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HomeMy WebLinkAbout51 Development Permit 411 Shenandoah Phase IISHENANDOAH PHASTS TWO THRU FIVE FINAL DRAINAGE ANALYSIS City of COLLEGE STATION BRAZOS COUNTY, TEXAS APRIL, 1996 Prepared By: McClure Engineering, Inc. 1722 Broadmoor Drive, Suite 210 Bryon, Texas 77802 OAH SHEN AND PHASES TWO 73 7HRU FIVE FINAL DRAINAGE ANALYSIS City of COLLEGE STA Tl BRAZOS COUNTY, ON TEXAS APRIL, 1996 Prepared By: Inc. uite 210 McClure Engineering, 1722 Broadmoor Drive, S Bry:::m, Texas 7780 '2 . ,.._ CERTIFICATION I , Michael R. McClure, Registered Professional Engineer No. 32740, State of Texas, certify that this report for the drainage design of SHENANDOAH, PHASES TWO THRU FIVE, was prepared by me in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof ... TABLE OF CONTENTS PAGE NO. INTRODUCTION 1 PRIMARY DRAINAGE BASIN DESCRIPTION 1 GENERAL CONCEPT 2 TABLE A 4 TABLEB 4 SPECIAL ITEMS 4 CONCLUSION 5 INDEX OF EXHIBITS: MASTER DRAINAGE MAP "A" SCS TYPE II STORM ROUTING (HEC-1) "B-1" RATIONAL/TRIANGULAR HYDROGRAPH ROUTING (HEC-1) ''B-2" RATIONAL FORMULA DRAINAGE AREA CALCULATIONS "C-1" INLET & PIPE SIZE CALCULATIONS "C-2" EXCERPT FROM FEMA MAP "D" TRAPEZOIDAL CHANNEL ANALYSIS ( 100-Year Overflow @ Windfree culdesac) TRAPEZOIDAL CHANNEL ANALYSIS ( 100-Year Overflow @ Tiffany Knuckle) "E" "F" FINAL DRAINAGE ANALYSIS FOR SHENANDOAH PHASES TWO Thru FIVE INTRODUCTION: In keeping with the drainage plan submittal requirements of the City of College Station Storm Water Management Plan, this drainage analysis is prepared to demonstrate that the proposed subdivision is planned within the guidelines of the Storm Water Management Ordinance. The study includes the drainage analysis for the storm water detention requirements of Phases Two through Five of the SHENANDOAH development. PRIMARY DRAINAGE BASIN DESCRIPTION: The proposed site is located in the southern portion of College Station along the southeast line of Barron Road and approximately 500 feet from State Highway Six. The site is contiguous to the SHENANDOAH PHASE ONE subdivision to the southeast. To the northeast of the site are several small parcels in various stages of development. Northwest of ~his site is an undeveloped tract . . :.., .. The site is sparsely wooded with 1 % to 5% slopes. Some grading has been conducted on the site with development of the SHENANDOAH PHASE ONE subdivision in 1983. No offsite storm water flo~ to or across this site. According to the Flood Insurance Rate Maps for Brazos County, Texas and Incorporated Areas, Map Number 48041 C0205 C, effective July 2, 1992, the project site is not located in a 100-year flood hazard area The site drains into two major tributaries of Carter's Creek. The northern portion of the site drains to the north into the Barron Road right-of-way through existing drainage structures and subsequently into the South Fork of Lick Creek. The smaller southern portion of the site drains to the south into Tiffany Trail, Windfree Drive, Hunter Creek Drive, Decatur Drive, and Stony Creek Lane. This storm water runoff enters the existing storm drain system in SHENANDOAH PHASE ONE. The increase in runoff coefficient of this area is offset by a minor alteration in the drainage divides to force as much flow as possible to the north into the proposed detention ponds in Phases Two and Four. GENERAL CONCEPT: The flows will be divided as shown on the attached Drainage Plan (See Exhibit "A", Master Drainage Map). The areas flowing to the existing SHENANDOAH PHASE ONE subdivision are altered to eliminate the impact of this new development on the existing system. The existing system was built with the intent of providing drainage outlets for this area, but is inadequate for this purpose. With the improvements of Phase One, no storm drains were left accessible and all flows entering the existing SHENANDOAH PHASE ONE area must be overland sheet and gutter