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ENGINEERING REPORT
TECHNICAL INFORMATION REPORT
FAMILY FIRST COMMUNITY CENTER
RENTON, WA
November 4, 2019
PREPARED FOR:
City of Renton
1055 South Grady Way
Renton, WA 98057
PREPARED THROUGH:
City of Renton
1055 South Grady Way
Renton, WA 98057
PREPARED BY:
COUGHLIN PORTER LUNDEEN
801 Second Avenue, Suite 900
Seattle, WA 98104
P 206.343.0460
CONTACT / Keith Kruger, P.E.
May 8, 2020
SURFACE WATER UTILITY
jfarah 07/07/2020APPROVED
07/08/2020 msippo
DEVELOPMENT ENGINEERING DIVISION
i
Technical Information Report
Renton School District
Coughlin Porter Lundeen
Project No. C180040-01
May 8, 2020
TABLE OF CONTENTS
I PROJECT OVERVIEW ................................................................................................................................ 1
FIGURES .......................................................................................................................................................... 1
GENERAL DESCRIPTION .............................................................................................................................. 1
EXISTING CONDITIONS ................................................................................................................................. 1
PROPOSED CONDITIONS ............................................................................................................................. 2
II. CONDITIONS AND REQUIREMENTS SUMMARY ..................................................................................... 3
CORE REQUIREMENTS: ................................................................................................................................ 3
SPECIAL REQUIREMENTS: ........................................................................................................................... 3
PROJECT-SPECIFIC REQUIREMENTS: ....................................................................................................... 4
III. OFF-SITE ANALYSIS .................................................................................................................................. 5
TASK 1 – STUDY AREA DEFINITION AND MAPS ........................................................................................ 5
TASK 2 - RESOURCE REVIEW ...................................................................................................................... 5
TASK 3 - FIELD INSPECTION ........................................................................................................................ 6
TASK 4 - DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS .................................... 7
TASK 5 – MITIGATION OF EXISTING OR POTENTIAL PROBLEMS .......................................................... 7
UPSTREAM ANALYSIS ................................................................................................................................... 7
CONCLUSION .................................................................................................................................................. 8
IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ..................................... 9
EXISTING SITE HYDROLOGY (PART A) ...................................................................................................... 9
DEVELOPED SITE HYDROLOGY (PART B) ................................................................................................. 9
PERFORMANCE STANDARDS AND FLOW CONTROL SYSTEM (PARTS C) ........................................10
FLOW CONTROL BEST MANAGEMENT PRACTICES (PART D) .............................................................10
WATER QUALITY SYSTEM (PART E) .........................................................................................................11
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ................................................................................ 13
CONVEYANCE STANDARDS.......................................................................................................................13
ON-SITE CONVEYANCE SYSTEMS ............................................................................................................13
VI. SPECIAL REPORTS AND STUDIES ........................................................................................................ 16
VII. OTHER PERMITS ...................................................................................................................................... 17
VIII. CSWPPP ANALYSIS AND DESIGN ......................................................................................................... 18
EROSION AND SEDIMENT CONTROL ANALYSIS AND DESIGN (PART A) ...........................................18
SWPPS PLAN DESIGN (PART B) ................................................................................................................19
IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ............................ 20
CITY OF RENTON BOND QUANTITY WORKSHEET .................................................................................20
FLOW CONTROL AND WATER QUALITY FACILITY SUMMARY SHEET AND SKETCH .......................20
DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FLOW CONTROL AND WATER
QUALITY FACILITIES ....................................................................................................................................20
ii
DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FLOW CONTROL BMPS ..................20
X. OPERATION AND MAINTENANCE MANUAL ......................................................................................... 21
APPENDIX A – FIGURES .................................................................................................................................. 22
FIGURE 1 – TIR WORKSHEET ....................................................................................................................22
FIGURE 2 – VICINITY MAP ...........................................................................................................................22
FIGURE 3 – EXISTING SITE CONDITIONS ................................................................................................22
FIGURE 4 – PROPOSED SITE CONDITIONS .............................................................................................22
FIGURE 5 – DRAINAGE BASIN MAP ...........................................................................................................22
FIGURE 6 – 100-YR FLOODPLAIN MAP .....................................................................................................22
FIGURE 7 – AQUIFER RECHARGE AREA MAP ........................................................................................22
FIGURE 8 – OFF-SITE DRAINAGE ANALYSIS MAP ..................................................................................22
FIGURE 8A –OFF-SITE DRAINAGE TABLE ................................................................................................22
FIGURE 9 – COAL MINE HAZARD AREA....................................................................................................22
FIGURE 10 – SOILS MAP .............................................................................................................................22
FIGURE 10A – SOILS MAP TABLE ..............................................................................................................22
FIGURE 11 – UPSTREAM BASIN DELINEATION MAP ..............................................................................22
FIGURE 12 – TESC PLAN .............................................................................................................................22
APPENDIX B – ENGINEERING CALCULATIONS ............................................................................................ 23
APPENDIX C – CSWPPP ................................................................................................................................... 24
APPENDIX D – OPERATIONS AND MAINTENANCE MANUAL...................................................................... 25
APPENDIX E – FACILITIES SUMMARY AND DECLARATIONS OF COVENANT .......................................... 26
LIST OF TABLES
TABLE 1 - DEVELOPED SITE CONDITIONS AREA BREAKDOWN ................................................ 2
TABLE 2 - EXISTING SITE CONDITIONS AREA BREAKDOWN ..................................................... 9
TABLE 3 – SUB-BASIN AREAS .................................................................................................. 10
TABLE 3 – DETENTION FACILITY SUMMARY ............................................................................ 10
FAMILY FIRST COMMUNITY CENTER
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I PROJECT OVERVIEW
FIGURES
Refer to Appendix A for figures.
GENERAL DESCRIPTION
The following Technical Information Report (TIR) provides the technical information and design analysis
required for developing the Stormwater Drainage and Temporary Erosion and Sedimentation Control
(TESC) Plans for the Family First Community Center. The stormwater design for the project is based on the
requirements set forth by the 2017 City of Renton Surface Water Design Manual (2017 CRSWDM)
The Family First Community Center is located at 16022 116th Avenue SE, Renton WA 98058 (See Figure 2
– Vicinity Map) adjacent to the existing Cascade Elementary School. The property is owned by Renton
School District and is bound by an easement to Pacific Northwest Pipe Line Corporation to the north, 116th
Avenue SE to the west and single-family residences to the east and south. The project is located on a 14.9
acre parcel and the parcel number 152823059034. The project is in the NW ¼ of Section 28, Township 23
North, Range 5 East, Willamette Meridian. The project is currently pursuing a short plat for the development
area, which is 2.51 acres, to separate the Family First Community Center property from the existing
Cascade Elementary School property.
The project consists of the construction of a new one-story community recreational center that is 27,000
square feet and approximately 120 surface parking stalls. The community center will include a new
gymnasium, activity rooms, gathering places, offices, a kitchen, parking lot and associated landscaping and
sidewalks. An existing biofiltration swale and associated storm piping will be removed to accommodate the
new development. The project will be removing the existing water quality treatment facility for the Cascade
Elementary School (biofiltration swale) and replacing the facility with a Modular Wetland System to treat the
pollution generating runoff from the existing site. The project will result in 2.03 -acres of new or replaced
impervious area and 0.48-acres of new or replaced pervious area within the parcel. The total project area is
2.51 acres.
EXISTING CONDITIONS
The existing site consists of an 0.6-acre parking lot, a grass field and an existing biofiltration swale on the
southern side of the existing Cascade Elementary School site. The project site is fully developed with
existing stormwater facilities. The topography generally slopes from west to east with the project site outfall
located on the southeast corner of the site. (See Figure 3 – Existing Site Conditions).
The project high point is located at the western property line, at elevations of 465 and 466 respectively. The
existing low point is located at the southeast corner of the site at an elevation of 452 feet. The overall drop
across the site from the northwest corner down to the southeast corner is 13 feet.
Stormwater runoff flows from west to east. Stormwater runoff from the existing site consists of surface,
shallow, and piped flow to the existing biofiltration swale located on the south side of the site, which then
discharges to the existing stormwater system at the southeast corner of the site. The upstream area from
the existing Cascade Elementary School and properties to the west side of 116th Avenue is routed through
our site via the onsite bypass (see Figure 11 – Upstream Delineation Basin Map). Based on the existing
contours from survey and City of Renton GIS, there are no onsite flows from the southern properties.
There are no critical areas within with the existing site. The adjacent street is 116th Avenue SE located to the
west. 116th Avenue SE is generally flat but slopes down to the south at slopes ranging from 0 percent to 0.5
percent. It is developed with a sidewalk, curb, landscape strip and catch basins on the side adjacent to the
site.
The Soils Conservation Service maps the soils as generally Arents, Alderwood material (See figure 8 – Soil
Map) . A geotechnical analysis of the site was performed by The Riley Group, Inc (RGI) and published in a
report dated June 8, 2018. The RGI investigation found “The site is underlain by up to 11 feet of fill
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comprised of loose to medium dense silty sand with varying amounts of gravel over medium dense to very
dense silty sand with varying amounts of gravel, and localized silty sand, sandy gravel, and sand with some
silt and gravel.”
PROPOSED CONDITIONS
The proposed project consists of the construction of a new one-story community recreational center that is
27,000 square feet and approximately 120 surface parking stalls (see Figure 4 – Proposed Site Conditions).
The community center will include a new gymnasium, activity rooms, gathering places, offices, a kitchen,
parking lot and associated landscaping and sidewalks. The proposed project, including frontage
improvements, will result in 2.08 acres of new or replaced impervious surface, which triggers a “Full
Drainage Review” (2017 City of Renton Surface Water Manual 1.1.2.4) and the analysis of all “Core” and
“Special” requirements. Please see Table 1 – Developed Site Conditions Area breakdown for a summary of
the proposed land coverages.
TABLE 1 - DEVELOPED SITE CONDITIONS AREA BREAKDOWN
LAND COVER AREA (ACRES) DESCRIPTION
Impervious Surface 2.08 Parking and drive aisles, building, and sidewalk
Pervious Surface (Landscape) 0.49 Lawn and landscape area
Total Disturbed Area 2.57 Disturbed area
% Impervious Area 80.9%
The Core Requirements include Minimum Requirement #3 which requires flow control for the total disturbed
area. The detention facilities are to be modeled using MGSFlood software with 15-minute time steps. Two
detention facilities will provide flow control: an SC-740 Stormtech Chamber System and a MC-3500
Stormtech Chamber System. Both Stormtech Chamber systems will discharge to the existing storm system
located in the southeast corner of the site.
The Core Requirements also include Minimum Requirement #8 which requires water quality treatment for
pollution generating surfaces. Water quality treatment will be provided by a proprietary Modular Wetland
System and bioretention that will be used to mitigate pollution generating areas. For Core Requirement #9:
On-Site BMPs, Flow Control Best Management Practices (FCBMPs), since the project has over 80%
impervious surface coverage the project does not need to apply FCBMPs for any target surface area,
according to table C1.3.A of the 2017 RSWDM. See Section IV for further detail for the flow control and
water quality systems.
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II. CONDITIONS AND REQUIREMENTS SUMMARY
This section addresses the requirements set forth by the Core and Special Requirements listed in Chapter 1
of the City of Renton Surface Water Design Manual.
CORE REQUIREMENTS:
1. Discharge at the Natural Location (1.2.1): Stormwater runoff from the existing site discharges to the
existing City of Renton Stormwater system via surface flow and via a ditch and pipe conveyance system
on the southeast corner of the site. The existing site contains a biofiltration swale that collects runoff
from the site via surface and piped flow, which then discharges to the City’s existing stormwater system.
In the developed condition, stormwater runoff will continue to discharge to the City’s stormwater system
via surface and pipe flow. The development will be installing a new structure over the existing
stormwater system at the natural discharge location, where the project will be tying into the existing
stormwater system.
2. Off-site Analysis (1.2.2): A Level 1 analysis of the upstream and downstream flow paths for the
project was performed on September 9, 2018 and is detailed in Section III. This analysis showed that no
downstream problems will occur by the construction of the project.
3. Flow Control (1.2.3): Level II flow control requires the project to meet flow durations for forested
conditions. This requirement will be met by providing two Stormtech Chamber detention systems.
Further information is presented in Section IV of this report.
4. Conveyance System (1.2.4): Closed pipe systems will be provided for on-site stormwater
conveyance. Further details are provided in Section V.
5. Erosion and Sedimentation Control (1.2.5): Erosion and Sediment Control (ESC) measures will be
provided during construction to address the specific conditions at the site. Further details can be found
in Section VIII.
6. Maintenance and Operations (1.2.6): The proposed storm drainage system will be owned, operated
and maintained by the City of Renton. Further details can be found in Section X.
7. Financial Guarantees and Liability (1.2.7): The Owner and Contractor will obtain all necessary
permits prior to the beginning of construction.
8. Water Quality (1.2.8): The project is considered a “commercial” project and drains to the City of
Renton Stormwater system, therefore, Enhanced Basic water quality is required for this project.
Enhanced Basic water quality treatment will be addressed using a proprietary Modular Wetland System
and bioretention to treat runoff from all target surfaces. Further details are provided in Section IV of this
report.
9. Flow Control BMPs (1.2.9): According to table C1.3.A of the 2017 RSWDM, projects that has over
80% of impervious surface coverage do not need to apply FCBMPs. Since the project has 81%
impervious surface coverage, the project is not required to implement FCBMPs.
SPECIAL REQUIREMENTS:
1. Other Adopted Area-Specific Requirements (1.3.1):
· Critical Drainage Areas (CDAs): The project site is not located within any Critical Drainage Areas.
· Master Drainage Plans (MDPs): There are no known master drainage plans covering this project
site.
· Basin Plans (BPs): The project is located within the Lower Cedar River Drainage Basin (see Figure
5 – Drainage Basin Map). The basin plan does not include any special drainage requirements.
· Stormwater Compliance Plans (SWCPs): There are no Stormwater Compliance Plans that are
applicable to this project.
· Lake Management Plans(LMPs): There are no Lake Management Plans that are applicable to this
project.
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· Shared Facility Drainage Plans(SFDPs): There are no shared Facility Drainage Plans that are
applicable to this project.
2. Flood Hazard Area Delineation (1.3.2): The project site is not located within the 100-year floodplain
(see Figure 6 – 100-yr Floodplain Map).
3. Flood Protection Facilities (1.3.3): The project will not rely on or modify an existing flood protection
facility.
4. Source Controls (1.3.4): The project will be providing spill control for catch basins that are directly
upstream of the detention systems to meet source control requirements.
5. Oil Control (1.3.5): Vehicle use and traffic concentration on the site will not reach levels that require oil
control facilities. The developed new plus replaced pollution generating surface area does not exceed
the high use site threshold amount.
6. Aquifer Protection Area (1.3.6): Not applicable. Project site nor downstream flow path located within 1
mile from an Aquifer Recharge Area (See Figure 7 – Aquifer Recharge Area Map).
PROJECT-SPECIFIC REQUIREMENTS:
There are no additional requirements for the project. Design and construction will abide by requirements set
forth in these documents and the 2017 City of Renton Surface Water Design Manual.
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III. OFF-SITE ANALYSIS
TASK 1 – STUDY AREA DEFINITION AND MAPS
This off-site analysis examines the stormwater systems upstream and downstream of the Family First
Community Center project, located at 16022 116th Avenue SE, Renton WA, 98058. The Family First
Community Center project consists of the construction of a new recreational center that is approximately
27,000 square feet and will include a new gymnasium, activity rooms, gathering spaces, and a
demonstration kitchen. The community center project will construct 120 surface parking lot stalls and
associated sidewalks and landscape areas. The existing site is roughly 2.51 acres with about 0.46 acres of
impervious area and is not constrained by any critical areas or corresponding buffers. The proposed project
will add or replace roughly 2.03 acres of impervious surface and will not convert any square feet of
impervious area to landscape. The Figure 2 - Vicinity Map, Figure 8 - Off-Site Drainage Analysis Map, and
Figure 8A – Off-Site Drainage Analysis Table in the Appendix depict the location of the project site and the
basins being analyzed.
TASK 2 - RESOURCE REVIEW
a) Adopted Basin Plans:
According to the King County Drainage Basin iMap, this project is in the Lower Cedar River
Drainage Basin, as depicted in Figure 5 - Drainage Basin Map. The Lower Cedar River Basin and
Nonpoint Pollution Action Plan, adopted in 1997, depicts basin boundaries that are slightly different
than the basin boundaries in the King County Drainage Basin iMap. According to the Lower Cedar
River Basin and Nonpoint Pollution Action Plan, there are not issues regarding potential flooding
erosion and water quality problems upstream nor one mile downstream of the project site, as of
1997.
b) Floodplain/Floodway FEMA Maps:
The project site nor the downstream flow path is not located within a Floodplain/floodway (FEMA).
See Figure 6 – 100-Year Floodplain
c) Other Off-site Analysis Reports:
No off-site analysis reports were available within one mile of the site as of September 2018.
d) Critical Areas:
· No Coal Mine Hazard Areas are mapped within the downstream flowpath (see Figure 9)
· Critical Wetland Areas are mapped within the downstream flowpath (see Figure 8)
· No Erosion Hazard Areas are mapped within the downstream flowpath (see Figure 8)
· No Landslide Hazard Areas are mapped within the downstream flowpath (see Figure 8)
· Steep Slope Hazard Areas are mapped within the downstream flowpath (see Figure 8)
· No Seismic Hazard Areas are mapped within the downstream flowpath (see Figure 8)
· No Critical Aquifer Recharge Areas are mapped within the downstream flowpath (see
Figure 7)
e) Soils Survey:
The soils that are expected to underlay the project site have been classified by the USDA Natural
Resources Conservation Service (NRCS) as Arents, Alderwood material, 6 to 15 percent slopes (AmC).
See Figure 10 - Soils map.
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f) Wetland Inventory Map:
According to City of Renton GIS, wetlands are within the study area are identified on King County’s
of City of Renton’s iMap (see figure 8).
g) Section 303d List of Polluted Waters:
Not applicable to the study area.
h) City of Renton Erosion Maps and Landslide Maps: No Erosion or Landslide Hazards are included within
the study are for this Project. See Figure 8 – Off Site Drainage Analysis Map.
i) Other reports: Cascade Elementary School Portables Project TIR.
TASK 3 - FIELD INSPECTION
A Level 1 Downstream Analysis site visit was made on 9/6/2018 under dry conditions. Total precipitation for
9/6/2018 was 0 inches. No rainfall occurred on the day prior to the site visit. Results of the field inspection
are shown in the Off-Site Drainage Systems Table attached to Figure 8 - Off-Site Drainage Analysis Map in
the Appendix.
1. Investigate any problems reported or observed during the resource review.
· No problems were reported or observed during the resource review.
2. Locate all existing/potential constrictions or lack of capacity in the existing drainage system.
· No constrictions or lack of capacity in the existing drainage system was observed.
3. Identify all existing/potential downstream drainage problems as defined in Section 1.2.2.1.
· No existing/potential downstream drainage problems were observed.
4. Identify existing/potential overtopping, scouring, bank sloughing, or sedimentation.
· No existing/potential overtopping, scouring, bank sloughing, or sedimentation was
observed.
5. Identify significant destruction of aquatic habitat or organisms (e.g., severe siltation, bank erosion,
or incision in a stream).
· No significant destruction of aquatic habitat or organisms was observed.
6. Collect qualitative data on features such as land use, impervious surfaces, topography, and soil
types.
· The land use of the project site is a school site that consists of approximately 30%
impervious area and sports fields to the east side. The conveyance system drains through
a residential area to the east before reaching 119th Avenue SE, where the road slopes
down to a catch basin before being conveyed farther east. The upstream basin was
delineated by determining what portion of the existing Cascade Elementary School site
drains to the existing bioswale and reviewing existing contours from the City of Renton GIS
to see which portions of the residential area to the west of 116th avenue drains onto the site
(See Figure 11 – Upstream Basin Delineation Map). The upstream basin, that will bypass
our detention system, was determined to be 10.09 acres (see Figure 11) The existing
bioswale will be replaced as a part of the proposed development and the same basin
draining to the bioswale is the upstream basin for the proposed project. Based on the
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survey, City of Renton GIS and observations on site, no other upstream basin was
delineated.
7. Collect information on pipe sizes, channel characteristics, drainage structures, and relevant critical
areas (e.g., wetlands, streams, steep slopes).
· See Figure 8 for information on pipe sizes and drainage structures. No critical areas were
observed.
8. Verify tributary basins delineated in Task 1.
· Based on the topography onsite, the basin delineation based on the survey and COR maps
was confirmed (see figure 11 for more information on upstream delineation).
9. Contact neighboring property owners or residents in the area about past or existing drainage
problems and describe these in the report (optional).
· This requirement is not applicable for this project.
10. Note the date and weather conditions at the time of the inspection.
· The site visit occurred on September 6, 2018. The weather was sunny, and temperature
was 65 degrees.
TASK 4 - DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS
See Figure 8 for a map of the downstream drainage system. The site currently discharges from a catch
basin at the southeast corner of the site located directly downstream of an existing bioswale and then
through a series of catch basins in residential streets. This catch basin and bioswale will be replaced as a
part of the proposed development. Downstream of the replaced catch basin, stormwater is conveyed
approximately 200 feet through an existing 15” pipe to an existing type 1 catch basin located at the
southeast corner of the Cascade Elementary School property. Stormwater is then conveyed roughly 320
feet to a type two catch basin located in 119th Ave SE, which is adjacent to the property. Stormwater is then
conveyed approximately 300 feet through a 24” concrete pipe at approximately 2% to another type two
catch basin located in 120th Ave SE. From here stormwater is directed through a 24” concrete pipe at 2%
slope to a type two catch basin located in 121st Ave SE, approximately 300 feet downstream. The downhill
discharge point of the offsite drainage system is located at Ginger Creek, approximately one-half mile
downstream. Existing downstream drainage infrastructure is located near wetland areas. See Off-Site
Drainage System (attached to Figure 8) for more information regarding the downstream drainage system.
TASK 5 – MITIGATION OF EXISTING OR POTENTIAL PROBLEMS
No existing or potential problems were observed during the downstream analysis.
UPSTREAM ANALYSIS
Based on survey and the City of Renton GIS, 10.09 acres of upstream residential and ROW area currently
flows to the existing bioswale located onsite (see Figure 11 for a breakdown of impervious and pervious
areas). The upstream basin was delineated by determining what portion of the existing Cascade Elementary
School site drains to the existing bioswale and reviewing existing contours shown on the City of Renton GIS.
This upstream area also includes a portion of the right-of-way, including a portion of 116th Avenue. The
existing bioswale will be replaced as a part of the proposed development and the same basin draining to the
bioswale is the upstream basin for the proposed project. This upstream basin will be treated for water quality
and will bypass the detention system. Based on the survey and observations on site, no other upstream
basin was delineated. See Figure 11 for the upstream basin delineation.
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CONCLUSION
Based on the observations made during the Level 1 downstream analysis that was performed on 9/6/2018,
no existing or potential downstream drainage issues such as flooding, overtopping, or erosion were evident.
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IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND
DESIGN
EXISTING SITE HYDROLOGY (PART A)
The existing site consists of a park with a grass field, parking lot and landscaping area (See Figure 3 –
Existing Site Conditions). The site slopes in a southeasterly direction with drainage described in Section III
Downstream Analysis. These conditions are summarized in Table 2 below.
TABLE 2 - EXISTING SITE CONDITIONS AREA BREAKDOWN
LAND COVER AREA
(ACRES) DESCRIPTION MODELLED AS
Impervious Area 0.52 Existing parking lot Till Forest
Pervious & Landscape 2.05 Grass Field and Native vegetation Till Forest
Total Project Area 2.57
% Impervious Area 30.7%
The existing site contains a biofiltration swale that has a large tributary off-site area. The upstream area is
approximately 10 acres of residential area and a portion of 116th avenue. See figure 11 for more information.
DEVELOPED SITE HYDROLOGY (PART B)
The developed site will increase the amount of impervious area to 2.08 acres and the remaining site area
with be pervious landscaping or bioretention and green roof areas. (See Figure 4 – Proposed Site
Conditions). The area impacted by the development is 2.57 acres.
The project will be using two Stormtech Chamber detention systems to meet the project’s flow control
requirements. By dividing into two different size chamber systems, the project can utilize the existing
topography to minimize earthwork. However, the project will only have one discharge location.
The site has been divided into two separate sub-basins, one for each of the Stormtech Chamber detention
systems. The table below provides a breakdown of the areas of each of the sub-basins. See Figure 4 –
Proposed Site Conditions for more information.
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TABLE 3 – SUB-BASIN AREAS
SUB-
BASIN LAND COVER AREA (ACRES) DESCRIPTION MODELLED AS
East Impervious Area 0.70 Parking lot, Sidewalk
Impervious
Pervious Area 0.14 Landscaping, Planters Till Grass
East Flow
Through Impervious Area 0.11* Existing parking lot
Impervious
West Impervious Area 1.38 Parking lot, Sidewalk, Roof
Impervious
Pervious Area 0.16 Landscaping, Planters Till Grass
Bypass Pervious Area 0.18 Landscaping Till Grass
Total Project Area 2.57
% Impervious
Area
80.9%
*flow through area not included in total project area but is included in detention calculations.
PERFORMANCE STANDARDS AND FLOW CONTROL SYSTEM (PARTS C)
Level II flow control (conservation flow control assuming historic site conditions) is required for this project.
Level II flow control requires the proposed discharge durations to match the predeveloped durations for the
range of predeveloped discharge rates from 50 percent of the 2-year peak flow up to the full 50-year peak
flow. MGSFlood software was used to size the detention facilities in compliance with the CRSWDM
standards. The calculations for the detention facilities are included in Appendix B.
Runoff from the site will be detained in two detention facilities, an SC-310 Stormtech Chamber system and a
MC-3500 Stormtech Chamber system. The proposed detention volumes are summarized in Table 3 below.
TABLE 3 – DETENTION FACILITY SUMMARY
DETENTION FACILITY PROVIDED
[CF]
REQUIRED
(CF)
SC-310 StormTech Chambers 18,907 18,907
MC-3500 StormTech Chambers 29,259 29,259
FLOW CONTROL BEST MANAGEMENT PRACTICES (PART D)
According to table C1.3.A of the 2017 RSWDM, projects that has over 80% of impervious surface coverage
do not need to apply FCBMPs. Since the project has 81% impervious surface coverage, the project is not
required to implement FCBMPs. See below for table C1.3.A from the 2017 CRSWDM.
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WATER QUALITY SYSTEM (PART E)
Under Core Requirement #8 the project is required to provide Enhanced Basic water quality treatment for
the pollution generating surfaces. To meet the water quality standards, the project will treat pollution
generating surfaces by using one proprietary Modular Wetland Systems (MWS) and one bioretention cell.
Water quality design calculations are provided in Appendix B.
The Family First Community Center project will be removing the existing biofiltration swale that is currently
being used as a water quality treatment facility for the Cascade Elementary School site. One of the
proposed Modular Wetland System will be used to treat the pollution generating runoff from the existing
Cascade Elementary School site in replacement of the biofiltration swale.
The other Modular Wetland System will be used to treat the pollution generating runoff from the proposed
pollution generating surfaces that will be constructed as a part of the Family First Community Center project
before discharging to the existing City of Renton stormwater system.
The MWSs are sized according to 2-year flow rates provided in the MGSFlood report in Appendix B. These
water quality flow rates are based on the total upstream area to each system. These flow rates are then
provided to BioClean who provide the required MWS size to meet water quality treatment. They are located
downstream of the detention facilities and so are sized to treat the full 2-year release rate post detention.
Runoff enters each MWS vault via pipe. In the vault, trash, sediment and debris are separated before runoff
enters the pre-filter cartridges. The pre-filter cartridges utilize a media filter material which removes over 80
percent of total suspended solids and over 90 percent of hydrocarbons. After pre-filtering, the runoff enters a
chamber with a patented wetland media. The wetland media removes any phosphorous in the water. The
MWSs have an internal bypass weir for large storm events (up to the 100-year event). See table below for
water quality flow rates used to size the MWS systems. As shown in the plans. Both systems are sized to be
MWS L-4-6.
The water quality flow rate used to design the north MWS that is in place for the upstream bypass, is subject
to a correction factor (k) as discussed in section 6.2.1 of the 2017 CRSWDM. The correction factor is based
on the 6-month precipitation depth which can be found by taking 72% of the 2-year 24 hour precipitation
depth. Using the 2-year 24-hour isopluvial map, 72% of the 2-year 24-hour precipitation depth for the project
is 1.44 inches. Per table 6.2.1.A in the 2017 CRSWDM, the correction factor (k) for this 6-month
FAMILY FIRST COMMUNITY CENTER
12
precipitation depth is can be found be linear interpolation. See calculation and table below for the corrected
water quality flow rate used to design the north MWS.
Per table 6.21.A of the 2017 CRSWDM:
k = 2.477(P72%, 2-yr) – 0.0352
k = 2.477 (1.44 in) – 0.0352 = 3.53 in
TABLE 4 – MWS SUMMARY
MWS SYSTEM WATER QUALITY
FLOW RATE
[CFS]
CORRECTION
FACTOR (K)
CORRECTED
2-YEAR
WATER
QUALITY FLOW
RATE [CFS]
North MWS (Upstream Bypass) 0.15 3.53 0.53
South MWS (downstream MC-3500
Stormtech Chambers)
0.045 - -
The bioretention cell is modeled in MGSFlood and sized to remove at least 91% percent of pollutants per
requirements in section 6.2 of the 2017 CRSWDM. The bioretention is designed to have 18” of bioretention
soil, 6” of live storage, 6” of freeboard, with 3:1 side slopes and 5 weir walls to separate the bioretention into
six cells. Due to the amount of tributary area, six bioretention cells are required. Based on the MGSFlood
report, the bioretention is meeting the water quality requirements by removing over 91% of pollutants. See
Appendix C for more information.
Spill Control is required for projects constructing or replacing onsite pipe systems that receive runoff from
pollution generating surfaces such as parking lots (Section 1.2.4.3 of the CRSWDM). Spill control will be
provided by a tee with a cap to prevent floatables from entering the drainage system located in the catch
basin immediately upstream of the flow control system.
FAMILY FIRST COMMUNITY CENTER
13
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
CONVEYANCE STANDARDS
The conveyance systems have been designed to meet the requirements set forth in Chapter 4 of the 2017
CRSWDM. The requirements and the way the design will meet them are presented, below.
1. Facilities must convey the 100-year flow without overtopping the crown of the roadway, flooding
buildings, and if sheet flow occurs it must pass through a drainage easement. Facilities will be
designed to convey the 100-year storm without affecting surrounding infrastructure. No sheet flow to
neighboring properties is expected to occur.
2. New pipe systems and culverts must convey the 25-year flow. New pipe systems are designed to
convey the 25-year flow without overtopping structures.
3. Bridges must convey the 100-year flow and provide a minimum of two feet, varying up to six
feet, of clearance based on 25% of the mean channel width. This project will not construct bridges.
4. Drainage ditches must convey the 25-year flow with 0.5 feet of freeboard and the 100-year flow
without overtopping. This project will not construct drainage ditches.
5. Floodplain Crossings must not increase the base flood elevation by more than 0.01 feet and
shall not reduce the flood storage volume. Piers shall not be constructed in the FEMA floodway.
There are no floodplain crossings or piers associated with this project.
6. Stream Crossings shall require a bridge for Class 1 Streams that does not disturb or banks. For
Type 2 and Type 3 steams, open bottom culverts or other method may be used that will not
harm the stream or inhibit fish passage. There are no stream crossings associated with this project.
7. Discharge at natural location is required and produce no significant impacts to the downstream
property. This project will provide Level II flow control and will discharge at the natural location. The
flow control facilities will reduce the rate of flow discharging from the existing site.
ON-SITE CONVEYANCE SYSTEMS
Existing Conditions
The existing conveyance system consists of catch basins, storm pipes and a biofiltration swale. The existing
biofiltration swale and some of the existing catch basins and storm pipes that are located within the
development area will be removed and new catch basins and storm pipes will be installed.
Developed Conditions
The developed on-site conveyance system will consist of catch basins and storm pipes. The existing storm
pipe that conveys runoff from the existing Cascade Elementary school site that will be removed to construct
the new Family First Community Center building will be rerouted to the existing conveyance system. The
conveyance system conveys runoff from the redevelopment and upstream areas to the existing conveyance
system. Since the upstream bypass will be rerouted through the project site, the proposed storm system is
designed and sized to convey the runoff from the entire upstream basin.
There will be one connection point to the existing storm system. The connection point to the existing system
is in the southeast corner of the site, where the Family First project and the rerouted stormwater from the
Cascade ES site will discharge. Peak flow rates for the proposed conveyance systems were calculated
using the Rational Method. The hydraulic grade line was calculated using the Direct Step Backwater
Method. Conveyance calculations are provided in Appendix B.
FAMILY FIRST COMMUNITY CENTER
14
Conveyance and Backwater Analysis:
The conveyance analysis for this development has been performed using Autodesk Storm and Sanitary
Analysis (SSA) for each sub-basin within the site, following the 2017 City of Renton Surface Water Design
Manual standards for conveyance analysis. This analysis uses the storm network designed in Civil 3D to
perform the conveyance analysis and backwater calculations for the designed storm system. From the Civil
3D model, SSA can extract pipe size, length, slope, and invert elevations, along with the rim elevation for
each structure.
In order to meet City of Renton requirements for conveyance analysis, settings within SSA were updated to
reflect the correct analysis options. Because the tributary area is less than 10 acres and located upstream of
the detention facility, Table 3.2- Acceptable Uses of Runoff Computation Methods in the CRSWDM states
that analysis should be performed using the Modified Rational Method, the time of concentration should be
6.3 minutes for all runs, and Link Routing is set to “Hydrodynamic” for SSA to calculate backwater analysis
within the model. These system settings can be seen in Figure 12 - SSA Settings within Appendix B.
With SSA set to use the Modified Rational Method (QR=C*IR*A), the “C”, “IR” and “A” values must be entered
into the program for it to calculate the QR for the proposed system. The first step in these calculations was to
find the catchment area in acres for each structure on site, which can be seen in Figure 11 – Conveyance
Areas within Appendix B, within this section. These areas are then input as the “A” within the characteristics
for each structure in SSA. With the catchment areas calculated for each structure, the “C” values could then
be found for each of those sub-basins. This value was calculated by first finding the total pervious and
impervious surface area for each sub-basin. Using a “C” value of 0.25 for pervious lawn areas, and 0.90 for
impervious pavement (Table 3.2.1.A – Runoff Coefficients, 2017 CRSWDM), a weighted “C” value was
found for each area and entered into SSA for each sub-basin.
The final value to input for SSA to use the Modified Rational Method is “IR”, which is input as a system
setting, rather than a characteristic for each sub-basin. To do this, an IDF curve is created within SSA for the
design storm, which in this case is the 25-year 24-hour storm. Using the equations within section 3.2.1 –
Rational Method of the CRSWDM for “IR” (IR = PR * iR, where iR = aR * TC - bR) the IDF curve could be created
within SSA. To begin, PR is calculated to be 3.4 using Figure 3.2.1.D – 25-Year 24-Hour Isopluvials (See
Figure 42 – 25-yr, 24-hr Isopluvial Map in Appendix B). The time of concentration, “TC”, is set at a constant
6.3 minutes, while aR and bR are values found in Table 3.2.1.B – Coefficients for the Rational Method “iR”
Equation within the CRSWDM, which are 2.66 and 0.65, respectively. Detailed calculations showing the
correlation between CRSWDM formulas and the SSA IDF curve can be seen below.
CRSWDM: IR = PR * aR * TC –bR = (3.4 in * 2.66 * 6.3 min -0.65) = 2.734 in/hr
SSA: i = B / (TC + D)E = (9.044 in) / (6.3 min + 0) .65 = 2.734 in/hr
A node referred to as an outfall is also an important part of computing a conveyance analysis within SSA.
This site has one outfall, representing the downstream point of connection to the existing conveyance
system. Outfalls within SSA are where initial tailwater elevations are input to conduct a backwater analysis.
Due to a lack of available information pertaining to the existing conveyance system, an initial tailwater
elevation was set to assume that the existing pipe is flowing full, which is a conservative estimate assuming
that if the system was designed to accommodate the full buildout of the school site, the pipe would not be
flowing full. Details for the site outfall can be found in the SSA results (Figure 15 – 25-yr, 24-hr Outfall
Analysis Results in Appendix B).
Results:
The results provided within SSA are broken into four tables, which are included in Appendix B. The first
table is a description of all pipes within the site conveyance system, including the length, slope, upstream
and downstream structures, entrance and exit losses, available capacity, and peak flow within each pipe. It
is important to note that pipes labeled as “Surcharged” and “> Capacity” are acceptable, because the City of
Renton requirement for the conveyance system states that the rim of each structure cannot be overtopped,
FAMILY FIRST COMMUNITY CENTER
15
therefore a surcharged pipe does not mean the requirement is not met (Figure 14 – 25-yr, 24-hr Pipe
Analysis Results Table in Appendix B).
The second table shows the results of the outfall for the site, stating the peak flow leaving the site, invert
elevation for the pipe at the point of connection, and the fixed water elevation, which in this case is set 24”
above the invert elevation, representing the full pipe (Figure 15 – 25-yr, 24-hr Outfall Analysis Results in
Appendix B).
The third table is a summary of every structure within the conveyance system. This table contains the rim
elevation for each structure, outlet pipe invert elevation, peak inflow, max HGL attained, and minimum
freeboard attained. Emphasis should be placed on the minimum freeboard attained. Values greater than
zero in this column demonstrate that the requirement not to overtop the rim of any structure has been met
(Figure 16 – 25-yr, 24-hr Structure Analysis Results in Appendix B).
The final table of results provided from SSA summarizes each sub-basin within the site including the area,
the name of the structure it drains to, the weighted C value for each sub-basin, rainfall intensity, and time of
concentration. See Figure 17 – 25-yr, 24-hr Subbasin Analysis Results, Appendix B. To accompany these
results, Figure 11 – Catchment areas (Appendix B) is a map showing the catchment areas used to calculate
the catchment area and C Value for each structure.
Also included within the results are profiles of the conveyance system. These profiles are created within
SSA and show each structure and pipe within the system with the max HGL. See Figure 18 – SSA Profile
Layout in Appendix B for clarification on which structures and pipes included in each profile.
Outfalls:
Energy dissipation of pipe outfalls is required per the CRSWDM Section 1.2.4.3. Since the conveyance
system will connect to an existing catch basin, an external drop connection will be used.
FAMILY FIRST COMMUNITY CENTER
16
VI. SPECIAL REPORTS AND STUDIES
1. Geotechnical Engineering Report. Renton, Washington. Prepared by The Riley Group, Incorporated on
June 8, 2018.
FAMILY FIRST COMMUNITY CENTER
17
VII. OTHER PERMITS
This project will require building and demolition permits from the City of Renton and an NPDES permit from
the Department of Ecology. The NPDES will include a SWPPP and a spill prevention and cleanup report
(included in the SWPPP). This project will also require a Developer Extension agreement from Soos Creek
Water and Sewer District.
FAMILY FIRST COMMUNITY CENTER
18
VIII. CSWPPP ANALYSIS AND DESIGN
This section lists the requirements that were met when designing the TESC plan for this site. The project will
be publicly bid and a contractor will be determined at a future date.
EROSION AND SEDIMENT CONTROL ANALYSIS AND DESIGN (PART A)
Erosion/Sedimentation Plan shall include the following:
1. Clearing Limits – Construction limits are delineated on the project erosion control plans and shall be
physically surveyed and marked on site.
2. Cover Measures – Contractor will use plastic sheeting, hydroseeding, and mulching to protect soils
from erosion.
3. Perimeter Protection – Temporary construction fencing will be used to delineate and protect the
project clearing limits and provide a secure site. Silt fencing and interceptor swales will be used to
prevent sediment-laden water from discharging from the site.
4. Traffic Area Stabilization – Stabilized construction entrances and a wheel wash will be used for traffic
area stabilization.
5. Sediment Retention – Site temporary erosion and sediment control plans will include baker tanks,
temporary sediment pond, and catch basin protection to provide sediment control.
6. Surface Water Collection – Interceptor swales will be used in the appropriate areas of the site to
collect stormwater runoff. The swales are then routed to the sediment pond and baker tanks.
7. Dewatering Control – Dewatering is not necessary for this site; therefore, no dewatering control
measures are implemented.
8. Dust Control – Soils will be appropriately sprinkled with water to limit airborne dust during dry weather.
9. Flow Control –Discharge from the baker tanks and sediment pond will be restricted and will therefore
serve as a flow control measure during construction.
10. Control Pollutants – The discharged runoff from the construction site will be monitored for turbidity and
pollutants before leaving the site.
11. Protect Existing and Proposed Flow Control BMPs – Proposed FCBMPs consist of bioretention.
The bioretention areas will be protected during construction.
12. Maintain BMPs – BMPs for the project will be monitored for effectiveness on a regular basis. The
Construction Stormwater Pollution Prevention (CSWPP) Supervisor will typically monitor the BMPs and
ensure they are repaired and replaced as necessary.
13. Manage the Project – The BMPs will be inspected maintained and repaired as needed to ensure their
intended performance. Site inspections and monitoring will be in accordance with the Construction
Stormwater General Permit, specific BMP conditions and the City of Renton requirements. The CSWPP
will be maintained and updated and any updates will be coordinated with the site inspector.
FAMILY FIRST COMMUNITY CENTER
19
SWPPS PLAN DESIGN (PART B)
See figure 12 – TESC Plan for more information.
See Appendix C for the CSWPPP.
FAMILY FIRST COMMUNITY CENTER
20
IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF
COVENANT
CITY OF RENTON BOND QUANTITY WORKSHEET
A Bond Quantity Worksheet is provided in Appendix E.
FLOW CONTROL AND WATER QUALITY FACILITY SUMMARY SHEET AND SKETCH
A Facility Summary sheet and sketch are provided in Appendix E.
DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FLOW CONTROL AND
WATER QUALITY FACILITIES
Declaration of Covenant for Stormwater Facilities is included in Appendix E of this report.
DECLARATION OF COVENANT FOR PRIVATELY MAINTAINED FLOW CONTROL BMPS
Declaration of Covenant for Stormwater Facilities and BMPs is included in Appendix E of this report.
FAMILY FIRST COMMUNITY CENTER
21
X. OPERATION AND MAINTENANCE MANUAL
The Operations and Maintenance manual are provided in Appendix D.
FAMILY FIRST COMMUNITY CENTER
APPENDIX A – FIGURES
FIGURE 1 – TIR WORKSHEET
FIGURE 2 – VICINITY MAP
FIGURE 3 – EXISTING SITE CONDITIONS
FIGURE 4 – PROPOSED SITE CONDITIONS
FIGURE 5 – DRAINAGE BASIN MAP
FIGURE 6 – 100-YR FLOODPLAIN MAP
FIGURE 7 – AQUIFER RECHARGE AREA MAP
FIGURE 8 – OFF-SITE DRAINAGE ANALYSIS MAP
FIGURE 8A –OFF-SITE DRAINAGE TABLE
FIGURE 9 – COAL MINE HAZARD AREA
FIGURE 10 – SOILS MAP
FIGURE 10A – SOILS MAP TABLE
FIGURE 11 – UPSTREAM BASIN DELINEATION MAP
FIGURE 12 – TESC PLAN
City of Renton Family First Community Center
1055 South Grady Way
Aaron Fjelstad
Coughlin Porter Lundeen
206-343-0460
23N
5E
28
16022 116th Ave SE
Renton, WA
Civil Construction Permit
FIGURE 1 - TIR WORKSHEET
C19-006718
Lower Cedar River
Full Drainage Review - City of Renton Surface Water Design Manual
FIGURE 1 - TIR WORKSHEET
(cont'd)
Stormwater adjustment form has been submitted.
Level 2
bioretention
1
1-9
Alderwood gravelly sandy loam 8 to 15%
Arents, Alderwood Material 6 to 15%
The site is considered one Threshold Discharge area, discharging at one
location at southeast corner of site.
9/6/2018
catch basins directly upstream of detention
TBD
FIGURE 1 - TIR WORKSHEET
(cont'd)
Geotechnical Report infiltrative BMPs
FIGURE 1 - TIR WORKSHEET
(cont'd)
Commercial
Aquifer Recharge Area, located > 1 mile away (Fig. 7)
Stormtech Chambers
Modular Wetland Systems
Bioretention
Bioretention
FIGURE 1 - TIR WORKSHEET
(cont'd)
FIGURE 1 - TIR WORKSHEET
(cont'd)
Aaron Fjelstad 4/9/20
FIGURE 2 - VICINITY MAP
Family First Community Center
Baylis Architects
9/4/2018CPS
AJF 1 OF 12014
801 SECOND AVENUE, SUITE 900 SEATTLE, WA 98104 / P 206.343.0460 / cplinc.com
Project
Site
SCALE
1" = 40'
LEGEND
TOTAL
IMPERVIOUS
AREA (AC)
0.52
PERVIOUS
AREA (AC)
2.05
116TH AVE SEEXISTING CASCADE
ELEMENTARY SCHOOL
Family First Community Center
C180040-01 12/03/19 FIGURE 3 - EXISTING CONDITIONS
EXISTING
BIOFILTRATION
SWALE
HIGH POINT
LOW POINT
NATURAL
DISCHARGE POINT
SCALE
1" = 40'
LEGEND
BASIN
EAST
WEST
BYPASS
SUB-TOTAL
WEST
FLOW
THROUGH
TOTAL
IMPERVIOUS
AREA (AC)
0.70
1.38
0
2.08
.11
2.19
PERVIOUS
AREA (AC)
0.14
0.16
0.18
0.49
-
0.49
WEST
BASIN
EAST
BASIN
BASIN BREAK LINE
EXISTING PARKING
LOT TO REMAIN
(MODELED AS
FLOW-THROUGH)
MC-3500 STORMTECH
CHAMBER SYSTEM116TH AVE SEEXISTING CASCADE
ELEMENTARY SCHOOL
BIORETENTION
CELL (772 SF)
FIGURE 4 - PROPOSED CONDITIONS
PGIS AREA TREATED
BY BIORETENTION
CELL = 25,091 SF
SC-310 STORMTECH
CHAMBER SYSTEM
MODULAR WETLAND SYSTEM
MODULAR WETLAND
SYSTEM (TREATING
EXISTING CASCADE ES
PGIS)
PGIS TREATED BY
MODULAR WETLAND
SEE FIGURE 11 FOR
OFFSITE BYPASS AREAS
NATURAL
DISCHARGE
POINT
Project Site
Drainage Basin Boundary
NTS
Project Site 100-YR FLOODPLAIN
NTS
FIGURE 6 - 100-YR FLOODPLAIN MAP
Pictometry, King County, King County
King County iMap - Family First Community Center
Date: 2/4/2020
Notes:±The information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King Countymakes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document isnot intended for use as a survey product. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including,but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map. Any sale of this map or information onthis map is prohibited except by written permission of King County.
Legend
Critical aquifer rechargeareas
category 1
category 2
category 3
FIGURE 7 - AQUIFER RECHARGE AREA MAP
Project
Site
5,222870
City of Renton - Family First Community Center Site
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.
THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere
Notes
None
02/04/2020
Legend
592 0 296 592 Feet
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Floodway
Special Flood Hazard Areas (100 year flood)
Slope City of Renton
>15% & <=25%
>25% & <=40% (Sensitive)
>40% & <=90% (Protected)
>90% (Protected)
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
5' Primary
5' Intermediate
Network Structures
Access Riser
Inlet
Manhole
Utility Vault
Clean Out
Unknown
Pump Stations
Discharge Points
Stormwater Mains
Culverts
Open Drains
Facility Outlines
Private Network Structures
Access Riser
Inlet
Manhole
Clean Out
Utility Vault
Unknown
Private Pump Stations
Private Discharge Points
Private Pipes
Private Culverts
Private Open Drains
Private Facility Outlines
Inactive Pipes
Streets
Parks
Waterbodies
2019.sid
Red: Band_1
Project
Site
Site Discharge
Point
FIGURE 8 - OFF-SITE DRAINAGE MAP
Downstream Flow
Path
1/4 Mile Downstream
0 1 2 3 4
18" Concrete Pipe at
2.4% slope
24" Concrete Pipe at
2.3% slope
15" Concrete Pipe
at approximately
2% slope
24" Concrete Pipe at
4.4% slope
Discharge to
Ginger Creek
9,0281505
City of Renton - Family First Community Center Site
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.
THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere
Notes
None
02/04/2020
Legend
1023 0 512 1023Feet
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Coalmines
High
Moderate
Unclassified
Streets
Parks
Waterbodies
2019.sid
Red: Band_1
Green: Band_2
Blue: Band_3
Extent2010
FIGURE 9 - COAL MINE HAZARD AREA
Project
Site
Soil Map—King County Area, Washington
(Family First Community Center)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/4/2018
Page 1 of 3525625052563005256350525640052564505256500525655052566005256650525625052563005256350525640052564505256500525655052566005256650561340561390561440561490561540561590561640
561340 561390 561440 561490 561540 561590 561640
47° 27' 37'' N 122° 11' 10'' W47° 27' 37'' N122° 10' 55'' W47° 27' 24'' N
122° 11' 10'' W47° 27' 24'' N
122° 10' 55'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84
0 50 100 200 300
Feet
0 30 60 120 180
Meters
Map Scale: 1:2,030 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
Project
Site
FIGURE 10 - SOILS MAP
SEE ATTACHED TABLE
FOR SOIL TYPES
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
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 13, Sep 7, 2017
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 31, 2013—Oct 6,
2013
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.
Soil Map—King County Area, Washington
(Family First Community Center)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/4/2018
Page 2 of 3
FIGURE 4 - SOILS MAP
(CONT)
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
AgC Alderwood gravelly sandy
loam, 8 to 15 percent slopes
0.2 1.1%
AmC Arents, Alderwood material, 6
to 15 percent slopes
16.8 98.9%
Totals for Area of Interest 17.0 100.0%
Soil Map—King County Area, Washington Family First Community Center
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/4/2018
Page 3 of 3
FIGURE 4 - SOILS MAP
(CONT)
4,514752
City of Renton - Family First Community Center Site
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.
THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere
Notes
None
02/03/2020
Legend
512 0 256 512 Feet
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
5' Primary
Streams (Classified)
<all other values>
Type S Shoreline
Type F Fish
Type Np Non-Fish
Type Ns Non-Fish Seasonal
Unclassified
Not Visited
Wetlands
5' Intermediate
Network Structures
Access Riser
Inlet
Manhole
Utility Vault
Clean Out
Unknown
Control Structures
Pump Stations
Discharge Points
Water Quality
Detention Facilities
Pond
Tank
Vault
Bioswale
Wetland
Other
Stormwater Mains
Culverts
Open Drains
Facility Outlines
Private Network Structures
Access Riser
Inlet
Manhole
Clean Out
Utility Vault
Unknown
Private Control Structures
Private Pump Stations
Private Discharge Points
Private Water Quality
Private Detention Facilities
Tank, No
Stormwater Wetland, No; Natural Wetland, No
Filter Strip, No
Infiltration Trench, No
Vault, No
Pond, No; Pond, Unknown
Bioswale, No
Stormtech Chamber, No
Other, No
Private Pipes
Private Culverts
Private Open Drains
UPSTREAM OFF-SITE BASIN = 10.09 ACRES
4.77 ac of impervious Area
5.32 ac of pervious area
(FLOWS THROUGH ON-STE BYPASS -
INCLUDED IN CONVEYANCE CALCS BUT
NOT INLCUDED DETENTION SIZING)
PROJECT SITE
FIGURE 11 - UPSTREAM DELINEATION BASIN MAP
BASIN
HIGH
POINT
A
B
C
E
D
E.2
E.3
F
1110988.2765.554321
F
E
D
C
B
A
1 1.4 2 3 4 5 5.5 6 7 8 8.2 9 10 11
PROTECT EXISTING
CASCADE ELEMENTARY
SCHOOL
PROTECT EXISTING
SIDEWALK
CB PROTECTION (TYP)
WCUT (TYP)
PROTECT EX PARKING
LOT DURING
CONSTRUCTION
INTERCEPTOR SWALE WITH
ROCK CHECK DAMS
SEE DETAILS
SEDIMENT TRAP WITHMOVABLE 55 GALLON
DRUM AND SUMP PUMP
SEE DETAIL
INSTALL SEDIMENT STORAGE TANKS.ONCE EXISTING SWALE CAN NO LONGER
BE USED AS A SEDIMENT TRAP. ROUTE
CONSTRUCTION STORMWATER RUNOFF
TO TANK(S) PRIOR TO DISCHARGE TO EX
STORM SYSTEM
SEE DETAIL
PUMP CLEAN STORMWATERFROM SEDIMENT TANK TO EX
STORM MAIN
REMOVE EX GATESAWCUT (TYP)
SAWCUT (TYP)
SAWCUT
(TYP)
PROTECT EX ELEC'L
POLE AND ASSOCIATED
GUY WIRE
PROTECT EX
LIGHT POLE
PROTECT "NO ACCESS
SIGN"
PROTECT EXAREA DRAIN
PROTECT EX
AREA DRAIN
TECT EX
CAMERA
OTECT EX
-ING" SIGN
116TH AVE SEREMOVE EX
LIGHT POLE
TREE PROTECTIONFENCING SEE DETAIL
PROTECT EX
CATCH BASIN
PROTECT EX WATER
METER VAULT
ECT EX
OL
SIGN
DEMO EX "LOADING
ZONE" SIGN
DEMO EX "LOADING
ZONE" SIGN
REMOVE EX SDMH
CUT AND CAP
EX STORM MAIN
PROTECT EX FIRE HYDRANT PROTECT EX SSMH
PROPOSED
BUILDING
OUTLINE
15
C1.10
19
C1.10
20
C1.10
10
C1.10PROTECT EX
VERT CURB
PROTECT EX
"STOP" SIGN
REMOVE EX
LIGHT POLE
REMOVE EX
"STOP" SIGN
WHEEL WASHSEE DETAIL
CONSTRUCTION
ACCESS GATE
SEE DETAIL
SEDIMENT TRAP WITH
MOVABLE 55 GALLON
DRUM AND SUMP PUMP
SEE DETAIL
REMOVE EX TREES (TYP)9
C1.10
INTERCEPTOR SWALE WITH
ROCK CHECK DAMSSEE DETAILS AND20
C1.10
9
C1.10
EX SWALE AS SEDIMENT
TRAP FOR CONSTRUCTION
RUNOFF DURING
CONSTRUCTION UNTILINSTALLATION OF
STORMTECH CHAMBERS
REMOVE BENCHES AND
SALVAGE TO RENTON
SCHOOL DISTRICT
15
C1.10
5
C1.10 19
C1.10
PROPOSED LOT
LINE PER SHORTPLAN PROCESS
PROPERTY LINE
TREE PROTECTION FENCE BMP C101
REMOVE ASPHALT PAVEMENT
REMOVE CONCRETE PAVEMENT
INLET PROTECTION BMP C220
Legend
LIMITS OF CONSTRUCTION
TEMPORARY CONSTRUCTION FENCING BMP
FILTER FABRIC FENCING BMP C233
INTERCEPTOR SWALE BMP C200
CHECK DAMS BMP C207
REMOVE TREE
REMOVE CURBING
SAWCUT LINE
FIGURE 12 - TESC PLAN
NTS
FAMILY FIRST COMMUNITY CENTER
APPENDIX B – ENGINEERING CALCULATIONS
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.46
Program License Number: 200610002
Project Simulation Performed on: 02/17/2020 6:41 PM
Report Generation Date: 02/17/2020 6:42 PM
—————————————————————————————————
Input File Name: 2020-2-11 Stormtech Sizing.fld
Project Name: Family First Community Center
Analysis Title: Stormtech Chamber Sizing
Comments: 02-11-2020 CPS
Stormtech Sizing for Civil Construction Permit Revisions
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 15
Extended Precipitation Time Series Selected
Climatic Region Number: 15
Full Period of Record Available used for Routing
Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961040 Puget East 40 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) 2.680 2.662
Area of Links that Include Precip/Evap (acres) 0.000 0.018
Total (acres) 2.680 2.680
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Forest 2.570
Impervious 0.110
----------------------------------------------
TOTAL DEVELOPED
AREA PLUS
OFF-SITE FLOW
THROUGH
Subbasin Total 2.680
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 4
---------- Subbasin : West ----------
-------Area (Acres) --------
Till Grass 0.160
Impervious 1.490
----------------------------------------------
Subbasin Total 1.650
---------- Subbasin : East ----------
-------Area (Acres) --------
Till Grass 0.140
Impervious 0.120
----------------------------------------------
Subbasin Total 0.260
---------- Subbasin : Bypass ----------
-------Area (Acres) --------
Till Grass 0.180
----------------------------------------------
Subbasin Total 0.180
---------- Subbasin : East Parking Lot to Biocell ----------
-------Area (Acres) --------
Impervious 0.572
----------------------------------------------
Subbasin Total 0.572
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 1
------------------------------------------
Link Name: New Copy Lnk1
Link Type: Copy
Downstream Link: None
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 4
------------------------------------------
Link Name: MC-3500
Link Type: Structure
Downstream Link Name: New Copy Lnk2
User Specified Elevation Volume Table Used
Elevation (ft) Pond Volume (cu-ft)
450.53 0.
450.62 540.
450.70 809.
450.78 1079.
450.87 1349.
450.95 1619.
451.03 1888.
451.12 2158.
451.20 2428.
451.28 2698.
451.37 2968.
451.45 3237.
451.53 3847.
451.62 4454.
451.70 5059.
451.78 5662.
451.87 6263.
451.95 6862.
452.03 7458.
452.12 8052.
452.20 8643.
452.28 9232.
452.37 9818.
452.45 10401.
452.53 10980.
452.62 11557.
452.70 12130.
452.78 12699.
452.87 13265.
452.95 13826.
453.03 14384.
453.12 14936.
453.20 15485.
453.28 16028.
453.37 16566.
453.45 17098.
453.53 17625.
453.62 18146.
453.70 18660.
453.78 19168.
453.87 19668.
453.95 20161.
454.03 20646.
454.12 21122.
454.20 21589.
454.28 22046.
454.37 22492.
454.45 22927.
454.53 23348.
454.62 23756.
454.70 24146.
454.78 24515.
454.87 24851.
454.95 25160.
455.03 25458.
455.12 25747.
455.20 26022.
455.28 26292.
455.37 26562.
455.45 26831.
455.53 27101.
455.62 27371.
455.70 27641.
455.78 27910.
455.87 28180.
455.95 28450.
456.03 28720.
456.12 28990.
456.20 29259.
Massmann Infiltration Option Used
Hydraulic Conductivity (in/hr) : 0.00
Depth to Water Table (ft) : 100.00
Bio-Fouling Potential : Low
Maintenance : Average or Better
Riser Geometry
Riser Structure Type : Circular
Riser Diameter (in) : 8.00
Common Length (ft) : 0.000
Riser Crest Elevation : 456.20 ft
Hydraulic Structure Geometry
Number of Devices: 2
---Device Number 1 ---
Device Type : Circular Orifice
Control Elevation (ft) : 450.45
Diameter (in) : 0.75
Orientation : Horizontal
Elbow : No
---Device Number 2 ---
Device Type : Circular Orifice
Control Elevation (ft) : 454.85
Diameter (in) : 1.25
Orientation : Horizontal
Elbow : Yes
------------------------------------------
Link Name: New Copy Lnk2
Link Type: Copy
Downstream Link: None
REQUIRED AND
PROVIDED VOLUME
AT OVERFLOW
------------------------------------------
Link Name: SC-310
Link Type: Structure
Downstream Link Name: New Copy Lnk2
User Specified Elevation Volume Table Used
Elevation (ft) Pond Volume (cu-ft)
450.75 0.
450.84 837.
450.92 1255.
451.00 1673.
451.09 2092.
451.17 2510.
451.25 2928.
451.34 3346.
451.42 3765.
451.50 4638.
451.59 5503.
451.67 6354.
451.75 7193.
451.84 8016.
451.92 8820.
452.00 9604.
452.09 10370.
452.17 11111.
452.25 11822.
452.34 12502.
452.42 13144.
452.50 13735.
452.59 14238.
452.67 14705.
452.75 15142.
452.84 15561.
452.92 15979.
453.00 16397.
453.09 16816.
453.17 17234.
453.25 17652.
453.34 18071.
453.42 18489.
453.50 18907.
Massmann Infiltration Option Used
Hydraulic Conductivity (in/hr) : 0.00
Depth to Water Table (ft) : 100.00
Bio-Fouling Potential : Low
Maintenance : Average or Better
Riser Geometry
Riser Structure Type : Circular
Riser Diameter (in) : 8.00
Common Length (ft) : 0.000
Riser Crest Elevation : 453.50 ft
Hydraulic Structure Geometry
REQUIRED AND
PROVIDED VOLUME
AT OVERFLOW
Number of Devices: 2
---Device Number 1 ---
Device Type : Circular Orifice
Control Elevation (ft) : 448.67
Diameter (in) : 0.50
Orientation : Horizontal
Elbow : No
---Device Number 2 ---
Device Type : Circular Orifice
Control Elevation (ft) : 451.99
Diameter (in) : 0.87
Orientation : Horizontal
Elbow : Yes
------------------------------------------
Link Name: Bioretention Cell
Link Type: Bioretention Facility
Downstream Link Name: SC-310
Base Elevation (ft) : 100.00
Riser Crest Elevation (ft) : 100.50
Storage Depth (ft) : 0.50
Bottom Length (ft) : 100.0
Bottom Width (ft) : 7.7
Side Slopes (ft/ft) : L1= 3.00 L2= 3.00 W1= 3.00 W2= 3.00
Bottom Area (sq-ft) : 772.
Area at Riser Crest El (sq-ft) : 1,104.
(acres) : 0.025
Volume at Riser Crest (cu-ft) : 931.
