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Home My WebLink About03177 - Technical Information Report - Drainage . .�AEGER �l`IC Il`IEERIItiiC t -- �� -�� 9419 S. 204 P�.ACE - KENT, WASHINGTON 98031 PHONE (253) 850-0934 F�►x (253) 850-0155 December 18, 2003 Revised March 20, 2004 Revised June 21, 2004 `��Y�� JUN 2 2 2!'�?4 � DRAINAGE REPO� URBAN CRAFT MIXED U�►� PlR�:1�'('�1' 3410 NE 4th STRE� RFN'T'nN_ V4- rr��;i��;�L: Urban Craft Lee Johnson, (�len L?:�� ::� 3232 24�' Ave. W. Seattle, WA. 98199 (206) 328-5071 " � �•��; ��'��t�s� =� 1 '�',t,�';; , �. ,,�. PREPARED BY: �'°' - - ., -�: , � �. James J. Jaeger, P.E. ��.�`s� C ' ''-4. .��12�� `4- �T7'OF RENT .�....�: ._ _.:�....., .._ -- REC OIV . _ ,. �� F4R qppR N�ED BY p�Al B �ArE: � � BY_��-DAtE; , � —��_-pA�E;��- �1 .,�� ' -� '�� '/ _ _ " � . t= ,Y; ; . � ��I TABLE OF CONTENTS I. OVERVIEW II. CORE DRAINAGE REQUIREMENTS III. OFFSITE DRAINAGE IV. PREDEVELOPED DRAINAGE V. DEVELOPED DRAINAGE VI. CONVEYANCE SYSTEM VII. EROSION CONTROL _ -� " I I. OVERVIEW� The proposed'plat consists of an existing commercial lot with a total area of 0.78 acres. proposed project will construct a mixed use building and parking lots/driveways. There are no existing structures on the lot, however it has been partially developed. There is an existing drainage system on the site, numerous other utilities and a large compacted gravel parking area. A previous project called "Bumstead Machine Building" was approved by the City. There are existing engineering plans dated 6/18/81 (plan file #1605), that are also approved. These plans show the droinage detention system that generally matches the surveyed as-built for the current lot condition. The access to the project will be from Olympia Ave. NE, along the east side of the property. The low area is along the west properfy line, towards the southwest corner along NE 4ih St. The existing drainage sheet flows to the southwest and either is collected by the existing drainage system or sheet flows off the site and onto the adjacent property to the west. Water, sewer and power/phone can be accessed from Olympia Ave. NE, but the water must be extended and the sanitary sewer must be rebuift along Olympia Ave. NE. All utilities exist within NE 4fh St. The existing driveway is connected to Olympia Ave. NE, all along the eost �i property line. Olympia Ave. NE is asphalt paved, but is not a developed ' street. The pavement width is approx. 22' in many places and there are no curbs or sidewalks. There is an existing drainage system within the shoulder of the street. NE 4th St. is fully improved with curb, gutter and sidewalks and full width pavement. It has City standard street lights and all utilities. It is classified as an arferial by the City. No direct access is proposed from NE 4+h St. The proposed access will be from three driveways connecting to Olympia Ave. NE. The property in its current condition has no trees. It had been cleared many years ago. Early USGS maps show a trailer park at this location. The parcel is primarily covered with compacted gravel, dirt and wild grass. There is an area of thick brambles along the north property line. The gravel area is quite large, measuring over 17,000 SF in area. The site slopes down #rom the northeast to the west and southwest. The existing slope across the majority of the parcel is approx. 1%. There is an area of approx. 15% slope in the norfheast corner of the site. This is the steepest slope on the properfy and is restricted to a small area in the northeast corner. There are no sensitive areas on this site. The proposed drainage will be collected by catch basins within the new parking and driveway areas and routed to a detention pipe. The pipe will be placed along the west and south property lines and will discharge into an existing catch basin within NE 4th St., near the southwest corner. The existing drainage system within the site includes approx. 100' of 24" detention pipe. This pipe and existing catch basins will be removed. Water quality enhancement for the site will be accomplished using a wet tank. This dead storage volume will be provided by the bottom half of the 60" diameter detention tank. The live storage will be above the dead storage within this pipe. The site soils are of the Alderwood series as mapped by the SCS soils survey. / . � � . -,- . - - � K(ng County Buliding and Land Development Dlvislon TECHNICAL INFORMATION REPORT (TIR) WORKSHEET - . . �- � - . . . � i � F' • • � �� ba.