flows. Gutter capacity in existing streets was designed to handle a five year storm and is substantially below our current standards. These facts limit the amount of flow which can be allowed toward this direction. Because of these conditions, the drainage divides are shifted to minimize the amount of storm water which flows into the existing SHENANDOAH infrastructure. Flows to the north will be intercepted by the proposed streets designed with grades adequate to convey the flows to a storm drain system (see Exhibits "C-1" and "C-2"). The system is generally designed to convey the ten year storm underground and the 100 year storm within the rights-of-way and easements to the two proposed detention ponds. See Exhibits "E" and "F" for overflow -2 - calculations at low point inlets. The proposed ponds are sized to detain (post development flow </= predevelopment flow) for the two , five, ten, twenty-five , fifty, and one hundred year storms. See Table "A" for peak flow summary data at the study point A, the 18" RCP Culvert at the Wilson Plumbing Driveway and see Table "B" for peak flow summary data at study point B, the existing junction box at the intersection of Dove Trail and Barron Road. Note that the peak discharges for each storm event has been reduced or matched at the stud y points. The detention pond built with Phase Two greatly over-detains storm flows. This plan was adopted in order to alleviate an existing restriction (the severely undersized 18" RCP culvert at Wilson Plumbing driveway), which is the limiting factor in the design of this drainage system. This culvert at the driveway crossing of the Barron Road ditch line accommodates less than the existing two-year storm. As an indication of how undersized this culvert is, the culvert immediately downstream of this one (with a nearly identical flow) is a 27" RCP (46% more area). The detention pond designed with Phase Four outfalls into an adequately designed 30" RCP built with the construction ofOakgrove Subdivision. Please note that the capacity of the outfall is 46.5 cfs flowing full. The SCS type II storm Hydrograph indicates a post-development peak flow of 62 cfs for the 10 year storm and the rational/triangular Hydrograph analysis indicates a post-development peak flow . : ... · .. of 38 cfs. Theoretically, both techniques are conservative. Both ponds will have excellent access from Barron Road and are designed with low maintenance outlet structures, concrete pipe and a minimum 6' wide berm with 4: 1 side slopes. The ponds as designed will have roughly .5' of free board for the 100 year storm. The HEC-1 computer printout in Exhibit "B-1" updates the model for the entire subdivision for the various SCS Type II storm events. Exhibit "B-2" has been prepared to document the -3 - functionality of the Phase Four pond using peak flows obtained from the Rational Method and a Triangular Hydrograph routing of the pond .. The data is consistent with the "DRAINAGE REPORT ADDENDUM FOR SHENANDOAH, PHASE THREE" dated January 2, 1996. TABLE A Peak Flow Data @ Study Point "A" (Wilson Plumbing Driveway) STORM PRE-DEV. FLOW POST-DEV. FLOW (YEAR) (CFS) (CFS) 2 27 18 5 46 24 10 61 27 25 78 31 50 90 34 100 105 50 TABLEB Peak Flow Data @ Study Point "B" (Proposed Junction Box @ Dove TraiUBarron Road Intersection STORM SCS TYPE Il STORM (cfs) RATIONAL\TRIANGULAR (cfs) (YEAR) POST-DEV. PRE-DEV.(cfs) POST-DEV.