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Home My WebLink About65 Development Permit 518 Bug Blasters ExpansionFigure XIl Development Permit City of College Station, Texas Site Legal Description: /.or;, /loCJt tJ~ Site Owner: !JoBE/ L/i£ Architect/ Engineer : ~7-~4~ Contractor : Date Application Filed : ________ _ TI. llD"»1TZetJ Address : !711 J ~ $/Diss t!5. "'lR. 77Y~ Telephone : IR93 · 3(p5/ Address : #ii ~ t2eR~ l?:;f>J, 7Jt. ?71!oz Telephone No : ~'~2(,(8' Address: ~------------Telephone No : _________ _ Approved : __________ ~ Application is hereby made for the following development specific waterway alterations : D Application Fee Signed Certifications D Drainage and erosion control plan, with supporting Drainage Report two (2) copies each . D Site and Construction Plans, with supporting Drainage Report two (2) copies each . D Other: ACKNOWLEDGMENTS : I, lb11d!t/ 6~reff , design engineer, hereby acknowledge or affirm that: The information and conclusions contained in the above plans and supportin g 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. Property Owner(s) Contractor ..... .. , " . ·. ' \, .. Figure XII Continued CERTIFICATIONS : (for proposed alterations within designated flood hazard areas .) A I , certify that any nonresidential structure on or proposed to be on this site as part of this application is designated.to prevent damage to the structure or its contents as a result of flooding from the 100 year storm. Engineer Date B . I, certify that the finished floor elevation of the lowest floor, including any basement, of any residential structure, proposed as part of this application is at or above the base flood elevation established in the latest Federal Insurance Administration Flood Hazard Study and maps , as amended. Engineer Date C . _)<}, Dnetd H2vve,,1/--, certify that the alterations or development covered by t~s per~t shal~ not dimi ~j~ h¥.!fl'~~~~trrying capacity of the wate:way ad~oining ?r crossing this p~rrrutted site and ~~t .:~u.c~er-~h~ or developmen~ are consistent with requirements of the City of College St~'t10.rt C1t w>de , ~~ter 13 concerning encroachments of flood ways and of fl c.· : :•~ 00 way innges . r ·oaNA.Lo .. 6AR:R.Err .... ~ z ................................... f z : .:ct:~ <)/t~~ • . :-v; ••• .s st ......... ~-;.~".: l\ ... ONAL. ~---.,,,,,,,,,,..,. 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 D ate Conditions or cornrnents 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 . DRAINAGE COMPUTATIONS For Lot 1, Block One T.J. Addition College Station, Brazos County, Texas Prepared By: Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 *May, 1994 * DRAINAGE COMPUTATIONS For Proposed Parking Lot Improvements To Be Located Lot 1, Block One T.J. Addition College Station, Brazos County, Texas *M ay, 1994 * SUMMARY The proj ect consists of th e construction of parkin g lot improve ments establishing 5 additional 9 foot x 18 foot s paces. The intention of th e data presented here in is to determine th e increase in s to nn water run-off subseq uent to th e proposed improvrnents to th e s ite. On-site detention facilities may not be req uired based on conversations wiU1 city e ngi neerin g s taff (B . Mcully & David Pull e n) as a possible detention facility may be in s tall ed off-site in assoc iation wiU1 U1 e Sebesta Road Rehabilitation