(ac-ft) : 0.021
Infiltration on Bottom and Sideslopes Selected
Soil Properties
Biosoil Thickness (ft) : 1.50
Biosoil Saturated Hydraulic Conductivity (in/hr) : 2.00
Biosoil Porosity (Percent) : 40.00
Maximum Elevation of Bioretention Soil : 101.00
Native Soil Hydraulic Conductivity (in/hr) : 0.00
Underdrain Present
Orifice NOT Present in Under Drain
Riser Geometry
Riser Structure Type : Circular
Riser Diameter (in) : 6.00
Common Length (ft) : 0.000
Riser Crest Elevation : 100.50 ft
Hydraulic Structure Geometry
Number of Devices: 0
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 1
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 4
Number of Links: 4
********** Link: MC-3500 ********** Link Outflow 1
Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 2.303E-02
5-Year 2.706E-02
10-Year 3.058E-02
25-Year 4.466E-02
50-Year 6.086E-02
100-Year 7.429E-02
200-Year 0.107
********** Link: MC-3500 ********** Link WSEL
Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) WSEL Peak (ft)
======================================
1.05-Year 452.026
1.11-Year 452.162
1.25-Year 452.322
2.00-Year 452.804
3.33-Year 453.232
5-Year 453.701
10-Year 454.601
25-Year 454.978
50-Year 455.341
100-Year 455.843
********** Link: SC-310 ********** Link WSEL
Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) WSEL Peak (ft)
======================================
1.05-Year 451.192
1.11-Year 451.316
1.25-Year 451.407
2.00-Year 451.574
3.33-Year 451.712
5-Year 451.851
10-Year 452.119
25-Year 452.252
50-Year 452.388
100-Year 452.557
********** Link: Bioretention Cell ********** Link Outflow 1
Frequency Stats
Flood Frequency Data(cfs)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) Flood Peak (cfs)
======================================
2-Year 0.166
5-Year 0.234
10-Year 0.269
25-Year 0.312
50-Year 0.388
100-Year 0.421
200-Year 0.453
********** Link: Bioretention Cell ********** Link WSEL Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) WSEL Peak (ft)
======================================
1.05-Year 100.506
1.11-Year 100.533
1.25-Year 100.548
2.00-Year 100.577
3.33-Year 100.598
5-Year 100.608
10-Year 100.624
25-Year 100.646
50-Year 100.693
100-Year 100.717
***********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: Subbasin 1 443.142
Link: New Copy Lnk1 0.000
_____________________________________
Total: 443.142
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: West 19.554
Subbasin: East 17.109
Subbasin: Bypass 21.998
Subbasin: East Parking Lot to 0.000
Link: MC-3500 0.000
Link: New Copy Lnk2 0.000
Link: SC-310 Not Computed
Link: Bioretention Cell 0.000
_____________________________________
Total: 58.661
Total Predevelopment Recharge is Greater than Post Developed
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 2.805 ac-ft/year, Post Developed: 0.371 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 1
********** Link: New Copy Lnk1 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 283.23
Inflow Volume Including PPT-Evap (ac-ft): 283.23
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): 283.23
Secondary Outflow To Downstream System (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00%
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 4
********** Link: MC-3500 **********
2-Year Discharge Rate : 0.023 cfs
15-Minute Timestep, Water Quality Treatment Design Discharge
On-line Design Discharge Rate (91% Exceedance): 0.22 cfs
Off-line Design Discharge Rate (91% Exceedance): 0.12 cfs
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 700.22
Inflow Volume Including PPT-Evap (ac-ft): 700.22
Total Runoff Infiltrated (ac-ft): 0.00, 0.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
WATER QUALITY
FLOW RATE USED
FOR SOUTH MWS
SIZING
Primary Outflow To Downstream System (ac-ft): 929.20
Secondary Outflow To Downstream System (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00%
********** Link: New Copy Lnk2 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 2082.20
Inflow Volume Including PPT-Evap (ac-ft): 2082.20
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): 2082.20
Secondary Outflow To Downstream System (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00%
********** Link: Bioretention Cell **********
2-Year Discharge Rate : 0.166 cfs
15-Minute Timestep, Water Quality Treatment Design Discharge
On-line Design Discharge Rate (91% Exceedance): 0.08 cfs
Off-line Design Discharge Rate (91% Exceedance): 0.05 cfs
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 256.46
Inflow Volume Including PPT-Evap (ac-ft): 264.70
Total Runoff Infiltrated (ac-ft): 0.00, 0.00%
Total Runoff Filtered (ac-ft): 258.67, 97.72%
Primary Outflow To Downstream System (ac-ft): 264.95
Secondary Outflow To Downstream System (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered)/Total Volume: 97.72%
***********Compliance Point Results *************
Scenario Predeveloped Compliance Link: New Copy Lnk1
Scenario Postdeveloped Compliance Link: New Copy Lnk2
*** 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 7.862E-02 2-Year 4.502E-02
5-Year 0.124 5-Year 6.132E-02
10-Year 0.162 10-Year 8.363E-02
25-Year 0.202 25-Year 0.101
50-Year 0.251 50-Year 0.111
100-Year 0.282 100-Year 0.126
200-Year 0.404 200-Year 0.150
** Record too Short to Compute Peak Discharge for These Recurrence Intervals
**** Flow Duration Performance ****
PERCENT OF POLLUTANTS
TREATED BY
BIORETENTION CELL
Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): -10.7% PASS
Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): -10.7% PASS
Maximum Excursion from Q2 to Q50 (Must be less than 10%): -78.3% 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%): 768.3% FAIL
Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): 1533.4% FAIL
-------------------------------------------------------------------------------------------------
LID DURATION DESIGN CRITERIA: FAIL
-------------------------------------------------------------------------------------------------
FLOW CONTROL
CRITERIA MET
Project:
Chamber Model - SC-310
Units -Imperial
Number of chambers - 529
Voids in the stone (porosity) - 40 %
Base of Stone Elevation - 450.67 ft
Amount of Stone Above Chambers - 9 in
Amount of Stone Below Chambers - 9 in
6
Height of
System
Incremental Single
Chamber
Incremental
Total Chamber
Incremental
Stone
Incremental Ch
& St
Cumulative
Chamber Elevation
(inches) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (feet)
34 0.00 0.00 418.30 418.30 18907.12 453.50
33 0.00 0.00 418.30 418.30 18488.82 453.42
32 0.00 0.00 418.30 418.30 18070.52 453.34
31 0.00 0.00 418.30 418.30 17652.22 453.25
30 0.00 0.00 418.30 418.30 17233.92 453.17
29 0.00 0.00 418.30 418.30 16815.61 453.09
28 0.00 0.00 418.30 418.30 16397.31 453.00
27 0.00 0.00 418.30 418.30 15979.01 452.92
26 0.00 0.00 418.30 418.30 15560.71 452.84
25 0.06 31.11 405.86 436.97 15142.41 452.75
24 0.15 81.84 385.56 467.41 14705.44 452.67
23 0.27 140.64 362.05 502.69 14238.03 452.59
22 0.54 288.20 303.02 591.22 13735.35 452.50
21 0.70 372.44 269.33 641.77 13144.13 452.42
20 0.82 436.18 243.83 680.01 12502.36 452.34
19 0.92 489.09 222.67 711.76 11822.36 452.25
18 1.01 536.93 203.53 740.46 11110.60 452.17
17 1.09 579.02 186.69 765.71 10370.14 452.09
16 1.15 610.61 174.06 784.67 9604.42 452.00
15 1.21 642.70 161.22 803.92 8819.75 451.92
14 1.27 674.41 148.54 822.95 8015.83 451.84
13 1.32 700.69 138.02 838.72 7192.88 451.75
12 1.36 722.08 129.47 851.55 6354.16 451.67
11 1.40 743.24 121.00 864.25 5502.61 451.59
10 1.43 758.91 114.74 873.65 4638.37 451.50
9 0.00 0.00 418.30 418.30 3764.72 451.42
8 0.00 0.00 418.30 418.30 3346.41 451.34
7 0.00 0.00 418.30 418.30 2928.11 451.25
6 0.00 0.00 418.30 418.30 2509.81 451.17
5 0.00 0.00 418.30 418.30 2091.51 451.09
4 0.00 0.00 418.30 418.30 1673.21 451.00
3 0.00 0.00 418.30 418.30 1254.91 450.92
2 0.00 0.00 418.30 418.30 836.60 450.84
1 0.00 0.00 418.30 418.30 418.30 450.75
StormTech SC-310 Cumulative Storage Volumes
Include Perimeter Stone in Calculations
Click Here for Metric
STAGE STORAGE TABLE USED IN
MGS FLOOD CALCULATIONS FOR
SC-310 SYSTEM
Project:
Chamber Model - MC-3500
Units -Imperial
Number of Chambers -160
Number of End Caps - 10
Voids in the stone (porosity) - 40 %
Base of Stone Elevation - 450.45 ft
Amount of Stone Above Chambers - 12 in
Amount of Stone Below Chambers - 12 in
Amount of Stone Between Chambers - 6 in
Height of
System
Incremental Single
Chamber
Incremental
Single End Cap
Incremental
Chambers
Incremental
End Cap
Incremental
Stone
Incremental Ch,
EC and Stone
Cumulative
System Elevation
(inches) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (cubic feet)(cubic feet) (feet)
69 0.00 0.00 0.00 0.00 269.78 269.78 29259.32 456.20
68 0.00 0.00 0.00 0.00 269.78 269.78 28989.54 456.12
67 0.00 0.00 0.00 0.00 269.78 269.78 28719.77 456.03
66 0.00 0.00 0.00 0.00 269.78 269.78 28449.99 455.95
65 0.00 0.00 0.00 0.00 269.78 269.78 28180.21 455.87
64 0.00 0.00 0.00 0.00 269.78 269.78 27910.43 455.78
63 0.00 0.00 0.00 0.00 269.78 269.78 27640.66 455.70
62 0.00 0.00 0.00 0.00 269.78 269.78 27370.88 455.62
61 0.00 0.00 0.00 0.00 269.78 269.78 27101.10 455.53
60 0.00 0.00 0.00 0.00 269.78 269.78 26831.32 455.45
59 0.00 0.00 0.00 0.00 269.78 269.78 26561.55 455.37
58 0.00 0.00 0.00 0.00 269.78 269.78 26291.77 455.28
57 0.06 0.00 9.29 0.00 266.06 275.35 26021.99 455.20
56 0.19 0.02 31.06 0.24 257.26 288.55 25746.64 455.12
55 0.29 0.04 47.03 0.38 250.81 298.22 25458.08 455.03
54 0.40 0.05 64.58 0.52 243.74 308.84 25159.86 454.95
53 0.69 0.07 109.95 0.68 225.53 336.15 24851.02 454.87
52 1.03 0.09 164.53 0.88 203.61 369.02 24514.87 454.78
51 1.25 0.11 199.92 1.07 189.38 390.38 24145.85 454.70
50 1.42 0.13 227.56 1.26 178.25 407.07 23755.47 454.62
49 1.57 0.14 251.70 1.44 168.52 421.67 23348.40 454.53
48 1.71 0.16 273.14 1.63 159.87 434.64 22926.74 454.45
47 1.83 0.18 292.56 1.82 152.03 446.40 22492.09 454.37
46 1.94 0.20 310.04 2.01 144.96 457.01 22045.69 454.28
45 2.04 0.22 326.53 2.18 138.29 467.01 21588.68 454.20
44 2.13 0.23 341.55 2.35 132.22 476.12 21121.68 454.12
43 2.22 0.25 355.88 2.51 126.43 484.81 20645.56 454.03
42 2.31 0.27 369.09 2.66 121.08 492.82 20160.75 453.95
41 2.38 0.28 381.56 2.80 116.03 500.40 19667.93 453.87
40 2.46 0.29 393.46 2.94 111.22 507.61 19167.54 453.78
39 2.53 0.31 404.51 3.08 106.74 514.33 18659.92 453.70
38 2.59 0.32 415.00 3.21 102.49 520.70 18145.59 453.62
37 2.66 0.33 424.97 3.34 98.45 526.77 17624.89 453.53
36 2.72 0.35 434.42 3.47 94.62 532.51 17098.12 453.45
35 2.77 0.36 443.41 3.60 90.98 537.98 16565.61 453.37
34 2.82 0.37 451.94 3.72 87.51 543.18 16027.63 453.28
33 2.88 0.38 460.07 3.84 84.21 548.13 15484.45 453.20
32 2.92 0.40 467.86 3.96 81.05 552.87 14936.33 453.12
31 2.97 0.41 475.18 4.08 78.07 557.33 14383.45 453.03
30 3.01 0.42 481.99 4.19 75.31 561.49 13826.12 452.95
29 3.05 0.43 488.52 4.30 72.65 565.47 13264.64 452.87
28 3.09 0.44 495.08 4.40 69.98 569.47 12699.17 452.78
27 3.13 0.45 500.89 4.51 67.62 573.02 12129.70 452.70
26 3.17 0.46 506.51 4.61 65.33 576.45 11556.68 452.62
25 3.20 0.47 511.91 4.71 63.13 579.75 10980.24 452.53
24 3.23 0.48 516.98 4.80 61.07 582.85 10400.49 452.45
23 3.26 0.49 521.83 4.89 59.09 585.81 9817.64 452.37
22 3.29 0.50 526.44 4.98 57.21 588.63 9231.83 452.28
21 3.32 0.51 530.87 5.06 55.40 591.34 8643.20 452.20
20 3.34 0.51 535.06 5.14 53.70 593.90 8051.86 452.12
19 3.37 0.52 538.98 5.22 52.10 596.30 7457.96 452.03
18 3.39 0.53 542.80 5.30 50.54 598.64 6861.66 451.95
17 3.41 0.54 546.33 5.37 49.10 600.79 6263.03 451.87
16 3.44 0.54 549.92 5.43 47.64 602.99 5662.24 451.78
15 3.46 0.55 553.23 5.49 46.29 605.01 5059.25 451.70
14 3.48 0.56 556.59 5.55 44.92 607.06 4454.23 451.62
13 3.51 0.59 560.81 5.95 43.07 609.84 3847.17 451.53
12 0.00 0.00 0.00 0.00 269.78 269.78 3237.33 451.45
11 0.00 0.00 0.00 0.00 269.78 269.78 2967.55 451.37
10 0.00 0.00 0.00 0.00 269.78 269.78 2697.78 451.28
9 0.00 0.00 0.00 0.00 269.78 269.78 2428.00 451.20
8 0.00 0.00 0.00 0.00 269.78 269.78 2158.22 451.12
7 0.00 0.00 0.00 0.00 269.78 269.78 1888.44 451.03
6 0.00 0.00 0.00 0.00 269.78 269.78 1618.67 450.95
5 0.00 0.00 0.00 0.00 269.78 269.78 1348.89 450.87
4 0.00 0.00 0.00 0.00 269.78 269.78 1079.11 450.78
StormTech MC-3500 Cumulative Storage Volumes
Include Perimeter Stone in Calculations
Click Here for Metric STAGE STORAGE
TABLE USED IN MGS
FLOOD
CALCULATIONS FOR
MC-3500 SYSTEM
DESIGN REQUEST – MODULAR WETLAND SYSTEM - LINEAR
Fill out the information below. This will assist us in providing you with detailed sizing, drawings & pricing.
1. Project Name: _________________________________________________________
2. Project State & City: ___________________________________________________
3. Unit ID (if several units are on same project): ______________________________________
4. Your Name: __________________________________________________________
5. Your Contact Email/Phone #: / ___________________________________________
6. Desired Date to Receive Sizing/Drawings/Pricing: ___________________________
7. Configuration: Standard (open vegetated planter-depth limited) Underground (no plants-full concrete top)
NOTE: Some regulators will only accept units with vegetated open planters to meet their definition of biofiltration.
8. Loading Requirements: Parkway Indirect Traffic Direct Traffic Other
8a. If Other Please List Details (i.e. HS25): ________________________________________
NOTE: Standard units have parkway rated manholes and/or hatches. Underground configurations can have traffic rated manholes/hatches by
request. All will be bolt & pull style. Hinged hatches are available per request but will add cost. Standard units require irrigation and must be
placed in a landscape area.
9. Runoff Entry Method: Piped Flow Built-In Curb Inlet Built-In Grate Inlet
NOTE: Units may have only piped flow or a combination of piped flow and a grate or curb inlet. Units may be able to accept
multiple inflow pipes. Size of pipe is limited based upon the size of the unit.
10. Water Quality Flow Rate: ___________CFS (standalone offline or online flow rate) OR
10a. 2-Year Release Rate: _____________CFS (downstream of detention release rate) OR
10b. Drainage Area (acres) & Impervious Coefficient: ___________________________
NOTE: Units may be sized for either the water quality flow or water quality volume. For water quality volume a pre-detention is required.
For areas of the country where flow based design is desired but local regulations do not offer a method to calculate water quality flow please
provide the drainage area (acres) and the impervious coefficient. Our engineering team will determine the necessary size required based upon
local rainfall patterns to treat 90% of storm events.
11. Internal Bypass Desired: Yes No
11b. Peak Flow Rate (if internal bypass desired): _____________CFS (Dependent on local regulations)
NOTE: Side-by-side orientation units have the option of internal bypass. End-to-end units do not have an internal bypass option. Internal
bypass needs to be used with caution and a hydraulic assessment is required for each unit including running the HGL calculations over the
bypass weir during peak flow and comparing this to FS elevations of the units and all upstream catch basins. For a standard height unit (4.13
ft) the water level must build to 3.4 ft above invert of outflow pipe to treat listed flow capacity on sizing sheet. Shallower and deeper units are
available. Weir can be set lower to accommodate higher bypass flows and lower the associated HGL but will reduce flow capacity of the unit.
Please contact manufacturer for calculations and assistance. Other external bypass configurations available such as an external diversions
structure, secondary catch basin, or DVERT trough.
12. Finish Grade Elevation (FS, TC, TG): _______________________________________
13. Inlet Pipe Invert Elevation (if applicable): ___________________________________
13a. Inlet Pipe Diameter/Type (i.e. 8” / PVC): ____________________________________
14. Outlet Pipe Invert Elevation: ____________________________________________
14a. Outlet Pipe Diameter/Type (i.e. 12” / RCP): _________________________________
NOTE: For flow based design at least 16” of fall required between invert in and invert out. For volume based design at
least 6” of fall required between invert in and invert out for hydraulically connected pre-detention.
15. Ground Water Elevation (if applicable): _____________________________________
16. Corrosive Soil Conditions (if applicable): ____________________________________
Please email to us: info@modularwetlands.com
Any questions, contact: (866) 566-3938
DOES IT NEED BUY AMERICA CERTIFICATION?
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.46
Program License Number: 200610002
Project Simulation Performed on: 03/31/2020 12:46 PM
Report Generation Date: 03/31/2020 12:47 PM
—————————————————————————————————
Input File Name: 2020-03-31 North MWS Sizing Upstream.fld
Project Name: Family First Community Center
Analysis Title: Civil Permit MWS Sizing
Comments: 3-31-20 CPS
MWS Sizing Civil Construction Permit
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 15
Extended Precipitation Time Series Selected
Climatic Region Number: 15
Full Period of Record Available used for Routing
Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961040 Puget East 40 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) 2.420 2.420
Area of Links that Include Precip/Evap (acres) 0.000 0.000
Total (acres) 2.420 2.420
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Forest 2.420
----------------------------------------------
Subbasin Total 2.420
MGSFLOOD REPORT FOR DESIGNING UPSTREAM BYPASS NORTH MWS
AND DETERMINING WATER QUALITY DESIGN FLOW RATE
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Upstream ----------
-------Area (Acres) --------
Till Grass 0.500
Impervious 1.920
----------------------------------------------
Subbasin Total 2.420
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 1
------------------------------------------
Link Name: New Copy Lnk1
Link Type: Copy
Downstream Link: None
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
------------------------------------------
Link Name: New Copy Lnk2
Link Type: Copy
Downstream Link: None
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 1
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
Number of Links: 1
***********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: Subbasin 1 417.278
Link: New Copy Lnk1 0.000
_____________________________________
Total: 417.278
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Upstream 61.105
Link: New Copy Lnk2 0.000
_____________________________________
Total: 61.105
Total Predevelopment Recharge is Greater than Post Developed
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 2.641 ac-ft/year, Post Developed: 0.387 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 1
********** Link: New Copy Lnk1 **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 220.26
Inflow Volume Including PPT-Evap (ac-ft): 220.26
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): 220.26
Secondary Outflow To Downstream System (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00%
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
********** Link: New Copy Lnk2 **********
2-Year Discharge Rate : 0.761 cfs
15-Minute Timestep, Water Quality Treatment Design Discharge
On-line Design Discharge Rate (91% Exceedance): 0.28 cfs
Off-line Design Discharge Rate (91% Exceedance): 0.15 cfs
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 961.38
Inflow Volume Including PPT-Evap (ac-ft): 961.38
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): 961.38
Secondary Outflow To Downstream System (ac-ft): 0.00
OFF-LINE DESIGN
DISCHARGE RATE FOR
UPSTREAM BYPASS
NORTH MWS SYSTEM.
SUBJECT TO
CORRECTION FACTOR
(K) PER 2017 CRSWDM.
SEE SECTION 4 PART
E FOR CALCULATION
Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00%
***********Compliance Point Results *************
Scenario Predeveloped Compliance Link: New Copy Lnk1
Scenario Postdeveloped Compliance Link: New Copy Lnk2
*** 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 5.157E-02 2-Year 0.761
5-Year 8.405E-02 5-Year 0.975
10-Year 0.113 10-Year 1.155
25-Year 0.144 25-Year 1.533
50-Year 0.183 50-Year 1.797
100-Year 0.199 100-Year 2.227
200-Year 0.309 200-Year 2.270
** 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%): 614.0% FAIL
Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): 2721.9% FAIL
Maximum Excursion from Q2 to Q50 (Must be less than 10%): 99999.0% FAIL
Percent Excursion from Q2 to Q50 (Must be less than 50%): 100.0% FAIL
-------------------------------------------------------------------------------------------------
FLOW DURATION DESIGN CRITERIA: FAIL
-------------------------------------------------------------------------------------------------
**** LID Duration Performance ****
Excursion at Predeveloped 8%Q2 (Must be Less Than 0%): 68.8% FAIL
Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): 614.0% FAIL
-------------------------------------------------------------------------------------------------
LID DURATION DESIGN CRITERIA: FAIL
-------------------------------------------------------------------------------------------------
2-YR DISCHARGE
RATE FOR NORTH
MWS
DESIGN REQUEST – MODULAR WETLAND SYSTEM - LINEAR
Fill out the information below. This will assist us in providing you with detailed sizing, drawings & pricing.
1. Project Name: _________________________________________________________
2. Project State & City: ___________________________________________________
3. Unit ID (if several units are on same project): ______________________________________
4. Your Name: __________________________________________________________
5. Your Contact Email/Phone #: / ___________________________________________
6. Desired Date to Receive Sizing/Drawings/Pricing: ___________________________
7. Configuration: Standard (open vegetated planter-depth limited) Underground (no plants-full concrete top)
NOTE: Some regulators will only accept units with vegetated open planters to meet their definition of biofiltration.
8. Loading Requirements: Parkway Indirect Traffic Direct Traffic Other
8a. If Other Please List Details (i.e. HS25): ________________________________________
NOTE: Standard units have parkway rated manholes and/or hatches. Underground configurations can have traffic rated manholes/hatches by
request. All will be bolt & pull style. Hinged hatches are available per request but will add cost. Standard units require irrigation and must be
placed in a landscape area.
9. Runoff Entry Method: Piped Flow Built-In Curb Inlet Built-In Grate Inlet
NOTE: Units may have only piped flow or a combination of piped flow and a grate or curb inlet. Units may be able to accept
multiple inflow pipes. Size of pipe is limited based upon the size of the unit.
10. Water Quality Flow Rate: ___________CFS (standalone offline or online flow rate) OR
10a. 2-Year Release Rate: _____________CFS (downstream of detention release rate) OR
10b. Drainage Area (acres) & Impervious Coefficient: ___________________________
NOTE: Units may be sized for either the water quality flow or water quality volume. For water quality volume a pre-detention is required.
For areas of the country where flow based design is desired but local regulations do not offer a method to calculate water quality flow please
provide the drainage area (acres) and the impervious coefficient. Our engineering team will determine the necessary size required based upon
local rainfall patterns to treat 90% of storm events.
11. Internal Bypass Desired: Yes No
11b. Peak Flow Rate (if internal bypass desired): _____________CFS (Dependent on local regulations)
NOTE: Side-by-side orientation units have the option of internal bypass. End-to-end units do not have an internal bypass option. Internal
bypass needs to be used with caution and a hydraulic assessment is required for each unit including running the HGL calculations over the
bypass weir during peak flow and comparing this to FS elevations of the units and all upstream catch basins. For a standard height unit (4.13
ft) the water level must build to 3.4 ft above invert of outflow pipe to treat listed flow capacity on sizing sheet. Shallower and deeper units are
available. Weir can be set lower to accommodate higher bypass flows and lower the associated HGL but will reduce flow capacity of the unit.
Please contact manufacturer for calculations and assistance. Other external bypass configurations available such as an external diversions
structure, secondary catch basin, or DVERT trough.
12. Finish Grade Elevation (FS, TC, TG): _______________________________________
13. Inlet Pipe Invert Elevation (if applicable): ___________________________________
13a. Inlet Pipe Diameter/Type (i.e. 8” / PVC): ____________________________________
14. Outlet Pipe Invert Elevation: ____________________________________________
14a. Outlet Pipe Diameter/Type (i.e. 12” / RCP): _________________________________
NOTE: For flow based design at least 16” of fall required between invert in and invert out. For volume based design at
least 6” of fall required between invert in and invert out for hydraulically connected pre-detention.
15. Ground Water Elevation (if applicable): _____________________________________
16. Corrosive Soil Conditions (if applicable): ____________________________________
Please email to us: info@modularwetlands.com
Any questions, contact: (866) 566-3938
DOES IT NEED BUY AMERICA CERTIFICATION?
DESIGN REQUEST FOR MODULAR WETLAND DOWNSTREAM OF MC-3500
CHAMBER SYSTEM
CONVEYANCE AREAS
SCALE
50 ft
UPSTREAM
STORM SYSTEM
3,114.1 sf
253.7 sf
3,609.4 sf
6,655.6 sf
329.6 sf
5,530.7 sf
2,144.9 sf
425.2 sf
210.4 sf
746.2 sf
5,531 sf
514.5 sf
372.7 sf
7,484.6 sf
86.3 sf190.6 sf
204.7 sf
500.8 sf
6,622.8 sf78 sf
181.9 sf
385.2 sf
241.6 sf
24.8 sf
26,217.1 sf
1,717.8 sf
139.4 sf
653.1 sf230.7 sf
1,434.4 sf
574.4 sf
7,049.2 sf
5,247.3 sf
6,302.1 sf
1,314 sf
905.8 sf
865.7 sf
1,081.5 sf
1,299.7 sf
4,560 sf
201.2 sf
193.1 sf
Time of Concentration
is set to a minimum
6.3 minutes for all
runs (unless
otherwise noted).
Setting the Link
Routing to
"Hydrodynamic"
allows a backwater
analysis to be
performed. See below
for more information.
Excerpt from Storm and Sanitary
Analysis 2016 User's Guide:
SSA SETTINGS
IDF CURVE CALCULATIONS
SSA IDF Curve Input:
B = (PR)(aR) = (3.4)(2.66) = 9.044 (P25 = 3.4 per the King County Surface Water Design Manual,
a25 = 2.66 for the 25-Year, 24-Hour Storm)
E = bR = 0.65 (b25 = 0.65 for the 25-Year, 24-Hour Storm. *Note that the (-) negative sign is
dropped because the exponent has been brought to the denominator in the SSA equation. )
Tc+D = Tc = 6.3 + 0 (*Note that the time of concentration in SSA is set to 6.3 minutes. The "D"
variable is used to show a variance in the time of concentration, which in this case is zero.)
SSA uses the "i" value calculated in this equation to plug into the rational method (Q=CiA) to
calculate the flow for each structure on the site.
For the 100-year 24-hour storm, P100 = 3.9, a100 = 2.61, b100 = 0.63, and D=0.
Rational Calculation: IR = (PR)(aR)(Tc)-br
SSA Equation: i = B /(Tc+D)^E
25-YEAR, 24-HR PIPE ANALYSIS RESULTS
25-YEAR, 24-HOUR OUTFALL ANALYSIS RESULTS
Fixed boundaries represent a
downstream condition where
the downstream pipe is
assumed to be completely full.
Outfall into detention system
is modeled as a storage node
with the water surface set to
the max water surface
elevation.
25-YEAR, 24-HOUR STRUCTURE ANALYSIS RESULTS
25-YEAR, 24-HOUR SUBBASIN ANALYSIS RESULTS
SSA PROFILE LAYOUT
SCALE
50 ft
A
B
C
E
D
E.2
E.3
F
1110988.2765.554321
F
E
D
C
B
A
1 1.4 2 3 4 5 5.5 6 7 88.2 9 10 11
2.0%PROFILE 1
PROFILE 2
PROFILE 3
PROFILE 4
PROFILE 5
PROFILE 6
PROFILE 7
PROFILE 8
PROFILE 9
25-YEAR, 24-HOUR STORM PROFILE 1
Maximum
water elevation
in structure
Hydraulic
Grade Line
(HGL)
Connection
to EX Storm
System
Rim - Max HGL
= Min Freeboard
attained
Structure name
25-YEAR, 24-HOUR STORM PROFILE 2
25-YEAR, 24-HOUR STORM PROFILE 3
25-YEAR, 24-HOUR STORM PROFILE 4
25-YEAR, 24-HOUR STORM PROFILE 5
25-YEAR, 24-HOUR STORM PROFILE 6
25-YEAR, 24-HOUR STORM PROFILE 7
25-YEAR, 24-HOUR STORM PROFILE 8
25-YEAR, 24-HOUR STORM PROFILE 9
100-YEAR, 24-HR PIPE ANALYSIS RESULTS
100-YEAR, 24-HOUR OUTFALL ANALYSIS RESULTS
100-YEAR, 24-HOUR STRUCTURE ANALYSIS RESULTS
100-YEAR, 24-HOUR SUBBASIN ANALYSIS RESULTS
100-YEAR, 24-HOUR STORM PROFILE 1
100-YEAR, 24-HOUR STORM PROFILE 2
100-YEAR, 24-HOUR STORM PROFILE 3
100-YEAR, 24-HOUR STORM PROFILE 4
100-YEAR, 24-HOUR STORM PROFILE 5
100-YEAR, 24-HOUR STORM PROFILE 6
100-YEAR, 24-HOUR STORM PROFILE 7
100-YEAR, 24-HOUR STORM PROFILE 8
100-YEAR, 24-HOUR STORM PROFILE 9
PROJECT SITE
Pr = 3.4
FIGURE 41 - 25-yr, 24-hr Isopluvial Map
PROJECT SITE
Pr = 3.9
FIGURE 42 - 100-yr, 24-hr Isopluvial Map
FAMILY FIRST COMMUNITY CENTER
APPENDIX C – CSWPPP
Construction Stormwater General Permit
Stormwater Pollution Prevention Plan
(SWPPP)
for
Family First Community Center
Prepared for:
The Washington State Department of Ecology
Northwest Regional Office
3190 160th Ave. SE
Bellevue, WA 98008
Permittee / Owner Developer Operator / Contractor
Renton School District City of Renton TBD
Project Site Location: 16022 116th Ave SE, Renton WA
Certified Erosion and Sediment Control Lead (CESCL)
Name Organization Contact Phone Number
TBD TBD TBD
SWPPP Prepared By
Name Organization Contact Phone Number
Aaron Fjelstad Coughlin Porter Lundeen 206-343-0460
SWPPP Preparation Date
12-03-2019
Project Construction Dates
Activity / Phase Start Date End Date
Clearing and Grading TBD TBD
Foundation and Slab TBD TBD
Final Completion TBD TBD
P a g e | 1
Table of Contents
1 Project Information .............................................................................................................. 4
1.1 Existing Conditions ...................................................................................................... 4
1.2 Proposed Construction Activities .................................................................................. 4
2 Construction Stormwater Best Management Practices (BMPs) ........................................... 6
2.1 The 13 Elements .......................................................................................................... 6
2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits ........................................ 6
2.1.2 Element 2: Establish Construction Access ............................................................ 7
2.1.3 Element 3: Control Flow Rates ............................................................................. 8
2.1.4 Element 4: Install Sediment Controls .................................................................... 9
2.1.5 Element 5: Stabilize Soils ....................................................................................10
2.1.6 Element 6: Protect Slopes....................................................................................11
2.1.7 Element 7: Protect Drain Inlets ............................................................................12
2.1.8 Element 8: Stabilize Channels and Outlets ..........................................................13
2.1.9 Element 9: Control Pollutants ...............................................................................14
2.1.10 Element 10: Control Dewatering ..........................................................................18
2.1.11 Element 11: Maintain BMPs .................................................................................19
2.1.12 Element 12: Manage the Project ..........................................................................20
2.1.13 Element 13: Protect Low Impact Development (LID) BMPs .................................23
3 Pollution Prevention Team .................................................................................................24
4 Monitoring and Sampling Requirements ............................................................................25
4.1 Site Inspection ............................................................................................................25
4.2 Stormwater Quality Sampling ......................................................................................25
4.2.1 Turbidity Sampling ...............................................................................................25
4.2.2 pH Sampling ........................................................................................................27
5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies .........................28
5.1 303(d) Listed Waterbodies ..........................................................................................28
5.2 TMDL Waterbodies .....................................................................................................28
6 Reporting and Record Keeping ..........................................................................................29
6.1 Record Keeping ..........................................................................................................29
6.1.1 Site Log Book ......................................................................................................29
6.1.2 Records Retention ...............................................................................................29
6.1.3 Updating the SWPPP ...........................................................................................29
6.2 Reporting ....................................................................................................................30
6.2.1 Discharge Monitoring Reports ..............................................................................30
6.2.2 Notification of Noncompliance ..............................................................................30
P a g e | 2
List of Tables
Table 1 – Summary of Site Pollutant Constituents ..................................................................... 4
Table 2 – Pollutants ..................................................................................................................14
Table 3 – pH-Modifying Sources ...............................................................................................16
Table 4 – Dewatering BMPs ......................................................................................................18
Table 5 – Management .............................................................................................................20
Table 6 – BMP Implementation Schedule .................................................................................21
Table 7 – Team Information ......................................................................................................24
Table 8 – Turbidity Sampling Method ........................................................................................25
Table 9 – pH Sampling Method .................................................................................................27
List of Appendices
Appendix/Glossary
A. Site Map
B. BMP Detail
C. Correspondence
D. Site Inspection Form
E. Construction Stormwater General Permit (CSWGP)
F. 303(d) List Waterbodies / TMDL Waterbodies Information
G. Contaminated Site Information
H. Engineering Calculations
P a g e | 3
List of Acronyms and Abbreviations
Acronym / Abbreviation Explanation
303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies
BFO Bellingham Field Office of the Department of Ecology
BMP(s) Best Management Practice(s)
CESCL Certified Erosion and Sediment Control Lead
CO2 Carbon Dioxide
CRO Central Regional Office of the Department of Ecology
CSWGP Construction Stormwater General Permit
CWA Clean Water Act
DMR Discharge Monitoring Report
DO Dissolved Oxygen
Ecology Washington State Department of Ecology
EPA United States Environmental Protection Agency
ERO Eastern Regional Office of the Department of Ecology
ERTS Environmental Report Tracking System
ESC Erosion and Sediment Control
GULD General Use Level Designation
NPDES National Pollutant Discharge Elimination System
NTU Nephelometric Turbidity Units
NWRO Northwest Regional Office of the Department of Ecology
pH Power of Hydrogen
RCW Revised Code of Washington
SPCC Spill Prevention, Control, and Countermeasure
su Standard Units
SWMMEW Stormwater Management Manual for Eastern Washington
SWMMWW Stormwater Management Manual for Western Washington
SWPPP Stormwater Pollution Prevention Plan
TESC Temporary Erosion and Sediment Control
SWRO Southwest Regional Office of the Department of Ecology
TMDL Total Maximum Daily Load
VFO Vancouver Field Office of the Department of Ecology
WAC Washington Administrative Code
WSDOT Washington Department of Transportation
WWHM Western Washington Hydrology Model
P a g e | 4
1 Project Information
Project/Site Name: Family First Community Center
Street/Location: 16022 116th Avenue SE
City: Renton State: WA Zip code: 98058
Subdivision:
Receiving waterbody: Lower Cedar River
1.1 Existing Conditions
Total acreage (including support activities such as off-site equipment staging yards, material
storage areas, borrow areas).
Total acreage (total
parcel area):
14.9
Disturbed acreage: 2.51
Existing structures: 0
Landscape topography: 1.61
Drainage patterns: The site drains through a residential area to the east of the site
before reaching 119th Avenue SE, where the road slopes down
towards a catch basin before being conveyed further east.
Existing Vegetation: Approximately 1.6 acres of undisturbed forest and landscape
areas, with 0.9 acres of existing impervious surfaces.
Critical Areas (wetlands, streams,
high erosion risk, steep or difficult to
stabilize slopes):
There are no Critical Areas mapped
down or upstream of the project site.
List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the
receiving waterbody: The site discharges to the Cedar River, which is a 303(d) listed water
body. The Cedar River is listed for temperature, dissolved oxygen, ammonia, pH, bacteria,
arsenic, mercury, selenium, and copper impairments.
1.2 Proposed Construction Activities
Description of site development (example: subdivision):
The site development will consist of a new one-story community recreational center with an
asphalt parking lot. It will include a new gymnasium, activity rooms, gathering places, offices, a
kitchen, and associated landscaping and sidewalks
Description of construction activities (example: site preparation, demolition, excavation):
Construction activities will include site preparation, demolition, excavation, grading, poured
concrete sidewalks, asphalt paving and construction of the new recreational center.
Description of site drainage including flow from and onto adjacent properties. Must be consistent
with Site Map in Appendix A:
P a g e | 5
The project will remove the existing water quality treatment facility for the Cascade Elementary
school and replace the facility with a Modular Wetland System to treat the pollution-generating
runoff from the existing site. Runoff will then be re-routed to the existing storm system located at
the southeast corner of the site before reaching the system within 119th Ave SE.
Description of final stabilization (example: extent of revegetation, paving, landscaping):
Natural vegetation will be kept to the maximum extent feasible, the rest of the site will be
developed with paving or landscaping.
Contaminated Site Information:
Proposed activities regarding contaminated soils or groundwater (example: on-site treatment
system, authorized sanitary sewer discharge):
There are no contaminated soils or groundwater on this site.
P a g e | 6
2 Construction Stormwater Best Management Practices (BMPs)
The SWPPP is a living document reflecting current conditions and changes throughout the life
of the project. These changes may be informal (i.e., hand-written notes and deletions). Update
the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design.
2.1 The 13 Elements
2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits
To protect adjacent properties and to reduce the area of soil exposed to construction, the limits
of construction will be clearly marked before land-disturbing activities begin. Trees that are to
be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in
the field and on the plans. In general, natural vegetation and native topsoil shall be retained in
an undisturbed state to the maximum extent possible.
List and describe BMPs:
Preserving Natural Vegetation (Tree Protection Fence) (BMP C101)
High Visibility Plastic or Metal Fence (BMP C103)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 7
2.1.2 Element 2: Establish Construction Access
Construction access or activities occurring on unpaved areas shall be minimized, yet where
necessary, access points shall be stabilized to minimize the tracking of sediment onto public
roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent
sediment from entering state waters. All wash wastewater shall be controlled on site. All site
ingress/egress stabilization BMPs shall be installed according to BMP C105. Sediment will be
removed from paved areas in and adjacent to construction work areas manually or using
mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from
the site and to minimize washoff of sediments from adjacent streets in runoff.
List and describe BMPs:
High Visibility Fence (Construction Fencing) (BMP C103)
Stabilized Construction Entrance (BMP C105)
Wheel Wash (BMP C106)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 8
2.1.3 Element 3: Control Flow Rates
In order to protect the properties and waterways downstream of the project site, stormwater
discharges from the site will be controlled. This project will utilize two Stormtech Chamber
detention systems to direct construction runoff to a sediment trap, where it will be pumped to a
baker tank. Baker tanks will be used for on site stormwater and discharged to the existing storm
system via the proposed onsite conveyance system.
Will you construct stormwater retention and/or detention facilities?
Yes No
Will you use permanent infiltration ponds or other low impact development (example: rain
gardens, bio-retention, porous pavement) to control flow during construction?
Yes No
List and describe BMPs:
Check Dams (BMP C207)
Sediment Trap (BMP C240)
Temporary Sediment Pond (BMP C241)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 9
2.1.4 Element 4: Install Sediment Controls
All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal
BMP before leaving the construction site or prior to being discharged to an infiltration facility. A
temporary sediment pond will be provided on site, and clean storm water will be discharged to
the existing storm system after settling. Immediate action will be taken at the first sign of BMPs
that are ineffective or failing.
List and describe BMPs:
• Silt Fence (BMP C233)
• Interceptor Swale (BMP C200)
• Sediment Trap (BMP C240)
• Storm Drain Inlet Protection (BMP C220)
• Materials on Hand (BMP C150) may also be applicable
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 10
2.1.5 Element 5: Stabilize Soils
Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent
erosion throughout the life of the project.
West of the Cascade Mountains Crest
Season Dates Number of Days Soils Can
be Left Exposed
During the Dry Season May 1 – September 30 7 days
During the Wet Season October 1 – April 30 2 days
Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on
the weather forecast.
Anticipated project dates: Start date: April 2020 End date: March 2021
Will you construct during the wet season?
Yes No
List and describe BMPs:
• Temporary and Permanent Seeding (BMP C120)
• Mulching (BMP C121)
• Nets and Blankets (BMP C122)
• Plastic Covering (BMP C123)
• Surface Roughening (BMP C130)
• Dust Control (BMP C140)
• Early application of gravel base on areas to be paved
• Materials on Hand (BMP C150) may also be applicable.
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 11
2.1.6 Element 6: Protect Slopes
All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes
erosion.
Will steep slopes be present at the site during construction?
Yes No
List and describe BMPs:
• Temporary and Permanent Seeding (BMP C120)
• Surface Roughening (BMP C130)
• Interceptor Swale (BMP C200)
• Level Spreader (BMP C206)
• Check Dams (BMP C207)
• Materials on Hand (BMP C150)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 12
2.1.7 Element 7: Protect Drain Inlets
All storm drain inlets and culverts made operable during construction shall be protected to
prevent unfiltered or untreated water from entering the drainage conveyance system. However,
the first priority is to keep all access roads clean of sediment and keep street wash water
separate from entering storm drains until treatment can be provided. Storm Drain Inlet
Protection (BMP C220) will be implemented for all drainage inlets and culverts that could
potentially be impacted by sediment-laden runoff on and near the project site.
List and describe BMPs:
• Storm Drain Inlet Protection (BMP C220)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 13
2.1.8 Element 8: Stabilize Channels and Outlets
Where site runoff is to be conveyed in channels, or discharged to a stream or some other
natural drainage point, efforts will be taken to prevent downstream erosion.
Provide stabilization, including armoring material, adequate to prevent erosion of outlets,
adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all
conveyance systems.
List and describe BMPs:
Outlet Protection (BMP C209)
Check Dams (BMP C207)
Interceptor Swale (BMP C200)
Materials on Hand (BMP C150)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 14
2.1.9 Element 9: Control Pollutants
The following pollutants are anticipated to be present on-site:
Table 2 – Pollutants
Pollutant (List pollutants and source, if applicable)
Vehicles and construction equipment
Demolition
Concrete and grout
All pollutants, including waste materials and demolition debris, that occur onsite shall be
handled and disposed of in a manner that does not cause contamination of stormwater. Good
housekeeping and preventative measures will be taken to ensure that the site will be kept clean,
well organized, and free of debris.
Vehicles, construction equipment, and/or petroleum product storage/dispensing:
• All vehicles, equipment, and petroleum product storage/dispensing areas will be
inspected regularly to detect any leaks or spills, and to identify maintenance needs to
prevent leaks or spills.
• On-site fueling tanks and petroleum product storage containers shall include
secondary containment.
• Spill prevention measures, such as drip pans, will be used when conducting
maintenance and repair of vehicles or equipment.
• In order to perform emergency repairs on site, temporary plastic will be placed
beneath and, if raining, over the vehicle.
• Contaminated surfaces shall be cleaned immediately following any discharge or spill
incident.
Demolition:
• Dust released from demolished sidewalks, buildings, or structures will be controlled
using Dust Control measures (BMP C140).
• Storm drain inlets vulnerable to stormwater discharge carrying dust, soil, or debris
will be protected using Storm Drain Inlet Protection (BMP C220 as described above
for Element 7).
• Process water and slurry resulting from sawcutting and surfacing operations will be
prevented from entering the waters of the State by implementing Sawcutting and
Surfacing Pollution Prevention measures (BMP C152).
Concrete and grout:
• Process water and slurry resulting from concrete work will be prevented from
entering the waters of the State by implementing Concrete Handling measures (BMP
C151).
P a g e | 15
Sanitary wastewater:
• Portable sanitation facilities will be firmly secured, regularly maintained, and emptied
when necessary.
• Wheel wash or tire bath wastewater shall be discharged to a separate on-site
treatment system or to the sanitary sewer as part of Wheel Wash implementation
(BMP C106).
List and describe BMPs:
• Dust Control (BMP C140)
• Storm Drain Inlet Protection (BMP C220)
• Sawcutting and Surfacing Pollution Prevention (BMP C152)
• Concrete Handling (BMP C151)
• Wheel Wash (BMP C106)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site?
Yes No
List and describe BMPs: N/A
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
Will wheel wash or tire bath system BMPs be used during construction?
Yes No
Water discharged from the wheel wash will be routed to the baker tank on site, which will allow
sediment to settle before the water is sent to a level spreader on site.
List and describe BMPs:
• Wheel Wash (BMP C106)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e | 16
Will pH-modifying sources be present on-site?
Yes No
Table 3 – pH-Modifying Sources
None
Bulk cement
Cement kiln dust
Fly ash
Other cementitious materials
New concrete washing or curing waters
Waste streams generated from concrete grinding and sawing
Exposed aggregate processes
Dewatering concrete vaults
Concrete pumping and mixer washout waters
Recycled concrete
Recycled concrete stockpiles
Other (i.e., calcium lignosulfate) [please describe: ]
List and describe BMPs:
• Sawcutting and Surfacing Pollution Prevention (BMP C152)
• Concrete Handling (BMP C151)
• Wheel Wash (BMP C106)
Installation Schedules: TBD
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches,
streets, or streams. Excess concrete must not be dumped on-site, except in designated
concrete washout areas with appropriate BMPs installed.
Will uncontaminated water from water-only based shaft drilling for construction of building, road,
and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits
discharge to surface waters?
Yes No
List and describe BMPs: N/A
Installation Schedules: N/A
P a g e | 17
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
P a g e | 18
2.1.10 Element 10: Control Dewatering
This project site does not propose dewatering and therefore will not be implementing any BMPs
associated with Element 10.
Table 4 – Dewatering BMPs
Infiltration
Transport off-site in a vehicle (vacuum truck for legal disposal)
Ecology-approved on-site chemical treatment or other suitable treatment technologies
Sanitary or combined sewer discharge with local sewer district approval (last resort)
Use of sedimentation bag with discharge to ditch or swale (small volumes of localized
dewatering)
List and describe BMPs: N/A
Installation Schedules: N/A
Inspection and Maintenance plan: N/A
Responsible Staff: N/A
P a g e | 19
2.1.11 Element 11: Maintain BMPs
All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained
and repaired as needed to ensure continued performance of their intended function.
Maintenance and repair shall be conducted in accordance with each particular BMP
specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW).
Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar
week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the
site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to
once every calendar month.
All temporary ESC BMPs shall be removed within 30 days after final site stabilization is
achieved or after the temporary BMPs are no longer needed.
Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal
of either BMPs or vegetation shall be permanently stabilized.
The Grading Permit will be utilized as required to repair the private road for the extension of
utilities.
Additionally, protection must be provided for all BMPs installed for the permanent control of
stormwater from sediment and compaction. BMPs that are to remain in place following
completion of construction shall be examined and restored to full operating condition. If
sediment enters these BMPs during construction, the sediment shall be removed and the facility
shall be returned to conditions specified in the construction documents.
P a g e | 20
2.1.12 Element 12: Manage the Project
The project will be managed based on the following principles:
Projects will be phased to the maximum extent practicable and seasonal work limitations
will be taken into account.
Inspection and monitoring:
o Inspection, maintenance and repair of all BMPs will occur as needed to ensure
performance of their intended function.
o Site inspections and monitoring will be conducted in accordance with Special
Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map.
Sampling station(s) are located in accordance with applicable requirements of
the CSWGP.
Maintain an updated SWPPP.
o The SWPPP will be updated, maintained, and implemented in accordance with
Special Conditions S3, S4, and S9 of the CSWGP.
As site work progresses the SWPPP will be modified routinely to reflect changing site
conditions. The SWPPP will be reviewed monthly to ensure the content is current.
Table 5 – Management
Design the project to fit the existing topography, soils, and drainage patterns
Emphasize erosion control rather than sediment control
Minimize the extent and duration of the area exposed
Keep runoff velocities low
Retain sediment on-site
Thoroughly monitor site and maintain all ESC measures
Schedule major earthwork during the dry season
Other (please describe)
P a g e | 21
Table 6 – BMP Implementation Schedule
Phase of Construction
Project
Stormwater BMPs Date Wet/Dry
Season
[Insert construction
activity]
[Insert BMP] [MM/DD/YYYY] [Insert
Season]
Phase of Construction
Project
Stormwater BMPs Date Wet/Dry
Season
P a g e | 22
[Insert construction
activity]
[Insert BMP] [MM/DD/YYYY] [Insert
Season]
P a g e | 23
2.1.13 Element 13: Protect Low Impact Development (LID) BMPs
Bioretention is proposed for this project. Areas where bioretention is to be installed will be
protected during construction.
P a g e | 24
3 Pollution Prevention Team
Table 7 – Team Information
Title Name(s) Phone Number
Certified Erosion and
Sediment Control Lead
(CESCL)
TBD TBD
Resident Engineer TBD TBD
Emergency Ecology
Contact
TBD TBD
Emergency Permittee/
Owner Contact
TBD TBD
Non-Emergency Owner
Contact
TBD TBD
Monitoring Personnel TBD TBD
Ecology Regional Office Northwest Regional Office 425-649-7098
P a g e | 25
4 Monitoring and Sampling Requirements
Monitoring includes visual inspection, sampling for water quality parameters of concern, and
documentation of the inspection and sampling findings in a site log book. A site log book will be
maintained for all on-site construction activities and will include:
A record of the implementation of the SWPPP and other permit requirements
Site inspections
Stormwater sampling data
File a blank form under Appendix D.
The site log book must be maintained on-site within reasonable access to the site and be made
available upon request to Ecology or the local jurisdiction.
Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See
CSWGP Special Condition S8 and Section 5 of this template.
4.1 Site Inspection
Site inspections will be conducted at least once every calendar week and within 24 hours
following any discharge from the site. For sites that are temporarily stabilized and inactive, the
required frequency is reduced to once per calendar month.
The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with
the applicable requirements of the CSWGP.
4.2 Stormwater Quality Sampling
4.2.1 Turbidity Sampling
Requirements include calibrated turbidity meter or transparency tube to sample site discharges
for compliance with the CSWGP. Sampling will be conducted at all discharge points at least
once per calendar week.
Method for sampling turbidity:
Table 8 – Turbidity Sampling Method
Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size)
Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size)
The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency
less than 33 centimeters.
If the discharge’s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to
or greater than 6 cm, the following steps will be conducted:
1. Review the SWPPP for compliance with Special Condition S9. Make appropriate
revisions within 7 days of the date the discharge exceeded the benchmark.
P a g e | 26
2. Immediately begin the process to fully implement and maintain appropriate source
control and/or treatment BMPs as soon as possible. Address the problems within 10
days of the date the discharge exceeded the benchmark. If installation of necessary
treatment BMPs is not feasible within 10 days, Ecology may approve additional time
when the Permittee requests an extension within the initial 10-day response period.
3. Document BMP implementation and maintenance in the site log book.
If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following
steps will be conducted:
1. Telephone or submit an electronic report to the applicable Ecology Region’s
Environmental Report Tracking System (ERTS) within 24 hours.
Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan,
Yakima): (509) 575-2490 or
http://www.ecy.wa.gov/programs/spills/forms/nerts_online/CRO_nerts_online.html
Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant,
Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400
or http://www.ecy.wa.gov/programs/spills/forms/nerts_online/ERO_nerts_online.html
Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish,
Whatcom): (425) 649-7000 or
http://www.ecy.wa.gov/programs/spills/forms/nerts_online/NWRO_nerts_online.html
Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis,
Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 or
http://www.ecy.wa.gov/programs/spills/forms/nerts_online/SWRO_nerts_online.html
2. Immediately begin the process to fully implement and maintain appropriate source
control and/or treatment BMPs as soon as possible. Address the problems within 10
days of the date the discharge exceeded the benchmark. If installation of necessary
treatment BMPs is not feasible within 10 days, Ecology may approve additional time
when the Permittee requests an extension within the initial 10-day response period
3. Document BMP implementation and maintenance in the site log book.
4. Continue to sample discharges daily until one of the following is true:
Turbidity is 25 NTU (or lower).
Transparency is 33 cm (or greater).
Compliance with the water quality limit for turbidity is achieved.
o 1 - 5 NTU over background turbidity, if background is less than 50 NTU
o 1% - 10% over background turbidity, if background is 50 NTU or greater
The discharge stops or is eliminated.
P a g e | 27
4.2.2 pH Sampling
pH monitoring is required for “Significant concrete work” (i.e., greater than 1000 cubic yards
poured concrete over the life of the project). The use of recycled concrete or engineered soils
(soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln
dust [CKD] or fly ash) also requires pH monitoring.
For significant concrete work, pH sampling will start the first day concrete is poured and
continue until it is cured, typically three (3) weeks after the last pour.
For engineered soils and recycled concrete, pH sampling begins when engineered soils or
recycled concrete are first exposed to precipitation and continues until the area is fully
stabilized.
If the measured pH is 8.5 or greater, the following measures will be taken:
1. Prevent high pH water from entering storm sewer systems or surface water.
2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate
technology such as carbon dioxide (CO2) sparging (liquid or dry ice).
3. Written approval will be obtained from Ecology prior to the use of chemical treatment
other than CO2 sparging or dry ice.
Method for sampling pH:
Table 9 – pH Sampling Method
pH meter
pH test kit
Wide range pH indicator paper
P a g e | 28
5 Discharges to 303(d) or Total Maximum Daily Load (TMDL)
Waterbodies
5.1 303(d) Listed Waterbodies
Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH?
Yes No
5.2 TMDL Waterbodies
Waste Load Allocation for CWSGP discharges:
The site drains through a residential area to the east of the site before reaching 119th Avenue
SE, where the road slopes down towards a catch basin before being conveyed further east. The
project will remove the existing water quality treatment facility for the Cascade Elementary
school and replace the facility with a Modular Wetland System to treat the pollution-generating
runoff from the existing site. Runoff will then be re-routed to the existing storm system located at
the southeast corner of the site before reaching the system within 119th Ave SE.
List and describe BMPs:
N/A
Discharges to TMDL receiving waterbodies will meet in-stream water quality criteria at the point
of discharge.
The Construction Stormwater General Permit Proposed New Discharge to an Impaired Water
Body form is included in Appendix F.
P a g e | 29
6 Reporting and Record Keeping
6.1 Record Keeping
6.1.1 Site Log Book
A site log book will be maintained for all on-site construction activities and will include:
A record of the implementation of the SWPPP and other permit requirements
Site inspections
Sample logs
6.1.2 Records Retention
Records will be retained during the life of the project and for a minimum of three (3) years
following the termination of permit coverage in accordance with Special Condition S5.C of the
CSWGP.
Permit documentation to be retained on-site:
CSWGP
Permit Coverage Letter
SWPPP
Site Log Book
Permit documentation will be provided within 14 days of receipt of a written request from
Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when
requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP.
6.1.3 Updating the SWPPP
The SWPPP will be modified if:
Found ineffective in eliminating or significantly minimizing pollutants in stormwater
discharges from the site.
There is a change in design, construction, operation, or maintenance at the construction
site that has, or could have, a significant effect on the discharge of pollutants to waters
of the State.
The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine
additional or modified BMPs are necessary for compliance. An updated timeline for BMP
implementation will be prepared.
P a g e | 30
6.2 Reporting
6.2.1 Discharge Monitoring Reports
Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring
Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given
monitoring period the DMR will be submitted as required, reporting “No Discharge”. The DMR
due date is fifteen (15) days following the end of each calendar month.
DMRs will be reported online through Ecology’s WQWebDMR System.
6.2.2 Notification of Noncompliance
If any of the terms and conditions of the permit is not met, and the resulting noncompliance may
cause a threat to human health or the environment, the following actions will be taken:
1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable
Regional office ERTS phone number (Regional office numbers listed below).
2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or
correct the noncompliance. If applicable, sampling and analysis of any noncompliance
will be repeated immediately and the results submitted to Ecology within five (5) days of
becoming aware of the violation.
3. A detailed written report describing the noncompliance will be submitted to Ecology
within five (5) days, unless requested earlier by Ecology.
Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6
cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as
required by Special Condition S5.A of the CSWGP.
Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit,
Snohomish, or Whatcom County
Include the following information:
1. Your name and / Phone number
2. Permit number
3. City / County of project
4. Sample results
5. Date / Time of call
6. Date / Time of sample
7. Project name
In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will
be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH
water.
P a g e | 31
Appendix/Glossary
A. Site Map
B. BMP Detail
C. Correspondence
N/A
D. Site Inspection Form
E. Construction Stormwater General Permit (CSWGP)
F. 303(d) List Waterbodies / TMDL Waterbodies Information
N/A
G. Contaminated Site Information
N/A
H. Engineering Calculations
P a g e | 32
Appendix A – Site Map
Family First Community Center
C180040-01 Baylis Architects
12/4/19CPS
AJF 1 OF 1
FIGURE 1 - VICINITY MAP2014
801 SECOND AVENUE, SUITE 900 SEATTLE, WA 98104 / P 206.343.0460 / cplinc.com
Project
Site
SCALE
1" = 40'
Legend
Description Quantity Unit
Existing Landscape to Remain 31,085.60 sf
NPGIS 36,657.40 sf
PGIS 59,327.72 sf
Proposed Pervious 22,202.14 sf
FIGURE 2 - PROPOSED CONDITIONSFamily First Community Center
C180040-01 12/03/19
P a g e | 33
Appendix B – BMP Details
BMP C101: Preserving Natural Vegetation
Purpose
The purpose of preserving natural vegetation is to reduce erosion wherever practicable. Limiting
site disturbance is the single most effective method for reducing erosion. For example, conifers
can hold up to about 50 percent of all rain that falls during a storm. Up to 20-30 percent of this
rain may never reach the ground but is taken up by the tree or evaporates. Another benefit is
that the rain held in the tree can be released slowly to the ground after the storm.
Conditions of Use
Natural vegetation should be preserved on steep slopes, near perennial and intermittent
watercourses or swales, and on building sites in wooded areas.
As required by local governments.
Phase construction to preserve natural vegetation on the project site for as long as
possible during the construction period.
Design and Installation Specifications
Natural vegetation can be preserved in natural clumps or as individual trees, shrubs and vines.
The preservation of individual plants is more difficult because heavy equipment is generally
used to remove unwanted vegetation. The points to remember when attempting to save
individual plants are:
Is the plant worth saving? Consider the location, species, size, age, vigor, and the work
involved. Local governments may also have ordinances to save natural vegetation and
trees.
Fence or clearly mark areas around trees that are to be saved. It is preferable to keep
ground disturbance away from the trees at least as far out as the dripline.
Plants need protection from three kinds of injuries:
Construction Equipment - This injury can be above or below the ground level. Damage
results from scarring, cutting of roots, and compaction of the soil. Placing a fenced buffer
zone around plants to be saved prior to construction can prevent construction equipment
injuries.
Grade Changes - Changing the natural ground level will alter grades, which affects the
plant's ability to obtain the necessary air, water, and minerals. Minor fills usually do not
cause problems although sensitivity between species does vary and should be checked.
Trees can typically tolerate fill of 6 inches or less. For shrubs and other plants, the fill
should be less.
When there are major changes in grade, it may become necessary to supply air to the
roots of plants. This can be done by placing a layer of gravel and a tile system over the
roots before the fill is made. A tile system protects a tree from a raised grade. The tile
system should be laid out on the original grade leading from a dry well around the tree
trunk. The system should then be covered with small stones to allow air to circulate over
the root area.
Lowering the natural ground level can seriously damage trees and shrubs. The highest
percentage of the plant roots are in the upper 12 inches of the soil and cuts of only 2-3
inches can cause serious injury. To protect the roots it may be necessary to terrace the
immediate area around the plants to be saved. If roots are exposed, construction of
retaining walls may be needed to keep the soil in place. Plants can also be preserved by
leaving them on an undisturbed, gently sloping mound. To increase the chances for
survival, it is best to limit grade changes and other soil disturbances to areas outside the
dripline of the plant.
Excavations - Protect trees and other plants when excavating for drainfields, power,
water, and sewer lines. Where possible, the trenches should be routed around trees and
large shrubs. When this is not possible, it is best to tunnel under them. This can be done
with hand tools or with power augers. If it is not possible to route the trench around
plants to be saved, then the following should be observed:
o Cut as few roots as possible. When you have to cut, cut clean. Paint cut root
ends with a wood dressing like asphalt base paint if roots will be exposed for
more than 24-hours.
o Backfill the trench as soon as possible.
o Tunnel beneath root systems as close to the center of the main trunk to preserve
most of the important feeder roots.
Some problems that can be encountered with a few specific trees are:
Maple, Dogwood, Red alder, Western hemlock, Western red cedar, and Douglas fir do
not readily adjust to changes in environment and special care should be taken to protect
these trees.
The windthrow hazard of Pacific silver fir and madrona is high, while that of Western
hemlock is moderate. The danger of windthrow increases where dense stands have
been thinned. Other species (unless they are on shallow, wet soils less than 20 inches
deep) have a low windthrow hazard.
Cottonwoods, maples, and willows have water-seeking roots. These can cause trouble
in sewer lines and infiltration fields. On the other hand, they thrive in high moisture
conditions that other trees would not.
Thinning operations in pure or mixed stands of Grand fir, Pacific silver fir, Noble fir, Sitka
spruce, Western red cedar, Western hemlock, Pacific dogwood, and Red alder can
cause serious disease problems. Disease can become established through damaged
limbs, trunks, roots, and freshly cut stumps. Diseased and weakened trees are also
susceptible to insect attack.
Maintenance Standards
Inspect flagged and/or fenced areas regularly to make sure flagging or fencing has not been
removed or damaged. If the flagging or fencing has been damaged or visibility reduced, it shall
be repaired or replaced immediately and visibility restored.
If tree roots have been exposed or injured, “prune” cleanly with an appropriate pruning
saw or loppers directly above the damaged roots and recover with native soils.
Treatment of sap flowing trees (fir, hemlock, pine, soft maples) is not advised as sap
forms a natural healing barrier.
BMP C103: High Visibility Fence
Purpose
Fencing is intended to:
1. Restrict clearing to approved limits.
2. Prevent disturbance of sensitive areas, their buffers, and other areas required to be left
undisturbed.
3. Limit construction traffic to designated construction entrances, exits, or internal roads.
4. Protect areas where marking with survey tape may not provide adequate protection.
Conditions of Use
To establish clearing limits plastic, fabric, or metal fence may be used:
At the boundary of sensitive areas, their buffers, and other areas required to be left
uncleared.
As necessary to control vehicle access to and on the site.
Design and Installation Specifications
High visibility plastic fence shall be composed of a high-density polyethylene material and shall
be at least four feet in height. Posts for the fencing shall be steel or wood and placed every 6
feet on center (maximum) or as needed to ensure rigidity. The fencing shall be fastened to the
post every six inches with a polyethylene tie. On long continuous lengths of fencing, a tension
wire or rope shall be used as a top stringer to prevent sagging between posts. The fence color
shall be high visibility orange. The fence tensile strength shall be 360 lbs./ft. using the ASTM
D4595 testing method.
If appropriate install fabric silt fence in accordance with BMP C233: Silt Fence to act as high
visibility fence. Silt fence shall be at least 3 feet high and must be highly visible to meet the
requirements of this BMP.
Metal fences shall be designed and installed according to the manufacturer's specifications.
Metal fences shall be at least 3 feet high and must be highly visible.
Fences shall not be wired or stapled to trees.
Maintenance Standards
If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately
and visibility restored.
BMP C105: Stabilized Construction Entrance /
Exit
Purpose
Stabilized Construction entrances are established to reduce the amount of sediment transported
onto paved roads by vehicles or equipment. This is done by constructing a stabilized pad of
quarry spalls at entrances and exits for construction sites.
Conditions of Use
Construction entrances shall be stabilized wherever traffic will be entering or leaving a
construction site if paved roads or other paved areas are within 1,000 feet of the site.
For residential construction provide stabilized construction entrances for each residence, rather
than only at the main subdivision entrance. Stabilized surfaces shall be of sufficient length/width
to provide vehicle access/parking, based on lot size/configuration.
On large commercial, highway, and road projects, the designer should include enough extra
materials in the contract to allow for additional stabilized entrances not shown in the initial
Construction SWPPP. It is difficult to determine exactly where access to these projects will take
place; additional materials will enable the contractor to install them where needed.
Design and Installation Specifications
See Figure II-4.1.1 Stabilized Construction Entrance for details. Note: the 100’ minimum length
of the entrance shall be reduced to the maximum practicable size when the size or configuration
of the site does not allow the full length (100’).
Construct stabilized construction entrances with a 12-inch thick pad of 4-inch to 8-inch quarry
spalls, a 4-inch course of asphalt treated base (ATB), or use existing pavement. Do not use
crushed concrete, cement, or calcium chloride for construction entrance stabilization because
these products raise pH levels in stormwater and concrete discharge to surface waters of the
State is prohibited.
A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping
up into the rock pad. The geotextile shall meet the following standards:
Grab Tensile Strength (ASTM D4751) 200 psi min.
Grab Tensile Elongation (ASTM D4632) 30% max.
Mullen Burst Strength (ASTM D3786-80a) 400 psi min.
AOS (ASTM D4751) 20-45 (U.S. standard sieve size)
Consider early installation of the first lift of asphalt in areas that will paved; this can be
used as a stabilized entrance. Also consider the installation of excess concrete as a
stabilized entrance. During large concrete pours, excess concrete is often available for
this purpose.
Fencing (see BMP C103: High Visibility Fence) shall be installed as necessary to restrict
traffic to the construction entrance.
Whenever possible, the entrance shall be constructed on a firm, compacted subgrade.
This can substantially increase the effectiveness of the pad and reduce the need for
maintenance.
