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Home My WebLink About03286 - Technical Information Report - Drainage , t . V � � STORM DRAINAGE REPORT � PROPOSED LARRY'S MAPLEWOOD ESPRESSO 3404 MAPLE VALLEY HWY SE '/4 OF SE '/, , SECTION 16, T. 23 N, R 5 E. W:M. RENTON,WASHINGTON 98056 RENTON PRE-APP NO. 04-043 FOR: Mr. Ted Thomas Prepared by Touma Engineers 6632 S. 191ST PI, Suite E-102 �Z11R w• T Kent Wa. 98032 ,��,°F '�.c� PH. 425-251-0665 ��' , s Fax 425-251-0625 � � �'�� 9470 �� JOB NO. 882-001-051 �l sfrnvnL �� EXPQtES /6 22/05 3 ZS� TABLE OF CONTENTS Pages I. PROJECT OVERVIEW 1-3 II. CONDITIONS & REQUIREMENTS SUMMARY 4-5 III. OFF-S1TE ANALYSIS 6-8 1V. FLOW CONTROL & WATER QUALITY 9-20 V. CONVEYANCE SYSTEM ANALYSIS ANU UESIGN 21-23 VL SPECIAL REPORTS AND STUDIES 24 VII. BASIN AND OTHER COMMUNITY AREAS 25 VIII OTHER PERMITS 26 ; IX. EROSION/SEDIMENTATION CONTROL DESIGN 27 X. BOND QUANTITIES WORKSHEET 28 XI. MAINTENANCE & OPERATIONS �IANUAL 29 � � . � . . � I. PROJECT OVERVIEW This project involves a parce! of land of approximately 0.59 acres. The project is situated adjacent and north of the Maple Valley Highway east of the City of Renton. It is located within the southeast quarter of the southeast quarter of Section 16 Township 23 North, Range 5 East W. M. The proposal is to construct a permanent 672 square foot "Espresso Stand" with associated driveways and parking. The site had a service station established in the 1960's and removed in the last few years. Access to the proposed project will be via a public road and an existing driveway from Maplewood Ave SE. Access from Maple Valley Highway will be via a new 30' wide commercial driveway and curb cut. The existing driveway cuts along Maple Valley Road are to be removed and new curb gutter and 6' sidewalk reconstructed. The soils on the site are composed of Puyallup series (Py) alluvial outwash with gravels and fine sands per the King County Soil Survey. The Puyallup series is made up of moderately rapid drained soils. The site is flat for most of the area with an average slope of 1 to 2 percent sloping down the the northeast. A 1' to 2' high bank is located along the north side of the site adjacent to the back of sidewalk along SE 6`� Street. Grading will be limited to construction of private road driveways and parking areas with supportive cut and fill slopes. The quantity of grading for the improvements on this site is estimated to be 300 Cu. Yd. The site has existing gravel driveways remaining from when the service station was removed. There will be no land that will required to be dedicated to the City on this project. REVIEW OF RESOURCES 1. Vicinity Map 2. King County Soil Survey Mapping. 3. City of Renton Zoning and Subdivision Ordinances Pg. - 1 � sEE - , �F� 656 - - --- --- -- L6z�- - - -- , . E � � N- - �-- - s6niti. � ' .'. . �__ .< I��y =y �. .� �. 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CORE AND SPECIAL REQUIREMENTS CORE REQUIREMENT #1: DISCHARGE AT NATURAL LOCATION "1'he allowable outflow from the site will be discharged to its natural location at the northeast end of the property. CORE REQUIREMENTS #2: OFF-SITE ANALYSIS Refer to off-site analysis on subsequent pages. CORE REQUIREMENTS #3: RUNOFF CONTROL Calculations are provided on subsequent pages addressing peak runoff. Sizing for peak rate runoff control facility and its routing do not appear to be required. Water quality control does not appear to be required based on less than 5,000 