HomeMy WebLinkAboutTIR-4068
ENGINEERING REPORT
Technical Information Report
Southport Park Avenue Extension
Renton, WA
March 2021
PREPARED BY:
COUGHLIN PORTER LUNDEEN
801 Second Avenue, Suite 900
Seattle, WA 98104
P 206.343.0460
CONTACT / Tim Brockway, PE, LEED AP BD+C
DEVELOPMENT ENGINEERING
Brianne Bannwarth 05/20/2021
SURFACE WATER UTILITY
jfarah 05/20/2021
TABLE OF CONTENTS
TABLE OF CONTENTS ....................................................................................................................................... 1
I. PROJECT OVERVIEW .................................................................................................................................... 1
General Description .......................................................................................................................................... 1
Existing Conditions ........................................................................................................................................... 1
Proposed Drainage System .............................................................................................................................. 1
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 ................................................................................................................................... 5
Task 4 - Drainage System Description and Problem Descriptions ................................................................... 5
Upstream Analysis ........................................................................................................................................ 5
Downstream Analysis .................................................................................................................................... 6
Task 5 – Mitigation of Existing or Potential Problems....................................................................................... 6
IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ....................................... 7
Existing Site Hydrology (Part A) ....................................................................................................................... 7
Developed Site Hydrology (Part B) ................................................................................................................... 7
Performance Standards (Parts C) .................................................................................................................... 8
ON-site Best Management Practices (on-site BMPs) Part D ............................................................................ 9
Water Quality System (Part E) ........................................................................................................................ 10
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN .................................................................................. 11
Standard Requirements (based on 2017 RSWDM): ....................................................................................... 11
On-site Conveyance ....................................................................................................................................... 11
Existing Conditions: ..................................................................................................................................... 11
Developed Storm System Description: ....................................................................................................... 12
VI. SPECIAL REPORTS AND STUDIES ........................................................................................................... 14
VII. OTHER PERMITS ....................................................................................................................................... 15
VIII. CSWPPP ANALYSIS AND DESIGN .......................................................................................................... 16
Standard Requirements .................................................................................................................................. 16
ESC Plan Analysis and Design (Part A) ......................................................................................................... 17
SWPPS Plan Design (Part B) ......................................................................................................................... 17
IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ............................... 19
X. OPERATION AND MAINTENANCE MANUAL ............................................................................................ 20
Standard Maintenance.................................................................................................................................... 20
Appendix A – Figures ........................................................................................................................................ 1
Appendix B – Engineering Calculations .......................................................................................................... 2
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I. PROJECT OVERVIEW
GENERAL DESCRIPTION
The following Technical Information Report (TIR) provides the technical information and design analysis
required for developing the Drainage and Temporary Erosion and Sedimentation Control Plan (TESC) for the
Southport Park Avenue Extension Project. The stormwater design for the project was based on the
requirements set forth in the 2017 Renton Surface Water Design Manual (RSWDM) (See Figure 1 – Technical
Information Report Worksheet).
The Southport Park Avenue Extension Project is located within the City of Renton, situated north of the
existing intersection of Park Avenue and 757th Avenue. The proposed temporary road will extend north of
existing Park Avenue and will tie into the existing ground level parking garage tunnel on the Southport office
site. (See Figure 2 – Site Location Map). The site is in the NW ¼ of the NW ¼ of Section 8, Township 23
North, Range 5 East, Willamette Meridian.
Overall, the proposed roadway addition will include new paving, channelization, signage, and the installation of
storm conveyance infrastructure that will connect to an existing storm system on site. The existing site consists
of 1.08 acres of gravel and asphalt, all impervious area. The proposed conditions will consist of 0.72 acres of
asphalt and concrete sidewalk and 0.35 acres of hydroseed pervious area on fill slopes for the proposed Park
Avenue Road extension. The site discharges to the existing Southport property to the north, into a storm
conveyance system known as the “PSE Bypass” storm system, as named in the Southport Hotel project. The
existing PSE Bypass drainage system already accounts for the northern 0.44 acres of the proposed roadway.
Much of the western half of the existing PSE site currently drains to various storm structures that eventually
flow north and into the existing PSE Bypass pipe. The proposed Park Avenue Road will cause additional
impervious area to flow into the existing PSE Bypass pipe. An analysis has been performed to ensure that the
existing PSE Bypass pipe has sufficient capacity to convey stormwater from the additional impervious sarea.
Runoff from the site will be captured by catch basins and treated in a Contech Solutions StormFilter catch
basin prior to connection into the existing PSE drainage system. Soils for the area were mapped using the
King County Soil Survey maps (See Figure 3 – USDA Soil Survey Map), and a Geotechnical exploration has
been performed for the public portion of the Park Avenue extension to address slope and soil characteristics.
EXISTING CONDITIONS
The existing site consists of asphalt and gravel. Storm runoff currently drains south-southwest to north-
northeast. There is a total elevation change of approximately 3 feet across the site, from 25 feet in the
southwestern region to 22 feet in the northern region of the project limits. See Table 1 for the existing surface
conditions. The BNSF rail at the south end of the site sits at an elevation of approximately 28 feet.
PROPOSED DRAINAGE SYSTEM
The proposed site consists of asphalt roadway paving, concrete sidewalk placement, and a Contech Solutions
StormFilter catch basin. See Table 2 for the proposed surface conditions. According to Table 1.1.2.A of the
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2017 Renton Surface Water Design Manual (RSWDM), this project meets the criteria for a Full Drainage
Review, including water quality requirements. Per the 2017 RSWDM, since 100% of the runoff will directly
discharge to major receiving water body (Lake Washington) Basic Water Quality measures apply. All
conveyance on site will be designed according to Chapter 4 of the 2017 Renton Surface Water Design Manual
(RSWDM).
The project site lies within the City’s Existing Peak Flow Control basin. This project is therefore not required to
provide flow control for the replaced impervious area, provided the existing downstream system has sufficient
capacity to safely convey the added flows. The proposed roadway includes 0.72 acres of impervious area. The
existing PSE Bypass drainage system already takes 0.44 acres of the proposed roadway site area into
account for conveyance capacity. The remaining 0.28 acres of impervious area will be routed to the existing
PSE Bypass system via catch basins and a water quality catch basin. Based on City of Renton GIS data and
available survey data, this 0.28 acres of impervious area runoff is being redirected from the existing Boeing
drainage system located west of the site to the existing PSE Bypass drainage system. Both systems ultimately
drain to Lake Washington. See Southport Park Avenue Conveyance Analysis calculations, which indicate that
the existing PSE system has sufficient capacity to accommodate the additional flows generated by the portion
of the proposed roadway that the PSE system does not already account for. Storm runoff will be conveyed by
gutter flow to this series of catch basins and will then discharge to the new Contech StormFilter system (See
Figure 6A – Park Avenue Drainage Basins and Figure 6B – Drainage Basin Map). After being treated, all
runoff from the capture area and will be discharged into the existing PSE Bypass storm conveyance system
and ultimately discharged into Lake Washington.
PSE is proposing to redesign the stormwater utilities throughout the eastern half of the existing PSE site,
which they lease and is beyond the scope of this project. The existing storm structures along the western
edge of the existing PSE site will be removed where the proposed road conflicts. The drainage scheme
throughout the western half of the existing PSE site will remain with one existing catch basin having a slightly
modified connection to the next downstream catch basin.
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II. CONDITIONS AND REQUIREMENTS
This section will address the requirements set forth by the Core and Special Requirements listed in Chapter 1
of the City of Renton Surface Water Design Manual.
City of Renton Surface Water Design Manual Core Requirements:
1. Discharge at the Natural Location (1.2.1): This project proposes to redirect 0.28 acres of runoff
from what used to flow to the existing Boeing drainage system located west of the project site to the
existing PSE drainage system. Both areas tie into Lake Washington within a quarter mile of the site.
2. Off-site Analysis (1.2.2): Refer to Sections III and IV. A Level 1 downstream analysis has been
performed, as this project will discharge to Lake Washington.
3. Flow Control (1.2.3.1): Refer to Section IV. The project is located in a Peak Flow Control Area. Flow
control has not been provided for the proposed improvements, due to no expected increase in the 100
– year flow. The existing site is currently entirely impervious and the Park Avenue Road proposed
some impervious surfaces be replaced with pervious hydro-seeded slopes.
4. Conveyance System (1.2.4): Refer to Section V. Closed pipe systems, treatment catch basin and
extension connections have been provided for stormwater conveyance.
5. Erosion and Sedimentation Control (1.2.5): Refer to Section VIII and the demolition/TESC provided
as part of this submittal. The project will construct a series of sediment controls to address the
specific conditions at the site.
6. Maintenance and Operations (1.2.6): Refer to Section X. The proposed storm drainage system will
be privately owned, operated and maintained by SECO Development.
7. Financial Guarantees and Liability (1.2.7): The owner and contractor will obtain all necessary
permits and bonds prior to the beginning of construction.
8. Water Quality (1.2.8): Refer to Section IV. Water quality treatment for runoff from target pollution
generating surfaces will be provided by a Contech StormFilter system. See Section IV for more
information.
9. Onsite BMP (1.2.9): Refer to Section IV. Onsite BMP’s have been assessed to the maximum extent
possible. See Section IV for more information.
SPECIAL REQUIREMENTS:
Special Requirement #1. Other Adopted Area-Specific Requirements Section 1.3.1
• Critical Drainage Areas (CDAs): Not Applicable
• Master Drainage Plans (MDPs): There are no known master drainage plans covering this project site.
• Basin Plans (BPs): The project is located within the South Lake Washington – Renton drainage basin.
• Lake Management Plans (LMPs): Not Applicable
• Shared Facility Drainage Plans (SFDPs): Not Applicable
Special Requirement #2. Flood Hazard Area Delineation, Section 1.3.2: See Figure 9 for the 100-yr flood
zone. The site is within Zone X therefore no 100-yr flood plains have been delineated on the plans.
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Special Requirement #3. Flood Protection Facilities, Section 1.3.3: Not Applicable
Special Requirement #4. Source Controls, Section 1.3.4: See attached Activity Worksheet and Required
BMP’s.
Special Requirement #5. Oil Control, Section 6.1.5. Traffic counts in this section of roadway do not trigger
this requirement due to an anticipated WSDOT Average Daily Two-Way Traffic tabulation of 8,000 trips. No oil
control is required. However, the water quality StormFilter system will be a “proprietary facility” as categorized
under the High-Use menu (Section 6.1.5) and will remove targeted pollutants.
Special Requirement #6. Aquifer Protection Area. Section 1.3.6: See attached Aquifer Protection Map under
Appendix A. The site is not located in an Aquifer Protection Zone. Not applicable.
PROJECT SPECIFIC REQUIREMENTS:
There are no applicable project specific instructions.
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III. OFF-SITE ANALYSIS
TASK 1 – STUDY AREA DEFINITION AND MAPS
The Renton drainage basin map was used to verify that the site was fully in the Lake Washington South
drainage basin (See Figure 6B – Drainage Basin Map).
TASK 2 - RESOURCE REVIEW
a) Adopted Basin Plans Lake Washington South drainage basin
b) Floodplain/floodway (FEMA) Maps Site is not in the floodplain (See Figure 9)
c) Off-site Analysis Reports None
d) Sensitive Areas Folio No Sensitive Areas. See Figure 4 and Figure 10
e) Drainage Complaints and Studies No Drainage Complaints. See Figure 4.
f) Road Drainage Problems No Current Road Drainage Problems.
g) King County Soils Survey: See Figure 3 – USDA Soil Map
h) Wetland Inventory Maps: No Wetlands. See Figure 4
i) Migrating Rivers Study Not Applicable.
j) DOE’s Section 303d List of Polluted Waters See Section VIII, Part B of this report for Category
5 listings.
k) KC Designated Water Quality Problems Not Applicable.
l) City of Renton Critical Maps: See Figure 4 and Figure 10. Project is in a
seismic area.
TASK 3 - FIELD INSPECTION
Coughlin Porter Lundeen conducted site visits in preparing the project plans. Please refer to Task 4,
Downstream Analysis below for more information.
TASK 4 - DRAINAGE SYSTEM DESCRIPTION AND PROBLEM
DESCRIPTIONS
Runoff from the site will be conveyed through new and existing storm elements that discharge to Lake
Washington. The proposed road is designed to direct flows from the Park Avenue curb system to the catch
basin system, located on the west side of the road, which will collect and treat the runoff before discharging
into the existing PSE Bypass system. See Appendix A, Figure 11 – Offsite Analysis Map.
Upstream Analysis
Upstream of the proposed stormwater conveyance system is a limited segment of the public portion of the
Park Avenue extension. This segment of road will be included in the treatment volume for the conveyance
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design. Runoff will be conveyed to the most upstream catch basin on site through curb flow. See Figure 6A –
Park Avenue Drainage Basins, for reference.
Downstream Analysis
As delineated in red on Figure 11 – Offsite Analysis Map, the downstream analysis begins immediately after
the furthest downstream proposed pipe ties into the existing PSE Bypass system consisting of man-made
catch basins. Runoff generated on the project site discharges through a system of catch basins into an
underground drainage tunnel, and ultimately into Lake Washington. The distance from the PSE catch basin
this project proposes to tie into to Lake Washington is approximately 750 feet, see Figure 11 for downstream
conveyance route. No known drainage problems have been reported with this conveyance system.
The Park Avenue Extension project will add 0.28 acres of impervious area runoff to the existing PSE system.
This addition of impervious area can be accommodated by the existing PSE drainage system, see Southport
Park Avenue Extension Conveyance Analysis calculations. The additional basin area increases the impervious
area of the drainage basin (PSE #2a) from 1.26 acres to 1.54 acres, as indicated in the calculations.
TASK 5 – MITIGATION OF EXISTING OR POTENTIAL PROBLEMS
The proposed project will not increase the impervious area, as the existing site is fully asphalt & gravel-
covered, thus the project is not required to provide flow control facilities. The additional 0.28 acres of
impervious area to the existing PSE drainage system must work to assure no increased velocities are
experienced in the downstream system. Stormwater improvements include proposed treatment of 31,363
SF of pollution-generating impervious surface associated with the roadway. In order to provide treatment
for the project prior to the connection with PSE, a 1 – cartridge and 4 – cartridge Contech Stormfilter
systems have been proposed such that all PGIS from the proposed roadway is treated. The 4 – cartridge
StormFilter will capture runoff from 0.646 acres of impervious area and the 1 – cartridge StormFilter will
capture flows from 0.062 acres of impervious area. The 15 – minute off – line water quality flow rate for the 4 –
cartridge system is 0.0935 cfs and 0.0056 cfs for the 1 – cartridge facility. Both StormFilter water quality
facilities have been designed to safely accommodate the proposed flows. The pipe system itself has been
designed with 12 – inch and 18 – inch ductile iron pipes, allowing for adequate pipe capacity throughout the
system. See Conveyance Calculations, located in Appendix B: Engineering Calculations, which demonstrate
that the proposed stormwater flows the Park Avenue road expansion can be adequately conveyed by the
existing PSE Bypass pipe for the 25 – year storm.
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IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS
AND DESIGN
EXISTING SITE HYDROLOGY (PART A)
The disturbed area of 0.68 acres consists of existing asphalt and heavily compacted gravel that was used a
service yard for heavy PSE utilities. The site slopes generally south-southwest to north-northeast with about a
3-foot elevation change throughout. The site area conditions are illustrated in Figure 5A and summarized in
Table 1 below.
TABLE 1 - EXISTING SITE CONDITIONS AREA BREAKDOWN
DESCRIPTION AREA (SQUARE FEET) AREA (ACRES)
TOTAL PERVIOUS 0.0 0.0
TOTAL IMPERVIOUS 47,045 1.08
TOTAL DISTURBED
AREA 47,045 1.08
DEVELOPED SITE HYDROLOGY (PART B)
The developed site hydrology will not increase the amount of impervious area on site, as the existing site is
already completely impervious. The addition of roadway and drainage modifications will result in similar site
hydrology as it exists currently, before flowing into the proposed water quality treatment facilities and then into
the existing PSE conveyance system. Flow from the roadway being constructed will be captured and treated
before being discharged to the existing PSE system. The system will have 0.28 acres of impervious area
runoff added to it, as the existing system only accounts for 0.44 acres of the 0.72 – acre roadway and
sidewalk. See Figure 7– Proposed Site Conditions, for reference. Sheet flow runoff from the upstream
southern-most proposed catch basin will be directed to the catch basin via gutter flow and will then make its
way to the 4 – cartridge StormFilter treatment catch basin once it has been captured into the system.
Stormwater from the easternmost portion of the proposed roadway will be captured and treated by the 1 –
cartridge water quality facility.
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TABLE 2 - DEVELOPED SITE CONDITIONS AREA BREAKDOWN
DESCRIPTION AREA (SQUARE FEET) AREA (ACRES)
TOTAL PERVIOUS 15,682 0.36
NEW IMPERVIOUS
REPLACED IMPERVIOUS
0
31,363
0
0.72
TOTAL DISTURBED AREA 47,045 1.08
PERFORMANCE STANDARDS (PARTS C)
According to Section 1.2.3.1 (See Figure 8 - Flow Control Application Map) of the 2017 Renton Surface Water
Design Manual (RSWDM), this project is located within the Peak Flow Control area. Although this project lies
within a flow control basin, the project improvements are allowed to discharge directly to Lake Washington
without detention. Given that the project development satisfies all of the Direct Discharge Exemption criteria
(discussed below), flow control will not be required.
Direct Discharge Exemption Criteria:
A) The project site discharges to Lake Washington.
B) The conveyance system between the project site and the major receiving water (Lake Washington)
will extend to the ordinary high-water mark and will be comprised of manmade conveyance elements
(pipes) and will be within a private drainage easement.
C) The conveyance system will have adequate capacity to convey the 25-year peak flow (per Core
Requirement #4, Conveyance System) for the entire contributing drainage area.
D) The conveyance system will be adequately stabilized to prevent erosion
E) The direct discharge proposal will not divert flows from or increase flows to an existing wetland or
stream sufficient to cause a significant adverse impact.
To mitigate the impacts of storm and surface water runoff generated by new impervious surface onsite BMP’s
were proposed. Per Section 1.2.9 of the 2017 Renton Surface Water Design Manual (RSWDM) for
implementation of BMPs, an evaluation of the BMPs was done. These catch basins serve impervious area
only within the proposed Park Avenue extension roadway as shown per Figure 6A: Park Avenue Drainage
Basins and Figure 6B: Drainage Basin Map. SECO Development will assume maintenance of the Stormfilter
and catch basins as they comply with the drainage facility financial guarantee and liability requirements.
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ON-SITE BEST MANAGEMENT PRACTICES (ON-SITE BMPS) PART D
Onsite BMP’s have been assessed for this project to mitigate the impacts of storm and surface water runoff
generated by new impervious surfaces, existing impervious surfaces, and replaced impervious surface
targeted for mitigation. Due to direct discharge to Lake Washington, the LID performance standard does not
need to be met and bioretention, permeable pavement, and full dispersion are not required to be considered.
However, all other BMP’s have been assessed to the maximum extent possible per section 1.2.9 of the 2017
Renton Surface Water Design Manual (RSWDM). See assessment below.
On-site BMPs Assessment
SECTION
REFERENCE BMP DESCRIPTION ACTION
Section
C.2.2 Full Infiltration
Full Infiltration is infeasible because the
groundwater level is relatively high in this
area, estimated to be 5 feet below ground
surface per the Geotechnical Analysis.
Section
C.2.3 Limited Infiltration
Limited Infiltration is infeasible because the
groundwater level is relatively high in this
area, estimated to be 5 feet below ground
surface per the Geotechnical Analysis.
Section
C.2.4 Basic Dispersion
Basic Dispersion is infeasible because there is
not sufficient length to install a dispersion
trench, and there are no locations where a
“vegetated flowpath segment” of at least 25-
feet can be created.
Section
C.2.13 Soil Amendment Soil Amendment is feasible and has been
proposed for the site.
Section
C.2. Perforated Pipe
Perforated Pipe has been deemed infeasible
for the project because there are no buildings
proposed for the project, as perforated pipe is
typically used for draining roof area.
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WATER QUALITY SYSTEM (PART E)
Section 1.2.8.1(A) of the 2017 Renton Surface Water Design Manual (RSWDM) outlines the specific land uses
within Basic Water Quality Treatment areas which are subject to providing Enhanced Basic Water Quality
treatment. The project discharges to Lake Washington, a Basic Treatment Receiving Water, making it subject
to Basic Water Quality treatment for all new and replaced pollution generating impervious surfaces (PGIS).
This will be provided by the four-cartridge and one – cartridge Contech StormFilter system, which has a
General Use Level Designation from the Washington Department of Ecology for basic treatment and was
deemed suitable for this application. The water quality catch basin will be installed with the proposed road on
the north end, just prior to tie-in to the existing PSE catch basin in order to treat runoff prior to tie-in. The
proposed replaced impervious surface along the existing roadway to the north is currently served by a
separate water quality facility. An analysis into that water quality facility’s capacity is not required because it is
existing impervious surface that is to be replaced.
TABLE 3. WATER QUALITY TREATMENT AREA SUMMARY
NEW PGIS
(REQ. TREATMENT AREA)
PROPOSED TREATMENT AREA
(SEE FIG 4)
% DIFFERENCE
31,363 SF (0.72 AC) 31,363 SF (0.72 AC) 0%
According to capacity calculations provided by Contech Solutions LLC, the StormFilter catch basin can
accommodate all the flows this proposed roadway will generate in a 100-year storm. The proposed
StormFilters will capture runoff from 0.708 acres of impervious area. The treatment catch basin is designed to
capture offline flows of less than 1 cfs, and the project is designed with a water quality offline flow of 0.0935 cfs
for the 4 – cartridge water quality facility and 0.0056 cfs for the 1 – cartridge water quality facility. Therefore,
this StormFilter is designed to safely accommodate the proposed flows. See the water quality facility modeling
included in Appendix B.
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V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
This section discusses the criteria that will be used to analyze and design the proposed storm conveyance
system.
STANDARD REQUIREMENTS (BASED ON 2017 RSWDM):
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. All
stormwater conveyance will be designed such that the 100-year flow is conveyed without overtopping
the drive aisle or flooding any nearby buildings.
2. New pipe systems shall be designed with sufficient capacity to convey and contain (at
minimum) the 25 – year peak flow, assuming developed conditions for onsite tributary areas
and existing conditions for any offsite tributary areas. (1.2.4.1). The proposed pipe system has
been designed to convey and contain the 25 – year stormwater flows. See the Conveyance Report
included in Appendix B.
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. (1.2.4-2)(4.3.5-6). This project does
not propose a bridge.
4. Drainage ditches must convey the 25-year flow with 0.5 feet of freeboard and the 100-year flow
without overtopping. (1.2.4-2). This project does not propose open channel drainage ditches.
5. Floodplain Crossings must not increase the base flood elevation by more than 0.01 feet
[41(83.C)] and shall not reduce the flood storage volume [37(82.A)]. Piers shall not be
constructed in the FEMA floodway. [41(83.F.1)]. No work is being proposed within the base flood
elevation or within the FEMA floodway.
6. Stream Crossings shall require a bridge for class 1 streams that does not disturb or banks.
For type 2 and type 3 streams, open bottom culverts or other method may be used that will not
harm the stream or inhibit fish passage. [60(95.B)]. The project does not propose a stream
crossing.
7. Discharge at natural location is required and must produce no significant impacts to the
downstream property (1.2.1-1). The project will discharge to the existing PSE storm system and to
Lake Washington, ultimately.
ON-SITE CONVEYANCE
Existing Conditions:
Generally, stormwater runoff flows south to north by sheet flow to four existing PSE catch basins on site. This
runoff is taken offsite to the north through the Southport site to Lake Washington.
