Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
18 Drainage Computation Brazos County Farm Bureau 00-38
[P'~ . • ~oR RE.\J\ \Ne E. C0 A . \_\~1 c I ti\~'< -~ !000 c:GE. s1Ana coLLt;.;. C! G ENG\NI;. DRAINAGE COMPUTATIONS· For Brazos--Coun-ty Fa1m a-ureau 31lQQ .StataHighway.3Q College Station, Brazos County, Texas Prepared for Brazos .. County .. Earm .. Bureau P.O . Box 435 Bryan , Texas 77806-04_35 Telephone: (409) 778-6000 Prepared by: Garrett.Engineering_ 4444 Carter Creek Parkway -Suite 108 Bryan , Texas 77802 _ Telephone : (409) 846-2688 * April, 2000 * Garrett En!jneering -«44 Carter Creek Parl<way Suite 108 -Bryan, TeX>S 77802-Telephone: (409) 840-2688 -Fax: (409) 846-3094 -Page 1 DRAINAGE COMPUTATIONS for Brazos County Farm Bureau College Station, Brazos County, Texas * April , 2000 * SUMMARY The subject project is situated on the south side of State Highway 30 Approximately 2000 feet southwest of the intersection of F .M 158 and State Highway 30 in College Station, Brazos Comity, Texas (See Exhibit "A" -Project Location & Vicinity Map). The property consists of a total of 2.00 acres of land which is currently undeveloped. The total drainage basin tributary to the development is 0.94 acres ofland (See Exhibit "C" - Site Plan). A storm water detention facility is proposed to be constructed at the rear of the proposed development which will incorporate a 2' wide concrete pilot channel which slopes at a 0 .50 % grade to the low end of the detention pond where an ten inch (10") diameter p .v .c . storm sewer line "meters" the stonn water discharge at a rate less than the predevelo{)ment discharge rate from the subject property . Said 10" diameter p .v .c . pipe rwis 18' at 0 .50% to match existing growid The detention pond is designed to facilitate up to and include the ultimate 100-year storm event, and discharge at a rate less than the current pre-development peak discharge rates . The proposed detention facility will intercept and meter rwi-off from 0 .94 acres of the subject site . A benn is to be constructed along the southwest property line to the detention facility as well as to the north of the facility . The berm will help direct storm water rwi-off to the detention facility while not allowing any "free-flow" to rwi off the tributary area. Computations presented on page 2 present the estimated pre-development peak discharge rates generated by the 2, 5 , 10 , 25 , 50 and 100-year storm events. The weighted pre-development rwi-off coefficient was assumed to be 0 .30 based on a total tributary drainage basin area of0.94 acres of which is currently undeveloped (C = 0 .30). A 10-minute time of concentration (Tic) was estimated utilizing topographic maps and field reconnaissance. The Rational Metllod was employed exclusively throughout this document to compute the estimated peak storm water discharge rates . The equation that represents the Rational Metllod is as follows : Q = CIA, where ; "Q" is the peak discharge rate in cubic feet per second, "C" is tl1e rwi-off coefficient, assumed to be 0.30 in the pre-development condition, "I" is tlle storm intensity in inches per hour, and "A" is tlle area of the tributary drainage basin in acres . A 30-minute total stonn event duration was utilized exclusively throughout this report . From t11e computations on page 3 , based on the total tributary area of 0 .94 acres, the post-development weighted run-off coefficient being assumed at 0.57, and a minimun1 time of concentration of 10 minutes , the relative post-development peak discharge rates ("Q") were detennined and presented in tabular form . The Rational Method was again utilized to compute tlle estimated peak post-development discharge rates . Computations depicted on page 3 assume no detention . Pages 7 -10 depict pre-development and post- development hydrographs for the 2, 5, 10 , 25 , 50 and 100-year storm events with no detention considered. A comparison between the peak pre-development discharge rates and post-development discharge rates is included to aid in establishing a preliminary "target" for the volume requirements for the proposed detention facility . This preliminary estimate is computed by detennining the volume generated from the Page 1-1 difference of the pre-development and post-development hydrographs. Please note that the post- development hydrograph shown on these same graphs assumes no detention at this point in the computational process. Page 3 provides computations that determine the post-development storm water run-off which is allowed to flow from the subject site unmetered and page 6 provides computations that determine the post- development run-off that is routed through the proposed detention facility . The "free-flow" run-off computations presented on page 5 are based on a time of concentration of 10 minutes (minimum), the run- off routed through the proposed detention facility as presented on page 6 is calculated based on a time of concentration of 10 minutes . Pages 7-8 and pages 9-10 are tabulations of the pre-development hydrographs and the post-development hydrographs respectively, based on the computations perfom1ed on pages 2 & 3. The post-development hydrograph assumes no detention to facilitate direct comparison in the pre-and post-development conditions . Pages 11-12 and pages 13-14 are tabulations of the post- development hydrograph for "free-flow" storm water run-off and storm water run-off directed through the detention facility respectively . Having derived the preliminary volume requirements as presented on page 3 and "allowable peak" discharge rate as present on page 2 it is now possible to design the final detention facility and outlet control structure. Page 20 presents a tabulation and depth versus volume graph of the detention facility as proposed. The maximum pond volume necessary to provide sufficient storage for the 100-year storm condition was estimated to be approximately 2703 cubic feet (page 3) .. The actual design for the proposed detention pond supplies 4011 cubic feet at a water surface elevation of 282 .63' (Top Of Berm). The actual design volume of 4011 cubic feet allows for an approximate. 0 .5' between the elevation at the 100-year storm and the top ofberm (page 44), as required by the city. Page 22 presents a tabulation and rating curve for the proposed outlet control structure. A 10" diameter p .v .c . pipe outlet control structure was chosen due to depth verses discharge ratio characteristics associated with the anticipated headwater depth and convenience of construction. Page 23 presents a tabulation of the relationship between discharge from the detention and the dimensionless quantity 2S/t-O. Also included is the Storage Indication Curve for the proposed detention facility based on the aforementioned physical characteristics of the detention pond, storage volume, inflow hydrographs, and rating curve for the outlet structure. The storage indication curve as shown on page 23 is a graphical solution to the equation presented as follows : 2s 1 (11+12) + (--------------01) dt 2s2 (-----------------+ 02) dt Pages 24-45 , present simulations for the 2. 