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M TECHNICAL INFORMATION REPORT
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Proposed Harper Engineering Building Expansion
700 S.W. 7th Street
Renton, WA 98055
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Prepared for: ',
Harper Engineering Co.
c�"�PPH���'Q�°i 700 S.W. 7th Street
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�s�`'�`��'��"� March 28, 2014
. Our Job No. 16585
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� x CIV1L ENGINEERING, LAND PLANNING,SURVEYING
18215 72ND AVENUE SOUTH KENT,WA 98Q32 (425)251-6222 (425)251-8782 FAX
� � �u� BRANCH OFFICES • TUMWATER,WA ♦ LONG BEACH,CA ♦ WAWUT CREEK,CA ♦ SAN DIEGO,CA
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TABLE OF CONTEId7S
1.0 PROJECT OVERVIEW
� Figure 1 —Technical Information Report(TIR)Warksheet
Figure 2 —Vicinity Map
Figure 3—Grading and Storm Orainage Plan
2.0 CONDIT[ONS ANQ REQUIREMENTS SUMMARY
2.1 Analysis of the Core Requirements
2.2 Anaiysis of the Special Requirements
3.0 OFF-SfTE ANALYSIS (SEE TECHNICAL INFORMA710N REPORT DATED MARCH 8, 2011)
4.0 FLOW CON7ROL AND WATER QUALITY FACILITY ANALYSIS
5.0 CONVEYANCE SYSTEM ANALYSIS
6.0 SPECIAL REPORTS AND STUDIES
N/A
7.Q OTHER PERMITS
N/A
$,0 ESC ANALYSIS AND DESIGN
� 9.0 COVENAN7S, DEDICATIONS, AND EASEMENTS
N/A
10.0 MAINTENANCE AND OPERATIQNS
N/A
APPENDIX"A'�
STORM CALCULATIONS
APPEND{X ��B��
TECHNICAL INFORMATION REPORT �ATED MARCH 8, 2011
16585.G01.doc
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1.0 PROJECT OVERVIEW
The proposed project site is approximately 2.21 acres in size located on the northwest corner of
S.W. 7th Street and Seneca Avenue S.W. within the city of Renton. More particularly, the site is
located within a portian of the southwest quarter of Section 18, Township 23 Narth, Range 5 East,
Willamette Meridian, city of Renfon, Washington.
The site is fairly triangular in shape with a large curving side located along the northern property
iine of the site, which is adjacent to a railroad right-of-way. S.W. 7th Street forms the project
site's southern boundary and there is an existing development located east of the project site.
This is a redevelopment project currently consisting of an existing building and associated parking
lot and landscaping areas. The proposal for this development is to modify the existing parking lot
and landscape area to expand the existing building. An area of existing asphalt pavement will be
removed for the building expansion with areas of landscaping afso being removed to modify the
existing parking lot. The total area of irnpervious surface subject to vehicular traffic will be slightly
reduced with this project. There is already an existing conveyance system located on the site
that routes all stormwater runa#f into a detentio�i vault sized in accordance with the 1990 King
County, Washington Surfa�e Water Design Manual (KCWSWDM) in March 2001. Please refer to
the grading and drainage plan located in this report for an explanation of how the site will be
configured under the new developed conditions.
This project site is not increasing the amount of impervious surface by more than
5,000 squa�e feet and as it will afso decrease the amount of impervious surface subject to
vehicular traffic, there are no modifications proposed to the detention vault located in the center
portion of the project site, which discharges into S.W. 7fh Street.
Pursuant to the 2009 KCWSWDM, a praject is exempt from new flow contral facilities if the
project will result in less than 0.1 cfs increased flow from the existing site conditions. Calculations
are included in this report showing that this will be the case; however, flo�v control BMPs wilf still
be required and will inc[ude the use of pervious pavement and perforated downspout drains. As
mentioned previously, minor modifications will be made to the conveyance system and, as such,
pipe conveyance calculations have been provided showing that both the proposed and existing
pipes are sufficient to convey runoff from the project site to the existing detention vault.
The Technical Information Report for the original parking lot development and subsequent
redevelopment are attached herewith in Appendix A. Please refer to that documenf for how the
on-site facilities were sized for this project. The total increase in impervious surface with this
project is 411 square feet = 0.010 acre, with a net decrease of impervious surface subject to
vehicular traffic of 5,175 square feet = 0.066 acre.
16585.001.doc
FIGURE 1
TECHNlCAL INFORMATlON REP4RT (TIR)
WORKSHEET
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 1 PROJECT OWNER AND Part 2 PROJECT.l.00ATION AND
PROJECT ENGINEER DESCRIPTION
Project Owner Harper Enqineerinq Co. Project Name Har er En ineerin Buildin
Phone Expansion
Address 700 S.W. 7th Street DDES Permit#
Renton, WA 98055 Location Township 23 NorEh
Project Engineer Costa Philippides Range 5 East
Company Barghausen Consultinq Enqineers Section 18
, Inc. Site Address 700 S.W. 7th Street
Phone (425� 251-6222
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
❑ Landuse Services ❑ DFW NPA ❑ Shoreline
Subdivision / Short Subd. / UPD ❑ COE 404 Management
� Building Services ❑ DOE Dam Safety � Structural
M/F / Commercia / SFR RockeryNaulU
❑ Clearing and Grading ❑ FEMA Floodplain � ESA Section 7
❑ Right-of-Way Use ❑ COE Wetlands
❑ Other ❑ Other
Part 5 PLAN AND REPORT 1NFORMATION i
i Technical Information Report Site Improvement Plan {Engr. Plans)
` Type of Drainage Review Full I ar eted / Type (circle one): Full / odified /
�. (circle}: Large Site Small Site
; Date(include revision March 28. 2014 Date (include revision
' dates): dates):
Date of Final: Date of FinaL• ',
Part 6 ADJUSTMENT APPROVALS II
Type(circle one): Standard / Complex I Preapplication I Experimental ! Blanket
Description: (inciude conditions in TIR Section 2}
Date of A roval:
2009 Surface Water Oesign Manual 1/1109 '
1 16585.002.doc
KING COUNTY, WASHiNGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR} WORKSHEET
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes / N�
Describe:
Sta�t Date:
Completian Date:
Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan : Green River VaElev
Specia! District Overlays:
Drainage Basin: Green River
Stormwater Requirements:
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS !
i
❑ River/Stream ❑ Steep Slope
❑ Lake ❑ Erosion Hazard �
❑ Wetlands ❑ Landslide Hazard i
❑ Closed Depression ❑ Coal Mine Hazard
❑ Floodplain ❑ Seismic Hazard
❑ Other ❑ Habitat Protection
❑
Part 10 SOILS
Soil Type Slopes Erosion Potential
Woodinville Silt Loam
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❑ High Groundwater Table (within 5 feet) ❑ Sole Source Aquifer
❑ Other ❑ SeepslSprings
❑ Additional Sheets At#ached
2009 Surface Water Design Manual 1/1/09
2 16585.002.doc
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR} WORKSHEET
Part 11 DRAINAGE DESIGN LIMITATtONS
REFERENCE LIMITATION/SITE CONSTRAINT
❑ Core 2—Offsite Analvsis
❑ Sensitive/Critical Areas
❑ SEPA
❑ Other
❑
❑ Additianal Sheets Aftached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area)
Threshold Discharge Area: ;
(name or description Green River
Core Requirements(all 8 apply)
Dischar e at Natural Location Number of Natural Dischar e Locations; 1 f
Offsite Analysis Level: 1 / 2 / 3 dated: March 19, 2001
Flow Control Level: 1 I 2 I 3 or Exemption Number 1
(incl. facifity summary sheet) Smal! Site BMPs
Conveyance System Spill containment located at: Vault
Erosion and Sediment Control ESC Site Supervisor: TBD
Contact Phone:
After Hours Phone:
Maintenance and Operation Responsibility: Privat / Public
If Private Maintenance Lo Re uired: Yes / No
Financial Guarantees and Provided: Yes / No
Liabilit
Water Quality Type: 8asi I Sens. Lake / Enhanced Basicm 1 Bog
(include facility summary sheet) or Exemption No.
Landsca e Mana ement Plan: Yes / No
S ecial Requirements(as applicable)
Area Specific Drainage Type: CDA I SDO/MDP/ BP/ LMP/Shared Fac. / Non
Re uirements Name:
Floodplain/Floodway Delineation Type: Major I Minor / Exemption / None
100-year Sase Blood Elevation {or range):
Datum:
i
Flood Protection �acilities Describe: '
Source Control Describe landuse:
(comm./industrial fanduse} Describe any structural controls:
2009 Surface Water Design Manual 1/1/09
3 16585.002.doc
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNlCAL INFORMATION REPORT (TIR} WORKSHEET
�
Oil Control High-use Site: Yes / N I
Treatment BMP:
Maintenance Agreement: Yes / No
with whom?
Other Drainage Structures
Describe:
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION AFTER CONSTRUCTION
❑ Clearing Limits � Stabilize Exposed Surfaces
❑ Cover Measures ❑ Remove and Restore Temporary ESC Facifities
� Perimeter Protection � Clean and Remove All Silt and Debris Ensure
❑ Traffic Area Stabilization Operation of Permanent Facilities
� Sediment Retention ❑ f�ag Limits of SAO and open space
preservation areas
❑ SurFace Water Control
❑ Other
❑ Dewatering Control
❑ Dust Control
❑ Flow Control
Part 14 STORMWATER FACILITY DESCRIPTI�NS Note: Include Facili Summa and Sketch �
Flow Cantrol T e/Descri tion Water Quali T e/Descri tion
❑ Detention ❑ Biofiltration
❑ Infiltration � Wetpool Ex. Vault
❑ Regional Facility ❑ Media Filtration
❑ Shared Facility ❑ Oil Control
� Flow Control Ex. Vault ❑ Spill Contral
BMPs
❑ Flow Control BMPs
❑ Other
❑ Other
2009 Surface Water Design Manual 1/1/09
4 16585.002.doc
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REP�RT (TIR) WORKSHEET
Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS
❑ Drainage Easement ❑ Cast in Place Vaulf
❑ Cavenant ❑ Retaining Wall
❑ Native Growth Protection Covenant ❑ Rockery> 4' High
❑ Tract ❑ Structurai on Steep Slope
❑ Other ❑ Other
Part 17 SiGNATURE OF PROFESSIONAL ENGINEER
1, or a civil engineer under my supervision, have visited the site. Actual site conditians as observed were
incorporated into this worksheet and the attached Technical Infarmation Report. To the best of my
knowledge the information provided here is accurate.
S' ned/Date
I
20Q9 Surface Water Design Manuai 1/11a9
5 3 6585.002.doc
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B�.E. JOB NO. 16585
2.0 CONDITIONS AND REQUIREMENTS
SUMMARY
2.0 CONDITIONS AND REQUIREMENTS SUMMARY I
2.1 Analysis of the Eight Core Requirements
Core Requrrement Alo. �: Drscharge af the Nafural Location.
Response: This project is a minor redevelopment of a currently developed site and wili
not change the current discharge location of the existing storm system.
Core Requirement IVo. 2: Off-Sife Analysis.
Response: An off-site analysis was performed for #his project site during the originai
development and is included in Appendix B of this report.
Core Requirement IVo. 3: FJow Confrol.
Response: This project is seeking an exception for flow contro! pursuant to Section 1.2
of the City of Renton Amendments to the KCWSWDM pursuant to the attached
calculations the improvements proposed for this project will not increase the 100-year
storm discharge by more than 0.1 cfs.
Core Requrrement No. 4: Conveyance System.
Response: The conveyance system for this site will meet all requirements for conveying
the 100-year storm e�ent.
Core Requirement No. 5: Erosio��and Sedimenf Control.
Response: Erosion and sedimentation control measures in accordance with the
2009 KCWSWDM will be instituted on this project site so that catch basin inserts will be
used fo ensure that no sediment laden water will enter the existing sform system.
Core Requiremenf No. 6: Mainfenance and Operations. I
Response: This project will concur with all maintenance and operations requirements of
the City of Renton for projects of this nature.
Core Requirement No. 7: Financial Guarantees and Liabilify. '
Response: This project wil! concur with all financial guarantees and liabifities I
requirements of the City of Renton for projects of this nature. �
Core Requirement No. 8: Water Qualrty.
Response: As the proposed project wil! actual(y decrease the amount of pollution
generating surface by 5,175 square feet, the existing water quality feature �vill provide the
needed protection.
� 16585.001.doc
2.2 Analysis of the Five Specia( Requirements
Special Requirement No. 1: OtherAdopfed Area-Specific Requiremen[s.
Respanse: There are no known other adopted area-specific requirements associated
with this development.
Specia!Requirement No. 2: Flood Hazard Area Delineation. '
Response: This project is not in a known Flood Hazard Area
Specra!Requirement No. 3: Flood Protection Facilitres.
Response: This project does not meet the threshold of fhis requirement.
Specra!Requrrement No. 4: Source Control.
Response: This project will provide source control measures where required.
Special Requiremenf No. 5: Oi!Control.
Response: This project is not a high-use site nor is it a redevelopment project proposing
improvements to an existing high-use site; therefore, the threshold of this requirement is
not met.
16585.001.dac
3.0 OFF-SITE ANALYSIS {SEE TECHNICAL
INFORMATl4N REPORT DATED MARCH 8, 2011 }
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3.0 OFF-SITE ANALYSIS
See Technical Infonr�ation Report dated Nlarch 28, 2014.
4.4 FLflIN CONTROL AND 1NATER QUALITY
FACILITY ANALYSIS
4.0 FLOW CONTROL AND WATER QUALITY FACILI7Y ANALYSIS
Pursuant to Section 5.2.1.3 of the 2009 KCWSWDM, Flow Control BMPs must be appliecf to the
targeted impervious surface (411 square feet of ne�v impervious surface). Also, 20% of the targef
impervious surface area must have a Flow Control BMP applied. This project is proposing
perforated downspaut pipes an the new roof drains.
16585.001.doc
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5.0 CONVEYANCE SYST�M ANALYSIS AND
DESIGN
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
The entire site was previously analyzed for conveyance capability utilizing the modified rational
method as required in the 2009 KCWSWDM for sites less than 10 acres in size with a 100-year
precipitation of 3.9 inches, an initial t;me of concentration of 6.3 minutes, and a Manning's 'n'
value of 0.014 (all pipes conveyed the ffaws contributing to them). Since the proposed
development will not increase the impervious pavement area by any significant amount, the
previous pipe sizing �vas used for the nevr pipe runs.
6.0 SPECIAL REPORTS AND STUDIES
, 6.0 SPECIAL REPOR7S AND STUDIES
Nut appllcable
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7.0 OTHER PERMITS
Not applicable.
16585.00t.dec
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8.0 ESC ANALYS[S AND DESIGN
8.0 ESC ANALYSIS AND DESIGN
Since this is a redevelopment project and there is less than 1 acre of area that will be disturbed
on this project site, required erosion control measures wi{I be at a minimum. Since mostly
impervious surface will be removed and replaced almost immediately, the only proposed erosion
control rneasure to be followed on this project site is fo utilize catch basin inserts for the new and
existing catch basins proposed for this development.