(cfs 2 33 31 24 5 44 38 27 10 50 43 29 25 86 49 31 50 108 56 33 100 127 63 35 SPECIAL ITEMS: Please note the substantial difference in the function of the pond. The outlet (existing 30" RCP built in Dove Trail) has a capacity of 46.5 cfs, which is halfway between the results of the -4- two routing techniques. Because the SCS method has substantially more volume in the computed Hydrograph, we generally use this method in designing detention ponds. However, both methods are acceptable under the current drainage ordinance. Based on the result of the Triangular Hydrograph routing , we have shown that the outfall has adequate capacity and is in compliance with the Drainage Ordinance. Based on the SCS Type II storm routing, the detention pond has ample volume for this application. CONCLUSION: The drainage plan outlined above satisfies the requirements of the City of College Station Storm Water Management Plan. The proposed infrastructure has been properly sized and the peak discharge from the proposed development has been reduced or matched for the full range of storm events thereby lessening the impact on downstream property and infrastructure . . ·. -5- EXHIBIT B-1 SCS TYPE II STORM ROUTING ENTIRE SUBDIVISION 1 * •••••••••••••••••••••••••••• ******* *** •• FLOOD f!YDROGRAPH PACKAGE ( HEC-1 l HAY 1991 VERSION 4. 0. lE Lahey F77L-EM/32 version 5.01 Dodson ' A.3sociates , Inc. RUN DATE 04/09/96 TIME 10:10:27 x x xxxxxxx x x x x x x xxxxxxx xx xx x x x x x x x x xxxxxxx xxxxx x x xx x x x xxxxx x x x x x x xxxxx xxx U.S . ARMY CORPS OF ENGINEERS f!YDROLOGIC ENGINEERING CENTER 609 SECOND STREET DAVIS, CALIFORNIA 95616 (916) 551-1748 THIS PROGRAM REPLACES ALL PREVIOUS VERSIONS OF HEC-1 KNOWN AS HECl (JAN 73), HEClGS, HEClDB, AND HEClKW. THE DEFINITIONS OF VARIABLES -RTIMP -AND -RT IOR-HAVE CHANG ED FROM THOSE USED WITH THE 1973-STYLE INPUT STRUCTURE. THE DEFINITION OF -AMSKK-ON RM-CARD WAS CHANGED WITH REVISIONS DATED 28 SEP 81. THIS IS THE FORTRAN?? VERSION NEW OPTIONS : DAMBREAK OUTFLOW SUBMERGENCE , SINGLE EVENT DAMAGE CALCULATION, DSS:WRITE STAGE FREQUENCY, DSS:READ TIME SERIES AT DESIRED CALCULATION INTERVAL LOSS RATE:GREEN AND AMPT INFILTRATION KINEMATIC WAVE: NEW FINITE DIFFERENCE ALGORITHM HEC-1 INPUT PAGE LINE ID ....... 1. ...... 2 ....... 3 ....... 4 ....... 5 ....... 6 ....... 7 ...••.• 8 •. · .•... 9 ..•... 10 ID EXIST SHENANDOAH IT 3 01AOG94 0000 480 IO 5 0 0 JP 5 JR PREC 11 9. 8 8.8 7.4 6. 2 4.5 6 KK LICK 7 KM Pl= EX P2•PROP . 8 BA .0305 9 PB 10 IN 30 01AUG94 0000 11 PC .0053 . 0108 . 0164 .0223 .028 4 . 0347 . 0414 • 0483 .0555 .0632 12 PC .0712 . 0797 . 0887 . 0984 .1089 .1203 .1328 .1467 .1625 .1808 13 PC .2042 .2351 .2833 . 6632 .7351 . 7724 .7989 • 8197 .8380 .8538 14 PC . 8676 .8801 .8914 • 9019 • 9115 . 9206 .9291 .9371 .9446 .951 9 15 PC . 9588 . 9653 . 9717 • 9777 .9836 .9892 . 9947 1.000 16 LS 0 75 0 17 UD .37 18 KP 2 19 LS 0 20 UD . .37 . 21 KK PROP 22 BA .02 47 23 LS 0 24 UD .27 25 KP 2 26 LS 0 84 ~27 UD .27 28 KK COMB 29 HC 2 30 KK POND PROP DETENTION POND 31 RN 32 KP 33 RS FLOW -1 34 SA 0 . 248 • 681 1. 037 1.239 1. 327 1. 413 35 SE 283 284 2 85 286 2 87 288 289 36 SL 283 1. 227 • 7 . 5 37 SS 288 20 1. 5 38 KK BYPASS 39 BA .0061 40 LS 0 41 UD . 51 42 KP 2 43 LS 84 0 44 UD .39 LINE ID ....... L ...... 2 ....... 3 ....... 4 ....... 5 ....... 6 ....... 7 ....... 8 ...•... 9 ...... 10 45 46 47 48 49 50 51 52 53 KK HC KK BA LS UD KP LS UD KK RN KP RS BARRON 2 Area • 02609 0 .154 .11 DECATUR DA's 1-11 75 83 DETENTION POND FLOW -1 54 55 5 6 5 7 5 8 59 6 0 6 1 6 2 SA . 00 4 6 .1525 . 2579 . 29 75 . 3401 63 6 4 65 66 67 6 8 69 SE S L KM S S KK BA LS UD KP LS UD 2 9 0. 65 2 91.6 . 7 2 96 .5 Area34 . 00456 0 .154 2 .154 291 292 293 3 .1 4 1 5 .9 . 5 IS STD. 30 LS DA 's 34 • 35 78 80 7 0 7 1 KK Dove COMBINE FLOW S AT PO ND 72 73 74 HC KK HC zz 2 To tal 2 1••······································· . FLOOD HYDROGRAPH PACKAGE (llEC-1) MAY 1991 VERSION 4.0. lE Lahey F77L-EM /32 version 5. 01 Dodson & Associates, Inc. RUN DATE 04/09/96 TIME 10:10:27 EXIST SHENANDOAH 3 IO OUTPUT CONTROL VARIABLES IPRNT 5 PRINT CONTROL I PLOT 0 PLOT CONTROL QSCAL 0. HYDROGRAPH PLOT SCALE IT HYDROGRAPH TIME DATA NMIN 3 MINUTES IN COMPUTATION !DATE 1AUG94 START ING DATE !TIME 0000 STARTING TIME 29 4 295 INTERVAL NQ 480 NUMBER OF HYDROGRAPH ORDINATES JP JR NDDATE 1AUG94 ENDING DATE NDTIME 2357 ENDING TIME I CENT 19 CENTURY MARK COMPUTATION INTERVAL 0. 05 HOURS TOTAL TIME BASE 23 . 