HomeMy WebLinkAboutBLD2018-00077 - 05 STORMWATERoo
DEPARTMENT OF COMMI-INITY D
621 Sheridan Street, Port Townsend, WA 98368
Tel: 360.379.4450 | Fax: 360.379.4451
Web: urwrv.co.iefferson.wa.tr^s /communiqdevelopment
E-mail: dcd(O.co.iefferson.wa.us
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STORMWATER CALCUI.ATION WORKSHEET
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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.
Land-disturbing octivity 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 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.
lmperuious 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
increasedrateofflowfromtheflowpresentundernatural conditionspriortodevelopment. Commonimpervioussurfacesinclude,
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 orothersurfaceswhich similarly impedethe natural infiltration of stormwater.
rurl #eRotecr/aRRlrcam ruaue:
PARCEL SIZE (I.E.. SITE)
An acre contains 43,560 square feet. Multiply the acreage by this figure.
sq/ftSize of parcel in sq uarereet 2215+b
Sizeof oarcet 5.086 ^"r",
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sq/ft
sq/ft
sq/ft
Well, utilities, etc.4a; gl;'w,
Lawn, landscaping, etc.5ooo
Other compacted surface, etc.[00 o
Drainfield, septic tank, etc.o*'s1;
Total Land Disturbance lb 0oo
lndicate Total Volumes of Proposed:
cut 3c;D p;11 30 O (cu/yd)
Answer the following two questions related to
conversion of native vegetation:
Does the project convert 7, acres or more of
native vegetation to lawn or landscaped areas?
Circle: Yes
Does the project convert 2/, acres or more of
native vegetation to pasture?
Circle: Yes
Calculate the total area to be cleared, graded, filled,
excavated, and/or compacted for proposed development
project. lnclude in this calculation the area to be cleared for:
Construction site for structures 5 OO O
Driveway, parking, roads, etc. SOOO
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sq/ft
sq/ft
sq/ft
stomater €lc worksheet - REV. lODOnU4
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FEB 2 2 zug ,! ,!,
LAND DISTURBING ACTIVITY. CONVERSION OF NATIVE VEGETATION. AND VOLUME OF CUT/FILL
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STORMWATER CALULATIONS - IMPERVIOUS SURFACE
116O ,crftTotal New Total Existing
TOTAL NEW + TOTAL EXISTING*'This amount will be used to check total lot coverage.
AU 5
NEW
Structures (all roof area)iToS
Sooo 10 05
Sidewalks
Patios
Solid Decks
(without infi ltration below)
EXISTING
structures (altroof area) 01 5 4 *n
Sidewalks
Patios
Solid Decks
(without infi ltration below)
Driveway, parking, roads, etc
Other
Driveway, parking, roads, etc
Other
90 o ,r,o
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The following questions will help determine whether the proposed project is considered development or redevelopment.
FURTHER INSTRUCTIONS: lf the answer is yes, the proposal is considered redevelopment and the attached Figure 2 should be used
to determine the applicable Minimum Requirements. lf 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 #5-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 lnstructions and Submittal
Template or prepare a Stormwater Site Plan using the step-by-step guidance in the Stormwoter Monogement Monuol.
APPLICANT SIGNATURE
2
DEVELOPMENT v. REDEVELOPMENT
Divide the total g4!g!!4g impervious surface above by the size of the parcel and convert to a percentag ", ' 03 o1o
Does the site have 35% or more of existino impervious surface?ENoCircle:Yes
By signing the Stormwater Calculation Worksheet, I as the applicant/owner attest that the information provided herein is true and correct to the
srerarune)
certify that this application is being made with the full knowledge and consent of all owners of the affectedknowledge. Ibest of my
property.
stomatsr elc worksh&t - REV. 1ODODO14
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DEPARTMENT OF COMMUNITY DEVEL
621 Sheridan Street, Port Townsend, WA 98368
Tel: 360.379.4450 | Fax: 360.379.4451
Web: www. co. iefferson.wa. us/comm unitvdevelop ment
E-mail : dcd@co. iefferson.wa.us
STORMWATER SITE PI.AN SUBMITTAL
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uu#pnotect/npplrcANT NAME :
Please answer all of the following questions to the best of your ability. Where the question calls for depiction on a site map, the
applicant may choose to either incorporate the elements into the general plot plan for the Master Land Use Application or to submit a
separate stormwater site plan map.
