HomeMy WebLinkAboutDrainage ReportDrainage Report
for
Castlegate Subdivision -Section 9
Victoria A venue
Castlegate Drive Extension
College Station, Texas
August 2002
NOTE: This report REPLACES the February 2002 report.
De vejgper_:·.
Greens Prairie Investors, Ltd.
By Greens Prairie Associates, LLC
4490 Castlegate Drive
College Station, Texas 7784 5
(979) 690-7250
Prepared&
TEXCON General Contractors
1707 Graham Road
Coll ege Station. Tex as 77845
(979) 690--771 J
CERTIFICATION
I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this
RE VISED report for the drainage design for the Castlegate Subdivision -Section 9, Victoria
A venue, & Castlegate Drive Extension, was prepared by me in accordance with the provisions
of the City of College Station Drainage Policy and Design Standards for the owners hereof.
Ginger C f;o, P .E.
TABLE OF CONTENTS
Revised DRAINAGE REPORT
CASTLEGATE SUBDIVISION -SECTION 9,
VICTORIA AVENUE, CASTLEGATE DRIVE EXTENSION
CERTIFICATION ................................................................................................................................................................. 1
TABLE OF CONTENTS ....................................................................................................................................................... 2
LIST OF TABLES .................................................................................................................................................................. 3
INTRODUCTION .................................................................................................................................................................. 4
GENERAL LOCATION AND DESCRIPTION ................................................................................................................. 4
FLOOD HAZARD INFORMATION ................................................................................................................................... 4
DEVELOPMENT DRAINAGE PATTERNS ...................................................................................................................... 4
DRAINAGE DESIGN CRITERIA ....................................................................................................................................... 5
STORM WATER RUNOFF DETERMINATION .............................................................................................................. 5
DETENTION FACILITY DESIGN ..................................................................................................................................... 8
STORM SEWER DESIGN .................................................................................................................................................... 8
CUL VERT DESIGN .............................................................................................................................................................. 9
FEMA FLOODPLAIN IMPACTS ..................................................................................................................................... 10
CONCLUSIONS ................................................................................................................................................................... 11
APPENDIX A ....................................................................................................................................................................... 12
Storm Sewer ftllet Design Calculations
APPENDIX B ........................................................................................................................................................................ 14
Storm Sewer Pipe Design Calculations
APPENDIX C ....................................................................................................................................................................... 35
Temporary Drainage Channel Caleulalions -REMOVED
APPENDIX D ....................................................................................................................................................................... 36
Culvert Design Calculations
EXHIBIT A ........................................................................................................................................................................... 43
Of/site Infrastructure Plan for Castlegate Subdivision
EXHIBIT B ........................................................................................................................................................................... 45
Post-Development Drainage Area Map -Culvert Design
EXHIBIT C ........................................................................................................................................................................... 47
Post-Developme11t Drainage Area Map -Storm Sewer Design
2
LIST OFT ABLES
TABLE l -Rainfall Intensity Calculations .............................................................................................. 6
TABLE 2 -Post-Development Runoff Information -Storm Sewer Design ........................................... 7
TABLE 3 -Post-Development Runoff Information -Storm Sewer Design, Castlegate Drive .............. 7
TABLE 4 -Culvert No. l Design Data .................................................................................................... 9
TABLE 5 -Culvert No. 2 Design Data .................................................................................................... 9
TABLE 6 -Watershed Time of Concentration Data ............................................................................. 10
TABLE 7 -Summary of Water Surface Elevations ............................................................................... 11
3
Revised DRAINAGE REPORT
CASTLEGATE SUBDIVISION -SECTION 9,
VICTORIA AVENUE, CASTLEGATE DRIVE EXTENSION
INTRODUCTION
The purpose of this revised report is to provide the hydrological effects of the construction of
the Castlegate Subdivision -Section 9, Victoria Avenue, & Castlegate Drive Extension, and to
verify that the proposed storm drainage system meets the requirements set forth by the City of
College Station Drainage Policy and Design Standards.
GENERAL LOCATION AND DESCRIPTION
The project is located on a portion of a 111.46 acre tract located west of State Highway 6 along
the north side of Greens Prairie Road in College Station, Texas. This report addresses Section
9 of this subdivision, which is made up of 19.36 acres, as well as Victoria Avenue and the
extension of Castlegate Drive. The site is wooded in the Castlegate Drive area with the
vegetation primarily consisting of oak trees and yaupons. The Victoria Avenue and Section 9
areas are pastureland with approximately 30% of the area wooded. The existing ground
elevations range from elevation 310 to elevation 334. The general location of the project site is
shown on the vicinity map in Exhibit B.
FLOOD HAZARD INFORMATION
The project site is located in the Spring Creek branch of the Lick Creek Drainage Basin. The
site is located in a Zone X Area according to the Flood Insurance Rate Map prepared by the
Federal Emergency Management Agency (FEMA) for Brazos County, Texas and incorporated
areas dated February 9, 2000, panel number 48041C0205-D. Zone X Areas are determined to
be outside of the 500-year floodplain. LJA Engineering & Surveying, Inc. submitted a Request
for Conditional Letter of Map Revision (CLO MR) to FEMA to outline a proposed 100-year
floodplain area. This CLOMR No. 00-06-844R was approved by FEMA on 9/8/2000. The
proposed floodplain area does not affect Section 9, however, a portion of the Victoria Avenue
right-of-way lies within the floodplain and Castlegate Drive passes through the floodplain.
DEVELOPMENT DRAINAGE PATTERNS
Prior to development, the storm water runoff along the Castlegate Drive extension flows toward
Spring Creek or the small tributary of Spring Creek. For Section 9 and Victoria Avenue, the
runoff flows in an easterly direction until it enters Spring Creek. Ultimately, the runoff flows
in Spring Creek north to the proposed regional detention facility. Refer to the Offsite
Infrastructure Plan in Exhibit A for the location of this proposed detention facility.
4
DRAINAGE DESIGN CRITERIA
The design parameters for th e storm sewer are as fo ll ows:
• The Rational Method is utilized to determine peak storm water runoff rates for the storm
sewer design. HEC-1 is used for the culvert design.
• Design Storm Frequency
Storm Sewer system
Culverts
• Runoff Coefficients
Pre-development
l 0 and 100-year storm events
25 and l 00-year storm events
Post-development (single family residential)
• Curve Numbers -CN
c = 0.30
c = 0.55
Refer to Appendix D for Curve Number calculations based on the soil
classification and land use.
• Rainfall Intensity values for Brazos County for a minimum time of concentration of 10
minutes can be found in Table l. Where a longer time of concentration was necessary, it is
noted in the respective table, and the intensities are calculated with the higher values where
required.
• Time of Concentration, 4: -Due to the small sizes of the drainage areas, the calculated
times of concentration, 4;, are less than 10 minutes. Therefore, a minimum tc of 10 minutes
is used in most cases to determine the rainfall intensity values. Where a longer time of
concentration was necessary, it is noted and used accordingly.
STORM WATER RUNOFF DETERMINATION
The peak runoff values were determined in accordance with the criteria presented in the
previous section for the 5, 10, 25, 50, and 100-year storm events. The runoff coefficients are
based on the future development of this tract. The drainage areas for post-development are
shown on Exhibits Band C. Exhibit B shows the post-development drainage areas for the
design of Culvert No. l and No. 2. Due to the size of the watershed draining to these
structures, the HEC-1 program was used to calculate the runoff. Exhibit B also shows drainage
areas downstream of this project. These areas will be used in determining the floodplain
boWldaries for this area. This information will be provided in a subsequent report submitted
with either Castlegate Section 7 or Section 8. Exhibit C shows the post-development drainage
areas for the storm sewer design. Post-development runoff conditions for the storm sewer
design are summarized in Table 2, and a summary of the post-development runoff conditions
used for the storm design for Castl egate Dri ve can be found in Table 3.
5
TABLE 1 -Rainfall Intensity Calculations
Rainfall Intensity Values (in/hr)
Storm t.:=
Event 10 min
Is 7.693
110 8.635
l2s 9.861
lso 11 .148
1100 11 .639
Brazos County:
5 t'.ear storm 10 t'.ear storm
b = 76 b = 80
d = 8.5 d = 8.5
e = 0.785 e = 0.763
I = b I (tc+d)e
I = Rainfall Intensity (in/hr)
tc = U(V*60)
tc =Time of concentration (min)
L = Length (ft)
V = Velocity (ft/sec)
25 t'.ear storm 50 t'.ear storm 100 t'.ear storm
b = 89 b = 98 b = 96
d = 8.5 d = 8.5 d = 8.0
e = 0.754 e = 0.745 e = 0.730
(Data taken from State Department of Highwat'.S and Public Transportation Ht'.draulic Manual . page 2-16)
6
TABLE 2 -Pos t-Development Runoff I nfo rmation -Storm Sewer Design
Area c 5 year storm 10 year storm 25 year storm 50 year storm 100 year storn
tc Area # (acres) Is Os '10 0 10 l2s 0 2s lso Oso 1100 C1 C2 C rotal A1 A2 Total (min) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in/hr)
9-1 0.23 0.23 0.55 0.55 10 7.693 0.97 8.635 1.09 9.861 1.25 11 .148 1.41 11.639 --9-2 0.17 0.17 0.55 0.55 10 7.693 0.72 8.635 0.81 9.861 0.92 11 .148 1.04 11 .639
~ -------9-3 0.22 0.22 0.55 0.55 10 7.693 0.93 8.635 1.04 9.861 1.19 11 .148 1.35 11 .639 --9-4 0.18 0.18 0.55 0.55 10 7.693 0.76 8.635 0.85 9.861 0.98 11 .148 1.10 11 .639
9-5 0.15 0.15 0.55 _Q 55 10 7.693 0.63 8.635 0.71 9.861 0.81 11 .148 0.92 11 .639 --I---~-9-6 0.47 0.47 0.55 0.55 10 7.693 1.99 8.635 2.23 9.861 2.55 11 .148 2.88 11 .639
9-7 0.44 0.44 0.55 0.55 10 7.693 1.86 8.635 2.09 9.861 2.39 11 .148 2.70 11 .639
9-8 0.56 0.56 0.55 0.55 10 7.693 2.37 8.635 2.66 9.861 3.04 11 .148 3.43 11 .639 -------------------· ---9-9 0.50
9-10 0.10
9-11 0.11
9-12 0.07
9-13 0.12
9-14 1.69 0.10
9-15 1.53 0.20
9-16 1.66 0.30
9-17 1.49 0.39
9-18 1.77 0.33
9-19 1.75 1.01
9-20 1.95 0.56
9-21 1.24 2.74
9-22 0.60
The Rational Method:
Q=CIA
Q = Flow (cfs)
A = Area (acres)
C = Runoff Coeff.
