HomeMy WebLinkAboutsdp2022-00020_05 APPROVED STORMWATER PLANWorksheet A1
Medium & Large Project Report
Minimum Requirement # 1 : Preparation of Stormwater Site Plan
Complete the following:
Submit a site plan demonstrating the project. Refer to REFERENCE A1A for examples of Best Management
Practices (BMP's) that you can use. Remember that all site plans submitted for the project must be consistent
and accurate.
A Describe both existing and proposed site conditions
bullet point. Attach additional pages if needed. N x for the follovying items as applicable in the space below each1n.) axrrdi1l. *tt graposed. '
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Minimum Requirement # 2 : Constru on Stormwater Po ution Prevention P n SWPPP
A SWPPP is designed to be a stand-alone document that addresses construction stormwater management concerns. This
document is required to be kept by the contractor performing the work at the jobsite for reference and update during
the life of the project. Construction BMP's must be indicated on the stormwater site plan. REFERENCE B1A includes
diagrams of common BMP's that may be used on the site plan.
lll My completed SWPPP (WORKSHEET 8L or equivalent) is included in this application packet!
Minimum Requirement # 3 : Source Control of Pollution (not construction related)
The intent of source control is to prevent stormwater from coming in contact with pollutants. Source control BMps
can be operational or structural in nature. A roof over a material storage area is an example of a structural source
control BMP. Washing your vehicle on the lawn rather than in the street is an operational BMp. This requirement
is generally not applicable to Single Family Residences (SFRs); howeve; ways to minimize pollution from moving
downstream should be considered during the design phase of every project. Specifications on standard source control
BMPs that are applicable to various commercial and industrial-type facilities can be found in Volume lV of the 2014
Stormwater Management Manualfor Western Washington {SWMMWW) (continued on page 2).
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Mar 17 2023
Mar 31 2023
DEPARTMENT OF COMMUNITY DEVELOPMENT
621 Sheridan Street, Port Touznsend, I&H 98368
T eL: 360.37 9.4450 | Fax: 360.379.M51
Wcb: wwqz.co.icfferson.wa.us/communitvdevelt-roment
E mail: dcd@ccr.iefferson.wa.us Scan the QR
code to access
the digitalform
STORMWATER CAICULATION STORKSHEET
PARcEL #Oo t - oG I - OoS eRo:ecrlaeeucenrrunur: 5*r-a4 r\,r- C**1r*.n
DETERMINING STORMWATER MANAGEMENT REqUIREMENTS: This stormwater calculation worksheet should be completed first to
classify the proposal as "small," "medium," or "large." The size determines whether a Stormwater Site Plan is required in
conjunction with a stand-alone stormwater management permit application, building permit application, or other land use approval
application that involves stormwater review. The basic information will also be helpful for completing a Stormwater Site Plan, if
req uired.
Lond-disturbing dctivity is any activity that results in movement of earth, or a change in the existing soil cover (both vegetative and
non-vegetative) and/or the existing soil topography. Land disturbing activities include, but are not limited to clearing, grading, filling,
excavation, and compaction associated with stabilization of structures and road construction.
Notive vegetotion is vegetation comprised of plant species, other than noxious weeds, which reasonably could have been expected
to naturally occur on the site. Examples include species such as Douglas fir, western hemlock, western red cedar, alder, big-leaf
maple, and vine maple; shrubs such as willow, elderberry, salmonberry, and salal; herbaceous plants such as sword fern, foam
flower, and fireweed.
PARCEL SIZE (I.E.. SITE)
An acre contains 43,560 square feet. Multiply the acreage by this figure.
sq/ftSize of parcel in square t,et ?+5, tlX-{
sizeofprr"a B.ba""r"s
LAND DISTURBING ACTIVITY. CONVERSION OF NATIVE VEGETATION. AND VOLUME OF CUT/FILL
@
Cut
sq/ft
sq/ft
0 sq/ft
O F'til q (cu/yd)
Well, utilities, etc.tL0
Construction site for structures
Driveway, parking, roads, etc.
Other compacted surface. etc.
Lawn, landscaping. etc.