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Developed Storm System Description:
The provided conveyance analysis calculations and profile (See Figure 6E – Proposed Storm Conveyance
Profile Southport PSE Conveyance Analysis) demonstrate that the proposed storm system can adequately
convey and contain the stormwater flows associated with the 25 – year storm. The project will add roughly
0.72 acres of new PGIS associated with the proposed roadway. The northern portion of this site is already
accounted for as being conveyed into the existing PSE drainage system. This project proposes to add 0.28
acres to the existing system, once treated. Storm runoff will be conveyed by gutter flow to new catch basins
along the proposed roadway and will then be conveyed into the Contech StormFilter catch basin (See Figure
6A – Park Avenue Drainage Basins and Figure 6B – Drainage Basin Map). After being treated, all runoff from
the capture area and unaffected existing impervious area that currently drains elsewhere will be conveyed
through pipe to the PSE Bypass system and ultimately to Lake Washington.
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 the 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 3.10- Acceptable Uses of Runoff Computation Methods in the CORSWDM 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.
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 6A – Park Avenue
Drainage Basins. 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 a weighted
“C” value was found for each area, as seen in Figure 6C – Modified C Value Calculation, and entered into
SSA for each sub-basin.
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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 CORSWDM 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 for the 25 – year 24 – hour storm using Figure 3.2.1.C 25-Year 24
Hour Isopluvials within the 2017 CORSWDM. 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 CORSWDM, which are 2.66 and 0.65 for the 25-year 24 – hour storm respectively. Detailed calculations
showing the correlation between King County formulas and the SSA IDF curve can be seen below:
KCSWDM: IR,25-year,24-hour = PR * aR * TC –bR = (3.4in * 2.66 * 6.3 min -0.65) = 2.73 in/hr
SSA25-year,24-hour: i = B / (TC + D)E = (9.04in) / (6.3 min + 0) .65 = 2.73 in/hr
A node referred to as an outfall is also an important part of computing a conveyance analysis within SSA. The
proposed storm system connects to the existing PSE Bypass pipe, which eventually discharges into Lake
Washington. The eventual discharge to Lake Washington was modeled as the outfall for the conveyance
analysis. The Lake Washington water surface elevation fluctuates throughout the year based off controlled
release rates at the Ballard Locks determined by US Army Corp of Engineers. Based off previous projects in
the area, the outfall water surface elevation was set at 18.58’, which represents Lake Washington during the
summer months.
PSE has proposed to adjust the existing storm structures on their portion of the existing PSE site and have
performed an analysis into the expected peak flows from the entire PSE site into the existing PSE Bypass
pipe. Their analysis concluded that the 25 – year flow rate produced by the larger existing PSE site is
approximately 4.59 cfs. The 4.59 cfs 25 – year stormwater flow has been incorporated into the Southport
Conveyance Analysis by including it as an external inflow to CB#B0EX.
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VI. SPECIAL REPORTS AND STUDIES
Geotechnical Engineering Report, Park Avenue Extension
Prepared by Hart Crowser, Inc. (dated July 31, 2019)
15
VII. OTHER PERMITS
This project will require a City of Renton Civil Construction permit, City of Renton Land Use permit, and
NPDES permit.
16
VIII. CSWPPP ANALYSIS AND DESIGN
This section lists the requirements that will be used when designing the TESC plan for this site. A copy of the
Draft CSWPPP has been included at this time.
STANDARD REQUIREMENTS
Erosion/Sedimentation Plan shall include the following:
1. Clearing Limits
a. Clearing limits are noted on plans and will be implemented prior to any offsite impacts or
damage due to construction.
2. Cover Measures
a. During construction, temporary cover BMPs will be implemented to prevent erosion. The
project will meet wet season cover requirements.
3. Perimeter Protection
a. Silt Fence will be implemented around construction limits to preserve undisturbed areas.
4. Traffic Area Stabilization
a. The Contractor, per the plans, shall implement necessary BMP measures to ensure sediment
does not leave the site onto streets or adjacent properties.
5. Sediment Retention
a. Inlet protection will be implemented to prevent sediment from entering the existing drainage
system.
6. Surface Water Collection
a. Existing stormwater catch basins on-site that are proposed to remain will continue to operate
during construction to collect runoff.
7. Dewatering Control
a. Dewatering needs shall be monitored throughout construction.
8. Dust Control
a. Dust control BMPs will be implemented throughout construction.
9. Flow Control
a. Flow control is not required for the project as there will be no increase in impervious surface
coverage.
10. Control Pollutants
a. BMPs shall be implemented to prevent or treat contamination of stormwater runoff by pH
modifying sources. In addition, all waste materials from the site will be removed in a manner
that does not cause contamination of water.
11. Protect Existing and Proposed Stormwater facilities and On-Site BMPs
a. Inlet protection BMPs will be implemented on the site for existing and proposed catch basins
affected by construction.
12. Maintain Protective BMPs
17
a. BMPs listed in the SWPPP shall be maintained as needed through the project. As portions of
the project get completed, portions of the established BMPs shall be adjusted to other areas
of the project site until their completion.
13. Manage the Project
a. Proposed erosion and sediment control measures will be implemented throughout
construction.
ESC PLAN ANALYSIS AND DESIGN (PART A)
1. The Standard Requirements above indicate the overall ESC Plan approach and justify these methods
based on circumstances specific to the Southport Park Avenue extension project.
2. The proposed Contech StormFilter catch basin is the primary ESC and water quality treatment facility
that was analyzed for appropriateness to the project and sizing. Refer to Appendix B: Engineering
Calculations for the StormFilter catch basin sizing calculations.
3. The project site is currently flat with complete impervious surface coverage, giving it a low chance of
erosion risk. Once construction is complete, the road will be graded at a 2.0% slope, and the surface
off the road will grade down at a 3H:1V slope, which is consistent with City of Renton requirements.
This grading design will prevent on-site erosion.
4. Please refer to the SWPPP provided with this report for a full list of BMPs recommended for
construction. The special reports do not provide further BMP recommendation than what is discussed
in the SWPPP.
5. All techniques and products proposed for this project meet standards set in the Erosion and Sediment
Control Standards in Appendix D of the City of Renton Stormwater Design Manual.
SWPPS PLAN DESIGN (PART B)
The CSWPPP that has been included with this report identifies all activities that could contribute pollutants to
surface and storm water during construction.
The receiving water body for this project, Lake Washington, has 25 Category 5 listings:
Sediment – Assessment Unit ID: 47122F2D0_SW and 47122F2D0_SE
Chlordane – Assessment Unit ID: 47122G2D5, 47122F2B6, 47122F2B3
Dieldrin - Assessment Unit ID: 47122F2B3, 47122F2D5, 47122F2B6
Bacteria - Assessment Unit ID: 47122G2D7, 47122G2H0, 47122F2A0
4,4’-DDE – Assessment Unit ID: 47122H2B3, 47122F2B6, 47122G2D5
4,4’-DDD – Assessment Unit ID: 47122G2D5
Total Phosphorus – Assessment Unit ID: 47122H2E6
Total Chlordane – Assessment Unti ID: 47122G2D5
Polychlorinated Biphenyls (PCBs) – Assessment Unit ID: 47122G2D5, 47122H2B6,
47122F2B3, 47122H2E6
Mercury – Assessment Unit ID: 47122G2D5
2,3,7,8-TCDD (Dioxin) – Assessment Unit ID: 47122G2D5, 47122H2B6, 47122F2B3
The proposed water quality Contech StormFilter catch basins have been designed to treat water prior to
discharge into the existing PSE Bypass drainage system through Southport property and ultimately to Lake
18
Washington. The StormFilter catch basin has a General Use Level Designation (GULD), making it acceptable
to treat water for this site to meet the required Basic treatment.
19
IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION
OF COVENANT
A Bond Quantity Worksheet is included with this report.
20
X. OPERATION AND MAINTENANCE MANUAL
STANDARD MAINTENANCE
All facilities are to be maintained by SECO Development after a 2-year maintenance warranty. Sections of the
2017 Renton Surface Water Design Manual (RSWDM) under this section outline the Maintenance
Requirements for stormwater facilities and on-site BMPs have been included in this section on the following
pages for use by the City in the maintenance of the designed facilities.
21
MAINTENANCE STANDARDS FOR
PRIVATELY MAINTAINED DRAINAGE
FACILITIES AT SOUTHPORT
NO. 5 - CATCH BASINS
Maintenance
Component
Defect Conditions When Maintenance is
Needed
Results Expected
When Maintenance is
performed
General Trash &
Debris
(Includes
Sediment)
Trash or debris of more than 1/2 cubic
foot which is located immediately in front
of the catch basin opening or is blocking
capacity of the basin by more than 10%
No Trash or debris
located immediately in
front of catch basin
opening.
Trash or debris (in the basin) that
exceeds 1/3 the depth from the bottom of
basin to invert the lowest pipe into or out
of the basin.
No trash or debris in the
catch basin.
Trash or debris in any inlet or outlet pipe
blocking more than 1/3 of its height.
Inlet and outlet pipes
free of trash or debris.
Dead animals or vegetation that could
generate odors that could cause
complaints or dangerous gases (e.g.,
methane).
No dead animals or
vegetation present
within the catch basin.
Deposits of garbage exceeding 1 cubic
foot in volume
No condition present
which would attract or
support the breeding of
insects or rodents.
Structure
Damage to
Frame and/or
Top Slab
Corner of frame extends more than 3/4
inch past curb face into the street (If
applicable).
Frame is even with curb.
Top slab has holes larger than 2 square
inches or cracks wider than 1/4 inch
(intent is to make sure all material is
running into basin).
Top slab is free of holes
and cracks.
Frame not sitting flush on top slab, i.e.,
separation of more than 3/4 inch of the
frame from the top slab.
Frame is sitting flush on
top slab.
22
Maintenance
Components
Defect Condition When Maintenance is
Needed
Results Expected
When Maintenance is
Performed.
Cracks in
Basin Walls/
Bottom
Cracks wider than 1/2 inch and longer
than 3 feet, any evidence of soil
particles entering catch basin through
cracks, or maintenance person judges
that structure is unsound.
Basin replaced or
repaired to design
standards.
Cracks wider than 1/2 inch and longer
than 1 foot at the joint of any inlet/ outlet
pipe or any evidence of soil particles
entering catch basin through cracks.
No cracks more than
1/4 inch wide at the
joint of inlet/outlet pipe.
Sediment/
Misalignment
Basin has settled more than 1 inch or
has rotated more than 2 inches out of
alignment.
Basin replaced or
repaired to design
standards.
Fire Hazard Presence of chemicals such as natural
gas, oil and gasoline.
No flammable
chemicals present.
Vegetation Vegetation growing across and blocking
more than 10% of the basin opening.
No vegetation blocking
opening to basin.
Vegetation growing in inlet/outlet pipe
joints that is more than six inches tall
and less than six inches apart.
No vegetation or root
growth present.
Pollution Nonflammable chemicals of more than
1/2 cubic foot per three feet of basin
length.
No pollution present
other than surface film.
Catch Basin
Cover
Cover Not in
Place
Cover is missing or only partially in
place. Any open catch basin requires
maintenance.
Catch basin cover is
closed
Locking
Mechanism
Not Working
Mechanism cannot be opened by on
maintenance person with proper tools.
Bolts into frame have less than 1/2 inch
of thread.
Mechanism opens with
proper tools.
Cover Difficult
to Remove
One maintenance person cannot
remove lid after applying 80 lbs. of lift;
intent is keep cover from sealing off
access to maintenance.
Cover can be removed
by one maintenance
person.
Ladder Ladder Rungs
Unsafe
Ladder is unsafe due to missing rungs,
misalignment, rust, cracks, or sharp
edges.
Ladder meets design
standards and allows
maintenance person
safe access.
Metal Grates
(If Applicable)
Grate with opening wider than 7/8 inch. Grate opening meets
design standards.
23
Trash and
Debris
Trash and debris that is blocking more
than 20% of grate surface.
Grate free of trash and
debris.
Damaged or
Missing.
Grate missing or broken member(s) of
the grate.
Grate is in place and
meets design
standards.
24
NO. 9 - FENCING
Maintenance
Components
Defect Conditions When Maintenance is
Needed
Results Expected
When Maintenance is
Performed
General Missing or
Broken Parts
Any defect in the fence that permits
easy entry to a facility.
Parts in place to provide
adequate security.
Erosion Erosion more than 4 inches high and
12-18 inches wide permitting an
opening under a fence.
No opening under the
fence that exceeds 4
inches in height.
Wire Fences Damaged
Parts
Post out of plumb more than 6 inches. Post plumb to within 1-
1/2 inches.
Top rails bent more than 6 inches.
Top rail free of bends
greater than 1 inch.
Any part of fence (including post, top
rails) more than 1 foot out of design
alignment.
Fence is aligned and
meets design
standards.
Missing or loose tension wire.
Tension wire in place
and holding fabric.
Extension arm missing, broken, or
bent out of shape more than 1 1/2
inches.
Extension arm in place
with no bends larger
than 3/4 inch.
Deteriorated
Paint or
Protective
Coating
Part or parts that have a rusting or
scaling condition that has affected
structural adequacy.
Structurally adequate
posts or parts with a
uniform protective
coating.
25
NO. 6 - CONVEYANCE SYSTEMS (PIPES & DITCHES)
Maintenance
Component
Defect Conditions When Maintenance is
Needed
Results Expected
When Maintenance is
Performed
Pipes Sediment &
Debris
Accumulated sediment that exceeds
20% of the diameter of the pipe.
Pipe cleaned of all
sediment and debris.
Vegetation Vegetation that reduces free
movement of water through pipes.
All vegetation removed
so water flows freely
through pipes.
Damaged Protective coating is damaged; rust is
causing more than 50% deterioration
to any part of pipe.
Pipe repaired or
replaced.
Any dent that decreases the cross
section area of pipe by more than
20%.
Pipe repaired or
replaced.
Open Ditches Trash & Debris Trash and debris exceeds 1 cubic foot
per 1,000 square feet of ditch and
slopes.
Trash and debris
cleared from ditches.
Sediment Accumulated sediment that exceeds
20 % of the design depth.
Ditch cleaned/ flushed
of all sediment and
debris so that it matches
design.
Vegetation Vegetation that reduces free
movement of water through ditches.
Water flows freely
through ditches.
Erosion
Damage to
Slopes
See “Rain gardens” Standard No. 1 See “Rain gardens”
Standard No. 1
Rock Lining
Out of Place or
Missing (If
Applicable).
Maintenance person can see native
soil beneath the rock lining.
Replace rocks to design
standards.
Catch Basins See “Catch Basins: Standard No. 4 See “Catch Basins”
Standard No. 4
Debris
Barriers (e.g.,
Trash Rack)
See “Debris Barriers” Standard No.5 See “Debris Barriers”
Standard No. 5
26
NO. 11 - GROUNDS (LANDSCAPING)
Maintenance
Component
Defect Conditions When Maintenance is
Needed
Results Expected
When Maintenance is
Performed
General Weeds
(Nonpoisonous)
Weeds growing in more than 20% of
the landscaped area (trees and shrubs
only).
Weeds present in less
than 5% of the
landscaped area.
Safety Hazard Any presence of poison ivy or other
poisonous vegetation.
No poisonous vegetation
present in landscaped
area.
Trash or Litter Paper, cans, bottles, totaling more
than 1 cubic foot within a landscaped
area (trees and shrubs only) of 1,000
square feet.
Area clear of litter.
Trees and
Shrubs
Damaged Limbs or parts of trees or shrubs that
are split or broken which affect more
than 25% of the total foliage of the tree
or shrub.
Trees and shrubs with
less than 5% of total
foliage with split or
broken limbs.
Trees or shrubs that have been blown
down or knocked over.
Tree or shrub in place
free of injury.
Trees or shrubs which are not
adequately supported or are leaning
over, causing exposure of the roots.
Tree or shrub in place
and adequately
supported; remove any
dead or diseased trees.
27
NO. 12 - ACCESS ROADS/ EASEMENTS
Maintenance
Component
Defect Condition When Maintenance is
Needed
Results Expected
When Maintenance is
Performed
General Trash and
Debris
Trash and debris exceeds 1 cubic foot
per 1,000 square feet i.e., trash and
debris would fill up one standards size
garbage can.
Roadway free of debris
which could damage
tires.
Blocked
Roadway
Debris which could damage vehicle
tires (glass or metal).
Roadway free of debris
which could damage
tires.
Any obstruction which reduces
clearance above road surface to less
than 14 feet.
Roadway overhead clear
to 14 feet high.
Any obstruction restricting the access to
a 10 to 12 foot width for a distance of
more than 12 feet or any point
restricting access to less than a 10 foot
width.
Obstruction removed to
allow at least a 12 foot
access.
Road Surface Settlement,
Potholes, Mush
Spots, Ruts
When any surface defect exceeds 6
inches in depth and 6 square feet in
area. In general, any surface defect
which hinders or prevents maintenance
access.
Road surface uniformly
smooth with no evidence
of settlement, potholes,
mush spots, or ruts.
Vegetation in
Road Surface
Weeds growing in the road surface that
are more than 6 inches tall and less
than 6 inches tall and less than 6
inches apart within a 400-square foot
area.
Road surface free of
weeds taller than 2
inches.
28
NO. 12- WATER QUALITY FACILITIES
A.) Cartridge Filter Catch Basin
29
Maintenance
Component
Defect or
Problem
Condition When Maintenance is
Needed
Recommended
Maintenance to Correct
Problem
Facility –
General
Requirements
Life cycle Once per year, except mulch and trash
removal twice per year.
Facility is re-inspected and
any needed maintenance
performed
Contaminants
and pollution
Any evidence of contaminants or pollution
such as oil, gasoline, concrete slurries, or
paint
Materials removed and
disposed of according to
applicable regulations.
Source control BMPs
implemented if appropriate.
No contaminants present
other than a surface oil film.
Inlet Excessive
sediment or trash
accumulation
Accumulated sediments or trash impair free
flow of water into system
inlet should be free of
obstructions allowing free
distributed flow of water into
system
Mulch Cover Trash and
floatable debris
accumulation
Excessive trash and/or debris accumulation Minimal trash or other debris
on mulch cover. Mulch cover
raked level.
Proprietary Filter
Media/
Vegetation
Substrate
“Ponding” of
water on mulch
cover after mulch
cover has been
maintained
Excessive fine sediment passes the mulch
cover and clogs the filter media/vegetative
substrate
Stormwater should drain
freely and evenly through
mulch cover. Replace
substrate and vegetation
when needed
Plants not
growing or in
poor condition
Soil/mulch too wet, evidence of spill,
incorrect plant selection, pest infestation,
and/or vandalism to plants
Plants should be healthy
and pest free
Damaged Pipes Any part of the pipes that are crushed,
damaged due to corrosion and/ or settlement.
Pipe repaired and/ or
replaced.
Access Cover
Damaged/ Not
Working
Cover cannot be opened, one person cannot
open the cover, corrosion/ deformation of
cover.
Cover repaired to proper
working specifications or
replaced.
Vault Structure
Includes Cracks
in Wall, Bottom,
Damage to Frame
and/ or Top Slab
Cracks wider than 1/2-inch and any evidence
of soil particles entering the structure through
the cracks, or maintenance/ inspection
personnel determines that the vault is not
structurally sound.
Vault replaced or repaired to
design specifications.
Structure Structure has
visible cracks
Cracks wider than ½ inch Evidence of soil
particles entering the structure through the
cracks
Structure is sealed and
structurally sound
Appendix A – Figures
Figures
Figure 1 Technical Information Report Worksheet
Figure 2 Site Location Map
Figure 3 USGS Soil Map
Figure 4 Sensitive Areas Map
Figure 5A Existing Site Conditions
Figure 5B Existing Site Conditions
Figure 6A Park Avenue Drainage Basins
Figure 6B Drainage Basin Map
Figure 6C Modified C Value Calculation
Figure 6D Proposed Additional Impervious Area Map
Figure 7 Proposed Site Conditions
Figure 8 Flow Control Application Map
Figure 9 FEMA Map
Figure 10 Aquifer Protection Map
Figure 11 Offsite Analysis
CITY OF RENTON SURFACE WATER DESIGN MANUAL
2017 City of Renton Surface Water Design Manual 12/12/2016 8-A-1
REFERENCE 8-A
TECHNICAL INFORMATION REPORT (TIR)
WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER Part 2 PROJECT LOCATION AND
DESCRIPTION
Project Owner _____________________________
Phone ___________________________________
Address __________________________________
_________________________________________
Project Engineer ___________________________
Company _________________________________
Phone ___________________________________
Project Name __________________________
CED Permit # ________________________
Location Township ________________
Range __________________
Section _________________
Site Address __________________________
_____________________________________
Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS
Land Use (e.g., Subdivision / Short Subd.)
Building (e.g., M/F / Commercial / SFR)
Grading
Right-of-Way Use
Other _______________________
DFW HPA
COE 404
DOE Dam Safety
FEMA Floodplain
COE Wetlands
Other ________
Shoreline Management
Structural Rockery/Vault/_____
ESA Section 7
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report Site Improvement Plan (Engr. Plans)
Type of Drainage Review
(check one):
Date (include revision
dates):
Date of Final:
Full
Targeted
Simplified
Large Project
Directed
____________________________________
__________________
Plan Type (check
one):
Date (include revision
dates):
Date of Final:
Full
Modified
Simplified
____________________________________
__________________
Figure 1 - TIR Worksheet
SECO Development
(425) 282-5833
1083 Lake Washington Blvd, Suite 50
Renton, WA 98056
Tim Brockway, P.E.
Coughlin Porter Lundeen
(206) 343-0460
Southport Park Avenue Extension
23N
5E
8
North of existing Park Avenue
(extension of City Park Avenue
extension)
3/29/2021
3/29/2021
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-2
Part 6 SWDM ADJUSTMENT APPROVALS
Type (circle one): Standard / Blanket
Description: (include conditions in TIR Section 2)
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
Approved Adjustment No. ______________________ Date of Approval: _______________________
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes / No
Start Date: _______________________
Completion Date: _______________________
Describe: _________________________________
_________________________________________
_________________________________________
Re: SWDM Adjustment No. ________________
Part 8 SITE COMMUNITY AND DRAINAGE BASIN
Community Plan: ____________________________________________________________________
Special District Overlays: ______________________________________________________________
Drainage Basin: _____________________________________________________________________
Stormwater Requirements: _____________________________________________________________
Part 9 ONSITE AND ADJACENT SENSITIVE AREAS
River/Stream ________________________
Lake ______________________________
Wetlands ____________________________
Closed Depression ____________________
Floodplain ___________________________
Other _______________________________
_______________________________
Steep Slope __________________________
Erosion Hazard _______________________
Landslide Hazard ______________________
Coal Mine Hazard ______________________
Seismic Hazard _______________________
Habitat Protection ______________________
_____________________________________
Figure 1 - TIR Worksheet
Lake Washington South Drainage Basin
Flow control not required. No increase in impervious area. Basic WQ required.