95 HOURS ENGLISH UNITS DRAINAGE AREA PRECIPITATION DEPTH LENGTH, ELEVATION FLOW STORAGE VOLUME SURFACE AREA TEMPERATURE MULTI-PLAN OPTION NPLAN MULTI-RATIO OPTION SQUARE MILES INCHES FEET CUBIC FEET PER SECOND ACRE -FEET ACRES DEGREES FAHRENHEIT NUMBER OF PLAN S RATIOS OF PRECIPITATION 11 .00 9.80 8.80 7.40 6.2 0 4 .50 .3855 . 43 36 2 96 297 • 4 8 4 6 2 98 U.S. ARMY CORPS OF ENGINEERS HYDROLOGIC ENGINEERING CENTER 609 SECOND STREET DAVIS, CALIFORNIA 95616 (916) 551-1748 PEAK FLOW AND STAGE (END-OF-PERI OD ) SUMMARY FOR MULTIPLE PLAN -RATIO ECONOMI C COMPUTATION S FLOW S IN CUBI C FEET PER SECOND, AREA IN SQUARE MILES TIME TO PEAK IN HOURS RATIOS APPLIED TO PRECIPI TATI ON OPERATION STATION AREA PLAN RATIO l RATIO 2 RATIO 3 RATIO 4 RATIO 5 RATIO 6 11.00 9 .80 8.80 7.40 6.20 4. 50 HYDROGRAPH AT LICK 0.03 FLOW 105. 90. 78. 61. 46. 27. TIME 11. 70 11. 70 11 . 70 11 . 70 11.70 11. 70 FLOW 0. o. 0. 0. o . 0. TIME 0. 05 0.05 0.05 0.05 0.05 0.05 HYDROGRAPH AT + PROP 0. 02 FLOW 0. o . 0. 0. 0 . 0. TIME 0.05 0. 05 0.05 0 .05 0.05 0.05 FLOW 107. 94. 83. 67 . 54. 35. TIME 11 .60 11. 60 11. 60 11. 60 11. 60 11. 60 2 COMBINED AT COMB 0.06 FLOW 105. 90. 78. 61. 46. 27. TIME 11. 70 11. 70 11. 70 11. 70 11. 70 11.70 FLOW 107 . 94. 83. 67. 54. 35. TIME 11.60 11 . 60 11.60 11. 60 11. 60 11. 60 ROUTED TO POND 0.06 FLOW 105 . 90. 78. 61. 46 . 27. TIME 11. 70 11. 70 11. 70 11. 70 11 .70 11. 70 FLOW 35. 22 . 15. 14 . 13. 11. TIME 12 .10 12. 25 1 2.35 1 2 .30 12.25 12 .10 PEAK STAGES IN FEET STAGE 0.00 0. 00 0.00 0.00 o. 00 0.00 TIME 0.00 0.00 0.00 0.00 0. 00 0.00 STAGE 288.47 288 .21 287. 82. 287 .15 286.55 285. 65 TIME 12.10 12. 25 12.40 12.30 12.25 12 .15 HYDROGRAPH AT BYPASS 0 . 01 FLOW o. 0. 0. 0. 0. 0. TIME 0.05 0.05 0.05 0.05 0.05 0.05 FLOW 23. 20. 18. 14. 11. 7. TIME 11. 70 11. 70 11. 70 11. 70 11 . 70 11. 70 2 COMBINED AT BARRON 0.06 FLOW 105. 90. 78. 61. 46. 27. TIME 11 . 70 11. 7 0 11. 70 11. 70 11. 70 11. 70 FLOW 50. 34. 31. 27. 24 . 18 . TIME 12.00 11. 70 11. 75 11. 75 11 . 75 11. 75 HYDROGRAPH AT Area 1 0.03 FLOW 115. 99 . 86 . 68 . 52. 31. TIME 11. 50 11. 50 ll.S5 11 . 55 11. 55 ll.S5 FLOW 130. 114. 101. 82. 66. 43. TIME 11. 50 11.50 11. 50 11.50 11.50 11. 50 ROUTED TO + DECATU 0. 03 FLOW 115. 99. 86. 68. 52. 31. TIME 11. 50 11 .SO ll.5S 11. 55 11. 55 11.55 FLOW 127. 108. 86 . 50. 44 . 33. TIME ll .5S 11. 55 11. 60 11. 65 11. 60 11. 60 PEAK STAGES IN FEET STAGE o. 00 0.00 0.00 0.00 0.00 0.00 TIME 0 . 00 0.00 o.oo 0.00 0.00 0.00 STAGE 297. 36 297. 22 297.02 296.43 295.29 293. 69 TIME 11. 55 11. 55 11. 60 11. 65 11. 60 11. 60 HYDROGRAPH AT + Area34 c>. oo FLOW 21. 18. 16. 1 3. 10 . 6. TIME 11. 50 11. so 11. so ll.S5 11.55 11 . 55 FLOW 2 1. 19. 16. 13. 10. 7. TIME 11. 50 11. 50 11.SO 11 .so 11. 55 11. 55 COMBINED AT + Dove 0. 03 FLOW 136 . 117. 102 . 80. 62. 38. TIME 11. 50 11. 50 11. 50 11.55 11 .55 11.55 FLOW 148. 127. 102. 62. 53. 39. TIME 11. 55 11. 55 11.55 11. 60 11. 60 11. 60 2 COMBINED AT Total 0 .09 FLOW 227. 196. 169. 1 33 . 102. 60. TIME 11. 55 11. 55 11. 55 11 . 55 11. 55 11. 55 FLOW 181. 157. 130. 87. 75. 55. TIME 11.55 11. 55 11 .60 11. 60 11. 60 11.60 *** NORMAL ENO OF HEC-1 ... EXHIBITB-2 RA TIONALffRIANGULAR HYDROGRAPH ROUTING (PHASE FOUR POND ONLY) i·························***********••••• * FLOOD HYDROGRAPH PACKAGE (HEC-11 HAY 1991 VERSION 4. 0 . lE Lahey F77L-EH/ 32 version 5. 01 Dodson & ~sociates, Inc. RUN DATE 04/09/96 TIME 09:13:59 x x x x x x xxxxxxx x x x x x x xxxxxxx xxxxx x x x x x xxxx x x x x x x xxxxxxx xxxxx x xx x xxxxx x x x xxx U.S . ARMY CORPS OF ENGINEERS HYDROLOGIC ENGINEERING CENTER 609 SECOND STREET DAVIS, CALIFORNIA 95616 (916) 551-1148 THIS PROGRAM REPLACES ALL PREVIOUS VERSIONS OF HEC-1 KNOWN AS HECl (JAN 73), HEClGS, HEClDB, AND HEClKW. THE DEFINITIONS OF VARIABLES -RTIMP-AND -RTIOR-HAVE CHANGED FROM THOSE USED WITH THE 1973-STYLE INPUT STRUCTURE. THE DEFINITION OF -AMSKK-ON RM-CARD WAS CHANGED WITH REVISIONS DATED 28 SEP 81 . THIS IS THE FORTRAN77 VERSION NEW OPTIONS: DAMBREAK OUTFLOW SUBMERGENCE , SINGLE EVENT DAMAGE CALCULATION, DSS:WRITE STAGE FREQUENCY, DSS:READ TIME SERIES AT DESIRED CALCULATION INTERVAL LOSS RATE:GREEN AND AMPT INFILTRATION KINEMAT IC WAVE: NEW FINITE DIFFERENCE ALGORITHM HEC-1 INPUT PAGE LINE ID ....... 