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ENGINEERING REPORT
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4`� �� �� �� Technical Inform�tion Report
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�4� Renton High School Renovation and
� � �' Performing Arts Center
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Project No. C990030-03
- March 16,2000 !�
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PREPARED FOR:
Renton School District#403
1220 N 4�'Street
Renton,WA 98055
Contact:Jack Connell �� ����� }���`��`���.'
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PREPARED THROUGH: ��_£� ����� ; '��� >
Nort{2west Architectural Compan} : �� ��_ � ,�, � "
2201 Sixth Avenue ��� }������
Suite 1405
Seattle,WA 98121
�� C p Contact:Guy Overman
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� ''� t� PREPARED BY:
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�otsghlin Porter La�ndeen
.o ��,�h57� v Q,4 217 Pine Street,Suite 300 � �"
�O'�'�ss�1`T��,�' � Seattle,Washington 98101;�` `` ' . , � ,E � ;�
fONAL� Z� t, Phone: (206)343-04b0 �=� ����
` 1�;� '�v � �� :
ExPz�es o��z3izcoz Contact:Mr.Steve Po er,PI�AR 2 0 2000 f'
�UILDING DIVt6iON
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��UGHLIN PORTERLUNDEEN
Page 1 of 2
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
- . . . - . . .
. . . .
Project Ovmer Renton School District#403 Project Name Renton Hiqh School Renovation and Performina
Arts Center
Address 1220 N 4th Street Renton.WA 98055
Location 400 S 2nd Street Renton.WA 98055
Phone (425)204-4475
Project Engineer Steve Porter.P.E. Township �
Company Couahlin Porter Lundeen.Inc. �nge �E
Address Phone 217 Pine Street Sufte 300 Seattle WA 98101 Section 1�
j2061 343-0460 Project Size 25•60 AC
Upstream Drainage Basin Size 0 AC
, � . . � . �
❑ Subdivision ❑ DOF/G HPA ❑ Shoreline Management
❑ Short Subdivision ❑ COE 404 ❑ Rockery
❑ Grading ❑ DOE Dam Safety ❑ Structural Vaulfs
� Commercial ❑ FEMA Floodplain ❑ Other(NPDES)
❑ Other ❑ COE Wetlands ❑ HPA
• � � •
Communiry Basin '
Lower Cedar River Drainaae Basin
� - .
❑ River ❑ Floodplain
❑ Stream ❑ WeUands
❑ Critical Stream Reach ❑ Seeps/Springs
❑ Depressions/Swales ❑ High Groundwater Table
❑ Lake ❑ Groundwater Recharge
❑ Steep Slopes ❑ Other
❑ Lakeside/Erosion Hazard
. �
Soil Type Slopes Erosion Potential Erosive Velocities
an 0.5%to 2.0%
❑ Additional Sheets Attached
1/90
Page 2 of 2
King County Building and Land Development Division
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
� � � - �
REFERENCE LIMITATION/SITE CONSTRAINT
❑
❑
❑
❑
❑
❑
❑ Additional Sheets Attached
. ,
MINIMUM ESC REG�UIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION FOLLOWING CONSTRUCTION '
� Sedimentation Facilities � Stabilize E�osed Surface
� Stabilized Construction Entrance � Remove and Restore Temporary ESC Facilities
� Perimeter Runoff Control � Clean and Remove All Sitt and Debris
❑ Clearing and Grading Restrictions � Ensure Operation of Permanent Facilities
� Cover Practices ❑ Flag Limits of NGPES
� Construction Sequence ❑ Other I
❑ Other
� �
❑ Grass Lined Channel ❑ Tank ❑ Infiltration Method of Analysis
� Pipe System ❑ Vault ❑ Depression SBUH usina Tvoe 1 A rainfall
Compensation/Mitigation of
❑ Open Channel ❑ Energy Dissipater ❑ Flow Dispersal Eliminated Site Storage
❑ Dry Pond ❑ WeUand ❑ Waiver
❑ Wet Pond ❑ SUeam ❑ Regfonal Detention
Brief Description of System Operations On-site surface runoff is collected and conveyed through a catch basin and oioe svstem to the
existing site discharae�oint.
Facility Releted Sfte Limitations ❑ Additional Sheets Attached
Reference Facility Limitation
,
. .
❑ Cast in Place Vault ❑ Other ❑ Drainage Easement
❑ Access EasemeM
❑ Reteining Wall
❑ Native Growth Protection Easement
❑ Rodcery>4'High � Tract
❑ Structural on Steep Slope ❑ Other
• • • ' • •
I or a civil engineer under my supervision have visited the site. Actual site conditions as ;��-,
observed were incorporated into this worksheet and the attachments. To the best of my L-Cj��-. �, .� !ic`tC:.::r
knowledge the information provided here is accurate. sr0�ee�a�e
1/90
Technical Information Report
Renton High School Renovation and Performing Arts Center
Table of Contents
PROJECTOVERVIEW....................................................................................................................2
EXISTING DRAINAGE AND SITE CONDITIONS....................................................................2
PROPOSEDDRAINAGE SYSTEM................................................................................................3
DOWNSTREAM ANALYSIS...........................................................................................................3
SITEHYDROLOGY.........................................................................................................................3
Co�REQumEMErrrs.............................:..........................................................................................................................3
SPECIAI.REQUIREMEN'I'S....................................................................................................................................................4
DE'I'EIV'I'ION ANALYSIS........................................................................................................................................................6 '
WATERQUALTI'Y ANALYSiS...............................................................................................................................................7
CONVEYANCEANALYSIS....................................................................................................................................................7
TEMPaRARY EROSION AND SEDA4ENT CON'IROL•••..........................................................................................................S
APPENDICES
APPENDIX A Figures
APPENDIX B Stormwater Calculations
APPENDIX C Operations and Maintenance Manual
COUGHLIN PORT'ER LiTNDEEN 1 Renton H.S. Renovation
Technical Information Report �,
Renton High School Renovadon and Perfoxming Arts Center '
Coughlin Porter Lundeen Project No.C990030-03 ,
March 16,2Q00
PROJECT OVERVIEW
Renton High School is located at 400 South 2nd Street in Renton,Washington (see ,
Figure 1 -Site Vicinity Map in Appendix A). The project site lies adjacent to the
Renton Central Business District and is bounded to the north by South Tobin �
Street,to the south by South 2nd Street, to the east by Logan Avenue South,and to
the west by Lake Avenue South. The campus is currently composed of three large
buildings,student/faculty parking areas,paved tennis courts, and grass fields.
The proposed project includes demolition of the east wing of the existing school
and construction of a new Performing Arts Center in its place. Project
improvements will consist of major interior renovation of the existing school,
gymnasium, and industrial arts buildings,construction of new parking lots and
tennis courts,and installation of new utilities.
The project construction and new utility installation will be phased from june 2000
to September 2002 to allow for continuous operation of the school. Most of the
earthwork for new pavements is expected to occur in the last phases from
February to September 2000.
The project will provide stormwater runoff control and water quality treatrnent ,
per the 1990 King County Surface Water Drainage Manual (KCSWDM}. Surface ',
water runoff kom new parking areas,roadways,and walkways will be collected ''
by catch basins and area drains and discharged to the public storm system in South �
Tobin Street in accordance with City of Renton Engineering Standards. '
Supporting calculations and documentation are included with this report in ,
Appendix B. '
EXISTING DRAINAGE AND SITE CONDITIONS
The project site is approximately 25.60 acres and currently developed with the ,
existing Renton High School and associated parking lots and athletic fields (see
Figure 2—Existing Site Conditions in Appendix A). The project site lies within the
Lower Cedar River sub-basin of the Cedar River Drainage Basin,but discharges to
the Black River sub-basin of the Green River Drainage Basin. The site is relatively
flat and gently slopes hom east to west. �'I
Site runoff is currently split into two drainage sub-basins,with approximately 90 �,I
percent flowing to the north sub-basin and 10 percent flowing to the south. The ,
north sub-basin drainage is collected in catch basins and piped from east to west �
COUGHLIN PORTER LUNDEEN 2 Renton H.S.Renovation
where it discharges to the public storm systems in South Tobin Street and Lake
Avenue South. The south sub-basin drainage sheet flows to the south and ,
discharges to the public storm system in South 2nd Street.