square feet of new impervious surfacing subject to tra�ic. Initial calculations indicates there will be no detention facility required because there will be less than 0.5 CFS increase for the100 year peak. Please refer to attached calculations in section 4 of this report. CORE REQUIREMENTS #4: CONVEYANCE SYSTEM The conveyance system will be designed using the rational method. CORE REQUIREMENTS #5: EROSION/SEDIMENTATION CONTROL PLAN The Erosion/Sedimentation control facilities wil( consist of filter fabric fences to be placed along the northwest and north margins of the site. CORE REQUIREMENT#6. - Maintenance and operation Maintenance involves having on-site catch basins cleared from sediments when necessary. CORE REQUIREMENT #7. - Bonds and liability SPECIAL REQUIRENIENTS: THOSE APPLICABLE TO PROJECI' I 1. Critical Drainage Area - The drainage basin is not part of any critical drainage area. 2. Compliance with existing Master Drainage Plan — N/A 3. Conditions Requiring Master Drainage Plan— N/A 4. Adopted Basin or Community Plans — N/A, 5. Special Water Quality Controls—N/A. Pg. - 4 6. Coalescing Plate Oil-Water Separators— N/A 7. Closed Depression— N/A 8. Use of Lakes, Wetlands, or Depressions for Detention — N/A 9. Delineation of]00-year Flood Plain — N/A ]0. Flood Protection for Type 1 and 2 Steam— N/A 11. Geotechnical Analysis and Report— N/A 12. Soil Analysis and Report— N/A I 13. A Wetland Mitigation Report—N/A. Pg. - S I11. OFF-S1TE ANAYSIS A: UPSTREAM ANALYSIS This proposed project does not have of�=site runoffentering the site. The property has existing curb, gutter and sidewalk on the north, east and south sides. On the west is the Taco Time oflice building with existing landscaping, parking lot, and storm drainage. B: DOWNSTREAM ANALYSIS 'The project site has an existing grade that is situated 2' to 3' above the surrounding streets and existing storm drain catch basins. See the attached existing condition sketch in this section of the report. Catch basin 1 on the sketch drains southeasterly then southerly to the storm drain system installed with Maple Valley Highway, and to 18,F9-1. Catch basin 1 on the sketch is a type l CB that is about 7 feet deep with 12' pipe outlet. The pipes and sizes information was gathered from the City of Renton Technical Services Map and information. There are a series of 12", 15" and 18�' pipes that total about 1148' leading to the 18" concrete pipe outfall into the Cedar River as shown. ' I Catch basin 2 on the sketch drains to 18,F8-6, and is about 3' deep on the north side of the Maple Valley Highway. The surface drainage along the north side of the site drains to the curb and gutter on the south side of SE 6'�' Street and flows northwesterly as shallow gutter flow. We did not observe any areas that indicated flooding or any undue washing of soils. Pg. — 6 , - � S\ / s'�\ / :__ �_,_ �s'�FFr\ .� `� E� _ - `\ \ �+. • \ \ �� -. �'i • \\ \ \ \ .;�` '� � � � \ /�--� ---- � - • \ / IXm _... / � 9 \,�� }�_ �� - � � \\ � IYPEI . � � — � . �`.s�,r j � - : ,� ; `�� ` e � `�/ � .�� . :� �� \ �� . \� �� ` '`� , \ � � , \ ' ` � ' -4A�� i ro `� ` . � ``\,� �`\ .\ s `q , \` `, / �� 69Fr : , ;� �'�-- �'. � ' ��r / �b �4 / �\ � _��\ . � D , �� , .