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HomeMy WebLinkAbout19 DP Eagle Ave Church 00-500049 1815 Eagle AveDRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION July 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 REVIEWED FOR l co~~PI ILH\ICE JUL 1 7 2000 COLLEGE STATION ENGINEERING ~ DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION July 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 CERTIFICATION I hereby certify that this report and accompanying drainage plan for the drainage design of Proposed Eagle A venue Church was prepared by me in accordance with the provisions of the City of College Station Drainage Po~, ~d _Design Standards for the owners thereof ...:i!.~-..c~~ ...e • . ... . ' A...."· "°'"-'1-............ 7 \jl fu ~ A"t~~ r-.•• • "• ": ~~ (~~~~/ 1~ ··~;~~)~· . // ~ .~.~.Cl .,.l!!,._,.L1'~.~·~·~···t:• / . R. G. ROSE~T'SON ~ ------~-~-~------f.l ...... ot•ttmu••·~-..·~·~ Registered Professional Engineer ~~·\-9: 5(?~75 ~/BJ' State of Texas No. 56375 ~··~Gts ""~~·"...~ k •• ' •• _,,.,"""°" ~O ••••r·••• G~..c;r' "Siar.A\.. ~, ~'~--- Introduction The proposed project is located on Eagle Avenue immediately west of State Highway 6 in the Springbrook Subdivision . The project consists of a new building and site improvements for a 2.099 acre tract . The site was originally part of a 5.751 acre tract which currently is occupied by Stylecraft Builders Inc. The lot for this project was replatted and separated from the original tract . Figure I shows the original drainage map for the Stylecraft project, taken from the drainage report prepared by McClure Engineering Inc . No portion of the project lies within the current boundaries of the regulatory I 00-year Floodplain for the City of College Station as shown on Brazos County FIRM #48041C0205 C. The project lies within the Lick Creek drainage basin . Existing Drainage Patterns The tract and relevant adjacent land areas that contribute runoff to it are undeveloped at this time . Existing land cover consists of natural grasslands. The site receives a substantial amount of off-site flows from areas to the north. The on-site and off-site stormwater flows are discharged to the east into a drainage channel in the adjacent drainage easement on the east side of the property. Proposed Drainage Patterns The proposed drainage patterns and improvements are depicted in Figure 2 . Detailed calculations for the improvements are contained in Append ices A -B. The plans for this project depict the detailed construction necessary to accomplish the proposed drainage improvements and are shown in Exhibit 1. The north area identified as IB will continue to discharge into the channel in the drainage easement on the east side of the property. No detention is needed for this site on the north area, as no new construction on this site will occur. The offsite areas to the north of this tract are assumed to contribute no additional runoff to this site when they are developed . The south area identified as IA represents the developed portion of the tract. Detention is provided for this portion of the site utilizing a portion of the proposed parking area on the southeast comer of the site. The curb will be built higher at the outlet end of the detention area and have a 6" width curb opening discharging into a 2 foot width concrete outlet weir. The detention basin will collect all waters from the developed area of this site and will discharge directly into the existing channel and drainage easement. The detention area is designed to limit the discharge for the 2-year to 100-year storms from the proposed project to less than the discharge that existed prior to construction. Emergency overflow of the detention area will occur over the curb into the channel. The detention basin will pond water to a maximum elevation of 279 .25 feet during the 100-year storm . A combined summary of pre-and post-development peak discharges for the project is provided in Table 1. 2-year 5-year 10-year 25-year 50-year 100-year storm storm storm storm storm storm Existing 1.56 1.89 2 .12 2.43 2 .74 2 .86 Develop 3 .70 4 .50 5.10 5.80 6 .60 6 .90 Outflow 1.84 1.96 1.98 2 .18 2.28 2 .31 Table 1. Peak Project Disch arges (cfs) Conclusions Although the calculations provided are numerically correct in the application of the principles of hydraulics and hydrology, the actual numbers are below the limits of what is considered the accuracy of the underlying methodology. Calculating discharges to the . 01 cfs, .1 cfs, or even 1 cfs , is false accuracy when using any hydrologic method . This site originally discharged about 2-3 cfs over the range of design storms considered. If no detention is provided it will only discharge 4 - 7 cfs from the same storms when ultimately developed . The detention provided will reduce that discharge to 2 -3 cfs . Within the accuracy of existing hydrologi c methods, these numbers are the same . That having been said , the proposed project meets the drainage requirements of the City of College Station. No increased peak stormwater flows will be directed to Eagle Avenue, the existing drainage easement and channel, or the receiving storm sewer. APPENDIX A DISCHARGE CALCULATIONS SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT : LOCATION: CLIENT: DRAINAG COMP. BASIN RUNOFF ID COEFF . 1A 0.30 1B 0.30 TOTAL 0.30 1A 0.72 1B 0.30 TOTAL 0 .32 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . BASIN NATURAL WOODLANDS AREA AREA SLOPE RUNOFF <ACRES) <ACRES) <FT/FT) COEFF. EXIST. SITE 0.82 0.00 0.00 0 .00 18 .00 0.00 0.00 0.00 18 .82 0.00 0.00 0.00 PROP. SITE 0 .82 0.00 0.00 0 .00 18.00 0.00 0.00 0.00 18.82 0.00 0.00 0.00 NATURAL GRASSLANDS AREA SLOPE RUNOFF (ACRES) <FT/FT) COEFF . 0.82 0.01 0.30 18.00 0 .01 0 .30 18 .82 0.02 0 .30 0.00 0.00 0.00 18.00 0.01 0.30 18 .00 0.02 0.30 DATE: ENGINEER: DESIGNER: LANDSCAPED AREAS AREA SLOPE RUNOFF (ACRES) <FT/FT) COEFF . 0.00 0.00 0.00 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0 .27 0 .01 0.35 0 .00 0.00 0 .00 0.27 0.01 0.40 PAGE 1-L OF 1 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON IMPERVIOUS AREA SLOPE RUNOFF <ACRES) <FT/FT) COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.55 0.01 0.90 0.00 0.00 0.00 0.55 0.01 0.90 SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION: CLIENT: EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. LOW DENSITY RESIDENT! MED. DENSITY RESIDEN" AREA SLOPE RUNOFF AREA SLOPE RUNOFF <ACRES) <FT/FT) COEFF. <ACRES) (FT/FT) COEFF . 0.00 0.00 0.00 0 .00 0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 HIGH DENSITY RESIDENl AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0 .00 0.00 0.00 DATE : ENGINEER : DESIGNER : BUSINESS I COMMERCIA AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0 .01 0 .00 PAGE 1-R OF 1 06-Jul-OO 0.00 0.00 AREA <ACRES) 0.00 0.00 0.00 0.00 0.00 0.00 INDUSTRIAL SLOPE RUNOFF <FT/FT) COEFF . 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0 .00 O.OQ SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION : CLIENT: DRAINAGI DESIGN BASIN "Tc" ID <MIN) EXIST. 1A 10 .00 1B 35.00 TOTAL 35 .00 PROP . 1A 10 .00 1B 35.00 TOTAL 35.00 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. CALC. NATURAL WOODLANDS "Tc" LENGTH SLOPE VELOCIT (MIN) (FEET) (FT/FT) <FT/SEC) SITE 10.00 0.00 35.00 0.00 35.00 0.00 SITE 1.94 0.00 35.00 0.00 35.00 0.00 DATE: ENGINEER : DESIGNER: NATURAL GRASSLANDS LANDSCAPED AREAS LENGTH SLOPE VELOCIT LENGTH SLOPE VELOCIT (FEET) (FT/FT) (FT/SEC) <FEET) <FT/FT) (FT/SEC) 300 .00 0.01 0.50 0.00 300.00 0.01 0 .50 0.00 300 .00 0.01 0 .50 0.00 0.00 100.00 0.01 2.00 300.00 0.01 0.50 0.00 300.00 0.01 0.50 0.00 PAGE 1-L OF 1 06-Jul-OO 0.00 0.00 LENGTH (FEET) 0.00 0.00 0.00 200 .00 0.00 0.00 PAVEMENT SLOPE <FT/FT) 0.01 VELOCITY (FT/SEC) 3.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT: PIPE LENGTH SLOPE <FEET) (FT/FT) 0 .00 0 .00 0.00 0 .00 0.00 0 .00 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . OPEN CHANNEL VELOCITY LENGTH SLOPE VELOCITY <FT/SEC) (FEET) (FT/FT) <FT/SEC) 0.00 0.00 0 .00 0.00 0 .00 0 .00 NATURAL SWALE LENGTH SLOPE VELOCITY (FEET) (FT/FT) <FT/SEC) 0.00 1500 .00 0 .01 1.00 1500 .00 0 .01 1.00 0.00 1500.00 0 .01 1.00 1500.00 0 .01 1.00 DATE : ENGINEER : DESIGNER : SPREADSHEET 3: BASIN RAINFALL INTENSITY AND DISCHARGE COMPUTATIONS SHEET 1OF1 PROJ ECT: LOCATION : CLIENT: DRAINAG COMP . BAS IN RU NO Fl ID COEFF . 1A 0 .30 1B 0 .30 TOTAL 0 .30 1A 0 .72 1B 0 .30 TOTAL 0 .32 EAGLE AVE . CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . BASIN TIME OF 2YEAR STORM AREA CONC . "I" "Q" (ACRES (MIN) (IN/HR) (CF S ) EXIST. SITE 0 .82 10.00 6 .33 1.56 18 .00 35 .00 3 .14 16.93 18.82 35 .00 3 .14 17 .70 PROP . SITE 0 .82 10.00 6.33 3 .73 18.00 35 .0 0 3 .14 16.93 18 .82 35 .00 3 .14 18.82 5YEAR STORM "I" "Q" (IN/H R) (CFS) 7 .69 1.89 3.93 21 .23 3 .93 22.20 7 .69 4 .53 3.93 21 .23 3 .93 23 .60 10 YEAR STORI "I" "Q" (IN/HR) (CFS) 8 .63 2 .12 4 .50 24.28 4 .50 25 .39 8 .63 5 .09 4 .50 24 .28 4.50 27 .00 DATE: ENGINEER: DESIGNER : 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON 25 YEAR STOR 50 YEAR STORM 100 YEAR STOF "I " "Q" "I" "Q" "I" "Q" <IN/HR) (CFS) (IN/HR) (CFS) <IN/HR) (CFS) 9.86 2.43 11 .15 2.74 11 .64 2 .86 5.18 27 .95 5 .90 31 .84 6 .16 33 .28 5 .18 29 .22 5 .90 33 .29 6 .16 34 .80 9 .86 5.81 11 .15 6 .57 11 .64 6 .86 5 .18 27 .95 5 .90 31 .84 6.16 33 .2 8 5 .18 31 .07 5 .90 35 .39 6 .16 37 .00 APPENDIXB DETENTION CALCULATIONS SPREADSHEET 1: POND STORAGE COMPUTATIONS PROJECT: LOCATION : CLIENT: POINT ELEVA TIC NO. (FEE TI 1 278.00 2 278.50 3 279 .00 4 279.50 5 280.00 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. AVERAGE POND ARE. POND ARE POND ARE (SQ.-FT .l (ACRES) ISQ.-FT.\ 0 .00 0 .00 0 .00 691 .00 0 .02 345.50 3514.00 0 .08 2102 .50 7373.00 0 .17 5443.50 13867.00 0 .32 10620.00 DATE : ENGINEER : DESIGNER : INCR. DEPTH DEPTH IFT.l IFT.l 0 .00 0 .00 0 .50 0 .50 1.00 0 .50 1 .50 0 .50 2 .00 0 .50 INCR. VOLUME ICU .-FT.\ 0 .00 172.75 105125 2721 .75 5310.00 PAGE 1OF1 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON TOTAL INCR. TOTAL VOLUME VOLUME VOLUME ICU .-FT.\ IAC.-FT.\ IAC.-FT.\ 0 .00 0 .00 0.00 172 .75 0 .00 0 .00 1224.00 0 .02 0.03 3945.75 0 .06 0.09 9255.75 0 .12 0 .21 SPREADSHEET 2 : OUTLET WORKS DISCHARGE COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : POND WATER SURFACE POINT ELEVA T l< NO . IFEETl I 1 278.00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. OR IFICE Ni 1 2 AR EA, SF 0 .00 0 .00 INVERT 0 .00 0 .00 Co 0 .00 0 .00 Qo1 CFS Qo2 CFS 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0.00 3 0.00 0.00 0.00 Qo3CFS 0.00 0.00 0.00 0.00 0.00 DATE : ENGINEER: DESIGNER: WE IR NO . 1 LENGTH , I 0 .50 INVERT El 278 .00 Cw 3 .10 Qw1 CFS 0 .00 0 .55 1.55 2.85 4.38 06-Jul-OO ROBERTSON CONSUL TING R. RO BERTSON 2 3 POND 0 .0 0 0 .00 OUT LET 0 .00 0 .00 TOTAL 0 .00 0.00 DISCHAR< Ow2CFS Ow3CFS ICFSI 0 .00 0 .00 0 .00 0 .00 0 .00 0 .55 0 .00 0 .00 1.55 0.00 0.00 2.85 0.00 0.00 4.38 SPREADSHEET 3: 2*S/delta T +OUTFLOW CO MPUTATIONS PROJECT : LOCATION : CLIENT : EAGLE AVE . CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. ENTER COMPUTATION TIME INTERVAL IN MINUTE~ 2.00 STORAGE STORAGE OUTFLOW POINT ELEVA TIC DEPTH ·s· "S" "O" NO . CFEET) CFT .l CCU .-FT .l CAC.-FT .l CCFSl 1 278.00 0.00 0.00 0 .00 0 .00 2 278 .50 0 .50 172 .75 0 .00 0 .55 3 279 .00 1.00 1224.00 0 .03 1.55 4 279 .50 1.50 3945 .75 0.09 2.85 5 280 .00 2.00 9255.75 0.21 4.38 DA TE : 06-Jul-OO ENGINEER ROBERTSON CONSULT ING DESIGNERR. ROBERTSON LOG LOG 2S/dt+O "O" 2S/dt+O ICFSl ICFSl ICFSl 0 .00 0 .00 0 .00 3 .43 -0.26 0 .53 21 .95 0 .19 1.34 68 .61 0 .45 1.84 158.65 0.64 2.20 SPREADSHEET 4a : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO . TIM E INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0 .74 4 1.48 6 2 .22 8 2 .96 10 3 .70 12 2 .96 14 2 .22 16 1.48 18 0 .74 20 0 .01 22 0 .01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BU ILDERS INC. "l"n-1 + "l"n (CFS) 0 .0 0 0 .74 2 .22 3 .70 5 .18 6 .66 6 .66 5 .18 3 .70 2 .22 0 .75 0 .0 2 2YEARSTORM DATE : ENGINEER: DESIGNER: "l"n -1 + "l"n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0 .00 0.00 0.74 -1 .13 1.09 -0 .95 2 .75 0 .23 5 .41 2 .46 9 .12 5 .80 12.46 8.90 14 .08 10.41 14 .11 10 .44 12 .66 9 .08 9 .83 6 .45 6 .47 06-Jul-O O ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0.00 0 .93 1.02 1.26 1.47 1.66 1.78 1.83 1.84 1.79 1.69 1.53 SPREADSHEET 4b : HYDROGRAPH ROUTING COMPUTATI ONS PAGE 1 OF 1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO . T IME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0 .90 4 1.80 6 2.70 8 3.60 10 4.50 12 3 .60 14 2.70 16 1.80 18 0 .90 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 0 .90 2.70 4.50 6 .30 8 .10 8 .10 6 .30 4.50 2.70 0 .91 0 .02 0.02 0 .02 0 .02 0 .02 5 YEA R ST ORM DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0 .00 0 .00 0 .90 -1.05 1.65 -0 .59 3.91 1.17 7 .47 4.30 12 .40 8 .84 16 .94 13 .11 19.41 15.46 19.96 15.99 18.69 14.77 15.68 11 .92 11 .94 8.41 8 .43 5 .17 5 .19 2.27 2.29 -0 .13 -0 .11 07-J u l-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 0 .98 1.12 1.37 1.59 1.78 1.91 1.97 1.99 1.96 1.88 1.77 1.63 1.46 1.21 ERR SPREADSHEET 4c: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l "n (MIN) (CFS) 0 0 .00 2 1.02 4 2 .04 6 3 .06 8 4 .08 10 5 .10 12 4.08 14 3 .06 16 2 .04 18 1.02 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 10 YEAR STORM EAGLE AVE. CH URCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.02 3 .06 5 .10 7 .14 9 .18 9 .18 7 .14 5 .10 3 .06 1.03 0 .02 0 .02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .99 -0 .26 2.05 6 .00 11 .63 17.02 20.25 21 .40 20.54 17.75 14 .10 10.63 7 .35 DATE: ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.02 2 .07 4 .84 9 .19 15.18 20.81 24 .16 25.35 24.46 21 .57 17.77 14 .12 10.65 7 .37 07-Jul-OO ROBE RTSON CONSUL TING R. RO BERTSO N OUTFLOW "O" (CFS) 0 .00 1.00 1.17 1.39 1.60 1.77 1.90 1.96 1.98 1.96 1.91 1.83 1.75 1.65 1.52 SPREADSHEET 4d : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 1.16 4 2.32 6 3.48 8 4.64 10 5.80 12 4.64 14 3.48 16 2 .32 18 1.16 20 0 .01 22 0.01 24 0 .01 26 0 .01 28 0.01 30 0.01 25 YEAR STORM EAGLE AVE. CHU RCH COLLEGE STAT ION , TX STYLECRAFT BUILDERS INC. "l"n -1 + "l"n (CFS) 0 .00 1.16 3 .48 5 .80 8 .12 10.44 10.44 8 .12 5 .80 3 .48 1.17 0 .0 2 0 .02 0 .02 0 .0 2 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .91 0 .09 2 .88 7 .54 14.10 20 .37 24 .18 25.61 . 