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HomeMy WebLinkAbout02950 - Technical Information Report - Drainage . . . , STORM DRAINAGE REPORT FOR RIDGELIt' PLr1T RENTON, WnSIIWG"I'ON STORM nRAiNAGF, RF,PORT FILE NU. 9i7-015 (� - 2� 50 I'R}?1'.^Ri�.l) 1�1' TntJMA ENGINEERS b(i32. SOU"TII 191S'T PLACI:., Stil Cli 1�-IU� KLNT, WA. 9R0?2 (425)251-Of�S nct�hcr 24,2Of�1 V � � �� � �ca� �,, o � � y ���9I 4�77�� t `SIUI�TAL � E7�1Rk� 7/12/02 ���it cu:i.rnn��n nrcrr.� .i,.,• � . . . I. PItO.tECT OVERV[EVV The subject property involved in this plat covers an area of approximately 4.l3 acres. The property is situated in the north end of the City. The site is bounded on the west by Duvall Avenue NF (I 38th Avenue SE — King County Street designation) and on the south by NE 10`�' Street. It is bounded on the north and east by Hazen High School. There exists fairly large single parcels west and south of the site. Access to the property is made f'rom NE 10�" Street via a cul-de-sac tl�at would serve the proposed single lots. T}ie project area is hilly with average slope of 10%, except for small areas in the southeast and northwest portion of the property there exists slopes ranges from 24 -28%. Tl�e develop►nent falls within one small basin. The surface water is directed to the west toward Duvall Avenue NE and a wetland area situated in tl�e southwest portion of the property. The surface from the site is directed to open ditches on Duvall Avenue NE. The runoff from the site will be detained in open ponds type of retention facility and the outflow will be controlled and released to follow natural flow. The soil type of tlie site is Alderwood AgC, glacial till. Existing groundcover consists mainly of forest. Tl�e proposed plat will have 23 lots with lot sizes ranging from 4501 square feet to larger lot size of 9624 square feet. The plat improvements will be designed to City of Renton 5tandards and requirements for streets, storm, sewer, water and streetlights. 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' enr ti�r�: KING COUNTY AREA. �'ACHINCTTO?\T .i' . �� � .tr'--•- :. --•:-- �,- �° I � �E� � I I.�--- - .,-.:it:�' . >,�" IRENTQN c,i[�Ai)RAN(;LEi �.� �` :� . �. '' '��� _� ��I� �� ���. �'� .. -.- � ; � ,� ' __ 10' 1� - _______��1) • � , __II' — _ 1 680000 FEET 122°07'30" �R�c �. � ��J .... 47°30' i �� � . . . • p � , ' � �,�s , ,'N; �:��' ��d.:' -�E �• �• . . ��. .,ii y�:'v l � '�- . .. .... . "�� k' ��^~ ' II �^.I* :Iti��a��r�4i� ��:I• M...-i' �p'� I . . ♦��,`4`�r. II �+�..�w� � / . - �N t�4.w.'2� r U n . r�-, �. � i .�. Q4�ae t' .�. 1• • �� ,Z� • —_ i }G i �4+ A{�. �� �� ���<.• x . ` L� . 5��. • ,� � i � "� �: . .. �•�-ABC. :�y — -----_'' , ,•. I��►eC >• ' � ' ' �5 a.v : � ; 413• � ,� 1 p-� �BN •9i5 ';* L / n rw i j - � - :.�F, SoiG f YPE �7 C v ) � ° � :� " ,,•' - � '� .. • � �sa _ ;,, ` ' ,� � � i c� . - � � _ �.�:=_ : .�: -y, t�,....� �� - ��a�ewooa l�L . � 'v' �' • : ;.i�: L. � , ,� '•__ �... .:_�=• � �.:�' • • , ' II, , �• ► . 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I� �K' •I� � 0 . . �; h t: . �` " � �� n Yi R; 30,134 sq.ft. 0.69 ocres 600 sq.lt. 1.717 sq.fE. � 9�' ti� h r � �' �' � �� h � t�o�s 9Q.n. o.3s oc�es � o- �os sq.rr. `" �;29R yq.k. 0.19 ocres 1 sq.ft. 8,048 sq.ft. wetfand .€ t c c � -- s.�.� sq.n. � ��_ ( �C�/ q - - - - a��-�.u. - - - - � 0.02 ucrea � b �Q• : �.