Project which could facilitate th e minute in crease in run-o ff ge ne rated by th e subj ect proj ect. From the computation s on page 1 based on th e proj ect area of 0.07 acres as shown on the aforementioned Site & Grading Plan, th e pred evelopm e nt run-off coefficient being assumed at 0.40 and a minimum time of concentration of 10 minutes the re lative predevelopme nt peak di sc harge rates ("Q") were determined . The intensities shown on pa ge 1 were take n from "Figure IIl-1 Intensity Duration Frequency Curves For The City Of College Station"as contained in U1 e "Drainage Policy and Design Standards for the City of College Station" ass uming sam e minimum time of concentration of 10 minutes. The Rational M e thod was utilized to compute U1e estimated peak predevelopment di sc harge rates. The equation that re prese nts the Rational Method is as follows: Q = CIA, where; "Q" is th e peak discharge rate in cubic feet per second. "C" is th e run-off coefficient, in th e predevelopment condition "C" is assumed to be 0.40, "I" is th e storm inten s ity in in che p er hour and "A" which is th e area of th e s ite in acres . From U1e computations on page 2 based on U1 e proj ec t area of 0.07 acres, th e postdevelopm e nt run-off coefficient being assumed at 0.98 and a minimum tim e of concentration of 10 minutes th e relative predevelopment peak discharge rates ("Q") were determined. The inten sities s hown on page 1 were taken from "Figure III-I Tnt ens ity Duration Frequency Curves For The City Of College Station"as contained in U1 e "Drainage Policy and Design Standards for th e City of College Station" assuming same minimum time of concentration of 10 minutes. The Rational Me thod was utilized to com pute U1 e es timated peak post development discharge rates. The equation that repre sents th e R a tional Method is as follows: Q = CIA, where; "Q" is the peak discharge rate in cubic feet per second . "C" is th e run-off coefficient, in th e post development condition "C" is assumed to be 0.98, "I" is th e storm inte nsity in inches per hour and "A" which is th e area of U1e site in acres. The comparison between peak predevelopm ent discharge rates and post development discharge rates is include d as an aid to U1 e designer to es tabli sh a preliminary "target" as to the volume necessary in Ule proposed de tention facility should a detention facility be deem ed necessary. This pre liminary estimate is arrived at by sim ply dete nninin g U1 e volume generated from Ule differe nce of the predevelopme nt and post development hydrographs (see pages 5-7 for predevelopme nt and post developme nt hydrographs). Please note that U1e post developm e nt hydrograph shown on th ese sam e graphs assumes no detention. Page 3 and page 4 are tabulations of U1 e predevelopme nt hydrograph and th e post development hydrograph based on th e computations pe rform ed on page 1 and page 2. The post development hydrogra ph ass um es no detention to facilitate direct comparison in th e pre ' and pos t developm ent conditions. The hydrograph s are trian g ular in sha pe and are based on th e standard SCS unit hydro gra ph with tim e to peak se t equal to th e tim e of concentration a nd th e total time base se t a t 2.67 tim es th e tim e of concentration. Please note th at a 26.7 minute total stonn event duration was utili zed ex clu