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HomeMy WebLinkAboutGreenleaf II TIRTECHNICAL INFORMATION REPORT
FOR
GREENLEAF 2
Prepared for:
Conner Homes
12600 SE 38th St, Suite 250
Bellevue, WA 98004
Prepared by:
ESM Consulting Engineers
33400 8th Avenue S, Suite 205
Federal Way, WA 98003
February 15, 2016 Job No. 258-044-013
Approved By:
City of Renton Date
i
TABLE OF CONTENTS
1. PROJECT OVERVIEW ................................................................................................................................................................................. 1-1
2. CONDITIONS AND REQUIREMENTS SUMMARY..................................................................................................... 2-1
3. OFF-SITE ANALYSIS .................................................................................................................................................................................... 3-1
4. FLOW CONTROL & WATER QUALITY FACILITY ANALYSIS AND DESIGN ..............................4-1
5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ............................................................................................... 5-1
6. SPECIAL REPORTS AND STUDIES ............................................................................................................................................ 6-1
7. OTHER PERMITS .............................................................................................................................................................................................. 7-1
8. CSWPPP ANALYSIS AND DESIGN ............................................................................................................................................. 8-1
9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ....9-1
10. OPERATIONS AND MAINTENANCE MANUAL ............................................................................................................. 10-1
LIST OF FIGURES
1.1 Vicinity Map
1.2 Existing Site Conditions
1.3 Proposed Site Conditions
1.4 Soils Map
3.1 KCGIS Parcel Reports/Environmental Hazards
3.2 Offsite Analysis Downstream Flowpath
4.1 Pond Existing Tributary Area Map
4.2 Pond Developed Tributary Area Map
APPENDIX
Appendix A: KCRTS Pond Sizing Output
Appendix B: Geotech Report and Summary Letter prepared by Earth Solutions NW
Appendix C: Critical Area Report for Panther Lake, prepared by Sewall Wetland Consulting, Inc.
Appendix D Operations and Maintenance Manual
1-1
1. PROJECT OVERVIEW
The original Greenleaf project is a 34-lot plat located on the west side of 108th Ave SE, just
north of SE 192nd St, in the City of Renton, WA. The proposed Greenleaf 2 project is an
extension of the original project, consisting of a 3-lot short plat on parcel 3223059088,
north of SE 188th Street, on 0.53 acres. See Figure 1.1 for the Greenleaf Vicinity Map.
Structures on the existing site have been demolished and the parcel is generally grassed
with trees. The existing site is moderately sloped at approximately 5 percent sloping
generally to the southwest. See Figure 1.2 for the Existing Site Conditions.
The Greenleaf 2 0.53 acre project site consists of 3 residential lots that will have new
single-family dwelling units. 31 lots were developed under a previously approved permit,
and 3 lots were added later. For access, the original project created a new intersection off
108th Ave SE at the northeast corner of the project site. There is also an access point to
108th Ave SE created at the midpoint of the project site, through an access easement of
the adjoining property. The Greenleaf 2 project will access off of this second access point
to 108th Ave SE, now called SE 188th Street. See Figure 1.3 for the Proposed Site
Conditions.
According to the Geotech Report prepared by Earth Solutions NW and the Summary Letter
for Greenleaf 2, the overall site is underlain primarily by native soils consisting of dense
glacial till and silty sand with gravel. Additionally, according to the USDA NRCS soil
mapping service, the entire site is underlain by Alderwood Gravelly Sandy Loam (a till soil),
which varies from 5-30%. See Figure 1.4 for the Soils Map.
A stormwater detention pond located in the southwest portion of the overall site was
previously approved to meet the overall project’s stormwater detention requirements. The
detention pond was designed with a factor of safety and has sufficient capacity to
accommodate the proposed Greenleaf 2 project. See Section 4 for more information.
A Kirstar Perk Filter vault that follows the detention pond treats the original Greenleaf
project. Since the proposed three lot addition does not create pollution generating areas,
no additional water quality treatment is proposed for the Greenleaf 2 3 lot addition. The
detention pond/Kristar Perk Filter discharges to the west to Panther Creek, a well defined
stream.
Based on the City of Renton’s Flow Control Application Map, the project site is in the Flow
Control Duration Standard (Forested Conditions) area. The overall project will be subject
to Full Drainage Review per the City of Renton 2009 Surface Water Design Manual
Amendments and the 2009 King County Surface Water Design Manual (2009 KCSWDM).
The City of Renton 2009 Surface Water Design Manual Amendment and the 2009
KCSWDM will collectively be referred to as the “2009 Surface Water Design Manual”.
1-2
Figure 1.1
Greenleaf Vicinity Map
1-3
Figure 1.2
Existing Site Conditions
1-4
Figure 1.3
Proposed Site Conditions
1-5
Figure 1.4
Soils Map
2-1
2. CONDITIONS AND REQUIREMENTS SUMMARY
Review of the 8 Core Requirements and 6 Special Requirements
This section describes how the project will meet the 2009 Surface Water Design Manual’s
Core and Special Requirements.
Core Requirement No. 1 Discharge at the Natural Location
In the existing conditions, the site drains to the west, towards Panther Creek. The original
project’s detention pond discharges to the west corner of the site, which is the natural
discharge location for the project site.
Core Requirement No. 2 Off-site Analysis
A Level 1 Downstream Analysis was performed by ESM on September 19, 2013 for the
original project, which also applies to the proposed Greenleaf 2 project. See Section 3 for
the offsite analysis.
Core Requirement No. 3 Flow Control
Based on the City of Renton’s Flow Control Application Map, the project site is in the Flow
Control Duration Standard (Forested Conditions) area. See Section 4 for Flow Control
Analysis and Calculations.
Core Requirement No. 4 Conveyance System
The stormwater drainage conveyance system has been sized to convey the 25 year
design storm event and to contain the 100 year design storm event as part of the original
Greenleaf project. The existing conveyance system has sufficient capacity to
accommodate the proposed Greenleaf 2 project. See Section 5 and Appendix A.
Core Requirement No. 5 Erosion and Sediment Control
Erosion and sediment controls will be provided to prevent, to the maximum extent
possible, the transport of sediment from the project site to downstream drainage facilities,
water resources, and adjacent properties. The Temporary Erosion and Sedimentation
Control (TESC) plan for the Greenleaf 2 project shows silt fence and a construction
entrance to maintain erosion and sediment control.
Core Requirement No. 6 Maintenance and Operations
The Operations and Maintenance Manual for the overall project is provided in Appendix D.
Core Requirement No. 7 Financial Guarantees and Liability
All drainage facilities constructed for the project comply with the financial guarantee
requirements is provided in the City of Renton Bond Quantities Worksheet in Section 9 of
this report.
Core Requirement No. 8 Water Quality
The site does not create pollution generating areas; therefore no water quality treatment is
required or proposed. See Section 4 for more information.
2-2
Special Requirement No. 1 Other Adopted Area-Specific Requirements
There are no master drainage plans, basin plans, salmon conservation plans, stormwater
compliance plans, flood hazard reduction plan updates, or shared facility drainage plans
for this project. Special Requirement No. 1 does not apply.
Special Requirement No. 2 Flood Hazard Area Delineation
There is no 100-year flood plain associated with a large body of water (i.e. lake or stream)
on the site or adjacent to the site. Special Requirement No. 2 does not apply.
Special Requirement No. 3 Flood Protection Facilities
The project lies outside any pre-defined flood plain. Special Requirement No. 3 does not
apply.
Special Requirement No. 4 Source Control
The project is a residential short plat and is not subject to this requirement. Special
Requirement No. 4 does not apply.
Special Requirement No. 5 Oil Control
The project does not have a “high-use site characteristic” and is not a redevelopment of a
high-use site. Special Requirement No. 5 does not apply.
Special Requirement No. 6 Aquifer Protection Area
According to the “Groundwater Protection Areas in the City of Renton” map, the project site
is not in an Aquifer Protection Area. Special Requirement No. 6 does not apply.
3-1
3.OFF-SITE ANALYSIS
Task 1: Study Area Definition and Maps
Figure 1.2 shows the existing site conditions. Figure 3.2 shows the extent of offsite
analysis and the downstream flow path from the site.
Task 2: Resource Review
·Flow Control Map
According to the City of Renton Flow Control Application Map, the site is in a Flow
Control Duration Standard (Forested Conditions) area.
·Soil Survey Map
·According to the Geotech Report prepared by Earth Solutions NW and the
Summary Letter for Greenleaf 2, the overall site is underlain primarily by native soils
consisting of dense glacial till and silty sand with gravel. Additionally, according to
the USDA NRCS soil mapping service, the entire site is underlain by Alderwood
Gravelly Sandy Loam (a till soil), which varies from 5-30%. See Figure 1.4 for the
Soils Map.
·King County iMap
According to the King County GIS Viewer (iMap), the project is NOT in any of the
following areas:
o Streams & 100 year floodplains
o Seismic Hazard Areas
o Coal Mine Hazard Areas
o Wetlands
Four wetlands were found and delineated on site, according to the
Critical Area Report for Greenleaf, prepared by Sewall Wetland Consulting
Inc. All four wetlands require a 25 foot standard buffer. In the southeast
corner of the site there is a class 4 stream and an offsite wetland whose
buffer is on site. Additionally, Panther Creek is a Class 2 stream that is
off-site to the west of the project area that has a buffer that extends on
site.
o Landslide Hazard Areas
According to the City of Renton regulations and criteria for Landslide
Hazard Areas, the west portions of the site (over 40%) are classified as a
landslide hazard area (although are not mapped as such in King County
iMap). According to the Geotechnical Report by Earth Solutions NW, the
slope is underlain by glacial till, therefore the overall global stability of the
slope areas can be characterized as moderate. Slope stabilization,
erosion control measures, and buffer zones will be utilized.
o Erosion Hazard Areas
According to King County iMap, a portion of the north section of the
project is located in an Erosion Hazard Area. According to the
Geotechnical Report by Earth Solutions NW, the planned development
will not increase the erosion hazard at the site, provided appropriate Best
Management Practices are implemented during the earthwork and
development activities.
3-2
·City of Renton 2009 Surface Water Manual Amendments
According to Reference 11 in the City of Renton 2009 Surface Water Design
Manual Amendments, the project is NOT in any of the following areas:
o Aquifer Protection Areas
o Groundwater Protection Areas
·Road Drainage Problems
None noted
·Wetlands Inventory
Four wetlands were found and delineated on site, according to the Critical Area
Report for Greenleaf, prepared by Sewall Wetland Consulting Inc. All four wetlands
require a 25 foot standard buffer. In the southeast corner of the site there is a
class 4 stream and an offsite wetland whose buffer is on site. Additionally, Panther
Creek is a Class 2 stream that is off-site to the west of the project area that has a
buffer that extends on site. Buffer averaging and mitigation Plan has been
approved as part of the original permit approval.
·Migrating River Study
None noted
·Downstream Drainage Complaints
There are no drainage complaints in the downstream flow path within the last 10
years. The project site will be releasing at the Flow Control Duration Standards,
Forested Site Conditions, and will not aggravate or impact any downstream flow
paths.
3-3
Figure 3.1
KCGIS Parcel Report/Environmental Hazards
3-4
Task 3: Field Inspection (Level 1 Inspection)
A Level 1 Downstream Analysis was completed by ESM Consulting Engineers on
September 19, 2013. The project is located in the Panther Creek Subbasin. The property
directly to the north of the project site is fully developed, with a combined water
quality/detention pond. No offsite runoff is anticipated to enter the project site from this
development. At the south boundary of the site is Wetland D and a small stream, runoff
from the south part of the project site enters here. No offsite runoff from the south is
anticipated, as it will be intercepted by the small stream. 108th Ave SE is a fully developed
roadway with curb and gutter, catch basins, and piped storm drainage. Although the road
sits higher than the east portions of the site, all runoff from the road is captured by this
storm system and conveyed elsewhere. There are three parcels and a portion of another
that are in between the project boundary and 108th Ave SE. These parcels will drain onto
the project. These areas will be captured and routed to the proposed detention pond.
This flow will not be detained, but will be treated for water quality.
Task 4: Drainage Description and Problem Descriptions
According to iMap, the entire project site is in the Black River (King County WRIA #9) basin.
Black River is located to the northwest of the project site, and is tributary to the Duwamish
Waterway.
In general, the site flows from the east to the west. The low point of the site is located
roughly in the southwest portion of the site. The existing site sheet flows to the west and
discharges to Panther Creek, or to the small stream at the south boundary of the project
which is tributary to Panther Creek. Panther Creek is approximately 40’ vertically below the
project site. Once in Panther Creek, the flows continue to the north in a well defined
stream. Due to private property, fences, and elevation, Panther Creek was not able to be
observed downstream. However, Panther Creek is a large, well defined channel, with no
anticipated drainage problems.
The project discharges to Panther Creek at a lower rate than currently existing. It will
match the historic predeveloped flows (Flow Control Duration Standards, Forested Site
Conditions), which are till forested conditions. The current site is about half lawn, 2
residences with associated outbuildings, and gravel driveways, therefore it is currently
discharging more than historic predeveloped flows.
Task 5: Mitigation of Existing or Potential Problems
Runoff from the majority of the site is collected in a piped storm system and directed to
the proposed Kristar Perk Filter vault/detention pond. The runoff from the overall site
discharges at the Flow Control Duration Standard (Forested Conditions) into Panther
Creek, to the west.
3-5
Figure 3.2
Offsite Analysis Downstream Flowpath
4-1
4. FLOW CONTROL & WATER QUALITY FACILITY ANALYSIS AND DESIGN
4.1 Existing Site Hydrology
The original existing site consisted of 2 single-family dwellings with associated gravel
driveways, along with a few detached structures. All structures on site were demolished.
The developable portion of the original existing site was moderately sloped (slopes between
6-15%) and slopes down generally from the east side of the property towards the west. At
the west edge of the property, the site becomes very steep (15%+) and slopes down
towards Panther Creek. The pervious portions of the parcels around the buildings are
generally lawn, while there is significant forested area on the west sides of most parcels.
According to the Geotech Report prepared by Earth Solutions NW and the Summary Letter
for Greenleaf 2, the overall site is underlain primarily by native soils consisting of dense
glacial till and silty sand with gravel. Additionally, according to the USDA NRCS soil
mapping service, the entire site is underlain by Alderwood Gravelly Sandy Loam (a till soil),
which varies from 5-30%. See Figure 1.4 for the Soils Map. Till soils are incapable of
infiltration, therefore Till soils are used in the KCRTS model. To meet the City of Renton’s
Flow Control Duration Standard (Forested Conditions), the entire predeveloped area is
modeled as Till Forest.
Approximately 1.45 acres of upstream area drains onto the site from the east, in between the
project site and 108th Ave SE. See Table 4.3 in Section 4.2.
TABLE 4.1
Pre-Developed Tributary Area
SUBBASIN TOTAL AREA
(Ac)
TILL FOREST
(Ac)
Greenleaf 8.04 8.04
Greenleaf 2 0.53 0.53
TOTAL 8.57 8.57
4.2 Developed Site Hydrology
The project will create 3 single family lots with associated sidewalk, driveways, roof areas,
and landscaped yards. Building rooftops and impervious areas (driveway, porch) were
estimated as 65% impervious, which is 10% below the maximum impervious area (75%)
allowed by the City of Renton Zoning Code 4-2-110A for R-8 zoned lots. The 10% reduction
in impervious area satisfies the impervious Lot BMP requirements. The sidewalk was
estimated at 1% of the total project area.
TABLE 4.2
Developed Pond Detained Area
SUBBASIN TOTAL
AREA
(Ac)
IMPERV.
AREA (Ac)
TILL
GRASS
(Ac)
Greenleaf 7.44 3.62 3.82
Greenleaf 2 0.53 0.35 0.18
Offsite Area 0.91 0.17 0.74
TOTAL 8.88 4.14 4.74
The original detention pond is located in the south western corner of the site. The detained
runoff will be discharged to the west to Panther Creek, a well defined stream.
4-2
TABLE 4.3
Bypass Area
SUBBASIN TOTAL
AREA
(Ac)
IMPERV.
AREA (Ac)
TILL
GRASS
(Ac)
Three Lot Addition
Bypass Area 0.60 0.52 0.08
TOTAL 0.60 0.52 0.08
See Figure 4.1 for a visual representation of the Developed Tributary Area.
4.3 Performance Standards
Performance Standards for flow control design use the KCRTS Methodology with hourly time
steps as described in Section 4.4 below. Runoff files for the existing, and proposed
conditions were created using the historic KCRTS time series data sets for the SeaTac
Rainfall Region with a Correction Factor of 1.0.
4.4 Flow Control System
The detention pond was sized per the requirements in the 2009 Surface Water Design
Manual. Per the City of Renton’s Flow Control Application Map, the project site is in the Flow
Control Duration Standard (Forested Conditions) area. This standard requires the site to
match the durations of high flows at their predevelopment levels for all flows from one-half of
the 2 year peak flow up to the 50 year peak flow.
The offsite flows being routed through the pond are not subject to flow control, therefore the
offsite flows was added to the predeveloped and developed flows.
Predevcombined = predev (onsite) + offsite flows
Devcombined = dev (onsite) + offsite flows
The target flows are calculated as follows:
50% 2 year: 50% of the 2 year from predev (onsite) + offsite 2 year
50 year: predev 50 year + offsite 50 year
The pond’s inflow was modeled using the devcombined time series and the pond’s outflow
was the rdout time series. This rdout time series matches the Flow Control Duration
Standard (Forested Conditions).
KCRTS v6.0 was used to design the pond. Procedures and design criteria specified in the
2009 Surface Water Design Manual were followed for the hydrologic and hydraulic
modeling. The KCRTS pond sizing output is included in Appendix A.
