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Home My WebLink AboutLog122 ... . .. Discovery Bay Golf Course - Grading Permit Stormwater Memo for Road Grading Page 6 of 6 Totals 4.55 2.29 199.10 Minimum Requirement #8: Wetlands Protection. This requirement only applies to stormwater being discharged directly into a wetland, either directly or indirectly. Currently there is a Class A wetland onsite. Stormwater from the proposed roadways will have to sheet flow over native vegetation and golf course landscaping before entering wetland, similar to existing conditions. Since the stormwater will be infiltrated at the roadway with any excess runoff discharged as sheetflow through a gravel bed, stormwater flows will not change significantly from existing conditions. Minimum Requirement #9: Watershed Planning. This minimum requirement is not applicable, as there are no known specific basin or watershed concerns. The LID design standards that will be used for the roadways will limit the impact of stormwater flows, both in quantity and quality. Minimum Requirement #10: Operation and Maintenance. The project stormwater facilities requiring special maintenance are the porous pavement areas. SpeCific operation and maintenance guidelines for porous pavement are in Attachment #3 of this memorandum. lRECEI'TED ;;.. ..~:_:' (": k ~ 11;.; lJ " ~ ,,"'..... JEffERSON COUNTY OeD ..l~.'..~...._._..w>. IJ . Discovery Bay Golf Course - Grading Permit Stormwater Memo for Road Grading Page 5 of 6 Table 2. Summary of Culvert 100 Year, 24 hour Storm Event Flow Rates Culvert ID Drainage Area 100 Year Flowrate Forested Pasture (acres) (cfs) (cfs) 1 10.263 0.81 0.69 2 3.267 0.26 0.22 3 18.819 1.49 1.27 4 3.509 0.28 0.24 5 10.126 0.80 0.68 6 33.235 2.63 2.24 Note the proposed culverts are 24" in diameter, which are capable of handling up to 10 cfs flows with 2 feet of headwater. The culverts will be able to safely pass the 100-year flow event for all of these basins. The excess capacity of the 24" diameter culverts will allow for some accumulation of sediments while still being able to adequately handle the expected flows. The areas of pavement are very small compared to the total area of the watershed subbasins the roads are located within as shown on Figure 3. Table 3 shows the total watershed subbasin area compared to the approximate total roadway area. The roadways make up less than 4.6% of each subbasin. This, combined with retaining as much native vegetation as possible, porous pavements capable of storing and dispersing the stormwater outflow, and the golf course at the base of each subbasin ensures that the stormwater runoff impact from the roadways will be negligible. Table 3. Summary of Watershed Subbasin Areas and Roadway Areas Subbasin ID Drainage Area Roadway Area Area % of Total Subbasin (acres) (acres) (%) 1 47.94 0.86 1.79 2 7.49 0.07 0.97 3 43.29 0.59 0.06 4 55.60 1.00 1.80 5 44.78 2.03 4.53Tr\) 10 Jl ~ lLd CEIVED .f?/1(b l6" . ~_ & r fVwi.J t,.; 'to "..wU JEffERSON COUNTY oen Discovery Bay Golf Course - Grading Permit Stormwater Memo for Road Grading Page 4 of 6 RECEIVED :'i. 1...... ;.. ~_ -.'"'; :",< I"" ..... ;;;i ^ &, precipitation) periods and at doses not exceeding the manufacturer'~~~NrtGU~,D*a to dispose of them at properly approved disposal sites. Any spillage of chemicals or other hazardous materials shall be immediately reported to Jefferson County and the Washington State Department of Ecology. Minimum Requirement #4: Preservation of Natural Drainage Systems and Outfalls. The existing site consists primarily of pervious, landscaped (lawn) areas surrounded by areas of native regrowth. The new graded areas will minimally disturbed, with stormwater runoff being allowed to flow into existing native vegetation as it currently does. The new roadways will be pervious pavements and gravel surfaces, which will not alter stormwater runoff volumes significantly. Minimum Requirement #5: Onsite Stormwater Management. All stream corridors and wetland areas will be protected from disturbance (BMP T5.20). Roadway grading will be integrated into natural topography as much as possible to minimize the grading volumes and utilize existing drainage systems (BMP T5.21 ). Culverts will be used to maintain natural drainage areas across