Brackett's Corner - Drainage Report.pdf
PRELIMINARY DRAINAGEREPORT
FOR
"± ¢ª¤³³Ȍ² #®±¤±
Redevelopment
at
8000 212 ST SW
Edmonds,Washington98026
September2015
Prepared By:
Kirk Myklestad, E.I.T.
John Yuen, P.E.
Lovell-Sauerland & Associates, Inc.
th
19217 36Ave. W., Suite 106
Lynnwood, Washington 98036
LSA FILE No: 5537
Figure-A
Determining Applicability of Stormwater Management Code ECDC Chapter 18.30
If any of the descriptions in the Blue Boxes apply to your project or project site, the
Stormwater Management Code applies.
Does your Project Site require the issuance of a City
Yes
permit under any of the following:
ECDC Title 18 - Engineering Division
ECDC Title 19 - Building Division
2
A Stormwater Permit
No
Yes
Are you submitting a Subdivision application per
ECDC Chapter 20.75?
No
Does your Project site involve any of the following: Stormwater
Management
500 square feet or more of land-
Yes
requirements of ECDC
disturbing activity, new impervious
Chapter 18.30 are
surface, or replaced impervious
applicable to your
surface?
Project or Site.
A utility or other construction project
consisting of 500 lineal feet or more
of trench excavation?
Is located in, adjacent to, or drains
into (currently or as a result of the
project) a Critical Area or a Critical
Area Buffer?
No
Stormwater Management
requirements of ECDC Chapter
18.30 are not applicable to your
1
Project or Site
Note: The definitions of the terms in italics are found in ECDC Chapter 18.30.010 and the Stormwater Code Supplement.
______________________________
1
This chart provides an initial screening for determining the applicability of ECDC Chapter 18.30. The results from using this chart
do not substitute for a determination of applicability by the Public Works Director or Designee per ECDC Chapter 18.30.030 and
the relevant portions of the Supplement.
2
If ECDC Chapter 18.30 is applicable to the proposed project and it does not require any other City-issued permit, a Stormwater
Permit and associated fees will be required.
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Figure-B
Project Classification
If you have determined that the Stormwater Management Code
applies to your project (Figure-A), follow the Blue boxes in the chart
below to determine the Classification of your project.
Yes
Does the project involve 1-
acre or more of land-
Large Site Project:
1
disturbing activity ?
See Stormwater Supplement
No
Chapter 4 for specific
Yes
Is the project part of a larger
requirements
.
common plan of development or
sale where the total disturbed area
for the entire plan will total 1-acre
Does the project create or add 5,000 square feet or
or more of land-disturbing activity?
more of new impervious surface, regulated
replaced impervious surface or new plus
No
regulated replaced impervious surface?
OR
Does the Project involve one or more of the
Convert ¾ acre or more of native vegetation to
following:
lawn or landscaped area
Yes
new
2,000 square feet (sf) or more of
OR
impervious surfaceregulated replaced
,
Through a combination of creating effective
impervious surface
or new plus regulated
impervious surface and converted pervious
replaced impervious surface?
surfaces, causes an increase of 0.1 cubic feet per
OR
second in the 100-year flow frequency from a
land-disturbing activity
7,000 sf or more of ?
threshold discharge area as estimated using an
OR
approved model?
50 cubic yards or more of either grading, fill, or
excavation as defined in Chapter 18.40.000
ECDC?
No
Yes
No
Minor Site Project: Category 1 Small Site Project: Category 2 Small Site Project:
See Stormwater Supplement See Stormwater Supplement See Stormwater Supplement
Chapter 6 for specific Chapter 5 or specific Chapter 5 for specific
requirements requirements
requirements
Notes:
Terms in bold italics are described in the Glossary on pages 10-11. The definitions of the all terms in italics are found in ECDC
Chapter 18.30.010 and the Stormwater Code Supplement
The Classification flowchart assumes the project in question meets the applicability requirements of ECDC18.30.030.
________________________________
1
Land-disturbing Activity: Any activity that results in the movement of earth, or a change in the existing soil cover (both
vegetative and non-vegetative) or the existing soil topography. Land disturbing activities include, but are not limited to grading,
filling, excavation, and compaction associated with stabilization of structures and/or road construction.
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The projects Site Classification will dictate the specific stormwater management
requirements applicable to your site. Completing this worksheet will help determine the amount of
Small Site
regulated impervious surface and whether your project falls into the classification of a
Minor Site
(Category 1 or Category 2), or a . Please reference the Glossary (pp. 10-11), Figures D and
E, (pp. 8-9), and Examples (pp. 11-12), to assist with completion of this worksheet.
1
1)Is Permeable Pavement Proposed For Use on this Site?
Yes No
Refer to Stormwater Supplement Chapter 5.1
YES
If , the subject area is to be considered impervious for initial site classification purposes. Include total
permeable pavement area in the calculation of Non-Regulated, Replaced and/or New impervious surface
areas in the table below.
2)Determine the Amount and Type of Existing & Proposed Impervious Surface for the Site
Refer to Stormwater Supplement Chapter 2 and Fig. C
Line 1Non-Regulated Impervious Surface Area.
: Identify the
Line 2Replaced Impervious Surface Area
: Identify the , dividing the total between Exempt and Regulated; either or both
Replaced Impervious
may be zero. Note: For project classification purposes, may only be considered exempt
under certain conditions. Refer to the Glossary and Figure D.
Line 3New Impervious Surface Area
: Identify the for your project. All impervious areas created post-July 7, 1977 or
after the date of annexation into the City are regulated & should be included in this total unless they can be
categorized separately as a Replaced-Regulated area.
Line 4plus
: Enter the sum of the total Replaced-Regulated the total New impervious areas.
Line 5
: Identify the total area currently mitigated by an existing city-approved stormwater management system.
Line 6
: Enter the sum of the value in Line 4 less the value in Line 5 to identify the total Regulated area in which
stormwater controls have not yet been applied.
Line 7
: Identify the total area proposed to be mitigated through the use of Low Impact Development Techniques.
Line 8
: Identify the total area proposed to be mitigated through conventional Stormwater Management Techniques.
** Provide a copy of the following table on the drainage plan sheet for the proposed project **
Line Type Area (square feet)
0
1. Non-Regulated
Exempt Regulated
0
0
2. Replaced
32,582
3. New (Post 1977) +
Total Regulated Impervious Area
32,582
=
4.
