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HomeMy WebLinkAboutSDP200900096 Calculations Final Site Plan and Comps. 2009-11-23 VIA & WHITMAN , REQUARDT & ASSOCIATES , LIP ENGINEERS • ARCHITECTS • PLANNERS EST. 1915 November 23, 2009 Mr. Gerald Gatobu Albemarle County Department of Community Development 401 McIntire Road Charlottesville,VA 22902-4596 Re: Albemarle County Service Authority-Camelot Pump Station-Final Site Plan Submittal WR&A W.O. #46466-002 Dear Mr. Gatobu: Transmitted with this letter are eight (8) copies of the final site plan for the Camelot Pump Station. The Camelot Pump Station is part of the North Fork Regional Pump Station project for the Albemarle County Service Authority (ACSA). As you know, Whitman Requardt & Associates (WR&A) is the design engineer for this project. In addition to the eight copies of the site plans,the following is included in this transmittal: • Review fees from the ACSA • Application for Site Development Plans • Final Site Development Plan Checklist • Erosion and Sediment Control Application Form • Rendering for Proposed Camelot Pump Station building(included as Attachment A) WR&A has obtained a determination for Architectural Review Board (ARB) for the Camelot Pump Station. The determination was made that the pump station would comply with the rendering included in Attachment A. The site plan review and approval would be performed by Planning staff. A formal review,presentation, and approval by the ARB is not required. In addition to transmitting the final site submittal for the Camelot Pump Station, the intent of this letter is to review storm-water quantity and quality management for the pump station site and WWTP site. CAMELOT PUMP STATION AND WWTP ABANDONMENT OVERVIEW The Camelot Pump Station site will be situated south of and immediately adjacent to the existing Camelot WWTP. The parcel to be subdivided for the pump station is currently owned by HMC 9030 Stony Point Parkway, Suite 220, Richmond,Virginia 23235 www•wrallp.com Phone: 804.272.870o Fax: 8°4.272.8897 Baltimore, MD • Fairfax,VA • Georgetown, DE • Newport News,VA • Pittsburgh, PA • Richmond, VA • Wilmington, DE • York, PA N:\46466-002\Engineering\Corresp\Letters\112309 Camelot Site Plan Submittal ltr.doc Mr.Gerald Gatobu Page 2 Albemarle County Department of C‘,....:tunity Development November 23,2009 Holdings, LLC (HMC). The proposed area of land acquisition from HMC by the ACSA is 0.60 acre. Following the construction of the pump station and the improvements shown on the transmitted site plan,the pump station site will have 0.04 acre of impervious cover while 0.49 acre of the property will remain vegetated after construction. The vegetated and undisturbed portion of the property is the floodplain of the North Fork of the Rivanna River. This portion of the property will remain undisturbed and vegetated as the ACSA has no plans for future site improvements in the floodplain. The Camelot Pump Station will replace the Camelot WWTP which currently resides on a 1.23 acre lot immediately adjacent to the pump station site. The Camelot WWTP site currently has 0.07 acre of impervious cover(5.7% of the total property area). The remaining 0.80 acre of the property is heavily vegetated. The 0.07 acre of impervious area within the Camelot WWTP site does not include the primary treatment basins and the existing storage tank within the site. The