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Home My WebLink About41 Development Permit 237 KFO Mini Storage4-14-~4 .i: SPD~ er iA"'~ ~'-~ve-'-rf&oc.1r nTr!1' c~tSC'3 ~ ~T>-c.r/j}~ TO 17'n$ ~oc./at.:r; ~ /'7'0~ ~S:- ~G C?.S \IV'e>Cl'c..p ~~~ /?7b-044YA./~C:-09<-CS - e>f-;2c. rcc.J:> ,_,e-~ ~ ,?>Tecrt#qr-~ S,?l:r-vvouc.o C/7'rlr./fl-r:7 &a ~U'~ ~ ~ A'r::?Vd"C-V ~er /Vl)r /l:) c~ 7'7ts" ~~~ ~ ~..s 771¥?e. (:;:'~(_ S4'70 ~ ~ O...V~y /~~cu-~ Cl>VGe;;> ~JC:. ~ /5 ~ £ 41::--V/c:~ ~.s ~~occ:s....s ~ 0&/?::ii>V./lON 0"'7L~ S~C/c.TU~ TO "'1"??¢1e.C: S"/ZC:- 1/-er '~ ~~ ~# :r S~P ~ ..;: ~ /dy 70 t..eJOH:.... ~r-QV'C-~ ~ c..rrr m~ ~(Tz...,, /,,,,, ~s-~ ~ ~ s:5) DRAINAGE COMPUTATIONS For Lot 5, Block 1 K.F.O. Addition College Station, Brazos County , Texas Prepared By: Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan , Texas 77802 Telephone : (409) 846-2688 *April, DRAINAGE COMPUTATIONS For A Mini-Storage Complex To Be Located Lot 5, Block 1 K.F.O. Addition College Station, Braz os Co unty , Tex as * April , 199 4 * SUMMARY The project consists of th e construction of a buildin g and co ncrete driveway s to facilitate a propose d mini-storag e warehouse. It i s propo sed that a detenti on fac ility be co nstructed to sto r e th e excess sto nnwater run-o ff as a r es ult of th e site improvemetn s. The detention faci lity will be constructed in a gree n area (See site and gradin g plan) and i s des i gned to facilitate th e 100-year stonn eve nt. The dete ntion pond will store and m eter run-off from th e roof of th e aforesaid building, and propo sed concrete driveway . From the computations on pag e 1 based on th e proj ec t area of 0.70 acre s as shown on th e aforementioned Site & Gradin g Pl an, th e predeve lopm ent run -off coe fficient being assumed at 0.40 and a minimum tim e of co ncentrati on of 10 minutes th e relative predeve lopm ent peak discharge rates ("Q") were dete nnined . The intensities shown on pa ge 1 were tak en from "Figure III-1 Intensity Duration Freciu ency Curves For The City Of College Station"as contained in U1 e "Drainage Poli cy and Design Standard s for th e City of College Stati on" ass uming sam e minimum tim e of co nce ntrat i on of 10 minutes. The R ational Meiliod was utilize d to co mpute U1 e es timated peak predevel opm ent di sc harge rates. The equ ation Urnt represe nts Ul e R ational M ethod i s as follows: Q = CIA, wh ere; "Q" i s U1 e peak di sc harge rate in cubic fee t per seco nd . "C" i s Ul e run-off coe fficient, in U1 e predevelopment co nditi on "C" i s ass umed to be 0.40, "I" is Ul e storm intensity in in ches per hour and "A " which i s Ul e area of Ul e site in acres. From Ul e computations on pa ge 2 based on Ul e project area of 0.70 ac r es, ilie postdeve lopm ent run-off coefficient being ass umed at 0.90 and a minimum time of co nc entration of 10 minutes the rel ative predeve lopm ent peak di sc harge rates ("Q") were detennined. The inten siti es shown on pa ge 1 were tak en from "Figure III-I Intensity Duration F requ ency C urves For The City Of College St ation"as co ntain ed in U1 e "Drainage Policy and Design Standards for U1 e City of College Stati on" ass umin g sam e minimum time of co nc entrati on of 10 minutes. T he R ati onal Meiliod was uti lize d to compute Ul e estimated peak post development discharge rates . The equation Urnt represe nts Ul e Rational Method i s as follows: Q = CIA, where; "Q" i s U1 e peak di sc harge rate in cubi c feet per seco nd . "C " i s U1 e run-off coefficient, in th e post development co ndition "C" i s ass um ed to be 0.90, "I" i s th e sto nn intensi ty in inches per ho ur and "A" which i s U1 e area of Ul e site in ac r es. The comparison between peak predeve lopment discharge rates and po st development discharge rates i s included as an aid to U1 e des i gner to es tablish a preliminary "targe t" as to U1 e volume necessary in Ul e propo sed detention facility. This preliminary es timate i s arrived at by simply detennining Ul e volume genera ted from Ul e difference of Ul e predeve l op ment and po st development hydrograp hs (see pages 7-9 for predevelopment and po st deve l opm ent hydro grap hs). Pl ease note Ulat U1 e pos t deve l opm ent hydro gra ph show n on th ese sam e graph s assumes no detention. Page 3 pro vides co mputaio ns w hi ch determine Ule pos td evelop ment run -off Ul at i s to be routed Ulrou gh U1 e detention fac ility. Page 4 and page 5 are tabulations of U1 e prede velopment hydro grap h and th e po st development hydrog raph based on Ul e computations perfonned on page 1 and page 2. The post development hydrograph ass um es no detention to faci litate direc t comparison in Ul e pre and pos t development co ndition s. Computations on pa ge 3 deter mine U1 e ac tual peak postd eve lopm ent "inflow" rates suppli ed to U1 e proposed detention facility . From U1 ese "inflow" rates and Ule time of concentration (10 minutes minimum), hydro graph s as tabul ated on page 6 ca n be derived. The hydrograph s are trian gular in shap e and are b ased on Ule standard SCS unit hydrog raph wiili time to peak se t eq ual to Ul e tim e of co nc entration and the total tim e base se t at 2.6 7 tim es U1 e time of concentration. Pl ease note Ulat a 26.7 minute total sto nn eve nt duration was utilized exc lu sively Ulrou ghout Uli s report du e totally to Ul e small physical size of Ul e proj ect. Having deri ved Ul e preliminary volume requirements and "allowabl e peak " di sc harge rates it i s now possible to design U1 e fin al detention facility and outlet co ntro l structure. Page 10 prese nts a tabulation and depili ve rses volume graph of U1 e detenti on facility. Please note Ul at U1 e site pl an was utilize d to determine Ul e vo lum e and depilis for tabulation as menti oned abov e. T he max imum depili of Ul e pond was se t at 2.59' (to p benn : 296.10 l ess fl owline "o ut" of outl et co ntrol struct ure: 293.5 1 = 2.59'). Page 11 supplies a tabul at i on and ratin g curve fo r t11 e propo sed outl et co ntrol stru cture. A rec tangular weir was dec id ed upon due to depili verses di sc har ge ratio characteri stics assoc i ated wiUl a shallow headw ater dept11 (maximum of 2.59d and tl1 e narro w widili of Ule w eir (3-1/2"). T he equ atio n used to detennine disc har ge w as Q = CLH3 / where "Q" is Ul e di sc harge rate in cubic fee t per seco nd. "C" is Ul e coeffic i ent of discharge, in Uli s case ass um ed to be se t at 3.087," L" bein g U1 e widili of Ul e weir in fee t in tl1i s case L i s se t at 0.29 feet (3 -1/2 ") and "H'' being th e hea dwater deptl1 in feet (ranges from O' to 2.59'). Page 12 prese nts a tab ul atio n of tl1 e rel ati onship between di sc har ge from Ul e detention and U1 e dimensionless quantity 2S/t-O and Storage Indication Curve for U1 e detention faci lity based on Ul e aforementioned phy sical characte ri sti cs of t11 e dete ntion pond , storage vo lume, inflow hydrogra ph , rating curve for tl1 e outl et structure. The storage indi cat i on curve as shown on page 12 i s a gra phical so lution to t11 e equation presented in t11 e"Dra in age Policy And Design Standards" as follows: 2s 1 (I 1 + 12) + (--------------- dt 2s2 -0 i ) = (-----------------+ 02) dt Page 13 prese nts ta bulated data for Ul e 2-year storm eve nt. T he maximum depili ac hi eved in Ul e detention pond durin g t11is simulation i s 1.25 fee t and occ urs between 19 minutes and 20 minutes after Ul e beg inning of tl1e sto rm eve nt. T he calculated peak di sc harge rate corresponding to Uli s dept11 ove r sam e per i od i s 1.25 cubic fee t per seco nd . The max imum w ater sur face el eva ti on ac hieved durin g Uli s eve nt i s 294 .76 m sl. T he es timated velocity of U1 e max imum peak discharge durin g Uli s sam e eve nt is 3.4 5 feet per seco nd. Page 14 represe nts tl1 e predevelopment hydrogra ph , Ul e po st deve l op ment hydrogra ph (wiUl no detention) and Ul e po st deve lopm ent bydro gra ph as routed U1rough tl1 e dete ntion pond for t11 e 2-year storm eve nt. Page 15 prese nts tab ulated data for Ul e 5-year storm eve nt. The max imum depUl achieved in Ul e detention pond durin g t11i s simulati on i s 1.68 feet and occ urs at 20 minutes after tll e beg innin g of tll e sto nn eve nt. The calculated peak di sc har ge rate corresponding to tl1i s deptll ov er sam e period i s 1.95 cubic fee t per seco nd. The max imum water surface el eva ti on ac hi eved during U1i s event i s 295.19 msl. The es timated ve l oc ity of U1 e maximum peak discharge durin g tllis same even t i s 4.00 feet per seco nd . Page 16 rep rese nts Ule predev elopment hydrograph , Ul e post deve lopment hydrograph (witll no detention) and th e po st development hydrogra ph as routed Ulrou gh Ule dete ntion pond for Ul e 5-year storm eve nt. Page 17 prese nts tabulated data for U1 e IO -year sto rm event. The max imum depth achieved in Ule dete ntion pond during U1i s simulation i s 1.82 feet and occurs between 19 minutes and 21 minutes afte r U1 e beginning of Ul e stonn eve nt. The calculated peak di sc har ge rate corresponding to Uli s depili over same per iod i s 2.21 cubic feet per seco nd . The maximum water surface elevation achieved during Uli s eve nt i s 295.33 msl. The es tim ated velocity of Ule maximum peak discharge durin g U1i s sam e event i s 4.17 feet per seco nd. Page 18 represe nts Ule pred evelopment hydrogra ph , Ul e post development hydro gra ph (wiili no detention) and Ul e post deve lopm ent hydro graph as routed Ulrou gh U1 e detention pond and pos tdeve lopm ent "free -flow" hydro gra ph for th e 10-year stonn eve nt. Page 19 presents tabulated data for U1 e 25 -year storm event. The maximum depth achieved in Ul e detention pond durin g U1i s simulat i on i s 2.03 feet and occurs at 19 minutes afte r Ule beg inning of Ul e stonn event. The calculated peak di sc harge rate co rres pon di ng to Uli s depili over sam e period i s 2.58 cubic feet per seco nd . The m ax imum water surface el evati on achieved during Uli s eve nt i s 295.5 4 m sl. The estimated ve l oc ity of Ule maximum peak discharge during U1i s sam e eve nt i s 4.40 feet per seco nd. Page 20 rep rese nts Uw pred evelopm ent hydrograph , U1 e po st deve l opm ent hydrograph (with no detention) and U1 e po st development hydro graph as routed Ulfough Ul e detention pond fo r Ul e 25-year stonn event Page 21 prese nts tabulated data for Ul e 50-year storm eve nt. The maximum dep ili achieved in Ul e detention pond during Uli s simul ation is 2.23 feet and occurs between 19 minutes and 20 minutes after Ule beg inning of U1 e storm eve nt. The ca lculated peak di sc har ge rate corresponding to this deptll over sam e period is 2.98 cubic fe et per seco nd . The maxi mum wat er surface elevation achieved durin g U1i s eve nt is 295.74 m s!. The est imated ve l oc ity of U1 e maximu m peak di charge durin g Ulis same eve nt is 4.61 feet per seco nd . Page 22 represe nts U1 e predevelopment hydrogra ph , U1 e post deve lop ment hydro graph (wiili no detention) and the post development hydro gra ph as routed Ulrough U1 e detention pond for Ule 50-year storm event Page 23 presents tabulated data for U1 e 100-year storm eve nt. The maximum dep ili ac hieved in Ul e detention pond during Uli s simulation i s 2.44 feet and occurs between 19 minutes and 20 minutes after Ul e beginning of the storm eve nt. The calculated peak di sc harge rate corresponding to Ulis depili over same period i s 3.40 cubic feet per seco nd . The maximum water surface el evatio n achieved during U1i s eve nt i s 295.95 msl. T he esti mated velocity of U1 e max imum peak discharge durin g U1is sam e event i s 4.82 feet per seco nd . Page 24 rep resents U1 e predevelopment hyd rogra ph , U1e post deve l op ment hydrog raph (witll no detention) and U1 e po st development hydrogra ph as routed Ulrough Ul e detention pond for Ul e 100-year storm eve nt. Page 25 Ulfoug h page 30 provide total inflow /outflow hydro graphs for U1e 2, 5, 10 , 25, 50 and 100-year predevelopment and po st development sto rm eve nts. It can be determin ed from Ul ese sa.in e hydrograph s Ul at Ul e po st development peak discharge rates have been minutely decreased from Ulo se peak predevelopment discharge rates due to Ul e incorpora tion of Ul e detention fac ility in Ule po st development conditio n. Postde ve lopment peak di scharge ra tes from th e de tention pond outl et contro l structure and proj ec t site are kept less th a n th e prede velopm ent peak di sc harge rates du e to th e incorpora tion of th e propo sed de te ntion fac ilities witl1 sub sequ e nt pe ak pos td eve lopm e nt di sc harge ve lociti es proj ec ted to be well within man ageabl e limits. Determine Total Pre-Development Peak Storm Water Discharge Rates Tributary Area ("A"): 0.70 Acres Pervious Area : 0.70 Acres Impervious Area : 0.00 Acres Run-Off Coefficient ("Cwt"): 0.40 Time Of Concentration ("T/c"): Woodlands: Low Elevation : High Elevation: Distance (Feet): Slope(% Grade): Velocity ("Vw"): Time: Pastures: Low Elevation : High Elevation : Distance (Feet): Slope (% Grade): Velocity ("Vp "): Time: Pavements: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vpave"): Time: Total Travel Time : Hourly Intensity Rates ("I"): 2-Year: 5.20 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11 .15 100-Year: 12 .60 Peak Discharge Rate ("Q"): 2-Year: 1.46 5-Year: 2.15 10-Year: 2.42 25-Year: 2.76 50-Year : 3.12 100-Year: 3 .53 C= 0.40 C= 0.98 0.00 0.00 0.00 0.00 0.00 Feet I Second 0.00 Minutes 0.00 0.00 0.00 0.00 0.00 Feet I Second 0.00 Minutes 0.00 0.00 0.00 0.00 0.00 Feet I Second 0.00 Minutes 10.00 Minutes Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post-development Peak Storm Water Dischar e No Detention Tributary Area ("A"): 0.70 Acres Pervious Area : 0.10 Acres Impervious Area : 0.60 Acres Run -Off Coefficient ("Cwt"): 0.90 Time Of Concentration ("T/c"): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 5.20 5-Year: 7.70 10-Year: 8.60 25-Year: 9.90 50-Year: 11 .20 100-Year: 12 .60 C = 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Peak Discharge Rate ("Q"): 2-Year: 3 .27 Cubic Feet I Second 5-Year: 4.84 Cubic Feet I Second 10-Year: 5.40 Cubic Feet I Second 25-Year: 6.22 Cubic Feet I Second 50-Year: 7.03 Cubic Feet I Second 100-Year: 7.91 Cubic Feet I Second Comparison Of Predevelopment And Post-development Peak Discharge Rates Predevelopment Post-Development 2-Year: 1 .46 Ft3/sec 3.27 Ft3 /sec 5-Year: 2.15 Ft3/sec 4 .84 Ft3 /sec 10 -Year : 2.42 Ft3/sec 5.40 Ft3/sec 25 -Year : 2.76 Ft3/sec 6.22 Ft3 /sec 50-Year: 3.12 Ft3 /sec 7.03 Ft3 /sec 100-Year: 3 .53 Ft3/sec 7.91 Ft3 /sec Preliminary Determination Of Detention Pond Volume 2-Year: 1.81 Ft3 /sec x (26 .7 Min . x 60 Sec . I 2 ) = 5-Year: 2 .68 Ft3/sec x (26 .7 Min. x 60 Sec . I 2 ) = 10-Year: 2.98 Ft3 /sec x (26 .7 Min . x 60 Sec . I 2 ) = 25-Year: 3.46 Ft3 /sec x (26 .7 Min . x 60 Sec. I 2 ) = 50-Year: 3 .91 Ft3 /sec x (26 .7 Min . x 60 Sec. I 2 ) = 100-Year: 4.38 Ft3 /sec x (26.7 Min. x 60 Sec . I 2 ) = Increase 1.81 Ft3 /sec 2.68 Ft3 /sec 2.98 Ft3/sec 3.46 Ft3/sec 3 .91 Ft3/sec 4 .38 Ft3 /sec 1,449 Cubic 2,148 Cubic 2,389 Cubic 2,768 Cubic 3 ,134 Cubic 3 ,512 Cubic Feet Feet Feet Feet Feet Feet Determine Post-Development Flow Into Detention Pond Tributary Area ("A"): 0.70 Acres Pervious Area : 0.10 Acres Impervious Area : 0 .60 Acres Run-Off Coefficient ("Cwt"): 0.90 Time Of Concentration ("T/c"): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 5.20 5-Year: 7.70 10-Year: 8.60 25-Year: 9.90 50-Year: 11 .20 100-Year: 12 .60 Peak Discharge Rate ("Q "): 2-Year: 3 .27 5-Year: 4 .84 10-Year: 5.40 25-Year: 6.22 50-Year: 7.03 100-Year: 7.91 C= 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Pre-Development Storm Intensity Rates (Inches Per Hour) Time 2-Year 5-Year 10-Year 25-Year so-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.15 0.22 0.24 0.28 0.31 0.35 2 0.29 0.43 0.48 0.55 0.62 0.71 3 0.44 0.65 0.73 0.83 0.94 1.06 4 0.58 0.86 0.97 1.10 1.25 1.41 5 0.73 1.08 1.21 1.38 1.56 1.76 6 0.87 1.29 1.45 1.66 1.87 2.12 7 1.02 1.51 1.69 1.93 2.18 2.47 8 1.16 1.72 1.93 2.21 2.50 2.82 1.31 1.94 2.18 2.49 2.81 3.18 Peak=> r -1"6-=-"1.46" =--2.15_ __ 2.42:-~ 2.7s_-::. "3_1i-~.~~ 11 1.37 2.02 2.27 2.60 2.93 3.32 12 1.28 1.90 2.13 2.43 2.75 3.11 13 1.19 1.77 1.98 2.27 2.56 2.89 14 1.11 1.64 1.84 2.10 2.37 2.68 15 1.02 1.51 1.69 1.93 2.19 2.47 16 0.93 1.38 1.55 1.77 2.00 2.26 17 0.85 1.25 1.40 1.60 1.81 2.05 18 0.76 1.12 1.26 1.44 1.63 1.84 19 0.67 0.99 1.11 1.27 1.44 1.63 20 0.58 0.86 0.97 1.11 1.25 1.42 21 0.50 0.74 0.83 0.94 1.07 1.20 22 0.41 0.61 0.68 0.78 0.88 0.99 23 0.32 0.48 0.54 0.61 0.69 0.78 24 0.24 0.35 0.39 0.45 0.50 0.57 25 0.15 0.22 0.25 0.28 0.32 0.36 26 0.06 0.09 0.10 0.12 0.13 0.15 27 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development Storm Intensity Rates (Inches Per Hour) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Stqrm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 0.33 0.48 0.54 0.62 0.70 0.79 2 0.65 0.97 1.08 1.24 1.41 1.58 3 0.98 1.45 1.62 1.87 2.11 2.37 4 1.31 1.93 2.16 2.49 2.81 3.17 5 1.63 2.42 2.70 3.11 3.52 3.96 6 1.96 2.90 3.24 3.73 4.22 4.75 7 2.29 3.38 3.78 4.35 4.92 5.54 8 2.61 3.87 4.32 4.97 5.63 6.33 9 2.94 4.35 4.86 5.60 6.33 7.12 --n -~ -Peak=> L 10 3.27 4.84 5.40 6.22 7.03 7.91 ~ . -. . --11 3.07 4.55 5.08 5.84 6.61 7.44 12 2.87 4.26 4.75 5.47 6.19 6.97 13 2.68 3.97 4.43 5.10 5.77 6.49 14 2.48 3.68 4.11 4.73 5.35 6.02 15 2.29 3.39 3.78 4.36 4.93 5.54 16 2.09 3.10 3.46 3.98 4.51 5.07 17 1.90 2.81 3.14 3.61 4.09 4.60 18 1.70 2.52 2.81 3.24 3.66 4.12 19 1.51 2.23 2.49 2.87 3.24 3.65 20 1.31 1.94 2.17 2.49 2.82 3.17 21 1.11 1.65 1.84 2.12 2.40 2.70 22 0.92 1.36 1.52 1.75 1.98 2.23 23 0.72 1.07 1.20 1.38 1.56 1.75 24 0.53 0.78 0.87 1.01 1.14 1.28 25 0.33 0.49 0.55 0.63 0.72 0.81 26 0.14 0.20 0.23 0.26 0.29 0.33 27 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development Flow Routed Through Detention Pond Storm Intensity Rates (Inches Per Hour) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.33 0.48 0.54 0.62 0.70 0.79 2 0.65 0.97 1.08 1.24 1.41 1.58 3 0.98 1.45 1.62 1.87 2.11 2.37 4 1.31 1.93 2.16 2.49 2.81 3.17 5 1.63 2.42 2.70 3.11 3.52 3.96 6 1.96 2.90 3.24 3.73 4.22 4.75 7 2.29 3.38 3.78 4.35 4.92 5.54 8 2.61 3.87 4.32 4.97 5.63 6.33 9 2.94 4.35 4.86 5.60 6.33 r 10 -3~2r ·--;r34 ~ Peak=> 5.40 6.22 --7.03 ----< . -11 3.07 4.55 5.08 5.84 6.61 12 2.87 4.26 4.75 5.47 6.19 6.97 13 2.68 3.97 4.43 5.10 5.77 6.49 14 2.48 3.68 4.11 4.73 5.35 6.02 15 2.29 3.39 3.78 4.36 4.93 5.54 16 2.09 3.10 3.46 3.98 4.51 5.07 17 1.90 2.81 3.14 3.61 4.09 4.60 18 1.70 2.52 2.81 3.24 3.66 4.12 19 1.51 2.23 2.49 2.87 3.24 3.65 20 1.31 1.94 2.17 2.49 2.82 3.17 21 1.11 1.65 1.84 2.12 2.40 2.70 22 0.92 1.36 1.52 1.75 1.98 2.23 23 0.72 1.07 1.20 1.38 1.56 1.75 24 0.53 0.78 0.87 1.01 1.14 1.28 25 0.33 0.49 0.55 0.63 0.72 0.81 26 0.14 0.20 0.23 0.26 0.29 0.33 27 0.00 0.00 0.00 0.00 0.00 0.00 ... Cl> ~ -Cl> Cl> LA- Total Pre-Development Hydrograph Vs. Total Post- Development Hydrograph For 2-Year Storm Event Qi ~ 3 .oo------+----~t---'------t--------r-----i-----~ Q) ~ 2 .50..._------1----.0l<---l----..31io.