� �/"�� �G�/1_F_- Q �' � � Q' �f�iELOP.Cl7 $ � ��� �30,134 sq.It. h � � 0.69 ocres h h !t.l1CW IlI1 ' �JLC di7.IG i�ew w��N. 4,683 aq./t. exlst/ng 78 sq.ff. ex. l LOT SF access sum roof,dwy landscap. exist roof 1 7193 7193 2500 4693 5284 2 5817 5817 2500 3317 206 3 5284 5284 2500 2784 963 4 4754 4754 2500 2254 526 5 4503 4503 2500 2003 1717 6 4501 4501 2500 2001 600 7 4501 4501 2500 2001 S 4501 4501 2500 2001 9296 9 4501 4501 2500 2001 10 4511 4511 2500 2011 11 4634 4634 2500 2134 12 4984 1014 5998 3514 2484 13 4855 4855 2500 2355 14 4923 4923 2500 2423 15 4999 1035 6034 3535 2499 16 4587 4587 2500 2087 17 4502 4502 2500 2002 18 6675 6675 2500 4175 19 4973 4973 2500 2473 20 4973 4973 2500 2473 21 4970 4970 2500 2470 22 5427 5427 2500 2927 23 7181 7181 2500 4681 TOTALS 117749 2049 119798 59549 60249 ACRES 2.70 0.05 2.75 1.37 1.38 � 11. PRELIMINARY COND[TIONS SUMMARY I CORE REQUIREMENT #1: DISCHARGE AT NATURAL LOCATION The allowable outflow from tl�e site will be discharged to its natural location. The Level [ flow control is calculated to match the developed peak discharge rates to the existing site condition peak discharge rates for the 2-year and 10-year return periods. T}�e lowest elevation for the easterly basin is approximately 436.00. Refer to topography map prepared for the site. CORE REQUIREMENTS #2: OFF-SITE ANALYSIS Refer to off-site analysis on subsequent pages. COIZE REQUIREMENTS #3: FLOW CONTROL Preliminary calculations are provided on subsequent pages addressing runoffrate. The sizing for detention and runoffcontrol facility and its routing calculations are included in this report. COEZE REQUIREMENTS #4: CONVEYANCE SYSTEM The conveyance system will be designed using the rational method as presented in the King County 1998 SWM Manual. Refer to the"Analysis of Conveyance Pipes" calculation provided under this item. Based on the topography of the site we anticipate pipe slopes to be equal or greater than 1.0 %. The 100-year developed peak flow for the site was calculated at 3.12 cfs. The capacity of a 12-inch pipe with 1.0% slope is able to handle 3.87 cfs. King County Surface Water Design Manual 1998 requires to the conveyance pipes to be designed based on 25-year storm. CORE REQUIREMENT5 #5: EROSION/SEUIMENTATION CONTROL PLAN T�I�e Erosion/Sedimentation control facilities will consist of filter fabric fences to be placed along the northeast and northwest boundary of the site. Temporary Erosion and Sedimentation ponds will be considered for water quality control during construction of plat improvements. CORE REQU[REMENTS #6: MAINTENANCE AND OPERATION N/A CORG REQUIRCMENTS #7 FINANCl/�L GUARANTEES AND L1ABILITY N/A CORE REQUIREMENTS #8 WATER QUALITY �'he water quality facility proposed for this project consists of wet pond. Refer to calculation relate to sizing the pond. SWM SPECIAL REQUIREMENTS Special Requirements #1: Adopted Area Specific Requirements. �I'he site falls within the May Creek Drainage Basin. Special Requirements#2: Delineation of the 100-yr Flood Plain. N/A Special Requirements#3: Flood Protection Facilities. N/A Special Requirements #4: Source Control. N/A Special Requirements #5: Oil Control N/A �— - (ll OFF-S17'E ANALYSIS I. UPSTREAM � The site is the situated within a small drainage basin. The entire basin area is calculated at approximately 12.78 acres as outlined in the City of Renton Drainage Basin Boundary Map, dated 1996. Hazen High School has developed the upstream area and the runoff is intercepted by tlie school storm facilities. The runof�'is rerouted from tl�e entering the subject site. Therefore there is no of�site area to be considered. 2. DOWNSTREAM Surface runoff from the site is directed to the west either to open ditches along Duvall Avenue NE or wetland area situated oti the southwest portion of the site. Tlie flow is directed to existing storm system on NE 10`h Street on the south and Duvall Avenue NE oti the west. From the intersection of NE 10`" Street and Duvall Avenue NE the storm is conveyed west via underground storm pipe to Anacortes Court NE intersection with NE 10`�' Street. Thence the storrn is directed nortl� via underground storm pipes for a quarter of mile to another network of storm system on NE Sunset Blvd. Eventually, the flow cot�tinues west and north to Honey Creek in the vicinity of Union Avenue NE and NE Sunset Blvd northwest of the site. No downstream erosion has been noted. 