total area of the treatment basin and tank equal an additional 0.07 acre. Upon construction and successful start-up of the Camelot Pump Station, the Camelot WWTP will be decommissioned, demolished, backfilled, graded, compacted, and seeded. The removal of the Camelot WWTP will result in a total of 0.14 acre of land that will be restored to its original grassed or vegetated state. In addition, the existing discharge from the Camelot WWTP will be eliminated, resulting in reduced pollutant (nitrogen and phosphorus) loads and the elimination of a major point source discharge to the North Fork of the Rivanna River. STORM-WATER MANAGEMENT REVIEW AND DETERMINATION Storm-Water Quality Review WR&A recently met with the Department of Community Development to review storm-water quality control for the Camelot Pump Station and the decommissioning of the Camelot WWTP. Following an overview of the sites'drainage patterns, it was determined that the Camelot Pump Station site will be considered as a redevelopment area with regard to storm-water quality control as shown on the County's Water Protection Ordinance computation spreadsheet. Following a review of the area types outlined in the spreadsheet, the Camelot Pump Station and the decommissioning of the Camelot WWTP do not fall under the area type of"Rural Land". In addition, a review of the County GIS layers revealed that the project sites are not in the area type of "Drinking Water Watersheds". As a result, it is WR&A's opinion that the Camelot Pump Station and Camelot WWTP fall in the area type of"Development Area". Two methods were used to confirm the need for storm-water quality control for the Camelot Pump Station and the decommissioning of the Camelot WWTP. These methods are summarized as follows: • Offsite and Onsite Drainage to a Point of Analysis -Under this method, the offsite and onsite drainage that is not conveyed in a separate storm drain system is analyzed at a single point of analysis on the Camelot WWTP site. The drainage area is 0.77 acre. The pollutant loads and N:\46466-002\Engineering\Corresp\Letters\112309 Camelot Site Plan Submittal ltr.doc Mr.Gerald Gatobu Page 3 Albemarle County Department of Cc___:`tunity Development November 23,2009 required pollutant removal for this method are shown on Worksheet 1 of the Water Protection Ordinance computation spreadsheet and are illustrated on Figure 1. Worksheet 1 and Figure 1 are included in Attachment B. • Parcel Area Drainage to River—Under this method, the total of the Camelot Pump Station and Camelot WWTP parcel areas are evaluated for pollutant loads and removal requirements. The drainage area is 1.83 acres (0.60 acre for the Camelot Pump Station site + 1.23 acres for the Camelot WWTP site). The pollutant loads and required pollutant removal for this method are shown on Worksheet 2 of the Water Protection Ordinance computation spreadsheet and are illustrated on Figure 2. Worksheet 2 and Figure 2 are included in Attachment C. The results of each of these methods are described in the following subsections. Offsite and Onsite Drainage to a Point of Analysis A drainage area of 0.77 acre is shown in Worksheet 1 and on Figure 1. This drainage area is a combination of existing offsite and onsite areas as shown on Figure 1. The existing offsite impervious area is 12,000 square feet. This existing offsite impervious area is shown under both the pre- and