must be less than 10°/a): -44.4% PASS
Percent Excursion from Q2 to�50 (Must be less than 50%): 0.0% PASS
POND MEETS ALL DURATION DESIGN CRITERIA: PASS
;
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A���%uTCAU�� Determining Number of
i�i►�:� i `i�
STORMWATER Cartridges for Systems
so�uTioNs�N�. Downstream of Detention
CONTECH Stormwater Solutions Inc. Engineer JHR
Date 6l16/2011
Site fnformation
Project Name Lindbergh High School Site Improvements
Project State Washington I
Project Location Renton
Drainage Area, Ad 3.36 ac
Impervious Area, Ai 0.98 ac
Pervious Area,Ap 2.38
% Impervious 29%
Runoff Coefficient, Rc 0.31
Upstream Detention System
Peak release rate from detention, Q�t,�SC�e, 0.33 cfs
Treatment release rate from detention, C1,�as�,rea, 0.06 cfs
Detention pretreatment credit 50%
from removal efficienc calcs
( Y ) �1--
Mass loading calculations
Mean Annual Rainfalt, P 36 in
Agency required % removal 80%
Percent Runoff Capture 90%
Mean Annual Runoff,V, 123,493 n�
Event Mean Concentration of Pollutant, EMC 60 mg/l
Annual Mass Load, M,o,a, 462.28 Ibs
Filter System
Filtration brand StormFilter
Cartridge height 27 in
Specific Flow Rate 1.0 gpmlft2
Number of cartridges-mass loading
Mass removed by pretreatment system. M� 231.14 Ibs
Mass load to�Iters after pretreatment. Mpasst 231.14 Ibs
Estimate the required filter efficiency, E�,�� 0.6�
Mass to be captured by filters, M�,�� 138.69 Ibs
Allowabie Cartridge Flow rate, Q�,, 11.25
Mass load per cartridge. M�„(Ibs) 54.00 Ibs
Number of Cartridges required, Nmass 3
Treatment Capaciry 0.08 cfs
Determine Critical Sizing Value
Number of Cartridges using Q��asatreal� Nnew 3
Methad to Use: MASS-LOADING
SUMMARY
Treatment Flow Rate, cfs 0.08
Cartridge Flow Rate, gpm 11.3
Number of Cartridges 3
1 of 1
South Basin Tank Calculations
COUGHUNPORTERLUNDEEN Lindbergh High School Improvement�
Renton,lNashington
MGS FLOOD
PROJECT REPORT
Prog�am Version: MGSFIood 4.11
Program License Number: 200610002
Run Date: 0412712011 4:13 PM
Input File Name: Soulh Basin 100%.fld
Project Name: Lindbergh HS
Analysis Tille: Soulh Basin Detention Tanks
Comments:
PRECIPITATION INPUT
Computational Time Step (Minutes) 6G
Extended Precipilation Timeseries :
Climatic Region Number: 13
Full Period of Record Available usea tor ko�;� :
Precipitation Station � 96004005 Puoe �_: �C �� � _ . _ _
Evaporation Station 961040 Pugei Eas� 40 �n MAF
Evaporation Scale Factor : 0.750
HSPF Parameter Region Number: 1
HSPF Parameter Region Name � USGS Default
""""" Defautl HSPF Paramelers Used Nol Modified b Use� """
� Y � ...,....
"""""""""""'WATERSHED bEFINITION ��k�••�M����i+•rw�.s.•
--------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin Predeveloped ----------
-------Area(Acres) --------
Till Forest 0 933
Till Pasture 0.000
Till Grass 0.000
Outwash Foresi 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
tiNetland 0.000
Green Roof 0.000
User 0.000
Impervious 0 100
Subbasin Total 1.033
_�_________.______SCENARIO: POSTDEVELOPED
Number ot Subbasins 2
---------- Subbasin : Targeted Surface ----------
------Area(Acres) --------
Till Forest 0.000
Till Pasture 0.000
Till Grass 0.560
Outwash Foresl 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Rooi 0.000
User 0.000
Impervious 0.373
Subbasin Tolal 0.933
---------- Subbasin Non-Targeted ----------
-------Area(Acres) --------
Tiil Forest 0.00(�
Till Pasture 0.0
Till Grass O G
Outwash Forest 0.0�
Outwash Pasture O.OGi�
Outwash Grass 0.000
Wetland Q 000
Green Root 0.000
User 0.000
Impervious 0.100
Subbasin Total 0.100
................�....,,,. LINK DATA...,...,..,.,..,....,,.....,..,
----------------------SCENARIO: PREDEVELOPED
Number of Links: 1
Link Name: Predeveloped
Link Type: Copy
Downstream Link: None
.........,...,,,,.,....., LINK DATA...............................
----------------------SCENARIO POSTDEVELOPEO
Number of Links: 3
Link Name: Detention
Link Type: Slructure- Pipes
Downstream Link: None
User Specified Elevation Volume Table Used
Elevation (ft) Pond Volume (cu-ft)
100.00 0.
100.10 0.
100.20 0.
100.30 0.
100.40 0.
100.50 0. Sediment Storaqe
100.60 139.
100.70 288.
100.80 446.
100.90 614.
101.00 789.
101.10 971.
101.20 1160.
101.30 1355.
101.40 1555.
101.50 1761.
101.60 1971.
101.70 2185.
101.80 2404.
101.90 2625.
102.00 2850.
102.10 3078.
102.20 3308.
102.30 3540.
102.40 3774.
102.50 4010.
102.60 4248.
102.70 4486.
102.80 4725.
102.90 4965.
103.00 5205.
103.10 5445.
103.20 5684.
103.30 5924.
103.40 6162.
103.50 6399.
103.60 6635.
103.70 6869.
103.80 7102.
103.90 7332.
104.00 7560.
104,10 7784.
104.20 8006.
104.30 8224
104.40 8438
104.50 8649.
104.60 8854.
104.70 9054.
104 80 9249.
104.90 9438.
105.00 9621. Toa of Pipe
Massmann Infiltration Oplion Used
Hydraulic Conductivity(in/hr) : 0.00
Depth to Water Table(it) : 100.00
Bio-Fouling Potential Low
Maintenance Average or Better
Riser Geometry
Riser Structure Type Circular i
Riser Diameter (in) 12.00
Common Lenglh(it) : 0.030
Riser Crest Elevation 104.50 ff
Hydraulic Structure Geometry
Number of Devices 2
--Device Number 1 ---
Device Type : Circular Orifice
Control Eleval�on (ft) : 100 00
Diameter(in) : 0.65
Orientation � Horizontal
Elbow No
---Device Number 2 --- I
Device Type : Circular Onfice
Control Eleval�on (ft) 103.00
Diameter(in} 0.75
Orientation : Hori2ontal
Elbow : Yes
Link Name: Targeted
Link Type� Copy
Downslream Link Name: �etention
Link Name: Non-targeted
Link Type Copy
Downstream Link Name: Detention
"""""""""""'FLOOD FREQUENCY AND DURATIUN STATISTICS'""""'"""""'
---------------------SCENARIO: PREDEVELOPED
Number oi Subbasins 1
Number of Links 1
---------------------SCENARIO: POSTDEVELOPED
Number oi Subbasins. 2
Number of Lmks: 3
""""" Link: Detention """"" Link WSEL
Stats
WSEL Frequency Data(fi}
(Recurrence Inlerva! Computed Using Gringorten Plotting Posit�on)
Tr(yrs) WSEL Peak (ft)
--------------------------------------
--------------------------------------
1.05-Year 101468
1.11-Year 101.654
1.25-Yea� 101.849
2.00-Year 102.372
3.33-Year 102.778
5-Year 103.071
10-Year 103.642
25-Year 104.193
50-Yea� 104.514
100-Year 104.525
"•"•""'Water Quality Facility Data*fRf*R11�f11r+
-------------------SCENARIO PREDEVEIOPED
Infillralion/Filtralion StaliStic�
Total Runofi Volume(ac-fi). 128.OQ
Total Runoff Infiltrated (ac-fl): 0.00. 0.00°i�
Total Runoff Fillered (ac-it): 0.00, 0.00%
Percent Treated (Infillrated+Fillered)1Total Volume. 0.00°io
--------------------SCENARIO POSTDEVELOPED
Number oi Links 3
""""" Link Detenlion """""
Basic Wet Pond Volume (91% Exceedance) 2753 cu-ft
Compuled Large Wet Pond Volume. 1.5'Basic Volume: 4129 cu-ft
Infiltralion/Fil►ration Statistics-------------------
Total Runoff Volume (ac-ftj 320 87
Total Runofi Intiltrated (ac-fl): 0.00, 0.00°i�
Total Runoff Filtered (ac-ft) 0 00. 0 00%
Percent Treated (Infillrated+Filtered)lToial Volume 0 00°/0
"""""'Compliance Point Results """"""'
Scenario Predeveloped Compliance Link: Predeveloped
Scenario Postdeveloped Compliance Link: Detention
"" Point of Compliance Flow Frequency Data"'
Recurrence Interval Computed Using Gringo�ten Plotting Position
Predevelopmenl Runoff Postdevelopmenl RunoH
Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs)
2-Year 0.039 2-Year 0.017
5-Year 0.061 5-Year 0.024
10-Year 0.073 10-Year 0.033
25-Year 0.092 25-Year 0.039
50-Year 0.105 50-Year 0.068
100-Year 0.125 100-Year 0.085
200-Year 0.164 200-Year 0.173
" Record ioo Short to Compute Peak Discharge for These Recurrence Intervals
"" Flow Duration Performance According to Dept. of Ecology Criteria"'"
Excursion at Predeveloped Yz�2 (Must be Less Than 0%): -57.8% PASS
Maximum Excursion from YzQ2 to Q2(Musl be Less Than 0%) -41.5% PASS
Maximum Excursion from �2 lo Q50(Must be less than 10%) -66 5`/o PASS
Percenl Excursion from �2 to 050(Must be less than 50%): 0.0% PASS
POND MEETS ALL DURATION DESIGN CRITERIA: PASS
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BMP Calculations
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
COVGHLINPORTERLUNDEEN
A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION
Lindber�h Hi�h School
BMP CALCULATIONS AND SUMMARY
BMP 1 Per 2009 KCSWDM Section C.2.4.4
14,437/3500=4.12 Sections of 50'Dispersal Trench
4.12 x 50 LF=206 LF Dispersal Trench Resquired
215 Lf Provided
BMP 2 Installation will be completed per 2009 KCSWDM Section C.2.6.2
BMP 3 Installation will be completed per 2009 KCSWDM Section C.2.6.3
BMP 4 Installation will be completed per 2009 KCSWDM Section C.2.6.3
BMP 5 Installation wil)be completed per 2009 KCSWDM Section C.2.6.3
BMP 6 Installation will be completed per 2009 KCSWDM Section C.2.4.5
BMP 7 Installation will be completed per 2009 KCSWDM Section C.2.4.5
BMP 8 Installation will be completed per 2009 KCSWDM Section C.2.4.5
BMP 9 Installation will be completed per 2009 KCSWDM Section C.2.4.5
BMP 10 Installation will be completed per 2009 KCSWDM Section C.2.4.5
BMP 11 Installation will be completed per 2009 KCSWDM Section C.2.4.5
BMP 12 Installation will be completed per 2009 KCSWDM Section C.2.4.5
BMP 13 Installation will be completed per 2009 KCSWDM Section C.2.4.5
BMP 14 Installation will be completed per 2009 KCSWDM Sedion C.2.4.5
BMP 15 Installation will be completed per 2009 KCSWDM Sedion C.2.4.5
BMP 16 Installation will be completed per 2009 KCSWDM Sedion C.2.4.3
BMP 17 Per 2009 KCSWDM Section C.2.4.4
5000/3500=1.4 Sections of 50'Dispersal Trench
1.4 x 50 LF=70 LF Dispersal Trench Resquired
70 LF Provided
BMP 18 Installation will be completed per 2009 KCSWDM Section C.2.6.3
BMP 19 Installation will be completed per 2009 KCSWDM Section C.2.6.2
BMP 20 Per 2009 KCSWDM Section C.2.5.2
Runoff Source—600 squaze feet(driveway)
:�finimum Storage Required=1 foot depth
Storage Volume Needed=600 square feet x 0.25 =150 cubic feet
Volume Provided—151 squaze feet(check)
Project:Lindbergh High School Designed By:JCF Date 5/17;12
Project No. Client:Rencon School District Checked By: KNK
413 Pine Street Suite 300 Seatt�e,WA 98101 P:206/343-0460 F:206i343-5691
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
This section discusses the criteria that will be used to analyze and design the proposed storm conveyance system.
Conveyance calculations will be provided with the full drainage submitul.
Standard Requirements(based on KCSWDM and SAO):
1. Focilities must convey the 100-year flow without overtopping the crown of the roadway, flooding
buildings, and i f sheet flow occun it must pass through a drainage easement The detention facilities are
designed to convey the 100-year developed flow.
2. New pi�pe systems and culverts must convey the 25-year flow with ai least 0.5 feei o f freeboard. (1.2.4-1).
The new pipe systems are designed to convey the 25-year flow with at least 0.5 feet of freeboard.
3. Bridges must convey the 100-year flow and provide a minimum of two fee�varying u�p to six fee� o f
clearonce based on 25%of the mean channel width. (1.2.4-2)(4.3.5-6). N/A This project does not propose a
bridge.
4. Drainage ditches must convey the 25-year flow with 0.5 feet of freeboord and the 100.year flow without
overtopping. (1.2.4-2). Drainage ditches are not proposed as part of this proposed development
5. Floodplain Crossings must not increase the base flood elevation by more than 0.01 feet[41(83.C)]ond
shall not reduce the flood storoge volume[37(82.A)]. Piers shall not be constructed in the FEMA
floodway. [41(83.F.1)]. There are no floodplain crossings associated with the construction of this project.
6. Streom Crossings shall require o 6ridge for class 1 streams that does not disturb or bonks. For type 2 and
type 3 steams, open bottom cufverts or other method may be used that will not harm the stream or
inhibit fish passage. (60(95.B)]. There are no stream crossings associated with the construction of this project.
7. Discharge at natural location is required and must produce no signi ficant impacts to the downstream
property(1.2.1-I). The project will discharge to the existing discharge locations located in the northwest corner
and the southeast corner of the site. '
Detailed information and calculations are contained at the end of this section. I
On-site Conveyance
Existing Conditions: �
Storm water discharges from the property at two locations: the northwest and southeast corners of the property.
Existing storm conveyance lines varying in size from 4-inch to I 8-inch diameter exist onsite.There are no existing I
detention facilities.
Developed Storm system description:
The on-site conveyance system will consist of Type I and Type 2 catch basins,8 and I 2-inch conveyance lines,water
quality facilities,and detention facilities.
Outfalls
The project will connect to existing storm drainage pipes.There will be no outfall systems in this project
COUGHLINPORTERLUNDEEN Lindbergh High$chool Improvemenu
�9 Renton,Washington
North Basin Conveyance Calculations
Conveyance calculations were performed using a conservative simplified method.The entire tributary area
for each conveyance line was summed up.The flows generated from the total tributary azea are added to the I,
most upstream point in the conveyance system. j
Pervious Total �I
Sub- Impervious Area Area QZS_Y� '
Basin Area (ac) (ac) {ac) (cfs)
Area 1 0.26 1.44 1.70 0.680
Area 2 1.32 0.52 1.84 1.130
Area 3 0.29 0.01 0.30 0.203
Area 4 0.04 0.01 0.05 0.032 I
Area 5 0.97 2.14 3.11 1.358
*See next page showing areas
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,Washington
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MGS FLOOD
PROJECT REPORT
Program Version: MGSFIood 4.12
Program License Number: 200610002
Run Date: 05116l2012 1:33 PM
Input File Name: Area 1.fld
Project Name: Lindbergh High School Improvements
Analysis Title: Phase 2 Conveyance
Comments:
PRECIPITATION INPUT
Computational Time Step(Minutes): 15
Extended Precipitation Timeseries Selected
Climatic Region Number: 13
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 ***********************
---------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
--------- Subbasin : Area 1 ----------
-------Area(Acresj
' Till Forest 1.700
Till Pasture 0.000
Till Grass 0.000
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 0.000
Subbasin Total 1.700
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Area 1 ----------
-------Area(Acres) --------
Till Forest 0.000
Till Pasture 0.000
Till Grass 1.440
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 0.260
----------------------------------------------
Subbasin Total 1.700
*«******:****�,,********** LINK DATA*****************,�.***�,.**�***
---------------------SCENARIO: PREDEVELOPED
Number of Links: 0
**********,��*********** LINK DATA*******��***�**�*************�
---------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
***"**"***************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins '
�!��r-il-,c- nfl �nlrc� �
.. .... . .. .�e��uii:i w,Zuafiiy i ui..iiit�+ vci�ci � ���.: .. ...