Drainfield, septic tank, etc
lndicate Total Volumes of Proposed:
(lncludes BIUP T5_1.1.F :il Volume)
Answer the following two questions related to
conversion of native vegetation:
Does the project convert T, acres or more of
native vegetation to lawn or landscaped areas?
Circle: Yes @
Does the project convert 2Yz acres or more of
native vegetation to pasture?
Circle. Yes
sq/ft
sdft
sqift
sdft
Temporary construction area
Total l:nd Disturbance
Calculate the total area to be cleared, graded, filled,
excavated, and/or compacted for proposed developmentproject lnclude in this calculation the area to be cleared for.
stormwater calc worksheet QR @de - REV 513112A19 page 1 of 2
STORMWATER CALCULATIONS . IMPERVIOUS SURFACE
lmpervious surface is a hard surface that either prevents or slows the entry of water into the soil as under natural
conditions prior to development. A hard surface area which causes water to run off the surface in greater
quantities or at an increased rate of flow from the flow present under natural conditions prior to development.
Common impervious surfaces include, but are not limited to roof tops, walkways, patios, driveways, parking lots
or storage areas, concrete or asphalt paving, gravel roads, packed earthen materials, and oiled, macadam or other
surfaces which similarly impede the natural infiltration of stormwater.
TOTAL NEW + TOTAL EXISTING. sqlft "This amount witl be used to check total tot coverage.
Total New Total Erisfing
-sq/ft
sq/ft
NEW
Structures (all roof area)
Sidewalks
Patios
Solid Decks
(without infi ltration below)
Driveway, parking, roads, etc
Other
Driveway, parking, roads, etc
Other
ExrsrNG IJ tA
Structures (all roof area)
Sidewalks
Patios
Solid Decks
(without infi ltration below)
Divide the total existino
impervious surface above by the
size of the parcel and convert to
a percentage,%
DEVELOPMENT v. REDEVELOPMENT
Does the site have > 35o/o or more
existinq imoervious surface?->.)
+
yes
The proposal is considered redevelopment Answer
questions in Figure 2.4.2. Flow Chart for
Redevelopment to determine project size (next page).
- Applicants for "small" projects must comply only with Minimum Requirement #2-Construction Stormwater pollution prevention.
Please submit the Small Project Certification (Worksheet "s). The proponent is responsible for employing the 12 Elements to control
erosion and prevent sediment and other pollutants from leaving the site during the construction phase of the project. pick u p the
Construction Stormwater Pollution Prevention (SWPPP) Best Management practices (BMps) Fact Sheet.
- Applicants for "medium" projects-those that must meet only Minimum Requirements #1 through #5 must submit Worksheet 41
and 81, a stormwater site plan and a construction stormwater pollution prevention site plan {See Reference A1A and B1A for
guidance).).
- "Latge" projects-those that must meet all 9 Minimum Requirements- must submit Worksheet 41 and 81, a stormwater site plan
and a construction stormwater pollution prevention site plan (See Reference A1A and B1A for guidance). Large projects also may
require engineering. See Worksheet L to determine additional large project requirements.
F
no
The proposal is considered new development. Answer
questions in Figure 2.4.1 Flow Chart for New
Ilevelopment to determine project size (next page).
APPLICANT SIGNATURE By signing the Stormwater Calculation Worksheet, I as the applicant/owner attest that the information provided herein
is true and correct to the best of my knowledge. I also certify that this application is being made with the full
arlResrrutnlvr sreruarunr)
d
knowledge and consent of all owners
of the
stormwater mlc mrksheet QR ode - REV. 581t2019 page 2 ol 2
-J1Lb.L -lortt
l1-O rqft
Large Projects subject to Minimum Requirements #1
-9 must complete Worksheet A1 as applicable. Also
complete Workheet 81.
-r}
Does the project meet feasibility criteria
for full dispersion (see Worksheet C1)?+
I
I
I
Yes
I
I
Does the project discharge to a sub basin draining to salt water,
Dosewallips River, or Hoh River?
no Yes
no
Use List #3 on Worksheet A1 page 6.