post-construction tabulations. Worksheet 1 shows the pre-development and post-development impervious cover equaling 45%. Even with the same impervious area (as a function of percentage) in the pre-and post-construction conditions, the worksheet shows that the required pollutant removal is 9%for the "Development Area" area type. As summarized above, the area within the existing floodplain of the North Fork of the Rivanna River will remain undisturbed, vegetated, and will function as a vegetative filter. This existing vegetative filter is approximately 1.3 acres in area. Based on the 9% required pollutant removal, a vegetative filter strip is an appropriate selection as an adequate Best Management Practice (BMP) as outlined in Table 1 in Chapter 1 of the Virginia Storm-water Management Handbook(VSM Handbook). Based on this analysis and the understanding that the existing floodplain will remain and act as a vegetative filter, an additional BMP for storm-water quality management is not warranted under this method of analysis. Parcel Area Drainage to River A drainage area of 1.83 acres is shown in Worksheet 2 and on Figure 2. This drainage area is a total of the parcel areas of the Camelot Pump Station and the Camelot WWTP sites. Using the sum of the parcel areas as the drainage area and the pre- and post-construction impervious areas for both parcels, Worksheet 2 shows that both the pre- and post-construction impervious areas equal 3 percent. Similar to the method outlined above, the development of the Camelot Pump Station and the decommissioning of the Camelot WWTP results in no net increase in impervious area for the combination of these two parcels. N:\46466-002\Engineering\Corresp\Letters\112309 Camelot Site Plan Submittal ltr.doc Mr.Gerald Gatobu -- Page 4 Albemarle County Department of C ___nunity Development ) November 23,2009 In addition, Worksheet 2 tabulates the required pollutant removal to be a negative number for the "Development Area" area type, under the Redevelopment area of the worksheet. This result clearly indicates that a BMP is not needed based on this analysis method. Storm Water Quantity Review Figures 1 and 2 as included in Attachments B and C, respectively, show that most of the offsite drainage will be conveyed through a new storm drainage system. The conveyance of this offsite drainage through a new system is meant to maintain the existing drainage pattern at the Camelot Pump Station site. The new storm drainage system is also detailed on the transmitted site plans. The system is sized for the 10-year storm event. As part of storm-water quantity review, Minimum Standard (MS) 19 must also be reviewed for this new point source discharge to confirm that an adequate receiving channel exists. Sheet C1-03 in the submitted site plan shows the cross-sections of the receiving channel. The cross-sections and tabulation shown on Sheet C1-03 indicates that the existing channel at the discharge location of the new storm drainage system has the necessary depth to convey the design flows. To control velocity under the design storm, a permanent rip rap outfall has been designed and shown on the submitted site plan. As indicated on Sheet C1-03, the discharge velocity is 1.54 fps at the rip rap outfall, resulted in a non-erosive discharge condition. The discharge velocity at cross-section 0+00 (which is below the outfall, at existing grade) is 