0.50 0.55 0.55 10 7.693
0.10 0.55 0.55 10 7.693
0.11 0.55 0.55 10 7.693
0.07 0.55 0.55 10 7.693
0.12 0.55 0.55 10 7.693
1.79 0.55 0.3 0.54 10 7.693
1.73 0.55 0.3 0.52 10 7.693
1.96 0.55 0.3 0.51 10 7.693
1.88 0.55 0.3 0.50 10 7.693
2.10 0.55 0.3 0.51 10 7.693
2.76 0.55 0.3 0.46 10 7.693
2.51 0.55 0.3 0.49 10 7.693
3.98 0.55 0.3 0.38 10 7.693
0.60 0.55 0.55 10 7.693
I = b I (tc+dje
le= Time of concentration (min )
I = Rainfall Intensity (in/hr)
Brazos County:
5 y_ear storm 10 y_ear storm 25 y_ear storm
b = 76 b = 80 b = 89
d = 8.5 d = 8.5 d = 8.5
e = 0.79 e = 0.76 e = 0.75
2.12
0.42
0.47
0.30
0.51
7.38
6.94
7.72
7.20
8.25
9.74
9.54
11.57
2.54
8.635 2.37
8.635 0.47
8.635 0.52
8.635 0.33
8.635 0.57
8.635 8.28
8.635 7.78
8.635 8.66
8.635 8.09
8.635 9.26
8.635 10.93
8.635 10.71
8.635 12.99
8.635 2.85
tc = L/(V*60)
L = Length (ft
9.861 2.71 11 .148
9.861 0.54 11 .148
9.861 0.60 11.148
9.861 0.38 11.148
9.861 0.65 11.148
9.861 9.46 11.148
9.861 8.89 11 .148
9.861 9.89 11.148
9.861 9.24 11.148
9.861 10.58 11.148
9.861 12.48 11 .148
9.861 12.23 11.148
9.861 14.83 11 .148
9.861 3.25 11 .148
V =Velocity (fUsec)
50 y_ear storm 100 y_ear storm
b = 98 b = 96
d = 8.5 d = 8.0
e = 0.745 e = 0.730
3.07 11.639
0.61 11 .639
0.67 11 .639
0.43 11 .639
0.74 11.639
10.70 11.639
10.05 11.639
11 .18 11.639
10.44 11.639
11 .96 11.639
14.11 11.639
13.83 11.639 ---16.77 11 .639
3.68 11.639
TABLE 3 -Post-Development Runoff Information -Storm Sewer Design, Castlegate Drive
Area le
5 year storm 10 year storm 25 year storm 50 year storm 100 year storm
Area# c Is Os 110 0 10 l2s 025 150 Oso 1100 0 100
(acres) (min) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs)
1 0.88 0.55 10 7.693 3.72 8.635 4.18 9.861 4.77 11 .148 5.40 11 .639 5.63
2 3.40 0.55 10 7.693 14.39 8.635 16.15 9.861 18.44 11 .148 20.85 11.639 21.77 ----·--------------5 3.16 0.50 10 7.693 12.15 8.635 13.64 9.861 15.58 11.148 17.61 11 .639 18.39 -------------------------------
6 3.44 0.55 10 7.693 14.55 8.635 16.34 9.861 18.66 11.148 21 .09 11 .639 22.02 -----------------7 0.91 0.55 10 7.693 3.85 8.635 4.32 9.861 4.94 11 .148 5.58 11.639 5.83
7
0100
(cfs)
1.47 ,....__
1.09
1.41
1.15
0.96 c------3.01
2.82
3.58 -3.20
0.64
0.70 ,_
0.45
0.77
~
11.17
10.49
11.67 ,___
10.90
12.48
14.73
14.44 --17.51
3.84
DETENTION FACILITY DESIGN
The detention facility handling the runoff from this site will be a regional facility designed by
LJA Engineering & Surveying, Inc. Refer to the Offsite Infrastructure Plan in Exhibit A for the
location of this proposed detention facility. The runoff from this project flows into existing
drainages and then into Spring Creek. The detention facility is located adjacent to Spring
Creek prior to Spring Creek entering the State Highway 6 right-of-way. The LIA report
proposed a weir structure in the Spring Creek tributary downstream of Cast legate Drive to also
provide detention storage. The existing pond upstream of Castle gate Drive is proposed to
remain and is currently being modified as shown on the attached Pond Design drawing, Sheet l
of 1. The pond will function as a detention pond and possibly eliminate the need for the
proposed weir structure.
STORM SEWER DESIGN
The storm sewer piping for this project has been selected to be Reinforced Concrete Pipe
(RCP) meeting the requirements of ASTM C-76, Class m pipe. The curb inlets and junction
boxes will be cast-in-place concrete.
Appendix A presents a summary of the storm sewer inlet design parameters and calculations.
The inlets were designed based on a 10-year design storm. As per College Station guidelines,
the capacities of inlets in sump were reduced by 10% to allow for clogging.
[nlets for the residential streets were located to maintain a gutter flow depth of 5" or less, and
inlets for Victoria Avenue and Castlegate Drive were located to maintain a gutter flow depth of
7" or less. These design depths will prevent the spread of water from reaching the crown of the
road for the l 0-year storm event. The runoff intercepted by the proposed storm sewer inlets
was calculated using the following equations. The depth of flow in the gutter was determined
by using the Straight Crown Flow equation. The flow intercepted by Inlets 901-903 & 914-916
was calculated by using the Capacity of Inlets On Grade equation. The capacities for the inlets
in sumps (Inlets 904-913) were calculated using the Inlets in Sumps, Weir Flow equation with a
maximum allowable depth of 7" (5 " gutter flow plus 2" gutter depression). These equations
and the resulting data are summarized in Appendix A.
Appendix B presents a summary of the storm sewer pipe design parameters and calculations.
All pipes are 18" in diameter or larger. For pipes with l 8" and 24" diameters, the cross-
sectional area is reduced by 25%, as per College Station requirements. A summary of how this
was achieved is shown in Appendix B as well. The pipes for the storm sewer system were
designed based on the 10-year stom1 event, and most will also pass the 100-year storm event
without any headwater. Based on the depth of flow in the street detem1ined for the 100-year
storm event, this runoff will either be contained within the street right-of-way until it enters the
stom1 sewer system, or, in the case of Pipes 6 & 13 , the overtopping will spill into the pond in
the park area along the street. As required by College Station, the velocity of flow in the storm
sewer pipe system is not lower than 2.5 feet per second, and it does not exceed 15 feet per
second. As the data shows, even during low flow conditions, the velocity in the pipes will
exceed 2.5 feet per second and prevent sediment build-up in the pipes. The maximum flow in
the storm sewer pipe system will occur in Pipe No. 13 . The maximum velocity for th e pipe
system in this development will be 13.1 feet per second and will occur in Pipe o. 13.
8
Appendi x B contain s a summary of the Manning pipe calculations as well as fl ow diagrams
mapping the flo ws through the storm sewer system for the l 0 and l 00-year events.
Storm sewer Pipes l 0 & l l and Inlet 909 wi II be constructed as part of the Section 9
constructio n even though portions of these structu res are in Section I 0. Thi s construction wi ll
eliminate the construction and future reclamation of the temporary drainage channel. Silt fence
will be installed around Inlet 909 to prevent sediment from entering th e inl et opening until the
extension of Norham Drive is completed.
CUL VERT DESIGN
The culverts for this project have been selected to be Reinforced Concrete Precast Box Sections
meeting the requirements of AS TM C-789. The headwalls at either end of the culverts will be
cast-in-place concrete. Data used for designing Culvert Nos. 1 & 2 can be found in Tables 4 &
5, respectively. The time of concentration data and calculations are in Table 6.
TABLE 4 - Culve rt No. 1 Des ign Data
Time of Drainage Area Concentration, Tc SCS Curve Number, CN
No. (acres) (sq. mi.)
2 3.40 0.0053
4 29.85 0.0466
HEC-1 Peak Runoff values:
Q25 = 199 cfs
Q100 = 239 cfs
(min) (hrs)
5.7 0.095
9.8 0.163
Refer to Table 6 for Time of
Concentration Calculations
1 -8 ' (span) x 4 ' (rise) box culvert with headwalls & wi11gwalls
Length= 67', Slope= 1%
TABLE 5 - Culve rt No. 2 Design Data
Time of
87.4
86.1
Drainage Area Concentration, Tc SCS Curve Number, CN
No. (acres) (sq. mi.)
