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CITY OF RENTON
PHILIP ARNOLD PARK
Technical Information Report (TIR)
ISSUED FOR PERMIT
Prepared by:
3240 Eastlake Ave E,
Seattle, Washington 98102
206-624-1387 | www.pndengineers.com
PND Project No. 194072
April 2022
04/04/2022
DEVELOPMENT ENGINEERING
JChavez 04/21/2022
PHILIP ARNOLD PARK DRAINAGE REPORT
CITY OF RENTON PND No. 194072
i
TABLE OF CONTENTS
1. PROJECT OVERVIEW .......................................................................................................................................... 1
2. CONDITIONS AND REQUIREMENTS SUMMARY .................................................................................. 2
2.1. Core Requirement #1 – Discharge at the Natural Location ..................................................................... 2
2.2. Core Requirement #2 – Offsite Analysis ..................................................................................................... 2
2.3. Core Requirement #3 – Flow Control.......................................................................................................... 2
2.4. Core Requirement #4 – Conveyance Systems ............................................................................................. 2
2.5. Core Requirement #5 – Erosion and Sediment Control ........................................................................... 2
2.6. Core Requirement #6 – Maintenance and Operations .............................................................................. 3
2.7. Core Requirement #7 – Financial Guarantees and Liability ..................................................................... 3
2.8. Core Requirement #8 – Water Quality ......................................................................................................... 3
2.9. Special Requirement #1 – Other Adopted Area-Specific Requirements ................................................ 4
2.10. Special Requirement #2 – Flood Hazard Area Delineation ...................................................................... 4
2.11. Special Requirement #3 – Flood Protection Facilities ............................................................................... 4
2.12. Special Requirement #4 – Source Control ................................................................................................... 4
2.13. Special Requirement #5 – Oil Control ......................................................................................................... 5
2.14. Special Requirement #6 – Aquifer Protection Areas ................................................................................. 5
3. OFFSITE ANALYSIS ............................................................................................................................................. 5
3.1. Downstream Water Quality Problems Requiring Special Attention ........................................................ 5
3.2. Downstream Water Quality Problems Requiring Special Attention ........................................................ 5
4. FLOW CONTROL, LOW IMPACT DEVELOPMENT (LID) AND WATER QUALITY FACILITY
ANALYSIS AND DESIGN ............................................................................................................................................ 6
4.1. Existing Site Hydrology (Part A).................................................................................................................... 6
4.2. Developed Site Hydrology (Part B) ............................................................................................................... 7
4.3. Performance Standards (Part C)................................................................................................................... 10
4.4. Flow Control System (Part D) ...................................................................................................................... 10
4.5. Water Quality System (Part E) ..................................................................................................................... 11
5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN .............................................................................. 11
6. SPECIAL REPORTS AND STUDIES .............................................................................................................. 11
7. OTHER PERMITS ................................................................................................................................................. 11
8. CSWPP PLAN ANALYSIS AND DESIGN ..................................................................................................... 11
8.1. ESC PLAN ANALYSIS AND DESIGN (PART A) .............................................................................. 12
8.2. SWPPS PLAN DESIGN (PART B) ........................................................................................................... 12
9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ......... 13
10. OPERATIONS AND MANTENANCE MANUAL ................................................................................. 14
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - ii
TABLES
Table 1: Tree Retention Credit Summary ....................................................................................................................... 4
Table 2: Drainage Basin Summary ................................................................................................................................... 8
Table 3: TDA 1 - MGS Flood Peak Discharge Rates ................................................................................................... 8
Table 4: TDA 2 – MGS Flood Peak Discharge Rates .................................................................................................. 9
APPENDICES
Appendix A – TIR Worksheet
Appendix B – Offsite Analysis
Appendix C – Design Drawings
Appendix D – Figures
Figure 1: Vicinity Map
Figure 2: Pre-Developed Basin Map
Figure 3: Post-Developed Basin Map
Figure 4: Soil Map
Figure 5: Flow Control Application Map
Figure 6: Critical Areas Map – Coal Mine Hazard
Figure 7: Critical Areas Map – Regulated Slopes
Appendix E – MGS Flood Model Report
Appendix F – Conveyance Calculations
Appendix G – Geotech Report
Issued for Permit - 1
1. PROJECT OVERVIEW
Philip Arnold Park is an existing park located at 720 Jones Ave S, Renton, WA 98507. The park is located
southeast of the Beacon Way S and Jones Avenue S intersection in southeastern Renton, WA. The park’s
boundary consists of Jones Avenue S to the west, Beacon Way S to the north and East, and Puget Sound
Energy Powerline easements and undeveloped land to the south.
The proposed development includes new paved pedestrian pathways, repaving the existing parking lot, new
park features including gazebos, playground equipment and a public restroom facility. The proposed
development area is approximately 2.7 acres within the 10.71-acre park.
The existing park is mostly covered with maintained landscape grass, brambles, and mature trees. The Park
contains an existing basketball court, playground equipment, baseball/softball field, and restroom building.
There are currently two discharge points from the site, one is to the north at the intersection of Jones Ave S
and Beacon Way S. This system discharges to the Cedar River. The second stormwater discharge point is
located at the intersection of South 9th Street and Jones Ave S. This system discharges to an existing forested
area and ultimately to PUD right-of-way located southwest of the park.
The site contains some steep slopes that have been classified and mapped by the City of Renton meeting the
definition for regulated steep slopes. These slopes are mainly south/southwest of the existing playground
equipment and have been classified medium landslide hazard. The project is also entirely contained within a
Medium Coal Hazard area as characterized by the City of Renton; based on the geotechnical report the
proposed developments do not require mitigation for coal mine hazards.
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 2
2. CONDITIONS AND REQUIREMENTS SUMMARY
This report is provided as a summary of all methods and procedures used for analyzing the drainage areas and
structures for the proposed Philip Arnold Park Project. This report has been generated in accordance with
the City of Renton Surface Water Design Manual (CRSWDM) 2017.
The proposed Philip Arnold Park project results in greater than 2,000 square feet of new plus replaced
impervious surface and greater than 7,000 square feet of land disturbing activity. Per Table 1.1.2.A of the
CRSWDM, the proposed Philip Arnold Park project is subject to a full drainage review.
Projects that are subject to a full drainage review are required to comply with Core Requirements #1 through
#9 and Special Requirements #1 through #6. A summary of the core requirements, and their applicability is
provided below:
2.1. Core Requirement #1 – Discharge at the Natural Location
There are no exemptions to this requirement; therefore, Core Requirement 1 will apply to the project.
Stormwater runoff from the proposed development will discharge to the natural location and not
diverted away from other downstream areas to the extent practical.
2.2. Core Requirement #2 – Offsite Analysis
There are no exemptions to this requirement; therefore, Core Requirement 2 will apply to the project.
2.3. Core Requirement #3 – Flow Control
The project site contains two Threshold Discharge Areas (TDAs). TDA 1, on the northern half of the
project site, discharges to an existing conveyance system that outlets to the Cedar River. This TDA is
exempt from flow control facility requirements as the project meets the Direct Discharge Exemption
requirements in the CRSWDM.
TDA 2, on the southern half of the project site, discharges to an existing conveyance system that outlets
to PUD right-of-way. TDA 2 will be subject to flow control facility requirements per Core Requirement
3. TDA 2 will be required to match the Flow Control Duration Standards for Forested Conditions per
Reference 15-A of the CRSWDM. TDA 2 will achieve this flow control standard through infiltration and
bioretention facilities.
2.4. Core Requirement #4 – Conveyance Systems
A new conveyance system will be constructed as part of the park development. The new conveyance
system for the park will discharge to the existing conveyance system that runs along the eastern side of
Jones Ave South. The Existing conveyance system discharges through an 8” pipe across Beacon Way S,
and north along High Ave S where it discharges to an open channel. The new conveyance system will be
designed to convey the minimum 25-year design storm without overtopping.
2.5. Core Requirement #5 – Erosion and Sediment Control
There are no exemptions to this requirement; therefore, Core Requirement #5 will apply to the project.
Erosion and Sediment Control (ESC) plans will be generated and included in the construction drawings.
The contractor will submit a Construction Stormwater Pollution Prevention Plan (SWPPP).
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 3
2.6. Core Requirement #6 – Maintenance and Operations
There are no exemptions to this requirement; therefore, Core Requirement #6 will apply to the project.
The City will maintain the proposed stormwater conveyance and treatment facilities.
2.7. Core Requirement #7 – Financial Guarantees and Liability
There are no exemptions to this requirement; therefore, Core Requirement #7 will apply to the project.
2.8. Core Requirement #8 – Water Quality
The proposed development will include replacing a portion of the asphalt of the existing parking lot near
Beacon Way South. The proposed repaving will result in more than 5,000 square feet of replaced
pollution-generating impervious surface (PGIS). The infiltration rates and soil properties in the vicinity of
the parking lot meet the requirements of Section 1.2.8 – Exemption 4 Soil Treatment Exemption. Runoff
from the parking lot will be discharged to an infiltration trench, any overflow from the infiltration trench
will be discharged via a flow spreader to a Basic Dispersion/Filter Strip BMP.
The remaining proposed impervious surface for the site consists of concrete pedestrian pathways and
roof runoff. These surfaces will be infiltrated on-site to the extent feasible with infiltration trenches, a
bioretention facility, and french drains. These facilities are not subject to the water quality requirements
as they are not considered pollution generating.
Proposed softscape development includes 1.35 acres of lawn area, shrub ground cover, and engineered
wood fiber playground surface. These areas will be infiltrated to the extent feasible with infiltration
trenches, French drains, and a bioretention facility. These areas are considered replaced pollution-
generating pervious surfaces (PGPS) or in some areas converted hard surface to PGPS, as such these
surfaces are not subject to Core Requirement 8.
Core Requirement #9 – Onsite BMPs
The proposed development will trigger Large Lot BMP Requirements per section 1.2.9.2.2 of the
CRSWDM. Large Lot BMP Requirements require the applicability of the following BMPs be evaluated
for feasibility and implemented to the extent possible.
1) Full Dispersion of all target impervious surfaces – Full dispersion on the site is not feasible as the
existing ground is a developed park. Native forested conditions and/or native predeveloped
vegetation does not exist to disperse and treat stormwater flows. The park largely consists of
maintained lawn and a few trees
2) Full Infiltration of Roof Runoff – City of Renton parks and maintenance department elected to
exclude gutters from the park picnic shelters due to maintenance concerns. Therefore, perforated
downspout connections are not feasible. To the extent feasible, runoff from picnic shelters will
drain to infiltration trenches and french drains and be infiltrated to the extent feasible.
3) Full Infiltration of Target Impervious Surfaces – Target impervious surfaces will be infiltrated to
the extent feasible with infiltration trenches, and french drains. Physical constrains of the site,
including proximity to existing trees and sensitive slopes limit the placement of infiltration
facilities.
4) Limited Infiltration of Target Impervious Surfaces – Where full infiltration is infeasible, limited
infiltration will be applied to the target impervious surfaces.
5) Bioretention – One bioretention facility is proposed for the project. The bioretention facility has
been sized per the site’s physical constraints to collect any runoff from the limited infiltration
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 4
facilities. Bioretention is infeasible in the northern portion of the site due to limited infiltration
rates of the native soil and in areas marked as landslide hazard areas.
6) Permeable Pavement – Permeable pavement is considered infeasible at this site due to the
mapped landslide hazard zones within the park.
7) Basic Dispersion of Target Impervious Surfaces – Basic Dispersion will be implemented to the
extent feasible.
8) Reduction Credits
a. Reduced Impervious Surface Credit – Appendix C, Section C.2.9
The project will not use any Reduced Impervious Surface Credits.
b. Native Growth Retention Credit
The project will not use any Native Growth Retention Credits as the park is already
developed and the existing condition does not contain native groundcover.
c. Tree Retention Credit
The project will use Tree Retention Credits as a vast majority of the trees on site will be
protected and remain. The retention credits for each proposed basin are summarized in
the table below:
Table 1: Tree Retention Credit Summary
Drainage Basin Impervious Surface - Measured (Acres) Tree Retention Credit (Acres)
A 0.75 0.04
B 0.82 0.02
C 0.59 N/A
D 0.6 0.12
9) Moisture Capacity of New Pervious Surfaces (Target Pervious Surfaces) – The soil amendment
BMP detailed in Appendix C of the CRSWDM will be applied.
2.9. Special Requirement #1 – Other Adopted Area-Specific Requirements
The project is not subject to other adopted area-specific requirements.
2.10. Special Requirement #2 – Flood Hazard Area Delineation
The project is not located within a Flood Hazard Area.
2.11. Special Requirement #3 – Flood Protection Facilities
The project does not include or modify any flood protection facilities and is exempt from this
Special Requirements.
2.12. Special Requirement #4 – Source Control
This is a public park development within City-owned property and does not require commercial site
or commercial building permits. The project is exempt from this special requirement.
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 5
2.13. Special Requirement #5 – Oil Control
There are no proposed facilities within this project that meet the requirements for oil control.
2.14. Special Requirement #6 – Aquifer Protection Areas
The project is not located within an Aquifer Protection Area.
3. OFFSITE ANALYSIS
The project is required to address Downstream Drainage problems Requiring Special Attention per Section
1.2.2.1.1, problem Type 4 and Downstream Water Quality Problems Requiring Special Attention (Section
1.2.2.1.2) per Section 1.2.2 of the CRSWDM. The project may be considered exempt from further analysis if
the City of Renton determines there is sufficient information to conclude that the project will not have a
significant adverse impact on the downstream and/or upstream drainage system.
Level 1 Downstream Analysis Summary:
The field report and map of the study area and offsite analysis worksheet are shown in Appendix B. The
study area focused on the two discharge points located at the Cedar River and the PUD property, TDA 1 and
TDA 2 discharge points, respectively.
3.1. DOWNSTREAM WATER QUALITY PROBLEMS REQUIRING SPECIAL
ATTENTION
3.1.1. CONVEYANCE SYSTEM NUISANCE PROBLEM (TYPE 1)
One conveyance system nuisance problem has been noted by the city. The existing catch basin
and pipe connection from the existing parking lot along Beacon Way S. The existing catch basin
has been noted as full of water during multiple site visits suggesting that the downstream pipe is
slow to drain. Public Works suggests this may be the result of tree roots located within the pipe
downstream of the catch basin.
The proposed conveyance system removes the existing conveyance connection and replaces the
parking lot system.
3.1.2. SEVERE EROSION PROBLEM (TYPE 2)
No severe erosion problems have been identified downstream of the project site. The existing
conveyance system discharges to an open channel north of High Ave S. The open channel is located
within an area of High Erosion Hazard per the City of Renton GIS Mapping Service. The proposed
development will match or slightly reduce existing flows to this open channel.
3.1.3. SEVERE FLOODING PROBLEM (TYPE 3)
No severe flooding problems have been identified or are predicted downstream of the project site.
3.1.4. POTENTIAL IMPACTS TO WETLANDS HYDROLOGY (TYPE 4)
There are no mapped wetlands downstream of the project site.
3.2. DOWNSTREAM WATER QUALITY PROBLEMS REQUIRING SPECIAL
ATTENTION
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 6
Runoff from the project site that is not infiltrated is discharged to the existing conveyance system
within Jones Ave. S, Beacon Way, and High Ave S. is discharged to an open channel to the Cedar
River Dog Park. Runoff that exits the open channel discharges to the Cedar River, approximately
2,300-feet downstream from the project site discharge point.
The Cedar River has been classified by the Washington State Department of Ecology Water Quality
Assessment as Category 5 water for the following parameters:
• pH
• Temperature
• Dissolved Oxygen
Category 2 water for the following parameters:
• Mercury
Category 1 water for the following parameters:
• Copper
• Ammonia-N
• Arsenic
• Selenium
• Bacteria
The PGIS parking lot at the Philip Arnold Park is located approximately a half of a mile upstream from the
Cedar River, therefore the requirements of Section 1.2.2.3 of the CRSWDM apply.
4. FLOW CONTROL, LOW IMPACT DEVELOPMENT (LID) AND WATER
QUALITY FACILITY ANALYSIS AND DESIGN
4.1. EXISTING SITE HYDROLOGY (PART A)
Philip Arnold Park is an existing, mostly grass covered, 11.7-Acre site. There are some existing
facilities including a restroom, basketball court, playground equipment and baseball/softball field.
The site generally slopes downward toward the west (Jones Ave S) and site runoff discharges to the
existing conveyance system along Jones Ave S. There are a significant number of large mature trees
spread throughout the park.
There are some classified sensitive slopes within the site, reference Appendix D for the location of
these slopes. The project is generally underlain by glacial till consisting of a mixture of clay, silt,
sand, gravel, cobbles, and boulders. Borings during the geotechnical investigation confirmed the soil
mapping for the project area except for the vicinity immediately west of the parking lot where
outwash sands and gravel were encountered.
The project is within two TDAs, reference Appendix D for the TDA delineation. TDA 1 discharges
to an existing tightline conveyance system within Beacon Ave S. The existing system within Beacon
Ave S connects to the system in High Ave S, which discharges to an open channel north of the
project site. From this discharge point, stormwater flows to the Cedar River.
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 7
TDA 2 discharges to an existing 12-inch diameter tightline conveyance system within Jones Ave S.
this system continues west along S 9th Street where it discharges into a heavily vegetated parcel ID
0007200196 and ultimately to the PUD right of way.
There is an existing 2,000 square foot parking lot located within the boundary of the park off of
Jones Ave S. This parking lot has an existing inlet in the northeast corner that drains to a drywell
located approximately 15 feet east of the parking lot. The proposed development will not modify
this drainage system.
4.2. DEVELOPED SITE HYDROLOGY (PART B)
The developed site conditions include the development of new concrete pathways, resurfacing of an
existing basketball court and a portion of the existing parking lot, new playground equipment area
and surface features, and new landscape. The total areas for the project are summarized in the table
below.
Under the proposed conditions, Drainage Basin A will generally collect runoff from the parking lot
and baseball field hardscape area. Stormwater will be collected and conveyed by a new tightline
system in the parking lot. Stormwater from this system will be discharged to an infiltration trench at
the northwest side of the parking lot. Additional flows that cannot be infiltrated will be dispersed by
a spreader board where they will be discharged to the existing park area. The dispersion of these
flows will provide some additional treatment and infiltration. Stormwater that is not infiltrated will
be collected by the french drain and catch basin located at the northern corner of the project and
discharged to the tightline system within Beacon Ave S.
Surface water runoff from Drainage Basin B will generally sheet flow to the north west and be
collected by the proposed French drains and catch basins along the eastern edge of the new
pathway. Runoff collected by these French drains and catch basins will discharge to the existing
system within Beacon Ave S.
Drainage Basin C consists of limited new park improvements. Improvements within this basin
generally include grading for the new park pathway and a small portion of new ADA ramps. Runoff
from drainage basin C will sheet flow to the curb along Jones Ave S where it is collected by the
existing tightline conveyance system and discharges to Beacon Way S.
Drainage Basin D also consists of limited new park improvements. These improvements generally
include a portion of new concrete pathway and elevated boardwalk, grading for the new pathway,
and new landscape/sod planting. Surface water runoff from this drainage basin will discharge to a
natural depression between the Jones Ave S roadway and the new park development before
discharging to the existing tightline conveyance system within Jones Ave S.
Surface runoff from Drainage Basin D generally flows from east to west. Runoff from this basin
will be intercepted along the perimeter of the new pedestrian path and underneath the new play area
and infiltrated using infiltration trenches and French drains. Roof runoff from the two proposed
gazebos within this drainage basin will drain to infiltration trenches and french drains and be
infiltrated to the extent feasible. Any runoff that is not infiltrated by the infiltration trenches or
French drains will be discharged via a new tightline conveyance system to a new bioretention facility
located immediately east of the intersection of Jones Ave S and S 9th Ave.
Table 2 below summarizes the post-developed TDAs and drainage basin areas. Existing and
proposed pervious and impervious surfaces are summarized below as measured on-site. No BMP
reduction credits are included in these values.
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 8
Table 2: Drainage Basin Summary
Web Soil Survey classifies the underlaying soil as AMc – Arents, Alderwood Material with a
Hydrologic Soil Rating of B/D. The site geotechnical investigation encountered outwash sands and
gravels throughout most of the site, therefore Outwash Grass was used as the modeling parameter
for the existing and proposed landscape condition for the site at it most closely matches with the
hydrologic soil group and the findings of the geotechnical report. The proposed impervious surfaces
(e.g. new concrete pathways, roofs, parking lot, etc.) were modeled as impervious surface.
Tables 3 and 4 below shows the stormwater peak runoff rates based on the impervious and pervious
surface areas within each drainage basin. Runoff rates were calculated using MGS Flood 5-Minute
Timesteps. The infiltration, dispersion, and bioretention facilities were modeled within MGS Flood.
To calculate the pre-development Forested Condition for TDA 2, Outwash Forest was used as the
MGS flood modeling parameter for the entire TDA.
Table 3: TDA 1 - MGS Flood Peak Discharge Rates
TDA Basin Existing Pervious
(Acre)
Existing Impervious
(Acre)
Proposed Pervious
(Acre)
Proposed
Impervious (Acre)
1 A 0.50 0.57 0.49 0.74
1 B 2.20 0.12 1.64 0.56
2 C 0.41 0 0.37 0.06
2 D 2.863 0.09 2.50 0.19
Storm Event
Existing Peak
Flow Rates
(cfs)
Proposed Peak Flow
Rates (cfs)
2-Year 0.267 0.114
10-Year 0.433 0.239
25-Year 0.547 0.310
50-Year 0.721 0.401
100-Year 0.760 0.467
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 9
Table 4: TDA 2 – MGS Flood Peak Discharge Rates
4.2.1. PARKING LOT DRAINAGE BMPS:
A new conveyance and treatment system will be installed for the parking lot adjacent to Beacon
Ave. The existing parking lot has no treatment system currently; stormwater is collected via
catch basins in the parking lot and piped to the conveyance system in Beacon Ave.
A new conveyance system will be constructed, roughly in the middle of the drive lanes of the
parking lot, and convey water to an infiltration trench at the northwest end of the parking lot.
The soils in this area have a cation exchange capacity meeting the groundwater protection
requirements of the City of Renton SWDM, soil properties, and depth to groundwater to
infiltrate runoff for treatment. Due to the parking lots proximity to existing trees that are to
remain, the infiltration trench will treat the runoff from the parking lot. Any additional flows
from the parking lot that overtop the infiltration trench will be dispersed via a level spreader
travel through a filter strip BMP.
4.2.2. CONCRETE PATHWAY BMPS:
Runoff from the proposed concrete pathways will sheet flow off the surface and into the
adjacent landscaping. Infiltration trenches are provided on the southern side of the project
where infiltration has been determined to be feasible. Along the northern corner of the site,
French drains are provided in areas where infiltration is infeasible. Runoff will be collected by
these BMPs and infiltrated to the extent feasible. Excess runoff from the French drains and
infiltration trenches will be conveyed to a bioretention facility that has been sized per the
geometric constraints of the site. Excess runoff from the bioretention facility will be
discharged to the existing drainage system along Jones Ave. S.
The concrete pathway on the northern portion of site will sheet flow off the path surface and
use the proposed and existing park lawn landscape for basic dispersion.
4.2.3. ROOF RUNOFF
Runoff from the two-gazebo roofs and the Portland Loo will sheet flow across the adjacent
pavement, where it will be collected by french drains or infiltration trenches. Roof runoff will
be infiltrated to the extent feasible.
Storm Event
Forested
Condition
Flow Rates
(cfs)
Proposed Peak Flow
Rates (cfs)
2-Year 3.647E-03 0.000
10-Year 4.913E-03 0.000
25-Year 5.586E-03 8.142E-04
50-Year 5.918E-03 1.154E-03
100-Year 6.102E-03 2.015E-03
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 10
4.3. PERFORMANCE STANDARDS (PART C)
4.3.1. FLOW CONTROL STANDARDS
TDA 1 is exempt from flow control standards as it meets the Direct Discharge Exemption in
Section 1.2.3.1 of the CRSWDM.
TDA 2 is required to meet flow control standards. The project site is within an area requiring
runoff leaving the site to match forested conditions. TDA 2 achieves this standard through
infiltration and bioretention BMPs.
4.3.2. CONVEYANCE SYSTEM CAPACITY STANDARDS
The proposed tightline conveyance system in the parking lot adjacent to Beacon Way S will be
constructed to convey the 25-year storm event without overtopping any inlet. The conveyance
capacity analysis is shown in Appendix F.
The proposed open channel grass ditch along Jones Ave S regrades the existing grass ditch.
The ditch was analyzed to confirm it can convey the 100-year event without overtopping. The
capacity analysis is shown in Appendix F.
The proposed tightline conveyance systems within Philip Arnold Park serve to connect and
convey runoff to/and from infiltration facilities. The purpose of these infiltration facilities is to
attenuate and infiltrate stormwater runoff; therefore, the rational method and calculation of
peak runoff rates to calculate pipe sizes and slopes will be overly conservative. Through
analysis of the MGS Flood predicted flow rates, after runoff has been infiltrated and treated by
the proposed BMPs, the minimum pipe sizes required by the City of Renton SWDM is 12”
diameter with a minimum of 0.5% slope. 12” Diameter pipes will have sufficient capacity to
convey the proposed runoff.
4.4. FLOW CONTROL SYSTEM (PART D)
Flow control on site will be provided through infiltration trenches, french drains, bioretention
facilities, and natural depressions. These facilities are shown in Appendix C.
Supporting documentation for these facilities are shown in the MGS flood model printouts shown
in Appendix E.
Design infiltration rates are calculated and presented in the Geotechnical Engineering Report prepared by
ZipperGeo. The northern corner of the project site, around infiltration test 1 (IT-1) was measured
to be 0.0625. This area is infeasible for infiltration. French Drains will be used in the vicinity of IT-1
to capture surface runoff and infiltrate to the extent feasible.
The measured infiltration rates at IT-2 and IT-3 were measured to be 21.4 inches per hour and 1.24
inches per hour, respectively. The recommended design infiltration rate, based on the recommended
equation in the CRSDWM for IT-2 and IT-3 is 8 inches per hour and 0.5 inches per hour,
respectively. Infiltration trenches will be installed in the vicinity of IT-2 and IT-3. Reference Figure
1 in the Geotechnical Engineering Report for infiltration test locations.