PROPOSED DRAINAGE SYSTEM '
The proposed project will add a new performing arts center in place of the existing
east wing of Renton High School. The existing tennis courts will be relocated and
existing parking lots will be reconfigured (see Figure 3—Proposed Site Conditions
in Appendix A).
The proposed drainage system for the project site will collect runoff from new
roofs and paved areas. Surface runoff from new parking areas,drives,and
walkways will be collected by catch basins and area drains. Surface runoff
generated hom the rooftop of the proposed performing arts center will be collected
via roof drains. The downspouts and footing drains will be tight-lined to the
proposed conveyance system. The proposed conveyance system will consist of
typical catch basin and dosed pipe systems and will discharge to the public storm
system in South Tobin Street.
DOWNSTREAM ANALYSIS
There are no upstream tributary areas to the project site. The majority of the runoff
from the project site discharges to the public storm system in either South Tobin
Street or Lake Avenue South. A smaller portion of site runoff discharges to the
public storm system in South 2nd Street. The storm systems in Lake Avenue South
and South 2�Street flow in a southwesterly direction where they converge
approximately 0.64 miles downstream of the site near the intersection of Hardie
Avenue Southwest and the Burlington Northern Railroad. Runoff eventually
discharges to the Black River approximately 1.3 miles downstream of the project
site.
SITE HYDROLOGY
Core Req,uirements
This section will address the requirements set forth by the Core Requirements �'
listed in Chapter 1 of the 1990 King County Surface Water Design Manual �I
(KCSWDM). �
1. Dischar e at the Natural Location (1.2.1)—The develo d storm runoff will be collected, II
S �
mnveyed,and discharged at the natural discharge location
�I
i
COUGHLIN PORTER LUNDEEN 3 Renton H.S.Renovation ''�
2. Off-Site Anulysis(1.2.2)-The off�ite analysis is discussed in the"Downstream
Analysis"section of this report.
3. Rurwf�'Control(1.2.3)—
A. Peak Rate Runoff Control: Detention will not be required for this project due
to a negligible increase in the peak runoff rate for the 100-year,24-hour '
storm event. According to the "Exemptions From On-Site Peak Rate Runoff
Control"section of the KCSWDM,the site is exempt from runoff contxol
because the increase in the peak runoff rate for the 100-yr/24-hr storm event
is less than 0.5 cfs. Further discussion of this subject is covered in the
"Detention Analysis"section of this report.
B. Biofiltration: Since developed conditions will not produce more than 5,000
SF of new impervious area subject to vehicular use,the project is not subject
to this requirement. This project will actually decrease the amount of
impervious area subject to vehicular use by approximately 7,480 SF.
Further discussion of this subject is covered in the "Water Quality Analysis" ,
section of this report. '
4. Conveyance Fc�cilities(1.2.4)-This subject is covered in the"Conveyance Analysis"
section of this report.
5. Erosion/Sedimentatian Control Plan(1.2.5)-This project will install a series of temporary
erosion and sediment control BMP's(Best Management Prackices)related to specific
conditions on site. Tlvs subject will be covered in the"Temporary Erosion and
Sediment Control"seckion of this report.
6. Muintenance and Operation(1.2.6)—The proposed on-site storm drainage system will
be owned,operated,and manitained by the owner.
7. Bonds and Liability(1.2.7)—The owner and contractor will obtain all necessary pernuts
prior to the beginning of mnstruction. School districts are not subject to bonding. '
Special Requirements
This section will address the requirements set forth by the Special Requirements
listed in Chapter 1 of the 1990 King County Surface Water Design Manual
(KCSWDM).
COUGHLIN PORTER LUNDEEN 4 Renton H.S. Renovation
1. Critical Drainage Areas(1.3.1)—The project site is not located in a Cxitical Drainage '
Area.
2 Compliance urith an Existing Master Drainage Plan(1.3.2)—The project site is not located
within an Existing Master Drainage Plan.
3. Conditions Requiring a Master Drainage Plan(1.3.3)-The praject does not require a
Master Drainage Plan.
4. Adopted Basin or Community Plans(1.3.4)—The praject site is located in the Lower
Cedar River subbasin of the Cedar River Drainage Basin. However,the project site
discharges to the Black River subbasin of the Green River Drainage Basin Currently,
the site is not subject to any community plans.
5. Special Water Quality Controls(1.3.5)—The proposed development decreases the
amount of impervious area subject to vehicular traffic by 7,480 SF. Therefore,the
development is not subject to this requirement.
6. Caalescing Plate Oil/Water Separators(1.3.6)—The proposed development decreases the
amount of impervious area subject to vehicular traffic by 7,480 SF. Therefore,a ,
coalescing plate oil/water separator is not required.
7. Closed Depressians(1.3J)—There are no closed depressions on or downstream of the
project development. Therefore,the project is not subject to this requirement.
8. Llse of Lakes, Wetlnnds ar Closed Depressions for Peak Rate Rurcof�'Control(1.3.8)—The
project will not use lakes,wet]ands,or closed depressions for peak rate runoff mntrol.
9. Delineation of 10QYaar Floadplain(1.3.9)-The project is not located within a designated
100-YR Iloodplain.
10. Flood Protectiorc Facilities for Class 1 and 2 Streams(1.3.10)-There are no streams and
existing or proposed Ilood protection facilities within the project site.
11. Geotechnical Analysis and Report(1.3.11)-The project does not propose to use a pond
or infiltration system,or to modify exisiing flood protection facilities. Therefore,a
geotechnical analysis and report addressing the effects of groundwater interception
and infiltration is not required.
12. Soil Analysis and Report(1.3.12)—Soils in the area have been mapped as indicated by
the Soil Conservation Service,1973 King County Soils Report. A geotechnical
COUGHLIN PORTER LUNDEEN 5 Renton H.S. Renovation
engineering report for the project site was prepared by Associated Earth Scsences in
Apri11999.
Detention AnalXsis
The drainage system for the project site was designed in accordance with the 1990
King County Surface Water Design Manual (KCSWD1Vn. The peak flows for the
associated hydraulic design were determined using the Santa Barbara Urban
Hydrograph(SBUI� Method with Type lA rainfall distribution. The hydrologic
computer program Waterzvorks Version 4.09 was used to develop design
hydrographs (stormwater calculations are induded in Appendix B).
Impervious and pervious surface areas were determined for both the existing and
proposed site conditions as shown in the following table.
Drainage Basin Areas Tab1e
Area Existin Conditions Pro osed Conditions
Im ervious Area ac 11.32 acres 12.21
Pervious Area ac 14.28 acres 13.39
Total Area ac 25.60 25.60
Peak flow rates for the 100-yr/24-hr design storm were determined for both the
existing and proposed site conditions as shown in the following table.
Peak Flow Rates Table
Peak Flow Rate Existin Conditions Pro osed Conditions
100- /24-hr storm cfs 17.42 cfs 17.67 cfs
The increase in peak runoff rate for the 100-yr/24-hr design storm for proposed
developed conditions was only 0.25 cfs.
In accordance with the "Exemptions From On-Site Peak Rate Runoff Control"
section of the KCSWDM,detention will not be required for this project due to a
negligible increase in peak runoff rate for the 100-year,24hour storm event. The
increase in the peak runoff rate for the 100-yr/24-hr storm event is less than 0.5 cfs.
COUGHLIN PORTER LUNDEEN 6 Renton H.S. Renovation
;
6�ti'ater_Qualit��nalvsi5 �I
Imper��-ious surtace areas subject to�-ehiclzlar use �ti�ere determined for both the �I
existing and proposed site conditions as shown in the following table. I
Impervious Areas Subject to Vehicular Use Table �I
Existin Conditions Pro osed Conditions '
Vehicular Area s 271,868 sf 264,384 sf '
The proposed development decreases the amount of impervious area subject to '
vehicular use by approximately 7,480 SF. Therefore,the project is not required to ',
provide runoff water quality treatment. ,
Convevance Analvsis
The conveyance system was designed to convey peak flows from the 25-year 24-
hour storm event using the rational method. The conveyance system is divided
into two separate systexns,routing runoff north and south around the existing
school building. The systems were designed to convey stormwater runoff at a
velocity of at least 3 ft/sec at full capacity using Manning's equation. Conveyance
calculations are included in Appendix B.