1V FLOW CONTROL—WATER OUALITY TREATMENT DETENTION POND DESIGN The drainage basin runoff for this site will be detained by an open pond for one part and by a 24"diam storage pipe for the other part. The uphill basin that includes all roofs, sidewalks and on-site paving will drain to the detention pond. The off-site impervious areas of Duvall ave. plus landscaping runoff from several lots along Duvall ave. will be handled by the storage pipe that is located behind the sidewalk along Duvall ave. WETLAND RECHARGE: The restrictor catch basin the collects the pond outflow, will have two orifice risers. One orifice riser will transmit all flows upto the 2 year peak flow to the wetland, the second riser will transmit excess water flows and the 100 year peak flow directly to cb#10 and the down stream storm drain. items following: 1. Wetpond design 2. annual rainfa(1 figure 3. rainfall regions & scale factors figure 4. pond stage storage table 5. azeas to detention pond 6. KCRTS analysis for detention pond , 7. azeas to storage pipe ' 8. KCRTS analysis for storage pipe . . �ETPOND DESIGN WATER QUALITY : As the actual new pollutant generating impervious area along Duvall consists of only a 0.5' strip along the new curb,resulting in about 300 sf.,we reason that this area is not significant with regard to water quality treatment requirements. The water quality treatment for the on-site basin will be handled by means of a wet-pond section below the detention pond. The Wetpond volume for a basic wetpond is 3 times the volume of the mean annual runoff hydrograph. R : Total rainfall of the mean annual storm = 0.47"—See diagram on next page Atg : grassed till area= 56871 sf Ai : impervious area= 92089 sf Vr : mean annual storm volume Vb : wetpond volume Vr= ( 0.9*Ai + 0.25*Atg) * R/12 = 3828 cf Vb= 3*Vr= 11409 cf . 1 (i.4.1 WE"IFON[)S—RASIC AND LARGL—AfETNODS OFANAL}'S/S FIGURE 6.4.1.A PRECIPITATION FOR MEAN ANNUAL STORM [N INCHES(FEET) ST 1.0/ �p 1 2 ST 1.0 LA 0.8 LA. 0.9 LA 1 0 ST 1. 1 , ^"`" � "•* � - � q ...., .,.,. _�' � i ' � '�J '�- i I�"�' �� " I i;i :�l� � •�_. ._- - . i r 1.-��. �.. � F . . � ':''. � �y � �O ,. / � }�R at � �,:��:: � - � �'f_�, � . �_ .�:-.-.� l" �� ! b`�� � 1,� r �2 ., � �) n. 4.;e:v/'t ..� ' (_-. � � � � '!�� '�:.r� `�� ` + � �, ,r�'� .:L�- �� �1 - �FL ,l� � =� �" _� �:' - -� ,� � .��`.-�'- �,r.:�. A �`+ 4�' �' � �' �Jt f'r Y,. f �� � � _ � (''r 4. 1i • � �J ��f k IjY4i .! j rA4�. '!]'� !� . <_,..-- � � _ � / '� � � `, '�._. ! 1 nllett � ' 11r i t .; � �jcr. r� e .,��,�. t� .��� 1iT`r � '� �.-C� `�_I� r �� � ��. ,� '_ ��--�_�b £ �' � '� ,�� f; z �.�� i , � , � t � � .ti � r (,� ,4< < ����/�.�` _ , >� � � „1',�" 1 �\] L I � r i �'iL[4� ''�� ' r _Z �� ,,�.�-� ./ d� :. t . z�� f � i :°:: ! � �j' � f�i i . �,r� '.'..:i �t � '4-'i i� `�� .[� ��-t / �.. �\ � ,� � �. 4 � _ ; ti�� ! '_y s�. , -- . � ' ,�'---'�, � �.'' �i � ��f Rf 1 L �.� ' Y�rt,y — , �f �.1- �-" (- , ��� —. , _ ... `( �..�t � `{ '. ,,`��,� �.,i� �; o --...,(�I .. '� � 'H;; ; ii� .i V � � ,� , ��. � ' � �_ �, {. . . �. \ ,� r:k_r� � �,f J ( � `� /�/ .�. .. ? i ;, : �-„ tF=- ,1; � � i a j; - , .,, ! f � ;..... , � ��, Q ,.. , , O .. . z � � �- ;� '+_- �j -� � ;� -f; , .% _/ .� i Y • p � 0 � � `- r�1„'7 : � �''` � j i� � e � �'---.— - �� � ¢1'1.'�� �.c;- .� iI � �,,q.` �� � -� ��I�, tr'. � 1�41F �s i iead �t .C.G p - � . � —'—' _�_ .�.�":� �� `t'�iV��:}Y. �( � � �`��� ��_i.� �J I C�' '� j k�+ : �r.�i; � t -- ��. � �i �� �� � . �` �\� �i--"'_�� 9,-� -Y'�; 't" �•�` ��� ,~ 1I .���i � - / / �,�~c :r.=-� '�' ��~ � 0.54" •�� � .S,-��, - �0.045• ) � � a .��.;r- ', ` � o w:✓^�.t�s �-� J . .... �ee... � � 0.47" �� (0.039' ) � " �-. L__. ." r-=�'-`-k [f 1�� Incoryorated Area �: -`-=-' "� �t� RivedLake 0.47" �1 �i� — Major Road (0.03 9' ) p,52� — - �� � ` �� 0.65' NOTE:Areas east oi the eastemmost Isoplwial should use 0.65 �0.043'b.5 6" (0. 