Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Preliminary Drainage Report
o .1~I"t~Inc. Civil Engineering & Surveying PRELIMINARY STORM DRAINAGE REPORT FOR THE AUTUMN HILL PLAT MAY 2001 PREPARED FOR: PAUL LUBBESMEYER LUBBESMEYER CONSTRUCTION 1151 E. 112TH STREET TACOMA, WA 98445 (253)-537-6370 PREPARED BY: ANNA M.-B. HOLT, PROJECT ENGINEER C.E.S. NW, INC. 5308 12TH STREET EAST, SUITE B FIFE, WA 98424 (253) 922-1532 PROJECT No. 00133.0 5.25.2001 PRELIMINARY STORM DRAINAGE REPORT FOR THE Autumn Hill Plat Yelm, Washington May 2001 Prepared for: Paul Lubbesmeyer Lubbesmeyer Construction, Inc. 1151 East 112th Street Tacoma, WA 98445 Prepared by: _-~ Anna M.-B. Holt, Project Engineer , y' Approved By: ~ ~~c~~~ ~r~~~ L;~w ~~S Seabrook M. Schilt, P.E., Principal ~~w~,~. REPORT #00133 "I hereby state that this Preliminary Drainage Report for Autumn Hill has been prepared by me or under my supervision and meets the standard of care and expertise which is usual and customary in this community of professional engineers. I understand that the City of Yelm does not and will not assume liability for the sufficiency, suitability or performance of drainage facilities prepared by me." This analysis is based on data and records either supplied to, or obtained by, C.E.S. NW, Inc. These documents are referenced within the text of the analysis. The analysis has been prepared utilizing procedures and practices within the standard accepted practices of the industry. TABLE OF CONTENTS PAGE STORM DRAINAGE ................................................................................................................................................2 1. PROPOSED PROJECT DESCRIPTION ....................................................................................................................2 2. EXISTING CONDITIONS ......................................................................................................................................4 3. INFILTRATION RATES/SOILS REPORT ................................................................................................................4 4. WELLS AND SEPTIC SYSTEMS ...........................................................................................................................5 5. FUEL TANKS .....................................................................................................................................................5 6. SUB-BASIN DESCRIPTION ..................................................................................................................................6 7. ANALYSIS OF THE 100-YEAR FLOOD .................................................................................................................6 8. AESTHETIC CONSIDERATIONS OF THE FACILITIES ..............................................................................................6 9. FACILITY SIZING AND DOWNSTREAM ANALYSTS ...............................................................................................7 10. COVENANTS, DEDICATIONS, EASEMENTS .....................................................................................................8 1 1. PROPERTY OWNERS ASSOCIATION ARTICLES OF INCORPORATION ................................................................8 12. OTHER PERMITS OR CONDITIONS PLACED ON THE PROJECT .........................................................................8 AppendixA General Exhibits Vicinity Map ........................................................................................................................ A-1 Thurston County Geodata Parcel Map ................................................................................. A-2 Soil Conservation Service Soils Map and Description ......................................................... A-3 Curve Number Selection Table (DOE Table III-1.3) ........................................................... A-5 Design Storm Precipitation Values Isopluvial Maps ............................................................ A-6 Alpha Design Soil Study ...................................................................................................... A-9 Appendix B Basin Exhibits Developed Basin Map, 11 x 17" .......................................................................................... B-] Thurston County Geodata Topography ................................................................................ B-2 Appendix C Storm Water Calculations (Also See Work Map) Storm Shed Computer Analysis Printouts ............................................................................ C-1 Bioswale Calculations .......................................................................................................... C-3 Preliminary Plat Plan ............................................................................................................ C-4 P:.00133 ~.ReponPrcli m.Oi.O l .doc STORM DRAINAGE 1. Proposed Project Description This report accompanies the preliminary plat plans for the Autumn Hill private residential project as submitted to the City of Yelm. The site information and the analysis used for sizing of the preliminary stormwater quality treatment and conveyance systems are included within. The Autumn Hill Plat consists of 26 single-family lots situated on a parcel approximately 6.64-acres in size. The subject project site is made up of two rectangular shaped parcels located on Vancil Road within the city limits of Yelm, Washington. The City of Yelm Development Guidelines establishes the methodology and design criteria used for this project. All storm drainage design has been done according to the City of Yelm Development Guidelines, the City of Yelm Public Works