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Technical Information Report
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Saddlebrook Div. II
13422 156"'Avenue SE, Renton,Washington
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DRS Project No. 13030
City of Renton File No. LUA 13-XXX
OwneNApplrcant
ACH Homes, LLC ':
9675 SE 36`h Street, Suite 105 �
Mercer Island, Washington 98040 i
Report Prepared by �
/ �
D. R. STRONG Consulting Engineers, Inc.
620 7t''Avenue
Kirkland WA 98033 ;
(425) 827-3063 '
Report Issue Date �
August 8, 2013
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Technical Information Report
(TIR)
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Saddlebrook Div. II
13422 156`"Avenue SE, Renton,Washington
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DRS Project No. 13030
City of Renton File No. LUA 13-XXX
OwneNApplicant
ACH Homes, LLC
9675 SE 36�h Street, Suite 105
Mercer Island, Washington 98040
Report Prepared by
� �
D. R. STRONG Consulting Engineers, Inc.
620 7th Avenue
Kirkland WA 98033
� _
(425) 827-3063
Report Issue Date
August 8, 2013
RE�E� � ��r.
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�02013 D. R.STRONG Consulting Engineers Inc. ';��FR �
I
I- TECHNICAL INFORMATION REPORT
- Saddlebrook Div. II
TABLE OF CONTENTS
SECTIONI.................................................................................................................................................... 1 II
PROJECTOVERVIEW: ........................................................................................................................... 1
PREDEVELOPED SITE CONDITIONS:................................................................................................... 1 I
DEVELOPED SITE CONDITIONS: .......................................................................................................... 1
NATURAL DRAINAGE SYSTEM FUNCTIONS:....................................................................................... 2
FIGURE 1. T!R WORKSHEET........................................................................................................... 3
FlGURE 2. VICINITY MAP..............................................................................................:................... 6
FIGURE 3. DRAlNAGE BASINS, SUBBASINS, AND SlTE CHARACTERISTICS............................ 7
F/GURE 4. SOILS............................................................................................................................... 8
SECTIONII................................................................................................................................................. 10
CONDITIONS AND REQUIREMENTS SUMMARY............................................................................... 10
SECTIONIII................................................................................................................................................ 12
OFF-SITE ANALYSIS............................................................................................................................. 12
SECTIONIV............................................................................................................................................... 13
FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN.................................. 13
EXISTING SITE HYDROLOGY(PARTA}............................................................................................... 13
FIGURE 5. PREDEVELOPMENT AREA MAP.................................................................................. 94
DEVELOPED SITE HYDROLOGY(PART B)......................................................................................... 15
BYPASS AREA HYDROLOGY............................................................................................................... 17
FIGURE 6. POST DEVELOPMENT ARE,4 MAP.............................................................................. 18
PERFORMANCE STANDARDS(PART C)............................................................................................ 19
FLOW CONTROL SYSTEM(PART D) .................................................................................................. 19
FLOW CONTROL BMP SELECTION .................................................................................................... 19
FLOW CONTROL SYSTEM................................................................................................................... 20
WATER QUALITYTREATMENT(PART E).................................................:......................................... 28
FIGURE 7. DETENTION FAClLlTY DETAILS AND BAYFILTER SIZlNG........................................ 29
SECTIONV................................................................................................................................................ 30
CONVEYANCE SYSTEM ANALYSIS AND DESIGN ............................................................................. 30
DEVELOPED 15-MINUTE TIME SERIES.............................................................................................. 30
BACKWATERANALYSIS...................................................................................................................... 32
BACKWATER ANALYSIS MAP.............................................................................................................. 34
BACKWATER ANALYSIS RESULTS..................................................................................................... 35
SECTIONVI ............................................................................................................................................... 39
SPECIAL REPORTS AND STUDIES..................................................................................................... 39
SECTIONVII ..............................................................................................................................................40
OTHER PERMITS,VARIANCES AND ADJUSTMENTS ....................................................................... 40
SECTIONVIII ............................................................................................................................................. 41
ESC PLAN ANALYSIS AND DESIGN (PART A) .................................................................:.................. 41
SWPPS PLAN DESIGN(PART B} ......................................................................................................... 41
SECTIONIX...............................................................................................................................................43
BOND QUANTITIES, FACILITY SUMMARIES,AND DECLARATION OF COVENANT........................ 43
STORMWATER FACILITYSUMMARYSHEET..................................................................................... 44
SECTIONX ................................................................................................................................................46
�2013 D. R. STRONG Consulting Engineers Inc. Saddlebrook Div. II
Technical Information Report Renton,Washington
OPERATIONS AND MAINTENANCE MANUAL..................................................................................... 46
APPENDICES.............................................................................................................................................47
APPENDIX�,A„ LEGAL DESCRIPTION................................................................................................. 48
APPENDIX"B„ BOND QUANTITY WORKSHEET................................................................................ 49
APPENDIX"C" OPERATIONS AND MAINTENACE MANUAL ............................................................. 50
APPENDIX«p„ CSWPPP...................................................................................................................... 51
O 2013 D. R.STRONG Consulting Engineers Inc. Saddlebrook Div. II
Technical Information Report Renton,Washington
SECTION I
PROJECT OVERVIEW:
The Site is located at 13422 1�6th Avenue SE in Rent�n, Was►�ingtoi�, also known as
King County Tax Parcel Number 366450-0250. The Project is the subdivision of this
existing parcel zoned R4 (0.89 ac. total) into three single-family residential lots, per the
City of Renton's (City) short plat process. The Site will utilize the detention facility within
Saddlebrook Div. I to meet flow control requirements. The pond will be redesigned to
Level Three Flow Control Standards. The Project will meet the drainage requirements
of the 2009 King County Surface Water Design Manual (Manual), as adopted by the
City.
PREDEVELOPED SITE CONDITIONS:
Total existing Site area is approximately 38,715 s.f. (0.89 ac). Total proposed Project
area is 41,095 s.f. (0.94 ac) which includes 2,380 s.f. (0.05 ac) for the right-of-way ,
frontage improvements on 156th Avenue SE. The Parcel is currently developed with a i,
single-family home, covered patio and a gravel driveway. The remainder of the Site is ,
lawn, landscaping, and scattered trees.
The 0.89 acre parcel contains a single natural discharge point near the southwest �
corner of the Site. The Site sheet flows towards the southwest corner of the Site and
into the right-of-way. From there, it is collected into the conveyance system within 156t" '
Avenue and is conveyed south.
For the purpose of hydrologic calculations, the entire Site is modeled as till forest.
DEVELOPED SITE CONDITIONS:
The applicant has gained approval to subdivide 0.89 acres into three single-family
residential lots (Project), with lot sizes ranging from approximately 10,169 to 10,983 s.f.
All existing improvements will be demolished or removed during plat construction. The
proposed impervious surface area will include a new shared driveway tract with 16 feet
of pavement. Impervious surface are will also include offsite half-street improvements
along 156th Avenue SE. The proposed shared driveway improvements total
approximately 4,411 s.f. The three single-family residences and their driveways
combined will create approximately 10,875 s.f. of impervious area (reduced from
maximum allowable, see next paragraph for details). Post-developed impervious areas
including driveways, roofs, and site frontage improvements total approximately 17,666
s.f. (includes Bypass area). The remainder of the Project will be modeled as till grass
totaling approximately 23,429 s.f. (See Section IV)
Per the 2009 King County Surface Water Design Manual (Manual}, Appendix C, each
lot within a new subdivision is required to mitigate for impervious surface area equal to
10% of the lot area. Per Figure C.1.3.A, Flow Control BMP Flowchart, the Project will
utilize Basic Dispersion with the use of splash blocks. Two splash blocks mitigating a
total of 1,400 s.f. of impervious area, will be installed with each residence. This shall
mitigate for 12.75% to 13.77% of impervious area for each lot. Also, each lot will be
restricted to an area less than 4,000 s.f. (see table below). Additionally, use of Basic
�2013 D. R.STRONG Consulting Engineers Inc. 1 Saddlebrook Div. II
Technical Information Report Renton,Washington
Dispersion allows for a 50% flow control BMP sizing credit which was used in detention
facility calculations. See table below for lot area, restricted impervious area per lot, and
percent impervious mitigated per lot.
ROOF AREA ROUTED TO RESTRICTED IMPERVIOUS TOTAL AREA PERCENT IMPERVIOUS
LOT N0. LOTAREA(S.F.) SPLASH BLOCK(S.F.) AREA PER LOT MITIGATED MITIGATED
1 10169 1400 3505 1895 18.64
2 10983 1400 3485 1915 17.44
3 10877 1400 3885 1515 13.93
All surface water runoff from impervious surfaces will be collected and conveyed to a
storm detention pond located within Tract "A of Saddlebrook Div. I. From there, runoff
will be conveyed through a BayFilter vault before entering the existing conveyance
system within 156'h Avenue SE.
NATURAL DRAINAGE SYSTEM FUNCTIONS:
A review of the SCS soils map for the area (see Figure 4, Soils) indicates Alderwood
gravelly sandy loam with 6 to 15 percent slopes (AgC). Per the Manual, this soil type is
classified as "Till" material. The SCS Soil series descriptions follow Figure 4.
In evaluating the upstream area, we reviewed the existing offsite analysis and King
County IMAP aerial topography and imagery and conducted field reconnaissance and
have concluded that upstream tributary area for the Site is negligible.
��2013 D. R. STRONG Consulting Engineers Ina 2 Saddlebrook Div. II
Technical Information Report Renton,Washington
l
FIGURE 1. TIR WORKSHEET 'I
King County Department of Development and Environmental Services I�'
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET I
Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND
PROJECT ENGINEER DESCRIPTION
Project Owner: Project Name:
ACH Homes, LLC Saddlebrook Div. II
Address/Phone: Location: '
9675 SE 36th Street, Suite 105 Township: 23 North '
Mercer Island, Washington 98040 Range: 05 East
(206) 588-1147 Section: 14
Project Engineer:
Maher A. Joudi, P.E.
D. R. STRONG Consulting Engineers
Inc.
Address/Phone:
620 7th Avenue
Kirkland WA 98033
(425) 827-3063
Part 3 TYPE OF PERMIT Part 4 OTHER REVIEWS AND PERMITS
APPLICATION
❑ Subdivision ❑ DFW HPA ❑ Shoreline
� Short Subdivision Management
� Clearing and Grading ❑ COE 404 ❑ Rockery
❑ Commercial ❑ DOE Dam Safety ❑ Structural Vault
❑ Other: ❑ FEMA Floodplain ❑ Other:
❑ COE Wetlands
Part 5 SITE COMMUNITY AND DRAINAGE BASIN
Community:
Newcastle
Drainage Basin
Lower Cedar River
�<�2013 D.R.STRONG Consulting Engineers Inc. 3 Saddlebrook Div. II
Technical Information Report Renton,Washington
Part 6 SITE CHARACTERISTICS
❑River: ❑ Floodplain
❑ Wetlands
❑ Stream: ❑ Seeps/Springs
❑ Critical Stream Reach ❑ High Groundwater Table
❑ Depressions/Swales ❑ Groundwater Recharge
❑ Lake: ❑ Other:
❑ Stee Slo es
Part 7 SOILS
Soil Type: Slopes: Erosion Potential: Erosive Velocities:
Alderwood 6-15% Moderate Slow to Medium
(AgC)
� Additional Sheets Attached: SCS Map and Soil Description, Figure 4
Part 8 DEVELOPMENT LIMITATIONS
REFERENCE LIMITATION/SITE CONSTRAINT
� Level 1 Downstream Analysis None
� Geotechnical Engineering Study
❑ Environmentally Sensiti�e Areas
❑ Level 2 Off-Site Stormwater Analysis
� Level I Traffic Impact Analysis
❑ Structural Report
❑ Additional Sheets Attached
Part 9 ESC REQUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION AFTER CONSTRUCTION
� Sedimentation Facilities � Stabilize Exposed Surface
� Stabilized Construction � Remove and Restore Temporary ESC
Entrance Facilities
� Perimeter Runoff Control � Clean and Remove All Silt and Debris
� Clearing and Grading � Ensure Operation of Permanent Facilities
Restrictions ❑ Flag Limits of SAO and open space
� Cover Practices preservation areas
� Construction Sequence ❑ Other
❑ Other
O 2013 D. R.STRONG Consulting Engineers Inc. 4 Saddlebrook Div. II
Technical Information Report Renton,Washington
Part 10 SURFACE WATER SYSTEM
❑ Grass Lined ❑ Tank ❑ Infiltration Method of Analysis:
Channel ❑ Vault ❑ Depression KCRTS
� Pipe System ❑ Energy Dissipater ❑ Flow Dispersal Compensation/
❑ Open Channel ❑ Wetland ❑ Waiver Mitigation of Eliminated
� Dry Pond ❑ Stream ❑ Regional Site Storage
❑ Wet Pond Detention N/A
Brief Description of System Operation: Runoff from impervious surFaces will be collected
and conveyed to the detention pond in Tract A of Saddlebrook Div. I. From there it will
be dischar ed to the existin conve ance s stem within 156th Avenue SE.
J 9 Y Y
� Facility Related Site Limitations:
Reference Facility Limitation
Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS
❑ Cast in Place Vault � Drainage Easement
❑ Retaining Wall � Access Easement
❑ Rockery > 4' High ❑ Native Growth Protection Easement
❑ Structural on Steep Slope � Tracts
❑ Other: ❑ Other:
Part 13 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 attachments. To the best '�
of my knowledge the information provided here is accurate.
Si ned/Date
�s 2013 D. R.STRONG Consulting Engineers Inc. 5 Saddlebrook Div. II
Technical Information Report Renton,Washington
FIGURE 2. VICINITY MAP
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The information included on this map has been compiled by King County staff from a variety of sources and is subject to change
without notice. King County makes no representations or warranties,express or implied,as to accuracy,completeness,timeliness,
or rights to the use of such information.King County shall not be liable for any general,special, indirect, incidental,or consequential
damages including, but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on
this map.Any sale of this map or information on this map is prohibited except by written permission of King County.
O 2013 D. R.STRONG Consulting Engineers Inc. 6 Saddlebrook Div. II
Technical Information Report Renton,Washington
FIGURE 3. DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS ',
?2013 D.R.STRoNG Consulting Engineers Ina 7 Saddlebrook Div. II
Technical Information Report Renton,Washington
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King County Area,Washington
AgC—Alderwood graveily sandy loam, 6 to 15 percent slopes '
Map Unit Setting SITE
Elevation:50 to 800 feet
Mean annual precipitation:25 to 60 inches
Mean annual airtemperature:48 to 52 degrees F
Frost-free period:180 to 220 days
Map Unit Composition
Alderwood and similar soils:95 percent I
Minor components:5 percent �
Description of Alderwood
Setting I
Landform:Moraines, till plains '�
Parent material:Basal till with some volcanic ash I
Properties and qualities �
Slope:6 to 15 percent ��
Depth to resfictive feature:24 to 40 inches to dense material �,
Drainage class:Moderately well drained
Capacity of the most limrting layer to transmit water(Ksat):Very low
to moderately low(0.00 to 0.06 in/hr)
Depth to wafer table:About 18 to 37 inches
Frequency of flooding:None
Frequency of ponding:None
Available wafer capacity:Very low(about 2.5 inches)
Interpretive groups
Land capability(nonirrigated):4s
Typical profile
0 to 12 inches:Gravelly sandy loam
O 2013 D. R.STRONG Consulting Engineers Inc. 8 Saddlebrook Div. II
Technical Information Report Renton,Washington
12 to 27 inches:Very gravelly sandy loam
27 to 60 inches:Very gravelly sandy loam
Minor Components
Norma
Percent of map unit:1 percent
Landform:Depressions
Bellingham
Percent of map unit: 1 percent
Landform:Depressions
Seattle
Percent of map unrt: 1 percent
Landform:Depressions
Tukwila
Percent of map unif: 1 percent
Landform:Depressions
Shalcar
Percent of map unit: 1 percent
Landform:Depressions
O 2013 D.R. STRONG Consulting Engineers Inc. 9 Saddlebrook Div. II
Technical Information Report Renton,Washington
SECTION II
CONDITIONS AND REQUIREMENTS SUMMARY
The Project must comply with the following Core and Special Requirements:
• C.R. #1 — Discharge at the Natural Location: The Site will discharge at its natural
discharge location.
• C.R. #2 — Offsite Analysis: An Offsite Analysis is included in Section III. The
Analysis describes the Site's runoff patterns in detail.
• C.R. #3 — Flow Control: The Project is required to adhere to Level 3 Flow Control
Standards per Adjustment 2012-03 for Saddlebrook Div. I. A detention pond will
provide flow control as required for both drainage basins within Saddlebrook Div. I
as well as Saddlebrook Div. II. The Project is required to "match developed
discharge durations to predeveloped durations for the range of predeveloped
discharge rates from 50% of the two-year peak flow up to the full 50-year peak
flow." (KCSWDM, Sec. 1.2) Also match developed peak discharge rates to
predeveloped peak discharge rates for the 2, 10 and 100 year return periods.
Furthermore, the Project must meet the Flow Control BMP requirements as
specified in Section 1.2.3.3 of the Manual. The Project will utilize basic dispersion
and restricted footprint to meet this requirement.
• C.R. #4 — Conveyance System: New pipe systems and ditches/channels are
required to 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. Pipe system structures and
ditches/channels may overtop for runoff events that exceed the 25-year design
capacity, provided the overflow from a 100-year runoff event does not create or
aggravate a "severe flooding problem" or "severe erosion problem" as defined in
C.R. #2. Any overflow occurring onsite for runoff events up to and including the
100-year event must discharge at the natural location for the project site. In
residential subdivisions, such overflow must be contained within an onsite drainage
easement, tract, covenant or public right-of-way. The proposed conveyance system
was analyzed using the KCBW program, and is capable of conveying the 100-year
peak storm without overtopping any structures or channels (see Section V).
• C.R. #5 — Erosion and Sediment Control: The Project provides the nine minimum
ESC measures.
• C.R. #6 — Maintenance and Operations: Maintenance of the proposed storm
drainage facility will be the responsibility of the City. An Operation and Maintenance
Manual is included in Section X.
• C.R. #7 — Financial Guarantees: Prior to commencing construction, the Applicant
must post a drainage facilities restoration and site stabilization financial guarantee.
For any constructed or modified drainage facilities to be maintained and operated by
the City, the Applicant must: 1) Post a drainage defect and maintenance financial
guarantee for a period of two years, and 2) Maintain the drainage facilities during the
O 2013 D.R. STRONG Consulting Engineers Inc. 1 D Saddlebrook Div. II
Technical Information Report Renton,Washington
two-year period following posting of the drainage defect and maintenance financial
guarantee.
• C.R. #8 - The Project is located in the Basic Water Quality Treatment area. i
Stormwater runoff will be collected in the detention pond and then conveyed through I
a BayFilter vault which will accommodate water quality requirements. I
• S.R. #1 — Other Adopted Area-Specific Requirements: Not applicable for this
Project. ',
• S.R. #2 — Floodplain/Floodway Delineation: Not applicable for this Project.
• S.R. #3 — Flood Protection Facilities: Not applicable for this Project.
• S.R. #4 — Source Control: Not applicable for this Project.
O 2013 D. R. STRONG Consulting Engineers Inc. 11 Saddlebrook Div. II
Technical Information Report Renton,Washington
SECTION III
OFF-SITE ANALYSIS
A Level One Downstream Analysis was prepared by DR Strong Consulting Engineers.
A copy has been included in this Section.
O 2013 D. R. STRONG Consulting Engineers Inc. 12 Saddlebrook Div. II
Technical Information Report Renton,Washington
LEVEL ONE DOWNSTREAM ANALYSIS
for
SADDLEBROOK DIV. II
Short Plat
13422 156`h Avenue SE, Renton,Washington
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DRS Project No. 13030
Renton File No. LUA 13-XXX
Owner/Applicant
ACH Homes, LLC
9675 SE 36t" Street, Suite 105
Mercer Island, WA 98040
Report Prepared by
� �
D. R. STRONG Consulting Engineers, Inc.
10604 N.E. 38th Place, Suite 232
Kirkland WA 98033
(425) 827-3063
Report Issue Date
May 14, 2013
�2012 D. R. STRONG Consulting Engineers Inc.
LEVEL ONE DOWNSTREAM ANALYSIS
SADDLEBROOK DIV. II
TABLE OF CONTENTS
TASK 1 DEFINE AND MAP THE STUDY AREA .........................................................1
TASK 2 RESOURCE REVIEW.....................................................................................5
TASK 3 FIELD INSPECTION .....................................................................................15
Upstream Tributary Area............................................................................................ 15
General Onsite and Offsite Drainage Description ...................................................... 15
TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS...16
Drainage System Description..................................................................................... 16
DownstreamPath................................................................................................... 16
TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS.........................21
List of Figures
Figure1 Vicinity Map.......................................................................................................2
Figure2 Site Map ............................................................................................................3
Figure 3 King County iMap Topography..........................................................................4
Figure 4 Streams and 100-Year Floodplains and Floodway............................................6
Figure 5 King County iMap Wetlands ..............................................................................7
Figure 6 King County iMap Erosion Hazard Areas ..........................................................8
Figure 7 King County iMap Landslide Hazard Areas.......................................................9
Figure 8 King County iMap Seismic Hazard Areas........................................................10
Figure 9 FEMA— Flood Insurance Rate Map ................................................................11
Figure 10 King County iMap Drainage Complaints........................................................12
Figure 11 USDA King County Soils Survey Map ...........................................................13
Figure 12 Downstream Map ..........................................................................................18
Figure 13 Downstream Table ........................................................................................19
02013 D. R.STRONG Consulting Engineers Inc. Page i of i
Level One Downstream Analysis Saddlebrook Div.II Short Plat City of Renton
TASK 1 DEFINE AND MAP THE STUDY AREA
This Offsite Analysis was prepared in accordance with Core Requirement #2, Section
1.2.2 of the 2009 King County Surface Water Design Manual (Manual). The Site is
located at 13422 156th Avenue SE in Renton, Washington.
See Figure 1, Figure 2, and Figure 3 for maps of the study area.
�2013 D.R.STRONG Consutting Engineers Inc. Page 1
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 1
VICINITY MAP
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The information included on this map has been compiled by King County staff from a variety of sources and is subject to change
without notice. King County makes no representations or warranties,express or implied, as to accuracy, completeness, timeliness,
or rights to the use of such information.King County shall not be liable for any general,speciai, indirect, incidental, or consequential
damages including, but not Iimited to, lost revenues or lost profits resulting from the use or misuse of the information contained on
this map.Any sale of this map or information on this map is prohibited except by written permission of King County.
02013 D. R.STRONG Consulting Engineers Inc. Page 2
� Level One Downstream Analysis Saddlebrook Div.II Short Plat City of Renton
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FIGURE 2 �',
SITE MAP '
�2013 D. R.STRONG Consulting Engineers Inc. Page 3
Level One Do�vnstream Analysis Saddlebrook Div. II Short Plat City of Renton
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FIGURE 3
KING COUNTY IMAP TOPOGRAPHY
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02013 D. R.STRONG Consulting Engineers Inc. Page 4
Level One Downstream Analysis Saddlebrook Div.II Short Plat City of Renton
TASK 2 RESOURCE REVIEW
• Adopted Basin Plans: May Creek Basin Action Plan was adopted in Apri!2001.
• Floodplain/Floodway (FEMA) Map: No floodplains exisf on site, See Figure 9.
• Other OfFsite Analysis Reports: Saddlebrook Div. 1
• Sensitive Areas Folio Maps: See Figures 4-8 for documentation of the distance
downstream from the proposed project to the nearest critical areas. lncJuded, are
sections of the King County Sensitive Areas Folio which indicate the following: �'
• Figure 4 Streams and 100-Year Floodplains and Floodway: There is a
Class 2 Stream within one mile of the Site along the downstream path.
• Figure 5 Wetlands: There are no mapped Wetlands within one mile of the
Site along the downstream path.
• Figure 6 Erosion Hazard: There are mapped Erosion Hazard Areas
within one mile of the Site along fhe downstream path.
• Figure 7 Landslide Hazard: There are mapped Landslide Hazard Areas
within one mile of the Site along the downstream path.
• Figure 8 Seismic Hazard: There are mapped Seismic Nazard Areas
within one mile of the Site along the downstream pafh.
• DNRP Drainage Complaints and Studies: As shown in Figure 10,there are no
drainage complaints, within the last �0 years, within 1 mile of the Site along the
downstream path.
• Road Drainage Problems: None noted.
• USDA King County Soils Survey: See Figure 11.
• Wetlands Inventory: Vol. 3South (9990) — The wetland inventory revealed no
additional wetlands within the downstream path.
• Migrating River Studies: None are applicable to the site.
• Washington State Department of Ecology's latest published Clean Water Act Section
303d list of polluted waters: None listed along the downstream path.
• King County Designated Water Quality Problems: None at this time.
• Adopted Stormwater Compliance Plans: None applicable to this site.
• Basin Reconnaissance Summary Reports: None available at this time
02013 D. R. STRONG Consulting Engineers Inc. Page 5
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 4
STREAMS AND 100-YEAR FLOODPLAINS AND FLOODWAY
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02013 D. R.STRONG Consulting Engineers Inc. Page 6
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 5
KING COUNTY IMAP WETLANDS �
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Legend
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(cant)
�2013 D. R.STRONG Consulting Engineers Inc. Page 7
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 6 II
KING COUNTY IMAP EROSION HAZARD AREAS ��
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� d � �-,"-�` I s ` .. e'+o a � _ �. sc i.wa sr� '. �
� � _� . ! • �
M �' b� �. - 5e�aaTHst- �� 0. � I
_ �` -
s � Se,� r� d \ �. se uar�ac �til bl -; - _ . . _ : . � . �-.- �
� ��` `'R � �" y � d d � � � � - i-.... ..- �. -
� � � 'sro .��• � � � � �siusrwsr � a}.y . . t
� i
4+�' \ � h' � 5f � p� �
� � � � � � k � l �
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\ � .
� G
i �_, \�� � _ .
�,� 8a i p ' " t�
-- �ti.� � ss,m�sr �f� �'
�,\ � '
�
!ff ,r•`` /,.,'
- Cedar River ' � ��
�". � �'`S'`'Qy� d � t4
� � 3 � `�� � �1 �' �
��s�vo I z _ � g � �. '-�,� .
