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HomeMy WebLinkAbout28 Development Permit 315 Neatherlin StorageDRAINAGE COMPUTATIONS for NEATHERLIN SELF STORAGE COMPLEX 4004 South Texas A venue College Station, Brazos County, Texas Prepared for Kenneth Neatherlin P.O. Box 3321 Bryan, Texas 77805 Telephone: (409) 778-4663 Prepared by .· Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 * Revised November 1995 * /'lP f~~ r .,,; ,, ~ . -rl.. Mf(t) 'r. DRAINAGE COMPUTATIONS for NEATHERLIN SELF STORAGE COMPLEX 4004 South Texas A venue College Station, Brazos County, Texas Pr epared for Kenneth Neatherlin P.O. Box 3321 Bryan, Texas 77805 Telephone: {409) 778-4663 Pr epared by .· Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan , Texas 77802 Telephone: {409) 846-2688 DRAINAGE COMPUTATIONS for NEATHERLIN SELF STORAGE COMPLEX 4004 South Texas A venue College Station, Brazos County, Texas *Revised November, 1995 * SUMMARY The project is situated at 4004 South Texas Avenue in southern College Station and is the intended site for a self-storage complex. The complex will be an expansion of the existing Neatherlin facility and is to be established within the bounds of a 3.33 acre tract. The original Neatherlin complex is located on the northwestern adjacent property and shares the same drainage swale that runs between the properties. This report is divided into two parts. The first section concerns the natural drainage swale previously mentioned located at the northwestern side of the project site. The second part of the report covers drainage information relating to the overall site and the discharge to the bar ditch along the Highway 6 Access Road. EXISTING SW ALE The analysis of the swale shows the changes and impacts of the proposed new development to the drainage basin contributing to this swale. The pre-development basin was calculated to be 6.25 acres and is shown on the following drainage map. The total runoff generated from this area was broken down according to the following: 5.05 acres with a undeveloped runoff coefficient of 0.40 and 1.20 acres with a conservative runoff coefficient of 0.90. The corresponding flow rates are shown in the calculations and compared to the post-development conditions . The total post-development area was computed at 7.23 acres and is also shown on a drainage map included in this report. Of this total, the runoff coefficients are as follows: 4 .23 acres at 0.40, 1.80 acres ("free- flowing" from the project site) at 0.50 , and 1.20 acres (from adjacent Neatherlin site) at 0.90. The value of 0 .50 was chosen as a conservative account for the influence of the temporary buildings in the northern part of the property . (These buildings will etfect the runoff behavior somewhat but will not create the nearly impermeable conditions associated with permanent structures. The temporary buildings will be up on blocks and allow runoff flow and infiltration beneath them. Essentially the only increasing drainage effect of the temporary buildings is in concentrating runoff around each building's perimeter. However this water will be dissipated upon reaching the ground and follow natural surface flow patterns .) Calculations for flow capacity of the swale were performed and compared to the above peak flow rate requirements. The capacity of the swale was found to be sufficient to handle the expected peak flow rates even for the 100-year storm event. The velocities at these peak flow conditions were also checked to verify that the grass covering will be acceptable and not induce undesirable erosion . Velocities in the swale range from 2 ft/s to an ultimate maximum of 4 ft/s. '\. PROJECT SITE & BAR DITCH The drainage area tributary to this analysis is the total project site of 3.33 acres. The pre-development run-off coefficient was estimated to be 0.40. Assuming a worst case scenario, the entire developed area of 1.23 acres was considered impervious with a post-development run-off coefficient of 0.90. A detention facility will be constructed in the southwestern portion of the property in keeping with the existing contours and optimal flow patterns. 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. In this case, the detention pond will collect, store and meter run-off from 1.23 acres, the developed area of the project site. Since all generated runoff from the developed surface area will be routed through the pond, "free-flow" will consist of the remaining 2.10 acres of the site with a conservative runoff coefficient of 0.50 -comparable to the original pre-development value of 0.40. (As mentioned, this value of 0.50 was chosen to account for the influence of the temporary buildings in the northern part of the property. These buildings will (lffect the runoff behavior somewhat but will not create the nearly impermeable conditions associated with permanent structures. The temporary buildings will be up on blocks and allow runoff flow and infiltration beneath them. Essentially the only drainage effect of the temporary buildings is in concentrating roof runoff around each building's perimeter, but this water will be dissipated upon reaching the ground and follow natural surface flow patterns.) These report calculations are summarized according to the following methodology. Beginning on page 3, based on the total tributary drainage area of the project (3.33 acres), the pre-development run-off coefficient (assumed 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. Computations on page 4 are based on the tributary area of 3.33 acres, the post-development run-off coefficient of 0.90, a minimum time of concentration of 10 minutes, to yield the relative pre-development peak discharge rate ("Q"). 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. The "C" variable is the run-off coefficient (In the post-development condition "C" is assumed to be 0.90. Generally, the post-development coefficient is weighted according to the relative amounts of pervious and impervious surface area. "I" represents the rainfall intensity in inches per hour, and similarly "A" is the area of the basin in acres. Comparison of the peak pre-development discharge rate to the post-development discharge rate is included in the report to aid the designer in establishing a preliminary "target" of detention volume required. This preliminary estimate is determined as the volume difference generated between the pre-development and post-development hydrographs. (See pages 11-13 for pre-development and post-development hydrographs.) Please note that the post-development hydro graph shown on these same graphs assumes no detention at all, therefore reflecting the scenario that there is no lag in runoff discharge and all water is allowed to "free-flow" unrestricted off the property. Pages 5 and 6, respectively, provide information concerning the post-development run-off that is not routed through the detention facility , "free flow", and the post-development run-off that is routed through the detention facility and retained on site. Page 7 and page 8 are tabulations of the pre-development and the post-development hydrographs based on the computations performed on pages 3 & 4. The post-development hydrograph assumes no detention to facilitate direct comparison in the pre-and post-development conditions. Pages 9 & 10 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 6 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 10 is 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 to the relative 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 14 presents a data tabulation and a depth versus volume graph of the detention facility. Page 15 supplies a tabulation and a rating curve for the proposed outlet control structure. A circular pipe culvert was chosen for the outlet control structure due to the discharge ratio characteristics associated with the anticipated headwater depth. A pipe diameter of 12 inches (1.0 ft) was selected. This value was determined from the following equation for headwater depth (in feet), H = [ [ ( 2.5204 ( 1 + K)) I D4] + [ ( 466.18 n 2 L ( 1 + K)) I Dl613]] x (DI 10 )2. "K" is the entrance loss coefficient ( K = 0.50 for this case). "D" is the diameter of the pipe in feet. "L" is the length of culvert in feet. "Q" is the design discharge rate in cubic feet per second. "n" is manning's roughness coefficient, and "H'' is the headwater depth in feet The outlet control structure will release the detained water from the pond to the adjacent bar ditch along the Texas State Highway 6 Access Road. The maximum rate of discharge, in the 100-year storm event, will be 3.1 ft3/sec. We do not anticipate any problems with either the capacity of the bar ditch or the corresponding velocities as these flows are mild and in keeping with existing conditions. Page 16 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 14 is a graphical solution to the equation presented in the "Draina~e Policy And Desj~n Standards" as follows: 2s1 (I1 +Ii)+(----------------01) dt 2s2 = (-----------------+ Oi) dt Page 17 through page 28 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 in the table and is the time at during which this maximum depth occurs from the onset 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 can be found in the table. 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 Page 29 through page 34 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 seen from these same hydrographs that the post-development peak discharge rates have been slightly decreased in comparison to the 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 both the detention pond outlet control structure and project site are controlled to be less than the pre-development peak discharge rates with the use of the proposed detention facilities. Subsequent peak post-development discharge velocities are projected to be within manageable limits. EXISTING SW ALE Impact Analysis Neatherlin. Self-Storage Complex -4004 South Texas A venue . 1 j EXISTING SW ALE Impact Analysis Neatherlin . Self-Storage Complex -4004 South Texas Avenue Capacity Calculations EXISTING SWALE (CHANNEL) CAPACITY: Where, Where, Q = (1.486) (1/n) A R2/3 sl/2 (Manning's Equation) Q = Flow Rate (ft3/s) A = Cross-Sectional Area of Flow (ft2) R = Hydraulic Radius (ft) S = Channel Slope (ft per ft) n = Manni ng's Coefficient A = ( b + zy) y (Trap ezaidal Chann el Area Equation) A = Cross-Sectional Area of Flow (ft2) b = Width of Channel Bottom (ft) z = Side Slopes (ft/ft) y = Channel Depth or Flow Depth (ft) Peak Flow Rates (Q) for Related Drainage Basin: PRE-DEVEOPMENT Q 25 Yr Storm = 30.57 ft3/s (cubic feet per second) Q 50 Yr Storm = 34.56 ft3/s (cubic f eet per second) Q 100 Yr Storm = 36 .0 8 ft3/s (cubic feet per second) POST-DEVEOPMENT Q 25 Yr Storm = 36.21 ft 3/s (cubic f eet per second) Q = 40.93 ft3/s (cubicfieetper second) 50 Yr Storm Q 100 Yr Storm = 42.74 ft 3/s (cubic feet per second) PRE -TO POST-DEVEOPMENTINCREASE Q25Yr Storm = 5 .64ft3/s (cubicfeetpersecond) Q 50 Yr Storm = 6.38 ft3/s (cubic f eet per second) Q lOOYr Storm = 6.66 ft3/s (cubicfeetpersecond) Neatherlin . Self-Storage Complex -4004 South Texas Avenue Peak Flow Rates (Q) for Swale: Drainage Basin: 7.23 acres Run-off Coefficient: 0.40 ~ assumes detention will be required with development upstream Time of Concentration: tic path = 1000 feet slope = ± 2.00% velocity = 2.0 ft/sec 1000 ft/ 2.0 ft/sec = 500 seconds = 8.3 minutes DESIGN STORM FREQUENCY: 50 YEAR I 50 = (98) I (8.3 + 8.5)0 .745 = 11.97 in/hr (Intensity) Q 50 = CIA = (0.40)(11.97)(7.23) = 34.6 ft3/s (Flow Rate) Q so Yr Storm = 34.6 ft3/s (Flow Rate) APPROXIMATE CHANNEL CAPACITY: at 1.5 foot depth A = ( b + zy ) y (Trapezaidal Channel Area Equation) A = ( 5.0 + 5 .0*1.5) 1.5 = 18.75 ft2 R = NP (Hydraulic Radius) where P = b + 2y( 1 + z2 )112 (Wetted Perimeter) R = (18.75 ft2) / 5.0 + 3 ( 1+52 )112 = 0.92 ft2 Q = (1.486) (1/n) A R2/3 s112 (Manning's Equation) Q = (1.486) (110.045) (18.75 ft2) (.92)2/3 (0.015)112 = 71.7 ft3/s Q = 71.7 ft3/s (Flow Capcity of Channel) VERIFY CAPACITY: Q 50 Yr Storm = 34.6 ft3/s Q Channel Flow = 71.7 ft3/s Q Channel Capacity = 71.7 ft3/s is greater than Q 50 Yr Storm = 34.6 ft3/s " Cfuck DETERMINE VELOCITY: Q = VA ~ V = 34.6 ft3/s I 18.75 ft2 = 1.84 ft/s Q = VA ~ V = 71.7 ft3/s I 18.75 ft2 = 3.83 ft/s Channel Velocity will be in the range of 2 to 4 ftls " Cfuck Neatherlin. Self-Storage Complex -4004 South Texas Avenue l ' Tributary Area ("A "): 6.25 Acres Pervious Area : 5.05 Acres Impervious Area : 1.2 Acres Run-Off Coefficient ("Cwt"): 0.50 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 : Ho urly Intens it y Rates ("I "): 2-Year: 6.33 5-Year: 7.69 10-Year: 8.63 25 -Yea r: 9.86 50-Year: 11 .15 100-Year· 11.64 Peak Discharge Rate ("Q "): 2-Year: 19 .61 5-Year: 23 .85 10-Year: 26 .77 25-Year: 30 .57 50 -Year: 34 .56 100-Year: 36 .08 C= 0.40 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 Determine R-0st-dew~lopment ~eeak storm..,viater .lflischa~ ~ No ,Detention Tributary Area ("A"): 7 .23 Acres Pervious Area: 4.23 Acres C= 0 .40 C= 0.66 Impervious Area : 3.00 Acres Run-Off Coefficient ("Cwt"): 0.51 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: 23.23 Cubic Feet I Second 5-Year: 28 .25 Cubic Feet I Second 10-Year: 31.71 Cubic Feet I Second 25-Year: 36 .21 Cubic Feet I Second 50-Year: 40.93 Cubic Feet I Second 100-Year: 42.74 Cubic Feet I Second Predevelopment Post-Development Increase 2-Year: 19 .61 Ft3/sec 23 .23 Ft3/sec 3.62 Ft3/sec 5-Year: 23.85 Ft3/sec 28 .25 Ft3/sec 4.40 Ft3/sec 10-Year: 26 .77 Ft3/sec 31.71 Ft3/sec 4.94 Ft3/sec 25-Year: 30 .57 Ft3/sec 36.21 Ft3/sec 5 .64 Ft3/sec 50-Year: 34 .56 Ft3/sec 40.93 Ft3/sec 6.38 Ft3/sec 100-Year: 36 .08 Ft3/sec 42.74 Ft3/sec 6.66 Ft3/sec PROJECT SITE and Discharge to Bar Ditch along Access Road Neatherlin. Self-Storage Complex -4004 South Texas Avenue . PROJECT SITE and Discharge to Bar Ditch along Access Road Neatherlin. Self-Storage Comp lex -4004 South Texas Avenue Determine Total Pre-Devel opm ent Peak St orm Water Discharge Rates Tributary Area ("A"): 3.33 Acres Pervious Area: 3 .33 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: 6.33 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: 8.43 5-Year: 10.25 10-Year: 11.50 25-Year: 13.14 50-Year: 14 .85 100-Year: 15.50 P age3 c = 0.40 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 .0 0 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 "): 3 .33 Acres Pervious Area : 2.10 Acres Impervious Area : 1.23 Acres Run-Off Coefficient ("Cwt"): 0.65 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 .50 C= 0 .90 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Peak Discharge Rate ("Q "): 2-Year: 13 .65 Cubic Feet I Second 5-Year: 16 .59 Cubic Feet I Second 10-Year: 18.62 Cubic Feet I Second 25-Year: 21 .27 Cubic Feet I Second 50-Year: 24 .05 Cubic Feet I Second 100-Year: 25 .11 