HomeMy WebLinkAboutQuendall Terminals Storm Drainage Report
Quendall Terminals
Renton, Washington
Drainage Report
November 2009 | Preliminary Report
Drainage Report
November 2009
Prepared for:
CenturyPacific, LP
1201 Third Avenue, Suite 1680
Seattle, WA 98101
Prepared by:
Tom Jones
Kris Koski, EIT
KPFF Consulting Engineers
1601 Fifth Avenue, Suite 1600
Seattle, WA 98101
(206) 622-5822
KPFF Job No. 109118.10
Property Owners:
Altino Properties, Inc., and J.H. Baxter & Company
CenturyPacific, LP
Quendall Terminals i
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Table of Contents
1. Project Overview............................................................................................................................1
Project Location .............................................................................................................................. 1
Project Description.......................................................................................................................... 1
Predeveloped Site Conditions........................................................................................................ 1
Developed Site Conditions ............................................................................................................. 2
2. Conditions and Requirements Summary......................................................................................3
3. Off-Site Analysis ............................................................................................................................4
Upstream Analysis........................................................................................................................... 4
Downstream Analysis...................................................................................................................... 5
4. Flow Control and Water Quality Facility Analysis and Design.......................................................5
Flow Control..................................................................................................................................... 5
Water Quality................................................................................................................................... 5
5. Conveyance System Analysis and Design ....................................................................................5
6. Special Reports and Studies.........................................................................................................6
7. Other Permits................................................................................................................................6
8. Erosion and Sedimentation Control (ESC) Analysis and Design..................................................6
9. Bond Quantities, Facility Summaries, and Declaration of Covenant...........................................7
10. Operations and Maintenance Manual..........................................................................................7
CenturyPacific, LP
Quendall Terminals iii
CenturyPacific, LP
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List of Tables
2-1 Conditions and Requirements Summary.......................................................................................3
Appendices
Appendix A – Site and Project Information
Figure 1A: Project Location
Figure 2A: Existing Site Conditions
Figure 3A: Proposed Site Conditions
Figure 4A: NRCS Soils Map
Figure 5A: FEMA Flood Insurance Rate Map
Figure 6A: TIR Worksheet
Appendix B – Calculations and Proposed Strom Drainage System
Figure 1B: Conceptual Storm Drainage Plan
Figure 2B: Isopluvial Maps (2-Year, 25-Year, 100-Year, and Annual Runoff)
Figure 3B: Conveyance Calculations
Figure 4B: Water Quality Calculations
Figure 5B: StormFilter Product Information
1. Project Overview
This Technical Information Report (TIR) addresses the conceptual design of the storm drainage
conveyance and water quality facilities for Quendall Terminals Master Site Plan entitlement. Site
drainage will be conveyed to on-site water quality treatment facilities prior to discharge to Lake
Washington. See Figure 6A (Appendix A) for the TIR Worksheet.
PROJECT LOCATION
The Quendall Terminals project is located at 4350 Lake Washington Boulevard North within the City of
Renton in King County, Washington. The project is located west of Ripley Lane North and northwest of
the intersection of Lake Washington Boulevard North and Ripley Lane North. The project is located in
a portion of Section 29, Township 24 N, Range 5 E, W.M. See Figure 1A in Appendix A for the project
location.
An additional parcel located east of the main project site across Ripley Lane North is included in
project planning considerations but is not part of this drainage report. No improvements are planned
for this additional parcel.
PROJECT DESCRIPTION
Quendall Terminals is a proposed mixed-use development including five stories of residential or office
space above two levels of above-grade parking or retail and restaurant space. The development
project anticipates entitlement of the following:
Residential 800 Units
Office 245,000 Square Feet
Retail 21,600 Square Feet
Restaurant 9,000 Square Feet
Parking 2,215 Spaces
PREDEVELOPED SITE CONDITIONS
The existing site is vacant and is under the direction of the Environmental Protection Agency (EPA).
The site is partially vegetated with areas of grass, shrubs, brush, and trees where the site has been
undisturbed for an extended amount of time. Other areas used more recently contain bare soil and
debris from log yard operations. Debris piles from log yard operations are located on the site. The site
is contaminated with hazardous substances as a result of past industrial uses, including a creosote
processing facility.
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Quendall Terminals 1
The main site is approximately 20.3 acres in size with approximately 1,583 feet of shoreline along
Lake Washington. Site slopes are generally 0 to 5 percent with localized slopes up to 2H:1V at debris
piles and up to 1H:1V at the bank of the lake. The site slopes gradually from east to west. Wetlands
are located along and near the lakeshore on the west side of the site. There are approximately
34,959 square feet of existing wetlands on the site.
The parcel east of the main project site and Ripley Lane North is approximately 1.2 acres in size and is
not part of this drainage report. No improvements are planned for the east parcel.
Manmade stormwater conveyance, water quality, and detention facilities on the site consist of swales
and berms constructed in accordance with the Quendall Terminals Interim Stormwater Management
Plan (Aspect, October 2008) in conjunction with a previously existing small sediment pond
(approximately 1,722 square feet including rock check dams). The purpose of the Interim Stormwater
Management Plan is to control site runoff and erosion prior to future environmental mitigation.
Surface runoff currently infiltrates or is conveyed to Lake Washington via surface flow or swales. There
are no creeks or streams located on the site. See Figure 2A in Appendix A for existing conditions.
The Natural Resources Conservation Service (NRCS) Soils Map indicates that the site is underlain with
Norma sandy loam and Bellingham silty loam. See Figure 4A in Appendix A. The site does not lie
within a 100-year floodplain per Federal Emergency Management Act (FEMA) Flood Insurance Rate
Map. See Figure 5A in Appendix A.
DEVELOPED SITE CONDITIONS
The proposed site improvements include a mixed-use development consisting of residential, office,
retail, restaurant, and parking spaces. Proposed site slopes are anticipated to be 3:1
(horizontal:vertical) or less. Piped storm drainage systems will collect and convey surface runoff from
pollution-generating surfaces to water quality treatment facilities then to outfalls at Lake Washington.
