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Home My WebLink AboutSWP272077 Short Plat (SHPL# ) REQUEST FOR PROJECT # Prclim. Plat (PP# ) To: Technical Services Date WO# Z Green# From: Plan Review/Project Manager . K Project Name c AI✓'C r1- (70 characters max) Description of Project: Circle Size of Waterline: 8" 10" 12" Circle One: New or Extension Circle Size of Sewerline: 8" 10" 12" Circle One: New or Extension Circle Size of Stormline: 8" 10" 12" 14" Circle One: New or Extension Address or Street Name(s) iA tv) A l/e, , h(o Developer/Contractor/Owner: Wlc t-�"v(A -TI4om (70 characters max) Check eac h discipline involved in Protect Ltr Drwg # of sheets per discipline O Trans-Storm "C V-T H (Ic j u) (Roadway/Drainage) (Off site irnl"vem m entsxinclude basin name) (include TESC sheets) ❑ Transportation (Signalization,Channelization,Lighting) O Wastewater (sanitary sewer Main)(include basin name) — — ❑ Water (Mains,valves,Hydrants) (Include composite&Horizontal Ctri sheets) TS Use Only 'L) --2,0 7 % s alp - 14 Approved by TSM Date: for m/miscl92-090.DOC/CD/bh CITY OF RENTON PLANNING/BUILDING/PUBLIC WORKS MEMORANDUM DATE: January 9, 1996 TO: Niel Watts FROM: Ron Straka Staff Contact: Mike Dotson SUBJECT: Request for information concerning Thompson 4-Plex Storm System Construction We have been requested by Mr. John Hanson, an attorney representing the owner of the subject 4- Plex, to provide information concerning the construction of the drainage system for the complex. The 4-Plex, located at 3101 NE 13th Street, was covered by permit # P-8141, W.O. 87312 and SA-037-91 (see attached). Apparently, the on-site storm system for the subject 4-plex has had problems with back flows from the city system during intense rainfall events. Maintenance crews have reported that some ponding and overland flows have occurred at the 4-plex and neighboring properties. Some damage has been reported as a result of this flooding. We assume that the attorney has been asked to collect information in regard to the owners defense of damages and/or litigation against the contractor and engineer who installed the system. We have been unable to locate any as-built or construction drawings for this project. Our records include a TIR for the project and a signed off construction permit. Since your inspectors and plan reviewers probably have the most information concerning this project, it would probably be best to have you as the contact person for this request. For your information, Ron Shaffer of our maintenance division has corresponded with Mr. Hanson. He has stated that, to his knowledge, the system was constructed "per plan". Would you please contact Mr. John Hanson, Attorney, at 206-833-2044. He would like to be contacted as soon as possible to prepare for a court date next week. If you have any questions please call Mike Dotson at X-6192. Thank you. cc Ron Shaffer WATTS.DOC/MD PLANNING/ BUILDING/ PUBLIC WORKS DEPARTMENT ��`�Y O MUNICIPAL BUILDING 200 MILL AVE_ SO. RENTON, WASH. 98055 UTILITY SYSTEMS DIVISION - 235-2631 N� TRANSPORTATION SYSTEMS DIVISION - 235-2620 TO: DATE: 1 9 JOB NO. : 3,9 RE: ATTN: GENTLEMEN: WE ARE SENDING YOU ATTACHED ❑ UNDER SEPARATE COVER VIA THE FOLLOWING ITEMS: ❑ SHOP DRAWINGS ❑ PRINTS o REPRODUCIBLE PLANS o SPECIFICATIONS o COPY OF LETTER o COPIES DATE NUMBER DESCRIPTION AND REMARKS 1 � � THESE ARE TRANSMITTED AS CHECKED BELOW: ❑ FOR APPROVAL o APPROVED AS SUBMITTED ❑ RESUBMIT COPIES FOR APPROVAL o FOR YOUR USE a APPROVED AS NOTED a SUBMIT COPIES FOR DISTRIBUTION AS REQUESTED ❑ RETURNED FOR CORRECTIONS a RETURN CORRECTED PRINTS ❑ FOR REVIEW AND COMMENT ❑ ❑ PRINTS RETURNED AFTER LOAN TO US COPIES T0: SIGNED TITLE — IF ENCLOSURES ARE NOT AS NOTED, KINDLY NOTIFY US AT ONCE PUBLIC WORKS DEPARTMENrrY OF RE-N. ENGINEERING DIVISIONl CITY OF RENTON, WASHINGT,pp APPLICATION ONLY — UNTILBIdA�LJDATE` a' PERMIT - NUMBER Owner Location of Work Wr.,t..pow �. -�. oM P�noJ Address �`--Tf eT �Si✓ �� -1 2- •K f P K t_A 0 r? AVM 14kf? ► 3,7k Zr. INSPECTIONS FEES '�i.� r e r Ce►�ys cY'� CONSTRUCTION Sanitary Sewer/Storm Water Permits ('00. cv Right-of-Way Construction 2C�, 00 AT PERMIT Right-of-Way Inspection Fees vc> C -.,:-� (Public Right-of-way) Water Inspection/Approval Fee Special Utility Connection Fee, Water 2.1 f5o, Oe-�? Water Latecomer Fee - - Special Assessment District, Water vr�y VG--rl 0,4 - Date Issued Sewer Inspection/Approval Fees )LA -q j Special Utility Connection Fee, Sewer I. b Expiration Date Sewer Latecomer Fee - y - `� Special Assessment District, Sewer y Reference Data Special Deposit, Private Latecomer Deposit, Cash AW TOTAL FEE Description of Work and Number of Feet "-5�—Irwrr .esltUt2m MPrtiaj(j , WA•TC%'7 Ati(2 e MP1�G�Vc�N(r�JT� YC12 APMC,4612 YL-AtAe1 DATC Contractor Business ^7 >��TRL IC., License {�3t#- address Bond Telephone o rJ TA 6-T : CA(Z t_ PId 12 p -, 6 PV-OJ 6 T Win;�'(• 17'2 5 -•. c v,Z IT IS UNDERSTOOD THAT THE CITY OF RENTON SHALL BE HELD HARMLESS OF ANY AND ALL LIABILITY, DAMAGE OR INJURY ARISING FROM THE PERFORMANCE OF SAID WORK. ANY WORK PERFORMED WITHIN THE RIGHT-OF-WAY OR ON SEWER MAIN MUST BE DONE BY A LICENSED, BONDED CONTRACTOR. LOCATE UTILITIES BEFORE EXCAVATING. .L 235-2631 FOR INSPECTION. -1 between 8 AM and 9 AM for APPLICANT ;pection in afternoon; call 'ore 12 Noon the day before inspection in morning. PUBLIC WORKS DIRECTOR :CIFY TIME FOR INSPECTION. j .L ?35-2620 for street signs CALL BEFORE YOU DIG By 1 ghting. 