1. ...... 2 ....... 3 ....... 4 ......• 5 ....... 6 .•....• 7 ....... 8 ..•.... 9 •..... 10 1 2 3 10 11 12 13 14 ID IT IO JR KK IN QI KK RS SA SE SL SS zz EXIST 1 5 FLOW Area 1 9 0 DECATUR 0 290 . 65 291. 6 296.5 SHENANDOAH 01JAN96 0 101. 3 DA's 01JAN96 1 DETENTION FLOW .0046 291 3.1415 15 1········································· FLOOD HYDROGRAPH PACKAGE (HEC-11 MAY 1991 VERSION 4 . 0. lE Lahey F77L-EM/32 version 5.01 Dodson & ~soc ia tes, Inc. RUN DATE 04/09/96 TIME 09:13:59 EX I ST SHENANDOAH 3 IO OUTPUT CONTROL VARIABLES 0000 100 0 90.1 79. 7 1-13 0000 . 5 .01 POND -1 .1525 .2579 292 293 . 7 .5 1.5 IPRNT 5 PRINT CONTROL I PLOT 0 PLOT CONTROL 69. 7 62 .1 .2975 .3401 294 295 QSCAL 0. HYDROGRAPH PLOT SCALE IT HYDROGRAPH TIME DATA NMIN MINUTES IN COMPUTATION INTERVAL !DATE 1JAN96 STARTING DATE I TIME 0000 STARTING TIME NO lo·o NUMBER OF HYDROGRAPH ORDINATES NDDATE 1JAN96 ENDING DATE NDTIME 0139 ENDING TIME 51. 0 .3855 . 4336 296 297 . 4846 298 U.S. ARMY CORPS OF ENGINEERS HYDROLOGIC ENGINEERING CENTER 609 SECOND STREET DAVIS, CALIFORNIA 95616 (916) 551-1748 JP JR COMPUTATION INTE RVAL TOTAL TIME BASE 0. 02 HOURS l.65 HOURS ENGLISH UNITS DRA INAGE AREA SQUARE MILES PRECIPITATION DEPTH INCHES LEN GTH, ELEVATION FEET FLOW CUBIC FEET PER SECOND STORAGE VOLUME ACRE-FEET SURFACE AREA ACRES TEMPERATURE DEGREES FAHRENHEIT MULTI-PLAN OPTION NP LAN MULTI-RATIO OPTION RATIOS OF RUNOFF NUMBER OF PLANS 101 .30 90.10 79.70 69.70 62 .1 0 51.00 PEAK FLOW AND STAGE (END-OF-PERIOD) SUMl1ARY FOR MULTIPLE PLAN -RATIO ECONOMIC COMPUTATIONS FLOWS IN CUBIC FEET PER SECOND , AREA IN SQUARE MILES TIME TO PEAK IN HOURS RATIOS APPLIED TO FLOW S OPERATION STATION AREA PLAN RATIO l RATIO 2 RATIO 3 RATIO 4 RATIO 5 RATIO 6 101. 30 90 .10 79 .70 69. 70 62 .10 51.00 HYDROGRAPH AT Ar ea 1 0 .00 FLOW 101. 90. 60. 70. 62. 51. TIME 0.15 0.15 0.15 0 .1 5 0 .15 0 .15 ROUTED TO DECATU 0 .00 FLOW 35 . 33. 31. 2 9. 27. 2 4 . TIME 0 .35 0. 33 0.33 0. 33 0 .32 0. 30 PEAK STAGES IN FEET STAGE 295 .52 295 .11 294.69 29 4. 29 293.96 293. 52 TIME 0. 35 0. 33 0 . 33 0 . 33 0.32 0. 30 *** NORMAL END OF HEC -1 *** ·. EXHIBIT C-1 Rational Formula Drainage Area Calculations Revised April, 1996 < UJ Cl :c ~ ~ a:: UJ ..J < < 0.. < < I-0 0 UJ UJ 0 i= UJ Cl (!) Cl ..J ..J ..J (!) a: ..J a: zZ z ..J LL LL < < UJ z < :5 ~ :5 ~ a: :c a: 0 ..J > UJ ..J UJ I-UJ I-0 z < UJ < ~~ ~ < a:: ~ a:: ~ ~ (!) ~ ..J I-~ 0 I-Cl UJ 0 I-UJ 0 UJ 0 0 UJ 0 LO 0 0 ::::> z ::::> ..J <U a: 0 z a:: UJ a: 0 > ..J > ..J (!) ~ (!) ~ r./) N l.O 0 ...... N l.O ...... Cl I-::::> < a:< a:: I-0 LL 0 LL u ::::> 0 0 !: 0 0 0 0 NO. AC. 0.4 0.5 0.87 CA . min mm cfs cf s In/Hr cfs cfs cfs cfs lA O.S9 0.00 O.S9 0.00 0.30 60 o.s 300 4.0 3.7 s.o 2.4 2.9 11. 0 3.2 3.7 4.2 4.7 lB 1. OS 0.00 1. OS 0.00 O.S3 llO 1. 3 300 4.0 4.6 s.o 4.3 S.2 11. 0 S.8 6.6 7. 4 8.3 2 0.94 0.00 0.94 o.oo 0.47 80 o.s 340 1. 8 6.3 6.3 3.6 4.3 10.2 4.8 s.s 6.2 6.9 3A 1. 77 0.00 1. 77 0.00 0.89 230 2.S 300 1.5 8.8 8.8 S.9 7.2 9.1 8.1 9.2 10.4 11. 7 3B 0.34 0.00 0.34 0.00 0.17 230 2.S 300 1. s 8.8 8.8 1.1 1. 4 9.1 l.S 1. 8 2.0 2.2 4 0.16 0.00 0.16 0.00 0.08 1 o.s 1 1. 0 o.o s.o 0.7 0.8 11. 0 0.9 1. 0 1. 1 1. 3 SA 1. OS 0.00 1. OS 0.00 O.S3 70 0.7 400 2.0 6.4 6.4 4.0 4.8 10.2 S.3 6.1 6.9 7.7 SB 0.70 0.00 0.70 0.00 0.3S 70 0.7 400 2.0 6.4 6.4 2.6 3.2 10.2 3.6 4.1 4.6 S.l 6A 1. 67 0.00 1. 67 0.00 0.84 4SO 8.0 1 1. 0 8.0 8.0 S.8 7.0 9.4 7.9 9.0 10.2 11. 4 6B 1. S6 0.00 1. S6 0.00 0.78 4SO 8.0 1 1. 0 8.0 8.0 S.4 6.6 9.4 7.4 8.4 9.S 10.6 7A 0.82 0.00 0.82 0.00 0.41 120 1. s 700 12.0 7.0 7.0 3.0 3.6 9.9 4.0 4.6 S.2 S.8 7B 1.70 0.00 1. 70 0.00 0.8S 120 1. s 700 12.0 7.0 7.0 6.2 7.S 9.9 8.4 9.6 10.8 12.1 8 0.6S 0.00 0.6S 0.00 0.33 80 1. 