HomeMy WebLinkAboutPermit File BLD-2020-0298 1220 34th Street (2) ,, e Storm Water Minimum Requirements #2
} ENGINEERING DEPARTMENT
904 6th Street Anacortes,WA 98221
\+ -c4, www.anacorteswa.gov
\,1.2.40
Official Use Only: (Information to Inspectors)
Required Storm Water Facility and other related requirements:
Project Address: 1220 34th St. Submittal Date:
Parcel Number: P57082 Revision Number:
Permit Number: Acceptance Date (COA):
Reviewer:
FRONT OF REPORT
Submittal Checklist:
o TAB 1 - Drainage Analysis — Minimum Requirement #2
o APPENDIX 1 - Survey performed by a Professional Land Surveyor
o APPENDIX 2 - Model Soil Management Plan for BMP T5.13
o APPENDIX 3 - Determining Construction Site Sediment Damage Potential (Appendix 7)
o APPENDIX 4 - Site Plan with all applicable information (Minimum Size 11x17 — 30 scale)
o APPENDIX 5 - Documented Site Photos (North, South, East and West)
Project Description: (What is it you are looking to do? Provide details regarding, but not limited to, Lot SF,
Home SF, New and Replaced Hard Surface)
Construction of an Accessory Dwelling Unit, attached to existing house. Existing hard surface for the property
is 3627 s.f., which includes buildings under roof, paved parking and driveways and walkways. New proposed
hard surface is to be 1041 s.f. which is the addition under roof. Total hard surface will then be 4668 s.f. on
this 10,796 s.f. property.
Existing Site Conditions 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 PhasinglSequence)
The site has very little slope, about 2% slope from front of property(north)to back(south).
There are no critical areas adjacent to the site, and there are no erosion problem areas.
No soil analysis was done for this site, but a proposed stormwater drainage plan has been submitted.
Construction phasing/sequence: plan is to build during warm, non-rainy season. BMP's and erosion
control to be installed first, then excavation and foundation, then framing and trusses. Goal is to get
watertight (roofing and building wrap) before rainy season.
Version Date: December 19, 2018
After exterior construction is complete any disturbed lawn and landscape will be restored.
Developed Conditions Summary:
(Additionally, to be shown on the site plan. Identify cut and fill areas, proposed slopes of all hard
surfaces , proposed contours)
There is very little slope to the site. Cut area will be to accommodate crawl space of addition. There will be
no fill area. There will be no additional paved areas.
Site Sediment Transport Score: Total Points (High\Low) (See Determining Construction Site
Sediment Damage Potential (Appendix 7)
Complete the Applicability Requirements— Flow Chart (Figure 1-2.4.1 Attached, Figure 1-2.4.2 Attached
and Figure 1-2.5.1 Attached)
- Highlight the path and attach
DOE Stormwater Management Manual Minimum Requirements: (MR#1 to MR#5 only).
Refer to the 2012 Department of Ecology Manual, as amended in 2014 for further required information.
Version Date: December 19, 2018
Start Here
1
Does the site have 35% Yes See Redeveiopmen: Minimum
or more of existing Requirements and Flow Chart
impervious coverage? (Figure 1-2.4.2)-
No
Does the project convert 3,
■ acres or more of vegetation to
Does the project result in lawn or landscaped areas, or
5.000 square feet. or No convert 2.5 acres or more of
greater. of new plus native vegetation to pasture?
replaced hard surface
area?
No
Yes ,
Yes Does the project result in 2.000
square feet, or greater, of new plus
replaced hard surface area?
All Minimum Requirements
apply to the new and replaced
hard surfaces and converted Yes No
vegetation areas.
Does the project have land
Minimum Requirements #1 disturbing activities of 7.000
through #5 apply to the new Yes square feet or greater?
and replaced hard surfaces
and the land disturbed. No
■
Minimum Requirement#2
applies.
Figure 1-2.4_ 1
Flow Chart for Determining Requirements for
New Development
DEPARTMENT OF ateasea June 201f
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TAB 2 (MINIMUM REQUIREMENT#2)
• 1-2.5.2 Minimum Requirement#2 — Construction Stormwater 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.
