HomeMy WebLinkAboutPermit File BLD-2020-0572 607 R Avenue (8)N FILE COPY
G1T x C SEP 2 2 202(
Storm Water Drainage Report
_ tTY OF - `FC_ WF'�!Winimum Requirements 1 through 5
Minimum Requirement 1 through 9
co�`�' ENGINEERING DEPARTMENT
904 6t" Street Anacortes, WA 98221
www.anacorteswa.gov.
Official Use Only: (Information
Required Storm Water Facility
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to Inspectors)
and other related requirements:
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Project Address: lrnnl 7 Aw r At6}i=& 98274
Parcel Number: P130 9
Permit Number: IGLM — p — D572
Submittal Date:
9 ^�Z"mod
Revision Number: Acz�ma+ sa°
Reviewer: 7riK As ��"�•
Acceptance Date (COA): 9 wZ3 -2*0 "�
FRONT OF REPORT:
Submittal Checklist: (All items listed below are required for a complete submittal)
Cover Sheet (Preparer to Provide): Project title, Location, Revision dates, Engineer's Stamp
�a i �..�;;e TAB 1: Minimum Requirement #1 — Preparation of Stormwater Site Plans
>, I� TAB 2: Minimum Requirement #2 — Construction Stormwater Pollution Prevention (SWPP)
o TAB 3: Minimum Requirement #3 — Source Control of Pollution
Jo TAB 4: Minimum Requirement #4 — Preservation of Natural Drainage Systems and Outfalls
jt lo TAB 5: Minimum Requirement #5 — On -site Stormwater Managements
o TAB 6: Minimum Requirement #6 — Runoff Treatment
o TAB 7: Minimum Requirement #7 — Flow Control
o TAB 8: Minimum Requirement #8 — Wetland Protection
TAB 9: Minimum Requirement #9 — Operation and Maintenance
�l APPENDIX 1 - Survey performed by a Professional Land Surveyor
APPENDIX 2 - Soils Analysis (Volume 1, Chapter 3.1.1)
APPENDIX 3 - Model Soil Management Plan for BMP T5.13
APPENDIX 4 - Determining Construction Site Sediment Damage Potential (Appendix 7)
APPENDIX 5 - Site Plan with all applicable information (Minimum Size 11x17 — 30 scale)
APPENDIX 6 - Documented Site Photos (North, South, East and West)
o APPENDIX 7 - Drainage BMP Facility Maintenance Covenant, if applicable. To be recorded prior to the
Temporary Certificate of Occupancy, Certificate of Occupancy or Final Acceptance,
Stormwater Management Requirements:
o Refer to the 201 2\1 4 Department of Ecology Manual, as amended in 2014 for further required
information.
o See also, City of Anacortes Municipal Code 19.76 for additional information
o See also, current Engineering Development Standards, Chapter 2- Storm Drainage for additional
information.
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
i
Project Description and Summary:
Summary Table
Existing
Proposed
Development Type
'PLA 7ZE2;;�n2()c)rY�i
Number of Lots
AIJF4
- Lot Acreage in SF i
,' 35 S7
Soil Type(s)
Site Sediment Transport Score Hi h ow •
►- r Q�r y l ►,Y,D'y L� nvr�
— H0 —
Depth to Ground Water Table (Feet an ches)
See completed Soils Analysis (Volume 1, Chapter 3.1.1
1 Q- 3�" �s 24 - 7Z"
Infiltration Rate duringRain Season (Inch\Per Hour)
J 4f6 O• off, � n /(�5 a i.Fsyb .g#5 "'
Impervious Surface (on -site)
332 �n�
Impervious Surface
(off —site),-
New and Replaced Hard Surface Total (SF)
WSf 6,4�4 SF EP4= /,3325F
Lot Coverage (Percentage)
�{$. `'0
BMP (Required Minimum Requirement 5)
BMP T5.13 Post Construction Soils N�'^
Pt
Water Quality Method (Minimum Re uirement 6)
11
Water Quantity Method (Minimum Requirement 7)
1 lU A
Existing Site Conditioitis Summary:
(Additionally, provide information on previous permits, if any, like Grade and Fill, Clear and Grade, topography,
vegetation, drainage, Critical Areas adjacent to the site and how it may affect this project if soils are disturbed,
Soils Type (Included in Soils Analysis Report), Erosion Problem Areas, Construction Phasing\Sequence )
Developed Conditions Summary;
(Additionally, to be shown on the site plan. Identify cut and fill areas, proposed slopes of all hard
surfaces, proposed contours)
Drainage Basin (2007 Storm Com Plan -City website\publicworks\engineering\comprehensive plans}:
What Drainage Basin are you in? � Identify any downstream drainage issues (Storm Comp Plan:
If on rinerrihnV
Complete the Applicability Requirements —Flow Chart (Figure I-2.4.1 Attached, Figure I-2.4.2 Attached
and Figure I-2.5.1 Attached)
- Highlight the path and attach
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
start Here
Dads the srte �avE3C°fi
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al ply to Ow new and replaced
hard surfaces and converted
vegetation" areas.
DEPARTMENT OF
EC®LOGY
Slate of WasRington
des
es See Redevelopment Minimum
Requi rements and Flow Chart
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Minirrtum Requirements �#
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eyed replaced hard surfaces
and the land disturbed.