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
il
II ' I
I
*****'`*"*'"`Compliance Point Results****'`********
� Scenario Predeveloped Compliance Subbasin: Area 1
Scenario Postdeveloped Compliance Subbasin: Area 1
; *** 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 0.036 2-Year 0.232
5-Year 0.059 5-Year 0.339
10-Year 0.080 10-Year 0.479
25-Year 0.101 25-Year 0.680
50-Year 0.129 50-Year 0.861
100-Year 0.139 100-Year 0.984
200-Year 0.217 200-Year 1.066
*'` Record too Short to Compute Peak Discharge for These Recurrence Intervals
MGS FLOOD
PROJECT REPORT
Program Version: MGSFIood 4.12
Program License Number: 200610002
Run Date: 05/1612012 1:26 PM
Input File Name: Area 2.fld
Project Name: Lindbergh High School Improvements
Analysis Title: Phase 2 Conveyance
Comments:
PRECIPITATION INPUT
Computational Time Step (Minutes): 15
Extended Precipitation Timeseries Selected
Climatic Region Number: 13
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) **rr*xx*r**r**x
**********************WATERSHED DEFINITION ***"***"`**'`**'`***'""'`"'
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
--------- Subbasin : Area 2 ---------
-------Area(Acres)--------
Till Forest 1.840
Till Pasture 0.000
Till Grass 0.000
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 0.000
Subbasin Total 1.840
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
--------- Subbasin : Area 2 ----------
-------Area(Acres)--------
Till Forest 0.000
Till Pasture 0.000
Till Grass 0.520
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 1.320
--------------------------------------------
Subbasin Total 1.840
****�**************:*:*** LINK DATA*********�*********************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
*w***************�***�**� LIN K DATA*****.,***********************:*
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
******************'`*'`*FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
---------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
Number af Links: 0
*****'`*****Water Quality Facility Data*************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
******'`***"Compliance Point Results*'`'"""`*"**"'`*
Scenario Predeveloped Compliance Subbasin: Area 2
Scenario Postdeveloped Compliance Subbasin: Area 2
*** 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 0.039 2-Year 0.537
5-Year 0.064 5-Yea� 0.684
10-Year 0.086 10-Year 0.831
25-Year 0.109 25-Year 1.130
50-Year 0.139 50-Year 1.307
100-Year 0.151 100-Year 1.634
200-Year 0.235 200-Year 1.653
*'` Record too Short to Compute Peak Discharge for These Recurrence Intervals
MGS FLOOD
PROJECT REPORT
Program Version: MGSFIood 4.12
Program License Number: 200610002
Run Date: 05/16/2012 1:28 PM
Input File Name: Area 3.fld
Project Name: Lindbergh High School Improvements
Analysis Title: Phase 2 Conveyance
Comments:
PRECIPITATION INPUT
Computational Time Step (Minutes): 15
Extended Precipitation Timeseries Selected
Climatic Region Number: 13
Full Period of Record Available used for Routing
Precipitation Station : 96004005 Puget East 40 in 5min 10/01/1939-10/01/2097
Evaporation Stati�n : 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 *************'`***'`*****
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Area 3----------
------Area(Acres)--------
Till Forest 0.300
Till Pasture 0.000
Till Grass 0.000
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
I mpervious 0.000
--------------------------------------------
Subbasin Total 0.300
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Area 3 ----------
-------Area(Acres)-------
Till Forest 0.000
Till Pasture 0.000
Till Grass 0.010
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 0.290
Subbasin Total 0.300
****�***************#*�*� LIN K DATA********�*****�.*w***#**********
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
**********************�** LIN K DATA*******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 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: 0
*`**`******Water Quality Facility Data *****"*"*****
---------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
I
""`*******"Compliance Point Results*""'***"**"*'
Scenario Predeveloped Compliance Subbasin:Area 3
� Scenario Postdeveloped Compliance Subbasin: Area 3
'`''* 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 6.393E-03 2-Year 0.109
5-Yea r 0.010 5-Yea r 0.141
10-Year 0.014 10-Year 0.161
25-Year 0.018 25-Year 0.203
50-Year 0.023 50-Year 0.255
100-Year 0.025 100-Year 0.298
200-Year 0.038 200-Year 0.308
*'' Record too Short to Compute Peak Discharge for These Recurrence Intervals
MGS FLOOD
PROJECT REPORT
Program Version: MGSFIood 4.12
Program License Number: 200610002
Run Date: 05N6/2012 1:30 PM
Input File Name: Area 4.fld
Project Name: Lindbergh High School Improvements
Analysis Title: Phase 2 Conveyance
Comments:
PRECIPITATION INPUT
Computational Time Step(Minutes): 15
Extended Precipitation Timeseries Selected
Climatic Region Number: 13
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 ***'`**'`'"***Y'"'`******'�** '
---------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1 ��
---------- Subbasin : Area 4 ----------
------Area(Acres) --------
Till Forest 0.050
Till Pasture 0.000
Till Grass 0.000
I Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 0.000
' ----------------------------------------------
Subbasin Total 0.050
_____.___________.__SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
--------- Subbasin : Area 4 ----------
-------Area(Acres)--------
Till Forest 0.000
Till Pasture 0.000
Till Grass 0.010
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 0.040
Subbasin Total 0.050
*****,�,F*****,�**�*****,k,t. LINK DATA*#***�,.*****,k.�,�-k,+,k,�*,k+�,k,�**�*
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
**«�**.*****:*********** LINK DATA******.************,�**********
-------------------SCENARIO: POSTDEVELOPED
Number of Links: 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: 0 I
''*****'`***'Water Quality Facility Data'"'''*'`*****"''`
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
**'`***"****Compliance Point Results***'`'`**"'""'**
Scenario Predeveloped Compliance Subbasin: Area 4
Scenario Postdeveloped Compliance Subbasin: Area 4
''** 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 1.065E-03 2-Year 0.016
5-Year 1.737E-03 5-Year 0.020
10-Year 2.340E-03 10-Year 0.024
25-Year 2.967E-03 25-Year 0.032
50-Year 3.786E-03 50-Year 0.037
100-Year 4.103E-03 100-Year 0.046
200-Year 6.386E-03 200-Year 0.047
"* Record too Short to Compute Peak Discharge for These Recurrence Intervals
MGS FLOOD
PROJECT REPORT
Program Version: MGSFIood 4.12
Program License Number: 200610002
Run Date: 05/16/2012 1:31 PM
Input File Name: Area 5.fld
Project Name: Lindbergh High School Improvements
Analysis Title: Phase 2 Conveyance
Comments:
PRECIPITATION INPUT
Computational Time Step (Minutes): 15
Extended Precipitation Timeseries Selected
Climatic Region Number: 13
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 *****'`"'`***'`a"`*"****'`'`"
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
--------- Subbasin : Area 5----------
------Area(Acres)------
Till Forest 3.110
Till Pasture 0.000
Till Grass 0.000
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 0.000 ,
------------------------------------------
Subbasin Total 3.110 I
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Area 5----------
-------Area(Acres)-------
Till Forest 0.000
Till Pasture 0.000
Till Grass 2.140
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 0.970
----------------------------------------------
Subbasin Total 3.110
********«**************** LINK DATA**************�*.************:*
__________________SCENARIO: PREDEVELOPED
Number of Links: 0
**#****�**********�****** LINK DATA***,�,�***,�***********,k,k*,+**�**
----------------------SCENARlO: POSTDEVELOPED
Number of Links: 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: 0
*`***'`''*'`**Water Quality Facility Data*'"`***'`*"*'`**
----------------------SCENARIO: PREDEVELOPED '
Number of Links: 0 I
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
*"'''''"""***Compliance Point Results'`*"`**"**''***
Scenario Predeveloped Compliance Subbasin: Area 5
Scenario Postdeveloped Compliance Subbasin: Area 5
'`*' 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 0.066 2-Year 0.555
5-Year 0.108 5-Year 0.753
10-Year 0.146 10-Year 1.014
25-Year 0.185 25-Year 1.358
50-Year 0.235 50-Year 1.786
100-Year 0.255 100-Year 2.078
200-Year 0.397 200-Year 2.183
*' Record too Short to Compute Peak Discharge for These Recurrence Intervals
�pL P�ga,
Line Inlet Line DnStm Flow Line Line Line Line n-val Invert ]epi11 HGL Vel Vel EGL HGL Invert 7�epth HGL
No. ID ID Ln No Rate _ongth Size 31opo Type Pipe Dn Dn Dn Dn Hd Dn Dn Jmp Dn Up Up Up
(�fs) (ft1 (�n1 (x1 (n) (ft) (ft) 1�a1 ln) ln) lft) lnl (ft) (n)
1 Ex CB#3 Ex SD#3 to Ex SD AR2 Outfall 3.55 76 12 0.50 Cir 0.012 386.27 0.80 387.07 5.27 0.43 387.50 .... 386.65 1.00 387.84
2 =x CB#3A =x 5D#3A ia Ex SD#3 1 3.40 22 12 0.49 Cir 0.012 386.65 1.00 388.16 4.33 029 388.45 .... 386.76 1.00 388.33
3 Sd#34� 5D t13�3 to Ex SD 7�3A 2 3.40 76 12 0.55 Cir 0.012 386.76 1.00 388.55 4.33 0.29 388.85 .... 387.18 1.00 389.15
4 5b�13f3a 56#3D to SD�3�A 3 3.40 134 12 0.50 Cir 0.012 387.18 1.00 389.22 4.33 0.29 389.51 ... 387.85 1.00 390.26
5 sd#48 SD#4B to SD ti3flA 4 1.36 91 12 0.55 Cir 0.012 387.85 1.00 390.51 1.73 0.05 390.56 .... 388.35 1.00 390.63
6 5b#4a 5b#4Q ta Sb#4A 5 1.36 59 12 6.73 Cir 0.012 388.35 1.00 390.64 1.73 0.05 390.68 390.55 392.34 0.49" 392.93 j
7 �D�t5D 5��t5D to Sd#4fl 6 1.36 81 12 1.00 Cir 0.012 392.34 0.49 392.83 3.51 0.19 393.03 ... 393.15 0.49" 393.64
8 SD#51 5b#51 to Sb#50 7 1.36 41 12 1.01 Cir 0.012 393.15 0.49 393.64 3.51 0.19 393.84 .... 393.56 0.49** 394.05
9 5D iR52 5D l�52 to SD#51 8 1.36 78 12 16.65 Cir 0.012 393.56 0.49 394.05 3.51 0.19 394.25 ... 406.50 0.49" 406.99
10 S6#�lb S6#4D to S6�i34A 4 1.37 92 12 2.38 Cir 0.012 387.85 1.00 390.51 1.74 0.05 390.56 .... 390.05 0.58 390.63
11 SD#41 SD#41 to SD#40 10 1.37 91 12 0.50 Cir 0.012 390.05 0.64 390.69 2.58 0.10 390.79 .... 390.51 0.50" 391.01
12 36#4� 5b#42 to Sb#41 11 1.37 59 12 0.49 Cir 0.012 390.51 0.50 391.01 3.52 0.19 391.20 .... 390.80 0.51 391.31
13 5D#43 SD#43 to SD#42 12 1.13 95 12 2.88 Cir 0.012 390.80 0.69 391.49 1.96 0.06 391.55 391.52 393.54 0.45" 393.99 j
14 �6#d4 56#d4 to Sb#4� 72 0.24 68 8 1.00 Cir 0.012 391.10 0.39 391.49 1.11 0.02 391.51 391.48 391.78 0.23" 392.d1 j
15 �D�t45 SD#+15 to SD#44 14 0.20 62 8 3.95 Cir 0.012 391.78 0.23 392.01 1.92 0.06 392.07 392.24 394.22 0.21"* 394.43 j
16 �6#46 5D#46 to Sb#44 14 0.03 20 8 10.08 Cir 0.012 391.78 0.23 392.01 0.30 0.00 392.01 392.07 393.80 0.08`" 393.Q8 j
17 Ex CB#3b =x 5p#36 io Ex Sa#3 1 0.15 88 12 2.73 Cir 0.012 386.65 1.00 388.16 0.18 0.00 388.16 388.15 389.05 0.16"' 389.21 j
Proiect File: Phase 2 Convevanoe.stm Vumber of lines:17 3ate: 5117.�1012
NOTES: ""Critical depth
?-:xri S:x�Y�i
��� rago"e
Vel Vel EGL J-Losa Minor EGL HGL GndtRlm Rirn-Hw
Up Hd Up Up Coeff Loss Jnct Jnct EI Up
(ws► In) In) (n) (n) (nl (n) lnl
4.52 0.32 388.16 1.00 0.32 388.48 388.16 396.10 7.94
4.33 0.29 388.62 0.76 0.22 388.85 388.55 395.10 6.55
4.33 0.29 389.44 0.24 0.07 389.51 389.22 395.75 6.53
4.33 0.29 390.56 0.85 0.25 390.80 390.51 396.01 5.50
1.73 0.05 390.67 0.23 0.01 390.68 390.64 396.25 5.61
3.51 0.19 393.03 0.15 n/a 393.03 392.83 396.29 3.46
3.51 0.19 393.84 0.89 n/a 393.84 393.64 397.01 3.37
3.51 0.19 394.25 0.89 n/a 394.25 394.05 398.80 4.75
3.51 0.19 407.19 1.00 n/a 407.19 406.99 411.33 4.34
2.89 0.13 390.76 0.44 0.06 390.82 390.69 395.59 4.90
3.52 0.19 391.20 0.23 n/a 391.20 391.01 396.46 5.45
3.39 0.18 391.49 1.00 0.18 391.67 391.49 395.93 4.44
3.29 0.17 394.16 1.00 n/a 394.16 393.99 396.75 2.76
2.22 0.08 392.09 0.92 n/a 392.09 392.01 396.11 4.10
2.12 0.07 394.50 1.00 n/a 394.50 394.43 397.43 3.00
1.25 0.02 393.91 1.00 n/a 393.91 393.88 396.33 2.45
1.76 0.05 389.26 1.00 n/a 38926 389.21 400.50 11.29
Prviect File: Phase 2 Convevanoe.stm Vumber of lines:17 �ate: 5117,+�61Z
NDTES: ""Griti[�I depth
�•:xrv S:-.�r�i
South Basin Conveyance Calculations
Conveyance calculations were performed using a conservative simplified method.The entire tributary area
for each conveyance line was summed up.The flows generated from the total tributary area are added to the
most upstream point in the conveyance system.
