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Home My WebLink About03259 - Technical Information Report - Drainage��,__�:: _ � 5�� -- 2� - 3z�G1 � L�V�.i., '? ANAC.,Y'�TS � '�'OR, m �A�;':��1�iAH .�T THE F�RK � ' 9�9 UN1C)1v A��NUE;2�IE ' ' REN`TC)N, �r�SH'II�iCrTQN ;.�j ' ��'�t�� FILE NO. 825-008-041 � PREPARED BY TOUMA ENGINEERS 6632 SOUTH 191 ST PLACE, SUITE E-102 KENT, WA. 98032 (425) 251-0665 ��.�� '`� � ��, � July 7, 2005 � �� Revised August 23, 2005 �`� �.��L � � L �� r�� {y� � � y ��L ,�.' �y- Z -+�, D,' � f�.,i � �:��. $si?( $'�'�,. ��C'1$-(i:.E�"'��.�p� � k�,�1 �:✓M .\ �F1 f i�i��i.J'�',�....._.._....._ --_ �_'_�.,��.� .-..�.as_.,. . . ...i �:..--'"�`�`fa71:�i�q�.,.i''r'.%:IT17-' P,.,..-. .__.,.:_..,��.. 7- _...___� � �3259 TABLE OF CONTENTS TABLE OF CONTENTS � Pages 1. PROJECT OVERVIEW 1-3 � IL CONDITIONS & REQUIREMENTS SUMMARY 4-5 III. OFF-SITE ANALYSIS 6-7 IV. FLOW CONTROL & WATER QUALITY 8-17 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN 18-19 VI. SPECIAL REPORTS AND STUDIES 20 VII. BAS1N AND OTHER COMMUNITY AREAS N/A 20 VIII OTHER PERMITS 20 IX. EROSION/SEDIMENTATION CONTROL DESIGN 21 X. BOND QUANTITIES WORKSHEET N/A STREET LIGHTING 22 � � I. PROJECT OVERVIEW The subject property involved in this plat covers an area of approximately 1.73 acres. %hei•e exis•!.�•.smul!uff=.��ite cu•ea co►rh�ihi�ti�ig ta the s•ite, crpproximately 0.2-1 acres, .sitt�atecl sur�[h►vc.�.��! � of�the .s�te. 7his rep��rt ►��ill acldress lhe basin area c f/.97 acres The property is situated in the north end of the City. It is bounded on the east by Union Avenue NE. lt is bounded to the south by Kiwanis Park, and to the north by Gustafson subdivision. It is bounded on the west by fairl_y large lot and the Seattle Transmission Line right of way. Access to the proposed subdivision will be from Union Avenue NE via a cul-de-sac that will serve the proposed 10 lots fi-om a single new intersection. Union Ave NE is developed at this time. The project area is fairly flat with average slope of 5-6. The development falls within one small basiil. Ttie surface water is directed to the east toward Union Avenue NE. "The storm will be directed to an existing underground storm system in Union. The surface water runoff from the site will be detained in retention facility and the outflow will be controlled and released tc� follow natural flow to the south. The ground cover consists of grass and several evergreen trees scattered over the entire property. 7he C'ity stcrff c�»tsideis�ortion of the westerly area to be a hnlf fores7 a�rd a hu1� gras.��. %he estimate cn��cr.falls within this coverage is calctrlatec�at 0./2 acre.r. 7he peak.�•.fluw.�� areu calctilcrted ijic/tating the fores[ed a�•eas. Several deciduous trees planted around the existing house. There exists a house, detach garage and associated landscaping. The house will � not remain and will be removed. The soil type of the site is Alderwood AmC, Arent, Alderwood glacial till in accordance with Soil Conservation Survey. The proposed plat will have 10 lots with lot sizes ranging from 4566 sf. to 1 1,585sf. "fhe ��lat improvements will be designed to City of Renton Standards and requirements for streets, storm, sewer, water and streetlights. See the figures on following pa�es: Vicinity map Soils 1��1ap Pg. - 1 � � � •• ��...-' � _ � M [ � �1 --�" 9I M � ~ �; �K fAQf 1 I t�� (� �` �� 1 L--}I[1 �� h „s—� 6) �t°° � I 5 sa _ 58 4 _ s�+X �0 1�_ •!, � 4i ` � -P �� . r i1 J_ m�;��I �•; " 4�E� 5�'o � _ '��e�` '� '� , � 13 ° a�. � . , 1► �, __ _ „on . �T_ � on � ..' � � , .,. • � - , -�-' t Ja W �� ' ' J*'� � x � � ''s �3 -D '� 'A �e�'a �" '�� 9�^ F- n� - OS Z� s�S 4�� M '°�• c� z � 1_ N�. i s � � ?� �D ( S sp��Z_ _iOL37 3 � � M 14 � " , I v+ '� � � . 1 � ��. � � � L1J ,��+ �' R1 17 16 IS o 33 32� � r 1�Y1 33J `''� _B � � _-�_—� l-�IO� �-� � �r � �^� g � �' N =� N .., �rI�.., 6� � _ `�� 0�6� �p Sl � 01`--`i �42G� � �'�~ � }�L1A� �' �ol ib � � �c �s � lx —�—� Z � 6 '�;J� � _ '�-�io I � ��' $ N.E. IOTH. 