C�-s the �r�1=ct resin: in �.CC�C
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repla ec nerd surface area?
Does :rL is ,jeect have land
dis:urtfi aCE1,419es 0; 70000
es Su il3 �= `CW ?a Gr greaterry
�4
Minimum Requirement t�2
applies_
Figure I-2.4.1
Flow Chart for Determining Requirements for
New
Development
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TAB 1 (MINIMUM REQUIREMENT #1)
�l 8 1 .
• 1-2.5.1 Minimum Requirement #1 — Prepare a Stormwater Site Plan
1.3 — Preparation of a Stormwater Site Plan
- 1.3.1 — Stormwater Site Plans: Step -by -Step
Note: The level of detail needed for each step depends upon the project size. Provide a narrative
description of each step.
1-3.1.1 Step 1 -Site Analysis: Collect and Analyze Information on Existing Conditions
Site analysis shall be submitted as part of the Existing Conditions Summary above. Part of the
information in this step should be used to help prepare the Construction Stormwater Pollution
Prevention Plan. Purpose of the Site Analysis is to provide for a Low Impact Development site
design that is intended to compliment the predeveloped conditions of the site.
1-3.1.2 Step 2 -Prepare Preliminary Development Layout
Based upon the analysis of existing site conditions, locate the buildings, roads, parking lots,
landscaping features, on -site stormwater management BMP's, and preliminary location of
stormwater treatment and retention/detention facilities fQr the proposed development.
1 . , - i , �i - - -_ w 1 , , _ , _ _ I.-
1-3.1.3 Step 3 -Perform Off -site Analysis (at Local Agency's Option): Use additional Sheets, if
necessary,
Ecology recommends that local governments require an off -site analysis for projects that add
51000 SF or more of new hard surfaces, or convert 3/4 acres of vegetation to lawn or landscape
areas, or convert 2.5 acres of forested area to pasture.
ff-site analysis extends to'/ mile downstream of the project site.
O
1-3.1.4 -Determine Applicable Minimum Requirements
Establish project size thresholds for the application of Minimum Requirements to new
development and redevelopment projects. Figures 2.4.1 Attached and 2.4.2 Attached
provide the same thresholds in a flow chart format. Based on the preliminary layout, determine
whether Minimum Requirements #1 through #5 apply to the project; or, whether Minimum
Requirements #1 through #9 apply.
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
Please note, that Minimum Requirement #1 through #5 may trigger additional Minimum
Requirements, such as Flow Control.
1
1-3.1.5 Step 5 - Prepare a Permanent Stormwater Control Plan
(Refer to this section of the Ecology Manual for requirements.)
1-3.1.6 Step 6 - Prepare a Construction Stormwater Pollution Prevention Plan (MR#2 -13
Elements)
- -- Refer to-Chapter-ll-3 - P-tanning fora detailed description -of each element. See -also -attached -------
Tables 4.1.1 (Source Control BMP's by SWPPP Element) and Table 4.2.1 (Runoff Conveyance
and Treatment BMP's by SWPPP Element).
See attached 13 Elements of a SWPPP, please complete and attached
1-3.1.7 Step 7 - Complete the stormwater site plan
The Stormwater Site Plan encompasses the entire submittal to the Local Agency with drainage
review authority. Refer to this section of the Manual for further clarification of each item and
what is required. See below:
Project Overview
• Existing Conditions Summary
• Off -site Analysis Report
• Permanent Stormwater Control Plan
• Construction Stormwater Pollution Prevention Plan
• Special Reports and Studies
• Other Permits
• Operation and Maintenance Manual
• Declaration of Covenant for Privately Maintained Flow Control and Treatment Facilities.
(See attached Drainage BMP Maintenance Covenant BMP Agreement)
• Declaration of Covenant for Privately Maintained On -site Stormwater BMP's (See
attached Drainage BMP Maintenance Covenant BMP Agreement)
• Bond Quantities Worksheet, if applicable
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
1-3.1.8 Step 8 -Check Compliance with all Applicable Minimum Requirements
A Stormwater Site Plan as designed and implemented should specifically fulfill all Minimum
Requirements applicable to the project. The Stormwater Site Plan should be reviewed to check
that these requirements are satisfied.
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
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• 1-2.5.2 Minimum Requirement #2 — Construction Storm water Pollution Prevention Plan (SWPP)
- All projects are required to complete Minimum Requirement 2.