Treated stormwater will discharge to Lake Washington during normal flows. During high flows that
exceed the capacity of the water quality treatment facilities, stormwater will bypass the water quality
facilities, discharging directly to the lake.
To the greatest extent possible, roof drainage will be conveyed directly to Lake Washington, bypassing
water quality treatment facilities, via dedicated storm drainage systems for non-pollution-generating
surfaces.
Surface water collection, conveyance, and treatment will be maintained separately from any
groundwater activity.
Prior to this development, a site remediation/mitigation plan will be executed under the direction of
the EPA to prevent the exposure and spread of hazardous substances to humans and the surrounding
environment. Proposed measures to prevent environmental health hazards include minimal
disturbance to contaminated soils and capping of the site.
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2. Conditions and Requirements
Summary
This report supports City of Renton entitlement processing for Master Site Plan Approval. This report is
intended to be amended in conjunction with future construction documents. Future report
amendments will be in accordance with the 2009 King County Surface Water Design Manual
(KCSWDM).
The 2009 KCSWDM outlines eight core requirements and five special requirements that must be
addressed. A summary of the requirements is shown in Table 2-1. The table shows which
requirements are applicable to this project and where requirements are addressed within this report.
Table 2-1: Conditions and Requirements Summary
Conditions and Requirements Summary See Section
Core Requirement No. 1 Discharge at the Natural Location Required 2
Core Requirement No. 2 Off-Site Analysis Required 3
Core Requirement No. 3 Flow Control Exempt 4
Core Requirement No. 4 Conveyance System Required 5
Core Requirement No. 5 Erosion and Sediment Control Required 8
Core Requirement No. 6 Maintenance and Operations N/A 10
Core Requirement No. 7 Financial Guarantees and Liability N/A 9
Core Requirement No. 8 Water Quality Required 4
Special Requirement No. 1 Other Adopted Area-Specific Requirements N/A 2
Special Requirement No. 2 Flood Hazard Area Delineation N/A 2
Special Requirement No. 3 Flood Protection Facilities N/A 2
Special Requirement No. 4 Source Control Required 2
Special Requirement No. 5 Oil Control N/A 2
CenturyPacific, LP
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Core and Special Requirements not addressed below are discussed in other sections of this report.
Table 2-1 provides a summary of the requirements and where they are addressed within this report.
Core Requirement No. 1: Discharge at the Natural Location
Stormwater runoff from the existing site either infiltrates or is conveyed to Lake Washington via surface
flow or swales. Stormwater runoff from the proposed improvements will be collected and conveyed by
a piped stormwater system to new outfalls at Lake Washington. Runoff from the existing and proposed
sites both discharge to Lake Washington. See the “Existing Site Conditions” and “Proposed Site
Conditions” exhibits in Figures 2A and 3A, Appendix A.
Special Requirement No. 1: Other Adopted Area-Specific Requirements
Does not apply. The proposed project is not in a Critical Drainage Area or in an area included in an
adopted master drainage plan, basin plan, salmon conservation plan, stormwater compliance plan,
flood hazard reduction plan, lake management plan, or shared facility drainage plan.
Special Requirement No. 2: Flood Hazard Area Delineation
Does not apply. The proposed project does not contain and is not adjacent to a flood hazard area.
Special Requirement No. 3: Flood Protection Facilities
Does not apply. The proposed project does not rely on existing flood protection facilities or construct a
new flood protection facility.
Special Requirement No. 4: Source Control
The proposed project will require a commercial building and commercial site development permit;
therefore, water quality source controls will be implemented in accordance with the King County
Stormwater Pollution Prevention Manual.
Special Requirement No. 5: Oil Control
Does not apply. None of the proposed land uses generate average daily traffic of 100 or more vehicles
per 1,000 square feet of gross building area.
3. Off-Site Analysis
A Level 1 qualitative off-site analysis is required per Core Requirement No. 2. The off-site analysis
assesses potential off-site drainage and water quality impacts associated with development of the
project site, and proposes appropriate mitigation of the impacts, if necessary.
UPSTREAM ANALYSIS
There is no upstream tributary area contributing to site stormwater runoff.
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4 Quendall Terminals
DOWNSTREAM ANALYSIS
Runoff from the proposed site will be collected and conveyed via a piped storm drainage system and
discharge to Lake Washington. The water level in Lake Washington is maintained at the Hiram M.
Chittenden Locks. Outfalls at the lake will require armoring to prevent erosion.
4. Flow Control and Water Quality
Facility Analysis and Design
FLOW CONTROL
The project is exempt from flow control requirements by the “direct discharge exemption” as defined in
Section 1.2.3.1 of the 2009 KCSWDM. The project will feature a piped conveyance system of
adequate capacity that discharges directly to Lake Washington.
WATER QUALITY
Runoff from pollution-generating surfaces will be collected and conveyed to water quality treatment
facilities for treatment prior to discharge to Lake Washington. A water quality design flow of 60
percent of the developed 2-year peak flow rate will be used in accordance with the 2009 KCSWDM.
The water quality treatment facilities will discharge to Lake Washington. Flows greater than the water
quality design flow rate will bypass the water quality facilities and discharge directly to Lake
Washington. See Figure 4B for water quality calculations, Figure 1B for the water quality facility layout,
and Figure 5B for StormFilter product information, Appendix B.
5. Conveyance System Analysis and
Design
The proposed conveyance system will be designed to convey and contain (at minimum) the 25-year
peak flow, assuming developed conditions for on-site tributary areas. Potential overflow from a 100-
year runoff event is not anticipated to create or aggravate a severe flooding problem or severe erosion
problem. There is no upstream tributary area draining to the site or the proposed storm drainage
system. Outfalls at the discharge points of the stormwater systems will be designed to prevent
erosion.
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The conveyance system design is based on the following assumptions:
The peak flows used to design the conveyance system were calculated using the Rational Method.
