HomeMy WebLinkAboutTIR-3998
Western Washington Division Eastern Washington Division
165 NE Juniper St., Ste 201, Issaquah, WA 98027 108 East 2nd Street, Cle Elum, WA 98922
Phone: (425) 392-0250 Fax: (425) 391-3055 Phone: (509) 674-7433 Fax: (509) 674-7419
www.EncompassES.net
TECHNICAL INFORMATION REPORT
For
Matveyev Short Plat
1810 Park Avenue North
Renton, WA 98056
January 10, 2018
Revised: May 16, 2019
Prepared by:
Samuel Salo
Encompass Engineering Job No. 16645
Prepared For:
Emil Matveyev
807 Kirkland Way
Kirkland, WA 98033
5/15/15/15/16666/19/19/19/19
SURFACE WATER UTILITY
jfarah 07/10/2019
DEVELOPMENT ENGINEERING
swarlick 07/24/2019
Matveyev Short Plat Technical Information Report
5/16/19 P a g e i
Table of Contents
I. PROJECT OVERVIEW ................................................................................................................ 1
II. CONDITIONS AND REQUIREMENTS SUMMARY ...................................................................... 3
III. OFF-SITE ANALYSIS .................................................................................................................. 5
IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ........................... 12
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ..................................................................... 14
VI. SPECIAL REPORTS AND STUDIES ............................................................................................ 15
VII. OTHER PERMITS ..................................................................................................................... 15
VIII. CSWPPP ANALYSIS AND DESIGN............................................................................................ 15
IX. BOND QUANTITIES and DECLARATION of COVENANT .......................................................... 17
X. OPERATION AND MAINTENANCE MANUAL .......................................................................... 17
Appendix A
Geotechnical Engineering Study by Earth Solutions NW LLC dated May 18, 2017
Appendix B
Bond Quantity Worksheet
Appendix C
Operations and Maintenance
Appendix D
Complete WWHM2012 Output
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I. PROJECT OVERVIEW
Site Address: 3810 Park Avenue North, Renton WA, 98056 (see Vicinity Map)
King County Tax Parcel: 334270-0510
Vicinity Map
This project proposes to subdivide this 0.48-acre parcel into two single-family residential lots and
a shared driveway tract. This site is within the Residential-6 (R-6) Zone. One single-family
residence is presently on the property and will be removed prior to construction. One new lot
(Lot 2), east of the existing residence, is proposed for a new single-family home. The proposed
lot sizes are 7,947 SF for Lot 1 and 10,047 SF for Lot 2. There is also a 2,401 SF Tract proposed to
provide access to the proposed lots. The site generally slopes to the north and northwest at 8
percent. Moderate landslide hazards and sensitive slopes are mapped within 50 feet of the
project site. The soil of the site is mapped as silty sand and sandy silt per the Geotechnical
Engineering Study by Earth Solutions NW, LLC (see appendix A) and Indianola loamy sand per the
web soils survey (see map on next page).
Pre-developed Site Conditions:
The project site presently consists of a single-family residence with a detached garage and a
paved driveway that provides access to Park Avenue N. Except for the structures and driveway,
the site is vegetated with grass areas and shrubs.
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Post-developed Site Conditions:
This proposal incorporates the construction of on-site and off-site infrastructure to support the
future construction of 2 new single-family detached residences. All existing structures will be
demolished prior to the start of construction. The lots will be accessed via one driveway within
Tract A that connects to Park Avenue N. Developed rooftop runoff will be routed to on-site
dispersion trenches. Storm water quality is not required since the new pollution generating
impervious surface is less than 5,000 SF. The pervious landscape areas will be allowed to infiltrate
naturally into the native soil.
The project abuts Park Avenue N to the East. The proposed off-site frontage improvements along
Park Avenue N include the installation of 6’ parking lane, curb, gutter, 8’ landscape strip and a 5’
sidewalk within the 16’ ROW dedication and additional 6.5’ ROW dedication.
Soils Map
Proposed Drainage Controls
A 15’ dispersion trench will be installed on lot two with a 25’ vegetated flowpath segment. This
allows up to 1,050 SF of impervious area to be mitigated on Lot 2. Due to the site topography we
are not able to provide flow control BMPs for Lot 1, Tract A or the frontage improvements.
Dispersion is not feasible as these areas downstream of our project site. Infiltration BMPs are
infeasible due to poorly infiltrating soils per the Geotechnical Engineering Study. This project also
proposes to use reduced impervious surface credits per Section C.2.9 of the 2017 City of Renton
Surface Water Design Manual to meet minimum stormwater mitigation requirements. (See
Section IV for additional information on BMPs and Appendix A for more soils information).