24 .76 21 .71 17.68 13.83 10.20 6 .81 DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.16 2 .57 5 .89 11 .00 17 .98 24 .54 28.49 29.98 29.09 25.93 2 1.73 17 .70 13.85 10.22 6 .83 07-Jul-OO ROBERTSON CONS UL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 1.03 1.24 1.50 1.73 1.94 2.08 2.16 2 .18 2.17 2 .11 2.03 1.93 1.83 1.70 1.55 SPREADSHEET 4e : HYDROGRAPH ROUTING COMPUTAT IONS PAGE 1 OF 1 PROJECT: LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MI N) (CFS) 0 0 .00 2 1.32 4 2 .64 6 3 .96 8 5 .28 10 6 .60 12 5 .28 14 3 .96 16 2 .64 18 1.32 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 50 YEAR STORM EAGLE AVE. CH URCH COLLEGE STATIO N, TX STYLECRAFT BU ILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.32 3 .96 6 .60 9 .24 11 .88 11 .88 9 .24 6 .60 3 .96 1.33 0 .02 0 .02 0 .02 0 .0 2 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0.81 0 .55 4 .01 9 .63 17.47 25.00 29 .75 31 .79 31 .20 28 .09 23.81 19.69 15 .75 12 .00 DATE : ENGINEER: DESIGNER : "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.32 3 .15 7 .15 13.25 21 .51 29.35 34 .24 36 .35 35 .75 32 .53 28.11 23.83 19.71 15.77 12 .02 07-Jul-O O ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 1.07 1.30 1.57 1.81 2 .02 2 .17 2 .25 2 .28 2 .27 2 .22 2.15 2 .07 1.98 1.88 1.77 SPREADSHEET 4f: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT: LOCATION: CLIENT: INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 1.38 4 2.76 6 4.14 8 5.48 10 6.90 12 5.48 14 4.14 16 2.76 18 1.38 20 0.01 22 0.01 24 0.01 26 0.01 28 0.01 30 0.01 -100 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ·1·n-1 + "l"n (CFS) 0.00 1.38 4.14 6.90 9.62 12.38 12.38 9.62 6.90 4.14 1.39 0.02 0.02 0.02 0.02 0.02 (2S/dT-O)n (CFS) 0.00 0.00 -0.77 0.72 4.44 10.39 18.67 26.66 31.72 33.99 33.52 30.40 26.04 21.83 17.79 13.94 DATE: ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0.00 1.38 3.37 7.62 14.06 22.77 31.05 36.28 38.62 38.13 34.91 30.42 26.06 21.85 17.81 1°3.96 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 1.08 1.32 1.59 1.83 2.05 2.20 2.28 2.31 2.31 2.26 2.19 2.11 2.03 1.94 1.83 DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION July 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 REVIEWED FOR COl\!lPI 1/.\1\ICE JUL 1 7 2000 COLLEGE STAflON ENGINEERIN ~ DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION July 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 CERTIFICATION I hereby certify that this report and accompanying drainage plan for the drainage design of Proposed Eagle Avenue Church was prepared by me in accordance with the provisions of the City of College Station Drainage Polic~ a~d ,Design Standards for the owners thereof ~~~~ ...;;;,_~'r:. ••• ~ .... ~\' ~Ill fu ~ f~i~:.···1\r ···{~~,~· · n ~ ?.;~•ut••'-'·'-~!~t"~!... / . R. G. RO-B c 1~1"0 .! 1 -----~---'-------- 11.: ..... u u •••Ht • .. 9 ""'"."~:=.-· Registered Professional Engineer ~~!-? 5 6S7 S .~:·tff · State of Texas No. 56375 • ~G,-s-1~~:---:.~·t .. ... _,,.,~ o "•••t<••• G~..c;r "St 0 M j\\.. ~-§,.. ~'"""'-' Introduction The proposed project is located on Eagle Avenue immediately west of State Highway 6 in the Springbrook Subdivision. The project consists of a new building and site improvements for a 2.099 acre tract. The site was originally part of a 5.751 acre tract which currently is occupied by Stylecraft Builders Inc. The lot for this project was replatted and separated from the original tract. Figure 1 shows the original drainage map for the Stylecraft project , taken from the drainage report prepared by McClure Engineering Inc . No portion of the project lies within the current boundaries of the regulatory 100-year Floodplain for the City of College Station as shown on Brazos County FIRM #48041 C0205 C. The project lies within the Lick Creek drainage basin . Existing Drainage Patterns The tract and relevant adjacent land areas that contribute runoff to it are undeveloped at this time . Existing land cover consists of natural grasslands . The site receives a substantial amount of off-site flows from areas to the north. The on-site and off-site stormwater flows are discharged to the east into a drainage channel in the adjacent drainage easement on the east side of the property . Proposed Drainage Patterns The proposed drainage patterns and improvements are depicted in Figure 2 . Detailed calculations for the improvements are contained in Appendices A -B. The plans for this project depict the detailed construction necessary to accomplish the proposed drainage improvements and are shown in Exhibit 1. The north area identified as IB will continue to discharge into the channel in the drainage easement on the east side of the property. No detention is needed for this site on the north area, as no new construction on this site will occur. The offsite areas to the north of this tract are assumed to contribute no additional runoff to this site when they are developed . The south area identified as IA represents the developed portion of the tract. Detention is provided for this portion of the site utilizing a portion of the proposed parking area on the southeast comer of the site. The curb will be built higher at the outlet end of the detention area and have a 6" width curb opening discharging into a 2 foot width concrete outlet weir. The detention basin will collect all waters from the developed area of this site and will discharge directly into the existing channel and drainage easement. The detention area is designed to limit the discharge for the 2-year to 100-year storms from the proposed project to less than the discharge that existed prior to construction. Emergency overflow of the detention area will occur over the curb into the channel. The detention basin will pond water to a maximum elevation of 279 .25 feet during the 100-year storm. A combined summary of pre-and post-development peak discharges for the project is provided in Table 1. 2-year 5-year IO-year 25-year 50-year 100-year storm storm storm storm storm storm Existing 1.56 1.89 2 .12 2.43 2 .74 2 .86 Develop 3 .70 4 .50 5 .10 5.80 6 .60 6 .90 Outflow 1.84 1.96 1.98 2 .18 2 .28 2 .31 Table 1. Peak Project Discharges (cfs) Conclusions Although the calculations provided are numerically correct in the application of the principles of hydraulics and hydrology, the actual numbers are below the limits of what is considered the accuracy of the underlying methodology. Calculating discharges to the .01 cfs, .1 cfs, or even 1 cfs, is false accuracy when using any hydrologic method . This site originally discharged about 2-3 cfs over the range of design storms considered . If no detention is provided it will only discharge 4 -7 cfs from the same storms when ultimately developed . The detention provided will reduce that discharge to 2 -3 cfs . Within the accuracy of existing hydrologic methods, these numbers are the same . That having been said, the proposed project meets the drainage requirements of the City of College Station. No increased peak stormwater flows will be directed to Eagle Avenue, the existing drainage easement and channel, or the receiving storm sewer. NV'IdllIS l lJ8IHX:I APPENDIX A DISCHARGE CALCULATIONS SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION : CLIENT: DRAINAG COMP . BASIN RUNOFF ID COEFF . 1A 0 .30 1B 0.30 TOTAL 0 .30 1A 0.72 1B 0.30 TOTAL 0.32 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . BASIN NATURAL WOODLANDS AREA AREA SLOPE RUNOFF (ACRES) (ACRES) (FT/FT) COEFF . EXIST. SITE 0.82 0.00 0.00 0.00 18.00 0.00 0 .00 0 .00 18.82 0.00 0.00 0.00 PROP . SITE 0.82 0.00 0.00 0.00 18.00 0.00 0 .00 0 .00 18.82 0.00 0 .00 0.00 NATURAL GRASSLANDS AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0.82 0.01 0.30 18 .00 0.01 0.30 18.82 0.02 0 .30 0.00 0.00 0.00 18.00 0.01 0.30 18.00 0 .02 0 .30 DATE : ENGINEER: DESIGNER : LANDSCAPED AREAS AREA SLOPE RUNOFF (ACRES) <FT/FT) COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0 .00 0.27 0.01 0.35 0.00 0.00 0.00 0.27 0.01 0.40 PAGE 1-L OF 1 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON IMPERVIOUS AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF. 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0.55 0.01 0.90 0.00 0.00 0.00 0.55 0.01 0.90 SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION : CLIENT: EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . LOW DENSITY RESIDENT! MED . DENSITY RESIDENl AREA SLOPE RUNOFF AREA SLOPE RUNOFF <ACRES) <FT/FT) COEFF . (ACRES) <FT/FT) COEFF . 0.00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0.00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0.00 HIGH DENSITY RESIDENl AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 DATE : ENGINEER: DESIGNER: BUSINESS I COMMERCIA AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF. 0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0 .01 0.00 0.00 0.00 0.00 0.00 0 .00 0 .00 0.00 O.Q1 0.00 PAGE 1-R OF 1 06-Jul-OO 0.00 0.00 INDUSTRIAL AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 O.OQ SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION : CLIENT: DRAINAGI DESIGN BASIN "Tc" ID (MIN) EXIST . 1A 10 .00 1B 35 .00 TOTAL 35 .00 PROP. 1A 10.00 1B 35.00 TOTAL 35 .00 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . CALC . NATURAL WOODLANDS ''Tc" LENGTH SLOPE VELOCIT (MIN) (FEET) (FT/FT) <FT/SEC) SITE 10.00 0.00 35 .00 0 .00 35 .00 0 .00 SITE 1.94 0 .00 35.00 0 .00 35 .00 0.00 DATE: ENGINEER: DESIGNER : NATURAL GRASSLANDS LANDSCAPED AREAS LENGTH SLOPE VELOCIT LENGTH SLOPE VELOCIT (FEET) (FT/FT) (FT/SEC) (FEET) (FT/FT) (FT/SEC) 300.00 0.01 0.50 0.00 300.00 0.01 0.50 0.00 300.00 0.01 0.50 0.00 0.00 100.00 0 .01 2.00 300.00 0 .01 0.50 0.00 300 .00 0.01 0.50 0 .00 PAGE 1-L OF 1 06-Jul-OO 0.00 0.00 LENGTH <FEET) 0 .00 0 .00 0.00 200.00 0.00 0.00 PAVEMENT SLOPE <FT/FT) 0.01 VELOCITY (FT/SEC) 3 .00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT: PIPE LENGTH SLOPE <FEET) (FT/FT) 0 .00 0 .00 0 .00 0.00 0 .00 0.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . OPEN CHANNEL VELOCITY LENGTH SLOPE VELOCITY (FT/SEC) (FEET) (FT/FT) (FT/SEC) 0.00 0 .00 0 .00 0.00 0 .00 0 .00 NATURAL SWALE LENGTH SLOPE VELOCITY (FEET) (FT/FT) <FT/SEC) 0.00 1500.00 0.01 1.00 1500 .00 0 .01 1 .00 0.00 1500.00 0.01 1.00 1500 .00 0 .01 1 .00 DATE: ENGINEER : DESIGNER: SPREADSHEET 3: BASIN RAINFALL INTENSITY AND DISCHARGE COMPUTATIONS SHEET 1OF1 PROJECT: LOCATION : CLIENT: DRAINAG COMP. BASIN RUNOFI ID COEFF. 1A 0 .30 1B 0 .30 TOTAL 0 .30 1A 0 .72 1B 0.30 TOTAL 0 .32 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . BASIN TIMEOI 2YEARSTORM AREA CONC. "I" "Q" (ACRES (MIN) (IN/HR) (CFS) EXIST. SITE 0 .82 10.00 6.33 1.56 18 .00 35.00 3 .14 16.93 18.82 35 .00 3 .14 17.70 PROP. SITE 0 .82 10.00 6 .33 3 .73 18.00 35 .00 3.14 16.93 18.82 35.00 3.14 18.82 5YEAR STORM "I" "Q" (IN/HR) (CFS) 7 .69 1.89 3 .93 21 .23 3 .93 22.20 7 .69 4 .53 3 .93 21.23 3 .93 23 .60 10 YEAR STORI "I" "Q" (IN/HR) (CFS) 8 .63 2.12 4 .50 24.28 4 .50 25.39 8.63 5 .09 4 .50 24.28 4 .50 27 .00 DATE : ENGINEER: DESIGNER: 06-Jul-OO ROBERTSON CONSUL TING R . ROBERTSON 25 YEAR STOR 50 YEAR STORM 100 YEAR STOF "I" "Q" "I" "Q" "I" "Q" (IN/HR) (CFS) (IN/HR) (CFS) (IN/HR) (CFS) 9 .86 2.43 11.15 2 .74 11 .64 2 .86 5 .18 27 .95 5 .90 31 .84 6 .16 33.28 5 .18 29 .22 5.90 33 .29 6 .16 34 .80 9 .86 5 .81 11 .15 6 .57 11 .64 6 .86 5 .18 27 .95 5 .90 31 .84 6 .16 33 .28 5 .18 31 .07 5 .90 35 .39 6 .16 37.00 APPENDIXB DETENTION CALCULATIONS SPREADSHEET 1: POND STORAGE COMPUTATIONS PROJECT: LOCATION : CLIENT: POINT ELEVA TIC NO. (FE En 1 278.00 2 278 .50 3 279.00 4 279 .50 5 280.00 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . AVERAGE POND ARE. POND ARE POND ARE (SQ .-FT.l <ACRES\ lSQ.-FT.l 0 .00 0 .00 0 .00 691 .00 0 .02 345.50 3514.00 0 .08 2102 .50 7373 .00 0 .17 5443 .50 13867.00 0 .32 10620.00 DATE : ENGINEER : DESIGNER : INCR. DEPTH DEPTH <FT .\ <FT .l 0 .00 0 .00 0.50 0 .50 1.00 0 .50 1.50 0 .50 2 .00 0 .50 INCR. VOLUME ICU.-FT.l 0 .00 172 .75 105125 2721 .75 5310.00 PAGE 1OF1 06-Jul--00 ROBERTSON CONSUL TING R. ROBERTSON TOTAL INCR. TOTAL VOLUME VOLUME VOLUME <CU.-FT .l lAC.-FTJ <AC .-FT .l 0 .00 0.00 0 .00 172 .75 0 .00 0 .00 1224.00 0 .02 0 .03 3945 .75 0 .06 0 .09 9255 .75 0 .12 0.21 SPREADSHEET 2: OUTLET WORKS DISCHARGE COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: POND WATER SURFACE POINT ELEVA Tl< NO. !FEETl ' 1 278.00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ORIFICE N1 1 2 AREA, SF 0.00 0.00 INVERT 0.00 0.00 Co 0.00 0.00 Qo1 CFS Qo2 CFS 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3 0.00 0.00 0.00 Qo3CFS 0.00 0.00 0.00 0.00 0.00 DATE: ENGINEER: DESIGNER: WEIR NO. 1 LENGTH, f 0.50 INVERT El 278.00 Cw 3.10 Qw1 CFS 0.00 0.55 1.55 2.85 4.38 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON 2 3 POND 0.00 000 OUTLET 0.00 0.00 TOTAL 0.00 0.00 DISCHARC Qw2 CFS Qw3CFS rcFsl 0.00 0.00 0.00 0.00 0.00 0.55 0.00 0.00 1.55 0.00 0.00 2.85 0.00 0.00 4.38 SPREADSHEET 3 : 2*S/delta T +OUTFLOW COMPUTATIONS PROJECT : LOCATION : CLIENT : EAGLE AVE . CHURCH COLLEGE STAT ION , TX STYLECRAFT BUILDERS INC. ENTER COMPUTAT ION TIME INTERVAL IN MINUTE~ 2.00 STORAGE STORAGE OUTFLOW POINT ELEVA TIC DEPTH ·s· ·s· ·o· NO . IFEETl IFTl ICU .-FT .l IAC.-FT .\ ICFSl 1 278 .00 0 .00 0.00 0 .00 0.00 2 278 .50 0.50 172.75 0 .00 0.55 3 279.00 1.00 1224.00 0 .03 1.55 4 279.50 1.50 3945.75 0 .09 2.85 5 260.00 2 .00 9255.75 0 .21 4.38 DA TE : 06-Jul-OO ENG INEER ROBERTSON CONSUL TING DESIGNERR. RO BERTSON LOG LOG 2S/dt+O "O" 2S/dt+O ICFSl ICFSl ICFSl 0.00 0.00 0 .00 3.43 -0 .26 0 .53 21 .95 0.19 1.34 66 .61 0.45 1.84 158.65 0.64 2 .20 SPREADSHEET 4a : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATIO N : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0 .74 4 1.48 6 2 .22 8 2 .96 10 3 .70 12 2.96 14 2 .22 16 1.48 18 0 .74 20 0 .0 1 22 0 .01 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 0 .74 2 .22 3.70 5.18 6.66 6.66 5.18 3 .70 2.22 0 .75 0 .02 2YEAR STORM DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0.00 0 .00 0 .00 0 .74 -1.13 1.09 -0 .95 2 .75 0 .23 5.41 2 .46 9.12 5 .80 12.46 8 .90 14.08 10.41 14.11 10.44 12 .66 9.08 9 .83 6.45 6 .47 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OU TFLOW ·o· (CFS) 0 .00 0 .93 1.02 1.26 1.47 1.66 1.78 1.83 1.84 1.79 1.69 1.53 SPREADSHEET 4b: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0 .90 4 1.80 6 2.70 8 3 .60 10 4.50 12 3 .60 14 2.70 16 1.80 18 0.90 20 0.01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l "n-1 + "l"n (CFS) 0 .00 0 .90 2.70 4.50 6.30 8.10 8.10 6 .30 4 .50 2 .70 0 .91 0 .02 0 .02 0 .02 0 .02 0 .02 5 YEARSTORM DATE : ENGINEER: DESIGNER: "l"n -1 + ·1·n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0 .00 0 .00 0 .90 -1.05 1.65 -0 .59 3.91 1.17 7 .47 4.30 12 .40 8 .84 16.94 13 .11 19.41 15.46 19.96 15.99 18 .69 14.77 15.68 11 .92 11 .94 8 .41 8 .43 5 .17 5.19 2.27 2.29 -0.13 -0 .11 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 0 .98 1.12 1.37 1.59 1.78 1.91 1.9 7 1.99 1.96 1.88 1.77 1.63 1.46 1.21 ERR SPREADSHEET 4c: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.02 4 2.04 6 3 .06 8 4 .08 10 5 .10 12 4 .08 14 3 .06 16 2 .04 18 1.02 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 10 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.02 3 .06 5 .10 7 .14 9 .18 9 .18 7 .14 5 .10 3 .06 1.03 0 .02 0 .02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .99 -0 .26 2 .05 6 .00 11 .63 17.02 20.25 21 .40 20.54 17.75 14 .10 10 .63 7.35 DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.02 2.07 4 .84 9 .19 15 .18 20 .81 24 .16 25 .35 24.46 21 .57 17.77 14 .12 10.65 7 .37 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 1.00 1.17 1.39 1.60 1.77 1.90 1.96 1.98 1.96 1.91 1.83 1.75 1.65 1.52 SPREADSHEET 4d: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 1.16 4 2.32 6 3.48 8 4.64 10 5 .80 12 4 .64 14 3 .48 16 2 .32 18 1.16 20 0.0 1 22 0 .0 1 24 0 .0 1 26 0 .0 1 28 0 .01 30 0 .0 1 25 YEAR STORM EAGLE AV E. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.16 3 .48 5 .80 8 .12 10.44 10.44 8 .12 5 .80 3 .48 1.17 0 .02 0.02 0.02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0.91 0 .09 2 .88 7 .54 14.10 20.37 24.18 25.61 24 .76 2 1.71 17.68 13.83 10.20 6 .81 DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.16 2 .57 5 .89 11 .00 17.98 24.54 28.49 29.98 29.09 25.93 21 .73 17.70 13.85 10.22 6 .83 07-J ul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 1.03 1.24 1.50 1.73 1.94 2 .08 2 .16 2 .18 2.17 2 .11 2 .03 1.93 1.83 1.70 1.55 SPREADSHEET 4e : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT: LOCATIO N : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (M IN) (CFS) 0 0 .00 2 1.32 4 2.64 6 3.96 8 5.28 10 6.60 12 5 .28 14 3 .96 16 2 .64 18 1.32 20 O.Q1 22 0 .01 24 0.D1 26 0 .01 28 0 .01 30 0 .01 50 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n -1 + "l"n (CFS) 0 .00 1.32 3 .96 6 .60 9 .24 11 .88 11 .88 9 .24 6 .60 3 .96 1.33 0 .02 0 .02 0 .02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .81 0 .55 4 .01 9 .63 17.47 25.00 29.75 31 .79 31 .20 28 .09 23.81 19.69 15.75 12 .00 DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.32 3 .15 7 .15 13 .25 2 1.51 29 .35 34 .24 36 .35 35 .75 32 .53 28 .11 23 .83 19 .71 15 .77 12 .02 07.Jul-O O ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 1.07 1.30 1.57 1.81 2.02 2 .17 2 .25 2.28 2.27 2 .22 2.15 2 .0 7 1.98 1.88 1.77 SPREADS H EET 4f: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF1 PRO JECT : LOCATION : CLIENT : INFLOV HYDRO. TI ME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.38 4 2 .76 6 4 .14 8 5.48 10 6.90 12 5 .48 14 4.14 16 2 .76 18 1.38 20 0 .0 1 22 0 .01 24 0 .0 1 26 0 .01 28 0 .0 1 30 0 .01 -100 YEAR STORM EAG LE AVE. CHURCH COLLEGE STATION, TX S TYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.38 4 .14 6 .90 9 .62 12.38 12 .38 9 .62 6 .90 4 .14 1.39 0 .02 0 .02 0 .02 0 .02 0 .0 2 (2S/dT-O)n (CFS) 0 .00 000 -0.77 0 .72 4 .44 10.39 18.67 26 .66 31 .72 33 .99 33 .52 30 .40 26 .04 21 .83 17.79 13.94 DATE: ENGINEER : DES IGNER : "l"n-1 + "l"n + (2S/dT-O)n (C FS) 0 .00 1 .38 3.37 7 .62 14.06 22 .77 31 .05 36.28 38.62 38 .13 34.91 30 .42 26.06 21 .85 17.81 13 .96 07-J ul-O O ROBERTSO N CONSUL T ING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 1.08 1.32 1.59 1.83 2 .05 2.20 2.28 2 .31 2 .31 2 .26 2 .19 2 .11 2.03 1 .94 1.83 DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION July 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 REVIEWED FOR { co~~PI IANCE JUL 1 7 2000 COLLEGE STATION ENGINEERING ~ DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION July 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 CERTIFICATION I hereby certify that this report and accompanying drainage plan for the drainage design of Proposed Eagle A venue Church was prepared by me in accordance with the provisions of the City of College Station Drainage Po~Design Standards for the owners thereof. ~-~\.~: .. ~~'.~~. tu ~ .-t'.~r .• • "• ~ ~ ~~)~·· -;'~· ··;~$' ~~ ~ '-'*· .-¢':.&• (; .. . ·~·1 . /7 f .f-k.°G.~R'o8£R1saU··· ~ _____ ._L __ .._ ______ _ 'li.l ; .... Hd•••u:.ue·vc-..·:.; .. ~ Registered Professional Engineer ~1>':.0.;'9-~~0~7S<-i.~1f?· State of Texas No. 56375 ".<-···!, t s11'.:;·"<.-..-ff ~~3 •••·u ·••• ~:._~ "~Q~_A\..,_~ ·~~-- Introduction The proposed project is located on Eagle Avenue immediately west of State Highway 6 in the Springbrook Subdivision . The project consists of a new building and site improvements for a 2. 099 acre tract. The site was originally part of a 5. 7 51 acre tract which currently is occupied by Stylecraft Builders Inc. The lot for this project was replatted and separated from the original tract . Figure 1 shows the original drainage map for the Stylecraft project , taken from the drainage report prepared by McClure Engineering Inc . No portion of the project lies within the current boundaries of the regulatory 100-year Floodplain for the City of College Station as shown on Brazos County FIRM #48041 C0205 C. The project lies within the Lick Creek drainage basin. Existing Drainage Patterns The tract and relevant adjacent land areas that contribute runoff to it are undeveloped at this time . Existing land cover consists of natural grasslands . The site receives a substantial amount of off-site flows from areas to the north . The on-site and off-site stormwater flows are discharged to the east into a drainage channel in the adjacent drainage easement on the east side of the property. Proposed Drainage Patterns The proposed drainage patterns and improvements are depicted in Figure 2 . Detailed calculations for the improvements are contained in Appendices A -B. The plans for this project depict the detailed construction necessary to accomplish the proposed drainage improvements and are shown in Exhibit 1. The north area identified as IB will continue to discharge into the channel in the drainage easement on the east side of the property. No detention is needed for this site on the north area, as no new construction on this site will occur. The offsite areas to the north of this tract are assumed to contribute no additional runoff to this site when they are developed . The south area identified as IA represents the developed portion of the tract. Detention is provided for this portion of the site utilizing a portion of the proposed parking area on the southeast comer of the site . The curb will be built higher at the outlet end of the detention area and have a 6" width curb opening discharging into a 2 foot width concrete outlet weir. The detention basin will collect all waters from the developed area of this site and will discharge directly into the existing channel and drainage easement. The detention area is designed to limit the discharge for the 2-year to 100-year storms from the proposed project to less than the discharge that existed prior to construction. Emergency overflow of the detention area will occur over the curb into the channel. The detention basin will pond water to a maximum elevation of 279 .25 feet during the 100-year storm. A combined summary of pre-and post-development peak discharges for the project is provided in Table 1. Li n LJ u 2-year 5-year 10-year 25-year 50-year 100-year storm storm storm storm storm storm Existing 1.56 1.89 2.12 2.43 2.74 2.86 Develop 3.70 4.50 5.10 5.80 6.60 6.90 Outflow 1.84 1.96 1.98 2.18 2.28 2.31 Table 1. Peak Project Disch arges (cfs) Conclusions Although the calculations provided are numerically correct in the application of the principles of hydraulics and hydrology, the actual numbers are below the limits of what is considered the accuracy of the underlying methodology. Calculating discharges to the .01 cfs, .1 cfs, or even 1 cfs, is false accuracy when using any hydrologic method. This site originally discharged about 2-3 cfs over the range of design storms considered. If no detention is provided it will only discharge 4 - 7 cfs from the same storms when ultimately developed. The detention provided will reduce that discharge to 2 - 3 cfs. Within the accuracy of existing hydrologic methods, these numbers are the same. That having been said, the proposed project meets the drainage requirements of the City of College Station. No increased peak stormwater flows will be directed to Eagle Avenue, the existing drainage easement and channe~ or the receiving storm sewer. I I I I I I I I I I I I I I I I I I I EXHIBIT1 SITE PLAN APPENDIX A DISCHARGE CALCULATIONS SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION : CLIENT: DRAINAG COMP. BASIN RUNOFF ID COEFF. 1A 0 .30 1B 0 .30 TOTAL 0.30 1A 0.72 1B 0.30 TOTAL 0.32 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . BASIN NATURAL WOODLANDS AREA AREA SLOPE RUNOFF (ACRES) <ACRES) <FT/FT) COEFF . EXIST. SITE 0.82 0.00 0 .00 0 .00 18.00 0.00 0.00 0.00 18 .82 0.00 0.00 0.00 PROP. SITE 0 .82 0 .00 0 .00 0 .00 18 .00 0.00 0.00 0.00 18.82 0.00 0.00 0.00 NATURAL GRASSLANDS AREA SLOPE RUNOFF (ACRES) <FT/FT) COEFF . 0.82 0.01 0.30 18.00 0.01 0 .30 18 .82 0.02 0.30 0.00 0.00 0.00 18 .00 0.01 0.30 18.00 0.02 0.30 DATE: ENGINEER: DESIGNER: LANDSCAPED AREAS AREA SLOPE RUNOFF (ACRES) <FT/FTl COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .27 0.01 0.35 0.00 0.00 0.00 0 .27 0.01 0.40 PAGE 1-L OF 1 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON IMPERVIOUS AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.55 0.01 0.90 0.00 0.00 0.00 0.55 0.01 0.90 SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION : CLIENT: EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. LOW DENSITY RESIDENT! MED . DENSITY RESIDENl AREA SLOPE RUNOFF AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . (ACRES) (FT/FT) COEFF . 0.00 0.00 0.00 0.00 0.00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0.00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 HIGH DENSITY RESIDENl AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0.00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 DATE : ENGINEER: DESIGNER: BUSINESS I COMMERCIA AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0.00 0.00 0 .00 0 .00 0.00 0.00 0 .00 0 .01 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0 .00 0.01 0.00 PAGE 1-R OF 1 06-Jul-OO 0.00 0.00 AREA (ACRES) 0.00 0.00 0.00 0.00 0.00 0.00 INDUSTRIAL SLOPE RUNOFF (FT/FT) COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 O.OQ SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT: DRAINAG DESIGN BASIN "Tc" ID (MIN) EXIST. 1A 10.00 1B 35 .00 TOTAL 35 .00 PROP. 1A 10 .00 1B 35.00 TOTAL 35.00 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . CALC . NATURAL WOODLANDS "Tc" LENGTH SLOPE VELOCIT (MIN) (FEET) (FT/FT) (FT/SEC) SITE 10.00 0 .00 35 .00 0 .00 35.00 0.00 SITE 1.94 0 .00 35.00 0.00 35.00 0.00 DATE: ENGINEER : DESIGNER : NATURAL GRASSLANDS LANDSCAPED AREAS LENGTH SLOPE VELOCIT LENGTH SLOPE VELOCIT (FEET) (FT/FT) (FT/SEC) (FEET) (FT/FT) (FT/SEC) 300 .00 0 .01 0 .5 0 0 .00 300.00 0 .01 0 .50 0 .00 300.00 0 .01 0 .50 0.00 0.00 100.00 0 .01 2.00 300 .00 0.01 0.50 0 .00 300.00 0.01 0.50 0.00 PAGE 1-L OF 1 06-Jul-OO 0.00 0 .00 LENGTH (FEET) 0.00 0.00 0 .00 200 .00 0.00 0.00 PAVEMENT SLOPE <FT/FT) 0 .01 VELOCITY <FT/SEC) 3.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION : CLIENT : PIPE LENGTH SLOPE <FEET) (FT/FT) 0.00 0 .00 0.00 0 .00 0 .00 0 .00 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . OPEN CHANNEL VELOCITY LENGTH SLOPE VELOCITY (FT/SEC) (FEET) (FT/FT) (FT/SEC) 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 NATURAL SWALE LENGTH SLOPE VELOCITY (FEET) (FT/FT) (FT/SEC) 0 .00 1500.00 0 .01 1 .00 1500 .00 0 .01 1.00 0.00 1500.00 0 .01 1.00 1500 .00 0.01 1 .00 DATE : ENGINEER: DESIGNER: SPREADSHEET 3: BASIN RAINFALL INTENSITY AND DISCHARGE COMPUTATIONS SHEET 1OF1 PROJECT: LOCATION : CLIENT: DRAINAG COMP . BASIN RUNOFI ID COEFF . 1A 0 .30 1B 0 .30 TOTAL 0 .30 1A 0 .72 1B 0 .30 TOTAL 0 .32 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . BASIN TIME Of 2YEARSTORM AREA CONC . "I" "Q" (ACRES (MIN) (IN/HR) (CFS) EXIST. SITE 0 .82 10.00 6 .33 1.56 18.00 35 .00 3 .14 16 .93 18 .82 35 .00 3.14 17.70 PROP. SITE 0.82 10.00 6 .33 3.73 18.00 35 .00 3.14 16.93 18.82 35 .00 3.14 18 .82 5 YEAR STORM "I" "Q" ON/HR) (CFS) 7 .69 1.89 3 .93 21.23 3 .93 22 .20 7 .69 4 .53 3 .93 21 .23 3 .93 23 .60 10YEAR STOR "I" "Q" ON/HR) (CFS) 8 .63 2 .12 4 .50 24 .28 4 .50 25 .39 8 .63 5.09 4.50 24 .28 4 .50 27 .00 DATE : ENGINEER : DESIGNER : 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON 25 YEAR STOR 50 YEAR STORM 100 YEAR STOI "I" "Q" "I" "Q" "I" 11011 (IN/HR) (CFS) flN/HR) (CFS) (IN/HR) (CFS\ 9 .86 2.43 11 .15 2 .74 11.64 2 .86 5 .18 27.95 5 .90 31 .84 6 .16 33 .28 5 .18 29.22 5 .90 33 .29 6 .16 34.80 9.86 5 .81 11 .15 6 .57 11 .64 6 .86 5.18 27.95 5.90 31 .84 6 .16 33.28 5.18 31 .07 5.90 35 .39 6 .16 37 .00 APPENDIXB DETENTION CALCULATIONS SPREADSHEET 1: POND STORAGE COMPUTATIONS PROJECT: LOCATION : CLIENT : POINT ELEVA TIC NO. IFEETI 1 278.00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. AVERAGE PONDAREi POND ARE POND ARE ISQ.-FT.l (ACRES) (SQ .-FT.l 0 .00 0 .00 0 .00 691 .00 0.02 345.50 3514.00 0 .08 2102 .50 7373.00 0 .17 5443.50 13867.00 0 .32 10620.00 DATE : ENGINEER : DESIGNER: INCR. DEPTH DEPTH <FT .l IFT.l 0.00 0.00 0.50 0 .50 1.00 0.50 1.50 0 .50 2 .00 0 .50 INCR. VOLUME ICU.-FT .l 0 .00 172 .75 1051 .25 2721 .75 5310.00 PAGE 1OF1 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON TOTAL INCR. TOTAL VOLUME VOLUME VOLUME ICU.-FT .l IAC.-FT.l (AC.-FT .l 0 .00 0 .00 0.00 172 .75 0 .00 0 .00 1224.00 0 .02 0.03 3945.75 0.06 0.09 9255 .75 0 .12 0 .21 SPREADSHEET 2 : OUTLET W ORKS DISCHARGE COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : POND WATER SURFACE POINT ELEVA TIC NO. IFEETl 1 278 .00 2 278 .50 3 279.00 4 279.50 5 280.00 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BU ILDERS INC. ORIFICE N< 1 2 AREA, SF 0 .00 0 .00 INVERT 0 .00 0 .00 Co 0 .00 0 .00 Qo1 CFS Qo2 CFS 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 3 0.00 0.00 0 .00 Qo3CFS 0 .00 0 .00 0 .00 0 .00 0.00 DATE: ENGINEER: DESIGNER : WEIR NO. 1 LENGTH , I 0 .50 INVERT El 278.00 Cw 3 .10 Qw1 CFS 0 .00 0.55 1.55 2.85 4 .38 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON 2 3 POND 0 .00 0 .00 OUTLET 0 .00 0 .00 TOTAL 0 .00 0 .00 DISCHARC Qw2 CFS Qw3CFS ICFS\ 0 .00 0 .00 0 .00 0 .00 0 .00 0 .55 0 .00 0.00 1 .55 0 .00 0 .00 2 .85 0 .00 0 .00 4 .38 SPREADSHEET 3 : 2*S/delta T +OUTFLOW COMPUTATIONS PROJECT : LOCAT ION : CLIENT : EAGLE AVE . CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. ENTER COMPUTATION T IME INTERVAL IN MINUTE~ 2.00 STORAGE STORAGE OUTFLOW POINT ELEVA Tl< DEPTH ·s· ·s· "O" NO . IFEETl IFT .l ICU.-FT .l IAC.-FT .l /CFS\ 1 278 .00 0 .00 0.00 0 .00 0.00 2 278 .50 0.50 172.75 0.00 0.55 3 279 .00 1.00 1224.00 0.03 1.55 4 279 .50 1.50 3945 .75 0.09 2.85 5 280 .00 2.00 9255.75 0.21 4.38 DATE : 06 -Jul-OO ENGINEER ROBERTSON CONSULTING DESIGNERR. ROBERTSON LOG LOG 2S/dt+O ·o· 2S/dt+O ICFS\ ICFS\ ICFS\ 0.00 0.00 0.00 3.43 -0 .26 0.53 21 .95 0.19 1.34 68 .61 0.45 1.84 158.65 0.64 2.20 SPREADSHEET 4a: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT: LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0.74 4 1.48 6 2.22 8 2 .96 10 3 .70 12 2 .96 14 2 .22 16 1.48 18 0.74 20 0.01 22 0.01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 0 .74 2 .22 3 .70 5 .18 6 .66 6 .66 5 .18 3 .70 2.22 0 .75 0 .02 2 YEAR STORM DATE : ENGINEER : DESIGNER : "l"n-1 + "l"n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0.00 0 .00 0 .74 -1.13 1.09 -0 .95 2.75 0 .23 5.41 2 .46 9 .12 5 .80 12.46 8 .90 14.08 10.41 14.11 10.44 12 .66 9 .08 9.83 6 .45 6.47 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 0 .93 1.02 1.26 1.47 1.66 1.78 1.83 1.84 1.79 1.69 1.53 SPREADSHEET 4b: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0 .90 4 1.80 6 2.70 8 3 .60 10 4.50 12 3 .60 14 2.70 16 1.80 18 0.90 20 0 .01 22 0 .01 24 0.01 26 0 .01 28 0 .01 30 0.01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 .. "l"n (CFS) 0 .00 0.90 2.70 4.50 6.30 8.10 8.10 6 .30 4.50 2.70 0 .91 0.02 0.02 0.02 0.02 0.02 5 YEAR STORM DATE : ENGINEER : DESIGNER : "l "n-1 .. "l"n .. (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0 .00 0 .00 0 .90 -1.05 1.65 -0 .59 3.91 1.17 7 .47 4.30 12.40 8 .84 16.94 13.11 19.41 15.46 19.96 15 .99 18.69 14.77 15.68 11 .92 11 .94 8 .41 8 .43 5 .17 5.19 2.27 2.29 -0 .13 -0 .11 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 0 .98 1.12 1.37 1.59 1.78 1.91 1.97 1.99 1.96 1.88 1.77 1.63 1.46 1.21 ERR SPREAD SHEET 4c: HYDROGRAPH ROU TI NG COMPUTATIONS PAGE 1 OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.02 4 2.04 6 3 .06 8 4.08 10 5 .10 12 4.08 14 3 .06 16 2.04 18 1.02 20 0.01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 10 YEAR STORM EAGLE AVE . CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.02 3 .06 5.10 7 .14 9.18 9 .18 7 .14 5 .10 3 .06 1.03 0.02 0.02 0.02 0.02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .99 -0 .26 2.05 6 .00 11 .63 17.02 20 .25 21.40 20.54 17 .75 14 .10 10.63 7 .35 DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.02 2.07 4.84 9 .19 15.18 20.81 24 .16 25 .35 24 .46 21 .57 17 .77 14 .12 10.65 7.37 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 1.00 1.17 1.39 1.60 1.77 1.90 1.96 1.98 1.96 1.91 1.83 1.75 1.65 1.52 SPREADSHEET 4d : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.16 4 2 .32 6 3.48 8 4 .64 10 5 .80 12 4 .64 14 3 .48 16 2 .32 18 1.16 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 25 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.16 3 .48 5 .80 8 .12 10.44 10.44 8 .12 5 .80 3 .48 1.17 0 .02 0 .02 0 .02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 --0 .91 0 .09 2.88 7.54 14 .10 20 .37 24 .18 25 .61 . 