Various BMP's will be utilized during construction of this project, and will be in place prior to
construction commencing.
Version Date: December 19, 2018
Table 4.1.1 Source Control BMP's by SWPPP Element
Element tli Element#2 Element 05 Element 46 Element 09 Element 011 Element 012 Element#13
Preserve Establish Protect Low
BMP or Element Name Stabilize Protect Control Maintain Manage the
Vegetation/Mark Construction Impact
Clearing Limits , Access 5ois Slopes Pollutants BMPs Project Developmenr
•
BMP C101: Preserving Natural Vegetation
BMP C102:Buffer Zones J ,/
BMP C103:High Visibility Plastic or Metal 1
Fence
BMPC105: Stabilised Construction J
Entrance/Exit
BMP C106: Wheel Wash J
BMPC107: Construction RoadlParking V
Area Stabilization
BMP C120:Temporary and Perrnsnent �
Seeding
BMP C121: Mulching J J
BMP C122: Nets and Blankets 1 V
BMP C123: Plastic Covering d
•
BMP C124: Sodding V
BMP C125: Topsoiling!Composting 1I
BMP C126: Polyacryianide for Soil Erosion
Protection
BMP C 131): Surface Roughening J ,I
BMP C131: Gradient Terraces d +/
BMP C140: Dust Control
BMPC150: Materials On Hand �/ J
BMPC151: Concrete Handling 1
BMP C152: Sawicutting and Surfacing
Pollution Prevention
BMP C153: Material Delivery,Storage and
Containment
BMP C154: Concrete Washout Area
BMP C160: Certified Erosion and J
Sediment Control Lead
BMP C162:Scheduling V
Version Date: December 19, 2018
Table 4.2.1 Runoff Conveyance and Treatment BMP's by SWPPP Element
Element 14 Bement 18 Element#13
Element 13 �sbll Element 116 I Element 07 Stabilize Element#9 Element 010 Protect Low
BMP or Element Name Control De-
Sediment Protect Protect Channels Impact
Control De- Imps
Flaw Rates Slopes Drain Inlets Pollutants Watering
Controls and Outlets 3erelopment
6NP C200: Interceptor Dike and Swale ✓ ✓
SLAP C201: Grams-tined Channels ✓
MAP C202:Channel Lining ✓
BaAP C203: Water Bars ✓ ✓ •
BMP C204: Pipe Slope Grams ✓
LIMP C206: Subsurface Drains ✓
8MP C206: Level Spreader ✓
LIMP C207: Check Darns ✓ ✓
8MP C206: Triangular Sift Dike(deotezt e ✓
Encased Check Den
BMP C209: Outlet Protection ✓
BMP C220: Stone Drain Inlet Protection f
BMP C231: Brush Barrier ✓ r ✓
BMP C232: Gravel Filler Berm ✓
HMP C233: Sit Fence ,/ ✓
BMP C234: Vegetated Strip ✓ ✓
BMP C235: Wattles ✓
BMP C236:Vegitetive Filtration ✓
BMP C240c Sediment Trap ✓ ✓
BMP C241: Temporary Sediment Pond ✓ ✓
BMP C2S0: Construction Montrealer ✓
Cherrlcal Treatment
BMP C251:Construction Storm aster ✓
Filtration
BMP C252 High pH Neutralization Using ✓
CO2
BMP C253:pH Control for High pH Water ✓
Version Date: December 19, 2018
13 Elements of SWPPP
(Construction Stormwater Pollution Prevention Plan)
Please check off 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: Gregory& Rikako Hill
Site Address: 1220 34th Street, Anacortes, WA 98221
Prepared By: Jim Dunlap, JD Design
The Stormwater checklist or building permit determined that:
❑ The 13 elements must be addressed ❑ These elements must be addressed
for construction activity adding under for construction activity adding 2,000
2,000 sq. ft. of hard surface area. 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, explain the best management practices (BMPs) used o!ustifv reasoning for
those that will not be used. If needed, please attach a narrative to further explain plans or justification.