SITE
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II. CONDITIONS AND REQUIREMENTS SUMMARY
CORE REQUIREMENTS
Core Requirement #1: Discharge at the Natural Location
Runoff from the eastern portion of the site generally sheet flows to the northern edge of
the property. Runoff from the western portion of the site sheet flows to the northwest
edge of the site. This drainage pattern will be maintained as the site is developed.
Core Requirement #2: Offsite Analysis
An offsite drainage analysis is provided in Section III of this TIR. Level 1 Drainage Analysis
has been performed and no problems downstream have been identified.
Core Requirement #3: Flow Control Facilities
This project lies within the Peak Rate flow control applications area, therefore
predeveloped conditions may be modeled as existing. Flow control facilities are not
required since the project does not generate 0.15-cfs increase in the existing site
conditions 100-year peak flow using 15-minute timesteps per the 2017 City of Renton
Surface Water Design Manual. Basic flow control BMPs will be utilized for the proposed
lots.
Core Requirement #4: Conveyance System
Conveyance system analysis is not warranted for this project.
Core Requirement #5: Erosion & Sediment Control
A temporary erosion and sediment control (TESC) plan is included with this submittal. See
Section VIII of this TIR for a list of BMPs to be utilized.
Core Requirement #6: Maintenance & Operations
An Operation and Maintenance Manual is provided in Appendix C.
Core Requirement #7: Financial Guarantees & Liability
The owner will arrange for any financial guarantees and liabilities required by the permit.
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Core Requirement #8: Water Quality Facilities
A tract of 1,600 sf and a driveway area of 1,543 SF for the lots have been proposed. This
gives us 3,143 SF of PGIS. This is less than 5,000 SF threshold, therefore the project is
exempt from the water quality requirement.
Core Requirement #9: On-Site BMP’s
A 15’ dispersion trench will be installed on lot two with a 25’ vegetated flowpath segment.
This allows up to 1,050 SF of impervious area to be mitigated on Lot 2. Due to the site
topography we are not able to provide flow control BMPs for Lot 1, Tract A or the frontage
improvements. Dispersion is not feasible as these areas downstream of our project site.
Infiltration BMPs are infeasible due to poorly infiltrating soils per the Geotechnical
Engineering Study. This project also proposes to use reduced impervious surface credits
per Section C.2.9 of the 2017 City of Renton Surface Water Design Manual to meet
minimum stormwater mitigation requirements. (See Section IV for additional information
on BMPs and Appendix A for more soils information).
SPECIAL REQUIREMENTS:
Special Requirement #1: Other Adopted Area-Specific Requirements
This site does not fall under any other adopted area-specific requirements per the city of
Renton surface water design manual. Page 1 – 89, Section 1.3.1
Critical Drainage Area – N/A
Master Drainage Plan – N/A
Basin Plan – N/A
Lake Management Plan –N/A
Shared Facility Drainage Plan – N/A
Special Requirement #2: Flood Hazard Area Delineation
This site does not fall under the flood hazard area delineation requirements per the
Renton Surface Water Design Manual. Page - 1-90, Section 1.3.2
Special Requirement #3: Flood Protection Facilities
This site does not fall under the flood protection facilities requirements per the Renton
Surface Water Design Manual. Page – 1-91, Section 1.3.3
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Special Requirement #4: Source control
This site does not fall under the source control requirements per the Renton Surface
Water Design Manual. Page – 1-92, Section 1.3.4
Special Requirement #5: Oil Control
This site does not fall under the oil control requirements per the Renton Surface Water
Design Manual. Page – 1-94, Section 1.3.5
Special Requirement #6: Aquifer Protection Areas
This site does not fall under the aquifer protection areas requirement per the Renton
Surface Water Design Manual. Page – 1-97, Section 1.3.6
III. OFF-SITE ANALYSIS
The level 1 analysis was done Thursday June 1, 2017 around 9:00AM. The weather was cloudy
with some rain, roughly 59°. The site is currently developed with a single-family residence,
detached garage and driveway access. The site is comprised of tall grasses with trees and shrubs
throughout. There are two flow patterns for the site. The eastern portion of the sight slopes to
the north. The western portion slopes to the west and northwest.
Runoff from the eastern portion of the site generally sheet flows to the northern edge of the
property. It then flows through the adjacent properties and onto N 39th Pl. where it is collected
by private detention tanks by inlets in the street. The tanks drain through 12” concrete pipe into
the Park Ave N drainage system. This is where it converges with the runoff from the western
portion of the site.
