HomeMy WebLinkAboutTechnical Design SummaryGreat Oaks Subdivision, Phases 13 & 14
Stormwater Management Technical Design Summary Report
MBESI No. 10280002
1 PART 1— Executive Summary Report
Section 1— Contact Information
Project Designer: McClure and Browne Engineering and Surveying, Inc.
1008 Woodcreek Drive, Suite 103
College Station, TX 77845
979-693-3838
Project Developer: Caldwell Companies.
College Station, TX 77845
(979)690-1222
Section 2 — General Information and Project Location
This development is the 13' and 14' phase of a 14 phase subdivision. The phase 13 consists of 5 lots
and phase 14 consists of 13 lots. The phases are located approximately 4,000 ft. to the northwest of the
intersection of Rock Prairie Rd. W. and Great Oaks Dr. The entire subdivision has been analyzed in the
initial drainage report submitted in July, 2000. The development is entirely located within the city
limits of College Station.
The project site is in the Hope Creek watershed. According to the Flood Insurance Rate Maps for
Brazos County, Texas and incorporated area, Map Number 48041CO305E effective May 16, 2012; no
portion of this property is located in a 100-year flood hazard area.
The inlet and pipe diameter calculations are shown with this submittal.
Section 3 — Reference
Exhibit A
Vicinity Map
Exhibit B
Excerpt from FEMA FIRM
n Exhibit C
Inlet, Pipe, & Culvert Calculations
V Exhibit D
Drainage Area Map for Inlets
Exhibit E
Technical Design Summary
U
Drainage Report 1
Great Oaks, Phases 13 & 14
Drainage Report
Great Oaks, Phases 13 & 14
EXHIBIT A
Vicinity Map
Drainage Report
Great Oaks, Phases 13 & 14
SCALE: 1" = 2000'
0 1000' 2000' 4000'
EXHIBIT "A"
VICINITY MAP
GREAT OAKS, PHASES 13 & 14
COLLEGE STATION BRAZOS COUNTY, TEXAS
mmmunumume
Drainage Report
Great Oaks, Phases 13 & 14
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EXHIBIT C
Inlet, Pipe, & Culvert Calculations
Drainage Report
Great Oaks, Phases 13 & 14
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Wednesday, Nov 7 2012
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil 3D@ 2012 by Autodesk, Inc.
= 278.55
= 361.00
= 3.45
= 291.00
= 30.0
= Circular
= 30.0
=1
= 0,013
= Circular Concrete
= Square edge w/headwall (C)
= 0.0098, 2, 0.0398, 0.67, 0.5
= 298.00
= 40.00
= 40.00
Calculations
Qmin (cfs)
Qmax (cfs)
Tailwater Elev (ft)
Highlighted
Qtotal (cfs)
Qpipe (cfs)
Qovertop (cfs)
Veloc Dn (ft/s)
Veloc Up (ft/s)
HGL Dn (ft)
HGL Up (ft)
Hw Elev (ft)
Hw/D (ft)
Flow Regime
= 25.60
= 25.60
= Normal
= 25.60
= 25.60
= 0.00
= 13.95
= 7.09
= 279.55
= 292.72
= 293.73
= 1.09
= Inlet Control
Hw Depth (ft)
.n 302.00 11.00
298.00
MerwiId
290.00
30 in. Grate Pipe - 2 yr. Storm
Invert Elev Dn (ft)
Pipe Length (ft)
Slope (%)
Invert Elev Up (ft)
Rise (in)
Shape
Span (in)
No. Barrels
n-Value
Culvert Type
Culvert Entrance
Coeff. K,M,c,Y,k
Embankment
Top Elevation (ft)
Top Width (ft)
Crest Width (ft)
Elev (ft)
Profile
w
_ -Emb - -- - -- -
282.00
278.00
274 00
0.0
LI
50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0 500.0 550.0 600.0
Reach (ft)
7.00
3.00
-1.00
-5.00
-9.00
-13.00
47 nn
Culvert Report
Hydraftow Express Extension for AutoCAD® Civil 31D®2012 by Autodesk, Inc.
30 in. Grate Pipe - 5 yr. Storm
Invert Elev Dn (ft)
Pipe Length (ft)
Slope (%)
Invert Elev Up (ft)
Rise (in)
Shape
Span (in)
No. Barrels
n-Value
Culvert Type
Culvert Entrance
Coeff. K,M,c,Y,k
l Embankment
Top Elevation (ft)
Top Width (ft)
Crest Width (ft)
GElev (ft)
= 278.55
= 361.00
= 3.45
= 291.00
= 30.0
= Circular
= 30.0
=1
= 0.013
= Circular Concrete
= Square edge w/headwall (C)
= 0.0098, 2, 0.0398, 0.67, 0.5
Calculations
Qmin (cfs)
Qmax (cfs)
Tailwater Elev (ft)
Highlighted
Qtotal (cfs)
Qpipe (cfs)
Qovertop (cfs)
Veloc Dn (ft/s)
Veloc Up (ft/s)
HGL Dn (ft)
HGL Up (ft)
Hw Elev (ft)
Hw/D (ft)
Flow Regime
Wednesday, Nov 7 2012
= 31.20
= 31.20
= Normal
= 31.20
= 31.20
= 0.00
= 14.68
= 7.79
= 279.67
= 292.90
= 294.24
= 1.30
= Inlet Control
Hw Depth (ft)
302.00 11.00
B298.00
294.00
290.00
286,00
282.00
278.00
C274.00
Profile
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MENOMINEE
0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0 500.0 550.0 600.0
7.00
3.00
1.00
W11111
•I We
-13.00
-17 nn
Reach (ft)
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc.