roadways. The culverts will be a minimum of 24" in diameter, which is capable of f10wrates of up to 10 cfs (with inlet control and headwaters at less than 2 feet). Drainage areas calculated for the culverts show maximum 100-yr flood flows of less than 2.7 cfs. See Attachement #2 for culvert design information details. Minimum Requirement #6: Runoff Treatment. The new pollution-generating impervious surfaces (gravel roads) will exceed the 5,000 square foot threshold requiring treatment. Thus, treatment facilities are required for runoff from these paved areas. Treatment from gravel roads will consist of vegetation buffers along the roadways to treat and disperse runoff. Porous pavement (a pervious pollution generating surface) areas will allow for treatment and infiltration as part of their design. Stormwater is treated as it moves through the aggregate road section, and is held in the aggregate until it infiltrates onsite. Minimum Requirement #7: Flow Control. Flow control facilities are required if the stormwater discharges directly into freshwater. Native vegetation surrounds all proposed roadways, allowing for treatment and dispersal of stormwater that does not infiltrate. The porous pavement road sections provide stormwater treatment, storage and infiltration through the aggregate layers in the section. Little if any increase in stormwater drainage is expected since stormwater will infiltrate in the roadway section or in the native vegetation buffers. All stormwater from the roadways will flow down to the golf course, and any remaining stormwater flows that are not infiltrated will be collected in the current drainage areas for the golf course. Areas above the roadways that will drain into culverts will have little development on them, or will be housing lots that will infiltrate all stormwater on the individual lot. WWHM modeling showed that forested conditions produced more runoff than pastured (disturbed forest) conditions for the 100-year storm event. Table 2 shows the culvert drainage areas and their associated runoffs. Figure 2 shows the locations of the culverts and their drainage areas. .{~~~ ~ Discovery Bay Golf Course - Grading Permit Stormwater Memo for Road Grading Page 3 of 6 ]RIE(~ErVED ,,"r' t:' J " ('-' ' f;./ '1, .$.. Table 1. Summary of Cut and Fill Volumes for DBGC's PRRD JUUlU~ COUNTY OLD Road Cut Fill Cut/Fill Road Name Width Road Composition Volume Volume Difference for (negative is (Total) Road for Road fill) (ft) (cu. yd.) (cu. yd.) (cu. yd.) Lawrence Road 22 Porous Pavement 1538.27 1141.14 397.13 Emst Lane 22 Porous Pavement 274.23 125.88 148.35 Emergency Access Road 16 Gravel 843.35 702.39 140.96 Hutson Road 22 Porous Pavement 1609.43 1194.65 414.78 Lily Pond Road 22 Porous Pavement 40.31 2.02 38.29 Bonnie Lane 22 Porous Pavement 172.69 43.38 129.31 Total Volumes 4478.28 3209.46 1268.82 MINIMUM REQUIREMENTS Based on the size and scope of work for the grading project, the project is considered to be "large" in size, and is required to comply with Minimum Requirements #1 through #10. Minimum Requirement #1: Preparation of Stormwater Site Plans. Stormwater site plans have been prepared by 2020 Engineering, Inc. showing the grading areas and erosion control details. Minimum Requirement #2: Construction Stormwater Pollution Prevention. Construction stormwater quality problems are not anticipated since the area will be as minimally disturbed as possible. Newly graded areas will drain into the existing native vegetation following existing drainage patterns onsite. Stormwater pollution prevention measures shall be put in place by the owner/contractor during any site clearing, grading or construction of site improvements. BMPs and methodologies during construction shall follow the guidelines of the SWPPP attached. As appropriate, the SWPPP measures will be located and identified on the civil plans and/or specifications prepared by 2020 Engineering, Inc. The owner/contractor will be required to monitor and maintain the facilities throughout the duration of these site improvements, and will maintain buffers of existing vegetation where possible. Minimum Requirement #3: Source Control of Pollution. As an open space commercial site, minimal source controls are expected to be necessary. The following