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Home My WebLink About00072448DEVELOPMENT SERVICES TRANSMITTAL LETTER Name/Finn: jp e ►u-, +S; ��xGf�Vl Address: 00 6 yi t h a m Co O we T441 V4 . TX 7 ?94� Date: // — //— ZlaDZ Phone: 0 Fax: We are transmitting the following for Development Services to review and comment: (Check all that apply.): ❑ Master Development Plan w/ ❑ Redlines ❑ Development Permit App. ❑ Preliminary Plat w/ ❑ Redlines ❑ Conditional Use Permit Final Plat w/ ❑ Redlines ❑ Rezoning Application • FEMA CLOMA/CLOMR/LOMA/LOMR w/ ❑ Redlines ❑ Variance Request • Site Plan w/ ❑ Redlines ❑ Other - Please specify ❑ ❑ Grading Plan w/ ❑ Redlines ❑ Landscape Plan w/ ❑ Redlines ❑ Irrigation Plan w/ ❑ Redlines ❑ Building Construction Documents w/ ❑ Redlines INFRASTRUCTURE AND ENGINEERING DOCUMENTS All infrastructure documents must be submitted as a complete set. The following are included in the complete set: LJ Waterline Construction Documents w/ ❑ Redlines t Sewerline Construction Documents w/❑ Redlines LJ Drainage Construction Documents w/ ❑ Redlines Ef Street Construction Documents w/ ❑ Redlines ❑ Easement application with metes & bounds decsription Ef Drainage Letter or Report w/ ❑ Redlines ❑ Fire Flow Analysis w/ ❑ Redlines a TXDOT Driveway Permit ❑ TxDOT Utility Permit ❑ Other - Please specify Special Instructions: �4 wd be �J)iy e a� o (akr_ - TRANSMITTAL LETTER 1 of I TRANSMIT.DOC 10/14/2002 TPACON General Contractors Div. of CDS Enterprises, Inc. 1707 Graham Rd. • College Station, TX 77845 • 979 - 690 -7711 • Fax: 979 - 690 -9797 December 12, 2002 Bridgette George Asst. Development Coordinator City of College Station 1101 Texas Avenue South College Station, TX 77842 RE: Revised Construction Documents, Drainage Report & Estimate Oxburgh Drive — Phase 1 College Station, Texas Dear Ms. George: Attached are two (2) copies each of the revised construction documents, revised drainage report and the engineer's cost estimate for the above - mentioned project. Also attached are two (2) copies of the revised Sheet 4 to be included with the TxDOT driveway permit previously submitted. If you have any questions or need additional information, please do not hesitate to give me a call at (979) 690 -7711. Sincerely Yours, Joe Schultz, P.E. Engineering Manager 3 p Attachments TEXCON GENERAL CONTRACTORS 12- Dec -02 CONSTRUCTION COST ESTIMATE OXBURGH DRIVE, PHASE 1 COLLEGE STATION, TEXAS Item Storm Drainage Estimated Unit Estimated No. Description Quantity LF Price Cost 17 Sitework 181 LF $45.00 $8,145 1 Mobilization /Layout 1.0 LS $10,000.00 $10,000 2 Site Preparation 2.0 AC $3,000.00 $6,000 3 Topsoil Stripping & Replacement 1,220 CY $4.50 $5,490 4 Excavation 3,660 CY $3.50 $12,810 5 Lime Stabilized Subgrade 6,750 SY $3.00 $20,250 6 Concrete Curb & Gutter (Standard) 2,080 LF $8.00 $16,640 7 Base Material - 6" depth 5,770 SY $6.00 $34,620 8 Asphalt Paving - 1 1/2" depth 5,770 SY $5.00 $28,850 9 Concrete Apron 0 SF $5.50 $0 10 ADA Ramp - regular 0 EA $350.00 $0 11 ADA Ramp - corner 0 EA $450.00 $0 12 Concrete Sidewalk - 4' wide 8,310 SF $2.60 $21,606 13 Seeding & Hydromulch 5,000 SY $0.50 $2,500 14 Silt Fence 1,177 LF $2.50 $2,943 15 Construction Exit 30 TON $40.00 $1 Subtotal $162,909 Subtotal $184,285 Storm Drainage 16 Drainage Pipe - 18" RCP - structural 58 LF $38.00 $2,204 17 Drainage Pipe - 24" RCP - structural 181 LF $45.00 $8,145 18 Drainage Pipe - 27" RCP - structural 452 LF $48.00 $21,696 19 Inlets 5' wide / Junction boxes 2 EA $2,400.00 $4,800 20 Inlets 10' wide 1 EA $3,200.00 $3,200 21 Inlets 15' wide 1 EA $3,600.00 $3,600 22 8'x4' Box Culvert 240 LF $410.00 $98,400 23 Headwalls /wingwalls - triple 8'x4' box culvert 2 EA $18,000.00 $36,000 24 24" Sloped End Sections 2 EA $1,200.00 $2,400 25 Handrails 64 LF $60.00 $3,840 Subtotal $184,285 Page 1 of 2 Water Lines 26 8" Water PVC CL200 (C900) structural 150 LF $30.00 $4,500 27 12" Water PVC CL200 (C900) structural 945 LF $42.00 $39,690 28 12" Water PVC CL200 (C900) non - structural 85 LF $28.00 $2,380 29 24 "x12" Tapping Sleeve & Valve 1 EA $6,000.00 $6,000 30 Gate Valves - 8" 2 EA $600.00 $1,200 31 Gate Valves - 12" 2 EA $1,500.00 $3,000 32 M.J. Tees - 12 "x8" 2 EA $500.00 $1,000 33 M.J. Tees - 12" x 6" 1 EA $500.00 $500 34 M.J. Bend - 12" 11.25 deg. 6 EA $500.00 $3,000 35 2" Blow off Assembly 3 EA $450.00 $1,350 36 Air release valve 1 EA $2,800.00 $2,800 37 Fire Hydrant Assembly 1 EA $2,200.00 $2,200 38 20" Steel Casing w/ Spacers and Seals 40 LF $100.00 $4 Subtotal $71,620 Page 1 of 2 TEXCON GENERAL CONTRACTORS 12- Dec -02 CONSTRUCTION COST ESTIMATE OXBURGH DRIVE, PHASE 1 COLLEGE STATION, TEXAS Sanitary Sewer Lines Subtotal $0 Total Sitework $162,909 Total Storm Drainage $184,285 Total Water $71,620 Total Sanitary Sewer $0 TOTAL CONSTRUCTION $418,814 Engineering and Survey @ 6% $25,129 Contingency @ 5% $20,941 TOTAL $464,883 � PEE OF TE'A%�� . JOSEPH P • NAL -m Page 2 of 2 Drainage Report for Oxburgh Drive Phase 1 College Station, Texas November 2002 Revised December 2002 (Revisions in bold italics) Developer: Spring Creek CS Development, Ltd. 4490 Castlegate Drive College Station, Texas 77845 (979) 690 -7250 Prepared BV: TEXCON General Contractors 1707 Graham Road College Station, Texas 77845 (979) 690 -7711 CERTIFICATION I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report for the drainage design for the Oxburgh Drive, Phase 1 (Revised), was prepared by me in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners hereof. L b4c:5� Gingca. Urso, P.E. °a o T JOSE'N, P G 'ili...l e ...65? 4U (Z -1 2 -DZ ff� ha i y . f TABLE OF CONTENTS DRAINAGE REPORT - Revised OXBURGH DRIVE — PHASE 1 CERTIFICATION.................................................................................................................................. ............................... I TABLEOF CONTENTS ......................................................................................................................... ..............................2 LISTOF TABLES .................................................................................................................................... ..............................3 INTRODUCTION................................................................................................................................... ............................... 4 GENERALLOCATION AND DESCRIPTION .................................................................................. ............................... 4 FLOODHAZARD INFORMATION ..................................................................................................... ..............................4 DEVELOPMENTDRAINAGE PATTERNS ........................................................................................ ..............................4 DRAINAGEDESIGN CRITERIA ........................................................................................................ ............................... 4 STORM WATER RUNOFF DETERMINATION ............................................................................... ............................... 5 DETENTION FACILITY DESIGN ...................................................................................................... ............................... 6 STORMSEWER DESIGN ..................................................................................................................... ............................... 6 CULVERTDESIGN ............................................................................................................................... ............................... 7 FEMAFLOODPLAIN IMPACTS ........................................................................................................ ............................... 8 CONCLUSIONS...................................................................................................................................... ............................... 