Cubic Feet I Second Comparison Of Predevelopment And Post-development Pea k Discharge Rates Predevelopment Post-Development 2-Year: 8.43 Ft3/sec 13 .65 Ft3/sec 5-Year: 10.25 Ft3/sec 16 .59 Ft3/sec 10-Year: 11 .50 Ft3/sec 18 .62 Ft3/sec 25-Year: 13 .14 Ft3/sec 21 .27 Ft3 /sec 50 -Year: 14.85 Ft3/sec 24 .05 Ft3/sec 100-Year: 15 .50 Ft3/sec 25.11 Ft3/sec Preliminary Determination Of Detention Pond Volume 2-Year: 5 .22 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 5-Year: 6.35 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 10-Year: 7 .12 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 25-Year: 8 .14 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 50-Year: 9.20 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 100-Year: 9.60 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = P a g e 4 Increase 5 .22 Ft3/sec 6.35 Ft3/sec 7 .12 Ft3/sec 8.14 Ft3/sec 9 .20 Ft3/sec 9.60 Ft3/sec 4,697 Cubic 5 ,712 Cubic 6,411 Cubic 7,322 Cubic 8,277 Cubic 8 ,642 Cubic Feet Feet Feet Feet Feet Feet Determine Post-Development 11 Free-Flow 11 Peak Storm Water Discharge Tributary Area ("A"): 2 .10 Acres Pervious Area : 2.10 Acres Impervious Area : 0.00 Acres Run-Off Coefficient ("Cwt"): 0 .50 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: 6.64 5-Year: 8.08 10-Year: 9.07 25-Year: 10.35 50-Year: 11.71 100-Year: 12.22 Page 5 C= 0 .50 C= 0 .90 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"): 1.23 Acres Pervious Area: 0.00 Acres Impervious Area: 1.23 Acres Run-Off Coefficient ("Cwt"): 0 .90 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: 7 .00 5-Year: 8.52 10-Year: 9.56 25-Year: 10.92 50-Year: 12.34 100-Year: 12 .88 Page 6 C= 0.40 C= 0 .90 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 0.84 1.02 1.15 1.31 1.48 1.55 2 1.69 2.05 2.30 2.63 2.97 3.10 3 2.53 3.07 3.45 3.94 4.45 4.65 4 3.37 4.10 4.60 5.25 5.94 6.20 5 4.21 5.12 5.75 6.57 7.42 7.75 6 5.06 6.15 6.90 7.88 8.91 9.30 7 5.90 7.17 8.05 9.19 10.39 10.85 8 6.74 8.20 9.20 10.51 11.88 12.40 9 7.58 9.22 10.35 11.82 13.36 13.95 Peak=> I 10 8.43 10.25 11.50 13.14 14.85 15.50 11 8.01 9.73 10.93 12.48 14.11 14.73 12 7.58 9.22 10.35 11.82 13.36 13.95 13 7.16 8.71 9.78 11.17 12.62 13.18 14 6.74 8.20 9.20 10.51 11.88 12.40 15 6.32 7.69 8.63 9.85 11.14 11.63 16 5.90 7.17 8.05 9.19 10.39 10.85 17 5.48 6.66 7.48 8.54 9.65 10.08 18 5.06 6.15 6.90 7.88 8.91 9.30 19 4.63 5.64 6.33 7.22 8.17 8.53 20 4.21 5.12 5.75 6.57 7.42 7.75 21 3.79 4.61 5.18 5.91 6.68 6.98 22 3.37 4.10 4.60 5.25 5.94 6.20 23 2.95 3.59 4.03 4.60 5.20 5.43 24 2.53 3.07 3.45 3.94 4.45 4.65 25 2.11 2.56 2.88 3.28 3.71 3.88 26 1.69 2.05 2.30 2.63 2.97 3.10 27 1.26 1.54 1.73 1.97 2.23 2.33 28 0.84 1.02 1.15 1.31 1.48 1.55 29 0.42 0.51 0.58 0.66 0.74 0.78 30 0.00 0.00 0.00 0.00 0.00 0.00 Page 7 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 1.36 1.66 1.86 2.13 2.40 2.51 2 2.73 3.32 3 .72 4 .25 4 .81 5.02 3 4 .09 4.98 5.59 6.38 7 .21 7 .53 4 5.46 6.64 7.45 8.51 9 .62 10.04 5 6.82 8.30 9.31 10.64 12 .02 12.55 6 8.19 9.96 11.17 12.76 14.43 15.06 7 9 .55 11 .62 13 .04 14 .89 16.83 17.57 8 10.92 13 .27 14.90 17.02 19.24 20 .08 9 12 .28 14.93 16.76 19 .14 21 .64 22 .60 Peak=> 10 13.65 16.59 18.62 21.27 24.05 25.11 11 12 .96 15.76 17.69 20 .21 22.84 23 .85 12 12 .28 14 .93 16 .76 19 .14 21 .64 22 .60 13 11 .60 14.10 15.83 18.08 20 .44 21.34 14 10.92 13 .27 14.90 17.02 19 .24 20.08 15 10.23 12 .45 13 .97 15 .95 18 .03 18.83 16 9.55 11 .62 13 .04 14 .89 16 .83 17.57 17 8.87 10.79 12.11 13 .83 15.63 16.32 18 8.19 9 .96 11 .17 12 .76 14.43 15.06 19 7 .51 9 .13 10.24 11 .70 13.23 13.81 20 6.82 8.30 9 .31 10 .64 12 .02 12 .55 21 6.14 7.47 8.38 9 .57 10 .82 11 .30 22 5.46 6.64 7.45 8.51 9 .62 10 .04 23 4 .78 5 .81 6.52 7.44 8.42 8.79 24 4 .09 4.98 5.59 6.38 7 .21 7 .53 25 3.41 4.15 4 .66 5 .32 6.01 6.28 26 2 .73 3 .32 3.72 4 .25 4 .81 5 .02 27 2.05 2.49 2.79 3 .19 3 .61 3 .77 28 1.36 1.66 1.86 2.13 2.40 2 .51 29 0 .68 0.83 0.93 1.06 1.20 1.26 30 0 .00 0.00 0.0 0 0 .00 0 .00 0 .00 P a ge 8 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 0.66 0.81 0.91 1.04 1.17 1.22 2 1.33 1.62 1.81 2.07 2.34 2.44 3 1.99 2.42 2.72 3.11 3.51 3.67 4 2.66 3.23 3.63 4.14 4.68 4.89 5 3.32 4.04 4.53 5.18 5.85 6.11 6 3.99 4.85 5.44 6.21 7.02 7.33 7 4.65 5.65 6.35 7.25 8.19 8.55 8 5.31 6.46 7.25 8.28 9.36 9.78 9 5.98 7.27 8.16 9.32 10.53 11.00 Peak=> I 10 6.64 8.08 9.07 10.35 11.71 12.22 11 6.31 7.67 8.61 9.84 11.12 11.61 12 5.98 7.27 8.16 9.32 10.53 11.00 13 5.65 6.87 7.71 8.80 9.95 10.39 14 5.31 6.46 7.25 8.28 9.36 9.78 15 4.98 6.06 6.80 7.77 8.78 9.17 16 4.65 5.65 6.35 7.25 8.19 8.55 17 4.32 5.25 5.89 6.73 7.61 7.94 18 3.99 4.85 5.44 6.21 7.02 7.33 19 3.65 4.44 4.99 5.70 6.44 6.72 20 3.32 4.04 4.53 5.18 5.85 6.11 21 2.99 3.63 4.08 4.66 5.27 5.50 22 2.66 3.23 3.63 4.14 4.68 4.89 23 2.32 2.83 3.17 3.62 4.10 4.28 24 1.99 2.42 2.72 3.11 3.51 3.67 25 1.66 2.02 2.27 2.59 2.93 3.06 26 1.33 1.62 1.81 2.07 2.34 2.44 27 1.00 1.21 1.36 1.55 1.76 1.83 28 0.66 0.81 0.91 1.04 1.17 1.22 29 0.33 0.40 0.45 0.52 0.59 0.61 30 0.00 0.00 0.00 0.00 0.00 0.00 Page9 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 0.70 0.85 0.96 1.09 1.23 1.29 2 1.40 1.70 1.91 2.18 2.47 2.58 3 2.10 2.55 2.87 3.28 3.70 3.87 4 2.80 3.41 3.82 4.37 4.94 5.15 5 3.50 4.26 4.78 5.46 6.17 6.44 6 4.20 5.11 5.74 6.55 7.40 7.73 7 4.90 5.96 6.69 7.64 8.64 9.02 8 5.60 6.81 7.65 8.73 9.87 10.31 9 6.30 7.66 8.60 9.83 11.11 11.60 Peak=> I 10 7.00 8.52 9.56~ 10.92 12.34 12.88 11 6.65 8.09 9.08 10.37 11.72 12.24 12 6.30 7.66 8.60 9.83 11.11 11.60 13 5.95 7.24 8.12 9.28 10.49 10.95 14 5.60 6.81 7.65 8.73 9.87 10.31 15 5.25 6.39 7.17 8.19 9.26 9.66 16 4.90 5.96 6.69 7.64 8.64 9.02 17 4.55 5.54 6.21 7.10 8.02 8.37 18 4.20 5.11 5.74 6.55 7.40 7.73 19 3.85 4.68 5.26 6.00 6.79 7.09 20 3.50 4.26 4.78 5.46 6.17 6.44 21 3.15 3.83 4.30 4.91 5.55 5.80 22 2.80 3.41 3.82 4.37 4.94 5.15 23 2.45 2.98 3.35 3.82 4.32 4.51 24 2.10 2.55 2.87 3.28 3.70 3.87 25 1.75 2.13 2.39 2.73 3.09 3.22 26 1.40 1.70 1.91 2.18 2.47 2.58 27 1.05 1.28 1.43 1.64 1.85 1.93 28 0.70 0.85 0.96 1.09 1.23 1.29 29 0.35 0.43 0.48 0.55 0.62 0.64 30 0.00 0.00 0.00 0.00 0.00 0.00 Page 10 ... G> 0.. Q) G> LI.. o-·-"O ..0 c: ::> 0 0 0 -G> G> (I) O> ... 0 .s::. 0 I/) 0 ... G> 0.. -G> G> LI.. o-·-"O ..0 c: ::> 0 0 0 -G> G> (I) O> ... 0 .s::. 0 I/) 0 14 .00 12 .00 10.00 8.00 6 .00 4.00 2 .00 0.00 18 .00 16 .00 14 .00 12 .00 10.00 8 .00 6 .0 0 4 .00 2.00 0 .00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 2-Year Storm Event 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph ---Tota l Post-Development Hydrograph 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event 5 10 15 20 25 Time (Minutes) ---Pre-Development Hydrograph ---Post-Development Outflow Hydrograph Without Detention Page 11 30 30 20.00 .. 18 .00 Cl> 0.. 16 .00 -Cl> Cl> 14 .00 u.. o -12 .00 ·-"O ..0 c :::7 0 10 .00 () 0 -Cl> 8 .00 Cl> (/) O> .. 6 .00 0 .s::. 0 4 .00 \/) a 2 .00 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Eve nt 5 10 15 20 25 Time (Minutes) 30 ---Pre-Development Hydrograph Post-Development Outflow Hydrograph Without Detention 25 .00 .. Cl> 0.. 20 .00 -Cl> Cl> u.. o-15.00 ·-"O ..0 c :::7 0 () 0 -Cl> 10 .00 Cl> (/) O> .. 0 .s::. 0 5 .00 \/) a 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 Page 12 25.00 .... Q) Q. 20.00 -Q) Q) u.. o-15.00 ·-1J ..0 c ::::> 0 u 0 -Q) 10 .00 Q) Cl) C> .... 0 .s:: ~ 5.00 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 Hydr ograph Without 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) ----Pre-Development Hydrograph ----Post-Development Outflow Hydrograph Without Detention Page 13 30 Detention Pond De th Vs. Volume Elevation Depth Volume (Feet) (Ft3) 296.25 0 .00 0 296 .76 0 .51 1,186 297 .00 0 .75 2,473 298 .00 1.75 8,603 298 .25 2.00 10,333 298.50 2.25 12 ,148 Detention Pond Depth Vs. Volume 2.50 2.00 1.50 ,... -Q) Q) u.. -.&:. -a. Q) a 1.00 0 .50 0.00 0 2,000 4,000 6 ,000 8 ,000 10,000 12,000 14,000 Detention Pond Volume (Cubic Feet) Page 14 Rating Curve For Outlet Control Structure Pipe Dia. (Inches): 12 1.00 Depth Vs. Volume Pipe Length 255.00 Feet Elevation Depth Discharge (Feet) Ft3/Sec 296.25 0.00 0.00 296.76 0 .51 1.46 297 .00 0.75 1.77 298.00 1.75 2.71 298 .25 2.00 2.89 298 .50 2 .25 3 .07 Rating Curve For Outlet Control Structure Depth Vs. Volume l.50 ....... -Q) Q) u.. ....... ~ -a. Q) 0 l.00 0.00 0 .50 l.00 1.50 2 .00 2.50 3 .00 3.50 Discharge (Cubic Feet Per Second) Page 15 I Storage Indication Curve 3.50 3.00 ~ 2.50 c 0 0 ~ £ -2.00 Q) Q) LL. 0 :0 ::::J ~ 1.50 Q) O> 0 ~ & 1.00 0.50 0 .00 Depth Storage Discharge 2s/t 2s/t+O (Fe et) (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0.00 0 0.00 0.00 0.00 0 .51 1,186 1.4 6 39 .53 41.00 0 .75 2 ,4 73 1.77 82.43 84 .21 1.75 8 ,603 2.71 286 .77 289.47 2.00 10 ,333 2.89 344.43 347.33 2.25 12 ,148 3 .07 404.93 408.00 Storage In di c atio n C urve --... v ~ / v / ~ / v l / f 0 .00 50 .00 100 .00 150.00 200.00 250 .00 300 .00 350 .00 400 .00 45 0.00 2s/t+O (Cubic Feet Per Second) Page 16 Inflow I Outflow Simulation 2-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 0.00 296.25 1 0.70 0 .70 0 .65 0 .70 0.02 0 .00 296.25 2 1.40 2 .10 2.56 2.75 0.10 0 .00 296.25 3 2.10 3.50 5.63 6.06 0 .22 0.01 296.26 4 2.80 4 .90 9.78 10.53 0.38 0 .03 296.28 5 3 .50 6.30 14.93 16.08 0.57 0 .08 296.33 6 4 .20 7 .70 21.02 22.64 0.81 0.16 296.41 7 4 .90 9 .10 27.98 30.13 1.07 0 .28 296.53 8 5 .60 10.51 35.74 38.48 1.37 0.45 296.70 9 6.30 11 .91 44 .63 47.65 1.51 0 .54 296.79 10 7 .00 13 .31 54.77 57 .93 1.58 0.60 296.85 11 6.65 13.66 65.10 68.42 1.66 0.66 296.91 12 6.30 12 .96 74 .60 78.06 1.73 0.71 296 .96 13 5.95 12 .26 83 .29 86.86 1.78 0.76 297 .01 14 5.60 11.56 91 .20 94.85 1.82 0.79 297.04 15 5.25 10.86 98 .35 102.06 1.85 0.82 297.07 16 4 .90 10.15 104.74 108.51 1.88 0 .85 297.10 17 4.55 9.45 110.38 114.20 1.91 0 .87 297.12 18 4 .20 8.75 115.27 119.13 1.93 0.89 297.14 19 3 .85 8 .05 119.42 123.32 1.95 0 .91 297.16 20 3 .50 7 .35 122 .84 126.77 1.97 0 .92 297 .17 21 3 .15 6.65 125.54 129.49 1.98 0 .93 297.18 22 2.80 5.95 127.51 131.49 1.99 0.94 297 .19 23 2.45 5 .25 128.78 132.77 1.99 0 .95 297 .20 24 2 .10 4 .55 129 .34 133.33 2.00 0.95 297.20 25 1.75 3 .85 129 .20 133.19 2 .00 0 .95 297 .20 26 1.40 3 .15 128.37 132.35 1.99 0.95 297 .20 27 1.05 2.45 126.85 130.82 1.98 0.94 297.19 28 0.70 1.75 124.65 128.60 1.97 0.93 297 .18 29 0 .35 1.05 121 .78 125.70 1.96 0 .92 297.17 30 0 .00 0 .35 118.24 122.13 1.95 0 .90 297.15 P age 17 Inflow/Outflow Simulation 2-Year Storm Event 14.00 12.00 10.00 -"C c: 0 0 Cl> (/) ... Cl> 8.00 0.. -Cl> Cl> u.. 0 :0 :J 6.00 0 -~ 0 E I :J 0 I 4 .00 I I I 2.00 0.00 0 ----Pre- Developme nt Hydrograph I I I I I • I I I I I I I I I I 5 I' I " " I " I " " " " ' " " .. " "' " " ' " ' " '\ ' I ' ' ' ' ' ' ' 10 15 20 Time (Minutes) Post- Developme nt Outflow Hydrograph Without Detention ----Post- Developme nt Outflow With Detention Page 18 ' " .. ' "' ' " ' " 25 30 -• -• -• Post- De velopme nt "Free- Flow· Inflow I Outflow Simulation 5-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 .00 296.25 0.85 0 .85 0.79 0 .85 0 .03 0 .00 296.25 2 1 .70 2 .55 3.11 3 .35 0 .12 0 .00 296.25 3 2.55 4 .26 6 .84 7 .37 0.26 0.02 296.27 4 3.41 5 .96 11 .89 12.80 0.46 0 .05 296.30 5 4 .26 7 .66 18.16 19.55 0 .70 0.12 296.37 6 5.11 9 .37 25 .56 27.53 0 .98 0 .23 296.48 7 5 .96 11.07 34.02 36 .63 1 .31 0.41 296.66 8 6 .81 12 .77 43 .79 46 .80 1 .50 0.54 296 .79 9 7 .66 14.48 55.09 58 .27 1 .59 0.60 296.85 10 8.52 16.18 67 .91 71 .27 1 .68 0 .67 296.92 11 8 .09 16.61 80.97 84 .52 1 .77 0 .75 297.00 12 7.66 15 .75 93.07 96.73 1.83 0 .80 297.05 13 7 .24 14.90 104.21 107.97 1 .88 0.84 297.09 14 6.81 14.05 114 .41 118 .26 1 .93 0.89 297.14 15 6 .39 13 .20 123 .66 127.60 1.97 0.93 297.18 16 5 .96 12.35 132.00 136.01 2.01 0.96 297.21 17 5 .54 11 .50 139.41 143.49 2 .04 1 .00 297.25 18 5 .11 10 .64 145 .91 150.05 2 .07 1.03 297.28 19 4 .68 9 .79 151 .50 155 .70 2 .10 1.05 297.30 20 4.26 8.94 156.21 160.44 2.12 1.07 297.32 21 3 .83 8.09 160 .02 164.30 2 .14 1.09 297.34 22 3.41 7 .24 162 .96 167.26 2 .15 1.10 297.35 23 2 .98 6 .39 165.02 169.34 2 .16 1.11 297.36 24 2 .55 5 .54 166.23 170.56 2 .17 1.12 297.37 25 2 .13 4 .68 166.58 170.91 2 .17 1.12 297 .37 26 1 .70 3 .83 166.08 170.41 2 .17 1.12 297.37 27 1 .28 2 .98 164 .74 169 .06 2 .16 1.11 297.36 28 0 .85 2.13 162 .57 166.87 2.15 1.10 297.35 29 0.43 1.28 159 .58 163.85 2 .14 1.09 297.34 30 0 .00 0.43 155 .77 160.00 2 .12 1.07 297.32 Page 19 Inflow /Outflow Simulation 5-Year Storm Event 18 .00 ., 16 .00 ' I ' I ' I ' 14 .00 • ' ' I ' I ' I ' ....... "O 12.00 c 0 0 I I\. I ' I ' Q) ' (/) I ' ... Q) ll.. 10.00 -Q) Q) ....... 0 :0 8 .00 :J () ..._, ~ 0 E 6.00 :J 0 4 .00 2.00 I "" ' . I ~ ' I ' I ' • ' II. /_../ ' ' "' ' I ' ~ ' .. ' I ' ' ' . ' -' ' I '' ' v . . ' ', """" -I . ' . ' ' ' /I , ~ ~ ', ' . '' ' ·!: · ... ,~ ' . ' . ' I I 1'. ' . I .. .., . v--' ' . '' . ' ' __/ ' ''' ' 0.00 0 5 10 15 20 25 30 Time (Min utes) Pre -----Po st -Post ------·-· Post - Develo pme Deve lo pme Deve lopme Deve lopme nt nt O utflow nt Outflow nt 'Fre e- Hydr o graph Hydr ograph With Flow ' With o ut Detention Dete ntion Page 20 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 .00 296.25 1 0 .96 0 .96 0 .89 0 .96 0.03 0.00 296.25 2 1.91 2.87 3.49 3 .76 0.13 0.00 296.25 3 2.87 4.78 7.68 8.27 0.29 0.02 296.27 4 3 .82 6.69 13.34 14.37 0.51 0.06 296.31 5 4.78 8.60 20 .38 21.95 0 .78 0 .15 296.40 6 5 .74 10.51 28.69 30 .90 1.10 0.29 296.54 7 6.69 12.43 38.19 41.12 1.46 0 .51 296.76 8 7.65 14.34 49.44 52.53 1.54 0 .57 296.82 9 8.60 16.25 62.41 65 .69 1.64 0 .64 296.89 10 9.56 18.16 77.08 80.57 1.75 0 .73 296.98 11 9 .08 18 .64 92 .07 95.72 1.82 0.80 297.05 12 8.60 17.68 105.97 109.75 1.89 0.85 297.10 13 8 .12 16.73 118.81 122.70 1.95 0.91 297 .16 14 7 .65 15.77 130.57 134.58 2 .00 0 .96 297.21 15 7 .17 14.82 141.29 145.39 2.05 1.00 297.25 16 6.69 13.86 150.95 155.15 2 .10 1.05 297.30 17 6.21 12 .90 159.59 163.86 2.14 1.09 297.34 18 5 .74 11 .95 167.19 171.54 2 .17 1.12 297.37 19 5 .26 10 .99 173.79 178.19 2.20 1.16 297.41 20 4.78 10 .04 179 .37 183.82 2.23 1.18 297.43 21 4 .30 9.08 183.95 188.45 2.25 1.21 297.46 22 3.82 8.12 187.55 192.08 2.26 1.22 297.47 23 3 .35 7 .17 190.17 194.72 2.28 1.24 297.49 24 2.87 6 .21 191 .81 196.38 2.28 1.24 297.49 25 2.39 5.26 192.50 197.07 2.29 1.25 297.50 26 1.91 4.30 192.23 196.80 2.29 1.25 297.50 27 1.43 3 .35 191.01 195.57 2.28 1.24 297.49 28 0 .96 2 .39 188.86 193.40 2 .27 1.23 297.48 29 0.48 1.43 185.79 190.30 2 .26 1.21 297.46 30 0 .00 0.48 181.79 186.26 2 .24 1.20 297.45 Page 21 In fl o w/O utf low Simula ti o n 10-Year Storm Event 20.00 j' 18.00 I ' I ' . ' 16.00 I ' I ' I ' I " ' -14.00 I "O c: 0 I ' , -0 Q) (f) 12.00 ... Q) 0.. -Q) Q) 10.00 LL. 0 :0 :J u ......, 8.00 3'; 0 E :J 0 6.00 4.00 I ' . .. I ' I I ~ "" ' I ' . ; .... ", ~ ' • , I ' I ' " ' ' ' • /./ ' ' ··.~ ' ' • ' ' ' ' I ' I ' I , ', " ~\ .