Construction entrances should avoid crossing existing sidewalks and back of walk drains
if at all possible. If a construction entrance must cross a sidewalk or back of walk drain,
the full length of the sidewalk and back of walk drain must be covered and protected
from sediment leaving the site.
Maintenance Standards
Quarry spalls shall be added if the pad is no longer in accordance with the specifications.
If the entrance is not preventing sediment from being tracked onto pavement, then
alternative measures to keep the streets free of sediment shall be used. This may
include replacement/cleaning of the existing quarry spalls, street sweeping, an increase
in the dimensions of the entrance, or the installation of a wheel wash.
Any sediment that is tracked onto pavement shall be removed by shoveling or street
sweeping. The sediment collected by sweeping shall be removed or stabilized on site.
The pavement shall not be cleaned by washing down the street, except when high
efficiency sweeping is ineffective and there is a threat to public safety. If it is necessary
to wash the streets, the construction of a small sump to contain the wash water shall be
considered. The sediment would then be washed into the sump where it can be
controlled.
Perform street sweeping by hand or with a high efficiency sweeper. Do not use a non-
high efficiency mechanical sweeper because this creates dust and throws soils into
storm systems or conveyance ditches.
Any quarry spalls that are loosened from the pad, which end up on the roadway shall be
removed immediately.
If vehicles are entering or exiting the site at points other than the construction
entrance(s), fencing (see BMP C103) shall be installed to control traffic.
Upon project completion and site stabilization, all construction accesses intended as
permanent access for maintenance shall be permanently stabilized.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C105:
Stabilized Construction Entrance / Exit. The products did not pass through the
Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions may
choose not to accept this product approved as equivalent, or may require additional
testing prior to consideration for local use. The products are available for review on
Ecology’s website
at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html
DEPAR TM E N T OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.1.1
Stabilized Construction Entrance
Revised June 2015
NOT TO SCALE
Existing
R
o
a
d
Notes:
1.Driveway shall meet
the requirements of the
permitting agency.
2.It is recommended that
the entrance be
crowned so that runoff
drains off the pad.
Install driveway
culvert if there is a
roadside ditch present 4" - 8" quarry
spalls
Geotextile
12" minimum thickness
15' min.
100' min.
Provide full width
of ingress/egress
area
BMP C106: Wheel Wash
Purpose
Wheel washes reduce the amount of sediment transported onto paved roads by motor vehicles.
Conditions of Use
When a stabilized construction entrance (see BMP C105: Stabilized Construction Entrance /
Exit) is not preventing sediment from being tracked onto pavement.
Wheel washing is generally an effective BMP when installed with careful attention to
topography. For example, a wheel wash can be detrimental if installed at the top of a
slope abutting a right-of-way where the water from the dripping truck can run unimpeded
into the street.
Pressure washing combined with an adequately sized and surfaced pad with direct
drainage to a large 10-foot x 10-foot sump can be very effective.
Discharge wheel wash or tire bath wastewater to a separate on-site treatment system
that prevents discharge to surface water, such as closed-loop recirculation or upland
land application, or to the sanitary sewer with local sewer district approval.
Wheel wash or tire bath wastewater should not include wastewater from concrete
washout areas.
Design and Installation Specifications
Suggested details are shown in Figure II-4.1.2 Wheel Wash. The Local Permitting Authority may
allow other designs. A minimum of 6 inches of asphalt treated base (ATB) over crushed base
material or 8 inches over a good subgrade is recommended to pave the wheel wash.
Use a low clearance truck to test the wheel wash before paving. Either a belly dump or lowboy
will work well to test clearance.
Keep the water level from 12 to 14 inches deep to avoid damage to truck hubs and filling the
truck tongues with water.
Midpoint spray nozzles are only needed in extremely muddy conditions.
Wheel wash systems should be designed with a small grade change, 6- to 12-inches for a 10-
foot-wide pond, to allow sediment to flow to the low side of pond to help prevent re-suspension
of sediment. A drainpipe with a 2- to 3-foot riser should be installed on the low side of the pond
to allow for easy cleaning and refilling. Polymers may be used to promote coagulation and
flocculation in a closed-loop system. Polyacrylamide (PAM) added to the wheel wash water at a
rate of 0.25 - 0.5 pounds per 1,000 gallons of water increases effectiveness and reduces
cleanup time. If PAM is already being used for dust or erosion control and is being applied by a
water truck, the same truck can be used to change the wash water.
Maintenance Standards
The wheel wash should start out the day with fresh water.
The wash water should be changed a minimum of once per day. On large earthwork jobs where
more than 10-20 trucks per hour are expected, the wash water will need to be changed more
often.
DEPAR TM E N T OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.1.2
Wheel Wash
Revised June 2015
NOT TO SCALE
Notes:
1.Build 8' x 8' sump to accomodate
cleaning by trackhoe.
6" sewer pipe with
butterfly valves
8' x 8' sump with 5' of catch
3" trash pump with
floats on suction hose
2" schedule 40
1 12 " schedule 40 for sprayers
midpoint spray nozzles, if needed
15' ATB apron to protect
ground from splashing water
6" sleeve under road
6" ATB construction entrance
Asphalt curb on the low road
side to direct water back to pond
Ball valves
2% slope 5:1 slope
1:1 slope
5:1 slope 2% slope
A
A
Plan View
15'15'20'15'50'
Curb
6" sleeve
Elevation View
Locate invert of top pipe 1'
above bottom of wheel wash
8' x 8' sump
5'
Drain pipe
12'
3'
18'
Water level
1:1 slope
Section A-A
BMP C120: Temporary and Permanent Seeding
Purpose
Seeding reduces erosion by stabilizing exposed soils. A well-established vegetative cover is one
of the most effective methods of reducing erosion.
Conditions of Use
Use seeding throughout the project on disturbed areas that have reached final grade or that will
remain unworked for more than 30 days.
The optimum seeding windows for western Washington are April 1 through June 30 and
September 1 through October 1.
Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is
established.
Between October 1 and March 30 seeding requires a cover of mulch with straw or an erosion
control blanket until 75 percent grass cover is established.
Review all disturbed areas in late August to early September and complete all seeding by the
end of September. Otherwise, vegetation will not establish itself enough to provide more than
average protection.
Mulch is required at all times for seeding because it protects seeds from heat, moisture
loss, and transport due to runoff. Mulch can be applied on top of the seed or
simultaneously by hydroseeding. See BMP C121: Mulching for specifications.
Seed and mulch, all disturbed areas not otherwise vegetated at final site stabilization.
Final stabilization means the completion of all soil disturbing activities at the site and the
establishment of a permanent vegetative cover, or equivalent permanent stabilization
measures (such as pavement, riprap, gabions, or geotextiles) which will prevent erosion.
Design and Installation Specifications
Seed retention/detention ponds as required.
Install channels intended for vegetation before starting major earthwork and hydroseed with a
Bonded Fiber Matrix. For vegetated channels that will have high flows, install erosion control
blankets over hydroseed. Before allowing water to flow in vegetated channels, establish 75
percent vegetation cover. If vegetated channels cannot be established by seed before water
flow; install sod in the channel bottom—over hydromulch and erosion control blankets.
Confirm the installation of all required surface water control measures to prevent seed
from washing away.
Hydroseed applications shall include a minimum of 1,500 pounds per acre of mulch with
3 percent tackifier. See BMP C121: Mulching for specifications.
Areas that will have seeding only and not landscaping may need compost or meal-based
mulch included in the hydroseed in order to establish vegetation. Re-install native topsoil
on the disturbed soil surface before application.
When installing seed via hydroseeding operations, only about 1/3 of the seed actually
ends up in contact with the soil surface. This reduces the ability to establish a good
stand of grass quickly. To overcome this, consider increasing seed quantities by up to 50
percent.
Enhance vegetation establishment by dividing the hydromulch operation into two
phases:
1. Phase 1- Install all seed and fertilizer with 25-30 percent mulch and tackifier onto
soil in the first lift.
2. Phase 2- Install the rest of the mulch and tackifier over the first lift.
Or, enhance vegetation by:
1. Installing the mulch, seed, fertilizer, and tackifier in one lift.
2. Spread or blow straw over the top of the hydromulch at a rate of 800-1000 pounds
per acre.
3. Hold straw in place with a standard tackifier.
Both of these approaches will increase cost moderately but will greatly improve and
enhance vegetative establishment. The increased cost may be offset by the reduced
need for:
o Irrigation.
o Reapplication of mulch.
o Repair of failed slope surfaces.
This technique works with standard hydromulch (1,500 pounds per acre minimum) and
BFM/MBFMs (3,000 pounds per acre minimum).
Seed may be installed by hand if:
o Temporary and covered by straw, mulch, or topsoil.
o Permanent in small areas (usually less than 1 acre) and covered with mulch,
topsoil, or erosion blankets.
o The seed mixes listed in the tables below include recommended mixes for both
temporary and permanent seeding.
o Apply these mixes, with the exception of the wetland mix, at a rate of 120 pounds
per acre. This rate can be reduced if soil amendments or slow-release fertilizers
are used.
o Consult the local suppliers or the local conservation district for their
recommendations because the appropriate mix depends on a variety of factors,
including location, exposure, soil type, slope, and expected foot traffic.
Alternative seed mixes approved by the local authority may be used.
o Other mixes may be appropriate, depending on the soil type and hydrology of the
area.
Table II-4.1.2 Temporary Erosion Control Seed Mix lists the standard mix for areas
requiring a temporary vegetative cover.
Table II-4.1.2 Temporary Erosion Control Seed Mix
% Weight % Purity % Germination
Chewings or annual blue grass
Festuca rubra var. commutata or Poa anna
40 98 90
Perennial rye
Lolium perenne
50 98 90
Redtop or colonial bentgrass
Agrostis alba or Agrostis tenuis
5 92 85
White dutch clover
Trifolium repens
5 98 90
Table II-4.1.3 Landscaping Seed Mix lists a recommended mix for landscaping seed.
Table II-4.1.3 Landscaping Seed Mix
% Weight % Purity % Germination
Perennial rye blend 70 98 90
Table II-4.1.3 Landscaping Seed Mix
% Weight % Purity % Germination
Lolium perenne
Chewings and red fescue blend
Festuca rubra var. commutata or Festuca rubra
30 98 90
Table II-4.1.4 Low-Growing Turf Seed Mix lists a turf seed mix for dry situations where
there is no need for watering. This mix requires very little maintenance.
Table II-4.1.4 Low-Growing Turf Seed Mix
% Weight % Purity % Germination
Dwarf tall fescue (several varieties)
Festuca arundinacea var.
45 98 90
Dwarf perennial rye (Barclay)
Lolium perenne var. barclay
30 98 90
Red fescue
Festuca rubra
20 98 90
Colonial bentgrass
Agrostis tenuis
5 98 90
Table II-4.1.5 Bioswale Seed Mix* lists a mix for bioswales and other intermittently wet
areas.
Table II-4.1.5 Bioswale Seed Mix*
% Weight % Purity % Germination
Tall or meadow fescue
Festuca arundinacea or Festuca elatior
75-80 98 90
Table II-4.1.5 Bioswale Seed Mix*
% Weight % Purity % Germination
Seaside/Creeping bentgrass
Agrostis palustris
10-15 92 85
Redtop bentgrass
Agrostis alba or Agrostis gigantea
5-10 90 80
* Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix
Table II-4.1.6 Wet Area Seed Mix* lists a low-growing, relatively non-invasive seed mix
appropriate for very wet areas that are not regulated wetlands. Apply this mixture at a
rate of 60 pounds per acre. Consult Hydraulic Permit Authority (HPA) for seed mixes if
applicable.
Table II-4.1.6 Wet Area Seed Mix*
% Weight % Purity % Germination
Tall or meadow fescue
Festuca arundinacea or Festuca elatior
60-70 98 90
Seaside/Creeping bentgrass
Agrostis palustris
10-15 98 85
Meadow foxtail
Alepocurus pratensis
10-15 90 80
Alsike clover
Trifolium hybridum
1-6 98 90
Redtop bentgrass
Agrostis alba
1-6 92 85
* Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix
Table II-4.1.7 Meadow Seed Mix lists a recommended meadow seed mix for infrequently
maintained areas or non-maintained areas where colonization by native plants is
desirable. Likely applications include rural road and utility right-of-way. Seeding should
take place in September or very early October in order to obtain adequate establishment
prior to the winter months. Consider the appropriateness of clover, a fairly invasive
species, in the mix. Amending the soil can reduce the need for clover.
Table II-4.1.7 Meadow Seed Mix
% Weight % Purity % Germination
Redtop or Oregon bentgrass
Agrostis alba or Agrostis oregonensis
20 92 85
Red fescue
Festuca rubra
70 98 90
White dutch clover
Trifolium repens
10 98 90
Roughening and Rototilling:
o The seedbed should be firm and rough. Roughen all soil no matter what the
slope. Track walk slopes before seeding if engineering purposes require
compaction. Backblading or smoothing of slopes greater than 4H:1V is not
allowed if they are to be seeded.
o Restoration-based landscape practices require deeper incorporation than that
provided by a simple single-pass rototilling treatment. Wherever practical, initially
rip the subgrade to improve long-term permeability, infiltration, and water inflow
qualities. At a minimum, permanent areas shall use soil amendments to achieve
organic matter and permeability performance defined in engineered
soil/landscape systems. For systems that are deeper than 8 inches complete the
rototilling process in multiple lifts, or prepare the engineered soil system per
specifications and place to achieve the specified depth.
Fertilizers:
o Conducting soil tests to determine the exact type and quantity of fertilizer is
recommended. This will prevent the over-application of fertilizer.
o Organic matter is the most appropriate form of fertilizer because it provides
nutrients (including nitrogen, phosphorus, and potassium) in the least water-
soluble form.
o In general, use 10-4-6 N-P-K (nitrogen-phosphorus-potassium) fertilizer at a rate
of 90 pounds per acre. Always use slow-release fertilizers because they are
more efficient and have fewer environmental impacts. Do not add fertilizer to the
hydromulch machine, or agitate, more than 20 minutes before use. Too much
agitation destroys the slow-release coating.
o There are numerous products available that take the place of chemical fertilizers.
These include several with seaweed extracts that are beneficial to soil microbes
and organisms. If 100 percent cottonseed meal is used as the mulch in
hydroseed, chemical fertilizer may not be necessary. Cottonseed meal provides
a good source of long-term, slow-release, available nitrogen.
Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix:
o On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber
Matrix (MBFM) products. Apply BFM/MBFM products at a minimum rate of 3,000
pounds per acre of mulch with approximately 10 percent tackifier. Achieve a
minimum of 95 percent soil coverage during application. Numerous products are
available commercially. Installed products per manufacturer’s instructions. Most
products require 24-36 hours to cure before rainfall and cannot be installed on
wet or saturated soils. Generally, products come in 40-50 pound bags and
include all necessary ingredients except for seed and fertilizer.
o BFMs and MBFMs provide good alternatives to blankets in most areas requiring
vegetation establishment. Advantages over blankets include:
BFM and MBFMs do not require surface preparation.
Helicopters can assist in installing BFM and MBFMs in remote areas.
On slopes steeper than 2.5H:1V, blanket installers may require ropes and
harnesses for safety.
Installing BFM and MBFMs can save at least $1,000 per acre compared
to blankets.
Maintenance Standards
Reseed any seeded areas that fail to establish at least 80 percent cover (100 percent cover for
areas that receive sheet or concentrated flows). If reseeding is ineffective, use an alternate
method such as sodding, mulching, or nets/blankets. If winter weather prevents adequate grass
growth, this time limit may be relaxed at the discretion of the local authority when sensitive
areas would otherwise be protected.
Reseed and protect by mulch any areas that experience erosion after achieving
adequate cover. Reseed and protect by mulch any eroded area.
Supply seeded areas with adequate moisture, but do not water to the extent that it
causes runoff.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C120: Temporary and
Permanent Seeding. The products did not pass through the Technology Assessment Protocol –
Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as
equivalent, or may require additional testing prior to consideration for local use. The products
are available for review on Ecology’s website
at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html.
BMP C121: Mulching
Purpose
Mulching soils provides immediate temporary protection from erosion. Mulch also enhances
plant establishment by conserving moisture, holding fertilizer, seed, and topsoil in place, and
moderating soil temperatures. There is an enormous variety of mulches that can be used. This
section discusses only the most common types of mulch.
Conditions of Use
As a temporary cover measure, mulch should be used:
For less than 30 days on disturbed areas that require cover.
At all times for seeded areas, especially during the wet season and during the hot
summer months.
During the wet season on slopes steeper than 3H:1V with more than 10 feet of vertical
relief.
Mulch may be applied at any time of the year and must be refreshed periodically.
For seeded areas mulch may be made up of 100 percent: cottonseed meal; fibers made
of wood, recycled cellulose, hemp, kenaf; compost; or blends of these. Tackifier shall be
plant-based, such as guar or alpha plantago, or chemical-based such as polyacrylamide
or polymers. Any mulch or tackifier product used shall be installed per manufacturer’s
instructions. Generally, mulches come in 40-50 pound bags. Seed and fertilizer are
added at time of application.
Design and Installation Specifications
For mulch materials, application rates, and specifications, see Table II-4.1.8 Mulch Standards
and Guidelines. Always use a 2-inch minimum mulch thickness; increase the thickness until the
ground is 95% covered (i.e. not visible under the mulch layer). Note: Thickness may be
increased for disturbed areas in or near sensitive areas or other areas highly susceptible to
erosion.
Where the option of “Compost” is selected, it should be a coarse compost that meets the
following size gradations when tested in accordance with the U.S. Composting Council “Test
Methods for the Examination of Compost and Composting” (TMECC) Test Method 02.02-B.
Coarse Compost
Minimum Percent passing 3” sieve openings 100%
Minimum Percent passing 1” sieve openings 90%
Minimum Percent passing ¾” sieve openings 70%
Minimum Percent passing ¼” sieve openings 40%
Mulch used within the ordinary high-water mark of surface waters should be selected to
minimize potential flotation of organic matter. Composted organic materials have higher specific
gravities (densities) than straw, wood, or chipped material. Consult Hydraulic Permit Authority
(HPA) for mulch mixes if applicable.
Maintenance Standards
The thickness of the cover must be maintained.
Any areas that experience erosion shall be remulched and/or protected with a net or
blanket. If the erosion problem is drainage related, then the problem shall be fixed and
the eroded area remulched.
Table II-4.1.8 Mulch Standards and Guidelines
Mulch
Material Quality Standards Application
Rates Remarks
Straw
Air-dried; free from
undesirable seed
and coarse
material.
2"-3" thick; 5
bales per
1,000 sf or 2-
3 tons per
acre
Cost-effective protection when applied with adequate
thickness. Hand-application generally requires greater
thickness than blown straw. The thickness of straw may be
reduced by half when used in conjunction with seeding. In
windy areas straw must be held in place by crimping, using
a tackifier, or covering with netting. Blown straw always
has to be held in place with a tackifier as even light winds
will blow it away. Straw, however, has several deficiencies
that should be considered when selecting mulch materials.
It often introduces and/or encourages the propagation of
Table II-4.1.8 Mulch Standards and Guidelines
Mulch
Material Quality Standards Application
Rates Remarks
weed species and it has no significant long-term benefits It
should also not be used within the ordinary high-water
elevation of surface waters (due to flotation).
Hydromulch No growth
inhibiting factors.
Approx. 25-30
lbs per 1,000
sf or 1,500 -
2,000 lbs per
acre
Shall be applied with hydromulcher. Shall not be used
without seed and tackifier unless the application rate is at
least doubled. Fibers longer than about 3/4 - 1 inch clog
hydromulch equipment. Fibers should be kept to less than
3/4 inch.
Compost
No visible water or
dust during
handling. Must be
produced per WAC
173-350, Solid
Waste Handling
Standards, but
may have up to
35% biosolids.
2" thick min.;
approx. 100
tons per acre
(approx. 800
lbs per yard)
More effective control can be obtained by increasing
thickness to 3". Excellent mulch for protecting final grades
until landscaping because it can be directly seeded or tilled
into soil as an amendment. Compost used for mulch has a
coarser size gradation than compost used for BMP C125:
Topsoiling / Composting or BMP T5.13: Post-Construction
Soil Quality and Depth. It is more stable and practical to
use in wet areas and during rainy weather conditions. Do
not use near wetlands or near phosphorous impaired water
bodies.
Chipped Site
Vegetation
Average size shall
be several inches.
Gradations from
fines to 6 inches in
length for texture,
variation, and
interlocking
properties.
2" thick min.;
This is a cost-effective way to dispose of debris from
clearing and grubbing, and it eliminates the problems
associated with burning. Generally, it should not be used
on slopes above approx. 10% because of its tendency to
be transported by runoff. It is not recommended within 200
feet of surface waters. If seeding is expected shortly after
mulch, the decomposition of the chipped vegetation may
tie up nutrients important to grass establishment.
Wood-based
Mulch or
Wood Straw
No visible water or
dust during
handling. Must be
purchased from a
supplier with a
Solid Waste
Handling Permit or
one exempt from
solid waste
regulations.
2" thick min.;
approx. 100
tons per acre
(approx. 800
lbs. per cubic
yard)
This material is often called "hog or hogged fuel". The
use of mulch ultimately improves the organic matter in the
soil. Special caution is advised regarding the source and
composition of wood-based mulches. Its preparation
typically does not provide any weed seed control, so
evidence of residual vegetation in its composition or known
inclusion of weed plants or seeds should be monitored and
prevented (or minimized).
Wood Strand
Mulch
A blend of loose,
long, thin wood
pieces derived
from native conifer
2" thick min.
Cost-effective protection when applied with adequate
thickness. A minimum of 95-percent of the wood strand
shall have lengths between 2 and 10-inches, with a width
and thickness between 1/16 and 3/8-inches. The mulch
Table II-4.1.8 Mulch Standards and Guidelines
Mulch
Material Quality Standards Application
Rates Remarks
or deciduous trees
with high length-to-
width ratio.
shall not contain resin, tannin, or other compounds in
quantities that would be detrimental to plant life. Sawdust
or wood shavings shall not be used as mulch. (WSDOT
specification (9-14.4(4))
BMP C122: Nets and Blankets
Purpose
Erosion control nets and blankets are intended to prevent erosion and hold seed and mulch in
place on steep slopes and in channels so that vegetation can become well established. In
addition, some nets and blankets can be used to permanently reinforce turf to protect drainage
ways during high flows. Nets (commonly called matting) are strands of material woven into an
open, but high-tensile strength net (for example, coconut fiber matting). Blankets are strands of
material that are not tightly woven, but instead form a layer of interlocking fibers, typically held
together by a biodegradable or photodegradable netting (for example, excelsior or straw
blankets). They generally have lower tensile strength than nets, but cover the ground more
completely. Coir (coconut fiber) fabric comes as both nets and blankets.
Conditions of Use
Erosion control nets and blankets should be used:
To aid permanent vegetated stabilization of slopes 2H:1V or greater and with more than
10 feet of vertical relief.
For drainage ditches and swales (highly recommended). The application of appropriate
netting or blanket to drainage ditches and swales can protect bare soil from channelized
runoff while vegetation is established. Nets and blankets also can capture a great deal of
sediment due to their open, porous structure. Nets and blankets can be used to
permanently stabilize channels and may provide a cost-effective, environmentally
preferable alternative to riprap. 100 percent synthetic blankets manufactured for use in
ditches may be easily reused as temporary ditch liners.
Disadvantages of blankets include:
Surface preparation required.
On slopes steeper than 2.5H:1V, blanket installers may need to be roped and harnessed
for safety.
They cost at least $4,000-6,000 per acre installed.
Advantages of blankets include:
Installation without mobilizing special equipment.
Installation by anyone with minimal training
Installation in stages or phases as the project progresses.
Installers can hand place seed and fertilizer as they progress down the slope.
Installation in any weather.
There are numerous types of blankets that can be designed with various parameters in
mind. Those parameters include: fiber blend, mesh strength, longevity, biodegradability,
cost, and availability.
Design and Installation Specifications
See Figure II-4.1.3 Channel Installation and Figure II-4.1.4 Slope Installation for typical
orientation and installation of blankets used in channels and as slope protection. Note:
these are typical only; all blankets must be installed per manufacturer’s installation
instructions.
Installation is critical to the effectiveness of these products. If good ground contact is not
achieved, runoff can concentrate under the product, resulting in significant erosion.
Installation of Blankets on Slopes:
1. Complete final grade and track walk up and down the slope.
2. Install hydromulch with seed and fertilizer.
3. Dig a small trench, approximately 12 inches wide by 6 inches deep along the top
of the slope.
4. Install the leading edge of the blanket into the small trench and staple
approximately every 18 inches. NOTE: Staples are metal, “U”-shaped, and a
minimum of 6 inches long. Longer staples are used in sandy soils. Biodegradable
stakes are also available.
5. Roll the blanket slowly down the slope as installer walks backwards. NOTE: The
blanket rests against the installer’s legs. Staples are installed as the blanket is
unrolled. It is critical that the proper staple pattern is used for the blanket being
installed. The blanket is not to be allowed to roll down the slope on its own as this
stretches the blanket making it impossible to maintain soil contact. In addition, no
one is allowed to walk on the blanket after it is in place.
6. If the blanket is not long enough to cover the entire slope length, the trailing edge
of the upper blanket should overlap the leading edge of the lower blanket and be
stapled. On steeper slopes, this overlap should be installed in a small trench,
stapled, and covered with soil.
With the variety of products available, it is impossible to cover all the details of
appropriate use and installation. Therefore, it is critical that the design engineer consult
the manufacturer's information and that a site visit takes place in order to ensure that the
product specified is appropriate. Information is also available at the following web sites:
1. WSDOT (Section 3.2.4):
http://www.wsdot.wa.gov/NR/rdonlyres/3B41E087-FA86-4717-932D-
D7A8556CCD57/0/ErosionTrainingManual.pdf
2. Texas Transportation Institute:
http://www.txdot.gov/business/doing_business/product_evaluation/erosion_control
.htm
Use jute matting in conjunction with mulch (BMP C121: Mulching). Excelsior, woven
straw blankets and coir (coconut fiber) blankets may be installed without mulch. There
are many other types of erosion control nets and blankets on the market that may be
appropriate in certain circumstances.
In general, most nets (e.g., jute matting) require mulch in order to prevent erosion
because they have a fairly open structure. Blankets typically do not require mulch
because they usually provide complete protection of the surface.
Extremely steep, unstable, wet, or rocky slopes are often appropriate candidates for use
of synthetic blankets, as are riverbanks, beaches and other high-energy environments. If
synthetic blankets are used, the soil should be hydromulched first.
100-percent biodegradable blankets are available for use in sensitive areas. These
organic blankets are usually held together with a paper or fiber mesh and stitching which
may last up to a year.
Most netting used with blankets is photodegradable, meaning they break down under
sunlight (not UV stabilized). However, this process can take months or years even under
bright sun. Once vegetation is established, sunlight does not reach the mesh. It is not
uncommon to find non-degraded netting still in place several years after installation. This
can be a problem if maintenance requires the use of mowers or ditch cleaning
equipment. In addition, birds and small animals can become trapped in the netting.
Maintenance Standards
Maintain good contact with the ground. Erosion must not occur beneath the net or
blanket.
Repair and staple any areas of the net or blanket that are damaged or not in close
contact with the ground.
Fix and protect eroded areas if erosion occurs due to poorly controlled drainage.
DEPAR TM E N T OF
ECOLOGY
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.1.3
Channel Installation
Revised June 2015
NOT TO SCALE
Source: Clackamas County 2009
Erosion Prevention Planning and
Design Manual
Notes:
1.Check slots to be constructed per manufacturers specifications.
2.Staking or stapling layout per manufacturers specifications.
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State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.1.4
Slope Installation
Revised June 2015
NOT TO SCALE
Notes:
1.Slope surface shall be smooth before placement for
proper soil contact.
2.Stapling pattern as per manufacturer's recommendations.
3.Do not stretch blankets/mattings tight - allow the rolls to
mold to any irregularities.
4.For slopes less than 3H:1V, rolls may be placed in
horizontal strips.
5.If there is a berm at the top of the slope, anchor upslope
of the berm.
6.Lime, fertilize, and seed before installation. Planting of
shrubs, trees, etc. should occur after installation.
Min. 2" overlap
Anchor in 6" x 6" min.
trench and staple at
12" intervals
Min. 6" overlap
Staple overlaps
max. 5" spacing
Bring material down to a level
area, turn the end under 4"
and staple at 12" intervals
BMP C123: Plastic Covering
Purpose
Plastic covering provides immediate, short-term erosion protection to slopes and disturbed
areas.
Conditions of Use
Plastic covering may be used on disturbed areas that require cover measures for less than 30
days, except as stated below.
Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The
relatively rapid breakdown of most polyethylene sheeting makes it unsuitable for long-
term (greater than six months) applications.
Due to rapid runoff caused by plastic covering, do not use this method upslope of areas
that might be adversely impacted by concentrated runoff. Such areas include steep
and/or unstable slopes.
Plastic sheeting may result in increased runoff volumes and velocities, requiring
additional on-site measures to counteract the increases. Creating a trough with wattles
or other material can convey clean water away from these areas.
To prevent undercutting, trench and backfill rolled plastic covering products.
While plastic is inexpensive to purchase, the added cost of installation, maintenance,
removal, and disposal make this an expensive material, up to $1.50-2.00 per square
yard.
Whenever plastic is used to protect slopes install water collection measures at the base
of the slope. These measures include plastic-covered berms, channels, and pipes used
to covey clean rainwater away from bare soil and disturbed areas. Do not mix clean
runoff from a plastic covered slope with dirty runoff from a project.
Other uses for plastic include:
1. Temporary ditch liner.
2. Pond liner in temporary sediment pond.
3. Liner for bermed temporary fuel storage area if plastic is not reactive to the type of
fuel being stored.
4. Emergency slope protection during heavy rains.
5. Temporary drainpipe (“elephant trunk”) used to direct water.
Design and Installation Specifications
Plastic slope cover must be installed as follows:
1. Run plastic up and down slope, not across slope.
2. Plastic may be installed perpendicular to a slope if the slope length is less than 10
feet.
3. Minimum of 8-inch overlap at seams.
4. On long or wide slopes, or slopes subject to wind, tape all seams.
5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top of the
slope and backfill with soil to keep water from flowing underneath.
6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and tie
them together with twine to hold them in place.
7. Inspect plastic for rips, tears, and open seams regularly and repair immediately.
This prevents high velocity runoff from contacting bare soil which causes extreme
erosion.
8. Sandbags may be lowered into place tied to ropes. However, all sandbags must
be staked in place.
Plastic sheeting shall have a minimum thickness of 0.06 millimeters.
If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection
shall be installed at the toe of the slope in order to reduce the velocity of runoff.
Maintenance Standards
Torn sheets must be replaced and open seams repaired.
Completely remove and replace the plastic if it begins to deteriorate due to ultraviolet
radiation.
Completely remove plastic when no longer needed.
Dispose of old tires used to weight down plastic sheeting appropriately.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C123: Plastic
Covering. The products did not pass through the Technology Assessment Protocol – Ecology
(TAPE) process. Local jurisdictions may choose not to accept this product approved as
equivalent, or may require additional testing prior to consideration for local use. The products
are available for review on Ecology’s website
at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html
BMP C130: Surface Roughening
Purpose
Surface roughening aids in the establishment of vegetative cover, reduces runoff velocity,
increases infiltration, and provides for sediment trapping through the provision of a rough soil
surface. Horizontal depressions are created by operating a tiller or other suitable equipment on
the contour or by leaving slopes in a roughened condition by not fine grading them.
Use this BMP in conjunction with other BMPs such as seeding, mulching, or sodding.
Conditions for Use
All slopes steeper than 3H:1V and greater than 5 vertical feet require surface roughening
to a depth of 2 to 4 inches prior to seeding..
Areas that will not be stabilized immediately may be roughened to reduce runoff velocity
until seeding takes place.
Slopes with a stable rock face do not require roughening.
Slopes where mowing is planned should not be excessively roughened.
Design and Installation Specifications
There are different methods for achieving a roughened soil surface on a slope, and the selection
of an appropriate method depends upon the type of slope. Roughening methods include stair-
step grading, grooving, contour furrows, and tracking. See Figure II-4.1.5 Surface Roughening
by Tracking and Contour Furrows for tracking and contour furrows. Factors to be considered in
choosing a method are slope steepness, mowing requirements, and whether the slope is
formed by cutting or filling.
Disturbed areas that will not require mowing may be stair-step graded, grooved, or left
rough after filling.
Stair-step grading is particularly appropriate in soils containing large amounts of soft
rock. Each "step" catches material that sloughs from above, and provides a level site
where vegetation can become established. Stairs should be wide enough to work with
standard earth moving equipment. Stair steps must be on contour or gullies will form on
the slope.
Areas that will be mowed (these areas should have slopes less steep than 3H:1V) may
have small furrows left by disking, harrowing, raking, or seed-planting machinery
operated on the contour.
Graded areas with slopes steeper than 3H:1V but less than 2H:1V should be roughened
before seeding. This can be accomplished in a variety of ways, including "track walking,"
or driving a crawler tractor up and down the slope, leaving a pattern of cleat imprints
parallel to slope contours.
Tracking is done by operating equipment up and down the slope to leave horizontal
depressions in the soil.
Maintenance Standards
Areas that are graded in this manner should be seeded as quickly as possible.
Regular inspections should be made of the area. If rills appear, they should be re-graded
and re-seeded immediately.
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limitation of liability, and disclaimer.
Figure II-4.1.5
Surface Roughening by Tracking
and Contour Furrows
Revised June 2015
NOT TO SCALE
Tracking
Tracking with machinery up and down
the slope provides grooves that will
catch seed, rainfall, and reduce runoff.
Contour Furrows
50'
(15m)
6" min
(150mm)
Grooves will catch seed, fertilizer,
mulch, rainfall, and decrease runoff.
3
1
Maximum
BMP C140: Dust Control
Purpose
Dust control prevents wind transport of dust from disturbed soil surfaces onto roadways,
drainage ways, and surface waters.
Conditions of Use
In areas (including roadways) subject to surface and air movement of dust where on-site
and off-site impacts to roadways, drainage ways, or surface waters are likely.
Design and Installation Specifications
Vegetate or mulch areas that will not receive vehicle traffic. In areas where planting,
mulching, or paving is impractical, apply gravel or landscaping rock.
Limit dust generation by clearing only those areas where immediate activity will take
place, leaving the remaining area(s) in the original condition. Maintain the original
ground cover as long as practical.
Construct natural or artificial windbreaks or windscreens. These may be designed as
enclosures for small dust sources.
Sprinkle the site with water until surface is wet. Repeat as needed. To prevent carryout
of mud onto street, refer to BMP C105: Stabilized Construction Entrance / Exit.
Irrigation water can be used for dust control. Irrigation systems should be installed as a
first step on sites where dust control is a concern.
Spray exposed soil areas with a dust palliative, following the manufacturer’s instructions
and cautions regarding handling and application. Used oil is prohibited from use as a
dust suppressant. Local governments may approve other dust palliatives such as
calcium chloride or PAM.
PAM (BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection) added to water at a
rate of 0.5 lbs. per 1,000 gallons of water per acre and applied from a water truck is
more effective than water alone. This is due to increased infiltration of water into the soil
and reduced evaporation. In addition, small soil particles are bonded together and are
not as easily transported by wind. Adding PAM may actually reduce the quantity of water
needed for dust control. Use of PAM could be a cost-effective dust control method.
Techniques that can be used for unpaved roads and lots include:
Lower speed limits. High vehicle speed increases the amount of dust stirred up from
unpaved roads and lots.
Upgrade the road surface strength by improving particle size, shape, and mineral types
that make up the surface and base materials.
Add surface gravel to reduce the source of dust emission. Limit the amount of fine
particles (those smaller than .075 mm) to 10 to 20 percent.
Use geotextile fabrics to increase the strength of new roads or roads undergoing
reconstruction.
Encourage the use of alternate, paved routes, if available.
Restrict use of paved roadways by tracked vehicles and heavy trucks to prevent damage
to road surface and base.
Apply chemical dust suppressants using the admix method, blending the product with
the top few inches of surface material. Suppressants may also be applied as surface
treatments.
Pave unpaved permanent roads and other trafficked areas.
Use vacuum street sweepers.
Remove mud and other dirt promptly so it does not dry and then turn into dust.
Limit dust-causing work on windy days.
Contact your local Air Pollution Control Authority for guidance and training on other dust
control measures. Compliance with the local Air Pollution Control Authority constitutes
compliance with this BMP.
Maintenance Standards
Respray area as necessary to keep dust to a minimum.
BMP C150: Materials on Hand
Purpose
Keep quantities of erosion prevention and sediment control materials on the project site at all
times to be used for regular maintenance and emergency situations such as unexpected heavy
summer rains. Having these materials on-site reduces the time needed to implement BMPs
when inspections indicate that existing BMPs are not meeting the Construction SWPPP
requirements. In addition, contractors can save money by buying some materials in bulk and
storing them at their office or yard.
Conditions of Use
Construction projects of any size or type can benefit from having materials on hand. A
small commercial development project could have a roll of plastic and some gravel
available for immediate protection of bare soil and temporary berm construction. A large
earthwork project, such as highway construction, might have several tons of straw,
several rolls of plastic, flexible pipe, sandbags, geotextile fabric and steel “T” posts.
Materials are stockpiled and readily available before any site clearing, grubbing, or
earthwork begins. A large contractor or developer could keep a stockpile of materials
that are available for use on several projects.
If storage space at the project site is at a premium, the contractor could maintain the
materials at their office or yard. The office or yard must be less than an hour from the
project site.
Design and Installation Specifications
Depending on project type, size, complexity, and length, materials and quantities will vary. A
good minimum list of items that will cover numerous situations includes:
Material
Clear Plastic, 6 mil
Drainpipe, 6 or 8 inch diameter
Sandbags, filled
Straw Bales for mulching,
Quarry Spalls
Washed Gravel
Geotextile Fabric
Catch Basin Inserts
Steel "T" Posts
Silt fence material
Straw Wattles
Maintenance Standards
All materials with the exception of the quarry spalls, steel “T” posts, and gravel should be
kept covered and out of both sun and rain.
Re-stock materials used as needed.
BMP C151: Concrete Handling
Purpose
Concrete work can generate process water and slurry that contain fine particles and high pH,
both of which can violate water quality standards in the receiving water. Concrete spillage or
concrete discharge to surface waters of the State is prohibited. Use this BMP to minimize and
eliminate concrete, concrete process water, and concrete slurry from entering waters of the
state.
Conditions of Use
Any time concrete is used, utilize these management practices. Concrete construction projects
include, but are not limited to, the following:
Curbs
Sidewalks
Roads
Bridges
Foundations
Floors
Runways
Design and Installation Specifications
Assure that washout of concrete trucks, chutes, pumps, and internals is performed at an
approved off-site location or in designated concrete washout areas. Do not wash out
concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams.
Refer to BMP C154: Concrete Washout Area for information on concrete washout areas.
Return unused concrete remaining in the truck and pump to the originating batch plant
for recycling. Do not dump excess concrete on site, except in designated concrete
washout areas.
Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and
trowels into formed areas only.
Wash equipment difficult to move, such as concrete pavers in areas that do not directly
drain to natural or constructed stormwater conveyances.
Do not allow washdown from areas, such as concrete aggregate driveways, to drain
directly to natural or constructed stormwater conveyances.
Contain washwater and leftover product in a lined container when no formed areas are
available. Dispose of contained concrete in a manner that does not violate ground water
or surface water quality standards.
Always use forms or solid barriers for concrete pours, such as pilings, within 15-feet of
surface waters.
Refer to BMP C252: High pH Neutralization Using CO2 and BMP C253: pH Control for
High pH Water for pH adjustment requirements.
Refer to the Construction Stormwater General Permit for pH monitoring requirements if
the project involves one of the following activities:
o Significant concrete work (greater than 1,000 cubic yards poured concrete or
recycled concrete used over the life of a project).
o The use of engineered soils amended with (but not limited to) Portland cement-
treated base, cement kiln dust or fly ash.
o Discharging stormwater to segments of water bodies on the 303(d) list (Category
5) for high pH.
Maintenance Standards
Check containers for holes in the liner daily during concrete pours and repair the same day.
BMP C152: Sawcutting and Surfacing Pollution
Prevention
Purpose
Sawcutting and surfacing operations generate slurry and process water that contains fine
particles and high pH (concrete cutting), both of which can violate the water quality standards in
the receiving water. Concrete spillage or concrete discharge to surface waters of the State is
prohibited. Use this BMP to minimize and eliminate process water and slurry created through
sawcutting or surfacing from entering waters of the State.
Conditions of Use
Utilize these management practices anytime sawcutting or surfacing operations take place.
Sawcutting and surfacing operations include, but are not limited to, the following:
Sawing
Coring
Grinding
Roughening
Hydro-demolition
Bridge and road surfacing
Design and Installation Specifications
Vacuum slurry and cuttings during cutting and surfacing operations.
Slurry and cuttings shall not remain on permanent concrete or asphalt pavement
overnight.
Slurry and cuttings shall not drain to any natural or constructed drainage conveyance
including stormwater systems. This may require temporarily blocking catch basins.
Dispose of collected slurry and cuttings in a manner that does not violate ground water
or surface water quality standards.
Do not allow process water generated during hydro-demolition, surface roughening or
similar operations to drain to any natural or constructed drainage conveyance including
stormwater systems. Dispose process water in a manner that does not violate ground
water or surface water quality standards.
Handle and dispose cleaning waste material and demolition debris in a manner that
does not cause contamination of water. Dispose of sweeping material from a pick-up
sweeper at an appropriate disposal site.
Maintenance Standards
Continually monitor operations to determine whether slurry, cuttings, or process water could
enter waters of the state. If inspections show that a violation of water quality standards could
occur, stop operations and immediately implement preventive measures such as berms,
barriers, secondary containment, and vacuum trucks.
BMP C200: Interceptor Dike and Swale
Purpose
Provide a ridge of compacted soil, or a ridge with an upslope swale, at the top or base of a
disturbed slope or along the perimeter of a disturbed construction area to convey stormwater.
Use the dike and/or swale to intercept the runoff from unprotected areas and direct it to areas
where erosion can be controlled. This can prevent storm runoff from entering the work area or
sediment-laden runoff from leaving the construction site.
Conditions of Use
Where the runoff from an exposed site or disturbed slope must be conveyed to an erosion
control facility which can safely convey the stormwater.
Locate upslope of a construction site to prevent runoff from entering disturbed area.
When placed horizontally across a disturbed slope, it reduces the amount and velocity of
runoff flowing down the slope.
Locate downslope to collect runoff from a disturbed area and direct water to a sediment
basin.
Design and Installation Specifications
Dike and/or swale and channel must be stabilized with temporary or permanent
vegetation or other channel protection during construction.
Channel requires a positive grade for drainage; steeper grades require channel
protection and check dams.
Review construction for areas where overtopping may occur.
Can be used at top of new fill before vegetation is established.
May be used as a permanent diversion channel to carry the runoff.
Sub-basin tributary area should be one acre or less.
Design capacity for the peak volumetric flow rate calculated using a 10-minute time step
from a 10-year, 24-hour storm, assuming a Type 1A rainfall distribution, for temporary
facilities. Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved
continuous runoff model. For facilities that will also serve on a permanent basis, consult
the local government’s drainage requirements.
Interceptor dikes shall meet the following criteria:
Top Width: 2 feet minimum.
Height: 1.5 feet minimum on berm.
Side Slope: 2H:1V or flatter.
Grade: Depends on topography, however, dike system minimum is 0.5%, and maximum
is 1%.
Compaction: Minimum of 90 percent ASTM D698 standard proctor.
Horizontal Spacing of Interceptor Dikes:
Average Slope Slope Percent Flowpath Length
20H:1V or less 3-5% 300 feet
(10 to 20)H:1V 5-10% 200 feet
(4 to 10)H:1V 10-25% 100 feet
(2 to 4)H:1V 25-50% 50 feet
Stabilization: depends on velocity and reach
Slopes <5%: Seed and mulch applied within 5 days of dike construction (see BMP C121:
Mulching).
Slopes 5 - 40%: Dependent on runoff velocities and dike materials. Stabilization should
be done immediately using either sod or riprap or other measures to avoid erosion.
The upslope side of the dike shall provide positive drainage to the dike outlet. No erosion
shall occur at the outlet. Provide energy dissipation measures as necessary. Sediment-
laden runoff must be released through a sediment trapping facility.
Minimize construction traffic over temporary dikes. Use temporary cross culverts for
channel crossing.
Interceptor swales shall meet the following criteria:
Bottom Width: 2 feet minimum; the cross-section bottom shall be level.
Depth: 1-foot minimum.
Side Slope: 2H:1V or flatter.
Grade: Maximum 5 percent, with positive drainage to a suitable outlet (such as a
sediment pond).
Stabilization: Seed as per BMP C120: Temporary and Permanent Seeding, or BMP
C202: Channel Lining, 12 inches thick riprap pressed into the bank and extending at
least 8 inches vertical from the bottom.
Inspect diversion dikes and interceptor swales once a week and after every rainfall. Immediately
remove sediment from the flow area.
Damage caused by construction traffic or other activity must be repaired before the end of each
working day.
Check outlets and make timely repairs as needed to avoid gully formation. When the area below
the temporary diversion dike is permanently stabilized, remove the dike and fill and stabilize the
channel to blend with the natural surface.
BMP C206: Level Spreader
Purpose
To provide a temporary outlet for dikes and diversions consisting of an excavated depression
constructed at zero grade across a slope. To convert concentrated runoff to sheet flow and
release it onto areas stabilized by existing vegetation or an engineered filter strip.
Conditions of Use
Used when a concentrated flow of water needs to be dispersed over a large area with existing
stable vegetation.
Items to consider are:
1. What is the risk of erosion or damage if the flow may become concentrated?
2. Is an easement required if discharged to adjoining property?
3. Most of the flow should be as ground water and not as surface flow.
4. Is there an unstable area downstream that cannot accept additional ground water?
Use only where the slopes are gentle, the water volume is relatively low, and the soil will
adsorb most of the low flow events.
Design and Installation Specifications
Use above undisturbed areas that are stabilized by existing vegetation.
If the level spreader has any low points, flow will concentrate, create channels and may cause
erosion.
Discharge area below the outlet must be uniform with a slope flatter than 5H:1V.
Outlet to be constructed level in a stable, undisturbed soil profile (not on fill).
The runoff shall not re-concentrate after release unless intercepted by another
downstream measure.
The grade of the channel for the last 20 feet of the dike or interceptor entering the level
spreader shall be less than or equal to 1 percent. The grade of the level spreader shall
be 0 percent to ensure uniform spreading of storm runoff.
A 6-inch high gravel berm placed across the level lip shall consist of washed crushed
rock, 2- to 4-inch or 3/4-inch to 1½-inch size.
The spreader length shall be determined by estimating the peak flow expected from the
10-year, 24-hour design storm. The length of the spreader shall be a minimum of 15 feet
for 0.1 cfs and shall increase by 10 feet for each 0.1 cfs thereafter to a maximum of 0.5
cfs per spreader. Use multiple spreaders for higher flows.
The width of the spreader should be at least 6 feet.
The depth of the spreader as measured from the lip should be at least 6 inches and it
should be uniform across the entire length.
Level spreaders shall be setback from the property line unless there is an easement for
flow.
Level spreaders, when installed every so often in grassy swales, keep the flows from
concentrating. Materials that can be used include sand bags, lumber, logs, concrete, and
pipe. To function properly, the material needs to be installed level and on contour. BMP
C206: Level Spreader and Figure II-4.2.6 Detail of Level Spreader provide a cross-
section and a detail of a level spreader. A capped perforated pipe could also be used as
a spreader.
Maintenance Standards
The spreader should be inspected after every runoff event to ensure that it is functioning
correctly.
The contractor should avoid the placement of any material on the structure and should
prevent construction traffic from crossing over the structure.
If the spreader is damaged by construction traffic, it shall be immediately repaired.
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Figure II-4.2.5
Cross Section of Level Spreader
Revised July 2015
NOT TO SCALE
Densely vegetated for a min. of
100' and slope less than 5:1
Pressure-treated 2"x10"
2:1
Max.
1' Min.
3' Min.
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Figure II-4.2.6
Detail of Level Spreader
Revised July 2015
NOT TO SCALE
Spreader must be level
6" min.
6" min.
Treated 2" x 10" may be abutted end
to end for max. spreader length of 50'
1" min.
18" min. rebar supports
8' max. spacing
BMP C207: Check Dams
Purpose
Construction of small dams across a swale or ditch reduces the velocity of concentrated flow
and dissipates energy at the check dam.
Conditions of Use
Where temporary channels or permanent channels are not yet vegetated, channel lining is
infeasible, and/or velocity checks are required.
Check dams may not be placed in streams unless approved by the State Department of
Fish and Wildlife. Check dams may not be placed in wetlands without approval from a
permitting agency.
Do not place check dams below the expected backwater from any salmonid bearing
water between October 1 and May 31 to ensure that there is no loss of high flow refuge
habitat for overwintering juvenile salmonids and emergent salmonid fry.
Construct rock check dams from appropriately sized rock. The rock used must be large
enough to stay in place given the expected design flow through the channel. The rock
must be placed by hand or by mechanical means (no dumping of rock to form dam) to
achieve complete coverage of the ditch or swale and to ensure that the center of the
dam is lower than the edges.
Check dams may also be constructed of either rock or pea-gravel filled bags. Numerous
new products are also available for this purpose. They tend to be re-usable, quick and
easy to install, effective, and cost efficient.
Place check dams perpendicular to the flow of water.
The dam should form a triangle when viewed from the side. This prevents undercutting
as water flows over the face of the dam rather than falling directly onto the ditch bottom.
Before installing check dams impound and bypass upstream water flow away from the
work area. Options for bypassing include pumps, siphons, or temporary channels.
Check dams in association with sumps work more effectively at slowing flow and
retaining sediment than just a check dam alone. A deep sump should be provided
immediately upstream of the check dam.
In some cases, if carefully located and designed, check dams can remain as permanent
installations with very minor regrading. They may be left as either spillways, in which
case accumulated sediment would be graded and seeded, or as check dams to prevent
further sediment from leaving the site.
The maximum spacing between the dams shall be such that the toe of the upstream
dam is at the same elevation as the top of the downstream dam.
Keep the maximum height at 2 feet at the center of the dam.
Keep the center of the check dam at least 12 inches lower than the outer edges at
natural ground elevation.
Keep the side slopes of the check dam at 2H:1V or flatter.
Key the stone into the ditch banks and extend it beyond the abutments a minimum of 18
inches to avoid washouts from overflow around the dam.
Use filter fabric foundation under a rock or sand bag check dam. If a blanket ditch liner is
used, filter fabric is not necessary. A piece of organic or synthetic blanket cut to fit will
also work for this purpose.
In the case of grass-lined ditches and swales, all check dams and accumulated
sediment shall be removed when the grass has matured sufficiently to protect the ditch
or swale - unless the slope of the swale is greater than 4 percent. The area beneath the
check dams shall be seeded and mulched immediately after dam removal.
Ensure that channel appurtenances, such as culvert entrances below check dams, are
not subject to damage or blockage from displaced stones. Figure II-4.2.7 Rock Check
Dam depicts a typical rock check dam.
Maintenance Standards
Check dams shall be monitored for performance and sediment accumulation during and after
each runoff producing rainfall. Sediment shall be removed when it reaches one half the sump
depth.
Anticipate submergence and deposition above the check dam and erosion from high
flows around the edges of the dam.
If significant erosion occurs between dams, install a protective riprap liner in that portion
of the channel.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C207: Check Dams.
The products did not pass through the Technology Assessment Protocol – Ecology (TAPE)
process. Local jurisdictions may choose not to accept this product approved as equivalent, or
may require additional testing prior to consideration for local use. The products are available for
review on Ecology’s website
at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html
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Figure II-4.2.7
Rock Check Dam
Revised July 2015
NOT TO SCALE
View Looking Upstream
Section A-A
Spacing Between Check Dams
Note:
Key stone into channel banks and extend it
beyond the abutments a minimum of 18"
(0.5m) to prevent flow around dam.
A
A
12"
(150mm)
18"
(0.5m)
24" (0.6m)
Flow 24" (0.6m)
8' (2.4m)
Point 'A'Point 'B'
'L'
'L' = the distance such that points
'A' and 'B' are of equal elevation.
BMP C209: Outlet Protection
Purpose
Outlet protection prevents scour at conveyance outlets and minimizes the potential for
downstream erosion by reducing the velocity of concentrated stormwater flows.
Conditions of Use
Outlet protection is required at the outlets of all ponds, pipes, ditches, or other conveyances,
and where runoff is conveyed to a natural or manmade drainage feature such as a stream,
wetland, lake, or ditch.
Design and Installation Specifications
The receiving channel at the outlet of a culvert shall be protected from erosion by rock lining a
minimum of 6 feet downstream and extending up the channel sides a minimum of 1–foot above
the maximum tailwater elevation or 1-foot above the crown, whichever is higher. For large pipes
(more than 18 inches in diameter), the outlet protection lining of the channel is lengthened to
four times the diameter of the culvert.
Standard wingwalls, and tapered outlets and paved channels should also be considered
when appropriate for permanent culvert outlet protection. (See WSDOT Hydraulic
Manual, available through WSDOT Engineering Publications).
Organic or synthetic erosion blankets, with or without vegetation, are usually more
effective than rock, cheaper, and easier to install. Materials can be chosen using
manufacturer product specifications. ASTM test results are available for most products
and the designer can choose the correct material for the expected flow.
With low flows, vegetation (including sod) can be effective.
The following guidelines shall be used for riprap outlet protection:
1. If the discharge velocity at the outlet is less than 5 fps (pipe slope less than 1
percent), use 2-inch to 8-inch riprap. Minimum thickness is 1-foot.
2. For 5 to 10 fps discharge velocity at the outlet (pipe slope less than 3 percent),
use 24-inch to 48-inch riprap. Minimum thickness is 2 feet.
3. For outlets at the base of steep slope pipes (pipe slope greater than 10 percent),
an engineered energy dissipater shall be used.
Filter fabric or erosion control blankets should always be used under riprap to prevent
scour and channel erosion.
New pipe outfalls can provide an opportunity for low-cost fish habitat improvements. For
example, an alcove of low-velocity water can be created by constructing the pipe outfall
and associated energy dissipater back from the stream edge and digging a channel,
over-widened to the upstream side, from the outfall. Overwintering juvenile and migrating
adult salmonids may use the alcove as shelter during high flows. Bank stabilization,
bioengineering, and habitat features may be required for disturbed areas. This work may
require a HPA. See Volume V for more information on outfall system design.
Maintenance Standards
Inspect and repair as needed.
Add rock as needed to maintain the intended function.
Clean energy dissipater if sediment builds up.
BMP C220: Storm Drain Inlet Protection
Purpose
Storm drain inlet protection prevents coarse sediment from entering drainage systems prior to
permanent stabilization of the disturbed area.
Conditions of Use
Use storm drain inlet protection at inlets that are operational before permanent stabilization of
the disturbed drainage area. Provide protection for all storm drain inlets downslope and within
500 feet of a disturbed or construction area, unless conveying runoff entering catch basins to a
sediment pond or trap.
Also consider inlet protection for lawn and yard drains on new home construction. These small
and numerous drains coupled with lack of gutters in new home construction can add significant
amounts of sediment into the roof drain system. If possible delay installing lawn and yard drains
until just before landscaping or cap these drains to prevent sediment from entering the system
until completion of landscaping. Provide 18-inches of sod around each finished lawn and yard
drain.
Table II-4.2.2 Storm Drain Inlet Protection lists several options for inlet protection. All of the
methods for storm drain inlet protection tend to plug and require a high frequency of
maintenance. Limit drainage areas to one acre or less. Possibly provide emergency overflows
with additional end-of-pipe treatment where stormwater ponding would cause a hazard.
Table II-4.2.2 Storm Drain Inlet Protection
Type of Inlet
Protection
Emergency
Overflow
Applicable for
Paved/ Earthen
Surfaces
Conditions of Use
Drop Inlet Protection
Excavated drop
inlet protection
Yes, temporary
flooding will occur Earthen
Applicable for heavy flows. Easy
to maintain. Large area
Requirement: 30'x30'/acre
Block and gravel
drop inlet
protection
Yes Paved or Earthen Applicable for heavy concentrated
flows. Will not pond.
Gravel and wire
drop inlet
protection
No
Applicable for heavy concentrated
flows. Will pond. Can withstand
traffic.
Catch basin filters Yes Paved or Earthen Frequent Maintenance required.
Curb Inlet Protection
Curb inlet
protection with
wooden weir
Small capacity
overflow Paved Used for sturdy, more compact
installation.
Block and gravel
curb inlet
protection
Yes Paved Sturdy, but limited filtration.
Culvert Inlet Protection
Culvert inlet
Sediment trap 18 month expected life.
Design and Installation Specifications
Excavated Drop Inlet Protection - An excavated impoundment around the storm drain. Sediment
settles out of the stormwater prior to entering the storm drain.
Provide a depth of 1-2 ft as measured from the crest of the inlet structure.
Slope sides of excavation no steeper than 2H:1V.
Minimum volume of excavation 35 cubic yards.
Shape basin to fit site with longest dimension oriented toward the longest inflow area.
Install provisions for draining to prevent standing water problems.
Clear the area of all debris.
Grade the approach to the inlet uniformly.
Drill weep holes into the side of the inlet.
Protect weep holes with screen wire and washed aggregate.
Seal weep holes when removing structure and stabilizing area.
Build a temporary dike, if necessary, to the down slope side of the structure to prevent
bypass flow.
Block and Gravel Filter - A barrier formed around the storm drain inlet with standard concrete
blocks and gravel. See Figure II-4.2.8 Block and Gravel Filter.
Provide a height of 1 to 2 feet above inlet.
Recess the first row 2-inches into the ground for stability.
Support subsequent courses by placing a 2x4 through the block opening.
Do not use mortar.
Lay some blocks in the bottom row on their side for dewatering the pool.
Place hardware cloth or comparable wire mesh with ½-inch openings over all block
openings.
Place gravel just below the top of blocks on slopes of 2H:1V or flatter.
An alternative design is a gravel donut.
Provide an inlet slope of 3H:1V.
Provide an outlet slope of 2H:1V.
Provide a1-foot wide level stone area between the structure and the inlet.
Use inlet slope stones 3 inches in diameter or larger.
Use gravel ½- to ¾-inch at a minimum thickness of 1-foot for the outlet slope.
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Figure II-4.2.8
Block and Gravel Filter
Revised August 2015
NOT TO SCALE
Plan View
A
A
Section A-A
Drain grate
Concrete block
Gravel backfill
Less than5% slope
Gravel backfill
Concrete block
Water
Overflow
water
Drop inlet
Ponding height
Wire screen or
filter fabric
Notes:
1.Drop inlet sediment barriers are to be used for small, nearly level drainage areas. (less
than 5%)
2.Excavate a basin of sufficient size adjacent to the drop inlet.
3.The top of the structure (ponding height) must be well below the ground elevation
downslope to prevent runoff from bypassing the inlet. A temporary dike may be
necessary on the downslope side of the structure.
Gravel and Wire Mesh Filter - A gravel barrier placed over the top of the inlet. This structure
does not provide an overflow.
Use a hardware cloth or comparable wire mesh with ½-inch openings.
Use coarse aggregate.
Provide a height 1-foot or more, 18-inches wider than inlet on all sides.
Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot beyond
each side of the inlet structure.
Overlap the strips if more than one strip of mesh is necessary.
Place coarse aggregate over the wire mesh.
Provide at least a 12-inch depth of gravel over the entire inlet opening and extend at
least 18-inches on all sides.
Catchbasin Filters – Use inserts designed by manufacturers for construction sites. The limited
sediment storage capacity increases the amount of inspection and maintenance required, which
may be daily for heavy sediment loads. To reduce maintenance requirements combine a
catchbasin filter with another type of inlet protection. This type of inlet protection provides flow
bypass without overflow and therefore may be a better method for inlets located along active
rights-of-way.
Provides 5 cubic feet of storage.
Requires dewatering provisions.
Provides a high-flow bypass that will not clog under normal use at a construction site.
Insert the catchbasin filter in the catchbasin just below the grating.
Curb Inlet Protection with Wooden Weir – Barrier formed around a curb inlet with a wooden
frame and gravel.
Use wire mesh with ½-inch openings.
Use extra strength filter cloth.
Construct a frame.
Attach the wire and filter fabric to the frame.
Pile coarse washed aggregate against wire/fabric.
Place weight on frame anchors.
Block and Gravel Curb Inlet Protection – Barrier formed around a curb inlet with concrete blocks
and gravel. See Figure II-4.2.9 Block and Gravel Curb Inlet Protection.
Use wire mesh with ½-inch openings.
Place two concrete blocks on their sides abutting the curb at either side of the inlet
opening. These are spacer blocks.
Place a 2x4 stud through the outer holes of each spacer block to align the front blocks.
Place blocks on their sides across the front of the inlet and abutting the spacer blocks.
Place wire mesh over the outside vertical face.
Pile coarse aggregate against the wire to the top of the barrier.
Curb and Gutter Sediment Barrier – Sandbag or rock berm (riprap and aggregate) 3 feet high
and 3 feet wide in a horseshoe shape. See Figure II-4.2.10 Curb and Gutter Barrier.
Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet
high and 3 feet wide, at least 2 feet from the inlet.
Construct a horseshoe shaped sedimentation trap on the outside of the berm sized to
sediment trap standards for protecting a culvert inlet.
Maintenance Standards
Inspect catch basin filters frequently, especially after storm events. Clean and replace
clogged inserts. For systems with clogged stone filters: pull away the stones from the
inlet and clean or replace. An alternative approach would be to use the clogged stone as
fill and put fresh stone around the inlet.
Do not wash sediment into storm drains while cleaning. Spread all excavated material
evenly over the surrounding land area or stockpile and stabilize as appropriate.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C220: Storm Drain
Inlet Protection. The products did not pass through the Technology Assessment Protocol –
Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as
equivalent, or may require additional testing prior to consideration for local use. The products
are available for review on Ecology’s website
at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html
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Figure II-4.2.9
Block and Gravel Curb Inlet Protection
Revised August 2015
NOT TO SCALE
Plan View
A
A
Section A-A
Notes:
1.Use block and gravel type sediment barrier when curb inlet is located in gently sloping street
segment, where water can pond and allow sediment to separate from runoff.
2.Barrier shall allow for overflow from severe storm event.
3.Inspect barriers and remove sediment after each storm event. Sediment and gravel must be
removed from the traveled way immediately.
Back of sidewalk
Catch basin
Back of curb Curb inlet Concrete block
2x4 Wood stud
Concrete block34 inch (20 mm)
Drain gravel
Wire screen or
filter fabric
34 inch (20 mm)
Drain gravel
Wire screen or
filter fabric
Ponding height
Overflow
2x4 Wood stud
(100x50 Timber stud)
Concrete block
Curb inlet
Catch basin
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Figure II-4.2.10
Curb and Gutter Barrier
Revised September 2015
NOT TO SCALE
Plan View
Back of sidewalk
Runoff
Runoff Spillway
Burlap sacks to
overlap onto curb
Gravel filled sandbags
stacked tightly
Curb inlet
Catch basin
Back of curb
Notes:
1.Place curb type sediment barriers on gently sloping street segments, where water can
pond and allow sediment to separate from runoff.
2.Sandbags of either burlap or woven 'geotextile' fabric, are filled with gravel, layered
and packed tightly.
3.Leave a one sandbag gap in the top row to provide a spillway for overflow.
4.Inspect barriers and remove sediment after each storm event. Sediment and gravel
must be removed from the traveled way immediately.
BMP C233: Silt Fence
Purpose
Use of a silt fence reduces the transport of coarse sediment from a construction site by
providing a temporary physical barrier to sediment and reducing the runoff velocities of overland
flow. See Figure II-4.2.12 Silt Fence for details on silt fence construction.
Conditions of Use
Silt fence may be used downslope of all disturbed areas.
Silt fence shall prevent soil carried by runoff water from going beneath, through, or over
the top of the silt fence, but shall allow the water to pass through the fence.
Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial
amounts of overland flow. Convey any concentrated flows through the drainage system
to a sediment pond.
Do not construct silt fences in streams or use in V-shaped ditches. Silt fences do not
provide an adequate method of silt control for anything deeper than sheet or overland
flow.