T'he northern conveyance system collects runoff for approximately 6 acres of
impervious surfaces including a portion of the performing arts center roof, student
parking lot,bus loop,courtyard, tennis courts, and north parking lots. Stormwater
runoff sheet flows across the ground surfaces to catch basins and roof drains are
tight-lined directly to the storm system. The storm system is composed of new 8-
inch, l2-inch,and 18-inch pipes and type I and II catch basins. The conveyance
system starts in the student parking lot,flows west through the courtyard and
heads north to pick up runoff from the north parking lots and tennis courts. The
north conveyance system discharges to the public storm system in South Tobin
Street.
The southern conveyance system collects runoff for approximately 1.2 acres of
impervious surfaces including a portion of the performing arts center roof and the
visitor and west parking lots. Stormwater runoff sheet flows across the ground
surfaces to catch basins and roof drains are tight-lined directly to the storm system.
The storm system is composed of new 8-inch and 12-inch pipes and type I catch
basins. The conveyance system starts in the visitor parking lot and flows to the
west parking lots. The south conveyance system discharges to an existing onsite
structure which flows west across the existing athletic fields and eventually
discharges to the public storm system in either South Tobin Street or Lake Avenue
South.
COUGHLIN PORTER LUNDEEN 7 Renton H.S. Renovation
Temporary Erosion and Sediment Contr+
To m;nimi�e the amount of sediment laden w�:.�_ ._�__._�:.: __.
a ---_ �_._ ___-----� �
construction process,a temporary erosion and sedimentation control(TESC)plar-
been designed for this project in accordance with KCSWDM. The TESC plan indicai
m;n;r„um necessaxy measures that the contractor shall implement during the construction
process. Best Management Practices(BMP's) are defined as physical,structural and/or
managerial practices that,when used in combination,prevent or reduce pollution of water
caused by construction activities. The TESC plan for the proposed project has been
designed to protect off-site properties as well as m;n;m;�e the quantity of sediment-laden
water from entering the public storm system. 7'he follo�ving BMP's ha�-e been included on
the TESC plan for this project:
To ensure that the disturbance of the site is lunited to the development area, the clearing
limits will be clearly staked prior to any clearing or grading as shown on the T'ESC plan.
Stabilized construction entrances/wheel cleaning stations will be provided at the points of
egress and ingress to the development area. The stabilized construction entrance shall
reduce the amount of sedixnent transported onto paved roads by motor vehicles.
Catch basin protection will be used on existing and future catch basins to reduce
sediment-laden water from entering the existing storm system during consiruction.
Cover measures such as mulch,seeding,or plastic sheeting will be implemented for
disturbed areas greater than 5,000 square feet in accordance with the City of Renton
Standards.
All construction debris will be promptly removed from the site to rrLn;mi�e demolition
and construction impacts on the site. The contractor shall implement additional BNIl''s as
required and/or recommended by the City of Renton inspector or other agencies as
required to prevent demolition and construction debris,waste material,fuel,oil,
lubricants,and other fluids hom entering the public storm system.
Renton H.S. Renovati n I�
COUGHLIN PORTER LUNDEEN 8 0
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RENTON HIGH SCHOOL
100 YEAR PEAK RUNOFF RATES ANALYSIS
---------------------------------------------------------------------
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BASIN SUMMARY
BASIN ID: 100YRDV NAME: 100-YR DEVELOPED CONDITIONS
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 25 . 60 Acres BASEFLOWS : 0 . 00 cfs �
RAINFALL TYPE. . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 3 . 85 inches AREA. . : 13 . 39 Acres 12 .21 Acres
TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00
TC. . . . : 15 . 00 min 15 . 00 min
ABSTRACTION COEFF: 0 .20
TcReach - Sheet L: 210 .00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0100
TcReach - Channel L: 293 . 00 kc :42 . 00 s : 0 . 0140
TcReach - Channel L: 165 .00 kc :42 . 00 s : 0 . 0050
PEAK R.ATE : 17 . 67 cfs VOL: 6 . 37 Ac-ft TIME: 480 min
BASIN ID: 100YREX NAME: 100-YR EXISTING CONDITIONS
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 25 . 60 Acres BASEFLOWS : 0 . 00 cfs
R.AINFALL TYPE. . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 3 . 85 inches AREA. . : 14 . 28 Acres 11 .32 Acres
TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00
TC. . . . : 15 . 00 min 15 . 00 min
ABSTR.ACTION COEFF: 0 .20
TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0080
TcReach - Shallow L: 140 . 00 ks : 11 . 00 s : 0 . 0070 �
TcReach - Channel L: 293 . 00 kc :42 . 00 s : 0 . 0140
TcReach - Channel L: 165 . 00 kc :42 . 00 s : 0 . 0050
PEAK RATE: 17 .42 cfs VOL: 6 .28 Ac-ft TIME: 480 min
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Runoff from Triangular Lot and Bus Loop
CONVEYANCE SYSTF,M ANALYSIS AND SIZING TAI3LE USING THE RATIONAL IvfETHOD
Location Sub Area C C*A Sum Tc i(lt) I(R) Q(R) Pi e T . Slo e Q(P) V V I. '1't ���d/D
Basin (ac) C*A (min.) (c.f.s.) (in.) n (ft.ft.) � ( i e (�i e {at (ft.) (n�in.)
From To Number full) full) Q(R))
CB 15 CB 14 15 0.15 090 0.13 0.13 G.3 0.80 2.73 0.37 8 0.014 0.011 120 3.44 2.91 145.0 0,$ 39.OU`%
CB 14A CB 14 14A 0.11 090 0.10 0.10 6.3 0.80 2.73 027 8 0.014 0.019 1.55 4.44 3.39 76.0 0.4 28A0°Ir�
CB 14 CB 13 14 0.42 0.90 p.38 0.C2 7.1 0.74 2.52 1.55 12 0.014 0.006 2.63 3.35 3.43 9G.0 O.S SGAO�I�
CB 13B CB 13A 13B 0.29 0.90 0.26 0.26 6.3 0.80 2.73 0.72 8 0.014 OA10 t.13 3.24 3.41 137.0 0.7 Sb.50�7�
CB 13A CB 13 13A 0.35 090 0.31 U.58 7.0 0.75 2.Sfi L48 12 0.014 0.007 ?.85 3.63 3.62 I 10.0 0.5 51.50�/0
CB 13 CB 12 13 0.14 090 0.13 1.32 7.6 OJ 1 2.42 3.]9 12 0.014 0.010 3.32 423 4.85 8-1.0 03 78.00°l0
CB 12C CB 12B 12C 0.17 0.90 O.a S Q.15 63 O,KO ?.73 O.�.l 8 OA14 0.010 l.13 3.24 2.92 h L0 0.5 42.UQ�%�
CB 12B CB 12A 12B 0.16 0.90 0.14 0.29 6.8 0.77 2.G1 U.77 8 0.014 OA10 1.13 3.24 3.47 100.0 0.5 60.50°l>
CB 12E CB 12D 12E 0.16 090 0.14 0.14 6.3 O.SO 2.73 0.38 8 0.014 0.010 1.13 3.24 2.90 �i9.O U.� 40.SO�lo !