5, 10, 25, 50 and 100-year storm events. The first and second pages of each storm frequency simulation represents the tabulated data for tl1e storm event. The third page of each storm simulation represents the pre-development hydrograph. the post-development hydrograph (witl1 no detention), the post-development hydrograph as routed through the detention pond and the post-development "free-flow" hydrograph for each storm event. Pages 47-53 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 for the 2 and 5 year storm event are within 0 .1 cfs of predevelopment peak discharge rates for the respective storm event. And the 10 . 25 , 50 and 100 year storm events have been reduced from those peak pre-development discharge rates due to the incorporation of the proposed detention facility . Therefore, the construction of the proposed detention facility will minimize the effects of development on downstream property owners and will actually decrease the peak discharge rates for the range of storm events of interest within this report. Page 55 is a graph that summates the depths, volumes. and percent of "utilized" storage volumes for the 2, 5, 10 , 25 , 50 and 100-year storm events . Page 1-2 PRO ECT LOCATION N VICINITY MAP -not to scale - Exhibit "A" Determine Total Pre-Development Peak Sto'rm Water Discharge Rates Tributary Area ("A"): 0.94 Acres Pervious Area : 0.94 Acres Impervious Area : 0.00 Acres Run-Off Coefficient ("Cwt"): 0.30 Time Of Concentration ("T/c"): Woodlands: Low Elevation : High Elevation : Distance (Feet): Slope (% Grade): Velocity ("Vw"): Tima ~ 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 Trffilel T ime : Hourly Intensity Rates ("I"): 2-Year: 6 .33 S-Year: 7.69 10-Year: 8.63 2S-Year: 9.86 SO-Year: 11.1S 100-Year: 11.64 Peak Discharge Rate ("Q"): 2-Year: 1.78 S-Year: 2.17 10-Year: 2 .43 2S-Year: 2 .78 SO-Year : 3.14 100-Year: 3.28 c = 0.30 c = 0.90 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 Garrett E1'9neering-4444 Carter Creek Par1cway Suite 108 -Bryan , Texas 77802 -Telephone : (409) 846-2688 -Fax: (409) 846-3094 -Page 2 Determine Post-development Peak Storm Water Discharge· (No Detention) Tributary Area ("A"): 0.94 Acres Pervious Area: lrnpe.rvious Area : 0.51 Acres 0.43 Acres . Run-Off Coefficient ("Cwt"): 0.57 Time Of Concentration C'T/c"): 1 O Minutes Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Yeai:: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11.15 1-00 -Year: 1-1,64 c = 0.30 c = 0.90 Inches I Hour lnclles /Hour Inches I Hour Inches I Hour Inches I Hour ~nches.I Hour ·-. Peak Discharge Rate ("Q"): 2-Year: 3.42 Cubic Feet I Second 5-Year: 4.15 Cubic Feet I Second 10-Year: 4.66 Cubic Feet I Second 25-Yeaf; ~33 Cubic F-eet I Second 50-Year: 6.02 Cubic Feet I Second·- 100-Year: 6 .29 Cubic Feet I Second Comparison Of Predevelopment And P-ost.;.ctevetopment Peak Di·sctfarge Rates Predevelopment 2-Year: 1 . 78 ft3/sec 5-Year: 2.17 Ft3/sec 1Q...Year: 2.43 Ft3.lsec . 25-Year: 2. 78 Ft3/sec 50-Year: 3 .14 Ft3Lsec 100-Year: 3.28 Ft3/sec Prelimin-al)f-Determination-Of . Detention Pond Volume 2-Year: 1.63 Ft3/sec x (30 Min . 5-Year: 1 . 98 Ft3/sec x (30 Min. 10-Year: 2.23 Ft3/sec x (30 Min . 25-Year: 2.54 Ft3/sec x (30 Min. 50-Year: 2.88 Ft3/sec x (30 Min. 100-Year: 3.00 Ft3/sec x (30 Min. Post-D.eveJopme_nt 3.42 Ft3/s.ec 4.15 Ft3/sec 4 ,66. Ftl/sec 5.33 Ft3/sec 6.02.. Ft3/sec 6 .29 Ft3/sec x 60 Sec . I 2 ) = x 60 Sec. I 2 ). = x 60 Sec. I 2 ) = x 60 Sec. I 2 ) = x 60 Sec. I 2 ) = x 60 Sec. I 2 ) = Increase 1.63 ft3/sec 1.98 Ft3/sec 2.23 Ft3/sec 2.54 Ft3/sec 2.88 Ft3/sec 3.00 Ft3/sec 1,469 Cubic Feet 1,786 Cubic Feet 2 ,005 Cubic Feet 2,290 Cubic Feet 2 ,588 Cubic Feet 2 ,703 Cubic Feet ~ternline-P~st-Devetopment '-'F-ree-Fk>-w!! Peak Storm Water Discharge. Tributary Area ("A"): 0.00 Acres Pervious Area : Q_QO _ Acres_ Impervious Area : 0.00 Acres Run-Off Coefficient ("Cwt"): 0.00 G_= 0.30 c = 0.90 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 5.Cb Year:. 11.1.5_ lnches I Hour 100-Year: 11 .64 Inches I Hour Peak Discharge Rate ("Q"): 2-Year: 0.00 Cubic Feet I Second 5-Year: 0.00 Cubic Feet I Second 10-Year:_ OJlQ Cubic...feei/Second 25-Year: 0.00 Cubic Feet I Second 50-Year: 0.00 Cubic Feet I Second 100-Year: 0 .00 Cubic Feet I Second Garrett Engi neering · 4444 Carter Creek Parl<way Suite 108 • Sry!lfl, Tens 77802 -TeieP>one : (409) 846-2588 -Fax: (409) 846-3094 -Page 4 ·Determine-Post-Development .. · Flow Into Detention Pond Tributary Area ("A"): 0.94 Acres Pervious Area: 0.51 Acres Impervious Area : 0.43 Acres Run-Off Caefficieat ("Cwt")_:. 0 _57 Time Of Concentration ("T/c"): 10 Minutes Hourly Intensity Rates ("I").: 2-Year: 6 .33 5-Year: 7.69 iO~Yea E 8.63 25-Year: 9.86 SO-Year: 11.15 100-Year: 11 .64 Peak Discharge Rate ("Q"): 2='lear 3.-42. 5-Year: 4 .15 10-Year: 4 .66 25-Year: 5 .33 50-Y.eai:: 6 .0.2 100-Year: 6.29 c = 0.30 c = 0 .90 Inches I Hour Inches I Hour lnches .t.-~ur Inches I Hour Inches I Hour Inches I Hour Cubic.Feet/ Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second <Amie Feet I Second Cubic Feet I Second ' Garrett Engneering-4444 Carter Creek ParXwa.y Suite 108-Bryan, Tens 77802 -Telephone: (409) 846-2688 -Fax: (409) 846-3094 -Page 5 Pre-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year SO-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 o.oo ()..()().. 0.00 0.00 0.00-1 0.18 0.22 0.24 0.28 0.31 0.33 2 0.36 0.43 0.49 0.56 0.63 0.66 3 0.54 0.65 0.73 0.83 0.94 0.98 4-0.71-0..87 0..91 1.11 1.26 1.3~ 5 0.89 1.08 1.22 1.39 1.57 1.64 6 1.07 1.30 1.46 1.67 1.89 1.97 7 1.25 1.52 1.70 1.95 2.20 2.30 8 1.43-· 'L74--1.95 2-.22 2.51 2.63 9 1.61 1.95 2.19 2.50 2.83 2.95 ta_ 1.z.a __ ;= =c.2....11, 2-43-2..18 .. ccc .... • 3.14 3.28 11 1.69 2.06 2.31 2.64 2.99 3.12 12 1-.6-1 1-.95 2.1-9 2.SQ ... 2.83 2.95 13 1.52 1.84 2.07 2.36 2.67 2.79 14 1.43 1.74 1.95 2.22 2.51 2.63 15 1.34 1.63 1.83 2.09 2.36 2.46 16-1.25-1-.52 1.70.-1-.95-2.20 2.30 17 1.16 1.41 1.58 1.81 2.04 2.13 18 1.07 1.30 1.46 1.67 1.89 1.97 19 0.98 1.19 1.34 1.53 1.73 1.81 20. 0..89-1-.08--1..22 1.39-1.57 1.64 21 0.80 0.98 1.10 1.25 1.41 1.48 22 0.71 0.87 0.97 1.11 1.26 1.31 23 0.62 0.76 0.85 0.97 1.10 1.15 24-0.54-0..65-0.-73 0..83 0.94 0.98 25 0.45 0.54 0.61 0.70 0.79 0.82 26 0.36 0.43 0.49 0.56 0.63 0.66 27 0.27 0.33 0.37 0.42 0.47 0.49 28 0.1-S. 0..22 0..24-0..28---0.31 0.33 29 0.09 0.11 0.12 0.14 0.16 0.16 30 0.00 0.00 0.00 0.00 0.00 0.00 31 0.00 0.00 0.00 0.00 0.00 0.00 32 0.00-0..