054' ) inches unless rainfaN dala is available for the location ot interest (0.04 7' ) ��The mean ennual storm is e conceptual stam famd by drvlding Ihe�nuei predpilation�y the totel rnimber o(sform eveMs per year result,generates large amounts of runoff. For this application, till soil types include Buckley and bedrock soils,and alluvial and outwash soils that have a seasvnally high water table or are underlain at a shallow depth(less than 5 feet)by glacial till. U.S. Soil Conservation Service(SCS)hydrologic soil groups that are classified as till soils include a few B, most C,and all D soils. See Chapter 3 for classification of specific SCS soil types. 1998 Surface Water Design Manual 9/1l98 6-69 • Sli('11ON 3.2 Rl_IrIOIT COMPUI'A"IION ANU I�NALYSIS h1E�i11C)US FIGURI;3.2.2.A RAINFALL RCGIUNS ANU REGIONAL SCALE FAC1'ORS ST 1.0/ + ST 1.0 LA 0.8 LA 0.9 LA 1.0 LA 1.2 ST 1.1 tMOMOYI�M pOVMt♦ .��R� ` en�Il eMwal � ■1Me eev � �A�, ., ,Jl,�_ a , ,. , . � ��� f - _.r 1' �-� r�� �� �\�,.��- ��, ..�.1�, _ \ c Y�s, d i�_l T _'_ —_-. ( �r ,•� � - �� �r ---�,- i"� ;., I � b � . , ' �•.7 t�E ONO.�� � . l � I. ��- � '`'� `y � ��...,� ' -1 � ,�� � _�7� � ;l ,y _J �� � -� r;� �� � j,;d . � , �.; .� : , �A � _ .� . ��� u '� +� . � � a F � f'.�n ..�.,�, j � J 4 r � j / eLIE E • '�t ;�' ��� �iS S �., ��� ' } '�1.. '�,'ir/� � ...` a '.�` ,\ � f •�f�ffll /t 1 . y'� � ' . �M f±` . . / I '� �-�'�t' • �I l 1 �i :' /' �..J �r ���. — ` ' re. � � � � '� �, i / , V - -�5.� ~ ..3 .� r 'l_� �. �` � s. ,� , �' �� � �i� d{i�,ed��ri.t ra�: ! C[�� - � �! �:, ,t ,�,� 4 r_.J.. . '�r ';:I �°. .� � ' i��6uMs. , F ' � _ . .?. - _' � Lf •!• 'f. (" . . _ '.t� ���y'��� \jp�l � �. .. ! — 7 -1 tt ^` � � .�� �� - EM�.4 - ..o, ._,( � •:r' ri?i ' , , , '�- �•. � '� • � 7q"� '� 1 t��`E .' � ��.f' /'i \l rr�usr � �� rs.s 'e T�C' � �� ' � j ' ;f ;� —�^ `�_ LANDSBURG � , ,;, � a �,� 'Y (� Ywlr� � �� K ' � " �w,. �5 i ' J v '. "f� ' 0 , .... ; �r,i` ,. i ' .�I . � �� kj#t ';�t, "6' `r '�/ '�LT,�'. 0 ,� d I� � 7•��'F4 (.I�,..} 1..1' y1`, F � � �_1• "_ }$ :. �y y . _ f�?J1 �ri,�M1 r �.' � ., � �� i��� i���8 � ta FI Y; � � ra ;� 1 t r c, .�• �..`�,__.y C�7yy P � ( i � ' r' ,'��;%` . 'V, . .�; . �: ��� �'-'`_\_ F. �' D,- � _� .tt " . w� y» ST 1.1 E;,�3,�� �)l i, `� -- �. _�...;F' ",�s � a, �.+�_ � a '�'�� 'jk�wo'eeowtr II[11C[COVN�♦ � ST 1.0 ,�. . � ��; :�.Z- � r-"""t.'ur- Rainfall Regions and LA 0 8, �' � � , \ Regional Scale Factors �A o.s�� �--�r-� C=--1 Incorporated Area LA 1.0 LA 1.2 �..c�� River/Lake Major Road 9/U98 1998 SurfAce Water Design Manual 3-22 POND VOLUMES, W 2:1 SLOPES �,' WALL IN WETPOND SECTION ELV STAGE AREA(sf) dV(cf) Sum V(cf) NEED (CF} 431.8 0 2152.0 0 0 433 1.2 2152.0 2582 2582 434 2.2 2152.0 2152 4734 wetpond 435 3.2 2152.0 2152 6886 wetpond ' 436 4.2 2152.0 2152 9038 ------- 437 5.2 2689.0 2421 11459 11409 ----------- 438 6.2 3257.0 2973 2973 439 7.2 3856.0 3557 6530 detention 440 8.2 4486.0 4171 10701 detention 441 9.2 5147.0 4817 15517 442 10.2 5838.0 5493 21�10 18576 POND DETENTION AREAS I', BASIN AREAS sf. acres sf. acres I total area 148960 3.42 ! DEVELOPED : EXISTING : on-site road &sidewalk 30134 0.69 pasture 138186 3.17 on-site roof+dwys(23) 59549 1.37 roofs 9296 0.21 off-site pavement 2406 0.06 off-site pavement 1478 0.03 - pond tract 6000 0.14 total impervious 10774 025 total impervious 98089 2.25 total area 148960 3.42 lots1-13,19-23 landscaping 47063 1.08 pond tract 2298 0.05 other landscaping 1071 0.02 off-site grass 439 0.01 total pervious 50871 1.17 739015areas.xfs i KCRTS Command CREATE a new Time Series ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series : 73915DV.tsf Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KCRTS\STTG60R.rnf . Till Grass 1.17 acres I Loading Time Series File:C:\KC_SWDM\KCRTS\STEI60R.rnf . � Impervious 2.25 