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TECHNICAL INFORMATION REPORT
for
Wehrman Plat
King County Tax Parcel Nos.
619900-0101, & 332305-9010
Pre -application No.
Site Addresses:
122nd Avenue SE
between SE 188th Street and SE 192nd Street
Renton, Washington
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Prepared by: Lorna M. Taylor, P.E.
TEC Project No. 485-MW Date: February 29, 2012
485 Rainier Blvd N, Ste #142, P.Q. Box 1787 . Issaquah, Washington 98027 . telephone (425) 391-1415 • fax (425) 391-1551
Taylor
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jj- Engineering
41-Fi L -7 Consultants
TECHNICAL INFORMATION REPORT
for
Wehrman Plat
King County Tax Parcel Nos.
619900-0101, & 332305-9010
Pre -application No.
Site Addresses:
122nd Avenue SE
between SE 188th Street and SE 192"d Street
Renton, Washington
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Prepared by: Lorna M. Taylor, P.E.
isTEC Project No. 485-MVV Date: February 29, 2012
485 Rainier Blvd N, Ste #102, P.O Box 1787 • Issaquah, Washington 98027 . telephone (425) 391-1415 • fax (425) 391-1551
Technical Information Report
Wehrman Plat
TABLE OF CONTENTS
Section
Description Pane Number
1.
Project Overview ..........................................
1
2.
Conditions and Requirements Summary...........
1
3.
Off -Site Analysis ..........................................
6
4.
Flow Control and Water Quality Facility Analysis
andDesign ....................................................
7
5.
Conveyance System Analysis and Design........
9
6.
Special Reports and Studies .........................
9
7.
Other Permits ..... .........................................
9
8.
ESC Analysis and Design ..............................
9
9.
Bond Quantities, Facility Summaries, and
Declaration of Covenant ................................
10
10.
Operations and Maintenance Manual ...............
10
Appendices
Appendix A:
Figures
1. Technical Information Report (TIR) Worksheets
2. Site Location
3. Drainage Basins, Subbasins, & Site Characteristics
4. NRCS Soils Map
Appendix B:
Off -site Analysis Drainage System Table and Map
Appendix B-1:
Drainage Complaint Analysis
Appendix C:
Analysis and Design
Appendix C-1:
Detention Facilities Design
Appendix C-2:
Treatment Facilities Design
Appendix C-3:
Erosion Control Facilities Design
Appendix C-4:
Conveyance Facilities Design (pending)
Appendix D:
Maintenance Requirements for Privately Maintained Drainage
Facilities
Appendix E:
Bond Quantities Worksheets (pending)
Appendix F:
Retention/Detention Facility Summary Sheet and Sketch
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Technical Information Report
Wehrman Plat
SECTION 1
PROJECT OVERVIEW
This Technical Information Report is submitted to the City of Renton in accordance with the
City -adopted King County Surface Water Design Manual (KCSWDM) and the City of Renton
Amendments thereto (Renton Amendment), dated February, 2010. It addresses stormwater
runoff from the proposed Wehrman Plat, A "Level 1 Off -site Drainage Analysis and Preliminary
Detention Sizing Calculations Report", dated December 2, 2004, and revised November 9,
2005, was previously approved by King County for this project, and portions of that report are
referenced herein; however, the proposed plat layout has been modified and this TIR
addresses the currently -proposed plat layout.
The 6.74-acre Wehrman Plat site comprises 2 existing lots located at about 122nd Avenue SE,
between SE 188th Street and SE 192� Street in Renton, Washington. The project proposes to
subdivide the two lots into 30 residential lots, with almost all of the development proposed for
the western lot, and only some open space and parks proposed for the eastern lot. The project
will include the required infrastructure, including access roads, water and sanitary sewer
service, storm runoff collection, conveyance, detention and treatment, and erosion control
during construction.
The project is required to undergo Full Drainage Review in accordance with Figure 1.1.2.A of
the KCSWDM & Renton Amendment. Appendix A contains a Technical Information Report
(TIR) worksheet for the project (Figure 1), as well as a Site Location Map (figure 2), Drainage
Basins, Subbasins, and Site Characteristics figure (Figure 3), and a Soils map (Figure 4). More
detailed site information is included in Appendix C with the existing and developed site runoff
model data.
SECTION 2
CONDITIONS AND REQUIREMENTS SUMMARY
Following is the text of the King County Hearing Examiner's Preliminary Conditions of Approval,
dated August 10, 2006. All of the conditions 1 -- 17 either have been addressed, or will be
addressed for the project.
1. Compliance with all platting provisions of Title 19A of the King County Code.
2. All persons having an ownership interest in the subject property shall sign on the face of the final
plat a dedication that includes the language set forth in King County Council Motion No. 5952.
The plat shall comply with the base density and minimum density requirements of the R-6 zone
classification. All lots shall meet the minimum dimensional requirements of the R-6 zone
classification or shall be shown on the face of the approved preliminary plat, whichever is larger,
except that minor revisions to the plat which do not result in substantial changes may be approved
at the discretion of the Department of Development and Environment Services.
Any/all plat boundary discrepancy shall be resolved to the satisfaction of DDES prior to the
submittal of the final plat documents, As used in this condition, "discrepancy" is a boundary
hiatus, an overlapping boundary or a physical appurtenance which indicates an encroachment,
lines of possession or a conflict of title.
3. All construction and upgrading of public and private roads shall be done in accordance with the
King County Road Standards established and adopted by Ordinance No. 11187, as amended
(1993 KCRS).
4. The applicant shall obtain documentation by the King County Fire Protection Engineer certifying
compliance with the fire flow standards of Chapter 17.08 of the King County Code.
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5. Final plat approval shall require full compliance with the drainage provisions set forth in King
County Code 9.04. Compliance may result in reducing the number and/or location of lots as
shown on the approved preliminary plat. Preliminary review has identified the following conditions
of approval which represent portions of the drainage requirements. All other applicable
requirements in K.C.C. 9.04 and the Surface Water Design Manual (SWDM) must also be
satisfied during engineering and final review.
a. Drainage plans and analysis shall comply with the 1998 King County Surface Water Design
Manual and applicable updates adopted by King County. DDES approval of the drainage and
roadway plans is required prior to any construction.
b. Current standard plan notes and ESC notes, as established by DDES Engineering Review,
shall be shown on the engineering plans.
c. The following note shall be shown on the final recorded plat:
"All building downspouts, footing drains, and drains from all impervious surfaces such as
patios and driveways shall be connected to the permanent storm drain outlet as shown on the
approved construction drawings # on file with DDES and/or the King County
Department of Transportation. This plan sha€€ be submitted with the application of any
building permit. All connections of the drains must be constructed and approved prior to the
final building inspection approval. For those lots that are designated for individual lot
infiltration systems, the systems shall be constructed at the time of the building permit and
shall comply with plans on file."
d. The drainage detention facility shall be designed to meet at a minimum the Level 2 Flow
Control and Basic Water Quality menu in the 1998 King County Surface Water Design Manual
(KCSWDM).
e. Storm drain stubs for future connection shall be provided along the west property line in
general conformance with the Preliminary Grading and Storm Drainage Plan received April
19, 2006, unless otherwise approved by DDES.
The applicant's geotechnical engineer shall provide recommendations for the design and
construction of the proposed site grading, road design, rock or retaining walls and drainage
detention facility design. The geotechnical engineer shall evaluate the site for potential
groundwater seeps and provide design recommendations to address groundwater found.
The geotechnical recommendations shall be included in the T.I.R. and incorporated into the
design with submittal of the engineering plans.
g. Special geotechnical construction inspection of the site grading, road construction, rock or
retaining walls and drainage facility, is required to ensure compliance with the geotechnical
recommendations. Inspection reports shall be submitted to the assigned Land Use Inspector
during the construction phases of those facilities. A final construction report shall be
submitted verifying compliance with the geotechnical recommendations.
6. The proposed subdivision shall comply with the 1993 King County Road Standards (KCRS)
including the following requirements:
a. Road A shall be improved at a minimum to the urban subaccess street standard. A
temporary turnaround shall be provided at the south end of Road A. This improvement shall
be designed in general conformance with the Preliminary Grading and Storm Drainage Plan
received April 19, 2006, unless otherwise approved by DDES. It is intended that this
improvement will match the proposed road improvements for the plat of Fleuve des Voiles
File L04P0002.
b. FRONTAGE and OFFSITE: The frontage and offsite portion of SE 1881" Street from the west
property boundary west to the existing road pavement shall be improved at a minimum to the
urban half -street standard. This improvement shall be designed in general conformance with
the Preliminary Grading and Storm Drainage Plan received April 19, 2006. Other designs for
this frontage and offsite improvement may be considered, as approved by DDES.
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c. Offsite Walkway Improvements: These walkway improvements shall be designed in general
conformance with the conceptual school walkway plan submitted April 19, 2006, unless
otherwise approved by DDES as providing sufficient safe walking conditions for resident
schoolchildren to their pertinent bus stops/schools. These improvements shall include any
necessary grading and storm drainage work necessary to either tight -line the abutting
roadside ditches or relocate the ditches within existing right-of-way.
• SE 1881h Street (120'h Avenue SE to match into the above 1/2-street improvement near
the west plat boundary) shall be widened to provide an eight (8) foot wide paved shoulder
along the south side of the street.
• SE 1881h St (1161h Ave SE to 1201h Ave SE) shall be widened to provide a minimum 16
foot wide paved surface as measured from the construction centerline. This will provide
an 11-foot wide travel lane and a 5-foot wide paved shoulder.
• 1201h Ave SE (SE 1881h St to SE 1841h St.) shall be widened to provide a minimum 16 foot
wide paved surface as measured from the construction centerline. This will provide an
11-foot wide travel lane and a 5-foot wide paved shoulder.
d. Modifications to the above road conditions may be considered according to the variance
provisions in Section 1.08 of the KCRS.
7. All utilities within proposed rights -of -way must be included within a franchise approved by the King
County Council prior to final plat recording.
8. The applicant or subsequent owner shall comply with King County Code 14.75, Mitigation
Payment System (MPS), by paying the required MPS fee and administration fee as determined by
the applicable fee ordnance. The applicant has the option to either: (1) pay the MPS fee at the
final plat recording, or (2) pay the MPS fee at the time of building permit issuance. If the first
option is chosen, the fee paid shall be the fee in effect at the time of plat application and a note
shall be placed on the face of the plat that reads, "All fees required by King County Code 14.75,
Mitigation Payment System (MPS), have been paid." If the second option is chosen, the fee paid
shall be the amount in effect as of the date of building permit application.
9. The proposed subdivision shall comply with the Sensitive Areas Code as outlined in K.C.C.
21A.24. Permanent survey marking and signs as specified in K.C.C. 21A.24.160 shall also be
addressed prior to final plat approval. Temporary marking of sensitive areas and their buffers
(e.g., with bright orange construction fencing) shall be placed on the site and shall remain in place
until all construction activities are completed.
10. Preliminary plat review has identified the following specific requirements which apply to this
project. All other applicable requirements from K.C.C. 21A.24 shall also be addressed by the
applicant.
A. Wetlands
The Class 1 wetland shall have a minimum buffer of 100 feet, measured from the wetland edge.
The wetland and its respective buffers shall be placed in a Sensitive Area Tract (SAT). A
minimum building setback line of 15 feet shall be required from the edge of the tract.
B. Streams
The Class 2 stream used by salmonids shall have a minimum 100-foot buffer, measured from the
ordinary high water mark (OHWM). The stream(s) and their respective buffers shall be placed in
a Sensitive Area Tract (SAT). A minimum building setback line of 15 feet shall be required from
the edge of the tract.
C. Alterations to Streams or Wetlands
If alterations of streams and/or wetlands are approved in conformance with K.C.C. 21A.24, then a
detailed plan to mitigate for impacts from those alterations will be required to be reviewed and
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Wehrman Plat
approved along with the plat engineering plans. A performance bond or other financial guarantee
will be required at the time of plan approval to guarantee that the mitigation measures are
installed according to the plan. Once the mitigation work is compieted to a DDES Senior
Ecologist's satisfaction, the performance bond may be replaced by a maintenance bond for the
remainder of the five-year monitoring period to guarantee the success of the mitigation. The
applicant shall be responsible for the installation, maintenance and monitoring of any approved
mitigation. The mitigation plan must be implemented prior to final inspection of the plat.
D. Geotechnical
The applicant shall delineate all on -site erosion hazard areas on the final engineering plans
(erosion hazard areas are defined in K.C.C. 21A.06.415). The delineation of such areas shall be
approved by a DDES geologist. The requirements found in K.C.C. 21A.24.220 concerning
erosion hazard areas shall be met, including seasonal restrictions on clearing and grading
activities.
11. The following note shall be shown on the final engineering plan and recorded plat:
RESTRICTIONS FOR SENSITIVE AREA TRACTS AND SENSITIVE
AREAS AND BUFFERS
Dedication of a sensitive area tract/sensitive area and buffer conveys to the public a
beneficial interest in the land within the tract/sensitive area and buffer. This interest
includes the preservation of native vegetation for all purposes that benefit the public
health, safety and welfare, including control of surface water and erosion,
maintenance of slope stability, and protection of plant and animal habitat. The
sensitive area tract/sensitive area and buffer imposes upon all present and future
owners and occupiers of the land subject to the tract/sensitive area and buffer the
obligation, enforceable on behalf of the public by King County, to leave undisturbed all
trees and other vegetation within the tract/sensitive area and buffer. The vegetation
within the tract/sensitive area and buffer may not be cut, pruned, covered by fill,
removed or damaged without approval in writing from the King County Department of
Development and Environmental Services or its successor agency, unless otherwise
provided by law.
The common boundary between the tract/sensitive area and buffer and the area of
development activity must be marked or otherwise flagged to the satisfaction of King
County prior to any clearing, grading, building construction or other development
activity on a lot subject to the sensitive area tract/sensitive area and buffer. The
required marking or flagging shall remain in place until all development proposal
activities in the vicinity of the sensitive area are completed.
No building foundations are allowed beyond the required 15-foot building setback line,
unless otherwise provided by law.
12. Suitable recreation space shall be provided consistent with the requirements of K.C.C.
21A.14.180 and K.C.C. 21A. 14.190 (i.e., sport court[s], children's play equipment, picnic table[s],
benches, etc.).
a. A detailed recreation space plan (i.e., location, area calculations, dimensions, landscape
specs, equipment specs, etc.) shall be submitted for review and approval by DDES and King
County Parks prior to or concurrent with the submittal of engineering plans.
b. A performance bond for recreation space improvements shall be posted prior to recording of
the plat.
13. A homeowners' association or other workable organization shall be established to the satisfaction
of DDES which provides for the ownership and continued maintenance of the recreation, open
space and/or sensitive area tract(s).
14. Street trees shall be provided as follows (per KCRS 5.03 and K.C.C. 21 A.16.050):
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a. Trees shall be planted at a rate of one tree for every 40 feet of frontage along all roads.