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3
Part 10 SOILS
Soil Type
______________________
______________________
______________________
______________________
Slopes
________________________
________________________
________________________
________________________
Erosion Potential
_________________________
_________________________
_________________________
_________________________
High Groundwater Table (within 5 feet)
Other ________________________________
Sole Source Aquifer
Seeps/Springs
Additional Sheets Attached
Part 11 DRAINAGE DESIGN LIMITATIONS
REFERENCE
Core 2 – Offsite Analysis_________________
Sensitive/Critical Areas__________________
SEPA________________________________
LID Infeasibility________________________
Other________________________________
_____________________________________
LIMITATION / SITE CONSTRAINT
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Additional Sheets Attached
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Threshold Discharge Area:
(name or description)
Core Requirements (all 8 apply):
Discharge at Natural Location Number of Natural Discharge Locations:
Offsite Analysis Level: 1 / 2 / 3 dated:__________________
Flow Control (include facility
summary sheet)
Standard: _______________________________
or Exemption Number: ____________
On-site BMPs: _______________________________
Conveyance System Spill containment located at: _____________________________
Erosion and Sediment Control /
Construction Stormwater Pollution
Prevention
CSWPP/CESCL/ESC Site Supervisor: _____________________
Contact Phone: _________________________
After Hours Phone: _________________________
Figure 1 - TIR Worksheet
loose sandy silt
Southport Park Avenue Extension Site
1 (existing PSE pipe)
N/A
TBD
TBD
TBD
1.2.3.1A
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4
Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet
per Threshold Discharge Area)
Maintenance and Operation Responsibility (circle one): Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and Liability Provided: Yes / No
Water Quality (include facility
summary sheet)
Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog
or Exemption No. _______________________
Special Requirements (as applicable):
Area Specific Drainage
Requirements
Type: SDO / MDP / BP / Shared Fac. / None
Name: ________________________
Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None
100-year Base Flood Elevation (or range): _______________
Datum:
Flood Protection Facilities Describe:
Source Control
(commercial / industrial land use)
Describe land use:
Describe any structural controls:
Oil Control High-Use Site: Yes / No
Treatment BMP: _________________________________
Maintenance Agreement: Yes / No
with whom? _____________________________________
Other Drainage Structures
Describe:
Figure 1 - TIR Worksheet
N/A
Contech StormFilter WQ catch basin utilized prior to tie in with existing PSE storm system
Temporary road infrastructure, drainage modifications
Contech StormFilter Catch
Basin, COR catch basins
Catch basins and Contech StormFilter Catch Basin designed to pass
100-yr storm peak safely
REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-5
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
Clearing Limits
Cover Measures
Perimeter Protection
Traffic Area Stabilization
Sediment Retention
Surface Water Collection
Dewatering Control
Dust Control
Flow Control
Control Pollutants
Protect Existing and Proposed BMPs/Facilities
Maintain Protective BMPs / Manage Project
MINIMUM ESC REQUIREMENTS
AFTER CONSTRUCTION
Stabilize exposed surfaces
Remove and restore Temporary ESC Facilities
Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore
operation of BMPs/Facilities as necessary
Flag limits of sensitive areas and open space
preservation areas
Other _______________________
Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch)
Flow Control Type/Description Water Quality Type/Description
Detention
Infiltration
Regional Facility
Shared Facility
On-site BMPs
Other
________________
________________
________________
________________
________________
________________
Vegetated Flowpath
Wetpool
Filtration
Oil Control
Spill Control
On-site BMPs
Other
________________
________________
________________
________________
________________
________________
________________
Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS
Drainage Easement
Covenant
Native Growth Protection Covenant
Tract
Other ____________________________
Cast in Place Vault
Retaining Wall
Rockery > 4′ High
Structural on Steep Slope
Other _______________________________
Figure 1 - TIR Worksheet
Contech StormFilter
Outflow to Lake
Washington
REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-6
Part 17 SIGNATURE OF PROFESSIONAL ENGINEER
I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my
knowledge the information provided here is accurate.
____________________________________________________________________________________ Signed/Date
Figure 1 - TIR Worksheet
Figure 2 - Site Location
Project Site
Southport Park Avenue Extension
C180194-03 January 2021
Soil Map—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/15/2019
Page 1 of 352609305260990526105052611105261170526123052612905260930526099052610505261110526117052612305261290559660559720559780559840559900559960560020560080560140560200
559660 559720 559780 559840 559900 559960 560020 560080 560140 560200
47° 30' 8'' N 122° 12' 28'' W47° 30' 8'' N122° 12' 1'' W47° 29' 56'' N
122° 12' 28'' W47° 29' 56'' N
122° 12' 1'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84
0 100 200 400 600
Feet
0 35 70 140 210
Meters
Map Scale: 1:2,630 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
Figure 3 - USDA Soil Survey Map
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 14, Sep 10, 2018
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
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/15/2019
Page 2 of 3
Figure 3 - USDA Soil Survey Map
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
Ur Urban land 24.9 100.0%
Totals for Area of Interest 24.9 100.0%
Soil Map—King County Area, Washington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/15/2019
Page 3 of 3
Figure 3 - USDA Soil Survey Map
36,112 3,009
City of Renton Sensitive Areas Map
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.
5/16/2019
Legend
2,04601,023
THIS MAP IS NOT TO BE USED FOR NAVIGATION
Feet
Notes
2,046
WGS_1984_Web_Mercator_Auxiliary_Sphere
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Erosion Hazard - High
Special Flood Hazard Areas (100
year flood)
Landslide
Very High
High
Moderate
Unclassified
Wetlands
Seismic Hazard Areas
Faults
Streets
Parks
Waterbodies
Designated Neighborhoods
Map
Extent2010
Map
Project Site
Figure 4 - Sensitive Areas Map
FIGURE 5A
EXISTING SITE CONDITIONS
1" : 60'
PROPOSED SITE CONDITIONS
Description Quantity Unit
IMPERVIOUS 1.08 ac
SOUTHPOST PSE SHUFFLETON
C180194-03 3/29/2021
Figure 5B - Existing Southport Conditions
Notes:
1These sub-basin areas are based on existing PSE site conditions.
Scale: 1" = 200'
Lake Washington
1.26 ac
1.32 ac
1.36 ac
PSE#4
PSE#3
PSE#2
PSE#1
Existing Drainage Tunnel
PSE#2a
PSE Property Line
Project Site
Southport Park Aveue Extension
C180194-03 May 2019
FIGURE 6A
PARK AVENUE DRAINAGE BASINS
SOUTHPORT PSE CONVEYANCE ANALYSIS
CB#C1
SOLID LID
CB#B0 EX
BASED ON PES SITE IMPROVMENTS
ANALYSIS, 4.59 CFS ASSUMED TO BE 25
YR PEAK FLOW FROM PSE SITE
CB#A3
SOLID LIDCB#A2
SOLID LID
CB#A1
SOLID LID
1" : 60'
CB#C2
WQ FACILITY
EX 18" PSE
BYPASS
PIPE
DRAINAGE BASIN SUMMARY
Description Quantity Unit
CB#A5 2,306 sf
CB#A6 1,363 sf
CB#A7 1,664 sf
CB#A8 4,252 sf
CB#A9 4,249 sf
CB#A10 3,161 sf
CB#A11 3,131 sf
CB#A12 2,574 sf
CB#A13 3,686 sf
CB#A13 105 sf
CB#A14 1,739 sf
CB#A14 222 sf
CB#C2 2,682 sf
CB#A6 CB#A7 CB#A8 CB#A9 CB#A10
CB#A11
CB#A12
CB#A13
CB#A14
CB#A4
SOLID LID
CB#A5
WQ
FACILITY
SOUTHPORT PSE SHUFFLETON SITE
1/25/2021
72,224 6,019
City of Renton Drainage Basin Map
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.
5/15/2019
Legend
4,09302,046
THIS MAP IS NOT TO BE USED FOR NAVIGATION
Feet
Notes
4,093
WGS_1984_Web_Mercator_Auxiliary_Sphere
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
City and County Boundary
Drainage Sub Basins
<all other values>
Black River
Boren Creek
Cabbage Creek
Cedar Grove
Cedar Main Urban
China Creek
Country Creek
Duamish
East Fork May Creek
Garrison Creek
Ginger Creek
Greenes Creek
Gypsy
Honey Creek
Jenkins Creek Main
Lake Kathleen
Lake Washington - East
Lake Washington - West
Johns Creek
Lake Washington South
Little Soos Creek
Long Marsh Creek
Lower May Creek
Project Site
Figure 6B - Drainage Basin Map
FIGURE 6C
MODIFIED C - VALUE CALCULATION
Surface Type C Factor
Catchbasin
Number Surface Type Area (ft) Area (ac)
Total Area
(ac)
Weighted C
Value Impervious 0.9
Impervious 2306 0.0529 Pervious 0.25
Pervious 0.0000
Impervious 1363 0.0313
Pervious 0.0000
Impervious 1664 0.0382
Pervious 0.0000
Impervious 4252 0.0976
Pervious 0.0000
Impervious 4249 0.0975 SURFACE TYPE SF AC
Pervious 0.0000 IMPERVIOUS 28125 0.646
Impervious 3161 0.0726 PERVIOUS 327 0.008
Pervious 0.0000 IMPERVIOUS 2682 0.062
Impervious 3131 0.0719 PERVIOUS 0 0.000
Pervious 0.0000 IMPERVIOUS 30807 0.707
Impervious 2574 0.0591 PERVIOUS 327 0.008
Pervious 0.0000
Impervious 3686 0.0846
Pervious 105 0.0024
Impervious 1739 0.0399
Pervious 222 0.0051
Impervious 2682 0.0616
Pervious 0.0000
TOTAL
NEW/REPLACED
WQ BASIN #2
WQ BASIN #1*
WATER QUALITY BASIN SUMMARY
A10 0.0726 0.90
C2 0.0616 0.90
A14 0.0450 0.83
A13 0.0870 0.88
A11 0.0719 0.90
A12 0.0591 0.90
A9 0.0975 0.90
A6 0.0313 0.90
A7 0.0382 0.90
A5 0.900.0529
A8 0.0976 0.90
Southport PSE Shuffleton
C180194-03 3/30/2021
FIGURE 6D
PROPOSED ADDITIONAL IMPERVIOUS AREA MAP
1" : 60'
PROPOSED SITE CONDITIONS
Description Quantity Unit
EXISTING IMPERVIOUS TO PSE BYPASS 0.44 ac
NEW IMPERVIOUS TO PSE BYPASS 0.28 ac
Southport PSE Shuffleton
C180194-03 3/30/2021
FIGURE 6E
PROPOSED STORM CONVEYANCE PROFILE
SOUTHPORT PSE CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON SITE
1/25/2021
FIGURE 7
PROPOSED SITE CONDITIONS
1" : 60'
PROPOSED SITE CONDITIONS
Description Quantity Unit
IMPERVIOUS 0.72 ac
PERVIOUS 0.35 ac
Southport PSE Shuffleton
C180194-03 3/29/2021
PARCEL A0 20 40 80
SCALE 1"=40'
Added basin area to be
added to existing PSE
drainage system
(12,640 SF) (0.29 AC)
Legend
Existing storm drainage
system already
accounted for in
existing PSE system
(9,900 SF) (0.22 AC)
Figure 7B - Additional Impervious Area Map
C180194-03 August 2019
Southport Park Avenue Extension
Upstream
segment of public
portion of Park
Avenue extension,
draining on to
project site
Portion of proposed
roadway stormwater
has already been
evaluated with
previous Southport
Office project, Permit
#SW18001113
LakeDesire
ShadyLake (MudLake)
PantherLake LakeYoungs
LakeWashington
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RReennttoonnMMaapplleeVVaalllleeyyRRdd
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110088tthhAAvveeSSEESSWWSSuunnsseettBBllvvdd RRaaii
nnii
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AAvveeNNNE 3rd StNE 3rd St
SW 43rd StSW 43rd St SSEE CCaarrrrRR dd
NE 4th StNE 4th St
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SR 515SR 515PPaarrkkAAvveeNNOOaakkeessddaalleeAAvveeSSWWSSuunnsseettBBllvvddNNEE
DDuuvvaallllAAvveeNNEEI-405 FWYI-405 FWY II--440055FFWWYYSR 167SR 167114400tthh
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115566tthhAAvveeSSEEUUnniioonnAAvveeNNEE111166tthhAAvveeSSEESW 7th StSW 7th St
N 8th StN 8th St
PP uuggeettDDrrSSEE
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SS 221122tthh SStt
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CCrreeeekkPPkkwwyySSEESW 41st StSW 41st St
114400tthhAAvveeSSEE112288tthhAAvveeSSEE6688tthhAAvveeSSSSEE 116688tthh SStt
NE 12th StNE 12th St
BBee
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SS
FFoorreessttDDrr SSEE
SSEE 116644tthh SStt 114488tthhAAvveeSSEESSEEMMaayy VVaalllleeyyRRdd
SS EE JJoonneess RRdd
SSEE 22 00 44 tthh WW aayySW 34th StSW 34th St
SE 144th StSE 144th St
114488tthhAAvveeSSEE115544tthhPPllSSEELL
aa
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vvddNNEEddmmoonnddssAAvveeNNEEAAbbeerrddeeeennAAvveeNNEEEEMM eerrcceerrWWaayyWWeessttVVaalllleeyyHHwwyyEast Valley RdEast Valley Rd,§-405
,§-405
,§-405
µ0 1 2Miles
Flow Control Application Map
Reference 15-A
Date: 01/09/2014
Flow Control Standards
Peak Rate Flow Control Standard (Existing Site Conditions)
Flow Control Duration Standard (Existing Site Conditions)
Flow Control Duration Standard (Forested Conditions)
Flood Problem Flow
Unincorporated King County Flow Control Standards
Renton City Limits
Potential Annexation Area
Figure 8 - Flow Control Application Map
Project Site
Figure 9 - FEMA Flood Insurance Rate Map (FIRM)
Southport Park
Avenue Extension
Site (Approximate)
k
k
k
k
k
k
k
k
k
k k
k
k
k
k
k
k
k
k
k
k
k
k
k
k
k
k
kk
k
k
k
k
k
k
k
k
k
k
k
k
k
k
k
k
k
k
k HoquiamAveNEE Valley Hwy84thAveSNEParkDr
SW 7th St
SE 128th St
SE 192nd StLind Ave SWMainAveSS 132nd St
Factory
PlN
Tal
bot
Rd
SN 3rd St
RainierAveS
164thAveSETukwilaPkwy SPugetDr
NE 4th St
S 3rd St
S 1 2 9 th S t68thAveSSWSunsetBlvd
SW 16th St
116thAveSEN 4th St
In
t
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S WilliamsAveNBronsonWa y N
NE7thSt
124thAveSES 7th St SERento n IssaquahRd
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CoalCre
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Ta
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NW NESunsetBlvdWellsAveNUnionAveNENE 3rd St
Hardie
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140thAveSES G ra d y W ayS 2 1 s tSt
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AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrRd
SE 168thSt
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141s
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AveSERainierAveS 156thAveSES E 183rdStBe
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S W G ra dyW a y
SE J o n es RdSunsetBlvdN
Puget Dr SESE 204th
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SW 34th StMo
n
sterRdSW SE 142nd Pl
WestValleyHwySSEMayValleyRd
SunsetBlvdNS Carr RdHouserWayNNewcastleGolfClubRd
S 133rd St
WilliamsAveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRaini
er
AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAveSWestVall
eyHwyWestValleyHwyParkAveN108thAveSE6
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S WM ercerWayWMercer
W
ay LakemontBl
vdSE132ndAve SELakeWashingtonBlvdNE140thWaySE
East Valley Rd68thAveS³City of RentonSensitive Areas
0 0.5 10.25
Miles
Information Technology - GISmapsupport@rentonwa.govPrinted on: 11/12/2014
Data Sources: City of Renton, King County
This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only.
Renton City Limits
k Education
Fire Station
K Valley Medical Center
Aquifer Protection
Zone 1
Zone 1 Modified
Zone 2
Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN
Figure 10 - Aquifer Protection Map
Project Site
9,028 752
Figure 11 - Offsite Analysis Map
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
None
5/20/2019
Legend
5120256
THIS MAP IS NOT TO BE USED FOR NAVIGATION
Feet
Notes
512
WGS_1984_Web_Mercator_Auxiliary_Sphere
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
City and County Boundary
Parcels
Water Gravity Pipes
Water Mains
Mains - Other System
Water Service Areas
Lift Stations
Pressurized Mains
Renton
Private
Gravity Mains
Renton
Private
Wastewater Service Areas
KC Pressurized Mains
KC Gravity Mains
Pump Stations
Discharge Points
Stormwater Mains
Culverts
Open Drains
Facility Outlines
Private Pump Stations
Private Discharge Points
Private Pipes
Private Culverts
EXISTING PSE
DRAINAGE
SYSTEM ROUTE
Project Site
CONNECTION
TO EXISTING
PSE DRAINAGE
SYSTEM
Figure 11 -Offsite Analysis Map
John's
Creek
Appendix B – Engineering Calculations
SOUTHPORT PARK AVENUE EXTNSION CONVEYANCE ANALYSIS
STORMFILTER SIZING (WWHM)
Project Description
FINAL SSA DRAINAGE MODEL - PERMIT SET.SPF
Project Options
CFS
Elevation
Rational
SCS TR-55
Hydrodynamic
YES
NO
Analysis Options
Mar 29, 2021 00:00:00
Mar 30, 2021 00:00:00
Mar 29, 2021 00:00:00
0 days
0 01:00:00 days hh:mm:ss
0 00:05:00 days hh:mm:ss
0 00:05:00 days hh:mm:ss
30 seconds
Number of Elements
Qty
0
11
19
18
1
0
0
0
18
0
18
0
0
0
0
0
0
Rainfall Details
25 year(s)
Outlets ..........................................................................
Pollutants ..............................................................................
Land Uses ............................................................................
Return Period........................................................................
Links......................................................................................
Channels ......................................................................
Pipes ............................................................................
Pumps ..........................................................................
Orifices .........................................................................
Weirs ............................................................................
Nodes....................................................................................
Junctions ......................................................................
Outfalls .........................................................................
Flow Diversions ...........................................................
Inlets ............................................................................
Storage Nodes .............................................................
Runoff (Dry Weather) Time Step ..........................................
Runoff (Wet Weather) Time Step ........................................
Reporting Time Step ............................................................
Routing Time Step ................................................................
Rain Gages ...........................................................................
Subbasins..............................................................................
Enable Overflow Ponding at Nodes ......................................
Skip Steady State Analysis Time Periods ............................
Start Analysis On ..................................................................
End Analysis On ...................................................................
Start Reporting On ................................................................
Antecedent Dry Days ............................................................
File Name .............................................................................
Flow Units .............................................................................
Elevation Type ......................................................................
Hydrology Method .................................................................
Time of Concentration (TOC) Method ..................................
Link Routing Method .............................................................