2.58 fps. This discharge velocity is also considered non-erosive for a heavily vegetated floodplain and overland area. Based on the results of this analysis, MS-19 has been satisfied. The storm sewer design computations and hydraulic grade line computations are included in Attachment D. The open channel flow computations for the cross-sections used for the MS-19 analysis are included in Attachment E. Based on no-net increase in impervious area as summarized above and compliance with MS-19, storm-water quantity control is not warranted for the Camelot Pump Station and for the decommissioning of the Camelot WWTP. Storm-Water Management Review Conclusion Based on the storm-water quality and quantity review outlined in this letter, the supporting attachments, the information contained on the site plans, and the removal of the existing point source and process discharge of the Camelot WWTP, storm-water quality and quantity control for the Camelot Pump Station and for the decommissioning of the Camelot WWTP are not warranted. N:\46466-002\Engineering\Corresp\Letters\112309 Camelot Site Plan Submittal ltr.doc Mr.Gerald Gatobu Page 5 Albemarle County Department of Development % November 23,2009 We trust that this letter adequately summarizes our analysis and transmits the required information for final site plan review. Should you have any questions, please do not hesitate to call. Thank you for your cooperation in this matter. Very truly yours, Whitman,Requardt&Associates,LLP Charles Luck, P.E. 'Associate Enclosures cc: Tom Garrison—ACSA File 46466-002 N:\46466-002\Engineering\Corresp\Letters\112309 Camelot Site Plan Submittal ltr.doc ' J Attachment A Renderings for Proposed Camelot Pump Station Building 1 M + i Attachment B Worksheet 1 and Figure 1 . Short Version BMP Computations For Worksheets 2-6 Albemarle County Water Protection Ordinance: Modified Simple Method CAMELOT PUMP STATION Plan: WORKSHEET NO.1 Water Resources Area: Development Area Preparer: YLM Date: 18-Nov-09 Project Drainage Area Designation DA#2 L storm pollutant export in pounds, L=[P(Pj)Rv/12][C(A)2.72] Rv mean runoff coefficient, Rv=0.05+0.009(1) Pj small storm correction factor,0.9 I percent imperviousness P annual precipitation,43"in Albemarle A project area in acres in subject drainage area, A= 0.77 C pollutant concentration,mg/I or ppm target phosphorus f factor applied to RR ✓ required treatment volume in cy,0.5"over imperv.area= A(I)43560(0.5/12)/27 RR required removal, L(post)-f x L(pre) %RR removal efficiency, RR100/L(post) Impervious Cover Computation(values in feet&square feet) Item pre-development Area post-development Area Roads Length Width subtotal Length Width subtotal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Driveways Length Width no. subtotal Length Width no. subtotal and walks 0 0 0 12000 0 0 0 12000 0 0 0 0 0 0 0 2175 1 0 12000 0 0 0 0 14175 Parking Lots 1 2 3 4 1 2 3 4 __ 01 0 0 t [ 0 0 Gravel areas Area i 3778 Area 734 x 0.70= 2644.6 x 0.70= 513.8 Structures Area no. subtotal Area no. subtotal 0 0 608 0 0 300 0 0 0 0 0 0 0 0 0 608 0 300 Actively grazed pasture& Area I Area yards and cultivated turf x 0.08= 0 0 x 0.08= 0 Active crop land Area Area x0.25= 0 x0.25= 0 Other Impervious Areas 0 0 Impervious Cover 45% I(pre) l(post) Rv(post) V 0.45 23.1 New Development(For Development Areas,existing impervious cover<=20%) C f I(pre)* Rv(pre) L(pre) L(post) RR %RR Area Type 0.70 1.00 20% 0.46 2.17 2.14 -0.03 -2% Development Area 0.35 1.00 0% 0.46 1.09 1.07 -0.02 -2% Drinking Water Watersheds 1 0.40 1.00 1% 0.46 1.24 1.22 -0.02 -2% Other Rural Land *min.values Redevelopment(For Development Areas,existing impervious cover>20%) C f I(pre)* Rv(pre) L(pre) L(post) RR %RR Area Type 0.70 0.90 20% 0.46 2.17 2.14 0.18 9% Development Area 0.35 0.85 0% 0.46 1.09 1.07 0.15 14% Drinking Water Watersheds 0.40 0.85 1% 0.46 1.24 1.22 0.17 14% Other Rural Land Interim Manual,Page 70 rev. 16 Feb 1998 GEB \ Mad Box WMIMI_ ....,_ iiir � \ \ . . _ ,.._ ,, _ — -� _-, .,,,,,,„,„ ....._ ..;.. , . . ... 0/,:inb pc,/,....._ 4 0/J 1/5/7 — F__ ± _' II i'T! % QOI� j0! t,, r y 6 „ .. I . r _ t� oil,N 'ilt, „,,j'. Ij' \ 1 m l •Lwr, . ; Illgik \Furl- !�R! EX. 20'Water Lme Esmt- 6. -- 14) Ilk IN y_ �i� O B. /505, PG. 56/ U �� ,r V im. •A �~\ YI\ . i _ __ -..pha/t $ Grave/ / - 405 �_��� \Parking Lot O 04‘0) 0 �' i ,/ar, 1 1. \ \ O 0 Q� ,; ,. • .,.v .) qk ----A\ \i.1 ? Se-:70 - ir fi') - O r'.,. tf7V .fie r Aspha/t o _;,`:..av r; / Story Frame v Parking Lot _co to f ''4t.')" am I #430/ L \ER© :04.44:4 :f f l BACK BOARD _\ I W e"Cl° Jsat.) ' 4 N x O. I N 0 c z O N LD 0 4)110 11 : 11 \1\1 \ Grave/Lot #03200-00-00-005 0 l V l \f/MC/TOLD/N65, LL ``'O l 6IGraI1 \ o �0 D.B• 3�28, PG. 58 � I �, PLAT. D.B /, P6 3 / Tit 1; ' 1 \ 4 .I i II \ V v2 O\ I + 1. .. Bo//aids (5)3 / 1- 0 I / , II I J \ o •g� ` 4 I ( I 14\ ' \ #032 C/T/RO00C 05E0 1 '' I ,for I 'I I. 0 ., \ \ \D.B• 3583, P6. 640 / Story ` �' I k 6 I PLA r- 1.5. 92/, P6. 533 Meta/ B/ock I \ o 4f. I I I , �r` \ e Bldg. DA;2=0.77 ACRES D n I� m BE ; 1 ,�, I 11 \ \ a�► pha/ ��if, I „lb 41 43 15, O(/oo� -e�ce \ a0l o arkmg Loly , : I�, ...ill - \ E% 12" I I I N \ \ W / — . / N v _-- CULVERT 1O BE . I % \ \ \ / - EX.WM POSER POLE / ill 1 X (,,,NOIE 3) ' do .‘ ( I 10 ` N , \ \ ����/�MAILM\/I� /AIk•/ Lk z W/Barbed Wre `- _ 4q;- :.v.,,.;..: - , ���; : /%jtQ 0oI11ih1i&vin. o, kpg:l,:iti....„,,,, . % \ \ \ •, .S / \ \ �_ :�•7\,moo;: ��i ��Ti i+ i - M i ,._ Will1501-, ----__ ------- -...._-_--_- _.--ill .,..s.,..0... . . 41 lir Illux , _ , I- Eu-ii-fli,..vge,-, ..k.... :twv- • ow77,- k 4_ vv______61 0 .; a If ..,.c;.., , ..��_ .- .1'''741 .‘ 2.6:AZN 'ai*t ,.;:.:..:...� h cam., \ 01 I 1 .,3 rG ./ ,,1/4 x 1 Puna ` \ \ • =:tt; Grave/ ■ •, II! su of 0 �. . tokoo. OC ©0 p �� Paomerae(TIP.) I \ 1�.7y d Bls.. 1 Vl ____ 1 . , ) WWTP BAs/N - - _ 3. O�' .‘ I-00 005D0 su To,�sum . . VA ', WA TER S PROIEOnOH(TfP.) '- .II AWER 'oTtIOR/TY - Step5W/ Co kl WHITMAN, REQUARDT AND ASSOCIATES, LLP �7%. 76 � 272 ,o rn Engineers, Architects and Planners - LA ': D,B. .9 5 '3 o�4n�07 ��'` . ct 9030 Stony Point Parkway, Suite 220 \ J XX mot:,,.. �- �(��� t 4, Richmond, Virginia FAX: 272-8897 _ 5 C.L•P Barb !'IPT x (804) 272-8700 www.wrallp.com 0 24 • 0 ALBEMARLE COUNTY SERVICE AUTHORITY CAMELOT PUMP STATION SCALE FIGURE 1 0 40' 80' Attachment C Worksheet 2 and Figure 2 . Short Version BMP Computations For Worksheets 2-6 Albemarle County Water Protection Ordinance: Modified Simple Method CAMELOT PUMP STATION Plan: WORKSHEET NO.2 Water Resources Area: Development Area Preparer: YLM Date: 18-Nov-09 Project Drainage Area Designation DA#2 L storm pollutant export in pounds, L=[P(Pj)Rv/12][C(A)2.72] Rv mean runoff coefficient, Rv=0.05+0.009(1) Pj small storm correction factor,0.9 1 percent imperviousness P annual precipitation,43"in