Spacing may be modified to accommodate sight distance requirements for driveways and
intersections.
b. Trees shall be located within the street right-of-way and planted in accordance with Drawing
No. 5-009 of the 1993 King County Road Standards, unless King County Department of
Transportation determines that trees should not be located in the street right-of-way.
c. If King County determines that the required street trees should not be located within the right-
of-way, they shall be located no more than 20 feet from the street right-of-way line.
d. The trees shall be owned and maintained by the abutting lot owners or the homeowners
association or other workable organization unless the county has adopted a maintenance
program. Ownership and maintenance shall be noted on the face of the final recorded plat.
e. The species of trees shall be approved by DDES if located within the right-of-way, and shall
not include poplar, cottonwood, soft maples, gum, any fruit -bearing trees, or any other tree or
shrub whose roots are likely to obstruct sanitary or storm sewers, or that is not compatible
with overhead utility lines.
f. The applicant shall submit a street tree plan and bond quantity sheet for review and approval
by DDES prior to engineering plan approval.
g. The applicant shall contact Metro Service Planning at �206) 684-1622 to determine if SE 188`h
Street in the subject area is on a bus route. If SE 188' Street in the subject area is on a bus
route, the street tree plan shall also be reviewed by Metro.
h. The street trees must be installed and inspected, or a performance bond posted, prior to
recording of the plat. If a performance bond is posted, the street trees must be installed and
inspected within one year of recording of the plat. At the time of inspection, if the trees are
found to be installed per the approved plan, a maintenance bond must be submitted or the
performance bond replaced with a maintenance bond, and held for one year. After one year,
the maintenance bond may be released after DDES has completed a second inspection and
determined that the trees have been kept healthy and thriving.
A landscape inspection fee shall also be submitted prior to plat recording. The inspection fee
is subject to change based on the current county fees.
15. To implement K.C.C. 21A.38.230 which applies to the site, a detailed tree retention plan shall be
submitted with the engineering plans for the subject plat. The tree retention plan (and engineering
plans) shall be consistent with the requirements of K.C.C. 21A.38.230. No clearing of the subject
property is permitted until the final tree retention plan is approved by LUSD. Flagging and
temporary fencing of trees to be retained shall be provided, consistent with K.C.C.
21A.38.230.B.4. The placement of impervious surfaces, fill material, excavation work, or the
storage of construction materials is prohibited within the fenced areas around preserved trees,
except for grading work permitted pursuant to K.C.C. 21A.38.230.B.4.d.(2),
16. A note shall be placed on the final plat indicating that the trees shown to be retained on the tree
retention plan shall be maintained by the future owners of the proposed lots, consistent with
K.C.C. 21A.38.230.B.6. (Note that the tree retention plan shall be included as part of the final
engineering plans for the subject plat.)
17. A note shall be placed on the final plat indicating that the trees shown to be retained on the tree
retention plan shall be maintained by the future owners of the proposed lots, consistent with
K.C.C. 21A.38.230.B.6. (Note that the tree retention plan shall be included as part of the final
engineering plans for the subject plat.)
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Wehrman Plat
The following summary describes how this new project will meet the "Core Requirements" and
the "Special Requirements" that apply:
Core Requirements
1. Discharge at the Natural Location: The site currently slopes, steeply in places, to the
east and the Soos Creek wetlands. There is a drainage ditch and culvert system flowing
east at the northern property boundary, along SE 188 Street. This drainage pathway
will be maintained. Otherwise, there are no well-defined drainage paths on the site, and
runoff occurs in a dispersed manner. The project proposes to detain all runoff from the
developed portions of the property and to disperse detained runoff to the Soos Creek
Wetlands.
2. Off --Site Analysis: A Level 1 offsite analysis was conducted for these plats as described
in Section 3.
3. Flow Control: Runoff from the site will be controlled to meet the Conservation Flow
Control requirements of the KCSWDM in a combination detention and treatment pond.
Discharges from the pond will be to a dispersion/energy dissipation facility. Appendix C
contains the KCRTS input and output.
4. Conveyance System: Pipe conveyance modeling is pending. See Section 5.
5.
Erosion and Sedimentation Control: Runoff from the grading and trenching
construction areas will be contained by temporary construction entrance(s), silt fencing
and a sediment pond in accordance with the KCSWDM during construction. The ESC
facilities will only be removed once all exposed site surfaces have been stabilized.
Other temporary erosion and sedimentation control measures will be installed as
needed. See Section 8.
• 6.
Maintenance and Operations: Until the City of Renton assumes responsibility for the
maintenance, the combination detention and treatment pond should be maintained as
described in Section 10 and Appendix D, which includes the KCSWM Maintenance
Requirements for Privately Maintained Drainage Facilities.
7.
Financial Guarantees and Liability: See Section 9. The bond quantities worksheet is
included in Appendix E.
8.
Water Quality: Treatment of runoff from the Pollution Generating Impervious Surfaces
(PGIS) will be provided in the dead storage portion of the combination detention and
treatment pond, which was sized according to the KCSWDM for Basic Water Quality
Treatment. Appendix C contains the calculations used to size the treatment facilities.
Special Requirements
1.
Other Adopted Area -Specific Requirements: Not Applicable.
2. Floodplain/Floodway Delineation: Not Applicable. The 100-year floodplain for the
adjacent Soos Creek wetlands does not extend onto the subject property.
3. Flood Protection Facilities: Not Applicable.
4, Source Controls: Not Applicable.
5. Oil Control: Not Applicable.
SECTION 3
OFF -SITE ANALYSIS
A Level 1 Offsite Drainage Analysis, by Barghausen Consulting Engineers, was submitted to
King County for this project as part of the approved Preliminary Plat submittal. Since then, the
downstream drainage path was verified, King County's IMAP database was again consulted,
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and the County's Drainage Complaints File was again solicited to make sure no subsequent
pertinent drainage complaints have been lodged in the interim. The Level 1 Off -Site Drainage
Analysis and Preliminary Detention Sizing Calculations report, dated December 2, 2004, and
revised November 9, 2005, by Barghausen Consulting Engineers, Inc. is available under
separate cover.
Task 1. Study Area Definition and Maps
The figures in Appendix B show the extent of the study area and the local topography. The first
figure shows that the project site constitutes less than 15 percent of the area tributary to the
point '/4 mile downstream from the site; therefore, a '/4 mile downstream analysis is deemed
sufficient. The Site Plan drawings show more detailed topographic information on the project
site.
Task 2. Resource Review
Agency mapping was reviewed and TEC contacted King County regarding documented
drainage complaints in the vicinity. The NRSC soils map identifies site soils in the proposed
development area as Alderwood Gravelly Sandy Loam, 0 — 6% slopes and 15 — 30% slopes.
Task 3. Field Inspection
In accordance with the KCSWDM, the existing site and off -site drainage systems were
inspected on June 15, 2004, and several times since.
Task 4. Drainage System Descriptions and Problem Descriptions
There are no pertinent reports of drainage problems in the immediate vicinity of the project.
The County's drainage complaints file was solicited again more recently, and the results of this
0 search are included in Appendix B. No additional pertinent drainage complaints have been
logged in the interim.
If the proposed drainage system fails, and the detention facility floods, the emergency overflow
path for runoff would be into the adjacent Soos Creek wetlands. These wetlands feed Soos
Creek, which flows south on the King County -owned property to the east of the project property.
Task 5. Mitigation of Existing or Potential Problems
To mitigate any water quantity impacts from the project, detention of runoff is proposed meeting
Conservation Flow Control requirements in accordance with the King County Surface Water
Design Manual (KCSWDM).
Water quality impacts will be addressed in a Basic Water Quality treatment facility; a
combination detention and treatment pond.
SECTION 4
FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
The following subsections describe the measurements and criteria used to size the detention
and treatment facility.
Existing Site Hydrology (Part A)
The drainage on the existing site was analyzed for this project with KCRTS. Figures provided
in the KCSWDM and KCRTS manual were used to determine project location and scale factor
parameters. The figure in Appendix C shows that the existing site is entirely forested and so
forested conditions were used in the KCRTS existing site modeling, which would be required for
Conservation Flow Control, regardless_ The site soils are classified Alderwood Gravelly Sandy
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Loam, either 0 - 6% or 15 — 30% slopes. Appendix C also contains the data and output from
the existing site hydrologic analysis.
Developed Site Hydrology (Part B)
The proposed drainage system will route runoff to a detention pond which will discharge to a
dispersion/energy dissipation facility draining to the adjacent Soos Creek wetlands. Appendix C
contains the data and output from the developed site hydrologic analysis.
The developed site conditions identified for this project and used in the KCRTS modeling are
summarized below.
Developed Site Conditions used for Hydrologic Modeling
areas in acres
Site Offsite
Bypass
Total
Impervious
3.729 0.500
0.00
4.229
Landscaping
1.517 0.000
0.198
1.715
Pasture
0.000 6.200
0.00
6.200
Subtotal
5.247 6.700
0.198
12.145
Performance Standards (Part C)
The Wehrman Plat project is subject to the requirements of the KCSWDM, for Conservation
Flow Control and must meet Historic Site Conditions Level 2 flow control standards.
Basic water quality treatment is required.
Conveyance features must be sized to convey the 25-year developed runoff and their
performance during the 100-year event should be checked to be sure that significant flooding
would not occur as a result.
Flow Control System (Part D)
The flow control is provided in a combination detention/treatment pond. The following table
summarizes the sizing requirements for the Level 2 detention pond.
Detention Pond Requirements
Required storage volume
68,625 cf
Effective storage depth
5.0 ft
Top area @ 1' freeboard
19,656 sf
Bottom area
9,900 sf
Orifice 41 diameter*
2.10" (2")
Orifice #2 diameter
3.20" (3-118°)
Orifice #2 height
3.00 ft
As shown on the plans, the pond will provide 69,882 cubic feet of detention storage,
Descriptions of the procedures used and calculations and computer output are included in
Appendix C.
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Water Quality (Part E)
Runoff from the site will be treated in the dead storage portion of the combination detention and
treatment facility, which was sized for Basic Water Quality Control. The following table
summarizes the sizing requirements for the treatment pond.
Treatment Facilities
Site Pond
Required wetpool volume (Vn)
17,899 cf
Wetpool depth (cell 1 & cell 2)
4 ft & 2 ft
Top area
6,608 sf
Cell #1 volume (25% - 35%)
4,643 cf — 6,501 cf
As shown on the plans, the pond will provide 25,588 cubic feet of treatment volume.
Descriptions of the procedures used and calculations and computer output are included in
Appendix C.
SECTION 5
CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Pending. The County's backwater routine (KCBW) will be used to size conveyance piping. The
proposed 12-inch diameter pipe system should convey the predicted 100-year peak flows
without flooding.
SECTION 6
SPECIAL REPORTS AND STUDIES
4DSeveral studies and reports were conducted and produced for this project and are available
under separate cover as listed below.
1. Level 1 Off -site Drainage Analysis and Preliminary Detention Sizing Calculations
prepared by Barghausen Consulting Engineers, Inc., dated December 2, 2004 and
revised November 9, 2005.
2. Traffic Impact Analysis prepared by Heath & Associates, dated November 2005.
3. Geotech Engineering Study tudy prepared by Earth Consultants, Inc., dated December 22,
2005,
4, Wetland Delineation Report prepared by Barghausen Consulting Engineers, Inc., dated
December 10, 2004.
SECTION 7
OTHER PERMITS
No other permits beyond those required by the City of Renton are anticipated to be required for
this project.
SECTION 8
ESC ANALYSIS AND DESIGN
The project proposes to utilize the permanent pond location for temporary sediment retention.
The permanent pond area is 19,656 square feet, which much larger than the 3,994 square feet
required for the erosion control pond. The sizing calculations for the various elements included
in the erosion control facilities are included in Appendix C.
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SECTION 9
is BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
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Bond Quantities: The County's standard Bond Quantities Worksheet is pending.
Facility Summaries: The County's Facilities Summary Sheet is included in Appendix F.
Declaration of Covenant: Not applicable. All the drainage facilities are located in public rights -
of -way, or dedicated drainage tracts, and will be maintained by the City two years after final
construction approval.
SECTION 10
OPERATIONS AND MAINTENANCE MANUAL
The detention/treatment pond and all drainage and street work within public tracts and rights -of -
ways will become the property of and will be maintained by the City of Renton two years after
final construction approval. Until such time, the drainage facilities should be maintained as
described in Appendix D (part of which was excerpted from the KCSWM Maintenance
Requirements for Privately Maintained Drainage Facilities).
10 TEC
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APPENDIX A
FIGURES
1. Technical Information Report (TIR) Worksheets
2. Site Location Map
3. Drainage Basins, Subbasins, & Site Characteristics
4. NRCS Soils Map
I�
`V, C
•
.7
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Project Owner'
Phone -
Address 5// 5-- _
,very F Gf%r4 ��'2D3
Project Engineerr��,-z�,�a�p
Company 22Z //1 C •
Phone �f2.1"-
0 Landuse Services
u ivisan / Short Subd. / UPD
❑ Building Services
M/F / Commerical / SFR
❑ Clearing and Grading
❑ Right -of -Way Use
❑ Other
Project Name lil�°lrrinatrl �r ____
DDES Permit##
Location Township
Range S
Section 3
Site Address /22AW
❑
DFW HPA
❑
COE 404
❑
DOE Dam Safety
❑
FEMA Floodplain
❑
COE Wetlands
❑
Other
❑ Shoreline
Management
Structural
RockeryNault
❑ ESA Section 7
4E
Technical Information Report
Site improvement Plan (Engr. Plans)
Type of Drainage Review paurilge/ Targeted/
Type (circle one): ulI / Modified /
(circle): Site
Small Site
Date (include revision
Date (include revision
dates):
dates):
Date of Final:
Date of Final:
Type (circle one); Standard / Complex / Preapplication / Experimental / Blanket
Description: (include conditions in TIR Section 2)
Date of
2009 Surface Water Design Manual
I
1/9'2009
2110
•
•
KING COUNTY, WAS14INGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Community Plan : leee, IV n
Special District Overlays:
Drainage Basin: SQgS 6-C-e �< _
Stormwater Requirements:
UU River/Stream ��D�C C*-,e GAS
❑ Lake
Wetlands
❑ Closed Depression
❑ Floodpiain
❑ Other
Soil Type
44/
❑ High Groundwater Table (within 5 feet)
❑ Other
❑ Steep Slope
❑ Erosion Hazard
❑ Landslide Hazard
❑ coal Mine Hazard
❑ Seismic Hazard
❑ Habitat Protection
Li
Slopes
e�
❑ Sole Source Aquifer
❑ Seeps/Springs
Additional Sheets Attached AgCS f 1,;Lj 1F-5 �Z)
2009 Surface Water Design Manual
2
Erosion Potential
1/9/2009
-�lv
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
0 TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
•
•
REFERENCE
Rf Gore 2 — Offsite Anal
Sensitive/Critical Areas
SEPA
❑ Other
LIMITATION / SITE CONSTRAINT
R[Additional Sheets Attached I
Park 3 . TtR'.. UMfy14f Y FI T :`:
ro.U:de,00 T4 -simn $hest, ei.t reshcld.
Threshold Discharge Area:
name or description)
Core Requirements (all 8 apply)
Discharge at Natural Location
Number of Natural Discharge Locations:
OfFsite Analysis
Level: 2 / 3 dated:
Flow Control
Level: 1 / 2 / 3 or Exemption Number
Incl. facility summary sheet
Small Site BMPs
Conveyance System
Spill containment located at:
Erosion and Sediment Control
ESC Site Supervisor
Contact Phone:
After Flours Phone:
Maintenance and Operation
Responsibility: Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and
Provided: es No
Liability
Water Quality
Type: asic / Sens. Lake ! Enhanced Basicm ! Bog
(include facility summary sheet)
or Exemption No.