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LITTLE I "� Ac. _ � � �7 � ~ �) ' I.o3Ac �•93Ac. 1c.toB � ' i0�' 8 U x .a f� - '� ""�� 6 5 i _ 4 _ 3 R L 1� A E�' A�� , Y ANA � .. � 3 2 � � � � ��;• 6 ; 1 !D�, � ..K ��,... ES7 ES� U T . F S N ` _, ' 1� �-- �t - - -- --f'- -•-- - c9 s- c° � � Ac.' 71 5 : 6 � : �1 � ��7 r�.cr -r 8 IOo � bll�. � , �� $ Il . 321 �r so �! �u._ _L�_ �O� � �1 '- —'2I.t�- ��20- ' �- �d�' zS.Xr � � q I� � Ia 19 �' y ►1 � � -cs--l _ � � _ e ` ^ ' �- 0.99Ac� �i �rb � � M - � �� °' 6 5 4 3 2 1 � 0.10Ac. � � �r, ay Rtr �2 uHR �N r� � � �� ':e iss.la - - -� � .�,,� ti� Q � TR. ` �Toa.-ss-_-faa=` -- „��a.-,� ' - :�s s N.E.. � M �A� ��D�� / �I � „ �B � 0.42 Ac. x � � J' ' � �] �t iz�a �� ✓soes »t .�� a_!S �"� � .� '�a �sd� �* � � -=---- � �__= o.46Ac. '-' . H � �1; y: � , 1 !; � „ 3, � o ox � N- u � ,� � I . � )16.38 ioo x�+ ro es �c �`' � � T— 121�.�L � I'. �2 II $ ` �'� � � II- izia.» � �y► �l ty O �c.x^ TR'. , . °----- --- B~ K � w a n i s . 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Ev .�� r�u�%�y �<' �� `��AkF�� 1,�� ",��'�i ` �i^ .�-�_ ° �� . > ..,, o q '� ` AQp.' t� �'" `' 1 �`' , � �� 4 =','� rtt �r Y.`� e *� • •�� ''' S �:,�' �Yr'� �4 -rT � M .r� �'G+ '�{ �1 ad ._ __a t ""' , ��C 7 1. -- �— � 2, '-,. AY'e �,----- - :- - `°�t- ----- w a ��BM e,.'.i 27'30„ '� � 0. ,�- -- - -°=----•-- ,- :2 � -- -_ , BM�B2-- �49G-a.-- � � +. �ia �A B f �' ' : i '+ — �j�r k`�� 1 K'"`�. 3 a�+3�°jsGt4 -�� _: �' VI .� # .�' 1�' '` ;��, :� ,,;,, ' :'� �o : � �� - - � :t : r• �w��+xb,� �'s , y ', :�;,� AkFwi ��p�, e �jsw� e.i *�`��y,�R}�� "� � '�. 1 � �A �r... � �'t fs'IR �`"�'' l' .1 ".. {� .�', , nmc � 3jt��a� I� f � �' a •: , � P 68 1�'t�.�.>� �pfPELINE` A�C� �`.�t��#`�� { � s�•; �" Nme+ � 'P. ��t' 2'-- -'` � � <[ ,i' � � tii � 492 '� "u� � Urt � � ��- ` � ��. '� `d� r �1-. ��.. �`..} ' ,� '� � y�, � �, � � ti � `� � ��'�'^;� �'��`"'� �'F,�Ro `� '�. -- �. , ' ' i � f�, �p. '1'' '�, � '�$k•� "�tl �ui` '�'p Agf? a;.:.i.+ ,r.?i , •�\`�`�i�s�'.� ,yh, `N �_ �-, Y � w ��i4 '��^'�♦ .� � y�''�� s� �� F '�� , ��,'; ;: .' , � _ '� O��. �x Q ��AgB�+� V�'� Y�` `�• 1� .r C� �i �, �' � • 1� � �� 1w � 4� r ,,s�( •i ,`�, Tt K , e�A µ , �� ` �.� eG1. �t ��;��1��. 1��7�� -� '� _� ` 93' �m .i;. -- - � 4� ;,- ��'�irr{• Tk�,,. �,� 443 - • - ---- --- f-'`s ----�j� �''- �, v!, ` t � .' ' - . • , .. � , . . �ArH - � � v . . 11. PRELIMINARY CONDITIONS SUMMARY CORE REQUIREMENT #l: DISCHARGE AT NATURAL LOCATION The allowable outflow from the site will be discharged to its natural location. The Leve) 2 flow control is calculated to match the developed peak discharge rates to the existing site coiidition peak discharge rates for tl�e 2-year and 10-year return periods. CORE REQUIREMENTS #2: OFF-SITE ANALYSIS Refer to off-site analysis on subsequent pages. CORE REQUIREMENTS #3: FLOW CONTROL Preliminary calculations are provided on subsequent pages addressing runoff rate. The sizing for detention and runoffcontrol facility and its routing calculations are included in this report. CORE REQUIREMENTS #4: CONVEYANCE SY5TEM The conveyance system will be designed using the rational method as presented in the King County 1998 SWM Manual. CORE REQUIREMENTS #5: EROSION/SEDIMEN�'ATION CONTROL PLAN The 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 Sedimentatioi� traps will be considered during construction of plat improvements. - CORE REQUIREMENTS #6: MAINTENANCE AND OPERATION N/A CORE REQUIREMENTS #7: FINANCIAL GUARANTEES AND LIABILITY' N/A CORE REQUIREMENTS #8 WATER QUALITY The water quality facility proposed for this project consists of a wet-vault. Pg. - 4 1 SWM SPECIAL REQUIREMENTS Special Requirements #1: Adopted Area Specific Requirements. The site drains to the Cedar River via the Maplewood Creek Sub-basin. Special Requirements #2: Delineation of the 100-yr Flood Plain. NA Special Requirements #3: Flood Protection Facilities. NA Special Requirements #4: Source Gontrol. NA � Special Requirements #5: Oil Control NA h--- � Pg. - 5 III OFF-SITE ANALYSIS UPSTREAM The site is the situated west of Union Avenue NE, north of the Kiswanis Park. 1 here exi.s�t.