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HomeMy WebLinkAboutDrainage Reportna I DRAINAGE REPORT FOR CARTER'S CROSSING, PHASES 1 & 2 COLLEGE STATION, TEXAS JUNE2006 MBESI# I 000--0072 SUBMITIED BY: McCLURE & BROWNE ENGINEERING/SURVEYING, INC. I 008 Woodcreek Drive, Suite I 03 • College Station, Texas 77845 (979) 693-3838 • Fax: (979) 693-2554 • Email: McClureBrowne@Verizon.net CERTIFICATION Drainage Report for Carter's Crossing Subdivision Phase 1 & 2 MEES!# 1000-0072 I, Jeffery L. Robertson, Registered Professional Engineer No. 94745, State of Texas, certify that this addendum report for the drainage design of Carter's Crossing Subdivision, Phases 1 & 2, was prepared by me in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof. ... ....... ,,,,,,\,, ---'"':.~€.OF r~ ''' -"'~ ········· :.r ....... .::' c-;,' ··"'*'• .. -~U' ., ,,. * .... . .... ic ,, ~* :' ". *~ t'jeFFERv'L'.'A08ER:rsoo'~ ~ ....................................... ~ ~ -0 \ 94745 /,Cf;~ . '/.,~... :'l:O'f~ 10• • N; 11 ~ ... ~1CENS-e,?, .. ~_# ~ •1 ''ISl.s ........... ~~"'.: '"''~a~~~ .... --- SUMMARY This Drainage Report for Carter's Crossing Subdivision analyzes the proposed storm drain and culvert systems in Phases 1 & 2 of the subdivision. It has been determined that the runoff from this site can be released un- detained without causing harmful effects to the downstream property. GENERAL INFORMATION Area encompassed by Phases 1 & 2: Anticipated land use: Anticipated number of lots: Notes on surrounding development: FLOOD HAZARD INFORMATION FEMA FIRM Map#: 48041C0163C Effective Date: July 2, 1992 27. 756 acres Single family residential 72 lots The property is bordered by Raintree Subdivision to the north, undeveloped land to the east and west, and Emerald Forest Subdivision to the South. Comments: No portion of the site is shown to be within the 100-year floodplain, so it is not currently regulated under the National Flood Insurance Program. Applicable Exhibits: A Excerpt of FEMA FIRM DESCRIPTION OF DRAINAGE SYSTEMS Primary System: Secondary System: Drainage Report The site is open with dense vegetation around the creek channels. The site naturally drains to a tributary of Carters Creek, which runs from west to east within the site. Runoff from the residential lots will flow into the streets where it is captured by inlets and conveyed through underground pipes to the existing creek channel. Page 1 of3 Carter's Crossing Subdivision Phases 1 & 2 Applicable Exhibits: B-1 Drainage Area Map (For Detention and Floodplain Calculations) B-2 Drainage Area Map (For Storm Drain Pipe and Inlet Sizing) C-1 Rational Formula Drainage Area Calculations C-2 Inlet Computations C-3 Pipe Size Calculations D-1 SCS Method Runoff Summary D-2 SCS Drainage Area Parameters E-1 HEC-RAS Output Data E-2 HEC-RAS Cross Section Data F-1 Letter of Agreement with Downstream Property Owner DETENTION & FLOODPLAIN ANALYSIS Design Storm: Design Methodology Hydrology: Software Model: Curve Numbers: 100-yr Return Period SCS Method Hydraflow Hydrographs 2002 Impervious Area = 98 Medium Density Residential = 87 Undeveloped Area= 75 SECONDARY STORM DRAIN DESIGN Design Storm: Design Methodology Hydrology: Software Model: 10-yr Return Period Time of Concentration: Rational Formula Excel Spreadsheet 10 min. Runoff Coefficients: Hydraulics: Software Model: Manning's N: 0.40 -Undeveloped area 0.55 -Residential areas 0.90 -Paved areas Manning's Equation Excel Spreadsheet 0.014 (concrete pipe or HDPE pipe) Applicable Exhibits: Addendum C-1 Rational Formula Drainage Area Calculations Addendum C-2 Inlet Computations Addendum C-3 Pipe Size Calculations Addendum C-4 Proposed Culvert Analysis Addendum C-5 Hydraulic Grade Line Calculations (10 yr.) Addendum C-6 Hydraulic Grade Line Calculations (100 yr.) Addendum F-1 Hydraulic Grade Line Schematics DETENTION REQUIREMENTS General Note: Detention for Carter's Crossing Subdivision (all phases) is not needed