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Phone 253.565.0552
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The Riley Group, Illc.
GEOTECHNICAL ENGINEERING REPORT
PREPARED By:
THE RILEY GROUP, INC.
17522 BOTHELL WAY NORTHEAST
BOTHELL, WASHINGTON 98011
PREPARED FOR:
McDoNALD'S USA, LLC
12131113TH AVENUE NORTHEAST, SUITE 103
KiRKLAND, WASHINGTON 98034
RGI PROJECT No. 2013-365
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GEOTECHNICAL ENGINEElUNG REpORT
BENSON McDONALD'S 46-1102
10660 SOUTHEAST 176TH STREET
RENTON,WASHINGTON
OCTOBER 25, 2013
SERVING THE PACIFIC NORTHWEST
Corporate Office
J 7522 Bothell Way Northeast
BofheJ/, Washington 98DII
Phone 425.4J5.0551 • Fax415.415.0311
wWlI',riley-group.com
Kellnewick, Washington
Phone 509.586.4840
Tfte Riley GI'OIlP, II/c.
October 25, 2013
Mr. Adam Brandenburg
McDonald's USA, LLC
12131 113th Avenue Northeast, Suite 103
Kirkland, Washington 98034
Subject: Geotechnical Engineering Report
Benson McDonald's 46-1102
10660 Southcllst 1761h Sh'eet
Renton, Washington
RGI Pl'Ojcct No. 2013-365
Dear Mr. Brandenburg:
As requested, The Riley Group, Inc. (RGI) has prepared this Geotec1mical Engineering
Rep0l1 (GER) for the above-referenced site. Our services were completed in accordance
with our proposal PRP2013·324 dated September 27, 2013 and authorized by McDonald's
USA, LLC on September 30, 2013. The information in this GER is based on our
understanding of the proposed construction, and the soil and groundwater conditions
encollntered in the borings completed by RGI at the site on October 13, 2013.
RGl recommends the project plans and specifications be submitted for a general review so
that RGI may confirm that the recommendations in this GER are interpreted and
implemented properly in the construction documents. RGI also recommends that a
representative of Ollr finn be present on site during portions of the project construction to
confirm that the soil and groundwater conditions are consistent with those that form the
basis for the engineering recommendations in this GER.
If you have any questions or require additional information, please contact us.
Respectfully submitted,
THE RILEY GROUP, INC.
Kristina M. Weller, PE
Senior Project Engineer
T(lcom(l, Washingtoll
Phone 253.565.0552
Ricky R. Wang, PhD, PE
Principal Engineer
SEnVING THE PACIFIC NORTIIWEST
Corpofllte Office
] 7522 Botheft Way NOl'lhr!m'J
Rothell. JJ'ash;IIgllJll 9801 J
Phone -125.415.0551 • Fax 425,4 J 5.0311
1I'II'U" l'iley-gl'Olfp. com
Kel/J/ewlck, Washing/ull
Phone 509.586.48-10
Geotechnical Engineering Report
Bensoll McDonald's 46-1102
ii
TABLE OF CONTENTS
October 25,2013
RGI Project No. 2013-365
EX C E C U TI V E S U MM A R Y """" , .. , ... " ....•........... ".,," .".,," "". "" ""." .,,",,""" """""" """"" ...... """.,, ... " .. ii i
1.0 I NTR 0 D U CTI 0 N """""""". "" .... ,,",," ".,," "." .. " ""."."" """.". "". " "" ".",,""" """" ,,""""" ."".,," I
2.0 P R OJ E CT DE SCR IPTI ON"" ",,",,"" "" """"""" """ """"",,"""""" """""".,," ".,,"" " ... """"" "" I
3.0 FIELD EXPLORATION AND LABORATORY TESTING """""""""""""".""""""""""""". I
3.1 FIELD EXPLORATION """ ......... " .... " .................. " ....... " ...................................................................... 1
3.2 LABORATORY TESTING ... " ................................................................................................................. 2
4.0 SITE CO ND IT IONS"" .. " ..... ,,"""" """". """ ... """".,, """.,," """" ... """" .. " ... "" ".". ". """" ... ,," "" 2
4.1 SURFACE ............................................................................................................................................ 2
4.2 GEOLOGY ....................................................... " .................................................................................. 2
4.3 SOILS .................................................................................................................................................. 2
4.4 GROUNDWATER ................................................................................................................ "" .............. 3
4.5 SEISMIC CONSIDERATIONS ................................................................................................................. 3
4.6 GEOLOGIC HAZARD AREAS ......................................................................... " ..................................... 4
5.0 D ISCUSSI ON AND R ECOMMENDA TlONS """"""""""".""""""""""""'''''''''''''''''''''''''''''''' 4
5.1 GEOTECHNICAL CONSIDERATIONS ........ "" ........................... " ............................................................ 4
5.2 EARTHWORK ...................................................................................................................................... 4
5.2.1 Erosion and Sediment Conlrol ..................................... " ............. " ............................................ 4
5.2.2 Stripping .................................................................................................................................... 5
5.2.3 Excavations ............................................................................................................................... 5
5.2.4 Site Preparation ......................................................................................................................... 6
5.2.5 Structural Fill ............................................................................................................................ 6
5.3 FOUNDATIONS ................................................................................................................................... 8
5.4 SLAB-ON-GRADE CONSTRUCTION ...................................................................................................... 8
5.5 DRAINAGE .......................................................................................................................................... 9
5.5.1 Surface ...................................................................................................................................... 9
5.5.2 Subsurface ................................................................................................................................. 9
5.6 UTILITIES ............................................................................................................................................ 9
5.7 PAVEMENTS ........................................................................................................................................ 9
6.0 ADD ITI 0 NA L SERVICES """"" ... "",,,.,,.,,,,,,,,,,.,,,,,,,,,,.,, .. ,,,,,, ... ,,,, .. ,,,,.,,,, .. ,,.,,.,,,,,, .. """."."."". 10
7.0 LIM ITA T IONS "".""" .. """"""""""""""""""""""."""."""" .. "".""""""""""""" .. "" .. """,,.,," 10
LIST OF APPENDICES
Figure 1 ................................................................................................................... Site Vicinity Map
Figure 2 ............................................................................................. Geotechnical Exploration Plan
Figure 3 ................................................................................................ Typical Footing Drain Detail
Appendix A ........................................................................ Field Exploration and Laboratory Testing
THE RILEY GROUP, INC.
Geotechnical Engineering Report
Benson McDonald's 46-1102
Executive Summary
iii October 25,20/3
RGI Project No. 2013-365
This Executive Summary should be used in conjunction with the entire GER for design
and/or construction purposes. It should be recognized that specific details were not
included or fully developed in this section, and this GER must be read in its entirety for a
comprehensive understanding of the items contained herein. Section 7.0 should be read for
an understanding of limitations.
RGl's geotechnical scope of work included the advancement of six borings to depths up to
20.5 feet below ground surface (bgs).
Based on the information obtained from our subsurface exploration, the site is suitable for
development of the proposed project. The following geotechnical considerations were
identified.
Soil Conditions: The soils encountered during our field exploration include up to 15 feet
of loose to medium dense fill comprised of silty sand with varying amounts of gravel over
native soil. The native soil is glacial till consisting of medium dense to very dense silty
sand with gravel.
Groundwater: Groundwater seepage was not encountered during our field exploration at
depths of 10.5 to 20.5 feet bgs.
Foundations: Foundations for the proposed building can be supported on conventional
continuous and spread footings bearing on 12 inches of structural fill or competent native
soils.
Slab-on-grade: Slab-on-grade floors for the proposed building can be supported on 12
inches of structural fill or competent native soils.
Pavements: The following pavement sections are recommended:
~ For heavy truck traffic areas: 3 inches of asphalt concrete (AC) over 6 inches of
crushed rock base (CRB)
~ For general parking areas: 2 inches of AC over 4 inches of CRB
~ For drive-thru areas: 5 inches of concrete over 4 inches of CRB
THE RILEY GROUP, INC.
Geotechnical Fngineering Report
Benson AlcDonald's 46-1102
1.0 Introduction
Pnge} October 25, 2013
RGI Project No. 2013-365
This Geotechnical Engineering Report (GER) presents the results of the geotechnical
engineering services provided for the proposed Benson McDonald's 46-1102 in Renton,
Washington. The purpose of this GER is to assess subsurface conditions and provide
geotechnical recommendations for the construction of a new McDonald's restaurant. Our
scope of services included field explorations, laboratory testing, engineering analyses, and
preparation of this GER.
The recommendations in the following sections of this GER are based upon our current
understanding of the proposed site development as outlined below. If actual features vary
or changes are made, RGI should review them in order to modify our recommendations as
required. In addition, RGI requests to review the site grading plan, final design drawings
and specifications when available to verify that our project understanding is correct and
that our recommendations have been properly interpreted and incorporated into the project
design and construction.
2.0 Project description
The site is located at 10660 Southeast 176th Street in Renton, Washington. The
approximate location of the site is shown on Figure I. The site is currently within the
Valley Hill Plaza, which will be redeveloped soon.
RGI understands that a new, a 4,104-square-foot McDonald's building and associated
drive aisles and drive-thru will be constructed in the northern portion of the site. The
remainder of the site will be developed with a retail building and asphalt parking.
At the time of preparing this GER, detailed site grading and building plans were not
available for our review. Based on our experience with similar construction, RGI
anticipates that the proposed building will be supported on perimeter walls with bearing
loads of I to 2 kips per linear foot, and a series of columns with a maximum load up to 50
kips. Slab-on-grade floor loading of 250 pounds per square foot (pst) are expected. RGI
also expects that no major grading will be needed to reach the final grade.
3.0 Field Exploration and Laboratory Testing
3.1 FIELD EXPLORATION
On October 13, 2013, RGI observed the drilling of six borings. Borings B-2 and B-3 were
drilled in the area close the proposed McDonald's building footprint. Borings B-1, B-5,
and B-6 were drilled in the proposed driveway and parking area. Boring B-4 was drilled in
the proposed monument sign area. Due the existing building and utilities, all borings are
drilled as close as possible as the locations proposed in our proposal. One boring was
eliminated due to conflict with utilities. The approximate exploration locations are shown
on Figure 2.
Field logs of each exploration were prepared by the project geologist who continuously
observed the drilling. These logs included visual classifications of the materials
encountered during drilling as well as our interpretation of the subsurface conditions
THE RILEY GROUP, INC.
Geotechnical Engineering Report
Benson McDonald's 46-1102
Page 2 October 25, 2013
RGJ Project No. 2013-365
between samples, The boring logs included in Appendix A represent an interpretation of
the field logs and include modifications· based on laboratory observation and analysis of
the samples.
3.2 LABORATORY TESTING
During the field investigation, a representative portion of each recovered sample was
sealed in containers and transported to our laboratory for further visual and laboratory
examination, Samples retrieved from the borings were tested for moisture content to aid in
soil classification and provide input for the recommendations provided in this GER, The
results and descriptions of the laboratory tests are enclosed in Appendix A.
4.0 Site Conditions
4.1 SURFACE
The site is a trapezoidal-shaped parcel of land approximately three acres in size, The site is
bound to the north by Southeast 174th Street, to the east by 108th Avenue Southeast, to the
south by the proposed retail building and parking and Southeast 176th Street, and to the
west by commercial properties.
The site is occupied by the former Valley Hill Plaza building in the western portion of the
sit and paved parking area across the remainder, The existing building will be demolished
to make way for the currently proposed redevelopment of the site,
4.2 GEOLOGY
Review of the Geologic Map of King County Washington. by Derek B. Booth, et al (2002)
indicates that the soil in the project vicinity consists of till (Map Unit Qvt), which is a
compact mixture of sand, silt, and gravel deposited by glacial ice, Thicknesses can range
trom several meters to a few tens of meters, The descriptions are similar to the native soils
encountered in our field exploration,
4.3 SOILS
The soils encountered during our field exploration include up to 15 feet ofloose to medium
dense fill comprised of silty sand with varying amounts of gravel over native soil in the
western portion of the site, The native soil is glacial till consisting of medium dense to very
dense silty sand with gravel. Fill was not encountered in the eastern portion of the site, The
fill appears to have been placed during the construction of the existing development.
More detailed descriptions of the subsurface conditions encountered are presented in the
borings are included in Appendix A, Sieve analysis was performed on two selected soil
samples, Grain-size distribution curves are included in Appendix A,
THE RILEY GROUP, INC.
Genrechnica.! Engineering Report
Iienson McDonald's 46-1102
4.4 GROUNDWATER
Poge 3 Oclober 25.2013
RGI Project No. 2013-365
Slight groundwater seepage was encountered in boring B-3 during our subsurface
exploration. We do not expect significant groundwater will be encountered if the
construction occurs during the dry season (June through September) but the contractor
should be prepared for seepage in utility excavations.
It should be recognized that fluctuations of the groundwater table will occur due to
seasonal variations in the amount of rainfall, runoff, and other factors not evident at the
time the explorations were performed. In addition, perched water can develop within seams
and layers contained in fill soils or higher permeability soils overlying less permeable soils
following periods of heavy or prolonged precipitation.
4.5 SEISMIC CONSIDERATIONS
Based on the 2009 International Building Code (IBC), RGI recommends the following
seismic parameters for design:
2009 mc Parameter
Site Soil Class'
Site Latitude
Site Longitude
Short Period Spectral Response Acceleration, S, (percent g)
I-Second Period Spectral Response Acceleration, S, (percent g)
Seismic Coefficient, FA
Seismic Coefficient, Fv
Value
D'
47.4450349 N
122.1994162 W
1.382
0.472
1.00
1.528
I. Note: In general accordance with the 2009 me Table 1613.5.2. !Be Site Class is based on the average characteristics of the upper 100
feet of the subsurface profite.
2. Note: The 2009 me requires a sile soil profile determination extending to a depth of 100 feet for seismic site classification. The
current scope of our services does not include the required 100-foot soil profile determination. Borings extended to a maximum depth of
20.5 feet, and this seismic site class definition considers that similar soil continues below the maximum depth of the subsurface
exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of
exploration.
Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength
due to an increase in water pressure induced by vibrations from a seismic event.
Liquefaction mainly affects geologically recent deposits of fine-grained sands that are
below the groundwater table. Soils of this nature derive their strength from intergranular
friction. The generated water pressure or pore pressure essentially separates the soil grains
and eliminates this intergranular friction, thus reducing or eliminating the soil's strength.
RGI reviewed the soil conditions encountered during field exploration and assessed the
potential for liquefaction of the site's soil during an earthquake. The native soil is glacial
till; in our professional opinion the potential of soil liquefaction during an earthquake event
is minimal.
THE RILEY GROUP, INC.
Geotechnical Engineering Report
Benson McDonald's 46~/102
4.6 GEOLOGIC HAZARD AREAS
Page 4 October 25,2013
RGI Project No. 2013-365
Regulated geologically hazardous areas include erosion, landslide, earthquake, or other
geological hazards. Based on the conditions observed on the site, the site does not contain
geologically hazardous areas.
5.0 Discussion and Recommendations
5.1 GEOTECHNICAL CONSIDERATIONS
Based on our study, the site is suitable for the proposed construction from a geotechnical
standpoint. The proposed building area will be underlain by existing fill in the western
portion and by native soil in the eastern portion. To avoid potential differential settlement,
RGI recommends that foundations for the proposed building be supported on conventional
spread footings bearing on 12 inches of structural fill or competent native granular soils.
Slab-on-grade floors should also be supported on 12 inches of structural fill or competent
native soil. The pavement section can be supported on the existing fill or native soil after
proof-rolling. Moisture conditioning and compaction of the native soils and existing fill
should be expected.
Detailed recommendations regarding the above issues and other geotechnical design
considerations are provided in the following sections. These recommendations should be
incorporated into the final design drawings and construction specifications.
5.2 EARTHWORK
RGI expects that site grading will consist of shallow cuts and fills to achieve building and
pavement grades and excavation for utilities including storm, water, sanitary sewer, and
other utilities. Due to the moisture sensitive nature of the shallow soils, RGI recommends
earthwork take place in the dryer summer months.
5.2.1 EROSION AND SEDIMENT CONTROL
Potential sources or causes of erosion and sedimentation depend on construction methods,
slope length and gradient, amount of soil exposed and/or disturbed, soil type, construction
sequencing and weather. The impacts on erosion-prone areas can be reduced by
implementing an erosion and sedimentation control plan. The plan should be designed in
accordance with applicable city and/or county standards.
RGI recommends the following erosion control Best Management Practices (BMPs):
~ Scheduling site preparation and grading for the drier summer and early fall months
and undertaking activities that expose soil during periods oflittle or no rainfall
~ Retaining existing vegetation whenever feasible
~ Establishing a quarry spall construction entrance
~ Installing siltation control fencing or anchored straw or coir wattles on the downhill
side of work areas
~ Covering soil stockpiles with anchored plastic sheeting
THE RILEY GROUP, INC.
Geotechnical Engineering Report
Benso/l McDonald's 46-1102
Poge 5 October 25,2013
RGJ Project No. 2013-365
>-Revegetating or mulching exposed soils with a minimum 3-inch thickness of straw
if surfaces will be left undisturbed for more than one day during wet weather or one
week in dry weather
>-Directing runoff away from exposed soils and slopes
:;;. Minimizing the length and steepness of slopes with exposed soils and cover
excavation surfaces with anchored plastic sheeting (Graded and disturbed slopes
should be tracked in place with the equipment running perpendicular to the slope
contours, so that the track marks provide a texture to help resist erosion and
channeling. Some sloughing and raveling of slopes with exposed or disturbed soil
should be expected.)
:;;. Decreasing runoff velocities with check dams, straw bales or coir wattles
:;;. Confining sediment to the project site
:;;. Inspecting and maintaining erosion and sediment control measures frequently (The
contractor should be aware that inspection and maintenance of erosion control
BMPs is critical toward their satisfactory performance. Repair and/or replacement
of dysfunctional erosion control elements should be anticipated.)
Permanent erosion protection should be provided by reestablishing vegetation using
hydro seeding and/or landscape planting. Until the permanent erosion protection is
established, site monitoring should be performed by qualified personnel to evaluate the
effectiveness of the erosion control measures. Provisions for modifications to the erosion
control system based on monitoring observations should be included in the erosion and
sedimentation control plan.
5.2.2 STRIPPING
Stripping should include removal of the existing foundations and pavements. The borings
encountered 2 to 5 inches of asphalt concrete paving underlain by crushed rock base.
5.2.3 EXCAVATIONS
All temporary cut slopes associated with the site and utility excavations should be
adequately inclined to prevent sloughing and collapse. The site soils consisted of fill soils
underlain by medium dense to very dense silty sand.
Accordingly, for excavations more than 4 feet but less than 20 feet in depth, the temporary
side slopes should be laid back with a minimum slope inclination of 1.5H: I V
(Horizontal:Vertical). If there is insufficient room to complete the excavations in this
manner, or excavations greater than 20 feet in depth are planned, using temporary shoring
to support the excavations should be considered. For open cuts at the site, RGI
recommends
:;;. No traffic, construction equipment, stockpiles or building supplies are allowed at
the top of cut slopes within a distance of at least 5 feet from the top of the cut.
:;;. Exposed soil along the slope is protected from surface erosion using waterproof
tarps and/or plastic sheeting.
:;;. Construction activities are scheduled so that the length of time the temporary cut is
left open is minimized.
THE RILEY GROUP, INC.
Geotrchl1lca/ F-ngilleering Report
Benson McDonald's 46-1 J02
Page 6
> Surface water is diverted away from the excavation.
October 25,20/3
RGI Project No. 2013-365
> The general condition of slopes should be observed periodically by a geotechnical
engineer to confirm adequate stability and erosion control measures.
In all cases, however, appropriate inclinations will depend on the actual soil and
groundwater conditions encountered during earthwork. Ultimately, the site contractor must
be responsible for maintaining safe excavation slopes that comply with applicable OSHA
or WISHA guidelines.
5.2.4 SITE PREPARATION
RGI anticipates that some areas of loose or soft soil will be present on the site after
stripping operations are complete. Proof rolling and subgrade verification should be
considered an essential step in site preparation. Prior to placement of structural fill, RGI
recommends proofrolling building and pavement subgrades and areas to receive structural
fill. These areas should be proof rolled under the observation of RGI and compacted to a
firm and unyielding condition in order to achieve a minimum compaction level of 95
percent of the modified proctor maximum dry density as determined by the American
Society of Testing and Materials Dl557-09 Standard Test Methods for Laboratory
Compaction Characteristics of Soil Using Modified Effort (ASTM DI557).
Proofrolling and adequate subgrade compaction can only be achieved when the soils are
within approximately ± 2 percent moisture content of the optimum moisture content. Soils
may be proofrolled with a heavy compactor, loaded double-axle dump truck, or other
heavy equipment under the observation of a RGI representative. This observer will assess
the subgrade conditions prior to filling. The need for or advisability of proof rolling due to
soil moisture conditions should be determined at the time of construction. In wet areas it
may be necessary to hand probe the exposed subgrades in lieu of proofrolling with
mechanical equipment.
Subgrade soils that become disturbed due to elevated moisture conditions should be
overexcavated to reveal firm, non-yielding, non-organic soils and backfilled with
compacted structural fill. In order to maximize utilization of site soils as structural fill, RGI
recommends that the earthwork portion of this project be completed during extended
periods of warm and dry weather, if possible. If earthwork is completed during the wet
season (typically November through May) it will be necessary to take extra precautionary
measures to protect subgrade soils. Wet season earthwork will require additional mitigative
measures beyond what would be expected during the drier summer and fall months.
5.2.5 STRUCTURAL FILL
Once site preparation is complete, cuts and fills can be made to establish desired building
grades. Prior to placing fill, RGI recommends proof-rolling as described above.
RGI recommends fill below the foundation and floor slab, behind retaining walls, and
below pavement and hardscape surfaces be placed in accordance with the following
recommendations for structural fill. The structural fill should be placed after completion of
site preparation procedures as described in Section 5.2.4.
The suitability of excavated site soils and import soils for compacted structural fill use will
depend on the gradation and moisture content of the soil when it is placed. As the amount
THE RILEY GROUP, INC.
Georechnical Engineering Report
Benson McDonald's 46-1102
Page 7 October 25,2013
RGI Project No. 2013-365
of fines (that portion passing the U,S, No. 200 sieve) increases, soil becomes increasingly
sensitive to small changes in moisture content and adequate compaction becomes more
difficult or impossible to achieve, Soils containing more than about 5 percent fines cannot
be consistently compacted to a dense, non-yielding condition when the moisture content is
more than 2 percent above or below optimum. Optimum moisture content is the moisture
that results in the greatest compacted dry density with a specified compactive effort.
Excavated site soil contains a large percentage of silt and may not be suitable for re-use as
structural fill. It may be necessary to import clean, granular soils to complete site work that
meets the grading requirements listed in Table 1 or the 2010 Washington State Department
of Transportation (WSDOT) Standard Specifications for Road, Bridge, and Municipal
Construction, Section 9-03.9(3),
Table 1 Structural Fill Gradation
U.S. Sieve Size Percent Passing
3 inches 100
% inch 70 minimum
No.4 35 to 60
No, 200 o to S*
"'Based on minus 3/4 inch fraction.
Prior to use, a RGI representative should observe and test all materials imported to the site
for use as structural fill. Structural fill materials should be placed in uniform loose layers
not exceeding 12 inches and compacted as specified in Table 2. The soil's maximum
density and optimum moisture should be determined by ASTM D1557.
Location
Table 2 Structural Fill Compaction ASTM D1557
Material Type
Minimum
Compaction
Percentage
Moisture Content
Range
Foundations IOn-site granular or approved 95 +2 -2
. . . . . ... . . . . . . . ...... .....jhnportedfillsoils..! ................................... ········· .... · .. · .... _·1_········· .. ··· .... ·········· .... · .. ·· i··· ........... .
Retaining Wall Backfill
Slab-on-grade
I
' On-site granular or approved
importedfill soils .
[
. on-.site. g.r .. a.nul.ar or approved
imported fill soils
92
95
+2 -2
+2 -2
General Fill (non-lOn-site granular or approved I 90 +3 -2 structL,ral areas)... ..._...._importedJills()is._ .... ____ ...... _. ...... . ............ _____ .+_ .. _._._._ -I-___ .. _._. __ .. _
~:::'~~~~;s~Ubgradean~J;~~;:r;~u:;il~rapproved 95 +2 -2
Placement and compaction of structural fill should be observed by RGI. A representative
number of in-place density tests should be performed as the fill is being placed to confirm
that the recommended level of compaction is achieved.
THE RILEY GROUP, INC.
Geotechnical Engineering Report
Benson McDonald's 46-1102
5.3 FOUNnA TIONS
Page 8 October 25.2013
RGI Project No. 2013-365
Following site preparation and grading, the proposed building foundation can be supported
on conventional spread footings bearing on 12 inches of structural fill or competent native
soils. Where loose existing fill soils or other unsuitable soils are encountered in the
proposed building footprint, they should be overexcavated at least 1 foot and backfilled
with structural fill. Additional overexcavations may be necessary depending on the
condition of the existing fill soils during construction.
Perimeter foundations exposed to weather should be at a minimum depth of 18 inches
below final exterior grades. Interior foundations can be constructed at any convenient
depth below the floor slab. Finished grade is defined as the lowest adjacent grade within 5
feet of the foundation for perimeter (or exterior) footings and finished floor level for
interior footings.
Table 3 Foundation nesign
Desigu Parameter
Allowable Bearing Capacity
Friction Coefficient
Passive pressure (equivalent fluid pressure)
1 psf = pounds per square foot
2 pef= pounds per cubic foot
Minimum foundation dimensions
Value
2,500 psI"
0.25
250 pcf
Columns: 24 inches
Walls: 16 inches
The allowable foundation bearing pressures apply to dead loads plus design live load
conditions. For short-term loads, such aswind and seismic, a 1/3 increase in this allowable
capacity may be used. At perimeter locations, RGI recommends not including the upper 12
inches of soil in the computation of passive pressures because it can be affected by weather
or disturbed by future grading activity. The passive pressure value assumes the foundation
will be constructed neat against competent soil or backfilled with structural fill as
described in Section 5.2.5. The recommended base friction and passive resistance value
includes a safety factor of about 1.5.
With spread footing foundations designed in accordance with the recommendations in this
section, maximum total and differential post-construction settlements of 1 inch and 112
inch, respectively, should be expected.
5.4 SLAB-aN-GRADE CONSTRUCTION
Once site preparation has been completed as described in Section 5.2, suitable support for
slab-on-grade construction should be provided. ROI recommends that the concrete slab be
placed on top of 12 inches of structural fill or on competent native soils. It may be possible
to moisture condition and compact the existing fill soils to the requirements of structural
fill.
Immediately below the floor slab, RGI recommends placing a 4-inch-thick capillary break
layer of clean, free-draining pea gravel, washed rock, or crushed rock that has less than 5
THE RILEY GROUP, INC.
Geotechnical Engineering Report
Benson McDonald's 46-J J 02
Page 9 October 25. 2013
RGI Project No. 2013-365
percent passing the U.S. No. 200 sieve. This material will reduce the potential for upward
capillary movement of water through the underlying soil and subsequent wetting of the
floor slab. Where moisture by vapor transmission is undesirable, an 8-to 10-millimeter-
thick plastic membrane should be placed on a 4-inch-thick layer of clean gravel or rock.
For the anticipated floor slab loading, we estimate post-construction floor settlements of
Yi-to V,-inch. For thickness design of the slab subjected to point loading from storage
racks, RGI recommends using a subgrade modulus (Ks) of 150 pounds per square inch per
inch of deflection.
5.5 DRAINAGE
5.5.1 SURFACE
Final exterior grades should promote free and positive drainage away from the building
area. Water must not be allowed to pond or collect adjacent to foundations or within the
immediate building area. For non-pavement locations, RGI recommends providing a
minimum drainage gradient of 3 percent for a minimum distance of 10 feet from the
building perimeter. In paved locations, a minimum gradient of I percent should be
provided unless provisions are included for collection and disposal of surface water
adjacent to the structure.
S.S.2 SUBSURFACE
RGI recommends installing perimeter foundation drains, details shown on Figure 3. The
foundation drains and roof downspouts should be tightlined separately to an approved
discharge facility. Subsurface drains must be laid with a gradient sufficient to promote
positive flow to a controlled point of approved discharge.
5.6 UTILITIES
Utility pipes should be bedded and backfilled in accordance with American Public Works
Association (APWA) specifications. For site utilities located within the right-of-ways,
bedding and backfill should be completed in accordance with City of Renton
specifications. At a minimum, trench backfill should be placed and compacted as structural
fill, as described in Section 5.2.5. Where utilities occur below unimproved areas, the
degree of compaction can be reduced to a minimum of 90 percent of the soil's maximum
density as determined by ASTM D1557. As noted, onsite excavated soils containing a
large percentage of silt and may not be suitable for use as backfill. Imported structural fill
may be required for trench backfill.
5.7 PAVEMENTS
Pavement subgrades should be prepared as described in Section 5.2 of this GER and as
discussed below. Regardless of the relative compaction achieved, the subgrade must be
firm and relatively unyielding before paving. This condition should be verified by
proofrolling with heavy construction equipment or hand probe by inspector.
With the pavement subgrade prepared as described above, RGI recommends the following
pavement sections for parking and drive areas paved with flexible asphalt concrete
surfacing.
THE RILEY GROUP, INC.
Geotechnical Engineering Report
Hellson McDonald's ./6-1102
Po!!e /0 October 25, 20/3
RGI Project No. 20/3-365
>-For heavy truck traffic areas: 3 inches of asphalt concrete (AC) over 6 inches of
crushed rock base (CRB)
>-For general parking areas: 2 inches of AC over 4 inches of CRE
The asphalt paving materials used should conform to the Washington State Department of
Transportation (WSDOT) specifications for Hot Mix Asphalt Class 112 inch and CRE
surfacing,
> For drive-thru areas: 5 inches of concrete over 4 inches of CRE
Long-term pavement performance will depend on surface drainage. A poorly-drained
pavement section will be subject to premature failure as a result of surface water
infiltrating into the subgrade soils and reducing their supporting capability,
For optimum pavement performance, surface drainage gradients of no less than two
percent are recommended, Also, some degree of longitudinal and transverse cracking of
the pavement surface should be expected over time, Regular maintenance should be
planned to seal cracks when they occur.
6.0 Additional Services
RGI is available to provide further geotechnical consultation throughout the design phase
of the project. We should review the final design and specifications in order to verify that
earthwork and foundation recommendations have been properly interpreted and
incorporated into project design and construction,
RGI is also available to provide geotechnical engineering and construction monitoring
services during construction, The integrity of the earthwork and construction depends on
proper site preparation and procedures, In addition, engineering decisions may arise in the
lield in the event that variations in subsurface conditions become apparent. Construction
monitoring services are not part of this scope of work, If these services are desired, please
let us know and we will prepare a proposal.
7.0 Limitations
This GER is the property of RGI, McDonald's USA, LLC, and their designated agents,
Within the limits of the scope and budget, this GER was prepared in accordance with
generally accepted geotechnical engineering practices in the area at the time this report was
issued. This GER is intended for specific application to the Proposed Benson McDonald's
46-1102 project at 10660 Southeast 176th Street in Renton, Washington, and for the
exclusive use of McDonald's USA, LLC and its authorized representatives, No other
warranty, expressed or implied, is made. Site safety, excavation support, and dewatering
requirements are the responsibility of others,
The scope of services for this project does not include either specifically or by implication
any environmental or biological (for example, mold, fungi, bacteria) assessment of the site
or identification or prevention of pollutants, hazardous materials, or conditions, If the
owner is concerned about the potential for such contamination ot pollution, we can provide
a proposal for these services.
THE RILEY GROUP, INC.
Geotechnical Engineering Report
Benson McDonald's 46-I I 02
Page II October 25. 2013
RGI Prqject No. 2013-365
The analyses and recommendations presented in this GER are based upon data obtained
from the test exploration performed on site. Variations in soil conditions can occur, the
nature and extent of which may not become evident until construction. If variations appear
evident, RGI should be requested to reevaluate the recommendations in this GER prior to
proceeding with construction.
It is McDonald's USA, LLC's responsibility to see that all parties to the project, including
the designers, contractors, subcontractors, are made aware of this GER in its entirety. The
use of information contained in this GER for bidding purposes should be done at the
contractor's option and risk.
THE RILEY GROUP, INC.
USGS, 1994, Renton, Washington
7.5-Minute Quadrangle
The Riley Group, Inc.
17522 Bothell Way Northeast
Rothell, Washington 98011
Phone: 425.415.0551 • Fax: 425.415.0311
Approximate Scale: I ''~1000'
i o 500 1000
Benson McDonald's 46-1102
RGJ Project Number
2000
Figure I
Date Drawn: Site Vicinity Map
2013-365 1012013
Address: 10660 Southeast 176th Street, Renton, Washington 98055
L
'~ .. ~ .... ~. 1
I Plt~~~~E I 90~ sr
--"-
-", /-' . ,. J .,,-·i \/ ~ ,J\ I ,-'.
9 ~ I~'
I
\ \ Vg' II IV fill \
MdJOt~ALn'S R[ST,.6,Ur~i\tH
,E!,37+5R
'1,10·!-SF
•
"
/ ,
I/" I
i I'~
lr--~~
~ ... ...
\. PflOPOSf[) PR(WP.!Y LI'-I~ ...
,f!t.--"',
~ = B-1 to B-3, IS' bgs
B-4, 20' bgs
B-5 to 8-6, 10' bgs
Drawn from Core States, Preliminary Site Plan, C2, 09/10/13,
,-EXISflNI; RICH r -IN
/ RI("',H[-OlJl
\1(1
4,~
I"
\ j "~~
IV
II " ~6 \ T'
1"1' ~ ~ ~
',;! . meIRiCAL. -
lRANSF"[l/\'MER
P"~
PROPOSED
RETAIL
16,273 sf
1.67 Ac,
l!l;EO: C{)jIJ£Ra~L ARTERIAL (C.l.j
PARKING REOUIRfD·. 32
PARKING PROVIDED, 69
Approximate Scale: 1 "=50'
I o 25 50 100
A
N
Benson McDonald's 46-1102 Figure 2 The Riley Group, Inc.