24 .76 21 .71 17.68 13.83 10.20 6 .81 DATE : ENGINEER : DESIGNER : "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.16 2.57 5 .89 11 .00 17.98 24 .54 28.49 29.98 29.09 25.93 21 .73 17.70 13.85 10.22 6 .83 07-Jul--OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 1.03 1.24 1.50 1.73 1.94 2 .08 2 .16 2 .18 2 .17 2 .11 2 .03 1.93 1.83 1.70 1.55 SPREADSHEET 4e : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.32 4 2 .64 6 3 .96 8 5 .28 10 6 .60 12 5 .28 14 3 .96 16 2 .64 18 1.32 20 0 .01 22 0 .01 24 0.01 26 0.01 26 0 .01 30 0 .01 50 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.32 3.96 6 .60 9 .24 11 .86 11.88 9 .24 6 .60 3 .96 1.33 0 .02 0 .02 0 .02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .81 0 .55 4.01 9.63 17 .47 25 .00 29 .75 31 .79 31 .20 26 .09 23 .61 19.69 15 .75 12 .00 DATE : ENGINEER: DESIGNER : "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.32 3 .15 7 .15 13 .25 21 .51 29 .35 34 .24 36 .35 35 .75 32 .53 26.11 2 3.63 19 .71 15.77 12 .02 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 1.07 1.30 1.57 1.81 2 .02 2 .17 2 .25 2 .28 2.27 2.22 2.15 2 .07 1.98 1.68 1.77 SPREADSHEET 4f: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 1.38 4 2.76 6 4.14 8 5.48 10 6.90 12 5.48 14 4.14 16 2.76 18 1.38 20 0.01 22 0.01 24 0.01 26 0.01 28 0.01 30 0.01 -100 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0.00 1.38 4.14 6.90 9.62 12.38 12.38 9.62 6.90 4.14 1.39 0.02 0.02 0.02 0.02 0.02 (2S/dT-O)n (CFS) 0.00 0.00 -0.77 0.72 4.44 10.39 18.67 26.66 31.72 33.99 33.52 30.40 26.04 21.83 17.79 13.94 DATE: ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0.00 1.38 3.37 7.62 14.06 22.77 31.05 36.28 38.62 38.13 34.91 30.42 26.06 21.85 17.81 13.96 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 1.08 1.32 1.59 1.83 2.05 2.20 2.28 2.31 2.31 2.26 2.19 2.11 2.03 1.94 1.83 DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION July 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 REVIEWED FOR , CO~API fllNCE JUL 1 7 2000 COLLEGE STAflOl'J ENGINEERIN~~ DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION July 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 CERTIFICATION I hereby certify that this report and accompanying drainage plan for the drainage design of Proposed Eagle Avenue Church was prepared by me in accordance with the provisions of the City of College Station Drainage Po~~d Design Standards for the owners thereof ~-:;; ... {:,;; ~~- ...::;;_,'r:. ···•·•.'.~.~ 4r~ iv ~~'· t!,&• I~ "• .. "'/ ,";~ f!p ff>-f:~~·· 1~ ·-;~~).). . J7 ~ -~k·G.'R'o8'£·RfsoU ... I _____ L_.L __ _.__ ______ _ ; ..... ,u•••u:•-•••·"'·~·=.:-r. Registered P rofessional Engineer ~-n~0 -9: 56375 ,~:/yf;-State of Texas No. 56375 1>"···~6 ,·s-~~~~"~1:' -<'-•, I \ •• _,(.,__, ~s ····'"···· ~~~ ' "-![Q ~_A.\.. _,...,,=-·~-..-....-- Introduction The proposed project is located on Eagle Avenue immediately west of State Highway 6 in the Springbrook Subdivision. The project consists of a new building and site improvements for a 2 . 099 acre tract. The site was originally part of a 5. 7 51 acre tract which currently is occupied by Stylecraft Builders Inc . The lot for this project was replatted and separated from the original tract. Figure 1 shows the original drainage map for the Stylecraft project, taken from the drainage report prepared by McClure Engineering Inc . No portion of the project lies within the current boundaries of the regulatory 100-year Floodplain for the City of College Station as shown on Brazos County FIRM #48041 C0205 C. The project lies within the Lick Creek drainage basin. Existing Drainage Patterns The tract and relevant adjacent land areas that contribute runoff to it are undeveloped at this time . Existing land cover consists of natural grasslands . The site receives a substantial amount of off-site flows from areas to the north . The on-site and off-site stormwater flows are discharged to the east into a drainage channel in the adjacent drainage easement on the east side of the property. Proposed Drainage Patterns The proposed drainage patterns and improvements are depicted in Figure 2 . Detailed calculations for the improvements are contained in Appendices A -B . The plans for this project depict the detailed construction necessary to accomplish the proposed drainage improvements and are shown in Exhibit 1. The north area identified as lB will continue to discharge into the channel in the drainage easement on the east side of the property. No detention is needed for this site on the north area, as no new construction on this site will occur. The offsite areas to the north of this tract are assumed to contribute no additional runoff to this site when they are developed . The south area identified as IA represents the developed portion of the tract. Detention is provided for this portion of the site utilizing a portion of the proposed parking area on the southeast comer of the site . The curb will be built higher at the outlet end of the detention area and have a 6" width curb opening discharging into a 2 foot width concrete outlet weir . The detention basin will collect all waters from the developed area of this site and will discharge directly into the existing channel and drainage easement. The detention area is designed to limit the discharge for the 2-year to 100-year storms from the proposed project to less than the discharge that existed prior to construction. Emergency overflow of the detention area will occur over the curb into the channel. The detention basin will pond water to a maximum elevation of 279 .25 feet during the 100-year storm. A combined summary of pre-and post-development peak discharges for the project is provided in Table 1. 2-year 5-year 10-year 25-year 50-year 100-year storm storm storm storm storm storm Existing 1.56 1.89 2 .12 2.43 2 .74 2.86 Develop 3 .70 4.50 5 .10 5.80 6.60 6 .90 Outflow 1.84 1.96 1.98 2 .18 2 .28 2 .31 Table 1. Peak Project Discharges (cfs) Conclusions Although the calculations provided are numerically correct in the application of the principles of hydraulics and hydrology, the actual numbers are below the limits of what is considered the accuracy of the underlying methodology. Calculating discharges to the .01 cfs, .1 cfs , or even 1 cfs, is false accuracy when using any hydrologic method. This site originally discharged about 2-3 cfs over the range of design storms considered. If no detention is provided it will only discharge 4 - 7 cfs from the same storms when ultimately developed . The detention provided will reduce that discharge to 2 -3 cfs. Within the accuracy of existing hydrologic methods, these numbers are the same . That having been said, the proposed project meets the drainage requirements of the City of College Station. No increased peak stormwater flows will be directed to Eagle Avenue, the existing drainage easement and channel, or the receiving storm sewer . l .LI8IHX:I APPENDIX A DISCHARGE CALCULATIONS SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION : CLIENT: DRAINAGI COMP . BASIN RUNOFF ID COEFF. 1A 0.30 1B 0.30 TOTAL 0.30 1A 0.72 1B 0 .30 TOTAL 0.32 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. BASIN NATURAL WOODLANDS AREA AREA SLOPE RUNOFF (ACRES) (ACRES) (FT/FT) COEFF. EXIST. SITE 0.82 0.00 0.00 0.00 18.00 0.00 0.00 0 .00 18.82 0.00 0.00 0.00 PROP. SITE 0.82 0.00 0.00 0.00 18.00 0.00 0.00 0.00 18.82 0 .00 0.00 0 .00 NATURAL GRASSLANDS AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF. 0 .82 0.01 0 .30 18 .00 0.01 0.30 18.82 0 .02 0.30 0.00 0.00 0.00 18 .00 0 .01 0.30 18 .00 0.02 0.30 DATE: ENGINEER: DESIGNER: LANDSCAPED AREAS AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0 .00 0.00 0.00 0 .00 0 .00 0.00 0.00 0.00 0.00 0.27 0.01 0.35 0.00 0.00 0.00 0 .27 0.01 0.40 PAGE 1-L OF 1 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON IMPERVIOUS AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.55 0.01 0.90 0.00 0.00 0.00 0.55 0.01 0.90 SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION : CLIENT : EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . LOW DENSITY RESIDENT! MED. DENSITY RESIDEN" AREA SLOPE RUNOFF AREA SLOPE RUNOFF <ACRES) <FT/FT) COEFF . (ACRES) (FT/FT) COEFF . 0.00 0.00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0.00 0.00 0.00 HIGH DENSITY RESIDENl AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF . 0.00 0.00 0.00 0.00 0 .00 0.00 0 .00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 DATE : ENGINEER: DESIGNER: BUSINESS I COMMERCIA AREA SLOPE RUNOFF (ACRES) lFT/FT) COEFF . 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.01 0.00 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0.01 0.00 PAGE 1-R OF 1 06-Jul-OO 0.00 0.00 AREA <ACRES) 0.00 0.00 0.00 0.00 0.00 0.00 INDUSTRIAL SLOPE RUNOFF (FT/FT) COEFF . 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT: DRAINAG DESIGN BASIN "Tc" ID (MIN) EXIST. 1A 10 .00 1B 35.00 TOTAL 35 .00 PROP. 1A 10 .00 1B 35 .00 TOTAL 35 .00 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . CALC. NATURAL WOODLANDS "Tc" LENGTH SLOPE VELOCIT (MIN) (FEET) (FT/FT) (FT/SEC) SITE 10.00 0.00 35.00 0.00 35 .00 0.00 SITE 1.94 0.00 35.00 0.00 35.00 0.00 DATE : ENGINEER: DESIGNER: NATURAL GRASSLANDS LANDSCAPED AREAS LENGTH SLOPE VELOCIT LENGTH SLOPE VELOCIT (FEET) (FT/FT) (FT/SEC) (FEET) (FT/FT) (FT/SEC) 300 .00 0 .01 0.50 0.00 300 .00 0.01 0.50 0.00 300 .00 0.01 0.50 0.00 0.00 100 .00 0.01 2 .00 300 .00 0 .01 0.50 0.00 300.00 0.01 0.50 0.00 PAGE 1-L OF 1 06-Jul-OO 0.00 0.00 LENGTH (FEET) 0.00 0.00 0.00 200 .00 0.00 0.00 PAVEMENT SLOPE (FT/FTI 0.01 VELOCITY (FT/SEC) 3.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION : CLIENT: PIPE LENGTH SLOPE (FEET) (FT/FT) 0.00 0 .00 0 .00 0.00 0 .00 0 .00 EAGLE AVE . CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . OPEN CHANNEL VELOCITY LENGTH SLOPE VELOCITY (FT/SEC) (FEET) (FT/FT) (FT/SEC) 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 NATURAL SWALE LENGTH SLOPE VELOCITY (FEET) (FT/FT) (FT/SEC) 0 .00 1500.00 0 .01 1.00 1500.00 0 .01 1.00 0.00 1500 .00 0 .01 1.00 1500.00 0 .01 1.00 DATE: ENGINEER: DESIGNER : SPREADSHEET 3 : BASIN RAINFALL INTENSITY AND DISCHARGE COMPUTATIONS SHEET 1OF1 PROJECT: LOCATION : CLIENT: DRAINAG COMP . BASIN RUNOF ID COEFF . 1A 0 .30 1B 0 .30 TOTAL 0 .30 1A 0 .72 1B 0 .30 TOTAL 0 .32 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. BASIN TIME Of 2YEARSTORM AREA CONC . "I .. "Q" <A CR E S <MIN) <IN/HR) <CFS) EXIST . SITE 0 .82 10.00 6.33 1.56 18.00 35.00 3.14 16.93 18.82 35 .00 3.14 17.70 PROP. SITE 0.82 10.00 6 .33 3.73 18.00 35 .00 3.14 16.93 18.82 35 .00 3.14 18.82 5YEAR STORM "I" "Q" (IN/HR) <CFS) 7 .69 1.89 3.93 21 .23 3 .93 22.20 7 .69 4 .53 3.93 21 .23 3.93 23.60 10 YEAR STORI "I" "Q" (IN/HR) (CFS) 8 .63 2 .12 4 .50 24 .28 4 .50 25.39 8 .63 5 .09 4 .50 24 .28 4 .50 27.00 DATE : ENGINEER : DESIGNER : 06-Jul-OO ROBERTSON CONSUL TING R . RO BERTSON 25YEAR STOR 50 YEAR STORM 100 YEAR STOf "I" "Q" "I" "Q" 11111 "Q" (IN/HR) <CF S) <IN/HR) <C FS) <IN/HR) <CFS) 9 .86 2.43 11.15 2.74 11 .64 2 .86 5 .18 27.95 5 .90 31 .84 6.16 33 .28 5.18 29.22 5 .90 33 .29 6 .16 34 .80 9 .86 5 .81 11 .15 6 .57 11 .64 6.86 5 .18 27 .95 5 .90 31 .84 6 .16 33 .28 5 .18 31 .07 5 .90 35 .39 6 .16 37 .00 APPENDIXB DETENTION CALCULATIONS SPREADSHEET 1: POND STORAGE COMPUTATIONS PROJECT: LOCATION : CLIENT: POINT ELEVA TIC NO. (FE En 1 278 .00 2 278 .50 3 279 .00 4 279 .50 5 280 .00 EAGLE AVE . CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . AVERAGE POND ARE.I POND ARE POND ARE (SQ .-FT.l (ACRES\ CSQ .-FT.l 0 .00 0.00 0 .00 691 .00 0 .02 345.50 3514.00 0.08 2102 .50 7373 .00 0 .17 5443.50 13867 .00 0 .32 10620.00 DATE : ENGINEER: DESIGNER: INCR. DEPTH DEPTH <FTJ <FT .\ 0.00 0 .00 0 .50 0 .50 1 .00 0 .50 1 .50 0 .50 2 .00 0 .50 INCR. VOLUME <CU.-FT.l 0 .00 172 .75 1051 .25 2721 .75 5310.00 PAGE 1OF1 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON TOTAL INCR. TOTAL VOLUME VOLUME VOLUME <CU .-FT.l IAC.-FT.l IAC .-FT.\ 0 .00 0 .00 0 .00 172 .75 0 .00 0 .00 1224.00 0 .02 0 .03 3945.75 0.06 0 .09 9255.75 0.12 0 .21 S PREAD SHEET 2: O UTLET WO RKS DI SCHARGE CO M PUTATIONS PAGE 1OF1 PROJECT : LOCAT ION : CLIENT: POND WATER SURFACE POINT ELEVA Tl< NO . !FEE Tl t 1 278.00 2 278.50 3 279.00 4 2 79.50 5 280.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ORIFICE Ni 1 2 AREA, SF 0 .00 0 .00 INV ERT 0.00 0 .00 Co 0 .00 0 .00 Qo1 CFS Qo2 CFS 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 3 0 .00 0 .00 0 .00 Qo3 CFS 0 .00 0 .00 0 .00 0 .00 0 .00 DATE : ENGINEER: DESIGNER : WEIR NO. 1 LENGTH, I 0.50 IN V ERT El 278.00 Cw 3 .10 Qw1 CFS 0 .00 0 .55 1.55 2 .85 4 .38 06..J ul-OO ROBERTSON CONSUL TING R. ROBERTSON 2 3 POND 0 .00 0 .00 OUTLET 0 .00 0 .00 TOTAL 0 .00 0 .00 DISCH A RC Qw2 CFS Qw3CFS ICFSl 0 .00 0 .00 0.00 0 .00 0 .00 0 .55 0 .00 0 .00 1.55 0 .00 0 .00 2.85 0 .00 0 .00 4 .38 SPREADSHEET 3: 2*S/delta T +OUTFLOW COMPUTATIONS PROJECT : LOCATION : CLIENT : EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. ENTER COMPUTATION TIME INTERVAL IN MINUTE~ 2 .00 STORAGE STORAGE OUTFLOW POINT ELEVA Tl< DEPTH "S" "S" "O" NO. (FEET) !FT .l !CU .-FT .l !AC.-FT .