48-HOUR LOCATORS - -- 1-800-4?4-g5r,u 1 1 1 1 KIRKLAND AVENUE 4-PLEX 1 SA-037-91 1 STORM DRAINAGE 1 TECHNICAL INFORMATION REPORT 1 DATE: 11/5/92 1 1 st REVISION BY. 1 RESCO INC. JEFF HERB 1 FOR: CITY OF RENTON 1 PUBLIC WORKS DEPARTMENT 6 CIVIL AND MECHANICAL ENGINEERING �P 17815 S.E. 146TH ST., RENTON WA. 98 5 1 PH.(206) 228-4244, FAX (206) 228429 01 CrTY Of r*NTUN 1 .E C E I V E x V V 0 9 1992 1 r 1 � ' ---TABLE OF' CONTENTS ------------------------------ SECTION I ' OVERVIEW OVERVIEW _ I . 1 VICINITY MAP I .2 TIR WORK SHEET I .3-4 REPORT CHECK LIST I .5 PRELIMINARY CONDITION SUMMARY SOIL MAP II . 1 USGS MAP II .2 25 YR 24 HR ISOPUVIAL CHART II .3 100 YR 24 HR ISOPUVIAL CHART II .4 TIR SECTION III OFFSITE ANALYSIS CORE REG. 1 DOWNSTREAM ANALYSIS III . 1 CORE REG. 2 DISCHARGE LOCATION III .2 TIR SECTION IV ' DETENTION ANALYSIS (CORE REG. #3) GENERAL REQUIREMENTS IV. 1 ' PREDEVELOPED BASIN MAP IV.2 POSTDEVELOPED BASIN MAP IV.3 PREDEVELOPED BASIN HYDROGRAPH IV.4 ' POSTDEVELOPED BASIN HYDROGRAPH IV.5 CN CHART IV.6 2-YEAR ISOPLUVIAL CHART IV.7 TIR SECTION V CONVEYANCE (CORE REG. #4) iCONVEYANCE SYSTEM ANALYSIS V. 1 BIOFILTRATION V. 1 TRIBUTARY BASIN MAP V.2 CONVEYANCE SYSTEM CHART V.3 RATIONAL 'C' CHART V.4 WEIGHTED C CALCULATION V.5 TIME OF CONCENTRATION V.5B 25 YEAR STORM INTENSITY V.6 100 YEAR STORM INTENSITY V.7 PIPE SIZING 25 YR. (MANNING) V.8 PIPE SIZING 100 YR. (MANNING) V.9 SECTION IX ' EROSION SEDIMENTION CONTROL DESIGN (CORE REG. 5) GENERAL REQUIREMENTS IX. 1 1 1 1 . 1 ! TIR SECTION 1 PROJECT OVERVIEW ! i ! 1 ! ! ! ! ! 1 i THOMPSON 4—PLEX STORM WATER CALCULATIONS ' TIR SECTION I PROJECT OVERVIEW ' INTRODUCTION: The proposed four-plex is located along the South side of N.E., ' 13th Street directly East of an existing duplex, 1222/1224 --• - Kirkland Ave NE in Renton, Washington. The site is contained within the North Renton drainage basin(See Vicinity Map. ) Access ' to the proposed four-plex will be provided by a proposed driveway from N.E. 13th Street. This proposed driveway and parking area will be shared with the existing duplex to the West and is located within an access easement. ' EXISTING SITE CONDITIONS: ' The project site is comprised of 7200 sf of virtually flat, well maintained grass area. The Westerly property line is Bounded by a two to four foot rockery wall located on the property directly ' to the East. The site is not located in or near any land slide, erosion, seismic, or flood plain hazardous areas. STORM WATER SYSTEM: Since this project will create less than 5,000 sf of new impervious surfaces (4,980 sf to be exact) it is exempt from ' providing means of retention/detention. On-site Storm water generated within the proposed roof and parking areas will exit the site by means of a catch basin and a 12" CMP pipe. This pipe will tie into an existing 12" concrete storm drainage sewer below N.E. 13th Street. ' Biofiltration: ' Since the total increase in area subject to vehicle use is less than 5,000 sf this project is exempt from providing a means of biofiltration as outlined in core requirement #3 K.C. Surface Water Design Manual 1990. METHODS OF ANALYSIS: The 1990 King County Guidelines for Storm Drainage was the source used to design the storm drainage system. ' 1. 1 —IV M MUN I I:KtT Z = Z rr7 Fr ABERDEEN I r AV NE ABERDEEN m AV HE J m AV N �2 p Z Z :::•::,�::: - Z -�� BLAINE AV NE v M m co z Z x BLAINE C.I AV 'tiro,?y -� ti : m m rn CWAS mAV NE N mO NE ;2, NE CAMAS W NE i CAMAS AV 't'n�, DAYTON Z z AV NE ^' V o DAYTON AV m DAYTON N AV NE NE'• r' �EEDMONDS -� = x AV art' m S m NE FERI I)AIE �� a2� �, �" � T . Z FERNDALE R rE NHS GLENNW000 vxi .: " rr, -� m AV1�E 2 GLENNw0 o HARRINGTON m % ` ` 4 qV HARRINGTON � o to cn T AV E 2 ti TON r AV I NE m q9q�:;:•:.::,C�� -' NE INDEX Banc y tiF '1'Cr�:�'-•n ,r 2 Z a yF -�tn .•. Z y� ti Fr tiF JEFFERSON ` � Z AV NE N ��EAVERSIOE i3s1d�{�Ot� m EFFERSO AV NE x KIRKLAND AV ...: ♦ Z ��Z Z 7�. tP i m m ^ A 122ND AV _ �j x �� _ 'y `cC92o � .; ` LYNNWCOD AV NE Ty AV NE rn m m I �O `�N m .,�[ Z 2 MONI AV NE AA S r NEWPORT N •1^ _ = T N O AVN =m -i-� d H14Z` 4 a m S n N co OLYMPIA I AV"'"' m NE = D O I_" �` --a yiSZ� rn m 'o- r m y PIERCE 'iAV NIE m ' 0 r ram' PIERCE 0O 0 rn m __ "' 3 D _ S PL NE z 3S H19zt '•_ `fJ� N E AEN �^ AV NE cn � _:::-� � p 2 = f7 cn NE 128TH AV m m m SE I m REDMOND AV 'i _ - e 1n r N E ►V m ZA Z no Z � ' T 00 T' :4i �'"m _ -+ 12 TH V q z N0113HS SeSF 0 ' o IE __, rod T _ NF)� I CD J I 130TH AV SE SHELTON AV NE o ov I I e.h2' cn0 I com �,m AV ": ,NE� �� /UNION AV ` T NE _ 132NDIAVI S N� 2F �?