··I . , ' ' . '.' . ' '·,,0 . // ' • • ' I '\.. ' . '' I ' ' . ~t .. , , v--', ' ' ~ •, ' ' ' 2.00 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 Page 22 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 0.00 296 .25 1 1.09 1.09 1.01 1.09 0 .04 0 .00 296.25 2 2.18 3.28 3 .98 4 .29 0.15 0 .01 296.26 3 3 .28 5.46 8.77 9.44 0 .34 0.03 296 .28 4 4 .37 7.64 15 .24 16.41 0.59 0 .08 296.33 5 5.46 9.83 23 .28 25.06 0.89 0.19 296.44 6 6.55 12.01 32 .77 35.29 1.26 0 .38 296.63 7 7.64 14.19 43 .95 46.96 1.50 0.54 296.79 8 8.73 16.38 57 .13 60.33 1.60 0 .61 296 .86 9 9.83 18.56 72 .26 75.68 1.71 0 .70 296 .95 10 10.92 20 .74 89 .38 93.00 1.81 0 .78 297.03 11 10 .37 21.29 106.88 110.67 1.89 0 .86 297.11 12 9 .83 20.20 123.14 127.07 1.97 0.92 297.17 13 9 .28 19 .10 138.17 142.24 2.04 0.99 297 .24 14 8 .73 18.01 151.98 156.18 2 .10 1.05 297.30 15 8.19 16.92 164.59 168.90 2.16 1.11 297 .36 16 7 .64 15 .83 175.99 180.41 2.21 1.17 297.42 17 7.10 14.74 186.21 190.73 2.26 1.22 297.47 18 6 .55 13 .65 195.26 199 .86 2 .30 1.26 297 .51 19 6.00 12.55 203 .14 207.82 2.34 1.30 297.55 20 5.46 11.46 209 .87 214 .61 2 .3 7 1.34 297 .59 21 4 .91 10.37 215.46 220.24 2.39 1.37 297 .62 22 4 .37 9 .28 219 .91 224 .74 2.41 1.39 297.64 23 3 .82 8.19 223 .25 228 .10 2.43 1.41 297 .66 24 3.28 7 .10 225.46 230 .34 2.44 1.42 297.67 25 2.73 6.00 226 .58 231.47 2.44 1.43 297.68 26 2.18 4 .91 226 .61 231.49 2.44 1.43 297.68 27 1.64 3 .82 225 .55 230.43 2.44 1.42 297.67 28 1.09 2.73 223.42 228.28 2.43 1.41 297.66 29 0 .55 1.64 220.23 225.0 6 2 .41 1.39 297.64 30 0 .00 0 .55 215.99 220.78 2 .39 1.37 297 .62 P a ge 23 Inflow/Outflow Simulation 25-Year Storm Event 25 .00 I ' 20 .00 " I ' ' I ' I ' -I ' 1J c I ' 0 I ' 0 I Q) C/) 15 .00 ' ... ' Q) I ' Q. -I ' Q) I ' Q) LL. I ' 0 ' :0 I ' :::J () ' -10 .00 ~ I ' ' . 0 I ' ' 5: • ' ' :::J ' ' ' 0 I . ' ' I . ' ' . ' . ' I ' ' I 5 .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 O utflow nt "Free- Hydrograph Hydrograph Wit h Flow· With out Dete ntion Detention P age 24 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 0.00 296.25 1 1.23 1.23 1.15 1.23 0.04 0.00 296 .25 2 2.47 3.70 4.50 4.85 0.17 0.01 296.26 3 3.70 6.17 9.91 10.67 0 .38 0.03 296.28 4 4.94 8.64 17.23 18.55 0.66 0.10 296.35 5 6.17 11.11 26.31 28 .33 1.01 0 .24 296.49 6 7.40 13.57 37.04 39.89 1.42 0.48 296 .73 7 8.64 16.04 49 .99 53 .09 1.55 0 .57 296.82 8 9 .87 18.51 65 .18 68.50 1.66 0.66 296.91 9 11.11 20 .98 82.60 86.16 1.78 0.76 297.01 10 12 .34 23.45 102.30 106.04 1.87 0.84 297 .09 11 11 .72 24 .06 122.43 126.36 1.96 0 .92 297.17 12 11 .11 22.83 141 .16 145.26 2 .05 1.00 297.25 13 10.49 21.60 158.50 162 .76 2.13 1.08 297 .33 14 9 .87 20.36 174.45 178.86 2 .20 1.16 297.41 15 9.26 19 .13 189.04 193.58 2 .27 1.23 297.48 16 8 .64 17.89 202 .27 206 .93 2.33 1.30 297.55 17 8.02 16.66 214 .15 218 .93 2 .39 1.36 297.61 18 7.40 15.43 224 .71 229 .58 2.43 1.42 297.67 19 6.79 14.19 233 .95 238.90 2.48 1.46 297.71 20 6.17 12.96 241 .88 246.91 2.51 1.51 297 .76 21 5 .55 11.72 248 .51 253 .60 2 .54 1.55 297 .80 22 4 .94 10.49 253 .86 259 .00 2.57 1.58 297.83 23 4.32 9 .26 257.94 263.12 2.59 1.60 297.85 24 3.70 8.02 260 .76 265 .97 2.60 1.61 297 .86 25 3 .09 6.79 262 .34 267.55 2.61 1.62 297.87 26 2.47 5.55 262.67 267 .89 2.61 1.63 297.88 27 1.85 4.32 261 .78 266.99 2.61 1.62 297.87 28 1.23 3 .09 259 .67 264.87 2.60 1.61 297.86 29 0 .62 1.85 256.36 261.53 2.58 1.59 297.84 30 0 .00 0.62 251 .86 256.98 2.56 1.56 297.81 Page 25 Inflow/Outflow Simulation 50-Year Storm Event 25 .00 I ' I ' I ' .. I ' I .. 20 .00 I I ' ' I I ' ...... "O I ' c I ' 0 0 I ' Cl) ' <I) 15.00 -Cl) ll.. -Cl) Cl) LL. 0 :.a ::::J u -10 .00 ~ 0 ~ ::::J 0 5.00 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 Page 26 Inflow I Outflow Simulation 100-Y ear 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 .00 296 .25 1 1.29 1.29 1.20 1.29 0 .05 0 .00 296 .25 2 2 .58 3 .87 4.70 5.06 0.18 0.01 296 .26 3 3.87 6.44 10 .35 11 .14 0.40 0.04 296.29 4 5.15 9.02 17.99 19 .37 0.69 0.11 296 .36 5 6.44 11 .60 27.47 29 .58 1.05 0.27 296 .52 6 7.73 14.17 38 .71 41.65 1.47 0.51 296.76 7 9.02 16.75 52.33 55.46 1.57 0 .59 296 .84 8 10.31 19 .33 68.29 71.66 1.68 0.68 296 .93 9 11.60 21 .90 86.60 90.20 1.80 0 .77 297 .02 10 12 .88 24.48 107.29 111.08 1.89 0.86 297 .11 11 12 .24 25 .12 128.43 132.41 1.99 0.95 297.20 12 11 .60 23 .84 148.10 152.27 2.08 1.04 297.29 13 10.95 22.55 166.32 170.65 2 .17 1.12 297.37 14 10.31 21 .26 183.09 187.58 2 .24 1.20 297.45 15 9 .66 19.97 198.43 203 .06 2.31 1.28 297.53 16 9 .02 18.68 212 .36 217.11 2 .38 1.35 297.60 17 8.37 17.39 224.88 229.75 2.44 1.42 297.67 18 7 .73 16.11 236 .01 240.99 2.49 1.48 297.73 19 7 .09 14.82 245 .77 250 .83 2.53 1.53 297.78 20 6.44 13 .53 254 .16 259 .30 2.57 1.58 297.83 21 5 .80 12 .24 261 .19 266.40 2.60 1.62 297.87 22 5.15 10 .95 266 .89 272 .14 2.63 1.65 297.90 23 4 .51 9 .66 271 .25 276 .55 2.65 1.67 297 .92 24 3.87 8.37 274 .30 279 .63 2.66 1.69 297.94 25 3 .22 7 .09 276.05 281 .39 2.67 1.70 297.95 26 2 .58 5 .80 276.50 281 .84 2.67 1.71 297.96 27 1.93 4.51 275 .67 281 .01 2.67 1.70 297.95 28 1.29 3.22 273 .57 278.89 2.66 1.69 297.94 29 0 .64 1.93 270 .22 275 .51 2.64 1.67 297.92 30 0.00 0 .64 265.62 270.86 2.62 1.64 297 .89 P a ge 27 30.00 25.00 u c 20.00 0 0 CJ) en ~ 0.. -CJ) CJ) I.&-15 .00 0 :0 :::7 u -~ 0 =§ 10 .00 0 5 .00 0 .00 Inflow/Outflow Simulation 100-Yeor Storm Event I I I I I I I 0 5 Pre----- Developme nt Hydrog raph I I ' I ' 10 ' ' ' ' ' ' ' 15 20 Time (Minutes) Post-Post- Developme Developme nt Outflow nt Outflow Hydrograph With Without Detention Detention Page 28 25 30 ......... Post- Developme nt "Free- Flow" Inflow/Outflow Simulation 2-Year Storm Event 9.00 8.00 7.00 £;' 6.00 c: 0 0 Q) Ch ~ Q) 5.00 Q.. -Q) Q) ~ 0 :.0 4.00 j (.) -~ 0 s: j 0 3.00 2.00 l.00 0 .00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ---•Total Post-Development Hydrograph P age 29 Inflow/Outflow Simulation 5-Year Storm Event 12 .00 10 .00 ,.... 8 .00 "O c 0 0 Q) (/) ... Q) Q. -Q) Q) 6.00 u.. 0 :0 :I () ....., 3'; 0 E :I 0 4 .00 2 .00 0 .00 0 5 10 15 20 25 30 Time (Minutes) ----Pre-Development Hydrogra ph ----Total Post-Develo pment Hyd rograph P age 30 Inflow/Outflow Simulation 10-Year Storm Event 12.00 10 .00 ....... 8 .00 "O c 0 0 Q) Cl) ... Q) c.. -Q) Q) 6.00 u.. 0 :0 :J (.) ....., ~ 0 :;: :J 0 4 .00 2.00 0.00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ----Total Post-Development Hydrograph Page 31 Inflow/Outflow Simulation 25-Year Storm Event 14 .00 12 .00 10.00 -1J c 0 0 G> Cl) ... 8.00 G> 0.. -G> G> LL. 0 1i ::::J 0 6.00 -~ 0 E ::::J 0 4 .00 2 .00 0 .00 0 5 10 15 20 25 30 nme (Minutes) Pre-Development Hydrograph ----Total Post -Dev elopment Hydrograph Page 32 Inflow/Outflow Simulation 50-Year Storm Event 16 .00 14 .00 12 .00 ....... 'U c 0 10 .00 0 Q) (/) ... Q) Q. -Q) Q) 8 .00 u... 0 :.0 j u -~ 0 6 .00 ~ j 0 4.00 2 .00 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre -Development Hydrograph ----Total Post-Develo pment Hydrograph Page 33 Inflow/Outflow Simulation 100-Year Storm Event 16 .00 14.00 12.00 ....... 1J c 0 10.00 0 Cl> (/) ... Cl> 0.. -Cl> Cl> 8.00 u.. 0 :0 j () -~ 0 6.00 :E j 0 4 .00 2.00 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Post-Development Hydr ograph Page 34 Detention Pond Storage Volumes as Percent of Maximum Volume 100% 90% 80% 70% Q) E j 0 60% > E j E ')( 50% 0 :::? 0 -40% c Q) 0 .... Q) Q.. 30% 20% 10% 0% 2-year 5-year 10-year 25-year 50-year 100-year Design Storm Storm Simulation Synopsis 2-ear 5-ear 10-ear 25-ear 50-ear 100-ear Storm Depth 0 .95 1.12 1.25 1.43 1.63 1.71 Storm Elevation 297.20 297 .37 297 .50 297.68 297.88 297 .96 Storm Volume 3707 4750 5527 6612 7838 8329 Maximum Capacity 12148 12148 12148 12148 12148 12148 Percent of Capacity 31% 39% 45% 54% 65% 69% Page 35 DEVELOPMENT PERMIT PERMIT NO . 315A Neatherlin Storage FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA RE : CHAPTER 13 OF THE COLLEGE STATION CITY CODE SITE LEGAL DESCRIPTION: Volume 1552 Page 40 , Abstract 54 Robert Stevenson League SITE ADDRESS: 4004 South Texas Avenue OWNER: Kenneth Neatherlin P .O . Box 3321 Bryan, Texas 77805 DRAINAGE BASIN: South Fork of Lick Creek, Channel Reach IV TYPE OF DEVELOPMENT: This permit is valid for placement of fill material on site to be used for site construction . All fill material shall be placed such that it does not migrate off-site . Appropriate silt fencing shall be used to prevent silt and debris from leaving the site . Contractor shall prevent silt and debris from leaving the site in accordance with the City of College Station Drainage Policy and Design Criteria . Owner and/or contractor shall be responsible for any damage to existing city streets or infrastructure due to heavy machinery and/or equipment. 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 of an area outside the special flood hazard area. All development shall be in accordance with the plans and specifications s mitted to and approved by the City Engineer in the development permit application for t above named project and all of the codes and ordinances of the City of College Station t t apply. Date I I /-;r) 0 -Cf(, Date Date 1-_Jo-re- DEVELOPMENT PERMIT PERMIT NO . 315 Neatherlin Storage FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA RE : CHAPTER 13 OF THE COLLEGE STATION CITY CODE SITE LEGAL DESCRIPTION: Volume 1552 Page 40, Abstract 54 Robert Stevenson League SITE ADDRESS: 4004 South Texas Avenue OWNER: Kenneth Neatherlin P.O . Box 3321 Bryan, Texas 77805 DRAINAGE BASIN: South Fork of Lick Creek, Channel Reach IV TYPE OF DEVELOPMENT: This permit is valid for site construction associated with this project, including fire hydrant installation, fire lane designation , landscaping, and grading, according to the approved plans . Contractor shall prevent silt and debris from leaving the site in accordance with the City of College Station Drainage Policy and Design Criteria. Owner and/or contractor shall be responsible for any damage to existing city streets or infrastructure due to heavy machinery and/or equipment. 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 of an area outside the special flood hazard area . All development shall be in accordance with the plans and specifications submitted to and approved by the City Engineer in the development permit application for the above named project and all of the codes and ordinances of the City of College Station that apply . <:}~~ Administrator/Representative DatJ ' 11 /tt /ars /' Scale: ff, GENERAL NOTES: l.} ALL CONSTRUCTION. SHALL BE IN A CITY OF COu.EGE STATION STAND~ SPECIFICATIONS. 2 .) IT SHALL BE THE RESPONSIBILITY TO VERIFY .nm EXACT DEPTH AND EXISTING UJmERGROUlm UTILITY I PROJECT AREA PRIOR· TO COMMEN1 BENCHMARK; A RAILROAD SPIKE IN A TELEPHONE P< 34:5.00 FEET ALONG NORTH PROPERTY CORNER OF SAID TRACT, AND THEN AF SOUTHEAST THROUGH THE PROPERTY ELEVATION • 300.00 FT. j//C/Nl"TY H4P . . . ~ .-~ ~ . . .• f for .~---A ·-NEATJIERLIN SELF . ·. ,\ . . STORAGE 4004 South Texas Avenue College Station, Brazos County, Texas • Scale: 1 " = 30' Septe~ber , 1995 . . . GARRETT ENGINEERING ~I I .'1'1 ' ' r . ' .' . -·-·----_____ ___. ,.. S tlt.e Department of HighwaYl rand Public Transportation Form I0'.58-Rcv. 12-86 Permit to Construct Acces s Driveway Facilities on Highway Ri ght of Way To: !J\ e.. 1< E.N "-1 LI 8 t-H::.. A TH £...~LI N Hwy.~. All£.. Permit No: __ _ y.o . e-.ox -?->3?__,\ Control Section ~ N.~Tl-\E\2..LI N ~ELF S.\OR.A.~E. C..01--\. PLE..)<. AT 4004 ~U..T\-\ \"£.)(...AS. A"'-J'E.N 1...1. E. The State Department of Highways and Public Transportation, hereinafter called the State, hereby authorizes ~-· __ _ ~E.NNC.TH Ns:A T~ Ctz... UN , hereinafter called the grantee, to (re) construct an access drivew a y on the highw ay ri ght of way abutting highway no. m Bg 6-z__()~ County , located __,1_1--1-'--------- c_p U-1C...GS::. '";:,TA.T\ON " TE:..)(.P..S, Subj ect to the follo wi ng : 1. 2. The grantee is responsible for all costs associated with the construction of this access driveway . Design of facilities shall be as follows and/or as shown on sketch: C AI C ULATION 'S A !U: I NC UJ,,OEO CAP6C IT'-1 \J sR-1 Flc.ATI o".1 All construction and materials shall be subject to inspection and approval by the State. 3. Maintenance of facilities constructed hereunder shall be the responsibility of the grantee, and the State reserves the rig ht to require any changes, maintenance or repairs as may be necessary t o provide protection of life or property on or adja- cent to the highway. Changes in design will be made only with approval of the State. r12J101 IT -· I NCl..UE'll"6 l.VL.vEJLT WkS IH'r~ ".If t)Ct70'f UNt7~ rJrl.1 Vt;W*t -- 1 /2~ /<it,. ?u T>c WT f0£ OISCftAfZ61 rJ6 THE v-r 1 L1 !.'f rEJZ.n rr ~'lEN1" 1QtJ -('0110 FLP w5 I ~ l/N ~ SEf AJLAfE ------------ - INTo (,~~. ~ orr~ Figure XII Application Form Development Permit lnsid ~tablished Flood Hazard Areas City of College Station, Texas (re: Ordinance No. 1728) Site Legal Description: ,.__}e_Q,t, tbv I \V\ Se.).£ -S\-Ova..<t{= eovnp\.u. Site Address: Lj CD Lj SJ. &#v T..f\[Ct.$ t;..,vwuu l C'o\ \i_~,< "$~\j'ayJ l e::iycqps, C o UM 4J 1 T~ Owner: MV . i,£ vWH' XV\, i-J.g.sµ.,\Jh.n-\\n Address: (l .o. 6::2 i Z,'P ':L \ Telephone No.: (Y.cB .) :iJ 'B-=iL.oLA3 Architect/ Address: YYL.1 4 (_ay\<.,v C~<J:· :;>t...u'k \o?D Engineer: __...C .... :i ... o.. ..... v...._V<,_±t~_.~=----\(\_._,u~I.....,,' VU-""'-{ .... )Cl/:.i...i..Y\,_._,,~---------Telephone No.: i.W ca ) 6 y h!. -:l.,.lp ~ 6 Contractor: Address: ------------------~ ------------Telephone No.:---------- Date Application Filed: Nov-'.m\aeK 2.2.\ Lq,q i:; Approved:----------- Application is hereby made for the following specific waterway alterations:------------ °' cle kM \-km Qood. >P 1' l \ ru c DYl s.\-u d -t d hl c .D Y) \yo\ (\).VJ Q t g S:vavvi Ht=&--' Attached as part of this application: ~Application Fee ra"~igned Certificate g/Site and Construction Plans, with supporting documentation: two (2) copies of each o..\w...~ s.u..~f-\-'kd. O Other: -----------------~ ACKNOWLEDGEMENTS: I, K,.e,~ rv ; as Vhw \;v h-, as owner, hereby acknowledge or affirm that: The above Drainage Plan and supporting documents complies wiht the requirements of Ordinance No. 1728, :~ .?~ Date Date Date Figure XIl Continued 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 bas~~' evation established in the latest Federal Insurance Administration ........ ,, Flo azard .: ... ~. . . . ··.. ~ 1 s amended. ; 0/ ·1\S\ ,,. ,--- '*/ ~ //--Y7--'"7J ~~~~~~~~~~~~~~~~- Date Date I 1.')~ !! .... £\cud cf 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 fac ilities . 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 . r--....-i10.9J D£LtV~ To {)J lT H !><'LL i (9o/C1tR fl 17~ -round IVV• eMl vtll &V&' .:ii ai1t1. PROJECT REVIEW COMMITTEE REPORT TO : Kenneth Neatherlin, Neatherlin Self-Storage P . 