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Figure II-4.2.12
Silt Fence
Revised October 2014
NOT TO SCALE
Joints in filter fabric shall be spliced
at posts. Use staples, wire rings or
equivalent to attach fabric to posts
6' max
Post spacing may be increased
to 8' if wire backing is used
2"x2" by 14 Ga. wire or equivalent,
if standard strength fabric used
Minimum
4"x4" trench
2"x2" wood posts, steel
fence posts, or equivalent
12" min
2' min
2"x2" by 14 Ga. wire or equivalent,
if standard strength fabric used
Filter fabric
Minimum
4"x4" trench
2"x2" wood posts, steel
fence posts, or equivalent
Backfill trench with
native soil or 34" -
1.5" washed gravel
Design and Installation Specifications
Use in combination with sediment basins or other BMPs.
Maximum slope steepness (normal (perpendicular) to fence line) 1H:1V.
Maximum sheet or overland flow path length to the fence of 100 feet.
Do not allow flows greater than 0.5 cfs.
The geotextile used shall meet the following standards. All geotextile properties listed
below are minimum average roll values (i.e., the test result for any sampled roll in a lot
shall meet or exceed the values shown in Table II-4.2.3 Geotextile Standards):
Table II-4.2.3 Geotextile Standards
Polymeric Mesh AOS
(ASTM D4751)
0.60 mm maximum for slit film woven (#30 sieve).
0.30 mm maximum for all other geotextile types (#50 sieve).
0.15 mm minimum for all fabric types (#100 sieve).
Water Permittivity
(ASTM D4491) 0.02 sec-1 minimum
Grab Tensile Strength
(ASTM D4632)
180 lbs. Minimum for extra strength fabric.
100 lbs minimum for standard strength fabric.
Grab Tensile Strength
(ASTM D4632) 30% maximum
Ultraviolet Resistance
(ASTM D4355) 70% minimum
Support standard strength fabrics with wire mesh, chicken wire, 2-inch x 2-inch wire,
safety fence, or jute mesh to increase the strength of the fabric. Silt fence materials are
available that have synthetic mesh backing attached.
Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to provide a
minimum of six months of expected usable construction life at a temperature range of
0°F. to 120°F.
One-hundred percent biodegradable silt fence is available that is strong, long lasting,
and can be left in place after the project is completed, if permitted by local regulations.
Refer to Figure II-4.2.12 Silt Fence for standard silt fence details. Include the following
standard Notes for silt fence on construction plans and specifications:
1. The contractor shall install and maintain temporary silt fences at the locations
shown in the Plans.
2. Construct silt fences in areas of clearing, grading, or drainage prior to starting
those activities.
3. The silt fence shall have a 2-feet min. and a 2½-feet max. height above the
original ground surface.
4. The filter fabric shall be sewn together at the point of manufacture to form filter
fabric lengths as required. Locate all sewn seams at support posts. Alternatively,
two sections of silt fence can be overlapped, provided the Contractor can
demonstrate, to the satisfaction of the Engineer, that the overlap is long enough
and that the adjacent fence sections are close enough together to prevent silt
laden water from escaping through the fence at the overlap.
5. Attach the filter fabric on the up-slope side of the posts and secure with staples,
wire, or in accordance with the manufacturer's recommendations. Attach the filter
fabric to the posts in a manner that reduces the potential for tearing.
6. Support the filter fabric with wire or plastic mesh, dependent on the properties of
the geotextile selected for use. If wire or plastic mesh is used, fasten the mesh
securely to the up-slope side of the posts with the filter fabric up-slope of the
mesh.
7. Mesh support, if used, shall consist of steel wire with a maximum mesh spacing of
2-inches, or a prefabricated polymeric mesh. The strength of the wire or polymeric
mesh shall be equivalent to or greater than 180 lbs. grab tensile strength. The
polymeric mesh must be as resistant to the same level of ultraviolet radiation as
the filter fabric it supports.
8. Bury the bottom of the filter fabric 4-inches min. below the ground surface. Backfill
and tamp soil in place over the buried portion of the filter fabric, so that no flow can
pass beneath the fence and scouring cannot occur. When wire or polymeric back-
up support mesh is used, the wire or polymeric mesh shall extend into the ground
3-inches min.
9. Drive or place the fence posts into the ground 18-inches min. A 12–inch min.
depth is allowed if topsoil or other soft subgrade soil is not present and 18-inches
cannot be reached. Increase fence post min. depths by 6 inches if the fence is
located on slopes of 3H:1V or steeper and the slope is perpendicular to the fence.
If required post depths cannot be obtained, the posts shall be adequately secured
by bracing or guying to prevent overturning of the fence due to sediment loading.
10. Use wood, steel or equivalent posts. The spacing of the support posts shall be a
maximum of 6-feet. Posts shall consist of either:
Wood with dimensions of 2-inches by 2-inches wide min. and a 3-feet min.
length. Wood posts shall be free of defects such as knots, splits, or
gouges.
No. 6 steel rebar or larger.
ASTM A 120 steel pipe with a minimum diameter of 1-inch.
U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft.
Other steel posts having equivalent strength and bending resistance to the
post sizes listed above.
11. Locate silt fences on contour as much as possible, except at the ends of the
fence, where the fence shall be turned uphill such that the silt fence captures the
runoff water and prevents water from flowing around the end of the fence.
12. If the fence must cross contours, with the exception of the ends of the fence, place
gravel check dams perpendicular to the back of the fence to minimize
concentrated flow and erosion. The slope of the fence line where contours must
be crossed shall not be steeper than 3H:1V.
Gravel check dams shall be approximately 1-foot deep at the back of the
fence. Gravel check dams shall be continued perpendicular to the fence at
the same elevation until the top of the check dam intercepts the ground
surface behind the fence.
Gravel check dams shall consist of crushed surfacing base course, gravel
backfill for walls, or shoulder ballast. Gravel check dams shall be located
every 10 feet along the fence where the fence must cross contours.
Refer to Figure II-4.2.13 Silt Fence Installation by Slicing Method for slicing method
details. Silt fence installation using the slicing method specifications:
1. The base of both end posts must be at least 2- to 4-inches above the top of the
filter fabric on the middle posts for ditch checks to drain properly. Use a hand level
or string level, if necessary, to mark base points before installation.
2. Install posts 3- to 4-feet apart in critical retention areas and 6- to 7-feet apart in
standard applications.
3. Install posts 24-inches deep on the downstream side of the silt fence, and as close
as possible to the filter fabric, enabling posts to support the filter fabric from
upstream water pressure.
4. Install posts with the nipples facing away from the filter fabric.
5. Attach the filter fabric to each post with three ties, all spaced within the top 8-
inches of the filter fabric. Attach each tie diagonally 45 degrees through the filter
fabric, with each puncture at least 1-inch vertically apart. Each tie should be
positioned to hang on a post nipple when tightening to prevent sagging.
6. Wrap approximately 6-inches of fabric around the end posts and secure with 3
ties.
7. No more than 24-inches of a 36-inch filter fabric is allowed above ground level.
Compact the soil immediately next to the filter fabric with the front wheel of the
tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact
the upstream side first and then each side twice for a total of four trips. Check and
correct the silt fence installation for any deviation before compaction. Use a flat-
bladed shovel to tuck fabric deeper into the ground if necessary.
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limitation of liability, and disclaimer.
Figure II-4.2.13
Silt Fence Installation by Slicing Method
Revised November 2015
NOT TO SCALE
Completed Installation
Silt Fence
Post
installed
after
compaction
Vibratory plow is not acceptable because of horizontal compaction
Slicing blade
(18 mm width)
Horizontal chisel point
(76 mm width)
Fabric
above
ground
200 -
300mm
Roll of silt fenceOperation
No more than 24" of a 36"
fabric is allowed above groundSteel support post100% compaction 100% compaction
FLOW
Drive over each side of
silt fence 2 to 4 times
with device exerting 60
p.s.i. or greater
Attach fabric to
upstream side of post
Ponding height max. 24"
POST SPACING:
7' max. on open runs
4' max. on pooling areas
POST DEPTH:
As much below ground
as fabric above ground
Top of Fabric
Belt
top 8"
Diagonal attachment
doubles strength
Attachment Details:
x Gather fabric at posts, if needed.
x Utilize three ties per post, all within top 8"
of fabric.
x Position each tie diagonally, puncturing
holes vertically a minimum of 1" apart.
x Hang each tie on a post nipple and tighten
securely. Use cable ties (50 lbs) or soft
wire.
Maintenance Standards
Repair any damage immediately.
Intercept and convey all evident concentrated flows uphill of the silt fence to a sediment
pond.
Check the uphill side of the fence for signs of the fence clogging and acting as a barrier
to flow and then causing channelization of flows parallel to the fence. If this occurs,
replace the fence or remove the trapped sediment.
Remove sediment deposits when the deposit reaches approximately one-third the height
of the silt fence, or install a second silt fence.
Replace filter fabric that has deteriorated due to ultraviolet breakdown.
BMP C240: Sediment Trap
Purpose
A sediment trap is a small temporary ponding area with a gravel outlet used to collect and store
sediment from sites cleared and/or graded during construction. Sediment traps, along with other
perimeter controls, shall be installed before any land disturbance takes place in the drainage
area.
Conditions of Use
Prior to leaving a construction site, stormwater runoff must pass through a sediment pond or
trap or other appropriate sediment removal best management practice. Non-engineered
sediment traps may be used on-site prior to an engineered sediment trap or sediment pond to
provide additional sediment removal capacity.
It is intended for use on sites where the tributary drainage area is less than 3 acres, with no
unusual drainage features, and a projected build-out time of six months or less. The sediment
trap is a temporary measure (with a design life of approximately 6 months) and shall be
maintained until the site area is permanently protected against erosion by vegetation and/or
structures.
Sediment traps and ponds are only effective in removing sediment down to about the medium
silt size fraction. Runoff with sediment of finer grades (fine silt and clay) will pass through
untreated, emphasizing the need to control erosion to the maximum extent first.
Whenever possible, sediment-laden water shall be discharged into on-site, relatively level,
vegetated areas (see BMP C234: Vegetated Strip). This is the only way to effectively remove
fine particles from runoff unless chemical treatment or filtration is used. This can be particularly
useful after initial treatment in a sediment trap or pond. The areas of release must be evaluated
on a site-by-site basis in order to determine appropriate locations for and methods of releasing
runoff. Vegetated wetlands shall not be used for this purpose. Frequently, it may be possible to
pump water from the collection point at the downhill end of the site to an upslope vegetated
area. Pumping shall only augment the treatment system, not replace it, because of the
possibility of pump failure or runoff volume in excess of pump capacity.
All projects that are constructing permanent facilities for runoff quantity control should use the
rough-graded or final-graded permanent facilities for traps and ponds. This includes combined
facilities and infiltration facilities. When permanent facilities are used as temporary
sedimentation facilities, the surface area requirement of a sediment trap or pond must be met. If
the surface area requirements are larger than the surface area of the permanent facility, then
the trap or pond shall be enlarged to comply with the surface area requirement. The permanent
pond shall also be divided into two cells as required for sediment ponds.
Either a permanent control structure or the temporary control structure (described in BMP C241:
Temporary Sediment Pond) can be used. If a permanent control structure is used, it may be
advisable to partially restrict the lower orifice with gravel to increase residence time while still
allowing dewatering of the pond. A shut-off valve may be added to the control structure to allow
complete retention of stormwater in emergency situations. In this case, an emergency overflow
weir must be added.
A skimmer may be used for the sediment trap outlet if approved by the Local Permitting
Authority.
Design and Installation Specifications
See Figure II-4.2.16 Cross Section of Sediment Trap and Figure II-4.2.17 Sediment Trap
Outlet for details.
If permanent runoff control facilities are part of the project, they should be used for
sediment retention.
To determine the sediment trap geometry, first calculate the design surface area (SA) of
the trap, measured at the invert of the weir. Use the following equation:
SA = FS(Q2/Vs)
where
Q2 = Design inflow based on the peak discharge from the developed 2-year runoff event from
the contributing drainage area as computed in the hydrologic analysis. The 10-year peak flow
shall be used if the project size, expected timing and duration of construction, or downstream
conditions warrant a higher level of protection. If no hydrologic analysis is required, the Rational
Method may be used.
Vs = The settling velocity of the soil particle of interest. The 0.02 mm (medium silt) particle with
an assumed density of 2.65 g/cm3 has been selected as the particle of interest and has a
settling velocity (Vs) of 0.00096 ft/sec.
FS = A safety factor of 2 to account for non-ideal settling.
Therefore, the equation for computing surface area becomes:
SA = 2 x Q2/0.00096
or
2080 square feet per cfs of inflow
Note: Even if permanent facilities are used, they must still have a surface area that is at least as
large as that derived from the above formula. If they do not, the pond must be enlarged.
To aid in determining sediment depth, all sediment traps shall have a staff gauge with a
prominent mark 1-foot above the bottom of the trap.
Sediment traps may not be feasible on utility projects due to the limited work space or
the short-term nature of the work. Portable tanks may be used in place of sediment traps
for utility projects.
Maintenance Standards
Sediment shall be removed from the trap when it reaches 1-foot in depth.
Any damage to the pond embankments or slopes shall be repaired.
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limitation of liability, and disclaimer.
Figure II-4.2.16
Cross Section of Sediment Trap
Revised November 2015
NOT TO SCALE
3
H
:
1
V
M
a
x
.
3.5' - 5'
Flat Bottom 1.5' Min.
1' Min.
Surface area determined
at top of weir
34" - 1.5"
Washed gravel
Geotextile
2" - 4" Rock
Rip Rap
Discharge to
stabilized
conveyance,
outlet, or level
spreader
4' Min.
1' Min.
1' Min.
Overflow
Note: Trap may be formed by berm or by
partial or complete excavation.
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State of Washington
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limitation of liability, and disclaimer.
Figure II-4.2.17
Sediment Trap Outlet
Revised November 2015
NOT TO SCALE
6' Min.
1' Min. depth overflow spillway
Native soil or
compacted backfill
Geotextile
Min. 1' depth 2" - 4" rock
Min. 1' depth 3 4" - 1.5"
washed gravel
BMP C241: Temporary Sediment Pond
Purpose
Sediment ponds remove sediment from runoff originating from disturbed areas of the site.
Sediment ponds are typically designed to remove sediment no smaller than medium silt (0.02
mm). Consequently, they usually reduce turbidity only slightly.
Conditions of Use
Prior to leaving a construction site, stormwater runoff must pass through a sediment pond or
other appropriate sediment removal best management practice.
A sediment pond shall be used where the contributing drainage area is 3 acres or more. Ponds
must be used in conjunction with erosion control practices to reduce the amount of sediment
flowing into the basin.
Design and Installation Specifications
Sediment basins must be installed only on sites where failure of the structure would not
result in loss of life, damage to homes or buildings, or interruption of use or service of
public roads or utilities. Also, sediment traps and ponds are attractive to children and can
be very dangerous. Compliance with local ordinances regarding health and safety must
be addressed. If fencing of the pond is required, the type of fence and its location shall
be shown on the ESC plan.
Structures having a maximum storage capacity at the top of the dam of 10 acre-ft
(435,600 ft3) or more are subject to the Washington Dam Safety Regulations (Chapter
173-175 WAC).
See Figure II-4.2.18 Sediment Pond Plan View, Figure II-4.2.19 Sediment Pond Cross
Section, and Figure II-4.2.20 Sediment Pond Riser Detail for details.
If permanent runoff control facilities are part of the project, they should be used for
sediment retention. The surface area requirements of the sediment basin must be met.
This may require temporarily enlarging the permanent basin to comply with the surface
area requirements. The permanent control structure must be temporarily replaced with a
control structure that only allows water to leave the pond from the surface or by
pumping. The permanent control structure must be installed after the site is fully
stabilized. .
Use of infiltration facilities for sedimentation basins during construction tends to clog the
soils and reduce their capacity to infiltrate. If infiltration facilities are to be used, the sides
and bottom of the facility must only be rough excavated to a minimum of 2 feet above
final grade. Final grading of the infiltration facility shall occur only when all contributing
drainage areas are fully stabilized. The infiltration pretreatment facility should be fully
constructed and used with the sedimentation basin to help prevent clogging.
Determining Pond Geometry
Obtain the discharge from the hydrologic calculations of the peak flow for the 2-year
runoff event (Q2). The 10-year peak flow shall be used if the project size, expected
timing and duration of construction, or downstream conditions warrant a higher level of
protection. If no hydrologic analysis is required, the Rational Method may be used.
Determine the required surface area at the top of the riser pipe with the equation:
SA = 2 x Q2/0.00096
or
2080 square feet per cfs of inflow
See BMP C240: Sediment Trap for more information on the derivation of the surface
area calculation.
The basic geometry of the pond can now be determined using the following design
criteria:
Required surface area SA (from Step 2 above) at top of riser.
Minimum 3.5-foot depth from top of riser to bottom of pond.
Maximum 3H:1V interior side slopes and maximum 2H:1V exterior slopes. The interior
slopes can be increased to a maximum of 2H:1V if fencing is provided at or above the
maximum water surface.
One foot of freeboard between the top of the riser and the crest of the emergency
spillway.
Flat bottom.
Minimum 1-foot deep spillway.
Length-to-width ratio between 3:1 and 6:1.
Sizing of Discharge Mechanisms.
The outlet for the basin consists of a combination of principal and emergency spillways.
These outlets must pass the peak runoff expected from the contributing drainage area
for a 100-year storm. If, due to site conditions and basin geometry, a separate
emergency spill-way is not feasible, the principal spillway must pass the entire peak
runoff expected from the 100-year storm. However, an attempt to provide a separate
emergency spillway should always be made. The runoff calculations should be based on
the site conditions during construction. The flow through the dewatering orifice cannot be
utilized when calculating the 100-year storm elevation because of its potential to become
clogged; therefore, available spillway storage must begin at the principal spillway riser
crest.
The principal spillway designed by the procedures contained in this standard will result in
some reduction in the peak rate of runoff. However, the riser outlet design will not
adequately control the basin discharge to the predevelopment discharge limitations as
stated in I-2.5.7 Minimum Requirement #7: Flow Control. However, if the basin for a
permanent stormwater detention pond is used for a temporary sedimentation basin, the
control structure for the permanent pond can be used to maintain predevelopment
discharge limitations. The size of the basin, the expected life of the construction project,
the anticipated downstream effects and the anticipated weather conditions during
construction, should be considered to determine the need of additional discharge
control. See Figure II-4.2.21 Riser Inflow Curves for riser inflow curves.
DEPAR TM E N T OF
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State of Washington
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limitation of liability, and disclaimer.
Figure II-4.2.18
Sediment Pond Plan View
Revised November 2015
NOT TO SCALE
Note: Pond may be formed by berm or by partial or complete excavation
Inflow
Silt fence or
equivalent divider
Pond length
The pond length shall
be 3 to 6 times the
maximum pond width
Key divider into slope to
prevent flow around sides
Riser pipe
Emergency
overflow spillway
Discharge to stabilized
conveyance, outlet, or
level spreader
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State of Washington
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limitation of liability, and disclaimer.
Figure II-4.2.19
Sediment Pond Cross Section
Revised November 2015
NOT TO SCALE3H :
1V
Max
.3H : 1V Max.2H :
1V
Max
.
1.5'
1'
1' Min.
Wire-backed silt fence
staked haybales
wrapped with filter fabric,
or equivalent divider
Dewatering
orifice
Concrete base
(see riser detail)
Discharge to
stabilized
conveyance outlet
or level spreader
Dewatering device
(see riser detail)
Riser pipe
(principal spillway)
open at top with
trash rack
Crest of
emergency spillway 6' Min. width.
Embankment
compacted 95%
pervious materials
such as gravel or clean
sand shall not be used
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limitation of liability, and disclaimer.
Figure II-4.2.20
Sediment Pond Riser Detail
Revised November 2015
NOT TO SCALE
Tack weld
Dewatering orifice,
schedule 40 steel
stub min. diameter
per calculations
Provide adequate
strapping
Alternatively, metal
stakes and wire may be
used to prevent flotation
Polyethylene cap
Perforated
polyethylene drainage
tubing, diameter min.
2" larger than
dewatering orifice.
Tubing shall comply
with ASTM F667 and
AASHTO M294.
Watertight
coupling
Corrugated
metal riser
3.5' min.
18" min.
6" min.
Concrete base
2X riser dia. min.
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limitation of liability, and disclaimer.
Figure II-4.2.21
Riser Inflow Curves
Revised November 2015
Principal Spillway: Determine the required diameter for the principal spillway (riser pipe). The
diameter shall be the minimum necessary to pass the site’s 15-minute, 10-year flowrate. If using
the Western Washington Hydrology Model (WWHM), Version 2 or 3, design flow is the 10-year
(1 hour) flow for the developed (unmitigated) site, multiplied by a factor of 1.6. Use Figure II-
4.2.21 Riser Inflow Curves to determine this diameter (h = 1-foot). Note: A permanent control
structure may be used instead of a temporary riser.
Emergency Overflow Spillway: Determine the required size and design of the emergency
overflow spillway for the developed 100-year peak flow using the method contained in Volume
III.
Dewatering Orifice: Determine the size of the dewatering orifice(s) (minimum 1-inch diameter)
using a modified version of the discharge equation for a vertical orifice and a basic equation for
the area of a circular orifice. Determine the required area of the orifice with the following
equation:
where
Ao = orifice area (square feet)
AS = pond surface area (square feet)
h = head of water above orifice (height of riser in feet)
T = dewatering time (24 hours)
g = acceleration of gravity (32.2 feet/second2)
Convert the required surface area to the required diameter D of the orifice:
The vertical, perforated tubing connected to the dewatering orifice must be at least 2 inches
larger in diameter than the orifice to improve flow characteristics. The size and number of
perforations in the tubing should be large enough so that the tubing does not restrict flow. The
orifice should control the flow rate.
Additional Design Specifications
The pond shall be divided into two roughly equal volume cells by a permeable divider
that will reduce turbulence while allowing movement of water between cells. The divider
shall be at least one-half the height of the riser and a minimum of one foot below the top
of the riser. Wire-backed, 2- to 3-foot high, extra strength filter fabric supported by
treated 4"x4"s can be used as a divider. Alternatively, staked straw bales wrapped with
filter fabric (geotextile) may be used. If the pond is more than 6 feet deep, a different
mechanism must be proposed. A riprap embankment is one acceptable method of
separation for deeper ponds. Other designs that satisfy the intent of this provision are
allowed as long as the divider is permeable, structurally sound, and designed to prevent
erosion under or around the barrier.
To aid in determining sediment depth, one-foot intervals shall be prominently marked on
the riser.
If an embankment of more than 6 feet is proposed, the pond must comply with the
criteria contained in Volume III regarding dam safety for detention BMPs.
The most common structural failure of sedimentation basins is caused by piping. Piping
refers to two phenomena: (1) water seeping through fine-grained soil, eroding the soil
grain by grain and forming pipes or tunnels; and, (2) water under pressure flowing
upward through a granular soil with a head of sufficient magnitude to cause soil grains to
lose contact and capability for support.
The most critical construction sequences to prevent piping will be:
1. Tight connections between riser and barrel and other pipe connections.
2. Adequate anchoring of riser.
3. Proper soil compaction of the embankment and riser footing.
4. Proper construction of anti-seep devices.
Maintenance Standards
Sediment shall be removed from the pond when it reaches 1–foot in depth.
Any damage to the pond embankments or slopes shall be repaired.
P a g e | 34
Appendix D – Site Inspection Form
Construction Stormwater Site Inspection Form
Page 1
Project Name The New Elementary
School in Redmond
Ridge East
Permit # Inspection Date Time
Name of Certified Erosion Sediment Control Lead (CESCL) or qualified inspector if less than one acre
Print Name:
Approximate rainfall amount since the last inspection (in inches):
Approximate rainfall amount in the last 24 hours (in inches):
Current Weather Clear Cloudy Mist Rain Wind Fog
A. Type of inspection: Weekly Post Storm Event Other
B. Phase of Active Construction (check all that apply):
Pre Construction/installation of erosion/sediment
controls
Clearing/Demo/Grading Infrastructure/storm/roads
Concrete pours Vertical
Construction/buildings
Utilities
Offsite improvements Site temporary stabilized Final stabilization
C. Questions:
1. Were all areas of construction and discharge points inspected? Yes No
2. Did you observe the presence of suspended sediment, turbidity, discoloration, or oil sheen Yes No
3. Was a water quality sample taken during inspection? (refer to permit conditions S4 & S5) Yes No
4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or less?* Yes No
5. If yes to #4 was it reported to Ecology? Yes No
6. Is pH sampling required? pH range required is 6.5 to 8.5. Yes No
If answering yes to a discharge, describe the event. Include when, where, and why it happened; what action was taken,
and when.
*If answering yes to # 4 record NTU/Transparency with continual sampling daily until turbidity is 25 NTU or less/ transparency is 33
cm or greater.
Sampling Results: Date:
Parameter Method (circle one) Result Other/Note
NTU cm pH
Turbidity tube, meter, laboratory
pH Paper, kit, meter
Family First
Community Center
Construction Stormwater Site Inspection Form
Page 2
D. Check the observed status of all items. Provide “Action Required “details and dates.
Element # Inspection BMPs
Inspected
BMP needs
maintenance
BMP
failed
Action
required
(describe in
section F)
yes no n/a
1
Clearing
Limits
Before beginning land disturbing
activities are all clearing limits,
natural resource areas (streams,
wetlands, buffers, trees) protected
with barriers or similar BMPs? (high
visibility recommended)
2
Construction
Access
Construction access is stabilized
with quarry spalls or equivalent
BMP to prevent sediment from
being tracked onto roads?
Sediment tracked onto the road
way was cleaned thoroughly at the
end of the day or more frequent as
necessary.
3
Control Flow
Rates
Are flow control measures installed
to control stormwater volumes and
velocity during construction and do
they protect downstream
properties and waterways from
erosion?
If permanent infiltration ponds are
used for flow control during
construction, are they protected
from siltation?
4
Sediment
Controls
All perimeter sediment controls
(e.g. silt fence, wattles, compost
socks, berms, etc.) installed, and
maintained in accordance with the
Stormwater Pollution Prevention
Plan (SWPPP).
Sediment control BMPs (sediment
ponds, traps, filters etc.) have been
constructed and functional as the
first step of grading.
Stormwater runoff from disturbed
areas is directed to sediment
removal BMP.
5
Stabilize
Soils
Have exposed un-worked soils
been stabilized with effective BMP
to prevent erosion and sediment
deposition?
Construction Stormwater Site Inspection Form
Page 3
Element # Inspection BMPs
Inspected
BMP needs
maintenance
BMP
failed
Action
required
(describe in
section F)
yes no n/a
5
Stabilize Soils
Cont.
Are stockpiles stabilized from erosion,
protected with sediment trapping
measures and located away from drain
inlet, waterways, and drainage
channels?
Have soils been stabilized at the end of
the shift, before a holiday or weekend
if needed based on the weather
forecast?
6
Protect
Slopes
Has stormwater and ground water
been diverted away from slopes and
disturbed areas with interceptor dikes,
pipes and or swales?
Is off-site storm water managed
separately from stormwater generated
on the site?
Is excavated material placed on uphill
side of trenches consistent with safety
and space considerations?
Have check dams been placed at
regular intervals within constructed
channels that are cut down a slope?
7
Drain Inlets
Storm drain inlets made operable
during construction are protected.
Are existing storm drains within the
influence of the project protected?
8
Stabilize
Channel and
Outlets
Have all on-site conveyance channels
been designed, constructed and
stabilized to prevent erosion from
expected peak flows?
Is stabilization, including armoring
material, adequate to prevent erosion
of outlets, adjacent stream banks,
slopes and downstream conveyance
systems?
9
Control
Pollutants
Are waste materials and demolition
debris handled and disposed of to
prevent contamination of stormwater?
Has cover been provided for all
chemicals, liquid products, petroleum
products, and other material?
Has secondary containment been
provided capable of containing 110%
of the volume?
Were contaminated surfaces cleaned
immediately after a spill incident?
Were BMPs used to prevent
contamination of stormwater by a pH
modifying sources?
Construction Stormwater Site Inspection Form
Page 4
Element # Inspection BMPs
Inspected
BMP needs
maintenance
BMP
failed
Action
required
(describe in
section F)
yes no n/a
9
Cont.
Wheel wash wastewater is handled
and disposed of properly.
10
Control
Dewatering
Concrete washout in designated areas.
No washout or excess concrete on the
ground.
Dewatering has been done to an
approved source and in compliance
with the SWPPP.
Were there any clean non turbid
dewatering discharges?
11
Maintain
BMP
Are all temporary and permanent
erosion and sediment control BMPs
maintained to perform as intended?
12
Manage the
Project
Has the project been phased to the
maximum degree practicable?
Has regular inspection, monitoring and
maintenance been performed as
required by the permit?
Has the SWPPP been updated,
implemented and records maintained?
13
Protect LID
Is all Bioretention and Rain Garden
Facilities protected from
sedimentation with appropriate BMPs?
Is the Bioretention and Rain Garden
protected against over compaction of
construction equipment and foot
traffic to retain its infiltration
capabilities?
Permeable pavements are clean and
free of sediment and sediment laden-
water runoff. Muddy construction
equipment has not been on the base
material or pavement.
Have soiled permeable pavements
been cleaned of sediments and pass
infiltration test as required by
stormwater manual methodology?
Heavy equipment has been kept off
existing soils under LID facilities to
retain infiltration rate.
E. Check all areas that have been inspected.
All in place BMPs All disturbed soils All concrete wash out area All material storage areas
All discharge locations All equipment storage areas All construction entrances/exits
Construction Stormwater Site Inspection Form
Page 5
F. Elements checked “Action Required” (section D) describe corrective action to be taken. List the element number;
be specific on location and work needed. Document, initial, and date when the corrective action has been completed
and inspected.
Element
#
Description and Location Action Required Completion
Date
Initials
Attach additional page if needed
Sign the following certification:
“I certify that this report is true, accurate, and complete, to the best of my knowledge and belief”
Inspected by: (print) (Signature) Date:
Title/Qualification of Inspector:
P a g e | 35
Appendix E - Construction Stormwater General Permit (CSWGP)
3
4
.
–
–
5
S1.E.3.
1.
,,
b.
.
2.
.
,
.
b.
.
6
1..
. “surface
” may exist on a construction site as well as off site; for
2..
on
n
b.
.
3.Non .
.
b..
,.
d..
.
.
g..
h..
.
.
k..
.
7
,
–8.5 .
.
1..
2.up
.
3.40 C 122.2
4.,
unless
.
5.
.
6.
7., unless
8.
.
,
.
1.
.
2.p
CFR Subpart 122.
3.
4.on “Country” as defined in 18
§1151,
.
.
b.
.
.
.
.
5.
.
6.
.
1.
9
.
unless by
226 .
d.
Condition S9.C.4 (“demonstrably equivalent” BMPs), the
.
.
.
’
on ,
.
y.
.
,
v..
10
2.
.
.
1.A statement that “The applicant is seeking coverage under the Washington State
Department of Ecology’s Construction Stormwater NPDES and State Waste
”.
2..
3..
4.
,
.
5.
.
6.“
, ’s
,30
.
320.
, 98504
”
11
b.
.
4.
.
.
5.non
.
12
6.
Recalculate the rainfall erosivity “R” factor using the original start date and a
new projected ending date and, if the “R” factor is still under 5 and
b.
.
.
.
.
1.
.
2.
.
.
218
13
,
.
The Permittee’s
’
.
requirements of the Permittee’s Certified Erosion and Sediment Control Lead .
.
.
1.
.
.
by
.
b.
as soon as possible,
no
.
g .
2.,
.
.
.
14
3.
.
b.
4.
on .
.
5.
book.
b.
.
d.ions
.
.
g.
h.
.
15
statement: “I certify that this report is true, accurate, and complete to the best of
and belief.”
1 2
–
1 .
2
.
3
.
4
.
16
1.
b.
2.
b..
d.
.
.
.
g.
.
3.o
.
b.
.
d.
systems.
17
4.
.
b.
60 .
.
s s
5.
.
.
bodies on Washington State’s 303(d) list
.
.
–249 –
.
.
.
18
b.
If a discharge point’s turbidity is 250
Region’s Environmental Report Tracking System (ERTS) number
through Ecology’s Water Quality Permitting Portal [WQWebPortal] –
.
.
.
.
v.
25
19
,
50
–
.
bodies on Washington State’s 303(d) list
1.
8.5 .
2.
.
3.
.
4.
.
5.
.
6..
b.
8.5
2 .
2
.
7.
.
.
21
.
.
1..
2.
.
3..
4..
5..
6..
Permittee’s DMR.
,
22
Ecology’s Water Quality Permitting
.
.
.
by
.
1.
b.
d.
2.
23
b.
.
Permittee’s plans and records, the Permittee must either:
.
.
.
PERMIT FEES
.
.
.
216 110
TMDL
b
24
1.
and S4.C.3.b d
.
2.
6, or the date when the operator’s complete permit
unless
1.
2.
3. Provides
.
b.
.
1.
S4.C.2 and
.
25
2.
,
.
.
.
b.
.
3.
.
4.
.
1.
of pH 6.5 to 8.5 .
26
6
–
2.’
.
.
.
.
b.
27
.
.
d.
.
2.
y 1, 2016
before the date the operator’s complete permit application is received by Ecology,
. TMDLs completed after the operator’s complete permit
.
.
The Permittee’s SWPPP must meet the following objectives:
1.
2.
3.
1..
.
.
.
b..
13 13
.
28
d..
—
.
2.
.
b.
.
.
.
s to .
1.
2.
3..
n
226 230
29
4.
.
b.
–
13
13
.
1.
.
b.
.
2.
.
b.
.
d.
.
.
.
3.
30
b.
.
4.
mus
.
.
.
b..
.
.
.
d.
.
.
.
5.
.
31
b.
.
.
d.
West of the Cascade Mountains Crest
During the dry season (May 1 - September 30): 7 days
During the wet season (October 1 - April 30): 2 days
East of the Cascade Mountains Crest, except for Central Basin*
During the dry season (July 1 - September 30): 10 days
During the wet season (October 1 - June 30): 5 days
The Central Basin*, East of the Cascade Mountains Crest
During the dry season (July 1 - September 30): 30 days
During the wet season (October 1 - June 30): 15 days
g.
.
h..
6.
.
32
b.
.
.
.
.
1
.
.
.
soil areas should be modeled as "landscaped area.”
.
d.
7.
.
b.
.
8.
10
.
.
33
.
.
soil areas should be modeled as "landscaped area.”
.
b.
9.
.
d
b.
.
.
.
.
.
d.
.
.Follow manufacturers’ label
.
34
.
g.
.
h.
.
.
.
,
2 .
. Prior
10.
pond.
b.
.
. Note that “surface waters
tate” may exist on a construction si
.
.
.
.
Sa
.
35
v.
d.
11.
b.
wi
.
12.
b.–
.
.
u d onstruction SWPPP –
Conditions S3, S4 and S9.
13.
.
.
.
b.
.
.
36
.
d.
the manufacturer’s
–
The Permittee’s SWPPP must also include
.
1..
2..
3.
.
4..
5.
.
6.
7..
8.
.
9.
.
10.
11.
37
1.
2.
o
3.
.
–
98504 7696
.
38
.
.
1.
2.
3.
4.
.
.
1.
2.
.
.
“I certify under penalty of law, that this document and all attachments
.
39
.
possibility of fine and imprisonment for knowing violations.”
––
––
––
ON
.
.
.
, o
.
.
.
40
.
.
.
.
226
.
226
.
.
.
form (NOI) available on Ecology’s website.
98504 7696
41
AGE
The Director does not notify the current discharger and new discharger of the Director’s
.
.
.
.
.
42
.
separate and distinct offense, and in case of a continuing violation, every day’s continuan
– “Upset” means an exceptional incident in which there is unintentional and
.
,
.
.
43
p
.
.
.
.
.
.
A change in the construction plans and/or activity that affects the Permittee’s monitoring
.
.
.
44
.
220 216 070,
.
. .
.
.
permit coverage of an individual discharger is limited to the general permit’s
.
45
.
1.
.
2.
3.
. “Severe property damage” means substantial physical damage to
.
b.
.
4.
.
.
.
b.
.
.
d..
.
46
.
g..
h.
173 .
5.
.
.
b.
.
.
.
47
–
“
”
.
2016 ’
.
operator
Benchmark
.
.
.
.
.
Calendar
.
Calendar
.
Certified Erosion and Sediment Co
.
217, 95 576, 96
.
48
n.
.
.
.
W
.
.
S ground water.
.
. “”340 200.
,
,
1..
49
2..
3.
.
4..
5.
.
ground wat
.
.
operator
.
.
ground water
.
Erosion
.
.
synonymous with .
is an entity that meets the definition of “” in this permit and is either
50
.
0
law, 42 U.S.C., Sec.
.
.
.
.
226 200.
51
means a liquid’s measure of acidity or alkalinity. .
6.5 8.5.
.
.
.
.
W
.
W .
.
52
.
,. Ecology’s Construction
.
Responsible Corporate O
.
.
Sediment
Sedimentation .
Work
.
Significant Contributor of Pollutants
.
53
sodding.
.
.
Manual
.
.
.
.
. on.
substitute for the more permanent “.”
.
.
.
.
.
54
.
.
Transparency
.
.
as a “ube.”
.
. See definition of “” and
173 340 200.
Waste Load Allocation (WLA)means the portion of a receiving water’s loading capacity that
.
h
only Based Shaft Drilling
.
.
W W
.
55
–
EPA
NOT
TMDL
P a g e | 36
Appendix H – Engineering Calculations
COUGHLINPORTERLUNDEEN
A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION
Proposed Runoff Conditions for TESC - Temporary Sediment Pond
Total Site:Area (ac)
Pervious Area 0.000
Impervious Area 2.510
Total Area 2.510
MGS Flood 15-minute time step
10-Yr Developed Flow 1.46 cfs
Temporary Sediment Pond Sizing: Storage Volume per 2016 KCSWDM
Vr=S.A. x 3.5'Vr = Minimum Required Storage Volume
S.A. = Minimum allowable top surface area of pond
S.A. = (2Q10)/Vsed
Q = design peak flow rate
Vsed = 0.00096 Settling Velocity (0.00096 ft/sec)
Q=1.459 cfs INPUT (note that this is the 10-yr design peak flow rate in cfs)
S.A. = 3040 sf
Vr=10639 cf Volume Required
Project: Family First Community Center Designed by: CPS
Project No.: C180040-01 Client: COR Checked by: AJF Sheet 1 of 1
* the volume is based a minimum pond depth of 3.5' - this depth does not
include the minimum sediment storage volume or freeboard
801 Second Avenue ∙ Suite 900 ∙ Seattle, WA 98104 ∙ P: (206) 343-0460
Date: 2/17/20
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.46
Program License Number: 200610002
Project Simulation Performed on: 02/17/2020 7:03 PM
Report Generation Date: 02/17/2020 7:04 PM
—————————————————————————————————
Input File Name: 20-2-17 FFCC - TESC Calcs.fld
Project Name: FFCC - TESC Calcs
Analysis Title: Baker tank sizing
Comments: 2/17/20 TESC Calcs for permit
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 15
Extended Precipitation Time Series Selected
Climatic Region Number: 15
Full Period of Record Available used for Routing
Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961040 Puget East 40 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) 2.680 2.680
Area of Links that Include Precip/Evap (acres) 0.000 0.000
Total (acres) 2.680 2.680
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Forest 2.680
----------------------------------------------
Subbasin Total 2.680
MGSFLOOD REPORT FOR BAKER TANK SIZING CALCULATION
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Impervious 2.680
----------------------------------------------
Subbasin Total 2.680
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
Number of Links: 0
***********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: Subbasin 1 462.110
_____________________________________
Total: 462.110
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 0.000
_____________________________________
Total: 0.000
Total Predevelopment Recharge is Greater than Post Developed
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 2.925 ac-ft/year, Post Developed: 0.000 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
***********Compliance Point Results *************
Scenario Predeveloped Compliance Subbasin: Subbasin 1
Scenario Postdeveloped Compliance Subbasin: Subbasin 1
*** 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 5.711E-02 2-Year 0.999
5-Year 9.308E-02 5-Year 1.297
10-Year 0.125 10-Year 1.459
25-Year 0.159 25-Year 1.837
50-Year 0.203 50-Year 2.338
100-Year 0.220 100-Year 2.704
200-Year 0.342 200-Year 2.802
** 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%): 671.4% FAIL
Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): 3182.2% FAIL
Maximum Excursion from Q2 to Q50 (Must be less than 10%): 99999.0% FAIL
Percent Excursion from Q2 to Q50 (Must be less than 50%): 100.0% FAIL
-------------------------------------------------------------------------------------------------
FLOW DURATION DESIGN CRITERIA: FAIL
-------------------------------------------------------------------------------------------------
**** LID Duration Performance ****
Excursion at Predeveloped 8%Q2 (Must be Less Than 0%): 47.8% FAIL
Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): 671.4% FAIL
-------------------------------------------------------------------------------------------------
LID DURATION DESIGN CRITERIA: FAIL
-------------------------------------------------------------------------------------------------
FAMILY FIRST COMMUNITY CENTER
APPENDIX D – OPERATIONS AND MAINTENANCE MANUAL
www.modularwetlands.com
Maintenance Guidelines for
Modular Wetland System - Linear
Maintenance Summary
o Remove Trash from Screening Device – average maintenance interval is 6 to 12 months.
(5 minute average service time).
o Remove Sediment from Separation Chamber – average maintenance interval is 12 to 24 months.
(10 minute average service time).
o Replace Cartridge Filter Media – average maintenance interval 12 to 24 months.
(10-15 minute per cartridge average service time).
o Replace Drain Down Filter Media – average maintenance interval is 12 to 24 months.
(5 minute average service time).
o Trim Vegetation – average maintenance interval is 6 to 12 months.
(Service time varies).
System Diagram
Access to screening device, separation
chamber and cartridge filter
Access to drain
down filter
Pre-Treatment
Chamber
Biofiltration Chamber
Discharge
Chamber
Outflow
Pipe
Inflow Pipe
(optional)
www.modularwetlands.com
Maintenance Procedures
Screening Device
1. Remove grate or manhole cover to gain access to the screening device in the Pre-
Treatment Chamber. Vault type units do not have screening device. Maintenance
can be performed without entry.
2. Remove all pollutants collected by the screening device. Removal can be done
manually or with the use of a vacuum truck. The hose of the vacuum truck will not
damage the screening device.
3. Screening device can easily be removed from the Pre-Treatment Chamber to gain
access to separation chamber and media filters below. Replace grate or manhole
cover when completed.
Separation Chamber
1. Perform maintenance procedures of screening device listed above before
maintaining the separation chamber.
2. With a pressure washer spray down pollutants accumulated on walls and cartridge
filters.
3. Vacuum out Separation Chamber and remove all accumulated pollutants. Replace
screening device, grate or manhole cover when completed.
Cartridge Filters
1. Perform maintenance procedures on screening device and separation chamber
before maintaining cartridge filters.
2. Enter separation chamber.
3. Unscrew the two bolts holding the lid on each cartridge filter and remove lid.
4. Remove each of 4 to 8 media cages holding the media in place.
5. Spray down the cartridge filter to remove any accumulated pollutants.
6. Vacuum out old media and accumulated pollutants.
7. Reinstall media cages and fill with new media from manufacturer or outside
supplier. Manufacturer will provide specification of media and sources to purchase.
8. Replace the lid and tighten down bolts. Replace screening device, grate or
manhole cover when completed.
Drain Down Filter
1. Remove hatch or manhole cover over discharge chamber and enter chamber.
2. Unlock and lift drain down filter housing and remove old media block. Replace with
new media block. Lower drain down filter housing and lock into place.
3. Exit chamber and replace hatch or manhole cover.
www.modularwetlands.com
Maintenance Notes
1. Following maintenance and/or inspection, it is recommended the maintenance
operator prepare a maintenance/inspection record. The record should include any
maintenance activities performed, amount and description of debris collected, and
condition of the system and its various filter mechanisms.
2. The owner should keep maintenance/inspection record(s) for a minimum of five
years from the date of maintenance. These records should be made available to
the governing municipality for inspection upon request at any time.
3. Transport all debris, trash, organics and sediments to approved facility for disposal
in accordance with local and state requirements.
4. Entry into chambers may require confined space training based on state and local
regulations.
5. No fertilizer shall be used in the Biofiltration Chamber.
6. Irrigation should be provided as recommended by manufacturer and/or landscape
architect. Amount of irrigation required is dependent on plant species. Some plants
may require irrigation.
www.modularwetlands.com
Maintenance Procedure Illustration
Screening Device
The screening device is located directly
under the manhole or grate over the
Pre-Treatment Chamber. It’s mounted
directly underneath for easy access
and cleaning. Device can be cleaned by
hand or with a vacuum truck.
Separation Chamber
The separation chamber is located
directly beneath the screening device.
It can be quickly cleaned using a
vacuum truck or by hand. A pressure
washer is useful to assist in the
cleaning process.
www.modularwetlands.com
Cartridge Filters
The cartridge filters are located in the
Pre-Treatment chamber connected to
the wall adjacent to the biofiltration
chamber. The cartridges have
removable tops to access the
individual media filters. Once the
cartridge is open media can be
easily removed and replaced by hand
or a vacuum truck.
Drain Down Filter
The drain down filter is located in the
Discharge Chamber. The drain filter
unlocks from the wall mount and hinges
up. Remove filter block and replace with
new block.
www.modularwetlands.com
Trim Vegetation
Vegetation should be maintained in the
same manner as surrounding vegetation
and trimmed as needed. No fertilizer shall
be used on the plants. Irrigation
per the recommendation of the
manufacturer and or landscape
architect. Different types of vegetation
requires different amounts of
irrigation.
www.modularwetlands.com
Inspection Form
Modular Wetland System, Inc.
P. 760.433-7640
F. 760-433-3176
E. Info@modularwetlands.com
For Office Use Only
(city) (Zip Code)(Reviewed By)
Owner / Management Company
(Date)
Contact Phone ( )_
Inspector Name Date / / Time AM / PM
Weather Condition Additional Notes
Yes
Depth:
Yes No
Modular Wetland System Type (Curb, Grate or UG Vault):Size (22', 14' or etc.):
Other Inspection Items:
Storm Event in Last 72-hours? No Yes Type of Inspection Routine Follow Up Complaint Storm
Office personnel to complete section to
the left.
2972 San Luis Rey Road, Oceanside, CA 92058 P (760) 433-7640 F (760) 433-3176
Inspection Report
Modular Wetlands System
Is the filter insert (if applicable) at capacity and/or is there an accumulation of debris/trash on the shelf system?
Does the cartridge filter media need replacement in pre-treatment chamber and/or discharge chamber?
Any signs of improper functioning in the discharge chamber? Note issues in comments section.
Chamber:
Is the inlet/outlet pipe or drain down pipe damaged or otherwise not functioning properly?
Structural Integrity:
Working Condition:
Is there evidence of illicit discharge or excessive oil, grease, or other automobile fluids entering and clogging the
unit?
Is there standing water in inappropriate areas after a dry period?
Damage to pre-treatment access cover (manhole cover/grate) or cannot be opened using normal lifting
pressure?
Damage to discharge chamber access cover (manhole cover/grate) or cannot be opened using normal lifting
pressure?
Does the MWS unit show signs of structural deterioration (cracks in the wall, damage to frame)?
Project Name
Project Address
Inspection Checklist
CommentsNo
Does the depth of sediment/trash/debris suggest a blockage of the inflow pipe, bypass or cartridge filter? If yes,
specify which one in the comments section. Note depth of accumulation in in pre-treatment chamber.
Is there a septic or foul odor coming from inside the system?
Is there an accumulation of sediment/trash/debris in the wetland media (if applicable)?
Is it evident that the plants are alive and healthy (if applicable)? Please note Plant Information below.
Sediment / Silt / Clay
Trash / Bags / Bottles
Green Waste / Leaves / Foliage
Waste:Plant Information
No Cleaning Needed
Recommended Maintenance
Additional Notes:
Damage to Plants
Plant Replacement
Plant Trimming
Schedule Maintenance as Planned
Needs Immediate Maintenance
www.modularwetlands.com
Maintenance Report
Modular Wetland System, Inc.
P. 760.433-7640
F. 760-433-3176
E. Info@modularwetlands.com
For Office Use Only
(city) (Zip Code)(Reviewed By)
Owner / Management Company
(Date)
Contact Phone ( )_
Inspector Name Date / / Time AM / PM
Weather Condition Additional Notes
Site
Map #
Comments:
2972 San Luis Rey Road, Oceanside, CA 92058 P. 760.433.7640 F. 760.433.3176
Inlet and Outlet
Pipe Condition
Drain Down Pipe
Condition
Discharge Chamber
Condition
Drain Down Media
Condition
Plant Condition
Media Filter
Condition
Long:
MWS
Sedimentation
Basin
Total Debris
Accumulation
Condition of Media
25/50/75/100
(will be changed
@ 75%)
Operational Per
Manufactures'
Specifications
(If not, why?)
Lat:MWS
Catch Basins
GPS Coordinates
of Insert
Manufacturer /
Description / Sizing
Trash
Accumulation
Foliage
Accumulation
Sediment
Accumulation
Type of Inspection Routine Follow Up Complaint Storm Storm Event in Last 72-hours? No Yes
Office personnel to complete section to
the left.
Project Address
Project Name
Cleaning and Maintenance Report
Modular Wetlands System
An company
2
THE MOST ADVANCED NAME IN WATER MANAGEMENT SOLUTIONS TM
ECCENTRICHEADER
MANHOLEWITHOVERFLOWWEIR
STORMTECHISOLATOR ROW
OPTIONAL PRE-TREATMENT
OPTIONAL ACCESS STORMTECH CHAMBERS
)(
FAMILY FIRST COMMUNITY CENTER
APPENDIX E – FACILITIES SUMMARY AND DECLARATIONS OF
COVENANT
2016 KING COUNTY SURFACE WATER DESIGN MANUAL, REFERENCE D
4/24/2016
Page 1
STORMWATER FACILITY SUMMARY SHEET DPER Permit No.___________________
(provide one Stormwater Facility Summary Sheet per Natural Discharge Location)Date ___________________
OVERVIEW:NPDES Permit No.___________________
Project Name
Parcel No.____________________________
Project Location Retired Parcel No.____________________________
Downstream Drainage Basins:Project includes Landscape Management Plan?yes
Major Basin Name ______________________________________________(include copy with TIR as Appendix)no
Immediate Basin Name ______________________________________________
GENERAL FACILITY INFORMATION: Leachable Metals
Infiltration Impervious Surface Limit
Type # of Type # of Type # of facilities Flow Control BMPs
Ponds ______ Ponds ______ Ponds ______ Basic Clearing Limit
Vaults ______ Tanks ______ Vaults ______ Conservation Drainage Facility
Tanks ______ Trenches _____ Tanks ______ Flood Problem Landscape Management Plan
If no flow control facility, check one:
Project qualifies for KCSWDM Exemption (KCSWDM 1.2.3):
Basic Exemption (Applies to Commercial parcels only)Area % of Total
Redevelopment projects
Cost Exemption for Parcel Redevelopment projects
Direct Discharge Exemption
Other _____________________ Total impervious surface served by
Project qualifies for 0.1 cfs Exception per KCSWDM 1.2.3 flow control facility(ies) (sq ft)
Impervious surface served by flow
KCSWDM Adjustment No. ___________________control facility(ies) designed
1990 or later (sq ft)
approved KCSWDM Adjustment No. __________________ Impervious surface served by
Shared Facility Name/Location: _________________________ pervious surface absorption (sq ft)
No flow control required (other, provide justification): Impervious surface served by approved
____________________________________________________ water quality facility(ies) (sq ft)
Flow Control
Performance Std
Declarations of Covenant Recording No.
Water QualityDetention
TREATMENT SUMMARY FOR TOTAL IMPERVIOUS SURFACES
-----
Total Impervious Acreage (ac)
No flow control required per approved
Flow control provided in regional/shared facility per approved
PROVIDE FACILITY DETAILS AND FACILITY SKETCH FOR EACH FACILITY ON REVERSE. USE ADDITIONAL SHEETS AS NEEDED FOR ADDITIONAL FACILITIES
Impervious Surface Exemption for Transportation Total Acreage (ac)
Family First Community Center
12/05/2019
16022 116th Ave SE, Renton WA 98058
Cedar River
2
1
2823059034
2.51
Lower- Cedar River
--
--
TBD
TBD
TBD
1
2.03 80.9
1.19 47.4
0.84 33.5
2016 KING COUNTY SURFACE WATER DESIGN MANUAL, REFERENCE D
4/24/2016
Page 2
STORMWATER FACILITY SUMMARY SHEET DPER Permit No.___________________
(provide one Stormwater Facility Summary Sheet per Natural Discharge Location)
Project Name Downstream Drainage Basins:
Major Basin Name _______________________________
Project Location Immediate Basin Name ___________________________
FLOW CONTROL FACILITY:Basin:
Facility Name/Number _______________________________________ New Facility Project Impervious
Facility Location ____________________________________________ Existing Facility Acres Served ________
UIC? □ yes □ no UIC Site ID:% of Total Project Impervious
cu.ft.Volume Factor Acres Served ________
_____________ ac.ft.____________of Safety _______No. of Lots Served ________
Control Structure location: _______________________________________________
Type of Control Structure:No. of Orifices/Restrictions __________
Riser in vault Size of Orifice/Restriction (in.) No.1 ______ cu.ft.
Riser in Type II CB (numbered starting with lowest No.2 ______ ac.ft.
Weir in Type II CB orifice): No.3 ______
(inches in decimal format)No.4 ______
WATER QUALITY FACILITIES Design Information
Indicate no. of water quality facilities/BMPs for each type:Water Quality design flow (cfs)
_______Flow dispersion Water Quality treated volume (sandfilter) (cu.ft.)
_______Filter strip Water Quality storage volume (wetpool) (cu.ft.)
_______Biofiltration swale regular, wet or Landscape management plan Farm management plan
continuous inflow
_______Wetvault combined w/detention ______High flow bypass structure (e.g., flow-splitter catch basin)
_______Wetpond basic large combined w/detention ______Oil/water separator baffle coalescing plate
_______Pre-settling pond ______Storm filter
_______Stormwater wetland ______Pre-settling structure (Manufacturer:______________________)
_______Sand filter basic large Sand bed depth ______Catch basin inserts (Manufacturer:________________________)
regular linear vault (inches)______________Source controls _________________________________________
● Is facility lined? yes no If so, what marker is used above liner?_____________________________________________________
Facility Summary Sheet Sketch: All detention, infiltration and water quality facilities must include a detailed sketch (11"x17" reduced size plan sheets preferred).
Dam Safety Regulations (WA State Dept of
Ecology):
Reservoir Volume
above natural grade
Depth of Reservoir
above natural grade (ft)
Live Storage
Volume
Live Storage
Depth (ft)
Family First Community Center
16022 116th Ave SE, Renton WA 98058
Cedar River
Green River
Lower- Cedar River
0.86
43
STORMTECH SC-310 CHAMBERS
0.5
2
1.0
0.186
18,907
2016 KING COUNTY SURFACE WATER DESIGN MANUAL, REFERENCE D
4/24/2016
Page 2
STORMWATER FACILITY SUMMARY SHEET DPER Permit No.___________________
(provide one Stormwater Facility Summary Sheet per Natural Discharge Location)
Project Name Downstream Drainage Basins:
Major Basin Name _______________________________
Project Location Immediate Basin Name ___________________________
FLOW CONTROL FACILITY:Basin:
Facility Name/Number _______________________________________ New Facility Project Impervious
Facility Location ____________________________________________ Existing Facility Acres Served ________
UIC? □ yes □ no UIC Site ID:% of Total Project Impervious
cu.ft.Volume Factor Acres Served ________
_____________ ac.ft.____________of Safety _______No. of Lots Served ________
Control Structure location: _______________________________________________
Type of Control Structure:No. of Orifices/Restrictions __________
Riser in vault Size of Orifice/Restriction (in.) No.1 ______ cu.ft.
Riser in Type II CB (numbered starting with lowest No.2 ______ ac.ft.
Weir in Type II CB orifice): No.3 ______
(inches in decimal format)No.4 ______
WATER QUALITY FACILITIES Design Information
Indicate no. of water quality facilities/BMPs for each type:Water Quality design flow (cfs)
_______Flow dispersion Water Quality treated volume (sandfilter) (cu.ft.)
_______Filter strip Water Quality storage volume (wetpool) (cu.ft.)
_______Biofiltration swale regular, wet or Landscape management plan Farm management plan
continuous inflow
_______Wetvault combined w/detention ______High flow bypass structure (e.g., flow-splitter catch basin)
_______Wetpond basic large combined w/detention ______Oil/water separator baffle coalescing plate
_______Pre-settling pond ______Storm filter
_______Stormwater wetland ______Pre-settling structure (Manufacturer:______________________)
_______Sand filter basic large Sand bed depth ______Catch basin inserts (Manufacturer:________________________)
regular linear vault (inches)______________Source controls _________________________________________
● Is facility lined? yes no If so, what marker is used above liner?_____________________________________________________
Facility Summary Sheet Sketch: All detention, infiltration and water quality facilities must include a detailed sketch (11"x17" reduced size plan sheets preferred).
Dam Safety Regulations (WA State Dept of
Ecology):
Reservoir Volume
above natural grade
Depth of Reservoir
above natural grade (ft)
Live Storage
Volume
Live Storage
Depth (ft)
Family First Community Center
16022 116th Ave SE, Renton WA 98058
Cedar River
Green River
Lower- Cedar River
1.16
57
STORMTECH MC-3500 CHAMBERS
0.5
2
1.5
0.751
29,259
Modular Wetland
Figure -1A
Flow Control Facility
Scale 1"=20'
A
B
C
E
D
E.2
E.3
F 184 LF 8" SD @ 1.3%SD# 16 CB TYPE II -
RIM=455.27
IE=444.34 8"(IN)W
IE=444.34 8"(OUT)S
TC 455.88
BC 455.38
TC 457.78
BC 457.28
TC 455.89
BC 455.39
TC 455.46
BC 454.96
TC 455.60
BC 455.10TC 455.60
BC 455.10
NON-INFILTRATING
BIORETENTION CELL
SEE DETAIL
457.47
4 LF 6" 2.0%
CONNECT TO STORMTECH
CHAMBER SYSTEM
IE =452.92
17
C2.10
INSPECTION PORT
SEE DETAIL
STORMTECH
CHAMBER
OUTLET
IE=451.50
TC 455.46
BC 454.96
11
C2.10
TC 455.60
BC 455.10
TC 455.83
BC 455.33
C 456.99
C 456.49
S 456.41
83 LF 6" PERF
PIPE @ 0.0%
SDCO
RIM TO GRADE
IE = 453.00
ISOLATOR ROW
SEE DETAIL 3
C2.12
3:1 MAX
Detention Facility
Bioretention Cells
(non-infiltrating)
Figure -1B
Water Quality Facility
Scale 1"=20'
F
1110988.2765.554321
CONNECT TO STORMTECH
CHAMBER SYSTEM
4
4
L
F
8
"
SD
@
9
.
6%
C-3500 STORMTECH
HAMBERS DETENTION
YSTEM W/ 12" STONE BASE
60 CHAMBERS VOLUME
ROVIDED = 29,259 CF
EE SHEET C211 AND C212
OR DETAILS
MWS-L-4-6.33-V-UG
MODULAR WETLAND
SYSTEM FOR WATER
QUALITY TREATMENT
SEE DETAIL
.
CONNECT TO
STORMTECH
SYSTEM
3 LF 8"
SD @ 0.0%
14 LF 8"
SD @ 35.5%
SD# 21 CB TYPE II - 48"
RIM=457.20
IE=451.45 8"(BIDIRECTIONAL)W
IE=451.45 8"(OUT)SE
FLOW CONTROL
STRUCTURE
SEE DETAIL
SD# 47 CB TYPE I
RIM=457.84
IE=455.02 8"(OUT)N
SPILL CONTROL
STRUCTURE
8 LF 8" SD @ 50.6%
SD# 49 CB TYPE I
RIM=459.23
IE=454.76 8"(OUT)N
SPILL CONTROL STRUCTURE
8 LF 8" SD @ 42.3%
8" SD IE=446.77
WATER QUALITY
VAULT OUTLET
8" SD IE=447.27
WATER QUALITY
VAULT INLET
21 LF 6"
SD @ 2.0%
8
C2.10
460.71
INSPECTION PORT
SEE DETAIL
INSPECTION PORT
SEE DETAIL
FLUSH CURB
17 LF 6" SD @ 44.1%
19 LF 6" SD
@ 39.5%
35 LF 6" SD
@ 21.4%
11
C2.10
11
C2.10
TC 457.82
BC 457.32
TC 457.11
BC 456.61
TC 458.63
BC 458.13
TC 458.90
BC 458.40
TC 458.31
BC 457.81
TC 457.36
BC 456.86
TC 456.92
BC 456.42
TC 456.99
BC 456.49
TC 459.90
BC 459.40
TC 460.07
BC 459.57
TC 459.70
BC 459.20
460.50
FFE=460.50
460.50
TC 460.59
BC 460.09
TC 460.41
BC 459.91
TC 461.32
BC 460.82
TC 461.00
BC 460.50
TC 458.61
BC 458.11
1DS 1DS
GRADE BREAK
ISOLATOR ROW
SEE DETAIL 3
C2.11
18
C2.10
ISOLATOR ROW
SEE DETAIL 3
C2.12
54 LF 8" SD @ 7.5%
Water Treatment
Facility
Stormtech Chamber
Detention Facility
Page 1 of
3
Return Address:
City Clerk’s Office
City of Renton
1055 S Grady Way
Renton, WA 98057
DECLARATION OF COVENANT AND EASEMENT FOR INSPECTION
AND MAINTENANCE OF DRAINAGE FACILITIES AND ON-SITE BMPS
Grantor:
Grantee: City of Renton
Legal Description:
Assessor's Tax Parcel ID#:
IN CONSIDERATION of the approved City of Renton (check one of the following)
residential building permit, commercial building permit, clearing and grading permit,
subdivision permit, or short subdivision permit for application file No.
LUA/SWP_______________________ relating to the real property ("Property") described above, the
Grantor(s), the owner(s) in fee of that Property, hereby covenants(covenant) with the City of Renton, a
political subdivision of the state of Washington, that he/she(they) will observe, consent to, and abide by
the conditions and obligations set forth and described in Paragraphs 1 through 9 below with regard to the
Property, and hereby grants(grant) an easement as described in Paragraphs 2 and 3. Grantor(s) hereby
grants(grant), covenants(covenant), and agrees(agree) as follows:
1. The Grantor(s) or his/her(their) successors in interest and assigns ("Owners ") shall at their
own cost, operate, maintain, and keep in good repair, the Property's drainage facilities constructed as
required in the approved construction plans and specifications __________ on file with the City of
Renton and submitted to the City of Renton for the review and approval of permit(s)
_____________________________. The property's drainage facilities are shown and/or listed on Exhibit
A. The property’s drainage facilities shall be maintained in compliance with the operation and
maintenance schedule included and attached herein as Exhibit B. Drainage facilities include pipes,
channels, flow control facilities, water quality facilities, on-site best management practices (BMPs) and
other engineered structures designed to manage and/or treat stormwater on the Property. On-site BMPs
include dispersion and infiltration devices, bioretention, permeable pavements, rainwater harvesting
systems, tree retention credit, reduced impervious surface footprint, vegetated roofs and other measures
designed to mimic pre-developed hydrology and minimize stormwater runoff on the Property.
2. City of Renton shall have the right to ingress and egress over those portions of the Property
necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance
activities specified in this Declaration of Covenant and in accordance with the Renton Municipal Code.
City of Renton shall provide at least 30 days written notice to the Owners that entry on the Property is
City of Renton
See attached figure.
Page 2 of
3
planned for the inspection of drainage facilities. After the 30 days, the Owners shall allow the City of
Renton to enter for the sole purpose of inspecting drainage facilities. In lieu of inspection by the City, the
Owners may elect to engage a licensed civil engineer registered in the state of Washington who has
expertise in drainage to inspect the drainage facilities and provide a written report describing their
condition. If the engineer option is chosen, the Owners shall provide written notice to the City of Renton
within fifteen days of receiving the City’s notice of inspection. Within 30 days of giving this notice, the
Owners, or engineer on behalf of the Owners, shall provide the engineer’s report to the City of Renton. If
the report is not provided in a timely manner as specified above, the City of Renton may inspect the
drainage facilities without further notice.