The TESC/demolition plan cleariy indicates the area to be demolished and disturbed for this
project. Please refer io that sheet for the proposed erosion control measures to be uti'ized with
this deve�opment.
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9,0 COVENANTS, DEDICATlONS, AND
EASEMENTS
' 9.0 COVENANTS, DEDICATIONS,AND EASEMENTS
Not applicable.
?6585.001.doc '
1 Q.Q MAINTEIVAN�E AN� OPERATI�NS
'f0.0 MAfNTENANCE AND OPERATIONS �
Not applicable.
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16585.001.doc
APPENDIX A
ST�RM CALCULATIONS
FLOW CONTROL SlZING CRITERIA
FOR THE AREA OF REDEVELOPMENT
Existing Conditions (Pre)
Asphalt = 8,929 SF = 0.205 Acre
Landscaping = 1,240 SF = d.028 Acre
Totals = 10,169 SF = 0.233 Acre
Proposed Conditions (Dev)
New Asphalt = 3,754 SF = 0.214 Acre
New Building = 5,586 SF
Nevr Landscaping = 829 SF - 0.019 Acre
Totals = 10,169 SF = 0.233 Acre
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�CRTS Command
CREATE a new Time Ser�es
------------------------
?roduction of Runoff Time Series
Froject Lccation : Sea-Tac
Computing Series : 16585existi�g.tsf
?2egicr_a? Scale Factor : 1. OG
Data Type : Reduced
Creating 15-minute Time Series File
Loading Time Series File:C: \KC SWDM\KC DATA\STTG15R.rnf .
Till Grass 0.03 acres
Loading Time Series File:C:\KC SWDM\KC DATA\STEI15R.rr_f .
Impervious 0.20 acres
Total Area : 0.23 acres
Peak Discharge: 0.256 CFS at 6 :30 on Jan 9 in Year 8
Storing Ti�re Series File:16585existir_g. tsf .
Time Series Comt�uted
KCRTS Command �I
' Enter the Analysis TOOLS Module '
-------------------------------
Ana�ysis Tools Command
' ----------------------
Cor.,pute PEAKS and Flow Frequencies
----------------------------------
Loading Stage/Discharge curve:16585existing.tsf .
Flow Frequency Analysis
--------------------------------------------------------
Time Series File:16585existing.tsf
Project Location:Sea-"'ac
Frequencies & Peaks saved to File:16585existing.pks .
Analysis Tools Command �
----------------------
RETURN to Previous Menu
-----------------------
KCRTS Command
CREATE a new Time Series •
------------------------
?roduction of Runoff Time Series
Project Location : Sea-Tac
Compu�ing Series : 16585dev.tsf
Regional Scale Factor : 1,OQ
Data Type : Reduced
Creating 15-minute Time Series File
Loading Time Series File:C:\KC SWDM\KC DATA\STTGiSR.rnf .
Til' Grass 0 . 02 acres
Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI15R.rnf .
Impervious 0.21 acres
Total Area : 0.23 acres �,
Peak Discharge: 0.262 CFS at 6:30 on Jan 9 in Year 8
Storing Time Series File: 16585dev.tsf .
Time Series Computed
KCRTS Command
Enter the Analysis TOOLS Module
-------------------------------
Analysis Tools Command
----------------------
Compute PEAKS and Flow Frequencies
----------------------------------
Loading Stage/Discharge curve: 16585dev.tsf .
�'low Frequency Analysis
--------------------------------------------------------
Tirne Series File:16585dev.tsf
Project Location:Sea-Tac
Frequencies & Peaks saved to File:16585c3ev_pks .
Analysis Tools Command
RETURN to Previous Menu
-----------------------
KC3ZTS Command
eXit KCRTS Program i
------------------
Flow Frequency Analysis
Time Series File: 16585existing.tsf
Project Location:Sea-Tac
---An�-�ual Peak Flow Rates--- -----Flow Frequency Analysis-------
Flow Rate Ran�c Time of Peak - - Peaks - - Rank Return Prob
{CFS) (CFS) Period
b.098 b 8/27/Ol 18:00 0 .256 1 100.00 0 .990
0.068 8 9/17/02 17:45 0 .191 2 25 .00 0 .960
0.191 2 12/08/02 17:15 0 .133 3 10 .00 0 .900
� 0.078 7 $/23/04 14:30 0.111 4 S .Oa 0. 8C0 �
0.105 5 10/28/04 16:00 0.105 5 3 .00 0.667
0.111 4 10/27/05 10:45 0.098 6 2.00 0.500
0.133 3 10/25/06 22:45 0.078 7 1.30 0.231
0.256 1 }/09/OS 6:3C 0.068 8 1. 10 0.091
Computed Peaks 0.234 50.00 0_980
Flow Frequency Analysis
Time Series File: 16585dev.tsf
Project Location:Sea-Tac
---Anr_ual Peak Flow Rates--- -----Flow �requency Analysis-------
Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS} Period
0 .102 6 8/27/Ol 18:00 0.262 1 100 .00 0 .990
0.071 8 9/17/02 17:45 0. 197 2 25 .00 0 . 960
0.197 2 12/08/02 17:25 Q. 139 3 10 .00 0 . 900
' 0.082 7 8/23/04 14:30 Q. 115 4 5 .00 0.800
0.109 5 10/28/04 16:00 O. 1Q9 5 3 .00 0 .667
0.115 4 10/27/05 10:45 4. 102 6 2 .00 0 .500
0.139 3 10/25/a6 22:45 0. 082 7 1.30 0.231
0.262 1 1/09/08 6:30 4. 071 8 1.10 0.091
Computed Peaks 4.240 50 .00 0. 980
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APPENDIX B
TECHNICAL INFORMATI�N REPaRT DATED
� MARCH 8, 2011
{
� 7
TECHNICAL INFORMATION REPORT ;
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Proposed Harper Engineering Building Expansion
700 S.W. 7th Street i�
Renton, Washington ,
Prepared for:
Harper Engineering Co.
�,�PpHILlpp�O 700 S.W. 7th Street
�o t,,� ������,,; F�, Renton, WA 98055
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,��-.,,�ti.�t `,.-
�� ''���:��•��' Revised March 8, 2011
Our Job No. 15011
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� Z► CIVIL ENGINEERING,LAND PLANNING,SURVEYING, ENVIRONMENTAL SERVICES
� � - 18215 72ND AVENUE SOUTH KENT,WA 98032 (425)251-6222 (425)251-8782 F�Uc
Z i BRANCH OFFICES ♦ OLYA�IA,WA ♦ SACRAMENTO,CA ♦ TEMECULA,CA
+� ,,• www.barghausen.com
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TABLE OF CONTENTS
1.0 PROJECT OVERVIEW
Figure 1 —Technical Information Report (TIR) Worksheet
Figure 2—Vicinity Map
Figure 3—Grading and Storm Drainage Plan
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
2.1 Analysis of the Core Requirements
2.2 Analysis of the Special Requirements
3.0 OFFSITE ANALYSIS (SEE TECHNICAL INFORMATION REPORT DATED JULY 6, 2007)
4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
6.0 SPECIAL REPORTS AND STUDIES
N/A
7.0 OTHER PERMITS
N!A
8.0 ESC ANALYSIS AND DESIGN
9.0 COVENANTS, DEDICATIONS, AND EASEMENTS
N/A
10.0 MAINTENANCE AND OPERATIONS
N/A
APPENDIX ��A��
STORM CALCULATIONS
APPENDIX ��B'�
TECHNICAL INFORMATION REPORT DATED JULY 6, 2007
15011.001.doc
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1.0 PROJECT OVERVIEW
The proposed projecf site is approximately 2.21 acres in size located on the northwest corner of
S.W. 7th Street and Seneca Avenue S.W. within the City of Renton. More particuiarly, the site is
located within a portion of the Southwest quarter of Section 18, Township 23 North, Range 5
East, Willamette Meridian, City of Renton, Washington.
The site is fairly triangular in shape with a large curving side located along the northern property
line of the site, which is adjacent to a railroad right-of-way. S.W. 7th Street forms the project
site's southern boundary and there is an existing development located east of the project site.
This is a redevelopment project currently consisting of an existing building and associated parking
lot and landscaping areas. The proposal for this development is to modify the existing parking lot
and landscape area to expand the existing building. An area of existing asphalt pavement will be
removed for the building expansion with areas of landscaping also being removed to modify the
existing parking lot. The total area of impervious surface subject to vehicular traffic will be slightly
reduced with this project. There is already an existing conveyance system located on the site
that routes all stormwater runoff into a detention vault sized in accordance with the 1990 King
County, Washington Surface Water Design Manual (KCSWDM) in March of 2001. Please refer to
the grading and drainage plan located in this report for an explanation of how the site will be
configured under the new developed conditions.
This projec# site is not increasing the amount of impervious surface by more than 5,000 square
feet, and as it will also decrease the amount of impervious surface subject to vehicular fraffic,
there are no modifications proposed to the detention vault located in the center portion of the
project site, which discharges into S.W. 7th Street.
Per the 2009 King County Surface Water Design Manual, a project is exempt from new flow
control facilities if the project will result in less than 0.1 cfs increased flow from the existing site
conditions. Calculations are included in this report showing that this wil( be the case. However,
Flow Control BMP's will still be required and will include the use of pervious pavement and
perforated downspout drains. As mentioned previously, minor modifications will be made to the
conveyance system, and as such, pipe conveyance calculations have been provided showing
that both the proposed and existing pipes are sufficient t� convey runoff from the project site to
the existing detention vault.
The Technical Information Report for the original parking lot development and subsequent
redevelapment are attached herewith in Appendix A. Please refer to that document for how the
on-site facilities were sized for this project. The total increase in impervious surface with this
project is 1,097 square feet= 0.025 acre, with a net decrease of impervious surface subject
vehicular traffic of 2,643 square feet=d.06 acre.
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15011.001.doc
FIGURE 1
TECHNICAL INFORMATION REPORT (TIR)
W�RKSHEET
KING COUNTY, WASHtNGTON, SURrACE WATER DESIGN NIANUAL �
TECHNICAL lNFORMATION REPORT (TIR) WORKSHEET
Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND '
PROJECT ENGINEER DESCRIPTION �'
Projec#Owner Harper En�ineering Co. Pro}ect Name Hai• er Eil iiieerin> Buildin
Phone Expansion
Address 700 S.W. 7th Street DDES Permit#
Renton, WA 98055 Location Township 23 Nort11
Project Engineer Costa Philippides Range 5 East
Company BarQhausen Consulting En�ineers, LZc. Section 18
Phone (425) 251-6222 Site Address 700 S.�V. 7th Street
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
❑ �anduse Services ❑ DFW HPA ❑ Shoreline
Subdivision / Short Subd. ( UPD ❑ COE 404 Management
� Building Services ❑ DOE Dam Safety � Structural
M/F J Commercial / SFR RockeryNault/
❑ Cfearing and Grading ❑ ��MA Floodplain � ESA Section 7
❑ COE Wetlands
❑ Right-of-Way Use ❑
Other
❑ Other
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review Full I Tar eted ! Type (circle one): Full I Modifie J '
(circle): Large Site Small Site
Date (include revision Januaiy 4, 2011 Date (include revision
dates): dates):
Date of Fina{: Date of Final:
Part 6 ADJUSTMENT APPROVALS
Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket
Descriptton: (include conditions in TIR Section 2)
Date of Approval:
2009 Surface Water Desijn Manual VV09
1 1 SOl 1.002.doc
I<ING COUNTY, WASHINGTON, SURFACE WA"I�ER DESIGN MANUAL
TECHNICAL fNFORMATION REPORT (TIR) WORKSHEET
Part 7 MONITORfNG REQUIREMENTS
Monitoring Required: Yes / No
Describe:
Start Date:
Compietion Date:
� Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan : Green River Vallev
Special District Overlays:
, Drainage Basin: Green River
' Stormwater Requirements:
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
❑ River/Stream ❑ Steep Slope
❑ �ake ❑ Erosion Hazard
❑ Wetiands ❑ Landslide Hazard
❑ Closed Depression ❑ Coal Mine Hazard
❑ Floodplain ❑ Seismic Hazard
❑ Other ❑ Habitat Protection
❑
� Part 10 S�1LS
Soil Type Slopes Erosion Potential
VVoodinville Silt Loam
❑ High Groundwater Table (within 5 feet) ❑ Sole Source Aquifer
❑ Ofher ❑ SeepslSprings
� ❑ Additional Sheets Attacned
' - -- -
2009 Surface �Uater Design Manual 1iU09
2 1501 1.002,doc
KING COUN`I'Y, WnS�IINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 11 DRAINAGE DESIGN LfMITATIONS
REFERENCE LIMITATION /SITE CONSTRAINT
❑ Core 2 —Offsite Analysis
❑ SensitiveJCritical Areas
❑ SEPA
❑ Other
❑
❑ Additiona! Sheets Attached
Part 12 TIR SUMMARY SHEET (pro�ide one TIR Summary Sheet per Threshold Discharge Area)
Threshold Discharge Area:
(name or description) Green River
Core Requirements(all 8 app(y)
Dischar e at Natural Location Number of Natura! Dischar e Locatians: I
Offsite Analysis Level: 1 / 2 / 3 dafed: March 19, 2001
' Flow Control Level: 1 / 2 / 3 or Exemption Number 1
(incl. facility summary sheet) Small Site BMPs
Conveyance System Spill containment located at: Vault
Erasion and Sediment Control ESC Site Supervisor: TBD
Contact Phone:
After Hours Phone:
Maintenance and Operation Responsibility: Privat / Public
!f Private, Maintenance Lo Re uired: Yes / No
Financial Guarantees and Provided: Yes / No
Liability
Water Quality Type: Basi I Sens. Lake / Enhanced Basicm / Bog
(include facility summary sheet) or Exemption No.
Landsca e Mana ement Plan: Yes / No
Special Requirements (as appiicable)
Area Specific Drainage Type: CDA/SDO/ MDP/ BP / LMP 1 Shared Fac. I Non
Requirements Name:
Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None
100-year Base Blood Elevation (or range):
Datum:
Flood Protection Facilities Describe:
Source Control Describe landuse: �
i {comm./industrial landuse) Describe any structura! controls:
2009 Surface ��ater Desi�n �lanual 1/Ii09
3 I��1 1.f�02 doc
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET ,
Oil Control High-use Site: Yes / N I�
Treatment BMP: I
Maintenance Agreement: Yes / No ',I
with whom?
