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HomeMy WebLinkAboutBLD2015-00103 - 05 STORMWATER • DRAINAGE & EROSION CONTROL PLAN FOR MATSUNAMI SINGLE FAMILY RESIDENCE • ANN MATSUNAMI 1650 LILIHA ST. HONOLULU,HAWAII 96817 — IJ 1 !r .! MAR 31 2015 PROJECT LOCATION: U II 190 BEE MILL RD P — ------- � BRINNON,WA JELFERS(P COUNTY } r‘ DT OF COMMUNITY DEVELOPMENT PARCEL No: 963-900-023 APPROVED Prepared for: JEFFERSON COUNTY STORMWATER PLAN 1820 JEFFERSON ST PORT TOWNSEND,WASHINGTON 98368 APR - 5 2014 IUNTY YELOPMENTT ���„,�. •� r Prepared by: SI APURE: Jr!'4 ZENOVIC&ASSOCIATES,INCORPORATED 301 EAST 6TH STREET,SUITE#1 / PORT ANGELES,WASHINGTON 98362 Project No. 14288 March 17,2015 • • DRAINAGE& EROSION CONTROL PLAN & PROJECT OVERVIEW A single family residence (approx. 1,110 sq. ft. footprint)will be constructed in lot 17 of Jackson Cove Park, address 190 Bee Mill Road, Jefferson County parcel number 963- 900-023;the lot is 0.274 acres in size. There is an existing home, garage, asphalt driveway, and septic system on site. Total impervious area on the site is approximately 4,408 sq. ft. with approximately 575 sq. ft. of decking surrounding the residence. Existing impervious surfaces cover approximately 36.9% of the parcel. The existing home will be demolished and removed, along with a portion of the existing asphalt driveway/parking to construct and install a new septic system. An existing green house and covered platform have been removed. Upon completion of the proposed development there will be a total of 3,902 sq. ft. of impervious surfacing (asphalt, garage roof,proposed roof) and 250 sq. ft. of exposed decking. An anticipated 144 sq. ft. of concrete will be poured surrounding a hot tub. The construction would result in the removal of approximately 506 sq. ft. of impervious surfacing. The resulting percent impervious area would be reduced to 32.7%. Based on the Stormwater Calculation Worksheet(see attached)for Jefferson County,the project is classified as a"small"project/redevelopment. With this classification only Minimum Requirement#2 is applicable,which entails considering the twelve (12) Construction Stormwater Pollution Prevention (SWPP) Best Management Practices during construction. The information packet is attached. Detailed erosion and sediment control practices, procedures, and timing are outlined in the WESTECH COMPANY Mitigation and Habitat Management Plan (MHMP), location of BMP's can be found on the provided site plan. Downspout splash blocks (minimum 3) should be constructed to promote dispersion and infiltration of roof runoff. Based on the findings in the MHMP the soils in the proposed construction area vary from Grove very gravelly sand(GrC) and Olete-Hoodsport Complex (OpD). The first 20-30 inches of both soils are well draining, utilizing splash blocks will allow for onsite retention/infiltration and help reduce erosion and rifling to the east. Construction activity will include the demolition and removal of existing asphalt and home, excavation and grading for the proposed S.F.R., construction and installation of the proposed septic system (designed by others), excavation and installation of new utilities, construction of the proposed home, construction and installation of stormwater structures(splash blocks), Construction of stairs/pathway to the tidal flats, delineation and planting of proposed mitigation areas as identified in the MHMP, and the stabilization of disturbed soils upon completion of construction. Wastewater will be handled onsite through the use of a new septic system designed and installed by others. M.ZEA ' F WAsio4,CoQi Z n I Ss 01C) 31I1` • • ,oON `OGS DEPARTMENT OF COMMUNITY DEVELOPMENT 621 Sheridan Street,Port Townsend,WA 98368 Tel:360.3794450 I Fax:360.379.4451 Web:www.co.iefferson.wa.us/communitydevelopment F.-mail:dcd@co,iefferson.wa.us � SW/NG��� STORMWATER CALCULATION WORKSHEET MIA# PROJECT/APPLICANT NAME: qiyk 414%t ✓FZ 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., SITE) Size of parcel 0.274 acres An acre contains 43,560 square feet. Multiply the acreage by this figure. Size of parcel in square feet 11,935 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. LAND DISTURBING ACTIVITY,CONVERSION OF NATIVE VEGETATION,AND VOLUME OF CUT/FILL 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 3/a acres or more of Construction site for structures 510 sq/ft native vegetation to lawn or landscaped areas? Drainfield,septic tank, etc. 1,430 sq/ft Circle: Yes No Well, utilities,etc. 0 sq/ft Does the project convert 2'A acres or more of native vegetation to pasture? Driveway, parking, roads,etc. 0 sq/ft Circle: Yes ( No—) Lawn, landscaping, etc. 0 sq/ft Other compacted surface, etc. ° sq/ft Indicate Total Volumes of Proposed: Total Land Disturbance 1,940 sq/ft Cut 0 Fill 0 (cu/yd) 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.10/20/2014 1 • • FIGURE 1 : NEW DEVELOPMENT Start Here Does the site have Yes See Redevelopment 35%or more of Minimum existing impervious Requirements and coverage? Flow Chart (Figure 2) No Does the project convert% acres or more of native vegetation to lawn or Does the project add No landscaped areas,or 5,000 square feet or , convert 2.5 acres or more more of new of native vegetation to impervious surfaces? pasture? Yes Yes No Does the project have 2,000 square feet or "LARGE" PROJECT more of new, replaced, All Minimum Requirements or new plus replaced apply to the new impervious impervious surfaces? surfaces and converted pervious surfaces. Yes No "MEDIUM" PROJECT Does the project have Minimum Requirements#1 land-disturbing through#5 apply to the new activities of 7,000 Yes square feet or