--l-----+----+----~ 0 ...... ·-"O 2 00 ,._ ___ ---l--l----1------l-------+----+------; .a c . :J 0 0 0 ....., Cl> 1.50 +----~-----:Jt::::------t----~----r-----j Cl> V> O> o l.OO.._-~L._-+---,_,£------if----__::""'-::------+----"'....,_--+-----~ .c. ~ 0.50 .._-l---,_,£--+--------if------+------+="'"-::---~+-----~ 0 .00 ~--~ ...... ---+----+----+----+.;;::a..----t 0 5 10 15 20 25 3( nme (Minutes) ---Pre-Development Hydrograph ----Total Post-Development Hydrograph 5.00 4 .50 4 .00 3.50 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event 0 ...... :0 "O 3.00 :J c u 8 2.50 ; ~ 2.00 O> 1.50 ... 0 .c. l.00 0 II) 0 .50 0 0 .00 0 5 ---Pre-Development Hydrograph 10 15 20 25 30 nme (Minutes) ----Post-Development Outflow Hydrograph Without Detention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Event 0 .00 ~----+---.....ji-----+-----+----....-----4 0 5 10 ----Pre-Development Hydrograph 15 20 25 30 Time (Minutes) ----Post-Development Outflow Hydrograph Without Detention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 7.00 ... Q) ~ -6.00 Q) Q) 5.00 LL. 0 ....... ·-"O .0 c 4.00 :::> 0 () 0 3 .00 ........ Q) Q) Cf) 0) 2.00 ... 0 .c 0 l.00 Ill a 0.00 0 5 ---Pre -Development Hydrograph 10 15 20 25 30 Time (Minutes) ----Post-Development Outflow Hydrograph Without Detention 8 .00 ... Q) 7 .00 ll.. -Q) 6 .00 Q) LL. .2 u 5 .00 ..0 c 8 8 4 .00 ........ Q) 3 .00 Q) Cl) {)) ... 2.00 0 ..c 0 1.00 I/) i5 0 .00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 50-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 ---Pre-Development Hydrograph Post-Development Outflow Hydrograph Wit h out Detention 8 .00 ... Q) 7 .00 ll.. -Q) 6 .00 Q) LL. .2 u 5 .00 ..0 c 8 8 4 .00 ........ Q) 3 .00 Q) Cl) {)) ... 2.00 0 ..c 0 l.00 I/) i5 0 .00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 100-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 Pre-Development Hydrograph ----Post-De velopme nt Outflow Hydrograph Without Detention Detention Pond De th Vs. Volume Elevation Depth Volume (Feet) (Ft3) 293 .51 0 .00 0 293 .88 0.37 263 294.50 0 .99 1 ,197 295 .00 1.49 2 ,012 295 .50 1.99 2 ,867 296 .10 2 .59 3 ,944 Detention Pond Depth Vs. Volume 2.00 "" -Cl> Cl> u.. ....... 1.50 .i::. -a. Cl> 0 l.00 0 500 l ,000 l ,500 2 ,000 2 ,500 3 ,000 3 ,500 4 ,000 Detention Pond Volume (Cubic Feet) Rating Curve For Outlet Control Structure Weir Length(l): 0 .29 (3-1/2") De th Vs. Volume Elevation Depth Discharge (Feet) Ft3/Sec 293 .51 0.00 0 .00 293 .88 0.37 0 .20 294 .50 0 .99 0 .88 295 .00 1.49 1.63 295 .50 1.99 2.51 296 .10 2.59 3 .73 Rating Curve For Outlet Control Structure Depth Vs. Volume 2.00 --Q) Q) LL. .._, 1.50 .i= -a. Q) a 1.00 0 .00 0.50 1.00 1.50 2 .00 2.50 3.00 3.50 4.00 Discharge (Cubic Feet Per Second) I Storage Indication Curve Depth Storage Disc harge 2s/t 2s/t+O (Feet) (Ft3) (Ft3/Sec) (Ft3 /Sec) (Ft3 /Sec) 0 .00 0 0 .00 0 .00 0 .00 0 .37 263 0.20 8 .77 8 .97 0 .99 1,197 0 .88 39 .90 40.78 1.49 2 ,012 1.63 67 .07 68.69 1.99 2,867 2.51 95 .57 98.08 2 .59 3 ,944 3 .73 131.47 135.20 Storage Indication Curve Q; 2.50 ~---+----+-----+---+------;~---t-----1 iCL. -Q) Q) LL. 0 2.00 ~-----+----+-----+----W----+----+------1 :0 :::J 0 -Q) l .50 ------+----+------+----+------+----+-------; O> 0 .s::. ~ 1.00 ------+----+--.----+---+------+----+-------i 0 .00 20.00 40 .00 60 .00 80.00 l 00 .00 120 .00 140.00 2s/t+O (Cubic Feet Per Second) Inflow I Outflow Simulation 2-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.51 0.00 1 0.33 0.33 0.31 0.33 0.01 0.04 293.55 0.62 2 0.65 0.98 1.23 1.29 0.03 0.10 293.61 0.98 3 0.98 1.63 2.74 2.87 0.06 0.17 293.68 1.28 4 1.31 2.29 4.80 5.02 0.11 0.25 293.76 1.55 5 1.63 2.94 7.39 7.74 0.17 0.34 293.85 1.79 6 1.96 3.59 10.49 10.98 0.24 0.42 293.93 2.00 7 2.29 4.25 14.09 14.74 0.32 0.51 294.02 2.20 8 2.61 4.90 18.15 18.99 0.42 0.60 294.11 2.39 9 2.94 5.55 22.67 23.71 0.52 0.69 294.20 2.57 10 3.27 6.20 27.62 28.88 0.63 0.79 294.30 2.74 11 3.07 6.34 32.49 33.96 0.74 0.88 294.39 2.89 12 2.87 5.94 36.77 38.43 0.83 0.95 294.46 3.01 13 2.68 5.55 40.48 42.32 0.92 1.02 294.53 3.12 14 2.48 5.16 43.61 45.64 1.01 1.08 294.59 3.22 15 2.29 4.77 46.22 48.39 1.09 1.14 294.65 3.29 16 2.09 4.38 48.31 50.60 1.14 1.18 294.69 3.35 17 1.90 3.99 49.92 52.30 1.19 1.21 294.72 3.39 18 1.70 3.60 51.07 53.52 1.22 1.23 294.74 3.42 19 1.51 3.21 51.79 54.28 1.24 1.24 294.75 3.44 20 1.31 2.82 52.10 54.61 1.25 1.25 294.76 3.45 21 1.11 2.42 52.03 54.53 1.25 1.25 294.76 3.45 22 0.92 2.03 51.59 54.06 1.24 1.24 294.75 3.44 23 0.72 1.64 50.80 53.23 1.21 1.23 294.74 3.42 24 0.53 1.25 49.69 52.05 1.18 1.20 294.71 3.39 25 0.33 0.86 48.26 50.55 1.14 1.18 294.69 3.35 26 0.14 0.47 46.54 48.73 1.09 1.14 294.65 3.30 27 0.00 0.14 44.60 46.68 1.04 1.10 294.61 3.24 28 0.00 0.00 42.63 44.60 0.98 1.07 294.58 3.19 29 0.00 0.00 40.77 42.63 0.93 1.03 294.54 3.13 30 0.00 0.00 39.01 40.77 0.88 0.99 294.50 3.07 3 .50 3 .00 ~ g 2 .50 0 QI Cl) a; Q. 2 .00 li QI ~ 0 :0 ::::> 1.50 () .._, ~ 0 ~ 1.00 0 0 .50 0 .00 0 Inflow/Outflow Simulation 2-Year Storm Event , , , , , • , , , , 5 Pre----- Developme nt Hydrograph .... , ... 10 .... .... .... .... ... ... ... ... ... 15 20 Time (Minutes) Post -Post - Developme Developme nt Outflow nt O utflow Hydr ograph With Without Det ention Detention 25 30 -• -• -• Post - Develo pme nt "Free- Flow · Inflow I Outflow Simulation 5-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.51 0.00 1 0.48 0.48 0.46 0.48 0.01 0.05 293.56 0.71 2 0.97 1.45 1.83 1.91 0.04 0.13 293.64 1.12 3 1.45 2.42 4.05 4.24 0.10 0.22 293.73 1.46 4 1.93 3.38 7.10 7.44 0.17 0.33 293.84 1.76 5 2.42 4.35 10.95 11.46 0.25 0.43 293.94 2.03 6 2.90 5.32 15.55 16.27 0.36 0.54 294.05 2.27 7 3.38 6.29 20.88 21.84 0.48 0.66 294.17 2.50 8 3.87 7.25 26.91 28.14 0.61 0.78 294.29 2.72 9 4.35 8.22 33.61 35.14 0.76 0.90 294.41 2.92 10 4.84 9.19 40.93 42.80 0.94 1.03 294.54 3.13 11 4.55 9.38 48.04 50.31 1.14 1.17 294.68 3.34 12 4.26 8.80 54.22 56.84 1.31 1.29 294.80 3.51 13 3.97 8.22 59.52 62.44 1.46 1.39 294.90 3.63 14 3.68 7.64 63.99 67.16 1.59 1.46 294.97 3.74 15 3.39 7.07 67.66 71.05 1.70 1.53 295.04 3.82 16 3.10 6.49 70.56 74.14 1.79 1.59 295.10 3.89 17 2.81 5.91 72.74 76.46 1.86 1.63 295.14 3.94 18 2.52 5.33 74.25 78.07 1.91 1.66 295.17 3.97 19 2.23 4.75 75.12 79.00 1.94 1.67 295.18 3.99 20 1.94 4.17 75.39 79.29 1.95 1.68 295.19 4.00 21 1.65 3.59 75.11 78.98 1.94 1.67 295.18 3.99 22 1.36 3.01 74.30 78.12 1.91 1.66 295.17 3.98 23 1.07 2.43 72.99 76.73 1.87 1.63 295.14 3.95 24 0.78 1.85 71.21 74.84 1.81 1.60 295.11 3.91 25 0.49 1.27 69.00 72.49 1.74 1.56 295.07 3.85 26 0.20 0.69 66.38 69.70 1.66 1.51 295.02 3.79 27 0.00 0.20 63.44 66.58 1.57 1.46 294.97 3.72 28 0.00 0.00 60.46 63.44 1.49 1.40 294.91 3.66 29 0.00 0.00 57.65 60.46 1.41 1.35 294.86 3.59 30 0.00 0.00 54.98 57.65 1.33 1.30 294.81 3.52 5 .00 4 .50 4 .00 ,.... 'O c 3 .50 0 0 Cl> (/) ... 3 .00 Cl> ICI.. -Cl> Cl> 2 .50 LL. 0 :.a :J 2 .00 () -~ 0 = 1.50 :J 0 l.00 0 .50 0.00 0 Inflow/Outflow Simulation 5-Year Storm Event I I I I , , I , , 5 Pre ----- De velopme nt Hydrog raph I I ' I ' 10 ' ' ' ' ' ' ' ' ' ' 15 Time (Minutes) Pos t - Developme nt Outflow Hydr ograph Without Detention ' ' 20 25 Post -................ De velopme nt Outflow With Detention 30 Post- De velo pme nt 'Free- Flow' Inflow I Outflow Simulation 10-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.51 0.00 1 0.54 0.54 0.52 0.54 0.01 0.06 293.57 0.74 2 1.08 1.62 2.04 2.14 0.05 0.14 293.65 1.16 3 1.62 2.70 4.53 4.74 0.11 0.24 293.75 1.52 4 2.16 3.78 7.93 8.31 0.19 0.35 293.86 1.83 5 2.70 4.86 12.23 12.80 0.28 0.46 293.97 2.10 6 3.24 5.94 17.37 18.17 0.40 0.58 294.09 2.36 7 3.78 7.02 23.33 24.39 0.53 0.71 294.22 2.59 8 4.32 8.10 30.07 31.43 0.68 0.83 294.34 2.82 9 4.86 9.18 37.55 39.25 0.85 0.97 294.48 3.03 10 5.40 10.26 45.67 47.81 1.07 1.13 294.64 3.28 11 5.08 10.48 53.57 56.15 1.29 1.28 294.79 3.49 12 4.75 9.83 60.42 63.40 1.49 1.40 294.91 3.66 13 4.43 9.18 66.30 69.61 1.66 1.51 295.02 3.79 14 4.11 8.54 71.21 74.84 1.81 1.60 295.11 3.91 15 3.78 7.89 75.22 79.10 1.94 1.68 295.19 4.00 16 3.46 7.24 78.38 82.46 2.04 1.73 295.24 4.06 17 3.14 6.60 80.74 84.97 2.12 1.78 295.29 4.11 18 2.81 5.95 82.35 86.69 2.17 1.80 295.31 4.15 19 2.49 5.30 83.25 87.65 2.20 1.82 295.33 4.17 20 2.17 4.66 83.50 87.91 2.21 1.82 295.33 4.17 21 1.84 4.01 83.12 87.51 2.19 1.82 295.33 4.16 22 1.52 3.36 82.15 86.48 2.16 1.80 295.31 4.14 23 1.20 2.72 80.64 84.87 2.12 1.77 295.28 4.11 24 0.87 2.07 78.61 82.71 2.05 1.74 295.25 4.07 25 0.55 1.42 76.09 80.03 1.97 1.69 295.20 4.01 26 0.23 0.78 73.12 76.87 1.87 1.64 295.15 3.95 27 0.00 0.23 69.81 73.35 1.77 1.57 295.08 3.87 28 0.00 0.00 66.49 69.81 1.66 1.51 295.02 3.79 29 0.00 0.00 63.35 66.49 1.57 1.45 294.96 3.72 30 0.00 0.00 60.38 63.35 1.49 1.40 294.91 3.65 1J c 0 6.00 5.00 g 4 .00 Cl) a; Q.. -; Q) ..... 3.00 0 :0 :J () ....... ~ 0 2 .00 ~ 0 1.00 0 .00 0 Inflow/Outflow Simulation 10-Year Storm Event I I 5 Pre-- Developme nt Hydrograph I I - I I - I • I - I I • I '\. 10 15 20 25 Time (Minutes) Post -Post--------· De velopme Developme nt Outflow nt Outflow Hydrograph With Without Detention Detention 30 Post - Developme nt "Free- Flow · Inflow I Outflow Simulation 25-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.51 0.00 1 0.62 0.62 0.59 0.62 0.01 0.06 293.57 0.77 2 1.24 1.87 2.35 2.46 0.06 0.16 293.67 1.22 3 1.87 3.11 5.21 5.46 0.12 0.27 293.78 1.59 4 2.49 4.35 9.14 9.56 0.21 0.39 293.90 1.92 5 3.11 5.60 14.08 14.73 0.32 0.51 294.02 2.20 6 3.73 6.84 20.01 20.92 0.46 0.64 294.15 2.47 7 4.35 8.08 26.87 28.09 0.61 0.77 294.28 2.72 8 4.97 9.33 34.63 36.19 0.78 0.92 294.43 2.95 9 5.60 10.57 43.20 45.20 1.00 1.08 294.59 3.20 10 6.22 11.81 52.48 55.01 1.26 1.26 294.77 3.46 11 5.84 12.06 61.51 64.55 1.52 1.42 294.93 3.68 12 5.47 11.32 69.32 72.83 1.75 1.57 295.08 3.86 13 5.10 10.57 75.97 79.90 1.97 1.69 295.20 4.01 14 4.73 9.83 81.51 85.79 2.14 1.79 295.30 4.13 15 4.36 9.08 86.02 90.59 2.29 1.87 295.38 4.22 16 3.98 8.34 89.55 94.36 2.40 1.93 295.44 4.29 17 3.61 7.59 92.18 97.15 2.49 1.98 295.49 4.34 18 3.24 6.85 93.94 99.03 2.54 2.01 295.52 4.37 19 2.87 6.11 94.89 100.05 2.58 2.02 295.53 4.39 20 2.49 5.36 95.08 100.25 2.58 2.03 295.54 4.40 21 2.12 4.62 94.57 99.70 2.57 2.02 295.53 4.39 22 1.75 3.87 93.39 98.44 2.52 2.00 295.51 4.36 23 1.38 3.13 91.58 96.52 2.47 1.97 295.48 4.33 24 1.01 2.38 89.19 93.97 2.39 1.92 295.43 4.28 25 0.63 1.64 86.24 90.83 2.29 1.87 295.38 4.22 26 0.26 0.89 82.76 87.13 2.18 1.81 295.32 4.16 27 0.00 0.26 78.90 83.02 2.06 1.74 295.25 4.08 28 0.00 0.00 75.03 78.90 1.94 1.67 295.18 3.99 29 0.00 0.00 71.39 75.03 1.82 1.60 295.11 3.91 30 0.00 0.00 67.98 71.39 1.71 1.54 295.05 3.83 7.00 6 .00 ,, g 5.00 0 Cl) (/) Qi Q.. 4.00 -; Cl) u.. 0 :0 ::::7 3.00 u -~ 0 =§ 2.00 0 1.00 0 .00 0 Inflow/Outflow Simulation 25-Year Storm Event I ' I I I I I • I I I I ' 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post ---------Post- Developme Developme Deve lopme Developme nt nt Outfl ow nt Outflow nt "Free- Hydrograph Hydrograph With Fl ow" Without Detention Detent ion Inflow I Outflow Simulation 50-Year Storm Event T i me Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 293 .51 0 .00 1 0 .70 0.70 0 .67 0 .70 0 .02 0.07 293 .58 0 .80 2 1 .41 2 .11 2.66 2.78 0 .06 0 .17 293 .68 1.27 3 2 .11 3 .52 5 .90 6.17 0.14 0 .29 293.80 1.66 4 2 .81 4 .92 10.34 10.82 0 .24 0.42 293 .93 1.99 5 3 .52 6 .33 15.94 16.67 0 .37 0 .55 294 .06 2 .29 6 4 .22 7 .74 22.64 23 .67 0 .52 0 .69 294.20 2.57 7 4 .92 9 .14 30.41 31 .78 0 .69 0.84 294.35 2.83 8 5 .63 10.55 39 .18 40.96 0 .89 0 .99 294.50 3 .08 9 6 .33 11 .96 48 .82 51 .14 1.16 1.19 294 .70 3 .36 10 7 .03 13.36 59 .28 62 .19 1.45 1.38 294 .89 3 .63 11 6 .61 13.65 69.41 72 .92 1.76 1 .57 295 .08 3 .86 12 6 .19 12.80 78 .15 82.22 2 .04 1 .73 295 .24 4.06 13 5 .77 11 .96 85 .56 90 .11 2.27 1.86 295 .37 4.21 14 5 .35 11 .12 91.74 96.68 2.47 1.97 295.48 4 .33 15 4 .93 10.28 96.73 102.01 2.64 2 .06 295.57 4.43 16 4 .51 9.43 100.61 106.16 2 .78 2 .13 295 .64 4 .50 17 4 .09 8 .59 103.44 109.20 2 .88 2 .18 295.69 4 .56 18 3.66 7 .75 105.31 111.19 2 .94 2 .21 295 .72 4.59 19 3 .24 6 .91 106.26 112 .21 2.98 2 .23 295.74 4 .61 20 2.82 6.06 106.36 112 .32 2 .98 2 .23 295.74 4 .61 21 2.40 5 .22 105.67 111 .58 2 .96 2 .22 295.73 4 .60 22 1.98 4 .38 104.24 110.05 2 .91 2 .19 295 .70 4 .57 23 1.56 3 .54 102 .11 107.78 2.83 2 .15 295.66 4 .53 24 1.14 2 .70 99.34 104.81 2 .73 2 .10 295 .61 4.48 25 0 .72 1.85 95.96 101 .20 2 .62 2 .04 295 .55 4 .41 26 0 .29 1.01 92 .02 96.98 2.48 1.97 295.48 4 .34 27 0.00 0 .29 87 .63 92.31 2 .34 1 .90 295.41 4 .25 28 0 .00 0 .00 83 .23 87 .63 2 .20 1 .82 295 .33 4 .16 29 0 .00 0.00 79.10 83 .23 2 .07 1.75 295 .26 4 .08 30 0 .00 0 .00 75 .22 79 .10 1.94 1.68 295 .19 4 .00 8 .00 7 .00 ...... 6 .00 "O c 0 0 CD en 5 .00 ... CD 0.. -CD CD 4.00 LL. 0 :0 :J u 3.00 ...., ~ 0 E :J 0 2 .00 l.00 0 .00 0 Inflow/Outflow Simulation 50-Year Storm Event , , , , • , , , , 5 Pre----- Developme nt Hydrograph , ' , 10 ... 15 ' ' Time (Minutes) Post- Developme nt Outflow Hydrograph Without Detention 20 25 Po st -.... -... Developme nt Outflow With Det ention 30 Post- Developme nt "Free- Fl ow" - Inflow I Outflow Simulation 100-Year Storm Event T ime Inflow 11 + 12 2s/t-O 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3 /Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 293 .51 0 .00 1 0 .79 0 .79 0.76 0.79 0.02 0.07 293 .58 0 .84 2 1.58 2 .37 2.99 3 .13 0 .07 0.18 293 .69 1.32 3 2 .37 3 .96 6.63 6.95 0 .16 0 .31 293.82 1.72 4 3.17 5 .54 11 .63 12.17 0 .27 0.45 293 .96 2.07 5 3 .96 7 .12 17.93 18.75 0.41 0 .59 294 .10 2.38 6 4 .75 8 .70 25.48 26.64 0.58 0 .75 294.26 2.67 7 5 .54 10.29 34 .22 35 .76 0 .77 0 .91 294.42 2 .94 8 6 .33 11 .87 44 .04 46 .08 1.02 1.09 294 .60 3.23 9 7 .12 13.45 . 54 .83 57.49 1.33 1.30 294.81 3 .52 10 7 .91 15.03 66.54 69.87 1.66 1.51 295.02 3 .80 11 7.44 15.35 77 .84 81 .89 2 .03 1.72 295 .23 4.05 12 6 .97 14.40 87 .57 92.24 2 .34 1.90 295.41 4.25 13 6.49 13.46 95 .81 101.03 2 .61 2 .04 295 .55 4.41 14 6 .02 12.51 102 .62 108.31 2 .85 2 .16 295 .67 4.54 15 5 .54 11 .56 108.09 114.18 3 .04 2 .26 295 .77 4 .64 16 5.07 10.61 112 .33 118.71 3 .19 2 .33 295.84 4.72 17 4 .60 9.67 115.40 121.99 3 .30 2 .39 295 .90 4.77 18 4 .12 8 .72 117.38 124.12 3.37 2.42 295 .93 4.80 19 3 .65 7 .77 118.35 125.15 3.40 2.44 295 .95 4 .82 20 3 .17 6 .82 118.37 125.17 3.40 2.44 295 .95 4.82 21 2 .70 5 .88 1 17 .50 124.24 3 .37 2.42 295 .93 4.80 22 2 .23 4.93 115 .80 122.43 3 .31 2 .39 295 .90 4 .77 23 1.75 3 .98 113.33 119 .78 3 .23 2 .35 295 .86 4.73 24 1.28 3 .03 110.14 116.36 3.11 2 .30 295.81 4.68 25 0 .81 2.08 106.27 112.22 2 .98 2 .23 295 .74 4.61 26 0 .33 1.14 101 .77 107.40 2.82 2 .15 295 .66 4 .52 27 0 .00 0 .33 96 .81 102.10 2 .64 2 .06 295 .57 4.43 28 0 .00 0 .00 91.86 96 .81 2.47 1.97 295.48 4 .33 29 0 .00 0.00 87 .21 91 .86 2 .33 1.89 295.40 4 .24 30 0 .00 0 .00 82 .83 87 .21 2 .19 1.81 295.32 4 .16 Inflow/Outflow Simulation 100-Year Storm Event 8.00 I ' I • ' 7.00 I ' I • ' ....... 6 .00 I "O c I ' 0 • () I ' Q) en 5.00 ... Q) • ' ~ I .. -' Q) I Q) 4 .00 .. ...... ' () I :0 ::;:, u 3.00 ....., ~ 0 ;: ::;:, 0 2.00 1.00 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post---------Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt 'Free- Hydrograph Hydrograph With Flow' Without Detention Detention Inflow/Outflow Simulation 2-Year Storm Event 1.2 0 ...... "O c 0 0 QI 1.00 (/) ... QI Q. -QI QI 0.80 ..... 0 :0 ::J () ...... ~ 0.60 0 ~ ::J 0 0 .40 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hy drograph ----Total Post-Development Hydr ograph Inflow/Outflow Simulation 5 -Year Storm Event 2.50 2.00 ........ "C c 0 0 G> Cl) 1.50 -G> ~ -G> G> LL. 0 :0 :I u 1.00 ........ ~ 0 == :I 0 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Post-Development Hydrograph Inflow/Outflow Simulation 10-Year Storm Event 2.50 2.00 ....... "O c 0 0 Cl) Cl) 1.50 ... Cl) Q.. -Cl) Cl) LI. 0 :0 :l u 1.00 ....... ~ 0 = :l 0 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre -D evelopment Hydrograph ----To t a l Post-Development Hyd rograph Inflow/Outflow Simulation 25-Year Storm Event 3.00 2.5 0 ..... "O c 0 2 .00 0 G> V> ... G> 0.. -G> G> 1.50 u.. 0 :0 :J u ......, ~ 0 1.00 i: :J 0 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Post-Development Hydrograph Inflow/Outflow Simulation 50-Year Storm Event 3.50 3 .00 ...... 2 .50 'U c 0 0 CD Cl) ... CD 2 .00 0... -CD CD iA.. 0 :0 :J 1.50 u -~ 0 = :J 0 1.00 0 .50 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Post-Development Hyd rograph Inflow/Outflow Simulation 100-Yeor Storm Event 4.00 3 .50 3.00 ........ ,, c: 0 0 Cl> 2 .50 (/) .... Cl> Q. -Cl> Cl> 2 .00 ...... 0 :0 ::J 0 .._, ~ l.50 0 E ::J 0 l .00 0.50 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-Devel opment Hydrograph ----Tot a l Post-De velopment Hyd rograph Figure XII Development Permit City of College Station, Texas Site Legal Description: Lo T 7. fJ LOC /c I / k-F 0 A YJ 011) U rJ I / Site Owner: 5 1 -fV\ fl rJ !CA tU\ N Address : 2/ 9 f14 N Uc L Y) fl I v t / <. 5, Tl, Telephone : (4:09) 6 9 ]-o 55 I -, 7 f11-o ' Architect/ Engineer: G It 'fl YI { T r: f'/ (; 1 N t: ( tl 1 rv l Address : f11-4 CAflf(ll Ol((t:-f ft.lv'f [VITC: iot /j M~tl I / Telephone No :( 4-ti~) f?+c; -Lh sg 1'Y. Address : ------------Te 1 e phone No : _________ _ Date Application Filed: _______ _ Approved : ----------- Application is hereby made for the following development specific waterway alterations : /Application Fee ~h ~ 0 -pa._lJ ~ Signed Certifications 6 ~ Drainage an p a , with supporting Drainage Report two (2) copies each. Sit _ ~· tion Plans, with supporting Drainage Report two .(2) copies each . ~-············· .. 1-. I,~;b_~~~~~~~~~--___) design engineer, hereby acknowledge or affirm that: ',..