Wednesday, Nov 7 2012
II 30 in. Grate Pipe -10
yr. Storm
Invert Elev Dn (ft)
= 278.55
Calculations
Pipe Length (ft)
= 361.00
Qmin (cfs)
= 35.10
Slope (%)
= 3.45
Qmax (cfs)
= 35.10
i' Invert Elev Up (ft)
= 291.00
Tailwater Elev (ft)
= Normal
Rise (in)
= 30.0
Shape
= Circular
Highlighted
f Span (in)
= 30.0
Qtotal (cfs)
= 35.10
No. Barrels
= 1
Qpipe (cfs)
= 35.10
n-Value
= 0.013
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 15.08
Culvert Entrance
= Square edge w/headwall (C)
Veloc Up (ft/s)
= 8.30
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
HGL Dn (ft)
= 279.75
HGL Up (ft)
= 293.01
Embankment
Hw Elev (ft)
= 294.67
Top Elevation (ft)
= 298.00
Hw/D (ft)
= 1.47
C Top Width (ft)
= 40.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 40.00
IElev (ft)
p 302.00
298.00
C294.00
290.00
lu
286.00
IC
282.00
I_
278.00
I_Y 274.00
I .0
Profile Hw Depth (ft)
11.00
Hw
--- -- --- - mbank ent-- - -
0000
0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0 500.0 550.0 600.0
Reach (ft)
VAIR
3.00
-1.00
-5.00
MITIl]
-1 &00
-17 nn
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc. Wednesday, Nov 7 2012
30 in. Grate Pipe - 25 yr. Storm
Invert Elev Dn (ft)
= 278.55
Calculations
Pipe Length (ft)
= 361.00
Qmin (cfs)
= 40.20
Slope (%)
= 3.45
Qmax (cfs)
= 40.20
Invert Elev Up (ft)
= 291.00
Tailwater Elev (ft)
= Normal
Rise (in)
= 30.0
Shape
= Circular
Highlighted
Span (in)
= 30.0
Qtotal (cfs)
= 40.20
No. Barrels
= 1
Qpipe (cfs)
= 40.20
n-Value
= 0.013
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 15.70
Culvert Entrance
= Square edge w/headwall (C)
Veloc Up (ft/s)
= 9.01
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
HGL Dn (ft)
= 279.84
HGL Up (ft)
= 293.13
Embankment
Hw Elev (ft)
= 295.30
Top Elevation (ft)
= 298.00
Hw/D (ft)
= 1.72
Top Width (ft)
= 40.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 40.00
Elev (ft) Profile Hw Depth (ft)
302.00 11.00
IMEM1116A
294.00
290.00
286.00
1l,
282.00
Ij 278.00
274.00
- - - ------ - - --- yr _-
-rribankff e t -- ---
0
'000-
---------
0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0 500.0 550.0 600.0
VAR
3.00
-1.00
-5.00
Milif
-13.00
-17.00
Reach (ft)
Culvert Report
Hydratlow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc.
30 in. Grate Pipe - 50 and 100 yr. Storm
Invert Elev Dn (ft)
Pipe Length (ft)
Slope (%)
Invert Elev Up (ft)
Rise (in)
Shape
Span (in)
No. Barrels
n-Value
Culvert Type
Culvert Entrance
Coeff. K,M,c,Y,k
Embankment
Top Elevation (ft)
Top Width (ft)
Crest Width (ft)
= 278.55
= 361.00
= 3.45
= 291.00
= 30.0
= Circular
= 30.0
=1
= 0.013
= Circular Concrete
= Square edge w/headwall (C)
= 0.0098, 2, 0.0398, 0.67, 0.5
Calculations
Qmin (cfs)
Qmax (cfs)
Tailwater Elev (ft)
Highlighted
Qtotal (cfs)
Qpipe (cfs)
Qovertop (cfs)
Veloc Dn (ft/s)
Veloc Up (ft/s)
HGL Dn (ft)
HGL Up (ft)
Hw Elev (ft)
Hw/D (ft)
Flow Regime
Wednesday, Nov 7 2012
= 42.60
= 42.60
= Normal
= 42.60
= 42.60
= 0.00
= 9.38
= 9.38
= 280.73
= 293.18
= 295.63
= 1.85
= Inlet Control
Elev (ft) Profile Hw Depth (ft)
302.00
i
1
11.00
298.00
7.00
--
294.00
- ---
-
-
---------
_
3.00
286.00
-5.00
282.00
a
-
1
_9.00
274.00
---------------
-17.00
0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0 500.0 550.0 600.0
Reach (ft)
EXHIBIT
CULVERT OVERVIEW
Great Oaks Subdivision
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W
on
F
U
d
r
cfs
ft
-as
ft/s
2
34.6
43.0
13.310
48.9
13.725
56.2
L311.110.05
14.450
63.8
14.8100
72.2
15.3
Culvert Flowline Up
300.52
Culvert Flowline Down
299.00
Embankment Elv.
308.50
Grate Open Area (SF)
1 4.72
'Includes 33% Flow Increase for pipe sizes 127" dia. 11/07/2012
"" See Plan & Profile for pipe slope used (Pipe slope >or= Friction slope) Grate SpreadsheetAs
Culvert Report
Hydratlow Express Extension for AutoCAD® Civil 3D®2012 by Autodesk, Inc. Tuesday, Nov 6 2012
Arboleda Dr. 42 in. Culvert
Invert Elev Dn (ft)
= 299.00
Calculations
Pipe Length (ft)
= 52.00
Qmin (cfs)
= 34.60
Slope (%)
= 2.40
Qmax (cfs)
= 34.60
Invert Elev Up (ft)
= 300.25
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 42.0
Shape
= Circular
Highlighted
Span (in)
= 42.0
Qtotal (cfs)
= 34.60
No. Barrels
= 1
Qpipe (cfs)
= 34.60
n-Value
= 0.013
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 4.41
Culvert Entrance
= Square edge w/headwall (C)
Veloc Up (ft/s)
= 6.83
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
HGL Dn (ft)
= 301.66
HGL Up (ft)
= 302.07
Embankment
Hw Elev (ft)
= 302.88
Top Elevation (ft)
= 308.50
Hw/D (ft)
= 0.75
Top Width (ft)
= 24.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 42.00
Elev (a)
� I 309.00
307.00
305.03
303.00
301 00
299.01)
297.0D
Arboleda Dr, 42 in. Culvert
- CDcular Culvert - HGL - Embank
Hw Depth (to
e.76
5.75
4.75
2.75
0.76
-1.25
-3.25
Reach (a)
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil MOD 2012 by Autodesk, Inc. Tuesday, Nov 6 2012
Arboleda Dr. 42 in. Culvert
Invert Elev Dn (ft)
= 299.00
Calculations
Pipe Length (ft)
= 52.00
Qmin (cfs)
= 43.00
Slope (%)
= 2.40
Qmax (cfs)
= 43.00
Invert Elev Up (ft)
= 300,25
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 42.0
Shape
= Circular
Highlighted
Span (in)
= 42.0
Qtotal (cfs)
= 43.00
No. Barrels
= 1
Qpipe (cfs)
= 43.00
n-Value
= 0.013
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 5.26
Culvert Entrance
= Square edge w/headwall (C)
Veloc Up (ft/s)
= 7.38
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
HGL Dn (ft)
= 301.77
HGL Up (ft)
= 302.29
Embankment
Hw Elev (ft)
= 303.29
Top Elevation (ft)
= 308.50
Hw/D (ft)
= 0.87
Top Width (ft)
= 24.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 42.00
Nov (ft)
309.00
307.00
305.00
303.00
301 00
299.00
297.00
Arboleda Dr. 42 in. Culvert
- Circular Culvert - HOL - Embank
the Depth (ft)
9.76
6.76
4.76
2.76
0.76
-1,26
.3.25
React (ft)
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil 3D®2012 by Autodesk, Inc. Tuesday, Nov 6 2012
Arboleda Dr. 42 in. Culvert
Invert Elev Dn (ft)
= 299.00
Calculations
Pipe Length (ft)
= 52.00
Qmin (cfs)
= 48.90
Slope (%)
= 2.40
Qmax (cfs)
= 48.90
Invert Elev Up (ft)
= 300.25
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 42.0
Shape
= Circular
Highlighted
Span (in)
= 42.0
Qtotal (cfs)
= 48.90
No. Barrels
= 1
Qpipe (cfs)
= 48.90
n-Value
= 0.013
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 5.85
Culvert Entrance
= Square edge w/headwall (C)
Veloc Up (ft/s)
= 7.75
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
HGL Dn (ft)
= 301.84
HGL Up (ft)
= 302.43
Embankment
Hw Elev (ft)
= 303.58
Top Elevation (ft)
= 308.50
Hw/D (ft)
= 0.95
Top Width (ft)
= 24.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 42.00
Elev (R)
309.00
307.00
305.00
30300
301.00
299.00
297.00
Arboleda Dr. 42 in. Culvert
Clrcular Culvert HGL Embank
Hw Depth (R)
6.76
6.75
4.75
2,75
0.75
-1.26
.3.25
Reach (R)
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil 3002012 by Autodesk, Inc.