Runoff coefficients (“C” values) for the Rational Method are based on Table 3.2.1.A in the
KCSWDM:
• C=0.90 for impervious surfaces, roofs, and paving.
• C=0.25 for pervious surfaces and lawns.
The minimum time of concentration is assumed to be 6.3 minutes.
Drainage areas are based on the current site plan and grading plan.
Manning’s roughness coefficients are based on Table 4.2.1.D in the KCSWDM for PVC pipe.
A coefficient of 0.013 is used in the uniform flow analysis.
A hydrologic analysis is performed for the 25-year storm event. A precipitation amount of
3.43 inches was used based on Figure 3.1.2.C of the KCSWDM.
Twenty-five-year uniform flow calculations were performed in order to calculate design flows and to
choose preliminary pipe sizes.
The minimum full flow pipe velocity is 3 feet per second, per KCSWDM Figure 4.2.1.F.
This report will be amended in conjunction with future construction documents to include backwater
calculations for final storm drain design.
6. Special Reports and Studies
The following reports have been prepared as part of the Quendall Terminal’s Master Site Plan:
Geotechnical Study, Aspect Consulting, LLC
Wetland Assessment, Standard Lake Study, Habitat Data Report, and Conceptual Restoration
Plan, Anchor QEA, LLC (one document)
7. Other Permits
This report supports City of Renton entitlement processing for Master Site Plan Approval, which
includes the following permits:
Master Site Plan
Land Use
Shoreline Substantial Development
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Prior to this development, a site remediation/mitigation plan will be executed under the direction of
the EPA.
8. Erosion and Sedimentation Control
(ESC) Analysis and Design
A temporary sediment and erosion control plan designed by a professional civil engineer will be
included with the project’s construction documents (to be produced in the future) conforming to the
requirements of the 2009 KCSWDM.
9. Bond Quantities, Facility
Summaries, and Declaration of
Covenant
Bond quantities and facility summaries are not required for Master Site Plan Approval. These items
will be provided with the project’s future construction documents.
10. Operations and Maintenance
Manual
An operations and maintenance manual is not required for Master Site Plan Approval. This item will be
provided with the final project design.
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CenturyPacific, LP
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Appendix A
Site and Project Information
Figure 1A: Project Location
Figure 2A: Existing Site Conditions
Figure 3A: Proposed Site Conditions
Figure 4A: NRCS Soils Map
Figure 5A: FEMA Flood Insurance Rate Map
Figure 6A: TIR Worksheet
CenturyPacific, LP
Quendall Terminals Appendix A
KPFF Consulting Engineers 11/2009
Quendall Terminals Storm Drainage Report Figure 1A: Project Location
Ripley Ln4 4 th St
Lake Wa shington BlvdNo
Bh
559770
559770
559840
559840
559910
559910
559980
559980
560050
560050
560120
560120
560190
560190
560260
560260
560330
560330
560400
560400
560470
5604705264480 526448052645505264550526462052646205264690526469052647605264760526483052648300 200 400 600100
Feet
06012018030
Meters
47° 32' 4''122° 11' 46''47° 31' 50''122° 11' 46''47° 31' 51''
47° 32' 4''122° 12' 22''122° 12' 22''Map Scale: 1:2,070 if printed on B size (11" x 17") sheet.
Soil Map—King County Area, Washington
(Quendall Terminals)
Natural ResourcesNatural ResourcesNatural ResourcesNatural Resources
Conservation ServiceConservation ServiceConservation ServiceConservation Service
Web Soil Survey
National Cooperative Soil Survey
9/1/2009
Page 1 of 3
SITE
Figure 4A: NRCS Soils Map
Figure 4A: NRCS Soils Map
Figure 4A: NRCS Soils Map
Figure 5A: FEMA Map
ZONE X
Areas of 500-year flood; areas of 100-
year flood with average depths of less
than 1 foot or with drainage areas less
than 1 square mile; and areas
protected by levees from 100-year
floor.
QUENDALL TERMINALS
(206) 757-8899
Century Pacific, L.P.
1201 Third Ave, Suite 1680
Seattle, WA 98101
Tom Jones
KPFF Consulting Engineers
(206) 622-5822
Quendall Terminals
T29N
R5E
SW29
4350 Lake Washington Blvd
Renton, WA 98056
X Master Site Plan Entitlement
November, 2009
November, 2009
N/A
X
KPFF 11/2009
Quendall Terminals Storm Drainage Report Figure 6A: TIR Worksheet
X EPA Superfund
2009 King County Surface Water Design Manual
X
N/A for Master Site Plan
N/A
N/A
Lake Washington
Overlay Design District C
Bellingham Silt Loam
Norma Sandy Loam
0-5% typical
0-5% typical
Low
Low
X
KPFF 11/2009
Quendall Terminals Storm Drainage Report Figure 6A: TIR Worksheet
X Lake Washington
X Liquefaction
1
Direct Discharge
N/A
N/A for Master Site Plan
N/A
N/A
N/A
N/A
Entire site discharges to Lake Washington.
Not applicable for Master
Site Plan Entitlement.