~ ...... , · .. •• <; s s· .... ······· '.J:' The inform ~lf-~°ai 7"'C~clusions 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 of approval of this permit application, I agree to construct the improvements proposed in this application according to these documents and the requirements of Chapter 13 of the College Station City Code. y____ ff L_ Property Owner(s) Contractor .. .. Figure XII Continued CERTIFICATIONS : (for proposed alterations within designated flood hazard areas .) A. I , certify that an y nonresidential structure on or proposed to be on this site as part of this application is designated t o prevent damage to the structure or its contents as a result of flooding from the 100 year storm . Engineer Date C . I , certify that the alterations or development covered by this permit shall not diminish the flood-carrying 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 floodways and of floodway fringes . Engineer Date 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 Date Conditions or comments as part of approval : ------------------- In accordance with Chapter 13 of the Code of Ordinances of the City of College Station, measures shall be taken to insure that debris from construction, erosion, and sedimentation shall not be deposited in city streets, or existing drainage facilities . I hereby grant this permit for development. All development shall be in accordance with the plans and specifications submitted to and approved by the City Engineer for the above named project. All of the applicable codes and ordinances of the City of College Station shall apply . XI. Drainage Plan Submittal Requirements A . Review Process The development permitting process requires an approved drainage plan for any subdivision platting activity, any replatting process , any development requiring site plan review only , and any development on existing commercial , high-density , or industrial lot or tract. The review process for any drainage plan involves a two-or three-step process. The preliminary drainage conference with the Administrator and a final drainage plan is required for all development permits . If desired, a preliminary drainage plan may be submitted. B. General Drainage Plan Requirements The submitted drainage plan must satisfy the requirements of the City of College Station Stormwater Management Ordinance , the requirements of the City of College Station Drainage Policy and Design Standards , and the specific requirements of this section of the Standards. C. Preliminary Drainage Conference 1. The drainage design concept for the proposed development shall be discussed with the Administrator prior to the development of any specific design or plan preparation. The parties representing the proposed development shall obtain all resources , plans , and references necessary to discuss the items below. The conference shall address the following information relative to the proposed development. a . General Location (1) Local streets , within and adjacent to the development (2) Primary and secondary drainageways and drainage facilities in the vicinity (3) Names of surrounding developments b. Property Description (1) Acreage (2) Type of land cover (both existing and proposed ) (3) Name of Owner and type of development (4) Current zoning status and proposed change, if any c. Primary Drainage Basin Description (1) Basin drainage characteristics (2) Related previous drainage studies l (3) Flood Insurance Maps d. Secondary Drainage Basin Description -Discussion of onsite and offsite drainage flow patterns and anticipated impact on existing and ultimate development e . Drainage Facility Design (1) General Concept a.) Discussion of concept and typical drainage patterns (This shall include the delineation of the pathways for conducting the discharges from the site to the Primary Drainage System) b.) Discussion of compliance with offsite runoff considerations c.) Discussion of the content of tables , charts , figures , or drawings to be presented in the report (2) Specific Details a.) Discussions of drainage and erosion problems encountered and proposed solutions at specific design points both onsite and offsite b.) Discussion of detention/retention storage and outlet design , if any c.) Discussion of maintenance access and aspects of the design d.) Discussion of the areas to be set aside as drainage easement and right- of-way f. References -Reference all criteria , master plans , and technical information used in support of concept 2. Upon completion of the preliminary drainage conference , the Administrator may require the submission of a preliminary drainage report and plans. Tnese shall be prepared along the lines of the requirements of the Final Drainage Report and Drawings. D. Final Drainage Report and Drawings 1. The purpose of the Final Drainage Report is to identify and define conceptual solutions to the problems which may occur onsite and offsite as a result of the development. All reports shall be typed on 8-112" x 11" paper and bound together. The report shall include a cover letter presenting the proposed design for review and shall be prepared by a Registered Professional Engineer licensed in Texas. The report shall contain a certification sheet as follows: "I hereby certify that this report (plan) for the drainage design of (Name of Development) was prepared by me (or under my supervision) 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. ~~~~~~~~~~ (Affix Seal) 2 . Report Contents 3 The Final Drainage Report shall be in accordance with the following outline and contain the applicable information listed: a. General Location and Description (1) Location a.) Loc a l streets within and adjace nt to the dev e lopment b.) Primary Drainage System drainageways and facilit ies c .) Names of surrounding developments (2) Description of Property a .) Acreage b.) Land cover c .) Primary and Secondary System drainageways within the property d.) General project description b . Drainage Basins and Sub-Basins (1) Primary Basin Description a.) Reference to Primary Drain age System planning studies such as flood hazard delineation reports and flood insurance rate maps b .) Primary Basin drainage char acteristics (2) Secondary Drainage Basin Description -Discussion of offsite drainage flow patterns and impact of development on existing and proposed pathways to Primary Drainage System c . Drainage Design Criteria (1) Regulations -Discussion of the optional criteria selected or the deviation from the Standards , if any · (2) Development Criteria Reference and Constraints a.) Discussion of previous drainage studies for the site in question that influence or are influenced by the drainage design and how the plan will affect drainage design for the site b.) Discussion of the drainage impact of site constraints such as streets , existing structures , and development or site plan (3) Hydrological Criteria a.) Identify design rainfall b .) Identify runoff calculation method c.) Identify detention discharge and storage calculation method , if any d.) Identify design storm recurrence intervals e.) Discussion and justification of other criteria or calculation methods used that are not presented in or referenced by the Standards (4) Hydraulic Criteria a.) Identify various capacity references b.) Identify detention/retention outlet type, if any c .) Discussion of other drainage facility design criteria used that are not presented in the Standards d. Drainage Facility Design (1) General Concept a.) Discussion of concept and typical drainage patterns b.) Discussion of compliance with offsite runoff considerations c .) Discussion of the content of tables , charts , figures , or drawings presented in the report d.) Discussion of anticipated and proposed drainage patterns (2) Specific Details a.) Discussion of drainage problems encountered and solutions at specific design points b.) Discussion of detention storage and outlet design, if any c.) Discussion of maintenance access and aspects of the design e. Conclusions (1) Compliance with standards of the City of College Station Drainage Policy and Design Standards 5 (2) Effectiveness of drainage design to control damage from stormwater flows (3) Explanation of the effectiveness of existing and proposed improvements with regard to controlling the discharges of the 100 year storm with ultimate development conditions of the secondary system basins affected by the proposed development f. References -Reference all criteria and technical information used g. Appendices (Where Applicable) (1) Hydrologic Computations a.) Land use assumptions regarding adjacent properties b .) Minor and major storm rnnoff at specific design points c.) Historic and fully developed runoff computations at specific design points d.) Hydrographs at critical design points (2) Hydraulic Computations a.) Culvert capacities b.) Storm sewer capacity c.) Street capacity d.) Storm inlet capacity including inlet control rating at connection to storm sewer e.) Open channel design f.) Detention area/volume capacity and oucier capacity calculations E. Final Drainage Report Drawing Contents 1. Sheet #1 -General Location Map a. Depicts drainage flows entering and leaving the development site b. Identifies major construction along path of drainage c. Illustrates general drainage flow within entire basin d. Is drawn at a scale of 1" = 500' to 1" = 2000' 2. Sheet #2 -Floodplain Information a . Copies of existing City of College Station 100-year floodplain maps showing the location of the subject development 3 . Sheet #3 -Drainage Plan -Map (s) of the proposed development at a scale of 1" = 20' to 1" = 200' on a 24" x 36" drawing shall be included. The plan shall show the following: a. Existing and proposed contours at 2-feet maximum intervals b . Property lines and easements with purposes noted c. Streets d. Existing drainage facilities, roadside ditches , drainageways, gutter flow directions , and culverts (All pertinent information such as material, size, shape, slope , and location shall also be included) e. Overall drainage area boundary and drainage sub-area boundaries f. Proposed type of street flow , roadside ditch , and/or gutter flow directions g . Proposed storm sewers and open drainageways, including inlets , manholes, culverts, and other appurtenances. h . Proposed outfall point for runoff from the developed area and facilities to convey flows along the proposed pathways to the final outfall points in the primary drainage system without damage to downstream properties , or exceeding the capacities of the receiving facilities as defined in these standards. i. Routing and accumulation of flows at various critical points for the minor storm runoff. J. Path(s) chosen for computation of time-of-concentration k. Details of detention/retention storage facilities and outlet works l. Location and elevations of all defined floodplains affecting the property m . Location and elevations of all existing and proposed utilities affected by or affecting the drainage design n. Routing of offsite drainage flow through the development F. Construction Drawings and Specifications 1. Where drainage improvements are to be constructed in accordance with the approved Final Drainage Report, the construction plans (on 24" x 36" sheets) and specifications shall be submitted for review and approval prior to construction . The plans and specifications for the drainage improvements will include: a. Storm sewers, inlets, and outlets 7 . . b . Culverts , end sections , and inlet /outlet protection c . Channels , ditches , and swales d . Erosion control facilities e. Detention pond grading , pilot channels , o utlets , and la ndsca ping f. Other drainage related structures and fac ilities g. Maintenance access considerations h. Finished floor elevations of ad j acent buildings i. Existing and Ultimate 100-year water surface elevations j. Engineer certifications k . Approval by the City 2. The information required for the drawings and spe c ifications shall be in accordance with sound engineering principles , these Standards , and the City requirements for subdivision designs . Construction documents shall include geometric , dimensional , structural , foundation , bedding , hy draulic , landscaping , and other details as needed to construct the storm drainage fac ility. The approved Final Drainage Plan shall be included as part of the construction documents for all facilities affected by the drainage plan . G . "As-Built Drawings" .- As constructed finished plans (" As -Builts ") for all public improvements shall be attested to by a professional engineer registered in Texas and submitted to the C ity before me City will accept the improvements. The construction d raw in gs are acceptable if they remain true afte r construction and are attested to by a registered e ngineer to represent "As-Built" conditions consistent with the intent of the approved plan . XII. Development Permitting Process The City of College Station Stormwater Management Ordinance requires the acquisition of a development permit prior to beginning "development" activities defined within the Ordinance. A blank Development Application Form (for areas within and outside established flood hazard areas is included in the section as Figure XII. CITY OF COLLEGE STATION Post Office Box 9960 1101 Texas Avenue November 1, 1994 Garrett Engineering 4444 Carter Creek Blvd ., Suite 108 Bryan, TX 77802 Attn : Earl Havel RE: KFO Mini Storage Facility Drainage Report Dear Earl , ' College Station.Texas 77842-0960 (409) 764-3500 I have completed my review of the drainage plan and report for this project, and am returning it with comments for correction . In particular, we have a policy of not allowing detention for private facilities within the public right of way . I know that an exception was made for your Pershing Park project, but this site is different with the possibility of sidewalk and ADA ramps being installed in the future . It is my understanding that to place the detention basin as shown on your plans , that a maintenance agreement would have to be reached with the City, which would include a variance to the use of the right of way for your basin . Once you have looked these comments over, it may help to arrange a meeting with myself, Mark Smith and Kent Laza if you still wish to pursue this design . #!' BrettM!~ Project Manager cc : Ke t Laza, City Engineer eronica Morgan, Assistant City Engineer Shirley Volk, Development Coordinator Ho me of Texas A&M University CITY OF COLLEGE STATION Post Office Box 9960 1101 Texas Avenue College Station, Texas 77842-9960 October 11, 1994 Garrett Engineering 4444 Carter Creek Blvd., Suite 108 Bryan, TX 77802 Attn : Earl Havel RE: KFO Mini Storage Facility Improvement Plans Dear Earl, ( 409) 764-3500 We have received and approved the Fire Hydrant plans for this site, however there wei-e only 5 sets submitted, so you need to get 5 more to us for approval stamping . Once we receive and stamp all the plans, we will provide you with your sets . We have also approved your Erosion Control plans , and therefore need 10 sets for approval stamping. We received an application for a Drainage Development Permit, however no updated calculations were provided . According to my file notes, I spoke with you on April 15th of this year, and you advised me that the site was changing, and I need not review the report which had been submitted. Upon my review of the erosion control plans , I did notice that the plan has changed somewhat, so a new and/or revised report is required . Please get the plans and reports mentioned above to me as soon as possible and remember to call me should you have any questions . ~ BrettM!tf Project Manager cc : Veronica Morgan, Assistant City Engineer Shirley Volk, Development Coordinator Home of Texas A&M University ~·~ ( ~!!a~.~:.96~0LLEGE ~~~::!~~ ~ College Station, Texas 77842-0960 November 1, 1994 Garrett Engineering 4444 Carter Creek Blvd., Suite 108 Bryan, TX 77802 Attn : Earl Havel RE: . }0f0 Mini Storage Facility VDrainage Report Dear Earl , ' (409) 764-3500 I have completed my review of the drain age pl an and report for this project, and am return ing it with comments for correction. In particular, we have a policy of not allo w in g detention for private facilities within the public right of way. I know that an ex ception was made for your Pershing Park project, but this site is different with the possibility of sidewalk and ADA ramps being installed in the future . It is my understanding that to place th e detention basin as shown on your plans , that a maintenance agreement would have to be reached with the City, which would include a variance to the use of the right of way for your basin . Once you have looked these comments over, it may help to arrange a meeting with myself, Mark Smith and Kent Laza if you still wish to pursue this design . Al' Brett M!rf:- Project Manager cc : Kent Laza, City Engineer Veronica Morgan, Assistant City Engineer Shirley Volk, Development Coordinator Ho rne of Texas A&M Un iversity DRAINAGE COMPUTATIONS For Lot 5 , Block 1 K.F .O. Addition College Station, Brazos County, Texas Prepared By : Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 .t• r 'RECE\\JED ~\ O\J ' 8 \991\ DRAINAGE COMPUTATIONS For Lot 5, Block 1, K.F.O. Addition College Station, Brazos County, Texas * November, 1994 * SUMMARY The project is situated adjacent to Manuel Drive and Cornell Street in College Station, Brazos County, Texas. The Lot 5, Block 1 K.F.O. addition consists of 1 lot which is to have a mini-storage complex placed on it The total drainage area tributary to the project is 0.78 acres. The pre-development run-off coefficient was estimated to be 0.40, while talcing into account the proposed site improvements would result in a post- development run-off coefficient of 0 .83. A detention facility will be constructed along Cornell street and Manuel Drive as designated on the Site & Grading plan .. The detention pond is designed to facilitate up to and including the 100-year storm event, and discharge at a rate less than the current pre-development peak discharge rate. The detention pond will intercept, store and meter run-off from 0.68 acres of the project. The run-off generated on the remaining 0.10 acres will "free-flow" across the project site unmetered off the property . From the computations on page 1, based on the total tributary drainage area of the project being estimated at 0 .78 acres, the pre-development run-off coefficient being assumed at 0.40, and a minimum time of concentration of 10 minutes, the relative pre-development peak discharge rate ("Q") was determined. The Rational Method was utilized to compute the estimated peak pre-development discharge rates. The equation that represents the Rational Method is as follows: Q = CIA . "Q" is the peak discharge rate in cubic feet per second, "C" is the run-off coefficient, assumed to be 0.40 in the pre-development condition , "I" is the storm intensity in inches per hour, and" A" is the area of the drainage basin in acres . From the computations on page 2, based on the tributary area of 0.78 acres, the post-development run-off coefficient being assumed at 0 .83, and a minimum time of concentration of 10 minutes, the relative pre- development peak discharge rate ("Q") was determined assuming the same minimum time of concentration of 10 minutes. The Rational Method was again utilized to compute the estimated peak post-development discharge rates. The equation that represents the Rational Method is as follows: Q = CIA, where; "Q" is the peak discharge rate in cubic feet per second. "C" is the run-off coefficient, in the post-development condition "C" is assumed to be 0.83, "I" is the storm intensity in inches per hour and "A" is the area of the drainage basin in acres . The comparison between the peak pre-development discharge rate and post-development discharge rate is included as an aid to the designer to establish a preliminary "target''. for the necessary volume in the proposed detention facility. This preliminary estimate is found by simply determining the volume generated from the difference between the pre-development and post-development hydrographs (see pages 9-11 for pre- development and post-development hydrographs). Please note that the post-development hydrograph shown on these same graphs assumes no detention . Page 3 and page 4 provide computations that determine the post-development