recommendations shall be implemented to minimize the likelihood of discharging pollutants into offsite drainage systems. · Fertilizers, Herbicides and Pesticides. Owner, maintenance staff and contractors shall be encouraged to store these items indoors or under roofs, to apply them only during dry (non- "",.ll/J.b. 2.... Discovery Bay Golf Course - Grading Permit Stormwater Memo for Road Grading Page 2 of 6 The total area for the project is approximately 200 acres, with slopes onsite varying from 0 to 30%. The golf course area is relatively flat, with less than 8% slope. The majority of residential areas are located up above the golf course area on a plateau, where slopes can range from 15 to 30% or steeper. In general, the site slopes from west to east. Geotechnical investigations for the site have described in general as sandy loam, ranging from extremely gravelly sandy loam to sandy loam with silt and clay deposits. As seen form the attached soil map, most of the golf course area has Type "C" soils mapped. At the lowest point of the property (the proposed drainfield area) the water table was not found in test holes dug in late April. The holes extended down 65 inches to 88 inches. No mottling was seen in the soil profiles. See Attachment #1 for soil maps and data. There are no natural streams, lakes, or ponds on the site. A Class "A" wetland has been identified to the north of the proposed drainfield area. Scope of Grading Work As shown on Figure 1, Lawrence Road will be an 18 foot wide roadway with two foot shoulders on either side (for a total of 22 feet in width) that will be graded from Cape George Road to a looped end in the Highlands area of the site. The road will be approximately 3,740 ft long (including the loop). The roadway is narrower than traditional roadway widths as it incorporates LID design principles (Le., nine foot wide lanes and porous pavement) in order to minimize the amount of grading required at the site. Emst Lane will be a small road off off Lawrence Road, serving the Woodlands area of the site. This lane will use the same 18-foot road section as Lawrence Road, and is approximately 470 feet long. An emergency access gravel road will connect Lawrence Road with Hutson Road will be 12 feet wide, with 2 foot shoulders (for a total width of 16 feet). This emergency road will be approximately 1,090 ft long. Hutson Road will connect the emergency access road to Discovery Road. Hutson Road uses the same 18-foot LID road section as Lawrence Road, and is approximately 3,400 feet long. In the northeast comer of the site, a small 90 foot long access road (Lily Pond Road) and lane (Bonnie Lane) will serve the Lily Pond housing area. These two roadways will use the same 18-foot LID road section as Lawrence Road. Bonnie Lane is approximately 530 feet in length. Table 1 (next page) shows the total cut and fill volumes for each roadway. The maximum cut slope is 2: 1 (typical), whereas the maximum fill slope is 3: 1 (typical). RECEI'TED A! ';~ o. ,"".'" ,. k-.--t i:- JEffERSON COUNTY DGD 12~ ._.o,~.,;.,.""".'~'..~. , ,,1-", '" ,. Memo To: 2020 ENGINEERING, Inc. 700 Dupont Street. Post OffICe Box 1621 Bellingham, WA 98227 USA (360) 671.2020 Fax: (360) 671-0322 R r-.E1r\t' TV [J" www.2020enqineerina.com ~, J All llW lLd _>> Date: August 4, 2006 Public Works Department Jefferson County Mike Asmundson, WeFore, LLC ''. 2 ;." , f' ", L..' C,' ~ . ."Jt. L....... ~. CC: From: Mark Buehrer, PE, Jenifer Ramsey, EIT, 2020 ENGINEERING JfHfASON COUNTY OCO Re: Discovery Bay Golf Course - Grading Permit · Stormwater Management Technical Memorandum For Road Grading The purpose of this memo is to provide a summary of the stormwater management provided for the Discovery Bay Golf Course site for grading a roadway through the development. The proposed scope of work is to grade for a low impact design (LID) roadway, consisting of narrow street widths and pervious pavement. This work will disturb approximately 195,530 square feet (7,700 cubic yards) of soil. Approximately 1 ,270 cubic yards of soil will need to be placed onsite in order to balance the cut and fills. The total amount of paving (porous pavement and gravel roads) is approximately 91,560 sq. ft. Based on this scope of work, the project is determined to be "large" in size, and