Mixed-Use Residential/Office/Commercial
N/A for Master Site Plan
KPFF 11/2009
Quendall Terminals Storm Drainage Report Figure 6A: TIR Worksheet
X
X
X
X
X
X
X
X
X
X
X
X
X Presettling Vault
StormFilters
KPFF 11/2009
Quendall Terminals Storm Drainage Report Figure 6A: TIR Worksheet
X
KPFF 11/2009
Quendall Terminals Storm Drainage Report Figure 6A: TIR Worksheet
Appendix B
Calculations and Proposed Strom Drainage System
Figure 1B: Conceptual Storm Drainage Plan
Figure 2B: Isopluvial Maps (2-Year, 25-Year, 100-Year, and Annual Runoff)
Figure 3B: Conveyance Calculations
Figure 4B: Water Quality Calculations
Figure 5B: StormFilter Product Information
CenturyPacific, LP
Quendall Terminals Appendix B
QUENDALL TERMINALS SITE
P = 2.0 INCHES
Figure 2B: Isopluvial Maps
QUENDALL TERMINALS SITE
P = 3.43 INCHES
Figure 2B: Isopluvial Maps
KPFF Consulting EngineersNovember, 2009STORM DRAIN LINE #1Drainage Calculations - Conveyance Check for the 25-year Storm EventASSUMPTIONS AND CONSTANTSManning's n = 0.013 (per KCSWDM Table 4.2.1 D for PVC pipe - Uniform flow analysis)Pr = 3.43 in. (for 25-yr 24-hr event per KCSWDM Figure 3.2.1.C)ar = 2.66 (for 25-year event per KCSWDM Table 3.2.1.B)br = 0.65 (for 25-year event per KCSWDM Table 3.2.1.B) Tc = 6.3 minutes (minimum Tc)C impervious = 0.90 (per KCSWDM Table 3.2.1.A for Pavement and Roofs)C pervious = 0.25 (per KCSWDM Table 3.2.1.A for Lawns)V min. allow. = 3.0 ft/s (for Pipes, per KCSWDM Figure 4.2.1.F)V max. allow. = 5.0Layout Contributing Flow Calculations (Rational Method)Pipe Capacity Calculations Conveyance ChecksStructure NumberImpervious AreaPervious AreaArea C Tc TfTcENDi25-yrI25-yrContributing QQTotalInlet Invert ElevationOutlet Invert ElevationPipe DiameterLength SlopeVelocity, VPipe Flow Capacity, QPipe Capacity UsedVFull CheckQ Check(sf) (sf) (acres) (min) (min) (min) (in/hr/in) (in/hr) (cfs) (cfs) (inches) (feet) (%) (ft/s) (cfs) (%)Storm Drainage Area: STORM DRAIN LINE #10SW QUAD 163,373 sf 0 sf 3.75 ac 0.90 6.3 0.30 6.60 0.78 2.68 in/hr 9.03 cfs 9.03 cfs 19.60 19.37 24 in 73.0 ft 0.31% 4.02 ft/s 12.64 cfs 71.5% OK OK1-4B 4,092 sf 455 sf 0.10 ac 0.84 6.3 0.05 6.35 0.80 2.75 in/hr 0.24 cfs 0.24 cfs 26.10 25.23 8 in 20.0 ft 4.37% 7.24 ft/s 2.53 cfs 9.5% OK OK1-5B 3,864 sf 429 sf 0.10 ac 0.84 6.3 0.06 6.36 0.80 2.74 in/hr 0.23 cfs 0.23 cfs 27.20 26.60 8 in 20.0 ft 3.00% 6.00 ft/s 2.09 cfs 10.8% OK OK1-7B 4,817 sf 535 sf 0.12 ac 0.84 6.3 0.10 6.40 0.80 2.73 in/hr 0.28 cfs 0.28 cfs 28.60 28.42 8 in 20.0 ft 0.89% 3.27 ft/s 1.14 cfs 24.6% OK OK1-7A 6,067 sf 674 sf 0.15 ac 0.84 6.3 0.46 6.87 0.76 2.61 in/hr 0.34 cfs 0.62 cfs 28.42 27.61 8 in 91.0 ft 0.89% 3.27 ft/s 1.14 cfs 54.1% OK OK1-11 646 sf 72 sf 0.02 ac 0.84 6.3 0.19 6.49 0.79 2.71 in/hr 0.04 cfs 0.04 cfs 29.30 28.92 8 in 39.0 ft 0.97% 3.40 ft/s 1.19 cfs 3.1% OK OK1-10 6,971 sf 775 sf 0.18 ac 0.84 6.3 0.18 6.67 0.78 2.66 in/hr 0.39 cfs 0.43 cfs 28.92 28.58 8 in 36.0 ft 0.97% 3.40 ft/s 1.19 cfs 36.4% OK OK1-9 4,532 sf 504 sf 0.12 ac 0.84 6.3 0.11 6.41 0.79 2.73 in/hr 0.26 cfs 0.26 cfs 28.80 28.58 8 in 23.0 ft 0.97% 3.41 ft/s 1.19 cfs 22.1% OK OK1-12B 2,894 sf 322 sf 0.07 ac 0.84 6.3 0.10 6.40 0.80 2.73 in/hr 0.17 cfs 0.17 cfs 30.60 30.40 8 in 20.0 ft 1.00% 3.46 ft/s 1.21 cfs 13.9% OK OK1-12A 4,938 sf 549 sf 0.13 ac 0.84 6.3 0.76 7.15 0.74 2.54 in/hr 0.27 cfs 0.44 cfs 30.40 28.58 8 in 165.0 ft 1.11% 3.64 ft/s 1.27 cfs 34.3% OK OK1-8 0 sf 0 sf 0.00 ac 0.00 6.3 0.25 7.40 0.72 2.48 in/hr 0.00 cfs 1.13 cfs 28.58 27.61 8 in 63.0 ft 1.53% 4.28 ft/s 1.49 cfs 75.6% OK OK1-6 0 