more? and replaced impervious s q surfaces and the land disturbed. No • "SMALL" PROJECT See Minimum Requirement#2, Construction Stormwater Pollution Prevention Based on Fig.2.2 from 2001 Ecology Stormwater Management Manna!for Western Washington • . FIGURE 2: REDEVELOPMENT Do the new, replaced, or new plus replaced impervious surfaces total 2,000 square feet or more? OR Does the land disturbing activity total 7,000 square feet or more? Yes No "MEDIUM" PROJECT "SMALL" PROJECT Minimum Requirements#1 through#5 Apply Minimum Requirement#2, apply to the new and replaced impervious Construction Stormwater Pollution surfaces and the land disturbed. Prevention Next Question • Does the project add 5,000 square feet or more of new impervious surfaces? OR Convert 3/4 acres or more of native vegetation to lawn or landscaped areas? OR Convert 2.5 acres or more of native vegetation to pasture? Yes No Next • "LARGE" PROJECT Question • Is this a road- Minimum Requirements#1 through #10 related project? apply to the new impervious surfaces Yes and the converted pervious surfaces. No Does the project add 5,000 square feet or more of new impervious surfaces? Yes No Do new impervious surfaces add 50% or Is the total of the new plus replaced more to the existing impervious surfaces impervious surfaces 5,000 square feet or within the project limits? more, AND does the value of the proposed improvements —including No Yes interior improvements—exceed 50%of the dvalue (or replacement value) No additional of theassesseexisting valsite improvements? requirements Yes No No additional Minimum Requirements#1 through #10 requirements apply to the new and replaced impervious surfaces. Based on Fig.2.3 from 2001 Ecology Stormwater Management,Llomma!for Western Washington • • 4Cii‘k, dJEFFERSON COUNTY 04 DEPARTMENT OF COMMUNITY DEVELOPMENT ____7 621 Sheridan Street • Port Townsend •Washington 98368 � O$ 360/379-4450 • 360/379-4451 Fax 8IN0 http://www.co.jefferson.wa.us/commdevelopment/ Construction Stormwater Pollution Prevention Best Management Practices (BMPs) Packet For"small" projects(as determined through the Stormwater Calculation Worksheet),the applicant shall consider the twelve Construction Stormwater Pollution Prevention elements and implement applicable BMPs. A set of useful BMPs for typical rural residential construction is attached. There is no additional submittal required as part of the permit application. For"medium"and"large"projects, the Construction Stormwater Pollution Prevention Plan (SWPPP)is part of the overall Stormwater Site Plan required as part of the permit application. Refer to the Stormwater Management Information Sheet for guidance. The following twelve elements must be considered for Construction Stormwater Pollution Prevention before and during the construction phase of the project: 1. Mark Clearing Limits 7. Protect Drain Inlets 2. Establish Construction Access 8. Stabilize Channels and Outlets 3. Control Flow Rates 9. Control Pollutants 4. Install Sediment Controls 10. Control De-Watering 5. Stabilize Soils 11. Maintain Best Management Practices 6. Protect Slopes 12. Manage The Project Each of the twelve elements is described in more detail below: 1. Mark Clearing Limits By minimizing the limits of clearing on the site, a builder can minimize stormwater runoff and provide effective control of pollution. 2. Establish Construction Access Much of the sediment that leaves a construction site does so on the wheels of delivery and construction vehicles that drive off a project site. Construction access must be limited to a single location and a properly constructed Stabilized Construction Entrance(BMP C105) should be included on the site. 3. Control Flow Rates Stormwater that leaves a project site unimpeded may exceed the capacity of the existing stormwater control facilities downstream and may contain sediment that may be deposited as the velocity of the runoff decreases. Stormwater protection on a construction site should include measures to control the flow rate of runoff from the site. This can be done by installing a Sediment Trap(BMP C240)or other measure that will impede the flow of water off a construction site. 4. Install Sediment Controls In addition to limiting the rate of stormwater flow off a construction site, measures should be put in place to treat the runoff and remove sediment. Limiting of the cleared area (Element 1)will assist in this effort, but there will be exposed soils that may move with the runoff. Suggested BMPs for controlling sediment include Straw Bale Barriers(BMPC230), Brush Barrier(BMP C231), Gravel Filter Berm (BMP C232), and Silt Fence(BMP C233). Installation of a Sediment Trap (Element 3)is an additional sediment control feature. construction SWPP.doc Page 1 10/12/2003 s 5. Stabilize Soils An additional measure that can minimize sediment transport in runoff is to stabilize soils on the site with mulch or some other covering. This will limit the amount of soil that is exposed to rainfall, thus limiting the sediment that could potentially leave the site. BMPs that could be used for this include Mulching (BMP C121), Nets and Blankets(BMP C122), and Plastic Covering(BMP C123). During periods of dry weather dust can become a problem and sediment could be transported from the site in high winds. BMP C140 Dust Control should be followed to limit loss of soils in windy conditions. 6. Protect Slopes If the cleared area includes slopes of 3:1 (Horizontal: Vertical)or steeper,the slopes should be protected to limit runoff. If the slopes are not protected, rills and gullies may form,transporting sediment to the lower elevations and potentially off the construction site. The slopes should be graded to minimize erosion and runoff at the downstream end of the slopes, and runoff should be collected and treated. The following BMPs could be used Surface Roughening (BMP C130), Interceptor Dike and Swale(BMP C200), and Pipe Slope Drains(BMP C204). 