Tuesday, Nov 6 2012
Arboleda Dr. 42 in.
Culvert
Invert Elev Dn (ft)
= 299.00
Calculations
Pipe Length (ft)
= 52.00
Qmin (cfs)
= 56.20
Slope (%)
= 2.40
Qmax (cfs)
= 56.20
Invert Elev Up (ft)
= 300.25
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 42.0
Shape
= Circular
Highlighted
Span (in)
= 42.0
Qtotal (cfs)
= 56.20
No. Barrels
= 1
Qpipe (cfs)
= 56.20
n-Value
= 0.013
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 6.55
Culvert Entrance
= Square edge w/headwall (C)
Veloc Up (ft/s)
= 8.20
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
HGL Dn (ft)
= 301.92
HGL Up (ft)
= 302.60
Embankment
Hw Elev (ft)
= 303.93
Top Elevation (ft)
= 308.50
Hw/D (ft)
Flow Regime
= 1.05
= Inlet Control
Top Width (ft)
= 24.00
Crest Width (ft)
= 42.00
Elev (a)
309.00
307.00
305.00
303.00
301.00
20.00
297.00
Arboleda Dr. 42 in. Culvert
�- circular culvert HGL Embank
Hw Depth
8.75
6.75
4.75
2.75
0.75
-1.25
.3.25
Reach (4)
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil 3D®2012 by Autodesk, Inc. Tuesday, Nov 6 2012
Arboleda Dr. 42 in. Culvert
Invert Elev Dn (ft)
= 299.00
Calculations
Pipe Length (ft)
= 52.00
Qmin (cfs)
= 63.80
Slope (%)
= 2.40
Qmax (cfs)
= 63.80
Invert Elev Up (ft)
= 300.25
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 42.0
Shape
= Circular
Highlighted
Span (in)
= 42.0
Qtotal (cfs)
= 63.80
No. Barrels
= 1
Qpipe (cfs)
= 63.80
n-Value
= 0.013
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 7.27
Culvert Entrance
= Square edge w/headwall (C)
Veloc Up (ft/s)
= 8.67
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
HGL Dn (ft)
= 302.00
HGL Up (ft)
= 302.75
Embankment
Hw Elev (ft)
= 304.31
Top Elevation (ft)
= 308.50
Hw/D (ft)
= 1.16
Top Width (ft)
= 24.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 42.00
Elev (to
309.00
307.00
305.00
303.00
301.00
299.00
297.00
Arboleda Dr. 42 in. Culvert
Circular Culvert - HGL - Embank
Hw Depth dr)
6.75
6.75
4.75
2.75
0.75
.1.25
3.26
Reach (6)
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc. Tuesday, Nov 6 2012
Arboleda Dr. 42 in. Culvert
Invert Elev Dn (ft)
= 299.00
Calculations
Pipe Length (ft)
= 52.00
Qmin (cfs)
= 72.20
Slope (%)
= 2.40
Qmax (cfs)
= 72.20
Invert Elev Up (ft)
= 300.25
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 42.0
Shape
= Circular
Highlighted
Span (in)
= 42.0
Qtotal (cfs)
= 72.20
No. Barrels
= 1
Qpipe (cfs)
= 72.20
n-Value
= 0.013
Qovertop (cfs)
= 0.00
Culvert Type
= Circular Concrete
Veloc Dn (ft/s)
= 8.05
Culvert Entrance
= Square edge w/headwall (C)
Veloc Up (ft/s)
= 9.20
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
HGL Dn (ft)
= 302.08
HGL Up (ft)
= 302.91
Embankment
Hw Elev (ft)
= 304.79
Top Elevation (ft)
= 308.50
Hw/D (ft)
= 1.30
Top Width (ft)
= 24.00
Flow Regime
= Inlet Control
Crest Width (ft)
= 42.00
Elev (a)
309.00
307.00
305.00
303 OD
301.00
299.0D
297.01)
Arboleda Dr. 42 In. Culvert
- Circular Culvert - HOL - Embank
Hw Depth (8)
8.75
6.75
4.75
2.76
0.75
-1.26
-325
Reach (5)
Drainage Area Map for Inlets
Drainage Report
Great Oaks, Phases 13 & 14
` Overland Flow ` _L ) \) �^
North Ditch
(1 \ L 11 Area: 3.75 Ac.
Overland Length: 1043'
i Ditch Length: 314'
/ C 1 Ditch Flow-1_ _ \
_ i
l
\ Culvert Drainage Area
% ( Area: 17.67 Ac.
\ I- Overland Length: 1043' =V-
\ Ditch Length:'314'
/ ��J ---c Dft h Flow�
I Grate Inlet Drainage Area
Area: 8.94 Ac. L ( / L
Overland Length: 54'
Ditch Length: 1669 > — \
South Ditch
Area: 3.72 Ac.