sf 0 sf 0.00 ac 0.00 6.3 0.63 8.03 0.69 2.36 in/hr 0.00 cfs 1.75 cfs 27.28 26.27 12 in 144.0 ft 0.70% 3.80 ft/s 2.98 cfs 58.6% OK OK1-5A 5,377 sf 597 sf 0.14 ac 0.84 6.3 0.49 8.52 0.66 2.27 in/hr 0.26 cfs 2.23 cfs 26.27 24.90 12 in 135.0 ft 1.02% 4.57 ft/s 3.59 cfs 62.2% OK OK1-4A 7,832 sf 870 sf 0.20 ac 0.84 6.3 0.19 8.71 0.65 2.23 in/hr 0.37 cfs 2.84 cfs 24.65 24.38 15 in 46.0 ft 0.60% 4.08 ft/s 5.00 cfs 56.9% OK OK1-3 0 sf 0 sf 0.00 ac 0.00 6.3 0.02 8.73 0.65 2.23 in/hr 0.00 cfs 2.84 cfs 24.38 24.33 15 in 5.0 ft 0.90% 4.99 ft/s 6.13 cfs 46.4% OK OKSD LINE #1 WQ 0 sf 0 sf 0.00 ac 0.00 6.3 0.11 8.84 0.65 2.21 in/hr 0.00 cfs 2.84 cfs 21.28 21.11 15 in 28.0 ft 0.60% 4.08 ft/s 5.00 cfs 56.9% OK OK1-2 0 sf 0 sf 0.00 ac 0.00 6.3 0.67 9.52 0.62 2.11 in/hr 0.00 cfs 2.84 cfs 21.11 20.12 15 in 165.0 ft 0.60% 4.08 ft/s 5.00 cfs 56.9% OK OK1-1 0 sf 0 sf 0.00 ac 0.00 6.3 0.17 9.69 0.61 2.08 in/hr 0.00 cfs 11.87 cfs 19.37 19.17 24 in 49.0 ft 0.42% 4.67 ft/s 14.66 cfs 81.0% OK OKQuendall TerminalsDrainage ReportFigure 3B: Conveyance Calculations
KPFF Consulting EngineersNovember, 2009STORM DRAIN LINE #2Drainage Calculations - Conveyance Check for the 25-year Storm EventASSUMPTIONS AND CONSTANTSManning's n = 0.013 (per KCSWDM Table 4.2.1 D for PVC pipe - Uniform flow analysis)Pr = 3.43 in. (for 25-yr 24-hr event per KCSWDM Figure 3.2.1.C)ar = 2.66 (for 25-year event per KCSWDM Table 3.2.1.B)br = 0.65 (for 25-year event per KCSWDM Table 3.2.1.B) Tc = 6.3 minutes (minimum Tc)C impervious = 0.90 (per KCSWDM Table 3.2.1.A for Pavement and Roofs)C pervious = 0.25 (per KCSWDM Table 3.2.1.A for Lawns)V min. allow. = 3.0 ft/s (for Pipes, per KCSWDM Figure 4.2.1.F)V max. allow. = 5.0Layout Contributing Flow Calculations (Rational Method)Pipe Capacity Calculations Conveyance ChecksStructure NumberImpervious AreaPervious AreaArea C Tc TfTcENDi25-yrI25-yrContributing QQTotalInlet Invert ElevationOutlet Invert ElevationPipe DiameterLength SlopeVelocity, VPipe Flow Capacity, QPipe Capacity UsedVFull CheckQ Check(sf) (sf) (acres) (min) (min) (min) (in/hr/in) (in/hr) (cfs) (cfs) (inches) (feet) (%) (ft/s) (cfs) (%)Storm Drainage Area: STORM DRAIN LINE #20NE QUAD 26,900 sf 0 sf 0.62 ac 0.90 6.3 0.25 6.55 0.78 2.69 in/hr 1.49 cfs 1.49 cfs 27.90 27.02 12 in 75.0 ft 1.18% 4.93 ft/s 3.87 cfs 38.6% OK OKSE QUAD 128,365 sf 0 sf 2.95 ac 0.90 6.3 0.10 6.40 0.80 2.73 in/hr 7.24 cfs 7.24 cfs 27.40 26.52 18 in 49.0 ft 1.79% 7.95 ft/s 14.05 cfs 51.5% OK OKBYPASS-2 0 sf 0 sf 0.00 ac 0.00 6.3 0.49 7.05 0.75 2.56 in/hr 0.00 cfs 8.73 cfs 26.52 21.97 18 in 241.0 ft 1.89% 8.17 ft/s 14.44 cfs 60.5% OK OKBYPASS-1 0 sf 0 sf 0.00 ac 0.00 6.3 0.20 7.25 0.73 2.52 in/hr 0.00 cfs 8.73 cfs 21.97 20.23 18 in 97.0 ft 1.79% 7.95 ft/s 14.05 cfs 62.1% OK OK2-6 5,769 sf 641 sf 0.15 ac 0.84 6.3 0.28 6.58 0.78 2.68 in/hr 0.33 cfs 0.33 cfs 25.69 24.31 8 in 77.0 ft 1.79% 4.63 ft/s 1.62 cfs 20.4% OK OK2-5 5,743 sf 638 sf 0.15 ac 0.84 6.3 0.17 6.47 0.79 2.71 in/hr 0.33 cfs 0.33 cfs 25.69 24.31 8 in 56.0 ft 2.47% 5.44 ft/s 1.90 cfs 17.5% OK OK2-7B 9,110 sf 1,012 sf 0.23 ac 0.84 6.3 0.06 6.36 0.80 2.74 in/hr 0.53 cfs 0.53 cfs 25.60 24.82 8 in 22.0 ft 3.53% 6.50 ft/s 2.27 cfs 23.4% OK OK2-9B 4,760 sf 529 sf 0.12 ac 0.84 8.3 0.03 8.33 0.67 2.30 in/hr 0.23 cfs 0.23 cfs 28.60 25.98 8 in 20.0 ft 13.10% 12.53 ft/s 4.37 cfs 5.3% OK OK2-10B 6,531 sf 726 sf 0.17 ac 0.84 6.3 0.10 6.40 0.80 2.73 in/hr 0.38 cfs 0.38 cfs 28.60 28.40 8 in 20.0 ft 1.00% 3.46 ft/s 1.21 cfs 31.4% OK OK2-10A 6,531 sf 726 sf 0.17 ac 0.84 6.3 1.17 7.56 0.71 2.45 in/hr 