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Home My WebLink About18 Development Permit 371 Valley Veterinary Clinic IMPDATE: TO: ATTN: 5/26/95 McCLURE ENGINEERING, INC. 1722 Broadmoor, Suite 210 Bryan, Texas 77802 (409) 776-6700 FAX 776-6699 TRANSMITTAL LETTER Mrs. Veronica Morgan, P.E. Assistant City Engineer CITY OF COLLEGE STATION ATTACHED PLEASE FIND: }-· -~ /\Jt w\1i-V the Final Drainage Analysis .for Two (2) additional copies of the Valley Vet Clinic to be stamped with the City's aP6'~oval for our files (please call when they are ready) THANX! THESE ARE TRANSMITTED TO YOU FOR THE FOLLOWING REASON: _xx For Approval Your Use Revisions Made As Requested For Review and Comment Returned after Loan to Us RECEIVED BY: DATE: SIGNED BY: MICHAEL R. McCLURE, P.E., R.P.L.S. l/ervn1~, p/C4~ a~'>•'2j~ thisc. p/4n~ ~ f"1e affH'pnak 1'n~~. • McCLURE ENGINEERING, INC.---------- May 18, 1995 Mrs. Veronica Morgan, P.E. Assistant City Engineer CITY OF COLLEGE STATION P.O. Box 9960 College Station, Texas 77842 RE: VALLEY VETERINARY CLINIC IMPROVEMENTS FINAL DRAINAGE ANALYSIS Dear Veronica: Attached please find one ( 1) copy of the Final Drainage Analysis for the proposed building addition proposed to the VALLEY VETERINARY CLINIC located at 1841 Graham Road for your review and approval. This report is submitted in association with the Site and Building Plans to be submitted by the architect, Mr. Charlie Burris under separate cover to the Building Inspection Department. Should you have any questions please advise. ~;~ M~hael R. McClure, P.E., R.P.L.S. MRM/mlm attachments 1722 Broadmoor, Suite 210 • Bryan , Texas 77802 • (409) 776-6700 • FAX (409) 776-6699 FINAL DRAINAGE ANALYSIS FOR VALLEY VETERINARY CLINIC IMPROVEMENTS COLLEGE STATION , BRAZOS COUNTY , TEXAS MAY, 1995 PREPARED BY: McCLURE ENGINEERING, INC . 1722 Broadmoor , Suite 210 Bryan , Texas 77802 (409) 776-6700 CERTIFICATION I, Michael R. McClure, Registered Professional Engineer No. 32740, State of Texas, certify that this report for ·the drainage design of the VALLEY VETERINARY CLINIC improvements, was prepared by me in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof. _,,,,,,,, ---1\~ OF/~\' -~ \>' ••••••••• ... ~ ....... ,#'d:>'.··· * ···.'ISi • '* ... ··. *\ i!*: .. *l ~···································.e: ~ .. Ml.9.~.~.~.~.R~.¥.99hV.BE.~ 'L-()• 0 •4;"r.: ,1-:P0\~ 3274 0 /4Jj 01 A',,,:.f.q IS TE~ ~··0" ~-"" ''''Ss ···•···· ~ -\\ 10NAL ~ :'\,~ ....... ,,,, ..... ~/ INTRODUCTION GENERAL LOCATION TABLE OF CONTENTS DESCRIPTION OF DRAINAGE BASIN DRAINAGE DESIGN ANALYSIS CONCLUSION EXHIBITS RUNOFF COMPUTATIONS COMPOSITE RUNOFF COEFFICIENT CALCULATIONS CHANNEL ANALYSIS -· DRAINAGE AREA "A" CHANNEL ANALYSIS -DRAINAGE AREA "B" PIPE CULVERT ANALYSIS -WINSLOW S. DRIVEWAY PIPE CULVERT ANALYSIS -WINSLOW N. DRIVEWAY DRAINAGE AREA MAP Page No. 1 1 1 2 3 A-1 A-2 B-1 B-2 C-1 C-2 D INTRODUCTION FINAL DRAINAGE REPORT VALLEY VETERINARY CLINIC This final drainage report was prepared to document the impact to the existing drainage system from a proposed 600 square foot addition to the VALLEY VETERINARY CLINIC at 1841 Graham Road in College Station, Texas. GENERAL LOCATION