Refer to the 13 Elements of the SWPP (See document below, complete and attach)
See attached Table 4.1.1, Table 4.2.1 and Table
Provide Engineering Calculations as an attachment for Sediment Ponds\Traps, Diversions,
Waterways and Runoff/Stormwater Detention Calculations,
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
Table 4.1.1 Source Control Es P's by SVVPPP Element
Element01
Element42
Elernenttl5
Elemen[A6
Eiement#R9
Element€11
ElementM12
Elenment#13
BMP or Element Manua
Preserve
Establish
Stabilize
Protect
Control
Maintain
Manage the
Protect Low
VegetationlMark
Construction
Soas
Slopes
Pollutants
BMPs
Project
Impact
Clearing Limits
Access
Develoement
BMPC101: Preserving Natural Vegetation
✓
BMP C102: Buffer Zones
✓
✓
BMP C103: High Visibility Plastic or Metal
✓
✓
Fence
BMPC105: Stabilized Construction
✓
Entrance I Ebt
BMP C106: Wheel Wash
✓
BMP C107: Construction Road/Parking
✓
Area Stabilization
BMP C120: Temporary and Permwent I
✓
✓
Seeding
13MPC121: Mulching
L ✓
✓
BMP C122: Nets and Blankets
I
J
�✓
✓
BMP C123: Plastic Covering
I
BMP C124: Sodding
✓
l
BMP C125: Topsoiling I Composting
✓
BMP C126: Polyacrylaride for Soil Erosion
✓
Protection
BMP C130: Surface Roughening
✓
✓
BMP C131: Gradient Terraces
✓
✓
BMP C140: Dust Control
✓
BMP C150: Materials On Hand
I
✓
✓
BMP C151: Concrete Handling
✓
BMP C152: Sawcutting and Surfacing
✓
Pollution Prevention
W
BMP C153: Material Delivery, Storage and
✓
Containment
BMP C154: Concrete V%shout Area
✓
BMP C160: Certified Erosion and
✓
✓
Sediment Control Lead
BMP C162: Scheduling
✓
Version Date: October 7, 2019 Previous Version Date: February 20, 2Q19
Table 4.2.1 Runoff Conveyance and Treatment BMP's by SWPPP Element
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Version Qate: October 7, 2019 Previous Version Qate: February 20, 2019
13 Elements of SWPPP
(Construction Stormwater Pollution Prevention Plan)
Please check On boxes to show that each element has been read and understood. Provide details where
applicable and if certain aspects are unnecessary or exempt, clearly justify. Details of the 13 Elements and the
correlating BMPs are listed Above from the 2014 Stormwater Management Manual for Western Washington
(SWMMWW). A link is provided on the City of Anacortes website, under Planning, Community, & Economic
Development Department, as well as under Stormwater on the Engineering Division of Public Work's page.
Owner Name
Site Address
Prepared By:
The Stormwater checklist or building permit determined that:
The 13 elements must be addressed
for construction activity adding under
2,000 sq, ft. of hard surface area.
€ These elements must be addressed
for construction activity adding 2,000
sq, ft. or more of hard surface area.
This means that an attached narrative
and site plan are required with this
document.
Under each element, provide the BMP's that will be applicable toyour project. Use the attached Tables
provided.
ELEMENT 1: Preserve Vegetation/Mark Clearing Limits
€ Before beginning land disturbing activities, including clearing and grading, clearly mark all clearing
limits, sensitive areas and their buffers, and trees that are to be preserved within the construction area.
E. Retain the duff layer, native top soil, and natural vegetation in an undisturbed state to the maximum
degree practical.
fn� I Vr ,Ce.
ELEMENT 2: Establish Construction Access
€ Limit construction vehicle access and exit to one route, if possible.
€ Stabilize access points with a pad of quarry spalls, crushed rock, or other equivalent BMPs, to minimize
tracking onto roads.
€ Locate wheel wash or tire baths on site, if the stabilized construction entrance is not effective in
preventing tracking sediment onto roads.
€ If sediment is tracked off site, clean the affected roadway thoroughly at the end of each day, or more
frequently as necessary (ex: wet weather). Remove sediment from roads by shoveling, sweeping, or
pick up and transport the sediment to a controlled sediment disposal area.
€ Conduct street washing only after sediment is removed in accordance with the above bullet.
€ Control street wash wastewater by pumping back on site or otherwise preventing it from discharging
into systems tributary to 'waters of the State. ) /
�'r1 n,44 C,_....i.. t iVl- � ""' I-)`L 1', ,�L/t JL je'. _¢ry 'S �1� t1
Version Date: October 7, 2Q19 Previous Version Date: February 20, 2019
ELEMENT 3: Control Flow Rates
€ Protect properties and waterways downstream of development sites from erosion and the associated
discharge of turbid waters due to increases in the velocity and peak volumetric flow rate of stormwater
runoff from the project site.
€ Where necessary to comply with the bullet above, construct stormwater retention or detention facilities
as one of the first steps in grading. Assure that detention facilities function properly before constructing
site improvement (e.g. impervious surfaces).
€ If permanent infiltration ponds are used for flow control during construction, protect these facilities from
siltation during the construction phase.
�. ( / ,l
ELEMENT 4: Install Sediment Controls
€ Design, install, and maintain effective erosion controls and sediment controls to minimize the discharge
of pollutants.
€ Construct sediment control BMPs (sediment ponds, traps, filters, etc.) as one of the first steps in
grading. These BMPs shall be functional before other land disturbing activities take place.
€ Minimize sediment discharges from the site. The design, installation and maintenance of erosion and
sediment controls must address factors such as the amount, frequency, intensity and duration of
precipitation, the nature of resulting stormwater runoff, and soil characteristics, including the range of
soil particle sizes expected to be present on the site.
€ Direct stormwater runoff from disturbed areas through a sediment pond or other appropriate sediment
removal BMP, before the runoff leaves a construction site or before discharge to an infiltration facility.
