HomeMy WebLinkAboutDrainage ReportDrainage Report
for
Saddle Creek Subdivision, Phase 6
Brazos County, Texas
July 2013
Engineer:
Schultz Engineering, LLC
TBPE Firm No. 12327
P.O. Box 11995
College Station, TX 77842
2730 Longmire Drive, Suite A
College Station, Texas 77845
(979)764-3900
Developer:
Saddle Creek Partners, Ltd.
4440 Bentwood Drive
College Station, Texas 77845
Phone: (979) 690-2642
Saddle Creek Subdivision, Phase 6
Drainage Report
ENGINEER
Schultz Engineering, LLC.
P.O. Box 11995
College Station, Texas 77842
Phone: (979) 764-3900
Fax:(979) 764
OWNERIDEVELOPER
Saddle Creek Partners, Ltd.
4440 Bentwood Drive
College Station, Texas 77845
Phone: (979)690-2642
GENERAL DESCRIPTION AND LOCATION
Location: Saddle Creek Subdivision, Phase 6, is located on the south west side of FM 2154, off of
Stousland Rd.
Description:
• Area:
• Proposed Land Use.
• # of Lots:
• Existing Land Use:
• Land Description:
Primary Drainage Facility:
Flood Hazard Information:
FEMA FIRM:
Floodplain:
25.546 acres
Single Family Residential
16 lots
Vacant
The terrain slopes towards the southwest.
Boggy Creek
# 48041C0375E (May 16, 2012)
Un-shaded Zone X
HYDROLOGIC CHARACTERISTICS
The existing site is predominately wooded. The elevations range from 304 to 272, sloping generally in a south
westerly direction. The runnoff enters tributaries of Boggy Creek.
GENERAL STORMWATER PLAN
The drainage plan for this development will involve the construction of ditches, channels and the installation of a
culvert structure.
DRAINAGE DESIGN
General (formation: Stormwater runoff from Phase 6 of the subdivision will be collected in the ditches along
Vinatge Oaks Court to be discharged into a proposed drainage channel. The proposed
channel will discharge into an existing drainage way. See Exhibits A and B for drainage
areas and culvert and channel locations.
Page 1 of 3
T, Methodology:
TR 55
T, Minimum
10 minutes
Design Storm Event:
25-year & 100-year -residential street & culvert, drainage channel
Culvert Materials:
HDPE Pipe with cement stabilized sand backfill
Manning's n Value:
0.012
Runoff Coefficient:
0.45
The Rational Equation was used for the ditch and channel design
Design Results — Culvert Pipe:
Design Results — Channel:
Applicable Exhibits:
Culvert No.
601
Culvert Size
3-24" Pipes
Top of Road Elev
283.09
Qz5
50.32
V25
6.75
HW25
281.50
Qioo
60.15
Viao
7.41
HW,00
281.36
The data presented above and in the Appendices indicates the culvert size is in accordance
with the requirements. The head water elevation for the culvert is less than the top of road
elevation for the 100-yr storm runoff. The ditch at the outlet of the proposed culvert will
be lined with rock riprap to prevent erosion from high velocities. The velocities in the
roadside ditches will be such that grass lined ditches are adequate.
Channel No.
1
Sloe
0.8
z5
54.89
Vz5
3.40
D25
1.44
as
65.55
Vioo
3.56
Dioo
1.56
Channel No. 1 has a 4' bottom width, 5H:1 V side slopes. The channel will have a
minimum depth of 2' for adequate freeboard. The design velocity is less than 4.5 fps
which allows a grass lined channel.
Exhibit A —
Drainage Area Map — Culvert 601
Exhibit B -
Drainage Area Map
Appendix A —
Drainage Area Summary
Appendix B —
Time of Concentration
Appendix C —
Pipe Design Summary & Culvert Reports
Appendix D -
Ditch Design Summary
Appendix E -
Channel Design Summary and Reports
Page 2 of 3
F-12391 `
SCHUL Z ENGINEERING LLd
CONCLUSION The culverts, roadside ditches, and drainage channel for this subdivision were designed in
accordance with appropriate engineering standards.