due to its location in the Carters Crossing Drainage Basin. The pre-and post-development storm flows were calculated to determine the impact on downstream property. A small increase in the runoff and the water surface elevation has been shown. However, the increase is negligible and the down stream property owner has been notified and a written agreement is attached to Drainage Report Carter's Crossing Subdivision Phases 1 & 2 Page 2 of3 this report. The table below shows the results of the analysis at the end of the project (Sta. 3+00). Storm Pre-Dev Post-Dev Event Conditions Conditions 5 229 cfs 242 cfs 10 292 cfs 305 cfs 25 366 cfs 379 cfs 50 419 cfs 431 cfs 100 482 cfs 494 cfs EROSION AND SEDIMENTATION CONTROLS Control Measures: SWPPP: Drainage Report Silt fence Hydromulch seeding Inlet protection Construction entrance/exit The contractor shall be responsible for establishing and maintaining the SWPPP in accordance with TCEQ requirements. Page 3 of3 Carter's Crossing Subdivision Phases I & 2 /\ ,, ' _., ,, NTS EXHIBIT A Flood Insurance Rate Map Excerpt Brazos County, Texas and Incorporated Areas Map Numbers: 48041 C0163C Effective Date: July 2, 1992 c( ~ w c 0 a:: w ..J ..J c( ~ Q. c( LL w 0 I= I-c 0 ..J z c( z c( w z w 0 ~ j!: c( ..J > w :::E ..J z c ~ ~ ~~ iii w ~ WO > >z ~ z a:: ~ c( ~ o~ c ::> c( Q. NO. AC. 0.4 0.66 0.9 ft. 1 1.28 0.00 1.28 0.00 0.70 250.0 3 1.23 0.00 1.23 0.00 0.68 215.0 4 1.22 0.00 1.22 0.00 0.67 97.0 5 5.85 0.00 5.85 0.00 3.22 138.0 6 2.26 0.00 2.26 0.00 1.24 1.0 7 1.39 0.00 1.39 0.00 0.76 1.0 19 8.00 8.00 0.00 0.00 3.20 500.0 20 0.94 0.00 0.94 0.00 0.52 70.0 21 1.59 0.00 1.59 0.00 0.87 152.0 22 0.87 0.00 0.87 0.00 0.48 144.0 23 0.88 0.00 0.88 0.00 0.48 74.0 24 0.59 0.00 0.59 0.00 0.32 77.0 25 0.46 0.00 0.46 0.00 0.25 1.0 26 1.00 0.00 1.00 0.00 0.55 1.0 27 0.29 0.00 0.29 0.00 0.16 1.0 28 0.17 0.00 0.17 0.00 0.09 1.0 29 0.87 0.00 0.87 0.00 0.48 1.0 30 0.81 0.00 0.81 0.00 0.45 1.0 31 0.00 0.00 0.00 0.00 0.00 1.0 32 0.00 0.00 0.00 0.00 0.00 1.0 33 2.30 0.00 2.30 0.00 1.27 1.0 35 0.81 0.00 0.81 0.00 0.45 1.0 EXHIBIT C-1 Rational Formula Drainage Area Calculations Carter's Crossing, Phases 1 & 2 ~ 0 ~ ~ ..J LL 0 0 c ..J ..J z LL LL l'.: ~ ..J a:: j!: a:: ~ ..J 0 ~ ~ ~o 0 u w ..J ::> z ::> ..J ..J w > c( o~ o~ !ti! ii II) N IO 0 LL 0 ::> !:! (J !!! (J ft. ft. ft. ft/s min min In/Hr cfs In/Hr cfs 2.0 150.0 1.0 0.8 8.1 10.0 6.33 4.5 7.7 5.4 2.0 98.0 1.0 0.9 6.1 10.0 6.33 4.3 7.7 5.2 1.0 387.0 4.0 1.5 5.5 10.0 6.33 4.2 7.7 5.2 1.4 861 .6 3.8 1.2 14.2 14.2 5.35 17.2 6.6 21 .1 1.0 1.0 1.0 10.4 0.0 10.0 6.33 7.9 7.7 9.6 1.0 1.0 1.0 10.4 0.0 10.0 6.33 4.8 7.7 5.9 2.0 884.0 5.0 0.8 28.5 28.5 3.58 11 .4 4.5 14.3 0.7 461 .0 2.8 1.3 6.6 10.0 6.33 3.3 7.7 4.0 1.5 250.0 2.0 1.1 5.9 10.0 6.33 5.5 7.7 6.7 1.4 233.0 2.8 1.2 5.2 10.0 6.33 3.0 7.7 3.7 0.7 417.0 5.0 1.7 5.0 10.0 6.33 3.1 7.7 3.7 2.0 280.0 2.5 1.6 3.6 10.0 6.33 2.1 7.7 2.5 1.0 1.0 1.0 10.4 0.0 10.0 6.33 1.6 7.7 1.9 1.0 1.0 1.0 10.4 0.0 10.0 6.33 3.5 7.7 4.2 1.0 1.0 1.0 10.4 0.0 10.0 6.33 1.0 7.7 1.2 1.0 1.0 1.0 10.4 0.0 10.0 6.33 0.6 7.7 0.7 1.0 1.0 1.0 10.4 0.0 10.0 6.33 3.0 7.7 3.7 1.0 1.0 1.0 10.4 0.0 10.0 6.33 2.8 7.7 3.4 1.0 1.0 1.0 10.4 0.0 10.0 6.33 0.0 7.7 0.0 1.0 1.0 1.0 10.4 0.0 10.0 6.33 0.0 7.7 0.0 1.0 1.0 1.0 10.4 0.0 10.0 6.33 8.0 7.7 9.7 1.0 1.0 1.0 10.4 0.0 10.0 6.33 2.8 7.7 3.4 0 IO 0 ... IO N !: (J N (J In/Hr cfs In/Hr cfs 8.6 6.1 9.9 6.9 8.6 5.8 9.9 6.7 8.6 5.8 9.9 6.6 7.4 23.8 8.5 27.2 8.6 10.7 9.9 12.3 8.6 6.6 9.9 7.5 5.1 16.3 5.8 18.7 8.6 4.5 9.9 5.1 8.6 7.6 9.9 8.6 8.6 4.1 9.9 4.7 8.6 4.2 9.9 4.8 8.6 2.8 9.9 3.2 8.6 2.2 9.9 2.5 8.6 4.7 9.9 5.4 8.6 1.4 9.9 1.6 8.6 0.8 9.9 0.9 8.6 4.1 9.9 4.7 8.6 3.8 9.9 4.4 8.6 0.0 9.9 0.0 8.6 0.0 9.9 0.0 8.6 10.9 9.9 12.5 8.6 3.8 9.9 4.4 ~ ~ (J In/Hr cfs 11.1 7.8 11.1 7.5 11.1 7.5 9.6 30.8 11.1 13.9 11 .1 8.5 6.6 21 .3 11.1 5.8 11 .1 9.7 11 .1 5.3 11 .1 5.4 11.1 3.6 11 .1 2.8 11 .1 6.1 11.1 1.8 11 .1 1.0 11 .1 5.3 11.1 5.0 11.1 0.0 11.1 0.0 11.1 14.1 11.1 5.0 0 0 0 0 .... .... (J In/Hr cfs 12.5 8.8 12.5 8.5 12.5 8.4 10.8 34.7 12.5 15.6 12.5 9.6 7.5 24.1 12.5 6.5 12.5 11 .0 12.5 6.0 12.5 6.1 12.5 4.1 12.5 3.2 12.5 6.9 12.5 2.0 12.5 1.2 12.5 6.0 12.5 5.6 12.5 0.0 12.5 0.0 12.5 15.8 12.5 5.6 11/21/2006 10000072-dra.xls Exhibit C-1 rilil • (.!) 