The project is located on a 0.517 acre tract fronting Graham Road and situated approximately 450 feet in a southwesterly direction from the Graham Road/State Highway No. 6 Frontage Road intersection. The site is bounded by undeveloped properties on the southwest and the northwest sides. The Jack Winslow Body Shop is adjacent to the northeast boundary line. DESCRIPTION OF DRAINAGE BASIN Surf ace drainage is sheet flow and is generally in a southeasterly direction into the northwest ditch line on Graham Road. Flow in the ditch line continues in a northeasterly direction and merges with the southwest ditch line flow along State Highway 6. At approximately 900 feet southeast of the Graham Road/State Highway 6 intersection, the ditch line flow outfalls into the primary drainage system at the North Fork of Lick Creek. The watershed consists primarily of fine sandy loam topsoil supporting native grasses and a minor amount of scrubby growth hardwood trees. The soils percolate slowly and are characterized by severe seasonal shrink-swell volume changes. The drainage area predominantly slopes between 2.5% to 5%. Offsite drainage flow patterns will not be altered as a result of the proposed improvements. All storm water will continue to enter the existing ditch line on Graham Road. DRAINAGE DESIGN ANALYSIS Since there is a very small increase in impervious cover at the site and no new culverts are proposed, this drainage analysis will consist simply of calculating the peak runoff and analyzing the existing infrastructure downstream of the site. Peak runoff from the site is determined for predevelopment and post-development conditions for the 25-year storm interval. Since the drainage areas are less than 50 acres, the Rational Method is used (see Exhibit "A-1"). See Exhibit "A-2" for calculation of composite runoff coefficients. See Exhibits "B-1", "B-2, "C-1" and "C-2" for the pipe culvert analysis and drainage ditch capacities for the tow driveway culverts at the entrance to the Jack Winslow property. From these calculations, it has been demonstrated that the existing ditch line capacities and downstream culverts in the immediate vicinity of the project are adequate for the 25-year storm event. Since there is no change in the peak runoff, Pre/Post Conditions for Drainage Area "C", no further calculations have been made downstream. 2 CONCLUSION This proposed building addition should be permitted since there is adequate capacity within the drainage structures on Graham Road. It has been demonstrated that the project has no adverse effect on the downstream conditions. The 100-year storm discharges will be contained within the Graham Road and State Highway No. 6 right-of- way. 3 RUNOFF COMPUTATION ACRES -DRAINED TIME OF CONCENTRATION DISCHARGE DRAINAGE AREA Co~P0'$1 Tc= 1l9e-GRAVEL RESIDENTIAi COMM. PAVEMENT TOTAL L v tc TIME 15 a5 125 a25 NO. AREA c-5 E E C= C= ·C= C= CA -61iL.cW fl (p~~1 Z.41 (). 4.% /.o n r, oo /. e;; ~.1 10 q,70 /O ,(p A (Pos-r) 2..4-J o.4 t,4 I . (/ ei (,oo 1.s (,.{ /O q .10 10 .8 B ·z.-z 3 (),So~ /,13 5 7so (. '3 q,r,. 10 Cf .70 11. o c_ 3 3 .53 o .4 S 15 .0 "1 Z5 BD (. '2. 3 5 .5 3 '5.~ 5,/0 77 .0 AU, (Pie) ?