Landscape Management Plan: Yes / No
Special Requirements as applicable)
Area Specific Drainage
Type: CDA / SDO / MDP / BPI LMP / Shared Fac. ! None
Requirements
Name:
Floodplain/Fioodway Delineation
Type: Major / Minor / Exemption / None
100-year Base Flood Elevation (or range):
Datum:
Flood Protection Facilities
Describe:
Source Control
Describe landuse:
(comm./industrial landuse)
Describe any structural controls:
2009 Surface Water Design Manual 3 I/9/2009
411 o
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
• TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
•
Oil Control High -use Site: Yes / No
Treatment BMP:
Maintenance Agreement: Yes / No
Other Dr,
Describe:
dart 1*4�{�I€Yrl■T VASUER fwTS .i T 9i§Y 4PS E j£ i, tE
MINIMUM ESC REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
AFTER CONSTRUCTION
Clearing Limits
Stabilize Exposed Surfaces
Cover Measures
CTRemove and Restore Temporary ESC Facilities
Perimeter Protection
'Clean and Remove All Silt and Debris, Ensure
Area Stabilization
Operation of Permanent Facilities
r�,�
u Sediment Retention
uTraffic
r
Flag Limits of SAO and open space
Or Surface Water Collection
preservation areas
❑ Other
ErDewatering Control
Dust Control
Flow Control
P dif,.1:4..S.TORMVV 'E
omme >i rtl
Ffow Control
Type/ escrition
Water Quality
Type/Description
E Detention
❑ Infiltration
❑ Regional Facility
❑ Shared Facility
❑ Fiow Control
BMPs
❑ Other
/7 /
�"O1
❑ Biofiltration
Wetpool
❑ Media Filtration
❑ Oil Control
❑ Spill Control
❑ Flow Control BMPs
❑ Other
L M . r� / ��
2009 Surface Water Design Manual
1 /9/2009
•
•
•
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Drainage Easement
❑ Covenant
Native Growth Protection Covenant
Tract
❑ Other
❑ Cast in Place Vault
U"Retaining Wall
❑ Rockery > 4- High
❑ Structural on Steep Slope
❑ Other
I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were
incorporated into this worksheet and the attached Technical Information Report, To the best of my
knowledge the information vided here is accurate.
/1-23 -
2009 Surface Water Design Manual
E
1/9'2009
F/ t o
•
0
a
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t
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1
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v
F
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pg�
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a
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ng
Renton
e
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C UL VOC—T S Yf,7Z:�-M
rainy Basins, ubbas ns & Site Char. - F
�p h
V
law,
CIVrD slz::-
-
•PFA - • 7
2Lorr = -7-2` q<.
l ne Intormwion included on tN8 niap ira' 0n caniri ed by King Crunly staff fmw a variety ❑f sourrrs and is subject to-changew
Warranties,.exuress or implied., as to aMlracy, cnrnple'enesa, tianeiiness, cir rights to the use of such information. T#Iis-document is
shah not be liable for any goner 31 special indirect, incidental, or eonscrtuentisl darriagos including; but not lfmited:tb lost revenue!
inierrna".ion cor;lained on ibis rn.ap: Any sale of this map or information on this map is prohibited except by written perinki fon of King(
Date. 9l2212U08 Source, 'K g ,n�:hly AIAP - S3tmsiUve 1 cas Qitlf3:1! new .metrokc govj,GESriMAP}
jt notice. King County.mnkes no.rep
intended for use as a survey pr(i[lui
Jost profits resulting from ihs ust b.
nty,
ij6l sf7E
P/bfvsED A%Yga . zart/
S�rdcc[TI�2E AIL42T
F2" Dok!
F�,*. 0
Soil Map —King Counhy Area, Washington
(Wehrman Plat)
V r�frters
p :i0 6U 120 180
f] ' 00 LU{] 400 60Q
Natural Resources Web Soil Survey 2.0 9/2212008
Conservation Suivice National Cooperative Sail Survey Page 1 of 3
0
0 0 0
MAP LEGEND
Area of Interest (AOI)
€
Area of Interest (AOI)
Solis
L
Soil Map Units
Special
Point Features
W
Blowout
N
Borrow Pit
,X.
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
,16
Marsh
R
Mine or Quarry
O
Miscellaneous Water
O
Perennial water
y
Rock Outcrop
f
Saline Spot
Sandy Spot
Severely Eroded Spot
(j
Sinkhole
3>
Slide or Slip
fir
Sodic Spot
Spoil Area
Q
Stony Spot
Soil Map —King County Area, Washington
(Wehrman Plat)
MAP INFORMATION
M
Very Stony Spot
Original soil survey map sheets were prepared at publication scale.
Viewing scale and printing scale, however, may vary from the
Wet Spot
original. Please rely on the bar scale on each map sheet for proper
Other
map measurements.
Special Llne Features
Source of Map: Natural Resources Conservation Service
r^'
Gully
Web Soil Survey URL: http://websolisurvey.nres.usda.gov
'
Coordinate System: UTM Zone 10N
Short Steep Slope
This product is generated from the USDA-NRCS certified data as of
Other
the version date(s) listed below.
Political Features
Soil Survey Area: King County Area, Washington
Pubile Land Survey
Survey Area Data: Version 4, Nov 21, 2006
0
Township and Range
Date(s) aerial images were photographed: 7/10/1990; 711811990
0
Section
The orthophoto or other base map on which the soil bales were
Municipalities
compiled and digitized probably differs from the background
a
Cities
imagery displayed on these maps. As a result, some minor shifting
Areas
of map unit boundaries may be evident.
®
Urban
Water Features
Oceans
,-
Streams and Canals
Transportation
Rails
Roads
,yr
Interstate Highways
r
US Routes
State Highways
Local Roads
Other Roads
ODA Natural Resources Web Soil Survey 2.0 9/2212003
Conservation Service National Cooperative Soil Survey Page 2 of 3
•
•
•
Soil Map —King County Area, Washington
Map Unit Legend
Wehrman Plat
ikiEF„�. Fi.g,CRit1t�
a Y
¢..„. F:iax <, .._��k.v:
Sit
Ag8 �Alderwood gravelly sandy loam,
13.9
67.2%
0 to 6 percent slopes
27.4%
AgD
Alderwood gravelly sandy loam,
- -- -- 5.7
15 to 30 percent slopes
'
No
Norma sandy loam
1.1
5,4%
Totals for Area of Interest (AO I)
U Natural Resources
Conservation Service
Web Soil Survey 2.0
National Cooperative Soil Survey
20.7
912212008
Page 3 of 3
•
APPENDIX B
OFF -SITE ANALYSIS
DRAINAGE SYSTEM TABLE AND MAP
•
0 0 0
OFF -SITE ANALYSIS DRAINAGE SYSTEM TABLE
SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #Z
Basin: Soos Creek Subbasin Name: Subbasin Number:
a ,.' �R a
{E3jF� .•. �.
l�d�"'$�
a
'�a'ar�:'Isci,.�
@ i�or�$-�f i.1iE1
rI]�'iF�i
��((.,ee�
^f - - >3[
�A '
,!✓5 Q.eAt..S
x
,�.
,[�
€itt i'
t � r
't a....:1:"d �,, ..5..."C`._y
-
',
('<
resid
e�f
,� ... s
s s
is.....
?'�T€¢:w
Vic't27�n
#�bttt fe, ,`.�f�eEihood ofpro
_.,.< .
.k< ��
F
�, �E�Sie_
.Fq� t.:z�
Ci
9m�JUt'r'il
-,eC:: ,�.x
firer �l
J
�..
3 €�,F ` ..-
,}^,
� "`P�M°....'P i.
*�3E�i.�. S^.'1:81� �IK, `•.`.Y.^�4[SM!f��i„R�jv
p{�{ 1��aJj�Rl��[y
e4 fT
_ ..
E'1 P
A -- B
Sheet flow and sub
Soos Creek grassy
2% -
0' — 230'
None noted
Wet marshy area
surface flow
wetland area
3%
B --- C
Wetland/stream/
Soos Creek grassy
1 % -
230' — 790'
None noted
Wet marshy area, relatively
channel flow,
wetland area
2%
inaccessible
a rox. 150' wide
C D
48" culvert
Crossing 192nd
790' 890'
None noted
This culvert was not visible
at the time of the inspection,
but according to the
previous downstream
analysis, has conveyed 100-
year flows without flooding.
D - E
Stream
Soos Creek
0.5% -
890' —
None noted
Creek flows in a wide
1%
1,320 +
wetland area.
98-4VnB04
17("
A
•
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az ���rL€ 9R°s
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iff
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it � � � E �,, � • �eS ��hi: # ,# ._5 "tit `.
1 E
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•
•
SECTION 3.2 RUNOFF COMPUTATION AND ANALYSIS METHODS
KCRTS is the "Effective Impervious Area" (EIA), the total impervious area multiplied by the effective
impervious fraction. See Table 3,2,21, p. 3-29 for effective impervious fractions that apply to standard
impervious surfaces. Table 1.2.3.0 lists effective impervious factions for alternative materials and
approaches.
Non -effective impervious area (i.e., total impervious area less EIA) is assumed to have the same
hydrologic response as the immediately surrounding pervious area. For example, for existing
residential areas with rooftops draining to splash pads on lawns or landscaping, the non -effective portion
of the roof areas would be treated as pasture for predevelopment conditions (if DU/GA < 4.0) and grass
for post -development conditions. Note: Credits for infiltration/dispersion of downspouts on individual
lots in proposed single family residential subdivisions are applied separately on a site -specific basis (see
Note 3, Table 3.2.2.E).
The effective impervious fraction can be selected from Table 3.2.2.E or determined from detailed site
surveys. With the exception of figures for compacted gravel and dirt roads and parking lots, the figures in
Table 3.2.2.E are average figures cited by the USGS (Dinicola, 1990).
MIME
OSHA
% Impervious(1)
Dwelling Units/Gross
% Impervious
Dwelling Units/Gross
Acre
Acre
1.0 DUIGA
15(2)
4.5 DU/GA
46
1.5 DU/GA
20
5.0 DU/GA
48
2.0 DU/GA
25
5.5 DU/GA
50
2.5 DU/GA
30
6.0 DU/GA
52
3.0 DU/GA
34
6.5 DU/GA
54
3.5 DU/GA
38
7.0 DU/GA
56
4.0 DU/GA
42
7.5 DU/GA
58
For PUDs, condominiums, apartments, commercial businesses, and
industrial areas, percent impervious coverage must be computed.
Notes:
(1) Includes streets and sidewalks.
(2) These figures should be adjusted by the effective impervious fraction given in Table
3.2.2.E, if
applicable. Values from Table 3.2.2,E may be interpolated as necessary.
I/9/2009 2009 Surface Water Design Manual
3-28
WX
3.2.2 KCRTS/RUNOFF FILES METHOD — GENERATING TIME SERIES
W,
i
;f. �..... �.' i; K i?! F1 1-'WiM G y�. ] s.4Y y
.E � fix' ki ��
s#,PSaasli'1%ga
il
1•'�, i" _. h f hH
rg$qp'
YTEA✓ � TI Mxh € EP T -_ k L,j} � S`�. +�4 !u � n.�'�ayPYf4� i3ppiF O �Y "� @ fll� �p iLErii�. ��ii_ . EBB.. �
•4F.} Y. � �W
Land Use
Predevelopment
Post -Development
Commercial, Industrial, or Roads with Collection System
0,95
1.00
Multi -Family or High Density Single Family"' (74 DU/GA)
0.80
1.00(3)
Medium Density Single Familyp' (4 DU/GA)
0.66
1.00")
Low Density Single Familyl2} (1 DUIGA)
0.50
00{31
Rural{21 (c 1 DU/GA)
0.40
1.00(3)
Gravel/Dirt Roads and Parking Lots, Roads without
0.50
0.50
Collection System
Notes:
(1) The effective impervious fraction is the fraction of actual total impervious area connected to the
drainage system. These figures should be used in the absence of detailed surveys or physical
inspection (e.g., via pipe, channel, or short sheet flowpath).
I21 Figures for residential areas include roadways.
(3) Section 5.2 outlines where the use of Flow Control BMPs may be used to reduce the effective
impervious area of the project
Example
Determining the KCRTS land use data for an existing 20-acre residential area, with an average lot
size of 9600 square feet (4.5 DU/GA), surrounding a 5-acre forested open space tract would entail the
following calculations;
From Table 3.2.2.D, the portion of basin assumed impervious at 4.5 DU/GA
Total Impervious = 0.46 x 20 acres = 9.2 acres D -IT(
Existing Pervious (grass) = 20 acres - 9.2 acres = 10.8 acres (p ,
Existing Pervious (forest) = 5 acres
From Table 3.2.2,E, the effective impervious area
Effective Impervious Fraction = 0.8 (at 4.5 DU/GA) '0,5
Effective Impervious Area = 0.8 x 9.2 acres = 7.36_ acres -,>, 5 ( I - a _ 0, a _
Non -Effective Impervious. Area = 9.2 acres - 7.36 acres = 1.84 acres 0,
Add the non -effective impervious area to the area of the surrounding pervious land cover.
Total Grass Area = 10.8 acres + 1.84 acres = 12.64 acresv =Y �-! ���-�i� • �L,
Total Forest Area = 5 acres
Effective Impervious Area = 7.36 acres
These are the acreages that would be input into the KCRTS model when creating the time series.
2009 Surface Water Design Manual 1/9/2009
3-29
•
APPENDIX B-1
DRAINAGE COMPLAINT ANALYSIS
•
r5-
•
f
WEHRMAN PROPERTY
w
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KinolovWftw and Land ReSwAvism - Ift sw-111M: Se M
2w Printed: 06103/2008 12:51:41 PM
IbMw Type Type of ProW n Addr= of Pr@WM Cmnalts
1977-0072
197MO80
1978-0081
1982-0539
1984-0313
1984-0314
1987-1049
1988-0238
1988-0238
1989-0003
1989-0192
1996-1550
1997-1179
1997-1179
1997-1179
1997-1301
1998-0926
2000-0398
2003-0545
2003-0762
2003-0909
2004-0952
2005-0244
2005-0316
2005-0446
2008-0253
2008-0254
C
C
C
C
R
C
C
C
ER
C
G
C
C
NDA
R
C
C
C
WQR
W QA
WQC
C
C
C
WQA
R
R
FLDG
12202
SE 192ND ST
PONDING
19248
121ST PL SE
DRNG
19248
121ST PL SE
FLDG
12600
SE 192ND ST
FLDG
13250
SE 192ND ST
FLDG
13250
SE 192ND ST
FLDG
18431
120TH AVE
PIPE
18431
120TH AVE
DRNG
18612
120TH AVE
DRNG
18612
120TH AVE
DRNG
19121
124TH AVE
DRAINAGE
19113
121ST PL
DRAINAGE
19113
121 ST PL
DRAINAGE
19113
121 ST PL
DRAINAGE
19125
121STPL
DRAINAGE
19133
121 ST PL
DDM
12625
SE
192ND ST
WQB
18601
126TH PL SE
WQAI
19433
VASHON HWY SW
WQDR
18601
126TH PL SE
DTA
12701
SE
191 ST PL
DDM
18617
126TH PL
DTA
12503
SE
188TH PL
WQAI
12600
SE
192ND ST
DDM
19248
121STPL
DDM
19210
121 ST PL
SE
SE
SE
SE
SE
SE
SE
SE
SE
SE
SE
SE
SE
EAST OF BENSON HWY
EAST KENT AREA
TO ROADS DIVA
SE 192ND ST1134TH AVE SE
TO RD COORD 04127187.
NEW DRIVEWAY WILL IT FLOOD
NEED EXTENSION OF 42" CULVERT
INCREASED RUNOFFICHANNEL
X PIPE NOT WORKING
PLUGGED D1W CULVERT IMPACT TO
INSTALLATION OF DRNG IN RMf
INSTALLATION OF DRNG IN RIW
INSTALLATION OF DRNG IN RIW..