siv ely throu g hout thi s report du e totally to th e small physical s ize of tJ1e proj ect. Determine Total Pre-Development Peak Storm Water Discharge Rates Tributary Ar ea ("A"): 0.07 Acres Pervious A rea: 0.07 Acres Impervious Ar ea : 0.00 Acres Run-Off Co efficient ("Cwt"): 0.40 T ime Of Co ncentration ("T/c "): Woodland s: Low Elevation: High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vw"): Time : Pa st ure s: Low Elevation : High Elevat ion : Distance (Feet): S lope (% Grade): Velocity ("Vp "): Time : Pavements : Low Elevation : High Elevation : Distance (Feet): Slope (% Grade): Velocity ("Vpave"): Time : Total Travel Time : Hourly In te nsity Rates ("I"): 2-Year: 5.20 5-Year: 7.69 10-Yea r: 8.63 25-Y ear : 9.86 50-Y ea r: 11 .15 100-Year: 12.60 Peak Discharge Rate ("O"): 2-Year: 0.15 5-Yea r: 0.22 10-Year: 0 .24 25-Year: 0.28 50-Year: 0.31 100-Year: 0.35 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 Inc hes I Hour Inches I Hour Cubic Feet I Second Cub ic Feet I Seco nd Cub ic Feet I Second Cub ic Feet I Seco nd C ubi c Feet I Seco nd Cubic Feet I Seco nd De t ermine Post-development Peak Storm Water Dischar e No Detention T ribu tary A rea ("A "): 0.07 Acres Pervious Area : 0.0 0 Acres Impervious Area : 0.07 Acres Run-Off Coefficient ("Cwt"): 0.98 Time Of Co ncentration ("T/c "): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year : 5.20 5-Year : 7.7 0 10 -Year : 8.60 25 -Year : 9.90 50-Yea r: 11 .2 0 100-Year: 12.60 c = 0.40 C= 0.98 Inches I Hou r Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Peak Discharge Rate ("O "): 2-Year: 0.36 Cubic Feet I Second 5-Yea r: 0.53 Cubic Feet I Secon d 10-Year: 0.59 Cubic Feet I Second 25-Year : 0.68 Cubic Feet I Seco nd 50-Year : 0.77 Cubic Feet I Seco nd 100-Year: 0.86 Cubic Feet I Second Comparison Of Predevelopment And Post-develo ment Peak Dischar e Rates Predeve lopment Pos t -Developme nt Inc rease 2-Yea r: 0.15 Ft3 /sec 0.36 Ft3 /sec 0.21 Ft3 /sec 5-Year : 0.22 Ft3 /sec 0.53 Ft3 /sec 0.3 1 Ft3/sec 10-Year: 0.24 Ft3 /sec 0.59 Ft3 /sec 0.35 Ft3 /sec 25-Year: 0.28 Ft3 /sec 0.68 Ft3/sec 0.4 0 Ft3/sec 50-Year: 0.31 Ft3 /sec 0.77 Ft3 /sec 0.46 Ft3/sec 100-Year: 0.35 Ft3/sec 0.86 Ft3 /se c 0.51 Ft3/sec Prel iminary Determination Of Detention Pond Volume 2-Year: 0.21 Ft3 /sec x (26.7 Min . x 60 Se c . I 2 ) = 169 Cubic 5-Year: 0.31 Ft3 /sec x (26.7 Min . x 60 Sec . I 2 ) = 251 Cubic 10-Year: 0.35 Ft3 /sec x (26 .7 Min . x 60 Sec . I 2 ) = 279 Cubic 25-Yea r: 0.4 0 Ft3 /sec x (26 .7 Min . x 60 Sec . I 2 ) = 323 Cubic 50 -Yea r: 0.46 Ft3 /sec x (26 .7 Min . x 60 Sec . I 2 ) = 365 Cubic 100-Year: 0.51 Ft3 /sec x (26 .7 Min . x 60 Sec . I 2 ) = 410 Cub ic Feet Feet Feet Feet Feet Feet Pre-Development 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 0.01 0.02 0.02 0.03 0.03 0.04 2 0.03 0.04 0.05 0.06 0.06 0.07 3 0.04 0.06 0.07 0.08 0.09 0.11 4 0.06 0.09 0.10 0.11 0.12 0.14 5 0.07 0.11 0.12 0.14 0.16 0.18 6 0.09 0.13 0.15 0.17 0.19 0.21 7 0.10 0.15 0.17 0.19 0.22 0.25 8 0.12 0.17 0.19 0.22 0.25 0.28 9 0.13 0.19 0.22 0.25 0.28 0.32 [ ---" -~ ._..... ___ ... -Peak=> 10 0.15 0.22 Q.2.i__ 0.2§ _ _0.