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HomeMy WebLinkAboutDrainage Report March 18, 2015 stripes DRAINAGE REPORT FOR Stripes Convenience Store 13601 F.M. 2154 College Station, TX Brazos County 44, * * * • Developer: PAUL J.MOSS Stripes, LLC 116731 4525 Ayers St. s" Corpus Christi, TX 78415 Paul J. Moss, P.E. State of Texas No.: 116731 ARRIS(-)N FRENCH ASNOCI VS I I- 1) 1705 S.Walton Blvd,Suite 3 Phone: 479.273.7780 Bentonville,AR 72712 Fax: 479.273.9436 www.hfa-ae.coni 3So- 115 I -,30 Table of Contents DRAINAGE REPORT Stripes Convenience Store 13601 F.M. 2154 College Station, TX No. Description A. Site Location Summary B. Project Area C. Drainage Study Area D. Drainage Design Criteria E. Drainage System Design F. Conclusions Appendices A. Vicinity Map B. Soils Map C. Pre-Development Drainage Plan D. Post-Development Drainage Plan E. Drainage Calculations The detention area will be released through a combination grate inlet orifice structure located downstream of the detention pond.An allowable outfall release rate was determined for each design storm by rational method mitigation techniques. Due to storm system design limitations and elevation limitations the 2yr storm event dictated the outfall control orifice size (BCS Unified Stormwater Design Guidelines states outfall structures must be designed to comply with all storm events analyzed).It was determined that a 7.6-inch orifice would be sufficient to discharge the detention pond at a rate acceptable per the BCS Unified Stormwater Design Guidelines.Calculations are shown in the appendices. After stormwater passes through the outfall control structure it will be discharged into the roadside ditch flowing north along F.M.2154.The water will then follow the existing drainage path described in Section C of this document. . Stormwater Runoff Conditions 1 Basin Areal TC2 C l-2yr3 l-5yr3 I-10yr3 l-25yr3 l-50yr3 l-100yr3 A 1.50 19.32 0.43 4.52 _ 5.58 6.33 7.25 _ 8.23 8.58 81 0.22 10.00 0.91 6.33 7.69 8.63 9.86 11.15 11.64 82 0.35 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 B3 0.22 10.00 0.95 , 6.33 7.69 8.63 9.86 11.15 11.64 B4 0.03 10.00 0.40 6.33 i 7.69 8.63 9.86 11.15 11.64 B5 0.21 10.00 0.95 6.33 7.69 _ 8.63 9.86 11.15 11.64 B6 0.07 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 B7 0.11 10.00 • 0.40 6.33 7.69 8.63 9.86 11.15 11.64 88 0.03 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 B9 0.08 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 Pond 0.18 10.00 0.60 1 6.33 i 7.69 8.63 9.86 11.15 11.64 Table 1:Storm water Runoff Conditions Note 1-Measured in acres Note 2-Measured in minutes Note 3-Measured in inches per hour(injhr) Stormwater Runoff Rates Condition Pre-Developed Post-Developed Allowable Post-Developed w/o Detention Detention Release w/Detention Q-2yr 2.9cfs 7.9cfs 2.3cfs ; 2.3cfs Q-5yr - 3.6cfs 9.7cfs 2.8cfs 2.5cfs Q-10yr 4.1cfs 10.8cfs 3.2cfs 2.6cfs Q-25yr 1 4.6cfs I 12.3cfs 3.6cfs 2.8cfs Q-50yr 5.3cfs 14.Ocfs 4.1cfs 2.9cfs Q-10Oyr 5.5cfs 14.6cfs 4.3cfs 3.Ocfs Table 2:Stormwater Runoff Rates F.Conclusions By rational method pre/post analysis it was determined that detention will be required for the proposed Stripes Convenience Store at 13601 F.M.2154,College Station,TX.A stormwater management detention facility was designed to control stormwater runoff back to pre-existing conditions for all storm events analyzed (2yr, 5yr, 10yr, 25yr, SQyr, and 100yr)in accordance with BCS Unified Stormwater Design Guidelines. The drainage design in this report will control and minimize any adverse affects due to flooding or excessive rainfall. This includes damage to downstream structures, overcharging existing drainage infrastructure, and erosion along conveyance pathways. Gtr � _ . Q" ". 3 Sgt ` 'u bei C ' Q ,,,,,.„yam 3 )0-04 .45''0/4" (`1_ ,Cc,',--,,„4.'„%.,,),,,Z,..,.,v,.:,,,,-,,.,,..„.,*„.„- ).-. { ..''t';'g.,*,t,-,„;:,,,',fi•z4:n-:7.',:,4'- I tio- ,):,,.'. ?,,- ,;' G `^ � G, al 1 el a 1 RiduJog m rt , 2 St 4 , tea° N C .ilk ,, 0 4„, gF; .. ems . .,...00i#N11 11..,:t. ir B. SOILS MAP s Hydrologic Soil Group—Brazos County.Texas 758070 759910 258050 75999a 759030 /5,31.0.1 759110 '—- .....—-•. . 30•3994i 30°33'35 N 1 1 ... 1 1 1 1 i 1 1 , 1 , 1 , 1 1 1 1 i 1 1 „ 1 i , ,.-.,•,-:...,,,,I.C. 3,,S.3328"N 758870 758910 758950 798990 759030 759670 759110 C 8 Map Scarier 11,630 i printed on A o &(85 x 11")sheet, r, Meters i N0 20 40 80 120 Feet A0 50 100 200 300 Mao projecborc Web Mercator Corner coordinabes:WGSS4 Edge tcs:WM Zone 14N WGS84 USDA Natural Resources Web Soil Survey 6/2/2014 ;"' Conservation Service National Cooperative Soil Survey Page 1 of 4 a< Q 2 0 0 N N ° N fli � w 3 @ a�7 @ V m g7 N2.co co 3 N , ai ° Ocm � zmi m Z ° nv ' o a, N c 2 ?.,G 3 ' E c°ti� >m a r N ti - cY., as { `8 oa C > fi._ ° a. N 'o @ E d O)o N ° ,`oma O to t� a ° m = m a o Z E ai amv.� y `cea Fa) 0m v v, E wY0 4 M 7 Q Q t ¢`i 1 ' m N yS N ''' (II •O OQ N N•SS d Z R N N p �" 'i N O E O I O. gma. w-00 'j Q x r ''i ° m •• Q a E t0 E m N w 0c0 = p d N D .c ` C r1` m mc4i m E No acca,t - (n � d 0 ta og7 '.. o ar E3 m to 7-- ° , o o maga+ ° 03 , ° ar a v Qt13 r 3 7 T a o E T ct° u- N o a to.o0 o N a TL ?'g O N N E o 0 c N Q. a) E�+ Z -C oD 6 G N ° C' ..-,.0 m N 5•Q m D O 2 N �@ SO . m Ec o a 0 4) o m ° V) .C3 4`o --6 E dj aa`. ° O. E u.< 0 > 0-0-° m @_i� (°" mace m� oj> _ca m LOa+ ow V @ _ m E aom> ° Z so0 c R m ° N-� a m ° dE ° ° comm wa' - ° E @ `oa,�ie to c E-c w >.-: "yL (E asi, rn0 v m @ E 0 o j, . �G °a Oa. i. ° 2@ m y m d m o a ° o — o c-5_ 5 o c m .4 U) a t0 N -a < @ .0 N L C N -O C m , O R E g UJ a) o c 0 c o C'1 4' m -a c °Loau ' yE EQ@Qo as d a @,` •c-o `� Ema}m a' °oc Qoa� ° of ; @y � m �Q a� c 2E Nm 8cna II - a° wo Ern g oagm m mmmm mm &) o o_la. E ° o = "o-° mo � EmEE m F- I �} W E a H � E CO S d M n=0 4 v t-r cn GO cn `o d,- t- v._`o x ° H O 0 Um° O a @ Y it.. CO= m 1con 're ov n oo o y U m>, n 76 t6 m 3 m p US c U v m tot 'rt.; a v co `o m $2 m m o z d a o = o P 2 2 o w w a 0 19 N W Q m 0 a ° m o ° 4 i-", = o U d Z = in 3 Z m C 4 t` 3 F W J m m .n cQ ° W _ C G O N c C$1 N O C O a M 13 4 Q O A W G O w y Off. d a o a LI o a a p m d a m4 m 4 Z m n7 V U d Z m C 2 m m a U G 2 C Q •4 m m m 2 c t co .o U _ R 7.-W — DOOJEIL. 0111111 . 73 a co d c re Iii a :12 N O ZU �a Hydrologic Soil Group—Brazos County,Texas Hydrologic Soil Group Hydrologic Soil Group—Summary by Map Unit—Brazos County,Texas(TX041) Map unit symbol I Map unit name Rating I Acres in A01 Percent of A01 BwC Burlewash fine sandy D 3.5 44.9% loam,1 to 5 percent 1 slopes ' Sa ,Sandow loam,frequently C 0.1 1.3%. flooded ,----- TaA I Tabor fine sandy loam,0 D 0.9 12.0% to 2 percent slopes ZuB Zuich fine sandy loam 1 D 3.3 41.9% i to 3 percent slopes Totals for Area of Interest 7.9 100.0% 6/2/2014 Web Soil Survey uspA Natural Resources Page 3 of 4 4111110 Conservation Service National Cooperative Soil Survey Hydrologic Soil Group—Brazos County,Texas Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation,are thoroughly wet,and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups(A. B, C, and D)and three dual classes(A/D, B/D, and CID).The groups are defined as follows: Group A. Soils having a high infiltration rate(low runoff potential)when thoroughly wet.These consist mainly of deep,well drained to excessively drained sands or gravelly sands.These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep,moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture.These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet.These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture.These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate(high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group(A/D, B/D, or CID),the first letter is for drained areas and the second is for undrained areas.Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Natural Resources Web Soil Survey 81212014 Page 4 of 4 iirlr Conservation Service National Cooperative Soil Survey C. PRE-DEVELOPMENT DRAINAGE PLAN ( 1100141,14.114 MO., ! I Z. !I • ,.. -, ... • •••• , a it. 0— 4t a. 1 0.11§ I — . l ' i I it Il1 1 i it 14. rt, tf 'f .' I- 3 ...... , •, i.,..,i v. 45v,t i•-• 0,..t..!: , lid;t 1 '.,4,iiil fi 14 ig I/ itill. 1'1,1 !!,, l' ,i...,lisie tii) 1111 ) li Fil!1 Ilx 1 . ,1 .. I, , iv L. A ., . . , /41r „ : i ; ... - ‘ :, z " . / „ ' ,' ' -!'; '.• ' . , U ' • 4 / •••14-4-t--4---4-1:-::i .11 --, / I , i !! '' ' ' 0 € i , eNso , ' :lc ..,. , A- 1• '- .- t i 4,- , ! ii- ..... : . 11-i i,) :. 1 •,,c, : .,-. 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POST-DEVELOPMENT DRAINAGE PLAN xonn-91 +nv�nx roed Z <i 1 R p CO w ; N (, .� . ';.+ {F) sxu n'A�i3C s 3 S. o w in m Z 2 C.110 1 s...:.... ..SCS r-^ / can ia: 1 j # : �' X� a 3-13- ., ^-' 5. 1 ,;, „„....,...r.za C. *sod A- . I. : .4 I i g II .,,,_,.,,1,, . ., , : .,, _ 44 ..: i I A a F i i A S S 1Egp4. M s i s iii IF�iti Ste li �Rd 1Sflr t�3�d c 4 ¢ :A.sr a 11 II 3 1 ,3 ' • A5. \'F1i LII, k . (/. € •', •,.' fulte"--- I- '' i . ,':•,:i ., 1: N i!Olt. ,. ....','' % 1 i'' 7' ioI i. & ,*:& 4 1� , i - ‘;''Ipi.,, A --.P' \ 0 .•stogggIam ‘,1,-,, c3: q , . ,.. e, ._..............., , , . $, 10,1 ,,,,, .< .. tom,, f, . a c..i R R q1 , • 0 0 11 -41 z 1 a e N , rz 1 1l;,� a I ; ,1 • 4�i C' 0 j E�� , Pi i it, , •- 1_ '-11,, 1..\ .,, u ,!- . .Ld ' i 1 t ht.—. - '''. / : pi :I. ' ' ii\ki,, ;I • / N.`"..., .,,„,wr.,: i ,'.1,1, -.) .„-\\*.,-.1 4 3 4- Ft 3 d lkb `�0, . '''' '_:„,,,,,.:', ..-. 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DRAINAGE CALCULATIONS 76 Hydraflow Rainfall Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2013 by Autodesk,Inc.v10 Wednesday,081 1312014 Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period - , (Yrs) B D E (NIA) • 1 0.0000 0.0000 0.0000 ----- • i 2 65.0000 8.0000 0.8060 ----- 3 0.0000 0.0000 0.0000 -- 5 76.0000 8.5000 0.7850 ---- 10 80.0000 8.5000 0.7630 - • - • • 25 89.0000 8.5000 0.7540 -- 50 98.0000 8.5000 0.7450 ----- 100 96.0000 8.0000 0.7300 ----- File name:College Station,TX.IDF Intensity=B I(Tc+D)AE Return Intensity Values(in/hr) :Period40 45 50 55 60 (Yrs) 5 min 1 10 1 15 20 25 30 35 1 0,00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 8.22 6.33 5.19 4.43 3.88 3.46 3.14 2.87 2.65 2.46 2.30 2.17 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 9.85 7.69 6.38 5.48 j 4.83 4.33 3.93 3 61 3.34 3.12 2.92 2.75 1 11 10 10.98 8.63 7.19 6.21 5.49 4.94 4.50 4.14 3.84 , 3.59 3.37 3.18 25 12.51 9.86 8.23 7.12 6.30 5.67 5.18 4.77 4.43 4.14 3.89 3.68 50 14.10 11.15 9.33 8.08 7.16 1 6.46 5.90 5.44 ' 5.05 4.73 4.45 4.20 100 14.76 11.64 9.73 8.43 7.48 6.75 6.16 5.69 5.29 4.95 4.66 4.41 Tc=time in minutes.Values may exceed 60. Precip.file name:V:\Group Resources Civil\StormwateriHydraflow Data\PCP\College Station,TX.pcp I Rainfall Precipitation Table(in) • Storm 10_ r 25-yr 50-yr 100-yr Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 24-hour 0.00 4.50 0.00 6.20 7.40 8.40 0.00 11.00 SCS 6-Hr 0.00 0.00 0.00 , 0.00 0.00 0.00 0.00 0.00 Huff-1st 0.00 0.00 0.00 0.00 ' 0.00 0.00 0.00 i 0.00 Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 ' 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 . 