17522 Bothell Way Northeast
Bothell, Washington 98011
ROf Project Number
2013-365
Geotechnical Exploration Plan Date Drawn:
1012013
Phone 425.415.0551 • Fax: 425.415.0311 Address: 10660 Southeast 176th Street, Renton, Washington 98055
Building Slab
• .• •
, '/ / • >-; 4
/ • >-;
/, /,
•
•
/,
4 •.
4 .'~ .. ~.~ .. ~.~. ~~~~~~~~~~~~~0'~/.7~~'/~
.,
•
•
• .... ..
•
.. .....
•
. 4 ...
• 4.
..
" .
/,
';:, "
Filter Fabric
4" Perforated Pipe
3/4" Washed Rock or Pea Gravel
Not to Scale
The Riley Group, Inc. Benson McDonald's 46-1102
RGI Project Number
Figure 3
Date Drawn:
10/2013
17522llothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551 • Fax: 425.415.0311
2013-365
Typical Footing Drain Detail
Address: 10660 Southeast 176th Street, Renton, Washington 98055
Geotechnical Engineering Report
Benson McDonald 's 46~' 102
APPENDIX A
Gerober 25, 2013
RGI Project No. 2013-365
FIELD EXPLORATION AND LABORATORY TESTING
On October 13, 2013, RGI performed field explorations using a track-mounted drill rig,
RGI explored subsurface soil conditions at the site by observing the drilling of six borings
to a maximum depth of 20,5 feet below existing grade, The boring locations were
approximately determined by measurements from existing property lines and paved roads,
A geologist from our office conducted the field exploration and classified the soil
conditions encountered, maintained a log of each test exploration, obtained representative
soil samples, and observed pertinent site features, All soil samples were visually classified
in accordance with the Unified Soil Classification System (USCS),
Representative soil samples obtained from the explorations were placed in closed
containers and taken to our laboratory for further examination and testing, As a part of the
laboratory testing program, the soil samples were classified in our in house laboratory
based on visual observation, texture, plasticity, and the limited laboratory testing described
below.
Moisture Content Determinations
Moisture content determinations were performed in accordance with the American Society
for Testing and Materials ASTM D2216-10 Standard Test Methods for Laboratory
Determination of Water (Moisture) Content of Soil and Rock by Mass (ASTM D2216) on
representative samples obtained from the exploration in order to aid in identification and
correlation of soil types, The moisture content of typical sample was measured and is
reported on the boring logs,
Grain-size analysis
A grain-size analysis indicates the range in diameter of soil particles included in a
particular sample, Grain-size analyses for the greater than 75 micrometer portion of the
samples were performed in accordance with ASTM D422 Standard Test Method for
Particle-Size Analysis of Soils (ASTM D422) on two of the samples,
THE RILEY GROUP, INC.
Project Name: Benson McDonald's 46-1102 ~ Boring No.: B-1
Project Number: 2013-365 Sheet 1 of 1
Client: McDonald's USA, LLC
Date(s) Drilled: 10113/2013 logged By: ELW Surface Conditions: Asphalt
Drilling Method(s): Hollow Stem Auger Drill Sil Size(fype: 6" Total Depth of Borehole: 16.5 feet bgs
Drill Rig Type: Trailer-Mounted Drilling Contractor: Boretee Approximate N/A
Surface Elevation:
Groundwater Level N t t d
and Dale Measured: 0 encoun ere Sampling Method(s): SPT H D I 140 Ib, 30" drop, rope and
ammer a a: cathead
Borehole Backfill: Bentonite Chips Location: 10660 Southeast 176th Street, Renton, Washington
oi u c
'63 ~
I~ .~ '0
~ '63 $ ~ .c Ii 9 OC E ~ c ~ '" ~ >-
0 1 $ £;1:: $ if) ~ ~ .c 0. at/) ~ if) il
> Ci. E E ~ u () ~
ID " ro ro 0 $ if) MATERIAL DESCRIPTION '0
[jj 0 if) (/):5 oc :0 :2
-,"3-.,phalt ave, c,"shed
~;~:; silty 110 silly g,avelty SAND. medl"m dense. molsl
s: :::; ,. 7.0
-5-s: organics -
:::; 13 14.7
-10-§ r--
11 -10.0
-
-
-15-s: [±:IIIYSAND with some grave;: m8dlumdense. mOls1(GlaclalnU)----
:s 23 9.1
. Boring I I aI16.5·
-20---
-25-r--
--
-
-
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 96011
Project Name: Benson McDonald's 46-1102 I~ Boring No.: B-2 Project Number: 2013-365 . Sheet 1 of 1
Client: McDonald's USA, LLC
Oate(s} Drilled: 10/13/2013 Logged By: ElW Surface Conditions: Asphalt
Drilling Melhod(s): Hollow Stem Auger Drill Bit SizelType: 6" Total Depth of Borehole: 15.3 feet bgs
Drill Rig Type: Trailer-Mounted Drilling Contractor: Boretec Approximate NJA
Surface Elevation:
Groundwater Level N t t d
and Dale Measured: 0 en co un ere Sampling Method{s): SPT H D I 140 Ib, 30" drop, rope and
ammer a a: cathead
Borehole Backfill: Bentonite Chips Location: 10660 Southeast 176th Street, Renton, Washington
oi
0 c m
'if 1n
12
'w ~ 0
~ 'if
ID .0 Ii ~ Q "' E c ~ '" '" ,.,
0
11
ID :[~ ID (f) i"
~ % 0. > (f) ~ m E ~~ 0 (J > 0 '0 ID ID m ID (f) MATERIAL DESCRIPTION W 0 (f) (1).0 "' :::> :2
-I I , ""hed mck base
8M Brown' '" ) wilh ,ome 9<avel, med'um den,e, mo;,'
--
--§ r-Trace gravel. iron oxide staining
19 13.9
--~
-5-§ SM G,.y s'"y SAND, I, dense. mo,,1 (G',ci,' T'"I
-41 11.9
-lO-s: very dense -50/3" 9.0
-15-o::! 5014" -8.5
Bo,'n9 j at 15'4"
-20---
"
-
-25---
-
-
--
-
Th!l Rile Grou • Inc. y P
17522 Bothell Way NE, Bothell, WA 9B011
Project Name: Benson McDonald's 46-1102 ~ Boring No.: 8-3
Project Number: 2013-365 Sheet 1 of 1
Client: McDonald's USA, LLC
Date(s) Drilled: 10/13/2013 logged By: ElW Surface Conditions: Asphalt
Drilling Melhod(s): Hollow Stem Auger Drill BlI SizefType: 6" Total Depth of Borehole: 16.5 feet bgs
Drill Rig Type: Traller~Mounted Drilling Contractor: Baratee Approximate NJA
Surface Elevation:
:~~u~:t:a~e:a~~~:~: Not encountered Sampling Method(s): SPT HOt 140 Ib, 30" drop, rope and
ammer a a: cathead
Borehole Backfill: Bentonite Chips Localion: 10660 Southeast 176th Street, Renton, Washington
1i c g
w
0; ~
'0; ~ "5
Ii ,g <D .0 C 0; 9 a: E c ,g 0> ~ >-i" 0 1 <D .~ ~ <D 00
~ .c 0. c." > 00 " > 0. E E ~ 0 '-' ;;
U <D <D '" '" 0 ID 00 MATERIAL DESCRIPTION '0
iiJ 0 00 00:3 a: ::> ::;
-0
.. 2~~~h_~,~ over crushed rock base
sili¥ SAND With wmegra:e" medium dense~oiSi (RlL)-- -
---:
~ brown to gray
::i 18 a,s
-5-~ loose, trace organics -
~ 9 15.8
-10-~ -'!raY'i ; sand ~n:r;~!ym den~e, weI 13 15.4
c;gnt , seepage alll'
-
--
-15-~ very dense, contains sand and silt Interbeds -
~ 86 11.8
Boring' i j a116' 6"
-20-I--
-25---
-
The Rile GrOll , Inc. y P
17522 Bothell Way NE, Bothell, WA 98011
Project Name: Benson McDonald's 46-1102 C Boring No.: 8-4
Project Number: 2013-365 Sheet 1 of 1
Client: McDonald's USA, LLC
Date(s) Drilled: 10/13/2013 Logged By: ELW Surface Conditions: Asphalt
Drilling Method(s): Hollow Stem Auger Drill Bit SizeIType: 6" Total Depth of Borehole: 20.5 feet bgs
Drill Rig Type: Trailer-Mounted Drilling Contractor: Baretee Approximate N A
Surface Elevation: '
~~~u;:t:~:a~~~:~: Not encountered Sampling Melhod(s): SPT H D t 140 lb. 30" drop, rope and
ammer a a: cathead
Borehole Backfill: Bentonite Chips Location: 10660 Southeast 176th Street, Renton, Washington
1i
0
~ ~
~
.~ ~ 15
!'i. ~ ~ Ii "" g n: ....
0 !'i. rn i:' .Q 1 m .s= m ~
rn £ 0. Q..Ul ~ ~ ;; > Q. E ~~ u '0 m m rn m MATERIAL DESCRIPTION iIi 0 Ul Ul.c n: ~ -~5"aSPhalt' t mck b.,e
Bmwn SIlty SAND with some gravet, dense, moist
I-
-5-~ 5015" SM Gray silty SAND with some .' ",' ,,' de",e, moist IGlacial Till) 11.6
I"-' -
"
-
-10-~ r--
5016" 9.7 -
"
"
-15-~ 5016" -6.7
-20-~ 5Offi' -6.7
Boring , a"O' 6"
-25---
"
.
-
The Riley Group, Inc,
17522 Bothell Way NE, Bothell, WA 98011
Project Name: Benson McDonald's 46-1102 C Boring No.: 8-5
Project Number: 2013-365 Sheet 1 of 1
Client: McDonald's USA, LLC
Date(s) Drilled: 10/13/2013 Logged By: ElW Surface Conditions: Asphalt
Dnllmg Method(s): Hollow Stem Auger Drill Bit Size/Type: 6" Total Depth of Borehole: 10.5 feet bgs
Drill Rig Type: Trailer-Mounted Drilling Contractor: Boretec Approximate
Surface Elevation: N/A
Groundwater Level N t t d
and Date Measured: a encoun ere Sampling Method(s): SPT HOI 140 Ib, 30" drop, rope and
ammer a a: cathead
Borehole Backfill: Bentonite Chips Location: 10660 Southeast 176th Street, Renton, Washington
1f c
."l
if 00
I~ .~ ~ '0
:!!. if ~
Iii ~ g '" c :!!. '" ~ 0
11
~ .~ ¢:! ~ i" ~ .c 0. c.", > tl > 15. E E ~ 0 u ~ ID ~ ~ 0 ~ MATERIAL DESCRIPTION '0
[[j 0 (J) (J):E '" :;;
-I .. 5" asphal. o,er crushed rock base
G!a~I~:'~i~;ND wi.h some gra,el'o sandy SILT wi.h .race gra,el. ,ery dense, moist
(Glacial
~ ~ 66 ,.4
-5-§ r--
89/11" ,.,
-10-~ 50f6" Ll_ -8.7
1 •• 10' 6-
-15-r--
-20-r -
-25---
-
The Riley Group, Inc.
17522 Bothell Way NE, Bothell. WA 98011
Project Name: Benson McDonald's 46-1102
Project Number: 2013-365
Client: McDonald's USA, LLC
Date(s) Drilled: 10/13/2013 Logged By: ELW
Drilling Melhod(s): Hollow Stem Auger Drill Bit SizelType: 6"
Drill Rig Type: Trailer-Mounted Drilling Contractor: Baretee
Boring No,: 8-6
Sheet 1 of 1
Surface Conditions: Asphalt
Total Depth of Borehole: 11.5 feet bgs
Approximate N/A
Surface Elevation:
Groundwater Level N t t d
and Date Measured: 0 encoun ere Sampling Melhod(s): SPT H D I 140 Ib, 30" drop, rope and
ammer a a: cathead
Borehole Backfill: Bentonite Chips Location: 10660 Southeast 176th Street, Renton, Washington
,; u c rn
i i ~ ~ MATERIAL DESCRIPTION
'i " ~ ';;;
~ 'i v '" Q ~
c ~ '" " 0 1 v ~~ v ~ t Q. 1; rn > E E ~ u v v rn rn 0 v W Q w w:i5 ~
O~~-+--~--+'_~, 1l'~:~~~SANDW'lh'mCkbase
~ 12 l1Q;lrH :oo"a", " concrete debris, trace organics
-
12.2
.. moist (FILL)
-5-~
-~ 6 16.3
i-'Beconnes loose, wei, trace organics -
-~~-B"wmes moist. trace organics -
9 17.7
Bo,i09 I I al11' 0"
-15---
-20--
-
-
-25--
-
The Riley Group. Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name: Benson McDonald's 46-1102
Project Number: 2013-365
Client: McDonald's USA, LLC
<Ii u c
~
1i3 $
·in 15 g $ ~ .n m '" E 0 » ..J
<JJ u
<JJ :c
() 0.
(J) ~
OJ '" 8
COLUMN DESCRIPTIONS
J//I/II1 Key to Log of Boring
.... Sheet 1 of1
MATERIAL DESCRIPTION
9
m
Elevation (feet): Elevation (MSL. feet). [ill Recovery {%}: Core Recovery Percentage is detennined based on
2 Depth (feet): Depth in feet below the ground surface. a ratio of the length of core sample recovered compared to the
3 Sample Type: Type of soil sample collected at the depth interval cored interval length.
shown. m uses Symbol: uses symbol of the subsurface material. m Sample 10: Sample identification number. ffi] Graphic Log: Graphic depiction of the subsurface material rn Sampling Resistance. blows/ft: Number of blows to advance driven encountered.
sampler one foot (or distance shown) beyond seating interval [!] MATERIAL DESCRIPTION: Description of material encountered.
using the hammer identified on the boring log. May include consistency, moisture, color, and other descriptive
text.
FIELD AND LABORATORY TEST ABBREVIATIONS
CHEM: Chemical tests to assess corrosivity
COMP: Compaction test
CONS: One-dimensional consolidation test
LL: Liquid Limit, percent
MATERIAL GRAPHIC SYMBOLS
Asphaltic Concrete (AC)
AF
TYPICAL SAMPLER GRAPHIC SYMBOLS
E Auger sampler
~ Bulk Sample
~ 3-inch-OD California wi
[jJ brass rings
rn CME Sampler
GENERAL NOTES
W Continuous Core
rn Grab Sample
12.S-inch-OD Modified
California wI brass liners
~ Pitcher Sample
ng Moisture (%): Moisture, expressed as a water content.
PI: Plasticity Index, percent
SA: Sieve analysis (percent passing No. 200 Sieve)
UC: Unconfined compressive strength test, Qu, in ksf
WA: Wash sieve (percent passing No. 200 Sieve)
Silty SAND (SM)
Silty SAND to Sandy SILT (SM-ML)
~ 2-inch-OD unlined split
i'i1 spoon (SPT)
~ Shelby Tube (Thin-walled,
IfIJ fixed head)
OTHER GRAPHIC SYMBOLS
---¥ Water level (at lime of drilling. ATO)
~ Water laval (after waiting)
1
Minor change in material properties within a
stratum
-In(erred/gradational contact between strata
-? -Queried contact between strata
1: Soil classifications are based on the Unified Soil Classification System. Descriptions and stratum lines are interpretive, and actual Uthologic changes may be
gradual. Field descnptions may have bean modified to reflect results of lab tests.
2: Descriptions on Ihese logs apply only al the specific boring locations and at the time the borings were advanced. They are not warranted to be representative
of subsurface conditions al other locations Of limes.
The Riley Group. Inc.
17522 Bothell Way NE. Bothell. WA 98011
TilE RILEY GROlJI', INC.
17522 Bothell Way NE
Bot hell, W A 98011
GRAIN SIZE ANALYSIS
ASTM D 421, D 2217, D 1140, C 117, D 422, C 136
PHONE: (425) 415-055\
FAX: (425) 415·0331
PHO.mer TITLE
PRO.meT NO.
TEell/DATE
nenson McDonald's
2013·365
I SAMPLE lDrrVPE 11--..:;Bc..;-I'------1.I----I1
SAMPLE DEPTH 2.5·4.0' ~---~~----~
IlW 10114113
'VATER CONTENT (Delivered Moisture) Total Weighl or Sample Used For Sieve Corrected FOI' Hverosconic Moisture
Wt Wet Soil & Tare (gm) (WI)1-.::2",07",A.:.;0'--l Weight Of Sample (gm) 194.40
WI Dr)' Soil & Tare (gm) (w2)1-..:1."94,,,.:,-4(,-1 -I Tare Weight (gm) H . .50
Weight or Tare (gm) (w3 )1--:"H"'.5::0:--t ____ ----,==:-'(::-W:.;6';-) -;-T:,o:;;t::aj;-:D.:.;ryL...:W~e~igl=lt-"(g"n,,,1),-_,-....:.:18:::5.:.;. 9:..:0'--'--1
Weight ofWulOf (gm) (w4~vl.w2)1-_1:,::3c:;.0:.::0_-l SIEVE ANALYSIS
Weight of Dry Soil (gin) (w5=w2.w3)1-..:1.;;;85",.9:..;0'--1
tvloistme Content (%) (w4/w5)*100 6.99
% COBBLES
%CGRAVEL
%FGRAVEL
% C SANO
% M SAND
% FSAND
% FINES
(l/u TOTAL
DIO (111111)
\)30 (mill)
D60 (mm)
Cu
Co
0.00
4.57
27.86
13.66
18.88
22.65
12.37
100.00
WtRet
+T(lre
H.50
8.50
8 . .50
17.0(1
40.00
(i8.80
94.20
129.30
162.00
171.'i0
171.40
Cumulnlive
(WI-Tare) (%Rctained) % PASS
l(wt rct/w6)·LOOI (lOO-%rct)
0.00 0.00 100.00
0.00 0.00 100.00
0.00 0.00 100.00
8.50 4.57 95.43
31.50 16.94 83.06
60.30 32.44 67.56
85.70 46.10 53.90
120.80 64.98 35.02
153.50 82.57 17.43
162.90 87.63 12.37
162.90 87.63 12.37
.0 1140 1/00 #jOO 000
100 -mmTrl'''''"T-+-"Tr*'' 'rt"=f::=p1":\"t"-t""'M75
'r" rr'F',r+fJI~0'-+rmil'T-f~t"F'''-tFfifTrTT"T-ITTTTTT"rr-1
% 90 tttt-H-I -I-t--+++I --~-H-t++1--1-I-+---I+I·~ ~H-If-+-~+ -+ttf-H-··-t--I--I+H+t-t-+-\--
P
A
S
S
I
N
G
80 -~1---I----+tH --·--\----IH -I-Hf-+-+ --t+++-f-H ++-1 -H+++-I -1-
70 ~ +-+-----~ +-*HI--i--+-t-·· .. ·-I rtHt+-I~----
60 .. -H--+--" H+I-H-+-I--I+++-H I-''k::-+---I -H-t-H---I--H~HI-I-+-1--1----H++t+I-I---j--1 .....,
50 ++-+---j--I . ·H+-HI-I---+I++-HI-+......:r:""-...~I --1++-1-+-1--1--+++1-++-+--+-·.-J+H+l--1 +-+---1
40 ..... ++-+-+--III-tcrt--l-+-I--crHtH--f---+---I ·F!'-i<H--t---j----jJf+l-t 1-+--1---+-~~-++ttt+ 1--1--1--1
30 ~I-H-i-t-t-+--+ ---ttHt+-f-+-t--tH I-Hf-+-+··-t+t+H-I","o--I---1 i'-
100 10 1 0.1
Grain size In millimeters
DESCRIPTION Sill)' gravelly sa,,"
USCS SM I
The Riley Group, Inc.
H+t-t--1-I--tIIH" "I-+-t--f--
0.01 0.001
THE HILEY GROUr, INC.
17522 Bothell Way NE
Bothell, WA 98011
GRAIN SIZE ANALYSIS
ASTM D 421, D 2217, D Il40, C 117, D 422, C 136
PHO.! ECT TIT\ ,E Henson McDollAld's I SAMPLE ID/TYPE
PROJECT NO. 2013-365 SAMPLE DEPTH
TECHIDATE IlW I1l/24/l3
I
rUONE: (425) 415-U55\
FAX: (425) 415-033\
"-2 I
2.5-4.0' I
WATEIl CONTENT {Deliver,d Moi,ture} Total Weight OfSamnle Used Fo!' Sieve Corrected For lIygroscopic Moisture
WI \Vel Soil & Tare (gill) (w1) 429.HO Weight OfSllmple (gm) 378.50
WI I )ry Soil & Tare (gm) (w2) 37R.50 Tme Weight (gill) Uo
Weighl (lfTme (gill) (w3) R.50 (W6) Totol Dry Weight (gOl) 370.00
Weight of Wmer (gm) (w4=IVI-w2) 5UO SIEVE ANALYSIS
Weight or Dry Soil (grn) (w5=w2·w3) 370,00 Cumlllativc
Moisture Contenl (%) (w4/w5)'100 13.86 WtRet (Wt-T"re) (%Ret!}illed) % PASS
+TiUC 1.(\\'1 rdw6)t)OO) (IOO-%Irel)
%) COBBLES 0.00 12.0" 8.50 0.00 0,00 100.00 cobbles
% C GRAVI!:L 0.00 3.0" 8.50 0.00 0.00 100.00 coarse gravel
% FGRAVEL 3.73 2.5 11 coarse gravel
t% C SAND 2.78 2.011 coarse gravel
%MSANO 12.68 IS' 8,50 0.00 0.00 100,00 coarse gravel
% FSAND 39.68 1.0" coarse gravel
% FINES 41.14 0.75" 8,50 0.00 0.00 100.00 fine gravel
% TOTAL 100.00 0.50" fine gravel
0.375" 16.40 7,90 2.14 97.86 fine gravel
010 (mOl) #4 22.30 13.80 3.73 96.27 coarse sand
030 (mill) 1/10 32,(,0 24.10 6.51 93.49 medium sand
060 (111111) #20 medium sand
Cu #40 79.50 71.00 19.19 80.81 fine sand
Cc 1/60 fine S<111(\
1/100 1 92.3() 183.80 49,68 50,32 fine sand
1/200 226.311 217,80 58.86 41.14 fines
PAN 226.30 217.80 58.86 41.14 silt/clay
#0 • 0 <40 11'0 ",00 • 00
-.. -
--[\ --" --
I " I\.. --"-.. -" ---.
-+-+----ttt+++-H--H+-H--+--
-r----
.. " -f--+J-f-H-t+-f
-I-f-----+I+H++-f--.•. --.. ~, .
P
A
5
5
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------ttI-ttl+-H--tttI"III--t--t----t1 -_. ._---f--------+H+t-I-H· . -----ttt-tti-t--I-" -
-t+I-++-+--+' -. -J--+-+-+t+IH+-I "·I-----1t+-H-1--
I--H·-t-1--1------11--"-1-+--+--+++++ ... -"I-I---ttt+H-H""-j--tt+t-H-++--J--
100 10 1 0.1 0,01 0.001
Grain size in millimeters
DESCIlIPTION
I"""'" USCS '----"'S"'M_-II
The Riley Group, Inc.
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, \VA 98011
GRAIN SIZE ANALYSIS
ASTM D 421, D 2217, D 1140, C 117, D 422, C 136
PROJECT TITLE fierlsol) McDonrlld's SAMPLE lDffVI'E
PROJ ICCT NO. 2013-365 SAMPLE DEPTH
TECHfDATE RW 10124113
I
I'HUNI~: (4L~) 41~-U'~1
FAX: (425) 415-0331
II-'! I
2,5-4.11' I
WATElt CONTENT (l1eliv,,·,d Moistllr,) Total Weight OfSaml1le Used For Sieve Corrected POI' Hygroscopic Moi!:-iture
Wt Wet Soil & Tlire (gm) (wi) 320.90 Weighl O[Samplc (gm) 296.30
WI [J,y Soil'" Tare (gill) (w2) 296.311 Taro Weight (gin) 8.50
Weigh( of Tare (gm) (w3) 8.50 IW6) Tolal Dry Weight (gOl) 287.8n
Weight of Water (gill) (\V4~wl-w2) 24.60 SIEYE ANALYSIS
Weight of Dry Soil (gill) (w5~w2-w)) 287.80 CUlUulntjyt;
Moisture Contenl (%~) (w4!w5)* 100 8.55 WI Rei (Wt-IHle) l%Relained) %PASS
+Tnre Hwt reIJ~\'ti)~IOOl (lOO-%ret)
% COIl ilLES 0.00 ]2.011 8.50 o.on 0.00 100.00 cobbles
0/c) C CRAVEL 14.1 I 3,()" 8.50 0.00 0.00 100.00 conrse gravel
%FGRAVl!:L 17.48 2.5" coarse gravel
% CSAND 5.84 2.0" coarse gravel
% /'\'1 SAND IH.17 1.5" ~.5(J 0.00 0.00 100.00 coarse gravel
II/II F SAND 20.60 1.0 11 coarse gravel
% )i'INES 23.80 0.75" 49.10 40.60 14.11 85.89 line gmvcl
% TOTAL 100.00 0.50 11 tine gravel
0.375" 88.70 80.20 27.87 72.13 line gravel
HIO (111m) #4 99AO 90.90 31.58 68.42 coarse sand
])30 (mm) #10 116.20 107.70 37.42 62.58 medium sand
060 (mm) 1/20 medium sand
Cu #40 168.50 160.00 55.59 44.4t fine sand
Cc #60 line sand
#100 216.30 207.80 72.20 27.80 fine sand
#200 227.80 219.30 76.20 23.80 fines
PAN 227.80 219.30 76.20 23.80 silt/clay
.. 1~.7 ~ 375" .. #10 • 0 .40 1j60 '100 ,00 100 I % 90 . _., .•. ". . . , . ._ . --... -
~ 80· .... ....... .-.---------
P 70· .... r -..... ~ "._-
A --.. 60 . -.. _., ,.,
"'
-. --
S 50 -1 . -.-•... .-r--s 40 . I··· -.-. --r--
I 30 . . -r-.:: -
N 20 . -. .. -
G 10 , . __ .. . .. -.. -i 0
1000 100 10 1 0.1 0.01 0.001
Grain size In millimeters
LlESCllll'TION Silty gravelly sand
lISCS SM I
The Riley Group, Inc,
nlto: I(ILI<,Y l;I<UVI', me.
17522 Bolhell Way N E
BOlhell, \VA 98011
GRAIN SIZE ANALYSIS
ASTM D 421, D 2217, D 1140, C 117, D 422, C 136
PROJECT TITLE Gellson MClJOIlIlIiII,s I SAMPLE JD/TYPE
PROJECT NO, 2013·365 SAMPLE DEPTH
TECHIDATE nw 10/24/13
I
J~HUI"HI..: t'b:::l} ql~-U:l:::'ll
FAX: (425) 415-0331
11·5 I
5-6.S' I
'VATER CONTENT (Delivel'ed Moisture) Tot<tl Weiblht OrSam~lc Used Fo1' Sieve Corrected Por I-In roscoJ1ic Moisture
WI Wet Soil & Tare (gm) (wI) )23.50 Weight OfSmnple (gin) 296.50
Wt Dry Soil & Tare (gill) (w2) 296.50 Tarc Weight (gill) 8,51l
Weight ofTarc (gm) (w3) 8,50 (W6) Total DIY Weight (gm) 288,00
Weight ofWaler (gin) (w4~wl·w2) 27,00 SIEVI~ ANAI,vSIS
Weight of Dr)' Soil (gm) (w5~w2-w3) 288,00 Cumulative
Moi~llll'e Content (%) (w4/w»)*100 9.38 WI Ret (WI·Tore) {%RetElioed) % PASS
+Tare {h~! tclfw6j t lOOl (lOO-%l'et)
o/(JoCOnnLES 0.00 12,0" 8.50 0.00 0.00 100.00 cobbles
%C GRAVEL 0.00 3,0" 8.50 0.00 0.00 100.00 coarse grm,e1
% FGHAVli:L 7.29 2.5" coarse gravel
%CSAND 3.06 2.0" coarse gmvd
% M SANIl 10.56 1.5" X.50 0,00 0.00 100,00 coarse gravel
% F SAND 28.09 1.0 t• coarse gravel
% FlNICS 51.0J 0.75" X.50 0,00 0.00 100,00 tine gravel
% 1'OTAL 100.00 0,50" fine gravel
0.375" 22.50 14,00 4.86 95.14 fille gravel
DIO (mill) #4 29.50 21.00 7.29 n.71 coarse sand
D.IO (Ill"') 1110 38.30 29.80 10.35 89.65 medium .sand
060 (111111) #20 medhun salld
Cu #40 OR.70 60.20 20.90 79.10 fille sand
Cc #60 tine sand
#\00 134.RO 126.30 43,85 56.15 fine smld
#200 149,611 141.10 48,99 51.01 fines
PAN I 49,r,O 141.10 48.99 51.01 silt/clay
, .. " " 1"] " .375" .. #10 .0 #~o ,fl60 #100 .00 100 .
-I
I % 90 -.. -...... _. ........ ,---. --------..:..
80 ... ---..... -
P 70 -- -. ... -_ .. " ----
A 60 -"-.... '. .. _--.. -....:: ' ...
S 50 ...... _ ......... __ . --.-.-.'~
S 40 --I .•. _.-. ~ --
I 30· ....... --
N 20· I ......
.
I
_ ...
G 10 -I I O·
1000 100 10 1 0,1 0.01 0,001
Grain size in millimeters
DESCRIPTION Sandy silt with Irnce gravel
USCS MI-I
The Riley Group, Inc.
f ,
URS Memorandum
DlIle: August 21, 2012
To: Wayne Shores (Velmeir Companies)
Cc: Geza deGall (Velmeir Companies), Katy Chaney (URS)
From: Nate Larson, PE, PTOE
Subject: Renton Proposed Pharmacy: Traffic Generation and Distribution/Access
City of Renton Reference PREI2-0n
This memo summarizes the traffic generation and distribution for a proposed "pharmacy with drive-
thm" at 10706 SE Carr Road in Renton, W A. It has been prepared in response to a request by City of
Renton staff for the purpose of demonstrating two important things: (1) that the proposed use would
generate less traffic than the existing (or most recent) uses, which are presumed to be permitted, and (2)
that the proposed plan for access is necessary for the successful operation of the proposed use on the
site.
City staff has agreed at our Preapplication Meeting (09/1312012) that if the proposed pharmacy would
generate fewer trips than the current uses on the site, then neither transportation impact fee payment
(based on any net new daily trips) nor a full traffic impact analysis (required for projects generating
more than 20 net new p.m. peak hour trips) will be required.
Traffic Generation
Traffic generation characteristics for various land uses have been studied since the 1950's and are
documented by the Institute of Transportation Engineers (ITE) in its Trip Generation handbook. The
current edition of this resource, which is the nationwide industry standard, is the 8th edition. At the
City's direction, the ITE Trip Generation handbook, 8th Edition, has been used for this analysis to
estimate number of trips the current and proposed land uses on the site based on their size in square feet,
both on a daily basis and in the p.m. peak hour, which is at this location, like most situations, the busiest
traffic hour on the adjacent streets and therefore the basis for assessing traffic operations service quality,
and therefore, facility design decisions. In traffic generation analysis, a "trip" is an automobile journey
that either begins or ends on the site in question. The comparison of daily and p.m. peak hour traffic
generation hetween the current and proposed land uses is shown in the table below. Rates are expressed
in units of trips per 1,000 square feet. No allowances or deductions are made for internal capture.
URS
Use
Pharmacy w IDri ve Thru
Square
Feet
16,273
ITELand
Use Code Rate
Proposed Use
881 88.16
Current Uses
Daily PM Peak Hour
Rate I Trips
1435 10.35 168
Page 2 of2
Ratio of
Daily to
PM Peak
8.5
Health Club 20,272 492 32.93 668 3.53 72 9.3
I. ............ .......................... .. "'(5;S'70'" ·······814····--4432 '''-304'' --2'.--],C-f---j(j-· .. ···]'6.4······
.. Spe~i~lty.l3:~t~il .............................. _ ....... -........ .. -.......................... ~: .. ,-_ ... -.... -.__ .................... -'--................. -1 .... ..
IPvernIDrinking Place .............. 3,<1QQ ........... 925 140.29: 420 1}.}4 .. _~. ___ .!:2:~..
1 Restaura I11._ .. .... .. . ...... I-.!~63L ... _ .. .2~.'2.._.. 127.15 ....... ?Q.? .... _ . ....!.!: 15 18 11.4
Office 1,000 710 11.01 12 1.49 1 7.4 ............................................................ 'T'-" -.... _ ............ _ ..... _._.. . ..... --... -.. . .. __ ............. _ ... .
Coffee Shop wlDriveThru 800 937 818.58 654 42.93 34 19.1
Total for Current Uses 33,577 2,266 178
Net New Trips Generated -831 -10
Notes: 1. Daily trips rounded to the nearest even number because all vehicles that enter In a day also leave that day.
2. 1TE does not have a daily trip rate for Use 925. Daily rate shown is based on a combination of the
Restaurant and Specialty Retail {Iaily-to-PM ratios.
3. Coffee shop is in a separate bllilding located in the southeastern part of the site.
The estimates in the table indicate that the proposed traffic generation, both daily and p.m. peak hour,
would be lower with the proposed use than for the current uses, and therefore indicate that neither
impact fee payment nor a full traffic impact study will be required.
Traffic Distribution/Site Access
The distribution of traffic from and around the site determines how site traffic will use the available
access points (driveways), which in turn helps to determine how those access points need to be
configured and controlled to facilitate safe, efficient, and intuitive movements for traffic entering and
leaving the site.
P.M. peak hour traffic using the site is distributed to the four primary arterial routes around the site as
follows:
• 25% to/from the north on Benson Drive SouthiSR 515
• 25% to/from the south on 108 1h Avenue SE
• 20% to/from the west on SE Carr Road
• 30% to/from the east on SE 1761h StreetlSE Petrovitsky Road
These are rough estimates, and it is also possible that negligible percentages of traffic could also be
oriented to the small residential area northwest of the site and to the shopping center across SE Carr
Road to the south. Such small traffic volumes are unlikely to have any substantive effect on traffic
operations and are therefore excluded from this analysis.