Runoff from the western portion of the site generally sheet flows towards the northeast corner
of the property with some concentrated flow on the driveway. Runoff is then collected in 24”
drainage ditch to a 12” concrete culvert passing under the driveway. After traveling 26’ through
another drainage ditch of similar size runoff is then fed into a 12” concrete pipe entering the Park
Avenue drainage system. This is where it converges with the runoff from the eastern portion of
the site. It then flows north to N 40th Street N through a series of 12” concrete and ductile iron
pipe. Runoff then travels west along N 40th Street N and under Lake Washington Blvd through
18” corrugated plastic pipe, then under the Burlington Northern Inc. Railroad through 24”
corrugated plastic pipe. Here the runoff travels through a 2’ wide 27’ long drainage channel
before entering a 24” corrugated plastic pipe leading under Wells Ave N. This is where the level
1 analysis was completed. Using the city of Renton CORMaps we see that the runoff then travels
through another series of pipes before being discharged into Lake Washington. (See Downstream
Map)
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Downstream Map
Photo 1 – Existing Conditions and Development
SITE
Conversion Point
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Photo 2 – Drainage Ditch South of Driveway on Park Avenue
Photo 3 – Drainage Ditch North of Driveway on Park Avenue
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Photo 4 – Transition to 12” Ductile Iron Pipe
Photo 5 – Drainage Channel from Burlington Northern Railroad
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Map of Photo Locations
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IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
Flow Control BMPs
Based on the geotechnical report and addendum, infiltration is not feasible for the site due to
the soil types. It is required that 10% of the lot area be mitigated for flow control. Lot 1 is 7,947
SF therefore we need flow control for 10% or 795 SF. Lot 2 is 10,047 SF therefore we need flow
control for 10% or 1,005 SF. It was decided that 10’ trench with a 25’ flow vegetated flow path
segment would be installed on Lot 2. This will mitigate 700 SF of impervious surface from the lot.
The remaining area to be mitigated is 305 SF. Due to site area we cannot lengthen the trench to
disperse more area. The soils on-site cannot infiltrate therefore permeable pavement, limited or
full infiltration and bioretention are not feasible. This project also proposes to use reduced
impervious surface credits per Section C.2.9 of the 2017 City of Renton Surface Water Design
Manual. The maximum allowable impervious surface for Lot 1 is 3,205 SF (4,000 SF – 795 SF). The
maximum allowable impervious surface for Lot 2 is 3,695 (4,000 SF – 305 SF). No other BMPs are
feasible for the project site, therefore this design mitigates stormwater runoff to the maximum
extent feasible.
Flow Control
The site is exempt from providing flow control as the difference in 100-Year Peaks is 0.2568-
0.2348 = 0.022 which is less than 0.15 CFS. This site also falls under the Peak Rate flow control
applications area, therefore predeveloped conditions can be modeled as existing (see area
calculations and WWHM analysis on next page).
Area Calculations:
Area Breakdown:
Site Area – 20,395 SF or 0.47 Acre
Impervious Area Calculation for WWHM:
· The proposed improvements include dividing the parcel into two separate lots. Lot 1 will
be 7,947 sf and Lot 2 will be 10,047 SF. There will also be a tract of land (Tract A) that is
2,401 SF and an offsite area of 1,625 SF. The existing impervious area is 4,115 SF. The
proposed impervious area is 7,906 SF. The offsite area was not included in the model due
to the increase in 100- year flows of 0.022 CFS. Adding in the offsite area will not push
this over the 0.15 CFS threshold.
Tract A: 1,600 SF
Lot 1: Maximum Impervious = 3,205 SF
Lot 2: Maximum Impervious = 3,695 SF
TOTAL IMPERVIOUS: 8,500 SF (0.19 AC)
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WWHM Analysis
Soil Type: Existing and Developed– Indianola Loamy Sand
Existing Conditions:
Developed Conditions:
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V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
A conveyance system analysis was performed using King County iMap and WWHM2012. iMap
was used to first estimate the area tributary to our proposed storm drainage system. This was
found to be approximately 8.19 Acres. This area appeared to be approximately 45% impervious.
This area was then modeled in WWHM resulting in a 25-year return flow rate of 3.16 CFS. A 12”
CPP at 0.5% is capable of conveying 3.2 CFS, therefore our system is capable of conveying the
upstream tributary area. See map and detailed description of calculation on following page.
Map of Upstream Tributary Area
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Map of Pipes
The conveyance calculations were performed using Manning’s Equation. The conveyance system
was checked to ensure that during the 25-year storm event, the system would function
adequately. The 100-year peak flow from the developed site using WWHM2012 with 15 minute
time steps was compared to the maximum capacity of the pipe. Using the Manning’s Equation,
the maximum capacity of a 6”, 8” and 12” pipe for reference was calculated:
Pipe Diameter
(inches)
Pipe Slope Capacity (CFS)
6 1.0% 0.65
8 0.50% 1.34
12 0.50% 3.20
As shown in the table the capacity of the 12” pipe is greater than the 3.16 CFS required to convey
the upstream tributary area.