C�UGHLINPORTERLUNDEEN Lindbergh High School Improvements
Renton,VVashington
MGS FLOOD
PROJECT REPORT
Program Version: MGSFIood 4.12
Program License Number: 200610002
Run Date: 05I1712012 12:09 PM
Input File Name: South Basin Student Parking.fld
Project Name: Lindbergh HS
Analysis Title: Student Parking Conveyance
Comments:
PRECIPITATION INPUT
Computational Time Step(Minutes): 15
Extended Precipitation Timeseries Selected
Climatic Region Number: 13
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 **'`******"`**'`*'`******'`''
---------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Student Parking ----------
------Area(Acres) --------
Till Forest 3.423
Till Pasture 0.000
Till Grass 0.000
Outwash Forest 0.000
Outwash Pasture 0.000
Oufinrash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000 �
Impervious 0.000
Subbasin Total 3.423
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Student Parking ----------
------Area(Acres)--------
Till Forest 0.000
Till Pasture 0.000
Till Grass 0.163
Outwash Forest 0.000
Outwash Pasture 0.000
Outwash Grass 0.000
Wetland 0.000
Green Roof 0.000
User 0.000
Impervious 3.260
--------------------------------------------
Subbasin Total 3.423
******�***********�****** LIN K DATA*******�***********************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
�****�******************* LIN K DATA**.,�************��*************
--------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
**********************FLOOD FREQUENCY AND DURATION STATISTICS'`"***'F*'`***'"`***'`*"
---------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
--------------------SCENARIO: POSTDEVELOPED I
Number of Subbasins: 1
Number of Links: 0
''**"'"`*'"""`Water Quality Facility Data*********'``**
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
'"""******'Compliance Point Results**''*'"***'`***
Scenario Predeveloped Compliance Subbasin: Student Parking
Scenario Postdeveloped Compliance Subbasin: Student Parking
*** 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 0.073 2-Year 1.231
5-Year 0.119 5-Year 1.592
10-Year 0.160 10-Year 1.820
25-Year 0.203 25-Year 2.305
50-Year 0.259 50-Year 2.884
100-Year 0.281 100-Year 3.383
200-Year 0.437 200-Year 3.494
"` Record too Short to Compute Peak Discharge for These Recurrence Intervals
�-,
�
_ !
/��� Page'
V
Line Inlet Line DnStm Flow Line Line Line Line n-val Invert 3Epth HGL Vel Vel EGL HGL Invert }e�th HGL
No. ID ID Ln No Rate _ength Size Slops Type Pipe Dn Dn Dn Dn Hd Dn Dn Jmp Dn Up Up Up
(��) (n) (�n) (°�) (n) (n) (n) (ft/g) (n) (ft) (n) (ft) (ft) (ft)
1 �D#56 SD#56 to Ex SO�t55 Outfall 2.31 13 12 2.01 Cir 0.012 417.70 0.64 418.34 4.31 0.29 418.63 .... 417.96 0.64" 418.60
2 �D iM57 SD�.57 to SD l�5fi 1 2.31 46 12 6.46 Cir 0.012 417.96 0.64 418.60 4.31 0.29 418.89 .... 420.92 0.64"" 421.56
3 �b�k5B Sb ti5B ta SD#57 2 2.31 70 12 4.62 Cir 0.012 420.92 0.64 421.56 4.31 0.29 421.85 .... 424.15 0.64" 424.79
4 5D�k5U SD ii5Q to SD�i5B 3 2.31 66 12 2.18 Cir 0.012 424.15 0.64 424.79 4.31 0.29 425.08 .... 425.58 0.64"" 426.22
5 �D*6D SD�i&D to SD�i5�3 4 2.31 77 12 1.01 Cir 0.012 425.58 0.64 426.22 4.31 0.29 426.51 ... 426.35 0.64'" 426.99
6 SD�60u0. �d�+60u4 ro SD#60 5 2.31 61 12 1.07 Cir 0.012 426.35 0.64 426.99 4.31 0.29 427.28 .... 427.00 0.64'" 427.64
Prvject File: Near.sirn Vumber of lines:G �ate: 5117,�61 Z
NOTES: ""Gritiql depth
�•:��s:-...,
C P L P°g�;
Vel Vel EGL J-Loss Minor EGL HGL GndfRlm Rirn-Hw
Up Hd Up Up Coeff I.oss Jnct Jnct EI Up
(ws) (n) (n) (n1 (n) (ft) (ft) (nl
4.31 0.29 418.89 0.15 0.04 418.89 418.60 421.77 3.17
4.31 0.29 421.85 0.61 0.18 421.85 421.56 423.92 2.36
4.31 0.29 425.08 0.36 0.10 425.08 424.79 427.15 2.36
4.31 0.29 426.51 0.55 0.16 426.51 426.22 428.58 2.36
4.31 0.29 427.28 0.91 0.26 427.28 426.99 430.57 3.58
4.31 0.29 427.93 1.00 0.29 427.93 427.64 429.51 1.87
Project File: New.slrn Vumber ot lines:6 Date: S117,�lD12
NOTES: ""Gritical depth
�-:xr�S:.-.�x�
VI. SPECIAL REPORTS AND STUDIES
I. Subsurface Explowation Geologc Hazards and Preliminary Geotechnical Engineering Report• Renton.
Washington. Prepared by Associated Earth Sciences, Inc.on February 18,2010.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
2� Renwn,Washington
::,'
�j" �ir, `�t',��:=
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.
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Geotechnical Engineering Associated Ea.rth Sciences, TI1C.
�.:.�.:x._�
C'el���s�"y ave�,Z�' �e��sofJes�ice
���
� -��---:
_ . Subsurface Exploration, Geologic Hazards, and
Preliminary Geotechnical Engineering Report
Water Resources
; ,
LINDBERGH HIGH SCHOOL
` �x �``�� �� IMPROVEMENTS
� r:
_ Renton, Washington
F:�
=r, =.
J Pre ared for
P
Environmental Assessments and
Remediation Renton School District
c/o Greene Gasaway Architects, PLLC
.�f,
� # ' Project No. KE09Q426A
, February 18, 2010
Sustainable Develo+ ment Services
P
-, �
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,q -
,:; - -
�� -
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.::�:
Geologic Assessments
I
Associated Earth Sciences, Inc.
� a � �
Ce�hv���i�y C�ve�2��ea�a f.S'ev�ce
February 18, 2010
Pro.ject No. KE090426A
Renton School District
c/o Greene Gasaway Architects, PLL,C
P.O. Box 4158
Federal Way, Washington 98063
Attention: Mr. Calvin Gasaway
Subject: Subsurface Exploration, Geologic Hazards, and
Preliminary Geotechnical Engineering Report
Lindbergh High School Improvements
16426 128'� Avenue SE
Renton, Washington
Dear Mr. Gasaway:
We are pleased to present these copies of our preliminary report for the referenced project.
This report summarizes the results of our subsurface exploration, geologic hazards, and
geotechnical engineering studies, and offers preliminary recommendations for the design and
development of the proposed project. Our report is preliminary since project plans were under
development at the time this report was written. We should be allowed to review the
recommendations presented in this report and modify them, if needed, once final project plans
have matured.
We have enjoyed working with you on this stlidy and are confident that the recorruneildati�ns
presented in this report will aid in the successful completion of your project. If you sh��l�ld
have any questions or if we can be of additional help to yoli, nl�•�,�� ��, n��t 1����.ii��+i� i�� ��<<ll
Sincerely,
ASSOCI��CEU E:_�iZl�}{ ��:IEtiCI�:�. I�t
Kirkland, Washington
"��.y�t�.�,-=__��_...�
i ; Kurt D. Merriman, P.E.
i Principal Engineer
KDM/id-KE090426A3-Projects�2009047bUCE1WP
I � Kirkland ■ Everett ■ Tacoma
425-827-7701 425-259-0522 253-722-2992
www.aeseeo.com
SUBSURFACE EXPLORATION, GEnLOGIC HAZARDS, AND
PRELIMINARY GEOTECHNICAL ENGINEERING REPORT
'�
�
LINDBERGH HIGH SCHOOL
IMPROVEMENTS
Renton, Washington
Prepared for:
Renton School District
c/o Greene Gasaway Architects, PL,t,C
P.O. Box 4158
Federal Way, Washington 98063
f'i�cJl�ri�c�l b,,
Associated Earth Scienc��. In� .
911 5`h Avenue, Suite 100
Kirkland, Washington �-�'�',
- 425-827-7701
Fax: 425-827-54'
February 18, 2010
Praject No. KE090426A
Subsurface EYpinrntion, Geologic Hazards, and
Lindbergl:High School Improveraents Preliminary Geotech�sical Engineer•ing Reporl
Renton, Washingto�t Project and Site Conditions
I. PROJECT AND SITE CONDITIONS
1.0 INTRODUCTION
This report presents the results of our subsurface exploration, geologic hazards, and
preliminary geotechnical engineeruig studies for the proposecl improvements to Lindbergh
High School. The site location is shown on Figure 1, "Vicinity Map." The approximate
locations of the exploration borings completed for this study are shown on the "Site and
Exploration Plan," Figure 2. Logs of the subsurface explorations completed for this study are
included in the Appendix.
1.1 Purpose and Scope
The purpose of this study was to provide geotechnical engineering design recommendations to
be utilized in the preliminary design of the project. This study included a review of selected
available geologic literature, advancing 12 hollow-stem auger soil borings, and performing
geologic studies to assess the type, thickness, distribution, and physical properties of the
subsurface sediments and shallow ground water. Geotechnical engineering studies were
completed to establish recommendations for the type of suitable foundations and floors,
allowable foundation soil bearing pressure, anticipated foundation and floor settlement,
pavement recommendations, and drainage considerations. This report summarizes our
fieldwork and offers preliminary recommendations based on our present understanding of the
project. We recommend that we be allowed to review the recommendations presented in this ,
report and revise them, if needed, when a project design matures. II
1.2 Authorization
Written authorization to proceed with this study was granted by Mr. Rick Stracke of the
Renton School District No. 403 (District). Our study was accomplished in general accordance
with our scope of work letter dated November 18, 2009. This report has been prepared for the �
exclusive use of the District, Greene Gasaway Architects, PLLC, and their 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
otlier warranty, express or implied, is made. '
�
Fehniary I8, 2010 ASSOCIATED EARTH SClENCES, /NC.
lPL-(d-KEU90�J'6R3-Pro�ecrs'_009�J261KEIWP Page 1
Subsurface Eiploratiori, Geologic Hazards, ajtd
Lindbe�•gJz High Schoo!bnprnvements Prelintinary Geotechnical Engineering Reporl
Renton, Washington Project and Site Conditio�is
2.0 PROJECT AND SITE DESCRIPTION
This report is based on our understanding of the currently-proposed site improvements at
Lindbergh High School, It is our understanding that these improvements include construction
of a weight room addition to the gym, construction of a fire loop road, additional parking
areas, road widening, and repaving the upper parking lot. The areas currently proposed for
these improvements are covered with grass or existing paved surfaces. At the time this report
was written, no grading plan or detailed structural designs had been completed. For the
purpose of preparing this report, we have assumed the new structure and paved surfaces will
be constructed close to existing grades, and that the new structure will be a one- to two-story
building, with relatively light foundation loads.
The project site is that of the existing Lindbergh High School. The existing school includes
several buildings with paved parking areas and driveways. Grass athletic fields (baseball/
softball) are located to the west of the main structures, and a synthetic football field is located
to the southeast. The site has been graded to its current configuration by past earthwork
on-site. Overall site topography is that of a broad valley with a northwest-southeast trending
bottom, which slopes downward from the northwest to the southeast. Site grades are generally
relatively flat to moderately sloping within the areas proposed for construction, with a fe��
limited steeply-sloping areas, which are likely the result of past grading (e.g., along the "homr
� run" fence of the basel��.:L t� ;,_���, T,,._ �Tin� ; ,��� .�r� ������ .���;�:�.r���'. ��, t,�_ ,!,;__ ;,�
,.,. �
.. . � . :, _ . .. . ,.
3.0 SUBSURFACE EXPLORATIO.�
Our subsurface exploration completed for this project included advanciiig 12 hollow-ste�
auger soil borings. Other borings have been completed by Associated Earth Sciences, I��
(AESI) throughout the school property during previous studies conducted at the subject sii
One boring from these past studies, exploration boring EB-7 (completed in January of 2003�,
has been included with the recent boruig logs in the attached Appendix because it is located
along the approximate alignment of the proposed fire lane. In this report, for the purposes of
clarity, we have renamed this boring "EB-7A." The conclusions and recommendations
presented in this report are based on the explorations completed for this study. The locations
and depths of the explorations were completed within site and budget constraints.
3.1 Exploration Borings
The exploration borings were completed by advancing hollow-stem auger tools with a track-
mounted drill rig. During the drilling process, samples were obtained at generally 2.5- to
5-foot-depth intervals. The exploration bori�igs were continuously observed and logged by a
Februa�y 18, 2010 ASSOCIATED EARTH SCIENCES, INC
1P11Id-KF_090�J_'6.t3-Projeusl'0�90a'6�KE�WP Page 2
Subsu�fnce Erplorntion, Geologir. Hazards, c�nd
Lindbergh Hig/i Sdiool lmprovements Prelir�iinary Geotechnical Engirieering Report
Renton, Was{iington Project and Site Conditions
representative from our firm. The exploration logs presented in the Appendix are based on the
field logs, drilling action, and inspection of the samples secured.
Disturbed, but representative samples were obtained by using the Standard Penetration Test
(SPT) procedure in accordance with American Society for Testing and Materials
(ASTM):D 158b. 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, 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 visuai classification.
4.0 SUBSURFACE CONDITIONS
- Subsurface conditions at the project site were inferred from the field explorations accomplished
for this study, visual recannaissance of the site, and review of selected applicable geologic
literature. Because of the nature of exploratory work below ground, interpolation of
subsurface conditions between field explorations is necessary. It should be noted that differing
subsurface conditions may sometimes be present due to the random nature of deposition and
the alteration af topography by past grading and/or filling. The nature and extent of any
variations between the field explorations may not become fully evident until construction.
4.1 Stratigraphy
Fill
Existing fill was encountered in exploration borings EB-1 through EB-4, EB-6, and EB-9
through EB-12, as well as in exploration boring EB-7A, to depths ranging of up to
approximately 13 feet below the existing ground surface. The encountered fill exhibited a
wide range of soil densities, and appeared to consist of materials derived on-site and moved or
disturbed during earlier site work. The fill generally contained trace amounts of organics,
although abundant organic material, which appeared to be derived from pre-existing topsoil,
was observed in EB-4. Exploration boring EB-2, located near to the top of a grassy slope
adjacent to the baseball field, encountered approximately 8 feet of fill, possibly placed during
the grading for the field, above the elevation of the nearby driveway. Due to the variability in
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Renton, Washington Project and Site Conditiais
density, the existing fill will require removal from building areas and remedial improvement
below planned paving.
Ice Coritact Deposits
Below the existing fill, exploration borings EB-1 through EB-4, and EB-12 encountered
variable silty sand with gravel, interbedded in places with fine sand zones or silt seams.
Density typically varied from medium dense to dense, increasing to very dense within zones
containing increased amounts of gravel. These native sediments are interpreted to represe�it
Vashon ice contact sediments. Ice contact sediments were initially deposited above or within a
glacial ice mass, and were subsequently redeposited when the ice melted. Ice contact
sediments can be stratified and alluvially re-worked, and stratification was noted in our
exploration borings on this site. Ice contact deposits are typically not consolidated to the same
degree as lodgement till sediments, though some degree of compaction by glacial activity cac�
occur. The ice contact sediments observed in our exploration borings for this project are sil«
and are considered highly moisture-sensitive. With proper preparation, these sediments will
provide adequate support for the new building addition or paved surfacing. Excavated ic�
contact sediments are expected to be above optimum moisture content for compactic�r�
purposes, and will need to be dried during favorable dry site and weather conditions to allo� .
their reuse in structural fill applications. At the locations of exploration borings EB-1 throu��
EB-4, the ice c
15.5 to 21.5 fe
Vashon Lodgeme�it Till
Sediments encountered at exploration borings EB-5 through EB-11, below the ice contact
sediments at the location of exploration boring EB-12, and in exploration boring EB-7A,
consisted chiefly of dense to very dense, silty sand with gravel. We interpret these sediments
to be representative of Vashon lodgement till. The Vashon lodgement till was deposited
directly from basal, debris-laden glacial ice during the Vashon Stade of the Fraser Glaciation
approximately 12,500 to 15,000 years ago. The high relative density of the unweathered till is
due to its consolidation by the massive weight of the glacial ice from which it was deposited.