Mitigation required if in excess of 2000sf
0
5. Total Area Mitigated by Existing Stormwater Management System(s) -
32,582
6. Regulated Area Not Yet Mitigated =
32,582
7. Area Proposed to be Mitigated by Low Impact Development Techniques =
0
8. Area Proposed to be Mitigated through Conventional SWM Techniques =
1
(e.g. porous asphalt, porous concrete, paver blocks, concrete open celled paving grids, or plastic lattices filled with turf or stone)
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3)Determine the Total Area of Land Disturbing Activity
43,649
________ sf
Refer to Stormwater Supplement Chapter 8
0
net
4)Determine the Quantity of Grading, Fill and/or Excavation ________cy
750cyCUT&750cyFILL
5)Will the project convert ¾ Acre or More of Native Vegetation to Lawn or
Yes No
Landscaped Area?
6)Identify the Watershed the Existing Site Runoff Discharges to
Refer to Stormwater Supplement Chapter 2.3
Based on Site Location and Watershed Map Figure-C. Check all that apply.
A. Direct Discharge B. Creek or Lake Basin
Edmonds Way Basin
Puget Sound Basin
Puget Sound Piped Basin
DETERMINE PROJECT CLASSIFICATION USING THE INFORMATION ABOVE
PROJECT CLASSIFICATION CHART
AND THE (Figure B, pg 4)
Small Site - Category 1
Small Site - Category 2
Stormwater Supplement
Stormwater Supplement Stormwater Supplement
Chapter 5
Chapter 5
Chapter
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APRIL 2010 EDMONDS STORMWATER CODE SUPPLEMENT
Figure 4-1: Flow Chart for Determining Minimum Requirements for New Development on Large Site Projects
27
4.0 LARGE SITE REQUIREMENTS
APRIL 2010 EDMONDS STORMWATER CODE SUPPLEMENT
Figure 4-2: Flow Chart for Determining Minimum Requirements for Redevelopment on Large Site Projects
28
4.0 LARGE SITE REQUIREMENTS
Brackett’s Corner Redevelopment
Introduction:
This summary report provides engineering site design information for the proposed building permit application
for the redevelopment of 8000 212 ST SW. The property is located in the northwest1/4 of thenortheast1/4 of
Section 30, T27N, R4E, W.M.
Applicant/Owner:Site Address:
th
Pride Ventures LLC8000 212ST SW
P.O. Box 429Edmonds, WA 98026
Edmonds, WA 98020
Contact: Jacob LyonTax Parcel Numbers:
Phone: (425) 422-005300373600300103
00373600300104
00373600300105
TABLE OF CONTENTS
SECTION TABLE OF CONTENTS
A.Project Summary
B.Vicinity/Parcel Map,Aerial Photo,WatershedBasin Map& Soils Classification Map
C.Storm Drainage Summary and Calculations
D.Grading and Erosion Control Summary
E.Operations & Maintenance Guidelines
APPENDICS
A.WWHM3 Report
B.Custom Soil Resource Report
C.Geotechnical Report
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Preliminary DrainageReport September, 2015
LSA No. 5537
Section A
Project Summary
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SITE CONDITIONS:
The projectsite consists of approximately43,649square feetof land and is currently occupiedby three
structuresand associated asphalt pavingcovering the majority of the lot.Smallareas of vegetation consisting
primarily of grass and small shrubberyare interspersed throughout the site. A group of 19 trees are spread
horizontallyalongthe lowerthird of the project site.The site is bordered by single family residencesto the
thth
Avenue W. to the east, and 212StreetS.W. to the north. Access to the site is directly
west and south,80
thth
Avenue W. and 212Street S.W.The sitegenerallyslopes towards the south with an
from both 80
approximateslope of3to 5%. Runoff from the site currently sheet flows in a similar direction, with no signs
of a defined channel.
Existing Features Summary:
a.Site Area...........................................................................................43,649square feet
b.Offsite tributary area:Negligible
c. Soil Hydrologic Type: Alderwood–Urban Land Complex, 2to 8percent slopes-hydrologic group B
(from NRCS soils survey-See Appendix B)
Theproposed project is to redevelop the site by removing all existing paving and structuresin order to
th
Avenue W. The total
construct14 new single family residences surrounding a new roadwayconnectingto 80
new and replaced impervious totalisestimated at 32,582 sf. Accessto the houseswill be provided by a new
th
Avenue W.at two points along the project’s
roadway, looping throughthe property and connecting to 80
eastern boundary.Landscaping and grass lawn will surround significant portions of the new housesand will
stabilize the site upon building construction.See attached civil plan setfor detailedlocations.
Three existing water meters and water lines were found on the project site, one on the north boundary and two
on the east. The two eastern connections will be reused for the newdevelopment. Two sanitary laterals were
found connecting to existing buildings on the north half of the lot. Both lines will be reusedfor the proposed
construction. See attached sewer and utility plan (C4) for exact locations.
Additionally, a new sewer main will be extended along the projects eastern boundary. The line will belocated
th
Avenue W and will gravity flow to the existing line in
within the planting stripalong the western side of 80
th
Street S.W.
212
Summary of Project Minimum Requirements:
5.1 MinimumRequirement #1 –Preparation of Stormwater Site Plan. The proposed site development
consists of disturbing approximately 1.00acre of land and creatingapproximately32,582square feetof
impervious surfacesby adding 14new single family residencesand associated site paving.The project is
classified as a Large Site Projectper the City’s classification systemasit involves at least one acre of land
disturbing activity.A site development plan hasbeen prepared and is included with the submitted plan set, see
sheet C3.
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
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5.2 MinimumRequirement #2 –Construction Stormwater Pollution Prevention. A summary of the site’s
proposed grading and erosion control measures,along with agrading estimate,are included in section D.
Grading and Erosion Control Summary.Thegrading quantities are estimated to be 750CY of cut and 750
CY of fill. The total site disturbance area of the project is approximatelyone acre, thus a formal Notice of
Intentapplication for NPDES coverage will be made to the Department of Ecologyby the applicant.
5.3 Minimum Requirement #3 –Source Control of Pollution. Per the City of Edmonds Stormwater code
Supplement 18.30, specific source controls are not required for single family residential sites. Runoff from
pollution generating impervious surfaces is being addressed per MR#6, see section 5.6.
5.4 Minimum Requirement #4 –Preservation of Natural Drainage Systems and Outfalls. The site currently
sheet flows south towards adjacent properties.The project proposes to connect newonsite stormwater
infiltration facilities to the existing storm drainage systemlocated on the northeast corner of the property,
th
within 80Avenue W.Infiltration facilities are designed to fully mitigate the projects runoff onsite and
connectto the public system for overflow purposesonly.The project site is within both the Good Hope Pond
and the Halls Creek WatershedBasins. According to the City of Edmond’s maps,the southeastern thirdof the
project site is located within the Halls Creek Basin while theremaining northwestern segment is within the
Good Hope Pond Basin.