CERTIFICATION
I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report for the drainage design
for Saddle Creek Subdivision, Phase 6, was prepared by me in accordance with the requirements of the Brazos County Road
and Bridge Department.
,6�/3
Jos P. chintz, P.E.
Page 3 of 3
Exhibit A
Drainage Area Map — Culvert 601
126
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23
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128
601,
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oc
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301
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Schultz Engineering, LLC
2?M t�. 5�9 A
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iu�7ii'll PCP JP3 13-235 2013
SADDLE CREEK SUBDIVISION DRAINAGE AREA SCALE EXHIBIT
PHASE 6
BMZOS COUNTY, TX MAP
Exhibit B
Drainage Area Map — Ditch Design
126
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24
128
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JPS SCi JPS 13-255 JUNE 2015
SCALE EXHIBIT
SADDLE CREEK SUBDIVISION DRAINAGE AREA
BnaPHASEZOS 6 MAP
TX
DITCH DESIGN � 13-253
Appendix A
Drainage Area Summary
Saddle Creek Subdivision - Phase 6
Appendix A Drainage Area Summary
Area #
Area, A
(acres)
C
te
(min)
25 year storm
100 year storm
125
(in/hr)
Q25
(cfs)
1100
(in/hr)
Q100
(cfs)
301
25.61
0.45
46.0
4.367
50.32
5.219
60.15
301A
5.03
0.45
10.0
9.861
22.32
11.639
26.35
301B
0.31
_ _
0.45
_
10.0
9.861
1.38
11.639
1.62
301C
0.50
0.45
10.0
9.861
2.22
_
11.639
2.62
301 D
19.76
0.45
46.0
4.367
38.83
5.219
46.41
302
1.03 __.._
0.45
10.0
9.861
4.57
11.639
5.39
302A _
0.20
_
0.45 _
10.0
_
9.861_
0.89___
11.639_
1.05__
3028
O.t7 _
0.45 _
10.0
9.881
0.75
11.639
0.89
302C
0.66
0.45
10.0
9.861
2.93
11.639
3.46
The Rational Method:
Q = CIA
Q = Flow (cfs)
A = Area (acres)
C = Runoff Coeff.
I = Rainfall Intensity (in/hr)
Brazos County:
I = b / (tc+d)e
tc = Time of concentration (min)
25 year storm 100 year storm
b = 89 b = 96
d = 8.5 d = 8.0
a = 0.754 e = 0.730
t, = L/(V*60)
L = Length (ft
V = Velocity (ft/sec)
Appendix B
Time of Concentration
m
m
U)
LL
Appendix C
Culvert Design Summary
& Culvert Reports
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Culvert Report
Hydraflow Express Extension for AutOCAD® Civil 3DB 2013 by Aulodesk, Inc. Tuesday, Jul 9 2013
Pipe 601 - 25 yr Storm
Invert Elev Din (ft)
= 278.66
Calculations
Pipe Length (ft)
= 67.00
Qmin (cfs)
= 50.32
Slope (%)
= 0.81
Qmax (cfs)
= 60.15
Invert Elev Up (ft)
= 279.20
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 24.0
Shape
= Circular
Highlighted
Span (in)
= 24.0
Qtotal (cfs)
= 50.32
No. Barrels
= 3
Qpipe (cfs)
= 50.32
n-Value
= 0.012
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 5.79
Culvert Entrance
= Groove end projecting (C)
Veloc Up (ft/s)
= 6.75
Coeff. K,M,c,Y,k
= 0.0045, 2, 0.0317, 0.69, 0.2