� �_ ��, �� - '� , ,,.f � ��y - --- � � � �., � _--- - --�Y� � O E-gn `\ i t*� � � EXISTING CONDITIONS `� � �a► ""'�� / �v� SITE AREA = 25,496 SF = 0.5911� . Q� IMPERVlOUS /' �P GRA VEL = 10,950 SF �� PERVIOUS GRASS dc BRUSH =14,546 SF \� ' `\. / 1�DW�( S? �E�� Ly�c �; 'r�� , - 7 1 10� 7- 18, 7-3 �i 8,F7-1 � i � E7-Z 1 ,E8-1 18,F Z (lb� 3-12 18,F8-1 18,E8-11 18,E8-10 18,E8-9 18,E8-2 18,E8-S 18,E8-4 ��, 18,G8- vo' I�" _� 73, C� 18,E8-3 'S" 18,F8-S 18,E8- �3�,,5,� �� 6,�� GQO 18,E8-7 �`�_,_., �a � � ��,� �c� h 18,F'8-3 /'� .'� , r ��'� � 18,E8-8 �`�s•' �,,, �� ✓�~~ Z,, � ' '' r�J �/ i��\ �p.�� ,� �y� 18,F8-6 �s•� �J % , 18,F8-4 � ��9 J 18.F8-7 ��i� �-:� �, 'ig„ � � � 12'I �� 18,F8-8 � 3�� . �'2�i ' 18,F9-1 � �1 rf' cf �Siyrviv 7PGH�►�c�L so�� 1V. FLOW CONTROL AND WATER QUALITY The PreApplication Review Comments Report PREAPP No. 04-043 dated April 21, 2004 states that this proposal should comply with the 1990 KCSWDM for drainage and temporary erosion control plans. The area of the site to be developed is 0.59 acres, including asphalt paving, driveways, building and landscaping. There is no new added right ofway or frontage improvements required alon� Maplewood Ave SE. A new commercial driveway is to be constructed along Maple Valley Highway. The new added asphalt paving for the site and the joint use driveway will total about 13,425 square feet to replace about 10,950 square feet of existing gravel driveways tl�at remained when the service station was removed. Pre-Developed Conditions Pervious E3rush, Grasses 14,546 SF 0.33 AC. Cn=86 Impervious Gravel Driveway ]0,950 SF 0,26 AC. Cn=98 TC = ? L� = 120', S� = 1.9%, n9= .011 (gravel) T� _ .42(.O 11 x 120')R/(2.0)5(.019)a = 4.3 min. Post-Developed ' Pervious ' Lawn & Landscaping 11,399 SF 0.26 AC. Cn=86 ! Impervious Bldg. Roof(42'xl6') 672 SF Asphalt Driveways 13,425 SF Total 14,097 SF 0.33 AC. Cn=98 TC = ? L� = 120', S, = 1.9%, ns = .011 (asphalt) T, _ .42(.O l 1 x 120')g/(2.0)�5(.019)�4 = 4.3 min. � Computer data to be entered into the HYD program: lE2YR .33,86,.26,98,4.3 1D2YR .26,86,.33,98,4.3 P2 = 2.0", P10 = 2.9", P100 = 3.9" Pg. - 9 The King County Hyd. Program was used to calculate tt�e hydrographs for this report. The hydrographs indicate that there is less than 0.50 cfs. increase (0.53 —0.50 = 0.03) for the 100-year peak flow between the Pre-developed and Post-developed conditions. See page 1.2.3-5 of the King County Surface Water Design Manual (KCSWDM), for negligible peak runoflf rate increase. No runoffcontrol is required. WATER QUALITY This project will generate less than 5000 square feet of new impervious surfacing subject to automobile traffic. See the areas calculated above. Predeveloped gravel driveway 10,950 SF Post developed New driveway surfacing 13,425 SF New additional surface subject to traffic 13,425 — 10,950 = 2475 square feet. Therefore no biofiltration or water quality features will be required. Pg. - 10 • c.�JIfYU.EXE t; '' ., .. , , ., .... . , ..,;. . y.R, . 1: � � . • • t - s_c_s_ Tvrr-�n -- 7 bf1Y DCSiCN STORFI ' - SIORH DAIA FILE YLC I I'Y S I Ul{t1 OI'r 1 UN= �p z t�;�'�� TORH OYT[ONS: �,�r;� . 1. -- S_C.S. TVPF.. lA � �`:`� �-s�:�, - 7-DAY D�SIGN SIORH `�'.<:<"' - 570RN DATA PILIi ��.� �., PFCIFY 5TOftH OPTION: 1 ,' _C.S_ TYFF-111 RAINFAI.I. DISTRIDU7ION _NTER: PREqCYEAR). DURf1i10NCH0UR>, PRECIPtINCNES) ,24.2 ��w��+�*+��+��+�+�-� S.C.S. IYFE-1A DISIRIBUIION �N1f�flf�fM1E'IiM�Elfirif/FKiflfi(if ?.—YEAR 24—HOUIi 5IORM �» Z.HO" TUTAI. 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TYPE--1R D7.SiRIDU1'ION MMMMMMNHMMMMNNIIrMNMw /RMMMMHNMM 100-YEFlR Z4-�NOUR SIORt1 �ww� :T.90" IUtAL PIZG�.IF� MM%MMMYVM ---------------------------------------------------------------------- , FNI'ER: fl<YEKU>, CN<YERU), A<IMPERU). CNCIMPF.RU>, rC F'OR BASIN NO. 1 _33,.R6. _7.G,4f1,.1_3 nnTn PRiNT-OIIT: , AREACACHGS) 1'ERUlOUS I1IYLRUIOUS tC(MINUIES> A GN A CN .6 .3 66.6 .3 9R.4i �_� PEfIK-Q<CFS> 7-PE(1K(HRS) UOL(CII-P?) _5F1 ?