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HomeMy WebLinkAboutDrainage ReportDrainage Report · for The Barracks II Subdivision Section 200 College Station, Texas March 2013 Owner/Developer: Heath Phillips Investments, LLC 3302 General Parkway College Station, TX 77845 Prepared By: Schultz Engineering , LLC TBPE Firm No. 12327 P.O. Box 11995 College Station, TX 77842 2730 Longmire Drive, Suite A College Station, Texas 77845 (979) 764-3900 ENGINEER Drainage Report -Executive Summary The Barracks II Subdivision, Section 200 College Station, Texas SCHULTZ ENGINEERING, LLC. P.O. Box 11995 College Station, Texas 77842 Phone: (979) 764-3900 Fax: (979) 764-3910 O\VNER/DEVELOPER Heath Phillips Investments, LLC 3302 General Parkway College Station, TX 77845 Phone: (979) 690-5000 GENERAL DESCRIPTION AND LOCATION This project consists of the development of Section 200 of the Barracks II Subdivision in College Station. Section 200 is a single-family residential development, which will include the construction of utility and roadway infrastructure. Location: Description: • Area: • Proposed Land Use: • #of Lots: • Existing Land Use: • Land Description: Primary Drainage Facility: Flood Hazard Information: FEMAFIRM: Floodplain: Section 200 is located southeast of Section 100 of the Barracks II Development. The Barracks II Subdivision is a 108-acre development located midway between Rock Prairie Road and Cain Road in south College Station. It is bounded on the west by Holleman Drive South and on the east by Old Wellborn Road. 5.928 Acres Single Family Residential 28 lots Vacant The terrain slopes generally towards the north. Tributary B.3 of Bee Creek #48041C0305E, Dated May 16, 2012 None of this phase of the development lies within the floodplain. HYDROLOGIC CHARACTERISTICS The existing site is cleared. The elevations range from 309 to 302, sloping generally in a northerly direction. The runoff will be directed to the roadways and the proposed storm sewer system will discharge into the existing storm sewer system constructed with Deacon Drive and then discharges into the existing detention facilities. Ultimately, this runoff flows into Tributary B.3 of Bee Creek. GENERALSTORMWATERPLAN The drainage plan for this development will involve the installation of storm sewer pipes and inlets, which will collect and convey the runoff into the existing storm sewer system and then to the existing detention pond. The runoff that is collected by the existing detention ponds will be discharged into tributary B.3 of Bee Creek. The detention pond analysis and design for this phase is covered under the drainage report titled, "The Barracks Detention Facility Design City of College Station, Texas, Dated July 2012" prepared by Kimley-Horn. - COORDINATION & STORMW ATER PERMITTING This project has a Notice of Intent filed with the Texas Commission for Environmental Quality. No other permits are anticipated for this project. DRAINAGE DESIGN General Information: Street Design: Tc Methodology: Tc Minimum: Design Storm Event: Pipe Materials: Manning's n Values: Runoff Coefficients: Design Constraints: Design Software: Stormwater runoff from Section 200 of the subdivision will be collected by a storm sewer system and will ultimately discharge into tributary B3 of Bee Creek. The location of the drainage areas for evaluation of the gutter depth check, inlet sizing, pipe evaluation and channel sizing are shown on Exhibit A & B. Refer to Exhibit B for the locations of the inlets and storm sewer pipes. Typical Streets: Standard Cross-Section (3% cross-slope, 27' B-B Residential Roadway) Lay down curb and gutter on residential streets Towers Parkway: Collector Street Cross-Section (3% cross-slope, 38' B-B) Standard Curb and gutter Concrete Pavement Standard recessed curb inlets (5' & 10' in length) TR55 10 Minutes 10 year design storm & 100 year analysis for residential and collector streets & storm sewer Class III RCP, Profile Gasket in accordance with ASTM C443, ASTM C76 and Corrugated HDPE Storm Sewer Pipe with smooth interior 0.013 for pipes 0.018 for Streets 0.55 for developed lots 0.40 for undeveloped land upstream of property Max. water depth in gutter: 4.5" or 0.375' for the 10 year design storm for residential and collector streets Min. pipe flow velocity: 2.5 fi:>s Max. pipe flow velocity: 15 fi:>s 100-yr storm runoff maintained within the ROW (3" above curb) 25% reduction of cross-sectional area of pipes less than 24" in diameter Min. 1' freeboard for the 10 year design storm depth of flow Excel Spreadsheets, Hydraflow Express Extension for AutoCAD Civil 3D 2013, & Autodesk Civil 3D Storm Sewer Analysis. The software was used to compute pipe capacities, flow rates and velocities, compute hydraulic grade line elevations, headwater elevations, gutter depth & inlet sizing. .. Design Results: Detention Analysis: Applicable Exhibits: CONCLUSION The requirement for a 25% reduction in cross sectional area of pipes less than 24" diameter is achieved by using internal pipe diameters that are less than the standard diameter. The 24" diameter pipe areas were reduced by 25% and a 20.6" diameter pipe was used in the analysis and the 18" diameter pipe areas were reduced by 25% and a 15.6" diameter pipe was used in the analysis. The data presented in the Appendices indicates the gutter depth, inlet sizing, pipe sizes and channel sizing is in accordance with the requirements of and the City of College Station. The stormwater runoff from the Barracks II Subdivision was previously studied and detention ponds were designed for the entire development including this phase. See the drainage report titled; "The Barracks Detention Facility Design City of College Station, Texas, Dated July 2012". Exhibit A -Drainage Area Map -Overall Layout Exhibit B -Drainage Area Map -Storm Sewer System Layout Appendix Al -Drainage Area Summary Appendix A2 -Tc Calculations Post Development Appendix Bl -Depth of Flow in Gutter Appendix B2-Storm Sewer Inlet Summary Appendix C-Storm Sewer Pipe Summary Appendix D -Technical Design Summary The storm sewer, culverts & channel drainage system for Section 200 of the Barracks II Subdivision will function within the requirements and restrictions of the BCS Design Guidelines. CERTIFICATION I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report for the drainage design for The Barracks II, Section 200, was prepared by me in accordance with the requirements of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for the proposed drainage improvements have been issued. SCHULTZ ENGINEERING; LLC . - EXIDBITA DRAINAGE AREA MAP OVERALL DESIGN EXHIBITB DRAINAGE AREA MAP STORM SEWER SYSTEM LAYOUT APPENDIX A DRAINAGE AREA SUMMARY APPENDIX A The Barracks II Section 200 Drainage Area Summary Area# Area, A (acres) 301 24.73 302 8.03 303 13.92 305 0.58 306 0.06 307 0.43 307a 0.11 307b 0.31 308 2.09 308a 0.43 308b 1.66 309 0.58 309a 0.38 309b 0.20 310 .0.75 311 0.80 312 0.37 312a 0.10 312b 0.22 313 3.92 313a 0.10 313b 3.82 The Rational Method: Q = CIA I = b I (tc+d)8 c tc (min) 0.400 45.0 0.400 29.0 0.400 38.0 0.550 10.0 0.550 10.0 0.550 10.0 0.550 10.0 0.550 10.0 0.550 19.0 0.550 10.0 0.550 19.0 0.550 10.0 0.550 10.0 0.550 10.0 0.550 10.0 0.550 10.0 0.550 10.0 0.550 10.0 0.550 10.0 0.400 40.0 0.550 10.0 0.400 40.0 10 year storm 100 year storm 110 010 1100 0100 (in/hr) (cfs) (in/hr) (cfs) 3.840 37.99 5.291 52.34 5.036 16.18 6.878 22.09 4.274 23.80 5.868 32.67 8.635 2.75 11.639 3.71 8.635 0.28 11.639 0.38 8.635 2.04 11.639 2.75 8.635 0.52 11.639 0.70 8.635 1.47 11.639 1.98 6.381 7.33 8.657 9.95 8.635 2.04 11.639 2.75 6.381 5.83 8.657 7.90 8.635 2.75 11.639 3.71 8.635 1.80 11.639 2.43 8.635 0.95 11.639 1.28 8.635 3.56 11.639 4.80 8.635 3.80 11.639 5.12 8.635 1.76 11.639 2.37 8.635 0.47 11.639 0.64 8.635 1.04 11.639 1.41 4.139 6.49 5.688 8.92 8.635 0.47 11.639 0.64 4.139 6.32 . 