acres ' -------------- � Total Area : 3.42 acres Peak Discharge: 1.31 CFS at 6:00 on Jan 9 in Year 8 ' Storing Time Series File:73915DV.tsf . , Time Series Computed KCRTS Command I CREATE a new Time Series ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series : 73915ex.tsf Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C: \KC_SWDM\KCRTS\STTP60R.rnf . Till Pasture 3.17 acres Loading Time Series File:C: \KC_SWDM\KCRTS\STEI60R.rnf . Impervious 0.25 acres -------------- Total Area : 3.42 acres Peak Discharge: 0.501 CFS at 6:00 on Jan 9 in Year 8 Storing Time Series File:73915ex.tsf . Time Series Computed EXISTING PEAKFLOWS Flow Frequency Analysis Time Series File:73915ex.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysie------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.265 3 2/09/Ol 15:00 0.501 1 100.00 0.990 0.137 7 1/05/02 16:00 0.267 2 25.00 0.960 0.267 2 2/28/03 3:00 0.265 3 10.00 0. 900 0.076 8 8/26/04 2:00 0.255 9 5.00 0.800 0. 153 6 1/05/05 8:00 0.292 5 3.00 0. 667 0.255 9 1/18/06 16:0a 0.153 6 2.00 0.500 0.242 5 11/24/06 4:00 0.137 7 1.30 0.231 0. 501 1 1/09/08 6:00 0.076 8 1.10 0.091 Computed Peaks 0.923 50.00 0.980 DETAINED POND OUTFLOWS: Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.405 2 2/09/O1 19:00 0.877 5.15 1 100.00 0.990 0. 119 7 1/06/02 6:00 0.405 5.05 2 25.00 0. 960 0.225 5 2/28/03 7:00 0.265 5.00 3 10.00 0. 900 0. 117 8 8/24/04 0:00 0.255 9.78 4 5.00 0.800 0. 154 6 1/05/05 11:00 0.225 4. 19 5 3.00 0.667 0.255 9 1/18/06 22:00 0.154 3.41 6 2.00 0.500 0.265 3 11/24/06 7:00 0.119 2.17 7 1.30 0.231 0.877 1 1/09/08 10:00 0.117 2. 11 8 1. 10 0.091 KCRTS Command CREATE a new Time Series ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series : 73915DV.tsf Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KCRTS\STTG60R.rnf . Till Grass 1.17 acres Loading Time Series File:C:\KC SWDM\KCRTS\STEI60R.rnf . Impervious 2.25 acres -------------- Total Area : 3.42 acres Peak Discharge: 1.31 CFS at 6:Q0 on Jan 9 in Year 8 Storing Time Series File:73915DV.tsf . Time Series Computed KCRTS Command Retum Penod 2 5 10 20 50 100 10� --___ _--- ----__ _ ---__.. -- - --- - • rdout.pks in Sea-Tac � ~�♦ RDOUT.pks I• 73915EX.pks -I • � � • R �— • • • ♦ --� • o0 � • '; � U � rn �p"�-1 - __ co - L U � � � -, �_. 10 2 I --- - ___ __ � ; .---- ------- 1 2 5 10 20 30 40 50 60 70 80 90 95 98 99 Cumulative Probability 73915PND2.DOC Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 2.00 H: 1V Pond Bottom Length: 120.12 ft Pond Bottom Width: 20.02 ft Pond Bottom Area: 2405. sq. ft Top Area at 1 ft. FB: 6344. sq. ft 0.146 acres Effective Storage Depth: 5.00 ft Stage 0 Elevation: 0.00 ft Storage Volume: 19698. cu. ft 0.452 ac-ft Riser Head: 5.00 ft Riser Diameter: 12.00 inches Number of orifices: 2 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1.72 0.180 2 3.35 1.56 0.085 9.0 Top Notch Weir: None Outflow Rating Curve: None Inflow/Outflow Analysis Peak Inflow Discharge: 1.31 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.877 CFS at 10:00 on Jan 9 in Year 8 Peak Reservoir Stage: 5.15 Ft Peak Reservoir Elev: 5.15 Ft Peak Reservoir Storage: 20566. Cu-Ft . 0.972 Ac-Ft Flow Frequency Analysis ! Time Series File:rdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.405 2 2/09/O1 19:00 0.877 5.15 1 100.00 0.990 � 0.119 7 1/06/02 6:00 0.905 5.05 2 25.00 0.960 0.225 5 2/28/03 7:00 0.265 5.00 3 10.00 0.900 0.117 8 8/24/09 0:00 0.255 4.78 4 5.00 0.800 0.159 6 1/05/05 11:00 0.225 4.19 5 3.00 0.667 0.255 4 1/18/06 22:00 0.159 3.41 6 2.00 0.500 0.265 3 11/24/06 7:00 0.119 2.17 7 1.30 0.231 0.877 1 1/09/08 10:00 0.117 2.11 8 1.10 0.091 Computed Peaks 0.719 5.13 50.00 0.980 73915PNn2.d�c Stage Elevation Storage Discharge Percolation Surf Area (ft) (ft) {cu. ft) (ac-ft) (cfs) (cfs) (sq. ft) 0.00 0.00 0. 0.000 0.000 0.00 2405. 0.02 0.02 48. 0.001 0.011 0.00 2416. 0.04 0.04 97. 