Standards and the Washington Department of Ecology Stormwater 1l~Ianagement Mamral fo~° the Puget Soarnd Basin. Permit Applied for: Preliminary Plat Address: 10831 & 10847 Vancil Road, Yelm, WA Legal Descriptions: Parcel 1: The South 116 Feet of that Part of the Southeast Quarter of the Southwest Quarter of the Northeast Quarter of Section 30, Township 17 North, Range 2 East, Willamette Meridian, Lying South of the South Lateral of the Yelm Irrigation District Ditch, Excepting Therefrom the East 363 Feet; and Excepting Therefrom the County Road Known as Vancil Road Along the East Boundary; Together with the North Half of the Northeast Quarter of the Northwest Quarter of the Southeast Quarter of Section 30, Township 17 North, Range 2 East, Willamette Meridian, Excepting Therefrom the North 64 Feet of the East 363 Feet; and Excepting Therefrom the North 64 Feet of the East 363 Feet; and Excepting Thereform the County Road Known as Vancil Road Along the East Boundary. Parcel 2: The East 363 Feet of the South 116 Feet of that Part of the Southeast Quarter of the Southwest Quarter of the Northeast Quarter of Section 30, Township 17, North, Range 2 East, Willamette Meridian, Lying South of the South Lateral of the Yelm Irrigation District Ditch, Excepting Therefrom the County Road Known as Vancil Road Along the East Boundary; Together with the East 363 Feet of the North 64 Feet of the North Half of the Northeast Quarter of the Northwest Quarter of the Southeast Quarter of Section 30, Township 17 North, Range 2 East, Willamette Meridian, North Half of the Northeast Quarter of the Northwest Quarter of the Southeast Quarter of Section 30, Township 17 North, Range 2 East, Willamette Meridian, and Excepting Therefrom the County Road Known as Vancil Road Along the East Boundary. In Thurston County. The proposed development shall be accessed via Vancil Road. A bioswale and infiltration system located near the entrance to the plat will provide stormwater quantity and quality control for the proposed public road, driveways and proposed roofs. Stormwater drainage facilities will be installed to collect and convey stormwater from Basin `A' to the proposed bioswale located on the storm tract. Basin `A' is 6.64 acres in size. The basin consists of the }public road, all new driveways, and roof and yard runoff and public road improvements (see Basin Map, Appendix `B'). After flowing through the bioswale, the stormwater will enter the infiltration pond and discharge to the groundwater. Since all stornl water will be collected and infiltrated onsite, Autumn Hill Plat flows contributing to offsite drainage basins will be reduced to less than existing conditions. 2. Existing Conditions The proposed project site is comprised of two parcels totaling 6.64-acres in size. Currently, the parcel is mostly pasture. However, there are two existing residences with associated outbuildings, driveways and landscaping on the parcel, which will be removed prior to the plat's installation. The site is bordered on the north and south by single- family residences, and to the east and west by single-family residences and undeveloped land. Vancil Road borders the parcel on the east side. This property will be accessed via a public road connecting to Vancil Road. Topographic fieldwork conducted on the subject parcel has determined existing grades to be between 0.5% and 6%. The site is relatively flat and the underlying soils are Spanaway gravelly sandy loam, which is in a Type `A' soil group. Contributing offsite flows onto the site are negligible since the project and surrounding areas are mainly flat and with gravelly soils (see Basin Map, Appendix `B') 3. Infiltration Rates/Soils Report The Soil Conservation Service Survey of Thurston County identifies the soils onsite as Type 110, Spanaway gravelly sandy loam. An infiltration study was performed by Alpha Design Service, which supports this soil classification (see Infiltration System, Soil Evaluation Report -Appendix `A') Textural analysis was performed to determine if infiltration of storm water was feasible. It was determined from the testing that the site would support infiltration. The Alpha Design Soil Evaluation Report lists the site percolation rate as 1" per minute, which is 4 60"/hour. It is important to point out that a design infiltration rate of 20"/hour was used to size the infiltration system. This is a safety factor of 3, which exceeds the Stormwater Management Manual for Western Washington Volume III required safety factor of 2 for this soil type. 4. Wells and Septic Systems The project is located in the City of Yelm water service area. The public water main ends at the north property line and will be extended to serve the developed project. The project is not connected to the public water system at this time. There is an existing well located in an outbuilding behind the existing house on parcel No. 22730130900. The existing well will be abandoned per City of Yelm, Thurston County Health Department and Department of Ecology regulations. Parcels north of the site are connected to the public water system; therefore, it is assumed that no wells are present on those parcels. The parcels to the south of the project are probably served by wells; however, the closest offsite structure is greater than 200 feet from the project boundary. The existing residence has a septic system, which will be abandoned in accordance with the Thurston County Health Department. Public sewers will serve the new lots. 5. Fuel Tanks There are no known fuel tanks on or within 200' of the site 5 6. Sub-Basin Description Basins The existing site basin is topographically situated so that offsite flows contribute a negligible amount of stormwater runoff to the proposed site. The site is located in an area mapped as gravelly sandy loam. Under developed conditions, Basin `A' which is 6.64-acres in size, will be collected and conveyed to the onsite bioswale and infiltration system. Basin `A' peak flow for conveyance calculations is 2.091 c.f.s. for the 100-year, 24-hour storm event. The 100- year, 24-hour and the 100-year, 7-day storm events were analyzed to size the proposed infiltration system. The 100-year, 7-day storm event turned out to be the governing storm event. The conveyance calculations have been included in Appendix `D'. 