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 11
4.5. WATER QUALITY SYSTEM (PART E)
The only proposed water quality system for this project is located at the northwest side of the
parking lot along Beacon Ave S. This system consists of a dispersion trench and a filter strip which
will infiltrate runoff collected by the conveyance system in the parking lot. The infiltration facility is
capable of infiltrating and filtering 96.20% of runoff contributed. The remaining runoff will be
discharged via a flow spreader to a basic dispersion BMP northwest of the parking lot. Water
Quality Statistics from MGS flood are shown in Appendix E.
5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Calculations for the conveyance systems discussed in section 4.3.2 are shown in Appendix F.
6. SPECIAL REPORTS AND STUDIES
The Geotechnical Engineering Report prepared by ZipperGeo notes that the project is located within a coal mine
hazard zone and there are some sensitive slopes within the park boundary. In the opinion of the geotechnical
assessment, the proposed development can be safely accommodated on site with no adverse impact to these
critical areas. There are Temporary Erosion and Sediment Control (ESC) plans that will be included in the
construction set. The contractor will be required to prepare a project Stormwater Pollution Prevention Plan
(SWPPP)
The Geotechnical Engineering Report evaluated the potential for infiltration facilities in three locations, reference
Figure 1 in the Geotechnical Engineering Report. Measured and design infiltration rates are presented in the
Stormwater Infiltration Considerations section of this report.
Section 5.2.1 of the City of Renton SWDM details the requirements for groundwater mounding analysis. The
proposed infiltration facilities will have a minimum of 5-feet of separation between the bottom of the facility
and the measured water table and no single infiltration facility will have a contributing area greater than one
acre. Therefore, the project is exempt from performing a groundwater mounding analysis.
7. OTHER PERMITS
The following permits are anticipated for the project:
• General Construction Stormwater Permit and Notice of Intent – Washington Department of
Ecology
• Civil Construction Permit – City of Renton
o Grading and Clearing Permit
8. CSWPP PLAN ANALYSIS AND DESIGN
The final contract documents will include ESC plans in accordance with the City of CRSWDM. ESC
plans are shown in Appendix C.
The project will follow the requirements of the National Pollutant Discharge Elimination System
(SPDES) General Construction Stormwater Permit. The contractor will develop a SWPPP per all local
guidelines.
During construction, stormwater runoff will be conveyed to the existing conveyance systems. ESC
measures will be implemented to prevent erosion and sediment discharging to these systems. The
Contractor will be responsible for construction phasing and stabilizing slopes during construction,
especially during clearing and grading activities.
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 12
8.1. ESC PLAN ANALYSIS AND DESIGN (PART A)
The proposed ESC plan includes the implementation of the following BMPs:
• Preserve Natural Vegetation – The contractor shall preserve the natural vegetation to the extent
possible. Limits of clearing and grading shall be clearly noted by flags or other methods.
• Ground Cover – The contractor shall place ground cover (mulch, vegetation, etc.) on sloped areas if
vegetation has been removed and there is potential for erosion.
• Plastic Sheeting – The contractor shall cover soil stockpiles and open trenches with plastic sheeting.
• Straw Mulch Cover – The contractor shall place straw mulch cover in areas where existing vegetation
has been removed and there is potential for erosion.
• Dust Control – The contractor shall implement dust control measures (i.e. street sweeping, watering
exposed soils, etc.) throughout construction as necessary.
• Temporary & Permanent Seeding – If the construction schedule dictates that vegetated groundcover
will be removed for an extended period, temporary seeding will be considered to reduce the potential
for erosion.
• Sediment Fence (Interior) – Sediment fences will be placed as shown on the plans, if the contractor
or engineer deems necessary during construction activities, additional silt fence shall be placed for
facilitate construction phasing.
• Inlet Protection – Inlet sediment traps shall be placed in all nearby inlets throughout construction.
• Construction Entrance – A construction entrance shall be constructed and used until final paving
activities. The contractor shall be responsible for maintaining and repairing the entrance as necessary.
Should any track out occur, the contractor shall clean the affected areas.
• Surface Roughening – The contractor shall roughen the surface of exposed slopes to prevent
erosion.
• Check Dams – Check dams will be constructed in the open channel ditch along Jones Ave S, per the
requirements of DOE BMP C207.
• Proper Signage – The contractor shall maintain signs to protect existing trees to remain, and mark
the limits of clearing and grading. The construction site will be bound by a construction fence
throughout construction.
• Haz Waste Management – The contractor shall implement Hazardous Waste Management during the
asbestos and lead abatement of the existing building.
• Spill Kit On-Site – The contractor shall keep a spill kit on site throughout construction.
• Concrete Washout Area – The contractor shall either construct and maintain a concrete washout area
on-site or dictate that concrete washout is to occur offsite.
8.2. SWPPS PLAN DESIGN (PART B)
The proposed SWPPS Plan includes the implementation of the following BMPs in accordance with
five principles listed below:
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 13
• Follow effective pollutant handling and disposal procedures. All pollutants that occur
onsite shall be handled and disposed in a manner that does not cause stormwater
contamination.
o BMP: Concrete Washout Area (SWDM Section D.2.2.2)
o BMP: Sawcutting and Surfacing Pollution Prevention (SWDM Section D.2.2.3)
o BMP: Maintain Protective BMPs (SWDM Section D.2.2.10)
• Provide cover and containment for materials, fuel and other pollutants. All chemicals,
liquid products, petroleum products, and non-inert wastes present on the site shall be
covered, contained, and protected from vandalism.
o BMP: Material Delivery, Storage, and Containment (SWDM Section D.2.2.4)
• Manage the project site to maximize pollutant control and minimize pollutant
sources. Onsite parking for construction equipment and contractor vehicles shall be
limited to a designated and controllable area. Construction and maintenance operations
shall be scheduled to avoid exposing pollutant sources to inclement weather. Drip Pans will
be provided for any fueling operations.
o BMP: Manage the Project (SWDM Section D.2.2.11)
• Protect from spills and drips of petroleum products and other pollutants.
Maintenance and repair of heavy equipment and vehicles shall be limited to minor
maintenance and fueling as much as possible. Spill prevention measures, such as drip pans
and temporary plastic sheets, shall be provided when conducting maintenance.
Contaminated surfaces shall be cleaned immediately following any discharge or spill
incident.
• Avoid overapplication or untimely application of chemicals and fertilizers.
Agricultural chemicals, including fertilizers and pesticides, shall be applied in a manner and
at application rates that will not result in loss of chemical to stormwater runoff.
• Prevent or treat contamination of stormwater runoff by pH modifying sources.
These sources include, but are not limited to, bulk cement, cement kiln dust, fly ash, new
concrete washing and curing waters, waste streams generated from concrete grinding and
sawing, exposed aggregate processes, and concrete pumping and mixer washout waters.
Stormwater discharges shall not cause or contribute to a violation of the water quality
standard for pH in the receiving water.
o BMP: Concrete Handling (SWDM Section D.2.2.1)
o BMP: PH Control for High PH Water Prevention (SWDM Section D.2.2.8)
9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF
COVENANT
Per the City of Renton SWDM, a Flow Control and Water Quality Facility Summary Sheet and Sketch shall
be submitted aver approval of the plans.
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 14
10. OPERATIONS AND MANTENANCE MANUAL
An operations and maintenance manual is not provided. This is a City of Renton project, and the city will
assume the operations and maintenance of all stormwater systems.
PHILIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 15
References:
City of Renton. 2016. Surface Water Design Manual (CRSWDM).
https://rentonwa.gov/UserFiles/Servers/Server_7922657/File/City%20Hall/Public%20Works/Utility%20S
ystems/Surface%20Water%20Design%20Standards/2017RentonSWDM_Complete_Final_Final.pdf. City of
Renton, Public Works Department, Washington. May.
City of Renton COR MAPS. (MAPS). 2021. City of Renton GIS Map,
https://maps.rentonwa.gov/Html5viewer/Index.html?viewer=cormaps. May.
United States Department of Agriculture (USDA). 2021. Soil Survey, Natural Resources Conservation Service, Web
Soil Survey. https://websoilsurvey.sc.egov.usda.gov/. May.
ZipperGeo. Geotechnical Engineering Report Philip Arnold Park Improvements. October 27, 2020. Prepared by
ZipperGeo Geoprofessional Consultants.
PHILLIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 15
Appendix A – TIR Worksheet
CITY OF RENTON SURFACE WATER DESIGN MANUAL
2017 City of Renton Surface Water Design Manual 12/12/2016 8-A-1
REFERENCE 8-A
TECHNICAL INFORMATION REPORT (TIR)
WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER Part 2 PROJECT LOCATION AND
DESCRIPTION
Project Owner _____________________________
Phone ___________________________________
Address __________________________________
_________________________________________
Project Engineer ___________________________
Company _________________________________
Phone ___________________________________
Project Name __________________________
CED Permit # ________________________
Location Township ________________
Range __________________
Section _________________
Site Address __________________________
_____________________________________
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
Land Use (e.g., Subdivision / Short Subd.)
Building (e.g., M/F / Commercial / SFR)
Grading
Right-of-Way Use
Other _______________________
DFW HPA
COE 404
DOE Dam Safety
FEMA Floodplain
COE Wetlands
Other ________
Shoreline
Management
Structural
Rockery/Vault/_____
ESA Section 7
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review
(check one):
Date (include revision
dates):
Date of Final:
Full
Targeted
Simplified
Large Project
Directed
__________________
__________________
__________________
Plan Type (check
one):
Date (include revision
dates):
Date of Final:
Full
Modified
Simplified
__________________
__________________
__________________
City of Renton
(425) 430-6400
1055 S. Grady Way,
Renton, WA 98057
Chase Castona
PND Engineers
624-1387
Phillip Arnold Park
720 Jones Ave S
Renton, WA 98057
23N
5E
20
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-2
Part 6 SWDM ADJUSTMENT APPROVALS
Type (circle one): Standard / Blanket
Description: (include conditions in TIR Section 2)
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
Approved Adjustment No. ______________________ Date of Approval: _______________________
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes / No
Start Date: _______________________
Completion Date: _______________________
Describe: _________________________________
_________________________________________
_________________________________________
Re: SWDM Adjustment No. ________________
Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan: ____________________________________________________________________
Special District Overlays: ______________________________________________________________
Drainage Basin: _____________________________________________________________________
Stormwater Requirements: _____________________________________________________________
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
River/Stream ________________________
Lake ______________________________
Wetlands ____________________________
Closed Depression ____________________
Floodplain ___________________________
Other _______________________________
_______________________________
Steep Slope __________________________
Erosion Hazard _______________________
Landslide Hazard ______________________
Coal Mine Hazard ______________________
Seismic Hazard _______________________
Habitat Protection ______________________
_____________________________________
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3
Part 10 SOILS
Soil Type
______________________
______________________
______________________
______________________
Slopes
________________________
________________________
________________________
________________________
Erosion Potential
_________________________
_________________________
_________________________
_________________________
High Groundwater Table (within 5 feet)
Other ________________________________
Sole Source Aquifer
Seeps/Springs
Additional Sheets Attached
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE
Core 2 – Offsite Analysis_________________
Sensitive/Critical Areas__________________
SEPA________________________________
LID Infeasibility________________________
Other________________________________
_____________________________________
LIMITATION / SITE CONSTRAINT
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Threshold Discharge Area:
(name or description)
Core Requirements (all 8 apply):
Discharge at Natural Location Number of Natural Discharge Locations:
Offsite Analysis Level: 1 / 2 / 3 dated:__________________
Flow Control (include facility
summary sheet)
Standard: _______________________________
or Exemption Number: ____________
On-site BMPs: _______________________________
Conveyance System Spill containment located at: _____________________________
Erosion and Sediment Control /
Construction Stormwater Pollution
Prevention
CSWPP/CESCL/ESC Site Supervisor: _____________________
Contact Phone: _________________________
After Hours Phone: _________________________
SEE ATTACHED GEOTECHNICAL REPORT
STEEP SLOPES/LANDSLIDE HAZARD/COAL MINE HAZARD
INFILTRATION IS INFEASIBLE IN THE NORTH CORNER OF THE PARK
SEE ATTACHED GEOTECHNICAL REPORT
TDA 1
1
DISPERSION TRENCH, FILTER STRIP, FRENCH DRAINS
6/1/2021
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Maintenance and Operation Responsibility (circle one): Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and Liability Provided: Yes / No
Water Quality (include facility
summary sheet)
Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog
or Exemption No. _______________________
Special Requirements (as applicable):
Area Specific Drainage
Requirements
Type: SDO / MDP / BP / Shared Fac. / None
Name: ________________________
Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None
100-year Base Flood Elevation (or range): _______________
Datum:
Flood Protection Facilities Describe:
Source Control
(commercial / industrial land use)
Describe land use:
Describe any structural controls:
Oil Control High-Use Site: Yes / No
Treatment BMP: _________________________________
Maintenance Agreement: Yes / No
with whom? _____________________________________
Other Drainage Structures
Describe:
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3
Part 10 SOILS
Soil Type
______________________
______________________
______________________
______________________
Slopes
________________________
________________________
________________________
________________________
Erosion Potential
_________________________
_________________________
_________________________
_________________________
High Groundwater Table (within 5 feet)
Other ________________________________
Sole Source Aquifer
Seeps/Springs
Additional Sheets Attached
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE
Core 2 – Offsite Analysis_________________
Sensitive/Critical Areas__________________
SEPA________________________________
LID Infeasibility________________________
Other________________________________
_____________________________________
LIMITATION / SITE CONSTRAINT
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Threshold Discharge Area:
(name or description)
Core Requirements (all 8 apply):
Discharge at Natural Location Number of Natural Discharge Locations:
Offsite Analysis Level: 1 / 2 / 3 dated:__________________
Flow Control (include facility
summary sheet)
Standard: _______________________________
or Exemption Number: ____________
On-site BMPs: _______________________________
Conveyance System Spill containment located at: _____________________________
Erosion and Sediment Control /
Construction Stormwater Pollution
Prevention
CSWPP/CESCL/ESC Site Supervisor: _____________________
Contact Phone: _________________________
After Hours Phone: _________________________
SEE ATTACHED GEOTECHNICAL REPORT
TDA 2
1
6/1/2021
DISPERSION TRENCH, FILTER STRIP, INFILTRATION TRENCHES
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Maintenance and Operation Responsibility (circle one): Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and Liability Provided: Yes / No
Water Quality (include facility
summary sheet)
Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog
or Exemption No. _______________________
Special Requirements (as applicable):
Area Specific Drainage
Requirements
Type: SDO / MDP / BP / Shared Fac. / None
Name: ________________________
Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None
100-year Base Flood Elevation (or range): _______________
Datum:
Flood Protection Facilities Describe:
Source Control
(commercial / industrial land use)
Describe land use:
Describe any structural controls:
Oil Control High-Use Site: Yes / No
Treatment BMP: _________________________________
Maintenance Agreement: Yes / No
with whom? _____________________________________
Other Drainage Structures
Describe:
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-5
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
Clearing Limits
Cover Measures
Perimeter Protection
Traffic Area Stabilization
Sediment Retention
Surface Water Collection
Dewatering Control
Dust Control
Flow Control
Control Pollutants
Protect Existing and Proposed
BMPs/Facilities
Maintain Protective BMPs / Manage
Project
MINIMUM ESC REQUIREMENTS
AFTER CONSTRUCTION
Stabilize exposed surfaces
Remove and restore Temporary ESC Facilities
Clean and remove all silt and debris, ensure
operation of Permanent BMPs/Facilities, restore
operation of BMPs/Facilities as necessary
Flag limits of sensitive areas and open space
preservation areas
Other _______________________
Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch)
Flow Control Type/Description Water Quality Type/Description
Detention
Infiltration
Regional Facility
Shared Facility
On-site BMPs
Other
________________
________________
________________
________________
________________
________________
Vegetated Flowpath
Wetpool
Filtration
Oil Control
Spill Control
On-site BMPs
Other
________________
________________
________________
________________
________________
________________
________________
Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS
Drainage Easement
Covenant
Native Growth Protection Covenant
Tract
Other ____________________________
Cast in Place Vault
Retaining Wall
Rockery > 4′ High
Structural on Steep Slope
Other _______________________________
(1)
(2)
(3)
(1) French Drains, Dispersion Trench, Bio-retention, Infiltration Trenches, Filter Strip
(2) Inlet Sediment Traps, Construction Entrance, Silt Fence, Check Dams.
(3) Filter Strip, Dispersion Trench.
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-6
Part 17 SIGNATURE OF PROFESSIONAL ENGINEER
I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were
incorporated into this worksheet and the attached Technical Information Report. To the best of my
knowledge the information provided here is accurate.
____________________________________________________________________________________ Signed/Date
PHILLIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 16
Appendix B – Off-site Analysis
9,028 752
Offsite Analysis Study Area
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
None
10/12/2021
Legend
5120256
THIS MAP IS NOT TO BE USED FOR NAVIGATION
Feet
Notes
512
WGS_1984_Web_Mercator_Auxiliary_Sphere
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Pump Station
Discharge Point
Surface Water Main
Culvert
Open Drains
Facility Outline
Private Pump Station
Private Discharge Point
Private Pipe
Private Culvert
Private Open Drains
Private Facility Outline
Stormwater Ponds
Facility Transfer
Streets
Parks
Waterbodies
OFSITE ANALYSIS STUDY
AREA
AREA UNACCESIBLE,
HEAVILY VEGETATED
AND STEEP SLOPES
TDA 1 DISCHARGE
POINT
TDA 2 DISCHARGE
POINT
1736 4th AVENUE SOUTH, SUITE A, SEATTLE, WASHINGTON 98134 | phone: 206.624.1387 | fax: 206.624.1388
OFFSITE ANALYSIS REPORT
OBSERVER Chase Castona, PE DATE 10/25/21
Project: Phillip Arnold Park Report No: 001
File No: 194072 Date: June 1, 2021,
Client: City of Renton Day of the Week: Tuesday
WEATHER TEMP WIND HUMIDITY
Sunny 80 F Moderate High
FIELD ACTIVITIES
Arrived onsite at 10:45 AM to perform the offsite analysis. The purpose of this site visit was to confirm the existing drainage patterns,
existing conveyance systems, discharge locations and view the downstream conveyance systems.
The park contains two Threshold Discharge Areas (TDAs). Generally, TDA 1 is located on the northern portion of the site, including the
existing parking lot along Beacon Way S, the drainage around the baseball field and the northern corner of the park. Jones Ave S, from the
intersection with S 9th Street to S 7th Street sheet flows into an existing grass ditch along the northern border of the Park. TDA 1 discharges
through an existing tightline conveyance system in Beacon Way S, through High Ave S and into a forested area between High Ave S and the
Cedar River Dog Park. Surface water runoff at the Cedar River Dog Park is collected and conveyed to an existing 12-inch diameter outfall on
the Cedar River.
TDA 2 is generally located on the southern portion of the site. TDA 2 discharges to an existing system in Jones Ave which eventually
discharges to surface water flow at Renton Ave S into PUD property.
No conveyance nuisances, severe erosion, severe flooding, or potential impacts to wetlands were noted during the site visit.
Phillip Arnold Park PND 194072
Offsite Analysis Report No. 001
Page 2 of 6
Photograph No. 1
Description:
TDA 1:
Existing catch basin in the parking lot along
Beacon Way S. The catch basin was full of
water at the time of the site visit; inlet or outlet
pipes could not be viewed.
Per correspondence with the City of Renton,
there is a 6” outlet pipe from this structure that
connected to an existing 12” pipe that runs
parallel to Beacon Way S. The 6” pipe is root
bound. See Photograph 2 for a markup of this
pipe layout.
Photograph No. 2
Description:
TDA 1:
Schematic Provided by the City showing the
approximate locations of the existing 6” and 12”
pipe downstream of the catch basin shown in
photograph 1.
Photograph No. 3
Description:
TDA 1:
Existing catch basin along Jones Ave
photographed. Structure sump full of organic
material (leaves & grass clippings). Pipes appear
to be consistent with the survey.
Location:
N: 175806.95
E: 13003272.25
Phillip Arnold Park PND 194072
Offsite Analysis Report No. 001
Page 3 of 6
Photograph No. 3
Description:
TDA 1:
Existing catch basin along Jones Ave
photographed. Structure sump was full of water
and organic material. Pipes appear to be
consistent with the survey.
Location:
N: 175658.00
E: 1303270.25
Photograph No. 4
Description:
TDA 1:
Grass drainage ditch along Jones Ave S
photographed; view facing south. The eastern
drive lane of Jones Ave S drains to this ditch.
Photograph No. 5
Description:
TDA 1:
Grass drainage ditch along Jones Ave S
photographed; view facing north. The eastern
drive lane of Jones Ave S drains to this ditch.
Phillip Arnold Park PND 194072
Offsite Analysis Report No. 001
Page 4 of 6
Photograph No. 6
Description:
TDA 1:
Existing grass drainage from the basketball court.
Stormwater sheetflows towards Jones Ave.
Photograph No. 8
Description:
TDA 1:
Sloped grass area forming a depression north of
the parking lot along Jones Ave S.
Photograph No. 9
Description:
TDA 1:
Existing area drain located in the grass area
located approximately 90 feet north of the parking
lot along Jones Ave. Appears to be consistent
with the survey. No pipes were visible.
Phillip Arnold Park PND 194072
Offsite Analysis Report No. 001
Page 5 of 6
Photograph No. 10
Description:
Inlet located in the northeast corner of the
existing parking lot along Jones Ave S. The inlet
was full of organic material and had a PVC pipe
outlet. Per correspondence with the city
maintenance staff, the pvc drain extends
approximately 15- due east where it connects to
an 18x18-inch bottomless box. The proposed
development is not modifying the drainage
characteristics of this parking lot – no
modifications are planned for this drainage
system.
Photograph No. 11
Description:
TDA 1:
Existing catch basin near the baseball field
backstop. Pipes could not be viewed to confirm a
connection point to an adjacent stormwater
conveyance system. It is assumed the catch basins
around the backstop drain to the conveyance
system in the parking lot along Beacon Way S.
Photograph No. 12
Description:
TDA 1:
Existing building and north half of the parking lot
along Beacon Way S pictured. The existing park
bathroom does not have a gutter system –
stormwater sheet flows from the roof onto the
surrounding grass.
Phillip Arnold Park PND 194072
Offsite Analysis Report No. 001
Page 6 of 6
Photograph No. 13
Description:
TDA 2:
Discharge point for TDA 2, located on Renton
Ave S between the intersection of S 9th Street
Renton Ave S. Per the City of Renton GIS maps
the existing system discharges to surface flow
through the heavily vegetated area where it
eventually discharges. The vegetation and slopes
were too steep to access the area on foot.
Photograph No. 14
Description:
TDA 1:
COR GIS Facility ID No. 450542 Ditch
photographed near the cedar river dog park
located approximately 0.35 Miles downstream of
the northernmost corner of Phillip Arnold Park.
The drainage from this area sheet flows into catch
basins located in the Cedar River Dog Park and
discharges through an outfall to the Cedar River.
Access upstream from this point was limited due
to thick vegetation and steep slopes.
Photograph No. 15
Description:
TDA 1:
Approximate location of COR GIS Facility ID
No. OUT-0600. Due to the steep slopes and
vegetation the outfall was not accessible.
PHILLIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 17
Appendix C – Design Drawings
PHILLIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 18
Appendix D – Figures
Hydrologic Soil Group—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/26/2021
Page 1 of 4525776052578105257860525791052579605258010525806052581105258160525776052578105257860525791052579605258010525806052581105258160560500560550560600560650560700560750560800
560500 560550 560600 560650 560700 560750 560800
47° 28' 27'' N 122° 11' 50'' W47° 28' 27'' N122° 11' 34'' W47° 28' 12'' N
122° 11' 50'' W47° 28' 12'' N
122° 11' 34'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84
0 100 200 400 600
Feet
0 30 60 120 180
Meters
Map Scale: 1:2,130 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: King County Area, Washington
Survey Area Data: Version 16, Jun 4, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 25, 2020—Jul 27,
2020
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Hydrologic Soil Group—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/26/2021
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
AgC Alderwood gravelly
sandy loam, 8 to 15
percent slopes
B 0.0 0.1%
AmC Arents, Alderwood
material, 6 to 15
percent slopes
B/D 11.0 99.9%
Totals for Area of Interest 11.1 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Hydrologic Soil Group—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/26/2021
Page 3 of 4
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/26/2021
Page 4 of 4
LakeDesire
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PantherLake LakeYoungs
LakeWashington
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,§-405
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Flow Control Application Map
Reference 15-A
Date: 01/09/2014
Flow Control Standards
Peak Rate Flow Control Standard (Existing Site Conditions)
Flow Control Duration Standard (Existing Site Conditions)
Flow Control Duration Standard (Forested Conditions)
Flood Problem Flow
Unincorporated King County Flow Control Standards
Renton City Limits
Potential Annexation Area
4,514 376
Critical Areas Map - Coal Mine Hazard
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
None
5/20/2021
Legend
2560128
THIS MAP IS NOT TO BE USED FOR NAVIGATION
Feet
Notes
256
WGS_1984_Web_Mercator_Auxiliary_Sphere
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Coalmines
High
Moderate
Unclassified
Environment Designations
Natural
Shoreline High Intensity
Shoreline Isolated High Intensity
Shoreline Residential
Urban Conservancy
Jurisdictions
Streams (Classified)
<all other values>
Type S Shoreline
Type F Fish
Type Np Non-Fish
Type Ns Non-Fish Seasonal
Unclassified
Not Visited
Wetlands
Streets
Points of Interest
Parks
Waterbodies
2019.sid
Red: Band_1
4,514 376
Critical Areas Map - Regulated Slopes
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
None
5/20/2021
Legend
2560128
THIS MAP IS NOT TO BE USED FOR NAVIGATION
Feet
Notes
256
WGS_1984_Web_Mercator_Auxiliary_Sphere
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Slope City of Renton
>15% & <=25%
>25% & <=40% (Sensitive)
>40% & <=90% (Protected)
>90% (Protected)
Slope King County
>15% & <=25%
>25% & <=40%
>40% & <=90%
>90%
Environment Designations
Natural
Shoreline High Intensity
Shoreline Isolated High Intensity
Shoreline Residential
Urban Conservancy
Jurisdictions
Streams (Classified)
<all other values>
Type S Shoreline
Type F Fish
Type Np Non-Fish
Type Ns Non-Fish Seasonal
Unclassified
Not Visited
Wetlands
PHILLIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 19
Appendix E – MGS Flood Model Report
SD SD SD
SD
SD SD SD SD
SD
SD
SD
SD
SDSDFD
FD FD
FD
FD
IT
ITITITIT ITITIT
IT
IT IT
ITSD ITITSD SD SD
SD
SD SD SD SD
SD
SD
SD
SD
SDSDFD
FD FD
FD
FD
IT
ITITITIT ITITIT
IT
IT IT
ITSDSD ITITO2
O7
O5
O8
B4
B5
B7
B6
B38
B9
B3
B14
B10
B20
B12
B11
B37
B13
B17B15
B2
B16
B18
B21
B24
B23
B27
B33
B19
B34
B25
B36
B26
B29
B35
B30
B28B32
IT CB15IT CB14
CB12
CB11
O3
CB09O2
IT CB07
IT CB06
CB06
IT CB05
IT CB01
IT CB03
CB03
CB02
CB01
IT FS
BIO RETENTION POND
FILTER STRIP
CB10
IT CB02
IT CB04
IT CB08
IT CB09
IT CB11
XX XX
www.pndengineers.com
1506 West 36th Avenue
Anchorage, Alaska 99503
Phone: 907.561.1011
AK. LIC# AECC250
Philip Arnold Park
MGS FLOOD BASIN MAP
TDA 1 - FLOOD FREQUENCY PLOT - EXISTING CONDITIONS VS. POST-DEVELOPED
TDA 2 - FLOOD FREQUENCY PLOT - FORRESTED CONDITIONS VS. POST-DEVELOPED
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.55
Program License Number: 201210006
Project Simulation Performed on: 10/25/2021 10:07 AM
Report Generation Date: 10/25/2021 10:48 AM
—————————————————————————————————
Input File Name: PA PARK forested.fld
Project Name: PA PARK
Analysis Title: R2
Comments:
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 5
Extended Precipitation Time Series Selected
Climatic Region Number: 14
Full Period of Record Available used for Routing
Precipitation Station : 96003605 Puget East 36 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961036 Puget East 36 in MAP
Evaporation Scale Factor : 0.750
HSPF Parameter Region Number: 1
HSPF Parameter Region Name : USGS Default
********** Default HSPF Parameters Used (Not Modified by User) ***************
********************** WATERSHED DEFINITION ***********************
Predevelopment/Post Development Tributary Area Summary
Predeveloped Post Developed
Total Subbasin Area (acres) 6.753 6.704
Area of Links that Include Precip/Evap (acres) 0.000 0.118
Total (acres) 6.753 6.822
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 4
---------- Subbasin : A ----------
-------Area (Acres) --------
Outwash Grass 0.500
Impervious 0.570
----------------------------------------------
Subbasin Total 1.070
---------- Subbasin : B ----------
-------Area (Acres) --------
Outwash Grass 2.200
Impervious 0.120
----------------------------------------------
Subbasin Total 2.320
---------- Subbasin : C ----------
-------Area (Acres) --------
Outwash Forest 0.410
----------------------------------------------
Subbasin Total 0.410
---------- Subbasin : D ----------
-------Area (Acres) --------
Outwash Forest 2.953
----------------------------------------------
Subbasin Total 2.953
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 34
---------- Subbasin : B3 ----------
-------Area (Acres) --------
Outwash Grass 0.020
----------------------------------------------
Subbasin Total 0.020
---------- Subbasin : B4 ----------
-------Area (Acres) --------
Outwash Grass 0.510
Impervious 0.010
----------------------------------------------
Subbasin Total 0.520
---------- Subbasin : B5 ----------
-------Area (Acres) --------
Outwash Grass 0.660
----------------------------------------------
Subbasin Total 0.660
---------- Subbasin : B6 ----------
-------Area (Acres) --------
Outwash Grass 0.040
----------------------------------------------
Subbasin Total 0.040
---------- Subbasin : B7 ----------
-------Area (Acres) --------
Outwash Grass 0.100
Impervious 0.050
----------------------------------------------
Subbasin Total 0.150
---------- Subbasin : B9 ----------
-------Area (Acres) --------
Outwash Grass 0.250
Impervious 0.020
----------------------------------------------
Subbasin Total 0.270
---------- Subbasin : B18 ----------
-------Area (Acres) --------
Outwash Grass 0.260
Impervious 0.150
----------------------------------------------
Subbasin Total 0.410
---------- Subbasin : B10 ----------
-------Area (Acres) --------
Outwash Grass 0.350
Impervious 0.030
----------------------------------------------
Subbasin Total 0.380
---------- Subbasin : B12 ----------
-------Area (Acres) --------
Outwash Grass 0.140
Impervious 0.020
----------------------------------------------
Subbasin Total 0.160
---------- Subbasin : B11 ----------
-------Area (Acres) --------
Outwash Grass 0.130
Impervious 0.010
----------------------------------------------
Subbasin Total 0.140
---------- Subbasin : B15 ----------
-------Area (Acres) --------
Outwash Grass 0.170
Impervious 0.020
----------------------------------------------
Subbasin Total 0.190
---------- Subbasin : B19 ----------
-------Area (Acres) --------
Outwash Grass 0.080
----------------------------------------------
Subbasin Total 0.080
---------- Subbasin : B16 ----------
-------Area (Acres) --------
Outwash Grass 0.250
Impervious 0.050
----------------------------------------------
Subbasin Total 0.300
---------- Subbasin : B13 ----------
-------Area (Acres) --------
Outwash Grass 0.150
----------------------------------------------
Subbasin Total 0.150
---------- Subbasin : B17 ----------
-------Area (Acres) --------
Outwash Grass 0.020
Impervious 0.050
----------------------------------------------
Subbasin Total 0.070
---------- Subbasin : B20 ----------
-------Area (Acres) --------
Outwash Grass 0.020
Impervious 0.030
----------------------------------------------
Subbasin Total 0.050
---------- Subbasin : B25 ----------
-------Area (Acres) --------
Outwash Grass 0.120
----------------------------------------------
Subbasin Total 0.120
---------- Subbasin : B26 ----------
-------Area (Acres) --------
Outwash Grass 0.190
----------------------------------------------
Subbasin Total 0.190
---------- Subbasin : B21 ----------
-------Area (Acres) --------
Outwash Grass 0.160
Impervious 0.050
----------------------------------------------
Subbasin Total 0.210
---------- Subbasin : B23 ----------
-------Area (Acres) --------
Outwash Grass 0.060
Impervious 0.300
----------------------------------------------
Subbasin Total 0.360
---------- Subbasin : B24 ----------
-------Area (Acres) --------
Outwash Grass 0.120
Impervious 0.170
----------------------------------------------
Subbasin Total 0.290
---------- Subbasin : B28 ----------
-------Area (Acres) --------
Outwash Grass 0.080
Impervious 0.010
----------------------------------------------
Subbasin Total 0.090
---------- Subbasin : B27 ----------
-------Area (Acres) --------
Outwash Grass 0.060
Impervious 0.230
----------------------------------------------
Subbasin Total 0.290
---------- Subbasin : B29 ----------
-------Area (Acres) --------
Outwash Grass 0.200
Impervious 0.020
----------------------------------------------
Subbasin Total 0.220
---------- Subbasin : B30 ----------
-------Area (Acres) --------
Outwash Grass 0.190
Impervious 0.010
----------------------------------------------
Subbasin Total 0.200
---------- Subbasin : B32 ----------
-------Area (Acres) --------
Outwash Grass 0.010
Impervious 0.010
----------------------------------------------
Subbasin Total 0.020
---------- Subbasin : B33 ----------
-------Area (Acres) --------
Outwash Grass 0.140
Impervious 0.100
----------------------------------------------
Subbasin Total 0.240
---------- Subbasin : B34 ----------
-------Area (Acres) --------
Outwash Grass 0.110
Impervious 0.140
----------------------------------------------
Subbasin Total 0.250
---------- Subbasin : B35 ----------
-------Area (Acres) --------
Outwash Grass 0.090
Impervious 0.030
----------------------------------------------
Subbasin Total 0.120
---------- Subbasin : B36 ----------
-------Area (Acres) --------
Outwash Grass 0.060
----------------------------------------------
Subbasin Total 0.060
---------- Subbasin : B37 ----------
-------Area (Acres) --------
Outwash Grass 0.100
----------------------------------------------
Subbasin Total 0.100
---------- Subbasin : B38 ----------
-------Area (Acres) --------
Outwash Grass 0.160
Impervious 0.030
----------------------------------------------
Subbasin Total 0.190
---------- Subbasin : B14 ----------
-------Area (Acres) --------
Outwash Grass 0.060
Impervious 0.020
----------------------------------------------
Subbasin Total 0.080
---------- Subbasin : B2 ----------
-------Area (Acres) --------
Outwash Grass 0.054
Impervious 0.030
----------------------------------------------
Subbasin Total 0.084
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 2
------------------------------------------
Link Name: NORTH
Link Type: Open Channel
Downstream Link: None
----------Left Overbank
Upper Sideslope (z) : 0.500
Upper Width (ft) : 3.000
Middle Sideslope (z) : 10.000
Middle Width (ft) : 10.000
Mannings n : 0.040
----------Main Channel
Lower Sideslope Left (z) : 0.500
Lower Width Left (ft) : 3.000
Lower Sideslope Right (z) : 0.500
Lower Width Right (ft) : 3.000
Mannings n : 0.024
Base Width (ft) : 10.0
Elevation (ft) : 100.00
Channel Slope (ft/ft) : 0.020
Channel Length (ft) : 1000.0
----------Right Overbank
Upper Sideslope (z) : 0.500
Upper Width (ft) : 3.000
Middle Sideslope (z) : 10.000
Middle Width (ft) : 10.000
Mannings n : 0.040
Hydraulic Conductivity (in/hr) : 0.0
Massmann Regression Used to Estimate Hydralic Gradient
Depth to Water Table (ft) : 100.0
Bio-Fouling Potential : Low
Maintenance : Average or Better
------------------------------------------
Link Name: WEST
Link Type: Open Channel
Downstream Link: None
----------Left Overbank
Upper Sideslope (z) : 0.500
Upper Width (ft) : 3.000
Middle Sideslope (z) : 10.000
Middle Width (ft) : 10.000
Mannings n : 0.040
----------Main Channel
Lower Sideslope Left (z) : 0.500
Lower Width Left (ft) : 3.000
Lower Sideslope Right (z) : 0.500
Lower Width Right (ft) : 3.000
Mannings n : 0.024
Base Width (ft) : 10.0
Elevation (ft) : 100.00
Channel Slope (ft/ft) : 0.020
Channel Length (ft) : 1000.0
----------Right Overbank
Upper Sideslope (z) : 0.500
Upper Width (ft) : 3.000
Middle Sideslope (z) : 10.000
Middle Width (ft) : 10.000
Mannings n : 0.040
Hydraulic Conductivity (in/hr) : 0.0
Massmann Regression Used to Estimate Hydralic Gradient
Depth to Water Table (ft) : 100.0
Bio-Fouling Potential : Low
Maintenance : Average or Better
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 24
------------------------------------------
Link Name: O2-CB11
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 116.98
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: CB09-CB04
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 167.10
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: O3-CB09
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 46.20
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: IT CB14 - CB12
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 19.50
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: IT CB09 - IT CB08
Link Type: Infiltration Trench
Downstream Link Name: IT CB07 - CB12
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 103.49
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: IT CB07 - CB12
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 217.28
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: IT CB06 - CB06
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 160.29
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: IT CB03 - IT CB02
Link Type: Infiltration Trench
Downstream Link Name: IT CB01 - CB04
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 126.67
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: IT CB01 - CB04
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 100.78
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: CB02 - CB01
Link Type: Infiltration Trench
Downstream Link Name: NORTH
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 96.78
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.06
------------------------------------------
Link Name: CB01 - O8
Link Type: Infiltration Trench
Downstream Link Name: NORTH
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 82.54
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.06
------------------------------------------
Link Name: Filter Strip
Link Type: Vegetated Filter Strip
Downstream Link Name: O5 - CB02
Length (ft) : 50.0
Width (ft) : 100.0
Mannings n : 0.350
Slope z (ft/ft) : 10.000
Constant Infiltration Option Used
Infiltration Rate (in/hr): 8.00
------------------------------------------
Link Name: WEST
Link Type: Open Channel
Downstream Link: None
----------Left Overbank
Upper Sideslope (z) : 0.500
Upper Width (ft) : 3.000
Middle Sideslope (z) : 10.000
Middle Width (ft) : 10.000
Mannings n : 0.040
----------Main Channel
Lower Sideslope Left (z) : 0.500
Lower Width Left (ft) : 3.000
Lower Sideslope Right (z) : 0.500
Lower Width Right (ft) : 3.000
Mannings n : 0.024
Base Width (ft) : 10.0
Elevation (ft) : 100.00
Channel Slope (ft/ft) : 0.020
Channel Length (ft) : 1000.0
----------Right Overbank
Upper Sideslope (z) : 0.500
Upper Width (ft) : 3.000
Middle Sideslope (z) : 10.000
Middle Width (ft) : 10.000
Mannings n : 0.040
Hydraulic Conductivity (in/hr) : 0.0
Massmann Regression Used to Estimate Hydralic Gradient
Depth to Water Table (ft) : 100.0
Bio-Fouling Potential : Low
Maintenance : Average or Better
------------------------------------------
Link Name: NORTH
Link Type: Open Channel
Downstream Link: None
----------Left Overbank
Upper Sideslope (z) : 0.500
Upper Width (ft) : 3.000
Middle Sideslope (z) : 10.000
Middle Width (ft) : 10.000
Mannings n : 0.040
----------Main Channel
Lower Sideslope Left (z) : 0.500
Lower Width Left (ft) : 3.000
Lower Sideslope Right (z) : 0.500
Lower Width Right (ft) : 3.000
Mannings n : 0.024
Base Width (ft) : 10.0
Elevation (ft) : 100.00
Channel Slope (ft/ft) : 0.020
Channel Length (ft) : 1000.0
----------Right Overbank
Upper Sideslope (z) : 0.500
Upper Width (ft) : 3.000
Middle Sideslope (z) : 10.000
Middle Width (ft) : 10.000
Mannings n : 0.040
Hydraulic Conductivity (in/hr) : 0.0
Massmann Regression Used to Estimate Hydralic Gradient
Depth to Water Table (ft) : 100.0
Bio-Fouling Potential : Low
Maintenance : Average or Better
------------------------------------------
Link Name: IT CB05 - CB06
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 74.87
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: IT CB05-CB06
Link Type: Infiltration Trench
Downstream Link Name: Bio Retention Pond
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 74.87
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: IT CB15 - IT CB14
Link Type: Infiltration Trench
Downstream Link Name: IT CB14 - CB12
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 53.65
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: O5 - CB02
Link Type: Infiltration Trench
Downstream Link Name: NORTH
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 135.08
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: Bio Retention Pond
Link Type: Ecology Bioretention Facility
Downstream Link Name: WEST
Floor Elevation (ft) : 100.00
Riser Crest Elevation (ft) : 101.00
Storage Depth (ft) : 1.00
Bottom Length (ft) : 31.0
Bottom Width (ft) : 5.5
Bottom Slope (ft/ft) : 0.000
Side Slopes (ft/ft) : L1= 3.00 L2= 3.00 W1= 3.00 W2= 3.00
Bottom Area (sq-ft) : 171.
Area at Riser Crest El (sq-ft) : 426.
(acres) : 0.010
Volume at Riser Crest (cu-ft) : 872.
(ac-ft) : 0.020
Infiltration on Bottom and Sideslopes Selected
Soil Properties
Layer No Soil Name Thickness (ft)
1 ASTM 100 1.500
2 SMMWW 12 in/hr (Ecol 1.500
3 GRAVEL 1.500
KSat Safety Factor: None
Native Soil Infiltration Rate (in/hr) : 0.50
Underdrain Not Present
Riser Geometry
Riser Structure Type : Circular
Riser Diameter (in) : 48.00
Common Length (ft) : 0.000
Riser Crest Elevation : 101.00 ft
Hydraulic Structure Geometry
Number of Devices: 0
------------------------------------------
Link Name: IT Filter Strip
Link Type: Infiltration Trench
Downstream Link Name: Filter Strip
Trench Type : Trench on Embankment Sideslope
Trench Length (ft) : 50.00
Trench Width (ft) : 2.50
Trench Depth (ft) : 4.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 8.00
------------------------------------------
Link Name: Playground (B18)
Link Type: Infiltration Trench
Downstream Link Name: IT CB05-CB06
Trench Type : Trench at Toe of Embankment
Trench Length (ft) : 300.00
Trench Width (ft) : 2.00
Trench Depth (ft) : 2.00
Trench Bottom Elev (ft) : 100.00
Trench Rockfill Porosity (%) : 30.00
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: B11 OPEN CHANNEL
Link Type: Open Channel
Downstream Link Name: NORTH
----------Left Overbank
Upper Sideslope (z) : 3.000
Upper Width (ft) : 2.500
Middle Sideslope (z) : 3.000
Middle Width (ft) : 2.500
Mannings n : 0.040
----------Main Channel
Lower Sideslope Left (z) : 3.000
Lower Width Left (ft) : 3.000
Lower Sideslope Right (z) : 3.000
Lower Width Right (ft) : 3.000
Mannings n : 0.024
Base Width (ft) : 0.1
Elevation (ft) : 100.00
Channel Slope (ft/ft) : 0.001
Channel Length (ft) : 143.0
----------Right Overbank
Upper Sideslope (z) : 3.000
Upper Width (ft) : 2.500
Middle Sideslope (z) : 3.000
Middle Width (ft) : 2.500
Mannings n : 0.040
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: B25 OPEN CHANNEL
Link Type: Open Channel
Downstream Link Name: NORTH
----------Left Overbank
Upper Sideslope (z) : 3.000
Upper Width (ft) : 2.500
Middle Sideslope (z) : 3.000
Middle Width (ft) : 2.500
Mannings n : 0.040
----------Main Channel
Lower Sideslope Left (z) : 3.000
Lower Width Left (ft) : 2.500
Lower Sideslope Right (z) : 3.000
Lower Width Right (ft) : 2.500
Mannings n : 0.024
Base Width (ft) : 0.1
Elevation (ft) : 100.00
Channel Slope (ft/ft) : 0.021
Channel Length (ft) : 157.0
----------Right Overbank
Upper Sideslope (z) : 3.000
Upper Width (ft) : 2.500
Middle Sideslope (z) : 3.000
Middle Width (ft) : 2.500
Mannings n : 0.040
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
------------------------------------------
Link Name: B28 OPEN CHANNEL
Link Type: Open Channel
Downstream Link Name: NORTH
----------Left Overbank
Upper Sideslope (z) : 3.000
Upper Width (ft) : 2.500
Middle Sideslope (z) : 3.000
Middle Width (ft) : 2.500
Mannings n : 0.040
----------Main Channel
Lower Sideslope Left (z) : 3.000
Lower Width Left (ft) : 2.500
Lower Sideslope Right (z) : 3.000
Lower Width Right (ft) : 2.500
Mannings n : 0.024
Base Width (ft) : 0.1
Elevation (ft) : 100.00
Channel Slope (ft/ft) : 0.030
Channel Length (ft) : 145.0
----------Right Overbank
Upper Sideslope (z) : 3.000
Upper Width (ft) : 2.500
Middle Sideslope (z) : 3.000
Middle Width (ft) : 2.500
Mannings n : 0.040
Constant Infiltration Option Used
Infiltration Rate (in/hr): 0.50
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 4
Number of Links: 2
********** Subbasin: A **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.259
5-Year 0.343
10-Year 0.427
25-Year 0.531
50-Year 0.657
100-Year 0.832
200-Year 0.964
500-Year 1.139
********** Subbasin: B **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 5.892E-02
5-Year 8.337E-02
10-Year 0.113
25-Year 0.192
50-Year 0.246
100-Year 0.367
200-Year 0.383
500-Year 0.399
********** Subbasin: C **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 8.778E-04
5-Year 9.592E-04
10-Year 9.744E-04
25-Year 9.863E-04
50-Year 9.891E-04
100-Year 9.905E-04
200-Year 9.910E-04
500-Year 9.915E-04
********** Subbasin: D **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 6.322E-03
5-Year 6.909E-03
10-Year 7.018E-03
25-Year 7.104E-03
50-Year 7.124E-03
100-Year 7.134E-03
200-Year 7.137E-03
500-Year 7.141E-03
********** Link: NORTH ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.319
5-Year 0.432
10-Year 0.550
25-Year 0.730
50-Year 0.871
100-Year 1.007
200-Year 1.168
500-Year 1.380
********** Link: NORTH ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.267
5-Year 0.355
10-Year 0.433
25-Year 0.547
50-Year 0.721
100-Year 0.760
200-Year 0.872
500-Year 1.021
********** Link: WEST ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 7.200E-03
5-Year 7.868E-03
10-Year 7.992E-03
25-Year 8.090E-03
50-Year 8.113E-03
100-Year 8.125E-03
200-Year 8.128E-03
500-Year 8.133E-03
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 34
Number of Links: 24
********** Subbasin: B3 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.725E-05
5-Year 8.028E-05
10-Year 3.286E-04
25-Year 1.165E-03
50-Year 1.602E-03
100-Year 2.558E-03
200-Year 2.755E-03
500-Year 2.989E-03
********** Subbasin: B4 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 5.293E-03
5-Year 8.091E-03
10-Year 1.429E-02
25-Year 3.414E-02
50-Year 4.663E-02
100-Year 7.239E-02
200-Year 7.688E-02
500-Year 8.209E-02
********** Subbasin: B5 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.559E-03
5-Year 2.649E-03
10-Year 1.084E-02
25-Year 3.845E-02
50-Year 5.287E-02
100-Year 8.442E-02
200-Year 9.090E-02
500-Year 9.865E-02
********** Subbasin: B6 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.450E-05
5-Year 1.606E-04
10-Year 6.572E-04
25-Year 2.330E-03
50-Year 3.204E-03
100-Year 5.116E-03
200-Year 5.509E-03
500-Year 5.979E-03
********** Subbasin: B7 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.311E-02
5-Year 3.052E-02
10-Year 3.786E-02
25-Year 4.841E-02
50-Year 5.772E-02
100-Year 7.298E-02
200-Year 8.457E-02
500-Year 9.995E-02
********** Subbasin: B9 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.621E-03
5-Year 1.287E-02
10-Year 1.697E-02
25-Year 2.712E-02
50-Year 3.362E-02
100-Year 4.640E-02
200-Year 4.771E-02
500-Year 4.909E-02
********** Subbasin: B18 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 6.855E-02
5-Year 9.155E-02
10-Year 0.113
25-Year 0.142
50-Year 0.173
100-Year 0.219
200-Year 0.254
500-Year 0.300
********** Subbasin: B10 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.440E-02
5-Year 1.931E-02
10-Year 2.528E-02
25-Year 4.068E-02
50-Year 4.901E-02
100-Year 6.646E-02
200-Year 6.812E-02
500-Year 6.991E-02
********** Subbasin: B12 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.525E-03
5-Year 1.273E-02