�. c� t I Project Owner � Project Name �, r T' Address 3 z3Z Z4 U7• $�o�- C Location � Phone � 32`a'�� 4 Township Z3 � ; Range �� I Project Engin�ee,r SalaM2S �T0.S�-�'r �ion ' Company C � �'»^ ' ,+,,, Project Size C� ��g f�►''� AC Address Ph�nP � � S� ��- �.-. ► ? i Upstream Drainage Basin Size �� f1C-AC � S S�- 4'�0 -I • • �•n;i • • �. ..�-1 � � Subdivision I � DOF/G HPA Q Shoreline Management � Short Subdivision I �j CO��p� � Rockery � Grading CI DOE Dam Safety 0 Structural Vaults �Commercial I Cj FEPf�A Floodplain � Other � Other i � COE 1'JeUa�ds 0 HPA ' --- «. � ,� i � �� - • i -i iCo�,,,,,.:n�.y �t� v� �R-�`!1 —.—_. I i � Drarage B2s;n � � � � �aX-. l�,{/'` ��'�— �—= � -- « ,� ..� ' CJ River _ � Flox�:a;n _. _ i ' � S;ream � 1"Jetlands __ !, � Criti�zl Stream Rezcn � Seeps�S�rings I �i Depressions�Sw�a�es � High Groundwa'er T�le C� Lake � Ground�ti�ater Recharge � C� S'eep Sior,es � Other __ ; !_.'� Lakesioer'Erosion Haza�d I��_ ..;. �. -< �-�� o:c�:s Erosio�Pc'er;i�l Eresi�.�e Ve!oci,es S�:.T�;:=.: ��-. `� D!a -�-'ln_ ___ --(�lo�.Q-r_o..--{�... - - — � . .F�S'-+' - - --��— ---- ---- _ — ---- -- - - ; --- , � — =�-`�-�- --------- ----- ------- - � � . �+dc:'�o��a;S`�eets A't�tcF�ed � ., 1: � � .. - King County Bullding and Land Development Dlvlsion � TECHNICAL INFORMATION REPORT (TIR) W�RKSHEET � . a . • � �� , . REFERENCE LIt�11TAT10WSlTE CONSTRAI�fT []• Ch.4-Downstream Analysis W � �1` � � � � � Additional Sheets Ariatched . -,�,� � . MINIMUM ESC REOUIREMEtv'TS MINIMUM ESC RE�UIREMENTS DURING CONSTRUCTION FOLlOWING CONSTRUCTION � Sedimentation Faalities ,� Stabilize Exposed Surfaoe i �Stabil'¢ed Constr�ction Entra�ce �" Remove and Restore Temporary ESC Fadlities I �' Perimeter Runofi Coniroi �� Clean and Remove All Silt and Debris i �Ciearing and Grading Restrict�ons � Ensure Operation ot Permanent Fadlities ' i �Cover PraC,ices � Flag Limits of NGPES i i .�Construction Sequence � 01her � � Other � �- « �- �, � Grass Linec Cha^,nel �Tank � Infiltration A"�e;hod c`Aralysis � Pipe System � Vault � Depression �'��j V�{ ; � O�en Channei � Enercy Diss�tor �, Flow�is�ersal Compensa:ion,T.liti�ation ' l� Dry Pond �J YJetla�d 0 Waiver oi Eliminated Si;e Storage � Wet Pond 0 Slream � Regional Detention Brief Descri�;ion cf Syslem O�ra;ion �� t� rv�� IVl'{� Ca.�V� D�NS . '�� i r�'� _l�0'�r1 '��, `�ro�� '�ow Y'�S�'t—1 c�Z�r Facility Related Si;e Limitations 0 Addilional Sheets Attatched neterence Faai;,y Liru;at�on I- I � �� _� � ' � Drainage Easement � Cast in Place V2u!1 n Other � Access Easement � Relaining VJa;t � Native Groxlh Protection Easement � . � Rockery>G'High � Tract L � Slructur2J on S:eep Slope (_] Other ti i- . - . -x - . > »- I or a civil engineer under my supervision have visited the site. Actusl ^ � sile conditions as observed were incorporated into this worksheet and the � � attatchments. To the best of my knowiedge the information provided _ �y here is accurate. s;v -�•� Z�j Tp3 / — _ III. OFFSITE DRAINAGE A. UPSTREAM DRAINAGE The upstream offsite dreainage contribution to this plat wili be minimal. The properfy has road frontages along the east side (Olympia Ave. NE) and along the south side (NE 4th St.). Both of these streets have existing drainage systems that will collect a11 of the runoff from those d'rrections. Runoff wiil not enter the site from either the south or east sides. The west side is the lowest side of the property and site runoff flows to this direc#ion. The norfh side is up-slope from the site. There will be a small amount of runoff from this direction. There is a residential development furfher to the north that collects its drainage and minimizes the upstream basin area. The runoff from this direction currently flows across the northwest porfion of the site and onto the adjacent property to the west. The proposed site development will include a short retaining wall and perimeter extruded curb that will block this off-site runoff from entering the north parking area and direct it to the west along the north property line to a landscaped area in the norfhwest corner. B. DOWNSTREAM DRAINAGE The drainage from the site will be discharged from the detention pipe and the flow restrictor at the southwest corner of the site. The drainage from the site will discharge infio an existing drainage pipe within NE 4+h St. This drainage pipe is a 12" pipe at a slope of approx. 