\ ICFS\ 1 278.00 0 .00 0 .00 0 .00 0 .00 2 278.50 0 .50 172.75 0 .00 0.55 3 279.00 1.00 1224.00 0 .03 1.55 4 279.50 1.50 3945.75 0 .09 2 .85 5 280.00 2 .00 9255.75 0 .21 4.38 DATE : 06-Jul-OO ENGINEER ROBERTSON CONSULTING DESIGNERR. ROBERTSON LOG LOG 2Sldt+O "O" 2S/dt+O ICFS\ ICFS\ ICFS\ 0 .00 0 .00 0 .00 3 .43 -0 .26 0 .53 21 .95 0 .19 1.34 68 .61 0 .45 1.84 158.65 0 .64 2 .20 SPREADSHEET 4a: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCAT ION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0 .74 4 1.48 6 2.22 8 2.96 10 3 .70 12 2.96 14 2.22 16 1.48 18 0 .74 20 0 .01 22 0 .01 EAGLE AVE. CH URCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 0 .74 2.22 3 .70 5 .18 6.66 6.66 5.18 3 .70 2.22 0.75 0.02 2YEAR STORM DATE : ENGINEER: DESIGNER : "l"n-1 + "l"n + (2S/dT-O)n (2S/d T-O)n (CFS) (CFS) 0 .00 0 .00 0 .00 0 .74 -1 .13 1.09 -0 .95 2.75 0 .23 5.41 2.46 9.12 5.80 12.46 8.90 14.08 10.41 14.11 10.44 12 .66 9 .08 9 .83 6.45 6.47 06-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 0 .93 1.02 1.26 1.47 1.66 1.78 1.83 1.84 1.79 1.69 1.53 SPREADSHEET 4b : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJ ECT : LOCA TI ON : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0.90 4 1.80 6 2.70 8 3.60 10 4.50 12 3.60 14 2.70 16 1.80 18 0 .90 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 EAGLE AVE. CHURCH COLLEGE STATIO N, TX STYLECRAFT BU ILDE RS INC. "l"n-1 + "l"n (CFS) 0 .00 0 .90 2 .70 4 .50 6 .30 8.10 8 .10 6 .30 4.50 2.70 0 .91 0 .02 0 .02 0 .02 0 .02 0 .02 5 YEARSTORM DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0 .00 0.00 0 .90 -1 .05 1.65 -0 .59 3.91 1.17 7 .47 4.30 12 .40 8.84 16.94 13 .11 19.41 15.46 19.96 15 .99 18.69 14 .77 15.68 11 .92 11 .94 8.41 8.43 5 .17 5.19 2.27 2.29 -0 .13 -0 .11 07-Jul-OO ROBERTSON CONSUL TING R. ROBE RTSON OUTFLOW "O" (CFS) 0 .00 0 .98 1.12 1.37 1.59 1.78 1.91 1.97 1.99 1.96 1.88 1.77 1.63 1.46 1.21 ERR SPREADSHEET 4c: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.02 4 2.04 6 3.06 8 4.08 10 5.10 12 4 .08 14 3 .06 16 2 .04 18 1.0 2 20 0.0 1 22 0 .01 24 0.01 26 0 .01 28 0 .0 1 10 YEAR STORM EAG LE AVE. CHURCH CO LLEGE STATION, TX STYLECRAFT BUILDERS IN C. "l"n-1 + "l"n (CFS) 0 .00 1.02 3 .06 5 .10 7 .14 9 .18 9 .18 7 .14 5 .10 3 .06 1.03 0 .0 2 0 .0 2 0 .0 2 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .99 -0 .26 2 .05 6 .00 11 .63 17.02 20.25 21 .40 20.54 17.75 14 .10 10.63 7 .35 DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2 S/dT-O)n (CFS) 0 .00 1.02 2.07 4.84 9 .19 15 .18 20 .8 1 24 .16 25 .35 24 .46 21 .57 17 .77 14 .12 10.65 7.37 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OU TFLOW "O" (CFS ) 0 .00 1.00 1.17 1.39 1.60 1.77 1.90 1.96 1.98 1.96 1.91 1.83 1.75 1.65 1.52 SPREADSHEET 4d: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO . TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 1.16 4 2.32 6 3 .48 8 4.64 10 5 .80 12 4.64 14 3 .48 16 2.32 16 1.16 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 25 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.16 3 .48 5.80 8.12 10.44 10.44 8 .12 5.80 3.48 1.17 0 .02 0 .02 0 .02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .91 0.09 2.88 7.54 14 .10 20 .37 24 .18 25 .61 24 .76 21 .71 17 .68 13.83 10 .20 6.81 DATE : ENGINEER: DESIGNER : "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.16 2.57 5.89 11 .00 17.98 24 .54 28 .49 29 .98 29 .09 25 .93 21 .73 17.70 13.85 10.22 6 .83 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 1.03 1.24 1.50 1.73 1.94 2.08 2.16 2.18 2.17 2.11 2.03 1.93 1.83 1.70 1.55 SPREADSHEET 4e : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT : LOCATION : CLIENT: INFLOI/ HYDRO . TI ME INFLOW "T"n "l"n (M IN ) (CFS) 0 0 .00 2 1.32 4 2.64 6 3 .96 8 5.28 10 6.60 12 5.28 14 3 .96 16 2.64 18 1.32 20 0.01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 50 YEAR STORM EAGLE AVE. CHURCH COL LEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.32 3.96 6.60 9.24 11 .88 11 .88 9.24 6 .60 3 .96 1.33 0.02 0.02 0.02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0 .81 0 .55 4.01 9 .63 17.47 25 .00 29.75 31 .79 31 .20 28 .09 23 .81 19.69 15.75 12 .00 DATE : ENGINEER : DESIGNER : "l"n-1 + "l"n + (2S/dT-O)n (CFS ) 0 .00 1.32 3 .15 7 .15 13 .25 21 .51 29 .35 34 .24 36 .35 35 .75 32 .53 28.11 23 .83 19.71 15.77 12 .02 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OU TFLOW ·o· (CFS) 0 .00 1.07 1.30 1.57 1.81 2.02 2.17 2.25 2.28 2.27 2.22 2.15 2.07 1.98 1.88 1.77 SPREADSHEET 4f: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT: LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.38 4 2 .76 6 4.14 8 5.48 10 6.90 12 5.48 14 4 .14 16 2.76 18 1.38 20 0 .0 1 22 0.0 1 24 0.01 26 0.01 28 0.01 30 0.01 -100 YEAR STORM EAGLE AVE . CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. "l"n -1 + "l"n (CFS) 0 .00 1.38 4.14 6.90 9.62 12 .38 12 .38 9 .62 6 .90 4.14 1.39 0 .02 0 .02 0.02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -0.77 0 .72 4 .44 10.39 18.67 26.66 31 .72 33.99 33 .52 30 .40 26 .04 21 .83 17.79 13.94 DATE: ENGINEER: DESIGNER: ·i·n-1 + ·1·n + (2S/dT-O)n (CFS) 0 .00 1.38 3 .37 7 .62 14.06 22 .77 31 .05 36.28 38 .62 38 .13 34 .91 30 .42 26.06 21 .85 17.81 13.96 07-Jul-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 1.08 1.32 1.59 1.83 2 .05 2.20 2 .28 2 .31 2.31 2.26 2 .19 2.11 2.03 1.94 1.83 '---. STAFF REVIEW COMMENTS No. 2 Project: EAGLE AVENUE CHURCH OF CHRIST (CUP)-CONDITIONAL USE PERMIT (0-114) PLANNING 1. Reviewed by: *PLANNER NOT ASSIGNED* Date: June 4 , 1999 ENGINEERING 1. Items 19-24 of Staff Review Comments 1 have been addressed satisfactorily. Before a development permit can be issued an erosion co_!:!.trol plan must he s11hmitted and a roved. Reviewed by: Ted Ma~ Date : July 17, 2000 ELECTRICAL 1. Reviewed by: Jennifer Reeves Date: 07/17/00 Staff Review Comments Page 1 of 1 NOTE: Any changes made to the plans , that have not been requested by the City of College Station , must be explained in your next transmittal letter and "bubbled" on your plans . Any additional changes on these plans that have not been pointed out to the City , will constitute a completely new review . St aff Review Co mments Page 2 of 1 FOR OFFICE USE ONLY CASE NO. 00 -lllf DATE SUBMITTED bK .;2.:~ 1'P-6a.~Avt-f.l\..u.rdA._ (!J-6~ CONDITIONAL USE PERMIT APPLICATION 'lltt co (CHURCH) II :30f4V" Minimum Requirements -t.L. $150 .00 application fee. _J..L Ten (I 0) copies of site plan which includes requirements for site plan proposals as listed on attached sheet . This , ,.Aite plan will be reviewed by Staff, after which ten ( 10) copies of revised site plan will be required . __ V_ I Detailed explanation of proposed use including hours of operation, anticipated traffic, number of employees, numb er of students , children, ages of children, church members, etc ., as applicable . r1,/t1 If si gn is planned for project, site plan should include sign elevation and details . If sign details are not includ ed on plans submitted with this application, any future sign may have to be considered as a separate conditional use permit and all of the above requirements must be repeated. 0 Use Only 0 Site Plan Only )(' Site Plan and Use )~ NAME OF PROJECT &c,j/e ftve.n ve Cb,1ccl1 o £) Ch!"/Si tl/S- ADDRESsf tf3 ( tJ /3'n!j {e A-ve.nv C LEGAL DESCRIPTION l-of -I i Bue-ii l ~pc i43 hr(>,1 k 5,,bd/0,ls,211 APPLICANT ~rimary Contact for the Project): 1 I Name (}c ?hr1 fZhode&J )f,;fc C r--t. A B ~,t fa e,,.-S Street Address lf (( J 5 T ti IA y & 5 City (G // c9 e Si-1 f:'JJ1 State TX ZipCode ·77~LfS: E-MailAdo/ess jrhocles 6/sfJr:11 -..f~_,i·~).:i,->,t v,, PhoneNumber Gczo-iJ...:;,d. exfdoFaxNumber lt qC-o t./3~ ~~:JJ~. PROPERTY OWNER'S INFORMATION: Name $v11?Jc' ct 5 A-f?p Ltceza .f ' Street Address ----------------City ------------- State Zip Code ______ E-Mail Address ------------ Phone Number Fax Number --------------------------- ARCHITECT OR ENGINEER'S INFORMATION : Name )o(' c.Ph;/;o s I Street Address 7 (;, i Y. f,-.;1ri (I'S C ity Co /l.c'j < )/-;;fj On State 'T '/, Zip Code 7 7 8 6 8 E-Mail Address -----------· Phone Number t::;f;Cz --·5-~ 15 Fax Number ------------·---- OTHER CONT ACTS (Please specify type of conta_£t, i.e . project manager, potential buyer, local contact , etc .) Name f2 c b~:bo ,,.., (o n S"' f f,'nj /::h.._1,:lt1 'i r:,-) Street Address J oo~; \vr.)'-cl /r (' e(c 1 C ity c· er //..;>c, t S~f! cJ ./] 7 State Tl Zip Code 7 7 b1 Y c5 E-Mail Addres Phone Number (o c7 3 -· l"lf t) lf Fax Number----------------·-- CUP -CHURCH I of2 CUP ACHUR 04/14 /99 PROPOSEDUSEOFPROPER1Y __ ->-<---'-'-"'-'-'--'~---------------~~~­ CURRENTZONINGOFPROPER1Y __ ~-.1..--------------~~~-- Total Acreage ~ 1 0 C, cl Building Sq . Ft. d.ooo Floodplain Acreage ______ _ v ARIANCE(S) REQUESTED AND REASON(S) ~11:..._:_iLt>L!n....=::e=------------------- NUMBER OF PARKING SPACES REQUIRED _q-'-· . ....;;..Q __ NUMBER OF PARKING SPACES PROVIDED 4 t ----- APPLICATION WILL NOT BE CONSIDERED COMPLETE WITHOUT THE FOLLOWING INFORMATION ADDRESSED: 1. Approximate the distance to the nearest night clubs, restaurants, and retail commercial establishments . 2 . Discuss the possible necessity for screening (fence or vegetation) between the subject site and adjoining residential properties. ll \, i l/ ' : 3 . List all incidental uses along with hours of operation (including but not limited to school, day care, sports activities, etc .) and 7 0 CU.t ~ 1/Jn r1 I c/1 v cch I verify that all of the information contained in this application is true and correct . CUP-CHURCH CUPACHUR 04114199 Dai6 I 2 of2 SUPPLEMENTAL DEVELOPMENT PERMIT INFORMATION Application is hereby made,for the following development specific waterway alterations: ACKNOWLEDGMENTS: I, 'J Dhn .[l.J1cJ.t...) fOr S~yU ,,....QI.ft . design engineer/owner, hereby acknowledge or affirm that: The information and conclusions contained in the above plans and supporting documents comply with the current requirements of the City of College Station, Texas City Code, Chapter 13 and its associated Drainage Policy and Design Standards. As a condition t~:;:;al of this permit application, I agree to construct the improvements proposed in this application according to these enlT~ req~ents of Chapter 13 of the College Station · e. ~ (tv: ,,' ,CJ-- Property \)wner(s) CERTIFICATIONS: (for proposed alterations within designated floOd hazard areas.) A. I, certify that any nonresidential structure on or proposed to be on this site as part of this application is designated to prevent damage to the structure or its contents as a result of flooding from the 100 year storm. Engineer Date B. I, certify that the finished floor elevation of the lowest floor, including any basement, of any residential structure, proposed as part of this application is at or above the base flood elevation established in the 'latest Federal Insurance Administration Flood Hazard Study and maps, as amended. Engineer Date C. I, certify that the alterations or development covered by this permit shall not diminish the flood~ng capacity of the waterway adjoining or crossing this permitted site and that such alterations or development are consistent with requirements of the City of College Station City Code, Chapter 13 concerning encroachments of flood ways and of flood way fringes . I : Engineer Date D . I, , do certify that the proposed alterations do not raise the level of the 100 year flood above elevation established in the latest Federal Insurance Administration Flood Hazard Study. Engineer D ate Conditions or comments as part of approval:------------------------------ In accordance with Chapter 13 of t11e Code of Ordinances of t11e City of College Station, measures shall be taken to insure tlrnt debris from construction, erosion, and sedimentation shall not be deposited in city streets, or existing drainage facilities. i hereby grant t11is permit for development. All devel op ment shall be in accordance witJ1 the plans and specifications submitted to and approved by the City Engineer for t11e above named project. All of tJ1e applicable codes and ordinances of th e City of College Station shall apply. SITE PlAN APPLICATION SITEAPP.DOC 03125199 3 of3 FOR OFFICE USE ONLY CASE NO. 00 -lll.f ~)!·. DATE SUBMITTED / c.ocuca STAUON CONDITIONAL USE PERMIT APPLICATION (CHURCH) Minimum Requirements ---LL'-$150 .00 application fee . . _J..L Ten (I 0) copies of site plan which includes requirements for site plan proposals as listed on attached sheet. This , fiite plan will be reviewed by Staff, after which ten (10) copies of revised site plan will be required . _V_ I Detailed explanation of proposed use including hours of operation, anticipated traffic, number of employees, /l /.,, number of students , children, ages of children, church members, etc ., as applicable . ~ If sign is planned for proj ect, site plan should include sign elevation and details . If s ign details are not included on plans submitted with this application, any future sign may have to be considered as a separate conditional use permit and all of the above requirements must be repeated. 0 Use Only 0 Site Plan Only }j( Site Plan and Use NAME OF PROJECT &Q!J/e 11-ven v e Cih1cc h o £ Che/sf ADDRESsf ( $3 (lJ £'n 3 /e A-ve-nv<:. LE GAL DESCRIPTION !.-of -I i B /I C-II 1 5" pc i 4 y b r c> c1 k ~11bd /&/s ,211 APPLICANT fi.rimary Contact for the Project): 1 I Name <..}oha e.ho deS) >fyf e. C r;. A B vtiaer s Street Address lf((;), 5 T ti"'-y C. S City Cc-)/,9 e )/,J-/(fJ/l State TX Zip Code 7 7~ 4-S: E-Mail Address j i h od e S @sfvlecr;,.f..B .,;"t)a ,-r., lv, Phone Number G CZ 0 -iJ.. J_(). exf~o Fax Number ______________ _ PROPERTY OWNER'S INFORMATION: Name $0 0r t:'t 5 A-,Pf? ltc0a :f Street Address ~---------------City ------------- E-Mail Address ------------State ----Zip Code ____ _ Phone Number Fax Number ~---------~---------------- ARCIDTECT OR ENGINEE R 'S INFORMATION: Name :Ioe C, Phi/; o S I StreetAddress 7 C.ilf fr-~11'1(/S City Co/l.cj< 5'.hi,-f/on State T i Zip Code 7 7 8 6 8 E-Mail Address __________ _ Phone Number t;;5Cz -·~ 15 Fax Number ----------------- 0 TIIE R CONT ,\CT (Pl ease sp ecify type of conta.st, i.e. project manage r, pote1.!.i al buye r, local contact, etc.) Name 'f2obv1 -ri (o n sd ,";., bh · .: -c e1 Street Address Joo 8; lvocd C:J t: e{c City c· er//..,,~, t S.hi_f ! c!rz J State Ti. Zip Code 77 fJ Cf S' E-Mail Address ----------- Phone N u mber b tJ 3 _, 5" lf ')If Fax Number ~-------------~-- CUP . CHURCH l of 2 CUPACHUR 04/14199 DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION June 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 CERTIFICATION I hereby certify that this report and accompanying drainage plan for the drainage design of Proposed Eagle A venue Church was prepared by me in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof Registered Professional Engineer State of Texas No. 56375 Introduction The proposed project is located on Eagle Avenue immediately west of State Highway 6 in the Springbrook Subdivision . The project consists of a new building and site improvements for a 2 .099 acre tract. The site was originally part of a 5.751 acre tract which currently is occupied by Stylecraft Builders Inc . The lot for this project was replatted and separated from the original tract. Figure 1 shows the original drainage map for the Stylecraft project, taken from the drainage report prepared by McClure Engineering Inc . No portion of the project lies within the current boundaries of the regulatory 100-year Floodplain for the City of College Station. The project lies within the Lick Creek drainage basin. Existing Drainage Patterns The tract and relevant adjacent land areas that contribute runoff to it are undeveloped at this time . Existing land cover consists of natural grasslands . The site receives a substantial amount of off-site flows from areas to the north . The on-site and off-site stormwater flows are discharged to the east into a drainage channel in the adjacent drainage easement on the east side of the property. Proposed Drainage Patterns The proposed drainage patterns and improvements are depicted in Figure 2 . Detailed calculations for the improvements are contained in Appendices A - B . The plans for this project depict the detailed construction necessary to accomplish the proposed drainage improvements and are made a part of this report . The north area identified as lB will continue to discharge into the channel in the drainage easement on the east side of the property . No detention is needed for this site on the north area, as no new construction on this site will occur. The offsite areas to the north of this tract are assumed to contribute no additional runoff to this site when they are developed . The south area identified as lA represents the developed portion of the tract . Detention is provided for this portion of the site utilizing a portion of the proposed parking area on the southeast comer of the site . The curb will be built higher at the outlet end of the detention area and have a 6" width curb opening discharging into a 2 foot width concrete outlet weir. The detention basin will collect all waters from the developed area of this site and will discharge directly into the existing channel and drainage easement . The detention area is designed to limit the discharge for the 2-year to 100-year storms from the proposed project to less than the discharge that existed prior to construction. Emergency overflow of the detention area will occur over the curb into the channel. The detention basin will pond water to a maximum elevation of 279 .25 feet during the 100-year storm. A combined summary of pre-and post-development peak discharges for the project is provided in Table 1. 