is required to conform with Minimum Requirements #1 through #10. The following is a summary of the project, scope of work, and how the minimum requirements will be met. Project Summary Discovery Bay Golf Course (DBGC) is an existing privately-owned golf course located on the Quimper Peninsula, approximately five miles south of Port Townsend WA. Originally the site was forested, then converted to homestead pasture and farmland, and eventually a nine-hole golf course in 1925. It was the first public golf course in Washington State. The course was expanded to 18 holes in 1996 with few subsequent modifications. The current owners are pursuing a historic golf preservation plan that is part of a proposed Planned Rural Residential Development (PRRD). The site is located in a rural area outside of the Port Townsend city limits. Development mostly consists of low-density housing and has a rural character, typical of golf courses. The current owners are proposing a minimalist development of a clustered residential community to be tucked into the wooded areas surrounding the course itself. The site consists of eighteen individual tax parcels, which will be vacated upon completion of the final long subdivision plat. Forty-eight new residential lots and one open space reserve that includes the golf course will be created at that time. Eighteen of these lots will have three bedroom cabins constructed on them. t 7-~,._" ,~..."""".,,, ".,,,,,,.. "",' '''''',_,._If!a IZZ, c:.- ~ .-.-. -.--. [fj -.--. ~ ~~~ .--.-. L = F) ~ I,:, C/O en = ~, = t-a tIJ ..../ c-:> ~ = = !;:5 = ~ ~ = en " <::::I c-:> <::::I iJ~ \'\l,-", t.... '~ 'oJ I\'-' 5 \, G) \t~ 0\ m C f~ .. .. 'liJI'" .7 " , ;1 A ;' .,~ j ,.\'..." ~, ..ilIl ~ f Aof '. i'V.._';' ,. d' \ 1 '. ,~"l ' ,/ ,1,' ~ L \ ,;} . ~, ~\ I': '';~:1l 1:li'''';i,,:;'.t' " w'~'" J " ~.' 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'" 0 q c:.-. ~ G) l""'T"'1 '" o~ -T""l ~ -r"l (iJ -0 > '" :x: l""'T"'1 0 ::::x:J Z ~ ':) F) .., ~~ c:=::l '" ~ ~ N:l tTJ qm CJ) c:'"J ~~ - N ~~~ c:=::l ~ ~~ c:::: t'.~ ~ ::i2'::' ... ~'~ 0 ~ "., q rDmG) ,") tIJ )>;:oC t:::::l ~CJ);:o c:'"J Q t:=::I Z::cm :s::mW )>0 -0 '~:A~'/ . /'/ //{" i ( /f . . __,J--"", (1'< 1'- _\\,~ '''-.,----.. . ;;::; II /1 /1 II II (r"" '1 "" ~,--_. \, ~- --.::::: ',,'.. , '-cc;: -c;'~"~~t ~-- \, I ,-J I 9' LANE 18' ROADWAY <t 9' LANE 4: 1 CUT SLOPE (2: 1 MAX) 4: 1 FILL SLOPE (2:1 MAX) 6" POROUS CONCRETE PAVEMENT OR 3" POROUS ASPHALT PAVEMENT 6" - 1 1/4" CHIPPED ROCK BASE RECEr\~/ED i: ! ',l0k .': ~. '(':-i. JEfFERSON COUNTY OeD PROPOSED LOW IMPACT DEVELOPMENT POROUS PAVEMENT SECTION 2' 12' TRAVEL 2' t2.Z- .." ..,.""..."'.>.."'..,.""'...,,".....,,__"'"~~.:',-"""'"~,",.v<...". .,_...,.,.,,,_;.,,,"'.,,~~.o tt:?," ... BENCH BOTH SIDES ~ ~ 4: 1 CUT SLOPE (2: 1 MAX) PROPOSED GRAVEL ACCESS ROAD 4: 1 FILL SLOPE (2: 1 MAX) NOTE: ALL PAVEMENTS THAT MAY PROVIDE ACCESS FOR EMERGENCY VEHICLES SHALL BE DESIGNED TO SUPPORT FIRE TRUCK LOADS. ENGINEER: II. DESIGNED BY: II. BUEHRER DATE: 6-28-06 DRAWN BY: R. KOPKA DATE: 6-28-06 CHECKED BY: oJ. RAMSEY DATE: 6-28-06 PR ,MNGR: II. BUEHRER PROJ, NO: 445dbc FILE NAME: 71 Road s.ct1oM. SCALE: NTS 2020 ENGINEERING, Inc, DISCOVERY BAY SHEET: 700 DUPONT STREET.'PO BOX 1621 BELLINGHAM. WA98227-1621 USA (360}li71-2020FAX(300)671-D122 WVffl'.20ZOenglneeringcom .,..~.....-_........--::-:...::;.-- 1 TYPICAL ROAD SECTIONS Of z o " ~ z r w ~ ~ ~ ~ ~ z ~ o u z o w ~ w ~ ~ w " ~ ~ ~ z " ~ ~ ~ o ~ ~ u ~ o " o ~ o > r t, "!.~. .llHHSOMCOUil Cct III . L II \! IU IJ g .~,- 11- I ~l) I ,.",,,, -"" , j ~ , 'L ~ ~- ~~ 't g " g N g - ~ o , , .' ~l U ,~ '1 , - o ~ i !! " " , . jii . H . z , . il~ 0 j.g ~ i ~ 0' 0 0 . 0 hi g! 0 z ~ . . 10 ~ z of . ~ ~ 0 , . 0' < ~ . ~h ;;; . ~I ~ f N i . U. oc oc :> ~ 0 _ . . 0 i 0 u t ~ ~ z ~j ~ ~:~ H. z ~ ~...J 'i.,," i 0 . _tr ~""O.Q HI 0 . '0 :0 Z _ <\Ie u of '" H~ , z ~ 'f! 0 ~~ ~ i7~U , ~ 'l5 ~ ~ ~ ~ "- U hi -, oc w ~'" ~ Jl~~ ~ H H~ Is jl ~ w h, ~ J! oc 0 ~ '0 0 'I z . " oc " 0 0 oc 0 u ~ ! 0 T 0 c ~ o ii 1! ld I I'/."