Overland Length: 45'
Ditch Length: 762'
DRAINAGE AREA MAP
®SCALE: Hor: 1" = 40'
0 20' 40' 80'
EXHIBIT "D"
POST DEVELOPED DRAINAGE AREA MAP
FOR PEAK FLOW ANALYSIS
GREAT OAKS, PHASES 13 r& if
COLLEGE STA7TON, BRAZOS COUNTY, TEXAS
EXHIBIT E
Technical Design Summary
Drainage Report
Great Oaks, Phases 13 & 14
t
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
The Cities of Bryan and College Station both require storm drainage design to follow these
Unified Stormwater Design Guidelines. Paragraph C2 of Section III (Administration) requires
submittal of a drainage report in support of the drainage plan (stormwater management plan)
proposed in connection with land development projects, both site projects and subdivisions.
That report may be submitted as a traditional prose report, complete with applicable maps,
graphs, tables and drawings, or it may take the form of a 'Technical Design Summary'. The
format and content for such a summary report shall be in substantial conformance with the
description in this Appendix to those Guidelines. In either format the report must answer the
questions (affirmative or negative) and provide, at minimum, the information prescribed in the
"Technical Design Summary" in this Appendix.
The Stormwater Management Technical Design Summary Report shall include several parts
as listed below. The information called for in each part must be provided as applicable. In
addition to the requirements for the Executive Summary, this Appendix includes several
pages detailing the requirements for a Technical Design Summary Report as forms to be
completed. These are provided so that they may be copied and completed or scanned and
digitized. In addition, electronic versions of the report forms may be obtained from the City.
Requirements for the means (medium) of submittal are the same as for a conventional report
as detailed in Section III of these Guidelines.
Note: Part 1 — Executive Summary must accompany any drainage report
required to be provided in connection with any land development project,
regardless of the format chosen for said report.
Note: Parts 2 through 6 are to be provided via the forms provided in this
Appendix. Brief statements should be included in the forms as requested,
but additional information should be attached as necessary.
Part 1 — Executive Summary Report
Part 2 — Project Administration
Part 3 — Project Characteristics
Part 4 — Drainage Concept and Design Parameters
Pan`. 5 — Plans and Specifications
Part 6 — Conclusions and Attestation
STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT
Part 1 — Executive Summary
This is to be a brief prose report that must address each of the seven areas listed below.
Ideally it will include one or more paragraphs about each item.
1. Name, address, and contact information of the engineer submitting the report, and
of the land owner and developer (or applicant if not the owner or developer). The
date of submittal should also be included.
2. Identification of the size and general nature of the proposed project, including any
proposed project phases. This paragraph should also include reference to
applications that are in process with either City: plat(s), site plans, zoning requests,
STORMWATER DESIGN GUIDELINES Page 1 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
• • - TECHNICAL DESIGN SUMMARY I
or clearing/grading permits, as well as reference to any application numbers or
codes assigned by the City to such request.
3. The location of the project should be described. This should identify the Named
Regulatory Watershed(s) in which it is located, how the entire project area is
situated therein, whether the property straddles a watershed or basin divide, the
approximate acreage in each basin, and whether its position in the Watershed
dictates use of detention design. The approximate proportion of the property in the
city limits and within the ETJ is to be identified, including whether the property
straddles city jurisdictional lines. If any portion of the property is in floodplains as
described in Flood Insurance Rate Maps published by FEMA that should be
disclosed.
4. The hydrologic characteristics of the property are to be described in broad terms:
existing land cover; how and where stormwater drains to and from neighboring
properties; ponds or wetland areas that tend to detain or store stormwater; existing
creeks, channels, and swales crossing or serving the property; all existing drainage
easements (or ROW) on the property, or on neighboring properties if they service
runoff to or from the property.
5. The general plan for managing stormwater in the entire project area must be
outlined to include the approximate size, and extent of use, of any of the following
features: storm drains coupled with streets; detention / retention facilities; buried
conveyance conduit independent of streets; swales or channels; bridges or culverts;
outfalls to principal watercourses or their tributaries; and treatment(s) of existing
watercourses. Also, any plans for reclaiming land within floodplain areas must be
outlined.
6. Coordination and permitting of stormwater matters must be addressed. This is to
include any specialized coordination that has occurred or is planned with other
entities (local, state, or federal). This may include agencies such as Brazos County
government, the Brazos River Authority, the Texas A&M University System, the
Texas Department of Transportation, the Texas Commission for Environmental
Quality, the US Army Corps of Engineers, the US Environmental Protection Agency,
et al. Mention must be made of any permits, agreements, or understandings that
pertain to the project.
7. Reference is to be made to the full drainage report (or the Technical Design
Summary Report) which the executive summary represents. The principal
elements of the main report (and its length), including any maps, drawings or
construction documents, should be itemized. An example statement might be:
"One -page drainage report dated , one set of
construction drawings (_sheets) dated and a
-page specifications document dated comprise
the drainage report for this project."
STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX, D: TECH, DESIGN SUMMARY
Effective February 2007 As Revised February 2009
APPENDIX
Part 2 — Project Administration
Start (Page 2.1)
Engineering and Design Professionals Information
Engineering Firm Name and Address:
Jurisdiction
City: Bryan
McClure & Browne Engineering/Surveying, Inc.
1008 Woodcreek Drive, Suite 103
X College Station
College Station, Texas 77845
Date of Submittal:
(979)693-3838
Lead Engineer's Name and Contact Info.(phone, e-mail, fax):
Other:
Jeffery L. Robertson, P.E.
Cullen L. Harper, E.I.T.
Supporting Engineering / Consulting Firm(s):
Other contacts:
Developer I Owner / Applicant Information
Developer / Applicant Name and Address:
Phone and e-mail:
Caldwell Companies
(???)
Property Owner(s) if not Developer / Applicant (& address):
Phone and e-mail:
Caldwell Companies
Project Identification
Development Name: Great Oaks Subdivision, Phase 13 & 14
Is subject property a site project, a single-phase subdivision, or part of a multi -phase subdivision?
Multi -phase Subdivision If multi -phase, subject property is phase 13&14 of 14
Legal description of subject property (phase) or Project Area:
(see Section ll, Paragraph B-3a)
Great Oaks Subdivision (224.534 Ac.), Phase 13(9.19 Ac.) & 14 (22.10 Ac.)
If subject property (phase) is second or later phase of a project, describe general status of all
earlier phases. For most recent earlier phase Include submittal and review dates.
Project is 13th and 14th phase of a 14 phase subdivision. At this time the first Phase has
been built. Phase 1 was submitted in September, 2000 and consists of 58 lots.
General Location of Project Area, or subject property (phase):
Project site is located approximately 4,000 feet to the northwest of the intersection of
Rock Prairie Road W. and Great Oaks Drive in College Station, Texas.
In City Limits?