Other Drainage Structures
Describe:
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION 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
❑ Traffic Area Stabilization Operation of Permanent Facilities
� Sediment Retenfion ❑ Flag Limits of SAO and open space
preservation areas
❑ Surface Water Control � Other
❑ Dewatering Control
❑ Dust Control
❑ Flow Control
Part 14 STOFtMWATER FACILITY DESCRIPTIONS Note: Include Facilit Summa and Sketch
Flow Controi T e/Descri tion Water Qualit T e/Descri tion
❑ Detention ❑ Biofiitration
❑ Infiltration � Wetpool Ex. Vault
❑ Regional Facility ❑ Media Filtration
❑ Shared Facility ❑ Oif Control
� Flow Control Lx. Vault ❑ Spill Control
BMPs
❑ Flow Control BMPs
❑ Other
� ❑ Other
2009 Surface Water Design Manual l/l/U9
4 1501 I.002.doc
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS
❑ Drainage Easement ❑ Cast in Place Vault '
❑ Covenant ❑ 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 aftached Technical Information Report. To the best of my
knowledge the information provided here is accurate.
Si ned/Date
�009 Surfacc �lratcr Design ?��lanual 1/1/09 �
5 1�Ol 1.002.doc I
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FIGURE 3
GRADING AND STORM DRAINAGE PLAN
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i a � Y � 'r ���I;I j'�! N HARPER ENGINEERiNG ADDITION ��
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2.0 CONDITIONS AND REQUIREMENTS
SUMMARY
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
2.1 Analysis of the Eight Core Requirements I
Core Requirement No. 1: Discharge at the Nafural Location. ',
Response: This project is a minor redevelopment of a currently developed site and will
not change the current discharge location of the existing storm system. ',
Core Requirement No. 2: Off-Sife Analysis. I
Response: An off-site anaiysis was performed for this project site during the original ,
development and is included in Appendix B of this report. '
Core Requirement No. 3: Flow Control.
Response: This project is seeking an exception for flow control per Section 1.2 of the
City of Renton Amendments to the King County Surface Water Manual as per fhe
attached calculations the improvements proposed for this projecf will not increase the
100-year storm discharge by more than 0.1 cfs.
Core Requirement No. 4: Conveyance System.
Response: The conveyance system for this site will meet all requirements for conveying
the 100-year storm event.
Core Requrrement IVo. 5: Erosion and Sedimenf Control.
Response: Er�sion and sedimentation control measures in accordance with the 2009
King County Surface Water Design Manual will be instituted on this project site so that
catch basin inserts wi11 be used to insure that no sediment laden water will enter the
existing storm system.
Core Requirement No. 6: Maintenance and Operations.
Response: This project will concur with all maintenance and operations requirements of
the City of Renton for projects of this nature.
Core Requirement No. 7: Financiaf Guaranfees and Liability.
Response: This project will concur with all financial guarantees and liabilities
requirements of the City of Renton for projects of this nature.
Core Requirement No. 8: Water Quality.
Response: As the proposed project will actually decrease the amount of pollution
generating surface by 2,643 sf the existing water quality feature will provide the needed
protection.
15011.001.doc
2.2 Analysis of the Five Special Requirements
Special Requirement No. 1: Ofher Adopted Area-Specific Requirements.
Response: There are no known other adopted area-specific requirements associated
with this development.
Special Requirement No. 2: Flood Hazard Area Delineation.
Response: This project is not in a known Flood Hazard Area
Speciai Requirement No. 3: Flood Protecfion Facilities.
Response: This project does not meet the threshold of this requirement.
Special Requirement No. 4: Source Control.
Response: This project will provide Source Control measures where required.
Special Requirement No. 5: Oil Control.
Response: This project is not a high-use site nor is it a redevelopment project proposing
improvements to an existing high-use site. Therefore the threshold of #his requirement is
no# met.
15011.001.doc
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3.0 OFFSITE ANALYSIS
See Technical information Report dated July 6, 2007
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15011.001.doc
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4.0 FLOW CONTROL AND WATER QUALITY �
� FACILiTY ANALYSIS
p 4.0 FLOW CONTROL AND WATER QUALITY FAC{LITY ANALYSIS II
Per Section 5.2.1.3 of the 2009 KCSWDM, flow control BMPs must be applied to the targeted
impervious surface (1,108 SF of new impervious surface}. Also, 20 percent of the target
impervious surface area must have a flow control BMP applied. This project is proposing 1,600
SF of porous asphalt, which is more than required. In addition to the porous asphalt, this project
is proposing perforated downspout pipes on the new roof drains.
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15011.001.doc
5.0 CONVEYANCE SYSTEM ANALYSIS AND �
DESIGN
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5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
The entire site was analyzed for conveyance capability utilizing the modified rational method as
required in the 2009 KCSWDM for sites less than 10 acres in size. A 100-year precipitation of 3.9
inches, with an initial time of concentration of 6.3 minutes and a Manning's "n" value of 0.014, all
pipes conveyed the flows contributing to them.
15011.001.doc
PIPE CONVEYANCE CALCULATIONS
. . .. .. _._.. . .. ...... -._. _ . . ...._... 1 .
1 SO11-7 OO.%IS
BARGHAUSEN CONSULTING ENGINEERS-PIPE FLOW CALCULATOR
using the Rational Method 8 Manning Fortnula
KING COUNTY DESIGN FOR 100 YEAR STORM
JOB NAME HARPER ENGINEERING NO?t F\T�R DEFA:�IiS FlN7 SIOR'•i�.lii;;�"�RG t3EGRvN�VG
JOR� 1501� DEFAULTS C= 0.9 n= 0014
Fi!.F NO 15011-100XLS d= 12 Tr.= 6.3
A=ContriDuGng Area(Ay Qd=Design Flow(cls) COEFF�CIENTS FOR THE RATIONAL METHOD'Ir"-E�UATION
G Runoff Coeffcient pf=full Capacity Flow(cfs) STORhi A�
Te=Tirtie ot Concentration(min) Vd=Velocity al Design Flow(ips) 'l.vR �5�+c p�C• �
1=Intensity at Tc(in/hr) Vh Velocity at Full Flow(ips) '�CVR 2•7�% 0 6�PRECIP= 3.9
d=Diameter o(Pipe(in) 5=Siope of pipe(k) 25YR _'dG .;i�Ar= 2.61
L=Length of Plpe(ft) n=Manning Roughness CoetficieN SCYR 2�5 ^.^.�Br= 0.63
D=Water DeDlh at Qd(in) Tt=Trevel Time at Vd(mm) 70GYR i.6� '.l Gt
FROM TO A s L d Tc n G SUM A A'C SUM A'C 1 Od Ot pd/Q( D/d D Vf Vd Tt
EXCB7 F>CC66 0.18 0.96 50 72 6.3 0.01a 0.9 053 0.16 0".0 31y G52 32a o.160 U.'tf8 3,21 4.13 3.07 0.28 �
EXC66 C61 0.06 0.35 40 12 6.6 0.074 0.9 ::24 0.05 D'2i 3.i1 G E7 1 9u 0.343 �405 4,R5 2AP :27 0.29
CB1 C62 0.15 0.35 49 12 6.9 OA�4 0.5 f„39 0.08 029 30Z C.88 196 0.450 0.471 5.65 2.49 245 033
CB2 C83 0.14 0.35 49 12 7.2 OA14 0.5 0.53 0.07 0.38 "J.5' �06 1 9G 0.54'I 0.52C 6.28 Z 39 2.5-0 0.32
C83 EXC69 0.10 0.35 40 12 7.5 0.014 0.45 .^.63 0.05 0.4', 2 B`. ' lfi t 56 0.592 0.553 8.G3 2.49 2.5? 0.26
EXC69 EXCBt 0 0.63 0.62 200 12 7.8 0.01a O.aS 7!C- 0.28 ^c`• �__ '?7 2(,r o.7ao G 6JD ?>8 3 32 'n's 0.92
EXC611 EXC670 0.27 1.67 85 �Z 6.3 0.074 0.75 ,�... 020 . .�. . �. ,.,.. a77 0.151 07�;7 3i3 c.15 '.�G 0.36
EXC810 EXC81 0.16 4.'19 31 15 8 7 0,074 0.9 0 t� 0.14 �G� 7>n .. ... ._,, 0.220 0.315 -.. 1!:�5" 9 DG 0.06
EXC85 ESCB4 0.14 0.97 60 12 6.3 0.014 0.9 G�a 0 73 ��i t:. ' . G 40 :5 7� 0.123 �;?3P i 8' �: t 5 _ ,_ 0.36
EXC84 EXC63 0.04 tA5 22 12 67 0.014 0.9 il i?1 OA4 0��' _.._ G�i0 3 3i! 0,747 0258 :.DS <7�2 i r'- OJ2
EXC63 EXCB2 U.09 1.04 68 12 6.8 0.07a 0.9 C 27 0.08 . , ...... '�:a 3.3? 0.220 G 31fi 3.79 �;i0 .... 0.33
EXCB2 EXCB7 0.17 5.92 25 12 7.1 0.014 0.9 .^.A4 0.75 ii=U . ._ . �, £305 Q.146 0.25(i ?.OS �02c. i 2fi 0.06
EXCBt EXMH� 0.05 0.36 36 15 8.8 0.014 0.9 Q:5 0.05 "t' ... . , .. 350 1.064 G.l15? t3:�9 [25 3'i7 018
�'age t
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PIPE CONVEYANCE BASIN MAP
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6.0 SPECIAL REPORTS AND STUDIES
6.0 SPECIAL REPORTS AND STUDIES
Not applicable.
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Not appficab!e.
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15011.001.doc
8.0 ESC ANALYSIS AND DESIGN
8.0 ESC ANALYSIS AND DESIGN
Since this ;s a redevelopment project and there is less than one �cre of area that will be disturbed
on this project site, required erosion control measures will be at a minimum. Since mostly
impervious surFace will be removed and replaced almost immediately, the only proposed erosion
control measure to be followed on this project site is to utilize catch basin inserts for the four new
catch basins proposed for this development.
The TESC/Demolition Plan clearly indicates the area to be demolished and disturbed for this
project. Please refer to that sheet for the proposed erosion control measures to be utilized with
this development.
15G11.001.doc
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9.0 COVENANTS, DEDICATIONS, AND
EASEMENTS
9.0 COVENANTS, DEDICATIONS, AND EASEMENTS
Not applicable.
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15011.001.doc
10.0 MAINTENANCE AND OPERATIONS
10.0 MAINTENANCE AND OPERATIONS
Not applicabie.
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15011.001.doc
APPENDIX A
STORM CALCULATIONS
FLOW CONTROL SIZING CRITERIA
FOR THE AREA OF REDEVELOPMENT
Existing Conditions (Pre)
Asphalt = 4,811 SF = 0.110 Acre
Landscaping = 1,572 SF = 0.036 Acre
Totals = 6,383 SF = 0.146 Acre
Proposed Conditions (Dev)
New Asphalt = 2,179 SF
= 0.136 Acre
New Building = 3,740 SF
New Landscaping = 464 SF = 0.010 Acre
Totais = 6,383 SF = 0.146 Acre
15011.001.doc
- -- — �
KCRTS Command i
CREATE a new Time Series
------------------------
Production of Runoff Time Series
ProjecL Locat.ion : Sea-Tac
CompuC.ing Series : 15011pre. tsf
lzegional Scale P'actor : 1.00
Data Type : Reduced
Creating Hourly Time Series File
Loading Time Series File:C: \KC__SWDM\KC_DATA\STTG60R.rnf .
Till Grass 0 .04 acres
Loading 'Pime Se.r.ies Ft1e:C: \KC_SWDM\KC_DATA\S'PEI60R.rnf .
_:npervious 0.11 acres
'I'otal Area : 0.15 acres
i�eak Discharge: 0 .060 CFS at 6:00 on Jan 9 in Year 8
Storing Time Series File:15011pre. tsf .
Time Series Computed
KCRTS Command
Enter tne Analysis TOOLS Module
-------------------------------
Analysis Tools Command
----------------------
Compute PEAKS and Flow Frequencies
----------------------------------
Loading Stage/D.ischarge curve: 15011pre. tsf .
Flow ;�'��equency Analysis
---------------------------------•-----------------------
'Pime Series File:15011pre.tsf
I'roject L,ocation: Sea-Tac
��:equencies & Peaks saved to File: 15011pre .pks .
:`�._zalvsis Tools Command
---------------------
RE:'1'URN to Previous Menu
KCRTS Command
CKEATE a new Time Series
------------------------
Production of Runoff Time Series
Project LocaLion : Sea-Tac
Computing Series : 15011dev.tsf
i�egional Scal� Factor : 1.00
Data Type : Reduced
;'reating Hourly Time Series File
Loading Time Series l�ile:C: \KC__SWDM\KC_DATA\STTG60R.rnf .
'Pi l.l c.;rass 0 . 01 acres
1_oading Time Se��.ies F:i1e:C: \I<C_SI�dD'tf\I<C_DATA\S�I'EIuOR . rnL .
Impervious 0 . 14 acres
--------------
Total Area : 0 ,15 acres
Peak Discharge: 0.066 CFS at 6: 00 on ,7ar_ 9 in Year 3
Storinq Time Ser�es �i1e: 15011d�v . tsL .
Time Series Computed
KCKTS Command
Eni�er the �'�nalysis TOOI,S :Kodule
:?r.�lysis Toc1s Com�and
----------------------
Compute PEAT{S and Flow Frequencies
----------------------------------
Loading Stage/D:ischarge cuiv:: 1�f)7 I de�, , tsf: .
Flow L�requency Analysis
Time Series File: 15011dev.tsf
Project Location:Sea-Tac
Frequencies & Peaks s��.red �o ri1�: i5011dev .pks .
Analysis Tools Comman�l
----------------------
RETURN to Previous Mer_u
-----------------------
ICCRTS Command
CREATE a new Time Ser:ies
------------------------
Production of Runof_f Time Seri�s
Project Location : Sea-Tac
Computing Series : 25011-15minpre. tsL
Regional Scale Factor : 1 .00
Data Type : Reduced
Creating 15-minute Time Series cil�
Loading Time Series File:C: \KC_St�JDA4\:{C__.DATA\STTv15R..rnL .
Till Grass 0 . 04 acres
Loading Time Se��ies Fi_le:C: \1<C_S[�JDM\KC__DATA\S�Prl:l_5R ,rnf .
Impervious 0.11 acres
--------------
Total Area : 0.15 acres
Peak Discharge: 0.148 CFS at 6: 30 on Jan 9 in Year 8
Storing `.I'ime Series File: 15011-1.5rn? npr_-e. lsf .
Time Series Compuled
ICCRTS Command
Enter the Analysis TOOLS I��lodule
Analysis 'i'ools Commard
Compute PEAKS and Flow Fre�:Gr_cies
----------------------------------
Loading SLage/Discharge curve:15011-15minpre. tsf .
Flow Frequency Analysis
--------------------------------------------------------
Time Series I'i1e: 15011-15minpre. tsf
Project Location:Sea-Tac
rrequencies & �eaks sa-.�ed to �i�e: "_`_i::1._-�timi_n��re.pks .
Analys i s Too�s C'or.unand
----------------------
RETURN to Previous Menu
-----------------------
KCRTS Command
CRF:ATE a new Time Series
------------------------
Production of Runoff Time Series
Project Location : Sea-Tac
Computing Series : 15011-15minde��. tsf
Regional Scale Factor : 1.00
Data Type : Reduced
Creating 15-minute Time Series File
Loading Time Series File:C: \I<C_SWDIK\KC_DATA\S`1'TG15R. rnf .