SUBSTANDARD INSTL OF DRNG SYS PVT
APPARENT OBSTRUCTION IN ROAD
REQUEST TO DIVERT FLOW
PROBLEM CORRECTED RP MOVED
BMPS are ALL IN PLACE
AUTO FLUID RESIDUE ON STREET AS A
Referral from KC Roads. Flooding of
Wet backyard caused by broken storm line?
Backup in KC Rd conveyance system.
BMPS IMPLEMENTED AS PART OF KENT
ORPHAN FACILITY REVIEW FOR THE
Page 1 of 1
•
Tbras Page
686F2 Sj j' Z20 ? s� f,rrd
6$6F2
. 686F2 DreS+
686F2r
686F21
68fiF2
686F2r 7
686 F2 it R
686F2 ITT
686 F
686F2� _
686F2 15kdtiV— Qr, ��D 54E IgMoA 5 `.
686F2' r 6861`2
686F2
686F2 {
686F2
686F2
686F2(,
686F2 686F2 � � D 0 four ekd+
686 F2
686F2
686F2: j
686F2 — D +$
686F2 — - pp vje1+
•
•
PCSk-W Fu Note
7671
Date 91 ` ��
Ra9ea�
co.�oL
�• llcl�
Gr�JN1�,
ifi�aCay dater aq� LBIId RB8ei�"c� - �raine�e 8er
CUM
Prated : W1412W 1-37!24 PM
C"iWilt
Typo
1Xpi
of Pm*m
I of PI'Oi lw
Como"
Ift pal
Km�r
t�N
19764110
C
DRNG
13038
SE 188TH PL
BLVD LN
886G2
1077.0072
C
FLDG
12202
BE 192ND ST
686F2
1977-0074
C
FLOG
13210
SE 192ND ST
FILLIDRAIN WAY
686G2
1976.0080
C
PONDING
19248
121ST PL SE
EAST OF BENSON HWY
888F2
1978-0081
C
DRNG
19248
121ST PL SE
68BF2
1981-0225
C
FLDG
13210
$E 192ND ST
DRAIN WAY FILLED
686G2
1982-0539
C
FLDG
12600
$E 192ND ST
EAST KENT AREA
66OF2
19134-0313
R
FLDG
13250
SE 192N0ST
TO ROADS DIVA
686F2
19WO314
C
FLDG
1$250
BE 192ND Si
SE 192ND ST/134TH AVE 5E
686F2
198"534
X
DRNG
13250
SE
102ND ST
LTR TO COMPLAINT
686G2
1980,0617
C
DRNG
13432
SE
167TH ST
FLDG ON SIDEWALK
886G2
198B.0818
C
FLDG
13440
SE
182ND ST
RFP:85-0832 NESPER 87.0770
686G2
198MM6
ER
FLDG
13M
BE
192ND ST
(REF;W$32 NESPER) PVT PROD.
686G2
1966.7278
CL
CLAIM #10373
688G2
1987-077D
` C
FLDG
13440
SE
192ND ST
FAIRWOOD SEE 86-0810
60602
1987-1049
C
TO RD COORD 04/27187,
686F2
1986.0118
x
DRNG
1325C
5E
192ND ST
SEE 85.1278 NESPERIGL • FORSESTTRAf
66SU
1985-0238
C
FLDG
i8431
1207H AVE
SE NEW DRIVEWAY WILL IT FLOOD
688F2
1988-0238
ER
PIPE
18431
120TH AVE
SE NEED EXTENSION OF 42" CULVERT
686F2
1968-0305
C
BLOCKAGE
12716
SE
188TH PL
EASEMENT-FAIRWOOD/WALL CONSTRUC
886132
198MD03
C
DRNG
18812
120TH AVE
SE INCREASED RUNOFFICHANNEL
686F2
1989-0192
C
DRNG
16612
120TH AVE
BE X PIPE NOT WORKING
686FZ
1989-0550
C
EROSION
19118
130TH AVE
SE OLD EASEMENT CHANNEL MAINTENANCE
586G2
19WO665
C
DRNG
13300
BE
184TH PL
WATER IN BASEMENT/YARD DRAIN CLOG
68602
1900.0056
C
FLDG
12700
SE
107TH PL
UTILITY EA$EMT CLOGGED 90.0259
686G2
1993.0250
C
'FLDG
12700
BE
187TH PL
PV'r DITCH OVERFLOW
686G2
1990.1106
C
DRNG
13517
BE
189TH PL
CULVERT SLEW TRASH RACK/ CEDAR ES
68GG2
1990.1106
NDA
DRNG
13517
SE
169TH PL
CULVERT BLEW TRASH RACK CEDAR ES
688G2
1990-1166
C
DRNG
111421
SE
189TH PLACE
13517 $S 169TH PL
698G2
1990-1155
NDA
DRNG
13421
$E
189TH PLACE
REF 90-1106
686G2
1990.1158
C
DRNG
13429
BE
189TH PLACE
13517 SE 169TH PL
686G2
1990-1156
NDA
DRNG
13429
BE
189TH PLACE
REF 90-1106
680GZ
1990.1157
C
DRNG
13436
SE
189TH PLACE
13517 BE 189TH PL
688G2
19-40 1157
NDA
DRNIG
13435
SE
189TH PLACE
REF 90-1106
688G2
1990.115E
C
DRNG
18917
5E
189TH PLACE
13$17 SE 189TH PL
688G2
1990.1158
NDA
DRNG
10917
BE
189TH PLACE
REF 90-1106
688G2
19ON1159
C
DRNG
13523
SE
18STH PLACE
13517 SE 189TH PL
68502
Page 1 013
7�
�
TY1a of f�t'Dp M
�I'n8 of Ptdl w
Colulit�
im po
lumir
1990-1159
NDA
DRNG
13523
SE
189TH PLACE
REF 90.1106
686G2
1990-1160
C
DRNG
13529
BE
189TH PLACE
13517 SE 189TH PL
ma=
1990.1160
NDA
DRNG
13529
BE
169TH PLACE
REF 90-1 106
6B832
1990-1630
C
FLDG
19114
130TH AVE
BE
STREAM OVERFLOW
888G2
1991.1090
C
DRAINAGE
18532
131ST AVE
SE
WATER PONDS IN YARD
686G2
1991-1000
NDA
DRAINAGE
18532
131ST AVE
BE
YARD PONDS
886G2
1991-1090
SR
DRAINAGE
1802
131ST AVE
SE
TO CIP
68502
1903-0041
WQC
SEDIMENT
13120
SE
192ND ST
$$6G2
1994-0676
WQC
GRE:ENH2O
SE
192ND & 134TH A
SE
DUCK WEED
B85G2
1995-01"
WQC
OIUCARS
19312
133RD AVE
SE
RESIDENTIAL CAR MAINTENANCE
1588G2
1995-0374
C
FILLING
SE
192ND & 134TH
SE
WETLAND - REFD TO DOES
06G2
199&0391
FUR
POND?
19118
130TH PL
5E
HOLD-GPR WILL CALL HER 4 MORE DETAI
$86G2
199$,0301
NDA
POND?
19118
130TH PL
SE
HOLD-GPR WILL CALL HER 4 MORE DETAI
66$G2
1996oD391
R
POND?
19118
130TH PL
SE
HOLD-GPR WILL CALL HER 4 MORE DETAI
555G2
1990.0480
C
CRK FLDS
13607
SE
192ND
7 GROUNDWATER IMPACT WATER PONDI
666G2
1906.0921
FCR
R(D POND
13341
9E
195TH ST
OUTLET PIPE 09STRUCTE E) A,95FSSMEN
686G2
1998-1428
C
SWALE
1891E
129TH PLACE
SE
OFFSITE FLOW IMPACTING PVT DRNG BY
686G2
1996-1428
NDA
SWALE
18914
129TH PLACE
SE
OFFSITE FLOW IMPACTING PVT DRNG 5Y
686G2
1996-1428
R
SWALE
18914
129TH PLACE
BE
OFFSITE FLOW IMPACTING PVT DRNG SY
686G2
-.} 199$-1550
C
DRNG
19121
124TH AVE
SE
PLUGGED DIW CULVER7 I MPACT TO PVT
886F24ir—
I8W1894
C
RUNOFF
13416
BE
167TH
WATER OVER SIDEWALK GROUNDWATE
68BG2
1997-0040
C
DRNG
13007
BE
1$8TH PL
GROUNDWATERISHEETFLOW PONDING
656G2
1997.1179
G
DRAINAGE
19113
121ST PL
5E
NSTALLATION OF DRNG IN RN OLD/OFF
88BF2
1997-1179
NDA
DRAINAGE
19113
121ST PL
BE
INSTALLATION OF DRNG IN RAV OLD/OFF
6WF2
1997.1179
R
DRAINAGE
10113
121ST PL
SE
INSTALI ATION OF DRNG IN RW OLDIOFF
686F2
1997-1301
C
DRAINAGE
19123
121ST PL
$E
SUBSTANDARD INSTL OF DRNG SYS PVT
6NF2
1997-1319
FOR
DUMPING
21709
146TH ST E
DUMPED BATTERY IN RID POND
B86Ga
1993-0026
C
DRAINAGE
19133
121ST PL
SE
APPARENT OBSTRUCTION IN ROAD DRN
W15F2
1999-0174
FCR
CLGINLEMT
13415
Sty
187TH PL
INLET PIPE APPARENTLY OBSTRUCTED
G86G2
1999#40
C
SPRINGS
13518
SE
186TH PL
NEW SFR GROUND WATER INFIL ONTO P
686G2
199D 0632
C
EASEMENT
19114
130TH AVE
BE
INFO PROVIDED ABOUT RID POND ON PR
686G2
1999-0679
FOR
FENCE
18932
133RD PL
gE
I,EANIN6 FENCE; N@IDS REPAIR
666G2
20OM398
C
DDM
1262S
BE
102ND ST
REQUEST TO DIVERT FLOW DISCHARGIN
686F2
2000-0735
FCR
MNM
19000
134TH AVE
SE
CEDAR BOARD FENCE ARC}UND PERIMET
686G2
2001.050
W(0P
WQP
13120
SE
192ND ST
68$G2
2032.0094
Fi
REM
13055
BE
%2ND ST
SWM#63 REME;ASURE OF ORIGINAL 17.7
6r16G2
2002.0094
FIR
REM
13055
SE
192ND ST
SWM483 REMEASURE OF ORIGINAL 17,7
6MG2
2002-0204
FCR
MMG
19000
134TH AVE SE
1) PSE UTILITY BOX DAMAGED, CALLED
686G2
2002.0424
C
DDM
13003
BE
186TH PL
SINKHOLE DEVELOPED APPARENTLY OV
68OG2
2002.0424
NDA-
DDM
13003
SE
188TH PL
SINKHOLE DEVELOPED APPARENTLY QV
68602
Page 2V$
0
- 5
000
Ty"
f Yp of "ft
A&M Of Pe06 mcwe
6g1�1�t8
1a'Qi �8
Fair
2002.0424
R
DOM
13003
SE 188TH PL
' V APPARENT
S NKH4LE DEVELOPED APPARENTLY 4V
6 6602
2003-0266
C
DDIV
18759
130TH AVE SE
LOCAL PONDING PROBLEM. MAY BE THE
696G2
2003.0545
WQR
WQB
18801
12aTH PL SE
BSSF2
2003.0762
WQA
WQAI
19433
VASHON HWY SW
BMPS ary ALL IN PLACE
686F2
2003-0909
WQC
WQDR
18601
126TH PL SE
AUTO FLUID RESIDUE ON STREET A$ A R
6861`2
•
Svbsev, e0 ` G.a P � i rt �3
� � aYtt,
, , d✓ i,
Pe beGWer ad'eA
i1S�Y-t�C 1'�n UL
YDJr,-3i
�/l��
"fPvp_r,`
Page 3 of 3
•
APPENDIX C
ANALYSIS AND DESIGN
0
•
•
•
MEHRMAN PLAU
sffE COYERAGE AREAS
LIMITS
DISTUI
E
BYPASS
I
WETLANDS
lj
pETEt TI 'N
jr.
;POW
4
1
LIMITS OF
bISTURBANCE
+
: � 1
i
75 150
1
SCALE: 1" = 150 ft
EXISTING SITE (SF): PROPOSED SITE (SF): OFF --SITE TRIB. AREA (SO:
FOREST: 237,176 (5.445 AC) BUILDINGS: 103,971 (2.387 AC) IMPERVIOUS: 22,780 (0.500 AC)
PAVEMENT: 43,942 (1.009 AC) PASTURE: 270,072 (6.200 AC)
TOTAL: 237,176 (5.445 AC) SIDEWALK: 3,260 (0.075 AC)
POND: 11,280 (0,295 AC) TOTAL: 291,852 (6.700 AC)
IMP SUB —TOTAL: 162,453 (3.729 AC)
LANDSCAPE: 65,095 (1.517 AC)
TOTAL: 228,548 (5.247 AC)
BYPASS (SF):
LANDSCAPE: 8,628 (0.198 AC)
72
r �
•
Impervious Areas Summary for Detention and Treatment Sizing
Project: Wehrman Plat
Project #: 485-MW
Date: 2/28/2012
Existin
(s#j
ac
Proposed
s
ac
F
Buildings:
103,971
2,387
Pavement:
43,942
1.009
Sidewalk:
3,260
0.075
Forest:
237,176
5,445
Pond:
11,280
0.259
Subtotal:
237,176
5.445
Imp:
162,453
3.729
Landscape
66,095
1.517
Subtotal:
228,548
5.247
Landscape:
8,628
WNW
0.198
Imp:
21,780
0.500
Imp:
21,780
0.500
Pasture:
270.072
6.200
Pasture:
270.072
6.200
Subtotal:
291,852
6.700
Subtotal:
291.852
6.700
Tot, Imp.:
21,780
0.500
Tot. Imp.:
184,233
4.229
Tot. Pasture:
270,072
6.200
Tot. Grass:
66,095
1.517
Tot. Forest:
237,176
5.445
Tot. Pasture:
270,072
6.200
Total:
529,028
12,145
Bypass Grass:
8,628
0.198
Total:
529,028
12.145
Backcheck:
529,028
12,145
Backcheck:
529,028
12.145
Drainage Calcs MW.xlsx Imp Areas Summ.
