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Drainage Report
Shearer Brothers Chipping, LLC.
Industrial Property
100 NE Katchemak Lane, Belfair
Parcel No. 12321-13-90051
Mason County, Washington
May 16, 2012
Project#1251
Prepared For:
Shearer Brothers Chipping, LLC
PO Box 2638
Belfair, Washington 98528 titi CLYDE S
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Prepared By: �`L`�` of wnsy��c 9�
Envirotech Engineering —
PO Box 984
Belfair, Washington 98528 �oX �F�s°ERA°
Phone: 360-275-9374 �sSIONALE�G�
Fax: 360-275-4789
TABLE OF CONTENTS
1.0 PROJECT DESCRIPTION...................................................................................................................1
2.0 EXISTING CONDITIONS....................................................................................................................2
2.1 TOPOGRAPHY AND GEOMORPHOLOGY..............................................................................................2
2.2 SURFACE DRAINAGE...........................................................................................................................2
3.0 INFILTRATION RATES/SOILS REPORTS....................................................................................3
3.1 SUBSURFACE CONDITIONS..................................................................................................................3
3.1.1 Groundwater...............................................................................................................................3
3.2 SOILS TESTING AND PROPERTIES.......................................................................................................3
3.3 INFILTRATION RATES.........................................................................................................................4
4.0 HYDROLOGIC/HYDRAULIC INFORMATION............................................................................5
4.1 HYDROLOGIC SUMMARY....................................................................................................................5
4.2 BEST MANAGEMENT PRACTICES.......................................................................................................5
4.3 DRAINAGE TRIBUTARY TO THE PROJECT..........................................................................................5
4.4 DRAINAGE SYSTEM BEYOND THE PROJECT.......................................................................................5
4.5 CRITICAL AREAS—WELLS—SEPTICS-AQUIFERS............................................................................6
4.6 FLOOD ANALYSIS................................................................................................................................6
5.0 FACILTY SIZING AND DOWNSTREAM ANALYSIS...................................................................7
5.1 BIO-INFILTRATION SWALE.................................................................................................................7
5.2 CATCH/PRE-SETTLING BASIN............................................................................................................7
5.3 SAND INFILTRATION...........................................................................................................................7
5.4 ROOF DOWNSPOUT INFILTRATION.....................................................................................................7
6.0 CONSTRUCTION SEQUENCE AND PROCEDURE.......................................................................8
7.0 PERMANENT EROSION CONTROL AND SITE RESTORATION..............................................9
7.1 PARKING SURFACE..............................................................................................................................9
7.2 B[OFILTRATION...................................................................................................................................9
7.3 PERMANENT SEEDING.......................................................................................................................10
8.0 INSPECTION AND MAINTENANCE..............................................................................................12
9.0 CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS.....................................................13
10.0 PROJECT ENGINEER'S CERTIFICATION................................................................................14
Appendices
Appendix A—Site Map
Appendix B—Hydrologic Information
Appendix C—Best Management Practices
1.0 PROJECT DESCRIPTION
Envirotech Engineering (Envirotech) has completed this drainage report in conjunction with the
stormwater management plan for an industrial property located at 100 NE Katchemak Lane,
parcel number 12321-13-90051 in Mason County, Washington (Project). See the Vicinity Map
below for a general indication of the Project location.
Information pertaining to the Project was provided by the proponent of the property, and
observations from a field visit by Envirotech. The property is currently developed with a
mechanic/ work shop, onsite septic, liquid storage tanks, swales, retention Pond, fencing, and
natural surfaced parking lot. The proposed development is expected to consist of a 120 x 60
building to be used as a dry storage facility. Approximate site development with relation to
existing site features are illustrated in the Site Map in Appendix A.
It is anticipated that the new building will cover approximately 7200 square feet (sf). Including
adjacent storage and roof overhang, the roof area will be about 9260 sf. The existing ingress/
egress and parking area encompasses about 63,815 s£The total proposed impervious surface area
is the new building (9260 sf). Considering both proposed and existing impervious surfaces, the
area is approximately 82,950 sf. The total land area that is anticipated to be disturbed as a result
of development is 0.28 acres.Cut and fill quantities were approximated to be 130 cubic yards c
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and 40 cy, respectively. See the accompanying stormwater management plans for an illustration
of current and proposed site features.
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Vicinity Map from Mason County Website
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 1 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
2.0 EXISTING CONDITIONS
The Project is currently developed as previously mentioned, and surrounded by rural residential
and commercial development. Katchemak Lane extends just beyond the south side of the
property, and a US Naval railroad is located to the west of the property. Vegetation on and near
the property consists primarily of 2°d growth firs, and other trees and shrubbery common to this
area of the Pacific Northwest. The property is mostly cleared in conjunction with the existing
development. An aerial photo of the Project and immediate vicinity is provided on the following
page.
2.1 Topography and Geomorphology
The topographic information provided in this section was extrapolated from a public lidar source,
and incorporated observations and field measurements. Where necessary, slope verification
included measuring slope lengths and inclinations with a cloth tape and inclinometer. See the Site
Map in Appendix A for an illustration of the general slope indicators with respect to the planned
development.
Except for the railroad embankment, descending slopes exceeding 15%were not observed within
300 feet of the property.Natural slopes with grades averaging 10%were observed approximately
150 feet to the west of the property.
Ascending grades are generally located to the east and southeast of the planned development. The
immediate slope has been cut to approximately 2:1 with a vertical relief of up to 15 feet. Natural
ascending slopes with grades exceeding 15% were not observed within 300 feet of the Project.
The upland area of the property is situated on a gentle sloping hillside near a crest. Landforms are
primarily of glacial origin.
2.2 Surface Drainage
The majority of the stormwater runoff originating upslope from the anticipated development is
expected to be minimal. The upland watershed is very small. Significant scour, erosion and
sediment transport was not apparent on the Project. There are no apparent water bodies or
wetlands located upslope from the planned development that would significantly influence the
Project.
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 2 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
3.0 INFILTRATION RATES/SOILS REPORTS
Information on infiltration rates and soil conditions pertaining to the Project was accomplished by
Envirotech. For complete details, see the Geological Assessment prepared for the Shearer
Brothers Chipping, LLC. Industrial Property, dated April 30, 2012. Selected information
pertaining to the drainage aspect of the project is provided below.
3.1 Subsurface Conditions
The following subsurface conditions are estimated descriptions of the Project subgrade utilizing
information from the depth of penetration at all testing, sampling, observed and investigated
locations. Specifically, soils for this project were described utilizing the Unified Soil
Classification System (USCS), Soil Conservation Service (SCS), and the U.S. Department of
Agriculture(USDA)Textural Classification System.
The Project is composed of native soils with no indications of significant borrowed fill. For
engineering purposes,these native soils consist of distinguishable layers, as presented below.
Soils within the upper 10 feet of natural ground were primarily observed to be moist, brown
poorly graded sand with some gravel(SP).
According to the "Soil Survey of Mason County," by the United States Department of
Agriculture, Soil Conservation Service, the upland site soils are described as Indianola Loamy
Sand, Ib with 5%to 15% slopes. The soil designation is depicted in the aerial photograph below,
and complete descriptions are provided in Appendix B of this report.
According to the USDA Textural Classification System, the site soils are primarily classified as
medium sand. Soil structure may be described as granular.
3.1.1 Groundwater
From the water well report(s)and knowledge of the general area, permanent groundwater
is approximately 100 feet directly below the property at the lowest building pad location.
Perched groundwater at shallow depths was not observed on-site, nor indicated on the
well reports.
3.2 Soils Testing and Properties
The soil samples obtained at the Project site during the field investigation were preserved and
transported for possible laboratory testing. Visual classification of soils was performed in the
field at all observed soil profiles. Visual classifications were performed in accordance with the
American Standards for Testing and Materials(ASTM D2488).
The general results from the visual classification are presented above in the Subsurface
Conditions Section. Specifically,soils within the upper 10 feet in one testing location consisted of
approximately 5% gravel, 95% medium sand-sized soils, and nearly 0% fines with no plasticity.
Minor variations observed during the visual classification of particle size content (i.e. gravel,
sand, fines), or isolated pockets within the soil stratification were insignificant in relation to the
Envirotech Engineering Shearer Brothers Chipping, LLC Drainage Report
PO Box 984 page 3 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
overall engineering properties of the soil. The soil gradation meets the requirements for pollution
liners per the 2005 Department of Ecology Stormwater Manual.