Albemarle A project area in acres in subject drainage area, A= 1.83 C pollutant concentration, mg/I or ppm target phosphorus f factor applied to RR ✓ required treatment volume in cy,0.5"over imperv.area= A(1)43560(0.5/12)/27 RR required removal, L(post)-f x L(pre) %RR removal efficiency, RR100/L(post) Impervious Cover Computation(values in feet&square feet) Item pre-development Area post-development Area Roads Length Width subtotal Length Width subtotal I, 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 01 _ 0 0 Driveways Length Width no. subtotal Length__ Width no. subtotal and walks 0 0 0 0 0 0 0 0 0 0 0r- 0 0 0 0 2175 j` 0 0 0 0 0' 0 2175 Parking Lots 1 2 3 4 1 2 3 4 1---- 0 ;� 0 0 0 0 Gravel areas Area 2635 Area 0 x 0.70= 1844.5 x 0.70= 0 Structures Area no. subtotal Area no. subtotal 0 0 608 0 0! 300 0 0 0 0 0i 0 0 OE 0 608 0 300 Actively-grazed pasture& Area Area yards and cultivated turf x 0.08= _ 0 0 x 0.08= 0 Active crop land Area Area x0.25= 0 x0.25= 0 Other Impervious Areas 0 0 Impervious Cover 3% I(pre) l(post) Rv(post) V 0.08 3.8 New Development(For Development Areas,existing impervious cover<=20%) C f I(pre)* Rv(pre) L(pre) L(post) RR %RR Area Type 0.70 1.00 20% 0.23 2.58 0.88 -1.71 -195% Development Area 0.35 1.00 0% 0.08 0.44 0.44 0.00 0% Drinking Water Watersheds 0.40 1.00 1% 0.08 0.50 0.50 0.00 0% Other Rural Land *min.values Redevelopment(For Development Areas,existing impervious cover>20%) C f I(pre)* Rv(pre) L(pre) L(post) RR %RR Area Type 0.70 0.90 20% 0.23 2.58 0.88 -1.45 -166%o Development Area 0.35 0.85 0% 0.08 0.44 0.44 0.07 15% Drinking Water Watersheds 0.40 0.85 1% 0.08 0.50 0.50 0.08 15% Other Rural Land Interim Manual, Page 70 rev. 16 Feb 1998 GEB II I ' / Storyl/ I I \ \ /'? -'-' Metal $ Block o \ I I 'j0. I I I ` \\ \ Bldg. I ,�y,. 1 1 \ ' I �� .i , t \\ \ 64 Bo/lards (5) \ `� Aspha/t r ill �;� (�(/oo d FeNCe . I - ' ' ?'arkingLot - li I I1� I :�_ \ o L �o I IN I II \ \ \ \ \ W / \ if II 0�r � I \ \ 1 IN : \ \ \ // --- ---- / al h I 4 1. if S>,:, \A ‘ \ \ ' ileI �� \\—Comb. _bed Wire w��►,,�i�.1/2A� ��►��_� I .,,,'� o I,��� • \ \ Te% — --3e' . -i 2�.r►'�r� !� ���� �\ i.'N Block �_ -- -� -1 ' ''� Y emr-..'/. �_ �ldg. -. /11, �- Ili -- X irr- \ �o _ B�.\ �i. S4! \ Ogna tC o I .AfROX. 00A , I , / 5 -W . ,, ' 1%, - •1 '• `s \� � , 5EE- _ - 1 I .B .3 G, is/ .. , PUM \ CONT / _____ il.mo \ I Grave/ \I - let , -sory ' )IL _ ' WOO." :oc Alik � _ She B/...�, ,,- _ __ \ -� -� ^x WIT 5A5/N !� \ ` _ Deck W/ _ _ — u� Steps � —T; ---,9I ------- v l` — J5'G.L.F W/Barbed re P x 01 I — i I I TOTAL PROJECT AREA=1.83 ACRES (CAMELOT PS S =0.60 ACRES do CAMELOT WWR SITE=1.23 ACRES) II I R/P(t) CI I . -11.11.1 monini mum Waft MOM Maw 111111.. W&A1 (Zea!, 41kT 111111.. Mien [___________ WHITMAN, REQUARDT AND ASSOCIATES, LLP Engineers, Architects and Planners 9030 Stony Point Parkway, Suite 220 (804) 272-8700 Richmond, Virginia FX: 2728897 wwwA .wra-ttp.corn ALBEMARLE COUNTY SERVICE AUTHORITY CAMELOT PUMP STATION SCALE FIGURE 2 0 40' 80' Attachment D Storm Sewer Design and Hydraulic Grade Line Computations ,11/23/2,009 VDOT FORM LD-229 - STORM SEWER DESIGN COMPUTATIONS PROJECT: NORTH FORK REGIONAL PUMP STATION PROJECT NFRPS PROPOSED CONDITIONS BASED ON 10-YEAR DESIGN FLOW MANNING'S "n"=0.013(ALL RCP PIPE) DRAIN. RUN- INLET RAIN- RUN- PIPE FROM TO AREA OFF CA TIME FALL OFF INVERT ELEVATIONS LENGTH SLOPE DIA. CAPACITY VELOCITY FLOW