R \ �-� y �-'---
o /(,l,f � `'
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� � d � - \` -� �•���. ��i . � �����-��' 1�l
r.- �� �� � �vG,J) . �'-
SE��TMR . � ' \ � I':I,�'c�.�'��.�U^—'�7� : h`�
.�p ' � `` . `ASN
S� �� 7 ���51 �� - . _._..SE RENiON AIAPLE�VALLEYRD ._._.. . .
o � � ..'... _ ._. .
� �t
��RSE � �MS� 'p 287<R
Le ge nd
� Highlighted Feature ' p,ta;,y
� � Cavnty Boundary �oca�
x Mountain Peaks Parcels
Highways i—I Lakes and Large Riv�rs
l_�
S#reets �;I 5treams
��ph,ray SAO Erosion
(cont}
02013 D. R.STRONG Consulting Engineers Inc. Page 8
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 7
KING COUNTY IMAP LANDSLIDE HAZARD AREAS
SITE
2
. >j ��C, � � SEI]15T5T \�_�� �' . �
f, �
a��r+asr � , �' � sfuisra. � �; o
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ME tg(R �
< $ �. NE15fy7 '�N
�1]Y:
d � Jy� greosr t2 ss�sm�sr sftMN� jm
Q � � SEb'O5T a �. ' - -. . --SE 1347H
Y z
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y� � SEAA p � i .
Y �
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o i� d sE nan�at �—` �i R ,' �Y
// ��' �� . � � r'- � � � �E��fN N <
. U. SE 174TH 0. � $E I.�il/PL ��5[STII R � �I . ri^I
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51 7� $I
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Q 6' _ ��'SE 62��P� SE ETN ST �o� � i � .
Q . � � 4`~� ��l � - SEt/Yi05T `, �:OST•
y � ���•.�� gt R � . � . �
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i -� .;,\ . � � . ,/ A � o
� r7 'r
W �! �_ �`,� �' /� %�/� rr:�%� '7/ :r/r �¢f jr��.^��iT:/
[eda�r River �; ��� �� //��//////j//////��// / /��%���j/
'� I 3 �' ��' � �K-��'�/ �," �1.:�[_.._ ��/�js�f " '-_.- - -
/�\� �'ato I r ,�: � a � � -� -'.. -
� �� R ' , � ,,°SS �' � '�
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� . �j / � � . � . , .,
r••`�'� �����.��/ � -�v j��i, // ��Sp-� � " ./i.. . . - '_SE REflTON 41A/'LE VALLEY RO +
i/'"i ///
r�R� ��t �jl �'�if/ .�i��.�� .�i, .�i/.!jj/////���i������//�i
/ ����� i'� i/'0 287�R /� �
� Legend
Highlighted Feature ' ��h
�_� County Boundary �
y� Mountain Peaks Parcels
Highways f—I Lakes and Large Rivers
L—I
Streets �f 5ireams
Hghw�y � SAO Lend5lide
{cont)
�:2013 D. R.STRONG Consulting Engineers Inc. Page 9
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 8
KING COUNTY �MAP SEISMIC HAZARD AREAS
SITE
� � 61 sE u,sr sr � ___�� ;
� ss�a�sra ;
Renton Z � �fy/� �, ;�
W W `¢��$T �H. {
� a �r . . ��p, I � `s2 . E
z g
� � c3 �" � SE����t SEtis� si�. ZJ :rD�rl
N � - T4' � NE157R �'+
�yy ; NE15T5'(
.yQ�.� �� � SE 17sTFt ST SE ISRN$} � ��
sezyper � . S'v � �mosr �; H sE��3nrsr � . 1--�,— .,"_sE�3arH
!
5£2NOCT Qq �i� a � SFt15T�{yT . . .
T * SF�jPL � �q '��F75TI t�'f/1Ai .
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< a d � � ;.
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d � sE�un�ct ; � �; �
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/$ � � �- !:__ -.,'__ .'._.'_ SE�1d4iHST _,� 6�
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. f. LeVAi�Rp�\�\�� \ \\•\,�\\\\� ��\o,'.\`:����� ''�\��C\�\����.����\�
2655
L�ge nd
� Highlighted Feature :' ����
� � Gounty 6aundary �oc�
x Mountairz Peaks Parcels
Highways � Lakes and Larc�e Rivers
Straet� �.,-/ Stfeams
tl�ghway � SAfl Seismic
(cont)
��2013 D. R. STRONG Consulting Engineers Inc. Page 10
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
- FIGURE 9
�
FEMA - FL40D INSURANCE RATE MAP
� �
i
- �:
��.
5,_�I�iFE.-.si �52:�9 s-r..r[r �y
. -,�
,L
Q
zorve X 14 -
5���17:-.::.=7 t'sfiTl; Sir�iET �=
�
1:73'f� i'l:.?:(
LEGEND
� snra:u.r�oc�n r�•iz�hu ,uie,�s inuho:cm:i>
Gl'700-YF1.R PI.OQD
ZONE 0. �._,l�i.�,il.�d..�.nx�n.�k-H�,n,i..��..
ZONE AE it�.Y i;..•:I rE�,.e:��,.�Ma�.m:M�l
ZONE AH IY•.A�knh.x 7!�� t i„a•v::.�8r.�
�a �na:eny,. I:au� IL�aI`�di.,ii>�-.
,w�.�rmnari.
ZONf AO IG.-.I cti}eh�d i a.1 u. ..•�C:
a�ri d�q,hG : �rago ��;r.'n
..,;rya.r.,�.:,.v�•,,�"as„�.n r,n n,.,s":.
.r4ita. .�ti�d�trm�ui�.l ..
ZONE A99 T•� F<- �u:n.<��-i fr•An It�i-.ca ib.�!{,
(�-�k•r.i? fl<.v: i�nae�tirx� .�J�.n� �
�.,ro.rit:1«x�.n�L+ax'��.^.alkn<�1rM-ini.*irl
ZONE V G::d.d fl.xd u;d� »�ke;�r n.uuA �.
.rzii�n,.u�Unc I:.KI i.6v.nrn SeYrrirtuwL
ZONE VE (�.r.�al +1•v�J xdh .d�K�in hvari �,
� .xfi.vi.: Srta• F�.rl ��6_•.Hbxu tirn•�mi�..L
FLOOUI,4':\Y;\R[.L5 IN 70NE AE
� OTHER(i_(X)D AREAS
ZONE% .ir:m�h�SUIi.�N,Ikud:.veu��f H.�)..yr.r
!4uii �rilh s�•r.� d�'F'ah> �9 I.z. 4:,��
I 4xq < <:il�duib.yt� .� , k.s tiu:n
� wi�,-.rt•F m;N: ...t . �p,n.rxd 1��
U�:�=:,(n.m x.'rnzor 8id
� or�+ea,�ie[ns
ZONE X v., dcle�m:md tn M os;�i�u:•}y.:a
i4,.:l�wm.
ZONE D , ..h.l. iiir:d ha;.w�d+ ,..
w+,k��nn mal.
02013 D. R.STRONG Consulting Engineers Inc. Page 11
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 10
KING COUNTY IMAP DRAINAGE COMPLAINTS
SITE
. �e ', ' ' sr sF��is7R �
V '�
Renton = � � �* ���.o-s, _
�' 4 ,��a�`— ,
_ ( 2W tl ��OCi SE1 ST �^� � .
� � �`,W ��-.. hE�STFt �ii �.
N
� � '; Nf IST ST .� � �.
� SE IyT1 ST SE 11nN S�
g � � ' - SE 1]diM Si
SENOCT � C�� i �arosr N.. � �asr�,sr �� s��ssrMsr I -
SE31DCT Q � S£3+OST� 1liT��F� �.
LSr- � � SF A�0 0. �: � .
� _ � M . .. ._ �.SE t7ATN ST
`� � �
5 d �
� F � � - �»?n�a� y�
M M .. �S � ? ���
n � 5E�]�n�vt '�.sEm�tt ' � Sfri Msi G
9
� SE��TI R 1� SE S7N R � �� !
N FF 4 N�u
< S 5£ItlTMPi }� � <�-... SE 1�OTN ST'
� ����R � 6� < g7fN5T $) � I
d sE,nsTct ��aa i
- - _�. � - � SE 7a7UO5i � OP � SEdT��sr 5
M � -_—� '�'�'sE`caN 'F,�,o� ,! - ►�s;r ' sE�mw
d � � �. sE i�o sr � bl f ,�W\''y
� � _ se u�an at 1` : d y�
q - � �� se t�urH sr a � �:
� se, � � �,.�R ai a� �, � -_�- �- -
�"R �' ;.. � � i d _ ��Ff� SE,as,;�sT ^ ; Y --
� n �� � � � � � d i.a f ���'JN57.
� ` w � � � �
!H �� � s d � d �
�` � �' SE I,SfN ST � � � � � ,.,� � /
� � q �
���� - i���• �. 7 �
� S 1
.; g', .l� P sE u9tH sr i
• ,` qy�,JR ,f' �,_ � 1 � . _
Cedar River � �7 1 Y i�y� } , �r+
.:�\ �` .! � y=C� � ��.� %�
ix
�,'� � —-- _tjj; �,� � * 1 4
d
� � � ��,�s'4o � �! � sE�sa� ;...
'^:rrT�, � �' \�. �' �uv���sc _
+�fAP���+(l£y'2p y� � 0 ^\^ 2855R
Legu nd
(� Sol�ctod P�rcol• ��qnM+r
�j County 8oundary �neu�,
x Mounfaln P�ake �Oa
HlgAways Percols
�j Incorparatud Area U Lakos md Largo Rivon
5treets �i Streams
(cont) Ora:napo Comp'alnts
��2013 D. R.STRONG Consulting Engineers Inc. Page 12
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 11 I
USDA KING COUNTY SOILS SURVEY MAP I
� _
��
�
� �
�; _�.
�= ���' ::
, . � ..
r . _ , , up :_
, _ � , ._
�. ._
, , ,
,,;t ' 4',' yl
�� f �". :�.:
� �s. ��£.
, ��x,�
� X.:.
� � w .�
I k;
.�_
; .�,: +....« ' �.
_. _.�_. s , � .
..' �� �f � ..�` ..:
I -�. '£�.--_ ��
. .. . .. ,�'-. `¢ , ,,. .� ...-... . _ .:a:... . , �.
':$
'
AgC—Alderwood gravelly sandy loam, 6 to 15 percent slopes
Map Unit Setting
• Elevation: 50 to 800 feet
• Mean annual precipitation: 25 to 60 inches
• Mean annual air temperature: 48 to 52 degrees F
• Frost-free period: 180 to 220 days
Map Unit Composition
• Alderwood and similar soils: 95 percent
• Minor components: 5 percent
Description of Alderwood
Setting
• Landform: Moraines, till plains
• Parent material: Basal till with some volcanic ash
• Properties and qualities
• Slope: 6 to 15 percent
• Depth to restrictive feature: 24 to 40 inches to dense material
� Drainage class: Moderately well drained
• Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately
low (0.00 to 0.06 in/hr)
<J2013 D. R. STRONG Consulting Engineers Inc. Page 13
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
• Depth to water table: About 18 to 37 inches
• Frequency of flooding: None
• Frequency of ponding: None
� Available water capacity: Very low (about 2.5 inches)
Interpretive groups
• Land capability (nonirrigated): 4s '
Typical profile
• 0 to 12 inches: Gravelly sandy loam
• 12 to 27 inches: Very gravelly sandy loam
• 27 to 60 inches: Very gravelly sandy loam
Minor Components
Norma
• Percent of map unit: 1 percent
• Landform: Depressions
Bellingham
• Percent of map unit: 1 percent �
� Landform: Depressions
Seattle
• Percent of map unit: 1 percent
• Landform: Depressions
Tukwila
• Percent of map unit: 1 percent
• Landform: Depressions
Shalcar
• Percent of map unit: 1 percent
• Landform: Depressions
02013 D.R.STRONG Consulting Engineers Inc. Page 14
Level One Downstream Analysis Saddlebrook Div.II Short Plat City of Renton
TASK 3 FIELD INSPECTION
UPSTREAM TRIBUTARY AREA
In evaluating the upstream area, we reviewed King County IMAP aerial topography and
imagery and conducted field reconnaissance and have concluded that upstream
tributary area for the Site is negligible. The upstream properties developed portions
drain in southeasterly and southwesterly directions almost directly to the respective
rights of way.
GENERAL ONSITE AND OFFSITE DRAINAGE DESCRIPTION
The 0.89 acre parcel contains a single natural discharge point near the southwest
corner of the Site. The Site sheet flows towards the southwest corner of the Site and
into the right-of-way. From there, it is collected into the conveyance system within 156tn
Avenue and is conveyed south.
Runoff from the developed Site will be collected and conveyed by a typical catch basin/
pipe network to a detention pond in the southwest corner of Saddlebrook Div. I. The
pond will discharge to the conveyance system in 156t" Avenue SE.
02013 D. R.STRONG Consulting Engineers Inc. Page 15
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM
DESCRIPTIONS
DRAINAGE SYSTEM DESCRIPTION
The downstream analysis is further illustrated and detailed in the Downstream Map and
Downstream Table located in Appendix A. The downstream area is located within the
Cedar River; more specifically the Lower Cedar River sub basin. The downstream area
was evaluated by reviewing available resources, and by conducting a field
reconnaissance on July 12, 2012 under overcast conditions.
Downstream Path
Point "A" is the natural discharge point of the Site. Runoff exits the Site as sheet flow to
the southwest.
From Point "A" to Point "B", runoff heads southwest as sheet flow and into a Type 1
Catch Basin located along the east side of 156th Avenue SE. (0' - ±50')
From Point "B" to Point "C", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 1 CB with a storm manhole lid. (±50'-±350')
From Point "C" to Point "D", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 1 Catch Basin. (±350' — ±440')
From Point "D" to Point "E", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 1 Catch Basin. (±440' — ±665')
From Point "E" to Point "F", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 2 Catch Basin. (±665' — ±680')
From Point "F" to Point "G", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 2 Catch Basin. (±680' — ±695')
From Point "G" to Point "H", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 2 Catch Basin. (±695' — ±770')
From Point "H" to Point "I", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 2 Catch Basin. (±770' — ±815')
From Point "I" to Point "J", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 2 Catch Basin. (±815' — ±890')
From Point "J" to Point "K", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 2 Catch Basin. (±890' — ±930')
From Point "K" to Point "L", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 1 Catch Basin. (±930' — ±945')
From Point "L" to Point "M", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 1 Catch Basin. (±945' — ±1,085')
From Point "M" to Point "N", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 1 Catch Basin. (±1,085' —±1,185')
02013 D. R. STRONG Consulting Engineers Inc. Page 16
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
From Point "N" to Point "O", runoff continues south as pipe flow via a 12-inch PVC Pipe.
The pipe connects to a Type 1 Catch Basin. (±1,185' — ±1,260')
From Point "O" to Point "P", runoff continues south as pipe flaw via a 12-inch PVC Pipe.
The pipe connects to a Type 1 Catch Basin. (±1,260' — ±1,360')
Qualitative Analysis of the downstream path continued along 156th Avenue SE. The
analysis was concluded at the intersection of 156th Avenue SE and SE 144t" Street.
��2013 D. R.STRONG Consulting Engineers Inc. Page 17
Level One Do�vnstream Analysis Saddlebrook Div. II Short Plat City of Renton
FIGURE 12
DOWNSTREAM MAP ,
,
; -
, , .
I �'�
I ! �
� �- �
02013 D.R.STRONG Consulting Engineers Inc. Page 18
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
�
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FIGURE 13
DOWNSTREAM TABLE
Basin: Cedar River Subbasin Name: Lower Cedar River Subbasin Number: N/A
Symbol Drainage Drainage Component Slope Distance Existing Potential Observations of field inspector
Component Type, Description From site Problems Problems resource reviewer, or resident
Name, and Size Dischar e
Type: sheet flow, Constrictions, under capacity, ponding, tributary area, likelihood of probiem,
See map swale, Stream, drainage basin,vegetation,cover, % 1/4 mi=1,320 ft overtopping,flooding, habitat or organism overflow pathways,potential impacts.
channel, pipe, depth,type of sensitive area,volume destruction, scouring, bank sloughing,
Pond;Size:diameter sedimentation, incision, other erosion
Surface area
A Natural Discharge Sheet flow across southwest property ±0' None Observed None Anticipated
Point corner
A-B Southwesterly Sheet Sheet flow into a Type 1 CB t50' None Observed None Anticipated
Flow
B-C Southerly Pipe Flow 12"PVC to a Type 1 CB ±350' None Observed None Anticipated Trickle Fiow
C-D Southerly Pipe Flow 12"PVC to a Type 1 CB ±440' None Observed None Anticipated Trickle Flow
D-E Southerly Pipe Flow 12"PVC to a Type 1 CB ±665' None Observed None Anticipated Trickle Flow
E-F Southerly Pipe Flow 12"PVC to a Type 2 CB ±680' None Observed None Anticipated Trickle Flow
F-G Southerly Pipe Flow 12"PVC to a Type 2 CB 1695' None Observed None Anticipated Trickle Flow
G-H Southerly Pipe Flow 12"PVC to a Type 2 CB t770' None Obsenred None Anticipated Trickle Flow
H-I Southerly Pipe Flow 12"PVC to a Type 2 CB ±815' None Observed None Anticipated No Flow
I-J Southerly Pipe Flow 12"PVC to a Type 2 CB ±890' None Observed None Anticipated No Flow
J-K Southerly Pipe Flow 12"PVC to a Type 2 CB t930' None Observed None Anticipated No Flow
c�2013 D. R. STRONG Consulting Engineers Inc. Page 19
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
K-L Southerly Pipe Flow 12"PVC to a Type 1 CB ±945' None Observed None Anticipated No Flow
L-M Southerly Pipe Flow 12"PVC to a Type 1 CB t1,085' None Observed None Anticipated No Flow
M-N Southerly Pipe Flow 12"PVC to a Type 1 CB ±1,185' None Observed None Anticipated No Flow
N-O Southerly Pipe Flow 12"PVC to a Type 1 CB t1,260' None Observed None Anticipated No Flow
O-P Southeriy Pipe Flow 12"PVC to a Type 1 CB ±1,360' None Observed None Anticipated No Flow
c�-�2013 D. R. STRONG Consulting Engineers Inc. Page 20
Level One Downstream Analysis Saddlebrook Div.II Short Plat City of Renton
TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS
A review of the King County Water and Land Resources Division — Drainage Services
Section Documented Drainage Complaints within one mile of the downstream flow
paths revealed no complaints within the last ten years.
The project should not create any problems as specified in Section 1.2.2.1 of the
Manual and therefore is not required to provide Drainage Problem Impact Mitigation
subject to the requirements of Section 1.2.2.2.
Project runoff will be collected and released per the Manual's requirements to
accommodate Level 3 Flood Problem Flow Control and Basic Water Quality
requirements. During construction, standard sediment and erosion control methods will
be utilized. This will include the use of a stabilized construction entrance, perimeter silt
fencing, and other necessary measures to minimize soil erosion during construction.
R:1201310\13030131Documents\ReportslPreliminarylLevel 1 DS 13030.docx
02013 D. R.STRONG Consulting Engineers Inc. � Page 21
Level One Downstream Analysis Saddlebrook Div. II Short Plat City of Renton
SECTION IV
FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
As previously stated, Saddlebrook Div. II will utilize the detention facility within
Saddlebrook Div. I to meet flow control requirements. For purposes of facility sizing,
Divisions I and II will be analyzed as one project.
EXISTING SITE HYDROLOGY (PARTA)
KCRTS was used to model the peak runoff from the Site. Per Table 3.2.2.b of the
Manual the soil type is modeled as "Till" for the Alderwood gravelly sandy loam SCS
classification as shown in Figure 4. Soils. The entire Site is modeled as "Forest."
Results of the KCRTS analysis are included in this section.
Modeling input
Land cover Entire
Site
Till forest(ac) 5.544
Till Grass (ac) 0.000
Wetland (ac) 0.000
Impervious (ac) 0.000
Scale Factor: 1.00
Time Step: Hourly
Data Type: Reduced
Project location: Seatac
Total Area: 5.544
Table 1 Pre-Developed KCRTS Modeling Input
Modeling results
Entire Site
�1c.,: �re��en�y :_r.a=,;-s-s
Time Series File:prede:-.��f
Project Location:Sea-T=,c
---Annual Peak Flow Rates-- ---Flow �reque��y ;r_�alysis-------
Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prc�
(CFS} (CFS) Period
0.350 2 2/09/Ol 18:00 0.447 1 100.00 0. 990
0.095 7 1/06/02 3:00 0.350 2 25.00 0. 960
0.259 4 2/28/03 3:00 0.268 3 10.00 0. 900
0.009 8 3/24/04 20:00 0.259 4 5.00 0.800
0.154 6 1/05/05 8:00 0.226 5 3.00 0. 667
0.268 3 1/18/06 21:00 0. 154 6 2.00 0.50G
0.226 5 11/24/06 4 :00 0.095 7 1.30 0.231
0.447 1 1/09/08 9:00 0.009 8 1.10 0.091
Ccmputed Fea'.rs 0. !15 5C.0^ 0, 930
O 2013 D.R.STRONG Consulting Engineers Inc. 13 Saddlebrook Div. II
Technical Information Report Renton,Washington
FIGURE 5. PREDEVELOPMEN`f AREA MAP
�2013 D. R. STRONG Consuiting Engineers Inc. 14 Saddlebrook Div. ii
Technical Information Report Renton,Washington
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A REA BREA KD O WN L EGEND
� � � PROJECT BDUNDARY
TOTAL EXlSTING SITE AREA: 228,512 S.F. (5.25 ACRES)
NORTH
TOTAL PROJECT AREA: 241,515 S.F. (5.54 ACRES) � TILL FOREST GRAPHIC SCALE DR^FT�o er. rca
TOTAL PROJECT DEl/ELOPMENT AREA: 241,515 S.F. (5.54 AC) 0 40 80 120 oEs,�cN�a ar. rcP
PROJECT ENGINE£R: MAJ
MODELED AS TILL FOREST �� oA�: os.3o.�3 ,
1 INCH - 80 FT. ��o�ecrrro.: rsoso ,
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CGFYF.:GHT�2012, C.P.. STRO�.G CONSU'_-RJG E'JGINEE4S It.�. '�
DEVELOPED SITE HYDROLOGY (PART B)
Soil type �
The soil types are unchanged from pre-developed conditions. '
Land covers
KCRTS was used to model the developed peak runoff from the Site. The portions of
the Site within the proposed clearing limits tributary to the proposed detention pond
were modeled as "Till Grass" and Impervious as appropriate. Results of the KCRTS
analysis are included in this section.
Modeling input
Land cover Entire
Site
Till forest (ac) 0.000
Till Grass (ac) 2.540
Wetland (ac) 0.000
Impervious (ac) 2.857
Scale Factor: 1.00
Time Step: Hourly
Data Type: Reduced
Project location: Seatac
Total Area: 5.397
Table 2 Developed KCRTS Modeling Input
Detailed Impervious Area Breakdown:
TOTAL LOT AREA= 169295 S.F. IMPERVIOUS=70278 S.F. PERVIOUS= 99017 S.F.
TOTAL R.O.W.AREA=39688 S.F. 100%IMPERVIOUS=39688 S.F. 0% PERVIOUS
TRACT A AREA(DIV. I)=20130 S.F. 50%IMPERVIOUS=10065 S.F. 50%a PERVIOUS= 10065 S.F.
TRACT A AREA(DIV. II)=4412 S.F. IMPERVIOUS=4412 S.F. PERVIOUS=0 S.F.
TRACT B AREA(DIV. II) =1554 IMPERVIOUS=0 S.F. PERVIOUS= 1,554 S.F.
:�2013 D.R.STRONG Consulting Engineers Inc. 15 Saddlebrook Div. II
Technical Information Report Renton,Washington
Modeling Results
Saddlebrook Div. I and Div. II
rlow Frequency Analysis
Time Series File:rdin.tsf
Froject Location:Sea-Tac
---Annual Peak Flow Rates--- -----F1ow Frequency Analysis-------
Flow Rate Rank Ti.ne of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS) Period
0. 920 6 2/09/Ol 2:00 1. 89 1 100. 00 0.990
0.726 8 1/05/02 16:00 1.11 2 25.00 0.960
1.11 3 2/27/03 7:00 1.10 3 10.00 0.900
0.759 7 8/26/04 2:00 0. 973 4 5.00 0.800
0.920 5 10/28/04 16:00 0. 920 5 3.00 0.667
0. 973 4 1/18/06 16:00 0.920 6 2.00 0.500
1.10 2 10/26/06 0:00 0.759 7 1.30 0.231
89 1 1/09/08 6:00 0.726 8 1.10 0.091
Co puted Peaks 1. 63 50.00 0.980
'j ,
O 2013 D. R.STRONG Consulting Engineers Inc. 16 Saddlebrook Div. II
Technical Information Report Renton,Washington
BYPASS AREA HYDROLOGY
Modeling input
Land cover Entire
Site
Till forest(ac) 0.000
Till Grass (ac) 0.053
Wetland (ac) 0.000
Impervious (ac) 0.095
Scale Factor: 1.00
Time Step: Hourly
Data Type: Reduced
Project location: Seatac
Total Area: 0.148
Table 3 Bypass KCRTS Modeling Input
Modeling results
Bypass
Flow �requency �ralys-s
Tine Series File:bypass.tsf
Project Location:Sea-Tac
---Annual Peak F1ow Rates--- -----Flcw Frequency Analysis-------
Flcw Rate Rar.k Time of Peak - - Peaks - - Rank Returz ?rob
(CFS) (CFS) Period
0.028 5 2/09/Ol 2:00 0.056 1 100.00 0. 990
0.023 8 1/05/02 16:00 0.036 2 25.00 0. 960
0.034 2 2/27/03 7:00 0.034 3 10.00 0. 900
0.025 7 8/26/04 2:00 0.030 4 5.00 0.800
0.029 6 10/28/04 16:00 0.029 5 3.00 0.667
0.030 4 1/18/06 16:00 0.028 6 2.00 0.500
0. 036 3 10/26/06 0:00 0.025 7 1.30 0.231
0.056 1 1/09/08 6: 00 0.023 8 1.1G 0.091
Computed Peaks G.C�'_9 �� . 00 �. 980
The flow control facility is designed to compensate for uncontrolled bypass. The 100-
year discharge from the bypass areas is 0.056 cfs, which is less than the 0.4 cfs
threshold. There should be no adverse downstream impacts to the downstream
drainage system created by the runoff from the bypass.