Based on the fines content,erodibility of the site soils is considered to be low. Based on the fines
content and fraction of clay within the fines content, settleability of the site soils is expected to be
moderate to fast. Permeability is expected to be high for this site due significance of moderate
density,poorly graded granular soils.
3.3 Infiltration Rates
According to the 2005 Stormwater Management Manual for Western Washington prepared by the
Washington State Department of Ecology Water Quality Program, infiltration rates are
determined per the USDA Textural Classification of the soils, and an appropriate factor of safety.
Based on the soils consisting predominantly sand, and utilizing a factor of safety of 2, site
infiltration for stormwater facilities should be 2 inches/hour.
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 4 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
4.0 HYDROLOGIC/HYDRAULIC INFORMATION
4.1 Hydrologic Summary
The Santa Barbara Urban Hydrograph (SBUH) method was utilized for estimating peak design
flows. The SBUH method is based on a runoff curve number approach, and uses Soil
Conservation Service (SCS) equations for computing soil absorption and precipitation excess.
This analysis is based on a Type IA rainfall distribution and a 24 hour storm duration.
The following design parameters were used for stormwater drainage design:
• Design storm for water quality, 6mo-24hr(2.7 inches);
• Design storm for erosion control,2yr-24hr(3.6 inches);
• Design storm for stability, 100yr-24hr(7.5 inches);
• Hydraulic soil group `C'
• Curve Number of 98 for impervious areas; and,
• Curve Number of 36 for pre-existing conditions.
4.2 Best Management Practices
Best Management Practices (BMPs) for this project includes vegetated bio swales, a vegetated
retention pond, oil/water separator, roof infiltration system, and sand lined treatment system. The
proposed developmental areas of the property are relatively flat. Stormwater originating from the
roof will be tight-lined to the infiltration system. Runoff from the primary parking area is
currently directed to a series of bio swales before entering a vegetated retention pond. For the
existing development, collection and treatment of pollution from the mechanic shop is currently
channeled to an oil/ water separator before entering the sand infiltration system. Besides the
vegetated drainage systems, permanent vegetation is required in all denuded areas. Natural
drainage patterns are to be maintained to the maximum extents practicable. See the BMP's
located in Appendix C of this report for applicable provisions to be adhered to for pollution and
dust.
4.3 Drainage Tributary to the Project
The upslope watershed is relatively small, only about 100 feet from the property, and has low to
slightly sloping grades. Stormwater entering the site appears to be negligible.
4.4 Drainage System Beyond the Project
Most of the natural drainage from the site appears to be infiltrated within the high percolating
soils on-site. Most of the developed area of the project is within an earth cut. Due to this,and the
railroad embankment located immediately downslope of the property, it appears that negligible
stormwater leaves the property. This project is within the Hood Canal watershed.
Off-site analysis and/or mitigation is not deemed necessary for this Project. This is based on the
scale of the proposed Project,and the expected low impact to downstream properties.This project
has been designed to retain all stormwater generated by new and existing development during a
100-yr 24-hr storm event.
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 5 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
4.5 Critical Areas—Wells—Septics-Aquifers
This project is not anticipated to disturb any critical area, and special requirements other than
what is provided in the stormwater management plan are not required.
4.6 Flood Analysis
This project is not situated within a flood zone (per FEMA flood mapping), or contain or abut a
stream that could influence the development, therefore an analysis of the 100-year flood is not
required.
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 6 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
III
5.0 FACILTY SIZING AND DOWNSTREAM ANALYSIS
Proposed facilities for this project include bio Swale and infiltration facilities. The following
subsections provide design information for these drainage features.
5.1 Bio-Infiltration Swale
The drainage swale that extends along the west side of the property was designed to be increased
in order to accommodate the 6 month 24 hour water quality storm originating from the parking
lot. The bio-filtration swale is 1.5 feet in depth, has a bottom width of 2.5 feet, and side slopes of
3:1. Section 4.1 of this report depicts the hydrologic summary of parameters used in the SBUH
analysis method.
For runoff treatment from parking areas, the 6mo-24hr storm event was estimated to be, Q= 1.1
cfs. For quantity control,the 100yr 24hr runoff was estimated to be Q=3.1 cfs.
The following is a summary of biofiltration swale design parameters:
•Biofilter length: 420+ft
•Biofilter bottom width: 2.5 ft
-Design flow water depth for 6mo storm: 4 in
Design flow velocity:4 fps
-Flow line slopes: —1%to 2%
-Side slopes: 3:1 (horizontal:vertical)
-Mannings"n"for treatment: 0.07
Based on conservative swale parameters, the swale may accommodate at least 2 cfs of the
required 3.1 cfs. The remaining 1.1 cfs of flow is directed to the existing retention basin and
additional head height above the facilities since overflow will remain on-site.
5.2 Catch/Pre-settling Basin
The existing catch/ presettling basin is on-line with the sand infiltration system, and can
accommodate the 25yr-24hr design storm from the existing concrete pad without difficulty.
5.3 Sand Infiltration
Based on the governing storm water manual for runoff collection and infiltration trench
distribution, the runoff from the concrete pad pollution generating surface may be directed to a
sand lined infiltration. The native on-site soil classification is medium sand with the
characteristics allowed by the stormwater manual.Additional area is not required.
5.4 Roof Downspout Infiltration
Based on the governing storm water manual, the runoff from each 1000 sf of roof area shall be
directed to a standard 2 feet wide trench at 30 feet in length. The resulting trench infiltrative area
for the 9260 sf of roof area, and the soils classification on-site is 556 sf, which excludes trench
sides for conservative purposes.
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 7 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
6.0 CONSTRUCTION SEQUENCE AND PROCEDURE
The following includes the recommended construction sequence and procedure for project
development:
1. Delineate clearing and easement limits.
2. Construct all required temporary erosion control features.
3. Clear vegetation required for site development.
4. Perform initial earthwork and rough grading for constructing the building pad,
stormwater management facilities, etc. If necessary, exposed soils in stock piles must be
protected with plastic covering or County approved method.
5. Complete final grading of the subgrade, and materials placement per the plans and
specifications. This includes dredging sediments from temporary sediment facilities, if
necessary.
6. Maintain all temporary erosion and sediment control facilities, as needed, in order to
provide the required protection of downstream water quality. Additional temporary
erosion control shall be rendered throughout the duration of the project, if necessary.
7. Provide permanent erosion control in order to stabilize the project.
8. Remove temporary erosion sedimentation control facilities after construction is complete,
and the site is sufficiently stabilized.
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 8 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
J
7.0 PERMANENT EROSION CONTROL AND SITE RESTORATION
Site restoration and permanent erosion control includes vegetation, mulching (if necessary), and
other standard protocol. Specific details regarding permanent erosion are illustrated on the
drawing sheets.
All cut and fill slopes shall be stabilized according to sheet 2 of the design plans. This includes
temporary stabilization when necessary,and permanent erosion control.
7.1 Parking Surface
The existing native sand surfaced parking lot is acceptable with ordinary maintenance. The
parking shall maintain a slope of 2% in order to direct most of the stormwater runoff into the
adjacent drainage swales. Dust must be kept at a minimum. See the BMP's for Dust Control for
Unpaved Parldng Lots in Appendix C of this report.
71 Biofiltration
The biofiltration swale adjacent to north side of the proposed driveway will be permanently
stabilized with grasses. See sheet 3 of the engineering plans and specifications for specific details
and specifications. Either hydroseeding per the plans, or the following may be used for
biofiltration:
1. TOP SOIL WITH THE FOLLOWING SOIL MIXTURE REQUIREMENTS SHALL BE
PLACED AS THE UPPER 18 INCHES OF THE SWALE IN ORDER TO REDUCE THE
INFILTRATION RATE: 50-801/o SANDY LOAM, 10-20%CLAY AND 10-20%
COMPOSTED ORGANIC MATTER.