Runoff from fully stabilized areas may be discharged without a sediment removal BMP, but must meet
the flow control performance standard in Element #3, bullet #1.
€ Locate BMPs intended to trap sediment on -site in a manner to avoid interference with the movement of
juvenile salmonids attempting to enter off -channel areas or drainages.
€ Provide and maintain natural buffers around surface waters, direct stormwater to vegetated areas to
increase sediment removal, and maximize stormwater infiltration.
€ Where feasible, design outlet structures that withdraw impounded stormwater from the surface to avoid
discharging_lsediment that is still suspended lower in the water column.
ELEMENT 5: Stabilize Soils
€ Stabilize exposed and unworked soils by application of effective BMPs that prevent erosion. Applicable
BMPs include, but are not limited to: temporary and permanent seeding, sodding, mulching, plastic
covering, erosion control fabrics and matting, soil application of polyacrylamide (PAM), the early
application of gravel base early on areas to be paved, and dust control.
€ Control stormwater volume and velocity within the site to minimize soil erosion.
€ Control stormwater discharges, including both peak flow rates and total stormwater volume, to minimize
erosion at outlets and to minimize downstream channel and stream bank erosion.
€ Soils must not remain exposed and unworked for more than the time periods set forth below to prevent
erosion.
o During the dry season (May 1 — Sept 30): 7 days
o During the wet season (Oct 1 — Apr 30): 2 days
€ Stabilize soils at the end of the shift before a holiday or weekend if needed based on the weather
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
forecast.
€ Stabilize soil stockpiles from erosion, protect with sediment trapping measures, and where possible, be
located away from storm drain inlets, waterways, and drainage channels.
€ Minimize the amount of soil exposed during construction activity.
€ Minimize the disturbance of steep slopes.
€ Minimize soil compaction and, unless infeasible, preserve topsoil.
12.rr` _ / 7MO / 'f0�- "iits
ELEMENT 6: Protect Slopes
€ Design and construct cut -and -fill slopes in a manner to minimize erosion. Applicable practices include,
but are not limited to, reducing continuous length of slope with terracing and diversions, reducing slope
steepness, and roughening slope surfaces (Ex: track walking).
€ Divert off -site stormwater (run-on) or ground water away from slopes and disturbed areas with
interceptor dikes, pipes, and/or swales. Off -site stormwater should be managed separately from
stormwater generated on the site.
€ At the top of slopes, collect drainage in pipe slop drains or protected channels to prevent erosion.
o *Temporary pipe slope drains must handle the peak volumetric flow rate calculated using a 10-
minute time step from a Type 1A, 10-year, 24-hour frequency storm for the developed condition.
Alternatively, the 10-year, 1-hour flow rate predicted/indicated by an approved continuous runoff
model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing
land cover condition for predicting flow rates from tributary areas outside the project limits. For
tributary areas on the project site, the analysis must use the temporary or permanent project
land cover condition, whichever will produce the highest flow rates. If using the Western
Washington Hydrology Model (WWHM) to predict flows, bare soil areas should be modeled as
"landscaped" area.
o Where 15-minute time steps are available in an approved continuous runoff model, they may be
used directly without a correction factor.
€ Place excavated material on the uphill side of trenches, consistent with safety and space
considerations.
€ Place check dams at regular intervals within constructed channels that are cut down a slope.
€ Consider soil types and its potential for erosion.
€ Stabilize soils on slopes, as specified in Element 5.
€ BMP combinations are the most effective method of protecting slopes with disturbed soils. Ex: Use both
mulching and straw erosion control blankets.
Version Date; October 7, 2019 Previous Version Date: February 20, 2019
ELEMENT 7: Protect Drain Inlets
€ Protect all storm drain inlets made operable during construction so that stormwater runoff does not
enter the conveyance system without first being filtered or treated to remove sediment.
€ Clean or remove and replace inlet protection devices when sediment has filled one-third of the available
storage (unless a different standard is specified by the product manufacturer).
€ Where possible, protect all existing storm drain inlets so that stormwater runoff does not enter the
conveyance system without first being filtered or treated to remove sediment.
€ Keep all approach roads clean. Do not allow sediment and street wash water to enter storm drains
without prior and adequate treatment unless treatment is provided before the storm drain discharges to
waters of the State.
€ Inlets should be inspected weekly at a minimum and daily during storm events.
fry i i , nt c
ELEMENT 8: Stabilize Channels and Outlets
€ Design, construct, and stabilize all on -site conveyance channels to prevent erosion from the fo!!oti^ring
expected peak flows:
o "Channels must handle same peak volumetric flow rate as temporary pipe slope drains listed in
Element 6, above.
€ Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent
streambanks, slopes, and downstream reaches at the outlets of all conveyance systems.
€ The best method for stabilizing channels is to completely line the channel with a blanket product first,
then add check dams as necessary to function as an anchor and to slow the flow of water.
ELEMENT 9: Gontrol Pollutants
€ Design, install, implement, and maintain effective pollution prevention measures to minimize the
discharge of pollutants.
€ Handle and dispose of all pollutants, including waste materials and demolition debris that occur on -site
in a manner that does not cause contamination of stormwater.