8 APPENDIXA .......................................................................................................................................... ............................... 9 Storm Sewer Inlet Design Calculations APPENDIX ........................................................................................................................................... .............................11 Storm Sewer Pipe Design Calculations APPENDIX .......................................................................................................................................... .............................16 Culvert Design Calculations APPENDIX .......................................................................................................................................... .............................19 Drainage Area C2: Curve Number & Time of Concentration Calculations EXHIBIT ............................................................................................................................................ ............................... 23 Post - Development Drainage Area Map — Culvert Design EXHIBIT ............................................................................................................................................ ............................... 25 Post - Development Drainage Area Map — Storm Sewer Design 2 LIST OF TABLES TABLE 1 — Rainfall Intensity Calculations ............................................................... ............................... 5 TABLE 2 — Post - Development Runoff Information — Storm Sewer Pipe Design Data .......................... 6 TABLE3 — Culvert No. 1 Design Data ..................................................................... ............................... 8 TABLE4 — Culvert No. 2 Design Data ..................................................................... ............................... 8 9 DRAINAGE REPORT - Revised OXBURGH DRIVE — PHASE 1 INTRODUCTION The purpose of this report is to provide the hydrological effects of the construction of Oxburgh Drive — Phase 1, and to verify that the proposed storm drainage system meets the requirements set forth by the City of College Station Drainage Policy and Design Standards. GENERAL LOCATION AND DESCRIPTION The project is located on a portion of a 62.18 acre tract located north of Greens Prairie Road along the West Frontage Road of State Highway 6 in College Station, Texas. This report addresses Oxburgh Drive, Phase 1, which is made up of 2.041 acres of the 62.18 acre tract. The site is pastureland with approximately 30% of the area wooded. The existing ground elevations range from elevation 261 to elevation 270. The general location of the project site is shown on the vicinity map in Exhibit A. FLOOD HAZARD INFORMATION The project site is located in the Spring Creek branch of the Lick Creek Drainage Basin. The site is located within a special flood hazard area according to the Flood Insurance Rate Map prepared by the Federal Emergency Management Agency (FEMA) for Brazos County, Texas and incorporated areas dated February 9, 2000, panel numbers 48041CO205 -D and 48041 CO201 -D. LJA Engineering & Surveying, Inc. submitted a Request for Conditional Letter of Map Revision ( CLOMR) to FEMA to outline a proposed 100 -year floodplain area. This CLOMR No. 00- 06 -844R was approved by FEMA on 9/9/2000. Oxburgh Drive passes through this proposed floodplain. DEVELOPMENT DRAINAGE PATTERNS Prior to development, the runoff flows in a southerly direction until it enters a tributary of Spring Creek or into the proposed regional detention facility. DRAINAGE DESIGN CRITERIA The design parameters for the storm sewer are as follows: • The Rational Method is utilized to determine peak storm water runoff rates for the storm sewer design. HEC -1 is used for Culvert No. 2 design. Design Storm Frequency Storm Sewer system Culverts 10 and 100 -year storm events 25 and 100 -year storm events • Runoff Coefficients Pre - development Post - development (commercial) C = 0.30 C = 0.70 4 • Curve Numbers - CN Refer to Appendix D for Curve Number calculations based on the soil classification and land use. Rainfall Intensity values for Brazos County for a minimum time of concentration of 10 minutes can be found in Table 1. Where a longer time of concentration was necessary, it is noted in the respective table, and the intensities are calculated with the higher values where required. Time of Concentration, t, — Due to the small sizes of the drainage areas, the calculated times of concentration, t, are less than 10 minutes. Therefore, a minimum t of 10 minutes is used in most cases to determine the rainfall intensity values. Where a longer time of concentration was necessary, it is noted and used accordingly. The time of concentration calculations for Drainage Area C2 are located in Appendix D. STORM WATER RUNOFF DETERMINATION The peak runoff values were determined in accordance with the criteria presented in the previous section for the 5, 10, 25, 50, and 100 -year storm events. The runoff coefficients are based on the future development of this tract. The drainage areas for post - development are shown on Exhibits A and B. Exhibit A shows the post- development drainage areas for the design of Culverts No. 1 and No. 2. Due to the size of the watershed draining to Culvert No. 2, the HEC -1 program was used to calculate the runoff for this structure. The runoff for the design of Culvert No. 1 and the storm sewer system was determined using the Rational Equation. Exhibit B shows the post - development drainage areas for the storm sewer design. Post - development runoff conditions for the storm sewer design are summarized in Table 2. TABLE 1 — Rainfall Intensity Calculations Rainfall Intensity Values (in /hr) Storm Event t _ 10 min I S 7.693 1 10 8.635 1 25 9.861 1 50 11.148 1100 11.639 Brazos County: 5 year storm b = 76 d = 8.5 e = 0.785 I = b / (t I = Rainfall Intensity ( in /hr) t = U(V *60) t c = Time of concentration (min) L = Length (ft) V = Velocity (ft/sec) 10 year storm 25 year storm 50 year storm 100 year storm b = 80 b = 89 b = 98 b = 96 d =8.5 d =8.5 d =8.5 d =8.0 e = 0.763 e = 0.754 e = 0.745 e = 0.730 (Data taken from State Department of Highways and Public Transportation Hydraulic Manual page 2 -16) TABLE 2 - Post - Development Runoff Information - Storm Sewer Pipe Design Data Area # Area C tc (min) 5 year storm 10 year storm 25 year storm 50 year storm 100 year storm 1 5 (in /hr) Q5 (cfs) 1 10 (in /hr) Q10 (cfs) 1 25 (in /hr) Q25 (cfs) 1 50 (in /hr) 450 (cfs) 1 100 (in /hr) 4100 (cfs) (acres) 19 0.26 0.7 10 7.693 1.40 8.635 1.57 9.861 1 1.79 11.148 2.03 11.639 2.12 20A 3.28 0.7 10 7.693 17.66 8.635 19.82 9.861 22.64 11.148 25.59 11.639 26.72 23 0.63 0.7 10 7.693 3.39 8.635 3.81 9.861 4.35 11.148 4.92 11.639 5.13 24 0.27 0.7 10 7.693 1.45 8.635 1.63 9.861 1.86 11.148 2.11 11.639 2.20 25 0.24 0.7 10 7.693 1.29 8.635 1.45 9.861 1.66 11.148 1.87 11.639 1.96 26 2.10 0.7 10 7.693 11.31 8.635 12.69 9.861 14.50 11.148 16.39 11.639 17.11 27 0.94 0.7 10 7.693 5.06 8.635 5.68 9.861 6.49 11.148 7.34 11.639 7.66 28 0.15 0.7 10 7.693 0.81 8.635 0.91 9.861 1.04 11.148 1.17 11.639 1.22 29 1 2.40 0.55 1 10 7.693 1 10.15 1 8.635 11.40 9.861 1 13.02 11.1481 14.71 1 11.6391 15.36 The Rational Method: Q = CIA Q = Flow (cfs) A = Area (acres) C = Runoff Coeff. I = Rainfall Intensity (in /hr) Brazos County 5 year storm 10 year storm b = 76 b = 80 d = 8.5 d = 8.5 e = 0.785 e = 0.763 DETENTION FACILITY DESIGN t = u(V *60) L = Length (ft) V = Velocity (ft/sec) 25 year storm 50 year storm b =89 b =98 d = 8.5 d = 8.5 e = 0.754 e = 0.745 100 year storm b = 96 d = 8.0 e = 0.730 The detention for this site is a regional facility designed by LJA Engineering & Surveying, Inc. and was previously constructed adjacent to this project. The detention facility is located adjacent to Spring Creek prior to Spring Creek entering the State Highway 6 right -of -way. The location of this proposed detention facility is shown on Exhibit A. The runoff from this project flows into the existing