ITE data indicate that a pharmacy with a drive-through window exhibits balanced inlout traffic
distribution in the p.m. peak hour (50% in, 50% out). Because this site and the surrounding area are
south and east of the region's proximate major office/industrial employment centers and limited-access
Memo Renton Proposed Pharmacy: Traffic Generation and Distribution 912I/2012
DRS , Page 3 of 3
highways (l-405, SR 167), there is a fairly strong directional bias in the p.m. peak hour for traffic going
southbound and eastbound (60%) rather than northbound and westbound (40%).
With these assumptions in mind and the total number of trips indicated earlier in the Traffic Generation
section (173), p.m. peak hour traffic volume to and from the site is expected to be distributed as follows:
• 21 trips in from the north, 21 trips out to the north (Benson Drive SouthlSR 515)
• 21 trips in from the south, 21 trips out to the south (108'h Avenue SE)
• 17 trips in from the west, 17 trips out to the west (SE Carr Road)
• 25 trips in from the east, 25 trips out to the east (SE 176'h StreetlSE Petrovitsky Road)
For the purpose of this analysis, there will be three access points to the site, as shown on the sketch
below. North is toward the top of the page and the sketch is not to scale.
, ,
""""' ...
West
Access -=
-.!m'~
-~
~1I!i.~_--"
-...
-.~
Note: TIle proposed project would close the existing driveway on SE Carr Rd. between Benson Drive S. and the
"SOl/lh access" indicated.
The south access will be the primary choice for all site traffic oriented to the west and south, as well as
all inbound traffic from the east. The north access is highly likely to serve all inbound traffic from the
Memo Renton Proposed Pharmacy: Traffic Generation and Distribution 9/21/2012
•
;
DRS Page 4 of4
north, but cannot serve the reverse trips (outbound to the north) because the 174'h/Benson intersection is
restricted to right-in and right-out movements. The west access is expected to be sparsely used at most
times of tbe day. The following chart indicates which of the eight primary movement patterns (In/Out, 4
directions) are expected to use which of the three access points for direct movement to and from the site,
and the number of vehicles expected to make that maneuver, based on the distribution estimates shown
on the previous page.
@>(TlIl'Il Direction: # of vehicles) = Major Use o = Minor Use X = LittlelNo Use, or Not Allowed
Movement North Access South Access West Access
In from the North on Benson Drive South/SR 515 • R: 21 X X
Out to the North on Benson Drive SouthlSR 515 X • L: 21 X
In from the South on 108'" A venue SE X • R: 21 X
Out to the South on 108'h A venue SE o R:7 • L: 14 X
In from the East on SE 176'h StreetlSE Petrovitsky Road X e R: 25 X
Out to the East on SE 176'h StreetlSE Petrovitsky Road OR: 8 e L: 17 X
In from the West on SE Carr Road X eL:17 X
Out to the West on SE Carr Road X e R: 17 X
The primary function of the north access is to allow convenient inbound access to inbound traffic
arriving at the site from the north. The west access would primarily serve any small amounts of site
traffic oriented to the localized residential areas northwest of the site, as well as some large trucks (three
or more axles) that might visit the site to deliver goods, provide maintenance, or remove waste. Due to
its proximity to the pharmacy's customer entrance, where most vehicles accessing the site will park, the
south access would carry most of the traffic into and out of the site, as it does currently (in combination
with the other SE Carr Road access). An estimated total of 52 vehicles (or one every 70 seconds, on
average) would desire to turn left out of the south access in the p.m. peak hour.
The team was made aware of a potential intersection improvement at the Benson/Carr intersection that
could impact access to the site. City staff has indicated that this improvement, widening SE Carr Road
(west of Benson Drive S.) to the north to expand the intersection's westbound left turn pocket from one
lane to two lanes, could include the installation of a median curb treatment on SE Carr Road that would
prohibit left turns into and out of the site's south access. As indicated in the chart above, such a
treatment would remove the primary (or only) reasonable site access for half of the site's movements.
The potential owner of this site's very long history of developing and operating pharmacy outlets
nationwide has shown that simple and direct site access is crucial to the success of this type of retail use.
Removal of left tum capability at this location would represent a barrier to the eventual competitiveness
of the pharmacy that is likely to force the owner to consider another location.
Memo Renton Proposed Pharmacy: Traffic Generation and Distribution 912112012
DRS Page 5 of 5
In addition [0 the vital role full access at this location plays in the eventual success of this project, there
are six other considerations that I believe the City should take into account in its decision regarding
whether to include a median left turn restriction on SE Carr Road, as follows:
I. The site has functioned with not one, but two full-movement (unrestricted) driveways on SE Carr
Road since it opened in its current configuration;
2. As shown in the previous section of this memo, the proposed use would generate even less traffic
than the current site is designed and permitted for;
3. While the left turn restriction is designed to address of a p.m. peak problem, pharmacy traffic
would be substantially inconvenienced all the time;
4. The left turn restriction would force some site traffic (outbound to the north) to cut through the
residential area to use the next-least-inconvenient route back to Benson Drive S.;
5. The left turn restrictions are unnecessary because even during p.m. peak conditions, the
operation of the two proximate traffic signals creates gaps in SE Carr Road traffic that are
generally sufficient for site access left turns to occur without major delays;
6. A physical median treatment (curb) restricting could increase travel distance, and therefore time,
for emergency response vehicles accessing the site.
In summary, both daily and p.m. peak hour trip generation estimates indicate that the proposed site use
would generate less traffic than the current/recent uses on the site, and the proposed traffic distribution
and access configuration indicates that all four movements must be allowed at the SE Carr Road
driveway.
Please don't hesitate to contact me at nate.larson@urs.comor206.438.2353 if you have any questions
regarding the information provided here.
Memo Renton Proposed Pharmacy: Traffic Generation and Distribution 912112012
j
] ISSUED FOR PERMIT
]
il
i DRAINAGE PLAN
I TECHNICAL INFORMATION
I REPORT
I Velmeir Retail Pharmacy
I
I
I Prepared/or
I
The Velmeir Companies
5757 West Maple Road
West Bloomfield, MI, 48322
I August 13, 2013
I
I
1501 Fourth Avenue, Suite 1400
I Seattle, WA 98101-1616
(206) 438-2700
Job No: 12943878
I r~' -~
I i .. ".1,
This document has been prepared under the supervision of a registered professional engineer.
O\'~: O1/16! \4-
Date Signed:_-'Ae>.u"'gus.,.,.t>--1..,3"" ..... 2""O...,13"--_
~
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CONTENTS
1.0 PROJECT OVERVIEW .................................................................................................................. 3
1.1 EXISTING SITE ................................................................................................................. 3
1.2 PROPOSED PROJECT ...................................................................................................... 4
1.3 SOILS ................................................................................................................................. 4
2.0 CONDITIONS AND REQUIREMENTS SUMMARY .................................................................. 4
3.0 OFFSlTE ANALYSIS ..................................................................................................................... 8
4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ............ 10
4.1 PART A-EXISTING SITE HYDROLOGY .................................................................. 10
4.2 PART B -DEVELOPED SITE HYDROLOGY ............................................................. 10
4.3 PART C -PERFORMANCE STANDARDS .................................................................. 11
4.4 PART D -FLOW CONTROL SYSTEM ........................................................................ 12
4.5 PART E -WATER QUALITY SySTEM ....................................................................... 13
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN ............................................................. 13
5.1 EXISTING COLLECTION AND CONVEYANCE SYSTEM ....................................... 13
5.2 PROPOSED COLLECTION AND CONVEYANCE SYSTEM ..................................... 13
6.0 SPECIAL REPORTS AND STUDIES .......................................................................................... 14
7.0 OTHER PERMITS ........................................................................................................................ 14
8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION .......................................... 14
8.1 PART A-EROSION AND SEDIMENT CONTROL .................................................... 14
8.2 PART B-SPILL PLAN DESIGN ................................................................................... 16
9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT .. 16
10.0 OPERATIONS AND MAINTENANCE MANUAL .................................................................... 16
11.0 REFERENCES .............................................................................................................................. 25
June 2013
TABLES
TABLE 1: EXISTING SITE CONDmONS ............................................................................................... 3
TABLE 2: PROPOSED SITE CONDITIONS ........................................................................................... ..4
TABLE 3: SITE CONDmON AREAS SUMMARY ................................................................................. 4
TABLE 4: KCRTS MODEL INPUTS ....................................................................................................... 10
TABLE 5: PEAK FLOW RATES ............................................................................................................. 10
TABLE 6: FLOW CONTROL FACILITY SUMMARy .......................................................................... 12
FIGURES
FIGURE I: TIR WORKSHEET
FIGURE 2: SITE LOCATION MAP
FIGURE 3: DRAINAGE BASINS, SUBBASINS AND SITE CHARACTERISTICS
FIGURE 4: SOILS
FIGURE 5: PROPOSED SITE CONDmONS -PHASES 1 AND 2
SELECT DESIGN DRAWINGS
CT. 1 TITLE SHEET
1 OF 1 ALTAlACSM LAND TITLE SHEET
Cl.3 UTILITY PLAN-SITE
Cl.4 GRADING PLAN-SITE
Cl.6 DETAILS-SITE
Cl.7 STORMW ATER PLAN-SITE
Cl.8 STORM PROFILES-SITE
C3.3 UTILITY PLAN-PUBLIC
C3.4 GRADING PLAN-PUBLIC
C3.6 STORMWATERPLAN-PUBLIC
C3.7 STORMWATERPROFILES-PUBLIC
APPENDICES
APPENDIX A: DESIGN STORMWATER CALCULATIONS
APPENDIX B: OFFSITE ANALYSIS
APPENDIX C: BOND QUANTITY WORKSHEET
APPENDIX D: DECLARATION OF COVENANT
APPENDIX E: KING COUNTY STORMW ATER POLLUTION PREVENTION PLAN RELEVANT
ACTIVITY WORKSHEETS AND BMP INFO SHEETS
ii June 2013
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1.0 PROJECT OVERVIEW
The Velmeir Companies are planning to redevelop three acres located on the northwest Comer of
Southeast Carr Road and Benson Drive South in Renton. Vehicle access to the site under existing and
proposed conditions is from Southeast Carr Road and Southeast 174tb Street.
Existing buildings on site are planned to be demolished and the site developed in two phases.
Redevelopment for both Phases I and 2 are addressed in this report. The first phase would include
grading and utility work for the entire site and construction ofan approximately 16,300 square foot retail
building at the south side of the property. The proposed building would be a pharmacy with a drive-
through and include 69 parking spaces. Phase 2 would include a retail fast food restaurant on the north
side of the property. The proposed footprint of the retail fast food restaurant is 4,300 square feet.
Work within the public right-of-way (ROW) is required by the City of Renton to obtain project permits
and will include sidewalk improvements along Benson Drive South and street and sidewalk
improvements along Southeast 174th Street. New impervious area within the ROW includes 2,030
square feet of new sidewalk along Benson Drive South and 4,610 square feet of added impervious of road
and sidewalk along Southeast 17 4th Street; for a total new impervious area of 6,640 square feet. Replaced
impervious area within the ROW of 174tb Street is 4,225 sf. Total new plus replaced impervious within
the ROW is 10,865 square feet.
Flow control and water quality facilities for the proposed site have been developed to address stormwater
runofffor the entire 3.02 acres.
This drainage report was developed in accordance with the 2009 King County Surface Water Design
Manual (SWDM) and the 2009 City of Renton Amendments to the SWDM, Chapter I and 2. The
Technical Information Report Worksheet includes project-specific data and is presented as Figure I. The
site is located in Southeast Renton, as shown on Figure 2: Site Vicinity Map. The existing site conditions
are presented on Figure 3: Drainage Basins, Subbasins and Site Characteristics.
1.1 EXISTING SITE
The site is presently developed with two commercial buildings, one approximately 30,000 square feet and
one approximately 600 square feet, as shown on Figure 3. Land use consists of existing buildings, paved
surfaces (vehicle driveways and parking), and a few small vegetated areas located at the southeast and
northeast comers of the site. See Table I for a summary of the existing site conditions. The existing site
slopes from east to west with slopes ranging from 2 to 9 percent.
Stormwater from the existing site is collected using catch basins and is conveyed through storm drainage
pipes by gravity to the southwest comer of the site, where it leaves the sites and enters the public storm
drainage system comprised of ditches and drain lines. Presently, there are no detention or water quality
treatment facilities on site.
Table 1: Existing Site Conditions
Condition Impervious (acres) Landscape Total
Building Pavement (acres) (acres)
Existing 0.70 2.27 0.05 3.02
3 Jun. 2013
1.2 PROPOSED PROJECT
The proposed project improvements for Phases I and 2 are shown on the Figure 5. The proposed land use
represents the entire 3.02-acre site and includes two buildings (pharmacy and future fast food restaurant),
paved areas, and landscaping. The project will include new catch basin inlets, storm drainage pipes, flow
control and water quality facilities, and relocated utilities. Building fuotprints, as well as areas of
impervious and pervious surfaces for the proposed site conditions (phases I and 2) are presented in Table
2. The project design drawings present Phase I only, and the area where the future fast food retail
building is planned will be temporarily seeded with grass.
Table 2: Proposed Site Conditions
Condition IlI!Pervious (acres) Landscape Total
Bu\ldln~ Pavement (acres) (acres)
Pharmacy 0.37 1.03 0.27 1.67
Future Fast Food 0.10 0.71 0.29 1.10
Right-of-Way 0.00 0.25 0.00 0.25
Total 0.47 1.99 0.56 3.02
Table 3 compares the existing and proposed condition for the site.
Table 3: Site Condition Areas Summary
Condition Impervious (acres) Landscape Total Percent
Buildlne: Pavement (acres) (acres) Impervious
Existin2 0.70 2.27 0.05 3.02 98%
Proposed 0.47 1.99 0.56 3.02 82%
1.3 SOILS
The geotechnical report (Terracen Consultants,loc., October 2012) describes site soils from a depth of3
to 10.5 feet as brown silty sand with trace fine gravel (weathered glacial till, medium dense to dense).
Soils below 10.5 feet to the 1imitofthe borings consist of gray silty sand with a trace offine gravel
(unweathered glacial till, very dense).
Based on the Soil Survey Area: King County Area, Washington (USDA NRCS, 2012), site soils are
classified as Arents, Alderwood material, 6 to 15 percent slopes (Ame). The Alderwood series consists
of moderately well drained, undnlating to hilly soils that have dense, very slowly permeable glacial till at
a depth of20 to 40 inches; on uplands and terraces. See Figure 4: Soils. The well drained soils were
likely removed during the previous development and current conditions are pavement and buildings
founded On imported aggregate and pavement placed over glacial till.
2.0 CONDmONS AND REQUIREMENTS SUMMARY
A pre-application packet was submitted to the City of Renton for the proposed redevelopment project
The City's response related to surface water was documeoted in a Pre-Application Memorandum
4 June 2013
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addressed to Rocale Timmons, Planner and prepared by Jan lilian, Plan Review, for the City of Renton on
September 10, 2012. The memorandum stated that a drainage plan and drainage report will be required
with the site plan application. The report sball comply with the 2009 King County SWDM and the 2009
City of Renton Amendments to the SWDM, Chapter 1 and 2. All core and any special requirements sball
be contained in the report.
The project falls under Full Drainage Review, per Section 1.1.2.3 of the City of Renton Amendment to
the SWDM. For a full drainage review, demonstration of project compliance with the following
requirements is necessary.
Core Requirement #1: Discharge at tbe Natural Location
Stormwater runoff from the proposed project will discharge at the same location as present.
Core Requirement #2: Offsite Analysis
There is no surface water running onto the site; an upstream analysis does not apply.
A Level I downstream analysis was completed for the project and is included in Section 3 of this
report.
Core Requirement #3: Flow Control
Flow Control Facilities
The area specific flow control requirements under Core Requirement #3 apply. Based on the City's
flow control map, this site falls within the Flow Control Duration Standard, Forested Site Conditions.
Improvements on private property will include flow control facilities. Flow control facilities will
account for onsite improvements as well as improvements within the ROW.
A comment provided by the City of Renton on the January 9, 2013 version of this report stated that
"the applicant will need to include in the TIR an explanation of bow the project qualifies for the 0.1
cfs exception including KCRTS output files." See Section 4.0 of this report for predeveloped and
proposed flows.
Flow Control BMPs
According to Section 1.2.3 of the SWDM, all proposed projects, including redevelopment projects,
are to provide onsite flow control facilities or flow control BMPs, or both. Flow control BMP
requirements are discussed in Section 1.2.3.3 (P-ISO) of the SWDM. The goal is to apply flow
control BMPs to new impervious surfaces to the maximum extent practicable without causing
flooding or erosion impacts. The minimum levels of application are specified in SWDM Section S.2.
Design and details for flow control BMPs are included in SWDM Appendix C.
The proposed project provides a reduction in impervious area from approximately 98% to 82% (see
Table 3). New impervious areas were necessary within the ROW (6,640 square feet or O.IS acres).
Replaced impervious for the overall project is approximately 2.4S acres.
Evaluation of flow control BMPs for the improvements to the ROW is necessary according to the
SWDM. ROW improvements are less than 22,000 square feet; therefore, the improvements fall under
the small project flow control BMP guidelines. The net new impervious area in the ROW along
5 June20J3
Benson Drive South is 2,030 square feet. The net new impervious area in the ROW along Southeast
174th Street is 4,610 square feet. The total area of the frontage to centerline of road is 8,835 square
feet. Full infiltration or dispersion of stormwater anywhere onsite is not practical due to limited soil
and site conditions. Flow control BMPs are not allowed within the ROW.
There are three areas onsite which would allow limited infiltration of stormwater. Two islands in the
middle of the site will have curb cuts and allow stormwater flow into the landscaped areas. Each
island is approximately 600 square feet.
There is a vegetated area along the south edge of the site which will be graded similar to a swale/rain
garden and will allow treatment and infiltration of stormwater. This area (within private property) is
approximately 5,800 square feet.
In all, approximately 7,000 square feet of pervious area will be graded and vegetated to promote
infiltration and treatment of stormwater. This area is approximately equivalent to the added
impervious area within the ROW. These types of Flow Control BMPs will supplement the proposed
Flow Control Facility and Water Quality Treatment BMPs required.
Core Requirement #4: Conveyance System
New conveyance lines on site will be sized for the 25-year storm and evaluated using the 100-year
storm to demonstrate that overflow does not create or aggravate a severe flooding or erosion problem
(SWDM Section 1.2.4.1).
The connection to the downstream/offsite system was evaluated (see Section 3 of this report) to
determine ifbackwater concerns exist in the downstream drainage system. The existing conveyance
systems adequately convey existing storm flows and are not expected to experience an increase in
flow characteristics as a result of the project. In fact, flows leaving the site are expected to decrease
because there will be less impervious area and a detention facility is planned to be installed. SWDM
Section 1.2.4.2 states that these systems do not need to be analyzed for conveyance capacity.
Core Requirement #5: Erosion and Sediment Control
Required erosion and sediment control (ESC) measures, as detailed in the King COUDty Erosion and
Sediment Control Standards and SWDM Section 1.2.5, will be incorporated into the project design,
and implemented and maintained during the construction phase. Refer to Section 8 for the minimum
ESC measures that the contractor will be required to implement. Temporary and permanent erosion
and sediment control plans are shown on the proj ect drawings.
Core Requirement #6: Maintenance and Operations
Drainage facilities at the project site will be privately maintained by the property owner in accordance
with SWDM Appendix A; Maintenance Requirements for Flow Control, Conveyance and WQ
Facilities. SWDM Appendix C includes maintenance requirements for Flow Control BMPs. These
are described in Section 10 of this document.
Declaration of Covenant for Inspection and Maintenance of Stormwater Facilities and BMPs has been
prepared, see Appendix C.
6 June 2013
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Core Requirement #7: Finaucial Guarantees and Liability
Tbe property owner will be responsible for the construction of site facilities and restoration and site
stabilization; as well as drainage defect and maintenance. The site will be privately maintained.
Core Requirement #8: Water Quality
The project is a commercial site resulting in more than 5,000 square feet of pollution generating
impervious surface. Enbanced basic water quality treatment per section 1.8 of the SWDM as amended
by the City sball be provided.
Two stormwater quality fIlters (Contecb StorrnFilter or equivalent) in series with two different media
types are planned to be constructed witbin the project site to address water quality requirements. See
Section 4 and Appendix A for a detailed description of water quality analyses and design.
Special Requirement #1: Other Adopted Area-Specific Requirements
Special drainage requirements are listed in SWDM Section 1.3. A State Environmental Policy Act
(SEPA) determination will be submitted to the Department of Development and Euvironmental
Services (DDES) under separate cover. Special requirement #1 includes the following:
• Critical Drainage Areas (CDAs): Not applicable. The site is not witbin a CDA.
• Master Drainage Plans (MOPs): Not applicable.
• Basin Plans (BPs): Not applicable.
• Salmon Conservation Plans (SCPs): Not applicable.
• Stormwater Compliance Plans (SWCPs): Not applicable.
• Lake Management Plans (LMPs): Not applicable.
• Flood Hazard Reduction Plan Updates (FHRPs): Not applicable.
• Sbared Facility Drainage Plans (SFDPs): Not applicable.
Special Requirement #2: Flood Hazard Area Delineation
The project is not located witbin the 100-year flood plain; special requirement #2 does not apply.
Special Requirement #3: Flood Protection Facilities
Tbis requirement does not apply to the proposed project.
Speeial Requirement #4: Source Control
Water quality source controls prevent rainfall and runoff water from coming into contact with
pollutants, thereby reducing the likelibood that pollutants will enter public waterways and violate
water quality standards or County stormwater discbarge permit limits. A stormwater pollution
prevention manual was prepared by King County for citizens, businesses, and industries to identify
7 June 2013
and implement source controls for activities that often pollute water bodies. Source control measures
shall comply with the King County Stormwater Pollution Prevention Manual (SPPM) (King County,
2009a). Relevant Sections are included in Appendix E.
Source control BMPs for this site will include permanent vegetation and soil stabi1ization to limit
erosion of soil within landscaped areas. These source control BMPs shall comply with Activity A-26
in Appendix E (King County, 2009a) Remaining areas will receive permanent cover (pavement or
buildings). Parking lots and sidewalks will be maintained to limit the amount of sediment and litter
that could enter the onsite stormwater system and detention/water quality systems in accordance with
Activity Sheets A-31 and A-32 in Appendix E (King County, 2009a). The detention pipe system and
water quality filtration system will be periodically inspected, maintained, and cleaned in order to
minimize the chance for accumulated material within the system to leave the site. Cartridges in the
water quality system will be monitored routinely and replaced when needed. The storm drainage
system will comply with Activity Sheet A-I in Appendix E (King County, 2009a).
Special Requirement #5: on Control
No fueling is planned to occur on site, the site will not be used for vehicle maintenance, and it is not
considered a high use site. Oil control does not apply to this project
3.0 OFFSlTE ANALYSIS
An offsite analysis as stipulated in the 2009 SWDM and the 2009 City of Renton Amendments requires a
Level I analysis of the downstream system leaving the project site to be evaluated. The Level 1 analysis
includes the following tasks:
• Task I -define and map the study area,
• Task 2 -review resources,
• Task 3 -inspect the study area,
• Task 4 -describe the drainage system and its existing and predicted drainage and water quality
problems, and
Tasks 1 and 2 were completed using the City of Renton (COR) on-line mapping system to identity the
study area and review existing storm drainage facilities on site and within the study area. The study area
includes the project site and the downstream drainage system within Yo mile. The available mapping from
the City and the topographic survey completed for the project indicate that there is no surface water
running onto the site; therefore, no upstream analysis was conducted For Tasks 3 and 4, a field
inspection was performed by David Huang, PE ofURS on December 11,2012. The field inspection
included observing the drainage system within the study area to identity and characterize drainage
components and potential storm water issues, such as erosion or flooding, for the existing and proposed
site condition. During the site visit, the weather was intermittent rain with temperatures in the mid-40's.
The site is currently developed and consists of a large paved parking area with two buildings. No
stonnwater detention or water quality facilities were found on site. During the Level 1 field visit and
evaluation of the existing site, no drainage or water quality issues were found on site or within the study
area.
8 June 2013
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Supporting documents for the downstream analysis are included in Appendix B of this report.
Documents include a map tracking the route of the downstream system leaving the site and the Off-site
Analysis Drainage System Table from the 2009 SWDM describing the different drainage components in
detail. Photos of the downstream drainage system are also provided in Appendix B.
Two locations where stormwater could potentially discharge from the site were reviewed in the field. The
first location is at the northwest portion of the site where stormwater enters a catch basin (labeled as "I"
on the Appendix B Map) and drains to a series of roadside ditches and culverts along the south side of SE
174111 Street It was determined that this catch basin is locatcd in the right-of-way, therefore, not located
onsite. The flow path was followed and is described here and mapped for information only. The ditch
segments are overgrown with vegetation and were observed to contain trash. There were no observations
of scouring or erosion in the ditches or overtopping of the culverts during the field visit. The ditch-
culvert flow drains into a piped system running along the south side ofSE 174111 Street and crosses to the
northwest comer of the intersection at SE 174 Street (103nl Avenue SE) and S 36111 Place before leaving
the roadway to drain down a steep sloped area off the west side ofl03nl Avenue SE. The system outfalls
to a wooded area beyond the Y. mile flow path distance. Storm drainage along this flow route was
observed to be consistent with the City's storm sewer mapping.
The second location observed in the field is the southwest comer of the site. All site stormwater
discharges to the southwest comer; either through a catch basin (labeled as "27" on the Appendix B Map,
corresponding to about 98% of the site drainage area) or a 3-inch diameter pipe under the sidewalk
(labeled as ''29'' on the Appendix B Map, corresponding to about 2% of the site drainage area).
Consistent with City mapping, the catch basin connects to another catch basin located ul'stream of a grass
lined swale that runs around the NE comer of the intersection ofSE Carr Road and 106 Place SE. As for
the 3-inch pipe under the sidewalk, it appears to connect to the catch basin at the upstream end of the
swale. The downstream end of the swale empties into a culvert and catch basin and outfalls to a roadside
ditch, where all are located on the east side of 106'i' Place SE. This portion of the system drains to a 12-
inch concrete pipe (labeled as "36" on the Appendix B Map) connected to a catch basin located at the SE
comer of the intersection of SE 174111 Street and 106'" Place SE (labeled as "10" on the Appendix B Map).
From this point, stormwater joins the first leg of the downstream system along the south side of SE 174tb
Street, as described earlier. There were no observations of drainage or water quality issues during the
downstream analysis, except that some of the ditches within the right-of-way were observed to be
overgrown with vegetation and some litter had collected within them.
No surface water from adjacent roadways bordering the site was observed to enter the site, as it was
intercepted by sidewalk/curb and gutter conveying to catch basin and pipe system on Benson Drive SE
which directs flow around the site.
The proposed condition will include two buildings, parking areas and landscaping, as well as flow control
and water quality treatment facilities. Peak surface water runoff flow rates for the proposed condition are
anticipated to be reduced within in the downstream system as a result of the project.
9 Iun.20l3
4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
4.1 PART A -EXISTING SITE HYDROWGY
Refer to Section I, Figure 3, and Section 3 of this report, for the existing site conditions and hydrology.
Site soils are described in Section I and shown on Figure 4.
For this site, pre-developed hydrology is required to match forested site conditions; therefore, the entire
site was modeled as forest for the pre-developed condition. Till soils were used for all model runs
conducted for this report. Model inputs for land cover for both the pre-developed and proposed sites are
shown in Table 4. Hydrologic calculations are presented in Appendix A.
Table 4: KCRTS Model Inputs
Condition Impervious (acres) Pervious Total Percent
Bulldlng Pavement (acres) (acres) Impervioul
Existing 0.70 2.27 0.05 3.02 98%
Pre-Developed 0 0 3.02 (forest) 3.02 0%
Proposed 0.47 1.99 0.56 (landscaped) 3.02 82%
Flow rates for the existing, pre-developed/forested condition, and proposed/developed unmitigated
condition, and mitigated condition following detention/flow control measures are shown in Table 5.
Table 5: Peak Flow Rates
Flow Frequency Peak Flow Rates
Return Period Pre-developed Future
Existing Condition Forest Condition Unmitigated Mitigated 1
(cfs) (cfs) (cfs) (cfs)
2-y~ar 0.74 0.08 0.64 0.04
10-year 0.88 0.15 0.77 0.14
25-year 1.08 0.19 0.90 0.16
50-year 1.30 0.23 1.15 0.30
100-year 1.41 0.24 1.27 0.36 .. Note I. DIscharge flow rates from the detention system are WIthin 0.1 cfs of the predeve10ped forest
condition for the design flows ranging from 50% of the 2-year flow 10 the SO-year flow.
4.2 PART B -DEVELOPED SITE HYDROLOGY
Refer to Section 1 of this report and Figure 5 for the proposed/developed site conditions. Hydrology for
the developed site was analyzed using contributing drainage areas, soils and land cover types associated
with the proposed site conditions, see Section 4.1 and Tables 2 and 3 for land use and flow rates for the
proposed condition.
)0 June 2013
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KCRTS was used to evaluate the flow control facility (Section 4.4) and flow capacity requirements for
new storm drainage pipes (Section 5). See hydrologic calculations presented in Appendix A for model
results.
4.3 PART C -PERFORMANCE STANDARDS
Performance standards and goals for this project are based on the SWDM. which requires conveyance
system capacity standards, flow control facilities and BMPs, and basic water quality standards.
4.3.1 Area-Specific Flow Control Facility Standards
Flow Control Duration Standard, Forested Site Conditions apply to the site for flow controVdetention
facilities. Flow control BMP requirements are described in the response to Core Requirement #3 in
Section 2.
4.3.2 Conveyance System Capacity Standards
According to the SWDM Section 1.2.4.1, pipe system capacity standards are as follows:
• Pipe systems will be designed to convey and contain the 25-year peak flow, assuming developed
conditions for onsite tributary areas and existing conditions for offi;ite tributary areas.
• Pipe system stroctures may overtop for runoff events that exceed the 25-year design capacity,
provided that the overflow from a IOO-year event does not create or aggravate a severe flooding
problem or severe erosion problem. Overflow occurring onsite for runoff events up to and
including the IOO-year are required to discharge at the natural location for the project site.
Calculations are provided in Appendix A.
4.3.3 Area-Specific Water Quality Standards
In accordance with the SWDM Section 6.1.2, enhanced water quality standards apply. Enhanced basic
option 3 was selected for this project and includes a twO-facility treatment train comprised of a
StormFilter with ZPG followed by a StormFilter with CSF (see Table 6.l.2.A in the King County
SWDM, provided in Appendix A). Calculations for the StormFilter System are included in Appendix A.
4.3.4 Compensatory Storage Reqnirements
The project site is not located within the IOO-year floodplain; therefore, the project does not need to
comply with the compensatory storage requirements of FEMA.
4.3.5 Sonrce Control
See the response to Special Requirement #4 in Section 2.
4.3.6 on Control
Oil control requirements do not apply to this project.
II June 2013
4.4 PART D -FLOW CONTROL SYSTEM
Flow Control Facility
According to the City of Renton pre-application response dated September 13, 2012, the Flow Control
Duration Standard Matching Forested Site Conditions is required for this project site. Table 1.2.3.A of
the 2009 City of Renton SWDM Amendment states that if there is no problems identified downstream,
then apply the Flow Control Duration Standard whicb matches the flow duration of pre-developed rates
for forested (historic) site conditions over the range of flows extending from 50% of the 2-year up to the
full 50-year flow.
The KCRTS model was used to develop the size and volume of the detention facility. A detention pipe
system (Contech CMP detention system) is proposed for the flow control facility on private property. See
calculations and specifications provided in Appendix A. The dimensions are presented in Table 6.
Table 6: Flow Control Facility Summary
Required Detention (Flow Control) Volume 44 180 cf
Pipe Diameter 72 in (6 ft)
Sediment Stora~e 0.5 ft
Detention Denth 5ft
Orifice #1 Heigllt = 0 ft, Di .. -0.95 in
Orifice #2 Heigllt = 3.1 ft, Di •. -1.7 in
Riser Diameter 8in
Total Storage Provided 46,200 cf (Contech CMP or equivalent, see Al>Pendix A)
Spill Control (King County SWDM 2009, 4.2.1.1 Design Criteria). Where spill control is required as
specified in Section I.2.4.3.G, an allowable option is as follows:
• A tee section (see Figure 5.3.4.A) in or subsequent to the last catch basin or manhole that collects
runoff from non-roaf-top pollution-generating impervious surface prior to discharge from the site
or into an onsite natural drainage feature. The tee section typically provided in a wetvault or
detention facility may be used to meet the intent of this requirement. Unless otherwise specified,
the riser top of the tee section shall be at or above the headwater elevation for the lO-year design
flow and a minimum of 6 inches below the ceiling of the catch basin or manhole. The bottom end
of the tee section shall be as illustrated in Figure 5.3.4.A.
The outlet to the detention facility will have a riser overflow structure as detailed above. See Drawings.
Flow Control 8MPs
There are three areas onsite which would allow limited infiltration of stormwater. Two islands in the
middle of the site will have curb cuts and allow stormwater flow into the landscaped areas. Each island is
approximately 600 square feet.
There is a vegetated area along the south edge of the site whicb will be graded similar to a swale/rain
garden and will allow treatment and infiltration of stormwater. This area (within private property) is
approximately 5,800 square feet.
12 June 2013
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In all, approximately 7,000 square feet of pervious area will be graded and vegetated to promote
infiltration and treatment of stormwater. This area is approximately equivalent to the added impervious
area within the ROW. These types of Flow Control BMPs will supplement the proposed Flow Control
Facility and Water Quality Treatment BMPs required.
4.5 PARTE-WATERQUALITYSYSTEM
The project is a commercial site resulting in more than 5,000 square feet of pollution generating
impervious surface. Enhanced basic water quality treatment per section 1.8 of the SWDM as amended by
the City shall be provided.
Water quality design was completed in accordance with the SWDM Section 6.1.2, enhanced water quality
standards. Enhanced basic option 3 was selected for this project and includes a two-facility treatment
train comprised of a StormFilter with ZPG followed by a StormFilter with CSF (see Table 6.1.2.A in the
King County SWDM, provided in Appendix A). Calculations for the StormFilter System are included in
AppendixA.