0 ~~ 1 3 4 5 6 7 8 20 21 22 23 24 25 26 27 28 29 30 33 35 :s i.. < ~ ~ Q : 'f .: ~ = > i.. o= 0 = ~ i.. = ~ Cl) = = ·e = cfs 6.0 I 6.1 7.0 I 5.8 SB I 5.8 6.0 I 23.8 7.0 I 10.7 NA I 6.6 NA I 6.8 23.0 I 4.5 22.0 I 7.6 24.0 I 4.1 na I 4.2 26.0 I 2.8 NA I 3.2 NA I 6.9 30.0 I 1.4 29.0 I 0.8 25.0 I 4.1 26.0 I 3.8 NA I 10.9 na I 3.8 EXHIBITC-2 INLET COMPUTATIONS Carter's Crossing, Phases 1 & 2 i.. ~ > 0 t-i. = u 0 ~ :s .... = 0 '3 Q ~ .c: .... "O ~ .... ~ f:! .... rl:1 t i.. ~ -"O ,o ~ o" --·; ~ c:r c. ~ Q ~ 00 o.o I 6.1 I 271 0.6% o.o I 5.8 I 271 0.6% o.o I 5.8 I 271 0.5% o.o I 23.8 I 27 I 9.2% 17.6 I 28.3 I 271 13.1% 5.0 I 11.6 I 271 2.2% o.o I 6.8 I 27 I 0.8% o.o I 4.5 I 271 0.3% o.o I 7.6 I 271 0.9% o.o I 4.1 I 271 0.3% o.o I 4.2 I 27 I 0.3% o.o I 2.8 I 271 0.1% o.o I 3.2 I 381 0.4% o.o I 6.9 I 381 1.7% o.o I 1.4 I 381 0.1% 0.0 I 0.8 I 38 I 0.0% o.o I 4.1 I 381 0.6% o.o I 3.8 I 38 I 0.5% 0.0 I 10.9 I 271 2.0% o.o I 3.8 I 271 0.2% ~ z ~ :s ~ :s .... = 0 '3 Q ~ 1 I 6.1 3 I 5.8 4 I 5.8 5 123.8 6 I 28.3 7 I 11.6 8 I 6.8 20 I 4.5 21 I 7.6 22 I 4.1 23 I 4.2 24 I 2.8 25 I 3.2 26 I 6.9 27 I 1.4 28 I 0.8 29 I 4.1 30 I 3.8 33 110.9 35 I 3.8 DESCRIPTION Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Inlet on Grade Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet r-.; .J i.. ~ ~ ~ "° c:r ~ .J "O ~ "O ·~ i.. ~ .J Curb Inlet cfs I ft I ft 2.33 I 2.60 I 5 2.33 I 2.50 I 5 2.33 I 2.48 I 5 0.62138.491 10 2.33112.141 10 2.33 I 4.97 I 5 2.33 I 2.91 I 5 2.33 I 1.91 I 5 2.33 I 3.23 I 5 2.33 I 1.77 I 5 2.33 I 1.79 I 5 2.33 I 1.20 I 5 2.33 I 1.36 I 5 2.33 I 2.95 I 5 2.33 I 0.59 I 5 2.33 I 0.35 I 5 2.33 I 1.77 I 5 2.33 I 1.65 I 5 2.33 I 4.68 I 5 2.33 I 1.65 I 5 i.. .c: • ~ .... ~ > c. . 0 ~ rl:1 t-= t t.. ] ~ = "O • u = ~ 0 :,, ~ ] i.. .... = c:r ~ = ~ i.. < ] "O ·;: Q i.. ~ 5 i.. < Grate Inlet 0 0 0 18 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ft I cfs I sq-ft I sq-ft 11/21/2006 10000072-dra.xls Exhibit C-2 • e 0 < r.. u 0 z ~ -00 r.. g i-:i < = ~ .~ r.. ~ 0 0 "' u Q.I ~ r.. r.. r.. ~ # # Ac. min yr 1 5.1 0.7 10.0 10 3 7 0.7 10.0 10 4 6 0.7 10.0 10 5 5.1 3.2 14.2 10 5.1 6 3.9 14.5 10 6 6.1 5.8 15.0 10 6.1 6.2 5.8 15.5 10 6.2 7 5.8 16.0 10 7 8 7.3 16.6 10 8 Out 8.1 17.0 10 19 28 3.2 28.5 10 20 21 0.5 10.0 10 21 22 1.4 10.2 10 22 24 1.9 11 .0 10 23 24 0.5 10.0 10 24 26 2.7 11.4 10 25 Out 3.5 12.2 100 26 25 3.2 11 .6 100 27 28 0.2 10.0 10 28 Out 3.5 28.6 10 33 Out 1.3 10.0 10 35 Out 0.4 10.0 10 *Includes 33% Flow Increase for pipe sizes <27" dia. EXHIBIT C-3 PIPE SIZE CALCULATIONS Carter's Crossing, Phases 1 & 2 .~ I "' Q « Q.I « ~ ·-Q.I Q.I "' Q. Q. Q.I "' "O ~ Q.I it .s Q.I Q. r'-l -"O ,_ "' it = Q.I Q.I = -~ 0 .... "'« .... "O ~ 0 ·-~ .e, ~ ~ t: =s 0 "O 0 0 ~ ·c N =-< ii: ~ ;;;;;> ~ z ~ r'-l cfs cfs # cfs % .. 6.1 7.9 1 7.9 0.48 18 5.8 7.6 1 7.6 0.44 18 5.8 7.5 1 7.5 0.44 18 23.8 30.9 1 30.9 1.58 24 28.7 28.7 1 28.7 0.41 30 42.0 42.0 1 42.0 0.34 36 41 .3 41 .3 1 41 .3 0.32 36 40.6 40.6 1 40.6 0.31 36 49.8 49.8 1 49.8 0.47 36 54.5 54.5 1 54.5 0.56 36 16.3 21 .1 1 21 .1 0.74 24 4.5 5.8 1 5.8 0.26 18 11.9 15.5 1 15.5 0.40 24 15.5 20.2 1 20.2 0.67 24 4.2 5.4 1 5.4 0.23 18 21 .8 21 .8 1 21.8 0.24 30 40.1 40.1 1 40.1 0.31 36 38.1 38.1 1 38.1 0.28 36 1.4 1.8 1 1.8 0.02 18 17.5 22.8 1 22.8 0.86 24 10.9 14.2 1 14.2 0.33 24 3.8 5.0 1 5.0 0.19 18 -See Plan & Profile for pipe slope used (Pipe slope >or= Friction slope) = r.. ~ ~ z ~ ~ > i-:i fps ' 4.5 32 4.3 30 4.3 45 9.8 182 5.8 183 5.9 183 5.8 184 5.7 185 7.0 185 7.7 30 6.7 41 3.3 32 4.9 246 6.4 175 3.1 30 4.4 39 5.7 38 5.4 200 1.0 51 7.2 52 4.5 50 2.8 50 Q.I .§ r.. 