At the locations of EB-5 through EB-12, and EB-7A, the till extended beyond the maximum
depths explored of approximately 10.3 to 16.5 feet.
4.2 Geologic Mapping
We reviewed a published geologic map of the area (Geologic Map of King Counry,
Wc�shington, by Derek B. Booth, Kathy A. Troost, and Aaron P. Wisher, 2006). The
referenced map indicates that the site vicinity is characterized primarily by lodgement till at the
ground surface. The shallow native sediments observed iii our explorations for this project are
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Renton, Washington Project muf Site Condicions
�
not entirely consistent with this mapping, although lodgement till was encountered. It is not
unusual to find localized areas that vary from published regional scale geologic mapping, and
that is the case with this site. Ice contact sediments occur regularly in the project area above
lodgement till. We recommend that design activities for this project be based on subsurface
materials observed in our on-site explorations.
4.3 Hydrolo�y
Two of the exploration borings encountered ground water seepage, typically originating from
granular horizons within the ice contact sediments. We expect ground water seepage across
much of the site to be limited to interflow. Interflow occurs wheii surface water percolates
down through the sur�cial weathered or higher-permeability sediments and becomes perched
atop underlying, lower-permeability sediments. Based on site topography, we expect that this
interflow will tend to flow from the relatively higher northeast and southwest portions of the
site and collect below the central northwest-southeast trending valley bottom. It should be
noted that the occurrence and level of ground water seepage at the site may vary in response to
such factors as changes in season, precipitation, and site use.
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Reruon, Wcrshington Geologic Hazards mid Mitigations
I II. GEOLOGIC HAZARDS AND MITIGATIONS
The following discussion of potential geologic hazards is based on the geologic, slope, and
ground and surface water conditions, as observed and discussed herein. The discussion will be
limited to seismic and erosion issues.
5.0 SEISMIC HAZARDS AND MITIGATIONS
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 2001, 6.$-magnitude event; and the 1965, 6.5-magnitude
event. 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 four types of potential geologic hazards associated with large seismic
; events: 1) surficial ground rupture, 2) seismically induced landslides, 3) liquefaction, and
4) ground motion. The potential for each of these hazards to adversely impact the proposed
project is discussed below.
5.1 Surficial Ground Rupture
The subject site is located approximately 5 miles to the south of the Seattle Fault Zone. Recent
studies by the United States Geological Survey (USGS) (e.g., Johnson, et al., 1994, Origin
and Evolaction of the Seattle Fault an�i Seattle Basin, Washington, Geology, v. 22, p.71-74;
and Johnson et al., 1999, Active Tectonics of the Seattle Fc�ult and Centrad Puget Soa�nd
Waslzington - Implications for Earthquake Hazards, Geological Society of America Bulletin,
July 1999, v. 111, n. 7, p. 1042-1053) have provided evidence of surficial ground rupture
along a northern splay of the Seattle Fault. The recognition of this fault is relatively new, and
data pertaining to it are limited, with the studies still ongoing. According to the USGS studies,
the latest movement of this fault was about 1,100 years ago when about 20 feet of surficial
displacement took place. This displacement can presently be seen in the form of raised, wave-
cut beach terraces along Alki Point in West Seattle and Restoration Point at the south end of
Bainbridge Island. The recurrence interval of movement along this fault system is still
unknown, although it is hypothesized to be in excess of several thousand years. Due to the
suspected long recurrence interval, the potential for surficial ground rupture is considered to be
low during the expected life of the structures, and no mitigation efforts beyond cornplying with
the current (2006) Ifztet�t2ational Ba�ildi�zg Code (IBC) are recommended.
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Renton, WQSIIIl2gf0)1 Geologic Hazards a�ut Mttigatio�is
5.2 Seismically Induced Landslides
The lodgement till is a high shear strength, relatively low-permeability material and is not
overly sensitive to landsliding given the topographic conditions at the site. In addition, no
evidence of historical landslide activity was observed, such as landslide scarps, hummocky
topography, tension cracks, or unusually distorted or leaning tree trunks. Given the subsurface
and topographic conditions within and adjacent to the proposed development area and the
apparent lack of historical landslide activity, it is our opinion that the risk of damage to the
proposed project by landsliding under either static or seismic conditions is low. This opinion
is dependent upon site grading and construction practices being completed in accordance with
the geotechnical recommendations presented in this report.
5.3 Liquefaction
Liquefaction is a process through which unconsolidated soil loses strength as a result of
vibrations, such as those which occur during a seismic event. During normal conditions, the
weight of the soil is supported by both grain-to-grain contacts and by the fluid pressure within
the pore spaces of the soil below the water table. Extreme vibratory shaking can disrupt the
grain-to-grain contact, increase the pore pressure, and result in a temporary decrease in soil
shear strength. The soil is said to be liquefied when nearly alt of the weight of the soil is
supported by pore pressure alone. Liquefaction can result in deformation of the sediment and
settlement of overlying structures. Areas most susceptible to liquefaction include those areas
underlain by non-cohesive silt and sand with low relative densities, accompanied by a shallow
water table.
The subsurface conditions encountered at the site pose little risk of liquefaction due to
relatively high density and lack of shallow ground water. No detailed liquefaction analysis was
completed as part of this study, and none is warranted, in our opinion,
5.4 Ground Motion
It is our opinion that any earthquake damage to the proposed structure, when founded on a
suitable bearing stratum in accordance with the recommendations contained herein, will be
caused by the intensity and acceleration associated with the event and not any of the above-
discussed impacts. Structural design of the proposed building should follow the 2006 IBC.
Information presented by the USGS Earthquake Hazards Program indicates a spectral
acceleration for the project area for short periods (0.2 seconds) of Ss = 1.364 and for a
1-second period of S� = 0.465. Based on the results of subsurface exploration and on an
estimation of soil properties at depth utilizing available geologic data, Site Class "C", in
conformance with Table 1613.5.2 of the IBC, may be used.
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Liridbergh High Sclsool Improveme�its Preliminary Geotechnical E�igineering Rep�:�
Re�uon, Washi�agton Geologic Hazards and Mitigatio�
6.0 EROSION HAZARDS AND MITIGATIONS
' As of October 1, 2008, the Washington State De�-.�,�...�.., �:� � �:��,_��. ,,�.�. ;;��, ; �_ .�,,�„�."�
Storm Water General Permit (also known as the National Pollutant Discharge Eliminatic�
System [NPDES] permit) requires weekly Temporary Erosion and Sedimentation Contr�
(TESC) inspections and turbidity monitoring of site runoff for all sites 1 or more acres in sir
that discharge storm water to surface waters of the state. We provide in the following sectior:
recommendations to address these inspection and reporting requirements. The followir:
sections also include recommendations related to general erosion control and mitigation.
The TESC inspections and turbidity monitoring of runoff must be completed by a Certified
Erosion and Sediment Control Lead (CESCL) for the duration of the construction. The weekly
'_ TESC reports do not need to be sent to Ecalogy, but should be logged into the project Storm
Water Pollution Prevention Plan (SWPPP). Ecology requires a monthly summary report of the
turbidity monitoring results signed by the NPDES permit holder. If the monitored turbidity
equals or exceeds 25 nephelometric turbidity units (NTU) (Ecology benchmark standard), the
project best management practices (BMPs) should be modified to decrease the turbidity of
storm water leaving the site. Changes and upgrades to the BMPs should be documented in the
weekly TESC reports and continued until the weekly turbidity reading is 25 NTU or lower. If
the monitored turbidity exceeds 250 NTU, the results must be reported to Ecology via phone
within 24 hours and corrective actions should be implemented as soon as possible. Daily
- turbidity monitoring is continued until the corrective actions lowers the turbidity to below
25 NTU, or until the discharge stops. This description of the sampling benchmarks and
reporting requirements is a brief summary of the Construction Storm Water General Permit
conditions. The general permit is available on the internetl.
In order to meet the current Ecology requirements, a properly developed, constructed, and
_ maintained erosion control plan consistent with City of Renton standards and best management
erosion control practices will be required for this project. AESI is available to assist the
project civil engineer in developing site-specific erosion control plans. Based on past
experience, it will be necessary to make adjustments and provide additional measures to the
, TESC plan in order to optimize its effectiveness. Ultimately, the success of the TESC plan
depends on a proactive approach to project planning and contractor implementation and
maintenance.
The most effective erosion control measure is the maintenance of adequate ground cover.
Maintaining cover measures atop disturbed ground provides the greatest reduction to the
potential generation of turbid runoff and sediment transport. During the local wet season
(October 1S` through March 3151), exposed soil should not remain uncovered for more than
2 days unless it is actively being worked. Ground-cover measures can include erosion control
� h[tp://www.ecy.wa.gov/progran�slwqlstormwater/construction/constructionfinalpermit.pdf
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Lindbergh High School lmprovements Prelilninary Geotechnicnl Engineering Reporr
Renton, Washirtgton Geologic Hazards and Mitigatia�
matting, plastic sheetin_ ' ; , � , � ,
. 1, .� ..
��.. :_..._ ._...... . .,[; �� .���.. .:i_ _. _ __. . 1-.. ;� _ � ��il_��t�:�_ .,�: . . ,_. .__ �!i�. _
runoff. Flow paths across slopes should be kept to less than 50 feet in order to reduce th�
erosion and sediment transport potential of concentrated flow. Ditch/swale spacing will nee�l
to be shortened with increasing slope gradient. Ditches and swales that exceed a gradient c>t
about 7 to 10 percent, depending on their flow length, should have properly constructed chec�:
dams installed to reduce the flow velocity of the runoff and reduce the erosion potential withi��
the ditch. Flow paths that are required to be constructed on gradients between 10 to 15 perce���
should be placed in a riprap-lined swale with the riprap properly sized for the anticipated flo��
conditions. Flow paths constructed on slope gradients steeper than 15 percent should be placec]
in a pipe slope drain. AESI is available to assist the project civil enairieer in developinQ ��
suitable erosion control plan with proper flow control
With respect to water quality, having ground cover pri��r <<� ra��� � ������ �> ���c ui �i�:: �,.��
important and effective means to maintain water quality. �nce very fine sediment is suspendt I
in water, the settling times of the smallest particles are on the order of weeks and month ',
Therefore, the typical retention times of sediment traps or ponds will not reduce the turbidi,_
of highly turbid site runoff to the benchmark turbidity of 25 NTU. Reduction of turbidity from
a construction site is almost entirely a function of cover measures and drainage control that
have been implemented prior to rain events. Temporary sediment traps and ponds are
' necessary to control the release rate of the runaff and to provide a catchment for sand-sized
and larger soil particles, but are very ineffective at reducing the turbidity of the runoff.
Silt fencing sh�uld be utilized as buffer protection and not as a flow-control measure. Silt
fencing is meant to be placed parallel with topographic contours to prevent sediment-laden
runoff from leaving a work area or entering a sensitive area. Silt fences should not be placed
to cross contour lines without having separate flow control in front of the silt fence.
A swale/berm combination should be constructed to provide flow control rather than let the
runoff build up behind the silt fence and utilize the silt fence as the flow-control measure.
Runoff flowing in front of a silt fence will cause additional erosion and usually will cause a
failure of the silt fence. Improperly installed silt fencing has the potential to cause a much
larger erosion hazard than if the silt fence was not installed at all. The use of silt fencing
should be limited to protect sensitive areas, and swales shauid be used to provide flow control.
6.1 Erosion Hazard Mitigation
To mitigate the erosion hazards and potential for off-site sediment traiisport, we would
reconunend the following:
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Renron, Was{iington Geologic Hazards and Mitigations
1. Construction activity should be scheduled or phased as much as possible to reduce the
amount of earthwork activity that is performed during the winter months.
2. The winter performance of a site is dependent on a well-conceived plan for control of
site erosion and storm water runoff. It is easier to keep the soil on the ground than to
remove it from storm water. The owner and the design team should include adequate
ground-cover measures, access roads, and staging areas in the project bid to give the
selected contractor a workable site. The selected contractor needs to be prepared to
implement and maintain the required measures to reduce the amount of exposed
ground. A site maintenance plan should be in place in the event storm water turbidity
measurements are greater than the Ecology standards.
3. TESC measures for a given area to be graded or otherwise worked should be installed
soon after ground clearing or timber harvesting. The recommended sequence of
construction within a given area after clearing/timber harvesting would be to
install sediment traps and!or ponds and estahlish perimeter flow control prior to startina
mass grading.
4. During the wet��r ilionth5 uT the year, ur wtien large swriti events are pre�lictecl clui>>
the summer months, each work area should be stabilized so that if showers occur, tl
work area can receive the rainfall without excessive erosion or sediment transport. TI:.
required measures for an area to be "buttoned-up" will depend on the tune of year an�
the duration the area will be left un-worked. During the winter months, areas that ar�
to be left un-worked for more than 2 days should be mulched or covered with plastic.
During the summer months, stabilization will usually consist of seal-rolling the
subgrade. Such measures will aid in the contractor's ability to get back into a work
area after a storm event. The stabilization process also includes establishing temporary
storm water conveyance channels through work areas to route runoff to the approved
treatment facilities.
5. All disturbed areas should be revegetated as soon as possible. If it is outside of the
growing season, the disturbed areas should be covered with mulch, as recommended in
the erosion control plan. Straw mulch provides a cost-effective cover measure and can
be made wind-resistant with the application of a tackifier after it is placed.
6. Surface runoff and discharge should be controlled during and following development.
Uncontrolled discharge may promote erosion and sediment transport. Under no
circumstances should concentrated discharges be allowed to flow over the top of
steep slopes.
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Subsurface Fa:plof•atiai, Geologic Hazards, aiid
Lind6ergh High School lmp�•ovements Prelirninary Gentechnical Engineering Renorr
Re�iton, Washi�igton Geologic Hazards atuf Mitigatio�ts
7. Soils that are to be reused around the site should be stored in such a manner as to
i reduce erosion from the stockpile. Protective measures may include, but are not
, limited to, covering with plastic sheeting, the use of low stockpiles in flat areas, or the
use of silt fences around pile perimeters. During the period between October 1S1 and
March 315t, these measures are required.
8. On-site erosion control inspections and turbidity monitoring (if required) should be
performed in accordance with Ecology requirements. Weekly and monthly reporting to
Ecology should be performed on a regularly scheduled basis. A discussion of
temporary erosion control and site runoff monitoring should be part of the weekl}�
construction team meetings. Temporary and permanent erosion control and drainage
measures should be adjusted and maintained, as necessary, for the duration of project
constructio n
It is our opinion that witl� the proper iiiipletnentation uT the �I��,SC plans ancl by� Tielci-a�ijustin��
appropriate mitigation elements (BMPs) throughout construction, as recommended by th�
, erosion control inspector, the potential adverse impacts from erosion hazards on the pr��i���l
:1_��. ����_._.. _,,
I
I
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Renton, Washington Preliminary Design Reconune�utations
III. PRELIMINARY DESIGN RECOMMENDATIONS
7.0 INTRODUCTION
Portions of the subject site are underlain by a layer of surficial existing fill that is variable in
density, composition, and thickness. Existing fill is not suitable for support of new
foundations, and warrants remedial preparation where it occurs below paving and similar
lightly loaded structures. Structural fill or native ice contact or lodgement till deposits are
suitable for support of shallow foundations with proper preparation. Based on the soil
conditions encountered in exploration boring EB-5, we anticipate that overexcavation will not
be necessary for the foundations for the proposed weight room addition to the gym. This
should be verified during construction.