0 . Box 3321, Bryan, TX 77805 FROM: SUBJECT: Fred Patterson, Patterson Architects 2402 Broadmoor Drive, Suite A201, Bryan, TX 77802 Don Garrett, Garrett Engineering 4444 Carter Creek Parkway, Suite 108, Bryan, TX 77802 Project Review Committee (J ~ Sabine Kuenzel, Senior Planner ~ Kent Laza, City Engineer Charles Smith, P & Z Represent t1ve Others Attending Natalie Thomas, Planning Technician Tony Michalsky, Electrical Operations Coordinator Parking Lot Plan -A-Neatherlin Self Storage; proposed facility to be located at 4004 South Texas Avenue, along the west side of State Highway 6 north of the Barron Road intersection . (95-406) A Project Review Committee Meeting was held Wednesday, October 11, 1995 to discuss the above mentioned parking lot plan . City Engineer Laza moved to recommend approval of the parking lot plan with the following conditions : CONDITIONS OF APPROVAL: Ordinance Requirements: Landscape Plan Related: Provide an irrigation system plan for the new landscaping areas (existing tree area is exempt.) Provide one more Streetscape tree in the reserve area (total required is 14). The phase line must be shown 20' from all site elements. General note #1 refers to the removal of any existing trees that will interfere with construction . The trees located within the 24' reserve area CANNOT be removed . Add a general note to address this requirement or note on the landscape plan that a complete survey of all trees are shown. PR C R eport A -Nea th erlin Storage Case #95-406 Page 2 of 3 CONDITIONS OF APPROVAL (cont.): Ordinance Requirements (cont.): Site Plan Related: tf./17 Provide aesthetic details of the proposed detention wall . -Show the development phase line 20' from the developed area includin g site elements . O~"&] Delineate where the fire lane is to be marked . #/ Provide detail to scale showing the fence and fire hydrant l?lacement in t~e isl_a:id . (Staff is (~tied) concerned it may not fit and the island may need to be wider.) A pubhc ut1hty easement lJ~il will be required for the proposed fire hydrant. ~ ~· Locate the boundaries of the retail sales display area . - General note #6 should be changed to include that "all areas not located within the development to be restored to original condition". Non-Site Plan Related: A permit from the Texas Department of Transportation must be obtained prior to any work in the right-of-way . The existing gravel road will be addressed with the next ha of this development to determine the right-of-way width and possibility of extendmg it through to Longmire . At a minimum, the driveway at its existing width must meet the City's paved driving and curbing standards . '.>m ments/Concerns : Staff is concerned with the turning radius of the drive between the longest storage building and the office building. Staff would recommend that the fence not be installed in this area until such time that a fire truck can come out to the site to see if that maneuver can be made without damaging the fence . There is also the need to stripe the ends of the building as "no parking" to allow emergency vehicle access . Coordinate details with Assistant City Engineer Morgan at (409) 764-3570. Provide a 20' public utility easement to cover the existing overhead electrical lines that run parallel to the existing gravel road . The customer will be responsible for 20% of the total cost of electrical service. Coordinate service details with Operations Coordinator Tony \M ichalsky at ( 409) 764-3660 . ~oord i nate telephone service details with G .T .E . Representative Laverne Akin at (409) 21-4723 . I \ ,___~0_21_2_21_9_5~1_3_:o_5~-'8'~40_9_7_6_4_3_4_96~~~~D~E~VE=L~OP~ME=N~T~S~V~CS::._~~~~~~~~~~~00~1~ '.1 ii ~I II •i :1 ii !i ii ii !I II I I TRAN SMISSIO N OK TX/RX NO. CO NN ECTIO N TEL CO NNECTIO N ID START TIME USAGE TIME PAGES RES ULT *************************** *** ACTI VI TY REPOR T *** *************************** 1145 97765004 02 1 22 13 :03 01 '51 2 OK /YP!Cd.L t:'b€C7/VN - \\\;;-~ .i{~ /\)~"; ~,-1 ~ /\I.TC:?. "~-~-~-~· ~-~ .~. ~-~. ~-~. ~-~.,. •/·I ·/ ·I· I •/·/•/•/· I ·I ·I· I ·I · I · I· I .... ,., ..... , ..... ,.,., ..... , ..... ,.,.,.,.,.,.,. ·I· l •l •/· l·l ·I· I ·I •/ ·I • I •/• I · I ·/• I •/· I • I ·I . '.' ., . '"\ .. , . '""" '., ., . ' ..... '.'. ,. '.,. , ..... '.'. I· I ·I · I ·/ •I • I •I· I ·.!· I· I ·I · I · I ·I · I •I· l•l ·I ·I ·I · I· I \·\·\·\·\•\•\•\·\·\•\·\•\•'\•'\•\•\.•\•\•\•\·\·\·\•\•\• ·I· I ·!• /·I ·I · I•/• I •I • I ·! •I• I· I ·I• I •I •/•/•/· I •I • I •I ·I • I f:i'.i;IWit ititimmmIWJ;JiitJHH~Hi~f ;HI;I~HIH~~~'.-.. DEVELOPMENT SERVICES ffOf TE X AS AVE COLLEGE STATION. TEXAS 77840 Facsimile Cover Sheet To: Company: Phone: Fax: From: Company: Phone: Fax: Date: Pages including this cover page: (409) 764-3570 C409) 764 -3496 fAX ¥* ., .. ,.,. ,. ,., .,.,., ., .. ,. ,. ,. ,., . ·/•/·I · I ·/ ·I •/ ·I · I ·I · I · I •/ •I ·I ·I· . ,., ., . ,., .,. ,., . ,., . \. ,., . ,. '. '. ,., . ' •I •I ·I· J ·I • /·I •/• I •I • I •/• I• I ·I • I ·I· I • I·/· . '·\ •\ •\.•\.. \•\. •\. \•\. \•\ •\. ,., .. \•\ •\· '•\. \•\ •\ •I •I• I ·I ·I ·/ •I • J •J •I ·/•/•/•/ •I • I •I • l ·I · I · I ·I · I •/• . '.,. ,., . ,., ., . ,., . ,. '•\. ,. '.,. ,., . ,. '•\.' ., . ,. '.,.,. •I· I •I •I • I ·I · I · I •/ •I •I •/• I •I •/•/· /•I · I · I · I · I• I · I · I•/• I . '. ,. '·\.. \·'. ,. \ ., . ,. '. \• \ ·\.. ,. '.,. ,., . '. '.,. ,., . \• \ •\• ,. •I· I ·I· I · I •I · /•I· I· J ·I • I •I • I • I · I • I •I• I · I • I • I ·I · I • I ·I• I ·/• I '. ,., . ,. '. \. '•\.'.' ., . ,., .,. '.,. ,., ., . '.'. ,. '.'. '.'. ,. '. ,. '. •/•I •I • I ·I · I · I · I · I•/• I • I •I • I ·I · /-.1 •/•I ·I · I · I · I· I •I • I · I ·I · I ·I · I .,.,., ., ., . '. ,. '. ,., .,. '.,. ,., . '. ,., . \•' ., . ,. '. ,. '. ,. '.,. ,., ., . \.. DRAINAGE COMPUTATIONS for NEATHERLIN SELF STORAGE COMPLEX 4004 South Texas A venue Prevared for Kenneth Neatherlin P.O . Box 3321 Bryan, Texas 77805 Telephone: (409) 778-4663 Prepared by .· Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 * September 1995 * ,P::_e v1 «;tel Ocf-ober-{°t75 DRAINAGE COMPUTATIONS for NEATHERLIN SELF STORAGE COMPLEX 4004 South Texas A venue College Station, Brazos County, Texas Prenared fo r Kenneth Neatherlin P.O. Box 3321 Bryan , Texas 77805 Telephone : ( 409) 778 -4663 * September 1995 * f-c v OI ud-- DRAINAGE COMPUTATIONS for NEATHERLINSELFSTORAGECOMPLEX 4004 South Texas A venue College Station, Brazos County, Texas 1995 * The project is situated at 4004 South Texas Avenue in southern College Station and the storage complex is to be established within the bounds of 3.33 acre tract The total drainage area tributary to the project is 3.33 acres. The pre-development run-off coefficient was estimated to be 0.40. Assuming a worst case scenario, the entire developed area was considered to be impervious with a post-development run-off coefficient of 0.90 in determining the drainage calculations . A detention facility will be constructed in the southwestern portion of the property in keeping with the existing contours and optimal flow patterns. 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 . In this case, the detention pond will collect, store and meter run-off from 0.99 acres, the developed area of the project site . Since all generated runoff from the developed surface area will be routed through the pond, "free-flow" will consist of the remaining 2.34 acres of the site with a runoff coefficient of 0.50, comparable to the original pre-development value of 0.40. This value was chosen to account for the influence of the temporary buildings on the northern part of the property. These buildings will4'ffect the runoff behavior somewhat but will not create the nearly impermeable conditions associated with permanent structures. The temporary buildings will be up on blocks and allow runoff flow and infiltration beneath them. Essentially the only drainage effect of the temporary buildings is in concentrating runoff around each building's perimeter, but this water will be dissipated upon reaching the ground and follow natural surface flow patterns. These report calculations are summarized according to the following methodology. Beginning on page 3, based on the total tributary drainage area of the project (3.33 acres), the pre-development run-off coefficient (assumed 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. Computations on page 4 are based on the tributary area of 3.33 acres, the post-development run-off coefficient of 0.90, a minimum time of concentration of 10 minutes, to yield the relative pre-development peak discharge rate ("Q"). 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 . The "C" variable is the run-off coefficient (In the post- development condition "C" is assumed to be 0.90 . Generally, the post-development coefficient is weighted according to the relative amounts of pervious and impervious surface area. However, in this case, the total amount of surface area is taken as impervious.) "I" represents the rainfall intensity in inches per hour, and similarly "A" is the area of the basin in acres. Comparison of the peak pre-development discharge rate to the post-development discharge rate is included in the report to aid the designer in establishing a preliminary "target" of detention volume required. This preliminary estimate is determined as the volume difference generated between the pre-development and post- development hydrographs. (See pages 11-13 for pre-development and post-development hydro graphs.) Please note that the post-development hydrograph shown on these same graphs assumes no detention at all, therefore reflecting the scenario that there is no lag in runoff discharge and all water is allowed to "free-flow" unrestricted off the property . Page 1 Pages 5 and 6, respectively, provide information concerning the post-development run-off that is not routed through the detention facility, "free flow", and the post-development run-off that is routed through the detention facility and retained on site. computations performed on pages 3 & 4. The post-development hydrograph assumes no detention to facilitate direct comparison in the pre-and post-development conditions . Pages 9 & 10 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 6 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 10 is 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 to the relative 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 14 presents a data tabulation and a depth versus volume graph of the detention facility. Page 15 supplies a tabulation and a rating curve for the proposed outlet control structure. A circular pipe culvert was chosen due to the discharge ratio characteristics associated with the anticipated headwater depth. The pipe diameter of 8 inches (0.67 ft) was selected . This value was determined from the following equation for headwater depth (in feet), H = [ [ ( 2.5204 ( 1 + K)) I D4 ] + [ ( 466.18 n 2 L ( 1 + K)) I Dl6/3]] x (DI 10 )2 . "K" is the entrance loss coefficient ( K = 0 .50 for this case). "D" is the diameter of the pipe in feet. "L" is the length of culvert in feet. "Q" is the design discharge rate in cubic feet per second. "n" is manning's roughness coefficient (n = 0 .013 for concrete pipe), and "H" is the headwater depth in feet. Page 16 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 14 is a graphical solution to the equation presented in the "Drainaie Policy And Desiin Standards" as follows: 2s 1 (11+12) + (----------------01) = dt 2s2 (-----------------+ Oi) dt Page 17 through page 28 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 in the table and is the time at during which this maximum depth occurs from the onset 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 can be found in the table. The second page of each storm simulation represents the pre-development hydrograph, the post-development hydro graph (with no detention), the post-development hydrograph as routed through the detention pond, and post-development "free-flow" hydrograph for each storm event. Page 29 through page 34 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 seen from these same hydrographs that the post- development peak discharge rates have been slightly decreased in comparison to the 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 both the detention pond outlet control structure and project site are controlled to be less than the pre-development peak discharge rates with the use of the proposed Page2 detention facilities. Subsequent peak post-development discharge velocities are projected to be within manageable limits. Page3 Determine Total Pre-Development Peak Storm Water Discharge Rates Tributary Area ("A"): 3.33 Acres Pervious Area : 3.33 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: 6.33 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: 8.43 5-Year: 10.25 10-Year: 11 .50 25-Year: 13.14 50-Year: 14.85 100-Year: 15 .50 P age 3 c = 0.40 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 Determine Post-development Peak Storm Water Dischar e No Detention Tributary Area ("A"): 3 .33 Acres Pervious Area : 2.34 Acres Impervious Area : 0.99 Acres Run-Off Coefficient ("Cwt "): 0.62 Time Of Concentration ("T/c"): 1 O Minutes (Min) Hourly Intens ity 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 = 0.50 C = 0.90 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Peak Discharge Rate ("Q "): 2-Year: 13 .04 Cubic Feet I Second 5-Year : 15 .85 Cubic Feet I Second 10-Year: 17 .80 Cubic Feet I Second 25-Year: 20.32 Cubic Feet I Second 50-Year: 22 .98 Cubic Feet I Second 100-Year : 23 .99 Cubic Feet I Second Compa rison Of Pred evelopment And Post-deve lo ment Peak Dis char e Rates Predevelopment Post-Development Increase 2-Year: 8.43 Ft3 /sec 13 .04 Ft3/sec 4 .61 Ft3/sec 5-Year: 10.25 Ft3/sec 15.85 Ft3/sec 5.61 Ft3/sec 10-Year: 11 .50 Ft3/sec 17.80 Ft3/sec 6.29 Ft3/sec 25 -Year: 13 .14 Ft3/sec 20.32 Ft3/sec 7 .19 Ft3/sec 50-Year: 14 .85 Ft3/sec 22 .98 Ft3/sec 8.13 Ft3/sec 100-Year: 15 .50 Ft3/sec 23 .99 Ft3/sec 8.48 Ft3/sec Preliminary Deter mination Of Detention Pond Volume 2-Year : 4.61 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 4 ,151 Cubic 5-Year: 5.61 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 5,047 Cubic 10 -Year : 6.29 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 5,665 Cubic 25-Year : 7.19 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 6,470 Cubic 50 -Year : 8.13 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 7,314 Cubic 100-Year: 8.48 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 7,636 Cubic P a g e4 Feet Feet Feet Feet Feet Feet Determine Post-Development "Free-Flow" Peak Storm Water Discharge Tributary Area ("A"): 2.34 Acres Pervious Area: 2.34 Acres Impervious Area: 0.00 Acres Run-Off Coefficient ("Cwt"): 0 .50 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: 7.40 5-Year: 9.00 10-Year: 10 .10 25-Year: 11.54 50-Year: 13.04 100-Year: 13.62 Page5 C= 0.50 C= 0 .90 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"): 