��a snurll ntf-site arec� coiltribrrt�ng t�the site, apprnxinzately 0.2�f�rcres, sitlrated southwest of the s•ite. 7itis re�ort tivill uc�c�i•es.�• the bastft area of 1.97 acres. The sheet flows drains easterly toward existing storm system in Union Avenue NE. . DOWNSTREAM Surface runoff from the proposed plat sheet flows east to Union Avenue NE. The runoff then travels south via existing under ground storm system in Union, and directs the flow to NE 4`�' Street, approximately quarter of mile from the site. The flow crosses NE 4`�' in the southeasterly direction into,a more defined swale. 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' ' � r -_ ru,�e-e � i3rne � 'p ..�i, � ^7 _ nr � ��l i � ; � FLOW CONTROL AND WATER QUALITY The Plat subdivision Level 2 Analysis will be based on the 1998 KCSWDM using the Level 2 flow control method to match '/2 the 2 year through the 50 year developed peak flows to the existing conditions peak flow rates. The basin area consisting of developing 1.73 acres of plat and small off-site area of approximately 0.24 acres contributing to the site. The development includes asphalt paving, driveways, houses and landscaping. The flow from drainage basin is directed through a detentior�/wet-vault for peak flow control and Water Quality measures. The roof runoff from the new houses will be collected in catch basin pick-ups and directed to the conveyance system. Pre-Developed Conditions , Forest 0.06 acres forested �I Grass - 0.06 acres grass �, � Grass � 1.64 acres � Impervious 0.21 acres "l'otal Area 1.97 Acres Post—Developed � 1�orest 0.06 acres Grass/Landscaling 0.60 acres For this Level 2 analysis of the 10 lot preliminary plat we will use 4000 SF/lot per Section 3.2.2. 1 KCSWDM), or 75°/a of the lot whichever is less. Lot Area. Impervious 1 6226 4000 Sf 2 5579 4000 SF 3 6019 4000 SF 4 7066 4000 SF 5 5822 4000 SF 6 4573 3430 SF 7 4500 3375 SF 8 4500 3375 SF 9 4500 3375 SF 10 6527 4000 SF Total 37555 SF = 0.86 acres Right Of Way = 15694 sf 0.36 acres Easement = 4000 sf 0.09 acres Total Impervious = 1.31 acres Pg. - 8 ' The above information will be used in the King County KCRTS computer program to establish the existing and proposed time series for the peak flow analysis. The calculated vault will be 73'x 39' x 5.0' of live storage depth, inside measure. There will be a wetpool volume for water quality within the same vault as calculated below. - WATER QUAI.ITY The wet-vault permanent pool will be sized per section 6.4.1.1, page 6-68 of the KCSWDM. The V� _ (0.9A; + 025A,g + O.lOAu�+O.OIA�) x (R/12) V� = volume of runoff from mean annual storm A; = area of impervious SF A,�= area of till grass soil covered with grass SF A,��= area of till forest soil covered with forest SF A„ = area of outwash soil covered with grass or forest SF R = rainfall from mean annual storm (figure 6.4.1.A),= 0.47" , � S ��c,.,�-,- -:;; -� r o ' > >"' '° � , V�_ (0.9(49,926) + 0.25(24,830) )x (0.47/12) ��/ . :7 � . > >�� z�� s�� _ (44847 + 6208) 0.47/12 =(51055)(0.47/12) = 2000 CF Vb = 3(2000) = 6000 CF �, -- �_ � : � � , - � . � , �� The required depth of the wetpool is 6000 CF/(73x39) = 2.11' calculated. Per the King County SWDM the depth of the wetpool should be 3', with 1' average depth for sediment storage. This volume will be accommodated within the bottom of the detention/wetvault to be designed and constructed in the southeast corner of this proposed lO lot subdivision. The overall inside depth of the vault will have to be: 1' sediment storage 3' dead storage for the wetpool 5.0' live storage for detention 0_5' top clearance 9.5' total depth B10-F1�.'