7. Analysis of the 100-year Flood The site does not lie within a known flood plain. 8. Aesthetic Considerations of the Facilities The infiltration system and bioswale has been located near the entrance to the plat and will be landscaped in accordance with City of Yelm standards. The conveyance system will be subsurface and out of eyesight. The bioswale cover will be grass, and will blend into the proposed landscape features. G 9. Facility Sizing and Downstream Analysis Facility Sizing Storm water analysis calculations are included in Appendix `D' of this report. The proposed basin area was developed into one 6.64-acre area to determine the runoff rates for the 100-year, 24-hour storm event and the 7-day, 24-hour the basin. Assumptions and data used for developing the hydrology for the site are as follows: Methodology: Rainfall Distribution Runoff parameters: Rainfall intensity: Runoff Curve Numbers SBUH Type 1 A storm event Pierce County 7 day stornz event for infiltration Soils -Gravelly Sandy Loam See Isopluvial Maps in Appendix A 6-month storm event = 1.58 inches/24-hour 10-year, 24-hour = 3.00 inches/24-hour 100-year, 7-day = 12.00 inches/7-day 100-year, 24-hour = 4.10 inches/24-hour Post-developed CN = 86.08 Impervious areas CN = 98 Lawn areas CN = 77 7-Day Adjusted CN = 76.40 The 100-year, 7-day storm and the 100-year, 24-hour storm event were both analyzed to size the infiltration system. Since Yelm is adjacent to Pierce County and the 100-year, 24-hour storm event is similar to that of Pierce County, and in the absence of Thurston County data, the 100-year, 7-day storm analysis was completed using Pierce County 100- year, 7-day storm data. The 100-year, 7-day storm event created a greater volume of stone water; therefore, this event was used to size the infiltration pond. The 100-year, 7 24-hour Type lA storm event will be used in considering pipe conveyance capacity. The 6-month storm will be used to size the biofiltration Swale. Detailed calculations will be provided at the time the site development plans are submitted. All new road and driveway runoff from the Autumn Hill Plat will be treated prior to being discharged into the proposed infiltration system. Downstream Analysis Since the site is discharging to an infiltration facility, downstream conveyance is not an issue. The down stream corridor was analyzed to determine the area that would be impacted if the infiltration system overtopped during a 100-year storm event. The area that would be impacted is the adjoining parcel south of the project and Vancil Road. 10. Covenants, Dedications, Easements Utility easements will be provided as necessary. 11. Property Owner Association, Articles of Incorporation A Homeowners Association will be established prior to final plat approval. The Articles of Incorporation will be provided to the county for approval upon submittal of the final plat. 12. Other Permits or Conditions Placed on the Project None know at this time. C.E.S. NW, INC. ,~1717Q H~)jl Project Ef~gineer APPENDIX A Storm Water Calculations Vicinity Map Thurston County Geodata Parcel Map Soil Conservation Service Soils Map and Description Curve Number Selection Table (DOE Table III-1.3) Design Storm Precipitation Values Isopluvial Maps Alpha Design Soil Study A-1 A-2 A-3 A-5 A-6 A-9 C.~'.,s. NWInc. Autuinri Hill Preliminary Plat Civil E~7ginecrine & Sun~ering 5305 12th Street East Business: (253)922-]532 ~~ ~ S uite B ~ Fax: (253)922-1954 Vicinity Map Fife, WA 954_4 ceservices@gwest.net ~3 N Not to Scale ~ ..aN,tt ;~a.. ,,. ~~ x. ... .j .,. . J h .!3. U,M.^:; 1. .i ,S ~JVt;t ~ .n .t llr~ . ' ~JI~V: . ~ ~~ t fiU) `,~ 4 : . ~a.. .l C~'1 <rv~ , ry ~ r ... My '(T ~: C. yi ©L } t .i; , ~`~ iF • ( ,U ~ ~ , , ~ .` Fl+ilvh ~, y&., 7 ~`4, ~ s µ' et ~' i t i-~- x~^ ~ ;,~ ,v u~ , ° ':F •K. 4, 5 { t~' .. ~ . ~ 'Y Yr 1 .' R~ N, J i .I? ~A, V'1 t d I :~/ ry Y t ,0.t s~„"I 1. ,,, ^~` y a F*y. c F ~~ r . J yv> ~ Y '``'~ `~ ~ ~~`~ l'~+' ~ '~ - f , x ~ avt rya .a 11~~t~iNi ~.a ^ 4~"Ni .r1..7 t... ., t, F `'F .,vt i' r~ } }} ~~/5l ` ~ ; ' ~ . ~ . r, `` n ~ 50n ~ art itl5 FIJVfi. .~ `~ ~ ' r , u ur n: art . r' - . . ~, J. ~ n fit ~ 'l a, ~^ t ~)t~!~ [a .a.< t f'%?1111 ': 2 ~ I ! a ~i , `` l ` G ' .... W ,, ,, ,isrirf ~ ti,~ «> ~ tr;.litfll l;il:S: ~ o . Q - 'fi; :I! n:,F .I (~~ 'IJ7il AVi~' `;[. r, 1~ „~ ~~'~~ ~~ Site '~ . ~~ ,.1. ~~ ~~ -~ W ~, 2J ~ ~-( - r .T~" ~ uJ '~ ,;t~ Y T17N ~' " ; ~, h~1ap by R~)adrunner Maps r~ ~ 949 C. ~. ~. NW Inc. I Autumn xill /.a - Z Civil Engineer"1J1a Services Vicinity Map C.~'.-S. NWInc. Autumn Hill Preliminary Plat Civil Engineering & Surnc~t•ing X308 12th Street East Business: (253)922-1532 ~-3 suite B Fax: (253)922-1954 USDA Soil Conservation Service Soil Map Fife, WA 98424 ceservices@gwest.net N Not to Scale ~ ~a, .,, 119 i 1 ; , • ,<ry'?~ .. 712' ' a~3,'"v' ma=y,' °,s.~; '.6 ~IQ, t `d1{1.'. `t a~ ~:d9. S `~; ~,,:4 rob' : ~, :t N~ ' za '4 '<+^;S .Yf~ ~ " y. _ .2'~ ~' a . ~ ~'<x.''. X~ '~ ~ ~ ,~, m: is " .~, ~ f3':~:}, °. •& ~~ 6•S.. ~ Y ~ ~' .Fa ~ ~ ~ Y~~.. ~ b y~,~~ >~F' F g ~ Y• j ~~ ; 111 ~~.. s '. `SI'9 ;~'^~~ "IIQ...° Q0., •~.; ;~ u r ,. .