�'r VASHONIm I W/(�3� VASHON Z2 rn m m AV NE (pCT = UNIONa VASNOIV CT NE j VASHON A NE 41 RW: HITMAN NG x I = y C, Nc m tipNy AV NE CTHNE ANj I o = 2 ' 9y _ � m m l34 H IAV CTrESQ= ANACC>RTES CT NE (P 9&+TES = ¢3N SEA 9REMERTt1N - ENEI-I �i rnoTcc�� 3N Page 1 of 2 ' King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PARTI PROJECTOWNERAND PART 2 PROJECT • • PROJECT • Project Owner \✓E2—DDIJ T�y s Project Name L�—LLL=f ' Address Location L' Phone Township �� Range c s Project Engineer ,� Section � Company ESG Project Size C;Co AC Address Phone 43,112 --/3 1�1 ��'—" Upstream Drainage Basin Size AC PIART'STYPEOIPPER111111717APPILICATION7= DOE Subdivision HPA Shoreline Management Short Subdivision 04 0 Rockery Grading am Safety 0 Structural Vaults ' Commercial 0 FEMA Fioodpiain 0 Other Other COE Wetlands HPA PARTS SITECOMMUNITY AN13 DRAINAGEHASIN Comp �, ' Drainage Basin 1PARTS SITEc"ARAcTERisncs River 0 Floodplain Stream Wetlands 0 Critical Stream Reach Seeps/Springs Depressions/Swales 0 High Groundwater Table Lake Groundwater Recharge Steep Slopes Other Lakeside/Erosion Hazard • i Soil Type Slopes Erosion Potential Erosive Velocities CI Additional Sheets Attatched ' TIR WORK SHEET 1/90 I. 3 Page 2of2 ' King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PARra DEVELOPMENT REFERENCE LIMITATION/SITE CONSTRAINT Ch.4-Downstream Analysis S TVR n jf;?UAJ OFF LF. V&--S 71-tt .SrIZ5-- S jr CI 1GA S dF /At,I LX/STiiy(v "PURL/ L S In Q.wi a a Additional Sheets Attatched ESCRE43UIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION FOLLOWING CONSTRUCTION C Sedimentation Facilities EX Stabilize Exposed Surface Stabilized Construction Entrance ] Remove and Restore Temporary ESC Facilities Perimeter Runoff Control Clean and Remove All Silt and Debris Clearing and Grading Restrictions Ensure Operation of Permanent Facilities Cover Practices Flag Limits of NGPES Construction Sequence Other � u Other SYSTEM. Grass Lined Channel Tank Infiltration Method of Analysis Pipe System 0 Vault Depression 1,111M. Open Channel Energy Dissapator Flow Dispersal Compensation/Mitigation 0 Dry Pond 0 Wetland Waiver of Eliminated Site Storage Wet Pond 0 Stream Regional Detention Brief Description of System Operation i ' Facility Related Site Limitations Additional Sheets Attatched Reference Facility Limitation structuralPART11' STRUCTURAL ANALYSIS (May require,special Drainage Easement Cast in Place Vault Other Access Easement 0 Retaining Wall Native Growth Protection Easement Rockery>4'High Tract Structural on Steep Slope Other OF - • • I or a civil engineer under my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the //J attatchments. To the best of my knowledge the information provided here is accurate. TT.R WORK SHEET 1 L E z DRAINAGE REPORT CONTENT LIST ' A.) Stamped and signed by a Registered Washington P.E. on front page. Complete Technical Information Report (T1R) Wcrksheet that is enclosed. (see attached) B. Briefly describe the construction involved. C. Describe existing and proposed on-site drainage features. D. Core and Special Requirements: 1. Show that Core Requirements 1-5 in Section 1.2 are addressed. 2. Show that all Special requirements in Section 1.3 that are applicable to this project are addressed. E. Use the SBUH/SCS hydrograph method to compute required on-site detention. (Using 2,10, ' and 100 24 hour design storm events for pre-developed and post-developed conditions (6 separate peak flows). This should show sizing for the peak rate runoff control facility, with a routing table. iF. Bicfiitraticn design caics (per Section 4.6), if for project site sub-basins with more than 5C00 square feet of new impervious area subject to vehicular use or storage of chemicals. ' G. Wet pond sizing design caics (if there is more than 1 acre of new paved impervious area and meets other conditions of Special Requirement #4). H. Conveyance velocity calculations (show that major conveyance pipes velocity >- 3 fps). 1. Conveyance capacity calculations. Show that all conveyance pipes on-site have capacity for the ' 25-year design event (Hydraulic grade line > - 0.5 feet below rim of struCure). Also show that the 100-year event conveyance fulfills Core Requirement #4. J. A Level 1 Downstream Analysis, as described in Core Requirement #2. (Level 2 or 3 analysis may be requested later if a downstream problem is found or anticipated from review of the initial submittal of the Drainage report). ' TEMPORARY EROSION/SEDIMENTATI N N O CONTROL ' A. Proper design for containment of erosion on-site shown on construction plans. B. Calculations for a sediment trap (for sites less than 3 acres) or a sediment pond (for larger than 3 acres), as shown in Section 5.4. ALL REFERENCES REFER TO THE 1990 KING COUNTY SURFACE WATER DESIGN MANUAL. REPORT CHECK LIST I. 3 1 1 i 1 i 1 TIR SECTION II 1 PRELIMINARY CONDITIONS SUMMARY 1 1 1 1 1 1 1 1 1 �wt t.