Extraterritorial Jurisdiction (acreage):
Bryan: acres.
Bryan: College Station:
College Station: 31.29 acres.
Acreage Outside ETJ:
STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 2 — Project Administration
Continued (page 2.2)
Project Identification (continued)
Roadways abutting or within Project Area or
Abutting tracts, platted land, or built
subject property:
developments:
Walnut Rd. & Arboleda Dr.
Holt Hills Subdivision 261/887 (Platted)
M.S. Kavanaugh 437/581 (Not Platted)
Caldwell Companies., Phase 1
Named Regulatory Watercourse(s) & Watershed (s):
Tributary Basin(s):
Hopes Creek
Unnamed Tributary
Plat Information For Project or Subject Property (or Phase)
Preliminary Plat File #:
Final Plat File #: Date:
Name: Pending Approval
Status and Vol/Pg: Pending Approval
If two plats, sec
Status:
Zoning Information For Project or Subject Property (or Phase)
Zoning Type: PD-H (224.53 ac.) Existing or Proposed? Existing Case Code:
Case Date Status:
Zoning Type: Existing or Proposed? Case Code:
Case Date Status:
Stormwater Management Planning For Project or Subject Property (or Phase)
nning Conferences) & Date(s):
Participants:
Preliminary Report Require Submittal Date eview Date
Review Comments Addressed? Yes No_ InWr" g? When?
Compliance With Preliminary Drainage R rt, efly describe (or attach documentation
explaining) any deviation(s) from provisions of P Mary Drainage Report, if any.
STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 2 — Project Administration
Continued (page 2.3)
Coordination For Project or Subject Property (or Phase)
Note: For any Coordination of stormwater matters indicated below, attach documentation
describing and substantiating any agreements, understandings, contracts, or approvals.
De t.
Contact:
Date:
Subject:r
nts of
on
E
n or
atio
Coordination With
marize needs) & actions taken (include contacts & dates):
Non jurisdiction
City Needed?
Yes _ No x
Coordination with
Summarize needs actions taken (include contacts ates):
Brazos County
Needed?
Yes _ No x
Coordination with
Summarize need(s) & actions take in de contacts & dates):
TxDOT Needed?
Yes _ No x
Coordination with
Summarize ne s) &actions taken (include contacts & da
TAMUS Needed?
Yes No x
Permits For Project or Subject Property (or Phase)
As to stormwater management, are permits required for the proposed work from any of the entities
listed below? If so, summarize status of efforts toward that objective ins aces below.
Entity
Permitted or
Status of Actions (include dates)
A '
Approved .
US Army Crops of
Engineers
No x Yes _
US Environmental
Protection Agency
No x Yes
Texas Commission on
A Stormwater Pollution Prevention Plan must be
Environmental Quality
implemented prior to the start of construction
No _ Yes x
according to TPDES General Permit No. TXR150000.
Brazos River
Authority
No x Yes
STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 3 — Property Characteristics
Start (Page 3.1)
Nature and Scope of Proposed Work
Existing: Land proposed for development currently used, including extent of impervious cover?
Existing undeveloped land (Dense tree cover). Existing impervious cover is
approximately 0 sf.
Site
evelo ment of one platted lot, or two or more adjoining lat S.
Development
— Building on a latted lot of undeveloped I
Project
Building on two or more a — g �_ d' ' ' ots of undeveloped land.
select all
applicable
applicable)
— Building on a single adjoining lots, ro osed plat will not form
a new stre may include ROW dedication to e ' streets).
er (explain):
Subdivision
x Construction of streets and utilities to serve one or more platted lots.
Development
_ Construction of streets and utilities to serve one or more proposed lots on
Project
lands represented by pending Plats.
Site Projects: building use(s), approximate floor space, impervious cover ratio.
Describe
Subdivisions: number of lots by general type of use, linear feet of streets and
Nature and
drainage easements or ROW.
Size of
The phases of the subdivision includes 18 lots. The development
Proposed
consists of approximately 2400 LF of streets with 16' PUE on each
Project
side of the streets ROW.
Ex. I.C.=0 sf (Ok); Pr. I.C.= 61,500 sf (5%)
Is any work planned on land that is not Platted
lain:
or on land for which platting is not Pending?
x No Yes
FEMA Floodplains
Is any part of subject property abutting a Named Regulatory Watercourse
(Section II, Paragraph 81) or a tributary thereof?
No x Yes
Is any part of subject property in floodplain
area of a FEMA-regulated watercourse?
No x Yes Rate Ma 46041CO305E
p
Encroachment(s)
into Floodplain
Encroac urpose(s): — Building site(s) — Roa ng(s)
areas planned?
— Utility crossing(s) ther (ex1 '
No x
Yes
areas not shown on Rate Maps, has work been done toward amending the F
approved Floo efine allowable encroachments in proposed ar ain.
STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
b SECTION IX
I I APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 3 — Propertv Characteristics
Continued (Page 3.2)
Hydrologic Attributes of Subject Property (or Phase)
Has an earlier hydrologic analysis been done for larger area including subject property?
Yes
Reference the study (& date) here, and attach copy if not already in City files.
x
Great Oaks Subdivision; September, 2000
Is the stormwater management plan for the property in substantial conformance with the
earlier study? Yes x No If not, explain how it differs.
No
-If-subject property is not part of multi -phase project, describe stormwater manageme
plan for roperty in Part 4.
If property is pa Iti-phase project, provide overview of storm management plan
for Project Area here. In 4 describe how plan for sub' operty will comply
therewith.
Do existing topographic features on subject property store or detain runoff? x No Yes
_
Describe them (include approximate size, volume, outfall, model, etc).
Any known drainage or flooding problems in areas near subject property? x No Yes
Identify:
Based on location of study property in a watershed, is Type 1 Detention (flood control) needed?
(see Table B-1 in Appendix B)
Detention is required. x Need must be evaluated. _ Detention not required.
What decision has been reached? By whom?
Detention study performed by McClure & Browne during Phase 1.
If the need for
How was determination made?
Type Detention
Detention was required and is provided for the entire
must be evaluated:
Great Oaks Subdivision. However, Phases 13 & 14 do not require
any additional detention.
STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 3 — Property Characteristics
Continued (Page 3.3)
Hydrologic Attributes of Subject Property (or Phase) (continued)
Does subject property straddle a Watershed or Basin divide? x No Yes If yes,
describes Iits below. In Part 4 describe design conce t for handling this.