~, ~ Came ' m..4 ~ ,I1 tz ~s ~ a e 1! k F, . F$.,~;~ .~.. ~c~g z^° Vi ti 9~i~b?,~ {~ ~ ~ 111 ~2'~ a'~° .l~s•~,, It3 y 6 ia~ ~' Sit Ha rt» - :;,ia - s'~ e. ~ s va sc~:}y.:<D ~'.~.,,'~'r'"}'+.'"4i~:3.` _,~,.x'. , -,. ex s,C~Lo ~,~'-k \ ~,y . _Y~~•x ~?~ CFT.r{$A .?y 4. F^a:.~ g,-;, 1-~'~.~ •~ '~., Aa 3;;~' sa: ~';P `°" ";~' "rya: '.x, ~^ ~ .~h II ~ ~ ~ w *. ~,~ ;1'13 "'. 33.. ~~~ ~ „~•x a ~hb.}.6iyt i».Ib~ ~y~g~Yp ~~ Y \d'~~ ~ ~ . w 'h: ' "r~~S. § ~•:k.;,.~r y°? ~* ~ t ~ ~ .`'°•"` 112.. r 'r ,~° +~' i : ` _ •~~,3°"d,'." >w~~ .;,~~ 113. , n, d ~ ~."~".. ', r~" ..,r,' ~ .~'-`.~'• .. 5t1 tt, •.1srw ',o ass ,,.,..f g .. ~-,- "~ ` "'. ~"- v;: 113- .. ~° 76 ~ e, ,tom; ,~^>'~,'~ ~\tap by USDA Suil Conscrcation Scr~icci 1970 C.E.S. Nwlnc. Ciril Engineering & Surnc~~ing 5308 12th Street East Suite B Fife, WA 98424 Business: (253)922-1532 Fax: (253)922-1954 ceservices@gwest.net Autumn Hill Preliminary Plat -~ USDA Soil Conservation Service Soil Description 110- Spanaway gravelly sandy loam, 0 to 3 percent slopes. This very deep, somewhat excessively drained soil is on terraces. It formed in glacial outwash and volcanic ash. The native vegetation is mainly grasses, ferns, and a few conifers. Elevation ranges from 100 to 400 feet. The average annual precipitation is 45 to 55 inches, the annual air temperature is about 51 degrees F, and the average frost-free period is 150 to 200 days. Typically, the surface layer is black gravelly sandy loam about 15 inches thick. The subsoil is dark yellowish brown very grav- elly loam about 5 inches thick. The substratum to a depth of 60 inches or more is dark yellowish brown extremely gravelly sand. Included in this unit are small areas of Alderwood soils on till plains; Everett, Indianola, and Nisqually soils on outwash ter- races; and Spana soils in depressions. Also include are small areas of Spanaway soils that have a stony sandy loam surface layer and small areas of Spanaway gravelly sandy loam that have slopes of 3 to 15 percent. Included areas make up about 20 percent of the total acreage. Permeability is moderately rapid in the subsoil of the Spanaway soil and very rapid in the substratum. Available water capacity is low. Effective rooting depth is 60 inches or more. Runoff is slow, and the hazard of water erosion is slight. This unit is used mainly as hayland, pasture or cropland, as a site for homes, or as a source of gravel. It is also used as wood- land. The main limitation affecting hay and pasture is the low availability of water capacity. Proper grazing practices, weed control, and fertilizer are needed to ensure maximum quality of forage. Rotation grazing helps to maintain quality of forage. Periodic mowing helps to maintain uniform growth, discourages selective grazing, and controls weeds. Animal manure can be applied periodically during the growing season. Areas that receive heavy applications should be harrowed at least once a year. In sum- mer, irrigation is needed for maximum production of most forage crops. Sprinkler irrigation is the best method of applying wa- ter. The amount of water applied should be sufficient to wet the root zone but small enough to minimize the leaching of plant nutrients. This unit is suited to crops. Wheat, oats, strawberries, raspberries, blackberries, and sweet corn are commonly grown. The main limitation is the low available water capacity. In summer, irrigation is needed for maximum production of most crops. Sprinklers can be used, but a slow application rate is needed to minimize runoff. The amount of water applied should be suffi- cient to wet the root zone but small enough to minimize leaching of plant nutrients. The application rate should be adjusted to the available water capacity, the water intake rate, and the needs of the crop. Animal manure can be applied periodically during the growing season. Areas that receive heavy applications should be harrowed at least once a year. This unit is well suited to homesites. Pebbles and cobbles should be removed, particularly in the areas used for lawns. In sum- mer, irrigation is needed for lawn grasses, shrubs, vines, shade trees, and ornamental trees. Mulch, fertilizer, and irrigation are needed to establish lawn grasses and other small-seedgd plants. The main limitation affecting septic tank absorption fields is a poor filtering capacity. If the density of housing is moderate or high, community sewage systems are needed to prevent the contamination of water supplies caused by seepage from onsite sew- age disposal systems. Cutbanks are not stable and are subject to sloughing. Douglas fir is the main woodland species on this unit. Among the trees of limited extent are Oregon white oak, lodgepole pine, and red alder. Douglas fir and Scotch pine are grown on Christmas tree plantations. On the basis of a 100-year site curve, the mean site index for Douglas fir is 140. On the basis of a 50-year site curve, it is 108. The highest average growth rate of an un- managed, even-aged stand of Douglas fir is 145 cubic feet per acre per year at 65 years of age This soil is suited to year-round logging. Unsurfaced roads and skid trails are slippery when wet. Logging roads require suit- able surfacing material for year-round use. Rounded pebbles and cobbles for road construction are readily available in this unit. Disturbance of the protective layer of duff can be minimized by the careful use of wheeled and tracked equipment. Seedling establishment and seedling mortality are the main concerns in the production of timber. Reforestation can be accom- plished by planting Douglas fir seedlings. if the stand includes seed trees, natural reforestation by Douglas fir, Ore~~on white oak, and lodgepole pine occurs periodically in cutover