�'$ATION We have accommodated for the water quality within the wet-vault as designed above. STORM WATER PEAK FLOW CONTROL: Reter to the following pages for the wet-vault sizing calculations. Pg. - 9 ' savannah2.txt KCRTS Command CREATE a new Time Series ------------------------ Production of Runoff Time series Project Location : Sea-Tac Computing Series : predev.tsf Regional Scale Factor : 1.00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF60R. rnf . Till Forest 0.06 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60R. rnf . Till Grass 1.70 acres '� Loading Time Series File:C:\KC_SWDM\KC_DATA\STE160R. rnf . Impervious 0.21 acres -------------- Total Area : 1.97 acres Peak Discharge: 0.463 CFs at 6:00 on �an 9 in vear 8 storing Time Series File:predev.tsf . Time series Computed KCRTS Command CREATE a new Time Series ------------------------ , Production of Runoff Time series Project Location : Sea-Tac computing series : dev.tsf Regional Scale Factor : 1.00 Data Type : Reduced creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF60R. rnf . Till Forest 0.06 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60R. rnf . Till Grass 0.60 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STE160R. rnf . Impervious 1. 31 acres -------------- Total Area : 1.97 acres Peak Discharge: 0.750 CFS at 6:00 on ]an 9 in Year 8 storing Time series File:dev.tsf . Time series Computed KCRTS Command Enter the Analysis TOOLS Module ------------------------------- Analysis Tools Command ---------------------- Compute PEAKS and Flow Frequencies ---------------------------------- Loading Stage/Discharge curve:dev. tsf . Flow Frequency Analysis -------------------------------------------------------- Time series File:dev.tsf Project Location:5ea-Tac Frequencies & Peaks saved to File:dev.pks . Analysis Tools Command ---------------------- Page 10 ' SAVANNAH AT THE PARK SUBDIVISION Flow Frequency Analysis Time Series File:predev.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 � G.205 4 2/09/Ol 2:00 0.463 1 1�0.00 0. 990 0. 124 6 1/OS/02 16:00 0.256 2 25. 00 0. 960 0.256 2 2/27/03 7:00 0.213 3 10. 00 0. 900 0. 084 8 8/26/04 2:00 0.205 4 5.00 0. 800 0. 118 7 1/05/05 8:00 0. 194 5 3.00 0. 667 0.213 3 1/18/06 16:00 0. 124 6 2. 00 0.500 , 0. 194 5 11/24/06 3:00 0. 11b 7 1.30 0.231 0.463 1 1/09/08 6:00 0.084 8 1. 10 0.091 � Computed Peaks 0. 394 50. 00 0. 980 Elow Frequency lnalysis Time Series File:dev.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. 373 6 2/09/O1 2:00 0.750 1 100.00 n. 99C; 0. 308 8 1/OS/02 16:00 0.491 2 25. 00 u. 960 i 0.448 3 2/27/03 7:00 0.448 3 "10.00 0. 90U 0. 338 7 8/26/04 2:00 0.405 4 5. 00 0. 800 0. 405 4 10/28/04 16:00 0. 397 5 3.00 0. 667 0. 397 5 1/18/06 16:00 0. 373 6 2.00 0. 5U0 0.491 2 10/26/06 0:00 0. 338 7 1.30 0.231 0.750 1 1/09/08 6:00 0.308 8 1. 10 0. 091 Computed Peaks 0.664 50. 00 0. 980 DETENTION REQUIREMEPITS: DIFFERENCE BETWEEI•d 100-YERR PEAK FLO[^7S : 0.750 - 0.463 = 0.287 CFS > 0. 1 CFS THEREFORE DETENTION IS REQUIRED. FIRST INTERVAL = 50� OF 2-YR FLW = 0. 5 * 0. 124 = 0. 062 II�ITERVAL SIZE _ (50-YR-50'�OF 2-YR} /36-1 _ (0. 394-v. 062) /35 = 0.0092 Qmaz = 4/3 * 50'= Or ��-'iR = 4/3 * O. u62 = 0. 0825 Pg. - 11 ' � o i target.dur � �� I �! N ; - -- - ', O ' �� O N_ , • - --- -_ _ _ - O �� . ,i. � � � � �, n ---- -- -- �- ----- ------ ------ .-I.- O U � � I � � � c� (/) N ------ - ,_ � � __-- � � �r ` � O .._ Y. --"-___.-_ _.. . . . ___ ... O I `, \ i \b � ,. o I - _ __ _ _ . 0 o '' 0 � , i , , _ i � , i - --;- T- i- ,��--�_ _��r�rr�__�- T -i ; i 1_.1 � - ; i i i i i i 10 -5 10 -4 10 �3 10 �2 1� � �� Pg. — 1 2 ' Probability Exceedence Rctcntion;Uetention Facility `Pype of Facility: Detention Vault Facility Length: 71. 00 ft Eacility Width: 40.00 ft Eacility Area: 2840. sq. ft Eticctiv� Storage Depth: 5. 