_G7 G4A?_ LNTER fd' 7[patl�ltilename [.ext7 FOR SIORAGf OP C011I'UiED IIYDROGRlII'll- E1H0YJ� PECIFY: C - CONIINIIF.. N - NF.4JST0}{h, P - 1'HINt . S - !;iOP F.NTF.R: A<PER�J), CN(PERU>, A<IIIPERU), CNUMPERU>. 7C POR B(1SIN NO_ 7. i _?_6,8G, -33,9R,�1_3 UAiA PR1NI-UUI= ARF:A<ACRi�S> FGItUIOUS IMPERUIOIIS TC<11INUiES> R (:N R t'N .6 .3 86.� .3 98.A 4.3 Pl�nx--�ccrs� T-I'Ef1K<IIR6) UOL<CII FT) .S? 7.67 G7419 LNILIZ Id: Jlpakl�lfilenameL.ext] POR SIORAGC VI' CUMI'UIED lIYDRUGRAi'il= iD100YA . YECIFY: C - CQN7[NUE.. N - HE4JSTOHM, P - PRINT, S - STAP �� -- ►3 i � � . � � � / \ ' � � �. � � � � s�,� EQ-_.. �Fc�'�,� ,��` � \ �. . - - '\ \ \ . "� s,, • \ � �°' � - ' � ,� � � � � ---- �\ � a d �fA __ .,'' ., - � , _ ,,.ti, -- . .�, r` _^_`_ ,\ / �.a:,r � � - ,� �� ,, '�< � , � , � : •;� ��° . *�,,;,� �, ; ,; ;,�< ., .� '�lifA�� . / \ 'r� ' ..�,^� �\ `` .. `\� �� ',. \ 'R� `A� / ��` _ � � ` / y V -1 \\ '69�'r� ` ,,�,,. 4 ___ ', � , qr / , ' ,.� 3 �' .\ , ; � .�\ �, / .\ , , , \� ./- � ��- , �� \\ �y ------- � Q' �ev-ese� 2� „ „�R O r-sec.n �\ � . O '�". 2a EX/ST/NG CONOITIONS � �+► "'s'�� // �v� Sl7E AREA = 25,496 SF = 0.59bC� Q� IMPERVIOUS � ' �P GRA VEL = l0,950 SF �� / PERVJOUS GRASS dc BRUSH =14,546 SF \� ' `� / �� .� �j . — � �1 .� ' • . � � �/ s'c� / / 6�F� - �__. . Fr\ `,,� '� � .-.67.""'"" .. \\ \ � � � � �� .\ _ j�' _ � \� \ \ 'e; '� ---� �,. f- � �, j • � 6a � � �\ � �, . �.. -. '.� � �� , ��:,rj ) , - ( `�: � . � � � � .�,,,� � \� e :-� ,,, � -9'0�� <o� , , ' ; L - . �/ . `� . � C S� q�� . - / �\ �6,9Fj.� j ,� �\- . `� ,qr / 1� �•'� _ � / �\ � ��_/_ � \� �'�• 1 �� `\ $r � � � qrv-'°'ss�� DEVELOPED COND/TIONS �� O�P E-'.8J7 SlTE AREA = 25,496 SF = O.�C � �''�,�,f � �O lMPERVIOUS � .�.. �'" / l�, ASPHAL T = 13,425 SF Q�' ROOF = 672 SF `� � �P P£RV10US �� / LANOSCAPE =1J,399 SF �� \\, / l� . — �S , � � i . • - KING COUN '1' Y, WASlI1N (: TON, SURFACf: WA 'TER DESIGN MANUAI. -- _ _ . --------- - - -------------- ---- ------ --- -- - - --___— ----- - - _ _ -_ _._— '1'AQLE 3.5.2I3 SCS WFS'I'ERN WASlIINCTUN RUNOF CURVF NUMIIERS � --------- ---- -- ---- � SCS WESTERN WASHINGTON RUNOFF CURVE NUMBEFiS (Publlshed by SCS In i982) Runof(curve numbers for selected egrlcultural, suburban ancf urban land use for Ty��e 1A raltifall dlstrlbution, 24-hour storm duratlon. + CURVE NUMBEFiS BY NYDROLOGIC SO�-,GROUP ; LAND USE DESCRIPTION A B (C/ D u fCultivated land(1): winter condltlon 86 91 94 95 fMountaln open areas: low grbwing brush end gresslands 74 82 89 92 � Meadow or pasture: 65 78 85 89 � Wood or(orest larxl: undislurbed 42 64 76 8I ' Wood or(orest land: young second growth or brush 55 72 81 fl6 i Orchard: wfth cover crop 91 88 92 94 � OpRn spaces, lawns, pa�ks, goll courses, cemeterles, � landscaping. I good conditlon: grass cover on 7596 �-. or more oF the erea 6f3 80 86 90 � feir condtlion: grass cover on 5096 � to 75% of Ihe area 77 85 90 92 ; Gravel roads and parking lots � 76 85 A9 91 i Dlrt roads and parktng lots 72 82 87 89 ' , ` Impervlous surlaces, pavement, roofs, elC. 98 9[� �98, 98 ' j Open water bodies: lakes, wetlands, ponds, etc. 100 10U �0 100 � Single Famity ResidenNal (2) T — Dwelling Unit/Gross Acre 96 Impervious (3) 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 for pervlous a�d 2.5 DU/GA 30 Impervious