2/28/2012
•
Wehrman Plat
Runoff Ca1cs
12/16/09
Flow Frequency Analysis
Time Series File:exist.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates ---
Flow Rate Rank Time of Peak
(CFS)
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
. Flow Frequency Analysis
Time Series File:dev.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates ---
Flow Rate Rank Time of Peak
(CFS)
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
sumpks.txt
LogPearson III Coefficients
Mean= -0.346 StdDev= C,202
Skew= 0,037
----Flow Frequency Analysis-------
- - Peaks - - Rank Return ?rob
(CFS) Period
1.35 100.00 0.990
1.18 50.00 0.980
1.02 25.00 0.960
0.820 10.00 D.900
0.779 8.00 0.875
0.667 5.04 0.800
0.450 2.00 0.500
0.317 1.30 0.231
LogPearson III Coefficients
Mean= 0.140 StdDev= 0.120
Skew= 0.391
-----Flow Frequency Analysis-------
- - Peaks -
- Rank Return
Prob
(CFS)
Period
2.85
lOO.00
0.99C
2.58
50.00
0.980
2,32
25.00
0,960
1.99
10.00
0.900
1.92
8.00
0,875
1.73
5.00
0.800
1.36
2,00
0.500
1,11
1.30
0.231
Flow Frequency Analysis LogPearson III Coefficients
Time Series File:bypass.tsf Mean= -1.791 StdDev= 0.213
Project Location:Sea-Tac Skew= C.249
---Annual Peak Flow Rates ---
Flow Rate Rank Time of Peak
(CFS)
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Computed Peaks
Level 2 Det Pond (V deep)
Int size = (1.18-(0,450*0.5)/36-1
= O.D27
1st int. = 0.450*0.5
= 0.225
Qmax (Orif 1) = 4/3*0.225-0.016
= 0.284
Ht (Orif 2) = 3/4*4
= 3'
-----Flow Frequency Analysis-------
- - Peaks -
- Rank Return
Prob
)CFS)
Period
0,055
100,00
0.990
D.047
5C.00
0.980
0.040
25.00
0.960
0.C31
10.00
0.9D0
0.029
8.00
0.875
0.024
5.OD
0.800
0.016
2,OD
0.500
0.011
1.30
0.231
Page 1
Wehrman Plat KCRTS runoff output file: pond.doc
KCRTS Command
-------------
CREATE a new Time Series
--------------------------
Production of Runoff Time Series
Project Location Sea-Tac
Computing Series exist.tsf
Regional Scale Factor 1.00
Data Type Historic
Creating Hourly Time Series File
Loading Time Series File:Co\KC_SWDM\KC_DATA\STTF60H.rnf
Till Forest 5.72 acres
Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rrif
Till Pasture 6.19 acres
Loading Time Series File!C:\KC_SWDM\KC
DATA\STE160H.rnf
Impervious 0.55 acres
--------------
Total Area 12.46 acres
Peak Discharge: 1.16 CFS at 6:00 on Jan 9 in 1990
Storing Time Series File:exist.tsf
Time Series Computed
KCRTS Command
-------------
CREATE a new Time Series
------------------------
Production of Runoff Time Series
Project Location : Sea-Tac
Computing Series dev.tsf
Regional Scale Factor 1.D0
Data Type Historic
Creating Hourly Time Series File
_ Loading Time Series File;C:1KC SwpM1KC
DATA\STTP60H.rnf
Till Pasture 6.19 acres
Loading Time Series File: C:\KC_SWDM\KC_DATA\STTG6DH.rnf
Till Grass 1.74 acres
Loading Time Series Fi:.e:C:\KC_SWDM\KC_DATA\STEI60H.rnf
Impervious 4.28 acres
--------------
Total Area 12.23 acres
Peak Discharge: 2.70 CFS at 6:00 on Jan 9 in 1990
Storing Time Series File:dov.tsf
Time Series Computed
KCRTS Command
-------------
CREATE a new Time Series
------------------------
Production of Runoff Time Series
Project Location : Sea-Tac
Computing Series : bypass.tsf
Regional Scale Factor : 1.00
Data Type : Historic
Creating Hourly Time Series File
Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H_rnf
Till Grass 0.25 acres
--------------
Total Area 0.25 acres
Peak Discharge: 0.D53 CFS at 16:00 on Mar 3 in 1950
Storing Time Series File:bypass.tsf
Time Series Computed
KCRTS Command
-------------
Enter the Analysis TOOLS Module
-------------------------------
0 Analysis Tools Command
•
•
Compute -PEAKS -and -Flow -Frequencies
Loading Time Series File:exist.tsf
Flow Frequency Analysis LogPearson III Coefficierts
--------------------------------------------------------
Time Series File:exist.tsf Mean= -0.346 StdDev= 0.202
Project Location:Sea-Tac Skew= 0.037
Frequencies & Peaks saved to File:exist.pks
Analysis Tools Command
----------------------
Compute PEAKS and Flow Frequencies
------------------------------------
Loadirg Time Series File:dev,tsf
Flow Frequency Analysis LogPearson III Coefficients
--------------------------------------------------------
Time Series File dev.tsf Mean= 0.140 StdDev= 0-120
Project Location:Sea-Tac Skew= 0.391
Frequencies & Peaks saved to File:dev.pks
Analysis Tools Command
----------------------
Compute PEAKS and Flow Frequencies
-------------------
Loading Time Series File:bypass.tsf
Flow Frequency Analysis LogPearson III Coefficients
----------------------------------------------------------
Time Series File:bypass.tsf Mean=-1,791 StdDev= 0.213
Project Location:Sea-TaC Skew= 0.249
Frequencies & Peaks saved to File:bypass.pks
Analysis Tools Command
----------------------
RETURN to Previous Menu
-----------------------
KCRTS Command
-------------
eXit KCRTS PrOgram
----------------
�✓k
•
•
0
KCRTS Program -File Directory:
C:IKC_SWDM%KC_DATA\
[C] CREATE a new
Time Series
ST
5.72
0,00
0,000000 Till Forest
6.19
0.00
0.000000 Till Pasture
0.00
0.00
0.000000 Till Grass
0.00
0.00
0.000000 Outwash Forest
0.00
0.00
0.000000 Outwash Pasture
0.00
0.00
0.000000 Outwash Grass
0,00
0.00
0.000000 Wetland
0.55
0.00
0.000000 Impervious Q.5
exist.tsf
F
1.00000
T
[C] CREATE a new
Time Series
ST
0.00
0.00
0.000000 Till Forest
6.19
0.00
0.000000 Till Pasture (. L
1.74
0,00
0.000000 Till Grass 1.52.
0,00
0.00
0.000000 Outwash Forest
0.00
0,00
0.000000 Outwash Pasture
0.00
0.00
0.000000 Outwash Grass
0,00
0.00
0.000000 Wetland
4,28
0.00
0.000000 Impervious q,13
dev.tsf
F
1.00000
T
[C] CREATE a new
Time Series
ST
0.00
0.00
0.000000 Till Forest
0.00
0.00
0.000000 Till Pasture
0.25
0.00
0,000000 Till Grass 0110
0.00
0.00
0.000000 Outwash Forest
0.00
0.00
0.000000 Outwash Pasture
0.00
0.00
0.000000 Outwash Grass
0.00
0.00
0.000000 Wetland
0.00
0.00
0.000000 Impervious
bypass.tsf
F
1.00000
T
M Enter the Analysis TOOLS Module
[P] Compute PEAKS and Flow Frequencies
exist.tsf
exist.pks
[P] Compute PEAKS and Flow Frequencies
dev.tsf
dev.pks
[P] Compute PEAKS and Flow Frequencies
bypass.tsf
bypass,pks
[R] RETURN to Previous Menu
[X] eXit KCRTS Program
j) 414.1--Y
�4 � �
AMA, n'-9000
�'
rf�22 -ur AAE& N 2e r
1 fA TD �, L.(,- I
•
L`
0
Wehrman Plat
Runoff Calcs compare offsite flows to fully developed onsite flows to
determine need for bypass.
7/29/08
Flow Frequency Analysis
Time series File:offsite.tsf
Project tocation:sea-Tac
---Annual
Peak
Flow Rates ---
Flow Rate
Rank
Time of
Peak
(CFS)
0,520
3
2/09/01
15:00
0.270
7
1/05/02
16:00
0.524
2
2/28/03
3:00
0.152
8
8/26/04
2:00
0.301
6
1/05/05
8:00
0.501
4
1/18/06
16:00
0.476
5
11/24/06
4:00
0.985
1
1/09/08
6:00
computed Peaks
Flow Frequency Analysis
Time Series File:devsite.tsf
Project Location:sea-Tac
--Annual Peak Flow Rates ---
Flow Rate Rank Time of Peak
(CPS)
1.01
6
2/09/01
2:00
0.836
8
1/05/02
16:00
1.22
3
2/27/03
7:00
0.913
7
9/26/04
2:00
1.10
4
10/28/04
16:00
1.08
5
1/18/06
16:00
1.33
2
10/26/06
0:00
2.05
1
1/09/08
6:00
computed
Peaks
-----Flow
Frequency
Analysis --------
- - Peaks
- - Rank
Return
Prob
(CFS)
period
0.985
1
100.00
0.990
0.524
2
25.00
0.960
0.520
3
10.00
0.900
0.501
4
5.00
0,800
0.476
5
3.00
0.667
0.301
6
2.00
0.500
0.270
7
1.30
0.231
0.152
8
1.10
0.091
0.832
50.00
0.980
-----Flow
Frequency
Analysis-------
- - Peaks
- - Rank
Return
Prob
(CFS)
Period
2.05
1
100.00
0.990
1,33
2
25.00
0,960
1.22
3
10.00
0.900
1.10
4
5.00
0.800
1.08
5
3.00
0.667
1.01
6
2.00
0.500
0.913
7
1.30
0.231
0.836
8
1,10
0.091
1.81
50.00
0.980
Existingg upstream (Offsite) 100-year Q = 0.985 cfs
50% of 100-year Developed (undetained) Q = 0.5n2.05 = 1.025 cfs
0.985cfs < 1.025cfs; therefore, no need to bypass offsite flows.
KCRTS Program...File
Directory:
C:\KC_SWDM\KC_DATA\
[C]
CREATE a new
Time Series
ST
40
0.00
0100
0.000000
Till Forest
6.20
0,00
0,000000
Till Pasture
0.00
0.00
0.000000
Till Grass
0.00
0.00
0.000000
outwash Forest
0.00
0.00
0.000000
outwash Pasture
0.00
0.00
0.000000
outwash Grass
0.00
0.00
0.000000
wetland
0.50
0.00
0.000000
Impervious
offsite.tsf
T
1.00000
T
[C]
CREATE a new
Time Series
ST
0.00
0,00
0.000000
Till Forest
0.00
0.00
0,000000
Till Pasture
1.79
0.00
0.000000
Till Grass
0.00
0.00
0.000000
Outwash Forest
0.00
0.00
0.000000
outwash Pasture
0.00
0.00
0.000000
outwash Grass
0.00
0.00
0.000000
wetland
3.53
0.00
0,000000
Impervious
devsite.tsf
T
1.00000
T
[T] Enter the Analysis TOOLS Module
[P] Compute PEAKS and Flow Frequencies
offsite.tsf
offsite.pks
[[P] compute PEAKS and Flow Frequencies
devsite.tsf
devsite.pks
[R] RETURN to Previous Menu
[x] exit KCRTS Program
•
0
j MPU-T- DATA f b� Xr S j TE
FL 0,AJ C,0i' j s a tJ
APPENDIX C-1
DETENTION FACILITIES DESIGN
•
•
hrman
Wetenti Plat
Retention/Detention
Facility
Tyne of Facility:
Detention
Pond
Side Slope:
3.00
H;1V
Pond Bottom Length:
180.00
ft
Pond
Bottom width:
55.00
ft
Pond
Bottom Area:
9900,
sq. ft
Top Area
at 1 ft. FS:
19656.
sq. ft
0.451
acres
Effective Storage Depth:
5.00
ft
Stage
0 Elevation:
0,00
ft
Storage Volume:
68625.
cu. ft
1.575
ac-ft
Riser Bead;
5.00
ft
Riser Diameter:
12.00
inches
Number
of orifices:
2
Full Head
Pipe
Orifice
# Height
Diameter
Discharge
Diameter
(ft)
(in)
(CFS)
(in)
1
0.00
2.10
0.267
2
3.00
3,2C
0.393
6.0
Top Notch Weir:
None
Outflow
Rating Curve:
None
Stage
Elevation
Storage
Discharge
Percolation
Surf Area
(ft)
(ft) (cu.
ft) (ac-ft)
{cfs)
(cfs)
(sq. ft)
0.00
0.00
0.
0,000
0.000
0.00
9900,
O.D2
0,02
198.
0.005
0.018
0.00
9928.
0.04
0.04
397.
0.009
0.025
0.00
9956.
0.07
0.07
697_
0.016
0.031
0.00
9999.
0.09
0.09
897.
0,021
0,035
0.00
10027.
0.11
0,11
1098.
0.025
0.040
0.00
10056,
0.13
0.13
1299.
0,030
0.043
0.00
10084,
0.15
0.15
1501.
0.034
0.047
0,00
10112,
0.17
0.17
1703.
0.039
0.050
0.00
10141,
0.20
0.20
2008.
0.046
0.053
0.00
10183.
0.30
0.30
3034.
0,070
0.065
0.00
10326.
0.40
0.40
4374.
3.094
0.075
0.00
10470,
0.50
0.50
5128.
0.118
0.C64
0.00
10614.
0.60
0.60
6196.
0.142
0,092
C.00
10759.
0.70
0.70
7280_
0.167
0,100
0.0C
109C5.
0.80
0.80
8377.
0.192
0.107
0.00
11051.
0.90
0.90
9490.
0.218
0,113
0.00
11198.
1.00
1.00
10617.
C.244
0.119
C.00
11346.
1.10
1.10
11759.
0,270
0.125
0.00
11495,
1.20
1.20
12916,
0.297
0.131
0.00
11644.
1.30
1.30
14088.
0,323
0,136
0.00
11794.
1.40
1.40
15275.
0.351
0.141
0.00
11945,
1.50
1.30
16477.
C.378
0.146
0.00
12096.
1.60
1.60
17694.
0.406
0.151
0.00
12246,
1.70
i.70
18926.
0,434
0.156
0.00
12401.
1.80
1.80
20174.
0.463
0.160
0.00
12555.
1.90
1,90
2i437.
0.492
0.165
0,00
12709.
2.00
2.00
22716,
D.521
0.169
0.00
12864.
2.10
2.13
24010,
0.551
0.173
0.00
13020,
2.20
2.20
25320.
0.581
0.177
0.03
13176.
2,30
2.30
26645.
0.612
0.181
0.00
13333.
2.40
2,40
27987,
0,642
D.185
0,00
13491.
2,50
2.50
29344.
0.674
0.189
O.OD
13650.
2.60
2.60
30717,
0.705
0.193
0.00
13809_
2,70
2.70
22106.
0.737
0.196
0.00
13969.
2.80
2.80
33511,
0,769
D.200
0.00
14130.
2,90
2.93
34932.
0.602
0,204
0.00
14292.
3.00
3,00
36369.
0,835
0.207
0.00
14454.
3.03
3.03
36803.
0.845
0.211
0.0D
14503.
3,07
3.10
3,07
3.10
17381,
37823.
1,111
0.868
0,220
0.234
1,CO
0.00
14568,
14617.
3.13
3.13
28262,
0,878
0.252
0.00
14666.
212
3,17
3.17
38850.
0.892
C.276
0.00
14731.
3.20
3.20
39292.
0,902
C,304
0.00
14781,
3.23
3.23
39737.
0,912
0,333
MO
14630,
3.27
3.27
40331.
0.926
0.360
0.00
14896,
3.30
3.30
40779.
0.936
0.369
0.00
14945.
3.40
3.40
42281,
0.971
0,396
0.00
15110,
3.50
3.50
43801.
1.006
0.420
0.00
15276.
3.60
3.60
45337.
1,041
0.442
0.00
15443,
3.70
3.70
46889.
1.076
0.462
0.00
15610.
3.80
3.60
48459.
1.112
0.482
0.00
15778,
3,90
3.90
50045.
1.149
0.500
0.00
15947.
4.00
4.00
51648.
1,186
0,517
0.00
16116.
4.10
4.10
53268.
1.223
0.534
0.00
16286.
4.20
4.20
54905.
1.260
0,549
0.00
16457.
4.30
4.30
56560,
1.298
0,565
0.00
16629.
4.43
4,40
58231.
1.337
0.580
0.00
16601,
4.50
4.50
59920.