0 400 6.0 4.4 s.o 2.7 3.2 11. 0 3.6 4.1 4.6 S.l 9 o.so 0.00 o.so 0.00 0.2S 60 o.s 200 3.0 2.9 s.o 2.1 2.S 11. 0 2.7 3.1 3.S 3.9 10 2.08 0.00 2.08 0.00 1. 04 170 1. 7 600 13.0 7.4 7.4 7.4 9.0 9.7 10.1 11. s 13.0 14.S 11 0.4A 0.00 0.44 0.00 0.22 100 o.s 200 2.0 s.o s.o 1. 8 2.2 11. 0 2.4 2.7 3.1 3.S 14A 0.60 0.00 0.60 0.00 0.30 60 o.s 300 1. s S.l S.1 2.4 2.9 10.9 3.3 3.7 4.2 4.7 14B 2.2S 0.00 2.2S 0.00 1.13 2SO 2.0 430 3.0 10.9 10.9 6.8 8.3 8.3 9.4 10.7 12.1 13. 6 lS 2.88 0.00 2.88 0.00 1. 44 100 2.0 600 10.0 S.6 S.6 11. 4 13.7 10.6 lS.3 17.4 19.7 22.0 16 1. 98 0.00 1. 98 0.00 0.99 100 1. 0 sso 8.0 6.2 6.2 7.6 9.1 10.3 10.2 11. 6 13.1 14.7 17 1. 89 0.00 1. 89 0.00 0.9S 200 2.0 2SO s.o 6.2 6.2 7.2 8.7 10.3 9.7 11.1 12.S 14.0 18A 2.27 0.00 2.27 0.00 1.14 200 4.0 4SO s.o 6.9 6.9 8.3 10.1 9.9 11. 3 12.8 14.S 16.2 18B 1. 21 0.00 1. 21 0.00 0.61 200 4.0 260 4.0 S.1 S.l 4.9 S.9 10.9 6.6 7.S 8.S 9.S 19 1. 66 o.oo 1. 66 o.oo 0.83 100 1. 0 400 7.0 4.9 s.o 6.8 8.2 11. 0 9.1 10.4 11. 7 13.1 20 1. 91 0.00 1. 91 0.00 0.96 1 1. 0 1 1. 0 0,0 s.o 7.9 9. 4 11. 0 10.S 11. 9 13.S lS.l 21 2.49 0.00 2.49 0.00 1. 2S 1 1. 0 1 1. 0 o.o s.o 10.2 12.3 ll. 0 13.7 lS.6 17.6 19.6 22 O.S9 0.00 O.S9 o.oo 0.29 1 1. 0 1 1. 0 o.o s.o 2.4 2.9 11. 0 3.2 3.7 4.1 4.6 23 0.20 0.00 0.20 0.00 0.10 1 1.0 1 1. 0 0.0 s.o 0.8 1.0 ll. 0 1. 1 1. 2 1. 4 1. s 24 O.S3 0.00 O.S3 0.00 0.27 1 1. 0 1 1. 0 o.o s.o 2.2 2.6 11. 0 2.9 3.3 3.7 4.2 2S 0.16 0.00 0.16 0.00 0.08 1 1. 0 1 1. 0 O.Q s.o 0.7 0.8 11. 0 0.9 1. 0 1.1 1. 3 26· 0.20 0.00 0.20 0.00 0.10 1 1. 0 1 1. 0 0.0 s.o 0.8 1. 0 11. 0 1.1 1. 3 1. 4 1. 6 *E indicates Existing Drainage Condition All calculations performed using Microsoft Excel EXHIBIT C-1 EXHIBIT C-1 Rational Formula Drainage Area Calculations Revised April, 1996 < LU c :c ~ ~ a:: LU ..J < < c.. < ·< I-0 0 w w 0 ~ w c (!) 0 ..J ..J ..J (!) a:: ..J a:: zZ z ..J u.. u.. < w z ~~ ~~ a:: :c a:: < w < 0 z ..J > 9-:t ~ ..J w I-w I-(J ~ < W<t ~ a:: ~ a:: ~ ~ (!) ~ ..J d I-0 I-Cw (,/) w 0 Wo Wo ::> z ::> ..J cu w 0 LC) 0 0 a:: 0 z a:: w a:: CZ: 0 > ..J > ..J (!) ~ (!) ~ (,/) N LC) 0 ..... N LC) ..... c I-::> < a:: < 1-. 0 u.. 0 u.. u ::> 0 0 :!: 0 0 0 0 NO. AC. U.4 U.5 0.87 CA ' ' ' mm mm cfs cfs In/Hr cfs cfs cfs cfs 27 0.06 0.00 0.06 0.00 0.03 1 1. 0 1 1. 0 0.0 5.0 0.2 0.3 11.0 0.3 0.3 0.4 0.4 28 1.13 1.13 0.00 0.00 0.45 1 1. 0 1 1. 0 0.0 5.0 3.7 4 .5 11. 0 5.0 5.7 6.4 7.1 22-E 2.10 2.10 0.00 0.00 0.84 520 10.0 1 1. 0 s. e '8. 8 5.6 6.8 9.1 7.6 8.7 9.8 11. 0 23-E 0.45 0.45 o.oo 0.00 o. :rs 320 7.0 1 1. 0 5.1 5.1 1. 5 1. 8 10.9 2.0 2.2 2.5 2.8 24-E 0.84 0.84 0.00 0.00 0. 3-4 400 6.0 1 1. 0 7.7 7.7 2.4 2.9 9.6 3.2 3.7 4.1 4.6 25-E 0.16 0.16 0.00 0.00 0.06 1 1. 0 1 1. 0 0.0 5.0 0.5 0.6 11. 0 0.7 0.8 0.9 1. 0 26-E 0.04 0.04 0.00 0.00 0.02 1 1. 0 1 1. 0 0.0 5.0 0.1 0.2 11. 0 0.2 0.2 0.2 0.3 27-E 0.00 0.00 0.00 0.00 0.00 1 1. 0 1 1. 0 0.0 5.0 0.0 0.0 11.0 0.0 0.0 0.0 0.0 29 0.50 0.00 0.50 o.oo 0.25 75 1. 0 1 1. 0 1. 5 5.0 2.1 2.5 11. 0 2.7 3.1 3.5 3.9 30 0.67 0.00 0.67 0.00 0.34 75 1. 0 1 1. 0 1. 5 5.0 2.8 3.3 11. 0 3.7 4.2 4.7 5.3 31 0.16 0.00 0.16 0.00 0.08 50 1. 0 1 1. 0 0.8 5.0 0.7 0.8 11. 0 0.9 1. 0 1.1 1. 3 32 0.96 0.00 0.96 0.00 0.48 160 2.0 460 7.0 6.5 6.5 3.6 4.4 10.1 4.9 5.5 6.3 7.0 33 0.60 0.00 0.60 0.00 0.30 50 1. 0 1 1. 0 0.8 5.0 2.5 3.0 11. 0 3.3 3.8 4.2 4.7 34 2.15 0.00 2.15 0.00 1. 08 350 5.0 700 15.0 10.9 10.9 6.5 8.0 8.3 8.9 10.2 11. 6 13.0 35 0.50 0.00 0.50 0.00 0. 25 250 3.0 1 1. 0 5.4 5.4 2.0 2.4 10.7 2.7 3.1 3.5 3.9 29-E 1. 20 1. 20 0.00 0.00 0.48 480 7.0 1 1. 0 9.4 9.4 3.1 3.8 8.9 4.3 4.9 5.5 6.2 30-E 4.05 4.05 0.00 0.00 1. 62 650 7.0 1 1. 0 14.8 14.8 8.5 10.4 7.2 11.7 13.4 15.2 17.1 31-E 0.42 0.42 0.00 0.00 0.17 600 10.0 1 1. 0 11. 0 11. 0 1. 0 1. 2 8.3 1. 4 1. 6 1. 8 2.0 32-E 0.42 0.42 0.00 0.00 0.17 600 10.0 1 1. 0 11. 0 11. 0 1. 0 1. 2 8.3 1. 4 1. 6 1. 8 2.0 33-E 0.42 0.42 0.00 0.00 0.17 600 10.0 1 1. 0 11. 0 11. 0 1. 0 1. 2 8.3 1. 4 1. 6 1. 8 2.0 34-E 11. 00 11. 00 0.00 0.00 4.40 850 20.0 1 1. 