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Pre and Post Developed Stormwater Runoff Rational Method Stripes Convenience Store,13601 F.M.2154,College Station,TX(Brazos County) Based upon: Bryan/College Station Unified Stormwater Design Guidelines BASIN A(Pre) Total Area 1.499 65,300 SF Impervious Area 0.073 acres 3,200 SF Pervious Area 1.426 acres 62,100 SF Runoff Coefficient (Table C-3) C 0.95 Roofs/Drives and Walks C 0.40 Unimproved-Average Weighted C I 0.43 I Time of Concentration Tc 0.322 Hours (Min.10 minutes) 19,32 Minutes Sheet Flow(Max.300 ft) Tsh 0.282 Hours Roughness Coefficient n 0.15 Sheet Flow Length(ft) L 300 2-yr,24hr rainfall depth(in.) P2 4.5 (Table C-6) Sheet Flow Slope(ft/ft) s 0.03 Shallow Concentrated Flow Tsc 0.040 Hours Flow Length(ft) D 6 Velocity(ft/sec) v 2.5 (Table C-4) Intensity(Table C-1) 10 yr 25 yr 50 yr 100 yr I(in/hr)=b/(tc+d)Ae I 4.52 5.58 6.33 I 7,25 I. 8.23 j 8.58 b 65 76 80 89 98 96 d 8.00 8.50 8.50 8.50 8.50 8.00 e 0.806 0.785 0,763 0.754 0.745 0.730 Runoff 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr Q ((cfs) I_ 2.9 I 3.6 4.0 4.6 5.3 5.5 POST DEVELOPMENT DRAINAGE BASINS Basin Area(ac) Area(scft) 1 C-Value Soil Type TC(min) 1 0.22 9585 0.91 D 10 2 0.35 15351 0.95 D 10 3 0.22 9734 0.95 D 10 4 0.03 1481 0.40 D 10 5 0.21 8960 0.95 D 10 6 0.07 3251 0.95 D 10 7 i 0.11 4860 0.40 D 10 8 0.03 1159 0.40 D 10 9 0.08 3543 0.40 CID 10 Pond 0.18 7963 0.65 0 10 INTENSITY(IN/HR) Basin 2 yr 5 yr 10 yr 25 yr I 50 yr 100 yr 1 . 6.33 7.69 8.63 9.86 11.15 11.64 2 6.33 7.69 8.63 9.86 11.15 11.64 3 6.33 7.69 8.63 9.86 11.15 11.64 4 6.33 7.69 8.63 9.86 11.15 11.64 5 6.33 7.69 8.63 9.86 11.15 11.64 6 6.33 7.69 8.63 9.86 11.15 11.64 7 6.33 7.69 8.63 9.86 11.15 11.64 8 6.33 7.69 8.63 9.86 11.15 11.64 9 6.33 7.69 8.63 9.86 11.15 11.64 Pond 6.33 7.69 8.63 9.86 11.15 11.64 RUNOFF(CFS) Basin 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 1 1.267 1.540 1.729 1.975 2.232 2.331 2 2.118- 2.575 2.891 3.302 3.732 3.897 3 1.343 1.633 1.833 2.093 2.367 2.471 4 0.086 0.105 0,117 0.134 0.152 0.158 5 • 1.210 1.472 1.652 1.886 2.132 2.227 6 0.449 0.545 0.612 0.699 0.790 0.825 7 0.282 0.343 0.385 0.440 0.497 0.519 8 0.067 0.082 0.092 0.105 0.119 0.124 9 0.206 0.250 0.281 0.321 0.363 0.379 Pond 0.891 1.083 1.215 1.388 1.569 1.638 Total I 7.919 9.629 10.808 12.343 13.953 14.568 Allowable Release Determination Pre-Development Flow minus Undetained Flaw equals Allowable Release Flow PRE-DEVELOPMENT FLOW(CFS) 2yr 5yr 10 yr ` 25 yr 50 yr I 100 yr 2.9 3,6 4.0 4.6 5.3 5.5 UNDETAINED AREA Basin Area(ac) C 4 0.03 0.40 7 0.11 0.40 8 0.03 0.40 9 0.08 0.40 Total 0.25 0.40 UNDETAINED FLOW(CFS) 2 yr 1 5yr I 10 yr 25 yr 50 yr j 100 yr 0.6 0.8 0.9 1.0 1.1 1.2 ALLOWABLE RELEASE(CFS) 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr I 2.3 2.8 3.2 3.6 4.1 4.3 Detention Pond Information DETAINED AREA 1 Basin Area(ac) C 1 0.220 0.91 2 0.352 0.95 3 0.223 0.95 4 0.034 0.95 5 0.206 0.93 6 _ 0.075 0.95 Pond 0.183 0.65 Total 1.259 0.90 Stage Storage Stage Storage Pond-4:1 Earthen Slopes with Concrete Swale CONTOUR INCR. PIPE TOTAL STAGE ELEVATION AREA STORAGE STORAGE STORAGE (ft) (ft) (sf) (cf) (cf) (cf) 0 329.25 0 0 0 1.00 330.25 854 285 285 2.00 331.25 1926 1354 487 1639 3.00 332.25 3304 2584 4223 4.00 333.25 4938 4094 8804 . � --_ ---' ---_--°- -----��- ---- - -~-r'�---�-� --`�---~�--� ---^-------- --� - �� Outfall Structure Calculations OUTFALL STRUCTURE - -- �- --- ---- --- - - -- - --- - - �Orifice Calculation Calculatio (2vR) Coefficient 0.8 Diameter 7.6 in 0.633333 ft Open Area A 031608I sq.ft. V | 32.2 | sA2 Head Head Flow (in) (ft) (cfs) | 27.64 2.3033 ORIFICE INVERT WATER ELEV. ELEV. 329.1 . 331.72 ! ! OUTFALL STRUCTURE Orifice Calculation(5 YR) Coefficient 0.6 Diameter d 7.6 in 0.633333 ft Open Area A | O 315032 | sq.ft. 32.2 ft/sA2 Head Head | | Flow H H � (In) (ft) (cfs) 34.6 2.8833 | � ORIFICE INVERT ' WATER ELEV. ELEV. 329.1 33230 OUTFALL STRUCTURE Orifice Calculation(10 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 I ft/s'2 Head Head Flow H H Q (in) (ft) (cfs) 37.24 I 3.1033 ORIFICE INVERT WATER ELEV. ELEV. 329.1 332.52 OUTFALL STRUCTURE Orifice Calculation(25 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow H H Q (in) (ft) (cfs) 40.48 3.3733 ORIFICE INVERT WATER ELEV. ELEV. 329.1 332.79 OUTFALL STRUCTURE Orifice Calculation(50 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 I ft/sA2 Head Head Flow H H Q (in) (ft) (cfs) 44.2 I 3.6833 I ORIFICE INVERT WATER ELEV. ELEV. 329.1 333.10 OUTFALL STRUCTURE Orifice Calculation(100 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/sA2 Head Head Flow H H Q (in) (ft) (cfs) 45.64 3.8033 ORIFICE INVERT WATER ELEV. ELEV. 329.1 333.22 PIPE SIZING CALCULATIONS BASIN B1(Curb Inlet) Q=1.4e/n4n352 n 0.012 Slope O.5 \ m PIPE Diameter i 12 in QFULL 2.74 cfs \ cfs 2.331 Diameter 11.30 in � Wetted Hydraulic Slope PIPE Area Perimeter Radius (ft/ft) Radius 0.5 ft 0.7854 [ 3141593 0.25 | 0.005i| BASIN 82(Grate Inlets) Q=1.49/nR~ 5 ' n 0.012 - Slope 0.5 % PIPE --- --- u�] db Diameter 15 in QFULL 4.96 ' � 3.897 cfs Diamrte, 13.70 in Wetted Hydraulic Slope PIPE Area Perimeter Radius (ft/Ii.) / Radius 0.625 ft 1,2272 3.926991 0.3125 O.OUs \ BASIN 85(Grate Inlet Includes 82) Q=2.49/nAn*351/2 0.012 oum Slope PIPE Diameter 18 in QFULL 8.07 cfs � 6.1231935 db Diameter 16.23 in Wetted Hydraulic PIPE Area Perimeter Radius Slope(ft/ft) Radius 0.75 ft 1J671459 _4712389 0.375 0.005 JUNCTION BOX 1(Includes BS,B2&B5) Q=1.49/n A 82/351/2 n 0.012 Slope 0.25% PIPE Diameter 24in QFULL 12.29 cfs Q 8.4537946cfs Diameter 20.86 in Wetted Hydraulic PIPE Area Perimeter Radius Slope(ftjft) !Radius 1ft 3.1415927 6.283185 0.5 0.0025 March 18, 2015 Revision 1 —4/30/15 Revision 2—6/1/15 stripes DRAINAGE REPORT FOR Stripes Convenience Store 13601 F.M. 2154 College Station, TX PF. Brazos County i—��iE. T �,,1� • Developer: , PAUL J.MOSSY • Stripes, LLC i .15% 116731 itti 4525 Ayers St. ta ., Corpus Christi, TX 78415 ;��PENs ••���� COY/5 Paul J. Moss, P.E. State of Texas No.: 116731 HFA \KC111I FCIS ENC.! \ IN I I.KI0KS 1705 S. Walton Blvd,Suite 3 Phone: 479.273.7780 Bentonville,AR 72712 Fax: 479.273.9436 www.hfa-ae.com Table of Contents DRAINAGE REPORT Stripes Convenience Store 13601 F.M. 2154 College Station, TX No. Description A. Site Location Summary B. Project Area C. Drainage Study Area D. Drainage Design Criteria E. Drainage System Design F. Conclusions Appendices A. Vicinity Map B. Soils Map C. FIRM Map D. Pre-Development Drainage Plan E. Post-Development Drainage Plan F. Area Drainage Map G. Drainage Calculations 13601 F.M. 2154 College Station, TX A. Site Location Summary The existing property is located at 13601 F.M. 2154 in College Station,TX(southeast corner of F.M.2154&SH 40 intersection).See Appendix A for a vicinity map. The adjacent properties to the site include State Highway 40 and a large residential subdivision to the north,grassed vacant areas to the east,a residential subdivision to the south,and F.M.2154(Wellborn Road)and vacant grassed areas to the west. The tract or parcel is situated in the Robert Stevenson Survey;abstract no.54, City of College Station, Brazos County, TX.Same being all that called 1.498 acre tract conveyed to Discount Fuels, LLC., by Mark Carrol Lenz and Mary Jane Lenz, by deeds recorded in volume 9853,page 11 and volume 9853, page 17 of the official public records of Brazos County,TX. The discharge point for stormwater runoff from with site is the roadside ditch along F.M.2154. B. Project Area Site: Address: 13601 FM 2154,College Station, Brazos County,TX 77845 Latitude: N30°33'33" Longitude: W96°18'01" Total Site Area: 1.50 Acres Total Disturbed Area: 2.60 Acres The existing site consists of a single residential building with grassed areas and moderate trees. The proposed site will be a small commercial development. Proposed improvements being considered consisting of the development of a prototypical ground up Stripes Convenience Store with fueling and 24 hour sales with beer/wine.Construction will consist primarily of demolition,drainage improvements,grading,paving,and commercial building construction associated item.Off-site roadway and roadside ditch work is proposed with this site. Project Owner: Stripes, LLC 4525 Ayers Road Corpus Christi,TX 78415 Topography: Lowest elevation on site: 328.94 Highest elevation on site: 335.76 Percent slope variation: Site generally slopes northwest to southeast at approximately 2.30%. C. Drainage Study Area Receiving Water: FM 2154 Drainage Area Distance to Receiving Water: approximately.50 miles Runoff Coefficients: .95(Impervious); .40(pervious) Soils: Site soils consist of Burlewash fine sandy loam,Tabor fine sandy loam,and Zulch fine sandy loam. The Hydrologic Soil Group rating for site soils is D. 5v Storm water runoff from the site travels into FM 2154 roadside ditch flowing northwest. Runoff flows for approximately one-half miles to culvert flowing under railroad tracks. Runoff is released into drainage area due west of culvert. Flood note: Site is in Zone X according to FIRM Panel 48041C0325E Above-Project Areas: Upstream area flow through the site was previously minimal to non-existent.The area north/northeast of the site flows to one of three outlet culverts along SH 40 and FM 2154. These culverts will continue to carry this area after development of Stripes Convenience Store.The rear of the adjacent neighborhood lots southeast of the site flows into an existing ditch along the southeast property line routing to FM 2154 drainage ditch.Areas upstream of the proposed development will continue to flow to the ditch along SH 40 and to the ditch along F.M.2154.The ditch along SH 40 will maintain the same high point with the added driveway dividing the flow directions to the east and west culvert. The existing ditch along the southeast property line will remain and be modified slightly due to development will continue to route upstream water from the southeast to F.M. 2154 drainage ditch. Upstream areas considered as "above- project"can be found in the appendices. Post-Development Drainage Plan: The post-development drainage improvements will consist of an on-site underground storm sewer system and outfall controlled detention area to service the proposed Stripes