1%. The pipe is located approx. 5' norfh of the road centerline. The 12" pipe runs for 150' to the west and enters a type 2 catch basin. This catch basin has a two discharge pipes, to the south and to the west. The pipe to the south is a newer pipe that runs south under NE 4ih St. and connects to a newer 27" dia. drainage system that runs along the south side of NE 4th St. The 12" outlet pipe fio the west is the original drainage pipe out of this catch basin and continues to the west along the north side of NE 4fh St. The primary drainage within the 12" pipe continues to the west along the norfh side of NE 4th St. because the original outlet pipe fo the west is at an elevation of 337.5 ft. The new outlet pipe to the south has an inverf elevation of 337.68' The downstream drainage pipe continues to the west along the norfh side , of NE 4th St., for 400 ft. past this catch basin. Here it enters another type 2 catch basin at the intersection with Monroe Ave. NE. This catch basin has ' an outlet pipe to the norfhwest and into a 60' section of pipe. This pipe '�, connects to a type 2 catch basin at the nortMwest corner of the Monroe I St. intersection. The 12" storm drain then continues west along the norfh �! � gutter line of NE 4th St. The above information was obtained from the as- built plans for the drainage improvements to NE 4th St. (plan file #R-1940). ' �., i ��,E.:;,r,a � PUGET.SOUNO�.J.s � �� s P�:..,,:. � ,�� i i,�,/ ��- ,.., N - -- -- - --___..1--- - . _\ .. _ _ . ---- ...--,- . ._----- - _._ .. .--- --_.. ...-- - ----- � -- --_.. � � � I:A�IIILII � • , w. 1'. W �UU�I � � W � _�p ^ i � � � - . .. 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I .•' m u� m �,- • ��• L I U Y� G �� , O Y.• 'o � �... � .+ ''• � > �' �* - � � y. �� .✓� �� a < � :�. {. r t t1';b �.s W - y I�'1 Irr � 4 �n V ; „ .'�% . - " _ .. .d�, - -- , I „' J`';- �� - _[ - � - ~• �% ��;{� '�Q � - - - - --�f " � Li� � �SI - .� - --- �- �'3P � A�� „ li �;� ---�Y '� �p \ � a N =z a .•� : • ` �^• � � � � �� U .T � "`-�� _ u I::�� -. .___-_ _-- � V � r , Y / x ' C � � � �" .' � �� f � v � a U ^ F cn � I �!� I U, o �w � a� � - . 4 �� , • __J�J . . E. °i � u r U O �� • (�� w. j '��. +.' , �I�.:-r�i � N ,'� .I_:•••_ • ;I' �! -- .l �a�Y � 1..j��-._� � S a ' - . i �� l�� ...N• , .. .t � � e �' - ' .yq ,.�._�s� .�.'.�____�� a ��/ �� u . , � . -� . � �., � �' � � , . ..—=- • � - �A `=r '°a'�• Am�' HeD . I � ' �� I - '� � . . . . .: '* . �'O _. � :'rt�`• ._ „ �/ . �I� , _ , �� ' •�'�''-_� .-.-.-. � �. ,�, — II. CORE DRAINAGE REQUIREMENTS 1. Discharge at Natural Location: The site currently discharges into an existing drainage system within the properfy or onto the adjacent property to the west. Both the onsite pipe and the adjacent property discharge into the existing drainage system within NE 4th St. The proposed drainage system will connect to the same catch basin within NE 41h St. as the existing onsite drainage system. As ! such, the location of the site's drainage discharge will not change. 2. Off-Site Analysis: i An upstream and downstream drainage analysis has been performed , and is detailed in section III of this report. � 3. Runoff Control: r This project is providing peak rate runoff control. A standard drainage detention performance will be used. The 1990 King County drainage manual will be used as the guideline. The detention pipe will provide the required detention volume. An orifice type restrictor will be used to meter the discharge from the pipe. The standard detention requires the developed site discharge to match the pre-developed peak flows for the 2 year, 10 year and 100 year storm events and adding a 30% volume factor to the calculated detention volume. 4. Conveyance System: The project will provide conveyance piping for the site drainage and the building roof downspouts. The piping will be sized to handle the 100 year developed storm event. 