1.376
0.594
0.00
16974.
4.60
4.60
61626,
1.415
O.E08
0.00
17148.
4.70
4,70
63349.
1.454
9.621
0.00
17322.
4.80
4.80
65090.
1.494
0.635
0.00
17497.
4.90
4.90
66849.
1.535
0.648
0.00
17673.
5.00
5.00
68625.
1.575
0.660
0.00
17850.
5.10
5.10
70419.
1.617
0.981
0.00
18027,
5.20
5.20
72230.
1.658
1.560
0.00
18205.
5,30
5.30
74060.
1.700
2.300
0.00
18384.
5,40
5.40
75907.
1.743
3.100
0.00
18564.
5.50
5.50
77773.
1,785
3.390
0.00
18744.
5.60
5.60
79656.
1.829
3.660
0.00
13925.
5.70
5.70
81558.
1.672
3.910
9.00
19107.
5.80
5.80
83478.
1.916
4.140
0.00
19289,
5.90
5.90
85416.
1.961
4.350
0.00
19472.
6.00
6.00
87372.
2.006
4.560
0100
19656.
6.i0
6.10
89347.
2.051
4.750
0.00
19841.
6.20
6.20
91340,
2.091
4.940
0.00
20026.
6.30
6.30
93352.
2.143
5.120
0.00
20212,
6.40
6.40
95383.
2,190
5.290
0100
20399.
6.50
6.50
97432,
2.237
5.460
0.00
20586.
6.60
6.60
99500.
2.284
5.620
0.00
20774.
6.70
6.70
101587.
2.332
5.780
0.00
20963.
6.80
6.80
103692.
2.380
5.930
0.00
21153.
6.90
6.90
105817.
2.429
6.080
0.00
21343.
7.00
7.00
1C7961.
2.478
6.220
0.00
21534.
Hyd
Inflow
Outflow
Peak
Storage
Stage
E1ev
{C•a-Ft}
IAc-Ft}
1
1.57
1.13
5,13
5.13
70674.
1.627
2
1.82
1.08
5.12
5.12
70720,
1.623
3
2.7C
0.83
5.05
5.05
69600.
1.598
4
1.80
0.60
4.52
4.52
60215,
1.382
5
2.35
0.59
4.47
4.47
59412.
1.364
6
1.57
0.52
4,03
4.03
52'-50.
1."197
7
1.18
0,32
3,22
3.22
39611,
0.909
8
1.04
0.19
2.62
2.62
30980.
C.711
Hyd
R/D Facility
Tributary Reservoir
POC Outflow
Outflow
Inflow
Inflow
Target
talc
1
1.13
0.02 ********
1.35
1.14
2
1.08
0.03 *+**+*** *******
1.09
3
0.83
0.05 ******** *******
0.85
4
0.60
0.02 ******** *******
0.61
5
0.59
0.03 ***w*xxx xxx***+
0.60
6
0.52
0.02 ******** *******
0.53
7
0.32
0.01 ******** *******
0.33
8
0,19
0.01 *x**xxxx ***x**.
0.20
----------------------------------
Route Time Series through Facility
Inflow Time Series File:dev.tsf
Outflow Time Series File:rdout
FOC Time Series File:dsout
312
Inflow/Outflow Analysis
Peak
Inflow Discharge:
2.?0
CFS at
6:00 on
,Ian
9 in 1990
Peak Outflow
Discharge:
1.13
CFS at
19:00 on
Feb
9 in 1951
Peak
Reservoir Stage:
5.13
Ft
Peak Reservoir E1ev:
5.13
Ft
Peak Reservoir
Storage:
70874.
Cu-Ft
1.627 Ac-Ft
Add Time
Series:bypass.tsf
Peak Summed Discharge:
1.14
CFS at
19.00 on
Feb
9 in 1951
Point of
Compliance File:dsout.tsf
Flow Frequency Analysis
LogPearson III
Coefficients
Time Series File•rdout.tsf
Mean- -0.5C3
StdDev=
0.231
Project Location.Sea-Tac
Skew= 0.452
---,Annual Peak
Flow Rates---
-----Flow Frequency
Analysis-------
FlowRate
Rank
Time of
Peak
- - Peaks - -
Rank
Return
Prob
{CFS)
(CFS)
(ft)
Period
0,193
39
2/17/49
9:00
1.13
5.13
1
89,50
0.989
0.412
14
3/05/50
5:00
1,Q8
5.12
2
32.13
0.969
1.13
1
2/09/51
19:00
0.834
5.05
3
19.58
0,949
0.172
45
2/01/52
4:00
0.649
4.91
4
14,08
0.929
0.194
37
1/12/53
7:00
0.633
4.79
5
10,99
0,909
0.371
19
1/06/54
7:00
0.596
4.52
6
9,01
0.889
0.406
15
2/OB/55
3:00
0.590
4.47
7
7.64
0.869
0.456
12
1/06/56
10:00
0.552
4.22
8
6.63
0.849
0.273
30
2/26/57
3:00
0.542
4.15
9
5.86
0.829
0.367
22
1/17/58
7:00
0.522
4.C3
10
5.24
0.809
0.201
32
1/24/59
16:00
0.520
4.02
11
4.75
0,789
0.633
5
11/21/59
3:00
0.456
3.67
12
4.34
0.769
0.325
26
11/24/60
11:00
0.442
3.60
13
3.99
0.749
0.165
47
1/03/62
9:00
0.412
3.47
14
3.70
0.729
0.314
27
11/26/62
10:00
0.408
3.45
15
3.44
0,709
0.205
31
1/02/64
0:00
0.384
3.36
16
3.22
0.690
0.376
18
12/01/64
2:00
0.380
3.34
17
3.03
0.670
0.197
36
12/28/65
18:DO
C.376
3.33
16
2.85
0.650
0.380
17
12/13/66
9:00
C.371
3.31
i9
2.13
0,630
0.199
34
1/20/68
20:00
C,371
3.31
20
2.56
0.6i0
0.193
38
12/04/68
3:00
0.371
3.31
21
2.44
0,690
0.200
33
1/14/70
17:00
0.367
3.25
22
2.32
0.570
0.361
23
12/07/70
4:00
C.361
3.27
23
2.22
0.550
0.542
9
2/28/72
7:00
0.360
3.27
24
2.13
0.530
0.295
29
12/26/72
19:00
0.342
3.24
25
2.04
0.510
0.360
24
1/16/74
17:00
0.325
3.22
26
1.96
0.490
0.371
21
12/27/74
7:00
0.314
3.21
27
1.89
0.470
0.371
20
12/04/75
1:00
0.309
3.21
28
1.62
0.450
0.142
50
8/26/77
6:00
0.295
3.19
29
1.75
0.430
0.342
25
12/15/77
18:00
0,273
3.16
30
1.70
0.410
0.159
48
2/12/79
17:00
0.205
2.95
31
1.64
0.290
0.522
1C
12/15/79
13:00
0,201
2.83
32
1.59
0.370
0.198
35
12/27/80
8:00
0.200
2.B0
33
1.54
0,350
0.590
7
10/06/81
18:00
C.199
2,78
34
1.49
0.330
0.384
16
1/05/63
15:00
0.198
2.75
35
1.45
0.310
0.179
44
12/10/83
18:00
0.197
2.72
36
1.41
0.291
0.163
43
11/04/84
0:00
0.194
2.62
37
1.37
0.271
0.552
8
1/18/86
23:00
0.193
2.61
38
1.33
0.251
0.596
6
11/24/86
8:00
0.193
2.61
39
1,30
0,231
0.188
42
1/15/80
6:00
0.192
2.56
40
1.27
0.211
0.168
46
11/05/88
21:00
0.190
2.53
41
1.24
0.191
0.834
3
1/09/90
11:00
C.186
2.47
42
1.21
0.171
0.649
4
4/05/91
6:00
0.183
2.35
43
1.18
0.151
0,309
28
1/30/92
9:00
0,179
2.26
44
1.15
0.131
0.192
40
3/23/93
12.00
0.172
2.08
45
1.12
(),Ill
C,144
49
2/17/94
21:00
0.168
1.97
46
1.10
0.091
0.442
13
2/19/95
22:00
0.165
1,69
47
1.08
0.071
1.08
2
2/09/96
2:00
C,159
1.77
48
1.05
0.051
0.520
11
1/02/97
12.00
0.144
1.46
49
1.03
0,031
0.19C
41
10/30/97
12:00
0.142
1.42
50
1.01
0.011
Computed
Peaks
1,29
5.15
100.00
0.990
Computed
Peaks
1.06
5.il
50.00
0.960
Computed
Peaks
0.863
5.06
25.00
0.960
419
Computed
Peaks
3.635
4.80
10.00
0.900
Computed
Peaks
0.594
4.50
8.00
0.875
Computed
Peaks
0.4B5
3.81
5.00
O.BOO
Computed
Peaks
0.202
3,20
2.00
0.500
Computed
Peaks
0,208
3.01
1.30
0.231
Flow Frequency Analysis
LogPearson
Ill Coefficients
Time Series File:dsout.tsf
Mean-
-0.493 Stdoev=
0.230
Project
Location:Sea-Tac
Skew= 0.448
---Annual Peak
Flow Rates---
-----Flow
Frequency
Analysis-------
FlowRate Rank
Time cf
Peak
- Peaks
- - Rank
Return
Prob
(CFS}
(CFS)
Period
0.199
38
2/17/49
9:00
1.14
1
89.50
0.989
0.419
14
3/05/50
5:00
1.09
2
32.13
0.969
1.14
1
2/09/51
19:00
0.848
3
19.58
0.949
0.177
45
1/30/52
16:00
0.664
4
14.08
0.929
0.198
39
1/12/53
7:00
0.648
5
10.99
0.909
0,379
20
1/06/54
7:00
0.610
6
9.01
O.8B9
0.418
15
2/C8/55
2:00
0.603
7
7.64
3,669
0.464
12
1/06/56
10:00
0.566
B
6.63
0.849
0.278
30
2/26/57
2:0D
0.554
9
5.86
0.829
0.374
22
1/17/58
6:00
0.533
10
5.24
0.809
0,207
32
1/24/59
14:00
0.529
11
4.75
0.789
0.646
5
11/21/59
2:00
0.464
12
4.34
0.769
0.332
26
11/24/60
11:00
0.452
13
3.99
0,749
0,169
47
1/03/62
8:00
C.419
14
3.70
0.729
0.320
27
11/26/62
10:00
C.418
15
3.44
0,709
0.212
31
1/02/64
0:00
0.394
16
3.22
0.690
0.364
18
12/01/64
2:00
0,389
17
3.03
0.670
0.202
36
12/28/65
18:00
0.384
18
2.85
0.650
0.389
17
12/13/66
9:00
0,260
19
2.'10
0.633
0.205
34
1/20/68
20:00
0,379
20
2.56
0.610
0.200
37
12/04/68
1:00
0.378
21
2.44
0.590
0.206
33
1/14/70
15:00
3.374
22
2.32
0.570
0.368
23
12/07/70
4:00
0.368
23
2.22
0,550
0.554
9
2/28/72
7:00
0.367
24
2.13
0.530
0.302
29
12/26/72
19:00
0.349
25
2.04
0.510
0.367
24
1/16/74
17:00
0,332
26
1.96
0.490
0.380
19
12/27/74
7:00
0.320
27
1.89
0.470
0.378
21
12/04/75
1:00
0.315
2B
1.82
0.450
0.144
50
8/26/77
6:00
0.302
29
1.75
0.430
0.349
25
12/15/77
18:00
0.278
30
1.70
0.410
0.163
48
2/12/79
18:00
0.212
31
1.64
0.390
0.533
10
12/15/79
12:00
0.207
32
1.59
0.37D
0.203
35
12/27/60
7:00
0.206
33
1.54
0.350
0.603
7
10/06/81
16:00
2,205
34
1.49
01330
0.394
16
1/05/63
15:00
0.203
35
1.45
0.310
0.184
44
12/10/83
18:00
3.202
36
1.41
0.291
0.107
43
11/03/84
23:00
0.200
37
1.37
0.271
0.566
B
1/18/86
23700
0.199
36
1.33
0,251
0.610
6
11/24/86
8:00
0.198
39
1.30
0.231
0.192
42
1/15/88
6:00
0.198
40
1.27
0,211
0.172
46
11/05/88
21:DO
0.196
41
1.24
0.191
0.848
3
1/D9/90
11:00
0.192
42
1.21
0.i71
0.664
4
4/05/91
6:00
0.187
43
1,18
0.151
0.315
28
1/30/92
9:OC
0.184
44
1.15
0.131
0.198
40
3/23/93
9:00
0.177
45
1.12
0.111
0.147
49
2/17/94
20:00
0,172
46
1.20
0.091
0.452
13
2/19/95
22:00
0.169
47
1.08
0.071
1.09
2
2/09/96
2:00
0.7-63
48
1.05
0.051
0,529
11
1/02/97
12:OC
0,147
49
1.03
0.031
C.196
41
10/30/97
12:OC
0.144
50
1.Di
0,011
Computed
Peaks
1.31
100.00
0.990
Comnuted
Peaks
1.08
50.00
0.980
Computed
Peaks
0.677
25.00
0.960
Computed
Peaks
0.647
10.00
0.900
Computed
Peaks
0.605
8.00
0.875
Computed
Peaks
0.495
5.0D
0.800
Computed
Peaks
0.309
2.00
0.500
Comnuted
Peaks
0.213
1.30
0.231
5/2
Flow Duration from Time Series File:rdcut.t5f-
C�torf Count Frequency CDF Exceedence Prol-ability
CFS % %
0.016 298015 68.040 68.040 31.960 0.320E+00
0.047 44834 10.236 78.276 21.724 0.217E+CD
0.079 38471 8,783 67.059 12.941 0,129E+00
0.110 23763 5.425 92.485 7,515 0,752E-01
0.142 15776 3.602 96.087 3.913 0.391E-01
0.173 9297 2.123 98.209 1.791 0,179E-01
0.205 5175 1.182 99.391 0,609 0.639E-C2
0.236 1042 0.238 99.629 0.371 0,371E-02
C.267 267 0.061 99.689 0,311 0.311E-02
0.299 207 0.047 99.737 0.263 0.263E-02
0.330 131 0.030 99.767 0,233 0.233E-02
0.362 148 0.034 99.800 0.200 0.200E-02
0.393 193 0.044 99.845 0.155 0.155E-02
0.425 135 0.031 99.875 0.125 0,125E-02
0.456 122 0,028 99.903 0.097 0.968E-03
0.4B8 86 0.020 99.923 0.077 0.772E-03
0.519 87 0.020 99.943 D.057 0.573E-03
0.550 68 0.016 99.958 0.042 0.418E-03
0.582 52 0.012 99.970 0.030 0.299E-03
0.613 58 0.013 99.983 0.017 0.167E-03
0.645 3B 0.009 99.992 0.00E 0,799E-04
0,676 19 0.004 99.996 0.004 0,365E-04
0,708 2 0,000 99.997 0.003 0.320E-04
0.739 1 0,000 99.997 0.003 0.297E-04
0.771 2 0.000 99.997 0.003 0.251E-04
0.802 1 0.000 99.99E 0.002 0.228E-04
0.833 1 0.000 99.99E 0.002 0.205E-04
0.865 3 0.001 99.999 0.001 0.137E-04
0.896 1 0.000 99.999 0.001 0.114E-04
0.928 0 0.000 99.999 0.00i 0.114E-04
0.959 0 0.000 99.999 0.001 0.114E-04
0,991 2 0.000 99.999 0.001 0.685E-05
1,02 1 0.000 100.000 0.000 0.457E-05
1.05 0 0.000 100,00C 0.000 0.457E-05
1.08 1 0.000 100.000 0.000 0.22BE--05
1.12 0 0.000 100.000 0.000 0.228E-05
Flow Duration from Time Series File:dsout.tsf
Cutoff Count Frequency CDF Exceedence_Probability
CFS % % %
0.016 298271 68.09E 68.096 31.902 0.319E+00
0,048 44865 10.243 78.342 21.65E 0,217E+00
0.080 38150 6.710 87.052 12.948 0.129E+00
0.112 23412 5.345 92.397 7.603 3.760E-01
0.143 15867 3,623 96.019 3.981 0.398E-01
0.175 9280 2.119 98.138 1.862 0.186E-01
0.207 5262 1,201 99.340 0.661 0.661E-02
0.239 1221 0.279 99.616 0.382 0.382E-02
0.271 298 0.068 99.686 0.314 0.314E-02
0.302 201 0.046 99.732 0.268 0.268E-02
0.334 142 0.032 99.765 0.235 0,235E-02
0.366 138 0.032 99.796 0.204 0.204E--02
0.398 195 0.045 99.841 0.159 0.159E-02
0.430 137 0.031 99.872 0.128 0.12BE-02
0.461 121 0.028 99.900 0.100 0.100E-02
0.493 89 0,020 99.920 0.080 0.801y-03
0.525 87 0.020 99,940 0.060 0.603E-03
0.557 67 0.015 99.955 0.045 0,450E-03
0.589 54 0.012 99.967 0.033 0.326E-03
0.620 63 0,014 99.982 0.018 0.183E-03
0.652 36 0,00E 99.990 0.010 0.100E-03
0.684 28 0.006 99.996 0.004 0,365E-04
0,716 0 0.000 99.996 0.004 0.365E-04
0.748 3 0.001 99.997 0.003 0.297E-04
0,779 2 0.000 99.997 0.003 0.251E-04
0.811 1 0,000 99.998 0.002 0.228E-04
0,843 1 0.000 99.998 0.002 0.205E-04
0.875 2 0.000 99.998 0.002 0,160E-04
lit
0
0
0,907 2 0.000 99.999 0.001 0.114E-04
0.938 O 0.000 99.999 0.001 0.114E-04
0.970 0 0.000 99.999 0.301 0.114E-04
1.00 i 0.000 99,999 0.001 0.913E-05
1.03 2 0.000 100,000 0.000 0.457E-05
1.07 0 0.000 100.000 0.000 0.457E-05
1.10 1 0.000 100,000 0.000 0.228E-05
1.13 0 0.000 10D.000 0.000 0.22BE-05