run-off that is not routed through the detention facility ("free-flow") and post-development run-off that is routed through the detention facility. Page 5 and page 6 are tabulations of the pre-development hydrograph and the post-development hydrograph based on the computations performed on page 1 and page 2. The post-development hydrograph assumes no detention to facilitate direct comparison in the pre-and post-development conditions. Page 7 and page 8 are tabulations of the post-development hydrograph for run-off directed through the detention facility and the post-development hydrograph for "free-flow" from the project site. Computations on page 4 determine the actual peak post-development "inflow" rate supplied to the proposed detention facility. From this "inflow" rate and the time of concentration (10 minutes minimum), a hydrograph as tabulated on page 8 can be derived. The hydrograph is triangular in shape and is based on the standard SCS unit hydrograph with time to peak set equal to the time of concentration and the total time base set at 3.00 times the time of concentration. Please note that a 30 minute total storm event duration was utilized exclusively throughout this report due totally to the small physical size of the project Having derived the preliminary volume requirements and "allowable peak" discharge rate, it is now possible to design the final detention facility and outlet control structure. Page 12 presents a tabulation and a depth versus volume graph of the detention facility. The maximum depth of the pond was set at 3.09' (top retaining wall less flow line "out" of outlet control structure: 296.68' -293.59' = 3 .09'). Page 13 supplies a tabulation and a rating curve for the proposed outlet control structure. A rectangular weir was decided upon due to depth verses discharge ratio characteristics associated with the anticipated shallow headwater depth (maximum of 3 .09') and the fixed weir width of 0.25' (3"). The equation used to determine discharge was Q = CLH3/2 where "Q" is the discharge rate in cubic feet per second. "C" is the coefficient of discharge, in this case assumed to be set at 3 .000. "L" is the width of the weir in feet, in this case assumed to be set at 0.25'. "H" is the headwater depth in feet (ranges from O' to a maximum of 3.09'). Page 14 presents a tabulation of the relationship between discharge from the detention facility and the dimensionless quantity 2S/t-O. Also presented is a Storage Indication Curve for the detention facility based on the aforementioned physical characteristics of the detention pond, storage volume, inflow hydrograph, and rating curve for the outlet structure. The storage indication curve as shown on page 12 is a graphical solution to the equation presented in the "Drainaae Policy And Desian Standards" as follows : 2s1 (I1+12) + (----------------01) = dt 2s2 (-----------------+ 02) dt Page 15 through page 26 present simulations of the 2, 5, 10, 25, 50, and 100 year storm events. The first page of each storm simulation represents the tabulated data for the storm event. The maximum depth achieved in the detention pond during each simulation is shown below as is the time period during which this maximum depth occurs after the beginning of the storm event. The calculated peak discharge rate corresponding to this depth over same period is also shown below. Additionally, the maximum water surface elevation achieved during each event and the maximum peak discharge during each event are listed below. The second page of each storm simulation represents the pre-development hydrograph, the post-development hydrograph (with no detention), the post-development hydrograph as routed through the detention pond , and post-development "free-flow" hydrograph for each storm event Storm Max Depth (Year) (Ft) 2-year 1.77 5-year 2.02 IO-year 2.19 25-year 2.39 50-year 2.63 100-year2.71 Time Period (Min) 20-22 20-22 20-21 20-22 20-21 20-21 Max Discharge Max Elev (CFS) (Ft MSL) 1.77 295.36 2.16 295.61 2.43 295.78 2.78 295.98 3.20 296.22 3.35 296.30 Max Velocity (Ft/Sec) 3.99 4.27 4.44 4.64 4 .86 4.94 Page 27 through page 32 provide total inflow/outflow hydrographs for the 2, 5, 10, 25 , 50 and 100-year pre- development and post-development storm events . It can be determined from these same hydrographs that the post-development peak discharge rates have been minutely decreased from those peak pre-development discharge rates due to the incorporation of the detention facility in the post-development condition. Total post-development peak discharge rates from the detention pond outlet control structure and project site are kept less than the pre-development peak discharge rates due to the incorporation of the proposed detention facilities . Subsequent peak post-development discharge velocities projected to be within manageable limits . Determine Total Pre-Development Peak Storm Water Dischar e Rates Tributary Area ("A"): 0 .78 Acres Pervious Area : 0.78 Acres Impervious Area: 0.00 Acres Run-Off Coefficient ("Cwt"): 0.40 Time Of Concentration ("T/c"): Woodlands: Low Elevation: High Elevation: Distance (Feet): Slope (% Grade): Velocity ("Vw"): Time : Pastures: Low Elevation: High Elevation : Distance (Feet): Slope (% Grade): Velocity ("Vp"): Time : Pavements: Low Elevation : High Elevation : Distance (Feet): Slope (% Grade): Velocity ("Vpave"): Time : Total Travel Time: Hourly Intensity Rates ("I"): 2-Year: 6. 3 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11 .15 100-Year: 11 .64 Peak Discharge Rate ("Q"): 2-Year: 1.99 5-Year: 2.42 10-Year: 2.72 25-Year: 3 .10 50-Year: 3.51 100-Year: 3.66 C= 0.40 C= 0 .98 0.00 0.00 0.00 0.00 0 .00 Feet I Second 0.00 Minutes 0.00 0.00 0.00 0.00 0.00 Feet I Second 0 .00 Minutes 0.00 0.00 0.00 0.00 0 .00 Feet I Second 0.00 Minutes 10.00 Minutes Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post-development Peak Storm Water Dischar e No Detention) Tributary Area ("A"): 0.78 Acres Pervious Area : 0.20 Acres Impervious Area : 0.58 Acres Run-Off Coefficient ("Cwt"): 0.83 Time Of Concentration ("T/c"): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year : 7.69 10-Year: 8 .63 25-Year : 9.86 50-Year : 11 .15 100-Year: 11.64 C= 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Peak Discharge Rate ("Q"): 2-Year: 4.14 Cubic Feet I Second 5-Year: 5.03 Cubic Feet I Second 10-Year: 5.65 Cubic Feet I Second 25-Year: 6.45 Cubic Feet I Second 50-Year: 7.29 Cubic Feet I Second 100-Year: 7.61 Cubic Feet I Second Comparison Of Predevelopment A nd Post-develo ment Peak Discharge Rates Predevelopment Post-Development Increase 2-Year: 1.99 Ft3/sec 4.14 Ft3/sec 2.15 Ft3/sec 5-Year: 2.42 Ft3/sec 5.03 Ft3/sec 2.61 Ft3/sec 10-Year: 2. 72 Ft3/sec 5.65 Ft3/sec 2 .93 Ft3/sec 25-Year: 3.1 O Ft3/sec 6.45 Ft3/sec 3.35 Ft3/sec 50-Year: 3.51 Ft3/sec 7 .29 Ft3/sec 3.78 Ft3/sec 100-Year: 3.66 Ft3/sec 7.61 Ft3/sec 3.95 Ft3/sec Prelimin ary Determination Of Detenti on Pond Volume 2-Year: 2.15 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 1,931 Cubic Feet 5-Year: 2 .61 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 2,348 Cubic Feet 10-Year: 2 .93 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 2,636 Cubic Feet 25-Year: 3 .35 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 3,011 Cubic Feet 50-Year: 3 .78 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 3,403 Cubic Feet 100-Year: 3 .95 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 3,553 Cubic Feet Determi,pe Post-Development 11 Free-Flow 11 Peak Storm Water Dischar e ' Tributary Area ("A"): 0 .10 Acres Pervious Area : 0.08 Acres Impervious Area: 0 .02 Acres Run-Off Coefficient ("Cwt"): 0.52 Time Of Concentration ("T/c"): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11.15 100-Year: 11.64 Peak Discharge Rate ("Q"): 2-Year: 0.33 5-Year: 0.40 10-Year: 0.45 25-Year: 0.51 50-Year: 0.58 100-Year: 0 .61 c = 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determin~ Post-Development Flow Into Detenti'on Pond Tributary Area ("A"): 0.68 Acres Pervious Area : 0.12 Acres Impervious Area : 0.56 Acres Run-Off Coefficient ("Cwt"): 0 .88 Time Of Concentration ("T/c"): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6 .33 5-Year: 7.69 10-Year: 8 .63 25-Year: 9 .86 50-Year: 11.15 100-Year: 11.64 Peak Discharge Rate ("Q"): 2-Year: 3.81 5-Year: 4 .63 10-Year: 5 .20 25-Year: 5.93 50-Year: 6.71 100-Year: 7 .00 c = 0.40 C= 0 .98 Inches I Hour Inches I Hou r Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Pre-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year {Minutes} Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.20 0.24 0.27 0.31 0.35 0.37 2 0.40 0.48 0.54 0.62 0.70 0.73 3 0.60 0.73 0.81 0.93 1.05 1.10 4 0.80 0.97 1.09 1.24 1.40 1.46 5 1.00 1.21 1.36 1.55 1.75 1.83 6 1.19 1.45 1.63 1.86 2.10 2.20 7 1.39 1.69 1.90 2.17 2.45 2.56 8 1.59 1.94 2.17 2.48 2.81 2.93 9 1.79 2.18 2.44 2.79 3.16 3.30 Peak=> r 10 1.99' 2.42 2.72 3.10 3.51 µ 3.66 11 1.89 2.30 2.58 2.95 3.33 3.48 12 1.79 2.18 2.44 2.79 3.16 3.30 13 1.69 2.06 2.31 2.64 2.98 3.11 14 1.59 1.94 2.17 2.48 2.81 2.93 15 1.49 1.82 2.04 2.33 2.63 2.75 16 1.39 1.69 1.90 2.17 2.45 2.56 17 1.29 1.57 1.77 2.02 2.28 2.38 18 1.19 1.45 1.63 1.86 2.10 2.20 19 1.09 1.33 1.49 1.71 1.93 2.01 20 1.00 1.21 1.36 1.55 1.75 1.83 21 0.90 1.09 1.22 1.40 1.58 1.65 22 0.80 0.97 1.09 1.24 1.40 1.46 23 0.70 0.85 0.95 1.09 1.23 1.28 24 0.60 0.73 0.81 0.93 1.05 1.10 25 0.50 0.61 0.68 0.78 0.88 0.92 26 0.40 0.48 0.54 0.62 0.70 0.73 27 0.30 0.36 0.41 0.47 0.53 0.55 28 0.20 0.24 0.27 0.31 0.35 0.37 29 0.10 0.12 0.14 0.16 0.18 0.18 30 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.41 0.50 0.56 0.64 0.73 0.76 2 0.83 1.01 1.13 1.29 1.46 1.52 3 1.24 1.51 1.69 1.93 2.19 2.28 4 1.65 2.01 2.26 2.58 2.92 3.04 5 2.07 2.51 2.82 3.22 3.64 3.80 6 2.48 3.02 3.39 3.87 4.37 4.57 7 2.90 3.52 3.95 4.51 5.10 5.33 8 3.31 4.02 4.52 5.16 5.83 6.09 9 3.72 4.53 5.08 5.80 6.56 6.85 Peak=> r 10 4.14 5.03 5.65 6.45 7.29 7.61 11 3.93 4.78 5.36 6.13 6.92 7.23 12 3.72 4.53 5.08 5.80 6.56 6.85 13 3.52 4.28 4.80 5.48 6.20 6.47 14 3.31 4.02 4.52 5.16 5.83 6.09 15 3.10 3.77 4.23 4.84 5.47 5.71 16 2.90 3.52 3.95 4.51 5.10 5.33 17 2.69 3.27 3.67 4.19 4.74 4.95 18 2.48 3.02 3.39 3.87 4.37 4.57 19 2.27 2.77 3.10 3.55 4.01 4.19 20 2.07 2.51 2.82 3.22 3.64 3.80 21 1.86 2.26 2.54 2.90 3.28 3.42 22 1.65 2.01 2.26 2.58 2.92 3.04 23 1.45 1.76 1.98 2.26 2.55 2.66 24 1.24 1.51 1.69 1.93 2.19 2.28 25 1.03 1.26 1.41 1.61 1.82 1.90 26 0.83 1.01 1.13 1.29 1.46 1.52 27 0.62 0.75 0.85 0.97 1.09 1.14 28 0.41 0.50 0.56 0.64 0.73 0.76 29 0.21 0.25 0.28 0.32 0.36 0.38 30 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development Flow Routed Through Detention Pond Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.38 0.46 0.52 0.59 0.67 0.70 2 0.76 0.93 1.04 1.19 1.34 1.40 3 1.14 1.39 1.56 1.78 2.01 2.10 4 1.52 1.85 2.08 2.37 2.68 2.80 5 1.90 2.31 2.60 2.97 3.35 3.50 6 2.28 2.78 3.12 3.56 4.03 4.20 7 2.66 3.24 3.64 4.15 4.70 4.90 8 3.05 3.70 4.16 4.75 5.37 5.60 9 3.43 4.17 4.68 5.34 6.04 6.30 Peak=> I 10 3.81 4.63 5.20 5.93 6.71 7.00 11 3.62 4.40 4.94 5.64 6.37 6.65 12 3.43 4.17 4.68 5.34 6.04 6.30 13 3.24 3.93 4.42 5.04 5.70 5.95 14 3.05 3.70 4.16 4.75 5.37 5.60 15 2.86 3.47 3.90 4.45 5.03 5.25 16 2.66 3.24 3.64 4.15 4.70 4.90 17 2.47 3.01 3.38 3.86 4.36 4.55 18 2.28 2.78 3.12 3.56 4.03 4.20 19 2.09 2.55 2.86 3.26 3.69 3.85 20 1.90 2.31 2.60 2.97 3.35 3.50 21 1.71 2.08 2.34 2.67 3.02 3.15 22 1.52 1.85 2.08 2.37 2.68 2.80 23 1.33 1.62 1.82 2.08 2.35 2.45 24 1.14 1.39 1.56 1.78 2.01 2.10 25 0.95 1.16 1.30 1.48 1.68 1.75 26 0.76 0.93 1.04 1.19 1.34 1.40 27 0.57 0.69 0.78 0.89 1.01 1.05 28 0.38 0.46 0.52 0.59 0.67 0.70 29 0.19 0.23 0.26 0.30 0.34 0.35 30 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development "Free-Flow" Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.03 0.04 0.04 0.05 0.06 0.06 2 0.07 0.08 0.09 0.10 0.12 0.12 3 0.10 0.12 0.13 0.15 0.17 0.18 4 0.13 0.16 0.18 0.21 0.23 0.24 5 0.16 0.20 0.22 0.26 0.29 0.30 6 0.20 0.24 0.27 0.31 0.35 0.36 7 0.23 0.28 0.31 0.36 0.41 0.42 8 0.26 0.32 0.36 0.41 0.46 0.48 0.30 0.36 0.40 0.46 0.52 0.55 Peak=> ~ 10 Q0.33 0.40 0~45-._·. 0.51' ' 0.58 0.61 0.31 0.38 0.43 0.49 0.55 0.58 12 0.30 0.36 0.40 0.46 0.52 0.55 13 0.28 0.34 0.38 0.44 0.49 0.51 14 0.26 0.32 0.36 0.41 0.46 0.48 15 0.25 0.30 0.34 0.38 0.44 0.45 16 0.23 0.28 0.31 0.36 0.41 0.42 17 0.21 0.26 0.29 0.33 0.38 0.39 18 0.20 0.24 0.27 0.31 0.35 0.36 19 0.18 0.22 0.25 0.28 0.32 0.33 20 0.16 0.20 0.22 0.26 0.29 0.30 21 0.15 0.18 0.20 0.23 0.26 0.27 22 0.13 0.16 0.18 0.21 0.23 0.24 23 0.12 0.14 0.16 0.18 0.20 0.21 24 0.10 0.12 0.13 0.15 0.17 0.18 25 0.08 0.10 0.11 0.13 0.15 0.15 26 0.07 0.08 0.09 0.10 0.12 0.12 27 0.05 0.06 0.07 0.08 0.09 0.09 28 0.03 0.04 0.04 0.05 0.06 0.06 29 0.02 0.02 0.02 0.03 0.03 0.03 30 0.00 0.00 0.00 0.00 0.00 0.00 Total Pre-Development Vs . Total Post-Development (No Detention) Peak Discharge Rates 2-Year Storm Event l 4 .00 +-----+---~'P"o.::----+----+-----+------l u.. 3.50 +----+-----,,_+--~~-t-----t-----+----1 o-:0 -g 3.00 +----+----.,.--+-----1"'oo~---t-----+----I :::J 0 ~ ~ 2 .50 & .. 2.00 +----~----71-o=----l----~----+-----l 0 t. 1.50 +-----:,_-t----:7"""---+----=-+-::::-----+--~.::::---+-------1 .c. bt 0 1.00 +----.,_--::;.,j£'----+-----t-----=-i-=---~~---1 0.50 +-,~,,,C---1-------+----+----+-----'=""'"'k:::-'='"'7---l 0 .00 ~--_ ..... ___ ....,. ___ ...... ___ ....., ___ ....., ____ _ 0 5 10 15 20 25 30 Time (Minutes ) ---Pre -Development Hydrograph ---Tot al Post-Development Hydrograph Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event 6 .00 -----,-------.-----r------.------.----~ 5 .00 ------r------=-----r------r-----;------; 5 10 15 20 25 Time (Minutes ) ---Pre -Devel o pment Hydrograph ---Post-Development Outflow Hyd ro graph Wi t hout Det e ntion 30 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Event 0 ...... :0 'O 5.00 +----+-----..~c--~.,,..---t----+----+-----l :::J 5 Q ~ 4 .00 & ~ 3.00 +----~---+----+---"""""'d:-----t------i ~ G> ~ ~ 2 .00+----,,~+-~.-C--+----==-+-=---+---=~.,.---+------i .~ * l 00 ..__,._~-+-----+-----+---+--=---...::::---+--=""'-:::--~ 0 u.. . 0 .00 .,.... __ ---4i-----+----+----+------4i-------. 0 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph ---Post-Development Outflow Hy drograph With out Detention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 30 7.00----~---~---~---~---~--~ ~ ,, 6.00 +----+---__,,.+=""""'""=:-----+----+----+-----l 8 5 5.00 +----+---1--+----"""'od:----+----+---~ _o G> ~ 4 .00 +----+~--+----+__;:=-....:::--+-----+------l ~ ~ 3.00 +---~"1----:::iJ"'"t"-....::::--+-----f""oi..:::----+-----l s:. A. ~ i 2.00 0 u.. 1.00 +--f-~=--t----+----+----+---="""""......._::f-~..:::----l 0 .00 ...... -----4~---+----+----+------4~---=- o 5 10 15 20 25 Time (Minutes) ---Pre-Development Hy d rog raph ---Post-Developm ent Outflow Hy d rograph Witho ut Detenti o n 30 i 8.00 7.00 ~ .2 ~ 6.00 .g 6 5.00 u 0 4.00 -Cl> Cl> Cl) 3.00 CJ) .... .... G> 0 1CL 2.00 .t: -~ l.00 c 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 50-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 ---Pre-Development Hydrograph ---Post-Development Outflow Hydrograph Without Detention Total Pre-Development Vs . Total Post-Development (No Detention) Peak Discharge Rates 100-Year Storm Event l.00+--F-~;__+-----+-----+-----+--~-.1.:~3',,,,,--~ 0.00 ...-.---+------t----+----+-----+---~ 0 5 10 15 20 25 nme (Minutes) Pre-Development Hydrograph Post-Development Outflow Hydrograph Without Detention 30 Detention Pond De th Vs. Volume 3.00 2.50 i 2.00 G> ~ -~ G> 0 1.50 0.50 0 Elevation Depth Volume (Feet) (Ft3) 293 .59 0.00 0 294.05 0.46 141 294.55 0.96 536 295 .00 1.41 1,216 296 .00 2.41 2,726 296 .68 3 .09 3,753 Detention Pond Depth Vs. Volume 500 1.000 1.500 2 ,000 2,500 3 ,000 3 ,500 4 ,000 Detention Pond Volume (Cubic Feet) Rating Curve For Outlet Control Structure Weir Length(L): 0.25 De th Vs. Volume Elevation Depth Discharge (Feet) Ft3/Sec 293.59 0.00 0.00 294 .05 0 .46 0 .23 294.55 0.96 0.71 295 .00 1.41 1.26 296 .00 2.4 1 2.81 296 .68 3 .09 4 .07 Rating Curve For Outlet Control Structure Depth Vs. 3.50 3.00 2.50 i 2.00 G> u.. -a G> 0 1.50 1.00 0.50 0.00 / / J I Volume ~' / v / / / ~ ~ v (3") 0.00 0 .50 1.00 1.50 2.00 2.50 3.00 3.50 4 .00 4 .50 Discharge (Cubic Feet Per Second) I Storage Indication Curve 4.50 'O 4.00 c 0 ~ 3.50 l. 3.00 1 2.50 u.. 0 :0 2 00 ::;, . ~ Cl> 1.50 O> 0 .&; 1.00 ~ 0 0.50 v 0.00 0.00 Depth (Feet) 0.00 0.46 0.96 1.41 2.41 3.09 / _,, 20.00 Storage Discharge 2s/t 2s/t+O (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0 0.00 0.00 0.00 141 0 .23 4 .72 4.95 536 0.71 17.88 18.59 1,2 16 1.26 40.53 41.79 2,726 2.81 90.86 93 .67 3,753 4.07 125.09 129.17 Storage Indication Curve ~ / v v / / ~ ,/ ~ / V' 40 .00 60 .00 80.00 100.00 120.00 140.00 2s/t+O (Cubic Feet Per Second) Inflow I Outflow Simulation 2-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.59 0.00 1 0.38 0.38 0.34 0.38 0.02 0.08 293.67 0.87 2 0.76 1.14 1.35 1.49 0.07 0.21 293.80 1.36 3 1.14 1.90 2.94 3.25 0.15 0.35 293.94 1.77 4 1.52 2.66 5.09 5.61 0.26 0.49 294.08 2.10 5 1.90 3.43 7.81 8.52 0.36 0.61 294.20 2.34 6 2.28 4.19 11.04 11.99 0.48 0.74 294.33 2.58 7 2.66 4.95 14.76 15.99 0.62 0.88 294.47 2.81 8 3.05 5.71 18.97 20.47 0.75 1.00 294.59 3.00 9 3.43 6.47 23.70 25.44 0.87 1.10 294.69 3.15 10 3.81 7.23 28.94 30.94 1.00 1.21 294.80 3.30 11 3.62 7.42 34.11 36.36 1.13 1.31 294.90 3.44 12 3.43 7.04 38.67 41.15 1.24 1.40 294.99 3.55 13 3.24 6.66 42.61 45.33 1.36 1.49 295.08 3.66 14 3.05 6.28 45.96 48.89 1.47 1.56 295.15 3.75 15 2.86 5.90 48.74 51.86 1.56 1.63 295.22 3.83 16 2.66 5.52 51.01 54.26 1.63 1.68 295.27 3.88 17 2.47 5.14 52.78 56.15 1.68 1.72 295.31 3.93 18 2.28 4.76 54.08 57.54 1.73 1.74 295.33 3.96 19 2.09 4.38 54.95 58.46 1.75 1.76 295.35 3.98 20 1.90 4.00 55.41 58.95 1.77 1.77 295.36 3.99 21 1.71 3.62 55.49 59.03 1.77 1.77 295.36 3.99 22 1.52 3.24 55.20 58.73 1.76 1.77 295.36 3.99 23 1.33 2.86 54.57 58.06 1.74 1.75 295.34 3.97 24 1.14 2.47 53.62 57.05 1.71 1.73 295.32 3.95 25 0.95 2.09 52.37 55.72 1.67 1.71 295.30 3.92 26 0.76 1.71 50.84 54.09 1.62 1.67 295.26 3.88 27 0.57 1.33 49.04 52.17 1.57 1.63 295.22 3.83 28 0.38 0.95 46.99 49.99 1.50 1.59 295.18 3.78 29 0.19 0.57 44.71 47.56 1.43 1.54 295.13 3.72 30 0.00 0.19 42.20 44.90 1.35 1.48 295.07 3.65 Inflow /Outflow Simu lation 2-Year Storm Even t 4.50 4.00 3.50 -"O c 0 ~ 3.00 Cl) ... G> A. l> 2.50 G> "" 0 :0 2.00 :J , 0 , -~ 1.50 , !§ 0 1.00 , , , , , 0.50 0.00 0 ----Pre- Developme nt Hydrograph , , , , , , I , -· 5 .... -. , .... , .... .... .... " .... .... .... .... .... -. .... .... " .... -. -. ----.. ·---.. -. -· -------.. 