~.1 1 0 .4-~4. 17.~3 zc;go I. z..-'?~.a' ~$'.&' 5 ./0 86.4- fl fJ C. ( Pffif) 38.1 7 (). 454-(1.33 i sBo /.'l.. '35'.e 35'.8 s .10 88.4- f/B (PU:) 4,t,4. 0,451 ·z.z3z.. Blc J.4 /o.4 to.4-q.(p~ 2,/,(p I A& (fo-;,T) 4..t,4-DA~& 2. Z:SS B10 1.4-l b .4-10 :4-'l.l.6 Z./.~ ' .\ EXHIBIT "A-1 " ·- EXHIBIT "A-2" COMPOSITE RUNOFF COEFFICIENT CALCULATIONS DRAINAGE AREA "A" PREDEVELOPMENT CONDITION: C = C . A . + C2 lk A = 10.425(.95) + 94,555(.40) 104,980 = 0.455 DRAINAGE AREA "A" POST-DEVELOPMENT CONDITION: c = 12.252(.95) + 92.728(.40) 104,980 = 0.464 DRAINAGE AREA "B" PRE/POST DEVELOPMENT CONDITIONS: c = 19.200(.95) + 77.939(.40) 97,139 = 0.509 DRAINAGE AREA "AB" PREDEVELOPMENT CONDITION: c = 104.980(.455) + 97.139(.509) 202,119 = 0.481 DRAINAGE AREA "AB" POST-DEVELOPMENT CONDITION: c = 104.980(.464) + 97.139(.509) 202,119 = 0.486 EXHIBIT ''B-l" TRAPEZOIDAL CHANNEL ANALYSIS NOR"AL DEPTH CO"PUTATION "ay 18, 1995 VALLEY VET CLINIC SITE I"PROVE"ENTS 6RAHA" RD. DITCH CAPACITY CALCULATED DOWNSTREA" or DRAINAGE AREA 1 A1 ==================================================================== PROGRA" INPUT DATA: DESCRIPTION Flow Rate !cubic feet per secondl •••••••.•..•••••••••••. Channel Botto• Slope (feet per foot) .................. .. "anning 's Roughness Coefficient In-value I .............. . Channel Side Slope -Left Side Chorizontal/verticall •••• Channel Side Slope -Right Side Chorizontal/verticall ••• Channel Botto• Width (feet),,,,,,,,,,,,,,,,,,,,,,,,,,,,, VALUE 10.8 0.0025 0.0300 3.00 3.00 0.1 ==================================================================== PROGRA" RESULTS: DESCRIPTION VALUE Nor1al Depth Cfeetl..................................... 1.37 Flow Velocity (feet per second)......................... 1.87 Froude Nu1ber CFlow is Sub-Critical).................... 0.396 Velocity Head Cfeetl........ ..••. ........ ... .. .. •. ..•... 0.05 Energy Head I feet I...................................... 1. 42 Cross-Sectional Area of Flow !square feetl.............. 5.77 Top Width of Flow Cfeetl... .............. ... .. .. .. .. .... 8.32 ==================================================================== TRAPEZOIDAL CHANNEL ANALYSIS CO"PUTER PROGRA", Version 1.3 Ccl 1986 Dodson~ Associates, Inc., 7015 W. Tidwell, 1107, Houston, TX 77092 17131 895-8322. A 1anual with equations ~ flow chart is available. EXHIBrr "B-2" TRAPEZOIDAL CHANNEL ANALYSIS NOR"AL DEPTH CO"PUTATION "ay 18, 1995 VALLEY VET CLINIC SITE I"PROVE"ENTS GRAHA" RD. DITCH CAPACITY CALCULATED DOWNSTREA" OF DRAINAGE AREA 1 B1 ==================================================================== PROGRA" INPUT DATA: DESCRIPTION Flow Rate (cubic feet per second) •.••••••.•••..•.•.•••.. Channel Botto• Slope (feet per foot> .................. .. "anning's Roughness Coefficient Cn-valueJ .•.•.....•••••• Channel Side Slope -Left Side <horizontal/vertical) •... Channel Side Slope -Right Side (horizontal/vertical) .•. Channel Botto• Width (feet> ............................ . VALUE 21. 8 0.0100 0.0300 3.00 3.00 0.1 ==================================================================== PROGRA" RESULTS: DESCRIPTION VALUE Nor1al Depth (feet)..................................... 