portion 3.0 DU/GA 34 0l the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 OU/GA 46 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 7.0 DU/GA 56 Planned unit developments, 96 Impervlous condominiums, apartmenls, must be compuled commerclal busfness and Industrlal areas. (1) For a more detalled description ot agricultural land use curve numbers refer to National Engirieeririy Handbook, Sectlon 4, Hydrdogy. Chapter 9, August 1972. (2) Assumes roof and driveway runoti Is directed into street/storm syslern. (3) The remalning pervious areas (lawn) are consldered to be in good condition tor these curve nun�l�ers �' �a . -" ��v Z/R'� J � � � , KING COUNTY, WASHINGTON, S URFACE .W ATER DESICN M ANUAL FIGURE 3.S.1C 2-YEAR 24-IiOUR ISOPLUVIALS y,�- - -` � �-' � -� �,, ►- `p ��_:r - - --- - - - --.� -- --- 1 ..�• - - - M �� • -• L ;, .`�,,r.- I.� � Y � � � � ) � � - ti �� 5 � �_ t � r.� ��_ _ - :,,-. � ._F; .` �,, r.�► �� '_ _ . _ ..<< ��l ., �{ r� �/ - - :i.�_ �i .:/, NrrW p Y '�• . � _ � �=� � x� , - 'i '.�, r _ � ..�. �� ,� � rQ , a• n- �` _ -- -�, �., ;J N,. .r ' � /° ; �,,�a ; ! 2.Q �! 1 �r=�"` C' f - � ��, - � o� ,� � �� , _ �� i � ` l ��- ------ ... i' � ' , -< �E `� = u� � �� .i�`• � �� _ �� '�� ,. � � - �y �, �:s r� r��' }. _ i:r r� �� tl`` �� `(��'.,� I� � ,_. , � .�t �}) � �, � I i � A � � � � � � � � _.r y�� . '�' '�� _ �_ � __ .��.-.a �- ��1 i�� ,_ fi �� 1;' � � :7 / � � . /// I tl � � � � .�I . _� 1 �� ' _ jj � •- . r _ c ` � 'Y: ��y�- ...' � :� � __ F� )� � �� ' - � _` �.;`3;�� . � �-�� _ � •r- - �I� I l,_ � � " � ` ` "�^"',, : ; _ . i� �� '�.'- � t�s i/ i y _ � =� I' -�` � :�`a �\ � i _�J( � -� - . �+�: 5 � �. ,�. �, '�' `I �' l- - ,/ � j � •�.T t � ,i4.� �� 1. �J.Ar I ' � � I\ - ), \� �- _f �"1�.� l . .� .� ,� %� � '-��- !i � , .� . . � ,, ,. /,. � ... � 1..�� ..�' _J _�• — `�.� s'` �;r� i: � ,/ �� ,. �� f '�%� ��r i ( �.� t.• ��C � ..� -� ,� , '...�...... .! � I .. �,�( � �-- � �, � .�T f -�' �� ,- �- f�� _ ,, �.� � 'Y '�{ , _ N�,i �� ',� i� . � ..Y'�� 2'`.' '. � - ' - � - �I -�- ",� ,� �" ��` _� � '�` �� .. N� t� � ,�� ; � � � :� .��:_ � _ _, �— � t-�z ''� � �� d ( i � _ �' `�� Z�,�.r�� . _, � - f'�� - _.. N � � ,`� u.� r��. ''f/. .- _°l_. .� ---- '' �� i' ij� ... Z. D "�- -� •?� �' _� ��. 1 ry � ct - � _.� ��. � .., 1 , 1 2—YEAR 24—HOUR PRECIPITATION � �; � .. ,.3.4�' ISOPLUVIALS OF 2-YEAR 24-HOUR �► �� y - - _ I J 3• TOTAL PRECIPITATION IN INCHES -` �'` -- - ��`�, ` Y - t,. 0 1 2 3 4 S 6 7 E Mll�s `�` .� ry N ry ��:-,�Y �_ ,1� ��- ��r -�..,�- ,: 1:300.000 , J�1 f � '�J � r� � �/� r- � • • � KING COUNTY, WASHINGTON, S URFACE W ATER UESIGN hi ANUAL — — � . I FIGURE 3.S.lE 10-YEAR 24-HOUR ISOPLUVIALS 2.Y `-- � � - - ��, �—� _�� -�_� -- - - ----- - - -;� _ - 22 ,, „�� '.. �. � - .. -� '� :, �> �� •- - 23 } ' � _ :t �'� �j`� � --- �� - ' � ��`'� �. �,►� �� '�f� � � 24 ' . _ - - 1 ��" - � .�:s� � 40� �5 ' ' � ,,: ..._ _ ; � � � �1 ��-� t ?s � i — �i iwur � ,4 - ,. �\ ,-� 2� � _ ��.� � ,_`� S �J, ? - • -. ,- - �, _ �-• �.� �� _ .f� ,�. � 8 ' ti r � �J � / �I . ' � _..J= • fr �. � � � 2g �� i -� ' � ��- (C - � �1��, -"```' � � _. ,. . ; � �r - �,� `� J 3.0 - ' � ' ;_' - --- �.- `� ` � _±�i �1. _ � '� , � r�� S, � j " - TiIE f _�lj.'. _ �� F`` � G. •r .,�� /^ e • �� T r 1, ,.� ' 3 y ;�� :_ , � � �� '��. � ��. �� ' �` � � _ , - : -' - r,�,-�,. .r. ,< '�. i y�. . O 1 � ' � . aR .... � �' '�� - !lJ r 1 � �' 1 �. � � � ;I a?� � s ` `rs r:� ; !�. .j� � � / ,.. I ' - 1� �I �� .l t.��d1 .� - Iff+1�n i • � ,✓ 'II 33 � - _. ;� �.