7. Protect Drain Inlets Runoff from urban construction sites often discharges into existing stormwater collection systems. Water enters the collection system through drain inlets. If there are drain inlets downstream of a construction site,they should be protected using BMP C220 Storm Drain Inlet Protection. 8. Stabilize Channels and Outlets Any temporary on-site channels or ditches that are used to control runoff should be stabilized to prevent erosion in the channel. BMP C202 Channel Lining and BMP C209 Outlet Protection should be used. 9. Control Pollutants The best way to control pollution is to limit the source of pollution. Construction debris should be maintained in a safe location. Vehicle maintenance on the construction site should be minimized and any spill should be promptly cleaned up. Concrete spillage should be kept to a minimum and cleaning of the concrete trucks after they have unloaded should be done in an area that will not drain off site(see BMP C151 Concrete Handling). 10. Control Dewatering In some cases, excavation for the foundation or below ground structures will encounter ground water. This water must be removed(dewatered)from the excavation. Discharge of this ground water must be treated in a manner that will not cause damage downstream due to flow rates or added pollution. There are no specific BMP identified for this activity, but the water should be handled with care to assure that soils or other pollutants are not added to this flow. 11. Maintain BMPs Installation of the appropriate BMPs is not adequate to completely control stormwater runoff. The BMPs that have been installed on the project must be inspected and maintained during the duration of the construction project. In addition,the temporary controls that were installed for construction should be removed within 30 days of completion of the work. Typically, once construction has been completed,the temporary facilities are not maintained, and by removing the facilities, it will ensure that these won't fail and discharge water or sediment that had been previously trapped or contained. 12. Manage the Project Management of a project has four aspects: 1. Phasing construction to prevent transportation of runoff and sediment, 2. Limiting the work during seasons where large amounts of rainfall could be anticipated, 3. Coordination with Utilities and other Contractors, and 4. Inspection and Monitoring. All of these for aspects are important and must be followed to ensure a project that will have minimal impact on the environment. Volume II of the Manual contains additional BMPs that could be used on-site. The applicant is encouraged to review the Manual to see if other BMPs may be applicable to, or more useful on, a particular site. construction SWPP.doc Page 2 10/12/2003 DRAINAGE & EROSION CONTROL PLAN FOR MATSUNAMI SINGLE FAMILY RESIDENCE ANN MATSUNAMI 1650 LILIHA ST. HONOLULU,HAWAII 96817 — D TIi MAR 3 1 2015 PROJECT LOCATION: j [j 190 BEE MILL RD BRINNON'WA JEFFERSON COUNTY CkPT.OF COMMUNITY DEVELOPMENT PARCEL No: 963-900-023 Prepared for: APPROVED JEFFERSON COUNTY BT RMWATER PLAN 1820 JEFFERSON ST PORT TOWNSEND,WASHINGTON 98368 APR - 5 2011 . •, 4 I is Prepared by: � - ZENOVIC&ASSOCIATES,INCORPORATED / er 301 EAST 611I STREET,SUITE#1 PORT ANGELES,WASHINGTON 98362 Project No. 14288 March 17,2015 • • DRAINAGE&EROSION CONTROL PLAN& PROJECT OVERVIEW A single family residence (approx. 1,110 sq. ft. footprint) will be constructed in lot 17 of Jackson Cove Park, address 190 Bee Mill Road, Jefferson County parcel number 963- 900-023; the lot is 0.274 acres in size. There is an existing home, garage, asphalt driveway, and septic system on site. Total impervious area on the site is approximately 4,408 sq. ft. with approximately 575 sq. ft. of decking surrounding the residence. Existing impervious surfaces cover approximately 36.9% of the parcel. The existing home will be demolished and removed, along with a portion of the existing asphalt driveway/parking to construct and install a new septic system. An existing green house and covered platform have been removed. Upon completion of the proposed development there will be a total of 3,902 sq. ft. of impervious surfacing (asphalt, garage roof,proposed roof) and 250 sq. ft. of exposed decking. An anticipated 144 sq. ft. of concrete will be poured surrounding a hot tub. The construction would result in the removal of approximately 506 sq. ft. of impervious surfacing. The resulting percent impervious area would be reduced to 32.7%. Based on the Stormwater Calculation Worksheet(see attached) for Jefferson County, the project is classified as a"small"project/redevelopment. With this classification only Minimum Requirement#2 is applicable, which entails considering the twelve (12) Construction Stormwater Pollution Prevention(SWPP) Best Management Practices during construction. The information packet is attached. Detailed erosion and sediment control practices,procedures, and timing are outlined in the WESTECH COMPANY Mitigation and Habitat Management Plan (MHMP), location of BMP's can be found on the provided site plan. Downspout splash blocks (minimum 3) should be constructed to promote dispersion and infiltration of roof runoff. Based on the findings in the MHMP the soils in the proposed construction area vary from Grove very gravelly sand(GrC) and Olete-Hoodsport Complex (OpD). The first 