5.5Minimum Requirement #5 –Onsite Stormwater Management. Through a collection of pipes, catch
basinsand downspout connections,the site’s impervious surfaces will be collected and routed to aseries of
th
infiltration trenches located onsite, before overflowing to the existing public storm drainage system in 80
Avenue W.In order to implement these LID infiltration based control measures a geotechnicalreport was
obtained, see Appendix C. See additional discussion for the on-site stormwater management in MR#7, section
5.7.
5.6MinimumRequirement #6 –Runoff Treatment. All pollution generating impervious surfaces proposed
by the project will be collected atcatch basins equipped with separators before being routed to infiltration
trenches located along the site’s northern and eastern boundaries. Pollution generating impervious surfacesare
limited to thenew roadway and attached parking stalls, totaling approximately 10,024 sf.
5.7 Minimum Requirement #7 –Flow Control. All runoff will be fully infiltrated onsite. A connection to the
public storm drain system is provided for emergency overflow only.See section C for storm drainage
calculations.
5.8 Minimum Requirement #8 –Wetland Protection. No wetlands are known to exist on or adjacent to the
project site.
5.9 Minimum Requirement #9 –Operation and Maintenance.An operation and maintenance summary is
provided in section E.
5.10 Minimum Requirement #10 –Offsite Analysis and Mitigation.A quantitative offsite analysis has not
been conducted for this project as the stormwaterimpact on adjacent properties should not be increased as a
result of the proposed construction.As discussed above, runoff associated with the property previously sheet
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
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flowed towards theadjacentsouthern properties. Areas converted to impervious surfaceswill now be collected
th
bythe proposed drainage system and infiltrated onsite. Thecapacityof the system under 80Avenue W. is
believed to be adequate with no unacceptable downstream issues.
5.11 Minimum Requirement #11 –Financial Liability. Cost estimates and bonds will be provided by the
applicant during final construction permit approval.
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Preliminary DrainageReport September, 2015
LSA No. 5537
Section B
Vicinity/ParcelMap,Aerial Photo,Watershed BasinMap & Soil Classification Map
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
Preliminary DrainageReport September, 2015
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Vicinity / Property Parcel Map
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Aerial Photo
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Watershed Basin Map
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SoilsClassification Map
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Section C
Storm Drainage Summary and Calculations
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LSA No. 5537
STORM DRAINAGE SUMMARY AND CALCULATIONS:
Site runoff will be collected in a systemof pipes, catch basins and downspout connectionsbefore routingto a
seriesof onsite infiltration trenches. The trenches are sized in order to fully mitigate the sites impervious
th
Avenue W.
surfaces before overflowing to the existing public storm drainage system in 80
In order to implement these LID infiltration facilities,a Geotechnical report was obtained, see Appendix C.
The report recommends a design infiltration rate of 2.0 in/hr.
Infiltration trenches were sized using the Western Washington Hydrology Model (WWHM3). This software
program is released by the Department of Ecology and is used to size stormwater control facilities in western
Washington. WWHM3 uses the EPA HSPF software program to perform continuous storm modeling of
rainfall-runoff and routing computations. WWHM3 models the rainfall-runoff for pre and post development,
and performs sizing for detention and infiltration facilities in order to meet Ecology’s flow control minimum
requirement #7 (stream protection duration).
The pre-developed conditions of the entire 1.00 acres of on-site development are assumed to be forested.
The post-developed area includes 0.252 acres of lawn area (25.2%) and 0.748 acres of impervious (74.8%).
The following table details the impervious surfaces associated with the project:
Impervious Areas
On-SiteOff-Site
Buildings18,241 SFRoadway 540 SF
TOTAL540 SF
Roadway7,610 SF
Sidewalk3,777 SF
Parking2,414 SF
TOTAL32,042SF32,582 SF
PROJECT TOTAL
Post-Construction Soil Quality and Depth practicesper the City of Edmondswill be used for all areas subject
to clearing and grading that have not been covered by impervious surfaces.
The Puget East 36 precipitation time series and the non parametric Gringorten plotting position formula were
usedfor modeling in accordance with the City of Edmonds Stormwater Code Supplement 18.30.
Shown on the following pagesare theWWHM pre-developed and post-development drainage basins,as well
asthedesigned trench and associated flow frequencytable.See Appendix A for the full WWHM3 output
report.
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
Preliminary DrainageReport September, 2015
LSA No. 5537
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
Preliminary DrainageReport September, 2015
LSA No. 5537
The model shows that a trenchlength of 324ftisadequateto fully infiltrate the site’s stormwater runoff.An
emergency overflow to the public storm drain system is provided at the northeastcorner of the site.
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
Preliminary DrainageReport September, 2015
LSA No. 5537
Section D
Grading and Erosion Control Summary
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
Preliminary DrainageReport September, 2015
LSA No. 5537
GRADING AND EROSION CONTROL SUMMARY:
The project will require moderate grading in order to construct the proposedsingle family residencesand
associatedsite paving. Standard erosion control measures are proposedtobe used during construction. The
primary erosion and sediment control “best management practice” (BMP) during construction will be
proper soil stabilization methods. Exposed soils shall be stabilized by application of effective BMP’s that
protect the soil from the erosive forces of raindrops, flowing water, and wind.
Appropriate BMPs include, but not limited to, temporary and permanent seeding, sodding, mulching, plastic
covering, erosion control fabrics, matting, soil application of polyacrylamide (PAM) , the early application of
gravel base on areas to be paved, and dust control. The contractor shall select a soil stabilization method best
suited for the particular situation. Stock piles must be stabilized and protected with sediment trapping
measures. In addition, site containment of exposed soils shall be sustained by using silt fence barriers along
the down-slope boundaries of the site’s disturbance areas.
Soil Type:6-Alderwood-Urban Land Complex,2-8% slopes
Hydrologic Group = “B”
The grading amounts associated with the project have been approximated as shown below.The quantities
listed are for the permitting process only and should not be considered precise amounts for bidding purposes.
The estimated grading quantities are:
Approximate Cut:750CY
Approximate Fill:750CY
Included in theattached civil plan set are site development plans, proposedgradesand drainage improvement
notes and details. With proper installation, maintenance and inspections of the proposed construction the
project should have minimal impact onthe surrounding environment.
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LSA No. 5537
Section E
Operation and Maintenance Guidelines
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OPERATION AND MAINTENANCE GUIDELINES:
Operation and Maintenance Requirements:
These guidelines are intended to provide operation and
th
maintenance instructions for the new single family residencesat 8000 212Street S.W. and theirstorm
drainage control facilities. The ownersareresponsible for maintenance of storm drainage facilities within
the property. The ownersarenot responsible for maintenance within the public right-of-way.