3/30/2021 Page 1
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin Summary
SN Subbasin Area Weighted Total Total Total Peak Time of
ID Runoff Rainfall Runoff Runoff Runoff Concentration
Coefficient Volume
(ac)(in)(in)(ac-in)(cfs)(days hh:mm:ss)
1 Sub-CB#A10 0.07 0.9000 0.29 0.26 0.02 0.18 0 00:06:18
2 Sub-CB#A11 0.07 0.9000 0.29 0.26 0.02 0.18 0 00:06:18
3 Sub-CB#A12 0.06 0.9000 0.29 0.26 0.02 0.15 0 00:06:18
4 Sub-CB#A13 0.09 0.8800 0.29 0.25 0.02 0.21 0 00:06:18
5 Sub-CB#A14 0.05 0.8300 0.29 0.24 0.01 0.10 0 00:06:18
6 Sub-CB#A5 0.05 0.9000 0.29 0.26 0.01 0.13 0 00:06:18
7 Sub-CB#A6 0.03 0.9000 0.29 0.26 0.01 0.08 0 00:06:18
8 Sub-CB#A7 0.04 0.9000 0.29 0.26 0.01 0.09 0 00:06:18
9 Sub-CB#A8 0.10 0.9000 0.29 0.26 0.03 0.24 0 00:06:18
10 Sub-CB#A9 0.10 0.9000 0.29 0.26 0.03 0.24 0 00:06:18
11 Sub-CB#C2 0.06 0.9000 0.29 0.26 0.02 0.15 0 00:06:18
3/30/2021 Page 2
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max)Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft)(ft)(ft)(ft)(ft²)(cfs)(ft)(ft)(ft)(days hh:mm)(ac-in)(min)
1 # 78 Junction -0.50 32.44 -0.50 32.44 0.00 0.08 -0.21 0.00 32.65 0 00:00 0.00 0.00
2 CB# B0 EX Junction 18.00 22.10 18.00 22.10 100.00 4.59 19.72 0.00 2.38 0 00:00 0.00 0.00
3 CB#A1 Junction 17.43 21.63 17.43 21.63 100.00 6.74 19.16 0.00 2.47 0 00:00 0.00 0.00
4 CB#A10 Junction 21.48 24.27 21.48 24.27 100.00 0.62 21.81 0.00 2.45 0 00:00 0.00 0.00
5 CB#A11 Junction 22.00 26.00 22.00 26.00 100.00 0.50 22.27 0.00 3.73 0 00:00 0.00 0.00
6 CB#A12 Junction 24.52 28.52 24.52 28.52 100.00 0.35 24.67 0.00 3.85 0 00:00 0.00 0.00
7 CB#A13 Junction 26.40 30.40 26.40 30.40 100.00 0.23 26.52 0.00 3.88 0 00:00 0.00 0.00
8 CB#A14 Junction 27.65 31.30 27.65 31.30 100.00 0.10 27.69 0.00 3.62 0 00:00 0.00 0.00
9 CB#A2 Junction 17.47 21.63 17.47 21.63 100.00 4.00 19.17 0.00 2.46 0 00:00 0.00 0.00
10 CB#A3 Junction 17.58 21.80 17.58 21.80 100.00 3.80 19.17 0.00 2.63 0 00:00 0.00 0.00
11 CB#A4 Junction 17.70 22.53 17.70 22.53 100.00 2.93 19.18 0.00 3.35 0 00:00 0.00 0.00
12 CB#A5 Junction 18.45 21.50 18.45 21.50 100.00 0.94 19.24 0.00 2.26 0 00:00 0.00 0.00
13 CB#A6 Junction 19.80 22.15 19.80 22.15 100.00 0.90 20.18 0.00 1.97 0 00:00 0.00 0.00
14 CB#A7 Junction 20.14 22.31 20.14 22.29 100.00 0.89 20.53 0.00 1.78 0 00:00 0.00 0.00
15 CB#A8 Junction 20.56 22.48 20.56 22.48 100.00 0.86 20.92 0.00 1.56 0 00:00 0.00 0.00
16 CB#A9 Junction 21.02 23.20 21.02 23.20 100.00 0.75 21.40 0.00 1.80 0 00:00 0.00 0.00
17 CB#C1 Junction 17.95 22.00 17.95 22.00 100.00 6.72 19.58 0.00 2.42 0 00:00 0.00 0.00
18 CB#C2 Junction 18.13 21.97 18.13 21.97 100.00 1.27 19.58 0.00 2.39 0 00:00 0.00 0.00
19 Out-1Pipe - (74)Outfall 16.88 5.45 18.58
3/30/2021 Page 3
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Link Summary
SN Element Element From To (Outlet)Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Flow/Peak Flow Peak Flow Peak Flow Total Time Reported
ID Type (Inlet)Node Invert Invert Slope Height Roughness Flow Capacity Design Flow Velocity Depth Depth/Surcharged Condition
Node Elevation Elevation Ratio Total Depth
Ratio
(ft)(ft)(ft)(%)(in)(cfs)(cfs)(ft/sec)(ft)(min)
1 Pipe - (11)Pipe CB#A11 CB#A10 73.85 22.00 21.48 0.7000 12.000 0.0120 0.47 3.23 0.15 2.44 0.30 0.30 0.00 Calculated
2 Pipe - (30)Pipe CB#A7 CB#A6 37.85 20.14 19.80 0.9100 12.000 0.0120 0.87 3.69 0.24 3.15 0.38 0.38 0.00 Calculated
3 Pipe - (32)Pipe CB# B0 EX CB#C1 19.54 18.00 17.95 0.2600 18.000 0.0120 6.72 5.76 1.17 6.87 1.50 1.00 11.00 SURCHARGED
4 Pipe - (33)Pipe CB#C1 CB#A1 193.36 17.95 17.43 0.2700 18.000 0.0120 4.65 5.90 0.79 2.97 1.50 1.00 11.00 SURCHARGED
5 Pipe - (39)Pipe CB#A8 CB#A7 41.61 20.56 20.14 1.0000 12.000 0.0120 0.84 3.86 0.22 3.16 0.37 0.37 0.00 Calculated
6 Pipe - (40)Pipe # 78 CB#A14 40.74 -0.50 27.65 -69.1000 12.000 0.0120 0.08 32.08 0.00 8.18 0.14 0.14 0.00 Calculated
7 Pipe - (41)Pipe CB#A14 CB#A13 40.29 27.65 26.40 3.1000 12.000 0.0120 0.02 6.80 0.00 0.61 0.08 0.08 0.00 Calculated
8 Pipe - (42)Pipe CB#A13 CB#A12 57.20 26.40 24.52 3.2900 12.000 0.0120 0.21 7.00 0.03 3.38 0.13 0.13 0.00 Calculated
9 Pipe - (43)Pipe CB#A12 CB#A11 76.96 24.52 22.00 3.2700 12.000 0.0120 0.34 6.98 0.05 2.89 0.21 0.21 0.00 Calculated
10 Pipe - (5)Pipe CB#A10 CB#A9 91.83 21.48 21.02 0.5000 12.000 0.0120 0.59 2.73 0.22 2.38 0.35 0.35 0.00 Calculated
11 Pipe - (6)Pipe CB#A9 CB#A8 92.58 21.02 20.56 0.5000 12.000 0.0120 0.72 2.73 0.26 2.72 0.37 0.37 0.00 Calculated
12 Pipe - (67)Pipe CB#A6 CB#A5 29.84 19.80 19.50 1.0000 12.000 0.0120 0.89 3.86 0.23 3.55 0.36 0.36 0.00 Calculated
13 Pipe - (7)Pipe CB#C2 CB#C1 36.33 18.13 17.95 0.5000 12.000 0.0120 1.23 2.74 0.45 2.43 1.00 1.00 1436.00 SURCHARGED
14 Pipe - (70)Pipe CB#A3 CB#A2 39.45 17.58 17.47 0.3000 18.000 0.0120 3.80 6.22 0.61 3.43 1.50 1.00 7.00 SURCHARGED
15 Pipe - (71)Pipe CB#A2 CB#A1 11.69 17.47 17.43 0.3000 18.000 0.0120 4.00 6.23 0.64 4.39 1.50 1.00 1433.00 SURCHARGED
16 Pipe - (73)Pipe CB#A5 CB#A4 106.30 18.45 17.70 0.7100 12.000 0.0120 0.86 3.24 0.26 1.20 0.90 0.90 0.00 Calculated
17 Pipe - (74)Pipe CB#A1 Out-1Pipe - (74)189.88 17.43 16.88 0.2900 18.000 0.0120 5.45 6.12 0.89 3.08 1.50 1.00 1433.00 SURCHARGED
18 Pipe - (76)Pipe CB#A4 CB#A3 39.43 17.70 17.58 0.3000 18.000 0.0120 2.91 6.23 0.47 3.29 1.49 0.99 0.00 Calculated
3/30/2021 Page 4
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin Hydrology
Subbasin : Sub-CB#A10
Input Data
Area (ac) ........................................................................0.07
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.07 -0.90
Composite Area & Weighted Runoff Coeff.0.07 0.90
Time of Concentration
TOC Method : SCS TR-55
Sheet Flow Equation :
Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4))
Where :
Tc = Time of Concentration (hr)
n = Manning's roughness
Lf = Flow Length (ft)
P = 2 yr, 24 hr Rainfall (inches)
Sf = Slope (ft/ft)
Shallow Concentrated Flow Equation :
V = 16.1345 * (Sf^0.5) (unpaved surface)
V = 20.3282 * (Sf^0.5) (paved surface)
V = 15.0 * (Sf^0.5) (grassed waterway surface)
V = 10.0 * (Sf^0.5) (nearly bare & untilled surface)
V = 9.0 * (Sf^0.5) (cultivated straight rows surface)
V = 7.0 * (Sf^0.5) (short grass pasture surface)
V = 5.0 * (Sf^0.5) (woodland surface)
V = 2.5 * (Sf^0.5) (forest w/heavy litter surface)
Tc = (Lf / V) / (3600 sec/hr)
Where:
Tc = Time of Concentration (hr)
Lf = Flow Length (ft)
V = Velocity (ft/sec)
Sf = Slope (ft/ft)
Channel Flow Equation :
V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n
R = Aq / Wp
Tc = (Lf / V) / (3600 sec/hr)
Where :
Tc = Time of Concentration (hr)
Lf = Flow Length (ft)
R = Hydraulic Radius (ft)
Aq = Flow Area (ft²)
Wp = Wetted Perimeter (ft)
V = Velocity (ft/sec)
Sf = Slope (ft/ft)
n = Manning's roughness
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.18
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 5
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A10
3/30/2021 Page 6
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A11
Input Data
Area (ac) ........................................................................0.07
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.07 -0.90
Composite Area & Weighted Runoff Coeff.0.07 0.90
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.18
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 7
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A11
3/30/2021 Page 8
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A12
Input Data
Area (ac) ........................................................................0.06
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.06 -0.90
Composite Area & Weighted Runoff Coeff.0.06 0.90
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.15
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 9
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A12
3/30/2021 Page 10
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A13
Input Data
Area (ac) ........................................................................0.09
Weighted Runoff Coefficient ..........................................0.8800
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.09 -0.88
Composite Area & Weighted Runoff Coeff.0.09 0.88
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.25
Peak Runoff (cfs) ...........................................................0.21
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.8800
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 11
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A13
3/30/2021 Page 12
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A14
Input Data
Area (ac) ........................................................................0.05
Weighted Runoff Coefficient ..........................................0.8300
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.05 -0.83
Composite Area & Weighted Runoff Coeff.0.05 0.83
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.24
Peak Runoff (cfs) ...........................................................0.10
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.8300
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 13
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A14
3/30/2021 Page 14
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A5
Input Data
Area (ac) ........................................................................0.05
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.05 -0.90
Composite Area & Weighted Runoff Coeff.0.05 0.90
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.13
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 15
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A5
3/30/2021 Page 16
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A6
Input Data
Area (ac) ........................................................................0.03
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.03 -0.90
Composite Area & Weighted Runoff Coeff.0.03 0.90
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.08
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 17
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A6
3/30/2021 Page 18
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A7
Input Data
Area (ac) ........................................................................0.04
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.04 -0.90
Composite Area & Weighted Runoff Coeff.0.04 0.90
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.09
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 19
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A7
3/30/2021 Page 20
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A8
Input Data
Area (ac) ........................................................................0.10
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.10 -0.90
Composite Area & Weighted Runoff Coeff.0.10 0.90
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.24
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 21
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A8
3/30/2021 Page 22
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A9
Input Data
Area (ac) ........................................................................0.10
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.10 -0.90
Composite Area & Weighted Runoff Coeff.0.10 0.90
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.24
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 23
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#A9
3/30/2021 Page 24
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#C2
Input Data
Area (ac) ........................................................................0.06
Weighted Runoff Coefficient ..........................................0.9000
Runoff Coefficient
Area Soil Runoff
Soil/Surface Description (acres)Group Coeff.
-0.06 -0.90
Composite Area & Weighted Runoff Coeff.0.06 0.90
Time of Concentration
User-Defined TOC override (minutes): 6.3
Subbasin Runoff Results
Total Rainfall (in) ............................................................0.29
Total Runoff (in) .............................................................0.26
Peak Runoff (cfs) ...........................................................0.15
Rainfall Intensity .............................................................2.733
Weighted Runoff Coefficient ..........................................0.9000
Time of Concentration (days hh:mm:ss) ........................0 00:06:18
3/30/2021 Page 25
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Subbasin : Sub-CB#C2
3/30/2021 Page 26
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Junction Input
SN Element Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum
ID Elevation (Max)(Max)Water Water Elevation Depth Area Pipe
Elevation Offset Elevation Depth Cover
(ft)(ft)(ft)(ft)(ft)(ft)(ft)(ft²)(in)
1 # 78 -0.50 32.44 32.94 -0.50 0.00 32.44 0.00 0.00 383.28
2 CB# B0 EX 18.00 22.10 4.10 18.00 0.00 22.10 0.00 100.00 31.20
3 CB#A1 17.43 21.63 4.20 17.43 0.00 21.63 0.00 100.00 32.40
4 CB#A10 21.48 24.27 2.78 21.48 0.00 24.27 0.00 100.00 21.40
5 CB#A11 22.00 26.00 4.00 22.00 0.00 26.00 0.00 100.00 36.00
6 CB#A12 24.52 28.52 4.00 24.52 0.00 28.52 0.00 100.00 36.02
7 CB#A13 26.40 30.40 4.00 26.40 0.00 30.40 0.00 100.00 35.98
8 CB#A14 27.65 31.30 3.65 27.65 0.00 31.30 0.00 100.00 31.85
9 CB#A2 17.47 21.63 4.17 17.47 0.00 21.63 0.00 100.00 31.98
10 CB#A3 17.58 21.80 4.22 17.58 0.00 21.80 0.00 100.00 32.60
11 CB#A4 17.70 22.53 4.83 17.70 0.00 22.53 0.00 100.00 39.91
12 CB#A5 18.45 21.50 3.05 18.45 0.00 21.50 0.00 100.00 12.00
13 CB#A6 19.80 22.15 2.35 19.80 0.00 22.15 0.00 100.00 16.24
14 CB#A7 20.14 22.31 2.17 20.14 0.00 22.29 -0.02 100.00 13.99
15 CB#A8 20.56 22.48 1.92 20.56 0.00 22.48 0.00 100.00 11.07
16 CB#A9 21.02 23.20 2.17 21.02 0.00 23.20 0.00 100.00 14.08
17 CB#C1 17.95 22.00 4.05 17.95 0.00 22.00 0.00 100.00 30.60
18 CB#C2 18.13 21.97 3.84 18.13 0.00 21.97 0.00 100.00 34.05
3/30/2021 Page 27
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Junction Results
SN Element Peak Peak Max HGL Max HGL Max Min Average HGL Average HGL Time of Time of Total Total Time
ID Inflow Lateral Elevation Depth Surcharge Freeboard Elevation Depth Max HGL Peak Flooded Flooded
Inflow Attained Attained Depth Attained Attained Attained Occurrence Flooding Volume
Attained Occurrence
(cfs)(cfs)(ft)(ft)(ft)(ft)(ft)(ft)(days hh:mm)(days hh:mm)(ac-in)(min)
1 # 78 0.08 0.00 -0.21 0.29 0.00 32.65 -0.22 0.28 0 00:40 0 00:00 0.00 0.00
2 CB# B0 EX 4.59 4.59 19.72 1.72 0.00 2.38 19.51 1.51 0 00:11 0 00:00 0.00 0.00
3 CB#A1 6.74 0.00 19.16 1.73 0.00 2.47 18.99 1.56 0 00:12 0 00:00 0.00 0.00
4 CB#A10 0.62 0.18 21.81 0.33 0.00 2.45 21.49 0.01 0 00:08 0 00:00 0.00 0.00
5 CB#A11 0.50 0.18 22.27 0.27 0.00 3.73 22.00 0.00 0 00:07 0 00:00 0.00 0.00
6 CB#A12 0.35 0.15 24.67 0.15 0.00 3.85 24.52 0.00 0 00:07 0 00:00 0.00 0.00
7 CB#A13 0.23 0.21 26.52 0.12 0.00 3.88 26.40 0.00 0 00:06 0 00:00 0.00 0.00
8 CB#A14 0.10 0.10 27.69 0.04 0.00 3.62 27.65 0.00 0 00:06 0 00:00 0.00 0.00
9 CB#A2 4.00 0.00 19.17 1.70 0.00 2.46 18.99 1.52 0 00:12 0 00:00 0.00 0.00
10 CB#A3 3.80 0.00 19.17 1.59 0.00 2.63 18.99 1.41 0 00:12 0 00:00 0.00 0.00
11 CB#A4 2.93 0.00 19.18 1.48 0.00 3.35 18.99 1.29 0 00:12 0 00:00 0.00 0.00
12 CB#A5 0.94 0.13 19.24 0.79 0.00 2.26 18.99 0.54 0 00:11 0 00:00 0.00 0.00
13 CB#A6 0.90 0.08 20.18 0.38 0.00 1.97 19.81 0.01 0 00:10 0 00:00 0.00 0.00
14 CB#A7 0.89 0.09 20.53 0.39 0.00 1.78 20.15 0.01 0 00:10 0 00:00 0.00 0.00
15 CB#A8 0.86 0.24 20.92 0.36 0.00 1.56 20.57 0.01 0 00:09 0 00:00 0.00 0.00
16 CB#A9 0.75 0.24 21.40 0.38 0.00 1.80 21.03 0.01 0 00:09 0 00:00 0.00 0.00
17 CB#C1 6.72 0.00 19.58 1.63 0.00 2.42 19.38 1.43 0 00:11 0 00:00 0.00 0.00
18 CB#C2 1.27 0.15 19.58 1.45 0.00 2.39 19.38 1.25 0 00:11 0 00:00 0.00 0.00
3/30/2021 Page 28
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap No. of
ID Invert Invert Invert Invert Drop Slope Shape Diameter or Width Roughness Losses Losses Losses Flow Gate Barrels
Elevation Offset Elevation Offset Height
(ft)(ft)(ft)(ft)(ft)(ft)(%)(in)(in)(cfs)
1 Pipe - (11)73.85 22.00 0.00 21.48 0.00 0.52 0.7000 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
2 Pipe - (30)37.85 20.14 0.00 19.80 0.00 0.35 0.9100 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
3 Pipe - (32)19.54 18.00 0.00 17.95 0.00 0.05 0.2600 CIRCULAR 18.000 18.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
4 Pipe - (33)193.36 17.95 0.00 17.43 0.00 0.52 0.2700 CIRCULAR 18.000 18.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
5 Pipe - (39)41.61 20.56 0.00 20.14 0.00 0.42 1.0000 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
6 Pipe - (40)40.74 -0.50 0.00 27.65 0.00 -28.15 -69.1000 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
7 Pipe - (41)40.29 27.65 0.00 26.40 0.00 1.25 3.1000 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
8 Pipe - (42)57.20 26.40 0.00 24.52 0.00 1.88 3.2900 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
9 Pipe - (43)76.96 24.52 0.00 22.00 0.00 2.52 3.2700 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
10 Pipe - (5)91.83 21.48 0.00 21.02 0.00 0.46 0.5000 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
11 Pipe - (6)92.58 21.02 0.00 20.56 0.00 0.46 0.5000 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
12 Pipe - (67)29.84 19.80 0.00 19.50 1.05 0.30 1.0000 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
13 Pipe - (7)36.33 18.13 0.00 17.95 0.00 0.18 0.5000 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
14 Pipe - (70)39.45 17.58 0.00 17.47 0.00 0.12 0.3000 CIRCULAR 18.000 18.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
15 Pipe - (71)11.69 17.47 0.00 17.43 0.00 0.04 0.3000 CIRCULAR 18.000 18.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
16 Pipe - (73)106.30 18.45 0.00 17.70 0.00 0.75 0.7100 CIRCULAR 12.000 12.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
17 Pipe - (74)189.88 17.43 0.00 16.88 0.00 0.55 0.2900 CIRCULAR 18.000 18.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
18 Pipe - (76)39.43 17.70 0.00 17.58 0.00 0.12 0.3000 CIRCULAR 18.000 18.000 0.0120 0.5000 0.5000 0.0000 0.00 No 1
3/30/2021 Page 29
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
Pipe Results
SN Element Peak Time of Design Flow Peak Flow/Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs)(days hh:mm)(cfs)(ft/sec)(min)(ft)(min)
1 Pipe - (11)0.47 0 00:07 3.23 0.15 2.44 0.50 0.30 0.30 0.00 Calculated
2 Pipe - (30)0.87 0 00:10 3.69 0.24 3.15 0.20 0.38 0.38 0.00 Calculated
3 Pipe - (32)6.72 0 00:00 5.76 1.17 6.87 0.05 1.50 1.00 11.00 SURCHARGED
4 Pipe - (33)4.65 0 00:10 5.90 0.79 2.97 1.09 1.50 1.00 11.00 SURCHARGED
5 Pipe - (39)0.84 0 00:09 3.86 0.22 3.16 0.22 0.37 0.37 0.00 Calculated
6 Pipe - (40)0.08 0 00:06 32.08 0.00 8.18 0.08 0.14 0.14 0.00 Calculated
7 Pipe - (41)0.02 0 00:06 6.80 0.00 0.61 1.10 0.08 0.08 0.00 Calculated
8 Pipe - (42)0.21 0 00:06 7.00 0.03 3.38 0.28 0.13 0.13 0.00 Calculated
9 Pipe - (43)0.34 0 00:07 6.98 0.05 2.89 0.44 0.21 0.21 0.00 Calculated
10 Pipe - (5)0.59 0 00:08 2.73 0.22 2.38 0.64 0.35 0.35 0.00 Calculated
11 Pipe - (6)0.72 0 00:09 2.73 0.26 2.72 0.57 0.37 0.37 0.00 Calculated
12 Pipe - (67)0.89 0 00:10 3.86 0.23 3.55 0.14 0.36 0.36 0.00 Calculated
13 Pipe - (7)1.23 0 00:01 2.74 0.45 2.43 0.25 1.00 1.00 1436.00 SURCHARGED
14 Pipe - (70)3.80 0 00:02 6.22 0.61 3.43 0.19 1.50 1.00 7.00 SURCHARGED
15 Pipe - (71)4.00 0 00:01 6.23 0.64 4.39 0.04 1.50 1.00 1433.00 SURCHARGED
16 Pipe - (73)0.86 0 00:11 3.24 0.26 1.20 1.48 0.90 0.90 0.00 Calculated
17 Pipe - (74)5.45 0 00:12 6.12 0.89 3.08 1.03 1.50 1.00 1433.00 SURCHARGED
18 Pipe - (76)2.91 0 00:03 6.23 0.47 3.29 0.20 1.49 0.99 0.00 Calculated
3/30/2021 Page 30
CONVEYANCE ANALYSIS
SOUTHPORT PSE SHUFFLETON
WWHM2012
PROJECT REPORT
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:12:52 PM Page 2
General Model Information
Project Name:2021-03-29 WWHM WQ FACILITY
Site Name:
Site Address:
City:
Report Date:3/30/2021
Gage:Seatac
Data Start:1948/10/01
Data End:2009/09/30
Timestep:15 Minute
Precip Scale:1.000
Version Date:2019/09/13
Version:4.2.17
POC Thresholds
Low Flow Threshold for POC1:50 Percent of the 2 Year
High Flow Threshold for POC1:50 Year
Low Flow Threshold for POC2:50 Percent of the 2 Year
High Flow Threshold for POC2:50 Year
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:12:52 PM Page 3
Landuse Basin Data
Predeveloped Land Use
WQ BASIN #1
Bypass:No
GroundWater:No
Pervious Land Use acre
C, Lawn, Flat 0.008
Pervious Total 0.008
Impervious Land Use acre
ROADS FLAT 0.646
Impervious Total 0.646
Basin Total 0.654
Element Flows To:
Surface Interflow Groundwater
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:12:52 PM Page 4
WQ BASIN #2
Bypass:No
GroundWater:No
Pervious Land Use acre
Pervious Total 0
Impervious Land Use acre
ROADS FLAT 0.062
Impervious Total 0.062
Basin Total 0.062
Element Flows To:
Surface Interflow Groundwater
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:12:52 PM Page 5
Mitigated Land Use
WQ BASIN #1
Bypass:No
GroundWater:No
Pervious Land Use acre
C, Lawn, Mod 0.008
Pervious Total 0.008
Impervious Land Use acre
ROADS FLAT 0.646
Impervious Total 0.646
Basin Total 0.654
Element Flows To:
Surface Interflow Groundwater
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:12:52 PM Page 6
WQ BASIN #2
Bypass:No
GroundWater:No
Pervious Land Use acre
Pervious Total 0
Impervious Land Use acre
ROADS FLAT 0.062
Impervious Total 0.062
Basin Total 0.062
Element Flows To:
Surface Interflow Groundwater
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:12:52 PM Page 7
Routing Elements
Predeveloped Routing
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:12:52 PM Page 8
Mitigated Routing
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:12:52 PM Page 9
Analysis Results
POC 1
+ Predeveloped x Mitigated
Predeveloped Landuse Totals for POC #1
Total Pervious Area:0.008
Total Impervious Area:0.646
Mitigated Landuse Totals for POC #1
Total Pervious Area:0.008
Total Impervious Area:0.646
Flow Frequency Method:Log Pearson Type III 17B
Flow Frequency Return Periods for Predeveloped. POC #1
Return Period Flow(cfs)
2 year 0.246814
5 year 0.311921
10 year 0.356174
25 year 0.413596
50 year 0.457558
100 year 0.502597
Flow Frequency Return Periods for Mitigated. POC #1
Return Period Flow(cfs)
2 year 0.246911
5 year 0.312079
10 year 0.356378
25 year 0.413863
50 year 0.457875
100 year 0.502968
Annual Peaks
Annual Peaks for Predeveloped and Mitigated. POC #1
Year Predeveloped Mitigated
1949 0.320 0.320
1950 0.345 0.345
1951 0.200 0.200
1952 0.177 0.177
1953 0.192 0.192
1954 0.201 0.201
1955 0.227 0.228
1956 0.224 0.224
1957 0.254 0.254
1958 0.205 0.205
100 - YEAR PEAK
FLOW RATE FOR 4
- CARTRIDGE
CONTECH
STORMFILTER
FACILITY
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:13:23 PM Page 10
1959 0.209 0.209
1960 0.206 0.206
1961 0.217 0.217
1962 0.189 0.189
1963 0.210 0.210
1964 0.206 0.206
1965 0.262 0.262
1966 0.175 0.175
1967 0.301 0.302
1968 0.343 0.343
1969 0.239 0.239
1970 0.230 0.230
1971 0.274 0.274
1972 0.284 0.284
1973 0.171 0.171
1974 0.250 0.251
1975 0.288 0.288
1976 0.194 0.194
1977 0.209 0.209
1978 0.256 0.256
1979 0.351 0.351
1980 0.316 0.316
1981 0.258 0.258
1982 0.364 0.364
1983 0.296 0.296
1984 0.187 0.187
1985 0.257 0.257
1986 0.223 0.223
1987 0.344 0.344
1988 0.208 0.208
1989 0.261 0.261
1990 0.442 0.442
1991 0.353 0.353
1992 0.185 0.185
1993 0.160 0.160
1994 0.174 0.174
1995 0.229 0.229
1996 0.244 0.244
1997 0.237 0.237
1998 0.239 0.239
1999 0.491 0.491
2000 0.244 0.244
2001 0.268 0.268
2002 0.313 0.313
2003 0.243 0.244
2004 0.459 0.459
2005 0.210 0.210
2006 0.185 0.186
2007 0.429 0.429
2008 0.346 0.347
2009 0.318 0.318
Ranked Annual Peaks
Ranked Annual Peaks for Predeveloped and Mitigated. POC #1
Rank Predeveloped Mitigated
1 0.4907 0.4911
2 0.4590 0.4593
3 0.4419 0.4422
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:13:23 PM Page 11
4 0.4291 0.4295
5 0.3639 0.3641
6 0.3525 0.3528
7 0.3509 0.3509
8 0.3463 0.3466
9 0.3449 0.3450
10 0.3437 0.3437
11 0.3428 0.3430
12 0.3202 0.3205
13 0.3184 0.3184
14 0.3162 0.3164
15 0.3132 0.3134
16 0.3015 0.3016
17 0.2957 0.2958
18 0.2876 0.2876
19 0.2838 0.2839
20 0.2743 0.2744
21 0.2676 0.2677
22 0.2620 0.2621
23 0.2605 0.2605
24 0.2578 0.2579
25 0.2573 0.2574
26 0.2563 0.2563
27 0.2543 0.2544
28 0.2504 0.2506
29 0.2440 0.2442
30 0.2438 0.2439
31 0.2434 0.2436
32 0.2393 0.2394
33 0.2386 0.2387
34 0.2366 0.2368
35 0.2299 0.2301
36 0.2286 0.2287
37 0.2275 0.2276
38 0.2238 0.2239
39 0.2228 0.2228
40 0.2171 0.2172
41 0.2102 0.2103
42 0.2098 0.2098
43 0.2095 0.2095
44 0.2086 0.2086
45 0.2083 0.2083
46 0.2056 0.2057
47 0.2055 0.2056
48 0.2048 0.2049
49 0.2007 0.2008
50 0.2000 0.2001
51 0.1939 0.1941
52 0.1915 0.1915
53 0.1889 0.1889
54 0.1867 0.1868
55 0.1854 0.1855
56 0.1849 0.1850
57 0.1773 0.1774
58 0.1749 0.1749
59 0.1739 0.1739
60 0.1711 0.1711
61 0.1600 0.1600
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:13:23 PM Page 12
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:13:23 PM Page 13
Duration Flows
The Facility PASSED
Flow(cfs)Predev Mit Percentage Pass/Fail
0.1234 1816 1816 100 Pass
0.1268 1684 1683 99 Pass
0.1302 1471 1473 100 Pass
0.1335 1361 1361 100 Pass
0.1369 1250 1251 100 Pass
0.1403 1111 1113 100 Pass
0.1437 1016 1018 100 Pass
0.1470 917 918 100 Pass
0.1504 857 857 100 Pass
0.1538 803 803 100 Pass
0.1572 726 726 100 Pass
0.1605 671 673 100 Pass
0.1639 618 618 100 Pass
0.1673 572 572 100 Pass
0.1707 539 542 100 Pass
0.1740 488 488 100 Pass
0.1774 451 451 100 Pass
0.1808 422 422 100 Pass
0.1842 389 389 100 Pass
0.1875 367 367 100 Pass
0.1909 343 343 100 Pass
0.1943 315 316 100 Pass
0.1977 297 297 100 Pass
0.2010 271 272 100 Pass
0.2044 256 256 100 Pass
0.2078 242 241 99 Pass
0.2112 221 222 100 Pass
0.2145 210 210 100 Pass
0.2179 198 198 100 Pass
0.2213 181 181 100 Pass
0.2247 171 171 100 Pass
0.2280 159 160 100 Pass
0.2314 148 149 100 Pass
0.2348 141 141 100 Pass
0.2382 135 135 100 Pass
0.2415 122 123 100 Pass
0.2449 115 115 100 Pass
0.2483 107 107 100 Pass
0.2517 105 105 100 Pass
0.2550 100 100 100 Pass
0.2584 92 92 100 Pass
0.2618 88 88 100 Pass
0.2652 83 83 100 Pass
0.2685 74 76 102 Pass
0.2719 71 71 100 Pass
0.2753 67 67 100 Pass
0.2787 65 65 100 Pass
0.2820 62 62 100 Pass
0.2854 59 59 100 Pass
0.2888 55 56 101 Pass
0.2922 53 54 101 Pass
0.2955 53 53 100 Pass
0.2989 50 50 100 Pass
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:13:23 PM Page 14
0.3023 47 47 100 Pass
0.3057 45 45 100 Pass
0.3090 40 40 100 Pass
0.3124 38 38 100 Pass
0.3158 34 35 102 Pass
0.3192 31 31 100 Pass
0.3225 29 29 100 Pass
0.3259 28 28 100 Pass
0.3293 25 25 100 Pass
0.3327 22 22 100 Pass
0.3360 21 21 100 Pass
0.3394 20 20 100 Pass
0.3428 17 18 105 Pass
0.3462 14 14 100 Pass
0.3495 12 12 100 Pass
0.3529 11 11 100 Pass
0.3563 9 9 100 Pass
0.3597 9 9 100 Pass
0.3631 9 9 100 Pass
0.3664 8 8 100 Pass
0.3698 8 8 100 Pass
0.3732 8 8 100 Pass
0.3766 8 8 100 Pass
0.3799 8 8 100 Pass
0.3833 8 8 100 Pass
0.3867 8 8 100 Pass
0.3901 8 8 100 Pass
0.3934 7 7 100 Pass
0.3968 7 7 100 Pass
0.4002 7 7 100 Pass
0.4036 7 7 100 Pass
0.4069 7 7 100 Pass
0.4103 6 6 100 Pass
0.4137 6 6 100 Pass
0.4171 6 6 100 Pass
0.4204 6 6 100 Pass
0.4238 6 6 100 Pass
0.4272 6 6 100 Pass
0.4306 5 5 100 Pass
0.4339 5 5 100 Pass
0.4373 4 4 100 Pass
0.4407 4 4 100 Pass
0.4441 3 3 100 Pass
0.4474 2 2 100 Pass
0.4508 2 2 100 Pass
0.4542 2 2 100 Pass
0.4576 2 2 100 Pass
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:13:23 PM Page 15
Water Quality
Water Quality BMP Flow and Volume for POC #1
On-line facility volume:0.0795 acre-feet
On-line facility target flow:0.1049 cfs.