CB 12D CB 12A 12D 0.13 0.90 0.12 0.2G 6.8 0.7G 2.G0 O.fi7 8 0.014 0.010 1.13 324 �.31 76.0 0.4 56.00%�
CB 12A CB 12 12A 0.17 0.90 0.16 0.71 7.2 0.73 2.50 � 1.7G 12 0.014 OA10 3.32 4.23 4.28 l0O_0 Q.4 52.00%
CB 12 CB 11 12 0.40 0.90 0.36 2.38 7.9 0.70 2.36 5.63 18 0.014 0.005 6.92 392 4.40 12b.0 0.5 6b.00���
CB 11A CB 11 11A 028 0.90 0.25 0.25 6.3 0.80 2.73 0.(i9 8 0.014 0.010 1.13 3.24 3.35 13.0 0.1 57.00���
CB 11F CB 11E 11F 0.12 090 0.11 0.11 6.3 0.8Q 2.73 0.3O 8 0.014 0.010 I.13 324 2.6G 27.0 0.2 3(i.�0�70
CB 11E CB 11D 11E 0.02 0.90 0.02 0.13 6S 0.79 ?.G9 O.3S 8 0.014 0.039 2.23 G,39 4.79 30.0 0.1 26.0O���
CB 11D CB 11C 11D 0.02 090 0.02 0.15 6.6 � 0.78 2.66 � � 0.39 8 0.014 0.015 '� l.3$ 3.95 3.39 31.0 0.2 36.5O°/n
CB 11C CB 11B 11C OA2 0.90 0.02 0.17 6.7 0.77 2.62 0.44 8 0.014 0.017 1.48 424 3.G1 2�.0 0.1 38.00�I�-
CB 11B CB 11 11B 0.09 09U 0.0� 0.25 6.8 U.76 Z.Sy 0.G5 8 0.014 0.015 138 3.95 3.81 96.0 0.4 49.00%
CB 11 CB 10 11 0.00 0.00 0.00 2.8) 8.4 0.67 2.27 6.56 18 0.014 0.005 G.92 3.92 4.47 I 1-1.0 O.4 77.50�%
Project: Renton H.S.Modernization R= 25 yr P(FZ)= 3_a0 Calcs by: DTM Job N��: C990030-03
Location: Renton,Washington Date: 3/14/00 Page 1 of 1
Runoff from North Parking Lots and Tennis Courts
CONVEYANCE SYSTEM ANALYSIS ANI) SI7.iNG TABLE USING TI�RATIONAL MF.THnD
Location Sub Area C C*A Sum Tc i(R) 1(R) Q(K) Pi e T . Slo e Q(F) V V L 'I't %d/D
Basin (ac) C*A (min.) (c.t'.s.) (in.) n (ftft.) �( i e � ( i e {at (ft.) (min.)
From To Number full) full) Q(Rj)
CB 2D CB 2C 2D 0.09 0.90 0.08 0,08 63 0.80 2.73 0.23; 8 0.014 0.0]0 1.13 3.24 2.60 195.0 l.3 30.00�/�
CB 2C CB 2B 2C 0.25 0.90 0.22 b.31 7.6 0.71 2.43 0.�-�' 12 0.014 0.006 2.4fi 3,l 3 2.73 114.0 0.7 38.UU%�
CB 2F CB 2B 2F 0.10 0.90 0.09 O.Oy 6.3 0.80 2.73 024 8 OA14 0.010 I:1,3 324 2.G0 62.0 0.4 31.00°Io
CB 2B CB 2A 2B 0.12 0.90 0.I 1 0.50 8.2 O.li7 2.29 �L(G 12 OA14 0.010 � � �3.32 � 4.23 3.81 77.0 0.3 �41.00%0
CB 2E CB 2A 2E 030 0.9U 0,27 0.27 6.3 0.8O 2.73 0.73 8 0.014 0.013 1:29 3.70 3.76 76.0 0.3 54:SO�o
CB 2A CB 2 2A 021 0.90 0.19 0.96 8.G 0.66 2.24 2.I G 12 0.014 OA 10 3.32 4.23 4.47 94.0 0.4 59.00%0
CB 25 CB 24 25 0.23 090 0.20 020 6.3 0.80 2.73 Q.SC 8 0.014 OA10 1.13 3.24 3.20 62.0 0:3 50.0t)'I�
CB 24 CB 23 24 0.15 0.90 0.13 0.34 6.6 0.78 2_65 O.�U 8 0.014 OA10 1..13 3.24 ;3.G4 77.0 0.4 (i6.50°Io
CB23 EXCB 23 0.16 0.90 0.14 0.48 7.0 O.75 2.56 1.24 12 0.014 OA10 3.32 �23 3.8�) 67.0 C).3 42.SOnln
Project: Renton H.S.Modernization fz= 25 yr P(lt)= 3.4U Calcs by: ll'1'M Jc�h Nc,: C990030-03
Location: Renton,Washington Date: 3/14/00 Page 1 of 1
Discharge to S. Tobin St. for North Lots, Courtyard, Bus Loop, and Triangular Lot
CONVEYANCF.SYSTF.M ANALYSiS ANI)ST7,ING TABI.F.USING THE RATI(�NAL MF,'I'1lOf)
Location Sub Area C C:�A Surz7 Tc i(It) I(.R) Q(R) Pi e T . Slop� Q(Ii) V V C. T`t �I d/D
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CB lOB CB l0A lOB 0.01 090 0.01 0.41 63 0.8� 2.73 0.02 8 0.014 0.010 1.13 3.?4 2.10 d5.0 0.4 7.00�'/<�
CB l0A CB l0 l0A 0.02 090 Q.02 0.03 6.7 0.78 2.(i4 0.08 8 0.014 0.010 1.13 3.24 1.94 7fi.O 0.7 17.00�70
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CB 10 CB 9 10 0.08 0.90 0.07 3.18 8.x 0.65 ?.20 693 18 0.014 O.00b 7.25 4;1� 4."7? (,�.(1 (.L2 78:00°>>
CB 9E CB 9D 9E 0.05 090 �.04 p.04 6.3 (�.80 2.73 0.12 8 0.014 0.010 1.13 3.24 2A8 35.O 0:3 22,00�%�
CB 9D CB 9C 9D 0.03 090 0,03 0.07 6.(i 0.78 2.G5 0.20 8 0.014 0.010 1.13 3.24 2.47 -33.0 0,3 28.00�'/c�
CB 9C CB 9B 9C 0.05 090 p.0� 0.12 6.9 0.7C 2.58 0.30 8 0.014 0.010 I.13 �3.24 2.74 58.0 0.4 35.�0�%,
CB 9B CB 9 9B 0.04 0.90 O.Q4 � 0.15 7.2 0.73 2.50 O.38 8 0.014 0.01O 1.13 3.24 2.$G 49.0 Q.3 �4p.5Q'7o
CB 9A CB 9 9A 0.04 090 0.0� 0.0-� 63 0.80 2.73 0.10 8 0.014 0.027 �� 1.84 � � 5�.27 �3.23 �f;.0 0.2 14.00'I�
CB 9 CB 8 9 0.08 0.)0 Q.07 3.43 9.0 0.64 2,.16 7.42 18 0.014 OA06 7.53 4.29 4.93 70.0 0.2 79.50{Io
CB 8 CB 7 8 0.08 090 Q.07 3S( 9.3 0.62 3.12 7.�6 18 0.014 OAO(i 7:Sh 4?y 4.95 56.0 t).2 79.50°/r:�
CB 7A CB 7 7A 0.04 0.9O O.q3 0.O3 63 0.8O ��2:73 b.0�) 8 0.014 0.0111 1�.13 �� 3.24 � 1.�6 2�.0 0.2 19.00�/�
CB 7B CB 7 7B 0.01 0.90 p.01 0.0( 6.3 0.80 2.73 O.04 8 0.014 0.014 I.3 I 3.75 2.�2 I I.0 0.( l O.QO�%�
CB 7 CB 6 7 0.00 0.00 U.(10 3.Sb 9S 0,62 2.10 7.46 18 0.014 0.006 7:58 4.29 4.95 44.0 0.] '74,50%
CB 6 CB 5 6 0.00 0.00 p.�0 3.56 9.6 (3.61 2.08 738 18 0.014 0.006 7.53 4?9 �.93 105.0 0.4 79.Q0�1,
CB 5 CB 4 5 0.28 090 0.2fi 3.81 10.0 `0:60 2.U3 7.'73 l8 0.014 0.007 7.89 4.�16 5.13 95.0 0.3 79.50�1�
CB 4 CB 3 4 015 0.90 0.1=1 �� 3.<)5 10.3 �0.55 � l.�)�a 7.b5 18 0.014 0.007 � �� ��8A1 4.53 ��5,�1� 62.0 '''Q.w ���7y�5k)�7�
CB 3 CB 2 3 0.15 090 0.14 4,Q8 10.5 p.5g j.96 R.O1 18 0.014 0.0(17 8.07 4._57 5,2') 6').0 U.2 80.00"/�
CB 2A CB 2 2A 0.21 0.90 0.19 0.9fi 8.(i U.66 2.?4 2.16 12 0.014 0.010 3.32 4.23 4.47 ')4.0 O,q 5�),00�'I<�
CB 2 C$ 1 2 0.22 0.9U � O.'lO S.0_5 10.7 �� O.57 L')4 9,78 18 0.014 0.010 � 9.93 � 5.62 G.�49 63.0 02 �7�.SO�I�
CB lA CB 1 lA 0.08 090 � 0.07 � (1.U7 6.3 � � 0.80 2.73 � 0.20 8 0.014 0.010 � 1.13 ����3.24 � 2.4(i h8.0 Q.G ' 25:00���
B 1 EX CB 1 0.07 0.90 0.06 5.l 8 10.9 O.S6 I.92 9.94 ]8 0. 14 0.01 R 12.9�i 7'32 b.i 0 5.0 0.0 65._50�%�
Project: Renton . . o ernization R=25 yr P(R)= 3.40 Calcs by: U'I'M Job No: C990030-03
Location: Renton,Washington Date: 3/14/00 Page 1 of ]
Runoff from Visitor Parking Area and West Parking Lot �
CONVEYANCF,SYSTEM ANALYSIS AND SIZING TABLr LJSING THE RATIONAI,METHOD
Location Sub Area C C*A Sum Tc i(R) I(R) Q(R) Pi e T . Slo e Q(F) V V L Tt °lo d!D
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CB 22 CB 21 22 0.25 090 023 023 6.3 U.�iO 2.73 O.G2 8 0.014 0.009 1.07 3A7 3.16 60.0 0.3 55.00°�0
CB 21 CB 20 21 0.20 090 0.18 0.40 6.6 O.�S 2.65 1.U7 8 0.014 0.010 1.13 3.24 3.fi9 85.0 U.4 77:50%�
CB 20 CB 19 20 0.06 0.90 0.05 0.4G 7A b.'15 2.55 L l7 12 0.014 0.005 235 299 2.94 175.0 1.0 SO,50°I<,
CB 19 CB 18 19 0.03 090 0.03 0.49 8A 0.G9 2.34 1.15 12 0.014 0.005 2.35 2.99 2.92 148.0 0.8 50.(��I�
CB 18 CB 17 18 0.30 0.90 027 U_76 8.8 O.GS 2.19 LC7 12 0.014 O.00S 2.35 2.99 3.27 155.0 0.$ G2.�O�1:
CB 17 CB 16 17 026 0.90 0.23 1.00 9.6 p.61 2.08 2.07 12 0.014 0.005 235 299 3.39 K7.0 0.4 72.SO�l�
CB 16 EX CB 16 0.08 0.90 0.07 1.07 10.] 0.59 2.02 2.16 12 0.014 0.005 2.35 2.99 3.39 184.0 0.9 75.50���,
EX CB - EX CB 0.00 0.00 OAO 0.91 11.0 O.SG 1.�1 1.74 12 0.014 0.005 235 2.99 `.�.2? 0.0 G�.00�/0
II
Project: Renton H.S.Modernization R= 25 yr P(R)= 3.40 Calcs by: 'I)'fM Job No: C990030-03
Location: Renton,Washington Date: 3/14/00 Page 1 of 1
COUGHLINPORTERLVNDEEN
A CONSULTING SfRUCTURAL AND CML ENGINEERING CORPORATION
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217 Pine Street • Suite 300 • Seattle, WA • Phone (206) 343-0460 • Fax (206) 343-5691 I'
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King County SAO Drainage Basin Map
217 Pine Street • Suite 300 • Seattle, WA • Phone (206) 343-0460 • Fax (206) 343-5691
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ACONSULTING STRUCTURALAND CML ENGINEERING CORPORATION '
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SCS Soils Map
217 Pine Street • Suite 300 • Seattle, WA • Phone (206) 343-0460 • Fax (206) 343-5691
5. DEPARTN�ENT OF AGRICULTURE � '���'
.. .r..
�IL CONSERVATION SERY►CE ' '-•'� "
KING COUNTY qR
�w _
-�:�:�
- , �<�:L°�:-�
SOIL LEGEND � �
i f.t�int ccD�+ol lar.r.is+M in:+fol one o(+he so�l ne'+e. A second coPiiol lar+er, .
A, 9, C,D,E,o P, tnd�cau�+!�e cicis of siope. :y-�bols w��hwt o siope lener �
ore thos�of n�o.ly lewl soila.
SYMBOL NAN.E
Bou.+ea
AZg Llcerwood Qrc��liy san2y Ix�n, G+e:,ercene sloaes '�6��
�4C A�oe•�ood proveily sondy loom, 6:0 15 pacem siopea . �o��
qp�7 L�da.,00C srov�lly�ondy locm, 1�+0 3:�rcem alap�s -
AKF Alder..00d ond Ki+iap soils,v�ry s+ee� C��11
L.m3 Aren�r,Aide'wcod rra+eriol,0�o C cerc�^.•�icpss• .
Arn� Areny,Aloe�ood rn�+e.�ol,6+0 15 perc��+�lo;es• I�ce�
� An Arer.is,=verett me�eriol• —
, •r.�
oeC 6�ovst+e prowlly sendy loom,6+0 19 xrcenr slepes 5•�+07
cep 3eovsi+e q•ewlly sency�oom, 15+o SC vercent slopes
� 3cF �ec.,s��.i-e.•t:�,o..�r'w ,—.. ...�....�.��,....�.. Len�
5F� :�Il�nsharr.tih�oom Ta.�s
�r �ri�cof f�it Ixn
B� Euc4ley aih loe�n
��:
Cb Coes+ol:eac�es -ec�;c
Ea Ea�mont silt loom �ec•�c
Ed Edsew:ck fiMf�OnCY�OOT 7�,,,,;
E�3 E�er��t y�o�etly so�dy loen,O Te�percenr slooes
��C Ever�»�.ovelly fendy looin,S to 15 Dercenr ticaes ��"�
E�p E�r•sn s�o��t;y�en2y Ixm, 15+e?C.ercen�slexs �-c•
EwC E���en•:.Idery.00d��e�elly son2y Ixns,6�0 1$percem slo�s
:ovni
Ir.A InC�o�o�o Ioe-Y 1�ne aend,O+e=xroe'�sloxs
InC Ind�onoio Ixmy f�ne se�d,-�0 19:e•:e^�s�oGes U^.��,�
� Inp In2�onok ioorr fine aer�, i5�0 3Q pe�c�m stepes ,
I Kp3 K�+sep s�h loom,2+o E oe.cem�1e�s - �. _. ..
KpC K�+aeD s�l�foem, E+e 15 cerc�nr slepes
K�D Knsop s�lf Ixm, 1:+o?D pe•cem slepes Sc^o
j KsC Kio�s gro.�elly Ixny so:d,6+0 1:pe.een�slopes
�'Ji.i
Mo Mi>ed a�lwial lond
Fc+.
NeC Neil+on very pre��lty Ioo-Y�o'.o,��c:`,;krcem a lopes . t
•.
NQ Kewbert silt :x'e .