-00. 0.00.. o.oo 0.00 0.00 33 0.00 0.00 0.00 0.00 0.00 0.00 34 0.00 0.00 0.00 0.00 0.00 0.00 35 0.00 0.00 0.00 0.00 0.00 0.00 36 o.oo .. 0.00 0.00-0,00 0.00 0,09 37 0.00 0.00 0.00 0.00 0.00 0.00 38 0.00 0.00 0.00 0.00 0.00 0.00 39 0.00 0.00 0.00 0.00 0.00 0.00 40 0.00-0.00 0..00. o..oo. 0.00 0.00 41 0.00 0.00 0.00 0.00 0.00 0.00 42 0.00 0.00 0.00 0.00 0.00 0.00 43 0.00 0.00 0.00 0.00 0.00 0.00 44-0.00.. 0.00-0.00-0.00. 0.00 0.00 45 0.00 0.00 0.00 0.00 0.00 0.00 Garrett Engineering-44•4 Carter Creek Pat1<way Suite 108 -Bryan, Texas 77802 -Te~: (409) 846-2688 -Fax: (409) 84tr3094 -Page 6 46 0.00 0.00 0.00 0.00 0.00 0.00 47 0.00 0.00 0.00 0.00 0.00 0.00 48 0.00 0.00 0.00 0.00 0.00 0.00 49 0.00 0.00 0.00 0.00 0.00 0.00 50 0.00 0.00 0.00 0.00 0.00 0.00 51 0.00 0.00 0.00 0.00 0.00 0.00 52 0.00 0.00 0.00 0.00 0.00 0.00 53 0.00 0.00 0.00 0.00 0.00 0.00 54 0.00 0.00 0.00 0.00 0.00 0.00 55 0.00 0.00 0.00 0.00 0.00 0.00 56 0.00 0.00 0.00 0.00 0.00 0.00 57 0.00 0.00 0.00 0.00 0.00 0.00 58 0.00 0.00 O.OQ 0.00 0.00 0.00 59 0.00 0.00 0.00 0.00 0.00 0.00 60 0.00 0.00 0.00 0.00 0.00 0.00 Garrett Engneering • 4444 Carte< Creek Paricway Suite 108-Bryan, Texas 77802-Tele!i><>ne: (409) 846-2688 -Fax: (409) 846-3094 -Page 7 Post-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) 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 0.34 0.42 0.47 0.53 0.60 0.63 2 0.68 0_8-3. 0.93. 1.07 1.20 1.26 3 1.02 1.25 1.40 1.60 1.81 1.89 4 1.37 1.66 1.87 2.13 2.41 2.51 5 1.71 2.08 2.33 2.66 3.01 3.14 6 2.05 2.A.9 2-.80. 320. 3.61 3.77 7 2.39 2.91 3.26 3.73 4.21 4.40 8 2.73 3.32 3.73 4.26 4.82 5.03 9 3.07 3.74 4.20 4.79 5.42 5.66 1Q .. 3.42 .. . .4..1.5.. ''-"-;;. 4-6.6-. 5..33.. 6.02 6.29__ 11 3.25 3.95 4.43 5.06 5.72 5.97 12 3.07 3.74 4.20 4.79 5.42 5.66 13 2.90 3.53 3.96 4.53 5.12 5.34 14 2.73 3..32. 3.73. 4.26. 4.82 5.03 15 2.56 3.12 3.50 3.99 4.51 4.71 16 2.39 2.91 3.26 3.73 4.21 4.40 17 2.22 2.70 3.03 3.46 3.91 4.09 18 2.05 2....49. 2..8Q 3..20. 3.61 3.77 19 1.88 2.28 2.56 2.93 3.31 3.46 20 1.71 2.08 2.33 2.66 3.01 3.14 21 1.54 1.87 2.10 2.40 2.71 2.83 22 1.37 1.66 1.87 2...13_ 2.41 2.51 23 1.20 1.45 1.63 1.86 2.11 2.20 24 1.02 1.25 1.40 1.60 1.81 1.89 25 0.85 1.04 1.17 1.33 1.50 1.57 26 0.68 0..8.3. OJU 1.0.7 -1.20 1.26 27 0.51 0.62 0.70 0.80 0.90 0.94 28 0.34 0.42 0.47 0.53 0.60 0.63 29 0.17 0.21 0.23 0.27 0.30 0.31 30 O.OQ a.a.a o_o.a_ 0.00 0.00 0.00 31 0.00 0.00 0.00 0.00 0.00 0.00 32 0.00 0.00 0.00 0.00 0.00 0.00 33 0.00 0.00 0.00 0.00 0.00 0.00 34 0.00 o_oo. O.QQ Q.00 0.00 0.00 35 0.00 0.00 0.00 0.00 0.00 0.00 36 0.00 0.00 0.00 0.00 0.00 0.00 37 0.00 0.00 0.00 0.00 0.00 0.00 38 O.OQ 0.0..Q Q_QQ_ 0.00 0.00 0.00 39 0.00 0.00 0.00 0.00 0.00 0.00 40 0.00 0.00 0.00 0.00 0.00 0.00 41 0.00 0.00 0.00 0.00 0.00 0.00 42 0.00 0.00 O~O.Q 0.00 0.00 0.00 43 0.00 0.00 0.00 0.00 0.00 0.00 44 0.00 0.00 0.00 0.00 0.00 0.00 45 0.00 0.00 0.00 0.00 0.00 0.00 Garrett Engineering-4444 Carter Creek Pancway &ite 108 -Bryon, Texas n802 -Telephone; (409) 846-2688 -Fax (409) 846-3094 -Page 8 46-o.oo. o,.QO.. 0 . .00-0.00 . 0.00 o.oo 47 0.00 0.00 0.00 0.00 0.00 0.00 48 0.00 0.00 0.00 0.00 0.00 0.00 49 0.00 0.00 0.00 0.00 0.00 0.00 50 0.00. o.oo. 0,QQ. o,oo -0.00 O.QQ 51 0.00 0.00 0.00 0.00 0.00 0.00 52 0.00 0.00 0.00 0.00 0.00 0.00 53 0.00 0.00 0.00 0.00 0.00 0.00 54--0.00-ChQO. 0.00-0-.00 0.00 O..QO 55 0.00 0.00 0.00 0.00 0.00 0.00 56 0.00 0.00 0.00 0.00 0.00 0.00 57 0.00 0.00 0.00 0.00 0.00 0.00 58 0.00-0,00-0.00 0.-00-0.00 0..00 59 0.00 0.00 0.00 0.00 0.00 0.00 60 0.00 0.00 0.00 0.00 0.00 0.00 Garrett Ef9neering-4444 Corter Creek Por1<woy Suite 108 • Bryan, Texas 77802 • Tetepllone: (409) 84&-2688 -Fox: (409) 846-3094 -Page 9 Post-Development "Free-Flow" Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year SO-Year 100-Year (Minutes) Storm Storm Sto[m Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.00 0.00 0.00 0.00 0.00 0.00 2 0.00-o.oo. o.oo. o.oo 0.00 0.00 3 0.00 0.00 0.00 0.00 0.00 0.00 4 0.00 0.00 0.00 0.00 0.00 0.00 5 0.00 0.00 0.00 0.00 0.00 0.00 6-0.00-o.oo. <hOO o.oo. 0.00 0.00 7 0.00 0.00 0.00 0.00 0.00 0.00 8 0.00 0.00 Q.00 0.00 0.00 0.00 9 0.00 0.00 0.00 0.00 0.00 0.00 10 0.00 0.00--0.00 0.00-0.00 O..QQ 11 0.00 0.00 0.00 0.00 0.00 0.00 12 0.00 0.00 0.00 0.00 0.00 0.00 13 0.00 0.00 0.00 0.00 0.00 0.00 14-0.00-0-.00-0.00 0-.00.. 0.00 0.00 15 0.00 0.00 0.00 0.00 0.00 0.00 16 0.00 O.OQ 0.00 0.00 0.00 0.00 17 0.00 0.00 0.00 0.00 0.00 0.00 18 0.00-0.00-0 . .00--o.oo.. 0.00 0~00 19 0.00 0.00 0.00 0.00 0.00 0.00 ' 20 0.00 0.00 0.00 0.0.0 0.00 0.00 21 0.00 0.00 0.00 0.00 0.00 0.00 22 0.00.. 0.00 0.00.. 0.00-. 0.00 0.00 23 0.00 0.00 0.00 0.00 0.00 0.00 24 0.00 0.00 0.00 0.00 0.00 0.00 25 0.00 0.00 0.00 0.00 0.00 0.00 26-o.oo... 0.00-0-.00.. 0.00--0.00 0.00 27 0.00 0.00 0.00 0.00 0.00 0.00 28 0.00 0.00 0.00 0.00 0.00 0.00 29 0.00 0.00 0.00 0.00 0.00 0.00 30--0.00-o .. oo 0.00-0..00-0.00 0.00 31 0.00 0.00 0.00 0.00 0.00 0.00 32 0.00 0.00 0.0_0 0.00 0.00 0.00 33 0.00 0.00 0.00 0.00 0.00 0.00 34-0.00-0.00 0.00 0.00 0.00 0.00 35 0.00 0.00 0.00 0.00 0.00 0.00 36 0.00 0.00 O.OQ 0.00 0.00 0.00 37 0.00 0.00 0.00 0.00 0.00 0.00 38-0.00-o .. oo .. 0 . .00 0.00 0.00 0.00 39 0.00 0.00 0.00 0.00 0.00 0.00 40 0.00 0.00 0.00 0.00 0.00 0.00 41 0.00 0.00 0.00 0.00 0.00 0.00 42-0.00-<hOO--0 • .00 0.00 0.00 0.00 43 0.00 0.00 0.00 0.00 0.00 0.00 44 0.00. 0.00 O.OQ 0.00 0.00 0.00 45 0.00 0.00 0.00 0.00 0.00 0.00 Garrett Ellgjneering.-4444-Carter-Cl"eel<P-y--Suil<> 108-Bryan, T.,..._ H802· TelepAolle:.(o400}846-268a -~--{409)-846-3094--~-11). 46 0.00 0.00 0.00 0.00 0.00 0.00 47 0.00 0.00 0.00 0.00 0.00 0.00 48 0.00 Q_OD. Q__QO 0.00 0.00 0.00 49 0.00 0.00 0.00 0.00 0.00 0.00 50 0.00 0.00 0.00 0.00 0.00 0.00 51 0.00 0.00 0.00 0.00 0.00 0.00 52 0.00 0.00 0.0.0. CLOO 0.00 0.00 53 0.00 0.00 0.00 0.00 0.00 0.00 54 0.00 0.00 0.00 0.00 0.00 0.00 55 0.00 0.00 0.00 0.00 0.00 0.00 56 0.00 a.no CLOO. o_oo 0.00 O.QQ 57 0.00 0.00 0.00 0.00 0.00 0.00 58 0.00 0.00 0.00 0.00 0.00 0.00 59 0.00 0.00 0.00 0.00 0.00 0.00 60 0.00 O..QQ O_QQ o_oo 0.00 0.00 Garrett Engineering-4444 Carter Creel< Parl<way Suite 108 -Bryan, Texas 77802 ·Tel~: (409) 846-2688 • Fax: (409) 846-3094 -Page 11 Post-Development Flow Routed Through Detention Pond Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year SO-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 o_oo. o...o_o 0.00 0.00 0.00 1 0.34 0.42 0.47 0.53 0.60 0.63 2 0.68 0.83 0.93 1.07 1.20 1.26 3 1.02 1.25 1.40 1.60 1.81 1.89 4 1.37 1 .. 66. 1.8.7 2_13 2.41 2.51 5 1.71 2.08 2.33 2.66 3.01 3.14 6 2.05 2.49 2.80 3.20 3.61 3.77 7 2.39 2.91 3.26 3.73 4.21 4.40 8 2.73 3 .. 32. 3J3 .. 4.26 4.82 5.03 9 3.07 3.74 4.20 4.79 5.42 5.66 10 3 .. 