VI. SPECIAL REPORTS AND STUDIES
Geotechnical Engineering Study by Earth Solutions NW LLC Dated May 18, 2017
Arborist Report by American Forest Management Dated March 9th 2017
VII. OTHER PERMITS
Building permits will be required.
VIII. CSWPPP ANALYSIS AND DESIGN
The potential for erosion within the site will be mitigated by use of erosion control measures
during clearing, grading, and site development activities. Filter fences will be installed along the
downhill perimeter of the site to protect adjacent properties from sediment-laden water. The
existing access will be installed at the entrance to the site to protect mud from entering the paved
roadway. Stockpiles and exposed disturbed areas will be covered to protect from erosion and
sediment runoff.
Element 1: Mark Clearing Limits. All clearing and grading will be clearly marked in the field prior
to construction in accordance to the plans and specifications. Prior to beginning land disturbing
activities, including clearing and grading, clearly mark all clearing limits, sensitive areas and their
buffers, and trees that are to be preserved within the construction area. These will be clearly
marked, both in the field and on the plans, to prevent damage and offsite impacts. Plastic, metal,
or stake wire fence may be used to mark the clearing limits.
Element 2: Establish Construction Access. The existing access from Park Avenue N will be utilized
as the construction access. Access points will be stabilized with a pad of quarry spalls, crushed
rock, or equivalent BMP prior to traffic leaving the construction site to minimize the tracking of
sediment onto all roads and accesses.
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Element 3: Control Flow Rates. No flow rate control is proposed at this time.
Element 4: Install Sediment Controls. Soils should be covered if not worked for 7 days during the
dry season or 2 days during the wet season. The street should be swept each night or as required.
If the minimum BMPs fail to retain sediment to the sight, additional BMPs will be used.
Element 5: Stabilize Soils. Soils will be covered if not worked for 7 days during the dry season or
2 days during the wet season. Soil stockpiles will be covered unless worked. Soil stockpiles will
be located away from drain inlets and surface water discharge locations. Soil stockpiles will be
stabilized and covered as needed. Soils will be stabilized at the end of the shift before holidays
or weekends if needed based on weather forecast.
Element 6: Protect Slopes. Slope protection is not proposed as there are no slopes on the site.
Element 7: Protect Drain Inlets. Existing drain inlets will be protected during construction
Element 8: Stabilize Channels and Outlets. Existing and proposed drainage outlets will be
stabilized throughout construction.
Element 9: Control Pollutants. Pollution generated from construction must be controlled at all
times. Control of pollutants other than sediments includes the following:
All pollutants other than sediments will be handled and disposed of in a manner that does
not cause contamination of stormwater.
Cover, containment and protection from vandalism will be provided for all chemicals,
liquid products, petroleum products, and non-inert wastes present on the project site.
Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic
system drain down, solvent and de-greasing cleaning operations, fuel tank drain down
and removal, and other activities which may result in discharge or spillage of pollutants
to the ground or into stormwater runoff must be conducted using spill prevention
measures, such as drip pans. Contaminated surfaces will be cleaned immediately
following any discharge or spill incident. Emergency repairs may be performed on-site
using temporary plastic placed beneath and, if raining, over the vehicle.
Element 10: Control De-Watering. De-watering is not anticipated for the site. In the event that
dewatering is necessary, the waste water will be treated such that sediment remains on site. This
will be done by routing the storm water through a straw filter or sediment trap.
Element 11: Maintain BMPs. BMPs will be inspected monthly and after every significant storm
event, Sediment will be removed from the BMPs as necessary for them to continue operating at
the required performance level. In the event that a BMPs has been damaged, it will be replaced
immediately.
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Element 12: Manage the Project. Construction activities will be phased such that the impact to
the area will be kept at a minimum. Coordination will occur with all utility agencies that are
affected by this project. BMPs will be inspected regularly and after each significant storm event.
The Contractor will provide a Certified Erosion and Sediment Control Specialist. If for any reason
a BMPs is not sufficient for the project, additional BMPs will be installed.
IX. BOND QUANTITIES and DECLARATION of COVENANT
Bond Quantities
The bond quantity is included in Appendix B of this TIR.
Facility Summaries
Not applicable.
Declaration of Covenant
The Declaration of Covenant will have to be approved and recorded.
X. OPERATION AND MAINTENANCE MANUAL
Operation and maintenance of the site and all proposed stormwater facilities on this project will
be required after the construction completion and throughout the life of this development.
This development is served by a series of storm drain pipes that collect and convey post
development runoff associated with this project, catch basins, infiltration drywells, and
infiltration trenches. Each storm drainage component mentioned above consists of several items
that need to be properly maintained.