5 3.44 0.0054
6 3.16 0.0049
7 0.91 0.0014
8 16.27 0.0254
9 135.58 0.2118
10 22.63 0.0354
HEC-1 Peak Runoff values :
Q25 = 507 cfs
Q100 = 670 cfs
(min) (hrs)
8.2 0.137
7.6 0.126
3.8 0.063
12.0 0.200
22.3 0.371
12.4 0.207
Refer to Table 6 for Time of
Concentration Calculations
2 -8' (<;pan) x 4 ' (rise) box culverts with headwalls & willgwalls
l ength = 65', Slope= 0.6%
85.7
85.8
88.8
86.4
79.6
91.0
TABLE 6 -Watershed Time of Concentration Data
Drainage Area Overland Flow Upland Gully Flow Channel Flow nmeof scs
Length Slope Velocity Travel Time Length Slope Velocity Travel Time Length Slope Velocity Travel Time Concentration, Tc Lag
No. (acres) (sq. mi.) (ft) (%) (fps) (min) (ft) (%) (fps) (min) (ft) (%) (fps) (min) (min) (hrs) (hrs)
1 O.BB 0.0014 950 2.1% 5.5 2.9 2.9 0.04B 0.029
2 3.40 0.0053 300 3.5% 1.3 3.B 700 2.6% 6.2 1.9 5.7 0.095 0.057
3 16.62 0.0260 250 2.4% 1.1 3.B 1700 0.5% 3.3 B.6 0.143 f->---700 1.7% 6.2 1.9 14.3 0.23B
4 29.85 0.0466 300 2.0% 1.0 5.0 550 2.4% 3.1 3.0 700 1.7% 6.2 1.9 9.8 0.164 0.098
5 3.44 0.0054 300 3.0% 1.2 4.2 420 2.1% 2.9 2.4 300 0.7% 3.1 1.6 8.2 0.137 0.082
6 3.16 0.0049 300 3.0% 1.3 3.8 420 1.9% 2.8 2.5 320 1.3% 4.3 1.2 7.6 0.126 0.076
7 0.91 0.0014 700 0.6% 3.1 3.8 3.8 0.063 0.03B
8 16.27 0.0254 300 1.0% 0.7 7.1 750 2.5% 3.2 3.9 BOO 13.9 1.0 12.0 0.200 0.120
9 135.5B 0.2118 300 2.7% 1.2 4.2 1750 1.6% 2.5 11.7 1250 0.6% 3.B 5.5 0.223 BOO 13.9 1.0 22.3 0.371
10 22.63 0.0354 300 1.7% 0.9 5.6 1100 2.4% 3.1 5.9 BOO 13.9 1.0 12.4 0.207 0.124
NOTES:
1. Overland Flow Travel Time computed as follows:
TI= U(60.V) where V =flow velocity in fps based on land slope and Figure 15.2 (short grass pasture overland flow). SCS NEH-4
2. Upland Gully Flow Travel Time computed as follows:
TT= U(60'V) where V =flow velocity in fps based on land slope and Figure 15.2 (small upland gullies). SCS NEH-4
3. Channel Flow Travel Time computed using design channel velocity or. If no design velocity available. as follows:
n = U(60.V) where V = (1.49 • Rm· S 112) I n
n =roughness coefficient = 0.05 (estimate for small channels)
4. Time of Concentration computed as follows:
TC= summation of travel times computed in Steps 1, 2 & 3 above.
Culvert No. Top of Road Headwater Elevations
Elevation, (ft) 025 (ft) 0100 (ft)
1 314.00 310.00 310.93
2 307.80 306.09 307.90
The culverts were designed to pass the runoff from the 25-year storm event with the upstream
headwater at least l foot below the street top of curb. However, Culvert No. l also passes the
100-year storm runoff without overtopping the road. Culvert No. 2 has a headwater elevation
of 307.9 for the l 00-year storm event, which is 0.1' higher than the road elevation. This depth
overtopping the roadway will not affect the traffic using the roadway. Culvert No. 2 was
designed assuming that the existing pond was modified and does have an impact on the peak
runoff. The 25-year exit velocity for Culvert No. l is 13.4 fps, and the 25-year exit velocity for
Culvert No. 2 is 12.1 fps. The downstream headwalls will have energy dissipaters. Refer to
Appendix D for the culvert calculator data for the culvert design.
FEMA FLOODPLAIN IMPACTS
The peak runoff values from the HEC-1 program using the post-development condition data
presented in this report were input into the HEC-RAS computer model used for the FEMA
LOMR for this area. Tab le 7 shows a summary of the computed water surface pro fi Jes for the
stream tributaries which flow through Culvert Nos. I & 2.
The increased runoff for the developed condition is due not only to the increased runoff
coefficients, but also to the decrease in the lag time used in the HEC-1 program. The runoff
data for the LOMR completed by LJA Engineering was computed using a lag time detem1ined
by the Lag Method per TR-55. The developed condition runoff data is computed using the
upland, or velocity, method to compute the lag time. Thi s method is more conservative and
10
scs
Curve
Number
BB.4
B7.4
79.6
86.1
85.7
B5.8
8B.8
86.4
79.6
91 .0
TABLE 7 -Summary of Water Surface E levations
Culvert No. 1 Tributary 100-Year Storm Event
River Existing LOMR Developed Conditions Change in Water
Reach Station Q Total Water Surface Elev. Q Total Water Surface Elev. Surface Elevation
(cfs) (ft) (cfs) (ft) (ft)
A2B 2190 226.00 32306 230.00 323.07 0.01
A2B 2110 226.00 321 .39 230.00 321.40 0.01
A2B 2051 226.00 320.34 230.00 320.36 0.02
A2B 1976 226.00 318.53 230.00 318.54 0.01
A2B 1846 226.00 317 07 230.00 317.08 0.01
A2B 1669 226.00 31501 230.00 315.04 0.03
A2B 1545 226.00 312.49 230.00 312.49 0.00
A2B 1426 226.00 311.49 230.00 311 .54 0.05
A2B 1126 226.00 308.89 244.00 308.95 0.06
A28 1007 226.00 306.93 244.00 307.06 0.13
A28 723 226.00 305.13 287.00 305.37 0.24
A28 436 226.00 30 1.95 287.00 302.14 0.19
Culvert No. 2 Tributary 100-Year Storm Event
River Existing LOMR Developed Conditions Change in Water
Reach Station Q Total Water Surface Elev. Q Total Water Surface Elev. Surface Elevation
(cfs) (ft) (cfs) (ft) (ft)
A2A 28990 751.00 313.43 731 .00 313.44 0.01
A2A 27357 751 .00 309.91 824.00 310.00 0.09
A2A 27184 751 .00 308.98 824.00 308.99 0.01
A2A 27110 751 00 308.42 764.00 308.38 -0.04
A2A 26794 751.00 305.60 758.00 305.73 0.1 3
A2A 26398 751.00 303.79 921 .00 303.98 0.19
results in a lower time of concentration and lag time. This value is typically one half or less of
the Lag Method value. This will result in the HEC-1 program computing a higher peak nmoff
amount.
Even with the increased runoff, the increases in the water surface elevations for the 100-year
storm are very minor, as shown in Table 7. The impact to the limits of the floodplain will also
be minor.
CONCLUSIONS
The construction of this project wi ll significantly increase the storm water runoff from this site.
The proposed storm sewer system should adequately control the runoff and release it into
existing drainages. Also, the regional detention facility should adequately reduce the peak
post-development runoff to less than the pre-development runoff for the design storm event.
Use of the existing pond will also reduce the effects of the increased runoff in the immediate
area of this project. This wi ll prevent any impact on the properties downstream of this proj ect.
11
APPENDIX A
Storm Sewer Inlet Design Calculations
12
Cas tlegate Subdivision
Section 9
Inlet Length Calculations
Inlet#
905
906
907
.JOa ·.,;,..
909
910
911
912
913
Inlet#
902
903
901
915
916
914
Inlets In Sump 10 year storm
Length A c Q,.
(ell)
Oroi1:a1 Oro1..,..10"11. Y10-Kt~
Are1 # (1cru) (cfs) from Inlet# (els) (els) !ft) !In)
9-22 0.60 8.79 901-903 0.55 2.85 11.6-4 12.80 0.375 4.50 -g::g-o:5o -0.55 2.37 2.37 2.61 0.207 2.46
0.47 0.55 2.23 2.23 2.46 0.202 2.42
9-5 0.15 0.55 0.71 0.71 0.78 0.131 1.58
9-18 2.10 0.51 9.25 9.25 10.17 0.347 4.16
9-17 1.88 0.5 8.12 8.12 8.93 0.330 3.96
9-13 0.12 0.55 0.57 0.57 0.83 0.122 1.46 r----f------11---+----I----+----+--~~----9-12 0.07 0.55 0.33 0.33 0.37 0.100 1.20
>).16 196 051 663 8.63 9 .J') 0.338 .J.06 I---->------1-----1---·l----l---+-----1----1--9-7!' 1 -:'.' V52 7.'ii 7(7 654 0~125 390
9-11 0.11 0.55 0.52 0.52 0.57 0.118 1.42 -~---11---+----~---+-----<----lt----t---"-9-10 0.10 0.55 0.47 0.47 0.52 0.114 1.37
9-8 0.56 0.55 2.66 2.66 2.93 0.215 2.59
9-7:9-14 2.23
9-4 0.18
9-3 0.22
5 3 16
9-2 0 17
9-1 0.23
7 0.91
0.55 10.59 10.59 11.65 0.382 4.34
0.55 0.85 0.85 0.94 0.141 1.69 -1-----1-----1----1----+ ------0.55 1.04 1.04 1.15 0.152 1.82
0.3 8.19 0.00 914 8.19 9 00 0.333 4.00 1------+---I---~-0 55 0.81 0.81
0.55 1.09 0.00 916 1.09 0.5-5-l·-4-.3-2-1----1-----1--4-.3-2--1
0.89 0.140
120 0.157
-·~-------4.75 0.262
1.68
1.88
3 15
Inlets On Grade 10 year storm
Length FloW from y,, a,...,_ Oc.s-lty a.,,.. ..