=� r _ - • r - • '� .�LL � ,i �� '". �' i _ r- � � ; , ti/ � . i [F Y .+y - �I �T -� ,[L ,Lr �� ...� e ;; � � 4. ` V� �„ — - l ! \--- �. ' ' �✓ 1\ i 1r/ r�Y_.i �� . CG�� . ,' �� _.._ •. ^ rr. �� ^ `� I� I � _ I ' ....�.._ . _ ,�� .+-�` __ � � .S'� . ' � _ .. � 1 l \_. �� _... �� \ ��"' � .�.. 1 � � ��. � �'- '' �-- �t�;'— �� — I � � - `' 1 i` � J'I� �` �� -- - J � ��Z L . —,�� ..�.... � / ' � -� _ �..�.:,, �i � � � , � * � l � ,� . � ,-�. � � � .._. e . ; ,� : � «.' � �"��- , `�--�,%� \ G'/' t `.l — � - . - ,, - _ '�� k .... `'i, ' _ „' l .'-,�_ � -F � - �' �: 4s,_ �4 ' � _ � �' ,., �, � i ' � ii �•'r� � -- -- � '.._ ��-- I�`.�� ' f ~ W�1 r --� � � �. � - ��• �; � � �� !_ � ,,.�f _ � �__ �' ',. �� b ' ,�i��t _ , ` .� �t -=z�"'' �; . _�� 'i��/ 1.. �` , � A �� J .�I ^ ,,- '_� s '1"`.:. j - :,�..i :1 ,,� .� — =' - ��- 4 — =� . "`'` � "`�.. � � � �� Y�� D��i :� �" = �._. ,^� / r•, u� � �/ . '�• . � �` -` - ;n`� .. �i_ ° I " � ` Y` _ � � _ �� - - - - 1 2 R�, � ' — - , c�� , ,c', � � , � � � 1 ; 10-YEAR 24-HOUR PRECIPITATION � ��; � � =u � � .o�. � 3.4�"' ISOPLUVIALS OF 10-YEAR 24-HOUR �'� . i ' � "' ` ��d� TOTAL PRECIPITATION IN INCHES nyQ ,` �"_ _ - � ,'' / ^�' - V ' '; — � � � , �-. 0 1 2 3 4 5 6 7 8 Mlles � �•,.� � _ .c• ,�^� a , w�; �-�:: , -- — �. — � c� 3.s.�-�o 3�g 1-_F< ,��'� 4.0 1: 300,000 � . • � � K1NC COUNTY, WAS HINGTON, S URFACE WAT.ER DESIGN M ANUAL FIGURE 3.S.lfl 100-YEAR 24-IiOUR ISOPLUVIALS -r_ - - -- - - --�r - - - - _ .Q - - - - �: i;; -wo' - Sa�eit - �' — -- — -. �, 3r` , _ N �. � _ ; ...' �3 - � -� � , "`�.. � � �.� , _� e.,. .4 ,' �- �__ ,, ; � _ � ` 36 ; � 3R 31 3 _ 1 _� y� - ,.� 7j�.- -,f/ RIA / _. " l {� � 4� , .ti" - =�" ~o - � ,� J( � ` � 4�'` ", �- ��' _ � ( --F� � � � ,�`' � � �- 4 � .. � �� , ,(� ---_-- .� '"��(J - '�� 3 ; _ ��',; M�, L — ._� � ; o 44 � �„ - E W __ �L�V ; '�: . ,.- (,-- `,' �. I �� J ' ;�� j - ` � Z - � • � ° �- C" S ` , ti. J ' I�1' t;��_1 - I, -- y J 4s '��, ,� � 1 ! ' ' �, � - '; A � w�) ;(� .� � _ � % . - � � .:��'/ � 5 J:_. —: _ l,, � - I 46 i _.:( _ �, '11� �— �..� � � � , "' `� �� _ . - T�..�.. � .� / .� �s...^ '�._ �. � •� _ _ ;� l , i :-� � I \ ��i' � /� - L;a � '� ` �� ' �e' r� � `� �' ' . - � ^ � ` I � �1� � _� T i.... 1 � 'CY ,�_ _� � • � _ `I—'! 1� ' I � ' � 1 -'� �� s' � � � i � 'a � I ,�, �' f `l '-�'-'- �,��- - ,� � i i ti , — _ ;', � �-t _ � c"�- i ` - � j �� - - � \ l t _ �� ..��_ _ � �3 �"r� - - ' - ��L �, i t' � � , � -� �� 1- " . �� (' � � � a � � ,.'� ,� _ _, � u_ {� � � �� 1 s� /� �/.��d�rj' yl� f \� `�� • � . �r - \ r, j- �� 1 - �! . _��,� � � � ��---� _ �� . � �1 � --f � ;��i � �� .� �� /' _ ;�� - `„� c�-r r - ;. "� � �� ;, ��;� _ _ �° r .. . 1� � � ';j _ ,w: l o,� ��' ? t— -,� �� _, -�� . �� f� - y� -� - .r� . .ti i, � �� , �i� r � r ,; _ � - ; - ��.� �� ` ;� -p , � �� -' .- -- - - - - _ ;. � �: � _ ' 3.q o �� - J �.�iG. �� - - - ��t_ ; � 100-YEAR 24-HOUR PRECIPITATION T, ,- � � 6.5 ...._._ �`p,'� - E � �� .;= ''` 5 C �3.4 ISOPLUVIALS OF 100-YEAR 24HOUR �� ,_Y �_ .5 I TOTAL PRECIPITATION IN INCHES '� Y ' % - :y . o�`� a;� �.o -- � .J-� z � ;, 0 1 2 3 4 5 6 7 8 Mlles (, '� , Jr �:'. i 3.5.1-13 f�< `_��Q`� O ."'