There is a bypass area associated with each TDA of Saddlebrook Div. I. For purposes
of detention calculations, both bypass areas were used as the approved drainage
adjustment calls for a combination of the TDA's.
The onsite bypass areas satisfy all the requirements set forth in the Manual, Section 1.2
with the exception of TDA East (Saddlebrook Div. I) as it pertains to convergence with
the downstream path of the facility within a quarter mile. This is further detailed in the
following section.
G 2013 D. R. STRONG Consulting Engineers Inc. 17 Saddlebrook Div. II
Technical Information Report Renton,Washington
FIGURE 6. POST DEVELOPMENT AREA MAP
G 2013 D. R.STRONG Consulting Engineers Inc. 18 Saddlebrook Div. II ,
Technical Information Report Renton,Washington '
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PERFORMANCE STANDARDS (PART C)
The Project is required to meet the Level 3 Flow Control and Basic Water Quality
Treatment requirements. The Level 3 performance requires the developed condition
discharge rates to match the predeveloped rates ranging from 50% of the two-year
peak up to the 50-year peak. Also match developed peak discharge rates to !
predeveloped peak discharge rates for the 2-, 10- and 100-year return periods.
The Basic Water Quality Treatment goal is to remove 80% of TSS for flows or volumes
up to and including the WQ design flow or volume. �
Conve ance criteria for the Pro'ect re uire that all new i es be desi ned to conve
Y 1 q pp 9 Y
and contain (at minimum) the 25-year peak flow. i
FLOW CONTROL SYSTEM (PART D) ,
Both Saddlebrook Div. I and Div. II will utilize a detention pond meeting the Level 3
Flow Control Criteria. The King County Runoff Time Series (KCRTS) software was
used to size the detention facility. The detention pond design information is included in �
this section.
FLOW CONTROL BMP SELECTION
Subdivision projects are required to mitigate for impervious surface equal to a minimum
of 10% of each lot area by use of Flow Control Best Management Practices (BMP's). i
Projects are required to first analyze the feasibility of dispersal and infiltration before
choosing another method. The Site will utilize basic dispersion with the use of splash
blocks. Two splash blocks mitigating a total of 1,400 s.f. of impervious area, will be
installed with each residence. This shall mitigate for 12.75% to 13.77% of impervious
area for each lot. Also, each lot will be restricted to an area less than 4,000 s.f. (see
table below).
ROOF AREA ROUTED TO RESTRICTED IMPERVIOUS TOTAL AREA PERCENT IMPERVIOUS II
LOT N0. LOT AREA(S.F.) SPLASH BLOCK(S.F.) AREA PER LOT MITIGATED MITIGATED I
1 10169 1400 3505 1895 18.64 I
2 10983 1400 3485 1915 17.44 �
3 10877 1400 3885 1515 13.93
:�2013 D. R.STRONG Consulting Engineers Inc. 19 Saddlebrook Div. II
Technical Information Report Renton,Washington
FLOW CONTROL SYSTEM
The Project will utilize one detention pond to meet Level Three Flow Control criteria for
the Site. The King County KCRTS software was used to size the detention facility.
Saddlebrook Div. I and Sadd/ebrook Div. Il
Retention/Detention Facility
Type of Facility: Detention Pond
Side Slope: 3.00 H:1V
Pond Bottom Leng�h: 71.50 ft
Pond Bottom Width: 71.50 ft
Pond Bottom Area: 5112. sq. ft
Top Area at 1 ft. FB: '_4496. sq. ft
0. 333 ac�es
Eftective Storage �epth: 7.15 ft I
Stage 0 Elevation: 488. 35 ft I
�torace Volume: 62868. cu. ft 'I
1. 443 ac-ft ''
R.iser Head: 7. 1� ft
R;_ser Diar-te�er: 1�. �0 inches
`:�rr,�e-- ct crifi��s: 3 '
�ull Head Pipe
C�ific� '� �ei,rt Diari�ter Discharge Diameter
(rt) ;in) (CFS) (in) '
"- 0.00 1.11 0.090
2 4.95 2.14 0.185 6.0
3 6.37 2.54 0.155 6.0
Top Notch Weir: None
Cutflow Rating Curve: none
Stage Elevation Storage Discharge Percolation Surr Area
(�t) (ft) (cu. ft) (ac-ft) (cfs) (cfs) (sq. ft)
J .00 488.35 0. 0.000 0.000 0.00 5112.
7 .01 488.36 51. 0.001 0.004 0.00 5121.
� .02 488.37 102. 0.002 0.005 0.00 5129.
;; .03 488.38 154. 0.004 0.006 0.00 5138.
.' .05 488.40 257. 0.006 0.007 0.00 5155.
" .06 488.41 308. 0.007 0.008 0.00 5i64.
C .07 488.42 360. 0.008 0.009 0.00 5172.
� .08 488.43 412. 0.009 0.010 0.00 5181.
; .09 488.44 464. 0.011 0.010 0.00 5189.
C . 10 488.45 516. 0.012 0.011 0.00 5198.
C .24 488.59 1252. 0.029 0.017 0.00 5320.
C .38 488.73 2005. 0.046 0.021 0.00 5443.
C .53 488.88 2832. 0.065 0.024 0.00 5577.
C. 67 489.02 3621. 0.083 0.027 0.00 5703.
C.81 489.16 4429. 0.102 0.030 0.00 5831.
C. 95 489.30 5254 . 0.121 0.033 0.00 5959.
1.09 489.44 6097. 0.140 0.035 0.00 6090.
1.23 489.58 6959. 0.160 0.037 0.00 6222.
1.37 489.72 7839. 0. 180 0.039 0.00 6355. ,
1.51 489.86 8739. 0.201 0.041 0.00 6490.
�2013 D. R. STR�NG Consulting Engineers Inc. 20 Saddlebrook Div. II '�
Technical Information Report Renton,Washington I
1.65 490.00 9657. 0.222 0.043 0.00 6626.
1.79 490.14 10594. 0.243 0.045 0.00 6763.
1. 93 490.28 11550. 0.265 0.047 0.00 6902.
. 2.07 490.42 12526. 0.288 0.048 0.00 7042.
2.21 490.56 13522. 0.310 0.050 0.00 7184 .
2.35 490.70 14538. 0.334 0.052 0.00 7327 .
2.49 490.84 15574. 0.358 0.053 0.00 7471.
2.63 490.98 16630. 0.382 0.055 0.00 7617.
2.77 491.12 17707. 0.406 0.056 0.00 7765.
2. 91 491.26 18804. 0.432 0.057 0.00 7913.
3.05 491.40 19923. 0.457 0.059 0.00 8064 .
3.19 991.54 21062. 0.484 0.060 0.00 8215.
3.33 991.68 22223. 0.510 0.061 0.00 8368.
3.47 491.82 23405. 0.537 0.063 0.00 8523.
3.61 491.96 24609. 0.565 0.064 0.00 8678.
3.75 492.10 2583�. 0.593 0.065 0.00 8836.
3.89 492.24 27083. 0.622 0.066 0.00 8994.
4.03 492.38 28354. 0.651 0.068 0.00 9159 .
4.17 492.52 29647. 0.681 0.069 0.00 9316.
4.31 492.66 30962. 0.711 0.070 0.00 9479.
4.45 492.80 32301. 0.742 0.071 0.00 9643.
4.59 492.94 33662. 0.773 0.072 0.00 9808.
4.73 493.08 35047. 0.805 0.073 0.00 9976.
4.87 493.22 36455. 0.837 0.074 0.00 10144 .
4.95 493.30 37271. 0.856 0.075 0.00 10241.
4 .97 493.32 37476. 0.860 0.076 0.00 10265. '
4 . 99 493.34 37681. 0.865 0.080 0.00 10290.
5.02 493.37 37991. 0.872 0.086 0.00 10326.
5.04 493.39 38197. 0.877 0.094 0.00 10351.
5.06 493.41 38405. 0.882 0.105 0.00 10375.
5.08 493.43 38612. 0.886 0.117 0.00 10399.
5.11 493.46 38925. 0.894 0.125 0.00 10436.
5.13 493.48 39134. 0.898 0.129 0.00 10461.
5.27 493.62 40610. 0. 932 0.148 0.00 10633.
5.41 493.76 42111. 0. 967 0.163 0.00 10807.
5.55 493.90 43637. 1.002 0.176 0.00 10983.
5. 69 494.04 45186. 1.037 0.188 0.00 11159.
5.83 494.18 46761. 1.073 0.198 0.00 11338.
5.97 494.32 48361. 1. 110 0.208 0.00 11517.
6.11 494.46 49986. 1. 148 0.218 0.00 11698.
6.25 494. 60 51637. 1.185 0.226 0.00 11881.
6.37 494.72 53072. 1.218 0.234 0.00 12038 .
6.40 494.75 53433. 1.227 0.237 0.00 12078.
6.42 494.77 53675. 1.232 0.243 0.00 12104.
6.45 494.80 54039. 1.241 0.253 0.00 12144 .
6.48 494.83 54404. 1.249 0.266 0.00 12183.
6.50 494.85 54648. 1.255 0.281 0.00 12210.
6.53 494.88 55015. 1.263 0.300 0.00 12250.
6.56 494.91 55383. 1.271 0.320 0.00 12289.
6.58 494.93 55629. 1.277 0.326 0.00 12316.
6.61 494.96 55999. 1.286 0.333 0.00 12356.
6.75 495.10 57742. 1.326 0.362 0.00 12544.
6.89 495.24 59511. 1.366 0.388 0.00 12732.
7.03 495.38 61307. 1.407 0.411 0.00 12923.
O 2013 D. R.STRONG Consulting Engineers Inc. 21 Saddlebrook Div. II
Technical Information Report Renton,Washington
7. 15 49�. �0 62868. 1.�43 0.430 O.CO 13087 .
7.25 495. 60 6u183. 1.473 0. 906 0.00 13224 .
7.35 495.70 65512. 1.504 1.760 0.00 13363.
7.45 495.80 66856. 1.535 2.870 0.00 13502 .
7.55 495. 90 68213. 1.566 4 .180 0.00 1364� .
7. 65 496.00 69584. 1.597 5. 660 0.00 13782.
7.75 496.10 70969. 1. 629 7.100 0.00 1392�.
7.85 496.20 72369. 1. 661 7.640 0.00 14005.
7. 95 496.30 73782. 1.694 8.140 0.00 1420� .
8.05 496.90 75210. 1.727 8.620 0.00 1435� .
8 . 15 496.50 76653. 1.760 9.060 0.00 14496.
8.25 496. 60 78110. 1.793 9.490 0.00 14640.
8.35 496.70 79581. 1.827 9.900 0.00 1478��.
8.45 496.80 81067. 1.861 10.290 0.00 14932.
8.55 496.90 82567. 1.895 10.660 0.00 15079.
8.65 497.00 84083. 1.930 11.030 0.00 1522� .
8.75 497.10 85613. 1.965 11.380 0.00 1537�.
8.85 497.20 87158. 2.001 11.720 0.00 1552�.
8.95 497.30 88718. 2.037 12.050 0.00 15674 .
9.05 497.40 90293. 2.073 12.370 0. 00 1582�.
Hyd Inflow Outflow Peak Storage
Stage Elev (Cu-Ft) ,__�-�'tl
1 1.89 0.43 7.15 495.50 62870. 1.44.�
2 0.92 0.35 6.69 495.04 56962. 1.3C8
3 1. 11 0.22 6.16 494.51 50523. 1.160
4 0. 92 0.21 6.04 494 .39 49188. 1. 129
5 0. 97 0.15 5.32 493. 67 41150. 0. 945
6 0.57 0.08 4.95 493.30 37295. 0.85'0
7 0.73 0.07 4.27 492.62 30617. 0.703
8 0.76 0.06 3.02 491.37 19659. �. ��1
Hyd R/D Facility Tribu�ary Reservoir PCC Outflc.��
Outflow Inflow Inflow Tar et Ca-_c
9
1 0.43 0.06 ******** 0.45 0.44
2 0.35 0.03 ******** ******* 0.36
3 0.22 0.03 ******** ******* 0.23
4 0.21 0.03 ******** ******* 0.22
5 0. 15 0.03 ******** ******* 0. 16
6 0. 08 0.02 ******** ******* 0.0�
7 0.07 0.02 ******** ******* 0.03
8 0.06 0.02 **��***F ****�*� ^ ^�
�. .�o
----------------------------------
Route Time Series through Facili-,�
Inflow Time Series File:rdir.-sf
Outflow Time Series File:rdoLt
POC Time Series File:dso>>t
Inflow/Outflow Analysis
Peak Inflow Discharge: 1.89 CFS at 6: :10 0=, Jar. 9 ia `'e3r 8
Peak Outflow Discharge: 0.932 CFS at 11 : C0 0� �ar � i-� �'ear 8
Peak Reservoir Stage: 7.15 Ft
Peak Reservoir Elev: 995.50 Ft
O 2013 D. R.STRONG Consulting Engineers Inc. 22 Saddlebrook Div. II
Technical Information Report Renton,Washington
� ____ _
i
Peak Reservoir Storage: 62870. Cu-Ft
. 1.943 Ac-Ft
Add Time Series:bypass.tsf
Peak Suruned Discharge: 0.444 CFS at 11:00 on Jan 9 in Year 8
Point of Compliance File:dsout.tsf
Flow Frequency Analysis
Time Series File:rdout.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis-------
Flo�,r Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) (CFS) (ft) Period
0.353 2 2/09/Ol 20:00 0.432 7.15 1 100.00 0. 990
0.070 7 1/07/02 4:00 0.353 6.70 2 25.00 0.960
0.221 3 3/06/03 22:00 0.221 6.16 3 10.00 0.900
0. 059 8 8/26/04 7:00 0.213 6.09 4 5.00 0.800
0.075 6 1/08/05 5:00 0. 153 5.32 5 3.00 0. 667
0. 153 5 1/19/06 2:00 0.075 4.95 6 2.00 0.500
0.213 4 11/24/06 9:00 0.070 4 .27 7 1.30 0.231
0.432 1 1/09/08 11:00 0.059 3.02 8 1. 10 0. 091
Ccmputed Peaks 0.405 7.00 50.00 0. 980
Flow Frequency Analysis
Time Series File:dsout.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis-------
�-o?�� Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(�FS) (CFS) Period
ii. 361 2 2/09/Ol 20:00 0. 444 1 100.00 0.990
�i.081 7 1/05/02 16:00 0.361 2 25.00 0. 960
i:�, 228 3 3/06/03 21:00 0.228 3 10.00 0. 900
0. 077 8 8/26/04 2:00 0.220 4 5.00 0.800 �
0. 083 6 1/05/05 8:00 0.157 5 3.00 0.667 I�
C!. 157 5 1/19/06 1:00 0.083 6 2.00 0.500
:i.220 4 11/24/06 7:00 0.081 7 1.30 0.231
) . 444 1 1/09/08 11:00 0.077 8 1.10 0.091
��:-.�uted Peaks 0.416 50.00 0.980 ,
F1ow Duration from Time Series File:rdout.tsf
Cs�o=f Count Frequency CDF Exceedence Probability
�FS °s $ o
C�. 005 33549 54.711 59.711 45.289 0.453E+00
0,015 6223 10.148 69.860 35.140 0.351E+00
0.025 5918 9.651 79.511 25.489 0.255E+00
0.035 9748 7.743 82.254 17.746 0.177E+00 I
��.045 9536 7.397 89.651 10.349 0.103E+00
�.055 2455 4.004 93. 655 6.345 0.635E-01
:, .064 2006 3.271 96.926 3.074 0.307E-01
.074 1439 2.347 99.273 0.727 0.727E-02
� . 084 110 0.179 99.452 0.548 0.548E-02
C . 094 23 0.038 99.490 0.510 0.510E-02
0. 104 14 0.023 99.512 0.488 0.488E-02
0. 114 11 0.018 99.530 0.470 0.470E-02
� 2013 D. R.STRONG Consulting Engineers Inc. 23 Saddlebrook Div. II
Technical Information Report Renton,Washington
0. 124 26 0.042 99.573 0.427 0.427E-02
0. 134 29 0.047 99.620 0.380 0.380E-02
0. 144 38 0.062 99.682 0.318 0.318E-02
0. 154 35 0.057 99.739 0.261 0.261E-02
0. 163 19 0.031 99.770 0.230 0.230E-02
0. 173 25 0.041 99.811 0.189 0. 189E-02
0. 183 16 0.026 99.837 0.163 0. 163E-02
U. 193 15 0.029 99.861 0.139 0. 139E-02
�.203 18 0.029 99.891 0.109 0. 109E-02
C.213 19 0.031 99.922 0.078 0.783E-03
C.223 19 0.031 99.953 0.047 0.473E-03
0.233 14 0.023 99.976 0.024 0.245E-03
G.243 2 0.003 99.979 0.021 0.212E-03
G.253 2 0.003 99.982 0.018 0.179E-03
u.263 1 0.002 99.984 0.016 0.163E-03
0.272 0 0.000 99. 984 0.016 0.163E-03 '�
0.282 1 0.002 99.985 0.015 0.147E-03 '
0.292 0 0.000 99.985 0.015 0.147E-03
0. 302 1 0.002 99.987 0.013 0.130E-03
��. 312 1 0.002 99.989 0.011 0.114E-03
��.322 0 0.000 99.989 0.011 0.114E-03
�.332 2 0.003 99.992 0. 008 0.815E-04
�.342 1 0.002 99.993 0.007 0. 652E-04
�:.352 3 0.005 99.998 0.002 0.163E-04
Fl�w Duration from Time Series File:dsout.tsf
Cu�off Count Frequency CDF Exceedence Probability
CFS ° ° ° -
0 o a
C.005 33512 54. 651 54. 651 45.349 0.453E+00
C.015 6220 10.149 64.79� 35.205 0.352E+00
O.C25 5951 9.705 74.499 25.501 0.255E+00
0. 036 4709 7.679 82.179 17.821 0.178E+00
0.046 4486 7.316 89.494 10.506 0.105E+00
0. 056 2578 4.209 93.699 6.301 0.630E-01
0.066 1922 3.139 96.833 3.167 0.317E-01
0. 076 1411 2.301 99.134 0.866 0.866E-02
0. 086 175 0.285 99.419 0.581 0.581E-02
0. 096 36 0.059 99.478 0.522 0.522E-02
0. 106 22 0.036 99.514 0.486 0. 486E-02
0. 117 11 0.018 99.532 0.468 0.468E-02
0. 127 25 0.041 99.573 0.427 0.427E-02
0. 137 26 0.042 99.615 0.385 0.385E-02
0. 147 34 0.055 99.671 0.329 0.329E-02
0. 157 43 0.070 99.741 0.259 0.259E-02
�. 167 19 0.031 99.772 0.228 0.228E-02
,';. 177 24 0.039 99.811 0. 189 0.189E-02
C . 188 16 0.026 99.837 0. 163 0.163E-02
;' . 198 15 0.024 99.861 0.139 0.139E-02
� .208 18 0.029 99.891 0.109 0.109E-02
C .2].8 18 0.029 99. 920 0.080 0.799E-03
C .228 18 0.029 99. 949 0.051 0.506E-03
G.238 14 0.023 99. 972 0.028 0.277E-03
0.248 3 0.005 99. 977 0.023 0.228E-03
0.258 2 0.003 99. 980 0.020 0.196E-O:s
s 2013 D. R.STRONG Consulting Engineers Inc. 24 Saddlebrook Div. I!
Technical Information Report Renton,Washingtor
0.269 2 0.003 99.984 0.016 0.163E-03
0.279 0 0.000 99. 984 0.016 0.163E-03
0.289 1 0.002 99. 985 0.015 0.147E-03
0.299 0 0.000 99.985 0.015 0.147E-03
0.309 0 0.000 99.985 0.015 0. 147E-03
0.319 2 0.003 99.989 0.011 0. 114E-03
0.329 0 0.000 99.989 0.011 0. 114E-03
0.340 1 0.002 99.990 0.010 0. 978E-04
0.350 3 0.005 99.995 0.005 0.489E-04 ',
0.360 1 0.002 99. 997 0.003 0.326E-04 I
Duration Comparison Anaylsis ��
Base File: predev.tsf i�
New File: dsout.tsf '�
C�a�cLf Jnits: Discharge in CrS '
-----Fraction of Time----- ---------Check of Tolerance-------
�utoff Base New oChange Probability Base New oChange
C.077 � 0.95E-02 0.81E-02 -19 .6 � 0.95E-02 0.077 0.075 -1.8
C.098 I 0. 63E-02 0.52E-02 -18.3 � 0. 63E-02 0.098 0.082 -15.8
Q. 119 I 0.50E-02 0.46E-02 -6.3 � 0.50E-02 0.119 0.104 -12.7
G. 140 � 0.37E-02 0.37E-02 -0.9 I 0.37E-02 0.140 0.139 -0.2
G. 1'ol � 0.29E-02 0.25E-02 -14 .2 � 0.29E-02 0.161 0.154 -4.2
0. 182 � 0.22E-02 0.18E-02 -17.8 I 0.22E-02 0.182 0.169 -6. 9
�i.203 I 0. 15E-02 0.13E-02 -13.3 I 0. 15E-02 0.203 0.194 -4 . 0
�i.224 I O.10E-02 0.65E-03 -36.5 � 0.10E-02 0.224 0.211 -5. 6
'J.245 I 0. 62E-03 0.23E-03 -63.2 � 0. 62E-03 0.245 0.225 -8.0
C.266 I 0.34E-03 0.18E-03 -47 . 6 � 0.34E-03 0.266 0.235 -11.4
C .287 � 0.21E-03 0.15E-03 -30.8 � 0.21E-03 0.287 0.251 -12.2
C.308 � 0.16E-03 0.15E-03 -10.0 � 0.16E-03 0.308 0.285 -7. 5
0.32R I 0. 98E-�4 C.11E-03 16.7 � 0. 98E-04 0.328 0.340 3.4
0. 3=9 C . 15�-�� C .-�'E-0� 200.0 � 0.16E-04 0.349 0.361 3.2
_>1G_s-m�� �osit-�,.. �._�ur�-cr = C.022 cfs ( 6.40)
cccsrr-n:� w� 0.�38 �-� ��� �_�� Base Cata:predev.tsf
��id at , . �rr __s ��=, -re _.�„ Ca�a:��c,_:t. tsi
[�la_=_i-n�am �egati�.-e �._����si���n = Q.C20 c-s ,-18 . =��)
occurring at C.107 cfs or tre Base Data:predev.tsf
an� at 0.087 cfs on the Ne��r Data:dsout.ts=
O 2013 D. R.STRONG Consulting Engineers Inc. 25 Saddlebrook Div. II III
Technical Information Report Renton,Washington I
Peaks Plot
Retum Penod
2 5 10 20 50 100
� rdo�t.pks in Sea-T�c
♦ dsout.pks
o prec'ev Gl:; R
ae
w
coo � °
�� �
o �
10��
• i a oa
0
tA o
LL
U
m
rn
`m
u
N
�
��2 O
103
1 2 5 i0 20 30 40 50 60 70 80 90 95 98 99
Cumulative Probability
Duration Curve
�
0
rdout.dur o
dsout.dur ♦
�� target dur c
M �'�
O \
L
�� ���a„
[n 000 ��_1�'
LL �\
U `
� N �;i\\'
O
� ���
U \\(:1
N �y
Q Y �
�ti
�
I �S1
' ,
o ,��c
00
'�\�
i ��t
._.. �4�-���'�_�._�
�`��
o �_���
� ° � , �
�o� �o' io�' �o-2 �o-' �o'
Prohabili Ezceedence
�i
O 2013 D. R. STRONG Consulting Engineers Inc. 26 Saddlebrook Div. II
Technical Information Report Renton,Washington
FLOW CONTROL PRIMARY OVERFLOW '
Using standard orifice equation to determine stand pipe diameter in control structure
Ref. KCSWDM '09 Figure 5.3.4.H
Q�oo= 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps
Qioo= 4.65 cfs
HMAx= Maximum available head in feet measured from crest of weir
HM,�= 0.75 ft.
D= Riser Diameter
D= �Q�oo/(3.782 * HMAX .5`�0.5
i
D= 1.19 ft. (min. diameter) round up to nearest standard pipe diameter
use D = 18 in. or 1.5 ft.
Calculate actual height above the weir expected during the 100-year peak storm .
H = Actual head above weir achieved with Q�oo
H = (Q�oo/(9.739* D))^0.67
H = 0.47 ft.
JAILHOUSE SECONDARY OVERFLOW
Using standard weir equation to determine length of window opening in control structure
Ref. KCSWDM '09 Figure 5.3.4.E
D= Control structure diameter I
D= 60 in.
Q�oo= 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps
Qioo= 4.65 cfs
HMAx= Head above weir achieved with Q�oo
HM�= 0.47 ft. '�
P= Height of overflow above outlet invert elevation �
P= 7.15 ft.
c= Constant
c= 3.27+0.4*HMAx/P
C= 3.30 ft.
L= Arc length of the jailhouse window as necessary but not to exceed 50% of
the control structure's internal circumference
L= �Q100�1C*HMAX1.5)1�.O.Z*HMAX
1
L= 4.47 ft. (min. length)
C= Control Structure Circumference
C= 16 ft.
Calculate corrected L due to vertical bars in window.
Lad�= adjusted arc length of the jail-house window
Lad�= L+0.083*(L/0.33)
` L 5.60 ft.
I adj=
' O 2013 D.R.STRONG Consulting Engineers Inc. 27 Saddlebrook Div. II
Technical Information Report Renton,Washington
BIRDCAGE EMERGENCY OVERFLOW SPILLWAY
Using sharp crested weir equation to determine stand pipe diameter in control structure
Ref. KCSWDM '09 Figure 5.3.4.E
Q�oo= 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps
Qioo= 4.65 cfs
P= Height of primary overflow above outlet invert elevation
P= 7.62 ft.
D= Control structure diameter
D= 60 in.
L= Control structure circumference
L= 15.71 ft.