10 15 20 25 30 Ti me (Minutes ) Post- Developme nt Outflow Hydrograph Without Detention ----Post - Developme nt Outflow With Detention -• -• -• Post - Developme nt 'Free- Flow' Inflow I Outflow Simulation 5-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.59 0.00 1 0.46 0.46 0.42 0.46 0.02 0.09 293.68 0.92 2 0.93 1.39 1.64 1.81 0.09 0.24 293.83 1.45 3 1.39 2.31 3.58 3.95 0.19 0.40 293.99 1.89 4 1.85 3.24 6.22 6.82 0.30 0.54 294.13 2.21 5 2.31 4.17 9.54 10.39 0.42 0.68 294.27 2.48 6 2.78 5.09 13.50 14.64 0.57 0.83 294.42 2.74 7 3.24 6.02 18.06 19.52 0.73 0.98 294.57 2.97 8 3.70 6.94 23.29 25.01 0.86 1.09 294.68 3.14 9 4.17 7.87 29.15 31.16 1.00 1.21 294.80 3.31 10 4.63 8.80 35.62 37.95 1.16 1.34 294.93 3.47 11 4.40 9.03 41.96 44.65 1.34 1.47 295.06 3.64 12 4.17 8.56 47.49 50.53 1.52 1.60 295.19 3.79 13 3.93 8.10 52.26 55.60 1.67 1.70 295.29 3.92 14 3.70 7.64 56.30 59.90 1.80 1.79 295.38 4.01 15 3.47 7.18 59.67 63.48 1.90 1.86 295.45 4.09 16 3.24 6.71 62.40 66.38 1.99 1.92 295.51 4.15 17 3.01 6.25 64.54 68.65 2.06 1.96 295.55 4.20 18 2.78 5.79 66.11 70.32 2.11 1.99 295.58 4.23 19 2.55 5.32 67.15 71.43 2.14 2.01 295.60 4.26 20 2.31 4.86 67.69 72.01 2.16 2.02 295.61 4.27 21 2.08 4.40 67.77 72.09 2.16 2.02 295.61 4.27 22 1.85 3.93 67.40 71.70 2.15 2.02 295.61 4.26 23 1.62 3.47 66.62 70.87 2.12 2.00 295.59 4.24 24 1.39 3.01 65.46 69.63 2.09 1.98 295.57 4.22 25 1.16 2.55 63.93 68.00 2.04 1.95 295.54 4.19 26 0.93 2.08 62.05 66.01 1.98 1.91 295.50 4.15 27 0.69 1.62 59.85 63.67 1.91 1.86 295.45 4.10 28 0.46 1.16 57.35 61.01 1.83 1.81 295.40 4.04 29 0.23 0.69 54.56 58.04 1.74 1.75 295.34 3.97 30 0.00 0.23 51.50 54.79 1.64 1.69 295.28 3.90 Inflow/Outflow Simulation 5-Year Storm Event 6.00 5.00 ' , ~ ' ' -, • 1J 4.00 , ' c: , 0 ~ , ' , ' ... , G> ' A. 3.00 -I , ' ' ~ 0 , ' :0 2.00 , :J 0 ' -, ' ~ 0 , =§ 1.00 , 0 , .. . . . . ................ . .......... . ......... 0.00 -1.00 Time (Minutes) Pre-----Post-Post--...... -Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt 'Free- Hydrograph Hydrograph With Flow' Without Detention Detention Inflow I Outflow Simulation 1 0-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes} (Ft3/Sec} (Ft3/Sec} (Feet} (FVSec} 0 0.00 0.00 0.00 0.00 0.00 0.00 293.59 0.00 1 0.52 0.52 0.47 0.52 0.02 0.10 293.69 0.96 2 1.04 1.56 1.84 2.03 0.10 0.25 293.84 1.51 3 1.56 2.60 4.02 4.44 0.21 0.43 294.02 1.96 4 2.08 3.64 7.00 7.65 0.33 0.58 294.17 2.28 5 2.60 4.68 10.74 11.67 0.47 0.73 294.32 2.56 6 3.12 5.72 15.19 16.46 0.63 0.89 294.48 2.83 7 3.64 6.75 20.38 21.95 0.79 1.03 294.62 3.05 8 4.16 7.79 26.31 28.17 0.93 1.16 294.75 3.23 9 4.68 8.83 32.94 35.14 1.10 1.29 294.88 3.41 10 5.20 9.87 40.24 42.82 1.29 1.43 295.02 3.59 11 4.94 10.13 47.35 50.38 1.51 1.60 295.19 3.79 12 4.68 9.61 53.55 56.96 1.71 1.73 295.32 3.95 13 4.42 9.09 58.88 62.64 1.88 1.84 295.43 4.07 14 4.16 8.57 63.41 67.45 2.02 1.94 295.53 4.18 15 3.90 8.05 67.18 71.46 2.14 2.01 295.60 4.26 16 3.64 7.53 70.23 74.71 2.24 2.07 295.66 4.32 17 3.38 7.01 72.62 77.25 2.32 2.12 295.71 4.37 18 3.12 6.50 74.37 79.11 2.37 2.15 295.74 4.40 19 2.86 5.98 75.53 80.35 2.41 2.18 295.77 4.43 20 2.60 5.46 76.13 80.99 2.43 2.19 295.78 4.44 21 2.34 4.94 76.21 81.07 2.43 2.19 295.78 4.44 22 2.08 4.42 75.79 80.63 2.42 2.18 295.77 4.43 23 1.82 3.90 74.91 79.69 2.39 2.16 295.75 4.41 24 1.56 3.38 73.60 78.29 2.35 2.14 295.73 4.39 25 1.30 2.86 71.87 76.46 2.29 2.11 295.70 4.35 26 1.04 2.34 69.76 74.21 2.22 2.06 295.65 4.31 27 0.78 1.82 67.29 71.58 2.15 2.02 295.61 4.26 28 0.52 1.30 64.47 68.59 2.06 1.96 295.55 4.20 29 0.26 0.78 61.34 65.25 1.96 1.90 295.49 4.13 30 0.00 0.26 57.90 61.60 1.85 1.82 295.41 4.05 Inflow /Outflow Simulation 10 -Year Storm Even t 6.00 I ' I I ' "' 5.00 I ' I ' I ' I ' I -' 'O 4.00 I c: • 0 ' ~ I ' I ' ... ' G> I Q.. I ' l I ' 3.00 ' u.. 0 ' :0 I :J ' 0 I -. -~ I 0 I !§ I ' 2.00 0 I I ' I ' I I ' • ' 1.00 ' ' I ' ' . . . ....... .. ..... . . . . . . .. ..... . .......... .. ...... .. .. .. .. .. ...... 0.00 0 5 10 15 20 25 30 Ti me (Min utes ) Pre-. . . . Post-Post -. ........ Post- Developme Developme Developme De velo pme nt nt Outflow nt Outflow nt 'Free- Hydrograph Hydr ograph With Flow' Without Detention Detenti on Inflow I Outflow Simulation 25-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.59 0.00 1 0.59 0.59 0.54 0.59 0.03 0.11 293.70 1.00 2 1.19 1.78 2.10 2.32 0.11 0.28 293.87 1.58 3 1.78 2.97 4.59 5.07 0.24 0.47 294.06 2.05 4 2.37 4.15 8.01 8.74 0.37 0.62 294.21 2.36 5 2.97 5.34 12.31 13.35 0.52 0.79 294.38 2.66 6 3.56 6.53 17.41 18.83 0.71 0.97 294.56 2.95 7 4.15 7.71 23.40 25.13 0.86 1.10 294.69 3.14 8 4.75 8.90 30.24 32.31 1.03 1.24 294.83 3.34 9 5.34 10.09 37.89 40.33 1.22 1.38 294.97 3.53 10 5.93 11.28 46.21 49.17 1.48 1.57 295.16 3.76 11 5.64 11.57 54.32 57.79 1.73 1.75 295.34 3.97 12 5.34 10.98 61.38 65.30 1.96 1.90 295.49 4.13 13 5.04 10.39 67.46 71.77 2.15 2.02 295.61 4.26 14 4.75 9.79 72.62 77.25 2.32 2.12 295.71 4.37 15 4.45 9.20 76.92 81.82 2.45 2.20 295.79 4.45 16 4.15 8.60 80.40 85.52 2.56 2.27 295.86 4.52 17 3.86 8.01 83.11 88.41 2.65 2.32 295.91 4.57 18 3.56 7.42 85.10 90.53 2.71 2.36 295.95 4.60 19 3.26 6.82 86.42 91.93 2.75 2.38 295.97 4.63 20 2.97 6.23 87.10 92.65 2.78 2.39 295.98 4.64 21 2.67 5.64 87.18 92.74 2.78 2.39 295.98 4.64 22 2.37 5.04 86.70 92.23 2.76 2.39 295.98 4.63 23 2.08 4.45 85.69 91.15 2.73 2.37 295.96 4.62 24 1.78 3.86 84.18 89.55 2.68 2.34 295.93 4.59 25 1.48 3.26 82.21 87.45 2.62 2.30 295.89 4.55 26 1.19 2.67 79.79 84.88 2.54 2.26 295.85 4.51 27 0.89 2.08 76.96 81.87 2.45 2.20 295.79 4.45 28 0.59 1.48 73.74 78.44 2.35 2.14 295.73 4.39 29 0.30 0.89 70.16 74.63 2.24 2.07 295.66 4.32 30 0.00 0.30 66.23 70.45 2.11 1.99 295.58 4.24 Inflow/Outflow Simulation 25-Year Storm Event 7.00 Inflow I Outflow Simulation 50-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0 .00 0 .00 293.59 0.00 1 0.67 0 .67 0.61 0.67 0.03 0.12 293 .71 1.05 2 1 .34 2 .01 2 .37 2.62 0.12 0.30 293.89 1.65 3 2 .01 3.35 5.20 5.73 0.26 0.49 294.08 2.11 4 2.68 4.70 9 .09 9 .90 0.41 0 .66 294.25 2.44 5 3.35 6 .04 13 .96 15.13 0 .59 0 .85 294.44 2.76 6 4 .03 7.38 19.79 21.34 0.77 1.02 294.61 3 .03 7 4.70 8 .72 26 .63 28 .51 0 .94 1.16 294 .75 3.24 8 5 .37 10.06 34.43 36.70 1 .13 1.32 294 .91 3.44 9 6 .04 11.40 43.08 45 .83 1 .38 1 .50 295.09 3.67 10 6 .7 1 12 .75 52.47 55 .82 1.68 1 .71 295.30 3.92 11 6.37 13.08 61.62 65 .55 1 .97 1 .90 295.49 4.14 12 6 .04 12.41 69 .59 74.03 2 .22 2.06 295 .65 4.31 13 5 .70 11.74 76.46 81.33 2.44 2 .19 295.78 4.44 14 5 .37 11 .07 82 .28 87.53 2 .62 2 .30 295.89 4 .55 15 5.03 10.40 87 .13 92.68 2.78 2 .39 295.98 4.64 16 4 .70 9.73 91.02 96.86 2 .92 2.47 296.06 4 .72 17 4 .36 9.06 94.00 100.07 3.03 2.54 296.13 4.78 18 4 .03 8 .39 96 .15 102 .39 3.12 2.59 296 .18 4 .82 19 3 .69 7 .71 97 .53 103.87 3 .17 2 .61 296 .20 4.85 20 3 .35 7 .04 98 .18 104.57 3 .20 2.63 296 .22 4 .86 21 3.02 6.37 98 .16 104.55 3 .19 2 .63 296.22 4 .86 22 2.68 5 .70 97 .53 103 .87 3 .17 2.61 296 .20 4 .85 23 2 .35 5 .03 96 .31 102 .56 3 .12 2 .59 296.18 4 .83 24 2 .01 4 .36 94 .56 100.67 3 .06 2 .55 296.14 4.79 25 1.68 3 .69 92.31 98 .25 2 .97 2 .50 296 .09 4 .75 26 1 .34 3 .02 89.60 95 .33 2 .87 2.44 296 .03 4 .69 27 1.01 2 .35 86.44 91.95 2 .75 2 .38 295 .97 4 .63 28 0.67 1 .68 82 .83 88.11 2 .64 2.31 295 .90 4 .56 29 0 .34 1 .01 78 .82 83.84 2 .51 2 .24 295 .83 4.49 30 0 .00 0.34 74.4 1 79.15 2 .37 2 .15 295.74 4.40 -"O c 0 8 .00 7.00 6.00 £ 5.00 t. l ~ 4 .00 0 :a :J ~ ~ 3.00 =§ 0 2.00 1.00 0.00 0 Inflow/Outflow Simulation 50-Year Storm Event I • I Pre - I I I I • I I I I Developme nt Hydrograph I 5 . I ' I I • I I I I I I I . . . ... . . . 10 " ... " ' " ' .. ..... .. .... .. ' " ' ' .. ....... 15 ' " ' " " .. ........ .. ..... 20 Time (Minutes) . . . Post -Post- Developme Developme nt Outflow nt Outflow Hydrograph With Withou t Detention Detention .. .. .. .. .. .. 25 -------- " .. " 30 Post - Developme nt 'Free- Flow ' Inflow I Outflow Simulation 100-Y ear Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.59 0.00 1 0.70 0.70 0.63 0.70 0.03 0.12 293.71 1.06 2 1.40 2.10 2.48 2.74 0.13 0.31 293.90 1.67 3 2.10 3.50 5.44 5.98 0.27 0.51 294.10 2.13 4 2.80 4.90 9.50 10.34 0.42 0.68 294.27 2.47 5 3.50 6.30 14.59 15.81 0.61 0.87 294.46 2.80 6 4.20 7.70 20.70 22.29 0.79 1.04 294.63 3.06 7 4.90 9.11 27.87 29.81 0.97 1.19 294.78 3.27 8 5.60 10.51 36.02 38.37 1.17 1.35 294.94 3.48 9 6.30 11.91 45.05 47.93 1.44 1.54 295.13 3.73 10 7.00 13.31 54.86 58.36 1.75 1.76 295.35 3.98 11 6.65 13.66 64.41 68.52 2.05 1.96 295.55 4.20 12 6.30 12.96 72.73 77.37 2.32 2.12 295.71 4.37 13 5.95 12.26 79.89 84.98 2.55 2.26 295.85 4.51 14 5.60 11.56 85.97 91.45 2.74 2.37 295.96 4.62 15 5.25 10.86 90.99 96.83 2.92 2.47 296.06 4.72 16 4.90 10.16 95.00 101.14 3.07 2.56 296.15 4.80 17 4.55 9.46 98.07 104.45 3.19 2.63 296.22 4.86 18 4.20 8.76 100.28 106.83 3.28 2.67 296.26 4.90 19 3.85 8.05 101.67 108.33 3.33 2.70 296.29 4.93 20 3.50 7.35 102.32 109.03 3.35 2.71 296.30 4.94 21 3.15 6.65 102.27 108.97 3.35 2.71 296.30 4.94 22 2.80 5.95 101.57 108.22 3.33 2.70 296.29 4.93 23 2.45 5.25 100.27 106.82 3.28 2.67 296.26 4.90 24 2.10 4.55 98.41 104.82 3.20 2.63 296.22 4.87 25 1.75 3.85 96.04 102.27 3.11 2.58 296.17 4.82 26 1.40 3.15 93.19 99.19 3.00 2.52 296.11 4.76 27 1.05 2.45 89.88 95.64 2.88 2.45 296.04 4.70 28 0.70 1.75 86.15 91.64 2.75 2.38 295.97 4.62 29 0.35 1.05 81.97 87.20 2.61 2.30 295.89 4.55 30 0.00 0.35 77.39 82.32 2.47 2.21 295.80 4.46 -"O c 0 8.00 7.00 6.00 ~ 5.00 ~ n. l u. 4 .00 0 :0 :J ~ ~ 3 .00 =§ 0 2.00 1.00 0.00 0 Inflow/Outflow Sim ul ation 100 -Year Storm Ev e nt ' • ' • ' • I ' ' • ' • ' • ' I ' • • ' • • ' • ' • ' • ' • ' ' ' • ' • I ' • • I .. • ' I • ' • ... • ' ' . . . ...... . ... . . . . . . .. ...... .. ....... .. ..... . .. . .. . ..... 5 10 15 20 25 30 Ti me (Min ute s) Pre-----Post-Post-........ Post - Developme Developme Developme Developme nt nt Outflow nt Outflow nt 'Free- Hydrograph Hydrograph With Flow' Without Detention Detention Inflow/Outflow Simulation 2-Year Storm Event 2.00 1.80 1.60 1.40 -'O c 0 0 G> 1.20 Cl) .. G> A. l 1.00 "" 0 :0 :J 0 -~ 0.80 0 =§ 0 0.60 0.40 0.20 0.00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---Total Post-Development Hydrograph -,, c 0 2.50 2 .00 ~ 1.50 ... G> 0.. l u.. 0 :0 ::;, ~ ~ 1.00 0 =§ 0 0 .50 0 .00 0 Inflow/Outflow Simulation 5-Year Storm Event 5 10 15 20 25 30 Time (Minutes ) ----Pre -Development Hydrograph ---•To tal Post -Developm ent Hydrograph Inflow/Outflow Simulation 10-Year Storm Event 3 .00 2.50 13' 2.00 c 0 ~ Cl) .. G> Q.. -; G> l.50 u.. 0 :D :J ~ ~ 0 =§ 0 l.00 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre -Development Hydrograph ----Total Post -Development Hydrograph Inflow/Outflow Simulation 25-Year Storm Event 3.50 3.00 2.50 ....... ,, c 0 ~ Cl) .. 2.00 G> a.. l ..... 0 :0 :J 0 1.50 ....... ~ 0 =§ 0 l.00 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---Total Post-Development Hydrograph Inflow/Outflow Simulation 50 -Year Storm Event 4.00 3.50 3.00 -"O c 0 2 .50 ~ Cl) -Cl> A. -I 2.00 ~ 0 :0 :::> 0 -,.. 0 l.50 !§ 0 l.00 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ----Tota l Post-Devel o pment Hyd rograph Inflow /Outflow Simulation 100-Year Storm Event 4.00 3.50 3.00 ....... ,, c 0 2.50 0 3: .. G> ~ l 2 .00 "'" 0 :0 :J 0 -~ 0 l.50 !§ 0 l.00 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---Total Post-Development Hydrograph 100% 90% 80% 70% :;::- I 60% I.I. 0 :0 :::J 50% 0 -~ :::J 40% 0 > 300k 20% 10% 0% Detention Pond Storage V olumes as Percent of Maximum V olum e 2-year 5-year 10-year 25-year SO-year 100-year Design Storm Design Maximu m Percentage Storm Depth Volume Volume of Maximum 2-year 1.77 1764 3 ,753 47% 5-year 2.02 2144 3,753 57% 10-year 2 .19 2393 3,753 64% 25-year 2.39 2702 3 ,753 72% 50-year 2.63 3055 3 ,753 81% 100-year 2 .7 1 3186 3 ,753 85% {Jv DRAINAGE COMPUTATIONS ~f For Lot 5, Block 1 K.F.O. Addition College Station, Brazos County, Texas Prepared By: Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409} 846-2688 •, DRAINAGE COMPUTATIONS For Lot 5, Block 1, K.F.O. Addition College Station, Brazos County, Texas *November, 1994 * SUMMARY The project is situated adjacent to Manuel Drive and Cornell Street in College Station, Brazos County, Texas. The Lot 5, Block 1 K.F.O. addition consists of 1 lot which is to have a mini-storage complex placed on it The total drainage area tributary to the project is 0.78 acres. The pre-development run-off coefficient was estimated to be 0.40, while taking into account the proposed site improvements would result in a post- development run-off coefficient of 0.83. A detention facility will be constructed along Cornell street and Manuel Drive as designated on the Site & Grading plan .. The detention pond is designed to facilitate up to and including the 100-year storm event, and discharge at a rate less than the current pre-development peak discharge rate. The detention pond will intercept, store and meter run-off from 0.68 acres of the project. The run-off generated on the remaining 0.10 acres will "free-flow" across the project site unmetered off the property. From the computations on page 1, based on the total tributary drainage area of the project being estimated at 0.78 acres, the pre-development run-off coefficient being assumed at 0.40, and a minimum time of concentration of 10 minutes, the relative pre-development peak discharge rate ("Q") was determined. The Rational Method was utilized to compute the estimated peak pre-development discharge rates. The equation that represents the Rational Method is as follows: Q = CIA. "Q" is the peak discharge rate in cubic feet per second, "C" is the run-off coefficient, assumed to be 0.40 in the pre-development condition, "I" is the storm intensity in inches per hour, and" A" is the area of the drainage basin in acres. From the computations on page 2, based on the tributary area of 0.78 acres, the post-development run-off coefficient being assumed at 0.83, and a minimum time of concentration of 10 minutes, the relative pre- development peak discharge rate ("Q") was determined assuming the same minimum time of concentration of 10 minutes. The Rational Method was again utilized to compute the estimated peak post-development discharge rates. The equation that represents the Rational Method is as follows: Q = CIA, where; "Q" is the peak discharge rate in cubic feet per second. "C" is the run-off coefficient, in the post-development condition "C" is assumed to be 0.83, "I" is the stonn intensity in inches per hour and "A" is the area of the drainage basin in acres. The comparison between the peak pre-development discharge rate and post-development discharge rate is included as an aid to the designer to establish a preliminary "target" for the necessary volllllle in the proposed detention facility. This preliminary estimate is found by simply determining the volllllle generated from the difference between the pre-development and post-development hydrographs (see pages 9-11 for pre- development and post-development hydrographs). Please note that the post-development hydrograph shown on these same graphs assumes no detention. Page 3 and page 4 provide computations that determine the post-development run-off that is not routed through the detention facility ("free-flow") and post-development run-off that is routed through the detention facility. Page 5 and page 6 are tabulations of the pre-development hydrograph and the post-development hydrograph based on the computations performed on page l and page 2. The post-development hydrograph assumes no detention to facilitate direct comparison in the pre-and post-development conditions. Page 7 and page 8 are tabulations of the post-development hydrograph for run-off directed through the detention facility and the post-development hydrograph for "free-flow" from the project site. Computations on page 4 determine the actual peak post-development "inflow" rate supplied to the proposed detention facility . From this "inflow" rate and the time of concentration (10 minutes minimum), a hydrograph as tabulated on page 8 can be derived. The hydrograph is triangular in shape and is based on the standard SCS unit hydrograph with time to peak set equal to the time of concentration and the total time base set at 3 .00 times the time of concentration . Please note that a 30 minute total storm event duration was utilized exclusively throughout this report due totally to the small physical size of the project Having derived the preliminary volume requirements and "allowable peak" discharge rate, it is now p0ssible to design the final detention facility and outlet control structure. Page 12 presents a tabulation and a depth versus volwne graph of the detention facility. The maximum depth of the pond was set at 3 .09' (top retaining wall less flow line "out" of outlet control structure: 296.68' -293 .59' = 3 .09'). Page 13 supplies a tabulation and a rating curve for the proposed outlet control structure .. A rectangular weir was decided upon due to depth verses discharge ratio characteristics associated with the anticipated shallow headwater depth (maximum of 3 .09') and the fixed weir width of 0.25' (3"). The equation used to determine discharge was Q = CLH3/2 where "Q " is the discharge rate in cubic feet per second. "C" is the coefficient of discharge, in this case assumed to be set at 3.000. "L" is the width of the weir in feet, in this case assumed to be set at 0 .25'. "H" is the headwater depth in feet (ranges from O' to a maximum of 3 .09'). Page 14 presents a tabulation of the relationship between discharge from the detention facility and the dimensionless quantity 2S/t-O. Also presented is a Storage Indication Curve for the detention facility based on the aforementioned physical characteristics of the detention pond, storage volume, inflow hydrograph, and rating curve for the outlet structure. The storage indication curve as shown on page 12 is a graphical solution to the equation presented in the "Draina2e Policy And Desi2n Stand.ards" as follows: 2s 1 (I 1 + 12) + (----------------01) dt 2s2 = (-----------------+ 02) dt Page 15 through page 26 present simulations of the 2, 5 , 10, 25 , 50, and 100 year storm events. The first page of each storm simulation represents the tabulated data for the storm event. The maximum depth achieved in the detention pond during each simulation is shown below as is the time period during which this maximum depth occurs after the beginning of the storm event. The calculated peak discharge rate corresponding to this depth over same period is also shown below . Additionally, the maximum water surface elevation achieved during each event and the maximum peak discharge during each event are listed below. The second page of each storm simulation represents the pre-development hydrograph, the post-development hydrograph (with no detention), the post-development hydrograph as routed through the detention pond , and post-development "free-flow" hydrograph for each storm event Storm Max Depth (Year) (Ft) 2-year 1.77 5-year 2 .02 IO-year 2 .19 25-year 2.39 50-year 2.63 100-year2.71 Time Period (Min) 20 -22 20-22 20-21 20-22 20-21 20-21 Max Discharge Max Elev (CFS) (Ft MSL) 1.77 295 .36 2.16 295 .61 2.43 295.78 2.78 295 .98 3.20 296.22 3.35 296 .30 Max Velocity (Ft/Sec) 3.99 4 .27 4 .44 4.64 4 .86 4 .94 Page 27 through page 32 provide total inflow/outflow hydrographs for the 2, 5, 10, 25, 50 and 100-year pre- development and post-development storm events . It can be determined from these same hydrographs that the post-development peak discharge rates have been minutely decreased from those peak pre-development discharge rates due to the incorporation of the detention facility in the post-development condition. Total post-development peak discharge rates from the detention pond outlet control structure and project site are kept less than the pre-development peak discharge rates due to the incorporation of the proposed detention facilities. Subsequent peak post-development discharge velocities projected to be within manageable limits . Tributary Area ("A"): 0 .78 Acres Pervious Area : 0.78 Acres C= 0.40 Impervious Area : 0.00 Acres C= 0.98 Run-Off Coefficient ("Cwt"): 0.40 Time Of Concentration ("T/c"): Woodlands: Low Elevation: 0.00 High Elevation: 0 .00 Distance (Feet): 0.00 Slope (% Grade): 0 .00 Velocity ("Vw"): 0 .00 Feet I Second Time : 0.00 Minutes Pastures: Low Elevation: 0 .00 High Elevation: 0 .00 Distance (Feet): 0 .00 Slope (% Grade): 0.00 Velocity ("Vp"): 0 .00 Feet I Second Time: 0 .00 Minutes Pavements: Low Elevation : 0 .00 High Elevation : 0 .00 Distance (Feet): 0 .00 Slope (% Grade): 0 .00 Velocity ("Vpave"): 0 .00 Feet I Second Time : 0 .00 Minutes Total Travel Time: 10.00 Minutes Hourly Intensity Rates ("I "): 2-Year: 6.33 Inches I Hour 5-Year: 7 .69 Inches I Hour 10-Year: 8.63 Inches I Hour 25-Year: 9 .86 Inches I Hour 50-Year: 11.15 Inches I Hour 100-Year: 11.64 Inches I Hour Peak Discharge Rate ("Q "): 2-Year: 1.99 Cubic Feet I Second 5-Year: 2.42 Cubic Feet I Second 10-Year: 2 .72 Cubic Feet I Second 25-Year: 3 .10 Cubic Feet I Second 50-Year: 3.51 Cubic Feet I Second 100-Year: 3 .66 Cubic Feet I Second Tributary Area ("A"): 0.78 Acres Perv ious Area : 0.20 Acres C= 0.40 Impervious Area : 0.58 Acres C= 0.98 Run-Off Coefficient ("Cwt "): 0.83 Time Of Concentration ("T/c "): 1 O Minutes (M in) Hourly Intensity Rates ("I "): 2-Year: 6.33 Inches I Hour 5-Year: 7.69 Inches I Hour 10-Year: 8.63 Inches I Hour 25-Year: 9.86 Inches I Hour 50-Year: 11.15 Inches I Hour 100-Year: 11 .64 Inches I Hour Peak Discharge Rate ("Q "): 2-Year: 4 .14 Cubic Feet I Second 5-Year: 5.03 Cubic Feet I Second 10-Year: 5.65 Cubic Feet I Second 25-Year: 6.45 Cubic Feet I Second 50-Year: 7.29 Cubic Feet I Second 100-Year: 7.61 Cubic Feet I Second Predevelopment Post-Development Increase 2-Year: 1.99 Ft3/sec 4.14 Ft3/sec 2 .15 Ft3/sec 5-Year: 2.42 Ft3/sec 5.03 Ft3/sec 2 .61 Ft3/sec 10-Year: 2 .72 Ft3/sec 5.65 Ft3/sec 2 .93 Ft3/sec 25-Year: 3 .1 O Ft3/sec 6.45 Ft3/sec 3 .35 Ft3 /sec 50-Year: 3 .51 Ft3/sec 7.29 Ft3/sec 3.78 Ft3/sec 100-Year: 3.66 Ft3/sec 7 .61 Ft3/sec 3 .95 Ft3/sec 2-Year: 2 .15 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 1,931 Cubic Feet 5-Year: 2.61 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 2 ,348 Cubic Feet 10-Year: 2.93 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 2 ,636 Cubic Feet 25-Year: 3 .35 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 3,011 Cubic Feet 50-Year: 3. 