development.Above-project areas will not be routed through the on-site detention pond as their drainage patterns will not adversely affect upstream or downstream areas due to the proposed Stripes development. The above project areas will continue to be routed through existing storm runoff infrastructure as previously. The on-site detention area will be located at the south corner of the site, and have a storage capacity of approximately 8,800cu.ft. It will service approximately 1.25 acres of the 1.50 acre development (the remaining .25 acres will be directly released into existing storm runoff infrastructure and the runoff rate from the detention area mitigated accordingly). In order to preserve existing tree and plant life on-site, the detention pond will be released through an orifice restricted outfall pipe discharging in the roadside ditch along F.M. 2154 near the northwest corner of the property boundary. An emergency overflow weir will be constructed along the west side of the pond. The weir will along the pond to release excess runoff directly in the F.M 2154 roadside ditch,where it will flow to the culvert running under F.M 2154 D. Drainage Design Criteria The development of this site will increase the impervious area from 5%of the site to 79%of the site. The calculations for the runoff of the pre development and post development were obtained using the rational method. Per the rational method model, a 2-yr 24hr rainfall of 4.5-inches was used.The calculations are based on the criteria presented in the Unified Stormwater Design Guidelines for City of Bryan and City of College Station.The storm events analyzed were the 2yr, 5yr, 10yr, 25yr, 50yr, and 100yr. Due to the increase in impervious area, detention is anticipated to be required and implemented on-site. To discharge the detention pond an orifice restricted outfall structure combination grate inlet will be utilized in the design. The detention designed release rate was determined by a rational method pre- development and post-development analysis such that proposed conditions will not increase pre-existing flow rates to the existing drainage system. E. Drainage System Design 46. The proposed Stripes Convenience Store development will utilize an underground storm sewer system and outfall restricted detention pond to mitigate any increase in stormwater runoff to the existing infrastructure. Table 1: Stormwater Runoff Conditions details the basin conditions used for pre and post-development rational method Sae analysis.Table 2:Stormwater Runoff Rates details the flow rates generated by each of the pre-development conditions, post-development conditions without on-site detention, and post-development conditions with the use of on-site detention. 41110, The on-site detention pond will be an approximate 4-foot deep,4:1 side sloped earthen pond with a volume capacity of alok approximately 12,250 cu.ft. The pond will have a concrete lined drainage swale at the bottom sloping at 2%towards the outfall location to direct water within the pond. The pond is designed around two existing oak trees to be preserved. The pond will incorporate a 48'-0" wide emergency extreme event overflow weir on the west side near AM Wellborn Road roadside ditch. The weir will be used only in the event of a rainstorm exceeding the 100-yr event to prevent damage to the building,fueling canopy, and associated building structure items on-site.This includes the 100- ' " yr clogged outfall event. A plan view of the pond area and an elevation view of the overflow weir are shown in the appendices. The detention area will be released through a combination grate inlet orifice structure located downstream of the detention pond.An allowable outfall release rate was determined for each design storm by rational method mitigation ""`° techniques. Due to storm system design limitations and elevation limitations the 2yr storm event dictated the outfall control orifice size (BCS Unified Stormwater Design Guidelines states outfall structures must be designed to comply with all storm events analyzed). It was determined that a 7.6-inch orifice would be sufficient to discharge the detention pond at a rate acceptable per the BCS Unified Stormwater Design Guidelines.Calculations are shown in the appendices. After stormwater passes through the outfall control structure it will be discharged into the roadside ditch flowing north -. along F.M.2154.The water will then follow the existing drainage path described in Section C of this document. The site is not expected to have any ponding within the parking area. All inlet capture capacities exceed the runoff amount going to them.An analysis of each inlet capacity is shown in the appendices. Stormwater Runoff Conditions Basin Areal TC2 C I-2yr3 I-5yr3 I-10yr3 I-25yr3 I-50yr3 I-100yr3 A 1.50 19.32 0.43 4.52 5.58 6.33 7.25 8.23 8.58 B1 0.22 10.00 0.91 6.33 7.69 8.63 9.86 11.15 11.64 B2 0.35 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 „„.,, B3 0.22 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 B4 0.03 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 B5 0.21 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 B6 0.07 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 B7 0.11 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 B8 0.03 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 B9 0.08 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 Pond 0.18 10.00 0.60 6.33 7.69 8.63 9.86 11.15 11.64 Table 1:Stormwater Runoff Conditions ow Note 1-Measured in acres Note 2-Measured in minutes Note 3-Measured in inches per hour(in/hr) Stormwater Runoff Rates Condition Pre-Developed Post-Developed Allowable Post-Developed ,.. w/o Detention Detention Release w/Detention Q-2yr 2.9cfs 7.9cfs 2.3cfs 2.2cfs - Q-5yr 3.6cfs 9.7cfs 2.8cfs 2.4cfs Q-10yr 4.1cfs 10.8cfs 3.2cfs 2.5cfs Q-25yr 4.6cfs 12.3cfs 3.6cfs 2.7cfs Q-50yr 5.3cfs 14.0cfs 4.1cfs 2.8cfs Q-100yr 5.5cfs 14.6cfs 4.3cfs 2.9cfs Table 2:Stormwater Runoff Rates , F. Conclusions By rational method pre/post analysis it was determined that detention will be required for the proposed Stripes Convenience Store at 13601 F.M. 2154,College Station,TX.A stormwater management detention facility was designed arw to control stormwater runoff back to pre-existing conditions for all storm events analyzed (2yr, 5yr, 10yr, 25yr, 50yr, and 100yr) in accordance with BCS Unified Stormwater Design Guidelines. The drainage design in this report will control and minimize any adverse affects due to flooding or excessive rainfall. This includes damage to downstream structures, overcharging existing drainage infrastructure, and erosion along conveyance pathways. Slight discrepancies between hydrograph runoff values and calculated runoff values shown are due to rounding and software calculation time interval restrictions. A. VICINITY MAP 1 , " h s:be,..4' vt f t Ce si5r, C 9441'C 4) o�C. DeNIC544 <::� o�Ao E ...35 Aok cp c. kc."-' ve, .c., 1, 's• ...... In al Ofm, ���� Q ti. {g} ‘4 gf. .it 4...--4 -ro n r _ ri; VI IV ��� ti�1 a rn ' Q �Cti 4 o'i jitb �d y �tf. C+ ,� aye�lra ei 'cep pt`� °' c;° A fdd-`9‹, o is I G U, N�oJ dmf( ii. 1 A:14D '4::: p8 wo911aM N 010 1 V, w V hi i 0 4:0 -. t� ,p0 ...t ,..„ - i .-.,.,. ,.-, ,,,f.::.--.:-,,„;.i G\2 . „„2„ I., I0, iE. U y s.0 9 0 1 1 1 1 1 1 1 1 B. SOILS MAP 1 1 1 1 1 1 -. 4,... <...�.�.-..-. .. I Hydrologic Soil Group—Brazos County,Texas 5 IAq 758870 758910 758950 758990 759030 759070 759110 30°33'38"N . gam, • I 300 33'3e N ' 14 \1471. ° I . \ , ",a. meg.. '♦ M M \ , i Ps, M Oa ,17 O W A m w Aot(\, r we IP3 t, - Xi / m ,t s 4 _t;'' \ c V 11 I i , 4 • i m . r .. i [ 0 . 1 . i 1 ,.. $ tialop ,v i . a 1 IA 30°33'28"N ," ' I "1 30°33'28'N fill" 758870 758910 758950 758990 759030 759070 759110 I iiit9 Map Scale:1:1,630 if printed on A portrait(8.5"x 11")sheet Meters m N o 20 40 80 120 Pg 1. i 5Feet 0 50 100 200 300 a Map projection:Web Mercator Come-coordinates:WGS84 Edge tics:UTM Zone 14N WG584 USDA Natural Resources Web Soil Survey 6/2/2014 01.1-11 Conservation Service National Cooperative Soil Survey Page 1 of 4 I I vv a) .a) w O OI N O O = O N 00 T = N yI 0 O — 5. -c 7 CO p 2 d L (O cI 71 N = N (yp co y N U in I N'O to co V O c a) U_ ° a) V ai a] V = O 01 O L N H y 7 = fa = T O f° n Z 6 U 'O a) p N O ° cf0i � v0 co .0. E Uo N a» NE w 0 N 5rnE > — Y d U uoi N O = of I� > = a7._ N a N � E Z a7 ai 'a m CO.f° w O � uo w ( U a) = w h O co c W a O N 0 CO a1 ~ 3 H o m E o n w u) m 0 �- N Z m N - o L E co Q O r = N E f0 ° N W y C 7 7 Q X a) 'n° E U: a7 (° O Q p a� o t c o c Q vmw1° Udo � omNa°�i U z--..a L o Q °� v, 3 m ° @._ Y ° c p ° o y > t°ot c O .- TE =� E p� 0. o Erma LL y a � 'm � L 0 a�'i •a� Za° ai E o U c ui a a) E .0 CL 0E c>. a ° o 0 w •o � Q� o � � �0j 3 t- nww Q U CO W J N C U N a) Co E no n m as�. NQ O N `� m 0 o N O °' m E ME CO m d Z p E in°� a ni m w c v � m V V cL t >.:? co 3t cn c2 (D=° rnS f° m E `o5 >.= Z .O c N~ p ° a=i 0 7 Y ° co vco co oi U 13 > , •U o L o a a y U a) ;,, C U `E (n m E C O 7 c 7 O a)a) O 0n(° V • 0 0 ° . a7c o c' rno EL a> 7 a) u°) - o c N as ay 7 >. m rn yo r a, a„i n ami E m7oN mm 7 .0o 0 .°?�° `a) y > � � Em °? N mEmE ur H 43 5 W E ci.0 a E (on5.cp U 2 aVQ v .2 1) inr'n in `o 0 `r° F coi E o m x a) H r . T . m u) U _ co >,O N (07 > r m O N a o N j co c c.I 0 t m O ToIii . = H C U N .1 N O O L E2 'o a± Ra r -0 co N e CC O f0TO = 000 Z ! N C a E 0 2 J oQ ili Q m ti z 0 • U o m LLI F m • ILLJ a) o E c c 2 � o _ < o C) a) a) a co co a o co 0 to w d 0 0 O o J 0 0 0 p d 0 0 OI Q a 00000 Z OI < a (0 m 0 0 0 Z 0) < a m Co- - - C a C U No ❑ ❑ ■ ■ ❑ ❑ ❑ o1111110 ■ ■ ■ ■ UN I [ . ` •� fA N en 47 7 C O '33 Tom N 7 R O 2 V i 0 9I Hydrologic Soil Group—Brazos County,Texas I Hydrologic Soil Group II Hydrologic Soil Group—Summary by Map Unit—Brazos County,Texas(TX041) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI i BwC Burlewash fine sandy D 3.5 44 9% loam, 1 to 5 percent slopes Sa Sandow loam,frequently C 0.1 1.3% flooded r. TaA Tabor fine sandy loam,0 D 0.9 12.0% to 2 percent slopes iiiZuB Zulch fine sandy loam, 1 D 3.3 41.9% to 3 percent slopes Totals for Area of Interest 7.9 100.0% III it I Ii I I we WI IMO gi USDA Natural Resources Web Soil Survey 6/2/2014 Conservation Service National Cooperative Soil Survey Page 3 of 4 PM Hydrologic Soil Group—Brazos County,Texas I Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher USDA Natural Resources Web Soil Survey 6/2/2014 Conservation Service National Cooperative Soil Survey Page 4 of 4 1 1 1 1 1 1 1 1 C. FIRM MAP 1 1 1 1 1 1 ._ $I ii a �. a Iii a '" 'I t 'i l = III a kk iQn., id e ails i i= i e I I 1}I i =) ., I ! 41 = Ii .1 e I , it i"i jf Ip i i ii iii i 1 i 1${ t. i )f ii i ; I ifii�1i i i g �44 iii! W ii� =8ii1 i i Y it iii �� 9 1�1 iiij ( g {tl l ! 