Till Grass O.U1 acres
Loading Time Series Tile:C: \ICC_SWDP�!\I:C_DATA\STEI15h. rnf .
Impervious 0.14 acres
--------------
Total Area : 0. 15 acres
Peak Dischar.ge: 0 .165 CFS al 6: 30 on �an 9 �i� Year 8
Storing Time Series Fi1�� : 1=�01_i-15mir.dev. ts£ .
Time Series Computed
KCRTS C�mmand
Enter the Analysis TOOLS Mcdule
---------------------------
Analysis 'I'ools Command
----------------------
Compute PE:FIKS and Flow Frequencies
----------------------------------
Loadiny Stage/Discharge curve : �L50L1 -15mi_r.dev . lsf .
I'1ow Frequency Analysis
------------------------------------- ---------- ---
Time Series File: 15011-15mindev. �sC
Project Location:Sea-Tac
Frequencies & Peaks saved to �ile: l�Cil1- l.�m.indev .pks .
Analyszs Tools Command
RETURN to Previous N'enu
-----------------------
KCRTS Command
eXit KCRTS Program
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rlow r^requer_cy Analysis
�ime Series File:15011pre. tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis-------
I'low Rate Rank Time of �eak - - Peaks - - Rank Return P.rob
(CFS) (CL'S) Period
0 .030 6 2/09/O1 2 :00 0.060 1 100.40 0.990 '
0.025 8 1/05/02 16:00 0. 041 2 25.00 0 .960 '
0.036 3 12/08/02 18:00 0.036 3 10.00 0 .900 ,
0.028 7 8/26/04 2:00 0.034 4 5 .00 0.800 '
0.034 4 10/28/04 16: 00 O. d32 5 3 .00 0.667
0 .032 5 1/18/06 16: 00 0. 030 0' 2 .00 0 .500
0 .041 2 10/26/06 0: 00 0.028 7 1.30 0 .231
0.060 1 1/09/08 6:00 0. 025 8 1 .10 0 . 091
Computed Peaks 0. 053 50 .00 0 . 980
Flow Frequency Analysis
Time Series File:15011dev. tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis-------
i Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS} Period
0 .034 6 2/09/01 2:00 0. 067 1 100.00 0.990
0 .029 8 1/05102 16:00 0. 050 2 25 .00 U . 960
0 .041 3 12/08/02 18:00 0.041 3 1.0.00 0 .900
0 . 034 7 8/26/04 2:00 0 . 040 4 5.00 0 .800
0.040 4 10/28/04 16:00 0.036 5 3 .00 0 . 667
0.036 5 1/18/06 16:00 0.034 6 2 .00 0. 500
0 .050 2 10/26/06 0:00 0.034 7 1. 30 0 .231
0 .067 1 1/09/08 6:00 0.029 8 1 .10 0 . 091
Com�uted Peaks 0 . 051 50 . 00 0 . 980
I
Flow �requency Analysis
Time Series Fi1e:15011-15minpre. tsf
1'roject Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Fr.equency Analysis-------
Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) {CFS) Period
0 . 052 6 8/27/01 18:00 0. 148 1 100.00 0 .990
0.037 8 9/17/02 17:45 0.107 2 25.00 0 .960
0 .107 2 12/08/02 17:15 0.072 3 10.00 0 .900
� 0 .042 7 8/23/04 �14: 30 0.061 4 S.OQ 0 .800
0 .058 5 10/28/04 16: OQ 0.058 5 3.00 0 . 667
0 .061 4 10/27/05 10:45 0.052 6 2 .00 0 .500
0 .072 3 10/25/06 22:45 0.042 7 1 .30 0 .231
0 . 148 1 1/09/08 6:30 0. 037 8 1.10 0.091
Computed Peaks 0 . 135 50. 00 0 . 980
Flow Frequency Analysis
Time Series File:15011-15mindev. tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis---- --
1�low Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS) Yeriod
0 .065 6 8/27/O1 18:00 0. 166 1 100.00 0. 990
0 . 045 8 9/17/02 17:45 0. 124 2 25. 00 0 .960
0 . 124 2 12/08/02 17:15 0. 088 3 10_00 0 .900
0 . 052 7 S/23104 14:30 0. 073 4 5.00 0 .800
0 .069 5 10/28/04 16:00 0.069 5 3.00 0 .667
0 . 073 4 10/27/05 10:45 0 . 065 6 2 . 00 0. 500
0 .088 3 10/25/06 22:45 0. 052 7 1. 30 0.231
0 . 166 1 1/09/08 6:30 0. 045 8 1. 10 0 . 091
Computed Peaks 0 . 152 50. 00 0 . 980
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APPENDIX B
TECHNICAL INFORMATION REPORT DATED
J U LY 6, 2007
TECHNICAL INFORMATION REPORT
Proposed Harper Engineering Building and Parking Lot
NWC - S.W. 7th Street and Seneca Avenue S.W.
Renton, Washington
Prepared for:
Harper Engineering Co.
206 South Tobin Street
Renton, WA 98055
,i
July 6, 2007
- Our Job No. 12948
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, � - 15215 72ND AVENUE SOUTH KENT,WA 98032 (425)251-6222 (425)251-8782 FAx
o z BRANCH OFFICES ♦ OLYMPIA,WA ♦ TACOMA,WA ♦ SACRAMENTO,CA ♦ TEMECULA,CA �
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1.0 INTRODUCTION/GENERAL INFORMATION
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1.0 INTRODUCTION/GENERAL INFORMATION
The proposed project site is approximately 2.21 acres in size located on the northwest corner of
S.W. 7th Street and Seneca Avenue S.W. within the City of Renton. More particularly, the site is
located within a portion of the Southwest quarter of Section 18, Township 23 North, Range 5
East, Willamette Meridia�i,City of Renton,Washington.
The site is fairl�� triangular in shape with a large curving side located along the northern property
line of the site, which is adjacent to a railroad right-of-��ray. S.W. 7th Street forms the project
site's southe�n boundary and there is an existing development located east of the project site. This
is a redevelopment project cur-�-ently consisting of parking lot and landscaping areas. The
proposal for this development is to modify the parking lot to construct a ne�v building for the
proposed Haiper Engineering manufacturing and office space located in the central portion of the
project site. Portions of the parking lot will remain intact and portions of the parl:ing lot will be
replaced with new parking lot surfacing. The total area of impervious surface subject to vehicular
traffic will tx; substantially reduced ���ith this project. There is already an existinb conveyance
syste�n located on the site that routes all stormwater runoff into a detention vault sized in
accordance with the 1990 King County, Washington Surface Water Design Manual (KCSWDM)
in March of 2001. Please refer to the grading and drainage pla» located on the next page of this �
report for an explanation of how the site will be configured under the new developed conditions.
Since this project site is not increasing the amount of impervious surface by more than
5,000 square feet, and since it is also decreasing the amount of impervious surface subject to
vehicular traffic, there are. no modifications proposed to the deten�ion vault located in the centei-
portion of the project site, which discharges into S.W. 7th Street. As mentioned previously>
minor modifications will be made to the conveyance system and, since catch basins are being
added, the conveyance system will ]ikely be more than sufficient to convey runoff from the
project site to the existing conveyance system since all pipes are proposed to be 12-inch. The
Technical Information Report for the original parking lot development is attached herewith in
Appendix A. Please refer to that document for how the on-site facilities ���ere sized for this
project. The total increase in impervious surface� �viti� tllis projcct is 3,5G3 square
1�eet = O.OS acre.
129-}8.00l.do�
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GRADING AND STORM DRAINAGE PLAN
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TECHNICAL INFORMATION REPORT
Puget Sound Electrical
Apprenticeship and Training Program
Renton, Washington
March 19, 2001
Our Job No. 7976
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CIVIL ENGINEERiNG, LAND PWJNING, SURVEYING, ENVlRONMENTAL SERVICES
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TABLE OF CONTENTS
I. PROJECT OVERVIEVV
A. Technical Information Report Worksheet
II. PRELIMINARY CONDITIONS SUMMARY
III, OFF-SITE ANALYSIS
A. Upstream Drainage Analysis
B. Downstream Drainage Analysis
IV. DETENTION VAULT ANALYSIS AND DESIGN
A. Detention Vault Calculations
B. Pre-Developed and Post-Developed Basin Area Maps
C. Wet Vau(E Calculations
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
A. Piped Conveyance Calculations
B. Conveyance Area Map
C. Miscellaneous Conveyance Calculations for Overflow Spillways, Stand Pipes,etc.
VI. SPECIAL REPORTS AND STUDIES
VII. BASIN AND COMMUNITY PLAN AREAS
VIII. OTHER PERMITS
IX. EROSION/SEDIMENTATION C�NTROL DESIGN
X. ADDITIONAL DOCUMENTS
A. Retention/Detention Facility Summary Sheet and Sketch '
XI. MAINTENANCE AND OPERATIONS MANUAL
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I. PROJECT OVERVIEW '
The proposed project is located in the southwest quarter of Section 18,Township 23 North,Range 5 East, '�
Willamette Meridian,within the city of Renton,Washington. More specifically,the site is located along '
S.W, 7th Street near the intersection with Thomas Avenue. The site is approximately 2.21 acres in size,
and is triangular in shape with approximately 260 feet of frontage along S.W. 7th Street. The site is
generally flat,sloping gently toward the north comer. The site is bounded along the north and west sides
by existing Burlington Northern Railroad right-of-way. Tlie existuig vegetation on site consists of brush
and low growing ground cover. The site is curtently not being used,and contains no existing structures.
The proposal for this parcel of land is to construct a new parking lot contaitung 200 parking stalls. This
parking lot will be used by an adjacent building that is being expanded and is reqniring additional
parking. The stormwater nuioff created from this patking lot addition will be handled using a piped
conveyance system Once stormwater enters tlus conveya2ice system, it will then be conveyed to a
detention vault that is locateci on site. This underground vault will ptovide water quality and detention,
, releasing the stormwater at pre-developed rates. Please see Section IV of tlus report for fiu�ther details
regarding the storm system and calculations.
7976.003[DED/mm/knj
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A. TECHNICAL INFORMATION REPORT WORKSHEET
King County Department of Devetopment and Environmental Services
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Fart 1 FRO:JECT OINNER AND Part 2 PROJECT L(3CAT14N A�ib , : :
PROJECT ENGINEER D�SCRiP�ION
1. _
Project Owner Puqet Sound Electrical Project Name Puqet Sound Electrical
Apprenticeship and Traininq Trust Apprenticeship and Traininq Trust
Address 5700-6th Avenue South. Suite 200 Location
Seattle, WA 98108 _ Township 23N
Phone (206) 763-7755 Range 5E
Project Engineer Hal P. Grubb, P.E. Section 18
Company Barqhausen Consulting Enqineers, Inc. Project Size 2.1 acres
Address/Phone 18215-72nd Avenue South
Kent, Washinqton 98032 Upstream Drainage Basin Size 0 acres
(425) 251-6222
Part 3 TYPE OF PERMIT Part 4 OTHER REVlEWS AND PERMITS
APPLICATION
❑ Subdivision HPA 0 DFW HPA ❑ Shoreline Management
❑ Short Subdivision ❑ COE 404 ❑ Rockery
■ Grading ❑ DOE Dam Safety ■ Structural Vaults
❑ Commercial ❑ FEMA Floodplain ❑ Other
❑ Other ❑ COE Wetlands
Part 5 SITE COMMUNITY AND DRAINAGE BASIN
Community
Green River Valley
Drainage Basin
Green River
7976.003 [DED/nun/kn)
-Parf 6 SITE CHARACTERISTICS - -
0 River 0 Floodplain
❑ Stream ❑ Wetlands
❑ Criticai Stream Reach ❑ Seeps/Springs
■ Depressions ❑ High Groundwater Table
❑ Lake ❑ Groundwater Recharge
❑ Steep Slopes ❑ Other
Part 7 SOILS
Soil Type Slopes Erosion Potential Erosive Velocities
❑ Additional Sheets Attached I�
Part 8 DEVELOPMENT LIMITATIONS �
REFERENCE LIMITATION/SITE CONSTRAINT '
❑
0
❑
❑
❑Additional Sheets Attached
Part 9 ESC REQUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION AFTER CONSTRUCTION
❑ Sedimentation Facilities ■ Stabilize Exposed Surface
■ Stabilized construction Entrance ■ Remove and Restore Temporary ESC
■ Perimeter Runoff control Facilities
❑ Clearing and Grading Restrictions ■ Clean and Remove all Silt and Debris
■ Cover Practices ■ Ensure Operation of Permanent Facilities
■ Construction Sequence ❑ Flag Limits of SAO and open space
0 Other preservation areas
❑ Other
7976.003(llGD/irun/}:n]
Part 10 SURFACE WATER SYSTE(�1°: - � - � ; �`--�
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❑ Grass Lined Channel ❑ Tank ❑ Infiltration Method of Analysis
■ Pipe System � Vault ❑ Depression SBUH
Compensation/Mitigation
❑ Open Channel ❑ Energy Dissipater ❑ Flow Dispersal of Eliminated S+te Storage
�l Dry Pond ❑ Wetland ❑ Waiver
■ Wet Vault ❑ Stream ❑ Regional
Detention
Brief Description of System Operation Stormwater controlled bv catch basins and conveved via pipes
to underground vault for detention and water qualitv.
Facility Related Site Limitations
Reference Facility Limitation
Part 11 STRUCTURAL ANALYSIS Pa►t 12 EASEMENTSTfRACTS
❑ Cast in Place Vault ❑ Drainage Easement
❑ Retaining Wall ❑ Access Easement
❑ Rockery>4' High ❑ Native Growth Protection Easement
❑ Structural on Steep Slope ❑ Tract
❑ Other ❑ Other
Part 13 SIGNATURE OF PROFESSIONAL ENGINEER
I or a civil engineer under by supervision have visited the site. Actual site conditions as observed were
incorporated into this wortcsheet and the attachments. To the best of my knowledge the information
provided here is curatg.
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Signed/Date
7976.003[D�D/nui�Jkn]
II. PRELIMINARY CONDITIONS SUMMARY
1
II. PRELIAZINARY CONDITIONS SUMIVIARY
There are no conditions for this project.
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lII. OFF-SITE Al\�i�L 1��7Z5
A. UPSTREAM DRAI�,'AGE ANALI'SIS
� The e?cistuig topography around�e site is such that the.site rece.ives ��ery litUe upstream drairiage.
As pret�iously mentioned, the site is bowided on the north and west sides by a�i existing railroad,
«rhich sits higher in elevation than the subject property. Ho«�ever, there is only a small aniouiil
of area bet«-een the site and the e�stuig railroad tracks that actually drai�is onto the subjecz
property. The adjacent parcel to tve east is currently developed and contauis all stormwater runofi,
with the exception of a small poilion at tl�e north side along the existing railroad tracks. Alono thz.
south side of the subject property is S.R'. 7th Street, �vhich is developed ancl has storu�draiiia��e
srstem that contains all stormwater runoff.