42 . .4.15 4~66 5.33" 6.02 6.29 11 3.25 3.95 4.43 5.06 5.72 5.97 12 3.07 3-74 4.W 4.79 5.42 5.66 13 2.90 3.53 3.96 4.53 5.12 5.34 14 2.73 3.32 3.73 4.26 4.82 5.03 15 2.56 3.12 3.50 3.99 4.51 4.71 16 2.39. 2Jl1. 326. 3.73 .. 4.21 4.40 17 2.22 2.70 3.03 3.46 3.91 4.09 18 2.05 2.49 2.80 3.20 3.61 3.77 19 1.88 2.28 2.56 2.93 3.31 3.46 20. 1.71 2...08. 2 . .33. 2...66. 3.01 3.14 21 1.54 1.87 2.10 2.40 2.71 2.83 22 1.37 1.66 1.87 2.13 2.41 2.51 23 1.20 1.45 1.63 1.86 2.11 2.20 24.. 1.02.. 1.25. 1 .40. 1_60 1.81 1.89 25 0.85 1.04 1.17 1.33 1.50 1.57 26 0.68 0.83 0.93 1.07 1.20 1.26 27 0.51 0.62 0.70 0.80 0.90 0.94 28 0.3A 0.42. 0.47 0_53 0.60 0.63 29 0.17 0.21 0.23 0.27 0.30 0.31 30 0.00 0.00 0.00 0.00 0.00 0.00 31 0.00 0.00 0.00 0.00 0.00 0.00 32. O.OQ QOfr. 0..00_ 0_00 .. 0.00 0.00 33 0.00 0.00 0.00 0.00 0.00 0.00 34 0.00 0.00 0.00 0.00 0.00 0.00 35 0.00 0.00 0.00 0.00 0.00 0.00 36 0.00 0.00 0.00 0.00 0.00 0.00 37 0.00 0.00 0.00 0.00 0.00 0.00 38 0.00 0.00 0.00 0.00 0.00 0.00 39 0.00 0.00 0.00 0.00 0.00 0.00 40 0.00 Q_Q_O QO.O. 0.00 0.00 0.00 Gi!lrrett Engineering-4444 Carter Creek Parkway Suite 108 -Bryan, Texas 77802-Telephone: (409) 846-2688 -Fax: (409) 846-3094 -Page 12 -41 0.00 0.00 0.00 0.00 0.00 0.00 42 0.00 0.00 0.00 0.00 0.00 0.00 43 O.OQ Q.OH Q_QO. 0.00 0.00 0.00 44 0.00 0.00 0.00 0.00 0.00 0.00 45 0.00 0.00 0.00 0.00 0.00 0.00 46 0.00 0.00 0.00 0.00 0.00 0.00 47 0.00 O.OQ_ 0.0.0. O.OD 0.00 0.00 48 0.00 0.00 0.00 0.00 0.00 0.00 49 0.00 0.00 0.00 0.00 0.00 0.00 50 0.00 0.00 0.00 0.00 0.00 0.00 51 0.00. 0.00 Q.00 0.00 0.00 0.00 52 0.00 0.00 0.00 0.00 0.00 0.00 53 0.00 0.00 0.00 0.00 0.00 0.00 54 0.00 0.00 0.00 0.00 0.00 0.00 55 0.00 0.0.0 O.QQ O.JlO 0.00 0.00 56 0.00 0.00 0.00 0.00 0.00 0.00 57 0.00 0.00 0.00 0.00 0.00 0.00 58 0.00 0.00 0.00 0.00 0.00 0.00 59. 0.00 0 . .00 0 . .0.0 0.0.0 0.00 0.00 60 0.00 0.00 0.00 0.00 0.00 0.00 Garrett Engineering-4444 Carter Creek Parkway SUite 108 -Bryan, Texas 77802 -Teles:none: (409) 846-2688 -Fax: (409) 846-3CHM -Page 13 4 .00 -'CJ. g 3.50 u ~ "' 3.00 ... Q) a; -2.50 Q) Q) ~ 2.00 .c ::I' 2. 1.50 ~ ~ 1.00 CIS .c:... ~ 0.50 Ci 0.00 :c-4 .50 c: fr-*:66 Q) "' 3.50 ... Q) a. 3 .00 -cir-if 2 .50 l.J_ :c z:oo- ::J 2. t .50. Q) ~ 1 .00 CIJ"" 'fi 0.50 Cl) o-o .oo Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharg_e Rates 2-Year Storm Event ~ ) \ I \ I \ I J ~ \~ I !l I '...," \ // ' ,\ "-, I .,, :// ',\ " 0 10 20 30 40 50 60 Time (Minutes) ·----·Pre-Development Hydrograph -Total Post-Development Hydrograph Total Pre-Development Vs. Total Post-Development (No Detentionl Peak Discharge Rates 5-Year Storm Event \. I '\ ~ I '\ I \ .. I '-\ I / "-.,,, \. /;I ""'· '\ f / "'·' fl -~ 0 10 20 3o_ 40 50 60 Time (Minutes) ·----Pre-Development Hydrograph -Post -Development Outflow Hydrograph Without Detention GarTett Engneering -4444 Carter Creek Parkway Suite 108 -Bryan , Texas 77802 -Telephone : (409) 846-2688 -Fax: (409) 846-3094 -Page 14 70 70 5 .00 --g-· 4~50' 0 ~4 .00. en cu 3 .50 a; Qi 3.00 Q) u. u 2 .50 :c :::J z:ocr ~ .. 1-.50- Cl ... ~.1 .00 u i5 0 .50 0 .00 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharg_e Rates 10-Year Storm Event ~ I \ I \ I \ I \ I J "-· 'f\ I / ~, \ // '\ '·, '\ ~11 ""\ r '\ 0 10 20 30 40 50 60 Time (Minutes) --P re ~Development Hydr.ograph . -PasbDellelopment Outflo.w .Hydrograph WithouLDetention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharg_e Rates 25-Year Storm Event 70 6.00 -----~--~---~---~--~---~--~ -'O c: 8 5 .00 ------#t------l----+------+------+----+-----~ Q) en ... £-4 :UU--+----l--+---.----+-----+------+----l-----+-----j -Q) Q) u. .~ 3 .00 .Q __ :::J ~ 2.00 _____ -----;,__+--->,.----+-----+------+------<----+-------I Q)· Cl ... !IS fr· t :Of)-.. -oc+--+---+-----+--"<----'--+----+------+-----+------l Cl) c 10 30--50 60-. 70 Time_(Minutes) -·--Pre-Development Hydrograph -Post-Development Outflow Hydrog raph Without Detention Garrett Engineering-4444 Carter Creek Parkway Suite 108 -Bryan, Texas 77802 • Telei:tione : (409) 846-2688 -Fax: (409) 846-3094 -Page 15 -'0- Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 50-Year Storm Event § 6 .00--------------1-----+-----+------+----+----~ C,) QI - (/) ~ 5 .00 a;. -~ 4 .00----+--+---------if------+-----+------+----+----~ u. C,) :g-3...00..-------,,o+->.,..._. __ __, ______ -+-----+------+----;-----~ 0 -!;• 2:00--~-_,_-+-----"<--+-___., __ __,_ ____ ,____ ___ _,_ ___ _,_ ___ ----i ... ns .r;__ ~ 1.00--.,.._,,.. __ _,_ ___ __, ____ ____,,,_-+-___ -+-___ --+----+----~ i5 0 .00+-------+-------+-------~~~~-+--~~~...-~~~+-----t 0 10 20 30 40 50 60 Time (Minutes) -·----Pre-Development Hydrograph. -PoshD.eitelapment Outflow Hydrograph W itho.ut Cletention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 100-Year Storm Event 70 :c-7 .oo-----~---~---~---~----~---~--~ c 0- ~ 6 .oo-----~----+-----+-----+----1-----+-----1 (/) ~ s .oo------+--+--"1£----+-----+-----+----1-----+-----1 -:-4 .00---------<I---+---~-+-----+------+----+-----+-------< LL u... ~ 3 .oo---#--f"-~r----~---+----+-----+------+-----1 :l 0 ;--2 .00------_,.--+--------+-----<,..._--+------+----+-----+------< Cl ... ~-1 .00 __,,.......... __ -+-----+-------+------+----+-----+------< C,) Ill 0 0 .00 ~------1....---..... ----r-............................................... -1 ........ ...-............. ----t 0 10 20 30-50 60 - Time (Minutes) --Pre-Development Hydrograph -Post-Development Outflow Hydrog raph Without Detention Garrett Engneering · 4444 Carter Creek Parkway Suite 108 ·Bryan , Texas 77802 ·Telephone: (409) 846-2688 -Fax: (409) 846-3094 -Page 15 Detentiot+Pond. De· th Vs. Volume -... cu cu ~ .c ... Q. cu c 1 .50 1":00·· Elevation 280 .59 280 .70 281 .00 281.50 282 .00 282.63 Depth (Feet) 0 .00 0.11 0 .41 0.91 1.41 2 .04 Volume (Ft3) 0 9 331 1,348 2 ,568 4 ,011 Detention Pond Depth Vs. Volume 0 ;00-+---+----+----+----+----+----+---+---+----t- o 500 1 ,000 1,500 2 ,000 2 ,500 3,000 3 ,500 4,000 4 ,5 00 Detention Pond Volume (Cubic Feet) Garrett Engjn...,;ng-4444 Carter Creek Parkway &;le 108 -Bryan, Texas 77802 -Telephone : (409) 84&2688 -Fax: (409) 846-309-I -Page 17 Rating Curve For Outlet Control Structure D · th--VS:-Votume Elevation Depth (Feet) 280 .59 0.00 280.70 0 _11 281.00 0.41 281 .50 0 .91 282 .00 1 .41 282 .63 2 .0.4 .. :e Discharge Ft3/Sec 0 .00 0 .03 0 .37 1 .50 2 .53 3 .33 Rating Curve For Outlet Control Structure Depth Vs. Volume 2.00--------+-----+-----+------+-------i----f---..,::;;'---j 1.50 -+-'-·-· Cl.I Cl.I LL -.t:. ... Q. C1L 0 1.00 0 .00 "'f----1----1----+----+----+----+-----I 0.00 0 .50 1 .00 1 .50 2 .00 2.50 3 .00 3 .50 Discharge (Cubic Feet Per Second) - I Storage-Indication Curve --I Depth Storage Discharge 2s/t 2s/t+O (Feet) (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0.00 0 0.00 0 .00 0.00 0.11 9 0 .03 0 .29 0 .32 0 .41 331 0.37 11 .04 11 .41 0 .9.t 1,3..4.8__ 1.SQ _ 4_4_92__ 46 .42 1.41 2 ,568 2 .53 85 .60 88 .13 2 .04 4 ,011 3 .33 133.69 137.02 Storage Indication Curve _ 2.50--~~--t~~~--+-~~--i~~~-1--1~~1--~~-+-~~~+--~~--1 "O c: 0 (.) ar -m ... :. 