C= 3.27+0.4H/P (ft)
use...
Q�oo= 3.27+0.4HlP(L-0.2H)H^1.5
H= Emergency overflow water surface elevation
H= 0.20 ft.
WATER QUALITY TREATMENT (PART E)
The Project is located in the Basic Water Quality (WQ) Treatment area. The Project
will utilize a BayFilter vault meeting Basic Water Quality treatment criteria. See Figure
7 for details.
�
�
��2013 D. R.STRONG Consulting Engineers Inc. 28 Saddlebrook Div. II
Technical Information Report Renton,Washington
FIGURE 7. DETENTION FACILITY DETAILS AND BAYFILTER SIZING
I
'
' �2013 D. R.STRONG Consulting Engineers Inc. 29 Saddlebrook Div. II
Technical Information Report Renton,Washington
SE 1/4 SE OF SECTION 32, TOWNSHIP 23N, RANGE 5E, W.M.
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SECTION A A SECTION B B � �i �
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A-NNNNAA
� BayFilter Sizing
Details
�
ADS Representative: Kell Kokesh
Date: 5/2/2013
Site Informatian
Pro'ect Name Saddlebrook
Cit Seattle
State WA
Draina e Area 5.397 acres
Im ervious Area 2.857 acres
Pervious Area 2.54 acres
%Im ervious 53%
Upstream Detention System
Peak release rate from detention 0.432 cfs
Treatment release rate from detention 0.075 cfs
S stem Confi uration Offline
Detention retreatment credit 60%
WA DOE Approval
General Use Desi nation Yes
A enc re uired%removal 80%
Filter System
Filtration Brand Ba Filter
Cartrid e Hei ht 28 in
Cartrid e Filter Area 43 sf
Maximum Cartrid e Flow Rate 0.7 gpm/sf
5 ecific Flow Rate 30 gpm
Determine Critical Sizing Value
Number of Cartridges Usin Flow Rate 2
SUMMARY
Treatment Flow Rate 0.075 cfs
Cartrid e Flow Rate 30 gpm
Number of Cartrid es 2
SECTION V
CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Per Core Requirement #4 of the KCSWDM, the conveyance system must be analyzed
and designed for existing tributary and developed onsite runoff from the proposed
project. Pipe systems shall be designed to convey the 100-year design storm. The
Rational Method was used to calculate the Q-Ratio for each pipe node.
A conveyance system consisting primarily of pipes and catch basins has been designed
for Saddlebrook Div. I and Div. II. Onsite runoff will be collected by the multiple catch
basins. Pipes are typically twelve- and eighteen-inch diameter LCPE material. The
pipes will have a minimum slope of 0.87%.
The pond primary overflow riser is designed to convey the 100-year peak storm (design
storm), based on the KCRTS 15-minute time series for developed, undetained
conditions on site. This is calculated at 4.65 cfs. The results of the 15-minute KCRTS
time series and KCBW Calculations are included in this Section.
DEVELOPED 15-MINUTE TIME SERIES
Modeling input
Land cover Entire
� Site
Till forest(ac) 0.000
Till Grass (ac) 2.540
Wetland (ac) 0.000
Impervious (ac) 2.857
Scale Factor: 1.00
Time Step: 15-Min
Data Type: Reduced
Project location: Seatac
Total Area: 5.397
Table 5 Developed 15-Min KCRTS Modeling Input
O 2013 D. R.STRONG Consulting Engineers Inc. 30 Saddlebrook Div. II
Technical Information Report Renton,Washington
Modeling results �
Developed 15-Min
Fiow Frequency Ar.a-_ys�s
Time Series File:l5-min-sea.�sf I
Project Location:Sea-Tac ,
---Annual Peak Flow Rates--- -----Flc�a Frequency Analysis------- '
Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS} (CFS) Period
1.36 6 8/27/O1 18:00 4.65 1 100.00 0. 990
1.01 8 1/05/02 15:00 3.13 2 25.00 0.960
3.13 2 12/08/02 17: 15 1.96 3 10.00 0.900
1.10 7 8/23/04 14:30 1.93 4 5.00 0.800
1. 96 4 11/17/04 5:00 1. 69 5 3.00 0.667
1. 69 5 10/27/05 10:45 1.36 6 2.00 0.500
1. 93 3 10/25/06 22:45 1.10 7 1.30 0.231
4 . 65 1 1/09/08 6:30 1.01 8 1.10 0.091
Ccmputed Peaks 4.15 50.00 0.980 i
O 2013 D. R.STRONG Consulting Engineers Inc. 31 Saddlebrook Div. II
Technical Information Report Renton,Washington
BACKWATER ANALYSIS
Storm Water Runoff Variables:
A= Total of Subasin and Tributary Areas
C= Runoff Coefficient(the anticipated proportion of rainfall volume that runs off the area)see 2009 KCSWM Table 3.2.1A
CC= Composite Runoff Coefficient
CC= S(Cn*An)/ATotal
Tc= Time of Concentration(Typically 6.3 minutes which is the minimum value used in calculations)
R= design return frequency
iR= Unit peak rainfall intensity factor
iR= (aR)(Tc)^(-bR)
aR,bR= coefficients from'09 KCSWM Table 3.2.1.B used to adjust the equation for the design storm
IR= Peak rainfall intensity factor for a storm of return frequency'R'
IR= PR'iR
PR= total precipitation(inches)for the 24-hour storm event for the given frequency. See Issopluvial Maps in 2009 KCSWM Figures 3.2.1.A-D
QR= peak flow(cfs)for a storm of return frequency'R'
QR= CC*iR*A
The Q-Ratio describes the ratio of the tributary flow to the main upstream flow.
R= 10D -year storm
aR= 2.61
bR= 0.63
PR=�:�rc�s,+�'1 } 4 inches
.��__
Conveyance System Variables:
d= pipe diameter I
n= Manning's Number
1= length of pipe
- — - - - --- --
v 2013 D. R. STRONG Consulting Engineers Inc 32 Saddlebrook Div. II
Technical Information Report Renton,Washington
Pipe Structures Subasins& A A C CC Tc iR IR QR SQR Q- d Material n I Slope invcrt invert over- Q V Bend CD
Tributaries subasin Ratio in out flow Full Full Dia
elev. Flow Flow
FROM CB To CB sf Ac Ac Min. cfs cfs in ft % ft ft ft cis fps
CB#4 TO INLET 1
4 4 3 4 589 0.01 0.90 6.3 0.82 3.27 0.04 0.04 0.00 12 N-12 0.012 36 1.46 498.50 497.98 501.50 4.68 5.95 0 2
RUN 1033 39482 0.91 0.63
3 3 2 3 36336 D.83 0.61
3 3 2 3 75818 1.74 0.62 6.3 0.82 3.27 3.54 3.58 88.91 12 N-12 0.012 222 0.87 497.98 496.05 501.22 3.61 4.60 0.2 2 I
RUN 102-2 21239 0.49 0.58
2 2 1 2 30748 0.71 0.57
2 2 1 2 51987 1.19 0.58 6.3 0.82 3.27 2.25 5.83 0.63 18 N-12 0.012 299 1.10 495.55 492.27 505.93 11.95 6.76 0.2 4
RUN 101-1 1006 0.02 0.90
RUN 703-1 81331 1.87 0.59
1 1 INLET 1 1 5477 0.13 0.90
1 1 INLET 1 1 87814 2.02 0.61 6.3 0.82 3.27 4.06 9.89 0.70 18 N-12 0.012 63 6.25 492.27 486.35 499.73 28.52 16.14 124.59 4
CB#703 TO CB#1
703 703 702 703 36095 0.83 0.51 6.3 0.82 3.27 1.38 1.38 0.00 12 N-12 0.012 77 3.88 502.61 499.63 507.61 7.62 9.70 0 2
702 702 701 702 4210 0.10 0.90 6.3 0.82 3.27 0.28 1.66 0.21 12 N-12 0.012 122 3.51 499.63 495.35 502.63 7.25 9.23 88.23 2
701 701 7 701 4217 0.10 0.90 6.3 0.82 3.27 0.29 1.95 0.17 12 N-12 0.012 23 1.00 495.35 495.12 498.50 3.87 4.92 18.74 2
7 7 5 7 735 0.02 0.90 6.3 0.82 3.27 0.05 2.00 0.03 12 N-12 0.012 31 2.28 495.12 494.42 498.12 5.84 7.44 44.11 2
5 5 1 5 36074 0.83 0.60 6.3 0.82 3.27 1.62 3.62 0.81 12 N-12 0.012 25 6.73 494.42 492.77 499.42 10.04 12.78 57.44 2
81331 1.87 0.59
CB#101 TO CB#1
101 101 1 101 1006 0.02 0.90 6.3 0.82 3.27 0.07 0.07 0.00 12 N-12 0.012 21 0.98 492.98 492.77 497.86 3.83 4.88 0 2
CB#102 TO CB#2
102 102 2 102 21239 0.49 0.58 6.3 0.82 327 0.93 0.93 0.00 12 N-12 0.012 24 20.05 500.93 496.05 505.93 17.33 22.06 0 2 i
CB#'103 TO CB#3
103 103 3 103 394�2 0.91 D.63 6.3 0.82 3.27 1.86 1.88 0.00 12 N-12 0.012 24 0.99 49822 497.98 50122 3.II4 4.89 0 2
c�)2013 D. R. STRONG Consulting Engineers Inc. 33 Saddlebrook Div. II
Technical Information Report Renton,Washington
--�
BACKWATER ANALYSIS MAP '
O 2013 D. R.STRONG Consulting Engineers Inc. 34 Saddlebrook Div. II
Technicai Information Report Renton,Washington ',
�
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1 I
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4,217 S.F. LOT 5 Z
i 30,538 S.F. LOT 102 ; '
y I 18,801 SF. 29�92 S.F. � Q i
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Q i - Y
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� 28,311 S.F. LOT 3 � � y
I29,539 S.F. �
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' � III
NORTH I
DRAFTcD BY.� YLp
GRAPHIC SCALE G£SfCN£D BY. YLP
O 3O V O 9O PROJECT ENGIN£ER: MAJ
� � OATE: 04.30.13 �.
PR0.AECT NO.: 13030 '
1 INCH = 60 FT.
GRAW/NG: �
R:�2G12�,.ri'�12040�31DrawC-cs�Base\39V✓72G40.dwg 5/3/2C7..' 3:55:lE A.4! FDT I,
COPIRIGHT Q 2012, D.R. STRONG CO��SULTIN3 ENG!�VEERS �,VC. SHEET.� � OF � j
BACKWATER ANALYSIS RESULTS
BACKWATER COMPUTER PROGRAM FOR PIPES
Pipe data from file:CB#4 TO INLET l .bwp
Surcharge condition at internediate junctions
Tailwater Elevation:494.51 feet
Discharge Range:0.985 to 9.89 Step of 0.9�5 [c�s]
Overflow Elevation:501.5 feet
Weir:NONE
Upstream Velocity:0. feet/sec
PI2E NO. 1: 62 LF - 18��cP @ 6.250 oUrLET: 488.35 IULET: 492.27 INTYP: 5
JUNC N0. 1: OVERFLOW-EL: 499.73 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.70
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI
�********************�*�*�*�**�**********************************************�,�
0.99 2.26 499.53 * 0.012 0.38 0.20 6.16 6.16 2.25 2.26 0.46
1.97 2.29 494.56 * 0.012 0.53 0.27 6.16 6.16 2.26 2.29 0.6°
2.95 2.36 494.63 * 0.012 0.66 0.33 6.16 6.16 2.28 2.36 0.8��
3.94 2.45 494.72 * 0.012 0.76 0.38 6.16 6.16 2.32 2.45 1.G°
4.93 2.57 494.84 * 0.012 0.86 0.43 6.16 6.16 2.36 2.57 1.2c
5.91 2.72 494.99 * 0.012 0.94 0.47 6.16 6.16 2.41 2.72 1.4�
6.90 2.89 495.16 * 0.012 1.02 0.51 6.16 6.16 2.47 2.89 l.0'4
7.88 3.09 495.36 * 0.012 1.09 0.54 6.16 6.16 2.54 3.09 1.83
8.87 3.31 495.58 * 0.012 1.16 0.58 6.16 6.16 2.62 3.31 2.OF
9.85 3.56 495.83 * 0.012 1.22 0.61 6.16 6.16 2.71 3.56 2.32
10.84 3.84 496.11 * 0.012 1.27 0.65 6.16 6.16 2.81 3.84 2.61
PIPE NO. 2: 299 LF - 18"CP @ 1.10$ OUTLET: 492.27 INLET: 495.55 INTYP: 5
JUNC N0. 2: OVERFLOW-EL: 505.93 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.63
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HW_T
************************+�*************************x*****+**�****************��
0.58 0.37 495.92 * 0.012 0.29 0.23 2.26 2.26 0.29 ***** 0.3;
1.16 0.54 496.09 * 0.012 0.41 0.32 2.29 2.29 0.41 ***** 0.54
1.74 0.66 496.21 * 0.012 0.50 0.39 2.36 2.36 0.50 ***** 0.65
2.32 0.77 496.32 * 0.012 0.58 0.45 2.45 2.45 0.58 ***** 0.7?
2.90 0.87 496.42 * 0.012 0.65 0.51 2.57 2.57 0.65 ***** 0.8?
3.49 0.95 496.50 * 0.012 0.72 0.56 2.72 2.72 0.72 ***** 0.95
4.07 1.03 496.58 * 0.012 0.78 0.61 2.89 2.89 0.78 ***** 1.C3
4.65 1.10 496.65 * 0.012 0.83 0.66 3.09 3.09 0.83 ***** 1.10
5.23 1.17 496.72 * 0.012 0.89 0.70 3.31 3.31 0.89 ***** 1.1?
5.81 1.32 496.87 * 0.012 0.94 0.74 3.56 3.56 1.08 1.32 1.24
6.39 1.53 497.08 * 0.012 0.98 0.79 3.84 3.84 1.44 1.53 1.30
PIPE NO. 3: 221 LF - 12"CP @ 0.87$ OUTLET: 496.05 INLET: 497.98 INTYP: 5
JUNC NO. 3: OVERFLOW-EL: 501.22 BEND: 0 DEG DIA/WIDTH: 2.0 Q-RATI0:88.91
Q(CFS) HW(FT) HW ELEV. * N-rAC DC DN TW DO DE HWO HWI
*���*******************************************************�******************�
0.36 0.33 498.31 * 0.012 0.25 0.22 0.00 0.22 0.25 ***** 0.3�
0.71 0.49 498.47 * 0.012 0.36 0.31 0.04 0.31 0.36 ***** O.�y
1.07 0.61 498.59 * 0.012 0.44 0.38 0.16 0.38 0.44 ***** 0.61
1.43 0.73 498.71 * 0.a12 0.51 0.44 0.27 0.44 0.51 ***** 0.73
1.78 0.85 498.83 * 0.012 0.57 0.50 0.37 0.50 0.57 ***** 0.8�
2.14 0. 96 498.94 * 0.012 0.63 0.56 0.45 0.56 0.63 ***** 0.9,�
2.50 1.07 499.05 * 0.012 0.68 0.62 0.53 0.62 0.68 ***** 1.07
2.85 1.19 499.17 * 0.012 0.73 0.68 0.60 0.68 0.73 ***** 1.1°
3.21 1.33 499.31 * 0.012 0.77 0.74 0.67 0.74 0.77 ***** 1.33
3.57 1.49 499.47 * 0.012 0.81 0.82 0.82 0.82 0.82 1.44 1.49
3.92 1.97 499.95 * 0.012 0.85 1.00 1.03 1.03 1.39 1.97 1.65
O 2013 D. R.STRONG Consulting Engineers Inc. 35 Saddlebrook Div. II
Technical Information Report Renton,Washington
PIPE NO. 4: 35 LF - 12"CP @ 1.46% OUILET: 497.98 INL�T: 498.50 INiYP: 5
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI
***************�**************************************************************�
0.00 0.04 498.54 * 0.012 0.03 0.03 0.33 0.33 0.03 0.04 O.u3
0.01 0.06 498.56 * 0.012 0.04 0.09 0.49 0.49 0.05 0.06 0.04
0.01 0.10 498.60 * 0.012 0.05 0.04 0.61 0.61 0.10 0.10 0.0�
0.02 0.22 498.72 * 0.012 0.06 0.05 0.73 0.73 0.22 0.22 O.Oo
0.02 0.33 498.83 * 0.012 0.06 0.05 0.85 0.85 0.33 0.33 0.07
0.02 0.45 498.95 * 0.012 0.07 0.06 0.96 0.96 0.45 0.45 0.08
0.03 0.56 499.06 * 0.012 0.07 0.06 1.07 1.07 0.56 0.56 0.08
0.03 0.68 499.18 * 0.012 0.08 0.06 1.19 1.19 0.68 0.68 0.09
0.04 0.82 499.32 * 0.012 0.08 0.07 1.33 1.33 0.82 0.82 0.10
0.04 0.97 499.47 * 0.012 0.09 0.07 1.49 1.49 0.97 0.97 0.10
0.04 1.46 499.96 * 0.012 0.09 0.07 1.97 1.97 1.46 1.46 0.11
BACKWATER COMPUTER PROGRAM FOR PIPES
Pipe data from file:CB#703 TO CB#l .bwp
Surcharge condition at intermediate junctic:s
Tailwater Elevation:495.84 feet
Discharge Range:1.38 to 3.62 Srep o� C.�_: ;�f.s-
Overflow Elevation:507.61 feet
Weir:NONE
Upstream Velocity:0. feet/sec
PIPE N0. l: 24 LF - 12"CP @ 6.73� CII�L�:: 4y�.17 I:dL�i: 4y=.42 I2diYP: 5
JUNC NO. 1: OVERFLOW-EL: 499.42 BEND: 57 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.81
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI
***************************�****************x***********+�********************�
1.38 1.53 495.95 * 0.012 0.50 0.26 3.07 3.07 1.46 1.53 0.69
1.60 1.56 495.98 * 0.012 0.54 0.28 3.07 3.07 1.46 1.56 0.7�
1.83 1.60 496.02 * 0.012 0.58 0.29 3.07 3.07 1.47 1.60 0.83
2.05 1.65 496.07 * 0.012 0.62 0.31 3.07 3.07 1.49 1.65 0.9_
2.28 1.70 496.12 * 0.012 0.65 0.33 3.07 3.07 1.51 1.70 0.98
2.50 1.76 496.18 * 0.012 0.68 0.35 3.07 3.07 1.52 1.76 1.0�
2.72 1.83 496.25 * 0.012 0.71 0.36 3.07 3.07 1.54 1.83 1.12
2.95 1.90 496.32 * 0.012 0.74 0.38 3.07 3.07 1.56 1.90 1.20
3.17 1.97 496.39 * 0.012 0.77 0.39 3.07 3.07 1.59 1.97 1.2:
3.40 2.05 496.47 * 0.012 0.79 0.41 3.07 3.07 1.61 2.05 1.3�
3.62 2.14 496.56 * 0.012 0.82 0.42 3.07 3.07 1.64 2.14 1.4°
PIPE NO. 2: 30 LF - 12"CP @ 2.28s OUTLET: 494.42 INLET: 495.12 INTYP: �
JUNC N0. 2: OVERFLOW-EL: 498.12 BEND: 44 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.03
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI
*�********�****************+�*****************************�*�****************�_�
0.76 0.87 495.99 * 0.012 0.37 0.25 1.53 1.53 0.85 0.87 0.49
0.89 0.90 496.02 * 0.012 0.40 0.27 1.56 1.56 0.88 0.90 0.53
1.01 0.96 496.08 * 0.012 0.43 0.29 1.60 1.60 0.93 0.96 0.�7
1.13 1.01 496.13 * 0.012 0.45 0.30 1.65 1.65 0.98 1.01 0.61
1.26 1.08 496.20 * 0.012 0.48 0.32 1.70 1.70 1.04 1.08 0.6�
1.38 1.15 496.27 * 0.012 0.50 0.34 1.76 1.76 1.10 1.15 0.68
1.50 1.23 496.35 * 0.012 0.53 0.35 1.83 1.83 1.17 1.23 0.72
1.63 1.31 496.93 * 0.012 0.55 0.37 1.90 1.90 1.25 1.31 0.7�
1.75 1.41 496.53 * 0.012 0.57 0.38 1.97 1.97 1.33 1.41 0.7�
1.88 1.51 496.63 * 0.012 0.59 �0.40 2.05 2.05 1.42 1.51 0. ��
2.00 1.61 490.73 * 0.012 0. 61 0.41 2.14 2.14 1.52 1.61 0.85
�2013 D.R.STRONG Consulting Engineers Inc. 36 Saddlebrook Div. II
Technical Information Report Renton,Washington
PIPE �O. 3: 23 LF - '_2"C? @ 1.00% OUTLEi: 495.12 INLEi: 49�.35 INTYP: 5
JUNC NO. 3: OVERFLOW-EL: 498.50 BEND: 18 DEG DIA/WIDTH: 2.0 Q-RATIO: 0. 17
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI
*x*x�*********���**�*+*�********��*******************�************�*****�*****�
0.74 0.68 496.03 * 0.012 0.37 0.30 0.87 0.87 0.64 0.68 O.S9
0.86 0.72 496.07 * 0.012 0.39 0.33 0.90 0.90 0.68 0.72 0.53
0.98 0.78 496.13 * 0.012 0.42 0.35 0.96 0.96 0.73 0.78 0.5?
l.11 0.84 496.19 * 0.012 0.45 0.37 1.01 1.01 0.79 0.84 0.6"_
1.23 0.92 496.27 * 0.012 0.47 0.39 1.08 1.08 0.87 0.92 0.6�
1.35 0.99 496.34 * 0.012 0.50 0.41 1.15 1.15 0.94 0.99 0.6�
1.47 1.08 496.43 * 0.012 0.52 0.93 1.23 1.23 1.03 1.08 0.72
1.59 1.18 496.53 * 0.012 0.54 0.45 1.31 1.31 1.12 1.18 0.75
1.71 1.29 496.64 * 0.012 0.56 0.47 1.41 1.41 1.22 1.29 0.78 i
"_.83 1.41 490.76 * 0.012 0.58 0.49 1.51 1.51 1.33 1.41 0.81
1.95 1.53 496.88 * 0.012 0.60 0.51 1.61 1.61 1.49 1.53 0.85
FIF� NO. 4: 121 LF - 12"CP @ 3.510 OUTLET: 495.35 INLET: 499.63 INTYP: 5 I
JJP1C NO. 4: OVERFLOW-EL: 502.63 BEND: 88 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.21
Q(CFS) HW(FT) HW ELEV. * N-rAC DC DN TW DO DE HWO HWI '
t�,rxxxx****x***********�******x**********************�************************* ..
C. 63 0.44 500.07 * 0.012 0.34 0.21 0.68 0.68 0.34 ***** 0.44
C.74 0.49 500.12 * 0.012 0.36 0.22 0.72 0.72 0.36 ***** 0.49
C.84 0.53 500.16 * 0.012 0.39 0.24 0.78 0.78 0.39 ***** 0.53
0,94 0.56 500.19 * 0.012 0.41 0.25 0.84 0.84 0.41 ***** 0.56
"-.05 0.60 500.23 * 0.012 0.44 0.26 0.92 0.92 0.44 ***** 0.60
1.15 0.64 500.27 * 0.012 0.46 0.27 0.99 0.99 0.46 ***** 0.64
1.25 0.67 500.30 * 0.012 0.48 0.29 1.08 1.08 0.48 ***** 0.67 '
1.36 0.71 500.34 * 0.012 0.50 0.30 1.18 1.18 0.50 ***** 0.71
1.46 0.75 500.38 * 0.012 0.52 0.31 1.29 1.29 0.52 ***** 0.75
1.56 0.78 500.41 * 0.012 0.54 0.32 1.41 1.41 0.54 ***** 0.78
1.66 0.82 500.45 * 0.012 0.55 0.33 1.53 1.53 0.55 ***** 0.82
PIPE N0. 5: 76 LF - 12"CP @ 3.88$ OUTLET: 499.63 INLET: 502.61 INTYP: 5
4(C�S) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI
k**********�******************�****************+*******�*******************�***
G.53 0.40 503.01 * 0.012 0.31 0.18 0.44 0.44 0.31 ***** 0.40
G.61 0.43 503.04 * 0.012 0.33 0.20 0.99 0.49 0.33 ***** 0.43
G.70 0.46 503.07 * 0.012 0.35 0.21 0.53 0.53 0.35 ***** 0.46
G.78 0.50 503.11 * 0.012 0.37 0.22 0.56 0.56 0.37 ***** 0.50
��.87 0.53 503.14 * 0.012 0.40 0.23 0.60 0.60 0.40 ***** 0.53
�.95 0.56 503.17 * 0.012 0.41 0.24 0.64 0.64 0.41 ***** 0.56
1.04 0.59 503.20 * 0.012 0.43 0.25 0.67 0.67 0.43 ***** 0.59
1.12 0.62 503.23 * 0.012 0.45 0.26 0.71 0.71 0.45 ***** 0.62 ',
1.21 0.65 503.26 * 0.012 0.47 0.27 0.75 0.75 0.47 ***** 0.65
1.29 0.68 503.29 * 0.012 0.49 0.28 0.78 0.78 0.49 ***** 0.68
�.38 0.70 503.31 * 0.012 0.50 0.29 0.82 0.82 0.50 ***** 0.70
�2013 D. R. STRONG Consulting Engineers Inc. 37 Saddlebrook Div. II ,
Technical Information Report Renton,Washington
BACKWATER COMPUTER PROGRAM FOR PIPES
Pipe data from file:CB#101 TO CB#l .bwp
Surcnarge condition at intermediate junctions
Tailwater Elevation:495.84 ieet
Discharge Range:0.07 to 0.07 Step of 0.07 [cfsj
Overflow Elevation:497.86 feet
Weir:NONE �
Upstream Velocity:0. feet/sec
PIPE NO. 1: 21 LF - 12"CP @ 0.98� CCi_�'�': -�2.77 I�dL�T: =92.98 _I•I1`�P: 5
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HTn�I
***��*�***********�*�***************�***x***x�*************x***********�*x*�***
0.07 2.87 495.85 * 0.012 0.11 0.10 3.07 3.07 2.87 2.87 0.14
BACKWATER COMPUTER PROGRAM FOR PIPES
Pipe data from file:CB#102 TO CB#2 .bwp
Surcharge condition at intermediate junctions
Tail�aater Elevation:496.87 feet
Discharge Range:0.93 to 0.93 Ste� of 0.93 [cfs]
Overflow Elevation:505.93 fee�
Weir:NONE
Upstream Velocity:0. feet/sec
_ rI�E NO. l: 24 LF - 12"CP @ 20.05°s 0[JTLET: 496.C5 I'dLEi: SC�G.93 iidTY�: 5
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI
****x******��*******�***�****x*�*�*******x�*******************�***************x
0.93 0.97 50'_.40 * 0.012 0.41 0.?6 0.82 0.82 0.4= ***** C.47
BACKWATER COMPUTER PROGRAM FOR PIPES
� Pipe data from file:CB#103 TO CB#3 .bwp
Surcharge condition at intermediate junctions
Tailwater Elevation:499.47 feet
Discharge Range:1.88 to 1.B8 St�U of =.88 [cis]
Overflow Elevation:501.22 fee�
Weir:NONE
Upstream Velocity:0. feet/sec
PIPE N0. 1: 24 Lr - 12"CP @ 0.99� OUTLET: 497.98 I`dLEi: �98.22 =tdl'YP: �
Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HGdI
**�*�*��*******x+*�**x***x*�**�*x*�xx*****�*****�xx**x****��x*xx***�*x*xxx�*�xx
-. E� "-.44 49�.65 t 0.0"2 0.�'? O.�C 1. �9 "-.4° 1.3_ 1.44 0.88
O 2013 D.R.STRONG Consulting Engineers Inc. 38 Saddlebrook Div. 11
Technical Information Report Renton,Washington
I �
- --,
SECTION VI �
SPECIAL REPORTS AND STUDIES I
The following report and studies have been provided with this submittal.