5.688 8.69 Q =Flow (cfs) tc =Time of concentration (min) tc = U(V*60) L = Length (ft A = Area (acres) V =Velocity (ft/sec) C = Runoff Coeff. I = Rainfall Intensity (in/hr) Brazos County: 2 vearstorm I 0 y_ear storm 2 5 y_ear storm 50 y_ear storm b= 65 b= 80 b= 89 b= 98 d= 8 d= 8.5 d= 8.5 d= 8.5 e= 0.806 e = 0.763 e= 0.754 e= 0.745 JOO y_ear storm b= 96 d= 8.0 e= 0.730 APPENDIXA2 Tc CALCULATIONS POST DEVELOPMENT - AppendixA2 POST DEVELOPMENT TIME OF CONCENTRATION COMPUTATIONS The Barracks II Section 200 T "'"' = time of concentration for sheet flow (hr) l = length (ft) n = Manning's roughness P2 = 2-yr rainfall intensity (in/hr) for Brazos Co. = 4.5 in/hr S = slope (fVft) Drainage Sheet Flow Area# n Length Slope T..,... ft % min. 301 ,,0,24 '•· :Yl 100. 1.i1 ,,. 14 302 D.24 100 ·1.7 13 303 .t.0.2' . 100 "•. 1.49 ' 14 308 " '"Q.24 ' . 82 ~ ;a 7 3088 ·.,..-·"; ---7 313 •• o.24 . 'S> 10(J. • Q.83 17 3138 lli D.24, •; . ..; •. ~100 .• ""' tUJ3. · 17 Concentrated Flow Length Slope Velocity ft % ft/sec 'kl 1421 •." :"% 1.25 ""' 0.8;•., .. 587 (l.91 A, 0.7 ,; 1183 ' . '1.1 O.B ' 586 >i 0.8 . ' !).8 °"""'" 1 ....... 0.a~. 851 , . ,I• 1.1 . 0.7 .' '" .$51' , I~."' l,1 :"i .~~ .0.7 TR-55 Method Ve""'= water velocity in ditch (ft/sec) S = slope of ditch (ft/ft) V .., •• , = water velocity in gutter (ft/sec) S = slope of gutter (fVft) Section 200 Gutter Flow -1 T unpavea Length Slope Velocity min ft % ft/sec 30 ,,,•>! ""'," .,. "''',,. 14 " 0.0 23 ., .. ,~· 0,0 12 i• "' I• ~· .. ;. 0.0 12 ... . ·~· 0.0 .. 22 '0,0 22 r· ''<. ,r .. ,·o.o ·.;' T P•Yed min 0 0 0 0 0 0 0 Length ft :. '" l': 300 147 88 98 . "' T = travel time through ditch or gutter (min) L = length of travel path (ft) V = velocity (fVsec) Gutter Flow -2 Slope Velocity T p•vect Total % ft/sec min min ; -~ '" 0 45 1 2.0 1 2 29 1.25 ' 2.3 · 1 38 ... 0.0 0 19 ... " 0.0 0 19 1.29 2.3 1 40 . '1.29 2.3 1 40 Tc Design min . -,.45 .... 29 ' 38 " 19 I 19 ' 40 jt· "'° "" APPENDIX Bl DEPTH OF FLOW IN GUTTER .. APPENDIXB1 The Barracks II Section 200 Depth of Flow in Gutter (Refer to Exhibit B for Gutter Locations) Gutter/Inlet A Location c Area# (acres) 82001 A 309A 0.380 0.55 82001 6 3096 0.200 0.55 82003 310 0.750 0.55 82005 A 312A 0.100 0.55 82005 6 3126 0.220 0.55 S2006A 313A 0.100 0.55 82006 6 3136 3.820 0.40 82008 311 0.800 0.55 82011 A 307A 0.110 0.55 82011 6 3076 0.310 0.55 82021 A 308A 0.430 0.55 82021 6 3086 1.660 0.55 82031 305 0.580 0.55 Standard Curt> -10-yr stonn max design depth -4.5" Transverse !Crown) slope (ft/ft) 27 street = 0.0300 38 street " 0.0300 Slope ic (ft/ft) (min) 0.0061 10.000 0.0061 10.000 0.0061 10.000 0.0061 10.000 0.0072 10.000 0.0061 10.000 0.0072 40.000 0.0061 10.000 0.0061 10.000 0.0060 10.000 0.0061 10.000 0.0061 19.000 0.0069 10.000 5t[!lght Crown Flow 15olytd to find actyal depth of flow In gytter. vl; Q • 0.58 • (zln) • 5112 • y111 '* y •(QI [0.58 • (zln) • 5112]}211 n = Roughness Coefficient = 0.018 S = Street/Gutter Slope (ft/ft) y = Depth of flow at inlet (ft) z = Reciprocal of crown slope: I,. (In/hr) 6.327 6.327 6.327 6.327 6.327 6.327 2.870 6.327 6.327 6.327 6.327 4.563 6.327 10-year stonn 010 Q10 +bypass Y11NK:tu~ v (els) (els) (fl) (In) (fps) 1.80 1.86 0.243 2.91 1.84 0.95 0.95 0.189 2.27 1.60 3.56 -0.310 3.72 2.23 0.47 -0.146 1.75 1.34 1.04 -0.190 2.28 1.74 0.47 -0.146 1.75 1.34 6.32 0.373 4.47 2.73 3.80 -0.317 3.81 2.26 0.52 -0.151 1.81 1.38 1.47 -0.223 2.68 1.77 2.04 2.13 0.255 3.07 1.88 5.83 5.83 0.373 4.47 2.52 2.75 -0.275 3.30 2.19 I The Barracks II Section 200 Depth of Flow in Gutter (Refer to Exhibit B for Gutter Locations) Gutter/Inlet A Location c Area# (acres) 82001 A 309A 0.380 0.55 82001 8 3098 0.200 0.55 82003 310 0.750 0.55 82005A 312A 0.100 0.55 82005 8 3128 0.220 0.55 82006A 313A 0.100 0.55 82006 8 3138 3.620 0.40 82006 311 0.600 0.55 82011 A 307A 0.110 0.55 82011 8 3078 0.310 0.55 52021 A 306A o.~30 0.55 82021 8 3088 1.660 0.55 82031 305 0.580 0.55 Transverse !Crown) slope lft/ftl 27 street = 0.0300 38 street = 0.0300 Slope le (ft/ft) (min) 0.0061 10.000 0.0061 10.000 0.0061 10.000 0.0061 10.000 0.0072 10.000 0.0061 10.000 0.0072 40.000 0.0061 10.000 0.0061 10.000 0.0060 10.000 0.0061 10.000 0.0061 19.000 0.0069 10.000 Straight Crown Flow !Solved to find actual depth of flow In gutter. yl: Q" 0.56 • (z/n) • S112 • y113 ~ y •(QI [0.56 • (z/n) • S11'])311 n = Roughness Coefficient = 0.018 S = StreeUGutter Slope (ft/ft) y = Depth of flow at inlet (ft) z = Reciprocal of crown slope: 27' street = 33 1100 0100 (In/hr) (cfs) 11.639 2.43 11.639 1.26 11.639 4.60 11.639 0.64 11.639 1.41 11.639 0.64 5.668 6.69 11.639 5.12 11.639 0.70 11.639 1.96 11.639 2.75 6.657 7.90 11.639 3.71 APPENDIXB1 100-year stonn 100-year stonn 0100 + bypass Y100 Allowable v Top of Gutter Gutter ROW Freeboard (cfs) (fl) (In) Depth (fps) Curb FL Runoff, Elev. Elev. fl. 2.73 0.280 3.37 6" 1.66 304.63 304.33 304.61 305.06 0.45 1.26 0.211 2.53 6" 1.72 304.83 304.33 304.54 305.06 0.52 -0.347 4.16 6" 2.40 307.00 306.50 306.85 307.23 0.38 -0.163 1.95 6" 1.45 308.96 306.46 306.64 309.21 0.57 -0.212 2.55 6" 1.66 306.96 306.46 306.69 309.21 0.52 0.163 1.95 6" 1.45 306.96 306.46 306.64 309.21 0.57 -0.420 5.04 6" 2.96 306.96 306.46 306.90 309.21 0.31 -0.355 4.26 6" 2.44 307.00 306.50 306.66 307.23 0.37 0.169 2.02 6" 1.46 305.16 304.66 304.63 305.39 0.56 -0.250 3.00 6" 1.91 305.16 304.66 304.91 305.39 0.46 3.14 0.295 3.55 6" 1.69 305.16 304.66 304.96 305.39 0.43 7.90 0.418 5.01 8" 2.72 305.16 304.86 305,06 305.39 0.31 -0.308 3,69 8" 2.36 305.42 304.92 305.23 305.65 0.42 APPENDIXB2 STORM SEWER INLET SUMMARY - - APPENDIXB2 The Barracks II Section 200 Storm Sewer Inlets in Sump -Design Analysis Inlet Length 010 010 010 0100 0100 No. ft. cf s ft. in . cfs ft. S2001 10 2.81 0.221 2.65 4.01 0.280 S2005 5 1.52 0.233 2.80 2.05 0.284 S2006 10 6.80 0.399 4.79 9.33 0.492 S2011 5 1.99 0.279 3.35 . 2.69 0.341 S2021 10 7.95 0.443 5.31 11.04 0.551 * ROW elevation is 8" above gutter line so 100-yr storm runoff is contained within ROW Assume 10% clogging for design 0100* in. 3.37 3.41 5.91 4.09 6.61 - APPENDIX 82 The Barracks II Section 200 Storm Sewer Inlets on Grade -Design Analysis Inlet Length Street 010 No. ft. Slo~e cfs S2003 10 0.61% 3.56 S2008 10 0.61% 3.80 S2031 10 0.69% 2.75 * Inlet S2031 Drains into existing Hayes Street Assume 10% clogging for design Se = Sx + (a/w)* Eo Eo= Ow/O = 1 - [ 1 -Wrr]2·67 L=Kc*Q0.47*S0·3*(1 /( n*Se ))0·6 L10,ft. Design 11 .05 11.39 10.16 W = Width of Depressed Gutter (ft) = 2 Sx=Cross fl ow of Road Surface 0.03 T=Total Spread of water in gutter (ft) 12.5 a=Gutter depression depth (ft)= 0.33 n=Manning's Roughness Coefficient= 0.018 Kc= 0.6 Qw=Flow in width, W E=Efficiency of inlet or percentage of interception S=Longitudinal Slope Li=Curb opening length Se = Sx + (a/w)* Eo Eo= Ow/O = 1 - [ 1 -W/T]2'67 0.091412 0.372194 Bypass cf s 0.05 0.09 0.00 0100 L 100, ft. Bypass cf s Design cfs 4.80 12.71 0.30 5.12 13.10 0.38 3.71 11.69 0.11 APPENDIX Cl STORM SEWER PIPE SUMMARY APPENDIX C1 The Barracks II Section 200 Storm Sewer Pipe Design Analysis (10 yr Storm) HG10 pepth Pipe Pipe Pipe Pipe Size Length Slope No. (Inches) (feet) (%) Nonnal Depth Surcharged Q10 V10 Depth HG10 V10 (cfs) (fps) (feet) Slope (fas) Downstream Top Pipe Structure Elev. FL Upstream Top Pipe HG10 Structure Elev. FL Elev. Below Gutter (feet) 2002 42 56.37 0.50 43.64 5.74 2.59 0.19% 4.54 $2001 304.83 298.89 $2002 306.13 299.17 302.00 3.63 2003 42 147.82 0.50 43.61 5.39 2.74 0.19% 4.54 $2002 306.13 299.27 52003 307.00 300.01 302.76 3.74 2004 42 452.66 0.50 43.73 6.14 2.43 0.19% 4.55 $2003 307.00 300.11 52004 309.00 302.37 304.58 3.92 2005 42 74.42 0.50 43.71 6.27 2.39 0.19% 4.55 $2004 309.00 302.47 52005 308.98 302.84 305.51 2.97 2006 36 48.79 0.50 43.76 6.77 2.58 0.43% 6.19 S2005 308.98 303.34 $2006 308.98 303.59 306.62 1.86 2007 36 49.61 0.50 37.75 5.35 2.97 0.32% 5.34 52006 308.98 303.69 $2007 309.12 303.94 307.11 1.51 2008 24 31.01 0.50 3.66 3.80 1.08 0.03% 1.17 $2003 307.00 301.61 $2008 307.00 301.76 302.77 3.73 2011 42 142.08 0.55 37.05 5.73 2.30 0.14% 3.85 52001 304.83 298.89 52011 305.16 299.67 301.98 2.68 2012 42 125.51 0.30 37.12 5.26 2.41 0.14% 3.86 $201 1 305.16 299.77 52012 305.53 300.14 302.60 2.43 2021 30 31.01 0.35 9.80 4.26 1.19 0.06% 2.00 52011 305.16 300.77 52021 305.16 300.88 302.21 2.45 