HGL Dirt (ft)
= 280.40
HGL Up (ft)
= 280.68
Embankment
Hw Elev (ft)
= 281.50
Top Elevation (ft)
= 283.09
Hw/D (ft)
= 1.15
Top Width (ft)
= 30.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 30.00
a. (e)
284M
28300
28200
261.00
28e00
2]9.00
2)8.00
21M
Pipe 601-25 yr Storrs
CkWarCulved - HOL Embank
H. OepM (8)
Culvert Report
Hydraflow Express Extension for AUtoCAD® Civil 3D® 2013 by Autodesk, Inc. Tuesday, Jul 9 2013
Pipe 601 - 100 yr Storm
Invert Elev Dn (ft)
= 278.66
Calculations
Pipe Length (ft)
= 67.00
Qmin (cfs)
= 50.32
Slope (%)
= 0.81
Qmax (cfs)
= 60.15
Invert Elev Up (ft)
= 279.20
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 24.0
Shape
= Circular
Highlighted
Span (in)
= 24.0
Qtotal (cfs)
= 60.15
No. Barrels
= 3
Qpipe (cfs)
= 60.15
n-Value
= 0.012
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 6.72
Culvert Entrance
= Groove end projecting (C)
Veloc Up (ft/s)
= 7.41
Coeff. K,M,c,Y,k
= 0.0045, 2, 0.0317, 0.69, 0.2
HGL Dn (ft)
= 280.46
HGL Up (ft)
= 280.81
Embankment
Hw Elev (ft)
= 281.86
Top Elevation (ft)
= 283.09
Hw/D (ft)
= 1.33
Top Width (ft)
= 30.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 30.00
elav (ft)
294.00
283.00
282.00
281 M
28000
279.00
278A0
277,00
Pipe 601-100 yr Storm
— ch.lercelved HOL — embank
Hwoeplh(ft)
I80
380
2,80
1.80
0.80
.0.20
-1.20
Appendix D
Ditch Design Summary
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Appendix E
Channel Design Summary
& Reports
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Channel Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2013 by Autodesk, Inc.
Channel No 1
- 25 yr Storm
Trapezoidal
Bottom Width (ft)
= 4.00
Side Slopes (z:1)
= 5.00, 5.00
Total Depth (ft)
= 2.00
Invert Elev (ft)
= 278.66
Slope (%)
= 0.80
N-Value
= 0.035
Calculations
Compute by:
Known Q
Known Q (cfs)
= 54.89
Elev (ft)
Highlighted
Depth (ft)
Q (cfs)
Area(sgft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (ft)
Tuesday, Jul 9 2013
= 1.44
= 54.89
= 16.13
= 3.40
= 18.69
= 1.16
= 18.40
= 1.62
Depth (ft;
289.00
2.34
280.50
280.00
279.50
279.00
278.50
0711. OO
Secti n 9
1.84
1.34
0.34
5 10 15 20 25 30
Reach (ft)
35
Channel Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2013 by Autodesk, Inc.
Channel No 1
- 100 yr Storm
Trapezoidal
Bottom Width (ft)
= 4.00
Side Slopes (z:1)
= 5.00, 5.00
Total Depth (ft)
= 2.00
Invert Elev (ft)
= 278.66
Slope (%)
= 0.80
N-Value
= 0.035
Calculations
Compute by:
Known Q
Known Q (cfs)
= 65.55
Elev
281.00
280.50
280.00
279.50
279.00
278.50
278.00
(ft)
Section
Tuesday, Jul 9 2013
Highlighted
Depth (ft)
= 1.56
Q (cfs)
= 65.55
Area (sgft)
= 18.41
Velocity (ft/s)
= 3.56
Wetted Perim (ft)
= 19.91
Crit Depth, Yc (ft)
= 1.27
Top Width (ft)
= 19.60
EGL (ft)
= 1.76
------------
- kf-
Depth (ft;
2.34
1.84
1.34
�!
0.34
0.16
5 10 15 20 25 30
Reach (ft)
35