1. Geotechnical Engineering Study— Earth Solutions NW, LLC, August 21, 2012
2. Saddlebrook Phase II — Earth Solutions NW, LLC, May 15, 2013 ii
3. Tree Inspection Report— Greenforest, Inc., May 1, 2013 I
O 2013 D. R.STRONG Consulting Engineers Inc. 39 Saddlebrook Div. II
Technical Information Report Renton,Washington ,
�
SECTION VII
OTHER PERMITS, VARIANCES AND ADJUSTMENTS '
Approved Drainage Adjustment 2012-03 (Attached)
Approved ADS BayFilter Adjustment 2012-04 (Attached) ii
s 2013 D. R.STRONG Consulting Engineers Inc. 40 Saddlebrook Div. II
Technical Information Report Renton,Washington
PUBLIC WORKS DEPARTMENT � ^c��rof�O� .�;_:
�� a�`�:
. IVI E M O R A N D U M .
. DATE: August 16, 2012
TO: Arneta Henninger, Plan Revie�ver
FROM: ���—Rnn Straka,Surface Water Utility Supervisor, x7248
STAFF CONTACT: Hebe Bernardo,Surface Water Utility Engineer,x7264
SUBIECT: Sac�dlebrook PIat Adjustment 2012-Q3
The City of Renton Surface Water Utility has completed review of the adjustment .
request for the Saddlebrook P(at in accordance with �ty adopted 2009 King County
Surface Water Design Manual (KCSWDM) anci City Amendments to the 2009 KCSWDM.
Our review of the information leads us to understand that the applicant's engineering is
� requesting an adjustment frorr� the 2009 King County Surface Water Design Manual to �
core requirement#1 (section 1.2.1), Qischarge at the Natural Location. Our review of �
the information provided by the applicant engineer on August 13, 2012, provides the �
following findings: p�
�
1. The proposed project has not cornpleted the process preliminary plat approval �
or SEPA review. L j
2. The site is {ocated in two existing parcefs (3664500Z60 and 3664540261) with a
total area of 4.36 acers. Parcels are situated a#op a ridge and discharges
runoff into two subbasins. Tributary Drainage Area (TDA)�West is
approximately 1.78 acres and discharges ta 156th Avenue SE while TDA East is
comprisec{ of the remaining 2.58 acres and discharges to 158th Avenue SE.
The discharge elevation of TDA West is approximately six feet lower than that of
TDA East. These two flowpaths converge at a point approximately 3,000 feet
downstream of TDA West and 4,900 feet downstream of TDA East at the
corner of 156th Avenue SE and SE 144th Street (convergence point).
3. The proposal is to collect much of the runoff from the project site (4.36 acres)
and direct it to a single combined detention and water quality facility located in
the west portion of the site. The allowed release would then discharge through
an existing conveyance system into the right-of-way of 156th Avenue SE where it
continues to go south and canverges with TDA East.in SE 144th Street.
1an I(lian '
Page 2 of 4
August i6,2012 '
4. No downstream analysis has been campleted and submitted to the City for
review. However, a pr�liminaryfield recognizance ofthe downstream drainage
� system was completed bythe applicant and applicant's engineer. Findings were
� discussed in the adjustment letter. Preliminary analysis demonstrafed that the
downstream path from TDA WeSt is mostly comprised of a constructed
conveyance system from the�site to the convergence point. This conveyan.ce
system is made up of grass and rock-lined ditches as wel( as culverts, pipes,
and catch basins. •
5. King County drainage complaints in the area were reviewed and the basin
draining to the conveyance system was determined using King County
iMAP. This resource review revealed an overall basin size of approximately
73.5 acres and no relevant drainage complaints in the last 15 years
downstream of the Site.
6. To analyze the impact of the discharge rate, the King County Runoff Time
Series Software was used to examine.the overall site in a forested condition, �
TDA West's existing conditian, and the 73.5 acre basin in a forested condition as
well as a full build-out condition (undetained, �based on KCSWDM Table
� 3.2.2.0 for 4.0 DU/GA, 42% impervious). TDA West (in its existing condition}
generates approximately 0.29 cfs of runoff for the 100-year return interval.
The total site, when analyzed for the forested condition, will generate
approximately 0.35 cfs of runoff for the 100-year return interval. The existing
canveyance system downstream of the proposed plat would receive a net
increase in runofF of 0.06 cfs,which is less than 0.1 cfs. The total drainage
basin currently generates 5.93 cfs and 23.59 cfs, for forested and build-out
conditions assuming no flow control, respectivefy.
Based on these understandings,findings, and per section 1.2.1 of the 2009 Surface I',
Water Design Manual as amended by the City,the adjustment to allow the diversion of ��
runoff to a single combined stormwater flovv control and water quafity treatment facility lil
drainingto SE 156th Avenue is approved with the following conditions: ',
1. A level flne downstream analysis in accordance with section 1.2.1 of the 20D9
KCSWDM a5 amended by the City shall be submitted to the City for review.
Based on this analysis, the City may require the completion of a downstream
analysis and/or impro�ements to the downstream system.
H:\File Sys\SWP-Suriace Water Projects\SWP-27-Sur;ace Water Projects{CI?)\27-3129 Renton Stormwater
Ma nu al\ADJ USTMENTS\2012\2012-3 5a ddlebrook.doc\H Bah
Jan Illian
Page 3 of 4
. August 16,2012
2. The proposed combined detention and water quality treatment facility to be
constructed on the northwest corner of the site shall be designed as a level 3
flow control for the entire site in using the two basins as the existing (forested)
site conditions. The stormwater facility shalf be designed in accordance with
� section 1.2.3 ofthe 2009 KCSWDM. �
3. Surface water discharge from the west basin is required to follow its existing
drainage course.
4. Water quality treatment in accordance with�section 1.2.8 of the 2009 KCSWDM
shall be provided for all targeted surfaces prior to discharging from the site. The
water quality facility shall be sized based on the entire proposed subdivision
draining to the facility including any required frontage improvements.
5. The refease rate from the detention facility will be based on afl of the tributary
area being directed to the faciiity.
6. The volume of the stormwater detention facility shall be based on all flows
directed to the facifity at full development under current zoning. The detention
volume shall be sized using Level 3 Flood Problem Flow Control Standards in the
2009 KCSWDM. The pre-developed condition runoff rates for the sizing of the
facility shall be based on the entire site using forested as pre-developed s�te
conditions. The TIR shall include all required documentation detailed in chapter
2 of the 2009 KCSWDM for the sizing of the facility.
7. Additionaf storm drainage requirements identified by the City of Renton as part
of the SEPA review process or preliminary plat approval may apply to this
project. Please note that the approval of this adjustment does nof relieve the
� applicant from other conditions that may be stipulated in future city, state, or
federal permits/requirements. �
Motes to applicant:
1. All lots within the Saddlebrook Plat are required to provide flotv control SMPs in
accordance with figure C.1.3.A of the 2009 KCSWDM. Flow control BMP credits
in accordance with section 1.2.3 ofthe 2005 KCSWDM may be used to reduce
the size ofthe required flow control facility. The feasibilityto implement full
dispersion BMPs and full infiltration BMPs shall be verified first. If
� implementation of full dispersion BMPs and full infiltration BMPS are not
feasible alternatives,then any of the BMPs listed in figure C.1.3.A shall be
provided. The selected f{ow control BMP to be implemented on each lot shall be
shown on the co.nstruction plans. Drainage calculations for the sizing of the
. � proposecJ BMPs to be constructed on each lot shall be included in the TIR. II
H:\Fle Sys\SWP-Surface Water Projects\SWP-27-Surface Water Projects(CIP)\27-3129 Renton Stormwater
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Jan Illian
Page 4 of 4
August 16,Z012
Construction of the proposed flow control BMPs may be differed for
construction on the lot at time of building permit.
It�you have any questions about this adjustment, please contacE Hebe Bernardo or me.
Attachmens
cc: Lys Hornsby,P.E.,Utility Systems Director
� Kayren Kittrick,Development Engineering Supervisor
i Vanessa Dolbee,Planner
File
H:\File Sys\5WP-Surface Water Projects\SVJP-27-Surr`ace VJater Projecs(QP)\27-31Z9 Renton 5tormwater
Nlanua(\ADJUSTMENTS\2012\2012-3 Saddlebrook.doc\HBah
QUBLIC WORKS DEPARTMENT D o c�yof .,,.,� I
���0� ���' i
M E � M O R A IV D U M �
DATE: October 31, 2012 .
TO: . Arneta Henninger, Plan Reviewer
FROM: ��2 Ron Straka, Surface Water Utility Supervisor,x7248
STAFF CONTACT: Hebe C. Bernardo, Surface Water Utility Engineer,x7248
SUBJECT: Saddlebrook Plat—ADS BayFilterTM Adjustment 2012-04
The City of Renton Surface Water Utiiity has completed re�iew of the adjustment request from
DR Strong Consultant Engineer for the Saddlebrook Plat in accordance with City adopted 2009
King County�Surface Water Design Manual (KCSWDM}and Ciiy Amendments to the 2009
KCSWDM. Our review of the infiormation leads us to understand that the applicant's
engineering is requesting an adjustment from the 2009 King County Surface Water Design
Manual.to core requirement#8),Water Quality. Our review of the information provided by the
applicant engineer on October 16,2012, prbvides the following�ndings:
1. The proposed project has not completed the process preliminary plat approval orSEPA
review. .
2. The site is located in two existing parcels(3664500260 and 3664500261)with a toial
area oT4.36 ac�es. P�rcei� arN si��ia�e� atop a riclge a��d uischarges iun�ff i��o �wo
� sub-basins. An adjustment to Core Requirement#1, Discharge at the Natural Location
was approved in December 11,2012 allowing the project to collect much of the runoff
from i5e projEci site(4.36 acres) and direct it to a single combi�ed �etent�o� and water
. quality facility located in the v�Jest portion oi the site.
The adjustmeni requesi pioposes io use i ie BayF'tlierT"^ Sys�em for Easic Water Quality
� treatment. The L1/ashington Stat�Dzpartment of Ecolog�r has approved the BayFilterT"'System
� for General Use Level Designa�ion for Basic Water Quality treatment. �
Based on the information provided in the adjustment request;the BayFifterTM'System for Basic .
Water Quality Treatment is approved with the following conditions: �
� 1. The water quality design fl�v�shall be as follows,whichever is applicable:
a. Downstream of flow control facility:The full 2-year pre-developed al(owable
rate release rate from the ilow contro)facility. �
� Ms.Henninger
Page2of3
October 31,2012
2. The Storm Filter system shall be sized as described in the BayFilterTM'Technica!and
� . Design Monual,and the designer shall select the result yielding the larger number of
cartridges. .
3. Pre-settling shall be provided per Section 6.5.1 of the 2009 KCSWDM, General
Requirements fior Media Filtration Facilities.
4. BayFrlter'"systems shall be installed in such a manner that the flows exceeding the
design flow rates are bypassed around the Ba�lter Water Quality treatment facility. An '
external bypass to handle flow exceeding the facility design shall be provided. ,
5. The following maximum flow rates per cartridge system is limited to the following:
a. BayFilter Cartridge(BFC) Cartridge maximum flow rate of 0.7 gpm/sf.
i. 30 gpm (0.067 cfs) per cartridge (43 sf filter area).
ii. 26 inches in diameter and approximately 28.75 inches tall.
6. Media combinations forthe BayFilterTM'cartridges are limited to Silica Sand, Perlite,
- Zeolite, and Activated Alumina. All filters are limited to the 19"vertical component to
the spiral filter lay2rs.
7. Vaults used for tne BayFilterTM'System shall conforrn to the "Materials"and "Structural
Stability" requirements specified in Section 5.33 of the 2009 KCWDM for detention
vaults.
8. The BayFiltern'"system must be installed in an area that is accessible to maintenance
equipment. The maintenance of a BayFilterT"'system requires a vacuum truck as well as
the removal and replacement of the fiiter cartridges. i he manhole covers, and/or .
access hatches of the BayFilterTM'System must be placed in locations ihat can be easily
reached br s�.:ch a v�hicl�.
9. Access Requirements: �
a. Access consistent with City confined entry policy must be provided by either �
removab(e panels or other City approved accesses to allow for removal and
I"��^,��cem�nt ef the Ba;�Filter c?rtri�a?S.�!rrro��?d 2ccess details for the Storm
Filte!'System ma��be �,sed as eX2�?'?��e and zre ava�lablP in Reference Section 7C
of the 2009 KCSWDM_ �
b. Removable panels, if used, shali be at grade, have stainless steel lifting eyes, and
weigh no more than 5 tens per pane!. � �
c. Access io ihe in�low and �u��et cells�ust aiso be �ravi�ed.
.�. �ZG�`���Z.r.C2S5!S ��^yL':Tp�::��'1pC!VG�UIL�P{pf�t QXreP�S a IE?L.
e. Structures and access covers shafi be designed Tor HS20 traitic loading.
f. Removable panel access for vault s�al! not be located within the street
pavement section. .
1�J. i:�s�(IGtion of a �ayFilter'`"'syst�rn sha11 falio;ni ihe manu�ac�urer's r�comm��ded
h!"OC2�I,f�S.
H:\Fi;e Sy;\SVJ?-Suracz L'vatei Projects\SWP-27-Surface 4Jaier Frojec`s(CiFj\27-3123 Renio�Sterm�vaier
f�^�rt;al���C•JUST�9EN?S�ZOy_2;?nl?1}c�r�chmp4 Pf�t-ho��ilt2f.rlpr\[-!na�
Ms.Henninger . '
� Page 3 of 3
October3l,2012 •
. 11. The Bay Filter'"'system shall be inspected every six(6) months during the 2-year
maintenance defect bond period following completion of construction and plat �
recording..The owner is responsible for the maintenance of the Bay FilterTM'system �
during the 2-year defect bod period. The City will maintain the facility afterthe two
year maintenance and defect bond period expires.
� 12. When BayFilter exhibits flows below design levels,the system should be inspected and
maintained as soon as practical. Replacing a BayFilter cartridge should be considered at
or above the level of the 4"collector pipes to the manifold. Maintenance procedures
can be found in the BayFilter System Technical and Design Manual. The maintenance
process comprises the removal and replacement of each BayFilter cartridge and the
cleaning af the vault or manhole with a vacuum truck.
13. This is a conceptual approval for using the BayFilter for Basic Water Quality Treatment.
Further analysis and design calculations shall be included in the TIR for final approval.
. 14. The approval of this adjustment to use the Bay�ilter System for the Saddlebrook Plat
does not authorize the use of the BayFilter System on future projects without prior
approval from the City of Renton.
15.- The BayFifter system shall be installed in accordance with the approved drawings and
shall not be located within City right-of-way or easements.
Please note that the approval of this adjustment does not relieve the applicant from other city, �
state, or�ederal requirements. If you have any questions about this adjustment, please contact
Hebe C. Bernardo or me.
Attachments �
cc: Lys Hornsby,P.E.,Utiiiry Systems Director
Kayren Kittrick,Development Engineering Supervisor
Richzrd Marshz!,Surface W=ter and 1A�ater Maintenance Manager
Vanessa Dolbee,Planner
File
N:\File Sys\54"J?-Sufac2 Wat2r Projects\SWP-�7-Surface bVater Projeds(C1P)\27-3124 Rentan Stcrmwater
� Manual�ADJUSTMENTS\2012\2012-4 Sattlebrook Plat-hayfilter.doc\HEah
SECTION VIII
ESC PLAN ANALYSIS AND DESIGN (PART A)
The Erosion and Sedimentation Control Design will meet the nine minimum
requirements:
1. Clearing Limits - Areas to remain undisturbed shall be delineated with a high
visibility plastic fence prior to any site clearing or grading.
2. Cover Measures - Site disturbed areas shall be covered with mulch and
seeded, as appropriate, for temporary or permanent measures.
3. Perimeter Protection - Perimeter protection shall consist of a silt fence down
slope of any disturbed areas or stockpiles.
4. Traffic Area Stabilization - A stabilized construction entrance will be located at
the point of ingress/egress.
5. Sediment Retention — The proposed detention pond will be used as a sediment
pond.
6. Surface Water Control - Surface water control will be provided by interceptor
swales.
7. Dewatering Control — Not Applicable to this Site.
8. Dust Control - Dust control shall be provided by spraying exposed soils with
water until wet. This is required when exposed soils are dry to the point that
wind transport is possible which would impact roadways, drainage ways,
surface waters, or neighboring residences.
9. Flow Control — Flow control will be provided by the detention pond.
SWPPS PLAN DESIGN (PART B)
Construction activities that could contribute pollutants to surface and storm water
include the following, with applicable BMP's listed for each item:
1. Storage and use of chemicals: Utilize source control, and soil erosion and
sedimentation control practices, such as using only recommended amounts of
chemical materials applied in the proper manner; neutralizing concrete wash
water, and disposing of excess concrete material only in areas prepared for
concrete placement, or return to batch plant; disposing of wash-up waters from
water-based paints in sanitary sewer; disposing of wastes from oil-based paints,
solvents, thinners, and mineral spirits only through a licensed waste
management firm, or treatment, storage, and disposal (TSD) facility.
2. Material delivery and storage: Locate temporary storage areas away from
vehicular traffic, near the construction entrance, and away from storm drains.
Material Safety Data Sheets (MSDS) should be supplied for all materials stored,
and chemicals kept in their original labeled containers. Maintenance, fueling,
and repair of heavy equipment and vehicles shall be conducted using spill
O 2013 D.R.STRONG Consulting Engineers Inc. 41 Saddlebrook Div. II
Technical Information Report Renton,Washington
prevention and control measures. Contaminated surfaces shall be cleaned
immediately following any spill incident. Provide cover, containment, and
protection from vandalism for all chemicals, liquid products, petroleum products,
and other potentially hazardous materials.
3. Building demolition: Protect stormwater drainage system from sediment-laden
runoff and loose particles. To the extent possible, use dikes, berms, or other
methods to protect overland discharge paths from runoff. Street gutter,
sidewalks, driveways, and other paved surFaces in the immediate area of
demolition must be swept daily to collect and properly dispose of loose debris
and garbage. Spray the minimum amount of water to help control windblown
fine particles such as concrete, dust, and paint chips. Avoid excessive spraying
so that runoff from the site does not occur, yet dust control is achieved. Oils
must never be used for dust control.
4. Sawcutting: Slurry and cuttings shall be vacuumed during the activity to prevent
migration offsite and must not remain on permanent concrete or asphalt paving
overnight. Collected slurry and cuttings shall be disposed of in a manner that
does not violate ground water or surface water quality standards.
The complete CSWPPP can be found in Appendix D of this report.
O 2013 D.R.STRONG Consulting Engineers Inc. 42 Saddlebrook Div. II I�
Technical Information Report Renton,Washington ,
SECTION IX
BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
1. Bond Quantity Worksheet— attached in Appendix B
2. Facility Summary— attached.
3. Declaration of Covenant—will be provided prior to final engineering approval.
O 2013 D.R.STRONG Consulting Engineers Inc. 43 Saddlebrook Div. II
Technical Information Report Renton,Washington
STORMWATER FACILITY SUMMARY SHEET
Development Saddlebrook Div. I and Div. II Date Auqust 7, 2013
I Location 13422 156th Avenue SE, Renton, Washinqton
ENGINEER DEVELOPER
Name Maher A. Joudi, P.E. Name '
' ; Firm D. R. STRONG Consulting Firm: ACH Homes, LLC
En ineers, Inc.
Address 620 7 Avenue Address 9675 SE 36 Street, # 105
Kirkland, WA 98033 Mercer Island, WA 98040
Phone 425 827-3063 Phone 206 588-1147
Developed Site: 5.54 acres
Number of lots Seventeen (Total for Div. I and Div. II)
Number of detention facilities on site: Number of infiltration facilities on site:
1 pond ponds
vaults vaults
tanks tanks
Flow control provided in regional facility (give
location)
No flow control required Exemption number
Downstream Draina e Basins
Immediate Major Basin
Basin Lower Cedar River Cedar River
Number & type of water quality facilities on site:
biofiltration swale (regular/wet/ or continuous inflow?)
sand filter (basic or large?) sand filter, linear (basic or
large?) 1 BayFilter
1 detention pond sand filter vault (basic or large?)
combined detention/wetvault stormwater wetland
compost filter wetpond (basic or large?)
filter strip wetvault
34 flow dispersion pre-settling pond
farm management plan flow-splitter catchbasin
O 2013 D.R. STRONG Consulting Engineers Inc. 44 Saddlebrook Div. II
Technical Information Report Renton,Washington
landscape management plan
oil/water separator (baffle or coalescing plate?)
catch basin inserts:
Manufacturer
pre-settling structure:
Manufacturer
DESIGN INFORMATION INDIVIDUAL BASIN
_ East
Water Quality design flow
Water Quality treated volume
Drainage basin(s) 2
Onsite area (inlcudes frontage) 5.54 ac.
, Offsite area 0
' Type of Storage Facility Pond
Live Storage Volume (required) 62,868
Predev Runoff Rate 2-year 0.154
10-year 0.268
100-year 0.447
Developed Runoff Rate 2-year 0.083
(Including Bypass Rate) 10-year 0.228
100-year 0.444
Type of Restrictor Fro -Tee
Size of orifice/restriction No. 1 1.11
No. 2 2.14
No. 3 2.54
No. 4 N/A
�:�2013 D. R.STRONG Consulting Engineers Inc. 45 Saddlebrook Div. II
Technical Information Report Renton,Washington
—
SECTION X 'I
OPERATIONS AND MAINTENANCE MANUAL '�
See Appendix C for excerpts from the 2009 King County Surface Water Design Manual �
with regard to Operations and Maintenance. ,
O 2013 D. R. STRONG Consulting Engineers Inc. 46 Saddlebrook Div. II I
Technical Information Report Renton,Washington
�i
APPENDICES
O 2013 D.R.STRONG Consulting Engineers Inc. 47 Saddlebrook Div. II
Technical Information Report Renton,Washington
APPENDIX "A" LEGAL DESCRIPTION
THE SOUTH 130 FEET OF LOT 5 IN BLOCK 2 OF JANETT'S RENTON BOULEVARD
TRACTS, ACCORDING TO PLAT RECORDED IN VOLUME 17 OF PLATS AT ,
PAGE(S) 60, IN KING COUNTY, WASHINGTON; EXCEPT THE EAST 290 FEET I
THEREOF. '
�2013 D. R.STRONG Consulting Engineers Inc. 48 Saddlebrook Div. II
Technical Information Report Renton,Washington
APPENDIX "B" BOND QUANTITY WORKSHEET
� O 2013 D.R.STRONG Consulting Engineers Inc. 49 Saddlebrook Div. II
Technical Information Report Renton,Washington
�
Web date: 12/02/2008
Site Improvement Bond Quantity Worksheet
� King County
Department of Development & Environmental Services
900 Oakesdale Avenue Southwest
Renton, Washington 98057-5212 For alternate formats, ca11206-296-6600.