2031 24 126.83 0.20 2.70 3.09 0.99 0.01o/o 0.86 $2012 305.53 301.64 $2031 305.42 301 .9 302.77 2.15 2101 30 63.90 0.35 0.09 0.30 1.52 0.00% 0.02 $2005 308.98 303.84 $2101 307.93 304.14 305.51 1.92 2111 30 75.01 0.50 16.05 4.98 1.62 0.15% 3.27 $2012 305.53 301.64 $2111 305.27 302.02 303.20 1.57 2211 36 75.51 0.50 23.60 5.22 2.14 0.12% 3.34 $2012 305.53 300.64 $2211 305.36 301.02 303.18 1.68 Notes 1. Friction losses and minor losses for 18' diameter pipe are computed as for a 15.6' diameter pipe which represents a 25% reduction in pipe flow area. 2. Friction losses and minor losses for 24' diameter pipe are computed as for a 20.8" diameter pipe which represents a 25% reduction in pipe flow area. 3. HG at downstream end of Existing 42' Pipes Is 298.00. I APPENDIXC1 The Barracks II Section 200 Storm Sewer Pipe Design Analysis (100 yr Storm) HG10 Depth Pipe Pipe Pipe Pipe Size Length Slope No. (Inches) (feet) (%) Normal Oepth Surcharged Q100 V100 Depth HG100 V100 (els) (fps) (feet) Slope (fps) Downstream Top Pipe Structure Elev. FL Upstream Top Pipe HG100 Structure Elev. FL Elev. Below Gutter (feet) 2002 42 56.37 0.50 54.83 6.19 3.19 0.30% 5.70 S2001 304.83 298.89 S2002 306.13 299.17 302.63 3.00 2003 42 147.82 0.50 54.81 5.77 3.43 0.30% 5.70 82002 306.13 299.27 82003 307.00 300.01 303.54 2.96 2004 42 452.66 0.50 54.74 6.15 3.11 0.29% 5.69 82003 307.00 300.11 82004 309.00 302.37 305.16 3.34 2005 42 74.42 0.50 54.91 6.39 3.00 0.30% 5.71 S2004 309.00 302.47 S2005 308.98 302.84 306.14 2.34 2006 36 48.79 0.50 55.07 7.90 2.90 0.68% 7.79 82005 308.98 303.34 82006 308.98 303.59 307.40 1.08 ..-:,,7:, . 2007 36 49.61 0.50 47.15 6.67 3.00 0.50% 6.67 82006 308.98 303.69 S2007 309.12 303.94 308.12 o.so':J" .. · 2008 24 31.01 0.50 4.61 4.01 1.71 0.04% 1.47 82003 307.00 301.61 82008 307.00 301.76 303.54 2.96."f•\ 2011 42 142.08 0.55 50.69 6.05 2.95 0.25% 5.27 82001 304.83 298.89 82011 305.16 299.67 302.67 1.99 2012 42 125.51 0.30 50.81 5.58 3.15 0.25% 5.28 82011 305.16 299.77 82012 305.53 300.14 303.54 1.49 2021 30 31.01 0.35 13.62 4.69 1.85 0.11% 2.78 82011 305.16 300.77 52021 305.16 300.88 302.67 1.99 2031 24 126.83 0.20 3.56 3.34 1.68 0.02% 1.13 82012 305.53 301.64 82031 305.42 301.9 303.54 1.38 2101 30 63.90 0.35 0.14 0.40 2.15 0.00% 0.03 82005 308.98 303.84 82101 307.93 304.14 306.14 1.29 2111 30 75.01 0.50 21.85 4.75 2.38 0.28% 4.45 82012 305.53 301.64 S2111 305.27 302.02 303.88 0.89 2211 36 75.51 0.50 32.30 5.43 2.95 0.23% 4.57 S2012 305.53 300.64 S2211 305.36 301.02 304.01 0.85 Notes 1. Friction losses and minor losses for 18* diameter pipe are computed as for a 15.6' diameter pipe which represents a 25% reduction in pipe flow area. 2. Friction losses and minor losses for 24• diameter pipe are computed as for a 20.8' diameter pipe which represents a 25% reduction in pipe flow area. 3. HG at downstream end of Existing 42* Pipes is 299.71 - APPENDIXD TECHNICAL DESIGN SUMMARY SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY The Cities of Bryan and College Station both require storm drainage design to follow these Unified Stormwater Design Guidelines. Paragraph C2 of Section Ill (Administration) requires submittal of a drainage report in support of the drainage plan (stormwater management plan) proposed in connection with land development projects, both site projects and subdivisions. That report may be submitted as a traditional prose report, complete with applicable maps, graphs, tables and drawings, or it may take the form of a "Technical Design Summary". The format and content for such a summary report shall be in substantial conformance with the description in this Appendix to those Guidelines. In either format the report must answer the questions (affirmative or negative) and provide, at minimum, the information prescribed in the "Technical Design Summary" in this Appendix. The Stormwater Management Technical Design Summary Report shall include several parts as listed below. The information called for in each part must be provided as applicable. In addition to the requirements for the Executive Summary, this Appendix includes several pages detailing the requirements for a Technical Design Summary Report as forms to be completed. These are provided so that they may be copied and completed or scanned and digitized. In addition, electronic versions of the report forms may be obtained from the City. Requirements for the means (medium) of submittal are the same as for a conventional report as detailed in Section 111 of these Guidelines. Note: Part 1 -Executive Summary must accompany any drainage report required to be provided in connection with any land development project, regardless of the format chosen for said report. Note: Parts 2 through 6 are to be provided via the forms provided in this Appendix. Brief statements should be included in the forms as requested, but additional information should be attached as necessary. Part 1 -Executive Summary Report Part 2 -Project Administration Part 3 -Project Characteristics Part 4 -Drainage Concept and Design Parameters Part 5 -Plans and Specifications Part 6 -Conclusions and Attestation STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT Part 1 -Executive Summary This is to be a brief prose report that must address each of the seven areas listed below. Ideally it will include one or more paragraphs about each item. 1. Name, address, and contact information of the engineer submitting the report, and of the land owner and developer (or applicant if not the owner or developer). The date of submittal should also be included. 2. Identification of the size and general nature of the proposed project, including any proposed project phases. This paragraph should also include reference to STORMWATER DESIGN GUIDELINES Effective February 2007 Page 1of26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY applications that are in process with either City: plat(s), site plans, zoning requests, or clearing/grading permits, as well as reference to any application numbers or codes assigned by the City to such request. 3. The location of the project should be described. This should identify the Named Regulatory Watershed(s) in which it is located, how the entire project area is situated therein, whether the property straddles a watershed or basin divide, the approximate acreage in each basin, and whether its position in the Watershed dictates use of detention design. The approximate proportion of the property in the city limits and within the ET J is to be identified, including whether the property straddles city jurisdictional lines. If any portion of the property is in floodplains as described in Flood Insurance Rate Maps published by FEMA that should be disclosed. 4. The hydrologic characteristics of the property are to be described in broad terms: existing land cover; how and where stormwater drains to and from neighboring properties; ponds or wetland areas that tend to detain or store stormwater; existing creeks, channels, and swales crossing or serving the property; all existing drainage easements (or ROW) on the property, or on neighboring properties if they service runoff to or from the property. 5. The general plan for managing stormwater in the entire project area must be outlined to include the approximate size, and extent of use, of any of the following features: storm drains coupled with streets; detention I retention facilities; buried conveyance conduit independent of streets; swales or channels; bridges or culverts; outfalls to prin cipal watercourses or their tributaries; and treatment(s) of existing watercourses. Also, any plans for reclaiming land within floodplain areas must be outlined. 6. Coordination and permitting of stormwater matters must be addressed. This is to include any specialized coordination that has occurred or is planned with other entities (local, state, or federal). This may include agencies such as Brazos County government, the Brazos River Authority, the Texas A&M University System, the Texas Department of Transportation, the Texas Commission for Environmental Quality, the US Army Corps of Engineers, the US Environmental Protection Agency, et al. Mention must be made of any permits, agreements, or understandings that pertain to the project. 