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PRE-DEVELOPMENT DRAINAGE PLAN e0000–et–m men-aR Alga < r ; :: (n ;jjjoj100 S 2 ��" y, ¢ U n Q Z a W u, wg .',''dQ. 3 a p � o a LL a Z g¢ ®dA� pp ¢ x as N cl s i3gar, i r stl R ! , R 3 R m ER i' 1 1 ii ;I `'%3d B 1 g ?a ° a' °zv. � . ��a s� c '3¢3e a v � I _;-� as li I I 1 °110 ' ' 1 h� 5 5 ry — 9K d4 i e v& 7.gt $` V s 2 a p a a a ag ecsgEg €s� F z o d c HU aBRRt - @@� �z e�� ppb- yy liar =Ia a F s9! s ii, 1 3 i g 5/ i 4/A1 / 1 !II II 00 Ks. tersQ 4i %f€ S9 I }Z a \ih, % u w N :r'' 1 n � ` \ I I • e d 9."-'-.''..m-'.'.\'''''"a ,o-.o...'.. 6":',\:,:=, . w=ee i-s'ioJ . E. POST-DEVELOPMENT DRAINAGE PLAN t 1 ■ I000o-gi-01 i nM MU d" Mc'ctccFccc g r 010 W N y MILLss•mntM MIT. a e^3 d a a 5 s 2 Vin r Q2 N � Y,,' Ma.M•KisIY k5 ! 1 Cr)Op Q z5 U e 2•,62101° LL a .1. JEi "�'" a ilE W! g a e e 2 i� gaa alw ..+.. x EEE 1. N sedifis k E B r o IYr M �I "U 80 4 II NM w y B LItiiII ki,i: - �'Q 5gg ! i1111 O ppp El 1 a' ti ?ei9®(i P.OQ �4- 0 ❑ ® • _EE O [ I 9 illi:, 41 I I 41 I" *41 I i o .°�= l�A b it • _ ;; 1 111 ei!Eil - ‘1;t4i,/,---7is i■110111fl3 � I�i !E 1 I! ! e,( j��112 1p!! 21:,,„,1,2 9 � i, .1 i i 11 III I 114;1;/\N i \1(1 - 1�0 eel 11 X11 II! 1:1 " ff.'A.' i'''.7 -.11 $1 a\ j C,1 er"i.' 1 1- 110 ii—°I '$� \ \:* ,I 01 o� • f �$ - i p I ,., ,.,, , ,i4 !E r z 1I D ; •I a I ar i I ep,\\ y I @ r 0 ,I II 11 bill \\ / �I 1 __, II I ee'E6E 1!!E `� -�> . !I ,,� =w wg. ,-",, ,. . II, , j \6, i / ,.. .fir _1 cPi oo 31 �i ib i.0 =ill v �� ll�l J� I. I �9 E kb c_____//q-t Li 4„ , 1 1 o, pN ..„ , 4T„, 3 , , „ . ,, ,_ ?1 bl �\ S --PoD00-St-0I\--"----"\---uw"•u-w0\wO\--ra\u r,i4 45•,ham i 000-SL-OAOL\.' 1 1 1 1 1 1 1 1 F. AREA DRAINAGE MAP 1 1 1 1 1 1 ca 1-4,....4.610411:. F i i w a �' '-''.11 �alti r k � t^' �4f J �'� �+ l� • * Iii: � :) 1 . lit = . • • 7... U rr 1 r do Q r'` ¢.i S , ' Z q.16'. 0 ii-- • �?�•4 Wear ,, - Xgtotc . I , . ' \ApiO4 1 Ai . � f W si I ! Z W � M D ; ' • W0 I v Q � Uaz * iI\ , i W ofr � i i. , ,$: -.. -.mg . 1 \ 0 \ .i• . "--,,.. ... ). 1I _ y W _`,.. T ,* • 7%,,_ ff W ,,, mo, .',... \\ i© t s \s, U �*, W - # • Y . f a.c.NN. • 1 1 G. DRAINAGE CALCULATIONS 1 1 ■ Pre and Post Developed Stormwater Runoff Rational Method ... Stripes Convenience Store, 13601 F.M.2154,College Station,TX(Brazos County) Based upon: Bryan/College Station Unified Stormwater Design Guidelines BASIN A(Pre) Total Area 1.50 65,300 SF Impervious Area 0.07 acres 3,200 SF Pervious Area 1.43 acres 62,100 SF Runoff Coefficient (Table C-3) C 0.95 Roofs/Drives and Walks C 0.40 Unimproved-Average Weighted C 0.43 1 r Time of Concentration Tc 0.322 Hours (Min. 10 minutes) 19.32 Minutes Sheet Flow(Max. 300 ft) Tsh 0.282 Hours Roughness Coefficient n 0.15 LSheet Flow Length(ft) L 300 2-yr,24hr rainfall depth (in.) P2 4.5 (Table C-6) Sheet Flow Slope(ft/ft) s 0.03 Shallow Concentrated Flow Tsc 0.040 Hours ° Flow Length(ft) D 6 Velocity(ft/sec) v 2.5 (Table C-4) I I Intensity(Table C-1) 10 yr 251 50 yr 100 yr I (in/hr)=b/(tc+d)Ae 4.52 5.58 6.33 7.25 8.23 8.58 b 65 76 80 89 98 96 r kii d 8.00 8.50 8.50 8.50 8.50 8.00 e 0.806 0.785 0.763 0.754 0.745 0.730 re alio Runoff5 yr 10 yr 25 yr 50 yr 100 yr Q(cfs) 2.9 3.6 4.0 4.6 5.3 5.5 1 p in iiist POST DEVELOPMENT DRAINAGE BASINS Basin Area(ac) Area(sqft) C-Value Soil Type TC(min) *ft 1 0.22 9585 0.91 D 10 2 0.35 15351 0.95 D 10 3 0.22 9734 0.95 D 10 4 0.03 1481 0.40 D 10 4 5 0.21 8960 0.95 D 10 6 0.07 3251 0.95 D 10 7 0.11 4860 0.40 D 10 8 0.03 1159 0.40 D 10 9 0.08 3543 0.40 C/D 10 Pond 0.18 7963 0.65 D 10 L INTENSITY(IN/HR) [ Basin 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 1 6.33 7.69 8.63 9.86 11.15 11.64 2 6.33 7.69 8.63 9.86 11.15 11.64 3 6.33 7.69 8.63 9.86 11.15 11.64 4 6.33 7.69 8.63 9.86 11.15 11.64 5 6.33 7.69 8.63 9.86 11.15 11.64 1 6 6.33 7.69 8.63 9.86 11.15 11.64 7 6.33 7.69 8.63 9.86 11.15 11.64 8 6.33 7.69 8.63 9.86 11.15 11.64 9 6.33 7.69 8.63 9.86 11.15 11.64 Pond 6.33 7.69 8.63 9.86 11.15 11.64 1 RUNOFF(CFS) Basin 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 1 1.27 1.54 1.73 1.98 2.23 2.33 2 2.12 2.58 2.89 3.30 3.73 3.90 3 1.34 1.63 1.83 2.09 2.37 2.47 4 0.09 0.11 0.12 0.13 0.15 0.16 5 1.21 1.47 1.65 1.89 2.13 2.23 6 0.45 0.55 0.61 0.70 0.79 0.83 7 0.28 0.34 0.39 0.44 0.50 0.52 8 0.07 0.08 0.09 0.101 0.12 0.12 9 0.21 0.25 0.28 0.32 0.36 0.38 Pond 0.89 1.08 1.22 1.39 1.57 1.64 E Total 7.92 9.63 10.81 12.34 13.95 14.57 IP Aimisormmim- Allowable Release Determination Pre-Development Flow minus Undetained Flow equals Allowable Release Flow PRE-DEVELOPMENT FLOW(CFS) 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 2.9 3.6 4.0 4.6 5.3 5.5 UNDETAINED AREA Basin Area(ac) C 4 0.03 0.40 7 0.11 0.40 8 0.03 0.40 9 0.08 0.40 Total 0.25 0.40 UNDETAINED FLOW(CFS) 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 0.6 0.8 0.9 1.0 1.2 1.2 ALLOWABLE RELEASE(CFS) 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 2.3 2.8 3.1 3.6 4.1 4.3 Detention Pond Information DETAINED AREA Basin Area(ac) C 1 0.220 0.91 2 0.352 0.95 3 0.223 0.95 4 0.034 0.95 5 0.206 0.93 6 0.075 0.95 Pond 0.183 0.65 Total 1.259 0.90 I Stage Storage Stage Storage Pond-4:1 Earthen Slopes with Concrete Swale CONTOUR INCR. PIPE TOTAL STAGE ELEVATION AREA STORAGE STORAGE STORAGE (ft) (ft) (sf) (cf) (cf) (cf) 0 329.10 0 0 0 1.00 330.10 854 528 243 528 2.00 331.10 1840 1968 652 2496 r s 3.00 332.10 3118 2451 242 4947 ir 4.00 333.10 4567 3820 1 8766 „ 4.15 333.25 4882 709 0 9475 r 4.65 333.75 6332 2796 0 12270 Storm event water surface elevations P 2yr—331.47 5yr—331.99 10yr—332.24 25yr—332.56 50yr—332.91 100yr—333.04 Emergency Overflow Weir Section Emergency Weir Sizing Calculation(100+YR) Weir Coefficient Head Width Gravity Flow Cd H(ft) b(ft) g(ft/s^2) QN(cfs) 0.6 0.20 48 32.2 13.78 Weir Crest 100yr Elevation Clogged El. 333.05 333.25 333.75 333.75 i ` / 333.75 333.75 / 333.25 100YR /CLOGGED 1NSE ca / 33o51ooYRWsE 48'-0" OVERFLOW WEIR I Outfall Structure Calculations OUTFALL STRUCTURE "" Orifice Calculation(2 YR) [ Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft I Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 I Head Head Flow H H Q (in) (ft) (cfs) I24.64 2.0533 IORIFICE INVERT WATER r ELEV. ELEV. 329.1 331.47 OUTFALL STRUCTURE Orifice Calculation(5 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft 1 Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 an Head Head Flow H H Q 4 0 (in) (ft) (cfs) 30.88 2.5733 ill ORIFICE INVERT WATER ELEV. ELEV. 329.1 331.99 I il Yr P I iho I OUTFALL STRUCTURE Orifice Calculation(10 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. Ig 32.2 ft/s^2 Head Head Flow I H H Q (in) (ft) (cfs) I33.88 2.8233 ORIFICE INVERT WATER ELEV. ELEV. 329.1 332.24 OUTFALL STRUCTURE Orifice Calculation(25 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow H H Q (in) (ft) (cfs) 37.72 3.1433 ORIFICE INVERT WATER I ELEV. ELEV. 329.1 332.56 4 p OUTFALL STRUCTURE Orifice Calculation(50 YR) I N Coefficient C 0.6 L Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. Ig 32.2 ft/s^2 Head Head Flow I H H Q (in) (ft) (cfs) 1 41.92 3.4933 2.835 I ORIFICE INVERT WATER ELEV. ELEV. I329.1 332.91 r OUTFALL STRUCTURE Orifice Calculation(100 YR) P. Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow I H H Q (in) (ft) (cfs) 43.48 3.6233 2,887' ORIFICE INVERT WATER 4 ELEV. ELEV. 329.1 333.04 I PIPE SIZING CALCULATIONS BASIN B1(Curb Inlet) Q=1.49/n A R2/351/2 n 0.012 Slope 0.5 % PIPE Diameter 12 in QFULL 2.74 cfs - Q 2.331 cfs Diameter 11.30 in Wetted Hydraulic Slope PIPE Area Perimeter Radius (ft/ft) Radius 0.5 ft 0.7854 3.141593 0.25 0.005 BASIN B2(Grate Inlets) Q=1.49/n A R2/351/2 ' n 0.012 Slope 0.5 % PIPE Diameter 15 in QFULL 4.96 cfs Q 3.897 cfs Diameter 13.70 in Wetted Hydraulic Slope PIPE Area Perimeter Radius (ft/ft) Radius 0.625 ft 1.2272 3.926991 0.3125 0.005 BASIN B5(Grate Inlet Includes 82) Q=1.49/n A R2135112 I I 0.012 Slope 0.5% i be PIPE Diameter 18 in QFULL 8.07 cfs q 6.1231935 cfs Diameter 16.23 in Wetted Hydraulic PIPE Area Perimeter Radius Slope(ft/ft) Radius 0.75ft 1.7671459 4.712389 0.375 0.005 JUNCTION BOX 1(Includes B1,B2&B5) Q=1.49/n A R213S1/2 n 0.012 Slope 0.25% PIPE Diameter 24 in QFULL 12.29cfs Q 8.4537946cfs Diameter 20.86 in Wetted Hydraulic PIPE Area Perimeter Radius Slope (ft/ft) 1 Radius 1ft 3.1415927 6.283185 0.5 0.0025 1 I 1 II I ' CAPACITY ANALYSIS Curb Inlet Grate Inlet Curb Cut Driveway Culvert ' Emergency Weir Capacity I I I I Inlet Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Apr 28 2015 <Name> Nth Curb Inlet Calculations Location = Sag Compute by: Q vs Depth Curb Length (ft) = 4.00 Max Depth (in) = 6 Throat Height (in) = 6.00 • Grate Area (sqft) = -0- Highlighted Grate Width (ft) = -0- Q Total (cfs) = 4.25 Grate Length (ft) = -0- Q Capt (cfs) = 4.25 Q Bypass (cfs) = -0- Gutter Depth at Inlet (in) = 6.00 Slope, Sw (ft/ft) = 0.020 Efficiency (%) = 100 ISlope, Sx (ft/ft) = 0.020 Gutter Spread (ft) = 25.02 Local Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) = -0- Gutter Slope (%) = -0- Bypass Depth (in) = -0- Gutter n-value = -0- No Nl Dimensions in feet e5 I1.5 23.52 • I 4- Inlet Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Apr 28 2015 [Tio <Name> Drop Grate Inlet Calculations ILocation = Sag Compute by: Q vs Depth Curb Length (ft) = -0- Max Depth (in) = 6 Throat Height (in) = -0- Grate Area (sqft) = 2.20 Highlighted L Grate Width (ft) = 2.50 Q Total (cfs) = 8.25 Grate Length (ft) = 2.50 Q Capt (cfs) = 8.25 r Q Bypass (cfs) = -0- L Gutter Depth at Inlet (in) = 5.84 Slope, Sw (ft/ft) = 0.015 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.015 Gutter Spread (ft) = 67.94 rb Local Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 3.00 Bypass Spread (ft) = -0- I r Gutter Slope (%) = -0- Bypass Depth (in) = -0- Gutter n-value = -0- I All dimensions infeef I I • 32.47 3.00 32 47 I Weir Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Apr 28 2015 <Name> Rectangular Weir Highlighted Crest = Sharp Depth (ft) = 0.50 Bottom Length (ft) = 4.00 Q (cfs) = 4.709 Total Depth (ft) = 0.50 Area (sqft) = 2.00 Velocity (ft/s) = 2.35 Calculations Top Width (ft) = 4.00 Weir Coeff. Cw = 3.33 tio Compute by: Q vs Depth No. Increments = 10 I P I `Depth (ft) <Name> Depth (ft) 1.00 1.00 r.L 0.50 —1 I — 0.50 or II iiii 0.00 0.00 r s 1 r �,n: -0.50 — -0.50 iiii 0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5 Weir W.S. Length (ft) IP Culvert Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Tuesday,Apr 28 2015 Circular Culvert Invert Elev Dn (ft) = 329.83 Calculations Pipe Length (ft) = 90.00 Qmin (cfs) = 0.00 Slope (%) = 0.89 Qmax (cfs) = 25.00 Invert Elev Up (ft) = 330.63 Tailwater Elev (ft) = (dc+D)/2 Rise (in) = 18.0 Shape = Circular Highlighted Span (in) = 18.0 Qtotal (cfs) = 12.00 No. Barrels = 1 Qpipe (cfs) = 12.00 n-Value = 0.012 Qovertop (cfs) = 0.00 Culvert Type = Circular Concrete Veloc Dn (ft/s) = 6.97 Culvert Entrance = Square edge w/headwall (C) Veloc Up (ft/s) = 6.79 Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 HGL Dn (ft) = 331.24 HGL Up (ft) = 332.21 Embankment Hw Elev (ft) = 333.46 Top Elevation (ft) = 333.63 Hw/D (ft) = 1.89 Top Width (ft) = 45.00 Flow Regime = Inlet Control Crest Width (ft) = 15.00 Eley(It) CName> Hw Depth(It) 33400 I 3.37 Inlet control 33300 2 37 ho 332 00 1 37 PIN 331.00 0.37 �..r ...4–. ..