This manual is not comprehensive. Although it explains the intended operation of the various components of
the drainage system, and suggests a routine of inspection and maintenance, it cannot anticipate every problem.
Once a historical record of maintenance is established, it may be prudent to alter the routine. It is
recommended that maintenance records be kept, and that the records be reviewed periodically.
Concept of Operation:
The drainage design is shown and described in the final site development engineering
plans and report. The approved site development plans and report should be retained by the owner and used as
a reference to identify drainage facilities outlined in this manual.
Conveyance Systems.The design objective in pipe sizing was to convey the 100-year storm without the water
surface exceeding the overflow elevation of the proposed facilities. Frequent overtopping of the pipe system in
aparticular area might indicate a downstream blockage. Overtopping of the drain systems at the yard drains or
cleanouts is an indication that maintenance is required.
Recommended Inspections of Facilities.The following are inspection guidelines for the drainage system. The
inspections should occur prior to the winter rain season, leaving sufficient time to correct any detected
maintenance problems, and at the end of the season to determine the effect of the season’s runoff. Once a
historical basis is developed the frequency of inspection may be modified as necessary.
For additional and updated maintenance information visit the Washington State Department of Ecology’s
http://www.ecy.wa.gov/programs/wq/wqhome.html
web-site at:
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Preliminary DrainageReport September, 2015
LSA No. 5537
4.6Maintenance Standards for Drainage Facilities
The facility-specific maintenance standards contained in this section are
intended to be conditions for determining if maintenance actions are
required as identified through inspection. They are not intended to be
measures of the facility's required condition at all times between
inspections. In other words, exceedence of these conditions at any time
between inspections and/or maintenance does not automatically constitute
a violation of these standards. However, based upon inspection
observations, the inspection and maintenance schedules shall be adjusted
to minimize the length of time that a facility is in a condition that requires
a maintenance action.
Table 4.5 – Maintenance Standards
No. 1 – Detention Ponds
MaintenanceDefectConditionsWhen Maintenance IsResults Expected When
ComponentNeededMaintenance Is Performed
GeneralTrash & Debris Any trash and debriswhich exceed 5 Trash and debris cleared from site.
cubic feet per 1,000 square feet (this
is about equal to the amount of trash
itwould take to fill up one standard
size garbage can). In general, there
should be no visual evidenceof
dumping.
If less than threshold all trash and
debriswillbe removed as part of next
scheduled maintenance.
PoisonousAnypoisonous or nuisanceNo danger of poisonous vegetation
Vegetation andvegetationwhich may constitute a where maintenance personnel or the
noxious weedshazard to maintenance personnel or public might normally be. (Coordinate
the public.with local health department)
Anyevidence of noxiousweeds as Complete eradication of noxiousweeds
defined by State or local regulations.may not be possible. Compliancewith
State or local eradication policies
(Apply requirements of adopted IPM
required
policies for the use of herbicides).
No
ContaminantsAnyevidence of oil, gasoline,
contaminants
and Pollutioncontaminants or other pollutants
or pollutants
(Coordinate removal/cleanupwith
present.
localwater quality response agency).
Rodent HolesAnyevidence of rodent holes if Rodents destroyed and dam or berm
facilityis acting as a dam or berm, or repaired. (Coordinatewith local health
any evidence ofwater piping throughdepartment; coordinatewith Ecology
dam or berm via rodent holes.Dam Safety Office if pond exceeds 10
acre-feet.)
4-30Volume V – Runoff Treatment BMPs February 2005
No. 2 – Infiltration
MaintenanceDefectConditionsWhen Maintenance IsResults Expected When
ComponentNeededMaintenance Is
Performed
GeneralTrash & Debris See "DetentionPonds" (No. 1). See "Detention Ponds"
(No. 1).
Poisonous/NoxiousSee "Detention Ponds" (No.1).See "Detention Ponds"
Vegetation(No. 1).
ContaminantsandSee "Detention Ponds" (No.1).See "Detention Ponds"
Pollution(No. 1).
Rodent HolesSee "Detention Ponds" (No. 1). See "Detention Ponds"
(No. 1)
Storage AreaSedimentWater ponding in infiltration pond after Sediment is removed
rainfall ceases and appropriate time and/or facilityis cleaned
allowed for infiltration. so that infiltration system
works according to
(A percolation test pit or test of facility
design.
indicates facility is onlyworking at 90% of
its designed capabilities. If two inches or
more sediment is present, remove).
Filter Bags (if Filled withSediment and debris fill bag more than 1/2Filter bag is replaced or
applicable)Sediment andfull.system is redesigned.
Debris
Rock FiltersSediment andBy visual inspection, little or no water flowsGravel in rock filter is
Debristhrough filter during heavy rain storms. replaced.
Side Slopes of ErosionSee "Detention Ponds" (No. 1). See "Detention Ponds"
Pond(No. 1).
EmergencyTree GrowthSee "Detention Ponds" (No. 1). See "Detention Ponds"
Overflow Spillway(No. 1).
and Berms over 4
feet in height.
PipingSee "Detention Ponds" (No. 1). See "Detention Ponds"
(No. 1).
EmergencyRock MissingSee "Detention Ponds" (No. 1). See "Detention Ponds"
Overflow Spillway(No. 1).
ErosionSee "Detention Ponds" (No. 1). See "Detention Ponds"
(No. 1).
Pre-settlingFacility or sump6" or designedsediment trap depth of Sediment is removed.
Ponds and Vaultsfilled withSedimentsediment.
and/or debris
February 2005Volume V – Runoff Treatment BMPs 4-33
No. 5 – Catch Basins
MaintenanceDefectConditionsWhen Maintenance is NeededResults Expected When
ComponentMaintenance is
performed
GeneralTrash&Trash or debriswhich is located immediatelyNo Trash or debris located
Debrisin front of the catch basin opening or is immediately in front of
blocking inletting capacityof the basin bycatch basin or on grate
more than 10%.opening.
Trash or debris (in the basin) that exceeds 60No trash or debris in the
percent of the sump depth as measured from catch basin.
the bottom of basin to invert of the lowest
pipe into or out of the basin, but in no case
less than a minimum of six inches clearance
from the debris surface to the invert of the
lowest pipe.
Trash or debris in any inlet or outlet pipeInlet and outlet pipes free
blocking more than 1/3 of its height.of trash or debris.