The KCRTS output models the original required detention volume as 65,115 cubic feet of
storage, with 8.75 feet of detention. The as-built pond documentation shows 69,099 cubic
feet of storage, which results in an approximate safety factor of 6%. With the additional
Greenleaf 2 project, the required detention volume increases to 69,044 cubic feet, remaining
less than the provided as-built volume. The control structure orifices will remain at the same
elevations and slightly change in size as shown in Appendix A.
4-3
Figure 4.1
Pond Tributary Area
4-4
Figure 4.2
Pond Developed Tributary Area
4-5
4.5 Water Quality Facility
The proposed Greenleaf 2 project does not create pollution generating areas. The rooftops,
patios, landscaped areas and sidewalk are considered clean runoff, and the proposed
driveways are a negligible addition. Furthermore, the original project treatment release rate
was calculated at 0.202 cfs and the Kristar Perk Filter treatment flowrate provided is 0.33 cfs.
Therefore, the proposed Greenleaf 2 project does not require additional water quality
treatment.
5-1
5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
A conveyance analysis was performed for the mainline storm drainage systems and the
rooftop conveyance systems which have sufficient capacity to accommodate the
proposed Greenleaf 2 project. See conveyance documentation in Appendix A.
6-1
6. SPECIAL REPORTS AND STUDIES
Following are the reports and studies referenced for the proposed development:
·Geotechnical Engineering Report, by Earth Solutions NW, LLC, dated September
23, 2013 and Summary Letter for Greenleaf 2/Kohr Short Plat dated February 9,
2016. (Appendix B)
·Critical Area Report for Greenleaf, by Sewall Wetland Consulting Inc, dated January
28, 2014. (Appendix C)
·Greenleaf Technical Information Report, by ESM Consulting Engineers, LLC dated
January 22, 2015. (Excerpts in Appendix A and D)
7-1
7. OTHER PERMITS
The National Pollutant Discharge Elimination System (NPDES) permit was prepared with
the original construction plans. Since this project is less than one acre, an additional
NPDES permit is not required.
This project will also require building permits.
8-1
8. CSWPPP ANALYSIS AND DESIGN
Silt fence and a construction entrance in the construction of the three lot addition in order
to maintain erosion and sediment control.
9-1
9.BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF
COVENANT
The Bond Quantities Worksheet is provided in this Section. Facility Summaries and
Declaration of Covenant will be provided at a later date.
Site Improvement Bond Quantity Worksheet S15 Web date: 04/03/2015
Department of Permitting & Environmental Review
35030 SE Douglas Street, Suite 210
Snoqualmie, Washington 98065-9266
206-296-6600 TTY Relay 711
Project Name:Date:
Location:Project No.:
Activity No.:
Note: All prices include labor, equipment, materials, overhead and
Clearing greater than or equal to 5,000 board feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area
or from local sources if not included in the RS Means database.
_____________yes __________________no
If yes,
Forest Practice Permit Number:
(RCW 76.09)
Page 1 of 9
Greenleaf 2
18661 108th Avenue SE, Renton, WA
For alternate formats, call 206-296-6600.
__________________
2/15/2016
bondquantityworksheet.xls
Unit prices updated: 3/2/2015
Version: 3/2/2015
Report Date: 2/15/2016
Site Improvement Bond Quantity Worksheet S15 Web date: 04/03/2015
Unit # of
Reference #Price Unit Quantity Applications Cost
EROSION/SEDIMENT CONTROL Number
Backfill & compaction-embankment ESC-1 6.00$CY 260 1 1560
Check dams, 4" minus rock ESC-2 SWDM 5.4.6.3 80.00$Each
Crushed surfacing 1 1/4" minus ESC-3 WSDOT 9-03.9(3)95.00$CY
Ditching ESC-4 9.00$CY
Excavation-bulk ESC-5 2.00$CY
Fence, silt ESC-6 SWDM 5.4.3.1 1.50$LF 650 1 975
Fence, Temporary (NGPE)ESC-7 1.50$LF
Hydroseeding ESC-8 SWDM 5.4.2.4 0.80$SY 800 1 640
Jute Mesh ESC-9 SWDM 5.4.2.2 3.50$SY
Mulch, by hand, straw, 3" deep ESC-10 SWDM 5.4.2.1 2.50$SY
Mulch, by machine, straw, 2" deep ESC-11 SWDM 5.4.2.1 2.00$SY
Piping, temporary, CPP, 6"ESC-12 12.00$LF
Piping, temporary, CPP, 8"ESC-13 14.00$LF
Piping, temporary, CPP, 12"ESC-14 18.00$LF
Plastic covering, 6mm thick, sandbagged ESC-15 SWDM 5.4.2.3 4.00$SY
Rip Rap, machine placed; slopes ESC-16 WSDOT 9-13.1(2)45.00$CY
Rock Construction Entrance, 50'x15'x1'ESC-17 SWDM 5.4.4.1 1,800.00$Each 1 1 1800
Rock Construction Entrance, 100'x15'x1'ESC-18 SWDM 5.4.4.1 3,200.00$Each
Sediment pond riser assembly ESC-19 SWDM 5.4.5.2 2,200.00$Each
Sediment trap, 5' high berm ESC-20 SWDM 5.4.5.1 19.00$LF
Sed. trap, 5' high, riprapped spillway berm section ESC-21 SWDM 5.4.5.1 70.00$LF
Seeding, by hand ESC-22 SWDM 5.4.2.4 1.00$SY
Sodding, 1" deep, level ground ESC-23 SWDM 5.4.2.5 8.00$SY
Sodding, 1" deep, sloped ground ESC-24 SWDM 5.4.2.5 10.00$SY
TESC Supervisor ESC-25 110.00$HR
Water truck, dust control ESC-26 SWDM 5.4.7 140.00$HR
WRITE-IN-ITEMS **** (see page 9)
Each
ESC SUBTOTAL:4,975.00$
30% CONTINGENCY & MOBILIZATION:1,492.50$
ESC TOTAL:6,467.50$
COLUMN:A
Page 2 of 9
bondquantityworksheet.xls
Unit prices updated: 3/2/2015
Version: 3/2/2015
Report Date: 2/15/2016
Site Improvement Bond Quantity Worksheet Web date: 04/03/2015
Existing Future Public Private
Right-of-Way Right of Way Improvements
Unit Price Unit Quant.Cost Quant.Cost Quant.Cost
GENERAL ITEMS No.
Backfill & Compaction- embankment GI - 1 6.00$CY 260 1,560.00
Backfill & Compaction- trench GI - 2 9.00$CY
Clear/Remove Brush, by hand GI - 3 1.00$SY
Clearing/Grubbing/Tree Removal GI - 4 10,000.00$Acre
Excavation - bulk GI - 5 2.00$CY 510 1,020.00
Excavation - Trench GI - 6 5.00$CY
Fencing, cedar, 6' high GI - 7 20.00$LF
Fencing, chain link, vinyl coated, 6' high GI - 8 20.00$LF
Fencing, chain link, gate, vinyl coated, 20'GI - 9 1,400.00$Each
Fencing, split rail, 3' high GI - 10 15.00$LF
Fill & compact - common barrow GI - 11 25.00$CY
Fill & compact - gravel base GI - 12 27.00$CY
Fill & compact - screened topsoil GI - 13 39.00$CY
Gabion, 12" deep, stone filled mesh GI - 14 65.00$SY
Gabion, 18" deep, stone filled mesh GI - 15 90.00$SY
Gabion, 36" deep, stone filled mesh GI - 16 150.00$SY
Grading, fine, by hand GI - 17 2.50$SY
Grading, fine, with grader GI - 18 2.00$SY 2500 5,000.00
Monuments, 3' long GI - 19 250.00$Each
Sensitive Areas Sign GI - 20 7.00$Each
Sodding, 1" deep, sloped ground GI - 21 8.00$SY
Surveying, line & grade GI - 22 850.00$Day
Surveying, lot location/lines GI - 23 1,800.00$Acre
Traffic control crew ( 2 flaggers )GI - 24 120.00$HR
Trail, 4" chipped wood GI - 25 8.00$SY
Trail, 4" crushed cinder GI - 26 9.00$SY
Trail, 4" top course GI - 27 12.00$SY
Wall, retaining, concrete GI - 28 55.00$SF
Wall, rockery GI - 29 15.00$SF
Page 3 of 9 SUBTOTAL 7,580.00
& Drainage Facilities
*KCC 27A authorizes only one bond reduction.
bondquantityworksheet.xls
Unit prices updated: 03/02/2015
Version: 03/02/2015
Report Date: 2/15/2016
Site Improvement Bond Quantity Worksheet Web date: 04/03/2015
Existing Future Public
Right-of-way Right of Way Improvements
Unit Price Unit Quant.Cost Quant.Cost Quant.Cost
ROAD IMPROVEMENT No.
AC Grinding, 4' wide machine < 1000sy RI - 1 30.00$SY
AC Grinding, 4' wide machine 1000-2000syRI - 2 16.00$SY
AC Grinding, 4' wide machine > 2000sy RI - 3 10.00$SY
AC Removal/Disposal RI - 4 35.00$SY
Barricade, type III ( Permanent )RI - 6 56.00$LF
Curb & Gutter, rolled RI - 7 17.00$LF
Curb & Gutter, vertical RI - 8 12.50$LF
Curb and Gutter, demolition and disposal RI - 9 18.00$LF 20 360.00
Curb, extruded asphalt RI - 10 5.50$LF
Curb, extruded concrete RI - 11 7.00$LF
Sawcut, asphalt, 3" depth RI - 12 1.85$LF
Sawcut, concrete, per 1" depth RI - 13 3.00$LF
Sealant, asphalt RI - 14 2.00$LF
Shoulder, AC, ( see AC road unit price ) RI - 15 -$SY
Shoulder, gravel, 4" thick RI - 16 15.00$SY
Sidewalk, 4" thick RI - 17 38.00$SY 70 2,660.00
Sidewalk, 4" thick, demolition and disposal RI - 18 32.00$SY
Sidewalk, 5" thick RI - 19 41.00$SY
Sidewalk, 5" thick, demolition and disposal RI - 20 40.00$SY
Sign, handicap RI - 21 85.00$Each
Striping, per stall RI - 22 7.00$Each
Striping, thermoplastic, ( for crosswalk ) RI - 23 3.00$SF
Striping, 4" reflectorized line RI - 24 0.50$LF
Page 4 of 9 SUBTOTAL 3,020.00
& Drainage Facilities
Private
*KCC 27A authorizes only one bond reduction.
bondquantityworksheet.xls
Unit prices updated: 03/02/2015
Version: 03/02/2015
Report Date: 2/15/2016
Site Improvement Bond Quantity Worksheet Web date: 04/03/2015
Existing Future Public Private
Right-of-way Right of Way Improvements
Unit Price Unit Quant.Cost Quant.Cost Quant.Cost
ROAD SURFACING No. (4" Rock = 2.5 base & 1.5" top course) 9 1/2" Rock= 8" base & 1.5" top course)
Additional 2.5" Crushed Surfacing RS - 1 3.60$SY
HMA 1/2" Overlay, 1.5"RS - 2 14.00$SY
HMA 1/2" Overlay 2"RS - 3 18.00$SY
HMA Road, 2", 4" rock, First 2500 SY RS - 4 28.00$SY
HMA Road, 2", 4" rock, Qty. over 2500 SY RS - 5 21.00$SY
HMA Road, 3", 9 1/2" Rock, First 2500 SY RS - 6 35.00$SY
HMA Road, 3", 9 1/2" Rock, Qty Over 2500 SYRS - 7 42.00$SY
Not Used RS - 8
Not Used RS - 9
HMA Road, 6" Depth, First 2500 SY RS - 10 33.10$SY
HMA Road, 6" Depth, Qty. Over 2500 SY RS - 11 30.00$SY
HMA 3/4" or 1", 4" Depth RS - 12 20.00$SY
Gravel Road, 4" rock, First 2500 SY RS - 13 15.00$SY
Gravel Road, 4" rock, Qty. over 2500 SY RS - 14 10.00$SY
PCC Road (Add Under Write-Ins w/Design)RS - 15
Thickened Edge RS - 17 8.60$LF
Page 5 of 9 SUBTOTAL
& Drainage Facilities
*KCC 27A authorizes only one bond reduction.
bondquantityworksheet.xls
Unit prices updated: 03/02/2015
Version: 03/02/2015
Report Date: 2/15/2016
Site Improvement Bond Quantity Worksheet Web date: 04/03/2015
Existing Future Public Private
Right-of-way Right of Way Improvements
Unit Price Unit Quant.Cost Quant.Cost Quant.Cost
DRAINAGE (CPP = Corrugated Plastic Pipe, N12 or Equivalent)
Access Road, R/D D - 1 21.00$SY
Bollards - fixed D - 2 240.74$Each
Bollards - removable D - 3 452.34$Each
* (CBs include frame and lid)
CB Type I D - 4 1,500.00$Each
CB Type IL D - 5 1,750.00$Each
CB Type II, 48" diameter D - 6 2,300.00$Each
for additional depth over 4'D - 7 480.00$FT
CB Type II, 54" diameter D - 8 2,500.00$Each
for additional depth over 4'D - 9 495.00$FT
CB Type II, 60" diameter D - 10 2,800.00$Each
for additional depth over 4'D - 11 600.00$FT
CB Type II, 72" diameter D - 12 3,600.00$Each
for additional depth over 4'D - 13 850.00$FT
Through-curb Inlet Framework (Add)D - 14 400.00$Each
Cleanout, PVC, 4"D - 15 150.00$Each
Cleanout, PVC, 6"D - 16 170.00$Each 3 510.00
Cleanout, PVC, 8"D - 17 200.00$Each
Culvert, PVC, 4"D - 18 10.00$LF
Culvert, PVC, 6"D - 19 13.00$LF 60 780.00
Culvert, PVC, 8"D - 20 15.00$LF
Culvert, PVC, 12"D - 21 23.00$LF
Culvert, CMP, 8"D - 22 19.00$LF
Culvert, CMP, 12"D - 23 29.00$LF
Culvert, CMP, 15"D - 24 35.00$LF
Culvert, CMP, 18"D - 25 41.00$LF
Culvert, CMP, 24"D - 26 56.00$LF
Culvert, CMP, 30"D - 27 78.00$LF
Culvert, CMP, 36"D - 28 130.00$LF
Culvert, CMP, 48"D - 29 190.00$LF
Culvert, CMP, 60"D - 30 270.00$LF
Culvert, CMP, 72"D - 31 350.00$LF
Page 6 of 9 SUBTOTAL 1,290.00
& Drainage Facilities
For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.
*KCC 27A authorizes only one bond reduction.
bondquantityworksheet.xls
Unit prices updated: 03/02/2015
Version: 03/02/2015
Report Date: 2/15/2016
Site Improvement Bond Quantity Worksheet Web date: 04/03/2015
Existing Future Public Private
Right-of-way Right of Way Improvements
DRAINAGE CONTINUED
No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost
Culvert, Concrete, 8"D - 32 25.00$LF
Culvert, Concrete, 12"D - 33 36.00$LF
Culvert, Concrete, 15"D - 34 42.00$LF
Culvert, Concrete, 18"D - 35 48.00$LF
Culvert, Concrete, 24"D - 36 78.00$LF
Culvert, Concrete, 30"D - 37 125.00$LF
Culvert, Concrete, 36"D - 38 150.00$LF
Culvert, Concrete, 42"D - 39 175.00$LF
Culvert, Concrete, 48"D - 40 205.00$LF
Culvert, CPP, 6"D - 41 14.00$LF
Culvert, CPP, 8"D - 42 16.00$LF
Culvert, CPP, 12"D - 43 24.00$LF
Culvert, CPP, 15"D - 44 35.00$LF
Culvert, CPP, 18"D - 45 41.00$LF
Culvert, CPP, 24"D - 46 56.00$LF
Culvert, CPP, 30"D - 47 78.00$LF
Culvert, CPP, 36"D - 48 130.00$LF
Ditching D - 49 9.50$CY
Flow Dispersal Trench (1,436 base+)D - 50 28.00$LF
French Drain (3' depth)D - 51 26.00$LF
Geotextile, laid in trench, polypropylene D - 52 3.00$SY
Mid-tank Access Riser, 48" dia, 6' deep D - 54 2,000.00$Each
Pond Overflow Spillway D - 55 16.00$SY
Restrictor/Oil Separator, 12"D - 56 1,150.00$Each
Restrictor/Oil Separator, 15"D - 57 1,350.00$Each
Restrictor/Oil Separator, 18"D - 58 1,700.00$Each
Riprap, placed D - 59 42.00$CY
Tank End Reducer (36" diameter)D - 60 1,200.00$Each
Trash Rack, 12"D - 61 350.00$Each
Trash Rack, 15"D - 62 410.00$Each
Trash Rack, 18"D - 63 480.00$Each
Trash Rack, 21"D - 64 550.00$Each
Page 7 of 9 SUBTOTAL
& Drainage Facilities
*KCC 27A authorizes only one bond reduction.
bondquantityworksheet.xls
Unit prices updated: 03/02/2015
Version: 03/02/2015
Report Date: 2/15/2016
Site Improvement Bond Quantity Worksheet Web date: 04/03/2015
Existing Future Public Private
Right-of-way Right of Way Improvements
Unit Price Unit Quant.Price Quant.Cost Quant.Cost
PARKING LOT SURFACING
No.