ELEMENT 1: Preserve Vegetation/Mark Clearing Limits
i 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.
❑ Retain the duff layer, native top soil, and natural vegetation in an undisturbed state to the maximum
degree practical.
The lot is already fully developed and landscaped. The addition is going in an area that is lawn. There are
some mature trees on the property, and most of these are far from the construction zone. However there
is one tree that is close enough to the construction zone to warrant protection. A high visibility fence, at
drip line +6', will be installed around this tree.
The rest of the landscaping, besides lawn, should not be disturbed.
A silt fence will be installed that will help to define the construction area.
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.
n 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.
BMP C107 will be utilized. Construction access will be limited to existing paved parking/driveway.
If sediment is tracked off site the affected road way will be cleaned.
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.
Since the lot has such little slope it is not anticipated that neighboring sites would be affected by site erosion
or an impactful storm water flow.
BMP C233 will be utilized and silt fencing will be installed on the downslope sides of the construction area:
to the north of the construction area, and also along the entire east property line.
In addition BMP C235 straw wattles will be utilized as needed, to protect neighboring property to the east.
Version Date: December 19, 2018
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 sediment that is still suspended lower in the water column.
BMP C235 straw wattles will be utilized as needed to help control sediment and to protect the neighboring
property to the east.
There will also be natural buffers around the construction area since the site is already landscaped with lawn.
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
forecast.
❑ Stabilize soil stockpiles from erosion, protect with sediment trapping measures, and where possible, be
Version Date: December 19, 2018
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.
BMP C123: Exposed soil stockpiles will be covered with plastic.
BMP C121: Other exposed areas will be covered with mulching
ELEMENT 6: Protect Slopes
n 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.
n 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.
n BMP combinations are the most effective method of protecting slopes with disturbed soils. Ex: Use both
mulching and straw erosion control blankets.
There is not much slope to this site. However, BMP C233 Silt Fence will be installed around periphery of
construction area. In addition BMP C235 straw wattles will be utilized as needed.
Version Date: December 19, 2018
ELEMENT 7: Protect Drain Inlets
n 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.
BMP C220 Protecting drain inlets will be employed as needed, especially for 34th Street inlets ('M'Ave. inlets
should be far away from construction site. There is a drainage ditch, though, between the construction site and
34th Street so it is anticipated that sediment-exposed stormwater runoff may not reach these inlets.
ELEMENT 8: Stabilize Channels and Outlets
Design, construct, and stabilize all on-site conveyance channels to prevent erosion from the following
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.
The natural discharge location will be protected by BMP C233 Silt Fence.
Version Date: December 19, 2018
ELEMENT 9: Control 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.
❑ 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 performed on-site using temporary plastic placed beneath and, if raining, over the vehicle.
BMP C154 Designated Concrete Washout Area will be utilized. Concrete washout area will consist of plastic
tubs or will be built with a straw bale surround.
Version Date: December 19, 2018
All chemicals, liquid products, petroleum products, solvents and other potentially environmentally hazardous
products will be locked up safely on site.
No fueling or oil changes will be performed on site.
Contractor will be required to have a spill kit on site that is accessible by all workers on the project.
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 preserving vegetation.
No dewatering is anticpated on the site. If dewatering is required, however, then a sedimentation bag with
outfall to a drainage ditch will be utilized.
ELEMENT 11: Maintain BMPs
❑ Maintain and repair all temporary and permanent erosion and sediment control BMPs as needed to
assure continued performance 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
Version Date: December 19, 2018
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
removal of BMPs or vegetation.
BMP's will be inspected on daily basis and maintained and repaired as necessary.
Trapped sediment will be removed from site as needed. Sediment that enters the BMP's during construction
will be removed and the BMP will be returned to fully functioning state.
ELEMENT 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: December 19, 2018
The contractor will act as manager of BMP's and ensure that all BMP's are working as they should throughout
the course of construction. BMP's will be inspected and repaired as needed throughout the course of
construction.
This project will take place during the warm, dry season.
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.