Water quality treatment will be accomplished using a storm water filter subsequent to the detention
system. Proposed stormwater runoff will drain via gravity to a new detention system followed by water
quality treatment located near the southeast comer of the site. Following treatment, discharge will be
routed via gravity to the southeast comer of the site, where flow will discharge to the existing stormwater
system. The proposed locations of the detention and water quality systems are shown on the Project
Drawings.
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
5.1 EXISTING COLLECTION AND CONVEYANCE SYSTEM
The existing collection and conveyance system onsite is comprised of catch basins and storm drain lines
connected to the offsite drainage system, as described in Section 3. The existing onsite drainage system
will be demolished and a new system is planned for installation. The new system will connect to the
existing system with the majority of site flows draining to the southwest, as in the current condition.
5.2 PROPOSED COLLECTION AND CONVEYANCE SYSTEM
Site stormwater will be collected via catch basin inlets and drain via gravity to the detention pipe system
followed by water quality filtration system. HydrolOgy was completed for the developed site to determine
minimum pipe sizes for stormwater conveyance. Peak storm flows were estimated using the Rational
Method and pipes were sized using Flow Master (Bentley, 2009). The freeboard within each pipe was
calculated and the minimum 6 inches of freeboard requirement was met. See Appendix A for
calculations.
13 Jun.20l3
6.0 SPECIAL REPORTS AND STUDIES
Other than the geotechnical report developed for the site (Tenacon, 2012), no other reports or studies are
known.
7.0 OTHER PERMITS
Permits required for this project will be the standard pennits associated with construction of new
buildings, grading and drainage review. A general construction stormwater pennit will be needed
because the area to be disturbed is more than one acre.
8.0 CONSTRUCTION STORMW ATER POLLUTION PREVENTION
8.1 PART A -EROSION AND SEDIMENT CONTROL
A construction stormwater pollution prevention plan (CSWPPP) will be needed for the project. ESC
plans (included in the Figares section) have been prepared to address the minimum requirements during
construction, including temporary and permanent erosion controls.
Requirements for BMPs during construction conditions, as described in the City of Renton Amendments
to the SWDM Special Requirement #4 and the King County SPPM, are met and discussed in the
CSWPPP (URS, 2013).
8.1.1 Erosion and Sediment Control Measures
The following categories of the ESC measures, as detailed in the King County Erosion and Sediment
Control Standards (ESCS) and in compliance with the FOD requirements, will be incorporated into the
design and construction of the project:
• Clearing Limits -Clearing limits will be installed at the edges of all critical area buffers.
•
•
•
Cover Measures -Permanent cover measures in the form of placing topsoil, seeding, and
mulching will be provided to protect all areas to be converted to grass areas. Permanent
landscaped areas will receive topsoil, mulch, and permanent vegetation. Plastic sheeting may be
used to cover stockpiles and slopes during construction.
Perimeter Protection -Perimeter protection to filter sediment from sheetwash will be located
downslope of all disturbed areas and will be installed prior to upslope grading. Perimeter
protection includes measures such as silt fences, fiber rolls, sand/gravel barriers, brush or rock
f"tJ.ters and other methods. Perimeter protection will be provided by the combination of catch
basin inserts and fiber rolls that are downgradient of planned disturbed areas.
Traffic Area Stabilization -In genera\, unsurfaced entrances, roads, and parking areas used by
construction traffic will be stabilized to minimize erosion and tracking of sediment off site.
Stabilized construction entrances will be installed as the first step in clearing and grading, if
required. The eJtisting site is paved and the entrances to the site are paved
14 June 2013
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• Sediment Retention -Protection of catch basins will be conducted using catch basin inserts
installed at inlets that are likely to be impacted by sediment generated by the project. Sediment
retention facilities will be installed prior to grading of contributing area. Existing and newly
placed catch basin inserts will be placed during construction phasing to keep silt from entering
the storm drainage system. They will be inspected frequently and cleaned out or replaced as
needed to maintain their performance.
• Surface Water Collection -Surface water from distwbed areas will be intercepted by catch basins
with inserts. The sediment traps will be one of the first BMPs installed and once installed will be
used to provide treatment of construction stormwater. If required to meet surface water discharge
standards, stormwater collected in a catch basin will be pumped to a Baker Tank for settlement.
A sand filtration system may be used if needed to filter site stormwater prior to discharge. If the
detention system is used as a BMP during construction, it will be cleaned prior to commissioning.
• Dewatering Control -Excess water from excavations will be pumped as required to complete
construction. If dewatering occurs from areas where the water has come in contact with new
concrete, such as tanks, vaults, or foundations, the pH of the water must be monitored and must
be neutralized prior to discharge. Water from excavations will be monitored also for turbidity
and if turbidity exceeds surface water discharge standards, the water will be disposed of offsite or
treated prior to discharge to the storm drain.
• Dust Control -Preventative measures to minimize the wind transport of soil will be addressed by
the use of a vacuum sweeper. A water truck capable of spraying water may be used to control
dust.
8.1.2 ESC Performance and Compliance Provisions
The minimum performance required of the ESC will be identified in the CSWPPP and address the
following issues:
• ESC Performance -ESC measures will be inspected regularly and following storms to evaluate
their performance.
• Flexible Compliance -Following inspection, if a BMP is found to be ineffective in controlling
erosion or sediment, it will be replaced, repaired, and expanded as needed to effectively manage
erosion and sediment within the site.
• Roads and Utilities Compliance -Vehicles leaving the site will be clean and will not track soil or
debris onto public roads. Frequent sweeping of the project site will be needed.
• Alternative and Experimental Measures -the proposed work is fairly common as far as
construction in King County goes; therefore, no experimental measures are anticipated.
8.1.3 ESC Implementation Requirements
The project will identify, install, and maintain required ESC measures consistent with the following
requirements:
• TESCPlan.
• Wet Season Construction.
• Construction within Critical Area Buffers, if applicable.
• Maintenance.
15 June 2013
• Final Stabilization.
• Consideration for Other Required Permits.
8.2 PART B -SPILL PLAN DESIGN
The contractor's work will be performed in accordance with the requirements of a Spill Prevention Plan,
to be submitted by the contractor. Addressing spill prevention is also a requirement of the SWPPP.
9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
The Bond Quantity Worksheet is provided in Appendix C.
A Declaration of Covenant for the Privately Maintained Flow Control, Water Quality Treatment Facilities
and Flow Control BMPs is in process.
10.0 OPERATIONS AND MAINTENANCE MANUAL
Properly maintained drainage facilities, water quality treatment systems, and flow control BMPs are
important in prolonging the life of the facility as well as its effectiveness in managing stormwater and
providing treatment
Drainage facilities onsite will be privately maintained in accordance with SWDM Appendix A:
Maintenance Requirements for Flow Control, Conveyance and WQ Facilities and BMP Info Sheet 7 from
the SPPM in Appendix E (King County, 2009a). Drainage facilities will be inspected quarterly for
sediment and debris accumulation and overall condition. Based on the condition of the facility during the
quarterly inspection, repairs and cleaning will be conducted as needed. Inspection and cleaning will be
conducted annually.
Operation and maintenance requirements and observation instructions for the drainage facilities onsite are
presented on the following pages. These are referenced from SWDM Appendix A.
16 June 2013
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NO.3 -DETENTION TANKS AND VAULTS
Maintenance Defect or Problem Condttlona. Whln Maintenance Is NHdid Results ExpI'*<! wnen
component Maintenance Is Performed
Silll Trash and debris Any trash and debris which exceed 1 cubic. foot Trash and debris dAred from alt •.
per 1,000 Iqua" r.8I: (this fa about equ8l1O ",
amount of trash It WOUld taka ID till up ena
standard size otnee garbage can]. In general.
I there should be no visus! evld.nee of dumping.
NoxlO4JS weedt Any noxious or nuISance vegelation which may Noxious and nuisance vegetation
constltuta a hazard to County personnel or the rvrnovecl aCCOrding to applicable
pUblic:. ragulatjoos. No dang.,. of naxlous
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vegetation where County personna'
or tne pubic might normeOy be,
Contamlf'lllnis and Any lIVkI'ence or contaminants or pollution suth Mltarlals ramoved Ind disposed of
pOllution as 011. 988011ne. concrttllfurrles or paint according 10 applleabfe rvguIations.
Saurce control BMPllmplemented Jf
I approprfl.lII. No contamlnanll
present olller than • BlJIface on nlm.
Grasfgroundcover Grass or grtlUldcovar exceeds 18 fneha In Grass or gmundc:ovw mowed to a
height height no greatsr than 6 Inch ...
I Tank or VaUlt Trlllh and dabril Any trlsh and debris accumwatad In vaUlt or tank No Iruh or debris In vaUlt.
StorageAllI1l !indudea ftoatablas end non-floatable.).
Secllment Accumuleted ledlment depth exceeds 10% of the All sediment namovltd from storage
IlCCumulation dlametl/' or ttIe alonlge area for % length of .....
i storag. vaUlt or any poInt depth exceeds. 15% of
dlametar. Example: 72-1nch slorage tank would
requite tleanlng when sedIment ruc:h .. depth of
7 Inches fOr more than 1i length of tank.
I
Tank Structure PkJgged air vent Any blOckage of the vent. Tank or vault freely venll.
Tank bant out of Any part of IInklplpe I. bent out Of snape mare Tank repaired or nlpfaced to deslgn.
shape than 10% or Its daalgn IIhI!Ipe.
Gaps balwaan A g.p wider than %-Inch al tha )oInt Of any tank No water or sail entering tank
I sections. damaged sec:Uons 01' any evldenc::a or scil partlCles entering through joints Ql' walls.
JDlntl or cracks or the tank at a JOint or through a waJl.
taaT'lIn wall
Vault Structure Damage to waU, Cracks wider th8l"l ~d\, any evidence of soil Vault II sealed and abudul1lllly
frame. bottom, and/or entering Ihe IINcture through cradt. or quaUOed sound.
I top slab inspection personnel determines thai the vault I.
not struduraHy sound.
InIetIOutlet PIpes Sediment Sediment filling 20'1l! or IT'iOI1I gf the pipe. Inlet/outlet pipes dear at sadlm.nt.
accumulation
I Truh end debr1t Trash and debris accumulated In InlaUouUat No trash or debrla In plp8l.
pipes (Indudaa floatable. and non.ftoatable.).
lJamagltd Cradts WIder thin *Inch at the Joint of the No cracks more than y..tnch wide III
InletJoutlet pipes ar any evkl,nee Of soD entering the Jelnt of lI'Ie Inlelloutret pipe.
I at the joints of the Inlelloutlet pipe.
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2009 Surfa c:e Water DeslSU Mauual-Appendix A 1'92009
A-S
17 June 2013
APPE';UIX A ~L~NITh."-"(E REQUIREMENTS FLOW CO)[IROL. (0:-', "EY.-\J'(E. ",-,U WQ f.KIUTIES
NO.3 -DETENTION TANKS AND VAULTS
Maintenance D.fee'( or Problem Conditions When Malnt.nancels Needed Results Expected When I
Component Maintenance It ".r1anned
Access ManhOle COvermd nolln place Cover/lld Is missing or only partlaily In place. Manhole aecas, covered.
Any open manhole requires Immediate
maintenance. I
Locking mechanism Mechanism cannot ba opened by one Mechanism op.ns witt! proper tools,
nol · ... 'orldng m~lnlenance person with proper tools. Bolts
cenl10t be dated. Self-locklng ccverllid does not
work. I
Covert1ld dtmcult to One ma/nlenanct perton cannot remove Covar:lId can be removtel and
remolle covlr,1ld aft.r applying 80 Ibs of 11ft reinstalled by one malntenanee
person,
Ladder rungs unsafe Mlssfng rungs, mlsallgnmenl rust, or Cf1cks. Ladder meets deSign standards. I
AlIO'NS malntenanc. person sate
aecan.
Large access Damaged or cllnleutl Large Iccau doors or ptBtss cannot be Replat:e or repair eccess door so It
dOors/plate toopan opsnelVremovad using normal equipment. can apanod al designed. I
Gaps, doesn't t:over Larga access doors not nat anl1lOl' access Doors Close nat and C9vers access
completely opanlng not complehtly covarect. opening completel)!,
lifting Rings missing. Lifting rings nol capable otllftlng weight of door Lifting rings s.ufIIelanl to 11ft or I
rusted or ptata. remove door or plata.
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18 June 2013
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NO.5 -CATCH BASINS AND MANHOLES
Maintenance Defect. or Problem Condition When Mllntenance Is Neect.d
Component
strucIu .. Sediment Sectment exceeds 60% of the depth frgm the
bonom at lhe CIIIch basIn to the.nvert OIlhe
lowest ppe IOto or out of the catch basln or 18
with\II 8 Inches of the.nvert of the lowell pipe
into or out of the catch ban
Tmh and debris Trash or debris of mcQ than % cubic fool which
II located lmmedlBteJy In [ronl 01 the catch basin
opening or iI blocking ClpaQty a1 the catch bllin
by mO!O _ 10%.
Trash or debnlln Ihe catch bam that exceedt.
"I the depth from the bottDm of baaln to InWft""
Iowut p.peinto or oul of U. basin,
Dead .,1,... or vegeIaUon that colAd g8OI:nIte
odors thai could CIILIM camplalnla or dangerous
ga_ (e.g., _I. eo_ 01 gatbege .. c:aedlng 1 cubtc foot In -.
~tofra"," Comer of rr.me extends mora than % Inch palt
andlor top slab """ _Into the __ (If oppllcablo~
Tap slab haa hoi. larger than 2 IquarelnchH 01'
cnu:kl Wider than % inch.
Fnnni not SItting ftuah on top slab, I e.,
aepntlon of men than % inch of the rrame hm
the Iop_
Cracks in walts at Cradts wId .. 1han ~ ind1 and longer then 3 feet.
_m ony evidence of 001 po!1icIOI ontonng cold!
blstn through cracks. or maintenance pltson
j\Jdgoo l1l8I_ baoIn II _.
CIa"" wider thin Y.o Inch and Iongor _ 1 foot
at 1M JOInt d fIIflY InletlouUet ptpe or Iny avldence
01 001 pertid .. ontemg calch _through
crack •.
BeIIIemantl Catch bain h. HttIed more than 1 Inch or has
milllllgnmtnl _lad moro 1/1On 21_"" oIlllgnmenl.
Domogod pipe JOIn" Cnlck& wider than ~nch al the ,IoInl cllhe
1nfe1loUllat p.pes or MY evidence of 80iIlniering
the _ bealn lIthe joint 0/1/10 In_
1'1-
Contaminanll and My evidence of contamananll or pollution such
pollution .. 01, gasoline. conc::rete curriel or painl
1';8I/OUIIeI Pipe Sediment Sediment filling 20% or I110I1l 01 the pipe.
lICCUnWialion
T_ and d_ Trash and debrit accumulated m Inlatioullet
pipes (Inc/udos ttoa ........ lind """""""'_t.
Dam.~ Cracb wider than %-Inch at the joint of the
IrdetlouUet pfpea or any eYldence or son Inl8ring
81. the jointI Of the InletlouUet pipet.
2009 Surrllce Wall,. Deiign Munual-Appcmdix A
19
Results Expected WIlen
Maintenance Is Performed
Sump of catch baSin conlllina no
aechmant.
No Trash or debna blocking or
potentially bJockIng entrance to
catch te&in.
No trash or dall tn the cateh_ln.
No dead anlmall or """11atJDn
pl'BlMH1l WlHn catch basin.
No condition preaent which WtIlid
attract or support tie breeding of
inSecta or rodentiL
Frame is even with curb.
'top IIab ia tree of holes and cnICks.
Frame II sitting Itush an top lie.
Catch basin .... led and
atrucIuRilly lOund,
f!C Cf8Cb mora than ',.Inch wid. at
the Joint Of inlalloutlet pipe,
Bam ropIaced or _10 dll<gn
llandardl.
No cradtI mora than %-Inch wid, at
the joIn1 of lnletlouUeI plpaa.
Matarfals I'8I11OIt8d and chpoeed of
according 10 appOcabie regulations,
Source ""_ BMP, unpIomonlad. a_Ie. No """"""'-nto
prvsent olher' IhM • aurface 011 fiim
Inietloutlet pipes dear or sedlmenl
No nih or debna In Pipet,
No GIlIc:ka more than Xr-Inch wide at
the joint or the Inlet/outlet pipe.
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June 2013
,\PPE'\DlX" :.t,\I,\I1:~,\ ... n RL\1t'1RL\llS n, I'll)" l'O~ rROL.l'llSVrY,~'\n. ,\,\1> \\\1 rAULI m:s
NO.5 -CATCH BASINS AND MANHOLES
Maintenance Defect or Problem Condition WMn Mllntenenc:e 1$ Needed Rosul1s Expected When
Compo .. nt Molntenan .. l. Performed
Me1aIGtates Unsafe grato opening Grate 'Mth opening wider than 7;, Inch. Grate opening meets design
lcatch Basins) atandanlo. I
Trash and debris Trash and' debns thai is bfoddng more lhan 20% Grate tree of lrash .,d debris.
of grate IUrface. footnoto to g_ines fat eli_I
Damaged or ml8Iing Grate mlomg Of broken membor(sl 01Il10 gI8Ie. Grate Is In place and meets design
Any open .tructure requires &qent _"'" I
maintenance.
Manhole CoyarlUd CoYerIUd' IlOf: In place Covat~1d I. milling Of only partiely In place. Covatlld proIec:Is opening 10
Any __ -,.quI ... urgent _roo
maintenance. I
Lacking madlanlem Mechantlm cannot b. opened by one Mechanism open. wtth proper looIa.
Not WarlcJng maintenance peraon with prop8f IooItL Bolla
Clrmt be aeated. SeIf-lodling covetllid does not
work. I
CovotIild dlfllcUllO One maintenance per1lOO cannot remove CoverJ\ld can be removed and
R ...... _ after applying DO ... of 11ft. rainsllllled by one maintenance
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2tl09 Surf-.:c ,,"oleer Dl::ooign Manual-Appc1ldix A
A·IO I
20 Iune2013
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APPf,DlX A \L\['I,'T",,\~U REQl"JRBflXfS FUR F1 ow (,()" lllOL CO~'VEYA~lE A~D WQ FAllI.ITI[~
NO.6 -CONVEYANCE PIPES AND DITCHES
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Maintenance Defect « Problem Cancltkms When MaIntenance Is Needed Results Elcpocted When
Component Malntananc.1s Performed
Plpee Sodiment&_ Aoc;umuIated lildimant or debris that e.ceedl water -.1IueIy "'1019> _.
accumulation 20% of Ihe diameter of Ih, pipe.
I Va;e_ta V_lia_ that roduco !rae ........... ~ WI"" -. _y through ppe •.
WIlIer through pipes.
Cont.mmBnfl; and Any eYldence at contaminants or pQlUban 8UCh Matena. '"""""Id and clilposed of
poIubon .. of!. gnoIIna, CXIRC2ete slumas or paint IIC:«>IdIng '" appIIca~e "'II~abonl
-.. contra! BMPslmpiementad.
I 8PPfOPnala, No contaminants
preeeni other than 8 turface all film
Damage"'-Protactlve coating II damaged' nasl or COIT08iOn Pipe r.paIrod 01' rapiaced.
~ or cotI'OIion Is wukerlng tha ""_ integrity of OIly part 0/
I pipe.
Damaged Any dent tNIt deaea_1he crvaa HCtlon area of Pipe ,"pend or replaced.
pipe by more thon 20'1& 01' 10 determined '" ""'"
weakened ...... rallntegrlty of the pipe.
I 01_ Trash and dabrfa Tra'" ond debris """'.1 cubic loot per 1.000 T_ and dlbr!a _ fn>m
aq .... fHl~_ and~. -Sedment Accumulated uclmenllhet 8XCBedll2Q% of Ihe OilCh cfeanD'fUlhld of all sediment
ICClJIIWIation doIIgn depOt 8I1d debrte 10 !hat it metd1n deslgl.
I ---AnI nox£oua or nuisance \feSIeIIlD1 which may
_ .... nui ___
consUtute • hazard 10 CoU1ty personnel or the ,...."ad IICCOIdIng '" appl_
pubic. regufationa. No dang .. of noxious _lion who .. County _nnel
01' UMI public mlg~ normally be.
I CodaminIInta and My evidenca d contamlnanta at poIutfon IUch Ma/e!ialo _ and disposed 01 -.. 011. galOflne. eoncrate slurries or paint _Ing '" applicable raaUaliOnl .
SOurce corlrd BMP_lmpIemented d
approprlatll. No canlamlnantl
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present other Ihan ,surface oil film.
Vagotalian Vegelatton that reducaI fi'ee moYem8f\1 r4 water Water now. holy through_.
through_
e ...... damag.1O Ar1y eroaIon ob.wd 00 a dhch lIope. Slopes 1111 noIltOding.
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Rodt 11'*'0 out of One layer or Ieee of rock .Xil" above native .::III Replace racIca to doogn _ORII.
place 01' m1_g (~ area 5 squlU8 feet or rnor.. any upoI8d native
Applicable) .ell.
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2009 Surface Wall.T l.k:sip \llullll-AppendiX /\ 11)2009
A-II
21 June 2013
NO. 11 -GROUNDS (LANDSCAPING) I
MIIlntenanee Defect or Problem Conditions When ... nt.nance , .. N ...... Rosulls Expoctod ""on
Componen' Mllntenanee Is. PerfonMd
Silo T nIIh or litter My trIIh and debris whICh exceed 1 aJbIc fo3t Trush and dItIrI, deated flam site.
por 1,000 equant roe, (this II _, oquallll tho I
..".,.,.. or tralh il would lake tD fBI up one
standen:! aIze otnca gIII'NQe can}_ In ;enell!.
lhenJ IhouIcI be no vllual aYICIenoe 01 dumping
Noxious weeds My noxious 01' nBunce vegetallon wtlaCh may NaxlaUl and nutunc. vegetallon
conatlluta • hIZIrd 10 County peIIOMIl or the -_nalll~l. I
pIJbIio __ '.No_oInoxIouI
vegeCation whar. County peraomel
or tho public might nonnatIy be.
Contamlnonta and /In • ..-01 contaminants or pollution ouch MItInaIt remtMKland cI~ of I
paIution 81 oM, gasoline. concrete lIuniel or pUt. IICCCIdfng 10 applcable regullbona.
-.. conIrOI BMPsimplemo_ W
oppIOpIioto. No_nora prauN __ ._oiInlm.
Gl1IOOIgrourodcovor Gr ... orgroundccYer«m:aeds 18 inCh. In Grall or groundcoYet mowed 10 • I
hoGht height '" graa10r tho" 8 _.
Tra.and Shnm. HozIIR1 Any he or 11mb or. hili identified .. having.
pot.enUaI to fall and C8UH propllty damege or
It'nItIn hl.IrMn life. A haard tree JMnUfted by
No __ on racily. I
• q...nfted .-borlst must be twmewed .. 1OOn
•• pouIbIe.
Domeged Lila « p .... t1 trHI or Ihrubl that &nil Ipllt« T ... and IhrulMi wtth , ... than ft
broken whd1 Bftect men It'IIn 2SCKr of the toIIIl 01 __ wlth.~ or broken
Mage at III rae or Ihrub. limbo. i
TrMI 01' IhrWI that haVe been bIo'M'I down Dr No blown dawn vegetellon eN'
knocIctd OYer. ICnocked ovw vegelatiOl't Tf88I or _ he 0I1rjoM1I.
TnIeo Of s.Nbo ""'''' .. not _uJy Trae or IIwb in pIac8.,d -""<1" __ -, __ • _uatel. MlPporIed; _ ..
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dI __ ramovod.
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22 June 2013
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NO. 21 -STORMFIL TER (CARTRIDGE TYPE)
MalntenanCI D.fael or Probl.m ConditIon wnen Maln"nance Is NHdtd Results l.xFH'ctad When
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Component Maintenance Is Plr1'ormad
S~. Trash and debris Ar'foj Uasl'! or debris which impairs 11'1. function or Trash and debn' removed from
the facility. facility.
Contaminants and Any evidence of conlamlnenl, or pollution such Met.rlals removed and disposed of
I pOllution liS oils. gasoline, concrete Slurries or paint. according to applicable regUlations.
Source control BMPs imp;.mented If
approprlate. No contaminants
present ottler than a surfatt 01 fUm.
Lift cycle System ha, nol bt.n inspected fer thr.e years. FacUlty Is re-lnlpKted and any
I n •• ded maIntenance ~rfOrmed
Vault Treatment Sldmant on vault Grealer than 2, IncheS of se<limenl. Vault [s free of sediment
Ar •• ,-
I Sltdlmenl on top or Greater tnan l,o] Inch of sediment. Vault Is tree of sediment
cartrldges
MUltiple scum IInti Thlct or mUltiple scum I1ne5 above top of Caus. of p;ugglng corree1ed,
above top of cartridges. Probably due to plugged canisters or canisters replae.o If necessary.
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cartridges underdraln manifold,
Vault Structur, Damage to wall. Crack. wldar thar. ~nd'l and any .lIidenee of VaUlt replaced or repaired to design
Frame. Bottom. endror soli porllel .. tnlerlng the structure through the speenteallons.
Top Slab cracil:s. or quatlnllCllnspeellon personnel
determines the vault Is not structurally sound,
I eam .. damaged eem., corrading. creeklng warping. and/or Repair or replaet bam" to
shOwing signs c1'1ai!ure as dtltnnlned by speelflcatlon.
maintenance/Inspection person.
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Filter Media Slandlng wattt In 9 Inch. or gr.ater of .tauc water In the vaUlt for No standing ..... ater In vault 24 hours
vault more (han 24 "'ours follOWing a rain evenl end/or ener IS rain event
ov.r1!O'.oo' OCcurs hquently. pn:lbably due to
plugged l'1lt.r medIa. underoraln or outle4 pip.
Short drCUltlng Flows do not proper1y enter filler e.t11r1dges. Flo ..... s go through filter medle.
I Underdrains and SedlmenVdebris Und.td~n. or cl.an-cut. pertiafly plugged or Undardralns and dean-oulS lrae of
Clean-Outs tilled with sediment andior debfjs. sediment and debris.
rnlaUOutl.t Plpa SedIment Sediment ruling 20% or more 0' ttle pipe. Inlet/outlet pipes clear of sediment.
accumulation
I Trash and dabrl' Trash and dabrlslccumuJatld In Inllt/oullet No trash or debris In p!pts.
Pipes (Inc:ludes tloalllbiis and non-noatables).
Camaged Cracks wider thin *Inch al the JOInt or the No craCk, more than V."'nch wide at
I Inlat/outlet pipes or Iny eVldenca of solt antertng the Joint of tn; Inlet/oullet pipe.
at tn. JOints of theln/et/outlet pIpes.
Aetess ManhOle Coverllld not In plaea Covernld Is miSSing or Only partially In plac •. Manhole aeCH' !!Overed.
My optn manhole requlrt, lmmedlat.
maintenance.
I L.ocklng m.ttlanlsm Mechanism cannot bill opened by on. Mechanism opens with proper tools.
nol working maIntenance person with proper 100is. 80lts
cannot be seated. Self-loc.klng cOYlrtlld does nol
work.
CO'Jlrllld dtmcult to One maintenance plrson cannot remove Coyerllld can bl removed and
remove coverltld after appylng SO Ibs or 11ft. relnslaUed by one malnllnance
person.
Ladder rungs unsafe Mining rungs. ml"llgnment. rust, or Clacks. Ladder ml.ta deSign ,tsndards.
AllOw' malntenancl parson safe
access.
largeacee" Oamaged or dffficUit Largt access doon or pratl' cannot be Replica or repalf accass door so It
doOrs/plate to opan opened/remol/.d using normal equlpmenl can opIned es designed.
1':9 :W09 2009 Swtace WaTer Design Manual-Appendix A
A·30
23 June 2013
APPENDIX A ~!ANIDI&,CE REQUJRDm.-rs FOR now C<NrROL CONVEYA.'1CE.~"D WQ FACll.ITIES .
NO. 21 -STORMFILTER (CARTRIDGE TYPE) I
Mafntenance Cefect or Problem Condition When Maintenance 1& Need,d ..... ulta EXpICtlid When
Companant "'alnlenancI 1. tt.rforrned
Gaps, doesn't cover L.arge aeeess doors nol1'fat and/or IIccan Doors Close flat .-ld Covar aecau
complel.l~ opening noI completely covered. OPining completely. I
umng Rings ml .. ,ng. LIftI"g rings nol c.lpebla of lifting w.lght of door UftIng rings sul'ftclent '" un or
",sted or plille. remove door or plate.
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24 June 2013
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11.0 REFERENCES
City ofRenlon. Amendments to the King County Surface Water Design Manual. February 2010.
King County, Department of Natural Resources. King County, Washington. King County Stormwater
Pollution Prevention Manual (SPPM). January 2009a.
King County, Department of Natural Resources. King County, Washington. Surface Water Design
Manual (SWDM). January 2009b.
King County, Department of Natural Resources. King County, Washington. King County Runoff Time
Series(KCRTS) Model. January 2006.
Terracon Consultants, Inc. Geotechnical Engineering Report. Proposed Pharmacy #69744 -Carr Road
& Benson Drive South, Renton, Washington. October 2012.
USDA Natural Resources Conservation Service. Soil Survey King County Area, Washington. July 2012.
25 Juno 2013
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KI,<G COC:-ITY. WASHll'GTO'<. Sl"RFACE WATER DESIG,< MA"'e.~L
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 1 PROJECT OWNER AND
PROJECT ENGINEER
Project Owner The Velmeir Companies
Phone Wayne Shores (248)318-0593
Address 5757 West Maple Rd.
West Bloomfield, M I 48322
Project Engineer John VerPlank
Company URS Corporation
Phon. -'616)574-8500
Port 3 TYPE OF PERMIT APPLICATION
[J Landuse Servic"
Subdivison / Short SUbd. I UPO
Ii) Building Services
MlF / Commerical / SFR
iii Clearing end Grading
[J Right-of-Way Use
[J Other
Port 5 PLAN AND REPORT INFORMATION
Technical Information Ropon
Type of Drainage Review @/ Targeled /
(cirde): Large SHe
Dale (induda revision
dates):
Date of Finel:
Part e ADJUSTMENT APPROVALS
Part 2 PROJECT LOCATION AND
DESCRIPTION
PrOject Nome Velmeir Retail Pharmacy
ODES Permit # __ ~= ____ _
Location Township 23N
Range _~05:-,E=--__
Section =-:::2:-9==--=-:-:
SHe Addre.. 10660 SE 176th Sl Renton
Part 4 OTHER REVIEWS AND PERMITS
[J OFWHPA
[J COE404
[J DOE Dam Safety
[J FEMA Floodplain
[J COE W.ij.nds
[J Other
[J Shoreline
Management
[J Structurel
RockeryNauIV __
[J ESA Section 7
Site Improvement Plan (Engr. Plan.)
Type (circle one): Full / Modified /
Small Srte
Data (include revtsion
dates):
Date of Final:
Type (circle one): Siandard / Complex I Praapplicalion I Exparimental I Blanket
Description: (indude conditions in TIR Section 2)
Date of ADoroval:
2009 Surface Water De$ign Manual
I
I 92009
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KDIG conny. WASHIJ';GTOl<. SL'RFACE WATER DESIG:-< MA:-<l'AL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 11 DRAINAGE DESIGN LlMITA nONS
REFERENCE LIMITATION! SITE CONSTRAINT
IX) Core 2 -0fIs~. Analysis
a Sensj~velQmi&l1 6[!ms
iii §Ef&
[J Other
[J
[J Additional Sheet. AHached
(include faciily summary sheet)
Type: Major I Minor I Exemption ~
lOG-year ease Flood Elevation (or range): ____ _
Datum:
(comm.lindustriollanduso ) Describe any structural control&:
2009 Sluface Water Design Manual
3
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K!:-<G COC'iTY, WASHI:-<GTO:-<, Sl"RFACE WATER DESIG:-< ~!A:-<L'AL
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Oil Control High-use Site: YeslQ!V
Trealment BMP:
Maintenance Agreement Yes ! No
with whom?
Other Dralnaae Structures
Describe:
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION AFTER CONSTRUCTION
CJ Clearing Umits Il!l StabBoza Exposod Surface.
Il!I Cover Measures Iiil Remove and Rastore Temporary ESC Facil~ie.
Il!l Perimoter Protection I!I Clean and Remove All Sit and Debris, Ensure
I!I Traffic Ana. Stabilization Operation of Permanent Facilities
Il!I Sodlment Retention CJ Flag Limits of SAO and open spac'
CJ Surfaea Water Collection
preservation areas
CJ Other CJ Dewatering Control
[ill Dust Control
CJ Flow Control
Part 14 STORMWATER FACILITY DESCRIPTIONS (Nato: Include Facility Summary and Sketch)
Flow Control Type/Description Wate, Quality TYPo/Doscrilllion
III Dotention CJ Biofiltration
CJ Infiltration CJ Wotpool
CJ Regional Facility CJ Madia Fikr.tion
CJ Shared Facility CJ Oil Control
Iiil Flow Control CJ Spill Control
BMPs CJ Flow Control BMPs CJ Other tiiJ Other Conlech Storm Filter (or Eq I valent)
2009 Surface Waler Desipl Manual 1'9'~009
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KI:oIO COl.""T\". WASHINGTON. Sl'RFACE \VATER DESIG:oI MA:oIl'A.t
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Pert15 EASEMENTSITRACTS Pert1. STRUCTURAL ANALYSIS
tJ DraInage Ea.ment tJ C.llln PI ... Vault
tJ Covenant tJ ReIUoIng Wall
tJ _ Growth P_ Cov • ...., tJ Roekery > 4' High
tJTrad tJ SlrUcNnII on SIMp Slope
tJ Other tJ 0 .....
PertH SIGNATURE OF PROFESSIONAL ENGINEER
I, or • civil eng",", under my IUporviolon, ha .. '"_ the lite. Actual lite ccnd'lIiano .. o .... rved w ...
incorpo_lnID thi •. WOrk_I.~nd the,1IIached Tochnlcallnforrnation Roport. To tho belt of my
knowledgo tho Inforl)l8lion fO"lded ~: ~"";'''''' , I
0'.. /,t , £I/dA 8 I J -3 J::!.