78 Ft3/sec x (30 Min. x 60 Sec. I 2 ) = 3 ,403 Cubic Feet 100-Year: 3.95 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 3,553 Cubic Feet Tributary Area ("A "): 0.10 Acres Pervious Area : 0.08 Acres C: 0.40 Impervious Area : 0.02 Acres C= 0.98 Run-Off Coefficient ("Cwt"): 0.52 Time Of Concentration ("T/c"): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 Inches I Hour 5-Year: 7.69 Inches I Hour 10-Year: 8.63 Inches I Hour 25-Year: 9.86 Inches I Hour 50-Year: 11 .15 Inches I Hour 100-Year: 11.64 Inches I Hour Peak Discharge Rate ("Q"): 2-Year: 0 .33 Cubic Feet I Second 5-Year: 0.40 Cubic Feet I Second 10-Year: 0.45 Cubic Feet I Second 25-Year: 0.51 Cubic Feet I Second 50-Year: 0.58 Cubic Feet I Second 100-Year: 0.61 Cubic Feet I Second Tributary Area ("A"): 0 .68 Acres Pervious Area: 0 .12 Acres c = 0.40 Impervious Area: 0 .56 Acres C= 0.98 Run-Off Coefficient ("Cwt"): 0.88 Time Of Concentration ("Tic "): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 Inches I Hour 5-Year: 7.69 Inches I Hour 10-Year: 8.63 Inches I Hour 25-Year: 9.86 Inches I Hour 50-Year: 11 .15 Inches I Hour 100-Year: 11 .64 Inches I Hour Peak Discharge Rate ("Q "): 2-Year: 3.81 Cubic Feet I Second 5-Year: 4.63 Cubic Feet I Second 10-Year: 5 .20 Cubic Feet I Second 25-Year: 5 .93 Cubic Feet I Second SO -Year: 6.71 Cubic Feet I Second 100-Year: 7 .00 Cubic Feet I Second Pre-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) nme 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.20 0.24 0.27 0.31 0.35 0.37 2 0.40 0.48 0.54 0.62 0.70 0.73 3. 0.60 0.73 0.81 0.93 1.05 1.10 4 0.80 0.97 1.09 1.24 1.40 1.46 5 1.00 1.21 1.36 1.55 1.75 1.83 6 1.19 1.45 1.63 1.86 2.10 2.20 7 1.39 1.69 1.90 2.17 2.45 2.56 8 1.59 1.94 2.17 2.48 2.81 2.93 9 1.79 2.18 2.44 2.79 3.16 3.30 Peak=> &l~~2;j~2:12&~sJ:0;~~[§~:a-a 1.89 2.30 2.58 2.95 3.33 3.48 12 1.79 2.18 2.44 2.79 3.16 3.30 13 1.69 2.06 2.31 2.64 2.98 3.11 14 1.59 1.94 2.17 2.48 2.81 2.93 15 1.49 1.82 2.04 2.33 2.63 2.75 16 1.39 1.69 1.90 2.17 2.45 2.56 17 1.29 1.57 1.77 2.02 2.28 2.38 18 1.19 1.45 1.63 1.86 2.10 2.20 19 1.09 1.33 1.49 1.71 1.93 2.01 20 1.00 1.21 1.36 1.55 1.75 1.83 21 0.90 1.09 1.22 1.40 1.58 1.65 22 0.80 0.97 1.09 1.24 1.40 1.46 23 0.70 0.85 0.95 1.09 1.23 1.28 24 0.60 0.73 0.81 0.93 1.05 1.10 25 0.50 0.61 0.68 0.78 0.88 0.92 26 0.40 0.48 0.54 0.62 0.70 0.73 27 0.30 0.36 0.41 0.47 0.53 0.55 28 0.20 0.24 0.27 0.31 0.35 0.37 29 0.10 0.12 0.14 0.16 0.18 0.18 30 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) TI me 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.41 0.50 0.56 0.64 0.73 0.76 2 0.83 1.01 1.13 1.29 1.46 1.52 3 1.24 1.51 1.69 1.93 2.19 2.28 4 1.65 2.01 2.26 2.58 2.92 3.04 5 2.07 2.51 2.82 3.22 3.64 3.80 6 2.48 3.02 3.39 3.87 4.37 4.57 7 2.90 3.52 3.95 4.51 5.10 5.33 8 3.31 4.02 4.52 5.16 5.83 6.09 9 3.72 4.53 5.08 5.80 6.56 6.85 Peak=> IED~~3:4-:illii~431t~ii~~~ 11 3.93 4.78 5.36 6.13 6.92 7.23 12 3.72 4.53 5.08 5.80 6.56 6.85 13 3.52 4.28 4.80 5.48 6.20 6.47 14 3.31 4.02 4.52 5.16 5.83 6.09 15 3.10 3.77 4.23 4.84 5.47 5.71 16 2.90 3.52 3.95 4.51 5.10 5.33 17 2.69 3.27 3.67 4.19 4.74 4.95 18 2.48 3.02 3.39 3.87 4.37 4.57 19 2.27 2.77 3.10 3.55 4.01 4.19 20 2.07 2.51 2.82 3.22 3.64 3.80 21 1.86 2.26 2.54 2.90 3.28 3.42 22 1.65 2.01 2.26 2.58 2.92 3.04 23 1.45 1.76 1.98 2.26 2.55 2.66 24 1.24 1.51 1.69 1.93 2.19 2.28 25 1.03 1.26 1.41 1.61 1.82 1.90 26 0.83 1.01 1.13 1.29 1.46 1.52 27 0.62 0.75 0.85 0.97 1.09 1.14 28 0.41 0.50 0.56 0.64 0.73 0.76 29 0.21 0.25 0.28 0.32 0.36 0.38 30 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development Flow Routed Through Detention Pond Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.38 0.46 0.52 0.59 0.67 0.70 2 0.76 0.93 1.04 1.19 1.34 1.40 3 1.14 1.39 1.56 1.78 2.01 2.10 4 1.52 1.85 2.08 2.37 2.68 2.80 5 1.90 2.31 2.60 2.97 3.35 3.50 6 2.28 2.78 3.12 3.56 4.03 4.20 7 2.66 3.24 3.64 4.15 4.70 4.90 8 3.05 3.70 4.16 4.75 5.37 5.60 9 3.43 4.17 4.68 5.34 6.04 6.30 Peak=> Mio;;M~Jl~dili4:6.3™5:2'.oiasMMK"§:tt !Mllii® 11 3.62 4.40 4.94 5.64 6.37 6.65 12 3.43 4.17 4.68 5.34 6.04 6.30 13 3.24 3.93 4.42 5.04 5.70 5.95 14 3.05 3.70 4.16 4.75 5.37 5.60 15 2.86 3.47 3.90 4.45 5.03 5.25 16 2.66 3.24 3.64 4.15 4.70 4.90 17 2.47 3.01 3.38 3.86 4.36 4.55 18 2.28 2.78 3.12 3.56 4.03 4.20 19 2.09 2.55 2.86 3.26 3.69 3.85 20 1.90 2.31 2.60 2.97 3.35 3.50 21 1.71 2.08 2.34 2.67 3.02 3.15 22 1.52 1.85 2.08 2.37 2.68 2.80 23 1.33 1.62 1.82 2.08 2.35 2.45 24 1.14 1.39 1.56 1.78 2.01 2.10 25 0.95 1.16 1.30 1.48 1.68 1.75 26 0.76 0.93 1.04 1.19 1.34 1.40 27 0.57 0.69 0.78 0.89 1.01 1.05 28 0.38 0.46 0.52 0.59 0.67 0.70 29 0.19 0.23 0.26 0.30 0.34 0.35 30 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development "Free-Flow" Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.03 0.04 0.04 0.05 0.06 0.06 2 0.07 0.08 0.09 0.10 0.12 0.12 3 0.10 0.12 0.13 0.15 0.17 0.18 4 0.13 0.16 0.18 0.21 0.23 0.24 5 0.16 0.20 0.22 0.26 0.29 0.30 6 0.20 0.24 0.27 0.31 0.35 0.36 7 0.23 0.28 0.31 0.36 0.41 0.42 8 0.26 0.32 0.36 0.41 0.46 0.48 9 0.30 0.36 0.40 0.46 0.52 0.55 Peak=> Wm• Mo:33@Mib·)'QiM015i!iM.bt5tiMM0$4* tu:St 11 0.31 0.38 0.43 0.49 0.55 0.58 12 0.30 0.36 0.40 0.46 0.52 0.55 13 0.28 0.34 0.38 0.44 0.49 0.51 14 0.26 0.32 0.36 0.41 0.46 0.48 15 0.25 0.30 0.34 0.38 0.44 0.45 16 0.23 0.28 0.31 0.36 0.41 0.42 17 0.21 0.26 0.29 0.33 0.38 0.39 18 0.20 0.24 0.27 0.31 0.35 0.36 19 0.18 0.22 0.25 0.28 0.32 0.33 20 0.16 0.20 0.22 0.26 0.29 0.30 21 0.15 0.18 0.20 0.23 0.26 0.27 22 0.13 0.16 0.18 0.21 0.23 0.24 23 0.12 0.14 0.16 0.18 0.20 0.21 24 0.10 0.12 0.13 0.15 0.17 0.18 25 0.08 0.10 0.11 0.13 0.15 0.15 26 0.07 0.08 0.09 0.10 0.12 0.12 27 0.05 0.06 0.07 0.08 -0.09 0.09 28 0.03 0.04 0.04 0.05 0.06 0.06 29 0.02 0.02 0.02 0.03 0.03 0.03 30 0.00 0.00 0.00 0.00 0.00 0.00 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rotes 2-Yeor Storm Event 4 .50-----.,..-----......-----..-----~---~--~ i ~:~ +-----+---#--+--~::--t------+----+-------i o-~ ~ 3 .00+----+-~~-+-----'"""-::----t----t-------l §, ~ 2.50 & ~ 2.00 ...._--~--_.,.,..c:::----+----~:------+--~ ~ t. 1.50 ~ 1.00 +-~~--"7i'~---+----t---___;::"""'+-o=---__::~------i 0 0.50 .........,,._,,,,£---l-----+----+----t----'=--+.c::--.::::11~----i 0.00 ...-------41-----+---+----..... ---+--..;;;; .. 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---Total Post-Development Hydrograph Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rotes 5-Yeor Storm Event 6.00 -----.....-----.....-----.,..-----.,..-----,.--------. i 5.00 +-----+----_.,,.1111:;::-----+----+-----+-------! .!:! tt; 4 00 ~ c . +-----+---1--+-----''""""'=+----+----+-----I ~ 0 ~ j 3.00 +----~;__--+-----t---.::.OllE:'.-+----+------l t ~ 2.00 +--~L-t---7"'""--1--......::::3--;::±-----t---"'-.....:---t-------i ~ Q. .~ 0 1.00 +-~~~::+----+----+----+=--=:--t3'i1111:;::----I 0.00 _____ ,._ ___ ,._ ___ ,._ ___ ,._ ___ .... ___ ~ 0 5 10 15 20 25 Time (Minutes) ---Pre -Development Hydrograph ---Post-Deve lopment Outfl ow Hydrograph Without Detention 30 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Event () -00 ~ ~ 5. +----+---~+--31._,__-+-----+-----+----~ § j 4.00 & .. 3.00 +----~----+-----t----:::.0.~----+----~ .. G> ~ ~ 2 .00+---::.~+---=.,.C:....--t-----=..,_==---+--~~-t----~ .~ I l oo ,...__,_~+----t----t-----+-=--=---i~..,.....-----l 0 I&. • 0.00 .,.. ___ ..,_ ___ ..... ___ ..... ___ ...., ___ ...., _____ _ 0 5 10 15 20 25 Time (Minutes) ---Pre-De v elopment Hydrograph ---Post -Development Outfl ow Hyd rograph Without De t ention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 30 7 .00----~---~---~---~---~--~ ~ ~ 6.00 8 0 5.00 +-----+--~-t------'31...i::-----t----t-----i ; ~ 4.00 +-----+-::i~--+----+----=--=--+----i------i ~ ~ 3.00 +----7'11f----::7' ...... -=:::---+-----'l""oo-=-----+------f s::; Q. ~ 1 2.00 c I&. 1.00 +-..,...-:::ll""'c;_-+-----+----+----+----=:=o........,::1--3oio.::::----f 0.00..-.-----+------+------+------..,_ ____ __., ____ ~ ... 0 5 10 15 20 25 Time (Minutes) ---Pre -Dev elopment Hydrograph ---Po st -Deve lo pment Outfl ow Hy d rograph Without De t enti on 30 l 8.00 7.00 ~ 'g 6.00 ::;, 0 5.00 g ~ 4.00 ~. 3.00 _g A. 2.00 j l.00 Q 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 50-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 ---Pre-Development Hydrograph ---Post-Development Outflow Hydrograph Without Detention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 100-Year Storm Event -8.00 ------,-----r-----r-----r------,-------, i 7 .00 +----+----~--=::11-----+----+-----+-------l .Y 1' 6 .00 .g 5 5.oo +-----+-~---+-----+--31"'-::---+-----+---~ g ~ 4.00 ..._--~---+-----+---~--~~-__.j & ... 3.00 +--~L-+--___,.,.e:...__.._--=--=--+------+---"-----+----~ ... G> _g A. 2.00 +--~-...,...i:::..._---+-----+----=::o....~----=3io,1.,----~ .~ 1.00 +-:,~,,.c;.--+----+-----l----+-___;~....i.::--3oo-~ Q 0.00 ~--_. ___ ...... ___ ...._ __ ......, ___ ....,.._..;;::at 0 5 10 15 20 25 Time (Minutes) Pre-De velopment Hydrograph ---Post-Development Outflow Hydrograph Without Detention 30 12.00 "--~ Elevation Depth Volume (Feet) (Ft3) 293.59 0.00 0 294 .05 0.46 141 294.55 0.96 536 295 .00 1.41 1,216 296.00 2.41 2,726 296.68 3 .09 3,753 Detention Pond Depth Vs. Volume & 1.50 ..... ---+----+--7'--+---+----+----1-------1------l 0 500 l .000 l .500 2 .000 2 .500 3 ,000 3 .500 4 .000 Detention Pond Volume (Cubic Feet) Ra De 3.50 3.00 2.50 i 2.00 u.. -i 0 1.50 l.00 0 .50 0 .00 Weir Length(L): 0.25 (3 ") Elevation Depth Discharge (Feet) Ft3/Sec 293.59 0 .00 0.00 294 .05 0.46 0.23 294 .55 0.96 0.71 295 .00 1.41 1.26 296.00 2.41 2 .81 296 .68 3 .09 4.07 Rating Curve For Outlet Control Structure Depth Vs. Volume ,.,,, v v / / v , ..... / / / I I 0 .00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4 .50 Discharge (Cubic Feet Per Second) 4.50 ~ 4.00 5 ~ 3.50 l 3.00 i 2.50 0 :g 2.00 ~ G> 1.50 ~ J: 1.00 ~ Ci Depth (Feet) 0 .00 0.46 0.96 1.41 2.41 3 .09 / ~ 0.50 v 0.00 0 .00 20.00 Storage Discharge 2s/t 2s/t+O (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0 0.00 0 .00 0.00 141 0.23 4.72 4 .95 536 0.71 17.88 18.59 1,216 1.26 40.53 41.79 2,726 2.81 90 .86 93.67 3,753 4 .07 125.09 129.17 Storage Indication Curve ~ -""' "' v / / ..... / ~ ~ ,,,,,, 40 .00 60.00 80.00 100 .00 120 .00 140 .00 2s/t+O (Cubic Feet Per Second) Inflow I Outflow Simulation 2-Year Storm Event TI me Inflow 11+ 12 2s/t-0 2slt+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 293 .59 0.00 1 0.38 0 .38 0 .34 0 .38 0 .02 0 .08 293.67 0 .87 2 0 .76 1.14 1.35 1.49 0 .07 0.21 293.80 1.36 3 1.14 1.90 2.94 3 .25 0 .15 0.35 293 .94 1.77 4 1.52 2.66 5 .09 5 .61 0 .26 0.49 294.08 2.10 5 1.90 3.43 7 .81 8.52 0 .36 0.61 294 .20 2.34 6 2.28 4.19 11 .04 11.99 0.48 0.74 294 .33 2.58 7 2.66 4 .95 14.76 15.99 0 .62 0 .88 294.47 2.81 8 3 .05 5.71 18.97 20.47 0 .75 1.00 294.59 3.00 9 3.43 6.47 23.70 25 .44 0.87 1.10 294.69 3 .15 10 3 .81 7 .23 28.94 30.94 1.00 1.21 294.80 3.30 11 3 .62 7.42 34.11 36 .36 1.13 1.31 294.90 3 .44 12 3 .43 7 .04 38.67 41 .15 1.24 1.40 294.99 3 .55 13 3 .24 6 .66 42 .61 45 .33 1.36 1.49 295.08 3 .66 14 3 .05 6 .28 45.96 48.89 1.47 1.56 295 .15 3 .75 15 2.86 5 .90 48.74 51.86 1.56 1.63 295.22 3 .83 16 2.66 5.52 51 .01 54 .26 1.63 1.68 295.27 3.88 17 2.47 5.14 52.78 56.15 1.68 1.72 295.31 3 .93 18 2.28 4 .76 54 .08 57 .54 1.73 1.74 295.33 3 .96 19 2.09 4.38 54 .95 58 .46 1.75 1.76 295.35 3 .98 20 1.90 4 .00 55.41 58 .95 1.77 1.77 295.36 3 .99 21 1.71 3 .62 55.49 59 .03 1.77 1.77 295.36 3 .99 22 1.52 3 .24 55 .20 58 .73 1.76 1.77 295.36 3 .99 23 1.33 2.86 54 .57 58 .06 1.74 1.75 295 .34 3.97 24 1.14 2.47 53 .62 57 .05 1.71 1.73 295 .32 3.95 25 0.95 2.09 52 .37 55 .72 1.67 1.71 295 .30 3 .92 26 0 .76 1.71 50 .84 54 .09 1.62 1.67 295.26 3 .88 27 0 .57 1.33 49 .04 52.17 1.57 1.63 295.22 3 .83 28 0 .38 0.95 46 .99 49 .99 1.50 1.59 295.18 3 .78 29 0 .19 0 .57 44 .71 47.56 . 1.43 1.54 295.13 3 .72 30 0 .00 0.19 42 .20 44.90 1.35 1.48 295.07 3.65 Inflow/Outflow Simulation 2-Year Storm Event 4.50 4 .00 3.50 I I ....... "O c I I I 0 j 3.00 ... I I G> a.. 2.50 1 u.. I (.) I ~ 2.00 :I I • I I I ~ ~ 1.50 ~ 0 1.00 I I 0.50 -· 0.00 0 5 ----Pre-- -• • Devel opme nt Hydr og raph ... I .... I .... .... .... ' .... .... .... .... ' ... .... ' ' .... ... -· ·-· ...... -.. ·---. -. ·-·-·--·-- 10 15 20 Time (Minutes) Post- De velopme nt Outflow Hy drograph Without Detenti on ----Post- Deve lo pme nt Outflow Wit h Detention 25 30 -· -· -· Post- Develop m e nt 'Fre e- Flow' Inflow I Outflow Simulation 5-Year Storm Event TI me Inflow 11+ 12 2s/t-O 2slt+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.59 0.00 1 0.46 0.46 0.42 0.46 0.02 0.09 293.68 0.92 2 0.93 1.39 1.64 1.81 0.09 0.24 293.83 1.45 3 1.39 2.31 3.58 3.95 0.19 0.40 293.99 1.89 4 1.85 3.24 6.22 6.82 0.30 0.54 294.13 2.21 5 2.31 4.17 9.54 10.39 0.42 0.68 294.27 2.48 6 2.78 5.09 13.50 14.64 0.57 0.83 294.42 2.74 7 3.24 6.02 18.06 19.52 0.73 0.98 294.57 2.97 8 3.70 6.94 23.29 25.01 0.86 1.09 294.68 3.14 9 4.17 7.87 29.15 31.16 1.00 1.21 294.80 3.31 10 4.63 8.80 35.62 37.95 1.16 1.34 294.93 3.47 11 4.40 9.03 41.96 44.65 1.34 1.47 295.06 3.64 12 4.17 8.56 47.49 50.53 1.52 1.60 295.19 3.79 13 3.93 8.10 52.26 55.60 1.67 1.70 295.29 3.92 14 3.70 7.64 56.30 59.90 1.80 1.79 295.38 4.01 15 3.47 7.18 59.67 63.48 1.90 1.86 295.45 4.09 16 3.24 6.71 62.40 66.38 1.99 1.92 295.51 4.15 17 3.01 6.25 64.54 68.65 2.06 1.96 295.55 4.20 18 2.78 5.79 66.11 70.32 2.11 1.99 295.58 4.23 19 2.55 5.32 67.15 71.43 2.14 2.01 295.60 4.26 20 2.31 4.86 67.69 72.01 2.16 2.02 295.61 4.27 21 2.08 4.40 67.77 72.09 2.16 2.02 295.61 4.27 22 1.85 3.93 67.40 71.70 2.15 2.02 295.61 4.26 23 1.62 3.47 66.62 70.87 2.12 2.00 295.59 4.24 24 1.39 3.01 65.46 69.63 2.09 1.98 295.57 4.22 25 1.16 2.55 63.93 68.00 2.04 1.95 295.54 4.19 26 0.93 2.08 62.05 66.01 1.98 1.91 295.50 4.15 27 0.69 1.62 59.85 63.67 1.91 1.86 295.45 4.10 28 0.46 1.16 57.35 61.01 1.83 1.81 295.40 4.04 29 0.23 0.69 54.56 58.04 1.74 1.75 295.34 3.97 30 0.00 0.23 51.50 54.79 1.64 1.69 295.28 3.90 lnflow/OuHlow Simulation 5-Year Storm Event 5 .00 ' I ~ • ' ' I • -'O 4 .00 I ' c I 0 ~ I ' I ' .. I ' G> ' A. 3 .00 1 I ' ' ~ 0 I ' ~ 2.00 :J ' 0 -I ' ~ • ~ I 1.00 I 0 I . . . . . .......... -......... . ......... 0 .00 -1 .00 nme (Minutes) Pre-. . . . Post -Post -. ....... Post - Developm e Deve lopme Developm e Developme nt nt Outflow nt Outflo'.'.' nt "Fre e- Hydrograph Hydrogr a ph Wit h Fl ow" Without Detention Detention Inflow I Outflow Simulation 10-Year Storm Event nme Inflow 11+ 12 2s/t-O 2slt+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.59 0.00 1 0.52 0.52 0.47 0.52 0.02 0.10 293.69 0.96 2 1.04 1.56 1.84 2.03 0.10 0.25 293.84 1.51 3 1.56 2.60 4.02 4.44 0.21 0.43 294.02 1.96 4 2.08 3.64 7.00 7.65 0.33 0.58 294.17 2.28 5 2.60 4.68 10.74 11.67 0.47 0.73 294.32 2.56 6 3.12 5.72 15.19 16.46 0.63 0.89 294.48 2.83 7 3.64 6.75 20.38 21.95 0.79 1.03 294.62 3.05 8 4.16 7.79 26.31 28.17 0.93 1.16 294.75 3.23 9 4.68 8.83 32.94 35.14 1.10 1.29 294.88 3.41 10 5.20 9.87 40.24 42.82 1.29 1.43 295.02 3.59 11 4.94 10.13 47.35 50.38 1.51 1.60 295.19 3.79 12 4.68 9.61 53.55 56.96 1.71 1.73 295.32 3.95 13 4.42 9.09 58.88 62.64 1.88 1.84 295.43 4.07 14 4.16 8.57 63.41 67.45 2.02 1.94 295.53 4.18 15 3.90 8.05 67.18 71.46 2.14 2.01 295.60 4.26 16 3.64 7.53 70.23 74.71 2.24 2.07 295.66 4.32 17 3.38 7.01 72.62 77.25 2.32 2.12 295.71 4.37 18 3.12 6.50 74.37 79.11 2.37 2.15 295.74 4.40 19 2.86 5.98 75.53 80.35 2.41 2.18 295.77 4.43 20 2.60 5.46 76.13 80.99 2.43 2.19 295.78 4.44 21 2.34 4.94 76.21 81.07 2.43 2.19 295.78 . 4.44 22 2.08 4.42 75.79 80.63 2.42 2.18 295.77 4.43 23 1.82 3.90 74.91 79.69 2.39 2.16 295.75 4.41 24 1.56 3.38 73.60 78.29 2.35 2.14 295.73 4.39 25 1.30 2.86 71.87 76.46 2.29 2.11 295.70 4.35 26 1.04 2.34 69.76 74.21 2.22 2.06 295.65 4.31 27 0.78 1.82 67.29 71.58 2.15 2.02 295.61 4.26 28 0.52 1.30 64.47 68.59 2.06 1.96 295.55 4.20 29 0.26 0.78 61.34 65.25 1.96 1.90 295.49 4.13 30 0.00 0.26 57.90 61.60 1.85 1.82 295.41 4.05 Inflow/Outflow Simulation 10-Year Storm Event 6.00 I ' I • I ' ... 5.00 I ' I ' I ' I ' I -' ,, 4.00 I c I 0 ' ~ I ' I ' ... G> I ' CL I ' l I ' 3.00 ' """ ' 0 ~ I ' :;::, (.) I .. -~ I 0 I =§ I ' 2.00 0 I I ' I ' I I ' • ' 1.00 ' ' I ' ' . . . . . . .......... . .... . . . .. ....... . ........ .. .......... .. .. .. .. 