//- {
Appli nt e.. Date
Version Date: December 19, 2018
I--- -
TAB 5 (MINIMUM REQUIREMENT#5)
• Minimum Requirement#5—On-site Stormwater Management
All sites are required to utilize BMP T5.13 — Post Construction Soil Quality and Depth.
For each surface, consider the BMP's in the order listed for that type of surface. Use the first BMP that
is considered feasible. No other on-site Stormwater Management BMP is necessary for that surface.
Feasiblity shall be determined by evaluation against:
1. Design criteria, limitations and infeasiblity criteria identified for each BMP in this manual, and;
2. Competing needs criteria listed in Chapter V-5— On-site Stormwater Management.
Lawn and Landscaped Area:
• BMP T5.13: Post-Construction Soil Quality and Depth. (Attach Detail in Report)
Refer to this site for requirements and specifications. All projects are required to utilize this BMP.
http://www.soilsforsalmon.org/pdf/Soil BMP Manual.pdf
See below for the "Model Soil Management Plan for BMP T5.13" to be submitted with Drainage
Report and Application Material.
Version Date: December 19, 2018
PROJECT INFORMATION "Model Soil Management Plan for BMP T5.13" age# of pages
Complete all information on page 1;only site address and permit number on additional pages.
Site Address/Lot No.:
Permit Type: Permit Number:
Permit Holder: Phone:
Mailing Address:
Contact Person: Phone:
Plan Prepared By:
ATTACHMENTS REQUIRED (Check off required 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# (should match Area#on Site Plan)
PLANTING TYPE Turf _Undisturbed native vegetation
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 inches of compost or imported topsoil applied
AMENDMENT METHOD: X 3.1 (conversion factor, inches to cubic yards) PRODUCT:
Topsoil import =cu.yards per 1,000 sq. ft.
_Amend with compost X ,000s sq.ft. in this area
Stockpile and amend =cubic yards of amendment —>—>—>—>—> QUANTITY: CU.YDS.
( cu.yds. stockpiled) (needed to cover this area to designated depth)
CUSTOM AMENDMENT Attach test results and calculations.
Topsoil import inches organic matter or topsoil import PRODUCT:
Topsoil&compost lift X 3.1
Amend =cu.yards/ 1,000 sq. ft.
Stockpile and amend X ,000s sq.ft. in this area
( cu.yds. stockpiled) =cubic yards of amendment —*—*—*—*-* 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 page 1 only, totaling all areas/pages in this Plan)
❑ Product#1: ❑ Quantity: cu.yds.
Version Date: December 19, 2018
❑ 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 native plants) "stable"(yes/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:
APPENDIX 1 — Survey performed by a Professional Land Surveyor
Note: survey was submitted with permit application.
Version Date: December 19, 2018
APPENDIX 2— Model Soil Management Plan for BMP T5.13
Note: Document is provided under Minimum Requirement 5 in this document
Version Date: December 19, 2018
APPENDIX 3— Determining Construction Site Sediment Damage Potential (Appendix 7 — NPDES Phase
II Permit)
Note: See attached
Version Date: December 19, 2018
Western Washington Phase II 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 one 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 two, assessment of hydraulic nearness. If there is
a sediment/erosion sensitive feature and it is hydraulically near the site then go to step three to
determine the construction site sediment transport potential.
ii. 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 Salmonid bearing if not for anthropogenic barriers;
ii. Lakes;
iii. Category I, II, and III wetlands;
iv. Marine near-shore habitat;
v. Sites containing contaminated soils where erosion could cause dispersal of
contaminants; and
vi. Steep slopes (25% or greater) associated with one of the above features.
Identify any sediment/erosion sensitive features, and proceed to step two. If there are none the assessment
is complete.
iii. STEP 2 — Hydraulic Nearness Assessment
Version Date: December 19, 2018
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.
August 1, 2013, Modified January 16, 2015 Appendix 7- Determining Sediment Damage
Potential Page 1 of 3
Version Date: December 19, 2018
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:
iv. Sheet flow through a vegetated area with dense ground cover
v. Flow through a wetland not included as a sensitive feature
vi. 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 one that are hydraulically near
the site, and proceed to step three. If none of the sediment/erosion sensitive features are
hydraulically near the site, the assessment is complete.
vii. 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 1.D) and Erosion Potential (Table of Water Features for step 1.E)
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 Transport Rating
<100 Low
❑100 High
A high transport rating indicates a higher risk that the site will generate sediment contaminated
runoff.