0.99 Acres Pervious Area : 0.00 Acres Impervious Area : 0 .99 Acres Run-Off Coefficient ("Cwt"): 0.90 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: 5.64 5-Year: 6.85 10-Year: 7.69 25-Year: 8.79 50-Year: 9.93 100-Year: 10.37 Page 6 c = 0.40 C= 0 .90 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 0.84 1.02 1.15 1.31 1.48 1.55 2 1.69 2.05 2.30 2.63 2.97 3.10 3 2.53 3.07 3.45 3.94 4.45 4.65 4 3.37 4.10 4.60 5.25 5.94 6.20 5 4.21 5.12 5.75 6.57 7.42 7.75 6 5.06 6.15 6.90 7.88 8.91 9.30 7 5.90 7.17 8.05 9.19 10.39 10.85 8 6.74 8.20 9.20 10.51 11.88 12.40 9 7.58 9.22 10.35 11.82 13.36 13.95 Peak=> I 10 8.43 f0.25 11.50 13.14 14.85 15.50 11 8.01 9.73 10.93 12.48 14.11 14.73 12 7.58 9.22 10.35 11.82 13.36 13.95 13 7.16 8.71 9.78 11.17 12.62 13.18 14 6.74 8.20 9.20 10.51 11.88 12.40 15 6.32 7.69 8.63 9.85 11.14 11.63 16 5.90 7.17 8.05 9.19 10.39 10.85 17 5.48 6.66 7.48 8.54 9.65 10.08 18 5.06 6.15 6.90 7.88 8.91 9.30 19 4.63 5.64 6.33 7.22 8.17 8.53 20 4.21 5.12 5.75 6.57 7.42 7.75 21 3.79 4.61 5.18 5.91 6.68 6.98 22 3.37 4.10 4.60 5.25 5.94 6.20 23 2.95 3.59 4.03 4.60 5.20 5.43 24 2.53 3.07 3.45 3.94 4.45 4.65 25 2.11 2.56 2.88 3.28 3.71 3.88 26 1.69 2.05 2.30 2.63 2.97 3.10 27 1.26 1.54 1.73 1.97 2.23 2.33 28 0.84 1.02 1.15 1.31 1.48 1.55 29 0.42 0.51 0.58 0.66 0.74 0.78 30 0.00 0.00 0.00 0.00 0.00 0.00 Page 7 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 1.30 1.59 1.78 2.03 2.30 2.40 2 2.61 3.17 3.56 4.06 4.60 4.80 3 3.91 4.76 5 .34 6.10 6.89 7.20 4 5 .22 6.34 7.12 8.13 9.19 9 .60 5 6.52 7 .93 8.90 10.16 11.49 11.99 6 7.82 9.51 10.68 12.19 13.79 14.39 7 9.13 11.10 12.46 14.23 16.08 16.79 8 10.43 12.68 14.24 16.26 18.38 19.19 9 11.74 14.27 16.02 18.29 20.68 21.59 Peak=> 10 13.04 15.85 17.80 20.32 22.98 23.99 11 12 .39 15.06 16 .91 19 .31 21.83 22 .79 12 11 .74 14.27 16.02 18.29 20.68 21 .59 13 11.08 13.48 15 .13 17 .28 19 .53 20.39 14 10.43 12 .68 14.24 16 .26 18.38 19.19 15 9 .78 11.89 13 .35 15 .24 17.23 17.99 16 9 .13 11 .10 12.46 14.23 16.08 16 .79 17 8.48 10.31 11 .57 13.21 14.93 15 .59 18 7 .82 9.51 10.68 12.19 13.79 14.39 19 7 .17 8.72 9.79 11.18 12.64 13.19 20 6.52 7.93 8.90 10.16 11 .49 11.99 21 5 .87 7.13 8.01 9 .15 10.34 10.79 22 5 .22 6.34 7 .12 8 .13 9.19 9.60 23 4.56 5.55 6.23 7.11 8.04 8.40 24 3 .91 4.76 5.34 6.10 6.89 7 .20 25 3 .26 3 .96 4.45 5 .08 5.74 6.00 26 2.61 3 .17 3 .56 4.06 4.60 4 .80 27 1.96 2.38 2.67 3.05 3.45 3.60 28 1.30 1.59 1.78 2.03 2 .30 2.40 29 0 .65 0 .79 0.89 1.02 1.15 1.20 30 0 .00 0.00 0.00 0.00 0 .00 0 .00 Page8 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 0.74 0.90 1.01 1.15 1.30 1.36 2 1.48 1.80 2.02 2.31 2.61 2.72 3 2.22 2.70 3.03 3.46 3.91 4.09 4 2.96 3.60 4.04 4.62 5.22 5.45 5 3.70 4.50 5.05 5.77 6.52 6.81 6 4.44 5.40 6.06 6.92 7.83 8.17 7 5.18 6.30 7.07 8.08 9.13 9.53 8 5.92 7.20 8.08 9.23 10.43 10.89 9 6.66 8.10 9.09 10.38 11.74 12.26 Peak=> I 10 7.40 9.00 10.10 11.54 13.04 13.62 11 7.03 8.55 9.60 10.96 12.39 12.94 12 6.66 8.10 9.09 10.38 11.74 12.26 13 6.29 7.65 8.59 9.81 11.09 11.58 14 5.92 7.20 8.08 9.23 10.43 10.89 15 5.55 6.75 7.58 8.65 9.78 10.21 16 5.18 6.30 7.07 8.08 9.13 9.53 17 4.81 5.85 6.57 7.50 8.48 8.85 18 4.44 5.40 6.06 6.92 7.83 8.17 19 4.07 4.95 5.56 6.35 7.17 7.49 20 3.70 4.50 5.05 5.77 6.52 6.81 21 3.33 4.05 4.55 5.19 5.87 6.13 22 2.96 3.60 4.04 4.62 5.22 5.45 23 2.59 3.15 3.54 4.04 4.56 4.77 24 2.22 2.70 3.03 3.46 3.91 4.09 25 1.85 2.25 2.53 2.88 3.26 3.40 26 1.48 1.80 2.02 2.31 2.61 2.72 27 1.11 1.35 1.52 1.73 1.96 2.04 28 0.74 0.90 1.01 1.15 1.30 1.36 29 0.37 0.45 0.51 0.58 0.65 0.68 30 0.00 0.00 0.00 0.00 0.00 0.00 Page9 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 0.56 0.69 0.77 0.88 0.99 1.04 2 1.13 1.37 1.54 1.76 1.99 2.07 3 1.69 2.06 2.31 2.64 2.98 3.11 4 2.25 2.74 3.08 3.51 3.97 4.15 5 2.82 3.43 3.85 4.39 4.97 5.19 6 3.38 4.11 4.62 5.27 5.96 6.22 7 3.95 4.80 5.39 6.15 6.95 7.26 8 4.51 5.48 6.15 7.03 7.95 8.30 9 5.07 6.17 6.92 7.91 8.94 9.33 Peak=> I 10 5.64 6.85 7.69 8.79 9.93 10.37 11 5.36 6.51 7.31 8.35 9.44 9.85 12 5.07 6.17 6.92 7.91 8.94 9.33 13 4.79 5.83 6.54 7.47 8.44 8.81 14 4.51 5.48 6.15 7.03 7.95 8.30 15 4.23 5.14 5.77 6.59 7.45 7.78 16 3.95 4.80 5.39 6.15 6.95 7.26 17 3.66 4.46 5.00 5.71 6.46 6.74 18 3.38 4.11 4.62 5.27 5.96 6.22 19 3.10 3.77 4.23 4.83 5.46 5.70 20 2.82 3.43 3.85 4.39 4.97 5.19 21 2.54 3.08 3.46 3.95 4.47 4.67 22 2.25 2.74 3.08 3.51 3.97 4.15 23 1.97 2.40 2.69 3.08 3.48 3.63 24 1.69 2.06 2.31 2.64 2.98 3.11 25 1.41 1.71 1.92 2.20 2.48 2.59 26 1.13 1.37 1.54 1.76 1.99 2.07 27 0.85 1.03 1.15 1.32 1.49 1.56 28 0.56 0.69 0.77 0.88 0.99 1.04 29 0.28 0.34 0.38 0.44 0.50 0.52 30 0.00 0.00 0.00 0.00 0.00 0.00 Page 10 14 .00 ... 12.00 Q) 0.. -Q) 10.00 Q) ... 0,,.... ·-"O 8 .00 .0 c :::J 0 u 0 6.00 -Q) Q) Cl) 0) ... 0 4 .00 .s:; 0 II) 0 2.00 0.00 0 Total Pre-Development Vs. Total Post-Development (N o Detention) Peak Discharge Rates 2-Year Storm Event 5 10 15 20 25 Time (Minutes) ---Pre -Development Hydrograph ----Total Post-Development Hydrograph 16.00 ... Q) 14 .00 0.. -Q) 12 .00 Q) ... 0,,.... 10.00 ·-"O .0 c :::J 0 8.00 (.) 0 -Q) 6.00 Q) Cl) 0) ... 0 4 .00 .s:; 0 II) 2.00 0 0 .00 0 Tota l Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Eve nt 5 10 15 20 25 Time (Minutes) Pre -Devel o pment Hydrograph Page 11 Post-Dev elopment Outflow Hydrograph Without Detention 30 30 18 .00 ... 16 .00 Cl> 0.. -14 .00 Cl> Cl> 12.00 u.. o -·-"O 10 .00 .a c ::::J 0 (.) 0 8 .00 -Cl> Cl> (I) O> 6 .00 ... 0 s::. 4 .00 ~ a 2 .00 0 .00 0 Total Pre-Development Vs . Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Eve nt 5 10 15 20 25 Time (Minutes) 30 ---Pre-Development Hydrograph ----Post-Development Outflow Hydrograph Without Detention 25.00 ... Cl> 0.. 20 .00 -Cl> Cl> u.. o-15.00 ·-"O .a c ::::J 0 (.) 0 -Cl> 10 .00 Cl> (I) O> ... 0 s::. 0 5.00 .!!? 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-Dev elopment Hydrograph ----Post-Development Outflow Hydrograph Without Detention Page 12 25.00 ... Q) 0... 20 .00 -Q) Q) ...... () -15.00 ·-"O ..0 c: ::::J 0 () () -Q) 10 .00 Cl> Cl) O> ... 0 .s::. () 5.00 II) 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 With out Detention 25 .00 ... Q) 0... -20 .00 Q) Q) ...... () -15 .00 ·-"O ..0 c: ::::J 0 (.) () -Q) 10.00 Cl> Cl) O> ... 0 .s::. 5.00 () II) 0 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) Pre -Development Hydrograph Page 13 Post-Deve lopment Outflow Hydrograph Without Detention 30 Detention Pond De th Vs. Volume " Elevation Depth Volume (Feet) (Ft3) 296 .25 0.00 0 296 .76 0.51 1,186 297 .00 0 .75 2,473 298 .00 1.75 8,603 298 .25 2.00 10,333 298 .50 2.25 12,148 Detention Pond Depth Vs. Volume 2 .50 2 .00 1.50 ....... -Q) Q) u.. ...., .c -Q. Q) a 1.00 0 .50 0.00 0 2 ,000 4,000 6 ,000 8 ,000 10 ,000 12 ,000 14 ,000 Detention Pond Volume (Cubic Feet) Page 14 Rating Curve For Outlet Control Structure Pipe Dia. (Inches): 8 0 .67 De th Vs. Volume Pipe Length 255 .00 Feet Elevation Depth Discharge (Feet) Ft3/Sec 296 .25 0 .00 0 .00 296 .76 0 .51 0.51 297.00 0 .75 0 .62 298.00 1 .75 0.95 298.25 2.00 1 .02 298.50 2 .25 1 .08 Rating Curve For Outlet Control Structure Depth Vs. Volume 1.50 --<I> <I> LI. ......, .s:: -a. <I> a 1.00 0 .00 0.20 0.40 0.60 0 .80 1.00 1.20 Discharge (Cubic Feet Per Second) Page 15 I Storage Indication Curve 1.20 1.00 -'U c 0 0 .80 0 ~ ... Q) a.. -Q) Q) u.. 0.60 0 :a ::I (.) ...... Q) O> ... 0 0 .40 ..c 0 U) 0 0 .20 0.00 Depth Sto rage Discharge 2s/t 2s/t+O (Feet) (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0 .00 0 0 .00 0 .00 0 .00 0 .51 1,186 0.51 39 .53 40.05 0 .75 2,473 0 .62 82.43 83.06 1.75 8 ,603 0.95 286 .77 287.72 2 .00 10 ,333 1.02 344.43 345.45 2.25 12 ,148 1.08 404.93 406 .01 Storage Indication Curve ~ /- v ~ ~v v / / ( v 0 .00 50 .00 l 00.00 150 .00 200 .00 250.00 300 .00 350 .00 400 .00 450 .00 2s/t+O (Cubic Feet Per Second) P age 16 Inflow I Outflow Simulation 2-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 0.00 296.25 1 0.56 0.56 0.55 0.56 0.01 0.00 296.25 2 1.13 1.69 2.18 2.24 0 .03 0.00 296.25 3 1.69 2.82 4.87 5.00 0.06 0.01 296 .26 4 2.25 3.95 8.59 8.82 0.11 0.02 296.27 5 2.82 5.07 13.32 13.67 0.18 0.06 296.31 6 3 .38 6.20 19.02 19.52 0.25 0.12 296 .37 7 3.95 7.33 25.67 26.34 0.34 0.22 296.47 8 4.51 8.46 33.25 34.13 0.44 0.37 296.62 9 5 .07 9.58 41.79 42.83 0.52 0.52 296.77 10 5.64 10.71 51.41 52 .50 0.54 0 .57 296.82 11 5 .36 10.99 61.27 62.41 0.57 0.63 296.88 12 5 .07 10.43 70 .51 71 .70 0.59 0.68 296.93 13 4 .79 9.86 79 .14 80.37 0.62 0.73 296 .98 14 4.51 9.30 87 .18 88.44 0.63 0 .77 297.02 15 4 .23 8.74 94 .63 95.92 0 .64 0.80 297.05 16 3.95 8.17 101.50 102.81 0.65 0.83 297.08 17 3 .66 7.61 107.78 109.11 0 .66 0 .85 297.10 18 3 .38 7 .05 113.48 114.83 0 .67 0.88 297.13 19 3 .10 6.48 118.60 119.96 0.68 0.90 297.15 20 2.82 5 .92 123.14 124.52 0 .69 0.92 297.17 21 2.54 5 .36 127.11 128.50 0 .70 0.94 297.19 22 2 .25 4 .79 130.50 131 .90 0 .70 0.95 297.20 23 1.97 4 .23 133.32 134.73 0.70 0 .96 297.21 24 1.69 3 .66 135.56 136.98 0.71 0.97 297 .22 25 1.41 3 .10 137.24 138.66 0.71 0 .98 297.23 26 1.13 2.54 138.35 139 .78 0.71 0 .99 297.24 27 0 .85 1.97 138.90 140.32 0.71 0.99 297.24 28 0 .56 1.41 138.88 140.31 0 .71 0 .99 297.24 29 0.28 0.85 138.30 139.72 0.71 0.99 297.24 30 0.00 0.28 137.16 138.58 0 .71 0 .98 297.23 Page 17 Inflow/Outflow Simulation 2-Year Storm Event 14.00 j' ' I ' 12.00 • . • ' I ' I ~ I ' ... I 10 .00 ' • ....... "O I ' c 0 • ... 0 I ' Cl> (/) ..... Cl> 8 .00 a.. -Cl> Cl> u.. 0 :0 :J 6.00 0 -~ 0 E :J 0 4 .00 2 .00 I ... . /" ' I /;.' <~~ ' ' I ' I ' ' I ~ ' ''- I !/ '" <;~ . ' I ' • ' I ' I ' . . " ' ' ·I' '~ I ' ' ' " • I ' ' . ' . ' ' I ' ' . '1 ' 1· ' 'J . .. ' I ~ ~ 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post --• -• -• Post- De velopme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph With Flow · Without Detention Detention Page 18 Inflow I Outflow Simulation 5-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 0.00 296.25 1 0 .69 0.69 0 .67 0 .69 0 .01 0.00 296.25 2 1.37 2 .06 2.65 2.72 0 .03 0.00 296 .25 3 2.06 3.43 5.93 6.08 0 .08 0.01 296 .26 4 2 .74 4.80 10.45 10.72 0 .14 0 .04 296 .29 5 3.43 6.17 16 .19 16.62 0.21 0 .09 296 .34 6 4 .11 7 .54 23 .12 23 .73 0.30 0 .18 296.43 7 4 .80 8.91 31 .21 32 .03 0.41 0.33 296 .58 8 5.48 10.28 40.46 41.49 0 .52 0 .52 296 .77 9 6.17 11.65 51.03 52 .11 0 .54 0.57 296 .82 10 6 .85 13.02 62.90 64.05 0 .57 0.64 296 .89 11 6.51 13 .37 75.06 76 .27 0 .60 0 .71 296 .96 12 6.17 12 .68 86.48 87.74 0 .63 0 .77 297 .02 13 5 .83 11.99 97.18 98.47 0 .65 0 .81 297 .06 14 5.48 11 .31 107.16 108.49 0.66 0.85 297.10 15 5.14 10 .62 116.43 117.79 0 .68 0.89 297 .14 16 4 .80 9 .94 124.99 126.37 0.69 0 .93 297.18 17 4 .4 6 9 .25 132 .83 134.24 0.70 0 .96 297.21 18 4 .11 8.57 139 .97 141.40 0.72 0 .99 297.24 19 3 .77 7 .88 146.40 147.85 0.73 1.02 297.27 20 3.43 7 .20 152 .13 153.60 0 .74 1.05 297 .30 21 3 .08 6.51 157.15 158.64 0.74 1.07 297.32 22 2.74 5.83 161.48 162 .98 0.75 1.09 297.34 23 2.40 5 .14 165.10 166.62 0 .76 1.11 297.36 24 2.06 4.46 168.04 169 .56 0 .76 1.12 297.37 25 1.71 3 .77 170.28 171 .81 0 .76 1.13 297 .38 26 1.37 3 .08 171 .83 173.36 0 .77 1.14 297 .39 27 1.03 2.40 172.69 174.23 0.77 1.14 297.39 28 0.69 1.71 172.87 174.41 0 .77 1.14 297 .39 29 0 .34 1.03 172.36 173.90 0 .77 1.14 297.39 30 0.00 0.34 171 .17 172 .70 0 .77 1.14 297.39 Page 19 Inflow/Outflow Simulation 5-Year Storm Event 16.00 •" ' • ' • ' • .. 14 .00 • ' • ' • ' • ' ' • 12 .00 ~ • ' • ' ,.... "O I ' c 0 0 10.00 Cl> (/) .... Cl> Q. -Cl> Cl> 8 .00 u.. 0 :0 J u -~ 6 .00 0 E J 0 4 .00 2 .00 I ' • ' ' /· -~ ' I .. I ' • ' I ' // ' ' '\ I ' ~ ' ' • ' ' ' ' ' • ' ' • ' . // ',",~ ' • ' • . ' ~ ' . /: ' .. ' I ,' ' ·I .. "~ ' . ' . • ' . I ~\ . ' I ;· '\\: . '. ' ' 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 Page 20 Inflow I Outflow Simulation 10-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 .00 296.25 1 0.77 0.77 0 .75 0.77 0.01 0.00 296 .25 2 1.54 2.31 2.98 3 .06 0 .04 0 .00 296.25 3 2.31 3 .85 6.65 6.83 0.09 0.01 296 .26 4 3.08 5 .39 11 .73 12.04 0.15 0.05 296.30 5 3.85 6.92 18.17 18.65 0.24 0.11 296.36 6 4.62 8.46 25 .95 26 .64 0.34 0.23 296.48 7 5.39 10 .00 35 .03 35 .96 0.46 0.41 296 .66 8 6.15 11 .54 45.52 46 .57 0 .53 0.54 296.79 9 6.92 13.08 57.47 58.59 0.56 0.61 296 .86 10 7 .69 14.62 70 .90 72 .09 0.59 0 .68 296 .93 11 7 .31 15 .00 84 .65 85 .90 0.63 0.76 297.01 12 6.92 14.23 97.59 98 .88 0.65 0.81 297.06 13 6.54 13.46 109 .72 111 .05 0.67 0 .86 297.11 14 6.15 12 .69 121.04 122.41 0 .69 0 .91 297 .16 15 5.77 11 .92 131 .56 132.97 0.70 0 .96 297.21 16 5 .39 11 .16 141.28 142 .72 0.72 1.00 297.25 17 5.00 10 .39 150.20 151 .67 0.73 1.04 297.29 18 4.62 9 .62 158.33 159.82 0.75 1.08 297.33 19 4.23 8.85 165.66 167.18 0.76 1.11 297.36 20 3 .85 8.08 172 .21 173.74 0.77 1.14 297.39 21 3.46 7 .31 177.96 179 .51 0.78 1.17 297.42 22 3 .08 6.54 182.93 184.50 0.78 1.19 297.44 23 2 .69 5 .77 187.12 188.70 0.79 1.21 297.46 24 2 .31 5 .00 190.52 192 .12 0.80 1.23 297.48 25 1.92 4 .23 193.15 194.76 0.80 1.24 297.49 26 1.54 3.46 195.01 196.62 0.80 1.25 297.50 27 1.15 2.69 196.09 197.70 0.81 1.26 297.51 28 0 .77 1.92 196.40 198.01 0.81 1.26 297 .51 29 0 .38 1.15 195.94 197.55 0.81 1.26 297 .51 30 0 .00 0 .38 194.72 196.33 0.80 1.25 297.50 Page 21 Inflow/Outflow Simulation 10-Year Storm Event 18 .00 ti' I ' ' I ' 16 .00 • I ' I .. I ' . ' 14 .00 I .. I , ' I ' ....... "'O 12.00 c 0 0 Cl) (/) ... Cl) Q., 10 .00 -Cl) Cl) u.. 0 :0 8 .00 j (.) -~ 0 E 6.00 j 0 4.00 2 .00 I ' • ' I ""' ' I I ' I ' ' // ··"· .. ~ .. I ' t '-. ' ' I ' ' ... I /:' ·· .. ~ ' • ' ' I ' I .. :l· ' ' ' ~ '" ' ' ' I ,' I ,' ~ ' ·~/ ',~ .. ' , ' I ' ' ~ ', I ' l '~ ' ' ' 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 Page 22 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 0.00 296 .25 1 0 .88 0.88 0.86 0.88 0.01 0.00 296 .25 2 1.76 2.64 3.40 3.49 0.04 0.00 296 .25 3 2.64 4 .39 7.60 7 .80 0.10 0.02 296 .27 4 3.51 6.15 13 .39 13.75 0.18 0.06 296.31 5 4.39 7 .91 20 .76 21.30 0 .27 0 .14 296.39 6 5 .27 9 .67 29 .64 30.42 0.39 0.29 296.54 7 6.15 11.42 40.03 41 .07 0 .52 0.52 296.77 8 7 .03 13.18 52 .12 53 .21 0 .55 0.58 296.83 9 7 .91 14.94 65 .90 67 .06 0 .58 0.66 296.91 10 8 .79 16 .69 81 .35 82 .59 0 .62 0.75 297 .00 11 8.35 17 .13 97 .19 98.48 0 .65 0 .81 297.06 12 7 .91 16 .26 112 .10 113.44 0.67 0.87 297 .12 13 7.47 15 .38 126.09 127.48 0 .69 0.93 297.18 14 7 .03 14.50 139 .16 140.59 0 .71 0.99 297.24 15 6.59 13.62 151 .31 152.78 0 .73 1.04 297.29 16 6.15 12.74 162.55 164.05 0.75 1.10 297.35 17 5 .71 11 .86 172 .87 174.41 0 .77 1.14 297 .39 18 5 .27 10.98 182.29 183.86 0 .78 1.19 297 .44 19 4 .83 10.10 190.80 192.39 0.80 1.23 297.48 20 4.39 9 .23 198.40 200 .02 0 .81 1.27 297.52 21 3 .95 8 .35 205 .11 206 .75 0 .82 1.30 297.55 22 3 .51 7.47 210 .92 212.58 0.83 1.33 297.58 23 3 .08 6.59 215 .83 217.51 0 .84 1.36 297.61 24 2.64 5 .71 219 .86 221.55 0.84 1.38 297.63 25 2 .20 4 .83 222 .99 224.69 0 .85 1.40 297.65 26 1.76 3 .95 225 .24 