20-30 inches of both soils are well draining, utilizing splash blocks will allow for onsite retention/infiltration and help reduce erosion and rifling to the east. Construction activity will include the demolition and removal of existing asphalt and home, excavation and grading for the proposed S.F.R., construction and installation of the proposed septic system (designed by others), excavation and installation of new utilities, construction of the proposed home, construction and installation of stormwater structures(splash blocks), Construction of stairs/pathway to the tidal flats, delineation and planting of proposed mitigation areas as identified in the MHMP, and the stabilization of disturbed soils upon completion of construction. Wastewater will be handled onsite through the use of a new septic system designed and installed by others. M.2.&,. �S' pF WAsy�� O � oG '% c 5 o SSIONAL?r_ 3011` • ¢SON DEPARTMENT OF COMMUNITY DEVELOPMENT a621 Sheridan Street,Port Townsend,W.1 98368 r Tel:360379.4450 j fax:360.379.4451 Web:www.co.iefferson.wa.us/communitydevelopment E-mail:dcd@co.iefferson.wa.us `5. N G SO STORMWATER CALCULATION WORKSHEET MLA# PROJECT/APPLICANT NAME: ilkidik 41AS. S rIr_ 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., SITE) Size of parcel 0.274 acres An acre contains 43,560 square feet. Multiply the acreage by this figure. Size of parcel in square feet 11,935 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. LAND DISTURBING ACTIVITY,CONVERSION OF NATIVE VEGETATION,AND VOLUME OF CUT/FILL 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 a/4 acres or more of Construction site for structures 510 sq/ft native vegetation to lawn or landscaped areas? Drainfield,septic tank, etc. 1,430 sq/ft Circle: Yes No Well, utilities, etc. 0 sq/ft Does the project convert 2'A acres or more of native vegetation to pasture? Driveway, parking, roads,etc. 0 sq/ft Circle: Yes �No� Lawn, landscaping,etc. 0 sq/ft Other compacted surface, etc. 0 sq/ft Indicate Total Volumes of Proposed: Total Land Disturbance 1,940 sq/ftCut 0 Fill 0 (cu/yd) 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. stormwaler calc worksheet-REV.10/20/2014 1 • • • FIGURE 1 : NEW DEVELOPMENT Start Here Does the site have Yes See Redevelopment 35%or more of Minimum existing impervious Requirements and coverage? Flow Chart (Figure 2) No Does the project convert 1/4 acres or more of native vegetation to lawn or Does the project add No landscaped areas, or 5,000 square feet or convert 2.5 acres or more more of new of native vegetation to impervious surfaces? pasture? Yes Yes NNo Does the project have 2,000 square feet or "LARGE" PROJECT more of new, replaced, All Minimum Requirements or new plus replaced apply to the new impervious impervious surfaces? surfaces and converted pervious surfaces. Yes No "MEDIUM" PROJECT Does the project have Minimum Requirements #1 land-disturbing • through#5 apply to the new activities of 7,000 and replaced impervious Yes square feet or more? surfaces and the land disturbed. No "SMALL" PROJECT See Minimum Requirement#2, Construction Stormwater Pollution Prevention Based on Fig.2.2 from 2001 Ecology Starmwater Management Manual for Western Washington • • FIGURE 2: REDEVELOPMENT Do the new, replaced, or new plus replaced impervious surfaces total 2,000 square feet or more? OR Does the land disturbing activity total 7,000 square feet or more? Yes No V "MEDIUM" PROJECT "SMALL" PROJECT Minimum Requirements#1 through #5 Apply Minimum Requirement#2, apply to the new and replaced impervious Construction Stormwater Pollution surfaces and the land disturbed. Prevention Next Question Does the project add 5,000 square feet or more of new impervious surfaces? OR Convert%acres or more of native vegetation to lawn or landscaped areas? OR Convert 2.5 acres or more of native vegetation to pasture? Yes No Next "LARGE" PROJECT QuestionN. Is this a road Minimum Requirements#1 through #10 related project? apply to the new impervious surfaces Yes and the converted pervious surfaces. No Does the project add 5,000 square feet or more of new impervious surfaces? Yes No Do new impervious surfaces add 50%or Is the total of the new plus replaced more to the existing impervious surfaces impervious surfaces 5,000 square feet or within the project limits? more, AND does the value of the proposed improvements— including No Yes interior improvements—exceed 50%of y the assessed value (or replacement value) No additional of the existing site improvements? requirements Yes No No additional Minimum Requirements#1 through #10 requirements apply to the new and replaced impervious surfaces. Based on Fig.2.3 from 2001 Ecology Stormwater Management Manual for Western Washington • • ,4,5Ox cb �4 .4. JEFFERSON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT Sheridan Street • Port Townsend • Washington 98368 \\\\\\\ Q 360/379-4450 • 360/379-4451 Fax �`�`F37NG� http:llwww.co.jefferson.wa.us/commdevelopment/ Construction Stormwater Pollution Prevention Best Management Practices (BMPs) Packet For"small" projects(as determined through the Stormwater Calculation Worksheet), the applicant shall consider the twelve Construction Stormwater Pollution Prevention elements and implement applicable BMPs. A set of useful BMPs for typical rural residential construction is attached. There is no additional submittal required as part of the permit application. For"medium" and "large" projects, the Construction Stormwater Pollution Prevention Plan (SWPPP) is part of the overall Stormwater Site Plan required as part of the permit application. Refer to the Stormwater Management Information Sheet for guidance. The following twelve elements must be considered for Construction Stormwater Pollution Prevention before and during the construction phase of the project: 1. Mark Clearing Limits 7. Protect Drain Inlets 2. Establish Construction Access 8. Stabilize Channels and Outlets 3. Control Flow Rates 9. Control Pollutants 4. Install Sediment Controls 10. Control De-Watering 5. Stabilize Soils 11. Maintain Best Management Practices 6. Protect Slopes 12. Manage The Project Each of the twelve elements is described in more detail below: 1. Mark Clearing Limits By minimizing the limits of clearing on the site, a builder can minimize stormwater runoff and provide effective control of pollution. 