HomeMy WebLinkAboutUpdated Stormwater Calculation Sheet 1.8.23DEPARTMENT OF COMMUNITY DEYELOPMENT
621 Sheddan Street, Port Townsend, rJVA 98368
Tel: 360.379.4450 | Fax: 36A 379.4451
Web: www.ctr.iefferson.wa.us/communiwdcvelooment
E mail dcdCDco.iefferson.wa.us Scan the QR
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the digitalform
STORMWATER CALCULATION WORKSHEET
PARCEL #OO t - OCrl - OOS pRorEcr/AppucANrNAME: 5*r-&
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
required.
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.
Ndtive 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.
sqlftSize of parcel in square t"et ?+5, tl X-{
Sizeof pur""t B. b2u"r",
@
@
sq/ft
sq/ft
I
0 sqlft
cutOFilq(cu/yd)
Well. utilities, etc.LLO
Construction site for structures
Driveway, parking, roads. etc.
Lawn. Iandscaping. etc.
Drainfield, septic tank, etc.
lndicate Total Volumes of Proposed:
(lncludes BlVlP-rcj3 f iil Vsl-rlr_t_e)
Answer the following two questions related to
conversion of native vegetation:
Does the project convert 2/, acres or more of
native vegetation to pasture?
Circle: Yes
Does the project convert T, acres or more of
native vegetation to lawn or iandscaped areas?
Circle: Yes
sq/ft
sdft
sq/ft
sqrft
Tem porary construction area
Total Land Disturbance
Calculate the total area to be cleared, graded, filled,
excavated, andlor compacted for proposed development
project. lnclude in this calculation the area to be cleared for:
stormwater €lc worksheet QR ode - REV. 5/31/2019 page 1 of2
LAND DISTURBING ACTIVITY. CONVERSION OF NATIVE VEGETATION. AND VOLUME OF CUTIFILL
Other compacted surface. etc _
Jan 10 2023
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 NE\IY + TOTAL EXISTING"*This amount will be used to check total lot coverage.
Tota.l Et<isting sqrft
Other
_sq/ft
NEW
Structures (all roof area)
Sidewalks
Patios
Solid Decks
(without infi ltration below)
Driveway, parking, roads, etc
Other
ExrsrNG V tA
Structures (all roof area)
Sidewalks
Patios
Solid Decks sq/ft
(without infi ltration below)
Driveway, parking, roads, etc _sq/ft
Divide the total existinq
impervious surface above by the
size of the parcel and converi to
a percentage.o/o
DEVELOPMENT v. REDEVELOPMENT
Does the site have > 35% or more
existino impervious surface?->.)
t
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 A1
and 81, a stormwater site plan and a construction stormwater pollution prevention site plan (See Reference A1A and B1A for
guidance).).
- "Large" projects-those that must meet all 9 Minimum Requirements- must submit Worksheet A1 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
Development 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 knowledge and consent of all owners
nelnrsrrutmvE steruntunr)
d
of the
stormwater Glc rc.ksheet QR ode - REV. 5/31,2019 page 2 ot 2
sq/ftILO *qt
-sq/ft
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