00 ft stage 0 Elevation: 0.00 ft Stor ge Volume: 14200. cu. ft �iser Head: 5.00 ft Riser Diameter: 12.00 inches Idumber of orifices: 2 Full Head Pipe C�rifice # Height Diameter Discharge Diameter �ft) (in) (CFS) (in) l 0. 00 1.20� � 0.087 :' 3. 00 , 1.60 � 0.098 4.0 Top Notch Weir: None Outflow Rating Curve: None �tage Elevation Storage Discharge Percolation ( ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) '� . 00 0. 00 0. 0.000 0.000 0.00 �i , U1 0.01 28. 0. 001 0.004 0. 00 i . U3 0. 03 85. 0. 002 0. 006 0. 00 �i . u4 0. 04 119. 0. 003 0. 008 0.00 i�. 05 0. 05 142. 0. 003 0.009 0.00 U. 06 0. 06 170. 0.004 0.010 0.00 0. 08 0. 08 227. 0.005 0.011 0.00 C,. 05 0.09 256. 0. 006 0.012 0.00 ��. 10 0. 10 284. 0. 007 0.012 0.00 �_!.20 0.20 568. 0.013 0.017 0.00 U. 30 0. 30 852. 0.020 0.021 0.00 u. 40 0.40 1136. 0.026 0. 025 0.00 [i , 50 0.50 1420. 0.033 0.028 0.00 ii . 60 0.60 1709. 0.039 0. 030 0. 00 �i .70 0.70 1988. 0.046 0. 033 0. 00 0. 80 0.80 2272. 0.052 0. 035 0.00 u. 90 0. 90 2556. 0.059 0.037 0.00 1 . 00 1. 00 2840. 0.065 0.039 0. 00 1. 1G 1. 10 3124. 0.072 0. 091 0. 00 1.20 1.20 3408. 0.078 0. 093 0.00 1 . 30 1 . 30 3692. 0.085 0.045 0.00 � 1.40 1. 40 3976. 0.091 0.046 0. 00 1. 50 1. 50 4260. 0.096 0. 048 0.00 1.60 1. 60 4544. 0. 104 0. 049 0.00 1.70 1.70 4828. 0. 111 0.051 0.00 1. 80 1. 80 5112. 0. 117 0.052 0.00 1. 90 1. 90 5396. 0. 124 0.059 0.00 2. 00 2. 00 5680. 0. 130 0.055 0. 00 2. 10 2. 10 5964. 0. 137 0. 057 0. 00 2.20 2.20 6248. 0. 143 0.058 0. 00 Pg. - 13 ' 2.30 2.30 6532. 0. 150 0.059 0. 00 2.40 2.40 6816. 0. 156 0.061 0. 00 2.50 2. 50 7100. 0.163 0.062 0. 00 2. 60 2.60 7384. 0. 170 0.063 0. 00 2.70 2. 70 7b68. 0. 176 0.064 0.00 2. 80 2. 80 7952. 0. 183 0. 065 0. 00 2. 90 2. 90 8236. 0. 189 0.067 0.00 3. 00 3.00 8520. 0. 196 0. 068 0. 00 3. 02 3. 02 8577. 0. 197 0.068 0. 00 3.03 3. 03 8605. 0. 198 0. 070 0. 00 3. 05 3. 05 8662. 0. 199 0. 073 0. 00 3. 07 3. 07 8719. 0.200 0. 077 0.00 3.08 3. 08 8747. 0.201 0.082 0. 00 3. 10 3. 10 8804 . 0.202 0.088 0. 00 3. 12 3. 12 8861. 0.203 0.093 0. 00 3. 13 3. 13 8889. 0.204 0. 094 0. 00 3. 15 3. 15 8946. 0.205 0.096 0. 00 3.25 3.25 9230. 0.212 0. 105 0. 00 3. 35 3. 35 9514. 0.218 0. 113 0. 00 3. 95 3. 45 9798. 0.225 0. 119 0.00 3. 55 3. 55 10082. 0.231 0. 125 0.00 3. 65 3. 65 10366. 0.238 0. 131 0.00 3.75 3.75 10650. 0.244 0. 136 0.00 3. 65 3. 85 10939. 0.251 0. 141 0. 00 3. 95 3. 95 11218. 0.258 0. 145 0.00 4 . 05 4 . 05 11502. 0.264 0. 150 0. 00 4 . 15 4 . 15 11786. 0.271 0. 154 0.00 � 4 .25 4 .25 12070. 0.277 0. 158 0. 00 4 . 35 4 . 35 12354. 0.284 0. 162 0. 00 4 . 45 4 . 45 12638. 0.290 0. 166 0. 00 9 . 55 4.55 12922 . 0.297 0. 170 0. 00 9 . 05 4. 65 13206. 0.303 0. 173 0.00 4.75 4 .75 13490. 0. 310 0. 177 0. 00 4 . 85 4 . 85 13774. 0.316 0. 180 0.00 4 . 95 4 . 95 14058. 0. 323 0. 184 0.00 5. 00 5. 00 14200. 0.326 0. 186 0.00 5. 10 5. 10 14484 . 0. 333 0.497 0. 00 5.20 5.20 14768. 0.339 1 .060 0.00 5. 30 5.30 15052. 0.346 1. 800 0. 00 5.40 5. 40 15336. 0.352 2.590 0. 00 5. 50 5. 50 15620. 0.359 2. 880 0.00 5. 60 5. 60 15909. 0. 365 3. 130 0. 00 5. 70 5.70 16188. 0.372 3. 370 0.00 5. 80 5. 80 16472. 0.378 3. 590 0.00 5.90 5. 90 16756. 0. 385 3. 800 0.00 6. OU 6. 00 17040. 0.391 4.000 0. 00 6. 10 6. 10 17324 . 0. 398 4. 190 0.00 6.20 6.20 17608. 0.409 4.360 0. 00 6.30 6.30 17892. 0.411 4.540 0.00 6.40 6.40 18176. 0.417 4 .700 0.00 6. 50 6.50 18460. 0.424 4 . 860 0.00 6. 60 6. 6a 18744. 0.430 5. 020 0.00 6. 70 6.70 19028. 0.437 5. 170 0. 00 6. 80 6. 80 19312. 0.443 5.310 0. 00 6. 90 6. 90 19596. 0. 450 5.450 0.00 Pg. - 1 4 ' 7.00 7.00 19880. 0.456 5.590 0.00 Hyd Inflow outflow Peak Storage Target Calc Stage Elev (Cu-Ft) (Ac-Ft) 1 0.75 0. 46 0. 49 5. 10 5. 10 14480. 0.332 2 0. 37 ******* 0. 18 4.74 4.74 13470. 0.309 3 0.38 ******* 0. 17 4.49 4.49 12761. 0.293 4 0.40 ******* 0. 16 4. 19 4. 19 11913. 0.273 5 0.45 ******* 0. 19 3.85 3. 85 10932. 