€ Provide cover, containment, and protection from vandalism for all chemicals, liquid products, petroleum
products, and other materials that have the potential to pose a threat to human health or the
environment. On -site fueling tanks must include secondary containment. Secondary containment
means placing tanks or containers within an impervious structure capable of containing 110% of the
volume contained in the largest tank within the containment structure. Double -walled tanks do not
require additional secondary containment.
€ Conduct maintenance, fueling, and repair of heavy equipment and vehicles using spill prevention and
control measures. Clean contaminated surfaces immediately following any spill incident.
€ Discharge wheel wash or tire bath wastewater to a separate on -site treatment system that prevents
discharge to surface water, such as closed -loop recirculation or upland land application, or to the
sanitary sewer, with local sewer district approval. Wheel wash or tire bath wastewater should not
include wastewater from concrete washout areas.
€ Apply fertilizers and pesticides in a manner and at application rates that will not result in loss of
chemical to stormwater runoff. Follow manufacturers' label requirements for application rates and
procedures.
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
€ Use BMPs to prevent contamination of stormwater runoff by pH -modifying sources. The sources for this
contamination include, but are not limited to: bulk cement, cement kiln dust, fly ash, new concrete
washing and curing waters, waste streams generated from concrete grinding and sawing, exposed
aggregate processes, dewatering concrete vaults, concrete pumping, and mixer washout waters. Adjust
the pH of stormwater if necessary to prevent violations of the water quality standards.
€ Assure that washout of concrete trucks is performed off -site or in designated concrete washout areas
only. Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets, or
streams. Do not dump excess concrete on site, except in designated concrete washout areas. Concrete
spillage or concrete discharge to surface waters of the State is prohibited. Do not use upland land
applications for discharging wastewater from concrete washout areas.
€ Obtain written approval from Ecology and provide to the City before using chemical treatment other
than CO2 or dry ice to adjust pH.
€ Woody debris may be chopped and spread on site.
€ Conduct 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 using spill prevention measures, such as drip pans.
€ Clean contaminated surfaces immediately following any discharge or spill incident. Emergency repairs
may be per)forme ,on -site using temporary plastic placed beneath and, if raining, over the vehicle.
ELEMENT 10: Control De -Watering
€ Discharge foundation, vault, and trench dewatering water, which have characteristics similar to
stormwater runoff at the site, into a controlled conveyance system before discharge to a sediment trap
or sediment pond.
€ Discharge clean, non -turbid de -watering water, such as well -point ground water, to systems tributary to,
or directly into surface waters of the State, as specified in Element 8, provided the de -watering flow
does not cause erosion or flooding of receiving waters or interfere with the operation of the system. Do
not route clean dewatering water through stormwater sediment ponds. Note that "surface waters of the
State" may exist on a construction site as well as off site; for example, a creek running through a site.
€ Handle highly turbid or contaminated dewatering water separately from stormwater.
€ Other treatment or disposal options may include:
1. Infiltration
2. Transport off -site in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that
does not pollute state waters.
3. Ecology -approved on -site chemical treatment or other suitable treatment technologies.
4. Sanitary or combined sewer discharge with local sewer district approval, if there is no other
option.
5. Use of a sedimentation bag with outfall to a ditch or swale for small volumes of localized
dewatering.
€ Construction equipment operation, clamshell digging, concrete tremie pour, or work inside a cofferdam
can create highly turbid or contaminated dewatering water.
€ Discharging sediment -laden (muddy) water into waters of the State likely constitutes a violation of water
quality standards for turbidity. The easiest way to avoid discharging muddy water is through infiltration
and preservinq vegetation.
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
ELEMENT 11: Maintain BMPs
`N�
€ Maintain and repair all temporary and permanent erosion and sediment control BMPs eededt to
assure conti uri ecTp�erformance of their intended function in accordance with BMP specifications.
€ Remove all temporary erosion and sediment control BMPs within 30 days after achieving final site
stabilization or after the temporary BMPs are no longer needed. Some temporary erosion and sediment
control BMPs are bio-degradable and designed to remain in place following construction such as
compost socks.
€ Provide protection to all BMPs installed for the permanent control of stormwater from sediment and
compaction. All BMPs that are to remain in place following completion of construction shall be
examined and placed in full operating conditions. If sediment enters the BMPs during construction, it
shall be removed and the facility shall be returned to the conditions specified in the construction
documents.
€ Remove or stabilize trapped sediment on site. Permanently stabilize disturbed soil resulting from
rnmr %inl of RAAPc nr ltariPtatlnn t
ELEEtIIEFdT 12: Manage the Project —Projects subject to Minimum Requirements 1-9 must have a Certified
Erosion and Sediment Control Lead (CESCL) for site inspections. Projects subject to Minimum Requirements
1-5 do not require the inspector to be certified. By the initiation of construction, the SWPPP must identify the
CESCL or inspector, who shall be present on -site or on -call at all times.
€ Phase development projects to the maximum degree practicable and take into account seasonal work
limits to prevent soil erosion and prevent transporting sediment from the site during construction.
€ Inspection and monitoring — Inspect, maintain, and repair all BMPs as needed to assure continued
performance of their intended function.
€ Maintain, update, and implement the SWPPP.