8.0 SITE PREPARATION
Existing buried utilities, vegetation, topsoil, and any other deleterious materials should be
removed where they are located below planned construction areas. All disturbed soils resulting
from demolition activities should be removed to expose underlying, undisturbed, native
sediments and replaced with structural fill, as needed. All excavations below final grade made
for demolition activities should be backfilled, as needed, with structural fill. Erosion and '�,
surface water control should be established around the clearing limits to satisfy local ,
requirements. I�
Once demolition has been completed, existing fill should be addressed. The observed fill
depth in our borings was up to approximately 13 feet below existing grade. We recommend
that existing �11 be removed from below areas of planned foundations to expose underlying
undisturbed native sediments, followed by restoration of the planned foundation grade with '
structural fill. Removal of existing fill should extend laterally beyond the building footprint by '
a distance equal to the depth of overexcavation. For example, if existing �11 is removed to a �
depth of 2 feet below a planned footing area, the excavation should also extend laterally 2 feet
beyond the building footprint in that area. Care should be taken not to disturb support soils of
existing foundations. Support soils should be considered those soils within a prism projected �
downward and outward from existing footings at inclinations of 1H:1V (Horizontal:Vertical). �
Where existing fill is removed and replaced with structural fill, conventional shallow
foundations may be used for building support. The required depth of removal should be
determined in the field based on actual conditions encountered during excavation.
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Re�uori, Waslttngton Preliminary Design Recommendatiau
8.1 Site DrainaQe and Surface Water Control
The site should be graded to prevent water from ponding in construction areas and/or flowing
into excavations. Exposed grades should be crowned, sloped, and smooth-drum rolled at the
end of each day to facilitate drainage. Accumulated water must be removed from subgrades
and work areas immediately prior to performing further work in the area. Equipment access
may be limited, and the amount of soil rendered unfit for use as structural fill may be greatly
increased if drainage efforts are not accomplished in a timely sequence. If an effective
drainage system is not utilized, project delays and increased costs could be incurred due to the
greater quantities of wet and unsuitable fill, or poor access and unstable conditions.
Our exploration borings encountered evidence of seasonal ground water seepage from granular
intervals within the ice contact deposits. We also anticipate that perched ground water could
be encountered in excavations completed during construction. We do not anticipate the need
for extensive dewatering in advance of excavations. The contractor should be prepared to
intercept any ground water seepage entering the excavations and route it to a suitable discharge
location.
Final exterior grades should promote free and positive drainage away from the buildings at all
times. Water must not be allowed to pond or to collect adjacent to foundations or within the
immediate building area. We recommend that a gradient of at least 3 percent for a minimum
distance of 10 feet from the building perimeters be provided, except in paved locations. In
paved locations, a minimum gradient of 1 percent should be provided, unless provisions are '
included for collection and disposal of surface water adjacent to the structures.
8.2 Subgrade Protection
To the extent that it is possible, existing pavement should be used for construction staging I
areas. If building construction will proceed during the winter, we recommend the use of a
working surface of sand and gravel, crushed rock, or quarry spalls to protect exposed soils,
particularly in areas supporting concentrated equipment traffic. In winter construction staging ,
areas and areas that will be subjected to repeated heavy loads, such as those that occur during I
construction of masonry walls, a minimum thickness of 12 inches of quarry spalls or 18 inches j
of pit run sand and gravel is recommended. If subgrade conditions are soft and silty, a
geotextile separation fabric, such as Mirafi SOOx or approved equivalent, should be used
between the subgrade and the new fill. For building pads where floor slabs and foundation
construction will be completed in the winter, a similar working surface should be used,
composed of at least 6 inches of pit run sand and gravel or crushed rock. Construction of
working surfaces from advancing fill pads could be used to avoid directly exposing the
subgrade soils to vehicular traffic.
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Rentai, Washington Preliminary Design Recommenda[ions
Foundation subgrades may require protection from foot and equipment traffic and ponding of
runoff during wet weather conditions. Typically, compacted crushed rock or a lean-mix
concrete mat placed over a properly prepared subgrade provides adequate subgrade protection.
Foundation concrete should be placed and excavations backfilled as soon as possible to protect
the bearing surface.
8.3 Proof-Rolling and Subgrade Compaction
Following the recommended demolition, site stripping, and planned excavation, the stripped
subgrade within the building areas should be proof-rolled with heavy, rubber-tired construction
equipment, such as a fully loaded, tandem-axle dump truck. Proof-rolling should be
performed prior to structural fill placement or foundation excavation. The proof-roll should be
monitored by the geotechnical engineer so that any soft or yielding subgrade soils can be
identified. Any soft/loose, yielding soils should be removed to a stable subgrade. The
subgrade should then be scarified, adjusted in moisture content, and recompacted to the
required density. Proof-rolling should only be attempted if soil moisture contents are at or
near optimum moisture content. Proof-rolling of wet subgrades could result in further
degradation. Low areas and excavations may then be raised to the planned finished grade with
compacted structural fill. Subgrade preparation and selection, placement, and compaction of
structural fill should be performed under engineering-controlled conditions in accordance with
the project specifications.
8.4 Overexcavation/Stabilization
Construction during extended wet weather periods could create the need to overexcavate
exposed soils if they become disturbed and cannot be recompacted due to elevated moisture
content and/or weather conditions. Even during dry weather periods, soft/wet soils, which
may need to be overexcavated, may be encountered in some portions of the site. If
overexcavation is necessary, it should be confirmed through continuous observation and testing
by AESI. Soils that have become unstable may require remedial measures in the form of one
or more of the following:
l. Drying and recompaction. Selective drying may be accomplished b} scarif��iilg c�i-
windrowing surficial material during extended periods of dr� an�l ��arn� ��.�ach�:r
2. Removal of affected s� :, . _ :. ,,.� �_ , ,. :.. . , :
compacted structural fi
3. Mechanical stabilization with a coarse �:ru�i���l a,���r���at� .:��n�pac���l ��ltu �l�c �uh�r_i�i��.
possibly in conjunction with a geotextile.
4. Soil/cement admixture stabilization.
Febructry 18, 2010 ASSOCIATED EARTH SCIENCES, /NC.
JPL/!d-KE090d36i1.�-Projecrsl200904?6iKElWP Page 14
Suhsc�rface Exploratiori, Geologic Hazards, and
I,i�idbergh High Sc/tool!►nprovements Preliminary Geotechnical Ei:gineering Repa�t
Reliton, Was/zi�:gton Preliminary Design Recommendatio�is
8.5 Wet Weather Conditions
If construction proceeds during an extended wet weather construction period and the moisture-
sensitive site soils become wet, they will become unstable. Therefore, the bids for site grading
operations should be based upon the time of year that construction will proceed. It is expected
that in wet conditions additional soils may need to be removed and/or other stabilization methods
used, such as a coarse crushed rock working mat to develop a stable condition if silty subgrade
soils are disturbed in the presence of excess moisture. The severity of construction disturbance
will be dependent, in part, on the precautions that are taken by the contractor to protect the
moisture- and disturbance-sensitive site soils. If overexcavation is necessary, it should be
confirmed through continuous observation and testing by a representative of our firm.
8.6 Temporary and Permanent Cut Slopes
In our opinion, stable construction slopes should be the responsibility of the contractor and
should be determined during construction. For estimating purposes, however, we anticipate
that temporary, unsupported cut slopes in the existing fill can be made at a maximum slope of
1.SH:1V or flatter, Temporary slopes in ice contact or lodgement till deposits may be planned
at 1H:1V. As is typical with earthwork operations, some sloughing and raveling may occur,
and cut slopes may have to be adjusted in the field. If ground water seepage is encountered in
cut slopes, or if surface water is not routed away from temporary cut slope faces, flatter slopes
will be required. In addition, WISHA/OSHA regulations should be followed at all times.
Permanent cut and structural fill slopes that are not intended to be exposed to surface water
should be designed at inclinations of 2H:1V or flatter. All permanent cut or fill slopes should
be compacted to at least 95 percent of the modified Proctor maximum dry density, as
determined by ASTM:D 1557, and the slopes should be protected from erosion by sheet plastic
until vegetation cover can be established during favorable weather.
8.7 Frozen Subgrades i
If earthwork takes place during freezing conditions, all exposed subgrades should be allowed to I
thaw and then be recompacted prior to placing subsequent lifts of structural fill or foundation
components. Alternatively, the frozen material could be stripped from the subgrade to reveal '
unfrozen soil prior to placing subsequent lifts of fill or foundation components. 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.
February 18, 2010 ASSOCIATED EARTH SC/ENCES. lNC.
JPLIId-KE09P4?6.13-Projecls120�0904161KE1WP Page 15
Subsurface F.xploratiolt, Geologic Hcuards, mul
Li�ufbergh High School lntprovements Preliminary Geotechnical Engineering Report
Renton, Wnshington Prelintinary Design Reco►nuiendalions
9.0 STRUCTURAL FILL
All references to structural fill in this report refer to subgrade preparation, fill type and
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.
After stripping, planned excavation, and any required overexcavation have been performed to
the satisfaction of the geotechnical engineer, the upper 12 inches of exposed ground in areas to
receive fill should be recompacted to 90 percent of the modified Proctor maximum density
using ASTM:D 1557 as the standard. If the subgrade contains silty soils and too much
moisture, adequate recompaction may be difficult or impossible to obtain and should probably
not be attempted. In lieu of recompaction, the area to receive fill should be blanketed with
washed rock or quarry spalls to act as a capillary break between the new fill and the wet
subgrade. Where the exposed ground remains soft and further overexcavation is impractical,
placement of an engineering stabilization fabric may be necessary to prevent contamination of
the free-draining layer by silt migration from below.
After recompaction of the exposed ground is tested and approved, or a free-draining rock
course is laid, structural fill may be placed to attain desired grades. 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 95 percent of the modified Proctor maximum 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 current City of Renton codes and
standards. The top of the compacted fill should extend horizontally outward a minimum
distance of 3 feet beyond the locations of the roadway edges before sloping down at an angle
of 2H:1V. I
The contractor should note that any proposed fill soils must be evaluated by AESI prior to their
use in fills. This would require that we have a sample of the material 72 hours in advance 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 should be limited to favorable dry weather
conditions. The native and existing fill soils present on-site contained variable amounts of silt
and are considered moisture-sensitive. In addition, construction equipment traversing the site
when the soils are wet can cause considerable disturbance. If fill is placed during wet weather
or if proper compaction cannot be obtained, a select import material consisting of a clean, free-
draining gravel andlor 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 with at least 25 percent retained on the No. 4 sieve.
February 18, 2010 ASSOCIATED EARTH SCIENCES, lNC.
1PLild-KL090-!?6.1.?-ProjeUs'_'0090a'6iKL•IWP Page 16
Subsurface F.�ploration, Geologic Hazards, and
Liridbergh High School lmprovements Preliininary Geotechnical Engineering Report
Re�ttori, Waslti�igton Prelimi�tary Desig�i Recanme�:datiofu
A representative from our firm should inspect the stripped subgrade 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 District in developing a
suitable monitoring and testing program.
10.0 FOUNDATIONS
Spread footings may be used for building support when founded directly on undisturbed ice
contact or lodgement till deposits or on structural fill placed above suitable native deposits, as
previously discussed. We recommend that an allowable bearing pressure of 3,000 pounds per
square foot (psfl be used for design purposes, including both dead and live loads. An increase
of one-third may be used for short-term wind or seismic loading. Higher foundation soil
bearing pressures are possible for foundations supported entirely on undisturbed or lodgement
till deposits; however, we do not expect that higher bearing pressures will be needed. If
higher foundation soil bearing pressures are needed, we should be allowed to offer situation-
specific recommendations.
Perimeter footings sliould be buried at least 1$ 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. Based on the soil conditions
encountered in exploration boring EB-5, we anticipate that overexcavation will not be
necessary for the foundations for the proposed weight room addition to the gym. This should
be verified during construction. 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.
Anticipated settlement of footings founded as described above should be on the order of �/a inch
or less. However, 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 ta 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.
l' N .. II
Februa�y 18, 2010 ASSOCIATED EARTH SCIEN,ES, ! C
JPt/!d-KLoA�4�6.4�-Pro�errs�70(�0�1?61KE�.ti'P Page 17
Subsurface Exploration, Geologic Hazards, and
Lir�dbergh High School Improvements Preliminary Geoteclinical E�:giriee�ing Report
Rento�i, Washington Preliminary Design Recanmendatio�:s
Care should be exercised when constructing new foundations adjacent to existing building
foundations. If possible, the new foundations should be founded at the same elevation as the
existing. If new footings are founded above existing footings, they will impart new loads that
may lead to settlement of the existing footings. If adjacent foundations are to be founded at
different elevations, the structural engineer should review the effect of the new loads on
foundations and stem walls. If new foundations will be placed below existing footing
elevations, the existing elements may need to be underpinned.
If any part of the excavations will intersect a 45-degree line extended down from the base of
the existing building foundation, then that portion of the excavation should be completed and
backfilled in short segments on the order of 5 to 10 feet in length. Care should be taken so as
not to undermine the existing foundation elements.
Consideration should be given to deferring the installation of a settlement-sensitive finish, as
long as practical, especially at the transition from the new weight room to the existing
building. To further reduce the potential for differential movement, a closure pour strip
between the new and existing floors could be deferred until the new dead loads are in place.
10.1 Drainage Considerations
Foundations should be provided with foundation drains placed at the base of footing elevation.
Drains should consist of rigid, perforated, polyvinyl chloride (PVC) pipe surrounded by
washed pea gravel. The drains should be constructed with sufficient gradient to allow gravity
discharge away from the proposed buildings. Roof and surface runoff should not discharge i
into the footing drain system, but should be handled by a separate, rigid, tightline drain. In �
planning, exterior grades adjacent to walls should be sloped downward away from the
proposed structures to achieve surface drainage.
11.0 FLOOR SUPPORT
Floor slabs can be supported on suitable native sediments, or on structural fill placed above '
suitable native sediments. Floor slabs should be cast atop a minimum of 4 inches of clean, I
washed, crushed rock or pea gravel to act as a capillary break. Areas of subgrade that are
disturbed (loosened) during construction should be compacted to a non-yielding condition prior
to placement of capillary break material. Floor slabs should also be protected from dampness
by an impervious moisture barrier at least 10 mils thick. The moisture barrier should be
placed between the capillary break material and the concrete slab.
� February 18, 2010 ASSOCIATED EARTH SCIENCES, INC.
JPL/!G-KE0904?6A3-Pro�ecrs1300A94361KEIWP Page 18
S�chsurface Exploration, Geologic Hazards, arid
Li�tdhergh High School Iniproveme�us Prelimi�iary Geotechnical Engineering Report
Renton, Washington Preliminar�j Design Recom�neridatio►is
12.0 FOUNDATION WALLS
All backfill behind foundation walls or around foundation units should be placed as per our
recommendations for structural fill and as described in this section of the report. Horizontally
backfilled walls, which are free to yield laterally at least 0.1 percent of their height, may be
designed using an equivalent fluid equal to 35 pounds per cubic foot (pc�. Fully restrained,
horizontally backfilled, rigid walls that cannot yield should be designed for an equivalent fluid
of 50 pcf. Walls with sloping backfill up to a maximum gradient of 2H:1V should be designed
using an equivalent fluid of SS pcf for yielding conditions or 75 pcf for fully restrained
conditions. If parking areas are adjacent to walls, a surcharge eqliivalent t� 2 feet of soil
should be added to the wall height in determining lateral design force�.
As required by the 2006 IBC, retaining wall design should include a seismic surcharge
pressure in addition to the equivalent fluid pressures presented above. Considering the sitr
soils and the recommended wall backfill materials> we recommend a seismic surchar���•
pressure of SH and lOH psf, where H is the wall height in feet for the "active" and "at-rest
loading conditions, respectively. The seismic surcharge sh�uld be modeled as a rectan,�ul:
distribution with the resultant applied at the mid-p
The lateral pressures presented above are bas�:.. .. ...� �.,:.�.�;.:.,:, . . .. ....... .... . .."..
consisting of excavated on-site soils, or imported structural fill compacted to 90 percent ,
ASTM:D 1557. A higher degree of compaction is not recommended, as this will increase t�
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. This would involve installation of a minimum, 1-foot-wide blanket drain to
within 1 foot of �inish grade for the full wall height using imported, washed gravel against
the walls. A prefabricated drainage mat is not a suitable substitute for the gravel blanket drain
unless all backfill against the wall is free-draining.