10-Year 1.675E-02
25-Year 2.256E-02
50-Year 3.043E-02
100-Year 3.259E-02
200-Year 3.498E-02
500-Year 3.820E-02
********** Subbasin: B11 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.811E-03
5-Year 6.436E-03
10-Year 8.630E-03
25-Year 1.356E-02
50-Year 1.709E-02
100-Year 2.383E-02
200-Year 2.454E-02
500-Year 2.529E-02
********** Subbasin: B15 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.568E-03
5-Year 1.287E-02
10-Year 1.676E-02
25-Year 2.512E-02
50-Year 3.176E-02
100-Year 3.636E-02
200-Year 3.669E-02
500-Year 3.714E-02
********** Subbasin: B19 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.890E-04
5-Year 3.211E-04
10-Year 1.314E-03
25-Year 4.661E-03
50-Year 6.408E-03
100-Year 1.023E-02
200-Year 1.102E-02
500-Year 1.196E-02
********** Subbasin: B16 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.337E-02
5-Year 3.134E-02
10-Year 3.986E-02
25-Year 5.305E-02
50-Year 6.765E-02
100-Year 7.304E-02
200-Year 8.462E-02
500-Year 0.100
********** Subbasin: B13 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.544E-04
5-Year 6.021E-04
10-Year 2.465E-03
25-Year 8.739E-03
50-Year 1.202E-02
100-Year 1.919E-02
200-Year 2.066E-02
500-Year 2.242E-02
********** Subbasin: B17 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.245E-02
5-Year 3.010E-02
10-Year 3.691E-02
25-Year 4.658E-02
50-Year 5.756E-02
100-Year 7.298E-02
200-Year 8.455E-02
500-Year 9.989E-02
********** Subbasin: B20 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.354E-02
5-Year 1.807E-02
10-Year 2.246E-02
25-Year 2.795E-02
50-Year 3.455E-02
100-Year 4.379E-02
200-Year 5.073E-02
500-Year 5.994E-02
********** Subbasin: B25 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.835E-04
5-Year 4.817E-04
10-Year 1.972E-03
25-Year 6.991E-03
50-Year 9.612E-03
100-Year 1.535E-02
200-Year 1.653E-02
500-Year 1.794E-02
********** Subbasin: B26 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.489E-04
5-Year 7.627E-04
10-Year 3.122E-03
25-Year 1.107E-02
50-Year 1.522E-02
100-Year 2.430E-02
200-Year 2.617E-02
500-Year 2.840E-02
********** Subbasin: B21 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.314E-02
5-Year 3.107E-02
10-Year 3.898E-02
25-Year 5.286E-02
50-Year 6.014E-02
100-Year 7.298E-02
200-Year 8.459E-02
500-Year 9.999E-02
********** Subbasin: B23 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.134
5-Year 0.180
10-Year 0.221
25-Year 0.279
50-Year 0.345
100-Year 0.438
200-Year 0.507
500-Year 0.599
********** Subbasin: B24 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 7.686E-02
5-Year 0.102
10-Year 0.127
25-Year 0.158
50-Year 0.196
100-Year 0.248
200-Year 0.287
500-Year 0.340
********** Subbasin: B28 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.773E-03
5-Year 6.435E-03
10-Year 8.377E-03
25-Year 1.213E-02
50-Year 1.568E-02
100-Year 1.771E-02
200-Year 1.797E-02
500-Year 1.831E-02
********** Subbasin: B27 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.103
5-Year 0.138
10-Year 0.170
25-Year 0.214
50-Year 0.265
100-Year 0.336
200-Year 0.389
500-Year 0.459
********** Subbasin: B29 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.596E-03
5-Year 1.287E-02
10-Year 1.676E-02
25-Year 2.673E-02
50-Year 3.177E-02
100-Year 4.012E-02
200-Year 4.082E-02
500-Year 4.162E-02
********** Subbasin: B30 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.945E-03
5-Year 7.068E-03
10-Year 9.591E-03
25-Year 1.639E-02
50-Year 2.100E-02
100-Year 3.146E-02
200-Year 3.281E-02
500-Year 3.426E-02
********** Subbasin: B32 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.552E-03
5-Year 6.028E-03
10-Year 7.488E-03
25-Year 9.317E-03
50-Year 1.152E-02
100-Year 1.460E-02
200-Year 1.691E-02
500-Year 1.998E-02
********** Subbasin: B33 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.552E-02
5-Year 6.103E-02
10-Year 7.489E-02
25-Year 9.317E-02
50-Year 0.115
100-Year 0.146
200-Year 0.169
500-Year 0.200
********** Subbasin: B34 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 6.355E-02
5-Year 8.434E-02
10-Year 0.105
25-Year 0.130
50-Year 0.161
100-Year 0.204
200-Year 0.237
500-Year 0.280
********** Subbasin: B35 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.389E-02
5-Year 1.853E-02
10-Year 2.300E-02
25-Year 3.170E-02
50-Year 3.559E-02
100-Year 4.379E-02
200-Year 5.075E-02
500-Year 5.999E-02
********** Subbasin: B36 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.417E-04
5-Year 2.408E-04
10-Year 9.858E-04
25-Year 3.496E-03
50-Year 4.806E-03
100-Year 7.674E-03
200-Year 8.264E-03
500-Year 8.968E-03
********** Subbasin: B37 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.362E-04
5-Year 4.014E-04
10-Year 1.643E-03
25-Year 5.826E-03
50-Year 8.010E-03
100-Year 1.279E-02
200-Year 1.377E-02
500-Year 1.495E-02
********** Subbasin: B38 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.411E-02
5-Year 1.880E-02
10-Year 2.402E-02
25-Year 3.185E-02
50-Year 4.197E-02
100-Year 4.386E-02
200-Year 5.078E-02
500-Year 6.004E-02
********** Subbasin: B14 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.258E-03
5-Year 1.235E-02
10-Year 1.533E-02
25-Year 2.113E-02
50-Year 2.373E-02
100-Year 2.919E-02
200-Year 3.384E-02
500-Year 3.999E-02
********** Subbasin: B2 **********
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.376E-02
5-Year 1.831E-02
10-Year 2.264E-02
25-Year 2.869E-02
50-Year 3.462E-02
100-Year 4.379E-02
200-Year 5.074E-02
500-Year 5.996E-02
********** Link: O2-CB11 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.311E-02
5-Year 3.052E-02
10-Year 3.786E-02
25-Year 4.841E-02
50-Year 5.772E-02
100-Year 7.298E-02
200-Year 8.457E-02
500-Year 9.995E-02
********** Link: O2-CB11 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 5.322E-06
5-Year 7.890E-06
10-Year 9.850E-06
25-Year 1.185E-02
50-Year 1.505E-02
100-Year 2.981E-02
200-Year 3.509E-02
500-Year 4.172E-02
********** Link: CB09-CB04 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.440E-02
5-Year 1.931E-02
10-Year 2.528E-02
25-Year 4.068E-02
50-Year 4.901E-02
100-Year 6.646E-02
200-Year 6.812E-02
500-Year 6.991E-02
********** Link: CB09-CB04 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.198E-06
5-Year 1.953E-06
10-Year 2.694E-06
25-Year 3.671E-06
50-Year 4.763E-06
100-Year 8.919E-06
200-Year 1.553E-02
500-Year 3.646E-02
********** Link: O3-CB09 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 5.293E-03
5-Year 8.091E-03
10-Year 1.429E-02
25-Year 3.414E-02
50-Year 4.663E-02
100-Year 7.239E-02
200-Year 7.688E-02
500-Year 8.209E-02
********** Link: O3-CB09 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.119E-06
5-Year 3.512E-06
10-Year 4.675E-06
25-Year 8.420E-06
50-Year 1.545E-02
100-Year 6.354E-02
200-Year 7.165E-02
500-Year 8.137E-02
********** Link: IT CB14 - CB12 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 8.079E-08
5-Year 1.379E-07
10-Year 1.393E-06
25-Year 4.882E-06
50-Year 1.213E-02
100-Year 7.591E-02
200-Year 8.546E-02
500-Year 9.675E-02
********** Link: IT CB14 - CB12 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.604E-11
5-Year 4.343E-11
10-Year 4.833E-10
25-Year 1.817E-09
50-Year 2.139E-03
100-Year 7.365E-02
200-Year 8.386E-02
500-Year 9.506E-02
********** Link: IT CB09 - IT CB08 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.308E-02
5-Year 4.399E-02
10-Year 5.688E-02
25-Year 7.499E-02
50-Year 0.103
100-Year 0.105
200-Year 0.119
500-Year 0.139
********** Link: IT CB09 - IT CB08 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.943E-06
5-Year 1.827E-02
10-Year 2.637E-02
25-Year 4.803E-02
50-Year 6.797E-02
100-Year 8.613E-02
200-Year 9.325E-02
500-Year 0.102
********** Link: IT CB07 - CB12 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.578E-02
5-Year 5.421E-02
10-Year 6.790E-02
25-Year 9.897E-02
50-Year 0.136
100-Year 0.163
200-Year 0.174
500-Year 0.188
********** Link: IT CB07 - CB12 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.675E-06
5-Year 7.498E-06
10-Year 2.126E-02
25-Year 3.677E-02
50-Year 4.971E-02
100-Year 0.133
200-Year 0.154
500-Year 0.180
********** Link: IT CB06 - CB06 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.544E-04
5-Year 6.021E-04
10-Year 2.465E-03
25-Year 8.739E-03
50-Year 1.202E-02
100-Year 1.919E-02
200-Year 2.066E-02
500-Year 2.242E-02
********** Link: IT CB06 - CB06 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.638E-09
5-Year 5.608E-09
10-Year 2.472E-08
25-Year 1.747E-07
50-Year 3.965E-07
100-Year 1.263E-06
200-Year 1.871E-06
500-Year 2.665E-06
********** Link: IT CB03 - IT CB02 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.314E-02
5-Year 3.107E-02
10-Year 3.898E-02
25-Year 5.286E-02
50-Year 6.014E-02
100-Year 7.298E-02
200-Year 8.459E-02
500-Year 9.999E-02
********** Link: IT CB03 - IT CB02 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.791E-06
5-Year 7.089E-06
10-Year 9.061E-06
25-Year 7.879E-03
50-Year 1.493E-02
100-Year 3.633E-02
200-Year 4.252E-02
500-Year 5.016E-02
********** Link: IT CB01 - CB04 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.791E-06
5-Year 7.089E-06
10-Year 9.061E-06
25-Year 7.879E-03
50-Year 1.493E-02
100-Year 3.633E-02
200-Year 4.252E-02
500-Year 5.016E-02
********** Link: IT CB01 - CB04 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.016E-10
5-Year 1.505E-10
10-Year 1.919E-10
25-Year 3.690E-07
50-Year 2.315E-06
100-Year 3.791E-06
200-Year 4.586E-06
500-Year 5.636E-06
********** Link: CB02 - CB01 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.596E-03
5-Year 1.287E-02
10-Year 1.676E-02
25-Year 2.673E-02
50-Year 3.177E-02
100-Year 4.012E-02
200-Year 4.082E-02
500-Year 4.162E-02
********** Link: CB02 - CB01 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 7.173E-06
5-Year 1.175E-03
10-Year 5.838E-03
25-Year 1.349E-02
50-Year 2.275E-02
100-Year 3.392E-02
200-Year 3.810E-02
500-Year 4.346E-02
********** Link: CB01 - O8 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.945E-03
5-Year 7.068E-03
10-Year 9.591E-03
25-Year 1.639E-02
50-Year 2.100E-02
100-Year 3.146E-02
200-Year 3.281E-02
500-Year 3.426E-02
********** Link: CB01 - O8 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.674E-06
5-Year 5.504E-06
10-Year 7.223E-06
25-Year 2.875E-04
50-Year 2.865E-03
100-Year 4.442E-03
200-Year 1.994E-02
500-Year 4.080E-02
********** Link: Filter Strip ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.252
5-Year 0.374
10-Year 0.493
25-Year 0.644
50-Year 0.819
100-Year 1.066
200-Year 1.250
500-Year 1.494
********** Link: Filter Strip ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.452E-02
5-Year 0.140
10-Year 0.185
25-Year 0.239
50-Year 0.297
100-Year 0.387
200-Year 0.452
500-Year 0.539
********** Link: WEST ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.727E-05
5-Year 8.030E-05
10-Year 3.287E-04
25-Year 1.165E-03
50-Year 1.602E-03
100-Year 2.558E-03
200-Year 2.759E-03
500-Year 3.000E-03
********** Link: NORTH ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.129
5-Year 0.226
10-Year 0.303
25-Year 0.425
50-Year 0.496
100-Year 0.661
200-Year 0.749
500-Year 0.866
********** Link: NORTH ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.114
5-Year 0.187
10-Year 0.239
25-Year 0.301
50-Year 0.401
100-Year 0.467
200-Year 0.563
500-Year 0.691
********** Link: IT CB05 - CB06 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.362E-04
5-Year 4.014E-04
10-Year 1.643E-03
25-Year 5.826E-03
50-Year 8.010E-03
100-Year 1.279E-02
200-Year 1.377E-02
500-Year 1.495E-02
********** Link: IT CB05 - CB06 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 5.188E-09
5-Year 7.980E-09
10-Year 3.519E-08
25-Year 3.111E-07
50-Year 6.869E-07
100-Year 2.071E-06
200-Year 3.068E-06
500-Year 4.374E-06
********** Link: IT CB05-CB06 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 6.652E-06
5-Year 9.768E-06
10-Year 2.989E-02
25-Year 5.088E-02
50-Year 6.380E-02
100-Year 8.594E-02
200-Year 9.746E-02
500-Year 0.112
********** Link: IT CB05-CB06 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.894E-10
5-Year 2.782E-10
10-Year 7.053E-06
25-Year 2.796E-02
50-Year 4.015E-02
100-Year 7.998E-02
200-Year 9.203E-02
500-Year 0.107
********** Link: IT CB15 - IT CB14 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 1.559E-03
5-Year 2.649E-03
10-Year 1.084E-02
25-Year 3.845E-02
50-Year 5.287E-02
100-Year 8.442E-02
200-Year 9.090E-02
500-Year 9.865E-02
********** Link: IT CB15 - IT CB14 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 8.079E-08
5-Year 1.379E-07
10-Year 1.393E-06
25-Year 4.882E-06
50-Year 1.213E-02
100-Year 7.591E-02
200-Year 8.546E-02
500-Year 9.675E-02
********** Link: O5 - CB02 ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.107
5-Year 0.156
10-Year 0.206
25-Year 0.267
50-Year 0.332
100-Year 0.430
200-Year 0.498
500-Year 0.589
********** Link: O5 - CB02 ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 6.927E-02
5-Year 0.136
10-Year 0.183
25-Year 0.253
50-Year 0.318
100-Year 0.420
200-Year 0.489
500-Year 0.580
********** Link: Bio Retention Pond ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 6.151E-02
5-Year 8.469E-02
10-Year 0.109
25-Year 0.153
50-Year 0.206
100-Year 0.505
200-Year 0.579
500-Year 0.668
********** Link: Bio Retention Pond ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 9.344E-08
5-Year 1.280E-07
10-Year 2.001E-07
25-Year 8.729E-07
50-Year 1.817E-06
100-Year 8.543E-06
200-Year 9.216E-06
500-Year 9.869E-06
********** Link: Bio Retention Pond ********** Link WSEL Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) WSEL Peak (ft)
======================================
1.05-Year 100.005
1.11-Year 100.006
1.25-Year 100.006
2.00-Year 100.009
3.33-Year 100.011
5-Year 100.013
10-Year 100.020
25-Year 100.087
50-Year 100.182
100-Year 100.854
********** Link: IT Filter Strip ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.359
5-Year 0.482
10-Year 0.594
25-Year 0.745
50-Year 0.921
100-Year 1.168
200-Year 1.353
500-Year 1.598
********** Link: IT Filter Strip ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.252
5-Year 0.374
10-Year 0.493
25-Year 0.644
50-Year 0.819
100-Year 1.066
200-Year 1.250
500-Year 1.494
********** Link: Playground (B18) ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 6.855E-02
5-Year 9.155E-02
10-Year 0.113
25-Year 0.142
50-Year 0.173
100-Year 0.219
200-Year 0.254
500-Year 0.300
********** Link: Playground (B18) ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 6.652E-06
5-Year 9.768E-06
10-Year 2.989E-02
25-Year 5.088E-02
50-Year 6.380E-02
100-Year 8.594E-02
200-Year 9.746E-02
500-Year 0.112
********** Link: B11 OPEN CHANNEL ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.811E-03
5-Year 6.436E-03
10-Year 8.630E-03
25-Year 1.356E-02
50-Year 1.709E-02
100-Year 2.383E-02
200-Year 2.454E-02
500-Year 2.529E-02
********** Link: B11 OPEN CHANNEL ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.316E-03
5-Year 4.524E-03
10-Year 6.150E-03
25-Year 1.037E-02
50-Year 1.291E-02
100-Year 1.809E-02
200-Year 1.948E-02
500-Year 2.116E-02
********** Link: B25 OPEN CHANNEL ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.252E-04
5-Year 7.225E-04
10-Year 2.957E-03
25-Year 1.049E-02
50-Year 1.442E-02
100-Year 2.302E-02
200-Year 2.479E-02
500-Year 2.690E-02
********** Link: B25 OPEN CHANNEL ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.524E-04
5-Year 3.883E-04
10-Year 1.914E-03
25-Year 8.631E-03
50-Year 1.159E-02
100-Year 2.072E-02
200-Year 2.123E-02
500-Year 2.163E-02
********** Link: B28 OPEN CHANNEL ********** Link Inflow Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 4.773E-03
5-Year 6.435E-03
10-Year 8.377E-03
25-Year 1.213E-02
50-Year 1.568E-02
100-Year 1.771E-02
200-Year 1.797E-02
500-Year 1.831E-02
********** Link: B28 OPEN CHANNEL ********** Link Outflow 1 Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 3.934E-03
5-Year 5.346E-03
10-Year 7.085E-03
25-Year 1.038E-02
50-Year 1.370E-02
100-Year 1.575E-02
200-Year 1.609E-02
500-Year 1.652E-02
***********Groundwater Recharge Summary *************
Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures
Total Predeveloped Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: A 141.260
Subbasin: B 621.546
Subbasin: C 89.711
Subbasin: D 646.140
Link: NORTH 0.000
Link: WEST 0.000
_____________________________________
Total: 1498.657
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: B3 5.650
Subbasin: B4 144.086
Subbasin: B5 186.464
Subbasin: B6 11.301
Subbasin: B7 28.252
Subbasin: B9 70.630
Subbasin: B18 73.455
Subbasin: B10 98.882
Subbasin: B12 39.553
Subbasin: B11 36.728
Subbasin: B15 48.029
Subbasin: B19 22.602
Subbasin: B16 70.630
Subbasin: B13 42.378
Subbasin: B17 5.650
Subbasin: B20 5.650
Subbasin: B25 33.902
Subbasin: B26 53.679
Subbasin: B21 45.203
Subbasin: B23 16.951
Subbasin: B24 33.902
Subbasin: B28 22.602
Subbasin: B27 16.951
Subbasin: B29 56.504
Subbasin: B30 53.679
Subbasin: B32 2.825
Subbasin: B33 39.553
Subbasin: B34 31.077
Subbasin: B35 25.427
Subbasin: B36 16.951
Subbasin: B37 28.252
Subbasin: B38 45.203
Subbasin: B14 16.951
Subbasin: B2 15.256
Link: O2-CB11 19.768
Link: CB09-CB04 12.024
Link: O3-CB09 4.214
Link: IT CB14 - CB12 0.009
Link: IT CB09 - IT CB08 27.647
Link: IT CB07 - CB12 27.932
Link: IT CB06 - CB06 0.079
Link: IT CB03 - IT CB02 19.818
Link: IT CB01 - CB04 0.009
Link: CB02 - CB01 7.933
Link: CB01 - O8 4.044
Link: Filter Strip 38.752
Link: WEST 0.000
Link: NORTH 0.000
Link: IT CB05 - CB06 0.052
Link: IT CB05-CB06 0.065
Link: IT CB15 - IT CB14 0.346
Link: O5 - CB02 30.617
Link: Bio Retention Pond 51.765
Link: IT Filter Strip 307.721
Link: Playground (B18) 59.233
Link: B11 OPEN CHANNEL 1.757
Link: B25 OPEN CHANNEL 0.021
Link: B28 OPEN CHANNEL 0.757
_____________________________________
Total: 2059.376
Total Predevelopment Recharge is Less than Post Developed
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 9.485 ac-ft/year, Post Developed: 13.034 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 2
********** Link: NORTH **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 273.75
Inflow Volume Including PPT-Evap (ac-ft): 273.75
Total Runoff Infiltrated (ac-ft): 0.00, 0.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 273.75
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00%
********** Link: WEST **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.61
Inflow Volume Including PPT-Evap (ac-ft): 0.61
Total Runoff Infiltrated (ac-ft): 0.00, 0.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.61
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00%
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 24
********** Link: O2-CB11 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 19.79
Inflow Volume Including PPT-Evap (ac-ft): 19.79
Total Runoff Infiltrated (ac-ft): 19.77, 99.91%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 99.91%
********** Link: CB09-CB04 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 12.02
Inflow Volume Including PPT-Evap (ac-ft): 12.02
Total Runoff Infiltrated (ac-ft): 12.02, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.00
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: O3-CB09 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 4.21
Inflow Volume Including PPT-Evap (ac-ft): 4.21
Total Runoff Infiltrated (ac-ft): 4.21, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: IT CB14 - CB12 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.01
Inflow Volume Including PPT-Evap (ac-ft): 0.01
Total Runoff Infiltrated (ac-ft): 0.01, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: IT CB09 - IT CB08 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 27.85
Inflow Volume Including PPT-Evap (ac-ft): 27.85
Total Runoff Infiltrated (ac-ft): 27.65, 99.28%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.20
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 99.28%
********** Link: IT CB07 - CB12 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 27.97
Inflow Volume Including PPT-Evap (ac-ft): 27.97
Total Runoff Infiltrated (ac-ft): 27.93, 99.88%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.05
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 99.88%
********** Link: IT CB06 - CB06 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.08
Inflow Volume Including PPT-Evap (ac-ft): 0.08
Total Runoff Infiltrated (ac-ft): 0.08, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.00
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: IT CB03 - IT CB02 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 19.82
Inflow Volume Including PPT-Evap (ac-ft): 19.82
Total Runoff Infiltrated (ac-ft): 19.82, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: IT CB01 - CB04 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.01
Inflow Volume Including PPT-Evap (ac-ft): 0.01
Total Runoff Infiltrated (ac-ft): 0.01, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.00
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: CB02 - CB01 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 8.00
Inflow Volume Including PPT-Evap (ac-ft): 8.00
Total Runoff Infiltrated (ac-ft): 7.93, 99.18%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.07
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 99.18%
********** Link: CB01 - O8 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 4.05
Inflow Volume Including PPT-Evap (ac-ft): 4.05
Total Runoff Infiltrated (ac-ft): 4.04, 99.93%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 99.93%
********** Link: Filter Strip **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 8.14
Inflow Volume Including PPT-Evap (ac-ft): 59.10
Total Runoff Infiltrated (ac-ft): 38.75, 65.57%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 20.30
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 65.57%
********** Link: WEST **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.01
Inflow Volume Including PPT-Evap (ac-ft): 0.01
Total Runoff Infiltrated (ac-ft): 0.00, 0.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00%
********** Link: NORTH **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 66.56
Inflow Volume Including PPT-Evap (ac-ft): 66.56
Total Runoff Infiltrated (ac-ft): 0.00, 0.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 66.56
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00%
********** Link: IT CB05 - CB06 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.05
Inflow Volume Including PPT-Evap (ac-ft): 0.05
Total Runoff Infiltrated (ac-ft): 0.05, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.00
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: IT CB05-CB06 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.09
Inflow Volume Including PPT-Evap (ac-ft): 0.09
Total Runoff Infiltrated (ac-ft): 0.07, 73.27%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.02
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 73.27%
********** Link: IT CB15 - IT CB14 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.35
Inflow Volume Including PPT-Evap (ac-ft): 0.35
Total Runoff Infiltrated (ac-ft): 0.35, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.01
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: O5 - CB02 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 32.19
Inflow Volume Including PPT-Evap (ac-ft): 32.19
Total Runoff Infiltrated (ac-ft): 30.62, 95.12%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 1.50
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 95.12%
********** Link: Bio Retention Pond **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 51.66
Inflow Volume Including PPT-Evap (ac-ft): 51.77
Total Runoff Infiltrated (ac-ft): 51.77, 100.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.00
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00%
********** Link: IT Filter Strip **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 315.95
Inflow Volume Including PPT-Evap (ac-ft): 315.95
Total Runoff Infiltrated (ac-ft): 307.72, 97.40%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 8.14
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 97.40%
********** Link: Playground (B18) **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 59.34
Inflow Volume Including PPT-Evap (ac-ft): 59.34
Total Runoff Infiltrated (ac-ft): 59.23, 99.82%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.09
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 99.82%
********** Link: B11 OPEN CHANNEL **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 4.02
Inflow Volume Including PPT-Evap (ac-ft): 4.02
Total Runoff Infiltrated (ac-ft): 1.76, 43.77%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 2.27
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 43.77%
********** Link: B25 OPEN CHANNEL **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 0.09
Inflow Volume Including PPT-Evap (ac-ft): 0.09
Total Runoff Infiltrated (ac-ft): 0.02, 22.24%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 0.07
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 22.24%
********** Link: B28 OPEN CHANNEL **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 3.99
Inflow Volume Including PPT-Evap (ac-ft): 3.99
Total Runoff Infiltrated (ac-ft): 0.76, 18.99%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 3.24
Secondary Outflow To Downstream System (ac-ft): 0.00
Volume Lost to ET (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 18.99%
***********Compliance Point Results *************
Scenario Predeveloped Compliance Link: WEST
Scenario Postdeveloped Compliance Link: WEST
*** Point of Compliance Flow Frequency Data ***
Recurrence Interval Computed Using Gringorten Plotting Position
Predevelopment Runoff Postdevelopment Runoff
Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs)
----------------------------------------------------------------------------------------------------------------------
2-Year 3.647E-03 2-Year 0.000
5-Year 4.517E-03 5-Year 0.000
10-Year 4.913E-03 10-Year 2.091E-04
25-Year 5.586E-03 25-Year 8.142E-04
50-Year 5.918E-03 50-Year 1.154E-03
100-Year 6.102E-03 100-Year 2.015E-03
200-Year 7.051E-03 200-Year 2.070E-03
500-Year 8.325E-03 500-Year 2.117E-03
** Record too Short to Compute Peak Discharge for These Recurrence Intervals
**** Flow Duration Performance ****
Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): -99.8% PASS
Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): -99.8% PASS
Maximum Excursion from Q2 to Q50 (Must be less than 10%): -89.1% PASS
Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS
-------------------------------------------------------------------------------------------------
MEETS ALL FLOW DURATION DESIGN CRITERIA: PASS
-------------------------------------------------------------------------------------------------
**** LID Duration Performance ****
Excursion at Predeveloped 8%Q2 (Must be Less Than 0%): -99.8% PASS
Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): -99.7% PASS
-------------------------------------------------------------------------------------------------
MEETS ALL LID DURATION DESIGN CRITERIA: PASS
-------------------------------------------------------------------------------------------------
**********************SEASONAL FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
********** Subbasin: A **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.259
0.200 0.343
0.100 0.427
0.040 0.531
0.020 0.657
0.010 0.832
0.005 0.964
0.002 1.139
********** Subbasin: B **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 5.892E-02
0.200 8.337E-02
0.100 0.113
0.040 0.192
0.020 0.246
0.010 0.367
0.005 0.383
0.002 0.399
********** Subbasin: C **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 8.778E-04
0.200 9.592E-04
0.100 9.744E-04
0.040 9.863E-04
0.020 9.891E-04
0.010 9.905E-04
0.005 9.910E-04
0.002 9.915E-04
********** Subbasin: D **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 6.322E-03
0.200 6.909E-03
0.100 7.018E-03
0.040 7.104E-03
0.020 7.124E-03
0.010 7.134E-03
0.005 7.137E-03
0.002 7.141E-03
********** Link: NORTH ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.319
0.200 0.432
0.100 0.550
0.040 0.730
0.020 0.871
0.010 1.007
0.005 1.168
0.002 1.380
********** Link: NORTH ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.267
0.200 0.355
0.100 0.433
0.040 0.547
0.020 0.721
0.010 0.760
0.005 0.872
0.002 1.021
********** Link: WEST ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 7.200E-03
0.200 7.868E-03
0.100 7.992E-03
0.040 8.090E-03
0.020 8.113E-03
0.010 8.125E-03
0.005 8.128E-03
0.002 8.133E-03
********** Link: WEST ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.647E-03
0.200 4.517E-03
0.100 4.913E-03
0.040 5.586E-03
0.020 5.918E-03
0.010 6.102E-03
0.005 7.051E-03
0.002 8.325E-03
----------------------SCENARIO: POSTDEVELOPED
********** Subbasin: B3 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.725E-05
0.200 8.028E-05
0.100 3.286E-04
0.040 1.165E-03
0.020 1.602E-03
0.010 2.558E-03
0.005 2.755E-03
0.002 2.989E-03
********** Subbasin: B4 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 5.293E-03
0.200 8.091E-03
0.100 1.429E-02
0.040 3.414E-02
0.020 4.663E-02
0.010 7.239E-02
0.005 7.688E-02
0.002 8.209E-02
********** Subbasin: B5 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.559E-03
0.200 2.649E-03
0.100 1.084E-02
0.040 3.845E-02
0.020 5.287E-02
0.010 8.442E-02
0.005 9.090E-02
0.002 9.865E-02
********** Subbasin: B6 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.450E-05
0.200 1.606E-04
0.100 6.572E-04
0.040 2.330E-03
0.020 3.204E-03
0.010 5.116E-03
0.005 5.509E-03
0.002 5.979E-03
********** Subbasin: B7 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.311E-02
0.200 3.052E-02
0.100 3.786E-02
0.040 4.841E-02
0.020 5.772E-02
0.010 7.298E-02
0.005 8.457E-02
0.002 9.995E-02
********** Subbasin: B9 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.621E-03
0.200 1.287E-02
0.100 1.697E-02
0.040 2.712E-02
0.020 3.362E-02
0.010 4.640E-02
0.005 4.771E-02
0.002 4.909E-02
********** Subbasin: B18 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 6.855E-02
0.200 9.155E-02
0.100 0.113
0.040 0.142
0.020 0.173
0.010 0.219
0.005 0.254
0.002 0.300
********** Subbasin: B10 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.440E-02
0.200 1.931E-02
0.100 2.528E-02
0.040 4.068E-02
0.020 4.901E-02
0.010 6.646E-02
0.005 6.812E-02
0.002 6.991E-02
********** Subbasin: B12 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.525E-03
0.200 1.273E-02
0.100 1.675E-02
0.040 2.256E-02
0.020 3.043E-02
0.010 3.259E-02
0.005 3.498E-02
0.002 3.820E-02
********** Subbasin: B11 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.811E-03
0.200 6.436E-03
0.100 8.630E-03
0.040 1.356E-02
0.020 1.709E-02
0.010 2.383E-02
0.005 2.454E-02
0.002 2.529E-02
********** Subbasin: B15 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.568E-03
0.200 1.287E-02
0.100 1.676E-02
0.040 2.512E-02
0.020 3.176E-02
0.010 3.636E-02
0.005 3.669E-02
0.002 3.714E-02
********** Subbasin: B19 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.890E-04
0.200 3.211E-04
0.100 1.314E-03
0.040 4.661E-03
0.020 6.408E-03
0.010 1.023E-02
0.005 1.102E-02
0.002 1.196E-02
********** Subbasin: B16 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.337E-02
0.200 3.134E-02
0.100 3.986E-02
0.040 5.305E-02
0.020 6.765E-02
0.010 7.304E-02
0.005 8.462E-02
0.002 0.100
********** Subbasin: B13 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.544E-04
0.200 6.021E-04
0.100 2.465E-03
0.040 8.739E-03
0.020 1.202E-02
0.010 1.919E-02
0.005 2.066E-02
0.002 2.242E-02
********** Subbasin: B17 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.245E-02
0.200 3.010E-02
0.100 3.691E-02
0.040 4.658E-02
0.020 5.756E-02
0.010 7.298E-02
0.005 8.455E-02
0.002 9.989E-02
********** Subbasin: B20 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.354E-02
0.200 1.807E-02
0.100 2.246E-02
0.040 2.795E-02
0.020 3.455E-02
0.010 4.379E-02
0.005 5.073E-02
0.002 5.994E-02
********** Subbasin: B25 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.835E-04
0.200 4.817E-04
0.100 1.972E-03
0.040 6.991E-03
0.020 9.612E-03
0.010 1.535E-02
0.005 1.653E-02
0.002 1.794E-02
********** Subbasin: B26 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.489E-04
0.200 7.627E-04
0.100 3.122E-03
0.040 1.107E-02
0.020 1.522E-02
0.010 2.430E-02
0.005 2.617E-02
0.002 2.840E-02
********** Subbasin: B21 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.314E-02
0.200 3.107E-02
0.100 3.898E-02
0.040 5.286E-02
0.020 6.014E-02
0.010 7.298E-02
0.005 8.459E-02
0.002 9.999E-02
********** Subbasin: B23 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.134
0.200 0.180
0.100 0.221
0.040 0.279
0.020 0.345
0.010 0.438
0.005 0.507
0.002 0.599
********** Subbasin: B24 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 7.686E-02
0.200 0.102
0.100 0.127
0.040 0.158
0.020 0.196
0.010 0.248
0.005 0.287
0.002 0.340
********** Subbasin: B28 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.773E-03
0.200 6.435E-03
0.100 8.377E-03
0.040 1.213E-02
0.020 1.568E-02
0.010 1.771E-02
0.005 1.797E-02
0.002 1.831E-02
********** Subbasin: B27 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.103
0.200 0.138
0.100 0.170
0.040 0.214
0.020 0.265
0.010 0.336
0.005 0.389
0.002 0.459
********** Subbasin: B29 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.596E-03
0.200 1.287E-02
0.100 1.676E-02
0.040 2.673E-02
0.020 3.177E-02
0.010 4.012E-02
0.005 4.082E-02
0.002 4.162E-02
********** Subbasin: B30 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.945E-03
0.200 7.068E-03
0.100 9.591E-03
0.040 1.639E-02
0.020 2.100E-02
0.010 3.146E-02
0.005 3.281E-02
0.002 3.426E-02
********** Subbasin: B32 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.552E-03
0.200 6.028E-03
0.100 7.488E-03
0.040 9.317E-03
0.020 1.152E-02
0.010 1.460E-02
0.005 1.691E-02
0.002 1.998E-02
********** Subbasin: B33 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.552E-02
0.200 6.103E-02
0.100 7.489E-02
0.040 9.317E-02
0.020 0.115
0.010 0.146
0.005 0.169
0.002 0.200
********** Subbasin: B34 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 6.355E-02
0.200 8.434E-02
0.100 0.105
0.040 0.130
0.020 0.161
0.010 0.204
0.005 0.237
0.002 0.280
********** Subbasin: B35 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.389E-02
0.200 1.853E-02
0.100 2.300E-02
0.040 3.170E-02
0.020 3.559E-02
0.010 4.379E-02
0.005 5.075E-02
0.002 5.999E-02
********** Subbasin: B36 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.417E-04
0.200 2.408E-04
0.100 9.858E-04
0.040 3.496E-03
0.020 4.806E-03
0.010 7.674E-03
0.005 8.264E-03
0.002 8.968E-03
********** Subbasin: B37 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.362E-04
0.200 4.014E-04
0.100 1.643E-03
0.040 5.826E-03
0.020 8.010E-03
0.010 1.279E-02
0.005 1.377E-02
0.002 1.495E-02
********** Subbasin: B38 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.411E-02
0.200 1.880E-02
0.100 2.402E-02
0.040 3.185E-02
0.020 4.197E-02
0.010 4.386E-02
0.005 5.078E-02
0.002 6.004E-02
********** Subbasin: B14 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.258E-03
0.200 1.235E-02
0.100 1.533E-02
0.040 2.113E-02
0.020 2.373E-02
0.010 2.919E-02
0.005 3.384E-02
0.002 3.999E-02
********** Subbasin: B2 **********
Season: 10/1 - 9/30
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.376E-02
0.200 1.831E-02
0.100 2.264E-02
0.040 2.869E-02
0.020 3.462E-02
0.010 4.379E-02
0.005 5.074E-02
0.002 5.996E-02
********** Link: O2-CB11 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.311E-02
0.200 3.052E-02
0.100 3.786E-02
0.040 4.841E-02
0.020 5.772E-02
0.010 7.298E-02
0.005 8.457E-02
0.002 9.995E-02
********** Link: O2-CB11 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 5.322E-06
0.200 7.890E-06
0.100 9.850E-06
0.040 1.185E-02
0.020 1.505E-02
0.010 2.981E-02
0.005 3.509E-02
0.002 4.172E-02
********** Link: CB09-CB04 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.440E-02
0.200 1.931E-02
0.100 2.528E-02
0.040 4.068E-02
0.020 4.901E-02
0.010 6.646E-02
0.005 6.812E-02
0.002 6.991E-02
********** Link: CB09-CB04 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.198E-06
0.200 1.953E-06
0.100 2.694E-06
0.040 3.671E-06
0.020 4.763E-06
0.010 8.919E-06
0.005 1.553E-02
0.002 3.646E-02
********** Link: O3-CB09 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 5.293E-03
0.200 8.091E-03
0.100 1.429E-02
0.040 3.414E-02
0.020 4.663E-02
0.010 7.239E-02
0.005 7.688E-02
0.002 8.209E-02
********** Link: O3-CB09 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.119E-06
0.200 3.512E-06
0.100 4.675E-06
0.040 8.420E-06
0.020 1.545E-02
0.010 6.354E-02
0.005 7.165E-02
0.002 8.137E-02
********** Link: IT CB14 - CB12 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 8.079E-08
0.200 1.379E-07
0.100 1.393E-06
0.040 4.882E-06
0.020 1.213E-02
0.010 7.591E-02
0.005 8.546E-02
0.002 9.675E-02
********** Link: IT CB14 - CB12 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.604E-11
0.200 4.343E-11
0.100 4.833E-10
0.040 1.817E-09
0.020 2.139E-03
0.010 7.365E-02
0.005 8.386E-02
0.002 9.506E-02
********** Link: IT CB09 - IT CB08 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.308E-02
0.200 4.399E-02
0.100 5.688E-02
0.040 7.499E-02
0.020 0.103
0.010 0.105
0.005 0.119
0.002 0.139
********** Link: IT CB09 - IT CB08 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.943E-06
0.200 1.827E-02
0.100 2.637E-02
0.040 4.803E-02
0.020 6.797E-02
0.010 8.613E-02
0.005 9.325E-02
0.002 0.102
********** Link: IT CB07 - CB12 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.578E-02
0.200 5.421E-02
0.100 6.790E-02
0.040 9.897E-02
0.020 0.136
0.010 0.163
0.005 0.174
0.002 0.188
********** Link: IT CB07 - CB12 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.675E-06
0.200 7.498E-06
0.100 2.126E-02
0.040 3.677E-02
0.020 4.971E-02
0.010 0.133
0.005 0.154
0.002 0.180
********** Link: IT CB06 - CB06 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.544E-04
0.200 6.021E-04
0.100 2.465E-03
0.040 8.739E-03
0.020 1.202E-02
0.010 1.919E-02
0.005 2.066E-02
0.002 2.242E-02
********** Link: IT CB06 - CB06 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.638E-09
0.200 5.608E-09
0.100 2.472E-08
0.040 1.747E-07
0.020 3.965E-07
0.010 1.263E-06
0.005 1.871E-06
0.002 2.665E-06
********** Link: IT CB03 - IT CB02 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.314E-02
0.200 3.107E-02
0.100 3.898E-02
0.040 5.286E-02
0.020 6.014E-02
0.010 7.298E-02
0.005 8.459E-02
0.002 9.999E-02
********** Link: IT CB03 - IT CB02 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.791E-06
0.200 7.089E-06
0.100 9.061E-06
0.040 7.879E-03
0.020 1.493E-02
0.010 3.633E-02
0.005 4.252E-02
0.002 5.016E-02
********** Link: IT CB01 - CB04 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.791E-06
0.200 7.089E-06
0.100 9.061E-06
0.040 7.879E-03
0.020 1.493E-02
0.010 3.633E-02
0.005 4.252E-02
0.002 5.016E-02
********** Link: IT CB01 - CB04 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.016E-10
0.200 1.505E-10
0.100 1.919E-10
0.040 3.690E-07
0.020 2.315E-06
0.010 3.791E-06
0.005 4.586E-06
0.002 5.636E-06
********** Link: CB02 - CB01 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.596E-03
0.200 1.287E-02
0.100 1.676E-02
0.040 2.673E-02
0.020 3.177E-02
0.010 4.012E-02
0.005 4.082E-02
0.002 4.162E-02
********** Link: CB02 - CB01 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 7.173E-06
0.200 1.175E-03
0.100 5.838E-03
0.040 1.349E-02
0.020 2.275E-02
0.010 3.392E-02
0.005 3.810E-02
0.002 4.346E-02
********** Link: CB01 - O8 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.945E-03
0.200 7.068E-03
0.100 9.591E-03
0.040 1.639E-02
0.020 2.100E-02
0.010 3.146E-02
0.005 3.281E-02
0.002 3.426E-02
********** Link: CB01 - O8 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.674E-06
0.200 5.504E-06
0.100 7.223E-06
0.040 2.875E-04
0.020 2.865E-03
0.010 4.442E-03
0.005 1.994E-02
0.002 4.080E-02
********** Link: Filter Strip ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.252
0.200 0.374
0.100 0.493
0.040 0.644
0.020 0.819
0.010 1.066
0.005 1.250
0.002 1.494
********** Link: Filter Strip ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.452E-02
0.200 0.140
0.100 0.185
0.040 0.239
0.020 0.297
0.010 0.387
0.005 0.452
0.002 0.539
********** Link: WEST ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.727E-05
0.200 8.030E-05
0.100 3.287E-04
0.040 1.165E-03
0.020 1.602E-03
0.010 2.558E-03
0.005 2.759E-03
0.002 3.000E-03
********** Link: WEST ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.157E-05
0.200 4.646E-05
0.100 2.091E-04
0.040 8.142E-04
0.020 1.154E-03
0.010 2.015E-03
0.005 2.070E-03
0.002 2.117E-03
********** Link: NORTH ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.129
0.200 0.226
0.100 0.303
0.040 0.425
0.020 0.496
0.010 0.661
0.005 0.749
0.002 0.866
********** Link: NORTH ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.114
0.200 0.187
0.100 0.239
0.040 0.301
0.020 0.401
0.010 0.467
0.005 0.563
0.002 0.691
********** Link: IT CB05 - CB06 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.362E-04
0.200 4.014E-04
0.100 1.643E-03
0.040 5.826E-03
0.020 8.010E-03
0.010 1.279E-02
0.005 1.377E-02
0.002 1.495E-02
********** Link: IT CB05 - CB06 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 5.188E-09
0.200 7.980E-09
0.100 3.519E-08
0.040 3.111E-07
0.020 6.869E-07
0.010 2.071E-06
0.005 3.068E-06
0.002 4.374E-06
********** Link: IT CB05-CB06 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 6.652E-06
0.200 9.768E-06
0.100 2.989E-02
0.040 5.088E-02
0.020 6.380E-02
0.010 8.594E-02
0.005 9.746E-02
0.002 0.112
********** Link: IT CB05-CB06 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.894E-10
0.200 2.782E-10
0.100 7.053E-06
0.040 2.796E-02
0.020 4.015E-02
0.010 7.998E-02
0.005 9.203E-02
0.002 0.107
********** Link: IT CB15 - IT CB14 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 1.559E-03
0.200 2.649E-03
0.100 1.084E-02
0.040 3.845E-02
0.020 5.287E-02
0.010 8.442E-02
0.005 9.090E-02
0.002 9.865E-02
********** Link: IT CB15 - IT CB14 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 8.079E-08
0.200 1.379E-07
0.100 1.393E-06
0.040 4.882E-06
0.020 1.213E-02
0.010 7.591E-02
0.005 8.546E-02
0.002 9.675E-02
********** Link: O5 - CB02 ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.107
0.200 0.156
0.100 0.206
0.040 0.267
0.020 0.332
0.010 0.430
0.005 0.498
0.002 0.589
********** Link: O5 - CB02 ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 6.927E-02
0.200 0.136
0.100 0.183
0.040 0.253
0.020 0.318
0.010 0.420
0.005 0.489
0.002 0.580
********** Link: Bio Retention Pond ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 6.151E-02
0.200 8.469E-02
0.100 0.109
0.040 0.153
0.020 0.206
0.010 0.505
0.005 0.579
0.002 0.668
********** Link: Bio Retention Pond ********** Link Outflow 1 Frequency
Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 9.344E-08
0.200 1.280E-07
0.100 2.001E-07
0.040 8.729E-07
0.020 1.817E-06
0.010 8.543E-06
0.005 9.216E-06
0.002 9.869E-06
********** Link: IT Filter Strip ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.359
0.200 0.482
0.100 0.594
0.040 0.745
0.020 0.921
0.010 1.168
0.005 1.353
0.002 1.598
********** Link: IT Filter Strip ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 0.252
0.200 0.374
0.100 0.493
0.040 0.644
0.020 0.819
0.010 1.066
0.005 1.250
0.002 1.494
********** Link: Playground (B18) ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 6.855E-02
0.200 9.155E-02
0.100 0.113
0.040 0.142
0.020 0.173
0.010 0.219
0.005 0.254
0.002 0.300
********** Link: Playground (B18) ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 6.652E-06
0.200 9.768E-06
0.100 2.989E-02
0.040 5.088E-02
0.020 6.380E-02
0.010 8.594E-02
0.005 9.746E-02
0.002 0.112
********** Link: B11 OPEN CHANNEL ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.811E-03
0.200 6.436E-03
0.100 8.630E-03
0.040 1.356E-02
0.020 1.709E-02
0.010 2.383E-02
0.005 2.454E-02
0.002 2.529E-02
********** Link: B11 OPEN CHANNEL ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.316E-03
0.200 4.524E-03
0.100 6.150E-03
0.040 1.037E-02
0.020 1.291E-02
0.010 1.809E-02
0.005 1.948E-02
0.002 2.116E-02
********** Link: B25 OPEN CHANNEL ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.252E-04
0.200 7.225E-04
0.100 2.957E-03
0.040 1.049E-02
0.020 1.442E-02
0.010 2.302E-02
0.005 2.479E-02
0.002 2.690E-02
********** Link: B25 OPEN CHANNEL ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 2.524E-04
0.200 3.883E-04
0.100 1.914E-03
0.040 8.631E-03
0.020 1.159E-02
0.010 2.072E-02
0.005 2.123E-02
0.002 2.163E-02
********** Link: B28 OPEN CHANNEL ********** Link Inflow Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 4.773E-03
0.200 6.435E-03
0.100 8.377E-03
0.040 1.213E-02
0.020 1.568E-02
0.010 1.771E-02
0.005 1.797E-02
0.002 1.831E-02
********** Link: B28 OPEN CHANNEL ********** Link Outflow 1 Frequency Stats
Season: 10/1 - 9/30 **********
Flood Frequency Data(cfs)
(Exceedance Probability Computed Using Gringorten Plotting Position)
Annual
Exceedance
Probability Flood Peak (cfs)
======================================
0.500 3.934E-03
0.200 5.346E-03
0.100 7.085E-03
0.040 1.038E-02
0.020 1.370E-02
0.010 1.575E-02
0.005 1.609E-02
0.002 1.652E-02
PHILLIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 20
Appendix F – Conveyance Calculations
Project:
Sheet Number:Of:
Calculated by:Date:
Checked by:Date:
Conveyance Analysis - Beacon Way S Parking Lot
1) Rational Method - Computing Runoff
Formulas:
Rational Method:
Q = CIA
I = m/Tc^n
Where:
Q = Runoff in CFS
I = Intensity (in/hr)
C = Runoff coefficient (0.9 for aspahlt, 0.15 for landscape)
A = Area (Acres)
m = Rainfall Coefficients (MRI); 6.89 for the 25-year event
n = Rainfall Coefficients (MRI); 0.539 for the 25-year event
Tc = Time of Concentration (Minutes)
2) Sub-Basin Collection Locations
CB 15 Collects runoff from sub-basin B24
CB 14 Collects runoff from sub-basin B23 and CB 15
CB 13 Collects runoff from sub-basins B27 and B23 and from CB 14
Background: The Beacon Way S Parking Lot conveyance system is a newproposed tightline conveyance
system that discharges to a dispersion trench. The purpose of this analysis is to determine the conveyance
capacity of the system during the 25-year storm event.
Subbasins B23, B24, B27 and B33 contribute runoff to the parking lot conveyance system.
Basin maps can be found in the Appendicies of the TIR. The 25-year storm event was used to
calculate runoff. The time of conentration was assumed to be 5 minutes to be conservative.
Sub-Basin Impervious Area (AC) Pervious Area (AC) Composite C
B23
B24
B27
B33
0.36
0.17
0.23
0.1
0.06
0.12
0.06
0.14
0.79285714
0.58965517
0.74482759
0.4625
I Q
2.89384
2.89384
2.89384
2.89384
0.96365
0.49485
0.62507
0.32122
194072 - Phillip Arnold Park
4 4
CWC 10/24/21
NOTES & REFERENCES
Computational Methods
WSDOT Hydraulics Manual
Chapter 6
WSDOT Hydraulics Manual
Equation 6-4
n =0.012, per Civil Engineering
Reference Manual, App 19.A
Flow Calculated using Rational
Method - See Attached
1736 Fourth Avenue S, Suite A
Seattle, Washington 98134
phone 206.624.1387
fax 206.624.1388
1
Project:
Sheet Number:Of:
Calculated by:Date:
Checked by:Date:
3) Headloss Computation
WSEL @ CB 13:
WSEL@ CB 13 = WSEL + Friction Losses from Dispersion Trench to CB 13.
Pipe Head Loss (Friction):
Pipe SD-13:
Head Loss (Junctions)
Entrance Loss at CB13
Exit Loss at CB13
Total Exit Losses =
WSEL @ CB13 = hf+Entrance and Exit Losses WSEL@ Dispersion Trench:
CB 13 Rim:
12Pipe Diameter, d =
393.32
The water surface elevation (WSEL) at the dsicahrge point (dispersion trench) will be set by
the notched weir. The elevation of the notched weir is assumed to be elevation 393'
PASS
hm.exit =(v^2)= 0.0734g
0.146
3.06 fps
Area, A = 0.79 sf Flow, Q = 2.40478 cfs
Pipe Flow Velocity, V=in
hm.exit =(v^2)= 0.0734g
0.077D2.667
393.22
hm.exit =(v^2)
4g
Length, L = 20 lf
hf = ^2 x
2.15(Q)(n)
L =
Pipe Diameter, d = 12 in Pipe Flow Velocity, V=
2.15(Q)(n)hf = ^2
3.06 fps
Area, A = 0.79 sf Flow, Q = 2.40478 cfs
Pipe Diameter, d = 12 in Area, A = 0.79 sf
x LD2.667
Flow, Q = 2.40478 cfs Hydraulic Radius, R = 0.25 ft
Manning's Coef., n = 0.012 Wetted Perimeter 3.14 ft
194072 - Phillip Arnold Park
4 4
CWC 10/24/21
NOTES & REFERENCES
WSDOT Hydraulics Manual
Equation 6-5
1736 Fourth Avenue S, Suite A
Seattle, Washington 98134
phone 206.624.1387
fax 206.624.1388
2
Project:
Sheet Number:Of:
Calculated by:Date:
Checked by:Date:
WSEL @ CB 14:
Pipe Head Loss (Friction):
Pipe SD-14:
Head Loss (Junctions)
Entrance Loss at CB14
Exit Loss at CB14
Total Exit Losses =
WSEL @ CB14 = hf+Entrance and Exit Losses WSEL@ Dispersion Trench:
CB 14 Rim:
393.49
397.53
PASS
WSEL@ CB 14 = WSEL @ CB13 + Friction Losses in pipe SD-14 and Junction losses at CB
14.
hm.exit =(v^2)= 0.0274g
0.054
1.86 fps
Area, A = 0.79 sf Flow, Q = 1.458495 cfs
hm.exit =(v^2)= 0.0274g
Pipe Diameter, d = 12 in Pipe Flow Velocity, V=
1.86 fps
Area, A = 0.79 sf Flow, Q = 1.458495 cfs
4g
Pipe Diameter, d = 12 in Pipe Flow Velocity, V=
x L = 0.214D2.667
Length, L = 151 lf
hf = 2.15(Q)(n)^2
Manning's Coef., n = 0.012 Wetted Perimeter 3.14 ft
Flow, Q = 1.458495 cfs Hydraulic Radius, R = 0.25 ft
Pipe Diameter, d = 12 in Area, A = 0.79 sf
hf = 2.15(Q)(n)^2 x LD2.667
194072 - Phillip Arnold Park
4 4
CWC 10/24/21
NOTES & REFERENCES
WSDOT Hydraulics Manual
Equation 6-5
hm.exit =(v^2)
1736 Fourth Avenue S, Suite A
Seattle, Washington 98134
phone 206.624.1387
fax 206.624.1388
3
Project:
Sheet Number:Of:
Calculated by:Date:
Checked by:Date:
WSEL @ CB 14:
Pipe Head Loss (Friction):
Pipe SD-14:
Head Loss (Junctions)
Entrance Loss at CB14
Exit Loss at CB14
Total Exit Losses =
WSEL @ CB15 = hf+Entrance and Exit Losses WSEL@ Dispersion Trench:
CB 14 Rim:
393.52
399.93
PASS
WSEL@ CB 15 = WSEL @ CB14 + Friction Losses in pipe SD-15 and Junction losses
at CB 15.
hm.exit =(v^2)= 0.0034g
0.006
0.63 fps
Area, A = 0.79 sf Flow, Q = 0.494846 cfs
hm.exit =(v^2)= 0.0034g
Pipe Diameter, d = 12 in Pipe Flow Velocity, V=
fps
Area, A = 0.79 sf Flow, Q = 0.494846 cfs
4g
Pipe Diameter, d = 12 in Pipe Flow Velocity, V=0.63
hf = 2.15(Q)(n)^2 x LD2.667
Pipe Diameter, d = 12 in Area, A = 0.79 sf
Flow, Q = 0.494846 cfs Hydraulic Radius, R = 0.25 ft
Manning's Coef., n = 0.012 Wetted Perimeter 3.14 ft
Length, L = 150 lf
hf = 2.15(Q)(n)^2 x L = 0.024D2.667
hm.exit =(v^2)
194072 - Phillip Arnold Park
4 4
NOTES & REFERENCES
CWC 10/24/21
1736 Fourth Avenue S, Suite A
Seattle, Washington 98134
phone 206.624.1387
fax 206.624.1388
Project:
Sheet Number:Of:
Calculated by:Date:
Checked by:Date:
Conveyance Analysis - Jones Ave S Open Channel
Background: The eastern drive lane of Jones Ave S sheet flows to an existing grass lined open channel along the
western perimeter of the park. The proposed development will construct a new curb and gutter along Jones Ave S and
construct curb cuts for runoff to drain into the ditch. The proposed ditch sections are shown below; the projet is not
significantly modifying the geometry of the existing ditch, nor is it adding PGIS surface to Jones Ave. The Purpose of
this analysis is to prove that the ditch as sufficient capacity to convey runoff.