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[-FIGURE 3 Existing Site Conditions IlL] Parcels
Structure
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107 Foot
Information Technology -GIS
RentonMapSupporl@Rentonwa,gov
This map Is a user generated static output from an Internet mapping site and
Is forrafer&nC8 only. Data layers that BPpearon this map mayor may not be
accurate, curren~ or otherwise reliable.
1210812012 THIS MAP IS NOT TO BE USED FOR NAVIGATION
• catcnbasIr1 -Type 1
• Catd'IbuITI. Type1L
• CGncretalCurb Inl81-Type 4
• Drop InllII
Catchbuln -Type 2 MH
• ...",. .....
UtlltyVauH
.I Urimawn Structure
Cllk:hbuln· Type 1
Calchballn· Type11.
CcncreteICulb Inlet -Type ..
Drop Inlat
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II Access Rlur
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• CIIMIIlCl~
• Other
.I' Unknowtl Sln.Icture
C8ld1twln· Type 1
Caldlbuln -Type 2MH
Control Structure
00 Renton MllirtlllinlKl
• Prrvately Malntamad
.. Pump station
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.. Renton Maintained OUtraM
" PrfYlltllIy Maintained OUtfall
Alling ......
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FIGURE 4: SOILS
" <> r···· ..
'it
Map Scale: 1:1.120 If pmled on Asila (as II 11") shoot.
~ N A
~~~=:;~ __ ~~====::"M8ters o 10 ~ ~ 00 ,!-_~::::;:;;"'~ __ ;;"""!'!;:;=::::;:;;;"'==:?Fo.t
o 40 BO 160 240
USDA Natural Rosoult:e.
--Conservation Service
Web Soil Survey
2011 ~1~~III$."""",a(Ou
121812012
Page 1 of 3
47" 26' 48"
4r 26' 41"
--------- -- --.. .. Soli Map-Klng County Area, Washington
FIGURE 4: SOILS
MAP LEGEND MAP INFORMATION
...... 0I1 ...... 1(A011
Area of Interest (AOI)
Sollo
Soil Map Units
Special Point F •• tu ....
C!J Blowout
1&1 Borrow Pit
liE Clay Spot
• Closed DepressIon
X Gravel Ph
... Gravelly Spot
0 landfill
A. lava Flow
.... Marsh or swamp
~ Mine or Quarry
\I Miscellaneous Water
® Parannlal Water
v Rock Outcrop
+ SeRne Spot
.. Sandy Spot
..... BeYerely Eroded Spot
~ Sinkhole
J> SIld. or Sip
~ SodlcSpol
II Spoil Area
I) Stony Spot
USDA Natural Resaun:es
... Cona8rvatlon Service
(I) Very SlCny Spol , Wet Spol
... 0Ih ...
Spacial Line F •• turn
"'-Gully
.' . Short steep Slope
~-OIher
Polldcal F .. tu,..
• Cities
Water Features
Streams and Canals
r,..,.portatlon
+H-Rails -'nterstate HIghways
/V US Routes
Major Roads
"'" local Roads
Map Scal.: 1:1,120 If printed on A size (8.5" • 11") sheet.
The soU surveys that comprise your ADI were mapped at 1 :24,000.
Warning: Soli Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
mlsund""""ndlng of !he eJetan of mapping and accuracy of soli line
placement. The maps do not show the small areas of contrasting
solis that could have been shown at a more detailed scale.
L--._~
Please rely on the bar scale on each map sheet for accurate map
measurements.
50urQI of Map: Natural Resources Conservation Service
Web 5011 Survey URL: h8p~lwebsoll.urvey.nrcs.usde.gov
Coordinate System: UTM Zonel0N NAD83
This product I. generated from the USDA-NRCS certified data as of
the ve",'on date(s) listed below.
Soli Survey Area: King County Area, Washington
Survey Area Data: V.",'oo 7, Jul2, 2012
Date(s) aerial Images were pho1ographed: 7124/2008
The ortflophoto or other base map on which the soUIJnes were
compiled and dlglUzod probably differs from the background
Imagery displayed on these maps. As a result, some moor shifting
of map unit boundaries may be evident.
Web Soli Survey
NaUonal Coopora8ve Soli Survey
12/8/2012
Page 2 of3
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Soil Ma~Klng County Area. Washington FIGURE 4: SOILS
Map Unit Legend
King County Are .. Washington (WA633)
Mop UnH Symbol I Map Unit Name 1 Ac ..... In AOI .1
AgC
ArnC
i--_____ ~
; Totels for Are. of Intarest
NatUnll~urces
Conservation Service
Alderwood gravelly sandy loam, 6 to 15
percent slopes
Arents. Alderwood material. 6 to 15 percent.
slopes
.. ..................•.• ._ ................. -
Web Soli Survey
National Cooperative Soil Survey
0.2,
6.1
8.3
Pare.nt of AOt
3.0%
97.0%
100.0% .
121812012
Page 3 of3
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A I'a!lIOII GI' TH: BECOCII N, NTOIIMtI' Z3H:l1lH JII.'a 5Wf, aTTCFIIM'OI. u«I c:cum, II'A!N«1IllI
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DURING CONSTR~CllON. ~ CONTECH
REPRESENTATIVE MUST BE ON-SITE AND
PRO'o'lDE A f't<AL iNSPECTION OF THE
DETENTION SYSTEM AND fiLTRATION UNITS
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CH2 -CB#6 PROFIl!'
SIQtion
0+ 0 1+00 2+00 2+
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C87TO DETENTION BASIN
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END semON· MHU PROfilE
Slot;."
_ .. _ . . ----
hOO
END SECTION. cans PROFILE
.1/OOI'J
CJ.7
APPENDlXA
DESIGN STORMW ATER CALCULATIONS
Appendix A -Calculations
1. Areas and Land Use
2. Peak Flows
3. Detention/Flow Control
4. Conveyance
5. Water Quality
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SECTION A-l
AREAS & LAND USE
ExisUnl Sit 1
Pavement:
BuUdtnr-
Landscape.
Totill
Developed Site
Pharmacy
Pawment=
8ulldlnr=
Griilss/landscape=
Total
FutM" ftU FAPd
Pavement:
Bulldlng=
Grass/landStape-
Total
Tpt.lsib! 'private pmp'rtyl
Pavement=
Bulldln ..
Grau/landstilpea
!!IIY!
New Impervious
Replaced ImpeNiOlls
Tgbllllll iI.crill.1 BQYll
Pavl!!ment'"
Buildlnr-
Grass/llndscape:
Areahfl
88,112 ,I
30,600 ,I
2,000 ,I
120,712 'f
Are.lsf)
45,000 ,I
16,270 ,I
11,630 sf
72,900 sf
30,924 'f
4,300 sf
12,620 sf
47,844 sf
120.744 sf
75.924 sf
20,510 sf
24,250 sf
nO,744 sf
6640 sf
4USsf
108&5 sf
16,789 " 20,570 " 24/250 sf
131,109 "
Arei (ac) Impervious Area
2.02 ae
2.73 ac:
0.70 Ie
0.05 ae 0,05 ie
2.n ae 2.nae
Area lacl
un at
0.37 ilt
0.27 ae
1.67 ae
0.71 ae
0,10 It
0,29 ilt
1.10 ill:
2.17 Ie:
Impervious 96,494 "
Pervious 24,250 sf
12D.744 sf
0.15 ae
0.10 ae
0.25 Ie
Impervious 107,359 ,I
Pervious 24,250 sf
131,609 If
2.22 Ie
0.56 ae
2.77 Ie
2030 sf
4610 sf
4225 sf
2.46 ae
0.56 Ie
3.02 Ie
98.3%
1.7%
100.0"
8'" , ...
sidewalk on Benson
road Ind sldeWJlk on 174th
replaced impl!rvlou5 on 174th
82"
18"
100"
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SECTION A-2
PEAK FLOWS
Predeveloped forest condition -peak flows
till solis
forest·3.01acres
timestep = 1 hour
Flow Frequency Analysis
Time Series File:cvs3-pre.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates---
Flow Rate Rank Time of Peak
ICFS)
0.190 2 2/09/01 18,00
0.052 7 1/06/02 3,00
O.HO 4 2/28/03 3,00
0.005 8 3/24/04 20,00
0.084 6 1/05/05 8,00
0.146 3 1/18/06 21,00
0.123 5 11/24/06 4,00
0.243 1 1/09/08 9,00
Computed Peaks
Developed site condition -peak flows
till soil,
impervlou, =2.45 at
grass. 0.56 ac
timestl!p = 1 hour
Flow Frequency Analysis
Time Series FiletcVs3-dev.tsf
Project Location:Sea-Tac
---Annual Peak Flow Rates---
Flow Rate Rank Time of Peak
ICFS)
0.644 6 2/09/01 2,00
0.549 8 1/05/02 16,00
0.773 3 12/08/02 18,00
0.621 7 8/26/04 2,00
0.741 4 10/28/04 16,00
0.686 5 1/18/06 16,00
0.904 2 10/26/06 0,00
1.27 1 1/09/08 6,00
Computed Peake
-----Flow Frequency Analysis-------
--Peaks Rank Return Prob
ICFS) Period
0.243 1 100.00 0.990
0.190 2 25.00 0.960
0.146 3 10.00 0.900
0.140 4 5.00 0.800
0.123 5 3.00 0.667
0.084 6 2.00 0.500
0.052 7 1.30 0.231
0.005 8 1.10 0.091
0.225 50.00 0.980
-----Flow Frequency Analysis-------
-Peaks Rank Return Prob
(CFS) Period
1.27 1 100.00 0.990
0.904 2 25.00 0.960
0.773 3 10.00 0.900
0.741 4 5.00 0.800
0.686 5 3.00 0.667
0.644 6 2.00 0.500
0.621 7 1.30 0.231
0.549 8 1.10 0.091
1.15 50.00 0.980
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SECTION A-3
DETENTION I FLOW CONTROL
Input Parameters:
Flow Control Duration Standard which matches the flow duration of pre-developed rates for forested (historic)
site conditions over the range of flows extending from 50% of the 2-year up to the full 50-year flow.
2 year
50% of 2 year
50 year
Initial inputs for detention calculation
0.08 cfs
0.04 cts
0.23 cfs
orifice flow rate = 4/3·lower target
effective storage depth
height of orifice =3/4·eff depth
Target Duration
0.05 cts
5 7ft
4 5.3 ft
Set the First Interval cutoff equal to 50 percent of 2-year =
# of Cutoffs
Set the Interval Size equal to (50-year flow minus 50% 2-year) / (# Cutoffs minu
See attached model output
0,04 cts
17
0.012 cts
SECTION A-3: DETENTION/FLOW CONTROL FACILITY SIZING
Retention/Detention Facility
Type of Facility: Detention Vault
Facility Length: 94.00 ft
Facility Width: 94.00 ft
Facility Area: 8836. sq. ft
Effective Storage Depth: 5.00 ft
Stage 0 Elevation: 0.00 ft
Storage Volume: 44180. cu. ft
Riser Head: 5.00 ft
Riser Diameter: 4.00 inches
Number of orifices: 2
Full Head Pipe
Orifice # Height
(ft)
0.00
3.10
Diameter Discharge Diameter
1
2
Top Notch Weir:
Outflow Rating Curve:
Stage Elevation
(in)
0.95
1. 70
None
None
Storage
(CFS) (in)
0.055
0.108 4.0
Discharge
(ft) (ft) (cu. ft) (ac-ft) (cfs)
0.00 0.00 O. 0.000 0.000
0.01 0.01 88. 0.002 0.002
0.02 0.02 177 . 0.004 0.003
0.03 0.03 265. 0.006 0.004
0.04 0.04 353. 0.008 0.005
0.05 0.05 442. 0.010 0.005
0.06 0.06 530. 0.012 0.006
0.07 0.07 619. 0.014 0.006
0.08 0.08 707. 0.016 0.007
0.09 0.09 795. 0.018 0.007
0.19 0.19 1679. 0.039 O. all
0.29 0.29 2562. 0.059 0.013
0.39 0.39 3446. 0.079 0.015
0.49 0.49 4330. 0.099 0.017
0.59 0.59 5213. 0.120 0.019
0.69 0.69 6097. 0.140 0.020
0.79 0.79 6980. 0.160 0.022
0.89 0.89 7864. 0.181 0.023
0.99 0.99 8748. 0.201 0.024
1.09 1.09 9631. 0.221 0.026
1.19 1.19 10515. 0.241 0.027
1.29 1.29 11398. 0.262 0.028
1.39 1. 39 12282. 0.282 0.029
1.49 1.49 13166. 0.302 0.030
1.59 1.59 14049. 0.323 0.031
1. 69 1. 69 14933. 0.343 0.032
1. 79 1. 79 15816. 0.363 0.033
1.89 1.89 16700. 0.383 0.034
1. 99 1. 99 17584. 0.404 0.035
Percolation
(cfs)
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
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r. 2.09 2.09 18467. 0.424 0.035 0.00
2.19 2.19 1935l. 0.444 0.036 0.00
[ 2.29 2.29 20234. 0.465 0.037 0.00
2.39 2.39 21118. 0.485 0.038 0.00
2.49 2.49 22002. 0.505 0.039 0.00
~ 2.59 2.59 22885. 0.525 0.039 0.00
2.69 2.69 23769. 0.546 0.040 0.00
2.79 2.79 24652. 0.566 0.041 0.00
2.89 2.89 25536. 0.586 0.042 0.00
[: 2.99 2.99 26420. 0.607 0.042 0.00
3.09 3.09 27303. 0.627 0.043 0.00
3.10 3.10 27392. 0.629 0.043 0.00
~ 3.12 3.12 27568. 0.633 0.044 0.00
3.14 3.14 27745. 0.637 0.046 0.00
3.15 3.15 27833. 0.639 0.049 0.00
~ 3.17 3.17 28010. 0.643 0.053 0.00
3.19 3.19 28187. 0.647 0.059 0.00
3.21 3.21 28364. 0.651 0.065 0.00
3.22 3.22 28452. 0.653 0.072 0.00
~ 3.24 3.24 28629. 0.657 0.074 0.00
3.26 3.26 28805. 0.661 0.075 0.00
3.36 3.36 29689. 0.682 0.085 0.00
( 3.46 3.46 30573. 0.702 0.093 0.00
3.56 3.56 31456. 0.722 0.099 0.00
3.66 3.66 32340. 0.742 0.105 0.00
3.76 3.76 33223. 0.763 0.111 0.00
[ 3.86 3.86 34107. 0.783 0.116 0.00
3.96 3.96 34991. 0.803 0.121 0.00
4.06 4.06 35874. 0.824 0.126 0.00
[ 4.16 4.16 36758. 0.844 0.131 0.00
4.26 4.26 3764l. 0.864 0.135 0.00
4.36 4.36 38525. 0.884 0.139 0.00
E
4.46 4.46 39409. 0.905 0.143 0.00
4.56 4.56 40292. 0.925 0.147 0.00
4.66 4.66 41176. 0.945 0.151 0.00
4.76 4.76 42059. 0.966 0.154 0.00
~ 4.86 4.86 42943. 0.986 0.158 0.00
4.96 4.96 43827. 1.006 0.161 0.00
5.00 5.00 44180. 1. 014 0.163 0.00
~ 5.10 5.10 45064. 1. 035 0.269 0.00
5.20 5.20 45947. 1.055 0.357 0.00
5.30 5.30 46831. 1.075 0.403 0.00
5.40 5.40 47714. 1.095 0.442 0.00
~ 5.50 5.50 48598. 1.116 0.476 0.00
5.60 5.60 49482. 1.136 0.507 0.00
5.70 5.70 50365. 1.156 0.536 0.00
m 5.80 5.80 51249. 1.177 0.564 0.00
5.90 5.90 52132. 1.197 0.589 0.00
6.00 6.00 53016. 1.217 0.614 0.00
~ 6.10 6.10 53900. 1.237 0.637 0.00
6.20 6.20 54783. 1.258 0.659 0.00
6.30 6.30 55667. 1.278 0.681 0.00
6.40 6.40 56550. 1.298 0.702 0.00
E 6.50 6.50 57434. 1.319 0.722 0.00
~
6.60 6.60 58318. 1.339 0.741 0.00
6.70 6.70 59201. 1.359 0.760 0.00
6.80 6.80 60085. 1. 37 9 0.778 0.00
6.90 6.90 60968. 1. 400 0.796 0.00
7.00 7.00 61852. 1. 420 0.814 0.00
Hyd Inflow Outflow Peak Storage
Target Calc Stage Elev (Cu-Ft) (Ac-Ft)
1 1.27 0.24 0.37 5.22 5.22 46150. 1. 059
2 0.64 * .. * .. ** .. 0.16 4.85 4.85 42832. 0.983
3 0.77 * .... * ...... 0.14 4.28 4.28 37849. 0.869
4 0.66 * .... ** .... 0.14 4.35 4.35 38428. 0.882
5 0.69 .. ** .. *** 0.10 3.52 3.52 31085. 0.714
6 0.55 ...... * ...... 0.04 2.87 2.87 25331. 0.582
7 0.41 **** .. ** 0.04 3.00 3.00 26497. 0.608
8 0.62 ** .. **** 0.04 2.17 2.17 19203. 0.441
----------------------------------
Route Time Series through Facility
Inflow Time Series File:cvs3-dev.tsf
Outflow Time Series File:rdout
Inflow/Outflow Analysis
Peak Inflow Discharge: 1.28 CFS at 6:00 on Jan 9 in
Peak Outflow Discharge: 0.368 CFS at 11 :00 on Jan 9 in
Peak Reservoir Stage: 5.22 Ft
Peak Reservoir Elev: 5.22 Ft
Peak Reservoir Storage: 46150. Cu-Ft
1.059 Ac-Ft
Flow Duration from Time Series File:rdout.tsf
Cutoff Count Frequency CDF Exceedence _Probability
CFS % % %
0.002 27354 44.609 44.609 55.391 0.554E+00
0.007 5769 9.408 54.017 45.983 0.460E+00
0.011 5784 9.432 63.449 36.551 0.366E+00
0.016 5924 9.661 73.110 26.890 0.269E+00
0.021 4980 8.121 81. 231 18.769 0.188E+00
0.025 3920 6.393 87.624 12.376 0.124E+00
0.030 2846 4.641 92.265 7.735 0.773E-01
0.034 1593 2.598 94.863 5.137 0.514E-01
0.039 1595 2.601 97.464 2.536 0.254E-01
0.043 1193 1. 946 99.410 0.590 0.590E-02
0.048 37 0.060 99.470 0.530 0.530E-02
0.052 16 0.026 99.496 0.504 0.504E-02
0.057 11 0.018 99.514 0.486 0.486E-02
0.062 13 0.021 99.535 0.465 0.465E-02
0.066 9 0.015 99.550 0.450 0.450E-02
0.071 7 0.011 99.561 0.439 0.439E-02
0.075 29 0.047 99.609 0.391 0.391E-02
0.080 22 0.036 99. 644 0.356 0.356E-02
0.084 21 0.034 99.679 0.321 0.321E-02
0.089 30 0.049 99.728 0.272 0.272E-02
Year 8
Year 8
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0.026 99.754 0.246 0.246E-02
0.039 99.793 0.207 0.207E-02
0.021 99.814 0.186 0.186E-02
0.010 99.824 0.176 0.176E-02
0.016 99.840 0.160 0.160E-02
0.020 99.860 0.140 0.140E-02
0.018 99.878 0.122 0.122E-02
0.016 99.894 0.106 0.106E-02
0.013 99.907 0.093 0.930E-03
0.018 99.925 0.075 0.750E-03
0.031 99.956 0.044 0.440E-03
0.015 99.971 0.029 0.294E-03
0.005 99.976 0.024 0.245E-03
0.007 99.982 0.018 0.179E-03
0.005 99.987 0.013 0.130E-03
0.010 99.997 0.003 0.326E-04
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5.3.2 DlITENTlON TANKS
5.3.2 DETENTION TANKS
Dele1ltion tanks are underground storage facilities typically constructed with large diameter corrugated
metal pipe. Standard detention tank details are shown in Figure 5.3.2.A (p. 5-33) and Figure 5.l.2.B (p. 5-
34). Control structure details are shown in Section 5.3.4 begimring on page 5-38.
5.3.2.1 DESIGN CRITERIA
General
I. Tanks shall be designed as flow-through systems with Mauboles in liDe (see Figure 5.3.2.A, p. 5-33)
to promote sediment removal and facilitate maintenance.
Tho.eption: Tanks may be designed as back-np systems if preceded by water quality facilities since
little sediment sbould reacb the inlet/control structnre and low head losses can be expected because of
the proximity of the inlet/control structure to the tank.
2. The detention tank bottom shall be located 0.5 feet below the inlet and outlet to provide dead storage
for sediment.
3. The minimnm pipe diameter allowed for a detention tank is 36 inches.
4. Tanks larger than 36 inches may be cOlUlCCted to each adjoining structure with a short section (2-foot
IIllIXimum length) of 36-inch minimum dismeter pipe.
5. Outflow controlstrw:tores shall be as detailed in Section 5.3.4 (p. 5-38). Note: Control and access
manholes sluzll have additional ladder rungs 10 allow ready access to all tank access pipes wilen the
careh basin S1II1Ip isji/led willi waler (see Figure 5.3.4.A, pion view. p. 5-39).
Materials
Pipe material, joints, and protective treatment for tanks shsll be in accordance with Sections 7.04 and 9.05
of the WSDOTIAPWA. Standard Specification as modified by the King County Road Standards and
AASHrO designations. Such materials include the following:
• Lined corrugated polyethylene pipe (LCPE)
• Aluminized Type 2 corrugated steel pipe and pipe arch (meets AASHTO designations M274 and
M36)
• Conugated or spiral ri~ aluminum pipe and pipe arch
• Reinforced concrete pipe
• Narrow concrete vaults (see Section 5.3.3, p. 5-35).
• Corrugated steel pipe and pipe arcb, A1l1minjud or Galvanized" with treatments 1 through 6
• Spiral rib steel pipe, AJ1!1ninized or Galvanized with treatments I through 6
• Structural plate pipe and pipe arcb, AJnminiud or Galvanized with treatments 1 through 6
Structural Stability
Tanks shall meet structural requirements for overburden support and traffic loading ifappropriate. H-20
live loads must be accommodated for tanks lying lDlder parlcing areas and access roads. The King County
Roads Standards may have different live load rcquiremen1s for structnreslocated under roadways. Metal
a Galvanized merats leach tine Into the envlr'onment, especially In standing water situations.. High zinc concentrations,
sometimes In the range that can be toxic to aquatic life, have been ObseNed in the region. Therefore. use of galvanized
materials shouk!' be avoided. Where other rnelals. such as aluminum or stainless steel, or plastics are aveilable, they shall be
used. 111I1ese materials are not Ivallable, asph.~ "",,18<1 galvlnized ma1Brials may 1I10n be usec!.
2009 Suri"a<c Water Desian MBDuaI 11912009
5-31
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SECITON 53 DETENTION FACILITIES
tank end plates must be designed for structural stability at maximum hydrostatic loading conditions. Flat [.
end plates genetally require thicker gage material than the pipe and/or require reinforoing nbs.
TIIllks shall be placed on stable, well consolidated native material with a suitable bedding. BacldiIl shall [
be placed and compacted in accordance with the pipe specifications in Chapter 4. Tanks made ofLCPE
require inspection fur deformation prior to installation as well as continuous inspection of backfilling to
one foot above the top of the tank. Tanks sball not be allowed in fill slopes, unless analyzed in •
gcoteclmical report for stability and constructability. [
Buoyancy
In moderately pervious soils where seasonal groundwater may induce flotation, buoyancy tendencies must
be balanced either by ballasting with backfi1l or concrete backfi1l, providing concrete anehors, increasing
the total weight, or providing subsurfa<:e drains to permanently lower the groundwater table. Calculations
must be submitted that demonsllate stability.
Access Requirements
1. The maximum depth from finished grade to tank invert shall be 20 feet.
2. Access opeDiDgs shal1 be positioned a maximum of 50 feet from any location within the tank.
3. All tank access openings shall have round, solid locking lids with ',,_inch diameter Allen head cap
screws (secKCRSDrawing No. 7-022 and 7-023).
4. TIrirty-six-inehmiaimwn diameter CMP riser-type manholes (Figure 5.3.2.B, p. 5-34) of the same
gage as the tank material may be used for access along the length of the tank and at the upstream
terminus of the tank if a backup system. The top slab is separated (I-inch minimum gap) from the top
of the riser to allow for deflections from vehicle loadings without damaging the riser tank.
S. All tank access openings must be readily accessible by maintenance vehicles.
Access Roads
Access roads are required to all detention tank control structures and risers. The access roads shall be
designed and constructed as specified for detention ponds in Section 5.3.1 (p. 5-20).
Right-of-Way
Detention tanks to be maintained by King County but not located in King County right-of-way shall be in
a tract dedicated to King County. /uJy tract not abutting public right-of-way will requUe a IS-foot wide
extension of the tract to accommodate an access road to the facility.
Setbacks
Setbacks (easement/tract width) and building setback lines (BSBLs) fortanks ahaIl be the same as for
pipes (sec Section 4.1).
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5.3.2.2 METHODS OF ANALYSIS
1/912009
Detention Volume and Outflow
The volume and outflow design for detention tanks shal1 be in accordance with the performance
JeqUirmnents in Chapter 1 and the hydrologic analysis and design methods in Olapter 3. Res1rictor and
orifice design shall be according to Section 5.3.4 (p. 5-38).
2009 Suriioce w.tor Design MlIlua!
5-32
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5.3.2 DEfENTION TANKS
FIGURE 5ol.l.A TYPICAL DETENTION TANK
~ optional parallel tank
~ 1 -----~b/-(3'\
Inlet pipe
(beckup systems,
where aHowed)
A
l \......~ access risers I 36:".. )
I (max spacing shown below) i1 \'" .,~~ min. diameter m ~ _____________________ --1 r{ same a:nlel pipe
T J' t..EE:::{ o
control
structure
oontnol structure
(FROP-T shawn)
min, 54" dia.
Type 2 CB
see Section 5.3.4
NOTE:
All metal parts corrosion resistant
Steel parts galvanized and asphalt
coated (Treatment 1 or better)
access ri8Bm
5 .. Figure 5.32.8
PLAN VIEW
NTS
"Flow-through" system shown solid.
Designs for "flow backup' system and
parallel tanks shown dasheel
0.5' sediment storage
size as required
SECTIONA·A
NTS
"Row-through" system shown said.
5-33
Inlet pipe
\ (flow through)
"-type 2 CB required
for flow through
system only
2"' nin. diameter air vent
pipe welded to tank
(required ~ no access
riser on tank)
11912009
SECTION S.l DETENTION F ACILlTIBS
I FIGURE 5.3.2.B DETENTION TANK ACCESS DETAIL
standard type 2-60' diam.
119/2009
CB concrete top slab
36" CMP riser
standard locking
M.H. frame & cover see
KCRS dwg. no. 7-022
compacted pipe bedding
M.H. steps 12" O.C.
weld orOOI!
standard M.H. steps
NOTES:
PLAN
NTS
SECTION
NTS
frame locking lid
(marked "DRAIN")
mounted over 24" diam.
eccentric opening
maintain l' gap between
bottom of slab & top of
riser -provide pliable
gasket to exclude dirt
riser, 36" diam. min.,
same material & gage as
tank welded or fused to tank
...... dleleinllcln tank
1. Use adjusting blocks as required to bring frame to guide.
2. All materials to be aluminum or galvanized and asphalt coated (Treament 1 or better~
3. Must be located for access by maintenance vehides.
4. May substitute WSDOT special Type IV manhole (RCP only).
2009 Surfilco W_ Design Mlllual
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1lE UNDERSIGNED HEREBY N'PROVEI THE "nACHED III PAGES
INClUDING 11-1! FOllOWING:
• VOLUME. 48,957 CF
• MAINLINE PIPE GAUGE -14
• WALL TYPE. SOUD
• DIAMETER-72"
• FINISH. AL T2
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CVS PHARMACY N<A RETAIL PHARMACY -RENTON
RENTON.WA
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If ·~ AOCEI8 CAITINOlO IE
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,.-r--I -of J _____ L _____ ,.'-__ _ I .•• • ..... ~ ___ • ..". ... --:-~ t I -. ~ : 9' _
............... ".ft,.",, __
IILM RIDM 1fARlNQ0N
IIIIEIII TO 1Ef'MMDED BY
""'""""'"
1U-----·a.JIIISSIi
1-___ • I.
SEcnONVlEW
~
U ~.
.. _-
SAIl {n'P ... PLAI:DJ.
REINFORCING TABLE
IIICMPI
RISOR A II. REIfFORCING
... •• ... •• t2"DCEW .... •• t:rOCEW
". ..... ". ... t:roa;w
4'.rx .. · ... e.1Z'otEW ... •• •• •• ta-caw ... _.1I1"OCEW ... ..... ... •• 1a"OCEW
6'.rxr.r _.ro::aw ... .r ... •• roa;w r .. ..r~
-iIIIISUNEIl SOL IIEMlNrl CAPM:ITY
•
~ ! ""! I 0. ... -'~ II ! "" I ~I 'y.1---li J = '\ r~ S 'V.J--lh.-...
........ .......
-, .....
-" -W" ". " -----/·11 I ~ I .. k ;] ,; <;;;: """""
""'" 'TtIB.-a:FlC#I11OMCO\IEJISlHeMNfUMCTURIIKJINITM1A~OI"
1lE c:aRRUIIMTm sraa. Pl'ECCS"I DETAllBI II 1M! PfIOJI!CT PLNI8,
IIoW.LIE II' NQE'MlH RECIlFaEDlliT10NI OF ROUND OPTION PlAN VIEW SQUARE OPTION PLAN VIEW
!!!111!!!1.
nllEAI.lIIDRED1'I'I'I! 21T'1!1!L COILIIItW.1. CCttIQlM TD11f! AI'ft.ICMLE
RlCMREMEJrfTa OF M8HJa MI7 .. OR Alln.tMII.
""
1tE NAlIONIIL CORRUCMTED lITES. ,"-AUOeIAl1DN -"""""""
......
t. DBIGN II ·CCOAIMNCEWITH AAIIHrn. 11'1aoEDmON. 1. TRlMOPeOG'MT1ID~.1WtI.1IInDiD
UIaI"....aM OF tr E'¥'DND 0PENN8, IIEMI
2. OOIGM lQIIQHIa BAM MII£QUiRED TO tMaffMt BAR COVER.
:I. INrJM CCIIIER .. "II.\L .. IIROTEIIOM ILAII IINDAU.MA1ERiM.B TO lIE
PMMDED NCD NTAU.ED Sf CCIHl'MCOfOI(.
.. ~ UIIIEMG1H"3,IOOPill
"BEARING
PRESSURE
(PSFJ
2..'0 '.'" .. ..
'-'" ,-' .... ,.",
1,110
,.'" 1,1011
J •
'"""""""" ... -. .........
'TM: 0. 8tWJ. n 1lWU'AC:1\.MD It ACCIIJfIIWCI!;'Mnt TM!APPUC#IILE
RaIl ISdLdiaCFM8HJaAallORAlln.tAJa TtE,,"aaa.MGa
NIl COARUCMTa.1tW.L a&", IHOWN ON THE I'IIWECrPUNL
1tWJ.1E1I""""""M"'FwrTM~"'ANDMII
Ill'Ell:lFlCATlCIHII'QIIIi I«JIoMrAY ....... 8ECT1ON ..
DMBiON lOItAnMAJllNII .. ca'alU • ... a
WlTHlMI NDJiiCT'1VHI AND :nata
II'THEiFIiIiI#lll. »ItWCClNll81BK:El DfI CCIHF'LI:h
1M( CCIlrmW:'rattHOUUJ PIKUa AND 1Ii&SOL\I'E
WITH 1HE 1flEDaitHR. t. DETAIlDhlGHtyDEl.TAEMJI~BiNOHiWRlN.N'I'.
Ml. FMRICA'I1ONOf 'nil: I'fIODUCT ..... OCCUR WJT1'INTHI! INI., ..........
rJ E'3 ~ ~ ~
rrlSlIIL ... .,.1HE~OI"ntECOHTMCTOR
TO FOi.UMI OSHA 0I.IIDEI.JNeS rtlill we.1'MCIiCU.
___ -......:am __ "'1I'1~
CONiECH'
CMP DEmITIIIN MIEMS
I. ~S1EEL.ABnI ... tS.aRADElO.
I. ~MXIfJIOfW..~ARtUIID
CIPEJMGI; KAUIL TO TME aMS~
..... &AQf alOE. illlDlJfT1DJW. UIRII TO IE ..
IIE_I'WE.
® MANHOLE CAP DETAIL
P3 SCALE: N.T.s,
072' UNDERGROUND DETENTION SYSTEM -480574-020
CVS PHARMACY AKA RETAIL PHARMACY -RENTON
RENTON.WA
SITE DESIGNATION: --
~ f"""'l ~ ["""'I ~ ~ ~ ~ .-.., T'"1 ..---, r----'I rn r----";i
r
L
[
r
o
••
[I -,
"'~I~u ... r,..u ~~I" i ;;.vn
STORMWAlER "
--~UTIONSINC.
CONTECH Stonnwater Solutions Inc. Engineer:
Date
Site Infonnatlon
Project Name
Project State
Project Location
Enter Pipe I.D'-~_-,:7;:-2 --II!n.
Enter Desired Increment - 2 In.
Total VolumelLF
28.27
IneNum
WeIer
Level
(In.!
Inc Area Hyd Red Top Wldlh
(sq. ft.) (ft.) (ft.)
2 0.11 I.J7
4 0.22 2.r5
6 0.32 3.12
4 12 3.77
Round Pipe Stage
Storage Table
CRt-'
6121/2013
CVS Pharmacy
WA
Renton
Total CMP Length= 1702 ft.
System Invert-369.62 ft.
Volume
(ef)
37f
105
1915
2923
WS
EleveUon
2
rO.2
r-~ __ r-~18 __ +-~~~~I.M~+-_~5; .. ~20-4~~~08~~Y~I.~t
10 20 6.41 5.37 10908 371 ,
12455 71.4
14042
15662
o. 17310
30 5 18979
12.14 i.96 372.2
13.14
29144
44 18.10 1 5.65 30813 3732
19.07 246' 1.4
1.0
27 54 22.75 !O 38715 374.12
28 ;6 23.60 (,99 60 374.29
-4--~~-r~~~~~~ ~ ~~~~~~~~~~~~~~~~~51~~ ~
15200 :---16 46206
68 .71 '1
5 70 28.05 1.97 375.4
6 72 J8.27 0.00 ·8 !3 375.6
These results are submitted to you as a guideline only, without liability on the part of CONTECH Construction Products
Inc. for accuracy or suitability to any particular application. and are subject to your verification.