7. Reference is to be made to the full drainage report (or the Technical Design Summary Report) which the executive summary represents. The principal elements of the main report (and its length), including any maps, drawings or construction documents, should be itemized. An example statement might be: "One __ -page drainage report dated one set of construction drawings ( sheets) dated ____ , and a ___ -page specifications document dated ____ comprise the drainage report for this project." STORMWATER DESIGN GUIDELINES Effective February 2007 Page2 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 2 -Project Administration I Start (Page 2 .1) Engineering and Design Professionals Information .. Engineering Firm Name and Address: Jurisdiction Schultz Engineering, LLC City: Bryan P. 0 . Box 11995 ./ College Station College Station, Tx 77842 Date of Submittal: March2013 Lead Engineer's Name and Contact lnfo.(phone, e-mail, fax): Other: Joseph P. Schultz, PE email:joeschultz84@verizon.net Phone: 764-3900 fax: 764-3910 Supporting Engineering I Consulting Finn(s): Other contacts: nla Developer I Owner I Applicant Information Developer I Applicant Name and Address: Phone and e-mail: Heath Phillips Investments, LLC 979-690-5000 3302 General Parkway College Station, TX 77845 Property Owner(s) if not Developer I Applicant (&address): Phone and e-mail: Project Identification • ~ - Development Name: The Barracks II Subdivision, Section 100 Is subject property a site project, a single-phase subdivision, or part of a multi-phase subdivision? Multi-Phase Subdivision If multi-phase, subject property is phase 5 of 13 Legal description of subject property (phase) or Project Area: (see Section II, Paragraph B-3a) Crawford Burnett League, A-7 If subject property (phase)_is second or later phase of a project, describe general status of all earlier phases. For most recent earlier phase Include submittal and review dates. Housing construction is complete and on-going in the previous phases (Sections 100-102 & 300) General Location of Project Area, or subject property (phase): Between Old Welborn Road and Holleman Dr. South, North of Rock Prairie Road West and South of Cain Rd. In City Limits? Bryan: acres. College Station: 5.928 acres. STORMWATER DESIGN GUIDELINES Effective February 2007 Extraterritorial Jurisdiction (acreage): Bryan: College Station: Acreage Outside ET J: Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 2 -Project Administration I Continued (page 2.2) Project Identification (continued) Roadways abutting or within Project Area or Abutting tracts, platted land, or built subject property: developments: Old Wellborn Rd. The Barracks Section 100, 101 & 300, and CSISD Holleman Drive South Tract Named Regulatory Watercourse(s) & Watershed(s): Tributary Basin(s): Bee Creek TribB.3 Plat Information For Projector Subject Property (or Phase) Preliminary Plat File #: 12 -OOSOOJ4l Final Plat File #: NIA Date: March 2013 Name: THE BARRACKS II (PP) Status and Vol/Pg: submitted with this project If two plats, second name: File#: Status: Date: Zoning Information For Project or Subject Property (or Phase) '"T ' ;';,, Zoning Type: PDD Existing or Proposed? Existing Case Code: Case Date Status: Zoning Type: Existing or Proposed? Case Code: Case Date Status: . ' Stormwater Management Planning For Project or Subject Property (or Phase) ~ , . Planning Conference(s) & Date(s): Participants: NIA Preliminary Report Required? NIA Submittal Date Review Date Review Comments Addressed? Yes --No --In Writing? When? Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any. STORMWATER DESIGN GUIDELINES Effective February 2007 Page4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 2 -Project Administration I Continued (page 2.3) Coordination For Project or Subject Property (or Phase) Note: For any Coordination of stormwater matters indicated below, attach documentation describing and substantiating any agreements, understandings, contracts, or approvals. Coordination Dept. Contact: Date: Subject: With Other Departments of Jurisdiction City (Bryan or College Station) Coordination With Summarize need(s) & actions taken (include contacts & dates): Non-jurisdiction City Needed? Yes __ No-1._ Coordination with Summarize need(s) & actions taken (include contacts & dates): Brazos County Needed? Yes --No _{_ Coordination with Summarize need(s) & actions taken (include contacts & dates): TxDOT Needed? Yes --No _{_ Coordination with Summarize need(s) & actions taken (include contacts & dates): T AMUS Needed? Yes No ./ -- Permits For Project or Subject Property (or Phase) - As to stormwater management, are permits required for the proposed work from any of the entities listed below? If so, summarize status of efforts toward that objective in spaces below. Entity Permitted or Approved? US Army Crops of Permitted Engineers No --Yes_.:{__ US Environmental Protection Agency No ./ Yes - Texas Commission on Approved Environmental Quality No Yes ./ -- Brazos River Authority No -1_ Yes - STORMWATER DESIGN GUIDELINES Effective February 2007 Status of Actions (include dates) Permit approved. NOI for entire Subdivision Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -Progerty Characteristics I Start (Page 3.1) Nature and Scope.of Proposed Work Existing: Land proposed for development currently used, including extent of impervious cover? Proposed development is residential subdivision. High density. Impervious cover= 65% Site __ Redevelopment of one platted lot, or two or more adjoining platted lots. Development __ Building on a single platted lot of undeveloped land. Project __ Building on two or more platted adjoining lots of undeveloped land. (select all __ Building on a single lot, or adjoining lots, where proposed plat will not form applicable) a new street (but may include ROW dedication to existing streets). __ Other (explain): Subdivision __ Construction of streets and utilities to serve one or more platted lots. Development __:!._ Construction of streets and utilities to serve one or more proposed lots on Project lands represented by pending plats. Site projects: building use(s), approximate floor space, impervious cover ratio. Describe Subdivisions: number of lots by general type of use, linear feet of streets and Nature and drainage easements or ROW. Size of 28 Jots. Approximately 1442' of Streets. ProQosed Project 1. 72 ac. -ROW Is any work planned on land that is not platted If yes, explain: or on land for which platting is not pending? ./ No Yes -- -- FEMA Floodplains ~ "'. ' ,, .. Is any part of subject property abutting a Named Regulatory Watercourse I No_{_ Yes_{_ (Section II, Paragraph B1) or a tributary thereof? Is any part of subject property in floodplain I No_{_ Yes Rate Map area of a FEMA-regulated watercourse? -- Encroachment(s) Encroachment purpose(s): __ Building site(s) __ Road crossing(s) into Floodplain areas planned? __ Utility crossing(s) __ Other (explain): No ./ -- Yes -- If floodplain areas not shown on Rate Maps, has work been done toward amending the FEMA- approved Flood Study to define allowable encroachments in proposed areas? Explain. STORMWATER DESIGN GUIDELINES Effective February 2007 Page6 of 26 APPENDIX. D: TECH. DESIGN SUMMARY · As Revised August 2012 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -Progerty Characteristics I Continued (Page 3.2) Hydrologic Attributes of Subject Property (or Phase) ' Has an earlier hydrologic analysis been done for larger area including subject property? Yes Reference the study (&date) here, and attach copy if not already in City files. ./ Kimley-Hom Study ljuly 2012) -Analyzed downstream flooding potential and detention pond --design. Is the stormwater management plan for the property in substantial conformance with the earlier study? Yes_ ./ _ No - - If not, explain how it differs. No If subject property is not part of multi-phase project, describe stormwater management plan for the property in Part 4. --If property is part of multi-phase project, provide overview of stormwater management plan for Project Area here. In Part 4 describe how plan for subject property will comply therewith. Do existing topographic features on subject property store or detain runoff? _L No --Yes Describe them (include approximate size, volume, outfall, model, etc). Any known drainage or flooding problems in areas near subject property? __ No _./_ Yes Identify: The area around Cain Road and Old Wellborn Road. Based on location of study property in a watershed, is Type 1 Detention (flood control) needed? (see Table B-1 in Appendix B) Already Provided in previous phase _!