194072 - Phillip Arnold Park
1 3
CWC 10/24/21
NOTES & REFERENCES
Computational Methods
WSDOT Hydraulics Manual
Chapter 6
WSDOT Hydraulics Manual
Equation 6-4
n =0.012, per Civil Engineering
Reference Manual, App 19.A
Flow Calculated using Rational
Method - See Attached
1736 Fourth Avenue S, Suite A
Seattle, Washington 98134
phone 206.624.1387
fax 206.624.1388
Project:
Sheet Number:Of:
Calculated by:Date:
Checked by:Date:
Input Summary:
Item
Section Type
Side Slope
Channel Depth
Manning’s “n”
Rational Method Inputs
Contributing Area (Pavement)
0.03
Longitudinal Slope
Input
V-Channel
3H:1V or 4H:1V
1.30-feet
2.75%
0.17 Acres
100 Year:
m: 8.75
n: 0.5454
Q: 0.57 CFS
Tc: 5min
194072 - Phillip Arnold Park
2 3
CWC 10/24/21
NOTES & REFERENCES
WSDOT Hydraulics Manual
Equation 6-5
1736 Fourth Avenue S, Suite A
Seattle, Washington 98134
phone 206.624.1387
fax 206.624.1388
Project:
Sheet Number:Of:
Calculated by:Date:
Checked by:Date:
HYDRAFLOW PRINTOUT:
194072 - Phillip Arnold Park
3 3
CWC 10/24/21
1736 Fourth Avenue S, Suite A
Seattle, Washington 98134
phone 206.624.1387
fax 206.624.1388
PHILLIP ARNOLD PARK ISSUED FOR PERMIT - DRAINAGE REPORT
CITY OF RENTON PND No. 194072
Issued for Permit - 21
Appendix G – Geotech Report
GEOTECHNICAL ENGINEERING REPORT
PHILIP ARNOLD PARK IMPROVEMENTS
720 Jones Avenue South
Renton, Washington
Project No. 2294.01
27 October 2020
Prepared for:
City of Renton Parks Department and
Hough Beck & Baird, Inc.
Prepared by:
Geoprofessional Consultants
19019 36th Avenue W., Suite E
Lynnwood, WA 98036
TABLE OF CONTENTS
INTRODUCTION .................................................................................................................................1
PROJECT INFORMATION .....................................................................................................................1
Site Location ..................................................................................................................................1
Project Description .........................................................................................................................1
SITE HISTORY .....................................................................................................................................2
SITE CONDITIONS ...............................................................................................................................2
Surface Conditions .........................................................................................................................2
Subsurface Conditions ....................................................................................................................3
Groundwater .................................................................................................................................5
CONCLUSIONS AND RECOMMENDATIONS ..........................................................................................5
General Geotechnical Considerations ..............................................................................................5
Geologically Hazardous Areas .........................................................................................................6
Earthwork ......................................................................................................................................9
Site Preparation .............................................................................................................................9
Structural Fill Placement and Compaction ..................................................................................... 11
Utility Installation Recommendations ........................................................................................... 13
Shallow Foundation Design Recommendations and Considerations ............................................... 14
Retaining Walls ............................................................................................................................ 16
Light Pole Foundations ................................................................................................................. 17
Seismic Design Parameters ........................................................................................................... 17
Stormwater Infiltration Considerations ......................................................................................... 18
Erosion Control ............................................................................................................................ 21
Pavement ........................................................................................................................................ 21
CLOSURE .......................................................................................................................................... 22
FIGURES
Figure 1 – Site and Exploration Plan
APPENDICES
Appendix A – Subsurface Exploration Procedures and Logs
Appendix B – Laboratory Testing Procedures and Results
Page | 1
GEOTECHNICAL ENGINEERING REPORT
PHILIP ARNOLD PARK IMPROVEMENTS
720 JONES AVENUE SOUTH
RENTON, WASHINGTON
Project No. 2294.01
27 October 2020
INTRODUCTION
This geotechnical engineering exploration and analysis has been completed for the proposed improvements
at Philip Arnold Park in Renton, Washington. Seven borings and three test pit/infiltration test explorations
were completed to depths ranging from approximately 3.5 feet to 11.5 feet below the existing ground surface
to evaluate subsurface conditions. Three shallow hand auger borings were also completed extending to
depths of about six inches for the purpose of determining stripping depths near proposed basketball court
improvements. Descriptive logs of the explorations are included in Appendix A and Appendix B contains a
summary of laboratory testing procedures and results.
PROJECT INFORMATION
Site Location
The project site (Phillip Arnold Park) comprises two adjoining parcels (King County Parcel Nos. 202305-
9059 and 00072-0175) atop historic Renton Hill at 720 Jones Avenue South in Renton, Washington. The
site is located directly southeast of the Beacon Way South and Jones Avenue South intersection. The
triangular-shaped property encompasses 10.71 acres and is bordered by Jones Avenue South to the west,
Beacon Way South to the northeast, and by Puget Sound Energy powerline easements and undeveloped
land to the southeast. The project site is illustrated on the Site and Exploration Plan, Figure 1.
Project Description
Plans available at the time this report was prepared indicate that several improvements are proposed in
the western half of the property. Site improvements are expected to include:
• Looped ADA accessible walkways throughout the western site area and the possible installation
of two culverts below the proposed walkway;
• A short pedestrian bridge along the new trail as an alternative to the culverts;
• Several new retaining walls which are expected to be 2.25 feet tall in exposed height or less;
• Removal of the existing activity building and replacement with parent plaza, shelter, and Portland
loo restroom;
• Playground replacement;
Philip Arnold Park Improvements
Project 2294.01
27 October 2020
Page | 2
• Basketball court renovation and installation of terraced seating;
• Parking lot pavement repairs;
• New park signage and new or relocated light poles, and;
• Upgraded utility services and improved site drainage and stormwater management including
infiltration features.
SITE HISTORY
The property was clear cut as part of initial park development and based on site topography, the site
appears to have been graded by performing cuts in the eastern site area and grading material toward the
west. The presence of fill material in the western site area was evidenced by fills up to approximately 4.5
feet deep encountered within two of our borings (B-1 and B-4).
The surrounding historic Renton Hill area supported coal mining operations and the main portal led to
associated shafts and adits extending below the park. The historic Renton hill coals were first discovered
in 1873, and coal mines were operated until 1920, resulting in 1.3 million tons of coal removed. As a result
of coal mining operations in the area, the site is located within a “moderate” coal mine hazard as defined
by the City of Renton. Further discussion regarding the associated coal mine hazard can be found in the
Geologically Hazardous Areas section of this report.
SITE CONDITIONS
Surface Conditions
The subject site includes irregular inclinations across the site ranging from relatively level conditions to
slopes inclined as high as 50 percent. The property includes approximately 63 feet of total elevation
change grading from about 436 feet in the eastern site margin to about 373 feet in the northwestern site
margin. The baseball field and surroundings in the east-central site area includes relatively level
conditions. Site topography west and southwest of the baseball field is relatively gentle ranging from
inclinations of about 3 percent to 26 percent, with the steepest slopes west of the baseball field being
located west and southwest of the existing playground. Site topography east and southeast of the baseball
field includes steeper slopes ranging from inclinations of about 26 to 50 percent. Some of the site slopes
are mapped by the City of Renton as meeting the City definition for regulated steep slopes and landslide
hazard areas; further discussion regarding site slopes can be found in the Geologically Hazardous Areas
section of this report.
The site surface is primarily covered by landscaped grass, with some brambles surrounding the existing
basketball court and northwestern park sign, and deciduous trees scattered across the western half of the
property. Existing trees on the property will remain in place as part of proposed improvements.
The site includes two asphalt paved parking lots, the main parking lot being located in the northern site
area with ingress and egress provided by Beacon Way South. A smaller four-vehicle hammerhead-shaped
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asphalt paved parking lot is located in the west-central site area with ingress and egress provided by Jones
Avenue South.
The site also includes areas with concrete walkways extending from the main parking lot to the existing
activity building and playground, an asphalted basketball court, an asphalted tennis court, imported sand
material surfacing the baseball infield, and an existing playground surfaced with engineered wood fiber.
Subsurface Conditions
Local Geologic Conditions
The publication Geologic Map of the Renton Quadrangle, King County, Washington (USGS, GQ 405, 1965)
indicates that the subject site has been mapped as containing glacially consolidated ground moraine
deposits (Qgt) in the northern and eastern site areas, with recessional stratified kame deposits (Qik)
mapped in the central and western site areas. The ground moraine deposits are otherwise known as
glacial till, which are glacially consolidated and heterogenous soils consisting of a mixture of clay, silt, sand,
gravel, cobbles, and boulders in varying amounts. Glacial till is colloquially termed “hardpan” in western
Washington due to its compact and dense nature resulting from the deposit forming below the
overburden of historical glaciers. As a result of the soil density and high fines content, such deposits
typically include very low permeability potential. The recessional stratified kame deposits are outwash
sands consisting of pebbly sand and gravels which were deposited in high energy glaciofluvial
environments as the historic Puget glacial lobe receded. Granular outwash soils may have a relatively
high permeability due to their low fines content (the soil fraction passing the US No. 200 sieve). Such
deposits are major sources of construction materials in the Renton uplands east of the Green River Valley.
The above-referenced map delineates an irregular contact between the glacial till and recessional kame
deposits; in general the recessional kame deposits are mapped in the central and western site areas,
including the majority of the baseball field, playground area, and tennis courts. Glacial till is mapped in
the northern and eastern site areas including the areas east of the baseball field, the basketball court,
northern parking lot, and existing activity building.
We completed seven borings to approximately 11.5 feet, and three test pits between approximately 3.5
and 5 feet to characterize subsurface conditions on the property. Subsurface conditions disclosed by the
borings and test pits are generally consistent with the published mapping, except outwash sands were
encountered at the locations of B-4, B-5, B-6, and TP-2/IT-2, indicating that outwash sand and gravel
deposits extend further north than depicted on the published geologic mapping. The outwash sands are
a younger soil unit than the glacial till. Glacial till was not encountered in our explorations except for TP-
1/IT-1 and B-7 which were completed in the northeastern site area by the park sign. Seven of our
explorations also disclosed a limited amount of undocumented fill material above the native soils at the
subject site.
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The soil descriptions presented below have been generalized for ease of report interpretation. Please
refer to the exploration logs in Appendix A for detailed soil descriptions at the exploration locations.
Variations in subsurface conditions may exist between the exploration locations and the nature and extent
of variations between the explorations may not become evident until additional explorations are
completed or until construction. Subsurface conditions at specific locations are summarized below.
Fill: Seven of the borings and test pits disclosed undocumented fill material to depths of approximately
1.5 to 4.5 feet extending below the ground surface. Topsoil was not directly observed below sod, the
likely result of previous stripping during initial park development. In particular, the deepest fills were
encountered at the locations of borings B-1 and B-4. The fill material typically consisted of loose, moist,
brown, silty sand some gravel, with fine organic material, thin roots, and scattered materials such as glass,
concrete, and wood fragments, the origin of which is unknown. It should be noted that the composition
and depth of uncontrolled fill material may vary over relatively short distances. The following table
provides approximate depths and fill materials encountered at exploration locations:
Summary of Fill Material Observations
Exploration Approximate
depth of fill (feet)
Fill material description
B-1 4.5 Silty SAND some gravel, thin root intrusions, wood fragments
B-2 1.5 Silty SAND some gravel, thin root intrusions
B-3 1.5 Silty SAND some gravel, thin root intrusions
B-4 4.5 Silty SAND some gravel, thin root intrusions
B-7 1.5 Silty SAND some gravel, thin root intrusions
TP-1/IT-1 1.5 Silty SAND gravel, thin root intrusions, concrete and wood
fragments
TP-3/IT-3 2.5 SAND with silt and gravel, thin root intrusions, trace organics,
glass fragments
Outwash Deposits: Outwash soils were encountered at every exploration location besides B-7 and
TP-1/IT-1, which were conducted in the north site corner. Such soils were encountered to the terminus
of each exploration below fill material where present. The outwash typically consisted of medium dense
to dense, moist, brown, sand with varying amounts of silt and gravel. Based on the low fines content of
these soils and our in situ infiltration testing, the outwash has a moderate permeability.
Glacial Till: Glacial till was only encountered in explorations TP-1/IT-1 and B-7, which were conducted in
the northwestern site corner by the existing park sign. Glacial till was encountered below fill material at
the exploration locations and extended to the terminus of exploration. The glacial till consisted of medium
dense to dense, brownish gray, silty sand with gravel including weak cementation and light soil mottling
throughout. Glacial till is located stratigraphically below the outwash sand deposits.
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Groundwater
Groundwater was observed while drilling two of the seven borings (B-2 and B-6). We observed
groundwater at a depth of about 6.5 feet below existing grades while advancing B-2 and at a depth of
about 9 feet below existing grades while advancing B-6. The groundwater was encountered within the
relatively permeable outwash soils. Groundwater was not encountered within the lowest elevation boring
B-7 where impermeable glacial till soils were encountered. Because the outwash is stratigraphy above the
glacial till soils, the groundwater encountered during exploration is interpreted to represent a perched
groundwater condition which may be occurring within the permeable sands due to the presence of
hydraulically restrictive soils at greater depth.
Based on our review of the Department of Ecology’s well report map, it does not appear that active public
or private wells are located within one-quarter mile of the property.
It should be noted that groundwater conditions will likely vary seasonally and in response to precipitation
events, land use, and other factors, and its occurrence will be influenced by the composition and
density/consistency of native material, in particular. In general, seasonal high groundwater in western
Washington occurs toward the end of the local wet season, typically around the end of May. Groundwater
will also be influenced by landscape irrigation which was occurring at the time the field exploration took
place.
CONCLUSIONS AND RECOMMENDATIONS
General Geotechnical Considerations
Based on information gathered during the field exploration, laboratory testing, and analysis, we conclude
that construction of the proposed improvements is feasible from a geotechnical perspective provided
that the recommendations presented herein are followed during design and construction. Selected
aspects of the site conditions that should be considered during design and construction are summarized
below.
• The relatively clean nature of the native outwash sand soils may be considered favorable from
the stormwater management perspective in that the soils have a moderate permeability.
• Existing grass and sod should be stripped below proposed improvements, as well as loose or
unsuitable fills encountered during grading.
• It will be feasible to use the native granular outwash soils with a low fines content as structural
fill, negating the need to import these materials. Glacial till may be used as structural fill, although
the material should be considered highly moisture-sensitive.
• Some of the existing fill material and the native glacial till has a relatively high fines content and
should be considered highly moisture sensitive. Attempting to grade soils with a high fines
content will be difficult, if not impossible, during wet weather.
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Geotechnical engineering recommendations for site grading, drainage, foundations, and other
geotechnically-related aspects of the project are presented in the following sections. The
recommendations contained in this report are based upon the results of and the field exploration,
laboratory testing, engineering analyses, review of historical documents, and our current understanding
of the proposed project design. ASTM and WSDOT specification codes cited herein refer to the current
manual published by the American Society for Testing & Materials and the 2018 edition of the WSDOT
Standard Specifications for Road, Bridge, and Municipal Construction (Publication M41-10).
Geologically Hazardous Areas
In general accordance with Chapter 4-3-050E.1 of the Renton Municipal Code (RMC), we utilized existing
site plans, City maps, and online mapping applications to determine the presence of regulated geologically
hazardous areas in the project vicinity. The maps are utilized as a general guide and the actual presence
or absence and classification of critical areas on a specified site is determined in the field by qualified
consultants. Our conclusions regarding geologically relevant hazardous areas are presented below, with
italics indicating code definitions and our response:
Steep Slopes Areas
The City of Renton characterizes regulated steep slope areas into two categories, sensitive slopes and
protected slopes. These categories are defined in the RMC as shown below:
• Sensitive Slopes: A hillside, or portion thereof, characterized by:
(a) an average slope of twenty five percent to less than forty percent as identified in the City of
Renton Steep Slope Atlas or in a method approved by the City;
(b) an average slope of forty percent or greater with a vertical rise of less than fifteen feet as
identified in the City of Renton Steep Slope Atlas or in a method approved by the City, or;
(c) abutting an average slope of twenty five percent to forty percent as identified in the City of
Renton Steep Slope Atlas or in a method approved by the City. This definition excludes engineered
retaining walls.
• Protected Slopes: A hillside, or portion thereof, characterized by an average slope of forty percent
or greater grade and having a minimum vertical rise of fifteen feet as identified in the City of
Renton Steep Slope Atlas or in a method approved by the City.
Based on our review of City mapping, several areas on the site are mapped as including steep slope areas.
In particular, the slope complex south/southwest of the existing playground and east/southeast of the
baseball field are mapped as regulated slopes.
Based on our review of site topography, the slopes south/southwest of the existing playground area
include average slopes of approximately 26 percent with vertical rise up to approximately 14 feet, but the
majority of the slope includes 10 feet or less of total vertical rise. As such, the slope complex meets criteria
A for sensitive slopes due to including average slopes of 25 percent to less than 40 percent. In accordance
with RMC 4-5-050.G.2, sensitive slope do not include mandated buffers and the buffers and setbacks are
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determined based upon the results of a geotechnical report. Proposed improvements near the slope
includes a reflexology path offset approximately 15 feet from the top of slope, a concrete pathway
extending through the slope complex, two culverts below the proposed concrete pathway or a small
pedestrian bridge in lieu of culverts, and retaining walls approximately 2 or less feet in exposed vertical
height. The proposed improvements will require removal of grass and sod, limited excavation to establish
grades, and shallow fills to establish final grades.
Two retaining walls are proposed within the south/southwestern steep slope complex. One retaining wall
is proposed north of the existing tennis court, the other retaining wall located north of the hammerhead
parking lot adjacent to Jones Avenue South. Both retaining walls are positioned along the downgradient
side of the proposed concrete pathway and will likely require shallow cuts followed by backfill behind the
walls to establish grades for the concrete pathway. Both walls will be 2 or less feet in exposed vertical
height and include some embedment. Two culverts are proposed below the concrete pathway in
proximity to the mentioned retaining walls. The culverts are positioned on or near the steep slope
complex. The culverts will likely require shallow cuts to prepare subgrade and fills along the exterior to
establish final grades for the concrete pathway. If the pedestrian bridge alternative is selected, there will
be no culvert installation, just shallow foundations for the bridge.
Provided proper erosion control measures are in place during construction along the sensitive slope, it is
our opinion that the proposed construction can be undertaken safely without adversely affecting slope
stability. In accordance with RMC 4-5-050.F.2, the proposed improvements will not increase the threat of
the geologic hazard to adjacent properties, will not adversely impact other critical areas on the site, and
proposed development can be safely accommodated on the site. In accordance with RMC 4-5-050.G.5.g,
ZGA anticipates that we will provide on-site inspection during construction on or near the sensitive slope
complex.
Based on review of site topography, the slope complex east/southeast of the existing baseball field include
average slopes of approximately 34 percent with vertical rise up to approximately 16 feet, several isolated
areas include slope inclinations up to about 50 percent. As such, the slope complex meets criteria A and
C for sensitive slopes due to including average slopes of 25 percent to less than 40 percent, and including
limited steeper areas which abut slopes that average between 25 percent and 40 percent. This slope
appears to have been created via previous grading, in our opinion. The nearest proposed improvements
to the sensitive slope include parking lot pavement repairs in the limits of the northern asphalted parking
lot. The proposed work will not disturb any material along the sensitive slope and the sensitive slope area
will remain in its existing condition during and after construction. In accordance with RMC 4-5-050.F.2,
the proposed improvements will not increase the threat of the geologic hazard to adjacent properties,
will not adversely impact other critical areas, and proposed development can be safely accommodated
on the site, in our opinion.
Landslide Hazard Areas
The City of Renton characterizes landslide hazard areas into four distinct categories, as defined below:
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• Low Landslide Hazard: Areas with slopes less than fifteen percent.
• Medium Landslide Hazard: Areas with slopes between fifteen percent and forty percent and
underlain by soils that consist largely of sand, gravel or glacial till.
• High Landslide Hazards: Areas with slopes greater than forty percent, and areas with slopes
between fifteen percent and forty percent and underlain by soils consisting largely of silt and clay.
• Very High Landslide Hazards: Areas of known mapped or identified landslide
Based on our review of on-line City mapping, the slope complex east/southeast of the southeast portion
of the baseball field is mapped as including a landslide hazard. As discussed in the previous section, the
slope has average inclinations of approximately 34 percent with a vertical rise up to approximately 16
feet, with isolated areas include inclinations up to about 50 percent. Based on our subsurface exploration
and geologic mapping, the area likely includes sand, gravel, or glacial till soils. Therefore, the slopes meet
the definition of a medium landslide hazard due to including areas within slopes between 15 and 40
percent which are underlain by soils that consist of sand, gravel, or glacial till. In accordance with RMC 4-
5-050.G.2, medium landslide hazard areas do not include mandated buffers and the buffers and setbacks
are provided based upon the results of a geotechnical report. The nearest proposed improvements to the
slope include parking lot pavement repairs to the northern parking lot. The proposed work will not disturb
the landslide hazard area during construction, and the slope will remain in its current state throughout
and following construction. In accordance with RMC 4-5-050.F.2, the proposed improvements will not
increase the threat of the geologic hazard to adjacent properties, will not adversely impact other critical
areas, and proposed development can be safely accommodated on the site, in our opinion.
Coal Mine Hazard Areas
The City of Renton characterizes coal mine hazard areas into three distinct categories, as defined below:
• Low Coal Mine Hazards: Areas with no known mine workings and no predicted subsidence. While
no mines are known in these areas, undocumented mining is known to have occurred.
• Medium Coal Mine Hazards: Areas where mine workings are deeper than two hundred feet for
steeply dipping seams, or deeper than fifteen times the thickness of the seam or workings for
gently dipping seams. These areas may be affected by subsidence.
• High Coal Mine Hazard: Areas with abandoned and improperly sealed mine openings and areas
underlain by mine workings shallower than two hundred feet in depth for steeply dipping seams,
or shallower than fifteen times the thickness of the seam or workings for gently dipping seams.
These areas may be affected by collapse or other subsidence.
Based on our review of City mapping, the entirety of the subject site is mapped within a medium coal
mine hazard resulting from historical coal mine activities occurring in historic Renton hill. Based on our
review of coal mine mapping of historic Renton Hill, the subject site is located approximately 2,150 feet
east of the main coal mine entry near what is now I-405. The main slope extends at an approximate 10-
degree slope into Renton Hill. Based on the elevations of the site and the approximate elevation of the
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portal, we estimate that coal mine activities were occurring at depths of approximately 720 feet and
greater below the existing ground site surface. As such, the subject site meets the City definition for
medium coal mine hazard areas due to including mine workings deeper than fifteen times the thickness
of the seam or workings for gently dipping seams.
Given the depth of coal mine workings, it is our opinion that the risk of trough subsidence affecting the
site is low. Based on our review of LiDAR imagery utilizing the King County online iMap tool, subsidence
features such as sinkholes or ground cracking were unidentifiable on the site or surrounding area. Given
the minimal extent of site improvements, distance from coal mine workings, lack of evidence for known
coal mine workings near surface, and lightly loaded nature of improvements, it is our opinion that
mitigation for coal mine hazards is unnecessary.
In accordance with RMC 4-5-050.G.2, medium coal mine hazard areas do not include mandated buffers
and the buffers and setbacks are provided based upon the results of a geotechnical report. In accordance
with RMC 4-5-050.F.2, the proposed improvements will not increase the threat of the geologic hazard to
adjacent properties, will not adversely impact other critical areas, and proposed development can be
safely accommodated on the site, in our opinion. In accordance with RMC 4-5-050.G.5.i.ii, any coal mine
hazards found during any development activities shall be immediately reported and coal mine hazards
shall be mitigated prior to recommencing reconstruction.
Earthwork
The following sections present recommendations for site preparation, subgrade preparation and
placement of engineered fills on the project. The recommendations presented in this report for design
and construction of foundations and slabs are contingent upon following the recommendations outlined
in this section.
Earthwork on the project should be observed and evaluated by a ZGA representative. Evaluation of
earthwork should include observation and testing of structural fill, subgrade preparation, foundation
bearing soils, and subsurface drainage installations.
Site Preparation
Existing Structure Removal: The site includes a community center and restroom building which will be
demolished. We recommend that any existing foundation elements or other below grade structures that
may be present be removed from the building footprint. Void spaces remaining from demolition and
foundation element removal should be filled in accordance with the recommendations in the Structural
Fill Placement and Compaction section of this report.
Stripping: In preparation for grading we recommend removal of all existing surficial vegetation (brambles
and grasses) from the limits of proposed improvements. Based on our subsurface exploration, we
estimate that grass and sod stripping will be limited to approximately three to five inches. Our subsurface
exploration did not encounter highly organic topsoil-like material below sod, the likely result of previously
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completed stripping during initial park development. Please note that the depth of surficial organics soils
is likely to vary across the site.
As part of park improvements, the basketball court will be renovated, and nearby brambles will be
removed, and grass sod stripped. As part of our subsurface exploration we performed three hand auger
borings to determine stripping depths in the proximity of the basketball court where the scramble is
proposed. Based on our subsurface exploration, we estimate that grass and sod stripping in the area will
be limited to approximately three to five inches. Subgrades for the new bleachers planned near the
basketball court should be verified by a ZGA representative to verify that at least medium dense properly
prepared fill or native soil is present.
Existing Fill Removal: Site preparation may include selective removal of existing undocumented fill
material containing organics or deleterious debris at the proposed retaining walls, plaza, shelter, Portland
loo, pedestrian bridge foundations, and walkways. The presence and depth of fill across the site varies
from approximately 1.5 to 4.5 feet below existing grades. The fill material typically consisted of loose,
moist, brown, silty sand some gravel, with fine organic material, thin roots, and scattered materials such
as glass, concrete, and wood fragments. The deepest fills were observed at B-1 and B-4 which disclosed
fill to approximately 4.5 feet. B-1 was performed near a proposed culvert in the southern site area directly
north of the tennis courts, and B-4 was completed near the proposed plaza. As such, these areas may
require the most fill removal if necessary. A ZGA representative should verify the condition of subgrade
soils to ensure that at least medium dense properly prepared fill or native soil are present.
Variation in the fill depth and composition, and the depth of organics possibly below the fill, should be
expected. These materials should be evaluated during construction and removed as necessary under the
observation of a ZGA representative. Our representative will identify unsuitable materials that should be
removed and those that may be re-used as structural fill. The resultant excavations should be backfilled
in accordance with the subsequent recommendations for Structural Fill Placement and Compaction.