'il ~ ,_ r.. min 0.12 0.12 0.18 0.31 0.52 0.51 0.53 0.54 0.44 0.06 0.10 0.16 0.83 0.46 0.16 0.15 0.11 0.62 0.84 0.12 0.18 0.29 "O r.. = ~ ~ ~ @ ~ ~ ~ u = r.. min ' ' 10.12 10.12 10.18 14.49 15.01 15.52 16.05 16.59 17.03 17.09 28.64 10.16 10.99 11.45 10.16 11 .60 12.33 12.21 10.84 28.76 10.18 10.29 11121/2006 10000072-dra.xls Exhibit C-3 <( ;: w c 0 D: w ...I ...I <( ~ Q. <( u.. w 0 j:: I-c C) D: ...I z <( z <( <( w z w 0 <( ::c ...I > w :!ii ...I ...I I-z <( w <( c w <( D: C) ~ iii I-cw > I-Wz 0 ~~ w <( 0 >w c I-D: Q. I-0....1 NO. AC. 0.4 0.55 0.9 ft. 1 1.28 0.00 1.28 0.00 0.70 250.0 3 1.23 0.00 1.23 0.00 0.68 215.0 4 1.22 0.00 1.22 0.00 0.67 97.0 5 5.85 0.00 5.85 0.00 3.22 138.0 5.1 0.00 0.00 0.00 0.00 0.00 1.0 6 2.26 0.00 2.26 0.00 1.24 1.0 7A 1.00 0.00 1.00 0.00 0.55 1.0 78 0.39 0.00 0.39 0.00 0.21 1.0 8A 0.91 0.00 0.91 0.00 0.50 1.0 88 0.52 0.00 0.52 0.00 0.29 1.0 19 8.00 8.00 0.00 0.00 3.20 500.0 20 0.94 0.00 0.94 0.00 0.52 70.0 21 1.59 0.00 1.59 0.00 0.87 152.0 22 0.87 0.00 0.87 0.00 0.48 144.0 23 0.88 0.00 0.88 0.00 0.48 74.0 24 0.59 0.00 0.59 0.00 0.32 77.0 25A 0.21 0.00 0.21 0.00 0.12 1.0 258 0.25 0.00 0.25 0.00 0.14 1.0 26A 0.21 0.00 0.21 0.00 0.12 1.0 268 0.79 0.00 0.79 0.00 0.43 1.0 27 0.29 0.00 0.29 0.00 0.16 1.0 28 0.17 0.00 0.17 0.00 0.09 1.0 29 0.87 0.00 0.87 0.00 0.48 1.0 30 0.81 0.00 0.81 0.00 0.45 1.0 33 2.30 0.00 2.30 0.00 1.27 1.0 35 0.81 0.00 0.81 0.00 0.45 1.0 EXHIBIT C-1 Rational Formula Drainage Area Calculations Carter's Crossing, Phases 1 & 2 ;: 0 ;: ;: ...I u.. 0 0 c ...I ...I z u.. u.. ~ ~ D: ::c D: 0 w I-w 0 I-0 D: ...I I: C) I: ...I 0 I-c.i w ...I ...I w > <( :::> z :::>...I w iii !/) N .,, 0 u.. C) ~ C) ~ > 0 :::> £! a .,, a ft. ft. ft. Ws min min In/Hr cfs In/Hr cfs 2.0 150.0 1.0 0.8 8.1 10.0 6.33 4.5 7.7 5.4 2.0 98.0 1.0 0.9 6.1 10.0 6.33 4.3 7.7 5.2 1.0 387.0 4.0 1.5 5.5 10.0 6.33 4.2 7.7 5.2 1.4 861 .6 3.8 1.2 14.2 14.2 5.35 17.2 6.6 21.1 1.0 1.0 1.0 10.4 0.0 10.0 6.33 0.0 7.7 0.0 1.0 1.0 1.0 10.4 0.0 10.0 6.33 7.9 7.7 9.6 1.0 1.0 1.0 10.4 0.0 10.0 6.33 3.5 7.7 4.2 1.0 1.0 1.0 10.4 0.0 10.0 6.33 1.4 7.7 1.7 1.0 1.0 1.0 10.4 0.0 10.0 6.33 3.2 7.7 3.9 1.0 1.0 1.0 10.4 0.0 10.0 6.33 1.8 7.7 2.2 2.0 884.0 5.0 0.8 28.5 28.5 3.58 11.4 4.5 14.3 0.7 461.0 2.8 1.3 6.6 10.0 6.33 3.3 7.7 4.0 1.5 250.0 2.0 1.1 5.9 10.0 6.33 5.5 7.7 6.7 1.4 233.0 2.8 1.2 5.2 10.0 6.33 3.0 7.7 3.7 0.7 417.0 5.0 1.7 5.0 10.0 6.33 3.1 7.7 3.7 2.0 280.0 2.5 1.6 3.6 10.0 6.33 2.1 7.7 2.5 1.0 1.0 1.0 10.4 0.0 10.0 6.33 0.7 7.7 0.9 1.0 1.0 1.0 10.4 0.0 10.0 6.33 0.9 7.7 1.1 1.0 1.0 1.0 10.4 0.0 10.0 6.33 0.7 7.7 0.9 1.0 1.0 1.0 10.4 0.0 10.0 6.33 2.7 7.7 3.3 1.0 1.0 1.0 10.4 0.0 10.0 6.33 1.0 7.7 1.2 1.0 1.0 1.0 10.4 0.0 10.0 6.33 0.6 7.7 0.7 1.0 1.0 1.0 10.4 0.0 10.0 6.33 3.0 7.7 3.7 1.0 1.0 1.0 10.4 0.0 10.0 6.33 2.8 7.7 3.4 1.0 1.0 1.0 10.4 0.0 10.0 6.33 8.0 7.7 9.7 1.0 1.0 1.0 10.4 0.0 10.0 6.33 2.8 7.7 3.4 0 .,, 0 ..... .,, N ..... a N a In/Hr cfs In/Hr cfs 8.6 6.1 9.9 6.9 8.6 5.8 9.9 6.7 8.6 5.8 9.9 6.6 7.4 23.8 8.5 27.2 8.6 0.0 9.9 0.0 8.6 10.7 9.9 12.3 8.6 4.7 9.9 5.4 8.6 1.9 9.9 2.1 8.6 4.3 9.9 4.9 8.6 2.5 9.9 2.8 5.1 16.3 5.8 18.7 8.6 4.5 9.9 5.1 8.6 7.6 9.9 8.6 8.6 4.1 9.9 4.7 8.6 4.2 9.9 4.8 8.6 2.8 9.9 3.2 8.6 1.0 9.9 1.1 8.6 1.2 9.9 1.4 8.6 1.0 9.9 1.1 8.6 3.8 9.9 4.3 8.6 1.4 9.9 1.6 8.6 0.8 9.9 0.9 8.6 4.1 9.9 4.7 8.6 3.8 9.9 4.4 8.6 10.9 9.9 12.5 8.6 3.8 9.9 4.4 0 0 .,, .,, a In/Hr cfs 11 .1 7.8 11 .1 7.5 11 .1 7.5 9.6 30.8 11 .1 0.0 11.1 13.9 11.1 6.1 11.1 2.4 11 .1 5.6 11.1 3.2 6.6 21 .3 11.1 5.8 11.1 9.7 11.1 5.3 11 .1 5.4 11.1 3.6 11 .1 1.3 11 .1 1.5 11 .1 1.3 11.1 4.8 11 .1 1.8 11 .1 1.0 11.1 5.3 11.1 5.0 11 .1 14.1 11.1 5.0 0 0 0 0 a !: In/Hr cfs 12.5 8.8 12.5 8.5 12.5 8.4 10.8 34.7 12.5 0.0 12.5 15.6 12.5 6.9 12.5 2.7 12.5 6.3 12.5 3.6 7.5 24.1 12.5 6.5 12.5 11.0 12.5 6.0 12.5 6.1 12.5 4.1 12.5 1.4 12.5 1.7 12.5 1.4 12.5 5.4 12.5 2.0 12.5 1.2 12.5 6.0 12.5 5.6 12.5 15.8 12.5 5.6 6/16/2006 10000072-dra.xls Exhibit C-1 ~ . C-' 0 ~~ ~~ 3 4 5 6 78 BB 19 20 21 22 23 24 258 268 27 28 29 30 33 35 EXHIBIT C-2 INLET COMPUTATIONS Carter's Crossing, Phases 1 & 2 ~ ~ .. < ~ ~ 0 ';Jl '€ .s ~ ~ .... .. o~ 0 ~ ~ .. ~ ~ t){) ~ = ... ~ .. ~ cfs .. ~ 0 Q .. ~ u 0 tl "2 ~ .... ~ 0 -; .... 