drainage channel constructed with the detention facility or into the detention pond. The detention facility was designed to control the increased runoff from the development of the Castlegate Subdivision and the Crowley Tract. Refer to the Request for Conditional Letter of Map Revision (CLOMR) for details of the design of the detention facility. STORM SEWER DESIGN The storm sewer piping for this project has been selected to be Reinforced Concrete Pipe (RCP) meeting the requirements of ASTM C -76, Class III pipe. The curb inlets will be cast -in- place concrete. Appendix A presents a summary of the storm sewer inlet design parameters and calculations. The inlets were designed based on a 10 -year design storm. As per College Station guidelines, the capacities of inlets in sump were reduced by 10% to allow for clogging. Inlets for Oxburgh Drive were located to maintain a gutter flow depth of 7" or less. These design depths will prevent the spread of water from reaching the crown of the road for the 10- year storm event. The runoff intercepted by the proposed storm sewer inlets was calculated using the following equations. The depth of flow in the gutter was determined by using the Straight Crown Flow equation. The capacities for the inlets in sumps (Inlets 1 -4) were calculated using the Inlets in Sumps, Weir Flow equation with a maximum allowable depth of 7" (5" gutter flow plus 2" gutter depression). The maximum depth of flow in the street gutter is 4.2" for the 10 -year storm event at Inlet No. 4. These equations and the resulting data are summarized in Appendix A. Appendix B presents a summary of the storm sewer pipe design parameters and calculations. All pipes are 18" in diameter or larger. For pipes with 18" and 24" diameters, the cross - sectional area is reduced by 25 %, as per College Station requirements. A summary of how this was achieved is shown in Appendix B as well. The pipes for the storm sewer system were designed based on the 10 -year storm event, and will also pass the 100 -year storm event without any headwater. Based on the depth of flow in the street determined for the 100 -year storm event, this runoff will be contained within the street right -of -way until it enters the storm sewer system. As required by College Station, the velocity of flow in the storm sewer pipe system is not lower than 2.5 feet per second, and it does not exceed 15 feet per second. As the data shows, even during low flow conditions, the velocity in the pipes will exceed 2.5 feet per second and prevent sediment build -up in the pipes. Appendix B contains a summary of the Manning pipe calculations. A 24" RCP pipe stub is planned for under Oxburgh Drive for draining future development of the townhouse tract. Flow calculations for this pipe will be addressed in a future report. CULVERT DESIGN The culverts for this project have been selected to be either Reinforced Concrete Pipe for Culvert No. 1 or Reinforced Concrete Precast Box Sections meeting the requirements of ASTM C -789 for Culvert No. 2. The headwalls at either end of Culvert No. 2 will be cast -in -place concrete. The safety end treatments at either end of Culvert No. 1 will be pre -cast sections. Data used for designing Culvert Nos. 1 & 2 can be found in Tables 3 & 4, respectively. Three 8'x4' box sections were selected for Culvert No. 2 because this is the same size utilized for the Proposed Culvert No. 4 in the CLOMR prepared by LJA Engineering, Inc. The slope of the culvert has been revised from the 1% used in the CLOMR to 0.65 %, which is the slope of the 25' wide drainage channel in the detention facility construction drawings, also prepared by LJA Engineering, Inc. The culverts were designed to pass the runoff from the 25 -year storm event with the upstream headwater at least 1 foot below the street top of curb. Culvert No. 1 passes the 25 -year and the 100 -year storm runoff without any headwater greater than the pipe diameter. Culvert No. 2 has a headwater elevation of 265.8 for the 25 -year storm event and 266.3 for the 100 -year storm event, both of which are more than 1 foot below the top of road elevation of 268.7. The 25- year exit velocity for Culvert No. 1 is 7.2 fps, and the 25 -year exit velocity for Culvert No. 2 is 5.5 fps. The downstream headwall for Culvert No. 2 will have energy dissipaters. Refer to Appendix C for the Manning's Equation and culvert calculator data for the culvert design. 