No further action is needed.
ls the project in the Urban
Growth Area?
no
No Further action needed.
Demonstrate full dispersion
on site plan.
The proponent must submit
a stormwater report and site
plan prepared by a licensed
engineer that complies with
the 2012 Department of
Ecology Stormwater Man-
agement Manual for West-
ern Washin4on as amended
in 2014.
The report prepared by the
engineer must demonstrate
compliance with the LID
Performance Standard and
all minimum requirements.
noYes
ls the project on a parcel 5 acres or larger?
For each surface consider
the BMPS in the order listed
in List #1 page 5 in
Worksheet A1, except,
raingardens may not be
used. This process is equiva-
lent to tist #2 in the 2012
Department of Ecology
Stormwater Management
Manual for Western
Washington as amended in
20L4.
Worksheet L
Large Proiects
\+
Worksheet A1
Medium & large Project Report
Minimum Requirement # 3 : Source Control of Pollution (continued from page 1)
Check one of the following boxes that best represents your project with regards to MR #3.
M My project is a Single Family Residence (SFR) and after considering operational and structural measures to preventls\ stormwater from coming in contact with pollutants, I have:
X determined this MR to not be applicable. tr made appropriate adjustments to my project.
n My project is not a SFR and after reviewing Vol. lV of the SWMMWW I have determined that this MR is not
applicable because of the following reason:
My project is not a SFR and after reviewing Vol. lV of the SWMMWW I have determined that the following source
control BMPs are applicable to my project and shall be incorporated into the project design and operation.
Worksheet A1
Medium & Large Project Report
Minimum Requirement # 4 : Preservation of Natural Drainage Systems
Creating new drainage patterns results in more site disturbance and more potential for erosion and sedimentation during
and after construction. to the maximum extent possible, proponents must 1) maintain the natural on-site drainage
pattern and concentrated discharge location at the downstream property boundary, and 2) prevent erosion at and
downstream of the discharge location.
NOTE: All outfalls require energy dissipation. See Table 4.5.1 in Vol. V of the SWMMWW for minimum design standards
for rock protection at outfalls.
Choose the option below that best describes your project:
M The project site does not currently have any intermittent, seasonal, or continuous concentrated waterrc moving across any part of the property and the proposed improvements to the site will not create new
concentrated flow paths or not discharging to existing drainage systems.
The project site has existing concentrated flow drainage systems and outfalls. (NOTE: These items must
be graphically shown on the Site Plan or equivalent, to include: type, slope, dimensions, channel lining,
direction of flow, buffer; etc.) Select below how it will be addressed.
n This project will not alter the existing drainage system in any way. lf the existing outfall(s) show
signs of erosion and scour, energy dissipation measures will be installed or improved upon.
Construction activity of any kind will not occur within at least 10 ft. of the edge of the channelized
flow. BMP C102: BUFFER ZONES will be implemented during the life of the project to include visible
flagging or other demarcation technique.
The existing concentrated drainage system traversing the property will be impacted as part
of this project, as described in the space below and shown on the site plans. Engineering
calculations are required that show the altered drainage design can accommodate the existing
flows and the added runoff contributed by the project.
n
page 3 of 6
Worksheet A1
Medium & hrge Project Report
Minimum Requirement # 5 : On-site Stormwater Management
On-site stormwater management techniques shall be implemented where possible to accommodate the permanently
added stormwater runoff being generated by development. Some on-site stormwater management techniques provide
better stormwater detention and treatment than others; howeve4 they are not always appropriate for use due to varying
individual site characteristics. Therefore, techniques are presented to applicants on the next pages in a hierarchical order
and shall be considered for use in the order listed. The first technique on the list that is determined to be possible shall
be implemented. See WORKSHEET C to determine which techniques are feasible.
Runoff from developments occurring in drainage basins that drain directly or indirectly to a creek require a higher level
of stormwater management, thus, the techniques are presented in three lists below:
All properties will be in one of these three categories:
My project is located in a drainage subbasin that
drains to directly or indirectly to freshwater.
PROCEED to Page 5 to use LIST #1.