The list below specifies the maintenance requirements for each component of the stormwater
facility being constructed. Applicable maintenance requirements, taken from City of Renton
Stormwater Design Manual, are included in Appendix C. Proposed maintenance requirements
include:
1. Dispersion Trench
2. Catch Basins and Manholes
3. Conveyance Pipes and Ditches
Matveyev Short Plat Technical Information Report
Appendix A
Geotechnical Report
EarthSolutionsNWLLC
EarthSolutionsNWLLC
Geotechnical Engineering
Geology
Environmental Scientists
Construction Monitoring
1805 -136th Place N.E.,Suite 201 Bellevue,WA 98005
(425)449-4704 Fax (425)449-4711
www.earthsolutionsnw.com
GEOTECHNICAL ENGINEERING STUDY
PROPOSED SHORT PLAT
3810 PARK AVENUE NORTH
RENTON,WASHINGTON
ES-5134
Drwn.
Checked Date
Date Proj.No.
Plate
Earth Solutions NWLLC
Geotechnical Engineering,Construction Monitoring
EarthSolutionsNWLLC
EarthSolutionsNWLLC and Environmental Sciences
Vicinity Map
Matveyev Short Plat
Renton,Washington
MRS
CGH
04/28/2017
April 2017
5134
1
NORTH
NOTE:This plate may contain areas of color.ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black &white reproductions of this plate.
Reference:
King County,Washington
Map 626
By The Thomas Guide
Rand McNally
32nd Edition
SITE
Drwn.
Checked Date
Date Proj.No.
Plate
Earth Solutions NWLLC
Geotechnical Engineering,Construction Monitoring
EarthSolutionsNWLLC
EarthSolutionsNWLLC and Environmental Sciences
NORTH
0 20 40 80
Scale in Feet1"=40'
NOTE:This plate may contain areas of color.ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black &white reproductions of this plate.
NOTE:The graphics shown on this plate are not intended for design
purposes or precise scale measurements,but only to illustrate the
approximate test locations relative to the approximate locations of
existing and /or proposed site features.The information illustrated
is largely based on data provided by the client at the time of our
study.ESNW cannot be responsible for subsequent design changes
or interpretation of the data by others.
LEGEND
Approximate Location of
ESNW Test Pit,Proj.No.
ES-5134,Mar.2017
Subject Site
Existing Building
Test Pit Location Plan
Matveyev Short Plat
Renton,Washington
MRS
CGH
05/01/2017
May 2017
5134
2
TP-1 TP-2
TP-4
TP-3
House
Garage
Shed
Landscaping
Pond
TP-1
Asphalt Driveway
PARK AVENUE N.130 140
130
140
Drwn.
Checked Date
Date Proj.No.
Plate
Earth Solutions NWLLC
Geotechnical Engineering,Construction MonitoringandEnvironmentalSciences
EarthSolutionsNWLLC
EarthSolutionsNWLLC
RETAINING WALL DRAINAGE DETAIL
Matveyev Short Plat
Renton,Washington
MRS
CGH
05/01/2017
May 2017
5134
3
NOTES:
Free Draining Backfill should consist
of soil having less than 5 percent fines.
Percent passing #4 should be 25 to
75 percent.
Sheet Drain may be feasible in lieu
of Free Draining Backfill,per ESNW
recommendations.
Drain Pipe should consist of perforated,
rigid PVC Pipe surrounded with 1"
Drain Rock.
LEGEND:
Free Draining Structural Backfill
1 inch Drain Rock
18"Min.
Structural
Fill
Perforated Drain Pipe
(Surround In Drain Rock)
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Drwn.
Checked Date
Date Proj.No.
Plate
Earth Solutions NWLLC
Geotechnical Engineering,Construction Monitoring
and Environmental Sciences
EarthSolutionsNWLLC
EarthSolutionsNWLLC
FOOTING DRAIN DETAIL
Slope
Perforated Rigid Drain Pipe
(Surround with 1"Rock)
18"(Min.)
NOTES:
Do NOT tie roof downspouts
to Footing Drain.
Surface Seal to consist of
12"of less permeable,suitable
soil.Slope away from building.
LEGEND:
Surface Seal;native soil or
other low permeability material.