€ Clearing and grading activities for developments shall be permitted only if conducted using an approved
site development plan (e.g., subdivision approval).
€ From Oct 1 through Apr 30, clearing, grading, and other soil disturbing activities is permitted only if
shown that the site operator will prevent silt -laden runoff from leaving the site through a combination of
the following:
1. Site conditions including existing vegetative coverage, slope, soil type, and proximity to
receiving waters.
2. Limit activities and the extent of disturbed areas.
3. Proposed erosion and sediment control measures.
Weather conditions can influence the seasonal limitation on site disturbance. The City of Anacortes has
the authority to take enforcement action per AMC 19.76 Stormwater.
€ The following activities are exempt from the seasonal clearing and grading limitations:
1. Routine maintenance and necessary repair of erosion and sediment control BMPs;
2. Routine maintenance of public facilities or existing utility structures that do not expose the soil or
result in the removal of the vegetative cover to soil
3. Activities where there is 100% infiltration of surface water runoff within the site in approved and
installed erosion and sediment control facilities.
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
ELEMENT 13: Protect Low Impact Development BMPS
€ If implementing any bioretention facilities or rain gardens, refer to the applicable BMP sections of the
Manual for requirements.
Applicant Signature Date
Version Date: October 7, 2019 Previous Version Date: February 20, 2019
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Soil Map —Skagit County Area, Washington
Map Unit Legend
Map Unit Symbr5l Map Unit Name Acres In A61 Percent of AOI
31 Clallam-Urban land complex, 0 14.9 44.6 /o
to 8 percent slopes
165 Xerorthents, 0 to 5 percent 18.3 54.7%
slopes
Totals for Area of Interest 33.5 10000%
USDA Natural Resources Web Soil Survey 919/2020
� Conservation Service National Cooperative Soil Survey Page 3 of 3
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Map Unit Description: Clallam-Urban land complex, 0 to 8 percent slopes ---Skagit County
Area, Washington
�kagiv county Area, Vwaa"U "Ou
my
Map Unit Setting
National map unit symbol: 2hvf
Elevation: 30 to 150 feet
Mean annual precipitation: 23 inches
Mean annual air temperature: 48 degrees F
Frost -free period: 160 to 200 days
Farmland classification: Not prime farmland
Map Unit Composition
Clallam and similar soils: 45 percent
Urban land: 40 percent
Minor components: 5 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Clallam
Natural Resources
- Conservation Service
Setting
Landform: Hillslopes
Parent material: Glacial drift
Typical profile
H1- 0 to 11 inches: gravelly ashy loam
H2 - 11 to 27 inches: very gravelly loam
H2 - 27 to 60 inches: very gravelly sandy loam
Properties and qualities
Slope: 0 to 8 percent
Depth to restrictive feature: More than 80 inches; 20 to 40 inches to
densic material
Drainage class: Moderately well drained
Capacity of the most limiting layer to transmit water (Ksat): Very low
to moderately low (0.00 to 0.06 in/hr)
Depth to water table: About 18 to 36 inches
Frequency of flooding: None
Frequency of ponding: None
Available water capacity. Very low (about 2.6 inches)
Interpretive groups
Land capability classification (irrigated): 3w
Land capability classification (nonlrrigated): 4s
Hydrologic Soil Group: C
Forage suitability group: Limited Depth Soils (G002XN302WA)
Other vegetative classification: Limited Depth Soils
(G002XN302WA)
Hydric soil rating: No
V;�eb Soil Sur�ey
fJational Cvoperair�e Soil S!irvey
9/9/2020
Page 1 of 2
Map Unit Description: Clallam-Urban land complex, 0 to 8 percent slopes ---Skagit County
Area, Washington
Description of Urban Land
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 8
Hydric soil rating: No
Minor Components
Bow
Percent of map unit: 5 percent
Landform: Terraces
Other vegetative classification: Seasonally Wet Soils
(G002XN202WA)
Hydric soil rating: Yes
Data Source Informati®n
Soil Survey Area: Skagit County Area, Washington
Survey Area Data: Version 20, Jun 5, 2020
Natural Resources
Conservation Service
1n1eb Soil Survey
National Cooperative Soil Survey
9i9i2020
Page 2 of 2
Map Unit Description: Xerorthents, 0 to 5 percent slopes ---Skagit County Area, Washington
Kagut k6OLIMLy AreOIg US HU H W�
Map Unit Setting
National map unit symbol: 2htw
Elevation: 0 to 250 feet
Mean annual precipitation: 15 to 60 inches
Mean annual air temperature: 48 to 50 degrees F
Frost free period: 180 days
Farmland classification: Not prime farmland
Map Unit Composition
Xerorthents and similar soils: 95 percent
Minor components: 5 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Xerorthents
Setting
Landform: Hillslopes, flood plains
Parent material: Human transported and disturbed material
Typical profile
inches: variable
H2 - 7 to 60 inches: stratified extremely gravelly sandy loam
Properties and qualities
Slope: 0 to 5 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Excessively drained
Capacity of the most limiting layer to transmit water (Ksat): High
(1,98 to 5.95 in/hr)
Depth to water table: About 24 to 72 inches
Frequency of flooding: None
Frequency of ponding: None
Available water capacity: Very low (about 2.7 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 7e
Hydrologic Soil Group: A
Hydric soil rating: No
Minor Components
Bow
Percent of map unit: 5 percent
Landform: Terraces
Other vegetative classification: Seasonally Wet Soils
(G002XN202WA)
Natural Resources Web Soil Survey
Conservation Service National Cooperative Soil Sun;ey
e�srto?�
;'age I or 2
Map Unit Description: Xerorthents, 0 to 5 percent slopes -..Skagit County Area, Washington
Hydric soil rating: Yes
®ata Source inforrnati®n
Soil Survey Area: Skagit County Area, Washington
Survey Area Data: Version 20, Jun 5, 2020
at �-e Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Sail Survey
sisizo2o
Page 2 of 2
�Ei I (�F n ,,f;l �I I P'' `,
DEFERRED SUIBMITTAL: PROVIDE A TEST REPORT FROM SOILS SUPPLIER TO THE BUILDING DEPT.