12.1 Passive Resistance and Friction Factors
Lateral loads can be resisted by friction between the foundation and the natural glacial 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
Febrcta�y 18, 2010 ASSOC/ATED EARTH SCIENCES, INC.
JP1./Id-KE090�J?6A3-Projec�sl?009DJ361k'L•',W'P Page 19
Subsurf'ace Exploration, Geologic Hazccrds, mzd
Lindbergh High School I�nprovements Preliminary Geotechnical Engineering Report '
Renton, Washington Preliminary Design Reco�nmendntions
least 95 percent of the maximum dry density to achieve the passive resistance provided below.
We recommend the following allowable design parameters:
• Passive equivalent fluid = 250 pcf
• Coefficient of friction = 0.30
13.0 PAVEMENT RECOMMENDATIONS
Pavement areas should be prepared in accordance with the "Site Preparation" section of this
report. If the stripped native soil or existing fill pavement subgrade can be compacted to
95 percent of ASTM:D 1557 and is firm and unyielding, no additional overexcavation is
required. Soft or yielding areas should be overexcavated to provide a suitable subgrade and
backfilled with structural fi1L
The pavement sections included in this r�port section are for driveway and parking areas on-
site, 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. '
The exposed ground should be recompacted to 95 percent of ASTM:D 1557. If required, li
structural fill may then be placed to achieve desired subbase grades. Upon completion of the ',
recompaction and structural fill, a pavement section consisting of 21h inches of asphaltic �,
concrete pavement (ACP) underlain by 4 inches of 1 '/a-inch crushed surfacing base course is '�
the recommended minimum in areas of planned passenger car driving and parking. In heavy ,
traffic areas, such as bus or fire lanes, a minimum pavement section consisting of 3 inches of ��
ACP underlain by 2 inches of 5/a-inch crushed surfacing top course and 4 inches of 1'/a-inch !
crushed surfacing base course is recommended. 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. If an alternate paving system (e.g.,
Grasscrete) is to be considered for the fire loop road, AESI should be contacted ta provide
situation-specific recommendations.
Depending on construction staging and desired performance, the crushed base course material
may be substituted with asphalt treated base (ATB) beneath the final asphalt surfacing. 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 11/z- 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
February 18, 2010 ASSOCIATED EARTH SCIENCES, INC.
IPL!!d-KE090a36.�1.3-Projects',30090�36iKL-IWP Page 20
Subsurfnce Eiploration, Geologic Hnznrds, c�nd �I
Li�idbergli Hig{� Scliool hriprove�rte�:ts Pr•elinaina�y Geotech�rical E�igi►ieeri�:g Report I
Re�lton, Washingto�� Prelimi�iary Design Recommendatio�is
disturbance of the ATB surface should be expected. The general contractor should remove '!
affected areas and replace them with properly compacted ATB prior to final surfacing.
13.1 Porous Asphalt or Permeable Pavernent
We understand that porous pavement is currently under consideration. Recommendations
provided for use in planning and design of porous pavement focus on providing a uniform base
for support of the porous pavement, developing as much storm water storage volume as
possible, and allowing maximum infiltration within the soils beneath the pavement, It our
expectation that the site soils will only provide limited infiltration and that some or all of the
infiltrated storm water will require collection at the downgradient edge of the pavement section
for disposal via conventional storm water methods.
Several of our exploration borings encountered fill that ranged up to 13 feet in depth, while
other borings encountered shallow dense to very dense glacial till. The density of the existing
fill and glacial soils within 18 inches of the existing grass surface is considered to vary widely,
from loose to very dense. In order to provide a uniform base for support of the porous
pavement and to allow maximum infiltration within the soils beneath the pavement, our
recommendations include scarification of the upper 12 inches of soil across the exposed
pavement subgrade.
Following subgrade preparation, we recommend a passenger car pavement section consisting
of a 3-inch compacted porous asphalt paving above a 3-inch thickness of "choker course"
consisting of 5/s-inch crushed surfacing top course. Below the choker course, a 12- to 18-inch-
thick storage layer consisting of 2-inch railroad ballast should be placed above the soil
subgrade. The storage layer should be sized for an appropriate amount of storm water storage
assuming a porosity of 0.30. Since a limited amount of the water will infiltrate the pavement
subgrade during large storm events, a drainage system should be established on the
downgradient side(s) of the permeable pavement. The drainage system should include
perforated pipes connected to the site storm drain system. In areas where buses, garbage
trucks, delivery trucks, or other heavy vehicles will be driven or parked, we recommend a
paving section consisting of 6 inches of porous asphalt, 3 inches of choker course, and
18 inches of storage layer.
Porous asphalt requires regular cleaning t� avoid becoming clogged with silt and contaminants
and to maintain the porous properties. We recommend the District establish a cleaning
schedule as part of the long-term site maintenance.
Febrciary 18, 2010 ASSOCIATED EARTN SCIENCES, lNC.
!PL/!d-KL•0904?6.4 i-ProjcusL'00904?6iK61WP Page 21
Suhsasrface Exploration, Geologic Hazards, and
Lindbergh Hig/i Scliool hnproveme�us Preli�niriary Geotechnical Engineeri�ig Report
Reliton, Washingtoti Preliminary Desigri Recommendations
14.0 PROJECT DESIGN AND CONSTRUCTION MONITORING
Our report is preliminary since project plans were not finalized at the time this report was
written. We recommend that AESI perfarm a geotechnical review of the plans prior to final
design completion. In this way, we can confirm that our earthwork and foundation
recommendations have been properly interpreted and implemented in the design.
We are also available to provide geotechnical engineering and monitoring services during
construction. The integrity of the foundation system 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. Construction monitoring
services are not part of this current scope of work. If these services are desired, please let us
know, and we will prepare a cost proposal.
We have enjoyed working with you on this study and are confident that 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
, ,�p, MERRi
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G.--�`" _'= ✓i.
Jeffrey P. aub, L.G., L.E.G. Kurt D. Merriman, P.F..
Project Engineering Geologist Principal Engineer
Attachments: Figure 1: Vicinity Map i
Figure 2: Site and Exploration Plan
Appendix: Exploration Logs ',
Febrc�a�y 18, 201D ASSOCIATED EARTH SCIENCES, 1NC
JPLiJd-KE090-1_'6�I3-Projeus1;0090-1�6'�KEiWP Page 22
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� � � � � RENTON, WASHINGTON
� PROJ.NO. KE090426A
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APPROXIMATE LOCATION APPROXIMATE LOCATION
OF EXPLORATION BORING OF EXPI.ORATION BORING
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REFERENCE: McGRANAHAN ARCHITECTS
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� Associated Earth Sciences,Inc. SITE AND EXPLORATION PLAN FIGURE 2
� LINDBERGH HiGH SCNOOL DATE 1/10
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� ` ` , � - RENTON, WASHINGTON PROJ.NO. KE090426A
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r h t
_ ' ct N m r Ex loratian Numbe S ee
� ❑ � � � Pro�e u be p
Y-. � '`�`�� KE090426A EB-1 1 of 1
Project Name Lindbefgh High School Ground Surface Elevation(ft)
Location Renton WA Datum N/A i
DrilledEquipmeM BoreteGTrack Rig Date Start/Finish 1913�/Q9 1�/3I1/fl9 I
Hammer Weighf/Drop 140#/30" Hole Diameter(in) R"
o � � o�'i I
� ° �� —� � `� Blows/Foot
�- �
L �
a S E � i. �n' o `m �
0 T � C�rn o m m t I
DESCRIPTION � � 10 20 30 40 � I
Fili - '
Moist,brownish gray,silty fine to medium SAND,with gravel and trace 7
S-� organics. 7 ��a
7
5 Brown and black,silty SAND,with organics over moist, rust-stained Z
S-2 brownish gray,silty fine to medium SAND,with gravel. 2 s
7
-- _- -- - -- _ _ - - - --- -- -- - - - - - - - - - - - -
' Ice-Contact Deposits
S-3 Ma{st,rust-stained brownish gray,SILT,with sand lenses. a �
5 12
7
10 �
S� Gray,clayey SILT for 6"over wet,brownish gray,fine to medium SAND, 6
with siltier zones. s e
9
15 Wet,brownish gray,GRAVEL,with sand and silt. �q
S-5 27 73
----_._.....----------.._---- ------------- ----- 48
Boitom oI exploration boring at 16 5 faet
20
25
30
35
0
0
N
�
�
7
C
A
d
C)
N Sampler Type(ST):
o m 2"OD Split Spoon Sampler(SPTj Q No Recovery M-Moisture Logged by: JPL
o m 3"OD Split Spoon Sampler(D&M) � Ring Sample � Water Level() Approved by:
w � Grab Sample � Shelby Tube Sample 1 Water Level at time of drilling(ATD)
Associated Earth Sciences,lnc. EX loration Lo
� ❑ � � � Project Number Exploration Number Sheet
.�`= � �rts� KE090426A EB-2 1 of 1
Project Name t indberg�High School Ground Surface Elevation(ft)
Location Renton WA Datum �y�a
DrilledEquipment F3orPter.ITrack Rlq. Date Start/Finish 1�13f1/(14,1?/3n/Q�
Hammer WeighVDrop �40#/30'� Hole Diameter(in) �"
c w �
�^ � L� ,O � � N
d -� y BIOWSIFOOt F�
a S E @ i. ��a? o `m
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0 in C9� o co t� �
DESCRIPTION � � to 20 3o ao °
Fill
Moist,brown and gray,silty fine to medium SAND,with gravel and a
S-� organics. �t �23
12
5 Moist,same. a
S-2 5 8
13
�� Moist,brown and black,silry fine to medium SAND,with gravel,organics, �
S-3 and trace woody debris. ao ez
�
- ----- - - - - - - -- - - -
Ice-Contact Deposits
15 �
Wet, bluish gray,fine to medium SAND,with sillier zones,gravel,and trace g
S-4 organics. s t9
t0
Z� Wet,brownish gray,silty fine to medium SAND,with gravel and siltier �p
S-5 zones. 12 �32
-----___ .------ -----..._ _--------------..------ 20
Bottom of exploratfon boring at 21 5 feet
25
30
35
0
b
N
N
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� � 2"OD Split Spoon Sampler(SPT) � No Recovery M-Moisture Logged by: JPL
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w � Grab Sample Q Shelby Tube Sample 1 Water Level at time of drilling(ATD)
Associated Earth Sciences,Inc. EX loration Lo
� ❑ � � � Project Number Exploration Number Sheet
� � ''��� KE090426A EB-3 1 of 1
Project Name Lindbergh High School Ground Surface Elevation(ft)
LocaGon Renton. WA Datum N/A
Driller/Equipment Boretec/Track Rig Oate Start/Finish �l�p/f1q�1�/�p/fl�
Hammer WeighUDrop 140#/30�� Hole Diameter(in) R"
c a� �
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a S E '��° T ��' d � `
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DESCRIPTION � � to 20 3o ao °
Fill
Moist,brown,gray,and black,silty fine to medium SAND,with gravel, q
S-� organics,and woody debris. s �t
s
5 S 2 Moist,same. �2 •
8 t
e
- -- - - - - - _ . - -- - - - -- - - - - - - _ ._. _ -
Ice-Contact Deposits
�� Moist,bluish gray,silty fine to medium SAND,with gravel. g
S-3 12 8
is
15 Moist,blulsh gray,silty fine to medium SAND,with gravel. 2�
S-4 43 50/ '
------ -----------------__ -------------------...__.._ 0/ ��
Bottom of expbration boring at 18 4 feet
20
25
30
35
0
0
N
�
C
N
�
�
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N Sampler Type(ST):
� m 2"OD Split Spoon Sampler(SPT) a No Recovery M-Moisture Logged by: JPL
o m 3"OD Split Spoon Sampler(D 8 M) � Ring Sample SZ. Water Level() Approved by:
W � Grab Sample � Shelby Tube Sample 1 Water Level at time of drilling(ATD)
Associated Earth Sciences, Inc. EX loration Lo
� � � � � Project Number Exploration Number Sheet
�'�`� �' �u°� KE09Q426A EB-4 1 of 1
Project Name Lindbergh High School Ground Surface Elevation(ft)
Location R@ntOn, WA Datum N/A
DrilledEquipment Boretec/Track Rig Date StartlFinish 1�/3�/f1g,1�/�Q/Qq
Hammer WeighUQrop 140#/ 30�� Hole Diameter(in) fi^
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DESCRlPTION U � �0 20 3o ao °
FilUTopsoil
Moist to wet,brown and gray,silty SAND,with gravel,organics,and woody �
S-� debris. 3 �5
2
5 Moist,brown and biack,silty SAND,with gravel,organics,and woody 3
S-2 debris. 3 �5
2
i
S-3 Moist to wet,same. � .
6 '
10
6 i S-4 - - - - .. ._ _- - - - -- - -- -- -- -- --- - - - - - -- - -- 6 � 7
Ice-Contact Deposits ��
Same for 6"over moist to wet, bluish gray,silty fine to medlum SAND,with
gravel.
�g Moist brownish gray,silty fine to medium SAND,with gravel. � �
S-5 __.__.__ _
_...___ . __ _ _ __ _____ sol .�
Bottom of exploration boring at 15 5 feet
20
25
30
35
0
0
a
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m
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N Sampier Type(ST):
� m 2"OD Split Spoon Sampler(SPT) � No Recovery M-Moisfure Logged by: JPL
m m 3"OD Split Spoon Sampler(D&M) � Ring Sample � Water Level() Approved by:
W � Grab Sample � Shelby Tube Sample t water Level at time of drilling(ATD)
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Associated Earth Sciences,Inc. EX loration Lo
0 � ,��x, , Project Number Exploration Number Sheet
0 � � � KE090426A EB-5 1 of 1
Project Name Lindbergh High School Ground Surface Elevation(ft)
Locatian Renton. WA Datum N/A
Driiler/Equipment Boretec/Track Rig Date Start/Finish ��r�nmar1�i3n�Qg
Hamme�Weight/Drop 140#/30�� Hole Diameter(in) 6"
� tn U� ,O > � in
a S E m�, a�a� 3 B�OWS/FOOt �
o T � c��n �o � m s
DESCRIPTION � � �0 20 3o ao °
i - 4 1/2"concrete.
� Vashon Lodgement Till v
- Moist,slightly rust-stained brownish gray,silty fine to medium SAND,with ��
S-1 gravel. 25
58
33
5 Moist,brownish gray,siity fine to medium SAND,with graveL �g
S-2
ao
�s
39
10 24
i -
S-3 Moist,same_ ,
--- - __. __—-----—_--_ _ / sai '
-- -- _ .._ . _ _ _ .
Bottom of exploration boring at 10 9 feet
15
20
25
30
35
0
0
N
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� m 2"OD Split Spoon Sampler(SPT) � No Recovery M-Moisture Logged by: JPL
o m 3"OD Split Spoon Sampler(D 8�M) � Ring Sample � Water Level() Approved by:
w � Grab Sample Q Shelby Tube Sample= Water Level at time of drilling(ATD)
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Associated Earth Sciences,Inc EX (Ot'8t1011 LO '
, Project Number ExploraUon Number Sheet I
`'�`�' 0 �'� � � KE090426A EB-6 1 of 1 '
Project Name �,indbergh High School Graund Surface Elevation(ft) i
�ocation Renton. WA Datum rv�A I
Drlller/Equipment BoreteC/TraCk Rlg Date StarUFinish 1�13f1!(1A�1�/3(l/(19 �
Hammer WeighuDrop 140#!30" Hole Diameter(in) �^ '�
�o .o > � � I
r c, n� y� � � BIOWS/FOOt I� �I
0 T N Ucn �o « m a`> I
DESCRIPTION � � to 20 30 40 �
-2"asphalt. -
_...._. _____.-----._�._---__ --- _._-----._ _ __; ;
Fill(7) --- -- I
Top 4"moist,dark brown,silty SAND,with or�anics and wood�debris_ _ _ 9
S"� Vashon Lodgement Till 24 50 !i
Mpist,slightly rust-stained brownish gray,silty fine to medium SAND,with �
5 gravel.