0 ~ -= .... ::: ~ .... ~ ~ .. .... rJJ. .... ~ ~ .... rJJ. "O :;--~ Q'---·; ~ Q" c. ~ 0 ~ 00 6.0 I 6.1 I 0.0 I 6.1 I 271 0.6% 7A I 5.8 I 0.0 I 5.8 I 271 0.6% 8B I 5.8 I 0.0 I 5.8 I 271 0.5% 6.0 I 23.8 I 0.0 I 23.8 I 271 9.2% 7B 10.7 17.6 I 28.3 I 27 13.1% NA 1.9 5.0 I 6.8 I 27 0.8% NA 2.5 o.o I 2.5 I 27 0.1% NA 16.3 0.0 I 16.3 I 27 4.3% 23.0 4.5 0.0 I 4.5 I 27 0.3% 22.0 7.6 0.0 I 7.6 I 27 0.9% 24.0 4.1 o.o I 4.1 I 27 0.3% na 4.2 0.0 I 4.2 I 27 0.3% 26B 2.8 0.0 I 2.8 I 27 0.1% NA 1.2 0.0 I 1.2 I 38 0.1% NA 5.4 0.0 I 5.4 I 38 1.1% 30.0 1.4 o.o I 1.4 I 38 0.1% 29.0 0.8 o.o I 0.8 I 38 0.0% 25B 4.1 o.o I 4.1 I 38 0.6% 26B 3.8 0.0 I 3.8 I 38 0.5% NA 10.9 o.o I 10.9 I 27 2.0% 26B 3.8 0.0 I 3.8 I 27 0.2% Q z tl "2 ~ .... ~ "2 ~ .... ~ 0 -~ .... 0 ~ 1 I 6.1 3 I 5.8 4 I 5.8 5 123.8 6 I 28.3 7B 111.6 8B I 6.8 19 I 16.3 20 I 4.5 21 I 7.6 22 I 4.1 23 I 4.2 24 I 2.8 25BI 2.2 26BI 6.4 27 I 1.4 28 I 0.8 29 I 4.1 30 I 3.8 33 I 10.9 35 I 3.8 DESCRIPTION Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Inlet on Grade Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Recessed Low Point Inlet Rece~sed Low Point Inlet Recessed Low Point Inlet ~ .J .. ~ ~ ~ u -0 Q" ~ .J "O ~ "O ·;;: 0 .. ~ .J Curb Inlet cfs I ft I ft 2.33 I 2.60 I 5 2.33 I 2.50 I 5 2.33 I 2.48 I 5 0.62138.491 10 2.33112.141 10 2.33 I 4.97 I 5 2.33 I 2.91 I 5 2.33 I 6.97 I 10 2.33 I 1.91 I 5 2.33 I 3.23 I 5 2.33 I 1.77 I 5 2.33 I 1.79 I 5 2.33 I 1.20 I 5 2.33 I 0.94 I 5 2.33 I 2.76 I 5 2.33 I 0.59 I 5 2.33 I 0.35 I 5 2.33 I 1.77 I 5 2.33 I 1.65 I 5 2.33 I 4.68 I 5 2.33 I 1.65 I 5 .. -= . ~ .... ~ .... c. . 0 ~ rJJ. >. ~ ~ 1.· "O ~ .. ~ . ~ "O ~ u = < 0 ~ u "O ~ .. ·; Q" ~ ~ ~ ~ .. < "O ~ "O ·;;: 0 .. ~ ~ ~ .. < Grate Inlet 0 0 0 18 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ft I cfs I sq-ft I sq-ft 6/16/2006 10000072-dra.xls Exhibit C-2 E 0 < ~ u 0 z ~ ..... r'1 ~ ~ ~ z < c: ~ .... ~ .::.0 ~ 0 0 ~ z u Cl.I .... ~ ~ ~ ~ # # Ac. min yr 1 5.1 0.7 10.0 10 3 78 0.7 10.0 10 4 6 0.7 10.0 10 5 5.1 3.2 14.2 10 5.1 6 3.9 14.5 10 6 78 5.8 15.0 10 78 88 7.3 15.5 10 88 Out 8.1 15.9 10 19 28 3.2 28.5 10 20 21 0.5 10.0 10 21 22 1.4 10.2 10 22 24 1.9 11.0 10 23 24 0.5 10.0 10 24 268 2.7 11.4 10 258 Out 3.5 12.2 10 268 258 3.2 11.6 100 27 28 0.2 10.0 10 28 Out 3.5 28.6 10 29 Out 0.5 10.0 10 30 Out 0.4 10.0 10 33 Out 1.3 10.0 10 35 Out 0.4 10.0 10 'Includes 33% Flow Increase for pipe sizes <27" dia. EXHIBIT C-3 PIPE SIZE CALCULATIONS Carter's Crossing, Phases 1 & 2 Si> ·-Si> "' ~ "' Cl.I ~ ·-Cl.I Cl.I ~ 0. 0. Cl.I ~ "O ~ Cl.I l:i:; 0 Cl.I en ..... "O 0. ·-... ~ Cl.I ~ Cl.I = = ..... ~ .:; . _, ~"' .... "O if; .2., if; 0 if; ..... ~ u co: 0 "O 0 0 £ ·c N c: -.... ;;;i ~ < ii: z ~ ~ r'1 cfs cfs # cfs % II 6.1 7.9 1 7.9 0.48 18 5.8 7.6 1 7.6 0.44 18 5.8 7.5 1 7.5 0.44 18 23.8 30.9 1 30.9 1.58 24 28.7 28.7 1 28.7 0.41 30 42.0 42.0 1 42.0 0.34 36 51.5 51.5 1 51.5 0.50 36 56.3 56.3 1 56.3 0.60 36 16.3 21.1 1 21.1 0.74 24 4.5 5.8 1 5.8 0.26 18 11.9 15.5 1 15.5 0.40 24 15.5 20.2 1 20.2 0.67 24 4.2 5.4 1 5.4 0.23 18 21.8 21.8 1 21.8 0.24 30 27.6 35.8 1 35.8 9.86 18 38.1 38.1 1 38.1 0.28 36 1.4 1.8 1 1.8 0.02 18 17.5 22.8 1 22.8 0.86 24 4.1 5.4 1 5.4 0.22 18 3.8 3.8 1 3.8 0.00 36 10.9 14.2 1 14.2 0.33 24 3.8 5.0 1 5.0 0.19 18 •• See Plan & Profile for pipe slope used (Pipe slope >or= Friction slope) Cl.I e = E::: ~ ~ ~ ~ z ~ ~ ~ ... ~ ~ ~ fps ' min 4.5 32 0.12 4.3 30 0.12 4.3 45 0.18 9.8 182 0.31 5.8 183 0.52 5.9 183 0.51 7.3 185 0.42 8.0 30 0.06 6.7 41 0.10 3.3 32 0.16 4.9 246 0.83 6.4 175 0.46 3.1 30 0.16 4.4 39 0.15 20.3 38 0.03 5.4 200 0.62 1.0 51 0.84 7.2 52 0.12 3.0 53 0.29 0.5 54 1.65 4.5 50 0.18 2.8 50 0.29 "O ~ = = ~ ~ ~ @ ~ .... ~ ~ u ~ = min ' ' 10.12 10.12 10.18 14.49 15.01 15.52 15.95 16.01 28.64 10.16 10.99 11.45 10.16 11.60 12.25 12.21 10.84 28.76 10.29 11.65 10.18 10.29 6/16/2006 10000072-dra.xls Exhibit C-3 EXHIBIT D-1 SCS Method Runoff Summary Hydrograph Return Period Recap Page1 Hyd. Hydrograph Inflow Peak outflow (cfs) Hydrograph No. type Hyd(s) description (origin) 1-Yr 2·Yr S·Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr 1 SCS Runoff --51.33 -82.80 105.49 132.10 151 .14 173.95 Pre-Developed DA #1 2 SCS Runoff --40.16 -66.58 85.81 108.49 124.75 144.29 Pr&-Developed D.A. #2. 