2 .aa---~~--+~~~-+-~~__.~,_~-+-~~~1--~~-+-~~~+--~~-1 ~ Q) Q)_ __ lL (.) .0-- ::::7 2.. 1.so--~~--+~~~--+--1--~--i~~~-+-~~~1--~~-+-~~~+--~~--1 Gr- Cl ... ns .c (.) (II o.-r.oo--~-~~~-t-~#----t~~~--+-~~---1r--~~-t-~~~1--~~-+-~~--1 0.00 .... ---..---.... ----.---..... --........... --.... ---.,_--....-- 0.00 20.00 40.00 60.00--80-.00 --1-00.00. 120.00 140.00-1-6Q_QO 2s/t+O (Cubic Feet Per Second) Garrett Engineering-4444 Carter Creek Par1<way Suite 108 -Bryan, Texas 77802-Telephone: (409) 84er2688 -Fax: (409) 84&.3094 -Page 19 -Inflow I Outflow Simulation 2-Year-Ston:n Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 0.00 0.00-0..00-0.00-0.00--0.00 2S0..5_9 1 0.34 0.34 0.28 0.34 0.03 0.11 280.70 2 0.68 1.02 1.18 1.31 0.06 0.14 280.73 3 1.02 1.71 2.68 2.89 0.11 0.18 280.77 4-1.37-2.39--4.-72-5.0-7 0-.1-8 0.24 280...&? 5 1.71 3.07 7.27 7.79 0.26 0.31 280.90 6 2.05 3.76 10.31 11.03 0.36 0.40 280.99 7 2.39 4.44 13.80 14.75 0.48 0.46 281.05 a... 2.73-5.12 17-.10-18.-9-2-0.6-1 0.52 28Lt1 9 3.07 5.81 21.99 23.51 0.76 0.58 281.17 10 3.42 6.49 26.64 28.48 0.92 0.65 281.24 11 3.25 6.66 31.14 33.30 1.08 0.72 281.31 1-2 3.07 6.32 35.04-3-1-.46-1-.21 0.78 281..3? 13 2.90 5.98 38.37 41.02 1.33 0.83 281.42 14 2.73 5.64 41.16 44.01 1.42 0.88 281.47 15 2.56 5.30 43.46 46.46 1.50 0.91 281.50 16-2.39 4.95 45,.31-48-.4-1--1-.55--0.93 281.52 17 2.22 4.61 46.75 49.92 1.59 0.95 281.54 18 2.05 4.27 47.79 51.02 1.61 0.97 281.56 19 1.88 3.93 48.46 51.72 1.63 0.97 281.56 2() 1.11 3.59--4S.11 52.05--1.64--0.98 281.5] 21 1.54 3.25 48.74 52.02 1.64 0.98 281.57 22 1.37 2.90 48.39 51.64 1.63 0.97 281.56 23 1.20 2.56 47.72 50.95 1.61 0.96 281.55 24---1.02 2.22-4&.-11-49.95-1.59 0.95 28-'.l-.5_4 25 0.85 1.88 45.54 48.65 1.56 0.94 281.53 26 0.68 1.54 44.05 47.08 1.52 0.92 281.51 27 0.51 1.20 42.32 45.24 1.46 0.89 281.48 28--0.34--0.85-4().,.38--~1-7 1.40--· 0.86 28-t.A.5 29 0.17 0.51 38.25 40.89 1.32 0.83 281.42 30 0.00 0.17 35.94 38.42 1.24 0.80 281.39 31 0.00 0.00 33.61 35.94 1.16 0.76 281.35 32 0.00 0.00--3-1-.44--33.6-1-1.09-0.73 281.32 33 0.00 0.00 29.41 31.44 1.02 0.70 281.29 34 0.00 0.00 27.51 29.41 0.95 0.67 281.26 35 0.00 0.00 25.73 27.51 0.89 0.64 281.23 36-0.00 0.00--2-4.-06--25-:7-3-0-.83-0.61 281.20 37 0.00 0.00 22.51 24.06 0.78 0.59 281.18 38 0.00 0.00 21.05 22.51 0.73 0.57 281.16 39 0.00 0.00 19.69 21.05 0.68 0.55 281.14 40--0.00-0.00-1-8.41-19,69-0..64---0.53 28-1.1.? 41 0.00 0.00 17.22 18.41 0.60 0.51 281.10 42 0.00 0.00 16.11 17.22 0.56 0.49 281.08 43 0.00 0.00 15.06 16.11 0.52 0.48 281.07 44--0.00-0.00-.. 14.09-1.S.06-0.49-. 0.46 281.0~ 45 0.00 0.00 13.18 14.09 0.46 0.45 281.04 Garrett Engineering-4444 Carter Creek Parkway Suite 108-Bryan, Texas nso2-Telephone: (409) 846-2688 -Fax: (409) 846-3094 -Page 20 -46 0.00 0.00 .. 12.32.._ 13...1a 0..43 0.44 28-1.03 47 0.00 0.00 11.52 12.32 0.40 0-42 281.01 48 0.00 0.00 10.78 11.52 0.37 0.41 281.00 49 0.00 0.00 10.08 10.78 0.35 0.39 280.98 50 Q_OO_ 0.00.. 9...42_ 10....08 0_3..3.. 0.37 28.0.96 51 0.00 0.00 8.80 9.42 0.31 0.36 280.95 52 0.00 0.00 8.22 8.80 0.29 0.34 280.93 53 0.00 0.00 7.68 8.22 0.27 0.32 280.91 54 Q.D.O_ 0.00_ ·z_1a 7 _68. Q2fL 0.31 28.Q.90 55 0.00 0.00 6.69 7.16 0.24 0.30 280.89 56 0.00 0.00 6.23 6.69 0.23 0.28 280.87 57 0.00 0.00 5.81 6.23 0.21 0.27 280.86 58 O_QQ 0.00. 5-42.._ 5..81 0.20 0.26 280.85 59 0.00 0.00 5.04 5.42 0.19 0.25 280.84 60 0.00 0.00 4.69 5.04 0.17 0.24 280.83 Garrett Engineering-4444 Carter Creek Par1cway &lite 108-Bryan, Texas 77802-Telepl!one: (409) 84&-2688 -Fax: (409) 84&-3094 -Page 21 - -,, c O-u Q) "' ... Q) D.. ----Q) Inflow/Outflow Simulation 2-Year Storm Event ' ' ' l ' ~ 2.00 --~~---~+-~~~-'--+-~~~~-t-~~~~-t-~~~~-t-~~~~+-~~~----; tr ' :c ::::J ~ ~ o . I I l ~ 1.50 --~~~~'-+~-----~~+-~~---~-+-~~~~--t~~~~~-+-~~~~--+-~~~~--t 0-I • I I ' I , I , t.o~---~~;.--~.j#.-~~~++~---'-'~~-+---'!.__~~+-~~~-+~~~~-+-~~~---i I / \ : I \ ',, 5 ) I \ o. o--_,_~......--+-~~~-+~-.-_.._--+~~~~t-----~~+-~~~-+-~~~~ \ \ \ ' \' ' o .oo.-.------+-------1------.....,..1--------t-------+-------+-------~ 0 10 20 30 40 50 Time (Minutes) ·-··--·-----Pre-Development Hydrograph - - -Post-Development Outflow Hydrograph Without Detention Post-Development Outflow With Detention --- -Post-Development "Free-Flow" 60 Garrett Engineering-4444 Carter Creek Par1<way Suite 108 -Bryan, Texas 77802 -Tele~e: (409) 846-2688 -Fax: (409) 846-3094 -Page 22 70 Inflow I Outflow Simulation 5-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 0.00 0.00 0.00 0.00 0.00 0.00 280.59 1 0.42 0.42 0.35 0.42 0.03 0.11 280.70 2 0.83 1.25 1.46 1.60 0.07 0.14 280.73 3 1.25 2.08 3.2-8 .. 3..5.3_ 0-13_ 0.20 280.79 4 1.66 2.91 5.77 6.19 0.21 0.27 280.86 -5 2.08 3.74 8.88 9.50 0.31 0.36 280.95 6 2.49 4.57 12.58 13.45 0.44 0.44 281.03 7 2.91 5.40. 16..82. 17_98_ 0..5.8 0.50 281.09 8 3.32 6.23 21.56 23.05 0.75 0.58 281.17 9 3.74 7.06 26.77 28.62 0.93 0.66 281.25 10 4.15 7.89 32.42 34.66 1.12 0.74 281.33 11 3_95 8.10 37_90 40_52. L3j 0.83 281.42 12 3.74 7.69 42.64 45.59 1.47 0.90 281.49 13 3.53 7.27 46.74 49.91 1.59 0.95 281.54 14 3.32 6.85 50.24 53.59 1.68 1.00 281.59 15 3_12 6.44 53-17 56.68_ 1.75 1.03 281.62 16 2.91 6.02 55.56 59.19 1.82 1.06 281.65 17 2.70 5.61 57.44 61.17 1.86 1.09 281.68 18 2.49 5.19 58.83 62.64 1.90 1.10 281.69 19 228 4.78-59-7_6__ 6.3...6.1 1_92_ 1.12 28.1,71 20 2.08 4.36 60.25 64.12 1.94 1.12 281.71 21 1.87 3.95 60.32 64.20 1.94 1.12 281.71 22 1.66 3.53 59.99 63.85 1.93 1.12 281. 71 23. 1 -4.5 3..12 .. 5.928 .. 63...10.. 1_91_ 1.11 281.70 24 1.25 2.70 58.21 61.98 1.88 1.10 281.69 -25 1.04 2.28 56.80 60.50 1.85 1.08 281.67 26 0.83 1.87 55.07 58.67 1.80 1.06 281.65 27 0.62---1.4.5_ 53..__02__ 56.52. 1.75 1.03 281.62 28 0.42 1.04 50.68 54.06 1.69 1.00 281.59 -29 0.21 0.62 48.07 51.31 1.62 0.97 281.56 30 0.00 0.21 45.18 48.27 1.55 0.93 281.52 3.1 0.00 0.00_ 4226 .. 45_18 1.46 0.89 281.48 32 0.00 0.00 39.53 42.26 1.37 0.85 281.44 33 0.00 0.00 36.98 39.53 1.28 0.81 281.40 34 0.00 0.00 34.59 36.98 1.20 0.78 281.37 35 0.00 0.00. 32..35. 3.4...5.9 1.12. 0.74 281.33 36 0.00 0.00 30.26 32.35 1.05 0.71 281.30 37 0.00 0.00 28.30 30.26 0.98 0.68 281.27 38 0.00 0.00 26.47 28.30 0.92 0.65 281.24 39 0.00 0.00 24-76 26-47 0 .. 86 0.63 281.22 40 0.00 0.00 23.16 24.76 0.80 0.60 281.19 41 0.00 0.00 21.66 23.16 0.75 0.58 281.17 42 0.00 0.00 20.26 21.66 0.70 0.56 281.15 43 0.00 0.00 1.8.95 20.26 .. Q_66 0.54 281.13 44 0.00 0.00 17.72 18.95 0.61 0.52 281.11 -45 0.00 0.00 16.57 17.72 0.57 0.50 281.09 Garrett Engineering· 4444 Carter Creetc Paricway Suite 108 ·Bryan. Texas 77802 ·Telephone: (409) 846-2688 ·Fax: (409) 846-3094 • Page 23 -46 0.00. O.OQ 15.5.Q_ 16 . ..5.7 0.54 0.48 281.07 47 0.00 0.00 14.50 15.50 0.50 0.47 281.06 48 0.00 0.00 13.56 14.50 0.47 0.45 281.04 49 0.00 0.00 12.68 13.56 0.44 0.44 281.03 50. 