0.34 cfs 0.72 cfs 28.40 25.98 8 in 242.0 ft 1.00% 3.46 ft/s 1.21 cfs 59.6% OK OK2-9A 4,838 sf 538 sf 0.12 ac 0.84 6.3 0.22 8.55 0.66 2.26 in/hr 0.23 cfs 1.19 cfs 25.65 25.30 12 in 50.0 ft 0.70% 3.80 ft/s 2.98 cfs 39.8% OK OK2-11B 5,070 sf 563 sf 0.13 ac 0.84 6.3 0.05 6.35 0.80 2.74 in/hr 0.30 cfs 0.30 cfs 28.60 27.95 8 in 20.0 ft 3.27% 6.26 ft/s 2.18 cfs 13.6% OK OK2-11A 5,149 sf 572 sf 0.13 ac 0.84 6.3 0.19 6.54 0.78 2.69 in/hr 0.30 cfs 0.59 cfs 27.95 25.63 8 in 71.0 ft 3.27% 6.26 ft/s 2.18 cfs 27.1% OK OK2-12B 7,501 sf 833 sf 0.19 ac 0.84 6.3 0.04 6.34 0.80 2.75 in/hr 0.44 cfs 0.44 cfs 28.30 26.93 8 in 22.0 ft 6.21% 8.63 ft/s 3.01 cfs 14.6% OK OK2-13B 2,328 sf 259 sf 0.06 ac 0.84 6.3 0.05 6.35 0.80 2.75 in/hr 0.14 cfs 0.14 cfs 29.30 28.13 8 in 22.0 ft 5.30% 7.97 ft/s 2.78 cfs 4.9% OK OK2-17B 4,050 sf 450 sf 0.10 ac 0.84 6.3 0.18 6.48 0.79 2.71 in/hr 0.23 cfs 0.23 cfs 29.60 29.22 8 in 38.0 ft 1.01% 3.48 ft/s 1.21 cfs 19.2% OK OK2-17A 4,799 sf 533 sf 0.12 ac 0.84 6.3 0.29 6.77 0.77 2.63 in/hr 0.27 cfs 0.50 cfs 29.22 28.60 8 in 61.0 ft 1.01% 3.48 ft/s 1.21 cfs 41.4% OK OK2-15B 5,478 sf 609 sf 0.14 ac 0.84 6.3 0.20 6.50 0.79 2.70 in/hr 0.32 cfs 0.32 cfs 29.60 29.30 8 in 38.0 ft 0.80% 3.10 ft/s 1.08 cfs 29.2% OK OK2-16B 3,645 sf 405 sf 0.09 ac 0.84 6.3 0.17 6.47 0.79 2.71 in/hr 0.21 cfs 0.21 cfs 31.30 30.88 8 in 38.0 ft 1.10% 3.63 ft/s 1.27 cfs 16.6% OK OK2-16A 4,759 sf 529 sf 0.12 ac 0.84 6.3 0.66 7.14 0.74 2.54 in/hr 0.26 cfs 0.47 cfs 30.88 29.30 8 in 144.0 ft 1.10% 3.63 ft/s 1.27 cfs 36.9% OK OK2-15A 6,804 sf 756 sf 0.17 ac 0.84 6.3 0.14 7.28 0.73 2.51 in/hr 0.36 cfs 1.15 cfs 29.30 28.60 8 in 39.0 ft 1.80% 4.64 ft/s 1.62 cfs 70.8% OK OK2-14 0 sf 0 sf 0.00 ac 0.00 6.3 0.29 7.57 0.71 2.45 in/hr 0.00 cfs 1.65 cfs 28.26 27.80 12 in 66.0 ft 0.70% 3.80 ft/s 2.98 cfs 55.3% OK OK2-13A 2,327 sf 259 sf 0.06 ac 0.84 6.3 0.62 8.18 0.68 2.33 in/hr 0.12 cfs 1.90 cfs 27.80 26.60 12 in 150.0 ft 0.80% 4.06 ft/s 3.19 cfs 59.7% OK OK2-12A 7,501 sf 833 sf 0.19 ac 0.84 6.3 0.41 8.59 0.66 2.25 in/hr 0.36 cfs 2.70 cfs 26.60 25.30 12 in 118.0 ft 1.10% 4.76 ft/s 3.74 cfs 72.3% OK OK2-8 0 sf 0 sf 0.00 ac 0.00 6.3 0.90 9.49 0.62 2.11 in/hr 0.00 cfs 4.48 cfs 24.80 23.99 18 in 202.0 ft 0.40% 3.76 ft/s 6.64 cfs 67.4% OK OK2-7A 9,110 sf 1,012 sf 0.23 ac 0.84 6.3 0.41 9.90 0.60 2.06 in/hr 0.40 cfs 5.41 cfs 23.99 23.48 18 in 103.0 ft 0.50% 4.20 ft/s 7.43 cfs 72.8% OK OK2-4 0 sf 0 sf 0.00 ac 0.00 6.3 0.07 9.96 0.60 2.05 in/hr 0.00 cfs 6.07 cfs 23.48 23.37 18 in 18.0 ft 0.60% 4.60 ft/s 8.14 cfs 74.6% OK OKSD LINE #2 WQ 0 sf 0 sf 0.00 ac 0.00 6.3 0.06 10.02 0.59 2.04 in/hr 0.00 cfs 6.07 cfs 20.32 20.23 18 in 16.0 ft 0.60% 4.60 ft/s 8.14 cfs 74.6% OK OK2-2 0 sf 0 sf 0.00 ac 0.00 6.3 0.22 10.24 0.59 2.01 in/hr 0.00 cfs 14.80 cfs 19.23 19.04 30 in 61.0 ft 0.30% 4.58 ft/s 22.47 cfs 65.9% OK OK2-1 0 sf 0 sf 0.00 ac 0.00 6.3 0.08 10.32 0.58 2.00 in/hr 0.00 cfs 14.80 cfs 19.04 18.98 30 in 21.0 ft 0.30% 4.58 ft/s 22.47 cfs 65.9% OK OKQuendall TerminalsDrainage ReportFigure 3B: Conveyance Calculations