Watershed or Basin
Larger acreage
Less e
Above -Project Areas(Section II, Paragraph B3-a)
Does Project Area (project or phase) receive runoff from upland areas? _ No x Yes
Size(s) of area(s) in acres: 1) 1.1 ac. 2) 3) 4)
Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable
concentrated section(s), small creek (non -regulatory), regulatory Watercourse or tributary);
Phase 13 receives overland sheet from the north.
Flow determination: Outline hydrologic methods and assumptions:
The Rational Method was used for flow calculations and the post development
land was treated as large acre residential tracts.
Does storm runoff drain from public easements or ROW onto or across subject property?
x No _ Yes If yes, describe facilities in easement or ROW:
Are changes in runoff characteristics subject to change in future? Explain
No upstream land is already developed.
Conveyance Pathways (Section II, Paragraph C2)
Must runoff from study property drain across lower properties before reaching a Regulatory
Watercourse or tributary? x No Yes
Describe length and characteristics of each conveyance pathway(s). Include ownership of
property(ies).
STORMWATER DESIGN GUIDELINES Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 3 — Property Characteristics
Continued (Page 3.4)
Hydrologic Attributes of Subject Property (or Phase) (continued)
Conveyance Pathways (continued)
Do drainage
as, for what part of length? % Created by? plat, or
easements
_
instrument. If instrument(s), describe their provisions.
exist for any
part of
pathway(s)?
x No
Yes
Where runoff must cross lower pNperties, describe charac istics of abutting lower
property(les). (Existing watercourse Easement or Co ant squired?)
Pathway
Areas
Describe any built or impr d drainage facilities existing nea a property (culverts,
bridges, lined channels uried conduit, swales, detention ponds, tc).
Nearby
Drainage
Facilities
Do any of these have hydrologic or hydraulic influence on proposed stormwater
design? x No _Yes If yes, explain:
STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: TECH, DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Desian Parameters
Start (Page 4.1)
Stormwater Management Concept
Discharge(s) From Upland Area(s)
-MvwoQff is to be received from upland areas, what design drainage features will be used t
accomm it and insure it is not blocked by future development? Describe fo area,
flow section, or i e point.
Discharge(s) To Lower Property(ies) (Section II, Paragraph E1)
Does project include drainage features (existing or future) proposed to become public via
platting? x No _ Yes Separate Instrument? x No Yes
er Guidelines reference above, how will
Establishing Easements (Scenario 1)
ru ff be discharged to neighboring
pre -development Release (Scenar' )
prop (ies)?
Combination of the two Scenar!
Scenario . If easements are proposed, describe where needed, and provide stat of actions
on each. (Att ed Exhibit #_)
Scenario 2: Provide general de Option of how release(s) wil a managed to pre -development
conditions (detention, sheet flow, p !ally concentrated, et .. (Attached Exhibit #___)
Combination: If combination !s propdsed, explain how dIKharge will differ from pre -
development conditions at the pr erty line for each area (o oint) of release.
If Scenario 2, o ombination are to be used, has proposed design been coot ' ated with
owner(s) of r eiving property(ies)? No _ Yes Explain and pro ' e
documen ion.
STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainaae Concept and Desian Parameters
Continued (Page 4.2)
Stormwater Management Concept (continued)
Within Proiect Area Of Multi -Phase Project
' gaining Basins or Watersheds and acres shifting:
Will project result
in shifting runoff
between Basins or
What design and mitigation is us a pensate for increased runoff
between
Watersheds?
from gaining basin orwatersh
x No
Yes
How will runoff from Project
1. — With facility(ies) involving other development projects.
Area be mitigated to pre-
2 Establishing features to serve overall Project Area.
development conditions?
—
Select any or all of 1, 2,
3. x On phase (or site) project basis within Project Area.
and/or 3, and explain below.
red facilit (type & location of facility; design drainage area served; relationship to si
Project • Attached Exhibit #_)
2. For Overall Project Area (type & loc ' of facili 1 Attached Exhibit #---)
3. By phase (or site) oroiect: Describe planned mitigation measures for phases (or sites) in
subsequent questions of this Part.
aquatic echosystems proposed? No —Yes In which phase(s) or
proje ?
a
CC
Are other Best Manag nt Practices for reducing stormwate lutants proposed?
a
No —Yes Su size type of BMP and ent of use:
y
C
0)
O O
Z
of any runoff-handli cilities deviate from isions of B-CS Technical
xlE
�n
tions, check ty acility(ies) and explain in later q ons.
m
etention ents Conduitelements Cha Ifeatures
w Ditches Inlets Valley guttersuIVertfeatures
— Bridges Other
STORMWATER DESIGN GUIDELINES Page 11 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.3)
Stormwater Management Concept (continued)
Within Protect Area Of Multi -Phase Project (continued)
Will Project Area include bridge(s) or culvert(s)? _ No x Yes Identify type and
general size and In which phase(s).
A 42" culvert will pass under Arboleda Dr.
' /retention serves (will serve) overall Project Area, describe how it relates
phase or site p sical location, conveyance pathway(s), constru quence):
Within Or Serving Subject Property (Phase, or Site)
of larger Project Area, is design in substantial conform i earlier analysis
7art
a? Yes No, then raze the difference(s):
Identify whether each of the types of drainage features listed below are included, extent of use,
and general characteristics.
Typical shape?
Surfaces?
�•
a
V-shape
Grass
0
Steepest side slopes:
Usual front slopes:
Usual back slopes:
y Y
N
4:1
4:1
4:1
x
Flow line slopes: least o • Asa
Typical distance from travelway: 121
typical 1. soz greatest 1.75$
(Attached Exhibit #_)
o
y Z
r0
°
Are longitudinal culvert ends in compliance with B-CS Standard Specifications?
x Yes No, then explain:
rsections or otherwise, do valley gutters cross arterial or collector stre
g o-.
Yes If yes explain:
e �
I
w )
Are valley gutters proposed to cross away from an intersection?
rn z°
—No _Yes Explain, er of loca
y v
m xl
Q
STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.4)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
tter line slopes: Least Usual Greatest
Are I ets recessed on arterial and collector streets? _ Yes _ No "no",
identify here and why.
Will inlets captu 10-year design stormflow to prevent flooding of • tersections (arterial
with arterial or coll or)? _ Yes _ No If no, expl ' where and why not.
o.
0
3
Will inlet size and placemen revert exceeding allowaXe water spread for 10-year
a)
design storm throughout site ( hase)? Y No If no, explain.
_
rn
°'
Sag curves: Are inlets placed at low poi Yes No Are inlets and
conduit sized to prevent 100-year storm omponding at greater than 24 inches?
r
_ Yes _ No Explain "ng" answe
am
m
N
Will 100-yr stormflow b ontained in combination of ROW aN buried conduit on
'be
whole length of all st eis? Yes No If no, des where and why.
for curb, gutter, and inlets comply with B-CS Technical Specific 'ons?