206-296-6600 TTY 206-296-7217
Project Name: Saddlebrook I I Date: 7-Aug-13
Location: Rentoll Project No.:
Activity No.:
Note: All prices include labor, equipment, materials, overhead and
Clearing greater than or equal to 5,000 board feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area
or from local sources if not included in the RS Means database.
yes X no
If yes,
Forest Practice Permit Number:
(RCW 76.09)
Page 1 of 9
Unit prices updated: 02/12/02
Version: 11/26/2008
Bond Quantity Worksheet13030.x1sx Report Date: 8/7/2013
s : _ . 1
Site Improvement Bond Quantity Worksheet Webdate: '2,°2,2°°8
n't #of
Ui
Reference# Price Unit Quantity Applications Cost
EROSION/SEDIMENT CONTROL Number
Backfill &compaction-embankment ESC-1 $ 5.62 CY
Check dams,4" minus rock ESC-2 SWDM 5.4.6.3 $ 67.51 Each 3 1 203
Crushed surfacing 1 1/4" minus ESC-3 WSDOT 9-03.9(3) $ 85.45 CY
Ditchin ESC-4 $ 8.08 CY 35.55555556 1 287
Excavation-bulk ESC-5 $ 1.50 CY
Fence, silt ESC-6 SWDM 5.4.3.1 $ 1.38 LF 387 1 534
Fence,Tempora (NGPE) ESC-7 $ 1.38 LF 1004 1 1386
Hydroseeding ESC-8 SWDM 5.4.2.4 $ 0.59 SY 797.6666667 1 471
Jute Mesh ESC-9 SWDM 5.4.2.2 $ 1.45 SY
Mulch, by hand, straw, 3"deep ESC-10 SWDM 5.4.2.1 $ 2.01 SY 797.6666667
Mulch, by machine, straw, 2"deep ESC-11 SWDM 5.4.2.1 $ 0.53 SY
Pipin ,tempora , CPP,6" ESC-12 $ 10.70 LF
Pi ing,temporary, CPP, 8" ESC-13 $ 16.10 LF
Piping,temporary, CPP, 12" ESC-14 $ 20.70 LF 34 1 704
Plastic coverin ,6mm thick, sandbagged ESC-15 SWDM 5.4.2.3 $ 2.30 SY 51.85185185 1 119
Rip Rap, machine placed; slopes ESC-16 WSDOT 9-13.1(2) $ 39.08 CY
Rock Construction Entrance, 50'x15'x1' ESC-17 SWDM 5.4.4.1 $ 1,464.34 Each
Rock Construction Entrance, 100'x15'x1' ESC-18 SWDM 5.4.4.1 $ 2,928.68 Each 1 1 2929
Sediment pond riser assembly ESC-19 SWDM 5.4.5.2 $ 1,949.38 Each
Sediment trap, 5' high berm ESC-20 SWDM 5.4.5.1 $ 17.91 LF
Sed.trap, 5'high, riprapped spillway berm section ESC-21 SWDM 5.4.5.1 $ 68.54 LF 131 1 8979
Seeding, by hand ESC-22 SWDM 5.4.2.4 $ 0.51 SY
Sodding, 1"deep, level ground ESC-23 SWDM 5.4.2.5 $ 6.03 SY
Sodding, 1"deep, sloped ground ESC-24 SWDM 5.4.2.5 $ 7.45 SY
TESC Supervisor ESC-25 $ 74.75 HR 20 1 1495
Water truck, dust control ESC-26 SWDM 5.4.7 $ 97.75 HR 2 1 196
WRITE-IN-ITEMS **** (see paqe 9) !
Each
ESC SUBTOTAL: $ 17,301.00
30%CONTINGENCY&MOBILIZATION: $ 5,190.30
ESC TOTAL: $ 22,491.30
COLUMN: A
Page 2 of 9
Unit prices updated: 02/12/02
Version: 11/26/2008
Bond Quantity Worksheet13030.x1sx Report Date: 8/7/2013
Site Improvement Bond Quantity Worksheet Webdate 12/02/2008
Existing Future Public Private Quantity Completed
Right-of-Way Right of Way Improvements (Bond Reduction)"
&Draina e Facilities Quant.
Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost
GENERALITEMS No.
Backfill&Compaction-embankment GI-1 $ 5.62 CY 208 1,168.96
Backfill&Compaclion-trench GI-2 $ 8.53 CY 5 42.65 30 255.90
Clear/Remove Brush,b hand GI-3 $ 0.36 SY
Clearin /Grubbin /Tree Removal GI-4 $ 8,876.16 Acre 0.04 355.05 0.494 4,384.82
Excavation-bulk GI-5 $ 1.50 CY 211 316.50
Excavation-Trench GI-6 $ 4.06 CY 5 20.30 30 121.80
Fencin ,cedar,6'hi h GI-7 $ 18.55 LF
Fencin ,chain link,vin I coated, 6'hi h GI-8 $ 13.44 LF
Fencin ,chain link, ate,vin I coated, 2 GI-9 $ 1,271.81 Each
Fencin ,split rail,3'hi h GI-10 $ 12.12 LF
Fill&com act-common barrow GI-11 $ 22.57 CY
Fill&com act- ravel base GI-12 $ 25.48 CY
Fill&com act-screened to soil GI-13 $ 37.85 CY I
Gabion, 12"deep,stone filled mesh GI-14 $ 54.31 SY �
Gabion, 18"deep,stone filled mesh GI-15 $ 74.85 SY
Gabion,36"deep,stone filled mesh GI-16 $ 132.48 SY
Grading,fine,b hand GI-17 $ 2.02 SY
Grading,fine,with grader GI-18 $ 0.95 SY
Monuments,3'lon GI-19 $ 135.13 Each
Sensitive Areas Si n GI-20 $ 2.88 Each
Sodding, 1"deep,slo ed ground GI-21 $ 7.46 SY
Surve in ,line& rade GI-22 $ 788.26 Da 1 788.26
Surve ing,lot location/lines GI-23 $ 1,556.64 Acre 1 1,556.64
Traffic control crew(2 fla ers) GI-24 $ 85.18 HR 6 511.08
Trail,4"chipped wood GI-25 $ 7.59 SY
Trail,4"crushed cinder GI-26 $ 8.33 SY
Trail,4"top course GI-27 $ 8.19 SY
Wall,retainin ,concrete GI-28 $ 44.16 SF
Wall,rockery GI-29 $ 9.49 SF
Page 3 of 9 SUBTOTAL 929.08 8,592.88
Unit prices updated: 02/12/02
'KCC 27A authorizes only one bond reduction. Ve�SIOn: 11/26/08
Dond Quantity V`Jorksheet13030.x1sx Report Date: 8/7/2013
Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008
Existing Future Public Private Bond Reduction*
Right-of-way Right of Way Improvements
8 Drainage Facilities Quant.
Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost
ROADIMPROVEMENT No.
AC Grindin ,4'wide machine<1000s RI-1 $ 28.00 SY
AC Grindin ,4'wide machine 1000-200 RI-2 $ 15.00 SY
AC Grinding,4'wide machine>2000s RI-3 $ 7.00 SY
AC Removal/Dis osal/Re air RI-4 $ 67.50 SY 261.778 17,670.00
Barricade,t e I RI-5 $ 30.03 LF
Barricade,t e III Permanent) RI-6 $ 45.05 LF
Curb&Gutter,rolled RI-7 $ 17.00 LF
Curb&Gutter,vertical RI-8 $ 12.50 LF 132 1,650.00
Curb and Gutter,demolition and dis osa RI-9 $ 18.00 LF
Curb,extruded asphalt RI-10 $ 5.50 LF �
Curb,extruded concrete RI-11 $ 7.00 LF
Sawcut,as halt,3"de th RI-12 $ 1.85 LF 430 795.50 �
Sawcut,concrete,per 1"depth RI-13 $ 1.69 LF I,
Sealant,as halt RI-14 $ 1.25 LF 430 537.50
Shoulder,AC, see AC road unit price) RI-15 $ - SY
Shoulder,gravel,4"thick RI-16 $ 15.00 SY
Sidewalk,4"thick RI-17 $ 35.00 SY 835 29,225.00
Sidewalk,4"thick,demolition and dis os RI-18 $ 29.50 SY
Sidewalk,5"thick RI-19 $ 38.50 SY
Sidewalk,5"thick,demolition and dis os RI-20 $ 37.50 SY
Si n,handica RI-21 $ 85.28 Each
Striping,per stall RI-22 $ 5.82 Each
Striping,thermoplastic,(for crosswalk) RI-23 $ 2.38 SF
Striping,4"reflectorized line RI-24 $ 0.25 LF
Page 4 of 9 SUBTOTAL 49,878.00
Unit prices updated: 02/12/02
'KCC 27A authorizes only one bond reduction. VerSion: 11/26/08
Bond Quantity Worksheet13030.x1sx Report Date: 8/7/2013
Site Improvement Bond Quantity Worksheet Webdate 12/02/2008
Existing Future Public Private Bond Reduction'
Right-of-way Right of Way Improvements
&Drainage Facilities Quant.
Unit Price Unit Quant. Cost Quant Cost QuanL Cost Complete Cost
ROAD SURFACING (4"Rock=2.5 base&1.5"top course) For'93 KCRS(G.5"Rock=5"base&1.5"top course)
For KCRS'93,(additional 2.5"base)add RS-1 $ 3.60 SY
AC Overla , 1.5"AC RS-2 $ 11.25 SY
AC Overla ,2"AC RS-3 $ 15.00 SY
AC Road,2",4"rock,First 2500 SY RS-4 $ 21.00 SY 281.556 5,912.67
AC Road,2",4"rock,Qt .over 2500SY RS-5 $ 19.00 SY
AC Road,3",4"rock,First 2500 SY RS-6 $ 23.30 SY
AC Road,3",4"rock,Qt .over 2500 SY RS-7 $ 21.00 SY
AC Road,5",First 2500 SY RS-8 $ 27.60 SY 498.111 13,747.87
AC Road,5",Qt .Over 2500 SY RS-9 $ 25.00 SY
AC Road,6",First 2500 SY RS-1 $ 33.10 SY
AC Road,6",Qt .Over 2500 SY RS-11 $ 30.00 SY
Asphalt Treated Base,4"thick RS-1 $ 20.00 SY
Gravel Road,4"rock,First 2500 SY RS-1 $ 15.00 SY
Gravel Road,4"rock,Qt .over 2500 SY RS-14 $ 8.50 SY
PCC Road,5",no base,over 2500 SY RS-1 $ 27.00 SY
PCC Road, 6",no base,over 2500 SY RS-1 $ 25.50 SY
Thickened Edge RS-1 i $ 8.60 LF
Page 5 of 9 SUBTOTAL 5,912.67 13,747.87 I
Unit prices updated: 02/12/02
'KCC 27A authorizes only one bond reduction. VerSiOn: 11/26/08
Bond Quantity VVorksheet13030.x1sx Report Date: 8/7/2013
Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008
Existing Future Public Private Bond Reduction"
Right-of-way Right of Way Improvements
8 Drainage Facilities Quant.
Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost
DRAI NAGE (CPP=Cor�ugated PIBStiC Pipe,N12 or Equivalent) For Culvert rices, Average of 4'cover was assumed.Assume perforated PVC is same price as solid pipe.
Access Road, R/D D-1 $ 21.00 SY
Bollards-fixed D-2 $ 240.74 Each
Bollards-removable D-3 $ 452.34 Each
" CBs include frame and lid)
CBT el D-4 $ 1,257.64 Each 1 1,257.64 1 1,257.64
CB T e IL D-5 $ 1,433.59 Each
CB T e II,48"diameter D-6 $ 2,033.57 Each
for additional de th over 4' D-7 $ 436.52 FT
CB T pe II,54"diameter D-8 $ 2,192.54 Each
for additional depth over 4' D-9 $ 486.53 FT
CB T pe II,60"diameter D-10 $ 2,351.52 Each
for additionat de th over 4' D-11 $ 536.54 FT
CB T pe II,72"diameter D-12 $ 3,212.64 Each
for additional depth over 4' D-13 $ 692.21 FT
Throu h-curb Inlet Framework(Add) D-14 $ 366.09 Each
Cleanout,PVC,4" D-15 $ 130.55 Each
Cleanout, PVC,6" D-16 $ 174.90 Each
Cleanout, PVC,8" D-17 $ 224.19 Each
Cuivert,PVC,4" D-18 $ 8.64 LF
Culvert,PVC,6" D-19 $ 12.60 LF
Culvert,PVC, 8" D-20 $ 13.33 LF
Culvert,PVC, 12" D-21 $ 21.77 LF
Culvert,CMP,8" D-22 $ 17.25 LF
Culvert,CMP, 12" D-23 $ 26.45 LF
Culvert,CMP, 15" D-24 $ 32.73 LF
Culvert,CMP, 18" D-25 $ 37.74 LF
Culvert,CMP,24" D-26 $ 53.33 LF
Culvert,CMP,30" D-27 $ 71.45 LF
Culvert,CMP,36" D-28 $ 112.11 LF
Culvert,CMP,48" D-29 $ 140.83 LF
Culvert,CMP,60" D-30 $ 235.45 LF
Culvert,CMP,72" D-31 $ 302.58 LF
Page 6 of 9 SUBTOTAL 1,257.64 1,257.64
Unit prices updated: 02/12/02
*KCC 27A authorizes only one bond reduction. VerSion: 11/26/08
Bond Quantity Worksheet13030.x1sx Report Date: 8/7/2013
Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008
Existing Future Public Private Bond Reduction" I�
Right-of-way Right of Way Improvcments
DRAINAGE CONTINUED &Drainage Facilities Quant. ,
No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Completc Cost
Culvert,Concrete,8" D-32 $ 21.02 LF
Culvert,Concrete, 12" D-33 $ 30.05 LF
Culvert,Concrete, 15" D-34 $ 37.34 LF
Culvert,Concrete, 18" D-35 $ 44.51 LF
Culvert,Concrete,24" D-36 $ 61.07 LF
Culvert,Concrete,30" D-37 $ 104.18 LF
Culvert,Concrete,36" D-38 $ 137.63 LF
Culvert,Concrete,42" D-39 $ 158.42 LF
Culvert,Concrete,48" D-40 $ 175.94 LF
Culvert,CPP,6" D-41 $ 10.70 LF 195 2086.5
Culvert,CPP,8" D-42 $ 16.10 LF
Culvert,CPP, 12" D-43 $ 20.70 LF 14 289.8 63 1304.1
Culvert,CPP, 15" D-44 $ 23.00 LF
Culvert,CPP, 18" D-45 $ 27.60 LF
Culvert,CPP,24" D-46 $ 36.80 LF
Culvert,CPP,30" D-47 $ 48.30 LF
Culvert,CPP,36" D-48 $ 55.20 LF
Ditchin D-49 $ 8.08 CY
Flow Dispersal Trench (1,436 base+) D-50 $ 25.99 LF
French Drain 3'de th D-51 $ 22.60 LF
Geote�ile,laid in trench, ol pro lene D-52 $ 2.40 SY
Infiltration pond testing D-53 $ 74.75 HR
Mid-tank Access Riser,48"dia, 6'dee D-54 $ 1,605.40 Each
Pond Overflow Spillwa D-55 $ 14.01 SY
Restrictor/Oil Separator, 12" D-56 $ 1,045.19 Each
Restrictor/Oil Separator, 15" D-57 $ 1,095.56 Each
Restrictor/Oil Separator, 18" D-58 $ 1,146.16 Each
Riprap,placed D-59 $ 39.08 CY
Tank End Reducer(36"diameter) D-60 $ 1,000.50 Each
Trash Rack, 12" D-61 $ 211.97 Each
Trash Rack, 15" D-62 $ 237.27 Each
Trash Rack, 18" D-63 $ 268.89 Each
Trash Rack,21" D-64 $ 306.84 Each
Page 7 of 9 SUBTOTAL 289.8 3390.6
Unit prices updated: 02/12/02
*KCC 27A authorizes only one bond reduction. Ve�SiOn: 11/26/08
Bond Quantity Worksheet13030.x1sx Report Date: 8/7/2013
Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008
Existing Future Public Private Bond Reduction' '�
Right-of-way Right of Way Improvements
&Drainage Facilities Quant. !
Unit Price Unit Quant. Price Quant. Cost Quant. Cost Complete Cost
PARKING LOT SURFACING
N o.
2"AC,2"top course rock&4"borrow PL-1 $ 21.00 SY
2"AC, 1.5" to course 8�2.5"base cour PL-2 $ 28.00 SY
4"select borrow PL-3 $ 4.55 SY
1.5"top course rock&2.5"base course PL-4 $ 11.41 SY
UTILITY POLES 8� STREET LIGHTING Utili ole relocation costs must be accompanied by Franchise Utility's Cost Statement
Utilit Pole s Relocation UP-1 $ 10,000.00
Street Li ht Poles w/Luminaires UP-2 $ 3,000.00 Each
WRITE-IN-ITEMS
(Such as detention/water ualit vaults. No.
WI-1 Each
WI-2 Each
WI-3 Each
WI-4 LF
WI-5 FT
WI-6
WI-7
WI-8
WI-9
wi-�o
SUBTOTAL
SUBTOTAL(SUM ALL PAGES): 58,267.18 26,988.99
30%CONTINGENCY&MOBILIZATION: 17,480.15 8,096.70
GRANDTOTAL: 75,747.34 35,085.69
COLUMN: B C D E
Page 8 of 9 _
Unit prices updated: 02/12/02
'KCC 27A authorizes only one bond reduction. VefSlon: 11/26/08
Bond Quantity Worksheet13030.x1sx Report Date: 8/7/2013 �
-- ---- _ _ �
Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008
Original bond computations prepared by:
Name: Maher A. Joudi Date: 7-Aug-13
PE Registration Number: 45232 Tel.#: (425) 827-3063
Firm Name: DR STRONG Consulting Engineers, Inc.
adaress: 620 7th Avenue Kirkland, WA 98033 Project No:
ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS
PERFORMANCE BOND" PUBLIC ROAD&DRAINAGE
AMOUNT BOND'AMOUNT MAINTENANCE/DEFECT BOND'
REQUIRED AT RECORDING OR
Stabilization/Erosion Sediment Control (ESC) (A) $ 22,491.3 TEMPORARY OCCUPANCY"'
Existing Right-of-Way Improvements (B) $ 75,747.3
Future Public Right of Way&Drainage Facilities (C) $ -
Private Improvements (D) $ 35,085.7
Calculated Quantity Completed (E). $ -
Total Right-of Way and/or Site Restoration Bond*/'`"` (A+B) $ 98,238.6
(First$7,500 of bond*shall be cash.)
Performance Bond*Amount (A+g+C+D) = TOTAL (� $ 133,324.3 T x 0.30 $ 39,997.3 OR
Minimum bond'amount is 2 .
Reduced Performance Bond*Total'"** (T-E) $ 133,324.3
Use larger o Tx30/o or(T-E (g+C)x
Maintenance/Defect Bond*Total 0.25= $ 18,936.8
NAME OF PERSON PREPARING BOND*REDUCTION: Date:
"NOTE: The word"bond"as used in this document means a financial guarantee acceptable to King County.
'*NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required.
The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition, corrective work,both on-and off-site needs to be included.
Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged,some estimated costs for restoration
needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity.
***NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised by major design changes.
REQUIRED BOND"AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES
Page 9 of 9 Unit prices updated: 02/12/02
Check out the DDES Web site at www.kinqcountv.qov/permits Version: 11/26/08
Bond Quantity Worksheet13030.x1sx Report Date: 8/7/2013
APPENDIX "C" OPERATIONS AND MAINTENACE MANUAL
I
I'
�I �_`,
„
O 2013 D. R.STRONG Consulting Engineers Inc. 50 Saddlebrook Div. II
Technical Information Report Renton,Washington
APPENDIX A MAIN"TENANCE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND��VQ FACILITIES
N0. 1 -DETENTION PONDS
Maintenance Defect or Probiem Conditions When Maintenance Is Needed Results Expected When
Component Maintenance Is Performed
Site Trash and debris Any frash and debris which exceed 1 cubic foot Trash and debris cleared from site.
per 1,000 square feet(this is about equal to the
amount of trash it would take to fill up one
standard size office garbage can). In general,
there should be no visual evidence of dumping.
Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation
constitute a hazard to County personnel or the removed according to applicable
public. regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a
height. height no greater than 6 inches.
Top or Side Slopes Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and
of Dam,Berm or as a dam or berm,or any evidence of water dam or berm repaired.
Embankment piping through dam or berm via rodent holes.
Tree growth Tree growth threatens integrity of slopes,does Trees do not hinder facility
not allow maintenance access,or interferes with performance or maintenance
maintenance activity. If trees are not a threat or activities.
not interfering with access or maintenance,they
do nat need to be removed.
Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate
of damage is still present or where there is erosion control measures. If erosion
potential for continued erosion. Any erosion is occurring on compacted slope,a
observed on a compacted slope. licensed civil engineer should be
consulted to resolve source of
erosion.
Settlement Any part of a dam,berm or embankment that has Top or side slope restored to design
settled 4 inches lower than the design elevation. dimensions. If settlement is
significant,a licensed civil engineer
should be consulted to determine
the cause of the settlement.
Storage Area Sediment Accumulated sediment that exceeds 10%of the Sediment cleaned out to designed
accumulation designed pond depth. pond shape and depth;pond
reseeded if necessary to control
erosion.
Liner damaged Liner is visible or pond does not hold water as Liner repaired or replaced.
(If Applicable) designed.
InletlOutlet Pipe. Sediment Sediment filling 20%or more of the pipe. Inleboutlet pipes clear of sediment.
accumulation
Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes.
pipes(includes floatables and non-floatables).
Damaged Cracks wider than%rinch at the joint of the No cracks more than'/-inch wide at
inleVoutlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe.
at the joints of the inlet/outlet pipes.
Emergency Tree growth Tree growth impedes flow or threatens stability of Trees removed.
Overflow/Spil Iway spilhvay.
Rock missing Only one layer of rock exists above native soil in Spiliway restored to design
area five square feet or larger or any exposure of standards.
native soil on the spillway.
1i9i2009 2009 Surface Water Design Manual—�ppendix A
A-2
APPENDIX A MAINTENANCE REQUIRE�NTS FOR FLOW CONTROL,CONVEYANCE,AND�'VQ FACILITIES
NO.4-CONTROL STRUCTUREIFLOW RESTRICTOR
Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When
Component Maintenance is Performed
Structure Trash and debris Trash or debris of more than%cubic foot which No Trash or debris blocking or
is located immediately in front of the structure potentially blocking entrance to
opening or is blocking capacity of the structure by structure.
more than 10%.
Trash or debris in the structure that exceeds'/3 No trash or debris in the structure.
the depth from the bottom of basin to invert the
lowest pipe into or out of the basin.
Deposits of garbage exceeding 1 cubic foot in No condition present which would
volume. attract or support the breeding of
insects or rodents.
Sediment Sediment exceeds 60%of the depth from the Sump of structure contains no
bottom of the structure to the invert of the lowest sediment.
pipe into or out of the structure or the bottom of
the FROP-T section or is within 6 inches of the
invert of the lowest pipe into or out of the
structure or the bottom of the FROP-T section.
Damage to frame Corner of frame extends more than'/+inch past Frame is even with curb.
and/or top slab curb face into the street(If applicable).
Top slab has holes larger than 2 square inches or Top siab is free of holes and cracks.
cracks wider than%inch.
Frame not sitting flush on top slab,i.e., Frame is sitting flush on top slab.
separation of more than'/+inch of the frame from
the top slab.
Cracks in walis or Cracks wider than%:inch and longer than 3 feet, Structure is sealed and structurally
bottom any evidence of soil particles entering structure sound.
through cracks,or maintenance person judges
that structure is unsound.
Cracks wider than'h inch and longer than 1 foot No cracks more than'/,inch wide at
at the joint of any inlet/outlet pipe or any evidence the joint of inlet/outlet pipe.
of soil particles entering structure through cracks.
SettlemenU Structure has settled more than 1 inch or has Basin replaced or repaired to design
misalignment rotated more than 2 inches out of alignment. standards.
Damaged pipe joints Cracks wider than Yrinch at the joint of the No cracks more than'/<-inch wide at
inletJoutlet pipes or any evidence of soil entering the joint of inleUoutlet pipes.
the structure at the joint of the inlet/outlet pipes.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oii film.
Ladder rungs missing Ladder is unsafe due to missing rungs, Ladder meets design standards and
or unsafe misalignment, rust,cracks,or sharp edges. allows maintenance person safe
access.
FROP-T Section Damage T section is not securely attached to structure T section securely attached to wall
wall and outlet pipe structure should support at and outlet pipe.
least 1,000 Ibs of up or down pressure.
Structure is not in upright position(allow up to Structure in correct position.
10%from plumb).
Connections to outlet pipe are not watertight or Connections to outlet pipe are water
show signs of deteriorated grout. tight;structure repaired or replaced
and works as designed.
Any holes—other than designed holes—in the Structure has no holes other than
structure. designed holes.
Cleanout Gate Damaged or missing Cleanout gate is missing. Replace cleanout gate.
2009 Surface Water Design Manual–Appendix A 1/9/2009
A-7
APPE\DIX A n7ALNTENANCE REQtiIREA1LNTS PLOW CONTROL,CONVEY�NCE,IIND\�'Q FACILITIES
NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR
Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When
Component Maintenance is Performed
Cleanout gate is not watertight. Gate is watertight and works as
designed.
Gate cannot be moved up and down by one Gate moves up and down easily and
maintenance person. is watertight.
Chain/rod leading to gate is missing or damaged. Chain is in place and works as
designed.
Orifice Plate Damaged or missing Control device is not working properly due to Plate is in piace and works as
missing,out of place,or bent orifice plate. designed.
Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and
blocking the plate. �vorks as designed.
Overflow Pipe Obstructions Any trash or debris blocking(or having the Pipe is free of all obstructions and
potential of blocking)the overtlow pipe. works as designed.
Deformed or damaged Lip of overflow pipe is bent or deformed. O�erflow pipe does not allow
lip overflow at an elevation lower than
design
Inlet/Outlet Pipe Sediment Sediment filling 20%or more of the pipe. InleUoutlet pipes clear of sediment.
accumulation
Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes.
pipes(includes floatables and non-floatables).
Damaged Cracks wider than%rinch at the joint of the No cracks more than%-inch wide at
inleVoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe.
at the joints of the inletloutlet pipes.
Metal Grates Unsafe grate opening Grate with opening wider than'/e inch. Grate opening meets design
(If Applicable) standards.
Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris.
of grate surface. footnote to guidelines for disposal
Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design
standards.
Manhole CovedLid Cover/lid not in place Covedlid is missing or only partially in place. Cover/lid protects opening to
Any open structure requires urgent structure.
maintenance.
Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools.
Not Working maintenance person with proper tools.Boits
cannot be seated. Self-locking cover/lid does not
work.
Cover/lid difficult to One maintenance person cannot remove Cover/lid can be remo�ed and
Remove covedlid after applying 80 Ibs.of lift. reinstalled by one maintenance
person.
1/9/2009 2009 Surface Water Design Manual—Appendix A Ii
A-8 I
APPENDIX A MAI�ITENANCE REQUIREMENTS FOR FLOVV CONTROL,CONVEYANCE,AND WQ FACILITIES
NO. 5-CATCH BASINS AND MANHOLES
Maintenance Defect or Problem Condition When iVlaintenance is Needed Results Expected When
Component Maintenance is Performed
Structure Sediment Sediment exceeds 60%of the depth from the Sump of catch basin contains no
bottom of the catch basin to the invert of the sediment.
lowest pipe into or out of the catch basin or is
within 6 inches of the invert of the lowest pipe
into or out of the catch basin.
Trash and debris Trash or debris of more than%:cubic foot which No Trash or debris blocking or
is located immediately in front of the catch basin potentially blocking entrance to
opening or is blocking capacity of the catch basin catch basin.
by more than 10%.