� �"-;� _d' � 1:300,000 �� aJ'+� �� ✓ I . Tabte 1 C��nversi�n of SCS Soil Types to 'I'ill, Oulwash, and Wetland Classificati��ns SCS 5oi1 Type SC5 Modified Notes , Hydrnlogic SBUH Soil Group Group I Alderwood (AgB, AgC, AgD) C Till I Arents, Alterwood Material (AmB, AmC) C Till I Arents, Everett Material (An) B Outwash I E3eausi�e (BeC, BeD, BeF) C Till 2 Bellingham (Bh) I) Till 3 Briscot(Br) D Till 3 Buckley (E3u) U Till 4 I:arlmont (Ea) ll Till 3 I Edgewick (Ed) C 'I'ill� 3 �' Gverett (EvB, EvC, EvD, EwC) A/B Outwash t ' Indianola (InC, 1nA, InD) A Outwasl� 1 Kilsap (Kp[3, KpC. KpD) �' �'ill Klaus (KsC) (' Outwash 1 Neilton (NeC) n Outwash I Ncwherg (I�(g) B Till 3 Nc�oksack (Nk} C 1'ill 3 �, Norma(No) D 'fill 3 ' Orcas (Or) D Wetland � Oridia (Os) D "I'ill 3 Ovall (OvC, OvD, OvF) C Till 2 Pilchuck (Pc) C 'I'ill 3 Puget (Pu) U 'iill 3 Puyallu� (P ) t3 Til) 3 Ragnar(RaC, RaD, RaC, RaE) 3 utwas i 12enton (Re) D Till 3 S�lal (Sa) C Till 3 Sannnamish (Sh) D '1'ill 3 Sea�tle (Sk) D WeNand Shalcar (Sm) U Till 3 � Si (S►i) C Till 3 Snohomish (So, Sr) D Till 3 Sultan (Su) C Till 3 'i'ukwila ("�'u) D 'I'ill 3 � Wvodinville (Wo) D 'I'ill � I. Where ��utwash soils are saturated or underlain at shallow depth (<5 ft) h}� Klacial till, thcy shoul�l he treated as till soils. 2. These are bedrock soils, but calibration of HSPF by King Coun[y SWM shc�ws bedrock soils to have siinilar hydrologic response to till soils. 3. These are allwial soils, some of which are underlain by glacial till or which have a seasonally high water table. In the absence of detailed study, these soils §hould be treated as till soils. 4. Buckley soils are Formed on the low permeability Osceola mudflow. Hydrologic response is assumed to be similar to that for lill soils. ��, --z v V. CONVEYANCE CALCULATION The calculated 100 year peak flow from this site is 0.53 cfs. This flow rate will be 3.58 " deep. See the hydrograph calculation in section IV of this report. On the following pages of this report section is a pipe flow calculation indicating that a 12" pipe at 5=0.50% will carry 2.93 CFS when flowing at 93% full, maximum capacity. I � � P . —21 I � . • - tmp#l.txt Manning Pipe Calculator CHGGk. 1Z�� ►�►Pr= f�-T" Given Input Data: S� Q. 5 �� Shape . . . . . . . . . . . . . . . . . . . . . . . . Circular solving for . . . . . . . . . . . . . . . . . . . . . Depth of Flow Diameter . . . . . . . . . . . . . . . . . . . . . . . . 12.0000 in Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 0. 5300 cfs 4 � �OD slope . . . . . . . . . . . . . . . . . . . . . . . . 0.0050 ft/ft Manning's n . . . . . . . . . . . . . . . . . . . . . 0.0120 computed rtesults: �� pW VE-�j�� r Q„v Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5844 in Area . . . . . . . . . . . . . . . . . . . . . . . . . . 0.7854 ft2 wetted Area . . . . . . . . . . . . . . . . . . . . . 0.1970 ft2 wetted Perimeter . . . . . . . . . . . . . . . . 13.8774 in Perimeter . . . . . . . . . . . . . . . . . . . . . . . 37.6991 in velocity . . . . . . . . . . . . . . . . . . . . . z.6906 fps Hydraulic Radius . . . . . . . . . . . . . . . . 2.0440 in Percent Full . . . . . . . . . . . . . . . . . . . . 29.8703 % Full flow Flowrate . . . . . . . . . . . . . . 2.7292 cfs Full flow velocity . . . . . . . . . . . . . . 3.4750 fps critical Information critical depth . . . . . . . . . . . . . . . . . . 3.6259 in critical slope . . . . . . . . . . . . . . . . . 0.0048 ft/ft � Critical velocity . . . . . . . . . . . . . . . 2.6480 fps j Critical area . . . . . . . . . . . . . . . . . . . 0.2002 ft2 critical perimeter . . . . . . . . . . . . . 13.9679 in Critical hydraulic radius . . . . . . . 2.0634 in critical top width . . . . . . . . . . . . . . 11.0207 in specific energy . . . . . . . . . . . . . . . . . 0.4112 ft Minimum energy . . . . . . . . . . . . . . . . . . 