Adjusted for 15 min:0.1049 cfs.
Off-line facility target flow:0.0592 cfs.
Adjusted for 15 min:0.0592 cfs.
15 - MIN OFF LINE WATER
QUALITY FLOW RATE FOR 4
- CARTRIDGE CONTECH
STORMFILTER FACILITY
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:13:23 PM Page 16
LID Report
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:14:20 PM Page 17
POC 2
+ Predeveloped x Mitigated
Predeveloped Landuse Totals for POC #2
Total Pervious Area:0
Total Impervious Area:0.062
Mitigated Landuse Totals for POC #2
Total Pervious Area:0
Total Impervious Area:0.062
Flow Frequency Method:Log Pearson Type III 17B
Flow Frequency Return Periods for Predeveloped. POC #2
Return Period Flow(cfs)
2 year 0.023638
5 year 0.029858
10 year 0.034084
25 year 0.039565
50 year 0.043761
100 year 0.048058
Flow Frequency Return Periods for Mitigated. POC #2
Return Period Flow(cfs)
2 year 0.023638
5 year 0.029858
10 year 0.034084
25 year 0.039565
50 year 0.043761
100 year 0.048058
Annual Peaks
Annual Peaks for Predeveloped and Mitigated. POC #2
Year Predeveloped Mitigated
1949 0.031 0.031
1950 0.033 0.033
1951 0.019 0.019
1952 0.017 0.017
1953 0.018 0.018
1954 0.019 0.019
1955 0.022 0.022
1956 0.021 0.021
1957 0.024 0.024
1958 0.020 0.020
1959 0.020 0.020
100 - YEAR PEAK
FLOW RATE FOR 1
- CARTRIDGE
CONTECH
STORMFILTER
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:14:51 PM Page 18
1960 0.020 0.020
1961 0.021 0.021
1962 0.018 0.018
1963 0.020 0.020
1964 0.020 0.020
1965 0.025 0.025
1966 0.017 0.017
1967 0.029 0.029
1968 0.033 0.033
1969 0.023 0.023
1970 0.022 0.022
1971 0.026 0.026
1972 0.027 0.027
1973 0.016 0.016
1974 0.024 0.024
1975 0.028 0.028
1976 0.019 0.019
1977 0.020 0.020
1978 0.025 0.025
1979 0.034 0.034
1980 0.030 0.030
1981 0.025 0.025
1982 0.035 0.035
1983 0.028 0.028
1984 0.018 0.018
1985 0.025 0.025
1986 0.021 0.021
1987 0.033 0.033
1988 0.020 0.020
1989 0.025 0.025
1990 0.042 0.042
1991 0.034 0.034
1992 0.018 0.018
1993 0.015 0.015
1994 0.017 0.017
1995 0.022 0.022
1996 0.023 0.023
1997 0.023 0.023
1998 0.023 0.023
1999 0.047 0.047
2000 0.023 0.023
2001 0.026 0.026
2002 0.030 0.030
2003 0.023 0.023
2004 0.044 0.044
2005 0.020 0.020
2006 0.018 0.018
2007 0.041 0.041
2008 0.033 0.033
2009 0.031 0.031
Ranked Annual Peaks
Ranked Annual Peaks for Predeveloped and Mitigated. POC #2
Rank Predeveloped Mitigated
1 0.0469 0.0469
2 0.0439 0.0439
3 0.0421 0.0421
4 0.0410 0.0410
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:14:51 PM Page 19
5 0.0348 0.0348
6 0.0337 0.0337
7 0.0337 0.0337
8 0.0331 0.0331
9 0.0331 0.0331
10 0.0330 0.0330
11 0.0328 0.0328
12 0.0306 0.0306
13 0.0306 0.0306
14 0.0302 0.0302
15 0.0299 0.0299
16 0.0289 0.0289
17 0.0284 0.0284
18 0.0276 0.0276
19 0.0271 0.0271
20 0.0263 0.0263
21 0.0257 0.0257
22 0.0251 0.0251
23 0.0250 0.0250
24 0.0247 0.0247
25 0.0246 0.0246
26 0.0246 0.0246
27 0.0243 0.0243
28 0.0240 0.0240
29 0.0234 0.0234
30 0.0233 0.0233
31 0.0233 0.0233
32 0.0229 0.0229
33 0.0228 0.0228
34 0.0226 0.0226
35 0.0220 0.0220
36 0.0219 0.0219
37 0.0218 0.0218
38 0.0214 0.0214
39 0.0214 0.0214
40 0.0208 0.0208
41 0.0201 0.0201
42 0.0201 0.0201
43 0.0201 0.0201
44 0.0200 0.0200
45 0.0200 0.0200
46 0.0197 0.0197
47 0.0196 0.0196
48 0.0196 0.0196
49 0.0192 0.0192
50 0.0191 0.0191
51 0.0186 0.0186
52 0.0184 0.0184
53 0.0181 0.0181
54 0.0179 0.0179
55 0.0177 0.0177
56 0.0177 0.0177
57 0.0170 0.0170
58 0.0168 0.0168
59 0.0167 0.0167
60 0.0164 0.0164
61 0.0153 0.0153
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:14:51 PM Page 20
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:14:51 PM Page 21
Duration Flows
The Facility PASSED
Flow(cfs)Predev Mit Percentage Pass/Fail
0.0118 1806 1806 100 Pass
0.0121 1636 1636 100 Pass
0.0125 1475 1475 100 Pass
0.0128 1345 1345 100 Pass
0.0131 1229 1229 100 Pass
0.0134 1102 1102 100 Pass
0.0138 1003 1003 100 Pass
0.0141 922 922 100 Pass
0.0144 852 852 100 Pass
0.0147 790 790 100 Pass
0.0150 726 726 100 Pass
0.0154 666 666 100 Pass
0.0157 610 610 100 Pass
0.0160 571 571 100 Pass
0.0163 533 533 100 Pass
0.0167 489 489 100 Pass
0.0170 451 451 100 Pass
0.0173 420 420 100 Pass
0.0176 389 389 100 Pass
0.0179 364 364 100 Pass
0.0183 338 338 100 Pass
0.0186 316 316 100 Pass
0.0189 296 296 100 Pass
0.0192 272 272 100 Pass
0.0196 256 256 100 Pass
0.0199 238 238 100 Pass
0.0202 221 221 100 Pass
0.0205 206 206 100 Pass
0.0209 193 193 100 Pass
0.0212 181 181 100 Pass
0.0215 171 171 100 Pass
0.0218 161 161 100 Pass
0.0221 148 148 100 Pass
0.0225 139 139 100 Pass
0.0228 135 135 100 Pass
0.0231 122 122 100 Pass
0.0234 113 113 100 Pass
0.0238 108 108 100 Pass
0.0241 105 105 100 Pass
0.0244 100 100 100 Pass
0.0247 92 92 100 Pass
0.0250 87 87 100 Pass
0.0254 84 84 100 Pass
0.0257 73 73 100 Pass
0.0260 71 71 100 Pass
0.0263 66 66 100 Pass
0.0267 63 63 100 Pass
0.0270 62 62 100 Pass
0.0273 58 58 100 Pass
0.0276 54 54 100 Pass
0.0280 54 54 100 Pass
0.0283 52 52 100 Pass
0.0286 50 50 100 Pass
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:14:51 PM Page 22
0.0289 46 46 100 Pass
0.0292 45 45 100 Pass
0.0296 40 40 100 Pass
0.0299 39 39 100 Pass
0.0302 33 33 100 Pass
0.0305 32 32 100 Pass
0.0309 29 29 100 Pass
0.0312 28 28 100 Pass
0.0315 25 25 100 Pass
0.0318 22 22 100 Pass
0.0321 21 21 100 Pass
0.0325 20 20 100 Pass
0.0328 17 17 100 Pass
0.0331 13 13 100 Pass
0.0334 12 12 100 Pass
0.0338 9 9 100 Pass
0.0341 9 9 100 Pass
0.0344 9 9 100 Pass
0.0347 9 9 100 Pass
0.0350 8 8 100 Pass
0.0354 8 8 100 Pass
0.0357 8 8 100 Pass
0.0360 8 8 100 Pass
0.0363 8 8 100 Pass
0.0367 8 8 100 Pass
0.0370 8 8 100 Pass
0.0373 7 7 100 Pass
0.0376 7 7 100 Pass
0.0380 7 7 100 Pass
0.0383 7 7 100 Pass
0.0386 7 7 100 Pass
0.0389 7 7 100 Pass
0.0392 6 6 100 Pass
0.0396 6 6 100 Pass
0.0399 6 6 100 Pass
0.0402 6 6 100 Pass
0.0405 6 6 100 Pass
0.0409 6 6 100 Pass
0.0412 5 5 100 Pass
0.0415 5 5 100 Pass
0.0418 4 4 100 Pass
0.0421 3 3 100 Pass
0.0425 3 3 100 Pass
0.0428 2 2 100 Pass
0.0431 2 2 100 Pass
0.0434 2 2 100 Pass
0.0438 2 2 100 Pass
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:14:51 PM Page 23
Water Quality
Water Quality BMP Flow and Volume for POC #2
On-line facility volume:0.0076 acre-feet
On-line facility target flow:0.01 cfs.
Adjusted for 15 min:0.01 cfs.
Off-line facility target flow:0.0056 cfs.
Adjusted for 15 min:0.0056 cfs.
15 - MIN WATER QUALITY FLOW
RATE FOR 1 - CARTRIDGE
CONTECH STORMFILTER
DRAFT2021-03-29 WWHM WQ FACILITY 3/30/2021 4:14:51 PM Page 24
LID Report
n
i
Stormwater Pollution Prevention Plan
For
Southport Park Avenue Extension:
Prepared For
Northwest Regional Office
3190 - 160th Avenue SE
Bellevue, WA 98008-5452
425-649-7000
Owner Developer Operator/Contractor
SECO Development, Inc. SECO Development, Inc. TBD
1083 Lake Washington
Boulevard North, #50
1083 Lake Washington
Boulevard North, #50
TBD
Renton, Washington 98056 Renton, Washington 98056 TBD
Project Site Location
Renton, Washington
Certified Erosion and Sediment Control Lead
TBD
SWPPP Prepared By
Coughlin Porter Lundeen
801 Second Ave Suite# 900
Seattle, WA 98104
(206) 343-0460
Ashton Huff, Civil Engineer
SWPPP Preparation Date
5/17/2019
Approximate Project Construction Dates
08-01-2019 to 01-01-2020
n
ii
Contents
1.0 Introduction ...............................................................................................................................1
2.0 Site Description ........................................................................................................................3
2.1 Existing Conditions ...........................................................................................................3
2.2 Proposed Construction Activities ......................................................................................3
3.0 Construction Stormwater BMPs ...............................................................................................5
3.1 The 12 BMP Elements .......................................................................................................5
3.1.1 Element #1 – Mark Clearing Limits ...................................................................5
3.1.2 Element #2 – Establish Construction Access .....................................................5
3.1.3 Element #3 – Control Flow Rates .......................................................................6
3.1.4 Element #4 – Install Sediment Controls .............................................................6
3.1.5 Element #5 – Stabilize Soils ...............................................................................7
3.1.6 Element #6 – Protect Slopes ...............................................................................8
3.1.7 Element #7 – Protect Drain Inlets .......................................................................8
3.1.8 Element #8 – Stabilize Channels and Outlets .....................................................9
3.1.9 Element #9 – Control Pollutants .........................................................................9
3.1.10 Element #10 – Control Dewatering .................................................................11
3.1.11 Element #11 – Maintain BMPs .......................................................................11
3.1.12 Element #12 – Manage the Project ..................................................................11
5.0 Pollution Prevention Team ......................................................................................................17
5.1 Roles and Responsibilities ...............................................................................................17
5.2 Team Members ................................................................................................................17
6.0 Site Inspections and Monitoring .............................................................................................19
6.1 Site Inspection .................................................................................................................19
6.1.1 Site Inspection Frequency ................................................................................19
6.1.2 Site Inspection Documentation .........................................................................19
6.2 Stormwater Quality Monitoring ......................................................................................20
6.2.2 pH Sampling .....................................................................................................20
7.0 Reporting and Recordkeeping ................................................................................................23
7.1 Recordkeeping .................................................................................................................23
7.1.1 Site Log Book ...................................................................................................23
7.1.2 Records Retention.............................................................................................23
7.1.3 Access to Plans and Records ............................................................................23
7.1.4 Updating the SWPPP ........................................................................................23
7.2 Reporting .........................................................................................................................24
7.2.1 Discharge Monitoring Reports .........................................................................24
7.2.2 Notification of Noncompliance ........................................................................24
7.2.3 Permit Application and Changes ......................................................................24
n
iii
Appendix A – Site Plans .........................................................................................................25
Appendix B – Construction BMPs .........................................................................................26
Appendix C – Alternative BMPs ............................................................................................27
Appendix D – General Permit ................................................................................................29
Appendix E – Site Inspection Forms (and Site Log) ..............................................................30
Appendix F – Engineering Calculations .................................................................................39
Appendix A Site plans
Appendix B Construction BMPs
Appendix C Alternative Construction BMP list
Appendix D General Permit
Appendix E Site Log and Inspection Forms
Appendix F Engineering Calculations
Stormwater Pollution Prevention Plan
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1.0 Introduction
This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the NPDES
stormwater permit requirements for the Southport Park Avenue Extension construction project in
Renton, Washington. The site is situated at the southern tip of Lake Washington to the west of
the Gene Coulon Memorial Beach Park. The site is in the NW ¼ of the NW ¼ of Section 8,
Township 23 North, Range 5 East, Willamette Meridian. The site will occupy parcels
082305917807 and 082305919100, with an area of 439,578-SF. The existing site consists of
1.56 acres of entirely impervious area. Overall, the proposed project will include roadway
paving, concrete sidewalk, catch basins, and a Contech Solutions StormFilter catch basin for
water quality purposes.
The proposed conditions will consist of approximately 1.56 acres of impervious area.
Construction activities will include demolition, excavation, grading, and relocation of onsite
utilities. The purpose of this SWPPP is to describe the proposed construction activities and all
temporary and permanent erosion and sediment control (TESC) measures, pollution prevention
measures, inspection/monitoring activities, and recordkeeping that will be implemented during
the proposed construction project. The objectives of the SWPPP are to:
1. Implement Best Management Practices (BMPs) to prevent erosion and
sedimentation, and to identify, reduce, eliminate or prevent stormwater
contamination and water pollution from construction activity.
2. Prevent violations of surface water quality, ground water quality, or
sediment management standards.
3. Prevent, during the construction phase, adverse water quality impacts
including impacts on beneficial uses of the receiving water by controlling
peak flow rates and volumes of stormwater runoff at the Permittee’s
outfalls and downstream of the outfalls.
This SWPPP was prepared using the Ecology SWPPP Template downloaded from the Ecology
website. This SWPPP was prepared based on the requirements set forth in the Construction
Stormwater General Permit and Stormwater Management Manual for Western Washington
(SWMMWW 2005). The report is divided into seven main sections with several appendices that
include stormwater related reference materials. The topics presented in the each of the main
sections are:
Section 1 – INTRODUCTION. This section provides a summary
description of the project, and the organization of the SWPPP document.
Stormwater Pollution Prevention Plan
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Section 2 – SITE DESCRIPTION. This section provides a detailed
description of the existing site conditions, proposed construction activities,
and calculated stormwater flow rates for existing conditions and post–
construction conditions.
Section 3 – CONSTRUCTION BMPs. This section provides a detailed
description of the BMPs to be implemented based on the 12 required
elements of the SWPPP.
Section 4 – CONSTRUCTION PHASING AND BMP
IMPLEMENTATION. This section provides a description of the timing
of the BMP implementation in relation to the project schedule.
Section 5 – POLLUTION PREVENTION TEAM. This section identifies
the appropriate contact names (emergency and non-emergency),
monitoring personnel, and the onsite temporary erosion and sedimentation
control inspector
Section 6 – INSPECTION AND MONITORING. This section provides a
description of the inspection and monitoring requirements such as the
parameters of concern to be monitored, sample locations, sample
frequencies, and sampling methods for all stormwater discharge locations
from the site.
Section 7 – RECORDKEEPING. This section describes the requirements
for documentation of the BMP implementation, site inspections,
monitoring results, and changes to the implementation of certain BMPs
due to site factors experienced during construction.
Supporting documentation and standard forms are provided in the following Appendices:
Appendix A – Site plans
Appendix B – Construction BMPs
Appendix C – Alternative Construction BMP list
Appendix D – General Permit
Appendix E – Site Log and Inspection Forms
Appendix F – Engineering Calculations
Stormwater Pollution Prevention Plan
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2.0 Site Description
2.1 Existing Conditions
The existing site consists of asphalt and gravel. The site was previously home to the Shuffleton
Steam Plant, which was built in the 1930’s and demolished in 2001.
The site is situated at the southern tip of Lake Washington to the west of the Gene Coulon
Memorial Beach Park. The site is in the NW ¼ of the NW ¼ of Section 8, Township 23 North,
Range 5 East, Willamette Meridian. The site will occupy parcels 082305917807 and
082305919100, with an area of 439,578-SF. The area of disturbance is 1.56 acres in size and
includes a roadway portion, concrete sidewalk, and grassed area. The topography of the site and
surrounding properties gently slopes to the northwest with approximately three feet of elevation
change. Per the geotechnical report provided for the public Park Avenue extension project, soil
depth and thickness vary throughout the site. Generally, the site is loose to medium silty sand.
Groundwater lies as high as four feet below existing grade in some areas.
Runoff from the site generally sheet flows to the north side of the site, into the existing PSE
storm system, ultimately discharging directly to Lake Washington. Based on city of Renton GIS
data and available survey information, the southwest portion of the site, located southwest of the
proposed road and just north of existing 757th Avenue, currently drains west to the adjacent
Boeing property and then to Lake Washington.
There are no critical areas on the site such as high erosion risk areas, wetlands, streams, or steep
slopes (potential landslide area). The project site is, however, a seismic hazard area, according to
City of Renton map data.
2.2 Proposed Construction Activities
Overall, the project will include additional roadway paving, concrete sidewalk, catch basins, a
Contech Solutions StormFilter catch basin, and light poles.