B. D01��`NSTREAl1t DRAINAGE ANALYSIS
The existing topograpl�y of the site is such t}�at tl�ei-e i�no do�vnstresni drairiage systeiii. Cun-ently,
the storm«�ater appears to infiltrate on site. If t�ie stormwater ���as Yo pond on site, it ���ould
eventually overflow ai lhe southwest corner of the site (wl�ich is the lowesc elevation alon�� the
bound�-y)into the existing storm system in S.W. 7th Avenue.
Stormwaier that is collected ori site will be detained and treated prior Co be�ing rele�ase.d u�to ali
existuig 60-inch concrete storcn line witlun S.W. 7th Streec. We are currently ui the process of
obtauulig specific irifonnation about this downst�ream system. Once this informatio�i is available,
it«�ill be includc:d���itlun this report.
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IV. DETENTION VAULT ANALYSIS AND DESIGN ��
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I�'. DETENTION �'AULT:�NAL��SIS AND DESIGl\' I
Storm drainage that «�ill be produced by the new p�u-I:ing lot �yill be controlled and conveyed via
' under�round pipes to an underground de[ention vault located on site adjacent to S.W. 7th Street. This '
under�round vault will pro�-ide the required �c�ater quality treatment and detention. More specifically, '
this system has been sized usvig the 1990 King County Surface V4'ater Design Manual. The enclosed
calculations show that the system has been desigtied to detain the 2-year post-deveioped storm while
' releasuig the 2-year pre-developed storm,and ta detav�the 10-year post-developecl storm��c�lule releasuig '
the 10-}'ear pre-developecl storm, along with a volume vicre�.se of 30 percent. Calculations have also '
been provided to verify tliat ihe 104-year post-developed storm event will be adequately con��eyed
through the proposed system. ,
The wacer quality portion of t}us vault l�as also been sized usi�ig the satne inanuaL The proposed project
will create greater than 1 acre of ne��s-iiiipervious area subject to velucular trafiic. Typically, a hioswale
along with a«�et po�id is required;however,witli t$e proposed layout,a bioswale is�iot feasible. VVe are
proposing aii inerease.in tl}e«�et pool volutne to compeli;ate for not providi�ig a bioswale. This i�icrease
is 1.5 times the required volume. We had a sitnilar situation on a recent City of Rento�i project that�;�as
approved. Please see the eiiclosed caiculations for furiher details.
Based on U_S. Department of AgricuIture u�aps,the soils classification for tius site is ��'o (Woodinville
silt loam). For tlie drainage caIculations, this converts to a hydrologic group "D."
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DETENTION VAULT CALCS
FILE No_ 7976-VLT
BAS IN SUNlMARY
BASIN ID: Al NAME: 2YR PRE-DEV
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 .21 Acres BASEFLOWS: 0 . 00 cfs
RAINFALL TYPE. . . . : KC24HR PERV IMP
PRECIPITATION. . _ . : 2 . 00 inches AREA. . : 2 . 21 Acres 0 . 00 Acres
TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 0 . 00
TC. . . . . 64 . 39 min 0 . 00 min
ABSTRACTION COEFF: 0 .20
TcReach - Sheet L: 300 . 00 ns : 0 . 2400 p2yr: 2 . 00 s : 0 . 0079
TcReach - Shallow L: 80 . 00 ks : 11 . 00 s : 0 . 0079
PEAK RATE: 0 . 19 cfs VOL: 0 . 16 Ac-ft TIME: 500 min
BASIN ID: A2 NAME: lOYR PRE-DEV
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 . 21 Acres BASEFLOWS : 0 . 00 cfs
RAINFALL TYPE . . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 2 . 90 inches AREA. . : 2 .21 Acres 0 _ 00 Acres
TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 0 . 00
TC. . . . : 64 . 39 min 0 . 00 min
ABSTRACTION COEFF: 0 . 20
PEAK RATE: 0 . 42 cfs VOL: 0 . 29 Ac-ft TIME: 490 min
BASIN ID: A3 NAME : 100YR PRE-DEV
SBUH METHODOLOGY
TOTAL AR.EA. . . . . . . : 2 . 21 Acres BASEFLOWS : 0 . 00 cfs
R.AINFALL TYPE. . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 3 . 90 inches AREA. . : 2 . 21 Acres 0 . 00 Acres
TIME INTERVAL_ . . . : 10 . 00 min CN. . . . : 86 . 00 0 . 00
TC . . . . : 64 .39 min 0 . 00 min
ABSTRACTION COEFF: 0 . 20
�EAK RATE : 0 . 70 cfs VOL: 0 .45 Ac-ft TIME: 490 min
BASIN ID: B1 NAME: 2YR POST-DEV
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 .21 Acres BASEFLOWS: 0 . 00 cfs
RAINFALL TYPE . . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 .42 Acres 1 . 79 Acres
TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 90 . 00 98 . 00
TC. . . . . 8 . 81 min 8 . 81 min
ABSTRACTION COEFF: 0 .20
TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0600
TcReach - Shallow L: 125 . 00 ks :27 . 00 s : 0 . 0100
TcReach - Channel L: 297 . 00 kc: 21 . 00 s : 0 . 0062
TcReach - Channel L: 90 . 00 kc : 21 . 00 s : 0 . 0239
PEAK RATE: 0 . 94 cfs VOL: 0 .30 Ac-ft TIME: 480 min
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DETENTION VAULT CALCS
FILE No. 7976-VLT
BASIN SUMMARY
BASIN ID: B2 NAME: lOYR POST-DEV
SBUH METHODOLOGY
TOTAL AREA. . _ . . . . : 2 . 21 Acres BASEFLOWS : 0 . 00 cfs
RAINFALL TYPE. . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 42 Acres 1 . 79 Acres
TIME INTERVAL. . . . : 10 , 00 min CN. . . . : 90 . 00 98 . 00
TC. . . . . 8 . 81 min 8 . 81 min
ABSTRACTION COEFF: 0 . 20
PEAK RATE: 1 . 43 cfs VOL: 0 .46 Ac-ft TIME : 480 min
BASIN ID: B3 NAME: 100YR POST-DEV
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 . 21 Acres BASEFLOWS : 0 . 00 cfs
RAINFALL TYPE. . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 42 Acres 1 . 79 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 90 . 00 98 . 00
TC. . . . . 8 . 81 min 8 . 81 min
ABSTRACTION COEFF: 0 . 20
PEAK RATE: 1 . 97 cfs VOL: 0 . 65 Ac-ft TIME: 480 min
BASIN ID: Cl NAME : 64a 2YR POST-DEV (WETVAULT)
SBUH METHODOLOGY i
TOTAL AREA. . _ . . . . : 2 .21 Acres BASEFLOWS : 0 . 00 cfs
RAINFALL TYPE . . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 0 . 67 inches AREA. . : 0 . 42 Acres 1 . 79 Acres
TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 90 . 00 98 . 00
TC. . . . : 8 . 81 min 8 . 81 min
ABSTRACTION COEFF: 0 .20
PEAK RATE: 0 . 23 cfs VOL: 0 . 08 Ac-ft TIME : 480 min
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DETENTION VAULT CALCS
FILE No. 7976-VLT
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HYDROGRAPH SUMMARY
PEAK TIME VOLUME
HYD RUNOFF OF OF Contrib
NUM RATE PEAK HYDRO Area
cfs min. cf\AcFt Acres
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1 0 . 193 500 6811 Cf 2 . 21 2�'� PR�
2 0 .417 490 12652 Cf 2 . 21 toY� PR-�
3 0 . 696 490 19702 cf 2 . 21 iooY2 P�.
4 0 . 938 480 13205 Cf 2 _ 21 LY2 RJST
5 1 . 429 480 20234 Cf 2 . 21 l0`(2 P��f
6 1 . 974 480 28132 cf 2 . 21 r�1'� POSf
7 0 . 228 480 3287 cf 2 . 21 1�'f}4 Po5'r
8 0 . 19 3 6 7 0 13 2 0 5 c f 2 . 21 ZYQ 2bu'f4,c7
9 0 . 417 540 20234 Cf 2 . 21 �U7f�ROU�
10 0 . 177 770 13205 cf 2 . 21 2Yf� �f�1-
11 0 . 343 550 20234 cf 2 . 21 ((n{L ��A'L
12 1 . 974 490 21066 cf 2 . 21 ���(�GE��
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DETENTION VAULT CALCS
FILE No. 7976-VLT
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STAGE STORAGE TABLE
RECTANGULAR VAULT ID No. 1
Description: VAULT (W/O 300)
Length: 75 . 00 ft -W dth: 18 . 00 ft . voids : 1 . 000
STAGE c----STORAGE----> STAGS <----STORAGE----> STAGE <----STORAGfi----> STAGE <----STORAGE---->
(ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-F't- {ft) --cf--- --Ac-Ft-
16.00 0.0000 0.0000 17.70 2295 0.0527 19.40 4590 0.1054 21.10 6885 0.1581
16.10 135.00 0.0031 17.80 2430 0_0558 19.50 4725 0.1085 21.20 7020 0.1612
16_20 270.00 0.0062 17.90 2565 0.0589 19.60 4860 D.1116 21.30 7155 0.1643
15.30 405.00 0.0093 18.00 2700 0.0620 19.70 4995 0.1147 21.40 7290 0.1674
16_40 540.00 0.0124 18.10 2835 0.0651 19.80 5130 0.1178 21.50 7425 0.1705
16.50 675.00 0.0155 28.20 2970 0.0682 19.50 5265 0.1209 21.60 7560 0.2736
16.60 810.OD 0.0186 18.30 3105 0.0713 20.00 5400 0.1240 21.70 7695 0.1767
16.70 945_00 0.0217 18.40 3240 0.0744 20.10 5535 0.1272 2],80 7830 0.1798
' 16.80 1080 0.0248 18.50 3375 �.0775 20.20 5670 0.1302 21.90 7965 0.1829
16.90 1215 0,0279 18.60 3510 0.0806 20.30 5805 0.1333 22.00 8100 0.1860
17.00 1350 0.0310 18.70 3645 0.0837 20.40 5940 0.1364 22.10 8235 0.1890
17.10 1485 0.0341 18.80 3780 0.0866 20.50 6075 0.1395 22.20 8370 0.1921
17.20 1620 0.0372 18.90 3915 0.0699 20.60 6210 0.1426 22.30 8505 0.1952
� 17.30 1755 0.0403 19.00 4D50 O.U93D 20.70 b345 U.1457 22.90 8640 0.1983
1�.40 1H9D 0.0434 19.10 4185 0.0961 20.80 6480 0.1488 22.50 8775 0.2014
�- 17.50 2025 0.0465 19.20 4320 0.0992 20.90 6615 0.1519
17.60 2160 0.049b 19.30 4455 0.1023 21.00 6750 0.1550
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DETENTION VAULT CALCS
FILE No. 7976-VLT
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STAGE STORAGE TABLE
RECTANGULAR VAULT ID No. 2
Description: VAULT (W/ 30a)
Length: 98 . 00 ft. width: 18 . 00 ft . voids : 1 _ 000
STAGE <---STORAGfi----> STAGE <----STORAGE----> STAGfi <---STORAGE----> STAGfi <---STORAGfi---->
(ft) ---cf--- --Ac-F't- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- ��
16.00 0.0000 D.0000 17.20 2117 O.D486 18.40 4234 0.0972 19.60 6350 0.1458
16.10 176.40 0.0040 17.30 2293 0.0526 18.50 4410 D.1012 I9.70 6527 0.1498
16.20 352.80 0.0081 17.40 247D 0.0567 28.60 456G 0.1053 19.80 6703 0.1539
16.30 529.20 D.0121 17.50 2646 O.OG07 1H.70 4763 0.1093 19.90 6880 0.1579
16.40 705.60 0.0162 17.60 2822 0.0646 19.60 4939 0.1134 20.00 7056 0.1620
16.50 682_00 0.0202 17.70 2999 0.0688 18.90 5116 0.1174 20.10 7232 0.1660
16.60 1058 0.0243 17.80 3175 0.0729 19.00 5292 0.1215 20.20 ^409 0.1701
16.70 1235 0.0283 17.90 3352 0.0769 19.10 5468 0.1255 20.30 7565 0.1741
16.80 1411 0.0324 18.00 3526 D_0810 19.20 5645 0.1296 20.40 7762 Q.1782
16.90 1588 0.0364 18.10 3709 0.0850 19.30 5821 0.1336 20.50 7938 0.1822
17.00 1764 0.0405 18.20 3861 0.0891 19.40 5998 0.13�7
?7.1D 1940 0.0445 16.30 4057 0.0931 19.50 6174 0.1417
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DETENTION VAULT CALCS
FILE No. 7976-VLT
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STAGE DISCHARGE TABLE
MULTIPLE ORIFICE ID No. 1
Description: VAULT STANDPIPE
Outlet Elev: 16 . 00 , �.
Elev: 14 . 00 ft Orifice Diameter: 2 . 0771 in. 2 ��
Elev: 18 . 80 ft Orifice 2 Diameter: 2 . 4785 in. Z��i�
STAGfi <-DISC"HIaRGE---> STAGE <--DZSCHARGE---> STAGE <--DZSCHARGE---> STAGE <--D:SCHARGE--->
(ft) ---cfs-- ------- (ft) ---efs-- ------- (ft) ---cfa-- ------- (ft) ---cfs-- -------
16.00 0.0000 17.20 0.1293 1B.40 0.1814 7.9.60 0.3713
16.10 0.0370 17.30 0.1335 18.50 0.1851 19.70 0.3834
16.20 0.0524 17.40 0.1385 18.60 0.1888 19.80 0.3949
16.30 0.0641 17.50 0.1434 18.70 0.1924 19.90 0.4061
16.40 0.0741 17.60 0.1481 18.80 0.1959 20.00 0.4168
16.50 0.0828 17.70 0.1527 18.90 0.2521 20.10 0.4271
16.60 0.0907 17.80 0.1571 19.00 0.2773 20.20 0.4372
16.70 0.0980 i7.90 0.1614 19.10 0.2975 20.30 0.4470
16.80 0.1047 I8.00 0.1656 19.20 0.3149 20.40 0.4565
16.90 0.1111 18.10 0.1697 19.30 0.3306 20.50 0.4657
17.00 0.1171 18.20 0.1737 19.40 0.3450
17.1C O.]228 iR.30 0.1776 19.50 0 35d5
4/26/Ol 12 : 48 : 44 am Shareware Release page 7
PSEA&TP
DETENTION VAULT CALCS
FILE No. 7976-VLT
STAGE DISCHARGE TABLE
RISER DISCHARGE ID No. 2
Description: 100YR RISER OVERFLOW CHECK
Riser Diameter (in) : 15 . 00 elev: 20 . 00 ft
Weir Coefficient . . . : 9 _ 739 height : 20 . 50 ft
Orif Coefficient . e _ : 3 . 782 increm: 0 . 10 ft
STT.GE <-DISCH.ARGE---> STAGE <-DISC::ARGE--> STAGH r-DISCFG�RGE--> STRGS :-DISCHARGE--->
(ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- -------
20.00 0_0000 20.10 0.3850 20.30 2.0004 20.50 4.3041
20.00 0.0000 20.20 1.OBH9 20.40 3.0797
4/26/O1 12 : 48 : 46 am Shareware Release page 9
PSEA&TP
DETENTION VAULT CALCS
FILE No. 7976-VLT
---------------------------------------------------------------------
---------------------------------------------------------------------
LEVEL POOL TABLE SUMMARY
MATCH ZNFIA'r7 -STO- -DIS- <-PET�f:-> OUTFIAh STORhGE
<------�--DfiSCRIPTION---------> (cfa) (cfs) --id- —id- <-STAGE> id (cfs) VOL (cf)
2YR ROLTPID .. ......... ........ 0.19 0.94 1 1 16.73 8 0.19 3681.15 cf
lOYR ROt1TID .................. 0.42 1.43 1 1 20.00 9 0.42 5405.69 cf
2YR FINA.L .................... 0.19 0.94 2 1 16.29 10 0.1H 4043.17 cf
lOYR FINW.. . .. . . .............. 0.42 1.43 2 1 19.39 11 0.34 5975.1B cf
100YR O.F. CHECF: . . . .......... 0.00 1.97 2 2 20.30 12 1.97 7580.64 cf
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� SOIL LEGEND
The (�rs�copJ�ol lencr n ihe �..��.ol onc o(+he so:i nome. A se<o�d eo��a� 4i�e�.