Area# (ft) lin) !ft) (els) lcf•)
10' 9-20 0.409 4.90 0.70 7.02 3.60
10' -9-19 0.414 4.96 0.71 7.07 3.89
IS' --·-----9-21 0.488 5.86 0.78 11.77 1.29
15· --2-0.459 -5.50 0.70 10.53 0.92
10· ----o.Jl4 -1 3.77 0.58 5.76 -1.58
15' --·--,______
6 0.441 5.29 0.69 10.28 -1.37
Transverse tCrovvnl slooe ffVftl
for residential streets = 0.033 (Inlets 902, 903, 906-909)
for Victoria Avenue = 0.0315 (Inlets 901 , 904, 905, 910, 911)
for Castlegate Drive= 0.034 (Inlets 912-916)
Straight Crown Flow !Solved to find actual depth of flow, y):
Q = 0.56' (z/n)' s•n' y"' «> y ={QI [0.56' (z/n)' S1n)}"'
n = Roughness Coefficien1 =
S = StreeVGutter Slope (ftlft)
y = Depth of flow at inlet (ft)
Capacity of Inlets on grade:
0.018
0c = 0.7' [1/(H1 -H,)]' [H,"'-H,'n}
Oc = Flow capac11y of inlet (els)
H1 = a + y
H1 = a = gutter depression (2" Standard. 4" Recessed)
y = Depth of flow 1n approach gutter lft)
Cle.,-"'"' OcanyDYM Qb°1'P"4otll
lcf•) (els) from lnlett (cf•)
7.02 I J.60
7.07 3.89
11.77 1.29 --------10.53 0.92 -----4,18 0.00
8.91 0.92 915 0.00
z = Reciprocal of CfQINT1 slooe
for residential streets = 30
for Victoria Avenue = 32
for Castlegate Drive = 29
L,°""'Mf' ..
!ft)
11.54
2.43
14.30
0.74
iJ.51
0.82
10.91
1.56
7.41
4.46
llt)
15
15
15
15
15
100 year atorm
C100 Cc.,,.,..,.. Otou.1 OrotaMO"A.l---Yc,•-"---1
(els) (els) from Inlet• (els) (els) !ft) (In)
3.84 18.90 901-903 22.74 25.02 0.738 8.86
3.20 3.20 3.52
~ ----t-----+-3_.0_1-+_3_.3_1--1
0.96 0.96 1.06 0.439 5.27
12.47 12.47 13.71 0.689 8.27 10.94 10.94 12.03
0 77 0. 77 0.84 ---·-·----1--.,--1--,----,--l 0.45 0.45 0.49 0.200 2.40
1163 11 63 12.80 0 663 10 .JJ 10 .J.7 i I 52
0.70 0.70 0.77 I------1-----+---f---I 0.6-4 0.64 0. 70 0.213 2.56
3.58 3.58 3.94 >-·-------------1----1----14.28 14.28 15.70 0.575 6.91
1.15 1.15 1.27 0.328 3.93 1.41 1.41 1.55
11.03 5.17 914 16.20 17.82 0.563 6.76 1.09 1.09 1.20
1.47 0.00 0.659 7.91 916 1.~7 1.62 ---1----~--5.83 5.83 6.41
100 year storm
Clc:1pt-totl C1~Total y,,. a,...,_ 0-upac:My Qb'f'PUI 0c.p1 ..... ite1 <lca11yov..-
(els) (els) (ft) (in)
7.02 10.62 0.457 5.49
7.07 10.96 0.463 5.55
11.77 l-•13.06 0.546 6.55
10.53 ~ o.513' -----s:16-
4":18--0.352 4.18 4.22 ------I----8.91 8.91 0.551 6.61
Inlets In sumps, Weir Flow:
L = QI (3' y'n) «> y = (QI 3L)"'
L = Length of inlet opening (fl)
Q = Flow at inlet (els)
y = total depth of flow on inlet (ft)
max y for inlet in sump = 7" = 0. 583'
(ft) (els) (els) (els) lcf•) from Inlet•
0.75 7.52 6.80 7.52
0.78 7.57 7.20 7.57
0.85 12.70 4.90 12.70 -· 0.75 11.28 4.16 11.28
0.61 6.07 -0.44 5.63 -----0.73 11.00 1.01 11.00 4.16 915
Qb)'tH<Hal Ocapl-t<KI Ql~Total s L..c1u11
(els) (els) (els) (Ml) lft)
6.80 7.52 14.31 0.01 50 10
7.20 7.57 14.78 0.0150 10
4.90 12.70 17.60 0.0080 15 ---4.16 11.28 15.43 0.0100 15 ---0.00 5.63 5.63 0.0100 10 ---5.17 11.00 16.17 0.0075 15
APPENDIXB
Storm Sewer Pipe Design Calculations
14
City of College Station requirement to Reduce Cross-Sectional Area of 18" & 24" Pipes by 25%
Using Mannings Equation from page 48 of the College Station Drainage Policy & Design Standards Manual:
Q = 1.49/n *A * R213 * S112
Q = Flow Capacity (cfs)
18" Pipe:
Pipe size (inches) =
Wetted Perimeter WP. (ft)=
Cross-Sectional Area A, (ft2) =
Reduced Area AR, (ft2) =
Hydraulic Radius R =A/WP, (ft) =
Reduced Hydr Radius RR= AR/Wp, (ft)=
Roughness Coefficient n =
Friction Slope of Conduit S1, (ft/ft) =
Example Calculation:
Slope Flow Capacity Reduced Flow Capacity
s Q
0.005 6.91
0.006 7.57 ---------0.007 8.18
24" Pipe:
Pipe size (inches)=
Wetted Perimeter W P. (ft) =
Cross-Sectional Area A. (ft2) =
Reduced Area AR, (ft2) =
Oreduced
4.28
4.69
5.06
Hydraulic Radius R =A/WP, (ft) =
Reduced Hydr Radius RR= AR!Wp. (ft) =
Roughness Coefficient n =
Friction Slope of Conduit S1, (ft/ft) =
Example Calculation:
Slope Flow Capacily Reduced Flow Capacily
s Q Oreduced
0.005 14.89 9.22 --
0.006 16.31 10.1 ------0.007 17.61 10.9
Conclusion:
18
4.71
1.766
1.325
0.375
0.281
0.014
0.01
% Difference
Ored~Q
0.619 --------
-0.619 ---0.619
24
6.28
3.14
2.355
0.5
0.375
0.014
0.01
% Difference
Ored~Q
0.619
0.619 --0.619
-
Multiply actual Q in 18" & 24" pipes by 1.615 to reflect a 25% reduction in the
cross-sectional area called for on page 47, paragraph 5 of the College Station
Drainage Policy & Design Standards manual.
Castlegate Subdivision
Section 9
Size Inlet Outlet 1 O year storm 100 year storm Pipe# Length Slope Invert Elev Invert Elev •Actual Flow Design Flow V10 Travel Time, tno •Actual Flow Design Flow V100 Travel Time, tnoo % Full
(in) (ft) (%) (ft) (ft) (cfs) (cfs) (fps)
% Full
(sec) (min) (cfs) (cfs) (fps) (sec)
1 18 31 .6 2.00 308.21 307.58 7.02 11 .34 8.7 68.3 4 0.06 7.52 12.14 8.8 72.0 4
2 24 46.4 1.50 307.09 306.39 14.09 22.76 9.2 71 .7 5 0.08 15.09 24.37 9.3 77.6 5
4 27 124.3 0.80 306.40 305.41 25.86 7.4 81 .3 17 0.28 27.79 7.3 92.2 17 ·----5 4x2 42.0 0.35 305.36 305.21 39.87 6.2 79.8 7 0.11 53.73 6.8 99.5 6 -----
6 36 325.0 0.40 305.16 303.86 42.81 6.4 90.2 51 0.85 57.70 9.3 100.0 35 --
-------------
3 24 63.7 1.25 307.44 306.64 11 .77 19.01 8.3 68.2 8 0.13 12.70 20.51 8.4 72.4 8 --~ ----------------r--------·
---------------
7 27 31 .1 0.60 308.15 307.96 17.37 6.2 66.7 5 0.08 23.41 6.3 88.6 5
-~ --------------------
8 27 233.9 0.70 307.86 306.22 18.27 6.7 65.5 35 0.58 24.63 6.9 85.0 34 --------------~ --------------------g 2+ ~ ~ ~ ~ ~ 0,-7 ~ J ~ ~ ~ ~ J ---------
Temp Channel +9-+-,.G -Ma ~ ~ --11 36 142.4 1.50 305.89 303.75 35.66 10.6 48.3 13 0.22 48.07 11.4 57.9 12 . ·--r-----------12 36 42.1 0.70 303.65 303.36 48.91 8.3 77.5 5 0.08 65.93 9.3 100.0 5 -----13 42 263.4 0.90 302.86 300.49 93.61 10.4 88.5 25 0.42 126.19 13.1 100.0 20 --------
--------17 24 24.2 1.50 306.13 305.77 8.91 14.39 8.4 53.5 3 0.05 11 .00 17.77 8.8 61 .1 3 ----16 30 154.0 0.85 305.52 304.21 8.91 6.0 34.3 26 0.43 11 .00 6.3 38.4 24 -------15 30 237.9 0.85 304.12 302.10 8.91 6.0 34.3 40 0.66 11 .00 6.3 38.4 38
14 30 59.0 0.85 302.00 301 .50 8.91 6.0 34.3 10 0.16 11 .00 6.3 38.4 9
·These values reflect the actual flow for the 18" & 24" pipes. The design flow for these pipe sizes reflects a 25% reduction in pipe area.