• • • �� r \ 'yam# i��tt.SSSISS Evd AkF "�'`� � ■ 1 bra 11 .� 'r,J; r 1 .�, ,k �� t I nit • L, 77Jrn AmC • I AgD ti.. EEC �yi;^ �„ • ■ � •/ � i• •i''�/ 7'� 1 , �;' � ,^'y. 1 .�.Ak4 S [1�p w4:� j Ur I :' 1 ,I •• PROJECT ' !•• LOCATION 'f • . top f Z+ ' SOURCE: U.S.D.A. ' SOIL TYPES AmC (ARENTS, ALDERWOOD MATERIAL) 1 SOIL MAP II. 1 wi N ?,5cb5 C 9:v SIR ..� x ti r Y FF1�p�,•Y:pYoemanes. `• k• :':Jk»M:NYSt.OwoPaNCaooc'�'� .�.: >fi .:sr"yys«�a ""k �"' 43h daY`' go .i1�"' S. .? so i • Ol PROJEC h OV^11 ?'.� ON :. s "tts ' ' w a � _ �� -� ^� �'..i''<s>��n�^°'* y±•s� ;'sa�a�sas`�� n .9 � � au+ :ram x � yia x: : ir rx SCALE 1"= 500' USGS MAP II. 2 y KING COUNTY, WASHINGTON, SURFACE WATER L• ES1GN ImANUAL 'FIGURE 3.5.1F 25-YEAR 24-HOUR ISOPLUVIALS `'f------ - - - - `�rw- ram+►- =�•- �T.:-• ---•�--- - lies P9 i — .� 45 �� / i_,.. � .,^ � - y it .� , �:•� , S .r- r ft rvw — PROJECT > - LOCATION �--1� •� �" 41 VAN s R 1 f -YEAR 24—HOUR PRECIPITATION toll, E c''rr 55 4 ISOPLUVIALS OF 25-YEAR 24-HOUR TOTAL PRECIPITATION IN INCHES njy 6 r 4 o 1 2 s ° 5 e ' s Miles 25 Y R 24 MR I 80PUV I AL CHART'') _ _°� r► ,ram' II. 3 1/90 1: 30u,uJ0 1� , 1 �, _ w I . c ,fug: ►�► ,r G r TIR SECTION III ' OFFSITE ANALYSIS ' TIR SECTION III OFFSITE ANALYSIS CORE REQUIREMENT #2 ' UPSTREAM/DOWNSTREAM ANALYSIS: The project site is located within the North Renton Drainage ' Basin Area which is a sub-basin of the larger Cedar River Basin . All Stormwater generated uphill of the project location is directed away from the site. Parallel to the lot's North property ' line, N.E. 13th Street intercepts offsite runoff by means of a curb and gutter diverting it's flow in a Westerly direction. The parking lot area adjacent to the East property line is sloped directing it's storm water in a Southerly direction. ' The existing onsite drainage basin slopes South at about 1%t and is . 16 acres in area. Storm water runoff generated on site leaves ' the site as sheet flow though well maintained short grassed terrain. The developed landscape will contain about 4,980 a£ of impervious roof and paving surfaces which will direct most of the ' site's runoff through a proposed conveyance system consisting of two catch-basins and a single 12" CMP pipe. This pipe will tie into an existing storm drainage system located below N.E. 13th Street at a proposed catch-basin. This existing storm sewer is a ' 12" concrete pipe and slopes at 3% in a Westerly direction to a catch-basin located at the intersection of Kirkland Avenue and N.E. 13th Street. From here the Storm runoff is conveyed by means of a 12" concrete pipe in a Southerly direction along Kirkland Avenue to Sunset Boulevard N.E. The increase in storm water generated by the use of impervious material in construction is expected to be minimal and not should not produce any adverse effects on the existing conveyance system. t III. 1 ' CORE REQUIREMENT 01 DISCHARGE AT NATURAL LOCATION: The runoff from the subject site currently flow off-site as sheet flow through the adjacent property to the South and is later intercepted by Kirkland Avenue N.E. From here the storm water runoff becomes incorporated into the public storm drainage system by a catch basin located on N.E. 13th Street. The natural discharge location will be preserved after development. All on-site storm water runoff will be collected in proposed catch basin #1 and will enter the public conveyance system located within N.E. 13th Street. Even though the storm ' drainage course has been change slightly(no longer crossing the property to the south) on-site runoff will still become incorporated into the pubic drainage system within Kirkland Avenue N.E. futher downstream. III .2 r r r r r r TIR SECTION IV rRETENTION/DETENTION ANALYSIS 3 DESIGN r r r r r r r r r r r r ' TIR SECTION IV DETENTION/RETENTION ANALYSIS & DESIGN ' Since the total increase in peak rate, storm runoff after development is less than 0. 5 cfs for the 100 year storm event, this project is exempt from providing runoff control as outlined in core requirement #3 of the 1990 K. C. Surface Water Design Manual. The predeveloped and the postdeveloped peak runoff rates for the 100 year storm event was determined to be 0. 11 cfs and 0. 