- 0 oc 0 1"- > Z l.:I 0 It' . ~ H.I.I.8olillllil! I i HIIIIOIIO .00 II1III RECEl \'EiO :'\11) z. .12~~S I I Jmli\ij~,ijU~l1U'U "I L I Hydrologic Group Rating Tables - Hydrologic Group Summary by Map Unit - Jefferson County Area, Washington Soil Survey Map Unit Name Area Map Unit Symbol Rating Total Acres Percent of AOI in AOI Bk Belfast silt loam, wet D 4.9 0.3 variant h D 21.. CeB Casey silt loam, 0 to 8 D 40.7 2.8 percent slopes CfC 111.6 CfD Cassolary sandy loam, 15 to C 7.2 0.5 30 percent slopes emC c CmD Clallam gravelly sandy C 125.0 8.6 loam, 15 to 30 percent slopes ~ ~...... D tti l.t DcC Dick loamy sand, 0 to 15 A 143.4 9.8 percent slopes NBC A 1..9 1$,.3 HuD Hoypus gravelly loamy A 37.5 2.6 ,,,,,Jp~ sand, 15 to 30 percent ", '.,."""'--....,.,-,'~--"".,...,., slopes l"~", HYC ..". A S7.1 3;9 1.... e to 'lRE(~Er\(ED Mm McMurray and Mukilteo D 37.2 2.5 peats Mu D Atl~ 2 ,4 2:.~~ 3'<_ "j. Se Semiahmoo muck D 8.8 0.6 JEffERSON COUNTY oeo 811 D 5.. ..3 t Sm Semiahmoo muck, shallow D 4.3 0.3 variant 8m D It.l USDA Natural Resourc.. _ Conservatioo Service Web Soil Survey l.l National Cooperative Soil Survey 4/6/2006 Page 3 of 4 Hydrologic Group Rating Summary by Map Unit - Jefferson County Area, Washington Soil Survey Area Map Unit Symbol Map Unit Name Rating Total Acres in AOl Percent of AOl TuD Tukey gravelly loam, 15 to 30 percent slopes C 64.5 4.4 Description - Hydrologic Group Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one offour groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration stonns. The soils in the United States are placed into four groups A, B, C, and D, and three dual classes, NO, BID, and CID. Definitions of the classes are as follows: The four hydrologic soil groups are: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (NO, BID, or C/D), the first letter is for drained areas and the second is for undrained areas. Only soils that are rated D in their natural condition are assigned to dual classes. L Parameter Summary - Hydrologic Group Aggregation Method: Dominant Condition Component Percent Cutoff: Tie-break Rule: Lower ft{E(~EIVED AUG 2 4 2n~5 JHffASON COUNTY OCO USDA NaturaJ 11............ _ Cousen'lIlioa Senic. Web Soil Survey 1.1 National Cooperative Soil Survey 4/612006 Page 4 of4 ~ z o ~ G z . w ~ :iI ~ < ~ z ~ o u z o w ~ w " " w " " o > ~ ~ ~ w ~ o w ~~ .. , J~ . ~, " ~, " g ~ 0 J 1J l! '0 , , 'j ~~ , ,- 1'2.'. L !'i 8 " JHHHSOMLOO rroco t II . L I ;1. L f~ It " _m _m z o I- <9 z ::c en ~ <( W 0::: <( ~ z :::> o () z o en 0::: w LL LL W ..., LL o >- w > 0::: :::> en ....J o en z o !;( :IE 0:: o u. Z - D- c( :IE Q) > 00 .- C> ~ ' Q)1ll en~ c: =! o III ~e Illc: ~ . Q)~ ~~ o :;, U.iIl lIl'O Q)1Il ~~ ~~ Q) .. o::~ _ J:: Il:!.:.,j .a 0:: Ill::> Z>. .. Q) ~~ ~:;, _en 0= Q)O Oen ... :;,.Cl ~~ c z w C) W ..J a. <C :E III :I:: c: :> c. 10 :lE III G> '0 :e en () c: o - C> ,5 J:: III ~ ro l!! <( 0 o ~ 8 ..... c: 0 Q) :;'0 t:'! ..... c: U ~ c: Qj ~ ~.....~ I- Q)(tien ::> ~ 1U c: E -'0.2 Q) ..-1U 1i) 1ll0= >. l!!c:c. en <(.2 E Q) >.1Il0 - Q)~U III ~:>c. c: :;,-Ill 'E en~~ 8 .- III = " 00.0 '-' en en en III ~ III ~ g$-6, 8 c7l :I: ~ ~ E s 'iij l!! ~ ~ ~ III -g !!l o 'iij 0:: 0:: .001 t >- .c: c. E!! Ol III G> e lij j ~ ~ in "* "'0 Q) III Q) J:: - c: o "i J:: 0. Il:! g> - o J:: 0. III Q) C> III ,5 (ij 'C: Q) III '0 "'0 Q) III 'C: 0.0 Eo> 00> 0..... - 0...... Ill~ ~<O IZ-Z. ."'''...''''.'~''"'-...,..'_...r''e.'''''''.-'." )€P ....".'c. ,..,.",.,""''''.....,..'.~~" w C. '010 c: E i~... 'a~ ~ Ec:::2 80 lfj ~11l ~Q.1O III ,!a E G> '0 III ,~ ~ G> ;:; ~ 'tij 010'0 III E C G>._ ::l ='0..8 "55:1:: ,- 0 c:: i 6>::l c:: ~ 10 o 10 E c..c_ lOG>O E= c:: ~Ea:: 10 .g :E .c III (j; I!! 0 =~,~ 0'6 E O.?:-G> o.c E _100 o.c III -a,e... o c.:; .c:'01Il 't:G>G> O,!lI ~ G>:I:: 10 ~,g~ JRIE(~E[VIED 1\,,' If'.... ,'" .~ {",j AU ~ i..I ti lUll;':' JEfHRSON COUNTY oeD 8"" ~'O _<'I ~~ o:l '" ~ ~ _CIl ;"0 ..CIl ~.~ ~f! ,- g, ~8 .gu ~.. 6 '.0 o:l Z ~i it I~ ~I Soil Survey of Jefferson County Area, Washington Map Unit Legend Summary Jefferson County Area, Washington Map Unit Symbol Map Unit Name AID liit loam, 0 to & ~ Bk .. Belfast silt loam, wet variant Acres in AOI Percent of AOI 134.5 9.2 4.9 0.3 CeB Casey silt loam, 0 to 8 percent 40.7 slopes ac Oto is 177.6 cm Cassolary sandy loam, 15 to 30 7.2 percent slopes ClDC ~""Oto 179.0 CmD Clallam gravelly sandy loam, 15 125.0 to 30 percent slopes Co ~~- 16.& DcC Dick loamy sand, 0 to 15 percent 143.4 slopes HuD Hoypus gravelly loamy sand, 15 to 30 percent slopes H'\IC Mm McMurray and Mukilteo peats Mu Mutakeo.