TIME MINUTES LINK POINT POINT COEF. • I Q REMARKS NO. ACRES C INCRE- ACCUM- MIN. IN/HR CFS UPPER LOWER FT. FT./FT. IN. C.F.S. F.P.S. INC. ACCUM. MENT ULATED • END END 1 END 2 2.760 0.75 2.070 2.070 11.0 5.18 10.72 392.40 390.00 56.0 0.0429 18 21.8 12.23 0.08 11.08 OK 3 2 4 0.000 0.00 0.000 2.070 11.1 5.16 10.69 389.10 389.00 20.4 0.0049 18 7.4 6.05 0.06 11.13 CHECK H.G.L. N:\46466-002\Engineering\HYDRO\STORM DRAIN-VDOT LD-229.xls 1 OF 1 Whitman, Requardt&Associa - LLP ( i 11/23/2009 LD-347 -HYDRAULIC GRADE LINE PROJECT: NORTH FORK REGIONAL PUMP ST ATION PROJECT 10-YEAR DESIGN FLOW (VELOCITIES BASED ON PARTIAL PIPE FLOW AS APPLICABLE) JUNCTION LOSS PIPE INLET OUTLET Do Qo Lo Sf o Hf ViA2 FINAL INLET RIM SUR- LINK# NUMBER W.S.EL. Vo Ho Qi Vi Qi x Vi ------ Hi ANGLE Hbend Ht 1.3Ht 0.5Ht H W.S.EL. ELEV. CHARGE COMMENTS 2q FT. IN. C.F.S. FT. % FT. F.P.S. FT. C.F.S. F.P.S. FT. FT. DEG. ▪ FT. FT. FT. FT. FT. FT. FT. FT. 3 3 390.20 18 10.7 20.4 1.104% 0.225 7.14 0.198 10.72 7.071 75.768 0.776 0.272 28 • 0.185 0.654 NA NA 0.88 391.08 392.95 NONE OK 1 1 391.20 18 10.7 56.0 1.110% 0.622 7.16 0.239 0.00 0.000 0.000 0.000 0.000 0 0.000 0.239 0.239 NA i 0.93 392.13 393.90 NONE OK • N:\46466-002\Engineering\HYDRO\HGL-VDOT LD-347.xls 1 OF 1 Attachment E Open Channel Flow Computations for MS-19 Analysis , Worksheet for Trapezoidal Channel STA 0+00 Project Description Friction Method Manning Formula Solve For Normal Depth Input Data - Roughness Coefficient 0.033 Channel Slope 0.00500 ft/ft Left Side Slope 0.04 ft/ft Right Side Slope 0.23 ft/ft Bottom Width 4.50 ft Discharge 10.72 ft3/s Results = Normal Depth 0.55 ft Flow Area 6.97 ft2 Wetted Perimeter 20.80 ft Hydraulic Radius 0.34 ft Top Width 20.72 ft Critical Depth 0.38 ft Critical Slope 0.02549 ft/ft Velocity 1.54 ft/s Velocity Head 0.04 ft Specific Energy 0.59 ft Froude Number 0.47 Flow Type Subcritical ,GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output.Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 0.55 ft Critical Depth 0.38 ft Channel Slope 0.00500 ft/ft Bentley Systems,Inc. Haestad Methods Solution Center Bentley FlowMaster [08.11.00.03] 11/23/2009 10:22:46 AM 27 Siemons Company Drive Suite 200 W Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 2 Worksheet for Trapezoidal Channel - STA 0+00 GVF Output Data , Critical Slope 0.02549 ftft Bentley Systems,Inc. Haestad Methods Solution Center Bentley FlowMaster [08.11.00.031 11/23/2009 10:22:46 AM 27 Siemons Company Drive Suite 200 W Watertown,CT 06795 USA +1-203-755-1666 Page 2 of 2 Worksheet for Triangular Channel - STA 0+16 Project Description Friction Method Manning Formula Solve For Normal Depth Input-Data Roughness Coefficient 0.045 Channel Slope 0.04650 ft/ft Left Side Slope 0.06 ft/ft Right Side Slope 0.04 ft/ft Discharge 10.72 ft3/s Results Normal Depth 0.44 ft Flow Area 4.15 ft2 Wetted Perimeter 19.01 ft Hydraulic Radius 0.22 ft Top Width 18.99 ft Critical Depth 0.43 ft Critical Slope 0.04923 ft/ft Velocity 2.58 ft/s Velocity Head 0.10 ft Specific Energy 0.54 ft Froude Number 0.97 Flow Type Subcritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 0.44 ft Critical Depth 0.43 ft Channel Slope 0.04650 ft/ft Critical Slope 0.04923 ft/ft Bentley Systems,Inc. Haestad Methods Solution Center Bentley FlowMaster [08.11.00.03] 11123/2009 10:22:03 AM 27 Siemons Company Drive Suite 200 W Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1