19 cfs respectively. All storm runoff generated on impervious surfaces will be conveyed directly to an existing storm sewer below N. E. 13th Street. IV. 1 HYDROLOGIC DIST 223' - BASIN // LAWN CN = 86 IMPER. CN = 98 EXISTING �� : I S=0.01 FT T PAVEMENT �' TC= IMPERVIOUS ' ;y SH E LO 1 BASIN AREA = 10,645 SF = .24 AC IMPERVIOUS AREA 833 SF .02 AC CN=98 PERVIOUS AREA 9,812 SF = .22 AC CN 86 N . E. 13 ST. I / /"EX4STtNG - ,P A-R4(IN G r / I • " zX —W ' � ; 8 ~-j � z / ice jLO�% 2' � ao02 jm- V) �- /" - I I � !_ d ♦ ,'� zd EXISTING a0 Z qx ;' i / ♦ / ROCKERY a L- - - - - -� / ♦ /' / s A w� LOT 1 I- - - -- -- -- -75-.-3* / 76.08' - - - - - - - - - - - =4 - _ _- - - - -- - - - - - - - - - -- -sue - -- I- _ _ - - -I- - - - - - - - - _ - - - - - - - - - - - - - - - I f - - - ,I — - - - im i i I L - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SCALE: lwx20' m IV. 2 i ' REACH #1 � HYDROLOGIC DIST NCE = 47 LF SLOPE _ .01 FT FT SHEET FLOW REACH #2 HYDROLOGIC DISTANCE = 42 LF SLOPE = 08 FT/FT SHEET FLOW TOTAL BASIN AREA = 10,645 SF = .24 AC TOTAL IMPERVIOUS AREA = .6,000 SF = .14 AC ,CN=98 TOTAL GRASS AREA =4,645 SF = .11 AC CN = 86 N . E. 13 ST* - - - - - - - - - - - - - - - In l - - _ C1 ( � 3 75.19 SCALE: 1's20' f� l n _ , C. , ISTtG; r �. _ �,. P`,o o v TARE 9 :..:1:::.. ` :.f - - - - - - LOT 2 ?C IMPERVIOUS AREA w ............ ... . to I I Iuj s O z o C� :.: w x w CB 1 \ o ~—J TYPE, I ::..'`t'.'`'`: a: ::: Z w I I I�_ G.E. 3521.90 EXISTING I.E. 349.168 ROCKERY W � � d IWp 13S6 o A wcQ 10 OPTIONAL \ A -75 76.08' SIDEWAL `ems - - --- - �- 41_ _ - - - - - - - - — - - - DAE I I - - - - - - - - - - — - - - - - - - - - - - - -��`- - - - - - - - - - - - - - - - - - -' ,C- - - - - - - - - - � m �- mm I I- -- -- -7 - - - - - - - - - �. - 1 - - - - - - - - - - - - - - - - - - - - N 11- V. 3 I I O i1v!S RESCO, Inc. page KIRKLAND AVE 4-PLEX ' 100 YEAR STORM DETAIL BASIN SUMMARY BASIN ID: 100P NAME: 100 YEAR. PREDEVELOPED ' SBUH METHODOLOGY TOTAL AREA. . . . . . . . 0. 24 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3. 90 i aches AREA. . : 0. 22 Acres ' TIME INTERVAL. . . . : 10. 00 rn i ri CN. . . . : 86. 00 TIME OF CONC. . . . . �1. 06 min IMPERVIOUS AREA ABSTRACTION COEFF; 0. 20 AREA. . : 0. 02 Acres ' - CN. . . . _ 98. 00 TcReach Sheet L: 00 ns:0. 1500 pcyr : 2. 00 s:0. 0100 PEAK RATE: 0. 11 cfs VOL: 0. 05 Ac-ft TIME : 480 rnir, ' TIME DESIGN TIME DESIGN TIME DESIGN TIME DESIGN TIME DESIGN TIME DESIGN RUNOFF RUNOFF RUNOFF RUNOFF RUNOFF RUNOFF (gain) (cfs) (rain) (cfs) (gain) (cfs) (coin) (cfs) (Ain) (cfs) (®in) (cfs) ' 10 358 0.0178 �690 �0.03 4 1030 ^0.02M 1370 0.0205 1710 20 360 0.2196 700 0.0350 1040 0.0216 1380 0.0205 1720 ' 30 370 1,0211 710 0.0348 1050 8.0212 1390 0.0285 1730 40 380 0.0225 720 0.0346 1060 0.0208 1400 0.3205 1740 50 0.0001 390 0.0238 730 0.0345 1070 0.&W 1410 0.0205 1750 68 8.0002 400 0.0250 740 0,0345 1088 0,0205 1420 8,0205 1760 70 0.0804 418 0.0277 750 0.0345 1090 0.0204 1430 0.0206 1770 80 0.0085 420 0.0317 760 0.0345 1100 0.0203 1440 0.0206 1780 90 0.0006 430 0.0350 770 0.0335 1110 0.0202 1450 0.0177 1790 ' 100 0.0807 440 0.0400 780 0.0318 1120 0.0202 1460 0.0128 1800 110 0.w 450 0.0463 790 0.0306 1130 0.02-02 1470 0.0093 1810 120 0.0011 460 0.0598 800 0.0298 1140 0.0202 1480 0.0067 1820 130 0,1112 470 1,INI 810 0,0292 1150 1,IM 1490 0,0048 1830 140 0.0013 480 0.1100 820 0.0288 1160 0.0202 1500 0.0035 1840 150 0.0014 490 0.1054 830 0.0285 1170 0.0202 1510 0.0025 1850 160 0.0015 500 0.0946 840 0.0283 1180 0.8202 1520 0.0011 1860 170 0.0017 510 0.0843 850 0.0281 11W 0.0202 1530 0.0013 1870 180 0.0018 520 0.0770 860 0.0281 12N 0.0202 1540 0.0010 1880 190 0.0020 530 0.0690 870 0.0280 1210 0.0203 1550 0.0007 1890 ' 200 0.N23 540 0.0606 880 0.0280 1229 0.0203 1560 0.0005 1900 210 0.0027 550 0.0546 890 0.0275 1230 0.0203 15,78 0.0004 1910 220 0.*33 560 0.0503 900 0.0267 1240 0.0203 1580 0.0003 1920 ' 230 0.0041 570 0.0473 910 0.0261 1250 0.0203 1598 0.0802 1930 240 0.MO 580 0.0451 920 0.0257 1260 0.3203 1600 0.Ml 1940 250 0.0060 590 0.0436 930 0.0254 1270 0.0203 1610 1950 268 0.0070 600 0.0426 940 0.0252 1280 0.2204 1620 1960 ' 270 0.0079 610 0.0419 950 0.3251 1290 0.0204 1630 1970 280 0.W89 620 0.0415 %0 0.0250 1300 0.0204 1640 1980 290 0.0101 630 0.0412 970 0.0250 1310 0.0204 1650 19% 300 0.0115 640 0.0411 980 0.0249 1320 0.0204 1660 2000 310 0.0129 650 0.0480 990 0.0249 1330 0.2204 1670 2010 320 0.0141 660 0.0382 1000 0.0249 1340 0.3204 1680 2020 ' 330 8.0151 670 0,0369 1010 0.0242 1350 1,M 1690 2030 340 0.0163 680 0.0361 1020 0.3230 1360 0.0205 1700 2048 PREDEVELOPED BASIN HYDROORAPH 2/13/92 RESCO, Inc. oage � KIRKLAND AVE 4-PLEX 100 YEAR STORM ===================================================================== N� DETAIL BASIN SUMMARY N� BASIN ID: 100D NAME: 100 YEAR DEVELOPED ~~ SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0. 24 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3. 90 inches AREA. . : 0. 10 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00 TIME OF CONC. . . . . : 9. 