1"Drain Rock
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Matveyev Short Plat
Renton,Washington
MRS
CGH
05/01/2017
May 2017
5134
4
Matveyev Short Plat Technical Information Report
Appendix B
Bond Quantity Worksheet
CED Permit #:17-000389ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostDRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/DD-126.00$ SY* (CBs include frame and lid)BeehiveD-290.00$ EachThrough-curb Inlet FrameworkD-3400.00$ EachCB Type ID-41,500.00$ Each34,500.0023,000.00CB Type ILD-51,750.00$ EachCB Type II, 48" diameterD-62,300.00$ Each for additional depth over 4' D-7480.00$ FTCB Type II, 54" diameterD-82,500.00$ Each for additional depth over 4'D-9495.00$ FTCB Type II, 60" diameterD-102,800.00$ Each for additional depth over 4'D-11600.00$ FTCB Type II, 72" diameterD-126,000.00$ Each for additional depth over 4'D-13850.00$ FTCB Type II, 96" diameterD-1414,000.00$ Each for additional depth over 4'D-15925.00$ FTTrash Rack, 12"D-16350.00$ EachTrash Rack, 15"D-17410.00$ EachTrash Rack, 18"D-18480.00$ EachTrash Rack, 21"D-19550.00$ EachCleanout, PVC, 4"D-20150.00$ EachCleanout, PVC, 6"D-21170.00$ Each2340.00Cleanout, PVC, 8"D-22200.00$ EachCulvert, PVC, 4" D-2310.00$ LFCulvert, PVC, 6" D-2413.00$ LF1011,313.00Culvert, PVC, 8" D-2515.00$ LF18270.00Culvert, PVC, 12" D-2623.00$ LF1453,335.00Culvert, PVC, 15" D-2735.00$ LFCulvert, PVC, 18" D-2841.00$ LFCulvert, PVC, 24"D-2956.00$ LFCulvert, PVC, 30" D-3078.00$ LFCulvert, PVC, 36" D-31130.00$ LFCulvert, CMP, 8"D-3219.00$ LFCulvert, CMP, 12"D-3329.00$ LFSUBTOTAL THIS PAGE:7,835.003,000.001,923.00(B)(C)(D)(E)Quantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESPage 1 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/16/2019
CED Permit #:17-000389ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, CMP, 15"D-3435.00$ LFCulvert, CMP, 18"D-3541.00$ LFCulvert, CMP, 24"D-3656.00$ LFCulvert, CMP, 30"D-3778.00$ LFCulvert, CMP, 36"D-38130.00$ LFCulvert, CMP, 48"D-39190.00$ LFCulvert, CMP, 60"D-40270.00$ LFCulvert, CMP, 72"D-41350.00$ LFCulvert, Concrete, 8"D-4242.00$ LFCulvert, Concrete, 12"D-4348.00$ LFCulvert, Concrete, 15"D-4478.00$ LFCulvert, Concrete, 18"D-4548.00$ LFCulvert, Concrete, 24"D-4678.00$ LFCulvert, Concrete, 30"D-47125.00$ LFCulvert, Concrete, 36"D-48150.00$ LFCulvert, Concrete, 42"D-49175.00$ LFCulvert, Concrete, 48"D-50205.00$ LFCulvert, CPE Triple Wall, 6" D-5114.00$ LFCulvert, CPE Triple Wall, 8" D-5216.00$ LFCulvert, CPE Triple Wall, 12" D-5324.00$ LFCulvert, CPE Triple Wall, 15" D-5435.00$ LFCulvert, CPE Triple Wall, 18" D-5541.00$ LFCulvert, CPE Triple Wall, 24" D-5656.00$ LFCulvert, CPE Triple Wall, 30" D-5778.00$ LFCulvert, CPE Triple Wall, 36" D-58130.00$ LFCulvert, LCPE, 6"D-5960.00$ LFCulvert, LCPE, 8"D-6072.00$ LFCulvert, LCPE, 12"D-6184.00$ LFCulvert, LCPE, 15"D-6296.00$ LFCulvert, LCPE, 18"D-63108.00$ LFCulvert, LCPE, 24"D-64120.00$ LFCulvert, LCPE, 30"D-65132.00$ LFCulvert, LCPE, 36"D-66144.00$ LFCulvert, LCPE, 48"D-67156.00$ LFCulvert, LCPE, 54"D-68168.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 2 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/16/2019