0.00. 0.00 1L8fL 12..6.8. 0.41-0.43 2.8.1.02 51 0.00 0.00 11.09 11.86 0.38 0.42 281.0f -52 0.00 0.00 10.37 11.09 0.36 0.40 280.99 53 0.00 0.00 9.69 10.37 0.34 0.38 280.97 54 0.00. O.OQ 9_06. 9_69 0.32 .. 0.36 2.80.95. 55 0.00 0.00 8.46 9.06 0.30 0.35 280.94 56 0.00 0.00 7.90 8.46 0.28 0.33 280.92 57 0.00 0.00 7.38 7.90 0.26 0.32 280.91 5.8 QJlO 0.00 6_89 7 .. 3-8. 025 __ 0.30 28Q,~9 p9 0.00 O.QO 6.42 6.89 0.23 0.29 280.88 60 0.00 Q.QO 5.~~ 6.4~ 0.22 0.?8 2~0.87 Gar™! Engineering-4444 Carter Creek ParkwaY Suite 108 ·Bryan, Texas 77802-Telei:tx>ne: (409} 846-2688 -Fax: (409} 846-309<1 • Page 24 - Inflow/Outflow Simulation 5-Year Storm Event \ 3.50 -----t--~---+-----+-----+-----t------+------t ' ' 3-.00--'tJ I \ c: o -u Cl) \ "' ~ Cl) 2 .50 D. --· Cl) Cl) u. \ IJ :c G-2..00_--~~~++-~~~--tc-~~~--+~~~--;~~~~-r-~~~-t--~~----i -~ o ... 5 :::s 0- I I I i ! 1.00 J I I I J i ' i o.scr ., t f '! 'i ,t I 0.00 0 10 \ \ \ \ \ \ \ \ ... \ ' \\ \ \ \ \ I \\ ~ 20 30 40 50 Time (Minutes) ·-·-···-··· -Pre-Development Hydrograph • • • Post-Development Outflow Hydrograph Without Detention Post-Development Outflow With Detention - -- ---Post-Development "Free-Flow" 60 Garrett Engneerlng • 4444 Carter CTeel< Parkway S\Jite 108 ·Bryan . Texas 77802 ·Telephone: (409) 846-2688 ·Fax: (409) 846-3094 • Page 25 70 -Inflow I Outflow Simulation 10-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 0.00 0.00 0.00 0.00 0.00 0.00 280.59 1 0.47 0.47 0.40 0.47 0.03 0.11 280.70 2 0.93 1.40 1.65 1.80 0.08 0.15 280.74 3 1.40 2.33. 3.69 3 .. 9.8. Qt4 0.21 280.80 4 1.87 3.26 6.49 6.96 0.23 0.29 280.88 -5 2.33 4.20 9.99 10.69 0.35 0.39 280.98 6 2.80 5.13 14.14 15.12 0.49 0.46 281.05 7 3.26 6.0.6-18.89 2Q20_ 0.6.5 0.54 281.13 8 3.73 6.99 24.21 25.89 0.84 0.62 281.21 9 4.20 7.93 30.06 32.14 1.04 0.71 281.30 10 4.66 8.86 36.41 38.92 1.26 0.80 281.39 11 4.43. 9.0_9 42..56. 45_50_ 1.47 -0.90 281.49 12 4.20 8.63 47.95 51.18 1.62 0.97 281.56 13 3.96 8.16 52.63 56.11 1.74 1.03 281.62 14 3.73 7.69 56.64 60.32 1.84 1.08 281.67 15 3.50 7.23. 60.00 63...86 1.93. 1.12 281.71 16 3.26 6.76 62.76 66.76 2.00 1.15 281.74 -17 3.03 6.29 64.94 69.05 2.06 1.18 281.77 18 2.80 5.83 66.56 70.76 2.10 1.20 281.79 19_ 2.56 5.3.6 67.66. 71.92 .. 2...13. 1.22 281.81 20 2.33 4.90 68.27 72.56 2.15 1.22 281.81 21 2.10 4.43 68.40 72.70 2.15 1.22 281.81 22 1.87 3.96 68.08 72.36 2.14 1.22 281.81 23. 1.63 3.50 67.3.4. 71.58 2.12 1.21 281.80 24 1.40 3.03 66.19 70.37 2.09 1.20 281.79 25 1.17 2.56 64.65 68.75 2.05 1.18 281.77 26 0.93 2.10 62.74 66.75 2.00 1.15 281.74 21 0.70 1.63 60.49 64.3.7 1.9.4 1.13 281.72 28 0.47 1.17 57.90 61.65 1.88 1.09 281.68 29 0.23 0.70 55.00 58.60 1.80 1.06 281.65 30 0.00 0.23 51.80 55.23 1.72 1.02 281.61 31_ 0.00. 0.00 48.53. 51..80. 1.63 0.97 281.56 32 0.00 0.00 45.43 48.53 1.55 0.94 281.53 33 0.00 0.00 42.49 45.43 1.47 0.90 281.49 34 0.00 0.00 39.75 42.49 1.37 0.85 281.44 35 0.00 0.00 3.7 .18 39.75 1.28 0.81 281.40 36 0.00 0.00 34.77 37.18 1.20 0.78 281.37 37 0.00 0.00 32.53 34.77 1.12 0.74 281.33 38 0.00 0.00 30.42 32.53 1.05 0.71 281.30 39. 0.00 0.00 28..46 30.42.. 0.98 0.68 281.27 40 0.00 0.00 26.62 28.46 0.92 0.65 281.24 41 0.00 0.00 24.89 26.62 0.86 0.63 281.22 42 0.00 0.00 23.28 24.89 0.81 0.60 281.19 43 0.00 0.00 21.78. 23...28. 0.75 0.58 281.17 44 0.00 0.00 20.37 21.78 0.70 0.56 281.15 --GarTelt En!jneering-4H4 Carter Creek Part<way Suite 108-Bryan. Texas 7781)2 -Telephone: (409) 846-2688 -Fax: (409) 846-3094 -Pogo 26 -45 0.00 0.00 19.05 20.37 0.66 0.54 281.13 46 0.00 0.00 17.82 19.05 0.62 0.52 281.11 47 0.00 0.00 16.66-17.82 0.58 0.50 281.09 48 0.00 0.00 15.58 16.66 0.54 0.48 281.07 49 0.00 0.00 14.58 15.58 0.50 0.47 281.06 50 0.00 0.00 13.63 14.58 0.47 0.46 281.05 51-0.00 0.00-12.75 13.63 0.44----0.44 281.03 52 0.00 0.00 11.92 12.75 0.41 0.43 281.02 53 0.00 0.00 11.15 11.92 0.39 0.42 281.01 54 0.00 0.00 10.43 11.15 0.36 0.40 280.99 55 °'00-0.00--9.75-1°'43 0-.34-0.38 280.97 56 0.00 0.00 9.11 9.75 0.32 0.36 280.95 57 0.00 0.00 8.51 9.11 0.30 0.35 280.94 58 0.00 0.00 7.95 8.51 0.28 0.33 280.92 59 0.00-0.00-7.42-7-.95 0.26 0.32 280.9_1_ 60 0.00 0.00 6.92 7.42 0.25 0.30 280.89 Garrett Engineering-4444 Carter Cfedc Pall<way Suite 108 -Bryan, Texas 77002 -Telephone: (409) 846-2688 • Fax: (409) 846-3094 -Page 'Z7 -"C c: 0 Inflow/Outflow Simulation 10-Year Storm Event 4 _50-..,._ ____ '+''-------+------t-----t--------t-----r------j . ' J I I ' I I r I I \ I l I I ~ 3 .00 -----1---+---'~--+------+-----r--------;------r-----------j en ... Cl) Q. ' " -Cl) if 2 .so----:--+-----'---+-------+-----1------+-----+-----~ (,,)· I :a :::l f i ! - 0 · ' • I \ ,-,, I 200 ~:~1-I~: ~~~~,~~-\~\~~~~~~~~~~~~ 1 .SQ --__,_____,,___._.... _ ___,,--+_......_ __ +----'_--+-----+-----+-----; : I ,' \ ·.. \ • I \\ ' 1 .00------<--.......... ----+--+----+-------.;f-----+-----+-------1 : I I \ ', ~, :1 \ ~ ~ 0 .50 +..+-V' -#---+----+-----~\, +---~~.!---~-1------1 JI \l I ~ \ o.oo~------1--------e-------+~-----1-------+--------1--------1 0 10 20 30 40 50 Time (Minutes) ------Pre-Development Hydrograph - - -Post-Development Outflow Hydrograph W ithout Detention Post-Development Outflow W it h Detention --• • -·Post-Development "Free-Flow'' 60 Garrett Engnoenng -«44 C.rtor Crook Par1<way Suite 108 • lltyon, Texas 77802-TelePlone: (409) 8-46-2688 -Fax: (409) 846-3094 -P•ge 28 70 Inflow I Outflow Simulation 25-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 0.00 0.00 0.00 0.00 0.00 0.00 280.59 1 0.53 0.53 0.46 0.53 0.04 0.12 280.71 2 1.07 1.60 1.89 2.06 0.08 0.16 280.75 3 1.60 2.66 423 4.55. 0.16 0.22 280.81 4 2.13 3.73 7.43 7.96 0.26 0.32 280.91 5 2.66 4.79 11.43 12.23 0.40 0.42 281.01 6 3.20 5.86 16.17 17.29 0.56 0.49 281.08 7 3.73. 6.92 2L60 23.09 0.75 0.58 281.17 8 4.26 7.99 27.67 29.59 0.96 0.67 281.26 9 4.79 9.05 34.35 36.73 1.19 0.77 281.36 10 5.33 10.12 41.60 44.47 1.44 0.88 281.47 1t 5.06 10.38 48.11 5.L98 1.64 0.98 281.57 12 4.79 9.85 54.96 58.56 1.80 1.06 281.65 13 4.53 9.32 60.40 64.28 1.94 1.12 281.71 14 4.26 8.79 65.06 69.18 2.06 1.18 281.77 ts 3.99 8.25 68 .. 98 73.31 2..._1_6 1.23 281.82 16 3.73 7.72 72.21 76.71 2.25 1.27 281.86 -17 3.46 7.19 74.77 79.40 2.31 1.31 281.90 18 3.20 6.66 76.70 81.43 2.36 1.33 281.92 19. 2.93 6.12 78.03 82.82 2.40 1.35 281.94 20 2.66 5.59 78.78 83.62 2.42 1.36 281.95 -21 2.40 5.06 78.99 83.84 2.42 1.36 281.95 22 2.13 4.53 78.69 83.52 2.42 1.35 281.94 23 1.86 3.99 77.89 82.68 2AO 1.34 28.1.93 24 1.60 3.46 76.63 81.35 2.36 1.33 281.92 -25 1.33 2.93 74.92 79.55 2.32 1.31 281.90 26 1.07 2.40 72.79 77.31 2.26 1.28 281.87 27 0.80 1.86 70..26 74.65 2.20. 1.25 281.84 28 0.53 1.33 67.35 71.59 2.12 1.21 281.80 29 0.27 0.80 64.07 68.15 2.04 1.17 281.76 30 0.00 0.27 60.45 64.34 1.94 1.12 281.71 31 0.00. 