My Project will discharge to a subasin draining to
salt water; Dosewallips River, or Hoh River.
PROCEED to Page 6 to use LIST #3.
I
use LIST #1KMy project is a large project. Refer to Worksheet L. lf full dispersion isn't feasible,
(List #2 and List #1 are the same except raingardens are not permitted in List #2).
tr
Worksheet 81
Construction Protection: Medium and Large Projects
(SWPPP: Stormwater Potlution Prevention Plan) e
V Submit a site plan demonstrating the construction protective measures or best management practices that will
be used for the project during the construction phase.
The goal of this element is to preserve native vegetation and to clearly show the limits of disturbance.
Choose ony of the following that opply
M"The perimeter of the area to be cleared shall be marked prior to clearing operation with visible flagging, orange
plastic barrier fencing andlor orange silt fencing as shown on the SWPPP site plan. Vehicles will only be allowed
in the areas to be graded, so no compaction of the undeveloped areas will occur. lf this option is selected check
the BMPS you will use below:
C103 High Visibility
Fence
It is necessary to disturb the entire property during this project due to existing site conditions, property
constraints, and proposed design. I understand that all disturbed land not covered by hard surface at the end of
the project is subject to soil amendment requirements per BMP T5.13 Post-Construction Soil Quality and Depth.
The site was cleared as part of clearing activity that is subject to an enforcement action and will be re-vegetated.
Restoration may be necessary to comply with Critical Area Regulations or stormwater requirements. Buffer Zones-
BMP C102 may apply if Critical Areas exist on-site and buffer zones shall be protected.
Element 2: Construction Access
The goal of this element is to provide a stabilized construction entrance/exit to prevent or reduce or sediment
track out.
Chooy one of the following:,/
f/ fhe driveway to the construction area already exists and will be used for construction access. All equipment and
- vehicles will be restricted to staying on that existing impervious surface. lf sediment is tracked off site, the road-
way will be cleaned thoroughly at the end of each day.
ffi r,rUilized construction entrance will be installed prior to any vehicles entering the site, at the location+l shown on the SWPPP site plan. lf sediment is tracked off site, the roadway will be cleaned thoroughly at the end
of each day. lf this option is selected check the BMPS you will use below:
rIryn*ffi
Veeetation
Cl05 Stabilized
Construction Entrance /
Exit
Cl06 Wheel
Wash
n C107 Construction
Road / Parking Area
stabilization
page 1 of 6
Refer to REFERENCE B1A for examples of Construction Best Management Practices (BMP's) that you can use. The
activities that take place during construction are the highest risk for stormwater problems such as erosion and
sediment control (you may need to provide an additional site plan with greater detail for stormwater features. lf so,
make sure it is consistent with the primary site plan. Remember that all site plans submitted for the project must
be consistent and accurate).
Element L: Preserve Vegetation / Mark Clearing Limits
n
Worksheet 81
Construction Protection: Mediu.m and Large Projects
(SWPPP: Stormwater Pollution Prorcntion Plan)
Element 3: Control Flow Rates
The goal of this element is to construct retention or detention facilities when necessary to protect properties
and waterways downstream of development sites from erosion and turbid discharges.
Akifno ebmentdoes not opply to my project because (check ony thot apply):,,-
-:lA Site is mildly sloped l<5o/ol,
A There are no individually sloped sections greater than 7O%o,
V The bulk of the project is scheduled to occur during dry season (May 1-Sept 30)
Element 4: Sediment Control
The goal of this element is to construct sediment control BMPs that minimize sediment discharges from the
site.
Select one of the two statements applicoble to the project.
n
Y The site has already been stabilized and re-vegetated.
Sediment control BMPs shall be placed at the locations shown on the SWPPP Site Plan. lf this option is selected
check the BMPS you will use below:
C231 Brush Barrier n C233 Silt Fence n czas watrles
C232 Gravel Filter
Berm
C234Yesetated
Strio
Element 5: Stabilize Soils
The goal of this element is to stabilize exposed and unworked soils by implementing erosion control BMPs.
Select one of the three stotements applicoble to the project.