3_2 Moist,brownish gray,silty fine to medium SAND,with gravel. 38
1 ° sa ��
�� S-3 _ Moist,same. _ � � sa �
Bottom oi exploration boring at 10 5 feet
15
20
25
30
35
0
0
N
�
R
C
R
�
�
a
�
N Sampler Type(ST):
� m 2"OD Split Spaon Sampler(SPT) Q No Recovery M-Moisture Logged by: JPL
o m 3"OD Split Spoon Sampler(0&M) � Ring Sample � Water Level() Approved by:
W � Grab Sample � Shelby Tube Sample t Water Level at time of drilling(ATD)
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Associated Earth Sciences,Inc. EX loration Lo
�y:} � � � { � Project Number Exploration Number Sheet
�'' �9 KE090426A EB-7 1 of 1
Project Name Lindbergh High Schoof Ground Surface Elevation(ft)
Location Renton V1IA Datum N/A
Driller/Equipment Boretec/Track Rig Date Start/Finish 1�13Q/(Lq,����n/ng
Hammer WeighUDrop 140#/ 30'� Hole Diameter{in) �°
C N . �
L a m E �a� 3 BIOWS/FOOt H
p T y �� �o � m �
DESCRIPTION � � �0 20 30 40 �
- 1 1/2"as�halt_- --
--. ._ --- ----- _..._ ___-
Vashon Lodgement Till
Moist,brownish gray,silty fine to medium SAND,with gravel. 38
S-1 23 49
28
5 Moist,same. t8
S-2 3p �o
ao
�p S 3 Mofst,same. �
----- --------___ _ _ - - - ---_ _ - --- i ea �;
Bottom o(exploration boring at 10 5 feet
15
20
25
30
35
0
0
N
N
, �
�
�
'a
�
� Sampler Type(ST):
� m 2'OD Split Spoon Sampler(SPT) � No Recovery M-Moisture Logged by: JPL
o m 3"OD Split Spoon Sampler(D&M) � Ring Sample $� Water Level() Approved by:
w � Grab Sample � Shelby Tube Sample� Water Level at time of drilling(ATD)
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Associated EarEh Sciences,Inc. EX loration Lo
� ❑ � � � Project Number Exploration Number Sheet
r � �`�'h�� KE090426A EB-8 1 af 1
Project Name Llfldbergh High SCflool Ground Surface Elevation(ft)
Location Rent�n WA Datum �!A
DrillerlEquipment Boretec/Track Rig Date Start/Finish 12l3(}lQ9,1,7l�n�n9
Hammer WeighUDrap 140#/30" Hole Diameter(in) ���
c a� �
� N U� O > � N
.c o. �� �Q` � BIOWS/FOOt I�
p T � �N �o � m �
DESGRIPTION � � �0 20 3o ao °
Vashon Lodgement Till
Molst,reddish brown,silty fine to medium SAND,with gravel and trace 3
S-1 organics. a ��
8
5 Moist,slightly rust-stained brownish gray,silty fine to medium SAND,with 17
S'2 gravel. �5 ao
25
�� Moist,same.
_ S-3 17
45 5
---------.—...---_.___ _..__------ – _ __ ____------_ - _ - 50
Bottom of exploration boring at 11 5 feet
�
15 �
20
25
� 30
35
0
0
N
N
�
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W
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$ m 2"OD Split Spoon Sampler(SPT) � No Recovery M-Moisture Logged by: JPL
m � 3"OD Split Spoon Sampler(D&M� � Ring Sample Q Water Level Q Approved by:
W � Grab Sample � Shelby Tube Sample 1 water Level at time of drilling(ATQ)
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Associated Earth Sciences,lnc. EX loration Lo
� � � � � Project Number Exploration Number Sheet
�"�' �` '��= KE090426A EB-9 1 of 1
Project Name Lindbergh� Hiah School Ground Surface Elevation(ft)
Location Renton. WA Datum N!A
DrillerlEquipment Boretec/Track Rig Date StarUFinish 1�/3f1/�A 1�/ 13(L�9_
Hammer Weight/Drop 140#/30" Hole Diameter(in} �
� N =� ,O � � in
°1 BIOWS/FOOf 1�
t o_ �� �a-� 3
o T � (�cn }'E `° � t
DESCRIPTION � � m 10 20 30 40 �
Fill
_ 6"brown,siity SAND,with gravel. _ __ ___ _ __ _ _ __ _ __ _ _ _ a
S"� Vashon Lodgement Till 4 �
Moist,reddish brown,silty fine to medium SAND,with gravel and trace 4
5 arganics.
S 2 Moist,rust-stained brownish gray to brownish gray,silty fine to medium i2
SAND,with gravel. a2 so� ��
o� •
�� g_3 Moist,slightly rust-stained brownish gray,silty fine to medium SAND,with 20„ � „
- graveL -
Bottom of exploration boring at 10 9 feet j
15
20
25
30
35
0
0
N
N
m
�
C
�
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a
�
� Sampler Type(ST):
o m 2"OD Split Spoon Sampler(SPT) Q No Recovery M-Moisture Logged by: JPL
o � 3"OD Split Spoon Sampler(D&M) � Ring Sample Q Water Level() Approved by:
W � Grab Sample � Shelby Tube Sample= Wafer Level at time af drilling(ATD)
Associated Earth Sciences,Inc. EX loration Lo
aa o � � Project Number Exploration Number Sheet ,
�'"-` i� �'� KE090426A EB-10 1 of 1
Project Name Lindbergh High School Ground Surface Elevatlon(ft)
Location Renton WA Datum .�d/A
Driller/Equipment Boretec/Track Rig Date StarUFinish 1230�(19,��/3nm�
Hammer WeighUDrop 140#I 30" Hole Diameter(in} g��
� a� . �
� y V� .O � � in
BIOWSIFOOt H
a S E �° i. ��� o a�
° T �' �N DESCRIPTION � � m t0 20 30 40 �
Fill
Moist,slightly rust-stained brownish gray,silty fine to medlum SAND,with 3
S-1 gravel and trace organics. � �2
1
- - - --- -- -- - -. _ ._— - -- - - - - -- -- - - - - --- - _ _ _
5 Vashon Lodgement Till
S_2 Moist,brownish gray,silty fine to medium SAND,with gravel. 3�
45 50/ �.
0!
No recove �
10 S-3 -----ry:.__ _ _ --- - --..._ __ _ _ —_ --___ . .. - — 5oi ,.
Bottom of exploration boring at 10 3 feet
15
20
25
30
35
0
0
N
N
�
J
C
N
a'
�
N Sampler Type(ST):
o m 2"OD Split Spoon Sampler(SPT) Q No Recovery M-Moisture Logged by: JPL
o � 3"OD Split Spoon Sampler(D&M) � Ring Sample SZ Water Level{) Approved by:
w � Grab Sample � Shelby Tube Sample t Water Level at time of drilling(ATD)
a
Associated Earth Sciences,Inc. EX loration Lo
� � � � � Project Number Exploration Number Sheet
� � '`�r� KE090426A EB-11 1 of 1
Project Name Lindbergh High School Ground Su�face Elevation(ft)
LocaGon Renton. WA Datum N�q
Driller/Equipment Borete�/Track Rig Date Start/Finish ����nmg�1�l��/�9
Hammer WeighUDrop 140#I 30" Hole Diameter(in) R"
c m �
� N V- O > = y
L Q, o,a �� � � BIOWS/FOOt �
O T tn �� �� 10 00 L
DESCRIPTION " � �0 20 3o ao °
Fill
S � Moist,brown,silty SAND,with gravel and organics. q -
a
3
5 S 2 Moist,same. 4 -
4
- - - - - - - - -- - - Vashon Lodgement Till - - _ _ ._._ - -- _- - -
3
S-3 Moist to wet,slightly rust-stained,silty fine to medium SANO,with gravel. t t
20 63
43
�� Moist to wet,same �5
S-4 �g 5q
----------------— - - - _ 36
Bottom of expbration boring a111 5 feet
15
20 ,
25
3Q
35
0
o '
N
N
T
N
J
N
�
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�
N Sampler Type(ST):
� m 2"OD Split Spoon Sampler(SPT) Q No Recovery M-Moisture Logged by: JPL
o � 3'OD Spllt Spoon Sampler(D 8 M) � Ring Sample � Water Level() Approved by:
W � Grab Sample � Shelby Tube Sample t Water Level at time of drilling(ATD)
Associated Earth Sciences,Inc. EX loration Lo
�. � Project Number Exploration Number Sheet
��"�' � �`+��� � � KE090426A EB-12 1 of 1
Project Name Lindbergh Hlqh School _ Ground Surface Elevation(ft)
Location Renton. WA Datum �y/A
Driller/Equipment 6oretec/Track Rig Date Start/Finish ���3��Q9,��/3[L/(L9
Hammer Weight/Drop 140#/30'� Hole Diameter(in) �^
c a> „N
� � L � � � � BIOWS/FOAt I°-�
� —y � �n
a S E � � ��:: o o�
o T `�' ��' U � 0° S
DESCRIPTION �0 20 3o ao
Fil l
Mast,brown,fine to medium SAND,wilh gravel. g
S'� 10 19
- - - - - - - - - _ .__ ._ _. . -- - - - 8
Ice-Contact Deposits
5 Moist,brown,GRAVEL,with sand.
S-2 5
19 53
�
-- --- - - - -- - - ----- - - -- - -
� Vashon Lodgement Till
�� Moist to wet,slighUy rust-stained brownish gray,silty fine to medium �q
S-3 SAND,with gravel. ta 29
15
15 Mofst,same.
S-4 �
38 81
-----___ ____---_---__._.—_ ___ ----------------- 43
Bottom of exploration boring at 16 5 feet
20
25
30
35
0
0
N
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�
7
C
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a.
�
� Sampler Type{ST):
� � 2"OD Split Spoon Sampler(SPT) � No Recovery M-Moisture Lo99ed by: JPL
o m 3"OD Split Spoon Sampler(D&M) � Ring Sample �. Water Level O Approved by:
W e Grab Sample Q Shelby Tube Sample t Water Level al time of driliing(ATD)
c
Associated Earth Sciences, Inc. EX loration Lo
� � � � � Project Number Exploration Number Sheet
KE02763A EB-lA 1 of 1
Project Name Lindbergh Hiqh School � Ground Surface Elevation(ft)
Lor,ati�n Renton. WA Datum N/A
DriiledEquipment Davies/Track Rig Date StarUFinish �vn�rn��1/�/fl�
Hammer Weight/Drop 140#/ 30" Hole Diameter(in)
� � L n � � io y
� a n �,� � � Blows/F�ot �
a S E ��. �n � o =
� T y � ym
DESCRIPTION � � �0 2o so ao °
Ftll q
S-� Moist,dark brown with red staining,sandy SILT to silry SAND with 3 �5
organics,wood,gravel,and charwood. (ML) z
Moist,gray,sitty,fine SAND,little gravel. (SM) i
S-2 g 20
12
5 Till
S-3 Moist,gray,mottled,silty,fine SAND with gravel. (SM) te � �
�s
1� az
S-a o so� -
Bottom of exploration boring at t t feet
No ground water
15
20
25
30
35
0
N
�
j
C
N
�
�
a
�
� Sampler Type(ST):
o m 2"OD Split Spoon Sampler(SPT) � No Recovery M-Moisture Logged by: SGB
o � 3"OD Split Spoon Sampler(D&M) � Ring Sample � Water Level() Approved by:
w � Grab Sample � Shelhy Tube Sample 1 Water Level at time of drilling(ATD)
VII. OTHER PERMITS
This project will obtain and NPDES permit and a development permit from the City of Renton,at a minimum,
prior to construction.
, COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
21 Renton,Washington
VII1. CSWPPP ANALYSIS AND DESIGN
Standard Requirements
Erosion/Sedimentation Plan shall include the following.
1. Facilities required include:stabilized construction entrance,sedimentation pond,interceptor swales, filter
fobric fencing. (1.2.5-1). The project will provide a stabilized construction entrance,filter fabric fencing,a
sediment storage vault,and interceptor swales.
�
2. Timing-For the period between November 1 through March 1 disturbed areas greater than 5,000 square
feet le ft undisturbed for more than 12 hours must 6e covered with mulch,sodding, or Qlastic covering. A
construdion phasing plan shall6e¢rovided to ensure that erosion control measures are installed prior to
clearing and gmding.(1.2.5-1). Notes addressing each of these items have been placed on the civil engineering
plans.
3. Planning-Plan shall limit tributary drainage to an area to be cleared and graded. Delineate dimension,
stake and flag clearing limits(1.2.5-1). The clearing limiu have been indicated on the TESC plan. Notes
addressing this item have been placed on the civil engineering plans.
4. Revegetatron-Revegetate areas to be cleored os soon as practicable after grading. (1.2.5-1). Notes
addressing this item have been placed on the civil engineering plans.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
22 Renton,Washington
IX. BOND QUANTITY, FACILITY SUMMARIES,AND DECLARATION OF
COVENANT
The Renton School District is a public agency and is therefore not required to post a bond for this development
Facilities Summary Sheet is included in this section.
Declaration of Covenant will be submitted separately.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
23 Renton,Washington
X. OPERATION AND MAINTENANCE MANUAL
Standard Maintenance
Per standards set forch in the King Counq Surface Water Design Manual,the owner will maintain facilities. Sections
of the King County Storm Water Management Design Manual outlining the Operations and Maintenance of these
facilities have been included in this section on the following pages.
__�
i
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
24 Renton,Washington
MAINTENANCE STANDARDS FOR
PRIVATELY MAINTAINED DRAINAGE
FACILITIES AT LINDBERGH HIGH SCHOOL
NO. I - RAIN GARDENS
Maintenance Defect Conditions When Maintenance Resuks Expected When
Component Is Needed Maintenance Is Performed
General Trash& Any trash and debris which exceed I cubic Trash and debris cleared
Debris foot per I,000 square feet(this is about from site.
equal to the amount of trash it would uke
to fill up one sundard size office garbage
can). In general,there should be no visual
evidence of dumping.
Poisonous Any poisonous or nuisance vegetation No danger of poisonous
Vegetation which may constitute a hazard to Counq vegetation where County
personnel or the public. personnel or the public
might normally be.
(Coordination with Seatde-
King County Health
Department)
Pollution Oil,gasoline,or other contaminanu of one No contaminants present
gallon or more or any amount found that other than a surface film.
could: I)cause damage to plant,animal,or (Coordination with
marine life;2)constitute a fire hazard;or Seattle/King County Health
3) be flushed downstream during rain Department)
storms.
Unmowed if facility is located in private residential When mowing is needed,
Grass/ area,mowing is needed when grass grass/ground cover should
Ground exceeds 18 inches in height In other areas, be mowed to 2 inches in
Cover the general policy is to make the pond site height Mowing of selected
match adjacent ground cover and terrain as higher use areas rather than
long as there is no interference with the the entire slope may be
function of the facility. accepuble for some
situations.
Rodent Any evidence of rodent holes if facility is Rodenu destroyed and dam
Holes acting as a dam or berm,or any evidence of or berm repaired.
water piping through dam or berm via (Coordination with
rodent holes. Seattle/King County Health
Department)
Insecu When insects such as wasps and horneu Insects destroyed or
interfere with maintenance activities. removed from site.
Tree Growth Tree growth does not allow maintenance Trees do not hinder
access or interferes with maintenance maintenance activities.
activity(i.e.,slope mowing,silt removal, Selectively cultivate trees
vactoring,or equipment movemenu). If such as alders for firewood.
trees are not interfering with access,leave
trees alone.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
25 Renton,Washingcon
Side Slopes of Erosion Eroded damage over 2 inches deep where Slopes should be stabilized
facility cause of damage is still present or where by using appropriate erosion
there is potential for continued erosion. control measure(s);e.g., rock
reinforcement, planting of
_ grass,compaction.