Duration Comparison Anaylsis
Base File: exist.tsf
New File: dsout.tsf
Cutoff Units: Discharge in CFS
-----Fraction of Time ----- ---------Check of Tolerance -------
Cutoff Base New %Change Probability Base New %Change
0.224 0.66E-02 0.43E-02 -35.5 1 0.66E-02 0.224 0.207 -7,5
0.296 0.32E-02 0.27E-02 -14.1 1 0.32E-02 0.296 0.268 -9.4
0.367 i 0,17E-02 0.20E-02 18.2 1 0,17E-02 0.367 0.387 5.3
0.439 I 0.91E-03 0.12E-02 32.5 1 0.91E-03 0.439 0.474 7.8
0.511 i 0.53E-C3 0.69E-03 30.0 I 0,53E-03 0.511 0.536 4.8
0.583 1 0.33E-03 D.35E-03 4.1 1 0.33E-03 0.583 0.566 0.6
0.654 i 0.20E-03 0.89E-04 -55.7 1 0,20E-03 0.654 0.611 -6.6
0.726 i 0.96E-04 0,32E-04 -66.7 j 0.96E-04 0.726 0,653 -10.1
0.798 I 0.55E-04 0.25E-04 -54.2 1 0.55E-04 0.798 0.667 -16.3
0.869 I 0.30E-04 0.16E-04 -46.2 k 0.30E-04 0.869 0.755 -13.1
0.941 I 0.14E-04 0.11E-04 -16.7 k 0,14E-04 0.941 0.863 -6.2
1.01 i 0.14E-04 0.68E-05 -50.0 [ 0,14E-04 1.01 0.883 -12.8
1.08 I 0.11E-04 0.46E-05 -60.0 1 0.11E-04 1.08 0.990 -8.7
1.16 i 0.23E-05 0.00E+00 -100.0 I 0,23E-05 1.16 1.14 -1.6
Maximum positive excursion = 0.039 cfs { 8.7%)
occurring at 0.453 cfs on the Base Data:exist.tsf
and at 0.492 cfs on the New Data:dsout,tsf
Maximum negative excursion = 0.178 cfs (-20.8%)
occurring at 0.858 cfs on the Base Data;exist.tsf
and at 0.680 cfs on the New Data:dscut.tsf
n �
J
I 1
•
(SJO) a5jeuasia
E
Riser Overflow and Secondary Inlet "Jailhouse Window"
(iteratively sizes the flow control riser and a "jailhoese window" secondary
inlet using the sharp crested weir eqn.)
Project: Wehrman Plat
Date: 1018l2008
By: LT
Rectangular, Sharp Crested Weir
Q = C (L - 0.2H) H"3/2
C = 3.27 * 0.40HIP
Q(100) =103 cfs
H
P
L
C
Q
0,46
4.5
3.1
3.3
3.15
0.46
4.5
3.1
3.3
3.11
12" riser
Jailhouse Window
See Erosion Control Calculations for Emergency Overflow Spillway Sizing
Drainage C2IC5 MW.xis Jailhouse Window
Printed: 101812008
•
APPENDIX C-2
TREATMENT FACILITIES DESIGN
IE
Treatment Pond Sizing Routine
Project: Wehrman Piat
Treatment Pond
Date: 2/2812012
Blue represents manual entry fields
Red represents calculated fields
Step 1: Wetpool volume factor (f)
...either 3 or 4.5
f= 3
Step 2: Mean annual rainfall (R)
...from Fig. 6.4.1.A, pg 6-69
R = 0.47 in
Step 3: Runoff (Vr)
... V r=(0.9Ai+0.25Atg+0.10Atf+0.01 Ao)xR/12
Ai = 151.173 sf
Atg = 65,095 sf
Atf = 0 sf
Ao = 0 sf
Vr = 5,966 cf
Step 4: Wetpool volume (Vb)
...Vb=fVr
Vb = 17,899 cf
Step 5: Wetpool dimensions
...Vb=h(A1+A2)12 Solve by trial & error
Al = 6,608 sf
L = 47 ft
3f_ = 141 ft
h= 4ft
S= 3ft
A2 = 2,678 sf
'Vb = 18,573 of
If Vb calculated in Step 5 < Vb from Step 4, then increase h
Cell 1 must contain 25% - 35% of total Wetpool volume
Cell 1 required volume between 4,643 and 6,501 cf
Cell (47x47) Cell (47x160)
Al = 2,200 sf Al = 7,532 sf
h= 4ft h= 2ft
S= 3ft S= 3ft
A2 = 525 sf A2 = 5,593 sf
V = 5,449 cf V = 13,125 cf 'Vb = 18,574 cf
This spreadsheet determines the required size and geometry for the wetpool.
The physical constraints of the site and the detention sizing requirements will change the treatment pond
dimensions; however, these minimum parameters must be met.
Drainage Calcs MW.xlsx (Treatment Pond )
2/28/2012
•
APPENDIX C-3
EROSION CONTROL FACILITIES DESIGN
•
•
1/4
KCRTS Program... File Directory:
KC_SWDM\KC—DATA\
CREATE a new Time Series
ST
0.00 0.00
0,000000
Till Forest
6.20 0.00
0.000000
Till Pasture
1.79 0.00
0.000000
Till Grass
0.00 0.00
0.000000
Outwash Forest
0.00 0.00
0.000000
Outwash Pasture
0.00 0.00
0.000000
Outwash Grass
0.00 0.00
0.000000
wetland
4.03 0.00
0.000000
Impervious
devl5.tsf
T
1.00000
F
(T Enter the Analysis TOOLS
Module
rrPi Compute PEAKS and Flow Frequencies
devl5.tsf
dev15.pks
to Previous Menu
NRETURN
exit KCRTS Program
•
•
S1 a" Ck)"—r� �— c S .
14
Flow Frequency Analysis
Time Series
File:devl5.tsf
Project
Location:sea-Tac
---Annual
Peak
Flow Rates ---
Flow Rate
Rank
Time of Peak
(US)
1.92
6
8/27/01 18:00
1.48
8
1/05/02 15:00
4.79
Z
12/08/02 17:15
1.55
7
8/23/04 14:30
2.33
5
11/17/04 5:00
2.39
4
10/27105 10:45
2.69
3
10/25/06 22:45
6.95
1
1/09/08 6:30
computed
Peaks
- -Pt,r�d C,.-fC �,-
'SA - ZD90 Q z
r Wcbo (1 �I2-)
31lei4 41
0
-----Flow
Frequency
Analysis -------
- - Peaks
- - Rank
Return
Prob
(CFS)
Period
6.95
1
100.00
0.990
4.79
2
25.00
0.960
2.69
3
10.00
0.900
2.39
4
5.00
0.800
2.33
5
3.00
0.667
1.92
6
2.00
0.500 6r
1.55
7
1.30
0.231
1.48
8
1.10
0.091
6.23
50.00
0.980
•
•
EC Pond Calculations
Project: Wehrman Plat
Date: 6-Oct-08
Q2 =
1.92 cfs
Q10 =
2.69 cfs
Qioo =
6.95 cfs
Determine Pond Geometry
SA = 2080*Q2
SA = 3,994 sf
Size Discharge Mechanisms
(from KCRTS flow frequency analysis)
(from KCRTS flow frequency analysis)
(from KCRTS flow frequency analysis)
- Principal Spillway
Must be at least 10" diameter to pass Q10 @ T head(from KCSWDM Fig 5.3.4.H)
=> If permanent control structure is used for EC, then riser must be at least 10"
- Emergency Overflow Spillway - iterative solution below
L=((Q100/3.21 *HA(3/2))-(2.4*H)
H
L
0.2
23.7
0.3
12.5
0.4
7.6
0.5
4.9
0.6
3.2
0.7
2.0
0.8
1.1
6' minimum length is req'd
- Dewaterina Orifice
Ao=4.81 *(10-6)*Ao*sgrt(h)
AO = 0.01 sf
D=13.54*sq rt(Ao)
D = 1.68 in
Drainage Calcs MW.xls EC Calcs
1016f2008
•
C,
E
SECTION 5.3 DETENTION FACILITIES
Riser Overflow
The nomograph in Figure 5.3 AH may be used to determine the head (in feet) above a riser of given
diameter and for a given flow (usually the I00-year peak flow for developed conditions).
100
FIGURE 5.3.4.H RISER INFLOW CURVES
p
IF
ZMAM/A
NNEW
osim
P,
milli
0
PA
0111
DA HEAD IN FEET (measured from crest of riser) 10
Qwo,r=9.739 DH"
Q o,n,e—
=3.782 D214112
Q in cfs, D and H in feet
Slope change occurs at weir -orifice transition
I /24/2005
5-49
2005 Surface Water Design Manual
•
APPENDIX C-4
CONVEYANCE FACILITIES DESIGN
(pending)
•
•
I�
U
APPENDIX D
MAINTENANCE REQUIREMENTS
FOR
PRIVATELY MAINTAINED DRAINAGE FACILITIES
17A
0
0 MAINTENANCE AND OPERATIONS MANUAL
FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES
ADDRESS: 122nd Avenue SE between SE 1881h Street and SE 192"d Street
Renton, Washington
RETENTIONIDETENTION FACILITIES
The purpose of the detention pond is to reduce the rate of runoff from the developed portions of
the property. Water can flow freely into the pond, but orifices in the outflow riser restrict the
outflow. When the inflow exceeds the capacity of the orifice, the excess water is "stored" in the
pond, and released slowly after the storm abates.
In order to function properly, the facility must also be kept free of accumulated sediment. The
outlet and connection pipes also must be kept clean, as even a partial blockage could
significantly impact the ability of the facility to store runoff. The facility should be visually
inspected for sediment accumulation and blockages at least once each year and also after
every major storm greater than or equal to a 10-year return frequency.
WATER QUALITY TREATMENT FACILITIES
The purpose of the permanently wet portions of the pond is to reduce the level of contaminants
in the runoff water, through sedimentation and filtration, though the plants in the wetpond will
also reduce pollutants though bic-uptake. It is essential that the water quality pond have calm
conditions and be inspected regularly for accumulation of sediment. The pond should be
18 visually inspected for sediment accumulation and blockages at least once each year and also
after every major storm greater than or equal to a I0-year return frequency_
CONVEYANCE SYSTEMS
Pipes transport runoff from one place to another, in this case from catch basins to the pond,
then to the downstream drainage system. To work properly, pipes must be kept free of silt and
other debris. If pipes become blocked, surface flooding will usually occur.
CATCH BASINS AND AREA DRAINS
Catch basins collect surface drainage and direct it into storm conveyance pipes. They help
prevent downstream drainage problems by trapping sediment and other debris that would
otherwise flow downstream with the runoff. It is important to keep catch basins clean so
accumulated silt is not flushed out during a significant storm. Also, if the outflow pipe becomes
blocked with debris, surface flooding will usually occur. All catch basins should be inspected at
least once each year and after major storms.
Area drains convey runoff directly into conveyance pipes. To prevent surface flooding, their
surface grates must be kept free of litter and debris. If dirt or other sediment gets into the pipes
and they become blocked, the pipes will need to be cleaned, either manually or using a Vactor
truck.
The following tables identify maintenance issues, which should be addressed regularly,
describing possible problems with the drainage system and their respective solutions.
0
Iis-
•
:7
•
APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 1 - DETENTION PONDS
Maintenance
Defect or Problem
Conditions When Maintenance Is Needed
Results Expected When
Component
Maintenance Is Performed
Site
Trash and debris
Any trash and debris which exceed t 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. !f trees are not a threat or
activities.
not interfering with access or maintenance, they
do not 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 t 0% 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.
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 inlet/outlet
No trash or debris In pipes.
pipes (includes floatables and non-floatables).
Damaged
Cracks wider than at the joint of the
No cracks more than'/ -inch wide at
inleUoutlef 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/Spillway
spillway.
Rock missing
Only one layer of rock exists above native soil in
Spillway restored to design
area five square feet or larger or any exposure of
standards.
native soil on the spillway.
1/9/2009
A-2
2009 Surface Water Design Manual —Appendix A
APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
11.5
•
•
•
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'!,
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 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,
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 Y: inch and longer than I foot
No cracks more than'4 inch wide at
at the joint of any inletloutlet pipe or any evidence
the joint of inletloutlei pipe.
of soil particles entering structure through cracks.
Settlementl
Structure has settled more than t 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 1/2-Inch at the joint of the
inletloutlet pipes or any evidence of soil entering
No cracks more than '!. -inch wide at
the joint of inletloutlet pipes.
the structure at the joint of the inletloutlet pipes.
Contaminants and
pollution
Any evidence of contaminants or pollution such
as oil, gasoline, concrete slurries or paint.
Materials removed and disposed of
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Ladder rungs missing
or unsafe
Ladder is unsafe due to missing rungs,
misalignment, rust, cracks, or sharp edges.