2. Establish Construction Access Much of the sediment that leaves a construction site does so on the wheels of delivery and construction vehicles that drive off a project site. Construction access must be limited to a single location and a properly constructed Stabilized Construction Entrance (BMP C105) should be included on the site. 3. Control Flow Rates Stormwater that leaves a project site unimpeded may exceed the capacity of the existing stormwater control facilities downstream and may contain sediment that may be deposited as the velocity of the runoff decreases. Stormwater protection on a construction site should include measures to control the flow rate of runoff from the site. This can be done by installing a Sediment Trap (BMP C240)or other measure that will impede the flow of water off a construction site. 4. Install Sediment Controls In addition to limiting the rate of stormwater flow off a construction site, measures should be put in place to treat the runoff and remove sediment. Limiting of the cleared area (Element 1)will assist in this effort, but there will be exposed soils that may move with the runoff. Suggested BMPs for controlling sediment include Straw Bale Barriers (BMPC230), Brush Barrier(BMP C231), Gravel Filter Berm (BMP C232), and Silt Fence (BMP C233). Installation of a Sediment Trap (Element 3) is an additional sediment control feature. construction SWPP.doc Page 1 10/12/2003 • S 5. Stabilize Soils An additional measure that can minimize sediment transport in runoff is to stabilize soils on the site with mulch or some other covering. This will limit the amount of soil that is exposed to rainfall, thus limiting the sediment that could potentially leave the site. BMPs that could be used for this include Mulching (BMP C121), Nets and Blankets(BMP C122), and Plastic Covering (BMP C123). During periods of dry weather dust can become a problem and sediment could be transported from the site in high winds. BMP C140 Dust Control should be followed to limit loss of soils in windy conditions. 6. Protect Slopes If the cleared area includes slopes of 3:1 (Horizontal: Vertical) or steeper, the slopes should be protected to limit runoff. If the slopes are not protected, rills and gullies may form, transporting sediment to the lower elevations and potentially off the construction site. The slopes should be graded to minimize erosion and runoff at the downstream end of the slopes, and runoff should be collected and treated. The following BMPs could be used Surface Roughening (BMP C130), Interceptor Dike and Swale (BMP C200), and Pipe Slope Drains(BMP C204). 7. Protect Drain Inlets Runoff from urban construction sites often discharges into existing stormwater collection systems. Water enters the collection system through drain inlets. If there are drain inlets downstream of a construction site, they should be protected using BMP C220 Storm Drain Inlet Protection. 8. Stabilize Channels and Outlets Any temporary on-site channels or ditches that are used to control runoff should be stabilized to prevent erosion in the channel. BMP C202 Channel Lining and BMP C209 Outlet Protection should be used. 9. Control Pollutants The best way to control pollution is to limit the source of pollution. Construction debris should be maintained in a safe location. Vehicle maintenance on the construction site should be minimized and any spill should be promptly cleaned up. Concrete spillage should be kept to a minimum and cleaning of the concrete trucks after they have unloaded should be done in an area that will not drain off site (see BMP C151 Concrete Handling). 10. Control Dewatering In some cases, excavation for the foundation or below ground structures will encounter ground water. This water must be removed (dewatered)from the excavation. Discharge of this ground water must be treated in a manner that will not cause damage downstream due to flow rates or added pollution. There are no specific BMP identified for this activity, but the water should be handled with care to assure that soils or other pollutants are not added to this flow. 11. Maintain BMPs Installation of the appropriate BMPs is not adequate to completely control stormwater runoff. The BMPs that have been installed on the project must be inspected and maintained during the duration of the construction project. In addition, the temporary controls that were installed for construction should be removed within 30 days of completion of the work. Typically, once construction has been completed, the temporary facilities are not maintained, and by removing the facilities, it will ensure that these won't fail and discharge water or sediment that had been previously trapped or contained. 