3. If City of Renton determines from its inspection, or from an engineer’s report provided in
accordance with Paragraph 2, that maintenance, repair, restoration, and/or mitigation work is required to
be done to any of the drainage facilities, City of Renton shall notify the Owners of the specific
maintenance, repair, restoration, and/or mitigation work (Work) required pursuant to the Renton
Municipal Code. The City shall also set a reasonable deadline for the Owners to complete the Work, or to
provide an engineer’s report that verifies completion of the Work. After the deadline has passed, the
Owners shall allow the City access to re-inspect the drainage facilities unless an engineer’s report has
been provided verifying completion of the Work. If the Work is not completed within the time frame set
by the City, the City may initiate an enforcement action and/or perform the required maintenance, repair,
restoration, and/or mitigation work and hereby is given access to the Property for such purposes. Written
notice will be sent to the Owners stating the City’s intention to perform such work. This work will not
commence until at least seven (7) days after such notice is mailed. If, within the sole discretion of the
City, there exists an imminent or present danger, the seven (7) day notice period will be waived and
maintenance and/or repair work will begin immediately.
4. The Owners shall assume all responsibility for the cost of any maintenance, repair work, or
any measures taken by the City to address conditions as described in Paragraph 3. Such responsibility
shall include reimbursement to the City within thirty (30) days of the receipt of the invoice for any such
work performed. Overdue payments will require payment of interest at the maximum legal rate allowed
by RCW 19.52.020 (currently twelve percent (12%)). If the City initiates legal action to enforce this
agreement, the prevailing party in such action is entitled to recover reasonable litigation costs and
attorney’s fees.
5. The Owners are required to obtain written approval from City of Renton prior to filling,
piping, cutting, or removing vegetation (except in routine landscape maintenance) in open vegetated
stormwater facilities (such as swales, channels, ditches, ponds, etc.), or performing any alterations or
modifications to the drainage facilities referenced in this Declaration of Covenant.
6. Any notice or consent required to be given or otherwise provided for by the provisions of this
Agreement shall be effective upon personal delivery, or three (3) days after mailing by Certified Mail,
return receipt requested.
7. With regard to the matters addressed herein, this agreement constitutes the entire agreement
between the parties, and supersedes all prior discussions, negotiations, and all agreements whatsoever
whether oral or written.
8. This Declaration of Covenant is intended to protect the value and desirability and promote
efficient and effective management of surface water drainage of the real property described above, and
shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This
Page 3 of
3
Declaration of Covenant shall run with the land and be binding upon Grantor(s), and Grantor's(s')
successors in interest, and assigns.
9. This Declaration of Covenant may be terminated by execution of a written agreement by the
Owners and the City that is recorded by King County in its real property records.
IN WITNESS WHEREOF, this Declaration of Covenant for the Inspection and Maintenance of
Drainage Facilities is executed this _____ day of ____________________, 20_____.
GRANTOR, owner of the Property
GRANTOR, owner of the Property
STATE OF WASHINGTON )
COUNTY OF KING )ss.
On this day personally appeared before me:
, to me known to be the individual(s) described in
and who executed the within and foregoing instrument and acknowledged that they signed the same as
their free and voluntary act and deed, for the uses and purposes therein stated.
Given under my hand and official seal this _____ day of ____________________, 20_____.
Printed name
Notary Public in and for the State of Washington,
residing at
My appointment expires
Legal Description
(LEGAL DESCRIPTION PER R1)
THE SOUTH 800 FEET OF THE NORTH 830 FEET OF THE WEST
816.75 FEET OF THE NORTHWEST QUARTER OF SECTION 28,
TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., IN KING COUNTY,
WASHINGTON; EXCEPT THE WEST 30 FEET THEREOF
CONVEYED TO KING COUNTY FOR 116TH AVE SE BY DEED
RECORDED UNDER RECORDING NO. 5091695; TOGETHER
WITH THAT PORTION OF THE SOUTH 800 FEET OF THE
NORTH 830 FEET OF THE NORTHWEST QUARTER OF
SECTION 28, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., IN
KING COUNTY, WASHINGTON, LYING WESTERLY OF THE PLAT
OF CASCADE HILLS NO. 2, ACCORDING TO THE PLAT
THEREOF RECORDED IN VOLUME 61 OF PLATS, PAGES 13
AND 14, IN KING COUNTY WASHINGTON; EXCEPT THE WEST
816.75 FEET THEREOF.
Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200Date Prepared: Name:PE Registration No:Firm Name:Firm Address:Phone No.Email Address:Project Name: Project Owner:CED Plan # (LUA):Phone:CED Permit # (U):Address: Site Address:Street Intersection:Addt'l Project Owner:Parcel #(s):Phone:Address: Clearing and grading greater than or equal to 5,000 board feet of timber? Yes/No:NOWater Service Provided by:If Yes, Provide Forest Practice Permit #:Sewer Service Provided by: AddressAbbreviated Legal Description:Northwest Quarter of Section 28, Township 23 N, Range 5 E, W.M., in King County, WA. Recording No. 5091695. According to the Plat Thereof Recorded in Volume 61 of Plats, Pages 13 and 14, in King County WA.City, State, Zip16022 116th Ave SE, Renton WA 98058AddressAdditional Project Owner116th Ave SE & SE 163rd StTBDPhone12/5/2019Prepared by:FOR APPROVALProject Phase 1AaronF@cplinc.comAaron FjelstadPE Registration No.Coughling Porter Lundeen801 2nd Ave Suite 900, Seattle WA 98104(206)343-0460SITE IMPROVEMENT BOND QUANTITY WORKSHEETPROJECT INFORMATIONSOOS CREEK WATER & SEWERSOOS CREEK WATER & SEWER1 Select the current project status/phase from the following options: For Approval - Preliminary Data Enclosed, pending approval from the City; For Construction - Estimated Data Enclosed, Plans have been approved for contruction by the City; Project Closeout - Final Costs and Quantities Enclosed for Project Close-out SubmittalPhoneEngineer Stamp Required (all cost estimates must have original wet stamp and signature)Clearing and GradingUtility ProvidersN/AProject Location and DescriptionProject Owner InformationFamily First Community CenterCity, State, Zip2823059034City of RentonTBDPage 2 of 14Ref 8-H Bond Quantity WorksheetSECTION I PROJECT INFORMATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDUnitReference #PriceUnitQuantity CostBackfill & compaction-embankmentESC-16.50$ CY Check dams, 4" minus rockESC-2SWDM 5.4.6.380.00$ Each161,280.00Catch Basin ProtectionESC-335.50$ Each8284.00Crushed surfacing 1 1/4" minusESC-4WSDOT 9-03.9(3)95.00$ CY DitchingESC-59.00$ CY Excavation-bulkESC-62.00$ CY Fence, siltESC-7SWDM 5.4.3.11.50$ LF Fence, Temporary (NGPE)ESC-81.50$ LF Geotextile FabricESC-92.50$ SY Hay Bale Silt TrapESC-100.50$ Each HydroseedingESC-11SWDM 5.4.2.40.80$ SY Interceptor Swale / DikeESC-121.00$ LF819819.00Jute MeshESC-13SWDM 5.4.2.23.50$ SY Level SpreaderESC-141.75$ LF Mulch, by hand, straw, 3" deepESC-15SWDM 5.4.2.12.50$ SY Mulch, by machine, straw, 2" deepESC-16SWDM 5.4.2.12.00$ SY Piping, temporary, CPP, 6"ESC-1712.00$ LF Piping, temporary, CPP, 8"ESC-1814.00$ LF Piping, temporary, CPP, 12"ESC-1918.00$ LF Plastic covering, 6mm thick, sandbaggedESC-20SWDM 5.4.2.34.00$ SY Rip Rap, machine placed; slopesESC-21WSDOT 9-13.1(2)45.00$ CY Rock Construction Entrance, 50'x15'x1'ESC-22SWDM 5.4.4.11,800.00$ Each Rock Construction Entrance, 100'x15'x1'ESC-23SWDM 5.4.4.13,200.00$ Each Sediment pond riser assemblyESC-24SWDM 5.4.5.22,200.00$ Each12,200.00Sediment trap, 5' high berm ESC-25SWDM 5.4.5.119.00$ LF Sed. trap, 5' high, riprapped spillway berm section ESC-26SWDM 5.4.5.170.00$ LF Seeding, by handESC-27SWDM 5.4.2.41.00$ SY Sodding, 1" deep, level groundESC-28SWDM 5.4.2.58.00$ SY Sodding, 1" deep, sloped groundESC-29SWDM 5.4.2.510.00$ SY TESC SupervisorESC-30110.00$ HR Water truck, dust controlESC-31SWDM 5.4.7140.00$ HR UnitReference #PriceUnitQuantity Cost EROSION/SEDIMENT SUBTOTAL:4,583.00SALES TAX @ 10%458.30EROSION/SEDIMENT TOTAL:5,041.30(A)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR EROSION & SEDIMENT CONTROLDescription No.(A)WRITE-IN-ITEMS Page 3 of 14Ref 8-H Bond Quantity WorksheetSECTION II.a EROSION_CONTROLUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostGENERAL ITEMS Backfill & Compaction- embankmentGI-16.00$ CYBackfill & Compaction- trenchGI-29.00$ CYClear/Remove Brush, by hand (SY)GI-31.00$ SYBollards - fixedGI-4240.74$ EachBollards - removableGI-5452.34$ EachClearing/Grubbing/Tree RemovalGI-610,000.00$ Acre2.5125,100.00Excavation - bulkGI-72.00$ CYExcavation - TrenchGI-85.00$ CYFencing, cedar, 6' highGI-920.00$ LFFencing, chain link, 4'GI-1038.31$ LFFencing, chain link, vinyl coated, 6' highGI-1120.00$ LF170534,100.00Fencing, chain link, gate, vinyl coated, 20' GI-121,400.00$ EachFill & compact - common barrowGI-1325.00$ CYFill & compact - gravel baseGI-1427.00$ CYFill & compact - screened topsoilGI-1539.00$ CYGabion, 12" deep, stone filled mesh GI-1665.00$ SYGabion, 18" deep, stone filled mesh GI-1790.00$ SYGabion, 36" deep, stone filled meshGI-18150.00$ SYGrading, fine, by handGI-192.50$ SYGrading, fine, with graderGI-202.00$ SYMonuments, 3' LongGI-21250.00$ EachSensitive Areas SignGI-227.00$ EachSodding, 1" deep, sloped groundGI-238.00$ SYSurveying, line & gradeGI-24850.00$ DaySurveying, lot location/linesGI-251,800.00$ AcreTopsoil Type A (imported)GI-2628.50$ CYTraffic control crew ( 2 flaggers )GI-27120.00$ HRTrail, 4" chipped woodGI-288.00$ SYTrail, 4" crushed cinderGI-299.00$ SYTrail, 4" top courseGI-3012.00$ SYConduit, 2"GI-315.00$ LFWall, retaining, concreteGI-3255.00$ SFWall, rockeryGI-3315.00$ SFSUBTOTAL THIS PAGE:59,200.00(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)Page 4 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)ROAD IMPROVEMENT/PAVEMENT/SURFACINGAC Grinding, 4' wide machine < 1000syRI-130.00$ SYAC Grinding, 4' wide machine 1000-2000syRI-216.00$ SYAC Grinding, 4' wide machine > 2000syRI-310.00$ SYAC Removal/DisposalRI-435.00$ SY238183,335.00Barricade, Type III ( Permanent )RI-556.00$ LFGuard RailRI-630.00$ LFCurb & Gutter, rolledRI-717.00$ LF2043,468.00Curb & Gutter, verticalRI-812.50$ LF278634,825.00Curb and Gutter, demolition and disposalRI-918.00$ LF105118,918.00Curb, extruded asphaltRI-105.50$ LFCurb, extruded concreteRI-117.00$ LFSawcut, asphalt, 3" depthRI-121.85$ LF7481,383.80Sawcut, concrete, per 1" depthRI-133.00$ LFSealant, asphaltRI-142.00$ LFShoulder, gravel, 4" thickRI-1515.00$ SYSidewalk, 4" thickRI-1638.00$ SY157559,850.00Sidewalk, 4" thick, demolition and disposalRI-1732.00$ SY81225,984.00Sidewalk, 5" thickRI-1841.00$ SYSidewalk, 5" thick, demolition and disposalRI-1940.00$ SYSign, Handicap RI-2085.00$ EachStriping, per stallRI-217.00$ Each108756.00Striping, thermoplastic, ( for crosswalk )RI-223.00$ SF4401,320.00Striping, 4" reflectorized lineRI-230.50$ LFAdditional 2.5" Crushed SurfacingRI-243.60$ SYHMA 1/2" Overlay 1.5" RI-2514.00$ SYHMA 1/2" Overlay 2"RI-2618.00$ SYHMA Road, 2", 4" rock, First 2500 SYRI-2728.00$ SYHMA Road, 2", 4" rock, Qty. over 2500SYRI-2821.00$ SYHMA Road, 4", 6" rock, First 2500 SYRI-2945.00$ SYHMA Road, 4", 6" rock, Qty. over 2500 SYRI-3037.00$ SYHMA Road, 4", 4.5" ATBRI-3138.00$ SYGravel Road, 4" rock, First 2500 SYRI-3215.00$ SYGravel Road, 4" rock, Qty. over 2500 SYRI-3310.00$ SYThickened EdgeRI-348.60$ LFSUBTOTAL THIS PAGE:229,839.80(B)(C)(D)(E)Page 5 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)PARKING LOT SURFACINGNo.2" AC, 2" top course rock & 4" borrowPL-121.00$ SY5748120,708.002" AC, 1.5" top course & 2.5" base coursePL-228.00$ SY4" select borrowPL-35.00$ SY1.5" top course rock & 2.5" base coursePL-414.00$ SYSUBTOTAL PARKING LOT SURFACING:120,708.00(B)(C)(D)(E)LANDSCAPING & VEGETATIONNo.Street TreesLA-1Median LandscapingLA-2Right-of-Way LandscapingLA-3Wetland LandscapingLA-4SUBTOTAL LANDSCAPING & VEGETATION:(B)(C)(D)(E)TRAFFIC & LIGHTINGNo.SignsTR-1Street Light System ( # of Poles)TR-2Traffic SignalTR-3Traffic Signal ModificationTR-4SUBTOTAL TRAFFIC & LIGHTING:(B)(C)(D)(E)WRITE-IN-ITEMSSUBTOTAL WRITE-IN ITEMS:STREET AND SITE IMPROVEMENTS SUBTOTAL:409,747.80SALES TAX @ 10%40,974.78STREET AND SITE IMPROVEMENTS TOTAL:450,722.58(B)(C)(D)(E)Page 6 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostDRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/DD-126.00$ SY* (CBs include frame and lid)BeehiveD-290.00$ Each190.00Through-curb Inlet FrameworkD-3400.00$ EachCB Type ID-41,500.00$ Each812,000.00CB Type ILD-51,750.00$ EachCB Type II, 48" diameterD-62,300.00$ Each511,500.00 for additional depth over 4' D-7480.00$ FTCB Type II, 54" diameterD-82,500.00$ Each for additional depth over 4'D-9495.00$ FTCB Type II, 60" diameterD-102,800.00$ Each25,600.00 for additional depth over 4'D-11600.00$ FTCB Type II, 72" diameterD-126,000.00$ Each for additional depth over 4'D-13850.00$ FTCB Type II, 96" diameterD-1414,000.00$ Each for additional depth over 4'D-15925.00$ FTTrash Rack, 12"D-16350.00$ EachTrash Rack, 15"D-17410.00$ EachTrash Rack, 18"D-18480.00$ EachTrash Rack, 21"D-19550.00$ EachCleanout, PVC, 4"D-20150.00$ EachCleanout, PVC, 6"D-21170.00$ Each1170.00Cleanout, PVC, 8"D-22200.00$ EachCulvert, PVC, 4" D-2310.00$ LFCulvert, PVC, 6" D-2413.00$ LFCulvert, PVC, 8" D-2515.00$ LFCulvert, PVC, 12" D-2623.00$ LFCulvert, PVC, 15" D-2735.00$ LFCulvert, PVC, 18" D-2841.00$ LFCulvert, PVC, 24"D-2956.00$ LFCulvert, PVC, 30" D-3078.00$ LFCulvert, PVC, 36" D-31130.00$ LFCulvert, CMP, 8"D-3219.00$ LFCulvert, CMP, 12"D-3329.00$ LFSUBTOTAL THIS PAGE:29,360.00(B)(C)(D)(E)Quantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESPage 7 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, CMP, 15"D-3435.00$ LFCulvert, CMP, 18"D-3541.00$ LFCulvert, CMP, 24"D-3656.00$ LFCulvert, CMP, 30"D-3778.00$ LFCulvert, CMP, 36"D-38130.00$ LFCulvert, CMP, 48"D-39190.00$ LFCulvert, CMP, 60"D-40270.00$ LFCulvert, CMP, 72"D-41350.00$ LFCulvert, Concrete, 8"D-4242.00$ LFCulvert, Concrete, 12"D-4348.00$ LFCulvert, Concrete, 15"D-4478.00$ LFCulvert, Concrete, 18"D-4548.00$ LFCulvert, Concrete, 24"D-4678.00$ LFCulvert, Concrete, 30"D-47125.00$ LFCulvert, Concrete, 36"D-48150.00$ LFCulvert, Concrete, 42"D-49175.00$ LFCulvert, Concrete, 48"D-50205.00$ LFCulvert, CPE Triple Wall, 6" D-5114.00$ LFCulvert, CPE Triple Wall, 8" D-5216.00$ LFCulvert, CPE Triple Wall, 12" D-5324.00$ LFCulvert, CPE Triple Wall, 15" D-5435.00$ LFCulvert, CPE Triple Wall, 18" D-5541.00$ LFCulvert, CPE Triple Wall, 24" D-5656.00$ LFCulvert, CPE Triple Wall, 30" D-5778.00$ LFCulvert, CPE Triple Wall, 36" D-58130.00$ LFCulvert, LCPE, 6"D-5960.00$ LFCulvert, LCPE, 8"D-6072.00$ LFCulvert, LCPE, 12"D-6184.00$ LFCulvert, LCPE, 15"D-6296.00$ LFCulvert, LCPE, 18"D-63108.00$ LFCulvert, LCPE, 24"D-64120.00$ LFCulvert, LCPE, 30"D-65132.00$ LFCulvert, LCPE, 36"D-66144.00$ LFCulvert, LCPE, 48"D-67156.00$ LFCulvert, LCPE, 54"D-68168.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 8 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, LCPE, 60"D-69180.00$ LFCulvert, LCPE, 72"D-70192.00$ LFCulvert, HDPE, 6"D-7142.00$ LF1506,300.00Culvert, HDPE, 8"D-7242.00$ LF120150,442.00Culvert, HDPE, 12"D-7374.00$ LFCulvert, HDPE, 15"D-74106.00$ LFCulvert, HDPE, 18"D-75138.00$ LFCulvert, HDPE, 24"D-76221.00$ LFCulvert, HDPE, 30"D-77276.00$ LFCulvert, HDPE, 36"D-78331.00$ LFCulvert, HDPE, 48"D-79386.00$ LFCulvert, HDPE, 54"D-80441.00$ LFCulvert, HDPE, 60"D-81496.00$ LFCulvert, HDPE, 72"D-82551.00$ LFPipe, Polypropylene, 6"D-8384.00$ LFPipe, Polypropylene, 8"D-8489.00$ LFPipe, Polypropylene, 12"D-8595.00$ LFPipe, Polypropylene, 15"D-86100.00$ LFPipe, Polypropylene, 18"D-87106.00$ LFPipe, Polypropylene, 24"D-88111.00$ LFPipe, Polypropylene, 30"D-89119.00$ LFPipe, Polypropylene, 36"D-90154.00$ LFPipe, Polypropylene, 48"D-91226.00$ LFPipe, Polypropylene, 54"D-92332.00$ LFPipe, Polypropylene, 60"D-93439.00$ LFPipe, Polypropylene, 72"D-94545.00$ LFCulvert, DI, 6"D-9561.00$ LFCulvert, DI, 8"D-9684.00$ LFCulvert, DI, 12"D-97106.00$ LFCulvert, DI, 15"D-98129.00$ LFCulvert, DI, 18"D-99152.00$ LFCulvert, DI, 24"D-100175.00$ LFCulvert, DI, 30"D-101198.00$ LFCulvert, DI, 36"D-102220.00$ LFCulvert, DI, 48"D-103243.00$ LFCulvert, DI, 54"D-104266.00$ LFCulvert, DI, 60"D-105289.00$ LFCulvert, DI, 72"D-106311.00$ LFSUBTOTAL THIS PAGE:56,742.00(B)(C)(D)(E)Page 9 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESSpecialty Drainage ItemsDitching SD-19.50$ CYFlow Dispersal Trench (1,436 base+)SD-328.00$ LF French Drain (3' depth)SD-426.00$ LFGeotextile, laid in trench, polypropyleneSD-53.00$ SYMid-tank Access Riser, 48" dia, 6' deepSD-62,000.00$ EachPond Overflow SpillwaySD-716.00$ SYRestrictor/Oil Separator, 12"SD-81,150.00$ EachRestrictor/Oil Separator, 15"SD-91,350.00$ EachRestrictor/Oil Separator, 18"SD-101,700.00$ EachRiprap, placedSD-1142.00$ CYTank End Reducer (36" diameter)SD-121,200.00$ EachInfiltration pond testingSD-13125.00$ HRPermeable PavementSD-14Permeable Concrete SidewalkSD-15Culvert, Box __ ft x __ ftSD-16SUBTOTAL SPECIALTY DRAINAGE ITEMS:(B)(C)(D)(E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention PondSF-1Each Detention TankSF-2Each Detention VaultSF-3Each Infiltration PondSF-4Each Infiltration TankSF-5Each Infiltration VaultSF-6Each Infiltration TrenchesSF-7Each Basic Biofiltration SwaleSF-8Each Wet Biofiltration SwaleSF-9Each WetpondSF-10Each WetvaultSF-11Each Sand FilterSF-12Each Sand Filter VaultSF-13Each Linear Sand FilterSF-14Each Proprietary FacilitySF-15Each Bioretention FacilitySF-16Each SUBTOTAL STORMWATER FACILITIES:(B)(C)(D)(E)Page 10 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESWRITE-IN-ITEMS (INCLUDE ON-SITE BMPs)WI-1WI-2WI-3WI-4WI-5WI-6WI-7WI-8WI-9WI-10WI-11WI-12WI-13WI-14WI-15SUBTOTAL WRITE-IN ITEMS:DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:86,102.00SALES TAX @ 10%8,610.20DRAINAGE AND STORMWATER FACILITIES TOTAL:94,712.20(B) (C) (D) (E)Page 11 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostConnection to Existing WatermainW-12,000.00$ EachDuctile Iron Watermain, CL 52, 4 Inch DiameterW-250.00$ LFDuctile Iron Watermain, CL 52, 6 Inch DiameterW-356.00$ LFDuctile Iron Watermain, CL 52, 8 Inch DiameterW-460.00$ LFDuctile Iron Watermain, CL 52, 10 Inch DiameterW-570.00$ LFDuctile Iron Watermain, CL 52, 12 Inch DiameterW-680.00$ LFGate Valve, 4 inch DiameterW-7500.00$ EachGate Valve, 6 inch DiameterW-8700.00$ EachGate Valve, 8 Inch DiameterW-9800.00$ EachGate Valve, 10 Inch DiameterW-101,000.00$ EachGate Valve, 12 Inch DiameterW-111,200.00$ EachFire Hydrant AssemblyW-124,000.00$ EachPermanent Blow-Off AssemblyW-131,800.00$ EachAir-Vac Assembly, 2-Inch DiameterW-142,000.00$ EachAir-Vac Assembly, 1-Inch DiameterW-151,500.00$ EachCompound Meter Assembly 3-inch DiameterW-168,000.00$ EachCompound Meter Assembly 4-inch DiameterW-179,000.00$ EachCompound Meter Assembly 6-inch DiameterW-1810,000.00$ EachPressure Reducing Valve Station 8-inch to 10-inchW-1920,000.00$ EachWATER SUBTOTAL:SALES TAX @ 10%WATER TOTAL:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR WATERQuantity Remaining (Bond Reduction) (B)(C)Page 12 of 14Ref 8-H Bond Quantity WorksheetSECTION II.d WATERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
CED Permit #:TBDExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostClean OutsSS-11,000.00$ EachGrease Interceptor, 500 gallonSS-28,000.00$ EachGrease Interceptor, 1000 gallonSS-310,000.00$ EachGrease Interceptor, 1500 gallonSS-415,000.00$ EachSide Sewer Pipe, PVC. 4 Inch DiameterSS-580.00$ LFSide Sewer Pipe, PVC. 6 Inch DiameterSS-695.00$ LFSewer Pipe, PVC, 8 inch DiameterSS-7105.00$ LFSewer Pipe, PVC, 12 Inch DiameterSS-8120.00$ LFSewer Pipe, DI, 8 inch DiameterSS-9115.00$ LFSewer Pipe, DI, 12 Inch DiameterSS-10130.00$ LFManhole, 48 Inch DiameterSS-116,000.00$ EachManhole, 54 Inch DiameterSS-136,500.00$ EachManhole, 60 Inch DiameterSS-157,500.00$ EachManhole, 72 Inch DiameterSS-178,500.00$ EachManhole, 96 Inch DiameterSS-1914,000.00$ EachPipe, C-900, 12 Inch DiameterSS-21180.00$ LFOutside DropSS-241,500.00$ LSInside DropSS-251,000.00$ LSSewer Pipe, PVC, ____ Inch DiameterSS-26Lift Station (Entire System)SS-27LSSANITARY SEWER SUBTOTAL:SALES TAX @ 10%SANITARY SEWER TOTAL:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR SANITARY SEWERQuantity Remaining (Bond Reduction) (B)(C)Page 13 of 14Ref 8-H Bond Quantity WorksheetSECTION II.e SANITARY SEWERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200Date:Name:Project Name: PE Registration No:CED Plan # (LUA):Firm Name:CED Permit # (U):Firm Address:Site Address:Phone No.Parcel #(s):Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a)Existing Right-of-Way Improvements Subtotal (b)(b)-$ Future Public Improvements Subtotal(c)-$ Stormwater & Drainage Facilities (Public & Private) Subtotal(d)(d)94,712.20$ (e)(f)Site RestorationCivil Construction PermitMaintenance Bond18,942.44$ Bond Reduction2Construction Permit Bond Amount 3Minimum Bond Amount is $10,000.001 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering.2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% willcover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering.* Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton.** Note: All prices include labor, equipment, materials, overhead and profit. EST1((b) + (c) + (d)) x 20%-$ MAINTENANCE BOND */**(after final acceptance of construction)5,041.30$ -$ 94,712.20$ 5,041.30$ -$ 94,712.20$ -$ 99,753.50$ P (a) x 100%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS12/5/2019Aaron FjelstadPE Registration No.Coughling Porter LundeenR((b x 150%) + (d x 100%))S(e) x 150% + (f) x 100%Bond Reduction: Existing Right-of-Way Improvements (Quantity Remaining)2Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2T(P +R - S)Prepared by:Project InformationCONSTRUCTION BOND AMOUNT */**(prior to permit issuance)(206)343-0460AaronF@cplinc.comFamily First Community CenterTBD16022 116th Ave SE, Renton WA 980582823059034FOR APPROVALTBD801 2nd Ave Suite 900, Seattle WA 98104Page 14 of 14Ref 8-H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/5/2019
Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011
Phone 425.415.0551 ♦ Fax 425.415.0311 www.riley-group.com
GEOTECHNICAL ENGINEERING REPORT
PREPARED BY:
THE RILEY GROUP, INC.
17522 BOTHELL WAY NORTHEAST
BOTHELL, WASHINGTON 98011
PREPARED FOR:
MS. KELLY BEYMER
ADMINISTRATOR OF COMMUNITY SERVICE DEPARTMENT
CITY OF RENTON
1055 SOUTH GRADY WAY
RENTON, WASHINGTON 98057
RGI PROJECT NO. 2018-130
FAMILY FIRST COMMUNITY CENTER
16022 116TH AVENUE SOUTHEAST
RENTON, WASHINGTON 98058
JUNE 8, 2018
Geotechnical Engineering Report June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................................................................................... 1
2.0 PROJECT DESCRIPTION .................................................................................................................... 1
3.0 FIELD EXPLORATION AND LABORATORY TESTING ........................................................................... 1
4.0 SITE CONDITIONS ............................................................................................................................ 2
4.1 SURFACE .................................................................................................................................................. 2
4.2 GEOLOGY ................................................................................................................................................. 2
4.3 SOILS ....................................................................................................................................................... 2
4.4 GROUNDWATER ........................................................................................................................................ 2
4.5 SEISMIC CONSIDERATIONS ........................................................................................................................... 3
4.6 COAL MINE HAZARD .................................................................................................................................. 3
5.0 DISCUSSION AND RECOMMENDATIONS ......................................................................................... 4
5.1 GEOTECHNICAL CONSIDERATIONS ................................................................................................................. 4 5.2 EARTHWORK ............................................................................................................................................. 4
5.2.1 Erosion and Sediment Control ..................................................................................................... 4
5.2.2 Stripping ....................................................................................................................................... 5
5.2.3 Excavations................................................................................................................................... 5
5.2.4 Site Preparation ........................................................................................................................... 6
5.2.5 Structural Fill ................................................................................................................................ 6
5.2.6 Cut and Fill Slopes ........................................................................................................................ 8
5.2.7 Wet Weather Construction Considerations ................................................................................. 8
5.3 FOUNDATIONS .......................................................................................................................................... 9
5.4 RETAINING WALLS ................................................................................................................................... 10
5.5 SLAB-ON-GRADE CONSTRUCTION ............................................................................................................... 10
5.6 DRAINAGE .............................................................................................................................................. 10
5.6.1 Surface ....................................................................................................................................... 10
5.6.2 Subsurface .................................................................................................................................. 11
5.6.3 Infiltration .................................................................................................................................. 11
5.7 UTILITIES ................................................................................................................................................ 11
5.8 PAVEMENTS ............................................................................................................................................ 11
5.9 CONSTRUCTION CONSIDERATIONS ............................................................................................................... 12
6.0 ADDITIONAL SERVICES .................................................................................................................. 12
7.0 LIMITATIONS ................................................................................................................................. 12
LIST OF APPENDICES
Figure 1 ..................................................................................................................... Site Vicinity Map
Figure 2 ............................................................................................... Geotechnical Exploration Plan
Figure 3 ............................................................................................... Retaining Wall Drainage Detail
Figure 4 ....................................................................................................Typical Footing Drain Detail
Appendix A .......................................................................... Field Exploration and Laboratory Testing
Geotechnical Engineering Report June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
Executive Summary
This Executive Summary should be used in conjunction with the entire GER for design
and/or construction purposes. It should be recognized that specific details were not
included or fully developed in this section, and this GER must be read in its entirety for a
comprehensive understanding of the items contained herein. Section 7.0 should be read
for an understanding of limitations.
RGI’s geotechnical scope of work included the advancement of seven test borings to a
maximum depth of 16.5 feet below ground surface (bgs).
Based on the information obtained from our subsurface exploration, the site is suitable
for development of the proposed project. The following geotechnical considerations were
identified.
Soil Conditions: The site is underlain by up to 11 feet of fill comprised of loose to medium
dense silty sand with varying amounts of gravel over medium dense to very dense silty
sand with varying amounts of gravel, and localized silty sand, sandy gravel, and sand with
some silt and gravel.
Groundwater: Groundwater seepage was encountered at 15 feet bgs in two of the test
borings during our subsurface exploration.
Foundations: The proposed buildings can be supported on spread footing foundation
bearing on competent native soil or structural fill.
Slab-on-grade: Slab-on-grade floors can be supported on dense to medium dense native
soil or new structural fill.
Pavements: The following pavement sections are recommended for new driveway areas:
For flexible pavements: 2 inches of HMA over 6 inches of Crushed Rock Base
(CRB) over compacted subgrade.
For concrete driveways: 5 inches of concrete over 4 inches of CRB over
compacted subgrade
Construction Considerations: RGI recommends that the major earthwork be performed
in dry season from May to September.
Geotechnical Engineering Report 1 June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
1.0 Introduction
This Geotechnical Engineering Report (GER) presents the results of the geotechnical
engineering services provided for the Family First Community Center in Renton,
Washington. The purpose of this GER is to assess subsurface conditions and provide
geotechnical recommendations for building a one-story community center building. Our
scope of services included field explorations, laboratory testing, engineering analyses, and
preparation of this GER.
The recommendations in the following sections of this GER are based upon our current
understanding of the proposed site development as outlined below. RGI should review
the proposed site grading and utility plans once they are developed in order to confirm
the recommendations provided in this report are appropriate for the development as
proposed. In addition, RGI requests to review the final site grading plans and
specifications when available to verify that our project understanding is correct and that
our recommendations have been properly interpreted and incorporated into the project
design and construction.
2.0 Project Description
The site is located 16022 116th Avenue Southeast in Renton, Washington. The
approximate location of the site is shown on Figure 1.
The site includes a rectangular shaped parcel of land about 14.9 aces in size. The northern
portion of the site is occupied by a school building and facilities. The proposed
development will be located at the southwest corner of the property.
The proposed Family First Community Center building will be a one-story building about
30,000 square feet in size with a slab on grade floor. Our understanding of the project is
based on the Master Site Plan prepared by Baylis Architecture dated February 26, 2018.
RGI expects the proposed building will be a one-story, light-weight structure with a
maximum column load of less than 100 kips. Slab-on-grade floor loading of 150 pounds
per square foot (psf) are expected. RGI anticipates that grading with fill up to
approximately 10 feet will be needed in the existing stormwater pond area to reach the
design grade.
3.0 Field Exploration and Laboratory Testing
On May 23, 2018, RGI performed subsurface exploration using a tracked drill rig. A total
of seven test borings were advanced in the proposed development area. The approximate
exploration locations are shown on Figure 2.
Field logs of each exploration were prepared by the geologist who completed the borings.
These logs included visual classifications of the materials encountered during excavation
Geotechnical Engineering Report 2 June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
as well as our interpretation of the subsurface conditions between samples. The boring
logs included in Appendix A represent an interpretation of the field logs and include
modifications based on laboratory observation and analysis of the samples.
4.0 Site Conditions
4.1 SURFACE
The entire site includes a rectangular shaped parcel of land about 14.9 aces in size. The
proposed development area is located in the southwest portion of the site and is
approximately 3.35 acres in size. The project area is bound to the north and east by the
existing school building and facilities, to the south by residential properties, and to the
west by 116th Avenue Southeast.
The western portion of the proposed development area is a paved parking lot. An existing
storm water pond approximately 10 feet deep is located along the southern property line.
To the north of the pond, there is 5-foot hump area that appears to have been created by
the excavated soil from the pond excavation.
4.2 GEOLOGY
Review of the Geologic Map of King County, Washington by Derek B. Booth, etc (2002)
indicates that the site soil is mapped as till (Map Unit Qvt) which is compact diamict
containing subrounded to well-rounded clasts, glacially transported and deposited.
Generally forms undulating layers a few meters to a few tens of meters thick. The native
soil below the fill encountered during field exploration appears to match the description.
4.3 SOILS
The site is underlain by up to 11 feet of fill comprised of loose to medium dense silty sand
with varying amounts of gravel over medium dense to very dense silty sand with varying
amounts of gravel, and localized silty sand, sandy gravel, and sand with some silt and
gravel. More detailed descriptions of the subsurface conditions encountered are
presented in the test borings included in Appendix A.
4.4 GROUNDWATER
Groundwater seepage was encountered at 15 feet bgs in two of the test borings during
our subsurface exploration.
It should be recognized that fluctuations of the groundwater table will occur due to
seasonal variations in the amount of rainfall, runoff, and other factors not evident at the
time the explorations were performed. In addition, perched water can develop within
seams and layers contained in fill soils or higher permeability soils overlying less
permeable soils following periods of heavy or prolonged precipitation. Therefore,
Geotechnical Engineering Report 3 June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
groundwater levels during construction or at other times in the future may be higher or
lower than the levels indicated on the logs. Groundwater level fluctuations should be
considered when developing the design and construction plans for the project.
4.5 SEISMIC CONSIDERATIONS
Based on the 2012/2015 International Building Code (IBC), RGI recommends the follow
seismic parameters in Table 1 be used for design.
Table 1 IBC Seismic Parameters
2012/2015 IBC Parameter Value
Site Soil Class1 D2
Site Latitude 47.45859 N
Site Longitude 122.18416 W
Maximum considered earthquake spectral response acceleration
parameters (g) Ss = 1.399, S1 = 0.522
Spectral response acceleration parameters adjusted for site class
(g) Sms = 1.399, Sm1 = 0.783
Design spectral response acceleration parameters (g) Sds = 0.933, Sd1 = 0.522
1 Note: In general accordance with the USGS 2012/2015 International Building Code. IBC Site Class is based on the average
characteristics of the upper 100 feet of the subsurface profile.
2 Note: The 2012/2015 International Building Code requires a site soil profile determination extending to a depth of 100 feet for
seismic site classification. The current scope of our services does not include the required 100 foot soil profile determination. Hand
auger borings extended to a maximum depth of 16.5 feet, and this seismic site class definition considers that similar soil continues
below the maximum depth of the subsurface exploration.
Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength
due to an increase in water pressure induced by vibrations from a seismic event.
Liquefaction mainly affects geologically recent deposits of fine-grained sands that are
below the groundwater table. Soils of this nature derive their strength from intergranular
friction. The generated water pressure or pore pressure essentially separates the soil
grains and eliminates this intergranular friction, thus reducing or eliminating the soil’s
strength.
RGI reviewed the results of the field and laboratory testing and assessed the potential for
liquefaction of the site’s soil during an earthquake in the area. The site is underlain by till
which is considered not liquefiable.
4.6 COAL MINE HAZARD
RGI has reviewed the City of Renton Coal Mine Hazards map dated November 12, 2014.
The project site is not mapped as a coal mine hazard area.
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Family First Community Center, Renton, Washington RGI Project No. 2018-130
5.0 Discussion and Recommendations
5.1 GEOTECHNICAL CONSIDERATIONS
Based on our study, the site is suitable for the proposed construction from a geotechnical
standpoint. RGI recommends that proposed buildings be supported on spread footings
bearing on medium dense native soil or structural fill. The slab-on-grade can be similarly
supported on medium dense native soil or structural fill.
Detailed recommendations regarding the above issues and other geotechnical design
considerations are provided in the following sections. These recommendations should be
incorporated into the final design drawings and construction specifications.
5.2 EARTHWORK
RGI expects that site grading will consist of cut in the high area of the site and fill in the
pond area to achieve building and pavement grades and excavation for utilities including
storm, water, sanitary sewer, and other utilities.
5.2.1 EROSION AND SEDIMENT CONTROL
Potential sources or causes of erosion and sedimentation depend on construction
methods, slope length and gradient, amount of soil exposed and/or disturbed, soil type,
construction sequencing and weather. The impacts on erosion-prone areas can be
reduced by implementing an erosion and sedimentation control plan. The plan should be
designed in accordance with applicable city and/or county standards.
RGI recommends the following erosion control Best Management Practices (BMPs):
Scheduling site preparation and grading for the drier summer and early fall
months and undertaking activities that expose soil during periods of little or no
rainfall
Establishing a quarry spall construction entrance
Installing siltation control fencing or anchored straw or coir wattles on the
downhill side of work areas
Covering soil stockpiles with anchored plastic sheeting
Revegetating or mulching exposed soils with a minimum 3-inch thickness of straw
if surfaces will be left undisturbed for more than one day during wet weather or
one week in dry weather
Directing runoff away from exposed soils and slopes
Minimizing the length and steepness of slopes with exposed soils and cover
excavation surfaces with anchored plastic sheeting (Graded and disturbed slopes
should be tracked in place with the equipment running perpendicular to the slope
contours so that the track marks provide a texture to help resist erosion and
Geotechnical Engineering Report 5 June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
channeling. Some sloughing and raveling of slopes with exposed or disturbed soil
should be expected.)
Decreasing runoff velocities with check dams, straw bales or coir wattles
Confining sediment to the project site
Inspecting and maintaining erosion and sediment control measures frequently
(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.)
Permanent erosion protection should be provided by reestablishing vegetation using
hydroseeding and/or landscape planting. Until the permanent erosion protection is
established, site monitoring should be performed by qualified personnel to evaluate the
effectiveness of the erosion control measures. Provisions for modifications to the erosion
control system based on monitoring observations should be included in the erosion and
sedimentation control plan.
5.2.2 STRIPPING
Stripping efforts should include removal of vegetation, organic materials, and deleterious
debris from areas slated for building, pavement, and utility construction. Topsoil and
rootmass is generally less than 12 inches across the site. Deeper areas of stripping may be
required in heavily vegetated areas of the site. The existing pond should be dry before
filling and the wet soil and vegetation should be removed before filling.
5.2.3 EXCAVATIONS
All temporary cut slopes associated with the site and utility excavations should be
adequately inclined to prevent sloughing and collapse. The shallow native soil is classified
as Group C soil and native dense soil is classified Group A.
Accordingly, for excavations more than 4 feet but less than 20 feet in depth, the
temporary side slopes should be laid back with a minimum slope inclination of 1.5H:1V
(Horizontal:Vertical) in the upper 5 feet and 3/4H:1V in dense native soil. If there is
insufficient room to complete the excavations in this manner, or excavations greater than
20 feet in depth are planned, using temporary shoring to support the excavations should
be considered.
For open cuts at the site, RGI recommends:
No traffic, construction equipment, stockpiles or building supplies are allowed at
the top of cut slopes within a distance of at least 5 feet from the top of the cut
Exposed soil along the slope is protected from surface erosion using waterproof
tarps and/or plastic sheeting
Construction activities are scheduled so that the length of time the temporary cut
is left open is minimized
Geotechnical Engineering Report 6 June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
Surface water is diverted away from the excavation
The general condition of slopes should be observed periodically by a geotechnical
engineer to confirm adequate stability and erosion control measures
In all cases, however, appropriate inclinations will depend on the actual soil and
groundwater conditions encountered during earthwork. Ultimately, the site contractor
must be responsible for maintaining safe excavation slopes that comply with applicable
OSHA or WISHA guidelines.
5.2.4 SITE PREPARATION
After stripping, grubbing, and prior to placement of structural fill, RGI recommends
proofrolling building and pavement subgrades and areas to receive structural fill. These
areas should be proofrolled under the observation of RGI and compacted to a firm and
unyielding condition in order to achieve a minimum compaction level of 95 percent of the
modified proctor maximum dry density as determined by the American Society of Testing
and Materials D1557-09 Standard Test Methods for Laboratory Compaction
Characteristics of Soil Using Modified Effort (ASTM D1557).
Proofrolling and adequate subgrade compaction can only be achieved when the soils are
within approximately ± 2 percent moisture content of the optimum moisture content.
Soils that appear firm after stripping and grubbing may be proofrolled with a heavy
compactor, loaded double-axle dump truck, or other heavy equipment under the
observation of an RGI representative. This observer will assess the subgrade conditions
prior to filling. The need for or advisability of proofrolling due to soil moisture conditions
should be determined at the time of construction.
Subgrade soils that become disturbed due to elevated moisture conditions should be
overexcavated to reveal firm, non-yielding, non-organic soils and backfilled with
compacted structural fill. In order to maximize utilization of site soils as structural fill, RGI
recommends that the earthwork portion of this project be completed during extended
periods of warm and 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 will require additional
mitigative measures beyond that which would be expected during the drier summer and
fall months.
5.2.5 STRUCTURAL FILL
RGI recommends fill below the foundation and floor slab, behind retaining walls, and
below pavement and hardscape surfaces be placed in accordance with the following
recommendations for structural fill.
The suitability of excavated site soils and import soils for compacted structural fill use will
depend on the gradation and moisture content of the soil when it is placed. As the
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Family First Community Center, Renton, Washington RGI Project No. 2018-130
amount of fines (that portion passing the U.S. No. 200 sieve) increases, soil becomes
increasingly sensitive to small changes in moisture content and adequate compaction
becomes more difficult or impossible to achieve. Soils containing more than about 5
percent fines cannot be consistently compacted to a dense, non-yielding condition when
the moisture content is more than 2 percent above or below optimum. Optimum
moisture content is the moisture that results in the greatest compacted dry density with a
specified compactive effort.
Non-organic site soils are only considered suitable for structural fill provided that their
moisture content is within about 2 percent of the optimum moisture level as determined
by ASTM D1557. Excavated site soils may not be suitable for re-use as structural fill
depending on the moisture content and weather conditions at the time of construction. If
soils are stockpiled for future reuse and wet weather is anticipated, the stockpile should
be protected with plastic sheeting that is securely anchored. Even during dry weather,
moisture conditioning (such as, windrowing and drying) of site soils to be reused as
structural fill may be required. Even during the summer, delays in grading can occur due
to excessively high moisture conditions of the soils or due to precipitation. If wet weather
occurs, the upper wetted portion of the site soils may need to be scarified and allowed to
dry prior to further earthwork, or may need to be wasted from the site.
The native soil contains a large percentage of fines and is moisture sensitive, it may
necessary to import structural fill if the construction occurs in wet season. Import
structural fill should meet the gradation requirements listed in Table 2 for wet weather
conditions. For dry season earthwork, the percent passing the No. 200 may be increased
to 10 percent maximum or materials meeting the 2012 Washington State Department of
Transportation (WSDOT) Standard Specifications for Road, Bridge, and Municipal
Construction, Section 9-03.14(1) may be used.
Table 2 Structural Fill Gradation
U.S. Sieve Size Percent Passing
4 inches 100
No. 4 sieve 75 percent
No. 200 sieve 5 percent *
*Based on minus 3/4 inch fraction.
Prior to use, an RGI representative should observe and test all materials imported to the
site for use as structural fill. Structural fill materials should be placed in uniform loose
layers not exceeding 12 inches and compacted as specified in Table 3. The soil’s maximum
density and optimum moisture should be determined by ASTM D1557.
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Family First Community Center, Renton, Washington RGI Project No. 2018-130
Table 3 Structural Fill Compaction ASTM D1557
Location Material Type
Minimum
Compaction
Percentage
Moisture Content
Range
Foundations On-site granular or approved
imported fill soils: 95 +2 -2
Retaining Wall Backfill On-site granular or approved
imported fill soils: 92 +2 -2
Slab-on-grade On-site granular or approved
imported fill soils: 95 +2 -2
General Fill (non-
structural areas)
On-site soils or approved
imported fill soils: 90 +3 -2
Pavement – Subgrade
and Base Course On-site granular or approved
imported fill soils: 95 +2 -2
Placement and compaction of structural fill should be observed by RGI. A representative
number of in-place density tests should be performed as the fill is being placed to confirm
that the recommended level of compaction is achieved.
5.2.6 CUT AND FILL SLOPES
All permanent cut and fill slopes should be graded with a finished inclination no greater
than 2H:1V. Upon completion of construction, the slope face should be trackwalked,
compacted and vegetated, or provided with other physical means to guard against
erosion. All fill placed for slope construction should meet the structural fill requirements
as described in Section 5.2.5.
Final grades at the top of the slopes must promote surface drainage away from the slope
crest. Water must not be allowed to flow in an uncontrolled fashion over the slope face. If
it is necessary to direct surface runoff towards the slope, it should be controlled at the
top of the slope, piped in a closed conduit installed on the slope face, and taken to an
appropriate point of discharge beyond the toe of the slope.
5.2.7 WET WEATHER CONSTRUCTION CONSIDERATIONS
RGI recommends that preparation for site grading and construction include procedures
intended to drain ponded water, control surface water runoff, and to collect shallow
subsurface seepage zones in excavations where encountered. It will not be possible to
successfully compact the subgrade or utilize on-site soils as structural fill if accumulated
water is not drained prior to grading or if drainage is not controlled during construction.
Attempting to grade the site without adequate drainage control measures will reduce the
amount of on-site soil effectively available for use, increase the amount of select import
fill materials required, and ultimately increase the cost of the earthwork phases of the
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Family First Community Center, Renton, Washington RGI Project No. 2018-130
project. Free water should not be allowed to pond on the subgrade soils. RGI anticipates
that the use of berms and shallow drainage ditches, with sumps and pumps in utility
trenches, will be required for surface water control during wet weather and/or wet site
conditions.
5.3 FOUNDATIONS
Following site preparation and grading, the proposed building foundations may be
supported on conventional spread footings bearing on medium dense native soil or
structural fill. The existing fill may be suitable for support of foundations and should be
evaluated during construction. Where loose soils or other unsuitable soils are
encountered in the proposed building footprint, they should be overexcavated and
backfilled with structural fill.
Perimeter foundations exposed to weather should be at a minimum depth of 18 inches
below final exterior grades. Interior foundations can be constructed at any convenient
depth below the floor slab. Finished grade is defined as the lowest adjacent grade within
5 feet of the foundation for perimeter (or exterior) footings and finished floor level for
interior footings.
Table 4 Foundation Design
Design Parameter Value
Allowable Bearing Capacity 2,500 psf1
Friction Coefficient 0.25
Passive pressure (equivalent fluid pressure) 250 pcf2
Minimum foundation dimensions Columns: 24 inches
Walls: 16 inches
1 psf = pounds per square foot
2 pcf = pounds per cubic foot
The allowable foundation bearing pressures apply to dead loads plus design live load
conditions. For short-term loads, such as wind and seismic, a 1/3 increase in this
allowable capacity may be used. At perimeter locations, RGI recommends not including
the upper 12 inches of soil in the computation of passive pressures because it can be
affected by weather or disturbed by future grading activity. The passive pressure value
assumes the foundation will be constructed neat against competent soil or backfilled with
structural fill as described in Section 5.2.5. The recommended base friction and passive
resistance value includes a safety factor of about 1.5.
With spread-footing foundations designed in accordance with the recommendations in
this section, maximum total and differential post-construction settlements of 1 inch and
1/2 inch, respectively, should be expected.
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Family First Community Center, Renton, Washington RGI Project No. 2018-130
5.4 RETAINING WALLS
RGI recommends cast-in-place concrete walls be used for basement wall (if needed). The
magnitude of earth pressure development on retaining walls will partly depend on the
quality of the wall backfill. RGI recommends placing and compacting wall backfill as
structural fill. Wall drainage will be needed behind the wall face. A typical retaining wall
drainage detail is shown on Figure 3. With wall backfill placed and compacted as
recommended, and drainage properly installed, RGI recommends using the values in the
following table for design.
Table 5 Retaining Wall Design
Design Parameter Value
Allowable Bearing Capacity 2,500 psf
Active Earth Pressure (unrestrained walls) 35 pcf
At-rest Earth Pressure (restrained walls) 50 pcf
For seismic design, an additional uniform load of 7 times the wall height (H) for
unrestrained walls and 14H for restrained walls should be applied to the wall surface.
Friction at the base of foundations and passive earth pressure will provide resistance to
these lateral loads. Values for these parameters are provided in Section 5.3.
5.5 SLAB-ON-GRADE CONSTRUCTION
Once site preparation has been completed as described in Section 5.2, suitable support
for slab-on-grade construction should be provided. Immediately below the floor slab, RGI
recommends placing a 4-inch-thick capillary break layer of clean, free-draining pea gravel,
washed rock, or crushed rock that has less than 5 percent passing the U.S. No. 200 sieve.
This material will reduce the potential for upward capillary movement of water through
the underlying soil and subsequent wetting of the floor slab.
Where moisture by vapor transmission is undesirable, an 8- to 10-millimeter-thick plastic
membrane should be placed on a 4-inch-thick layer of clean gravel or rock. For the
anticipated floor slab loading, we estimate post-construction floor settlements of ¼- to ½-
inch.
5.6 DRAINAGE
5.6.1 SURFACE
Final exterior grades should promote free and positive drainage away from the building
area. Water must not be allowed to pond or collect adjacent to foundations or within the
immediate building area. For non-pavement locations, RGI recommends providing a
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Family First Community Center, Renton, Washington RGI Project No. 2018-130
minimum drainage gradient of 3 percent for a minimum distance of 10 feet from the
building perimeter. In paved locations, a minimum gradient of 1 percent should be
provided unless provisions are included for collection and disposal of surface water
adjacent to the structure.
5.6.2 SUBSURFACE
RGI recommends installing perimeter foundation drain as shown on Figure 4. The
retaining wall drains, perimeter foundation drain, and roof downspouts should be
tightlined separately to an approved discharge facility. Subsurface drains must be laid
with a gradient sufficient to promote positive flow to a controlled point of approved
discharge.
5.6.3 INFILTRATION
Based on the soil encountered, the native soil is not suitable for infiltration.
5.7 UTILITIES
Utility pipes should be bedded and backfilled in accordance with American Public Works
Association (APWA) specifications. For site utilities located within the right-of-ways,
bedding and backfill should be completed in accordance with City of Renton
specifications. At a minimum, trench backfill should be placed and compacted as
structural fill, as described in Section 5.2.5. Where utilities occur below unimproved
areas, the degree of compaction can be reduced to a minimum of 90 percent of the soil’s
maximum density as determined by ASTM D1557. If the native soil becomes unsuitable
for use as structural fill, imported structural fill will be necessary for trench backfill as
recommended in Section 5.2.5.
5.8 PAVEMENTS
RGI recommends that the driveway to the new garage be stripped and repaved.
Pavement subgrades should be prepared as described in Section 5.2 of this GER and as
discussed below. Regardless of the relative compaction achieved, the subgrade must be
firm and relatively unyielding before paving. This condition should be verified by
proofrolling with heavy construction equipment or hand probe by inspector.
With the pavement subgrade prepared as described above, RGI recommends the
following pavement section with flexible asphalt concrete surfacing.
For private asphalt driveways or parking: 2 inches of hot mix asphalt over 6
inches of crushed rock base (CRB) over compacted subgrade;
The asphalt paving materials used should conform to the Washington State Department
of Transportation (WSDOT) specifications for Hot Mix Asphalt Class 1/2 inch and CRB
surfacing.
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Family First Community Center, Renton, Washington RGI Project No. 2018-130
If concrete driveway is preferred, the following section can be used.
For concrete driveways: 5 inches of concrete over 4 inches of CRB over
compacted subgrade
Long-term pavement performance will depend on surface drainage. A poorly-drained
pavement section will be subject to premature failure as a result of surface water
infiltrating into the subgrade soils and reducing their supporting capability.
For optimum pavement performance, surface drainage gradients of no less than 2
percent are recommended. Also, some degree of longitudinal and transverse cracking of
the pavement surface should be expected over time. Regular maintenance should be
planned to seal cracks when they occur.
5.9 CONSTRUCTION CONSIDERATIONS
An important construction consideration is the weather and its impact on construction
scheduling. Although it is not impossible, winter construction will be more difficult and
will increase construction costs. RGI highly recommends that the major earthwork be
performed in dry season from May to September.
6.0 Additional Services
RGI is available to provide further geotechnical consultation throughout the design phase
of the project. RGI should review the grading and utilities plans in order to verify that
earthwork and foundation recommendations in this report are appropriate and provide
supplemental recommendations as necessary.
RGI should be contracted to provide geotechnical engineering and construction
monitoring services during. The integrity of the earthwork and construction depends on
proper site preparation and procedures. In addition, engineering decisions may arise in
the field in the event that variations in subsurface conditions become apparent.
Construction monitoring services are not part of this scope of work. RGI can provide an
estimate for these services once the construction plans and schedule have been
developed.
7.0 Limitations
This GER is the property of RGI, City of Renton and her designated agents. Within the
limits of the scope and budget, this GER was prepared in accordance with generally
accepted geotechnical engineering practices in the area at the time this report was
issued. This GER is intended for specific application to the Family First Community Center
at 16022 116th Avenue Southeast in Renton, Washington, and for the exclusive use of the
City of Renton and its authorized representatives. No other warranty, expressed or
Geotechnical Engineering Report 13 June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
implied, is made. Site safety, excavation support, and dewatering requirements are the
responsibility of others.
The scope of services for this project does not include either specifically or by implication
any environmental or biological (for example, mold, fungi, bacteria) assessment of the
site or identification or prevention of pollutants, hazardous materials, or conditions. If the
owner is concerned about the potential for such contamination or pollution, we can
provide a proposal for these services.
The analyses and recommendations presented in this GER are based upon review of the
previous explorations on the site by Geotechnical Investigations Group. Variations in soil
conditions can occur, the nature and extent of which may not become evident until
construction. If variations appear evident, RGI should be requested to reevaluate the
recommendations in this GER prior to proceeding with construction.
It is client’s responsibility to see that all parties to the project, including the designers,
contractors, subcontractors, are made aware of this GER in its entirety. The use of
information contained in this GER for bidding purposes should be done at the contractor’s
option and risk.
USGS, 2014, Renton, Washington
7.5-Minute Quadrangle
Approximate Scale: 1"=1000'
0 500 1000 2000 N
Site Vicinity Map
Figure 1
06/2018
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Family First Community Center
RGI Project Number
2018-130
Date Drawn:
Address: 16022 116th Avenue Southeast, Renton, Washington 98058
SITE
B-1B-2B-3B-4B-5B-6B-706/2018Corporate Office17522 Bothell Way NortheastBothell, Washington 98011Phone: 425.415.0551Fax: 425.415.0311Family First Community CenterRGI Project Number2018-130Date Drawn:Address: 16022 116th Avenue Southeast, Renton, Washington 98058Geotechnical Exploration PlanFigure 2Approximate Scale: 1"=120'060120240N= Boring by RGI, 5/23/18= Site boundary
Incliniations)
12" Over the Pipe
3" Below the Pipe
Perforated Pipe
4" Diameter PVC
Compacted Structural
Backfill (Native or Import)
12" min.
Filter Fabric Material
12" Minimum Wide
Free-Draining Gravel
Slope to Drain
(See Report for
Appropriate
Excavated Slope
06/2018
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Family First Community Center
RGI Project Number
2018-130
Date Drawn:
Address: 16022 116th Avenue Southeast, Renton, Washington 98058
Retaining Wall Drainage Detail
Figure 3
Not to Scale
3/4" Washed Rock or Pea Gravel
4" Perforated Pipe
Building Slab
Structural
Backfill
Compacted
Filter Fabric
06/2018
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Family First Community Center
RGI Project Number
2018-130
Date Drawn:
Address: 16022 116th Avenue Southeast, Renton, Washington 98058
Typical Footing Drain Detail
Figure 4
Not to Scale
Geotechnical Engineering Report June 8, 2018
Family First Community Center, Renton, Washington RGI Project No. 2018-130
APPENDIX A
FIELD EXPLORATION AND LABORATORY TESTING
On May 23, 2018, RGI performed field explorations using a tracked drill rig. RGI explored
subsurface soil conditions at the site by observing the drilling of 7 test borings to a
maximum depth of 16.5 feet below existing grade. The boring locations are shown on
Figure 2. The boring locations were approximately determined by measurements from
existing site features and topography.
A geologist from our office conducted the field exploration and classified the soil
conditions encountered, maintained a log of each test exploration, obtained
representative soil samples, and observed pertinent site features. All soil samples were
visually classified in accordance with the Unified Soil Classification System (USCS).
Representative soil samples obtained from the explorations were placed in closed
containers and taken to our laboratory for further examination and testing. As a part of
the laboratory testing program, the soil samples were classified in our in-house laboratory
based on visual observation, texture, plasticity, and the limited laboratory testing
described below.
Moisture Content Determinations
Moisture content determinations were performed in accordance with ASTM D2216-10
Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil
and Rock by Mass (ASTM D2216) on representative samples obtained from the
exploration in order to aid in identification and correlation of soil types. The moisture
content of typical samples were measured and is reported on the test pit logs.
Grain Size Analysis
A grain size analysis indicates the range in diameter of soil particles included in a
particular sample. Grain size analyses was determined using D6913-04(2009) Standard
Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis (ASTM
D6913) on four of the samples.
Project Name:Family First Community Center
Project Number:2018-130
Client:City of Renton
Boring No.:B-1
Date(s) Drilled:5/23/2018
Drilling Method(s):Hollow Stem Auger
Drill Rig Type:Track Rig
Groundwater Level:Seepage at 15'
Borehole Backfill:Bentonite Chips
Logged By:ELW
Drill Bit Size/Type:8" auger
Drilling Contractor:Bortec
Sampling Method(s):SPT
Location:16022 116th Avenue Southeast, Renton, Washington
Surface Conditions:Asphalt
Total Depth of Borehole:16.5 feet bgs
Approximate
Surface Elevation:N/A
Hammer Data :140 lb, 30" drop, rope and
cathead
USCS SymbolAsphalt
Fill
SM
GP
SM Moisture (%)12
17
20
11
17
13Recovery (%)Graphic LogRQD (%)MATERIAL DESCRIPTION
6" asphalt over crushed rock base
Gray silty SAND with some gravel, medium dense, moist (Fill)
Little recovery
Becomes brown to gray, moist to wet, trace organics
Brown silty SAND with some gravel, medium dense, wet
22% fines
Brown sandy GRAVEL, very dense, saturated
Tan silty SAND, very dense, moist
Boring terminated at 16' 6"Depth (feet)0
5
10
15 Sample TypeSampling Resistance, blows/ft21
14
13
74Elevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Family First Community Center
Project Number:2018-130
Client:City of Renton
Boring No.:B-2
Date(s) Drilled:5/23/2018
Drilling Method(s):Hollow Stem Auger
Drill Rig Type:Track Rig
Groundwater Level:Not Encountered
Borehole Backfill:Bentonite Chips
Logged By:ELW
Drill Bit Size/Type:8" auger
Drilling Contractor:Bortec
Sampling Method(s):SPT
Location:16022 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Borehole:16.33 feet bgs
Approximate
Surface Elevation:N/A
Hammer Data :140 lb, 30" drop, rope and
cathead
USCS SymbolTPSL
Fill
SM Moisture (%)10
12
16
11Recovery (%)Graphic LogRQD (%)MATERIAL DESCRIPTION
Topsoil
Light to dark brown silty SAND with some gravel, medium dense, moist (Fill)
23% fines
Becomes gray to brown, very dense, contains organics
Gray to brown silty SAND with some gravel, very dense, moist
Boring terminated at 16' 5"Depth (feet)0
5
10
15 Sample TypeSampling Resistance, blows/ft21
21
71
90/11"Elevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Family First Community Center
Project Number:2018-130
Client:City of Renton
Boring No.:B-3
Date(s) Drilled:5/23/2018
Drilling Method(s):Hollow Stem Auger
Drill Rig Type:Track Rig
Groundwater Level:Seepage at 15'
Borehole Backfill:Bentonite Chips
Logged By:ELW
Drill Bit Size/Type:8" auger
Drilling Contractor:Bortec
Sampling Method(s):SPT
Location:16022 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Borehole:15.75 feet bgs
Approximate
Surface Elevation:N/A
Hammer Data :140 lb, 30" drop, rope and
cathead
USCS SymbolTPSL
Fill
SM
SP-SM Moisture (%)11
13
11
17Recovery (%)Graphic LogRQD (%)MATERIAL DESCRIPTION
Topsoil
Gray silty SAND with some gravel, medium dense, wet (Fill)
Gray silty SAND with some gravel, very dense, moist to wet (Glacial Till)
Becomes moist
Brown SAND with some silt and gravel, very dense, water bearing
Boring terminated at 15' 9"Depth (feet)0
5
10
15 Sample TypeSampling Resistance, blows/ft12
50/5"
50/6"
50/3"Elevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Family First Community Center
Project Number:2018-130
Client:City of Renton
Boring No.:B-4
Date(s) Drilled:5/23/2018
Drilling Method(s):Hollow Stem Auger
Drill Rig Type:Track Rig
Groundwater Level:Not Encountered
Borehole Backfill:Bentonite Chips
Logged By:ELW
Drill Bit Size/Type:8" auger
Drilling Contractor:Bortec
Sampling Method(s):SPT
Location:16022 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Borehole:15.5 feet bgs
Approximate
Surface Elevation:N/A
Hammer Data :140 lb, 30" drop, rope and
cathead
USCS SymbolTPSL
Fill
SM Moisture (%)12
9
9
10Recovery (%)Graphic LogRQD (%)MATERIAL DESCRIPTION
Topsoil
Brown silty SAND, medium dense, moist
Becomes dense
Gray silty SAND with some gravel, dense, moist (Glacial Till)
Becomes tan, very dense
Boring terminated at 15' 6"Depth (feet)0
5
10
15 Sample TypeSampling Resistance, blows/ft38
43
50/4"
50/6"Elevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Family First Community Center
Project Number:2018-130
Client:City of Renton
Boring No.:B-5
Date(s) Drilled:5/23/2018
Drilling Method(s):Hollow Stem Auger
Drill Rig Type:Track Rig
Groundwater Level:Not Encountered
Borehole Backfill:Bentonite Chips
Logged By:ELW
Drill Bit Size/Type:8" auger
Drilling Contractor:Bortec
Sampling Method(s):SPT
Location:16022 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Borehole:15.42 feet bgs
Approximate
Surface Elevation:N/A
Hammer Data :140 lb, 30" drop, rope and
cathead
USCS SymbolTPSL
SM Moisture (%)12
9
14
7Recovery (%)Graphic LogRQD (%)MATERIAL DESCRIPTION
Topsoil
Gray silty SAND with trace gravel, medium dense, moist to wet (Glacial Till)
31% fines
Becomes very dense
Becomes moist
Boring terminated at 15' 5"Depth (feet)0
5
10
15 Sample TypeSampling Resistance, blows/ft25
61
50/6"
50/5"Elevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Family First Community Center
Project Number:2018-130
Client:City of Renton
Boring No.:B-6
Date(s) Drilled:5/23/2018
Drilling Method(s):Hollow Stem Auger
Drill Rig Type:Track Rig
Groundwater Level:Not Encountered
Borehole Backfill:Bentonite Chips
Logged By:ELW
Drill Bit Size/Type:8" auger
Drilling Contractor:Bortec
Sampling Method(s):SPT
Location:16022 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Borehole:16.5 feet bgs
Approximate
Surface Elevation:N/A
Hammer Data :140 lb, 30" drop, rope and
cathead
USCS SymbolTPSL
SM
SM
SP-SM Moisture (%)12
14
9
9Recovery (%)Graphic LogRQD (%)MATERIAL DESCRIPTION
Topsoil
Tan silty SAND with some gravel, medium dense, moist
Becomes medium dense to dense, little recovery
Becomes medium dense, mottled
Gray silty SAND with some gravel, very dense, moist
Brown SAND with some silt and gravel, very dense, moist to wet
Boring terminated at 16.5'Depth (feet)0
5
10
15 Sample TypeSampling Resistance, blows/ft30
17
67
73Elevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Family First Community Center
Project Number:2018-130
Client:City of Renton
Boring No.:B-7
Date(s) Drilled:5/23/2018
Drilling Method(s):Hollow Stem Auger
Drill Rig Type:Track Rig
Groundwater Level:Not Encountered
Borehole Backfill:Bentonite Chips
Logged By:ELW
Drill Bit Size/Type:8" auger
Drilling Contractor:Bortec
Sampling Method(s):SPT
Location:16022 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Borehole:16.5 feet bgs
Approximate
Surface Elevation:N/A
Hammer Data :140 lb, 30" drop, rope and
cathead
USCS SymbolTPSL
Fill
SM
SM Moisture (%)16
16
22
14Recovery (%)Graphic LogRQD (%)MATERIAL DESCRIPTION
Topsoil
Brown silty SAND with some gravel, loose moist to wet (Fill)
Becomes medium dense, contains organics
33% fines
Brown to gray silty SAND with trace gravel, medium dense, moist to wet
Gray silty SAND with some gravel, medium dense, wet
Boring terminated at 16.5'Depth (feet)0
5
10
15 Sample TypeSampling Resistance, blows/ft7
24
12
22Elevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Family First Community Center
Project Number:2018-130
Client:City of Renton
Key to Log of Boring
USCS SymbolMoisture (%)Recovery (%)Graphic LogRQD (%)MATERIAL DESCRIPTIONDepth (feet)Sample TypeSampling Resistance, blows/ftElevation (feet)1 2 3 4 5 6 7 8 9 10
COLUMN DESCRIPTIONS
1 Elevation (feet): Elevation (MSL, feet).
2 Depth (feet): Depth in feet below the ground surface.
3 Sample Type: Type of soil sample collected at the depth interval
shown.
