HomeMy WebLinkAboutSTORMWATER WORKSHEETDEPARTMENT OF COMMUNITY DEVELOPMENT
621 Sheridan Street, Port'fownsend, \VA 98368
Tel: 360.379.4450 1 Fax: 360.379.4451
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STORMWATER CALCULATION WORKSHEET
PARCEL# 601071001 PROJECT/APPLICANTNAME:
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.
PARCEL SIZE (I.E., SITEI
Size of parcel 10.94 acres An acre contains 43,560 square feet. Multiply the acreage by this figure.
Size of parcel in square feet 476546.4 sq/ft
Land -disturbing activity 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.
Native vegetation 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.
LAND DISTURBING ACTIVITY CONVERSION OF NATIVE VEGETATION AND VOLUME OF CUTIFILL
Calculate the total area to be cleared, graded, filled,
Answer the following two questions related to
excavated, and/or compacted for proposed development
conversion of native vegetation:
project. Include in this calculation the area to be cleared for:
Does the project convert % acres or more of
Construction site for structures N/A
sq/ft
native vegetation to lawn or landscaped areas?
Drainfield, septic tank, etc. N/A _
sq/ft
Circle: Yes (N-6)
Well, utilities, etc. N/A
sq/ft
Does the project convert 2'/2 acres or more of
native vegetation to pasture?
Driveway, parking, roads, etc. N/A
sq/ft
Circle: Yes No
Lawn, landscaping, etc. NIA
sq/ft
Other compacted surface, etc. 564
sq/ft
Indicate Total Volumes of Proposed:
(Includes BMI' T5.13 Fill Volume)
Temporary construction area N/A
sq/ft
Total Land Disturbance
sq/ft
Cut Fill (cu/yd)
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STORMWATER CALCULATIONS — IMPERVIOUS SURFACE
Impervious 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.
NEW
Structures (all roof area) 0 sq/ft
Sidewalks 0 sq/ft
Patios
0 sq/ft
Solid Decks 0 sq/ft
(without infiltration below)
Driveway, parking, roads, etc 0 sq/ft
Other 336 sq/ft
Total New 336 sci/ft
TOTAL NEW + TOTAL EXISTING" 83,107
EXISTING
Structures (all roof area) 21,900 sq/ft
Sidewalks 0 sq/ft
Patios
sq/ft
Solid Decks 0 sq/ft
(without infiltration below)
Driveway, parking, roads, etc 59,771 sq/ft
Other 1.100 sglft
Total Existing 82,771 sq/ft
sci/ft "This amount will be used to check total lot coverage.
DEVELOPMENT v. REDEVELOPMENT
Divide the total exisfrn ♦ Does the site have > 35% or more
impervious surface above by the existing impervious surface?
size of the parcel and convert to 1
a percentage. 17_37 % ■
The proposal is considered new development. Answer
yes questions in Figure 2.4.1 Flow Chart for New
Development to determine project size (next page).
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 up 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 Al
and 131, a stormwater site plan and a construction stormwater pollution prevention site plan (See Reference A1A and 131A for
guidance).).
— "Large" projects —those that must meet all 9 Minimum Requirements— must submit Worksheet Al and 131, 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.
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
of the affected property.
(LANDOWNER OR AUTHORIZED REPRESENTATIVE SIGNATURE) (DATE)
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