12. Manage the Project Management of a project has four aspects: 1. Phasing construction to prevent transportation of runoff and sediment, 2. Limiting the work during seasons where large amounts of rainfall could be anticipated, 3. Coordination with Utilities and other Contractors, and 4. Inspection and Monitoring. All of these for aspects are important and must be followed to ensure a project that will have minimal impact on the environment. Volume II of the Manual contains additional BMPs that could be used on-site. The applicant is encouraged to review the Manual to see if other BMPs may be applicable to, or more useful on, a particular site. construction SWPP.doc Page 2 10112/2003 • • DRAINAGE & EROSION CONTROL PLAN FOR MATSUNAMI SINGLE FAMILY RESIDENCE ANN MATSUNAMI 1650 LILIIIA ST. HONOLULU,HAWAII 96817 \D) E0E0Vail PROJECT LOCATION: �,I MAR 3 1 2015 190 BEE MILL RD � i� BRINNON,WA JEFFERSON COUNTY PARCEL No:963-900-023 I _DEPT OF COMMUNITY DEVELOPMENT Prepared for: JEFFERSON COUNTY 1820 JEFFERSON ST PORT TOWNSEND,WASHINGTON 98368 Prepared by: ZENOVIC&ASSOCIATES,INCORPORATED 301 EAST 6T11 STREET,SUITE#1 PORT ANGELES,WASHINGTON 98362 Project No. 14288 March 17,2015 • • DRAINAGE&EROSION CONTROL PLAN&PROJECT OVERVIEW A single family residence (approx. 1,110 sq. ft. footprint) will be constructed in lot 17 of Jackson Cove Park, address 190 Bee Mill Road,Jefferson County parcel number 963- 900-023; the lot is 0.274 acres in size. There is an existing home, garage, asphalt driveway, and septic system on site. Total impervious area on the site is approximately 4,408 sq. ft. with approximately 575 sq. ft. of decking surrounding the residence. Existing impervious surfaces cover approximately 36.9% of the parcel. The existing home will be demolished and removed, along with a portion of the existing asphalt driveway/parking to construct and install a new septic system. An existing green house and covered platform have been removed. Upon completion of the proposed development there will be a total of 3,902 sq. ft. of impervious surfacing (asphalt, garage roof, proposed roof) and 250 sq. ft. of exposed decking. An anticipated 144 sq. ft. of concrete will be poured surrounding a hot tub. The construction would result in the removal of approximately 506 sq. ft. of impervious surfacing. The resulting percent impervious area would be reduced to 32.7%. Based on the Stormwater Calculation Worksheet(see attached) for Jefferson County, the project is classified as a"small"project/redevelopment. With this classification only Minimum Requirement#2 is applicable, which entails considering the twelve (12) Construction Stormwater Pollution Prevention (SWPP) Best Management Practices during construction. The information packet is attached. Detailed erosion and sediment control practices,procedures, and timing are outlined in the WESTECH COMPANY Mitigation and Habitat Management Plan (MHMP), location of BMP's can be found on the provided site plan. Downspout splash blocks (minimum 3) should be constructed to promote dispersion and infiltration of roof runoff. Based on the findings in the MHMP the soils in the proposed construction area vary from Grove very gravelly sand (GrC) and Olete-Hoodsport Complex (OpD). The first 20-30 inches of both soils are well draining, utilizing splash blocks will allow for onsite retention/infiltration and help reduce erosion and rilling to the east. Construction activity will include the demolition and removal of existing asphalt and home, excavation and grading for the proposed S.F.R., construction and installation of the proposed septic system (designed by others), excavation and installation of new utilities, construction of the proposed home, construction and installation of stormwater structures (splash blocks), Construction of stairs/pathway to the tidal flats, delineation and planting of proposed mitigation areas as identified in the MHMP, and the stabilization of disturbed soils upon completion of construction. Wastewater will be handled onsite through the use of a new septic system designed and installed by others. 4M.ppA cn x,11► 4fsr9� SsloNAl .. • • DEPARTMENT OF COMMUNITY DEVELOPMENT 621 Sheridan Street,Port Townsend,W. 98368 Tek 360.379.4450 I 1"ax:360.379.4451 Web:www.co.icffcrson.wa.us/eommunitydevelopmcn( t?-mail:dcd c@co_ieffco.on.wa.us �QSIJNGt�� STORMWATER CALCULATION WORKSHEET M LA it PROJECT/APPLICANT NAME: 1140-$4.01A.‘Ntii DV„ DETERMINING STORM WATER 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.,SITE) Size of parcel 0.274 acres An acre contains 43,560 square feet. Multiply the acreage by this figure. Size of parcel in square feet 1 1'935 _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. LAND DISTURBING ACTIVITY,CONVERSION OF NATIVE VEGETATION, AND VOLUME OF CUT/FILL 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 510 sq/ft native vegetation to lawn or landscaped areas? Drainfield,septic tank,etc. 1,430 sq/ft Circle: Yes LNo� Well, utilities,etc. 0 sq/ft Does the project convert 2%acres or more of native vegetation to pasture? Driveway, parking, roads,etc. 0 sq/ft Circle: Yes (NoJ Lawn, landscaping, etc. 0 sq/ft Other compacted surface,etc. 0 sq/ft Indicate Total Volumes of Proposed: Total Land Disturbance 1,940 sq/ft Cut 0 Fill 0 (cu/yd) 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.10/202014 1 • • STORMWATER CALULATIONS-IMPERVIOUS SURFACE NEW EXISTING Structures(all roof area) +250 sq/ft Structures(all roof area) 2,485 sq/ft Sidewalks 0 sq/ft Sidewalks 0 sq/ft Patios sq/ft Patios 0 sq/ft Solid Decks +144 sq/ft Solid Decks 0 sq/ft (without infiltration below) (without infiltration below) Driveway, parking, roads, etc -900 sq/ft Driveway,parking, roads, etc 1,923 sq/ft Other NONE sq/ft Other NONE sq/ft Total New -506 sq/ft Total Existing 4,40$ sq/ft TOTAL NEW+ TOTAL EXISTING* 3,902 sq/ft *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 Divide the total existing impervious surface above by the size of the parcel and convert to a percentage: 36.9 a/o Does the site have 35% or more of existing impervious surface? Circle: Yes [ No El 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#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 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. 