5. Erosion and Sedimentation Control Plan: An erosion control plan will be prepared and will be included with the engineering plans. This erosion control system will include silt fencing along the west and south properfy lines, construction entrance, seeding 8� mulching and clearing limits. Grading for this project will be minimal and clearing is negligible. Sediment storage is not proposed. 6. Maintenance and Operation: The improvements to this site will remain private. The drainage system and pavement will be maintained by the property owner's staff or management company. 7. Bonds and Liability: The appropriate bonding and insurance forms will be secured prior to any construction on the site. IV. DETENTION ANALYSIS AND DESIGN A. PREDEVELOPED DRAINAGE The existing drainage is collected by the existing drainage system or sheet flows to the west/southwest and onto the neighboring property. The existing drainage system consists of a network of 24" diameter detention pipes and type 2 catch basins. There is an existing flow restrictor on the existing catch basin near the southwest corner. This catch basin discharges into the existing 12" storm system within NE 41h St. The drainage system collects the runoff primarily from the constructed gravel parking area within the east/center of the site. The perimeter vegetated areas sheet flow to the west and south. There is also an existing drainoge system within Olympia Ave. NE. This system collects the runoff from the existing road pavement. The area used for the pre-developed calculations is the total property orea plus that half ROW portion of Olympia Ave. NE that will drain to the west. This street frontage along Olympia Ave. is c�rrently existing asphalt and will modeled as impervious in the pre-developed conditions. The frontage along NE 4m St. is fully improved and will not be included in the drainage area. It does not drain into the site's drainage system. The area calculations are shown on the following worksheet. The soils on the site 'I are Alderwood series, which is a hydrologic group "C" type soil for the ' drainage calculations. The project area used for the calculations is 0.92 , acres. This is the total site area plus 20' of the Olympia Ave. frontage. The existing compacted gravel parking area was considered as impervious surface. This is allowed because there is an existing constructed drainage system within the parcel that was designed to drain an impervious parking lot. This is shown on the approved drainage plans and confirmed by the existing site as-built p(ans. The existing drainage analysis was performed using King County's SBUH hydrograph method. Its summary tables and charts are attached for reference. The methods outlined in the 1990 King County Surface Water Design Manual were used as guidelines. Following this page are the dato sheets used for the computer input data. The computer summary sheets for peak flow and storm events are also attached. Below is a brief description of the pre-developed drainage characteristics: project area: 0.9278 acres exist. impervious orea: 0.47 acres, weighted CN=91.7 (gravel 8� asphalt) exist. pervious area: 0.45 acres, CN=85 (grass/dirt) 2 year peak flow: 0.18 CFS 10 year peak flow: 0.33 CFS 100 year peak flow: 0.51 CFS I �I�� ---------- _�- ��t �-m 11'� '�a�S s a�c,U�W �y�• � � _ �� -------- T�' G�11 ----- -- Q�g � j ' � �-S.� � _ .-�,� _�� _ ----- � �, � � �� _ `,,�, ---- ----_ _ I, � -� � � �� / — — --- -- /�`�� S'-s°-�"� `'"'°�' �� '� ►O 1� ,��S\� � ��_ �,..,� -- - -- �;�a -,- Ncrj �O �v��.�.. � � �� - �� Q�� I � ��- s�� s�s� � _ - - - C'� `� ) sa� raS ��jl - �. -ac�� s�� C� � �� '�� ss�� s �i �a� a�,ts ��v,�^av�na� •� `� S i� ' � _ L�' '� - 2�' � �,S c�o�n.�-�� n �� ; .Sc�o� n�-a� �v,tLS� �r9 r \ \ . �� , � L J b = �,� ,o�� .o � ,� ��.o � ., .� , �.� .� ��1' O = � �'z� ; ' � �.�w�j.�Q �v� - � _ ��t �Gb ' O � S 6 = � �.S' oS 1 ;�r�� U�� f�v�n-� ��,�}sv,� � 2 - -�► �� ' � � a�, ��od b� - r�'J� _ �.. � � .� �� - , � �S � -� � , �� r�-� gu�-s� � _ . ; Sno,T�..nn � -��n _ � `-�s''� _ c'� - _ � <c o�� :, _ --- �'� I �U �8 �� I W'� U - "-�S w�n 8D � '"�.� s U-,�. 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Jaeger Engineering - URBAN CR.AFT MIXED USE DR.AINAGE CALCS PRE DEVELOPED HYDROGR.APH SUMMARIES BASIN SUNII�IARY BASIN ID: A10 NAME: PREDEVELOPED, 10 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .92 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 .45 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 85 . 