0.00 56_76 &OAS 1.85 1.08 281,67 32 0.00 0.00 53.25 56.76 1.76 1.03 281.62 33 0.00 0.00 49.91 53.25 1.67 0.99 281.58 34 0.00 0.00 46.74 49.91 1.59 0.95 281.54 35 0.00 0.00 43.73 46.74 1.51 0.91 281.50 36 0.00 0.00 40.90 43.73 1.41 0.87 281.46' 37 0.00 0.00 38.26 40.90 1.32 0.83 281.42 38 0.00 0.00 35.78 38.26 1.24 0.79 281.38 39 0.0.0 0.00 33 .. 47 35.78 1.16 0.76 281.35 40 0.00 0.00 31.31 33.47 1.08 0.73 281.32 41 0.00 0.00 29.28 31.31 1.01 0.69 281.28 42 0.00 0.00 27.39 29.28 0.95 0.67 281.26 43. 0.00 0.00 25.62 27 .. 39 0.89 0.64 281.23 44 0.00 0.00 23.96 25.62 0.83 0.61 281.20 45 0.00 0.00 22.41 23.96 0.77 0.59 281.18 Garrett Ensjneeting-4444 Carter Creek Pal1<way Suite 108-Bryan, Texas 77802-Telephone: (409) 846-2688 -Fax: (409) 846-3094 -Page 29 -46 0.00_ 0.00 20.9.6 22..41. 0.72_. 0.57 281.16 47 0.00 0.00 19.60 20.96 0.68 0.55 281.14 48 0.00 0.00 18.34 19.60 0.63 0.53 281.12 49 0.00 0.00 17.15 18.34 0.59 0.51 281.10 50 0.0.Q 0.00 16.04. 17.15. 0.56. 0.49 281.08 51 0.00 0.00 15.00 16.04 0.52 0.48 281.07 52 0.00 0.00 14.03 15.00 0.49 0.46 281.05 53 0.00 0.00 13.12 14.03 0.45 0.45 281.04 54 o_oo. 0.00 1.2.27. 13..12.. 0.43 0.43 28.t.02 55 0.00 0.00 11.47 12.27 0.40 0.42 281.01 56 0.00 0.00 10.73 11.47 0.37 0.41 281.00 57 0.00 0.00 10.03 10.73 0.35 0.39 280.98 5.8. 0.00. 0.00 9.3.8 10 .. 03 0.33. 0.37 280.96 59 0.00 0.00 8.76 9.38 0.31 0.35 280.94"-60 0.00 0.00 8.18 8.76 0.29 0.34 280.93 Garrett Engineering· 44H Carter Creek Parkway Slile 108 • Bryan, Texas 77802 ·Telephone: (409) 846-2688 • Fax: (409) 846-3094 • Page 30 5.00 4 .00 -'O c: er u Q) (/) ... Q) Q. ---· Q) Q) 3 .00 u. .~ .c ;:, £ ~ o .. 5 ;:, 0 2.00 1 .00 ' r r • i 0 Inflow/Outflow Simulation 25-Year Storm Event -' ( I I f , j I i f ' ' ' \ ' \ . ' ' ' ' 1 \ \ I / \ I 10 \ \ 20 ' \ ' ' \ \ ' \ \ \ ' 30 40 Time (Minutes) ---------Pre-Development Hydrograph 50 • • -Post-Development Outflow Hydrograph Without Detention Post-Development Outflow With Detention • • -• • ·Post-Development "Free-Flow" 60 Garrett Ens;jneering-4444 Carter Creek Parkway Suite 108 -Bryan , Texas 77802 -T~: (409) 84S.2688 -Fax: ('409) 84&.3094 -Page 31 -70 Inflow I Outflow Simulation 50-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation {Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 0.00 0.00 0.00 0.00 0.00 0.00 280.59 1 0.60 0.60 0.52 0.60 0.04 0.12 280.71 2 1.20 1.81 2.15 2.33 0.09 0.16 280.75 3 1.81 3.01 4.80 5_16_ 0.18 0.24 280.83 4 2.41 4.21 8.42 9.01 0.30 0.35 280.94 5 3.01 5.42 12.94 13.84 0.45 0.44 281.03 6 3.61 6.62 18.30 19.56 0.63 0.53 281.12 7 4.21 7.83 24...43. 26-12. 0.84 0.62 281.21_ 8 4.82 9.03 31.30 33.46 1.08 0.72 281.31 9 5.42 10.23 38.85 41.53 1.34 0.84 281.43 10 6.02 11.44 47.10 50.29 1.60 0.96 281.55 11 5.72 11.74 5522. 5.8_8_3__ 1..8.1 1.06 281.65 12 5.42 11.14 62.37 66.36 1.99 1.15 281.74 -13 5.12 10.53 68.60 72.91 2.15 1.23 281.82 14 4.82 9.93 73.95 78.53 2.29 1.29 281.88 15 4.51 9.33 78A_6 83.28_ 2-41 1.35 281.94 16 4.21 8.73 82.17 87.19 2.51 1.40 281.99 -17 3.91 8.13 85.17 90.30 2.57 1.44 282.03 18 3.61 7.52 87.48 92.69 2.60 1.47 282.06 19 3_31 6.92. 89-14 94-4.t 2.63 1.49 282_.08 20 3.01 6.32 90.16 95.46 2.65 1.50 282.09 21 2.71 5.72 90.57 95.88 2.66 1.51 282.10 22 2.41 5.12 90.38 95.68 2.65 1.51 282.10 23 2.-11 4.51 89.61 94.89 2...6A 1.50 282.09 24 1.81 3.91 88.29 93.52 2.62 1.48 282.07 25 1.50 3.31 86.42 91.60 2.59 1.45 282.04 26 1.20 2.71 84.04 89.13 2.55 1.42 282.01 21 0.9Q 2.11. 81-19 86.15 2.48 1.39 281.98 28 0.60 1.50 77.90 82.69 2.40 1.34 281.93 29 0.30 0.90 74.20 78.80 2.30 1.30 281.89 30 0.00 0.30 70.12 74.50 2.19 1.25 281.84 31 0.00_ 0.00 55_95 70~1.2 2.09 1.19 281.78 32 0.00 0.00 61.98 65.95 1.98 1.14 281.73 33 0.00 0.00 58.21 61.98 1.88 1.10 281.69 34 0.00 0.00 54.63 58.21 1.79 1.05 281.64 35 0.00 0.00 51.23 54.63 1.70 1.01 281.60 36 0.00 0.00 47.99 51.23 1.62 0.97 281.56 37 0.00 0.00 44.91 47.99 1.54 0.93 281.52 38 0.00 0.00 42.01 44.91 1.45 0.89 281.48 39 0.00 0.00 39.29 42.01 1.36 0.85 281.44 40 0.00 0.00 36.75 39.29 1.27 0.81 281.40 41 0.00 0.00 34.38 36.75 1.19 0.77 281.36 42 0.00 0.00 32.16 34.38 1.11 0.74 281.33 43 0.00 0.00 30.08 32_16_ 1.04 0.71 281.30 44 0.00 0.00 28.13 30.08 0.97 0.68 281.27 -45 0.00 0.00 26.31 28.13 0.91 0.65 281.24 Garrett Engneering • 4444 Carter Creel< Parkway Suite 108 -Bryan, Tens 77802 -Telephone: (409) 84&-2688 • Fax: (409) ~3094 -Page 32 -46 0.00 0.00 24.61 26.31 Q.85 0.62 281.21 47 0.00 0.00 23.02 24.61 0.80 0.60 281.19 48 0.00 0.00 21.53 23.02 0.74 0.58 281.17 49 0.00 0.00 20.14 21.53 0:70 0.55 281.14 SQ_ 0.00 0.00 18.8.3. 2Q14. 0.65 0.53 281.12 51 0.00 0.00 17.61 18.83 0.61 0.52 281.fr 52 0.00 0.00 16.47 17.61 0.57 0.50 281.09 53 0.00 0.00 15.41 16.47 0.53 0.48 281.07 54 0.00 0.00 14.41 15.41 0.50 0.47 281.06 55 0.00 0.00 13.48 14.41 0.47 0.45 281.04 56 0.00 0.00 12.60 13.48 0.44 0.44 281.03 57 0.00 0.00 11.79 12.60 0.41 0.43 281.02 58 0.00 0.00 11.02. -11.19 0.38 0.42 281.01 59 0.00 0.00 10.31 11.02 0.36 0.40 280.99 -60 0.00 0.00 9.63 10.31 0.34 0.38 280.97 Garrett Engneering-4444 Carter Creek Pari<way Suite 108-Bryan, Texas 77802 ·Telephone: (409) 846-2688 ·Fax: (409) 846-3094 • Page 33 Inflow/Outflow Simulation 50-Year Storm Event 6 .00 \ I 'l ' \ 5 .00 l :a-t c: 0 c.r Cl.I .. "' \ .... 4 .00 ... Cl.I l Q. .... l Ql .. I ' Cl.I LL I .!::!... ' .Q :J ~ 3 .00 ... \ ~ I \ \ 0 I 5-I :J 0 ! ' 2.00. I r j I l • j \ \ I i \ i • f I \ I I 1 .00-I o .oo -~---..,_ ___ ..,_ ___ .,._ ___ ...._ ___ ...._ ___ ,.._ ___ ,.. 0 Time (Minutes) ·--·---Pre-Development Hydrograph - - -Post-Development Outflow Hydrograph Without Detention ---Post~DevelapmenlO.utflow With Detention ------Post-Development "Free-Flow" Garrett Engineering· 4444 Carter Creek Parltway &ite 108 ·Bryan, Texas nW2-Telephone: (409) 114&.2688 ·Fax: (409) 846-3094 -Page 34 -Inflow I Outflow Simulation 100-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 0.00 0.00 0.00 0.00 0.00 0.00 280.59 1 0.63 0.63 0.55 0.63 0.04 0.12 280.71 2 1.26 1.89 2.25 2.44 0.09 0.17 280.76 3 1.89 3.14 5.02. 5.39 0.19 0.25 280.84 4 2.51 4.40 8.80 9.42 0.31 0.36 280.95 5 3.14 5.66 13.52 14.46 0.47 0.45 281.04 6 3.77 6.91 19.11 20.43 0.66 0.54 281.13 7 4.40_ 8.17 25 .. 52_ 21.28. 0.88 0.64 281.23 8 5.03 9.43 32.69 34.94 1.13 0.75 281.34 9 5.66 10.68 40.57 43.37 1.40 0.87 281.46 10 6.29 11.94 49.21 52.51 1.65 0.98 281.57 11 5.97 12.26. 57.72_ 6.t.46 t.87. 1.09 281.68 12 5.66 11.63 65.22 69.35 2.07 1.18 281.77 13 5.34 11.00 71.74 76.22 2.24 1.27 281.86 14 5.03 10.37 77.35 82.12 2.38 1.34 281.93 15 4.71 9.74 82Jl9. 87..09. 2..50 1.40 281.99 16 4.40 9.11 86.04 91.20 2.58 1.45 282.04 17 4.09 8.48 89.25 94.52 2.63 1.49 282.08 18 3.77 7.86 91.76 97.11 2.68 1.53 282.12 19 3.46. 