(Refer to attached calculation for specific information.)
(min)
0.06
0.08
0.28
0.10
0.58
---0.13
0.08 ---
0.56 ---~
0.21
0.08
0.34 ---
0.05
0.41
0.63
0.16
Removed
Removed
Inlet 9021 7.02
J,
Pipe 1 I 7.02
J,
Inlet 9031 7.07
J,
Pipe 2 I 14.09
J,
June Box 1
J,
Pipe 4 I 25.86
J,
Inlet 904 1 14.01
J,
Box 5 I 39.87
J,
Inlet 905 1 2.94
J,
Pipe 6 I 42.81
J,
Inlet 911 I 1.89
J,
Pipe 13 j 93.61
J,
Inlet 912 1 9.00
!!Culvert 21 322 cfs II
Castlegate Subdivision
Section 9 -Pipe Flow Diagram
0 10 (cfs)
Inlet 906 1 17.37
J,
Pipe 7 I 17.37
J,
Inlet 901 j 11 .77 Inlet 907 1 0.90
J,
f-Pipe 3 I 11 . 77
Removed
Removed
Includes 16.4 cfs -+
from Inlet 908
J,
Pipe 8 I 18.27
J,
J1rns EIG1' 2
J,
~1 ~
J,
Inlet 909 1 0.99
J,
Pipe 11 I 35.66
J,
Inlet 910 1 13.25
J,
Pipe 12 I 48.91
Inlet 914 1 8.91
J,
Pipe 17 I 8.91
J,
June Box 5
J,
Pipe 16 I 8.91
J,
June Box 4
J,
Pipe 15 I 8.91
J,
June Box 3
J,
Pipe 14 I 8.91
Inlet 902 1 7.52
J,
Pipe 1 I 7.52
J,
Inlet 903 1 7.57
J,
Pipe 2 I 15.09
J,
June Box 1
J,
Pipe 4 j 27.79
J,
Inlet 904 1 25.94
J,
Box 5 j 53.73
J,
I Inlet 9051 3.97
J,
Pipe 6 I 57.70
J,
Inlet 911 j 2.56
J,
Pipe 13 I 126.19
J,
Inlet 9121 17.29
Castlegate Subdivision
Section 9 -Pipe Flow Diagram
0 100 (cfs)
Inlet 906 I 23.41
J,
Pipe 7 j 23.41
J,
lnlet901 I 12.70 Inlet 907 j 1.22
J,
~ Pipe 3 I 12.70
Removed
Removed
Includes 22.1 cfs -+
from Inlet 908
J,
Pipe 8 I 24 .63
J,
J1JAG l3QX 2
J,
~1 ~
J,
Inlet 909 j 1.34
J,
Pipe 11 ! 48.07
J,
Inlet 910! 17.86
J,
Pipe 12 I 65.93
llCulvert 21 670 cfs ll(per HEC-1 calculations)
Inlet 914 1 11 .00
J,
Pipe 17 j 11 .00
J,
June Box 5
J,
Pipe 16 I 11 .00
J,
June Box 4
J,
Pipe 15 I 11.00
J,
June Box 3
J,
Pipe 14 I 11 .00
Pipe 1 -10 Year Storm
Manning Pipe Calcu lator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
18 .0000 in
11.3400 cfs
0.0200 ft/ft
0 . 0140
,,
12.2958 in tv
1.7671 ft2
1.2861 ft2
35.0229 in
56.5487 in
8 .6926 fps
5.2881 in
68.3100 %
13.7943 cfs /
7. 8060 fps ./
Pipe 1 -100 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Circular
Depth of Flow
18.0000 in
12. 1400 cfs
0.0200 ft/ft
0.0140
12.9572 in \?
1. 7671 ft2
1.3618 ft2
Wetted Perimeter . . . . . . . . . . . . . . . . 36.4689 in
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdiv ision -Section 9,
56 .5487 in
8 .7899 fps
5 .3771 in
71 .9845 %
13 . 7943 cfs
7 .8060 fps
Victoria Avenue & Castlegate Drive Extension
College Station, Texas
Pipe 2 -10 Year Storm
Manning Pipe Calculator
Given Input Dat a :
Shape .......................... .
Solving for .................... .
Diame t er ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
24 .0000 in
22.7600 cfs
0 .0150 ft /ft
0 .0140
\
O, If
17.2053 in u
3 .1416 ft2
2.4 103 ft2
48.4675 in
75.3982 in
9.2145 fps
7.1612 in
71.6889 %
25.7276 cfs
8 .1894 fps
Pipe 2 -100 Year Storm
Manni ng Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdivision -Section 9,
Circular
Depth of Flow
24.0000 in
24.3700 cfs
0 .0150 ft/ft
0. 0140
lr. II 18 . 6224 in v\
3 .1416 ft2
2.6156 ft2
51.7296 in
75.3982 in
9.3171 fps
7 .2811 in
77 .5934 %
2 5 . 7276 cfs
8 .1894 fps
Victoria Avenue & Castlegate Drive Extension
Col lege Statio n, Texas
Pipe 3 -1 0 Year Sto r m
Mann i ng Pipe Cal culator
Given I nput Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Cir cular
Depth of Flow
24 .0000 in
19 .0100 cfs
0 .0125 ft/ft
0.0140
l(
16.3785 in lC#
3.1416 ft2
2 .2840 ft2
46 .6631 in
75.3982 in
8 .323 1 fps
7 .0484 in
68.2437 %
23.4860 cfs
7.4758 fps
Pipe 3 -100 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdiv i sion -Section 9,
Circular
Depth of Flow
24.0000 in
20.5100 cfs
0.0125 ft/ft
0.0140
\
,....ti 17.3645 in I
3.1416 ft2
2.4341 ft2
48.8221 in
75 .3982 in
8.4260 fps
7.1795 in
72.3523 %
23.4860 cfs
7.4758 fps
Victoria Avenue & Castlegate Dr i ve Ex t e nsion
Coll eg e Statio n, Texa s
Pipe 4 -10 Year St orm
Manning Pipe Calculator
Given I npu t Da t a :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowr ate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Ci rcu l ar
De pth of Flow
27 .0000 in
25 .8600 c fs
0 .0080 ft/ft
0. 0140
21. 9396 in p.<\
3.9761 ft2
3 .4603 ft2
Wetted Perimeter . . . . . . . . . . . . . . . . 60 .6455 in
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
84.8230 in
7 .3751 fps
8 .2163 in
81 . 2579 % roo, <;
25 .7221 cfs
6 .4692 fps
Pipe 4 -100 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Results:
Depth .......................... .
Area ....................... · ·. · ·
Wetted Area .................... .
Circular
Depth of Flow
27.0000 in
27.7900 cfs
0.008 ft/ft
0. 0140
24.8870 in
3.9761 ft2
3.8318 ft2
Wetted Perimeter . . . . . . . . . . . . . . . . 69 .5124 in
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow veloc i t y ............. .
Cas t lega t e Subd ivis ion -Sectio n 9 ,
84 .8230 in
7 .2524 fps
7 .9379 in
92 .1742 %
2 5 .882 3 cfs
6.5095 fps
Vict oria Ave nue & Castlegate Drive Extension
College Station, Texas
rotlo
Pipe 5 -10 Year Storm
Manning Pipe Calculator
Given I nput Data:
Shape .......................... .
Solving for .................... .
Height ......................... .
Width .......................... .
Flowrate ....................... .
Slope .......................... .
Manning ' s n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Rectangular
Depth of Flow
24.0000 in
48.0000 in
39.8700 cfs
0.0035 ft/ft
0.0130
19.1503 in
8.0000 ft2
6.3834 ft2
86.3007 in
144.0000 in
6.2458 fps
10 .6513 in
79 .7931 %
41.2862 cfs
5 .1608 fps
Pipe 5 -100 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Height ......................... .
Width .......................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results :
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hy draulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdivision -Section 9,
Rectangular
Depth of Flow
24 .0000 in
48.0000 in
53 .7300 cfs
0.0035 ft/ft
0. 0130
23.8767 in
8.0000 ft2
7.9589 ft2
95 .7535 in
144.0000 in
6.7509 fps
11 .9691 in
99.4 864 %
41. 2862 cfs
5.1608 fps
Victoria Avenue & Castlegate Drive Extension
College Station, Texas
Pipe 6 -10 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
36.0000 in
42.8100 cfs
0.004 ft/ft
0. 0140
3 2 . 4 5 8 7 in ?;(., II
7.0686 ft2
6.7095 ft2
90.1275 in
113 . 0973 in
6.3805 fps
10. 7200 in
90.1629 %
40 .1380 cfs
5.6784 fps 3'1. ( T-
Pipe 6 -100 Year Storm
Culvert Calculator
Entered Data :
Shape .......................... .