2" AC, 2" top course rock & 4" borrow PL - 1 21.00$SY NA NA
2" AC, 1.5" top course & 2.5" base coursePL - 2 28.00$SY NA NA
4" select borrow PL - 3 5.00$SY NA NA
1.5" top course rock & 2.5" base course PL - 4 14.00$SY NA NA
UTILITY POLES & STREET LIGHTING Utility pole relocation costs must be accompanied by Franchise Utility's Cost Estimate
Utility Pole(s) Relocation UP-1
Street Light Poles w/Luminaires UP-2 Each
WRITE-IN-ITEMS
(Such as detention/water quality vaults.)No.
WI - 1 Each
WI - 2 SY
WI - 3 CY
WI - 4 LF
WI - 5 FT
WI - 6
WI - 7
WI - 8
WI - 9
WI - 10
SUBTOTAL
SUBTOTAL (SUM ALL PAGES):3,020.00 8,870.00
30% CONTINGENCY & MOBILIZATION:906.00 2,661.00
GRANDTOTAL:3,926.00 11,531.00
COLUMN:B C D
Page 8 of 9
& Drainage Facilities
Not To Be Used For Roads Or Shoulders
Lump Sum
*KCC 27A authorizes only one bond reduction.
bondquantityworksheet.xls
Unit prices updated: 03/02/2015
Version: 03/02/2015
Report Date: 2/15/2016
Site Improvement Bond Quantity Worksheet Web date: 04/03/2015
Original bond computations prepared by:
Name:Date:
PE Registration Number:Tel. #:
Firm Name:
Address:Project No:
Stabilization/Erosion Sediment Control (ESC)(A)
Existing Right-of-Way Improvements (B)
Future Public Right of Way & Drainage Facilities (C)
Private Improvements (D)
Calculated Quantity Completed
Total Right-of Way and/or Site Restoration Bond*/**(A+B)
(First $7,500 of bond* shall be cash.)
Performance Bond* Amount (A+B+C+D) = TOTAL (T)T x 0.30
Minimum is $2000.Minimum is $2000.
Maintenance/Defect Bond* Total
Minimum is $2000.
NAME OF PERSON PREPARING BOND* REDUCTION:Date:
* NOTE:The word "bond" as used in this document means a financial guarantee acceptable to King County.
** NOTE:KCC 27A authorizes right of way and site restoration bonds to be combined when both are required.
The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition, corrective work, both on- and off-site needs to be included.
Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged, some estimated costs for restoration
needs to be reflected in this amount. The 30% contingency and mobilization costs are computed in this quantity.
*** NOTE:Per KCC 27A, total bond amounts remaining after reduction shall not be less than 30% of the original amount (T) or as revised by major design changes.
REQUIRED BOND* AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY KING COUNTY
(B+C) x
0.25 =
6,467.5$
11,531.0$
21,924.5$
2/15/2016
981.5$
Laura Bartenhagen, P.E.
6,467.5$
-$
3,926.0$
6,577.4$
2/15/2016
(253) 838-6113
FINANCIAL GUARANTEE REQUIREMENTS
PUBLIC ROAD & DRAINAGE
MAINTENANCE/DEFECT BOND*
Laura Bartenhagen, P.E.
ESM Consulting Engineers, LLC
33400 8th Avenue South, Suite 205, Federal Way, WA 98003
PERFORMANCE BOND*
AMOUNT
40111
MINIMUM BOND* AMOUNT
REQUIRED FOR RECORDING OR
TEMPORARY OCCUPANCY AT
SUBSTANTIAL COMPLETION ***
Page 9 of 9
bondquantityworksheet.xls
Check out the DDES Web site at www.kingcounty.gov/permits
Unit prices updated: 03/02/2015
Version: 03/02/2015
Report Date: 2/15/2016
10-1
10.OPERATIONS AND MAINTENANCE MANUAL
The Operations and Maintenance Manual is provided in Appendix D.
APPENDIX A
KCRTS Pond Sizing Output, Kristar Perk Filter Sizing Sheets and Conveyance Output
(Excerpt from Originally Approved Project TIR)
Updated KCRTS Pond Sizing Output
Innovative stormwater management products
Advantages and Features
Superior Flow Rates
• High efficiency in compact footprint
• Lower media replacement costs
• Optimizes design flexibility
Field Validated
• High TSS removal
• Enhanced phosphorous removal rate
• In-line installation eliminates
the need for separate junction structures
Washington State Department of Ecology
• GULD for basic and enhanced phosphorous treatment
• Allowed for in-line installation
VAULT STYLE CONFIGURATION
POD SYSTEM CONFIGURATION
STEEL PERK FILTER
DISTRIBUTED BY:
KriStar Enterprises, Inc. • 360 Sutton Place • Santa Rosa, CA 95407
PH: 800-579-8819 • FAX: 707-524-8186 • www.kristar.com
©2010 KriStar Enterprises, Inc.
Innovative stormwater management products
Applications
FloGard® PERK FILTER systems are available in
vault, manhole, and catch basin configurations.
Typical installation locations include:
• New drop inlets or vaults in commercial,
residential, or industrial developments
• Pretreatment for retention/detention systems
• Variety of system configurations available
A shallow concrete vault configuration.
Stackable Cartridge Design*
Cartridge Height Treatment Flow Rate (inches) (WA DOE) (Standard)
12 6.8 12
18 10.2 18
24 13.6 24
30 17 30
* Standard cartridge heights are 12 & 18 inches.
Stack as necessary to meet flow rate capacity.
A close-up view of a single cartridge FloGard®
PERK FILTER concrete catch basin installation.
Materials
All PERK FILTER Catch Basin systems are
fabricated from durable precast concrete.
PERK FILTER Catch Basins are also available
in steel.
Maintenance
• Easy access to pretreatment chamber for
removal of debris and sediment
• Cartridge construction allows for easy
handling when changing filter media
PERK FILTER CARTRIDGEMANHOLE STYLE CONFIGURATION
FloGard® Perk Filter
Cartridge Sizing Determination WA
Downstream of Detention v1.01
Date 12/29/2014
Site Information
Project Name Greenleaf
Project Location Renton, WA
Drainage Area 7.44 ac
Impervious Area 3.62 ac
% Impervious 49%
Runoff Coefficient 0.49
Flow-Based Calculations (not used when downstream of detention)
On-Line WQ Flow Rate (from WWHM)0.202 cfs
90.7 gpm
Cartridge Stack Height 24 in
Allowed Loading Rate (1.5 or 2.5)1.5 gpm/sf
Allowed Cartridge Flow Capacity 13.6 gpm
Number of Cartridge Stacks Required 7
Downstream of Detention
Peak Release Rate (Qp)7.91 cfs
Treatment Release Rate (Qt)0.202 cfs
Detention Pretreatment Credit 50%
Mass Loading Calculations
Mean Annual Rainfall (P)39 in
Required % Removal 80%
Required % Runoff Capture 91%
Mean Annual Runoff (Vt)467,648 cf
Assumed Pollutant EMC 70 mg/L
Annual Mass Load 2038.95 lb
Filter System
Unit Type Perk Filter
Cartridge Stack Height 24 in
Design Loading Rate 1.5 gpm/sf
Cartridge Quantity Based on Mass Loading
Mass Removed by Pretreatment 1019.48 lb
Mass Load to Filter after Pretreatment 1019.48 lb
Required Filter Efficiency 0.80
Mass Removal Required 815.58 lb
Allowed Cartridge Flow Capacity 13.6 gpm
Mass Load per Cartridge 76 lb
Number of Cartridge Stacks Required 11
Treatment Flow Capacity 0.33 cfs
Determine Limiting Sizing Approach
# of Cartridge Stacks based on Flow 7
Method to Use (Flow-Based, Mass Load)Mass Loading
Summary
Treatment Flow Rate Provided 0.33 cfs
Cartridge Stack Flow Capacity 13.6 gpm
Cartridge Stack Height 24 in
Number of Cartridge Stacks 11
On Site Conveyance System
25-Year Storm Event
100-Year Storm Event
ROUTEHYD [] THRU [Onsite] USING [25 yr] AND [Seattle] NOTZERO RELATIVE RATIONAL
Rational Method analysis
Reach ID Area (ac) TC (min) i (in/hr) Flow (cfs)Full Q
(cfs)Full ratio nDepth
(ft)Size nVel (ft/s) fVel (ft/s) CArea
P-018 0.08 6.3 2.5549 0.1673 3.6488 0.0459 0.1457
12 in
Diam 2.3631 4.6457 B-018
P-019 0.16 6.4693 2.5187 0.3299 10.8975 0.0303 0.1196 12 in 6.2102 13.8751 B-019
P-013 0.81 6.3 2.5549 1.3809 3.7271 0.3705 0.4216 12 in 4.3892 4.7455 B-013
P-012 1.56 6.998 2.4142 2.5893 21.5617 0.1201 0.2344 12 in 18.4744 27.4532 B-012
P-015 0.34 6.3 2.5549 0.5825 3.6851 0.1581 0.2687 12 in 3.4279 4.692 B-015
P-014 0.37 6.4702 2.5185 0.6422 3.6488 0.176 0.2836 12 in 3.5044 4.6457 B-014
P-011 1.96 7.0395 2.4066 3.244 6.0837 0.5332 0.5196 12 in 7.8676 7.746 B-011
P-010 2.64 7.3615 2.3492 4.2686 10.9708 0.3891 0.6501 18 in 5.8139 6.2082 B-010
P-009 3.41 7.4331 2.337 5.319 10.7578 0.4944 0.7452 18 in 6.0692 6.0876 B-009
P-007 0.83 6.3 2.5549 0.9785 3.721 0.263 0.3499 12 in 3.9956 4.7377 B-007
P-006 1.39 6.3959 2.5342 1.9843 14.5768 0.1361 0.2492 12 in 12.9832 18.5597 B-005;B-
P-005 0.07 6.3 2.5549 0.161 8.7418 0.0184 0.0941 12 in 4.3027 11.1304 B-005
P-004 1.53 6.4768 2.5171 2.2553 12.1565 0.1855 0.2919 12 in 11.8242 15.4781 B-004
P-003 5.05 7.8231 2.2735 7.3922 32.3449 0.2285 0.4873 18 in 14.8524 18.3035 B-003
P-002 5.05 7.896 2.2621 7.3553 38.5782 0.1907 0.4439 18 in 16.8094 21.8308
P-001 6.07 8.019 2.2434 8.5954 74.252 0.1158 0.3458 18 in 27.905 42.018 B-001
HGL Analysis
From
Node To Node HG El (ft) App (ft) Bend (ft)Junct Loss
(ft)
Adjusted
HG El (ft)Max El (ft)
445
N-001 Outlet 449.7946 ------0.3288 ------450.1234 452.92
N-002 N-001 457.5081 ------0.0968 ------457.605 464.3
N-003 N-002 460.4686 ------0.0521 0.0412 460.5619 464.46
N-009 N-003 460.9042 0.5249 0.7175 ------461.0968 464.54
N-010 N-009 461.2252 0.2649 0.3662 ------461.3265 464.54
N-011 N-010 463.5279 ------0.1658 0.0313 463.725 471.6
N-012 N-011 471.3091 ------0.2774 0.0537 471.6402 475.31
N-019 N-012 479.3895 ------0.1119 ------479.5014 484.07
N-018 N-019 479.6017 ------------------479.6017 484.07
N-013 N-012 471.7143 ------------------471.7143 475.31
N-014 N-011 463.747 0.0085 0.0033 ------463.7418 472.29
N-015 N-014 463.758 ------------------463.758 468.38
N-004 N-003 463.2268 ------0.5082 0.1725 463.9074 467.27
N-006 N-004 468.1624 ------0.2038 ------468.3662 472.3
N-007 N-006 468.4038 ------------------468.4038 472.3
N-005 N-004 463.9085 ------------------463.9085 468.33
No approach losses at node N-011 because inverts and/or crowns are offset.
Conduit Notes
Reach HW
Depth (ft)
HW/D
ratio Q (cfs)TW Depth
(ft)Dc (ft)Dn (ft)
P-001 1.8746 1.2498 8.6 8.75 1.1356 0.3458
P-002 1.6181 1.0787 7.36 2.2034 1.0511 0.4439
P-003 1.6386 1.0924 7.39 1.715 1.0537 0.4873
P-009 2.0742 1.3828 5.32 1.7319 0.8889 0.7452
P-010 1.6852 1.1235 4.27 1.5568 0.7922 0.6501
P-011 1.2479 1.2479 3.24 1.1565 0.7714 0.5196
P-012 0.9991 0.9991 2.59 1.445 0.6898 0.2344
P-019 0.2995 0.2995 0.33 1.3303 0.2368 0.1196
P-018 0.3917 0.3917 0.17 0.4114 0.1673 0.1457
P-013 1.4043 1.4043 1.38 1.3302 0.4973 0.4216
P-014 1.467 1.467 0.64 1.445 0.3338 0.2836
P-015 1.1665 1.1665 0.58 1.1518 0.3172 0.2687
P-004 0.9568 0.9568 2.26 1.2319 0.6424 0.2919
P-006 0.8624 0.8624 1.98 1.6374 0.6017 0.2492
P-007 1.1034 1.1034 0.98 1.0662 0.4154 0.3499
P-005 1.6395 1.6395 0.16 1.6384 0.164 0.0941
SuperCrit flow, Inlet end controls
Outlet Control
Outlet Control
Comment
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
Outlet Control
Outlet Control
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
Outlet Control M1 Backwater
Outlet Control
Outlet Control
Outlet Control
SuperCrit flow, Inlet end controls
ROUTEHYD [] THRU [Onsite] USING [100 yr] AND [Seattle] NOTZERO RELATIVE RATIONAL
Rational Method analysis
Reach ID Area (ac) TC (min) i (in/hr) Flow (cfs)Full Q
(cfs)Full ratio nDepth
(ft)Size nVel (ft/s) fVel (ft/s) CArea
P-018 0.08 6.3 3.209 0.2102 3.6488 0.0576 0.1628
12 in
Diam 2.5261 4.6457 B-018
P-019 0.16 6.4583 3.1659 0.4147 10.8975 0.0381 0.1331 12 in 6.6774 13.8751 B-019
P-013 0.81 6.3 3.209 1.7345 3.7271 0.4654 0.4797 12 in 4.6574 4.7455 B-013
P-012 1.56 6.9501 3.0418 3.2623 21.5617 0.1513 0.2623 12 in 19.8579 27.4532 B-012
P-015 0.34 6.3 3.209 0.7316 3.6851 0.1985 0.3022 12 in 3.6547 4.692 B-015
P-014 0.37 6.4596 3.1655 0.8072 3.6488 0.2212 0.3199 12 in 3.7274 4.6457 B-014
P-011 1.96 6.9887 3.0326 4.0879 6.0837 0.6719 0.6004 12 in 8.3011 7.746 B-011
P-010 2.64 7.2938 2.9628 5.3833 10.9708 0.4907 0.7419 18 in 6.1775 6.2082 B-010
P-009 3.41 7.3613 2.9479 6.7095 10.7578 0.6237 0.858 18 in 6.4201 6.0876 B-009
P-007 0.83 6.3 3.209 1.229 3.721 0.3303 0.3932 12 in 4.2872 4.7377 B-007
P-006 1.39 6.3894 3.1844 2.4934 14.5768 0.1711 0.2793 12 in 13.9014 18.5597 B-005;B-
P-005 0.07 6.3 3.209 0.2022 8.7418 0.0231 0.1051 12 in 4.6005 11.1304 B-005
P-004 1.53 6.4649 3.1641 2.835 12.1565 0.2332 0.328 12 in 12.6467 15.4781 B-004
P-003 5.05 7.7299 2.8705 9.3333 32.3449 0.2886 0.5518 18 in 15.8255 18.3035 B-003
P-002 5.05 7.7984 2.8567 9.2886 38.5782 0.2408 0.5004 18 in 17.993 21.8308
P-001 6.07 7.9132 2.834 10.8586 74.252 0.1462 0.3867 18 in 30.1019 42.018 B-001
HGL Analysis
From
Node To Node HG El (ft) App (ft) Bend (ft)Junct Loss
(ft)
Adjusted
HG El (ft)Max El (ft)
445
N-001 Outlet 450.3826 ------0.5244 ------450.907 452.92
N-002 N-001 457.8743 ------0.1544 ------458.0286 464.3
N-003 N-002 460.802 ------0.0828 0.0654 460.9502 464.46
N-009 N-003 461.495 0.1441 0.197 ------461.5478 464.54
N-010 N-009 461.7521 0.4207 0.5816 ------461.913 464.54
N-011 N-010 463.8208 ------0.2631 0.0496 464.1335 471.6
N-012 N-011 471.676 ------0.0702 0.0136 471.7598 475.31
N-019 N-012 479.431 ------0.1279 ------479.5589 484.07
N-018 N-019 479.6748 ------------------479.6748 484.07
N-013 N-012 471.8767 ------------------471.8767 475.31
N-014 N-011 464.1684 0.0135 0.0052 ------464.1601 472.29
N-015 N-014 464.1848 ------------------464.1848 468.38
N-004 N-003 463.4169 ------0.0304 0.0103 463.4576 467.27
N-006 N-004 468.3171 ------0.0313 ------468.3484 472.3
N-007 N-006 468.4075 ------------------468.4075 472.3
N-005 N-004 463.4593 ------------------463.4593 468.33
No approach losses at node N-011 because inverts and/or crowns are offset.