~ ~ly ~ variant Se Semiahmoo muck Sb SlmiahmoolftWk. m~y shaDow variaat Sm Semiahmoo muck, shallow variant StB 2.8 0.5 HU 8.6 1.1 9.8 37.5 2.6 57.! ),. 37.2 6.3 2.5 0.4 8.8 5.0 IZ2,.. ~,"".', "'." '-",,,~.,,. ,~- .,;>. 'J7 0.6 e.3 4.3 0.3 RECEIVED 3.9 awanteWn~JsaMy~O 19.1 toa,~.,. TuC Tukey gravelly loam, 0 to 15 percent slopes 1\lD Mey ..voll,- ..., IS to 30 perod.... w Water USDA NlIIuraJ Resourc.. iiiiiii Co_nation Servlee 0.3 64.S JEFfERSON COUNW DeD 4.4 0.3 0.0 Web Soil Survey J.J National Cooperative Soil Survey 4/6/2006 Page 3 of4 Soil Survey of Jefferson County Area, Washington Jefferson County Area, Washington Map Unit Symbol USDA Natural Resoun:.. _ Coosenatlon Senke Map Unit Name Acres in AOl Percent of AOl Web Soil Survey 1.1 National Cooperative Soil Survey ",L~~. .. ..~8.,.. R1E(~EIVED i\ ~ :1 '~~; o,~. ~ f't ,",.~,' ,.::Li c,) t-' ':t I.....~_ JEfftRSON COUNTY oeD 4/6/2006 Page 4 of 4 Culvert Model Results Page 1 of 6 WESTERN WASHINGTON HYDROLOGY MODEL V2 PROJECT REPORT DBG Culvert 1 Project Name: Site Address: City Report Date Gage Data Start Data End (adjusted) Port Townsend 7/23/2006 Port Angelis 1948 1993 Precip Scale: 0.80 PREDEVELOPED LAND USE Basin Flows To GroundWater: Basin 1 Point of Compliance No Land Use TILL FOREST: Acres 10.263 DEVELOPED LAND USE Basin Flows To GroundWater: Basin 1 Point of Compliance No Land Use TILL PASTURE: Acres 10.263 Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year ANALYSIS RESULTS Periods for Flow(cfs) 0.033314 0.116123 0.21374 0.396991 0.582279 0.812649 Predeveloped Periods for Flow(cfs) 0.0783 0.203388 0.309667 0.458673 0.574416 0.690527 Developed Unmitigated , , .., 1 "7 2- .~. ".. ..~.k:"""'-F-~""_' 11,- JRIECEIVE 10 /.'1"< () ,"" 1"); ::' ." ')I., ,L",,,"; JHffRSON COUNTY OeD Culvert Model Results Page 2 of 6 WESTERN WASHINGTON HYDROLOGY MODEL V2 PROJECT REPORT DBG Culvert 2 Project Name: Site Address: City Report Date Gage Data Start Data End (adjusted) Port Townsend 7/23/2006 Port Angelis 1948 1993 precip Scale: 0.80 PREDEVELOPED LAND USE Basin Flows To GroundWater: Basin 2 Point of Compliance No Land Use TILL FOREST: Acres 3.267 DEVELOPED LAND USE Basin Flows To GroundWater: Basin 2 Point of Compliance No Land Use TILL PASTURE: Acres 3.267 Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year ANALYSIS RESULTS Periods for Flow(cfs) 0.010618 0.03701 0.068122 0.126526 0.18558 0.259002 Predeveloped Periods for Developed Unmitigated Flow(cfs) 0.024955 0.064822 0.098695 0.146185 0.183074 0.22008 RECEI\~D AUG 2 oi 2~~ JffffRSON COUNTY GC~ Culvert Model Results Page 3 of 6 WESTERN WASHINGTON HYDROLOGY MODEL V2 PROJECT REPORT DBG Culvert 3 Project Name: Site Address: City Report Date Gage Data Start Data End (adjusted) Port Townsend 7/23/2006 Port Angelis 1948 1993 Precip Scale: 0.80 PREDEVELOPED LAND USE Basin Flows To GroundWater: Basin 3 Point of Compliance No Land Use TILL FOREST: Acres 18.819 DEVELOPED LAND USE Basin Flows To GroundWater: Basin 3 Point of Compliance No Land Use TILL PASTURE: Acres 18.819 Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year ANALYSIS RESULTS periods for Flow(cfs) 0.061109 0.213006 0.392064 0.728204 1.068079 1.490646 Predeveloped Periods for Flow(cfs) 0.143626 0.373076 0.568026 0.841348 1. 053656 1. 26664 Developed Unmitigated ,t~~."", 'bJ,.,_, RJECEfVED AUG 2 -4 2UW JHHASON COUNTY DCa Culvert Model Results Page 4 of 6 WESTERN WASHINGTON HYDROLOGY MODEL V2 PROJECT REPORT Project Name: Site Address: City Report Date Gage Data Start Data End (adjusted) DBG Culvert 4 Port Townsend 7/23/2006 Port Angelis 1948 1993 Precip Scale: 0.80 PREDEVELOPED LAND USE Basin Flows To GroundWater: Basin 4 Point of Compliance No Land Use TILL FOREST: Acres 3.509 DEVELOPED LAND USE Basin Flows To GroundWater: Basin 4 Point of Compliance No Land Use TILL PASTURE: Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year Acres 3.509 ANALYSIS RESULTS Periods for Flow(cfs) 0.011397 0.039726 0.073121 0.135813 0.199201 0.278011 periods for Flow(cfs) 0.026787 0.06958 0.105939 0.156915 0.196511 0.236233 Predeveloped Developed Unmitigated r Z. z... ".k"kc... If~,E(~EIVED " ,"'" (, ~ r, ,~ ,,0\,>. ~ ,~ L~i.lJ JEffERSON COUNlY Den Culvert Model Results Page 5 of 6 WESTERN WASHINGTON HYDROLOGY MODEL V2 PROJECT REPORT Project Name: Site Address: City Report Date Gage Data Start Data End (adjusted) DBG Culvert 5 Port Townsend 7/23/2006 Port Angelis 1948 1993 precip Scale: 0.80 PREDEVELOPED LAND USE Basin Flows To GroundWater: Basin 5 Point of Compliance No Land Use TILL FOREST: Acres 10.126 DEVELOPED LAND USE Basin Flows To GroundWater: Basin 5 Point of Compliance No Land Use TILL PASTURE: Acres 10.126 Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year ANALYSIS RESULTS periods for F1ow(cfs) 0.032892 0.114652 0.211031 0.391961 0.574901 0.802352 Predeveloped Periods for Developed Unmitigated Flow(cfs) 0.077307 0.200811 0.305744 0.452862 0.567138 0.681778 -z-Z- . ,,,'J:??