Dead animalsor vegetation that couldNo dead animals or
generate odors that could cause complaintsvegetation presentwithin
or dangerous gases (e.g., methane).the catch basin.
SedimentSediment (in the basin) that exceeds 60No sediment in the catch
percent of the sump depth as measured from basin
the bottom of basin to invert of the lowest
pipe into or out of the basin, but in no case
less than a minimum of 6 inches clearance
from the sediment surface to the invert of the
lowest pipe.
StructureTop slab has holes larger than 2 squareTop slab is free of holes
Damage to inches or crackswider than 1/4 inch and cracks.
Frame and/or
(Intent is to make sure no material is running
Top Slab
into basin).
Frame not sitting flush on top slab, i.e., Frame is sitting flush on
separationof more than 3/4 inch of the frame the riser rings or top slab
from the top slab. Frame not securelyand firmly attached.
attached
Fracturesor Maintenance person judgesthat structure is Basin replaced or repaired
Cracks in unsound.to design standards.
Basin Walls/
Bottom
Grout fillet has separated or crackedwiderPipe is regrouted and
than 1/2 inch and longer than 1 foot at the secure at basinwall.
joint of any inlet/outlet pipe or any evidence of
soil particles entering catch basin through
cracks.
Settlement/If failure of basin has createda safety,Basin replaced or repaired
Misalignmentfunction, or design problem.to design standards.
VegetationVegetationgrowingacross and blocking moreNo vegetation blocking
than 10% of the basin opening.opening to basin.
Vegetation growing in inlet/outlet pipe jointsNo vegetation or root
that is more than six inches tall and less thangrowth present.
six inches apart.
4-36Volume V – Runoff Treatment BMPs February 2005
No. 5 – Catch Basins
MaintenanceDefectConditionsWhen Maintenance is NeededResults Expected When
ComponentMaintenance is
performed
ContaminationSee "Detention Ponds" (No. 1). No pollution present.
and Pollution
Catch BasinCover Not in Cover is missing or only partiallyin place.Catch basin cover is
CoverPlaceAnyopen catch basin requires maintenance.closed
LockingMechanism cannot be opened byoneMechanism openswith
Mechanismmaintenance personwith proper tools. Boltsproper tools.
Not Working into frame have less than 1/2 inch of thread.
CoverDifficultOne maintenance person cannot remove lidCover can be removed by
to Remove after applying normal lifting pressure.one maintenance person.
(Intent is keep cover from sealingoff access
to maintenance.)
LadderLadderRungsLadder is unsafe due to missing rungs, not Ladder meets design
Unsafesecurely attached to basin wall,standards and allows
misalignment, rust, cracks, or sharp edges. maintenance person safe
access.
Metal GratesGrate openingGratewith openingwider than 7/8 inch. Grate opening meets
(If Applicable)Unsafedesign standards.
TrashandTrash and debris that is blocking more thanGrate free of trash and
Debris20% of grate surface inletting capacity.debris.
DamagedorGrate missing or broken member(s) of the Grate is in place and
Missing.grate.meets design standards.
No. 6 – Debris Barriers(e.g., Trash Racks)
MaintenanceDefectCondition When Maintenance isResults Expected When
ComponentsNeededMaintenance is Performed
GeneralTrashandTrash or debris that is plugging more Barrier cleared to design flow
Debristhan 20% of the openings in the barrier.capacity.
MetalDamaged/Bars are bent out of shape more than 3 Bars in placewith no bends more
Missinginches.than 3/4 inch.
Bars.
Bars are missing or entire barrierBars in place according to design.
missing.
Bars are looseand rust is causing 50%Barrier replaced or repaired to
deterioration to anypart of barrier.design standards.
Inlet/OutletDebrisbarrier missing or not attached to Barrier firmly attached to pipe
Pipepipe
February 2005Volume V – Runoff Treatment BMPs 4-37
No. 18 – Catchbasin Inserts
MaintenanceDefectConditionsWhen Maintenance isResults Expected When
ComponentNeededMaintenance is Performed
GeneralSedimentWhen sediment forms a cap over the No sediment cap on the insert
Accumulationinsert media of the insert and/or unit. media and its unit.
TrashandTrash and debris accumulates on insert Trash and debris removed
Debrisunit creating a blockage/restriction.from insert unit. Runoff freely
Accumulationflows into catch basin.
Media Insert Not Effluentwater from media insert has a Effluentwater from media
Removing Oil visible sheen.insert is free of oils and has no
visible sheen.
MediaInsertCatch basin insert is saturated withwaterRemove and replace media
Water Saturated and no longerhas the capacity to insert
absorb.
MediaInsert-OilMedia oil saturated due to petroleum spillRemove and replace media
Saturatedthat drains into catch basin. insert.
Media Insert Use Media has been used beyond the typicalRemove and replace media at
Beyond Normalaverage life of media insert product.regular intervals, depending on
Product Life insert product.
4-50Volume V – Runoff Treatment BMPs February 2005
Appendix A
WWHM3 Report
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
Preliminary DrainageReport September, 2015
LSA No. 5537
Western Washington Hydrology Model
PROJECT REPORT
___________________________________________________________________
Project Name:
Infiltration
Site Address:
City :
Report Date :
9/30/2015
MGS Regoin :
Puget East
Data Start :
1939/10/1
Data End :
2097/08/31
DOT Data Number:
03
WWHM3 Version:
___________________________________________________________________
PREDEVELOPED LAND USE
Name :
Basin 1
Bypass:
No
GroundWater:
No
Pervious Land UseAcres
C, Forest, Mod 1
Impervious Land UseAcres
___________________________________________________________________
Element Flows To:
Surface Interflow Groundwater
___________________________________________________________________
Name :
Basin 1
Bypass:
No
GroundWater:
No
Pervious Land UseAcres
A B, Lawn, Flat .252
Impervious Land UseAcres
DRIVEWAYS FLAT 0.748
___________________________________________________________________
Element Flows To:
Surface Interflow Groundwater
Gravel Trench Bed 1, Gravel Trench Bed 1,
___________________________________________________________________
Name :
Gravel Trench Bed 1
Bottom Length:
324ft.
Bottom Width :
5ft.
Trench bottom slope 1:
0.02 To 1
Trench Left side slope 0:
0 To 1
Trench right side slope 2:
0 To 1
Material thickness of first layer :
7
Pour Space of material for first layer :
0.333
Material thickness of second layer :
0
Pour Space of material for second layer :
0
Material thickness of third layer :
0
Pour Space of material for third layer :
0
Infiltration On
Infiltration rate :
2
Infiltration saftey factor :
1
Discharge Structure
Riser Height:
7 ft.
Riser Diameter:
6 in.