2-year 5-year IO-year 25-year 50-year 100-year storm storm storm storm storm storm Existing 1.56 1.89 2.12 2.43 2.74 2.86 Develop 3 .63 4.41 4 .95 5.65 6 .3 9 6 .67 Detained 1.81 1.97 2 .07 2 .17 2.26 2.30 Table 1. Peak Project Discharges (cfs) Conclusions Although the calculations provided are numerically correct in the application of the principles of hydraulics and hydrology, the actual numbers are below the limits of what is considered the accuracy of the underlying methodology. Calculating discharges to the .01 cfs , .1 cfs, or even 1 cfs , is false accuracy when using any hydrologic method . This site originally discharged about 2-3 cfs over the range of design storms considered. If no detention is provided it will only discharge 4 -7 cfs from the same storms when ultimately developed . The detention provided will reduce that discharge to 2 -3 cfs. Within the accuracy of existing hydrologic methods, these numbers are the same . That having been said, the proposed project meets the drainage requirements of the City of College Station. No higher peak stormwater flows will be directed to Eagle Avenue, the existing drainage easement and channel, or the receiving storm sewer. APPENDIX A DISCHARGE CALCULATIONS SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION: CLIENT: DRAINAGI COMP. BASIN RUNOFF ID COEFF . 1A 0.30 18 0.30 TOTAL 0.30 1A 0.70 18 0.30 TOTAL 0.32 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . BASIN NATURAL WOODLANDS AREA AREA SLOPE RUNOFF <ACRES) (ACRES) (FT/FT) COEFF. EXIST. SITE 0.82 0.00 0.00 0.00 18.00 0.00 0.00 0.00 18.82 0.00 0.00 0 .00 PROP. SITE 0.82 0.00 0.00 0.00 18 .00 0.00 0.00 0 .00 18.82 0.00 0.00 0 .00 NATURAL GRASSLANDS AREA SLOPE RUNOFF (ACRES) <FT/FT) COEFF . 0.82 0 .01 0 .30 18 .00 0.01 0.30 18.82 0.02 0.30 0.00 0.00 0.00 18 .00 0.01 0.30 18.00 0.02 0 .30 ~ DATE: ENGINEER: DESIGNER: LANDSCAPED AREAS AREA SLOPE RUNOFF (ACRES) <FT/Fn COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.30 0.01 0.35 0.00 0.00 0.00 0.30 0.01 0.40 PAGE 1-L OF 1 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON IMPERVIOUS AREA SLOPE RUNOFF <ACRESl <FT/Fn COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.52 0.01 0.90 0.00 0.00 0.00 0.52 0.01 0.90 SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION: CLIENT: EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. LOW DENSITY RESIDENT! MED. DENSITY RESIDEN" AREA SLOPE RUNOFF AREA SLOPE RUNOFF CACRESl CFT/Fn COEFF. <ACRES) <FTIFn COEFF. 0 .00 0.00 0.00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 HIGH DENSITY RESIDEN" AREA SLOPE RUNOFF <ACRES) (FT/FT) COEFF. 0.00 0.00 0 .00 0.00 0 .00 0.00 0.00 0 .00 0 .00 0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0 .00 ' DATE: ENGINEER: DESIGNER: BUSINESS I COMMERCIA AREA SLOPE RUNOFF (ACRES) CFTIFn COEFF. 0 .00 0.00 0.00 0.00 0.00 0.00 0 .00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 PAGE 1-R OF 1 07-Jun-OO 0.00 0.00 AREA <ACRES) 0.00 0.00 0.00 0.00 0.00 0.00 INDUSTRIAL SLOPE RUNOFF CFT/Fn COEFF. 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0 .00 0.00 0.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION : CLIENT: DRAINAGI DESIGN BASIN "Tc" ID (MIN) EXIST. 1A 10 .00 1B 35.00 TOTAL 35.00 PROP . 1A 10.00 1B 35.00 TOTAL 35 .00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. CALC. NATURAL WOODLANDS "Tc" LENGTH SLOPE VELOCIT (MIN) (FEEn (FT/FT} (FT/SEC) SITE 10.00 0.00 35.00 0.00 35.00 0.00 SITE 1.94 0.00 35.00 0.00 35 .00 0.00 I DATE: ENGINEER: DESIGNER: NATURAL GRASSLANDS LANDSCAPED AREAS LENGTH SLOPE VELOCIT LENGTH SLOPE VELOCIT (FE En (FT/FT) (FT/SEC) (FE En (FT/Fn (FT/SEC) 300.00 0.01 0.50 0.00 300 .00 0.01 0.50 0.00 300.00 0.01 0.50 0.00 0.00 100.00 0.01 2.00 300.00 0.01 0.50 0.00 300.00 0.01 0.50 0.00 PAGE 1-L OF 1 07-Jun-OO 0.00 0.00 LENGTH (FE En 0.00 0.00 0.00 200.00 0.00 0.00 PAVEMENT SLOPE (FT/FTI 0.01 VELOCITY CFT/SEC) 3.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT : PIPE LENGTH SLOPE (FEED (FT/FT) 0.00 0.00 0.00 0 .00 0.00 0 .00 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC . OPEN CHANNEL VELOCITY LENGTH SLOPE VELOCITY (FT/SEC) (FEED (FT/FD (FT/SEC) 0.00 0.00 0.00 0.00 0.00 0 .00 ' NATURAL SWALE LENGTH SLOPE VELOCITY (FEET) (FT/FD (FT/SEC) 0.00 1500.00 0 .01 1.00 1500 .00 0.01 1.00 0.00 1500.00 0.01 1.00 1500 .00 0 .01 1.00 DATE: ENGINEER: DESIGNER: SPREADSHEET 3: BASIN RAINFALL INTENSITY AND DISCHARGE COMPUTATIONS SHEET 1OF1 PROJECT : LOCATION: CLIENT: DRAINAG COMP. BASIN RUNOF ID COEFF . 1A 0.30 19 0 .30 TOTAL 0.30 1A 0 .70 18 0 .30 TOTAL 0 .32 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . BASIN TIMEOI 2YEARSTORM AREA CONC . "I" "Q" (ACRES (MIN) (IN/HR) (CFS) EXIST. SITE 0.82 10.00 6 .33 1.56 18 .00 35 .00 3 .14 16 .93 18.82 35.00 3.14 17.70 PROP. SITE 0.82 10.00 6 .33 3 .63 18.00 35.00 3 .14 16 .93 18 .82 35 .00 3.14 18.78 5YEARSTORM "I" "Q" (IN/HR) (CFS) 7 .69 1.89 3.93 21 .23 3.93 22 .20 7 .69 4 .41 3 .93 21.23 3.93 23 .54 10YEAR STOR "I" "Q" (IN/HR) (CFS) 8 .63 2 .12 4 .50 24 .28 4 .50 25 .39 8 .63 4 .95 4 .50 24 .28 4 .50 26 .93 DATE: ENGINEER : DESIGNER : 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON 25YEAR STOR 50 YEAR STORM 100 YEAR STOF "I" "Q" "r' "Q" "I" "Q" CIN/HR) (CFS) (IN/HR) (CFS) CIN/HR) (CFS) 9.86 2 .43 11 .15 2.74 11.64 2.86 5.18 27 .95 5 .90 31 .84 6.16 33 .28 5 .18 29.22 5.90 33 .29 6.16 34 .80 9.86 5.65 11 .15 6 .39 11 .64 6 .67 5 .18 27 .95 5 .90 31 .84 6 .16 33 .28 5 .18 30 .99 5.90 35 .30 6 .16 36 .91 APPENDIXB DETENTION CALCULATIONS SPREADSHEET 1: POND STORAGE COMPUTATIONS PROJECT : LOCATION : CLIENT: POINT ELEVATIC NO . lFEETI 1 278.00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE . CHURCH COLI.EGE STATION, TX STYLECRAFT BUILDERS INC . AVERAGE POND ARE.I POND ARE POND ARE (SQ .-FT.) (ACRES) (SQ .-FT .) 0 .00 0 .00 0 .00 691 .00 0 .02 345.50 3514.00 0 .08 2102.50 7373.00 0 .17 5443.50 13867.00 0 .32 10620.00 DATE : ENGINEER : DESIGNER : INCR. DEPTH DEPTH (FT.) (FT.) 0 .00 0 .00 0 .50 0.50 1.00 0 .50 1.50 0 .50 2 .00 0.50 INCR . VOLUME (CU.-FT.) 0.00 1n.15 105125 2721 .75 5310.00 PAGE 1OF1 07..Jun-OO ROBERTSON CONSUL TING R. ROBERTSON TOTAL INCR. TOTAL VOLUME VOLUME VOLUME (CU .-FT .) (AC .-FT.) (AC . ..f'T .) 0.00 0.00 0.00 1n.15 0 .00 0 .00 1224.00 0 .02 0 .03 3945.75 0 .06 0.09 9255.75 0 .12 021 SPREADSHEET 2: OUTLET WORKS DISCHARGE COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: POND WATER SURFACE POINT ELEVA TIC NO. CFEETl 1 278.00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. PRIFICEN< 1 2 AREA, SF 0.00 0.00 INVERT 0.00 0.00 Co 0.00 0.00 Qo1 CFS Qo2 CFS 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3 0.00 0.00 0.00 Qo3CFS 0.00 0.00 0.00 0.00 0.00 DATE: ENGINEER: DESIGNER: WEIR NO. 1 ~ENGTH, f 0.50 INVERT El 278.00 Cw 3.10 Qw1 CFS 0.00 0.55 1.55 2.85 4.38 07..Jun-OO ROBERTSON CONSUL TING R. ROBERTSON 2 3 POND 0.00 0.00 OUTLET 0.00 0.00 TOTAL 0.00 0.00 DISCHARC Qw2 CFS Qw3CFS (CFS\ 0.00 0.00 0.00 0.00 0.00 0.55 0.00 0.00 1.55 0.00 0.00 2.85 0.00 0.00 4.38 SPREADSHEET 3: 2*S/delta T + OUTFLOW COMPUTATIONS PROJECT : LOCATION : CLIENT : EAGLE AVE. CHURCH COLLEGE ST A TION, TX STYLECRAFT BUILDERS INC. ENTER COMPUTATION TIME INTERVAL IN MINUTEE 2 .00 STORAGE STORAGE !OUTFLOW POINT ELEVA Tl< DEPTH "S" ·s · ·o· NO. IFEETl IFT.l ICU.-FT .l IAC.-FT .l CCFSl 1 278.00 0 .00 0 .00 0 .00 0.00 2 278 .50 0 .50 172.75 0.00 0.55 3 279 .00 1.00 1224.00 0 .03 1.55 4 279.50 1.50 3945.75 0 .09 2.85 5 280.00 2.00 9255.75 0 .21 4.38 DATE : 07.Jun-OO ENGINEERROBERTSON CONSULTING DESIGNERR. ROBERTSON LOG LOG 25/dt+O ·o· 25/dt+O ICFSl ICFSl ICFSl 0 .00 0 .00 0.00 3 .43 -0 .26 0 .53 21 .95 0.19 1.34 68.61 0 .45 1.84 158.65 0 .64 2.20 SPREADSHEET 4a: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 0.72 4 1.44 6 2.16 8 2.88 10 3.60 12 2.88 14 2.16 16 1.44 18 0.72 20 0.01 22 0.01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0.00 0.72 2.16 3.60 5.04 6.48 6.48 5.04 3.60 2.16 0.73 0.02 2YEARSTORM DATE: ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0.00 0.00 0.00 0.72 -1.13 1.03 -0.99 2.61 0.12 5.16 2.25 8.73 5.44 11.92 8.39 13.43 9.80 13.40 9.77 11.93 8.40 9.13 5.81 5.83 07-Jun..QO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 0.93 1.01 1.25 1.46 1.64 1.77 1.81 1.81 1.77 1.66 1.50 SPREADSHEET 4b: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLO\I HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0 .88 4 1.76 6 2.64 8 3 .52 10 4.40 12 3.52 14 2.64 16 1.76 18 0.88 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 EAGLE AVE . CHU~ COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ·1·n -1 + "l"n (CFS) 0.00 0 .88 2.64 4.40 6 .16 7.92 7 .92 6 .16 4.40 2.64 0 .89 0 .02 0 .02 0.02 0.02 0.02 5 YEARSTORM DATE : ENGINEER: DESIGNER: "l"n-1 + •1•n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0.00 0 .00 0 .88 -1.06 1.58 -0.64 3.76 1.05 7 .21 4.06 11 .98 8 .45 16.37 12 .57 18.73 14.81 19.21 15.27 17.91 14.04 14.93 11 .21 11 .23 7 .74 7 .76 4.56 4.58 1.75 1.77 -0 .51 -0 .49 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 0.97 1.11 1.35 1.57 1.77 1.90 1.96 1.97 1.94 1.86 1.74 1.60 1.42 1.14 ERR SPREADSHEET 4c: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION : CLIENT: INFLO\I HYDRO. TIME INFLOW "T"n •1·n (MIN) (CFS) 0 0 .00 2 1.00 4 2.00 6 3 .00 8 4.00 10 5 .00 12 4 .00 14 3 .00 16 2.00 18 1.00 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0.01 1 O YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. "l"n-1 + ·1·n (CFS) 0 .00 1.00 3 .00 5 .00 7 .00 9 .00 9 .00 7.00 5 .00 3 .00 1.01 0 .02 0 .02 0 .02 0 .02 (2S/dT..O)n (CFS) 0 .00 0.00 -1 .00 -0 .34 1.81 5 .51 10.82 15.85 18.75 19.62 18.53 15.58 11 .85 8 .34 5.10 DATE : ENGINEER : DESIGNER: "l"n-1 + "l"n + (2S/dT..O)n (CFS) 0 .00 1.00 2.00 4.66 8.81 14 .51 19.82 22 .85 23.75 22 .62 19.54 15.60 11 .87 8 .36 5.12 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 1.00 1.17 1.42 1.65 1.85 1.98 2.05 2.07 2.04 1.98 1.88 1.76 1.63 1.45 SPREADSHEET 4d: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT: LOCATION : CLIENT: INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.14 4 2 .28 6 3 .42 8 4.56 10 5 .70 12 4 .56 14 3 .42 16 2.28 18 1.14 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 25 YEAR STORM EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.14 3 .42 5 .70 7.98 10.26 10.26 7.98 5 .70 3.42 1.15 0.02 0.02 0.02 0.02 0.02 (25/dT-O)n (CFS) 0.00 0 .00 -0.92 0 .03 2.75 7.28 13.68 19.80 23.49 24.85 23.97 20.93 16.93 13.12 9 .53 6 .20 DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.14 2.50 5 .73 10.73 17.54 23.94 27.78 29.19 28.27 25.12 20.95 16.95 13.14 9 .55 6 .22 07..Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0.00 1.03 1.23 1.49 1.72 1.93 2.07 2.14 2.17 2.15 2.09 2.01 1.91 1.81 1.68 1.52 SPREADSHEET 4e: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: INFlQ\11 HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 128 4 2.56 6 3.8'4 8 5.12 10 6.40 12 5.12 14 3.84 16 2.56 18 1.28 20 0.01 22 O.o1 24 0.01 26 0.01 28 0.01 30 0.01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ·rn-1 + "l"n CCFSl 0.00 128 3.84 6.40 8.96 11.52 11.52 8.96 6.40 3.84 129 0.02 0.02 0.02 0.02 0.02 50 YEAR STORM DATE: ENGINEER: DESIGNER: (2S/c:IT-O)n (CFS) 0.00 0.00 ..0.84 0.43 3.n 9.10 16.62 23.84 28.34 30.23 29.58 26.47 22.25 18.20 14.33 10.66 "l"n-1 + "l"n + (2S/c:IT-O)n (CFS) 0.00 128 3.00 6.83 12.68 20.62 28.14 32.80 34.74 34.07 30.87 26.49 22.27 18.22 14.35 10.68 07.Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 1.06 129 1.55 1.79 2.00 2.15 2.23 226 2.25 2.20 2.12 2.04 1.95 1.84 1.72 SPREADSHEET 4f: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: INFLOVI HYDRO. TIME INFLOW "T"n •rn (MIN) (CFS) 0 0.00 2 1.36 4 2.72 6 4.08 8 5.40 10 6.80 12 5.40 14 4.08 16 2.72 18 1.36 20 0.01 22 O.Q1 24 O.Q1 26 0.01 28 0.01 30 0.01 -100 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. Tn-1 + •rn (CFS) 0.00 1.36 4.08 6.80 9.48 12.20 1220 9.48 6.80 4.08 1.37 0.02 0.02 0.02 0.02 0.02 DATE: ENGINEER: DESIGNER: (2S/dT-O)n (CFS) 0.00 0.00 -0.79 0.66 429 10.12 18.25 26.07 31.01 3321 32.70 29.58 25.25 21.07 17.07 13.25 ·rn-1 + ·rn + (2S/dT-O)n (CFS) 0.00 1.36 3.29 7.46 13.77 22.32 30.45 35.55 37.81 37.29 34.07 29.60 25.27 21.09 17.09 13.27 07-JwH>O ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o-(CFS) 0.00 1.07 1.31 1.59 1.83 2.04 2.19 2.27 2.30 2.29 2.25 2.18 2.10 2.01 1.92 1.81 DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION June 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 CERTIFICATION I hereby certify that this report and accompanying drainage plan for the drainage design of Proposed Eagle A venue Church was prepared by me in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof Registered Professional Engineer State of Texas No . 