226.95 0 .85 1.41 297.66 27 1.32 3 .08 226 .60 228.31 0 .86 1.42 297.67 28 0.88 2 .20 227 .09 228 .80 0.86 1.42 297.67 29 0.44 1.32 226 .70 228.41 0 .86 1.42 297.67 30 0 .00 0.44 225.43 227.14 0 .85 1.41 297.66 Page 23 -1'J c 0 0 Cl> 25 .00 20 .00 Ch 15.00 cu Q. Qi Cl> u.. 0 :0 :J u 'i 10.00 0 = :J 0 5.00 0.00 Inflow /Outflow Simulation 25-Year Storm Event I I I I I • I 0 5 Pre----- Developme nt Hydrograph I I I 10 15 20 Time (Minutes) Post-Post- Developme Developme nt Outflow nt Outflow Hydrograph Wit h Without Detention Detention Page 24 25 -·------ 30 Post- Developme nt ·Free- Flow· 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 0.00 296 .25 1 0.99 0.99 0 .97 0 .99 0.01 0.00 296.25 2 1.99 2.98 3 .85 3 .95 0.05 0.00 296 .25 3 2.98 4.97 8.59 8.81 0 .11 0 .02 296.27 4 3 .97 6.95 15.14 15.54 0.20 0.08 296.33 5 4.97 8.94 23.46 24.08 0.31 0 .18 296.43 6 5 .96 10.93 33 .51 34 .39 0.44 0.38 296 .63 7 6.95 12 .91 45 .36 46.42 0.53 0 .54 296.79 8 7 .95 14.90 59 .13 60 .26 0.56 0.62 296.87 9 8 .94 16.89 74 .81 76.02 0.60 0 .71 296.96 10 9.93 18.87 92.40 93 .68 0 .64 0 .79 297.04 11 9.44 19.37 110.44 111.77 0.67 0.87 297 .12 12 8.94 18.38 127.42 128.81 0.70 0.94 297 .19 13 8.44 17.38 143.36 144.80 0.72 1.01 297.26 14 7 .95 16.39 158.26 159.75 0 .75 1.08 297 .33 15 7.45 15.40 172.12 173.65 0 .77 1.14 297 .39 16 6.95 14.40 184.94 186.52 0.79 1.20 297.45 17 6.46 13.41 196.74 198.35 0 .81 1.26 297.51 18 5.96 12.42 207 .51 209.15 0.82 1.32 297 .57 19 5.46 11.42 217.25 218.93 0 .84 1.37 297 .62 20 4.97 10.43 225 .97 227.68 0.85 1.41 297.66 21 4.47 9 .44 233 .67 235.41 0 .87 1.45 297.70 22 3.97 8.44 240.36 242.12 0 .88 1.49 297 .74 23 3.48 7.45 246 .04 247 .81 0 .89 1.52 297.77 24 2.98 6.46 250 .71 252.49 0 .89 1.55 297.80 25 2.48 5.46 254 .37 256 .17 0.90 1.57 297.82 26 1.99 4.47 257 .03 258.84 0.90 1.58 297 .83 27 1.49 3.48 258 .69 260.51 0 .91 1.59 297.84 28 0.99 2.48 259 .36 261.18 0.91 1.60 297.85 29 0.50 1.49 259 .04 260.85 0.91 1.59 297 .84 30 0.00 0 .50 257.72 259.53 0.91 1.59 297.84 Page 25 Inflow/Outflow Simulation 50-Year Storm Event 25 .00 " I " I " I ' I ' 20 .00 I ' ' I ' • ' I ' ...... "O I " c ' 0 I () I ' Q) 15 .00 Cl) ... Q) Q. -Q) Q) u.. () 1i ::::J u ....., 10 .00 ~ 0 ~ ::::J 0 ' 5.00 " ' 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post-............... Post- Developm e Developme Deve lopme Developm e nt nt Outflow nt Outflow nt "Free- Hydrograph Hyd ro g raph With Fl ow· With o ut Dete ntion Det e nti o n P a ge 26 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 0.00 296.25 1 1.04 1.04 1.01 1.04 0 .01 0 .00 296 .25 2 2.07 3 .11 4.02 4 .12 0.05 0.01 296 .26 3 3 .11 5.19 8.97 9 .20 0 .12 0 .03 296 .28 4 4 .15 7 .26 15.81 16 .22 0.21 0.08 296 .33 5 5.19 9.33 24 .50 25.14 0.32 0.20 296.45 6 6.22 11.41 34 .99 35 .91 0.46 0.41 296.66 7 7 .26 13.48 47.40 48.47 0 .53 0.55 296 .80 8 8.30 15.56 61 .81 62 .95 0.57 0.63 296 .88 9 9 .33 17.63 78 .22 79.44 0 .61 0 .73 296 .98 10 10.37 19 .70 96.63 97 .92 0.65 0 .81 297.06 11 9 .85 20 .22 115.50 116.85 0.68 0 .89 297.14 12 9 .33 19 .19 133.27 134.68 0 .70 0.96 297.21 13 8.81 18.15 149.96 151.42 0.73 1.04 297.29 14 8.30 17 .11 165.56 167.07 0.76 1.11 297.36 15 7 .78 16 .07 180.07 181 .63 0.78 1.18 297.43 16 7 .26 15.04 193.50 195.11 0 .80 1.25 297 .50 17 6.74 14.00 205 .86 207.50 0 .82 1.31 297.56 18 6.22 12.96 217 .14 218 .82 0 .84 1.37 297.62 19 5 .70 11 .93 227 .36 229 .07 0 .86 1.42 297.67 20 5 .19 10.89 236.50 238 .25 0.87 1.47 297 .72 21 4 .67 9.85 244 .59 246 .36 0.88 1.51 297 .76 22 4 .15 8.81 251 .61 253 .40 0 .90 1.55 297.80 23 3.63 7 .78 257 .58 259.39 0 .90 1.59 297.84 24 3.11 6.74 262 .50 264.32 0 .91 1.61 297 .86 25 2.59 5.70 266 .36 268.20 0.92 1.64 297 .89 26 2.07 4 .67 269 .18 271 .03 0 .92 1.65 297 .90 27 1.56 3 .63 270 .96 272.81 0.93 1.66 297 .91 28 1.04 2 .59 271 .70 273 .55 0 .93 1.67 297 .92 29 0 .52 1.56 271.40 273 .25 0 .93 1.67 297 .92 30 0 .00 0.52 270 .07 271 .92 0 .92 1.66 297 .91 P a g e 27 -"O c 0 ~ 25.00 20 .00 Cl) 15.00 a; a.. Q; QI ... 0 1i ::::J ~ ~ 10 .00 0 =§ 0 5.00 0.00 Inflow/Outflow Simulation 100-Year Storm Event 0 5 Pre-- Developme nt Hydrograph - I I I I I I I I -- • I I ' ' I 10 ' ' ' ... ' .. ' ' ' ' ' 15 20 Time (Minutes) Post -Post- Developme Developm e nt Outflow nt Outflow Hydrograph With Without Detention Det e nti o n Page 28 25 30 .. --... -... Post- Developme nt "Free- Flow· 9.00 8.00 7.00 B 6.oo c: 0 0 C1> (f) ~ Q. 5.00 Q; C1> u.. 0 :0 ~ 4.00 ~ 0 =§ 0 3 .00 2.00 l.00 0 .00 0 Inflow/Outflow Simulation 2-Year Storm Event 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ---•Total Post-Develo p ment Hyd rograph P age 29 Inflow/Outflow Simulation 5-Year Storm Event 12 .00 10.00 -8.00 'O c 0 0 Q) en ... Q) 0.. -Q) Q) 6 .00 u.. 0 :0 :;, u ......, ~ 0 E :;, 0 4.00 2 .00 0.00 0 5 10 15 20 25 30 Time (Minutes) ----Pre-Development Hydrograph ----To t a l Post-Development Hydrograph P age 30 Inflow/Outflow Simulation 10-Year Storm Event 12.00 10.00 ...... 8 .00 "O c: 0 0 G> Cl) -G> Q., -G> G> 6.00 ...... 0 :0 ::7 (.) -~ 0 ~ ::7 0 4.00 2 .00 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre -Devel o pm e nt Hydrograph ----Total Post-Development Hydrograph Page 31 Inflow/Outflow Simulation 25-Year Storm Event 14.00 12 .00 10.00 -"O c 0 () Q) Cl) ... 8 .00 Q) 0... -Q) Q) u.. () :0 ::::J () 6.00 ........ ~ 0 ~ ::::J 0 4 .00 2.00 0.00 0 5 10 15 20 25 30 Time (Minutes) ----Pre-Development Hydrograph ----Total Post-Development Hydrograph Page 32 Inflow/Outflow Simulation 50-Year Storm Event 16.00 14.00 12 .00 --"O c 0 10.00 0 Q) Cl) ... Q) 0.. -Q) Q) 8 .00 LL. 0 :a ::::J () .._, ~ 0 6.00 == ::::J 0 4.00 2.00 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Po st-Development Hydrograph Page 33 Inflow/Outflow Simulation 100-Year Storm Event 12.00 -,, c: 0 10 .00 0 <I> (/) ... <I> a.. -<I> <I> 8 .00 u.. 0 :0 :::> (.) -~ 0 6 .00 E :::> 0 4.00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Post-Deve lopment Hydrograph Page 34 Detention Pond Storage Volumes as Percent of Maximum Volume 100% 90% 80% 70% Q) E ;::, 0 60% > E ;::, E ')( 50% 0 ~ 15 -40% c Q) 0 ... Q) Q. 30% 20% 10% 0% 2-year 5-year 10-year 25-year 50-year 100-year Design Storm Storm Simulation Synopsis 2-ear 5-ear 10-ear 25-ear 50-ear 100-ear Storm Depth 0.99 1.14 1.26 1.42 1.60 1.67 Storm Elevation 297 .24 297 .39 297 .51 297 .67 297 .85 297.92 Storm Volume 3930 4893 5601 6576 7664 8096 Maximum Capacity 12148 12148 12148 12148 12148 12148 Percent of Capacity 32% 40% 46% 54% 63% 67% Page 35 t:, •, I ~ I GARRETT ENGINEERING PH . 409-846-2688 4444 CARTER CREEK PKWY . SUITE 108 BRYAN , TEXAS 77802 VICTORIA BANK & TRUST JOO() BRIARCREST • BRYAN, TEXAS 77802 MEMBER: VICTORIA BA NKSHARES , I NC./FDIC 1135 14540 " 88 -2511m1 I _ -z.. i..... __ 1 9 _ 1 s-835 ~I __ __,.__,____ I~ / $ / D 0 . -C-c1 I' . f FO R ---'~--=D_P--'/U'---~-~_,,' '--------- ACCOUNT NO . ___________________ _ 377891 . I l J ,.,_, q ;:;-zn ~~ ~Yd ·"~- FOR~"L575=--=--p~,, ----::Cf=-t-1 -ti-;-·VJ -0/2---:u~' 1 --f,S'r-~ ;tj'< ~,1/C~/~a -=-:-g c 7? -- CITY OF 0/:LEGE ST A TION $ im A ~ RECEIVED OF Q))/)vtf Paid by _ Check I lJ :J/G ash __ _ Wt • t Engineer's Estimate For Water Improvements To ~eathel'ln<Salf mag9:::CCqm&JP College Station, Brazos County, Texas October, 1995 ,. ,,. -. ~ ,.~ ' 11-j qJ :_ ., t IL f (. )( ••• "• ~ t I I t • • I { ~ " ' .:1 .. lf.'Jt.~. .···~~u·~ --~-.. 1. 6" Diameter C900 -Class 200 P.V.C . 49 L.F. $16 .00 Water Line (5 -7 feet) 2 . 24"X6" M.J. Tapping Saddle w/6" M.J. 1 Ea . $5,700.00 Taooinq Valve and Box 3 . Standard City Of College Station 1 Ea . $1,400 .00 Fire Hydrant w/appurtenances and extra-depth extensions 4. Trench Safety 1 L.S . $49 .00 Total Amount of Cost For Water Improvements: " I ~ ( , I $784.00 $5,700.00 $1,400.00 $49.00 $7,933.00 {' ( . I \ ' t ..... I\'\ '·. /-.. > • •'. OCT-20 08:51 PATTERSON * ARCHITECTS ~ 40!31165004 P01 FAX TRANSMISSION COVER SHEET COMPANY: __ F_ir_e_P_r_ev_e_n_ti_o_n ________ . TELEPHONE NUMBER: 764-378 l --------- FAX NUMBER: 764-3403 PROM: Abigail Butler ------------------------ DATE: 10-20-95 ---------- NUMBER OF PAGES TO FOLLOW: 1 ------ If you do not recieve all of the pages , please call back as soon as possible . 2402 Brcmdmoor Duilding A Suite 201 Bry a n, Texas 77802 PATTERSON* ARCHITECTS voice -409 776 0809 fax • 409 776 5004 NOTES: Following is an enlarged detail of the tire hydrant location at A-Neatherlin Self-Storage that has been through the Project Review Committee with the City of College Station. TI1e committee requested this detail for ve1ification that there is plenty of room on the island for the hydrant. I would like for you to review f.Uld cmillTCnt. If you need anymore infonnat .ion, please can. We would like to clear up this matter a~ soon a~ possible . Timnk you. OCT-20 08:58 PATTERSON * ARCHITECTS + I I ( , •.. b ' ln ~ 409'1'1 65004 P02 + i ' \1 : I ,· ,. t. ~f;p fONU~ I . :" .'. 6 '' f2...AJ cu ~ L DOCORA Tivt:: IRON Fr-Ncr: - ~-4----+---FIRE HYD RANT - - - 11/2"=1'-0" 0+ FIRE HYDRANT DETAIL + JOB BY 9438-Ncu!hc.; ·rlin Sdf-Storngt! AB ' - 1: •' DA' 10/11 . '\A~ :)IAA ~i,/ cf ~f)O?V~j I) w.'$ f ~OtM /'fl ~I f' ;)Wfl{-'lnr., '>S.)i1+ ?JV!$ ( rn5s-?JpfrJ -fO\A 'J_J-tJ 11/o/ Jo :JjJ t~ ?fl?MA ~lA?WlM<r) JcJJ ·1 ·$~ c .. 'M'7J)':J ~ _,,,, ~v?l-v""G>'/ r;W?;>fA! a'1;J -ff)0'1-f ! fY} f?W .. Nl..(J.J ~!"'j -:V~ ( ..Ut:>UJ~d:,p-p_1w 11/0/ P,?--:U) SLAl?/d ~~J_ -~LS.t/1 .la '!A?V,1 CUJ -........--===-: u.' ~lt-f>?;) N , V No. 1. 2. 3. 4. 5. 6. Engineer's Estimate For Water Improvements To Neatherlin Self Storage Complex College Station, Brazos County, Texas June, 1995 Estimated Unit Unit Quant it Price 6" Diameter C900 -Class 200 P.V.C. 109 L.F . $i 5.00 $1 ,635.00 Water Line O -5 feet 6" Diameter C900 -Class 200 P.V.C. 91 L.F . $16 .00 $1,456.00 Water Line 5 -7 feet 24"X6" M.J. Tapping Saddle w/6" M.J. Ea . $5,700 .00 $5,700.00 Ta in Valve and Box 6"X90 De ree Ea . $250 .00 $250.00 Standard City Of College Station Ea. $i ,400 .00 $i ,400.00 Fire H drant w/a urtenances Trench Safet L.S . $9i .00 $91 .00 Total Amount of Cost For Water Improvements: $10,532.00 . &)14/q( t. JL-. ~i r st Review_ for C=~ ff?@:ine«r~._::g~- Oivision ..) Name DRAINAGE COMPUTATIONS /or NEATHERLJN SELF STORAGE COMPLEX 4004 South Texas A venue College S(atio11, Brll%0S County, Texas Prrparrd for Kenneth Neatherlin P.O. Box 3321 Bryan, Texas 77805 Telephone: ( 409) 778-4663 Prepared by.· Garrett Engineering , 4444 Carter Creek Parkway -Suite 1 O.S Bryan, Texas 77802 Telephone: ( 409) 846-2688 * September 1995 * DRAINAGE COMPUTATIONS for NEATHERLIN SELF STORAGE COMPLEX 4004 South Texas A venue College Station , Brazos County, Texas Prepared for Kenneth Neatherlin P.O. Box 3321 Bryan, Texas 77805 Telephone: (409) 778-4663 Prepared b_y .· · ~--~ Garrett Engineering _ .......... ~;.~~'-t.~~"~ ~· 4444 Carter Creek Parkway -Suite 1 O~~~~ ......... ~~~,~'.~ . Bryan , Texas 77802 ft)/·· ~--··~·~~~: .... >/ Telephone: (409) 846-2688 i_~ .. = ... , ,j \?.:.s~:: o )~~ ,,, .. .. • J ./r;.:; J \ ... · . ."~tG~lc:.~;:~f):::.· ,,, ~1:;:.s··;· :n,_\.. .: . ,, .... _ ; ~ .. ,.,,. ....... ''''"-'I: ,.. .... * September 1995 * e storag;~~~ The total drainage area tributary to the project is 3.33 acres . The pre-developmen -off coefficient was estimated to be 0.40. Assuming a worst case scenario, the entire developed area was considered to be impervious with a post-development run -off coefficient of 0.90 in determining the drainage calculations . A detention facility will be constructed in the southwestern portion of the property in keeping with the existing contours and optimal flow patterns. 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. In this case, the detention pond will collect, store and meter run-off from 0.99 acres, the developed area of the project site. Since all generated runoff from th e developed surface area will be routed through the pond, "free-flow " will consist of the remaining 2.34 acres of the site with a runoff coefficient comparable to the orginal pre - development value of 0.40 . Thes e report calculations are summarized according to the following methodology. Beginning on page 3, based on the total tributary drainage area of the project (3.33 acres), the pre-development run-off coefficient (assumed 0.40), and a minimum time of concentration of 10 minutes, the relative pre-development peak di scharge 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 th e peak discharge rate in cubic feet per second, "C " is the run-off coefficient. assumed to be 0.40 in the pre- dev elopment condition, "I'' is the storm intensity in inches per hour, and "A" is the area of the drainage basin in a cres . Computations on page 4 are based on the tributary area of 3.33 acres, the post-developmf'.ni run-off coefficient of 0.90, a minimum time of concentration of 10 minutes, to yield the relative pre-development peak discharge rate ("Q"). The Rational Method was again utilized to compute the estimated peak post-development di scharge 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. The "C" variable is the run-off coefficient (In the post- development condition "C" is assumed to be 0.90. Generally, the post-development coefficient is weighted ac cording to the relative amounts of pervious and impervious surface area. However, in this case, the total amount of surface area is taken as impervious .) "I" represents the rainfall intensity in inches per hour, and similarly "A" is the area of the basin in acres . Comparison of the peak pre-development discharge rate to the post-development discharge rate is included in th e re port to aid the designer in establishing a preliminary "target" of detention volwne required. This preliminary estimate is determined as the volume difference generated between the pre-development and post- de ve lopment hydrographs. (S ee pages 11-13 for pre-development and post-development hydrographs.) Please note that the post-development hydro graph shown on these same graphs assumes no detention at all , therefore refl ecting the scenario that there is no lag in runoff discharge and all water is allowed to "free-flow " unrestricted off the property . Pages 5 and 6, respectively , provide information concerning the post-development run-off that is not routed through the detention facility, "free flow", and the post-development run-off that is routed through the dete ntion facility and retained on s ite. Page 1 Page 7 and page 8 are tabulations of the pre-development and the post-development hydrographs based on the computations performed on pages 3 & 4. The post-development hydrograph assumes no detention to facilitate direct comparison in the pre-and post-development conditions. Pages 9 & 10 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 6 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 10 is derived. The hydrograph is triangular in shape and is based on the standard SCS unit bydrograph 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 to, the relative 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 14 presents a data tabulation and a depth versus volume graph of the detention facility . Pag 15 d a rating curve for the proposed outlet control structure. A circular pipe c \was _>ha en ~u to the disch e ratio characteristics associated with the anticipated headwater depth. e pipe diameter 8 inches or 7 feet was selected . This value was determined from the following equation for headw e epth, · eet), H = ( ( ( 2.5204 ( 1 + K)) I o4] + ( ( 466.18 n2 L ( 1 + K)) I 016/3 ] '.