00 TIME OF CONC. . . . . : 13 . 95 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 0 .47 Acres CN. . . . . 91 . 70 PEAK RATE: 0 .33 cfs VOL: 0 . 14 Ac-ft TIME: 480 min BASIN ID: A100 NAME: PREDEVELOPED, 100 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 92 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 .45 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 TIME OF CONC. . . . . : 13 . 95 min IMPERVIOUS AREA ABSTR.ACTION COEFF: 0 .20 AREA. . : 0 .47 Acres CN. . . . . 91 . 70 PEAK R.ATE: 0 .51 cfs VOL: 0 . 21 Ac-ft TIME: 480 min BASIN ID: A2 NAME: PREDEVELOPED, 2 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 92 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 45 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 TIME OF CONC. . . . . : 13 . 95 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 0 . 47 Acres CN. . . . . 91 . 70 PEAK RATE: 0 . 18 cfs VOL: 0 . 08 Ac-ft TIME : 480 min V • File Basin Hydrograph Storage Discharge Level pool 3eee5eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee2eeeeeee2eeeeeeee;eeeeeeeeee; 0 o SHEET FLOW CALCULATOR - INITIAL 300 FEET ° o 0 0 0 0 °DES°Mannings Sheet Flow. . . . . : 0 . 1500 ° ° °ARE°Flow Length (ft) . . . . . . . . : 110 . 00 °HOICES ° �RAI°2 yr 24 hr rainfall (in) : 2 . 0� ° ° °TIM°Land Slope (ft/ft) . . . . . . . 0 . 0180 ° ° °TIM° COMPUTED TRAVEL TIME (min) : 13 . 95 ° o °R.AI° TYPICAL MANNINGS VALUES FOR INITIAL 300 FT °A ° o�S o 0 0 °BAS°Smooth Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 011 ° ° °STO°Fallow Fields of Loose Soil Surface. . . . . . . . . . . . . . . 0 . 05 °Y ° ° °Cultivated Soil with residue cover (s<=0 .2 ft/ft) : 0 . 06 ° ° °PER°Cultivated Soil with residue cover (s>0 . 2 ft/ft) . : 0 . 17 ° ° °ARE°Short prairie grass and lawns . . . . . . . . . . . . . . . . . . . . . 0 . 15 ° ° °CN °Dense grasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 24 ° ° 0 oBermuda grass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 .41 � o 0 oRange (natural) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 13 � o °PEA°Woods or forest with light underbrush. . . . . . . . . . . . : 0 .40 ° ° °PEA°Woods or forest with dense underbrush. . . . . . . . . . . . : 0 . 80 ° ° °TOTo 0 0 ° OF10Key: QUIT F5Key: CLEAR °ete ° ° Pgaeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeefit ° aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee �I�C ��i�.C��✓�LJ 1 L T�,� �F C� t� C��.f��t�� . B. DEVELOPED DRAINAGE Similar to the pre-developed project, the developed project will include a total project area of 0.92 ocres. The developed drainage calculations used fihe actual calculated impervious surfaces based on the site plan. The building area was calculated as 0.30 acres (building footprint) and the parking area/driveways/walkways were calculated at 0.41 acres. The parking under the second floor of the building was considered as building since any drains in this area will be connected to the sonitary sewer. The impervious surface within the half ROW along Olympia Ave. NE that drains to the site is 0.14 acres. The total impervious surface was 0.85 acres. The detention facility will be a detention pipe along the west and south property lines. The existing 24" detention pipe will be removed. The detention pipe will include o 6" freeboard depth obove the live storage depth within the 60" diameter pipe and a 6" sediment storage depth below the outlet invert. Similar to the existing condition, the King County SBUH method was used to determine the peak flows for the developed site and the level pool analysis. The time of concentration was assigned a value of 5 min�tes. This a commonly accepted minim�m time of concentration for small densely developed sites. The computer input data sheets for the developed flows and respective sfiorm events follow this page as well as the impervious area works sheets. A brief summary of the developed drainage characteristics are: Project area: 0.92 acres Impervious surface: 0.85 acres, CN=98 Pervio�s surface: 0.07 acres, CN=86 (landscaping) 2 year peak flow: 0.36 CFS 10 year peak flow: 0.53 CFS 100 year peak flow: 0.73 CFS f � �.cr=.