My project will ensure the following:. Soil stockpiles will be located within the disturbed area shown on the SWPPP Site Plan.. Soil excavated for the foundation will be backfilled against the foundation and graded to drain away from the
building.. No soils shall remain exposed and unworked for more than 7 days from May 1 to September 30 or more than
2 days from October 1to April 30.. Once the disturbed landscape areas are graded, the grass areas will be amended.. All stockpiles will be covered with plastic or burlap if left unworked.
This element does not opply to my project becouse:
SrJ
My project must implement specific BMP's to ensure compliance. (Check BMP's you will use on the next page).¤.9veJ"d)+A faxff z+.d?
Ow\
o(
but
¤dn
L on donc
V
V;taty ^ ."
{r^
tr
Workheet 81
Construction Protection: Medium and Large Projects
(SWPPP: Stormwater Potlution Prevention Plan) Y
f Ctzz tt.tr & gl*ketr I ctz+ soddi,tg I Ctlt Gradient
Cl25 Toosoil /
Comoostine
-
C235 Wattles
Element 5: Protect Slopes
The goalof this element is to design and construct cut-and-fillslopes in a mannerto minimize erosion
Select one of the two statements opplicoble to the project.
No cut slopes over 4 feet high or slopes steeper than 2 feet horizontal to 1 foot vertical, and no fill slopes over
4 feet high will exceed 3 feet horizontal to L foot vertical. Therefore, there is no requirement for additional
engineered slope protection.
The above checkbox is not checked. My submittal is designed by a licensed geologist to protect slopes. Based on
the licensed professionals recommendation (please attach their evaluation), the following BMP's will be used:
W
C120 Temporarv &+
Permanent Seedins
-
Cl2l Mulchins
-
- C123 Plastic Coverinsnl-J-l-l
Terraces
Cl40 Dust Control
C207 Check Dams
C208 Triansular Silt Dike
(Geotextile-Encased Check Dam
n
C120 Temporarv & Permanent
Seedins
C204 Pipe Slofe Drains
C205 Subsurface
Drains
N\K
Element 7: Protect Permanent Drain lnlets
The goal of this element is to protect storm drain inlets during construction to prevent stormwater runoff from
entering the conveyance system without being filtered or treated.
Select one of the three statements opplicoble to the project.
The site has open ditches in the right-of-way or private road right-of-way
There are no catch basins on or near the site.
Catch basins on the site or immediately off site in the right-of-way are shown on the SWPPP Site Plan. Storm drain
inlet protection shall be installed. lf this option is selected check the BMPS you will use below:
C220 Storm Drain Inlet Protection
page 3 of 6
tr C2o6Levelspreader fl
Worksheet 81
Construction Protection: Mediu.m and Large Projects
(SWPPP: Stormwater Pollution Prevention PIa n )
i'[l
Element 8: Stabilize Channels and Outlets
The goal of this element is to design, construct, and stabilize on-site conveyance channels to prevent erosion
from entering existing stormwater outfalls and conveyance systems.
one of the three stotements applicoble to the project.
Construction will occur during the dry weather. No storm drainage channels or ditches shall be constructed either
temporary or permanent.
There are no existing or proposed stormwater conveyance channels on the project site.
A wattle shall be placed at the end of the swale to prevent erosion at the outlet of the swale. lf this option is
selected check the BMPS you will use below:
n Czoz Channel Linins n Czoz Check Dams
-
n Czog Outlet Protection n Czrs Wattles
Element 9: Control Pollutants
The goal of this element is to design, install, implement and maintain BMPs to minimize the discharge of
pollutants from material storage areas, fuel handling, equipment cleaning, management of waste materials, etc.
This element does not opply to my project becouse (circle ony thot opply - lf any box is unchecked this element applies.