Element Flows To:
Outlet 1 Outlet 2
___________________________________________________________________
Gravel Trench Bed Hydraulic Table
Stage(ft) Area(acr) Volume(acr-ft) Dschrg(cfs) Infilt(cfs)
0.000 0.037 0.000 0.000 0.000
0.089 0.0370.001 0.000 0.075
0.178 0.037 0.002 0.000 0.075
0.267 0.037 0.003 0.000 0.075
0.356 0.037 0.004 0.000 0.075
0.444 0.037 0.006 0.000 0.075
0.533 0.037 0.007 0.000 0.075
0.622 0.037 0.008 0.000 0.075
0.711 0.037 0.009 0.000 0.075
0.800 0.037 0.010 0.000 0.075
0.889 0.037 0.011 0.000 0.075
0.978 0.037 0.012 0.000 0.075
1.067 0.037 0.013 0.000 0.075
1.156 0.037 0.014 0.000 0.075
1.244 0.037 0.015 0.000 0.075
1.333 0.037 0.017 0.000 0.075
1.422 0.037 0.018 0.000 0.075
1.511 0.037 0.019 0.000 0.075
1.600 0.037 0.020 0.000 0.075
1.689 0.037 0.021 0.000 0.075
1.778 0.037 0.022 0.000 0.075
1.867 0.037 0.023 0.000 0.075
1.956 0.037 0.024 0.000 0.075
2.044 0.037 0.025 0.000 0.075
2.133 0.037 0.026 0.000 0.075
2.222 0.037 0.028 0.000 0.075
2.311 0.037 0.029 0.000 0.075
2.400 0.037 0.030 0.000 0.075
2.489 0.037 0.031 0.000 0.075
2.578 0.037 0.032 0.000 0.075
2.667 0.037 0.033 0.000 0.075
2.7560.037 0.034 0.000 0.075
2.844 0.037 0.035 0.000 0.075
2.933 0.037 0.036 0.000 0.075
3.022 0.037 0.037 0.000 0.075
3.111 0.037 0.039 0.000 0.075
3.200 0.037 0.040 0.000 0.075
3.289 0.037 0.041 0.000 0.075
3.378 0.037 0.042 0.000 0.075
3.467 0.037 0.043 0.000 0.075
3.556 0.037 0.044 0.000 0.075
3.644 0.037 0.045 0.000 0.075
3.733 0.037 0.046 0.000 0.075
3.822 0.037 0.047 0.000 0.075
3.911 0.037 0.048 0.000 0.075
4.000 0.037 0.050 0.000 0.075
4.089 0.037 0.051 0.000 0.075
4.178 0.037 0.052 0.000 0.075
4.267 0.037 0.053 0.000 0.075
4.356 0.037 0.054 0.000 0.075
4.444 0.037 0.055 0.000 0.075
4.533 0.037 0.056 0.000 0.075
4.622 0.037 0.057 0.000 0.075
4.711 0.037 0.058 0.000 0.075
4.800 0.037 0.059 0.000 0.075
4.889 0.037 0.061 0.000 0.075
4.978 0.037 0.062 0.000 0.075
5.067 0.037 0.063 0.000 0.075
5.156 0.037 0.064 0.000 0.075
5.244 0.037 0.065 0.000 0.075
5.333 0.037 0.066 0.000 0.075
5.422 0.037 0.067 0.000 0.075
5.511 0.037 0.068 0.000 0.075
5.600 0.037 0.069 0.000 0.075
5.689 0.037 0.070 0.000 0.075
5.778 0.037 0.072 0.000 0.075
5.867 0.037 0.073 0.000 0.075
5.956 0.037 0.074 0.000 0.075
6.044 0.037 0.075 0.000 0.075
6.133 0.037 0.076 0.000 0.075
6.222 0.037 0.077 0.000 0.075
6.311 0.037 0.078 0.000 0.075
6.400 0.037 0.079 0.000 0.075
6.489 0.037 0.080 0.000 0.075
6.578 0.037 0.081 0.000 0.075
6.667 0.037 0.083 0.000 0.075
6.756 0.037 0.084 0.000 0.075
6.844 0.037 0.085 0.000 0.075
6.933 0.037 0.086 0.000 0.075
7.022 0.037 0.089 0.016 0.075
7.111 0.037 0.093 0.180 0.075
7.200 0.037 0.096 0.436 0.075
7.289 0.037 0.099 0.756 0.075
7.378 0.037 0.102 1.131 0.075
7.467 0.037 0.106 1.552 0.075
7.556 0.037 0.109 2.016 0.075
7.6440.037 0.112 2.519 0.075
7.733 0.037 0.116 3.058 0.075
7.822 0.037 0.119 3.631 0.075
7.911 0.037 0.122 4.235 0.075
8.000 0.037 0.126 4.869 0.075
___________________________________________________________________
MITIGATED LAND USE
___________________________________________________________________
ANALYSIS RESULTS
Flow Frequency Return Periods for Predeveloped. POC #1
Return PeriodFlow(cfs)
2 year
0.015685
5 year
0.026919
10 year
0.03429
25 year
0.047129
50 year
0.057521
100 year
0.064075
Flow Frequency Return Periods for Mitigated. POC #1
Return PeriodFlow(cfs)
2 year
0
5 year
0
10 year
0
25 year
0
50 year
0
100 year
0
___________________________________________________________________
Yearly Peaks for Predeveloped and Mitigated. POC #1
Year Predeveloped Mitigated
1941 0.023 0.000
1942 0.008 0.000
1943 0.021 0.000
1944 0.009 0.000
1945 0.003 0.000
1946 0.027 0.000
1947 0.017 0.000
1948 0.018 0.000
1949 0.031 0.000
1950 0.0150.000
1951 0.064 0.000
1952 0.025 0.000
1953 0.006 0.000
1954 0.008 0.000
1955 0.014 0.000
1956 0.006 0.000
1957 0.0160.000
1958 0.012 0.000
1959 0.015 0.000
1960 0.016 0.000
1961 0.018 0.000
1962 0.016 0.000
1963 0.008 0.000
1964 0.008 0.000
1965 0.014 0.000
1966 0.019 0.000
1967 0.012 0.000
1968 0.030 0.000
1969 0.015 0.000
1970 0.015 0.000
1971 0.012 0.000
1972 0.013 0.000
1973 0.040 0.000
1974 0.013 0.000
1975 0.022 0.000
1976 0.020 0.000
1977 0.018 0.000
1978 0.001 0.000
19790.014 0.000
1980 0.015 0.000
1981 0.022 0.000
1982 0.007 0.000
1983 0.022 0.000
1984 0.015 0.000
1985 0.015 0.000
19860.010 0.000
1987 0.034 0.000
1988 0.029 0.000
1989 0.015 0.000
1990 0.018 0.000
1991 0.059 0.000
1992 0.047 0.000
1993 0.013 0.000
1994 0.011 0.000
1995 0.007 0.000
1996 0.019 0.000
1997 0.047 0.000
1998 0.028 0.000
1999 0.010 0.000
20000.028 0.000
2001 0.014 0.000
2002 0.006 0.000