KPFF Consulting EngineersNovember, 2009STORM DRAIN LINE #3Drainage Calculations - Conveyance Check for the 25-year Storm EventASSUMPTIONS AND CONSTANTSManning's n = 0.013 (per KCSWDM Table 4.2.1 D for PVC pipe - Uniform flow analysis)Pr = 3.43 in. (for 25-yr 24-hr event per KCSWDM Figure 3.2.1.C)ar = 2.66 (for 25-year event per KCSWDM Table 3.2.1.B)br = 0.65 (for 25-year event per KCSWDM Table 3.2.1.B) Tc = 6.3 minutes (minimum Tc)C impervious = 0.90 (per KCSWDM Table 3.2.1.A for Pavement and Roofs)C pervious = 0.25 (per KCSWDM Table 3.2.1.A for Lawns)V min. allow. = 3.0 ft/s (for Pipes, per KCSWDM Figure 4.2.1.F)V max. allow. = 5.0Layout Contributing Flow Calculations (Rational Method)Pipe Capacity Calculations Conveyance ChecksStructure NumberImpervious AreaPervious AreaArea C Tc TfTcENDi25-yrI25-yrContributing QQTotalInlet Invert ElevationOutlet Invert ElevationPipe DiameterLength SlopeVelocity, VPipe Flow Capacity, QPipe Capacity UsedVFull CheckQ Check(sf) (sf) (acres) (min) (min) (min) (in/hr/in) (in/hr) (cfs) (cfs) (inches) (feet) (%) (ft/s) (cfs) (%)Storm Drainage Area: STORM DRAIN LINE #30NW QUAD 84,180 sf 0 sf 1.93 ac 0.90 6.3 0.06 6.36 0.80 2.74 in/hr 4.77 cfs 4.77 cfs 20.20 20.10 18 in 16.0 ft 0.60% 4.60 ft/s 8.14 cfs 58.6% OK OK3-4B 4,228 sf 470 sf 0.11 ac 0.84 4.3 0.03 4.33 1.03 3.52 in/hr 0.32 cfs 0.32 cfs 26.70 24.56 8 in 20.0 ft 10.70% 11.32 ft/s 3.95 cfs 8.0% OK OK3-6B 4,733 sf 526 sf 0.12 ac 0.84 6.3 0.05 6.35 0.80 2.75 in/hr 0.28 cfs 0.28 cfs 28.50 27.60 8 in 20.0 ft 4.50% 7.34 ft/s 2.56 cfs 10.8% OK OK3-6A 4,733 sf 526 sf 0.12 ac 0.84 6.3 0.09 6.44 0.79 2.72 in/hr 0.27 cfs 0.55 cfs 27.60 25.76 8 in 40.0 ft 4.60% 7.42 ft/s 2.59 cfs 21.3% OK OK3-7B 3,356 sf 373 sf 0.09 ac 0.84 6.3 0.03 6.33 0.80 2.75 in/hr 0.20 cfs 0.20 cfs 28.30 26.15 8 in 20.0 ft 10.73% 11.34 ft/s 3.96 cfs 5.0% OK OKNE PARKING 63,940 sf 0 sf 1.47 ac 0.90 6.3 0.03 6.33 0.80 2.75 in/hr 3.63 cfs 3.63 cfs 25.50 25.32 12 in 11.0 ft 1.60% 5.74 ft/s 4.51 cfs 80.6% OK OK3-8B 2,263 sf 251 sf 0.06 ac 0.84 8.3 0.03 8.33 0.67 2.30 in/hr 0.11 cfs 0.11 cfs 29.30 27.02 8 in 20.0 ft 11.40% 11.69 ft/s 4.08 cfs 2.7% OK OK3-11B 1,096 sf 122 sf 0.03 ac 0.84 6.3 0.07 6.37 0.80 2.74 in/hr 0.06 cfs 0.06 cfs 30.40 29.16 8 in 30.0 ft 4.12% 7.03 ft/s 2.45 cfs 2.6% OK OK3-11A 0 sf 0 sf 0.00 ac 0.00 6.3 0.07 6.44 0.79 2.72 in/hr 0.00 cfs 0.06 cfs 29.16 27.98 8 in 28.0 ft 4.22% 7.11 ft/s 2.48 cfs 2.6% OK OK3-10B 7,059 sf 784 sf 0.18 ac 0.84 6.3 0.18 6.48 0.79 2.71 in/hr 0.41 cfs 0.41 cfs 29.60 29.22 8 in 38.0 ft 1.00% 3.46 ft/s 1.21 cfs 33.7% OK OK3-10A 7,849 sf 872 sf 0.20 ac 0.84 6.3 0.60 7.08 0.75 2.56 in/hr 0.43 cfs 0.83 cfs 29.22 27.98 8 in 124.0 ft 1.00% 3.46 ft/s 1.21 cfs 69.0% OK OK3-9 0 sf 0 sf 0.00 ac 0.00 6.3 0.60 7.68 0.71 2.43 in/hr 0.00 cfs 0.90 cfs 27.65 26.69 12 in 136.0 ft 0.70% 3.80 ft/s 2.98 cfs 30.1% OK OK3-8A 2,730 sf 303 sf 0.07 ac 0.84 6.3 0.55 8.88 0.64 2.21 in/hr 0.13 cfs 1.14 cfs 26.69 25.82 12 in 125.0 ft 0.70% 3.80 ft/s 2.98 cfs 38.2% OK OK3-7A 3,506 sf 390 sf 0.09 ac 0.84 6.3 0.31 9.19 0.63 2.16 in/hr 0.16 cfs 5.13 cfs 25.32 24.93 18 in 78.0 ft 0.50% 4.20 ft/s 7.43 cfs 69.0% OK OK3-5 0 sf 0 sf 0.00 ac 0.00 6.3 0.72 9.91 0.60 2.05 in/hr 0.00 cfs 5.68 cfs 24.93 23.73 18 in 200.0 ft 0.60% 4.60 ft/s 8.14 cfs 69.8% OK OK3-4A 4,194 sf 466 sf 0.11 ac 0.84 6.3 0.02 9.93 0.60 2.05 in/hr 0.18 cfs 6.18 cfs 23.73 23.69 18 in 6.0 ft 0.70% 4.97 ft/s 8.79 cfs 70.3% OK OKSD LINE #3 WQ 0 sf 0 sf 0.00 ac 0.00 6.3 0.02 9.95 0.60 2.05 in/hr 0.00 cfs 6.18 cfs 20.64 20.60 18 in 5.0 ft 0.70% 4.97 ft/s 8.79 cfs 70.3% OK OK3-1 0 sf 0 sf 0.00 ac 0.00 6.3 0.24 10.19 0.59 2.02 in/hr 0.00 cfs 10.95 cfs 20.10 19.84 24 in 66.0 ft 0.40% 4.55 ft/s 14.31 cfs 76.5% OK OKQuendall TerminalsDrainage ReportFigure 3B: Conveyance Calculations