------w..— – —.063 330.00 329.00 _ -1.63 E 328.00 0 10 20 30 L 50 60 70 80 90 Embank tlq 110 120 130 Grctm CWvert HGL Reach(ft) 2 63 Weir Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Monday,Jun 1 2015 <N a me> Trapezoidal Weir Highlighted Crest = Sharp Depth (ft) = 0.65 Bottom Length (ft) = 48.00 Q (cfs) = 80.51 Total Depth (ft) = 0.65 Area (sqft) = 32.47 Side Slope (z:1) = 3.00 Velocity (ft/s) = 2.48 Top Width (ft) = 51 .90 Calculations Weir Coeff. Cw = 3.10 Compute by: Q vs Depth No. Increments = 10 Depth (ft) <Name> Depth (ft) 1.00 1.00 v 0.50 0.50 0.00 0.00 -0.50 — -0.50 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Weir W.S. Length (ft) 1 ' HYDROGRAPHS ' Pre-Development Post-Development Post-Development w/ Detention 1 I ■ 13 Hydraflow Rainfall Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 aiii Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period bop (Yrs) B D E (N/A) 1 0.0000 0.0000 0.0000 2 65.0000 8.0000 0.8060 3 0.0000 0.0000 0.0000 [ 5 76.0000 8.5000 0.7850 [ 10 80.0000 8.5000 0.7630 25 89.0000 8.5000 0.7540 50 98.0000 8.5000 0.7450 [ 100 96.0000 I 8.0000 0.7300 File name:College Station IDF.IDF Intensity= B/(Tc+ D)AE Return Intensity Values(in/hr) Period (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 I 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 8.22 6.33 5.19 4.43 3.88 3.46 3.14 2.87 2.65 2.46 2.30 2.17 I 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 9.85 7.69 6.38 5.48 4.83 4.33 3.93 3.61 3.34 3.12 2.92 2.75 10 10.98 8.63 7.19 6.21 5.49 4.94 4.50 4.14 3.84 3.59 3.37 3.18 25 12.51 9.86 8.23 7.12 6.30 5.67 5.18 4.77 4.43 4.14 3.89 3.68 -. 50 14.10 11.15 9.33 8.08 7.16 6.46 5.90 5.44 5.05 4.73 4.45 4.20 100 14.76 11.64 9.73 8.43 7.48 6.75 6.16 5.69 5.29 4.95 4.66 4.41 011 Tc=time in minutes.Values may exceed 60. ii. Precip.file name:I:\18\18-15-30003 Warehouse 8\Disciplines\Civil\Drainage\City of Bentonville.pcp Rainfall Precipitation Table(in) ill Storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ISCS 6-Hr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 I Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 I Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 . Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 2.943 cfs Storm frequency = 2 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 3,355 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 4.563 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development o (cfs) Hyd. No. 1 --2 Year 0 (cfs) 3.00 3.00 r 2.00 - 2.00 1.00 1.00 0.00 - 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Time (hrs) Hyd No. 1 3 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 3.635 cfs Storm frequency = 5 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 4,144 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 5.636 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development Q (cfs) Hyd. No. 1 --5 Year D (cfs) 4.00 4.00 3.00 3.00 L 2.00 2.00 r'" 1.00 1.00 0.00 - 0.00 i t 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Hyd No. 1 Time (hrs) 5 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 4.116 cfs Storm frequency = 10 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 4,692 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 6.381 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a 111 Pre Development 0 (cfs) Hyd. No. 1 -- 10 Year 0 (cfs) 5.00 5.00 4.00 4.00 I t. 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Time (hrs) Hyd No. 1 7 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 4.717 cfs 1. Storm frequency = 25 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 5,378 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 7.314 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a ill p Pre Development 0 (cfs) Hyd. No. 1 -- 25 Year 0 (cfs) 5.00 - 5.00 i Pm 4.00 4.00 I .. 3.00 3.00 I 2.00 2.00 I . i 1.00 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Time (hrs) Hyd No. 1 9 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 5.352 cfs Storm frequency = 50 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 6,101 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 8.297 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development 0 (cfs) Hyd. No. 1 -- 50 Year 0 (cfs) 6.00 6.00 5.00 5.00 4.00 4.00 3.00 - 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Time (hrs) Hyd No. 1 11 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 5.584 cfs Storm frequency = 100 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 6,366 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 8.657 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development 0 (cfs) Hyd. No. 1 -- 100 Year 0 (cfs) 6.00 6.00 5.00 - 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Time (hrs) Hyd No. 1 2 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 7.876 cfs Storm frequency = 2 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 4,726 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 6.327 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development 0 (cfs) Hyd. No. 2-- 2 Year 0 (cfs) 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Time (hrs) Hyd No. 2 4 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 9.578 cfs Storm frequency = 5 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 5,747 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 7.693 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development 0 (cfs) 0 (cfs) Hyd. No. 2--5 Year 10.00 10.00 8.008.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Time (hrs) Hyd No. 2 6 Hydrograph Report Hydraflow Hydrographs Extension for AutoCADO Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 10.75 cfs Storm frequency = 10 yrs Time to peak = 0.17 hrs 6. Time interval = 1 min Hyd. volume = 6,450 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 8.635 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc 0, Target Q =n/a Est. Req'd Storage =n/a hob P I Post Development 0 (cfs) Hyd. No. 2-- 10 Year 0 (cfs) 12.00 12.00 r 10.00 - 10.00 0 8.00 8.00 r I6.00 6.00 I4.00 4.00 2.00 2.00 0 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Time (hrs) Hyd No. 2 I 8 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 12.28 cfs Storm frequency = 25 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 7,367 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 9.861 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development Q (cfs) Hyd. No. 2-- 25 Year C� (cfs) 14.00 14.00 12.00 12.00 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Time (hrs) Hyd No. 2 10 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 13.88 cfs Storm frequency = 50 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 8,327 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 11.148 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development 0 (cfs) 0 (cfs) Hyd. No. 2 -- 50 Year 14.00 14.00 I 12.00 12.00 L 10.00 10.00 8.00 8.00 6.00 6.00 I 4.00 4.00 I 2.00 - 2.00 ii 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Time (hrs) Hyd No. 2 12 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 14.49 cfs Storm frequency = 100 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 8,694 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 11.639 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a r Post Development 0 (cfs) Hyd. No. 2-- 100 Year 0 (cfs) 15.00 15.00 12.00 12.00 9.00 9.00 I 6.00 6.00 3.00 3.00 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Time (hrs) Hyd No. 2 r■ r.� Post-Dev 2yr Hydrogra ph mho 2.0 +*� 1.5 Cr —4—Post-Dev 2yr 0 1.0 Hydrograph LL 0.5 : 0.0 0.0 20.0 40.0 60.0 80.0 Time(min) RIPOP Post-Dev 5yr Hydrograph 1100, 3.0 2.5 tom �.» Cf 1.5 FAIL —f—Post-Dev 5yr LL 1.0 Hydrograph 0.5 F1111111 0.0 0.0 20.0 40.0 60.0 80.0 100.0 Time(min) rr aim tam Post-Dev 10yr Hydrograph 3.0 2.5 N 2.0 1.5 Post-Dev 10yr 1.0 Hydrograph 0.5 r 0.0 0.0 20.0 40.0 60.0 80.0 100.0 Time (min) Post-Dev 25yr Hydrograph 3.0 2.0 r a 1.5 --Post-Dev 25yr I LL 1.0 — Hydrograph 0.5 — - - — — 1 ----------- 0.0 20.0 40.0 60.0 80.0 100.0 120.0 10.0 Time (min) Ii I iii Fil hi Post-Dev 50yr Hydrograph 1 3.0 2.5 N 2.0 [ ua 1.5 o —4—Post-Dev 50yr u. 1.0 Hydrograph 0.5 r 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 [ Time (min) Post-Dev 100yr Hydrogra ph I 3.0 2.5 "w" 7 2.0 I- u 1 L 1.5 - , II I a c —Post Dev 100yr LL 1.0 Hydrograph 0.5 0.0 . 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 1 Time (min) I I March 18, 2015 is St riPeS DRAINAGE REPORT FOR Stripes Convenience Store 13601 F.M. 2154 College Station, TX .0... , e OF rp„, ..e./ ... Brazos County if*/ 4'''' $4\* 4 .