Conduit Notes
Reach HW
Depth (ft)
HW/D
ratio Q (cfs)TW Depth
(ft)Dc (ft)Dn (ft)
P-001 2.4626 1.6418 10.86 8.75 1.2635 0.3867
P-002 1.9843 1.3228 9.29 2.987 1.1784 0.5004
P-003 1.972 1.3147 9.33 2.1386 1.1811 0.5518
P-009 2.665 1.7766 6.71 2.1202 1.0027 0.858
P-010 2.2121 1.4747 5.38 2.0078 0.8944 0.7419
P-011 1.5408 1.5408 4.09 1.743 0.8551 0.6004
P-012 1.366 1.366 3.26 1.8535 0.7735 0.2623
P-019 0.341 0.341 0.41 1.4499 0.2663 0.1331
P-018 0.4648 0.4648 0.21 0.4689 0.1881 0.1628
P-013 1.5667 1.5667 1.73 1.4498 0.5605 0.4797
P-014 1.8884 1.8884 0.81 1.8535 0.3758 0.3199
P-015 1.5933 1.5933 0.73 1.5701 0.357 0.3022
P-004 1.1469 1.1469 2.84 1.6202 0.7224 0.328
P-006 1.0171 1.0171 2.49 1.1876 0.6766 0.2793
P-007 1.1071 1.1071 1.23 1.0484 0.4677 0.3932
P-005 1.1903 1.1903 0.2 1.1886 0.1844 0.1051
Outlet Control
Outlet Control
Outlet Control
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
Outlet Control
Outlet Control
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
Outlet Control M1 Backwater
Comment
SuperCrit flow, Inlet end controls
SuperCrit flow, Inlet end controls
Outlet Control
Outlet Control
Layout Report: Onsite
Event Precip (in)
2 yr 24 hr 2.00
10 year 2.90
25 year 3.40
100 year 3.90
Reach Records
Record Id: P-001
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode Outlet UpNode N-001
Material unspecified Size 18 in Diam
Ent Losses Groove End w/Headwall
Length 49.00 ft Slope 23.82%
Up Invert 447.92 ft Dn Invert 436.25 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-002
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-001 UpNode N-002
Material unspecified Size 18 in Diam
Ent Losses Groove End w/Headwall
Length 124.00 ft Slope 6.43%
Up Invert 455.89 ft Dn Invert 447.92 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-003
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-002 UpNode N-003
Material unspecified Size 18 in Diam
Ent Losses Groove End w/Headwall
Length 65.00 ft Slope 4.52%
Up Invert 458.83 ft Dn Invert 455.89 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-004
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-003 UpNode N-004
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 53.00 ft Slope 5.55%
Up Invert 462.27 ft Dn Invert 459.33 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-005
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-004 UpNode N-005
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 30.00 ft Slope 2.87%
Up Invert 463.13 ft Dn Invert 462.269 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-006
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-004 UpNode N-006
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 63.00 ft Slope 7.98%
Up Invert 467.30 ft Dn Invert 462.27 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-007
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-006 UpNode N-007
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 23.00 ft Slope 0.52%
Up Invert 467.42 ft Dn Invert 467.30 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-009
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-003 UpNode N-009
Material unspecified Size 18 in Diam
Ent Losses Groove End w/Headwall
Length 142.00 ft Slope 0.50%
Up Invert 459.54 ft Dn Invert 458.83 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-010
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-009 UpNode N-010
Material unspecified Size 18 in Diam
Ent Losses Groove End w/Headwall
Length 25.00 ft Slope 0.52%
Up Invert 459.67 ft Dn Invert 459.54 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-011
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-010 UpNode N-011
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 152.00 ft Slope 1.39%
Up Invert 462.28 ft Dn Invert 460.17 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-012
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-011 UpNode N-012
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 46.00 ft Slope 17.46%
Up Invert 470.31 ft Dn Invert 462.28 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-013
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-012 UpNode N-013
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 23.00 ft Slope 0.52%
Up Invert 470.43 ft Dn Invert 470.31 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-014
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-011 UpNode N-014
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 62.00 ft Slope 0.50%
Up Invert 462.59 ft Dn Invert 462.28 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-015
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-014 UpNode N-015
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 35.00 ft Slope 0.51%
Up Invert 462.77 ft Dn Invert 462.59 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-018
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-019 UpNode N-018
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 24.00 ft Slope 0.50%
Up Invert 479.21 ft Dn Invert 479.09 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Record Id: P-019
Section Shape:Circular
Uniform Flow Method:Manning's Coefficient:0.009
Routing Method:Travel Time Shift Contributing Hyd
DnNode N-012 UpNode N-019
Material unspecified Size 12 in Diam
Ent Losses Groove End w/Headwall
Length 197.00 ft Slope 4.46%
Up Invert 479.09 ft Dn Invert 470.3099 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50%2.00%3.00 ft
Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr
Node Records
Record Id: N-001
Descrip:Prototype Record Increment 0.10 ft
Start El.447.92 ft Max El.452.92 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-002
Descrip:Prototype Record Increment 0.10 ft
Start El.455.89 ft Max El.464.30 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-003
Descrip:Prototype Record Increment 0.10 ft
Start El.458.83 ft Max El.464.46 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-004
Descrip:Prototype Record Increment 0.10 ft
Start El.462.27 ft Max El.467.27 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-005
Descrip:Prototype Record Increment 0.10 ft
Start El.463.13 ft Max El.468.33 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 1
Channelization No Special Shape
Catch 0.00 ft Bottom Area 3.97 sf
MH/CB Type Node
Record Id: N-006
Descrip:Prototype Record Increment 0.10 ft
Start El.467.30 ft Max El.472.30 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-007
Descrip:Prototype Record Increment 0.10 ft
Start El.467.42 ft Max El.472.30 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 1
Channelization No Special Shape
Catch 0.00 ft Bottom Area 3.97 sf
MH/CB Type Node
Record Id: N-009
Descrip:Prototype Record Increment 0.10 ft
Start El.459.54 ft Max El.464.54 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-010
Descrip:Prototype Record Increment 0.10 ft
Start El.459.67 ft Max El.464.54 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-011
Descrip:Prototype Record Increment 0.10 ft
Start El.462.28 ft Max El.471.60 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-012
Descrip:Prototype Record Increment 0.10 ft
Start El.470.31 ft Max El.475.31 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 1
Channelization No Special Shape
Catch 0.00 ft Bottom Area 3.97 sf
MH/CB Type Node
Record Id: N-013
Descrip:Prototype Record Increment 0.10 ft
Start El.470.43 ft Max El.475.31 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 1
Channelization No Special Shape
Catch 0.00 ft Bottom Area 3.97 sf
MH/CB Type Node
Record Id: N-014
Descrip:Prototype Record Increment 0.10 ft
Start El.462.59 ft Max El.472.29 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 2-48
Channelization No Special Shape
Catch 0.00 ft Bottom Area 12.5664 sf
MH/CB Type Node
Record Id: N-015
Descrip:Prototype Record Increment 0.10 ft
Start El.462.77 ft Max El.468.38 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 1
Channelization No Special Shape
Catch 0.00 ft Bottom Area 3.97 sf
MH/CB Type Node
Record Id: N-018
Descrip:Prototype Record Increment 0.10 ft
Start El.479.21 ft Max El.484.07 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 1
Channelization No Special Shape
Catch 0.00 ft Bottom Area 3.97 sf
MH/CB Type Node
Record Id: N-019
Descrip:Prototype Record Increment 0.10 ft
Start El.479.09 ft Max El.484.07 ft
Void Ratio 100.00
Condition Proposed Structure Type CB-TYPE 1
Channelization No Special Shape
Catch 0.00 ft Bottom Area 3.97 sf
MH/CB Type Node
Record Id: Outlet
Descrip:Prototype Record Increment 0.10 ft
Start El. 436.25 ft Max El.445.00
ft
Void Ratio 100.00
Dummy Type Node
Contributing Drainage Areas
Record Id: B-001
Design Method Rational IDF Table:SeattleRecord Id: B-003
Design Method Rational IDF Table:SeattleRecord Id: B-004
Design Method Rational IDF Table:SeattleRecord Id: B-005
Design Method Rational IDF Table:SeattleRecord Id: B-006
Design Method Rational IDF Table:SeattleRecord Id: B-007
Design Method Rational IDF Table:SeattleRecord Id: B-009
Design Method Rational IDF Table:SeattleRecord Id: B-010
Design Method Rational IDF Table:SeattleRecord Id: B-011
Design Method Rational IDF Table:SeattleRecord Id: B-012
Design Method Rational IDF Table:SeattleRecord Id: B-013
Design Method Rational IDF Table:SeattleRecord Id: B-014
Design Method Rational IDF Table:SeattleRecord Id: B-015
Design Method Rational IDF Table:SeattleRecord Id: B-018
Design Method Rational IDF Table:SeattleRecord Id: B-019
Design Method Rational IDF Table:SeattleRecord Id: B-POND
Pre-Developed Land Use Condition
Greenleaf Pond KCRTS Output
8.57 0.00 0.000000 Till Forest 0.00 0.00 0.000000 Till Pasture 0.00 0.00 0.000000 Till Grass 0.00 0.00 0.000000 Outwash Forest 0.00 0.00 0.000000 Outwash Pasture 0.00 0.00 0.000000 Outwash Grass 0.00 0.00 0.000000 Wetland 0.00 0.00 0.000000 Impervious predev.tsf ST 1.00000
Flow Frequency Analysis LogPearson III Coefficients Time Series File:predev.tsf Mean= -0.684 StdDev= 0.233 Project Location:Sea-Tac Skew= -0.143 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.254 16 2/16/49 22:00 0.576 1 89.50 0.989
0.496 5 3/03/50 16:00 0.544 2 32.13 0.969 0.544 2 2/09/51 18:00 0.516 3 19.58 0.949 0.171 32 1/30/52 9:00 0.505 4 14.08 0.929 0.132 42 1/18/53 19:00 0.496 5 10.99 0.909 0.192 28 1/06/54 5:00 0.419 6 9.01 0.889 0.338 9 2/07/55 21:00 0.404 7 7.64 0.869 0.288 13 12/20/55 17:00 0.364 8 6.63 0.849 0.224 21 12/09/56 15:00 0.338 9 5.86 0.829 0.238 20 1/16/58 20:00 0.338 10 5.24 0.809
0.196 24 1/24/59 2:00 0.335 11 4.75 0.789
0.364 8 11/20/59 21:00 0.292 12 4.34 0.769 0.197 23 2/24/61 15:00 0.288 13 3.99 0.749 0.118 44 1/03/62 2:00 0.282 14 3.70 0.729 0.157 36 11/25/62 15:00 0.262 15 3.44 0.709 0.195 25 1/01/64 18:00 0.254 16 3.22 0.690 0.138 40 11/30/64 12:00 0.251 17 3.03 0.670 0.150 38 1/06/66 3:00 0.251 18 2.85 0.650 0.335 11 1/19/67 14:00 0.244 19 2.70 0.630 0.198 22 2/03/68 23:00 0.238 20 2.56 0.610 0.194 27 12/03/68 17:00 0.224 21 2.44 0.590 0.164 34 1/13/70 23:00 0.198 22 2.32 0.570 0.133 41 12/06/70 8:00 0.197 23 2.22 0.550 0.404 7 2/28/72 3:00 0.196 24 2.13 0.530 0.179 30 1/13/73 5:00 0.195 25 2.04 0.510 0.194 26 1/15/74 2:00 0.194 26 1.96 0.490 0.292 12 12/26/74 23:00 0.194 27 1.89 0.470 0.180 29 12/03/75 17:00 0.192 28 1.82 0.450 0.020 50 3/24/77 20:00 0.180 29 1.75 0.430 0.156 37 12/10/77 17:00 0.179 30 1.70 0.410
0.094 46 2/12/79 8:00 0.175 31 1.64 0.390 0.251 18 12/15/79 8:00 0.171 32 1.59 0.370
0.139 39 12/26/80 4:00 0.168 33 1.54 0.350
0.251 17 10/06/81 15:00 0.164 34 1.49 0.330 0.244 19 1/05/83 8:00 0.162 35 1.45 0.310 0.162 35 1/24/84 11:00 0.157 36 1.41 0.291 0.078 48 2/11/85 6:00 0.156 37 1.37 0.271 0.419 6 1/18/86 21:00 0.150 38 1.33 0.251 0.338 10 11/24/86 4:00 0.139 39 1.30 0.231 0.128 43 1/14/88 12:00 0.138 40 1.27 0.211 0.081 47 4/05/89 16:00 0.133 41 1.24 0.191 0.576 1 1/09/90 9:00 0.132 42 1.21 0.171 0.505 4 4/05/91 2:00 0.128 43 1.18 0.151