Number of Barrels .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Circular
1
Headwater
1
1
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
CONCRETE PIPE CULVERT; NO BEVELED RING ENTRANCE
SQUARE EDGE ENTRANCE WITH HEADWALL
Off
Flowrate ....................... .
Manning' s n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Diameter ....................... .
Length ......................... .
Entrance Loss .................. .
Tailwater ...................... .
Computed Results:
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Castlegate Subdivision -Se ction 9,
57.7000 cfs
0. 0140
310.4600 ft
305.1600 ft
303.8600 ft
36.0000 in
325 .0000 ft
0.0000
0.0100 ft
311.0107 ft
0.0040 ft/ft
9 .3029 fps
Victoria Avenue & Castlegate Drive Extension
College Statio n, Texas
I
5 ...... 0 . 0
Pipe 7 -10 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................ --. ·
Wetted Area .................... .
Ci rcular
Depth of Flow
27.0000 in
17.3700 cfs
0.0060 ft/ft
0. 0140
/I
18 .0210 in )£:!
3.9761 ft2
2.8196 ft2
Wetted Perimeter . . . . . . . . . . . . . . . . 51 .6316 in
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
84 .8230 in
6.2030 fps
7.8638 in
66 .7444 %
22.2760 cfs
5.6025 fps
Pipe 7 -100 Year Storm
Manning Pipe Cal culator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Circular
Depth of Flow
27 .0000 in
23 .4100 cfs
0 .0060 ft/ft
0. 0140
23 .9231 in
3 .9761 ft2
3. 7255 ft2
Wetted Perimeter . . . . . . . . . . . . . . . . 66 .2285 in
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow v elocity ............. .
Castlegate Subdivision -Sect ion 9,
84.8230 in
6.3267 fps
8.1003 in
88 .6041 %
22.2760 cfs
5 .6025 fps
Victo ria Avenue & Castlegate Dr ive Ex tension
Co lle ge Statio n, Texa s
Pipe 8 -10 Year Sto rm
Manning Pipe Calculator
Giv en I nput Data:
Sh ape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Results :
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Circular
Depth of Flow
27 .0000 in
18.2700 cfs
0.0070 ft/ft
0. 0140
IQ., /I 17 .6787 in 1v
3.9761 ft2
2.7589 ft 2
Wetted Perimeter . . . . . . . . . . . . . . . . 50.9086 in
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radi us ............... .
Percent Ful 1 ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
84 .823 0 in
6 .6658 fps
7.8037 in
6 5 . 4 7 6 8 % 1 i; ·"' 'lo
24.0608 cfs
6.0514 fps
Pipe 8 -100 Year Storm
Manning Pipe Calculator
Given I nput Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Circular
Depth of Flow
27.0000 in
24 .6300 cfs
0.0070 ft/ft
0 . 0140
22.9460 in
3.9761 ft2
3.6016 ft2
i 1 //
Wetted Perimeter ................ 63 .3361 in
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdi vision -Sec tion 9 ,
84 .8230 in
6 .8831 fps
8 .1884 in \~d'v~ <>l19
84 .9853 % v
24.0608 cfs
6.0514 fps
Victoria Avenue & Cas t legate Driv e Ex tens ion
Co llege Station, Texas
REMOVED: Pipe 9 -10 Year Storm
REMOVED : Pipe 9 -100 Year Storm
Castlegate Subdivision -Sectio n 9,
Victoria Avenue & Castlegate Drive Extension
Co llege Station, Texas
Pipe 11 -1 0 Year Storm
Manning Pipe Calculato r
Given Input Data :
Shape .......................... .
So l ving f or .................... .
Diame t er ....................... .
Flowrat e ....................... .
Slope .......................... .
Ma nni ng 's n .................... .
Computed Resu lts :
Depth .......................... .
Area ....................... · · · · ·
We tted Area .................... .
We tte d Perime t er ............... .
Perimeter ...................... .
Velocity ....................... .
Hydrauli c Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
36.0000 in
35 .6600 cfs
0.01 50 f t /ft
0 . 0140
. 11 11 17 .3969 i n
7.0686 f t2
3.3836 f t2
55 .3423 i n
113 .0973 in
10.5747 f ps
8.8040 in
4 8 .324 8 %
75 .8536 cfs
10 .7311 fp s
Pipe 11 -100 Year Storm
Manning Pipe Calculator
Given I nput Dat a :
Shape .......................... .
Sol v ing for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Circul a r
Depth of Flow
36 .0000 in
48 .0700 cfs
0.0150 ft /ft
0 .0140
20.8459 i n
7 .0686 ft 2
4.2428 ft 2
-z, I ,,
Wetted Perimeter ................ 62.2645 in
Pe rimeter ...................... .
Ve locity ....................... .
Hydrauli c Radius ............... .
Percent Full ................... .
Ful l flow Flowrat e ............. .
Ful l flow velocit y ............. .
Cast l egate Subdivis ion -Sect ion 9 ,
113 .0973 in
11.3675 fps
9. 8124 i n le ~.~\o
57 .9053 %
75 .8536 cfs
10 .7311 fps
Vi ctori a Avenue & Castlegate Dri ve Ex t e ns ion
College Sta tion, Texas
Pipe 12 -10 Year Storm
Manning Pipe Calculator
Given I nput Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Re s u lts :
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
36 .0000 in
48.9100 cfs
0.0070 ft/ft
0. 0140
27.9053 in
7.0686 ft2
5 .8792 ft2
77 .5265 in
113.0973 in
8.3395 fps
10.9203 in
77.5147 %
51.8179 cfs
7.3307 fps
Pi pe 12 -100 Year Storm
Culvert Calculator
Entered Data :
Shape .......................... .
Number of Barrel s .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning' s n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Diameter ....................... .
Length ......................... .
Entrance Loss .................. .
Tailwater ...................... .
Computed Results:
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Castlegate Subdivision -Section 9 ,
Circular
1
Headwater
1
1
CONCRETE PIPE CULVERT; NO BEVELED RING ENTRANCE
SQUARE EDGE ENTRANCE WITH HEADWALL
Off
65.9300 cfs
0. 0140
309.9500 ft
303 .6530 ft
303 .3600 ft
36 .0000 in
42.1000 ft
0 .0000
0 .0100 ft
309 .1318 ft Inlet Control
0 .0070 ft/ft
9.3498 fps
Victoria Avenue & Castlegate Drive Extension
College Station, Texas
Pipe 13 -10 Year Storm
Manning Pipe Calculator
Given Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
42.0000 in
93.6100 cfs
0.0090 ft/ft
0. 0140
J I? // 37 .1773 in -rv
9 .6211 ft2
9.0080 ft2
102 .9077 in
131.9469 in
10 .4052 fps
12 .6049 in
88 .5174 %
88.6292 cfs
9 . 2119 fps
Pipe 13 -100 Year Storm
Culvert Calculator
Entered Data :
Shape .......................... .
Number of Barrels .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Circular
1
Headwater
1
1
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
CONCRETE PIPE CULVERT; NO BEVELED RING ENTRANCE
SQUARE EDGE ENTRANCE WITH HEADWALL
Off
Flowrate ....................... .
Manning' s n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Diameter ....................... .
Length ......................... .
Entrance Loss .................. .
Tailwater ...................... .
Computed Results:
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Castlegate Subdivision -Section 9 ,
126.1900 cfs
0. 0140
309.9500 ft
302.8600 ft
300.4900 ft
42.0000 in
263.4000 ft
0.0000
0.0100 ft
312.0533 ft
0.0090 ft/ft
13 .1326 fps
Victoria Avenue & Castlegate Drive Ex t ension
College Station , Texas
I q.0~
Pipe 14 -10 Year Storm
Manning Pipe Ca l c ulator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth o f Flow
30.0000 in
8.9100 cfs
0.0085 ft/ft
0. 0140
10.3038 in \0
4.9087 ft2
1.4922 ft2
37.5709 in
94 .24 78 in
5.9709 fps
5 .7193 in
34 .3461 %
35.1148 cfs
7.1535 fps
Pipe 14 -100 Year Storm
Manning Pipe Calculator
Given Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Circular
Depth of Flow
30 .0000 in
11.0000 cfs
0 .0085 ft/ft
0 . 0140
lt
Computed Results:
Depth .......................... . 11.5327 in
4.9087 ft2
1.7385 ft2
40 .1259 in
94.2478 in
6 .3273 fps
6 .2389 in
38 .4422 %
35 .1148 cfs
7 .1535 fps
11-//
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdivision -Section 9,
Victoria Avenue & Castlegate Drive Ex t e nsion
College Station, Texas
Pipe 15 -10 Year Storm
Manning Pipe Calculator
Given Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Circular
Depth of Flow
30.0000 in
8 .9100 cfs
0 .0085 ft/ft
0.0140
Computed Results:
Depth .......................... . " 10.3038 in I\)
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydrauli c Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
4.9087 ft2
1.4922 ft2
37.5709 in
94.2478 in
5.9709 fps
5 .7193 in
34.3461 %
35.1148 cfs
7.1535 fps
Pipe 15 -100 Year Storm
Manni ng Pipe Calculator
Given I nput Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flo w Flowrate ............. .
Full flow v elocity ............. .