0 13.1 13.1 24.5 30.0 7.7 33.8 38.6 43.7 49.2 35-E 2.75 2.75 0.00 0.00 1.10 620 18.0 1 1. 0 8.6 8.6 7.4 9.0 9.2 10.1 11. 5 13.0 14.6 36 0.57 0.57 0.00 0.00 0.23 1 1. 0 1 1. 0 o.o 5.0 1. 9 2.2 11. 0 2.5 2.9 3.2 3.6 Pt. B-E 15.15 15.15 0.00 0.00 6.06 326 2.1 800 11. 0 15.4 15.4 31. 0 38.1 7.1 43.0 49.3 55.8 62.9 *E indicates Existing Drainage Condition All calculations performed using Microsoft Excel EXHIBIT C-1 EXHIBIT C-2 INLET AND PIPE SIZE CALCULATIONS Revised April, 1996 -INLET SIZING PIPE SIZE COMPUTATIONS N= 0.014 :it: E 0 Cl) LI.. I-3 0. ...J ~ w :ii: ~ 0 _Q 0 0 I... ...J t1i ..., (/) "' z o.> :Q z (.) CJ') LI.. ~ "C c: I-0. O" > ...J ...J c c: 0 () w Cl) e :E z ~ Cl Cl :;:; UJ ro 0 0. er:: 0. 0 -., I-(/) (/) () c. ...J ~ z T" DESCRIPTION ~ er:: 0 0 () o.> o.> ·c ro 0 (.) ...J ...J LI.. I-I-I-0 0 LI.. CJ') (.) cfs cf s ft ft yr % " cf s lA 3.24 LOW POINT INLET 2 1. 62 s lA lB 0.30 s.oo 10 3.2 0.4S lS 4.0 lB S.77 LOW POINT INLET 2 2.88 s lB 4 0.82 S.16 10 8.9 1. 30 18 11.1 2 4.81 LOW POINT INLET 2 2.40 s 2 3B 0.47 6.32 100 6.9 0.78 18 8.7 3A 8.0S LOW POINT INLET 2 4.03 s 3A 3B 0.89 8.77 100 11. 7 0.97 21 14. 6 3B 1. SS LOW POINT INLET 2 0.77 s 3B 4 1. S3 8.77 100 20.1 0.48 27 20.1 4 0.88 RECESSED INLET ON GRADE 2 0.44 s 4 SB 2.43 9.01 100 31.6 0.69 30 31. 6 SA S.34 LOW POINT INLET 2 2.67 s SA SB O.S3 6.41 10 S.3 0.63 17 6.7 SB 3.S6 LOW POINT INLET 2 1. 78 s SB 7B 3.30 9.69 10 28.9 O.S7 30 28.8 6A 7.88 LOW POINT INLET 2 3.94 s 6A 6B 0.84 7.96 10 7.9 1. 38 17 9.8 68 7.36 LOW POINT INLET 2 3.68 s 68 7B 1. 62 7.96 10 lS.2 1. 67 21 19.0 7A 4.0S LOW POINT INLET 2 2.02 s 7A 7B 0.41 7.03 10 4.0 0.36 17 5.1 7B 8.39 LOW POINT INLET 2 4.19 s 7B HW 6.18 10.64 10 S2.0 1. 8S 30 Sl. 9 8 3.S7 RECESSED INLET ON GRADE 2 1. 78 s 8 9 0.33 S.00 10 3.6 o.ss lS 4.S 9 2.7S RECESSED INLET ON GRADE 2 1. 37 s 9 10 O.S8 S.32 10 6.2 0.63 18 7.7 10 10.06 RECESSED INLET ON GRADE 0.7 14.37 lS 10 11 1. 62 7.44 10 lS.6 1. 7 s 21 19.S 11 2.41 RECESSED INLET ON GRADE 0.7 3.4S s 11 HW 1. 84 7.S4 10 17.7 1. 10 24 22.1 14A 3.27 LOW POINT INLET 2 1. 64 s 14A 14B 0.30 S.12 10 3.3 0. 4 6 lS 4.1 148 9.36 LOW POINT INLET 2 4.68 s 14B lS 1. 43 10.93 10 11. 9 2.29 18 14.8 lS lS.31 LOW POINT INLET 2 7.66 10 lS 16 2.87 11. S8 10 23.2 1. 90 24 29.0 16 10.19 LOW POINT INLET 2 S.09 10 16 17 .3. 86 11. 72 10 31. 1 1. 16 27 31.1 17 9. 72 LOW POINT INLET 2 4.86 s 17 HW 4.80 12.44 10 37.7 0.59 33 37.7 18A 11. 26 LOW POINT INLET 2 S.63 10 18A 18 1. 14 6.93 10 11. 3 2.81 17 14.1 188 6.61 LOW POINT INLET 2 3.30 s 18B 19 0.61 S.10 10 6.6 0.31 21 8.3 19 9 .11 LOW POINT INLET 2 4.S6 s 19 HW 1. 44 S.46 10 lS.4 0.28 27 lS.3 34 8.94 Sloped Headwall 2 4.47 s 34 JB 1 1. 08 10.93 10 8.9 1. 30 18 11. 2 3S 2.69 Sloped Headwall 2 1. 34 s 3S JB 1 0.2S S.38 10 2.7 0.12 18 3.4 * Includes 2S% Flow increase for pipe sizes <27" dia. Exhibit C-2 ZONE X , . • 0 0 ZONE X Brazos County Unincorporated Areas 481195 EXHIBrr "E" TRAPEZOIDAL CHANNEL ANALYSIS NORMAL DEPTH COMPUTATION Ml;l.y 8, 1995 SHENANDOAH PHASE TWO OVERFLOW SECTION B-B 100 YEAR OVERFLOW AT WINDFREE CUL-DE-SAC (IDts 14 & 15, Block 17) ~==============:::r::===================================z======c======== PROGRAM INPUT DATA: DESCRIPTION Flow Rate (cubic feet per second) ••••••••••••••••••••.•• Channel Bottom Slope (feet per foot) •••••••••.•••.•••••• Manning's Roughness Coefficient (n-value) ••••••••••••••• Channel Side Slope -Left Side (horizontal/vertical) •••• Channel Side Slope -Right Side {horizontal/vertical) ••• Channel Bottom Width (feet) ••••••••••••••••••••••••••••• VALUE 18.1 0.0100 0.0300 4.00 4.00 10.0 ============~=========================================-=-======--=== PROGRAM RESULTS: DESCRIPTION VALUE --------------------------------------~----------------------------- Normal Depth (feet) ••••••••••••••••••••••••••••••••••••• Flow Velocity (feet per second) ••••••••••••••••••••••••• Froude Number (Flow is Sub-Critical) •••••••••••••••••••• Velocity Head (feet) •••••••••••••••••••••••••••••••••••• Energy Head (feet) ••••••••...