Construction activities will include site preparation, TESC installation, demolition of the existing
asphalt on site, concrete sidewalk construction, site-wide grading, asphalt paving, and seeding of
unpaved areas. The schedule and phasing of BMPs during construction is provided in Section
4.0.
Stormwater runoff volumes were calculated using the computer software WWHM2012. Basic
Water Quality Treatment will be provided by the Contech Solutions StormFilter catch basin.
The peak flows are based on the developed conditions after construction.
Stormwater Pollution Prevention Plan
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3.0 Construction Stormwater BMPs
3.1 The 12 BMP Elements
3.1.1 Element #1 – 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. The BMPs relevant to marking the clearing
limits that will be applied for this project include:
· High Visibility Plastic or Metal Fence (BMP C103)
Alternate BMPs for marking clearing limits are included in Appendix C as a quick reference tool
for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or
inappropriate during construction to satisfy the requirements set forth in the General NPDES
Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a
violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the
Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or
more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are
ineffective or failing.
3.1.2 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. The
specific BMPs related to establishing construction access that will be used on this project
include:
· Stabilized Construction Entrance (BMP C105)
· Wheel Wash (BMP C106)
· Construction Road/Parking Area Stabilization (BMP C107)
Alternate construction access BMPs are included in Appendix C as a quick reference tool for the
onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate
during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix
D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the
NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and
Sediment Control Lead will promptly initiate the implementation of one or more of the
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alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or
failing.
3.1.3 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. The specific BMPs for flow control that shall be used
on this project include:
No BMPs to be implemented.
Alternate flow control BMPs are included in Appendix C as a quick reference tool for the onsite
inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during
construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D).
To avoid potential erosion and sediment control issues that may cause a violation(s) of the
NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and
Sediment Control Lead will promptly initiate the implementation of one or more of the
alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or
failing.
The project site is located west of the Cascade Mountain Crest. As such, the project must
comply with Minimum Requirement 7 (Ecology 2005).
In general, discharge rates of stormwater from the site will be controlled where increases in
impervious area or soil compaction during construction could lead to downstream erosion, or
where necessary to meet local agency stormwater discharge requirements (e.g. discharge to
combined sewer systems).
3.1.4 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.
The specific BMPs to be used for controlling sediment on this project include:
· Detention Pond Or Vault
· Storm Drain Inlet Protection (BMP C220)
Alternate sediment control BMPs are included in Appendix C as a quick reference tool for the
onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate
during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix
D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the
NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and
Sediment Control Lead will promptly initiate the implementation of one or more of the
Stormwater Pollution Prevention Plan
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alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or
failing.
In addition, 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.
Whenever possible, sediment laden water shall be discharged into onsite, relatively level,
vegetated areas (BMP C240 paragraph 5, page 4-102).
In some cases, sediment discharge in concentrated runoff can be controlled using permanent
stormwater BMPs (e.g., infiltration swales, ponds, trenches). Sediment loads can limit the
effectiveness of some permanent stormwater BMPs, such as those used for infiltration or
biofiltration; however, those BMPs designed to remove solids by settling (wet ponds or detention
ponds) can be used during the construction phase. When permanent stormwater BMPs will be
used to control sediment discharge during construction, the structure will be protected from
excessive sedimentation with adequate erosion and sediment control BMPs. Any accumulated
sediment shall be removed after construction is complete and the permanent stormwater BMP
will be restabilized with vegetation per applicable design requirements.
The following BMPs will be implemented as end-of-pipe sediment controls as required to meet
permitted turbidity limits in the site discharge(s). Prior to the implementation of these
technologies, sediment sources and erosion control and soil stabilization BMP efforts will be
maximized to reduce the need for end-of-pipe sedimentation controls.
Temporary Sediment Pond (BMP C241)
Construction Stormwater Filtration (BMP C251)
Construction Stormwater Chemical Treatment (BMP C 250)
(implemented only with prior written approval from Ecology).
3.1.5 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. The specific BMPs for soil stabilization that shall be
used on this project include:
· Temporary and Permanent Seeding (BMP C120)
Alternate soil stabilization BMPs are included in Appendix C as a quick reference tool for the
onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate
Stormwater Pollution Prevention Plan
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during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix
D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the
NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and
Sediment Control Lead will promptly initiate the implementation of one or more of the
alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or
failing.
The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain
exposed and unworked for more than 7 days during the dry season (May 1 to September 30) and
2 days during the wet season (October 1 to April 30). Regardless of the time of year, all soils
shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather
forecasts.
In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be
temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion,
protected with sediment trapping measures, and where possible, be located away from storm
drain inlets, waterways, and drainage channels.
3.1.6 Element #6 – Protect Slopes
All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes
erosion. The following specific BMPs will be used to protect slopes for this project:
· Temporary and Permanent Seeding (BMP C120)
Alternate slope protection BMPs are included in Appendix C as a quick reference tool for the
onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate
during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix
D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the
NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and
Sediment Control Lead will promptly initiate the implementation of one or more of the
alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or
failing.
3.1.7 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. The following inlet protection measures
will be applied on this project:
Stormwater Pollution Prevention Plan
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Drop Inlet Protection
· Catch Basin Filters
If the BMP options listed above are deemed ineffective or inappropriate during construction to
satisfy the requirements set forth in the General NPDES Permit (Appendix D), or if no BMPs are
listed above but deemed necessary during construction, the Certified Erosion and Sediment
Control Lead shall implement one or more of the alternative BMP inlet protection options listed
in Appendix C.
3.1.8 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. The specific BMPs for
channel and outlet stabilization that shall be used on this project include:
No BMPs to be implemented
Alternate channel and outlet stabilization BMPs are included in Appendix C as a quick reference
tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or
inappropriate during construction to satisfy the requirements set forth in the General NPDES
Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a
violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the
Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or
more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are
ineffective or failing.
The project site is located west of the Cascade Mountain Crest. As such, all temporary on-site
conveyance channels shall be designed, constructed, and stabilized to prevent erosion from the
expected peak 10 minute velocity of flow from a Type 1A, 10-year, 24-hour recurrence interval
storm for the developed condition. Alternatively, the 10-year, 1-hour peak flow rate indicated by
an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used.
Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent
streambanks, slopes, and downstream reaches shall be provided at the outlets of all conveyance
systems.
3.1.9 Element #9 – Control Pollutants
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. If required, BMPs to be implemented to control specific
sources of pollutants are discussed below.
Stormwater Pollution Prevention Plan
10
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).
Sanitary wastewater:
Portable sanitation facilities will be firmly secured, regularly maintained,
and emptied when necessary.
Stormwater Pollution Prevention Plan
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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).
Solid Waste:
Solid waste will be stored in secure, clearly marked containers.
The facility does not require a Spill Prevention, Control, and Countermeasure (SPCC) Plan under
the Federal regulations of the Clean Water Act (CWA).
3.1.10 Element #10 – Control Dewatering
Dewatering will not occur with this project.
3.1.11 Element #11 – Maintain BMPs
All temporary and permanent erosion and sediment control BMPs shall be maintained and
repaired as needed to assure continued performance of their intended function. Maintenance and
repair shall be conducted in accordance with each particular BMPs specifications (attached).
Visual monitoring of the BMPs 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 will be reduced to once every
month.
All temporary erosion and sediment control BMPs shall be removed within 30 days after the
final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped
sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs
or vegetation shall be permanently stabilized.
3.1.12 Element #12 – Manage the Project
Erosion and sediment control BMPs for this project have been designed based on the following
principles:
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.
Stormwater Pollution Prevention Plan
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Thoroughly monitor site and maintain all ESC measures.
Schedule major earthwork during the dry season.
In addition, project management will incorporate the key components listed below:
As this project site is located west of the Cascade Mountain Crest, the project will be managed
according to the following key project components:
Phasing of Construction
The construction project is being phased to the extent practicable in order
to prevent soil erosion, and, to the maximum extent possible, the transport
of sediment from the site during construction.
Revegetation of exposed areas and maintenance of that vegetation shall be
an integral part of the clearing activities during each phase of construction,
per the Scheduling BMP (C 162).
Seasonal Work Limitations
From October 1 through April 30, clearing, grading, and other soil
disturbing activities shall only be permitted if shown to the satisfaction of
the local permitting authority that silt-laden runoff will be prevented from
leaving the site through a combination of the following:
Site conditions including existing vegetative coverage, slope, soil
type, and proximity to receiving waters; and
Limitations on activities and the extent of disturbed areas; and
Proposed erosion and sediment control measures.
Based on the information provided and/or local weather conditions, the
local permitting authority may expand or restrict the seasonal limitation on
site disturbance.
The following activities are exempt from the seasonal clearing and grading
limitations:
Routine maintenance and necessary repair of erosion and sediment
control BMPs;
Stormwater Pollution Prevention Plan
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Routine maintenance of public facilities or existing utility
structures that do not expose the soil or result in the removal of the
vegetative cover to soil; and
Activities where there is 100 percent infiltration of surface water
runoff within the site in approved and installed erosion and
sediment control facilities.
Coordination with Utilities and Other Jurisdictions
Care has been taken to coordinate with utilities, other construction
projects, and the local jurisdiction in preparing this SWPPP and
scheduling the construction work.
Inspection and Monitoring
All BMPs shall be inspected, maintained, and repaired as needed to assure
continued performance of their intended function. Site inspections shall
be conducted by a person who is knowledgeable in the principles and
practices of erosion and sediment control. This person has the necessary
skills to:
Assess the site conditions and construction activities that could
impact the quality of stormwater, and
Assess the effectiveness of erosion and sediment control measures
used to control the quality of stormwater discharges.
A Certified Erosion and Sediment Control Lead shall be on-site or on-call
at all times.
Whenever inspection and/or monitoring reveals that the BMPs identified
in this SWPPP are inadequate, due to the actual discharge of or potential
to discharge a significant amount of any pollutant, appropriate BMPs or
design changes shall be implemented as soon as possible.
Maintaining an Updated Construction SWPPP
This SWPPP shall be retained on-site or within reasonable access to the
site.
The SWPPP shall be modified whenever there is a change in the 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.
Stormwater Pollution Prevention Plan
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The SWPPP shall be modified if, during inspections or investigations
conducted by the owner/operator, or the applicable local or state
regulatory authority, it is determined that the SWPPP is ineffective in
eliminating or significantly minimizing pollutants in stormwater
discharges from the site. The SWPPP shall be modified as necessary to
include additional or modified BMPs designed to correct problems
identified. Revisions to the SWPPP shall be completed within seven (7)
days following the inspection.
Alternate dewatering control BMPs are included in Appendix C as a quick reference tool
for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or
inappropriate during construction to satisfy the requirements set forth in the General
NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues
that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided
in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate
the implementation of one or more of the alternative BMPs listed in Appendix C after the
first sign that existing BMPs are ineffective or failing.
Stormwater Pollution Prevention Plan
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4.0 Construction Phasing and BMP
Implementation
The BMP implementation schedule will be driven by the construction schedule. The following
provides a sequential list of the proposed construction schedule milestones and the corresponding
BMP implementation schedule. The list contains key milestones such as wet season
construction.
The BMP implementation schedule listed below is keyed to proposed phases of the construction
project and reflects differences in BMP installations and inspections that relate to wet season
construction. The project site is located west of the Cascade Mountain Crest. As such, the dry
season is considered to be from May 1 to September 30 and the wet season is considered to be
from October 1 to April 30.
Estimate of Construction start date: TBD
Estimate of Construction finish date: TBD
Mobilize equipment on site: TBD
Mobilize and store all ESC and soil stabilization products
(store materials on hand BMP C150): TBD
Install ESC measures: TBD
Install stabilized construction entrance: TBD
Begin clearing and grubbing: TBD
Soil stabilization on excavated sideslopes (in idle, no
work areas as shown on ESC plans) TBD
Temporary erosion control measures (hydroseeding) TBD
Site inspections reduced to monthly: TBD
Begin concrete pour and implement BMP C151: TBD
Excavate and install new utilities and services (Phase 1): TBD
Begin building construction: TBD
Complete Phase 1 utility construction TBD
Stormwater Pollution Prevention Plan
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Begin implementing soil stabilization and sediment
control BMPs throughout the site in preparation for wet
season: TBD
Wet Season starts: 10 / 01 / 2019
Site inspections and monitoring conducted weekly and
for applicable rain events as detailed in Section 6 of this
SWPPP: TBD
Implement Element #12 BMPs and manage site to
minimize soil disturbance during the wet season TBD
No site work such as grading or excavation planned:
Dry Season starts: 05 / 01 / 2020
Site grading begins: TBD
Excavate and install new utilities and services (Phase 2): TBD
Site grading ends: TBD
Permanent erosion control measures (hydroseeding): TBD
Stormwater Pollution Prevention Plan
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5.0 Pollution Prevention Team
5.1 Roles and Responsibilities
The pollution prevention team consists of personnel responsible for implementation of the
SWPPP, including the following:
Certified Erosion and Sediment Control Lead (CESCL) – primary
contractor contact, responsible for site inspections (BMPs, visual
monitoring, sampling, etc.); to be called upon in case of failure of any
ESC measures.
Resident Engineer – For projects with engineered structures only
(sediment ponds/traps, sand filters, etc.): site representative for the owner
that is the project's supervising engineer responsible for inspections and
issuing instructions and drawings to the contractor's site supervisor or
representative
Emergency Ecology Contact – individual to be contacted at Ecology in
case of emergency.
Emergency Owner Contact – individual that is the site owner or
representative of the site owner to be contacted in the case of an
emergency.
Non-Emergency Ecology Contact – individual that is the site owner or
representative of the site owner than can be contacted if required.
Monitoring Personnel – personnel responsible for conducting water
quality monitoring; for most sites this person is also the Certified Erosion
and Sediment Control Lead.
5.2 Team Members
Names and contact information for those identified as members of the pollution prevention team
are provided in the following table.
Title Name(s) Phone Number
Certified Erosion and Sediment Control Lead (CESCL) TBD TBD
Resident Engineer Tim Brockway, P.E. (206) 343-0460
Emergency Ecology Contact TBD TBD
Emergency Owner Contact TBD TBD
Stormwater Pollution Prevention Plan
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Non-Emergency Ecology Contact TBD TBD
Monitoring Personnel TBD TBD
Stormwater Pollution Prevention Plan
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6.0 Site Inspections and Monitoring
Monitoring includes visual inspection, monitoring for water quality parameters of concern, and
documentation of the inspection and monitoring 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; and,
Stormwater quality monitoring.
For convenience, the inspection form and water quality monitoring forms included in this
SWPPP include the required information for the site log book. This SWPPP may function as the
site log book if desired, or the forms may be separated and included in a separate site log book.
However, if separated, the site log book but must be maintained on-site or within reasonable
access to the site and be made available upon request to Ecology or the local jurisdiction.
6.1 Site Inspection
All BMPs will be inspected, maintained, and repaired as needed to assure continued performance
of their intended function. The inspector will be a Certified Erosion and Sediment Control Lead
(CESCL) per BMP C160. The name and contact information for the CESCL is provided in
Section 5 of this SWPPP.
Site inspection will occur in all areas disturbed by construction activities and at all stormwater
discharge points. Stormwater will be examined for the presence of suspended sediment,
turbidity, discoloration, and oily sheen. The site inspector will evaluate and document the
effectiveness of the installed BMPs and determine if it is necessary to repair or replace any of the
BMPs to improve the quality of stormwater discharges. All maintenance and repairs will be
documented in the site log book or forms provided in this document. All new BMPs or design
changes will be documented in the SWPPP as soon as possible.
6.1.1 Site Inspection Frequency
Site inspections will be conducted at least once a week and within 24 hours following any
discharge from the site. For sites with temporary stabilization measures, the site inspection
frequency can be reduced to once every month.
6.1.2 Site Inspection Documentation
The site inspector will record each site inspection using the site log inspection forms provided in
Appendix E. The site inspection log forms may be separated from this SWPPP document, but
Stormwater Pollution Prevention Plan
20
will be maintained on-site or within reasonable access to the site and be made available upon
request to Ecology or the local jurisdiction.
6.2 Stormwater Quality Monitoring
Monitoring requirements for the proposed project will include either turbidity or water
transparency sampling to monitor site discharges for water quality compliance with the 2005
Construction Stormwater General Permit (Appendix D). Sampling will be conducted at all
discharge points at least once per calendar week.
Turbidity or transparency monitoring will follow the analytical methodologies described in
Section S4 of the 2005 Construction Stormwater General Permit (Appendix D). The key
benchmark turbidity value is 25 nephelometric turbidity units (NTU) for the downstream
receiving water body. If the 25 NTU benchmark is exceeded in any sample collected from CB5,
the following steps will be conducted:
1. Ensure all BMPs specified in this SWPPP are installed and functioning as
intended.
2. Assess whether additional BMPs should be implemented, and document
modified BMPs in the SWPPP as necessary.
3. Sample discharge daily until the discharge is 25 NTU or lower.
If the turbidity exceeds 250 NTU at any time, the following steps will be conducted:
1. Notify Ecology by phone within 24 hours of analysis (see Section 5.0 of
this SWPPP for contact information).
2. Continue sampling daily until the discharge is 25 NTU or lower Initiate
additional treatment BMPs such as off-site treatment, infiltration, filtration
and chemical treatment within 24 hours, and implement those additional
treatment BMPs as soon as possible, but within a minimum of 7 days.
3. Describe inspection results and remedial actions taken in the site log book
and in monthly discharge monitoring reports as described in Section 7.0 of
this SWPPP.
6.2.2 pH Sampling
Stormwater runoff will be monitored for pH starting on the first day of any activity that includes
more than 40 yards of poured or recycled concrete, or after the application of “Engineered Soils”
such as, Portland cement treated base, cement kiln dust, or fly ash. This does not include
fertilizers. For concrete work, pH monitoring will start the first day concrete is poured and
Stormwater Pollution Prevention Plan
21
continue until 3 weeks after the last pour. For engineered soils, the pH monitoring period begins
when engineered soils are first exposed to precipitation and continue until the area is fully
stabilized.
Stormwater samples will be collected weekly from all points of discharge from the site and
measured for pH using a calibrated pH meter, pH test kit, or wide range pH indicator paper. If
the measured pH is 8.5 or greater, the following steps will be conducted:
1. Prevent the high pH water from entering storm drains or surface water.
2. Adjust or neutralize the high pH water if necessary using appropriate
technology such as CO2 sparging (liquid or dry ice).
3. Contact Ecology if chemical treatment other than CO2 sparging is planned.
Stormwater Pollution Prevention Plan
23
7.0 Reporting and Recordkeeping
7.1 Recordkeeping
7.1.1 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; and,
Stormwater quality monitoring.
For convenience, the inspection form and water quality monitoring forms included in this
SWPPP include the required information for the site log book.
7.1.2 Records Retention
Records of all monitoring information (site log book, inspection reports/checklists, etc.), this
Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit
requirements will be retained during the life of the construction project and for a minimum of
three years following the termination of permit coverage in accordance with permit condition
S5.C.
7.1.3 Access to Plans and Records
The SWPPP, General Permit, Notice of Authorization letter, and Site Log Book will be retained
on site or within reasonable access to the site and will be made immediately available upon
request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology
within 14 days of receipt of a written request for the SWPPP from Ecology. Any other
information requested by Ecology will be submitted within a reasonable time. A copy of the
SWPPP or access to the SWPPP will be provided to the public when requested in writing in
accordance with permit condition S5.G.
7.1.4 Updating the SWPPP
In accordance with Conditions S3, S4.B, and S9.B.3 of the General Permit, this SWPPP will be
modified if the SWPPP is ineffective in eliminating or significantly minimizing pollutants in
stormwater discharges from the site or there has been a change in design, construction, operation,
or maintenance at the site that has a significant effect on the discharge, or potential for discharge,
of pollutants to the waters of the State. The SWPPP will be modified within seven days of
determination based on inspection(s) that additional or modified BMPs are necessary to correct
problems identified, and an updated timeline for BMP implementation will be prepared.
Stormwater Pollution Prevention Plan
24
7.2 Reporting
7.2.1 Discharge Monitoring Reports
If cumulative soil disturbance is 5 acres or larger: Discharge Monitoring Reports (DMRs) will be
submitted to Ecology monthly. Of there was no discharge during a given monitoring period, the
Permittee shall submit the form as required, with the words “No discharge” entered in the place
of monitoring results. The DMR due date is 15 days following the end of each month.
7.2.2 Notification of Noncompliance
If any of the terms and conditions of the permit are not met, and it causes a threat to human
health or the environment, the following steps will be taken in accordance with permit section
S5.F:
1. Ecology will be immediately notified of the failure to comply.
2. Immediate action will be taken to control the noncompliance issue and to
correct the problem. 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.
7.2.3 Permit Application and Changes
In accordance with permit condition S2.A, a complete application form will be submitted to
Ecology and the appropriate local jurisdiction (if applicable) to be covered by the General
Permit.
Stormwater Pollution Prevention Plan
25
Appendix A – Site Plans
Stormwater Pollution Prevention Plan
26
Appendix B – Construction BMPs
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.
l As required by local governments.
l 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 gen-
erally used to remove unwanted vegetation.The points to remember when attempting to
save individual plants are:
l 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 veget-
ation and trees.
l 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:
l 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.
l 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 usu-
ally 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
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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 neces-
sary 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.
l 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 pre-
serve most of the important feeder roots.
Some problems that can be encountered with a few specific trees are:
l 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.
l 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.
l 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.
l Thinning operations in pure or mixed stands of Grand fir,Pacific silver fir,Noble fir,
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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.
l If tree roots have been exposed or injured,“prune”cleanly with an appropriate prun-
ing 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 C102:Buffer Zones
Purpose
Creation of an undisturbed area or strip of natural vegetation or an established suitable
planting that will provide a living filter to reduce soil erosion and runoff velocities.
Conditions of Use
Natural buffer zones are used along streams,wetlands and other bodies of water that
need protection from erosion and sedimentation.Vegetative buffer zones can be used to
protect natural swales and can be incorporated into the natural landscaping of an area.
Critical-areas buffer zones should not be used as sediment treatment areas.These
areas shall remain completely undisturbed.The local permitting authority may expand
the buffer widths temporarily to allow the use of the expanded area for removal of sed-
iment.
Design and Installation Specifications
l Preserving natural vegetation or plantings in clumps,blocks,or strips is generally
the easiest and most successful method.
l Leave all unstable steep slopes in natural vegetation.
l Mark clearing limits and keep all equipment and construction debris out of the nat-
ural areas and buffer zones.Steel construction fencing is the most effective method
in protecting sensitive areas and buffers.Alternatively,wire-backed silt fence on
steel posts is marginally effective.Flagging alone is typically not effective.
l Keep all excavations outside the dripline of trees and shrubs.
l Do not push debris or extra soil into the buffer zone area because it will cause
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Volume II -Chapter 4 -Page 268
damage from burying and smothering.
l Vegetative buffer zones for streams,lakes or other waterways shall be established
by the local permitting authority or other state or federal permits or approvals.
Maintenance Standards
Inspect the area frequently to make sure flagging remains in place and the area remains
undisturbed.Replace all damaged flagging immediately.
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 pro-
tection.
Conditions of Use
To establish clearing limits plastic,fabric,or metal fence may be used:
l At the boundary of sensitive areas,their buffers,and other areas required to be left
uncleared.
l 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 sag-
ging 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 (p.367)to
act as high visibility fence.Silt fence shall be at least 3 feet high and must be highly vis-
ible to meet the requirements of this BMP.
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Volume II -Chapter 4 -Page 269
Metal fences shall be designed and installed according to the manufacturer's spe-
cifications.
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 suf-
ficient 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 (p.273)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 sta-
bilization because these products raise pH levels in stormwater and concrete discharge
to surface waters of the State is prohibited.