_. RECEr\TED .1'," " A f)r' #<'I,.! > ,''1 ./..i"".; JEffERSDN COUNTY DCa . Culvert Model Results Page 6 of 6 WESTERN WASHINGTON HYDROLOGY MODEL V2 PROJECT REPORT Project Name: Site Address: City Report Date Gage Data Start Data End (adjusted) DBG Culvert 6 Port Townsend 7/23/2006 Port Angelis 1948 1993 Precip Scale: 0.80 PREDEVELOPED LAND USE Basin Flows To GroundWater: Basin 6 Point of Compliance No Land Use TILL FOREST: DEVELOPED LAND USE Acres 33.235 Basin Flows To GroundWater: Basin 6 Point of Compliance No Land Use TILL PASTURE: Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year Flow Frequency Return Return Period 2 year 5 year 10 year 25 year 50 year 100 year Acres 33.235 ANALYSIS RESULTS Periods for Flow(cfs) 0.10793 0.376213 0.692466 1.286158 1.886447 2.632788 Predeveloped Periods for Developed Unmitigated Flow(cfs) 0.253672 0.658929 1.00325 1.485994 1. 860972 2.237146 ".l..l::~ 12~> RJECEIVED ~) ,~ i.A' "t JEffERSON COUNiY oeo ~ /'~ /' ~ / :r ~~~/ ; ...~y Q: /~ ~ // W 100 /' ~ /80 ,/' 0 ~ .. 180 J 168 ,submerged 156 C y 144 --, '._0'- J398 0,67 -, 132 ()292 .74 :I 0317 .69 - 120 0 .69 '" 0379 ... .. 0463 ,75 108 .J Q. 0553 .54 .J .. .74 - 96 Q: 0300 :::l ... .0243 .83 0 :::l II: ,0385 .81 84 ...' <11 ,0400 .80 ,0423 .82 "1 Vl al head loss "- 60 (.) ~ 54 2 he full cul- w C> Q: c( '_ G' - 60 /~ 50 / 0 40 /' . .r36 48 42 33 30 27 URBAN STORMWATER MANAGEMENT 10,000 8,000 EXAMPLE 6,000 Oa 36 inCh" 13.0 tIft) 5,000 Q. 66 ct. - 4,000 HW . HW 3,000 0- I'''') (Ii 1,8 ~,4 2,000 (2) 2, , 6.3 (3) 2.2 6,6 .0 jn r..t 1,000 800 600 500 400 300 200 30 ENTRANCE TYPE ~ SCALE o 20 (/) (2) H. 0 d wo; l..._.....co--..'.-. ""1l4Tt;;'d to con lor,., '0 ,'opt '1'6' 8 (3) ProjtClinv 6 5 ro U" ItOlt 121 or (3) prOjt" ~"'" horllontoll1 to ,cal, (I). th.n """"~;""''>Jl.'.. .traight Inclin.d Ii"t ttlrouqh 3 0 a teal... Or "V".. Ot iflultrotld. 2 1.0 _;O~..-- _. 26.15 ( I ) 6. (2) (3) 5. 6. 5. 6. 5. 4. 3. 4. 3. 3. 2. ---""---.... 2. 2. 1.5 1.5 1,5 :r f- a. W o Q: w f- ~ o <t W J: 1.0 1.0 1.0 .9 .8 .8 .8 .7 .7 --~ .5 . ",~ 11, f", ;; P 'f" . ~!ijJ'ib (;; 4 .i.ii..J: HEADWATER DEPTH FOR ;iT~ ~~iTC~~~loN COUNTY U' Culver! inlel conlrol nOlllograph, rr1{W/1. (W'5) FvCtv\l1 ""lp, ~i.'Y /.(j()U Ilc C, fA,.) ~> \4{, 11\ {iV ~{:lt1 () 1 MAINTENANCE REQUIREMENTS DISCOVERY BAY GOLF COURSE DRAINAGE FACILITIES POROUS PA VEMENT · Erosion and introduction of sediment from surrounding land uses shall be strictly controlled after construction by amending the exposed soil with compost and mulch, planting exposed areas as soon as possible, and armoring outfall areas. These surrounding areas shall be inspected regularly and possible sediment sources controlled immediately. · Any utility cuts shall be backfilled with the same aggregate base used under the permeable paving to allow continued conveyance of stormwater through the base, and to prevent migration of fines from the standard base aggregate to the more open graded permeable base material. Small utility cuts can be repaired with conventional asphalt or concrete if small batches of permeable material are not readily available. Clean permeable paving surface after work has been completed. · Clean permeable paving surfaces to maintain infiltration capacity once or twice annually using suction, sweeping with suction or high-pressure wash and suction, but not sweeping alone. · Routine maintenance involves removal of debris that is too coarse to be washed through the pavement system. Vacuuming pavement is required to remove particulates that are fine enough to be carried into the pavement but too large to pass through, thus clogging the void space. Porous pavements require no more repair maintenance than conventional