38 min IMPERVIOUS AREA N� ABSTRACTION COEFF : 0. 20 AREA. . : 0. 14 Acres CN. . . . : 98. 00 TcReach - Sheet L: 47. 00 ns:0. 1500 p2yr: 2. 00 s:0. 0100 TcReach - Sheet L: 42. 00 ns:0. 0110 p2yr : 2. 00 s :0. 0800 N� PEAK RATE: 0. 19 cfs VOL: 0. 06 Ac-ft TIME: 480 min TIME DESIGN TIME DESIGN TIME DESIGN TIME DESIGN TIME DESIGN TIME DESIGN RLWOF 0UNOF 0JWF RLPCF 0JNOF 0WF (min) (cfs) (min) (cfs) (min) (cfs) (min) (cfs) (min) (cfs) (min) (cfs) 10 350 0,0348 690 0.0375 1@30 0.0217 1370 0,0216 1710 20 360 0.0378 700 0.0375 104 0.0215 13N 0.0216 1720 30 370 0.0390 710 0.0376 1050 0,0214 1380 0.0217 1730 40 0.8006 380 0.0398 720 0.0276 1NU 0,0214 1400 0.0217 1740 50 0.0018 390 0.3404 730 0.0377 1070 0.0214 1410 0.0217 175N 60 0.0031 400 0.0409 740 0.0377 1080 0.0214 1420 0.0217 1760 70 0.0043 410 0.0473 758 0.0378 1090 0.0214 1430 0.0217 1770 80 0.8053 420 0.0557 760 0.0378 1100 0.0214 1440 0.0217 1780 90 0.w 430 0.N588 770 0.0351 1110 0.0215 1450 0.0141 179W 101 0.1119 4411 0.0676 780 0.0816 1120 0.0215 1460 0.1043 1800 1tN 0.0083 450 0.0782 790 0.OM 1130 0.0215 1470 0.0013 1810 ~~ 120 0.0098 460 0.\N86 800 0.0202 1140 0.0215 1480 0.0004 1820 130 0.8107 470 0,1796 810 0.N301 1150 0.0215 1490 0.0001 1830 140 0.0114 480 0.1916 820 0.0301 I160 0.0215 1500 1840 150 0.0119 490 0.1356 83N 0.M301 1170 0.0215 1510 1850 160 0.0124 500 0.0956 840 0.&301 1180 8.0215 1520 1860 170 0.0137 510 0.0758 850 0.03W2 1190 0.0215 1530 1870 180 0.0152 520 0.0699 860 0.NJN2 120N 0.0215 1540 1880 190 0.3168 530 0.0602 870 0.0302 121N 0.0215 1550 1890 211 0.0161 5411 0.0491 IN 0.0312 1221 0.0215 1511 1900 210 0.0173 550 0.W1 890 0.0290 1230 0.0215 1570 1910 220 0.0179 560 0.0451 900 0.0273 1240 0.0216 1580 1920 230 0.8196 570 0.0449 910 0.0268 1258 0.0216 1590 1930 240 0.0217 580 0.0440 920 0.0286 1260 0.0216 1600 1940 N� 250 0.0228 590 0.0450 930 0.0266 1270 0.0216 1610 1950 260 0.3235 600 0.0451 940 0.02266 1280 0.0216 1621 >%@ 270 0.0242 611 0.0452 956 0.0266 1290 0.1216 1630 1970 280 0.0247 620 0.0453 960 0.0266 1300 0.0216 1640 19N 290 0.0268 630 0.0454 970 0.K67 1310 0.4216 1650 199N 300 0.0294 640 0.0455 981 0.0267 1320 0.1216 1660 2001 0� 310 0.0306 650 0.0427 990 0.0267 1330 0.0216 \670 2010 320 0,0313 660 0.0390 1000 0,0267 1340 0.0216 1600 2020 330 0.0319 670 0.0879 1010 0.0249 1350 0.0216 1690 2038 340 0.0325 680 0.0376 1020 0.N224 1360 0.0216 1700 2040 POSTI)EVELOPED BASIN HYDROGRAPH U� %V. 5 �� ' TIME_OF_CONCENTRATION_ The time of concentration used in both of the predeveloped and ' developed hydrographs where calculated per K.C.S.W.D.M. A single reach was used in developing the predeveloped hydrograph. Two reaches where used in the developed hydrograph. ' Sheet Flow: Sheet flow is flow over plane surfaces. It usually occurs in the headwater of streams. With sheet flow, the friction value (nj (a modified Manning's effective roughness coefficient that includes the effect of raindrop impact; drag over the plane surface; obstacles such as litter, crop ridges, and rocks; and erosion and transportation of sediment) is used. These n, values are for very shallow flow depths of about 0.1 foot and are only used for travel lengths up to 300 feet. Table 3.5.2.0 gives Manning's n, values for sheet flow for various surface conditions. ' For sheet flow up to 300 feet, use Manning's kinematic solution to directly compute T,: Sheet flow: TL = 0.42 (n,L)°-$ (P2) 0.5 (Sc,) 0.4 ' where T, = travel time (min), n, = sheet flow Manning's effective roughness coefficient (from Table 3.5.2C), L = flow length (ft), P2 = 2-year, 24-hour rainfall (in), (see Figure 3.5.1 C) and so = slope of hydraulic grade line (land slope, ft/ft) ' PREDEVELOPED BASIN: REACH #1 : ' L=223' MANNING N = . 15 GRASS SLOPE — .01 FT/FT TC= 31 .06 MIN. DEVELOPED BASIN: ' REACH #1 : L=47' ' MANNING N = . 15 GRASS SLOPE — .01 FT/FT T1=8.93 MIN. REACH #2: ' L=42' MANNING N = .011 SMOOTH SURFACES SLOPE — .01 FT/FT T1= .44 MIN. TC=9.38 V.SB KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL ' TABLE 3.5.2B SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS ' SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982) Runoff curve numbers for selected agricultural, suburban and urban land use for Type 1 A ' rainfall distribution, 24-hour storm duration. CURVE NUMBERS BY HYDROLOGIC SOIL GROUP LAND USE DESCRIPTION A B C D Cultivated land(1): winter condition 86 91 94 95 ' Mountain open areas: low growing brush and grasslands 74 82 89 92 Meadow or pasture: 65 78 85 89 t Wood or forest land: undisturbed 42 64 76 81 Wood or forest land: young second growth or brush 55 72 81 86 Orchard: with cover crop 81 88 92 94 ' Open spaces, lawns, parks, golf courses, cemeteries, landscaping. good condition: grass cover on 75% or more of the area 68 80 0 90 fair condition: grass cover on 50% to 75% of the area 77 85 90 92 Gravel roads and