There will be no concrete work,
ffin"r" willbe no sawcutting work,
f,rn"r"will be no hazardous materials on-site,
ffin"r" will be no fertilizer or pesticide application,
l-l rf,"r" will be no heavy equipment associated with this project,
ffiffr"r" will be no pressure washing, equipment maintenance or dewatering
lf one or more of the checkboxes above are unchecked. Any and all pollutants, chemicals, Iiquid products and other
materials that have the potential to pose a threat to human health or the environment will be covered, contained, and
protected from vandalism. All such products shall be kept under cover in a secure location on-site. Concrete handling
shall follow BMP C151 C154. lf this option is selected check the BMPS you will use below:
lV Ctst Concrete Handlins
--
C152 Sawcuttins and Surfacins
l-.l CtSg Material Deliverv. Storase. and Containment
-
C154 Concrete Washout Area
tr
tr
Worksheet 81
Construction Pro_tection: Medium and Large Prciects
(SWPPP: Stormwater Pollution Prevention Plan) v
Element 10: Control De-watering
The goal of this element is to handle turbid or contaminated water from dewatering (removal of water)
sepa rately from stormwater.
Select one of the two stotements applicoble to the praject.f,r No dewatering of the site is anticipated
Dewatering of the site is anticipated. lf this option is selected check the BMPS you
willuse below:
C203 Water Bars n CZllVesetated Filtration V CZOdLevel Soreader
Element L1: Maintain Best Management Practices
The goal of this element is to maintain and repair all temporary and permanent erosion and sediment control
BMPs to assure continued performance.
Describe the steps you will take:
r-zrt Besl Management Practices or BMPs shall be inspected and maintained during construction and removed within
V) 30 days after the County lnspector or determines that the site is stabilized, provided that they may be removed
when they are no longer needed.
Element 12: Manage the Project
The goal of this element is to ensure that the owner and those performing the site work comply with the
SWPPP and properly coordinate to ensure that all BMPs are deployed at the proper time to achieve full
compliance with county regulations throughout the project.
The SWPPP will be implemented at all times. lf applicable to the project, erosion control BMPs will be
implemented in the following sequence:
1. Mark clearing limits
2. lnstall stabilized construction entrance
3. lnstall protection for existing drainage systems and permanent drain inlets
4. Establish staging areas for storage and handling polluted material and BMps
5. lnstall sediment control BMPs
6. Grade and install stabilization measures for disturbed areas
7. Maintain BMPs untilsite stabilization, at which time they may be removed
page 5 of 6
Worksheet 81
Construction Pro_tection: Mediu.m and Large Proiects
(SWPPP: Stormwater Pollution Prevention Plan)
Element 13: Protect Low lmpact Development BMPs
The goal of this element is to protect permanent stormwater management BMPs from siltation and compaction
during construction. The permanent stormwater management BMPs used for runoff from roofs and other hard
surfaces include: frl$i:pS@, roof downspout full infiltration or dispersion systems, perforated stubout
connections, rainffi6s3ioretention systems, permeable pavement, sheetflow dispersion, and concentrated
flow dispersion.
Methods that will be used to protect permanent stormwater management BMPs include:
Sequencing the construction in a fashion to installthese permanent BMPs at the latter part of the
construction grading operations,
[_] Excluding equipment from the BMPs and the associated areas,
Using the erosion and sedimentation control BMPs listed below to protect facilities such as drywells,
raingardens, permeable pavement, or bioretention from accumulating sediment during construction and
before site restoration. lf this option is selected check the BMPS you will use below:
C102 Buffer Zone Cl03 Hish Visibilitv Fence
C234Yesetated Strip
Other
C233 Silt Fence
Applicant or Representative Signature
n Czlt grush garrier
IWorksheet C
What's the best option for your site?
system on or an acent
-r.
Minimum Requirement #5 (On-Site Stormwater Management)
The following tables summarize the criteria that can be used to justiff why you cannot use various stormwater
management best management practices (BMPs) for consideration for Minimum Requirement #5. This information is also
included under the detailed descriptions of each BMP in the Department of Ecology's Stormwater Management Manual for
Western \A/hshington (SVlTvlM\ /W 120141). Where any inconsistencies or lack of clarity exists, the requirements in the main
text of the S\AIII/IMVW shall be applied.
HOW TO USE:
Evaluate the feasibility of the BMPs in priority order based on Worksheet Al page 5 (List #1) or 6 (List #3) or
Worksheet L for Large Projects (List #2). Only one criterion needs to be selected for a BMP before evaluating the
next BMP on the list.