Specific recommendations regarding removal of existing fill material at foundation and slab locations are
provided subsequently in association with foundation design and construction recommendations.
Site Preparation Scheduling: We understand that construction is anticipated to begin in 2021. We
recommend that site preparation activities take place in the drier summer months if possible. Operating
wheeled and tracked equipment when the existing moisture-sensitive surficial soils are wet will result in
significant disturbance of the soil and this may require its removal and increase construction costs.
Completion of site preparation and grading under dry site and weather conditions will reduce the
potential for disturbance of the moisture-sensitive soils and reduce the likelihood of subgrade disturbance
and the need to replace disturbed soils with other granular fill material.
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Structural Fill Placement and Compaction
Construction of proposed retaining walls, pathways, culverts, and structures will require placing limited
structural fills to establish final grades. All fill material should be placed in accordance with the
recommendations herein for structural fill. Prior to placement, the surfaces to receive structural fill should
be observed by a ZGA representative to verify that at least medium dense properly prepared fill or native
soil is present. In the event that soft or loose soils are present at the subgrade elevation, the soils should
be compacted to a firm and non-yielding condition and to at least 95 percent of the modified Proctor
maximum dry density (ASTM D 1557) prior to placing structural fill. This may require partial to complete
removal of existing material and replacing it as compacted structural fill. In the event that the soil cannot
be adequately compacted, they should be removed as necessary and replaced with granular fill material
at a moisture content that allows its compaction to the recommended density.
The suitability of soil for use as structural fill depends primarily on the gradation and moisture content of
the soil when it is placed. As the amount of fines (that soil fraction passing the US No. 200 sieve) increases,
soil becomes increasingly sensitive to small changes in moisture content and adequate compaction
becomes more difficult, or impossible, to achieve. Generally, soils containing more than about 5 percent
fines by weight (based on that soil fraction passing the US No. 4 sieve) cannot be compacted to a firm,
non-yielding condition when the moisture content is more than a few percent from optimum. The
optimum moisture content is that which yields the greatest soil density under a given compactive effort.
Re-use of On-site Soils: Soils expected to be encountered in excavations across the site include native
glacial till, outwash, and existing fill material. The materials typically consist of sand with a variable silt
and gravel content, with the outwash including the least amount fines and the glacial till including the
most. We anticipate that it will be feasible to re-use the outwash with a lower fines content under a
relatively wide variety of weather conditions, but use of soils with more than about 5 percent fines will
depend on the weather conditions at the time of placement and compaction. The native outwash is well-
suited for use as structural fill. Please note that native glacial till and existing fill material may contain a
relatively high silt content. Unless grading takes place during relatively dry weathers, using these materials
as structural fill could be difficult due to the high fines content and moisture sensitivity. Re-using over-
optimum soils during periods of wetter, cooler weather would likely require stabilization with Portland
cement.
We recommend that site soils used as structural fill have less than 4 percent organics by weight and have
no woody debris greater than ½ inch in diameter. We recommend that all pieces of organic material
greater than ½ inch in diameter be picked out of the fill before it is compacted. Organic-rich soil derived
from earthwork activities should be used in landscaping areas or be wasted from the site.
Imported Structural Fill: Imported structural fill may be required due to weather, wet soil conditions, or
other reasons. The appropriate type of imported structural fill will depend on the prevailing weather
conditions. During extended periods of dry weather when soil moisture can be controlled, we recommend
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that imported fill meet the requirements of Common Borrow, Options 1 or 2, as specified in Section 9-
03.14(3) of the Washington State Department of Transportation, Standard Specifications. During wet
weather, higher-quality (lower fines content) structural fill might be required, as Common Borrow may
contain sufficient fines to be moisture sensitive. During wet weather we recommend that imported
structural fill meet the general requirements of Gravel Borrow as specified in Section 9-03.14(1) of the
WSDOT Standard Specifications although we recommend that the fines content be limited to 5 percent
based on the soil fraction passing the ¾-inch sieve.
Compaction Recommendations: Structural fill should be placed in horizontal lifts and compacted to a firm
and non-yielding condition using equipment and procedures that will produce the recommended
moisture content and densities throughout the fill. Fill lifts should generally not exceed 10 inches in loose
thickness, although the nature of the compaction equipment in use and its effectiveness will influence
functional fill lift thicknesses. Recommended compaction criteria for structural fill materials, are as
follows:
Soil Compaction Recommendations
Location Minimum Percent Compaction*
Below foundations and slabs 95
Under pavements and sidewalks 95
Fill sections of the site 95
Trenches, foundation, slab, and retaining wall backfill 95
All other non-structural areas 90
* ASTM D 1557 Modified Proctor Maximum Dry Density
Earthwork may be difficult or impossible during periods of elevated soil moisture and wet weather. If
soils are stockpiled for future use and wet weather is anticipated, the stockpile should be protected with
plastic sheeting that is securely anchored.
Subgrade soils that become disturbed due to elevated moisture conditions should be overexcavated to
expose firm, non-yielding, non-organic soils and backfilled with compacted structural fill. We recommend
that the earthwork portion of this project be completed during extended periods of dry weather if
possible. If earthwork is completed during the wet season (typically November through May) it will be
necessary to take extra precautionary measures to protect subgrade soils. Wet season earthwork may
require additional mitigative measures beyond that which would be expected during the drier summer
and fall months. This could include diversion of surface runoff around exposed soils and draining of
ponded water. Once subgrades are established, it will be necessary to protect the exposed subgrade soils
from construction traffic during wet weather. Placing quarry spalls or crushed recycled concrete over
these areas would further protect the soils from construction traffic. Protection of subgrades should be
expected in the portions of the site where native glacial till and existing fill with higher fines content are
present at shallow depths.
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If earthwork takes place during freezing conditions, we recommend allowing the exposed subgrade to
thaw and then recompacting the subgrade prior to placing subsequent lifts of engineered fill. Frozen soil
should not be used as structural fill.
Drainage: Positive drainage should be provided during construction and maintained throughout the life
of the project. Uncontrolled movement of water into trenches or foundation and slab excavations during
construction should be prevented. Final site grades should be sloped to carry surface water away from
the building and other drainage-sensitive areas. Additionally, site grades should be designed such that
concentrated runoff on softscape surfaces is avoided.
Utility Installation Recommendations
Below-grade utilities are expected to include conduits and storm drain piping and structures. We
recommend that utility trenching conform to all applicable federal, state, and local regulations, such as
OSHA and WISHA, for open excavations. The existing native soils in the park footprint are generally
expected to be adequate for support of utilities.
All trenches should be wide enough to allow for compaction around the haunches of the pipe. If water is
encountered in the excavations, it should be removed prior to fill placement. Materials, placement and
compaction of utility trench backfill exclusive of CDF should be in accordance with the recommendations
presented in the Structural Fill section of this report. In our opinion, the initial lift thickness should not
exceed one foot unless recommended by the manufacturer to protect utilities from damage by
compacting equipment. Light, hand operated compaction equipment may be utilized directly above
utilities if damage resulting from heavier compaction equipment is of concern.
Dewatering: Depending upon the time of year that the work takes place and the depth of the utilities,
excavations may encounter perched groundwater. The contractor should be prepared to pump water
from excavations as necessary to maintain a relatively dry trench condition. We anticipate that the
likelihood of encountering water in excavations will be highest in in proximity to the locations of B-2 and
B-6, where groundwater was encountered at depths of approximately 6.5 feet and 9 feet, respectively,
during our subsurface exploration conducted during the dry season.
Temporary and Permanent Slopes: We recommend that utility trenching, installation, and backfilling
conform to all applicable Federal, State, and local regulations such as WISHA and OSHA regulations for
open excavations. In order to maintain the function of any existing utilities that may be located near
excavations, we recommend that temporary excavations not encroach upon the bearing splay of existing
utilities, foundations, or slabs. The bearing splay of structures and utilities should be considered to begin
at the edge of the utility, foundation, or slab and extend downward at a 1H:1V (Horizontal:Vertical) slope.
If, due to space constraints, an open excavation cannot be completed without encroaching on a utility,
we recommend shoring the new utility excavation with a slip box or other suitable means that provide for
protection of workers and that maintain excavation sidewall integrity to the depth of the excavation.
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Temporary slope stability is a function of many factors, including the following:
• The presence and abundance of groundwater;
• The type and density of the various soil strata;
• The depth of cut;
• Surcharge loadings adjacent to the excavation;
• The length of time the excavation remains open.
It is exceedingly difficult to pre-establish a safe and “maintenance-free” temporary cut slope angle.
Therefore, it should be the responsibility of the contractor to maintain safe slope configurations since the
contractor is continuously at the job site, able to observe the nature and condition of the cut slopes, and
able to monitor the subsurface materials and groundwater conditions encountered. It may be necessary
to drape temporary slopes with plastic or to otherwise protect the slopes from the elements and minimize
sloughing and erosion. We do not recommend vertical slopes or cuts deeper than 4 feet if worker access
is necessary. The cuts should be adequately sloped or supported to prevent injury to personnel from local
sloughing and spalling. The excavation should conform to applicable Federal, State, and local regulations.
Based upon our review of WAC Chapter 296-155-66401 (Appendix A – Soil Classification), we have
interpreted the existing fill and outwash soils disclosed by the explorations and likely to be present in most
excavations as consistent with the Type C definition. We interpret the native glacial till only encountered
in the northwestern site area as consistent with the Type A definition. The contractor should be
responsible for determining soil types in all excavations at the time of construction and should be
prepared to adequately shore or slope all excavations. Please note that some of the granular soils have a
low fines content and that unsupported excavation sidewalls in these soils may slough or cave.
We recommend that all permanent cut or fill slopes constructed in native or properly compacted fill soils
be designed at a 2H:1V (Horizontal:Vertical) inclination or flatter. All permanent cut and fill slopes should
be adequately protected from erosion both temporarily and permanently.
Shallow Foundation Design Recommendations and Considerations
We anticipate that new structures (shelter, plaza, retaining walls, and pedestrian bridge) may be
supported by conventional shallow spread footings. Native granular soils, existing fill soils with no more
than about 3 percent organics and lacking deleterious debris that are at least medium dense, and properly
compacted structural fill are adequate for support of shallow foundations.
Based on conditions observed at the locations of borings completed at or near the proposed shelter and
plaza locations, we anticipate that foundation subgrade soils for the shelter will largely consist of dense
native sand with a variable silt and gravel content. We anticipate that foundation subgrade soils for the
proposed plaza may encounter loose silty sand with a variable gravel content fill soils. B-4 was completed
at the proposed plaza location and disclosed approximately 4.5 feet of loose fill soils above dense native
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soil. Boring B-1 was completed near the proposed location of culverts or pedestrian bridge and disclosed
approximately 4.5 feet of loose fill soils above dense native soil.
In the event that loose fill soils or soils containing organics material or deleterious debris are encountered
at foundation subgrade elevation, the excavations should be extended deeper to adequate bearing soils.
The footings could bear directly on suitable soils at the lower level, on lean concrete or CDF backfill placed
in the excavations, or the footings may bear on properly compacted backfill extending down to the denser
soils.
Overexcavation of inadequate soils below footings should extend laterally beyond all edges of the footings
a distance of 2 feet per 3 feet of overexcavation depth below footing base elevation. The overexcavation
should then be backfilled up to the footing base elevation with the excavated material or other granular
material placed in lifts of 10 inches or less in loose thickness and compacted to at least 95 percent of the
material's modified Proctor maximum dry density (ASTM D 1557). If excavations are backfilled with lean
mix concrete or CDF, we recommend the material have a minimum compressive strength of 125 psi.
When using CDF, the overexcavation need only be 1 foot wider than the foundation on all sides.
Provided the recommendations in this report are adhered to, we recommend the following criteria for
shallow foundations:
• Net allowable bearing pressure: 2,500 psf for at least medium dense soils, or 4,000 psf for at least
dense native glacial till soils. These values incorporates a factor of safety of 3. A one-third
increase may be applied for short-term wind or seismic loading.
• Minimum dimensions: 12 inches
• Minimum embedment for frost protection: 18 inches
• Estimated total settlement: ½ inch
• Estimated differential settlement: One half of total settlement
• Ultimate passive resistance: 425 pcf. This value assumes that foundations are backfilled with
granular backfill compacted to 95 percent density and does not include a factor of safety. Neglect
the upper 18 inches of embedment when calculating passive resistance.
• Ultimate coefficient of base friction: 0.45
The base of all foundation excavations should be free of water, loose soil, or debris prior to placing
concrete and should be compacted as recommended in this report. Concrete should be placed soon after
excavating and compaction to reduce bearing soil disturbance. Should the soils at bearing level become
excessively dry, disturbed, saturated, or frozen, the affected soil should be removed prior to placing
concrete. A 6-inch thick lift of compacted crushed rock or a lean concrete mud mat should be placed over
the bearing soils if the excavations must remain open for an extended period of time. It is recommended
that a ZGA representative evaluate foundation subgrades prior to placing the crushed rock and prior to
form and reinforcing steel placement.
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Slab Base: We anticipate that proposed structures (shelter, plaza, and Portland loo) will incorporate slabs.
To provide a uniform slab bearing surface, capillary break, and even working surface, we recommend the
on-grade slabs be underlain by a 6-inch thick layer of compacted crushed rock meeting the requirements
of Crushed Surfacing Top Course as specified in Section 9-03.9(3) of the WSDOT Standard Specifications
with the modification that a maximum of 7 percent of the material pass the U.S. No 200 sieve.
Vapor Barrier: Where potential slab moisture is a concern or where moisture sensitive floor coverings are
planned, we recommend using a 15-mil, puncture-resistant proprietary product such as Stego Wrap, or
an approved equivalent that is classified as a Class A vapor retarder in accordance with ASTM E 1745.
Overlap lengths and the appropriate tape used to seal the laps should be in accordance the vapor retarder
manufacturer’s recommendations. When conditions warrant the use of a vapor retarder, the slab
designer and slab contractor should refer to ACI 302 and ACI 360 for procedures and cautions regarding
the use and placement of a vapor retarder/barrier.
Retaining Walls
Several retaining walls approximately 2.25 feet tall or less in exposed vertical height will be installed along
the proposed concrete pathway which will be constructed in the western half of the park. We anticipate
that the retaining walls will require cuts of approximately 1 foot to establish the wall subgrade elevation,
followed by fills of 3 feet or less for backfill. Additional recommendations for these structures are provided
below.
Lateral Earth Pressures: The lateral soil pressures acting on backfilled retaining walls will depend on the
nature and density of the soil behind the wall, and the ability of the wall to yield in response to the earth
loads. Yielding walls (i.e. walls that are free to translate or rotate) that are able to displace laterally at
least 0.02H, where H is the height of the wall, may be designed for active earth pressures. Non-yielding
walls (i.e. walls that are not free to translate or rotate) should be designed for at-rest earth pressures.
Non-yielding walls include walls that are braced to another wall or structure, and wall corners.
Assuming that walls are backfilled and drained as described in the following paragraphs, we recommend
that yielding walls supporting horizontal backfill be designed using an equivalent fluid density of 35 pcf
(active earth pressure). Non-yielding walls should be designed using an equivalent fluid density of 50 pcf
(at-rest earth pressure).
The above-recommended lateral earth pressures do not include the effects of sloping backfill surfaces. If
such conditions exist, we should be consulted to provide revised earth pressure recommendations.
Drainage: Backfilled retaining walls must be provided with adequate drainage measures installed to
collect and direct subsurface water away from the walls and prevent the build-up of hydrostatic pressures.
All backfilled walls should include a drainage aggregate zone extending one foot from the back of wall to
within 6 inches of the top of the wall. The granular backfill should be covered with a geotextile fabric,
such as Mirafi 140N, or equivalent. Topsoil may be placed above the fabric. The drainage aggregate
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should consist of material meeting the requirements of WSDOT 9-03.12(2) Gravel Backfill for Walls.
Footing drains should consist of a minimum 4-inch diameter, Schedule 40, rigid, perforated PVC pipe
placed at the base of the heel of the footing with the perforations facing down. The pipe should be
surrounded by a minimum of 6 inches of clean free-draining granular material conforming to WSDOT
Standard Specification 9-03.12(4), Gravel Backfill for Drains. A non-woven filter fabric such as Mirafi 140N,
or equivalent, should envelope the free-draining granular material. At appropriate intervals such that
water backup does not occur, the drainpipe should be connected to a tightline system leading to a suitable
discharge. Cleanouts should be provided for future maintenance. Alternatively, the walls may be
equipped with weepholes.
Light Pole Foundations
Proposed site improvements include new or replaced light poles, which may include cast-in-place or pre-
cast foundations. Vertical and lateral support for pole or post foundations will primarily be obtained
primarily from medium dense to dense sandy soils typically encountered within the anticipated
embedment depth of the foundations. Drilled shafts may require casing due to the caving of the native
soils. If water is present in the bottom of the excavation, we recommend the concrete be tremied to the
bottom to displace the water and not dilute the concrete.
Light pole foundations supported in the native medium dense soils may be designed for a maximum
allowable end bearing pressure of 2,500 psf. This value may be increased by 1/3 to resist short-term
transient loads such as wind and seismic loads.
An allowable lateral bearing pressure of 2,500 psf may be used for design completed in accordance with
procedures described in Chapter 17 of the WSDOT Geotechnical Design Manual.
If the pole foundations are constructed with permanent casing, we recommend that the annular space
between the casing and the native soil be backfilled with CDF unless there is sufficient space to place and
compact structural fill around the form.
Seismic Design Parameters
Category Designation or Value
2012/2015 International Building Code (IBC) 1 Site Class D
Ss Spectral Acceleration for a Short Period 1.419g (Site Class B)
S1 Spectral Acceleration for a 1-Second Period 0.53g (Site Class B)
SMs Spectral Acceleration for a Short Period 1.419g (Site Class D)
SM1 Spectral Acceleration for a 1-Second Period 0.795g (Site Class D)
1. In general accordance with ASCE 7, Table 20.3-1.
2. The 2012/2015 International Building Code, and by reference ASCE 7, considers a site soil profile
determination extending a depth of 100 feet for seismic site classification. The current authorized
scope did not include the required 100-foot soil profile determination. The explorations advanced
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as part of our evaluation extended to a maximum depth of approximately 11-1/2 feet and this seismic
site class definition considers that medium dense to dense and stiff soils as noted on the published
geologic mapping exist below the maximum depth of the subsurface exploration. Additional
exploration to greater depths could be considered to confirm the conditions below the current depth
of exploration, if necessary.
Stormwater Infiltration Considerations
Field Testing: We performed three Small-Scale Pilot Infiltration Tests in general accordance with the 2016
King County Surface Water Design Manual (2016 Manual). The infiltration tests were completed by
methods described in Appendix A. Soils disclosed at the elevations of the field infiltration tests consisted
of native glacial till within TP-1/IT-1, and native outwash sand and gravel within TP-2/IT-2 and TP-3/IT-3.
Testing data are summarized in the table below.
Field Infiltration Testing Summary
Infiltration Test
Number
Approx. Ground
Surface Elevation
(feet)
Approx. Test
Depth/Elevation (feet)
Observed Unfactored
Infiltration Rate
(inches/hour)
TP-1/IT-1 376 3 / 373 0.0625
TP-2/IT-2 384 4 / 380 21.4
TP-3/IT-3 382 4.5/388.5 1.24
Test IT-1 was completed at the far north end of the site near the park sign. We encountered medium
dense to dense silty fine to medium sand with gravel (glacial till) at this location. IT-1 was completed at a
depth of approximately 3 feet and we observed a water level drop of only approximately 1/8th inch over
two hours and from the practical perspective this area should not be considered suitable for conventional
infiltration.
Test IT-2 was completed in medium dense granular outwash sands with a relatively low fines content at a
depth of approximately 4 feet and was located downslope of the main parking lot accessed from Beacon
Way South. We observed an unfactored infiltration rate of 21.4 inches/hour. We observed groundwater
at approximately 9 feet while advancing boring B-6 (located adjacent to the infiltration test), so it appears
that there should be at least 3 feet of separation between an infiltration BMP 4 to 5 feet deep and the
seasonal high groundwater condition. We tested two soil samples from below the infiltration test depth
for Cation Exchange Capacity (CEC) and organic content. Both samples had CEC values exceeding 5
meq/100g and organic matter contents exceeding 1 percent, so the material may be useful in terms of
providing some treatment for groundwater protection outside of a groundwater protection area per the
2016 Manual.
Test IT-3 was completed in the low area adjacent to Jones Avenue South and east of the intersection with
South 9th Street. Boring B-2 disclosed medium dense granular outwash sands with a relatively low fines
content, but groundwater was encountered at approximately 6.5 feet while drilling B-2 (located adjacent
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to the infiltration test). Consequently, we completed the infiltration test at a depth of 3 feet. We
observed an unfactored infiltration rate of 1.24 inches/hour. Two soil samples from below the infiltration
test depth were evaluated for CEC and organic content and offered mixed results. Both samples included
CEC values less than 5 meq/100g. However, the organic matter contents exceeded 1 percent.
Design Infiltration Rate: The 2016 Manual provides the following methodology for determining a design
infiltration rate based on field testing results and site conditions. The equation for determining the design
infiltration is shown below:
IDesign = IMeasured X FTesting X FGeometry X FPlugging, where:
IDesign is the design infiltration rate.
IMeasured is the observed field infiltration test rate in inches/hour.
FTesting is a factor to account for uncertainties in the field testing methodology. The 2016 Manual calls for
using a value of 0.5 for the small-scale Pilot Infiltration Test Method.
FGeometry is a factor that accounts for the influence of infiltration feature geometry and the depth to the
water table or impervious strata. FGeometry is defined as 4D/W +0.05 where D = the depth from the bottom
of the infiltration feature to the maximum wet season groundwater table or nearest impervious strata,
whichever is less, and W is the width of the infiltration feature. FGeometry must be between 0.25 and 1.0.
FGeometry is a factor that is most applicable to pond-type infiltration features that have a relatively large
width, W, relative to D, and is not particularly useful when assessing long and narrow features, such as
ditches or swales. We considered an FGeometry value of 1.0 in our analysis.
FPlugging accounts for reductions in infiltration rates over the long term due to plugging of the receptor soils.
The Manual requires using the following values for FPlugging as a function of soil type: 0.7 for loams and
sandy loams, 0.8 for fine sands and loamy sands, 0.9 for medium sands, and 1.0 for coarse sands or
cobbles. We considered a value of 0.8 in our analysis based on our laboratory testing of soil samples.
Based on the results of our field testing and considering the recommended factors provided in the 2016
Manual, we recommend utilizing a design infiltration rate of 8 inches per hour for infiltration facilities
proposed in the location of IT-2 between depths of approximately 4 and 5 feet, and a design infiltration
rate of 0.5 inches per hour for infiltration facilities proposed in the location of IT-3 at an approximate
depth of 3 feet. We do not recommend utilizing conventional infiltration techniques in the location of
IT-1 due to the observed very low infiltration testing results and high fines content of the glacially
consolidated soil.
USDA Soil Classification: We completed grain size distribution tests per the USDA testing procedure that
considers the soil fraction passing the US No. 10 sieve (soil particles less than 2 millimeters) on select
samples from borings conducted at the approximate locations of the proposed infiltration facilities. The
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selected samples represent soil grain size distribution at and below proposed infiltration facility locations.
The test results are summarized in the table below and grain size distribution curves are presented in
Appendix B. Based on USDA sieve methodology, the tested soil samples generally meet the classification
of Loamy Sand at the IT-1 location and Sand at the IT-2 and IT-3 locations.
Groundwater Considerations: Groundwater was observed while drilling two borings in proximity to the
location of proposed infiltration facilities. Boring B-2 was performed near IT-3 and extended to 11.5 feet
below grade. We observed groundwater at a depth of about 6.5 feet below existing grade while advancing
B-2. Boring B-6 was performed near IT-2 and extended to 11.5 feet below grade. We observed
groundwater at a depth of about 9 feet below existing grade while advancing B-6. It should be noted that
the site was being actively irrigated at the time we completed our explorations. We did not observe soil
coloration mottling in the recovered samples that may suggest a seasonally higher groundwater condition.
A better-defined extent of seasonal groundwater fluctuation would require monitoring groundwater
conditions over at least one year (this was not included in our approved scope of services).
Groundwater was encountered within the relatively permeable outwash soils. Groundwater was not
encountered within the lowest elevation boring (B-7) where relatively impermeable glacial till soils were
encountered. As such, the groundwater encountered during exploration is interpreted to represent a
perched groundwater condition which may be occurring within the permeable outwash soils due to the
presence of hydraulically restrictive soils at greater depth.
Temporary Sedimentation Facility Considerations: The infiltration rate of the receptor soils will be
reduced in the event that fine sediment or organic materials are allowed to accumulate on and within the
exposed receptor soils. The use of an infiltration facility as a temporary sedimentation control feature
during construction has the potential to substantially alter the infiltration rate of the soils. Use of an
infiltration facility as a temporary construction phase sedimentation feature is not recommended. If site
conditions are such that this cannot be avoided, it will likely be necessary to excavate the soils below the
sedimentation pond bottom that have been contaminated with sediment, organic materials, or other
deleterious materials that may reduce the permeability of the granular receptor soils prior to operation
of the facility for infiltration purposes. Field testing may be necessary as well in order to verify that the
USDA Grain Size Distribution Testing Results
Exploration and Sample Percent Passing per US Standard Sieve
20 40 60 100 200 325
B-2, S-2 85 63 45 32 20 11
B-2, S-3 81 44 21 12 8 4
B-2, S-4 97 71 21 7 4 2
B-6, S-2 85 53 37 26 16 9
B-6, S-3 77 46 31 22 13 7
B-6, S-4 88 25 10 5 3 1
B-7, S-3 77 60 45 32 21 13
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restoration activity has been successful and that the infiltration rate of the receptor soils is consistent with
that considered in the analysis.
Erosion Control
Construction phase erosion control activities are recommended to include measures intended to reduce
erosion and subsequent sediment transport. We recommend that the project incorporate the following
erosion and sedimentation control measures during construction:
• Capturing water from low permeability surfaces and directing it away from bare soil exposures,
keeping runoff velocities as low as possible.
• Erosion control BMP inspection and maintenance: The contractor should be aware that
inspection and maintenance of erosion control BMPs is critical toward their satisfactory
performance. Repair and/or replacement of dysfunctional erosion control elements should be
anticipated.