}1 0.35 -N ----11 0.14 0.20 0.23 0.26 0.29 0.33 12 0.13 0.19 0.21 0.24 0.27 0.31 13 0.12 0.18 0.20 0.23 0.26 0.29 14 0.11 0.16 0.18 0.21 0.24 0.27 15 0.10 0.15 0.17 0.19 0.22 0.25 16 0.09 0.14 0.15 0.18 0.20 0.23 17 0.08 0.13 0.14 0.16 0.18 0.20 18 0.08 0.11 0.13 0.14 0.16 0.18 19 0.07 0.10 0.11 0.13 0.14 0.16 20 0.06 0.09 0.10 0.11 0.13 0.14 21 0.05 0.07 0.08 0.09 0.11 0.12 22 0.04 0.06 0.07 0.08 0.09 0.10 23 0.03 0.05 0.05 0.06 0.07 0.08 24 0.02 0.03 0.04 0.04 0.05 0.06 25 0.01 0.02 0.02 0.03 0.03 0.04 26 0.01 0.01 0.01 0.01 0.01 0.01 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 Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.04 0.05 0.06 0.07 0.08 0.09 2 0.07 0.11 0.12 0.14 0.15 0.17 3 0.11 0.16 0.18 0.20 0.23 0.26 4 0.14 0.21 0.24 0.27 0.31 0.35 5 0.18 0.26 0.29 0.34 0.38 0.43 6 0.21 0.32 0.35 0.41 0.46 0.52 7 0.25 0.37 0.41 0.48 0.54 0.61 8 0.29 0.42 0.47 0.54 0.61 0.69 9 0.32 0.48 0.53 0.61 0.69 0.78 r -------... -Peak=> 10 0.36 0.53 0.59 0.68 0.77 0.86 -. . --11 0.34 0.50 0.55 0.64 0.72 0.81 12 0.31 0.46 0.52 0.60 0.68 0.76 13 0.29 0.43 0.48 0.56 0.63 0.71 14 0.27 0.40 0.45 0.52 0.58 0.66 15 0.25 0.37 0.41 0.48 0.54 0.61 16 0.23 0.34 0.38 0.44 0.49 0.55 17 0.21 0.31 0.34 0.39 0.45 0.50 18 0.19 0.28 0.31 0.35 0.40 0.45 19 0.16 0.24 0.27 0.31 0.35 0.40 20 0.14 0.21 0.24 0.27 0.31 0.35 21 0.12 0.18 0.20 0.23 0.26 0.30 22 0.10 0.15 0.17 0.19 0.22 0.24 23 0.08 0.12 0.13 0.15 0.17 0.19 24 0.06 0.09 0.10 0.11 0.12 0.14 25 0.04 0.05 0.06 0.07 0.08 0.09 26 0.01 0.02 0.02 0.03 0.03 0.04 27 0.00 0.00 0.00 0.00 0.00 0.00 )" ..... Cl> Q.. -Cl> Cl> a; Q.. Qi Cl> ~ Total Pre -Development Hydrograph Vs . Total Post - Development Hydrograph For 2 -Year Storm Event 0 .35 ------+-----l"w-----+------+-----+--------i 0 .30 -----+---------If---------+-----+-----+------< .2 B 0 .25 ...-------t--_,__----1r-----~-------t-----t------i .0 c: 8 8 0 .2 0 ------+;------1r-------t-------t-----+-------i ....., Cl> ~ (j) 0 .15 1----~~-------:::J<::-----t-----""it-----t------i 0 .t::. 0 II) 0 0 . 10 1"---F---t----,..,.c;.._---+----=-t-.::::----t-----"'o..------t-------1 0 .05 +-_,_-----::.,.,.C--+-----11------t------t=,,,._=--~-+------1 0 .00 ~---..... -----1~---+----...... ----~ .... --.... 0 5 10 15 20 25 3( Time (Minutes) ---Pre-Development Hydrograph ----Total Post-Development Hydrograph 0 .60 0 .50 Total Pre -Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event ~,.... 0 .40 ·-'U .0 c: 8 8 0 .30 ....., Cl> Cl> (j) 0 .20 Ol ..... 0 .t::. 0 .10 0 II) 0 0 .00 0 5 Pre-Development Hydrograph 10 15 20 25 30 Ti me (M inutes) ----Po st-D evelopment Outfl ow Hydrograph Wi t hout Detention 0 .60 .... Cl> a.. 0 .50 -Cl> Cl> ~,..... 0.40 ·-'O ..0 c 8 8 0 .30 ..._, Cl> Cl> (/) 0 .20 0) .... 0 s::. 0 .10 0 U) 0 0 .00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 ---Pre-Development Hydrograph ----Post-Development Outflow Hydrograph With out Detention 0 .70 .... Cl> a.. -0 .60 Cl> Cl> 0 .50 LL. 0,..... ·-'O ..0 c 0 .40 :J 0 u 0 0 .30 ..._, Cl> Cl> (/) 0) 0 .20 .... 0 s::. 0 0 .10 U) 0 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 Pre-Development Hydrograph ----Post-Development Outflow Hydrograph Without Detention ') 0.80 -Q) 0 .70 0.. -Q) 0 .60 Q) ..... . 2 B o .50 .0 c 8 8 0 .40 ...., Q) Q) Cl) 0 .30 O'> -0 .20 0 .&; 0 0 .10 "' 0 0.00 0.90 -Q) 0 .80 0.. -Q) 0 .70 Q) ~ ...... 0 .60 ·-'O .g c 0.50 u 0 0 .40 ...., 0 Q) ~ O'> 0 .30 -0 0 .20 .&; 0 "' 0 .10 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-D evelopm e nt Outfl ow Hydrogra p h With out Detention 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 -Developm e nt Outflow Hydrograph With out Detention