� !Jk NooG�eck�ilt loem �'•�"
�o �'arw�on2y Ioem
�o-
a o-«.��
Lx
cY a,a,o,�� ���
OvC C�all trawlty loom,O+o IS p�+c�n��kpes
O•D Ovoit prcvetly Iaon, !:io 45�.cen��foD�s
pvF Oroll yrowlly lam,tC+o 75 percenr�lopes �y
Pc piith�ck Ioolny{irw sond
Pk P�Ichuc4 fin�sondy loom (
Pu Pus�+tiiry cley Ixrn
Fy P�yeiluD f�ne sondy loam �"
RoC Ro9nor lirx sonc�y Ixm,6+0 15 perc�r.r�lopes
Ro'J Rog�wr fin�sondy loe�*, 15�0 25 percent slopes ':c
Fd� Rez*o..Indtene�eeasx�cT�w,�loDins•
RdE Rosner.lnc�onolo essec��i7on,mo��re��e'y sfeep• .
Rr 'nemon silt loem
R1� Fiverweah � -
c-
So Satol tih!xm .
Sh Sommo�•.cih s�h loom �
$k $eCr.i�mut� '
$n $tiCleot muc4
$n �i aih Ix,n .�
Se S�o!+omish�ih loom
9 S�ehomish��M lop�n,thiC4 i�rfoce vc•�rn � �
SJ ��ItO'1�IN IOOT �
7u -..•���o�uek '
Lk ll�bon 1en� �
' N'o M'oodln.ille fllt locm
• 7M compes�tion o(�ties�uni�t �� rea� �o.lob���hon+Ao� ot+tit otFr.s
In+he m�o.b�n ���+cs been con�rolled..ell�novyh�o�me�p�N fa+M
e.prc�ed us�o�iM so�i�.
KING COtiNTY, �VASH11` GTO :�I, SURFACE �'�' ATER DESIGN T•ZANUAL
f�.� {2) CN values can be area weighted when they appiy to pervious areas of similar CN's (within 20
. : CN points). However, high CN areas should not be combined with low CN areas {unless the
� .�� ;���' low,CN areas are less than 15% of the subbasin). In this case, separate hydrographs shou{d be
generated and summed to form one hydrograph.
FIGURE 3.5�A HYDROLOGIC SOIL GROUP OF THE SOILS IN KIT�'G COUIr'TY
FiYDROLOGIC FiYDROLOGIC '
SO1L GROU? GROUP' SO1L GROUP GROUP• '
Alderwood C Orczs Peat D ,
Aren2s, fJderwood t�fateri�l C Oridia D '
Rrer,:s, Everett Material 8 OvaA C '
8eausi,e C F�7chuck C
BeUingham D Pugef D
Briscot D � Puyallup B
Buc4.�fey D P.agrar B
Coasial Seaches Varia�e Renton D
Earlmont Sili loam D Riverwash Variable
Edgewick C Salaf C
�verett A I3 `S2mmamish D
Indiano'a A Se2nle D
Kitsap C Sh2car D
baus C Si Silt C
Mixed Atlwial land Varuble Snohomish D
Neilton � A Sultan ', C
Newberg B ua '� D
. Nooksack C U ban � Var� e
� ' Normal Sandy. Loam D Woodinville
HYDr�OLOGIC SOII GROUP CI.�SSIFICATIOtvS u,�p ffyp��y�r
Sot�.. G-ieouP �G'
. 1�.1 AtJR+�51S
A (Low runoY potentia�. Sols F�2ving high infiliration r2ies, even w;�en thoroughly we;ted, and consisiing
chieny of deep,welf-to-excessively drained sands or gravels. These soiis have a high rate o!water
transrnission.
B. (Mode:ately low runoff poten:�al). So1s tuving moderaie inf�tration rates vrt,en thoroughly wetted, and
consis:ing chieSy of moderately Tine to moderately coarse textures. These sols have a moderate rte of
water transmission.
C. (Moderately high runo�f pote�;sa�. Sa�s having slow Enfli tration rates when thoroughly wetie�, and
cons�sting chieRy ot sols wi;h a layer that i�npedes downward movement of water, or so�7s wi:h moderzie!y
fine to fine textures. These so�,s have a slow rate of water transmission. .
D. (High runott poteniia�. So1s Fszving very slow intltration rates when thoroughly we�ted and consisting
chie�y o{clay sols wi:h a high swetling po;eni'�al, so�s with a permanent high wate�table. soils with a
hardpan or clay(ayer ai or near the sur�ace,and shaUow soits over nearfy imperv�ous material. These soits
have a very slow ra,e of K�a;er transmission.
• From SCS,TR-55, Second Edition,June i936, Exhiblt A-1. Revisions made irom SCS, So�1 lnierpretation
. . � Record, Form #5,Se�tember t988. ��
� 3.5.2-2 lIl92
KING COUNTY, 1�VASHINGTON, SURFACE VJATER DESIGN MANUAL
TABLE 3.S:ZB SCS �i'ESTERN�i'ASI�INGTON RUNOFF CURVE NUTv(BERS
SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982}
Runo�f curve numbers for selected agricultural, suburban and urban land use for Type �A
rainfall distribution, 24-hour storm duration.
' CURVE NUMBERS BY
HYDROLOGIC SOIL GROUP
LAND USE DESCRIPTION A B C D �
Cultivated land(1): winter condition 86 91 94 95
Mountain open areas: • tow growing brush and grasslands 74 82 89 92
Meadow or pasture: 65 78 BS 89
Wood or(orest land: undisturbed or older second growth 42 64 76 81
Wood or forest land: young second growth or brush 55 72 8t 86
Orchard: with cover crop 81 88 92 94
Open spaces, lawns, parks, gol(courses, cemeteries,
landscaping.
good condition: gress cover on 75°,6
or more of the area 68 80 � 90
fair condition: grass cover on 50°k
to 75°�6 ot the area 77 85 90 92
Gravel roads and parking lots 76 85 89� 91
Dirt roads and parking lots 72 82 87 8g r
Impervious surfaces, pavement, roots, etc. 98 98 98
Open water bodies: lakes, wetlands, ponds, etc. 100 100 t00
Single Family Aesidential (2) '
Dwelling Unit/Gross Acre °.6 Impervious (3)
t.4 DU/GA t5 Separate curve number
1.5 DU/GA 20 shall be selected
2.0 DU/GA 25 tor pervious and
2.5 DU/GA 30 impervious portion
. 3.0 DU/GA 34 of the site or basin
3.5 DU/GA 38
4.0 DU/GA 42
4.5 DU/GA 46
5.0 DU/GA 48
5.5 DU/GA 50
6.0 DU/GA 52 .
6.5 DU/GA �4
7.0 DU/GA 56
Planned unit developments, % IT�7QNIOUS _
condominiums, apartments, must be computed
commercial business and
industr'�al areas. �
,
(�) For a more detai►ed description ot agricultural land use curve numbers reter to National Engineering
Handbook, Section 4, Hydrology, Chapter 9, Augus2 1972.
(2) Assumes roof and driveway runoif is directed into street/siorm system.
(3) 7he remaining pervious areas (lawn) are considered to be in good condition for these curve numbers.
r
� 3.5.?-3 , il/9?
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN T4ANUAL
o Catch basin (or manhole? diameter shali be determined by pipe orientation at the junction
structure. A plan view of the junction structure, drawn to scale, wil{ be required when
more than four pipes enter the structure on the same plane, or if angles of approach and
clearance between pipes is of concern. The plan view (and sections if necessary) must
ensure a minimum distance (of solid concrete wall} between pipe openings of 8" for 48"
and 54" catch basin's and 12" for 72" and 96".
Evaluation of the structural integrity for H-20 loading may be required for multiple
junction catch basins and other structures.
o Catch basins shall be provided within 50 feet of the entrance to a pipe system to provide
for silt and debris removal.
o HDPP pipe systems longer than 100 feet must be secured at the upstream end and the
downstream end placed in a 4' section of the next larger pipe size. This sliding sleeve
connection allows for the high thermal expansion/contraction coefficient of this pipe
materiaL
o The maximum slope of the ground surface for a radius of 5' around a catch basin grate or
solid lid shall be 3:1.