2003 0.013 0.000
2004 0.034 0.000
2005 0.006 0.000
2006 0.013 0.000
20070.017 0.000
2008 0.012 0.000
2009 0.022 0.000
2010 0.036 0.000
2011 0.023 0.000
2012 0.027 0.000
2013 0.018 0.000
20140.043 0.000
2015 0.017 0.000
2016 0.010 0.000
2017 0.032 0.000
2018 0.009 0.000
2019 0.016 0.000
2020 0.016 0.000
2021 0.011 0.000
2022 0.027 0.000
2023 0.007 0.000
2024 0.016 0.000
2025 0.013 0.000
2026 0.028 0.000
2027 0.020 0.000
20280.016 0.000
2029 0.020 0.000
2030 0.015 0.000
2031 0.023 0.000
2032 0.019 0.000
2033 0.034 0.000
2034 0.008 0.000
20350.040 0.000
2036 0.018 0.000
2037 0.016 0.000
2038 0.000 0.000
2039 0.012 0.000
2040 0.009 0.000
2041 0.032 0.000
20420.018 0.000
2043 0.020 0.000
2044 0.029 0.000
2045 0.011 0.000
2046 0.013 0.000
2047 0.017 0.000
2048 0.010 0.000
2049 0.008 0.000
2050 0.011 0.000
2051 0.015 0.000
2052 0.013 0.000
2053 0.008 0.000
2054 0.038 0.000
2055 0.005 0.000
20560.030 0.000
2057 0.053 0.000
2058 0.057 0.084
2059 0.020 0.000
2060 0.022 0.000
2061 0.008 0.000
2062 0.018 0.000
20630.072 0.000
2064 0.014 0.000
2065 0.026 0.000
2066 0.011 0.000
2067 0.005 0.000
2068 0.018 0.000
2069 0.039 0.000
20700.010 0.000
2071 0.007 0.000
2072 0.008 0.000
2073 0.010 0.000
2074 0.041 0.000
2075 0.022 0.000
2076 0.004 0.000
20770.025 0.000
2078 0.001 0.000
2079 0.007 0.000
2080 0.011 0.000
2081 0.044 0.000
2082 0.019 0.000
2083 0.026 0.000
2084 0.016 0.000
2085 0.019 0.000
2086 0.012 0.000
2087 0.016 0.000
2088 0.016 0.000
2089 0.010 0.000
2090 0.017 0.000
2091 0.0100.000
2092 0.016 0.000
2093 0.032 0.000
2094 0.006 0.000
2095 0.006 0.000
2096 0.011 0.000
2097 0.013 0.000
2098 0.0320.000
___________________________________________________________________
Ranked Yearly Peaks for Predeveloped and Mitigated. POC #1
Rank Predeveloped Mitigated
1 0.0720 0.0841
2 0.0643 0.0000
3 0.0586 0.0000
4 0.0570 0.0000
5 0.0534 0.0000
6 0.0474 0.0000
7 0.0471 0.0000
8 0.0444 0.0000
9 0.0425 0.0000
10 0.0410 0.0000
11 0.0404 0.0000
12 0.0398 0.0000
13 0.0387 0.0000
14 0.0375 0.0000
15 0.0358 0.0000
16 0.0344 0.0000
17 0.0341 0.0000
18 0.0340 0.0000
19 0.0325 0.0000
20 0.0324 0.0000
21 0.0323 0.0000
22 0.0317 0.0000
23 0.03110.0000
24 0.0298 0.0000
25 0.0295 0.0000
26 0.0295 0.0000
27 0.0289 0.0000
28 0.0282 0.0000
29 0.0281 0.0000
30 0.02750.0000
31 0.0271 0.0000
32 0.0269 0.0000
33 0.0266 0.0000
34 0.0260 0.0000
35 0.0257 0.0000
36 0.0250 0.0000
37 0.0249 0.0000
38 0.0234 0.0000
39 0.0233 0.0000
40 0.0232 0.0000
41 0.0224 0.0000
42 0.0224 0.0000
43 0.0221 0.0000
44 0.0218 0.0000
45 0.0218 0.0000
46 0.0215 0.0000
47 0.0206 0.0000
48 0.0204 0.0000
49 0.0201 0.0000
50 0.0200 0.0000
51 0.0198 0.0000
52 0.0195 0.0000
53 0.0194 0.0000
54 0.0192 0.0000
55 0.0187 0.0000
56 0.0186 0.0000
57 0.01850.0000
58 0.0183 0.0000
59 0.0182 0.0000
60 0.0181 0.0000
61 0.0180 0.0000
62 0.0179 0.0000
63 0.0179 0.0000
64 0.0178 0.0000
65 0.0176 0.0000
66 0.0175 0.0000
67 0.0173 0.0000
68 0.0171 0.0000
69 0.0169 0.0000
70 0.0166 0.0000
71 0.0165 0.0000
72 0.0165 0.0000
73 0.0164 0.0000
74 0.0163 0.0000
75 0.0163 0.0000
76 0.0162 0.0000
77 0.0161 0.0000
78 0.0158 0.0000
79 0.0158 0.0000
80 0.0157 0.0000
81 0.0157 0.0000
82 0.0156 0.0000
83 0.0155 0.0000
84 0.01550.0000
85 0.0155 0.0000
86 0.0155 0.0000
87 0.0154 0.0000
88 0.0152 0.0000
89 0.0149 0.0000
90 0.0149 0.0000
91 0.0148 0.0000
92 0.0147 0.0000
93 0.0146 0.0000
94 0.0144 0.0000
95 0.0142 0.0000
96 0.0140 0.0000
97 0.0140 0.0000
98 0.0136 0.0000
99 0.0134 0.0000
100 0.0133 0.0000
101 0.0132 0.0000
102 0.0131 0.0000
103 0.0130 0.0000
104 0.0129 0.0000
105 0.0127 0.0000
106 0.0126 0.0000
107 0.0126 0.0000
108 0.0122 0.0000
109 0.0121 0.0000
110 0.0120 0.0000
111 0.01190.0000
112 0.0117 0.0000
113 0.0116 0.0000
114 0.0114 0.0000
115 0.0113 0.0000
116 0.0110 0.0000
117 0.0110 0.0000
118 0.0109 0.0000
119 0.0106 0.0000
120 0.0105 0.0000
121 0.0104 0.0000
122 0.0102 0.0000
123 0.0100 0.0000
124 0.0099 0.0000
125 0.0099 0.0000
126 0.0098 0.0000
127 0.0097 0.0000
128 0.0096 0.0000
129 0.0090 0.0000
130 0.0086 0.0000
131 0.0086 0.0000
132 0.0085 0.0000
133 0.0082 0.0000
134 0.0082 0.0000
135 0.0081 0.0000
136 0.0081 0.0000
137 0.0080 0.0000
138 0.00770.0000
139 0.0076 0.0000
140 0.0076 0.0000
141 0.0074 0.0000
142 0.0074 0.0000
143 0.0072 0.0000
144 0.0069 0.0000
145 0.0069 0.0000
146 0.0065 0.0000
147 0.0064 0.0000
148 0.0064 0.0000
149 0.0063 0.0000
150 0.0060 0.0000
151 0.0058 0.0000
152 0.0054 0.0000
153 0.0046 0.0000
154 0.0035 0.0000
155 0.0034 0.0000
156 0.0014 0.0000
157 0.0008 0.0000
158 0.0002 0.0000
___________________________________________________________________
POC #1
The Facility PASSED.