1
Project Overview
Describe the proposed developed conditions of the site. lndicate position and relative size of proposed improvements on the
site
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3. Describe the areas on thenative
soils. lndicate soil on the site4. Describe the
5 theDescribe site e.d ofbehaviorexisting onwater site-abovethe andbelow,on(i.hydrology rainage;the lndicateground).
existi stormwater andto thefrom onsite sitethengdrainage onbasins themap.separateDepict ifsitedrainagemap,
indicateand of each.
of noise use orDescribeexcessthe
Describe significant geographic features and critical areas (i.e., environmentally sensitive areas such as wetlands, streams,7
etc on the site. lndicate location on the site
stomwater site plan template - rev. 4[/2016
Existing Conditions Summary
2. Dqscribe the existing topography. ln contours on the site map.
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8. Describe the general vicinity of the site, including adjacent land uses and structures, utilities, roads, and sensitive/critical areas
etc
This portion of the Stormwater Site Plan consists of the selection and installation of the appropriate stormwater control BMPs
and facilities to remain in place after construction of the proiect is completed.
"Medium' size projects are required to have the totals calculated of all impervious surfaces, pollutiongenerating impervious
surfaces, and poliutiongenerating pervious surfaces to verify that the thresholds for treatment facilities and flow control
facilities are not exceeded.
I d B PM T5.30whetherlndicatewillstormwaterfulbei.e.,theDescribe site AS ly ispersed perhydrologyproposeddeveloped
for orsite threshold d areasofflowstormwaterwillcontrolutilizedbetheinor.if what specific ischargenot,typesManual)
fromfacilities facilities.theseLocate onfacilities sitethe and differentiate proposed existingsitetheplan
Permanent Stormwater Control Plan
lf the project requires the use of stormwater treatment facilities, describe the types of stormwater treatment facilities proposed
for use on the site. Locate these facilities on the site plan and dffierentiate proposed facilities from existing facilities. [this is
"large" projects or projects that involve the potential for dispersion of contaminants.l
10.
11. Describe the performance goals and standards applicable to the proiect.
12. Describe the flow control system.
13. Describe the quality system
6stomwater site plan template - rev. 4rl2016
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14. Describe the conveyance system analysis and design
15. Describe the source of fill material, physical characteristics of fill material, and deposition of excess material
16.Proposed methods of placement and compaction consistent with the applicable standards on Appendix Chapter 33 of the
Uniform Building Code.
17. Describe the proposed surfacing material.
18. Describe methods for restoration of the site.
'19. An Operation and Maintenance Manual is required for each flow control and treatment facility. [his is normally required for
"large"
here.
projects only and only those for which facilities are required to control flow or treat runoff.l lf included, list the Manuals
20. List here and include any special reports or studies conducted to prepare the Stormwater Site Plan.
21 List other necessary permits and approvals as required by other regulatory agencies. lf those permits or approvals include
conditions that affect the drainage plan or contain more restrictive drainage-related requirements, describe those conditions or
restrictions here.
7stomwater site plm teflplate - rev. 4nl2016
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CoNSTRUCTTON STORMWATER POLLUTION PREVENTION PLAN (SWPPP)
The Construction SWPPP addresses sediment and erosion control during construction. The BMPs indicated by the applicant in the
template that follows must be installed on the ground during all construction phases of the project. The proponent is responsible for
preventing sediment and erosion impacts to environmentally sensitive areas and off-site areas. Consult the Construction Stormwater
Pollution Prevention (SWPP) Best Management Praclices (BMPs) Packet for guidance, particularly with rural residential
development.
SECTION I - CONSTRUCTION SWPPP NARRATIVE
1 Construction Stormwater Pollution Plan Elements. Describe how each of the Construction SWPPP elements has been or
will be addressed. ldentify the type and location of BMPs used to satisfy the required element. lf an element is not applicable to
the proposal, justify in writing. Detailed descriptions of the 13 Elements are found at Volume ll Section 3.3.3 of the Manual
(beginning on page &11).
13 Required Elements - Construction SWPPP
1. Mark Limits.
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2. Establish Construction Access.
3. Control Flow Rates
4. lnstall Sediment Controls.
,
5. Stabilize Soils.or
6. Protect
7. Protect Drain lnlets.
stomwats site dan template - rev. 4fl2016
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13 Required Elements - Construction SWPPP (continued)
8. Stabilize Channels and Outlets.
Pollutants.
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10. Control (the act of away ftom an active ,).
11. Maintain Best Practices ).
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13. Protect (('BMP'S
Adjacent Areas.
a. Description of the adjacent areas that may be affected by site disturbance (e.g., streams, lakes, wetlands, residential
areas, roads).
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b. Description of the downstream drainage path leading ftom the site to the receiving body of water
2.
yards).
S<
(minimum distance of 400
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Environmentally Sensitive Areas.
a. Description of environmentally sensitive areas that are on or adjacent to the site.
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stmwater site dan template - rev. 4nl2o16
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b. Description of special requirements for working in or near environmentally sensitive areas.
4 Erosion Problem Areas. Description of potential erosion problems on site in the context of the characteristics of the on-site
soils (e.9., erodibility, settleability, pelmeability, depth, texture, soil structure).