4 Sampling Resistance, blows/ft: Number of blows to advance driven
sampler one foot (or distance shown) beyond seating interval
using the hammer identified on the boring log.
5 RQD (%): Rock Quality Designation is a relative index of the rock
mass quality calculated by comparing the cumulative length of
intact pieces of core exceeding 100 mm in length to the cored
interval length.
6 Recovery (%): Core Recovery Percentage is determined based on
a ratio of the length of core sample recovered compared to the
cored interval length.
7 USCS Symbol: USCS symbol of the subsurface material.
8 Graphic Log: Graphic depiction of the subsurface material
encountered.
9 MATERIAL DESCRIPTION: Description of material encountered.
May include consistency, moisture, color, and other descriptive
text.
10 Moisture (%): Moisture, expressed as a water content.
FIELD AND LABORATORY TEST ABBREVIATIONS
CHEM: Chemical tests to assess corrosivity
COMP: Compaction test
CONS: One-dimensional consolidation test
LL: Liquid Limit, percent
PI: Plasticity Index, percent
SA: Sieve analysis (percent passing No. 200 Sieve)
UC: Unconfined compressive strength test, Qu, in ksf
WA: Wash sieve (percent passing No. 200 Sieve)
MATERIAL GRAPHIC SYMBOLS
Asphaltic Concrete (AC)
AF
Poorly graded GRAVEL (GP)
Silty SAND (SM)
Poorly graded SAND with Silt (SP-SM)
Topsoil
TYPICAL SAMPLER GRAPHIC SYMBOLS
Auger sampler
Bulk Sample
3-inch-OD California w/
brass rings
CME Sampler
Grab Sample
2.5-inch-OD Modified
California w/ brass liners
Pitcher Sample
2-inch-OD unlined split
spoon (SPT)
Shelby Tube (Thin-walled,
fixed head)
OTHER GRAPHIC SYMBOLS
Water level (at time of drilling, ATD)
Water level (after waiting)
Minor change in material properties within a
stratum
Inferred/gradational contact between strata
?Queried contact between strata
GENERAL NOTES
1: Soil classifications are based on the Unified Soil Classification System. Descriptions and stratum lines are interpretive, and actual lithologic changes may be
gradual. Field descriptions may have been modified to reflect results of lab tests.
2: Descriptions on these logs apply only at the specific boring locations and at the time the borings were advanced. They are not warranted to be representative
of subsurface conditions at other locations or times.
Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Family First Community Center SAMPLE ID/TYPE B-1
PROJECT NO.2018-130 SAMPLE DEPTH 11 Feet
TECH/TEST DATE LC 5/28/2018 DATE RECEIVED 5/28/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)385.8 Weight Of Sample (gm)349.2
Wt Dry Soil & Tare (gm) (w2)349.2 Tare Weight (gm) 15.8
Weight of Tare (gm) (w3)15.8 (W6) Total Dry Weight (gm) 333.4
Weight of Water (gm) (w4=w1-w2) 36.6 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3) 333.4 Cumulative
Moisture Content (%) (w4/w5)*100 11 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.8 0.00 0.00 100.00 cobbles
% C GRAVEL 7.4 3.0"15.8 0.00 0.00 100.00 coarse gravel
% F GRAVEL 10.9 2.5" coarse gravel
% C SAND 6.0 2.0" coarse gravel
% M SAND 17.0 1.5"15.8 0.00 0.00 100.00 coarse gravel
% F SAND 36.8 1.0" coarse gravel
% FINES 21.8 0.75"40.6 24.80 7.44 92.56 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"57.4 41.60 12.48 87.52 fine gravel
D10 (mm)#4 77.1 61.30 18.39 81.61 coarse sand
D30 (mm)#10 97.2 81.40 24.42 75.58 medium sand
D60 (mm)#20 medium sand
Cu #40 153.9 138.10 41.42 58.58 fine sand
Cc #60 fine sand
#100 245.5 229.70 68.90 31.10 fine sand
#200 276.6 260.80 78.22 21.78 fines
PAN 349.2 333.40 100.00 0.00 silt/clay
322 306.2 91.841632 8.15836833
DESCRIPTION Silty SAND with some gravel
USCS SM
Prepared For: City of Renton Reviewed By: ELW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3" 2" 1" .75" .375" #4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Family First Community Center SAMPLE ID/TYPE B-2
PROJECT NO.2018-130 SAMPLE DEPTH 2.5 Feet
TECH/TEST DATE LC 5/28/2018 DATE RECEIVED 5/28/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)278.1 Weight Of Sample (gm)255.1
Wt Dry Soil & Tare (gm) (w2)255.1 Tare Weight (gm) 15.5
Weight of Tare (gm) (w3)15.5 (W6) Total Dry Weight (gm) 239.6
Weight of Water (gm) (w4=w1-w2) 23.0 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3) 239.6 Cumulative
Moisture Content (%) (w4/w5)*100 10 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.5 0.00 0.00 100.00 cobbles
% C GRAVEL 15.9 3.0"15.5 0.00 0.00 100.00 coarse gravel
% F GRAVEL 7.6 2.5" coarse gravel
% C SAND 8.6 2.0" coarse gravel
% M SAND 18.0 1.5"15.5 0.00 0.00 100.00 coarse gravel
% F SAND 27.2 1.0" coarse gravel
% FINES 22.6 0.75"53.6 38.10 15.90 84.10 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"57.3 41.80 17.45 82.55 fine gravel
D10 (mm)#4 71.9 56.40 23.54 76.46 coarse sand
D30 (mm)#10 92.5 77.00 32.14 67.86 medium sand
D60 (mm)#20 medium sand
Cu #40 135.7 120.20 50.17 49.83 fine sand
Cc #60 fine sand
#100 182.5 167.00 69.70 30.30 fine sand
#200 200.9 185.40 77.38 22.62 fines
PAN 255.1 239.60 100.00 0.00 silt/clay
322 306.5 127.92154 -27.921536
DESCRIPTION Silty SAND with some gravel
USCS SM
Prepared For: City of Renton Reviewed By: ELW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3" 2" 1" .75" .375" #4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Family First Community Center SAMPLE ID/TYPE B-5
PROJECT NO.2018-130 SAMPLE DEPTH 2.5 Feet
TECH/TEST DATE LC 5/28/2018 DATE RECEIVED 5/28/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)380.6 Weight Of Sample (gm)340.3
Wt Dry Soil & Tare (gm) (w2)340.3 Tare Weight (gm) 15.8
Weight of Tare (gm) (w3)15.8 (W6) Total Dry Weight (gm) 324.5
Weight of Water (gm) (w4=w1-w2) 40.3 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3) 324.5 Cumulative
Moisture Content (%) (w4/w5)*100 12 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.8 0.00 0.00 100.00 cobbles
% C GRAVEL 0.0 3.0"15.8 0.00 0.00 100.00 coarse gravel
% F GRAVEL 8.8 2.5" coarse gravel
% C SAND 5.2 2.0" coarse gravel
% M SAND 17.0 1.5"15.8 0.00 0.00 100.00 coarse gravel
% F SAND 37.9 1.0" coarse gravel
% FINES 31.2 0.75"15.8 0.00 0.00 100.00 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"22.3 6.50 2.00 98.00 fine gravel
D10 (mm)#4 44.3 28.50 8.78 91.22 coarse sand
D30 (mm)#10 61.2 45.40 13.99 86.01 medium sand
D60 (mm)#20 medium sand
Cu #40 116.3 100.50 30.97 69.03 fine sand
Cc #60 fine sand
#100 205.4 189.60 58.43 41.57 fine sand
#200 239.2 223.40 68.84 31.16 fines
PAN 340.3 324.50 100.00 0.00 silt/clay
322 306.2 94.360555 5.6394453
DESCRIPTION Silty SAND with trace gravel
USCS SM
Prepared For: City of Renton Reviewed By: ELW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3" 2" 1" .75" .375" #4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Family First Community Center SAMPLE ID/TYPE B-7
PROJECT NO.2018-130 SAMPLE DEPTH 5 Feet
TECH/TEST DATE LC 5/28/2018 DATE RECEIVED 5/28/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)712.1 Weight Of Sample (gm)618.1
Wt Dry Soil & Tare (gm) (w2)618.1 Tare Weight (gm) 15.7
Weight of Tare (gm) (w3)15.7 (W6) Total Dry Weight (gm) 602.4
Weight of Water (gm) (w4=w1-w2) 94.0 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3) 602.4 Cumulative
Moisture Content (%) (w4/w5)*100 16 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.7 0.00 0.00 100.00 cobbles
% C GRAVEL 4.6 3.0"15.7 0.00 0.00 100.00 coarse gravel
% F GRAVEL 19.5 2.5" coarse gravel
% C SAND 9.1 2.0" coarse gravel
% M SAND 13.6 1.5"15.7 0.00 0.00 100.00 coarse gravel
% F SAND 20.6 1.0" coarse gravel
% FINES 32.6 0.75"43.4 27.70 4.60 95.40 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"120.9 105.20 17.46 82.54 fine gravel
D10 (mm)#4 161.1 145.40 24.14 75.86 coarse sand
D30 (mm)#10 216.1 200.40 33.27 66.73 medium sand
D60 (mm)#20 medium sand
Cu #40 297.8 282.10 46.83 53.17 fine sand
Cc #60 fine sand
#100 387.2 371.50 61.67 38.33 fine sand
#200 421.9 406.20 67.43 32.57 fines
PAN 618.1 602.40 100.00 0.00 silt/clay
322 306.3 50.846614 49.1533865
DESCRIPTION Silty SAND with some gravel
USCS SM
Prepared For: City of Renton Reviewed By: ELW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3" 2" 1" .75" .375" #4 #10 #20 #40 #60 #100 #200
3 SaRT l
rl
t
TACorna . . < , ri E
Technica/Information Report
Y
i PREPARED FOR:
Greene-Gasaway Architects, PLLC
PO Box 4158
Federal Way, WA 98063-4158
PROJECT.•
Cascade Elementary School
16022 116th Avenue SE
Renton, WA 98058
Project No. 2140258.10
PREPARED BY.•
Rohin Elangovan, EIT
Project Engineer
REVIEWED BY.•
William J. Fierst, PE
Project Manager
Sean M. Comfort, PE
Principal
I DATE.•
June 2014
Revised July 2014
su 2 3 20
Civil Engineers • Structura!Engineers • Landscape Architects • Community Planners • Land Surveyors • lVeighbors
1 i
Technica/Information Report
PREPARED FOR:
Greene-Gasaway Architects, PLLC
PO Box 4158
Federal Way, WA 98063-4158
1ti4 CjI 1• O p PROJEGT.•
1
1 ,`:,6°rt "`8`,op
Cascade Elementary School
16022 116"' Avenue SE
Renton, WA 98058
O
o?+ ' Project No. 2140258.10
sloxsL
PREPARED BY.•
t hereby state tnat tnis Technical Rohin Elangovan, EIT
Information Report for Cascade
Elementary School has been prepared by Project Engineer
me or under my supervision, and meets
the standard of care and expertise that is REVIEWED BY.•usual and customary in this community
for professional engineers. I understand
that the City of Renton does not and will William ]. Fierst, PE
not assume liability for the suffiaency, Project Manager
suitability, or performance of drainage
facilities prepared by me.Sean M. Comfort, PE
Principal
DATE.•
une 2014
Revised July 2014
Tab/e of Content.s
Section Page
1.0 Project Overview............................................................................................................i
2.0 Conditions and Requirements Summary........................................................................i
2.1 Core Requirement 1 - Discharge at the Natural Location................................................i
2.2 Core Requirement 2 -Offsite Analysis ..........................................................................1
2.3 Core Requirement 3 - Flow Control ..............................................................................2
2.4 Core Requirement 4 - Conveyance System ...................................................................2
2.5 Core Requirement 5 - Erosion and Sediment Control.....................................................2
2.6 Core Requirement 6 - Maintenance and Operations.......................................................2
2.7 Core Requirement 7 - Financial Guarantees and Liability................................................2
2.8 Core Requirement 8 - Water Quality.............................................................................3
2.9 Special Requirement 1 - Other Adopted Requirements ..................................................3
2.10 Special Requirement 2 - Flood Hazard Delineation ........................................................3
2.11 Special Requirement 3 - Flood Protection Facilities........................................................3
2.12 Special Requirement 4 - Source Control........................................................................3
2.13 Special Requirement 5 - Oil Control..............................................................................3
2.14 Special Requirement 6 -Aquifer Protection Area...........................................................3
3.0 Offsite Analysis...............................................................................................................3
3.1 Task 1 - Study Area Definition and Maps......................................................................3
3.2 Task 2- Resource Review...........................................................................................4
3.3 Task 3 - Field Inspection.............................................................................................5
3.4 Task 4- Drainage System Description and Problem Descriptions...................................5
3.5 Quantitative Analysis...................................................................................................6
4.0 Flow Control and Water Quality Facility Analysis and Design .......................................6
5.0 Conveyance System Analysis and Design.......................................................................7
6.0 Special Reports and Studies...........................................................................................7
7.0 Other Permits.................................................................................................................7
8.0 CSWPPP Analysis and Design.........................................................................................7
9.0 Bond Quantities, Facility Summaries, and Dectaration of Covenant..............................8
10.0 Operations and Maintenance Manual.............................................................................8
11.0 Conclusion......................................................................................................................8
Technical Information Report O Q O OCascadeElementarySchool
Projed No. 2140258.10
Appendices
Appendix A
Technical Information Report(TIR) Worksheet
Exhibits
A-1 ...................Vicinity Map
A-2 ...................Soils Map
A-3 ...................Existing Conditions Plan
A-4...................Site Plan
A-5 ...................Existing Basin Map
A-6 ................... Developed Basin Map
A-7 ...................Site Flow Rates
A-8 ...................Conveyance Calculations
A-9 ...................Downstream Pipe Information
A-10 .................Aquifer Protection Area
A-11 .................King County iMAP Information
A-12 .................FIRM Rate Map
A-13 .................Renton Bond Quantiry Worksheet
A-14 .................Operations and Maintenance Manual
Appendix B
Cascade Elementary Topographic Map Prepared by Townsend-Chastain &Assoc.,Inc.
October 6, 1992
Cascade Elementary School Site Drainage Plan Prepared by RoseWater Engineering,
Inc.]une 14, 1994
Technical Information Report Q Q O QCascadeElementarySchool
Project No. 2140258.10
1.0 PRO]ECT OVERVIEW
Cascade Elementary School is located at 16022 116"' Avenue SE on Parcel No. 2823059034 in the
city of Renton. See Appendix A-1 for the Vicinity Map. The 2014 portable classroom project is
proposing to install two double portable classrooms, ramps, stairs, and landings at Cascade
Elementary School, and to demolish an existing single classroom por[able. See Appendix A-3 for
the Existing Conditions Plan and Appendix A-4 for the Site Plan. This would result in 3,436
square feet(SF) of new impervious surface and 19 SF of replaced impervious surface (total of
3,455 SF of new plus replaced impervious surfaces). In addition, 22 SF of impervious surface will
be converted to pervious lawn. The site will realize a net increase of 3,433 SF of impervious
surfaces. See Appendices A-5 and A-6 for Existing and Developed Basin Maps.
The 2009 King County Surface Water Design Manual(KCSWOM)and City ofRenton Amendments
to the King County Surface Water Design Manual(February 2010) establish the methodology and
design criteria used for the project. The King County Runoff Time Series (KCRTS) software
program, developed by the King County Department of Natural Resources, was used to calculate
runoff and design stormwater flow control facilities. The Rational method was used to determine
conveyance capacities.
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
The project triggers Full Drainage Review. Below is a summary of how the proposed project will
meet the Core Requirements.
2.1 Core Requirement 1 - Discharge at the Natural Location
The natural discharge location for stormwater from the work area is the yard drain north of the
existing double classroom portable, which connects via closed pipe to an existing catch basin
south of the existing double classroom portable. Stormwater in the existing catch basin is
conveyed east and south around the Cascade Elementary School building and through the site to
the southeast corner of the site. Stormwater is then conveyed east through a residential area in
an 18-inch concrete pipe toward 119"'Avenue SE.
Stormwater roof runoff from the new portables will be discharged from the roof with
downspouts, and will flow to a series of proposed catch between the two proposed double
classroom portables. The proposed conveyance pipes convey stormwater to a proposed catch
basin overbuilt on the existing drainage system. The existing drainage pipes convey stormwater
to an existing catch basin south of the existing double classroom portable. Drainage is routed
downstream through the existing conveyance system onsite. All surface and stormwater runoff
from the proposed development will continue to be discharged at the natural location, and thus
will not adversely affect downstream properties or drainage systems.
2.2 Core Requirement 2 - Offsite Analysis
AHBL staff performed a Level One Downstream Analysis for the project on June 11, 2014, and
July 17, 2014. The analysis included:
Defining and mapping the study area.
Reviewing available information on the study area.
Technical Information Report Q Q 0 OCascadeElementarySchool1
Project No. 2140258.10
Field inspecting the study area.
Analyzing the existing drainage system, including its existing and predicted problems, if
any.
Please refer to Sedion 3.0 for the full offsite analysis.
2.3 Core Requirement 3 - Flow Control
The project site lies in the Flow Control Duration Standard Area, per the King County Flow
Control Application Map of the 2009 KCSWDM. This project meets Exception 2 for Flow Control
Duration Standard Area because the project proposes no more than a 0.1-cfs difference in the
sum of developed 100-year peak flows for target surfaces subject to this requirement, and the
sum of forested site conditions 100-year peak flows for the same surface areas. See
Appendix A-7 for pre-and post-developed peak flow rates.
2.4 Core Requirement 4 - Conveyance System
The two new double portable classrooms will include downspouts that tie into a roof drain system
prior to entering proposed catch basins onsite. Based on Section 1.2.4.1 of the KCSWDM, new
pipe systems shall be designed with sufficient capacity to convey and contain the 25-year peak
flow with a minimum of 6 inches of freeboard between the design water surFace and structure
grate. In addition, runoff from the 100-year peak storm event cannot create or aggravate a
severe flooding problem or severe erosion problem. The new pipe system has sufficient capacity
for a 25-year peak flow. Catch basin rims do not overtop in the 100-year peak storm event and
there is over a 6-inch freeboard between the design water surface and structure grate during the
25-year peak storm event. No severe flooding problems or severe erosion problems are created
or aggravated in the 100-year storm event. A quantitative downstream analysis was completed.
See Appendix A-8 for the conveyance basin and calculations, and downstream analysis.
2.5 Core Requirement 5 - Erosion and Sediment Control
Onsite land disturbance will be very minimal and will consist of clearing the work site
approximately 7,500 SF), small amounts of demolition, and regrading for placement of two catch
basins. Erosion and sediment control will be provided with the use of temporary and permanent
seeding within the work limits, silt fence or wattles, and inlet sediment protection. A Temporary
Erosion and Sedimentation Control Plan is included in the plan set. See Section 8.0 for CSWPPP
Analysis and Designs.
2.6 Core Requirement 6 - Maintenance and Operations
Maintenance and operation of all drainage facilities will be maintained by the owner. The project
proposes new catch basins onsite. See Appendix A-14 for the Operations and Maintenance
Manual.
2.7 Core Requirement 7 - Financial Guarantees and Liability
This project will provide financial guarantees and liability per City of Renton requirements. See
Appendix A-13 for the Renton Bond Quantity Worksheet.
Technical Information Report O Q O OCascadeElementarySchool2
Project No. 2140258.10
i
2.8 Core Requirement 8 - Water Quality
No pollution generating surfaces are proposed as part of this development; therefore, the
development meets the Surface Area Exemption. Core Requirement 8 will not apply.
2.9 Special Requirement 1 - Other Adopted Requirements
The project is include in the Lower Cedar River Drainage Basin. City and County basin
requirements will be followed where applicable.
2.10 Special Requirement 2 - Flood Hazard Delineation
The proposed project is not in or adjacent to the 100-year floodplain. See Appendix A-12 for the
FIRM Rate Map.
2.i i Special Requirement 3 - Flood Protection Facilities
This project does not rely on existing flood protection facilities, nor will it modify or construct new
flood protection facilities.
2.12 Special Requirement 4 - Source Control
The proposed project is an educational facility; therefore, it does not t the definition of a
commercial, industrial, or multi-family site for source control purposes.
2.13 Special Requirement 5 - Oil Control
The site does not meet high use criteria and is not subject to oil control measures.
2.14 Special Requirement 6—Aquifer Protection Area
According to the City of Renton Aquifer Protection Zone Map, the project is not located within an
aquifer protection zone. See Appendix A-10 for a map of the Aquifer Protection Area.
3.0 OFFSITE ANALYSIS
There are no upstream tributary areas contributing drainage to the basin area.
3.1 Task i — Study Area Definition and Maps
Cascade Elementary School proposes to place two new portable buildings on the 14.88-acre site
located at 16022 116'Ave SE in the city of Renton. Based on a site visit on July 17, 2014, the
upstream basins that flow onsite were delineated and can be found in Appendix A-8.
The project site lies within the Lower Cedar River Drainage Basin, as delineated by the King
County Water Features Map. There are no wetlands on or in the vicinity of the project site.
The project receives upstream stormwater from two separate basins. One basin includes the
western half of the elementary school building, the parking lot to the west of the elementary
school building, a portion of 116"' Avenue SE, and a residential area to the west of 116th Avenue
SE. This basin includes 3.297 acres of impervious area and 2.676 acres of pervious area. This
Technical Information Report O Q O QCascadeElementarySchool3
Project No. 2140258.10
basin conveys to a manhole directly southeast of Cascade Elementary School in a 12-inch
concrete pipe. The second basin includes a larger portion of 116"' Avenue SE and SE 162nd
Street, and a residential area to the west of 116 h Avenue SE. This basin includes 3.140 acres of
impervious area and 3.439 acres of pervious area. This basin conveys stormwater through a
biofiltration swale to the south of the project site before conveying to a manhole to the east of
the biofiltration swale. The basins were delineated using City of Renton COR Maps and a field
inspection described in Task 3.
In existing conditions, there is one discharge location from the project site. Stormwater from the
site flows to a yard drain onsite. Flow travels from this yard drain through a series of closed
storm drain catch basins to the southeast corner of the site. Stormwater from the field to the
east of Cascade Elementary School is mllected in an underdrain system and conveyed to the
catch basin on the southeast corner of the project site, prior to discharging offsite to the east
toward 119th Avenue SE. See Appendix A-9 for a sketch of the downstream conveyance system.
3.2 Task 2— Resource Review
The following resources were reviewed to discover any existing or potential problems in the study
area:
Topographic Survey: Cascade Elementary Topographic Survey prepared by Townsend-
Chastain &Assoc., Inc., October 6, 1992, included in Appendix B.
Civil Engineering Plans: Cascade Elementary School Site Drainage Plan prepared by
RoseWater Engineering, Inc., June 14, 1994, included in Appendix B.
Landscape Plans: Cascade Elementary School Pla eld Grading and Sub-Drainage Plan
prepared by Don Shimono Associates, included in Appendix A-8.
FEMA Map: FEMA Flood Insurance Rate Map 53033C0983F, dated May 16, 1995, (see
Exhibit A-12) indicates that the project site lies within Zone X—Areas determined to be
outside the 500-year floodplain. -I
King County iMAP: The project site is not located in any of the following mapped critical
areas (see Exhibit A-11):
o Coal Mine Hazard Areas
o Erosion Hazard Areas
o Landslide Hazard Areas
o Seismic Hazard Areas
o Critical Aquifer Recharge Areas
0 100-Year Flood Plain
o Wetlands
Soils Information: Site soils have been classified by the USDA Natural Resources
Conservation Service(NRCS) as Arents, Alderwood material, 6 to 15 percent slopes (AmC)
see Exhibit A-2).
City of Renton COR Maps: The upstream and downstream basins were delineated I
utilizing City of Renton COR Maps, along with a site visit on July 17, 2014.
Technical Information Report O Q O 0CascadeElementarySchool4
Project No. 2140258.10
3.3 Task 3 — Field Inspection
On June 11, 2014, and July 17, 2014, AHBL staff performed a downstream analysis of the
drainage system receiving stormwater runoff from the proposed portable classrooms, and an
upstream analysis of the drainage system discharging to piping at Cascade Elementary School.
1. Investigate any problems reported or observed during the resource review— No problems
were reported or observed during the resource review.
2. Locate all existing/potential constrictions or lack of capacity in the existing drainage system
No constrictions or lack of capacity in the existing drainage system was obseroed.
3. Identify all existing/potential downstream drainage problems as defined in Section 1.2.2.1
No existing/potential downstream drainage problems were observed.
4. Identify existing/potential overtopping, scouring, bank sloughing, or sedimentation — No
existing/potential overtopping, scouring, bank sloughing, or sedimentation was observed.
5. Identify significant destruction of aquatic habitat or organisms (e.g., severe siltation, back
erosion, or incision in a stream)— No significant destruction of aquatic habitat or organisms
was observed.
6. Collect qualitative data on features such as land use, impervious surfaces, topography, and
soil types —The land use on the project site is a school site that consists of approximately
30 percent impervious area and sports fields to the south end. The conveyance system
drains through a residential area to the east before reaching 119"'Avenue SE, where the
road slopes down to a catch basin before being conveyed farther east. The upstream
basin was delineated by determining where the road slopes toward the site and following
the piping onsite, along with the contours found in City of Renton COR Maps.
7. Collect information on pipe sizes, channel characteristics, drainage structures, and relevant
critical areas (e.g., wetlands, stream, steep slopes) — See Appendix A-9 for information on
pipe sizes and drainage structures. No critical areas were observed.
8. Verify tributary basins delineated in Task 1 — Based on the topography onsite, the basin
delineation based on the survey was confirmed.
9. Contact neighboring property owners or residents in the area about past or existing
drainage problems, and describe these in the report (optional) —This requirement is not
applicable for this project.
10. Note the date and weather conditions at the time of the inspection —The first site visit
occurred on June 11, 2014. The weather was sunny and the temperature was 60 degrees.
The second site visit occurred on July 17, 2014. The weather was sunny and the
temperature was 73 degrees.
3.4 Task 4— Drainage System Description and Problem Descriptions
See Appendix A-9 for a map of the downstream drainage system. The existing point of discharge
for the portables basin is an existing yard drain onsite. This yard drain is being demolished as
part of this project. Three new catch basins and conveyance piping are proposed between the
two proposed double classroom portables. Stormwater will flow from the proposed portables to
Technical Information Report Q Q O OCascadeElementarySchool5
Project No.2140258.10
catch basins via roof drain and closed conveyance piping. A new catch basin will be overbuilt on
the existing drainage system. Downstream of the overbuilt catch basin, stormwater is conveyed
to an existing catch basin south of the existing double classroom portable onsite. Stormwater
outfalling from the catch basin flows east approximately 154 feet in an 8-inch concrete pipe along
the building perimeter to a solid-lid catch basin to the northeast of the school building.
Stormwater is conveyed south in 15-inch conc ete pipe through a series of three solid-lid catch
basins approximately 615 feet to a catch basin just east of the storm facility onsite. Stormwater
is conveyed in a 15-inch concrete pipe approximately 390 feet east to a catch basin on the
southeast corner of the project site. Stormwater is conveyed in an 18-inch concrete pipe
210 feet to a catch basin on the east side of 119"' Avenue SE. Based on the City of Renton GIS
Mapping System, stormwater is then conveyed in a 24-inch concrete pipe east through a
residential area toward Cascade Park, where the conveyance system ties into an existing 36-inch
storm main system.
No signs of flooding, overtopping, or erosion were evident at the time of the inspection.
3.5 Quantitative Analysis
A quantitative analysis modeling the downstream drainage to the east properly line of the project
system under existing and proposed conditions was performed at the request of the City of
Renton. The analysis was completed using the StormSHED2G program and the Rational Method.
The analysis determines that during the 25-year, 24-hour peak storm event, all pipes have
adequate capacity and all catch basins and manholes have a minimum of 6 inches of freeboard
between the design water surface and structure grate. In the 100-year peak storm event, catch
basins do not overtop and no severe flooding problems or severe erosion problems are created or
aggravated. Downstream basin conveyance calculations, including basin delineation and
StormSHED2G outputs, can be found in Appendix A-8.
The RoseWater Engineering Inc. and Don Shimano Associates plans included as part of the
quantitative analysis in Appendix A-8 were on a different datum than the AHBL Civil Plans.
Therefore, a conversion factor of+3.11 feet was applied to each of the rims and inverts on these
plans to match the AHBL datum.
As required, all storm drainage structures have in excess of 6 inches of freeboard between the
computed hydraulic grade and rim elevation during the 25-year peak storm event.
4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
The project proposes an increase of no more than a 0.1-cfs difference in the sum of developed
100-year peak flows for target su faces subject to this requirement and the sum of forested site
conditions 100-year peak flows for the same surface areas, which exempts the project from flow
control requirements per Exception 2 in Section 1.2.3.1(B) of the 2009 KCSWDM. The existing
impervious surface beneath the portable to be removed from the site is to be protected and not
disturbed; therefore, the existing impervious surface beneath the portable is not a replaced
impervious surface and is not considered a target surface. The sidewalk beneath the proposed
double classroom portable to the north is to be protected and not disturbed; therefore, it is not a
replaced impervious surface and is not considered a target surFace. The basin was modeled
using KCRTS per the fallowing conditions:
Technical InfoRnation Report 0 Q O OCascadeElementarySchool6
Project No. 2140258.10
Pre-Develo ed ac Post-Develo ed ac
Forest 0.0710 0
Lawn 0.0810 0.0816
Im rvious 0.0816 0.1520
Total 0.2336 0.2336
100- ear Peak Flow cfs
Pre-develo d 0.188
Post-develo ed 0.274
The increase in the 100-year peak flow rate is 0.086 cfs, which is less than the 0.1 cfs threshold.
Detailed calculaaons to demonstrate exemption from flow control have been included in
Appendix A-7.
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
The project proposes collection of storm drainage from the two proposed double classroom
portables by roof drain systems that drain to proposed catch basins between the two proposed
classroom portables and to the downstream drainage system. Conveyance capacity calculations
are included in Appendix A-8.
G.O SPECIAL REPORTS AND STUDIES
There are no special reports or studies necessary for the proposed project.
7.0 OTHER PERMITS
No other permits are required as part of this proposed development.
8.O CSWPPP ANALYSIS AND DESIGN
The proposed development shall comply with guidelines set forth in City of Renton drainage
requirements. The plan will include erosion/sedimentation control features designed to prevent
sediment-laden runoff from leaving the site or adversely affecting critical water resources during
construction.
The following measures are shown on the ESC plans and will be used to control
sedimentation/erosion processes:
Clearing Limits—All areas to remain undisturbed during the construction of the project will
be delineated prior to any site clearing or grading.
Cover Measures—Cover measures will be implemented to the disturbed areas.
Perimeter Protection — Filter fabric fences for site runoff protection will be provided at the
downstream site perimeter.
Traffic Area Stabilization —Traffic Area Stabilization is not applicable for this project
Sediment Retention—Inlet sediment protection will be utilized as part of this project.
Technical Information Report O Q O OCascadeElementarySchool7
Project No. 2140258.10
Storm Drain Inlet Protection—Inlet sediment protection will be provided on all new and
existing catch basins downstream of construction activities.
Surface Water Collection —Catch basins and conveyance pipes will provide surface water
collection.
Dewatering Control —Dewatering Control is not applicable for this project.
Dust Control —Dust control measures including sweeping and water truck will be
implemented when exposed soils are dry to the point that wind transport is possible, and
roadways, drainage ways, or surface waters are likely to be impacted.
Flow Control— Flow Control is not applicable for this project.
9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
See Section 2.7 above for Core Requirement 7, Financial Guarantees and Liability. See
Appendix A-13 for the City of Renton Bond Quantity Worksheet. Facility Summaries and a
Declaration of Covenant are not applicable to this project. I
10.0 OPERATIONS AND MAINTENANCE MANUAL
II
Maintenance and operation of all drainage facilities will be maintained by the owner. The project
proposes new catch basins onsite. See Appendix A-14 for operations and maintenance
information.
11.0 CONCLUSION
This site has been designed to meet or exceed the requirements of the 2009 King County
Surface Water Design Manual(KCSWDM), as amended by the City of Renton Amendments to the
King County Surface Water Design Manua/(February 2010). Flow calculations and modeling
utilize City of Renton standards for sizing stormwater conveyance.
This analysis is based on data and records either supplied to or obtained by AHBL. These documents are
referenced within the text of the analysis. The analysis has been prepared using procedures and
practices within the standard accepted practices of the industry.
AHBL, Inc.
Rohin Elangovan, EIT
Project Engineer
RE/Isk
June 2014
Revised July 2014
Q:12014 2140258 WORDPROC Reports 20140724_Rpt_(TiR)_2140258.10(wp dreft).doac
Technical Information Report Q Q O aCascadeElementarySchool8
Project No. 2140258.10
Appendix A
Technical Information Report (TIR) Worksheet
Exhibits
A-i ..................Vicinity Map
A-2 ..................Soils Map
A-3 ..................Existing Conditions Plan
A-4 ..................Site Plan
A-5 ..................Existing Basin Map
A-6 ..................Developed Basin Map
A-7 ..................Site Flow Rates
A-8 ..................Conveyance Calculations
A-9 ..................Downstream Pipe Information
A-10.................Aquifer Protection Area
A-11.................King County iMAP Information
A-12.................FIRM Rate Map
A-13.................Renton Bond Quantity Worksheet
A-14.................Operations and Maintenance Manual
Technical Infomiation Report O Q O OCascadeElementarySchool
Project No. 2140258.10
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND
PROJECT ENGINEER DESCRIPTlON
ProjectOwner F 7'°" 5«t-oo D\Sl2r ProjectName CAScRD E 6'Er T.Y
Phone '2 S 2 nH-N v o 3 DDES Permit#
Address 7 ft 2 5 2yT" Sr, S-6-, Location Township ?3
l/ 'l7 Range O
Project Engineer wl i''r hf Sj Section 2
Company 1 F`Site Address 6 ZZ //6r" A E Sr,
Phone Cy53 3 3 'Zy2 Ta N WA- Q go5
Pa#3 TYPE OF PERM(T APPLICATION Part 4 OTHER REVIEWS AND PERMITS
Landuse Services DFW HPA Shoreline
Subdivison / Short Subd. / IPD ManagementCOE404
Building Services DOE Dam Safety Structural
M/F/Commerical / SFR RockeryNault/
Clearing and Grading
FEMA Floodplain ESA Section 7
Right-of-Way Use COE Wetlands
Other Other
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review Ful / Targeted / Type (circle one}: Fu / Modified /
circle): Large Site Small Site
Date (include revision Date (include revision
dates): dates):
Date of Final: Date of FinaL•
Part 6 ADJUSTMENT APPROVALS
Type (circle one): Standard ! Complex / Preapplication / Experimental! Blanket N(f
Description: (include conditions in TIR Section 2)
NIA-
Date of A roval:
i --
2009 Surface Water Design Manual 1/9/2009
1
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 7 MONITORING REQUlREMENTS
Describe: N I RMonitoringRequired: Yes / Io
Start Date:t
Completion Date:R
Part 8 SfTE COMMUNITY AND DRAINAGE BASIN
Community Plan : Soos CRCEk
Special District Overlays:
Drainage Basin: D+n r`.. EDAR (v.2 1
Stormwater Requirements:
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
River/Stream Steep Slope
Lake Erosion Hazard
Wetlands Landslide Hazard
I
Closed Depression Coal Mine Hazard
Floodplain Seismic Hazard
Other ('( Habitat Protection
Part 10 SOILS
Soil Type Slopes Erosion Potential
A, 5% op qr%-.F
High Groundwater Table (within 5 feet) Sole Source Aquifer
Other( Seeps/Springs
Additional Sheets Attached
2009 Surface Water Design Manual 1/9/2009
2
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 11 DRAINAGE DESIGN LIMITATIONS
I
REFERENCE LIMITATION/SITE CONSTRAINT
Core 2—Offsite Analvsis
Sensitive/Critical Areas
SEPA
Other
N C
Additional Sheets Attached
Part 12 TIR SUMMARY SHEET rovide one TIR Summa Sheet er Threshold Dischar e Area
Threshold Discharge Area:
name or descri tion Sc t u n F
Core Requirements (all 8 apply)
Dischar e at Natural Location Number o atural Dischar e Locations: I I
Offsite Analysis Level: 1 / 2 / 3 dated:T 1
Flow Control Level: 1 / / 3 or Exemption Number Ex crn,N
incl.facili summa sheet Small Site BMPs
Conveyance System Spill containment located at:
Erosion and Sediment Control ESC Site Supervisor: TT3 D, a+c,r P aContactPhone:
W After Hours Phone:
Maintenance and Operation Responsibility: Private ublic
If Private, Maintenance Lo Re uired: Yes !No
Financial Guarantees and Provided: es / No
Liabili
Water Quality Type: Basic / Sens. Lake / Enhanced Basicm / Bog
include facility summary sheet} or Exemption No. I
Landsca e Mana ement Plan: Yes / No
S ecial Re uirements as a licable
Area Specific Drainage Type: CDA/SDO/MDP/BP/LMP/Shared Fac.I None
Re uirements Name:
Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 1 R
100-year Base Flood Elevation (or range):
Datum:
Flood Protection Facilities Describe:
Source Control Describe landuse:
comm./industrial landuse)Describe any structural controls: (
2009 Surface Water Design Manual 1/9/2009
3 I
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Oii Control High-use Site: Yes /
Treatment BMP:
Maintenance Agreement: Yes /'Vo
with whom?
Other Draina e Structures
Describe: C- 6aS 5 $.. G oSe,, G'Qv V2 ct/v(2._ PZ-
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION AFTER CONSTRUCTION
Clearing Limits Stabilize Exposed Surfaces
Cover Measures Remove and Restore Temporary ESC Facilities
Perimeter Protection Clean and Remove All Silt and Debris, Ensure
Traffic Area Stabilization Operation of Permanent Facilities
Sediment Retention Flag Limits of SAO and open space
preseroation areas
Surface Water Collection Other
Dewatering Control
Dust Control
Flow Control
Part 14 STORMWATER FACILITY DESCRIPTIONS Note: Include Facili Summa and Sketch
Flow Control T e/Descri tion Water Quali T e/Descri tion
Detention Biofiltration v
Infiltration Wetpool
Regional Facility Media Filtration
Shared Facility Oil Control
Flow Control Spill Control
BMPs
Flow Control BMPs
Other
Other
2009 Surface Water Design Manual 1/9/2009
4
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 15 EASEMENTSiTRACTS Part 16 STRUCTURAL ANALYSIS
Drainage Easement Cast in Place Vault
Covenant Retaining Wall
Native Growth Protection Covenant Rockery>4' High I
Tract Structural on Steep Slope
Other Other
Part 17 SIGNATURE OF PROFESSIONAL ENGINEER
I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were
incorporated into this worksheet and the attached Technical Information Report. To the best of my
knowledge the information provided here is accurate.
1 a ao
Si ned/Date
2009 Surface Water Design Manual 1/9/2009
5
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Custom Soil Resource Report
MAP LEGEND MAP INFORMATION
Area of interest(AOq Spoil Area The soil surveys that comprise your AOI were mapped at 1:24,000.
Area oflnterest(AOI) Stony Spot
Sons Very Stony Spot Warning:Soil Map may not be valid at this scale.
Soil Map Unit Polygons
wet Spot Enlargement of maps beyond the scale of mapping can cause
N Soil Map Unit Lines
Other I misunderstanding of the detail of mapping and accuracy of soil line
Soii Map unit Points placement.The maps do not show the small areas of contrasting
Special Line Features soils that could have been shown at a more detailed scale.
Special Point Features
Blowout Water Features
Streams and Canals Please rely on the bar scale on each map sheet for map
eorrow Pit measurements.
Transportation
Clay Spot Rails Source of Map: Natural Resources Conservation Service
Closed Depression interscate Highways Web Soil Survey URL: http://websoilsurvey.nres.usda.gov
Gravel Pit US Routes
Coordinate System: Web Mercator(EPSG3857)
Graveny Spot Major Roads Maps from the Web Soil Survey are based on the Web Mercator
Landfill Local Roads projection,which preserves direction and shape but distorts
distance and area.A projection that preserves area,such as the
Lava Flow eackground Albers equal-area conic projection,should be used if more accurate
Marsh or swamp Aerial Photograpny calculations of distance or area are required.
nnine or Quarry This product is generated from the USDA-NRCS certified data as of
o Misceuaneous Water the version date(s)listed below.
Perennial Water
Soil Survey Area: King County Area,Washington
Rock outcrop Survey Area Data: Version 8,Dec 10,2013
Saline Spot
Soil map units are labeled(as space allows)for map scales 1:50,000
Sandy Spot of lafgef.
Severely Eroded Spot
Date(s)aerial images were photographed: Aug 31,2013—Oct 6,
Sinkhole 2013
Slide or Slip
The orthophoto or other base map on which the soil lines wereSodicSpotcompiledanddigitizedprobablydiffersfromthebackground
imagery displayed on these maps.As a result,some minor shifting
9 A-2
Custom Soil Resource Report
Map Unit Legend
King County Area,Washington(WA633)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
AmC Arents,Alderwood material,6 to 2.5 100.0%
15 percent slopes
Totals for Area of Interest 2D.5 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the soils
or miscellaneous areas in the survey area. The map unit descriptions, along with the
maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils.On the landscape,
however,the soils are natural phenomena, and they have the characteristic variability
of all natural phenomena. Thus, the range of some observed properties may extend
beyond the limits defined for a taxonomic class.Areas of soils of a single taxonomic
class rarely, if ever, can be mapped without including areas of other taxonomic
classes. Consequently, every map unit is made up of the soils or miscellaneous areas
for which it is named and some minor components that belong to taxonomic classes
other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
mana ement.These are called contrastin or dissimilar com onents.The enerall99 P Y 9 Y
are in small areas and could not be mapped separately because of the scale used.
Some small areas of strongly contrasting soils or miscellaneous areas are identified
by a special symbol on the maps. If included in the database for a given area, the
contrasting minor components are identified in the map unit descriptions along with
some characteristics of each.A few areas of minor components may not have been
observed, and consequently they are not mentioned in the descriptions, especially
where the pattern was so complex that it was impractical to make enough observations
to identify all the soils and miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the usefulness
or accuracy of the data. The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into landforms or landform segments that
i
have similar use and management requirements. The delineation of such segments
on the map provides sufficient information for the development of resource plans. If
intensive use of small areas is planned, however, onsite investigation is needed to
define and locate the soils and miscellaneous areas.
o A_2
II
Custom Soil Resource Report
An identifying symbol precedes the map unit name in the map unit descriptions. Each
description includes general facts about the unit and gives important soil properties
and qualities.
Soils that have profiles that are almost alike make up a soi!series. Except for
differences in texture of the surface layer, all the soils of a series have major horizons
that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surFace layer, slope, stoniness, salinity,
degree of erosion, and other characteristics that affect their use. On the basis of such
differences, a soil series is divided into soil phases. Most of the areas shown on the
detailed soil maps are phases of soil series. The name of a soil phase commonly
indicates a feature that affects use or management. For example, Alpha silt loam, 0
to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.The
pattern and proportion of the soils or miscellaneous areas are somewhat similar in all
areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present or
anticipated uses of the map units in the survey area, it was not considered practical
or necessary to map the soils or miscellaneous areas separately. The pattern and
relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-
Beta association, 0 to 2 percent slopes, is an example.
An undifferentiafed group is made up of two or more soils or miscellaneous areas that
could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion of
the soils or miscellaneous areas in a mapped area are not uniform. An area can be
made up of only one of the major soils or miscellaneous areas, or it can be made up
of all of them.Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include misce!laneous areas. Such areas have little or no soil material
and support little or no vegetation. Rock outcrop is an example.
11
A-2
Custom Soil Resource Report
King County Area, Washington
AmC—Arents, Alderwood material, 6 to 15 percent slopes
Map Unit Setting
Mean annual precipitation: 35 to 60 inches
Mean annual air temperature: 50 degrees F
Frost-free period: 150 to 200 days
Map Unit Composition
Arents, alderwood material, and similar soils: 100 percent
Description of Arents,Alderwood Material
Setting
Landform: Till plains
Parent material: Basal till
Typical profile
H1 -0 to 26 inches: moderately acid, gravelly sandy loam
H2-26 to 60 inches: moderately acid, very gravelly sandy loam
Properties and qualities
Slope: 6 to 15 percent
Depth to restrictive feature: 20 to 40 inches to densic material
Natural drainage class: Moderately well drained
Capacity of the most limiting layer to transmit water(Ksat): Very low to moderately
low(0.00 to 0.06 in/hr)
Depth to water table: About 16 to 36 inches
Frequency of flooding: None
Frequency of ponding: None
Available waterstorage in profile: Very low(about 2.3 inches)
Interpretive groups
Farmland classification: Not prime farmland
Land capability classification(irrigated): None specified
Land capability classification(nonirrigated): 4s
Hydrologic Soil Group: B/D
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Flow Frequency Analysis LogPearson III Coefficients
Time Series File:predev.tsf Mean= -1.307 StdDev= 0.173
Project Location:Sea-Tac Skew= 1.543
Annual Peak Flow Rates--- Flow Frequency Analysis-------
Flow Rate Rank Time of Peak Peaks - - Rank Return Prob
CFS)CFS) Period
0.071 9 2/16/49 17:45 0.226 1 89.50 0.989
0.101 4 3/03/50 15:00 0.119 2 32.13 0.969
0.038 37 8/27/51 18:00 0.105 3 19.58 0. 949
0.046 27 10/17/51 7:15 0. 101 4 14.08 0.929
0.033 45 9/30/53 3:00 0. 098 5 10.99 0.909
0.039 35 12/19/53 17:30 0. 076 6 9.01 0.889
0 .032 46 11/25/54 1:00 0.075 7 7 .64 0.869
0 .047 25 10/04/55 10:00 0.074 8 6.63 0.849
0 .049 19 12/09/56 12:45 0.071 9 5.86 0.829
0.044 32 1/16/58 10:00 0.058 10 5.24 0.809
0.054 14 10/18/58 19:45 0.057 11 4.75 0.789
0.056 12 10/10/59 22:00 0.056 12 4.34 0.769
0.049 20 2/14/61 20:15 0.056 13 3 .99 0.749
0.038 39 8/04/62 13:15 0.054 14 3 .70 0.729
0. 039 36 12/01/62 20:15 0.052 15 3 .44 0.709
0.029 49 6/05/64 15:00 0.051 16 3 .22 0.690
0.046 28 4/20/65 19:30 0.051 17 3. 03 0.670
0.030 48 1/05/66 15:00 0.050 18 2. 85 0.650
0.051 16 11/13/66 17:45 0.049 19 2.70 0.630
0.105 3 8/24/68 15:00 0.049 20 2. 56 0 .610
0.046 29 10/20/68 12:00 0.049 21 2.44 0 .590
0.028 50 1/13/70 20:45 0.049 22 2.32 0 .570
0.034 43 12/06/70 7:00 0.048 23 2.22 0 .550
0.074 8 12/08/71 17 :15 0.047 24 2.13 0.530
0.038 38 4/18/73 9:30 0. 047 25 2.04 0.510
0 .048 23 11/28/73 8:00 0. 047 26 1.96 0.490
0 .049 22 8/17/75 23 :00 0. 046 27 1.89 0.470
iij 0 .035 42 10/29/75 7:00 0. 046 28 1.82 0.450
0.031 47 8/23/77 14:30 0. 046 29 1.75 0.430
0.056 13 9/17/78 1:00 0. 045 30 1.70 0.410
0.076 6 9/08/79 13:45 0.045 31 1.64 0.390
0.058 10 12/14/79 20:00 0.044 32 1.59 0.370
0. 051 17 9/21/81 8:00 0.042 33 1.54 0.350
0.119 2 10/05/81 22:15 0.040 34 1.49 0.330
0.047 26 10/28/82 16:00 0.039 35 1.45 0.310
0.037 40 1/02/84 23:45 0.039 36 1.41 0.291
0.033 44 6/06/85 21:15 0.038 37 1 .37 0.271
0.050 18 10/27/85 10:45 0.038 38 1.33 0.251
0.057 11 10/25/86 22:45 0.038 39 1.30 0.231
0.045 30 5/13/88 17:30 0.037 40 1.27 0.211
0.042 33 8/21/89 16:00 0.037 41 1.24 0.191
0.075 7 1/09/90 5:30 0.035 42 1.21 0.171
0.049 21 4/03/91 20:15 0.034 43 1.18 0.151
0.037 41 1/27/92 15:00 0.033 44 1.15 0.131
0 .045 31 6/09/93 12:15 0.033 45 1.12 0.111
0 .040 34 11/17/93 16:45 0 .032 46 1. 10 0.091
0 .047 24 6/05/95 17 :00 0 .031 47 1 . 08 0 .071
A-7
0 .052 15 5/19/96 11 :30 0.030 48 1.05 0 . 051
0 .226 1 12/29/96 11:45 0.029 49 1.03 0.031
0 .098 5 10/04/97 14:15 0.028 50 1.01 0 .011
Com ute Pea s
Computed Peaks 0.148 50. 00 0 .980
Computed Peaks i 0.116 25.00 0 .960
Computed Peaks 0. 084 10.00 0 .900
Computed Peaks 0. 079 8.00 0 .875
Computed Peaks 0. 065 5.00 0.800
Computed Peaks 0.045 2.00 0.500
Computed Peaks 0.036 1.30 0.231
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A-7
Flow Frequency Analysis LogPearson III Coefficients
Time Series File:mitigated.tsf Mean= -1. 072 StdDev= 0. 158
Project Location:Sea-Tac Skew= 1.326
Annual Peak Flow Rates--- Flow Frequency Analysis-------
Flow Rate Rank Time of Peak Peaks - - Rank Return Prob
CFS)CFS) Period
0.115 8 2/16/49 17:45 0.315 1 89.50 0 .989
0.151 5 3/03/50 15:00 0. 195 2 32. 13 0.969
0.071 35 8/27/51 18:00 0.176 3 19. 58 0.949
0.080 25 10/17/51 7:15 0.157 4 14.08 0.929
0.060 43 9/30/53 3:00 0.151 5 10.99 0.909
0.066 38 12/19/53 17:30 0.139 6 9. 01 0.889
0.058 45 7/30/55 21:15 0.117 7 7.64 0.869
0.088 18 10/04/55 10:00 0.115 8 6.63 0.849
0.078 29 12/09/56 12:45 0.111 9 5.86 0.829
0.074 33 1/16/58 10:00 0.102 10 5.24 0.809
0.096 12 10/18/58 19:45 0.100 11 4.75 0.789
0.095 13 10/10/59 22 :00 0. 096 12 4.34 0.769
0.079 26 2/14/61 20:15 0.095 13 3.99 0.749
0.070 36 8/04/62 13:15 0.094 14 3.70 0.729
0.066 39 12/01/62 20:15 0.094 15 3 .44 0.709
0 .053 48 6/OS/64 15:00 0.092 16 3 .22 0.690
0 .074 32 4/20/65 19:30 0.091 17 3.03 0 .670
0. 051 49 1/05/66 15:00 0.088 18 2.85 0.650
0. 087 19 11/13/66 17:45 0.087 19 2.70 0.630
0.176 3 8/24/68 15:00 0 .087 20 2.56 0.610
0.078 28 10/20/68 12:00 0. 087 21 2.44 0.590
0.047 50 1/13/70 20:45 0. 083 22 2 .32 0.570
0.057 47 12/06/70 7:00 0.082 23 2 .22 0.550
0.117 7 12/08/71 17:15 0.081 24 2.13 0.530
0.069 37 4/18/73 9:30 0.080 25 2.04 0.510
0.081 24 11/28/73 8:00 0.079 26 1 .96 0.490
0.091 17 8/17/75 23:00 0.079 27 1.89 0.470
0.060 42 10/29/75 7:00 0.078 28 1. 82 0.450
0.057 46 8/23/77 14:30 0.078 29 1.75 0.430
0.100 11 9/17/78 1:00 0.078 30 1.70 0.410
0.139 6 9/08/79 13:45 0.075 31 1.64 0.390
0. 094 15 12/14/79 20:00 0. 074 32 1.59 0.370
0. 094 14 9/21/81 8:00 0.074 33 1.54 0.350
0.195 2 10/05/81 22:15 0.074 34 1.49 0.330
0.082 23 10/28/82 16:00 0.071 35 1.45 0.310
0.063 40 1/02/84 23:30 0.070 36 1.41 0.291
0.059 44 6/06/85 21:15 0.069 37 1.37 0.271
0.087 20 10/27/85 10:45 0.066 38 1.33 0.251
0.102 10 10/25/86 22:45 0.066 39 1.30 0.231
0.083 22 5/13/88 17:30 0.063 40 1.27 0.211
0.078 30 8/21/89 16:00 0. 062 41 1.24 0.191
0.111 9 1/09/90 5:30 0. 060 42 1.21 0.171
0.079 27 4/03/91 20:15 0.060 43 1.18 0.151
0.062 41 1/27/92 15:00 0.059 44 1. 15 0.131
0.075 31 6/09/93 12:15 0.058 45 1.12 0.111
0.074 34 11/17/93 16:45 0.057 46 1.10 0.091
0. 087 21 6/05/95 17:00 0. 057 47 1. 08 0.071
A-7
0 .092 16 7/19/96 19:30 0.053 48 1. 05 0.051
0.315 1 12/29/96 11:45 0.051 49 1. 03 0.031
0.157 4 10/04/97 14:15 0.047 50 1.01 0 .011
Com uted Peaks 0.274 100 .00 0.990
Computed Peaks 0.224 50. 00 0.980
Computed Peaks 0.183 25.00 0.960
Computed Peaks i 0.138 10.00 0. 900
Computed Peaks i 0.130 8. 00 0.875
Computed Peaks i 0.110 5. 00 0 .800
Computed Peaks j 0. 078 2. 00 0.500
Computed Peaks i 0.064 1.30 0.231
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P- 3
CB 2 JNCT#3
R'- `z
P- 05
B#3
P- 06
C #4
il
P- 07
C #5
Y
P 08
C t6
CB #7
9 EXISTING
10
Page 1 of 24
Existing 25-year Storm Event
History Cleared: 09:40:04 Wednesday,July 23, 2014
ROUTEHYD [] THRU [Untitled] USING KingCount Ir AND [25 yr] NOTZERO RELATIVE
RATIONAL
Reach Area TC Flow Full Q Full nDepth s e
nVel Nel CBasin /
ID ac) (min) (cfs) (cfs) ratio (ft) fds) (ft/s) Hyd
P-001 0.2300 6.37 0.2958 3.1992 0.09 O.1370 Dgam 5.7229 9.1650 BASIN 1
P-002 0.2300 6.43 0.2937 2.0190 0.15 0.1715 Dgam
4.1322 5.7839
P-003 0.2300 6.62 0.2920 2.7542 0.11 0.1468 D8am 5.1215 7.8901
P-004 0.9986 7.03 2.0096 4.3874 0.46 0.5939 pam 3.4969 3.5752 BASIN 2
P-005 0.9986 7.38 1.9335 5.3041 0.36 0.5222 pam 3.9816 4.3222
P-006 1.5314 8.11 2.8127 4.5801 0.61 0.7083 Diam 3.9205 3.7322 BASIN 3
P-007 2.0059 8.49 3.4055 6.4772 0.53 0.6436 am 5.3474 5.2781 BASIN 4
P-008 8.5854 3031 5.1283 7.9856 0.64 OJ285 p am 6.9085 6.5073 BASIN 5
P-009 14.5589 31.05 8.6565 9.2963 0.93 0.9549 Diam g•6056 7.5753 BASIN 6
P-010 23.6061 31.40 12.9579 16.9804 0.76 0.9811 p am
10.5811 9.6089 BASIN 7
From Rch Loss A Bend Junct Loss HW Loss Elev Max EI
Node To Node ft) t)ft) ft) ft)ft)
431.5800
CB #7 EXISTING 439.5105 0.7726 0.017 438.7554 443.3500
CB #6 CB #7 446.1251 0.2712 0.3440 446.1979 453.2100
CB #5 CB #6 448.2824 0.1196 0.0005 448.1633 457.9100
CB #4 CB #5 449.1584 0.2387 0.0029 448.9227 458.8100
CB #3 CB #4 449.8947 0.2462 0.0188 449.6673 458.8100
JNCT#3 CB #3 450.2498 0.1899 0.1851 450.2450 459.1100
No approach losses at node JNCT#2 because inverts and/or crowns are offset. I
CB #2 JNCT #3 450.6817 ------ 450.6817 459.0000
I,
JNCT#2 CB #2 453.9009 0.2651 0.1494 453.7851 458.5700
JNCT#1 JNCT #2 454.1437 0.5086 0.3312 453.9664 463.8000
CB #1 JNCT #1 455.1269 ------ 455.1269 457.6700
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L_
Page 2 of 24
Record Id: BASIN 1
Desi n Method Rational IDF Table: Kin CountyIr
Com osite C Calc
Description SubArea Sub c
Lawn (n=025) 0.15 ac 0.25
Pavement and roofs (n=0.90) 0.08 ac 0.90 i
Directh Connected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed 6.30 min
Directly Connected TC 6.30min
Record Id: BASIN 2
Design Method Rational IDF Table: KingCountylr
Composite C Calc
Descri tion SubArea Sub c
Lawn (n=0.25) 0.06 ac 0.25
Pavement and roofs (n=0.90) 0.71 ac 0.90
Directiv Connected TC Calc
Ty e Descri tion Len th Slo e Coeff Misc TT
Fixed 6.30 min
Directiv Connected TC 6.30min I
Record Id: BASIN 3
Desi n Method Rational IDF Table: Kin Count Ir
Com osite C Calc
Description SubArea Sub c
Lawn (n=0.25) 0.15 ac 0.25
Pavement and roofs (n=0.90) 0.38 ac 0.90
Directly Connected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed 6.30 min
Directly Connected TC 6.30min
Record Id: BASIN 4
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Page 3 of 24
I Design Method I Rational I IDF Table: I( KingCountyIr
Composite C Calc
Descri tion SubArea Sub c
Lawn (n=0.25) O.15 ac 0.25
Pavement and roofs (n=0.90) 0.32 ac 0.90
Directly Connected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed 6.30 min
Directly Connected TC 6.30min
Record Id: BASIN 5
Design Method Rational IDF Table: KingCountyIr
Composite C Calc
Description SubArea Sub c
Lawn (n=0.25) 3.44 ac 0.25
Pavement and roofs (n=0.90) 3.14 ac 0.90
Directly Connected TC Calc
Type Description Length Slo e Coeff Misc TT
Sheet Short rairie rass and lawns.: 0.15 393.00 ft 3.05% 0.1500 2.0 in 27.99 min
Channel (interm) Concrete pipe (n=0.012) 749.00 ft 2.56% 0.0120 1.84 min
Directly Connected TC 29.82min
Record Id: BASIN 6
Design Method Rational IDF Table: KingCountyIr
Composite C Calc
Description SubArea Sub c
Lawn (n=0.25) 2.68 ac 0.25
Pavement and roofs (n=0.90) 3.30 ac 0.90
Directly Connected TC Calc
Type Description Length Slope Coeff Misc TT
Sheet Short rairie rass and lawns.: 0.15 500.00 ft 3.20% 0.1500 2.50 in 33.29 min
Channel (interm) Concrete pi e (n=0.012) 756.00 ft 1.47% 0.0120 2.45 min
Directly Connected TC 35.74min
Record Id: BASIN 7
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Page 4 of 24
Design Method Rational I IDF Table: II KingCountylr I
Composite C Calc
Descri tion SubArea Sub c
Lawn (n=025) 5.49 ac 0.25
Pavement and roofs (n=0.90) 3.56 ac 0.90
Directly Connected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed 6.30 min
Directly Connected TC 6.30min
Record Id: CB #1
Descri :Prototy e Record Increment 0.10 ft
Start EL 454.7900 ft Max EL 457.6700 ft
Classification Catch Basin Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Existing OPQl
Sta e Storage Ratin Curve
454J900 ft 0.0000 cf 456.2900 ft 29.4525 c
454.8900 ft 1.9635 cf 456.3900 ft 31.4160 c
454.9900 ft 3.9270 cf 456.4900 ft 33.3795 c
455.0900 ft 5.8905 cf 456.5900 ft 35.3430 c
455.1900 ft 7.8540 cf 456.6900 ft 37.3065 c
455.2900 ft 9.8175 cf 456.7900 ft 39.2700 c
4553900 ft 11.7810 c 456.8900 ft 41.2335 c
455.4900 ft 13.7445 c 456.9900 ft 43.1970 c
455.5900 ft 15.7080 c 457.0900 ft 45.1605 c
455.6900 ft 17.671 c 457.1900 ft 47.1240 c
455.7900 ft 19.6350 c 457.2900 ft 49.0875 c
455.8900 ft 21.5985 c 457.3900 ft 51.0510 c
455.9900 ft 23.5620 c 457.4900 ft 53.0145 c
456.0900 ft 25.5255 c 457.5900 ft 54.9780 c
457.6700 ft 56.5489 c
Record Id: CB #2
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Page 5 of 24
Descrip: IPrototype Record I Increment I0.10 ft
Start EI.449.8600 ft Max El. 459.0000 ft
Classification Catch Basin Structure T e CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=020) Channelization Curved or Deflector
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Pro osed
Stage Storage Rating Curve
449.8600 ft 0.0001 cf 454.4600 ft 90.3211 cf
49.9600 ft 1.9636 cf 454.5600 ft 92.2846 cf
450.0600 ft 3.9271 cf 454.6600 ft 94.2481 cf
4 0.1600 ft 5.8906 cf 454.7600 ft 96.2116 cf
450.2600 ft 7.8541 cf 454.8600 ft 98.1751 cf
4 0.3600 ft 9.8176 cf 4 4.9600 ft 100.1386 c
4 0.4600 ft 11.7811 c 455.0600 ft 102.1021 c
4 0.5600 ft 13.7446 c 4 5.1600 ft 104.0656 c
450.6600 ft 15.7081 c 4».2600 ft 106.0291 c
450.7600 ft 17.6716 c 455.3600 ft 107.9926 c
4 0.8600 ft 19.6351 c 455.4600 ft 109.9561 c
4 0.9600 ft 21.5986 c 4 5.5600 ft 1 1 1.9196 c
4 1.0600 ft 23.5621 c 455.6600 ft 113.883 I c
451.1600 ft 25.5256 c 4 5.7600 ft 11.8466 c
451.2600 ft 27.4891 c 455.8600 ft 117.8101 c
451.3600 ft 29.4526 c 455.9600 ft 119.7736 c
451.4600 ft 31.4161 c 456.0600 ft 121.7371 c
451.5600 ft 33.3796 c 456.1600 ft 123.7006 c
451.6600 ft 35.3431 c 456.2600 ft 125.6641 c
451.7600 ft 37.3066 c 456.3600 ft 127.6276 c
451.8600 ft 39.2701 c 456.4600 ft 129.5911 c
451.9600 ft 41.2336 c 456.5600 ft 131.5546 c
452.0600 ft 43.1971 c 456.6600 ft 133.5181 c
452.1600 ft 45.1606 c 456.7600 ft 13.4816 c
452.2600 ft 47.1241 c 456.8600 ft 137.4451 c
452.3600 ft 49.0876 c 456.9600 ft 139.4086 c
452.4600 ft 51.0511 c 457.0600 ft 141.3721 c
452.5600 ft 53.0146 c 457.1600 ft 143.3356 c
452.6600 ft 54.9781 c 457.2600 ft 145.2991 c
452.7600 ft 56.9416 c 457.3600 ft 147.2626 c
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Page 6 of 24
I
452.8600 ft 58.90 1 c 457.4600 ft 149.2261 c
152.9600 ft 60.8686 c 457.5600 ft 151.1896 c
453.0600 ft 62.8321 c 457.6600 ft 153.1531 c
53.1600 ft 64.7956 c 457.7600 ft 155.1166 c
453.2600 ft 66.7591 c 457.8600 ft 157.0801 c
453.3600 ft 68.7226 c 457.9600 ft 159.0436 c
453.4600 ft 70.6861 c 458.0600 ft 161.0071 c
453.5600 ft 72.6496 c 458.1600 ft 162.9706 c
453.6600 ft 74.6131 c 458.2600 ft 164.9341 c
453.7600 ft 76.5766 c 458.3600 ft 166.8976 c
453.8600 ft 78.5401 c 458.4600 ft 168.8611 c
453.9600 ft 80.5036 c 458.5600 ft 170.8246 c
454.0600 ft 82.4671 c 458.6600 ft 172.7881 c
454.1600 ft 84.4306 c 4 8.7600 ft 174.7516 c
454.2600 ft 86.3941 c 458.8600 ft 176.7151 c
459.0000 ft 179.4642 c
Record Id: CB #3
Descrip:Prototv e Record Increment 0.10 ft
Start EL 448.9000 ft Max E1. 458.8100 ft
Classification Catch Basin Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Proposed
Sta e Stora e Ratin Curve
448.9000 ft 0.0000 cf 453.9000 ft 98.1749 cf
49.0000 ft 1.9634 cf 454.0000 ft 100.1384 c
49.1000 ft 3.9269 cf 454.1000 ft 102.1019 r!