Corrugated
Metal Pipe
Design Guide
Backfill
L
~~I~IU .. r~U· [
"'~"I" i; V!! " I DRAINAGE SOLUTIONS I
., Bedding ~
[
[
("
S"a ' .... 3"a' .. H.I.hNf.Cov •• LI ...... f •• C
C .......... lteal Pip. ,
I
H 20 and H 25 Live Laad.
MGJldrnum Covet, ,_tl:II
Diameter Mlnlmum Sp.~d 1hlclm~ ... Inche.
erSpan, Cove,
Inthell Inchru 0.064 0.079 0.109 0.138 0.168
54 12 56 70 98 126 155
[ 60 50 63 88 II. 139
66 46 57 80 103 126
n 42 52 73 95 116
78 39 48 68 87 107
84 36 45 63 81 99
90 33 42 59 76 93
96 12 31 39 55 71 87
102 18 29 37 52 67 82
108 35 49 63 77 r 1i4 32 45 58 71
120 30 41 54 66
126 39 50 62
132 36 47 57
138 33 43 53
144 18 39 49
MOJliimum cover heighb snown 0", for 5~ x l~.
To obtain maximum cover for 3-x 1·. Increase .nnll valulI' by 1 3'%
E 80 Uva Laads
Maximum C-, feetC1I
Dlamet.r Minimum 5p~d lhidm .... Inches orSpCln. C ... ,
Inch •• Ind.1 0.064 0.079 0.109 0.138 0.168
54 18 56 70 98 126 155
60 50 63 88 114 139
[ M I 46 57 80 103 126
72 18 42 52 73 95 116
78 24 39 48 68 87 107
SA 36 45 63 81 99
90 33111 42 59 76 93
96 24 31 111 39 55 71 87
102 30 2911 1 37 52 67 82
108 35 49 63 77
114 32 m 45 58 71
120 30 301 11 41 54 66
126 36 39 50 62
132 I 36 47 57
138 I 33{1] 43 53
144 36 I 39 49 ,
Maximum~ighb shown are for S" II: 1 ".
To obtain mgxjmum cover Jor 3-.'II 1", increaM! these vokles by 13%..
III These diamellln in these gaUges require additional minimum CCIIer.
5" x , .. Plpe-ANh Hal.hHof Cove. Limits f ••
Corn.a .. d 1 ... 1 Plpa 0 H 20 and H 25 Live Loads
s ... Minimum Mmmuml71
Elluiwr1ent Spedfied MinImum Cover, Fe.t
Pipe Span.RiM Thlckn .... C ... , 210n./ft.'1. COWIr
Diameter Inchea Inch •• • Inch •• Bearing Preuure
72 81 x 59 0.109 18 21
78 87.63 0.109 18 20
84 9S x67 0.109 18 20
90 103.71 0.109 18 20
96 112 .. 75 0.109 21 20
102 117 Jt 79 0.109 21 19
108 128x 83 0.109 24 19
114 137.87 1 0.109 24 19
120 142:11; 91 0.138 24 19
E 80 Uv. Loads .... MInimum Ma.tmum!11
IlIuiYalent Specffied Minimum Cewer, ... t
Pip. SpanxlU .. Th/dr.n •• ., ...., 2 Ton./Ft.'" CoYer
DlCIIIMI'.r Inche. Inch-.· IncMs ..... "" Preuure
72 81 x59 0.109 30 21
78 87:1163 0.109 30 18
84 95 x 67 0.109 30 18
90 103.71 0.109 36 18
96 112 x 75 0.109 36 18
102 117)1 79 0.109 36 17
108 128.83 0.109 42 17
114 137 x 87 0.109 42 17
120 142 x 91 0.138 42 17
... Some 3" x I" and 5" x 1 ~ minimum gauges snown for pipe-arch are dUI!I to
monufadurlng lirnikltions.
.... 'aht..af.cOWl' not ..
1. Th.", tables are for Iadc-seam or welded-wam conltruction. They are not
for riveted construction. Consult your CONTECH Sales Repre5enlative for
height-of...cover tables on riveted pipe.
2. These vollIeS, where applicable, were cokulaied using K-O.86 0$
adopted in the AISI Handbook. Fifth Edition, 199 ....
3. ne span and rise shawn in these tablel ore nominal. Typicaly the actual
rise that form! is greeter than ihe spedliDd nominal. nis oduol rise is
within .nit toterances os alowed by the MSHTO & ASTM specifications.
Thlt minimum covers shown above toke in to consideration IIlls plus
tolerance on ri108.
4. The hound! areas of 0 pipNrch are the moll critical zone for baekfilling.
Extra core should be token 10 provide good material and compaction 10 Q
point above the spring line.
S. E 80 minimum cOVltr II meosurad from top of pipe 10 bottom of tie.
6. H 20 Qod H 2S minimum cover Is rneosureci from top of pipe to bottom of
flexible pavement or top of rigid pavement.
7. The H 20 and H 2S piplt-Orch tables are based 0f1 2 Ion5 per square loot
corner bearing preuures.
S. The E 80 pipe-arch k1b1es minimum and mQJlimum covers are based
on the comer bearing pressu""s shown. Theile values may Increase or
decrease with chcJnges in onowoble comer bearing pressures.
9. 0.OS2-II 18 gouge.
0.064-1,16 gauge.
0.079" Is 14 gauge.
0.109" is 12 gauge.
0.13S" ill0 gauge.
0.168-is 8 gouge.
10. For canslrudion loads. see Page 12.
11. SmoothCar and HEl-COR Concntle Uned hove .ome height-okover
properties os cort\lgoted steel pipe. The elderlor shell of SmoothCor is
manuJoctured In either 2.J/1-x liz-or 3 x 1 corrugotions; maximum
exterior shell gauge is 12.
9
SECTION A-4: CONVEYANCE CALCULATIONS Rational Method· Conveyance c.akuladons
Unll'nk Nann.IF! .....
lebl !
.. -...... ' "AzJ"'" "!!,sofa, _of ....... SUlt-batn ZSO Tot" zs..,.. DIIpth In ,Ipo: o.,,",,of
~ """" .. -.. ... ~ ' ..... ,...." '-'-'~ Inll!nllt¥fKhlr I'M.""""" ... , ..... Pelt FIIIw to !FbIAI"_, F ... baardl" "'"-'-'
511b-1asin Ib AID ",,_I I..Inclcav.r 'c"' "p .. o ' .-' .-' "T~' .... lnt.n11ty"1s .. Flo'It'Qn' _ma "po PIpeD'-bIr 1'I ... 51Dpe ~ ... .,...., "po -' ... Freebaltd
CA<l lin' '''''''I ,-''''I ,dol '"I ... Iftjftl 'It] Iftl .. .. -... m ... .. .H ... ... , ... '.n • n "" ." 0 , ... .." "'. . ... . ... B •
<lIS , ... .m .. , .. , .. .os ., .OO .." .n .... . ... • .... o.ln .... .... U3 .., .... " 11.3' .... .. .. .... , ... ., • oo '.n .It "" 0.91 , .SO ..... .... .n u 2>. .... ~ ,.., •• .. ,. .H , ... ., .... '.73 ." .... ." • ." .m ... IU. '.00 4.]5
"'" , ... .. .. , .• . .. . .. ... ... '.n ." CO" ... • ." .on .. ." '-', U,
17 0.2" ••• .. "'6 ... .. , ... '.n ." "" ... • .n .'" lUI ... U3 u,
"" , ... ... .. U .... , ... '.1 , ... ." .. , cm .." .. U. . .. . .. "" .... 'IS
CO ... 0.07 .. .. .. . ... , ... ., ... '.n ,17 ClIO .. , • ." ..... . .. . .. , .. m .. " ,m ...-.. .. .. 2.16 , ... ... . .. '.n "" "" ..., .. '00 .-, ... .., .... 3.0
'"" ... " .. .. . ... . .. .. ... '.n ... UG IMt. 5¥S-.... IS L15 .... <U2 "" ..,. ....
C_ ,." "-, ... .. ... , ... .. ... W '.0 '"" •. " .. LOO .... . .. .... LS' ,"
CU7 ... ,-m .. .. , .. , .. . .. ... ... m ... OUIlat!ilr. . .. • •. " . ., ... 0.4' ,.U .n , .... . .. " ., .. , .. . .. U . .. Ln ." cut< 0,07 • ." .on ,.~ ... I." W
"'" ,.11 ., .. 14 ... . .. ... . .. ,n 02' COl" .... • ." , ... .... 0.5Z 2.43 LOS , ... •• U . .. . .. .. . .. W '.IS a", ... • ." ... ... D.4l "3 " ..
"'" 0.01 "' .. u . ... ... ., ... •. n om '" """ .. , • ." ." ,,. 0.41 ,n .14
D1IdI ... • '"~ • '"~ ". • ". ". '"~ • '"~ '"~ ..... • .. , .... , ... ... '.00 1.43 ". ". "" "" '"~ '"~ ". '"~ "" "" "" ... .. 100 .... , .• . .. '00 '10 -1 Mf ... "'Shnt0-1fvrAfu
11llI'wtaSMebD.l."'a.I Parsla,.
1 "',. ... ZCIOI5WDM ~IIAIMdIllull ~
.. IIIscNrp pipe fnNn DllbllIIkMI/WCl trnIInIm fKIIItIH h_ i IIIiIII:tnIum slape oJ g,5'IIj I11III100''''101' IIDw lit g J cts
~ ~ ~ ~ ~ ~ r"IJ ~ r-j F'""'1 ~ r"! ~ ~ ",.,..." ~ r""'"1 ",.., r-' --,
"
,
!
r ~
";N' ~ I ~~
c:i~ ct:, i ~ • g§:G
<t:
'-' •
. .. -.'
; . . '
I ' ; , . i
->
Wi-••
J"jUIA ' i
--
·l~ -$-. != <-[-----.. "
i
<
/
~~
~l! • ~
i ,
, I' I
I
i
, .
• !
!
• s
[
[
[
[
~
[
[
u
u
u
-~
= ~ ~ ~ ~ ~ ~ I""I!""l ~ r-1 r, .,} ~ ~ ~ !:J ~~ J .--, f""l7j r::-)
Siotion
I
I
-. Sto1ion ,7' ---0+.00 l+,utI1V'J _~ S1ol,on D-+oOQ 1+-1+ ~.' ...... , .. --~"!l;~ __ •• JJQII "',uu lr'll·m~ .:~ \' -= 1 I ..... l_, lru_DW 0+00 1+00 2+00 2+]6 __ / ,J'[I_lJ!.5.0
II" ~~:-.': •• \ V 1_.5 tr .1-"'.11 r ~I: ~~: -::. _ <la..::.:".'1:'
It'.::.;. =: __ ~, ./ ~ .... JII.ZI ~ ...La.AJIl. 1m ~ l!'D-11',:: ~ w,.:. [1ft J!!IO
_..,IIIUI ....: I ./ -'-~TU ~::=: 3!H]or-:--ll:::::':':: ,.':".::.-: 390 "_I"" IIII1,Ml. ,L ~ n,
-
r
. )1 -'.-. or •• ·_. ..~~ 1(;--....... ,......,..,.. ... ·m" ),1 -.,~ I'~ 111 __ .... _..... _l1li !lisa.... f::7 -',!"':. 1Illll-1U1f11 ~ ... "D
37 JI~ ,F:O ....... ~II,W<. r=-MOUUIJ ~: ~~1i ~·"':lo-l~l"j----r j \=L;;-:~:::: I
FlU rL ~ u "§t::..-' -1t"" "t> ~.;-,.. .... ,,,a f U, L.-~_ 11"1 •• " ~ fn'~ 1-0
I[oJIUI "V I MIT..-"_ r-'"
MUg'r...... w.s. ::~t:::! '1 fm--.... ;:::."::. ,lWt __ "".0011 _
36 00< 360 ~I I lJU J 360
O-fOO ,,1"111'11".... 1+ __ 13 37 I J70 0+00 .""If·~J 1+00 t+J7 • 1CIP't_""'.... ...._-.. ., ... .,.""
MHffl-DETSYSPROF1LE L:..".:c .. ..:. l''' .... ~.J 7.5 ..r • ..,. :::".~-
"'" PC -::N~:II&II C~IIIO-DHSYS!ROFILE
~.
36 60
0 ... 00 1+'00 2+00 2+)6
eBlt! -C81112 PROFILE
Sh,iion
0+00 '+po 2+00 )+00 "+00 H2O SlotlDn
'"<12.1 O~OO '-1-00 1-+-:;4 StatlDn :--
-"'j--------i--------t.;;;tii="-----i---------f-----~OO 0+00 0+ Z~'i --r~C:=-n Ir~-Itn.... ~. r= ..... ~'.':'m.J' ::--.W'"I--~~~~~ =-_:wO .,·nUII '-1U~
1'(I.JJl.II _.a. ~, ,~~ ... (_~ ', .... oa 1I""11_Jll.1I '\. ... J1UiI
......... 11 r:='-~::..::: 1:, __ 111. ":.:-.::: I Pot .:::::.! / J '~_~D
.. m ~~ :iE Ir--::= I~L ~~.;.~. -tlU i.~:a~': ../..A:, ~rH "''''''''' •. -'' ""r/i.-·r:::c.. -.J-.... ~. _fa: -.... ~ J . J ~.' ow 1I" .... mJII ' "1 .. n,.<1 \ :lID .... "., ~.
II"I .. JPI.M ~s,:::::: _ ~n HU
:.:'".= 81....... -~ -~ 18 -I.r -.J =~ .no·=1 J7(l
/ /'":] liltS \.r".w.Il I ....... J>n .,' .. n
38 L -~¥"-U JI!O ..... ""'., 1111.1"" . L l_o ~. I v" c_"" N IIUI__ lU 1----
H"--,.......' .1'L no "0--'.-=: --~.--"0 .n
\., "1::'1: 1!o.ll ':'II~-;": L. .. & J J60
tr 12111."''' Oil."" I"n ""'f". r-'O 0+00 0+46 =.~-::'II~-i" f-II ~:.rs:.. 37 . :370 ..... _ ....
~• L~l.5 : __ .S OUTlET STRUCT -CBH7 PROFILE
,2'" ,.,,,.... r-' l 360
~:{,:. ::~..... full 0+00 1+00 1-*5"
'"'lll'. pta STl!!-_B,~DGPROFIL£ rl-·==;-' --'1
0+00 1+00 2+00 3+00 4+004+io
60
-.• ~:
~-CIW6PROF!~~ I ""',:!!IIOJ-Il[ I-~ -IIF~'£:~lARH)=l _ r.. ____ (ClVlJ -,-.(" ... .--....
--m. __ -_ ..,..~ ~
--a ' -lQ ~ VElMEIR RETAIL PHARMACV =-
n STORM PROfiLES SITE =;.;-
CJI'I"IS .",. W/IIJ'JCIUI lUll tl".'l. '" /!ii' .. I ~:.!!.. I _'"'lUI L I 8
... __ .. CIIoIt_ ~ :". ... -~
I I I I I I I
• 3.2.1 RATIONAL METHOD l
3.2.1 RATIONAL METHOD
The Rational Method is a simple, conservative method for analyzing and sizing conveyance elements
serving small drainage subbasins, subject to the following specific limitations:
• Only for USe in predicting peak flow mles for sizing conveyance elements
• Drainage subbasin area A cannOI exceed 10 acres for a single peak flow calculation
• Tbe lime of concentration To must be computed using the method described below and cannot exceed
100 minutes. It is also set equal to 6.3 minutes wben computed to be less than 6.3 minutes.
Note: Unlike other methods of computing times of concentmtion, tbe 6.3 minutes is not an initial
collection time to be added to the total computed time of concentmtion.
[J RATIONAL METHOD EQUATION
The following is the tmditional Rational Method equation:
where Q.~
c
f.
A
"C" Values
peak flow (cfs) fora storm ofretum frequency R
estimated runoff coefficient (mtio of minfall that becomes runoff)
peak rainfall intensity (incheslhour) for a storm of return frequency R
drainage subbasin area (acres)
(3-1 )
The allowable runoff coefficients to be used in this method are shown in Table 3.2.I.A (p. 3-13) by type
ofland cover. These values were selected following a review oftbe values previously accepted by King
County for use in the Rational Method and as described in several engineering handbooks. The values for
single family residential areas were computed as composite values (as illustmted in the following
equation) based on the estimated percentage of coverage by roads, roofs, yards, and unimproved areas for
each density. For drainage basins containing several land cover types, the following formula may be used
to compute a composite runoff coefficient, Co:
wbere At
A ,.L .. n =
C/,], ... n =
total area (acres)
areas ofland cover types (acres)
runoff coefficients for eacb area land cover type
"'." Peak Rainfall Intensity
(3-2)
The peak rainfall intensity f. for the specified design storm of return frequency R is determined using a
unit peak rainfall intensity factor i. in the following equation:
where
(3-3)
p. = the total precipitation at the project site for the 24-bour dumtion storm event for tbe
given return frequency. Total precipitation is found on the Isopluvial Maps in
Figure 3.2.I.A through Figure 3.2.I.D beginning on page 3-14.
i. the unit peak rainfall intensity factor
Tbe unit peak rainfall intensity factor i. is determined by the following equation:
2009 Surface Water Design Manual 1/912009
3-11
.. -\
[
[
[
[
['
rl.·, lj
[
[
[
SECTION 3.2 RUNOFF COMPUTATION AND ANALYSIS METHODS
11912009
where T = ,
(3-4)
time of concentration (minutes), calculated using the method described below and
subject to equation limitations (6.3 S T, S 100)
coefficients from Table 3.2.1.B (p. 3-13) used to adjust the equation for the design storm
return frequency R
This" iR" equation was developed by DNRP from equations originally created by Ron Mayo, P.E. It is
based on the original Renton/Seattle Intensity/Duration/Frequency (tD.F.) curves. Rather than
requiring a family of curves for various locations in King County, this equation adjusts proportionally the
Renton/Seattle I.D.F. curve data by using the 24-hour duration total precipitation isopluvial maps. This
adjustment is based on the assumption tbat the localized geo-climatic conditions that control the total
volume of precipitation at a specific location also control the peak intensities proportionally.
Note: Due to the mathematical limits of the equation coeffiCients, values ofT, less than 6.3 minutes 01'
greater than 100 minutes cannot be used. Therefore, real values ofT, less than 6.3 minutes must be
assumed to be equal to 6.3 minutes, and values greater than 100 minutes must be assumed to be equal to
100 minl/tes .
.. T," Time of Concentration
The time of concentration is defined as the time it takes runoff to travel overland (from the onset of
precipitation) from the most hydraulically distant location in the drainage basin to the point of
discharge. Note: When C, (see Equation 3-2) of a drainage basin exceeds 0.60. il may be important
to com pule T, and peak rate offlow from the impervious area separate{v. The computed peak rate of
flow for the impervious surface alone may exceed that for the entire drainage basin using the value at
T, for the total drainage basin. The bigher oftbe two peak flow rates shall then be used to size the
conveyance element.
T, Is computed by summation ofthe travel times T, of overland flow across separate Oowpath
segments defined by the six categories ofland cover listed in Table 3.2.I.C (p. 3-13), which were
derived from a chart published by the Soil Conservation Service in 1975. The equation for time of
concentration is:
T,=T,+T,+ ... +T. (3-5)
where T -I.l •.• .n -travel time for consecutive flowpath segments with different land cover
categories or flowpath slope
Travel time for each segment t is computed using the following equation:
T, L
60V
where T,
L
V
=
=
(3-6)
travel time (minutes) Note: T, through an open waleI' body (such as a pond) shall be
assumed to be zero with Ihis method
the distaoce of flow across a given segment (feet)
average velocity (fps) across the land cover = k. F.
where kR = time of concentration velocity factor; see Table 3.2.I.C
s. = slope offlowpath (feetlfeet)
3-12
2009 Surface Water Design Manual
.
r
3.2.1 RATIONAL METHOD t
TABLE 3.1.1.A RUNOFF COEFFICIENTS· "C" VALUES FOR THE RATIONAL METHOD
General Land Covers Single Family Residential Areas .
Land Cover C Land Cover Density C
Dense forest 0.10 0.20 DU/GA (1 unit per 5 ae.) 0.17
Light forest 0.15 0.40 DU/GA (1 unR per 2.5 ae.) 0.20
Pasture 0.20 0.80 DUiGA (1 unit per 1.25 ae.) 0.27
Lawns 0.25 1.00 DUiGA 0.30
Playgrounds 0.30 1.50 DU/GA 0.33
Gravel areas 0.80 2.00DUlGA 0.36
Pavement and roofs 0.90 2.50DUlGA 0.39
Open water (pond. lakes, 1.00 3.00DUlGA 0.42
weUands) 3.50 DU/GA 0.45
4.00 DU/GA 0.48
4.50DUlGA 0.51
5.00 DU/GA 0.54
5.50 DU/GA 0.57
6.00 DU/GA 0.60
Based on average 2.500 square feet per lot of impervious coverage.
For combinations of land covers listed above. an area,weighted 'C,:x A," sum should be computed based on the
equation C,: x A, = (C, x A,) + (C, x A,) + ... +(C,x A.), where A, = (A, + A, + ... +A,), the total drainage basin area.
TABLE 3.2.1.B COEFFICIENTS FOR THE RA TlONAL METHOD "I," EQUA TlON
Design Storm Return Frequency a, b.
2 years 1.58 0.58
5 years 2.33 0.63
10 years 2.44 0.64
25 years 2.66 0.65
50 years 2.75 0.65
100 years 2.61 0.63
TABLE 3.l.I.C II. VALUES FOR T, USING THE RATIONAL METHOD
Land Cover Category k.
Forest with heavy ground litter and meadow 2.5
Fallow or minimum tillage euHivation 4.7
Short grass pasture and lawns 7.0
Nearly bare ground 10.1
Grassed waterway 15.0
Paved area (sheet flow) and shallow gutter flow 20.0
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2009 Surface Water Design Manual 119/2009 c 3·13
[ SECTION 3.2 RUNOFF COMPUTATION AND ANALYSIS METHODS
FIGURE 3.2.I.C 25-YEAR 24-HOUR ISOPLUYIALS
!
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WESTERN
KING COUNTY
2S-Year 24-Hour
Precipitation
in Inches
1/9/2009
o 2 4 Mile!> 1 ,
3·16
I
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_ $.0
1. 4.5
'.. A~ l.r':'~~/
2009 Surface Water Design Manual
Typical FlowMaster Report
Conveyance Calculation for CB #6
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coeffldent 0.010
Channel Slope 0.02600 ftlft
Diameter 0.67 ft
Discharge 0.27 ft3/5
Results
Normal Depth 0.15 ft
Flow Area 0.06 ft'
Wened Perimeter 0.65 ft
Hydraulic Radius 0.09 ft
Top Width 0.55 ft
Critical Depth 0.24 ft
Percent Full 21.9 %
Critical Slope 0.00382 ftlft
Velocity 4.73 ftls
Velocity Head 0.35 ft
Specific Energy 0.49 ft
Fraude Number 2.59
Maximum Discharge 2.76 fllis
Discharye Full 2.57 ftl/s
Slope Full 0.00029 ftlft
Flow Type SuperCritical
GVF Input Data
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps a
GVF Output Data
Upstream Depth 0.00 ft
Profile Description
Proftle Headloss 0.00 ft
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 21.90 %
Downstream Veloctty Infinity ftls
Bentley Systems. Inc. H ... tld Methocb SoIlI6aa ...... M .. ter Val (SELECTMtI" 1) 108.11.01.03)
27 IlamoM Company Drive Sutte 200 W W.tertown, CT 06795 USA +1~03-755·1IS6 Pllge 1 of 2
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GVF output Data
Upstream Velocity
Nonnal Deplh
CriUcal Depth
Channel Slope
Critical Slope
6/18120132:35:40 PM
Conveyance Calculation for CB #6
Infinity IUs
0.15 ft
0.24 ft
0.02600 run
0.00382 run
eenUeySyHernll,lnc. Haested Method. SoJlliall~Ht.r VII (SELECr .. ri .. 1) (01.11.01.03]
27 Siemon. Company Drive Suite 20G W Watertown, CT 06795 USA +1-203·755-1&&& Page 2 of 2
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Table 4.2.1.Al -ALLOW ABLE PIPE MATERIALS AND MINIMUM COVER
AUowed
Minimum in Zone 1
Cover orlhe
Pipe Type (Il) Public Private APA E
Corrugated Steel Pipe 2.0 Yes Yes Yes
Spiral Rib Steel Pipe 2.0 Yes Yes Yes
Plain Concrete Pipe (PCP) 2.0 No Yes No
Reinforced Coocrete Pipe (RCP) 1.0 Yes Yes No
Corrugated or Spiral Rib Aluminum Pipe 2.0 Yes Yes No
Ductile Iron 1.0 Yes Yes Yes (
Line Corrugated Polyethylene Pipe (LCPE) 2.0 Yes Yes Yes
Corrugated Polyethylene Pipe (CPE) -Single Wall 2.0 Yes Yes Yes
Polyvinyl Chloride Pipe (PVC) 3.0 No Yes Yes
Solid Wan High Density Polyethylene Pipe (HOPE) 2.0 Yes Yes Yes [
For pipe specifications including acceptable pipe joints see RMC 4-3-050S.
Pipe Alignment
• Insert the following Table 4.2.I.A2 b~rore Table 4.2.1.A for allowable lengths between structures:
Table 4.l.1.A2 -PIPE SIZES AND LENGTHS BETWEEN STRUcrURES [
PIPE SIZES AND LENGTHS BETWEEN STRUCTURES
Upstream Structure Minimum Slope (%) and [
to Downstream Pipe min. Full Flow Velocity (fps) Maximum Length
StructuTe Diameter (In) at Design Flow (ft) Wbere Allowed
Inlet to CBIMH 12 0.5o/~ 3.0 fils 60 Public, See Note I
(;
Inlet to CBlMH 8 O.5o/~ 3.0 ljls 40 Private
CB toCB 8 0.5·/~ 3.0 (ps 100 Private
CBIMH to CBIMH 12 or greater 0.5%,3.0 ljls 300 Public
Note I. Minimwn pipe size shall be 12-inch diameter, 8-inch diameter may be pennitted on cross street laterals less than 66
feet to avoid utility conflicts or to meet shallow grade.
Note 2. Maximum spacing on surface drainage course between inlets and catch basins shan be 150 on grades less than 1 %
and 200 feet on grades from 1 % to 3%. Otherwise, maximum spacing shalt be 300 feet on grades over 3%, or as required
by grate flow capacities. Maximum CB to inlet spacing may need to be reduced depending on street width and inlet
capacity analysis in Section 4.2.1.2
Note 3. Minimum slope and full flow velocity is desirable unless it can·t be achieved due to outlet control, site topography,
burial depth or other situations or conditions.
2009 Surface Water Design Manual Amendment City of Renton
4-3
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S. PIPELINE MATERIAL:
1. PIPELINE MATERIAL REQUIREMENT
Pipe Diameter in Inches
Suggested Material Considerations (See
Pipe Material <4 4-8 10-12 14-20 24-30 36-54 Spec sUbsection S2)
Ductile Iron, Rubber
Gaskets
1.2 1.2 1,2 1.2 1.2 AWWAC151. C104 abcdnopr
Cement Mortar-Lined
1,2 1,2 1,2 1,2 1,2 AWWAC151 abcdnopr
Polyethylene-Lined
Ductile Iron, Nitrile Gaskets
1,2 1,2 1,2 1,2 1,2 AWWAC151, C104 bcdinopr
Cement Mortar-Lined
1,2,3 1,2,3 1,2,3 1,2,3 1,2,3 AWWAC151 bcdeinopr
Polyethylene-Lined
PVC, Rubber Gasket
Joints
1,2 1,2 1,2 AWWAC900 abjlnoprt
CL 150 or 200
1 1 ASTM D3034
SDR35
1,2,3 1,2,3 AWWAC900 bijlnoprt
PVC, Nitrile Gasket Joints
CL 150 or 200
2,3 1,2,3 1,2,3 hjklnoprt
-
r:"":'J ,.",.". t.:..:.~"_'
PVC, Solvent Welded
Joints
Sch 80
Welded Steel, Rubber
Gaskets
Cement Mortar-Lined
Dielectric-Lined
Welded Steel, Welded
Joints
Cement Mortar-Lined
Dielectric-Lined
High Density Polyethylene
Pipe
Corrugated High Density
Polyethylene Pipe -
Smooth Interior
Slip Form Liner
PIPELINE SERVICE
1. Storm Sewer
2. Sanitary Sewer and Side Sewer
3. Leachate Pipeline
4. Rehab Existing Storm Sewer
E'!J ~ F:£.] ~
1,2 1,2 1,2
1,2 1,2 1,2
1,2 1,2 1,2
1 1 1
4,5 4,5 4,5
~ !"""""I r'""'I
ASTM 01784,
01785
1,2 1,2 AWWA C200, C205 abfghnopr
1,2 1,2 AWWA C200, C210 abfghnopr
1,2 1,2 AWWA C200, C205 fghnopr
1,2,3 1,2,3 AWWA C200, C210 fghnopr
1,2 1 ASTM 01248 and hkpqu
03350
ASTM 01248 and
1 1 MSHTO kpqsu
4,5 4,5 ASTM 0638 mnopqr
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5. Rehab Existing Sanitary Sewer
2. CONSIDERATIONS ON SELECTION OF PIPE MATERIALS I
The Utility maintains a list of materials meeting perfonnance standards. Other materials meeting similar perfonnance
standards or developed as the result of new technology may be approved by the Utility.
I
a. Rubber gaskets may be severely damaged by petroleum products, particularly in prolonged exposures to concentrated I ,
flows containing little or no stonnwater or sanitary sewage. In cases where heavy concentrations of petroleum products may I
be experienced, nitrile (Nitrile-Butadiene; i.e., NBR) gaskets should be used.
b. Gasketed joints may not be leak-proof at zero or low pressures, if improperly installed.
c. Mechanical joints may be less likely to leak at low pressures than push-on jOints.
d. May need protective coatings and/or cathodic protection against external corrosion.
e. Considered most reliable gasket and lining material for ductile iron leachate pipeline.
f. Very difficult to repair linings on inside of joints In pipe smaller than 24-inch diameter.
g. Almost always needs protective coatings and cathodic protection against external corrosion.
h. Properly made joints are considered leak-proof.
i. Nitrile gaskets may require long delivery time.
j. Requires special attention to bedding and backfill depth to avoid structural failure of pipe.
-----
k. Large thermal expansion coefficient. May need to limit solvent welded jOints to 4-inch and smaller pipe. May require
careful evaluation of pipe installation temperature and temperature of piped liquids to ensure Joint integrity.
I. Pipe not available over 12-lnch diameter.
m. Slip form lining Is available in 6-lnch through SO-inch diameter for almost any pressure, If sufficient pipe cross-sectional
area is available.
n. Pressure grouts and gels are not acceptable for rehabilitation or patching of storm and sanitary sewers.
o. Suitability of pipe lining and gasket material to resist chemical attack by conveyed fluids must be determined for each
pipeline service considered.
p. All storm and sanitary sewer manholes, catch basins, and Inlets should be equipped with precast concrete bottom and
sidewalls with rubber gasketed joints between sections, water-tight epoxy grout or other approved pipe entrances through
walls, and approved waterproof coating of all interior floor and wall surfaces. Manholes, catch basins, and inlets should have
no leakage when hydrostatically tested at atmospheric pressure.
q. Has good resistance to a number of chemicals, petroleum products, and hydrogen sulfide corrosion.
r. "Zero leakage" test requirement may be Impossible to achieve under the best conditions for any pipe materials because
trapped air may distort test results, even in a drop-tight pipe. Pressure and leakage test requirements should consider
whether the pipe has steep slope or will stand full of liquid. Pipelines should be tested with the intent to prevent or minimize
leakage. Air testing should not be allowed; hydrostatic testing should be as stringent as any found in the industry.
Pipe materials, without regard for chemical attack, corrosion, or puncture, are generally ranked as follows, in decreasing
order of liquid-tight reliability:
" welded steel with welded joints
• PVC with solvent welded joints
• slip form liner I
c:::J E:'!'! ~ ~ ~ ~ ~ "....." ,..,-, r-1 ".. ~ .......... ~ ",.-" .,.,....., ,........, ,......, r-,
~~E::!!!~r:::::=I~~~~~~~f!'!I'I"!l~~""""""'r""'l""'"
• ductile iron with viton or rubber gaskets I
• welded steel with rubber gasketed joints
· PVC with viton or rubber gasketed Joints
s. Joints should consist of "heat-shrink" wrap. standard corrugated coupling. and full pipe band clamps.
t. The use of PVC may be restricted by other Utility policy in regards to depth of pipe cover.
u. HOPE may be adversely affected by solvents; Its use is not recommended where contact with solvents may occur.
COrd. 4851. 8-7-2000)
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SECTION A-5: WATER QUALITY
C~'~NTECH
ENGINEERED SOLUTIONS
CONTECH Stormwater Solutions Inc. Engineer.
Date
Site Information
Project Name
Project State
Project location
Total SHe Area, AI
Building Area, Ab
Drainage Area, Ad
Impervious Area, Ai (PGIS)
Pervious Area, Ap
% Impervious
Runoff Coefficien~ Rc
Upstream Detention System
Peak release rate from detention, 0.-. .... ,
Treatment release rate from detention, 0... ...... "
Detention pretreatment credit
(from removal efficiency cales)
Mass loading catculatlons
Mean Annual Rainfall, P
Agency required % removal
Percent Runoff Capture
Mean Annual Runoff, V,
Event Mean Concentration of Pollutant, EMC
Annual Mass Load, M... ..
Filter System
Filtration brand
Cartridge height
Specific Flow Rate
Number of cartridges· mass loading
Mass removed by pretreatment system, Mp"
Mass load to filters after pretreatment, Mp...,
Estimate the required fiHer efficiency, Eo .. ,
Mass to be captured by filters, Mo"or
Allowable Cartridge Flow rate, 0...