0.00 0 5 10 15 20 25 30 nme (Minutes) Pre-. . . . Post -Post-........... Post- De velo p me Developme De velopm e Developm e nt nt O utflow nt Outflow nt "Fre e- Hydr ograph Hydrograph Wit h Flow" Without Det ention Detention Inflow I Outflow Simulation 25-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.59 0.00 1 0.59 0.59 0.54 0.59 0.03 0.11 293.70 1.00 2 1.19 1.78 2.10 2.32 0.11 0.28 293.87 1.58 3 1.78 2.97 4.59 5.07 0.24 0.47 294.06 2.05 4 2.37 4.15 8.01 8.74 0.37 0.62 294.21 2.36 5 2.97 5.34 12.31 13.35 0.52 0.79 294.38 2.66 6 3.56 6.53 17.41 18.83 0.71 0.97 294.56 2.95 7 4.15 7.71 23.40 25.13 0.86 1.10 294.69 3.14 8 4.75 8.90 30.24 32.31 1.03 1.24 294.83 3.34 9 5.34 10.09 37.89 40.33 1.22 1.38 294.97 3.53 10 5.93 11.28 46.21 49.17 1.48 1.57 295.16 3.76 11 5.64 11.57 54.32 57.79 1.73 1.75 295.34 3.97 12 5.34 10.98 61.38 65.30 1.96 1.90 295.49 4.13 13 5.04 10.39 67.46 71.77 2.15 2.02 295.61 4.26 14 4.75 9.79 72.62 77.25 2.32 2.12 295.71 4.37 15 4.45 9.20 76.92 81.82 2.45 2.20 295.79 4.45 16 4.15 8.60 80.40 85.52 2.56 2.27 295.86 4.52 17 3.86 8.01 83.11 88.41 2.65 2.32 295.91 4.57 18 3.56 7.42 85.10 90.53 2.71 2.36 295.95 4.60 19 3.26 6.82 86.42 91.93 2.75 2.38 295.97 4.63 20 2.97 6.23 87.10 92.65 2.78 2.39 295.98 4.64 21 2.67 5.64 87.18 92.74 2.78 2.39 295.98 4.64 22 2.37 5.04 86.70 92.23 2.76 2.39 295.98 4.63 23 2.08 4.45 85.69 91.15 2.73 2.37 295.96 4.62 24 1.78 3.86 84.18 89.55 2.68 2.34 295.93 4.59 25 1.48 3.26 82.21 87.45 2.62 2.30 295.89 4.55 26 1.19 2.67 79.79 84.88 2.54 2.26 295.85 4.51 27 0.89 2.08 76.96 81.87 2.45 2.20 295.79 4.45 28 0.59 1.48 73.74 78.44 2.35 2.14 295.73 4.39 29 0.30 0.89 70.16 74.63 2.24 2.07 295.66 4.32 30 0.00 0.30 66.23 70.45 2.11 1.99 295.58 4.24 Inflow/Outflow Simulation .25-Year Storm Event 7.00 Inflow I Outflow Simulation 50-Year Storm £;vent Time Inflow 11+ 12 2s/t-0 2slt+O Outflow Depth Elevation Velocity {Minutes) {Ft3/Sec) {Ft3/Sec) {Feet) {Ft/Sec) 0 0 .00 0.00 0 .00 0.00 0 .00 0.00 293 .59 0.00 1 0.67 0.67 0 .61 0.67 0.03 0.12 293.71 1.05 2 1.34 2.01 2.37 2.62 0 .12 0 .30 293 .89 1.65 3 2.01 3 .35 5 .20 5 .73 0.26 0.49 294.08 2 .11 4 2.68 4.70 9.09 9.90 0 .41 0 .66 294.25 2.44 5 3 .35 6.04 13.96 15 .13 0 .59 0 .85 294.44 2.76 6 4 .03 7 .38 19 .79 21 .34 0 .77 1.02 294.61 3 .03 7 4 .70 8.72 26.63 28 .51 0 .94 1.16 294.75 3 .24 8 5 .37 10.06 34.43 36.70 1.13 1.32 294.91 3 .44 9 6 .04 11 .40 43.08 45 .83 1.38 1.50 295.09 3 .67 10 6.71 12.75 52 .47 55 .82 1.68 1.71 295.30 3 .92 11 6.37 13.08 61 .62 65 .55 1.97 1.90 295.49 4 .14 12 6.04 12.41 69.59 74 .03 2.22 2.06 295.65 4.31 13 5 .70 11 .74 76.46 81.33 2.44 2.19 295.78 4.44 14 5.37 11 .07 82.28 87.53 2.62 2.30 295.89 4.55 15 5 .03 10.40 87 .13 92 .68 2.78 2 .39 295.98 4.64 16 4 .70 9.73 91 .02 96.86 2.92 2.47 296.06 4 .72 17 4 .36 9.06 94 .00 100.07 3 .03 2.54 296.13 4 .78 18 4 .03 8.39 96.15 102.39 3.12 2.59 296.18 4.82 19 3.69 7 .71 97.53 103.87 3.17 2.61 296 .20 4.85 20 3 .35 7 .04 98 .18 104.57 3.20 2 .63 296.22 4 .86 21 3.02 6.37 98.16 104.55 3.19 2.63 296.22 4 .86 22 2 .68 5 .70 97.53 103.87 3 .17 2.61 296 .20 4.85 23 2 .35 5.03 96.31 102.56 3.12 2.59 296.18 4 .83 24 2 .01 4.36 94 .56 100.67 3 .06 2.55 296.14 4 .79 25 1.68 3 .69 92 .31 98 .25 2 .97 2.50 296.09 4.75 26 1.34 3 .02 89 .60 95 .33 2 .87 2.44 296.03 4 .69 27 1.01 2.35 86.44 91.95 2.75 2.38 295.97 4.63 28 0.67 1.68 82 .83 88 .11 2.64 2.31 295.90 4.56 29 0.34 1.01 78.82 83.84 2.51 2.24 295.83 4.49 30 0.00 0.34 74.41 79 .15 2.37 2.15 295.74 4 .40 t8' g 8 .00 7.00 6.00 ~ 5 .00 i 1 ~ 4.00 0 1i :;:, ~ ~ 3 .00 ~ 0 2.00 1.00 0 .00 0 lnflow/Outfl()w Simulation 50-Year Storm Event I I I I Pre- I I I • I I I I Developme nt Hydrograph 5 . I I • I • I I I I ' I I I I ' ... ' ' ' ' -. . . .... . . -..... . . . 10 ' ' ' ' ' ' ' ' ' .. ..... . ...... .. .... 15 20 Time (Minutes) • . . Post -Post- Developme Developme nt Outflow nt Outflow Hydrograph With Without Detention Detention ' .. .. . .. . .. 25 . ....... ' ... ' 30 Post - Developme nt "Free- Flow· Inflow I Outflow Simulation 100-Year Storm Event TI me Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevat ion Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0 .00 0.00 0 .00 0 .00 293.59 0 .00 1 0 .70 0 .70 0 .63 0 .70 0 .03 0 .12 293 .71 1.06 2 1.40 2.10 2 .48 2 .74 0 .13 0 .31 293 .90 1 .67 3 2 .10 3 .50 5 .44 5.98 0 .27 0.51 294.10 2 .13 4 2.80 4 .90 9.50 10.34 0.42 0.68 294.27 2 .47 5 3 .50 6 .30 14.59 15.81 0 .61 0 .87 294.46 2.80 6 4.20 7 .70 20 .70 22 .29 0 .79 1 .04 294 .63 3.06 7 4.90 9.11 27 .87 29 .81 0 .97 1 .19 294.78 3.27 8 5 .60 10.51 36 .02 38.37 1.17 1 .35 294 .94 3.48 9 6 .30 11.91 45 .05 47.93 1 .44 1.54 295.13 3 .73 10 7 .00 13.31 54 .86 58.36 1.75 1.76 295.35 3 .98 11 6 .65 13.66 64.41 68.52 2 .05 1.96 295 .55 4.20 12 6.30 12.96 72 .73 77 .37 2 .32 2 .12 295 .71 4.37 13 5.95 12 .26 79 .89 84 .98 2 .55 2 .26 295 .85 4 .51 14 5 .60 11 .56 85 .97 91.45 2 .74 2 .37 295 .96 4.62 15 5 .25 10.86 90 .99 96 .83 2 .92 2.47 296.06 4.72 16 4.90 10.16 95 .00 101 .14 3 .07 2.56 296.15 4.80 17 4 .55 9.46 98 .07 104.45 3.19 2.63 296 .22 4 .86 18 4 .20 8 .76 100.28 106.83 3 .28 2.67 296 .26 4.90 19 3 .85 8 .05 101 .67 108.33 3 .33 2.70 296.29 4.93 20 3 .50 7 .35 102 .32 109 .03 3 .35 2 .71 296 .30 4 .94 21 3 .1 5 6.65 102 .27 108.97 3 .35 2.71 296.30 4 .94 22 2.80 5 .95 101 .57 108.22 3.33 2.70 296.29 4.93 23 2 .45 5 .25 100.27 106 .82 3 .28 2 .67 296.26 4 .90 24 2 .10 4 .55 98.41 104 .82 3 .20 2 .63 296 .22 4.87 25 1 .75 3 .85 96 .04 102 .27 3 .11 2 .58 296 .17 4.82 26 1.40 3 .15 93 .19 99 .19 3 .00 2 .52 296 .11 4 .76 27 1 .05 2.45 89 .88 95 .64 2 .88 2.45 296 .04 4 .70 28 0.70 1.75 86 .15 91 .64 2 .75 2 .38 295 .97 4.62 29 0 .35 1.05 81 .97 87 .20 2.61 2 .30 295.89 4.55 30 0 .00 0 .35 77 .39 82 .32 2.47 2.21 295.80 4.46 Inflow/Outflow Simulation 100-Year Storm Event 8.00 ' I ' I ' 7.00 I I ' ' I ' I ' 6.00 • ' I ' I -' ,, I c I • 0 ' ~ 5.00 I ' ~ I ' Q. I ' i I ' 4.00 ' ~ 0 ' ~ I :J ~ I ~ I 0 3.00 !§ I ' ' 0 I ' I ' I ' 2.00 I I ' I ... I ' 1.00 I ' . . . ... . .... . . . . . . . .... . ..... . ...... .. .. . . . ... 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post -........ Post- Developme Deve lopme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydr ograph Hydrograph With Flow · Wit hout Detentio n Detention Inflow/Outflow Simulation 2-Year Storm Event 1.40 -'O c 0 ~ 1.20 ... ~ ~ l 1.00 I&. () J5 :::J ~ ~ 0 .80 0 ~ 0 0 .60 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---Total Post-Development Hydrograph Inflow/Outflow Simulation 5-Year Storm Event -,, c 0 ~ 1.50 • A. 1 .... 0 ~ :::J 0 -:I; 1.00 ~ 0 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---Total Post-Development Hydrograph Inflow/Outflow Simulation 10-Year Storm Event 3 .00 2 .50 ~ 2.00 c 0 ~ ... G> 0.. 1 1.50 u.. 0 :0 :I g ~ 0 =§ 0 1.00 0.50 0.00 0 5 10 15 20 25 30 nme (Minutes) ---Pre -Development Hydrograph ---Total Post-Development Hydrograph Inflow/Outflow Simulation 25-Year Storm Event 2 .50 -,, c 0 j ._ 2 .00 G> A. i Lr.. 0 :a :;, (.) 1.50 ...., ~ 0 !§ 0 1.00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---Total Post -Development Hydrograph Inflow/Outflow Simulation 50-Year Storm Event 3.00 'O c 0 2 .50 ~ ... Cl> A. l 2 .00 u.. 0 ~ ~ ~ ~ ~ 1.50 0 1.00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---•Total Post-Development Hydrograph Inflow/Outflow Simulation 100-Yeor Storm Event 3.00 ,... ~ 0 2.50 ~ 5 CL 1 2.00 u. 0 ~ :J ~ ~ ~ 1.50 0 1.00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrogroph ---Total Post-Development Hydrogroph 100% 80% 70% i 60% u.. 0 Zi ~ 50% 0 -~ ~ 40% 0 > 30% 20% 10% 0% Detention Pond Storage Volumes as Percent of Maximum Volume 2-year 5-year 10-year 25-year SO-year 100-year Design Storm Design Maximum Percentage Storm Depth Volume Volume of Maximum 2-year 1.77 1764 3 ,753 47% 5-year 2.02 2144 3 ,753 57% 10-year 2 .19 2393 3 ,753 64% 25 -year 2.39 2702 3 ,753 72% SO-year 2 .63 3055 3 ,753 81% 100-year 2 .71 3186 3 ,753 85% October 11 , 1994 Garrett Engineering CITY OF COi 1 .EGE STATION Post Office Box 9960 1101 Texas Avenue College Station, Texas 77842-9960 (409) 764-3500 4444 Carter Creek Blvd ., Suite 108 Bryan, TX 77802 Attn : Earl Havel RE: KFO Mini Storage Facility Improvement Plans Dear Earl, We have received and approved the Fire Hydrant plans for this site, however there were only 5 sets submitted, so you need to get 5 more to us for approval stamping . Once we receive and stamp all the plans , we will provide you with your sets . We have also approved your Erosion Control plans , and therefore need 10 sets for approval stamping . We received an application for a Drainage Development Permit, however no updated c~lculations were provided . According to my file notes, I spoke with you on April 15th of this year, and you advised me that the site was changing, and I need not review the report which had been submitted . Upon my review of the erosion control plans , I did notice that the plan has changed somewhat, so a new and/or revised report is required . Please get the plans and reports mentioned above to me as soon as possible and remember to call me should you have any questions . ~: BrettMcC~ Project Manager cc : vV eronica Morgan, Assistant City Engineer Shirley Volk, Development Coordinator Home of Texas A&M University DRAINAGE COMPUTATIONS For Lot 5, Block 1 K.F.O. Addition College Station, Brazos County, Texas / c ,,,,l. cu lA710?\...6 <!><:. C3 u I .--- ~ p41\V47G" O(::/C::~ll&-v /\../c;r /lc..lOr..VC'D I //V /?~(.,IC.-~ow. "'fO 5'/Jc-7-iA''-~~/ - 2) Pon.~.flJl'tc.. t),.C. 51P<:::-tvA-t.,K.. ~ ~ R~ //V ~/Vl'!.c-~ou'-J> f?Mrr:a~r ) C..O"'\J ~ I PC:::~72 O..Y /'f'T 7>/7..S £,. 0 C./f"i2 oV '3) c..o"'-'~u~ ~ s po+-~le.v.0,.-11.~s N~ (4e-v15,e....., J. CLA-'2.IFr~b .. "V ~ SHO'-V ' 1-1.::::.~ ?.::.--v.£> u;out..P coo""-"'?°).o11~ ;C'-o...v..s 4) Sc::~ £ .t-f (Ci..,~ A-oo1 ll~ G:,ntlfte,y{s rrfr Ga:::P:~:~n::;ing ~~11 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 *October, 1994 * Dete rmine To tal Pre -Developmen t Peak Storm Wate r Discharge Rates Tributary A rea ("A"): 0 .78 Acres Pervious Area : 0.78 Acres Impervious Area : 0.00 Acres Run-Off C oefficient ("Cwt"): 0.40 Time Of Concentrati o n ("T/c"): Wo odla nd s: Low Elevati on: High Elevati on: Dista nce (Feet): Slope (%Grade): Velocity ("Vw"): Time : Pa stu re s: Low Elevati on: High Elevation: Distance (Feet): Slope (% Grade): Velocity ("Vp"): Time : Pa veme nts: Low Elevation: High Ele vation : Distance (Feet): Slope (% Grade): Velocity ("Vpave "): Time : Total Travel Time: Hourly Inte nsity Rates ("I"): 2-Year: 6.33 5-Year: 7.69 10-Year: 8.63 25-Year: 9 .86 50-Year: 11.15 100-Year: 11.64 Peak Discharge Rate ("Q"): 2-Year: 1.99 5-Year: 2.42 10-Year: 2.72 25-Year: 3 .10 50-Year: 3.51 100-Year: 3.66 C= 0.40 C= 0.98 0.00 0 .00 0.00 0 .0 0 0 .00 0.00 0.00 0.00 0 .00 0 .00 0.00 0.00 0 .0 0 0 .00 0.00 0 .00 Feet I Seco nd M inutes Feet I Second Minutes 0.00 Feet I Second 0 .00 Minut es 10.00 Minutes Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Ho ur Inches I Hour Cubic Feet I Secon d Cubic Feet I Second Cubic Feet I Seco nd Cubic Feet I Secon d Cubic Feet I Secon d Cubic Feet I Seco nd Determine Post-development Peak Storm Water Dischar e No Detention Tributary Area ("A"): 0.78 Acres Pervious Area: 0 .12 Acres C= 0.40 C= 0.98 Impervious Area : 0.66 Acres Run-Off Coefficient ("Cwt"): 0 .89 Time Of Concentration ("Tic"): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 Inches I Hour 5-Year: 7.69 Inches I Hour 10-Year: 8.63 Inches I Hour 25-Year: 9 .86 Inches I Hour 50-Year: 11.15 Inches I Hour 100-Year: 11 .64 Inches I Hour Peak Discharge Rate ("Q"): 2-Year: 4 .43 Cubic Feet I Second 5-Year: 5.39 Cubic Feet I Second 10-Year: 6.05 Cubic Feet I Second 25-Year: 6.91 Cubic Feet I Second 50-Year: 7.81 Cubic Feet I Second 100-Year: 8 .15 Cubic Feet I Second Comparis on Of Predevelopment And Post-develo ment Peak Dischar e Rates Predevelopment Post-Development Increase 2-Year: 1.99 Ft3/sec 4.43 Ft3/sec 2.44 Ft3/sec 5-Year: 2.42 Ft3/sec 5.39 Ft3/sec 2.97 Ft3/sec 10-Year: 2.72 Ft3/sec 6 .05 Ft3/sec 3 .33 Ft3/sec 25-Year: 3.1 O Ft3/sec 6.91 Ft3/sec 3.81 Ft3/sec 50-Year: 3 .51 Ft3/sec 7.81 Ft3/sec 4.30 Ft3/sec 100-Year: 3 .66 Ft3/sec 8.15 Ft3/sec 4.49 Ft3/sec Preliminary Determination Of Detenti on Pond Volume -~-~ 2-Year: 2.44 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 2,198 Cubic Feet 5-Year: 2 .97 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 2,672 Cubic Feet 10-Year: 3 .33 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 3,000 Cubic Feet 25-Year: 3.81 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 3,426 Cubic Feet 50-Year: 4 .30 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 3,873 Cubic Feet 100-Year: 4.49 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 4,043 Cubic Feet Determine Post-Development 11 Free-Flow 11 Peak Storm Water Discharge Tributary Area ("A"): 0 .05 Acres Pervious Area : 0.01 Acres Impervious Area : 0 .04 Acres Run-Off Coefficient ("Cwt"): 0 .86 Time Of Concentration ("Tic"): 1 O Minutes (Min ) Hourly Intensity Rates ("I"): 2-Year: 6 .33 5-Year: 7 .69 10-Year: 8 .63 25-Year: 9.86 50-Year: 11.15 100-Year: 11.64 Peak Discharge Rate ("Q"): 2-Year: 0.28 5-Year: 0 .34 10 -Y ear: 0 .38 25-Year: 0.43 50-Year: 0.49 100-Year: 0 .51 c = 0.40 C= 0 .98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post-Development Flow Into Detention Pond Tributary Area ("A "): 0.73 Acres Perv ious Area : 0.11 Acres Impervious Area : 0.62 Acres Run-Off Coefficient ("Cwt"): 0 .89 Time Of Concentration ("T/c "): 1 O M inutes (M in) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7 .69 10-Year: 8.63 25 -Year: 9.86 50-Year: 11 .15 100-Year: 11.64 Peak Discharge Rate ("Q "): 2-Year: 4.16 5-Year: 5.05 10 -Year: 5 .67 25-Year: 6.48 50-Year: 7.32 100-Year: 7 .65 c = 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Pre-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year {Minutes} Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.20 0.24 0.27 0.31 0.35 0.37 2 0.40 0.48 0.54 0.62 0.70 0.73 3 0.60 0.73 0.81 0.93 1.05 1.10 4 0.80 0.97 1.09 1.24 1.40 1.46 5 1.00 1.21 1.36 1.55 1.75 1.83 6 1.19 1.45 1.63 1.86 2.10 2.20 7 1.39 1.69 1.90 2.17 2.45 2.56 8 1.59 1.94 2.17 2.48 2.81 2.93 9 1.79 2.18 2.44 2.79 3.16 3.30 Peak=> L 10 1.99 2.42 ' 2.72 3.10 . 3.51 3.66 11 1.89 2.30 2.58 2.95 3.33 3.48 12 1.79 2.18 2.44 2.79 3.16 3.30 13 1.69 2.06 2.31 2.64 2.98 3.11 14 1.59 1.94 2.17 2.48 2.81 2.93 15 1.49 1.82 2.04 2.33 2.63 2.75 16 1.39 1.69 1.90 2.17 2.45 2.56 17 1.29 1.57 1.77 2.02 2.28 2.38 18 1.19 1.45 1.63 1.86 2.10 2.20 19 1.09 1.33 1.49 1.71 1.93 2.01 20 1.00 1.21 1.36 1.55 1.75 1.83 21 0.90 1.09 1.22 1.40 1.58 1.65 22 0.80 0.97 1.09 1.24 1.40 1.46 23 0.70 0.85 0.95 1.09 1.23 1.28 24 0.60 0.73 0.81 0.93 1.05 1.10 25 0.50 0.61 0.68 0.78 0.88 0.92 26 0.40 0.48 0.54 0.62 0.70 0.73 27 0.30 0.36 0.41 0.47 0.53 0.55 28 0.20 0.24 0.27 0.31 0.35 0.37 29 0.10 0.12 0.14 0.16 0.18 0.18 30 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.44 0.54 0.60 0.69 0.78 0.82 2 0.89 1.08 1.21 1.38 1.56 1.63 3 1.33 1.62 1.81 2.07 2.34 2.45 4 1.77 2.16 2.42 2.76 3.12 3.26 5 2.22 2.69 3.02 3.45 3.90 4.08 6 2.66 3.23 3.63 4.15 4.69 4.89 7 3.10 3.77 4.23 4.84 5.47 5.71 8 3.55 4.31 4.84 5.53 6.25 6.52 9 3.99 4.85 5.44 6.22 7.03 7.34 l -Peak=> 10 u.4.43 --5.39 -6.Q.5 __ 6.91 fl 7.81 8.15 11 4.21 5.12 5.75 6.56 7.42 7.75 12 3.99 4.85 5.44 6.22 7.03 7.34 13 3.77 4.58 5.14 5.87 6.64 6.93 14 3.55 4.31 4.84 5.53 6.25 6.52 15 3.32 4.04 4.54 5.18 5.86 6.12 16 3.10 3.77 4.23 4.84 5.47 5.71 17 2.88 3.50 3.93 4.49 5.08 5.30 18 2.66 3.23 3.63 4.15 4.69 4.89 19 2.44 2.96 3.33 3.80 4.30 4.48 20 2.22 2.69 3.02 3.45 3.90 4.08 21 1.99 2.43 2.72 3.11 3.51 3.67 22 1.77 2.16 2.42 2.76 3.12 3.26 23 1.55 1.89 2.12 2.42 2.73 2.85 24 1.33 1.62 1.81 2.07 2.34 2.45 25 1.11 1.35 1.51 1.73 1.95 2.04 26 0.89 1.08 1.21 1.38 1.56 1.63 27 0.66 0.81 0.91 1.04 1.17 1.22 28 0.44 0.54 0.60 0.69 0.78 0.82 29 0.22 0.27 0.30 0.35 0.39 0.41 30 0.00 0.00 0.00 0.00 0.00 0.00 Post-Development Flow Routed Through Detention Pond Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.42 0.51 0.57 0.65 0.73 0.76 2 0.83 1.01 1.13 1.30 1.46 1.53 3 1.25 1.52 1.70 1.94 2.20 2.29 4 1.66 2.02 2.27 2.59 2.93 3.06 5 2.08 2.53 2.84 3.24 3.66 3.82 6 2.49 3.03 3.40 3.89 4.39 4.59 7 2.91 3.54 3.97 4.54 5.13 5.35 8 3.33 4.04 4.54 5.18 5.86 6.12 9 3.74 4.55 5.11 5.83 6.59 6.88 Peak=> r: 10 4.16 5.05 5.67 6.48 7.32 7.65 11 3.95 4.80 5.39 6.16 6.96 7.26 12 3.74 4.55 5.11 5.83 6.59 6.88 13 3.53 4.30 4.82 5.51 6.23 6.50 14 3.33 4.04 4.54 5.18 5.86 6.12 15 3.12 3.79 4.25 4.86 5.49 5.74 16 2.91 3.54 3.97 4.54 5.13 5.35 17 2.70 3.29 3.69 4.21 4.76 4.97 18 2.49 3.03 3.40 3.89 4.39 4.59 19 2.29 2.78 3.12 3.56 4.03 4.21 20 2.08 2.53 2.84 3.24 3.66 3.82 21 1.87 2.27 2.55 2.92 3.30 3.44 22 1.66 2.02 2.27 2.59 2.93 3.06 23 1.45 1.77 1.99 2.27 2.56 2.68 24 1.25 1.52 1.70 1.94 2.20 2.29 25 1.04 1.26 1.42 1.62 1.83 1.91 26 0.83 1.01 1.13 1.30 1.46 1.53 27 0.62 0.76 0.85 0.97 1.10 1.15 28 0.42 0.51 0.57 0.65 0.73 0.76 29 0.21 0.25 0.28 0.32 0.37 0.38 30 0.00 0.00 0.00 0.00 0.00 0.00 ' Post-Development "Free-Flow" Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.03 0.03 0.04 0.04 0.05 0.05 2 0.06 0.07 0.08 0.09 0.10 0.10 3 0.08 0.10 0.11 0.13 0.15 0.15 4 0.11 0.13 0.15 0.17 0.19 0.20 5 0.14 0.17 0.19 0.21 0.24 0.25 6 0.17 0.20 0.23 0.26 0.29 0.30 7 0.19 0.23 0.26 0.30 0.34 0.35 8 0.22 0.27 0.30 0.34 0.39 0.41 9 0.25 0.30 0.34 0.39 0.44 0.46 Peak=> 1 · 10 0.28 oa 0.38 0.43 0.49 0.5j 11 0.26 0.32 0.36 0.41 0.46 0.48 12 0.25 0.30 0.34 0.39 0.44 0.46 13 0.23 0.28 0.32 0.37 0.41 0.43 14 0.22 0.27 0.30 0.34 0.39 0.41 15 0.21 0.25 0.28 0.32 0.36 0.38 16 0.19 0.23 0.26 0.30 0.34 0.35 17 0.18 0.22 0.24 0.28 0.32 0.33 18 0.17 0.20 0.23 0.26 0.29 0.30 19 0.15 0.18 0.21 0.24 0.27 0.28 20 0.14 0.17 0.19 0.21 0.24 0.25 21 0.12 0.15 0.17 0.19 0.22 0.23 22 0.11 0.13 0.15 0.17 0.19 0.20 + 23 0.10 0.12 0.13 0.15 0.17 0.18 24 0.08 0.10 0.11 0.13 0.15 0.15 25 0.07 0.08 0.09 0.11 0.12 0.13 26 0.06 0.07 0.08 0.09 0.10 0.10 27 0.04 0.05 0.06 0.06 0.07 0.08 28 0.03 0.03 0.04 0.04 0.05 0.05 29 0.01 0.02 0.02 0.02 0.02 0.03 30 0.00 0.00 0.00 0.00 0.00 0.00 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 2-Year Storm Event 4.50 ..----,----------,a;:-----.-----r-----,--------, l 4.00 +-----+----I--+-~---+----+-----+------! ~ 3.50+----+--~-+---~d-----+-----+----l 0 ....... :c -g 3.00 +----+-~'----+-----+-2';:----+-----+----l 8 8 2.50 +----~'----+-----+---~:-+-----+----j ...._. G> G> Cl) 2.00 +---~q---___,,......=----+-----+-.......,.----+------1 O> ... 0 :. 1.50 ~ 1.00 +--~~~f£--------+----t----=-+-=---~.,-------I 0 0 .50+-.~.,,,,.C---+-----+-----+-----+----==-+-o=--"""oc:----1 o.oo~----e----+---+------41-------+--..;;;;;::;ii~ 0 5 10 15 20 25 30 nme (Minutes) ---Pre-Development Hydrograph ---Total Po st-Development Hydrograph Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event 1.00 +--~--=~+----+-----+-----t==""-=---lf-..3o-----I 0.00...-.----t----+---+---~1------+--;;;;;::;JI~ 0 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph ---Post-Development Outflow Hydrograph Without Detention 30 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Event 7.00 ----~---~---~---~-----.