parking lots 76 85 89 91 Dirt roads and parking lots 72 82 87 89 Impervious surfaces, pavement, roofs, etc. 98 98 LW 98 Open water bodies: lakes, wetlands, ponds, etc. 100 100 100 100 Single Family Residential (2) Dwelling Unit/Gross Acre % Impervious (3) ' 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 for pervious and 2.5 DU/GA 30 impervious portion ' 3.0 DU/GA 34 of the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 DU/GA 46 ' 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 ' 7.0 DU/GA 56 Planned unit developments, % impervious condominiums, apartments, must be computed ' commercial business and industrial areas. (1) For a more detailed description of agricultural land use curve numbers refer to National Engineering ' Handbook, Section 4, Hydrology, Chapter 9, August 1972. (2) Assumes roof and driveway runoff is directed into street/storm system. (3) The remaining pervious areas (lawn) are considered to be in good condition for these curve numbers. CN CHART IV- 6 - --- L)0 ' All - .�� ,� " - � � ..ems' �►�. II s a is ZW OV H Z Ha U WW to � Z H Q U r it rr �r rr it rr i■r �r rr r r rr ■■ ar r■ jr■i ■r rr TIR SECTION V ' CONVEYANCE CORE REQUIREMENT #4 Storm water Conveyance (Overview) The Pipe capacity and flow velocities were determined by using "Flow Master" software which uses Manning' s equation for open ' channel flow. The rational method(25 year storm) was used to check this pipe for the minimum required velocity of 3.0 fps and the 100 Year Storm was used to check it for conveyance capacity. ' Since the depth of water in the proposed conveyance pipe is less than 0.5' , it can be assumed that water level after 25 year storm will never rise above 0.5' below the rim of any structure. ' Biofiltration: ' Since the total increase in area subject to vehicle use is less than 5,000 sf this project is exempt from providing a means of biofiltration as outlined in core requirement #3 K.C. Surface Water Design Manual 1990. V. 1 BE 1/4 OF SW 1/4 SEC-4, TSHP-23M, RANG-6r REACH #1 SLOPEH = .01 DFT/FT _ 47 LF SHEET FLOW REACH #2 _ HYDROLOGIC DISTANCE = 42 LF I\ °0 — SLOPE = 08 FT/FT M M o SHEET FLOW - - - - - - - - r- - - - - - - - - - - - - - - - - - - 'i' & BORE — i TOTAL BASIN AREA = 6,804 SF = .16 AC CAVE)=.73 --- -� �_ — - - -I"?- -- - - -��— _ - - - - - - - - - I , TOTAL IMPERVIOUS AREA = 5,000 SF = .11 AC ,C=.90 - - i TOTAL GRASS AREA = 1,804 SF = .04 AC C=.25 � II �- - - - - - __ - - - y- -=\ — — — —I - - - - - - - - = SCALE: 1"=40' lb \\ \ ,N CB#1 TRIBUTARY AREA a .. ..: ... .. EXISTING TREES (TYP.) CB 1 TYP Iow G.E. 52 .D.: :. >'' I.E. 9. a S a E ' o-4 _ s - PROPOSED ' � 3s, z 4-PLEX A 82 EXISTING o \ ROCKERY DATE .RAV CHECKED RFf. THOM - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - N0. 1*- V. 2 ' CONVEYANCE SYSTEM ANALYSIS AND SIZING TABLE USING THE RATIONAL METHCD � z Location Area C C•A Sum T i I Q Pi T F Sub Basin Number c R R R Pe YP• Slope : V v L Tt C� From To (ac) C•A (min.) (c.f.s. (in.) n (fiIPe (pipe Q) (min.) Fw n > z I 7, � y V - •hC . �/,' !1`^ 30 1.2 8 L .✓FCC. o�iC�.,I .�;,��3 I �� I �/'�r J-:.. � w W W ■ � I I � ; ! I I I I I � � ■ I I I I I I a i I i I I I I i i a C I I z z a i I I i I I I I I I z Project: K IE K� i!J� /a —r�L`,' I PR I Caics by: I Job No: O -+ Location: 1/4 1/4 Sec. TWP RGE. I Date: 7 Page of (0 r 0 CONVEYANCE SYSTEM CHART V. 3 ' KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL ' "C" Values The allowable runoff coefficients to be used in this method are shown in Table 4.3.3A by type of land ' cover. These values were selected following a review of the values previously acceptable for use in the Rational Method in King County and as described in several engineering handbooks. The values for single family residential areas were computed as composite values (as illustrated below) based on the estimated percentage of coverage by roads, roofs, yards and unimproved areas for each density. For drainage ' basins containing several land cover types, the following fonmula may be used to compute a composite runoff coefficient "C,.". C. = ((C, x A,) + (CZxA2)+... + (C,,)(A�))/At ' where: A, total area (acres) A,,zr = areas of land cover types (acres) C,,Z„ = runoff coefficients for each area land cover type ' TABLE 4.3.3A RUNOFF COEFFICIENTS - "C" VALUES FOR THE RATIONAL METHOD" ' GENERAL LAND COVERS LAND COVER C LAND COVER C Dense forest 0.10 Playgrounds 0.30 Light forest 0.15 Gravel areas .80 Pasture 0.20 Pavement and roofs FOT90 Lawns 0.25 3 Open water (pond, 1.00 ' - lakes, wetlands) SINGLE FAMILY RESIDENTIAL AREAS (Density is in dwelling units per gross acreage (DU/GA)) LAND COVER LAND COVER DENSITY C DENSITY C ' 0.20 DU/GA (1 unit per 5 ac.) 0.17 3.00 DU/GA 0.42 0.40 DU/GA (1 unit per 2.5 ac.) 0.20 3.50 DU/GA 0.45 0.80 DU/GA (1 unit per 1.25 ac.) 0.27 4.00 DU/GA 0.48 1.00 DU/GA 0.30 4.50 DU/GA 0.51 1.50 DU/GA 0.33 5.00 DU/GA 0.54 2.00 DU/GA 0.36 5.50 DU/GA 0.57 2.50 DU/GA 0.39 6.00 DU/GA 0.60 'For land covers not listed above, an area-weighted "C x At" sum should be computed based on the following ( zxAz) ( ) A, ( AZ p ) drainage equation: C x A, _ (C,xA, + C + ...