A. 6.C,D,E,a F, :�d�<o�<s.he<los: of i�ope. SYmbols..:�I.o.n o sloc< Icncr
o� ihos<ol n�a�Y�����so.�s.
SYM80L NAtdE �•
Ag8 Aldcrwood 9ro�eUy so�+dy toom,0�0 6 perce��slopes II
AgC Ald«.+ood gro�elly aondr loom,610 I$percent slopes � i�
Ag0 Alde.•.00d grovelly sondy loom, 15�0 30 pe�ceo� slopes �I
Akf A�6c.r+ood ond Kinop soils,�ery s�cep �-
A.oB Ar<nis,Aldei.,,00d.�o�eriol,0�0 6 perc<nt slopea� I
A�..0 {u<n�s,AWc�.+ood w�oiavial,6�o IS pctcen�slopcs• I
an Mer.�s.Ere*<n w.oreriul• . � ��
BcC •k3cvusi�e q�ovelly sondy locm,6�o IS percen�slopes I�I
f3�0 Beou:ite gro.�elly sondy loam, IS to 30 pertent slopes� . I
�Lf 0-0...:•c q.o.<!!;c=�:p I<.-. <O::7�Fucc:::clor� �'.
Bh Bell:.gho�nsilt loom i. �,
Ei. B�isca sil�loon. '',
8o B�.ckley silr loom �' '��
Cb Coos�ol Beoches
, 1.
Eo Ewlmo�t:itt loom
Ed Edgc.�.:ck(;ne sondy loo�w � . '.-
Ev8 Eve+cn qrovelly sendy loom,O�o S petce�t slopes .
ErC E�N�9•oreily sondy loam,5�0 15 percef+�s[opes . .
E�O E�e`eu yro.elly soody loom, 15 to 3Q percen�stopes
h
EwC E�en-Aide.wood yrovelly:a.dy looms,6�0 15 pctcen�sloces �
i:.
InA I�dio�ob boTy fMe sond,Ote4 pe�ccM slopes . .
I�C I.�d�orwk iw.wy f7ne sond,�to IS pe+ce.d slopes ..
In0 Hd:e..ob 1oo�wy ti�e aond, IS�0 30 percent alopes
Kp8 Kitsup sih loo�w,2 to 8 perce'+t:lopes � �q,.
� KpC Ki�wp sid loom,B�0 15 percent slopes ' .
` Kp0 Kiiwp sil�loow�, IS�0 30 percen�slopes � �
KsC Klovs gro.'elly(oaney wr.6,6 to 15 percent slopes
l"+..
., Mo Mi�ed ollwiol{ad ..
Ne� . N�ilton vcrr yravelly loomy swd,2 fo 1$pc�cem slopes •—
Ng Ne..bery silt lonm
' Nk Nooksock s:1�baw ""
No Norw�o so.dy Ioow. . � �- � • -.
a a�a:�a� _ ,
Os Or:d:o s:h loo�n
O+C Uroll qrovelly loes,p�o 15 pc�ce�r sbpes
' Ovp Owlf g`o•nl(y loeiw, 15 to 25 perccnt slopes
O.F p�.oll pro..elly 1oow�,AO�0 7S percene slopes .
Pc Pikhuck IooTy fine sond
P4 Pilch�rck finc sxdy.loo1n .
Rr P�yei sitty cby loo�n
. Py Pvyollvp(:.,e so..dy loom �
RoC Roq�f�ne sondy loom,a�o IS pe.ce��slopes
� Ro0 Rog.wf(:ne w..dy loom, 1$�o�S pe�cen� slopes -�
RdC Rognor-Ind�onolo ossxiot:on,stop:ng•
RdE Roq..or-��.d:o�ola ossoc:a�ion,w�odc.o�ety s�<c�•
Re HeMon s�l� IooT
1 R1+ R:�rwos�. � �
$o $olol ail�Ix.w
$h $w�rro�n�ati sil�loom
$4 Seonle wvc�.
$�n yw�cw�wc4
Y+ S�sil� loa'�. .
So ywl.o.nis�.s�l�loo... .
$r Sr�d.om�sA s�li loo.o,�h:ck zwloce.w:on�
$v $vM1o..s:t� loc... �
Tv T..4..:10.n<•.
Ur �yyon lo�c'
�},.,, r:�.,,�:�,�..�. �ro�, F.
• 71..•cw.�pos...:n oI.•�<s�. >.�.....c.�o�:ohl..1.u..�M.,.�d..--.� � -
...�I.e O��O.� .�IK] :f<n'.•,.�.e11eG..��11...n.�A ri... e.ry��1�� '
" <.�.-<.�d vse ol.Iv �:.!s.
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MAIVUAL
{2) CN values can be area weighted when they apply 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
!ow CN areas are less than 15% of the subbas;n). In this case, separate hydrographs should be
generated and summed to form one hydrograph.
FIGURE 3.5.2A HYDROLOGIC SOIL GROUP OF THE SOILS IN KING COUNTY
HYDROLOGiC HYDROLOGIC
SOIL GROUP GROUP• SOIL GROUP GROUP•
Alderwood C Orcas Peat D
Arents, Alderwood P�Aaterial C Oridia D
Arents, Everett Materiat 8 Ovall C
8eausite C Pilchuck C
Bellingham D Puget D
Briscot D Puyallup B
Buckley D Ragna� B
Coasta! Beaches Variable Renton D
Earlmont Silt Loam D Riverwash Variable
Edgewick C Salal C
Eve�ett A/B �Sammamish D
Indianola A Seattle D
Kitsap C Shacar D
Klaus C Si Silt C
Mixed Alluvial land Yariable Snohomish D
Neilton A Sultan C
Newberg B Tukwila D
Nooksack C Urban Var'iable
Normal Sandy Loam D Woodinville D �—
HYDROLOGIC SOIL GROUP CLASSIFICATIONS
A. (Low runof!potentiaf). Soils having high infiliratio� rates, even when thoroughly wetted, and consisting
chiefly of deep,welt-to-excessively drained sands or gravels. These soils have a high rate of water
transmission.
B. (Moderatety low runoff poteniial). Soils having moderate infiltration �ates when ihoroughly wetted, and
consisting chieily of moderately tine fo moderately coarse textures. These soils have a moderate rate of
v�ater transmission.
C. (Moderatefy high n�nofi potentiai). So1s having stow intiltration rates when thoroughly wetted, and
consisting chiefly o(so�s with a layer that impedes downward movement of water, or soils with moderately
fine io fine textures. These soils have a slow rate of water transmission.
D. (High runotf potential). Soils having very slow infiltration rates when thoroughly wetted aruJ consisting
chieily of clay sols with a high swelling potentiat, soifs with a permanent high water table, sols with a
hardpan or clay layer at or near the sur(ace, and shallow soifs over neariy impervious materiaL These soils
have a very sfow rate of water transmission. i
` From SCS, TR-SS, Second Edition,June 1986, Exhibit A-t. Revisions made from SCS, Soi! Inierpretation
Record, Form #�5, September 1988.
3.5_2-2 11/92 I
�
}
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TABLE 3.5.2Q SCS WESTERN VVASHINGTON RUNOFF CURVE Nll�4BERS
SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982}
Runoff curve numbers for selected agricultural, suburban and urban land use for Type 1A
rainfall distribution, 24-hour storm duration.
CURVE NUMBERS BY
HYDROLOGIC SOIL GROUP
Lf+tJD USE DESCRIPTION A B C �
Cultivated fand(1): winter condition 86 91 94 95
Mountain open areas: low growing brush and grasslands 74 82 89 92
Meadow or pasture: 65 78 85 89
Wood or forest land: undisturbed or older second growth 42 64 76 81
Wood or forest land: young second growth or brush 55 72 �� 86
Orchatd: with cover crop 81 88 y� 94
Open spaces, lawns, parks, golf courses, cemeteries,
landscaping.
good condition: grass cover on 75%
or more of the area 68 80 86 o
fair condition: grass cover on 50°�6
to 75°�6 of the area 77 85 90 92
Grave! roads and parking lots 76 85 89 91 _
Dirt roads and parking lots 72 82 87 89
Impervious surfaces, pavement, roofs, etc. 98 98 98 98
Open water bodies: lakes, wetlands, ponds, etc. 100 100 1a0 100
Single Famity Residential (2)
Dwelling Unit/Gross Acre °�6 Impervious (3) I
1.0 DU/GA 15 Separate curve number
1.5 DU/GA 20 shall be setecied
2.0 DU/GA 25 fo� pe►vious and
2.5 DU/GA 30 impervious portion .
3.0 OU/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 54
7.0 DU/GA 56 _ �
Planned unit developments, °�6 impervious
condominiums, apartmenfs, must be computed
commercial business and ,
industrial areas.
(1) For a more detailed description of agricultural land use curve numbers refer to National Engineering
Nandbook, Section 4, Hydrology, Chapter 9, August 1972.
(2) Assumes roof and driveway runoff is directed into street/storm system.
{3) The remaining pervious areas (lawn) are consfdered to be in good condition for these curve numbers.
� 3.5_2-3 , 21/92
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KING COUNTY, WAS HINGTON, S URFACE W ATER DESIGN M ANUAL
FIGURE 3.S.lE 10-YEAR 24-HOUR ISOPLUVIALS
2.7 ---- - - - -� =� — _ ---- -- - --- -- --- - -�- --
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10—YEAR 24—HOUR PRECIPITATI�N � '
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3.4�"" ISOPLUVIALS OF 10-YEAR 24-HOUR �'
TOTAL PRECIPITATION IN INCHES n,� � ' " �
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4/26/Ol 1 : 0 : 20 pm Shareware Release page 1
PSEA&TP
DETENTION VAULT CALCS
FZLE No. 7976-VLT
---------------------------------------------------------------------
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BASIN SUMMARY
BASIN ID: Cl NAME: 640 2YR POST-DEV (WETVAULT)
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 .21 Acres BASEFLOWS: 0 . 00 cfs
RAINFALL TYPE . . . . : KC24HR PERV IMP
PRECIPITATION. . . . : 0 . 67 inches AREA. . : 0 . 42 Acres 1 . 79 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 90 . 00 98 . 00
TC. . . . : 8 . 81 min 8 . 81 min
ABSTRACTION COEFF: 0 . 20
PEAK RATE: 0 .23 cfs VOL: 0 . 08 Ac-ft TIME: 480 min
�
4/26/Ol 1 : 0 : 20 pm Shareware Release page 2
PSEA&TP
DETENTION VAULT CALCS
FILE No. 7976-VLT
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HYDROGRAPH SUMMARY
PEAK TIME VOLUME
HYD RUNOFF OF OF Contrib
NUM RATE PEAK HYDRO Area
cfs min. cf\AcFt Acres
---------------------------------------------
---------------------------------------------
2 . 7 490 12&52 2 .21
3 0 . 696 2 cf 2 . 21
4 0 . 938 5 Cf 2 .21
5 . 9 480 20234 2 . 21
_-�7 0 . 228 480 3287 Cf 2 . 21 �Q 5'�+'� �T C�µ�l
9 . 540 20 2 . 21
10 0 . 177 7 3205 Cf 2 . 21
11 . 550 202 2 .21
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V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Enclosed are typical calculations necessary for sizing of the pipe facilities proposed on this project. The
rational method and Mannings formula were used for sizing purposes. Conveyance pipes have been sized
to accommodate the 100-year storm event at the flowing full condition. The intent of the pipe system
within the parking lot is to convey stormwater runoff into the detention vault. The proposed vault has
not been sized to accommodate any oft=site development.
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BARGHAUSEN CONSULTING ENGINEERS-PIPE FLOW CALCULATOR
using the Rational Method 8 Manning Formula
KING COUNTY DESIGN FOR 100 YEAR STORM
JOB NAME: NOTE:ENTER DEFAULTS AND STORM DATA BEFORE BEGINNING
JOB#: 7976 DEFAULTS C= 0.85 n= 0.012
REVISED: ##t�### d= 12 Tc= 10
A=Contributing Area(Ac) Qd=Design Flow(cfs) COEFFICIENTS FOR THE RATIONAL METHOD"Ir"-EQUATION
C=Runoff Coefficient Qf=Full Capacity Flow(cfs) STORM Ar Br
Tc=Time of Concentration(min) Vd=Velocity at Design Flow(fps) 2YR 1.58 0.58
1=Inlensity at Tc(in/hr) Vf=Velocity at Full Flow(fps) 10YR 2.44 0.64 PRECIP= 3.9
d=Diameter of Pipe(in) s=Slope of pipe(%) 25YR 2.66 0.65 Ar= 2.61
L=Length of Pipe(ft) n=Manning Roughness Coefficient SOYR 2.75 0.65 Br= 0.63
D=Water Depth at Qd(in) Tt=Travel Time at Vd(min) 100YR 2.61 0.63
FROM TO A s L d Tc n C 5UM A A`C SUM A'C I Qd Qf Qd/Qf D/d D Vf Vd Tt
CB6 C85 0.47 0.62 97 12 10.0 0.012 0.85 0.47 0.40 0.40 2.39 0.95 3.04 0.314 0.383 4.60 3.87 3.42 0.47
CB5 CB2 0.56 0.62 200 12 10.5 0.012 0.85 1.03 0.48 0.88 2.32 2.03 3.04 0.668 0.597 7.17 3.87 4.14 0.81
CB4 CB2 0.37 1.00 97 12 10.0 0.012 0.85 0.37 0.31 0.31 2.39 0.75 3.86 0.195 0.296 3.55 4.92 3.78 0.43
C83 C82 0.34 1.00 85 12 10.0 0.012 0.85 0.34 0.29 0.29 2.39 0.69 3.86 0.779 0.283 3.40 4.92 3.71 0.38
CB2 CB1 0.48 2.39 66 15 11.3 0.012 0.85 0.48 0.41 i.F39 2.21 4.17 10.81 0.386 0.431 6.46 8.82 8.25 0.13
CB1 VAULT 0.00 2.39 26 15 11.3 0.012 0.85 0.48 0.00 '1.89 2.21 4.17 10.81 0.385 0.430 6.45 8.82 8.25 0.05
VAULT EX 60" 0.00 0.50 40 15 11.3 0.012 0.85 0 0.00 1.89 2.21 4.17 4.95 0.843 0.702 10.53 4.03 4.52 0.15
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VI. SPECIAL REPORTS AND STUDIES
VI. SPECIAL REPORTS AND STUDIES
Miscellaneous reports and letters have been included for review.