\; . \), v D I 0 2 " " · entrance loss coefficient ( K = 0.50 for this case). "D" is the diameter of the pipe in • ...:x:!" feet. "I f is the length of culvert in feet. "Q" is the design discharge rate in cublic feet per second. "n" is ~ing's roughness coefficient (n = 0.013 for concrete pipe), and "H" is the headwater depth in feet age Y6 presents a tabulation of the relationship between discharge from the detention facility and the dime sionless quantity 2S/t-O. Also presented is a Storage Indication Curve for the detention facility based on tte orementioned physical characteristics of the detention pond, storage volume, inflow hydrograph, and . ting curve for the outlet structure. The storage indication curve as shown on page 14 is a graphical solution to the equation presented in the "Drnina2e Policy And Desijm Stanciards" as follows: 2s1 (I 1 + Iz) + (----------------01) dt 2s2 = (-------------+ Oi) dt Page 17 through page 28 present simulations of the 2, 5, 10, 25, 50, and 100 year storm events. The first page of c al:b storm simulation represents the tabulated data for the storm event. The maximtim depth achieved in the detention pond during each simulation is shown in the table and is the time at during which this maximum depth occurs from the onset 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 can be found in the table. The second page of each storm simulation represents the pre-development hydrograph, the post-development bydrograph (with no detention). the post-development hydrograph as routed through the detention pond, and post-development "free-flow" hydrograph for each storm event Page 29 through page 34 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 seen from these same hydrographs that the post- development peak discharge rates have been slightly decreased in comparison to the 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 both the detention pond outlet control structure and project site are controlled to be less than the pre-development peak discharge rates with the use of the proposed detention facilities. Subsequent peak post-development discharge velocities are projected to be within manageable limits. Page 2 De t er mine T otal Pre-Development Peak St o rm Water Di scharge Rat es Tributary Area ("A"): 3 .33 Acres Pervious Area : 3 .33 Acres Im pervio us Area: 0 .00 Acres Run-Off C o efficient ("Cwt"): 0.40 Time Of Concentration ("T/c"): Woodla nds: 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): S lope (%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: 8.43 5-Year: 10.25 10-Year: 11 .50 25-Year: 13.14 50-Year: 14.85 100-Y 15.50 Page3 c = 0.40 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 Seco nd Feet I Second Determine Post-development Peak Storm Water Dischar e No Detention Tributary Area ("A"): 3 .33 Acres Pervious Area : Impervious Area : ~res ~res Run-Off Coefficient ("Cwt"): 0.55 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 C= 0.40 C= 0 .90 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Peak Discharge Rate ("Q"): 2-Year: 11.56 Cubic Feet I Second 5-Year: 14.05 Cubic Feet I Second 10-Year: 15.78 Cubic Feet I Second 25-Year: 18.02 Cubic Feet I Second 50-Year: 20.37 Cubic Feet I Second 100-Year: 21.26 Cubic Feet I Second Comparis on Of Pre development And Post-develo ment Peak Dischar e Rates Predevelopment Post -Development Increase 2-Year: 8.43 Ft3/sec 11 .56 Ft3/sec 3 .13 Ft3/sec 5-Year: 10.25 Ft3/sec 14.05 Ft3/sec 3 .81 Ft3/sec 10-Year: 11 .50 Ft3/sec 15.78 Ft3/sec 4 .27 Ft3/sec 25-Year: 13.14 Ft3/sec 18.02 Ft3/sec 4.88 Ft3/sec 50-Year: 14.85 Ft3/sec 20 .37 Ft3/sec 5 .52 Ft3/sec 100-Year: 15.50 Ft3/sec 21.26 Ft3/sec 5 .76 Ft3/sec Preliminary Determ in ation Of Detention Pond Volume 2-Year: 3.13 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 2 ,818 Cubic 5-Year: 3.81 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 3,427 Cubic 10-Year: 4 .27 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 3 ,847 Cubic 25-Year: 4 .88 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 4,393 Cubic 50-Year: 5 .52 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 4,966 Cubic 100-Year: 5 .76 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 5 ,185 Cubic P age4 Feet Feet Feet Feet Feet Feet Determine Post-Development 11 Free-Flow 11 Peak Storm Water Discharge Tributary Area ("A"): 2.34 Acres Pervious Area : 2 .34 Acres Impervious Area : 0.00 Acres Run-Off Coefficient ("Cwt"): 0.40 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: 5 .92 5-Year: 7 .20 10-Year: 8.08 25-Year: 9.23 50-Year: 10.43 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 100-Year: CW,~bic Feet I Second Page5 Determine Post-Development Flow Into Detention Pond Tributa ry Area ("A"): ~Acres Pervious Area : Impervious Area : ~~cres ~cres Run -Off Coefficient ("Cwt"): 0 .90 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: 5.64 5-Year: 6.85 10-Year: 7 .69 25-Year: 8.79 50-Year : 9 .93 100-Year: 10.37 P age 6 C= 0 .40 C = 0 .90 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 0.84 1.02 1.15 1.31 1.48 1.55 2 1.69 2.05 2.30 2.63 2.97 3.10 3 2.53 3.07 3.45 3.94 4.45 4.65 4 3.37 4.10 4.60 5.25 5.94 6.20 5 4.21 5.12 5.75 6.57 7.42 7.75 6 5.06 6.15 6.90 7.88 8.91 9.30 7 5.90 7.17 8.05 9.19 10.39 10.85 8 6.74 8.20 9.20 10.51 11.88 12.40 9 7.58 9.22 10.35 11.82 13.36 13.95 Peak=> • 10 8.43 10.25 11.50 13.14 14.85 15.50 11 8.01 9.73 10.93 12.48 14.11 14.73 12 7.58 9.22 10.35 11.82 13.36 13.95 13 7.16 8.71 9.78 11.17 12.62 13.18 14 6.74 8.20 9.20 10.51 11.88 12.40 15 6.32 7.69 8.63 9.85 11.14 11.63 16 5.90 7.17 8.05 9.19 10.39 10.85 17 5.48 6.66 7.48 8.54 9.65 10.08 18 5.06 6.15 6.90 7.88 8.91 9.30 19 4.63 5.64 6.33 7.22 8.17 8.53 20 4.21 5.12 5.75 6.57 7.42 7.75 21 3.79 4.61 5.18 5.91 6.68 6.98 22 3.37 4.10 4.60 5.25 5.94 6.20 23 2.95 3.59 4.03 4.60 5.20 5.43 24 2.53 3.07 3.45 3.94 4.45 4.65 25 2.11 2.56 2.88 3.28 3.71 3.88 26 1.69 2.05 2.30 2.63 2.97 3.10 27 1.26 1.54 1.73 1.97 2.23 2.33 28 0.84 1.02 1.15 1.31 1.48 1.55 29 0.42 0.51 0.58 0.66 0.74 0.78 30 0.00 0.00 0.00 0.00 0.00 0.00 Page 7 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 1.16 1.41 1.58 1.80 2 .04 2.13 2 2.31 2.81 3 .16 3 .60 4 .07 4 .25 3 3.47 4.22 4 .73 5.41 6.11 6.38 4 4 .62 5.62 6.31 7 .21 8.15 8.51 5 5 .78 7 .03 7 .89 9 .01 10.18 10.63 6 6.94 8.43 9.47 10.81 12.22 12.76 7 8.09 9.84 11 .04 12 .61 14.26 14 .89 8 9.25 11 .24 12 .62 14.41 16 .29 17 .01 9 10.40 12 .65 14 .20 16.22 18.33 19.14 Peak=> 10 11 .56 14.05 15.78 18.02 20.37 21.26 11 10 .98 13.35 14 .99 17.12 19 .35 20.20 12 10.40 12.65 14.20 16.22 18.33 19.14 13 9 .82 11 .95 13.41 15.31 17.3 1 18 .08 14 9 .25 11 .24 12 .62 14.41 16.29 17.01 15 8 .67 10.54 11 .83 13 .51 15.28 15 .95 16 8.09 9 .84 11 .04 12 .61 14.26 14.89 17 7 .51 9.14 10.25 11 .71 13.24 13.82 18 6.94 8.43 9.47 10 .81 12 .22 12 .76 19 6.36 7.73 8 .68 9.91 11.20 11.70 20 5 .78 7 .03 7.89 9 .01 10.18 10.63 21 5.20 6.32 7 .10 8 .11 9 .17 9 .57 22 4 .62 5 .62 6.31 7.21 8.15 8.51 23 4.05 4 .92 5 .52 6.3 1 7 .13 7.44 24 3.47 4.22 4 .73 5.41 6.11 6.38 25 2.89 3 .51 3 .94 4 .50 5 .09 5.32 26 2.31 2.81 3 .16 3 .60 4 .07 4 .25 27 1.73 2.11 2.37 2.70 3.06 3 .19 28 1.16 1.41 1.58 1.80 2.04 2.13 29 0 .58 0 .70 0 .79 0 .90 1.02 1.06 30 0 .00 0.00 0 .00 0 .00 0 .00 0.00 P ag e8 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 0.59 0.72 0.81 0.92 1.04 1.09 2 1.18 1.44 1.62 1.85 2.09 2.18 3 1.78 2.16 2.42 2.77 3.13 3.27 4 2.37 2.88 3.23 3.69 4.17 4.36 5 2.96 3.60 4.04 4.62 5.22 5.45 6 3.55 4.32 4.85 5.54 6.26 6.54 7 4.15 5.04 5.66 6.46 7.30 7.63 8 4.74 5.76 6.47 7.38 8.35 8.72 9 5.33 6.48 7.27 8.31 9.39 9.80 Peak=> ' 10 5.92 7.20 8.08 9.23 10.43 10.89 11 5.63 6.84 7.68 8.77 9.91 10.35 12 5.33 6.48 7.27 8.31 9.39 9.80 13 5.03 6.12 6.87 7.85 8.87 9.26 14 4.74 5.76 6.47 7.38 8.35 8.72 15 4.44 5.40 6.06 6.92 7.83 8.17 16 4.15 5.04 5.66 6.46 7.30 7.63 17 3.85 4.68 5.25 6.00 6.78 7.08 18 3.55 4.32 4.85 5.54 6.26 6.54 19 3.26 3.96 4.45 5.08 5.74 5.99 20 2.96 3.60 4.04 4.62 5.22 5.45 21 2.66 3.24 3.64 4.15 4.70 4.90 22 2.37 2.88 3.23 3.69 4.17 4.36 23 2.07 2.52 2.83 3.23 3.65 3.81 24 1.78 2.16 2.42 2.77 3.13 3.27 25 1.48 1.80 2.02 2.31 2.61 2.72 26 1.18 1.44 1.62 1.85 2.09 2.18 27 0.89 1.08 1.21 1.38 1.57 1.63 28 0.59 0.72 0.81 0.92 1.04 1.09 29 0.30 0.36 0.40 0.46 0.52 0.54 30 0.00 0.00 0.00 0.00 0.00 0.00 Page9 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 0.56 0.69 0.77 0.88 0.99 1.04 2 1.13 1.37 1.54 1.76 1.99 2.07 3 1.69 2.06 2.31 2.64 2.98 3.11 4 2.25 2.74 3.08 3.51 3.97 4.15 5 2.82 3.43 3.85 4.39 4.97 5.19 6 3.38 4.11 4.62 5.27 5.96 6.22 7 3.95 4.80 5.39 6.15 6.95 7.26 8 4.51 5.48 6.15 7.03 7.95 8.30 9 5.07 6.17 6.92 7.91 8.94 9.33 Peak=> I 10 5.64 6.85 7.69 8.79 9.93 10.37 11 5.36 6.51 7.31 8.35 9.44 9.85 12 5.07 6.17 6.92 7.91 8.94 9.33 13 4.79 5.83 6.54 7.47 8.44 8.81 14 4.51 5.48 6.15 7.03 7.95 8.30 15 4.23 5.14 5.77 6.59 7.45 7.78 16 3.95 4.80 5.39 6.15 6.95 7.26 17 3.66 4.46 5.00 5.71 6.46 6.74 18 3.38 4.11 4.62 5.27 5.96 6.22 19 3.10 3.77 4.23 4.83 5.46 5.70 20 2.82 3.43 3.85 4.39 4.97 5.19 21 2.54 3.08 3.46 3.95 4.47 4.67 22 2.25 2.74 3.08 3.51 3.97 4.15 23 1.97 2.40 2.69 3.08 3.48 3.63 24 1.69 2.06 2.31 2.64 2.98 3.11 25 1.41 1.71 1.92 2.20 2.48 2.59 26 1.13 1.37 1.54 1.76 1.99 2.07 27 0.85 1.03 1.15 1.32 1.49 1.56 28 0.56 0.69 0.77 0.88 0.99 1.04 29 0.28 0.34 0.38 0.44 0.50 0.52 30 0.00 0.00 0.00 0.00 0.00 0.00 Page 10 12.00 .... CJ) 10.00 0.. -CJ) CJ) 8.00 LL 0 ....... ·-"O .0 c ::::J 0 6 .00 0 0 ....., CJ) CJ) Cl) O> 4.00 .... 0 .c. 0 II) 2 .00 0 0 .00 0 Total Pre -Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 2-Year Storm Event 5 10 15 20 25 Time (Minutes) ---Pre -Development Hydrograph ----Total Post-Developm ent Hydrograph 16 .00 .... CJ) 14.00 0.. -CJ) 12.00 CJ) LL 0 ....... 10.00 ·-"O .0 c ::::J 0 8.00 0 0 ....., CJ) 6 .00 CJ) Cl) O> .... 0 4 .00 .c. 0 II) 2 .00 0 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event 5 10 15 20 25 Time (Minutes) Pre-Dev elopment Hydrograph ----Post-Development Outflow Hydrograph Without Detention Page 11 30 30 .... Q) c... -Q) Q) u. o -·-'O ..0 c ::::J 0 () 0 -Q) Q) V) O> .... 0 .s:: 0 U) i5 .... Q) c... -Q) Q) u. o -·-'O ..0 c ::::J 0 () 0 -Q) Q) V) O> .... 0 .s:: 0 U) i5 16.00 14.00 12 .00 10 .00 8 .00 6 .00 4 .00 2 .00 0 .00 0 Total Pre-Development Vs. Total Post -Development (N o Detention) Peak Discharge Rates 10-Year Storm Even t 5 10 15 20 25 Time (Minutes) 30 Pre-Development Hydrograph ----Post-Development Outflow Hydrograph Without Detention 20 .00 18 .00 16 .00 14.00 12 .00 10.00 8 .00 6 .00 4.00 2 .00 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-D evelopment Hydrograph ----Post-Development Outflow Hydrograph Without Detention Page 12 25 .00 ... Q) 0... 20 .00 "$ Q) u.. 0 ....... 15 .00 ·-"O .a c ::J 0 0 0 ....., Q) 10 .00 Q) Cl) O> ... 0 .c ~ 5 .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 -Dev e lopment Hydrograph ----Post-Developm ent Outflow Hydrogra p h With o ut Det e nti on ... Q) 0... -Q) Q) u.. 0 ....... ·-"O .a c ::J 0 0 0 ....., Q) Q) Cl) O> ... 0 .c 0 II) 0 25 .00 20 .00 15.00 10 .00 5.00 0 .00 0 Total Pre -Development Vs. Total Post -Development (No Detention) Peak Discharge Rates 100-Year Storm Event 5 10 15 20 25 nme (Minutes) ----Pre -Dev elopment Hydrograph ----Post -Developm e nt Outflow Hy drograph Wi th o ut Detention Page 13 30 Detention .Pond De th Vs. Volume Elevation Depth Volume (Feet) (Ft3) 296 .25 0 .00 0 296 .76 0.51 1,186 297 .00 0 .75 2,473 I 298 .00 1.75 8 ,603 ~~ 298 .25 2.00 ~ 298 .50 2.25 8 Detention Pond Depth Vs. Volume 2.50 2.00 1.50 ......... -Cl> Cl> ~ .._, ~ -a. Cl> a l.00 0 .50 0.00 0 2 ,000 4 ,000 6 ,000 8 ,000 10 ,000 12 ,000 14 ,000 Detention Pond Volume (Cubic Feet) P a ge 14 Rating Curve For Outlet Control Structure Depth Vs. Volume Elevation 296.25 296.76 297.00 298 .00 298.25 298.50 Depth (Feet) 0.00 0.51 0 .75 1 .75 2.00 2 .25 Pipe Dia. (Inches): Pipe Length Discharge Ft3/Sec 0.00 1.46 1.77 2 .71 2.89 3.07 ~ Rating Curve For Outlet Control Structure Depth Vs. Volume l.50 ....... -Cl> Cl> u.. .._, .c -a. Cl> 0 l.00 0 .00 0 .50 l.00 1.50 2.00 2.50 3.00 Discharge (Cubic Feet Per Second) Page 15 3.50 I Storage Indication Curve 3.50 3.00 ~ 2.50 c 0 0 ~ &. -2.00 Q) Q) u.. 0 :0 :::7 ~ 1.50 Q) 0) 0 .c. ~ 1.00 0.50 0 .00 Depth Sto rage Discharge 2s/t 2s/t+O (Feet) (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0 .00 0 0 .00 0.00 0.00 0 .51 1,186 1.46 39 .53 41 .00 0.75 2,473 1.77 82.43 84.21 1.75 8,603 2 .71 286.77 289 .47 2.00 10 ,333 2 .89 344.43 347.33 2.25 12 ,148 3 .07 404.93 408.00 Storage Indication Curve ~ --v ~ v v / ~ ./ v l ' l , 0 .00 50 .00 l 00.00 150.00 200.00 250.00 300 .00 350.00 400 .00 450.00 2s/t+O (Cubic Feet Per Second) P age 16 Inflow I Outflow Simulation 2-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 0.00 296.25 1 0.56 0.56 0.52 0.56 0.02 0.00 296.25 2 1.13 1.69 2.06 2.21 0.08 0.00 296.25 3 1.69 2.82 4.53 4.88 0.17 0.01 296.26 4 2.25 3.95 7.87 8.47 0.30 0.02 296.27 5 2.82 5.07 12.02 12.94 0.46 0.05 296.30 6 3.38 6.20 16.92 18.22 0.65 0.10 296.35 7 3.95 7.33 22.52 24.25 0.86 0.18 296.43 8 4.51 8.46 28.77 30.97 1.10 0.29 296.54 9 5.07 9.58 35.61 38.35 1.37 0.45 296.70 10 5.64 10.71 43.32 46.32 1.50 0.54 296.79 11 5.36 10.99 51.20 54.32 1.56 0.58 296.83 12 5.07 10.43 58.41 61.63 1.61 0.62 296.87 13 4.79 9.86 64.96 68.27 1.66 0.66 296.91 14 4.51 9.30 70.86 74.26 1.70 0.69 296.94 15 4.23 8.74 76.12 79.59 1.74 0.72 296.97 16 3.95 8.17 80.74 84.29 1.77 0.75 297.00 17 3.66 7.61 84.77 88.35 1.79 0.77 297.02 18 3.38 7.05 88.20 91.82 1.81 0.78 297.03 19 3.10 6.48 91.04 94.68 1.82 0.79 297.04 20 2.82 5.92 93.30 96.96 1.83 0.80 297.05 21 2.54 5.36 94.98 98.66 1.84 0.81 297.06 22 2.25 4.79 96.08 99.77 1.84 0.81 297.06 23 1.97 4.23 96.62 100.31 1.85 0.81 297.06 24 1.69 3.66 96.59 100.28 1.85 0.81 297.06 25 1.41 3.10 96.01 99.69 1.84 0.81 297.06 26 1.13 2.54 94.87 98.54 1.84 0.81 297.06 27 0.85 1.97 93.18 96.84 1.83 0.80 297.05 28 0.56 1.41 90.95 94.59 1.82 0.79 297.04 29 0.28 0.85 88.18 91.79 1.81 0.78 297.03 30 0.00 0.28 84.88 88.46 1.79 0.77 297.02 Page 17 Inflow/Outflow Simulation 2-Year Storm Event 12 .00 • ' • ' • ' 10.00 • ' • .. ' • • ' ' • • ' -'O • ' c: 8 .00 • 0 0 • ' Q) ' CJ) • ... ' Q) ' Q., I -' Q) • Q) 6 .00 u.. 0 I'-, :0 . " :J I / ' () " I ' ' '""' " ~ ' ' I " 0 I ' = / " 4.00 ' ' :J ' 0 • " ' ' " ' ' " ' " ' " ' 2 .00 " 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post--• -• -• Post- Dev elopme Developme Developme Developme nt nt Outflow nt O utflow nt 'Free- Hydrograph Hydrograph With Flow ' Without Detention Detention P age 18 Inflow I Outflow Simulation 5-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 0.00 296 .25 0 .69 0 .69 0 .64 0.69 0.02 0.00 296 .25 2 1.37 2.06 2.50 2 .69 0 .10 0.00 296.25 3 2.06 3.43 5.51 5 .93 0.21 0 .01 296.26 4 2 .74 4 .80 9.57 10.30 0 .37 0.03 296.28 5 3.43 6.17 14 .62 15.74 0 .56 0 .08 296.33 6 4 .11 7 .54 20 .57 22 .15 0.79 0.15 296.40 7 4 .80 8.91 27.38 29.49 1.05 0 .26 296.51 8 5.48 10.28 34.98 37.66 1.34 0.43 296 .68 9 6.17 11 .65 43 .63 46 .63 1.50 0 .54 296.79 10 6.85 13.02 53.50 56 .65 1.57 0 .59 296 .84 11 6.51 13.37 63.57 66 .87 1.65 0 .65 296.90 12 6.17 12.68 72 .82 76.25 1.72 0 .70 296 .95 13 5 .83 11.99 81 .27 84 .82 1.78 0 .75 297.00 14 5.48 11.31 88 .95 92 .57 1.81 0 .78 297 .03 15 5.14 10.62 95.89 99 .58 1.84 0 .81 297.06 16 4 .80 9.94 102.09 105.83 1.87 0.84 297.09 17 4.46 9 .25 107.55 111 .34 1.90 0 .86 297 .11 18 4.11 8.57 112.28 116.12 1.92 0.8 8 297 .13 19 3 .77 7.88 116.29 120.16 1.94 0.90 297 .15 20 3.43 7 .20 119 .59 123.49 1.95 0 .91 297.16 21 3 .08 6.51 122.17 126.10 1.96 0 .92 297 .17 22 2.74 5 .83 124.05 128.00 1.97 0.93 297 .18 23 2.40 5 .14 125.24 129 .19 1.98 0.93 297.18 24 2 .06 4.46 125.73 129.69 1.98 0.94 297.19 25 1.71 3 .77 125.55 129 .50 1.98 0.93 297 .18 26 1.37 3 .08 124.68 128.63 1.97 0 .93 297 .18 27 1.03 2.40 123.14 127.08 1.97 0.92 297.17 28 0 .69 1.71 120.94 124.86 1.96 0 .91 297.16 29 0 .34 1.03 118.08 121 .97 1.94 0 .90 297 .15 30 0 .00 0.34 114.57 118.42 1.93 0 .89 297 .14 Page 19 u c 0 16.00 14.00 12 .00 ~ 10.00 (/) Q; 11. Q) CD LL. 8.00 0 :0 j (.) -~ 6.00 E j 0 4.00 2.00 0.00 Inflow/Outflow Simulation 5-Year Storm Event I • I I 0 5 Pre----- De velo pme nt Hydr o graph I I I ' I .. 