Ladder meets design standards and
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 ceanout gate,
2009 Surface Water Design Manual — Appendix A
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APPENDIX A MAINTENANCE. REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO.4 - CONTROL STRUCTUREIFLOW 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.
Chainlrod 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 place 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.
works as designed.
Overflow Pipe
Obstructions
Any trash or debris blocking (or having the
Pipe is free of all obstructions and
potential of blocking) the overflow pipe.
works as designed.
Deformed or damaged
Lip of overflow pipe is bent or deformed.
Overflow pipe does not allow
lip
overflow at an elevation lower than
design
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 f oatables and non-floatables).
Damaged
Cracks wider than Y3•inch at the joint of the
No cracks more than %-inch wide at
inlelYoutlet pipes or any evidence of soil entering
the joint of the Inletloutlet pipe.
at the joints of the inlet/outlet pipes.
Metal Grates
Unsafe grate opening
Grate with opening wider than'/a 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 CoverlLid
Coverllid not in place
Cover/lid 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. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Coverllid difficult to
One maintenance person cannot remove
Coverllid can be removed and
Remove
coverllid after applying 80 lbs. of lift.
reinstalled by one maintenance
person.
1/9/2009
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2009 Surface Water Design Manual — Appendix A
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO, 5 - CATCH BASINS AND MANHOLES
Maintenance
Defect or Problem
Condition When Maintenance Is Needed
Results Expected When
Component
Maintenance is Performed
Structure
Sediment
Sediment exceeds 6D% 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.
113 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
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 slab is free of holes and cracks.
cracks wider than Y. inch.
Frame not silting flush on top slab, i.e.,
Frame is sitting flush on top slab.
separation of more than 3/. inch of the frame from
the top slab.
Cracks in wails or
Cracks wider than A 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'!. inch wide at
at the joint of any in#etloutlet pipe or any evidence
the joint of inlet/outlet pipe.
of soil particles entering catch basin through
cracks.
Settlement/
Catch basin has settled more than 1 inch or has
Basin replaced or repaired to design
misalignment
rotated more than 2 inches out of alignment.
standards.
Damaged pipe joints
Cracks wider than at the joint of the
No cracks more than V/-inch wide at
inletloutlet pipes or any evidence of soil entering
the joint of inletloutlet pipes.
the catch basin at the joint of the inletloutlet
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 oil film.
InletlOutlet Pipe
Sediment
Sediment filling 20% or more of the pipe.
Inlet/outlet pipes Gear of sediment.
accumulation
Trash and debris
Trash and debris accumulated in inleiloutlet
No trash or debris in pipes.
pipes (includes floatables and non-floatables).
Damaged
Cracks wider than'/riach at the joint of the
No cracks more than'/. -inch wide at
inlettoutlet pipes or any evidence of soif entering
the joint of the inlet outlet pipe.
at the joints of the inlet/outlet pipes.
2009 Surface Water Design Manual — Appendix A
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 5 -- CATCH BASINS AND MANHOLES
Maintenance
Defect or Problem
Condition When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Metal Grates
Unsafe grate opening
Grate with opening wider than 716 inch.
Grate opening meets design
(Catch Basins)
standards.
Trash and debris
Trash and debris that is blocking more than 20%
Grate free of trash and debris.
of grate surface.
footnote to guidelines for disposal
Damaged or missing
Grate missing or broken member(s) of the grate,
Grate is in place and meets design
Any open structure requires urgent
standards.
maintenance.
Manhole Cover/Lid
Coverllid not in place
Coverllid is missing or only partially in place.
Coverllid 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. Baits
cannot be seated. Self-locking covarllid does not
work.
Coverllid difficult to
One maintenance person cannot remove
Coverllid can be removed and
Remove
cover/lid after applying 80 lbs. of lift.
reinstalled by one maintenance
person.
119/2009
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
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 flaws freely through pipes.
accumulation
20% of the diameter of the pipe.
Vegetation/roots
Vegetationtroots that reduce free movement of
Water flows freely through pipes.
water through 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 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 Geared from
square feet of ditch and slopes,
ditches.
Sediment
Accumulated sediment that exceeds 20% of the
Ditch cleanedlflushed of all sediment
accumulation
design depth.
and debris so that it matches design.
Noxious weeds
Any noxious or nuisance vegetation which may
Noxious and nuisance vegetation
constitute a hazard to County personnel or the
removed according to applicable
public.
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
Any evidence of contaminants or pollution such
Materials removed and disposed of
pollution
as oil, gasoline, concrete 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 Payer 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 Manual — Appendix A
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, 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
Structure
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 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.
1/9/2009
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2009 Surface Water Design Manual —Appendix A
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO.8 -- ENERGY DISSIPATERS
Maintenance
Defect or Problem
Conditions When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed.
Site
Trash and debris
Trash and/or debris accumulation.
Dissipater clear of trash andlor
debris
Contaminants and
Any evidence of contaminants or pollution such
Materials removed and disposed of
pollution
as ofl, gasoline, concrete slurries or paint.
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Rock Pad
Missing or moved
Only one layer of rock exists above native soil in
Rock pad prevents erosion.
Rock
area five square feet or larger or any exposure of
native soil.
Dispersion Trench
Pipe plugged with
Accumulated sediment that exceeds 20% of the
Pipe cleanedlflushed so that it
sediment
design depth.
matches design.
Not discharging water
Visual evidence of water discharging at
Water discharges from feature by
properly
concentrated points along trench (normal
sheet flow.
conditlon is a "sheet flow" of water along trench).
Perforations plugged.
Over 114 of perforations in pipe are plugged with
Perforations freely discharge flow,
debris or sediment.
Water flows out top of
Water flows out of distributor catch basin during
No flow discharges from distributor
"distributor" catch
any storm less than the design storm.
catch basin.
basin.
Receiving area over-
Water in receiving area is causing or has
No danger of landslides.
saturated
potential of causing landslide problems.
Gabions
Damaged mesh
Mesh of gabion broken, twisted or deformed so
Mesh is intact, no rock miss}ng,
structure Is weakened or rock may fall out.
Corrosion
Gabion mesh shows corrosion through more than
A11 gabion mesh capable of
% of its gage.
containing rock and retaining
designed form.
Collapsed or
Gabler basket shape deformed due to any
Ali gabion baskets intact, structure
deformed baskets
cause.
stands as designed.
Missing rock
Any rock missing that could cause gabion to
No rock missing.
loose structural integrity.
Manhole/Chamber
Worn or damaged
Structure dissipating flow deteriorates to % or
Structure fs in no danger of failing.
post, baffles or side of
original size or any concentrated worn spot
chamber
exceeding one square foot which would make
structure unsound.
Damage to wall.
Cracks wider than 1/2-inch or any evidence of soil
Manholelchamber is sealed and
frame, bottom, and/or
entering the structure through cracks, or
structurally sound.
top slab
maintenance inspection personnel determines
that the structure is not structurally sound.
Damaged pipe joints
Cracks wider than %-inch at the joint of the
No soil or water enters and no water
inletioutlet pipes or any evidence of soil entering
discharges at the joint of inlet/outlet
the structure at the joint of the inletloutlet pipes.
pipes.
2009 Surface Water Design Manual — Appendix A
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL., CONVEYANCE, AND WQ FACILITIES
NO.9 - FENCING
Maintenance
befect or Problem
Conditions When Maintenance Is Needed
Results Expected 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
IM. 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
unable 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 hoUng
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.
Openings in fabric
Openings in fabric are such that an 8-inch
Fabric mesh openings within 50% of
diameter ball could fit through. I
grid size.
1/9/2009
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 10 - GATES/BOLLARDSIACCESS BARRIERS
Maintenance
Defect or Problem
Conditions When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Chain Link Fencing
Damaged or missing
Missing gate.
Gates in place.
Gate
members
Broken or missing hinges such that gate cannot
Hinges intact and tubed. 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 t 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 lack gate
not link to ail 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 sire.
Bar Gate
Damaged or missing
Cross bar does not swing open or closed, is
Cross bar swings fulty 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
Ballard broken, missing, does not fit into support
No access for motorized vehicles to
hole or hinge broken or missing,
get into facility.
Does not lock
Locking assembly or lock missing or cannot be
No access for motorized vehicles to
attached to lock bollard in place.
get into facility.
Boulders
Dislodged
Boulders not located to prevent motorized vehicle
No access for motorized vehicles to
accessr
get into facility.
Circumvented
Motorized vehicles going around or between
No access for motorized vehicles to
boulders,
get into facility.
2009 Surface Water Design Manual — Appendix A
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 11 -GROUNDS (LANDSCAPING)
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 1,000 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.
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
broken which affect more than 25% of the total
Trees and shrubs with less than 5%
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 ieaning over, causing exposure
adequately supported; dead or
of the roots.
diseased trees removed.
t 1912009
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2009 Surface Water Design Manual — Appendix A
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 12 - ACCESS ROADS
Maintenance
Defect or Problem
Condition When Maintenance is Needed
Results Expected When
Component
Maintenance Is Performod
Site
Trash and debris
Trash and debris exceeds t 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 surfaoe 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 erasion 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
present other than a surface 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
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APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 16 - WETPOND
Maintenance
Defect or Problem
Condltion When Maintenance is Needed
Results Expected When
Component
Maintenance Is Performed
Site
Trash and debris
Any trash and debris accumulated on the
Wetpond site free of any trash or
wetpond site.
debris.
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/ground cover
Grass or groundcover exceeds 18 inches in
Grass or groundcover mowed to a
height.
height nc greater than 6 inches.
Side Slopes of Darn,
Rodent holes
Any evidence of rodent holes if facility is acting
Rodents removed or destroyed and
Berm, internal berm
as a dam or berm, or any evidence of water
dam or berm repaired.
or Embankment
plping through dam or berm via rodent holes.
Tree growth
Tree growth threatens integrity of dams, berms or
Trees do not hinder facility
slopes, does not allow maintenance access, or
performance or maintenance
interferes with maintenance activity. If trees are
activities.
not a threat to dam, berm or embankment
integrity, are not interfering with access or
maintenance or leaves do not cause a plugging
problem they do not 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.
Top or Side Slopes
Settlement
Any part of a dam, berm or embankment that has
Top or side slope restored to design
of Dam, Berm,
settled 4 inches lower than the design elevation.
dimensions. if settlement is
il berm or
significant, a licensed civil engineer
Embankment
should be consulted to determine
the cause of the settlement.
irregular surface on
Top of berm not uniform and level.
Top of berm graded to design
internal berm
elevation.
Pond Areas
Sediment
Accumulated sediment that exceeds 10% of the
Sediment cleaned out to designed
accumulation (except
designed pond depth.
pond shape and depth.
first wetpool cell)
Sediment
Sediment accumulations in pond bottom that
Sediment storage contains no
accumulation (first
exceeds the depth of sediment storage (1 foot)
sediment.
wetpoof cell)
plus 6 inches.
Liner damaged (if
Liner is visible or pond does not hold water as
Liner repaired or replaced.
Applicable)
designed
Water level (first
First cell empty, doesn't hold water.
Water retained in first cell for most of ,
wetpool cell)
the year.
Algae mats (first
Algae mats develop over more than 10% of the
Algae mats removed (usually in the
wetpool cell)
water surface should be removed.
late summer before Fall rains,
especially in Sensitive Lake
Protection Areas.)
Gravity Drain
Inoperable valve
Valve will not open and close.
Valve opens and closes normally.
Valve won't seal
Valve does not seal completely.
Valve completely seals closed.
Emergency Overflow
Tree growth
Tree growth impedes flow or threatens stability of
Trees removed.
Spillway
spillway.
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APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 16 - WETPOND
Maintenance
Defect or Problem
Condition When Maintenance Is Needed
Results Expected When
Component
Maintenance is YeHormad
Rock missing
Only one layer of rack exists above native soil in
Spillway restored to design
area five square feet or larger, or any exposure of
standards.
native soil at the top of out flow path of spillway.
Rip -rap on inside slopes need not be replaced.
InIetl00et Pipe
Sediment
Sediment filling 20% or more of the pipe.
Inlot/outlet pipes dear of sediment.
accumulation
Trash and debris
Trash and debris accumulated in inietloutlet
No trash or debris in pipes.
pipes (includes floatables and non-floatables).
Damaged
Cracks wider than' inch at the joint of the
No cracks more than V.-inch wide at
inletloutlet pipes or any evidence of soil entering
the joint of the inletloutlet pipe.
at the joints of the inlet/outlet pipes.
1 /9/2009
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2009 Surface Water Design Manual _ Appendix A
APPENDIX E
BOND QUANTITIES WORKSHEETS
(pending)
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APPENDIX F
RETENTION/DETENTION FACILITY
SUMMARY SHEET & SKETCH
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KING COUNT', WASHINGTON, SURFACF WATER DESIGN MANUAL
STORMWATER FACILITY SUMMARY SHEET DDES Permit
Number
(provide one Stormwater Facility Summary Sheet per Natural Discharge Location)
Overview:
cct Name
Downstream Drainage Basins
Major Basin Name Sba5
Immediate Basin Name f K
Flow Control:
Flow Control Facility Name/Number Co m6. Dck—r -A . f o-r d
Facility
Location S J5— Corr e!' 04
If none,
Flow control provided in regional/shared facility (give
location)
No flow control required Exemption number
General Facility Information:
Type/Number of detention facilities: Type/Number of infiltration facilities:
ponds ponds
vaults tanks
tanks trenches
Control Structure Location _I
Type of Control Structure N nI p ri Number of Orifices/Restrictions
Size of Orifice/Restriction:
No. 2
No. 3
No. 4
It
No. 1 2110
3,wu
Flow Control Performance Standard [',prl S .r,f
2009 Surface Water Design Manual 1/9/2009
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KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
Live Storage Volume �°j� (p2jDepth Volume Factor of Safety
Number of Acres Served 15.2-15
Number of Lots 3n
Dam Safety Regulations (Washington State Department of Ecology)
Reservoir Volume above natural grade _
Depth of Reservoir above natural grade
Facility Summary Sheet Sketch
All detention, infiltration and water quality facilities must include a detailed sketch.
01 "x 17" reduced size plan sheets may be used)
2009 Surface Water Design Manual
see raQ -any(xey"3 Ear,
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1 /9/2009
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KING COUNTY, WASHING -:'ON, SURFACE Y ATER DFSIGN MANUAL
Water Quality:
Type/Number of water quality facilities/BMPs:
biofiltration Swale
(regular/wet/ or continuous inflow)
large)
combined detention/wetpond
large)
(wetpond portio basic r large)
combined detention/wetvault
filter strip
flow dispersion
farm management plan
landscape management plan
oil/water separator
above
(baffle or coalescing plate)
Liner?
catch basin inserts:
Manufacturer
pre -settling pond
pre -settling structure:
Manufacturer
sand filter (basic or large)
sand filter, linear (basic or
sand filter vault (basic or
sand bed depth (inches)
stormwater wetland
storm filter
wetpond (basic or large)
wetvault
Is facility Lined?
If so, what marker is used
high flow bypass structure (e.g., flaw-splitter catch basin)
source controls
Design Information
Water Quality design flow
Water Quality treated volume (sandfilter)
Water Quality storage volume (wetpool)
0 Facility Summary Sheet Sketch
2009 Surface Water Design Manual
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1 /W2009
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KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
All detention, infiltration and water quality facilities must include a detailed sketch.
(11"xI7" reduced size plan sheets may be used) rr
— '�rtC� t n� .. S t� G��-C.a3 �+1 �Cc n � ! ✓l.� � �� ✓1 �1"
2009 Surface Water Design Manual 1/9/2009