pavements, so maintenance problems can generally be reduced to better "housekeeping" practices on the part of the area residents and more efficient street cleaning procedures in municipalities. · Pervious pavements may have a tendency to clog if improperly maintained. Maintenance procedures include standard vacuum trucks, street sweepers, leaf blowers, and other practices to remove or prevent leaves, needles, or other foliage from collecting in parking areas and streets. Should clogging occur, it usually limited to spot areas. Remedies include localized vacuuming and power washing and, in severe cases, the clogged area may be removed and replaced. · Clogging can be prevented by waiting until all other phases of construction are complete; covering and protecting until all landscaping, topsoil import, or hydro seeding are complete; avoiding areas where any pervious pavement would not be successful; and by regular inspection and preventive maintenance practices. · If spills occur, they shall be immediately vacuumed up followed by a pressure wash or other appropriate rinse procedure. This treatment will restore permeability to almost prespilllevels (95 percent). ,l~?: 1,[; RECEIVED Al,l:~:\ t) t. "'r ,,, ');"d) f.!! ;t. L"",..I JEffERSON COUNTY DCO <( JEFFERSON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT RECEf'\TED if r' , ~ '1l 621 Sheridan Street. Port Townsend' Washington 98368 360/379-4450 . 360/379-4451 Fax http://www.co.jefferson.wa.us/commdevelopmentl Stormwater Calculation Worksheet oS-2BCo MLA# PROJECT/APPLICANT NAME: JffffRSQJijOO~TY OEDI .,..JZC:k... ~}. Golf Club 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 fI.E.. SITE) Size of parcel ~:J.. 00 acres An acre contains 43,560 square feet. Multiply the acreage by this figure. Size of parcel in square feet tI, '7 (Z 1000 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, excavated, and/or compacted for proposed development project, Include in this calculation the area to be cleared for: Construction site for structures ,v/~ sq/ft Drainfield, septic tank, etc, .#/~ sq/ft Well, utilities, etc. IJ./A sq/ft Driveway, parking, etc. /(//~ sq/ft Lawn, landscaping, etc. N/A sq/ft ( /?at:tdwa y. ). . I?B./4l!? sq/ft Other compacted su ace, etc. . Total Land Disturbance /9~ ,/9B sq/ft [over] stonnwater calc worksheet doC - REV, 10/1212003 Answer the following two questions related to conversion of native vegetation: Does the project convert % acres or more of native vegetation to lawn or landscaped areas? Circle: @ Yes Does the project convert 2 Y2 acres or more of native vegetation to pasture? Circle: ~ Yes Indicate Total Volumes of Proposed: Cut ~L./7/1; C. i. Fill ~, 7,()Q (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 CALULATIONS -IMPERVIOUS SURFACE EXISTING (1v111/fN /lOA/) WtI/2-fC.. ?1M Irs ) N/,q sq/ft . /V/4 N/t; . ;V/4 . A1/~ )VIA t::) NEW f./!A f.//4 #/4 fJlFJ Driveway N /11 Other 6'1z;~~..,t,.,eI'€J 11,t/LID Total New I~ Lfl/o Structures (all roof area) Sidewalks Patios Solid Decks (without infiltration below) TOTAL NEW + TOTAL EXISTING* sq/ft Structures (all roof area) sq/ft sq/ft sq/ft sq/ft sq/ft sq/ft /7, f./tfO sq/ft "This amount will be used to check total lot coverage. DEVELOPMENTv.REDEVELOPMENT sq/ft Sidewalks sq/ft Patios The following questions will help determine whether the proposed project is considered development or redevelopment. sq/ft Solid Decks (without infiltration below) sq/ft Driveway sq/ft Other sq/ft Total Existing Divide the total ~ impervious surface above by the size of the parcel and convert to a percentage: Does the site have 35% or more of existina impervious surface? Circle: Yes () % ~ 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 jS~~'T~~e or prepare a Stormwater Site Plan using the step-by-step guidance in the Stormwater Management Manual. '-- '... ,",' . "'" APPLICANT SIGNATURE .' ..JJ:~~,....._-"....- By signing the Stormwater Calculation Worksheet, I aDe~t4ciGIrl\l'JQ~Qt the information provided herein is true and correct to the best 7Jijedge. I also ceotify thlIt u:fWii~n ~ .;Jli11flh.;!ie _ the full knowledge and consent of aI owner the aflected po"". .Jo ~ ..... 2 - ",,"r" -it I ~ L_~,.J ~ ~c./ 0b AUTHORIZED REPRESENTATIVE SIGNATURE) (DATE) / slormwaler calc worksheel.doc - REV, 1011212003 2