3/341/ (LAN R OR AUTHORIZED REPRESENTATIVE SIGNATURE) (DATE) FOR OFFICE USE ONLY SMALL MEDIUM LARGE REDEVELOPMENT Stormwater Site Plan: Yes No Stormwater talc worksheet—REV.10/20/2014 • • STORMWATER CALULATIONS-IMPERVIOUS SURFACE NEW EXISTING Structures(all roof area) +250 sq/ft Structures(all roof area) 2,485 sq/ft Sidewalks 0 sq/ft Sidewalks 0 sq/ft Patios 0 sq/ft Patios 0 sq/ft Solid Decks +144 sq/ft Solid Decks 0 sq/ft (without infiltration below) (without infiltration below) Driveway, parking, roads, etc -900 sq/ft Driveway,parking, roads,etc 1,923 sq/ft Other NONE sq/ft Other NONE sq/ft Total New -506 sq/ft Total Existing 4,408 sq/ft TOTAL NEW+ TOTAL EXISTING` 3,902 sq/ft "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 Divide the total existing impervious surface above by the size of the parcel and convert to a percentage: 36.9 Does the site have 35%or more of existing impervious ervious surface? Circle: Yes 7 No 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#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 Instructions and Submittal Template or prepare a Stormwater Site Plan using the step-by-step guidance in the Storm water Management Manual. APPLICANT SIGNATURE By signing the Storm water 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. /., 3131//( (LAN.,fig R OR AUTHORIZED REPRESENTATIVE SIGNATURE) (:4,E) kit OFFICE USE ONLY SMALL MEDIUM LARGE REDEVELOPMENT Starmwater Site Plan: Yes No storrrrwater Calc worksheet—REV.1020/2014 . • • • FIGURE 1 : NEW DEVELOPMENT Start Here Does the site have Yes See Redevelopment 35%or more of Minimum existing impervious Requirements and coverage? Flow Chart (Figure 2) No Does the project convert 3/4 acres or more of native • vegetation to lawn or Does the project add No landscaped areas, or 5,000 square feet or convert 2.5 acres or more more of new of native vegetation to impervious surfaces? pasture? Yes Yes No Does the project have • 2,000 square feet or "LARGE" PROJECT more of new, replaced, All Minimum Requirements or new plus replaced apply to the new impervious impervious surfaces? surfaces and converted pervious surfaces. Y� No "MEDIUM" PROJECT Does the project have Minimum Requirements#1 land-disturbing through#5 apply to the new Yes activities of 7,000 and replaced impervious square feet or more? surfaces and the land disturbed. No • "SMALL" PROJECT See Minimum Requirement#2, Construction Stormwater Pollution Prevention Based on Fig.2.2 from 2001 Ecology Stormwater Management Manual for Western Washington • 410 FIGURE 2: REDEVELOPMENT Do the new, replaced, or new plus replaced impervious surfaces total 2,000 square feet or more? OR Does the land disturbing activity total 7,000 square feet or more? Yes No S f "MEDIUM"PROJECT "SMALL" PROJECT Minimum Requirements#1 through#5 Apply Minimum Requirement#2, apply to the new and replaced impervious Construction Stormwater Pollution surfaces and the land disturbed. Prevention Next Question • Does the project add 5,000 square feet or more of new impervious surfaces? OR Convert 3/4 acres or more of native vegetation to lawn or landscaped areas? OR Convert 2.5 acres or more of native vegetation to pasture? Yes No Next • "LARGE" PROJECT Question Is this a road- Minimum Requirements#1 through #10 related project? apply to the new impervious surfaces Yes and the converted pervious surfaces. No Does the project add 5,000 square feet or more of new impervious surfaces? Yes No ♦ • Do new impervious surfaces add 50%or Is the total of the new plus replaced more to the existing impervious surfaces impervious surfaces 5,000 square feet or within the project limits? more, AND does the value of the proposed improvements— including No Yes interior improvements—exceed 50% of Yes the assessed value(or replacement value) No additional of the existing site improvements? requirements No No additional Minimum Requirements#1 through #10 requirements apply to the new and replaced impervious surfaces. Based on Fig.2.3 from 2001 Ecology Stormwater Management Manua!for Western Washington • i ��`�'4sON c°�� JEFFERSON COUNTY a •4 DEPARTMENT OF COMMUNITY DEVELOPMENT 621 Sheridan Street • Port Townsend • Washington 98368 Sys A.0 360/379-4450 . 360/379-4451 Fax FANG http://www.co.jefferson.wa.us/commdevelopment/ Construction Stormwater Pollution Prevention Best Management Practices (BMPs) Packet For"small"projects(as determined through the Stormwater Calculation Worksheet), the applicant shall consider the twelve Construction Stormwater Pollution Prevention elements and implement applicable BMPs. A set of useful BMPs for typical rural residential construction is attached. There is no additional submittal required as part of the permit application. For"medium" and "large' projects, the Construction Stormwater Pollution Prevention Plan (SWPPP) is part of the overall Stormwater Site Plan required as part of the permit application. Refer to the Stormwater Management Information Sheet for guidance. The following twelve elements must be considered for Construction Stormwater Pollution Prevention before and during the construction phase of the project: 1. Mark Clearing Limits 7. Protect Drain Inlets 2. Establish Construction Access 8. Stabilize Channels and Outlets 3. Control Flow Rates 9. Control Pollutants 4. Install Sediment Controls 10. Control De-Watering 5. Stabilize Soils 11. Maintain Best Management Practices 6. Protect Slopes 12. Manage The Project Each of the twelve elements is described in more detail below: 1. Mark Clearing Limits By minimizing the limits of clearing on the site, a builder can minimize stormwater runoff and provide effective control of pollution. 