10 ' .. ' ' ' 15 20 Time (Minutes) Post -Post- Developme Developme nt Outflow nt Outflow Hydrograph With Without Detention Detention Page 20 25 ........ 30 Post - Developme nt "Free- Flow " Inflow I Outflow Simulation 10-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 .00 296.25 1 0.77 0.77 0 .71 0.77 0 .03 0 .00 296 .25 2 1.54 2.31 2 .81 3 .02 0 .11 0 .00 296 .25 3 2.31 3 .85 6.18 6.65 0.24 0 .01 296 .26 4 3 .08 5.39 10.74 11 .56 0 .41 0 .04 296 .29 5 3 .85 6.92 16.40 17.66 0 .63 0 .09 296.34 6 4 .62 8.46 23.09 24.87 0 .89 0 .19 296.44 7 5.39 10.00 30 .73 33.10 1.18 0 .33 296 .58 8 6.15 11.54 39 .33 42.28 1.47 0 .52 296.77 9 6.92 13 .08 49.32 52.41 1.54 0.57 296 .82 10 7 .69 14.62 60 .69 63 .94 1.63 0 .63 296 .88 11 7 .31 15.00 72 .27 75 .69 1.71 0.70 296 .95 12 6.92 14.23 82 .93 86.50 1.78 0.76 297.01 13 6.54 13.46 92 .74 96.40 1.83 0 .80 297.05 14 6.15 12 .69 101 .70 105.44 1.87 0 .83 297.08 15 5 .77 11 .92 109.81 113.62 1.91 0 .87 297.12 16 5.39 11 .16 117.08 120.96 1.94 0 .90 297.15 17 5.00 10.39 123.53 127.47 1.97 0 .93 297.18 18 4 .62 9.62 129 .16 133.15 2.00 0.95 297.20 19 4.23 8.85 133.97 138.00 2.02 0.97 297.22 20 3 .85 8.08 137.97 142.05 2.04 0.99 297.24 21 3.46 7 .31 141 .18 145.28 2.05 1.00 297.25 22 3 .08 6.54 143.60 147.72 2.06 1.01 297.26 23 2 .69 5 .77 145.23 149.37 2.07 1.02 297.27 24 2.31 5 .00 146.08 150.23 2.07 1.03 297 .28 25 1.92 4.23 146.17 150.3 1 2.07 1.03 297.28 26 1.54 3.46 145.49 149.63 2.07 1.02 297.27 27 1.15 2.69 144.05 148.18 2.06 1.02 297 .27 28 0.77 1.92 141.87 145.98 2.05 1.01 297.26 29 0.38 1.15 138.94 143.02 2 .04 0 .99 297.24 30 0 .00 0 .38 135.28 139 .33 2.02 0.98 297.23 P a ge 21 Inflow/Outflow Simulation 10-Year Storm Event 16.00 ' I ' I ' ' I ' 14.00 ' I .. I ' • I ' 12.00 I ' I -I ' "O ' c I 0 ' 0 10 .00 I Q) (/) I ' .... I ' Q) 0.. I ' -' Q) I Q) ' u.. 8.00 ' 0 ' :0 ' ' ' "' ::::J ' () ' ' ' -' ' ' 3'; 6.00 ' 0 ' = I ' ' ' ::::J ' ' ' 0 ' ' ' ' ' ' . ' 4.00 ' ' ' ' , ' . ' ' ' ' 2.00 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre -----Post-Post---------Post - De velopme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph With Flow· Without Detention Det ention P age 22 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 0.00 296 .25 1 0.88 0.88 0.82 0.88 0.03 0.00 296.25 2 1.76 2.64 3.21 3.45 0 .12 0.00 296.25 3 2 .64 4 .39 7.06 7 .60 0 .27 0.02 296 .27 4 3.51 6.15 12 .27 13.21 0.47 0 .05 296.30 5 4.39 7.91 18.74 20.17 0 .72 0.12 296.37 6 5 .27 9 .67 26 .38 28.40 1.01 0.24 296.49 7 6.15 11.42 35 .10 37 .80 1.35 0.43 296.68 8 7.03 13.18 45 .25 48.28 1.51 0 .55 296.80 9 7.91 14.94 56 .99 60.19 1.60 0 .61 296 .86 10 8.79 16.69 70 .29 73.69 1.70 0 .69 296.94 11 8.35 17.13 83 .85 87.43 1.79 0 .76 297.01 12 7 .91 16.26 96.42 100.11 1.84 0 .81 297 .06 13 7.47 15.38 108.00 111 .79 1.90 0 .86 297.11 14 7 .03 14.50 118.60 122.50 1.95 0 .90 297 .15 15 6.59 13.62 128.24 132.22 1.99 0 .95 297 .20 16 6.15 12 .74 136.92 140.98 2 .03 0 .98 297 .23 17 5 .71 11 .86 144.64 148.78 2.07 1.02 297 .27 18 5.27 10 .98 151.43 155.63 2 .10 1.05 297 .30 19 4 .83 10.10 157.29 161 .54 2.12 1.08 297.33 20 4.39 9.23 162.22 166.51 2.15 1.10 297.35 21 3 .95 8 .35 166.23 170.57 2.17 1.12 297 .37 22 3 .51 7.47 169.34 173.70 2.18 1.13 297.38 23 3.08 6.59 171.55 175.93 2.19 1.15 297.40 24 2.64 5 .71 172.87 177.26 2 .20 1.15 297.40 25 2.20 4 .83 173.30 177.70 2.20 1.15 297.40 26 1.76 3 .95 172.87 177.26 2.20 1.15 297.40 27 1.32 3.08 171 .56 175.94 2.19 1.15 297.40 28 0.88 2 .20 169.40 173.76 2 .18 1.13 297.38 29 0.44 1.32 166.38 170.71 2 .17 1.12 297.37 30 0.00 0.44 162.52 166.82 2.15 1.10 297.35 Page 23 Inflow/Outflow Simulation 25-Year Storm Event 20.00 18 .00 1 1' • ' ' I ' 16.00 I .. I ' • ' • ' ' ....... 14.00 "O c • ' • ~ 0 0 Cl> en 12.00 ... Cl> 0.. -Cl> Cl> 10.00 u.. 0 ii :I u '-' 8.00 3'; 0 = :I 0 6 .00 4 .00 I I "" ' I ' . .. I I ~ ' ' I ' I ' // ~ ' ' " ' . ' ' . ' ' . . ' .. I I . ' ~ . ' ' ' I . ' ' ... . I . ' ' . ' I j . ' ' '\. .. . ' . :/ . ' --~--. ' . ' ' . . ' ' .. ' ' ', '\ ./ .· ' . : ' I';._ . ' ' . '' • l' "~ . v--',, ' __,, ', ... ', ' 2.00 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 Page 24 Inflow I Outflow Simulation 50-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 0.00 296.25 1 0.99 0 .99 0.92 0.99 0.04 0.00 296.25 2 1.99 2.98 3 .62 3.90 0.14 0.00 296.25 3 2 .98 4.97 7.98 8.59 0.31 0.02 296.27 4 3 .97 6.95 13 .87 14 .93 0 .53 0 .07 296.32 5 4.97 8.94 21.18 22.81 0 .81 0 .16 296.41 6 5 .96 10.93 29 .82 32 .10 1.14 0 .31 296.56 7 6.95 12 .91 39.78 42.73 1.47 0.52 296.77 8 7 .95 14.90 51 .56 54.68 1.56 0.58 296.83 9 8.94 16 .89 65 .12 68.44 1.66 0.66 296.91 10 9 .93 18.87 80.45 84 .00 1.77 0.75 297.00 11 9.44 19 .37 96 .14 99.82 1.84 0.81 297 .06 12 8.94 18 .38 110.69 114.51 1.91 0.87 297.12 13 8.44 17.38 124.13 128.07 1.97 0 .93 297.18 14 7 .95 16 .39 136.46 140.52 2.03 0.98 297 .23 15 7.45 15.40 147.69 151 .85 2 .08 1.03 297 .28 16 6.95 14.40 157.84 162.09 2 .13 1.08 297.33 17 6.46 13.41 166.91 171.25 2 .17 1.12 297.37 18 5 .96 12.42 174.91 179.33 2.21 1.16 297.41 19 5.46 11.42 181 .86 186.34 2.24 1.20 297.45 20 4.97 10.43 187.76 192.29 2.26 1.22 297.47 21 4.47 9.44 192 .62 197.20 2.29 1.25 297.50 22 3.97 8.44 196.45 201.06 2.30 1.27 297.52 23 3.48 7.45 199.27 203.90 2.32 1.28 297.53 24 2 .98 6.46 201 .07 205 .72 2.33 1.29 297.54 25 2.48 5.46 201 .88 206 .54 2.33 1.30 297.55 26 1.99 4.47 201.69 206 .35 2.33 1.29 297.54 27 1.49 3.48 200.52 205 .16 2.32 1.29 297.54 28 0.99 2.48 198.37 203.00 2.31 1.28 297.53 29 0 .50 1.49 195.26 199 .86 2.30 1.26 297.51 30 0 .00 0 .50 191 .20 195.76 2.28 1.24 297.49 Page 25 -"O c: 0 0 Q) 25 .00 20.00 (/) 15.00 a; 0.. Qi Q) u.. 0 :a :J (.) ; 10.00 0 = :J 0 5.00 0.00 Inflow/Outflow Simulation 50-Year Storm Event 0 5 Pre-- Developme nt Hydrograph -- I I - I ... I " I " I " ... ... ... ... 10 15 20 25 Time (Minutes) Post-Post------·-- De velopme Developme nt Outflow nt Outflow Hydrograph With With out Detention Detention Page 26 30 Post- Developme nt "Free- Flow" 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 0.00 296 .25 1 1.04 1.04 0.96 1.04 0.04 0.00 296.25 2 2 .07 3.11 3 .78 4.07 0.15 0 .01 296.26 3 3 .11 5 .19 8.33 8.97 0 .32 0.02 296.27 4 4.15 7.26 14.48 15.59 0.56 0.07 296.32 5 5.19 9 .33 22 .11 23 .81 0.85 0.17 296.42 6 6.22 11.41 31 .13 33 .52 1.20 0 .34 296.59 7 7 .26 13.48 41 .64 44.61 1.49 0.53 296.78 8 8.30 15.56 54 .04 57 .19 1.58 0 .59 296.84 9 9.33 17.63 68 .30 71 .67 1.68 0 .68 296.93 10 10.37 19.70 84.42 88.00 1.79 0.76 297.01 11 9 .85 20.22 100.92 104.65 1.87 0.83 297.08 12 9.33 19.19 116.23 120.10 1.94 0.89 297 .14 13 8 .81 18.15 130.38 134.38 2 .00 0.96 297.21 14 8.30 17 .11 143.37 147.49 2.06 1.0 1 297.26 15 7.78 16 .07 155.21 159.44 2.12 1.07 297.32 16 7.26 15 .04 165.92 170.25 2.16 1.12 297.37 17 6.74 14.00 175 .50 179.92 2.21 1.16 297.41 18 6.22 12.96 183.97 188.46 2.25 1.21 297.46 19 5 .70 11 .93 191.33 195.89 2 .28 1.24 297.49 20 5 .19 10.89 197.60 202.22 2.31 1.27 297 .52 21 4.67 9.85 202 .78 207.45 2 .33 1.30 297.55 22 4.15 8.81 206 .89 211.60 2 .35 1.32 297 .57 23 3 .63 7 .78 209.94 214 .67 2.37 1.34 297.59 24 3 .11 6.74 211 .93 216 .68 2 .38 1.35 297 .60 25 2.59 5 .70 212 .87 217.63 2.38 1.35 297 .60 26 2.07 4.67 212.78 217.54 2.38 1.35 297 .60 27 1.56 3.63 211.66 216.41 2.37 1.35 297.60 28 1.04 2.59 209 .52 214.25 2.36 1.34 297.59 29 0 .52 1.56 206 .37 211.08 2.35 1.32 297.57 30 0 .00 0 .52 202 .23 206 .89 2 .33 1.3 0 297 .55 Page 27 Inflow/Outflow Simulation 100-Year Storm Event 25.00 I ' 20.00 ... I ' ' I ' I ' ...... I ' "O I ' c 0 I ' 0 G> I c.n 15.00 ' .... ' G> I ' Q. -I ' G> I ' G> u.. I ' 0 I ' :0 ' j () ' ' ' _, 10.00 ~ I ' ' ' ' 0 . ' = . ' ' ' j • . ' 0 I ' ' ' I ' ' ' ' ' 5.00 ' . ' ' ' 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 P age 28 9 .00 8 .00 7.00 ~ 6.00 c 0 0 Q) (I) a:; Q. 5.00 'i Q) ..... 0 :0 j 4 .00 u -3:: 0 =§ 0 3.00 2.00 1.00 0.00 0 Inflow/Outflow Simulation 2-Year Storm Event 5 10 15 20 25 30 Time (Minutes) Pr e-Development Hydrograph ----Total Po st-Develo pment Hydrograph Page 29 Inflow/Outflow Simulation 5-Year Storm Event 12 .00 10 .00 -8.00 "O c 0 0 Q) (I) ... Q) Q.. -Q) Q) 6.00 u.. 0 :.0 ::::J (.) ...... ~ 0 :;: ::::J 0 4.00 2.00 0.00 0 5 10 15 20 25 30 Time (Minutes) ----Pre-Development Hydrograph ----Total Po st-Development Hydrograph Page 30 Inflow/Outflow Simulation 10-Year Storm Event 12 .00 10.00 " 8 .00 "O c 0 0 G> Cl) ... G> Q. -G> G> 6 .00 LL 0 :0 J (.) ._, ~ 0 E J 0 4.00 2.00 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Post-Development Hydrograph Page 3 1 Inflow/Outflow Simulation 25-Year Storm Event 14 .00 12.00 10.00 ......... "tJ c 0 0 G> V) ... 8.00 G> 0.. -G> G> ~ 0 :0 ::::i (.) 6.00 ......... ~ 0 E ::::i 0 4.00 2.00 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Tota l Post-Development Hydrograph Page 32 Inflow/Outflow Simulation 50-Year Storm Event 16.00 14 .00 12.00 ,..... "O c 0 10 .00 0 Q) <I) ... Q) Q. -Q) Q) 8.00 LL. 0 :0 :J () """ ~ 0 6.00 E :J 0 4.00 2 .00 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pr e -Devel o pment Hydrograph ----To t a l Post-Development Hydrograph Page 33 Inflow/Outflow Simulation 100-Year Storm Event 16.00 14.00 12 .00 ,... "'O c 0 10.00 0 Q) V> -Q) 0.. -Q) Q) 8.00 u.. 0 :Ii :J u ....., ~ 0 6.00 E :J 0 4.00 2.00 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre -Developm e nt Hydrograph ---•Tota l Post-Development Hydrograph Page 34 Detention Pond Storage Volumes as Percent of Maximum Volume 100% 90% 80% 70% G> E :::> 0 60% > E :::> E ')( 50% 0 ::: 0 -40% c G> 0 ... G> iCI.. 30% 20% 10% 0% 2-year 5-year 10-year 25-year 50-year 100-year Design Storm Storm Depth Storm Elevation 297.28 297 .55 297 .60 Storm Volume 2861 3611 4168 4948 5818 6166 Maximum Capacity 12148 12148 12148 12148 12148 12148 Percent of Capacity 24 % 30 % 34% 41% 48% 51% P a ge 35 April 15, 1996 City of College Station City Engineer 110 1 Texas Avenue South College Station , Texas 77840 Dear City Engineer: RECEIVED APR 1 7 1996 I am the owner of approximately twenty two acres of land located on Highway 6 between Graham road and Barron road. The land is located adjacent to a series of storage buildings being constructed by Kenneth Neatherlin of Neatherlin homes . The property is within the city limits. I am concerned about the elevation used in the construction of the new storage facility. As you may know, the ground level was raised, and the new elevati.on is now several feet above my adjacent property. Specifically, I am concerned about the drainage caused by this new elevation . I would like this letter entered into any official construction and/or city records documenting my concern. in addition , i wouid l ike a wr itten resp onse to answer my concerns on this matter. If you have any further questions regarding this letter, or my concern , please contact me at 776-4350. Sincerely, ,~U~ Peyton Waller ~\5 CITY OF COi .I .EGE STATION Post Office Box 9960 1101 Texas Avenue September 14, 1995 College Station, Texas 77842-9960 ,.. ~ ( 409) 764-3500 '#' \) ~ Mr. Don Garrett Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77805 \~ .. Y /~~ Dear Mr. Garrett: Enclosed is the drainage computation for the Neatherlin Self Storage Complex. It is being returned without review because it does not include information required for a drainage report by the City of College Station's Drainage Policy. It is not sufficient to provide computer printouts, hyrdographs, and charts in a report form and expect the C!o/'s Engineering Department to research all other information itself · Future reports on this and other development applications will also be returned unreviewed until they are complete. Kent Laza City Engineer enclosure: Drainage Computations cc: Kenneth Neatherlin Shirley Volk _ Veronica Morgan ·. ·- Home of Texas A&M University E i'I G t i'I EE Rt i'I G CONSULTING ENGINEERING & LAND SURVEYING 4444 CARTER CREEK PKWY, SUITE 108 BRYAN, TEXAS 77802 14091846-2688 14091 846-3094 October 14, 1996 The Legal Department City of College Station College Station , Texas 77840 To Whom It May Concern : ;JEATl-h-2c..1A.J l::£U. ~'ie.rn 1T As shown on the attached plat are the 20 ' City of College Station connects (584 /536), the 10' GTE Telephone Easement (413 /793) and the onsite 5 ' of a 20' wide GTE Easement (666 /317) and the City of College Station Electric Easement (633 /598). Some of the proposed easements will cross over but will not occupy these easements. The easements recorded in Volume 215 page 583, Volume 670 383 and Volume 48 9 page 406 do not cross this property . 255 page 587 and Volume 98 easements . J t .. TO: FROM: RE: DATE: CITY OF COLLEGE STATION LEGAL DEPARTMENT POST OFFICE BOX 9960 1101 TEXAS AVENUE COLLEGE STATION, TEXAS 77842-9960 (409) 764 -3507 MEMORANDUM Steve Homeyer, Project Manager/Engineering Department Jan Schwartz, Legal Assistant ~ J _K. Development (Neatherlin) ~ement November 11, 1996 Attached hereto for your file are copies of the executed and recorded Utility Easements on the Neatherlin Storage Buildings. :JS Attachment