Castlegate Subdivision -Section 9,
Circular
Depth of Flow
30 .0000 in
11 .0000 cfs
0.0085 ft/ft
0.0140
11 .5327 in \v
4 .9087 ft2
1 .7385 ft2
40.1259 in
94 .2478 in
6.3273 fps
6.2389 in
38 .4422 %
35.1148 cfs
7.1535 fps
Victoria Avenue & Castlegate Drive Exten sion
College Station, Texas
,,
Pipe 16 -10 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Sol v ing for .................... .
Diameter ....................... .
Flowrate ....................... .
Sl ope .......................... .
Manning' s n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circu lar
Depth of Flow
30.0000 in
8.9100 cfs
0.0085 ft /ft
0.0140
" 10.3038 i n \'D
4.9087 ft2
1. 4922 ft2
37.5709 in
94 .2478 in
5 .9709 fps
5 .7193 in
34.3461 %
35 .1148 cfs
7.1535 fps
Pipe 16 -100 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdivision -Section 9,
Circular
Depth of Flow
30 .0000 in
11.0000 cfs
0 .0085 ft/ft
0. 0140
11.5327 in
4.9087 ft2
1.7385 ft2
40 .1259 in
94 .2478 in
6 .3273 fps
6.2389 in
38.4422 %
35.1148 cfs
7.1535 fps
\ 1..,(1
Victoria Avenue & Castlegate Drive Extension
Colle ge Stat i on , Te xa s
Pipe 17 -10 Year Storm
Manning Pipe Calculat or
Given Input Data:
Shape .......................... .
Sol ving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results :
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
24.0000 in
14.3900 cfs
0.0150 ft/ft
0.0140
\2 '' 12. 8324 in ·.;
3.1416 ft2
1.7094 ft2
39 .3 652 in
75 .3982 in
8 .4181 fps
6.2531 in
53.4682 %
25.7276 cfs
8 .1894 fps
Pipe 17 -100 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results :
Depth .......................... .
Area ....................... · · · ·.
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow ve locity ............. .
Castlegate Subdivision -Section 9,
Circular
Depth of Flow
24.0000 in
17 .7700 cfs
0.0150 ft /ft
0 .0140
14 .6646 in
3.1416 ft2
2.0112 ft2
43.0732 in
75.3982 in
8.8354 fps
6.7238 in
61.1027 %
25.7276 cfs
8 .1894 fps
Victoria Avenue & Castlegate Driv e Extension
College Station, Texas
APPENDIXC
Temporary Drainage Channel Caleulations -REMOVED
35
APPENDIXD
Culvert Design Calculations
36
Drainage Area -1
Area -Ac. 0.88
sq. mi . 0.0014
Land Use Area, Ac.
Residential -1 /8 acre 0.00
Residential -1 /4 acre 0.00
Residential -1 /3 acre 0.00
Residential -1 /2 acre 0.00
Open Space/Grass 0.47
Pasture 0.00
Woods 0.00
Roads 0.41
Water 0.00
Total 0.88
Drainage Area -3
Area -Ac. 16.62
sq. mi. 0.0260
Land Use Area, Ac.
Residential -1 /8 acre 0.00
Residential -1 /4 acre 16.62
Residential -1 /3 acre 0.00
Residential -1 /2 acre 0.00
Open Space/Grass 0.00
Pasture 0.00
Woods 0.00
Roads 0.00
Water 0.00
Total 16.62
Castlegate Subdivision, Section 9
Victoria Avenue
Castlegate Drive Extension
College Station , Te xas
SCS CURVE NUMBER CALCULATIONS
Drainage Area -2
Area -Ac. 3.4
sq. mi. 0.0053
Weighted Weighted
CN CN Land Use Area, Ac. CN CN
92 0.0 Residential -1 /8 acre 0.00 92 0.0
87 0.0 Residential -1 /4 acre 2.52 87 64.5
86 0.0 Residential -1 /3 acre 0.00 86 0.0
85 0.0 Residential -1 /2 acre 0.00 85 0.0
80 42.7 Open Space/Grass 0.47 80 11 .1
80 0.0 Pasture 0.00 80 0.0
79 0.0 Woods 0.00 79 0.0
98 45.7 Roads 0.41 98 11 .8
100 0.0 Water 0.00 100 0.0
88.4 Total 3.40 87.4
Drainage Area -4
Area -Ac. 29.85
sq. mi. 0.0466
Weighted Weighted
CN CN Land Use Area. Ac. CN CN
92 0.0 Residential -1 /8 acre 0.00 92 0.0
87 87.0 Residential -1 /4 acre 18.98 87 55.3
86 0.0 Residential -1 /3 acre 0.00 86 0.0
85 0.0 Residential -1 /2 acre 9.67 85 27.5
80 0.0 Open Space/Grass 0.00 80 0.0
80 0.0 Pasture 0.80 80 2.1
79 0.0 Woods 0.40 79 1.1
98 0.0 Roads 0.00 98 0.0
100 0.0 Water 0.00 100 0.0
87.0 Total 29.85 86.1
Drainage Area -5
Area -Ac. 3.16
sq . mi. 0.0049
Land Use Area. Ac.
Residential -1 /8 acre 0.00
Residential -1 /4 acre 0.00
Residential -1 /3 acre 0.00
Residential -1 /2 acre 2.98
Open Space/Grass 0.00
Pasture 0.00
Woods 0.00
Roads 0.18
Water 0.00
Total 3.16
Drainage Area -7
Area -Ac. 0.91
sq. mi. 0.0014
Land Use Area. Ac.
Residential -1 /8 acre 0.00
Residential -1 /4 acre 0.00
Residential -1 /3 acre 0.00
Residential -1 /2 acre 0.00
Open Space/Grass 0.47
Pasture 0.00
Woods 0.00
Roads 0.44
Water 0.00
Total 0.91
Castlegate Subdivision. Section 9
Victoria Avenue
Castlegate Drive Extension
College Station. Texas
SCS CURVE NUMBER CALCULATIONS
Drainage Area -6
Area -Ac. 3.44
sq . mi. 0.0054
Weighted Weighted
CN CN Land Use Area. Ac. CN CN
92 0.0 Residential -1 /8 acre 0.00 92 0.0
87 0.0 Residential -1 /4 acre 0.00 87 0.0
86 0.0 Residential -1/3 acre 0.00 86 0.0
85 80.2 Residential -1 /2 acre 3.22 85 79.6
80 0.0 Open Space/Grass 0.00 80 0.0
80 0.0 Pasture 0.00 80 0.0
79 0.0 Woods 0.00 79 0.0
98 5.6 Roads 0.22 98 6.3
100 0.0 Water 0.00 100 0.0
85.7 Total 3.44 85.8
Drainage Area -8
Area -Ac. 16.27
sq. mi . 0.0254
Weighted Weighted
CN CN Land Use Area. Ac. CN CN
92 0.0 Residential -1/8 acre 0.00 92 0.0
87 0.0 Residential -1 /4 acre 0.00 87 0.0
86 0.0 Residential -1 /3 acre 0.00 86 0.0
85 0.0 Residential -1 /2 acre 9.55 85 49.9
80 41.3 Open Space/Grass 3.25 80 16.0
80 0.0 Pasture 0.00 80 0.0
79 0.0 Woods 0.60 79 2.9
98 47.4 Roads 0.37 98 2.2
100 0.0 Water 2.50 100 15.4
88.7 Total 16.27 86.4
Drainage Area -9
Area -Ac. 135.58
sq. mi. 0.2118
Land Use Area. Ac.
Residential -1 /8 acre 0.00
Residential -1 /4 acre 0.00
Residential -1 /3 acre 0.00
Residential -1 /2 acre 0.00
Open Space/Grass 0.00
Pasture 67.60
Woods 67.60
Roads 0.00
Water 0.38
Total 135.58
Drainage Area -11
Area -Ac. 36.65
sq. mi. 0.0573
Land Use Area. Ac.
Residential -1 /8 acre 36.65
Residential -1 /4 acre 0.00
Residential -1 /3 acre 0.00
Residential -1 /2 acre 0.00
Open Space/Grass 0.00
Pasture 0.00
Woods 0.00
Roads 0.00
Water 0.00
Total 36.65
Castlegate Subdivision, Section 9
Victoria Avenue
Castlegate Drive Extension
College Station. Texas
SCS CURVE NUMBER CALCULATIONS
Drainage Area -10
Area -Ac. 22.63
sq. mi. 0.0354
Weighted Weighted
CN CN Land Use Area. Ac. CN CN
92 0.0 Residential -1 /8 acre 19.08 92 77.6
87 0.0 Residential -1 /4 acre 0.00 87 0.0
86 0.0 Residential -1 /3 acre 0.00 86 0.0
85 0.0 Residential -1 /2 acre 0.00 85 0.0
80 0.0 Open Space/Grass 2.40 80 8.5
80 39.9 Pasture 0.00 80 0.0
79 39.4 Woods 0.00 79 0.0
98 0.0 Roads 1.15 98 5.0
100 0.3 Water 0.00 100 0.0
79.6 Total 22.63 91 .0
Drainage Area -12
Area -Ac. 2.78
sq . mi . 0.0043
Weighted Weighted
CN CN Land Use Area. Ac. CN CN
92 92.0 Residential -1 /8 acre 2.78 92 92.0
87 0.0 Residential -1 /4 acre 0.00 87 0.0
86 0.0 Residential -1 /3 acre 0.00 86 0.0
85 0.0 Residential -1 /2 acre 0.00 85 0.0
80 0.0 Open Space/Grass 0.00 80 0.0
80 0.0 Pasture 0.00 80 0.0
79 0.0 Woods 0.00 79 0.0
98 0.0 Roads 0.00 98 0.0
100 0.0 Water 0.00 100 0.0
92.0 Total 2.78 92.0
Drainage Area -13
Area -Ac. 2.09
sq . mi. 0.0033
Land Use Area. Ac.