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VII. BASIN AND COMMUNITY PLAN AREAS
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The project is located���ithin the Green River Drainage Basin. The communit}•plan area is called"Green
River Valley."
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; ' _ :`� ----.�� �'�.` 1 � ~` !,.� � � �,. �.,�:., ` 'r �, --`'; Figure 2
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. / .t�i. _� ,_. .-i' _ {� �: . ~1 sKo6o.i.�e F.- ♦ . r . t -ro.es _';�..1�r .
f ' V' ' ;j. J• ' �r _ i�� _.._ � � •-•_ v � u ` �-+-1 �� �/
q� L � � King County
�= � �DRAINAG `� - � f u � �C+nO/lEATTt �TF11iHED : -�-� �. ��5
� � _. _` `. :� � ; 1 "- \ry -/, 1� } � t :''1 '�`
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�-. � ,� ` �, , ` � , _, - __ .y , - .._� _,;�a Major Basin Boundary
�TRCOAIl1 -�. �;-.:1'� /� ) � `� -�—.-� •�� .
` `�i� ; _ • iwow J - �' •��--' 1 � ` � .1 �� � �
�,�, \� ,. � �� '�:�. � z �� ;� �= � �-�. = ; --�..�t- . � Sub-Basin Boundary
;�� �.: -� ---�---- 1-- �. ��- a,.., r` �,
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ii �..t '��. �• ��� �n
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c,t ✓ � ` ,.. , Source: King County Sensitive Areas
L._� ; _ � ..�...- __,�--.�_ , t �• Msp Folio,WetlsndsSupplement
, ;:-.--- �i;;t_.
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� 1:300,000
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VIII. OTHER PER11�iITS i
At this time, the pernuts anticipated for this project are as follows:
• Roadway and Drainage Construction
• Grading Peimit
7976.003(DED/mm/knj
IX. EROSIONISEDIM�NTATI4N CONTROL D�SIGN
IX. EROSION/SEDIMENTATIOIV CONTROL DESIGN
The limits of clearing have been shown on the construction plans to encompass the entire site area. Silt
fences have been shown on the plans to protect the adjacent properties from any possible sediment runoff.
Since the site is only approximately 2 acres in size, and currently infiltrates all on-site stormwater, we
do not feel that it is necessary to provide any form of sediment traps or ponds. As construction
progresses,silt fences wilt be maintained,and catch basin protection will be installed to ensure that alI ',
stonnwater leaving the site is clean and free of sediment. Once the underground detention vault is
installed,it�vill act as a sediment trap,which�vill ensure that not sediment laden water will leave the site.
7976.003[DED/mn✓kn]
i " -
i
I
X. ADDITIONAL DOCUMENTS
X. ADDITIONAL DOCUMENTS
A. RETENTION/DETENTION FACILTI'Y SUMMARY SHEETS AND SKETCHES
�976.0(13(DED/mm/F:n]
i -- - - - ---- _ . ._
KI � G COU `ITY, WASHINGTON, SURFACE WATER DESIGN MANUAL
RETENTION/DETENTION SUMMARY SHEET
Development ���a� �*� ��TTLt�A�- �PP(�f�l��.Sf-�7 P Date �� �s � D 1
� ��,�-rt�rb �2ob
Location S• ua. 1� �'`'� "T�1�S _A�'�-- --
ENGINEER � DEVELOPER
Name �� ��`'�3 Name �I U-- �'i35�-�-
Firm �A�61'fi�VS�1 Firm �PU�fDUI�t�L.�G'((t�G� A�'fl2E.r�'sl'IC£'SNP
Address ��L15 -]2tsD f�Y� S Address GJ�Uo b�fh/�S. Svl� Zo�
1�f.�'(� � `�&032 �fA'i7�k u-�Pr `"7$10�S
Phone �5 " �� �622'� - Phone �b -�b3-7�SS
• Developed�ite Z� 2 acres Number of Lois �
• Numbe�of Detention Facilities On Site �
• Deteniion provided in regional facility 0
Regional Facility bcation
• No detention required �
Acceptable receiving waters —
• Downstream Drainage Basins
Immediate Major Sasin
Basin A (}z�J ��(�,,�2
Basin B -
Basin C
Basin D �
TOTAL 1NDIVIDUAL BASIN
Drainage easin(s) � A B C D
OnsiteArea 2'Z� Z'Zl
— �-
Ofisite Area v���. v�� - .
Type of Storage Facility
Live Storage Volume � 1�3D ����
I Predeveloped Runoff Rate 2 year �'��
� _ 10 year o.5c�I
, Postdeveloped Runoff Rate 100-year �•5�$
� 2year °.qgp
j 10 year I. 519
; Developed Q 100 year 2•���
� Type of Restriction ��-
�' Size oi Orifice/Restriction
� Orifice/Restr"�ction No.1 2 ��gN -
No.2 3��g�
� No.3
� No.4
� No.S
� . �,.
XI. MAINTENANCE AND OPERATIONS MANUAL
n � �� �, � v �.� �� � Y, �vn � Fiif� l, 1 U ��, SUII I AC [: W �� TGR I> LSI <; N M �\ �] UAL.
MAlNTENANCE REQUIREMENTS FOR
PRIVATELY MAINTAffVED DRAINAGE FACILITIES
NO. 1 - PONDS
Malntenance Condltlons When Malntenance Reeutts Ezpected
Component Delect I� Neadad YJhen Melntanence Ie Perlormed
General Trash 8 L�ebris Any trash and debris which exceed 1 Trash and debris c�eared from site
cubic toot per 1000 square feet (this is
abovt equal to the amovnt ol trash it
would Iake lo fill �p one standard sixe
oflice garbage can). In general,Ihere �
should be no visual evidence of dumping.
Poisonous My poisonous vegetation which may No danger ot poisonous vegetation whe�e
Vegetat�on constitute n hazard to County personnal County perso�ne!ot the public mi9ht
or 1he public. F�camples of poisonous normaliy be. (Coordination with
vegetation include: tansy ragwoA, poison Seattle/FGng Counry Health Department)
oak, stinging nettles,devils club.
Pollution Oil,gasoline,or other contaminanis of No contami�ants present other than a
one gallon or more or any amount found surface film. (Coordination with
lhat co�ld: 1)cause damage lo pfant, Seattle/}Gng County Health Department)
animal,or mari�e life; 2) constitute a tice
haZetd;or 3) be flushed downstream
during�ain storms.
Unmowed Grass/ M tacility is located in private rosidential 1"fien mowing Is needed,grass�ground
Ground Cover ares,mowing is needed when grass cover should be mowed to 2 inches in
- exceeds 18 inches i�height. (n other height.
areas,the general policy is to make the
pond site match adjace�t ground cover
� and tarrain as long as there is no
interierence with the function oi Ihe
facility.
Rodent Fioles My evide�ce ol rodent holes if laciliiy is Rodents destroyed and dam or berm
ading as a dam or berm,or any evidenca repaired. (Coordination with Seattle/
ot water piping through dam or berm via King County liealth Depa�tment)
rodent holes. .
Insects When insects such as wasps a�d hornets Insects destroyed or removed from site.
intertere with mai�tenance activities.
Tree Growth Tree growth does�ot allow maintenance Trees do not hinder maintenance
aocess or interteres with maintenance activities. Selectively cultivate Irees such
activiy(.e.,stope mowing,silt removal, as alders tor firewood.
vacto�ing or equipment movements). H
tcees are no!i�te�tering with access,leave
t�ees alone.
Side Slopes o( Erosio� Eroded damaga over 2 inches deep Slopes should be stabilixed by using
Po�d whe�e cause of damage is stitf present o� app�opriate erosion control measure(s):
where there is potential for continued e.g.,rock rein(orcement, planting ol
erosion. grass,compaction.
Storage Area Sediment Accumulated sediment that exceeds 10% Sediment cleaned out to desig�ed pond
of the desig�ed pond depth. shape and depth; pond reseeded if
necessary to cont�ol erosio�.
n�..rt fl' c�•n.....,, •. r _ �
�kcs .^.Y P;.• _ �. . . ._.. . ,._ ......... , ..,�., �,�v��u ud uudi oack to ti�a ars�yn
i�ches lower �han t�ie design elevatio�. elevation.
Emergency F3ock Missing Only one Iayer of rock exists above native Replace rocka to dosign standards.
Ove�llow/Spillway soil in area five square feet or larger, or
any exposure ol native soil.
:.-i ij/1;
NO. 2 - INFILTRATION
Mnlnte�a�ce CondlUona When Malntenance Re�ults Expe:.�ed
Compo�ent Delect I• Needed When Mnintenanco la Petlormed
General "rash 8. Debris See 'Ponds' Standard No 1 See 'Ponds Stendard No �
Poisonous See 'Ponds' Slandard No. 1 See "Ponds Standard No. 1
Vegeta�ion
Pcliufion See'Ponds" Standard No. 1 See 'Ponds Standard No. 1
Unmowed Grass/ Sae "Ponds'Standard No. 1 Sea 'Ponds S�andard No. 7
Gre�nd C4.•er
Rodent NoSes See 'Ponds' Standard No. 1 See 'Ponds Standard No. 1
lnsects See 'Portds'Standard No. 1 See 'Ponds Standard No. i
Storage �vea Sedimont A percolation test pit or test oi lacility Sediment is removed and/or lacility is
indicatas facility is only working at 9096 ot cleaned so that inliltration system works
its desigrted capabilities. according to design.
�t�eet Cover Sheet oover Is visible a�d has more than Sheet aover repaired or replaced.
(If Applicable) three t/4-inch holes in it.
Sump Flled With Any sediment and debris filling vault to Clean oul sump to design depth.
Sedimenl and t0%of depth Irom sump boriom to
Oebris (I( boctom ot ouUet pipe or obstructing tlow
ApplicaWe) into lhe connector pipe.
Fifter Bags Ftled with Sediment and debris fill bag more than Replace filter bag or redesign system.
Sedime�t end 1/2(ull.
Debris
Rock Fite�s Sediment and By visual Inspection tittle or no water Replace gravel in rock lilter.
Debris flows through filter du�i�g heavy rain
storms.
�
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A-� � 1/� i
J
K i NG COUNl l', WASHINGTON, SUKFAC [ �'�� A I I: R l_> ESIGi�! �:lA i� �� r\ �,
NO. 3 - CLOSED DETENTION SYSTEMS (PIPES/TANKS)
Maintenance Condltlons When Malntennnce Resulta Expacted
Component Defact Is Needed When Mnlntenence la Performed
Storage Area Piuggad Air Venis One-half ot lhe cross section ol a vant is Verns tree o! debris and sediment.
blocked al any point with debris and II
sediment. I,
Oobris and h+ccumulated sediment depth exceeds A?I sediment and debns removed from II
Sed;ment 1096 oi the diameter of the storage area storage area. �
for 1/2 length o1 sto�age vault or any I
point depth exceeds 15% ol d+ameter �
Example: 72-inch storage tank would I
require cleaning when sediment reaches �,
depth oi 7 inches tof more lhan 1/2 '
fength ol tank. '
.h�ints Behveen Any crack allowing material to be Atl joints between tank/pipe sedions are
Tank/Pipe Section UanspoAed i�to facility. sealed.
Tank/Pipe Bent My part o(tank/pipe is bent out o(shape Tank/pipe repaired oc replaced to design.
Out o1 Shape more than 10%o(its design shape.
Manhote Cover�ot in Place Cove�is missing o�only partialty in place. Ma�hofe is closed.
My open manhole requires maintenance.
Locki�g Mecha�ism ca�not be opened by one Mechanism opens with proper tools.
Mechanism Not maintenance person with proper tools.
Working Bolts into frame have less than t/2 inch
of thread (may not apply to self-�ocking
lids).
Cover DitScult to One maintenance person cannot remove Cover can be removed and reinstalled by
Remove Gd after applying 80 pounds ot lift. Intent one maintenance person.
1 is to kaep oover lrom sealing off axess -
� to maintenance.
lBddar Ru�gs IGng County Safety Office and/o� laddar meets design standards and
Unsafe maintenance person judges that ladder is allows maintenance persons safe eccess.
unsafe due to missing rungs,
misalignment,r�st,or cracks.
Catch Basins Sae "Catch Basins'Standard No. 5 See 'Catch Basins'Standatd No.5
A-�
1 j`�i,
NO. 4 - CONTROL STRUCTURE/FLOW RESTRICTOR
Mainlenance Condltlons Whon Mnlntenance Results Expected
Componont Defecl ts Needed When Mai�lena�ce la Petlormad
General Trash and �ebris Distance betv+een debris build-up and All tresh and debris removed.
(Includes boriom o(or�lica plate is less than i-1/2
Sedimenl) leet.
Structural Damage Strudure is�ot secu�ely attached to Structure securely atlached to walt and
manhole wall and outlet pipe structure outlet pipe.
should support et least 1,000 pounds ol
up or down pressure.
Structure is not in upright position (allow Structure in correFt position.
up to t0%from plumb). �
Connections !o outtel pipe ate not Co��ections to outlet pipe are watertighl;
watertight and show si9ns of rust. structure repaired or replaced and works
as designed.
- Any holes—other than designed holes— Strud�re has no holes other than
in the st�ucture. designed holes.
Cleanout Gate Oamaged o� Geanout gate is not watertight or is Gate is watertight and wortcs as designed.
� Missinq missi�g.
Gate cannot be moved up and down by Gate moves up and down easily and is
o�e maintenance petson. watertight_
Chain leading to gate is missing or Chain is in place and works as designed.
demaged.
Gate is rusted over 50%ot its wriace Gnte is repaired o�replaced to meet
nrea. design standards.
�Oritice Plate Damaged or Controi device is not working prope�ly Piate is ln plaoe and works ns desig�ed.
Missing dve to missi�g,ouf ot plaoe,or bent
ori(ice plate. .
Obatructions My t�ash,debris,sediment,or ve8etation Pfate is(ree of all obstructions and worlcs
blocking Ihe plate. as designed.
Overflow Pipa Obstructions My trash or debris blocking (or having Pipe is t�ee ot all obstructions and works
the potential of b�ocking)the overtlow as designed. '
pipe.
