HomeMy WebLinkAboutStampedLog Item 7 Stormwater PlanEco OgeLicaI
Land Services
December 20, 2018 Ile"
Jefferson County Department of Development
�� Q 2NAttn: David Wayne Johnson, Associate Planner
621 Sheridan Street JEFFERSON COUNTX
Port Townsend, Washington 98368
Re: Site Address: 3020 Dosewallips Road, Brinnon, WA 98320; Case #: MLA18-00105
Dear David,
This letter is intended to provide a brief narrative of best management practices related to stormwater
pollution prevention. It accompanies the attached stormwater calculation worksheet.
Minimize Disturbed Area and Protect Natural Features and Soil
Excavated soil will be stockpiled as indicated on the stormwater map and protected from rainfall for the
duration of the project. Temporary stabilization such as plastic sheeting and silt fencing will be applied to the
stockpile once it is excavated, as needed.
Control Stormwater Flowing onto and through the Project
The project will take place inside of a few days (2 to 4 days) and will be performed during dry weather to
minimize the amount of stormwater entering the project. A silt fence will be installed around the perimeter of
the work site.
Stabilize Soils
Temporary: The soil which will be temporarily stockpiled will only be in place for the duration of the project (2
to 4 days). The stockpile will be protected from potential rainfall with plastic sheeting as needed until it is
hauled outside the project area. Dust control will not likely be needed due to the duration of the project.
Permanent: Exposed soils left by installation of the pipe will be covered with a woody mulch immediately upon
completion of construction and replanted shortly afterwards.
Protect Slopes
Slope protection- will involve following any and all recommendations given by the project geotechnical
engineer.
Establish Perimeter Controls and Sediment Barriers
Silt fencing will be installed around the limits of the project area to contain any sediment. It will be installed a
minimum of 6 inches into the substrate and supported to prevent overtopping. However, because the project
will be conducted over a short period of time, significant rainfall is severely unlikely.
1157 • 3rd Avenue Suite 220A • Longview, Washington 98632 • Tel (360) 578-1371 • Fax (360) 414-9305
Rocky Brook Hydroelectric
December 20, 2018
Page 2
Retain Sediment On-site
Due the brief nature of the project, sediment build-up is unlikely to occur, however, perimeter silt fencing
should serve to trap any sediment that may runoff during any rainfall events. Sediments will be stockpiled
along with spoils and taken offsite.
Establish Stabilized Construction Exits
The access road onsite has been in place for over 30 years and is highly compacted. If an excavator is needed
to perform the work, it will only make one trip in and one trip out of the construction area. If needed, the
access road will be'repaired and supplemented with crushed rock.
If there are any questions about the materials presented, I can be reached via email (lauraw@eco-land.com)
or at the office (360) 674-7186.
Sincerely,
Laura H. Westervelt
Professional Biologist
Attachments
Stormwater Calculation Worksheet
DEPARTMENT OF COMMIJNITY DEVELO
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'I'd: 300.37).4430 1 Hx: '360.3",1).4451 P,1119'
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MLA # PRCJ ECT/APPLI CANT NAME:
JEFFERSON COUNTY DW
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.
PARCI=L SIZE (I.E�SITE)
Size of parcel 10.8 acres An acre contains 43,560 square feet. Multiply the acreage by this figure.
Size of parcel in square feet 470,448 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 on plant species, other than noxious weeds, that are indigenous to the coastal region of
the Pacific Northwest and 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.
ISTURBING ACTIVITY CONVERSION OF NATIVE VEGETATION AND VOLUME OF CUTIFILL
total area to be cleared, graded, filled,
F
Answer the following two questions related to
d/or compacted for proposed development
conversion of native vegetation:
de in this calculation the area to be cleared
for:
0
Does the project convert '/4 acres or more of
Construction site for structures
sq/ft
native vegetation to lawn or landscaped areas?
Drainfield, septic tank, etc. 0
sq/ft
Circle: Yes No
Well, utilities, etc. 100
sq/ft
Does the project convert 2'/2 acres or more of
0
native vegetation to pasture?
Driveway, parking, roads, etc.
scilfl
Circle: Yes No
Lawn, landscaping, etc. 0
sq/ft
Other compacted surface, etc. 0 .�
sq/ft
Indicate Total Volumes of Proposed:
Total Land Disturbance 100
sgift
Cut 0 Fill 0 (culyd)
impervious surface is a hard surface that either prevents or retards the entry of water into the soil mantle 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.
stormwater talc worksheet — REV. 1 012012 01 4
STOR WATE _ g,6LQULATl0tI5 — IMPS VIOU QB ACE
NEW EXISTING
1200
Structures (all roof area) 0 sq/ft Structures (all roof area) sq/ft
Sidewalks 0 sq/R Sidewalks 0 sq/ft
Patios 0 sglft
Solid Decks 0 sgfft
(without infiltration below)
Driveway, parking, roads, etc 0 sq/ft
Other 0 sq/ft
Total New 0 sq/ft
TOTAL NEW + TOTAL EXISTING" 8200
Patios 0 sq/ft
Solid Decks 0 sq/ft
(without infiltration below)
Driveway, parking, roads, etc 7000 sq/ft
Other sq/ft
Total Existing 8200 sglft
'This amount will be used to check total lot coverage.
The following questions will help determine whether the proposed project is considered development or redevelopment.
DEVELOPMENT v. REDEVELOPMENT
.71
Divide the total existing1
impervious surface above by the size of the parcel and convert to a percentage: %
Does the site have 35% or more of existin impervious surface? Circle: Yes El No 0
FURTHER INSTRUCTIONS. If the answer is yes, the proposal is considered redevelopment and the attached Figure 2 should be used
to determine the applicable Minimum Requirements. If the answer is no, the proposal is considered new development and the
attached Figure 1 should be used. At this juncture, the applicant should refer to the applicable Flow Chart to determine the
Minimum Requirements for stormwater management. DCD staff will help verify the classification of the project and the application
requirements.
For proponents of "small" projects who must comply only with Minimum Requirement #2—Construction Stormwater Pollution
Prevention --an additional submittal is not required. 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 (SWPP) Best Management Practices (BMPs) Packet. Proponents of "medium"
projects—those that must meet only Minimum Requirements #1 through 05 --and for "large" projects—those that must meet all 10
Minimum Requirements—are required to submit a Stormwater Site Plan. DCD has prepared a submittal template of a Stormwater
Site Plan, principally for rural residential projects. Complete the template in the Stormwater Site Plan Instructions and Submittal
Template or prepare a Stormwater Site Plan using the step-by-step guidance in the Stormwater Management Manual.
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.
(DATE)
(LAN& EROR At TKORIZW REPRESENTATIVE SIGNATUREi
FOR OFFICE USE ONLY
SMALL_ MEDIUM -
LARGE REDEVELOPMENT- stormwater Site Plan: Yes
2
slormwaler talc worksheet — REV. 10/2012014
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