7 FEMA FLOODPLAIN IMPACTS The proposed street crossing of the 100 -year floodplain was anticipated and included in the CLOMR. Culvert No. 2 is the same size and number of box sections as proposed in the CLOMR. The impact to the floodplain was previously addressed in the CLOMR. TABLE 3 — Culvert No. 1 Design Data Area # A C tc 5 year storm 10 year storm 25 year storm 50 year storm 100 year storm I Q5 110 Q10 1 25 Q25 Iw Q50 1 100 Q+oo (acres) (min) (in /hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in /hr) (cfs) 29 2.40 1 0.55 10 7.693 1 10.2 8.635 1 11.4 9.861 13.0 11.148 14.7 11.639 15.4 The Rational Method: Q = CIA Q = Flow (cfs) A = Area (acres) C = Runoff Coeff. I = Rainfall Intensity (in /hr) Brazos County I = b / (t t = u(V-60) t = Time of concentration (min) L = Length (ft) V = Velocity ftsec) 5 year storm 10 year storm 25 year storm 50 year storm 100 year storm b =76 b =80 b =89 b =98 b =96 d =8.5 d =8.5 d =8.5 d =8.5 d =8.0 e = 0.785 e = 0.763 e = 0.754 e = 0.745 e = 0.730 1— 24" Reinforced Concrete Pipe (RCP) with Safety End Treatments Length = 96', Slope = 0.9 FL in = 266.66 FL out = 265.80 Top of Road = 269.50 TABLE 4 — Culvert No. 2 Design Data Drainage Area Lag Time SCS Curve Number, CN No. (acres) (sq. mi.) (hrs) C -2 122.90 0.1920 0.22 80.9 HEC -1 Peak Runoff values: Q25 = 524 cfs Q100 = 682 cfs 3 — 8' (span) x 4' (rise) box culverts with headwalls & wingwalls Length = 78.7' FLin= 261.51 FL out = 261.00 Top of Road = 268.7' CONCLUSIONS The construction of this project will significantly increase the storm water runoff from this site. The proposed storm sewer system and culverts should adequately control the runoff and release it into the existing drainage channel. Also, the regional detention facility should adequately reduce the peak post - development runoff to less than the pre - development runoff for the design storm event. This will prevent any impact on the properties downstream of this project. APPENDIX A Storm Sewer Inlet Design Calculations N C w+ V d � U C � d 0 a V J o0 M � � O C v N V r N m M T C C II O O 11 O O O O � N G O ,C 04 O u � I I M m ''. r - H U N V",m N N' C! E r 10 N m N N m N N N m N '�. N N M O 0 N V I � N O T MIN m N O N r M N C! V M m N N N M o N M r N r m _ v O M o m M 0 M 0 M N 6 m N '2 N J r (,Pr N n O M N O m O N N M N N N V E q M I o O fD m N m I O M � I o 0 O O 0 0 m O O o m O M W. O q 0 1 <O � C7 N ' V N M r I O G w Q>!7 mIM Nl m f0 N O!O m. > d C .E o y 0 V � p m N � m N M Mir (O N O O M O N m D) () M M M M O O O O O O o 0 _ N m I N N m N O O O N O O O M a E e � 'Q y m o m m N N N r m NN v NIA- W M O NN C LL Q C L m J in sc d C N M R V NI C`7 _O m II C N v O O L O O 'X � O O CO O O II N N O '� m � C L 3 O O U 0 � L o N � N C C a to N O �_ ap 11 O T O T U O N r � a _ O fn O Cn fa U � 3 C N 0 L L C7 C Cn T J o0 M � � O o u rn 5 � LL T C C II O O 11 Q o w o f U N � N G O ,C ET 0 u � � N > CY J - II II � 11 � J JC7 >,E NI C`7 _O m II C N v O O L O O 'X � O O CO O O II N N O '� m � C L 3 O O U 0 � L o N � N C C a to N O �_ ap 11 O T O T U O N r � a _ O fn O Cn fa U � 3 C N 0 L L C7 C Cn T APPENDIX B Storm Sewer Pipe Design Calculations 11 N N M O M E o 4 E H O d m N M W fII � H C LL V 6 a N £ \° (O 00 (6 O N o C CO 4 W L6 to �p Q Q 00 L 0 _m ui a N (B � O O O O LL Ill eD (n N M U a N � � N M ; d E o to i N 0 N °' fn _ 01 F U) _Q N O A E L LL o o LO cli LL7 h � L Y L W N m o f/! a O v I-- L6 o d LL y M rn N M � L 3 0 ~ y LL m co N co N fl C c h N O M N W (�G E_ d `. h N 00 Co O > N N N N C a W crj 4) W N N O () N ?� Q •� ! h a O N _ c N N � o M C Q D W (.) 