-------. .2 u 6.00 +----+-------:;.....,:----+----+-----t-------t Jl c 8 0 5.00 +-----t--~~-t----::!llo-...:--f-----+-----t-----l ; ~ 4 .00 +----+---7"---+----+-~=---+-----t-------t 0) ... 0 t. 3.00 ~ -2.00+--~~-t--::;;io~--t----==-+-==----+----::!llo-...:--t-----l .~ $ l 00 +----:F-.~'-t----t----+----+--=--=-1--"'""-...:----i 0 ~ . 0.00 ,liiE:::... _ _._ __ _._ __ _. ___ ..._ __ ...__:;::::::::=~ 0 5 10 15 20 25 Time (Minutes) ---Pre-Development Hydrograph ---Post-Development Outflow Hydrograph Witho ut Detention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 30 7 .00 ----.-----:a;;;:----.-----.-----.------, .2 u 6.00 +----+----,~+---".....,.-+----+----+-----I Jl c 8 0 5.00 ........ 0 CD ~ 4.00 +------+-#----t----t---""'°""":-+-----+-------l ~ a; 3.00 +---~-l-----:7'"1'"-....::;::----l-----+-"'""""'='---+-----l ~ Q. ~ Q) 2 .00 ·-CD l 00 +-F--7""'""'----1-----+----+-----t---="""""'"""""'::l-~~--l 0 ~ . 0 .00 4SO----+---..... --__ .,_ __ ....., ___ .._ _ _,;;;=-t 0 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph ---Post-Development Outflow Hyd rograp h Without Detention 30 l 8 .00 7.00 LI.. .~ B 6.00 .g s 5.00 ~~ 4.00 & ... 3.00 ... G> 0 0.. 2 .00 .&:. &t 1.00 0 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 50-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 ---Pre -Development Hydrograph ---Post-Development Outflow Hydrograph Without Detention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 100-Year Storm Event -9.00-----~---~---~----~---~---~ * 8 .00 -----+----~------t----+------+------i ~ ..... 7.00 +-----+---~-+----::31"-:::---t----+-----+-----l ·-"O 6 00 +-----+---f---+------::.i""""""""---+-----+-----1 .0 c . 8 8 5 .00 +-----+-_,,_---+-----t---"'....,....-+-----+-----l ...., G> G> en 4 .00 +----~----+-----t-----"'""'"-:-----+-----1 g> a; 3.00 +---.,._-+----=,,,.,C--+--=""'"-""=1----+----"-.....:--+-----1 ~ 0.. 2.00 +-------:,_--:Y""-----+-----+---=--....:1::----.3!ji,,.,-----l o l.OO+--:~~=---+-----+-----t----t---=,,,__...i.-::---=:-....::---1 0 .00 ~;;._--+_;_---+---~.._ __ ...._ ___ .._.....:::::;;;;:~ 0 5 10 15 20 25 Time (Minutes) Pre -Dev elopment Hydrograph ---Post-Development Outflow Hydrograph Without Detention 30 Detention Pond Deoth Vs. Volume w Elevation Depth Volume (Feet) (Ft3) 293 .60 0 .00 0 293 .90 0 .30 80 294.10 0 .50 261 294 .60 1.00 1,127 295 .00 1.40 2,084 295 .75 2.15 4 ,217 Detention Pond Depth Vs. Volume 1.50 ~ $ ~ ...... ~ G> 0 1.00 O ~ 1~ 1~2~2~3W3~4W4~ Detention Pond Volume (Cubic Feet) Rat i ng Cyrve For Outlet ControLStructure We ir Len gth(L): 0.40 (4 .75") Depth.Vs. Volume Elevati o n Depth Disc ha rge (Feet) Ft3/Sec 293 .6 0 0.00 0.00 293.90 0 .30 0 .20 294 .10 0.50 0.42 294 .6 0 1.00 1.1 9 295 .0 0 1.40 1.97 295.7 5 2.15 3 .74 Rating Curve For Outlet Control Structure Depth Vs . V olume l 1.50 ~ ......,, J::. -a. G> a 1.00 0 .00 0 .50 1.00 1.50 2 .00 2 .50 3.00 3.50 4.00 Disc harge (Cubic Feet Per Second) ______________________ ___.. I Storage Indication Curve 4.00 ,, 3.50 c 0 ~ 3.00 t. 2.50 i 0 2.00 :0 ::;, ~ 1.50 Cl> ~ 0 1.00 s::. ~ 0 0.50 0.00 I' Depth (Feet) 0 .00 0 .30 0 .50 1.00 1.40 2.15 / ~ / Storage Discharge 2s/t 2s/t+O (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0 0 .00 0.00 0.00 80 0 .20 2.67 2.86 261 0 .42 8.70 9.12 1,127 1.19 37 .57 38 .75 2 ,084 1.97 69.47 71.43 4 ,217 3.74 140.57 144.31 Storage Indication Curve _.,, "" ~ v ~ v ~ v / v / 0.00 20.00 40 .00 60.00 80.00 100.00 120.00 140 .00 160.00 2s/t+O (Cubic Feet Per Second) Inflow I Outflow Simulation 2-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.60 0.00 1 0.42 0.42 0.36 0.42 0.03 0.08 293.68 0.86 2 0.83 1.25 1.39 1.61 0.11 0.20 293.80 1.36 3 1.25 2.08 3.03 3.47 0.22 0.32 293.92 1.70 4 1.66 2.91 5.33 5.94 0.31 0.40 294.00 1.91 5 2.08 3.74 8.23 9.07 0.42 0.50 294.10 2.12 6 2.49 4.57 11.78 12.81 0.52 0.57 294.17 2.27 7 2.91 5.40 15.92 17.18 0.63 0.65 294.25 2.43 8 3.33 6.24 20.64 22.16 0.76 0.74 294.34 2.58 9 3.74 7.07 25.91 27.71 0.90 0.83 294.43 2.74 10 4.16 7.90 31.69 33.80 1.06 0.93 294.53 2.89 11 3.95 8.11 37.37 39.79 1.21 1.01 294.61 3.02 12 3.74 7.69 42.38 45.06 1.34 1.08 294.68 3.12 13 3.53 7.27 46.76 49.66 1.45 1.14 294.74 3.20 14 3.33 6.86 50.53 53.62 1.54 1.19 294.79 3.27 15 3.12 6.44 53.73 56.98 1.62 1.23 294.83 3.33 16 2.91 6.03 56.38 59.76 1.69 1.26 294.86 3.37 17 2.70 5.61 58.51 61.99 1.74 1.29 294.89 3.41 18 2.49 5.20 60.14 63.71 1.78 1.31 294.91 3.44 19 2.29 4.78 61.30 64.92 1.81 1.33 294.93 3.45 20 2.08 4.36 62.00 65.66 1.83 1.33 294.93 3.46 21 1.87 3.95 62.28 65.95 1.84 1.34 294.94 3.47 22 1.66 3.53 62.15 65.81 1.83 1.34 294.94 3.47 23 1.45 3.12 61.62 65.26 1.82 1.33 294.93 3.46 24 1.25 2.70 60.73 64.33 1.80 1.32 294.92 3.44 25 1.04 2.29 59.48 63.02 1.77 1.30 294.90 3.42 26 0.83 1.87 57.90 61.36 1.73 1.28 294.88 3.40 27 0.62 1.45 56.00 59.36 1.68 1.26 294.86 3.37 28 0.42 1.04 53.79 57.04 1.62 1.23 294.83 3.33 29 0.21 0.62 51.29 54.41 1.56 1.20 294.80 3.29 30 0.00 0.21 48.52 51.50 1.49 1.16 294.76 3.24 -------- 4.50 4.00 3.50 -"O c 0 ~ 3.00 Cl) .. Q) 0.. 1 2.50 L&. 0 :0 2.00 j (.) ....... ~ 1.50 0 =§ 0 1.00 0.50 0.00 0 Inflow/Outflow Simulation 2-Year Storm Event I I I I I I I I Pre- Developme nt Hydrograph I I 5 - I I I - I I I I I -· -- I ' I I -· 10 ' ' .. ·-·-·- ' ' ' ' ' ' --·---·--------- 15 20 25 30 Time (Minutes ) Post-Post--• -• -• Post- Developme Developme Developme nt Outflow nt O utflow nt "Free- Hydrogroph With Fl ow' Without Det ention Detention Inflow I Outflow Simulation 5-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.60 0.00 1 0.51 0.51 0.44 0.51 0.03 0.09 293.69 0.92 2 1.01 1.52 1.69 1.95 0.13 0.23 293.83 1.45 3 1.52 2.53 3.73 4.21 0.24 0.35 293.95 1.77 4 2.02 3.54 6.56 7.26 0.35 0.45 294.05 2.00 5 2.53 4.55 10.16 11.11 0.47 0.54 294.14 2.20 6 3.03 5.56 14.54 15.72 0.59 0.63 294.23 2.38 7 3.54 6.57 19.65 21.11 0.73 0.72 294.32 2.55 8 4.04 7.58 25.46 27.23 0.89 0.82 294.42 2.72 9 4.55 8.59 31.92 34.05 1.07 0.93 294.53 2.89 10 5.05 9.60 39.01 41.52 1.25 1.04 294.64 3.05 11 4.80 9.86 46.01 48.87 1.43 1.13 294.73 3.19 12 4.55 9.35 52.19 55.36 1.58 1.21 294.81 3.30 13 4.30 8.85 57.60 61.04 1.72 1.28 294.88 3.39 14 4.04 8.34 62.27 65.94 1.84 1.34 294.94 3.47 15 3.79 7.83 66.23 70.10 1.94 1.38 294.98 3.53 16 3.54 7.33 69.52 73.56 2.02 1.42 295.02 3.58 17 3.29 6.82 72.17 76.35 2.09 1.46 295.06 3.62 18 3.03 6.32 74.21 78.49 2.14 1.48 295.08 3.65 19 2.78 5.81 75.67 80.03 2.18 1.50 295.10 3.67 20 2.53 5.31 76.58 80.98 2.20 1.51 295.11 3.68 21 2.27 4.80 76.96 81.38 ~ 1.51 295.11 3.69 22 2.02 4.30 76.85 81.26 1.51 295.11 3.69 23 1.77 3.79 76.25 80.64 2.19 1.50 295.10 3.68 24 1.52 3.29 75.21 79.54 2.16 1.49 295.09 3.66 25 1.26 2.78 73.74 77.99 2.13 1.47 295.07 3.64 26 1.01 2.27 71.85 76.01 2.08 1.45 295.05 3.62 27 0.76 1.77 69.58 73.62 2.02 1.43 295.03 3.58 28 0.51 1.26 66.94 70.84 1.95 1.39 294.99 3.54 29 0.25 0.76 63.94 67.70 1.88 1.36 294.96 3.50 30 0.00 0.25 60.60 64.19 1.79 1.32 294.92 3.44 6.00 5 .00 ,... "C c 0 0 4 .00 G> Cl) .. G> Q. l 3.00 u.. 0 :0 :J 0 ...... ~ 0 2.00 =§ 0 l.00 0 .00 0 In flow /Outflow Si mulat ion 5-Yea r Storm Even t I I I I • I I I I I 5 Pre-- Developme nt Hydrograph I I I I I I I I I I ..... ..... ..... ..... ..... ········ ·----··---- 10 15 ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ............... ···------- 20 25 Ti me (Minute s) ---Post-Post --------- Devel opme Developme nt Outflow nt Outfl ow Hydrograph With Without Detention Detention ..... 30 Post- Developme nt "Free- Flow" Inflow I Outflow Simulation 10-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation Velocity {Minutes) {Ft3/Sec) {Ft3/Sec) {Feet) {FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 293.60 0.00 1 0.57 0.57 0.49 0.57 0.04 0.10 293.70 0.96 2 1.13 1.70 1.89 2.19 0.15 0.25 293.85 1.50 3 1.70 2.84 4.21 4.73 0.26 0.37 293.97 1.81 4 2.27 3.97 7.40 8.18 0.39 0.47 294.07 2.06 5 2.84 5.11 11.49 12.51 0.51 0.57 294.17 2.26 6 3.40 6.24 16.45 17.74 0.64 0.66 294.26 2.45 7 3.97 7.38 22.22 23.82 0.80 0.77 294.37 2.63 8 4.54 8.51 28.77 30.73 0.98 0.88 294.48 2.81 9 5.11 9.64 36.06 38.42 1.18 1.00 294.60 2.99 10 5.67 10.78 44.08 46.84 1.38 1.11 294.71 3.15 11 5.39 11.06 51.98 55.14 1.58 1.21 294.81 3.30 12 5.11 10.50 58.97 62.48 1.75 1.30 294.90 3.42 13 4.82 9.93 65.09 68.90 1.91 1.37 294.97 3.51 14 4.54 9.36 70.37 74.45 2.04 1.43 295.03 3.59 15 4.25 8.79 74.85 79.16 2.16 1.49 295.09 3.66 16 3.97 8.23 78.57 83.08 2.25 1.53 295.13 3.71 17 3.69 7.66 81.58 86.23 2.33 1.57 295.17 3.75 18 3.40 7.09 83.89 88.67 2.39 1.59 295.19 3.79 19 3.12 6.52 85.56 90.42 2.43 1.61 295.21 3.81 20 2.84 5.96 86.60 91.51 2.46 1.62 295.22 3.82 21 2.55 5.39 87.05 91.99 © 1.63 295.23 3.83 22 2.27 4.82 86.95 91.88 1.63 295.23 3.83 4 23 1.99 4.25 86.30 91.20 2.45 1.62 295.22 3.82 24 1.70 3.69 85.15 89.99 2.42 1.61 295.21 3.80 25 1.42 3.12 83.52 88.27 2.38 1.59 295.19 3.78 26 1.13 2.55 81.42 86.07 2.32 1.56 295.16 3.75 27 0.85 1.99 78.89 83.41 2.26 1.54 295.14 3.72 28 0.57 1.42 75.94 80.31 2.18 1.50 295.10 3.68 29 0.28 0.85 72.60 76.79 2.10 1.46 295.06 3.63 30 0.00 0.28 68.88 72.88 2.00 1.42 295.02 3.57 Inflow/Outflow Simulation 10-Year Storm Event 7.00 6.00 I ' I ' • ' ' I ' 5.00 I ........ I ' "O c: I ' 0 I ~ ' I (I) I ' ... ' G> 4.00 ' A. -; I ' G> • " LI. I ' () " :0 I ' ::I 3.00 (.) ' ....., 3; I " 0 I ' = I ::I ' 0 I • 2.00 • I ' I I ' ' I l.00 I ' ' ' .. . . . ... ...... -.. ........ .. .... -... . . . . ..... .. .......... .. -.. 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-. . . . Post -Post -. ....... Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt 'Free- Hydrograph Hydrograph With Flow' Without Detention Detention Inflow I Outflow Simulation 25-Yea r Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0 .00 0 .00 0 .00 0 .00 0.00 0.00 293 .60 0 .00 1 0 .65 0 .65 0 .56 0 .65 0 .04 0.11 293 .71 1.00 2 1.30 1.94 2 .1 6 2.50 0 .17 0 .27 293 .87 1.57 3 1.94 3 .24 4.83 5.40 0 .29 0 .39 293.99 1.87 4 2 .59 4 .54 8.51 9 .36 0.43 0.51 294.11 2.13 5 3 .24 5.83 13.23 14 .34 0 .56 0 .60 294 .20 2.33 6 3 .89 7.13 18 .94 20 .36 0 .71 0 .71 294.31 2.53 7 4 .54 8.42 25.58 27.36 0 .89 0 .83 294.43 2.73 8 5.18 9.72 33.10 35 .30 1.10 0.95 294.55 2 .92 9 5 .83 11 .0 1 41 .48 44 .11 1.32 1.07 294.67 3 .10 10 6.48 12 .31 50 .70 53 .79 1.55 1.19 294.79 3 .28 11 6.16 12 .63 59.79 63 .34 1.77 1.31 294.91 3.43 12 5.83 11 .99 67 .82 71 .78 1.98 1.40 295 .00 3 .55 13 5.5 1 11 .34 74 .85 79 .16 2 .16 1.49 295 .09 3.66 14 5.18 10.69 80 .92 85 .54 2.31 1.56 295.16 3.75 15 4 .86 10.04 86 .08 90 .96 2.44 1.62 295 .22 3.82 16 4 .54 9 .39 90 .37 95.47 2.55 1.67 295 .27 3 .87 17 4 .21 8.75 93 .83 99 .11 2 .64 1.70 295.30 3.92 18 3 .89 8.10 96 .51 101 .93 2.71 1.73 295 .33 3.95 19 3 .56 7.45 98.44 103.96 2.76 1.75 295.35 3.97 20 3 .24 6.80 99 .66 105.24 2 79 1.77 295.37 3 .99 21 2.92 6.16 100.20 105 .82 (fib 1.77 295.37 4 .00 22 2 .59 5 .51 100.11 105.71 2.80 1.77 295.37 3.99 23 2 .27 4.86 99.40 104.97 2.78 1.76 295.36 3.99 24 1.94 4 .21 98 .11 103.61 2.75 1.75 295.35 3.97 25 1.62 3 .56 96.26 101.67 2.70 1.73 295.33 3 .95 26 1.30 2.92 93 .89 99 .18 2.64 1.70 295 .30 3.92 27 0.97 2.27 91.02 96.16 2.57 1.67 295.27 3 .88 28 0.65 1.62 87.67 92.64 2.48 1.64 295.24 3 .84 29 0 .32 0 .97 83 .87 88 .64 2.39 1.59 295.19 3.79 30 0 .00 0.32 79.64 84.19 2.28 1.54 295 .14 3.73 Inflow/Outflow Simulation 25-Yeor Storm Event 7.00 I ' ' I ' I ' 6.00 I I .. I ' ' I ' I ' 5.00 ' --I 'O ' c I ' 0 ~ I ' I ' ... I ' G> 4.00 CL I l .. I ' ~ 0 ' :0 I ' :J 3.00 ~ ~ • ' I 0 ' =§ I ' 0 I ' 2.00 ' ' I ' I I ' I " ' I ' 1.00 I ' ' ' . . . ............ .. .. -.. . . . .. ...... . . . .. .......... .. .... .. .. .... .. ... 0.00 . ........... 0 5 10 15 20 25 30 nme (Minutes) Pre -----Post-Post-...... -.. Post- Developme Develo pme Developme Developme nt nt Outflow nt Outflow nt 'Free- Hydrograph Hydrograph Wit h Flow· Without De t entio n Detention Inflow I Outflow Simulation 50-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0 .00 0 .00 0 .00 0 .00 0.00 293.60 0.00 1 0.73 0 .73 0.63 0.73 0 .05 0 .12 293.72 1.04 2 1.46 2.20 2.44 2 .83 0.19 0.30 293.90 1.64 3 2 .20 3 .66 5.48 6.11 0 .31 0.41 294.01 1.92 4 2 .93 5 .13 9.69 10.61 0.46 0 .53 294 .13 2.18 5 3.66 6.59 15.07 16 .28 0 .61 0.64 294.24 2.40 6 4.39 8.06 21.57 23.13 0 .78 0.76 294 .36 2.61 7 5.13 9 .52 29 .11 31 .09 0 .99 0 .89 294.49 2.82 8 5 .86 10.99 37 .66 40 .10 1.22 1.02 294.62 3 .03 9 6.59 12.45 47.19 50 .11 1.46 1.15 294 .75 3.21 10 7 .32 13.92 57.67 61.11 1.72 1.28 294 .88 3.39 11 6.96 14.28 67 .99 71 .95 1.98 1.41 295 .01 3.56 12 6.59 13 .55 77 .11 81 .54 2 .21 1.51 295.11 3.69 13 6.23 12.82 85.09 89.93 2.42 1.61 295.21 3.80 14 5.86 12.09 91 .99 97.18 2.59 1.68 295.28 3 .89 15 5.49 11.35 97.85 103.34 2 .74 1.75 295 .35 3 .97 16 5.13 10.62 102.73 108.47 2 .87 1.80 295.40 4 .03 17 4 .76 9 .89 106.68 112.62 2.97 1.84 295.44 4.07 18 4.39 9 .16 109.74 115.83 3 .05 1.88 295 .48 4 .11 19 4.03 8.42 111.95 118.16 3 .11 1.90 295.50 4 .13 20 3 .66 7 .69 113.35 119.64 3 .14 1.91 295 .51 4.15 21 3.30 6.96 113.99 120.31 GlD 1.92 295.52 4.16 22 2.93 6.23 113.91 120.22 1.92 295 .52 4.16 6 23 2.56 5.49 113.13 119.40 3.14 1.91 295 .51 4.15 24 2 .20 4 .76 111.69 117.89 3 .10 1.90 295.50 4.13 25 1.83 4 .03 109 .62 115.72 3.05 1.87 295.47 4.11 26 1.46 3.30 106.96 112.92 2 .98 1.85 295.45 4 .08 27 1.10 2.56 103.73 109 .53 2.90 1.81 295.41 4 .04 28 0.73 1.83 99 .97 105.57 2.80 1.77 295 .37 3.99 29 0 .37 1.10 95.69 101.07 2.69 1.72 295.32 3.94 30 0.00 0 .37 90 .92 96 .05 2.57 1.67 295.27 3 .88 8 .00 7.00 6.00 -"O c 0 0 5 .00 G> Cl) ... G> Q. i 4 .00 ..... 0 :0 ::::J (.) -~ 3 .00 =§ 0 2 .00 1.00 0.00 0 Inflow/Outflow Simulation 50-Year Storm Event I • Pre- • • • • • • • • I • Developme nt Hydrograph 5 • I • • . . . -- I • . ' . ' . ' I I • • I ' ' ' ... . . .. .. -............ - 10 ' ' ' ' ' .. ......... . 15 ' ' ' ' " ' -.............. .. 20 25 ' Time (Minutes ) --Post -Post-.............. De velopme Developme nt Outflow nt Outflow Hydrograph With Withou t Detention Detention ' ' Post - 30 Developm e nt "Free- Flow " Inflow I Outflow Simulation 100-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0 .00 0.00 0 .00 0.00 0.00 0 .00 293 .60 0 .00 1 0.76 0 .76 0 .66 0 .76 0.05 0 .12 293.72 1.06 2 1.53 2 .29 2.56 2.95 0.20 0 .30 293 .90 1.65 3 2.29 3 .82 5.74 6.38 0.32 0.42 294 .02 1.94 4 3.06 5.35 10.15 11.09 0.47 0 .54 294.14 2.20 5 3 .82 6.88 15.78 17.03 0.62 0.65 294.25 2.42 6 4.59 8.41 22 .57 24.19 0.81 0 .78 294.38 2.64 7 5.35 9.94 30.46 32.52 1.03 0.91 294.51 2 .86 8 6.12 11.47 39.4 1 41.93 1.26 1.04 294.64 3 .06 9 6.88 13 .00 49 .38 52.41 1.51 1.18 294.78 3.25 10 7 .65 14.53 60.34 63.91 1.79 1.31 294.91 3.44 11 7 .26 14 .91 71 .13 75 .25 2.06 1.44 295.04 3.60 12 6 .88 14 .15 80.67 85 .28 2.30 1.56 295.16 3.74 13 6.50 13 .38 89 .01 94 .05 2.52 1.65 295.25 3 .85 14 6.12 12.62 96 .22 101 .63 2.70 1.73 295.33 3 .95 15 5.74 11 .85 102 .36 108.08 2.86 1.80 295.40 4 .02 16 5.35 11 .09 107.46 113.45 2.99 1.85 295.45 4 .08 17 4 .97 10 .32 111 .59 117.79 3.10 1.89 295.49 4 .13 18 4 .59 9 .56 114.79 121 .15 3 .18 1.93 295 .53 4 .17 19 4.21 8.79 117.11 123.59 3.24 1.95 295.55 4.19 20 3 .82 8.03 118.59 125.14 3 .28 1.97 295 .57 4 .21 21 3.44 7 .26 119.27 125.85 GlD 1.97 295.57 4 .22 22 3.06 6.50 119.18 125.77 1.97 295.57 4.21 9 23 2.68 5.74 118.38 124.92 3.27 1.96 295.56 4.21 24 2 .29 4.97 116.88 123.35 3.23 1.95 295 .55 4 .19 25 1.91 4 .21 114.73 121.09 3 .18 1.93 295.53 4.16 26 1.53 3.44 111.96 118.17 3 .11 1.90 295.50 4.13 27 1.15 2.68 108.60 114.64 3.02 1.86 295.46 4.10 28 0 .76 1.91 104 .67 110.51 2 .92 1.82 295.42 4 .05 29 0 .38 1.15 100.2 1 105 .82 2.81 1.77 295.37 4.00 30 0.00 0 .38 95.23 100 .59 2.68 1.72 295.32 3 .93 Inflow/Outflow Simulation 100-Year Storm Event 9.00 8.00 ' I -. I ' I .. 7.00 ' .. I ' I I ' ...... 'O 6.00 I c: ' 0 I ~ I ~ ' Cl) I ... ... Q) I ' Q. 5.00 -I ... $ I ' "" I ' 0 ' :0 I ;, 4.00 ' () I ' ...... ~ I ' 0 I ~ I ' 3.00 ' 0 I ' I I I 2.00 I I I ' ' 1.00 ' ' ' -. -. .......... .. ... . . . . . . .. ...... .. --...... 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post-....... -Post - Developme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph With Flow· Without Detention Detention ...... "C c 0 1.40 ~ 1.20 ~ Q. l LL. 1.00 0 :0 :;, g ~ 0.80 0 ~ 0 0 .60 0 .40 0 .20 0.00 0 Inflow/Outflow Simulation 2-Year Storm Event 5 10 15 20 25 30 Time (Minutes ) ---Pre -Development Hydrograph ---Tot a l Post -Development Hydrogra ph Inflow/Outflow Simulation 5 -Year Storm Even t 2.50 2.00 ...... ,, c: 0 0 G> 1.50 Cl) ... G> Q. * u.. 0 :0 :;, 0 -~ 1.00 0 ~ 0 0.50 0.00 0 5 10 15 20 25 30 Tim e (Minutes) Pre-Development Hydrograph ----Total Post-Development Hydrograph Inflow/Outflow Simulation 10-Year Storm Event 0 5 10 15 20 25 30 Time (Minutes) ---Pr e-Development Hydrogra ph ----To tal Post -Development Hy drograph .- CITY OF COLLEGE STATION Post Office Box 9960 1101 Texas Avenue College Station, Texas 77842-0960 November 1, 1994 Garrett Engineering 4444 Carter Creek Blvd., Suite 108 Bryan, TX 77802 Attn : Earl Havel RE: KFO Mini Storage Facility Drainage Report Dear Earl , (409) 764-3500 I have completed my review of the drainage plan and report for this project, and am returning it with comments for correction . In particular, we have a policy of not allowing detention for private facilities within the public right of way. I know that an exception was made for your Pershing Park project, but this site is different with the possibility of sidewalk and ADA ramps being installed in the future . It is my understanding that to place the detention basin as shown on your plans, that a maintenance agreement would have to be reached with the City, which would include a variance to the use of the right of way for your basin . Once you have looked these comments over, it may help to arrange a meeting with myself, Mark Smith and Kent Laza if you still wish to pursue this design . z:;I' . Brett M!fl:- Project Manager cc: Kent Laza, City Engineer Veronica Morgan, Assistant City Engineer Shirley Volk, Development Coordinator Home of Texas A&M University Inflow /Outflow Simula tion 25-Year Storm Event 3.50 3.00 2.50 ....... 'O c: 0 ~ Cl) ... 2.00 G> ~ -* ..... 0 :a ;:, 0 1.50 ...., ~ 0 ~ 0 1.00 0.50 0.00 0 5 10 15 20 25 30 Time (Min ut e s) ---Pre -Development Hydrograph ---Total Post-Development Hydrograph Inflow/Outflow Simulation 50-Year Storm Event 3.00 ...... 'O c 0 0 ~ 2.50 .... G> 0.. -m 2.00 u.. 0 :0 ~ 0 "" ~ 1.50 0 =§ 0 1.00 0 5 10 15 20 25 30 nme (Minutes) Pre-Development Hydr ograph ---Total Post-De ve lopment Hyd rograph Inflow/Outflow Simulation 100-Year Storm Event ...... "O c 0 4 .00 3.00 ~ 2.50 Gi a.. i IA. 2 .00 0 :0 :J ~ ~ 1.50 0 =§ 0 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Post-Development Hydrograph Printed by Veronica Morgan From: Shirley Volk CONFIRMED To: Jim Smith, Joey Dunn, Jon Mies, Sabina Kuenzel, Steve Homeyer, Tony Michalsky, Veronica Morgan Subject: Kahan Self Storage ===NOTE===============9/06/95==2:24pm== This is the mini -storage warehouse on Manual Drive. Mr. Kahan has called in for his final building inspection for tomorrow sometime, so if that passes, he will want his c.o. Please schedule your inspection and forward the results to me asap. Thanks. 9/06/95 Y.RA.V'-- f{I ,, v--- C?I<. ~ •"'-t, /Z;46'?,m. "1~1 /?S- ~ Page: 1 3:07pm ....... \I