0.002 0.015 0.00 2427. 0.05 0.05 121. 0.003 0.019 0.00 2433. 0.07 0.07 170. 0.004 0.022 0.00 2449. 0.09 0.09 219. 0.005 0.024 0.00 2455. 0. 11 0.11 266. 0.006 0.026 0.00 2467. 0.13 0.13 317. 0.007 0.029 0.00 2478. 0. 19 0.14 342. 0.008 0.031 0.00 2984. 0.29 0.24 593. 0.019 0.040 0.00 2540. 0.34 0.34 850. 0.020 0.047 0.00 2597. 0.99 0.44 1113. 0.026 0.054 0.00 2655. 0.54 0.54 1381. 0.032 0.059 0.00 2712. 0.64 0.64 1655. 0.038 0.065 0.00 2770. 0.74 0.79 1935. 0.094 0.069 0.00 2828. 0.84 0.84 2221. 0.a51 0.074 0.00 2887. 0.94 0.99 2513. 0.058 0.078 0.00 2946. 1.04 1.04 2810. 0.065 0.082 0.00 3005. 1.14 1.19 3119. 0.071 0.086 0.00 3065. 1.24 1.24 3423. 0.079 0.090 0.00 3125. 1.34 1.34 3739. 0.086 0.093 0.00 3185. 1.49 1.94 4060. 0.093 0.097 0.00 3295. 1. 59 1.54 4388. 0.101 0.100 0.00 3306. 1. 64 1.64 4721. 0.108 0.103 0.00 3367. 1.74 1.74 5061. 0.116 0.106 0.00 3429. 1.84 1.84 5407. 0.129 0.109 0.00 3490. 1.94 1.94 5759. 0. 132 0.112 0.00 3553. 2.04 2.04 6118. 0.140 0.115 0.00 3615. 2.14 2.14 6982. 0.149 0.118 0.00 367B. 2.24 2.24 6853. 0.157 0.121 0.00 3791. 2.34 2.34 7231. 0.166 0.123 0.00 3804, i 2.44 2.49 7614. 0.175 0.126 0.00 3868. I 2.54 2.59 8004. 0.189 0. 128 0.00 3932. ' 2. 64 2.69 8401. 0.193 0. 131 0.00 3996. 2.79 2.79 8803. 0.202 0. 133 0.00 4061. 2.84 2.84 9213. 0.211 0.136 0.00 4126. 2. 94 2.94 9629. 0.221 0.138 0.00 4191. 3.09 3.04 10051. 0.231 0.190 0.00 4257. 3. 19 3.14 10480. 0.241 0.143 0.00 4323. , 3.24 3.24 10916. 0.251 0.145 0.00 4389. � 3.34 3.34 11358. 0.261 0.147 0.00 4456. 3.35 3.35 11402. 0.262 0.147 0.00 4962. 3.37 3.37 11992. 0.269 0.148 0.00 4476. 3.38 3.38 11537. 0.265 0.150 0.00 9482. 3.90 3.40 11626. 0.267 0.153 0.00 9496. 3.42 3.42 11716. 0.269 0.157 0.00 9509. ' 3.43 3.43 11761. 0.270 0.162 0.00 9516. 3.95 3.45 11852. 0.272 0.167 0.00 9529. � 3.96 3.46 11897. 0.273 0.172 0.00 9536. i 3.4B 3.48 11988. 0.275 0.179 0.00 9549. ' 3.50 3.50 12079. 0.277 0.176 0.00 9563. 3.60 3.60 12539. 0.288 0.186 0.00 4630. 3.70 3.70 13005. 0.299 0.194 0.00 9696. 3.80 3.80 13479. 0.3�9 0.201 0.00 9766. 73915PNn2.d�c � .'�'I' G(1Nd5 16�.L 'ETIL 00'0 Oo9 'S 6bL '0 ' L6�:Z� 00'L OG ' �. 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'S � 'ZSLS OQ'0 G6T 'T 8L6'0 '6�80Z GZ'S OZ'S '089S 00'0 LLS'0 S9b'0 '�9ZOZ Ot'S OZ 'S '8095 00'0 S9Z'0 ZSb '0 '8696T 00'S 00'S '9�SS 00'0 Z9Z'0 6E6'0 'I6Int O6' 6 Ob 'b '6965 00'0 9SZ'0 LZb'0 'i6S8i 08' b 08'b '�6�:5 00'0 TSZ'0 bTb'0 'fsG08l OL' b OL'b ' �l�:S 1)0'(1 /.G!'i) l,f)b'(i '!l5/-1 Uy ' b 0`3 'b ' LSZS uu'u Z6l'U u6z 'U ' bts69l u�' �i US ' b ' LBI� UU'0 L�Z'0 8L� 'G 'Z969Z Gb' 6 06' b ' TTIS UO'G TE�'0 9yL' �U �LbbST OE' 6 0�'6 ' Z60S 00'G 9ZZ'0 bS�. 'u "GbrST OZ' 6 UZ' 6 ' ZL6� 00'0 OZZ'0 £6� '0 '6�6i�T OT ' b aT 'Y '�066 u0 '0 i�I�'0 :'�� '0 'S6bt�i �:�0'V 00' b � bf.8b UU 'il hUc. ' 0 (Jt:s 'C! oSc;tt �:i'r;� . ;li. �F KCRTS Command Size a Retention/Detention FACILITY ----------------------------------- Edit Facility Loading Time Series File:73915dv.tsf . , Time Series Found in � Memory:73915dv.tsf . � Time Series Found in Memory:73915dv.tsf . Edit Facility � Time Series Found in Memory:73915dv.tsf . Saving Retention/Detention Facility File:73915PND2.rdf . Starting Documentation File:C: \KC_SWDM\JOBS \73915PND2.doc . Time Series Found in Memory:73915dv.tsf . Edit Complete Retention/Detention Facility Design ----------------------------------- Edit Facility Time Series Found in ' Memory:73915dv.tsf . � Saving Retention/Detention Facility File:73915PND2.rdf . Starting Documentation File:C:\KC_SWDM\JOBS \73915PND2.doc . Time Series Found in Memory:73915dv.tsf . � Edit Complete Retention/Detention Facility Design ----------------------------------- Edit Facility Time Series Found in Memory:73915dv.tsf . Saving Retention/Detention Facility File:73915PND2.rdf . Starting Documentation File:C:\KC_SWDM\JOBS \73915PND2.doc . Time Series