0 0 ev o o °O ai t N ," ° I, ° � �' a a 0� U� N to cp a to •� N M � N_ C Oo N `Fr w O Q N > O m Q Lo . 0 oa a * z Pipe 14 - 10 Year Storm Manning Pipe Calculator Given Input Data: Shape ........................... Solving for ..................... Diameter ........................ Flowrate ........................ Slope ........................... Manning's n ..................... Computed Results: Depth ........................... Area ............................ Wetted Area ..................... Wetted Perimeter ................ Perimeter ....................... Velocity ........................ Hydraulic Radius ................ Percent Full .................... Full flow Flowrate .............. Full flow velocity .............. Circular Depth of Flow 27.0000 in 17.3600 cfs 0.0050 ft /ft 0.0140 19.1867 in 3.9761 ft2 3.0219 ft2 54.1514 in 84.8230 in 5.7448 fps 8.0358 in 71.0620 % 20.3351 cfs 5.1144 fps Pipe 14 - 100 Year Storm Manning Pipe Calculator Given Input Data: Shape ............ Solving for ...... Diameter ......... Flowrate ......... Slope ............ Manning's n ...... Computed Results: Depth ............ Area ............. Wetted Area ...... Wetted Perimeter . Perimeter ........ Velocity ......... Hydraulic Radius . Percent Full ..... Full flow Flowrate Full flow velocity Circular Depth of Flow 27.0000 in 21.1800 cfs 0.0050 ft /ft 0.0140 23.2999 in 3.9761 ft2 3.6481 ft2 64.3454 in 84.8230 in 5.8058 fps 8.1641 in 86.2958% 20.3351 cfs 5.1144 fps Oxburgh Drive, Phase 1 College Station, Texas Pipe 15 - 10 Year Storm Manning Pipe Calculator Given Input Data: Shape ............ Solving for ...... Diameter ......... Flowrate ......... Slope ............ Manning's n ...... Computed Results: Depth ............ Area ............. Wetted Area ...... Wetted Perimeter . Perimeter ........ Velocity ......... Hydraulic Radius . Percent Full ..... Full flow Flowrate Full flow velocity Circular Depth of Flow 18.0000 in 3.8100 cfs 0.0050 ft /ft 0.0140 9.5519 in 1.7671 ft2 0.9525 ft2 29.3787 in 56.5487 in 4.0000 fps 4.6687 in 53.0659 % 6.8971 cfs 3.9030 fps Pipe 15 - 100 Year Storm Manning Pipe Calculator Given Input Data: Shape ........................... Circular Solving for ..................... Depth of Flow Diameter ........................ 18.0000 in Flowrate ........................ 5.1400 cfs Slope ........................... 0.0050 ft /ft Manning's n ..................... 0.0140 Computed Results: Depth ........................... 11.5793 in Area ............................ 1.7671 ft2 Wetted Area ..................... 1.2015 ft2 Wetted Perimeter ................ 33.5064 in Perimeter ....................... 56.5487 in Velocity ........................ 4.2779 fps Hydraulic Radius ................ 5.1638 in Percent Full .................... 64.3296 % Full flow Flowrate .............. 6.8971 cfs Full flow velocity .............. 3.9030 fps Oxburgh Drive, Phase 1 College Station, Texas APPENDIX C Culvert Design Calculations [L Culvert No. 1 - 25 Year Storm Manning Pipe Calculator Given Input Data: Shape ..... Solving for Diameter . Flowrate . Slope ..... Manning's n Circular Depth of Flow 24.0000 in 13.0000 cfs 0.0090 ft /ft 0.0130 Computed Results: Depth ............ Area ............. Wetted Area ...... Wetted Perimeter . Perimeter ........ Velocity ......... Hydraulic Radius . Percent Full ..... Full flow Flowrate Full flow velocity 13.4785 in 3.1416 ft2 1.8166 ft2 40.6637 in 75.3982 in 7.1562 fps 6.4330 in 56.1606 % 21.4615 cfs 6.8314 fps Culvert No. 1 - 100 Year Storm Manning Pipe Calculator Given Input Data: Shape ........................... Circular Solving for ..................... Depth of Flow Diameter ........................ 24.0000 in Flowrate ........................ 15.4000 cfs Slope ........................... 0.0090 ft /ft Manning's n ..................... 0.0130 Computed Results: Depth ........................... 15.0442 in Area ............................ 3.1416 ft2 Wetted Area ..................... 2.0727 ft2 Wetted Perimeter ................ 