Mass load per cartridge, M... (Ibs)
Number of Cartridges required, Nma ..
Treatment Capacity
Determine Crttlcal Sizing Value
Number of Cartridges using 0.., ....... " N_
Method to Use:
SUMmARY
Treatment Flow Rate, cfs
Cartridge Flow Rate, gpm
Number of Cartridges
Determining Number of
Cartridges for Systems
Downstream of Detention
CRH
611912013
evs Pharmacy
Washington
Renton
3.01 ac
0.47 ac
2.54 ac
1.98 ac
0.56
78%
0.75
0.30 cfs
0.08 cfs
50%
36 In
80%
90%
224,521 ft'
70 mgn
980.551bs
Storm Filter
12 In
1.0 gpmiff
490.281bs
490.28lbs
0.60
294.171bs
5.00
24.001bs
13
0.14 cfs
8
MASS-LOADING
0.14
5.0
13
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FRAME AND COVER
IDfAMETER VARIES)
N,T.S.
I. CONTlCH 1tI f'IItOWIEAU. Wl1ERW.IlH.E88 MDTm D'MRWIE.
2. DIIIEM8IDIIIII WoAICEDwrnt( )AREAEFEfIENOE l*ENIIOHI. ACTUALDMMIIONII .... V 1HIIt'(.
BYPASS SllWC11JR£I&
1 fQRsrtElI'ECIFIC~wmtllETNLm'INA.T~"'W&I~Pl.EAECGMTAtT't'OURCONMCHENUlEEREDsoumONS lJ.CNiJllllllEll9lTAlWE. _....-...e&_
... fltIMFI..1Bl WA1Bl aLW./1'I' ~ aw..L lIE 1M UlCDRlIIINICIE NTH AU. OEIIOfIIIMTANIIO ~11ON CONT.-.BI-.llMIS .........
I, InRUCTURIE atW.L.1IEET MIIHfD Hall U»D IVoTlNB, AAL.MINCI ~ COlIER Of" ... NfljGftQl.JllDW,tllTER B..EVATION AT. CI1II ~, THE
0UTI.EI'...e IH\IBlT ELl!VAlYIN. eNdN!J!lll twA£OOlllD m CONFRiI ACTUAL GRfKHlIWI'.TER E1.£W .. llOH. CMTINGS8Kl\U.tE£T MSHta
MaRCIE CMTwmt n. ClDHTKtt LDQCl
L FI.~ CMnIIIX/IIEIi MWJ.IE III&IM.R.LED, I'M8I11E,. IIPHQN ACnMTm, RADIAl. R.DW, Nflj SB.F ~ RADIAl MEDIA D£PTH SMAlL
E'-IIIICMB. I'lll'ERMEDUllaJNTM:TlWIIIIE-u..'''TLBMT.~
7. BPECFlC R.DW RATE • EQLW. TD nE FlLTBI Tl'EIIlIIENT CNI'ACITY _, DMDED.., T1tl FLTEII: COHToI\CT IlIRI'I\l:& NUiA I ... II)
(1I!!IIf1 .,.....,., "'"'""I ~ r-"1
SFMH96
STORMFIL TER
STANDARD DETAIL
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6.1.2 ENHANCED BASIC WATER QUALITY MENU
6.1.2 ENHANCED BASIC WATER QUALITY MENU
Where appUed: The Enhanced Basic Water Quality menu' is applied where an enhanced level of
treatmeot is required for those development sites or portions thereof that generate the highest
concentrations of metals in ,tormwater runoff and drain by surface flows to a fish-bearing stream. Acute
concentrations of metals such as copper and zinc in streams are toxic to fish. For precise details on the
application of this and other water quality menus, refer to Section 1.2.8, "Core Requirement #8: Water
Quality."
Note: The Enhanced Basic menu is a stand-alone menu. It integrates the Basic menu level of protection
and the additional measures needed to achieve a higher level of metals removal. When this menu is
required In Basic WQ Treatment Areas per Section 1.2.B.I-A of Core Requirement #8, it is intended to
replace the Basic WQ menu on development sites or portions of development sites that generate the
highest concentrations of metals in stormwater runoff When this menu is required in Sensitive Lake WQ
Treatment Areas per Section l.l.B.I-B, it is intended to be combined with the Sensitive Lake Protection
Menu such that afacilily design option common to both menus must be used.
Treatment goal: The Enhanced Basic WQ menu is designed to achieve 50 percent total zinc removal for
flows up to and including the WQ design flow or volume (defined in Section 6.2.1, p. 6-17).'
Basis: The treatment goal is expressed in terms of total zinc removal. Although zinc is not the most toxic
metal in stormwater, it is usually present in significant amounts, making it a practical and ",liable
indicator of overall performance. Many metals are readily adsorbed onto particulates in the runoff,
usually the finer fraction of the particulates. Facility combinations that remove more of the particulate
load than the Basic menu, including the finer fraction, are specified by the Enhanced Basic menu.
Facilities providing organic binding sites that enhance metal adsorption are also specified.
tJ ENHANCED BASIC OPTION 1 -LARGE SAND FILTER
This option includes use of. large sand mter, large .and r.lter vault, or large Unear sand IiIter. Sizing
specifications for these facilities can be found in Sections 6.5.2 (p. 6-104), 6.5.3 (p. 6-123), and 6.5.4
(p. 6-129), respectively. Note: A presetlling cell is required if/he sa1ld/ilter is 1Iot preceded by a
detentionfoC/lily.
tJ ENHANCED BASIC OPTION 2-STORMWATER WETLAND
Provision ofa stormwater wetland (see Section 6.4.3, p. 6-89) or <ombined detention and .tormw.ter
wetland (see Section 6.4.4, p. 6-95) satisfies the 50 percent zinc lIlmoval goal wilbout additional
facilities. The large amount of organic material in the stormwater wetland provides organic binding sites
and is considered very effective in removing metaJs.
tJ ENHANCED BASIC OPTION 3-TWO-FACIUTY TREATMENT TRAIN
This option uses one of the basic water quality treatment options listed in Table 6.1.2.A (p. 6-8) followed
by a basic sand filter (see Section 6.5.2, p. 6-104), sand filter vault (see Section 6.5.3, p. 6-123), linear
sand filter (see Section 6.5.4, p. 6-129), or StormFilter with CSfTM lear compost media (see Section 6.5.5,
p.6-134).
3 The Enhanced Basic we menu targets different pollutants than the lake or bog protection menus. It does not necessarily
provide a higher level of lrealmenl except for the targel pollutant, metal conlamlnanhl.
.. This goal assumes total zinc concentrations for untreated runoff are between 0.10 and 0.25 mlillgrams per Hter ImlL). For
projects that are expected to generate higher levels of metals, such 8S a mining operation, a higher trealment goal may be
appropriate.
2009 Surface Water Design Manual
6-7
SECTION 6.1 WATER QUALITY MENUS
'r ABLI!l6.1 :2.A
PAIRED FAOILITIES FOR ENHANCED BASIC TREATMENT TJtAIN.OPf10N's
First Basic WQ Facility: Second WQ Facility:
Biofiltration awale (Sections 6.3.1. 6.3.2. and Basic sand filter or sand fllter vault (Section 6.5.2
6.3.3) or 6.5.3) or StormFilter with CSF (Section 6.5.5)
Filter strip (Sections 6.3.4 and 6.3.5) linear sand fliter (Section 6.5.4) with no
presettling cell needed
Linear sand filter (Section 6.5.4) Filter strip (Sections 6.3.4 and 6.3.5)
Basic wetpond (Section 6.4.1) Basic sand filter or sand filter vault (Section 6.5.2
or 6.5.3) or Storm Filter with CSF (Section 6.5.5)
Wetvau~ (Section 6.4.2) Basic sand filter or sand filter vault (Section 6.5.2
or 6.5.3) or StormFliter with CSF (Section 6.5.5)
BasiC combined detention and wetpool facility Basic sand filter or sand filter vault (Section 6.5.2
(Section 6.4.4) or 6.5.3) or Storm Filter with CSF (Section 6.5.5)
Basic sand filter or sand filter vault Storm Filter with CSF (Section 6.5.5)
(Sections 6.5.2 or 6.5.3). A presettHng cell Is
required If the sand filter is not preceded by a
detention facility.
Storm Filter with ZPG (Section 6.5.5) Basic sand filter or sand filter vault (Section 6.5.2
or 6.5.3) or StormFilter with CSF (Section 6.5.5)
1.'92009 2009 Surface Water Design Manual
6-8
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APPENDIXB
OFF-SITE ANALYSIS FIELD INSPECTION PHOTOS
c-------10660 SE 176th Sreet, Renton, WA
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is rot refelWllCl on y. o.ta aay.,.1hIt ~ .... Of" II. InIIP nta)' or may nat be
ec:cur.Ie, wnent. or otherwiIe IIIlabJ •.
THIS MAP. NOT 10 BE USED FORNAVIGATION
----....... ....
1019
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2of9
OFF-sITE ANALYSIS DRAINAGE SYSTEM TABLE
SURFACE WATER DEsIGN MANuAL, CORE REQlliREMENr #2
Black River Watershed
Basin: SubbBBiD Name: SubbBBiD Numbel":
Symbol Drainage Drainage Slope Distance Exldng Potential Observations of field
Component Type, Component from site Problems Problems inspector. rasource
.... aild Size n ~r or .. ldent . :
see map Type: __ ._. drainage beIin •• ~ .. '" 14 mI c 1.320 11. wtlllbIClluis. under~. pandkoIg. trI>uImy -. _ ofprDblem.
SIJaaIII. Channel. pipe. aMJr. depIh. type of IHII1Iitiw _kippl,.,. -D. habitat or arganIosno --paII,_. paIBntiaIlmpads
pond; Size: dianototoIr. ...... """""" _.1aIIIIing, bmokllaughing.
au_area
tnaaIcIo __
CD t-6 rtll; 1-See Map See Map None None S~:£""""'T 7.H ... 1'1" ~ 1. '.ffI~ ., • ..., (i) goo l.ooIJ(,. M ,...,. "-T~.""F""'"
@ (41l0~[, P:t.-n.1f IIf:f4;1'A7'ZD,.J () .. ~
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4 Il." (.,d,.J~ P'lIE
~1/f:eT R..6 ..... '. --:!. AMI ">00.,'" 'PaUli' WI 'D )sTc/f
® ~/IJ)SXIE ~1'~ V~J,,'T~ .~N .1, !Asr-f ,.-JII!!:8/!. :Z;j" .,."..
a> 1'2:' HIlPE: ~fb
-t ~,,J I", o.lIU" ~6At).sJOeo ~~ 'i '--"rs.i~
ITs" c.nP ~ ~~",,",.
® ('8 ~ ~.!!-.IL
ai) 16" l..otJc" PIPE.
t C.13 UNt.I(erE :z,J1E:bDll ~6__ UIolD~"lltI,JC:
15"cON{, P;r.Pa
® c8 ._ 7JUT~~
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(!J_ . 18" CA,J~ n.fE. ,
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CarrlBenson Velmeir Retail Pharmacy
<lFF-8lTE ANALySIS DRAINAGE SySTEM TABLE
SURFACE WATER DESIGN MANuAL, CORE REQUIREMENT #2
3019
Basin: Black River Watershed Subbasin Name: Subbasin Number:
Symbol
_map
.,.. _til_WID'
Component Type,
u ___ • and Size
Type: sham !law. _.
stream. Channel. pipe.
pond: Size:_ .
ourfaoamaa
@ c.e
@ 18" cQlJc. PIPE
..,1 __ . ___
Compona ....
n--~''''''
e -. II8gIIIII
...... depth. type of_. .... -
1"yl'6 :L (1)
Slope
%
SeeMa~ ,
from site
Oft.
See Map
Existing
Problems
_.-..01.~""""'"
Problems --...-. '-g.-:ouring, -.. - -sadb 'Wi dIIticH I. incIRJn. alta ertIIIkm
None I N~ne
"IS of field
Insoeclrcir. resource
_ ',01'
1ribuI8ry .... __ of prtlb8n. •
__ pathways. paI8n1IaI impacIIi ~'.'
t
;
l ]m~.e~.»~~'1rlli&~&~~~pP-ei.;~~!~~iE=ir1·
..,... US Itr (...e.ISrG, (!1.!1!
~
IM"r I: I~.. PlP6 I nfe 2, qS" I I I "I I I I~'o 1
@ I t.6 oR. M# 'T" ~"'''VII" ~
@) I "J..Cf" f1.fE;
'"Til R/1i11"11N6 I&IJ I =-I ::u ~lP:H I I I I II I l I I I
r.:i:t _l.I. $'1.ea.t11l1lB' ~_ IJ/'J I IeJ7 t.6 64 '-rrr I -"BI' 'sI.oIP.! ~ . -
J "
. I @ z,,/" PIle T'
r.;;.. IM.e .. ·.., .. -~_7eD ~,J
18!1 ceo 0It. MH $1<1 flue wHPM) /IrIIIIIt, ~A""~'" """"D,
r.::.. ..... _Ul 'to q,., .. " I!.!I &6 ,.,. IttP"A/lbJ't" PCA",4De
P:de
e ",0 ~"'T P4 .... 'to> ",,4a.e 1/ 1'7-I'e ~foJl/IIZ. S w/IrUC. 11 A t»IJ"'Itt;:r r.. ;J.Te,I'\
tl "AlAI«&-or. b-16 I/UJ t.~ Hl. nu 111() N6f .. lI""un Pz!IJ I _n.. 70 _ .... _,##~.~
1/912009 '13,] tt.",d l,",,'l'l' Il!mllllI _ .. __ _ ~ __ ...... _ _ _ _ _ ....... __ _
~r/BPn!on 'ftfme~etam,armacy .. .. IKl .. .. .. - -
.. .. _ 1I!II . .am
OFF-8ITE ANALYSIS DRAINAGE SYSTEM TABLE
SUBFACE WATER DESIGN MANuAL, CORE REQUIREMENT #2
4of9
Black River Watershed
Basm: SubbasiD Name: Subbasin Number:
Symbol Drainage Drainage Slope Distance Existing PoIaIItiaI Observations of field
Component Type, Component from site Problems Problema IlisptII Ii •• resource
Name, and Size " on e ~r, or resident
see map T-= __ .-' dnIinage baIin •• ...-,.,. % 111 mI ~ 1.32D ft. =-ana. ..... capacity. pancing. Iributary ..... __ allX1>bIem. _. cIt_. pipe. C<NeI'. dapIh.lype of'-o.a bJppii "'" ftDading. habitat Dr organlarn -flIIII-ys. ~ ImpacIs pond; SIm:_. ....volume --. acaurtng. bank oIaughing.
oulfllcearaa BilIMIL'" I Indaion. aIher IIf'DIIlan
® swALI. "'~A$!. ,,~ See Map See Map None None MA':W7"1o:1."'e:1>
® /7)' ""~(., P-SP(;
@ t.&
S IV' fAlle. hfJE:
~ /l.oArPS'U)f,: ~ "IEM!TA7z.~ O"::~"i,.SVfi:6ert'JtT2""
~ 12,." UJl,Je. PtPe (.MJII~ 11J eIJ I "'T~
@ C8
IV \ V I \ ,
_._-
1N2OO!l
I
leaves and enters on south side of SE 1
debris/garbage in ditch and overgrown vegetation.
Roadside ditch enters piped portion of downstream system at southeast comer of SE 1
SE.
5 019 t
PI SE. Note
PI
[
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Piped portion system
photo located at southeast comer of SE 174th St
interior side.
Piped system crosses to comer
the right side of the roadway in the right photo.
60f9
S 36th PI appears to be missing some bricks on
PI and drains down steep
7019 [
Photo on left is looking back up at SE I St (and 1 Ave piped system located in a
grassed area on the west side of 103'" Ave SE and is routed to the left of the photo down a steep slope.
Photo on the right is looking at bushes before drop off to steep slope.
M!IDDOle covers the system on were not system appears
to outfall into a wooded area beyond the Y. mile flowpath based on City of Renton GIS maps.
~
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8019
Stormwater discharges from southwest portion of site through catch basin and 3" pipe under sid,ew,.Ik.
Site discharge from upstream appears to to a grass swale.
Connections from upstream components either the catch basin shown located upstream of a grass lined
swale or outfalls to the swale directly were unable to be confirmed because catch basin cover could not be
removed and pipe outfalls were not found. Note flow of water in swale.
Overgrown to system along
shown above in Group Photo No. I through a catch basin located in southeast corner of SE I
106"' PI SE.
9019 m -')
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APPENDIXC
BOND QUANTITY WORKSHEET
_________ ....... _______ 11\!_1l t..;;:.J L--.J
-.
Site Improvement Bond Quantity Worksheet
~ ..
Right If WIIlJ
1--unIf
_1IiiIiiIC
I a otMdlmpro,.:* iE~ A==
"""* Imprv
"""COiif
2 of7
&!T
COot
_
'liii:"
BllcIdID& om.......... GI·l S----.:B2 CY 10 SI..'l.O _ 10 J>,~.'t"' ..... '$0 I.I_._,~ __ _
1_&CGmpocllon-_ GI·2~_ B.Ii3 CY 0.00 10 ~:r~ -.so --,"1"'"1..~_ 1 0.1
GI· 3 S D.3B BY 0.00 0.00 0.00 -•
GI· 4 $ 8,816.18 ,... 0.00 0.00 0.00
• bulk GI·' S 1.60 CY -m 0.001'" 00.:> "coO,""" ~ ---Itiii GI·8 I 4.UII CY ,.. ~_O ~l.OQ~ '000 .!!.o~O,:.!i
• • Gl· 7 S 18.1511 LF O]i 11,!
~'\' IGl·8 $ 13.<14 LF' ~ '"iii 1015 'I'L)'!, 100 -II.
• • • GI·.! $1.271.8 _ II.IX O.uu u.uOi i ~UilJ
~ • ",·1 i. 12. 1~ LF 0.00 0.0. '!:!!!!L.J. 0.110 ~ .... pact.comman_ ~I·ll S 22.57 CY to 1 .... '"OJi, 0 "l:U5."".~ ICOO 1.1.
IFIU .... ~-·1 • 2S.48 CY 10 'U_'t·Jo .10 ~-I'"'U L2.'--'-~!!1
.... IDpoaII 1·1, S 37.85 CY" 11I"I.U S '''''1.= fl.., ],\'1<1."0
1·1 S 54.01 BY O.OD 0.001 0.
1·1 I' 74.85 BY 0.110 0.001 O.uOi i u·uilJ
~ 1·1 I. 1~ BY II.w 0.001 O,~.j. 0.00
•; ~t1and ",1.1 $ iB BY ~ .">-10 ~!:' loolO ........ J:Q:!' "'.!:!: \Lt,1" I· 1 $ o'li BY 0.00 0.00 '2..iG:
• 1·1 1$ 136." Eac:h 0.00 ~ ~
I!
Sol"'.,. 114 __ I GI-2 S 2.88 Each 0.00 0.00 Q,
-. o:z::::::
~·2" 7.411 BY ''5'' 111.,\0 _ IT ,\t."" ·~SO "1.1011.00 -""""-J u.uilJ
~ L!. 788.26 ..3. ~ O.~ O~.J. '!:£" ~ iiiiii" r-0.0 0.110 0.00 0.110
85.18 HR 0.00 0.00 0.00 0.00
7'" SY 0.110 O.OD 0.00 0.110
8.33 BY 0.00 0.00 0.110 0.110 ip: I: ~81 BY MOl 0.
110
1 I 0.001 0.001 tl: : &gg ;,s>, )tt.". if ~% ~:gg 1131
Paga2 of7 SUBTOTAl. ~'\'."IS' _ S}b"I. IS" IIoII\t'
REF 8-H BOND QUANTITY WORKSHEET.>de
Iv l!'!irlr. ....,.
10 '001...10
0.00
UnH prIcea updated: 2112102
V8IBIon: ifIZ2/02
Report Date: 1/1912010
_ _ _ _ _ _ _ _ _ _ _ I!!II!!IIII _ _ /!c::i!f%c] c:::::J
3017
Site Improvement Bond Quantity Worksheet
I
cC=:~t=!;
.IMPR~No. c~ c
OIfndIng,4' __ <1 IRI-23.00 BY
,' __ ' RI-2 5.76 BY
~->2IlODoy
RI-3 .38 IIY
lAC I RI-4 41.~ BY :3.$0
liiirl RI-5 :ii L.f
I I;Wle UI ( Pa,,_ueut RI-a L.f
Curb & Gubr, IDD8U RI-'3.27 L.f
~& " ><i-e , 8. .... 'tIS"
~""_,don_""~RI-8 1 , 13. LF
,amuded uphoIt ~-11 , 2-LF
I~UIb, __ """"'" ~-$ 2M LF 3-_ ~-, $ 1.111' LF 2..,,,
BawQ4,-. RI-' 1.118 LF
BeaIant._ -~1~ o.~ LF
SllaUIdor, All. (_ AC IOIId unit prtce 1-1 -BY 1'---., $ 7.63 BY
.""""" '-1 It 30.52 BY
4-I deIrdtIan and .. 1 c, V.73 BY _~i __ :!:1 b
, I 34.84 BY
34.85 SY
,honllCOP RI-2 85.2B EIoh
JSbIPIng, por .... ",-Zi 5.82 1-r=ilhonnoplullc, for "'---'" • 2.3B SF ,4-,_ "'-'" ,
1'11110 3 017 SUBTOTAL
REF 6-H BOND QUANTITY WORKSHEET Jda
..... ng r_",,!,iC c ,......a _-...tIoft"
RIght~
& .... ~=ts c ' ........ a: , ..
e c_~J
Caot
cC
0.00 0.00 0.00 0.00
u.00 u.uu o.uu 0.00
u.DO u.uu 0.00 0.00
Oz. ,00 ~ ~1"1.',"·"" ... 0112.0 'l-1f~114.CJD __ 0.00
~ 0.00 u.oo ! 0.0 ~I:ti u.oo 0.00
"O"l.I.'),~ """" IS-IltS. U_ ... ~~"-'l 11'1
0.00 ~ 0.00 u.oo
u.oo O. 0.00 O.W
0.00 0.00 u.oo 0.00
5'.,.", -. o.w 0.00 0.0Il
0.00 • .uu 0.00 O.DO
0.00 0.00 O.!JD 0.00
i I 0.00 0.00
2."'''I ... J(.l~ 0.""
&; 1111.1"1. ,0 0.00 0.00
~ ~ '1.10.)0'1 -u.uu O.uu
0.00 0.00
0.00 0.00
0.00 0.00 ,
u.uu 0.00 !>
1$0"1.0 .11 -'Obl"Vn __
0.00
'II. I'"\. 0.00
4-01_511 ::1 \ 1"1.60 0.
4r:.O'lS'l.SI_
0.00
0.00
~ •• 1
0.00
Unn prices updaled: 2f121D2
Version: 4122102
Report Data: 111912010
____________ I!iI1I1iI P",q L.J L-lJ
Site Improvement Bond Quantity Worksheet
,~ ............... , ~
\ ~ .... at.., "*'."+'. Ita ..... ". I
~~ & ' F1IOiJiiIi. ,
:!iI'" , .1
IAOIln~ "_. " ,&
IFor J<CRS '113, 2.6" !t,RS-1 3.80 BY ~I ~ ~ ,1.5" RB" 1.311 BY
,'Z'#«; RS· 8.15 BY 0.00 0.00 0.00
IACRoad.'Z',4".-, ~ ~·4 .. '1.24 BY 0.00 't'LI ")1.l>'II.OY ..... 0.00
'IACRoad.'Z',4".-,QIV.CMII' RS. $ ~ BY 0.00 0.00 u.w
lAC RaacJ. ,', "''-' R1II2500 IRS· BY 0.00 _ 0.00 3",4"'-' QIy. CMII' 2500 BY IRS· 15.81 BY 0.00 o 0.00
IACRoad. ,FirBl2ouu "y I .... • 14.57 BY .II'> ,1.0'\ ."1.1 ....... 1"5 'I '" S "I.1.l lAC Road.Ii', QIV. a-RS· 3.84 BY 0.00 S, ~.n-.
lAC Road, 6"~BY -1 18.78 BY O.uO 0..., 0. ..
lAC Road. 8". • a-2500 BY -1 18.12 BY 0.00 0 . 0
........ TntII8d ,4-$ 8.21 BY 0. 0.00 El' 26110 BY
$ 1.4' BY D. 0...,
RaaeJ. 4".-, QJy. _2500 .. Y ~-1
• 1.53
BY 0.00 0 D.uu
C Road. F. no , aver 2600 BY ~. $~ BY
tK
0.00 0.00 0.00
IPCCRaaeJ,8".naboae,CMII'2500BY lUI· 1
• 21
BY 2."1'" . n. .-:!! 0.00
1"'-• 1.1' o.w O.UIJ
Pago4af1 SUBTOTAL '1'1 n. b~ IIoJlO. '1>117. b, _ S(" 01.0. ''I o.e&o
REF 8-H BOND QUANTITY WORKSHEET.xI.
4 of7
Bond .......... • ,
_QuInt. I
CGIII :
,
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
UOW
0.00
Unit prices Updalad: 2112102
V .. 1an: 4122102
Report Data: 1/1Il12010
I
- -~ .... ___________ 1j!!""::!1 tr'!'~l (',~J
Site Improvement Bond Quantity Worksheet
"-RIght of...,
f_1iiiIiIIi 1J:7 IU
... --
""*'
..... 0 •• ' ...
"""'Ciiif
'CPP: ,_-,...... Farc-t_. _.,4'____ M
5of7
Il:iiOnI. ""l
Coat 111_
__ .RID D." 6.74 SY 0.00 0.00 o.DD 0.01
._ D· 2 $ 20.14 ...... O.DD 0.00 0.00 0.01
._ D·3 , 4"~ -. 0.00 0.00 0.00 Q.O( 0(C8a~
CB nPel D· 4 $ 1,257.84 _ 0.00 0.00 0.00 0.001
CB TWIelL ·5 i ijD'.58 Each a.oo 0.00 I I Of n. S"I ....... o.oo(
CBTWlBn..... D·8 ,to3im Eaoh I "Z. .. )~.~-, Il:OO I -l."rn.S"1 0.00 I 0 ~03l;S.-,~ 0.00
foraddHlonaldoplll_4' D·7 438~ FT ~ \lo'l.S4 .... O.oo~:s '2.' .~ O.DD
~BType~". metar D·8 ~2.182.1i4 Eaoh o.DD O.DD 0.00 0.00
for a dapIh _ 4' D. B FT 0.00 O.DD o.DD O.DD
BTl'JI8n. _ D·l0 1.52 ~ o.DD O.DD 0.00 0.00
lor do"", _ 4 D· II ..... 54 ---.r O.DD 0.00 0.00 0.00
C I D. 72" D· ,2 ~ _ o.DD 0.00 O.DD D.O[
...,_-.~~-•• D·13 $ ~ FT 0.00 O.DD D.DD O.D<
D· 14 , 388.DB Eaoh O.DD O.DD o.DD D.DD
D· 15 I 13D.55 -. O.DD 0.00 D.DD 0_00
~~PVC.II" Do'S S '74.80 -. 0.00 0.00 0.00 D.DD
.11" D .17 $ 224.18 ..-0.00 or: 0.00 0.00
uIwtIt. PVC. 4" Do 18 $ 8.84 Lf 0.00 ~ 0.00 O.W
~UIYerI,. pvc. 80 D·1 $ 12.80 L.F O.DD 0.00 0.00 O.DD
, II" D. 20 $ ,3.33 LF 0.00 WIll 0.00 ~12" D· ~ 21.n LF 0.00 0.00 0.00 u.uu
CUIvort,ClI:ii!: 8" Do 22 $ ,.;:~ LF D.DD 0.00 D.DD D.DD
....... CMP. 12 D· 23. 28-:4 Lf D.DD 0.00 O.DD O.DD
• 15" D· 24, 32. LF D.DD 0.00 0.00 0.00
~CMP. 18" D·25..!. 31;!.4 ..!:!:. o.DD ~ O.DD 0.I!2J
r;::::::::; Ig:~I: ;:::1 g I rcJll gil ~ool g.m
Page 8 017 SUBTOTAL J~'1). l'!l ~ 2.O'!o).SJ ~ )-'O'n.'i'I_ 0.00
REF 8-H BOND QUANTITY WORKSHEET .xiI
UnH ptc:as updal8d: 2112102
VersIon: 4122102
Report Dale: 111912010
____________ ~fifr1fi5';!lc:-:J
60'7
Site Improvement Bond Quantity Worksheet
"~ F__ . _ _.
"&. II~n -81:4 lit eo.) R..a .... ' $ ..... 0 ... ..
. I unot PnCo UIIII QuonL & ~ -...... -QuonL.1 Coot
~1RwrI, Cononda. 8" D ~ ,
IQII'oIWt. 00_. 12" 0 -33 I ..,.... LF _ 0 C
CIIWrt. ConaraIII. 15" D • 34, 37.34 LF 0 0 0 C
~'.,rt, CanonIa. 8" D· 36 I ... .51. LF 0 0 0 C
LIhIIIrI. Cononda. D • 38 I 81.or. LF 0 0 0 C
CUIvort,ConcreIo. D-37 S 04.18 LF 0 0 0 [
WIV8I1. D· 38 I 137.83 LF 0 0 0 [
CUlVIII,CanonIa.42" D-39 , 1_ LF 0 -'
CUIvort, CCInoII1II...... D· 'IQ I 75~ LF 0 0 0 {
CUIvort, cpp. 8" D-41 , O. LF 0 0 0 {
uIvon.CPP.8· D·42 I B. 0 LF 0 .C "IS" In'l.SO 11 I
WVtIII, CPP.12" 0·43' 20.10 LF I ~C'l "I _~_ .. 0 ,SS" ~r."Uo so 11 [
WWR,<lPI'.1... 0·44, 23.00 LF 0 0 0 I
....-. "",p. 1.... D· 4Ij' 27.80 LF 0 [ ICiiViii: "", ... 24· D • 48, 3B.BO LF 0 0 0 [
~CPP. D-47' 048.30 LF 0 0 0 [
D·48 $ 8.08 r::t 0 0 0 [ ~CPP.38" D-48" .... 20 LF 0 0 0 I
AM ==~~~~~('~~38~~~~~~~D~~ '-iaM»8=+~LF~+-__ -4~ ________ ~ __ ~ __________ ~ ____ +-________ .r ____ ~ ________ ~
F,.,chDraln ("'_, ,0·51,' 22.BO LF 0 0 0 I
.18KI1n-'~"" D·52 I 2.40 Sf 0 0 I
pond D·83 I 74.75 HR 0 0 0 I
IMId ___ .4r .... 8'deap D·54 11.B05.4O I Each 0 0 0 I
EliS ·55 I 14.01 SY 0 0 0 I
• 12" D • 58 1.045.18 Each 0 0 0 I
lor. 15" D· 671.085.58 Each 0 0 I ~~~OD .18" D::! .1048.18 Each u 0 I
" ~ D~~ S 39_ r::t J't 1''1"1 I~ .... 1'1 S".,.n."1I 1
""'!.~ D· 11.000.50 Each 0 0 0 I
IlUh RIIdc, 12" D· S 21.9 0 0 0 I
_ RIIdc, 15" D· 82 $ 237.27 Each 0 0 0 I
-RaGle, 18" D· B3 $ Z1IIIJI8 ~ 0 0 0 1
TIIIIII ....... 21' I.... EriiiIf
Page 8 ofT SUBlOTAL 'SH."n ......
REF ~ BOND QUANTITY WORKSHEETJda
o IIJ 05.1'" + o
Unit prIcea updalad: 2/12/02
V_Ion: 4I22ID2
Report Da\a: 1/1Il12010
-----------
Site Improvement Bond Quantity Worksheet
..;..-.;;~
fWn_ -RaMI ..... o •• ,... ,,' hl .. o .... I.
I !UIIIP_ UM
~ ......
LJ CIIII 0-0. I cc.
AC. ~ ....... .-& 4' _ Jt:': 1 I 15.84 SY 0 0 0
AC,1.5"lOP ...... & • .6"bue .... IPL· $ U.24 SY ~'11o I.l-5 S 105" 11-'_~ Pl.-3 $ 4.65 SY 0 0 0
1.6"1ap ...... _&~ ........ 1 ..... 4 $ 11.41 SY 0 0 0
~ -,
U .. A •.• ~ Il,,,, •. ~.-... ~1 IIO<U "'" Eoc:h • 0 0.00 • . ,,!>OOOO~~
-2 IIY 0 O.llll 0.0
-3 CY 0.00 0.00
WI-4 LI' 0 0.00 0.1J1l
P .. ,.. WI-5 ,~ "T OlltllO I SIocO 1liliiii D..,.
WI·a 0 0.00 0..,.
WI-7 0 0.00 0.00
IWI·e 0.00 0.00
IWlo·g 0 0.00 ]! ... 10
SUBTOTAL 0.00 I~Q!l2 o:tIIt bi~L~.l\a..
SUBTOTAL (SUM ALL PAGE&): z.',2Y> • 'I" D:1I9 '-II,Il'! .5" MIl n 1. ~t7.\~· (~ , .
_ CONllNGENCY & 1II01IIUZA1lON: ~110.o<f 0.00 1J..,!'"IO.1'7 0.00 '1' ",'1S1 .~'Ne-
GlWIIJ1lJTAL: )~'f 01. ;0 0.00 51 ~'<I. '1) 0.00 (J "1.J,.11.'~
COWIIN: ; B
,
C
, to
Pago7017
REF II-H BOND QUANTITY WORKSHEETJda
__ aD c:J
7017
BondA I r:tlan-
au..t.l ....
Coot
0
~
~
0.00
O.
O.
0.
0.00
0.00
0.00
D."