3 SCS Runoff --34.62 -54.23 68.22 84.55 96.19 110.12 Pre-Developed D .A. #3 4 scs Runoff --18.41 -29.56 37.59 47.00 53.72 61 .77 Pre-Developed DA #4 5 Combine 1, 2, -89.97 -145.93 186.38 234.44 268.85 310.14 Pr&-Developed Appomattox Drive 6 Combine 3, 5 -124.44 -199.75 254.60 318.99 365.05 420.26 7 Combine 4,6 -· 142.83 -229.32 292.19 365.99 418.76 482.04 Pre-Oeveloped Tie to Carters Creek Fl 8 SCS Runoff --51.33 -82.80 105.49 132.10 151.14 173.95 Post-Developed D.A. #1 9 SCS Runoff --45.48 -70.66 68.57 109.45 124.33 142.12 Posl-Oeveloped DA #2 10 SCS Runoff --42.20 -63.81 79.05 96.76 109.35 124.40 Post-Developed DA #3 11 SCS Runoff --18.41 -29.56 37.59 47.00 53.72 61.77 Post-Developed DA #4 12 Combine 8,9, -96.58 -152.77 193.00 240.07 273.66 313.90 Post-Developed Appomallox Drive 13 Combine · 10, 12 -136.22 -21286 267.69 331.74 377..43 432.14 14 Combine 11 , 13 -154.81 -242.43 305.27 378.74 431.15 493.92 Post-Oevetoped rie to carters Creek F Proj. file: 10000072-RAS.gpw I Run date: 06-16-2006 Hydratlow Hydrographs by lntelisollle General ~ r/.J ~3 t5 5 ....:l z~ g; > J:,I.l J:,I.l ~< Clg < J:,I.l < ~ §~ ~~ ~ r/.J 3~ # ACRES ACRES ACRES DA 1 pre 38 .67 13.50 0.00 DA 2 pre 29.88 1.30 0.00 DA 3 pre 10.10 0.00 0.00 DA 4 pre 9.10 0.00 0.00 DA 1 post 38.67 13.50 0.00 DA 2 post 11.30 1.30 0.00 DA 3 post 1.87 0.00 0.00 DA 4 post 9.10 0.00 0.00 Exhibit D-2 Drainage Area Parameters ~ ~~ 3 ~ ~~~ r/.J u ~ J:,I.l ~I ~~i r/.J := Cl) t§ ~ 0 < < -z ~ ~ ~ '-I. J:,I.l 5:l ~ 00 C2 0 ~ a4 u ACRES ACRES ACRES ACRES ACRES MILES 0.00 0.00 0.00 0.00 52.17 0.0815 6.05 0.00 0.00 0.00 37.23 0.0582 19.00 0.00 0.00 0.00 29.10 0.0455 7.67 0.00 0.00 0.00 16.77 0.0262 0.00 0.00 0.00 0.00 52.17 0.0815 24.64 0.00 0.00 0.00 37.24 0.0582 27.23 0.00 0.00 0.00 29.10 0.0455 7.67 0.00 0.00 0.00 16.77 0.0262 J:,I.l ~ E-< t5 ~ g: ~ r/.J LENGTH DROP Fr/FT 2492 17 0.007 1576 15 0.010 2450 19 0.008 2241 19 0.008 2492 17 0.007 1576 15 0.010 2450 19 0.008 2241 19 0.008 Existing Cond. PLAN 1 ~ # 80.2 77.6 82.8 80 .5 80 .2 83 .6 86.2 80.5 c.::i < ....:l HOURS 0.79 0.50 0.67 0.65 0.79 0.42 0.60 0.65 Exhibit D-2 Drainage Area Parameters 1000-0072 lag-new .xis EXHIBIT E-1 HEC-RAS DATA (Carter's Crossing Subdivision) HEC-RAS Plan: Plan 01 River. Carter's Creek T Reach: CCT Reach River Sta Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude #Chi (cfs) (ft) (ft) (ft) (ft) (ft/ft) CCT 2550 174 255 257.85 257.85 258.63 0.028324 CCT 2550 174 255 257.85 257.85 258.63 0.028324 CCT 2312 174 252 256.02 256.17 0.003116 CCT 2312 174 252 256.05 256.19 0.003011 CCT 1930 310 250 255.66 255.71 0.000746 CCT 1930 31 4 250 255.69 255.74 0.000736 CCT 1900 310 249 255 252.42 255.1 0.001196 CCT 1900 314 249 255.05 252.44 255.14 0.001163 CCT 1850 Culvert CCT 1800 31 0 249 253.79 254.06 0.004663 CCT 1800 31 4 249 253.81 254.09 0.004671 CCT 1275 420 248 251 .46 251 .59 0.003936 CCT 1275 432 248 251 .49 251 .62 0.003913 CCT 941 420 246.51 250.4 250.5 0.003128 CCT 941 432 246.51 250.43 250.53 0.003137 CCT 600 420 243.26 247.74 247.74 248.15 0.016319 CCT 600 432 243.26 247.76 247.76 248.18 0.016487 CCT 300 482 242.95 246.15 244.88 246.2 0.001637 CCT 300 494 242.95 246.18 244.89 246.22 0.001646 CCT 0 482 243 244.73 244.73 244.95 0.024082 CCT 0 494 243 244.73 244.73 244.96 0.025167 HEC-RAS Results showing pre and post developed conditions for 100 year storm event. (ft/s) (sq ft) 7.19 26.07 7.19 26.07 3.54 81 .29 3.49 82.73 2.3 290.88 2.29 297.38 2.73 180.95 2.71 185.42 4.4 88.3 4.42 89.38 3.43 208.91 3.45 214.5 3.61 243.12 3.64 248.52 6.95 127.93 7.02 130.59 1.65 