0.168 33 1/27/92 17:00 0.118 44 1.15 0.131 0.175 31 3/23/93 0:00 0.098 45 1.12 0.111 0.048 49 3/03/94 4:00 0.094 46 1.10 0.091 0.262 15 2/19/95 20:00 0.081 47 1.08 0.071 0.516 3 2/09/96 1:00 0.078 48 1.05 0.051 0.282 14 1/02/97 9:00 0.048 49 1.03 0.031 0.098 45 1/07/98 10:00 0.020 50 1.01 0.011 Computed Peaks 0.682 100.00 0.990 Computed Peaks 0.598 50.00 0.980
Computed Peaks 0.516 25.00 0.960
Computed Peaks 0.408 10.00 0.900 Computed Peaks 0.386 8.00 0.875 Computed Peaks 0.326 5.00 0.800 Computed Peaks 0.210 2.00 0.500 Computed Peaks 0.139 1.30 0.231
Developed Land Use Condition
0.00 0.00 0.000000 Till Forest 0.00 0.00 0.000000 Till Pasture 4.46 0.00 0.000000 Till Grass 0.00 0.00 0.000000 Outwash Forest 0.00 0.00 0.000000 Outwash Pasture 0.00 0.00 0.000000 Outwash Grass
0.00 0.00 0.000000 Wetland 3.51 0.00 0.000000 Impervious dev.tsf ST 1.00000 Flow Frequency Analysis LogPearson III Coefficients Time Series File:dev.tsf Mean= 0.069 StdDev= 0.123 Project Location:Sea-Tac Skew= 0.397
---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 1.23 20 2/16/49 21:00 2.33 1 89.50 0.989 2.26 2 3/03/50 16:00 2.26 2 32.13 0.969 1.31 19 2/09/51 2:00 2.09 3 19.58 0.949 0.900 43 10/15/51 13:00 1.94 4 14.08 0.929 0.902 42 3/24/53 15:00 1.64 5 10.99 0.909 1.13 26 12/19/53 19:00 1.63 6 9.01 0.889
1.14 24 11/25/54 2:00 1.58 7 7.64 0.869
1.14 25 12/20/55 17:00 1.55 8 6.63 0.849 1.38 13 12/09/56 14:00 1.51 9 5.86 0.829 1.18 21 12/25/57 16:00 1.49 10 5.24 0.809 0.859 46 11/18/58 13:00 1.42 11 4.75 0.789 1.15 23 11/20/59 5:00 1.40 12 4.34 0.769 1.02 34 2/14/61 21:00 1.38 13 3.99 0.749 0.964 39 11/22/61 2:00 1.38 14 3.70 0.729 1.02 31 12/15/62 2:00 1.37 15 3.44 0.709 1.12 28 12/31/63 23:00 1.35 16 3.22 0.690 0.991 38 12/21/64 4:00 1.33 17 3.03 0.670
1.01 35 1/05/66 16:00 1.31 18 2.85 0.650 1.55 8 11/13/66 19:00 1.31 19 2.70 0.630 1.64 5 8/24/68 16:00 1.23 20 2.56 0.610 0.930 41 12/03/68 16:00 1.18 21 2.44 0.590 1.02 32 1/13/70 22:00 1.18 22 2.32 0.570 0.994 37 12/06/70 8:00 1.15 23 2.22 0.550 1.63 6 2/27/72 7:00 1.14 24 2.13 0.530 0.889 44 1/13/73 2:00 1.14 25 2.04 0.510 1.12 27 11/28/73 9:00 1.13 26 1.96 0.490
1.51 9 12/26/74 23:00 1.12 27 1.89 0.470
0.935 40 12/02/75 20:00 1.12 28 1.82 0.450 1.00 36 8/26/77 2:00 1.09 29 1.75 0.430 1.42 11 9/22/78 19:00 1.06 30 1.70 0.410 1.18 22 9/08/79 15:00 1.02 31 1.64 0.390 1.35 16 12/14/79 21:00 1.02 32 1.59 0.370 1.37 15 11/21/80 11:00 1.02 33 1.54 0.350 1.94 4 10/06/81 0:00 1.02 34 1.49 0.330 1.31 18 10/28/82 16:00 1.01 35 1.45 0.310
1.09 29 1/03/84 1:00 1.00 36 1.41 0.291
0.882 45 6/06/85 22:00 0.994 37 1.37 0.271 1.38 14 1/18/86 16:00 0.991 38 1.33 0.251 1.58 7 10/26/86 0:00 0.964 39 1.30 0.231 0.685 49 1/14/88 0:00 0.935 40 1.27 0.211 0.841 47 8/21/89 17:00 0.930 41 1.24 0.191 2.33 1 1/09/90 6:00 0.902 42 1.21 0.171 2.09 3 11/24/90 8:00 0.900 43 1.18 0.151 1.06 30 1/27/92 15:00 0.889 44 1.15 0.131 0.638 50 12/10/92 6:00 0.882 45 1.12 0.111 0.738 48 11/30/93 22:00 0.859 46 1.10 0.091 1.02 33 11/30/94 4:00 0.841 47 1.08 0.071 1.49 10 2/08/96 10:00 0.738 48 1.05 0.051 1.33 17 1/02/97 6:00 0.685 49 1.03 0.031 1.40 12 10/04/97 15:00 0.638 50 1.01 0.011 Computed Peaks 2.45 100.00 0.990 Computed Peaks 2.22 50.00 0.980 Computed Peaks 1.99 25.00 0.960 Computed Peaks 1.70 10.00 0.900 Computed Peaks 1.64 8.00 0.875
Computed Peaks 1.48 5.00 0.800 Computed Peaks 1.15 2.00 0.500 Computed Peaks 0.942 1.30 0.231
15 Minute Flow Frequency Analysis
Flow Frequency Analysis LogPearson III Coefficients Time Series File:dev15.tsf Mean= 0.336 StdDev= 0.176 Project Location:Sea-Tac Skew= 1.436 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS) Period 3.16 9 2/16/49 17:45 9.54 1 89.50 0.989 4.39 5 3/03/50 15:00 5.50 2 32.13 0.969 1.67 37 10/08/50 4:15 4.79 3 19.58 0.949 2.07 25 10/17/51 7:15 4.50 4 14.08 0.929 1.44 45 9/30/53 3:00 4.39 5 10.99 0.909 1.72 34 12/19/53 17:30 3.37 6 9.01 0.889 1.40 46 11/25/54 1:00 3.29 7 7.64 0.869 2.02 29 10/04/55 10:00 3.28 8 6.63 0.849
2.20 18 12/09/56 12:45 3.16 9 5.86 0.829 1.96 31 1/16/58 10:00 2.59 10 5.24 0.809 2.38 14 10/18/58 19:45 2.51 11 4.75 0.789 2.51 11 10/10/59 22:00 2.48 12 4.34 0.769 2.14 22 2/14/61 20:15 2.42 13 3.99 0.749 1.62 40 8/04/62 13:15 2.38 14 3.70 0.729 1.70 36 12/01/62 20:15 2.31 15 3.44 0.709 1.25 49 6/05/64 15:00 2.28 16 3.22 0.690 2.05 26 4/20/65 19:30 2.21 17 3.03 0.670 1.31 48 1/05/66 15:00 2.20 18 2.85 0.650
2.31 15 11/13/66 17:45 2.18 19 2.70 0.630 4.79 3 8/24/68 15:00 2.15 20 2.56 0.610 2.03 28 10/20/68 12:00 2.15 21 2.44 0.590 1.21 50 1/13/70 20:45 2.14 22 2.32 0.570 1.47 43 12/06/70 7:00 2.09 23 2.22 0.550 3.28 8 12/08/71 17:15 2.09 24 2.13 0.530 1.66 38 4/18/73 9:30 2.07 25 2.04 0.510 2.15 21 11/28/73 8:00 2.05 26 1.96 0.490 2.09 23 8/17/75 23:00 2.04 27 1.89 0.470
1.56 42 10/29/75 7:00 2.03 28 1.82 0.450 1.32 47 8/26/77 1:00 2.02 29 1.75 0.430 2.42 13 9/17/78 1:00 1.98 30 1.70 0.410 3.29 7 9/08/79 13:45 1.96 31 1.64 0.390 2.59 10 12/14/79 20:00 1.93 32 1.59 0.370 2.18 19 9/21/81 8:00 1.79 33 1.54 0.350 5.50 2 10/05/81 22:15 1.72 34 1.49 0.330 2.09 24 10/28/82 16:00 1.71 35 1.45 0.310 1.65 39 1/02/84 23:45 1.70 36 1.41 0.291
1.46 44 6/06/85 21:15 1.67 37 1.37 0.271 2.21 17 10/27/85 10:45 1.66 38 1.33 0.251 2.48 12 10/25/86 22:45 1.65 39 1.30 0.231 1.93 32 5/13/88 17:30 1.62 40 1.27 0.211 1.79 33 8/21/89 16:00 1.61 41 1.24 0.191 3.37 6 1/09/90 5:30 1.56 42 1.21 0.171 2.15 20 4/03/91 20:15 1.47 43 1.18 0.151 1.61 41 1/27/92 15:00 1.46 44 1.15 0.131 1.98 30 6/09/93 12:15 1.44 45 1.12 0.111
1.71 35 11/17/93 16:45 1.40 46 1.10 0.091
2.04 27 6/05/95 17:00 1.32 47 1.08 0.071 2.28 16 5/19/96 11:30 1.31 48 1.05 0.051 9.54 1 12/29/96 11:45 1.25 49 1.03 0.031 4.50 4 10/04/97 14:15 1.21 50 1.01 0.011 Computed Peaks 8.24 100.00 0.990 Computed Peaks 6.53 50.00 0.980 Computed Peaks 5.15 25.00 0.960 Computed Peaks 3.73 10.00 0.900 Computed Peaks 3.49 8.00 0.875 Computed Peaks 2.88 5.00 0.800
Computed Peaks 1.97 2.00 0.500 Computed Peaks 1.59 1.30 0.231
Offsite Land Use Condition
0.00 0.00 0.000000 Till Forest
0.00 0.00 0.000000 Till Pasture 0.74 0.00 0.000000 Till Grass 0.00 0.00 0.000000 Outwash Forest 0.00 0.00 0.000000 Outwash Pasture 0.00 0.00 0.000000 Outwash Grass 0.00 0.00 0.000000 Wetland 0.17 0.00 0.000000 Impervious offsite.tsf ST 1.00000
Flow Frequency Analysis LogPearson III Coefficients Time Series File:offsite.tsf Mean= -1.045 StdDev= 0.156 Project Location:Sea-Tac Skew= 0.454 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.098 19 2/16/49 21:00 0.220 1 89.50 0.989 0.220 1 3/03/50 16:00 0.216 2 32.13 0.969
0.115 11 2/09/51 2:00 0.187 3 19.58 0.949 0.068 39 1/30/52 8:00 0.166 4 14.08 0.929 0.065 44 3/24/53 15:00 0.147 5 10.99 0.909 0.088 26 12/19/53 19:00 0.135 6 9.01 0.889 0.093 21 2/07/55 17:00 0.130 7 7.64 0.869 0.097 20 12/20/55 17:00 0.119 8 6.63 0.849 0.114 12 12/09/56 14:00 0.119 9 5.86 0.829 0.089 24 12/25/57 16:00 0.117 10 5.24 0.809 0.066 42 1/26/59 20:00 0.115 11 4.75 0.789
0.092 22 11/20/59 5:00 0.114 12 4.34 0.769 0.079 32 2/14/61 21:00 0.111 13 3.99 0.749 0.068 40 11/22/61 2:00 0.111 14 3.70 0.729 0.082 29 12/15/62 2:00 0.111 15 3.44 0.709 0.084 28 12/31/63 23:00 0.109 16 3.22 0.690 0.072 37 12/21/64 4:00 0.103 17 3.03 0.670 0.077 34 1/05/66 16:00 0.103 18 2.85 0.650 0.119 8 11/13/66 19:00 0.098 19 2.70 0.630 0.117 10 8/24/68 16:00 0.097 20 2.56 0.610
0.072 38 12/03/68 16:00 0.093 21 2.44 0.590
0.079 33 1/13/70 22:00 0.092 22 2.32 0.570 0.080 31 12/06/70 8:00 0.092 23 2.22 0.550 0.147 5 2/27/72 7:00 0.089 24 2.13 0.530 0.066 43 1/13/73 2:00 0.089 25 2.04 0.510 0.092 23 11/28/73 9:00 0.088 26 1.96 0.490 0.130 7 12/26/74 23:00 0.087 27 1.89 0.470 0.074 35 12/02/75 20:00 0.084 28 1.82 0.450 0.061 45 8/26/77 2:00 0.082 29 1.75 0.430 0.103 17 9/22/78 19:00 0.080 30 1.70 0.410 0.066 41 9/08/79 15:00 0.080 31 1.64 0.390
0.111 15 12/14/79 21:00 0.079 32 1.59 0.370 0.103 18 11/21/80 11:00 0.079 33 1.54 0.350 0.166 4 10/06/81 15:00 0.077 34 1.49 0.330 0.089 25 10/28/82 16:00 0.074 35 1.45 0.310 0.087 27 3/15/84 20:00 0.073 36 1.41 0.291 0.057 46 6/06/85 22:00 0.072 37 1.37 0.271 0.119 9 1/18/86 16:00 0.072 38 1.33 0.251 0.109 16 11/24/86 3:00 0.068 39 1.30 0.231 0.049 48 1/14/88 12:00 0.068 40 1.27 0.211
0.055 47 11/05/88 14:00 0.066 41 1.24 0.191
0.216 2 1/09/90 6:00 0.066 42 1.21 0.171 0.187 3 11/24/90 8:00 0.066 43 1.18 0.151 0.080 30 1/27/92 15:00 0.065 44 1.15 0.131 0.048 49 3/22/93 22:00 0.061 45 1.12 0.111 0.044 50 11/30/93 22:00 0.057 46 1.10 0.091 0.073 36 11/30/94 4:00 0.055 47 1.08 0.071 0.135 6 2/08/96 10:00 0.049 48 1.05 0.051 0.111 13 1/02/97 6:00 0.048 49 1.03 0.031
0.111 14 10/04/97 15:00 0.044 50 1.01 0.011
Computed Peaks 0.234 100.00 0.990 Computed Peaks 0.205 50.00 0.980 Computed Peaks 0.178 25.00 0.960 Computed Peaks 0.145 10.00 0.900 Computed Peaks 0.138 8.00 0.875 Computed Peaks 0.121 5.00 0.800 Computed Peaks 0.088 2.00 0.500 Computed Peaks 0.068 1.30 0.231
Bypass Land Use Condition (for flow rate purposes)
0.00 0.00 0.000000 Till Forest 0.00 0.00 0.000000 Till Pasture 0.08 0.00 0.000000 Till Grass 0.00 0.00 0.000000 Outwash Forest 0.00 0.00 0.000000 Outwash Pasture 0.00 0.00 0.000000 Outwash Grass 0.00 0.00 0.000000 Wetland 0.52 0.00 0.000000 Impervious bypass.tsf ST 1.00000
Flow Frequency Analysis LogPearson III Coefficients
Time Series File:bypass.tsf Mean= -0.860 StdDev= 0.099 Project Location:Sea-Tac Skew= 0.512 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.139 20 2/16/49 21:00 0.230 1 89.50 0.989 0.210 4 3/03/50 16:00 0.223 2 32.13 0.969 0.137 23 2/09/51 2:00 0.214 3 19.58 0.949 0.119 38 10/15/51 13:00 0.210 4 14.08 0.929
0.110 43 3/24/53 15:00 0.205 5 10.99 0.909 0.131 28 12/19/53 19:00 0.200 6 9.01 0.889 0.138 22 11/25/54 2:00 0.184 7 7.64 0.869 0.134 24 11/18/55 15:00 0.180 8 6.63 0.849 0.153 15 12/09/56 14:00 0.167 9 5.86 0.829 0.139 21 12/25/57 16:00 0.165 10 5.24 0.809 0.105 47 11/18/58 13:00 0.164 11 4.75 0.789 0.131 27 11/20/59 5:00 0.163 12 4.34 0.769 0.117 39 2/14/61 21:00 0.160 13 3.99 0.749
0.119 36 11/22/61 2:00 0.160 14 3.70 0.729
0.116 41 12/15/62 2:00 0.153 15 3.44 0.709 0.133 26 12/31/63 23:00 0.150 16 3.22 0.690 0.120 34 12/21/64 4:00 0.150 17 3.03 0.670 0.119 37 1/05/66 16:00 0.146 18 2.85 0.650 0.180 8 11/13/66 19:00 0.144 19 2.70 0.630 0.200 6 8/24/68 16:00 0.139 20 2.56 0.610 0.108 44 12/03/68 16:00 0.139 21 2.44 0.590 0.120 35 1/13/70 22:00 0.138 22 2.32 0.570
0.116 40 12/05/70 9:00 0.137 23 2.22 0.550
0.167 9 12/08/71 18:00 0.134 24 2.13 0.530 0.107 45 1/13/73 2:00 0.134 25 2.04 0.510 0.124 31 11/28/73 9:00 0.133 26 1.96 0.490 0.160 13 12/26/74 23:00 0.131 27 1.89 0.470 0.107 46 12/02/75 20:00 0.131 28 1.82 0.450 0.134 25 8/26/77 2:00 0.126 29 1.75 0.430 0.184 7 9/17/78 2:00 0.126 30 1.70 0.410 0.164 11 9/08/79 15:00 0.124 31 1.64 0.390 0.150 16 12/14/79 21:00 0.124 32 1.59 0.370 0.163 12 11/21/80 11:00 0.124 33 1.54 0.350 0.223 2 10/06/81 0:00 0.120 34 1.49 0.330 0.165 10 10/28/82 16:00 0.120 35 1.45 0.310 0.126 29 1/03/84 1:00 0.119 36 1.41 0.291 0.114 42 6/06/85 22:00 0.119 37 1.37 0.271 0.146 18 1/18/86 16:00 0.119 38 1.33 0.251 0.205 5 10/26/86 0:00 0.117 39 1.30 0.231 0.096 49 11/11/87 0:00 0.116 40 1.27 0.211 0.124 32 8/21/89 17:00 0.116 41 1.24 0.191 0.230 1 1/09/90 6:00 0.114 42 1.21 0.171
0.214 3 11/24/90 8:00 0.110 43 1.18 0.151 0.124 33 1/27/92 15:00 0.108 44 1.15 0.131 0.088 50 11/01/92 16:00 0.107 45 1.12 0.111 0.100 48 11/30/93 22:00 0.107 46 1.10 0.091 0.126 30 11/30/94 4:00 0.105 47 1.08 0.071
0.150 17 2/08/96 10:00 0.100 48 1.05 0.051
0.144 19 1/02/97 6:00 0.096 49 1.03 0.031 0.160 14 10/04/97 15:00 0.088 50 1.01 0.011 Computed Peaks 0.255 100.00 0.990 Computed Peaks 0.234 50.00 0.980 Computed Peaks 0.214 25.00 0.960 Computed Peaks 0.187 10.00 0.900 Computed Peaks 0.181 8.00 0.875 Computed Peaks 0.166 5.00 0.800 Computed Peaks 0.136 2.00 0.500 Computed Peaks 0.116 1.30 0.231
As stated in the TIR, the pre-developed and developed flows have been combined with the offsite
flow (which is flow-through, no detention requirements).