PROJECT INFORMATION "Model Soil Management Plan for BMP T5.13" age # of pages
Camniata nil information nn nacre 1 9 only cite address and nermit number on additional napes.
Site Address / Lot No.:
-D f
2,Z
Permit Type:
Permit Number:
Permit Holder:
„ ' Phone:
Mailing Address:
0
r UJA q2 a
Contact Person: Da
i N Phone:
Plan Pre ared By:
e
ATTACHMENTS REQUIRED (Check pl}re4latir-ed items that are attached to this plan)
Site Plan showing, to scale: Areas of undisturbed native vegetation (no amendment required)
New planting beds and turf areas (amendment required)
Type of soil improvement proposed for each area
Soil test results (required if proposing custom amendment rates)
Product test results for proposed amendments
AREA # (shoerld match Area # on Site Flan)
PLANTING TYPE _Undisturbed native vegetation
_Turf
Planting Beds Other:
SQUARE FOOTAGE OF THIS AREA: square feet
SCARIFICATION
_ inches (depth) of scarification needed to achieve finished total 12" loosened depth.
Subsoil will be scarified
PRE -APPROVED
of compost or imported topsoil applied
AMENDMENT METHOD:
Topsoil import
_ Amend with compost
Stockpile and amend
_inches
X 3.1 (conversion factor, inches to cubic vards)
= cu. yards per 1,000 sq. ft.
X _ ,000s sq.ft. in this area tp
= cubic yards of amendment
PRODUCT:
QUANTITY:A4.CU. YDS.
( cu. yds. stockpiled)
needed to cover this area to designated depth)
CUSTOM AMENDMENT
Attach test results and calculations.
import
inches organic matter or topsoil import
PRODUCT:
.Topsoil
_ Topsoil & compost lift
X 3d1
Amend
= cu. yards ! 1,000 sq. ft.
_
Stockpile and amend
X ,000s sq. ft. in this area
C. cu, yds. stockpiled)
_
= cubic yards of amendment r —> -> >
QUANTITY: CU. YDS.
MULCH
_ ,000 sq.ft.
PRODUCT:
X 6.2 (conversion, to give 2 inch mulch depth)
= cubic yards of mulch
QUANTITY:. CU. YDS.
TOTAL AMENDMENT/TOPSOIL/MULCH FOR ALL AREAS (complete on pctQe 1 only, 1phtlirtg all areas/pages in this Plan)
❑ Product #1: ❑Quantity: cu. yds.
❑ Test Results: % organic matter C:N ratio <25:1(except mulch, or <35:1 for native plants) "stable" (yes/no)
❑ Product #2: ❑Quantity: cu. yds.
❑ Test Results: % organic matter C:N ratio <25:1 (except mulch, or <35:1 for nativeplants) "stable" es/no)
❑ Product #3: ❑ Quantity: cu. yds.
❑ Test Results: % organic matter C:N ratio <25:1 (except mulch, or <35:1 for native plants) "stable" (yes/no)-
-
Date:
Inspector:
Approved:
Revisions Required:
Date:
Inspector:
Approved:
Revisions Required:
Version Date: ®ctober 7, 2019 Previous Version Date: February 20, 2019
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Phase 1 Municipal Stormwater Permit
APPENDIX 7 - Determining Construction Site Sediment
Damage Potential
The following rating system allows objective evaluation of a particular development site's potential to
discharge sediment. Permittees may use the rating system below or develop alternative process
designed to identify site -specific features which indicate that the site must be inspected prior to clearing
and construction. Any alternative evaluation process must be documented and provide for equivalent
environmental review.
Step 1 is to determine if there is a sediment/erosion sensitive feature downstream of the development
site. If there is such a site downstream, complete Step 2, assessment of hydraulic nearness. If there is a
sediment/erosion sensitive feature and it is hydraulically near the site, go to Step 3 to determine the
construction site sediment transport potential.
STEP 1—Sediment/Erosion Sensitive Feature Identification
Sediment/erosion sensitive features are areas subject to significant degradation due to the effect of
sediment deposition or erosion. Special protection must be provided to protect them,
Sediment/erosion sensitive features include but are not limited to:
i. Salmonid bearing fresh water streams and their tributaries or freshwater streams that would be
h Salmonid bearing if not for anthropogenic barriers;
ii, Lakes;
iii. Category I, II, and III wetlands;
iv. _Marine near -shore habitat;
NU v. Sites containing contaminated soils where erosion could cause dispersal of contaminants; and
d6vi. Steep slopes (25% or greater) associated with one of the above features.