+ C�xA� , where = A, + + ...+A„ , the total draina a basin area. ' (For use only in determining peak design flow for analyzing and sizing pipes, culverts or channels) RATIONAL 'C' CHART ' V. 4 1/90 t------------------------------------------------------------------------------ Resco --------------- Resco I Stormwater Calculations I Page 1 of I ll^o.ject-Name:-THOMPSON-4-PLEX Pr ect Date 1/31/9c ------ ----------- ------------------------------- ------------------------------------------ * * * PROPERTY DATA AREA #1 : 0. 1. 1 (acres) RUNOFF FACTOR : 0.'9 (acres) ' AREA #2 : 0. 04 (acres) RUNOFF FACTOR : 0. 25 (acres) TOTAL AREA 0. 15 (acres) Calculate Average Runoff Factor ---Area1 (Cn1 ) -+-Area2 (Cn2) - C = total area 0. 11 (0. 9) + 0. 04 (0. 25) C = --------------------------- 0. 15 ' C = 0. 727 WEIGHTED C CALCULATION V. S ----- ------------------------------------------------------ le sco I --------------------- Rainfall Factor I Page 1 of 11 ----------------------------------------------------------------------9--------- Project Name: THOMPSON 4-PLEX Project Date: 1/,31/92 ------------------------------------------------------------------------------ Ir = (pr) ( i-r) ' Total Precipitation (24 Hour, Ism�pluvials) : 3. 5 ' Time of Concent r^at i on Minutes: 6. Rainfall Unit Factor -br, it = (ar) (tc) -0. 65 0. 804 = (c. 66) (6. ,3) ' i r = 0. 804 Rainfall Intensity ' Ir = (pr) x ( ir) 2'. 81 = 3. 5 x 0. 604 ' Ir = 2. 81 -123 YEAR STORM IMTEram V- 6 -------------------------------------------------------------------------------- esco -------------------- I Rainfall Factor I Page 1 of 11 ---- -------------------------------------------g--------- Pro.ject Name: THOMPSON Project Date: 1/31/92 '------------------------------------------------------------------------------- ' Ir = (pr) ( i.r) ' Total Precipitation (24 Hour Isopli-tvials) : 3. 9 ' Time of Concentration ration Minutes: 6. 3 ' Rainfall Unit Factor ' it = (ar) (tc) -br -0. 63 0. 819 = (2. 61 ) (6. 3) ' it = 0. 819 Rainfall Intensity I = (pr) x ( ir) 3. 19 = 3. 9 x 0. 819 ' Ir = 3. 19 glaM YEAR STORM INTENSITY V. 7 ' C`IIi`culai' Channel Analysis c Design Salved with Manning' s Equation Open Channel - Uniform flew ' Worksheet Name: thom Comment : CEO #1 to� CEO #2 25 year storm peak flow ' Solve For, Actual Depth ' Given Input Data:Diameter. . . . . . . . . . 1. 00 ft Slope. . . . . . . . . . . . . 0. 0050 ft/ft Manning' s n. . . . . . . 0. 012 Discharge. . . . . . . . . 0. 33 cfs Computed Results: ' Depth. . . . . 0. 23 ft Velocity. . . . . . . . . . 2. 35 fps Flow Area. . . . . . . . . 0. 14 s f Critical Depth. . . . 0. 24 ft ' Critical slope. . . . 0. 0048 ft/ft Flercent Full. . . . . . 23. 48 % Full Capacity. . . . . 2. 73 cfs ' G?MAX @. 94D. . . . . . . . 2. 94 cfs Froude Number. . . . . 1. 02 (flow is Supercritical ) 1 ' Open Channel Flow Module, Version 3. 21 (c) 1990 Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 0E708 PIPE SIZING 23 YR. (MANNING) ' V. 8 ' Circular Channel Analysis & Design Sored wit ;��rrirg' s Eq _at i �nl _ Open Channel - Uniform flow Worksheet Name: thom Comment : CB #1 to CB #2 100 year storm peak flow Solve For- Actual Depth Given Input Data: ' Diameter. . . . . . . 1. 00 ft Slope. . . . . 0. 0050 ft/ft Mann i n g' s n. . . . . . . 0. 012 Discharge. . . . . . . . . 0. 38 cfs Computed Results: Depth. . . . . . . . . . . . . 0. 25 ft ' Velocity. . . . . . . . . . 2. 45 fps Flow Area. . 0. 16 sf Critical Depth. . . . 0. 25 ft t Critical S.lope. . . . 0. 0048 ft/ft Percent Full. . . . . . 25. 21 % Full Capacity. . . . . 2. 73 cfs QMAX ib. 941). . . . . . . . 2. 94 cfs Froude Number.. . . . . 1. 02 (fly-w is Supercritical ) t Open Channel Flow Module, Version 3. 21 (c) 1990 ' Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 ' PIPE SIZING 100 YR. (MANNING) V. 9 1 i 1 1 i TIR SECTION VI SPECIAL REPORTS AND STUDIES i 1 i i 1 i i 1 1 1 1 1 1 1 1 1 TIR SECTION VII BASIN COMMUNITY PLAN AREAS 1 1 i 1 1 1 1 i 1 i 1 1 1 TIR SECTION VIII ' OTHER PERMITS 1 ' TIR SECTION IX EROSION, SEDIMENTATION CONTROL DESIGN t t t TIR SECTION IX ' EROSION SEDIMENTATION CONTROL DESIGN CORE REQUIREMENT #S SEDIMENTATION : ' Volumes of sedimentation to be expected due to erosion during the construction process are expected to- be minimal . To eliminate the ' threat of downstream siltation damage, a construction entrance, silt fencing, and catch basin protection have been planned as part of the temporary erosion control plan as outlined by the ' 1990 K.C. Surface Water Design Manual . 1 1 t ' IX. 1