_ Detention is required. --Need must be evaluated. __ Detention not required. What decision has been reached? By whom? If the need for How was determination made? Type 1 Detention must be evaluated: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 7 of26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -Pro~ert)l Characteristics I Continued (Page 3.3) Hydrologic Attributes of Subject Property (or Phase) (continued) Does subject property straddle a Watershed or Basin divide? _{_No --Yes If yes, describe splits below. In Part 4 describe design concept for handlinQ this. Watershed or Basin Larger acreage Lesser acreage Above-Project Areas(Section 11, Paragraph 83-a) Does Project Area (project or phase) receive runoff from upland areas? __ No _L Yes Size(s) of area(s) in acres: 1) 24.73 2) 3.92 3) 8.03 4) 13.92 Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable concentrated section(s), small creek (non-regulatory), regulatory Watercourse or tributary); Each instance is overland sheet flow and shallow concentrated flow. Flow determination: Outline hydrologic methods and assumptions: Rational Equation. C-value of0.40 Does storm runoff drain from public easements or ROW onto or across subject property? _{_No __ Yes If yes, describe facilities in easement or ROW: Are changes in runoff characteristics subject to change in future? Explain Yes. As adjoining tracts de velop and install detention ponds, their outflows will be conveyed through this tract by the proposed storm sewer. Conveyance Pathways (Section II, Paragraph C2) Must runoff from study property drain across lower properties before reaching a Regulatory Watercourse or tributary? ,/ No Yes Describe length and characteristics of each conveyance pathway(s). Include ownership of property(ies). STORMWATER DESIGN GUIDELINES Effective February 2007 Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX -1u..·-..:.··· APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -Progert~ Characteristics I Continued (Page 3.4) Hydrologic Attributes of Subject Property (or Phase) (continued) Conveyance Pathways (continued) Do drainage If yes, for what part of length? % Created by? __ plat, or easements __ instrument. If instrument(s), describe their provisions. exist for any part of pathway(s)? _L No Yes -- Where runoff must cross lower properties, describe characteristics of abutting lower property(ies). (Existing watercourses? Easement or Consent aquired?) Existing watercourse crosses the downstream properties. See Kimley Horn Report Pathway Areas Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). Detention Ponds constructed with previous phases. Nearby Drainage Do any of these have hydrologic or hydraulic influence on proposed stormwater Facilities design? No _:f_ Yes If yes, explain: -- See Kimley Horn Report, Phase 100 Report by Phillips Engineering and Phase 101 & 300 Report by Goodwin-Lasiter, Inc. STORMWATER DESIGN GUIDELINES Effective February 2007 Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 ,,. SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce(!t and Design Parameters I Start (Page 4.1) Stormwater Management Concept Discharge(s) From Upland Area(s) If runoff is to be received from upland areas, what design drainage features will be used to accommodate it and insure it is not blocked by future development? Describe for each area, flow section, or discharge point. Runoff from upland areas wi/1 be captured in publicly owned storm drain systems as the subdivision develops. Discharge(s) To Lower Property(ies) (Section II, Paragraph E1) Does project include drainage features (existing or future) proposed to become public via platting? --No _ ./ _Yes Separate Instrument? _ ./ -No -_Yes Per Guidelines reference above, how will __ Establishing Easements (Scenario 1) runoff be discharged to neighboring _:/___ Pre-development Release (Scenario 2) property(ies)? Combination of the two Scenarios -- Scenario 1: If easements are proposed, describe where needed, and provide status of actions on each . (Attached Exhibit# ) Scenario 2: Provide general description of how release(s) will be managed to pre-development conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit# ) Detention Pond. Combination: If combination is proposed, explain how discharge will differ from pre- development conditions at the property line for each area (or point) of release. If Scenario 2, or Combination are to be used, has proposed design been coordinated with owner(s) of receiving property(ies)? documentation. STORMWATER DESIGN GUIDELINES Effective February 2007 ./ No Page 10 of 26 --Yes Explain and provide APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concept and Design Parameters I Continued (Page 4.2) Stormwater Management Concept (continued) Within Project Area Of Multi-Phase Project Will project result in shifting runoff between Basins or Identify gaining Basins or Watersheds and acres shifting: between f-W_h_a_t -de-s-ig_n_a-nd-m-iti-. g_a_ti_o_n-is-us_e_d_t_o_c_o_m_p_e_n_sa_t_e_f_o_r -in-c-re_a_s-ed-ru_n_o...,,.ff,-------1 Watersheds? from gaining basin or watershed? ./ No Yes How will runoff from Project Area be mitigated to pre- development conditions? Select any or all of 1, 2, and/or 3, and explain below. 1. __ With facility(ies) involving other development projects. 2. __:/__Establishing features to serve overall Project Area. 3. __:{__On phase (or site) project basis within Project Area. 1. Shared facility (type & location of facility; design drainage area served; relationship to size of Project Area): (Attached Exhibit# ) 2. For Overall Project Area (type & location of facilities): (Attached Exhibit# A ) Existing detention ponds will serve the proposed development. 3. By phase (or site) project: Describe planned mitigation measures for phases (or sites) in subsequent questions of this Part. C'-· "O Cl> (/) c: Cl> ~ >-a: (/) c: Cl 'iii Q) 0 Oz (ij J.tl ~ Are aquatic echosystems proposed? __ No project(s)? __ Yes In which phase(s) or Are other Best Management Practices for reducing stormwater pollutants proposed? __ No _L Yes Summarize type of BMP and extent of use: Silt fences, construction exits, rock check dams, seeding and erosion matting. If design of any runoff-handling facilities deviate from provisions of B-CS Technical Specifications, check type facility(ies) and explain in later questions. __ Detention elements __ Conduit elements __ Channel features __ Swales __ Ditches __ Inlets __ Valley gutters __ Outfalls __ Culvert features __ Bridges Other STORMWATER DESIGN GUIDELINES Effective February 2007 Page 11of26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concept and Design Parameters I Continued (Page 4.3) Stormwater Management Concept (continued) Within Project Area Of Multi-Phase Project (continued) Will Project Area include bridge(s) or culvert(s)? _L No __ Yes general size and In which phase(s). Identify type and If detention/retention serves (will serve) overall Project Area, describe how it relates to subject phase or site project (physical location, conveyance pathway(s), construction sequence): The detention ponds constructed with the previous phases will serve this phase. Runoff will enter the pond through the underground stonn drains. Within Or Serving Subject Property (Phase, or Site) If property part of larger Project Area, is design in