Manhole See 'Closed Qetentio� Systems" Stenda�d Sae 'Gosed Dete�tio� Systems"Siandard
No.3. No.3.
Catch Basin See'Catch Basins'Standard No.5. See 'Catch Basins'Standa�d No.5.
!
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.A-� 1/9(1
K 1 NG C� C) U N "I 1', �VASHING "I� C) N, SURrACE �� :� TE; IZ I> ��: S [ G N i�4 AN UAL
NO. 5 - CATCH BASINS
Malntenance Condltio�i Whe� Malntenencc Results Expected
Component �efoct ie Needed When N:alntennnce la Portormed
General Tiash & Oebris Trash or debris o(more than 1/2 cub�c No trash or debris located immediately in
(Includes toot which is located immadiately in froni iro�t of catch basi� opening.
Sad�ment} ot the catch basin opening or is block�ng
capacity ol basin by more Ihan 10%.
Trash or debris (i�the.basin) that No trash or debris in the catch basin.
axceeds 1/3 the depth trom the bottom
of bas�n 10 in�ert of the lowesl pire �-•-
or oul ol Ihe basin.
T�ash o�debris in any inlet or outlet pipe Intet and oullet pipes Iree of trash or
blocking more than 1/3 of its height. debris.
Dead animals or vegetation that covld No dead animals or vegelation present
gene�ate odors that would ca�se within the catch basin.
complaints or dangerous gases (e.g.,
methane).
Oeposits ot garbage exceeding i cubic No co�dition present which would attrad '
foot in volume. or support the breeding of insects ot
rodeMs.
Structural Oamage Comer of frame extends more than 3/4 Frame is even with curb.
� to Frame and/or inch pasCcurb(ace into the street (}
Top Slab applicable�. �
Top slab has holes farger than 2 square Top slab is free ot hofes and c�acks.
i�ches or ciacks wider than 1/4 i�ch
(ntent is to maka sure all mate�ial is
running into the basin}.
Frama not sittf�g tlush on top slab,i.e., Frame is siding tlush on top slab.
separatio�o(mote than 3/4 inch oi the
trame lrom the top slab.
Cracks in Basin Gacks wider than 1/2 inch and longer Basin replaced or repaired to design
Walls/8ottom than 3 feet,any evidence o(soil paAicles standards.
antering catch basin through cracks,oc
maintenanca person judges that structure
is unsound.
Gacks wider than 1/2 inch and bnger No cracks more than t/4 inch wide at the
' than 1 foot at the joint ot a�y inlet/outlet joint ot inlet/outlet pipe.
pipe or any evidence ot soil particles
e�tering catch basin through aacks.
Senlement/ Basin has setiled more than 1 inch o�has Basin reptaced or repaired to design
f,tiisalignmont rotated mora lhan 2 inches out ol standards.
� alignment.
F�re Hazard Presence ol chemicals such as nalural No 1lammable chemicals prese�t.
gas,oil,and gasoli�e.
Vegetation Vegetation growing across and blocking No vegetatio� blocking ope�ing to basi�.
mo�e than 10%o!the basin opening.
Vegetation growing in inlet/outlet pipe No vegetation ot root growth present_
joinfs that is more than six inches tall and
ioss u�an s������nos apart.
Pollution Nonllammable chemicats o(more than No pollution present othe� than suAace
1/2 cubic(oot per three feet of basin lilm.
length.
�-S 1/9C
NO. 5 - CATCH 6ASINS (Coniinued)
f.Aalntenence CondlHona 4Vhen Malntanenco Ronutts Expocted
Component Doloct 1� N�sd�d Whan Malntenenco Is Perlormod
Catch Basin Cover (:over Not in Place Cover is missing or only par7ially in place Cs.ch basln cover is closod
My apen catch basin requiros
maintenance_
Locking Mechanism cannot be opened by one M�chanism opens with proper tools.
Nechanism Not maintenance person with proper tools.
Worki�g 8olts inlo frame have less than 1/2 inch
o!Ihread.
l;over O�tticult'o pne maintenance person cannot removo Cover can bo romoved by one
Remove lid ahet applying 80 Ibs:ot lift; intert is ma,ntenance person.
keep cover f�om sealing oN acoess to
maintenance.
Ladder Ladder Rungs Ladder is unsate due to missing rungs, Ledder meets design standards and
Unsate misalignment,�ust,cracks,or sharp aliows maintenance person sata access.
edges. -
Metal Grates Grate with openi�g wider than 7/8 inch. Grate openings meet desifln standards.
((applicabie)
Trash and Oebris Trash and debtis lhat is blocking more Grate free of trash and debris.
than 20%of grate surface.
�amaged or Grate missing or broken membor(s) cf Grate is in place and meets design
Missing the grate. standards.
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�: INC; � UI� N l l', \\' ASHINGTON, SU RI� ACE� WAl' ER DESIG N M �� NUA1.
NO. 6 - DEERIS BARRIERS (e.g, Trash Racks)
Malnlo�ance Co�dttlona Whon Malntenence Resutts Expected
Component Defect Is Needed When Malnlenence Is Per(ormed
G3neral Tissh and Dobris Trash or debtis that is plugging more IIarrior cloar to recoivo capacity flow
than 20%of the openings in the bar�ier
�.1ota: Dscioged/ ti4issing Bars are bent out of shape more ihan 3 �srs In place wilh no bends more than
F�ars inches. 3/4 inch.
Bars are missing or entire barrier is Bars in plaoe acoording to design.
missir,g.
Bars are loose and rust is causing 5096 Repair-or replaoe barrier to design
dete�ioralion to a�y part of barrier. standards.
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NO. "l - ENERGY DISSIPATORS
Mal�tonance CondlUona When MSnlntenance Re�uri• Expacted
Component Defect I� NeedeA Whan Malntenence 1� Perlormod
Ex1em01:
Roek Pad Missing or Moved Only one layer ol rock exis�s above native P.e.�ace rocks to dev��n s;andard.
Rock soil in a�ea five squara feet or largar, or
any exposure ol native soil.
D�spersion Trench Pipe Plugged with Accumulated sediment that exceeds 20% Pipo cleanod/flushotl so that it matchas
Sediment of the design deplh. des�gr.
PJot Oischareing V�sual evidence of water discharging at Trench must be redosigned or rebuilt to
Waler Propetly ooncenttated points along lrench (normal standard. `
condition is a'sheet flow'ol wnter along
trench). Intent is to prevenl erosion
damage.
Perforations Over 1/2 ot perloretions in pipe are Clean or rnpiace pe�forated pipe.
Plugged plugged with debris aird sediment.
Weter P.,ws Out Maintenance perso�observes water Facility must be rebuiit or redesigned to
Top oi'Distributo�' ftowing out during any storm less than standards.
Catch Basin the desipn storm or it is causing or
appears Iikely to cause damage.
Receiving Area Water in�eceiving area is causing or has No danger ot landslides.
Ove�-Saturated potential ot causing landslide problems.
Internal:
Manhote/Chnmber Wor�or Onmaged 5trudu�e dissipating ilow deteriotates to Heplace structure to design standards.
Posts, Battles, 1/2 or original size or any concentrated
Sides ot Chamber worn spot axcaeding ona square loot
which would make sfructure unsound.
Qther De(ects See 'Catch Basins'Standard No. 5 See 'Catch Basins' Sta�dard No. 5
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F� 1 N G C O U �1 "l� l', \V ,1 ti F i 1 N G TO N, S L? R F i� C [: �:' ;� T E f2 D E S I G N �f A N U A L
NO_ 8 - FENCING
Malntonance Condltlona When Malntenance Roaults Expected
Componen! Defoct ls Needed When Malntenance I: Pe�formad
General Missing or Broken My detect in the fenca that permits easy Parts in piace to provide adequate 'i
Parts entry to a facility. securiry. II
Perts brokan or missing. Sroken or missing parts replaced. I�
[rosion Erosfon moro than 4 fnches hiph and �2- No opening under 1he fence thal exceeds '�
i8 inches wide permiriing an opening 4 inches in height. !
under a fence.
Wira Fences Oamaged Paris Posts out o1 plumb more tha�6 inches. Posis pFumb to within i-t/2 inches.
Top rails bent more ihan 6 inches. Top rail (ree ot bends greatar lhan 1 inch
Any part ot tence (�ncluding posts,top Fence is alignod and meets deslgn
rails,and fabricJ more than t foot out o! standards.
design alignme�t.
Missing or loose tension wire. Tensio�wire in ptace and holding fabric.
Missing or toose barbed wire that is Barbed wire in place wiih less than 3/4-
saggi�g more than 2-1/2 inches between inch sag between posts.
posts,
Extension arm missi�g,broken,or bent Extension arm in place with no bends
out oi shape more lhan t-1/2 inches. laiger tha� 3/4 inch.
Deteriorated Pain1 ?a�t or patis that have a tusting or scaling Structurally adequale Qosts ot paRs with
or Protective condition that has aHectsd st�uctural _ a unitotm protective coating.
Coating adequacy.
Ope�ings in Fabric Openings in tabric ara such that an 8- No openings in fabric.
inch-diamete�ball could fit through.
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KING CO U t�' 7l . �V �: SH l NG "C (� N, SURFAC � �Vil `[� LR DLS lG f�t ;�S �� TJ U ,1 f.
NO_ 9 - GATES
Malntananco CondlUons When Maintenance Reaulis Expected
Component De(ect l� Needed When Malntenance Is Per(ormed
Genetal Oamaged o� Adissin0 gate or locking devices. Gates ana focking devices i� place.
Missing Members .
E3roken or missing hinges such that gate Hinges intact end lubed. Gete is working
cannot be easily opened and closed by a lreety.
mainlenance person. .
Gate is out o1 plumb more than 6 inches Ga1e is aligned a�d vertical.
and more than t toot oul ot design
afignment.
Missing stratcher bar,streicher bands, Stretcher bar,bands, and ties in place.
and ties.
Openings in Fabric See'Fencing' Standard rlo.8 See 'Fencing'Standard No. 8
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K ( NG C (� U � TY, \�' ASHINGTO �1, SUR }� ACE �VATGR DESIGN MANUAL
NO. 10 - CONVEYANCE SYSTEMS (Pipes & Ditches)
Malntennnce Condltlona When Melntenanca Reiults Expectad
Component Defect la Neoded When Malnfenance Is Performed
Pipes Sediment & Oebris Accumuleted sediment that exceeds 2056 Pipe cleaned of a!i sediment and debris.
of the diameter ol the pipe.
Vegetation Vegetation that reduces tree movement ot All vegetat�on removed so waler flows
waler through pipes. f�eely through pipes.
�amagod Protective coeting is damaged; rus!is Pipe repeired or replaced.
causine more than 50%dalerioration to
any part o}pipe. .
My dent thal decreases the cross section Pipe repaired or replaced.
area o}pipe by more then 20%.
Open Ditchos Trash 8 Debris Ttash and debrls exceeds t c�bic foot Trash and debris cfeared lrom ditches.
per.1,000 square feet o!ditch a�d slopes.
Sodiment Acc�rrwlefed sediment ihat exceeds 20% Oitch cleaned/flushed oi all sediment end
of the design depth. debris so that it matches design.
Vegetation Vegetation thnt roduces lree moveme�l ol Wa1er}lows troely through ditches.
water through ditches.
Eroslon Damage lo See 'Ponds' Standard No. 1 See 'Ponds'Standerd No. 1
Slopes
Rock Lining Out of MaiMe�ance person can see native soil Fieplace rocks to design standard.
Place or Missing (H beneath the rock lini�g.
Applicable)
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Catch Basins See"Catch Basins'Standard No. 5 See'Catch Basins'Standard No.S
Oebris Barriers See'Dobris Barrie�s` Standard No.6 Seo'Debris Barriers' Standard No.6
(e.g., Trash Rack)
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KING CO U NTY, �vASHINGTON, SURFACf_ WATGR DESIGN �1AN UAL
NO. 11 - GROUNDS (Landscaping)
VSal�tene�ce Condltlont When Mafntenence Resutts ExpecleA
Componant Defsct I• Needed When Malntenance I� Perlormed
IGeneral Weeds Weeds erowing in more than 20% ol the Weeds present in less than 596 of the
(Nonpoisonous) IandscapeA aren (treea and shrubs onty). landscaped area.
Safery Na:ard Any presenoe of poison ivy or other No poisonous vegetation present in a
poisonous vaeetatio�. landscaped area.
Trash or Urier Paper,can, bottles,tolalling more than 1 fvea clear of lirier.
cublc ioot within e IendscAn?A erea (trees
and shrubs o�ly)of 1,000 square leet.
Trees and Shrubs Damage Limb�or parta ol trees o�shrubs thel are Trees nnd shrubs with less than 596 0l the
split or broken which aHect more than total loliaga with split or broken limbs.
25%o(the total loliage o(the tree or
shrub.
Trees or shrubs that hnve been blown Tree o�shrub in place t�ee ot injury.
down or knocksd over.
Trees ot shrubs which are not adequately Tree or shrub in pleoe and adequately
supported ot are teaning over,causing supporiad; remove any dand or diseased
exposure o(iha roots. treas.
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i: l NG COUNTY, WASH INGTON, SU R FACE WATER DESIGN MANUAL
NO. �t2 - ACCESS ROADS/EASEMENTS
Malntenanco Conditlona When Melntenance Recultc Expected
Component Defect i• Needed When Melntenance Is Perlo►med
General Trash and Oebris Trash a�d debris exceeds 1 cubic foot Trash and debris cleared from sile.
per 1,000 square leet,i.e.,trash and
dobris would fill up one standard sizo
garbaga can.
Blocked Roadway Debris which could damage vehicle fi�es Roadway tree o(debris which could I
jglass or metal). demage tires.
My obstructions which reduce clearance Roadway overhead clear to 14 (eet high
.. abova road surlace to less tha� 14 feet. `
My obstructions restricting the access to Obstruction removed to allow al least a
a 10-l0 12-loot width tor a dfstance of 12-toot access. I
more than 12 teet or any point restricting
accesslo less than a 10-fool width.
Road Su�face Serilement, When eny su�iace defect exceeds 6 Road su�face uniformly smooth with no
Potholes, Mush inches in depth and 6 square (eet in area. evidence ot settleme�t, potho�es,mush
Spots,Ruls In general, e�y surlace defect which spots,ot ruts.
hinders or prevents maintenance aocess.
Vegetalion in Fioad Weeds growing in the road suAace lhat Road surface lree of weeds taller than 2
Su�face are moro than 6 inches tall and less than inches.
6 inches epart within a 40asquare-loot
area.
Shoulders and Erosion Damage Erosion withi� 1-foot ol the roadway more Shoulde�(ree ot erosion a�d matching
Ditches than 8 inches wide and 6 i�ches deep. the surrounding rond.
Weeds and &ush Weeds and brush ezoead 18 inches in Weeds and brush cut to 2 inches in �I
hoight or hinder maintenance access, height or cleared in ��ch a wey as to
sllow maintenance aocess.
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