0.4532 ft Froude number . . . . . . . . . . . . . . . . . . . 1.0226 Flow condition . . . . . . . . . . . . . . . . . . supercritical � I Page z Z tmp#l.txt Manni ng Pi pe Cal cul ato r C H E C K Wt �4 X G� Pl� G 1 T� �/ Given Input Data: v f= �Z '� }� / �i� shape . . . . . . . . . . . . . . . . . . . . . . . . Circular solving for . . . . . . . . . . . . . . . . . . . . . Flowrate Diameter . . . . . . . . . . . . . . . . . . . . . . . . 12.0000 in Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2000 in slope . . . . . . . . . . . . . . . . . . . . . . . . 0.0050 ft/ft Manning s n . . . . . . . . . . . . . . . . . . . . . 0.0120 Computed Results: M�¢�l Gpp,�-crTy Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 2.9353 cfs Area . . . . . . . . . . . . . . . . . . . . . . . . . . 0.7854 ft2 wetted Area . . . . . . . . . . . . . . . . . . . . . 0.7629 ft2 wetted Perimeter . . . . . . . . . . . . . . . . 31.4313 in Perimeter . . . . . . . . . . . . . . . . . . . . . . . 37.6991 in velocity . . . . . . . . . . . . . . . . . . . . . 3.8476 fps Hydraulic Radius . . . . . . . . . . . . . . . . 3.4952 in Percent Full . . . . . . . . . . . . . . . . . . . . 93. 3333 % `j3 % Full flow Flowrate . . . . . . . . . . . . . . 2.7292 cfs Full flow velocity . . . . . . . . . . . . . . 3.4750 fps Critical Information Critical depth . . . . . . . . . . . . . . . . . . 10.0112 in critical slope . . . . . . . . . . . . . . . . . 0.0068 ft/ft Critical velocity . . . . . . . . . . . . . . . 4.8363 fps Critical area . . . . . . . . . . . . . . . . . . . 0.7270 ft2 Critical Perimeter . . . . . . . . . . . . . 26.8720 in critical hydraulic radius . . . . . . . 3.8956 in Critical top width . . . . . . . . . . . . . . 12.0000 in Specific energy . . . . . . . . . . . . . . . . . 1.2149 ft Minimum energy . . . . . . . . . . . . . . . . . . 1.2514 ft Froude number . . . . . . . . . . . . . . . . . . . 0.8256 Flow condition . . . . . . . . . . . . . . . . . . subcritical � r II � Page Z � VL SPECIAL REPORTS AND STUDIES N/A, I Pg. -24 . . VII. BASIN AND OTHER COMMUNI'TY AREAS N/A Pg. -25 � VIII. OTHER PERMITS Commercial Buiiding Permits � I � Pg. — 26 � IX. EROSION/SEDIMENTATION CONTROL DESIGN The temporary erosion plan will be designed to reduce the chances that any construction related silty runoff will leave the site and affect downstream facilities. We will assume that the temporary sediment trap will be constructed toward the northwest corner of the site. This will be the lowest corner to install a temporary sediment trap that will be able to capture any runoff generated during grading, utility construction and building construction. From pages 5.4.5.1-1 of the 1990 KCSWDM a sediment trap for less than 3 acres development should contain a pond whose minimum surface area is calculated using the developed 2 year peak runoff. The trap should have at least a 3.5' depth to allow settling of the silt particles. The minimum surface area is to based on the formula; SA =FS (Q2/VS) where FS = Safety Factor= 2.0 Q2 = Peak 2-year developed flow= 0.22 cfs V2 = Particle settling velocity= 0.00096 f/s SA = (2) (0.22)1(0.00096) = 458.3 SF. Required 3:1 sicie slopes 0.0' - 2' x5' 1.0' - 8' xll' 2.0' - 14' x 17' 3.0' — 20' x 23' 460 SF at 3' deep 458 required OK 4.0' — 26' x 29' 754 SF at top of berm The sediment trap should be constructed at the lower portions of the site I Pg. —27 �I • . . � Ix. BONo QuArrTiT�s Pg. - 28 � , . . X. MAINTENANCE AND OPERATIONS Pg. - 29