449.2000 ft 5.8904 cf 454.2000 ft l 04.0654 c
449.3000 ft 7.8539 cf 454.3000 ft l 06.0289 c f'
449.4000 ft 9.8174 cf 454.4000 ft l 07.9924 c t1
449.5000 ft 11.7809 c 454.5000 ft 109.9559 ct
449.6000 ft 13.7444 c 454.6000 ft 1 119194 c t
449.7000 ft 1.7079 c 454.7000 ft 113.8829 ct
449.8000 ft 17.6714 c 454.8000 ft 1 15.8464 cf
I,
449.9000 ft 19.6349 c 454.9000 ft 1 17.8099 c
lf q_g
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Page 7 of 24
450.0000 ft 21.5984 c 455.0000 ft 1 19.7734 c
450.1000 ft 23.5619 c 455.1000 ft 121.7369 c
450.2000 ft 25.5254 c 455.2000 ft 123.7004 c
450.3000 ft 27.4889 c 455.3000 ft 12.6639 c
450.4000 ft 29.4524 c 455.4000 ft 127.6274 c
450.5000 ft 31.4159 c 455.5000 ft 129.5909 c
450.6000 ft 33.3794 c 455.6000 ft 131.5544 c
450.7000 ft 3.3429 c 455.7000 ft 133.5179 c
450.8000 ft 37.3064 c 455.8000 ft 135.4814 c
450.9000 ft 39.2699 c 455.9000 ft 137.4449 c
451.0000 ft 412334 c 456.0000 ft 139.4084 c
451.1000 ft 43.1969 c 4 6.1000 ft 141.3719 c
4 1.2000 ft 4.1604 c 4562000 ft 143.3354 c
451.3000 ft 47.1239 c 456.3000 ft 145.2989 c
451.4000 ft 49.0874 c 456.4000 ft 147.2624 c
451.5000 ft S 1.0509 c 456.5000 ft 149.2259 c
451.6000 ft 53.0144 c 4 6.6000 ft 151.1894 c
451.7000 ft 54.9779 c 456.7000 ft 153.1 29 c
451.8000 ft 56.9414 c 456.8000 ft I55.1164 c
451.9000 ft 58.9049 c 456.9000 ft 157.0799 c
452.0000 ft 60.8684 c 457.0000 ft 159.0434 c
452.1000 ft 62.8319 c 4 7.1000 ft 161.0069 c
452.2000 ft 64.7954 c 457.2000 ft 162.9704 c
452.3000 ft 66.7589 c 457.3000 ft 164.9339 c
452.4000 ft 68.7224 c 457.4000 ft 166.8974 c
452.5000 ft 70.6859 c 4 7.5000 ft 168.8609 c
452.6000 ft 72.6494 c 4 7.6000 ft 170.8244 c
452.7000 ft 74.6129 c 457.7000 ft 172.7879 c
452.8000 ft 76.5764 c 457.8000 ft 174.7514 c
452.9000 ft 78.5399 c 457.9000 ft 176.7149 c
453.0000 ft 80.5034 c 458.0000 ft 178.6784 c
453.1000 ft 82.4669 c 4 8.1000 ft 180.6419 c
453.2000 ft 84.4304 c 458.2000 ft 182.6054 c
453.3000 ft 86.3939 c 458.3000 ft 184.5689 c
453.4000 ft 88.3574 c 458.4000 ft 186.5324 c
453.5000 ft 90.3209 c 4 8.5000 ft 188.4959 c
453.6000 ft 92.2844 c 458.6000 ft 190.4594 c
453.7000 ft 94.2479 c 458.7000 ft 192.4229 c
A-$
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Page 8 of 24
II I 458.8100 ft 194.5829 c
Record Id: CB #4
Descrip:Prototvpe Record Increment 0.10 ft
Start EI.448.0500 ft Max El. 4 8.8100 ft
Classification Catch Basin Structure T e CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Pro osed
Stage Storage Rating Curve
448.0500 ft 0.0000 cf 4 3.4500 ft 106.0290 c
448.1500 ft 1.9635 cf 453.00 ft 107.9925 c
448.2500 ft 3.9270 cf 453.6500 ft 109.9560 c
448.3500 ft 5.8905 cf 453.7500 ft 111.9195 c
448.4500 ft 7.8540 cf 453.8500 ft 113.8830 c
448.5500 ft 9.8175 cf 453.9500 ft 115.8465 c
448.6500 ft 1 1.7810 cf 454.0500 ft 117.8100 c
448.7500 ft 13.7445 cf 454.1500 ft 119.7735 c
448.8500 ft 15.7080 cf 454.2500 ft 121.7370 c
448.9 00 ft 17.6715 cf 4 4.3500 ft 123.7005 c
449.0500 ft 19.6350 cf 454.4500 ft 125.6640 c
449.1500 ft 21.5985 cf 454.5500 ft 127.627 c
4492500 ft 23.5620 cf 454.6500 ft 129.5910 c
449.3500 ft 25.5255 cf 454.7500 ft 131.5545 c
449.4500 ft 27.4890 cf 454.8500 ft 133.5180 c
449.5500 ft 29.4525 cf 454.9500 ft 135.4815 c
449.6500 ft 31.4160 cf 4 5.0500 ft 137.44 0 c
449.7500 ft 33.3795 cf 455.1500 ft 139.408 c
449.8500 ft 35.3430 cf 455.2500 ft 141.3720 c
449.9500 ft 37.3065 cf 455.3500 ft 143.3355 c
450.0500 ft 39.2700 cf 455.4500 ft 145.2990 c
450.1500 ft 41.2335 cf 455.5500 ft 147.2625 c
450.2500 ft 43.1970 cf 455.6500 ft 149.2260 c
450.3500 ft 45.1605 cf 455.7500 ft 151.1895 c
450.4500 ft 47.1240 cf 455.8500 ft 153.1530 c
450.5500 ft 49.0875 cf 455.9500 ft 155.1165 c
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Page 9 of 24
450.6 00 ft 1.0 I O cf 456.0 00 ft 1 7.0800 ct
450.7500 ft 53.0145 cf 456.1500 ft 159.0435 c
450.8 00 ft 54.9780 cf 456.2500 ft 161.0070 c
450.9500 ft 56.9415 cf 456.3500 ft 162.9705 c
451 A 00 ft 58.9050 cf 456.4500 ft 164.9340 c
451.1500 ft 60.8685 cf 4 6.5500 ft 166.897 c
451.2500 ft 62.8320 cf 456.6500 ft 168.8610 c
451.3500 ft 64.7955 cf 456J500 ft 170.824 c
451.4500 ft 66.7590 cf 456.8500 ft 172.7880 c
4 I.5500 ft 68.7225 cf 4569 00 ft 174.7515 c
4 1.6500 ft 70.6860 cf 457A 00 ft 176.7150 c
4 1.7500 ft 72.649 cf 457.1 00 ft 178.6785 c
4 1.8500 ft 74.6130 cf 457.2500 ft 180.6420 c
1.9500 ft 76.5765 cf 457.3 00 ft 182.6055 c
2.0500 ft 78.5400 cf 457.4500 ft 184.690 c
452.1500 ft 80.5035 cf 457.5500 ft 186.5325 c
452.2500 ft 82.4670 cf 457.6500 ft 188.4960 c
452.3500 ft 84.4305 cf 457.7500 ft 190.4595 c
452.4500 ft 86.3940 cf 457.8500 ft 192.4230 c
452.5500 ft 88.3575 cf 457.9500 ft 194.3865 c
452.6500 ft 90.3210 cf 458.0500 ft 196.3500 c
452.7500 ft 92.2845 cf 4 8.1500 ft 198.3135 c
452.8500 ft 94.2480 cf 458.2500 ft 200.2770 ct
452.9500 ft 96.211 cf 4583500 ft 202.2405 ct
453.0500 ft 98.1750 cf 458.4500 ft 204.2040 ct
453.1500 ft 100.1385 c 458.5500 ft 206.1675 c
453.2500 ft 102.1020 c 458.6 00 ft 208.1310 c
458.8100 ft 211.2728 c
Record Id: CB #5
Descri :Prototy e Record Increment 0.10 ft
Start El.446.8000 ft Max E1. 457.9100 ft
Classification Manhole Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflector
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Pro osed
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Page 10 of 24
IStage Storage Rating Curve I
446.8000 ft 0.0000 cf 452.4000 ft 109.9560 c
446.9000 ft 1.9635 cf 452.5000 ft 111.9195 c
447.0000 ft 3.9270 cf 452.6000 ft 113.8830 c
447.1000 ft 5.8905 cf 452.7000 ft 115.8465 c
447.2000 ft 7.8540 cf 4 2.8000 ft 117.8100 c
447.3000 ft 9.8175 cf 452.9000 ft 119.7735 c
447.4000 ft 11 J810 cf 4 3.0000 ft 121.7370 c
447.5000 ft 13.7445 cf 4 3.1000 ft 123.7005 c
447.6000 ft 15.7080 cf 453.2000 ft 125.6640 c
447J000 ft 17.6715 cf 453.3000 ft 127.6275 c
447.8000 ft 19.6350 cf 453.4000 ft 129.5910 c
447.9000 ft 21.5985 cf 453.5000 ft 131.5545 c
448.0000 ft 23.5620 cf 453.6000 ft 133.5180 c
448.1000 ft 25.5255 cf 453.7000 ft 135.4815 c
448.2000 ft 27.4890 cf 453.8000 ft 137.4450 c
448.3000 ft 29.4525 cf 453.9000 ft 139.408 c
448.4000 ft 31.4160 cf 454.0000 ft 141.3720 c
448.5000 ft 33.3795 cf 454.1000 ft 143.3355 c
448.6000 ft 35.3430 cf 454.2000 ft 14.2990 c
448.7000 ft 37.3065 cf 454.3000 ft 147.2625 c
448.8000 ft 39.2700 cf 4 4.4000 ft 149.2260 c
448.9000 ft 41.2335 cf 4 4.000 ft 151.1895 c
449.0000 ft 43.1970 cf 454.6000 ft 153.1530 c
449.1000 ft 45.1605 cf 454.7000 ft 155.1165 c
449.2000 ft 47.1240 cf 454.8000 ft 157.0800 c
449.3000 ft 49.0875 cf 454.9000 ft 159.0435 c
449.4000 ft 51.0510 cf 455.0000 ft 161.0070 c
449.5000 ft 53.0145 cf 455.1000 ft 162.9705 c
449.6000 ft 54.9780 cf 455.2000 ft 164.9340 c
449.7000 ft 56.9415 cf 455.3000 ft 166.8975 c
449.8000 ft 58.9050 cf 455.4000 ft 168.8610 c
449.9000 ft 60.8685 cf 455.5000 ft 170.8245 c
450.0000 ft 62.8320 cf 455.6000 ft 172.7880 c
450.1000 ft 64.7955 cf 455.7000 ft 174.7515 c
450.2000 ft 66.7590 cf 455.8000 ft 176.7150 c
450.3000 ft 68.722 cf 4».9000 ft 178.6785 c
450.4000 fi 70.6860 cf 456.0000 ft 180.6420 c
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Page 1 1 of 24
u72.6495 cf 456.1000 ft 182.6055 c
450.6000 ft 74.6130 cf 456.2000 ft I 84.5690 c
450.7000 ft 76.5765 cf 456.3000 ft 186.5325 c
450.8000 ft 78.5400 cf 456.4000 ft 188.4960 c
450.9000 ft 80.5035 cf 456.5000 ft 190.459 c
451.0000 ft 82.4670 cf 456.6000 ft 192.4230 c
451.1000 ft 84.4305 cf 456.7000 ft 194.3865 c
451.2000 ft 863940 cf 456.8000 ft 196.3500 c
451.3000 ft 88.3575 cf 456.9000 ft 198.313 c
451.4000 ft 90.3210 cf 457.0000 ft 200.2770 c
451.5000 ft 92.2845 cf 457.1000 ft 202.240 c
451.6000 ft 94.2480 cf 457.2000 ft 204.2040 c
451.7000 ft 96.2115 cf 457.3000 ft 206.1675 c
451.8000 ft 98.1750 cf 457.4000 ft 208.1310 c
451.9000 ft 100.1385 c 457.5000 ft 210.0945 c
452.0000 ft 102.1020 c 457.6000 ft 212.0580 c
452.1000 ft 104.0655 c 457.7000 ft 214.0215 c
452.2000 ft 106.0290 c 457.8000 ft 215.9850 c
457.9100 ft 218.1452 c
Record Id: CB #6 I
Descri :Prototv e Record Increment 0.10 ft
Start EI.443.7600 ft Max E1. 453.2100 ft
Classification Manhole Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflector
Catch I.5000 ft Bottom Area 19.6350 sf
Condition Proposed
Stage Stora e Ratin Curve
443.7600 ft 0.0000 cf 448.5600 ft 94.2480 cf
443.8600 ft 1.9635 cf 448.6600 ft 96.2115 cf
443.9600 ft 3.9270 cf 448.7600 ft 98.1750 cf
444.0600 ft 5.8905 cf 448.8600 ft 100.1385 c
444.1600 ft 7.8540 cf 448.9600 ft 102.1020 c
444.2600 ft 9.8175 cf 449.0600 ft 104.0655 c
444.3600 ft 11.7810 c 449.1600 ft 106.0290 c
444.4600 ft 13.7445 c 449.2600 ft 107.9925 c
I- A_8
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Pa e 1? of 2=
444.5600 ft 15.7080 c 449.3600 ft 109.9560 c
444.6600 ft 17.6715 c 449.4600 ft 1 1 1.9195 c
444J600 ft 19.6350 c 449.5600 ft 113.8830 c
444.8600 ft 21.5985 c 449.6600 ft 115.8465 c
444.9600 ft 23.5620 c 449.7600 ft 1 17.8100 c
445.0600 ft 25.5255 c 449.8600 ft 1 19.7735 c
445.1600 ft 27.4890 c 449.9600 ft 121.7370 c
445.2600 ft 29.4525 c 450.0600 ft 123.7005 c
445.3600 ft 31.4160 c 450.1600 ft 125.6640 c
445.4600 ft 33.3795 c 450.2600 ft 127.6275 c
445.5600 ft 35.3430 c 450.3600 ft 129.5910 c
445.6600 ft 37.3065 c 450.4600 ft 131.5545 c
445.7600 ft 392700 c 450.5600 ft 133.5180 c
445.8600 ft 41.2335 c 450.6600 ft 135.4815 c
445.9600 ft 43.1970 c 450J600 ft 137.4450 c
446.0600 ft 45.1605 c 450.8600 ft 139.4085 c i
446.1600 ft 47.1240 c 450.9600 ft 141.3720 c
4462600 ft 49.0875 c 451.0600 ft 143.3355 c
446.3600 ft 51.0510 c 451.1600 ft 145.2990 c
446.4600 ft 53.0145 c 451.2600 ft 147.262 c
446.5600 ft 54.9780 c 4 13600 ft 149.2260 c
446.6600 ft 56.9415 c 4 1.4600 ft 151.189 c
446.7600 ft 58.9050 c 451.600 ft 153.1530 c
446.8600 ft 60.8685 c 451.6600 ft 155.116 c
446.9600 ft 62.8320 c 451.7600 ft 157.0800 c
447.0600 ft 64.7955 c 451.8600 ft 159.0435 c
447.1600 ft 66.7590 c 451.9600 ft 161.0070 c
447.2600 ft 68.7225 c 452.0600 ft 162.9705 c
447.3600 ft 70.6860 c 452.1600 ft 164.9340 c
447.4600 ft 72.649 c 4522600 ft 166.8975 c
447.5600 ft 74.6130 c 452.3600 ft 168.8610 c
447.6600 ft 76.5765 c 4 2.4600 ft 170.8245 c
447.7600 ft 78.5400 c 452.5600 ft 172.7880 c
447.8600 ft 80.5035 c 452.6600 ft 174.7515 c
447.9600 ft 82.4670 c 452.7600 ft 176.7150 c
448.0600 ft 84.4305 c 452.8600 ft 178.6785 c
448.1600 ft 86.3940 c 452.9600 ft 180.6420 c
448.2600 ft 88.3575 c 453.0600 ft 182.6055 c
r-t-
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Paee 13 of 2
90.3210 c 453.1600 ft I 84.5690 c
453.2100 ft 185.5504 c
Record Id: CB #7
Descri :Prototy e Record Increment 0.10 ft
Start El.435.8500 ft Max El. 443.3500 ft
Classification Manhole Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflector
Catch 1.5000 ft Bottom Area 19.63 0 sf
Condition Proposed
Sta e Stora e Rating Curve
435.8500 ft 0.0001 cf 439.6500 ft 74.6131 cf
35.9500 ft 1.9636 cf 439.7500 ft 76.5766 cf
436.0500 ft 3.9271 cf 439.8500 ft 78.5401 cf
436.1500 ft 5.8906 cf 439.9500 ft 80.5036 cf
36.2500 ft 7.8541 cf 440A 00 ft 82.4671 cf
436.3500 ft 9.8176 cf 440.1500 ft 84.4306 cf
436.4500 ft 11 J811 c 440.2500 ft 86.3941 cf
436.5500 ft 13.7446 c 440.3500 ft 88.3576 cf
436.6500 ft 15.7081 c 440.4 00 ft 90.3211 cf
36.7500 ft 17.6716 c 440.5 00 ft 922846 cf
436.8500 ft 19.63 1 c 440.6500 ft 94.2481 cf
436.9500 ft 21.5986 c 440.7500 ft 96.2116 cf
437.0500 ft 23.5621 c 440.8 00 ft 98.1751 cf
37.1500 ft 2.5256 c 4409 00 ft 100.1386 c
37.2500 ft 27.4891 c 441.0500 ft 102.1021 c
437.3500 ft 29.4526 c 441.1500 ft 104.0656 c
437.4500 ft 31.4161 c 441.2500 ft 106.0291 c
437.5500 ft 33.3796 c 441.3 00 ft 107.9926 c
437.6500 ft 35.3431 c 441.4 00 ft 109.9561 c
437.7500 ft 37.3066 c 441.5500 ft 1119196 c
437.8500 ft 39.2701 c 441.6500 ft 113.8831 c
437.9500 ft 41.2336 c 441.7 00 ft 115.8466 c
438.0500 ft 43.1971 c 441.8500 ft 117.8101 c
438.1500 ft 45.1606 c 441.9500 ft 119.7736 c
438.2500 ft 47.1241 c 442.0500 ft 121.7371 c
A-8
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Page 14 of 24
438.3500 ft 49.0876 c 442.1500 ft 123.7006 c
438.4500 ft 51.051 1 c 442.2500 ft 125.6641 c
438.5500 ft 53.0146 c 442.3500 ft 127.6276 c
438.6500 ft 54.9781 c 442.4500 ft 129.5911 c
438.7500 ft 56.9416 c 442.5500 ft 131.5546 c
438.8500 ft 58.9051 c 442.6500 ft 133.5181 c
438.9500 ft 60.8686 c 442.7500 ft 135.4816 c
439.0500 ft 62.8321 c 442.8500 ft 137.4451 c
439.1500 ft 64.7956 c 442.9500 ft 139.4086 c
439.2500 ft 66.7591 c 443.0500 ft 141.3721 c
439.3500 ft 68.7226 c 443.1500 ft 143.3356 c
439.4500 ft 70.6861 c 443.2500 ft 145.2991 c
443.3500 ft 147.2625 c
Record Id: EXISTING
Descri :Protot e Record Increment 0.10 ft
Start El.431.0800 ft Max E1. 438.0000 ft
Classification Manhole Structure T e CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Proposed
Stage Storage Rating Curve
431.0800 ft 0.0001 cf 434.5800 ft 68J226 cf
431.1800 ft 1.9636 cf 434.6800 ft 70.6861 cf
431.2800 ft 3.9271 cf 434.7800 ft 72.6496 cf
431.3800 ft 5.8906 cf 434.8800 ft 74.6131 cf
431.4800 ft 7.8541 cf 434.9800 ft 76.5766 cf
431.5800 ft 9.8176 cf 435.0800 ft 78.5401 cf
431.6800 ft 11.7811 c 435.1800 ft 80.5036 cf
431.7800 ft 13J446 c 435.2800 ft 82.4671 cf
431.8800 ft 15J081 c 435.3800 ft 84.4306 cf
431.9800 ft 17.6716 c 435.4800 ft 86.3941 cf
432.0800 ft 19.6351 c 435.5800 ft 88.3576 cf I
432.1800 ft 21.5986 c 435.6800 ft 90.3211 cf
432.2800 ft 23.5621 c 435.7800 ft 92.2846 cf I
432.3800 ft 25.5256 c 435.8800 ft 942481 cf
A_8
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Page 15 of 24
432.4800 ft 27.4891 c 435.9800 ft 96.2116 cf I
432.5800 ft 29.4526 c 436.0800 ft 98.1751 cf i
432.6800 ft 31.4161 c 436.1800 ft 100.1386 c
432.7800 ft 33.3796 c 436.2800 ft 102.1021 c
432.8800 ft 3.3431 ct 436.3800 ft 104.0656 c
432.9800 ft 37.3066 c 436.4800 ft 106.0291 c
433.0800 ft 39.2701 c 36.5800 ft 107.9926 c
433.1800 ft 41.2336 c 436.6800 ft 109.9561 c I
433.2800 ft 43.1971 c 436.7800 ft 1 l 1.9196 c
433.3800 ft 45.1606 c 436.8800 ft 113.8831 c
433.4800 ft 47.1241 c 436.9800 ft 1 15.8466 c
433.5800 ft 49.0876 c 437.0800 ft 117.8101 c
433.6800 ft 51.0511 c 437.1800 ft 119.7736 c
433.7800 ft 53.0146 c 437.2800 ft 121.7371 c
I
433.8800 ft 54.9781 c 437.3800 ft 123.7006 c
433.9800 ft 56.9416 c 437.4800 ft 125.6641 ct
434.0800 ft 58.9051 c 437.5800 ft 127.6276 c
434.1800 ft 60.8686 c 437.6800 ft 129.5911 c
434.2800 ft 62.8321 c 437J800 ft 131.5546 c
434.3800 ft 64.7956 c 437.8800 ft 133.5181 c
438.0000 ft 135.8745 c p
ys
Record Id: JNCT #1
Descrip:Prototype Record Increment 0.10 ft
Start El.453.8000 ft Max El. 463.8000 ft
Classification Catch Basin Structure Ty e CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20} Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Existin
Stage Stora e Ratin Cur e
453.8000 ft 0.0000 cf 458.8000 ft 98.1750 cf
4 3.9000 ft 1.9635 cf 458.9000 ft 100.1385 c
454.0000 ft 3.9270 cf 459.0000 ft 102.1020 c
454.1000 ft 5.8905 cf 459.1000 ft 104.0655 c
454.2000 ft 7.8540 cf 459.2000 ft 106.0290 c
I454.3000 ft 9.8175 cf 459.3000 ft 107.9925 c
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Page 16 of 24
454.4000 ft 11.7810 c 459.4000 ft 109.9560 c
454.5000 ft 13.7445 c 459.000 ft 1 1 19195 c
454.6000 ft 1.7080 c 459.6000 ft 1 13.8830 c
4 4.7000 ft 17.6715 c 459.7000 ft 115.8465 c
454.8000 ft 19.6350 c 459.8000 ft 1 17.8100 c
454.9000 ft 21.5985 c 459.9000 ft 119.7735 c
455.0000 ft 23.5620 c 460.0000 ft 121.7370 c
455.1000 ft 2.5255 c 460.1000 ft 123.7005 c
455.2000 ft 27.4890 c 460.2000 ft 125.6640 c
455.3000 ft 29.452 c 460.3000 ft 127.6275 c
455.4000 ft 31.4160 c 460.4000 ft 129.910 c
455.5000 ft 33.3795 c 460.5000 ft 131.5 45 c
455.6000 ft 35.3430 c 460.6000 ft 133.5180 c
455.7000 ft 37.3065 c 460.7000 ft 13.4815 c
455.8000 ft 39.2700 c 460.8000 ft 137.4450 c
455.9000 ft 41.2335 c 460.9000 ft 139.4085 c
456.0000 ft 43.1970 c 461.0000 ft 141.3720 c
456.1000 ft 45.1605 c 461.1000 ft 143.3355 c
456.2000 ft 47.1240 c 461.2000 ft 1452990 c
456.3000 ft 49.0875 c 461.3000 ft 147.2625 c
456.4000 ft 51.OS 10 c 461.4000 ft 149.2260 c
456.5000 ft 53.0145 c 461.5000 ft 1 1.1895 c
456.6000 ft 54.9780 c 461.6000 ft 153.1530 c
456J000 ft 56.9415 c 461.7000 ft 155.1165 c
456.8000 ft 58.9050 c 461.8000 ft 157.0800 c
456.9000 ft 60.8685 c 461.9000 ft 159.0435 c
457.0000 ft 62.8320 c 462.0000 ft 161.0070 ct
457.1000 ft 64.7955 c 462.1000 ft 162.9705 ct
457.2000 ft 66.7590 c 462.2000 ft 164.9340 c
4573000 ft 68.7225 c 462.3000 ft 166.8975 ct
457.4000 ft 70.6860 c 462.4000 ft 168.8610 c
457.5000 ft 72.6495 c 462.5000 ft 170.8245 c
457.6000 ft 74.6130 c 462.6000 ft 172.7880 c
457.7000 ft 76.5765 c 462.7000 ft 174.7515 c
457.8000 ft 78.5400 c 462.8000 ft 176.7150 c
457.9000 ft 80.5035 c 462.9000 ft 178.6785 c
458.0000 ft 82.4670 c 463.0000 ft 180.6420 c
458.1000 ft 84.430 c 463.1000 ft 182.6055 c
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Page 17 of 24
86.3940 c 463.2000 ft 184.690 c
4 8.3000 ft 88.3575 c 463.3000 ft 186.5325 c
458.4000 ft 90.3210 c 463.4000 ft 188.4960 c
458.5000 ft 92.2845 c 463.5000 ft 190.4595 c
458.6000 ft 94.2480 c 463.6000 ft 192.4230 c
463.8000 ft 196.3500 c
Record Id: JNCT #2
Descri :Prototy e Record Increment 0.10 ft
Start El.453.5700 ft Max EI. 4 8.5700 ft
Classification Catch Basin Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflector
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Existing
Stage Stora e Ratin Curve
453.5700 ft 0.0001 cf 456.0700 ft 49.0876 c
453.6700 ft 1.9636 cf 456.1700 ft 1.0511 c
453.7700 ft 3.9271 cf 456.2700 ft 53.0146 c
453.8700 ft 5.8906 cf 456.3700 ft 54.9781 c
453.9700 ft 7.8541 cf 456.4700 ft 56.9416 c
454.0700 ft 9.8176 cf 456.5700 ft 58.9051 c
454.1700 ft 11.7811 c 456.6700 ft 60.8686 c
454.2700 ft 13.7446 c 456.7700 ft 62.8321 c
454.3700 ft 15.7081 c 456.8700 ft 64.79 6 c
454.4700 ft 17.6716 c 456.9700 ft 66.7591 c
454.5700 ft 19.6351 c 457.0700 ft 68.7226 c
454.6700 ft 21.5986 c 457.1700 ft 70.6861 c
454.7700 ft 23.5621 c 457.2700 ft 72.6496 c
454.8700 ft 25.5256 c 457.3700 ft 74.6131 c
454.9700 ft 27.4891 c 457.4700 ft 76.5766 c
455.0700 ft 29.4526 c 457.5700 ft 78.5401 c
455.1700 ft 31.4161 c 457.6700 ft 80.5036 c
455.2700 ft 33.3796 c 457.7700 ft 82.4671 c
455.3700 ft 35.3431 c 457.8700 ft 84.4306 c
455.4700 ft 37.3066 c 457.9700 ft 86.3941 c
455.5700 ft 39.2701 c 458.0700 ft 88.3576 c I
I
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Page 18 of 24
455.6700 ft 41.2336 c 458.1700 ft 90.321 1 c
455.7700 ft 43.1971 c 458.2700 ft 92.2846 c
455.8700 ft 45.1606 c 458.3700 ft 94.2481 c
458.5700 ft 98.1750 c
Record Id: JNCT #3
Descrip:Prototype Record Increment 0.10 ft
Start EI.49.4700 ft Max EI. 459.1100 ft
Classification Catch Basin Structure Tv e CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Pro osed
Stage Storage Rating Curve
449.4700 ft 0.0000 cf 454.3700 ft 96.2115 cf
449.5700 ft 1.9635 cf 454.4700 ft 98.1750 cf
449.6700 ft 3.9270 cf 454.5700 ft 100.1385 c
449.7700 ft 5.8905 cf 454.6700 ft 102.1020 c
449.8700 ft 7.8540 cf 454.7700 ft ]04.0655 c
449.9700 ft 9.817 cf 454.8700 ft 106.0290 c
450.0700 ft 1 1 J810 c 454.9700 ft 107.9925 c
450.1700 ft 13.7445 c 455.0700 ft 109.9560 c
450.2700 ft 15.7080 c 455.1700 ft 1 1 1.9195 c
450.3700 ft 17.6715 c 455.2700 ft 1 13.8830 c
450.4700 ft 19.6350 c 455.3700 ft 1 15.8465 c
450.5700 ft 21.5985 c 455.4700 ft 1 17.8100 c
I'
450.6700 ft 23.5620 c 455.5700 ft 1 19.7735 c
450.7700 ft 25.52 5 c 455.6700 ft 121 J370 c
450.8700 ft 27.4890 c 455.7700 ft 123.7005 c
450.9700 ft 29.4525 c 455.8700 ft 125.6640 c
451.0700 ft 31.4160 c 455.9700 ft 127.6275 c
451.1700 ft 33.379 c 456.0700 ft 129.5910 c
451.2700 ft 35.3430 c 456.1700 ft 131.5545 c
451.3700 ft 37.3065 c 456.2700 ft 133.5180 c
451.4700 ft 39.2700 c 456.3700 ft 135.4815 c
451.5700 ft 41.2335 c 456.4700 ft 137.4450 c
451.6700 ft 43.1970 c 456.5700 ft 139.4085 c
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Page 19 of 24
451.7700 ft 45.1605 c 456.6700 ft 141.3720 c
451.8700 ft 47.1240 c 456.7700 ft 143.3355 c
451.9700 ft 49.0875 c 456.8700 ft 145.2990 c
452.0700 ft 51.0510 c 456.9700 ft 147.2625 c
452.1700 ft 53.0145 c 457.0700 ft 149.2260 c
452.2700 ft 54.9780 c 457.1700 ft 151.1895 c
452.3700 ft 56.9415 c 457.2700 ft 153.1530 c
452.4700 ft 58.9050 c 457.3700 ft 155.1165 c
452.5700 ft 60.8685 c 457.4700 ft 157.0800 c
452.6700 ft 62.8320 c 457.5700 ft 159.0435 c
452.7700 ft 64.795 c 457.6700 ft 161.0070 c
452.8700 ft 66.7590 c 457.7700 ft 162.9705 c
452.9700 ft 68.7225 c 457.8700 ft 164.9340 c
453.0700 ft 70.6860 c 457.9700 ft 166.8975 c
453.1700 ft 72.6495 c 458.0700 ft 168.8610 c
453.2700 ft 74.6130 c 4 8.1700 ft 170.8245 c
453.3700 ft 76.5765 c 458.2700 ft 172.7880 c
453.4700 ft 78.5400 c 458.3700 ft 174.7515 c
453.5700 ft 80.5035 c 458.4700 ft 176.7150 c
453.6700 ft 82.4670 c 458.5700 ft 178.6785 c
453.7700 ft 84.4305 c 458.6700 ft 180.6420 c
453.8700 ft 86.3940 c 458.7700 ft 182.6055 c
453.9700 ft 88.3575 c 458.8700 ft 184.5690 c
454.0700 ft 90.3210 c 458.9700 ft 186.5325 c
454.1700 ft 92.2845 c 459.0700 ft 188.4960 c
459.1100 ft 189.2811 c
Record Id: P-001
Section Sha e: Circular
Uniform Flow Method: Manning's Coefficient: 0.0100
Routing Method: Travel Time Translation
DnNode JNCT#1 U Node CB #1
Material Plastic Size 8" Diam
Ent Losses Groove End w/Headwall
Len th 24.0000 ft Slo e 4.13%
U [nvert 454.7900 ft Dn Invert 453.8000 ft
Conduit Constraints
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Page ?0 of 24
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft
Dro across MH 0.0000 ft E Infil Rate 0.0000 in/hr
Up [nvert 453.8000 ft Dn Invert 4 4.7900 ft
Match inverts.
DnNode JNCT#1 U Node CB #1
Record Id: P-002
Section Sha e: Circular
Uniform Flow Method: Manning's Coefficient: 0.0100
Routing Method: Travel Time Translation
DnNode JNCT #2 U Node JNCT#1
Material Plastic Size 8" Diam
Ent Losses Groove End w/Headwall
Length 14.0000 ft Slo e 1.64%
U Invert 453.8000 ft Dn Invert 453.5700 ft
Conduit Constraints
Min Vel Max Vel Min Slo e Max Slo e Min Cover
2.00 ftls 15.00 fUs 0.50% 2.00°/a 3.00 ft
Drop across MH 0.0000 ft Ex Infil Rate 0.0000 in,'hr
U [nvert 453.5700 ft Dn Invert 453.8000 ft
Match inverts.
DnNode JNCT #2 UpNode JNC"I #1
Record Id: P-003
Section Shape: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routin Method: Travel Time Translation
DnNode CB #2 U Node JNC"I'#2
Material Conc-Spun Size 8" Diam
Ent Losses Groove End w/Headwall
Length 60.0000 ft Slo e 5.17%
Up Im ert 4 3.5700 ft Dn Invert 450.4700 ft
Conduit Constraints
Min Vel Max Vel Min Slo e Max Slo e Min Cover
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Page 2l of 24
I2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft I I
Dro across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr
U Invert 450.4700 ft Dn [nvert 453.5700 ft
Match inverts.
DnNode CB #2 UpNode JNCT #2
Record Id: P-004
Section Sha e: Circular
Uniform Flow Method: Mannin 's Coefficient: 0.0130
Routing Method: T'ravel Time Translation
DnNode JNCT#3 UpNode CB #2
Material Conc-S un Size 15" Diam
Ent Losses Groove End w/Headwall
Length 85.0000 ft Slope 0.46% I
U Invert 449.8600 ft Dn Invert 449.4700 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ftls 0.50% 2.00% 3.00 ft
Dro across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr li
Up Invert 449.4700 ft Dn Invert 449.8600 ft I
Match inverts.
DnNode JNCT#3 U Node CB #2
Record Id: P-005
Section Shape: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routing Method: Travel Time Translation
DnNode CB #3 U Node JNCT#3
Material Conc-S un Size 15" Diam
Ent Losses Groove End w/Headwall
Len th 85.0000 ft Slo e 0.67%
I'
U Invert 449.4700 ft Dn Invert 448.9000 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slo e Min Cover
2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft
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Page 22 of 24
IDrop across MH I0.0000 ft I E Infil Rate 0.0000 in,hr
U Invert 448.9000 ft Dn Invert 449.4700 ft
Match inverts.
DnNode CB #3 UpNode JNCT #3
Record Id: P-006
Section Shape: Circular
Uniform Flow Method: Mannin 's Coefficient: 0.0130
Routin Method: Travel Time Translation
DnNode CB #4 UpNode CB #3
Material Conc-Spun Size 15" Diam
Ent Losses Groove End w/Headwall
Len th 170.0000 ft Slo e 0.50°/a
Up Im ert 448.9000 ft Dn Invert 448.0500 ft
Conduit Constraints
Min Vel Max Vel Min Slo e Max Slo e Min Cover
2.00 ft/s 1.00 ft/s 0.50% 2.00% 3.00 ft
Dro across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr
U Im-ert 448.0500 ft Dn Im-ert 448.9000 ft
Match inverts.
DnNode CB #4 U Node CB#3 i
Record Id: P-007
Section Shape: Circular
Uniform Flow Method: Mannin 's Coefficient: 0.0130
Routing Method: Travel Time Translation
DnNode CB #5 UpNode CB #4
Material Conc-S un Size 15" Diam
Ent Losses Groove End w/Headwall
Length 125.0000 ft Slope 1.00%
U Invert 448.0500 ft Dn Invert 446.8000 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 fUs 0.50% 2.00% 3.00 ft
Dro across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr
Up Invert 446.8000 ft Dn Invert 448.0500 ft
A-8
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Page 23 of 24
IMatch inverts. I
DnNode CB #5 U Node CB #4
Record Id: P-008
Section Sha e: Circular
CJniform Flow Method: Mannin 's Coefficient: 0.0130
Routing Method: Travel Time Translation
DnNode CB #6 U Node CB #5
Material Conc-S un Size 15" Diam
Ent Losses Groove End w/Headwall
Length 200.0000 ft Slope 1.52%
U Invert 446.8000 ft Dn Invert 443.7600 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft
Dro across MH 0.0000 ft E Infil Rate 0.0000 in/hr II
Up Invert 443.7600 ft Dn Invert 446.8000 ft
Match inverts.
DnNode CB #6 U Node CB #5
Record Id: P-009
Section Shape: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routing Method: Travel Time Translation
DnNode CB #7 U Node CB #6
Material Conc-Spun Size 15" Diam
Ent Losses Groove End w/Headwall
Len th 384.0000 ft Slo e 2.06°/a
U Invert 443.7600 ft Dn Invert 435.8500 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slo e Min Cover
2.00 ft/s 15.00 fUs 0.50% 2.00% 3.00 ft
Drop across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr
U Invert 435.8500 ft Dn Invert 443.7600 ft
Match inverts.
DnNode CB #7 UpNode CB #6
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Page 24 of 24
Record Id: P-010
Section Shape: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routin Method: Travel Time T'ranslation
DnNode EXISTING U Node CB #7
Material Conc-Spun Size 18" Diam
Ent Losses Groove End w/Headwall
Len th 222.0000 ft Slo e 2.60%
Up Invert 436.8500 ft Dn Invert 431.0800 ft
Conduit Constraints
iVlin Vel Max Vel Min Slo e Max Slo e Min Cover
2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft
Drop across MH 0.0000 ft E c/Infil Rate 0.0000 in/hr
U Invert 431.0800 ft Dn Invert 436.8500 ft
Match inverts.
DnNode EXISTING UpNode CB #7
Licensed to: AHBL
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Page 1 of 24
Proposed 25-year Storm Event
History Cleared: 09:34:22 Wednesday,July 23, 2014
ROUTEHYD [] THRU [Untitled] USING KingCountyIr AND [25 yr] NOTZERO RELATIVE
RATIONAL
Reach Area TC Flow Full Q Full nDepth Size nVel fVel CBasin /
ID ac) (m n) (cfs) (cfs) ratio (ft) ft/s) (ft/s) Hyd
P-001 0.2336 6.36 0.4298 3.1992 0.13 0.1650 Dgam 6.3855 9.1650 BASIN 1
P-002 0.2336 6.41 0.4270 2.0190 0.21 0.2080 Dgam
4.5919 5.7839
P-003 0.2336 6.9 0.4248 2.7542 0.15 0.1768 g SJ310 7.8901Diam
P-004 1.0022 6.99 2.1464 4.3874 0.49 0.6171 p,am 3.5556 3.5752 BASIN 2
P-005 1.0022 7.34 2.0661 5.3041 0.39 0.5417 p am 4.0530 4.3222
P-006 1.5350 8.05 2.9456 4.5801 0.64 0.7291 piam 3.9641 3.7322 BASIN 3
15"I P-007 2.0095 8.44 3.5347 6.4772 0.55 0.6583 Diam 5.3953 5.2781 BASIN 4
P-008 8.5890 30.31 5.1770 7.9856 0.65 •732 Diam 6.9250 6.5073 BASIN
P-009 14.5625 31.05 8.70 0 9.2963 0.94 0.9598 piam
8.6095 7.5753 BASIN 6
P-010 23.6097 31.40 13.0058 16.9804 OJ7 0.9833 p,am
10.5931 9.6089 BASIN 7
From Rch Loss A Bend Junct Loss HW Loss Elev Max E1
Node To Node ft) ft)ft) ft) ft)ft)
431.5800
CB #7 EXISTING 439.5222 0.7813 0.0067 438.7475 443.3500
CB #6 CB #7 446.1414 0.2763 0.2771 446.1422 453.2100
CB #5 CB #6 448.2933 0.1288 0.0010 448.1655 457.9100
CB #4 CB #5 449.1865 0.2440 0.0018 448.9443 458.8100
CB #3 CB #4 449.9219 02551 0.0390 449.7058 458.8100
JNCT #3 CB #3 450.2811 0.1963 0.1340 450.2188 459.1 100
No approach losses at node JNCT#2 because inverts and/or crowns are offset.