Trash or debris in the catch basin that exceeds No trash or debris in the catch basin.
'/3 the depth from the bottom of basin to invert the
lowest pipe into or out of the basin.
Dead animals or vegetation that could generate No dead animals or vegetation
odors that could cause complaints or dangerous present within catch basin.
gases(e.g., methane).
Deposits of garbage exceeding 1 cubic foot in No condition present which would
volume. attract or support the breeding of
insects or rodents.
Damage to frame Comer of frame extends more than'/.inch past Frame is even with curb.
and/or top slab curb face into the street(If applicable).
Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks.
cracks wider than%.inch.
Frame not sitting flush on top slab,i.e., Frame is sitting flush on top slab.
separation of more than'/.inch of the frame from
the top slab.
Cracks in walls or Cracks wider than%:inch and longer than 3 feet, Catch basin is sealed and
bottom any evidence of soil particles entering catch structurally sound.
basin through cracks,or maintenance person
judges that catch basin is unsound.
Cracks wider than%inch and longer than 1 foot No cracks more than'/a inch wide at
at the joint of any inlet/outlet pipe or any evidence the joint of inleUoutiet pipe.
of soil paiticles entering catch basin through
cracks.
SettlemenU Catch basin has settied more than 1 inch or has Basin replaced or repaired to design
misalignment rotated more than 2 inches out of alignment. standards.
Damaged pipe joints Cracks wider than%rinch at the joint of the No cracks more than%-inch wide at
inlet/outlet pipes or any evidence of soil entering the joint of inleVoutlet pipes.
the catch basin at the joint of the inleUoutlet
pipes.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to applicabie regulations.
Source control BMPs irnplemented if
appropriate. No contaminants
present other than a surface oil film.
Inlet/Outlet Pipe Sediment Sediment filling 20%or more of the pipe. Inlet/outlet pipes clear of sediment.
accumulation
Trash and debris Trash and debris accumulated in inletloutlet No trash or debris in pipes.
pipes(includes floatables and non-floatables}.
Damaged Cracks wider than'/rinch at the joint of the No cracks more than%-inch wide at
inleUoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe.
at the joints of the inlet/outlet pipes.
2009 Surface���ater Design Manual—AppendLx A li9/2009
A-9
APPENDIX A MATNTENANCE REQUIltEMENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES '
NO. 5-CATCH BASINS AND MANHOLES
Maintenance Defect or Problem Condition When Maintenance is Needed Resulks Expected When
Component Maintenance is PerFormed
Metal Grates Unsafe grate opening Grate with opening wider than'/e inch. Grate opening meets design
(Catch Basins) standards.
Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris. I
of grate surface. footnofe to guidelines for disposal ,
Damaged or missing Grafe missing or broken member(s)of the grate. Grate is in place and meets design
Any open structure requires urgent standards.
maintenance.
Manhole CovedLid Cover/lid not in place Cover/lid is missing or only partially in place. Co�er/lid protects opening to
Any open structure requires urgent structure.
maintenance. �
Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools_
Not Working maintenance person with proper tools.Bolts
cannot be seated. Self-locking cover/lid does not
work.
Covedlid difficult to One maintenance person cannot remove Cover/lid can be removed and
Remove cover/lid after applying 80 Ibs.of lift. reinstalled by one maintenance
person.
1/9,'2009 2009 Surface�'�'ater Design I�lanual—�ppendix A
A-10
IAPPE'<VDIX A \�'�INTENANCE REQliIREI��fENTS FOR FLOW CONTROL,CONVEY�\TCE,r1I��VVQ F�CILITIES
NO. 6-CONVEYANCE PIPES AND DITCHES
' Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When
Component Maintenance is Performed
Pipes Sediment&debris Accumulated sediment or debris that exceeds Water flows freely through pipes.
accumulation 20%of the diameter of the pipe.
Vegetation/roots Vegetation/roots that reduce free movement of Water flows freely through pipes.
water through pipes.
Contaminants and Any evidence of contaminants or poilution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
' present other than a surface oil film.
Damage to protective Protective coating is damaged;rust or corrosion Pipe repaired or replaced.
coating or corrosion is weakening the structural integrity of any part of
pipe.
Damaged Any dent that decreases the cross section area of Pipe repaired or replaced.
pipe by more than 20%or is determined to have
weakened structural integrity of the pipe.
Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from
square feet of ditch and slopes. ditches.
Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all sediment
accumulation design depth. and debris so that it matches design.
Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation
constitute a hazard to County personnel or the removed according to applicable
public. regulations. No danger of noxious
vegetation where County personnel
or the public might normaily be.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Vegetation Vegetation that reduces free movement of water Water flows freely through ditches.
through ditches.
Erosion damage to Any erosion observed on a ditch slope. Slopes are not eroding.
slopes
Rock lining out of One layer or less of rock exists above native soil Replace rocks to design standards.
place or missing(If area 5 square feet or more,any exposed native
Applicable) soil.
2009 Surface Water Design�fanual—Appendix A 1i9i2009
A-11
IAPPENDIX A NIAINTENANCE REQUIREMENTS FLOVJ CONTROL,CONVEYA��ICE,AND WQ FACILITIES
' NO. 7- DEBRIS BARRIERS (E.G., TRASH RACKS)
Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When
Component Maintenance is Performed.
' Site Trash and debris Trash or debris plugging more than 20%of the Barrier clear to receive capacity flow.
area of the barrier.
Sediment Sediment accumulation of greater than 20%of Barrier clear to receive capacity flow.
' accumulation the area of the barrier
Sfructure Cracked broken or Structure which bars attached to is damaged- Structure barrier attached to is
loose pipe is loose or cracked or concrete structure is sound.
cracked,broken of loose.
' Bars Bar spacing Bar spacing exceeds 6 inches. Bars have at most 6 inche spacing.
Damaged or missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more
bars than 3/<inch.
' Bars are missing or entire barrier missing. Bars in place according to design.
Bars are loose and rust is causing 50% Repair or replace barrier to design
deterioration to any part of barrier. standards.
�
'
lr`9/2009 2009 Surface Water Design Manual—Appendix A
A-12
IAPPENDIX A I�4AINTENANCE REQUIREM�„I�TTS FLO�V CONTROL,CONVEYANCE,AI�TD WQ FACILITIES
INO. 9-FENCING
Maintenance Defect or Problem Conditions When Maintenance is Needed Resufts Ezpected When
Component Maintenance is Performed
' Site Erosion or holes Erosion or holes more than 4 inches high and 12- No access under the fence.
under fence 18 inches wide permitting access through an
opening under a fence.
' Wood Posts,Boards Missing or damaged Missing or broken boards,post out of plumb by No gaps on fence due to missing or
and Cross Members parts more than 6 inches or cross members broken broken boards,post plumb to within
1%2 inches,cross members sound.
Weakened by rotting Any part showing structural deterioration due to All parts of fence are structurally
' or insects rotting or insect damage sound.
Damaged or failed Concrete or metal attachments deteriorated or Post foundation capable of
post foundation unabie to support posts. supporting posts even in strong
' wind.
Metal Posts,Raiis Damaged parts Post out of plumb more than 6 inches. Post plumb to within 1%inches.
and Fabric
Top rails bent more than 6 inches. Top rail free of bends greater than
' 1 inch.
Any part of fence(including post,top rails,and Fence is aligned and meets design
fabric)more than 1 foot out of design alignment. standards.
Missing or loose tension wire. Tension wire in place and holding
' fabric.
Deteriorated paint or Part or parts that have a rusting or scaling Structurally adequate posts or parts
protective coating condition that has affected structural adequacy. with a uniform protective coating. I
' Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50%of
diameter ball could fit through. grid size.
�
�
1/9/2009 20�9 Surface�'��ater Desian 1�4anual—Appendix�
A-14 �
� APPEivDIX A MAINTENAIvCE REQUIItEb•fE�ITS FOR FLOW CONTROL,COi�IVEY.A��10E,r�ND WQ FACILITIES
I N0. 10-GATES/BOLLARDS/ACCESS BARRIERS
Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When
Component Maintenance is Perfortned
' Chain Link Fencing Damaged or missing Missing gate. Gates in place.
Gate members
Broken or missing hinges such that gate cannot Hinges intact and lubed.Gate is
be easily opened and closed by a maintenance working freely.
' person.
Gate is out of plumb more than 6 inches and Gate is aligned and vertical.
more than 1 foot out of design alignment.
� Missing stretcher bar,stretcher bands,and ties. Stretcher bar,bands,and ties in
place.
Locking mechanism Locking device missing,no-functioning or does Locking mechanism prevents
does not lock gate not link to all parts. opening of gate.
' Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50%of
diameter ball could fit through. grid size.
Bar Gate Damaged or missing Cross bar does not swing open or closed,is Cross bar swings fully open and
' cross bar missing or is bent to where it does not prevent closed and prevents vehicle access.
vehicle access.
Locking mechanism Locking device missing,no-functioning or does Locking mechanism prevents
does not lock gate not link to all parts. opening of gate.
� Support post Support post does not hold cross bar up. Cross bar held up preventing vehicle
damaged access into facility.
Bollards Damaged or missing Bollard broken,missing,does not fit into support No access for motorized vehicles to
' hole or hinge broken or missing. get into facility. I
Does not lock Locking assembly or lock missing or cannot be No access for motorized�ehicles to
attached to lock bollard in place. get into facility. ,
� Boulders Dislodged Boulders not located to prevent motorized vehicie No access for motorized vehicles to
access. get into facility.
Circumvented Motorized vehicles going around or between No access for motorized vehicles to
boulders. get into facility.
�
2009 Surface�'�'ater Design Manual—Appendix A L`9/2009
A-1�
� APPENDIX A MAINTENANCE REQUIREA�NTS FLO��CONTROL,CONVEYANCE,AIvD WQ FACILITTES
� NO. 11 -GROUNDS (LANDSCAPIIVG)
Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When
Component Maintenance is Performed
' Site Trash or litter Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site.
per 1,Q00 square feet(this is about equal to the
amount of frash it would take to fill up one
standard size office garbage can). In general,
� there should be no visual evidence of dumping.
Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation
constitute a hazard to County personnel or the removed according to applicable
� public. regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
' poilution as oil,gasoline,concrete slurries or paint. according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
' Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a
height. height no greater than 6 inches.
Trees and Shrubs Hazard Any tree or limb of a tree identified as having a No hazard trees in facility.
potential to fall and cause property damage or
� threaten human life. A hazard tree identified by
a qualified arborist must be removed as soon
as possible.
' Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than 5% '
broken which affect more than 25°/a of the total of total foliage with split or broken
foliage of the tree or shrub. limbs.
Trees or shrubs that have been blown down or No blown down vegetation or
knocked over. knocked over vegetation. Trees or
shrubs free of injury.
Trees or shrubs which are not adequately Tree or shrub in place and
supported or are leaning over,causing exposure adequately supported;dead or
� of the roots. diseased trees removed.
I�—i
i
�'�-
j
,
L_!
1/9/2009 2009 Surface Water Design Manual—Appendix A
A-16
I APPENDIX A MAINTENAI�TCE REQUIltEMENTS FOR FLO�V CONTROL,CONV"LYA.�ICE;:�D«�Q 1=.�CILITIES
I
� N0. 12-ACCESS ROADS
Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When
Component Maintenance is Perfortned
� Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway drivable by maintenance
square feet(i.e.,trash and debris would fill up vehicles.
one standards size garbage can).
� Debris which could damage vehicle tires or Roadway drivable by maintenance
prohibit use of road. vehicles.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations_
� Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Blocked roadway Any obstruction which reduces clearance above Roadway overhead clear to 14 feet
� road surface to less than 14 feet. high.
Any obstruction restricting the access to a 10-to At least 12-foot of width on access
12 foot width for a distance of more than 12 feet road.
or any point restricting access to less than a 10
' foot width.
Road Surface Erosion,settlement, Any surFace defect which hinders or prevents Road drivable by maintenance
potholes,soft spots, maintenance access. vehicles.
� ruts
Vegetation on road Trees or other vegetation prevent access to Maintenance vehicles can access
surface facility by maintenance vehicles. facility.
� Shoulders and Erosion Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and
Ditches inches wide and 6 inches deep. matching the surrounding road.
Weeds and brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inches in
hinder maintenance access. height or cleared in such a way as to
allow maintenance access.
Modular Grid Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
Pavement pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations.
Source control BMPs implemented if
� appropriate. No contaminants I
present other than a surtace oil film. ;
Damaged or missing Access surface compacted because of broken on Access road surface restored so
missing modular block. road infiltrates_
2009 Surface Water Design Manual—Appendix A 1/9/2009
A-17
APPEI�,'DIX:� 1�1.�TE�;:1I`CE REQUIRE1�fENTS FLO��J CONTROL,CO�IVEYAVCE,�1ND��%Q FACILITIES I
NO. 20-SAND FILTER V�4ULT I�I
Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When �
Component Maintenance is Performed !
Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from I
facility site.
Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation
constitute a hazard to County personnel or the removed according to applicable '
public. regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of
pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants ,
present other than a surface oil film. ',
Grass/groundcover Grass or groundcover exceeds 18 iriches in Grass or groundcover mowed to a I!
height. height no greater than 6 inches. I
Pre-Treatment Sediment Sediment accumulation exceeds the depth of the Sediment storage contains no
Chamber accumulation sediment zone plus 6 inches. sediment.
Sand Filter Media Sediment Sediment depth exceeds%z-inch on sand filter Sand filter freely drains at normal
accumulation media. rate. '
Trash and debris Trash and debris accumulated in vault(floatables No trash or debris in vauft.
and non-floatables).
Plugging Drawdown of water through the sand fiRer media, Sand filter media drawdown rate is
takes longer than 24 hours,andJor flow through normal. ,
the overflow pipes occurs frequ2ntly. A sieve �
analysis of>4%-100 or>2%-200 requires
replacing sand filter media.
Short circuiting Seepage or flow occurs along the vault walls and Sand filter media section re-laid and
corners. Sand eroding near inflow area. compacted along perimeter of vault
Cleanout wyes are not watertight. to form a semi-seal. Erosion
protection added to dissipate force ,
of incoming flow and curtail erosion. �
Vault Structure Damaged to walls, Cracks wider than Y=-inch,any evidence of soil Vault replaced or repaired to provide
frame,bottom and/or entering the structure through cracks or qualified complete sealing of the structure.
top slab. inspection personnel determines that the vauit is
not structuralty sound. I
Ventilation Ventilation area blocked or plugged. No reduction of ventilation area
exists.
Underdrains and SedimenUdebris Underdrains or clean-outs partially plugged,filled Underdrains and ciean-outs free of
Cleanouts with sediment and/or debris or not watertight. sediment and debris and sealed.
InIeUOutlet Pipe Sediment Sediment filling 20%or more of the pipe. Inlet/outlet pipes ciear of sediment.
accumulation
Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes.
pipes(inciudes floatables and non-floatables).
Damaged Cracks wider than'/rinch at the joint of the No cracks more than%4-inch wide at
inleUoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe.
at the joints of the inleUoutlet pipes.
1/9/2009 2009 Surface 1'�'ater Design 1-fanual—Appendix A
A-23
APPENDIX A MAINTENANCE REQUIREMENTS FOR FLO��'CONTROL,C0�1VEY��ICE,�D��'Q FACILITIES
NO. 20-SAND FILTER VAULT
Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When
Component Maintenance is Performed
Access Manhole CoverAid not in place Covedlid is missing or only partially in place. Manhole access covered.
Any open manhole requires immediate
maintenance.
Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools.
not working maintenance person with proper tools.Bolts
cannot be seated. Self-locking covedlid does not
work.
Cover/lid difficult to One maintenance erson cannot remove
P Cover/lid can be removed and
remove cover/lid after applying 80 Ibs of lift. reinstalled by one maintenance
person.
Ladder rungs unsafe Missing rungs, misalignment,rust,or cracks. Ladder meets design standards.
Allows maintenance person safe
access.
Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it
doors/plate to open opened/removed using normal equipment. can opened as designed.
Gaps,doesn't cover Large access doors not flat and/or access Doors close flat and covers access
completely opening not completely covered. opening completely.
Lifting Rings missing, Lifting rings not capable of lifting weight of door Lifting rings su�cient to lift or
rusted or plate. remove door or plate.
3009 Surface�T��ater Design A�1anua1—Appendix A � I r'9i2009
a-29
APPENDIX A MAINTENAIvCE REQUIItEMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES
NO. 24-CATCH BASIN INSERT
Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When
Component Maintenance is Performed
Media lnsert �sible Oil Visible oil sheen passing through media Media inset replaced.
Insert does not fit Flow gets into catch basin without going through All flow goes through media.
catch basin property media.
Filter media plugged Filter media plugged. Flow through filter media is normal.
Oil absorbent media Media oii saturated. Oil absorbent media replaced.
saturated
Water saturated Catch basin insert is saturated with water,which inseR replaced.
no longer has the capacity to absorb.
Service life exceeded Regular interval replacement due to typical Media replaced at manufacturer's
average life of inedia insert product,typically one recommended interval.
month.
Seasonal When storms occur and during the wet season. Remove,clean and replace or install
maintenance new insert after major storms,
monthly during the wet season or at
manufacturer's recommended
interval.
II
,I � .
� � ,`
,
i I .
I' ,
I j
2009 Surface Water Design Manual—Appendix A 1/9/2009
A-35
I
APPENDIX "D" CSWPPP '
I
O 2013 D.R.STRONG Consulting Engineers Inc. 51 Saddlebrook Div. II
Technical Information Report Renton,Washington
STORMWATER POLLUTION PREVENTION PLAN
For I
SADDLEBROOK DIV. II
Prepared For
Northwest Regional Office
3190 160th Avenue SE
Bellevue, WA 98008-5452
425-649-7000
Owner Developer Operator/Contractor
ACH Homes, LLC ACH Homes, LLC Maher A. Joudi, P.E.
9675 SE 36th Street Suite 105 9675 SE 36th Street Suite 105 620 7th Avenue
Mercer Island, Washington Mercer Island, Washington Kirkland, Washington 98033
98040 98040
Project Site Location
13422 156th Avenue SE, Renton, Washington
Certified Erosion and Sediment Control Lead
Justin Lagers
253.405.5587
SWPPP Prepared By
D.R. Strong Consulting Engineers, Inc.
620 7th Avenue
Kirkland, Washington 98033
Maher A. Joudi, P.E., Senior Project Engineer
SWPPP Preparation Date ��
August 7, 2013 ''
Approximate Project Construction Dates �'
Start Date: August 2013
End Date: December 2013
C 2013 D.R.STRONG Consulting Engineers Inc. i
STORMWATER POLLUTION PREVENTION PLAN
TABLE OF CONTENTS �'
1.0 INTRODUCTION.......................................................................................................1 I
2.0 SITE DESCRIPTION .................................................................................................3 i
2.1 Existing Conditions............................................................................................3 I
2.2 Proposed Construction Activities.......................................................................3 I
3.0 CONSTRUCTION STORMWATER BMPS ...............................................................5 I
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...............................................................9
3.1.8 Element#8 — Stabilize Channels and Outlets............................................9
3.1.9 Element#9 — Control Pollutants............................................................... 10
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
3.2 Site Specific BMPs.......................................................................................... 13
3.3 Additional Advanced BMPs............................................................................. 13 ,
4.0 CONSTRUCTION PHASING AND BMP IMPLEMENTATION................................14 '
5.0 POLLUTION PREVENTION TEAM.........................................................................15
5.1 Roles and Responsibilities .............................................................................. 15 I
5.2 Team Members............................................................................................... 15
6.0 SITE INSPECTIONS AND MONITORING ..............................................................16 I
6.1 Site Inspection................................................................................................. 16
6.1.1 Site Inspection Frequency........................................................................ 16 ,I
6.1.2 Site Inspection Documentation................................................................. 16 �
6.2 Stormwater Quality Monitoring........................................................................ 17
6.2.1 Turbidity Sampling......................................................................................... 17 ��
6.2.2 pH Sampling.................................................................................................. 17
6.2.3 Temperature Monitoring........................................................................... 18 'I
7.0 REPORTING AND RECORDKEEPING..................................................................19
7.1 Recordkeeping ................................................................................................ 19 I�
7.1.1 Site Log Book........................................................................................... 19 �
7.1.2 Records Retention ................................................................................... 19
;s 2013 D. R.STRONG Consulting Engineers Inc. Page i of ii
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013 I
�
7.1.3 Access to Plans and Records .................................................................. 19
7.1.4 Updating the SWPPP............................................................................... 19
7.2 Reporting.........................................................................................................20
7.2.1 Discharge Monitoring Reports..................................................................20
7.2.2 Notification of Noncompliance..................................................................20
7.2.3 PermitApplication and Changes..............................................................20
Appendices
AppendixA— Site Plans................................................................................................21
Appendix B — Construction BMPs..................................................................................22
Appendix C —Alternative BMPs.....................................................................................23
Appendix D — General Permit........................................................................................24
Appendix E — Site Inspection Forms (And Site Log)......................................................25
Appendix F — Engineering Calculations.........................................................................32
Appendix A Site Plans
• Vicinity map (with all discharge points)
• Site plan with TESC measures
Appendix B Construction BMPs
• Possibly reference in BMPs, but likely it will be a consolidated list so that
the applicant can photocopy from the list from the SWMM.
Appendix C Alternative Construction BMP list
• List of BMPs not selected, but can be referenced if needed in each of the
12 elements
Appendix D General Permit
Appendix E Site Log and Inspection Forms
Appendix F Engineering Calculations
• Flows, ponds, etc...
O 2013 D. R.STRONG Consulting Engineers Inc. Page ii of ii
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
Stormwater Pollution Prevention Plan
1 .0 INTRODUCTION
This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the
NPDES stormwater permit requirements for the Saddlebrook Div. II residential project
located in Renton, Washington. The site is located at 13422 156th Avenue SE, Renton,
Washington. The proposed development consists of the construction of 3 single-family
dwelling units, frontage improvements, and landscaping on 0.89 acres.
Construction activities will include, grading, roadway construction, utility installation and
home construction. 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 on July 2, 2005. This SWPPP was prepared based on the
requirements set forth in the Construction Stormwater General Permit, Stormwater
Management Manual for Western Washington (SWMMWW 2005) and in the
Stormwater Management Manual for Eastern Washington (SWMMEW 2004). 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.
• 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 (SWMMEW 2004).
• 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.
O 2013 D.R.STRONG Consulting Engineers Inc. Page 1 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
�- Stormwater Pollution Prevention Plan
i
i
' • 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
�s 2013 D.R.STRONG Consulting Engineers Inc. Page 2 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
Stormwater Pollution Prevention Plan
2.0 SITE DESCRIPTION
2.1 Existing Conditions
Total existing Site area is approximately 38,715 s.f. (0.89 ac). Total proposed Project
area is 41,095 s.f. (0.94 ac) which includes 2,380 s.f. (0.05 ac) for the right-of-way
frontage improvements on 156th Avenue SE. The existing parcel (366450-0250) is
currently developed with a single-family home, covered patio and a gravel driveway.
The remainder of the Site is lawn, landscaping, and scattered trees.
The 0.89 acre parcel contains a single natural discharge point near the southwest
corner of the Site. The Site sheet flows towards the southwest corner of the Site and
into the right-of-way. From there, it is collected into the conveyance system within 156t"
Avenue and is conveyed south.
For the purpose of hydrologic calculations, the entire Site is modeled as till forest.
2.2 Proposed Construction Activities
The applicant has gained approval to subdivide 0.89 acres into three single-family
residential lots (Project), with lot sizes ranging from approximately 10,169 to 10,983 s.f.
All existing improvements will be demolished or removed during plat construction. The
proposed impervious surface area will include a new shared driveway tract with 16 feet
of pavement. Impervious surFace are will also include offsite half-street improvements
along 156th Avenue SE. The proposed shared driveway improvements total
approximately 4,411 s.f. The three single-family residences and their driveways
combined will create approximately 10,875 s.f. of impervious area (reduced from
maximum allowable, see next paragraph for details). Post-developed impervious areas
including driveways, roofs, and site frontage improvements total approximately 17,666
s.f. (includes Bypass area). The remainder of the Project will be modeled as till grass
totaling approximately 23,429 s.f.
Per the 2009 King County Surface Water Design Manual (Manual), Appendix C, each
lot within a new subdivision is required to mitigate for impervious surface area equal to
10% of the lot area. Per Figure C.1.3.A, Flow Control BMP Flowchart, the Project will
utilize Basic Dispersion with the use of splash blocks. Two splash blocks mitigating a
total of 1,400 s.f. of impervious area, will be installed with each residence. This shall ,
mitigate for 12.75% to 13.77% of impervious area for each lot. Also, each lot will be
restricted to an area less than 4,000 s.f. (see table below). Additionally, use of Basic
Dispersion allows for a 50% flow control BMP sizing credit which was used in detention
facility calculations. See table below for lot area, restricted impervious area per lot, and
percent impervious mitigated per lot.
ROOF AREA ROUTED TO RESTRICTED IMPERVIOUS TOTAL AREA PERCENT IMPERVIOUS I�
LOT NO. LOT AREA(S.F.) SPLASH BLOCK(S.F.) AREA PER LOT MITIGATED MITIGATED
1 10169 1400 3505 1895 18.64
2 10983 1400 3485 1915 17.44 I
3 10877 1400 3885 1515 13.93 �!
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All surface water runoff from impervious surFaces will be collected and conveyed to a
storm detention pond located within Tract "A of Saddlebrook Div. I. From there, the
water runoff will be conveyed through a BayFilter vault before entering the existing
conveyance system within 156th Avenue SE.
The following summarizes details regarding site areas:
• Total site developable area: 0.89 acres
• Percent impervious area before construction: 7.4 % ,
• Percent impervious area after construction: 45.7 %
• Disturbed area during construction: 0.94 acres
• Disturbed area that is characterized as impervious
(i.e., access roads, staging, parking): 0.13 acres
'�, � TDA
• 2-year stormwater runoff peak flow prior to construction (existing): 0.029 cfs
• 10-year stormwater runoff peak flow prior to construction �-�xisting): 0.047 cfs
• 2-year stormwater runoff peak flow during construction: 0.214 cfs ,
• 10-year stormwater runoff peak flow during construction: 0.338 cfs II
� • 2-year stormwater runoff peak flow after construction:
0.083 cfs (Combined detention facility with Saddlebrook Div. I)
• 10-year stormwater runoff peak flow after construction:
0.228 cfs (Combined detention facility with Saddlebrook Div. I)
� All stormwater flow calculations are provided in Appendix F.