TABLE 4.3.4A PIPE SlZES AND LENGTHS BETWEEN STRUCTURES
Upstream Structure to Pipe Diameter Minimum Slope (%) and Min. Maximum
Downstream Structure (Inchesl Velocity (fps) Length {ft)
at Design Flow
• Inlet to CB/MH 12 `�0.5°�, 3.0 fps 60
. . `• Inlet to CB/MH 8 0.5°k, 3.0 fps 40
. �
� • . " CB to CB 8 0.5°�, 3.0 fps 100
"' CB/MH to CB/MH 12 0� 0.2%, 3.0 fps 300
greater
' King County maintained roadways: on cross-street connections from single inlets to main storm .
drain, the pipe shall generally be 12-inch minimum diameter, and single inlets shall be catch basins
with sumps. In special cases, such as shallow gradients or conflict with underground utilities, pipe
may be minimurn 8-inch diameter, and inlet may be sirnple inlet (KCRS Dwg. No. 40).
" 8-inch-diameter pipe typically allowed only for privately maintained systems, except as noted (').
'" Maximum spacing of surface drainage courses between inlets or catch basins shall be 150 feet on �'
grades less than 1% and 200 feet on grades from 1 % to 3%. Otherwise, maximum spzcing shall �
be 300 feet on grades over 3°k, or as req�.:�r-� ��� �ra-e .. ca����•�_s � I
� 4.3.4-3 11/9�
KING COUNTY, WASHINGT01, SURFACE \� ATER DE51GN T�9ANUAL
TABLE 4.3.48 MAXIMUM PIPE SLOPES AND VELOCITIES
Pipe Material Pipe Slope Above 1Nhich Pipe Max. Slope Max. Velocity
Anchors Required and Allowed @ Full Flow
Minimum Anchor Spacing
' CMP, 'Spiral Rib, 20% 30°k"` 30 fps
'PVC, CPEP-singlewall (1 anchor per 100 L.F. of
pipe) '
'Concrete or •CPEP- 10°k 20%•'• 30 fps
smooth interior (1 anchor pEr 50 L.F. of pipe)
Ductile Iron 40% None None
(1 anchor per pipe section)
High Density Polyethylene 50% �one None
"HDPP (1 anchor per 100 L.F. of pipe
- cross slope installations only)
` Not�allowed in Iandslide hazard areas.
'` Butt-fused pipe joints required. Above-ground iristallation is required on slopes greater than 40°!0
to minimize disturbance to steep slopes.
••' Maximum slope of 200°� allowed for these pipe materials v�ith no joints fone section) with
structures at each end and properly grou;ed.
TABLE 4.34C ALLOWABLE STRUCTURES AND PIPE SlZES
Maximum Pipe Diameter
� '�'CMP, Spiral
Rib CPEP, � Concrete and
Catch Basin Type"' HDPP, PVC Ducti{e Iron
Inlet"� 12^ 12"
Type 1`=' 18" 12"
Type 1 L"' 24" 18"
Type 2-48-inch dia. 30" 24"
Type 2-54-inch dia. 36" 30"
Type 2-72-inch dia. 54" 48"
Type 2-96-inch dia. 72" 72"
"� Catch basins, including manhole steps, ladder, and handho(ds shall '
conform to King County Road Standards.
'�' Generally these pipe materials will be one size larger than concrete
due to smaller wall thickness. However, for angled connections or
those with several pipes ori the same plane, this will not apply.
'�' Maximum 5 vertical feet altowed between grate and invert
elevation. ;
i
"' Normally allowed only for use in privately maintained drainage
systems and must discharge to a C.B. immediately downstream.
(see Table 4.3.4A)
� �.3.4-�3 l l/93
KING COUNTY, �VASHINGTON, SURFACE 1�IATER DESIGN MANUAL
TABLE 4.3.4V MANNiNG'S "n" VALUES FOR PIPES
Analysis Method
Type of Pipe Material Uniform Backwater
Fiow Flow
(Preliminary (Capacity ,
design) Verification)
A. Concrete pipe and CPEP-smooth interior pipe ' 0.014 0.012
B. Annular Corr�gated Metal Pipe or Pipe Arch:
1. 2-2/3" x 1/2" corrugation (riveted)
a. plain or fully coated 0.028 0.024
b. paved invert (40% of circumference paved):
� 11) flow full depth 0.021 0.018
(2) flow 0.8 depth 0.018 0.016
(3) flow 0.6 depth 0.015 0.013
c. treatment 5 0.015 0.013
2. 3" x 1" corrugation 0.031 0.027
3. 6" x 2" corrugation (field bolted) 0.035 0.030
C. Helical 2-2/3" x 1/2" corrugation and CPEP-single wall 0.028 0.024
D. Spiral rib metal pipe and PVC pipe 0.013 0.011 �
E. Ductile iron pipe cement lined 0.014 0.012 I
F. High density polyethylene pipe Ibutt fused only) 0.009 0.009
�2} Backwater Analysis Method
Used to analyze the capacity of both proposed, and existing, pipe systems to convey the peak
rate of runoff for the 25, and 100-year design storm events., (Note, structures for proposed
�pipe systems must be demonstrated to provide a minimum of 0.5 feet of freeboard between
the headwater surface ihydraulic grade line) and the top of the structure for the 25 year peak
rate of runoff. Structures may overtop for the 100-year peak rate of runoff as allowed by Core
Requirement �J4 in Section 1.2.4. When overtopping occurs for the 100-year peak rate of
runoff the additional flow over the ground surface is analyzed using the methods describe '
Secti�_ - ,. , — — - -- - - - -- - - -- --- -�
belo��.
Thismetho� ... __�.. ._ �_ _... .. ..... , ,� ....__,.�._, �. _., _ , ; . �.. _ � ��_ ,.,.�, .,,. ..�.,.� � ;...:r.._
or existing, pipe system for the purposes of verifying adequate capacity. Ii incorporates a re-arran��d
form of Manning's Equation expressed in terms of friction slope (ie, slope of the energy grade line ;,��
ft/ftl. The friction slope is used to determine the head loss in each pipe segment due to barrel
friction, which can then be combined with other head losses to obtain water surface elevations at a'i
structures along the pipe system.
The backwater analysis begins at the downstream end of the pipe system and is computed back
through each pipe segment and structure upstream. The friction, entrance and exit head losses
computed for each pipe segment are added to that segment's tailwater elevation (the water surface
elevation at the pipe's outlet) to obtain its "outlet control" headwater elevation. This elevation is
then compared with the "inlet control" headwater elevation, computed assuming the pipe's inlet
alone is controlling capacity using the methods for inlet control presented in Section 4.3.5. The
condiiion that creates the highest headwater elevation then determines the pipe's capacity. The
approach velocity head is then subtracted from the controlling headwater elevation and the junction
and bend head losses are then added to compute the total headwater elevation which is then used as
the tailwater elevation for the upstream pipe segment.