2. SWALE SHALL BE GRASS LINED. SEE THE FOLLOWING RECOMMENDATIONS:
COMMON NAME PERSISTENCE/GROWTH FORM DESCRIPTION
ANNUAL RYEGRASS COMMON EROSION CONTROL
GRASS; ESTABLISHES ON
OR ITALIAN RYE ANNUALBUNCHGRASS BARE SOILS BUT
GRASS DOES NOT RESEED
WELL
KENTUCKY PERENNIAL/SOD-FORMING COMMON TURF
BLUEGRASS GRASS;MAY
NEED REGULAR RE-
SEEDING
TALL FESCUE PERRENNIALBUNCHGRASS COMMON TURF
GRASS;CAN BE
USED
ALONE;MAY
REQUIRE
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 9 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
IRRIGATION
IN DRY SEASON
WESTERN WHEAT PERENNIAL/SOD-FORMING TOLERATES
GRASS DROUGHT
OTHER RECOMMENDED GRASSES AND LEGUMES INCLUDES MEADOW FOXTAIL,
TIMOTHY, SEASIDE COLONIAL BENTGRASS,CREEPING RED FESCUE,WHITE
CLOVER,REDTOP,ROUGHSTALK BLUEGRASS AND PERRENIAL RYEGRASS.
INVASIVE SPECIES THAT SHALL NOT BE USED INCLUDES REED CANARY GRASS,
PURPLE LOOSESTRIFE,REEDS,YELLOW IRIS AND CATTAILS.
3. NO HEAVY OR PRO-LONGED SHADING OF THE BIOFILTER IS ALLOWED DUE TO
BUILDINGS AND/OR TREES.
4. VEGETATE THE GROUND UPSLOPE FROM THE GRASSED TREATMENT AREA OF
THE BIOFILTER TO PREVENT EROSION.USE ADDITIONAL GRASS OR NON-
AGGRESSIVE GROUND COVER.
5. IRRIGATION AND OTHER MAINTENANCE AS NECESSARY PROVIDED TO ESURE
THAT THE VEGETATION REMAINS VIABLE AND THAT A HARDY ROOT
STRUCTURE FORMS IN THE FIRST YEAR. IRRIGATE DURING DRY MONTHS AT A
RATE OF ONCE PER WEEK.
73 Permanent Seeding
The regenerative plan for this project includes permanent erosion control seeding in the disturbed
areas of the Project. Seeding specifications are provided in the construction plans, and
summarized below:
1.BEFORE SEEDING,INSTALL NEEDED SURFACE RUNOFF CONTROL MEASURES
SUCH AS GRADIENT TERRACES,INTERCEPTOR DIKES,SWALES,LEVEL
SPREADERS AND SEDIMENT BASINS.
2.THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE,FOLLOWING
SURFACE ROUGHENING.PERFORM ALL OPERATIONS ACCROSS OR
PERPENDICULAR TO THE SLOPE.
3. SEEDING MIXTURE SHALL BE AS SHOWN BELOW,AND SHALL BE APPLIED AT
THE RATE OF 120 POUNDS PER ACRE.
4. SEED BEDS PLANTED BETWEEN MAY 15 AND AUGUST 15 WILL REQUIRE
IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO FOSTER AND
PROTECT THE ROOT STRUCTURE.
5. SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30,ARMORING OF THE
SEED BED WILL BE NECESSARY,(e.g.,GEOTEXTILES,JUTE MAT,CLEAR PLASTIC
COVERING).
6.FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS'
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 10 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
RECOMMENDATIONS.AMOUNTS SHOULD BE MINIMIZED,ESPECIALLY ADJACENT
TO WATER BODIES AND WETLANDS.
USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION CONTROL,
OR A COUNTY APPROVED ALTERNATE SEED MIXTURE.
PROPORTIONS PURITY GERMINATION
NAME BY WEIGHT(%) (%) (%)
KENTUCKY BLUEGRASS(POA PRATENSIS) 15 85 80
PERENNIAL RYE(LOLIUM PERENNE) 30 95 90
CHEWING FESCUE 15 95 90
(FESTUCA RUBRA COMMUTATA)
(JAMESTOWN,BANNER, SHADOW,KOKET)
TALL FESCUE (FESTUCA ARUNDINCEA) 40 95 90
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 11 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
8.0 INSPECTION AND MAINTENANCE
Erosion and sediment control inspection and maintenance schedules are provided in the
Construction Stormwater Pollution Prevention Plan for this project. This section provides
information pertaining to permanent stormwater management facilities.
An operation and maintenance schedule for all permanent stormwater facilities and BMP's are
provided under a separate cover titled "Operation and Maintenance Manual for Shearer Brothers
Chipping,LLC. Industrial Property."An operation and maintenance Declaration of Covenant will
be required to cover all privately owned and maintained stormwater facilities. Performance
bonding, or other appropriate instrument, shall be required for this project to ensure compliance
with the standards presented in this report.
Inspection, maintenance, and financial liability of all stormwater management facilities shall be
the responsibility of the current property owner. Currently,the property owner(s)is the following:
Shearer Brothers Chipping, LLC.
PO Box 2638
Belfair, Washington 98528
360-426-5546
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 12 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
9.0 CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS
Upon completion of this project,the development is expected to render no more than 50 trips per
day of traffic. Although this is unknown, 50 trips is our conservative estimation based on number
of observed employees, and traffic during our site visits. Potential source of pollutants may occur
from spills, leaks, excessive usage, ordinary usage, or vandalism of several pollutants including
Fuel,Oil, Solvent,Degreaser,Dust, Pesticide,Herbacide, Fertilizer and Other Chemicals.
Pollutants associated with mechanic shops are currently on-site. The potential pollution sources
may be released into the stormwater due to the existing development of the property, and future
use of the facilities.
Control of pollutants other than sediments include the following:
• All pollutants other than sediments shall be handled and disposed of in a manner
that does not cause contamination of stormwater.
• Cover, containment and protection from vandalism shall be provided for all
chemicals, liquid products, petroleum products, and non-inert wastes present on the
project site. See the BMP's in Appendix C of this report such as "Loading and
Unloading Areas for Liquid or Solid Materials," Maintenance and Repair of
Vehicles and Equipment," "Spills of Oil and Hazardous Substances," and
"Storage of Liquids in Permanent Above Ground Tanks."
• Maintenance and repair of heavy equipment and vehicles involving oil changes,
hydraulic system drain down, solvent and de-greasing cleaning operations, fuel tank
drain down and removal, and other activities which may result in discharge or
spillage of pollutants to the ground or into stormwater runoff must be conducted
using spill prevention measures, such as drip pans. Contaminated surfaces shall be
cleaned immediately following any discharge or spill incident. Emergency repairs
may be performed on-site using temporary plastic placed beneath and, if raining, over
the vehicle.
• Wheel wash or tire bath wastewater shall be discharged to a separate on-site
treatment system or to the sanitary sewer, if available.
• Application of agricultural chemicals including fertilizers and pesticides shall be
conducted in a manner, and at application rates that will not result in loss of chemical
to stormwater runoff. Manufacturers' recommendations for application rates and
procedures shall be followed.
• See the BMP for Parking and Storage of Vehicles and Equipment in
Appendix C of this report.
See the Best Management Practices for this development that should be adhered to after
construction is complete.
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 13 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
10.0 PROJECT ENGINEER'S CERTIFICATION
I hereby state that this drainage plan for the Shearer Brothers Chipping, LLC. Industrial Property
has been prepared by me or under my supervision and meets the standard of care and expertise
which is usual and customary in this community for professional engineers.
Please contact Michael Staten at 360-275-9374 if you have any questions, comments, or require
additional information.
Sincerely,
Envirotech Engineering
CLYDE ST
WASy 9x
?o� 4SOO,
�SSIDNAL E'G`
Michael Staten,P.E.
Project Director
Envirotech Engineering Shearer Brothers Chipping,LLC Drainage Report
PO Box 984 page 14 100 NE Katchemak Lane
Belfair,Washington 98528 Mason County Parcel 12321-13-90051
360-275-9374 May 16,2012
•
APPENDIX A
SITE MAP
SCALE, 1 INCH = 100 FEET
0 25 50 100
3 r �
C-11
Q PROPERTY LINE
I
I
�e
�e
2e 305
J('
310
/ _
— x_
EXISTING 420' X x
V EATD SW_ } X _ X_ X
SEE DETAILS PROPOSED 556 SF ROOF
OVERFLOW PARKING. DOWNSPOUTINFILTRATION
SYSTEM.SEE DETAILS
�a DESIGNATED PARKING AREA At
FOR PROPOSED STORAGE /
WAREHOUSE.I HANDICAP,
STANDARD PARKING.