substantial conformance with earlier analysis and report for larger area? _L Yes No, then summarize the difference(s): Identify whether each of the types of drainage features listed below are included, extent of use, and general characteristics. C'-· "'C Q) C/l C/l Q) ::J >-C/l Q) I ..c: .B '5 Typical shape? I Surfaces? Steepest side slopes: I Usual front slopes: 1 ·Usual back slopes: Flow line slopes: least. ____ _ Typical distance from travelway: typical greatest ___ _ (Attached Exhibit# ) Are longitudinal culvert ends in compliance with B-CS Standard Specifications? ___ Yes No, then explain: At intersections or otherwise, do valley gutters cross arterial or collector streets? ./ No __ Yes If yes explain: Are valley gutters proposed to cross any street away from an intersection? _:f_ No __ Yes Explain: (number of locations?) STORMWATER DESIGN GUIDELINES Effective February 2007 Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concept and Design Parameters I Continued (Page 4.4) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) C'· -0 Q) I/) I/) Q) ~ >-E i"I I/) c: -~ ~ Gutter line slopes: Least 0.60 Usual 0.60 Greatest 1.50 Are inlets recessed on arterial and collector streets? _!!._Yes identify where and why. __ No If "no", Will inlets capture 10-year design stormflow to prevent flooding of intersections (arterial with arterial or collector)? _L_ Yes __ No If no, explain where and why not. Will inlet size and placement prevent exceeding allowable water spread for 10-year design storm throughout site (or phase)? _ ,/ _Yes __ No If no, explain. Sag curves: Are inlets placed at low points? _L_ Yes __ No Are inlets and conduit sized to prevent 100-year stormflow from ponding at greater than 24 inches? _L_ Yes __ No Explain "no" answers. Will 100-yr stormflow be contained in combination of ROW and buried conduit on whole length of all streets? ~Yes __ No If no, describe where and why. Do designs for curb, gutter, and inlets comply with B-CS Technical Specifications? ,/ Yes __ No If not, describe difference(s) and attach justification. Are any 12-inch laterals used? _L_ No used. ___ Yes Identify length(s) and where Pipe runs between system I Typical 108' Longest 452 access points (feet): ---------- Are junction boxes used at each bend? ,/ Yes __ No If not, explain where and why. i I f----------------------------------~----------------___, iii Are downstream soffits at or below upstream soffits? Least amount that hydraulic .!!!. Yes _!!._ No __ If not, explain where and why: grade line is below gutter line (system-wide): STORMWATER DESIGN GUIDELINES Effective February 2007 Page 13 of 26 0.5' APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concept and Design Parameters I Continued (Page 4.5) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Ui' Q) (.) c: ro iii .!: Q) .... -o -g E ::::l .... . !: .E C:· 0 .E (.) c: -·-~ ~ ..... ro VJ VJ ~ Q) c: 32 ·-> ~ e "O a. E «> .8 ~ en VJ 2 ~ ro a. Q) VJ Describe watercourse(s), or system(s) receiving system discharge(s) below (include design discharge velocity, and angle between converging flow lines). 1) Watercourse (or system), velocity, and angle? Bee Creek Trib B.3 @ 0°, < 2 fps 2) Watercourse (or system), velocity, and angle? 3) Watercourse (or system), velocity, and angle? For each outfall above, what measures are taken to prevent erosion or scour of receiving and all facilities at juncture? 1) Outfall from this development will occur into downstream pipes from prev. phases 2) c: ..2. 3) C'-· VJ Q) ~ VJ Are swale(s) situated along property lines between properties? _£__No __ Yes Number of instances: For each instance answer the following questions. Surface treatments (including low-flow flumes if any): iii Q) Flow line slopes (minimum and maximum): fl -g 0 ~ z Outfall characteristics for each (velocity, convergent angle, & end treatment). iY'I VJ Q) ~ Will 100-year design storm runoff be contained within easement(s) or platted drainage ROW in all instances? __ Yes __ No If "no" explain: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters I Continued (Page 4.6) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) en Are roadside ditches used? _L_ No __ Yes If so, provide the following: Q) Is 25-year flow contained with 6 inches of freeboard throughout? __ Yes No .s::: --(.) Are top of banks separated from road shoulders 2 feet or more? __ Yes No ..... --iS Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No Q) -----0 For any "no" answers provide location(s) and explain: 'iii -0 C1l 0 0::: If conduit is beneath a swale, provide the following information (each instance). Instance 1 Describe general location, approximate length: en Q) Is 100-year design flow contained in conduit/swale combination? Yes No >-----lj If "no" explain: c: Space for 100-year storm flow? ROW Easement Width 0 C1l z iii Swale Surface type, minimum Conduit Type and size, minimum and maximum ,,~ and maximum slopes: slopes, design storm: 0 :.;:::; C'· '6 en -0 Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): cu C1l c: >-c: C1l c: .s::: C1l (.) ..... c: .E Q) c: Access Describe how maintenance access is provided (to swale, into conduit): a. 0 0:.;:::; ...... C1l 0 E :J ..... ~ .E .5 .5 Q) Instance 2 Describe general location, approximate length: -0 E Q) C1l en en :J en Q) Is 100-year design flow contained in conduit/swale combination? Yes No c: -0 0 "> ----:.;:::; 0 If "no" explain: C1l ..... c: a. :c Q) Space for 100-year storm flow? ROW E Q) Easement Width 0 .s::: 0 en Swale Surface type, minimum Conduit Type and size, minimum and maximum ..... Q) ·s -ro and maximum slopes: slopes, design storm: -0 ..... c: C1l 0 a. 0 Q) Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): Q> en ro c: ~ -2-en Q) Access Describe how maintenance access is provided (to swale, into conduit): ..... <{ STORMWATER DESIGN GUIDELINES Effective February 2007 Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concept and Design Parameters I Continued (Page 4.7) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) c: "(i'j c.. E x 0 UJ ~ If ''yes" provide the following information for each instance: Instance 1 Describe general location, approximate length, surfacing: :g Iii Is 100-year design flow contained in swale? __ Yes __ No Is swale wholly c: a> within drainage ROW? __ Yes __ No Explain "no" answers: .; ,.I f--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~---1 u Access Describe how maintenance access is provide: ~ 0 ;z ~ 'I 1--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~--< ~ Instance 2 Describe general location, approximate length, surfacing: Q) ·c <'· ::J (/) ..c c :5 Q) o E .L:: Q) -(/) '§ m (/) ~ Q) 0 ~~ (/) 0 ~~ C'-· "'C ]5 ::J c.. .£ Q) (/) m 0 -c.. c.. 0 x ..... UJ c.. (/) (/) -Q) c: >-Q) E I Q) > e c.. -~ 0 z Qi 'I c: c: m .L:: (.) Is 100-year design flow contained in swale? __ Yes __ No Is swale wholly within drainage ROW? __ Yes __ No Explain "no" answers: Access Describe how maintenance access is provided: Instance 3, 4, etc. If swales are used in more than two instances, attach sheet providing all above information for each instance. "New" channels: Will any area(s) of concentrated flow be channelized (deepened, widened, or straightened) or otherwise altered? __ No __ Yes If only slightly shaped, see "Swales" in this Part. If creating side banks, provide information below. Will design replicate natural channel? __ Yes __ No If "no'', for each instance describe section shape & area, flow line slope (min. & max.), surfaces, and 100-year design flow, and amount of freeboard: Instance 1: Instance 2: Instance 3: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters I Continued (Page 4.8) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Existing channels (small creeks}: Are these used? ~ No --Yes If ''yes" provide the infonnation below. Will small creeks and their floodplains remain undisturbed? __ Yes No How many disturbance instances? Identify each planned location: For each location, describe length and general type of proposed improvement (including floodplain changes): For each location, describe section shape & area, flow line slope (min. & max.), surfaces, and 100-year design flow. 