�
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3.0 CONSTRUCTION STORMWATER BMPS
3.1 The 12 BMP Elements I
3.1.1 Element#1 — Mark Clearing Limits ',
To protect adjacent properties and to reduce the area of soil exposed to construction, I�,
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. I
The BMPs relevant to marking the clearing limits that will be applied for this project ,
include:
• High Visibility Plastic or Metal Fence (BMP C103)
The plastic fence will be placed around the perimeter of the developable area of the
Site. BMP will be implemented at the start of construction.
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 I
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)
• Construction RoadlParking Area Stabilization (BMP C107) '
A Stabilized Construction Entrance will be placed at the intersection of, the proposed '
road, "Road A" and 156th Avenue SE. This BMP will be implemented at the start of
construction.
Construction Road and Parking Area Stabilization will occur along the road into the site
and in staging areas where parking of equipment will occur. This will occur as the �,
project goes along. I
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
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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.
3.1.3 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:
• Sediment Trap
A sediment trap will be installed in Lot 1.
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:
• Silt Fence (BMP C233)
• Storm Drain Inlet Protection (BMP C220)
• Interceptor Swale (BMP C200)
• Sediment Trap
Silt fence will be installed around the perimeter of the Site in areas where runoff could
sheet-flow offsite. This BMP will be installed at the start of construction.
Storm Drain Inlet Protection will be installed on all newly constructed catch basins
throughout the site as well as the existing catch basins in 156t" Avenue SE. The
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existing catch basin protection will be installed at the start of construction, and
protection for the newly constructed catch basins will occur as they are installed.
The interceptor swales will be installed during site grading.
The sediment trap will be installed and used for sedimentation at the commencement of
construction.
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 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 once the remainder of the site has been
stabilized.
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.
• 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:
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• Temporary and Permanent Seeding (BMP C120)
• Plastic Covering (BMP C123)
• Dust Control (BMP C140)
Permanent Seeding will occur as grading is completed. All stabilized sections will be
seeded and �egetated.
Plastic Covering will occur throughout the site as deemed necessary by the contractor
and CESCL.
Dust Control will occur throughout the site as deemed necessary by the contractor and
CESCL.
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 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.
i , 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)
• Check Dams (BMP C207) ;
Permanent Seeding will occur throughout the site as slopes are stabilized. '
Checks Dams will be installed every 50' as shown on the plan.
jAlternate 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
I ' 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
I
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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:
Drop Inlet Protection
• Catch Basin Filter
There is one existing catch basin which will require a filter within 156t" Avenue SE.
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 implemented
The project will not discharge to any outlets or channels; therefore no BMP's are
required.
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,
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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.
Vehicles, construction equipment, andlor 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.
Solid Waste:
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• Solid waste will be stored in secure, clearly marked containers.
Other:
• Other BMPs will be administered as necessary to address any additional
pollutant sources on site.
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 '�
There will be no dewatering as part of this construction 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.
• 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:
(West Response) 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
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_ • The construction project is being phased to the e�ent practicable in order
to prevent soil erosion, and, to the maximum extent possible, the transport
I � ', 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:
o Site conditions including existing vegetative coverage, slope, soil type,
and proximity to receiving waters; and
o Limitations on activities and the extent of disturbed areas; and
o 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:
o Routine maintenance and necessary repair of erosion and sediment
control BMPs;
o 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
o 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:
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o Assess the site conditions and construction activities that could impact
the quality of stormwater, and
o 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 I
discharge a significant amount of any pollutant, appropriate BMPs or '
design changes shall be implemented as soon as possible. li
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.
• 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.
If 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.
3.2 Site Specific BMPs
Site specific BMPs are shown on the TESC Plan Sheets and Details in Appendix A.
These site specific plan sheets will be updated annually.
3.3 Additional Advanced BMPs
None Proposed
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4.0 CONSTRUCTION PHASING AND BMP IMPLEMENTATION
The BMP implementation schedule will be driven by the construction schedule. The I
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: 9/2/2013
• Estimate of Construction finish date: 10/1/2013
• Mobilize equipment on site: 9/2/2013
• Mobilize and store all ESC and soil stabilization products: 9/3/2013 - 9/6/2013
• Install ESC measures: 9/3/2013 - 9/10/2013
• Install stabilized construction entrance: 9/3/2013
• Begin clearing and grubbing: 9/11/2013 — 9/18/2013
• Demolish existing buildings: 9/11/2013 — 9/18/2013
• Begin Site Grading: 9/20/2013
• Begin implementing soil stabilization and .
sediment control BMPs throughout the site: 9/19/2013
• End Site Grading: 10/18/2013
• Begin Utility Construction: 10/21/2013
• End Utility Construction: 11/25/2013
• Begin Paving and Sidewalk Installation: 12/2/2013
• Permanent erosion control measures (hydroseeding): 12/10/2013
• End Paving and Sidewalk Installation: 12/13/2013
• Final landscaping and planting begins: 12/14/2013 '
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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
re resentative of the site owner
p 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 Justin Lagers 253.405.5587
Lead(CESCL)
Resident Engineer MaherA.Joudi 425.827.3063
Emergency Ecology Contact NW Regional Office 425.649.7000
Emergency Owner Contact Justin Lagers 253.405.5587
Non-Emergency Ecology Contact Ken Waldo 425.649.7279
Monitoring Personnel TBD
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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 will be maintained on-site or within reasonable access to the site
and be made available upon request to Ecology or the local jurisdiction.
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6.2 Stormwater Quality Monitoring
The Site will discharge into an existing storm drainage system. Before project
discharge leaves the Site, it enters a detention pond which outlets into a BayFilter vault
before entering the existing conveyance system located within 156th Avenue SE. This
will be sufficient in accommodating water quality requirements. Testing at the outlet will
still occur as necessary.
6.2.1 Turbidity Sampling
Sampling and monitoring will be conducted during the entire construction phase of the
project. Samples will be collected daily at the downstream catch basin for both the
pond and vault. If there is no flow in this catch basin, the attempt to sample will be
recorded in the site log book and reported to Ecology in the monthly Discharge
Monitoring Report (DMR) as "No Discharge". Samples will be analyzed for turbidity
using the EPA 180.1 analytical method.
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 the tested catch basins, 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
Sampling and monitoring for pH will occur during the phase of construction when
concrete pouring will be conducted until fully cured (3 weeks from last pour) and
discharges are documented to be below pH 8.5. Samples will be collected weekly at
the sedimentation pond prior to discharge to surf'ace water. Samples will be analyzed
for pH using a calibrated pH meter and recorded in the site log book.
The key benchmark pH value for stormwater is a maximum of 8.5. If a pH greater than
8.5 is measured in the sedimentation trap/pond(s) that has the potential to discharge to
surFace water, the following steps will be conducted:
C�2013 D. R.STRONG Consulting Engineers Inc. Page 17 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
Stormwater Pollution Prevention Plan
1. Prevent (detain) all discharges from leaving the site and entering surFace
waters or storm drains if the pH is greater than 8.5
2. Implement CO2 sparging or dry ice treatment in accordance with Ecology
BMP C252.
Describe inspection results and remedial actions that are taken in the site log book and
in monthly discharge monitoring reports as described in Section 7.0 of this SWPPP.
6.2.3 Temperature Monitoring
No temperature monitoring is required for this construction site.
i
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O 2013 D.R.STRONG Consulting Engineers Inc. Page 18 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
_----- �I
Stormwater Pollution Prevention Plan '
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.
j 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 SS.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 SWPPR 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 'i
will be modified if the SWPPP is ineffective in eliminating or significantly minimizing j
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 I
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.
;�2013 D. R.STRONG Consulting Engineers Inc. Page 19 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7, 2013
Stormwater Pollution Prevention Plan
7.2 Reporting
7.2.1 Discharge Monitoring Reports
Water quality sampling results will be submitted to Ecology monthly on Discharge
Monitoring Report (DMR) forms in accordance with permit condition SS.B. If there was
no discharge during a given monitoring period, the form will be submitted with the words
"no discharge" entered in place of the monitoring results. If a benchmark was
exceeded, a brief summary of inspection results and remedial actions taken will be
included. If sampling could not be performed during a monitoring period, a DMR will be
submitted with an explanation of why sampling could not be perFormed.
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 SS.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.
Any time turbidity sampling indicates turbidity is 250 nephelometric turbidity units (NTU)
or greater or water transparency is 6 centimeters or less, the Ecology regional office will
be notified by phone within 24 hours of analysis as required by permit condition S5.A
(see Section 5.0 of this SWPPP for contact information).
In accordance with permit condition S4.F.6.b, the Ecology regional office will be notified
if chemical treatment other than CO2 sparging is planned for adjustment of high pH
water (see Section 5.0 of this SWPPP for contact information).
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.
O 2013 D. R.STRONG Consulting Engineers Inc. Page 20 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7, 2013
Stormwater Pollution Prevention Plan
APPENDIX A - SITE PLANS
4
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O 2013 D.R.STRONG ConsuRing Engineers Inc. Page 21 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
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f. iHF£SC fACICIT7E5 SHOWN ON R115 PLAN MVST BE CON57RUClED PRNA7 TO OR/N CON.NNC7ION YSM A.LL CLEAP•MG AND 6!'AD1NC 50 AS 70 �LL ARWNO 7NE 7REf. 7HE OlAKE7ER Of IHIS WACL OR NELL YUST BE EIX/AL 70 7HE TR£E5 P41P LINE. �'
� r, fNSURf INAT THE TRA/.SPORT OF SEDINfN7 TO SURfACE W.17ER$ORF/NAG£SKTEY$ANO AD.IACEN7 PR�ERTrES/5 M/NMl7£D.
C IMPERVIOUS SURfAC£S PRQ+I!&7f0 YATNlN RiE ORIP LINf: 1X£APPLICAN7 NAY 0.�OT IA�'SiALL lNPERNWS SURFAC£MA7fR41L N9/H/N TNE AREA DEFA'ED BY TH£DR/P LlNf OF ANY
5 THf£SC fAGL/Tl£5 SHGMN QV RfiS P2AN ARE THE WN/YUN REOfAR£71dENT5 FOR ANAUPAIEO SITE COhD/710NS OUR/NG 7HE CONSTRUCTION TREE TO BE RETA/NED.
PERI00. 7HfSE£SC fACWAES SHALL B£UPGRAOED AS AiEEDfO FQR UfrEXP£CTE'D SiOR.V ElEN75 AND.IlOD61E0 TO ACCOUN7 FQP CHANpNC 5/7E �
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-I I.-��I + i GOLLONfNG AR£AS(!)AiF AREA D£FPIED BY IHE OAN L!N£6�h/E 7RE£,Cu4(/l)A1J AREA AFOU.MD THE 7REE EOUAL TO ON£AND QNE-HALF FEE7(i-7/7 J LV LlAf1E7ER FOR FACH '
�'�.I=I I I��I�I,I''.I I � 6. THF£SC fAGt17/f5 SHA[L BE MSPECIEO DA2Y BY THE MP[IGNT/FSC SUPERNSOR AND YA/NTAINEO TO ENSUPE CQVTMMIED PROPER 01�£INLH OF 7REE CALlPER. RfE REV]EW1NG GFFIOAL LAY REOUlR£A LARt{R 7RfE PROffCiION ZOh'E BASEO OIJ 7REE 9ZE,SPEpE$SQ'C,OR D7HER LONDlTIONS
-I I I=I I' I f7/NC110h'ING ItR1T7£N RfCORDS SrfALL 6E XEPT OF SYfEKLY R�WS OF M££SC(AC¢111E5 DYIRWG JNE MET SEASON(CL7. 1 TO APR2 30)AND
����I I�,I��-I I V OF bON771GY R£✓!EWS DUR.WC THE DAY SEASON IuAY 7 TO SEPT.30). L NULCH UYFR REIXJIR£D:A:1 Ar.fAS N17N/N 7HE R£WlRfO FENLYNG SHA1L 6f COVfRflJ C0117LETFLY hVD£VENLY IN7H A MN;1.fUN L1�R1REE lNCHfS(3 J Oi BAkK MULCH PRIOR 70 '
i Y- _ INSTPllAPCAf OF INE P1707EC7Ib£FENpNG.fXQ'PTONS YAY BE APPROl�EO BY TFif P.£V)£N1NC GFFILUL If 7HE IAULCif 1kL AC'hF5£LY AfFECT P.401ECTED GRO�JND COKR W_AN75.
-������� i��. .
- �I 1=��I 7. FNY APEAS OF EXPOS£0 SO/L5�INCLUDING ROADWAY FUHANKMENTS, 7HAT N1LL NO7 BE 06TUP.8ED FOR TN17 DAYS CJP,JNC R1£Wf7 SfASLW 9 yq,pJppnyC AEO!/IRED DURINC CONS7RUCTIOM R1E APPUCANT SHALL R£TA/N A PROfESSiONAL ARBO.R;ST OP.OiHER G'✓AL�r;fO PROFFSSlOA'AL TO P.4'J4E BR<NM�S A4'D R007$
=�'�I,=„I_I= pg SfL£N DAY$DURMG THE ORY SFASON SHALL 6E LbME0lA7E[Y STABIL2f0 Mf1N 7HE APPR04ED£SC AlEMOOS(EG,SEEDIh'f�,MULpiI,YG PLASTIC
COYERM'Cy ETC.). fER7M17E,AND WAiER AS APPROPRIAIf FOR ANY 7RfE5 ANO GRO!/ND C04£R NHIGY ARE TD BE RETAINEO.
fl ANY AR£A NEEDA'C ESC NEASURES NOT R£OUfR.MlGlMMfDIA1E A7TENTbN SNiL'i EE ADDRESSEO NIR1/N F/FTE'EN(ISJ OAYS �
9. 1NE ESC FAL/UIIES ON WAC7/VE 5l7f5 SHALL BF/NSPEC7ED AND LUINTA.'NED A 14%IUL'M OF CNCE A MLWRi OR NfMIN FORTY-EIGHT(S8J
. ccnortpwoFus¢ HOURS FOCLONVJG A STORM EL£NT. '�
. aoMpsrv�ae=�•.-usmru+oma.�=onvsGRi4�s �O. AT NO TG(E$HAlL NCRE TiIAN OIJE 1 FOOT Q�SfA'1(EN7 E£ALLOKO TO ACCUAIIlLA1E YAiNIN A GTCH BAS/N. ACL CATCH BAS7N5 AIJD
12. TC O�FVEVFI'vOFFIN'9tCFFTFDFRWuuqsi�'xa�w�2=.t5MC.ubTHE91[TO0.xOnmasR'[q�'xG_PON�. �� �.
- CQYYEYANCE CINES SHA[L BE CLEANED PRfOR 70 PANNG TN£CLEA4/NC OPfRAT10N SHALL N07 FLUSN 5£O/AIENT-LAOEN WAlER MTO THE '
naixreu..rvcesr..xw.nvs �Ot4N5TR£FY SY57fl( I
z.i. •:SmM+En'ic_Fcs:norvoFv-atETW�HcscEFrvf,�aiE_a=_uo�£nsorxnrr-ecn<wvEisr�srw.Eomrrsc.ic�au �I
auC�cpnv. il. STABICIZED CONS7RVCTlLN ENTRAh'CFS AND ROADS SHALL Bf ASTALLED AT THE HEGINNLNG 0.�LLW57RUCPON/ND 11AIN7AlNED�OR 7H£ '
��� ��uso�ceuF-��w=�r��=�ssrv�uae�ararze�Eoariw�ee��s�oxovr�smnueeanas�-s�oua:�:cu:=e.��vcr CUAATION OF 7i!E PROF_CT. ADDIP,OVUL bEASURf�SUpI AS Wl�SH PPOS MAY Bf REW/RED TO ENSURE THAT f.li PALED ARfAS ARf X£P7 I
..-. ..- Er+,'r5ic�c�eurv:�.Er_ CLEAN FOP IN£DURA7/ON Q�THE PRQ�ECT. I
12 ANY PERMANfNT fLOW CQNIFOL�AC217Y USED AS A 7ENPQRARY SETRINC BASfN SHALL BE NOD/FlED MiTH THE NEC£SSARY FROS101/CONT?OL I
NEASURES AND SHALL PRONDE ADEOUATE STO.RAGE GPAG7Y. IF THE fACICITY IS 70 FUNC710N UL70.IATQY AS AN INFM I.PA110N SYSTCM, 7HE A'OTES. ��
7[MPORARY FAbLlTY!lUST 8E GRADEO 50 7HA7 11iE BOTlOY ANO$ICES ARE A7 LEA57 THREE FEF7 ABOVF 7HE FWAL GI7ADE Of ME PERYANEN7 ).E-FT.HIGH TfNPORARY CHA/N LINK F£NCE SNALL BE I
= FACIL/TY. PLACED AT IH£DRIPLluE CE�TH£TR£E TO B£SAV£D. FfNCE � I
- 11 YMfRF STRAW 1/VLCH fOR TEAIPORARY EROSION CQY7ROL 6 REplH7E0,IT SHALL B£APPLIED AT A M/:GVUTA 7HICKNESS Of 7 TO 3 MCHES. �F�CON.LE7ELY fNdRC�E TN£7R£E(5). INSiA(L FENCE I
_ PG575 L'9NG Pi£R BLOCYS OhiY. AVpD C.R;NNC P0575 OR
19. PRIOft TO THE BEGA"JN(NG OF Tr/E WET SEASON OCT. 1,ALL DISTURBED AP.fAS SHAl1 BE RENEN£D 7�IQ[TIPfY NMCH GVES CAN BE 5£EDEO S7AKE5 MTO AUJ0.4 ROGTS
C J 2 FOR RO0T5 OKR 1-fN OIA. 7NAT AP.F OALfAGED OURING
IN FREPA.4AA:1N fOR THE N4N7£R RA/NS DlSRlR9fD AREAS SMALC BF SEEDED WIIhPN(AYE W£EK OF 11fE dEG414WIJG OF THE lSET SEASON. A CpN57RUC710N,NAKE A CLEAN,STRAIGrl7 CUT TO R£MOVE 6'�;�y
SiCE7CN YAP OF THOSE AREAS TO B£SffOED ANO 7}/OSf AREAS 70 R£4�IN UNCOVFRED 57fALL BE SUB�MTIED TO IfIE OJES/MSPECTOR. 7HE THF OANAGEO POFnOAI. ALL EXP'JSfO ROOTS SHALL 8E
ODES WSPFCTOR CAN Rf0U1Rf SEEDING OF ADDITIO.NAL AREAS/N MOER TO PROIECT SURFACE NA7ER$AOJACENT PROP£RIIES Q4 ORA/NAGE TEAIPOP.ARICY COV£RED M17H DAMP BURLAP TO PREVENT I
fAC1UDE5 GRri.4G AND SHALL BE COVER£D N1TH 50/1 AS$DON AS I RECOMMENDED FOR APPOVAL
FCS578LE �
- 3. WORK fNR1M PRGTEC7fON F£NCE$lIALL EE OOh'E BY: Date:
1lANUA(LY. NO STOCXPNNG OF NArRUL$ IFHICUUR
S1D.PIAN-217.40 TRAFF7C OR STORAGF Ll�EOUMN£NT OR MF.CHDJERY SHALL BY: Date:
PUBLIC tt��I(S CHECK OAMS SPAGING AND p[A.LLOWfD NfTMN THE UN/I OF THE FENGNG.
- ����� DEPA.RI'MENP CROSSSECTIOPIS BY: Date:
�� 1L.P.CH 2:Od
- TREE PROTECAON DETAIL c.qrvcm:c o.e coc�nox BY: Date:
APPRO'+EO BY ARBORIST
tti 4QR: Jp uiS
oF ��.jdJ
��y CONSUL�NGENG/NEERS s,s �ns Noreo �' a'�°` �� CI ;Y ��F SADDLEBROOK DIV. II �oa.oa.is
_ Ca9 2 Workhg Deys Betare Yw Dig �F ~ x D � � �f� ��s
� ax�wmzs ruw,�rrs s��s � R E�l TO P� TESC NOTES AND DETAILS
811 �' @' .��
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O�,ur.FD,oR,WA7 �`c'oY„L£�' o�zs.ez7.so&'iv�a.e�7.aaza � .., .1z��, � �� F, C6
` N0. REVSID:J Bl' CATE .q?�R ""� - � ' � 6 "-.14
A -NNNNAA
APPENDIX B - CONSTRUCTION BMPS
High Visibility Plastic or Metal Fence (BMP C103)
Stabilized Construction Entrance (BMP C105)
Construction Road/Parking Area Stabilization (BMP C107)
Temporary and Permanent Seeding (BMP C120)
Plastic Covering (BMP C123)
Dust Control (BMP C140)
Materials on Hand (BMP C150)
Interceptor Swale (BMP C200)
Check Dams (BMP C207)
Storm Drain Inlet Protection (BMP C220)
- Silt Fence (BMP C233)
Sediment Trap
_
O 2013 D. R. STRONG Consulting Engineers Inc. Page 22 of 33
Storm�vater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
Stormwater Pollution Prevention Plan
�
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.
None Proposed
s 2013 D.R. STRONG Consulting Engineers Inc. Page 23 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7, 2013
APPENDIX D - GENERAL PERMIT
O 2013 D.R.STRONG Consulting Engineers Inc. Page 24 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2�13
APPENDIX E - SITE INSPECTION FORMS (AND SITE LOG) �,
The results of each inspection shall be summarized in an inspection report or checklist II',,
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 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'.
��2013 D. R.STRONG Consulting Engineers Inc. Page 25 of 33 ',
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7, 2013 'I
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.
; ,
�_� �
�--.
�_!
, �
f
O 2013 D.R.STRONG Consulting Engineers Inc. Page 26 of 33
' Stormwater Pollution Prevention Plan Saddlebrook Div.II August 7,2013
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 9: Mark Clearing Limits
BM P:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
i
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
Element 2: Establish Constructron Access
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
; BM P:
� Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
Element 3: Contro!Flow Rates
BMP:
Location Inspected Functioning Problem/Corrective Action
Y N Y N NIP
- �2013 D. R. STRONG Consulting Engineers Inc. Page 27 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
BMP:
Inspected Functioning '
Location Y N Y N NIP Problem/Corrective Action '
Element 4: Instal!Sediment Controls
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Location �nspected Functioning Problem/Corrective Action
Y N Y N NIP
i_
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
�
i BMP:
- Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Inspected Functioning
- Location Y N Y N NIP Problem/Corrective Action
Element 5: Stabrlize Soils
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BM P: III
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
O 2013 D. R.STRONG Consulting Engineers Inc. Page 28 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div.II August 7, 2013
�
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Location Inspected Functioning Problem/Corrective Action
Y N Y N NIP
Element 6: Profect Slopes
BMP:
_ - Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Inspected Functioning
Location Y N Y N NIP ProblemlCorrective Action
Element 7: Protect Drain lnlets
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
�
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
� :,2013 D. R. STRONG Consulting Engineers Inc. Page 29 of 33
Storm�vater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
�
Element 8: Sfabilize Channels and Outlets
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Inspected Functioning
Location Y N Y N NIP ProblemlCorrective Action
Element 9: Contro!Pollutants
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
BMP:
Inspected Functioning
Location Y N Y N NIP Problem/Corrective Action
E/ement 90: Control Dewafering
BMP:
Inspected Functioning '
Location Y N Y N NIP Problem/Corrective Action I
BM P:
Location InspYct N YunNionNIP Problem/Corrective Action
:�2013 D. R.STRONG Consufting Engineers Inc. Page 30 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013
BMP:
Inspected Functioning
Location Y N Y N NIP ProblemlCorrective Action
Stormwater Discharges From the Site
Observed? problemlCorrective Action
Y �N
Location
Turbidity
Discoloration
Sheen
Location
Turbidity
Discoloration
Sheen
Water Quality Monitoring
Was any water quality monitoring conducted? o 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:
O 2013 D.R.STRONG Consulting Engineers Inc. Page 31 of 33
Stormwater Pollution Prevention Plan Saddiebrook Div. II August 7,2013
APPENDIX F - ENGINEERING CALCULATIONS
G 2013 D. R. STRONG Consulting Engineers Inc. Page 32 of 33
Stormwater Pollution Prevention P�an Saddlebrook Div. II August 7, 2013
SEDIMENT TRAP SIZING
Modeling Input �
�Eand Use Summary
�Area� ?
i,
Till Forest O.OD acres�
I
Till Pasture� 0.00 acres
Till Grass 0.49 acres
Outwash Forest� 0.00 acres
Outwash Pasture 0.00 acres
i
Outwash Grass� 0.00 acres�
Wetlandl 0.00 acres
Imperviousl 0.45 acres
Total�
0.94 acresl
Scale Fador: 1.00 15-Min Reduced
Edit Flow Paths I
• - Time Series: dev »
Compute Time Series I
Modify User Input I
� Fle for computed Time Series[.TSFj
Modeling Results
Flow Frequency Analysis
Time Series File:dev.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates--- -----Flow Frequency Analysis-------
Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob
(CFS) {CFS) Period
0.214 6 8/27/O1 18:00 0.779 1 100.00 0.990
-- 0.164 8 1/05/02 15:00 0.513 2 25.00 0.960
0.513 2 12/08/02 17:15 0.338 3 10. 00 0.900
0. 172 7 8/23/04 14:30 0.306 4 5.00 0.800
0.338 3 11/17/04 5:00 0.271 5 3.00 0.667
0.271 5 10/27/05 10:45 0.214 6 2.00 0.500
0. 306 4 10/25/06 22:45 0. 172 7 1.30 0.231
0.779 1 1/09/08 6:30 0. 164 8 1. 10 0.091
Computed Peaks 0.690 50.00 0.980
The sediment trap requires 2,080 s.f. of surface area per cfs of inlow; developed 2-year
storm, 15-minute time steps.
Required SurFace Area = 2,080 x .214 = 445 s.f.
Provided Surface Area = 1,077 s.f.
O 2013 D.R.STRONG Consulting Engineers Inc. Page 33 of 33
Stormwater Pollution Prevention Plan Saddlebrook Div. II August 7,2013