IV CLEARING LIMITS IS EXISTONG
h R»5 FENCE LINE
4 R•25' /
EXISTING 108'XH'X4'
VEGETATED PROPOSED
RETENTION FIRE TRUCK 120'X60' /
A TURNING He STORAGE I
WAREHOUSE ar +(
FF = 299.5 / 4
EXISTING RIPRAP ENERGY DISSIPATEXISTING./ TIVE
SURFACE PARKING 2`I q In
TP2
'./ DESIGNATED PARKING AREA I
FUR EXISTING MECHANIC SHOP x
I HANDICAP,7 STANDARD I A
PARKING.
/
EXISTING 25'X75'CONCRETE 3c
PAD WITH CENTERLINE SOP EXISTING
FOR SPILLCONTROL SLOPED SEPTIC /
TOVARD.S TREATMENT FACILITY / DRAIFELD
HC (opprx) /
/
EXtSTDMC GATE EXISTING I
y
MECHANIC SHOP FF-299 / EXISTING ROOF DOWNSPOUT TO
INFILTRATION(TYP)
EXISTING 5'MAX ECOLOGY
BLOCK(WALL(TYP) / �I
/ EXISTING ABOVE GROUND
LIQUID STORAGE TANKS TANKS
SHALL BE COVERED AND
MAINTAINED.SEE REPORT.
� I TOPOGRAPHY FROM PUBLIC
LIDAR, AND FIELD
MEASUREMENTS BY
390 FT * - / EXISTING ROADSIDE SWALE ENVIROTECH
EXISTING 31Y* —X —— X ——X — _
DIGRESS/EGRESS X—— —X _J
NE KA LAME
EXISTING co BASIN WITH
Dd/VATER SEPARATOR,
OBSERVATION PORT,AND SAND
TREATMENT(FILTRATION AREA
PROJECT/ OWNER/ LOCATION,
SHEARER DRAINAGE PLAN
SHEARER BROTHERS CHIPPING, LLC
100 NE KATCHEMAK LANE
PARCEL 12321-13-90051
MASON COUNTY WASHINGTON
ENGINEER-
ENVIROTECH ENGINEERING
P❑ BOX 984
BELFAIR, WASHINGTON 98528
360-275-9374
SITE MAP
APPENDIX B
HYDROLOGIC INFORMATION
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Table 2.2
Runoff Curve Numbers for Selected Agricultural, Suburban, and U an Areas
Sources:TR 55, 1986,and Stormwater Management Manual, 1992.See Section 2.1.1 r explanation)
CNs ydrologic soil group
Cover type and hydrologic condition. A B C D
Curve Numbers for Pre-Development Conditions
Pasture,grassland,or range-continuous forage for grazing:
Fair condition(ground cover 50a/a to 75%and not heavily grazed). 49 69 79 84
Good condition and cover>75%and lightly or only occasionally grazed) 39 61 74 80
Woods:
Fair(Woods are grazed but not burned,and some forest litter covers the soil). ® 60 73 79
Good Woods are protected from grazing,and litter and brush adequately cover the soil). 30 55 70 77
Curve Numbers for Post Develo meat Conditions
Open space(lawns,parks,golf courses,cemeteries,landscaping,etc.)
Fair condition(grass cover on 50%-75%of the area). (E) 85 90 92
Good condition cover on>75%of the area 68 80 86 90
Impervious areas:
Open water bodies:lakes,wetlands,ponds etc. 100 100 100 100
Paved parking lots,roofe,driveways,etc. (excluding right-of-way) OC> 98 98 98
Permeable Pavement(See Appendix C to decide which condition below to use)
Landscaped area 77 85 90 92
50%landscaped area/50%impervious 87 91 94 96
100%impervious area 98 98 98 98
Paved 98 98 98 98
Gravel(including right-of-way) 76 85 89 91
Dirt(including right-of-way) 72 82 87 89
Pasture,grassland,or range-continuous forage for grazing:
Poor condition(ground cover<50%or heavily grazed with no mulch). 68 79 86 89
Fair condition(ground cover 50a/o to 75%and not heavily grazed). 49 69 79 84
Good condition and cover>75%and lightly or only occasional) grazed) 39 61 74 80
Woods:
Poor(Forest litter,small trees,and brush are destroyed by heavy grazing or regular burning). 45 66 77 83
Fair(Woods are grazed but not burned,and some forest litter covers the soil). 36 60 73 79
Good(Woods are protected from grazing,and litter and brush adequately cover the soil). 30 55 70 77
Single family residential': Should only be used for Average Percent
Dwelling Unit/Gross Acre subdivisions>50 acres impervious areaa.4
1.0 DU/GA 15 Separate curve number
1.5 DU/GA 20 shall be selected for
2.0 DU/GA 25 pervious&impervious
2.5 DU/GA 30 portions of the site or
3.0 DU/GA 34 basin
3.5 DU/GA 38
4.0 DU/GA 42
4.5 DU/GA 46
5.0 DU/GA 48
5.5 DU/GA 50
6.0 DU/GA 52
6.5 DU/GA 54
7.0 DU/GA 56
7.5 DU/GA 58
PUD's,condos,apartments,commercial %impervious Separate curve numbers shall
businesses,industrial areas& must be be selected for pervious and
&subdivisions<50 acres computed impervious portions of the site
For a more detailed and complete description of land use curve numbers refer to chapter two(2)of the Soil Conservation Service's Technical
Release No.55, 210-VI-TR-55,Second Ed.,June 1986).
'Composite CN's may be computed for other combinations of open space cover type.
ZWhcre roof runoff and driveway runoff are infiltrated or dispersed according to the requirements in Chapter 3,the average percent impervious
area may be adjusted in accordance with the procedure described under"Flow Credit for Roof Downspout Infiltration"(Section 3.1.1),and"Flow
Credit for Roof Downspout Dispersion"(Section 3.11).
3Assumes roof and driveway runoff is directed into street/storm system.
4All the remaining pervious area(lawn)are considered to be in good condition for these curve numbers.
February 2005 Volume 1/1-Hydrologic Analysis and Flow Control BMPs 2-15
2.3.2 Runoff Parameters
All storm event hydrograph methods require input of parameters that
describe physical drainage basin characteristics. These parameters provide
the basis from which the runoff hydrograph is developed. This section
describes only the key parameter of curve number that is used to estimate the
runoff from the water quality design storm. .
Curve Number The NRCS (formerly SCS)has, for many years, conducted studies of the
runoff characteristics for various land types. After gathering and
analyzing extensive data,NRCS has developed relationships between land
use, soil type, vegetation cover, interception, infiltration, surface storage,
and runoff. The relationships have been characterized by a single runoff
coefficient called a"curve number." The National Engineering Handbook
- Section 4:Hydrology(NEH-4, SCS,August 1972) contains a detailed
description of the development and use of the curve number method.
NRCS has developed"curve number"(CN)values based on soil type and
land use. They can be found in"Urban Hydrology for Small Watersheds",
Technical Release 55 (TR-55),June 1986,published by the NRCS. The
combination of these two factors is called the"soil-cover complex." The
soil-cover complexes have been assigned to one of four hydrologic soil
groups, according to their runoff characteristics. NRCS has classified over
4,000 soil types into these four soil groups. Table 2.2 shows the
hydrologic soil group of most soils in the state of Washington and
provides a brief description of the four groups. For details on other soil
types refer to the NRCS publication mentioned above (TR-55, 1986).