None of the above boxes are checked. This is the BMP that must be used for lawn and landscaped areas. On
Worksheet A1, indicate that this will be the BMP used. CONTINUE to complete the fonn for other surface types
applicable to the project. lf none, STOP.
X
ut
lnfiltration
BMP T5.1OA,
S\MtIM\MA/Volume
lll, Section 3.1.1
List#1, #2
and #3
There is an
lot (mound, sand filter pressure distribution, Glendon, aerobic
treatment unit). Therefore, there is not at least 3 feet or
more of permeable soil from the proposed final grade to the
seasonal high groundwater table or other impermeable layer.
There is not at least 1 foot or more of permeable soil from
the proposed bottom of the infiltration system to the seasonal
high groundwater table or other impermeable layer.
Lawn and Landscaped Areas
BMP and
Applicable
Lists
Reason why the BMP will not work on site.Additional Comments
lf needed
Post-construction
Soil Quality
and Depth
(BMPT5.13
SVI/MMIA/VI/Volume V
Sec{ion 5.3)
List#1,#2and#3
Lawn and landscape area is on till slopes greater than 33
percent.
Siting and design criteria cannot be achieved on site
Roofs
BMP and
Applicable
Lists
Reason why the BMP will not work on site.Additional Comments
lf needed
Full Dispersion
BMP T5.30,
S\/MMVM/VolumeV
Section 5.3
List #1 and#2
A 65 to 10 ratio of forested or native vegetation area to
impervious area cannot be achieved.
A minimum forested or native vegetation flowpath length of
100 feet (25 feet for sheet flow from a non-native pervious
surface) and protected by easement cannot be achieved.
Siting and design criteria cannot be achieved on site.
K None of the above boxes are checked. This is the BMP that must be used for roofs. On WorksheetAl, indicate that
this will be the BMP used. CONTINUE to complete the form for other surface types applicable to the pQect. lf none,
STOP.
I
f
Ia
1
tr
tr
Worksheet C
What's the best option for your site?
BMP and
Applicable
Lists
Reason why the BMP will not work on site.Additional Comments
lf needed
FullDispersion
BMP T5.30
SVVTVIMWWVo|ume
V Section 5.3
List #1 and#2
A 65 to 10 ratio of forested or native vegetation area to
impervious area cannot be achieved.
A minimum forested or native vegetation flowpath length of
100 feet (25 feet for sheet flow from a non-native pervious
surface) cannot be achieved.
Siting and design criteria cannot be achieved on site.
K None of the above boxes are checked. This is the BMP that must be used for hard surfaces. On WorksheetAl,
indicate that this will be the BMP used. CONTINUE to complete the form for other surface types applicable to the
project. lf none, STOP.
Permeable
Pavement
BMP T5.15,
S\MiM\ttlWVolume
V Section 5.3
List #1 and#2
* Note that
Raingardens
may be used
in lieu of
permeable
pavement if
subject to
List #1.
Citation of any of the following infeasibility criteria must be
based on an evaluation of site-specific conditions and a written
recommendation from an appropriate licensed professional (e g ,
engineer, geologist, hydrogeologist):
Where professional geotechnical evaluation recommends
infiltration not be used due to reasonable concerns about
erosion, slope failure, or downgradient flooding.
tr \Mthin an area whose ground water drains into an erosion
hazard, or landslide hazard area.
\Nhere infittrating and ponded water below the new permeable
pavement area would compromise adjacent impervious
pavements.
Where infiltrating water below a new permeable pavement
area would threaten existing below grade basements.
Where infiltrating water would threaten shoreline structures
such as bulkheads.
Down slope of steep, erosion prone areas that are likely to
deliver sediment to the area of pervious pavement.
\Mrere fill soils are used that can become unstable when
saturated.
Excessively steep slopes where water within the aggregate
base layer or at the subgrade surface cannot be controlled
by detention structures and may cause erosion and structural
failure, or where surface runofi velocities may preclude
adequate infiltration at the pavement surface.
6
Other Hard Surfaces
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