0.00
0.00
0.00
0.00
E
UnIt plfcae upda1ad: 2/12102
VenIIan: 4I22Al2
RepoIt Dlllr.1I1B12010
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I
I
APPENDIXD
DECLARATION OF COVENANT
.,
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RECORDING REQUESTED BY AND
WHEN RECORDED MAIL TO:
CITY CLERK'S OFFICE
CITY OF RENTON
1055 SOUTH GRADY WAY
RENTON, WA 98057
DECLARATION OF COVENANT
FOR INSPECTION AND MAINTENANCE OF STORMW ATER
FACILITIES AND BMPS
Grantor: ____________ _
Grantee: City of Renton
Legal Description: _________________________ _
Additional Legal(s) on: ________________________ _
Assessor's Tax ParcellD#: _______________________ _
IN CONSIDERATION of the approved City of Renton __________ permit
for application file No. LUNSWP _________ relating to the real property ("Property")
described above, the Grantor(s), the owner(s) in fee of that Property, hereby covenants(covenant) with the
City of Renton, a political subdivision of the state of Washington, that he/she(they) will observe, consent
to, and abide by the conditions and obligations set forth and described in Paragraphs I through 10 below
with regard to the Property, and hereby grants (grant) an easement as described in Paragraphs 2 and 3.
Grantor(s) hereby grants(grant), covenants(covenant), and agrees(agree) as follows:
FormRcviscd 12112106 I
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I. The Grantor{s) or hislher{their) successors in interest and assigns ("Owners") shall at their
own cost, operate, maintain, and keep in good repair, the Property's stormwater facilities and best
management practices ("BMPs") identified in the plans and specifications submitted to the City of Renton
for the review and approval of permit(s) #: . Stormwater facilities
include pipes, swales, tanks, vaults, ponds, and other engineered structures designed to manage
stormwater on the Property. Stormwater BMPs include dispersion and infiltration devices, native
vegetated areas, permeable pavements, vegetated roofs, rainwater harvesting systems, reduced impervious
surface coverage, and other measures designed to reduce the amount of stormwater runoff on the
Property.
2. City of Renton shall have the right to ingress and egress over those portions of the Property
necessary to perform inspections of the stormwater facilities and BMPs and conduct other activities
specified in this Declaration of Covenant and in accordance with RMS 4-6-030. This right of ingress and
egress, right to inspect, and right to perform required maintenance or repair as provided for in Section 3
below, shall not extend over those portions of the Property shown in Exhibit "A."
3. If the City of Renton determines that maintenance or repair work is required to be done to any
of the stormwater facilities or BMPs, City of Renton shall give notice of the specific maintenance andlor
repair work required pursuant to RMC 4-6-030. The City sha\1 also set a reasonable time in which such
work is to be completed by the Owners. If the above required maintenance or repair is not completed
within the time set by the City, the City may perform the required maintenance or repair, and hereby is
given access to the Property, subject to the exclusion in Paragraph 2 above, for such purposes. Written
notice will be sent to the Owners stating the City's intention to perform such work. This work will not
conunence until at least seven (7) days after such notice is mailed If, within the sole discretion of the
City, there exists an imminent or present danger, the seven (7) day notice period will be waived and
maintenance andlor rep'IIir work will begin immediately.
4. Ifat any time the City ofRenlan reasonably determines that a stormwater facility or BMP on
the Property creates any of the hazardous conditions listed in KCC 9.04.130 or relevant municipal
FonnRcviscd 12112106 2
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successor's codes as applicable and herein incorporated by reference, The City may take measures
specified therein.
5. The Owners shall assume all responsibility for the cost of any maintenance or repair work
completed by the City as described in Paragraph 3 or any measures taken by the City to address
hazardous conditions as described in Paragraph 4. Such responsibility shall include reimbursement to the
County within thirty (30) days of the receipt of the invoice for any such work performed. Overdue
payments will require payment of interest at the current legal rate as liquidated damages. If legal action
ensues, the prevailing party is entitled to costs or fees.
6. The Owners are hereby required to obtain written approval from City of Renton prior to
filling, piping, cutting, or removing vegetation (except in routine landscape maintenance) in open
vegetated stormwater facilities (such as swales, channels, ditches, ponds, etc.), or performing any
alterations or modifications to the stormwater facilities and BMPs referenced in this Declaration of
Covenant.
7. Any notice or consent required to be given or otherwise provided for by the provisions of this
Agreement shall be effective upon personal delivery, or three (3) days after mailing by Certified Mail,
return receipt requested.
8. With regard to the matters addressed herein, this agreement constitutes the entire agreement
between the parties, and supersedes all prior discussions, negotiations, and all agreements whatsoever
whether oral or written.
9. This Declaration of Covenant is intended to protect the value and desirability of the real
property described above, and shall inure to the benefit of all the citizens of the City of Renton and its
successors and assigns. This Declaration of Covenant shall run with the land and be binding upon
Grantor(s), and Grantor's(s') successors in interest, and assigns.
10. This Declaration of Covenant may be terminated by execution of a written agreement by the
Owners and the City that is recorded by King County in its real property records.
Form Revised 12112/06 3
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IN Wl1NESS WHEREOF. this Declaration of Covenant for the Inspection and Maintenance of
Stormwater Facilities and BMPs is executed this __ day of ________ • 20 __ .
GRANTO~own~mtheProp~
GRANTO~ owner of the Property
STATE OF WASHINGTON )
COUNTY OF KING )ss.
On this day personally appeared before me:
_________________ ~. to me known to be the inclividual(s) described in
and who executed the within and foregoing instrument and acknowledged that they signed the same as
their free and voluntary act and deed, for the uses and purposes therein stated.
Given under my hand and official seal this __ day of ________ -', 20 __ .
Form Revisecll2112106
Printed name
Notary Public in and for the State of Washington,
resicling at
My appointment expires ________ _
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APPENDIXE
KING COUNTY STORMWATER POLLUTION PREVENTION PLAN
RELEVANT ACTIVITY WORKSHEETS AND BMP INFO SHEETS
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and Other Erodible
Grease)
Treatment, or Disposal of Dangerous
~ WASHING
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A-11 Cleaning or Washing of Tools and Equipment
A-12 Cleaning or Washing of Cooking Equipment
A-13 Vehicle Washing and Steam Cleaning
A-14 Interior Washing Operations (Including Mobile Contractors)
A-15 Pressure Washing of Buildings, Rooftops, and Other Large
Objects
" TRANSFER OFcLlQUID MATEIl.IALS " ,
{
A-16 Truck or Rail Loading and Unloading of Liquid Materials
A-17 Fueling Operations
A-18 Engine Repair and Maintenance
PRODUCTION ANI) APPLICATION
A-19 Concrete and Asphalt Production at Stationary Sites
A"20 Concrete and Asphalt at Temporary Sites
A-21 Manufacturing and Post-Processing of Metal Products
January 2009 King County Storm water Pollution Prevention Manual
you
Sheet Interpret the categories broadly. Numbers A·1 -A-4S
correspond to sheets located In Chapter 3.
Equipment
Building
, OrnER
A·31 Vehicle and Equipment Parking and Storage
A·32 Sidewalk Maintenance
A·33 Swimming Pool and Spa Cleaning and Maintenance
A·34 Keeping Animals In Controlled Areas
A·3S Keeping Livestock in Stables, Pens, Pastures or Fields
A-36 Logging and Log Yards
A·37 Mining and Quarrying of Sand, Gravel, and Other Materials
A·38 Well, Directional and Geotechnical Drilling
A·39 Roof Vents and Fugitive Emissions (Including Dust)
A40 Street Deicing Operations
A-41 Wheel Wash and Tire Bath Operations
A-42 Potable Water Line Flushing or Tank Maintenance
A-43 Use of Soli Amendments on Construction Sites
A-44 Dust Control and Soli Erosion and Sediment Control for
Manufacturing and Other Commercial Operetlons
A-45 Maintenance of Public and Private Utility Corridors and
Facilities
King County Stormwater Pollution Prevention Manual
you conduct this
activity? If so,
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X
January 2009
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Required BMPs for All Commercial Properties
January 2009
MINIMUM REQUIREMENTS
The following BMPs are required !fyou own or occupy commercial,
industrial, agricultural, public, or multifamily residential property
in unincorporated King County.
Clean Your Storm Drainage System
Maintain your storm drainage system by removing sediment and other
debris to prevent the transport of pollutants into receiving waters. The
storm drainage system includes all drains, catch basins, pipes, ditches,
gutters, and flow control and water quality facilities.
Y See BMP Info Sheet 7 in Chapter 5 for details on drainage system
maintenance.
Eliminate Ulicit Connections to the Storm Drainage System
A common situation that can cause severe stormwater pollution
problems is discharge of non-stormwater to the storm drainage system.
Examples are discharges from internal floor drains, appliances,
industrial processes, sinks, and toilets. These are sometimes illegally or
inadvertently connected or drained to the nearby storm drainage system.
These discharges must go to the sanitary sewer system, a holding tank,
an on-site process water treatment system, or a septic system. You must
correct these illicit discharges. If you have any questious as to whether
your discharge is allowable, contact the King County Water and Land
Resources Division at 206-296-1900.
Y See BMP Info Sheet 1 in Chapter 5 for information on how to
check for illicit connections. You can also ask for help from your
local sewer utility. If you find out that your internal drains are
King County Stormwater Pollution Prevention Manual
Required BMPs for All Commercial Properties (conUnued)
improperly connected to the storm drainage system, they will need
to be either removed, permanently plugged, or connected to the
sanitary sewer, septic system, on-site treatment system, or a holding
tank.
Stencil Your Storm Drains
Stencil or apply storm drain markers adjacent to storm drains to help
prevent the improper disposal of pollutants. Storm drain inlets should
have messages such as "Dump No Waste -Drains to Stream" applied
next to the catch basin to warn against the intentional dumping or
discharge of pollutants. If the metal catch basin grate has been cast with
this message, marking the drains is still recommended, but may not be
required unless evidence is found that pollutants are being dumped or
washed to the storm drains.
For more information or assistance in implementing these best management practices, contact the King County
Department of Natural Resources and Parks Water and Land Resources Divisioo at 206-296-1900.
Reader Note: The above requirements are the minimum required BMPs. If these BMP. fail to prevent discharges to
the storm drainage system, you will be asked to take additional measures to correct the continued pollution
discharges.
Klng County Stormwater PollutIon Preventfon Manual January 2009
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Landscaping Activities and Vegetation Management
This broad activity encompasses all aspects ofIandscaping and vegetation management, from small-
scale yard maintenance to large-scale commercial landscaping businesses and vegetation
management programs. It includes vegetation removal, herbicide and insecticide application,
fertilizer application, watering, and other gardening and lawn care practices. Stormwater runoff from
areas that have been subject to pesticide or fertilizer application or extensive clearing, grading or
cutting may be contaminated with pesticides and other toxic organic compounds, metals, oils,
suspended solids, nutrients from fertilizer, and coliform bacteria, and may cause biochemical oxygen
demand.
While not required, consider using the Integrated Pest Management (IPM) approach for pest control.
IPM is an approach that uses an array of methods to manage pest damage with the least possible
hazard to people and the environment. IPM uses a combination of biological, cultural, and physical
practices that can significantly reduce or eliminate the nse of pesticides.
See Activity Sheets A-5, "Storage of Pesticides and Fertilizers" and A-3, "Storage of Liquid
Materials in Portable Containers," Landscaping activities related to golf courses should refer to King
County's Golf Course BMP Manual (see Chapter 6 of this manual for more information).
Note: The term pesticide includes insecticides, herbicides,fungicides, rodenticides, etc.
January 2009
MINIMUM REQUIREMENTS
The following BMPs, or equivalent measures, methods, or practices
are required if you are engaged in landscaping activities:
Do not apply any pesticides directly to surface waters, unless the
application is approved and permitted by the Washington State Department
of Ecology.
Mix pesticides so that spilled material will not be washed to surface waters,
the storm drainage system, or onto the ground. Clean up any spills
immediately. Ensure employees are trained on the proper use of pesticides
and in pesticide application techniques to prevent pollution. Washington
pesticide law requires most businesses that commercially apply pesticides
to the property of another to be licensed as a Commercial Applicator.
Follow manufacturers' recommendations and label directions. Pesticides
and fertilizers must never be applied if it is raining or about to rain. Do not
apply pesticides within 1 ()() feet of surface waters such as lakes, ponds,
wetlands, and streams. This also can include stormwater conveyance
ditches. Remove weeds/vegetation in stormwater ditches by hand or other
King County Stomrwater Pollution Pmvention Manual
Landscaping Activities and Vegetabon Management (continued)
mechanical means. Chemicals should be used as a last resort.
Dispose of grass clippings, leaves, branches, sticks, or other collected
vegetation, by recycling, composting, or burning (if allowed). Do not
dispose of collected vegetation into storm drainage systems, conveyance
ditches, stormwater ponds, or surface water.
Use mulch or other erosion control measures when soils are exposed for
more than one week during the dry season or two days during the rainy
season.
Implement water conservation practices to assure sprinkler systems do not
"overspray" vegetated areas and discharge to hard surfaces sucb as
sidewalks, driveways, and parking lots. Adjust sprinkler heads accordingly.
Minimize water use so runoff does not occur or enter storm drainage
systems. Use approaches to reduce water use such as those described in the
Natural Yardcare program.
http://your.kingcounty.gov/solidwaste/natura1yardcare!watering.asp
The King County Noxious Weed Control Program provides best
management practices for the removal of typical noxious weeds such as
blackberry and purple loosestrife. Ca1l206-296-0290 or see
http://www.kingcounty.gov/environmentlanimalsandplantslnoxious-
weedslweed-control-practices.aspx for more information.
ADDITIONAL BMPs
The following BMPs are optional unless the above minimum required
BMPs do not provide adequate source control:
Integrated pest management (IPM), a comprehensive approach to the use of
pesticides is the most effective BMP measure that can be taken for
herbicide, insecticide, and fungicide use.
=> See BMP Info Sheet 6 in Chapter 5 for information on IPM.
Fertilizers should be worked into the soil rather than dumped or broadcast
onto the surface. Determine the proper fertilizer application for the types of
soil and vegetation involved. Soil should be tested for the correct fertilizer
usage.
Use mechanical methods of vegetation removal rather than applying
herbicides.
King County Storm water Pollwon Prevention Manual January 2009
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Landscaping Activities and Vegetation Management (continued)
An effective measure that can be taken to reduce pesticide use, excessive
watering, and removal of dead vegetation involves careful soil mixing and
layering prior to planting. A topsoil mix or composted organic material
should be rototilled into the soil to create a transition layer that encourages
deeper root systems and drought-resistant plants. This practice can improve
the health of planted vegetation, resulting in better disease resistance and
reduced watering requirements.
Use native plants in landscaping. Native plants do not require extensive
fertilizer or pesticide applications.
For more information or assistance in implementing these best management practices. contact the King County
Deparbnent of Natural Resources and Parks Water and Land Resources Division at 206-296-1900.
Reader Note: The above requirements are the minimum required BMPs. If these BMPs fail to prevent discharges to
the storm drainage system, you will be asked to take additional measures to correct the continued pollution
discharges.
January 2009 King County Stormwater Pellutien P",ventlcn Manual
Vehicle and Equipment Parking and Storage
This activity applies to all types of parking lots (commercial, public, and private), retail store
parking lots, fleet vebicle lots and yards (including rent-a-car lots and car dealerships), industrial
areas, equipment sale and rental lots, and parking lot driveways. Stormwater runoff from these
sites can be contaminated with toxic hydrocarbons and other organic compounds, oils and
greases, metals, nutrients, and suspended solids.
January 2009
MINIMUM REQUIRED ROUTINE MAINTENANCE
The following BMPs, or equivalent measures, methods, or practices
are required if you have parking lots and driveways:
Sweep parking lots, storage areas, and driveways as needed to collect
dirt, waste, and debris. Do not hose down the area to the storm drainage
system.
If washing/pressure washing of the parking lot occurs, the wash water
must be collected and discharged to a sanitary sewer or other treatment
system. There are services that will clean parking lots and collect water
for off-site disposal. Never drain washwater to the storm drainage
system.
Y See BMP Info Sheet 2 in Chapter 5 for information on disposal
options.
Gravel and dirt lots may require additional BMPs to prevent sediment
laden water from leaving your site. Vehicles can track dirt out of
parking and storage areas onto public roadways. Basic sediment
controls as outlined in Appendix D ("Erosion and Sediment Control
Standards',) of the King County Surface Water Design Manual must be
installed if other BMPs do not adequately control sediment laden water
from entering off site storm water conveyance systems or surface water.
Wheel wash facilities may need to be considered if track out of mud
becomes a problem. See Activity Sheet A-41, "Wheel Wash and Tire
Bath Operations."
King County Stonnwater Pollution Prevention Manual
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Vehicle and Equipment Parking and storage (conVnued)
ADDITIONAL BMPs
The following BMPs are optionll1. unless the above minimum
required BMPs do not provide adequate source control.
Encourage employees to carpool or use public transit through
incentives.
Encourage customers to use public transit by rewarding valid transit
pass holders with discounts.
A catch basin insert configured for sediment and also oil removal may
remove some of the pollutants in runoff from this activity. Catch basin
inserts may require frequent maintenance to be effective. Carefully
consider this when evaluating your options.
Clean up oil and antifreeze spills with absorbent materials.
Y See BMP Info Sheet lOin Chapter 5 for more information.
For more information or assistance in implementing these best management practices, contact the King COImIy
Department of Natural Resources and Parks Water and Land Resources Division at 206-296-1900.
Reader Note: The above requirements are Ibe minimum required BMPs. If these BMPs fail to prevent discbarges to
the storm drainsge system, you will be asked to take additional measures to correct the continued pollution
discbarges.
King County stOlmwster Pollution PrevenVon Manual January 2009
Sidewalk Maintenance
This activity applies if you have sidewalks. Litter accumulation on sidewalks can contribute
suspended solids to stormwater runoff; runoff from sidewalks crossing driveways may also have
hydrocarbon, oil and grease, and metal contaminants. If herbicides are used on sidewalks, toxic
pesticide compounds, oils, and metals may also be introduced into stormwater. If crack sealants
or surface coatings are applied, toxic hydrocarbons, oils and greases, and metals may be
contributed to stormwater runoff. Sidewalks and driveways are important areas to target for
stormwater pollution control because they typically drain directly to stormwater conveyance
facilities. Note that BMPs for driveways associated with parking lots are described under
Activity Sheet 31, "Vehicle and Equipment Parking and Storage."
January 2009
MINIMUM REQUIREMENTS
The following BMPs, or equivalent measures, methods, or practices
are required if you are engaged in sidewalk maintenance:
Sweep sidewalks as needed to collect loose dirt and debris rather than
pushing it into the street or gutter or hosing it down. Collected materials
must be disposed of as solid waste.
Conduct spot stain removal instead of washing the entire sidewalk. Do
not use soaps and detergents to wash down sidewalks.
If pressure washing of sidewalks is needed, and soaps or other cleaners
are used, the wash water must be collected and disposed of to the
sanitary sewer or taken off site for appropriate disposal. If only water is
used, filtering devices at catch basins must be used to collect all solids
and debris.
King County Stormwater Pollution Prevention Manual
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Sidewalk Maintenance (continued)
•
ADDITIONAL BMPs
The fOllowing BMPs are optional unless the above mjnjmum
required BMPs do not provide adequate source control:
Use deicing salts and sands only when snow or ice is present (not as a
preventive measure) and apply sparingly. Shoveling of snow is always
preferred to dumping excessive amounts of deicing materials in an
effort to avoid shoveling. If deicing salts are used, the residue and
remaining granules must be swept up when the snow and ice have
melted, and reused or disposed of in your garbage.
For more information or assistance in implementing these best management practices, contact the King County
Department of Natural Resources and Parks Water and Land Resources Division at 206-296-1900.
Reader Note: The above requirements are the minimum required BMPs. If these BMPs rail to prevent discharges to
the storm drainage system, you will be asked to take additional measures to correct the continued pollution
discharges.
King County stonnwater Pollution Prevention Manual January 2009
Illicit Connections
An illicit connection is a connection that could convey anything not composed entirely of surface
and stormwater directly to the storm drainage system or a water body. Many buildings
throughout King County could have illicit connections to the storm drainage system. These
typically include, but are not limited to, sanitary sewer pipes, process wastewater discharges,
sump overflows, and internal building drains connected to the storm drainage system. As a result
of illicit connections, wastewater containing a variety of pollutants is discharged directly to
storm drains and drainage ditches, and ultimately to receiving waters rather than to the sanitary
sewer system or a septic system. In many instances these connections are unknown to the
business or property owner, and may not show up on building drawings. Elimination of illicit
storm drainage connections is an important facet of stormwater pollution reduction and must be
addressed as a top priority. King County is currently making a committed effort to determine
where illicit connections are present and to require their removal.
FINDING AN ILLICIT CONNECT/ON
All businesses, residents and public agencies in unincorporated King County must investigate
their plumbing/drainage systems to determine if there are any illicit connections to the storm
drainage system, such as internal floor drains plumbed to the storm drainage system. Ifbuilding
and property drawings are available with plumbing details, they should be reviewed to
understand pipe connections.
If you are unsure whether a particular drain (such as a floor drain) discharges to the storm
drainage system, you should identify where the potential illicit connection drains to by
consulting plans, side sewer cards, and possibly conducting a dye test. Running water from a
hose into the drain and observing where the water discharges is often a very simple and effective
method of identifying illicit connections.
Any pipes or other conveyances connected to storm drainage facilities that drain anything but
stormwater must be permanently plugged or rerouted to a sanitary sewer, holding tank, on-site
process treatment system, or septic system (with approval from the appropriate agencies or
jurisdiction).
If building plans and side sewer cards do not show your plumbing, the most basic methods for
determining a connection is either dye tracing or running water through the system. A nontoxic
dye can be put in water and flushed or drained into the suspect piping. Observations should then
be made in catch basins, manholes, drainage ditches, or other storm drainage conveyances that
January 2009 • King County Stonnwa/er Pollution Prevention Manual
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are present on site (or adjacent to the property) to search for the dye. Enough water must be
poured or flushed through the indoor drain to force the flow to reach the point(s) of observation.
If possible, all other drains in the building should be out of use while the dye test is conducted to
ensure the results can pinpoint the problem drain. This test should be conducted for each suspect
drain on the property. Any observations of dye in the storm drainage system must be noted and
the corresponding indoor drains tagged for followup plugging or rerouting.
If you are uncertain as to the locations of catch basins or manholes that can be used for
observation, or if you can not determine how the storm drainage system is constructed on your
property, contact the King County Water and Land Resources Division (WLRD) at
206-296-1900 for assistance. Notify WLRD at least one day in advance if you are performing a
dye test.
ELIMINA TlNG AN ILLICIT CONNECTION
Drains and pipes that are found to connect to the storm drainage system and have the potential of
discharging pollutants or wastewater must either be permanently plugged or disconnected and
rerouted as soon as possible. Drains that are no longer needed can be plugged with concrete or
another similarly effective material. Whenever process water, stormwater, or other wastewater is
redirected to the sanitary sewer, the local sewer authority and the King County Industrial Waste
Program must be contacted to obtain approval for discharging to the sanitary sewer. The local
sewer authority and King County must also be contacted prior to the installation of any
permanent connection to the sanitary sewer. The name of your local sewer authority is identified
on your water and sewer bill. The local sewer authority and King County Industrial Waste will
regulate the connection both for discharge quantity and quality, but the responsible party will
have to arrange for the necessary plumbing supplies and pipe disconnection/rerouting work.
If a sanitary sewer does not service the property, and one is not available for hookup, alternative
measures are necessary. If the discharge is domestic wastewater from a toilet, sink, appliance, or
showerlbathtub, a septic system can be used to receive the rerouted discharge. The connection of
plumbing fixtures to an on-site sewage disposal system usually requires an on-site sewage
disposal system repair permit. Therefore, before any pipes are rerouted, the Seattle-King County
Department of Public Health must be contacted for further information. If a septic system is not
present on the property then one should be installed. The Seattle-King County Department of
Public Health should be contacted for advice and information on septic system requirements. If
the discharge is industrial process water or other nondomestic wastewater, a holding tank or on-
site treatment system will be needed. If an illicit connection needs to be rerouted to a holding
tank, King County Water and Land Resources Division staff should be contacted for assistance
and information on tank content disposal requirements. As with septic system and sanitary sewer
hookups, the property owner or responsible business operator is responsible for rerouting the
illicit pipe connections.
January 2009 • King County Stann water Pollution Pmvsntion Manual
Disposal Options
Every business, property owner, and public agency in King County must dispose of solid and
liquid wastes and contaminated stormwater properly. There are generally five options for
disposal depending on the types and quantity of materials. These options are: (1) sanitary sewer
system, (2) septic system, (3) recycling, (4) municipal solid waste disposal facilities, and
(5) waste transportation and disposal services. Ordinary stormwater runoff is not considered to
be contaminated to the point of requiring special disposal. Stormwater that is mixed with
concentrated wastes requires special disposal, as discussed below.
DISCHARGE TO SANITARY SEWER SYSTEM
Process wastewater (depending on the pollutants and associated concentrations present) can be
put into the sanitary sewer, subject to approval by the local sewer authority and the King County
Industrial Waste Program. Animal waste can be disposed of in a sanitary sewer, subject to
loading capacity constraints. The King County Industrial Waste Program may require that all
stormwater discharged to a sanitary sewer be metered. Sewer fees may be collected on such
discharges.
The first priority is to discharge process water to a sanitary sewer using an existing plumbing
connection or a new pipe connection. Whenever the diversion of any process water or other
wastewater to the sanitary sewer is needed, the local sewer authority and King County must be
contacted to obtain approval prior to discharging to the sanitary sewer. Pretreatment of
discharges to remove some of the process water pollutants may be required to obtain approval.
The local sewer authority and King County must also be contacted prior to the installation of any
permanent connection to the sanitary sewer. The name of your local sewer authority is identified
on your water and sewer bill. Sumps or other temporary storage devices may be useful for
storing liquid wastes on a temporary basis if you cannot discharge to a sanitary sewer system.
Consideration should be given to using a holding tank for process water if the volume of process
water generated by the activity is not excessive. See BMP Info Sheet 4 for more information on
holding tanks. The contents of the holding tank must be pumped out or drained before the tank is
full. Several commercial services are available for pumping out sumps and holding tanks. These
can be found in your telephone directory's yellow pages under the headings "Sewer Contractors
and Cleaners" and "Tank Cleaning," or on the King County Stormwater Services website at
http://www.kingcounty.gov/environmentlwaterandland/stormwater/problem-investigation-
line/drainage _ maint_ vendors.aspx. Septic system pumpout and hauling contractors must not be
used for disposing wastes other than domestic sewage. They are not allowed to haul industrial
wastes .
January 2009 • King County Slormwaler Pollution Pl&venllon Manual
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BMP Info Sheet #2, Disposal Options (continued)
DISCHARGE TO SEPTIC SYSTEM
If your site is not serviced by a sanitary sewer system, you probably have a septic system. Only
liquid waste that is comparable to residential sewage in strength and constituency may be
disposed of in septic systems. Hazardous chemicals cannot be disposed of in septic systems.
Further, the septic system must be designed to accommodate the volume of suitable wastewater
generated. Any changes in waste volume and constituency from those present when the system
was permitted must be approved by the Seattle-King County Department of Public Health.
Stormwater, whether contaminated or not, may not be disposed of in septic systems. Animal
waste may not be disposed of in a septic system designed for single family, multifamily or
commercial properties.
RECYCLING
Recycling facilities are a recommended option for many commercial items, including used oils,
used batteries, a variety of used auto parts, metal scrap materials, solvents, paints, and other solid
wastes. There are a number of private businesses that accept materials for recycling. In addition
there is an Industrial Material Exchange clearinghouse which facilitates the transfer of unwanted
materials from the generator to another business that can use them. The Industrial Material
Exchange or IMEX website is http://www.govlink.orgihazwasteibusiness/imex.
Process wastewater such as wash water can be recycled on-site as an alternative to discharge to
the sanitary sewer. There are numerous products on the market that are designed to recycle wash
water. Contact the King County Water and Land Resources Division at 206-296-1900 for more
information.
MUNICIPAL SOLID WASTE DISPOSAL FACILITIES
Muuicipal solid waste disposal facilities are designed to handle solid wastes. Hazardous and
dangerous wastes and many liquid wastes must be properly disposed of at an appropriate facility.
Contact your local solid waste disposal facility or see http://your.kingcounty.gov/solidwaste/
garbage-recycling/index. asp for information on which materials are accepted at these facilities.
Call the Business Waste Line at 206-296-3976 or see http://www.govIink.orgihazwastelbusiness
for information on the proper disposal of oil, antifreeze, and other hazardous wastes.
WASTE TRANSPORTATION AND DISPOSAL SERVICES
There are numerous services that can help you identify, quantify, transport, and dispose of any
waste that you may generate. Many people have their wastes picked up by a disposal contractor.
Costs of disposal vary considerably depending on the types of materials, quantities, methods of
collection and transport, and whether the wastes are mixed. The rate the contractor charges will
generally reflect the costs of testing and/or treating waste materials (if necessary) and the
subsequent disposal. It is important to keep different types of wastes separated, so that the
disposal contractor(s) can take them to the appropriate place(s) without causing inadvertent
contamination problems elsewhere, and so that you are not paying too much for disposal of
January 2009 • King County Stonnwater Pollution Prevention Manual
BMP Info Sheet #2, Disposal Options (continued)
materials that are not contaminated (e.g. regular garbage). If you are properly implementing your
BMPs and collect contaminated waste materials for proper disposal, your efforts are
compromised if a disposal contractor subsequently disposes the contaminated materials as
regular garbage. Therefore, it is essential to be familiar with disposal alternatives and the
different types of contractors for each disposal option.
The Seattle-King County Department of Public Health's Waste Characterization Program serves
hazardous waste generators in Seattle and King County that have questionable wastes.
Information supplied by the generator on questionable wastes such as sludges, sandblast waste,
treated wood, and contaminated soils is reviewed by the Health Department. Permits are issued
for those wastes that will be allowed in the garbage. The dangerous waste regulations as well as
other criteria are used in the decision process.
The disposal of wastes is the responsibility of the generator. Before agreeing to let a company
handle your waste, it is recommended that you ask for (and check) the company's references. All
waste collected by the company should be delivered to an authorized site. Make sure you keep
copies of all your transactions. Transfer of waste to a vender does not release you from legal
obligation for disposal to a licensed disposal facility.
January 2009 • Klng County Stormwater Pollution Pl'9vention Manual
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Maintenance of Drainage Systems
Many commercial, industrial, residential and public agency properties have storm drainage flow
control and water quality systems to capture and treat stormwater flows. Most of these systems
have catch basins as key components. Catch basins are typically located along curbs, at low spots
in parking lots, and where stormwater conveyance pipes combine flows. Storm drains collect
runoff that directs flows into basins and pipes that are located underneath parking lots and storm
drain grates. Most catch basins have a few feet of storage in the bottom or sump. This storage
area is intended to trap sediment, dehris, and other particulates that settle out of stormwater, to
prevent clogging of downstream pipes and to keep solids from being flushed into receiving
waters.
Anyone who has ever looked into a catch basin can attest to its ability to capture dirt, leaves,
twigs, litter, and a variety of other materials that make for a mucky buildup in the bottom.
However, if the sump (the bottom of the catch basin) is full of solid material, everything in the
incoming runoff passes straight through to an outflow pipe. The bottom ( or sump) in catch basins
must be cleaned out periodically so they can continue to trap solids from stormwater runoff.
Routine maintenance practices at all sites with storm drains and catch basins must include
cleaning/removal of sediment or solids from these important drainage system features. If catch
basins are not cleaned, they can actually contribute to receiving water pollution problems as
trapped solids, and stagnant, polluted water in sumps can be flushed out in large quantities with
turbulent storm flow conditions.
Check your catch basins annually for needed maintenance timed to occur before the rainy
season. For organizations with large numbers of catch basins (greater than 50 per site),
inspections may be conducted on a "circuit basis" whereby sampling of representative catch
basins, including the lowest one in the circuit, within each circuit is inspected to identify clean-
out needs for the circuit. The annual catch basin inspection schedule may be changed as
appropriate to meet the maintenance standards based on maintenance records of double the
length of time of the proposed inspection frequency. Catch basins must be cleaned out when the
solids, trash, and debris in the sump reaches one-half of the depth between the bottom of the
sump and the bottom (invert) of the lowest inflow or outflow pipe connected to the catch basin or
at least 6 inches below this invert. The rate at which a sump fills with solid material is quite
variable, and depends on the characteristics of the drainage basin feeding into it. If activities that
generate a lot of sediment are taking place in the drainage area that contributes stormwater flows
to a catch basin, such as exposing soils due to construction or landscaping, stockpiling erodible
materials, or if your site is not paved and has heavy traffic use on dirt or gravel surfaces, the
sump will fill up relatively quickly. Therefore, sites with activities generating a lot of sediments
and other debris will have to inspect and clean out their catch basins more often.
January 2009 • King County stonnwater Pollution Prevention Manual
BMP info Sheet #7, Maintenance of Drainage Systems (conUnued)
Other components of drainage systems include ponds, tanks, and bioswales. These components
must also be maintained to ensure your drainage systems functions as designed. Vegetation in
ponds and bioswales must be mowed or thinned, and sediment accumulations must be removed.
Maintenance of ponds, tanks, and bioswales is generally beyond the ability of the typical
property owner. Drainage system maintenance contractors are available to complete this work.
If you clean out/maintain the catch basins yourself, you may dispose of up to one cubic yard of
solid material as solid waste in your regular garbage. If you exceed this threshold you are
encouraged to contact a company offering catch basin cleaning services. You can locate a
cleaning service by calling the King County Water and Land Resources Division at
206-296-1900 for a list of firms performing drainage system maintenance services or in your
telephone directory's yellow pages under headings like "Sewer Cleaning Equipment and
Supplies," "Sewer Contractors," and "Tank Cleaning." All of the solids and stagnant water
collected from catch basin sumps must be disposed of properly. None of the sump contents can
be flushed into the catch basin outflow pipe. Depending on the nature of the pollutants in the
sump, and the associated types of activities taking place on the site, the sump contents may need
to be handled as contaminated waste. Contractors who perform catch basin clean-out services are
required to follow appropriate disposal requirements.
Frequent sweeping of paved parking and storage areas, covering pollutant generating activity
areas, and containing runoff from activity areas will help reduce catch basin and drainage system
cleaning frequency, and may save time and money spent on required maintenance. All
businesses and public agencies should set up maintenance schedules for all of their BMPs so that
coordinated BMP efforts result in reduced catch basin and drainage system maintenance and
cleaning.
January 2009 • King County SWl7nwater Pollution Prevention Manual
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