areas. Doughtiness in the surface layer reduces the seedling survival rate. When openings are made in the canopy, invading brushy plants can delay the establishment of planted Dou~~las fir seedlings. Common forest understory plants are cascade Ore~~on grape, salal, western brackenfern, western swordfern, Indian plum and scotch broom. This map unit is capability subclass IVs. Table 1.3 Runoff curve numbers for selected agricultural, suburban, and urban areas (Sources: TR 55, 1986, and Stormwater Management Manual, 1992) CNs for hydrologic soil group Cover e and h drolo is condition ..................................................................................A B C D Curve Numbers for Pre-Development Conditions Pasture, grassland, or range-continuous forage for grazing: Fair condition (ground cover 50% to 75% and not heavily grazed) ......................................49 69 79 84 Good condition (ground cover >75% and lightly or only occasionally grazed) ...................39 61 74 80 Woods: Fair (Woods are grazed but not burned, and some forest litter covers the soil) . ...................36 60 73 79 Good (Woods are protected from grazing, and litter and brush adequately cover the soil)..30 55 70 77 Curve Numbers for Post-Development Conditions Open space (lawns, parks, golf courses, cemeteries, landscaping, etc.)' .............. Fair condition (grass cover on 50% - 75% of the area) ........................................................ 77 85 90 92 Good condition (grass cover on >75% of the area) ...............................................................68 80 86 90 Impervious areas: Open water bodies: lakes, wetlands, ponds etc. ] 00 100 100 ] 00 Paved parking lots, roofs, driveways, etc. (excluding right-of--way) ................................................. 98 98 98 98 Streets and roads: Paved ...................................................................................................................................................98 98 98 98 Gravel (including right-of--way) .......................................................................................................... 76 ~ 8~ 89 91 Dirt (including right-of-way) ............................................................................................................... 72 82 87 89 Pasture, grassland, or range-continuous forage for grazing: Poor condition (ground cover <50% or heavily grazed with no mulch) ...............................68 79 86 89 Fair condition (ground cover 50% to 75% and not heavily grazed) ......................................49 69 79 84 Good condition (ground cover >75% and lightly or only occasionally grazed) ...................39 61 74 80 Woods: Poor (Forest litter, small trees, and brush are destroyed by heavy grazing or regular burning) ...................................................................................................45 66 77 83 Fair (Woods are grazed but not burned, and some forest litter covers the soil) .....................36 60 73 79 Good (Woods are protected from razing, and litter and brush ade uatel cover the soil)...30 55 70 77 Single family residential : Should only be used for Average Percent Dwelling Unit/Gross Acre subdivisions > 50 acres impervious areaz,s 1.0 DU/GA .............................................................................................. 15 Separate c urve number 1.5 DU/GA .............................................................................................. 20 shall be sel ected for 2.0 DU/GA .............................................................................................. 25 pervious & impervious 2.5 DU/GA .............................................................................................. 30 portions of the site or 3.0 DU/GA .............................................................................................. 34 basin 3.5 DU/GA ...................................:.....x................................................... 38 4.0 DU/GA .............................................................................................. 42 4.5 DUIGA .............................................................................................. 46 5.0 DU/GA .............................................................................................. 48 5.5 DU/GA .............................................................................................. 50 6.0 DU/GA .............................................................................................. 52 6.5 DU1GA .............................................................................................. 54 7.0 DU/GA .............................................................................................. 56 7.5 DU/GA .............................................................................................. 58 PUD's, condos, apartments, commercial %impervious Separate curve numbers shall businesses, industrial areas & must be be selected for pervious and & subdivisions < 50 acres computed impervious ortions of the site For a more detailed and complete description of land use curve numbers refer to chapter two (2) of the Soil Conservation Service's Technical Release No. 55 , 210-VI-TR-55, Second Ed., June 1986 . ' Composite C~]'s may be computed for other combinations of open space cover type. 