7desig
as No If not, describe difference(s) and attach justification.
Are any 12-inch laterals used? X No Yes Identify length(s) and where
used.
r.
N
Pipe runs between system
Typical NA Longest 371
0
access points (feet):
xl
Are junction boxes used at each bend? _Yes x No If not, explain where
N
and why.
All storm drain Systems are straight runs.
�Z
a
E
°
Are downstream soffits at or below upstream soffits?
Least amount that hydraulic
Yes x No If not, explain where and why:
grade line is below gutter line
(system -wide):
#.##' (10 yr)
L1 STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.5)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Describe watercourse(s), or system(s) receiving system discharge(s) below
(include design discharge velocity, and angle between converging flow lines).
U
1) Watercourse (or system), velocity, and angle?
W
C
unnamed Tributary to Hopes Creek
Velocity 14 fps
O
Angle 65 degrees.
E
2) Watercourse (or system), velocity, and angle?
� a
o Ido
N3)
Watercourse (or system), velocity, and angle?
a
�v
O
o
a o.
E Z
For each outfall above, what measures are taken to prevent erosion or scour of
Nreceiving
and all facilities at juncture?
N
1) Rock Rip Rap at discharge into tributary.
(0
m
a
2)
N
N
0
3)
swale(s) situated along property lines between properties? _ No
Num r of instances: For each instance answer the following questio
Surface tr ments (including low -flow flumes if any):
r,
u,
m
a)
0 }
Flow line slopes (minimum maximum):
a
0
N z
Outfall characteristics for each (veto ' , convey tangle, & end treatment).
N
N X
l0
3
N
UJ
<
Will 100-year desi storm runoff be contained within easements r platted drainage
ROW in all inst ces? Yes No If "no" explain:
STORMWATER DESIGN GUIDELINES Page 14 of26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.6)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Are roadside ditches used? No X Yes If so, provide the following:
L
Is 25-year flow contained with 6 inches of freeboard throughout ? X Yes No
_
Are top of banks separated from road shoulders 2 feet or more? X Yes No
_
Are all ditch sections trapezoidal and at least 1.5 feet deep? _ Yes X No
N
For any "no" answers provide location(s) and explain:
m
All Ditches are V-shaped and at least 2' deep
0
conduit is beneath a swale, provide the following information (each instance).
Inslence 1 Describe general location, approximate length:
Is 100-ye design flow contained in conduit/swale combination? —Ye _ No
If "no" expl '
w^
U
o m
Space for 100-ye r storm flow? ROW Easement th
Z =_
Swale Surface ty , minimum
ConduitType and size, minim and maximum
x m
and maximum slopes:
slopes, design storm:
C
O
m
Inlets Describe how condui 's loaded (from streets/stor drains, inlets by type):
C C
l0 N
L
U
O
C
0 o
Access Describe how maintenance cess is p vided (to swale, into conduit):
Z is
0
2 o
m
Instance 2 Describe general location, ppro ' ate length:
a E
m m
w ur
3
v
Is 100-year design flow containe in conduit/swale c bination? —Yes —No
0 o
If "no" explain:
n
E r
Space for 100-year storm ow? ROW _ Easement Width
o N
Swale Surface type, nXhimurn
I Conduit Type and size, mi ' um and maximum
and maximum slope -lopes,
slopes, design storm:
CO
7
Inlets Describe ow conduit is loaded (from streets/storm drains, inl by type):
3 0
N
T
Access escribe how maintenance access is provided (to swale, into cond
STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.7)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
"yes" provide the following information for each instance:
Inst ce 1 Describe general location, approximate length, surfacing:
c
n
o
W
w=
+- ;
Is 100-year design w contained in swale? Yes No Is swale wholly
>°
_
within drainage ROW, Yes No Explain "no" swers:
m
5
Access Describe how mainte nce access is provid
o
Z
a
c g
0
Instance 2 Describe general location, ap ximate length, surfacing:
v
v
c a•
c
v
oo E
s o
design ff? co No s Swale wholly
n Swale?No
�d
`o
withi a War age R Yesed
Expe"n�rs:ains
_
�0
N p
W
Access Descr' how maintenance access is provided:
U
d
Ins nce 3 4 etc. If swales are used in more than two instances, attach sheet
,providing all above information for each instance.
w" channels: Will any area(s) of concentrated flow be channelized (deepened
wide or straightened) or otherwise altered? No Yes If only ' tly
shaped, s "Swales" in this Part. If creating side banks, provide informati elow.
a)
Will design reph a natural channel? Yes No If "no" each instance
o nLieion
sha & area, flow line slope (min. s max.), s ces, and 100-year
o 'ujnd
amount reeboard:
w
a
0
E
0
o
o
Z
X
m
U
STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.8)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
\Existina channels small creeks): Are these used? _ No _ Yes
I "yes" provide the information below.
Wi small creeks and their floodplains remain undisturbed? Yes _ No How
man disturbance instances? Identify each planned location:
For each Ioc tion, describe length and general type of proposed impro ment
(including floo lain changes):
For each location, des ibe section shape & area, flow line sl a (min. & max.),
surfaces, and 100-year sign flow.
a
w
c
oWatercourses
(and tributariesh Aqide from fri a changes, are Regulatory
Watercourses proposed to be altered o Yes Explain below.
_
Submit full report describing proposed c n s to Regulatory Watercourses. Address
E
existing and proposed section size and sh e, surtaces, alignment, flow line changes,
length affected, and capacity, and provid f documentation of analysis procedures
a
and data. Is full report submitted? No If "no" explain:
E
_
m
c
c
UAll
Proposed Channel Work: or all proposed chan I work, provide information
requested in next three boxe .
If design is to replicate nat al channel, identify location aN length here, and describe
design in Special Design ection of this Part of Report.
Will 100-year flo be contained with one foot of freeboard? _ Y No If
_
not, identify loc ion and explain:
Are R / easements sized to contain channel and required maintenance spa e?
es _ No If not, identify location(s) and explain:
STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.9)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
ow many facilities for subject property project? For each provide info. belo
F each dry -type facilkiy:
Facility 1
Facility 2
Acre served & design volume + 10%
100-yr olume: free flow & plugged
Design di barge (10 yr & 25 yr)
Spillway cre at 100-yr WSE?
_ yes no
_ y s _ no
Berms 6 inche above plugged WSE?
_yes _ no
yes _ no
Explain any "no" savers:
N
N
}
For each facility what is 25- design Q, and design of ou t structure?