Identify any sediment/erosion sensitive features, and proceed to Step 2. If there are none, the
assessment is complete.
STEP 2 —Hydraulic Nearness Assessment
Sites are hydraulically near a feature if the pollutant load and peak quantity of runoff from the site will
not be naturally attenuated before entering the feature. The conditions that render a site hydraulically
near to a feature include, but are not limited to, the following:
i. The feature or a buffer to protect the feature is within 200 feet downstream of the site.
ii. Runoff from the site is tight -lined to the feature or flows to the feature through a channel or
ditch.
A site is not hydraulically near a feature if one of the following takes place to provide attenuation before
runoff from the site enters the feature:
i. Sheet flaw through a vegetated area with dense ground cover
Flow through a wetland not included as a sensitive feature
Appendix 7- Determining Sediment Damage Potential - Flugust 1, "Lo19
Page 1 of 4
Phase l Municipal Stormwater Permit
iii. Flow through a significant shallow or adverse slope, not in a conveyance channel, between the
site and the sensitive feature.
Identify any of the sediment/erosion sensitive features from Step 1 that are hydraulically near the site,
and proceed to Step 3. If none of the sediment/erosion sensitive features are hydraulically near the site
the assessment is complete.
STEP 3 —Construction Site Sediment Transport Potential
Using the worksheet below, determine the total points for each development site. Assign points based
on the most critical condition that affects 10% or more of the site.
If soil testing has been performed on site, the results should be used to determine the predominant soil
type on the site. Otherwise, soil information should be obtained from the county soil survey to
determine Hydrologic Soil Group (Table of Engineering Index Properties for step LD) and Erosion
Potential (Table of Water Features for step LE).
When using the county soil survey, the dominant soil type may be in question, particularly when the site
falls on a boundary between two soil types or when one of two soil types may be present on a site. In
this case, the soil type resulting in the most points on the rating system will be assumed unless site soil
tests indicate that another soil type dominates the site.
Use the point score from Step 3 to determine whether the development site has a high potential for
sediment transport off of the site.
Total Score
<100 Low'
>_100 High
Transport Rating
A high transport rating indicates a higher risk that the site will generate sediment contaminated runoff,.
Apl�ettrlr � 7- Jeternrinrr;�) Serlinrent /Jamarle Potential - A!tgust 1, ?(l19 --
Page 2 oF4
Phase I Municipal Stnrmwater Permit
Construction Site Sediment Transport Potential WOrksheet
A. Existing slope of site (average, weighted by aerial extent): Points
rless................................................................. ........;
>2-5%.......................................................................................................5
B. Site Area to be cleared andjor graded:
<5,000 sq.............................................................. .. ._...........,...1/
5,000 sq. ft. 1 acre 04,9 w 94V gas 4 44M 1 4 1 a &A a 6 A W a a 4 1 m.l w a on I Is 4 tvvwvinf Am ................30
>1
acres
...................................,,.....,,.....,.......................,....,...,...,...._........50
C. Quantity o/fcu oi•fill on site; �
t< azubic yards.................................................................................... 0
500 — 51000 cubic yards............................................................................ 5
>5,000—10,000 cubic yards...................................................................10
>10,000 — 20,000 cubic yards................................................................. 25
>20,000 cubic yards................................................................................40
®. Runoff potential of predominant soils (Soil Conservation Service):
Hydrologicsoil group A.....................................................:.......................0
Hydrologic soil group 8........................................................................::.10
Hydrologic soil grou4.................................................................,., d L20
Hydrologicsoil group D...........................................................................40
E. Erosion Potential of predominant soils (Unified Classification System);
GW, GP, SW, SP soils ... ............................. tot ............... TEAM ITS ................._.,,,..0
Dual classifications (GW-GM, GP -GM, GW-GC,
GP -GC, SW-SM, SW -SC, SP-SM, SP-SC)..........................................10
Appendix 7- Deter-mininc� Sediment Damage Potential -August 1, 2019 Page 3 of 4
Phase / Municipal Stormwater Permit
GM, GC, SM. SC soils ....................... 7a20
ML, CL, MH, CH soils......................................................... ....................40
F. Surface or Groundwater entering site identified and inttans ed1:
Yes............................................................. ......................................ED
No.......................... 4 A I A .......................,........._.................,..,,... ,..............25
G. Depth of cut or height of fill >10 feet:
Yes..........................................................................................................25
No.................................................................
a a ........................
Do DO
FI. Clearing and grading will occur in the wet season {flctober 1—May 1�:
No........................................................................................................f " J
TOTALPOINTS*
A A 4 4 1
a A d 1
6 a A A 4 4 1
A 0 7 A A A A A I A 4 1 4 a
F a w ...................,..............,.............,.....................,......
1 If no surface or ground water enters the site, assign 0 paints.
Appendix 7- Determining Sediment Damage Potential -August 1, 2019
Page 4 of 4
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