0.251 6 0.29 ******* 0.08 3.07 3. 07 8723. 0.200 7 0. 31 ******* 0. 06 2.01 2.01 5699. 0. 131 8 0. 34 ******* 0. 05 1.57 1.57 4955. 0. 102 � Route Time Series through Facility ' Inflow Time Series File:dCv. tsf Outflow Time Series File: r i �:r Inflow/Outflow Analysis Peak Inflow Discharge: U. 750 CFS at 6: u0 on Jan 5 in Year ts ' Peak Outflow Discharge: 0.493 CFS at 9:00 on Jan 9 in Year 8 Peak Reservoir Stage: 5.10 Ft Peak Reservoir Elev: 5.10 Ft Peak Reservoir Storage: 14980. Cu-Ft . C;. 3j2 Ac-Ft � Flow L�uration from Tirne Series File: rdout. tsf- �utoff Count Frequency CDE Exceedence Probability CFS k $ 0.003 43387 70.755 70.755 29.245 0.292E+00 0.007 3596 5.864 76.619 23.381 0.234E+00 0.012 3392 5.450 82.069 17. 931 0. 179E+00 0. 017 2875 9 .689 86.758 13.292 0. 132E+00 0.022 2277 3.713 90.471 9.529 0.953E-01 0.027 1588 2.590 93.061 6. 939 0.694E-01 0.032 1292 2. 107 95."168 4.832 0. 483E-01 0.037 984 1.605 96.773 3.227 0.323E-u1 0.042 645 1. 052 97.825 2. 175 0.218E-u1 0.047 425 0. 693 98.518 1.482 0. 148E-01 0.052 340 G. 554 99.072 0. 928 0. 928E-��2 0.057 149 0.293 99.315 0.685 0. 685E-02 0.062 130 0.212 99.527 0.473 0. 473E-02 0.067 111 0.181 99.708 0.292 0.292E-02 0.072 54 0. 088 99.796 0.204 0.209E-u2 0.077 11 0.018 99.819 0. 186 0. 186E-U2 0.082 5 0.008 99.822 0. 178 0. 178E-02 0.087 2 0.003 99.826 0.174 0. 174E-u2 0.092 1 0.002 99.827 0. 173 0. 173E-u2 0. 097 8 0. 013 99. 640 0. 160 0. 160E-02 0. 101 12 0.020 99.860 0. 140 0. 140E-02 0. 106 7 0.011 99.871 0. 129 0. 129E-u2 0. 111 6 0.010 99.881 0. 119 0. 119E-02 0. 116 5 0.008 99. 889 0. 111 0. 111E-02 u. 121 3 U. G05 55. 894 0. 106 0. 106E-U2 Pg. - 15 ' �. 126 9 0. 015 99. 909 0. 091 0. 913E-03 G. 131 3 0.005 99. 914 0. 086 0. 864E-03 �. 136 9 0.015 99. 928 0.072 0.718E-03 �=!. 141 8 0.013 99. 941 0.059 0.587E-03 �:�. 196 7 0.011 99.953 0.047 0.473E-03 ��. 151 5 0.008 99.961 0.039 0.391E-03 �_�. 156 8 0.013 99. 974 0.026 0.261E-03 ��. 161 3 0.005 99. 979 0.021 0.212E-03 !;. 166 4 0.007 99. 985 0.015 0. 147E-03 �-. 171 4 0.007 99.992 0.008 0. 615E-04 �; . i76 3 0.005 99. 997 0.003 0.326E-04 I�ur;at ion Comparison Anaylsis base File: predev.tsf IJew File: rdout. tsf �.'i,c .�t t [Ji�i t � : Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- C�,t�tf Base New rChange Probability Base New '6Change u. u63 I 0. 54E-02 0. 43E-02 -20. 1 � 0. 54E-02 0.063 0.060 -9 . 6 �� 8 I 0. 33E-02 0. 18E-02 -94 . 0 � 0. 33E-02 0.078 0. 066 -15. 5 G. u93 � 0. 19E-02 0. 17E-02 -9.5 � 0. 19E-02 0.093 0. 075 -19. 3 �-�. 108 � 0. 13E-02 0. 13E-02 -4. 9 � 0. 13E-02 0. 108 0. 104 -3.0 i�, 123 � 0. 86E-03 O. 10E-02 18.9 � 0.86E-03 0. 123 0. 131 6.8 �. 138 � 0.60E-03 0. 67E-03 10. 8 � 0. 60E-03 0. 138 0. 141 2.4 ��. 152 � 0. 36E-03 0. 38E-03 4 .5 � 0. 36E-03 0. 152 0. 153 0.4 ��. 1.67 � 0.29E-03 0. 13E-03 -55. 6 � 0.29E-03 0. 167 0. 155 -7.4 :'• 182 I 0. 16E-03 O.00E+00 -100.0 � 0. 16E-03 0. 182 0. 165 -9.7 �.�. 197 � 0. 98E-04 O.00E+00 -100.0 � 0.98E-04 0. 197 0. 170 -13.9 i,.212 I 0.�9E-04 O. 00E+00 -100.0 � 0.49E-04 0.212 0. 173 -18.5 ��.227 � 0. 33E-04 O. 00E+00 -100. 0 � 0. 33E-09 0.227 0. 176 -22. 4 �i.242 � 0. 16E-04 O. 00E+00 -100.0 � 0. 16E-04 0.242 0. 177 -27 . 1 t�t�;�:i�num positive excursion = 0.008 cfs ( 6. 8$) occurring at 0. 123 cfs on the Base Data:predev.tsf and at 0. 131 cfs on the New Data:rdout.tsf Nlaximum negative excursion = 0.079 cfs (-30.81�) .�ccurr:iny at 0.255 r_fs on the Base Data:predev. tsf �ri:1 �; 0. 1 �l�r cl 5 :�n t_l�t I�]�1�� Data: rdout. t�f Route Time Series through Facility Inflow Time Series File:dev.tsf Cutflow Time Series File: rdout lnrl.ow/Outflow Analysis Peak Inflow Discharge: 0.750 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.493 CFS at 9: 00 on Jan 9 in Year 8 Peak Reservoir Stage: 5.10 Ft Peak Reservoir Elev: 5.10 Ft Peak Reservoir Storage: 14980. Cu-Ft . 