Table 2.1 Hydrologic Soil Series for Selected Soils in Wash!n ton State
Soil Type Hydrologic Soil Group Soil Type Hydrologic Soil Group
Agnew C Hoko C
Ahl B Hoodsport C
Aits C Hoogdal C
Alderwood C Hoypus A
Arents,Alderwood B A
Arents,Everett B ZI. anolaAshoe B B
Baldhill B Jumpe B
Bameston C Kalaloch C
Baumgard B Kapowsin C/D
Beausite B Katula C
Belfast C Kilchis C
Bellingham D Kitsap C
Bellingham variant C Klaus C
Boistfort B Klone B
Bow D Lates C
Briscot D Lebam B
Buckley C Lummi D
Bunker B Lynnwood A
Cagey C Lystair B
Carlsborg A Mal C
Casey D Manley B
February 2005 Volume Ill—Hydrologic Analysis and Flow Control BMPs 2-11
Inflow Hydrograph
1 .20
1.00
-• 0.80
v
3 0.60
0
0.40
0.20
0.00 Looee! 1 4
0 5 10 15 20 25 30
Time (hr)
i
Outflow Hydrograph
0.30
0.25
0.20
c 0.15
E .Joe
0.10
0.05
0.00
0 5 10 15 20 25 30
Time (hr)
Single Event Hydrograph Method
input Swale Parameters
Design Storm 6mo-24hr w, bottom width (ft) 2.5
P, precipitation depth (in) 2.7 h, swale height(ft) 1.5
CN, pre-existing curve number 81 I, length of pond (ft) 420
CN, proposed curve number 98 run, horizontal component of side slope (ft) 3
rise, vertical component of side slope (ft) 1
Al, proposed area of change (sf) 67700 (must have consistent CN) slope (%) 1
A2, area left unchanged (so 0 (must have consistent CN) slope(deg) 0.6
L1, flow length (ft) 266
L2, flow length (ft) 0 trapezoidal 3:1 swale while in flow
s1, slope (ft/ft) 0.02 Q, peak flow(cfs) 1.1
s2, slope (ft/ft) 0 h, water height(ft) 0.33
R, hydraulic radius 0.1 Area required (sf) 0.27
n, Manning's roughness coeff. 0.011 Bottom width (ft) -0.18
f, infiltration rate (in/hr) 2
d, subsurface distance (ft) 3
output
SCS Curve Number Equations
S= 2.35 Max. natural detention due to infiltration, storage, etc. Pre-Existing (in) S=1000/CN-10
S= 0.20 Max. natural detention due to infiltration, storage, etc. Proposed (in)
Qd = 2.47 Runoff depth over area (in)
V= 11874.89 Runoff volume(cubic feet)
k= 29.16 time of concentration velocity factor(ft/sec) k=(1.49*R^0.667)/n
v1= 4.12 velocity of flow(ft/sec) v=k*SQRT(s)
v2= 0.00 velocity of flow(ft/sec)
Tt1= 1.07 Travel time (min) Tt=L/(60*v)
Tt2= 0.00 Travel time (min)
Tc= 1.07 Time of concentration (min) Tc=Tt1+Tt2+....Ttm
w= 0.82 routing constant w=dt/(2Tc+dt)
Santa Barbara Urban H dro ra h Method Add Snowmelt Factor to h eto raph if elevation is above 1000 feet
Existing Conditions Proposed Conditions Total
Time Type IA Rainfall Incre. Rain accu. Rain Accum. Incre. Tot. Runoff It Des. Flow Accum, Incre. Tot. Runoff It Des. Flow Des. Flow
hr Distribution (dec.) (in) (in) Runoff(in)Runoff(in) (in) cfs) Rate (cfs) Runoff(in)Runoff(in) (in) (cfs) Rate cfs) Rate cfs
0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.2 0.004 0.011 0.011 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.3 0.004 0.011 0.022 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.5 0.004 0.011 0.032 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.7 0.004 0.011 0.043 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.8 0.004 0.011 0.054 0.000 0.000 0.000 0.000 0.000 0.001 0.001 0.001 0.006 0.005 0.005
1.0 0.004 0.011 0.065 0.000 0.000 0.000 0.000 0.000 0.003 0.002 0.002 0.014 0.013 0.013
1.2 0.004 0.011 0.076 0.000 0.000 0.000 0.000 0.000 0.005 0.003 0.003 0.020 0.020 0.020
1.3 0.004 0.011 0.086 0.000 0.000 0.000 0.000 0.000 0.008 0.003 0.003 0.026 0.026 0.026
1.5 0.004 0.011 0.097 0.000 0.000 0.000 0.000 0.000 0.012 0.004 0.004 0.031 0.031 0.031
1.7 0.004 0.011 0.108 0.000 0.000 0.000 0.000 0.000 0.017 0.004 0.004 0.036 0.035 0.035
1.8 0.005 0.014 0.122 0.000 0.000 0.000 0.000 0.000 0.023 0.006 0.006 0.050 0.048 0.048
2.0 0.005 0.014 0.135 0.000 0.000 0.000 0.000 0.000 0.030 0.007 0.007 0.055 0.056 0.056
2.2 0.005 0.014 0.149 0.000 0.000 0.000 0.000 0.000 0.037 0.007 0.007 0.060 0.059 0.059
2.3 0.005 0.014 0.162 0.000 0.000 0.000 0.000 0.000 0.045 0.008 0.008 0.064 0.064 0.064
2.5 0.005 0.014 0.176 0.000 0.000 0.000 0.000 0.000 0.054 0.008 0.008 0.067 0.067 0.067
2.7 0.005 0.014 0.189 0.000 0.000 0.000 0.000 0.000 0.062 0.009 0.009 0.070 0.070 0.070
2.8 0.006 0.016 0.205 0.000 0.000 0.000 0.000 0.000 0.073 0.011 0.011 0.088 0.085 0.085
3.0 0.006 0.016 0.221 0.000 0.000 0.000 0.000 0.000 0.085 0.011 0.011 0.092 0.093 0.093
3.2 0.006 0.016 0.238 0.000 0.000 0.000 0.000 0.000 0.097 0.012 0.012 0.095 0.093 0.093
3.3 0.006 0.016 0.254 0.000 0.000 0.000 0.000 0.000 0.109 0.012 0.012 0.097 0.098 0.098
3.5 0.006 0.016 0.270 0.000 0.000 0.000 0.000 0.000 0.121 0.012 0.012 0.100 0.099 0.099
3.7 0.006 0.016 0.286 0.000 0.000 0.000 0.000 0.000 0.134 0.013 0.013 0.102 0.102 0.102
3.8 0.007 0.019 0.305 0.000 0.000 0.000 0.000 0.000 0.149 0.015 0.015 0.121 0.118 0.118
4.0 0.007 0.019 0.324 0.000 0.000 0.000 0.000 0.000 0.165 0.015 0.015 0.124 0.126 0.126
4.2 0.007 0.019 0.343 0.000 0.000 0.000 0.000 0.000 0.180 0.016 0.016 0.126 0.124 0.124
4.3 0.007 0.019 0.362 0.000 0.000 0.000 0.000 0.000 0.196 0.016 0.016 0.128 0.128 0.128
4.5 0.007 0.019 0.381 0.000 0.000 0.000 0.000 0.000 0.212 0.016 0.016 0.129 0.129 0.129
4.7 0.007 0.019 0.400 0.000 0.000 0.000 0.000 0.000 0.229 0.016 0.016 0.131 0.131 0.131
4.8 0.008 0.022 0.422 0.000 0.000 0.000 0.000 0.000 0.248 0.019 0.019 0.155 0.151 0.151
5.0 0.008 0.022 0.444 0.000 0.000 0.000 0.000 0.000 0.268 0.020 0.020 0.157 0.159 0.159
5.2 0.008 0.022 0.466 0.000 0.000 0.000 0.000 0.000 0.287 0.020 0.020 0.158 0.156 0.156
5.3 0.008 0.022 0.488 0.000 0.000 0.000 0.000 0.000 0.307 0.020 0.020 0.159 0.160 0.160
5.5 0.008 0.022 0.510 0.001 0.001 0.001 0.000 0.000 0.327 0.020 0.020 0.161 0.160 0.160
5.7 0.008 0.022 0.532 0.002 0.001 0.001 0.000 0.000 0.347 0.020 0.020 0.162 0.162 0.162
5.8 0.010 0.026 0.558 0.003 0.002 0.002 0.000 0.000 0.371 0.024 0.024 0.188 0.184 0.184
6.0 0.010 0.026 0.584 0.005 0.002 0.002 0.000 0.000 0.395 0.024 0.024 0.190 0.193 0.193
6.2 0.010 0.026 0.609 0.008 0.003 0.003 0.000 0.000 0.418 0.024 0.024 0.191 0.189 0.189
6.3 0.010 0.026 0.635 0.011 0.003 0.003 0.000 0.000 0.442 0.024 0.024 0.192 0.193 0.193
6.5 0.010 0.026 0.661 0.014 0.004 0.004 0.000 0.000 0.466 0.024 0.024 0.193 0.192 0.192
6.7 0.010 0.026 0.686 0.018 0.004 0.004 0.000 0.000 0.490 0.024 0.024 0.193 0.194 0.194
6.8 0.013 0.036 0.723 0.025 0.006 0.006 0.000 0.000 0.525 0.034 0.034 0.274 0.259 0.259
7.0 0.013 0.036 0.759 0.032 0.007 0.007 0.000 0.000 0.559 0.034 0.034 0.275 0.284 0.284
7.2 0.013 0.036 0.795 0.040 0.008 0.008 0.000 0.000 0.593 0.034 0.034 0.276 0.270 0.270
7.3 0.018 0.049 0.843 0.052 0.012 0.012 0.000 0.000 0.640 0.047 0.047 0.373 0.360 0.360
7.5 0.018 0.049 0.892 0.065 0.013 0.013 0.000 0.000 0.687 0.047 0.047 0.374 0.382 0.382
7.7 0.034 0.092 0.984 0.093 0.028 0.028 0.000 0.000 0.775 0.089 0.089 0.710 0.646 0.646