1.38 Flow Velocity (feet per second)......................... 3.75 Froude Nuaber <Flow is Sub-Critical).................... 0.793 Velocity Head (feet).................................... 0.22 Energy Head <feet l...................................... 1. 59 Cross-Sectional Area of Flow (square feet).............. 5.81 Top Width of Flow <feet>................................ 8.35 ==================================================================== TRAPEZOIDAL CHANNEL ANALYSIS CO"PUTER PROGRA", Version 1.3 Ccl 1986 Dodson ~ Associates, Inc., 7015 W. Tidwell, 1107, Houston, TX 77092 1713) 895-8322. A 1anual with equations ~ flow chart is available. EXHIBrr "C-1 " PIPE CULVERT ANALYSIS CO"PUTATION or CULVERT PERFOR"ANCE CURVE "ay 18, 1995 VALLEY VET CLINIC SITE I"PROVE"ENTS S. DRIVEWAY ENTRANCE INTO JACK WINSLOW BODY SHOP ==================================================================== PROGRA" INPUT DATA: DESCRIPTION Culvert Dia1eter (feetl ................................ . fHWA Chart Nu1ber Cl,2 or 3) .•..•••...•••••••••••••••••• Scale Nu1ber on Chart <Type of Culvert Entrance) •••..••• "anning's Roughness Coefficient Cn-valuel ••.•••••••...•• Entrance Loss Coefficient of Culvert Opening •••••••...•• Culvert Length (feetl. ................................. . Culvert Slope (feet per foot) ..•.••••••••..••••.•••••••• VALUE 2.00 2 3 0.0240 0.50 30.0 0.0010 ==================================================================== PROGRA" RESULTS: flow Tailwater Headwater lftl Nor1al Critical Depth at Outlet Rate Depth Inlet Outlet Depth Depth Outlet Velocity (cfsl lftl Control Control lftl (ft) lftl lfpsl 10.B 1.37 1.92 2.07 2.00 1.18 1. 37 4.71 ==================================================================== PIPE CULVERT ANALYSIS CO"PUTER PROGRA" Version 1.7 Copyright Ccl1986 Dodson ~ Associates, Inc., 7015 W. Tidwell, 1107, Houston, TX 77092 1713) 895-8322. All Rights Reserved. • EXHIBIT "C-2" PIPE CULVERT ANALYSIS COKPUTATION OF CULVERT PERFORKANCE CURVE Kay 18, 1995 VALLEY VET CLINIC SITE IKPROVEKENTS N. DRIVEWAY ENTRANCE INTO JACK WINSLOW BODY SHOP ==================================================================== PROGRAK INPUT DATA: DESCRIPTION Culvert Dia1eter (feet) ................................ . FHWA Chart Nu1ber (1,2 or 3) ..•••.••.••••••••••.••••••.. Scale Nu1ber on Chart (Type of Culvert Entrance) •.••••.• Kanning 1s Roughness Coefficient (n-value) •••••••••••••.. Entrance Loss Coefficient of Culvert Opening ••••••..•••. Culvert Length (feet) .••..•••••••••••••••••••••••.••..•• Culvert Slope (feet per foot) ••••.•••.••••••••••••.••.•• VALUE 2.00 2 3 0.0240 0.50 30.0 0.0067 ==================================================================== PROGRAK RESULTS: Flov Tailvater Headvater (ft) Nor1al Critical Depth at Outlet Rate Depth Inlet Outlet Depth Depth Outlet Velocity (cfs) (ft) Control Control Cftl (ftl (ftl (fpsl 21.8 1.38 3.74 3.70 2.00 1.67 2.00 6.94 ==================================================================== PIPE CULVERT ANALYSIS COKPUTER PROGRAM Version 1.7 Copyright Ccl1986 Dodson~ Associates, Inc., 7015 W. Tidvell, 1107, Houston, TX 77092 C713l 895-8322. All Rights Reserved.