� 4.3.4-16 11/92
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TABLE 3.5.2C "n" AND "k" VALUFS USED IN TIME CALCULATTONS FOR HYDROGRAPHS
'n;Sheol flow Equation Marv�n9 s Values(For tM kJtlal 300 h d travel) n�•
Srt+ooth suAa�es(eonueie,asptWt,pravel,or bara hard packed soi) A.Ot t
Fanow fields a loose ao1 svface(no resldue) 0.05
Cuhivs�ed soi with resldue eovet(s<.0.20 ft/h) 0.06 •
c,i,wa�ed soe.�nn resaw cwer{s> 0.20 h/h) 0.17
Short pa'rie�ass and lawns 0.15
Oense qrasses oZ�
Bermuda yrass 0.�1
Ranqe(naturaq D.t�
Woods or torest with liqhi underbrush 0.�0
Woods or foreri wah dans�underbrush 0.80 �
•Manrtirq values Ior sneet flow only,Irom Ovenon and Meadowz 1976(See TR-S5,�986)
'k'Values Vsed In Travel Time/T'me d Coneernntbn Calcutations
Shallow Concentroted Flow (Alter the fNUal 300 fL of sAeet Ilow.R .0.1) k�
1. faest with Aeavy p�ourd liaer an0 rtfeadows(n�0.10) a
2. Bnnhy Q�ax+d wGh sortie Irees(n-0.060) S
3. FaUow a m�nimum t11aQe a/tYvaCan(n�0.010) ��� 8
I. Hiph prasa(n•0.015) � 9
S. Short prass,pastwe and lawns(n-0.030) ]i �
Q Npdy bare pround(n.0.025) 13 � �I
7. Paved ond qav�t areas(n-O.Ot2) 27 I
Charuiel Flow¢mernJtten�j(At tne Cc�huwnq d visid�clnnneis:R-02) k� '
t. Fores�ed swale wuh Aeavy�ound lina(n . 0.10) 5
4, fac.ted Gra'vuqe course/ravine whh definod channol bed(n-0.050� 10
�. Roek-tlnod waicrway(n.D.WS) i5
�. Gnssed waterway(n.0.0�0) 17
5. EanA-0ned waierway(n•0.025) 2p
6. CMP pipe(n.0.02<) 21
7. Conerete p�pe(O.Ot2) , !2
0. O�her waterv+ays and pipes � 0.508/n
Channel Flow(Cantimntts strearq R .0.1) k�
9. Meanderinfl siream whh sorne pools(n-0.0�0) � 20
t0. Fiock�Ned ztream(n.p.Oli) �
11. G�assXu+ed stream(n-0.070) 27
... C,wr su�.-�s.-an•cb�e c`,i:inE:z�.:,:?z 0.8^��n•
••Sa�Chaptx S.iade 5.3.6C for addhlonat Alanninps'n'values lor open cl+amels
35.2-7 ��
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�-
MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES
MAINTENANCE STANDARDS FOR RENTON SCHOOL
DISTRICT DRAINAGE FACILITIES AT RENTON HIGH
SCHOOL
N0. 1 -CATCH BASINS
Maintenance Defect Conditlons When Maintenance is Needed Results Expected When
Component Maintenance is performed
General Trash&Debris Trash or debris of more than 1/2 cubic foot which is No Trash or debris located
(Includes Sediment) located immediately in front of the catch basin immediately in front of catch
opening or is blocking capacity of the basin by basin opening.
more than 10°k
Trash or debris(in the basin)that exceeds 1/3 the No trash or debris in the catch
depth from the bottom of basin to invert the lowest basin.
pipe into or out of the basin.
Trash or debris in any inlet or ouUet pipe blocking Inlet and outlet pipes free of
more than 1/3 of its height Vash or debris.
Dead animals or vegetation that could generate No dead animals or vegetation
odors that could cause complaints or dangerous present within the catch basin.
gases(e.g.,methane). '
Deposits of garbage exceeding 1 cubic foot in No condition present which
volume would attract or support the
breeding of insects or rodents.
Structure Damage to Comer of frame extends more than 3/4 inch past Frame is even with curb.
Frame and/or Top Slab curb face into the sVeet(If applicable).
Top slab has holes larger than 2 square inches or Top slab is free of holes and
cracks wider than 1/4 inch(intent is to make sure cracks.
all material is running into basin).
Frame not sitting flush on top slab, i.e.,separation Frame is sitting flush on top
of more than 3/4 inch of the frame from the top slab.
slab.
Cracks in Basin Walls/ Cracks wider than 1/2 inch and longer than 3 feet, Basin replaced or repaired to
Bottom any evidence of soil particles entering catch basin design standards.
through cracks,or maintenance person judges that
structure is unsound.
Cracks wider than 1/2 inch and longer than 1 foot No cracks more than 1/4 inch
at the joint of any inleU outlet pipe or any evidence wide at the joint of inleUoutlet
of soil particles entering catch basin through pipe.
cracks.
SedimenU Basin has settled more than 1 inch or has rotated Basin replaced or repaired to
Misalignment more than 2 inches out of alignment. design standards.
Operations and Maintenance Manual 1 Renton High School
MAINTENANCE STANDARDS FOR PRNATELY'.bI.4INTAINED DRAINAGE FACILITIES �
N0. 1 -CATCH BASINS(CONTINUED)
Maintenance Defect Conditi�.:� ,<f:��; ..,_.,,_�.....:_� :� :�t��<<.: �-.���:�y �.ir««�: ;��:�::
Component Maintenance is performed
Fire Hazard Presence of chemicals such as natural gas,oil and No flamr,able ch��i;a's
gasoline. present
Vegetation Vegetation growing across and blocking more than No vegeta,ior bioc�c'rg c�an�,g
10%of the basin opening. to basin.
Vegetation growing in inleUoutlet pipe joints that is No vegetation or root growth
more than six inches tall and less than six inches present.
apart.
Pollution Nonflammable chemicals of more than 1/2 cubic foot No pollution present other than
per three feet of basin length. surface film.
Catch Basin Cover Cover Not in Place Cover is missing or only partially in place.Any open Catch basin cover is closed
catch basin requires maintenance.
Locking Mechanism Mechanism cannot be opened by on maintenance Mechanism opens with proper
Not Working person with proper tools.Bolts into frame have less tools.
than 1/2 inch of thread.
Cover Oifficult to One maintenance person cannot remove lid after One maintenance person can
Remove applying 80 Ibs.of lift;intent is keep cover from remove cover.
sealing off access to maintenance.
Ladder Ladder Rungs Ladder is unsafe due to missing rungs,misalignment, Ladder meets design standards
Unsafe rust,cracks,or sharp edges. and allows maintenance person
safe access:
Metal Grates Grate with opening wider than 7/8 inch. Grate opening meets design
(If Applicable) standards.
Trash and Debris Trash and debris that is blocking more than 20%of Grate free of trash and debris.
grate surface.
Damaged or Grate missing or broken member(s)of the grate. Grate is in place and meets
Missing. design standards.
Operations and Maintenance Manual 2 Renton High School
MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES
NO.2-CONVEYANCE SYSTEMS(PIPES&DITCHES)
Maintenance Detect Conditions When Maintenance is Needed Results Expected When
Compone�t Maintenance is Performed
Pipes Sediment 8 Debris Accumulated sediment that exceeds 20%of the Pipe cleaned of all sediment
diameter of the pipe. and debris.
Vegetation Vegetation that reduces free movement of water All vegetation removed so water
through pipes. flows freely through pipes.
Damaged Protective coating is damaged;rust is causing Pipe repaired or replaced.
more than 50%deterioration to any part of pipe.
Any dent that decreases the cross section area of Pipe repaired or replaced.
pipe by more than 20%.
Open Ditches Trash 8 Debris Trash and debris exceeds 1 cubic foot per 1,Q00 Trash and debris cleared from
square feet of ditch and slopes. ditches.
Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/fiushed of all
design depth. sediment and debris so that it
matches design.
Vegetation Vegetation that reduces free movement of water Water flows freely through
through ditches. ditches.
Erosion Damage to See'Ponds"Standard No.1 See"Ponds"Standard No. 1
Slopes
Rock Lining Out of Maintenance person can see native soil beneath Replace rocks to design
Place or Missing(If the rock lining. standards.
Applicable).
Catch Basins See"Catch Basins:Standard No.3 See"Catch Basins"Standard
No.3
Debris Barriers See"Debris Barriers'Standard No.4 See"Debris Barriers"Standard
(e.g.,Trash Rack) No.4
NO.3-GROUNDS(LANDSCAPING)
Maintenance Defect Conditions When Maintenance is Needed Results Expected When
Component Maintenance is Performed
General Weeds Weeds growing in more than 20%of the landscaped Weeds present in less than 5%
(Nonpoisanous) area(Vees and shrubs only). of the landscaped area.
Safety Hazard My presence of poison ivy or other poisonous No poisonous vegetation
vegetation. present in landscaped area.
Trash or Litter Paper,cans,bottles,totaling more than 1 cubic foot Area clear of litter.
within a landscaped area(trees and shrubs only)of
1,000 square feet
Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than
broken which affect more than 25°/a of the total 5%of total foliage with split or
foliage of the tree or shrub. broken limbs.
Trees or shrubs that have been blown down or Tree or shrub in place free of
knocked over. injury.
Trees or shrubs which are not adequately supported Tree or shrub in place and
or are leaning over,causing expcuure of the roots. adequately supported;remove
any dead or diseased trees.
Operations and Maintenance Manual 3 Renton High School