PreDevCombined Flow Frequency Analysis
PreDev.tsf + offsite.tsf = PreDevCombined.tsf
Flow Frequency Analysis LogPearson III Coefficients Time Series File:predevcombined.tsf Mean= -0.571 StdDev= 0.232 Project Location:Sea-Tac Skew= -0.273 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.338 16 2/16/49 22:00 0.737 1 89.50 0.989
0.716 2 3/03/50 16:00 0.716 2 32.13 0.969
0.633 3 2/09/51 18:00 0.633 3 19.58 0.949 0.230 32 1/30/52 8:00 0.621 4 14.08 0.929 0.174 43 1/18/53 19:00 0.616 5 10.99 0.909 0.236 30 1/22/54 20:00 0.535 6 9.01 0.889 0.403 13 2/07/55 21:00 0.504 7 7.64 0.869 0.385 14 12/20/55 17:00 0.456 8 6.63 0.849 0.327 17 12/09/56 14:00 0.440 9 5.86 0.829 0.287 21 1/16/58 17:00 0.439 10 5.24 0.809
0.236 29 1/24/59 1:00 0.421 11 4.75 0.789
0.456 8 11/20/59 21:00 0.417 12 4.34 0.769 0.233 31 2/24/61 15:00 0.403 13 3.99 0.749 0.154 45 1/02/62 22:00 0.385 14 3.70 0.729 0.220 35 12/15/62 2:00 0.376 15 3.44 0.709 0.252 25 1/01/64 14:00 0.338 16 3.22 0.690 0.179 41 11/30/64 7:00 0.327 17 3.03 0.670 0.220 36 1/05/66 16:00 0.314 18 2.85 0.650 0.440 9 1/19/67 14:00 0.311 19 2.70 0.630 0.260 22 2/03/68 22:00 0.306 20 2.56 0.610 0.256 23 12/03/68 17:00 0.287 21 2.44 0.590
0.238 28 1/13/70 23:00 0.260 22 2.32 0.570 0.213 39 12/06/70 8:00 0.256 23 2.22 0.550 0.535 6 2/28/72 3:00 0.253 24 2.13 0.530 0.228 33 1/13/73 5:00 0.252 25 2.04 0.510 0.252 26 1/15/74 2:00 0.252 26 1.96 0.490
0.421 11 12/26/74 23:00 0.239 27 1.89 0.470
0.253 24 12/02/75 20:00 0.238 28 1.82 0.450 0.070 50 3/24/77 19:00 0.236 29 1.75 0.430 0.225 34 12/10/77 17:00 0.236 30 1.70 0.410 0.123 46 2/12/79 7:00 0.233 31 1.64 0.390 0.306 20 12/15/79 8:00 0.230 32 1.59 0.370 0.210 40 12/26/80 0:00 0.228 33 1.54 0.350 0.417 12 10/06/81 15:00 0.225 34 1.49 0.330 0.311 19 1/05/83 8:00 0.220 35 1.45 0.310 0.220 37 1/03/84 1:00 0.220 36 1.41 0.291 0.109 47 2/11/85 3:00 0.220 37 1.37 0.271
0.504 7 1/18/86 16:00 0.218 38 1.33 0.251 0.439 10 11/24/86 4:00 0.213 39 1.30 0.231 0.177 42 1/14/88 12:00 0.210 40 1.27 0.211 0.106 48 12/30/88 5:00 0.179 41 1.24 0.191 0.737 1 1/09/90 9:00 0.177 42 1.21 0.171 0.621 4 11/24/90 8:00 0.174 43 1.18 0.151 0.239 27 1/27/92 17:00 0.158 44 1.15 0.131 0.218 38 3/22/93 23:00 0.154 45 1.12 0.111 0.077 49 2/17/94 18:00 0.123 46 1.10 0.091
0.314 18 2/19/95 18:00 0.109 47 1.08 0.071
0.616 5 2/08/96 10:00 0.106 48 1.05 0.051 0.376 15 1/02/97 6:00 0.077 49 1.03 0.031 0.158 44 10/30/97 7:00 0.070 50 1.01 0.011 Computed Peaks 0.834 100.00 0.990 Computed Peaks 0.742 50.00 0.980 Computed Peaks 0.649 25.00 0.960 Computed Peaks 0.523 10.00 0.900 Computed Peaks 0.496 8.00 0.875
Computed Peaks 0.423 5.00 0.800
Computed Peaks 0.275 2.00 0.500 Computed Peaks 0.182 1.30 0.231
DevCombined Flow Frequency Analysis
Dev.tsf + offsite.tsf = DevCombined.tsf Flow Frequency Analysis LogPearson III Coefficients Time Series File:devcombined.tsf Mean= 0.101 StdDev= 0.125 Project Location:Sea-Tac Skew= 0.395 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period
1.33 20 2/16/49 21:00 2.54 1 89.50 0.989 2.47 2 3/03/50 16:00 2.47 2 32.13 0.969 1.42 18 2/09/51 2:00 2.27 3 19.58 0.949 0.957 43 10/15/51 13:00 2.10 4 14.08 0.929 0.967 42 3/24/53 15:00 1.78 5 10.99 0.909 1.22 26 12/19/53 19:00 1.75 6 9.01 0.889 1.22 25 11/25/54 2:00 1.68 7 7.64 0.869 1.23 24 12/20/55 17:00 1.66 8 6.63 0.849 1.50 13 12/09/56 14:00 1.64 9 5.86 0.829
1.27 21 12/25/57 16:00 1.62 10 5.24 0.809
0.922 46 1/26/59 20:00 1.52 11 4.75 0.789 1.25 22 11/20/59 5:00 1.51 12 4.34 0.769 1.10 33 2/14/61 21:00 1.50 13 3.99 0.749 1.03 39 11/22/61 2:00 1.50 14 3.70 0.729 1.11 31 12/15/62 2:00 1.47 15 3.44 0.709 1.20 28 12/31/63 23:00 1.46 16 3.22 0.690 1.06 38 12/21/64 4:00 1.44 17 3.03 0.670 1.09 35 1/05/66 16:00 1.42 18 2.85 0.650 1.66 8 11/13/66 19:00 1.40 19 2.70 0.630 1.75 6 8/24/68 16:00 1.33 20 2.56 0.610
1.00 41 12/03/68 16:00 1.27 21 2.44 0.590 1.11 32 1/13/70 22:00 1.25 22 2.32 0.570 1.07 36 12/06/70 8:00 1.24 23 2.22 0.550 1.78 5 2/27/72 7:00 1.23 24 2.13 0.530 0.954 44 1/13/73 2:00 1.22 25 2.04 0.510 1.21 27 11/28/73 9:00 1.22 26 1.96 0.490 1.64 9 12/26/74 23:00 1.21 27 1.89 0.470 1.01 40 12/02/75 20:00 1.20 28 1.82 0.450 1.06 37 8/26/77 2:00 1.18 29 1.75 0.430
1.52 11 9/22/78 19:00 1.14 30 1.70 0.410
1.24 23 9/08/79 15:00 1.11 31 1.64 0.390 1.46 16 12/14/79 21:00 1.11 32 1.59 0.370 1.47 15 11/21/80 11:00 1.10 33 1.54 0.350 2.10 4 10/06/81 15:00 1.10 34 1.49 0.330 1.40 19 10/28/82 16:00 1.09 35 1.45 0.310 1.18 29 1/03/84 1:00 1.07 36 1.41 0.291 0.939 45 6/06/85 22:00 1.06 37 1.37 0.271 1.50 14 1/18/86 16:00 1.06 38 1.33 0.251
1.68 7 10/26/86 0:00 1.03 39 1.30 0.231
0.732 49 1/14/88 0:00 1.01 40 1.27 0.211 0.882 47 8/21/89 17:00 1.00 41 1.24 0.191 2.54 1 1/09/90 6:00 0.967 42 1.21 0.171 2.27 3 11/24/90 8:00 0.957 43 1.18 0.151 1.14 30 1/27/92 15:00 0.954 44 1.15 0.131 0.679 50 12/10/92 6:00 0.939 45 1.12 0.111 0.782 48 11/30/93 22:00 0.922 46 1.10 0.091 1.10 34 11/30/94 4:00 0.882 47 1.08 0.071 1.62 10 2/08/96 10:00 0.782 48 1.05 0.051 1.44 17 1/02/97 6:00 0.732 49 1.03 0.031 1.51 12 10/04/97 15:00 0.679 50 1.01 0.011 Computed Peaks 2.68 100.00 0.990 Computed Peaks 2.42 50.00 0.980 Computed Peaks 2.17 25.00 0.960 Computed Peaks 1.84 10.00 0.900 Computed Peaks 1.78 8.00 0.875 Computed Peaks 1.60 5.00 0.800 Computed Peaks 1.24 2.00 0.500 Computed Peaks 1.01 1.30 0.231
Flows Used For Target Duration Curve Calculation
First Interval: 50% of 2-year predev.tsf + 2-year offsite.tsf (0.5 * 0.210) + 0.088 = 0.193 cfs
50-year Flow: 50-year predev.tsf + 50-year offsite.tsf 0.598 + 0.205 = 0.803 cfs Interval Size: (50-year – First Interval) / (36 – 1) (0.803 – 0.193) / 35 = 0.0174
Greenleaf Pond Facility
Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 3.00 H:1V
Pond Bottom Length: 86.00 ft Pond Bottom Width: 42.00 ft Pond Bottom Area: 3612. sq. ft Top Area at 1 ft. FB: 14522. sq. ft 0.333 acres Effective Storage Depth: 8.75 ft Stage 0 Elevation: 0.00 ft Storage Volume: 69044. cu. ft 1.585 ac-ft
Riser Head: 8.75 ft
Riser Diameter: 18.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1.57 0.197 2 7.00 2.75 0.271 6.0 3 8.00 2.00 0.094 4.0 Top Notch Weir: None Outflow Rating Curve: None
Stage Elevation Storage Discharge Percolation Surf Area (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) (sq. ft) 0.00 0.00 0. 0.000 0.000 0.00 3612. 0.02 0.02 72. 0.002 0.009 0.00 3627. 0.03 0.03 109. 0.002 0.012 0.00 3635. 0.05 0.05 182. 0.004 0.015 0.00 3650.
0.07 0.07 255. 0.006 0.017 0.00 3666. 0.08 0.08 291. 0.007 0.019 0.00 3674.
0.10 0.10 365. 0.008 0.021 0.00 3689.
0.11 0.11 402. 0.009 0.023 0.00 3697. 0.13 0.13 476. 0.011 0.024 0.00 3712. 0.30 0.30 1119. 0.026 0.037 0.00 3846. 0.47 0.47 1784. 0.041 0.046 0.00 3981. 0.65 0.65 2513. 0.058 0.054 0.00 4126. 0.82 0.82 3227. 0.074 0.060 0.00 4266. 0.99 0.99 3964. 0.091 0.066 0.00 4408. 1.16 1.16 4725. 0.108 0.072 0.00 4551. 1.33 1.33 5511. 0.127 0.077 0.00 4697. 1.50 1.50 6323. 0.145 0.082 0.00 4845.
1.67 1.67 7159. 0.164 0.086 0.00 4995. 1.85 1.85 8072. 0.185 0.091 0.00 5156. 2.02 2.02 8962. 0.206 0.095 0.00 5310. 2.19 2.19 9878. 0.227 0.099 0.00 5467. 2.36 2.36 10821. 0.248 0.103 0.00 5625. 2.53 2.53 11791. 0.271 0.106 0.00 5785. 2.70 2.70 12788. 0.294 0.110 0.00 5948. 2.88 2.88 13874. 0.319 0.113 0.00 6122. 3.05 3.05 14929. 0.343 0.117 0.00 6289.
3.22 3.22 16013. 0.368 0.120 0.00 6458.
3.39 3.39 17125. 0.393 0.123 0.00 6629. 3.56 3.56 18267. 0.419 0.126 0.00 6802. 3.73 3.73 19438. 0.446 0.129 0.00 6978. 3.91 3.91 20711. 0.475 0.132 0.00 7165. 4.08 4.08 21944. 0.504 0.135 0.00 7345. 4.25 4.25 23208. 0.533 0.138 0.00 7526. 4.42 4.42 24503. 0.563 0.140 0.00 7710. 4.59 4.59 25830. 0.593 0.143 0.00 7896.
4.76 4.76 27188. 0.624 0.146 0.00 8083.
4.93 4.93 28578. 0.656 0.148 0.00 8273. 5.11 5.11 30086. 0.691 0.151 0.00 8477. 5.28 5.28 31543. 0.724 0.153 0.00 8671. 5.45 5.45 33034. 0.758 0.156 0.00 8867. 5.62 5.62 34558. 0.793 0.158 0.00 9065. 5.79 5.79 36116. 0.829 0.161 0.00 9266. 5.96 5.96 37708. 0.866 0.163 0.00 9468. 6.14 6.14 39432. 0.905 0.165 0.00 9685. 6.31 6.31 41096. 0.943 0.168 0.00 9891. 6.48 6.48 42795. 0.982 0.170 0.00 10100. 6.65 6.65 44530. 1.022 0.172 0.00 10311. 6.82 6.82 46301. 1.063 0.174 0.00 10524. 6.99 6.99 48109. 1.104 0.177 0.00 10739. 7.00 7.00 48216. 1.107 0.177 0.00 10752. 7.03 7.03 48539. 1.114 0.179 0.00 10790. 7.06 7.06 48863. 1.122 0.185 0.00 10828. 7.09 7.09 49189. 1.129 0.195 0.00 10867. 7.11 7.11 49406. 1.134 0.209 0.00 10892. 7.14 7.14 49734. 1.142 0.225 0.00 10931.
7.17 7.17 50062. 1.149 0.246 0.00 10969. 7.20 7.20 50392. 1.157 0.269 0.00 11008. 7.23 7.23 50723. 1.164 0.278 0.00 11046. 7.40 7.40 52619. 1.208 0.312 0.00 11267. 7.57 7.57 54554. 1.252 0.339 0.00 11489.
7.74 7.74 56526. 1.298 0.363 0.00 11713.
7.92 7.92 58655. 1.347 0.384 0.00 11953. 8.00 8.00 59616. 1.369 0.394 0.00 12060. 8.02 8.02 59857. 1.374 0.397 0.00 12087. 8.04 8.04 60099. 1.380 0.402 0.00 12114. 8.06 8.06 60342. 1.385 0.408 0.00 12141. 8.08 8.08 60585. 1.391 0.416 0.00 12168. 8.10 8.10 60829. 1.396 0.426 0.00 12195. 8.12 8.12 61073. 1.402 0.437 0.00 12222. 8.15 8.15 61440. 1.410 0.448 0.00 12262. 8.17 8.17 61686. 1.416 0.457 0.00 12290.
8.19 8.19 61932. 1.422 0.462 0.00 12317. 8.36 8.36 64045. 1.470 0.497 0.00 12549. 8.53 8.53 66198. 1.520 0.528 0.00 12782. 8.70 8.70 68391. 1.570 0.556 0.00 13018. 8.75 8.75 69044. 1.585 0.563 0.00 13088. 8.85 8.85 70360. 1.615 1.040 0.00 13228. 8.95 8.95 71690. 1.646 1.900 0.00 13369. 9.05 9.05 73034. 1.677 3.010 0.00 13511. 9.15 9.15 74392. 1.708 4.310 0.00 13653.
9.25 9.25 75764. 1.739 5.800 0.00 13796.
9.35 9.35 77151. 1.771 7.240 0.00 13940. 9.45 9.45 78552. 1.803 7.780 0.00 14084. 9.55 9.55 79968. 1.836 8.280 0.00 14230. 9.65 9.65 81398. 1.869 8.750 0.00 14376. 9.75 9.75 82843. 1.902 9.200 0.00 14522. 9.85 9.85 84303. 1.935 9.630 0.00 14670. 9.95 9.95 85777. 1.969 10.040 0.00 14818. 10.05 10.05 87266. 2.003 10.430 0.00 14966.
10.15 10.15 88771. 2.038 10.800 0.00 15116.