'C Qi ::J c :e Watercourses (and tributaries}: Aside from fringe changes, are Regulatory 0 Watercourses proposed to be altered? ~No Yes Explain below. ~ -- I/) c Submit full report describing proposed changes to Regulatory Watercourses. Address Qi existing and proposed section size and shape, surfaces, alignment, flow line changes, E Qi length affected, and capacity, and provide full documentation of analysis procedures > 0 and data. Is full report submitted? Yes No If "no" explain: ..... --a. E Q) c c ell All Proposed Channel Work: For all proposed channel work, provide information ..c. t) requested in next three boxes. If design is to replicate natural channel, identify location and length here, and describe design in Special Design section of this Part of Report. Will 100-year flow be contained with one foot of freeboard? --Yes --No If not, identify location and explain: Are ROW I easements sized to contain channel and required maintenance space? --Yes --No If not, identify location(s) and explain: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage ConceQt and Design Parameters I Continued (Page 4.9) Stormwater Management Concept (continued) - Within Or Serving Subject Property (Phase, or Site) (continued) How many facilities for subject property project? For each provide info. below. For each dry-type facilitiy: Facility 1 Facility 2 Acres served & design volume + 10% 100-yr volume: free flow & plugged Design discharge (10 yr & 25 yr) Spillway crest at 100-yr WSE? __ yes --no __ yes --no Berms 6 inches above plugged WSE? __ yes --no __ yes --no Explain any "no" answers: en Cl.) >- I For each facility what is 25-yr design Q, and design of outlet structure? Facility 1: 0 z Facility 2: 11 Do outlets and spillways discharge into a public facility in easement or ROW? Facility 1: __ Yes No Facility 2: Yes No -- -- --C'-· If "no" explain: "C Cl.) en 0 c.. 0 .... a.. For each, what is velocity of 25-yr design discharge at outlet? & at spillway? en Cl.) Facility 1: & Facility 2: & ~ '(j Are energy dissipation measures used? No Yes Describe type and ro ----u_ location: c: .Q c Cl.) -Cl.) 0 Cl.) For each, is spillway surface treatment other than concrete? Yes or no, and describe: .... <{ Facility 1: Facility 2: For each, what measures are taken to prevent erosion or scour at receiving facility? Facility 1: Facility 2: If berms are used give heights, slopes and surface treatments of sides. Facility 1: Facility 2: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 18 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce[!t and Design Parameters I Continued (Page 4.10) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Do structures comply with B-CS Specifications? Yes or no, and explain if "no": I/) Facility 1; Q) :.;:; =u ~ Q) Facility 2: u. :::J c: c :+:: 0 c: :.;:; 0 c: u Q) ~ Qi For additional facilities provide all same information on a separate sheet. 0 Are parking areas to be used for detention? __ No --Yes What is maximum depth due to required design storm? Roadside Ditches: Will culverts serve access driveways at roadside ditches? --No --Yes If "yes", provide information in next two boxes. Will 25-yr. flow pass without flowing over driveway in all cases? --Yes --No Without causing flowing or standing water on public roadway? --Yes --No Designs & materials comply with B-CS Technical Specifications? __ Yes --No Explain any "no" answers: C'· I/) Cl c: "Vi Are culverts parallel to public roadway alignment? __ Yes No Explain: I/) 0 --.... I/) u Q) 2 >-ro I > ·;:: Creeks at Private Drives: Do private driveways, drives, or streets cross drainage a. iii ways that serve Above-Project areas or are in public easements/ ROW? 1:l 0 No Yes If "yes" provide information below. Q) z ----~~1 How many instances? Describe location and provide information below. Q) Location 1: > ::; u Q) Location 2: .... <( Location 3: For each location enter value for: 1 2 3 Design year passing without toping travelway? Water depth on travelway at 25-year flow? Water depth on travelway at 100-year flow? For more instances describe location and same information on separate sheet. STORMWATER DESIGN GUIDELINES Effective February 2007 Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters I Continued (Page 4.11) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Named Regulato!)l Watercourses {&Tributaries}: Are culverts proposed on these facilities? No __ Yes, then provide full report documenting assumptions, criteria, analysis, computer programs, and study findings that support proposed design(s). Is report provided? __ Yes --No If "no", explain: ~ Arterial or Major Collector Streets: W ill culverts serve these types of roadways? Q) No Yes How many instances? For each identify the .s::. Cf) ---- Q) location and provide the information below. -Cf) ro Instance 1: Q) ..... >-~ I~ Instance 2: Instance 3: c 0 :;:::; Yes or No for the 100-year design flow: 1 2 3 o ro z E ~1~ Headwater WSE 1 foot below lowest QUrb top? Spread of headwater within ROW or easement? E C'· ro Is velocity limited per conditions (Table C-11 )? Cf) Cf) g> -0 Explain any "no" answer(s): ·-c ~ ro 0 c ..... 0 U:.;:; >. ro ro u ~..Q -0 Q) ro ..c Minor Collector or Local Streets: Will culverts serve these types of streets? 0 ·-.......... (.) (.) No Yes How many instances? for each identify the ·-Cf) -----Q) -g -0 location and provide the information below: a. Q) -a. Instance 1: ro >. --0 >. Instance 2: Q) c C/l ro ::J-Instance 3: Cf) 0 t::'. Cf) Q) Q) For each instance enter value, or "yes" I "no" for: 1 2 3 ~ (.) ::Jc u ro Design yr. headwater WSE 1 ft. below curb top? Q) iii ..... c <( ·-100-yr. max. depth at street crown 2 feet or less? Q) ..... 0 Product of velocity (fps) & depth at crown (ft) = ? E ..... g Is velocity limited per conditions (Table C-11 )? Limit of down stream analysis (feet)? Explain any "no" answers: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage ConceQt and Design Parameters I Continued (Page 4.12) Stormwater Management Concept (continued) . Within Or Serving Subject Property (Phase, or Site) (continued) All Proposed Culverts: For all proposed culvert facilities (except driveway/roadside ditch intersects) provide information requested in next eight boxes. Do culverts and travelways intersect at 90 degrees? Yes No If not, ----identify location(s) and intersect angle(s), and justify the design(s): Does drainage way alignment change within or near limits of culvert and surfaced approaches thereto? __ No --Yes If "yes" identify location(s), describe change(s), and justification: Are flumes or conduit to discharge into culvert barrel(s)? __ No __ Yes If yes, identify location(s) and provide justification: 'O Are flumes or conduit to discharge into or near surfaced approaches to culvert ends? <I) --No --Yes If "yes" identify location(s), describe outfall design treatment(s): :J c: :g 0 ~ (/) t <I) Is scour/erosion protection provided to ensure long term stability of culvert structural > "3 () components, and surfacing at culvert ends? __ Yes __ No If "no" Identify locations and provide justification(s): Will 100-yr flow and spread of backwater be fully contained in street ROW, and/or drainage easements/ ROW? __ Yes --No if not, why not? Do appreciable hydraulic effects of any culvert extend downstream or upstream to neighboring land(s) not encompassed in subject property? --No --Yes If "yes" describe location(s) and mitigation measures: Are all culvert designs and materials in compliance with 8-CS Tech. Specifications? --Yes --No If not, explain in Special Design Section of this Part. STORMWATER DESIGN GUIDELINES Effective February 2007 Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Dra inage Conce~t and Design Parameters I Continued (Page 4.13) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Is a bridge included in plans for subject property project? _L No --Yes If ''yes" provide the following information. Name(s) and functional classification of the roadway(s)? What