CED Permit #:17-000389ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, LCPE, 60"D-69180.00$ LFCulvert, LCPE, 72"D-70192.00$ LFCulvert, HDPE, 6"D-7142.00$ LFCulvert, HDPE, 8"D-7242.00$ LFCulvert, HDPE, 12"D-7374.00$ LFCulvert, HDPE, 15"D-74106.00$ LFCulvert, HDPE, 18"D-75138.00$ LFCulvert, HDPE, 24"D-76221.00$ LFCulvert, HDPE, 30"D-77276.00$ LFCulvert, HDPE, 36"D-78331.00$ LFCulvert, HDPE, 48"D-79386.00$ LFCulvert, HDPE, 54"D-80441.00$ LFCulvert, HDPE, 60"D-81496.00$ LFCulvert, HDPE, 72"D-82551.00$ LFPipe, Polypropylene, 6"D-8384.00$ LFPipe, Polypropylene, 8"D-8489.00$ LFPipe, Polypropylene, 12"D-8595.00$ LFPipe, Polypropylene, 15"D-86100.00$ LFPipe, Polypropylene, 18"D-87106.00$ LFPipe, Polypropylene, 24"D-88111.00$ LFPipe, Polypropylene, 30"D-89119.00$ LFPipe, Polypropylene, 36"D-90154.00$ LFPipe, Polypropylene, 48"D-91226.00$ LFPipe, Polypropylene, 54"D-92332.00$ LFPipe, Polypropylene, 60"D-93439.00$ LFPipe, Polypropylene, 72"D-94545.00$ LFCulvert, DI, 6"D-9561.00$ LFCulvert, DI, 8"D-9684.00$ LFCulvert, DI, 12"D-97106.00$ LFCulvert, DI, 15"D-98129.00$ LFCulvert, DI, 18"D-99152.00$ LFCulvert, DI, 24"D-100175.00$ LFCulvert, DI, 30"D-101198.00$ LFCulvert, DI, 36"D-102220.00$ LFCulvert, DI, 48"D-103243.00$ LFCulvert, DI, 54"D-104266.00$ LFCulvert, DI, 60"D-105289.00$ LFCulvert, DI, 72"D-106311.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 3 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/16/2019
CED Permit #:17-000389ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESSpecialty Drainage ItemsDitching SD-19.50$ CYFlow Dispersal Trench (1,436 base+)SD-328.00$ LF 1,436.00101,716.00 French Drain (3' depth)SD-426.00$ LFGeotextile, laid in trench, polypropyleneSD-53.00$ SYMid-tank Access Riser, 48" dia, 6' deepSD-62,000.00$ EachPond Overflow SpillwaySD-716.00$ SYRestrictor/Oil Separator, 12"SD-81,150.00$ EachRestrictor/Oil Separator, 15"SD-91,350.00$ EachRestrictor/Oil Separator, 18"SD-101,700.00$ EachRiprap, placedSD-1142.00$ CYTank End Reducer (36" diameter)SD-121,200.00$ EachInfiltration pond testingSD-13125.00$ HRPermeable PavementSD-14Permeable Concrete SidewalkSD-15Culvert, Box __ ft x __ ftSD-16SUBTOTAL SPECIALTY DRAINAGE ITEMS:1,436.001,716.00(B)(C)(D)(E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention PondSF-1Each Detention TankSF-2Each Detention VaultSF-3Each Infiltration PondSF-4Each Infiltration TankSF-5Each Infiltration VaultSF-6Each Infiltration TrenchesSF-7Each Basic Biofiltration SwaleSF-8Each Wet Biofiltration SwaleSF-9Each WetpondSF-10Each WetvaultSF-11Each Sand FilterSF-12Each Sand Filter VaultSF-13Each Linear Sand FilterSF-14Each Proprietary FacilitySF-15Each Bioretention FacilitySF-161,500.00$ Each SUBTOTAL STORMWATER FACILITIES:(B)(C)(D)(E)Page 4 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/16/2019
CED Permit #:17-000389ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESWRITE-IN-ITEMS (INCLUDE ON-SITE BMPs)WI-1WI-2WI-3WI-4WI-5WI-6WI-7WI-8WI-9WI-10WI-11WI-12WI-13WI-14WI-15SUBTOTAL WRITE-IN ITEMS:DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:7,835.004,436.003,639.00SALES TAX @ 10%783.50443.60363.90DRAINAGE AND STORMWATER FACILITIES TOTAL:8,618.504,879.604,002.90(B) (C) (D) (E)Page 5 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 5/16/2019
Matveyev Short Plat Technical Information Report
Appendix C
Operations and Maintenance
Matveyev Short Plat Technical Information Report
Appendix D
Full WWHM2012 Output
WWHM2012
PROJECT REPORT
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General Model Information
Project Name:Storm Design
Site Name:
Site Address:
City:
Report Date:5/16/2019
Gage:Seatac
Data Start:1948/10/01
Data End:2009/09/30
Timestep:15 Minute
Precip Scale:1.000
Version Date:2018/10/10
Version:4.2.16
POC Thresholds
Low Flow Threshold for POC1:50 Percent of the 2 Year
High Flow Threshold for POC1:50 Year
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Landuse Basin Data
Predeveloped Land Use
Basin 1
Bypass:No
GroundWater:No
Pervious Land Use acre
C, Lawn, Mod 0.372
Pervious Total 0.372
Impervious Land Use acre
ROADS MOD 0.038
DRIVEWAYS MOD 0.04
SIDEWALKS FLAT 0.01