7.8 0.054 0.146 1.130 0.145 0.053 0.053 0.000 0.000 0.917 0.142 0.142 1.136 1.102 1.102
8.0 0.027 0.073 1.203 0.175 0.030 0.030 0.000 0.000 0.988 0.071 0.071 0.570 0.692 0.692
8.2 0.018 0.049 1.251 0.196 0.021 0.021 0.000 0.000 1.036 0.048 0.048 0.381 0.336 0.336
8.3 0.013 0.036 1.287 0.212 0.016 0.016 0.000 0.000 1.071 0.035 0.035 0.284 0.330 0.330
8.5 0.013 0.036 1.324 0.228 0.017 0.017 0.000 0.000 1.107 0.035 0.035 0.284 0.254 0.254
8.7 0.013 0.036 1.360 0.245 0.017 0.017 0.000 0.000 1.142 0.036 0.036 0.285 0.304 0.304
8.8 0.009 0.024 1.383 0.256 0.011 0.011 0.000 0.000 1.166 0.023 0.023 0.187 0.192 0.192
9.0 0.009 0.024 1.407 0.268 0.012 0.012 0.000 0.000 1.189 0.023 0.023 0.187 0.184 0.184
9.2 0.009 0.024 1.431 0.280 0.012 0.012 0.000 0.000 1.212 0.023 0.023 0.187 0.189 0.189
9.3 0.009 0.024 1.455 0.292 0.012 0.012 0.000 0.000 1.236 0.023 0.023 0.187 0.186 0.186
9.5 0.009 0.024 1.479 0.304 0.012 0.012 0.000 0.000 1.259 0.023 0.023 0.187 0.188 0.188
9.7 0.009 0.024 1.502 0.316 0.012 0.012 0.000 0.000 1.282 0.023 0.023 0.188 0.187 0.187
9.8 0.009 0.024 1.526 0.328 0.012 0.012 0.000 0.000 1.306 0.023 0.023 0.188 0.188 0.188
10.0 0.009 0.024 1.550 0.341 0.013 0.013 0.000 0.000 1.329 0.023 0.023 0.188 0.187 0.187
10.2 0.009 0.024 1.574 0,354 0.013 0.013 0.000 0.000 1.353 0.023 0.023 0.188 0.188 0.188
10.3 0.009 0.024 1.597 0.366 0.013 0.013 0.000 0.000 1.376 0.023 0.023 0.188 0.188 0.188
10.5 0.009 0.024 1.621 0.379 0.013 0.013 0.000 0.000 1.400 0.023 0.023 0.188 0.188 0.188
10.7 0.009 0.024 1.645 0.393 0.013 0.013 0.000 0.000 1.423 0.023 0.023 0.188 0.188 0.188
10.8 0.007 0.019 1.664 0.403 0.011 0.011 0.000 0.000 1.442 0.019 0.019 0.154 0.160 0.160
11.0 0.007 0.019 1.684 0.414 0.011 0.011 0.000 0.000 1.461 0.019 0.019 0.154 0.150 0.150
r
APPENDIX C
BEST MANAGEMENT PRACTICES
(BMP'S)
l
BMPs for Description of Pollutant Sources: Above-ground tanks containing
Storage of liquids (excluding uncontaminated water)may be equipped with a valved
Liquids in drain,vent,pump, and bottom hose connection. They may be heated with
Permanent steam heat exchangers equipped with steam traps. Leaks and spills can
Above-ground occur at connections and during liquid transfer. Oil and grease, organics,
Tanks acids, alkalis, and heavy metals in tank water and condensate drainage can
also cause stormwater contamination at storage tanks.
Pollutant Control Approach: Install secondary containment or a double-
walled tank. Slope the containment area to a drain with a sump.
Stormwater collected in the containment area may need to be discharged
to treatment such as an API or CP oil/water separator, or equivalent BMP.
Add safeguards against accidental releases including protective guards
around tanks to protect against vehicle or forklift damage, and tagging
valves to reduce human error. Tank water and condensate discharges are
process wastewater that may need an NPDES Permit.
Applicable Operational BMPs:
• Inspect the tank containment areas regularly to identify problem
components such as fittings, pipe connections, and valves, for
leaks/spills, cracks, corrosion, etc.
• Place adequately sized drip pans beneath all mounted taps and
drip/spill locations during filling/unloading of tanks. Valved drain
tubing may be needed in mounted drip pans.
• Sweep and clean the tank storage area regularly, if paved.
• Replace or repair tanks that are leaking, corroded, or otherwise
deteriorating.
• All installations shall comply with the Uniform Fire Code (Appendix
IV-D R.2) and the National Electric Code.
Applicable Structural Source Control BMPs:
• Locate permanent tanks in impervious (Portland cement concrete or
equivalent) secondary containment surrounded by dikes as illustrated
in Figure 2.12, or UL Approved double-walled. The dike must be of
sufficient height to provide a containment volume of either 10 percent
of the total enclosed tank volume or 110 percent of the volume
contained in the largest tank, whichever is greater, or, if a single tank,
110 percent of the volume of that tank.
• Slope the secondary containment to drain to a dead-end sump
(optional), or equivalent, for the collection of small spills.
• Include a tank overfill protection system to minimize the risk of
spillage during loading.
2-58 Volume IV-Source Control BMPs February 2005
tt
Figure 2.12—Above-ground Tank Storage
Applicable Treatment BMPs:
• If the tank containment area is uncovered, equip the outlet from the
Note the spill-containment sump with a shutoff valve,which is normally closed
applicable and may be opened,manually or automatically, only to convey
treatment BMP contaminated stormwater to approved treatment or disposal,or to
for stormwater convey uncontaminated stormwater to a storm drain. Evidence of
from petroleum contamination can include the presence of visible sheen,color,or
tank farms. turbidity in the runoff,or existing or historical operational problems at
the facility. Simple pH measurements with litmus or pH paper can be
used for areas subject to acid or alkaline contamination.
• At petroleum tank farms, convey stormwater contaminated with
floating oil or debris in the contained area through an API or CP-type
oil/water separator(Volume V, Treatment BMPs), or other approved
treatment prior to discharge to storm drain or surface water.
February 2005 Volume IV- Source Control BMPs 2-59
Y'
BMPs for Spills Description of Pollutant Sources: Owners or operators of facilities
of O i I and engaged in drilling,producing, gathering, storing,processing,transferring,
Hazardous distributing,refining or consuming oil and/or oil products are required by
Substances Federal Law to have a Spill Prevention and Control Plan if the storage
capacity of the facility,which is not buried, is 1,320 gallons or more of oil,
or any single container with a capacity in excess of 660 gallons and which,
due to their location,could reasonably be expected to discharge oil in
harmful quantities,as defined in 40 CFR Part 110, into or upon the
navigable waters of the United States or adjoining shorelines (40 CFR
112.1 (b)}. Onshore and offshore facilities,which,due to their location,
could not reasonably be expected to discharge oil into or upon the
navigable waters of the United States or adjoining shorelines are exempt
from these regulations 140 CFR 112.1(1)(i)). Owners of businesses that
produce Dangerous Wastes are also required by State Law to have a spill
control plan. These businesses should refer to Appendix IV-D R.6. The
federal definition of oil is oil of any kind or any form, including,but not
limited to petroleum, fuel oil, sludge, oil refuse, and oil mixed with wastes
other than dredged spoil.