43.8547 in Perimeter ....................... 75.3982 in Velocity ........................ 7.4301 fps Hydraulic Radius ................ 6.8057 in Percent Full .................... 62.6840 % Full flow Flowrate .............. 21.4615 cfs Full flow velocity .............. 6.8314 fps Oxburgh Drive, Phase 1 College Station, Texas Culvert No. 2 - 25 Year Storm Culvert Calculator Entered Data: Shape ........................... Number of Barrels ............... Solving for ..................... Chart Number .................... Scale Number .................... Chart Description ............... Scale Description ............... Overtopping ..................... Flowrate ........................ Manning's n ..................... Roadway Elevation ............... Inlet Elevation ................. Outlet Elevation ................ Height .......................... Width ........................... Length .......................... Entrance Loss ................... Tailwater ....................... Rectangular 3 Headwater 9 2 BOX CULVERT WITH FLARED WINGWALL AND INLET TOP EDGE BEVEL WINGWALL FLARED 18 TO 33.7 DEGREES; INLET TOP EDGE BEVEL = 0.083D Off 524.0000 cfs 0.0140 268.7000 ft 261.5100 ft 261.0000 ft 48.0000 in 96.0000 in 78.7000 ft 0.4000 4.0000 ft Computed Results: Headwater ....................... Slope ........................... Velocity ........................ 265.7893 ft Outlet Control 0.0065 ft /ft 5.4583 fps Culvert No. 2 - 100 Year Storm Culvert Calculator Entered Data: Shape ........................... Number of Barrels ............... Solving for ..................... Chart Number .................... Scale Number .................... Chart Description ............... Scale Description ............... Overtopping ..................... Flowrate ........................ Manning's n ..................... Roadway Elevation ............... Inlet Elevation ................. Outlet Elevation ................ Height .......................... Width ........................... Length .......................... Entrance Loss ................... Tailwater ....................... Rectangular 3 Headwater 9 2 BOX CULVERT WITH FLARED WINGWALL AND INLET TOP EDGE BEVEL WINGWALL FLARED 18 TO 33.7 DEGREES; INLET TOP EDGE BEVEL = 0.083D Off 682.0000 cfs 0.0140 268.7000 ft 261.5100 ft 261.0000 ft 48.0000 in 96.0000 in 78.7000 ft 0.4000 4.0000 ft Computed Results: Headwater ....................... Slope ........................... Velocity ........................ 266.3371 ft Outlet Control 0.0065 ft /ft 7.1042 fps Oxburgh Drive, Phase 1 College Station, Texas APPENDIX D Drainage Area C2: Curve Number & Time of Concentration Calculations 19 SCS CURVE NUMBER CALCULATIONS OXBURGH DRIVE - DRAINAGE AREA C -2 Area - Ac. 122.9 sq. mi. 0.1920 Land Use Weighted Area, Ac. CN II* CN Residential -1/8 acre 3.49 92 2.6 Residential -1/4 acre 50.43 87 35.7 Farmstead 2.13 86 1.5 Commercial 6.78 95 5.2 Open Space /Grass 1.77 80 1.2 Pasture 27.63 83 18.7 Woods 29.62 79 19.0 Roads 1.05 98 0.8 Water 0.00 100 0.0 Total - CN II * Type "D" Soils 122.90 84.7 Average Runoff Condition ** CN = 80.9 CN I = 69.4 ARC CN = CN I = 0.75(CN II -CN 1) ** Average Runoff Conditions per Texas Engineering Technical Note No. 210- 18 -TX5 -SCS- USDA -March 1983. N C O r _R 7 v R U e w <o C d V C 0 U 0 O d E H � C 0 z d it 7 U N U m � 'C � Q s � as � � c s X 00 a z w z U 3 0 c m a� 0 d N c0 CL (n N f0 O) r O L N N LO N R) U- _0 c m a� a y C (9 C O N m 3 a O C6 o � N T a O N _ 7 N d > E 3 U 0 N II E_> (D N > L m 3 F � 00 C� -O J c II m F d > ~ O a U) C a m N U? 3 O 11 _o u N d (0 -O - O C N N 7 Q E C7 O II U > N N E ~ L a� 3 m o O J LL .. 25 r C� N �.5 FIGURE 1 • N + '—a 1 rr ►-t I I� O � j i I � i S\ 1 9� 3 \ i -,•^^. — J.� ;\ i' i 1 f tii..J i �:, • � � I 4 i . c r� -+. —f � i i I j � � � I i ..�. 4 � 7 l I e E ; "� - --1 ` j l l i � � � E j I S r I '• r +� � C--)v w LL- • i = i..i EXHIBIT A Post - Development Drainage Area Map — Culvert Design 23 EXHIBIT B Post - Development Drainage Area Map — Storm Sewer Design W