0.332 Ac-Ft Flow Duration from Time Series File:rdout.tsf Pg. - 16 ' � N _ _ _ ___ _--- ------__ _- _ � o I rdout.dur - target.dur � _ , _ � ,-� � , CV- ---- ,_ _ _ _ - _ ------ _ - - O I ' �' ' � O , �� N '-_ ----_- — .� - ___ _- -- - - ---_ _— __ O _ ' , � j�� R �� i - - � _ —. � - ��, i � � _ . --- -- - - ____ - --- -- _ __ .--- -- - -- , , �� o ��,� U � �-- a� �� rn � � � c� � N ,°�` (n _ � ,>.--- _ _ -- - _ _ ,^_ _ _ _ - _ -- ---- _- --- ---- J O �i �� _, ! '�t' i ;�;!�' 1,`, <^>� � X. 00 �t;. O- _ __ _ _ - --- - _ ____ __ - ----�';� \�--- -_ _ __ _ O � , Y; �, � 00 _- -- <J, - --- < � %'� � � O '�<--_ a r � II � I 10� .4 --7- _� I 1- T 1�1 1 ��T�T�---��-��TfT�—��_�l_I_i_i.�_�T_ _ _� I I ! I I I -5 �� -a 10 -s �� -2 �� -� ��o Pg. - 17 ' Probability Exceedence V. CONVEYANC� S�'STEM ANALYSIS AND DESIGN 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 0.67cfs. The capacity of a l 2- inch pipe with 1.0% slope is able to handle 3.71 cfs. King County Surface Water Design Manual 1998 requires to the conveyance pipes to be designed based on 25-year storm. I , Pg. - 1 8 ' 1 ' � ' tmp#l.txt Manning Pipe calculator Given Input Data: � shape . . . . . . . . . . . . . . . . . . . . . . . . . . Circular � solving for . . . . . . . . . . . . . . . . . . . . . oepth of Flow Diameter . . . . . . . . . . . . . . . . . . . . . . . . 12.0000 in Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 3. 7100 cfs slope . . . . . . . . . . . . . . . . . . . . . . . . 0.0100 ft/ft Manning's n . . . . . . . . . . . . . . . . . . . . . 0.0120 computed Results: Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4416 in Area . . . . . . . . . . . . . . . . . . . . . . . . . . 0.7854 ft2 wetted Area . . . . . . . . . . . . . . . . . . . . . 0.6629 ft2 wetted Perimeter . . . . . . . . . . . . . . . . 26.1803 in Perimeter . . . . . . . . . . . . . . . . . . . . . . . 37.6991 in velocity . . . . . . . . . . . . . . . . . . . . . 5. 5967 fps ', Hydraulic Radius . . . . . . . . . . . . . . . . 3.6461 in i Percent Full . . . . . . . . . . . . . . . . . . . . 78.6799 % Full flow Flowrate . . . . . . . . . . . . . . 3.8597 cfs Full flow velocity . . . . . . . . . . . . . . 4.9143 fps Critical Information Critical depth . . . . . . . . . . . . . . . . . . 10.3296 in critical slope . . . . . . . . . . . . . . . . . 0.0070 ft/ft Critical velocity . . . . . . . . . . . . . . . 4.9237 fps Critical area . . . . . . . . . . . . . . . . . . . 0.7535 ft2 critical Perimeter . . . . . . . . . . . . . 27.5087 in critical hydraulic radius . . . . . . . 3.9443 in critical top width . . . . . . . . . . . . . . 12.0000 in Specific energy . . . . . . . . . . . . . . . . . 1.2628 ft � Minimum energy. : : : : : : : : : : : : : : : : : : 1.2912 ft Froude number 1.2442 Flow condition . . . . . . . . . . . . . . . . . . Supercritical Pg . -1 `) ' VI. SPECIAL REPORTS AND STUDIES VII. BAS1N AND OTHBR COMMUNITY AREAS VIII. OTHER PERMITS Pg. -2 0 ' IX. TEMPORARY EROSION The Temporary Erosion Plan will be designed to the 1998 King County Surface Water Design Manual, Appendix D. A rock construction entrance will be shown on the plans at the entrance road to the site. The detail will be included on the plans. A silt fence is to be erected at the bottom of slopes. TEMPORARY SEDIMENT TRAP Traps should be constructed on the south side of the entrance road for about 1.73 acres of development. The surface area of the trap: SA= 2 X (QZ/0.00096)= 2080 sf/cfs of the 2yr developed peak The 2 year developed peak for the site is 0.33 cfs. Sediment Pond peak flow= 0.33 cfs, SA= 0.33(2080) = 686 SF �I, Try a pond with 3' of sediment depth that measures 19' x 40' at the top of the weir= 760 square feet. I' SEDIMENT TRAP #1 Depth Elev. Dimension Top of Benn 4.00' 420.00 25'x46' Top of Berm 3.00' 419.00 19'x40' weir— 760 SF 2.00' 418.00 13'x34' 1.00' 417.00 7'x2 8' 0.00' 416.00 1'x22' Bottom of sediment storage Pg. - 21 ' RESIDENTIAL STREETS LIGHTINGS