CB #2 JNCT#3 450.7126 ------ 450.7126 459.0000
JNCT #2 CB #2 453.9850 03274 0.0348 453.6924 458.5700
JNCT #1 JNCT #2 454.2280 0.6332 0.2470 453.8419 463.8000
CB #1 JNCT #1 455.21 l4 ------ 455.2114 457.6700
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Page 2 of 24
Record Id: BASIN 1
Desi n Method Rational IDF Table: KingCount Ir
Com osite C Calc
Description SubArea Sub c
Lawn (n=0.25) 0.08 ac 0.25
Pavement and roofs (n=0.90) 0.15 ac 0.90
Directly Connected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed 6.30 min
Directly Connected TC 6.30min
Record Id: BASIN 2
Design Method Rational IDF Table: KingCountylr
Composite C Calc
Descri tion SubArea Sub c
Lawn (n=0.25) 0.06 ac 0.25
Pavement and roofs (n=0.90) 0.71 ac 0.90
Directly Connected TC Calc
Tv e Descri tion Len th Slo e Coeff Misc TT
Fixed 6.30 min
Directly Connected TC 6.30min
Record Id: BASIN 3
Desi n Method Rational IDF Table: KingCountylr
Com osite C Calc
Description SubArea Sub c
Lawn (n=0.25) 0.15 ac 0.25
Pavement and roofs (n=0.90) 0.38 ac 0.90
Directly Con ected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed 6.30 min
Directly Connected TC 6.30min
Record Id: BASIN 4
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Page 3 of 24
I Design Method I Rational I IDF Table: II KingCountylr I
Com osite C Calc
Descri tion SubArea Sub c
Lawn (n=0.25) O.15 ac 0.25 i
Pavement and roofs (n=0.90) 0.32 ac 0.90
I
Directly Connected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed 6.30 min
Directly Connected TC 6.30min
Record Id: BASIN 5
Desi n Method Rational IDF Table: Kin CountyIr
Composite C Calc
Description SubArea Sub c
Lawn (n=0.25) 3.44 ac 0.25
Pavement and roofs (n=0.90) 3.14 ac 0.90
Directly Connected TC Calc
Ty e Descri tion Len th Slope Coeff Misc TT
Sheet Short rairie rass and lawns.: 0.15 393.00 ft 3.05% 0.1500 2.50 in 27.99 min
Channel (interm) Concrete pipe (n=0Al2) 749.00 ft 2.56% 0.0120 1.84 min
Directiv Connected TC 29.82min
Record Id: BASIN 6
Desi n Method Rational IDF Table: KingCountyIr
Com osite C Calc
Description SubArea Sub c
Lawn (n=0.25) 2.68 ac 0.25
Pavement and roofs (n=0.90) 3.30 ac 0.90
Directly Connected TC Calc
Type Description Length Slope Coeff' Misc TT
Sheet Short rairie rass and lawns.: 0.15 500.00 ft 3.20% 0.1500 2.50 in 3329 min
Channel (interm) Concrete i e (n=0.012) 756.00 ft 1.47% 0.0120 2.45 min
Directly Connected TC 35.74min
Record Id: BASIN 7
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Page 4 of 24
Design Method I Rational IDF Table: II KingCountylr I
Com osite C Calc
Descri tion SubArea Sub c
Lawn (n=0.25) 5.49 ac 0.25
Pavement and roofs (n=0.90) 3.56 ac 0.90
Directiv Connected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed 6.30 min
Directiv Connected TC 6.30min
Record Id: CB #1
Descri :Prototy e Record Increment 0.10 ft
Start EI.4 4.7900 ft Max EL 457.6700 ft
Classification Catch Basin Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Existing
Stage Storage Ratin Curve
454.7900 ft 0.0000 cf 4 6.2900 ft 29.4525 c
454.8900 ft 1.9635 cf 4 6.3900 ft 31.4160 c
454.9900 ft 3.9270 cf 456.4900 ft 33.3795 c
455.0900 ft .8905 cf 4 6.5900 ft 3.3430 c
455.1900 ft 7.8540 cf 456.6900 ft 37.3065 c
455.2900 ft 9.8175 cf 4 6.7900 ft 39.2700 c
455.3900 ft 11.7810 c 456.8900 ft 41.2335 c
455.4900 ft 13.7445 c 456.9900 ft 43.1970 c
455.5900 ft 15.7080 c 457.0900 ft 45.1605 c
455.6900 ft 17.6715 c 457.1900 ft 47.1240 c
455.7900 ft 19.6350 c 457.2900 ft 49.0875 c
455.8900 ft 21.5985 c 457.3900 ft 51.0 10 c
455.9900 ft 23.5620 c 457.4900 ft 53.0145 c
456.0900 ft 25.5255 c 457.5900 ft 4.9780 c
457.6700 ft 56.5489 c
Record Id: CB #2
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Page 5 of 24
Descrip:IPrototype Record I[ncrement I0.10 ft I
Start EI.449.8600 ft Max EI. 459.0000 ft
Classification Catch Basin Structure T e CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Pro osed
Stage Storage Rating Curve
449.8600 ft 0.0001 cf 454.4600 ft 90.321 1 cf
449.9600 ft 1.9636 cf 454.5600 ft 92.2846 cf
450.0600 ft 3.9271 cf 454.6600 ft 94.2481 cf
450.1600 ft 5.8906 cf 454.7600 fr 96.2116 cf
450.2600 ft 7.8541 cf 454.8600 ft 98.1751 cf
450.3600 ft 9.8176 cf 454.9600 ft 100.1386 c
450.4600 ft 11.781 1 c 455.0600 ft 102.1021 c
450.5600 ft 13.7446 c 4 5.1600 ft 104.0656 c
450.6600 ft 15.7081 c 45.2600 ft 106.0291 c
450.7600 ft 17.6716 c 455.3600 ft 107.9926 c
450.8600 ft 19.6351 c 455.4600 ft 109.9561 c
450.9600 ft 21.5986 c 455.5600 ft 1 11.9196 c
451.0600 ft 23.5621 c 455.6600 ft 113.8831 c
451.1600 ft 25.5256 c 455.7600 ft 115.8466 c
4 1.2600 ft 27.4891 c 455.8600 ft 117.8101 c
451.3600 ft 29.4526 c 455.9600 ft 119J736 c
451.4600 ft 31.4161 c 456.0600 ft 121.7371 c
451.5600 ft 33.3796 c 456.1600 ft 123.7006 c
451.6600 ft 35.3431 c 456.2600 ft 125.6641 c
451.7600 ft 37.3066 c 456.3600 ft 127.6276 c
451.8600 fi 39.2701 c 456.4600 ft 129.5911 c
451.9600 ft 41.2336 c 456.5600 ft 131.5546 c
452.0600 ft 43.1971 c 456.6600 ft 133.5181 c
452.1600 ft 45.1606 c }6.7600 ft 135.4816 c
452.2600 ft 47.1241 c 4 6.8600 ft 137.4451 c
452.3600 ft 49.0876 c 456.9600 ft 139.4086 c
452.4600 ft 51.0511 c 457.0600 ft 141.3721 c
452.5600 ft 53.0146 c 457.1600 ft 143.3356 c
452.6600 ft 54.9781 c 457.2600 ft 145.2991 c
452.7600 ft 56.9416 c 457.3600 ft 147.2626 c
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Page 6 of 24
452.8600 ft 58.9051 c 457.4600 ft 149.2261 c
452.9600 ft 60.8686 c 457.5600 ft 1 I.1896 c
453.0600 ft 62.8321 c 457.6600 ft 153.1531 c
453.1600 ft 64.7956 c 457.7600 fr 155.1166 c I
4 3.2600 ft 66.7591 c 457.8600 ft 157.0801 c
453.3600 ft 68.7??6 c 4 7.9600 ft 159.0436 c
4 3.4600 ft 70.6861 c 458.0600 ft 161.0071 c
453.5600 ft 72.6496 c 458.1600 ft 162.9706 c
453.6600 ft 74.6131 c 458.2600 ft 164.9341 c
453.7600 ft 76.5766 c 4 8.3600 ft 166.8976 c
453.8600 ft 78.5401 c 458.4600 ft 168.861 1 c
453.9600 ft 80.5036 c 4 8.5600 ft 170.8246 c
454.0600 ft 82.4671 c 458.6600 ft 172.7881 c
454.1600 ft 84.4306 c 458J600 ft 174J516 c
454.2600 ft 86.3941 c 458.8600 ft 176J151 c
459.0000 ft 179.4642 ct
Record Id: CB #3
Descri :Protot e Record Increment 0.10 ft
Start EI.448.9000 ft Max E1. 4 8.8100 ft
Classification Catch Basin Structure Tvpe CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch I.5000 ft Bottom Area 19.6350 sf
Condition Proposed
Sta e Stora e Ratin Curve
448.9000 ft 0.0000 cf 4 3.9000 ft 98.1749 cf
449.0000 ft 1.9634 cf 454.0000 ft 100.1384 c
449.1000 ft 3.9269 cf 454.1000 ft 102.1019 c
449.2000 ft 5.8904 cf 454.2000 ft 104.0654 c
449.3000 ft 7.8539 cf 454.3000 ft 106.0289 c
449.4000 ft 9.8174 cf 454.4000 ft 107.9924 c
449.5000 ft 11.7809 c 454.5000 ft 109.9559 c
449.6000 ft 13.7444 c 454.6000 ft 111.9194 c
449.7000 ft 15.7079 c 454.7000 ft 113.8829 c
449.8000 ft 17.6714 c 454.8000 ft 115.8464 c
449.9000 ft 19.6349 c 454.9000 ft 117.8099 c
A-8
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i Page 7 of 24
Ui ;_450.0000 ft 21.5984 c 455.0000 ft 119.7734 c
4 0.1000 ft 23.5619 c 45.1000 ft 121.7369 c
I ,-
00450.2000 ft 25.5254 c 455.2000 ft 123.7004 c
450.3000 ft 27.4889 c 455.3000 ft 125.6639 c
450.4000 ft 29.4524 c 455.4000 ft 127.6274 c
I - ' 450.5000 ft 31.4159 c 455.5000 ft 129.5909 c
I -- 450.6000 ft 33.3794 c 455.6000 ft 131.5544 c
0000i j 450.7000 ft 35.3429 c 455.7000 ft 133.5179 c
450.8000 ft 37.3064 c 4 5.8000 ft 135.4814 c
j 450.9000 ft 39.2699 c 455.9000 ft 137.4449 c
451.0000 ft 41.2334 c 456.0000 ft 139.4084 c
451.1000 ft 43.1969 c 456.1000 ft 141.3719 c
451.2000 ft 45.1604 c 4 6.2000 ft 143.3354 c
451.3000 ft 47.1239 c 4563000 ft 145.2989 c
i 451.4000 ft 49.0874 c 456.4000 ft 147.2624 c
451.5000 ft 51.0509 c 456.5000 ft 149.2259 c
451.6000 ft 53.0144 c 456.6000 ft 151.1894 c
451.7000 ft 54.9779 c 456.7000 ft 153.1529 c
451.8000 ft 56.9414 c 456.8000 ft 155.1164 c
451.9000 ft 58.9049 c 456.9000 ft 157.0799 c
452.0000 ft 60.8684 c 457.0000 ft 159.0434 c
0000452.1000 ft 62.8319 c 457.1000 ft 161.0069 c
i 452.2000 ft 64.7954 c 457.2000 ft 162.9704 c
452.3000 ft 66.7589 c 457.3000 ft 164.9339 ck
452.4000 ft 68J224 c 457.4000 ft 166.8974 c
452.5000 ft 70.6859 c 457.5000 ft 168.8609 c
II l_452.6000 ft 72.6494 c 457.6000 ft 170.8244 c I
I _4 2.7000 ft 74.6129 c 457.7000 ft 172.7879 c
452.8000 ft 76.5764 c 457.8000 ft 174.7514 c I
452.9000 ft 78.5399 c 457.9000 ft 176.7149 c I
453.0000 ft 80.5034 c 458.0000 ft 178.6784 c
I453.1000 ft 82.4669 c 458.1000 ft 180.6419 c
453.2000 ft 84.4304 c 458.2000 ft 182.6054 c
453.3000 ft 86.3939 c 458.3000 ft 184.5689 c
453.4000 ft 88.3574 c 458.4000 ft 186.5324 c
453.5000 ft 90.3209 c 458.5000 ft 188.4959 c
453.6000 ft 92.2844 c 458.6000 ft 190.4594 c
453.7000 ft 94.2479 c 458.7000 ft 192.4229 c
A-8
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Page S of 24
II I 458.8100 ft 194.5829 c I
Record Id: CB #4
Descrip:Prototype Record Increment 0.10 ft
Start EI.448.0500 ft Max El. 4 8.8100 ft
Classification Catch Basin Structure T e CB-"TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflector
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Pro osed
Stage Storage Rating Curve
448.0500 ft 0.0000 cf 4 3.4 00 ft 106.0290 c
448.1500 ft 1.9635 cf 453.5 00 ft 107.992 c
448.2500 ft 3.9270 cf 453.6500 ft 109.9560 c
448.3500 ft 5.8905 cf 453.7500 ft 1 1 1.9195 c
448.4500 ft 7.8540 cf 453.8500 ft 113.8830 c
448.5500 ft 9.8175 cf 453.9500 ft 115.8465 c
448.6500 ft 11.7810 cf 454.0500 ft 117.8100 c
448.7500 ft 13.7445 cf 454.1500 ft 119.7735 c I
448.8500 ft 15.7080 cf 454.2500 ft 121.7370 c
448.9500 ft 17.6715 cf 454.3500 ft 123.7005 c
449.0500 ft 19.6350 cf 454.4500 ft 125.6640 c I,
449.1500 ft 21.598 cf 454.5500 ft 127.6275 c I
449.2500 ft 23.5620 cf 454.6500 ft 129.5910 c i
449.3500 ft 25.5255 cf 454J500 ft 131.5545 c
449.4500 ft 27.4890 cf 454.8500 ft 133.5180 c
449.5500 ft 29.4525 cf 454.9500 ft 135.4815 c
449.6500 ft 31.4160 cf 455.0500 ft 137.4450 c
449.7500 ft 33.3795 cf 455.1500 ft 139.4085 c
449.8500 ft 35.3430 cf 455.2500 ft 141.3720 c0000
449.9500 ft 37.3065 cf 455.3500 ft 143.3355 c
450.0500 ft 39.2700 cf 455.4500 ft 145.2990 c
450.1500 ft 41.2335 cf 455.5500 ft 147.2625 c
450.2500 ft 43.1970 cf 455.6500 ft 149.2260 c
450.3500 ft 45.1605 cf 455.7500 ft 1 S l.l 895 c
450.4500 ft 47.1240 cf 455.8500 ft 153.1530 c
450.5500 ft 49.0875 cf 455.9500 ft 155.1165 c
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Page 9 of 24
450.6 00 ft 51.0 10 cf 456.0 00 ft 1 7.0800 c
450.7500 ft 53.0145 cf 456.1500 ft 1 9.0435 c
450.8500 ft 54.9780 cf 456.2500 ft 161.0070 c
4 09 00 ft 56.9415 cf 456.3500 ft 162.9705 c
4 1.0500 ft 58.9050 cf 456.4500 ft 164.9340 c
451.1500 ft 60.868 cf 456.5500 ft 166.8975 c
451.2500 ft 62.8320 cf 4 6.6500 ft 168.8610 c
451.3500 ft 64J955 cf 456.7500 ft 170.8245 c
451.4500 ft 66.7590 cf 4 6.8500 ft 172.7880 c
4 1.5500 ft 68.7225 cf 456.9500 ft 174.7515 c
451.6500 ft 70.6860 cf 457.0500 ft 176.7150 c
451.7500 ft 72.6495 cf 457.1500 ft 178.6785 c
451.8500 ft 74.6130 cf 457.2500 ft 180.6420 c
451.9500 ft 76.5765 cf 457.3500 ft 182.6055 c
452.0500 ft 78.5400 cf 457.4 00 ft 184.5690 c
452.1500 ft 80.5035 cf 457.5500 ft 186.5325 c
452.2500 ft 82.4670 cf 457.6500 ft 188.4960 c
452.3500 ft 84.4305 cf 457.7500 ft 190.4595 c
452.4500 ft 86.3940 cf 457.8500 ft 192.4230 c
452.5500 ft 88.3575 cf 4 7.9500 ft 194.3865 c
452.6500 ft 90.3210 cf 458.0500 ft 196.3500 c
452.7500 ft 92.2845 cf 458.1500 ft 1983135 c
452.8500 ft 94.2480 cf 458.2500 ft 200.2770 c
452.9500 ft 96.2115 cf 4 8.3500 ft 202,2405 c
453.0500 ft 98.1750 cf 458.4500 ft 204.2040 c
453.1500 ft 100.1385 c 458.5500 ft 206.1675 c
453.2500 ft 102.1020 c 458.6500 ft 208.1310 c
458.8100 ft 211.2728 c
Record Id: CB #5
Descrip:Prototy e Record Increment 0.10 ft
Start EI.446.8000 ft Max EL 457.9100 ft
Classification Manhole Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflector
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Pro osed
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Page 10 of 24
I Stage Storage Rating Curve I
446.8000 ft 0.0000 cf 452.4000 ft ]09.9560 c
446.9000 ft 1.9635 cf 4 2.000 ft 1 1 1.9195 c
447.0000 ft 3.9270 cf 4 2.6000 ft 1 13.8830 c
447.1000 ft 5.8905 cf 452.7000 ft 1 15.8465 c
447.2000 ft 7.8540 cf 452.8000 ft 1 17.8100 c
447.3000 ft 9.8175 cf 452.9000 ft 1 19.773 c
447.4000 ft 11.7810 cf 453.0000 ft 121.7370 c
447.5000 ft 13.7445 cf 453.1000 ft 123.7005 c
447.6000 ft 15.7080 cf 453.2000 ft 125.6640 c 1 '
447.7000 ft 17.6715 cf 453.3000 ft 127.6275 c
447.8000 ft 19.6350 cf 453.4000 ft 129.5910 c
447.9000 ft 21.5985 cf 453.5000 ft 131.5545 c
448.0000 ft 23.5620 cf 453.6000 ft 133.5180 c
448.1000 ft 25.5255 cf 453.7000 ft 135.4815 c
448.2000 ft 27.4890 cf 453.8000 ft 137.44 0 c
448.3000 ft 29.4525 cf 453.9000 ft 139.4085 c
0000
I
448.4000 ft 31.4160 cf 454.0000 ft 141.3720 c
448.5000 ft 33.3795 cf 454.1000 ft 143.3355 c I
448.6000 ft 3.3430 cf 454.2000 ft 145.2990 c
448.7000 ft 37.3065 cf 454.3000 ft 147.2625 c
448.8000 ft 39.2700 cf 454.4000 ft 149.2260 c
448.9000 ft 41.2335 cf 454.5000 ft 151.1895 c
449.0000 ft 43.1970 cf 454.6000 ft 153.1 30 c
449.1000 ft 45.1605 cf 454.7000 ft I55.1 165 c
449.2000 ft 47.1240 cf 454.8000 ft 1 7.0800 c
449.3000 ft 49.087 cf 454.9000 ft 159.0435 c
449.4000 ft 51.0510 cf 455.0000 ft 161.0070 c
449.5000 ft 53.0145 cf 455.1000 ft 162.9705 c
449.6000 ft 54.9780 cf 455.2000 ft 164.9340 c
449.7000 ft 56.9415 cf 455.3000 ft 166.8975 c
449.8000 ft 58.9050 cf 455.4000 ft 168.8610 c
449.9000 ft 60.8685 cf 455.5000 ft 170.8245 c
450.0000 ft 62.8320 cf 455.6000 ft 172.7880 c
450.1000 ft 64J955 cf 455.7000 ft 174.7515 c
450.2000 ft 66.7590 cf 455.8000 ft 176.7150 c
450.3000 ft 68.7225 cf 455.9000 ft 178.6785 c
450.4000 ft 70.6860 cf 456.0000 ft 180.6420 c
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Page 11 of 24
72.6495 cf 456.1000 ft 182.6055 c
450.6000 ft 74.6130 cf 456.2000 ft 184.5690 c
450.7000 ft 76.5765 cf 456.3000 ft 186.5325 c
450.8000 ft 78.400 cf 456.4000 ft 188.4960 c
450.9000 ft 80.5035 cf 456.5000 ft 190.4595 c
451.0000 ft 82.4670 cf 456.6000 ft 192.4230 c
451.1000 ft 84.4305 cf 456.7000 ft 194.3865 c
0000451.2000 ft 86.3940 cf 456.8000 ft 196.3500 c
451.3000 ft 88.3575 cf 4 6.9000 ft 198.3135 c
451.4000 ft 90.3210 cf 4 7.0000 ft 200.2770 c
451.5000 ft 92.2845 cf 457.1000 ft 202.2405 c
451.6000 ft 94.2480 cf 4572000 ft 204.2040 c
451.7000 ft 96.2115 cf 4 73000 ft 206.1675 c
451.8000 ft 98.1750 cf 457.4000 ft 208.1310 c
451.9000 ft 100.1385 c 457.5000 ft 210.0945 c
452.0000 ft 102.1020 c 457.6000 ft 212.0580 c
452.1000 ft 104.0655 c 457.7000 ft 214.0215 c
452.2000 ft 106.0290 c 457.8000 ft 215.9850 c
457.9100 ft 218.1452 c
Record Id: CB #6
Descri :Prototy e Record Increment 0.10 ft
Start E1.443.7600 ft Mati El. 453.2100 ft
Classification Manhole Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.63 0 sf
Condition Proposed
Stage Storage Rating Curve
443.7600 ft 0.0000 cf 448.5600 ft 94.2480 cf
443.8600 ft 1.9635 cf 448.6600 ft 96.2115 cf
443.9600 ft 3.9270 cf 448.7600 ft 98.1750 cf
444.0600 ft 5.8905 cf 448.8600 ft 100.1385 c
444.1600 ft 7.8540 cf 448.9600 ft 102.1020 c
444.2600 ft 9.8175 cf 449.0600 ft 104.0655 c
I444.3600 ft 11.7810 c 449.1600 ft 106.0290 c
444.4600 ft 13.7445 c 449.2600 ft 107.9925 c
A-8
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Page 12 of 24
444.5600 ft 15.7080 c 4493600 ft 109.9560 c
444.6600 ft 17.6715 c 449.4600 ft 1119195 c
444.7600 ft 19.6350 c 449.5600 ft 113.8830 c i
444.8600 ft 21.5985 c 449.6600 ft 115.8465 c
444.9600 ft 23.5620 c 449.7600 ft 117.8100 c
0000 I445.0600 ft 5.255 c 449.8600 ft 1 19.7735 c
445.1600 ft 27.4890 c 449.9600 ft 121.7370 c
0000
I
445.2600 ft 29.4525 c 450.0600 ft 123.7005 c I
445.3600 ft 31.4160 c 450.1600 ft 125.6640 c
445.4600 ft 33.3795 c 450.2600 ft 127.6275 c
445.5600 ft 3.3430 c 4 0.3600 ft 129.5910 c
445.6600 ft 37.3065 c 450.4600 ft 131.5545 c
445.7600 ft 39.2700 c 450.5600 ft 133.5180 c
445.8600 ft 41.2335 c 450.6600 ft 135.4815 c
445.9600 ft 43.1970 c 450.7600 ft 137.4450 c
446.0600 ft 4.1605 c 450.8600 ft 139.4085 c
446.1600 ft 47.1240 c 450.9600 ft 141.3720 c
446.2600 ft 49.0875 c 451.0600 ft 143.3355 c
446.3600 ft 51.0510 c 451.1600 ft 1452990 c
446.4600 ft 53.0145 c 451.2600 ft 147.2625 c
446.5600 ft 54.9780 c 451.3600 ft 149.2260 c
446.6600 ft 56.9415 c 451.4600 ft 151.1895 c
446.7600 ft 8.90 0 c 451.5600 ft 1 3.1530 c
446.8600 ft 60.8685 c 451.6600 ft 155.1 165 c
0000 i
446.9600 ft 62.8320 c 451.7600 ft 157.0800 c
447.0600 ft 64.7955 c 451.8600 ft 159.0435 c
447.1600 ft 66.7590 c 4 1.9600 ft 161.0070 c
447.2600 ft 68.7225 c 452.0600 ft 162.9705 c
447.3600 ft 70.6860 c 452.1600 ft 164.9340 c
447.4600 ft 72.6495 c 452.2600 ft 166.8975 c
447.5600 ft 74.6130 c 452.3600 ft 168.8610 c
447.6600 ft 76.5765 c 452.4600 ft 170.8245 c
447.7600 ft 78.5400 c 452.5600 ft 172.7880 c
447.8600 ft 80.5035 c 452.6600 ft 174.7515 c
447.9600 ft 82.4670 c 452.7600 ft 176J 150 c
448.0600 ft 84.4305 c 452.8600 ft 178.6785 c
448.1600 ft 86.3940 c 452.9600 ft 180.6420 c
448.2600 ft 88.3575 c 453.0600 ft 182.6055 c
A-8
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Page 13 of 24
u 90.3210 c 453.1600 ft 184.5690 c
453.2100 ft 185.5504 c
Record Id: CB #7
Descri :Protot e Record Increment 0.10 ft
Start EI.435.8500 ft Max El. 443.3500 ft
Classification Manhole Structure T'ype CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Proposed
Stage Stora e Ratin Curve
435.8500 ft 0.0001 cf 439.6 00 ft 74.6131 cf
135.9500 ft 1.9636 cf 439J500 ft 76.5766 cf
436.0500 ft 3.9271 cf 439.8500 ft 78.5401 cf
436.1500 ft 5.8906 cf 439.9500 ft 80.5036 cf
436.2500 ft 7.8541 cf 440.0500 ft 82.4671 cf
436.3500 ft 9.8176 cf 440.1500 ft 84.4306 cf
436.4500 ft 11 J811 c 440.2500 ft 86.3941 cf
436.5 00 ft 13.7446 c 440.3500 ft 88.3576 cf
436.6500 ft 15J081 c 440.4500 ft 90.3211 cf
436.7500 ft 17.6716 c 440.5500 ft 92.2846 cf
436.8500 ft 19.6351 c 440.6 00 ft 94.2481 cf
436.9500 ft 21.5986 c 440.7500 ft 96.2116 cf
437.0500 ft 23.5621 c 440.8500 ft 98.1751 cf
437.1500 ft 25.5256 c 440.9500 ft 100.1386 c
437.2500 ft 27.4891 c 441.0500 ft 102.1021 c
437.3500 ft 29.4526 c 441.1500 ft 104.0656 c
437.4500 ft 31.4161 c 441.2500 ft 106.0291 c
437.5500 ft 33.3796 c 441.3500 ft 107.9926 c
437.6500 ft 35.3431 c 441.4500 ft 109.9561 c I
437.7500 ft 37.3066 c 41.5500 ft 11 1.9196 c
437.8500 ft 39.2701 c 441.6500 ft 113.8831 c
437.9500 ft 41.2336 c 441.7500 ft 115.8466 c
438.0500 ft 43.1971 c 441.8500 ft 117.8101 c
438.1500 ft 45.1606 c 441.9500 ft 1 19.7736 c
4382500 ft 47.1241 c 442.0500 ft 121 J371 c
I
A-8
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Page 14 of 24
438.3500 ft 49.0876 c 442.1500 ft 123.7006 c
438.4500 ft 51.0 1 1 c 4 2.2500 ft 125.6641 c
438.5500 ft 3.0146 c 442.3500 ft 127.6276 c
438.6500 ft 54.9781 c 442.4500 ft 129.591 1 c
438.7500 ft 56.9416 c 442.5500 ft 131.5546 c
438.8 00 ft 8.9051 c 442.6500 ft 133.5181 c
438.9500 ft 60.8686 c 442.7500 ft 135.4816 c
439.0500 ft 62.8321 c 442.8500 ft 137.4451 c
439.1500 ft 64.7956 c 442.9 00 ft 139.4086 c
439.2500 ft 66J591 c 443.0 00 ft 141.3721 c
439.3500 ft 68.7226 c 443.1500 ft 143.3356 c
439.4 00 ft 70.6861 c 443.2500 ft 14.2991 c
443.3500 ft 147.2625 c
Record Id: EXISTING
Descri :Prototv e Record Increment 0.10 ft
Start EI.431.0800 ft Max EI. 438.0000 ft
Classification Manhole Structure Ty e CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Proposed
Stage Storage Rating Curve
431.0800 ft 0.0001 cf 434.5800 ft 68.7226 cf
431.1800 ft 1.9636 cf 434.6800 ft 70.6861 cf
431.2800 ft 3.9271 cf 434J800 ft 72.6496 cf
431.3800 ft 5.8906 cf 434.8800 ft 74.6131 cf
431.4800 ft 7.8541 cf 434.9800 ft 76.5766 cf
431.5800 ft 9.8176 cf 435.0800 ft 78.5401 cf
431.6800 ft 11.7811 c 435.1800 ft 80.5036 cf
431.7800 ft 13.7446 c 435.2800 ft 82.4671 cf
431.8800 ft 15.7081 c 435.3800 ft 84.4306 cf
431.9800 ft 17.6716 c 435.4800 ft 86.3941 cf
432.0800 ft 19.6351 c 435.5800 ft 88.3576 cf
432.1800 ft 21.5986 c 435.6800 ft 90.321 1 cf
432.2800 ft 23.5621 c 435.7800 ft 92.2846 cf
432.3800 ft 25.5256 c 435.8800 ft 942481 cf
A-8
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Page 15 of 24
432.4800 ft 27.4891 c 435.9800 ft 96.2116 cf
432.5800 ft 29.4526 c 436.0800 ft 98.1751 cf
432.6800 ft 31.4161 c 436.1800 ft 100.1386 c
432.7800 ft 33.3796 c 436.2800 ft 102.1021 c
432.8800 ft 35.3431 c 436.3800 ft 104.0656 c
432.9800 ft 37.3066 c 436.4800 ft 106.0291 c
433.0800 ft 39.2701 c 436.800 ft 107.9926 c
433.1800 ft 41.2336 c 436.6800 ft ]09.9561 c
433.2800 ft 43.1971 c 436.7800 ft 111.9196 c
433.3800 ft 45.1606 c 436.8800 ft 113.8831 c
433.4800 ft 47.1241 c 436.9800 ft 115.8466 c
433.5800 ft 49.0876 c 437.0800 ft I 17.8101 c
433.6800 ft 51.0511 c 437.1800 ft 119.7736 c
433.7800 ft 53.0146 c 437.2800 ft 121.7371 c
433.8800 ft 54.9781 c 437.3800 ft 123.7006 c
433.9800 ft 56.9416 c 437.4800 ft 125.6641 c
434.0800 ft 58.9051 c 437.5800 ft 127.6276 c
434.1800 ft 60.8686 c 437.6800 ft 129.5911 c
434.2800 ft 62.8321 c 437.7800 ft 131.5546 c
434.3800 ft 64.7956 c 437.8800 ft 133.5181 c
438.0000 ft 135.8745 c
Record Id: JNCT #1
Descrip:Prototype Record Increment 0.10 ft
Start El.453.8000 ft Max El. 463.8000 ft
Classification Catch Basin Structure Ty e CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Existing
Stage Storage Ratin Cur e
453.8000 ft 0.0000 cf 458.8000 ft 98.1750 cf
453.9000 ft 1.9635 cf 458.9000 ft 100.1385 c
454.0000 ft 3.9270 cf 459.0000 ft 102.1020 c
454.1000 ft 5.8905 cf 459.1000 ft 104.0655 c
454.2000 ft 7.8540 cf 459.2000 ft 106.0290 c
454.3000 ft 9.8175 cf 4593000 ft 107.9925 c
A-8
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Page 16 of 24
454.4000 ft 1 1.7810 c 459.4000 ft 1099 60 c
454.5000 ft 13.7445 c 459.5000 ft 111.9195 c
454.6000 ft 1.7080 c 459.6000 ft 113.8830 c
454.7000 ft 17.6715 c 459.7000 ft 115.8465 c
454.8000 ft 19.6350 c 459.8000 ft 117.8100 c
454.9000 ft 21.598 c 459.9000 ft 119.7735 c
455.0000 ft 23.5620 c 460.0000 ft 121.7370 c
455.1000 ft 25.5255 c 460.1000 fr 123J005 c
4 5.2000 ft 27.4890 c 460.2000 ft 125.6640 c
45.3000 ft 29.4525 c 460.3000 ft 127.6275 c
455.4000 ft 31.4160 c 460.4000 ft 129.5910 c
455.000 ft 33.3795 c 460.5000 ft 131.5545 c i
0000455.6000 ft 35.3430 c 460.6000 ft 133.5180 c
455J000 ft 37.306 c 460J000 ft 135.4815 c
455.8000 ft 39.?700 c 460.8000 ft 137.44 0 c II
455.9000 ft 41.233 c 460.9000 ft 139.408 c
456.0000 ft 43.1970 c 461.0000 ft 141.3720 c
456.1000 ft 45.1605 c 461.1000 ft 143.3355 c
00006.2000 ft 47.1240 c 461.2000 ft 145.2990 c I
456.3000 ft 49.0875 c 461.3000 ft 1472625 c
456.4000 ft 51.0510 c 461.4000 ft 149.2260 c
456.5000 ft 53A145 c 461.5000 ft 151.1895 c
456.6000 ft 54.9780 c 461.6000 ft 1 3.1530 c
456.7000 ft 56.9415 c 461 J000 ft 155.1 165 c
456.8000 ft 58.90 0 c 461.8000 ft 157.0800 c
456.9000 ft 60.868 c 461.9000 ft 159.0435 c
457.0000 ft 62.8320 c 462.0000 ft 161.0070 c
457.1000 ft 64.795 c 462.1000 ft 162.9705 c
457.2000 ft 66.7590 c 462.2000 ft 164.9340 c
457.3000 ft 68.7225 c 462.3000 ft 166.8975 c
457.4000 ft 70.6860 c 462.4000 ft 168.8610 c
457.5000 ft 72.6495 c 462.5000 ft 170.8245 c
457.6000 ft 74.6130 c 462.6000 ft 172.7880 c
457.7000 ft 76.5765 c 462.7000 ft 174.7515 c
4 7.8000 ft 78.5400 c 462.8000 ft 176.7150 c
457.9000 ft 80.5035 c 462.9000 ft 178.6785 c
458.0000 ft 82.4670 c 463.0000 ft 180.6420 c
458.1000 ft 84.4305 c 463.1000 ft 182.6055 c
A-8
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Page 17 of 24
86.3940 c 463.2000 ft 184.5690 c
4 8.3000 ft 88.3575 c 463.3000 ft 186.5325 c
4 8.4000 ft 90.3210 c 463.4000 ft 188.4960 c
458.000 ft 92.2845 c 463.5000 ft 190.4595 c
458.6000 ft 94.2480 c 463.6000 ft 192.4230 c
463.8000 ft 196.3500 c
Record Id: JNCT #2
Descri :Protot e Record Increment 0.10 ft
Start EI.453.5700 ft Max El. 458.5700 ft
Classification Catch Basin Structure Type CB-TYPE 1-48
Ent Ke Groove End w/Headwall (ke=0.20) Channelization Curved or Deflector
Catch l.5000 ft Bottom Area 19.6350 sf
Condition Existing
Stage Stora e Rating Curve
453.5700 ft 0.0001 cf 456.0700 ft 49.0876 c
453.6700 ft 1.9636 cf 456.1700 ft 51.0 11 c
453.7700 ft 3.9?71 cf 456.2700 ft 53.0146 c
453.8700 ft 5.8906 cf 456.3700 ft 54.9781 c
453.9700 ft 7.8541 cf 456.4700 ft 6.9416 c
454.0700 ft 9.8176 cf 456.5700 ft 58.9051 c
454.1700 ft 11.7811 c 456.6700 ft 60.8686 c
454.2700 ft 13.7446 c 456.7700 ft 62.8321 c
454.3700 ft 15.7081 c 456.8700 ft 64.7956 c
454.4700 ft 17.6716 c 456.9700 ft 66.7591 c
454.5700 ft 19.6351 c 457.0700 ft 68.7226 c
454.6700 ft 21.5986 c 457.1700 ft 70.6861 c
454.7700 ft 23.5621 c 457.2700 ft 72.6496 c
454.8700 ft 25.5256 c 4 7.3700 ft 74.6131 c
454.9700 ft 27.4891 c 457.4700 ft 76.5766 c
455.0700 ft 29.4526 c 457.5700 ft 78.5401 c
455.1700 ft 31.4161 c 457.6700 ft 80.5036 c
455.2700 ft 33.3796 c 457.7700 ft 82.4671 c
455.3700 ft 35.3431 c 457.8700 ft 84.4306 c
455.4700 ft 37.3066 c 457.9700 ft 86.3941 c
455.5700 ft 39.2701 c 458.0700 ft 883576 c
A-8
I
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Page 18 of 24
455.6700 ft 41.2336 c 458.1700 ft 90.321 1 c
455.7700 ft 43.1971 c 458.2700 ft 92.2846 c
455.8700 ft 45.1606 c 458.3700 ft 94.2481 c
458.5700 ft 98.1750 c
Record Id: JNCT #3
Descrip:Prototype Record Increment 0.10 ft
Start EI.449.4700 ft Max El. 459.1 100 ft
Classification Catch Basin Structure T - e CB-TYPE 1-48
Ent Ke Groove End /Headwall (ke=0.20) Channelization Curved or Deflecto
Catch 1.5000 ft Bottom Area 19.6350 sf
Condition Pro osed
Stage Storage Rating Curve
449.4700 ft 0.0000 cf 454.3700 ft 96.2115 cf
449.5700 ft 1.9635 cf 454.4700 ft 98.1750 cf
449.6700 ft 3.9270 cf 454.5700 ft 100.1385 c
449.7700 ft 5.8905 cf 454.6700 ft 102.1020 c
449.8700 ft 7.8540 cf 454.7700 ft 104.0655 c
449.9700 ft 9.817 cf 454.8700 ft 106.0290 c
4 0.0700 ft 11 J810 c 4 4.9700 ft 107.9925 c
450.1700 ft 13.7445 c 455.0700 ft 109.9560 c
450.2700 ft 15.7080 c 455.1700 ft 1 1 1.9195 c
450.3700 ft 17.6715 c 455.2700 ft 113.8830 c
450.4700 ft 19.6350 c 455.3700 ft 1 15.8465 c
450.5700 ft 21.5985 c 455.4700 ft 117.8100 c
450.6700 fi 23.5620 c 45.5700 ft 1 19.7735 c
450.7700 ft 25.5255 c 455.6700 ft 121.7370 c
450.8700 ft 27.4890 c 455.7700 ft 123.7005 c
450.9700 ft 29.4525 c 455.8700 ft 125.6640 c
451.0700 ft 31.4160 c 455.9700 ft 127.6275 c
451.1700 ft 33.3795 c 456.0700 ft 129.5910 c
451.2700 ft 35.3430 c 456.1700 ft 131.5545 c
451.3700 ft 37.3065 c 456.2700 ft 133.5180 c
451.4700 ft 39.2700 c 456.3700 ft 135.4815 c
451.5700 ft 41.2335 c 456.4700 ft 137.4450 c
451.6700 ft 43.1970 c 456.5700 ft 139.4085 c
A-8
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Page 19 of 24
r
451.7700 ft 45.1605 c 456.6700 ft 141.3720 c
451.8700 ft 47.1240 c 456.7700 ft 143.3355 c
451.9700 ft 49.0875 c 4 6.8700 ft 145.2990 c
452.0700 ft 51.0510 c 4 6.9700 ft 147.2625 c
452.1700 ft 53.0145 c 457.0700 ft 149.2260 c
452.2700 ft 54.9780 c 457.1700 ft 151.189 c
452.3700 ft 56.9415 c 457.2700 ft 153.1530 c
452.4700 ft 8.90 0 c 457.3700 ft 155.1165 c
4 2.5700 ft 60.8685 c 457.4700 ft 1 7.0800 c
f
452.6700 ft 62.8320 c 457.5700 ft 159.0435 c
452J700 ft 64.7955 c 457.6700 ft 161.0070 c
452.8700 ft 66.7590 c 457.7700 ft 162.9705 c
452.9700 ft 68.7225 c 457.8700 ft 164.9340 c
453.0700 ft 70.6860 c 457.9700 ft 166.8975 c
I 0000453.1700 ft 72.6495 c 458.0700 ft 168.8610 c
453.2700 ft 74.6130 c 458.1700 ft 170.8245 c
453.3700 ft 76.5765 c 458.2700 ft 172.7880 c
453.4700 ft 78.5400 c 458.3700 ft 174.7515 c
453.5700 ft 80.5035 c 458.4700 ft 176.7150 c
453.6700 ft 82.4670 c 458.700 ft 178.6785 c
453.7700 ft 84.4305 c 458.6700 ft 180.6420 c
453.8700 ft 86.3940 c 458J700 ft 182.6055 c
453.9700 ft 88.3575 c 458.8700 ft 184.5690 c
454.0700 ft 90.3210 c 458.9700 ft 186.5325 c
454.1700 ft 92.2845 c 4 9.0700 ft 188.4960 c
459.1100 ft 1892811 c
Record Id: P-001
Section Sha e: Circular
Uniform Flo v Method: Manning's Coefficient: OA100
Routing Method: Travel Time Translation
DnNode JNCT#1 U Node CB #1
Material Plastic Size 8" Diam
i
Ent Losses Groove End w/Headwall
i Length 24.0000 ft Slope 4.13%
U Invert 454.7900 ft Dn Invert 453.8000 ft
Conduit Constraints
r--
A-8
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Page 20 of 24
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50°/a 2.00% 3.00 ft
Dro across MH 0.0000 ft E Infil Rate 0.0000 in/hr
Up Invert 453.8000 ft Dn Invert 454.7900 ft
Match inverts.
DnNode JNCT #1 U Node CB #1
Record Id: P-002
Section Sha e: Circular
Uniform Flow Method: Manning's Coefficient: 0.0100
Routing Method: Travel Time Translation
DnNode JNCT#2 UpNode JNCT#1
I Material Plastic Size 8" Diam
Ent Losses Groove End w/Headwall
Len th 14.0000 ft Slope 1.64%
Up Invert 453.8000 ft Dn Invert 453.5700 ft
Conduit Constraints
Min Vel Max Vel Min Slo e Max Slo e Min Cover
2.00 fUs 15.00 ft/s 0.50% 2.00% 3.00 ft
Drop across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr
U Invert 453.5700 ft Dn Invert 453.8000 ft
Match inverts.
DnNode JNCT#2 UpNode JNCT#1
Record Id: P-003
Section Shape: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routin Method: Travel Time Translation
DnNode CB #2 U Node JNCT #2
Material Conc-Spun Size 8" Diam
Ent Losses Groove End w/Headwall
Len h 60.0000 ft Slo e 5.17%
Up Invert 453.5700 ft Dn Invert 450.4700 ft
Conduit Constraints
Min Vel Max Vel Min Slo e Max Slo e Min Cover
A-8
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Page 21 of 24
2.00 ft's 1.00 ftls 0.50% ?.00% 3.00 ft IIi
Dro across MH 0.0000 ft Eac/Infil Rate 0.0000 in/hr
U Invert 450.4700 ft Dn Invert 453.5700 ft
Match inverts.
DnNode CB #2 U Node JNCT #2
Record Id: P-004
Section Sha e: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routing Method: Travel Time Translation
DnNode JNCT#3 UpNode CB #2 I
Material Cono-S un Size 15" Diam I,
Ent Losses Groove End w/Headwall
Length 85.0000 ft Slope 0.46%
U Invert 449.8600 ft Dn Invert 449.4700 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50°/a 2.00% 3.00 ft
Dro across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr
Up Invert 449.4700 ft Dn Invert 449.8600 ft
Match inverts-
DnNode JNCT#3 U Node CB #2
Record Id: P-005 i
Section Sha e: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130 i
Routing Method: Travel Time Translation
DnNode CB #3 U Node JNCT#3 I
Material Conc-S un Size 15" Diam I
Ent Losses Groove End w/Headwall
Len th 85.0000 ft Slo e 0.67%
U Invert 449.4700 ft Dn Invert 448.9000 ft
Conduit Constraints
Min Vel Max Vel Min Slo e Max Slo e Min Cover
2.00 ft/s 15.00 ft/s 0.50°/a 2.00% 3.00 ft
A-8
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Page 22 of 24
IDrop across MH II0.0000 ft Ex/Infil Rate 0.0000 in/hr
U Invert 448.9000 ft Dn Invert 449.4700 ft
Match inverts.
DnNode CB #3 UpNode JNCT#3
Record Id: P-006
Section Shape: Circular
Uniform Flow Method: Mannin 's Coefficient: 0.0130
Routin Method: Travel Time Translation
DnNode CB #4 UpNode CB #3
Material Conc-Spun Size 15" Diam
Ent Losses Groove End w/Headwall
Len th 170.0000 ft Slo e 0.50%
Up Invert 448.9000 ft Dn Invert 448.0500 ft
Conduit Constraints
Min Vel Max Vel Min Slo e Max Slo e Min Cover
2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft
Dro across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr
U Invert 448.0500 ft Dn Invert 448.9000 ft
Match inverts.
DnNode CB #4 U Node CB #3 I,
Record Id: P-007
Section Shape: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routing Method: Travel Time Translation
DnNode CB #5 UpNode CB #4
Material Conc-S un Size 15" Diam
Ent Losses Groove End w/Headwall
Length 125.0000 ft Slope 1.00%
U Invert 448.0500 ft Dn Invert 446.8000 ft
Conduit Constraints
Min Vel MaY Vel Min Slope Max Slope Min Cover
2.00 ft s 15.00 ft/s 0.50% 2.00% 3.00 ft
Dro across MH 0.0000 ft E Infil Rate 0.0000 in/hr
Up Invert 446.8000 ft Dn Invert 448.0500 ft
A-8
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Page ?3 of 24
IMatch inverts.
DnNode CB #5 U Node CB #4
Record Id: P-008
Section Sha e: Circular
Uniform Flow Method: Mannin 's Coefficient: 0.0130
Routing Method: Travel Time Translation
DnNode CB #6 U Node CB #5
Material Conc-S un Size 15" Diam
Ent Losses Groove End w/Headwall
Length 200.0000 ft Slope 1.52%
U lnvert 446.8000 ft Dn Invert 443.7600 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slope Min Cover
2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft
Dro across MH 0.0000 ft E Infil Rate 0.0000 in/hr
Up Invert 443.7600 ft Dn Inver[ 446.8000 ft
Match inverts.
DnNode CB #6 U Node CB #5
Record Id: P-009
Section Sha e: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routing Method: Travel Time Translation
DnNode CB #7 U Node CB #6
Material Conc-Spun Size 15" Diam
Ent Losses Groove End w/Headwall
Len th 384.0000 ft Slo e 2.06%
U Invert 443.7600 ft Dn Invert 435.8500 ft
Conduit Constraints
Min Vel Max Vel Min Slo e Max Slo e Min Cover
2.00 ft/s 15.00 ft/s 0.50% 2.00°/a 3.00 ft
Drop across MH 0.0000 ft Ex/Infil Rate 0.0000 in/hr
U Invert 435.8500 ft Dn [nvert 443.7600 ft
Match im-erts.
DnNode CB #7 UpNode CB #6
A-8
file:U/Q:/2014/2140258/10_CIV/NON CAD!CALCS!Conveyance/20140716%20%20Con... 7/23/2014
Page 24 of 24
Record Id: P-010
Section Sha e: Circular
Uniform Flow Method: Manning's Coefficient: 0.0130
Routin Method: Travel Time Translation
DnNode EXISTING U Node CB #7
Material Conc-Spun Size 18" Diam
Ent Losses Groove End w/Headwall
Len th 222.0000 ft Slo e 2.60%
Up Invert 436.8500 ft Dn Invert 431.0800 ft
Conduit Constraints
Min Vel Max Vel Min Slope Max Slo e Min Cover
2.00 ft/s 15.00 ft/s 0.50°/a 2.00% 3.00 ft
Drop across MH 0.0000 ft E[nfil Rate 0.0000 in/hr
U Invert 431.0800 ft Dn Invert 436.8500 ft
Match inverts.
DnNode EXISTING UpNode CB #7
Licensed to: AHBL
A-8
file:l.IQ:12014I21402 8/10_CI V/NON_CAD/CALCS/Conveyance,20140716%20%20Con... 7/23,'2014
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This page left intentionally blank for double-sided printing.
ng County Districts and Development Conditions for parcel number 2... http://ww5.kin county.go;%kceisreports,dd_report.aspx?PII`=282305903
HOME NEWS SERVICES DIRECTORY CONTACTSearch Terms: Searc
KCGIS Center
www.KingCounty.gov/GIS
w._....__.
KCGIS Parcel Reports King County Districts and Development Conditions for parcel
Districts and Development r
Conditions Report 2823059034
Parcel number 2823059034 Draina e Lower Cedar RiverFindYourCouncilDistnct9
Address 16022116TH Basin e , "
Find Your Watershed AVE SE Lr4 t rsr:u Cedar River i Lake
5
111ash nqtott
4 °
a ' aKCGISCenterJurisdictionRenton1
Zipcode 98058 4?IA C clar-5arrsmarnish , , t
Kroll Map page 602 PLSS NW-28-23-5
Thomas Guide 656
page Latitude 47.45749 I
Longitude -122.18496
King County GIS Center
King Street Center
201 S. Jackson St.
Suite 706
Seattle.WA 98104
giscenter(c kingcounty.gov
a.5s9os N Electoral Districts
122.33136 W
i ;P;ct RNT 11-3590 Fire district does not apply
47° 35'56.72"Gi d:strict District 5,Qave Water district does not apply
122° 19'S2.90"U g£o g Sewer district does not apply206)477-1005
Water 8 Sewer Soos Creek Water 8 Sewer
district District
Congressional district 9 Parks&Recreation does not apply
Legislative district 11 district
School district Rentan#4D3 Hospital district Public Hospital District No.
Seattle school board distrid does not apply(not
in Seattle) Rural library district Rurel King County Library
King County planning and cr ti al reas designations
f;r:_C n+y ;ir:g NA,check with F '4 i.,;rEr xati r ar•a does not apply
jurisdiction R r21 towr% No
e'@IC•^v':"`:a'••i ccr:dit:o,s None Va e seryi e?^in r?, does not apply
Gcr p e:ns.ve P{ar um a:fs F 1PS z>:e 335
r an G-vw#ArEa Urban Tra sp..rt r rcu ren.c.y does not apply
7m.r3.itx._erv;ce Area does not apply '`a e v t
mmii 31#Y_P!^ning_,.fev Soos Creek Forest Production district? No
Coal mine hazards? None mapped AgricuRural Production district? No
Erosion hazards? None mapped C ,:_u j_ _;,^ r;,? None mapped
Landslide hazards? No e mapped 100-year flood plain? None mapped
v
Seismic hazards? None mapped Wetlands at this parcel? None mapped
t:?h€^:::a`a:a Sr rei>.er Non-Detect to 20.0
iurr32? PPm
Estimaoed fvsenic
Related resources
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King County Assessor:Quarter Section Map (PDF format requires Acrobat)
King County DPER: Perrnit Applications Report (for unincorporated areas onty)
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MAP NUMBER
53033C0983 F
K e=;,, MAP REVISEO:
MAY 16,1995
I I Federal Emergency Management Agency
I
Thls is an olficial copy ofa portlon of the abo e referenced 11ood map. R
was extracted usinp F-MIT On-Line. This map dces not reAect chanpes
Ior amendments which may ha e been made subsequent to the date onthe
title Wock. For the latent product iMormetlon about National Flood Ineurence
Propram 11ood mape check the FEMA Flood Map Store at vnvw.msc.fema.pov
A-12
I
1
This page left intentionally blank for double-sided printing.
Site Im rovement Bond Quantit Worksheet
II
p Y
Original bond computatlons prepared by:
Name:William Fierst ate:une 12,2014
PE Registration Number: Tel.#:(253)383-2422
Firm Name: AHBL
Address: 2215 N 30th St,Suite 300,Tacoma,WA 98403 Project No: 2140258.10
ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS
PERFORMANCE BOND*," PUBLIC ROAD&DRAINAGE
AMOUNT MAINTENANCE/DEFECT BOND',""
Stabilization/Erosion Sediment Control(ESC) A) $
Existing Right-of-Way Improvements B) $
Future Public Road Improvements 8 Drainage Facilities (C) $
Private Improvements D) $21,036.90
Construction Bond"Amount (A+g++D) = TOTAL (T) $21,036.90
Minimum bond'amount is$1000.
g+C)x
Maintenance/Defect Bond'Total 0.20= $
NAME OF PERSON PREPARING BOND'REDUCTION: Date.
NOTE: The word"bond"as used in this document means any financial guarantee acceptable to the City of Renton.
NOTE: All prices mclude labor,equipment,materials,overhead and profit. Prices are from RS Means data adjusted for the Seattle area
or from local sources if not included in the RS Means database.
DREQUIRED BOND"AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY RDSD
1
Page 1 of 1 Unit prices updated:2/12/02
W
Version:4/22/02
REF 8-H BOND QUANTITY WORKSHEET.xIs Report Date: 1/19/2010
This page left intentionally blank for double-sided printing.
Site Improvement Bond Quantity Worksheet
Existing Future Public Private Quantity Comp#eted
II, Righf-of-Way Right of Way tmprovements Bond Reduction)'
Draina e Facilities Qu2nt.
Unit Price llnit Quant. Cost Quant Cost Quant Cost Complete Cost
G N L!T'E fIS No.
Backfill 8 Compaction-embankment GI- 1 $ 5.62 CY 0 0.00 0 0.00 0 0.00 0 0.00
Backfill&Compaction-trench GI-2 $ 8.53 CY 0 0.00 0 0.00 0 0.00 0 0.00
Clear/Remove Brush, by hand GI-3 $ 0.36 SY 0 0.00 0 0.00 0 0.00 0 0.00
ClearinglGrubbinglTree Removal GI-4 $ 8,876.16 Acre 0 0.00 0 0.00 0.17 1,508.95 0 0.00
Excavation-bulk GI-5 $ 1.50 CY 0 0.00 0 0.00 6.73 10.10 0 0.00
Excavation-Trench GI-6 $ 4.06 CY 0 0.00 0 0.00 110 446.60 0 0.00
Fencing, cedar, 6' high GI-7 $ 18.55 LF 0 0.00 0 0.00 0 0.00 0 0.00
Fencing, chain link, vinyl coated, 6'high GI-8 $ 13.44 LF 0 0.00 0 0.00 0 0.00 0 0.00
Fencing, chain link, gate, vinyl coated, 2 GI-9 $ 1,271.81 Each 0 0.0o 0 0.00 0 0.00 0 0.00
Fencing, split rail, 3' high GI- 10 $ 12.12 LF 0 0.00 0 0.00 0 0.00 0 0.00
Fill&compact-common barrow GI- 11 $ 22.57 CY 0 0.0 0 0.00 0 0.00 0 0.00
Fill 8 compact-gravel base GI- 12 $ 25.48 CY 0 0.00 0 0.00 16 407.68 0 0.00
Fill &compact-screened topsoil GI - 13 $ 37.85 CY 0 0.00 0 0.00 0 0.00 0 0.00
Gabion, 12"deep, stone filled mesh GI - 14 $ 54.31 SY o 0.00 0 0.00 0 0.00 0 0.00
Gabion, 18"deep, stone filled mesh GI- 15 $ 74.85 SY 0 0.00 0 0.00 0 0.00 0 0.0
Gabion, 36"deep, stone filled mesh GI- 16 $ 132.48 SY 0 0.00 0 0.0 0 0.00 0 0.00
Grading, fine, by hand GI- 17 $ 2.02 SY 0 0.00 0 0.00 0 0.00 0 0.00
Grading, fine,with grader GI-18 $ 0.95 SY 0 0.00 0 0.00 143 135.85 0 0.00
Monuments, 3' long GI-19 $ 135.13 Each 0 0.00 0 0.00 0 0.00 0 0.00
Sensitive Areas Sign GI-20 $ 2.88 Each 0 0.00 0 0.00 0 0.00 0 0.00
Sodding, 1"deep, sloped ground GI-21 $ 7.46 SY 0 0.00 0 0.00 24 179.04 0 0.00
Surveying, line&grade GI-22 $ 788.26 Day 0 0.00 0 0.00 0 0.00 0 0.00
Surveying, lot location/lines GI-23 $ 1,556.64 Acre 0 0.00 0 0.00 0 0.00 0 0.00
Traffic control crew(2 flaggers) GI-24 $ 85.18 HR 0 0.00 0 0.00 0 0.00 0 0.00
Trail, 4"chipped wood GI-25 $ 7.59 SY 0 0.00 0 0.00 0 0.00 0 0.00
Trail, 4"crushed cinder GI-26 $ 8.33 SY 0 0.00 0 0.00 0 0.00 0 0.00
Trail, 4"top course GI-27 $ 8.19 SY 0 0.00 0 0.00 0 0.00 0 0.00
Wall, retaining, concrete GI -28 $ 44.16 SF 0 0.00 0 0.00 0 0.00 0 0.00
Wall. rockery GI -29 $ 9.49 SF 0 0.00 0 0.00 0 0.00 0 0.00
Page 2 of 7 SUBTOTAL 0.00 0.00 2,68821 0.00
A-13
Unit prices updated: 2/12/02
Version:4/22/02
REF 8-H BOND QUANTITY WORKSHEET.xIs Report Date: 1/19/2010
Site Improvement Bond Quantity Worksheet
Existing Future Public Private Band Reduction"
Right-of-way Right of Way lmproveme ts
8 Drainage Facilities Quant.
Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost
ROAOIMPROVEMENT No.
AC Gnnding 4 ,Ide rachine < 1000sy RI - 1 S 23 00 SY 0 0 00 0 0 00 0 0 00 0 0 00
AC Grindin , 4'wide machine 1000-2000 RI-2 $ 5.75 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Grinding,4'wide machine>2000sy RI-3 $ 1.38 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Removal/Disposal/Repair RI-4 $ 41.14 SY 0 0.00 0 0.00 0 0.00 0 0.00
Barricade, pe I RI-5 $ 30.03 LF 0.00 0 0.00 0 0.00 0.00
Barricade,type III ( Permanent) RI-6 $ 45.05 LF 0 0.00 0 0.00 0 0.00 0 0.00
Curb&Gutter, rolled RI-7 $ 13.27 LF 0 0.00 0 0.00 0 0.00 0 0.00
Curb&Gutter, vertical RI-8 $ 9.69 LF 0 0.00 0 0.00 0 0.00 0 0.00
Curb and Gutter, demolition and disposal RI-9 $ 13.58 LF 0 0.00 0 0.00 0 0.00 0 0.00
Curb, extruded asphalt RI-10 $ 2.44 LF 0 0.00 0 0.00 0 0.00 0 0.00
Curb, extruded concrete RI- 11 $ 2.56 LF 0 0.00 0 0.00 0 0.00 0 0.00
Sawcut, as halt, 3"depth RI- 12 $ 1.85 LF 0 0.00 0 0.00 5 9.25 0 0.00
Sawcut, concrete, per 1"depth RI-13 $ 1.69 LF 0 0.00 0 0.00 35 59.15 0 0.00
Sealant, asphalt RI- 14 $ 0.99 LF 0 0.00 0 0.00 0 0.00 0 0.00
Shoulder,AC, (see AC road unit price) RI- 15 $ - SY 0 0.00 0 0.00 0 0.00 0 0.00
Shoulder, ravel, 4"thick RI- 16 $ 7.53 SY 0 0.00 0 0.00 0 0.00 0 0.00
Sidewalk, 4"thick RI- 17 $ 30.52 SY 0 0.00 0 0.00 143 4,364.36 0 0.00
Sidewalk, 4"thick, demolition and dispos RI- 18 $ 27.73 SY 0 0.00 0 0.00 0 0.00 0 0.00
Sidewalk, 5"thick RI- 19 $ 34.94 SY 0 0.00 0 0.00 0 0.00 0 0.00
Sidewalk, 5"thick, demolition and dispos RI-20 $ 34.65 SY 0 0.00 0 0.00 0 0.00 0 0.00
Si n, handicap RI -21 $ 85.28 Each 0 0.00 0 0.00 0 0.00 0 0.00
Stripin , per stall RI -22 $ 5.82 Each 0 0.00 0 0.00 0 0.00 0 0.00
Striping,thermoplastic, (for crosswalk) RI-23 $ 2.38 SF 0 0.00 0 0.00 0 0.00 0 0.00
Striping,4"reflectorized line RI-24 $ 0.25 LF 0 0.00 0 0.00 0 0.00 0 0.00
Page 3 of 7 SUBTOTAL 0.00 0.00 4,432.76 0.00
A-13
Unit prices updated: 2/12/02
Version:4/22/02
REF 8-H BOND QUANTITY WORKSHEET.xIs Report Date: 1/19/2010
Site Im rovement B i W
II
p ond Quant ty orksheet
Exisfing Future Public Private Bond Reduction
Right-of-way Right of Way improvements
8 Drainage Facilifies Quant.
Unit Price Unit Quant. Cost Quant. Cosf Qu nt. Cost Compfete Cost
ROAD SURFACING {4"Rack=2.5 base&1 5"top eourse) For'J3 KCRS{6.5" Rock=5"base& 7.5"top eaurse)
For KCRS '93 (additional 2 5" basej add: RS- 1 S 3 60 SY 0 0 00 0 0 00 0 0 00 0 0.00
AC Overla , 1.5"AC RS-2 $ 7.39 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Overla , 2"AC RS-3 $ 8.75 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Road; 2", 4" rock, First 2500 SY RS-4 $ 17.24 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Road, 2",4"rock, Qty. over 2500SY RS-5 $ 13.36 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Road, 3",4"rock, First 2500 SY RS-6 $ 19.69 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Road, 3",4"rock, Qty. o er 2500 SY RS-7 $ 15.81 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Road, 5", First 2500 SY RS-8 $ 14.57 SY 0 0.00 0 0.00 0 0.00 0 0.00
AC Road, 5", Qty. Over 2500 SY RS-9 $ 13.94 SY 0 0.00 0 0.0 0 0.00 0 0.00
AC Road, 6", First 2500 SY RS- 1 $ 16.76 SY 0 0.40 0 0.00 0 0.00 0 0.00
AC Road, 6", Qty. Over 2500 SY RS- 11 $ 16.12 SY 0 0.00 0 0.0 0 0.00 0 0.00
Asphalt Treated Base, 4"thick RS- 1 $ 9.21 SY 0 0.00 0 0.00 0 0.00 0 0.00
Gravel Road, 4"rock, First 2500 SY S- 1 $ 11.41 SY 0 0.00 0 0.00 0 0.00 0 0.00
Gravel Road,4"rock, Qty. over 2500 SY RS- 1 $ 7.53 SY 0 0.00 0 0.00 0 0.00 0 0.00
PCC Road, 5", no base, over 2500 SY RS- 1 $ 21.51 SY 0 0.00 0 0.00 0 0.00 0 0.00
PCC Road, 6", no base, over 2500 SY RS- 1 $ 21.87 SY 0 0.00 0 0.00 0 0.00 0 0.00
Thickened Edge RS- 1 $ 6.89 LF 0 0.00 0 0.00 0 0.00 0 0.00
Page 4 of 7 SUBTOTAL 0.00 0.00 0.00 0.00
A- 13
Unit prices updated: 2/12/02
Version: 4/22/02
REF 8-H BOND QUANTITY WORKSHEET.xIs Report Date: 1/19/2010
Site Im rovement Bond Quantit WorksheetpY
Existing Future Public Private Bond Reductian"
Right-of-way Right of Way Improvements
Drainage Facitities Quant.
Unit Price Unit Quant. Cost Quant. Cost Quant Cost Complete Cost
DRAINAGE {CPP=Corrugated Plastic Pipe.N12 or Eq ivalent) For Cutvert prices, Average o#4'caver was assumed.Assume per#oratsd PVC is same pnce as soiid pipe.
Access Rcad R D D- 1 S 16 74 SY 0 0.00 0 0 00 0 0 00 0 0.00
Bollards-fixed D-2 $ 240.74 Each 0 0.00 0 0.00 0 0.00 0 0.00
Bollards-removable D-3 $ 452.34 Each 0 0.00 0 0.00 0 0.00 0 0.00
CBs include frame and lid)
CB Type I D-4 $ 1,257.64 Each 0 0.00 0 0.00 3 3,772.92 0 0.00
CB Type IL D-5 $ 1,433.59 Each 0 0.00 0 0.00 0 0.00 0 0.00
CB Type II,48"diameter D-6 $ 2,033.57 Each 0 0.00 0 0.00 0 0.00 0 0.00
for additional depth over 4' D-7 $ 436.52 FT 0 0.00 0 0.00 0 0.00 0 0.00
CB Type II, 54"diameter D-8 $ 2,192.54 Each 0 0.00 0 0.00 0 0.00 0 0.00
f r additional depth over 4' D-9 $ 486.53 FT 0 0.00 0 O.DO 0 0.00 0 0.00
CB Type II, 60"diameter D- 10 $ 2,351.52 Each 0 0.00 0 0.0o 0 0.00 0 0.00
for additional depth over 4' D- 11 $ 536.54 FT 0 0.00 0 0.00 0 0.00 0 0.00
CB Type II, 72"diameter D- 12 $ 3,212.64 Each 0.00 0 0.00 0 0.00 0 0.00
for additional depth over 4' D- 13 $ 692.21 FT 0 0.00 0 0.00 0 0.00 0 0.00
Through-curb Inlet Framework(Add) D- 14 $ 366.09 Each 0 0.0 0 0.00 0 0.00 0 0.00
Cleanout, PVC, 4" D- 15 $ 130.55 Each 0 0.00 0 0.00 0 0.00 0 0.0o
Cleanout, PVC, 6" D- 16 $ 174.90 Each 0 0.00 0 0.00 9 1,574.10 0 0.00
Cleanout, PVC, 8" D- 17 $ 224.19 Each 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, PVC,4" D- 18 $ 8.64 LF 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, PVC,6" D- 19 $ 12.60 LF 0 0.00 0 0.00 244 3,074.40 0 0.00
Culvert, PVC, 8" D-20 $ 13.33 LF 0 0.00 0 0.00 48 639.84 0 0.00
Culvert, PVC, 12" D-21 $ 21.77 LF 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, CMP, 8" D-22 $ 17.25 LF 0 0.00 0 0.40 0 0.00 0 0.00
Culvert, CMP, 12" D-23 $ 26.45 LF 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, CMP, 15" D-24 $ 32.73 LF 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, CMP, 18" D-25 $ 37.74 LF 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, CMP,24" D-26 $ 53.33 LF 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, CMP, 30" D-27 $ 71.45 LF 0 0.00 0 a.00 0 0.00 0 0.00
Culvert, CMP, 36" D-28 $ 112.11 LF 0 0.00 0 0.0a 0 0.00 0 0.00
Culvert, CMP,48" D-29 $ 140.83 LF 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, CMP,60" D-30 $ 235.45 LF 0 0.00 0 0.00 0 0.00 0 0.00
Culvert, CMP, 72" D-31 $ 302.58 LF 0 0.00 0 0.0 0 0.00 0 0.00
Page 5 of 7 SUBTOTAL 0.00 0.00 9,061.26 0.00
A-13
Unit prices updated: 2/12/02
Version:4/22/02
REF 8-H BOND QUANTITY WORKSHEET.xIs Report Date: 1/19/2010
Site Improvement Bond Quantity Worksheet
Existing Future Public Private Bond Reduction*
Right-of-way Right of Way improvements
DRAINAGE CONTINUED Drainage Facilities Quant.
No Uni#Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost
Culvert, Concrete, 8"D-32 S 21.02 LF 0 0 0 0 0 0 0 0
Culvert, Concrete, 12" D-33 $ 30.05 LF 0 0 0 0 0 0 0 0
Culvert, Concrete, 15" D-34 $ 37.34 LF 0 0 0 0 0 0 0 0
Culvert, Concrete, 18" D-35 $ 44.51 LF 0 0 0 0 0 0 0 0
Culve t, Concrete, 24" D-36 $ 61.07 LF 0 0 0 0 0 0 0 0
Culvert, Concrete, 30" D-37 $ 104.18 LF 0 0 0 0 0 0 0 0
Culvert, Concrete, 36" D-38 $ 137.63 LF 0 0 0 0 0 0 0 0
Culvert, Concrete, 42" D-39 $ 158.42 LF 0 0 0 0 0 0 0 0
Culvert, Concrete, 48" D-40 $ 175.94 LF 0 0 0 0 0 0 0 0
Culvert. CPP. 6" D-41 $ 10.70 LF 0 0 0 0 0 0 0 0
Culvert, CPP, 8" D-42 $ 16.10 LF 0 0 0 0 0 0 0 0
Culvert, CPP, 12" D-43 $ 20.70 LF 0 0 0 0 0 0 0 0
Culvert, CPP, 15" D-44 $ 23.00 LF 0 0 0 0 0 0 0 0
Culvert, CPP, 18" D-45 $ 27.60 LF 0 0 0 0 0 0 0 0
Culvert, CPP,24" D-46 $ 36.80 LF 0 0 0 0 0 0 0 0
Culvert, CPP, 30" D-47 $ 48.30 LF 0 0 0 0 0 0 0 0
Culvert, CPP, 36" D-48 $ 55.20 LF 0 0 0 0 0 0 0 0
Ditchin D-49 $ 8.08 CY 0 0 0 0 0 0 0 0
Flow Dispersal Trench (1,436 base+) D-50 $ 25.99 LF 0 0 0 0 0 0 0 0
French Drain (3'depth) D-51 $ 22.60 LF 0 0 0 0 0 0 0 0
Geotextile. laid in trench, polypropylene D-52 $ 2.40 SY 0 0 0 0 0 0 0 0
Infiltration pond testin D-53 $ 74.75 HR 0 0 0 0 0 0 0 0
Mid-tank Access Riser, 48"dia, 6'deep D-54 $ 1,605.40 Each 0 0 0 0 0 0 0 0
Pond Overflow Spillway D-55 $ 14.01 SY 0 0 0 0 0 0 0 0
Restrictor/Oil Separator, 12" D-56 $ 1,045.19 Each 0 0 0 0 0 0 0 0
Restrictor/Oil Separator, 15" D-57 $ 1,095.56 Each 0 0 0 0 0 0 0 0
Restrictor/Oil Separator, 18" D-58 $ 1,146.16 Each 0 0 0 0 0 0 0 0
Riprap, placed D-59 $ 39.08 CY 0 0 0 0 0 0 0 0
Tank End Reducer(36"diameter) D-60 $ 1,000.50 Each 0 0 0 0 0 0 0 0
Trash Rack, 12" D-61 $ 211.97 Each 0 0 0 0 0 0 0 0
Trash Rack, 15" D-62 $ 237.27 Each 0 0 0 0 0 0 0 0
Trash Rack, 18" D-63 $ 268.89 Each 0 0 0 0 0 0 0 0
Trash Rack. 21" D-64 $ 306.84 Each 0 0 0 0 0 0 0 0
Page 6 of 7 SUBTOTAL 0 0 0 0
A-13
Unit prices updated: 2/12/02
Version:4/22/02
REF 8-H BOND QUANTITY WORKSHEET.xIs Report Date: 1/19/2010
Site Improvement Bond Quantity Worksheet
Existing Future Public Private Bond Reduction`
Right-of-way Right of Way Improvements
Drainage Facilities Quant.
Untt Priee Unii Quant. Price Quant, Cosf Quant Cost Comptete Cost
PARKING LOT SURFACING
No.
2"AC,2"top course rock&4"borrow PL- 1 $ 15.84 SY 0 0 0 0 0 0
2"AC, 1.5" top course&2.5"base cour PL-2 $ 17.24 SY 0 0 0 0 0 0
4"select borrow PL-3 $ 4.55 SY 0 0 0 0 0 0
1.5"top course rock 8 2.5"base course PL-4 $ 11.41 SY 0 0 0 0 0 0
UTILITY POLES 8 STREET LIGHTING Utility pole€eloeatian costs must be accompanied by Franshise Utility's Gost Statement
Utility Pole(s) Relocation UP-1 Lump Sum 0 0
Street Light Poles w/L minaires UP-2 Each 0 0 0.00 0.00 0 0.00
i
zY 5 k. 3 { 5 :_
No.
WI - 1 0 0.00 0.00 0.00
WI-2 0 0.00 0.00 0.00
WI-3 0 0.00 0.00 0.00
WI-4 0 0.00 0.00 0.00
WI-5 0 0.00 0.00 0.00
WI-6 0 0.00 0.00 0.00
WI-7 0 0.00 0.00 0.00
WI-8 0 0.00 0.00 0.00
WI-9 0 0.00 0.00 0.00
vw-io 0 0.00 0.00 0.00
SUBTOTAL 0.00 0.00 0.00 0.00
SUBTOTAL(SUM ALL PAGES):0.00 0.00 16,182.23 0.00
30%CONTINGENCY 8 MOBILIZATION:O.OQ 0.00 4.854.67 0.00
GRANDTOTAL:0.00 0.00 21.036.90 0.00
COLUMN:B C D E
Page 7 of 7
A-13
Unit prices updated: 2/12/02
Version:4/22/02
REF 8-H BOND QUANTITY WORKSHEET.xis Report Date: 1/19/2010
KING COUNTY, WASHINGTON, SURFACE WA7'ER DESIGN MAVUAL
APPENDIX A
MAINTENANCE REQUIREMENTS FOR FLOW
CONTROL, CONVEYANCE, AND WQ FACILITIES
This appendix contains the maintenance requirements for the following typical stormwater control
facilities and components:
No. 1 —Detention Ponds(p.A-2)
No.2—Infiltrarion Facilities(p.A-3)
No. 3—Detention Tanks and Vaults(p.A-5)
No.4—Control Structure/Flow Restrictor(p.A-7)
No.5—Catch Basins and Manholes(p.A-9)
No.6—Conveyance Pipes and Ditches(p.A-11)
No. 7—Debris Barriers(e.g.,Trash Racks)(p. A-12)
No. 8—Energy Dissipaters(p.A- 13)
No.9—Fencing{p.A-14)
No. 10—GatesBollards/Access Barriers(p.A-15)
No. 11—Grounds(Landscaping)(p.A-16)
No. 12—Access Roads(p.A-17)
No. 13—Basic Biofiltration Swale(grass)(p.A-18)
No. 14—Wet Biofiltration Swale(p.A-19)
No. l 5—Filter Strip(p.A-20)
No. 16—Wetpond(p.A-21)
No. 17—Wetvault(p.A-23)
No. 18—Stormwater Wetland(p.A-24)
No. 19—Sand Filter Pond(p.A-26)
No.20—Sand Filter Vault(p.A-28)
No.21 —Stormfilter(Carnidge Type}(p.A-30)
No.22—Baffle OiUWater Separator(p.A-32)
No. 23—Coalescing Plate Oil/Water Separator(p.A-33) A-14
No. 24—Catch Basin Insert(p. A-35)
2009 Surface Water Design Manual—Appendix A 1/9/2009
A-1
APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,COi TVEYANCE,Ai ID WQ FACII,ITIES
NO. 5-CATCH BASINS AND MANHOLES
Maintenance Defect or Problem Condition When Malntenance is Needed Results Expected When
Component Maintenance is Perfortned
Structure Sediment Sediment exceeds 60°k of the depth from the Sump of catch basin contains no
bottom ofthe catch basin to the invert of the sediment.
lowest pipe into or out of the catch basin or is
within 6 inches of the invert of the lowest pipe
into or out of the catch basin.
Trash and debris Trash or debris of mare than'/:cubic foot which No Trash or debris blocking or
is located immediately in front of the catch basin potentially blocking entrance to
opening or is blocking capaaty of the catch basin catch basin.
by more than 10°.
Trash or debris in the catch basin that exceeds No Vash or debris in the catch basin.
the depth from the bottom of basin to invert the
lowest pipe into or out of the basin.
Dead animals or vegetation that could generate No dead animals or vegetation
odors that could cause complaints or dangerous present within catch basin.
gases(e.g.,methane).
Deposfts of garbage exceeding 1 cubic foot in No condition present which would
volume. attract or support the breeding of
insects or rodents.
Damage to frame Comer of frame extends more than'/.inch past Frame is even with curb.
andlor top slab curb face iMo the street(If applipble).
Top slab has hoies larger than 2 square inches or Top slab is free of holes and cracks.
cracks wider than'/.inch.
Frame not sitting flush on top slab,i.e., Frame is sitting flush on top slab.
separation of more than'/.inch of the frame from
the top slab.
Cracks in walls or Cracks wider than Y:inch and longer than 3 feet, Catch basin is sealed and
bottom any evidence of sal particles entering catch structurally sound.
basin through cracks,or maintenance person
judges that catch basin is unsound.
Cracks wider than'/inch and longer than 1 foot No cracks more than'/d inch wide at
at the joint of any inleUouUet pipe or any evidence the joint of inleUoutlet pipe.
of soil particles entering catch basin through
cradcs.
SettlemenU Catch basin has settled more than 1 inch or has Basin replaced or repaired to design
misalignment rotated more than 2 inches out of alignment standarcls.
Damaged pipe joints Cracks wider than'/:-inch at the joint of the No cracks more than'/.-inch wide at
inleUoutlet pipes or any evidence ofsoil entering the joint of inleUouUet pipes.
the catch basin at the joint of the inlet/outlet
pipes.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasdine,concrete slurties or paint. according to applicable regulations.
5ource control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
InIeUOutlet Pipe Sediment Sediment filling 20%or more of the pipe. Inlet/ouUet pipes Gear of sediment.
accumuladon
Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes.
pipes(indudes floatables and non-floatablesj.
Damaged Cracks wider than'/rinch at the joint of the No cracks more than'/.-inch wide at
inlet/ouUet pipes or any evidence of soil entering the joint of the inleUoutlet pipe.
at the joints of the inleUoutlet pipes.
A-14
2009 Surface Water Design Manual—Appendix A 1/9/2009
A-9
APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILI'TIES
NO. 5-CATCH BASINS AND MANHOLES
Maintenance Defect or Problem Condltion When Maintenance is Needed Results Expected When
Component Maintenance is PerFormed
Metal Grates Unsafe grate opening Grate with opening wider ihan'le inch. Grate opening meets design
Catch Basins) standards.
Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris.
of grate surface. footnote to guidelines for disposal
Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design
My open structure requires urgern standards.
maintenance.
Manhole Cover/Lid Coverllid not in place CoverAid is missing or only partially in place.CoverAid protects opening to
Any open structure requires urgent structure.
maintenance.
Lodcing mechanism Mechanism cannot be opened by one Mechanism opens with proper tools.
Not Working maintenance person with proper tools.Bolts
cannot be seated. Self-locking coverAid does not
work.
Coverllid difficutt to One maintenance person cannot remove CoverJlid can be removed and
Remove cover/lid after applying SO Ibs.of lift.reinstalled by one maintenance
person.
A-14
1/9/2009 2009 Surface Water Design Manual—Appendix A
A-]0
APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACII,ITIES
NO. 6-CONVEYANCE PIPES AND DITCHES
Mafntenance Defect or Problem Canditions When Malntenance Is Needed Results Expected When
Component Maintenance is Performed
Pipes Sediment 8 debris Accumulated sediment or debris that exceeds Water flows freely through pipes.
accumulation 20%of the diameter of the pipe.
Vegetation/roats Vegetationlroots that reduce free movement of Water flows freely through pipes.
water through pipes.
Contaminants and My evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations.
Source conVol BMPs implemented if
appropriate. No contaminants
present other than a surtace oil film.
Damage to protective Protective coatlng is damaged;rust or corrosion Pipe repaired or replaced.
coating or corrosion is weakening the structural integrity of any part of
pipe.
Damaged Any dent that decreases the cross section area of Pipe repaired or replaced.
pipe by more than 20%or is determined to have
weakened structural integrity of the pipe.
Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris deared from
square feet of ditch and slopes. ditches.
Sediment Accumulated sediment that exceeds 20%of the Ditch deaned/flushed of all sediment
accumulation design depth. and debris so that it matches design.
Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation
constitute a hazard to County personnel or the removed according to applicable
public. regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurties or paint. according to applicabfe regulations.
Source control BMPs implemented ff
appropriate. No contaminants
present other than a surface oil film.
Vegetation Vegetation that reduces free movement of water Water flows freely through ditches.
through ditches.
Erosion damage to My erosion observed on a ditch slope. Slopes are not eroding.
slopes
Rodc lining out of One layer or less of rock exists above native soil Repiace rocks to design standards.
place or missing(If area 5 square feet or more,any exposed native
Applicable) soil.
A-14
2009 Surface Water Design Manual—Appendix A 1/9/2009
A-1 I
APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES
NO. 11 -GROUNDS (LANDSCAPING)
Maintenance Defect or Probiem Conditions When Maintenance is Needed Results Expected When
Component Maintenance is Perfortned
Site Trash or litter My trash and debris which exceed 1 cubic foot Trash and debris deared from site,
per 1,OQo square feet(this is about equal to the
amount of trash it would take to fill up one
standard size office garbage can). In general,
there should be no visual evidence of dumping.
Noxious weeds Any no ous or nuisance vegetation which may Noxious and n isance vegetation
constitute a hazard to County personnel or the removed according to applicable
public. regulations, No danger of naxious
vegetation where County personnel
or the public might normally be.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to appiiqble regulations.
Source controi BMPs implemented if
appropriate. No conhaminants
present other than a surface oil film. il
Grasslgroundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a I
height height no greater than 6 inches.
Trees and Shrubs Hazard Any tree or limb of a tree identfied as having a No hazard trees in facility. I
potential to fall and cause property damage or
threaten human IHe. A hazard tree identified by
a qualified arbo ist must be removed as soon
as possible.
Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than 5%
broken which affect more than 25 0 of the total of total foliage with split or broken
foliage ofthe tree or shrub. limbs.
Trees or shrubs that have been blown down or No blown down vegeta6on or
knodced over. knocked over vegetation. Trees or
shn bs free of injury.
Trees or shrubs which are not adequately Tree or shrub in place and
supported or are leaning over,causing exposure adequately supported;dead or
ofthe roots.diseased trees removed.
II
A-14
1/9/2009 2009 Surface Water Design Manual-Appendix A
A-16
APPENDIX A MAIIVTENANCE REQUII2EMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES
NO.24-CATCH BASIN INSERT
Maintenance Defect.or Problem Conditions When Maintenance is Needed Resuks Expected When
Component Maintenance is Performed
Media lnsert sible Oil sible oil sheen passing through media Media inset replaced.
Insert does not fit Flow gets into catch basin without going through All flow goes through media.
catch basin properly media
Filter media plugged Filter media plugged. Flow through fitter media is normal.
Oil absorbent media Media oil saturated.Oil absorbent media replaced.
saturated
Water saturated Catc basin insert is saturated with water,which Insert replaced.
no longer has the qpacity to absorb.
Service life exceeded Regular interval replacement due to typical Media replaced at manufacturers
average life of inedia insert product,typically one recommended interval.
month.
Seasonal When storms occur and during the wet season. Remove,clean and replace or install
maintenance new insert after major storms,
monthly during the wet season or at
manufacturers recommended
interval.
A-14
2009 Surface Water Design Manual—Appendix A 1!9l2009
A-35
Appendix B
Cascade Elementary Topographic Map
Prepared by Townsend-Chastain &Assoc., Inc.
October 6, 1992
Cascade Elementary School Site Drainage Plan
Prepared by RoseWater Engineering, Inc.
June 14, 1994
j I
i
I
Technical Information Report O Q O OCascadeElementarySchool
Project No. 2140258.10
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