�c_o� D�rt�► �-�� Gon.�� no r.� _ ____- --- _ _------ — I - {�+R� : . - - -- �S� �t-�e sc�-w�- '��--� �i_� ca.v-� - ------- _ _0.S_ � GL��X _ tr' 't"Y14: �{--e-—��.2.�f P�(,� --- _ __ �� v� - = 33��a a o f c��o - �nf� _ i�-re�- = 0, �'Z I�� -- ___ _ _ - - 2 C.�R�(� t�.0 vY1 ��2: �� _ _ -----_ .p �` _ _ do �e-t'`�es dL..�_ S� �� T�l � �� ---- _ �J _ �� G G�� C _-_______ - -- ------- �) �rn�-+��!o vs 5�r��: C� = 9�8 --- -- --- _ ( . 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URBAN CRAFT MIXED USE DRAINAGE CALCS DEVELOPED HYDROGRAPH SUNA4ARIES BASIN SUMMARY BASIN ID: B10 NAME: DEVELOPED, 10 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 92 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 07 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 5 . 00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 0 . 85 Acres CN. . . . . 98 . 00 PEAK R.ATE: 0 . 53 cfs VOL: 0 . 20 Ac-ft TIME: 480 min BASIN ID: B100 NAME: DEVELOPED, 100 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 92 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 07 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 5 . 00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 0 . 85 Acres CN. . . . . 98 . 00 PEAK R.ATE : 0 . 73 cfs �'OL: 0 . 27 Ac-ft TIME : 480 min BASIN ID: B2 NAME: DEVELOPED, 2 YEAR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 92 Acres BASEFLOWS : 0 . 00 cfs R.AINFALL TYPE . . . . : TYPElA PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 07 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 ' TIME OF CONC. . . . . : 5 . 00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 0 . 85 Acres CN. . . . . 98 . 00 PEAK RATE : 0 . 36 cfs VOL: 0 . 13 Ac-ft TIME: 480 min �i ��CJ �%�vi iv�.... :..�iy �.i � y�:� ..��c_, _ � � . .. "�,,..,. . _ � - . , ..i�l ��.i' � ,��..� i �� ..,1 � t'�i �...._, - ;J r.. :� . for this site. This requires that the developed condition peak flow� year, 10 year and 100 year events not exceed the respective pre developed peak rate� . _:_��:�__ �� . .� -;.,�, „�. �_ ,_ ��1�� _ �� , final detention volumE The detention pipe was designed using the SBUH hydrogroph me� _ : the Watervvorks hydrology program. The level pool analysis showed that the required detention volume for the 100 year storm event is 1356 CF. This is increased by 30% for a required storage volume of 1763 CF. See the attached level pool analysis summary. D. DETENTION ANALYSIS AND DESIGN The minimum design volume for the detention pipe was determined by the Waterworks level pool anolysis. The following was used to design the detention pipe shown on the plans. • Detention volume required: 1763 CF • Vol�me provided in 200 LF of 60" diameter pipe, using or�!y the 2' of depth above the centerline of the pipe: 17b0 CF • Additionally, storage within the 3 type 2 catch basins ccn be courted towards the storage volume: • Vo(ume within 3 type 2 cotch basins (48" dia, 2' depth): 75.4 CF • Tota! volume provided: i 835.4 CF . Jaeger Engineering URBAN CR.AFT MIXED USE DRAINAGE CALCS LEVEL POOL ROUTING ANALYSIS LEVEL POOL TABLE SUNlN1ARY MATCH INFLOW ST DI <-PEAK-> STORAGE <--------DESCRIPTION---------> (cfs) (Cfs) id id <-STAGE> id VOL (cf) --------------------------- --- 2 YEAR . . . . . . . . . . . . . . . . . . . . . . . 0 . 18 0 . 36 1 1 341 . 26 11 652 .47 10 YEAR . . . . . . . . . . . . . . . . . . . . . . 0 .33 0 . 53 1 1 341 . 78 12 1 100 YEAR . . . . . . . . . . . . . . . . . . . . . 0 .51 0 . 73 1 1 342 . 39 13 1355 . 98 � �( , R�,�'�a File Basin Hydrograph Storage Discharge Level pool Jaeger Engineering 2eeeeeeeeeeeeeeeee ; 3eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee2eeeeeeeeeeeeeeeeeeeeeeeee ; ° ROUTING COMPARISON TABLE ° ° I�^.ATCH INFLOW STO DIS PEAK PEAK OUT ° ° DESCRIPTION PEAK PEAK No. No. STG OUT HY"D ° �---------------------------------------------------------------------- � ---------------------------------------------------------------------- °2 YEAR 0 . 18 0 . 36 1 1 341 . 26 0 . 18 11 ° °10 YEAR 0 . 33 0 . 53 1 1 341 . 78 0 . 33 12 ° °100 YEAR 0 . 51 0 . 73 1 1 342 . 39 0 . 