* *1 *: Developer: $ PAUL J.MOSS Stripes, LLC 4525 Ayers St. 116131 "hti4 4 Ir. 4140 Corpus Christi, TX 78415 % , ,.:to., r. .... - L./trio, Paul J. Moss, P.E. State of Texas No.: 116731 HFA HARRISON FRENCH S F ATI T D , , , 1705 S.Walton Blvd,Suite 3 Phone: 479.273.7780 Bentonville,AR 72712 Fax: 479.273.9436 IA ww.hfa-ae.eo in Table of Contents DRAINAGE REPORT Stripes Convenience Store 13601 F.M. 2154 College Station, TX No. Description A. Site Location Summary B. Project Area C. Drainage Study Area D. Drainage Design Criteria E. Drainage System Design F. Conclusions Appendices A. Vicinity Map B. Soils Map C. FIRM Map D. Pre-Development Drainage Plan E. Post-Development Drainage Plan F. Area Drainage Map G. Drainage Calculations 13601 F.M. 2154 College Station, TX A. Site Location Summary The existing property is located at 13601 F.M. 2154 in College Station,TX(southeast corner of F.M. 2154&SH 40 intersection).See Appendix A for a vicinity map. The adjacent properties to the site include State Highway 40 and a large residential subdivision to the north,grassed vacant areas to the east, a residential subdivision to the south, and F.M. 2154 (Wellborn Road)and vacant grassed areas to the west. The tract or parcel is situated in the Robert Stevenson Survey;abstract no. 54, City of College Station, Brazos County, TX. Same being all that called 1.498 acre tract conveyed to Discount Fuels, LLC., by Mark Carrol Lenz and Mary Jane Lenz, by deeds recorded in volume 9853, page 11 and volume 9853, page 17 of the official public records of Brazos County,TX. The discharge point for stormwater runoff from with site is the roadside ditch along F.M. 2154. B. Project Area Site: Address: 13601 FM 2154,College Station, Brazos County,TX 77845 Latitude: N30°33'33" Longitude: W96°18'01" Total Site Area: 1.50 Acres Total Disturbed Area: 2.60 Acres The existing site consists of a single residential building with grassed areas and moderate trees. The proposed site will be a small commercial development. Proposed improvements being considered consisting of the development of a prototypical ground up Stripes Convenience Store with fueling and 24 hour sales with beer/wine. Construction will consist primarily of demolition, drainage improvements,grading, paving, and commercial building construction associated item.Off-site roadway and roadside ditch work is proposed with this site. Project Owner: Stripes, LLC 4525 Ayers Road Corpus Christi,TX 78415 Topography: Lowest elevation on site: 328.94 Highest elevation on site: 335.76 Percent slope variation: Site generally slopes northwest to southeast at approximately 2.30%. C. Drainage Study Area Receiving Water: FM 2154 Drainage Area Distance to Receiving Water: approximately.50 miles Runoff Coefficients: .95 (Impervious); .40(pervious) Soils: Site soils consist of Burlewash fine sandy loam,Tabor fine sandy loam, and Zulch fine sandy loam. The Hydrologic Soil Group rating for site soils is D. Storm water runoff from the site travels into FM 2154 roadside ditch flowing northwest. Runoff flows for approximately one-half miles to culvert flowing under railroad tracks. Runoff is released into drainage area due west of culvert. Flood note: Site is in Zone X according to FIRM Panel 48041C0325E Above-Project Areas: Upstream area flow through the site was previously minimal to non-existent.The area north/northeast of the site flows to one of three outlet culverts along SH 40 and FM 2154. These culverts will continue to carry this area after development of Stripes Convenience Store. The rear of the adjacent neighborhood lots southeast of the site flows into an existing ditch along the southeast property line routing to FM 2154 drainage ditch. Areas upstream of the proposed development will continue to flow to the ditch along SH 40 and to the ditch along F.M. 2154.The ditch along SH 40 will maintain the same high point with the added driveway dividing the flow directions to the east and west culvert. The existing ditch along the southeast property line will remain and be modified slightly due to development will continue to route upstream water from the southeast to F.M. 2154 drainage ditch. Upstream areas considered as "above- project" can be found in the appendices. Post-Development Drainage Plan: The post-development drainage improvements will consist of an on-site underground storm sewer system and outfall controlled detention area to service the proposed Stripes development.Above-project areas will not be routed through the on-site detention pond as their drainage patterns will not adversely affect upstream or downstream areas due to the proposed Stripes development. The above project areas will continue to be routed through existing storm runoff infrastructure as previously. The on-site detention area will be located at the south corner of the site, and have a storage capacity of approximately 8,800cu.ft. It will service approximately 1.25 acres of the 1.50 acre development (the remaining .25 acres will be directly released into existing storm runoff infrastructure and the runoff rate from the detention area mitigated accordingly). In order to preserve existing tree and plant life on-site, the detention pond will be released through an orifice restricted outfall pipe discharging in the roadside ditch along F.M. 2154 near the northwest corner of the property boundary. An emergency overflow weir will be constructed along the west side of the pond. The weir will along the pond to release excess runoff directly in the F.M 2154 roadside ditch, where it will flow to the culvert running under F.M 2154 D. Drainage Design Criteria The development of this site will increase the impervious area from 5%of the site to 79% of the site. The calculations for the runoff of the pre development and post development were obtained using the rational method. Per the rational method model, a 2-yr 24hr rainfall of 4.5-inches was used. The calculations are based on the criteria presented in the Unified Stormwater Design Guidelines for City of Bryan and City of College Station.The storm events analyzed were the 2yr, 5yr, l0yr, 25yr, 50yr, and 100yr. Due to the increase in impervious area, detention is anticipated to be required and implemented on-site. To discharge the detention pond an orifice restricted outfall structure combination grate inlet will be utilized in the design. The detention designed release rate was determined by a rational method pre- development and post-development analysis such that proposed conditions will not increase pre-existing flow rates to the existing drainage system. E. Drainage System Design The proposed Stripes Convenience Store development will utilize an underground storm sewer system and outfall restricted detention pond to mitigate any increase in stormwater runoff to the existing infrastructure. Table 1: Stormwater Runoff Conditions details the basin conditions used for pre and post-development rational method analysis.Table 2:Stormwater Runoff Rates details the flow rates generated by each of the pre-development conditions, post-development conditions without on-site detention, and post-development conditions with the use of on-site detention. The on-site detention pond will be an approximate 4-foot deep, 3:1 side sloped earthen pond with a volume capacity of approximately 8,800cu.ft. The pond will have a concrete lined drainage swale at the bottom sloping at 2%towards the outfall location to direct water within the pond.The pond is designed around two existing oak trees to be preserved. A plan view of the pond area is shown in the appendices. The detention area will be released through a combination grate inlet orifice structure located downstream of the detention pond. An allowable outfall release rate was determined for each design storm by rational method mitigation techniques. Due to storm system design limitations and elevation limitations the 2yr storm event dictated the outfall control orifice size (BCS Unified Stormwater Design Guidelines states outfall structures must be designed to comply with all storm events analyzed). It was determined that a 7.6-inch orifice would be sufficient to discharge the detention pond at a rate acceptable per the BCS Unified Stormwater Design Guidelines. Calculations are shown in the appendices. After stormwater passes through the outfall control structure it will be discharged into the roadside ditch flowing north along F.M.2154.The water will then follow the existing drainage path described in Section C of this document. The site is not expected to have any ponding within the parking area. All inlet capture capacities exceed the runoff amount going to them.An analysis of each inlet capacity is shown in the appendices. Stormwater Runoff Conditions Basin Areal TC2 C I-2yr3 I-5yr3 I-10yr3 I-25yr3 I-50yr3 I-100yr3 A 1.50 19.32 0.43 4.52 5.58 6.33 7.25 8.23 8.58 B1 0.22 10.00 0.91 6.33 7.69 8.63 9.86 11.15 11.64 B2 0.35 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 B3 0.22 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 B4 0.03 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 B5 0.21 10.00 0.95 6.33 _ 7.69 8.63 9.86 11.15 11.64 B6 0.07 10.00 0.95 6.33 7.69 8.63 9.86 11.15 11.64 B7 0.11 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 B8 0.03 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 B9 0.08 10.00 0.40 6.33 7.69 8.63 9.86 11.15 11.64 Pond 0.18 10.00 0.60 6.33 7.69 8.63 9.86 11.15 11.64 Table 1:Storm water Runoff Conditions Note 1-Measured in acres Note 2-Measured in minutes Note 3-Measured in inches per hour(in/hr) Stormwater Runoff Rates Condition Pre-Developed Post-Developed Allowable Post-Developed w/o Detention Detention Release w/Detention Q-2yr 2.9cfs 7.9cfs 2.3cfs 2.2cfs Q-Syr 3.6cfs 9.7cfs 2.8cfs 2.4cfs Q-10yr 4.1cfs 10.8cfs 3.2cfs 2.5cfs Q-25yr 4.6cfs 12.3cfs 3.6cfs 2.7cfs Q-50yr 5.3cfs 14.Ocfs 4.1cfs 2.8cfs Q-100yr 5.5cfs 14.6cfs 4.3cfs 2.9cfs Table 2:Storm water Runoff Rates F. Conclusions By rational method pre/post analysis it was determined that detention will be required for the proposed Stripes Convenience Store at 13601 F.M. 2154, College Station,TX. A stormwater management detention facility was designed to control stormwater runoff back to pre-existing conditions for all storm events analyzed (2yr, 5yr, 10yr, 25yr, 50yr, and 100yr) in accordance with BCS Unified Stormwater Design Guidelines. The drainage design in this report will control and minimize any adverse affects due to flooding or excessive rainfall. This includes damage to downstream structures, overcharging existing drainage infrastructure, and erosion along conveyance pathways. Slight discrepancies between hydrograph runoff values and calculated runoff values shown are due to rounding and software calculation time interval restrictions. A. VICINITY MAP 4111111111111111111 1 , i 1 , ' , -. - - , « ,---- ._ . ' --,- ,,,.,. i .:2- .,,,, -,/, 1 ,-- --- 1 ,,,'' , ,..--- V -. , --'-' - .„ , - ,-, -, ,..,„ , , ›• 4,1;A... , , --:- - ••„,- '.-- - '1* ''' . -t,-. '--' -e-...,.. -'`•:7- : .,..., , •,, , .,,„--•:' , , _ 1 , ,... _E'.,...z ,.... ,-, ,. , „:' , - -' - ( 1 1 .;. .'-,-.. ,--, , . , ...,_ "( ::"..". , , ,_, , - ',.-. , ; ,„ ; 1 . -..- k _ -„,- -- / - ; v, 1 -( ;---, ''' n•, , 1 .... , 1 i •k--,'"' ,. i 1 - ,-- , , . -s' , , ..,,,. ,t .-....... „ .-, ..p., .... _ :°.... ,,,,,... 7- •,,-(„:-„i.,, ,., Illir ,. ..... .... B. SOILS MAP 3 Hydrologic Soil Group—Brazos County,Texas 3 ,tn so r. 758870 24:7e,,,,,.,,,,":‘,, , .,,s,;::::y,/?,,t?!1°',,,,'',‘,,,,,,,,,,,;:,,,, i 758910 758950 758990 759030 759070 759110 30°33 38 N .,. l 30°3338.N � 9 . many E� / ' 3 t, Q 1 9 m m� 1 if g ---, ®'fig r : >Cf '2 Rye J £ ,, t{fir �, ifreoy i I ,,,, .,:: ::' '''4t-:.,..:,-4,°e4gP.,,,,c,,,:siti':0#:,,o..0.!..,,,,.',111! ., 1 li / &iC •. 9 ice: f+l n p ib .! FO 30°33'28"N M �.. .,. .� - `; I- °rr1 30°33.20'N 758870 758910 758950 758990-.1,. 58990 759030 759070 759110 8 3 `a Fn Map Scale:1:1,630 if printed on A portrait(8.5'x 11")sheet h N Meters N 0 20 40 80 120 /V Feet 0 50 100 200 300 lap projection:Web Mercator Corner coordinates:WCS84 Edge tics:IJfM Zone 14N WGS84 Natural Resources Web Soil Survey_ 6/2/2014 ✓ v O c O m ° O >, C N N O - c O .LO.. Co O a7 - N a) O N 'o co c0 U O L co O) fV co° N to N aS O ` u) c0 N O La I a) - d O N U -O O @ c U U OS N 3 `p O a) `O c -p (0 a) .