Residential -1 /8 acre 2.09
Residential -1 /4 acre 0.00
Residential -1 /3 acre 0.00
Residential -1 /2 acre 0.00
Open Space/Grass 0.00
Pasture 0.00
Woods 0.00
Roads 0.00
Water 0.00
Total 2.09
Drainage Area -15
Area -Ac. 52 .55
sq. mi. 0.0821
Land Use Area. Ac.
Residential -1 /8 acre 25.00
Residential -1 /4 acre 0.00
Residential -1 /3 acre 20.25
Residential -1 /2 acre 0.00
Open Space/Grass 8.90
Pasture 0.00
Woods 0.00
Roads 1.40
Water 0.00
Total 55.55
Castlegate Subdivision, Section 9
Victoria Avenue
Castlegate Drive Extension
College Station , Texas
SCS CURVE NUMBER CALCULATIONS
Drainage Area -14
Area -Ac. 8.34
sq. mi. 0.0130
Weighted Weighted
CN CN Land Use Area. Ac. CN CN
92 92.0 Residential -1 /8 acre 0.00 92 0.0
87 0.0 Residential -1 /4 acre 0.00 87 0.0
86 0.0 Residential -1 /3 acre 8.34 86 86.0
85 0.0 Residential -1 /2 acre 0.00 85 0.0
80 0.0 Open Space/Grass 0.00 80 0.0
80 0.0 Pasture 0.00 80 0.0
79 0.0 Woods 0.00 79 0.0
98 0.0 Roads 0.00 98 0.0
100 0.0 Water 0.00 100 0.0
92.0 Total 8.34 86.0
Weighted
CN CN
92 41.4
87 0.0
86 31.4
85 0.0
80 12.8
80 0.0
79 0.0
98 2.5
100 0.0
88.0
Revised Culvert No. 1 -25 Year Storm
Culvert Calculator
Entered Data:
Shape .................... .
Number of Barrels ...... .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning's n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Height ......................... .
Width . . . . . . . . . . . . . . . . . . . . .... .
Length ................. .
Entrance Loss .......... .
Tailwater .............. .
Computed Results:
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Rectangular
1
Headwater
8
1
BOX CULVERT WITH FLARED WINGWALLS; NO INLET TOP EDGE BEVEL
WINGWALLS FLARED 30 TO 75 DEGREES
Off
199 .0000 cfs
0 .0130
314.0000 ft
305.6700 ft
305.0000 ft
48.0000 in
96.0000 in
67.0000 ft
0.4000
4.0000 ft
309.9922 ft Inlet Control
0.0100 ft/ft
13 .3998 fps
Revised Culvert No. 1 -100 Year Storm
Culvert Calculator
Entered Data :
Shape .......................... .
Number of Barrels .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning' s n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Height ......................... .
Width .......................... .
Length ................... .
Entrance Loss ...
Tailwater ...
Computed Results:
Headwater ............ .
Slope ................ .
Velocity ............. .
Castlegate Subdivision -Section 9,
Rectangular
1
Headwater
8
1
BOX CULVERT WITH FLARED WINGWALLS; NO INLET TOP EDGE BEVEL
WINGWALLS FLARED 30 TO 75 DEGREES
Off
239.0000 cfs
0. 0130
314. 0000 ft
305.6700 ft
305.0000 ft
48 .0000 in
96 .0000 in
67.0000 ft
0 .4000
4.0000 ft
310 .9294 ft Inlet Control
0.0100 ft/ft
14.1787 fps
Victoria Avenue & Castlegate Drive Extension
College Station, Texas
•••
Castlegate Subdivision
Section 9
Size Inlet ,,
Pipe# Length Slope Invert Elev
(In) (ft) (%) (ft)
1 18 31 .6 2.00 308.21 - --. --·
2 24 46.4 1.50 307.09 -·---4 27 124.3 0.80 306.40 -··--5 4x2 42.0 0.35 305.36
"'6 . -· 36 325.0 0.40 305.16
---i.-· ---·
····-·-------------3 24 63.7 1.25 307.44 ------------· --
-··---------· ------------7 27 31 .1 0.60 308.15 .. -····-----··-·--I------~-· 8 27 233.9 0.70 307.86 -------------Q 'J+. ~ Q..+Q ~ ---------
Temp CRaAAel ~ +.45 ~ ..
11 36 142.4 1.50 305.89 ----~-->--· -12 36 42.1 0.70 303.65 --··---_ .. --13 42 263.4 0.90 302.86
Outlet
Invert Elev
(ft)
307.58
306.39
305.41
305.21
303.86
306.64
307.96
. 306.22
~
~
303.75
303.36
300.49
1 O year storm 100 year storm
*Actual Flow Design Flow Y10 % Full Tr1vel Time, tn1 *Actual Flow Design Flow Y100 % Full Travel Time, t1100
(cfs) (cfs) (fps) (sec) (min) (cfs) (cfs) (fps) (sec) (min)
7.02 11 .34 8.7 68.3 4 0.06 7.52 12.14 8.8 72.0 4 0.06
14.09 22.76 9.2 71 .7 I 5 0.08 15.09 24.37 9.3 77.6 5 0.08
25.86 7.4 81.3_) 17 0.28 27.79 7.3 92 .2 17 0.28
39.87 6.2 ~79.8 7 0.11 53.73 6.8 99.5 6 0.10
42.81 6:4 ( 90.21 51 0.85 57.70 9.3 100.0 35 0.58 --
·----·-· -. -----
11 .77 19.01 8.3 68.2 8 0.13 12.70 20.51 8.4 72.4 8 0.13 ---·--·-··-------·---------------·--
·--·---------·-· ·-· ·-----------------------17.37 6.2 66.7 5 0.08 23.41 6.3 88.6 5 0.08 -· 18.27 6.7 65.5 35 0.58 24.63 6.9 85.0 34 0.56 ·----------~·----~ ~ 6,..7 ~ J ~ ~ 9,.9 ~ J ~ ------------------..__ ___ ---------
----------·-·-----------------·--·-----35.66 10.6 48.3 13 0.22 48.07 11.4 57.9 12 0.21 ·------------48.91 8.3 77.5 5 0.08 65.93 9.3 100.0 5 0.08 . -----·-··---·------·-->---------~-
93.61 10.4 88.5 25 0.42 126.19 13.1 100.0 20 0.34 .. ------·-----·-·------------
-----17 24 24.2 1.50 306.13 305.77 8.91 14.39 8.4 53.5 3 0.05 11 .00 17.77 8.8 61 .1 ---·----..
16 30 154.0 0.85 305.52 304.21 8.91 6.0 34.3 26 0.43 11 .00 6.3 38.4 ···-··--------15 30 237.9 0.85 304.12 302.10 8.91 6.0 34.3 40 0.66 11 .00 6.3 38.4 -. ---. -
14 30 59.0 0.85 302.00 301 .50 8.91 6.0 34.3 10 0.16 11 .00 6.3 38.4
*These values reflect the actual flow for the 18" & 24" pipes. The design flow for these pipe sizes reflects a 25% reduction in pipe area.
(Refer to attached calculation for specific information.)
3 0.05
24 0.41
38 0.63
9 0.16
Removed
Removed
Revi sed Culvert No. 2 -25 Year Storm
Culvert Calculator
Entered Data :
Shape ........................ .
Number of Barre ls ............ .
Solving for ................... .
Chart Number .................. .
Scale Number ............... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning's n .................... .
Roadway Elevation ............ .
Inlet Elevation .............. .
Outlet Elevation ............. .
Height ....................... .
Width ........................ .
Length ....................... .
Entrance Loss .
Tailwater .....
Computed Results:
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Rectangular
2
Headwater
8
1
BOX CULVERT WITH FLARED WINGWALLS ; NO INLET TOP EDGE BEVEL
WINGWALLS FLARED 30 TO 75 DEGREES
Off
507.0000 cf s
0. 0130
307 .8000 ft
300.4500 ft
300.0600 ft
48.0000 in
96. 0000 in
65.0000 ft
0.4000
4.0000 ft
306.0938 ft Inlet Control
0 .0060 ft/ft
12.0520 fps
Revised Culvert No. 2 -100 Year Storm
Culvert Calculator
Entered Data:
Shape .......................... .
Number of Barrels .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning' s n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Height ......................... .
Width .......................... .
Length ......................... .
Entrance Loss .................. .
Tailwater ...
Computed Results :
Headwater . . . . . ................ .
Slope . . . . . . . . ............. .
Velocity ....................... .
Castlegate Subdivision -Section 9 ,
Rectangular
2
Headwater
8
1
BOX CULVERT WITH FLARED WINGWALLS; NO INLET TOP EDGE BEVEL
WINGWALLS FLARED 30 TO 75 DEGREES
On
670.0000 cfs
0. 0130
307 .8000 ft
300 .4500 ft
300.0600 ft
48 .0000 in
96.0000 in
65 .0000 ft
0.4000
4 .0000 ft
307 .8974 ft Inlet Control; Overtops
0 .0060 ft/ft
13 . 0250 fps
Victoria Avenue & Cas tlegate Drive Extension
College Station, Texas
EXHIBIT A
Offsite Infrastructure Plan for Castlegate Subdivision
4.3
EXHIBIT B
Post-Development Drainage Area Map -Culvert Design
45
EXHIBIT C
Post-Development Drainage Area Map -Storm Sewer Design
4 7