10.25 10.25 90290. 2.073 11.170 0.00 15266. 10.35 10.35 91824. 2.108 11.520 0.00 15417. 10.45 10.45 93373. 2.144 11.860 0.00 15569. 10.55 10.55 94938. 2.179 12.190 0.00 15721. 10.65 10.65 96517. 2.216 12.520 0.00 15874. Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 1.42 0.74 8.79 8.79 69546. 1.597 2 1.62 0.71 8.78 8.78 69455. 1.594 3 2.54 0.54 8.57 8.57 66757. 1.533 4 2.10 0.39 7.94 7.94 58867. 1.351 5 1.44 0.44 8.14 8.14 61281. 1.407 6 1.78 0.35 7.63 7.63 55223. 1.268 7 1.14 0.14 4.39 4.39 24311. 0.558 8 1.09 0.15 5.07 5.07 29717. 0.682 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc
1 0.74 0.14 ******** ******* 0.80 2 0.71 0.15 ******** 0.78 0.75 3 0.54 0.23 ******** ******* 0.62 4 0.39 0.22 ******** ******* 0.50 5 0.44 0.14 ******** ******* 0.49
6 0.35 0.17 ******** ******* 0.39
7 0.14 0.12 ******** ******* 0.24 8 0.15 0.12 ******** ******* 0.22 ---------------------------------- Route Time Series through Facility Inflow Time Series File:devcombined.tsf Outflow Time Series File:rdout POC Time Series File:dsout Inflow/Outflow Analysis
Peak Inflow Discharge: 2.54 CFS at 6:00 on Jan 9 in 1990 Peak Outflow Discharge: 0.744 CFS at 19:00 on Feb 9 in 1951 Peak Reservoir Stage: 8.79 Ft Peak Reservoir Elev: 8.79 Ft Peak Reservoir Storage: 69546. Cu-Ft : 1.597 Ac-Ft Add Time Series:bypass.tsf Peak Summed Discharge: 0.802 CFS at 19:00 on Feb 9 in 1951
Point of Compliance File:dsout.tsf
Flow Frequency Analysis LogPearson III Coefficients Time Series File:rdout.tsf Mean= -0.704 StdDev= 0.214 Project Location:Sea-Tac Skew= 1.397 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.146 38 2/17/49 9:00 0.744 8.79 1 89.50 0.989
0.175 13 3/05/50 11:00 0.712 8.78 2 32.13 0.969
0.744 1 2/09/51 19:00 0.535 8.57 3 19.58 0.949 0.132 46 2/01/52 4:00 0.504 8.40 4 14.08 0.929 0.149 37 1/12/53 8:00 0.499 8.37 5 10.99 0.909 0.164 28 1/06/54 13:00 0.443 8.14 6 9.01 0.889 0.169 18 2/08/55 12:00 0.410 8.06 7 7.64 0.869 0.307 12 12/22/55 15:00 0.386 7.94 8 6.63 0.849 0.162 30 2/26/57 4:00 0.381 7.90 9 5.86 0.829 0.166 24 1/17/58 10:00 0.347 7.63 10 5.24 0.809 0.150 35 1/24/59 16:00 0.320 7.45 11 4.75 0.789 0.499 5 11/21/59 2:00 0.307 7.37 12 4.34 0.769 0.166 25 11/24/60 18:00 0.175 6.87 13 3.99 0.749 0.126 47 1/03/62 9:00 0.172 6.69 14 3.70 0.729 0.162 29 11/27/62 1:00 0.172 6.63 15 3.44 0.709 0.153 31 11/15/63 7:00 0.170 6.50 16 3.22 0.690 0.172 15 12/01/64 10:00 0.170 6.46 17 3.03 0.670 0.150 33 12/29/65 10:00 0.169 6.41 18 2.85 0.650 0.167 22 12/13/66 18:00 0.169 6.38 19 2.70 0.630 0.151 32 1/20/68 21:00 0.169 6.36 20 2.56 0.610 0.145 40 12/04/68 3:00 0.168 6.33 21 2.44 0.590
0.150 36 1/14/70 17:00 0.167 6.26 22 2.32 0.570 0.170 16 12/07/70 11:00 0.167 6.24 23 2.22 0.550 0.347 10 2/28/72 19:00 0.166 6.20 24 2.13 0.530 0.170 17 12/27/72 19:00 0.166 6.18 25 2.04 0.510 0.169 19 1/16/74 19:00 0.165 6.12 26 1.96 0.490
0.164 27 12/27/74 14:00 0.164 6.02 27 1.89 0.470
0.167 23 12/04/75 4:00 0.164 6.01 28 1.82 0.450 0.118 49 8/26/77 6:00 0.162 5.90 29 1.75 0.430 0.165 26 12/15/77 20:00 0.162 5.85 30 1.70 0.410 0.124 48 2/12/79 18:00 0.153 5.24 31 1.64 0.390 0.410 7 12/17/79 20:00 0.151 5.11 32 1.59 0.370 0.150 34 12/27/80 8:00 0.150 5.07 33 1.54 0.350 0.386 8 10/06/81 18:00 0.150 5.05 34 1.49 0.330 0.168 21 1/06/83 15:00 0.150 5.05 35 1.45 0.310 0.139 44 12/10/83 18:00 0.150 5.03 36 1.41 0.291 0.146 39 11/04/84 0:00 0.149 4.99 37 1.37 0.271
0.320 11 1/19/86 0:00 0.146 4.76 38 1.33 0.251 0.381 9 11/24/86 8:00 0.146 4.74 39 1.30 0.231 0.142 43 1/15/88 7:00 0.145 4.72 40 1.27 0.211 0.137 45 11/05/88 21:00 0.145 4.70 41 1.24 0.191 0.535 3 1/09/90 12:00 0.144 4.63 42 1.21 0.171 0.504 4 4/05/91 6:00 0.142 4.55 43 1.18 0.151 0.169 20 1/31/92 7:00 0.139 4.30 44 1.15 0.131 0.144 42 3/23/93 13:00 0.137 4.18 45 1.12 0.111 0.118 50 2/17/94 21:00 0.132 3.90 46 1.10 0.091
0.172 14 2/20/95 19:00 0.126 3.56 47 1.08 0.071
0.712 2 2/09/96 3:00 0.124 3.44 48 1.05 0.051 0.443 6 1/02/97 12:00 0.118 3.09 49 1.03 0.031 0.145 41 10/30/97 12:00 0.118 3.08 50 1.01 0.011 Computed Peaks 0.991 8.84 100.00 0.990 Computed Peaks 0.750 8.79 50.00 0.980 Computed Peaks 0.564 8.75 25.00 0.960 Computed Peaks 0.382 7.90 10.00 0.900 Computed Peaks 0.353 7.67 8.00 0.875
Computed Peaks 0.280 7.24 5.00 0.800
Computed Peaks 0.177 6.98 2.00 0.500 Computed Peaks 0.135 4.08 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:dsout.tsf Mean= -0.547 StdDev= 0.159 Project Location:Sea-Tac Skew= 1.358 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.260 22 2/16/49 21:00 0.802 1 89.50 0.989 0.323 13 3/03/50 16:00 0.748 2 32.13 0.969 0.802 1 2/09/51 19:00 0.618 3 19.58 0.949 0.216 43 1/30/52 8:00 0.556 4 14.08 0.929 0.224 37 1/11/53 4:00 0.552 5 10.99 0.909 0.223 38 12/19/53 19:00 0.499 6 9.01 0.889 0.259 23 2/07/55 17:00 0.488 7 7.64 0.869 0.338 12 12/22/55 14:00 0.446 8 6.63 0.849 0.285 16 12/09/56 14:00 0.434 9 5.86 0.829 0.241 27 1/16/58 16:00 0.392 10 5.24 0.809
0.228 36 1/26/59 20:00 0.355 11 4.75 0.789 0.552 5 11/21/59 1:00 0.338 12 4.34 0.769 0.262 20 11/24/60 8:00 0.323 13 3.99 0.749 0.204 46 11/22/61 2:00 0.299 14 3.70 0.729 0.221 40 12/15/62 2:00 0.291 15 3.44 0.709
0.219 42 12/31/63 23:00 0.285 16 3.22 0.690
0.231 33 11/30/64 5:00 0.281 17 3.03 0.670 0.222 39 1/05/66 16:00 0.274 18 2.85 0.650 0.291 15 11/13/66 19:00 0.274 19 2.70 0.630 0.281 17 8/24/68 16:00 0.262 20 2.56 0.610 0.229 35 12/03/68 16:00 0.260 21 2.44 0.590 0.237 29 1/13/70 23:00 0.260 22 2.32 0.570 0.260 21 12/06/70 8:00 0.259 23 2.22 0.550 0.392 10 2/28/72 17:00 0.249 24 2.13 0.530 0.233 32 12/26/72 2:00 0.248 25 2.04 0.510 0.242 26 11/11/73 17:00 0.242 26 1.96 0.490
0.299 14 12/26/74 23:00 0.241 27 1.89 0.470 0.236 30 12/02/75 20:00 0.239 28 1.82 0.450 0.234 31 8/26/77 2:00 0.237 29 1.75 0.430 0.274 19 9/22/78 19:00 0.236 30 1.70 0.410 0.194 49 10/23/78 21:00 0.234 31 1.64 0.390 0.446 8 12/17/79 19:00 0.233 32 1.59 0.370 0.274 18 11/21/80 11:00 0.231 33 1.54 0.350 0.499 6 10/06/81 15:00 0.230 34 1.49 0.330 0.248 25 10/28/82 17:00 0.229 35 1.45 0.310
0.214 45 1/03/84 1:00 0.228 36 1.41 0.291
0.214 44 6/06/85 23:00 0.224 37 1.37 0.271 0.355 11 1/18/86 21:00 0.223 38 1.33 0.251 0.434 9 11/24/86 6:00 0.222 39 1.30 0.231 0.203 47 1/14/88 12:00 0.221 40 1.27 0.211 0.219 41 11/05/88 14:00 0.219 41 1.24 0.191 0.618 3 1/09/90 9:00 0.219 42 1.21 0.171 0.556 4 4/05/91 2:00 0.216 43 1.18 0.151 0.230 34 1/27/92 17:00 0.214 44 1.15 0.131
0.197 48 3/22/93 22:00 0.214 45 1.12 0.111
0.174 50 2/17/94 18:00 0.204 46 1.10 0.091 0.239 28 2/19/95 17:00 0.203 47 1.08 0.071 0.748 2 2/09/96 3:00 0.197 48 1.05 0.051 0.488 7 1/02/97 9:00 0.194 49 1.03 0.031 0.249 24 10/04/97 15:00 0.174 50 1.01 0.011 Computed Peaks 0.929 100.00 0.990 Computed Peaks 0.758 50.00 0.980 Computed Peaks 0.616 25.00 0.960 Computed Peaks 0.463 10.00 0.900 Computed Peaks 0.437 8.00 0.875 Computed Peaks 0.368 5.00 0.800 Computed Peaks 0.262 2.00 0.500 Computed Peaks 0.214 1.30 0.231 Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.011 288935 65.967 65.967 34.033 0.340E+00 0.032 37852 8.642 74.609 25.391 0.254E+00
0.052 31854 7.273 81.882 18.118 0.181E+00 0.073 27321 6.238 88.119 11.881 0.119E+00 0.094 19673 4.492 92.611 7.389 0.739E-01 0.115 14214 3.245 95.856 4.144 0.414E-01 0.136 9325 2.129 97.985 2.015 0.202E-01
0.157 5302 1.211 99.195 0.805 0.805E-02
0.178 2801 0.639 99.835 0.165 0.165E-02 0.199 122 0.028 99.863 0.137 0.137E-02 0.220 55 0.013 99.875 0.125 0.125E-02 0.241 41 0.009 99.885 0.115 0.115E-02 0.262 27 0.006 99.891 0.109 0.109E-02 0.283 34 0.008 99.899 0.101 0.101E-02 0.304 62 0.014 99.913 0.087 0.872E-03 0.325 72 0.016 99.929 0.071 0.708E-03 0.346 77 0.018 99.947 0.053 0.532E-03 0.366 52 0.012 99.959 0.041 0.413E-03
0.387 62 0.014 99.973 0.027 0.272E-03 0.408 31 0.007 99.980 0.020 0.201E-03 0.429 11 0.003 99.982 0.018 0.176E-03 0.450 9 0.002 99.984 0.016 0.155E-03 0.471 11 0.003 99.987 0.013 0.130E-03 0.492 12 0.003 99.990 0.010 0.103E-03 0.513 18 0.004 99.994 0.006 0.616E-04 0.534 10 0.002 99.996 0.004 0.388E-04 0.555 9 0.002 99.998 0.002 0.183E-04
0.576 3 0.001 99.999 0.001 0.114E-04
0.597 1 0.000 99.999 0.001 0.913E-05 0.618 0 0.000 99.999 0.001 0.913E-05 0.639 1 0.000 99.999 0.001 0.685E-05 0.660 0 0.000 99.999 0.001 0.685E-05 0.680 0 0.000 99.999 0.001 0.685E-05 0.701 0 0.000 99.999 0.001 0.685E-05 0.722 2 0.000 100.000 0.000 0.228E-05 0.743 0 0.000 100.000 0.000 0.228E-05
Flow Duration from Time Series File:dsout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.011 288697 65.913 65.913 34.087 0.341E+00 0.034 37177 8.488 74.400 25.600 0.256E+00 0.057 32192 7.350 81.750 18.250 0.182E+00 0.079 27178 6.205 87.955 12.045 0.120E+00 0.102 19791 4.518 92.474 7.526 0.753E-01 0.124 14342 3.274 95.748 4.252 0.425E-01 0.147 9422 2.151 97.899 2.101 0.210E-01 0.169 5393 1.231 99.131 0.869 0.869E-02 0.192 2244 0.512 99.643 0.357 0.357E-02 0.214 632 0.144 99.787 0.213 0.213E-02 0.237 244 0.056 99.843 0.157 0.157E-02 0.259 114 0.026 99.869 0.131 0.131E-02 0.282 69 0.016 99.885 0.115 0.115E-02 0.305 76 0.017 99.902 0.098 0.979E-03 0.327 71 0.016 99.918 0.082 0.817E-03 0.350 73 0.017 99.935 0.065 0.651E-03
0.372 68 0.016 99.950 0.050 0.495E-03 0.395 57 0.013 99.963 0.037 0.365E-03 0.417 38 0.009 99.972 0.028 0.279E-03 0.440 23 0.005 99.977 0.023 0.226E-03 0.462 19 0.004 99.982 0.018 0.183E-03
0.485 15 0.003 99.985 0.015 0.148E-03
0.507 12 0.003 99.988 0.012 0.121E-03 0.530 14 0.003 99.991 0.009 0.890E-04 0.553 14 0.003 99.994 0.006 0.571E-04 0.575 10 0.002 99.997 0.003 0.342E-04 0.598 3 0.001 99.997 0.003 0.274E-04 0.620 6 0.001 99.999 0.001 0.137E-04 0.643 1 0.000 99.999 0.001 0.114E-04 0.665 1 0.000 99.999 0.001 0.913E-05 0.688 0 0.000 99.999 0.001 0.913E-05 0.710 1 0.000 99.999 0.001 0.685E-05
0.733 1 0.000 100.000 0.000 0.457E-05 0.756 1 0.000 100.000 0.000 0.228E-05 0.778 0 0.000 100.000 0.000 0.228E-05 0.801 0 0.000 100.000 0.000 0.228E-05 Duration Comparison Anaylsis Base File: predevcombined.tsf New File: dsout.tsf Cutoff Units: Discharge in CFS
-----Fraction of Time----- ---------Check of Tolerance-------
Cutoff Base New %Change Probability Base New %Change 0.192 | 0.36E-02 0.35E-02 -1.5 | 0.36E-02 0.192 0.192 -0.3 0.234 | 0.21E-02 0.16E-02 -21.8 | 0.21E-02 0.234 0.216 -7.7 0.276 | 0.12E-02 0.12E-02 -4.2 | 0.12E-02 0.276 0.269 -2.4 0.318 | 0.77E-03 0.89E-03 16.4 | 0.77E-03 0.318 0.334 5.2 0.360 | 0.50E-03 0.59E-03 16.8 | 0.50E-03 0.360 0.372 3.4 0.401 | 0.35E-03 0.33E-03 -4.6 | 0.35E-03 0.401 0.398 -1.0 0.443 | 0.23E-03 0.22E-03 -3.0 | 0.23E-03 0.443 0.440 -0.8
0.485 | 0.13E-03 0.15E-03 10.2 | 0.13E-03 0.485 0.497 2.4
0.527 | 0.75E-04 0.91E-04 21.2 | 0.75E-04 0.527 0.540 2.5 0.569 | 0.46E-04 0.41E-04 -10.0 | 0.46E-04 0.569 0.561 -1.4 0.611 | 0.21E-04 0.18E-04 -11.1 | 0.21E-04 0.611 0.609 -0.2 0.653 | 0.11E-04 0.91E-05 -20.0 | 0.11E-04 0.653 0.645 -1.2 0.694 | 0.11E-04 0.68E-05 -40.0 | 0.11E-04 0.694 0.645 -7.2 0.736 | 0.23E-05 0.46E-05 100.0 | 0.23E-05 0.736 0.800 8.7 Maximum positive excursion = 0.072 cfs ( 9.9%) occurring at 0.728 cfs on the Base Data:predevcombined.tsf and at 0.800 cfs on the New Data:dsout.tsf Maximum negative excursion = 0.021 cfs ( -8.5%) occurring at 0.245 cfs on the Base Data:predevcombined.tsf and at 0.224 cfs on the New Data:dsout.tsf ---------------------------------- Route Time Series through Facility Inflow Time Series File:devcombined.tsf Outflow Time Series File:rdout
POC Time Series File:dsout Inflow/Outflow Analysis Peak Inflow Discharge: 2.54 CFS at 6:00 on Jan 9 in 1990 Peak Outflow Discharge: 0.744 CFS at 19:00 on Feb 9 in 1951
Peak Reservoir Stage: 8.79 Ft
Peak Reservoir Elev: 8.79 Ft Peak Reservoir Storage: 69546. Cu-Ft : 1.597 Ac-Ft Add Time Series:bypass.tsf Peak Summed Discharge: 0.802 CFS at 19:00 on Feb 9 in 1951 Point of Compliance File:dsout.tsf Flow Frequency Analysis LogPearson III Coefficients Time Series File:rdout.tsf Mean= -0.704 StdDev= 0.214 Project Location:Sea-Tac Skew= 1.397
---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.146 38 2/17/49 9:00 0.744 8.79 1 89.50 0.989 0.175 13 3/05/50 11:00 0.712 8.78 2 32.13 0.969 0.744 1 2/09/51 19:00 0.535 8.57 3 19.58 0.949 0.132 46 2/01/52 4:00 0.504 8.40 4 14.08 0.929 0.149 37 1/12/53 8:00 0.499 8.37 5 10.99 0.909
0.164 28 1/06/54 13:00 0.443 8.14 6 9.01 0.889
0.169 18 2/08/55 12:00 0.410 8.06 7 7.64 0.869 0.307 12 12/22/55 15:00 0.386 7.94 8 6.63 0.849 0.162 30 2/26/57 4:00 0.381 7.90 9 5.86 0.829 0.166 24 1/17/58 10:00 0.347 7.63 10 5.24 0.809 0.150 35 1/24/59 16:00 0.320 7.45 11 4.75 0.789 0.499 5 11/21/59 2:00 0.307 7.37 12 4.34 0.769 0.166 25 11/24/60 18:00 0.175 6.87 13 3.99 0.749 0.126 47 1/03/62 9:00 0.172 6.69 14 3.70 0.729
0.162 29 11/27/62 1:00 0.172 6.63 15 3.44 0.709
0.153 31 11/15/63 7:00 0.170 6.50 16 3.22 0.690 0.172 15 12/01/64 10:00 0.170 6.46 17 3.03 0.670 0.150 33 12/29/65 10:00 0.169 6.41 18 2.85 0.650 0.167 22 12/13/66 18:00 0.169 6.38 19 2.70 0.630 0.151 32 1/20/68 21:00 0.169 6.36 20 2.56 0.610 0.145 40 12/04/68 3:00 0.168 6.33 21 2.44 0.590 0.150 36 1/14/70 17:00 0.167 6.26 22 2.32 0.570 0.170 16 12/07/70 11:00 0.167 6.24 23 2.22 0.550 0.347 10 2/28/72 19:00 0.166 6.20 24 2.13 0.530 0.170 17 12/27/72 19:00 0.166 6.18 25 2.04 0.510 0.169 19 1/16/74 19:00 0.165 6.12 26 1.96 0.490 0.164 27 12/27/74 14:00 0.164 6.02 27 1.89 0.470 0.167 23 12/04/75 4:00 0.164 6.01 28 1.82 0.450 0.118 49 8/26/77 6:00 0.162 5.90 29 1.75 0.430 0.165 26 12/15/77 20:00 0.162 5.85 30 1.70 0.410 0.124 48 2/12/79 18:00 0.153 5.24 31 1.64 0.390 0.410 7 12/17/79 20:00 0.151 5.11 32 1.59 0.370 0.150 34 12/27/80 8:00 0.150 5.07 33 1.54 0.350 0.386 8 10/06/81 18:00 0.150 5.05 34 1.49 0.330
0.168 21 1/06/83 15:00 0.150 5.05 35 1.45 0.310 0.139 44 12/10/83 18:00 0.150 5.03 36 1.41 0.291 0.146 39 11/04/84 0:00 0.149 4.99 37 1.37 0.271 0.320 11 1/19/86 0:00 0.146 4.76 38 1.33 0.251 0.381 9 11/24/86 8:00 0.146 4.74 39 1.30 0.231
0.142 43 1/15/88 7:00 0.145 4.72 40 1.27 0.211
0.137 45 11/05/88 21:00 0.145 4.70 41 1.24 0.191 0.535 3 1/09/90 12:00 0.144 4.63 42 1.21 0.171 0.504 4 4/05/91 6:00 0.142 4.55 43 1.18 0.151 0.169 20 1/31/92 7:00 0.139 4.30 44 1.15 0.131 0.144 42 3/23/93 13:00 0.137 4.18 45 1.12 0.111 0.118 50 2/17/94 21:00 0.132 3.90 46 1.10 0.091 0.172 14 2/20/95 19:00 0.126 3.56 47 1.08 0.071 0.712 2 2/09/96 3:00 0.124 3.44 48 1.05 0.051 0.443 6 1/02/97 12:00 0.118 3.09 49 1.03 0.031 0.145 41 10/30/97 12:00 0.118 3.08 50 1.01 0.011
Computed Peaks 0.991 8.84 100.00 0.990 Computed Peaks 0.750 8.79 50.00 0.980 Computed Peaks 0.564 8.75 25.00 0.960 Computed Peaks 0.382 7.90 10.00 0.900 Computed Peaks 0.353 7.67 8.00 0.875 Computed Peaks 0.280 7.24 5.00 0.800 Computed Peaks 0.177 6.98 2.00 0.500 Computed Peaks 0.135 4.08 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients
Time Series File:dsout.tsf Mean= -0.547 StdDev= 0.159
Project Location:Sea-Tac Skew= 1.358 ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.260 22 2/16/49 21:00 0.802 1 89.50 0.989 0.323 13 3/03/50 16:00 0.748 2 32.13 0.969 0.802 1 2/09/51 19:00 0.618 3 19.58 0.949
0.216 43 1/30/52 8:00 0.556 4 14.08 0.929
0.224 37 1/11/53 4:00 0.552 5 10.99 0.909 0.223 38 12/19/53 19:00 0.499 6 9.01 0.889 0.259 23 2/07/55 17:00 0.488 7 7.64 0.869 0.338 12 12/22/55 14:00 0.446 8 6.63 0.849 0.285 16 12/09/56 14:00 0.434 9 5.86 0.829 0.241 27 1/16/58 16:00 0.392 10 5.24 0.809 0.228 36 1/26/59 20:00 0.355 11 4.75 0.789 0.552 5 11/21/59 1:00 0.338 12 4.34 0.769 0.262 20 11/24/60 8:00 0.323 13 3.99 0.749 0.204 46 11/22/61 2:00 0.299 14 3.70 0.729 0.221 40 12/15/62 2:00 0.291 15 3.44 0.709 0.219 42 12/31/63 23:00 0.285 16 3.22 0.690 0.231 33 11/30/64 5:00 0.281 17 3.03 0.670 0.222 39 1/05/66 16:00 0.274 18 2.85 0.650 0.291 15 11/13/66 19:00 0.274 19 2.70 0.630 0.281 17 8/24/68 16:00 0.262 20 2.56 0.610 0.229 35 12/03/68 16:00 0.260 21 2.44 0.590 0.237 29 1/13/70 23:00 0.260 22 2.32 0.570 0.260 21 12/06/70 8:00 0.259 23 2.22 0.550
0.392 10 2/28/72 17:00 0.249 24 2.13 0.530 0.233 32 12/26/72 2:00 0.248 25 2.04 0.510 0.242 26 11/11/73 17:00 0.242 26 1.96 0.490 0.299 14 12/26/74 23:00 0.241 27 1.89 0.470 0.236 30 12/02/75 20:00 0.239 28 1.82 0.450
0.234 31 8/26/77 2:00 0.237 29 1.75 0.430
0.274 19 9/22/78 19:00 0.236 30 1.70 0.410 0.194 49 10/23/78 21:00 0.234 31 1.64 0.390 0.446 8 12/17/79 19:00 0.233 32 1.59 0.370 0.274 18 11/21/80 11:00 0.231 33 1.54 0.350 0.499 6 10/06/81 15:00 0.230 34 1.49 0.330 0.248 25 10/28/82 17:00 0.229 35 1.45 0.310 0.214 45 1/03/84 1:00 0.228 36 1.41 0.291 0.214 44 6/06/85 23:00 0.224 37 1.37 0.271 0.355 11 1/18/86 21:00 0.223 38 1.33 0.251 0.434 9 11/24/86 6:00 0.222 39 1.30 0.231
0.203 47 1/14/88 12:00 0.221 40 1.27 0.211 0.219 41 11/05/88 14:00 0.219 41 1.24 0.191 0.618 3 1/09/90 9:00 0.219 42 1.21 0.171 0.556 4 4/05/91 2:00 0.216 43 1.18 0.151 0.230 34 1/27/92 17:00 0.214 44 1.15 0.131 0.197 48 3/22/93 22:00 0.214 45 1.12 0.111 0.174 50 2/17/94 18:00 0.204 46 1.10 0.091 0.239 28 2/19/95 17:00 0.203 47 1.08 0.071 0.748 2 2/09/96 3:00 0.197 48 1.05 0.051
0.488 7 1/02/97 9:00 0.194 49 1.03 0.031
0.249 24 10/04/97 15:00 0.174 50 1.01 0.011 Computed Peaks 0.929 100.00 0.990 Computed Peaks 0.758 50.00 0.980 Computed Peaks 0.616 25.00 0.960 Computed Peaks 0.463 10.00 0.900 Computed Peaks 0.437 8.00 0.875 Computed Peaks 0.368 5.00 0.800 Computed Peaks 0.262 2.00 0.500
Computed Peaks 0.214 1.30 0.231
Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.011 288935 65.967 65.967 34.033 0.340E+00 0.032 37852 8.642 74.609 25.391 0.254E+00 0.052 31854 7.273 81.882 18.118 0.181E+00 0.073 27321 6.238 88.119 11.881 0.119E+00 0.094 19673 4.492 92.611 7.389 0.739E-01 0.115 14214 3.245 95.856 4.144 0.414E-01 0.136 9325 2.129 97.985 2.015 0.202E-01 0.157 5302 1.211 99.195 0.805 0.805E-02 0.178 2801 0.639 99.835 0.165 0.165E-02 0.199 122 0.028 99.863 0.137 0.137E-02 0.220 55 0.013 99.875 0.125 0.125E-02 0.241 41 0.009 99.885 0.115 0.115E-02 0.262 27 0.006 99.891 0.109 0.109E-02 0.283 34 0.008 99.899 0.101 0.101E-02 0.304 62 0.014 99.913 0.087 0.872E-03
0.325 72 0.016 99.929 0.071 0.708E-03 0.346 77 0.018 99.947 0.053 0.532E-03 0.366 52 0.012 99.959 0.041 0.413E-03 0.387 62 0.014 99.973 0.027 0.272E-03 0.408 31 0.007 99.980 0.020 0.201E-03
0.429 11 0.003 99.982 0.018 0.176E-03
0.450 9 0.002 99.984 0.016 0.155E-03 0.471 11 0.003 99.987 0.013 0.130E-03 0.492 12 0.003 99.990 0.010 0.103E-03 0.513 18 0.004 99.994 0.006 0.616E-04 0.534 10 0.002 99.996 0.004 0.388E-04 0.555 9 0.002 99.998 0.002 0.183E-04 0.576 3 0.001 99.999 0.001 0.114E-04 0.597 1 0.000 99.999 0.001 0.913E-05 0.618 0 0.000 99.999 0.001 0.913E-05 0.639 1 0.000 99.999 0.001 0.685E-05
0.660 0 0.000 99.999 0.001 0.685E-05 0.680 0 0.000 99.999 0.001 0.685E-05 0.701 0 0.000 99.999 0.001 0.685E-05 0.722 2 0.000 100.000 0.000 0.228E-05 0.743 0 0.000 100.000 0.000 0.228E-05 Flow Duration from Time Series File:dsout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % %
0.011 288697 65.913 65.913 34.087 0.341E+00
0.034 37177 8.488 74.400 25.600 0.256E+00 0.057 32192 7.350 81.750 18.250 0.182E+00 0.079 27178 6.205 87.955 12.045 0.120E+00 0.102 19791 4.518 92.474 7.526 0.753E-01 0.124 14342 3.274 95.748 4.252 0.425E-01 0.147 9422 2.151 97.899 2.101 0.210E-01 0.169 5393 1.231 99.131 0.869 0.869E-02 0.192 2244 0.512 99.643 0.357 0.357E-02
0.214 632 0.144 99.787 0.213 0.213E-02
0.237 244 0.056 99.843 0.157 0.157E-02 0.259 114 0.026 99.869 0.131 0.131E-02 0.282 69 0.016 99.885 0.115 0.115E-02 0.305 76 0.017 99.902 0.098 0.979E-03 0.327 71 0.016 99.918 0.082 0.817E-03 0.350 73 0.017 99.935 0.065 0.651E-03 0.372 68 0.016 99.950 0.050 0.495E-03 0.395 57 0.013 99.963 0.037 0.365E-03 0.417 38 0.009 99.972 0.028 0.279E-03 0.440 23 0.005 99.977 0.023 0.226E-03 0.462 19 0.004 99.982 0.018 0.183E-03 0.485 15 0.003 99.985 0.015 0.148E-03 0.507 12 0.003 99.988 0.012 0.121E-03 0.530 14 0.003 99.991 0.009 0.890E-04 0.553 14 0.003 99.994 0.006 0.571E-04 0.575 10 0.002 99.997 0.003 0.342E-04 0.598 3 0.001 99.997 0.003 0.274E-04 0.620 6 0.001 99.999 0.001 0.137E-04 0.643 1 0.000 99.999 0.001 0.114E-04
0.665 1 0.000 99.999 0.001 0.913E-05 0.688 0 0.000 99.999 0.001 0.913E-05 0.710 1 0.000 99.999 0.001 0.685E-05 0.733 1 0.000 100.000 0.000 0.457E-05 0.756 1 0.000 100.000 0.000 0.228E-05
0.778 0 0.000 100.000 0.000 0.228E-05
0.801 0 0.000 100.000 0.000 0.228E-05 Duration Comparison Anaylsis Base File: predevcombined.tsf New File: dsout.tsf Cutoff Units: Discharge in CFS
-----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.192 | 0.36E-02 0.35E-02 -1.5 | 0.36E-02 0.192 0.192 -0.3
0.234 | 0.21E-02 0.16E-02 -21.8 | 0.21E-02 0.234 0.216 -7.7
0.276 | 0.12E-02 0.12E-02 -4.2 | 0.12E-02 0.276 0.269 -2.4 0.318 | 0.77E-03 0.89E-03 16.4 | 0.77E-03 0.318 0.334 5.2 0.360 | 0.50E-03 0.59E-03 16.8 | 0.50E-03 0.360 0.372 3.4 0.401 | 0.35E-03 0.33E-03 -4.6 | 0.35E-03 0.401 0.398 -1.0 0.443 | 0.23E-03 0.22E-03 -3.0 | 0.23E-03 0.443 0.440 -0.8 0.485 | 0.13E-03 0.15E-03 10.2 | 0.13E-03 0.485 0.497 2.4 0.527 | 0.75E-04 0.91E-04 21.2 | 0.75E-04 0.527 0.540 2.5 0.569 | 0.46E-04 0.41E-04 -10.0 | 0.46E-04 0.569 0.561 -1.4
0.611 | 0.21E-04 0.18E-04 -11.1 | 0.21E-04 0.611 0.609 -0.2
0.653 | 0.11E-04 0.91E-05 -20.0 | 0.11E-04 0.653 0.645 -1.2 0.694 | 0.11E-04 0.68E-05 -40.0 | 0.11E-04 0.694 0.645 -7.2 0.736 | 0.23E-05 0.46E-05 100.0 | 0.23E-05 0.736 0.800 8.7 Maximum positive excursion = 0.072 cfs ( 9.9%) occurring at 0.728 cfs on the Base Data:predevcombined.tsf and at 0.800 cfs on the New Data:dsout.tsf Maximum negative excursion = 0.021 cfs ( -8.5%) occurring at 0.245 cfs on the Base Data:predevcombined.tsf and at 0.224 cfs on the New Data:dsout.tsf
APPENDIX B
Geotechnical Report and Summary Letter
Earth Solutions NW, LLC
APPENDIX C
Critical Area Report for Panther Lake
Sewall Wetland Consulting, Inc.
APPENDIX D
Operation & Maintenance Manual
(Excerpt from Originally Approved Project TIR)
Version WA DOE June 1, 2010
FloGard® Perk Filter Systems
Operations and Maintenance Manual
2 | Page‐ FloGard® Perk Filter System O & M Manual
KriStar Enterprises, Inc.
360 Sutton Place
Santa Rosa, CA 95407
(800) 579‐8819
www.kristar.com
FloGard® Perk Filter Systems- Radial Media Filtration
Description / Basic Function
The Perk Filter is a stormwater filtration device used to reduce pollutant loading in runoff from urban
developments. Impervious surfaces and other urban and suburban landscapes generate a variety of contaminants that can enter stormwater, polluting downstream receiving waters. The Perk Filter captures
and retains sediment, oils, metals and other target constituents close to the source and reduces the total discharge load.
The Perk Filter cartridge is manufactured from durable polymeric components with a
polymer-coated steel support screen and stainless steel hardware. Its base construction allows use with a wide variety of media chosen to address site-specific pollutants of concern.
Perk Filters may be installed as a retrofit to suitable existing curb inlet, drop inlet, or combination catch
basins, as an integral part of a coated steel- or concrete-housed stormwater inlet system for commercial, residential, and industrial developments, or as centralized modular treatment system installed either on-
line or off-line.
Prefiltration
Systems constructed with a catch basin inlet are equipped with a FloGard®Plus Catch Basin Insert for pre-filtration. This insert captures gross pollutants such as trash, debris, hydrocarbons, and large
sediment particles.
Gravity Separation Some Perk Filter systems have an inlet bay wherein the initial stormwater flows are received. This is
separated from the main treatment chamber by a baffle wall with weir assembly. Medium size sediment particles are retained in the inlet bay. A drain down assembly to eliminate standing water from the inlet bay area between storm events is included in standard configurations.
Media Filtration Once the stormwater enters the treatment chamber, it will pass through the filtration cartridges containing the project-specified filter media as the water level rises in the chamber. Very fine pollutant particulates will be retained in the filter cartridges as the water flows through the media to an interior perforated pipe, dropping the treated stormwater into an outlet chamber below a false floor.
Peak Flow Bypass Perk Filter systems are designed with a peak flow bypass to ensure the system will not back up and cause upstream flooding during extraordinary storm events. The bypass weir is an integral part of the baffle wall assembly in the inlet bay and allows peak flow stormwater directly to the outlet chamber.
3 | Page‐ FloGard® Perk Filter System O & M Manual
KriStar Enterprises, Inc.
360 Sutton Place
Santa Rosa, CA 95407
(800) 579‐8819
www.kristar.com
Maintenance Overview for FloGard® Perk Filter Systems State and Local regulations require that stormwater management systems be maintained and serviced
on a recurring basis. The purpose of maintaining a clean and obstruction free Perk Filter system is to ensure the system performs the intended function of the primary design. Trash and debris, floatables,
gross pollutants and sediment can build up in any stormwater system. This can cause the system to function improperly by impeding flow in and out of the system and reducing the operating efficiency of the
media filters. Downstream and upstream, areas could run the risk of flooding and deleterious environmental impact.
Recommended Frequency of Service
It is recommended that FloGard® Perk Filter systems be serviced on a regularly occurring basis. Ultimately the frequency depends on the amount of runoff, pollutant loading, and interference from trash,
debris and gross pollutants as well as proper maintenance of upstream pretreatment devices. However, it is recommended that each installation be inspected in accordance with the following guidelines:
Level 1 Inspection Service – Six (6) months after unit is placed into service, or six (6) months after a
Level 2 or Level 3 inspection.
Level 2 Inspection Service- Four (4) months after a Level 1 inspection. Media filter cartridges shall be
exchanged during this service (10-month intervals).
Service Procedures
Inlet Bay
1. The inlet manhole cover(s) and or grate(s) shall be removed and placed to one side. 2. For systems with a FloGard Plus Catch Basin Insert, the insert will be cleaned in accordance with
the general specifications for maintenance of those devices. After cleaning the filter shall be removed and set aside.
3. Any debris will be removed from the inlet bay(s) and disposed of in accordance with local regulations.
4. Check and clean the area behind and under the inlet weir/bypass assembly. Remove assembly as necessary to conduct inspection.
5. Check drain down assembly and clean if necessary. 6. Re-install catch basin insert filter.
7. Re-install grate or manhole access cover.
Cartridge Bay
1. Remove and place to one side the manhole access covers above the cartridge bay. 2. A Level 1 inspection service shall consist of a visual inspection from the surface level. Observe
and note the condition of the cartridge bay and the cartridges, measure sediment level, if any, and note on maintenance record. Physical entry is not required unless the depth prevents the
entire cartridge bay area from being observed. 3. A Level 2 inspection service shall consist of a physical, confined-space entry into the cartridge bay. The filter cartridges and filter media shall be inspected for condition and filter media life, the sediment level, if any, measured, and any trash or debris removed and disposed of in accordance
with local regulations. All information and recommendations shall be noted on the maintenance record.
4 | Page‐ FloGard® Perk Filter System O & M Manual
KriStar Enterprises, Inc.
360 Sutton Place
Santa Rosa, CA 95407
(800) 579‐8819
www.kristar.com
4. A Level 3 service shall consist of a physical, confined-space entry into the cartridge bay. The filter cartridges shall be removed and replaced with re-charged exchange filter cartridges. As an
option, the filter media may be removed of on-site, the cartridges cleaned, and replacement media be installed into the cartridges. All spent filter media shall be disposed of in accordance
with local regulations. 5. Upon completion of inspection/service, re-install the manhole access cover(s).
6. The manhole cover(s) and/or grate(s) shall be replaced.
Inspection / Maintenance Requirements Listed below are some recommendations for equipment and training for personnel to inspect and
maintain a FloGard® Perk Filter system.
Personnel – OSHA Confined Space Entry Training is a prerequisite for entrance into a system. In the state of California personnel should be CalOSHA certified.
Equipment – Record Taking (pen, paper, voice recorder)
Proper Clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) Flashlight
Tape Measure Measuring Stick
Pry Bar Traffic Control (Flagging, barricades, signage, cones, etc.)
First aid materials Debris and Contaminant collectors
Debris and Contaminant containers Vacuum Truck
Disposal of Gross Pollutants, Hydrocarbons, Sediment, and Filter Media
The collected gross pollutants, hydrocarbons, sediment, and filter media shall be disposed of in accordance with local, state and/or federal agency requirements.