Found in Memory:73915dv.tsf . Edit Complete Retention/Detention Facility Design ----------------------------------- Saving Retention/Detention Facility File:73915PND2.rdf . Starting Documentation File:C: \KC_SWDM\JOBS \73915PND2.doc . Time Series Found in Memory:73915dv.tsf . II Retention/Detention Facility Design ----------------------------------- Route Time Series through Facility ---------------------------------- Time Series Found in Memory:73915dv.tsf . Reservoir Routing [R/D Facility] Inflow/Outflow Analysis Storing Time Series File:rdout.tsf . Facility Routing Complete Peaks Calculation. .R/D Facility Flow Frequency Analysis -------------------------------------------------------- Time Series File:rdout.tsf Project Location:Sea-Tac Frequencies & Peaks saved to File:rdout.pks . Peaks Calculated Peaks Plotting Reading Flow Frequency:rdout.pks . Reading Flow Frequency:RDOUT.pks . Reading Flow Frequency:73915EX.pks . I End Graphics Command ' DownStream Analysis Complete Retention/Detention Facility Design ----------------------------------- End Sizing Retention/Detention Facility KCRTS Command eXit KCRTS Program ------------------ STORAGE PIPE DETENTION AREAS BASIN AREAS sf. acres :ctai area 3�602 0.7- EXISTING : sf. acres DEVELOPED : new impervious 2952 0.07 casture 173�� J.�� off-site pavement 15744 0.36 off-site pavement 15744 0.36 :ctai ;mper�ficus ';869F 0.�::; ,otai mpe�iia�,� '1�-�4 J . , lots 14-181andscaping 13186 0.30 off-site landscaping 1720 0.04 ?ocai area 3:3�3Q� � -^ -ctal .^er��icUs �a9G6 ��7.�� KCRTS Command CREATE a new Time Series ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series : 73915PDV.tsf Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KCRTS\STTG60R.rnf . Till Grass 0.39 acres Loading Time Series File:C:\KC_SWDM\KCRTS\STEI60R.rnf . Impervious 0.43 acres -------------- Total Area : 0.77 acres Peak Discharge: 0.275 CFS at 6:00 on Jan 9 in Year 8 Storing Time Series File:73915PDV.tsf . Time Series Computed KCRTS Command CREATE a new Time Series ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series : 73915PEX.tsf Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KCRTS\STTP60R.rnf . Till Pasture 0.91 acres Loading Time Series File:C:\KC SWDM\KCRTS\STEI60R.rnf . Impervious 0.36 acres -------------- Total Area : 0.77 acres Peak Discharge: 0.220 CFS at 6:00 on Jan 9 in Year 8 Storing Time Series File:73915PEX.tsf . Time Series Computed � Retention/Detention Facility Design ----------------------------------- Route Time Series through Facility ---------------------------------- Time Series Found in Memory:73915pdv.tsf . Reservoir Routing [R/D FacilityJ Inflow/Outflow Analysis ----------------------- , Storing Time Series File:rdout.tsf . � Facility Routing Complete �,I Peaks Calculation. .R/D Facility Flow Frequency Analysis -------------------------------------------------------- Time Series File:rdout.tsf Project Location:Sea-Tac Frequencies & Peaks saved to File:rdout.pks . Peaks Calculated Peaks Plotting Reading Flow Frequency:rdout.pks . Reading Flow Frequency:73915PEX.pks . Reading Flow Erequency:73915PDV.PKS . Reading Flow Frequency:RDOUT.PKS . End Graphics Command DownStream Analysis Complete Retention/Detention Facility Design ----------------------------------- End Sizing Retention/Detention Facility KCRTS Command eXit KCRTS Program ------------------ . � Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 0.50 0. 0.000 0.000 0.00 0.02 0.52 0. 0.000 0.013 0.00 0.04 0.54 0. 0.000 0.018 0.00 0.06 0.56 0. 0.000 0.022 0.00 0.08 0.58 0. 0.000 0.025 0.00 0.10 0.60 0. 0.000 0.028 0.00 0.11 0.61 0. 0.000 0.031 0.00 0.13 0.63 0. 0.000 0.033 0.00 0. 15 0.65 0. 