2. Establish Construction Access Much of the sediment that leaves a construction site does so on the wheels of delivery and construction vehicles that drive off a project site. Construction access must be limited to a single location and a properly constructed Stabilized Construction Entrance (BMP C105) should be included on the site. 3. Control Flow Rates Stormwater that leaves a project site unimpeded may exceed the capacity of the existing stormwater control facilities downstream and may contain sediment that may be deposited as the velocity of the runoff decreases. Stormwater protection on a construction site should include measures to control the flow rate of runoff from the site. This can be done by installing a Sediment Trap (BMP C240)or other measure that will impede the flow of water off a construction site. 4. Install Sediment Controls In addition to limiting the rate of stormwater flow off a construction site, measures should be put in place to treat the runoff and remove sediment. Limiting of the cleared area (Element 1)will assist in this effort, but there will be exposed soils that may move with the runoff. Suggested BMPs for controlling sediment include Straw Bale Barriers(BMPC230), Brush Barrier(BMP C231), Gravel Filter Berm (BMP C232), and Silt Fence (BMP C233). Installation of a Sediment Trap (Element 3) is an additional sediment control feature. construction SWPP.doc Page 1 10/12/2003 5. Stabilize Soils An additional measure that can minimize sediment transport in runoff is to stabilize soils on the site with mulch or some other covering. This will limit the amount of soil that is exposed to rainfall, thus limiting the sediment that could potentially leave the site. BMPs that could be used for this include Mulching (BMP C121), Nets and Blankets(BMP C122), and Plastic Covering (BMP C123). During periods of dry weather dust can become a problem and sediment could be transported from the site in high winds. BMP C140 Dust Control should be followed to limit loss of soils in windy conditions. 6. Protect Slopes If the cleared area includes slopes of 3:1 (Horizontal: Vertical) or steeper, the slopes should be protected to limit runoff. If the slopes are not protected, rills and gullies may form, transporting sediment to the lower elevations and potentially off the construction site. The slopes should be graded to minimize erosion and runoff at the downstream end of the slopes, and runoff should be collected and treated. The following BMPs could be used Surface Roughening (BMP C130), Interceptor Dike and Swale (BMP C200), and Pipe Slope Drains (BMP C204). 7. Protect Drain Inlets Runoff from urban construction sites often discharges into existing stormwater collection systems. Water enters the collection system through drain inlets. If there are drain inlets downstream of a construction site, they should be protected using BMP C220 Storm Drain Inlet Protection. 8. Stabilize Channels and Outlets Any temporary on-site channels or ditches that are used to control runoff should be stabilized to prevent erosion in the channel. BMP C202 Channel Lining and BMP C209 Outlet Protection should be used. 9. Control Pollutants The best way to control pollution is to limit the source of pollution. Construction debris should be maintained in a safe location. Vehicle maintenance on the construction site should be minimized and any spill should be promptly cleaned up. Concrete spillage should be kept to a minimum and cleaning of the concrete trucks after they have unloaded should be done in an area that will not drain off site(see BMP C151 Concrete Handling). 10. Control Dewatering In some cases, excavation for the foundation or below ground structures will encounter ground water. This water must be removed (dewatered)from the excavation. Discharge of this ground water must be treated in a manner that will not cause damage downstream due to flow rates or added pollution. There are no specific BMP identified for this activity, but the water should be handled with care to assure that soils or other pollutants are not added to this flow. 11. Maintain BMPs Installation of the appropriate BMPs is not adequate to completely control stormwater runoff. The BMPs that have been installed on the project must be inspected and maintained during the duration of the construction project. In addition, the temporary controls that were installed for construction should be removed within 30 days of completion of the work. Typically, once construction has been completed,the temporary facilities are not maintained, and by removing the facilities, it will ensure that these won't fail and discharge water or sediment that had been previously trapped or contained. 12. Manage the Project Management of a project has four aspects: 1. Phasing construction to prevent transportation of runoff and sediment, 2. Limiting the work during seasons where large amounts of rainfall could be anticipated, 3. Coordination with Utilities and other Contractors, and 4. Inspection and Monitoring. All of these for aspects are important and must be followed to ensure a project that will have minimal impact on the environment. Volume II of the Manual contains additional BMPs that could be used on-site. The applicant is encouraged to review the Manual to see if other BMPs may be applicable to, or more useful on, a particular site. construction SWPP.doc Page 2 10112/2003