FOR SAVANNAH AT THE PARK GENERAL INFORMATION: CONDUCTOR STREET CIRCUIT USE-RHH(XLP) PHOTO CELL CIRCUIT THHN CONUCTOR INSULATION 600 VOLTS SERVICE CONTRACTOR CABINET 120/240 VOLTS 3-WIRE SERVICE PHOTO CELL CONTROL 240 VOLTS 2-WIRE POLE MOUNTING HEIGHT 25 FEET LAMP VOLTAGE 100 WATTS UNIFORMITY RATIO 0.2 FOOT-CANDLE ' LUMINAIRE GE MODEL N0. N-250A2 LUMINAIRE SPECIFICATIONS REFER TO ATfACHED SPECIFICATIOINS DETERMINE LAMP AND BALLAST OPERATION CURRENT CIRCUIT NO. 1 LINE CURRENT DROP 0.76 AMPS FOR 240 VOLTS TOTAL LINE DROP LAMP AMPS POLES AMP-TOTAL 1 0.76 2 1.52 2 0.76 1 0.76 DETERMINE VOLTAGE DROP USING AWG WIRE SIZE#8 CIRCUIT NO 1 LAMP AMPS WIRE LENGTH RES-OHM CONST. DROP WIRE # I � 1 1.52 2 81.5 0.66 1000 0.163522 8 2 0.76 2 197 0.66 10�0 0.19763 8 TOTAL 0.361152 PERCENTAGE OF VOLTAGE DROP 0.001505 0.15048 % OK IT IS LESS THAN 5% DROP Pg. - 22 ' �,,� �7i2005 08:41 FAX 4252510625 TOLTMSA E:�GI:VEERS �001 i � � i rx. r��ox.��ERoszorr � The Temporary Erosion Plan will be designed to the 1998 King County Surface 1?Vater Design Manual; Appendix D. A rock construction entrance will be showrt on the plans at the entrance road to the site. The detail will be included on the plans. A silt fence is to be erected ax the bottom of slopes. TEMPORARY SEDIlVIENT TRAP Traps should be constructed on the south side of the entrance road for about 1.73 acres of development. � The surface area of t�e trap: SA=2 X(Q�/0.00096)= 2080 sf/cfs of the 2yr developed peak The 2 year developed peak for the site is 0.373 cfs. � i Sediment Pond peak flow=0 373 cfs, SA=0.373(2080)= 775 SF ' � Try a pond with 3' of sediment depth that measures 20' x 40' at the top of the weir=800 square � feet. SEDIlvlENT TR.AP #1 � Depfh Elev. Dimension ; Top of Berm 4.00' 420.00 26'x46' Top ofBerm � i 3.00' 419.00 20'x40' weir—76� SF � 2.00' 418.00 14'x34' ' i.00' 4i�.00 g�s' � 0.00' 416.00 2'�2' Bottom of sediment storage � I � I . Post-it'D Fax Note 7671 �a�9 J O� pa°ges�Z i � I zo R�O/I QVI?i! From �0�,/ %GU/J?4 i Ga�oePt. � �� Co. i Phone# Phone k �zf�D� " Fax it 5[z y�[�.313- 72 y� Fax# '�Zd�/- O 62� ' i I , 09,i07/2005 08:�1 FAy 4252510625 TOLTM�I ENGI�EERS (�002 � The above information will be used in the King County KCRTS computer program to establish ' the existing and proposed time series for the peak flow analysis. The calculated vault will be 71'x 40' x 5.0' of live storage depth, inside measure. There will be a wetpool volume for water ' quality within the same vault as calculated below. � . � WATER QUALITY ` The wet-vault permane�nt pool will be sized per section 6.4.1.1, page 6-68 ofthe KCSWDM. � The V�= (0.9A; + 0.25A��+ O.l0A�+0.OlAo) x (R/12) V�= volume of runoff from mean annual storm A;= area of impervious SF � A:g= azea of till grass soil covered with grass SF Atr= area of tili forest soil covered with forest SF ' A4 = area of outwash soil covered with grass or forest S�F R = rainfall from mean annual storm (figure 6.4.1.A)=0.47" I I V�_ (0.9(52,249) �0.25(26,136)+0.10(2613)) x (0.47/12) _ (51,524+ 6�34+261)0.47/12= (58,319)(0.47/12)=2284 CF Vb = 3(2284) =6852 C� I I The required depth of the wetpool is 6852 CFI(71x40) =2.4' calculated. Available storage is � , OK. Per the King County SWDM the depth of the wetpooi shouid be 3', with 1' average depth � for sediment storage. , i i I This volume will be accommodated within the bottom of the detention/wetvault to be designed I and constructed in the southeast corner of this proposed lO lot subdxvision. I � The overall inside depth of the vault will have to be: 1' sediment storage ; 3' dead storage for the wetpool ; 5.0' live storage for detention ' ; 0_5' top clearance � ', 9.5' total depth I � WET-VAULT � We have accommodated for the water quality within the we�t-vault as designed above. STORM WATBR PEAK FLOW CONTROL: Refer to the following pages for the wet-vault sizing calculations. ' Pg. - 9 � i