Impervious Total 0.088
Basin Total 0.46
Element Flows To:
Surface Interflow Groundwater
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Mitigated Land Use
Basin 1
Bypass:No
GroundWater:No
Pervious Land Use acre
C, Lawn, Mod 0.28
Pervious Total 0.28
Impervious Land Use acre
ROOF TOPS FLAT 0.15
DRIVEWAYS MOD 0.04
Impervious Total 0.19
Basin Total 0.47
Element Flows To:
Surface Interflow Groundwater
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Routing Elements
Predeveloped Routing
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Mitigated Routing
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Analysis Results
POC 1
+ Predeveloped x Mitigated
Predeveloped Landuse Totals for POC #1
Total Pervious Area:0.372
Total Impervious Area:0.088
Mitigated Landuse Totals for POC #1
Total Pervious Area:0.28
Total Impervious Area:0.19
Flow Frequency Method:Log Pearson Type III 17B
Flow Frequency Return Periods for Predeveloped. POC #1
Return Period Flow(cfs)
2 year 0.074499
5 year 0.10966
10 year 0.135944
25 year 0.172646
50 year 0.202577
100 year 0.234778
Flow Frequency Return Periods for Mitigated. POC #1
Return Period Flow(cfs)
2 year 0.097488
5 year 0.134095
10 year 0.160649
25 year 0.196916
50 year 0.225955
100 year 0.256773
Annual Peaks
Annual Peaks for Predeveloped and Mitigated. POC #1
Year Predeveloped Mitigated
1949 0.122 0.148
1950 0.121 0.138
1951 0.070 0.088
1952 0.041 0.058
1953 0.038 0.062
1954 0.059 0.079
1955 0.063 0.087
1956 0.067 0.083
1957 0.083 0.108
1958 0.051 0.074
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1959 0.046 0.065
1960 0.077 0.094
1961 0.062 0.085
1962 0.040 0.064
1963 0.068 0.088
1964 0.062 0.075
1965 0.088 0.113
1966 0.047 0.064
1967 0.119 0.135
1968 0.107 0.139
1969 0.079 0.102
1970 0.068 0.091
1971 0.083 0.111
1972 0.110 0.133
1973 0.037 0.055
1974 0.087 0.109
1975 0.087 0.111
1976 0.065 0.083
1977 0.060 0.077
1978 0.076 0.095
1979 0.071 0.114
1980 0.154 0.166
1981 0.067 0.096
1982 0.129 0.159
1983 0.080 0.101
1984 0.049 0.070
1985 0.067 0.096
1986 0.069 0.088
1987 0.072 0.113
1988 0.035 0.063
1989 0.055 0.085
1990 0.222 0.246
1991 0.160 0.182
1992 0.057 0.071
1993 0.041 0.055
1994 0.033 0.054
1995 0.058 0.084
1996 0.115 0.123
1997 0.081 0.103
1998 0.070 0.085
1999 0.179 0.221
2000 0.074 0.099
2001 0.058 0.090
2002 0.110 0.139
2003 0.105 0.120
2004 0.162 0.202
2005 0.066 0.087
2006 0.066 0.083
2007 0.207 0.224
2008 0.151 0.175
2009 0.091 0.111
Ranked Annual Peaks
Ranked Annual Peaks for Predeveloped and Mitigated. POC #1
Rank Predeveloped Mitigated
1 0.2225 0.2460
2 0.2068 0.2245
3 0.1795 0.2207
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4 0.1624 0.2017
5 0.1600 0.1820
6 0.1537 0.1752
7 0.1515 0.1660
8 0.1294 0.1592
9 0.1225 0.1483
10 0.1211 0.1390
11 0.1194 0.1390
12 0.1147 0.1380
13 0.1102 0.1352
14 0.1100 0.1334
15 0.1066 0.1229
16 0.1049 0.1197
17 0.0914 0.1144
18 0.0877 0.1134
19 0.0872 0.1126
20 0.0868 0.1108
21 0.0833 0.1106
22 0.0832 0.1106
23 0.0807 0.1089
24 0.0802 0.1079
25 0.0791 0.1027
26 0.0769 0.1019
27 0.0759 0.1012
28 0.0740 0.0989
29 0.0724 0.0965
30 0.0710 0.0962
31 0.0701 0.0948
32 0.0700 0.0935
33 0.0692 0.0913
34 0.0682 0.0897
35 0.0677 0.0882
36 0.0674 0.0881
37 0.0673 0.0880
38 0.0665 0.0873
39 0.0664 0.0868
40 0.0662 0.0854
41 0.0654 0.0852
42 0.0629 0.0846
43 0.0622 0.0844
44 0.0617 0.0827
45 0.0601 0.0827
46 0.0585 0.0825
47 0.0584 0.0793
48 0.0577 0.0775
49 0.0570 0.0750
50 0.0550 0.0744
51 0.0510 0.0710
52 0.0488 0.0701
53 0.0474 0.0647
54 0.0457 0.0643
55 0.0411 0.0637
56 0.0406 0.0626
57 0.0402 0.0624
58 0.0384 0.0584
59 0.0368 0.0552
60 0.0347 0.0550
61 0.0333 0.0539