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Volume II -Chapter 4 -Page 270
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)
l 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.
l Fencing (see BMP C103:High Visibility Fence (p.269))shall be installed as neces-
sary to restrict traffic to the construction entrance.
l Whenever possible,the entrance shall be constructed on a firm,compacted sub-
grade.This can substantially increase the effectiveness of the pad and reduce the
need for maintenance.
l 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 spe-
cifications.
l 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.
l Any sediment that is tracked onto pavement shall be removed by shoveling or
street sweeping.The sediment collected by sweeping shall be removed or sta-
bilized 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 con-
tain the wash water shall be considered.The sediment would then be washed into
the sump where it can be controlled.
l 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.
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l Any quarry spalls that are loosened from the pad,which end up on the roadway
shall be removed immediately.
l 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.
l Upon project completion and site stabilization,all construction accesses intended
as permanent access for maintenance shall be permanently stabilized.
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Figure II-4.1.1 Stabilized Construction Entrance
DEP A RTMENT OF
ECOLOG Y
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
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Volume II -Chapter 4 -Page 273
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C105:Stab-
ilized 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 con-
sideration 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 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 (p.270))is not preventing sediment from being tracked onto pavement.
l 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.
l Pressure washing combined with an adequately sized and surfaced pad with dir-
ect drainage to a large 10-foot x 10-foot sump can be very effective.
l Discharge wheel wash or tire bath wastewater to a separate on-site treatment sys-
tem 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.
l 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 (p.276).The Local Per-
mitting 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.
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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.
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Volume II -Chapter 4 -Page 275
Figure II-4.1.2 Wheel Wash
DEP A RTMENT OF
ECOLOG Y
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
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BMP C107:Construction Road/Parking Area Stabilization
Purpose
Stabilizing subdivision roads,parking areas,and other on-site vehicle transportation
routes immediately after grading reduces erosion caused by construction traffic or runoff.
Conditions of Use
Roads or parking areas shall be stabilized wherever they are constructed,whether per-
manent or temporary,for use by construction traffic.
l High Visibility Fencing (see BMP C103:High Visibility Fence (p.269))shall be
installed,if necessary,to limit the access of vehicles to only those roads and park-
ing areas that are stabilized.
Design and Installation Specifications
l On areas that will receive asphalt as part of the project,install the first lift as soon
as possible.
l A 6-inch depth of 2-to 4-inch crushed rock,gravel base,or crushed surfacing base
course shall be applied immediately after grading or utility installation.A 4-inch
course of asphalt treated base (ATB)may also be used,or the road/parking area
may be paved.It may also be possible to use cement or calcium chloride for soil
stabilization.If cement or cement kiln dust is used for roadbase stabilization,pH
monitoring and BMPs (BMP C252:High pH Neutralization Using CO2 (p.409)and
BMP C253:pH Control for High pH Water (p.412))are necessary to evaluate and
minimize the effects on stormwater.If the area will not be used for permanent
roads,parking areas,or structures,a 6-inch depth of hog fuel may also be used,
but this is likely to require more maintenance.Whenever possible,construction
roads and parking areas shall be placed on a firm,compacted subgrade.
l Temporary road gradients shall not exceed 15 percent.Roadways shall be care-
fully graded to drain.Drainage ditches shall be provided on each side of the road-
way in the case of a crowned section,or on one side in the case of a super-
elevated section.Drainage ditches shall be directed to a sediment control BMP.
l Rather than relying on ditches,it may also be possible to grade the road so that run-
off sheet-flows into a heavily vegetated area with a well-developed topsoil.Land-
scaped areas are not adequate.If this area has at least 50 feet of vegetation that
water can flow through,then it is generally preferable to use the vegetation to treat
runoff,rather than a sediment pond or trap.The 50 feet shall not include wetlands
or their buffers.If runoff is allowed to sheetflow through adjacent vegetated areas,it
is vital to design the roadways and parking areas so that no concentrated runoff is
created.
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l Storm drain inlets shall be protected to prevent sediment-laden water entering the
storm drain system (see BMP C220:Storm Drain Inlet Protection (p.357)).
Maintenance Standards
Inspect stabilized areas regularly,especially after large storm events.
Crushed rock,gravel base,etc.,shall be added as required to maintain a stable driving
surface and to stabilize any areas that have eroded.
Following construction,these areas shall be restored to pre-construction condition or bet-
ter to prevent future erosion.
Perform street cleaning at the end of each day or more often if necessary.
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.
l Mulch is required at all times for seeding because it protects seeds from heat,mois-
ture loss,and transport due to runoff.Mulch can be applied on top of the seed or
simultaneously by hydroseeding.See BMP C121:Mulching (p.284)for spe-
cifications.
l Seed and mulch,all disturbed areas not otherwise vegetated at final site sta-
bilization.Final stabilization means the completion of all soil disturbing activities at
the site and the establishment of a permanent vegetative cover,or equivalent per-
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manent 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 estab-
lished by seed before water flow;install sod in the channel bottom—over hydromulch
and erosion control blankets.
l Confirm the installation of all required surface water control measures to prevent
seed from washing away.
l Hydroseed applications shall include a minimum of 1,500 pounds per acre of
mulch with 3 percent tackifier.See BMP C121:Mulching (p.284)for specifications.
l 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.
l When installing seed via hydroseeding operations,only about 1/3 of the seed actu-
ally 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.
l 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:
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l Irrigation.
l Reapplication of mulch.
l 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).
l Seed may be installed by hand if:
l Temporary and covered by straw,mulch,or topsoil.
l Permanent in small areas (usually less than 1 acre)and covered with mulch,
topsoil,or erosion blankets.
l The seed mixes listed in the tables below include recommended mixes for
both temporary and permanent seeding.
l 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.
l Consult the local suppliers or the local conservation district for their recom-
mendations because the appropriate mix depends on a variety of factors,
including location,exposure,soil type,slope,and expected foot traffic.Altern-
ative seed mixes approved by the local authority may be used.
l Other mixes may be appropriate,depending on the soil type and hydrology of
the area.
l Table II-4.1.2 Temporary Erosion Control Seed Mix (p.280)lists the standard mix
for areas requiring a temporary vegetative cover.
%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-4.1.2 Temporary Erosion Control Seed Mix
l Table II-4.1.3 Landscaping Seed Mix (p.281)lists a recommended mix for land-
scaping seed.
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%Weight %Purity %Germination
Perennial rye blend
Lolium perenne
70 98 90
Chewings and red fescue blend
Festuca rubra var.commutata or Festuca rubra
30 98 90
Table II-4.1.3 Landscaping Seed Mix
l Table II-4.1.4 Low-Growing Turf Seed Mix (p.281)lists a turf seed mix for dry situ-
ations where there is no need for watering.This mix requires very little main-
tenance.
%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-4.1.4 Low-Growing Turf Seed Mix
l Table II-4.1.5 Bioswale Seed Mix*(p.281)lists a mix for bioswales and other inter-
mittently wet areas.
%Weight %Purity %Germination
Tall or meadow fescue
Festuca arundinacea or Festuca ela-
tior
75-80 98 90
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-4.1.5 Bioswale Seed Mix*
l Table II-4.1.6 Wet Area Seed Mix*(p.282)lists a low-growing,relatively non-invas-
ive seed mix appropriate for very wet areas that are not regulated wetlands.Apply
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this mixture at a rate of 60 pounds per acre.Consult Hydraulic Permit Authority
(HPA)for seed mixes if applicable.
%Weight %Purity %Germination
Tall or meadow fescue
Festuca arundinacea or Festuca ela-
tior
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-4.1.6 Wet Area Seed Mix*
l Table II-4.1.7 Meadow Seed Mix (p.282)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 appro-
priateness of clover,a fairly invasive species,in the mix.Amending the soil can
reduce the need for clover.
%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
Table II-4.1.7 Meadow Seed Mix
l Roughening and Rototilling:
l The seedbed should be firm and rough.Roughen all soil no matter what the
slope.Track walk slopes before seeding if engineering purposes require
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compaction.Backblading or smoothing of slopes greater than 4H:1V is not
allowed if they are to be seeded.
l Restoration-based landscape practices require deeper incorporation than
that provided by a simple single-pass rototilling treatment.Wherever prac-
tical,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.
l Fertilizers:
l Conducting soil tests to determine the exact type and quantity of fertilizer is
recommended.This will prevent the over-application of fertilizer.
l Organic matter is the most appropriate form of fertilizer because it provides
nutrients (including nitrogen,phosphorus,and potassium)in the least water-
soluble form.
l 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 fer-
tilizer to the hydromulch machine,or agitate,more than 20 minutes before
use.Too much agitation destroys the slow-release coating.
l There are numerous products available that take the place of chemical fer-
tilizers.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.
l Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix:
l 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.Numer-
ous products are available commercially.Installed products per man-
ufacturer’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.
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l BFMs and MBFMs provide good alternatives to blankets in most areas requir-
ing vegetation establishment.Advantages over blankets include:
l BFM and MBFMs do not require surface preparation.
l Helicopters can assist in installing BFM and MBFMs in remote areas.
l On slopes steeper than 2.5H:1V,blanket installers may require ropes
and harnesses for safety.
l Installing BFM and MBFMs can save at least $1,000 per acre com-
pared 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 pre-
vents adequate grass growth,this time limit may be relaxed at the discretion of the local
authority when sensitive areas would otherwise be protected.
l Reseed and protect by mulch any areas that experience erosion after achieving
adequate cover.Reseed and protect by mulch any eroded area.
l 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:Tem-
porary 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 con-
sideration 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 top-
soil 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:
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BMP C123:Plastic Covering
Purpose
Plastic covering provides immediate,short-term erosion protection to slopes and dis-
turbed 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.
l 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.
l 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.
l 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.
l To prevent undercutting,trench and backfill rolled plastic covering products.
l While plastic is inexpensive to purchase,the added cost of installation,main-
tenance,removal,and disposal make this an expensive material,up to $1.50-2.00
per square yard.
l 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.
l 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.
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Design and Installation Specifications
l 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 imme-
diately.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.
l Plastic sheeting shall have a minimum thickness of 0.06 millimeters.
l If erosion at the toe of a slope is likely,a gravel berm,riprap,or other suitable pro-
tection shall be installed at the toe of the slope in order to reduce the velocity of run-
off.
Maintenance Standards
l Torn sheets must be replaced and open seams repaired.
l Completely remove and replace the plastic if it begins to deteriorate due to ultra-
violet radiation.
l Completely remove plastic when no longer needed.
l 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
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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
l 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
l Vegetate or mulch areas that will not receive vehicle traffic.In areas where plant-
ing,mulching,or paving is impractical,apply gravel or landscaping rock.
l 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 ori-
ginal ground cover as long as practical.
l Construct natural or artificial windbreaks or windscreens.These may be designed
as enclosures for small dust sources.
l 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 (p.270).
l 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.
l Spray exposed soil areas with a dust palliative,following the manufacturer’s
instructions and cautions regarding handling and application.Used oil is pro-
hibited from use as a dust suppressant.Local governments may approve other
dust palliatives such as calcium chloride or PAM.
l PAM (BMP C126:Polyacrylamide (PAM)for Soil Erosion Protection (p.300))
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 infilt-
ration 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:
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l Lower speed limits.High vehicle speed increases the amount of dust stirred up
from unpaved roads and lots.
l Upgrade the road surface strength by improving particle size,shape,and mineral
types that make up the surface and base materials.
l 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.
l Use geotextile fabrics to increase the strength of new roads or roads undergoing
reconstruction.
l Encourage the use of alternate,paved routes,if available.
l Restrict use of paved roadways by tracked vehicles and heavy trucks to prevent
damage to road surface and base.
l 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.
l Pave unpaved permanent roads and other trafficked areas.
l Use vacuum street sweepers.
l Remove mud and other dirt promptly so it does not dry and then turn into dust.
l Limit dust-causing work on windy days.
l 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 unex-
pected 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 Con-
struction SWPPP requirements.In addition,contractors can save money by buying some
materials in bulk and storing them at their office or yard.
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Conditions of Use
l 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 fab-
ric and steel “T”posts.
l Materials are stockpiled and readily available before any site clearing,grubbing,or
earthwork begins.A large contractor or developer could keep a stockpile of mater-
ials that are available for use on several projects.
l 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
l 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.
l Re-stock materials used as needed.
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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:
l Curbs
l Sidewalks
l Roads
l Bridges
l Foundations
l Floors
l Runways
Design and Installation Specifications
l 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 (p.317)for inform-
ation on concrete washout areas.
l 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 con-
crete washout areas.
l Wash off hand tools including,but not limited to,screeds,shovels,rakes,floats,
and trowels into formed areas only.
l Wash equipment difficult to move,such as concrete pavers in areas that do not dir-
ectly drain to natural or constructed stormwater conveyances.
l Do not allow washdown from areas,such as concrete aggregate driveways,to
drain directly to natural or constructed stormwater conveyances.
l Contain washwater and leftover product in a lined container when no formed areas
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are available.Dispose of contained concrete in a manner that does not violate
ground water or surface water quality standards.
l Always use forms or solid barriers for concrete pours,such as pilings,within 15-
feet of surface waters.
l Refer to BMP C252:High pH Neutralization Using CO2 (p.409)and BMP C253:
pH Control for High pH Water (p.412)for pH adjustment requirements.
l Refer to the Construction Stormwater General Permit for pH monitoring require-
ments if the project involves one of the following activities:
l Significant concrete work (greater than 1,000 cubic yards poured concrete or
recycled concrete used over the life of a project).
l The use of engineered soils amended with (but not limited to)Portland
cement-treated base,cement kiln dust or fly ash.
l Discharging stormwater to segments of water bodies on the 303(d)list (Cat-
egory 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:
l Sawing
l Coring
l Grinding
l Roughening
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l Hydro-demolition
l Bridge and road surfacing
Design and Installation Specifications
l Vacuum slurry and cuttings during cutting and surfacing operations.
l Slurry and cuttings shall not remain on permanent concrete or asphalt pavement
overnight.
l Slurry and cuttings shall not drain to any natural or constructed drainage con-
veyance including stormwater systems.This may require temporarily blocking
catch basins.
l Dispose of collected slurry and cuttings in a manner that does not violate ground
water or surface water quality standards.
l Do not allow process water generated during hydro-demolition,surface rough-
ening or similar operations to drain to any natural or constructed drainage con-
veyance including stormwater systems.Dispose process water in a manner that
does not violate ground water or surface water quality standards.
l 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 stand-
ards could occur,stop operations and immediately implement preventive measures such
as berms,barriers,secondary containment,and vacuum trucks.
BMP C153:Material Delivery,Storage and Containment
Purpose
Prevent,reduce,or eliminate the discharge of pollutants to the stormwater system or
watercourses from material delivery and storage.Minimize the storage of hazardous
materials on-site,store materials in a designated area,and install secondary con-
tainment.
Conditions of Use
These procedures are suitable for use at all construction sites with delivery and
storage of the following materials:
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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 per-
cent),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 per-
cent),an engineered energy dissipater shall be used.
l Filter fabric or erosion control blankets should always be used under riprap to pre-
vent scour and channel erosion.
l New pipe outfalls can provide an opportunity for low-cost fish habitat improve-
ments.For example,an alcove of low-velocity water can be created by con-
structing 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 shel-
ter during high flows.Bank stabilization,bioengineering,and habitat features may
be required for disturbed areas.This work may require a HPA.See Volume V
(p.765)for more information on outfall system design.
Maintenance Standards
l Inspect and repair as needed.
l Add rock as needed to maintain the intended function.
l 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 sta-
bilization 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 run-
off 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 pre-
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vent 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 (p.358)lists several options for inlet protection.
All of the methods for storm drain inlet protection tend to plug and require a high fre-
quency of maintenance.Limit drainage areas to one acre or less.Possibly provide emer-
gency overflows with additional end-of-pipe treatment where stormwater ponding would
cause a hazard.
Type of Inlet
Protection
Emergency
Overflow
Applicable for
Paved/Earthen
Surfaces
Conditions of Use
Drop Inlet Protection
Excavated drop
inlet protection
Yes,tem-
porary flood-
ing will occur
Earthen
Applicable for heavy flows.Easy
to maintain.Large area Require-
ment: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 pro-
tection
No
Applicable for heavy concentrated
flows.Will pond.Can withstand
traffic.
Catch basin fil-
ters Yes Paved or Earthen Frequent Maintenance required.
Curb Inlet Protection
Curb inlet pro-
tection 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 Sed-
iment trap 18 month expected life.
Table II-4.2.2 Storm Drain Inlet Protection
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.
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l Provide a depth of 1-2 ft as measured from the crest of the inlet structure.
l Slope sides of excavation no steeper than 2H:1V.
l Minimum volume of excavation 35 cubic yards.
l Shape basin to fit site with longest dimension oriented toward the longest inflow
area.
l Install provisions for draining to prevent standing water problems.
l Clear the area of all debris.
l Grade the approach to the inlet uniformly.
l Drill weep holes into the side of the inlet.
l Protect weep holes with screen wire and washed aggregate.
l Seal weep holes when removing structure and stabilizing area.
l Build a temporary dike,if necessary,to the down slope side of the structure to pre-
vent bypass flow.
Block and Gravel Filter -A barrier formed around the storm drain inlet with standard con-
crete blocks and gravel.See Figure II-4.2.8 Block and Gravel Filter (p.360).
l Provide a height of 1 to 2 feet above inlet.
l Recess the first row 2-inches into the ground for stability.
l Support subsequent courses by placing a 2x4 through the block opening.
l Do not use mortar.
l Lay some blocks in the bottom row on their side for dewatering the pool.
l Place hardware cloth or comparable wire mesh with ½-inch openings over all
block openings.
l Place gravel just below the top of blocks on slopes of 2H:1V or flatter.
l An alternative design is a gravel donut.
l Provide an inlet slope of 3H:1V.
l Provide an outlet slope of 2H:1V.
l Provide a1-foot wide level stone area between the structure and the inlet.
l Use inlet slope stones 3 inches in diameter or larger.
l Use gravel ½-to ¾-inch at a minimum thickness of 1-foot for the outlet slope.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 359
Figure II-4.2.8 Block and Gravel Filter
DEP A RTMENT OF
ECOLOG Y
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.8
Block and Gravel Filter
Revised August 2015
NOT TO SCALE
Plan View
A
A
Section A-A
Drain grate
Concrete block
Gravel backfill
Less than
5% slop
e
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.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 360
Gravel and Wire Mesh Filter -A gravel barrier placed over the top of the inlet.This struc-
ture does not provide an overflow.
l Use a hardware cloth or comparable wire mesh with ½-inch openings.
l Use coarse aggregate.
l Provide a height 1-foot or more,18-inches wider than inlet on all sides.
l Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot
beyond each side of the inlet structure.
l Overlap the strips if more than one strip of mesh is necessary.
l Place coarse aggregate over the wire mesh.
l 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 require-
ments 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.
l Provides 5 cubic feet of storage.
l Requires dewatering provisions.
l Provides a high-flow bypass that will not clog under normal use at a construction
site.
l 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.
l Use wire mesh with ½-inch openings.
l Use extra strength filter cloth.
l Construct a frame.
l Attach the wire and filter fabric to the frame.
l Pile coarse washed aggregate against wire/fabric.
l 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 (p.363).
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 361
l Use wire mesh with ½-inch openings.
l Place two concrete blocks on their sides abutting the curb at either side of the inlet
opening.These are spacer blocks.
l Place a 2x4 stud through the outer holes of each spacer block to align the front
blocks.
l Place blocks on their sides across the front of the inlet and abutting the spacer
blocks.
l Place wire mesh over the outside vertical face.
l 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
(p.364).
l 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.
l Construct a horseshoe shaped sedimentation trap on the outside of the berm sized
to sediment trap standards for protecting a culvert inlet.
Maintenance Standards
l 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.
l Do not wash sediment into storm drains while cleaning.Spread all excavated
material evenly over the surrounding land area or stockpile and stabilize as appro-
priate.
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
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 362
Figure II-4.2.9 Block and Gravel Curb Inlet Protection
DEP A RTMENT OF
ECOLOG Y
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.9
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
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 363
Figure II-4.2.10 Curb and Gutter Barrier
DEP A RTMENT OF
ECOLOG Y
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.10
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.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 364
BMP C232:Gravel Filter Berm
Purpose
A gravel filter berm is constructed on rights-of-way or traffic areas within a construction
site to retain sediment by using a filter berm of gravel or crushed rock.
Conditions of Use
Where a temporary measure is needed to retain sediment from rights-of-way or in traffic
areas on construction sites.
Design and Installation Specifications
l Berm material shall be ¾to 3 inches in size,washed well-grade gravel or crushed
rock with less than 5 percent fines.
l Spacing of berms:
o Every 300 feet on slopes less than 5 percent
o Every 200 feet on slopes between 5 percent and 10 percent
o Every 100 feet on slopes greater than 10 percent
l Berm dimensions:
o 1 foot high with 3H:1V side slopes
o 8 linear feet per 1 cfs runoff based on the 10-year,24-hour design storm
Maintenance Standards
l Regular inspection is required.Sediment shall be removed and filter material
replaced as needed.
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 (p.369)for details on silt fence con-
struction.
Conditions of Use
Silt fence may be used downslope of all disturbed areas.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 367
l 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.
l Silt fence is not intended to treat concentrated flows,nor is it intended to treat sub-
stantial amounts of overland flow.Convey any concentrated flows through the
drainage system to a sediment pond.
l 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.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 368
Figure II-4.2.12 Silt Fence
DEP A RTMENT OF
ECOLOG Y
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.12
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
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 369
Design and Installation Specifications
l Use in combination with sediment basins or other BMPs.
l Maximum slope steepness (normal (perpendicular)to fence line)1H:1V.
l Maximum sheet or overland flow path length to the fence of 100 feet.
l Do not allow flows greater than 0.5 cfs.
l The geotextile used shall meet the following standards.All geotextile properties lis-
ted 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 Stand-
ards (p.370)):
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
Table II-4.2.3 Geotextile Standards
l 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.
l 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.
l One-hundred percent biodegradable silt fence is available that is strong,long last-
ing,and can be left in place after the project is completed,if permitted by local reg-
ulations.
l Refer to Figure II-4.2.12 Silt Fence (p.369)for standard silt fence details.Include
the following standard Notes for silt fence on construction plans and specifications:
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 370
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 fil-
ter fabric lengths as required.Locate all sewn seams at support posts.Altern-
atively,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 spa-
cing 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 ultra-
violet 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
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 371
be a maximum of 6-feet.Posts shall consist of either:
l 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.
l No.6 steel rebar or larger.
l ASTM A 120 steel pipe with a minimum diameter of 1-inch.
l U,T,L,or C shape steel posts with a minimum weight of 1.35 lbs./ft.
l 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.
l 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.
l 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 con-
tours.
l Refer to Figure II-4.2.13 Silt Fence Installation by Slicing Method (p.374)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 install-
ation.
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.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 372
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 fil-
ter 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.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 373
Figure II-4.2.13 Silt Fence Installation by Slicing Method
DEP A RTMENT OF
ECOLOG Y
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.13
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.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 374
Maintenance Standards
l Repair any damage immediately.
l Intercept and convey all evident concentrated flows uphill of the silt fence to a sed-
iment pond.
l 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.
l Remove sediment deposits when the deposit reaches approximately one-third the
height of the silt fence,or install a second silt fence.
l Replace filter fabric that has deteriorated due to ultraviolet breakdown.
BMP C234:Vegetated Strip
Purpose
Vegetated strips reduce 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.