'Assumes roof and drive~eay runoff is directed into street storm s}stem. '~'herc roof runoffand drive runoff are infiltrated or dispersed according to the requirements in Chapter 2, the average percent impervious area may be adjusted in accordance with the procedure described under "Flo~~ Credit for Roof Uo~~nspout lntiltratioti ~ and "Flow Credit for Roof Downspout Dispersion" in Chapter 2. -[u,t,~rcc/ ?U(1(J ['olrrnre /II - Ht~clrolo,t~ic• : [rralt~sls arrcf Flntt~ C'onU•ol De.cigrr Page 33 l~ Western Washington Isopluvial 2-year, 24 hour 124 123 ~~~ '" 9 25 25 25 >o ;w m b+o~s ~sb ssbis ~o ssmuis x tom-- - ,~ o ~ ~ - i ~ BE Z ~ r~ OLGA s ` ~ _ ~ v ~ ~ 1> FRIDAY HARBOR PORT STA LEY _ ~ MT.: ~ l 4 () jam. \ ~ ~ 5 ATE! 1--4~// r X35 - - ~ 25 `-~~ ~~ ) JO •~oENT ~II ~n A A 35 3 2 L ~ s ~ 3(45 s ~ ~ ~z. O 5 1 -+ 20! a v~ ~ ~ 3 25 ~~-- ISOPLIlVIALS 2-YR 24HR PRECIPITATI N fN TENTHS OF A NCH 124 i ~s ~ « ~.., Ye~m _ 2- r Z~ -~+r etltnf = 2.2 inches ~m~~l~l l~s~~t~ 72 / a~ ~ r~vS~r~I = /• 5s lrsG6tGS Puge ;'<Y G~olil)1ac~ 111- Hydrologic.-~nu(isis arad Flnr1• Cnrrtrn~ Desig~t .4ttgtist 2000 /~ Western Washington Isopluvial 10-year, 24 hour .-lzr~~irst Z(100 6~c~lume /II - H~•clr•o1~~,~~ic.=l~7uh~sis urad Flotit• Co~ztrol Desi~r~ Page 79 "" iaa~xsa~na~t urroaw~ac mom sr. ~arw, rz.~nt ~~~~ ~ ~o.~~ z9-h~ ~ve~ ,: 3 . o ~~ch~5 ~su.zcs«.taww wroae~a cvrru~ rt. woRn~, rnana • e!m -~ ~~ - ~Y ~ -Gtour eves= ~• 1 ~~~~ y Puge ~0 6'~~lu»~e III - Hrc~rol~~,t'ic .~1 ~~uh~sis zmd Flotir Cr~r9U•ol Desig~r .~1 u~~arst tuvv ~h _ S . Western Washington Isopluvial 100-year, 24 hour From:CES NW 1NC. 253 922'1954 PRttAllllt: RLEABE RlADALL IN>lTRUCTION$ FIRST 04/ 10/2001 08:27 #OG7 P .004 8TAF1' U9E ONLY BOIL gW1lUAT10N REPORT RORM Z: 801E LOO INFORMATION PROdLCTTITi.E: SHEET; 1 OF 5 - PRpJIGT N0. :~ DATE : PREPARED 8Y 801LLOQ : ~ see SEE ATTACHED MAPPING LOCATION: . 1, TYPES OF TESTS Z SCS SOIL SERIG8: 3. lANO FORM: DONE:BACKNOE SPANANAY 6RAYELLY LOAM OUTNASH PLAIN ERCAVATEO SOIL 4. Ogp0191T10N. Q. HYDROIOQIC SOIL OROtJP: 6. OHPTH TO SEA90NAl HIDH WATER: HISTORY: ~ A 144" + OUTiIASN 7, CURRENT WATER 8. DEPTH TO IMPERVIOUS LAYER; 0. M18C: Ogpn{; SITE 1S CLEAR PASTURE N 144 + 144"+ LAND .. TMO SMALL HOUSE AND A BARN TO BE REMOYED..SLOPES00-5~ '10. POTENTIAL. FOR: 1aR0810N itUNOFF PONOINO ' NONE MINOR NONE ' 11, SOIL, PRORLIg DEBCIVPTION: HORZ QEPTH 'TEXi'UR6 KCI. $TR MOT IND Rdd fX) A8P SLN1 A 00-15"j' BLACK LOAM 10 N N 15" A 15-40'f~ LOAMY SAND ' AND GRAVEL Q N N 48" B 15-144" COARSE SAND AND GRAVEL W/ EOBBLES 4 N N N 12. BREPE!lCOlAT10NRATle: 1" PER MINUTE . '1 ~.'pIN01N088AECOMMlNIal1T10N8: DONNSPOUT BLOCKS STORM POND/6ioswale far road storm water ~. F-4 ~_ r, J ~~Gld I~IH~S:~ ~GG,% 9Z 'adt-J BE~~~~S~STb 'GhJ ~hJUHd ~J~~~Od QdHH~~I~J u~r.a~ From:CES NW INC. 253 922'-1954 PRlUAR'l.R.' PLEABE RlAD All (NaTAUCTI0N9 FiRBT U4/ l0/2001 03:27 #067 P .004 8TAFF USE ONLY Boll VALUATION REPORT' RORM 2: 60lL l00 INFORMATION RROJ@CTT(Tt,E: SHEET: 2 OF 5 PROJECT N0. ;• DA7fi Pf1EPARED 8Y : ' 901LLC?p ; ~ see SEE ATTACHED MAPPING LOCATION:. 1. , E$ OF TE8T8 2. 8CS 801E 8ERI6B: 3, lANO FORM: ~N E'BACKHOE SPANANAY 6RAYELLY LOAM OUTNASH PLAIN EX CAVATED SOIL ~. @POSfTION. 4. HYDROLOGIC SOIL GROUP; e. DEPTH TO SEASONAE HIaH WATER' MI DRY: ~ ~ A 144" ± OU MASH ?. URRENT WA76R 8. DEPTH TO IMPERVIOUS LAYER; 9. MISC: ' DH ' SITE IS CLEAR PASTURE 144"+ 144 + LAND .. TNO SMALL HOUSE AND A ' DARN TO 8E REMOYED..SLOPES00-5~ 10. POTENTIAL FOR: RR0810N RUNOFF PONOING NONE MINOR NONE ' 11. SOIL PROPII@ DEBCIVPTIQNt HO DEPTH TEXTURE SiCL BTit MOT IND R00 (X) PeP SL~2 A 00-15" BLACK LOAM 10~ N N 15" . A 15-40" SAND AND GRAVE O N N 40" B ~ 40-70" COARSE SANG AND GRAVEL 0 ~N N 60" B 70-144" SAND AND GRAV W/ COBBLES •0 N N N 12 81TE P~RCQlATiON RATE: 1" PER M I N U T E 13.'PINDINQBd~RECOMMENDATIONe; DONNSPOUT BLOCKS AT RESIDENCES STORM POND B10SWALE FOR ROAD RUNOFF ~~. F-A ~ _ ~~~ =rom:CES NW INC. 253 922 ' 1954 04/ 10/2001 08; 27 #OG7 P ,OU4 PIIi~AR>•R: PLL~ASE Rl~1D ALL STAFF USE ONLY INBTRUCTION9 FIRST soil EvAt,ugTION REPORT ' FORM 2: 801E LOd INFORMATION ' PROJECT TITLE: SHEET: 3 OF 5 PROJECT N0, ;~ DA'rG : PREPAID 9Y : ' 801LLOQ . SE'.N SEE ATTACHED MAPPING LOCATION: . 1. TYPES OF TE8T8 1. SC'S 801E 8ER168: 3. LAND FORM: ~NE'BACKHOE SPANAtitAY 6RAYELIY LOAM OUTNASH PLAIN EXCAVATED SOIL 4. OrpO9R70N. 4, HYDRO~Ot31c soll oRauP: s. 08PTH TO;iP.A80NAl HIDH WATER: HISTORY; OUTIIASH A 144" + 7, CURRENT WA76R 8. DEFTFi TO IMPERVIOUS LAYER: 6. MI8C: ' DEPTH: SITE IS CLEAR PASTURE 144 + 144"+ LAND .. TMO SMALL HOUSE AND A BARN TO BE REMOVED..SLOPES09-5~ 'f0. POTENTW. FOR: ER081QN RUNOFF PaNDIN4 NONE MINOR NONE ' 11. SOIL PROPILE DESCRI PTION: HORZ OEPTH TEXTURE 'ACE 9TR MOT IND R00 (X) F8P _ SLl3 A q0-15" BLACK LOAM A ~ „16-40'•~ LOAMY SAND AND GRAVEL B 40-70" COARSE SAND AND GRAVEL B. 70-144" SAND AND GRAV W/ COBBLES 10~ N N' 8" o N N 40" 0 N N 60" 0 •N N •. 40" 12 SITE PERCOlAT10N RATE: 1" PER M I N U T E 13.'PIHOINO88R!'COMMl~NDATIONO: DOWNSPOUT BLOCKS AT RESIDENCES STORM POND BIOSWALE FOR ROAD RUNOFF . ~~ ~, bid LJy~~:Z til:.iGl;~ ~j 'adh ~5'e=~~95~Tb '^I~ ~PdOH~ d:1~0~ [I~HH~I J u~a-a~ From:CES NW 1NC. 253 922'1954 04/10/2001 08:2 #OG7 P.004 PRi!•AR'RR.' PLQ/IbE RPAD AU. 8TAFF U9E ONLY INbTRUCTlONB FIRST 901E PVAWATION REPORT' ' RQRM 2: 801E LOO INFORMATION PROJeCT TITi.C: SHEET: 4 OF 5 ' r6 PROJECT No. ;~ OA PREPARED BY : ' 801LLOQ . see SEE ATTACNEO MAPPING LOCATION:. 1, TYPES OF TESTS 2 SCS 80118ERIE8: 3. LAND FORM; . ENE' BACKHOE SPANANA1f 6RAYELIY LOAM OUT1iASH PLAIN EXCAVATED SOIL 4. DEP08RIpN. 8. HYDROL041C 801E GROUP; e. DEPTH 70 3EA80NAL HIDH WATER: HISTORY: ~ A 144" + ouTrlasH • 7. CURRENT WAT'6R B. DEPT}I TO IMPERVIOUS U1YER; 8. MIBC; ' OE~' R A L E 144"+ 144"+ AND A HOUSE SMALL LAND .. 7il0 • BARN TO BE REMOYED..SLOPES00-5~ 94. PCTENTiAL POR; ~ RR0810N RUNOFF PONOINQ HONE MINOR NONE ' 11. SOIL PR OP1lR QEBCRI PTION: HORZ DEPTH TEXTURE lI,CL 8TR MOT INb ROO (X) F®P SL~4 A 00-08" BLACK LOAM 10~ N N 8" B OS-144,'' SAND ANO 6RAV 0 .'N N 60" '! 