Flow(CFS) Predev Dev Percentage Pass/Fail
0.0078 15906 2 0 Pass
0.0083 13843 2 0 Pass
0.0088 12167 2 0Pass
0.0093 10748 2 0 Pass
0.0098 9517 2 0 Pass
0.0104 8475 2 0 Pass
0.0109 7586 2 0 Pass
0.0114 6801 2 0 Pass
0.0119 6092 2 0 Pass
0.0124 5433 2 0 Pass
0.0129 4841 2 0 Pass
0.0134 4372 2 0 Pass
0.0139 3926 2 0 Pass
0.0144 3511 2 0 Pass
0.0149 3166 2 0 Pass
0.0154 2863 2 0Pass
0.0159 2609 2 0 Pass
0.0164 2384 2 0 Pass
0.0169 2161 2 0 Pass
0.0174 1985 2 0 Pass
0.0179 1827 2 0 Pass
0.0184 1681 2 0 Pass
0.0189 15572 0 Pass
0.0194 1447 2 0 Pass
0.0199 1346 2 0 Pass
0.0204 1244 2 0 Pass
0.0209 1155 2 0 Pass
0.0214 1075 2 0 Pass
0.0219 998 2 0 Pass
0.0224933 2 0 Pass
0.0229 879 2 0 Pass
0.0234 836 2 0 Pass
0.0239 789 2 0 Pass
0.0244 742 2 0 Pass
0.0249 700 2 0 Pass
0.0254 661 2 0 Pass
0.0259 617 2 0 Pass
0.0264 573 2 0 Pass
0.0269 537 2 0 Pass
0.0274 504 2 0 Pass
0.0279 469 2 0 Pass
0.0284 445 2 0Pass
0.0289 415 2 0 Pass
0.0294 399 2 0 Pass
0.0299 373 2 0 Pass
0.0304 346 2 0 Pass
0.0309 327 2 0 Pass
0.0314 304 2 0 Pass
0.0319 2862 0 Pass
0.0324 260 2 0 Pass
0.0329 245 2 0 Pass
0.0334 226 2 0 Pass
0.0339 212 2 0 Pass
0.0344 193 2 1 Pass
0.0349 179 2 1 Pass
0.0354162 2 1 Pass
0.0359 147 2 1 Pass
0.0364 128 2 1 Pass
0.0369 117 2 1 Pass
0.0374 102 2 1 Pass
0.0380 95 2 2 Pass
0.0385 84 2 2 Pass
0.0390 79 2 2 Pass
0.0395 73 2 2 Pass
0.0400 64 2 3 Pass
0.0405 57 2 3 Pass
0.0410 47 2 4 Pass
0.0415 43 2 4Pass
0.0420 38 2 5 Pass
0.0425 34 2 5 Pass
0.0430 31 2 6 Pass
0.0435 27 2 7 Pass
0.0440 27 2 7 Pass
0.0445 23 2 8 Pass
0.0450 212 9 Pass
0.0455 18 2 11 Pass
0.0460 16 2 12 Pass
0.0465 13 2 15 Pass
0.0470 12 2 16 Pass
0.0475 10 2 20 Pass
0.0480 10 2 20 Pass
0.048510 2 20 Pass
0.0490 10 2 20 Pass
0.0495 10 2 20 Pass
0.0500 10 2 20 Pass
0.0505 10 2 20 Pass
0.0510 9 2 22 Pass
0.0515 9 2 22 Pass
0.0520 9 2 22 Pass
0.0525 9 2 22 Pass
0.0530 9 2 22 Pass
0.0535 8 2 25 Pass
0.0540 7 2 28 Pass
0.0545 7 2 28 Pass
0.0550 7 2 28 Pass
0.0555 6 2 33 Pass
0.0560 5 2 40 Pass
0.0565 5 2 40 Pass
0.0570 5 2 40 Pass
0.0575 4 2 50 Pass
_____________________________________________________
___________________________________________________________________
Water Quality BMP Flow and Volume for POC 1.
0.0328 acre-feet
On-line facility volume:
0.01
On-line facility target flow:cfs.
0.2175
Adjusted for 15 min:cfs.
0.103
Off-line facility target flow:cfs.
0.1164
Adjusted for 15 min:cfs.
___________________________________________________________________
Perlnd and Implnd Changes
No changes have been made.
___________________________________________________________________
This program and accompanying documentation is provided 'as-is' without warranty of any kind. The
entire risk regarding the performance and results of this program is assumed by the user. Clear Creek
Solutions and the Washington State Department of Ecology disclaims all warranties, either expressed
or implied, including but not limited to implied warranties of program and accompanying documentation.
In no event shall Clear Creek Solutions and/or the Washington State Department of Ecology be liable
for any damages whatsoever(including without limitation to damages for loss of business profits, loss
of business information, business interruption, and the like) arising out of the use of, or inability
to use this program even if Clear Creek Solutions or the Washington State Department of Ecology has
been advised of the possibility of such damages.
Appendix B
Custom Soil Resource Report
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
Preliminary DrainageReport September, 2015
LSA No. 5537
Appendix C
Geotechnical Report
Lovell-Sauerland and Associates Brackett’s Corner Redevelopment.
Preliminary DrainageReport September, 2015
LSA No. 5537