- ur N In a) -O c E 03 N C O) a U o 0 a O - -c Cl)u) ri - () 0 0- Co U u) a) o o ul N- N -p a) a N o as E Z a) a c0 a) O ` CaA) .L. co C0 a5 c Cl) 4 O O f6 °-'O f0 > c a N O U ME -3 LOLO. .N." N cU _ -° L a`) a) CDC7• o CO Cl N -O O ° .. L 0 < a) N O N Cl) u Z co -6 y N Z u) N U E u) C aNac E CIS CU Nw ma a .s Q axi _o oy s ,. a) �.• G Q is m a w asE Cl) o a m a t a) U) F- 0 a c w Cl) ac) -p N O U a)cs wp o N >; a) (° (6 O N Q -a O >, > LEoc a`) ` 3 � as � rc " a) c _ 0 o @ a> O O .L.. a3 N a) 0LL N o c 0 a)` m c m 3 o — 0 o E >' ca a) w a o co L O a) rig o .4 E o U c u) L a) E -0 nZ O a) O u) Q) �' 7 N U 'p c0 a) Cl) .O 01 °- ° a) > c as li E O >. 4 a) -6 m 0 f6 L O O. 0 a) -O O a) a) a D.L E Q m a) 3 o u 0 a3 u) - 0 L .3- J (n N a c U N m a) co L "" a) 5 to E c0 o a1 > 'p Z Q ° O a) .. a) O N O a) u, m E Cr) E t LO. > 2 L aim) aa)) CA rn� CD m m E o 0C c oa = -a CCA o > > a) LE .0m O � > o > O c F- O o c aS co .L... 3 -6 ' O - -O < N co O a L N U) ac) N ) o T E co a) E , o c o o > E 3 N o m - c E a) a) -,,Ti N N o 'p C ° O a) a6) '° p ` < a CO `- L `, O O• c a) -° L a) o a) U ca 7 T 0) 1. = a a) `C N � u) m m Sao a.� a`) o uai > - — cD m N oawco a) C ° L C - 25 a) a) o a) o 0 ,(7) -0.) 401-13 L a) 5 = 'o (6 m F- 5 W E a 0 QE coC.) 2 -=o Q U F- cn U to o 0 - 1- 0g18, x a) F- T T a) c a 7 o U U O >+=„) o > N CO (0 j a) CO CO Z O O a m 7 70 CO a O N L O m C c0 _c o m 3 a c0 w o L m 0 c mo 0 co o m a) o a) r Z a = U ci 0 z E c) o d' 0 2 J <N Q 0 co Z 0 0 0 0 "co t 0 s;, Q a W y �� Ft co c� � m U.1 J a) a) 0.. .0 12 ra, m < QO > > N N N O O E C c N u) c O O 0 a) o a N Q O T E yC @ c 2 d 0 0 �_ o J • 0 0 0 o d 0 0 e. < rn < Q C 00 0 0 0 Z Q) Q Q O7 O] 0 0 0 Z 0) Q Q O] C a) c c c a) CU co Q 0 O N O U 3 H w c a3 O Z U f �4 moi:' Hydrologic Soil Group—Brazos County,Texas Hydrologic Soil Group Hydrologic Soil Group—Summary by Map Unit—Brazos County,Texas(TX041) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI BwC Burlewash fine sandy D 3.5 44.9%, loam, 1 to 5 percent slopes Sa Sandow loam,frequently C 0.1 1.3% flooded TaA Tabor fine sandy loam,0 D 0.9 12.0% to 2 percent slopes ' ZuB Zulch fine sandy loam,1 D 3.3 41.9% to 3 percent slopes Totals for Area of Interest 7.9 100.0% USDA Natural Resources Web Soil Survey 6/2/2014 10111111 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group—Brazos County,Texas Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff. 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PRE-DEVELOPMENT DRAINAGE PLAN / ` ` ,e HFA /` / / / f� / / 1% e ,, Hill ( 1 ;/ I 1 / / /' / :l //) IvI, Iv � � it , %r/ I \ I I alit , 1// /' /' /' /` / ;' ;! 1 D SCALE �t / / / // `/ i /J/ 60 f' ' J//`� HARRISON FRE�Cf{ /1 1� f'; /.// I inch=90 rt. ^ , , �. „ I • �� %f/%/�� 1'05 S.Walton Blvd,Suite / / / f' /' / /`I/�//// Banonvillc..4kansae'2712 / / i /%�// 14'91'3.^90 // / ///// //" !' LEGEND f479 1 3.943b /' / / / // !/! // j ,, vu.hfa-az.cnm !'/ J' /O J / I ilfl'`//�:� BASIN / IMPERVIOUS AREA-0.0 SF(O.D ACRES) /NIJar ! J' `f/ PERVIOUS AREA-0,0 SF DRAINAGE BASIN SUMIMRy 111yyy L r Jlfi / f (0.0 ACRES) W b� I'" Ir/ / / // r / TOTAL AREA-0.0 SF(O.O ACRES) a!, �< �gy / 1 J r%"%/ J / SOILttPE•z• o e trt €i / ( �' ,,,/ 1/,�'J//// i /! PLOWS TO... Y b€ Pad b r i' ! i i ' of / / j" Elm S wgq]w �e!, /r ' 'I` / DRAINAGE BASIN BOUNDARY Pb 0 ,y,tl !1 / // ` '/ , "! f rI. r rn $ clktlE!!ll C 6�i ",l' i <-J DRAINAGE FLOW DIRECTION � � 3 / ! % 4/\/ i / j / 1 iQ i P / / / J /s/" J/ ' /` % `i/7 J stripes !' / "0 ' / j/ i i k Method f/ f/ f f,C v4 lirenienne54cle 13601 EM 2154, 0 in / / ! br \ n:&Yen/College Liiii, Coll Statiert TX(Brazos CGuts4 j / / f \ ...mAettee Design Ctidelinm j Q/ / 1 taw �Arm 0073c. 5;300 SF • co / , j f j / j 1.426 ares SF • . J / , ,//// ,,, \ 6 x / Y!f (Table t-3) ,1, . / ! ///N // C .495 Rppfs(Drives and Wa(ks L m N f ! weighted c tQ UmmProved As rNge !! ! 0.43 rCy7 ' / / /'///ff ',/" rr�gae TC o 3 Fjj / %! / f'<� ntrtesl 0.3z2 ars -U / //' /C!1 //i/ 19.32 Minutes _ �' tt(Mu.300([) Tsh ISSUE BLOCK / ! /,/i / i .oefficient 0.282 Nbart ,--® /14 i al / ,`1/; JAy// ,i'/ nath(tt} a D.1s Dere /j ; //: t,\ Sloaede/tI lin.l /08E 300 Rasa i /r t C` Slope Iftjft 2 AS (Tabte C-6 t r / \1•? J' •\ J s 0.03 ) t // f ' t j ncentrated F owco■ II Ill LEI j /,; /,/� 1 iFA n(hi. TI, 0�q0 .ours am oz/oa/t4 ;; �t l' i lx•I 6 • En all 1" %f!'ri1t I / /' i i ZS (Table C-4) t t t o_ ,/hr)_b/(tnd}^e 2 r S 10 a ! o \�./ f \ '\ 6.......6��® 100 -- h / e as, 8.50 a $� 9$ 96 T i �"----,_ 0.78.5 0.763.... $Sp $Op \ ? / .754 n ., 2r 0 5745 D(ds}�S r 10 r I 0,730 o \ •. Ilan W r CHEp® 50 r I ENT A e r a vi \ �.-�, `�. -s.;.___ _ _ 5.S /614 iii \\~/ � -- -----_,,4:,:y„ u ��T 0 � �_ ' d FOR go g o .c ONLY TE XAAS OA #F.85�5 PRE nN_ E. POST-DEVELOPMENT DRAINAGE PLAN F. AREA DRAINAGE MAP -;<..'`,.'',..:..„. '.*., , -04,,,..,''." :/144- -,=4,1'. a ' r ate. «r K *N , ,„ eL , 6:',','2. ,...::- -;,, ' ; '''"4, s 6 � � ®fir � F,. ` ' 4' y = lY ' 4m' h2 • "I'''' ' w 4 'ate '". -.W'-',t.:i:isi-7.'.,1'----°"'.;-14'''''''''''‘';';0,,, pt B z a 14 ,,,..., . ,. . .., ,., ., ..:,,, ,, , ............... ,..„ ..,, ,,, _,..,,,„,„....._ . . ____ , ._............ .•_-_ ,,,,,.... ,,,.. ' ' - - .-,, - ---------. „.„„ .........t..4.:.t„.,.... - - -- - ,......_,-,. ,,, ,,,,,,., .,,,,,. .-'-'----.. -,'`''''.--'''''' --- - ' ' ' ............"— ''''''''''''"":-.'"'-'-' - ..... ........-'—'71'' '' ,+= �, H, cam G. DRAINAGE CALCULATIONS Pre and Post Developed Stormwater Runoff Rational Method Stripes Convenience Store, 13601 F.M. 2154, College Station,TX(Brazos County) Based upon: Bryan/College Station Unified Stormwater Design Guidelines BASIN A(Pre) Total Area 1.50 65,300 SF Impervious Area 0.07 acres 3,200 SF Pervious Area 1.43 acres 62,100 SF Runoff Coefficient (Table C-3) C 0.95 Roofs/Drives and Walks C 0.40 Unimproved -Average Weighted C 0.43 Time of Concentration Tc 0.322 Hours (Min. 10 minutes) 19.32 Minutes Sheet Flow(Max. 300 ft) Tsh 0.282 Hours Roughness Coefficient n 0.15 Sheet Flow Length (ft) L 300 2-yr,24hr rainfall depth(in.) P2 4.5 (Table C-6) Sheet Flow Slope(ft/ft) s 0.03 Shallow Concentrated Flow Tsc 0.040 Hours Flow Length (ft) D 6 Velocity(ft/sec) v 2.5 (Table C-4) Intensity(Table C-1) 10 yr 25 yr 50 yr 100 yr I(in/hr)=b/(tc+d)^e 4.52 5.58 6.33 7.25 8.23 8.58 b 65 76 80 89 98 96 d 8.00 8.50 8.50 8.50 8.50 8.00 e 0.806 0.785 0.763 0.754 0.745 0.730 Runoff5 yr 10 yr 25 yr 50 yr 100 yr Q(cfs) 2.9 3.6 4.0 4.6 5.3 _ 5.5 J POST DEVELOPMENT DRAINAGE BASINS Basin Area (ac) Area (sqft) C-Value Soil Type TC(min) 1 0.22 9585 0.91 D 10 2 0.35 15351 0.95 D 10 3 0.22 9734 0.95 D 10 4 0.03 1481 0.40 D 10 5 0.21 8960 0.95 D 10 6 0.07 3251 0.95 D 10 7 0.11 4860 0.40 D 10 8 0.03 1159 0.40 D 10 9 0.08 3543 0.40 C/D 10 Pond 0.18 7963 0.65 D 10 INTENSITY(IN/HR) Basin 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 1 6.33 7.69 8.63 9.86 11.15 11.64 2 6.33 7.69 8.63 9.86 11.15 11.64 3 6.33 7.69 8.63 9.86 11.15 11.64 4 6.33 7.69 8.63 9.86 11.15 11.64 5 6.33 7.69 8.63 9.86 11.15 11.64 6 6.33 7.69 8.63 9.86 11.15 11.64 7 6.33 7.69 8.63 9.86 11.15 11.64 8 6.33 7.69 8.63 9.86 11.15 11.64 9 6.33 7.69 8.63 9.86 11.15 11.64 Pond 6.33 7.69 8.63 9.86 11.15 11.64 RUNOFF(CFS) Basin 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 1 1.27 1.54 1.73 1.98 2.23 2.33 2 2.12 2.58 2.89 3.30 3.73 3.90 3 1.34 1.63 1.83 2.09 2.37 2.47 4 0.09 0.11 0.12 0.13 0.15 0.16 5 1.21 1.47 1.65 1.89 2.13 2.23 6 0.45 0.55 0.61 0.70 0.79 0.83 7 0.28 0.34 0.39 0.44 0.50 0.52 8 0.07 0.08 0.09 0.101 0.12 0.12 9 0.21 0.25 0.28 0.32 0.36 0.38 Pond 0.89 1.08 1.22 1.39 1.57 1.64 Total 7.92 9.63 10.81 12.34 13.95 14.57 1 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 2.943 cfs Storm frequency = 2 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 3,355 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 4.563 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development 0 (cfs) Hyd. No. 1 --2 Year 0 (cfs) 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Hyd No. 1 Time (hrs) 2 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 7.876 cfs Storm frequency = 2 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 4,726 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 6.327 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development Q (cfs) Hyd. No. 2 --2 Year 0 (cfs) 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Hyd No. 2 Time (hrs) 3 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 3.635 cfs Storm frequency = 5 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 4,144 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 5.636 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development Q (cfs) Hyd. No. 1 -- 5 Year Q (cfs) 4.00I 4.00 3.00 3.00 2.00 - 2.00 1.00 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Hyd No. 1 Time (hrs) 4 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 9.578 cfs Storm frequency = 5 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 5,747 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 7.693 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development Q (cfs) Hyd. No. 2--5 Year Q (cfs) 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Time(hrs) Hyd No. 2 5 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 4.116 cfs Storm frequency = 10 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 4,692 cult Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 6.381 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs) 5.00 I 5.00 4.00 - 4.00 3.00 - 3.00 2.00 2.00 1.00 - 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Hyd No. 1 Time(hrs) 6 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 10.75 cfs Storm frequency = 10 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 6,450 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 8.635 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development Q (cfs) Hyd. No. 2 -- 10 Year Q (cfs) 12.00 12.00 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Time (hrs) Hyd No. 2 7 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 4.717 cfs Storm frequency = 25 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 5,378 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 7.314 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development Q (cfs) Hyd. No. 1 --25 Year Q (cfs) 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Hyd No. 1 Time (hrs) 8 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 12.28 cfs Storm frequency = 25 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 7,367 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 9.861 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development Q (cfs) Hyd. No. 2 --25 Year Q (cfs) 14.00 14.00 12.00 12.00 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Hyd No. 2 Time(hrs) . i 9 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 5.352 cfs Storm frequency = 50 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 6,101 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 8.297 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development Q (cfs) Hyd. No. 1 --50 Year Q (cfs) 6.00 6.00 5.00 5,00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Hyd No. 1 Time(hrs) 10 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 13.88 cfs Storm frequency = 50 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 8,327 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 11.148 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development Q (cfs) Hyd. No. 2 --50 Year 0 (cfs) 14.00 14.00 12.00 12.00 10.00 10.00 8.00 8.00 6.00 6.00 j,. 