56375 Introduction The proposed project is located on Eagle Avenue immediately west of State Highway 6 in the Springbrook Subdivision . The project consists of a new building and site improvements for a 2 .099 acre tract . The site was originally part of a 5.751 acre tract which currently is occupied by Stylecraft Builders Inc . The lot for this project was replatted and separated from the original tract. Figure 1 shows the original drainage map for the Stylecraft project, taken from the drainage report prepared by McClure Engineering Inc . No portion of the project lies within the current boundaries of the regulatory 100-year Floodplain for the City of College Station. The project lies within the Lick Creek drainage basin. Existing Drainage Patterns The tract and relevant adjacent land areas that contribute runoff to it are undeveloped at this time . Existing land cover consists of natural grasslands . The site receives a substantial amount of off-site flows from areas to the north. The on-site and off-site stormwater flows are discharged to the east into a drainage channel in the adjacent drainage easement on the east side of the property. Proposed Drainage Patterns The proposed drainage patterns and improvements are depicted in Figure 2 . Detailed calculations for the improvements are contained in Appendices A-B . The plans for this project depict the detailed construction necessary to accomplish the proposed drainage improvements and are made a part of this report . The north area identified as IB will continue to discharge into the channel in the drainage easement on the east side of the property. No detention is needed for this site on the north area, as no new construction on this site will occur. The offsite areas to the north of this tract are assumed to contribute no additional runoff to this site when they are developed . The south area identified as IA represents the developed portion of the tract. Detention is provided for this portion of the site utilizing a portion of the proposed parking area on the southeast comer of the site . The curb will be built higher at the outlet end of the detention area and have a 6" width curb opening discharging into a 2 foot width concrete outlet weir. The detention basin will collect all waters from the developed area of this site and will discharge directly into the existing channel and drainage easement. The detention area is designed to limit the discharge for the 2-year to 100-year storms from the proposed project to less than the discharge that existed prior to construction . Emergency overflow of the detention area will occur over the curb into the channel. The detention basin will pond water to a maximum elevation of 279.25 feet during the 100-year storm . A combined summary of pre-and post-development peak discharges for the project is provided in Table 1. 2-year 5-year 10-year 25-year 50-year 100-year storm storm storm storm storm storm Existing 1.56 1.89 2 .12 2.43 2 .74 2 .86 Develop 3 .63 4.41 4 .95 5.65 6.39 6.67 Detained 1.81 1.97 2 .07 2 .17 2.26 2 .30 Table 1. Peak Project Discharges (cfs) Conclusions Although the calculations provided are numerically correct in the application of the principles of hydraulics and hydrology, the actual numbers are below the limits of what is considered the accuracy of the underlying methodology . Calculating discharges to the .01 cfs, .1 cfs, or even 1 cfs, is false accuracy when using any hydrologic method . This site originally discharged about 2-3 cfs over the range of design storms considered . If no detention is provided it will only discharge 4 -7 cfs from the same storms when ultimately developed . The detention provided will reduce that discharge to 2 - 3 cfs . Within the accuracy of existing hydrologic methods, these numbers are the same. That having been said, the proposed project meets the drainage requirements of the City of College Station . No higher peak stormwater flows will be directed to Eagle Avenue, the existing drainage easement and channel, or the receiving storm sewer. APPENDIX A DISCHARGE CALCULATIONS SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION: CLIENT: DRAINAGI COMP. BASIN RUNOFF ID COEFF. 1A 0.30 1B 0.30 TOTAL 0.30 1A 0.70 18 0.30 TOTAL 0.32 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. BASIN NATURAL WOODLANDS AREA AREA SLOPE RUNOFF (ACRES) (ACRES) CFT/FT) COEFF. EXIST. SITE 0 .82 0.00 0.00 0.00 18.00 0.00 0.00 0.00 18 .82 0 .00 0 .00 0 .00 PROP. SITE 0 .82 0 .00 0.00 0 .00 18.00 0.00 0.00 0.00 18.82 0.00 0 .00 0.00 NATURAL GRASSLANDS AREA SLOPE RUNOFF (ACRES) CFT/FT) COEFF. 0.82 0.01 0 .30 18 .00 0.01 0.30 18.82 0.02 0.30 0.00 0.00 0.00 18 .00 0 .01 0 .30 18.00 0.02 0.30 DATE: ENGINEER: DESIGNER: LANDSCAPED AREAS AREA SLOPE RUNOFF (ACRES) (FT/FT) COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.30 0.01 0.35 0 .00 0.00 0 .00 0.30 0.01 0.40 PAGE 1-L OF 1 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON IMPERVIOUS AREA SLOPE RUNOFF (ACRES} (FT/FT) COEFF . 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.52 0 .01 0.90 0.00 0.00 0.00 0.52 0.01 0.90 SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION : CLIENT: EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. LOW DENSITY RESIDENT MED. DENSITY RESIDENl AREA SLOPE RUNOFF AREA SLOPE RUNOFF (ACRES) (FT/FTI COEFF. (ACRES) CFTIFTI COEFF. 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0 .00 0.00 0 .00 0.00 0 .00 0.00 0.00 0 .00 0.00 0.00 HIGH DENSITY RESIDENl AREA SLOPE RUNOFF (ACRES) (FT/Fn COEFF. 0 .00 0.00 0.00 0 .00 0.00 0 .00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0 .00 I DATE: ENGINEER : DESIGNER: BUSINESS I COMMERCIA AREA SLOPE RUNOFF (ACRES) CFTIFT) COEFF. 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0.01 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0.01 0.00 PAGE 1-R OF 1 07-Jun-00 0.00 0 .00 AREA (ACRES) 0.00 0 .00 0 .00 0 .00 0 .00 0.00 INDUSTRIAL SLOPE RUNOFF (FT/FT) COEFF. 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0 .00 0 .00 0.00 0.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT: DRAINAG DESIGN BASIN HTc" ID (MIN) EXIST. 1A 10.00 1B 35 .00 TOTAL 35.00 PROP. 1A 10.00 1B 35.00 TOTAL 35 .00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. CALC . NATURAL WOODLANDS "Tc" LENGTH SLOPE VELOCIT (MIN) (FEETI (FT/FT) (FT/SEC) SITE 10.00 0.00 35 .00 0.00 35.00 0.00 SITE 1.94 0.00 35 .00 0 .00 35.00 0.00 DATE : ENGINEER: DESIGNER: NATURAL GRASSLANDS LANDSCAPED AREAS LENGTH SLOPE VELOCIT LENGTH SLOPE · VELOCIT (FEET) (FT/FT) (FT/SEC) <FE En (FT/Fn (FT/SEC) 300.00 0.01 0.50 0.00 300.00 0.01 0.50 0.00 300.00 0.01 0 .50 0.00 0.00 100.00 0.01 2.00 300 .00 0 .01 0.50 0.00 300 .00 0.01 0.50 0.00 PAGE 1-L OF 1 07-Jun-OO 0.00 0.00 LENGTH (FE En 0.00 0.00 0.00 200 .00 0.00 0.00 PAVEMENT SLOPE (FTtFn 0.01 VELOCITY (FT/SEC) 3.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT: PIPE LENGTH SLOPE lFEETI lFT/FTI 0.00 0.00 0.00 0 .00 0.00 0.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . OPEN CHANNEL VELOCITY LENGTH SLOPE VELOCITY <FT/SEC) lFEETI {FT/FT) <FT/SEC) 0.00 0.00 0 .00 0.00 0.00 0.00 I NATURAL SWALE LENGTH SLOPE VELOCITY (FEET) {FT/FTI {FT/SEC) 0.00 1500.00 O.o1 1.00 1500.00 0 .01 1.00 0.00 1500.00 0.01 1.00 1500.00 0 .01 1.00 DATE: ENGINEER: DESIGNER: SPREADSHEET 3: BASIN RAINFALL INTENSITY AND DISCHARGE COMPUTATIONS SHEET 1OF1 PROJECT: LOCATION : CLIENT: DRAINAG COMP . BASIN RUNOFI ID COEFF. 1A 0 .30 1B 0 .30 TOTAL 0.30 1A 0 .70 1B 0.30 TOTAL 0 .32 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . BASIN TIME OF 2YEARSTORM AREA CONC . "'" "Q" <ACRES (MIN) ON/HR) CCFS) EXIST. SITE 0.82 10.00 6 .33 1.56 18 .00 35.00 3 .14 16.93 18 .82 35 .00 3.14 17.70 PROP. SITE 0.82 10.00 6.33 3.63 18 .00 35 .00 3.14 16.93 18 .62 35 .00 3.14 18.78 5YEARSTORM 10 YEAR STORI 11111 "Q" "I" "Q" ON/HR) (CFS) ON/HR) (CFS) 7.69 1.89 8.63 2 .12 3 .93 21 .23 4 .50 24 .28 3 .93 22 .20 4 .50 25.39 7 .69 4 .41 8.63 4 .95 3 .93 21 .23 4 .50 24.28 3 .93 23.54 4 .50 26.93 DATE: ENGINEER : DESIGNER : 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON 25YEAR STOR 50 YEAR STORM 100 YEAR STOF "I" "Q" "r' "Q" "l't "Q" (IN/HR) (CFS) (IN/HR) (CFS) ON/HR) (CFS) 9 .86 2.43 11 .15 2 .74 11 .64 2.86 5 .18 27 .95 5 .90 31 .84 6.16 33.28 5 .18 29.22 5.90 33 .29 6 .16 34 .80 9 .86 5 .65 11.15 6 .39 11 .64 6.67 5 .18 27 .95 5 .90 31 .84 6 .16 33 .28 5.16 30.99 5.90 35.30 6 .16 36 .91 APPENDIXB DETENTION CALCULATIONS SPREADSHEET 1: POND STORAGE COMPUTATIONS PROJECT : LOCATION : CLIENT: POINT ELEVA TI< NO . <FEETI 1 278.00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . AVERAGE PONDAREJ POND ARE POND ARE <SQ .-FT .l <ACRES\ <SQ . ..fT .l 0 .00 0.00 0 .00 691 .00 0.02 345.50 3514.00 0.08 2102 .50 7373.00 0 .17 5443.50 13867.00 0 .32 10620.00 DATE : ENGINEER : DESIGNER : INCR. DEPTH DEPTH lFT.l <FT .l 0.00 0 .00 0 .50 0 .50 1.00 0 .50 1.50 0 .50 2 .00 0 .50 INCR. VOLUME <CU .-FT.l 0 .00 172.75 105125 2721.75 5310.00 PAGE 1OF1 07-Jun--00 ROBERTSON CONSUL TING R. ROBERTSON TOTAL INCR. TOTAL VOLUME VOLUME VOLUME lCU . ..fT.l <AC .·FT.l <AC . ..fT.l 0.00 0.00 0 .00 172.75 0.00 0 .00 1224.00 0 .02 0.03 3945.75 0.06 0.09 9255.75 0.12 021 SPREADSHEET 2: OUTLET WORKS DISCHARGE COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT: POND WATER SURFACE POINT ELEVA Tl< NO. IFEET\ 1 278.00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. !ORIFICE NC 1 2 AREA, SF 0 .00 0.00 INVERT 0 .00 0 .00 Co 0 .00 0 .00 Oo1 CFS Qo2 CFS 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 3 0 .00 0.00 0 .00 Qo3CFS 0 .00 0 .00 0 .00 0 .00 0 .00 DATE: ENGINEER: DESIGNER: WEIR NO. 1 11..ENGTH , F 0 .50 INVERT EL 278.00 Cw 3 .10 Ow1 CFS 0 .00 0 .55 1.55 2 .85 4 .38 07 "un-00 ROBERTSON CONSUL TING R. ROBERTSON 2 3 POND 0 .00 0 .00 OUTLET 0.00 0 .00 TOTAL 0 .00 0 .00 DISCHARC Qw2 CFS Qw3CFS ICFSl 0 .00 0 .00 0 .00 0 .00 0 .00 0 .55 0 .00 0 .00 1.55 0 .00 0 .00 2 .85 0 .00 0 .00 4.38 SPREADSHEET 3 : 2"S/delta T +OUTFLOW COMPUTATIONS PROJECT : LOCATION : CLIENT: EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ENTER COMPUTATION TIME INTERVAL IN MINUTE~ 2 .00 STORAGE STORAGE !OUTFLOW POINT ELEVA Tl< DEPTH "S" ·s· ·o· NO. CFEET\ IFT.\ ICU.-FT.1 IAC.-FT .1 ICFS\ 1 278.00 0 .00 0 .00 0 .00 0 .00 2 278.50 0 .50 172.75 0 .00 0 .55 3 279.00 1.00 1224.00 0 .03 1.55 4 279.50 1.50 3945.75 0 .09 2 .85 5 280.00 2 .00 9255.75 0 .21 4.38 DATE : 07-Jun-OO ENGINEER ROBERTSON CONSUL TING OESIGNERR. ROBERTSON LOG LOG 25/dt+O ·o· 2S/dt+O ICFS\ ICFSI ICFS\ 0.00 0 .00 0 .00 3 .43 -0 .26 0 .53 21 .95 0 .19 1.34 68 .61 0 .45 1.84 158.65 0 .64 2 .20 SPREADSHEET 4a: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 0.72 4 1.44 6 2.16 8 2.88 10 3.60 12 2.88 14 2.16 16 1.44 18 0.72 20 0.01 22 0.01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0.00 0.72 2.16 3.60 5.04 6.48 6.48 5.04 3.60 2.16 0.73 0.02 2YEARSTORM DATE: ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (25/dT-O)n (CFS) (CFS) 0.00 0.00 0.00 0.72 -1.13 1.03 -0.99 2.61 0.12 5.16 2.25 8.73 5.44 11.92 8.39 13.43 9.80 13.40 9.77 11.93 8.40 9.13 5.81 5.83 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0.00 0.93 1.01 1.25 1.46 1.64 1.77 1.81 1.81 1.77 1.66 1.50 SPREADSH E ET 4b: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW -r•n •1•n (MIN) (CFS) 0 0 .00 2 0.88 4 1.76 6 2.64 8 3 .52 10 4.40 12 3 .52 14 2.64 16 1.76 18 0 .88 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ·1·n-1 + ·1•n (CFS) 0 .00 0 .88 2 .64 4.40 6 .16 7 .92 7 .92 6 .16 4 .40 2.64 0 .89 0 .02 0 .02 0 .02 0 .02 0 .02 5 YEARSTORM DATE : ENGINEER: DESIGNER: ·1·n-1 + •1•n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0 .00 0 .00 0.88 -1.06 1.58 -0.64 3.76 1.05 7.2 1 4.06 11 .98 8.45 16.37 12.57 18.73 14.81 19.21 15.27 17.91 14 .04 14.93 11 .21 11 .23 7 .74 7 .76 4.56 4.58 1.75 1.n -0 .51 -0.49 07.Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 0 .97 1.11 1.35 1.57 1.77 1.90 1.96 1.97 1.94 1.86 1.74 1.60 1.42 1.14 ERR SPREADSHEET 4c : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOV HYDRO. TIME INFLOW "T"n •1•n (MIN) (CFS) 0 0 .00 2 1.00 4 2.00 6 3.00 8 4.00 10 5.00 12 4.00 14 3 .00 16 2.00 18 1.00 20 0.01 22 0 .01 24 0.01 26 0 .01 28 0.01 10 YEAR STORM EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ·i·n-1 + "l"n (CFS) 0 .00 1.00 3 .00 5 .00 7 .00 9 .00 9 .00 7 .00 5 .00 3 .00 1.01 0 .02 0 .02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -1.00 -0.34 1.81 5 .51 10.82 15.85 18.75 19.62 18.53 15.58 11 .85 8 .34 5 .10 DATE : ENGINEER: DESIGNER: ·1·n-1 + ·1·n + (2S/dT-O)n (CFS) 0 .00 1.00 2.00 4.66 8 .81 14 .51 19.82 22 .85 23.75 22 .62 19.54 15.60 11 .87 8 .36 5 .12 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OOTFLQIN ·o· (CFS) 0 .00 1.00 1.17 1.42 1.65 1.85 1.98 2.05 2.07 2.04 1.98 1.88 1.76 1.63 1.45 SPREADSHEET 4d: HYOROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT: LOCATION: CLIENT: INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 1.14 4 2.28 6 3.42 8 4.56 10 5.70 12 4.56 14 3.42 16 2.28 18 1.14 20 0.01 22 0.01 24 0.01 26 0.01 28 0.01 30 0.01 25 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ·i·n-1 + •1•n (CFS) 0.00 1.14 3.42 5.70 7.98 10.26 10.26 7.98 5.70 3.42 1.15 0.02 0.02 0.02 0.02 0.02 (2S/dT-O)n (CFS) 0.00 0.00 -0.92 O.Q3 2.75 7.28 13.68 19.80 23.49 24.85 23.97 20.93 16.93 13.12 9.53 6.20 DATE: ENGINEER: DESIGNER: "l"n-1 + "l"n + (25/dT-O)n (CFS) 0.00 1.14 2.50 5.73 10.73 17.54 23.94 27.78 29.19 28.27 25.12 20.95 16.95 13.14 9.55 6.22 07..Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 1.03 1.23 1.49 1.72 1.93 2.07 2.14 2.17 2.15 2.09 2.01 1.91 1.81 1.68 1.52 SPREADSHEET 4e: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT: INFL0\11 HYDRO. TIME INFLOW "T"n Tn (MIN) (CFS) 0 0.00 2 128 4 2.56 6 3 .84 8 5 .12 10 6.40 12 5.12 14 3 .84 16 2.56 18 128 20 O.o1 22 O.o1 24 0.01 26 0.01 28 0.01 30 0 .01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ·rn-1 + ·rn CCFSl 0 .00 128 3.84 6.40 8.96 11 .52 11 .52 8 .96 6.40 3 .84 129 0 .02 0 .02 0 .02 0 .02 0 .02 50 YEAR STORM DATE : ENGINEER : DESIGNER: (2S/dT-O)n (CFS) 0.00 0 .00 ..0 .84 0.43 3 .72 9 .10 16.62 23.84 28.34 30.23 29.58 26.47 2225 1820 14.33 10.66 ·rn-1 + "l"n + (2S/dT-O)n (CFSl 0 .00 128 3 .00 6 .83 12 .68 20.62 28.14 32.80 34.74 34.07 30.87 26.49 22 .27 1822 14.35 10.68 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 1.06 129 1.55 1.79 2 .00 2.15 2.23 226 225 2 .20 2.12 2 .04 1 .95 1.84 1.72 SPREADSHEET 4f: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: INFLQVI HYDRO. TIME INFLOW "T"n •rn (MIN) (CFS) 0 0.00 2 1.36 4 2.72 6 4.08 8 5.40 10 6.80 12 5.40 14 4.08 16 2.72 18 1.36 20 0.01 22 0,01 24 0.01 26 0,01 28 0.01 30 0.01 -100 YEAR STORM EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + •rn (CFS) 0.00 1.36 4.08 6.80 9.48 1220 1220 9.48 6.80 4.08 1.37 0.02 0.02 0.02 0.02 0.02 DATE: ENGINEER: DESIGNER: (2S/dT-O)n (CFS) 0.00 0.00 -0.79 0.66 429 10.12 18.25 26.07 31.01 3321 32.70 29.58 25.25 21.07 17.07 13.25 ·rn-1 + ·rn + (2S/dT-O)n (CFS) 0.00 1.36 3.29 7.46 13.n 22.32 30.45 35.55 37.81 37.29 34.07 29.60 25.27 21.09 17.09 13.27 07.Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0.00 1.07 1.31 1.59 1.83 2.04 2.19 227 2.30 229 225 2.18 2.10 2.01 1.92 1.81 DRAINAGE REPORT PROPOSED EAGLE A VENUE CHURCH COLLEGE STATION June 2000 Owner Stylecraft Builders Inc. 4112 SH 6 South College Station, Texas 77845 Engineer Robertson Consulting Engineers 1008 Woodcreek Drive College Station, Texas 77802 CERTIFICATION I hereby certify that this report and accompanying drainage plan for the drainage design of Proposed Eagle A venue Church was prepared by me in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof Registered Professional Engineer State of Texas No. 56375 Introduction The proposed project is located on Eagle Avenue immediately west of State Highway 6 in the Springbrook Subdivision. The project consists of a new building and site improvements for a 2 .099 acre tract. The site was originally part of a 5.751 acre tract which currently is occupied by Stylecraft Builders Inc. The lot for this project was replatted and separated from the original tract. Figure 1 shows the original drainage map for the Stylecraft project, taken from the drainage report prepared by McClure Engineering Inc . No portion of the project lies within the current boundaries of the regulatory 100-year Floodplain for the City of College Station. The project lies within the Lick Creek drainage basin. Existing Drainage Patterns The tract and relevant adjacent land areas that contribute runoff to it are undeveloped at this time . Existing land cover consists of natural grasslands . The site receives a substantial amount of off-site flows from areas to the north . The on-site and off-site stormwater flows are discharged to the east into a drainage channel in the adjacent drainage easement on the east side of the property. Proposed Drainage Patterns The proposed drainage patterns and improvements are depicted in Figure 2. Detailed calculations for the improvements are contained in Appendices A-B . The plans for this project depict the detailed construction necessary to accomplish the proposed drainage improvements and are made a part of this report . The north area identified as lB will continue to discharge into the channel in the drainage easement on the east side of the property. No detention is needed for this site on the north area, as no new construction on this site will occur. The offsite areas to the north of this tract are assumed to contribute no additional runoff to this site when they are developed . The south area identified as 1 A represents the developed portion of the tract. Detention is provided for this portion of the site utilizing a portion of the proposed parking area on the southeast comer of the site. The curb will be built higher at the outlet end of the detention area and have a 6" width curb opening discharging into a 2 foot width concrete outlet weir . The detention basin will collect all waters from the developed area of this site and will discharge directly into the existing channel and drainage easement. The detention area is designed to limit the discharge for the 2-year to 100-year storms from the proposed project to less than the discharge that existed prior to construction. Emergency overflow of the detention area will occur over the curb into the channel. The detention basin will pond water to a maximum elevation of 279 .25 feet during the 100-year storm . A combined summary of pre-and post-development peak discharges for the project is provided in Table 1. 2-year 5-year 10-year 25-y ear 50-year 100-year storm storm storm sto rm storm storm Existing 1.56 1.89 2 .12 2.4 3 2 .74 2 .86 Develop 3 .63 4.41 4 .95 5.6 5 6 .39 6 .67 Detained 1.81 1.97 2 .07 2 . 17 2 .26 2 .30 Table 1. Peak Project Discharge s (cfs) Conclusions ect in the application of the Although the calculations provided are numerically corr principles of hydraulics and hydrology, the actual numbers are b considered the accuracy of the underlying methodology. Calcula cfs, or even 1 cfs, is false accuracy when using any hydrologic m el ow the limits of what is ting discharges to the . 01 cfs, . 1 ethod . nge of design storms considered . This site originally discharged about 2-3 cfs over the ra If no detention is provided it will only discharge 4 -7 cfs from developed . The detention provided will reduce that discharge to the same storms when ultimately 2 -3 cfs . Within the accuracy of existing hydrologic methods, these numbers are the same. rainage requirements of the City That having been said, the proposed project meets the d of College Station . No higher peak stormwater flows will be dir existing drainage easement and channel, or the receiving storm ected to Eagle A venue, the sewer. - APPENDIX A DISCHARGE CALCULATIONS SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION : CLIENT: DRAINAG COMP. BASIN RUNOFF ID COEFF. 1A 0.30 1B 0.30 TOTAL 0.30 1A 0 .70 18 0.30 TOTAL 0.32 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. BASIN NATURAL WOODLANDS AREA AREA SLOPE RUNOFF (ACRES} (ACRES} (FT/FT) COEFF. EXIST. SITE 0.82 0.00 0.00 0.00 18 .00 0.00 0.00 0.00 18.82 0.00 0.00 0 .00 PROP. SITE 0 .82 0.00 0.00 0.00 18.00 0.00 0.00 0.00 18.82 0.00 0.00 0 .00 NATURAL GRASSLANDS AREA SLOPE RUNOFF {ACRES) {FT/FT) COEFF. 0.82 0 .01 0.30 18.00 0.01 0 .30 18.82 0.02 0.30 0.00 0.00 0.00 18.00 0.01 0.30 18 .00 0.02 0 .30 DATE: ENGINEER: DESIGNER: LANDSCAPED AREAS AREA SLOPE RUNOFF <ACRES} (FT/FT} COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.30 0.01 0.35 0.00 0.00 0.00 0.30 0.01 0.40 PAGE 1-L OF 1 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON IMPERVIOUS AREA SLOPE RUNOFF (ACRES} (FT/FT} COEFF. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.52 0 .01 0.90 0.00 0.00 0.00 0.52 0 .01 0.90 SPREADSHEET 1: BASIN LAND COVER COMPUTATION PROJECT: LOCATION: CLIENT: EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. LOW DENSITY RESIDENT MED. DENSITY RESIDEN1 AREA SLOPE RUNOFF AREA SLOPE RUNOFF (ACRES) (FT/FTI COEFF. <ACRES) CFT/FTI COEFF. 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0.00 0.00 HIGH DENSITY RESIDEN AREA SLOPE RUNOFF (ACRES) CFT/Fn COEFF . 0.00 0.00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0.00 0.00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 ' DATE: ENGINEER: DESIGNER: BUSINESS I COMMERCIA AREA SLOPE RUNOFF (ACRES) CFTIFT) COEFF . 0 .00 0.00 0.00 0.00 0.00 0.00 0 .00 O.Q1 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0.01 0.00 PAGE 1-R OF 1 07-Jun-00 0.00 0.00 INDUSTRIAL AREA SLOPE RUNOFF (ACRES) (FTIFT) COEFF. 0.00 0.00 0 .00 ·' 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0 .00 0 .00 0.00 0.00 0 .00 0.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT: DRAINAGI DESIGN BASIN "Tc" ID (MIN} EXIST. 1A 10.00 1B 35.00 TOTAL 35.00 PROP. 1A 10.00 1B 35 .00 TOTAL 35.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . CALC. NATURAL WOODLANDS "Tc" LENGTH SLOPE VELOCIT (MIN) (FEETI (FT/Fn (FT/SEC) SITE 10.00 0.00 35.00 0.00 35 .00 0.00 SITE 1.94 0.00 35 .00 0 .00 35.00 0.00 DATE: ENGINEER: DESIGNER: NATURAL GRASSLANDS LANDSCAPED AREAS LENGTH SLOPE VELOCIT LENGTH SLOPE VELOCIT (FEET) (FT/FT) (FT/SEC) CFEETI (FT/Fn (FT/SEC) 300.00 0.01 0.50 0.00 300 .00 0.01 0.50 0.00 300 .00 0 .01 0.50 0 .00 0.00 100.00 0.01 2.00 300 .00 0.01 0.50 0 .00 300.00 0.01 0.50 0.00 PAGE 1-L OF 1 07-Jun-00 0.00 0.00 LENGTH (FE En 0.00 0.00 0.00 200.00 0.00 0.00 PAVEMENT SLOPE (FT!Fn 0.01 VELOCITY (FT/SEC) 3.00 SPREADSHEET 2: BASIN TIME OF CONCENTRATION COMPUTATION PROJECT: LOCATION: CLIENT: PIPE LENGTH SLOPE (FE En (FT/FT) 0 .00 0 .00 0.00 0.00 0 .00 0.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. OPEN CHANNEL VELOCITY LENGTH SLOPE VELOCITY (FT/SEC) (FEET) (FT/Fn (FT/SEC) 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 ' NATURAL SWALE LENGTH SLOPE VELOCITY (FEET) (FT/FT) (FT/SEC) 0 .00 1500.00 0 .01 1.00 1500.00 0.01 1.00 0.00 1500 .00 0.01 1.00 1500 .00 0.01 1.00 DATE: ENGINEER: DESIGNER: SPREADSHEET 3: BASIN RAINFALL INTENSITY AND DISCHARGE COMPUTATIONS SHEET 1OF1 PROJECT: LOCATION : CLIENT: DRAINAG COMP . BASIN RUNOFI ID COEFF . 1A 0 .30 1B 0.30 TOTAL 0 .30 1A 0 .70 1B 0 .30 TOTAL 0 .32 EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . BASIN TIME OF 2YEARSTORM AREA CONC . "I" "Q" (ACRES (MIN) (IN/HR) (CFS) EXIST. SITE 0 .82 10.00 6 .33 1.56 18.00 35.00 3.14 16.93 18 .82 35.00 3 .14 17.70 PROP. SITE 0.82 10.00 6 .33 3.63 18.00 35 .00 3.14 16.93 18.82 35 .00 3.14 18.78 5YEARSTORM 10YEAR STORI "I " HQll "I" "Q" (IN/HR) (CFS) (IN/HR) (CFS) 7 .69 1.89 8 .63 2.12 3.93 21 .23 4 .50 24 .28 3.93 22 .20 4.50 25 .39 7 .69 4.41 8.63 4 .95 3 .93 21 .23 4 .50 24 .28 3 .93 23 .54 4 .50 26 .93 DATE : ENGINEER : DESIGNER : 07-Jun-OO ROBERTSON CONSULTING R. ROBERTSON 25YEAR STOR 50 YEAR STORM 100 YEAR STOF '*I" "Q" "I" "Q" "I" "Q" (IN/HR) (CFS) (IN/HR) (CFS) ON/HR) (CFS) 9 .86 2 .43 11 .15 2 .74 11 .64 2.86 5.18 27 .95 5 .90 31.84 6 .16 33 .28 5 .18 29.22 5.90 33.29 6 .16 34.80 9 .86 5 .65 11 .15 6 .39 11 .64 6.67 5.18 27 .95 5 .90 31 .84 6 .16 33 .28 5.18 30.99 5 .90 35 .30 6 .16 36 .91 APPENDIXB DETENTION CALCULATIONS SPREADSHEET 1: POND STORAGE COMPUTATIONS PROJECT: LOCATION : CLIENT: POINT ELEVA TIC NO . CFEETI 1 278 .00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE. CHURCH COLLEGE STATION , TX STYLECRAFT BUILDERS INC. AVERAGE POND ARE.I POND ARE POND ARE lSQ.-FT.} <ACRES} (SQ . ..f"T .} 0 .00 0 .00 0 .00 691 .00 0.02 345.50 3514.00 0 .08 2102 .50 7373 .00 0 .17 5443.50 13867.00 0 .32 10620.00 DATE: ENGINEER : DESIGNER: INCR . DEPTH DEPTH CFT.} CFT.} 0.00 0 .00 0.50 0 .50 1.00 0.50 1.50 0 .50 2.00 0.50 INCR. VOLUME CCU .-FTJ 0 .00 172 .75 1051 .25 2721 .75 5310.00 PAGE 1OF1 07..Jun-OO ROBERTSON CONSUL TING R. ROBERTSON TOTAL INCR. TOTAL VOLUME VOLUME VOLUME (CU .-FT.\ lAC .-FT.\ lAC.-FT.\ 0 .00 0 .00 0 .00 172.75 0 .00 0 .00 1224.00 0.02 0 .03 3945.75 0 .06 0 .09 9255.75 0 .12 021 SPREADSHEET 2: OUTLET WORKS DISCHARGE COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: POND WATER SURFACI: POINT ELEVA Tl< NO. /FEET\ 1 278.00 2 278.50 3 279.00 4 279.50 5 280.00 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. !ORIFICE N< 1 2 AREA, SF 0.00 0.00 INVERT 0.00 0.00 Co 0.00 0.00 Qo1 CFS Qo2 CFS 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3 0.00 0.00 0.00 Qo3CFS 0.00 0.00 0.00 0.00 0.00 DATE: ENGINEER: DESIGNER: IWEIRNO. 1 ENGTH, f 0.50 INVERT El 278.00 ON 3.10 Qw1 CFS 0.00 0.55 1.55 2.85 4.38 07--Jun-OO ROBERTSON CONSUL TING R. ROBERTSON 2 3 POND 0.00 0.00 OUTLET 0.00 0.00 TOTAL 0.00 0.00 OISCHARC CNl2. CFS Qw3CFS tCFSl 0.00 0.00 0.00 0.00 0.00 0.55 0.00 0.00 1.55 0.00 0.00 2.85 0.00 0.00 4.38 SPREADSHEET 3: 2*S/delta T + OUTFLOW COMPUTATIONS PROJECT : LOCATION : CLIENT: EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ENTER COMPUTATION TIME INTERVAL IN MINUTE~ 2.00 STORAGE STORAGE OUTFLOW POINT ELEVA TIC DEPTH "S" ·s · ·o· NO. CFEETl IFT.I CCU . ..fT.I IAC.-FT .1 CCFS\ 1 278.00 0 .00 0.00 0.00 0 .00 2 278.50 0.50 172.75 0.00 0 .55 3 279.00 1.00 1224.00 0.03 1.55 4 279.50 1.50 3945.75 0 .09 2.85 5 280.00 2.00 9255.75 0 .21 4.38 DATE : 07-Jun-OO ENGINEER ROBERTSON CONSUL TING DESIGNER R. ROBERTSON LOG LOG 25/dt+O ·o· 2S/dt+O ICFSI CCFSI CCFSl 0 .00 0 .00 0 .00 3 .43 -0 .26 0 .53 21 .95 0 .19 1.34 68.61 0 .45 1.84 158.65 0 .64 2 .20 SPREADSHEET 4a : HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT : LOCATION : CLIENT: INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS ) 0 0 .00 2 0.72 4 1.44 6 2 .16 8 2.88 10 3.60 12 2.88 14 2.16 16 1.44 18 0 .72 20 0 .0 1 22 0 .0 1 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 0.72 2 .16 3 .60 5.04 6 .48 6 .48 5 .04 3 .60 2 .16 0 .73 0 .02 2YEARSTORM DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (2 5/dT-O)n (CFS) (CFS) 0 .00 0 .00 0 .00 0 .72 -1.13 1.03 -0.99 2 .61 0 .12 5 .16 2 .25 8 .73 5 .44 11 .92 8.39 13.43 9 .80 13.40 9 .77 11 .93 8 .40 9.13 5 .81 5.83 07..Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0.00 0 .93 1.01 1.25 1.46 1.64 1.77 1.81 1.8 1 1.77 1.66 1.50 SPREADSHEET 4b: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT : LOCATION : CLIENT : INFLO\I HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 0.88 4 1.76 6 2.64 8 3.52 10 4 .40 12 3 .52 14 2 .64 16 1.76 18 0 .88 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. "l"n-1 + ·1•n (CFS) 0 .00 0 .88 2 .64 4 .40 6.16 7 .92 7 .92 6 .16 4 .40 2 .64 0 .89 0 .02 0 .02 0 .02 0.02 0 .02 5 YEARSTORM DATE: ENGINEER: DESIGNER: "l"n-1 + "l"n + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0 .00 0 .00 0.00 0 .88 -1.06 1.58 -0.64 3 .76 1.05 7 .21 4.06 11 .98 8.45 16.37 12 .57 18.73 14.81 19.21 15.27 17.91 14.04 14.93 11.21 11 .23 7.74 7 .76 4 .56 4 .58 1.75 1.77 -0 .51 -0 .49 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0.00 0.97 1.11 1.35 1.57 1.77 1.90 1.96 1.97 1.94 1.86 1.74 1.60 1.42 1.14 ERR SPREADSHEET 4c: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT : LOCATION : CUENT: INFLOV HYDRO . TIME INFLOW "T"n "l "n (MIN) (CFS) 0 0.00 2 1.00 4 2.00 6 3 .00 8 4.00 10 5 .00 12 4 .00 14 3.00 16 2.00 18 1.00 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0.01 1 O YEAR STORM EAGLE AVE. CHURCH COLLEGE ST A TION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.00 3 .00 5 .00 7 .00 9 .00 9 .00 7 .00 5.00 3 .00 1.01 0 .02 0 .02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0 .00 -1.00 -0 .34 1.81 5 .51 10.82 15.85 18.75 19.62 18.53 15.58 11 .85 8 .34 5 .10 DATE : ENGINEER : DESIGNER: ·1·n-1 + "l"n + (2S/dT-O)n (CFS) 0 .00 1.00 2.00 4.66 8 .81 14 .51 19 .82 22 .85 23 .75 22 .62 19.54 15.60 11 .87 8 .36 5 .12 07.Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 1.00 1.17 1.42 1.65 1.85 1.98 2.05 2.07 2.04 1.98 1.88 1.76 1.63 1.45 SPREADSHEET 4d : HYOROGRAPH ROUTING COMPUTATIONS PAGE 1 OF 1 PROJECT : LOCATION : QIENT: INFLOV HYDRO. TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0.00 2 1.14 4 2.28 6 3.42 8 4.56 10 5.70 12 4 .56 14 3.42 16 2.28 18 1.14 20 0.01 22 0 .01 24 0 .01 26 0.01 28 0 .01 30 0 .0 1 25 YEAR STORM EAGLE AVE. CHURCH COLLEGE ST A TION, TX STYLECRAFT BUILDERS INC. "l"n-1 + "l"n (CFS) 0 .00 1.14 3 .42 5 .70 7 .98 10.26 10.26 7 .98 5 .70 3.42 1.15 0 .02 0 .02 0 .02 0 .02 0 .02 (2SldT-O)n (CFS) 0 .00 0.00 -0 .92 0 .03 2.75 7 .28 13.68 19.80 23 .49 24 .85 23 .97 20.93 16.93 13.12 9 .53 6.20 DATE : ENGINEER: DESIGNER: "l"n-1 + "l"n + (2SldT-O)n (CFS) 0 .00 1.14 2.50 5 .73 10.73 17.54 23.94 27 .78 29.19 28.27 25.12 20.95 16.95 13 .14 9 .55 6 .22 07-Jun-OO ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW ·o· (CFS) 0 .00 1.03 1.23 1.49 1.72 1.93 2.07 2.14 2.17 2.15 2.09 2.01 1.91 1.81 1.68 1.52 SPREADSHEET 4e: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT: LOCATION: CLIENT: INFLQVI HYDRO. TIME INFLOVV "T"n "l"n {MIN) (CFS) 0 0.00 2 128 4 2.56 6 3.84 8 5.12 10 6.40 12 5.12 14 3.84 16 2.56 18 128 20 0.01 22 0.01 24 0.01 26 0.01 28 0.01 30 O.G1 EAGLE AVE. CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC. ·rn-1 + ·rn (CFS) 0.00 128 3.84 6.40 8.96 11.52 11.52 8.96 6.40 3.84 1.29 0.02 0.02 0.02 0.02 0.02 50 YEAR STORM DATE: ENGINEER: DESIGNER: ·rn-1 + •rn + (2S/dT-O)n (2S/dT-O)n (CFS) (CFS) 0.00 0.00 0.00 128 -0.84 3.00 0.43 6.83 3.72 12.68 9.10 20.62 16.62 28.14 23.84 32.80 28.34 34.74 30.23 34.07 29.58 30.87 26.47 26.49 22.25 2227 18.20 1822 14.33 14.35 10.66 10.68 07-Jun--00 ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0.00 1.06 1.29 1.55 1.79 2.00 2.15 2.23 226 2.25 220 2.12 2.04 1.95 1.84 1.72 SPREADSHEET 4f: HYDROGRAPH ROUTING COMPUTATIONS PAGE 1OF1 PROJECT : LOCATION : CLIENT : INFLOY HYDRO . TIME INFLOW "T"n "l"n (MIN) (CFS) 0 0 .00 2 1.36 4 2 .72 6 4 .08 8 5.40 10 6 .80 12 5.40 14 4.08 16 2 .72 18 1.36 20 0 .01 22 0 .01 24 0 .01 26 0 .01 28 0 .01 30 0 .01 -100 YEAR STORM EAGLE AVE . CHURCH COLLEGE STATION, TX STYLECRAFT BUILDERS INC . "l"n-1 + "l"n (CFS) 0.00 1.36 4 .08 6.80 9 .48 12.20 1220 9 .48 6 .80 4 .08 1 .37 0.02 0 .02 0.02 0 .02 0 .02 (2S/dT-O)n (CFS) 0 .00 0.00 -0.79 0 .66 429 10.12 18.25 26.07 31 .01 3321 32.70 29.58 25.25 21.07 17.07 13.25 DATE : ENGINEER : DESIGNER: Tn-1 + Tn + (2S/dT-O)n (CFS) 0.00 1.36 329 7.46 13.n 22 .32 30.45 35.55 37.81 3729 34.07 29 .60 2527 21 .09 17.09 1327 07-Jun--00 ROBERTSON CONSUL TING R. ROBERTSON OUTFLOW "O" (CFS) 0 .00 1.07 1 .31 1 .59 1 .83 2 .04 2 .19 2 .27 2.30 2 .29 2 .25 2 .18 2 .10 2 .01 1.92 1.81