KPFF Consulting EngineersNovember, 2009BASIN AREASSTORMFILTER CALCULATIONSBasin areas are for Storm Drain Lines #1, #2, and #3, which carry PGIS StormFilter design per Section 6.5.5 of 2009 KCSWDM.from streets and open-air parking to water quality treatment facilities. Treatment flow is 35% of the developed 2-year peak flow rate determined using KCRTS and 15-minute times steps.Sea-Tac 1.0 scale factor used in KCRTS.Cartridge design flows per Table 6.5.5.A of 2009 KCSWDM.STORM DRAIN LINE #1TOT 57810 [SF] = 1.33 [AC]NUMBER OF CARTRIDGESIMP 90% 52029 [SF] = 1.19 [AC]12" (5 GPM) 18" (7.5 GPM) 27" (11.3 GPM)PERV 10% 5781 [SF] = 0.13 [AC] SD LINE #1 0.572 [CFS] * 35% = 0.2002 [CFS] = 89.9 [GPM] 18 12 8SD LINE #2 1.23 [CFS] * 35% = 0.4305 [CFS] = 193.2 [GPM] 39 26 18STORM DRAIN LINE #2 SD LINE #3 1.20 [CFS] * 35% = 0.42 [CFS] = 188.5 [GPM] 38 26 17TOT 124226 [SF] = 2.85 [AC]IMP 90% 111803 [SF] = 2.57 [AC]PERV 10% 12423 [SF] = 0.29 [AC]STORM DRAIN LINE #3 (INCLUDES NE QUAD PARKING)TOT 114770 [SF] = 2.63 [AC]IMP 95.6% 109687 [SF] = 2.52 [AC]PERV 4.4% 5083 [SF] = 0.12 [AC]PRESETTLING TANK VOLUMESPresettling prior to StormFilter per Section 6.5.1 of 2009 KCSWDM.PRESETTLING VOLUME = 0.75*VrVr = (0.9*Ai + 0.25*Atg + 0.10*Atf + 0.01*Ao)*R(Eq 6-13, 2009 KCSWDM)Ai = IMPAtg = PERVAtf = 0Ao = 0R = 0.039 [FT] (Fig 6.4.1.A, 2009 KCSWDM)SD LINE #1 SD LINE #2 SD LINE #3Vr[CF] 1883 4045 39000.75*Vr[CF] 1412 3034 29252-YR FLOW WQ FLOWQuendall TerminalsDrainage ReportFigure 4B: Water Quality Calculations
SD Line #1.pks
Flow Frequency Analysis
Time Series File:sd line #1.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis-------
Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS) Period
0.572 6 8/27/01 18:00 1.48 1 100.00 0.990
0.399 8 9/17/02 17:45 1.11 2 25.00 0.960
1.11 2 12/08/02 17:15 0.780 3 10.00 0.900
0.460 7 8/23/04 14:30 0.647 4 5.00 0.800
0.613 5 10/28/04 16:00 0.613 5 3.00 0.667
0.647 4 10/27/05 10:45 0.572 6 2.00 0.500
0.780 3 10/25/06 22:45 0.460 7 1.30 0.231
1.48 1 1/09/08 6:30 0.399 8 1.10 0.091
Computed Peaks 1.36 50.00 0.980
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KPFF Consulting Engineers
SD Line #1.pksSD Line #1.pks
11/2009
0.572 6 2.00 0.5000.572 6 2.00 0.500
Quendall Terminals Storm Drainage Report Figure 4B: WQ Calcs
SD Line #2.pks
Flow Frequency Analysis
Time Series File:sd line #2.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis-------
Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS) Period
1.23 6 8/27/01 18:00 3.18 1 100.00 0.990
0.854 8 9/17/02 17:45 2.38 2 25.00 0.960
2.38 2 12/08/02 17:15 1.67 3 10.00 0.900
0.986 7 8/23/04 14:30 1.39 4 5.00 0.800
1.31 5 10/28/04 16:00 1.31 5 3.00 0.667
1.39 4 10/27/05 10:45 1.23 6 2.00 0.500
1.67 3 10/25/06 22:45 0.986 7 1.30 0.231
3.18 1 1/09/08 6:30 0.854 8 1.10 0.091
Computed Peaks 2.91 50.00 0.980
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KPFF Consulting Engineers
SD Line #2.pksSD Line #2.pks
11/2009
1.23 6 2.00 0.500 1.23 6 2.00 0.500
Quendall Terminals Storm Drainage Report Figure 4B: WQ Calcs
SD Line #3.pks
Flow Frequency Analysis
Time Series File:sd line #3.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis-------
Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS) Period
1.20 6 8/27/01 18:00 3.03 1 100.00 0.990
0.838 8 9/17/02 17:45 2.30 2 25.00 0.960
2.30 2 12/08/02 17:15 1.63 3 10.00 0.900
0.966 7 8/23/04 14:30 1.35 4 5.00 0.800
1.28 5 10/28/04 16:00 1.28 5 3.00 0.667
1.35 4 10/27/05 10:45 1.20 6 2.00 0.500
1.63 3 10/25/06 22:45 0.966 7 1.30 0.231
3.03 1 1/09/08 6:30 0.838 8 1.10 0.091
Computed Peaks 2.79 50.00 0.980
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KPFF Consulting Engineers
SD Line #3.pksSD Line #3.pks
11/2009
1.20 6 2.00 0.500 1.20 6 2.00 0.500
Quendall Terminals Storm Drainage Report Figure 4B: WQ Calcs