• Undertake site preparation, excavation, and filling during periods of little or no rainfall.
• Cover excavation surfaces with anchored plastic sheeting if surfaces will be left exposed during
wet weather.
• Minimize extent of exposed soil at one time.
• Retain sediment within working areas.
• Cover soil stockpiles with anchored plastic sheeting.
• Provide an all-weather quarry spall construction site entrance.
• Provide for street cleaning on an as-needed basis.
• Protect exposed soil surfaces that will be subject to vehicle traffic with crushed rock or crushed
recycled concrete to reduce the likelihood of subgrade disturbance and sediment generation
during wet weather or wet site conditions.
• Install perimeter siltation control fencing on the lower perimeter of work areas.
Pavement
Asphalt Pavements: The following pavement sections represent our minimum recommendations for an
average level of performance during a 20-year design life; therefore, an average level of maintenance will
likely be required. A 20-year pavement life typically assumes that an overlay will be placed after about 12
years. Thicker asphalt, base, and subbase courses would offer better long-term performance, but would
cost more initially. Conversely, thinner courses would be more susceptible to “alligator” cracking and
other failure modes. As such, pavement design can be considered a compromise between a high initial
cost and low maintenance costs versus a low initial cost and higher maintenance costs.
The native subgrade soils are anticipated to consist primarily of sand with variable silt and gravel content.
Based on our experience with similar soils, we have estimated a California Bearing Ration (CBR) value of
15 percent for this project.
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We recommend that the upper 12 inches of pavement subgrades be prepared in accordance with the
recommendations presented in the Subgrade Preparation section of this report.
We recommend that the crushed aggregate base course conform to Section 9-03.9(3) of the WSDOT
Standard Specifications. All base material should be compacted to at least 95 percent of the maximum
dry density determined in accordance with ASTM: D 1557.
Asphalt Recommendations: The following asphalt pavement sections have been developed to be placed
and compacted in one lift. For light duty pavements (parking stall areas), we recommend 2½ inches of
asphalt concrete over 4 inches of crushed rock base course. For heavy duty pavements (main access
roads, truck delivery routes, etc.), we recommend 3½ inches of asphalt concrete over 6 inches of crushed
rock base course. We recommend that the asphalt concrete conform to Section 9-02.1(4) for PG 58-22 or
PG 64-22, Performance Graded Asphalt Binder as presented in the WSDOT Standard Specifications. We
also recommend that the gradation of the asphalt aggregate conform to the aggregate gradation control
points for ½-inch mixes as presented in Section 9-03.8(6), HMA Proportions of Materials. We recommend
that asphalt be compacted to a minimum of 92 percent and a maximum of 96 percent of the Rice
(theoretical maximum) density.
Concrete Pavements: Concrete pavement design recommendations are based on an assumed modulus of
rupture of 600 psi and a minimum compressive strength of 4,000 psi for the concrete. For light duty
pavements, we recommend 5 inches of concrete over 4 inches of crushed aggregate base. For heavy duty
pavements, we recommend 6 inches of concrete over 4 inches of crushed aggregate base. We
recommend that concrete pavements be lightly reinforced with 6x6-W2.0xW2.0 welded wire fabric or
equivalent to control cracking and have relatively closely spaced control joints on the order of 10 to 15
feet. We further recommend that loading dock and trash enclosure pavements be reinforced with #4 bars
at 15 inches on center each direction.
CLOSURE
The analysis and recommendations presented in this report are based, in part, on the explorations
completed for this study. The number, location, and depth of the explorations were completed within
the constraints of budget and site access so as to yield the information to formulate our
recommendations. Project plans were in the preliminary stage at the time this report was prepared. We
therefore recommend we be provided an opportunity to review the final plans and specifications when
they become available in order to assess that the recommendations and design considerations presented
in this report have been properly interpreted and implemented into the project design.
The performance of earthwork, structural fill, foundations, and slabs depends greatly on proper site
preparation and construction procedures. We recommend that Zipper Geo Associates, LLC be retained
to provide geotechnical engineering services during the earthwork-related construction phases of the
project. If variations in subsurface conditions are observed at that time, a qualified geotechnical engineer
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could provide additional geotechnical recommendations to the contractor and design team in a timely
manner as the project construction progresses.
This report has been prepared for the exclusive use of the City of Renton Parks Department, Hough, Beck,
and Baird, Inc. and their agents, for specific application to the project discussed and has been prepared in
accordance with generally accepted geotechnical engineering practices. No warranties, express or
implied, are intended or made. Site safety, excavation support, and dewatering requirements are the
responsibility of others. In the event that changes in the nature, design, or location of the project as
outlined in this report are planned, the conclusions and recommendations contained in this report shall
not be considered valid unless ZGA reviews the changes and either verifies or modifies the conclusions of
this report in writing.
B-1
B-3
B-2
B-4
B-5
B-7
B-6
TP-3/IT-3
TP-2/IT-2
TP-1/IT-1
HA-1
HA-2
HA-3
APPROXIMATE SCALE IN FEET
080 8040
REFERENCE: URBAN DESIGN PLAN AND NOTES PROVIDED BY HBB, DATED AUGUST 17, 2020
FIGURE
Job No.
Zipper Geo Associates, LLC
19019 36th Ave. W.,Suite E
Lynnwood, WA, 98036 SHT. of11
SITE AND EXPLORATION PLAN
2294.01OCTOBER 2020
1
Phillip Arnold Park
720 Jones Avenue South
Renton, Washington
LEGEND
BORING NUMBER AND
APPROXIMATE LOCATION
HAND AUGER NUMBER AND
APPROXIMATE LOCATION
TEST PIT AND INFILTRATION
TEST NUMBER AND
APPROXIMATE LOCATION
APPENDIX A
FIELD EXPLORATION AND TESTING PROCEDURES AND LOGS
FIELD EXPLORATION AND TESTING PROCEDURES AND LOGS
Our field exploration program for this project included completing a visual reconnaissance of the site,
advancing seven borings (B-1 through B-7), excavating three test pits and performing three infiltration
tests (TP-1/IT-1 through TP-3/IT-3), and completing three hand auger borings (HA-1 through HA-3). The
approximate exploration and infiltration test locations are presented on Figure 1, the Site and Exploration
Plan. Exploration locations were determined in the field using steel and fiberglass tapes by measuring
distances from existing site features shown on a preliminary site plan, dated August 17, 2020, provided
by HBB. The ground surface elevation at each exploration location was interpolated from the topography
shown on a survey, dated 4 February 2020, prepared by Bush, Roed, & Hitchings, Inc. As such, the
exploration and field test locations should be considered accurate to the degree implied by the
measurement method. The following sections describe our procedures associated with the explorations.
Descriptive logs of the explorations are enclosed in this appendix.
Boring Procedures
The borings were advanced using a track-mounted drill rig operated by an independent drilling company
working under subcontract to ZGA (Geologic Drill Partners). The borings were advanced using hollow
stem auger drilling methods. A geologist from our firm continuously observed the borings, logged the
subsurface conditions encountered, and obtained representative soil samples. All samples were stored
in moisture-tight containers and transported to our laboratory for further evaluation and testing. Samples
were generally obtained by means of the Standard Penetration Test at 2.5-foot to 5-foot intervals
throughout the drilling operation.
The Standard Penetration Test (ASTM D 1586) procedure consists of driving a standard 2-inch outside
diameter steel split spoon sampler 18 inches into the soil with a 140-pound hammer free falling 30 inches.
The number of blows required to drive the sampler through each 6-inch interval is recorded, and the total
number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or
“blow count” (N value). If a total of 50 blows are struck within any 6-inch interval, the driving is stopped
and the blow count is recorded as 50 blows for the actual penetration distance. The resulting Standard
Penetration Resistance values indicate the relative density of granular soils and the relative consistency
of cohesive soils.
The enclosed boring logs describe the vertical sequence of soils and materials encountered in each boring,
based primarily upon our field classifications. Where a soil contact was observed to be gradational, our
logs indicate the average contact depth. Where a soil type changed between sample intervals, we inferred
the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and
approximate depth of each soil sample obtained from the boring. If groundwater was encountered in a
borehole, the approximate groundwater depth and date of observation are depicted on the log.
Test Pit Procedures
An independent contractor working under subcontract to ZGA (NW Excavating and Trucking, LLC)
excavated the test pits through the use of a small tracked excavator. Three geologists from ZGA
continuously observed the test pit excavations, logged the subsurface conditions, and obtained
representative soil samples. The samples were stored in moisture tight containers and transported to our
laboratory for further visual classification and testing.
The enclosed test pit logs indicate the vertical sequence of soils and materials encountered in each test
pit, based primarily on our field classifications and supported by our subsequent laboratory testing.
Where a soil contact was observed to be gradational or undulating, our logs indicate the average contact
depth. We estimated the relative density and consistency of in situ soils by means of the excavation
characteristics and by the sidewall stability. Our logs also indicate the approximate depths of any sidewall
caving or groundwater seepage observed in the test pits, as well as all sample numbers and sampling
locations.
Hand Auger Procedures
A geologist from our firm advanced a 3.5-inch diameter auger by hand, continuously observing the soil
cuttings as they were retrieved. The enclosed hand auger logs indicate the vertical sequence of soils and
materials encountered in the explorations, based primarily on our field classifications. Where a soil
contact was observed to be gradational or undulating, our log indicates the average contact depth. The
hand auger borings were performed near the proposed basketball court renovations and bleachers for
the primary purpose of determining stripping depth.
Field Infiltration Testing Procedures
Three field infiltration tests were completed at the locations of test pits IT-1 through IT-3 on 27 August
and 28 August 2020 by ZGA geologists working with a local subcontractor with a small tracked excavator
(NW Excavating and Trucking, LLC). Water was sourced from the park’s irrigation system. The
approximate infiltration test locations are illustrated on Figure 1. The field infiltration testing procedures
were completed in general accordance with the Small-scale Pilot Infiltration Test (PIT) method as
described in Reference 6A Infiltration Test Methods in the King County 2016 Surface Water Design Manual
(KC Manual). The field infiltration testing procedures are summarized below. Test results are discussed
in the report text.
The excavator was used to excavate to a depth at or below the invert elevation of proposed infiltration
systems. The test excavations typically had minimum dimensions of approximately 4 feet by 3 feet,
extending 3 to 4 feet deep.
Pea gravel was placed within the test pits to prevent siltation a length of slotted PVC pipe was placed on
the excavation bottom, and water was introduced into the slotted PVC pipe by hose. An in-line flow meter
and five-gallon buckets allowed measuring the rate at which water was introduced into the excavations
as well as the total volume used for each test.
Soils were pre-soaked for a minimum of 6 hours on 27 August 2020 and water utilized during the pre-soak
was left in the infiltration test pits overnight. Constant head testing was completed for one hour at each
infiltration test location on 28 August 2020. Once constant head testing was completed at each infiltration
test pit, falling head tests with at least 6-inch water depth were completed.
Following completion of the tests, the trackhoe was used to excavate below the test surface in order to
observe soil conditions immediately below the test elevation and to determine whether perching layers
were present or whether some other condition that could affect the infiltration rate was present. The
excavations were then backfilled with bucket-tamped excavation spoils.
Borings performed near the infiltration test locations and extended at least 5 feet below proposed
infiltration facility bottoms. The borings were performed to verify groundwater and soil conditions below
infiltration facility grades, and to minimize the amount of soil disturbance during test pit excavation.
ZIPPER GEO ASSOCIATES, LLC
19019 36th Avenue West, Suite E, Lynnwood, Washington 98036
Hand Auger Boring HA-1
Location: See Site and Exploration Plan, Figure 1
Approx. Ground Surface Elevation: 389 Feet
Project: Phillip Arnold Park
Project No: 2294.01
Date Excavated: 8/28/20
Depth
(ft)
Material Description
Sample
NC
%M
Testing
1
Approximately 3 inches of grass and sod over loose, moist,
brown, silty SAND, some gravel, thin root intrusions
Hand auger terminated at approximately 6 inches below
existing site grades following verification of sod depth.
Groundwater was not observed at time of drilling.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Note: NC is the Dynamic Cone Penetrometer blow count per 1.75 inch interval measured in accordance with ASTM Special Technical Publication #399.
ZIPPER GEO ASSOCIATES, LLC
19019 36th Avenue West, Suite E, Lynnwood, Washington 98036
Hand Auger Boring HA-2
Location: See Site and Exploration Plan, Figure 1
Approx. Ground Surface Elevation: 390 Feet
Project: Phillip Arnold Park
Project No: 2294.01
Date Excavated: 8/28/20
Depth
(ft)
Material Description
Sample
NC
%M
Testing
1
Approximately 3 inches of grass and sod over loose, moist,
brown, silty SAND, some gravel, thin root intrusions
Hand auger terminated at approximately 6 inches below
existing site grades following verification of sod depth.
Groundwater was not observed at time of drilling.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Note: NC is the Dynamic Cone Penetrometer blow count per 1.75 inch interval measured in accordance with ASTM Special Technical Publication #399.
ZIPPER GEO ASSOCIATES, LLC
19019 36th Avenue West, Suite E, Lynnwood, Washington 98036
Hand Auger Boring HA-3
Location: See Site and Exploration Plan, Figure 1
Approx. Ground Surface Elevation: 386 Feet
Project: Phillip Arnold Park
Project No: 2294.01
Date Excavated: 8/28/20
Depth
(ft)
Material Description
Sample
NC
%M
Testing
1
Approximately 5 inches of grass and sod over loose, moist,
brown, silty SAND, some gravel, thin root intrusions
Hand auger terminated at approximately 6 inches below
existing site grades following verification of sod depth.
Groundwater was not observed at time of drilling.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Note: NC is the Dynamic Cone Penetrometer blow count per 1.75 inch interval measured in accordance with ASTM Special Technical Publication #399.
ZIPPER GEO ASSOCIATES, LLC
19019 36th Avenue West, Suite E, Lynnwood, Washington 98036
Test Pit TP-1/IT-1
Location: See Site and Exploration Plan, Figure 1
Approx. Ground Surface Elevation: 376 Feet
Project: Phillip Arnold Park
Project No: 2294.01
Date Excavated: August 27, 2020
Depth
(ft)
Material Description
Sample
NC
%M
Testing
1
Approximately 4 inches of grass and sod over loose, damp to
moist, brown silty SAND with gravel, concrete and wood
fragments, thin root intrusions (Fill)
Medium dense, moist, brownish gray, silty SAND with gravel,
soil mottling, weakly cemented (Loam per USDA)
Infiltration test performed at approximately 4.5 feet
Test pit completed to approximately 5 feet.
No groundwater observed at time of excavation.
2
3
S-1 @
3 feet
4
S-2 @4.5
feet
5
6
7
8
9
10
11
12
13
14
15
16
17
Note: NC is the Dynamic Cone Penetrometer blow count per 1.75-inch interval measured in accordance with ASTM Special Technical Publication #399.
ZIPPER GEO ASSOCIATES, LLC
19019 36th Avenue West, Suite E, Lynnwood, Washington 98036
Test Pit TP-2/IT-2
Location: See Site and Exploration Plan, Figure 1
Approx. Ground Surface Elevation: 384 Feet
Project: Phillip Arnold Park
Project No: 2294.01
Date Excavated: August 27, 2020
Depth
(ft)
Material Description
Sample
NC
%M
Testing
1
Approximately 4 inches of grass and sod over loose to
medium dense, moist, brown SAND some silt and gravel,
thin root intrusions in upper two feet (Loamy Sand per
USDA)
Infiltration test performed at approximately 4 feet
CEC 1-A: 5.4 meq/100g, OM 1-A: 2.0%
CEC 1-B: 5.2 meq/100g, OM 1-B: 1.8%
Test pit completed to approximately 4.5 feet.
No groundwater observed at time of excavation.
2
3
4
S-1 @ 4
feet
CEC/OM
5
6
7
8
9
10
11
12
13
14
15
16
17
Note: NC is the Dynamic Cone Penetrometer blow count per 1.75-inch interval measured in accordance with ASTM Special Technical Publication #399.
ZIPPER GEO ASSOCIATES, LLC
19019 36th Avenue West, Suite E, Lynnwood, Washington 98036
Test Pit TP-3/IT-3
Location: See Site and Exploration Plan, Figure 1
Approx. Ground Surface Elevation: 382 Feet
Project: Phillip Arnold Park
Project No: 2294.01
Date Excavated: August 27, 2020
Depth
(ft)
Material Description
Sample
NC
%M
Testing
1
Approximately 4 inches of grass and sod over loose to
medium dense, moist, dark brown SAND with silt and gravel,
thin root intrusions, trace organics, glass fragments (Fill)
Medium dense, moist, gray, SAND with silt and gravel
Infiltration test performed at approximately 3 feet (Loamy
Sand per USDA)
CEC 1-A: 3.7 meq/100g, OM: 1.3%
CEC 1-B: 4.2 meq/100g, OM: 1.5%
Test pit completed to approximately 3.5 feet.
No groundwater observed at time of excavation.
2
3
S-1 @ 3
feet CEC/OM
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Note: NC is the Dynamic Cone Penetrometer blow count per 1.75-inch interval measured in accordance with ASTM Special Technical Publication #399.
APPENDIX B
LABORATORY TESTING PROCEDURES AND RESULTS
LABORATORY PROCEDURES AND RESULTS
A series of laboratory tests were performed during the course of this study to evaluate the index and
geotechnical engineering properties of the subsurface soils. Descriptions of the types of tests performed
are given below.
Visual Classification
Samples recovered from the exploration locations were visually classified in the field during the
exploration program. Representative portions of the samples were carefully packaged in moisture tight
containers and transported to our laboratory where the field classifications were verified or modified as
required. Visual classification was generally done in accordance with ASTM D 2488. Visual soil
classification includes evaluation of color, relative moisture content, soil type based upon grain size, and
accessory soil types included in the sample. Soil classifications are presented on the exploration logs in
Appendix A.
Moisture Content Determinations
Moisture content determinations were performed on representative samples obtained from the
explorations in order to aid in identification and correlation of soil types. The determinations were made
in general accordance with the test procedures described in ASTM D 2216. The results are shown on the
exploration logs in Appendix A.
Grain Size Analysis
A grain size analysis indicates the range in diameter of soil particles included in a particular sample. Grain
size analyses were performed on representative samples in general accordance with ASTM D 6913. The
results of the grain size determinations for the samples were used in classification of the soils, and are
presented in this appendix.
Cation Exchange Capacity
Selected samples were tested for Cation Exchange Capacity (CEC) by a subcontract analytical testing
laboratory (AmTest Laboratories of Kirkland, Washington). The tests were completed in general accordance
with the EPA Laboratory Method 9081 testing procedure. The test results are presented in this appendix and
discussed in the report text.
Organic Content
Selected samples were tested for Organic Matter testing by a subcontract analytical testing laboratory
(AmTest Laboratories of Kirkland, Washington). The organic content of selected samples was determined
in general accordance with ASTM D 2974. The results of the tests are discussed in the report text.
0
10
20
30
40
50
60
70
80
90
100
0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS
GRAIN SIZE ANALYSIS
Comments: ASTM D 2487 Classification
36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200
Coarse Medium Fine Silt ClayFineCoarse
COBBLESBOULDERS GRAVEL SAND FINE GRAINED
SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER
Project No.:PROJECT NAME:
Philip Arnold ParkDATE OF TESTING:
Exploration Sample Depth (feet)Moisture (%)Fines (%)Description
B-2 2.5 4.8 SANDS-2 10.8
2294.01
9/1/2020
ASTM D 422, USDATest Results Summary
Zipper Geo Associates, LLC
Geotechnical and Environmental Consultants
0
10
20
30
40
50
60
70
80
90
100
0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS
GRAIN SIZE ANALYSIS
Comments: ASTM D 2487 Classification
36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200
Coarse Medium Fine Silt ClayFineCoarse
COBBLESBOULDERS GRAVEL SAND FINE GRAINED
SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER
Project No.:PROJECT NAME:
Philip Arnold ParkDATE OF TESTING:
Exploration Sample Depth (feet)Moisture (%)Fines (%)Description
B-2 5.0 14.8 SANDS-3 3.6
2294.01
9/1/2020
ASTM D 422, USDATest Results Summary
Zipper Geo Associates, LLC
Geotechnical and Environmental Consultants
0
10
20
30
40
50
60
70
80
90
100
0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS
GRAIN SIZE ANALYSIS
Comments: ASTM D 2487 Classification
36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200
Coarse Medium Fine Silt ClayFineCoarse
COBBLESBOULDERS GRAVEL SAND FINE GRAINED
SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER
Project No.:PROJECT NAME:
Philip Arnold ParkDATE OF TESTING:
Exploration Sample Depth (feet)Moisture (%)Fines (%)Description
B-2 7.5 26.7 SANDS-4 2.0
2294.01
9/1/2020
ASTM D 422, USDATest Results Summary
Zipper Geo Associates, LLC
Geotechnical and Environmental Consultants
0
10
20
30
40
50
60
70
80
90
100
0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS
GRAIN SIZE ANALYSIS
Comments: ASTM D 2487 Classification
36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200
Coarse Medium Fine Silt ClayFineCoarse
COBBLESBOULDERS GRAVEL SAND FINE GRAINED
SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER
Project No.:PROJECT NAME:
Philip Arnold ParkDATE OF TESTING:
Exploration Sample Depth (feet)Moisture (%)Fines (%)Description
B-6 2.5 7.4 SANDS-2 9.0
2294.01
9/1/2020
ASTM D 422, USDATest Results Summary
Zipper Geo Associates, LLC
Geotechnical and Environmental Consultants
0
10
20
30
40
50
60
70
80
90
100
0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS
GRAIN SIZE ANALYSIS
Comments: ASTM D 2487 Classification
36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200
Coarse Medium Fine Silt ClayFineCoarse
COBBLESBOULDERS GRAVEL SAND FINE GRAINED
SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER
Project No.:PROJECT NAME:
Philip Arnold ParkDATE OF TESTING:
Exploration Sample Depth (feet)Moisture (%)Fines (%)Description
B-6 5.0 4.4 SANDS-3 7.0
2294.01
9/1/2020
ASTM D 422, USDATest Results Summary
Zipper Geo Associates, LLC
Geotechnical and Environmental Consultants
0
10
20
30
40
50
60
70
80
90
100
0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS
GRAIN SIZE ANALYSIS
Comments: ASTM D 2487 Classification
36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200
Coarse Medium Fine Silt ClayFineCoarse
COBBLESBOULDERS GRAVEL SAND FINE GRAINED
SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER
Project No.:PROJECT NAME:
Philip Arnold ParkDATE OF TESTING:
Exploration Sample Depth (feet)Moisture (%)Fines (%)Description
B-6 7.5 14.8 SANDS-4 1.4
2294.01
9/1/2020
ASTM D 422, USDATest Results Summary
Zipper Geo Associates, LLC
Geotechnical and Environmental Consultants
0
10
20
30
40
50
60
70
80
90
100
0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS
GRAIN SIZE ANALYSIS
Comments: ASTM D 2487 Classification
36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200
Coarse Medium Fine Silt ClayFineCoarse
COBBLESBOULDERS GRAVEL SAND FINE GRAINED
SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER
Project No.:PROJECT NAME:
Philip Arnold ParkDATE OF TESTING:
Exploration Sample Depth (feet)Moisture (%)Fines (%)Description
B-7 5.0 16.8 Loamy SANDS-3 13.3
2294.01
9/1/2020
ASTM D 422, USDATest Results Summary
Zipper Geo Associates, LLC
Geotechnical and Environmental Consultants
Am Test Inc.
13600 NE 126TH PL
Suite C
Kirkland, WA 98034
(425) 885-1664
www.amtestlab.com
Professional
Analytical
Services
ANALYSIS REPORT
ZIPPER GEO ASSOCIATES, LLC Date Received: 09/01/20
19019 36TH AVENUE W Date Reported: 9/15/20
LYNNWOOD, WA 98036
Attention: DAVE WILLIAMS
Project Name: PHILIP ARNOLD PARK
Project #: 2294.01
All results reported on an as received basis.
_________________________________________________________________________________________________
AMTEST Identification Number 20-A013873
Client Identification TP-2, S-1A
Sampling Date 08/27/20, 09:15
Conventionals
PARAMETER RESULT UNITS Q D.L.METHOD ANALYST DATE
Cation Exchange Capacity 5.4 meq/100g 0.5 SW-846 9081 JDR 09/14/20
Miscellaneous
PARAMETER RESULT UNITS Q D.L.METHOD ANLST DATE
Organic Matter 2.0 %SM 2540G DM 09/08/20
_________________________________________________________________________________________________
AMTEST Identification Number 20-A013874
Client Identification TP-2, S-1B
Sampling Date 08/27/20, 09:20
Conventionals
PARAMETER RESULT UNITS Q D.L.METHOD ANALYST DATE
Cation Exchange Capacity 5.2 meq/100g 0.5 SW-846 9081 JDR 09/14/20
ZIPPER GEO ASSOCIATES, LLC
Project Name: PHILIP ARNOLD PARK
AmTest ID: 20-A013874
Miscellaneous
PARAMETER RESULT UNITS Q D.L.METHOD ANLST DATE
Organic Matter 1.8 %SM 2540G DM 09/08/20
_________________________________________________________________________________________________
AMTEST Identification Number 20-A013875
Client Identification TP-3, S-1A
Sampling Date 08/27/20, 09:50
Conventionals
PARAMETER RESULT UNITS Q D.L.METHOD ANALYST DATE
Cation Exchange Capacity 3.7 meq/100g 0.5 SW-846 9081 JDR 09/14/20
Miscellaneous
PARAMETER RESULT UNITS Q D.L.METHOD ANLST DATE
Organic Matter 1.3 %SM 2540G DM 09/08/20
_________________________________________________________________________________________________
AMTEST Identification Number 20-A013876
Client Identification TP-3, S-1B
Sampling Date 08/27/20, 09:50
Conventionals
PARAMETER RESULT UNITS Q D.L.METHOD ANALYST DATE
Cation Exchange Capacity 4.2 meq/100g 0.5 SW-846 9081 JDR 09/14/20
Miscellaneous
PARAMETER RESULT UNITS Q D.L.METHOD ANLST DATE
Organic Matter 1.5 %SM 2540G DM 09/08/20
_________________________________
Kathy Fugiel
President