Pollutant Control Approach: Maintain,update, and implement an oil
spill prevention/cleanup plan.
Applicable Operational BMPs: The businesses and public agencies
identified in Appendix IV-A that are required to prepare and implement an
Emergency Spill Cleanup Plan shall implement the following:
• Prepare an Emergency Spill Control Plan(SCP),which includes:
- A description of the facility including the owner's name and
address;
- The nature of the activity at the facility;
- The general types of chemicals used or stored at the facility;
- A site plan showing the location of storage areas for chemicals, the
locations of storm drains,the areas draining to them, and the
location and description of any devices to stop spills from leaving
the site such as positive control valves;
- Cleanup procedures;
- Notification procedures to be used in the event of a spill, such as
notifying key personnel. Agencies such as Ecology, local fire
department,Washington State Patrol, and the local Sewer
Authority, shall be notified;
- The name of the designated person with overall spill cleanup and
notification responsibility;
February 2005 Volume IV- Source Control BMPs 2-53
I�
• Train key personnel in the implementation of the Emergency SCP.
Prepare a summary of the plan and post it at appropriate points in the
building,identifying the spill cleanup coordinators, location of cleanup
kits, and phone numbers of regulatory agencies to be contacted in the
event of a spill;
• Update the SCP regularly;
• Immediately notify Ecology and the local Sewer Authority if a spill
may reach sanitary or storm sewers, ground water, or surface water, in
accordance with federal and Ecology spill reporting requirements;
• Immediately clean up spills. Do not use emulsifiers for cleanup unless
an appropriate disposal method for the resulting oily wastewater is
implemented. Absorbent material shall not be washed down a floor
drain or storm sewer; and,
• Locate emergency spill containment and cleanup kit(s)in high
potential spill areas. The contents of the kit shall be appropriate for
the type and quantities of chemical liquids stored at the facility.
Recommended Additional Operational BMP: Spill kits should include
appropriately lined drums,absorbent pads, and granular or powdered
materials for neutralizing acids or alkaline liquids where applicable. In
fueling areas: absorbent should be packaged in small bags for easy use and
small drums should be available for storage of absorbent and/or used
absorbent. Spill kits should be deployed in a manner that allows rapid
access and use by employees.
2-54 Volume IV- Source Control BMPs February 2005
1
BMPs for Description of Pollutant Sources: Public and commercial parking lots
Parking and such as retail store, fleet vehicle(including rent-a-car lots and car
Storage of dealerships),equipment sale and rental parking lots, and parking lot
Vehicles and driveways, can be sources of toxic hydrocarbons and other organic
Equipment compounds,oils and greases,metals, and suspended solids caused by the
parked vehicles.
Pollutant Control Approach: If the parking lot is a high-use site as
defined below,provide appropriate oil removal equipment for the
contaminated stormwater runoff.
Applicable Operational BMPs:
• If washing of a parking lot is conducted,discharge the washwater to a
sanitary sewer,if allowed by the local sewer authority, or other
approved wastewater treatment system, or collect it for off-site
disposal.
• Do not hose down the area to a storm drain or to a receiving water.
Sweep parking lots, storage areas, and driveways,regularly to collect
dirt,waste,and debris.
Applicable Treatment BMPs: An oil removal system such as an API or
CP oil and water separator, catch basin filter, or equivalent BMP,
approved by the local jurisdiction, is applicable for parking lots meeting
the threshold vehicle traffic intensity level of a high-use site.
Vehicle High-Use Sites
Establishments subject to a vehicle high-use intensity have been
determined to be significant sources of oil contamination of stormwater.
Examples of potential high use areas include customer parking lots at fast
food stores,grocery stores,taverns,restaurants, large shopping malls,
discount warehouse stores,quick-lube shops, and banks. If the PGIS for a
high-use site exceeds 5,000 square feet in a threshold discharge area, and
oil control BMP from the Oil Control Menu is necessary. A high-use site
at a commercial or industrial establishment has one of the following
characteristics: (Gaus/King County, 1994)
• Is subject to an expected average daily vehicle traffic (ADT)count
equal to or greater than 100 vehicles per 1,000 square feet of gross
building area: or
• Is subject to storage of a fleet of 25 or more diesel vehicles that are
over 10 tons gross weight(trucks,buses,trains,heavy equipment,
etc.).
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BMPs for Description of Pollutant Sources: Pollutant sources include parts/vehicle
Maintenance and cleaning,spills/leaks of fuel and other liquids,replacement of liquids,
Repair of outdoor storage of batteries/liquids/parts,and vehicle parking.
Vehicles and
Equipment Pollutant Control Approach: Control of leaks and spills of fluids using
good housekeeping and cover and containment BMPs.
Applicable Operational BMPs:
• Inspect for leaks all incoming vehicles,parts,and equipment stored
temporarily outside.
• Use drip pans or containers under parts or vehicles that drip or that are
likely to drip liquids, such as during dismantling of liquid containing
parts or removal or transfer of liquids.
• Remove batteries and liquids from vehicles and equipment in
designated areas designed to prevent stormwater contamination. Store
cracked batteries in a covered non-leaking secondary containment
system.
• Empty oil and fuel filters before disposal. Provide for proper disposal
of waste oil and fuel.
• Do not pour/convey washwater, liquid waste, or other pollutant into
storm drains or to surface water. Check with the local sanitary sewer
authority for approval to convey to a sanitary sewer.
• Do not connect maintenance and repair shop floor drains to storm
drains or to surface water. To allow for snowmelt during the winter a
drainage trench with a sump for particulate collection can be installed
and used only for draining the snowmelt and not for discharging any
vehicular or shop pollutants.
Applicable Structural Source Control BMPs:
• Conduct all maintenance and repair of vehicles and equipment in a
building, or other covered impervious containment area that is sloped
to prevent run-on of uncontaminated stormwater and runoff of
contaminated stormwater.
• The maintenance of refrigeration engines in refrigerated trailers may
be conducted in the parking area with due caution to avoid the release
of engine or refrigeration fluids to storm drains or surface water.
• Park large mobile equipment, such as log stackers,in a designated
contained area.
For additional applicable BMPs refer to the following BMPs: Fueling at
Dedicated Stations;Washing and Steam Cleaning
Vehicle/Equipment/Building Structures; Loading and Unloading Areas for
Liquid or Solid Material; Storage of Liquids in Permanent Above-Ground
Tanks; Storage of Liquid, Food Waste, or Dangerous Waste Containers;
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Storage or Transfer(Outside)of Solid Raw Materials,By-Products, or
Finished Products; Spills of Oil and Hazardous Substances;Illicit
Connections to Storm Drains; and other BMPs provided in this chapter.
Applicable Treatment BWs: Contaminated stormwater runoff from
Note that a vehicle staging and maintenance areas must be conveyed to a sanitary
treatment BMP is sewer, if allowed by the local sewer authority, or to an API or CP oil and
applicable for water separator followed by a basic treatment BMP(See Volume V)
contaminated applicable filter, or other equivalent oil treatment system.
stormwater. i
Recommended Additional Operational BMPs:
• Consider storing damaged vehicles inside a building or other covered
containment,until all liquids are removed. Remove liquids from
vehicles retired for scrap.
• Clean parts with aqueous detergent based solutions or non-chlorinated
solvents such as kerosene or high flash mineral spirits, and/or use wire
brushing or sand blasting whenever practicable. Avoid using tonic
liquid cleaners such as methylene chloride, 1,1,1-trichloroethane,
trichloroethylene or similar chlorinated solvents. Choose cleaning
agents that can be recycled.
• Inspect all BMPs regularly,particularly after a significant storm.
Identify and correct deficiencies to ensure that the BMPs are
functioning as intended.
• Avoid hosing down work areas. Use dry methods for cleaning leaked
fluids.