51 13 ° 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ° ______====>Done<===-__------ F10 to Exit ° aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee� �vailable Memory remaining: 183576 bytes Current Data Set Name : \urbancft .bsn ��V�(� ��(� ��LtS�� S v t�'� � f � File Basin Hydrograph Storage Discharge Level pool J2eeeeeeeeeeeeeeeeeeeeee; 0 0 °Rectangular vault ° °Trapezoidal basin ° °Underground pipe ° °Sto list ° °Custom file ° 3eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee; ° CUSTOM STG-STO LIST ° ° STORAGE STRUCTURE ID: 1 ° °NAME: UPPER HALF 60 PIPE ° °INCREMENT: 0 . 10 ° 0 0 ° STAGE STORAGE STAGE STORAGE ° °l : 340 .40 0 . 00 6 : 0 . 00 0 . 00 ° °2 : 340 . 90 384 .40 7 : 0 . 00 0 . 00 ° '�� °3 : 341 .40 753 . 30 8 : 0 . 00 0 . 00 ° j °4 : 341 . 90 1088 . 10 9 : 0 . 00 0 . 00 ° �� °5 : 342 . 40 1364 . 00 10 : 0 . 00 0 . �0 ° 0 0 °PGUP PGDN F3 : Get F6 : Delete F10 : Exit ° aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeF �= - _ ' _= -_ _ _ Available Memory remaining: 204008 �----� Current Data Set Name : \URBCR.AFT.bsr. �✓✓ � j J�,� _.� - ��p�GF �U C-��R� `' 3 �� ►ss r� c�v s�;-oNn 5�.�- - S-b�c.� 1 i s-� S�IOw �v1 �5� �,irn . ��. o� L°C� �� ` �� de 'tn �.bo�� Q �.�e- i l�S�n� T ne- 2 � � � ` r �� ,,�,-t-.e,� �� -�n� P,� v�n�Y � s� �I�nne.Lc�� G�r�n. 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P�PF i o�'o-� c-t�,;s- Sec�►cv�.� O�.r�o�.- � I 4,b 3 S� — _ - __ - - _ _ __ _ _ _ __ - - - -_ � — - - -- -_ ___- - -- --- --- - ---- - �;� � File Basin Hydrograph Storage Discharge Level pool 3eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; � MULTIPLE ORIFICE ° � DISCHARGE STRUCTURE ID: 1 ° 0 0 °Name: FLOW RESTRICTOR ° °Peak Dsgn Release Rate: 0 .51 cfs Orif /flow/elev ° °Orifice Coefficient . . . : 0 . 62 Dia (in) /cfs/ ft ° °Lowest Orifice Dia (in) . . : 2 . 67 ° °hl : Outlet to 2nd Orifice: 0 . 90 341 .30 ft ° °Second Orifice Dia (in) . . : 2 .37 ° °h2 : 2nd to 3rd Orifice. . . : 0 .50 341 . 80 ft ° °Third Orifice Dia (in) . . : 2 .00 ° °h3 : 3rd to 4th Orifice . . . : 0 . 00 ° °Fourth Orifice Dia (in) . . : 0 . 00 ° °h4 : 4th to Sth Orifice. . . . 0 .00 ° °Top Orifice Dia (in) . . : 0 . 00 ° 0 0 °Elevation of Lowest Orifice. . . . : 338 .40 ° � °Outlet Elevation. . . . . . . . . . . . . . . . 340 .40 ° I °Max Elev Above Outlet . . . . . . . . . . . 347 .40 ° ', °Stage-Disch Increment . . . . . . . . . . . 0 . 10 ° 0 0 Av°PGUP PGDN F3 : Get F6 : Delete F10 : Exit ° Cuaeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee� �(,t�.�.� 'R��"�R� �=� t2 S�� - -- -- -- ------- -- '�� DO� = a ' _ !I 1 s c�o-� �- �� -_'�� a� - 2�i�-- �,c��—c�. -j u�,�i rn � ,C -�.,� ,, � " �� , ' J ' , S i �a�o �� _:.a� • v, u� � So � so� _ Ip �p s SQ : _ ,L ; � _ —��-��ZT ,; - �:.-L� oV��^J� � � � �;i U �`� Z S �J Z � _ �S � I��+ W�1 ro � ,�.. �.� 1 \ - -- _ _ �� =� .S�Tj1�� Q - � �X� `a"��0.� rL� ,,,�1 b� - .j.� cJ Y � O .� .�J O�� ( = �' $ OC�L `� ` !v�27 mG' � ,Z , C�oZ � >>� o.� �1 Q ! �C �� _ �'� G o' O - `1 `l�"J� S 's oUJ, � n � ;i � � ; � , , � .asn � , ,, � l� � a�' � � � �1 a�- o � ° •z ' , 9 � ,� O -�- o V�� 'a vv� � � ; vY-o �.'a � n !; � -` -- - � ' r I i � � � ; i.� �'� ' A Jaeger Engineering URBAN CR.AFT DR.AINAGE CALCULATIONS WATER QUALITY STORM HYDROGR.APH SUNIlKARY BASIN SUMMARY BASIN ID: C2 NAME: WATER QUALITY STORM, 6 MOS . SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 78 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERVIOUS AREA PRECIPITATION. . . . : 0 .67 inches AREA. . : 0 . 07 Acres TIME INTERVAL. . . . . 10. 00 min CN. . . . . 86 . 00 TIME OF CONC. . . . . : 5 . 00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 .20 AREA. . : 0 . 71 Acres N. . . . . 98 . 00 PEAK RATE: 0 . 08 cfs VOL: 0 . 03 Ac-ft TIME: 480 min u �,�., S��n �a� � U�c��- Qvc� �'�( �-o�, v �l�t� = o ,v3 �� -�- = t 3o c� •� �. x VI. CONVEYANCE SYSTEM � The piping was sized to occommodate the 100 year developed flows as identified in this section of the report. The modified rational method was used as shown in the King Co�nty Droinoge Mc,nual. The pipes for this development are a minimum 12" diameter and all have a minimum slope of 0.50%. The 100 year storm flow for the entire developed site was calculated to be 2.24 CFS. The capacity of a 12" CPEP pipe at a 0.50% slope is 2.73 CFS. Thus, the minimum pipe segment within the developed drainage system can handle the entire site's 100 year peak flow. _._____ ____ _ _ _____ _ _ _ _ !; ___ --- - ---- __----- -- _- ---___ -�T�� ----- _ ( � ', — - E - _ � f� _— � �. a � � '' - - �a u w� _� j I __ `�u 1 _wa -- �� , Cl � � S � �: � _ _ i i S�� ►Wd S VV`c'1 1 Vi 1 V,jt � -- i � L' Z = �a�'S '� ,� �� ,�Z :�o `�' �'' -- -��"J fiZ' Z _ '�I '� o�' Q �L'O = �1s aati.