2 8RE P ERCOLA-71pN PAIL; 1" PER M I N U T E 13. PiNOINC38d.l1ECOMM!'NOAT'IONd: DONN9POUT BLOCKS AT REIDENCES STORM POND BIOSti+ALE FOR ROAD RUNOFF ~,, . , • F-4 ~c~d ~.Idgs:z Tnc,~ ~i •a~~ s~^~~~~~s~tib '~~hd ~hlCiHd " / 7i ~J~JJ Q~~H~~I~ w~~a~ From:CES NW INC. 253 922'1954 OA/11)I2001 08:27 #067 P.004 PIUPAIIER: PLG#E llG1D ALL BTAFP U9E ONLY IN>lTRUCTION>s FIRST ealL rvAtuAnoN aEPOaT FORM 27 8011 t00 INFORMATION PROJECT TITI,L: SPIFFY: OF 5 PRpJ>t±C1' NO, 5 DATE : PREPARED BY 801LLOQ ' ~ see SEE LOCJITION:. ATTACHED MAPPING 1, TYPOS OF TESTS 2. SCS SOIL $ERI>a8: 3. LANG FORM: ~NE'BACKHOE SPANAWAY 6RAYELLY LOAM OUTWASN PLAIN EXCAVATED SOIL 4. OLP081TION. 4. HYDROCOOIC SOIL flROUP: 8. DI?PTH TO 5PA80NAL HIGH WATER: MI9TORY; OUTWASN A • 144" + 7. CURRENT WA76R e, DEPTH TO IMPEAVIpUB LAYER; 9. MISC: ' pL~' SITE IS CLEAR PASTURE 144"+ . n 144 + LAND .. TWO SMALL NOUSE AND A BARN TO BE REMOVEO..SIOPESOD-5~ `10. POTENTIAL FOR: ERQ610N RUNOFF PONpINO . NONE MINOR NOHE 11, 801E PROFILE 068CIU pT10N: • HORZ DEPTH TEXTURE 9`CL $TR MOT IND ROO (X) PSP SLd~5 A 00-12" BLACK LOAM 10 N N 12" 'A 12-60" LOAMY SAND • ANO GRAVEL 0 N N 60" 'B 60-69" SAND AND GRAY 0 ~N N 60" D 69-144" SAND ANO GRAY ~ W/ COBBLES O N N 60" 12 BiTEP~RCOLATIONRATL: 1" PER MINUTE - 13.~PINOINC~93RliCOMMENDATIONb: p0}INSPOUT BLOCKS AT RESIDENCES STORM PON BIOSWALE FOR ROAD RUNOFF ~, ~ - a ,~} - l 9~d 1•1H~~:~ i~~~~ 5T 'a,j~ Bh~~'~9S~Zb '~~fJ ~flOHd l-J~~~Ot! (ICIHHJI~ w4a.~ ALI'I-~A DESIGN SERVICE R.O. BOX 792 / WAUNA,WA. 98395 ph. (253)853-1592 I`'.Ida` • f / ~~ ~ ~ ~ ~ {1` 1~. ~ ` ~~ ~~~ ~ I I 1 W! ire/ i ~ I ~ l~`; ~` Mi! ; 1 i ~Mt i i ~~~ 1 ~~ 1 1 j i 1' 1 ~ \~ ~~~~ ff p ~I '1 i ~• 1~ I ~* ~ 1 t ~^ 1 ~ L,_-_____ ~ ~ 1 I 1 7 -- t if --- - 1 j h 1 j I 1 1~1 /!! 1 ~ t 1 '""~ SL#2 ~ , pms i 1I.(lw~~i/ " i ~ i -r*is i51 ~~ 1 - - r~ ~ 11 ~ t, I r I . ; ,~ ~, - 1 1 1 1 1 1 1 1j1 I I 111 .. ~~.~,~ /.'i ' f ~~1 ~.: ~Ir Sri ~ 1~1 Ii ~ + i~i 1 i ^L• SL~3 ' 1 1 1 II 1 1 ^ I t 1 1 ~" 1 I~tf 1 1 r^>r t I I I 1 1 I I I 1 1~ ~~ ~ ~ * 111 1 111_.._-_.111.,._.._ 111---~-111___ -J1L-.._-..JI K>f >- I ~ ~ ~' ~ ullr 1 1 a!^ it t ~ 1 1 1 I SL#;; ~~ry ~a~ G`J~~ yIH~'.L ZCll=1~ F6l ~adH ~r~~''~~S~Sh ~'~I'I ~hIU!-Ir~ ` ~ ~ . H.~~i=~,~ ~.I~~yH~ I ~ woad APPENDIX B Basin Exhibits Developed Basin Map, 11 x 17" B-1 Thurston County Geodata Topography Map B-2 133kJ1S H1Zll '3 15th s = ~ ° ° ~ mm~ ~~ ~- a x83 42486 VM '3~1~ OL£9'L£9-£9Z NOIl'J(11~1SN~J a3A3WS38(1~ aue'I~ Q Q z; :sn~ 8 311f1S 3 '1S H1Zl 80£9 __ o /IS ~ JN/d.~73N/JN3 7/~l/~ +~ w F+ O w~ w w II ~ ~ v .~ dtlW NIStlS a3d0'13A3a 1ladNIWll3ad ld~d ~~IH NWtll(ld rn r U N Q Z W U 0 ~ U Z = Q O ~ ~ ~ t` ZO J Q CV h Q ~ ~ O II ¢3 ~ rn W W O N F U Q Z ~D ca~~O Q ~ fn O '.`~ d ~ S N W ~ d-~ C~CG ~ 6 Q ~ Q 6 ~ Q ~ tip. M c~D ~ ~ M {]] ~ tD ~ SV R r'7 '~ o BEY U - ~ ~, .z ~ w ~ N (0 O ~ L i~afo~d o D U U N O cn ~ ~ I avoa i~oNVn ---- - - i-- .~ _..-1.-,---~ a---- 1 -- -- -~ -_ _ ~ ~~~ ~ _ y ~ - - ~ ~ -3- - - - - -3- - - - ~ - - - - -- .. __ 1 - ,~ ~, _ _ - 1 ~ ~ 00'g~` 3SS,£S.ION 'TfH99° lGZ o ,06' .. ., ',909f \ , / r r .t,~lZt., `~ o M„8S,fS.IOS „8 , S.IOS M„SO,Z6.105 `~ .. \ M„SO,Zb.IOS 'L i' ~. GV . t.+,,,~,i1,7P.lli; 6, I 1 ~ I 4~. v ~ ~~ \ ro ~ ~ _ ~ ~ .-ry- ~_ l II r I I \ ~ I I I I . r ... I ,. ~ ...I am ~O\~ I ~ I ~I ~ \ ~^ hl N~ _ 3 ~ r I ,`mo o , I~ n o `""d .. I \A' ~~ 00 \ ` f~ of I IN ~ N ~ I ~ I. ....f. ~ rv c0 - aJ `m° . I ~ V ~ `. n Z -, I N ~ I M W ~ \ l \ ~ J ~~- `~ ~ II I I ~p ftl~ \ ~ : , ,. i \ \ ~ ~ 0 99 g ~ I ~ ~ I I I ~ - - h± SI~.Zb.ios. _~ h,. \ ,~ s . ' . . . s ~ - I ~ I ` ~~ ao . . ~ a ,,, I I I ^ ~ ~ y _ '~ o . ° o z a,96 bz t3~ ! I ~ ~ ~ o M I N ! „ `' /' ~ ° s ~.RiS..R \ S1hR..SO ~ ; w°. ~ rrn I , ~ ~ / ~o /~ o . ~-~ b: I x I _ °O I I L' "-Qp ZE_ - ~ `~ .J ~ / W .6t 8Zi ~ ~ p I I _ ~ `.LZlfit- - - i ' M O~,L,Z~I S_ ,~ I M„SO,Zb.l05 ~ h1„SO,it_.16;_- _ ~ .o i s p U J C`J ; ..:.. :; s \~ I ~ I i I \ ] dv \ \ / S g5,'..9 :bZ' .. \ I o I ~V "~ I ~ ~ ° ~ .U V 0 Chi.,SO.Zb.VOS . Zjy ~ ~ `~°o I N `i:i I o I ~ i~ I I I I - 3SO,Zh,l01t_ ..- N / / ( ~ I ~ ~ i ~ I ~~ / ! ! I I I I I i~ I ~ I ~ 1 ~/ ~ ~3 I I I - I c, / ~ / 1_~ _ I ~ o I (t'• tD ' ~i• f/ ll ~y I I tv i,., _.. ~/ ,g SS" . ~~ h ~ I ~ ~ i . , o ~ J ~ ~ ~ _~ I _ w ---- - __ __ ~ _. I N ^ M- ^rt I w I ~ I ' ~" Z ~ ,Zf'9B ,lZ'68 19 .00 I ~; I ~ ~ „~ 3.05,LZ.lON 3,OS, LZ.ION 3~OS,LZ.ION ~ :n I `P I o . I ~ - "' _ _ I N ;~ ~n a- ~ ~ __ ~ I __ Thurston GeoDATA Center/Interactive Map Page 1 of 1 Map Produced By: Thurston GEODATA Center's Internet Map Server Scale: Approx. lInch = 151 Feet 4/12/01 9:18:32 AM ~_-~ :~ v http://www.gcodata.org/scripts/esrimap.dll`?name=TGCMAP&Lett=1 1 15939.82635034&(3... 4/12/2001 APPENDIX C Storm Water Calculations (also see work Map> Storm Shed Computer Analysis Printouts (Infiltration Trench) C-1 Bioswale Calculations C-3 Preliminary Plat Plan C-4 Running P:\00133\dwg\RLP-Corrected.pgm on Thursday, May 24, 2001 Summary Report of all RLPooI Data Project Precips [2 yr] 2.20 in [7-day] 12.00 in [10 yr] 3.00 in [25 yr] 3.50 in [100 yr] 4.10 in [6mo] 1.58 in BASLIST2 [Developed] Using [TYPE1A] As [100 yr] [Develop7day] Using [PC7DAY] As [7-day] [Developed] Using [TYPE1A] As [6mo] LSTEND BasinlD Peak Q Peak T Peak Vol Area Method Raintype Event ------- (cfs) (hrs) (ac-ft) ac /Loss Developed 3.2306 8.17 1.4630 6.64 SBUH/SCS TYPEIA 100 yr Develop7day 2.2365 56.00 4.9537 6.64 SBUH/SCS PC7DAY 7-day Developed 0.4872 8.17 0.3040 6.64 SBUH/SCS TYPE1A 6mo Drainage Area: Developed (100 year 24-hour Storm Event) Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 0.0000 ac 0 0.00 hrs Impervious 6.6400 ac 86.08 0.38 hrs Total 6.6400 ac Supporting Data: Impervious CN Data: Impervious (Roofs, Roads, Dr iveways) 98.00 2.8700 ac Lawn 77.00 3.7700 ac Impervious TC Data: Flow type: Description: ~ Length: Slope: Coeff: Travel Time Sheet Lot Flow 132.00 