4.00 4.00 2.00 2.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Hyd No. 2 Time(hrs) 11 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 1 Pre Development Hydrograph type = Mod. Rational Peak discharge = 5.584 cfs Storm frequency = 100 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 6,366 cuft Drainage area = 1.500 ac Runoff coeff. = 0.43 Intensity = 8.657 in/hr Tc by User = 19.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Pre Development Q (cfs) Hyd. No. 1 -- 100 Year Q (cfs) 6.00 6.00 5.00 5.00 4.00 4.00 3.003.00 ,., 2.00 2.00 1.00 1.00 , \ 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 Hyd No. 1 Time(hrs) 12 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2015 by Autodesk, Inc.v10.4 Tuesday,04/28/2015 Hyd. No. 2 Post Development Hydrograph type = Mod. Rational Peak discharge = 14.49 cfs Storm frequency = 100 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 8,694 cuft Drainage area = 1.500 ac Runoff coeff. = 0.83 Intensity = 11 .639 in/hr Tc by User = 10.00 min IDF Curve = College Station IDF.IDF Storm duration = 1.0 x Tc Target Q =n/a Est. Req'd Storage =n/a Post Development o (cfs) Hyd. No. 2 -- 100 Year Q (cfs) 15.00 15.00 12.00 12.00 9.00 9.00 6.00 6.00 3.00 3.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Hyd No. 2 Time (hrs) 13 • Hydraflow Rainfall Report Hydraflow Hydrographs Extension for AutoCAD Civil 3D®2015 by Autodesk,Inc.v10.4 Tuesday,04/28/2015 Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period (Yrs) B D E (NIA) 1 0.0000 0.0000 0.0000 -- 2 65.0000 8.0000 0.8060 3 0.0000 0.0000 0.0000 -- 5 76.0000 8.5000 0.7850 ---- 10 80.0000 8.5000 0.7630 --- 25 89.0000 8.5000 0.7540 ---- 50 98.0000 8.5000 0.7450 --- 100 96.0000 8.0000 0.7300 ------ File name:College Station IDF.IDF Intensity= B/(Tc+ D)^E Return Intensity Values(in/hr) Period (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 8.22 6.33 5.19 4.43 3.88 3.46 3.14 2.87 2.65 2.46 2.30 2.17 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 9.85 7.69 6.38 5.48 4.83 4.33 3.93 3.61 3.34 3.12 2.92 2.75 10 10.98 8.63 7.19 6.21 5.49 4.94 4.50 4.14 3.84 3.59 3.37 3.18 25 12.51 9.86 8.23 7.12 6.30 5.67 5.18 4.77 4.43 4.14 3.89 3.68 50 14.10 11.15 9.33 8.08 7.16 6.46 5.90 5.44 5.05 4.73 4.45 4.20 100 14.76 11.64 9.73 8.43 7.48 6.75 6.16 5.69 5.29 4.95 4.66 4.41 Tc=time in minutes.Values may exceed 60. Precip.file name:I:\18\18-15-30003 Warehouse 8\Disciplines\Civil\Drainage\City of Bentonville.pcp Rainfall Precipitation Table(in) Storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SCS 6-Hr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Allowable Release Determination Pre-Development Flow minus Undetained Flow equals Allowable Release Flow PRE-DEVELOPMENT FLOW(CFS) 2yr 5yr 10 yr 25 yr 50 yr 100 yr 2.9 3.6 4.0 4.6 5.3 5.5 UNDETAINED AREA Basin Area (ac) C 4 0.03 0.40 7 0.11 0.40 8 0.03 0.40 9 0.08 0.40 Total 0.25 0.40 UNDETAINED FLOW(CFS) 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 0.6 0.8 0.9 1.0 1.2 1.2 ALLOWABLE RELEASE(CFS) 2 yr 5 yr 10 yr 25 yr 50 yr 100 yr 2.3 2.8 3.1 3.6 4.1 4.3 Detention Pond Information DETAINED AREA Basin Area(ac) C 1 0.220 0.91 2 0.352 0.95 3 0.223 0.95 4 0.034 0.95 5 0.206 0.93 6 0.075 0.95 Pond 0.183 0.65 Total 1.259 0.90 Stage Storage Stage Storage Pond-4:1 Earthen Slopes with Concrete Swale CONTOUR INCR. PIPE TOTAL STAGE ELEVATION AREA STORAGE STORAGE STORAGE (ft) (ft) (sf) (cf) (cf) (cf) 0 329.10 0 0 0 1.00 330.10 854 528 243 528 2.00 331.10 1926 2006 652 2534 3.00 332.10 3304 2584 242 5118 4.00 333.10 4938 4094 1 9212 4.15 333.25 6572 860 0 10072 Storm event water surface elevations 2yr—331.44 5yr—331.96 10yr—332.19 25yr—332.49 50yr—332.82 100yr—332.96 Emergency Overflow Weir Section 333.35 333.23 35 `� X33. 5 333. 33;x.DO , , Lo / "in 12/ 4, , i (...„ , „, `J 8 ,,, , t _., _ I 3g,_o„ .t r"i OVERFLOW WEIR L i Weir Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Tuesday,Apr 28 2015 <Name> Trapezoidal Weir Highlighted Crest = Sharp Depth (ft) = 0.25 Bottom Length (ft) = 39.00 Q (cfs) = 15.35 Total Depth (ft) = 0.25 Area (sqft) = 9.94 Side Slope (z:1) = 3.00 Velocity (ft/s) = 1 .54 Top Width (ft) = 40.50 Calculations Weir Coeff. Cw = 3.10 Compute by: Q vs Depth No. Increments = 5 Depth (ft) <Name> Depth (ft) 1.00 — - 1.00 0.50 0.50 _____ \ 0.00 - 0.00 -0.50 — - L— -0.50 0 5 10 15 20 25 30 35 40 45 50 55 Weir W.S. Length (ft) Outfall Structure Calculations OUTFALL STRUCTURE Orifice Calculation(2 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow H H Q (in) (ft) (cfs) 24.28 2.0233 ' ORIFICE INVERT WATER ELEV. ELEV. 329.1 331.44 OUTFALL STRUCTURE Orifice Calculation(5 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow H H Q (in) (ft) (cfs) 30.52 2.5433 ORIFICE INVERT WATER ELEV. ELEV. 329.1 331.96 . I OUTFALL STRUCTURE Orifice Calculation(10 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow H H Q (in) (ft) (cfs) 33.4 2.7833 ORIFICE INVERT WATER ELEV. ELEV. 329.1 332.20 OUTFALL STRUCTURE Orifice Calculation(25 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow H H Q (in) (ft) (cfs) 37 3.0833 Z h ORIFICE INVERT WATER ELEV. ELEV. 329.1 332.50 OUTFALL STRUCTURE Orifice Calculation(50 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow H H Q (in) (ft) (cfs) 40.96 3.4133 ORIFICE INVERT WATER ELEV. ELEV. 329.1 332.83 OUTFALL STRUCTURE Orifice Calculation(100 YR) Coefficient C 0.6 Diameter d 7.6 in 0.633333 ft Open Area A 0.315032 sq.ft. g 32.2 ft/s^2 Head Head Flow H H Q (in) (ft) (cfs) 42.52 3.5433 A111 $-' ORIFICE INVERT WATER ELEV. ELEV. 329.1 332.96 . . -` a r [— | 17-17-1-1 ! ; / ) / ( L —J ' 11=1111 MEi . 111E111M NNE 1111111111111' _MEM 11, | | ---- i -manta II ! " ' | | �— . ! / ' | | I ( / | ` ^_--- | | -------------' --------- -- } | CAPACITY ANALYSIS Curb Inlet Grate Inlet Curb Cut Driveway Culvert Inlet Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Apr 28 2015 <Name> Curb Inlet Calculations Location = Sag Compute by: 0 vs Depth Curb Length (ft) = 4.00 Max Depth (in) = 6 Throat Height (in) = 6.00 Grate Area (sqft) = -0- Highlighted Grate Width (ft) = -0- Q Total (cfs) = 4.25 Grate Length (ft) = -0- Q Capt (cfs) = 4.25 Q Bypass (cfs) = -0- Gutter Depth at Inlet (in) = 6.00 Slope, Sw (ft/ft) = 0.020 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.020 Gutter Spread (ft) = 25.02 Local Depr (in) _ -0- Gutter Vel (ft/s) _ -0- Gutter Width (ft) = 1.50 Bypass Spread (ft) = -0- Gutter Slope (%) = -0- Bypass Depth (in) = -0- Gutter n-value = -0- All dimensions In feet ,,,,--' /I/ / / Inlet Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Apr 28 2015 <Name> Drop Grate Inlet Calculations Location = Sag Compute by: Q vs Depth Curb Length (ft) = -0- Max Depth (in) = 6 Throat Height (in) = -0- Grate Area (sgft) = 2.20 Highlighted Grate Width (ft) = 2.50 Q Total (cfs) = 8.25 Grate Length (ft) = 2.50 Q Capt (cfs) = 8.25 Q Bypass (cfs) = -0- Gutter Depth at Inlet (in) = 5.84 Slope, Sw (ft/ft) = 0.015 Efficiency (%) = 100 Slope, Sx (ft/ft) = 0.015 Gutter Spread (ft) = 67.94 Local Depr (in) = -0- Gutter Vel (ft/s) = -0- Gutter Width (ft) = 3.00 Bypass Spread (ft) = -0- Gutter Slope (%) _ -0- Bypass Depth (in) = -0- Gutter n-value = -0- 1 Weir Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Tuesday,Apr 28 2015 <Name> Rectangular Weir Highlighted Crest = Sharp Depth (ft) = 0.50 Bottom Length (ft) = 4.00 Q (cfs) = 4.709 Total Depth (ft) = 0.50 Area (sqft) = 2.00 Velocity (ft/s) = 2.35 Calculations Top Width (ft) = 4.00 Weir Coeff. Cw = 3.33 Compute by: Q vs Depth No. Increments = 10 Depth (ft) <Name> Depth (ft) 1.00 1.00 0 0.50 — 0.50 4 0.00 — 0.00 -0.50 - -0.50 0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5 Weir W.S. Length (ft) Culvert Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Tuesday,Apr 28 2015 Circular Culvert Invert Elev Dn (ft) = 329.83 Calculations Pipe Length (ft) = 90.00 Qmin (cfs) = 0.00 Slope (%) = 0.89 Qmax (cfs) = 25.00 Invert Elev Up (ft) = 330.63 Tailwater Elev (ft) = (dc+D)/2 Rise (in) = 18.0 Shape = Circular Highlighted Span (in) = 18.0 Qtotal (cfs) = 12.00 No. Barrels = 1 Qpipe (cfs) = 12.00 n-Value = 0.012 Qovertop (cfs) = 0.00 Culvert Type = Circular Concrete Veloc Dn (ft/s) = 6.97 Culvert Entrance = Square edge w/headwall (C) Veloc Up (ft/s) = 6.79 Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 HGL Dn (ft) = 331.24 HGL Up (ft) = 332.21 Embankment Hw Elev (ft) = 333.46 Top Elevation (ft) = 333.63 Hw/D (ft) = 1.89 Top Width (ft) = 45.00 Flow Regime = Inlet Control Crest Width (ft) = 15.00 Bev On <Name. 1M DNA OD 334.0: ......... 3.37 333.00 r '(-464. 1 � _...... 2.37 332 a: 127 331 OE ,a n .m 0.37 __--- 330.00 -_' .._ _. .. .. ... .. -0.83 329.00 -- -1.63 328.00 -2.63 0 10 20 30 82 50 60 70 90 90 100 110 120 130 Grculn! u',vert HGL Embank Reach NO PIPE SIZING CALCULATIONS BASIN B1(Curb Inlet) Q=1.49/n A R2/351/2 n 0.012 Slope 0.5 % PIPE Diameter 12 in QFULL 2.74 cfs Q 2.331 cfs Diameter 11.30 in Wetted Hydraulic Slope PIPE Area Perimeter Radius (ft/ft) Radius 0.5 ft 0.7854 3.141593 0.25 0.005 I BASIN B2(Grate Inlets) Q=1.49/n A R2/3S1/2 n 0.012 Slope 0.5 % PIPE Diameter 15 in QFULL 4.96 cfs Q 3.897 cfs Diameter 13.70 in Wetted Hydraulic Slope PIPE Area Perimeter Radius (ft/ft) Radius 0.625 ft 1.2272 3.926991 0.3125 0.005 BASIN B5(Grate Inlet Includes B2) Q=1.49/n A R2/3S1/2 n 0.012 Slope 0.5% PIPE Diameter 18 in QFULL 8.07 cfs Q 6.1231935cfs Diameter 16.23 in Wetted Hydraulic PIPE Area Perimeter Radius Slope(ft/ft) Radius 0.75 ft 1.7671459 4.712389 0.375 0.005 JUNCTION BOX 1(Includes B1,B2&B5) Q=1.49/n A R2/351/2 n 0.012 Slope 0.25% PIPE Diameter 24 in QFULL 12.29 cfs Q 8.4537946 cfs Diameter 20.86 in Wetted Hydraulic PIPE Area Perimeter Radius Slope(ft/ft) Radius I 1ft 3.1415927 6.283185 0.5 0.0025