291 .5 1.67 296.02 4.95 197.46 5.06 197.92 (ft) 18.95 0.94 18.95 0.94 59.67 0.33 60.42 0.32 208.67 0.18 212.71 0.18 100 0.22 100 0.22 53.55 0.42 54.16 0.42 184.43 0.38 186.1 0.38 172.96 0.35 174.73 0.35 139.16 0.67 139.87 0.67 180.23 0.23 181.26 0.23 446.75 0.83 447.33 0.84 EXHIBIT E-1 6/16/2006 HECRAS-Output EXHIBIT E-2 Plan: Plan 01 River: Carter's Creek T Reach:CCT Riv Sta: 2550 Profile: PF 1 E.G. Elev (ft) 258.63 Element Left OB Channel Right OB Vel Head (ft) 0.78 Wt. n-Val. 0.075 0.05 0.075 W.S. Elev (ft) 257.85 Reach Len. (ft) 238 238 238 Crit W.S. (ft) 257.85 Flow Area (sq ft) 1.44 23 .54 1.08 E.G. Slope (ft/ft) 0.028324 Area (sq ft) 1.44 23 .54 1.08 Q Total (cfs) 174 Flow (cfs) 2.66 169.37 1.97 Top Width (ft) 18.95 Top Width (ft) 3.4 13 2.55 Vel Total (ft/s) 6.68 Avg . Vel. (ft/s) 1.85 7.19 1.82 Max Chi Dpth (ft) 2.85 Hydr. Depth (ft) 0.42 1.81 0.42 Conv. Total (cfs) 1033.9 Conv. (cfs) 15.8 1006.4 11 .7 Length Wtd. (ft) 238 Wetted Per. (ft) 3.5 13.64 2.69 Min Ch El (ft) 255 Shear (lb/sq ft) 0.73 3.05 0.71 Alpha 1.13 Stream Power (lb/ft s) 1.34 21 .95 1.3 Frctn Loss (ft) 1.67 Cum Volume (acre-ft) 5.01 6.1 2.97 C & E Loss (ft) 0.19 Cum SA (acres) 4.65 2.5 4.19 Plan: Plan 01 River: Carter's Creek T Reach:CCT Riv Sta: 2550 Profile: PF 2 E.G. Elev (ft) 258.63 Element Left OB Channel Right OB Vel Head (ft) 0.78 Wt. n-Val. 0.075 0.05 0.075 W.S. Elev (ft) 257.85 Reach Len. (ft) 238 238 238 Crit W.S. (ft) 257.85 Flow Area (sq ft) 1.44 23.54 1.08 E.G. Slope (ft/ft) 0.028324 Area (sq ft) 1.44 23.54 1.08 Q Total (cfs) 174 Flow (cfs) 2.66 169.37 1.97 Top Width (ft) 18.95 Top Width (ft) 3.4 13 2.55 Vel Total (ft/s) 6.68 Avg. Vel. (ft/s) 1.85 7.19 1.82 Max Chi Dpth (ft) 2.85 Hydr. Depth (ft) 0.42 1.81 0.42 Conv. Total (cfs) 1033.9 Conv. (cfs) 15.8 1006.4 11 .7 Length Wtd. (ft) 238 Wetted Per. (ft) 3.5 13.64 2.69 Min Ch El (ft) 255 Shear (lb/sq ft) 0.73 3.05 0.71 Alpha 1.13 Stream Power (lb/ft s) 1.34 21.95 1.3 Frctn Loss (ft) 1.63 Cum Volume (acre-ft) 5.15 6.17 3.06 C & E Loss (ft) 0.19 Cum SA (acres) 4.68 2.51 4.25 Plan: Plan 01 River: Carter's Creek T Reach:CCT Riv Sta: 1930 Profile: PF 1 E.G. Elev (ft) 255.71 Element Vel Head (ft) 0.05 Wt. n-Val. W.S. Elev (ft) 255.66 Reach Len. (ft) Crit W.S. (ft) Flow Area (sq ft) E.G. Slope (ft/ft) 0.000746 Area (sq ft) Q Total (cfs) 310 Flow (cfs) Top Width (ft) 208.67 Top Width (ft) Vel Total (ft/s) 1.07 Avg. Vel. (ft/s) Max Chi Dpth (ft) 5.66 Hydr. Depth (ft) Conv. Total (cfs) 11349.4 Conv. (cfs) Length Wtd. (ft) 655 Wetted Per. (ft) Min Ch El (ft) I 250 Shear (lb/sq ft) Alpha 2.79 Stream Power (lb/ft s) Frctn Loss (ft) 0.61 Cum Volume (acre-ft) C & E Loss (ft) 0 Cum SA (acres) Left OB 0.075 655 151 .17 151 .17 109.26 97.85 0.72 1.54 4000.1 97.94 0.07 0.05 4.25 4.13 Channel Right OB 0.05 0.075 655 655 75.92 63 .79 75 .92 63.79 174.5 26.24 15 95.82 2.3 0.41 5.06 0.67 6388.6 960.7 15.94 96.24 0.22 0.03 0.51 0.01 5.45 2.46 2.33 3.5 EXHIBIT E-2 6/16/2006 HECRAS-Cross Section-Output EXHIBIT E-2 Plan: Plan 01 River: Carter's Creek T Reach:CCT Riv Sta: 1930 Profile: PF 2 E.G. Elev (ft) 255.74 Element Left OB Channel Right OB Vel Head (ft) 0.05 Wt. n-Val. 0.075 0.05 0.075 W .S. Elev (ft) 255.69 Reach Len. (ft) 655 655 655 Crit W.S. (ft) Flow Area (sq ft) 154.2 76.39 66.79 E.G. Slope (fUft) 0.000736 Area (sq ft) 154.2 76.39 66.79 Q Total (cfs) 314 Flow (cfs) 111.43 175.03 27.54 Top Width (ft) 212.71 Top Width (ft) 98.77 15 98.94 Vel Total (ft/s) 1.06 Avg. Vel. (ft/s) 0.72 2.29 0.41 Max Chi Dpth (ft) 5.69 Hydr. Depth (ft) 1.56 5.09 0.68 Conv. Total (cfs) 11578 Conv. (cfs) 4108.9 6453.6 1015.5 Length Wtd. (ft) 655 Wetted Per. (ft) 98.86 15.94 99.36 Min Ch El (ft) 250 Shear (lb/sq ft) 0.07 0.22 0.03 Alpha 2.8 Stream Power (lb/ft s) 0.05 0.5 0.01 Frctn Loss (ft) 0.6 Cum Volume (acre-ft) 4.37 5.51 2.53 C & E Loss (ft) 0 Cum SA (acres) 4.15 2.34 3.54 Plan: Plan 01 River: Carter's Creek T Reach:CCT Riv Sta: 1275 Profile: PF 1 E.G. Elev (ft) 251.59 Element