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5.Construction Phasing.
a. Constructionsequence
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b. Construction phasing (if proposed)
6. Gonstruction Schedule. Wet season is October 1 through April 30 (page 2-20 of the Manual).
construction
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ll.Wet Season Construction Activities.
a. Proposed wet season construction activities.
b. Proposed wet season construction activities for environmentally sensitive areas.
7. Financial/Ownership Responsibilities
a. ldentiff the responsible for tf,linitiation of bonds and/or other financial securities.
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b. Describe bonds and/or other evidence of financial responsibility for liability associated with erosion and sedimentation
impacts.
8. Engineering Calculations. Provide Design Calculations on a separate sheet for the following, if applicable.
a.
b.
c.
d.
Sediment PondVTraps.
Diversions.
Waterways.
Runoff/Stormwater Detention Calculations
t^5.
sttrmwater site plan template - rev. 4nl2016 '10
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SECTION II- EROSION AND SEDIMENT CONTROL PLAN
Sediment and erosion controlmeasures may be depicted on the master land use application plot plan, a stormwater s1e plan, and/or a
separate Construction SWPPP site plan. This is a checklist to ensure that the following are depicied on a site plan:
1 General.
a. Vicinity Map
b. Jefferson County Approval Block
c. Erosion and Sediment Control Notes
2. Site Plan.
a. Legal description of subject property.
b. North anow.
c. lndicate boundaries of existing vegetation (e.g., tree lines, pasture areas, etc.).
d. ldentify and label areas of potential erosion problems.
e. ldentify FEMA base flood boundaries and Shoreline Management boundaries (if applicable).f. Show existing and proposed contours.
s. lndicate drainage basins and direction of flow for individual drainage areas.
h. Label final grade contours and identifi developed condition drainage basins.
i. Delineate areas that are to be cleared and graded.
j. Show all cut and fill slopes indicating top and bottom of slope catch lines.
3. Conveyance Systems.
a. Designate locations for swales, interceptor trenches, or ditches.b. Show all temporary and permanent drainage pipes, ditches, or cut-off trenches required for erosion & sediment control.c. Provide minimum slope and cover for all temporary pipes or call out pipe inverts.d. Shows grades, dimensions, and direction of flow in all ditches, swales, culverts and pipes.
e. Provide details for bypassing off-site runoff around disturbed areas.f. lndicate locations and outlets of any dewatering systems.
4. Location of Detention Best Management Practices (BMPs). ldentifi location of detention BMps.
5. Erosion and Sediment Control Facilities.
a. Show the locations of sediment trap(s), pond(s), pipes and structures.
b. Dimension pond berm widths and inside and outside pond slopes.
c. lndicate the trap/pond storage required and the depth, length, and width dimensions.
d. Provide typical section views through pond and outlet structure.
e. Provide typical details of gravel cone and standpipe, and/or other filtering devices.
f. Detail stabilization techniques for oufleUinlet.
g. Detail controUrestrictor device location and details.
h. Speci! mulch and/or recommended cover of berms and slopes.
i. Provide rock specifications and detail for rock check dam(s), if applicable.j. Specify spacing for rock check dams as required.
k. Provide front and side sections of typical rock check dams.
L lndicate the locations and provide details and specifications for silt fabric.
m. Locate the construction entrance and provide a detail.
t)Detailed Drawings. Any structural practices used that are not referenced in the Ecology Manual should be explained and
illustrated with detailed drawings.
Other Pollutant BMPs.
sediment (e.9., concrete
lndicate on the site plan the locations of BMPs to be used for the control of pollutants other than
wash water).
7
8.Monitoring Locations. lndicate on the
the construction site. Sampling stations
site plan the water quality sampling locations to be used for monitoring water quality on
should be located upstream and downstream of the project site.
stomwats site plan template - rev. 4fll2016 't1
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Stormwater Site Plan Changes
lf the designer wishes to make changes or revisions to the originally approved Stormwater Site Plan, the proposed revisions shall be
submittedlo DCD prior to construction. The submittal shall include substitute pages that include all proposed changes, revised
drawings showing any structural changes, and any other supporting information that explains and supports the reason for the change.
Final Corrected Plan Submittal
lf the project included construction of conveyance systems, treatment facilities, flow control facilities, or structural source control BMPs
(not standard on-site stormwater management BMPs), the applicant shall submit a final conected plan ("as-builts") when the project is
completed. These should be engineering drawings (stamped by a licensed civil engineer) that accurately represent the project as
constructed.
APPLICANT SIGNATURE
THIS SPACE MAY BE USED FOR ADDITIONAL NOTES, IF NEEDED:
OR
By signing the Construction SWPPP worksheet, I as the applicanUowner attest that the information provided herein is true and
conect to the best of my knowledge. I also certify that this application is being made with the full knowledge and consent of all
REPRESENTATIVE SIGNA
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owners of the affected
stomwater site dan template - rev. 41il2016 12