Conditions of Use
l Vegetated strips may be used downslope of all disturbed areas.
l Vegetated strips are not intended to treat concentrated flows,nor are they intended
to treat substantial amounts of overland flow.Any concentrated flows must be con-
veyed through the drainage system to a sediment pond.The only circumstance in
which overland flow can be treated solely by a strip,rather than by a sediment
pond,is when the following criteria are met (see Table II-4.2.4 Contributing Drain-
age Area for Vegetated Strips (p.375)):
Average Contributing
Area Slope
Average Contributing Area
Percent Slope
Max Contributing area
Flowpath Length
1.5H :1V or flatter 67%or flatter 100 feet
2H :1V or flatter 50%or flatter 115 feet
4H :1V or flatter 25%or flatter 150 feet
6H :1V or flatter 16.7%or flatter 200 feet
10H :1V or flatter 10%or flatter 250 feet
Table II-4.2.4 Contributing Drainage Area for Vegetated Strips
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 375
Design and Installation Specifications
l The vegetated strip shall consist of a minimum of a 25-foot flowpath length con-
tinuous strip of dense vegetation with topsoil.Grass-covered,landscaped areas
are generally not adequate because the volume of sediment overwhelms the
grass.Ideally,vegetated strips shall consist of undisturbed native growth with a
well-developed soil that allows for infiltration of runoff.
l The slope within the strip shall not exceed 4H:1V.
l The uphill boundary of the vegetated strip shall be delineated with clearing limits.
Maintenance Standards
l Any areas damaged by erosion or construction activity shall be seeded imme-
diately and protected by mulch.
l If more than 5 feet of the original vegetated strip width has had vegetation removed
or is being eroded,sod must be installed.
l If there are indications that concentrated flows are traveling across the buffer,sur-
face water controls must be installed to reduce the flows entering the buffer,or addi-
tional perimeter protection must be installed.
BMP C235:Wattles
Purpose
Wattles are temporary erosion and sediment control barriers consisting of straw,com-
post,or other material that is wrapped in biodegradable tubular plastic or similar encas-
ing material.They reduce the velocity and can spread the flow of rill and sheet runoff,
and can capture and retain sediment.Wattles are typically 8 to 10 inches in diameter
and 25 to 30 feet in length.Wattles are placed in shallow trenches and staked along the
contour of disturbed or newly constructed slopes.See Figure II-4.2.14 Wattles (p.378)for
typical construction details.WSDOT Standard Plan I-30.30-00 also provides information
on Wattles (http://www.wsdot.wa.gov/Design/Standards/Plans.htm#SectionI)
Conditions of Use
l Use wattles:
l In disturbed areas that require immediate erosion protection.
l On exposed soils during the period of short construction delays,or over
winter months.
l On slopes requiring stabilization until permanent vegetation can be estab-
lished.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 376
l The material used dictates the effectiveness period of the wattle.Generally,
Wattles are typically effective for one to two seasons.
l Prevent rilling beneath wattles by properly entrenching and abutting wattles
together to prevent water from passing between them.
Design Criteria
l Install wattles perpendicular to the flow direction and parallel to the slope contour.
l Narrow trenches should be dug across the slope on contour to a depth of 3-to 5-
inches on clay soils and soils with gradual slopes.On loose soils,steep slopes,
and areas with high rainfall,the trenches should be dug to a depth of 5-to 7-
inches,or 1/2 to 2/3 of the thickness of the wattle.
l Start building trenches and installing wattles from the base of the slope and work
up.Spread excavated material evenly along the uphill slope and compacted using
hand tamping or other methods.
l Construct trenches at intervals of 10-to 25-feet depending on the steepness of the
slope,soil type,and rainfall.The steeper the slope the closer together the
trenches.
l Install the wattles snugly into the trenches and abut tightly end to end.Do not over-
lap the ends.
l Install stakes at each end of the wattle,and at 4-foot centers along entire length of
wattle.
l If required,install pilot holes for the stakes using a straight bar to drive holes
through the wattle and into the soil.
l Wooden stakes should be approximately 3/4 x 3/4 x 24 inches min.Willow cuttings
or 3/8-inch rebar can also be used for stakes.
l Stakes should be driven through the middle of the wattle,leaving 2 to 3 inches of
the stake protruding above the wattle.
Maintenance Standards
l Wattles may require maintenance to ensure they are in contact with soil and thor-
oughly entrenched,especially after significant rainfall on steep sandy soils.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 377
Figure II-4.2.14 Wattles
DEP A RTMENT OF
ECOLOG Y
State of Washington
Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions,
limitation of liability, and disclaimer.
Figure II-4.2.14
Wattles
Revised November 2015
NOT TO SCALE
3' - 4'
(1.2m)
Adjacent rolls
shall tightly abut
Straw rolls must be
placed along slope
contours
Spacing depends
on soil type and
slope steepness
10' - 25' (3-8m)
Sediment, organic matter,
and native seeds are
captured behind the rolls.
Live Stake
1" x 1" Stake
(25 x 25mm)
3" - 5" (75-125mm)
8" - 10" Dia.
(200-250mm)
NOTE:
1.Straw roll installation requires the placement and secure staking
of the roll in a trench, 3" - 5" (75-125mm) deep, dug on contour.
Runoff must not be allowed to run under or around roll.
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 378
l Inspect the slope after significant storms and repair any areas where wattles are
not tightly abutted or water has scoured beneath the wattles.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C235:Wattles.
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 C236:Vegetative Filtration
Purpose
Vegetative Filtration may be used in conjunction with BMP C241:Temporary Sediment
Pond (p.388),BMP C206:Level Spreader (p.348)and a pumping system with surface
intake to improve turbidity levels of stormwater discharges by filtering through existing
vegetation where undisturbed forest floor duff layer or established lawn with thatch layer
are present.Vegetative Filtration can also be used to infiltrate dewatering waste from
foundations,vaults,and trenches as long as runoff does not occur.
Conditions of Use
l For every five acre of disturbed soil use one acre of grass field,farm pasture,or
wooded area.Reduce or increase this area depending on project size,ground
water table height,and other site conditions.
l Wetlands shall not be used for filtration.
l Do not use this BMP in areas with a high ground water table,or in areas that will
have a high seasonal ground water table during the use of this BMP.
l This BMP may be less effective on soils that prevent the infiltration of the water,
such as hard till.
l Using other effective source control measures throughout a construction site will
prevent the generation of additional highly turbid water and may reduce the time
period or area need for this BMP.
l Stop distributing water into the vegetated area if standing water or erosion results.
Design Criteria
l Find land adjacent to the project that has a vegetated field,preferably a farm field,
or wooded area.
l If the project site does not contain enough vegetated field area consider obtaining
2014 Stormwater Management Manual for Western Washington
Volume II -Chapter 4 -Page 379
Stormwater Pollution Prevention Plan
27
Appendix C – Alternative BMPs
The following includes a list of possible alternative BMPs for each of the 12 elements not
described in the main SWPPP text. This list can be referenced in the event a BMP for a specific
element is not functioning as designed and an alternative BMP needs to be implemented.
Element #1 - Mark Clearing Limits
Element #2 - Establish Construction Access
Element #3 - Control Flow Rates
Element #4 - Install Sediment Controls
Straw Bale Barrier (BMP C230)
Straw Wattles (BMP C235)
Storm Drain Inlet Protection (BMP C220)
Advanced BMPs:
Element #5 - Stabilize Soils
Preserving Natural Vegetation (BMP C101)
Element #6 - Protect Slopes
Element #8 - Stabilize Channels and Outlets
Channel Lining (BMP C202)
Straw Wattles (BMP C235)
Interceptor Dike and Swale (BMP C200)
Element #10 - Control Dewatering
Check Dams (BMP C207)
Outlet Protection (BMP C209)
Additional Advanced BMPs to Control Dewatering:
Stormwater Pollution Prevention Plan
29
Appendix D – General Permit
Stormwater Pollution Prevention Plan
30
Appendix E – Site Inspection Forms (and Site Log)
The results of each inspection shall be summarized in an inspection report or checklist
that is entered into or attached to the site log book. It is suggested that the inspection
report or checklist be included in this appendix to keep monitoring and inspection
information in one document, but this is optional. However, it is mandatory that this
SWPPP and the site inspection forms be kept onsite at all times during construction, and
that inspections be performed and documented as outlined below.
At a minimum, each inspection report or checklist shall include:
a. Inspection date/times
b. Weather information: general conditions during inspection,
approximate amount of precipitation since the last inspection,
and approximate amount of precipitation within the last 24 hours.
c. A summary or list of all BMPs that have been implemented,
including observations of all erosion/sediment control structures or
practices.
d. The following shall be noted:
i. locations of BMPs inspected,
ii. locations of BMPs that need maintenance,
iii. the reason maintenance is needed,
iv. locations of BMPs that failed to operate as designed or
intended, and
v. locations where additional or different BMPs are needed, and
the reason(s) why
e. A description of stormwater discharged from the site. The presence
of suspended sediment, turbid water, discoloration, and/or oil
sheen shall be noted, as applicable.
f. A description of any water quality monitoring performed during
inspection, and the results of that monitoring.
g. General comments and notes, including a brief description of any
BMP repairs, maintenance or installations made as a result of the
inspection.
h. A statement that, in the judgment of the person conducting the site
inspection, the site is either in compliance or out of compliance
with the terms and conditions of the SWPPP and the NPDES
permit. If the site inspection indicates that the site is out of
compliance, the inspection report shall include a summary of the
Stormwater Pollution Prevention Plan
31
remedial actions required to bring the site back into compliance, as
well as a schedule of implementation.
i. Name, title, and signature of person conducting the site inspection;
and the following statement: “I certify under penalty of law that
this report is true, accurate, and complete, to the best of my
knowledge and belief”.
When the site inspection indicates that the site is not in compliance with any terms and
conditions of the NPDES permit, the Permittee shall take immediate action(s) to: stop,
contain, and clean up the unauthorized discharges, or otherwise stop the noncompliance;
correct the problem(s); implement appropriate Best Management Practices (BMPs),
and/or conduct maintenance of existing BMPs; and achieve compliance with all
applicable standards and permit conditions. In addition, if the noncompliance causes a
threat to human health or the environment, the Permittee shall comply with the
Noncompliance Notification requirements in Special Condition S5.F of the permit.
Stormwater Pollution Prevention Plan
32
Site Inspection Form
General Information
Project Name:
Inspector Name: Title:
CESCL # :
Date: Time:
Inspection Type: □ After a rain event
□ Weekly
□ Turbidity/transparency benchmark exceedance
□ Other
Weather
Precipitation Since last inspection In last 24 hours
Description of General Site Conditions:
Inspection of BMPs
Element 1: Mark Clearing Limits
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Element 2: Establish Construction Access
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Stormwater Pollution Prevention Plan
33
Element 3: Control Flow Rates
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Element 4: Install Sediment Controls
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Stormwater Pollution Prevention Plan
34
Element 5: Stabilize Soils
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Element 6: Protect Slopes
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Stormwater Pollution Prevention Plan
35
Element 7: Protect Drain Inlets
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Element 8: Stabilize Channels and Outlets
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Stormwater Pollution Prevention Plan
36
Element 9: Control Pollutants
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Element 10: Control Dewatering
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
BMP:
Location Inspected Functioning Problem/Corrective Action Y N Y N NIP
Stormwater Pollution Prevention Plan
37
Stormwater Discharges From the Site
Observed? Problem/Corrective Action Y N
Location
Turbidity
Discoloration
Sheen
Location
Turbidity
Discoloration
Sheen
Stormwater Pollution Prevention Plan
38
Water Quality Monitoring
Was any water quality monitoring conducted? □ Yes □ No
If water quality monitoring was conducted, record results here:
If water quality monitoring indicated turbidity 250 NTU or greater; or transparency 6
cm or less, was Ecology notified by phone within 24 hrs?
□ Yes □ No
If Ecology was notified, indicate the date, time, contact name and phone number
below:
Date:
Time:
Contact Name:
Phone #:
General Comments and Notes
Include BMP repairs, maintenance, or installations made as a result of the inspection.
Were Photos Taken? □ Yes □ No
If photos taken, describe photos below:
Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200••Section I: Project Information•••Section II: Bond Quantities Worksheets••Section II.a EROSION CONTROL (Stabilization/Erosion Sediment Control (ESC))•Section II.b TRANSPORTATION (Street and Site Improvements)•Section II.c DRAINAGE (Drainage and Stormwater Facilities): •Section II.d WATER - ONLY APPLICABLE IF WATER SERVICE IS PROVIDED BY CITY OF RENTON•Section II.e SANITARY SEWER - ONLY APPLICABLE IF SEWER SERVICE IS PROVIDED BY CITY OF RENTON••••••Section III. Bond Worksheet• This section calculates the required Permit Bond for construction permit issuance as well as the required Maintenance Bond for project close-out submittals to release the permit bond on a project. All unit prices include labor, equipment, materials, overhead and profit. Complete the 'Quantity' columns for each of the appropriate section(s). Include existing Right-of-Way (ROW), Future Public Improvements and Private Improvements.The 'Quantity Remaining' column is only to be used when a project is under construction. The City allows one (1) bond reduction during the life of the project with the exception of the maintenance period reduction.Excel will auto-calculate and auto-populate the relevant fields and subtotals throughout the document. Only the 'Quantity' columns should need completing.Additional items not included in the lists can be added under the "write-in" sections. Provide a complete description, cost estimate and unit of measure for each write-in item. Note: Private improvements, with the exception of stormwater facilities, are not included in the bond amount calculation, but must be entered on the form. Stormwater facilities (public and private) are required to be included in the bond amount.BOND QUANTITY WORKSHEET INSTRUCTIONSThis worksheet is intended to be a "working" copy of the bond quantity worksheet, which will be used throughout all phases of the project, from initial submittal to project close-out approval. Submit this workbook, in its entirety, as follows:The following forms are to be completed by the engineer/developer/applicant as applicable to the project: The Bond Worksheet form will auto-calculate and auto-populate from the information provided in Section I and Section II.This section includes all pertinent information for the projectSection II contains a separate spreadsheet TAB for each of the following specialties: (1) electronic copy (.xlsx format) and (1) hard copy of the entire workbook for civil construction permit submittal. Hard copies are to be included as part of the Technical Information Report (TIR).(1) electronic copy (.xlsx format) and (1) hard copy of the entire workbook for final close-out submittal.This section must be completed in its entiretyInformation from this section auto-populates to all other relevant areas of the workbookPage 1 of 14Ref 8-H Bond Quantity WorksheetINSTRUCTIONSUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021
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: SITE IMPROVEMENT BOND QUANTITY WORKSHEETPROJECT INFORMATIONCITY OF RENTONCITY OF RENTON1 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 SubmittalEngineer Stamp Required (all cost estimates must have original wet stamp and signature)Clearing and GradingUtility ProvidersN/AProject Location and DescriptionProject Owner InformationSouthport Park Avenue ExtensionRenton, WA, 98056082305-9178SECO Development##-######425-282-58333/31/2021Prepared by:FOR APPROVALProject Phase 1timb@cplinc.comTim Brockway33708Coughlin Porter Lundeen801 2nd Ave, Suite 900, Seattle, WA 98104206-343-0460Site Address1083 Lake Washington Blvd N, Suite 50Street Intersection########Abbreviated Legal Description:LOT A OF CITY OF RENTON LOT LINE ADJUSTMENT NO LUA 98-176-LLA RECORDING NO 9902019014 BEING A PORTION OF GOV LOT 1 IN NW 1/4 OF SECTION 08-23-05 & PORTION LAKE WASH SHORELAND LY NLY & WLY OF BURLINGTON NORTHERN RAILROAD CO R/W TCO 17-1681Page 2 of 14Ref 8-H Bond Quantity WorksheetSECTION I PROJECT INFORMATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021
CED Permit #:########UnitReference #PriceUnitQuantity CostBackfill & compaction-embankmentESC-16.50$ CY577537,537.50Check dams, 4" minus rockESC-2SWDM 5.4.6.380.00$ Each Catch Basin ProtectionESC-335.50$ Each7248.50Crushed surfacing 1 1/4" minusESC-4WSDOT 9-03.9(3)95.00$ CY DitchingESC-59.00$ CY Excavation-bulkESC-62.00$ CY4.59.00Fence, siltESC-7SWDM 5.4.3.11.50$ LF475712.50Fence, 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$ LF Jute 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$ SY3301,320.00Rip 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$ Each Sediment 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$ HR606,600.00Water truck, dust controlESC-31SWDM 5.4.7140.00$ HR UnitReference #PriceUnitQuantity Cost EROSION/SEDIMENT SUBTOTAL:46,427.50SALES TAX @ 10%4,642.75EROSION/SEDIMENT TOTAL:51,070.25(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 3/31/2021
CED Permit #:########ExistingFuture 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$ AcreExcavation - 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$ LF80016,000.00Fencing, chain link, gate, vinyl coated, 20' GI-121,400.00$ Each11,400.00Fill & compact - common barrowGI-1325.00$ CY4208105,200.00Fill & 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$ SY23004,600.00Monuments, 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:127,200.00(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 3/31/2021
CED Permit #:########ExistingFuture 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$ SY82929,015.00Barricade, Type III ( Permanent )RI-556.00$ LFGuard RailRI-630.00$ LFCurb & Gutter, rolledRI-717.00$ LFCurb & Gutter, verticalRI-812.50$ LF150018,750.00Curb and Gutter, demolition and disposalRI-918.00$ LFCurb, extruded asphaltRI-105.50$ LFCurb, extruded concreteRI-117.00$ LFSawcut, asphalt, 3" depthRI-121.85$ LF130240.50Sawcut, concrete, per 1" depthRI-133.00$ LFSealant, asphaltRI-142.00$ LFShoulder, gravel, 4" thickRI-1515.00$ SYSidewalk, 4" thickRI-1638.00$ SY45017,100.00Sidewalk, 4" thick, demolition and disposalRI-1732.00$ SYSidewalk, 5" thickRI-1841.00$ SYSidewalk, 5" thick, demolition and disposalRI-1940.00$ SYSign, Handicap RI-2085.00$ EachStriping, per stallRI-217.00$ EachStriping, thermoplastic, ( for crosswalk )RI-223.00$ SF175525.00Striping, 4" reflectorized lineRI-230.50$ LF1500750.00Additional 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$ SY2300103,500.00HMA 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:169,880.50(B)(C)(D)(E)Page 5 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021
CED Permit #:########ExistingFuture 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$ SY2" 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:(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-11,500.00$ LS11,500.00Street Light System ( # of Poles)TR-295,000.00$ LS195,000.00Traffic SignalTR-3Traffic Signal ModificationTR-4SUBTOTAL TRAFFIC & LIGHTING:96,500.00(B)(C)(D)(E)WRITE-IN-ITEMSSUBTOTAL WRITE-IN ITEMS:STREET AND SITE IMPROVEMENTS SUBTOTAL:393,580.50SALES TAX @ 10%39,358.05STREET AND SITE IMPROVEMENTS TOTAL:432,938.55(B)(C)(D)(E)Page 6 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021
CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostDRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/DD-126.00$ SY* (CBs include frame and lid)BeehiveD-290.00$ EachThrough-curb Inlet FrameworkD-3400.00$ EachCB Type ID-41,500.00$ Each1218,000.00CB Type ILD-51,750.00$ Each47,000.00CB Type II, 48" diameterD-62,300.00$ Each for additional depth over 4' D-7480.00$ FTCB Type II, 54" diameterD-82,500.00$ Each for additional depth over 4'D-9495.00$ FTCB Type II, 60" diameterD-102,800.00$ Each for additional depth over 4'D-11600.00$ FTCB Type II, 72" diameterD-126,000.00$ Each for additional depth over 4'D-13850.00$ FTCB Type II, 96" diameterD-1414,000.00$ Each for additional depth over 4'D-15925.00$ FTTrash Rack, 12"D-16350.00$ EachTrash Rack, 15"D-17410.00$ EachTrash Rack, 18"D-18480.00$ EachTrash Rack, 21"D-19550.00$ EachCleanout, PVC, 4"D-20150.00$ EachCleanout, PVC, 6"D-21170.00$ EachCleanout, 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$ LF2154,945.00Culvert, PVC, 15" D-2735.00$ LFCulvert, PVC, 18" D-2841.00$ LFCulvert, PVC, 24"D-2956.00$ LFCulvert, PVC, 30" D-3078.00$ LFCulvert, PVC, 36" D-31130.00$ LFCulvert, CMP, 8"D-3219.00$ LFCulvert, CMP, 12"D-3329.00$ LFSUBTOTAL THIS PAGE:29,945.00(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)Page 7 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021
CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)DRAINAGE (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 3/31/2021
CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)DRAINAGE (Continued)Culvert, LCPE, 60"D-69180.00$ LFCulvert, LCPE, 72"D-70192.00$ LFCulvert, HDPE, 6"D-7142.00$ LFCulvert, HDPE, 8"D-7242.00$ LFCulvert, HDPE, 12"D-7374.00$ LFCulvert, HDPE, 15"D-74106.00$ LFCulvert, HDPE, 18"D-75138.00$ LFCulvert, HDPE, 24"D-76221.00$ LFCulvert, HDPE, 30"D-77276.00$ LFCulvert, HDPE, 36"D-78331.00$ LFCulvert, HDPE, 48"D-79386.00$ LFCulvert, HDPE, 54"D-80441.00$ LFCulvert, HDPE, 60"D-81496.00$ LFCulvert, HDPE, 72"D-82551.00$ LFPipe, Polypropylene, 6"D-8384.00$ LFPipe, Polypropylene, 8"D-8489.00$ LFPipe, Polypropylene, 12"D-8595.00$ LFPipe, Polypropylene, 15"D-86100.00$ LFPipe, Polypropylene, 18"D-87106.00$ LFPipe, Polypropylene, 24"D-88111.00$ LFPipe, Polypropylene, 30"D-89119.00$ LFPipe, Polypropylene, 36"D-90154.00$ LFPipe, Polypropylene, 48"D-91226.00$ LFPipe, Polypropylene, 54"D-92332.00$ LFPipe, Polypropylene, 60"D-93439.00$ LFPipe, Polypropylene, 72"D-94545.00$ LFCulvert, DI, 6"D-9561.00$ LFCulvert, DI, 8"D-9684.00$ LF14512,180.00Culvert, DI, 12"D-97106.00$ LF49252,152.00Culvert, DI, 15"D-98129.00$ LFCulvert, DI, 18"D-99152.00$ LF9013,680.00Culvert, 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:78,012.00(B)(C)(D)(E)Page 9 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021
CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)Specialty 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-1512,000.00$ Each 224,000.00Bioretention FacilitySF-16Each SUBTOTAL STORMWATER FACILITIES:24,000.00(B)(C)(D)(E)Page 10 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021
CED Permit #:########ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)WRITE-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:131,957.00SALES TAX @ 10%13,195.70DRAINAGE AND STORMWATER FACILITIES TOTAL:145,152.70(B) (C) (D) (E)Page 11 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021
CED Permit #:########ExistingFuture 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 3/31/2021
CED Permit #:########ExistingFuture 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 3/31/2021
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)145,152.70$ (e)(f)Site RestorationCivil Construction PermitMaintenance Bond29,030.54$ Bond Reduction2Construction Permit Bond Amount 3Minimum Bond Amount is $10,000.001 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering.2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% willcover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering.* Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton.** Note: All prices include labor, equipment, materials, overhead and profit. 206-343-0460timb@cplinc.comSouthport Park Avenue Extension##-######Site Address082305-9178FOR APPROVAL########801 2nd Ave, Suite 900, Seattle, WA 98104196,222.95$ P (a) x 100%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS3/31/2021Tim Brockway33708Coughlin 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)EST1((b) + (c) + (d)) x 20%-$ MAINTENANCE BOND */**(after final acceptance of construction)51,070.25$ -$ 145,152.70$ 51,070.25$ -$ 145,152.70$ -$ Page 14 of 14Ref 8-H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 3/31/2021