0.000 0.036 0.00 0.23 0.73 0. n_nnn n. �an n nn 73915pip.doc Retention/Detention Facility Type of Facility: Detention Tank Tank Diameter: 2.00 ft Tank Length: 130. ft Effective Storage Depth: 1.50 ft Stage 0 Elevation: 0.50 ft Storage Volume: 329. cu. ft Riser Head: 1.50 ft Riser Diameter: 12.00 inches Number of orifices: 1 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1.83 0.112 Top Notch Weir: Rectangular Length: 3.00 in Weir Height: 1.42 ft Outflow Rating Curve: None Inflow/Outflow Analysis Peak Inflow Discharge: 0.275 CES at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.289 CFS at 7:00 on Jan 9 in Year 8 Peak Reservoir Stage: 1.55 Ft Peak Reservoir Elev: 2.05 Ft Peak Reservoir Storage: 329. Cu-Ft . 0.008 Ac-Ft , Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0. 129 3 2/09/O1 3:00 0.289 1.55 1 100.00 0.990 0.078 8 1/05/02 17:00 0.131 1.50 2 25.00 0.960 0.128 9 2/27/03 8:00 0.129 1.50 3 10.00 0. 900 0.080 7 8/26/04 3:00 0.128 1.50 4 5.00 0.800 0.108 6 10/28/09 18:00 0.123 1.98 5 3.00 0. 667 0. 131 2 1/18/06 14:00 0.108 1.39 6 2.00 0.500 0. 123 5 11/29/06 4 :00 �.080 0.77 7 1.30 0.231 � , �nn �n� -� . nn n n�a n �� R 1 . 1 n �_t1Q1 Retum Penod , ` . ' 2 ; 5 10 20 50 1 QO � � 10� ;- ---- -------- -- ___ -- �. � rdout.pks in Sea-Tac ♦ 73915PEX.pks 73915PDV.PKS ��,• RDOUT.PKS �'I � i I ; • II � I � � � � � I R _ � • U � • � rn 1 p_1 i' � N —_-�----- � � • ♦ � � � � � � � , � , � � i i � 10 - -- —T—_ _ —r- ------- ----.__ 1 2 5 10 20 30 40 50 60 70 80 90 95 98 99 I Cumulafive Probability j J EXISTING PEAKFLOWS FOR SUB-BASIN TO 24"STORAGE PIPE Flow Frequency Analysis Time Series File:73915pex.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Erequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.109 5 2/09/O1 2:00 0.220 1 100.00 0.990 0.088 8 1/05/02 16:00 0.132 2 25.00 0.960 0.129 3 2/27/03 7:00 0.129 3 10.00 0.900 0.092 7 8/26/04 2:00 0.118 9 5.00 0.800 0. 109 6 10/28/04 16:00 0. 109 5 3.00 0.667 0. 118 4 1/18/06 16:00 0. 109 6 2.00 0.500 0. 132 2 10/26/06 0:00 0.092 7 1.30 0.231 0.220 1 1/09/06 6:00 0.088 8 1.10 0.091 Computed Peaks 0.190 50.00 0. 980 DETENTION STORAGE PIPE PEAK OUTFLOWS Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.129 3 2/09/O1 3:00 0.289 1.55 1 100.00 0.990 a.078 8 1/05/02 17:00 0.131 1.50 2 25.00 0.960 0.128 4 2/27/03 8:00 0.129 1.50 3 10.00 0.900 0.080 7 8/26/04 3:00 0.128 1.50 9 5.00 0.800 0.108 6 10/28/04 16:00 0.123 1.98 5 3.00 0.667 0.131 2 1/18I06 14:00 0.108 1.39 6 2.00 0.500 0.123 5 11/24/06 4:00 0.080 0.77 7 1.30 0.231 0.289 1 1/09/a6 7:00 0.078 0.73 8 1.10 0.091 Computed Peaks 0.236 1.53 50.00 0.980 DEVELOPED - UNDETAINED PEAK FLOWS INTO STORAGE PIPE Flow Frequency Analysis Time Series File:73915pdv.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.134 6 2/09/Ol 2:00 0.275 1 100.00 0.990 0. 107 8 1/05/02 16:00 0. 165 2 25.00 0.960 0. 162 3 2/27/03 7:00 0.162 3 10.00 0.900 0.113 7 8/26/04 2:00 0.142 4 5.00 0.800 0.137 5 10/28/04 16:00 0.137 5 3.00 0.667 0.142 4 1/18/06 16:00 0.139 6 2.00 0.500 0.165 2 10/26/06 0:00 0. 113 7 1.30 0.231 0.275 1 1/09/08 6:00 0.107 8 1.10 0.091 Computed Peaks 0.238 50.00 0.980 . ' !- Sheetl I ANALYSIS OF CONVEYANCE PIPES _ --_-- _ _ - _ -- � - �_ _ _ I--- -; - - ---- ---- _ -- - ----- THE ANALYSIS IS BASED ON MANNING EQUATION USING TWO TYPES OF PIPES. - _ ---- - - - -- -- - - - -- - -- - - - CPEP CAPACITY p 1.49/n'A'R"(2/3)'S"(1/2) _ __ __ _ --- -- - -- - -- -- FULL FLOW,SO THAT R=A/P=D/4 -- 1 _ _ - --- _ ___ . _ - - -- - _ ---- - - - - _ _ -- -- Showing minimum sbpes for 12"pipes - - --- - ------ --- --- -- - - - --- -- -- -- -- --- 100Y-devd - -- ------ ----- --- -- - - -- -- - - - ___- -- -___ n L(ft) S D(ft) R v(fps) A(s� Q{c/s) - - --— -- - -- -- - - ---- -- -------- -- - --- --- 0.012 4a 0.01 1.00 0.25 4.93 0.79 3.87 n-12 _ ---- --- ------ - -- - ------------- --- - - - --- YOU WILL NOTE THAT 12-INCH PIPE AT A MINIMUM SLOPE OF 1.0 PERCENT WILL CARRY MORE THAN ---- --- ---- --_ _ - __ _ THE 100-YEAR DEVELOPED PEAK FLOW OF 3.12 CFS(REFER TO FLOW FREQUENCY ANALYSIS-DEVI5.TSF). Page 1