• Recycle greases,used oil, oil filters, antifreeze, cleaning solutions,
automotive batteries,hydraulic fluids,transmission fluids, and engine
oils (see Appendix IV-Q.
• Do not mix dissimilar or incompatible waste liquids stored for
recycling.
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BMPs for Description of Pollutant Sources: Loading/unloading of liquid and solid
Loading and materials at industrial and commercial facilities are typically conducted at
Unloading Areas shipping and receiving, outside storage, fueling areas, etc. Materials
for Liquid or transferred can include products, raw materials, intermediate products,
Solid Material waste materials, fuels, scrap metals, etc. Leaks and spills of fuels, oils,
powders, organics, heavy metals, salts, acids, alkalis, etc. during transfer
are potential causes of stormwater contamination. Spills from hydraulic
line breaks are a common problem at loading docks.
Pollutant Control Approach: Cover and contain the loading/unloading
area where necessary to prevent run-on of stormwater and runoff of
contaminated stormwater.
Applicable Operational BMPs:
At All Loading/Unloading Areas:
• A significant amount of debris can accumulate at outside,uncovered
loading/unloading areas. Sweep these surfaces frequently to remove
material that could otherwise be washed off by stormwater. Sweep
outside areas that are covered for a period of time by containers, logs,
or other material after the areas are cleared.
• Place drip pans, or other appropriate temporary containment device, at
locations where leaks or spills may occur such as hose connections,
hose reels and filler nozzles. Drip pans shall always be used when
making and breaking connections (see Figure 2.2). Check loading/
unloading equipment such as valves, pumps, flanges, and connections
regularly for leaks and repair as needed.
Drip pan
Figure 2.2—Drip Pan
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At Tanker Truck and Rail Transfer Areas to AboveBelow ground
Storage Tanks:
• To minimize the risk of accidental spillage, prepare an "Operations
Plan" that describes procedures for loading/unloading. Train the
employees, especially fork lift operators, in its execution and post it or
otherwise have it readily available to employees.
• Report spills of reportable quantities to Ecology (refer to Section 2.1
for telephone numbers of Ecology Regional Offices).
• Prepare and implement an Emergency Spill Cleanup Plan for the
facility (BMP Spills of Oil and Hazardous Substances) which includes
the following BMPs:
- Ensure the clean up of liquid/solid spills in the loading/unloading
area immediately, if a significant spill occurs, and,upon
completion of the loading/unloading activity, or, at the end of the
working day.
- Retain and maintain an appropriate oil spill cleanup kit on-site for
rapid cleanup of material spills. (See BMP Spills of Oil and
Hazardous Substances).
- Ensure that an employee trained in spill containment and cleanup
is present during loading/unloading.
At Rail Transfer Areas to Above/below-ground Storage Tanks:Install a
drip pan system as illustrated(see Figure 2.3)within the rails to collect
spills/leaks from tank cars and hose connections, hose reels, and filler
nozzles.
Drip pan within rails
Figure 2.3-Drip Pan Within Rails
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Loading/Unloading fromfto Marine Vessels:Facilities and procedures for
the loading or unloading of petroleum products must comply with Coast
Guard requirements specified in Appendix IV-D R.5.
Transfer of Small Quantities from Tanks and Containers:Refer to
BMPs Storage of Liquids in Permanent Above-Ground Tanks, and Storage
of Liquid, Food Waste, or Dangerous Waste Containers,for requirements
on the transfer of small quantities from tanks and containers,respectively.
Applicable Structural Source Control BWs:
At All Loading/Unloading Areas:
• Consistent with Uniform Fire Code requirements(Appendix IV-D
R.2) and to the extent practicable,conduct unloading or loading of
solids and liquids in a manufacturing building,under a roof, or lean-to,
or other appropriate cover.
• Berm, dike, and/or slope the loading/unloading area to prevent run-on
of stormwater and to prevent the runoff or loss of any spilled material
from the area.
• Large loading areas frequently are not curbed along the shoreline. As
a result,stormwater passes directly off the paved surface into surface
water. Place curbs along the edge,or slope the edge such that the
stormwater can flow to an internal storm drain system that leads to an
approved treatment BMP.
• Pave and slope loading/unloading areas to prevent the pooling of
water. The use of catch basins and drain lines within the interior of the
paved area must be minimized as they will frequently be covered by
material, or they should be placed in designated"alleyways"that are
not covered by material, containers or equipment.
Recommended Structural Source Control BMP: For the transfer of
pollutant liquids in areas that cannot contain a catastrophic spill, install an
automatic shutoff system in case of unanticipated off-loading interruption
(e.g. coupling break,hose rupture, overfill, etc.).
At Loading and Unloading Docks:
• Install/maintain overhangs, or door skirts that enclose the trailer end
(see Figures 2.4 and 2.5)to prevent contact with rainwater.
• Design the loading/unloading area with berms, sloping, etc. to prevent
the run-on of stormwater.
• Retain on-site the necessary materials for rapid cleanup of spills.
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Figure 2.4—Loading Dock with Door Skirt
Figure 2.5—Loading Dock with Overhang
At Tanker Truck Transfer Areas to AboveBelow-Ground Storage
Tanks:
• Pave the area on which the transfer takes place. If any transferred
liquid, such as gasoline, is reactive with asphalt pave the area with
Portland cement concrete.
• Slope, berm, or dike the transfer area to a dead-end sump, spill
containment sump, a spill control (SQ oil/water separator, or other
spill control device. The minimum spill retention time should be 15
minutes at the greater flow rate of the highest fuel dispenser nozzle
through-put rate, or the peak flow rate of the 6-month, 24-hour storm
event over the surface of the containment pad, whichever is greater.
The volume of the spill containment sump should be a minimum of 50
gallons with an adequate grit sedimentation volume.
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BMPs for Dust Description of Pollutant Sources: Dust can cause air and water pollution
Control at problems particularly at demolition sites and in and areas where reduced
Disturbed Land rainfall exposes soil particles to transport by air.
Areas and
Unpaved Pollutant Control Approach: Minimize dust generation and apply
Roadways and environmentally friendly and government approved dust suppressant
Parking Lots chemicals, if necessary.
Applicable Operational BMPs:
• Sprinkle or wet down soil or dust with water as long as it does not
result in a wastewater discharge.
• Use only local and/or state government approved dust suppressant
chemicals such as those listed in Ecology Publication#96-433,
"Techniques for Dust Prevention and Suppression."
• Avoid excessive and repeated applications of dust suppressant
chemicals. Time the application of dust suppressants to avoid or
minimize their wash-off by rainfall or human activity such as
irrigation.
• Apply stormwater containment to prevent the conveyance of
stormwater TSS into storm drains or receiving waters.
• The use of motor oil for dust control is prohibited. Care should be
taken when using lignin derivatives and other high BOD chemicals in
excavations or areas easily accessible to surface water or ground
water.
• Consult with the Ecology Regional Office in your area on discharge
permit requirements if the dust suppression process results in a
wastewater discharge to the ground, ground water, storm drain, or
surface water.
Recommended Additional Operational BMPs for Roadways and
Other Trafficked Areas:
• Consider limiting use of off-road recreational vehicles on dust
generating land.
• Consider paving unpaved permanent roads and other trafficked areas
at municipal, commercial, and industrial areas.
• Consider paving or stabilizing shoulders of paved roads with gravel,
vegetation, or local government approved chemicals.
• Encourage use of alternate paved routes, if available.
• Vacuum or wet sweep fine dirt and skid control materials from paved
roads soon after winter weather ends or when needed.
• Consider using traction sand that is pre-washed to reduce dust
emissions.
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Additional Recommended Operational BMPs for Dust Generating
Areas:
• Prepare a dust control plan. Helpful references include: Control of
Open Fugitive Dust Sources (EPA-450/3-88-088), and Fugitive Dust
Background Document and Technical Information Document for Best
Available Control Measures (EPA450/2-92-004)
• Limit exposure of soil (dust source) as much as feasible.
• Stabilize dust-generating soil by growing and maintaining vegetation,
mulching, topsoiling, and/or applying stone, sand, or gravel.
• Apply windbreaks in the soil such as trees, board fences, tarp curtains,
bales of hay, etc.
• Cover dust-generating piles with wind-impervious fabric, or equivalent
material.
February 2005 Volume IV-Source Control BMPs 2-17
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