1-t
Construction Site Sediment Transport Potential Worksheet
A. Existing slope of site (average, weighted by aerial extent): Points 2%
or less ...0
>2-5%
>5-10% 1
>10-15% 30
>15% 50
B. Site Area to be cleared andlor graded:
<5,000 sq. ft
5,000 sq. ft. — 1 acre 3
>1 acres 50
C. Quantity of cut andlor fill on site:
<500 cubic yards
500 — 5,000 cubic yards (;)
>5.000 — 10,000 cubic yards 10
>10,000—20,000 cubic yards 25
>20,000 cubic yards 40
D. Runoff potential of predominant soils (Natural Resources Conservation Service):
Hydrologic soil group A 0
Hydrologic soil group B 10
Hydrologic soil group C
Hydrologic soil group D 40
E. Erosion Potential of predominant soils (Unified Classification System): ,
GP, SW, SP soils 0
Dual classifications (GW-GM, GP-GM, GW-GC,
GP-GC, SW-SM, SW-SC, SP-SM, SP-SC) 10
GM, GCS SM, .SC soils
ML, CL, ; CH soils g
I:. Surface or Groundwater entering site identified and interceptedl:
Yes
No 25
G. Depth of cut or height of fill >10 feet:
Yes
No .0
H. Clearing and grading will occur in the wet season (October 1 — May 1): es 50
No
TOTAL POINTS
1 If no surface or groundwater enters site, give 0 points.
c 1220 34th STREET
•0) in ANACORTES, WASHINGTON
tr) in
to
-, ALLEY BMP C233
v NEAREST FIRE I (E)8" CONC. S.S. 10'-0'' SILT FENCE
•pop HYDRANT APPROX. - - 23-6 12'-0" 18'-0" 36=6''
Ip z 130' TO NORTHWEST :� / / m t
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i =
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���� Le � /• 1 �� \_ -_/ TIGHTLINE TO DITCH
ZL -
0/ 5 25 38" I I 1/2-
Jr
SITE PLAN LEGEND `w (E)WATER METERTEMPORARY SOIL
OWER POLE I / /
DMP CI5 STOCKPILE LOCATION.
(E)DRAINAGE DITCH DESIGNATED COVER WITH STRAW
CE)PAVED SURFACE ` - ONG-RETE�i1ASl4-OI T- _
1- OR VISQUEEN.
zCIE v\
O
BMP CI05
//� AREA OF ADDITION CONSTRUCTION ACCESS ALREADY
LT
LIJEXISTS AT EXISTING CONCRETE
N PARKING LOCATION
o I — PROPERTY LINE 34th STREET
w
Q
x BUILDING SETBACK
LINE OF BLDG. FOOTPRINT
DRAWN BY JAD ------ LINE OF ROOF SITE PLAN
SCALE I" = 20' — UTILITY LINE NORTH
SCALE: I" - 20'-0"
DATE 05/08/2020 SILT FENCE
APPENDIX 5 — Documented Site Photos (Show all directions of the site, including
frontage)
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fi' h` �* ..' ': . '' , ,& rA y*
Location: South side of lot Location: Southeast corner of lot
Description of photo: South side of lot looking Description of photo: Photo taken from
toward north side, area next to house where Southeast corner of lot, looking toward north,
ADU will go showing area next to house where ADU will
go
Photo taken by: Jim Dunlap
Photo taken by: Jim Dunlap
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4 l
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41 '. 1*fix ' At ' •
_ •tax. V,o vA. .t,in. f ix y
Location: Northeast corner of lot Location: North side of lot
Description of photo: Photo taken from Description of photo: Photo taken from
Northeast corner of lot, looking south, North side of lot next to house, looking
showing area next to house where ADU will south, showing area where ADU will go.
go
Photo taken by: Jim Dunlap
Photo taken by: Jim Dunlap