Left OB Channel Right OB Vel Head (ft) 0.13 Wt. n-Val. 0.075 0.05 0.075 W .S. Elev (ft) 251.46 Reach Len. (ft) 309 309 309 Crit W .S. (ft) Flow Area (sq ft) 94 80.8 34.11 E.G. Slope (ft/ft) 0.003936 Area (sq ft) 94 80.8 34.11 Q Total (cfs) 420 Flow (cfs) 109.95 276.98 33.07 Top Width (ft) 184.43 Top Width (ft) 102.94 32 49.5 Vel Total (ft/s) 2.01 Avg. Vel. (ft/s) 1.17 3.43 0.97 Max Chi Dpth (ft) 3.46 Hydr. Depth (ft) 0.91 2.52 0.69 Conv. Total (cfs) 6694.8 Conv. (cfs) 1752.6 4415.1 527.2 Length Wtd. (ft) 309 Wetted Per. (ft) 102.96 32.41 49.52 Min Ch El (ft) 248 Shear (lb/sq ft) 0.22 0.61 0.17 Alpha 2.02 Stream Power (lb/ft s) 0.26 2.1 0.16 Frctn Loss (ft) 1.08 Cum Volume (acre-ft) 1.68 3.08 1.59 C & E Loss (ft) 0.01 Cum SA (acres) 1.91 1.69 2.28 Plan: Plan 01 River: Carter's Creek T Reach:CCT Riv Sta: 1275 Profile: PF 2 E.G. Elev (ft) 251 .62 Element Vel Head (ft) 0.13 Wt. n-Val. W.S. Elev (ft) 251.49 Reach Len. (ft) Grit W .S. (ft) Flow Area (sq ft) E.G. Slope (fUft) 0.003913 Area (sq ft) Q Total (cfs) 432 Flow (cfs) Top Width (ft) 186.1 Top Width (ft) Vel Total (fUs) 2.01 Avg. Vel. (ft/s) Max Chi Dpth (ft) 3.49 Hydr. Depth (ft) Conv. Total (cfs) 6906.3 Conv. (cfs) Length Wtd. (ft) 309 Wetted Per. (ft) Min Ch El (ft) 248 Shear (lb/sq ft) Alpha 2:02 Stream Power (lb/ft s) Frctn Loss (ft) 1.08 Cum Volume (acre-ft) C & E Loss (ft) 0.01 Cum SA (acres) Left OB 0.075 309 97.11 97.11 115.42 103.39 1.19 0.94 1845.1 103.41 0.23 0.27 1.72 1.92 Channel Right OB 0.05 0.075 309 309 81 .76 35.63 81 .76 35.63 281 .7 34.88 32 50.71 3.45 0.98 2.56 0.7 4503.5 557.7 32.41 50.73 0.62 0.17 2.12 0.17 3.12 1.62 1.7 2.3 EXHIBIT E-2 6/16/2006 HECRAS-Cross Section-Output EXHIBIT E-2 Plan: Plan 01 River: Carter's Creek T Reach:CCT Riv Sta: 300 Profile: PF 1 E.G. Elev (ft) 246.2 Element Left OB Channel Right OB Vel Head (ft) 0.04 Wt. n-Val. 0.05 W .S. Elev (ft) 246.15 Reach Len. (ft) 300 300 300 Crit W .S. (ft) 244.88 Flow Area (sq ft) 291 .5 E.G. Slope (ft/ft) 0.001637 Area (sq ft) 291 .5 Q Total (cfs) 482 Flow (cfs) 482 Top Width (ft) 180.23 Top Width (ft) 180.23 Vel Total (ft/s) 1.65 Avg. Vel. (ft/s) 1.65 Max Chi Dpth (ft) 3.2 Hydr. Depth (ft) 1.62 Conv. Total (cfs) 11913.5 Conv. (cfs) 11914 Length Wtd. (ft) 300 Wetted Per. (ft) 180.74 Min Ch El (ft) 242.95 Shear (lb/sq ft) 0.16 Alpha 1 Stream Power (lb/ft s) 0.27 Frctn Loss (ft) 1.23 Cum Volume (acre-ft) 0.07 1.18 0.43 C & E Loss (ft) 0.02 Cum SA (acres) 0.19 0.78 1.19 Plan: Plan 01 River: Carter's Creek T Reach:CCT Riv Sta: 300 Profile: PF 2 E.G. Elev (ft) 246.22 Element Vel Head (ft) 0.04 Wt. n-Val. W.S. Elev (ft) 246.18 Reach Len. (ft) Crit W.S. (ft) 244.89 Flow Area (sq ft) E.G . Slope (ft/ft) 0.001646 Area (sq ft) Q Total (cfs) 494 Flow (cfs) Top Width (ft) 181 .26 Top Width (ft) Vel Total (ft/s) 1.67 Avg. Vel. (ft/s) Max Chi Dpth (ft) 3.23 Hydr. Depth (ft) Conv. Total (cfs) 12176.5 Conv. (cfs) Length Wtd. (ft) 300 Wetted Per. (ft) Min Ch El (ft) 242.95 Shear (lb/sq ft) Alpha 1 Stream Power (lb/ft s) Frctn Loss (ft) 1.25 Cum Volume (acre-ft) C & E Loss (ft) 0.02 Cum SA (acres) Left OB 300 0.07 0.19 Channel Right OB 0.05 300 300 296.02 296.02 494 181 .26 1.67 1.63 12177 181 .78 0.17 0.28 1.19 0.44 0.78 1.19 EXHIBIT E-2 6/16/2006 HECRAS-Cross Section-Output April27,2006 Mr. Lance Sims, Assistant Director Planning and Development Services CITY OF COLLEGE STATION P.O. Box 9960 College Station, TX 77842 RE: Carters Crossing Subdivision Dear Mr. Sims: Please be advised that I approve of the proposed drainage plan for the Carter's Crossing 47.737 acre subdivision. The property outfalls into an un-named tributary of Carter's Creek near the south comer of my 20. 69 acre tract. I understand that the un-detained peak run-off from the proposed development will result in approximately a 0.08 foot (one inch) increase in the water surface elevation of the Base Flood as it enters my property. V/jltruly yours, ~ ;:: "-"-'-"-'LloO'"'< Patricia Guseman EXHIBIT F-1