Storage Area Sediment Accumulated sediment that exceeds 10%of Sediment cleaned out to
, the designed pond depth. designed pond shape and
depth;pond reseeded if
necessary to control erosion.
Emergency Rock Missing Only one layer of rock exisu above native Replace rocks to design
Overflow/Spillw soil in area five square feet or larger,or any standards.
ay exposure of native soil at the top of out
flow path of spillway. Rip-rap on inside
slopes need not be replaced.
Note: Sediment accumulation of more than.25 inches�er year may indicate excessive erosion is occurring upstream of the
facility or that conveyance systems are not being properly maintained. The contributing drainage area should be checked for
erosion problems or inadequate maintenance o('conveyance systems i�excessrve sedimentation is noted in an infihration faality.
Check twice a year during firrt 2 years of operation;once a year thereafter. Gean manholes/catch basins,repair damaged
inleu/ourlets,clean trash racks.
NO. 2- CLOSED DETENTION SYSTEMS(VAULTS)
Maintenance Defect Conditions When Maintenance is Results Expected When
Component Needed Maintenance is
Performed
Storage Area Plugged Air One-half of the cross section of a vent is Venu free of debris and
Venu blocked at any point with debris and sediment
sediment
Debris and Accumulated sediment depth exceeds 10% All sediment and debris
Sediment of che diameter of the storage area for% removed from storage
length of storage vault or any point depth area.
exceeds 15°6 of diameter. 6cample:72-inch
storage tank would require cleaning when
sediment reaches depth of 7 inches for
more than %2 length of tank.
Manhole Cover Not in Cover is missing or only partially in place. Manhole is closed.
Place Any open manhole requires maintenance.
Locking Mechanism cannot be opened by one Mechanism opens with
Mechanism Not maintenance person with proper tools. Bolu proper tools.
Working into frame have less than % inch of thread
(may not apply to self-locking lids.)
Cover Difficult One maintenance person cannot remove lid Cover can be removed and
to Remove after applying 801bs of lifc Intent is to keep reinsulled by one
cover from sealing off access to maintenance person.
maintenance.
Ladder Rungs King County Safeq Office and/or Ladder meets design
Unsafe maintenance person judges that ladder is standards allows
unsafe due to missing rungs,misalignment, maintenance person safe
rust,or cracks. access. '
COUGHLINPORTERLUNDEEN Lindber h Hi h School Im rovements II
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26 Renton,Washingcon
Cacch Basins See"Catch Basins"Standards No.4 See"Catch Basins"
$tandards No.4
NO. 3 - CONTROL STRUCTURE/FLOW RESTRICTOR
Maintenance Defect Condition When Maintenance is Results Expected
Component Needed When Maintenance is
Performed
General Trash and Disunce between debris build-up and All trash and debris
Debris(Includes bottom of orifice plate is less than I-I/2 feet. removed.
Sediment)
Structural Structure is not securely attached to manhole Structure securely
Damage wall and outlet pipe structure should support attached to wall and oudet
at least I,000 Ibs of up or down pressure. pipe.
Structure is not in upright position (allow up Structure in correct
to 10%from plumb). position.
Connections to outlet pipe are not Connections to outlet
watertight and show signs of rust pipe are water tight;
structure repaired or
replaced and works as
designed.
Any holes--other than designed holes—in the Structure has no holes
structure. other than designed holes.
Cleanout Gate Damaged or Cleanout gate is not watertight or is missing. Gate is watertight and
Missing works as designed.
Gate cannot be moved up and down by one Gate moves up and down
maintenance person. easily and is watertight
Chain leading to gate is missing or damaged. Chain is in place and
works as designed.
Gate is rusted over 50%of iu surface area. Gate is repaired or
replaced to meet design
sundards.
Orifice Plate Damaged or Control device is not working properly due Plate is in place and works
Missing to missing,out of place,or bent orifice plate. as designed.
Obstructions Any trash,debris,sediment,or vegetation Plate is free of all
blocking the plate. obstructions and works as
designed.
OverFlow Pipe Obstructions Any trash or debris blocking(or having the Pipe is free of all
potential of blocking)the overflow pipe. obstructions and works as
designed
Manhole See"Closed Detention Systems"Standards See "Closed Decencio�
N� 2 Svsr� .. .
Catch Basin See"Catch Basins"Standards No.4 See'Catch Basins"
Standards No.4
NO.4-CATCH BASINS
Maintenance Defect Conditions When Maintenance is Results Expected
Component Needed When Maintenance is
performed
General Trash&Debris Trash or debris of more than I/2 cubic foot No Trash or debris
(Includes which is located immediately in front of the located immediately in
Sediment) catch basin opening or is blocking capacity of front of catch basin
che basin by more chan 10% opening.
Trash or debris(in the basin)that exceeds No trash or debris in the
I/3 the depth from the bottom of basin to catch basin.
invert the lowest pipe into or out of the
basin.
Trash or debris in any inlet or outlet pipe Inlet and oudet pipes free
blocking more than I/3 of its height. of trash or debris.
Dead animals or vegetation that could No dead animals or
generate odors that could cause complainu vegetation present within
or dangerous gases(e.g., methane). the catch basin.
Deposiu of garbage exceeding I cubic foot in No condition present
volume which would attract or
support the breeding of
insects or rodenu.
Structure Corner of frame extends more than 3/4 inch Frame is even with curb.
Damage to past curb face into the street(If applicable).
Frame and/or
Top Slab
Top slab has holes larger than 2 square inches Top slab is free of holes
or cracks wider than I!4 inch (intent is to and cracks.
make sure all material is running into basin).
Frame not sitting flush on top slab,i.e., Frame is sitting flush on
separation of more than 3/4 inch of the frame top slab.
from the top slab.
Cracks in Basin Cracks wider than I/2 inch and longer than Basin replaced or repaired
Walls/ Bottom 3 feet,any evidence of soil particles to design sundards.
entering catch basin through cracks,or
maintenance person judges that structure is
unsound.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
28 Renton,Washington I
Cracks wider than I/2 inch and longer than No cracks more than I/4
I foot at the joint of any inleU outlet pipe inch wide at the joint of
or any evidence of soil particles entering inledoutlet pipe.
catch basin through cracks.
Sedimend Basin has settled more than I inch or has Basin replaced or repaired
Misalignment rotated more than 2 inches out of to design standards.
alignment
Fire Hazard Presence of chemicals such as natural gas, No flammable chemicals
oil and gasoline. presen�
Vegeution Vegetation growing across and blocking No vegetation blocking
more than 10%of the basin opening. opening to basin.
Vegetation growing in inledoudet pipe No vegetation or root
joinu that is more than six inches tall and growth present
less than six inches apart.
Pollution Nonflammable chemicals of more than 1/2 No pollution present
cubic foot per three feet of basin length. other than surface film.
Catch Basin Cover Not in Cover is missing or only partially in place. Catch basin cover is
Cover Place Any open catch basin requires maintenance. closed
Locking Mechanism cannot be opened by on Mechanism opens with
Mechanism Not maintenance person with proper tools. proper tools.
Working Bolu into frame have less than I/2 inch of
thread.
Cover Difficuk One maintenance person cannot remove Cover can be removed by
to Remove lid after applying 80 Ibs.of lift;intent is keep one maintenance person.
cover from sealing off access to
maintenance.
Ladder Ladder Rungs Ladder is unsafe due to missing rungs, Ladder meets design
Unsafe misalignment,rust,cracks,or sharp edges. standards and allows
maintenance person safe
access.
Meul Grates Grate with opening wider than 7/8 inch. Grate opening meets
(If Applicable) design standards.
Trash and Trash and debris that is blocking more than Grate free of trash and
Debris 20%of grate surface. debris.
Damaged or Grate missing or broken member(s) of the Grate is in place and
Missing. grate. meeu design standards.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
29 Renton,Washington
NO. 5 DEBRIS BARRIERS(E.G.,TRASH RACKS)
Maintenance Defect Condition When Maintenance is Results Expected
Components Needed When Maintenance is
Performed.
General Trash and Trash or debris that is plugging more than Barrier clear to receive
Debris 20%of the openings in the barrier. capacity flow.
Metal Damaged/ Bars are bent out of shape more than 3 Bars in place with no
Missing Bars. inches. bends more than 3/4 inch.
Bars are missing or entire barrier missing. Bars in place according to
design.
' Bars are loose and rust is causing 50% Repair or replace barrier
deterioration to any part of barrier. to design standards.
NO. 6 - ENERGY DISSIPATERS
Maintenance Defect Conditions When Maintenance is Results Expected
Components Needed When Maintenance is
Performed.
Manhole/ Worn or Structure dissipating flow deteriorates to Replace structure to
Chamber Damaged Post. I/2 or original size or any concentrated design standards.
- Baffles,Side of worn spot exceeding one square foot
' Chamber which would make structure unsound.
Other Defects See"Catch Basins"Standard No.4 See"Catch Basins"
Standard No.4
NO. 7 - FENCING
Maintenance Defect Conditions When Maintenance is Results Expected
Gomponents Needed When Maintenance is
Performed
General Missing or Any defect in the fence that permiu easy Parts in place to provide
Broken Parts entry to a facility. adequate security.
Erosion Erosion more than 4 inches high and 12- No opening under the
I 8 inches wide permitting an opening fence that exceeds 4
under a fence. inches in height
, Wire Fences Damaged Parts Post out of plumb more than 6 inches. Post plumb to within I-I/2
inches.
Top rails bent more than 6 inches. Top rail free of bends
- greater than I inch.
Any part of fence(including post,top Fence is aligned and meeu
rails) more than I foot out of design design standards.
alignment
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
30 Renton,Washington
��ISSiIi��. i:;J � �t�'S;�'� JvI��C. i E:Ii�l�il��� �h����E �.. . . ...
holding fabric
Extension arm missing,broken,or bent 6ctension arm in .
out of shape more than I I/2 inches. with no bends lar
3/4 inch.
Deteriorated Part or paru that have a rusting or scaling Structurally adeq�
Paint or condition that has affected structural posts or parts w
Protective adequacy. uniform r
Coating
NO. 8 - GATES
Maintenance Defect Conditions When Maintenance is Results Expected
Component Needed When Maintenance is
Performed
General Damaged or Missing gate or locking devices. Gates and Locking devices
Missing in place.
Members
Broken or missing hinges such that gate Hinges intact and lubed.
cannot be easily opened and closed by a Gate is working freely.
maintenance person.
Gate is out of plumb more than 6 inches Gate is aligned and
and more than I foot out of design vertical.
alignment,
Missing stretcher bar,stretcher bands, Stretcher bar,bands and
and ties. ties in place.
Openings in See"Fencing"Standard No.7 See"Fencing"Standard
Fabric No.7
NO. 9-CONVEYANCE SYSTEMS(PIPES& DITCHES)
Maintenance Defect Conditions When Maintenance is Results Expected
Component Needed When Maintenance is
Performed
Pipes Sediment& Accumulated sediment that exceeds 20% Pipe cleaned of all
Debris of the diameter of the pipe. sediment and debris.
Vegetation Vegetation that reduces free movement All vegetation removed so
of water through pipes. water flows freely through
pipes.
Damaged Protective coating is damaged; rust is Pipe repaired or replaced.
causing more than 50%deterioration to
any part of pipe.
Any dent that decreases the cross section Pipe repaired or replaced.
area of pipe by more than 20�/.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
3 I Renton,Wazhington
Catch Basins See "Catch Basins: Standard No.4 See "Catch Basins"
Standard No.4
Debris Barriers See"Debris Barriers"Standard No.S See"Debris Barriers"
(e.g.,Trash Sundard No. 5
Rack)
NO. 10 - GROUNDS(LANDSCAPING)
Maintenance Defect Conditions When Maintenance is Results Expected When
Component Needed Maintenance is
Performed
General Weeds Weeds growing in more than 20�of the Weeds present in less than
(Nonpoisonous) landscaped area(trees and shrubs only). 59�of the landscaped area.
Safety Haurd Any presence of poison ivy or other No poisonous vegetation
poisonous vegetation. present in landscaped area.
Trash or Litter Paper,cans,bottles,totaling more than I Area clear of litter.
cubic foot within a landscaped area(trees
and shrubs oniy)of I,000 square feet
Trees and Damaged Limbs or parts of trees or shrubs that are Trees and shrubs with less
Shrubs split or broken which affect more than than 5%of total foliage
25%of the total foliage of the tree or with split or broken limbs.
shrub.
Trees or shrubs that have been blown Tree or shrub in place free
down or knocked over. of injury.
Trees or shrubs which are not adequately Tree or shrub in place and
supported or are leaning over,causing adequately supported;
exposure of the roou. remove any dead or
diseased trees.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvements
32 Renton,Washington
NO. I I -ACCESS ROADS/EASEMENTS
Maintenance Defect Condition When Maintenance is Results Expected When
Component Needed Maintenance is
Performed
General Trash and Debris Trash and debris exceeds I cubic foot per Roadway free of debris
I,000 square feet i.e.,trash and debris which could damage tires.
would fill up one sundards size garbage
can.
Blocked Debris which could damage vehicle tires Roadway free of debris
Roadway (glass or metal). which could damage tires.
Any obstruction which reduces clearance Roadway overhead clear to
above road surface to less than 14 feet 14 feet high.
Any obstruction restricting the access to a Obstruction removed to
I 0 to I 2 foot width for a distance of more allow at least a I 2 foot
than I 2 feet or any point restricting access access.
to less than a I 0 foot width.
Road Surface Settlement, When any surface defect exceeds 6 inches Road surface uniformly
Potholes, Mush in depth and 6 square feet in area. In smooth with no evidence of
Spou, Ruts general,any surface defect which hinders settlement,potholes,mush
or prevents maintenance access. spou,or ruts.
Vegetation in Weeds growing in the road surface that are Road surface free of weeds
Road Surface more than 6 inches tall and less than 6 taller than 2 inches.
inches tall and less than 6 inches apan
within a 400-square foot area.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenu
33 Renton,Washingcon
NO. I 2-WATER QUALITY FACILITIES
A.)Cartridge Filter Vault
Maintenance Defect or Condition When Maintenance is Recommended
Component Problem Needed Maintenance to
Correct Problem
Below Ground Sediment Sediment depch exceeds 0.25-inches. No sediment deposiu
Vault Accumulation which would impede
on Media. permeability of the
compost media
Sediment Sediment depth exceeds 6-inches in first No sediment deposiu in
Accumuladon chamber. vault bottom of first
in Vault chamber.
Trash/Debris Trash and debris accumulated on compost Trash and debris removed
Accumulation filter bed. from the compost filter
bed.
Sediment in When drain pipes,clean-ouu,become full Remove the accumulated
Drain with sediment and/or debris. material from the facilities.
Pipes/Clean- �
Outs I
Damaged Any part of the pipes that are crushed, Pipe repaired and/or
Pipes damaged due to corrosion and/or replaced.
settlement.
Access Cover Cover cannot be opened,one person Cover repaired to proper
Damaged/ cannot open the cover,corrosion/ working specifications or
Not Working deformation of cover. replaced.
Vault Cracks wider than 1/2-inch and any Vault replaced or repaired
Struaure evidence of soil par�icles entering the to design specifications.
Includes structure through the cracks,or
Cracks in maintenance/inspection personnel
Wall, Bottom, determines that the vault is not
Damage to structurally sound.
Frame and/or
Top Slab
Cracks wider than 1/2-inch at the joint of No cracks more than I/4-
any inledoudet pipe or any evidence of soil inch wide at the joint of
particles entering the vault through the the inlet/outlet pipe.
walls.
Access Ladder Ladder is corroded or deteriorated,not Ladder replaced or
Damaged functioning properly,missing rungs,cracks, repaired and meeu
and misali���-' specifications,and is safe to
use as determined by
inspection personnel.
COUGHLINPORTERLUNDEEN Lindbergh High School Improvemenr�
34 Ren�on,Washingtnn