�.v�d iI'� -- �—'J__—, �: i� I '� _ �� -- � �� ?' z � ' � _ .1, ' -- , � - :.! � L �j �� - � �`� -- 1 � �' ' � i��z = .a = �, I;; z � _ �; : �° �'t's'�v '� i►.�5 _ ►i �� = ,,�--o��.� � �� v� �-�- I !1 � - ; � -sa_,j,� `�u , _ O L� lKa-j 1. 'a ,,,., �.M n V.��V�� ! �C�' �i � C�b' O ='� ; s�O1 h w�l 1t-�o ls v�o� !�Z ,� �, �� s a..,r� gL' p = a.�,' S c i( ;� �� — � ,S NQ ��-�_-� ' j k I',' ( � � I' • r,� ' � � ^ Circular Channel Analysis & Design Solved with Manning' s Equation Open Channel - Uniform flow Worksheet Name : Comment : Solve For Full Flow Capacity Given Input Data: Diameter. . . . . . . . . . 1 . 00 ft �� Slope. . . . . . . . . . . . . 0 . 0050 ft/ft ', Manning' s n. . . . . . . 0 . 012 Discharge. . . . . . . . . 2 . 73 cfs � Computed Results : ' Full Flow Capacity. . . . . 2 . 73 cfs ' Full Flow Depth. . . . . . . . 1 . 00 ft Velocity. . . . . . . . . . 3 .47 fps Flow Area. . . . . . . . . 0 . 79 sf Critical Depth. . . . 0 . 71 ft Critical Slope. . . . 0 . 0069 ft/ft , Percent Full . . . . . . 100 . 00 0 Full Capacity. . . . . 2 . 73 cfs ' QMAX @. 94D. . . . . . . . 2 . 94 cfs , rroude Number. . . . . rL'LL C�SP�L 1rt`{ ��- Iz �� -�� S% � Open Channel Flcw Iscdule, �'ersion 3 . 12 (c) 19op '� Haestad Methods, Inc. * 37 Brookside Rd * ��aterbury, Ct 06708 � � �.: � R.4770\.q].'�SE�}iOD r TABLE 3?1_� FU'�'OFF COEFFICIEITS-"C'\'ALLES FOR THE RATIO\.4L'�SETHOD General Land Covers Single FamilyAesidential Areas� Land Cover C Land Cover Density C Dense iorest 0.10 0.20 DUIGA(1 unii per 5 ac.) 0.17 . Light torest 0.15 0.40 DUiGA(1 unit per 2.5 ac.) 0.20 Pasture o.20 0.80 DU/GA (1 unit per 1.25 ac.) 0.27 Lawns 0.25 1.00 DU!GA 0.30 Playgrounds 0.30 1.50 DU/GA 0.33 Gravel areas 0.8� 2.00 DU!GA 0.36 Pavement and roois 0.90 2.50 DU.�GA 0.�9 Open water(pond, 1.40 3.00 DU!GA 0.42 lakes, wetiands) 3.50 DU.'GA 0.45 4.00 DU.�GA 0.48 4.�0 DU.�GA 0.51 5.00 DU.'GA 0.54 5.�0 DU,'GA 0.57 fi.00 DU,'GA 0.60 � Based on average 2,SD0 souare ieet per lot cf impervio�s coveraoe. For com5in�;i�ns of land covers lis'ed abcve, an �rEd-�':eigh,ed"C�:x.4," s�� shouid be cor-;��ted based on ihe ECUdt1011 C�: X A�_ �Ci X,4i� + �C�X.��i ...+�C,X A,�, �ti'�lEre A;_ (A, +.;� + ...+,�,,�, the tot21 craia2ce basin cfEd. 1 TABLE 3.2.i.B COEFFICIE?iTS FOR THE R,�T10�.aL �tETHOD��,�•�� EQL'.aT1o� � Design Storm Return Frequency I c� I b� � 2 ��e�rs i.5g �.=g ' 5 ��e�rs 2.33 0.53 10 ye2rs 2.=� �.64 25 years 2.66 0.6� 50 vears 2.7� 0.55 �00 years 2.51 Q.63 TAI3LE 3.2.1.0 kR�'ALL�ES FOR T,CSI1G THE RATIO\AL 11ETNOD ' Land Cover Category I �R rcrest�vith heavy orcund f;;;er and me�de��v 2.5 Fallo�v or rninimum:iilaoe cu't;vation 4.7 ' Short grass pzs?ure and lav,�rs 7.0 I Neariy C2re grourd 10.1 Gfc55E�15'2;ER�12y iS.O Paved area (sheet`Ic��✓) �rd shallo��r outter flc�� 20.0 I99S S�rface\'�'a;er Desi�n'�9�r.L�] �i rog 9..,, , 3-13 r VII. ERUSION CONTROL SYSTEM The erosion control system was designed to eliminate any onsite runoff from entering the adjacent properties or right-of-way. In order to accomplish this, a interceptor silt fencing will be constructed along a portion south and west property lines. This site is small enough that a sediment trap is not required. This site has afready been cleared and graded. The existing site is approximately half covered with gravel, being used as an overflow parking area. Additionally, silt fencing will installed along a portion of the east property line as well as the south and west properfy lines. These are the downgradient properfy lines and is the most sensitive regarding neighboring lots and right-of-way. The proposed grading for this plat is well-defined and limited to the northeast corner of the site. The area disturbed will be minimized. The existing vegetation will be left on the ground as much as possible during the site work. The eroslon control plans also show the clearing limits and the locations for rock pad construction access points. There are no trees on the site so a tree plan is not necessary.