drainage way(s) is to be crossed? (ii' Q) Cl "C ·;::: co A full report supporting all aspects of the proposed bridge(s) (structural, geotechnical, hydrologic, and hydraulic factors) must accompany this summary report. Is the report provided? --Yes --No If "no" explain: Is a Stormwater Provide a general description of planned techniques: >-Pollution Prevention rock riprap, silt fence installation and inlet protection :!: iii Plan (SW3P) ::J 0 established for .... project construction? Q) ~ --No _L Yes Special Designs -Non-Traditional Methods Are any non-traditional methods (aquatic echosystems, wetland-type detention, natural stream replication, BMPs for water quality, etc.) proposed for any aspect of subject property project? _L No --Yes If ''yes" list general type and location below. .. Provide full report about the proposed special design(s) including rationale for use and expected benefits. Report must substantiate that stormwater management objectives will not be compromised, and that maintenance cost will not exceed those of traditional design solution(s). Is report provided? STORMWATER DESIGN GUIDELINES EffecUve February 2007 Yes ---- Page 22 of 26 No If "no" explain: APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX · APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters J Continued (Page 4.14) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Special Designs -Deviation From B-CS Technical Specifications If any design(s) or material(s) of traditional runoff-handling facilities deviate from provisions of B-CS Technical Specifications, check type facility(ies) and explain by specific detail element. Detention elements __ Drain system elements Channel features ---- --Culvert features --Swales --Ditches --Inlets __ Outfalls __ · Valley gutters __ Bridges (explain in bridge report) In table below briefly identify specific element, justification for deviation(s). Specific Detail Element Justification for Deviation (attach additional sheets if needed) 1) 2) 3) 4) 5) Have elements been coordinated with the City Engineer or her/his designee? For each item above provide "yes" or "no'', action date, and staff name: 1) 2) 3) 4) 5) ' ~· .fl··: Design Parameters --·-~ · . . ' -f:·,, ~ .. .l. •• .:« .... ·, .. ~:.t '.1~· .,.,., Hydrology Yes No Is a map(s) showing all Design Drainage Areas provided? __!f_ -- Briefly summarize the range of applications made of the Rational Formula: Pipe Design, Inlet Design and Gutter Depth Check What is the size and location of largest Design Drainage Area to which the Rational Formula has been applied? 34.73 acres STORMWATER DESIGN GUIDELINES Effective February 2007 Location (or identifier): 301 Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters I Continued (Page 4.15) Design Parameters (continued) '·'· Hydrology (continued) In making determinations for time of concentration, was segment analysis used? No ./ Yes In approximately what percent of Design Drainage Areas? JOO % As to intensity-duration-frequency and rain depth criteria for determining runoff flows, were any criteria other than those provided in these Guidelines used? _:f_ No __ Yes If "yes" identify type of data, source(s), and where applied: For each of the stormwater management features listed below identify the storm return frequencies (year) analyzed (or checked), and that used as the basis for design. Feature Analysis Year(s) Design Year Storm drain system for arterial and collector streets 10& 100 JO Storm drain system for local streets 10& 100 10 Open channels NIA NIA Swale/buried conduit combination in lieu of channel NIA NIA Swales NIA NIA Roadside ditches and culverts serving them NIA NIA Detention facilities: spillway crest and its outfall NIA NIA Detention facilities: outlet and conveyance structure(s) NIA NIA Detention facilities: volume when outlet plugged NIA NIA Culverts serving private drives or streets NIA NIA Culverts serving public roadways NIA NIA Bridges: provide in bridge report. NIA NIA Hydraulics What is the range of design flow velocities as outlined below? Design flow velociti es; Gutters Conduit Culverts Swales Channels Highest (feet per second) 2.96 6.77 NIA NIA NIA Lowest (feet per second) 1.34 0.30 NIA NIA NIA Streets and Storm Drain Systems Provide the summary information outlined below: Roughness coefficients used: For conduit type(s) RCP STORMWATER DESIGN GUIDELINES Effective February 2007 For street gutters: HDPE Page 24 of 26 0.018 Coefficients: 0.013 0.013 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 SECTION IX APPENDIX D-TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce(;!t and Design Parameters I Continued (Page 4.16) Design Parameters (continued) Hydraulics (continued) Street and Storm Drain Systems (continued) For the following, are assumptions other than allowable per Guidelines? Inlet coefficients? _L No Yes Head and friction losses _L No Yes ---- Explain any "yes" answer: In conduit is velocity generally increased in the downstream direction? _L Yes --No Are elevation drops provided at inlets, manholes, and junction boxes? _L Yes --No Explain any "no" answers: Are hydraulic grade lines calculated and shown for design storm? ~ Yes --No For 100-year flow conditions? _L Yes --No Explain any "no" answers: What tailwater conditions were assumed at outfall point(s) of the storm drain system? Identify each location and explain: Yes, the storm drain system was designed taking into account a tail water of 298.0' (10 yr storm) and 299.7' (JOO yr storm). Open Channels If a HEC analysis is utilized, does it follow Sec Vl.F.5.a? __ Yes __ No Outside of straight sections, is flow regime within limits of sub-critical flow? __ Yes __ No If "no" list locations and explain: Culverts If plan sheets do not provide the following for each culvert, describe it here. For each design discharge, will operation be outlet (barrel) control or inlet control? Entrance, friction and exit losses: Bridges Provide all in bridge report STORMWATER DESIGN GUIDELINES Effective February 2007 Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012 - SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concel;!t and Design Parameters I Continued (Page 4.17) Design Parameters (continued) .. Computer Software What computer software has been used in the analysis and assessment of stormwater management needs and/or the development of facility designs proposed for subject property project? List them below, being sure to identify the software name and version, the date of the version, any applicable patches and the publisher Excel spreadsheets, Autodesk Civil 3D Storm Sewer Analysis and Hydroflow Part 5 -Plans and Sl;!ecifications Requirements for submittal of construction drawings and specifications do not differ due to use of a Technical Design Summary Report. See Section Ill, Paragraph C3. Part 6 -Conclusions and Attestation Conclusions ,.. . . ':\' ~ '· Add any concluding informati on here: . . . . . . The storm sewer system and detention facilities are designed m accordance with the BCS Drainage Design Guidelines. 'ft~·· -···· -.o..~ = -Attestation :H: ,,.,;;;,, ·~ Provide attestation to the accuracy and completeness of the foregoing 6 Parts of this Technical Design Summary Drainage Report by signing and sealing below. "This report (plan) for the drainage design of the development named in Part B was prepared by me (or under my supervision) in accordance with provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for t.!J.~~~d drainage impro 'ements have been issued or fall under applicable general ~~-~~00?'~'~o ~ jJ_J_ (Affix Se'f'. :,···· * ····~<!' lt1 \ . I!*: . ·!~ ~o•.,•ooooo•'#Joe•••o••P•90•111~eeo:'ct•~••~ L" >/d p ,/e · / E · ~ JOSEPH P. SCHULTZ ~ 1cens ro ess1ona ng1neer ~OH .. OH .. OOHoe .. H .. UOOU'1eoooo.J! ,~. 6 "I:!;~ State of Texas PE No. 6fB8 °1 STORMWATER DESIGN GUIDELINES Effective February 2007 Page 26 of 26 ~i\1> 5889 / ltJif • •• ~ <;;,,~ • ([,-d!1 ~~ •o/~ I STE~ 0° 00 ~ .# ?. ~li.s:~·~ •••.•••• k,0.a -ZZ-f3 -~, .. '"'iVAL v~l!W' APPENDIX. D: TECH. DESIGN SUMMARY As Revised August 2012