ft 1.00% 0.1500 20.42 min Shallow Street Flow 370.00 ft 1.00% 27.0000 2.28 min Channel Pipe Flow 202.00 ft 0.50% 42.0000 1.13 min ~~ ' ~ Drainage Area: Develop7day (100 year 7-day Storm Event) Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 168.00 hrs Area Pervious 0.0000 ac Impervious 6.6400 ac Total 6.6400 ac Supporting Data: Impervious CN Data: 7-Day Adjusted CN Impervious TC Data: Flow type: Description: Sheet None Entered Sheet Lot Flow Shallow Street Flow Channel Pipe Flow Length: Slope: 300.00 ft 0.54% 140.00 ft 1.00% 370.00 ft 1.00% 202.00 ft 0.50% Drainage Area: Developed (6 month 24-hour Storm Hyd Method: SBUH Hyd Loss Method: Peak Factor: 484.00 SCS Abs: Storm Dur 24.00 hrs Area CN Pervious 0.0000 ac 0 Impervious 6.6400 ac 86.08 Total 6.6400 ac Supporting Data: Impervious CN Data: Impervious (Roofs, Roads, Driveways) Lawn 77.00 Impervious TC Data: Flow type: Description: Sheet Lot Flow Shallow Street Flow Channel Pipe Flow Node ID: Infiltration Pond TC 0.00 hrs 0.38 hrs 98.00 3.7700 ac Coeff: Travel Time 0.1500 49.18 min 0.1500 20.89 min 27.0000 2.28 min 42.0000 1.13 min Event) SCS CN Number 0.20 2.8700 ac Length: Slope: 132.00 ft 1.00% 370.00 ft 1.00% 202.00 ft 0.50% Coeff: Travel Time 0.1500 20.42 min 27.0000 2.28 min 42.0000 1.13 min Desc: pond Start EI: 100.0000 ft Max EI: 105.0000 ft Contrib Basin: Contrib Hyd: Length ss1 ss2 Width ss3 ss4 30.0000 ft 3.OOh:1 v 3.OOh:1 v 28.0000 ft 3.OOh:1 v 3.OOh:1 v Control Structure ID: Infiltration -In filtration cont rol structure Descrip: Infiltration Start EI Max EI Increment 100.0000 ft 105.0000 ft 0.10 Infil: 20.00 in/hr Multiplier: 1.00 RLPCOMPUTE [RLP] SUMMARY 100 yr MatchQ=PeakQ= 3.2306 cfs Peak Out Q: 1.5690 cfs -Peak Stg: 104.68 ft -Active Vol: 0.21 acft 7-day MatchQ=PeakQ= 2.2365 cfs Peak Out O: 1.6811 cfs -Peak Stg: 105.01 ft -Active Vol: 0.23 acft 6mo MatchQ=PeakQ= 0.4872 cfs Peak Out Q: 0.4151 cfs -Peak Stg: 100.15 ft -Active Vol: 131.76 cf CN TC 0 0.00 hrs 76.40 1.20 hrs 76.40 6.6400 ac (___ -` ~- Size Biofiltration Swale Flow 3.32 Flow 0.49 slope (s) 1.00% depth (y) 0.25 Mannings n 0.2 Sides (z) 3 Actual Length 150 cfs (100 year) cfs (6 month) (bottom slope for for biofiltration design) ft. (3 to 1 side slope preferred) ft. (desired length is 200 ft.) Required bottom width (b) calculation Q = (1.49 / n) x A x RZ"x~ (mannings equation) A = (b + zY)Y "b" is solved for using a computer spreadsheet function to obtain a trail and error solution of b = 6.28 feet, for a desired length of 200 feet. check Q = 0.487 cfs, OK same as given Velocity = 0.277 fps < 0.9 OK Residence Time = 12.0 mins. Find bottom width for 9 minutes & actual swale dimensions (same Q) Actual Length 150 ft. Velocity (for 9 minutes) 0.28 fps Area (with same Q) 1.75 sgft. Bottom width b (same depth) 6.27 ft. Use 6.5 ft check Q = 0.49 cfs, OK same as given 100 Year Stability Check COMMON SECTIONS FOR DITCHES Flows based on mannings equation Flow Sides mannings SLOPE Width at water surfa Sec. Hydrauli Velocity flow O Depth slope n ft/ft Top Bottom Area Radius fps cfs 0.74 3:1 0.2 0.01 10.93 6.50 6.435 0.58 0.52 3.32 ~- Fi(cnunrr DOE/3/l)S{i';1 LF...4"l.S Tidy !3/U,SN ;4LE DOE Si~ 4/_'1101 ~:4 ~ P11 >,.a :uolslnctl '~N rt• :t»,. ,y e 9 ., h .. L'S n., '. fiY A,~,PY '...~ ...~ ~ta~ a . 4 ~ 1 ~ L ! ~ S :` aaaarrsna z Y ~, p059~ .. ' ~ ?' '~aae 4 95 as ~laeoN * U a S' ~~ ~ Z .: w > Y~'Ox f c, $ n ~'~' u i $• { r ~ ~ a %+c y~ i * ~ z ~ r. 1 .ep,~. a fr r,u ~ r k .f s ~ ~ y ~ b ~ b.y3 v. ' tw .~ ~ i. r: -' . vyt. a l; i{~fyi 9# a~ ~.) 1 ~ j f ,S ~-.i r ` n., , 9t YB0 VM 'vW00~1 '1S Hllll 15tl3 1911 fiY9D VM 'ilU OLC9-1C91C9219NOHd Iltl1SN0~ 1l3A3W338H(1~ ~°",~ 41t1 BDC9 ' ' ` ''"~"'"~""'"~~•~~ ' ° s w ° c ~m~ h~~ o ul `°o r c h l m n i5 3 Y907-220 ((C92)) lm9 B i7V5 NOII~ ~NI , 2C91-220 (E92) / a!~ vHU~~bns v oxrb~~aioH.~ ~i~» ltlld /latlNlWll3ad °e a ._ Z ,~11~f X1111-~~~ ltlld '1lIH NWfll(1~1 ,,.,e~d ao~ ~a' ~"c ~° ~7~ 1. ~ ~~~ ~1 a _ a 1 y y~ m u _Ll ~ ~ ~ ~ ~ ~ z ~ ~w~$ ~ ~~ ~ ~;~ ~~ ~ a ~ ~; ~ ~ a _ m u W a ~ ~ ~ ~ ~ s ~ ° ~ r~ 4 ~~ ~ W a ~ `~ a `~ ° a a °c3 " p ~ ~ ~ ~ ~ h V °~~ ° zc3c ~~ ~~ ~r ~ ~ v ~ o ~- ~ i. ~` ; ~I ~ 1 ~ i ^ ' ~ ~ lll . ~ w ~ I F i 1. t. i ` ~S -- ~ i , _ Y ~a3 ieilr~nvd o ~1 ~' ~ ~ ~ ~ldiNDYIf a o- 3 m r ~ m 00 ~ ~~ X00 ° ~ $ ~ ~ ~o $ffg ~~ ¢ p ~ b 3 Z '~°~ ~ e7i ~, ~ LS aq ~ vy ~ '° ¢ 3 ~ Gv~~J... `~$ ~S~y €.R-~~~ ~~ ~& ~~ocz3bS~& O •0J,1 ~~a+"~a i U N C`gµF~y{ ~.'j~~y,~°,~q°n9, ~F~ ~t'S~~u ~~ln~Z 16~~~87d 4 ~ IIJ ~Gd vGi ~ ° °O~ GG~~~ $rnnYe mog 3`~d~Z'~i' ab{~g~,y~~ ~~~~~ ~~n~~~ Fr. ~ ~ G 3~~~ per, .v x' N~'_",~aN~"',uRio ,~_ ~. ~ ~~ o ~~ ~~~ ~~ ~~ ~~~~~~~~o~~~~ ~ e 4 ~ "' ~ Z a~w~~ti ~~.,N`~o ~iW~~2""'6"'7L~~a~"~~r? u ~ ~~a•~!yJ+~d u ~ a'S~~Wa z~ ~~ ~oz ~IPi ~SS~ wwdg ~1 w ~~$ ~~~3u3'd ~ a ~~~~~~ ~~~~~ ogR~S~~~~~~~~3i= ~~~~ ~ ~~~ c6i ~~~~~Y~ ~a~~~~~`~ ~ °a ~i~" z ~ ~s~a`vs W~' ~+ z z Y o.oo.iD OC '6~ ~~~~ ~~~~ ~ o°ou V ~ ~~~~ ~~i ~$~~~Ca~^_ G~ m xi"vi' 4 mg' ~ F $ >~~ o'~N~{ ~~'_~'-~ to ~~g~~o ~e~ww ~°ay1~8z4~z ~ .g y ~~" `~ N oc ~&a~a'Og~4 }5~8~1j WGl e~h~~~ ~~~~~ N~~~i > Yi~~~~`~y'z~G > ardir^~y ~~ J ~+ ~ 6 ~F~~'_a-'w~"G5~~~3~~~~~~$ ~+ .~~~~75 z~ ``~~-$`~'~ u ~`'~~~~ ~~x+!'sF~ '`~'~pFp,, ~ tr "~~Y{{..!``„" i li r ~' ;~~~ N m~°~~~k~y 8'~~&d+~3< ~ ~~~~€F~Qz ~~~~Y a~r'~d ~uo ~ ~ CS~~ N ~m~YS~ m '~< %7 b b d T Z ~ p g& 6g h' tl ~"' ° '~ _ mN ~.- - - e£~xi ' ' Y . . J 3 >= . ^ ~` (~ Z .~ J ' ~ .af~v . Z3o Z `r `~ ,~ooc M~ .~VIS- `. ~ . N ~ a~-~ 0 Z N O 1= LLI O ~ C o d Q .. ,~+. ~n~o» . . W ~I~ v! I i; Dt ~, A gI~ ________i:-..--r.- __ ~-==-~T_.__ 1~ ~~ g~ ~_-= `' u * ~~ !~ j0 111JIN ! Q ~ ~~. ~ __.._ . I ~ ~ ~ ~ ~ ~~ ;;~~~~ Q~ a 3 ~.~~~ ~~~ qa ~~$~ ~4 g ~n . i~ a~ /~ // + ~ ~ ~ s; ;;~ g ~ ~ 1 ~ ] ~~~ ~ ~ 3i 3 ~n~nva ~o ~0 ~ 4 0 ~ 3 i ..b i f5 ,VM .3U 1FMJIH ti . ` ..