7.23 93.57 98_9_9 2.71 1.55 282.14 20 3.14 6.60 94.72 100.17 2.73 1.57 282.16 -21 2.83 5.97 95.22 100.69 2.74 1.57 282.16 22 2.51 5.34 95.09 100.56 2.73 1.57 282.16 23 2.20 4.71 94.36 99.81 2.72 1.56 282.15 24 1.89 4.09 93.05 98.45 2.70 1.54 282.13 25 1.57 3.46 91.17 96.51 2.67 1.52 282.11 26 1.26 2.83 88.75 94.00 2.63 1.49 282.08 27 0.94 2.20 85.80 90.9.5 2.58. 1.45 282.04 28 0.63 1.57 82.35 87.37 2.51 1.40 281.99 29 0.31 0.94 78.47 83.29 2.41 1.35 281.94 30 0.00 0.31 74.19 78.78 2.30 1.30 281.89 31 0.00 0.00 69.81. 74_19 2.j9 1.24 281.83 32 0.00 0.00 65.66 69.81 2.08 1.19 281.78 33 0.00 0.00 61.71 65.66 1.98 1.14 281.73 34 0.00 0.00 57.95 61.71 1.88 1.09 281.68 35 0.00 0.00 54 .. 38 57.95.. 1.78 1.05 281.64 36 0.00 0.00 50.99 54.38 1.70 1.01 281.60 -37 0.00 0.00 47.77 50.99 1.61 0.96 281.55 38 0.00 0.00 44.70 47.77 1.53 0.93 281.52 39 0.00 0.00 41.81 44.70 1.44 0.89 281.48 40 0.00 0.00 39.11 41.81 1.35 0.84 281.43 41 0.00 0.00 36.58 39.11 1.26 0.81 281.40 42 0.00 0.00 34.22 36.58 1.18 0.77 281.36 43 0.0.0 0.00 __ 32.QQ 34.22. 1.11 0.74 281.33 44 0.00 0.00 29.93 32.00 1.03 0.70 281.29 45 0.00 0.00 28.00 29.93 0.97 0.67 281.26 Garrett Engineering-4444 Carter Creek Pali<way Suite 108-Bryan, Texas 77802-Telephooe: (409) 846-2688 -fax; (409) 846-3094 -Page 35 -46 0.00 O.OQ 26.19_ 28.00_ 0.91 0.65 281.24 47 0.00 0.00 24.49 26.19 0.85 0.62 281.21 48 0.00 0.00 22.91 24.49 0.79 0.60 281.19 49 0.00 0.00 21.43 22.91 0.74 0.57 281.16 50 O.QO 0.00 2o.__04 21.43 0.69 0.55 281_.14 51 0.00 0.00 18.74 20.04 0.65 0.53 281.12 52 0.00 0.00 17.53 18.74 0.61 0.51 281.10 53 0.00 0.00 16.40 17.53 0.57 0.50 281.09 54 0.00. -0.00 15-3-3__ 16..40 0.53 0.48 281,07 55 0.00 0.00 14.34 15.33 0.50 0.47 281.06 -56 0.00 0.00 13.41 14.34 0.46 0.45 281.04 57 0.00 0.00 12.54 13.41 0.43 0.44 281.03 58 0.00 0.00 11.73__ 12.54 0.41 -0.43 281 .02 59 0.00 0.00 10.97 11.73 0.38 0.41 281.00 ' 60 0.00 0.00 10.26 10.97 0.36 0.40 280.99 Garrett Er9neering· 4444 Carter Creek Parl<way Suite 108 -Bryan, Texas 77802 -Telephone: (409) 846-2688 ·Fax: (409) 846-3094 • Page 36 -"C c o --u Cl.I Inflow/Outflow Simulation 100-Year Storm Event 7 .00 ------------~---~--~---~--~ \ 6Jl0_ ...... _------ttt--.-\----+--------t-----+-----+------+--------t ' '- 1 \ 5.01-,_..--~---+--------+-----+-------+-----+-----+--------' ' t ' 'l ~ 4-.00 -.. ------1-----'--+------+-------+------+-------t-------t Cl.I 0.. ----Cl.I Cl.I LL .!:t .c :J I , \ ' ~ 3 .00 -------<-+-->-------<fT------+-----+-------+-----+-------< ~ Q _ = :J Q__ 0 40 Time (Minutes) ----------Pre-Development Hydrograph 50 - - -Post-Development Outflow Hyd rograph Without Detention Post-Development Outflow W ith Detention -- - - - -Post-Developme nt "Free -Flow" 60 Garrett Engneering-4444 Carter Creek Par1<way SUite 108-Bryan, Texas 77802 -Telephone : (409) 846-2688 -Fax: (409) 846-3094 -Page 37 70 - -"C· c: 0 2.00 1.8f>- 1 .60 1.40 ~-t.20 "' ... Cl) a. .... Cl) if-r.aa - u :c... :::s 2. ~ 5 0.80 ~ 0 0 .60 0.40- 0.20 0.00 Inflow/Outflow Simulation 2-Year Storm Event -· i\ j\ ~ \ i \ I \ / """"" \ I \( \ r I f I \ ( i , I \ i \ \ ! \ t ' \ J l f \ -\ I i I \ I \ '-· I { \ \ i \ i l \ i \ 1 \ \ r I \ I \ f \. I \ \ \ I \ i i I J \ ~ \ ' \ \ v \ ~ \ \ '. l 0 10 20 30 40 50 60 70 Time (Minutes) ··--·---Pre-Development Hydrograph -Total Post-Development Hydrograph Garrett Engneefing-4444 CarterCreekPllri<way Swe 106 -lll)on, Texas 77602 • T~: (409)646-2688 -Fax: (409) 646-3094 -Page 38 -"C c 0 (.) Q) en .... Q) Q. --Q) Q) u. (.) :0 ::I 0--~ 0 --= ::I 0 -- Inflow/Outflow Simulation 5,.vear Storm Event 2 .00 ------+-+~---+-----+------+----+----+------I 1 .50 1-:(){} J I I I f l I I I ! i I I I I 1 i I I i ' 10 \ \ \ 20 \ \ \ \ \ l 30 40 50 60 Time (Minutes) -··-·-·--Pre-Development Hydrograph. -Total Post-Development Hydrograph Garrell Engineering-4444 Carter Creek Parkway SUite 108-Bryan, Texas 77802 ·Telephone: (4 09) 846-2688 ·Fax: (409) 846-3094 • Page 39 70 Inflow/Outflow Simulation 10-Year Storm Event 2 .50 \ I\ I , j \ 2 .00 "C / c: 0 u GI rJ) ......... GI a.. I --f ~ GI 1 .50 LL u I :c·-\ ::I ~ I ! \ 3: \ 0 I =---I \ ::I i 0 t \ 1.00 i , \ I I \ I ' f I \ I \ \ 1 I I \ 0 .50 j I \ \ \ \ \ \ \ \ O:()(J. 0 10 20 30 40 50 60 70 Time (Minutes) --Pre-Development Hydrograph -Total Post-Development Hydrograph Garrett Ef9neering-44-44 Carter Creek Par1<way Suite 108 -Btyan, Texas 77802 -Telephone: (409) 846-2688 -Fax: (409) 848-3094 -Page 40 - 2 .50 2 .00 -'C c- 0 c.J (1) Cfr• '-(1) a._ -(1) if-t.5o_ c.J :a ::J_. ~ ?; 0 s :::J 0 1.00 Inflow/Outflow Simulation 25-Year Storm Event I I I i ' I i : i l I i I ! .\ /\ I ! I I ! ! j i \ \ \ \ \ \ ' \ \. \ \ \ O:Oe..----+----1-------1~----t----t-----1----o'!f 0 10 20-3Q.. 40 50 60 . 70 Time (Minutes) ·Pre-Development Hydrograph -Total Post-Development Hydrograph Garrett Engineenng· 4444 Carter Creek Po rl<wily Suite 108 -Bryan, Texa s 77802 • Tetei:l»ne: (409) 848-2688 -Fax: (409) 846-3094 -Page 41 :a-c: o · u Q) UJ ... Q) D. --Q) Q) u. u · :a :::s (;) -~ o . = :::s o . 3.00 2 .50 2 .0(} 1.50 1.00 0 .50 lnflow/Outflo.w . .Simulation so,. Year Storm Event 11. '\ i I i I I I j j J ' i i ; l ! i i ! i I J \ \ t r t I i I I I I ' i i I I I I . I i I \ \ \ \ \ \ \ \ \ \ \ \ o .oo -¥----+----t-----"'l~----1------+---_,.._ __ ...... 0 10 20 30 40 50 60 70 Time (Minutes) ·---Pre-Development Hydrograph -Total Post-Development Hydrograph Garrett Engneering • 4444 Carter Creek Pal1<way Suite 108 • ll<)'an, Texas 77802 • Teleitione: (409) 84&-2688 • Fax: (409) 84&-3094 · Page 42 Inflow/Outflow Simulation 100-Year Storm Event I I -f ~ I ~ i \ ~-2 .00 ._---i---J-jl----\.--l-----l-~---+-----+-----+------1 {. I ~ I F i \ \ l ::I I ~1.so ·-~·._____,i~~J+.-..~~~-+-'...-~~--1~~~--+-~~~-1-~~~--1~~~~ ~ . i 0 1 . ~-II \ I \ 1 .00---,>.,~--tf--+-~~~-+~-+-~~--t-~~~~+-~-t---~--t~~~~-t-~~~--1 I \ \ \ .\ o.so~.__ ......... ~-+-~~~--1~~--1...-+-~~~-+-~~~--1~__,.--~+-~~~~ \ ' \ i \ CJ.00-1· ----t-----+----..;i....----+-----+-----1-------t 0 10 20 30 40 50 60 70 Time (Minutes) --...... Pre~Development Hydr.ograp tt -Total Post~D.evelopment Hydrograph Garrett E"!ineering • 4444 Carter Creek Parkway Suite 108 -Bryan, Texas 77802 -Telephone: (409) 846-2688 -Fax: (409) 846-3094 -Page 43 Detention Pond Storage Volumes as Percent of Maximum Volume 70% Q) E- ::::s 0 60% > E ::::s e- ')( cu 50% ~-.... 0 _. c: 40% Q) u ,__ Q) Q. 30% 2-year 5-year 10-year 25-year 50-year 100-year Design Storm Storm Simulation Synopsis 2-year 5-ear 10-y.ear 25-year 50-year 100-yea[ Storm Depth 0 .98 1.12 1.22 1.36 1.51 1.57 Stonn-Elevation 281 . .S.7-2a1.,11 . 281 .S.1 281 .95 282 .10 282 .16.- Storm Volume 1512 1868 2116 2442 2797 2939 Maxi mum-Capacity 4011 -4&11 401-1 4011 4011 4011 Percent of Capacity 38% 47% 53% 61% 70% 73% Garrett Engineering· «44 Carter Creek Part<woy Suite 108 • Bryon, Texas 77802 -Telephone: (409) 846-2688 -Fox: (409) 846-3094 -Page «