••••••••••••••••••••••••••• Cross-Sectional Area of Flow (square feet) •••••••••••••• Top Width of Flow (feet) ••••.••••••••••••••••••••••••••• 0.52 2.87 0.759 0.13 0.65 6.30 14.17 ===========================================================z======== TRAPEZOIDAL CHANNEL ANALYSIS COMPUTER PROGRAM, Version 1.3 (c) 1986 Dodson & Associates, Inc., 7015 W. Tidwell, fl07, Houston, TX 77092 (713) 895-8322. A manual with equations & flow chart is available. 100 Year FloW = 57.88 CFS 10 Year FlCM = 39.8 CFS Overland FloW' = 18.1 CFS EXHIBIT ''F'' TRAPEZOIDAL CHANNEL ANALYSIS NORMAL DEPTH COMPUTATION May 8, 1995 SHENANDOAH PHASE TWO OVERFLOW SECTION B-B 100 YEAR OVERFLOW AT TIFFANY KNUCKLE (Lots 8 & 9, Block 17) ==========================================================c========= PROGRAM INPUT DATA: DESCRIPTION Flow Rate (cubic feet per second) ...........•....•..•... Channel Bottom Slope (feet per foot) ............•...•... Manning's Roughness Coefficient (n-value) .............. . Channel Side Slope -Left Side (horizontal/vertical) •... Channel Side Slope -Right Side (hori~ontal/vertical) •.. Channel Bottom Width (feet) •.••..••.•..........•....•... VALUE 12.4 0. 0160 0.0300 4.00 4.00 6.0 ==================================================================== PROGRAM RESULTS: DESCRIPTION Normal Depth (feet ) ••••••••••••••••••••••••••••••••••••• Flow Velocity (feet per second) ••••••••••••••••.•••••••• Froude Number (Flow is Sub-Critical) ••••••••.••••••••••• Velocity Hea.d (feet) .•.•.•.••••••••••••••...•....••••••• Energy Heaa ( feet ) ••••..•.•••••••••••••••••••••...•••••• Cross-Sectional Area of Flow (square feet) ••..•••.•••••• Top Width of Flow (feet) •.••••••..•••••••.•..•.••••••••• VALUE 0.48 3.29 0.935 0.17 0.64 3.77 9.82 ==================================================================== TRAPEZOIDAL CHANNEL ANALYSIS COMPUTER PROGRAM, Version 1.3 (c) 1986 Dodson & Associates, Inc., 7015 W. Tidwell, #107, Houston, TX 77092 (713) 895-8322. A·-.manual with equations & flow chart is available. 100 Year Flow = 40.19 CFS 10 Year Flow = 27.8 CFS OVerlarrl Flow = 12.4 CFS t . -·" TO:. FROM: DATE: RE: ·~~CITY OF COLLEGE STATION ~ ENGll'EERING DIVISION Post O ffice Box 9960 1101 Texas Avenue Co llege Station, Texas 77842-0960 (409) 764-35 70 MEMORANDUM David Moore , Building Official Kent Laza , City Engineer Ed Hard , Transportation Planner Vern W right, Engineering Technician Steve Horr:ieyer, Project Manager File(-cof') ~ Veronica Morgan, Assistant City Engineer ~-.__-J October 2, 1995 Driveway Loc ations i Attached is an approved drawing of driveway locations for Shenandoah II. As in Phase I, we are approving these driveway locations with the infrastructure plans so that the aprons may be constructed at the same time the curbing is poured . Please keep this in your file . . · o:/devserv/v :/sheniidr.doc DATE: TO: ATTN: 9 /2 2 /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 CX)LLEGE STATION ATTACHED PLEASE FIND: Proposed driveway layouts for Shenandoah Phase Two construction plus typical dirveway layout detail. THESE ARE TRANSMITTED TO YOU FOR THE FOLLOWING REASON: For Approval xx 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. 8' ------20· -----! 5• Thick Class A Cone. W/ /fJ 0 15• O.C.E.W. Provide Expansion Joint Material Leave (fJ Bars Exposed 12• ·.·· · :: .. : · : ....... , :-..·~ :·.:·: ... ·. . . 5 ' r~;t~~tl~~fv!~a -----.-... -r.-. -, --,.~. . ·.. :· ... 0 .· .. :. . . . . . . •. ·. . .. :.· · · · ·· · · .. · ¢ . : . ffa~~ , ~, ::~···· .· .. Q : ' f· Sid~w~I< ·.·•· Transition Curb Ht. _ .·· :. :·.".; : ...... "_:-.-:.·~t :< ... ·:: ...... ·· .. ·· .. ·::"-4' .. .·. ·. .. . . . . ·. . -· . . . ·-. .. ·, .. ·. t-------~30' ---------- TYPICAL DRIVEWAY LAYOUT DETAIL SCALE : 1• = 10' Note: In the absence of Sidewalk, The Drive- way wttl be graded 06 .63~ from the Gutter to the R.O. W .