Facility 1:
0
zl
Facility 2:
x
Do outlets and spillways discharge i to a public f ility in easement or ROW?
Facility 1: —Yes —No Facilit 2: —Yes —No
If "no" explain:
0
0
0
0
a.
For each, what is velocity of 25-yr desl disch rge at outlet? & at s ilo Iwav?
Facility 1: & Fad' 2: &
Are energy dissipation measures ed? No Yes Describe type and
ca
u-
_
location:
c
0
c
0
m
O
a)
For each, is spillwZsuce treatment other than concrete? es or no, and describe:
Facility 1:
Facility 2:
For each, what easures are taken to prevent erosion or scour at rec 'ving facility?
Facility 1:
Facility 2:
If berm re used give heights, slopes and surface treatments of sides.
Faciii 1:
/acility 2:
STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.10)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
ructures comply with B-CS Specifications? Yes or no, and explain if "no":
Facility 1;
m
LL
Facility 2:
o '.
o C
0
o
For additional faciliti ovide all same information on a sepa sheet.
Are parkin as to be used for detention? No
_Yes
ma " m depth due to required design storm?
Roadside Ditches: Will culverts serve access driveways at roadside ditches?
No X Yes If "yes", provide information in next two boxes.
Will 25-yr, flow pass without flowing over driveway in all cases? X Yes _ No
Without causing flowing or standing water on public roadway? X Yes _ No
Designs & materials comply with B-CS Technical Specifications? x Yes _ No
Explain any "no" answers:
C1•
N
m
C
o
Are culverts parallel to public roadway alignment? X Yes _ No Explain:
U �
N }
ca
x I
o
Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
m
ways that serve Above -Project areas or are in public easements/ ROW?
o
mz
_No X Yes If "yes" provide information below.
N
How many instances? X Describe location and provide information below.
a)
Location 1: The 42" Culvert will serve some upland areas.
U
Location 2:
Q
Location 3:
For each location enter value for:
1
2
3
Design year passing without toping travelway?
100
Water depth on travelway at 25-year flow?
0"
Water depth on travelway at 100-year flow?
0"
For more instances describe location and same information on separate sheet.
STORMWATER DESIGN GUIDELINES Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
Part 4 — Drainaae Concept and Design Parameters
Continued (Page 4.11)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Named Regulatory Watercourses I& Tributaries): Are culverts proposed on these
facilities? X No Yes, then provide full report documenting assumptions,
criteria, analysis, computer programs, and study findings that support proposed
design(s). Is report provided? Yes _ No If "no", explain:
Arterial or Maior Collector Streets: Will culverts serve these types of roadways?
s
X No Yes How many instances? For each identify the
a)
location and provide the information below.
a m
Instance 1:
r o.
w
Instance 2:
x c
o
Instance 3:
c
0
o 'q
Yes or No for the 100-year design flow:
1
2
3
z
E
o
Headwater WSE 1 foot below lowest curb top?
c
m
Spread of headwater within ROW or easement?
E
Is velocity limited per conditions (Table C-11)?
mExplain
any "no" answer(s):
o c
U
T @
(p U
3 0
a
o
o s
Minor Collector or Local Streets: Will culverts serve these types of streets?
No X Yes How many instances? 1 for each identify the
location and provide the information below:
m n
Instance 1: 42" Culvert crosses Arboleda Dr.
(D c
Instance 2:
o
Instance 3:
(D y
For each instance enter value, or "yes" / "no" for:
1
2
3
Design yr. headwater WSE 1 ft. below curb top?
Yes
c
'a)
100-yr. max. depth at street crown 2 feet or less?
Yes
E
Product of velocity (fps) & depth at crown (ft) = ?
Yes
Is velocity limited per conditions (Table C-11)?
Yes
Limit of down stream analysis (feet)?
Yes
Explain any "no" answers:
STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
;)ECTION IX
aMKII I
.
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4,12)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
All Proposed Culverts: For all proposed culvert facilities (except driveway/roadside
ditch intersects) provide information requested in next eight boxes.
Do culverts and travelways intersect at 90 degrees? X Yes No If not,
identify location(s) and intersect angle(s), and justify the design(s):
Does drainage way alignment change within or near limits of culvert and surfaced
approaches thereto? X No _ Yes If "yes" identify location(s), describe
change(s), and justification:
Are flumes or conduit to discharge into culvert barrel(s)? X No —Yes If yes,
identify location(s) and provide justification:
Are flumes or conduit to discharge into or near surfaced approaches to culvert ends?
No X Yes If "yes" identify location(s), describe outfall design treatment(s):
c
Concrete flumes are provided on each side of Arboleda Dr. to prevent erosion.
C
O
U
U)
Is scour/erosion protection provided to ensure long term stability of culvert structural
ci
components, and surfacing at culvert ends? x Yes _No If "no" Identify
locations and provide justif ication(s):
Will 100-yr flow and spread of backwater be fully contained in street ROW, and/or
drainage easements/ ROW? X Yes _ No if not, why not?
Do appreciable hydraulic effects of any culvert extend downstream or upstream to
neighboring land(s) not encompassed in subject property? X No Yes If
_
"yes" describe location(s) and mitigation measures:
Areallculvert designs and materials in compliance with B-CS Tech. Specifications?
_ Yes _ No If not, explain in Special Design Section of this Part.
STORMWATER DESIGN GUIDELINES Page 21 of26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D ® TECHNICAL DESIGN SUMMARY
Part 4 — Drainaae Concept and Desian Parameters
Continued (Page 4.13)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
bridge included in plans for subject property project? _ No —Yes
If "ye " rovide the following information.
Name(s) a functional classification of the roadway(s)?
What drainage ways) is to be sad?
N
N
01
a
m`
A full report supporting "Pacts of the proposed bridge(s tructural, geotechnical,
hydrologic, and hydr is factors) must accompany this summa ort. Is the report
provided? as _ No If "no" explain:
Is a Stormwater
Provide a general description of planned techniques:
T
Pollution Prevention
Silt fence and inlet filtration will serve as the
Plan (SW3P)
main protection against stormwater pollution. The
C1
m
established for
project construction?
Contractor shall use any other means necessary
m
throughout construction.
3:
No x Yes
Special Designs — Non -Traditional Methods
Are any non-traditional methods (aquatic echosystems, wetland -type detention, natural stream
replication, BMPs for water quality, etc.) proposed for any aspect of subject property project?
x No —Yes If "yes" list general type and location below.
ull report about the proposed special design(s) including rationale for use and
expected be Report must substantiate that stormwater management as will not
be compromised, an intenance cost will not exceed thos itional design
solution(s). Is report provided? _Yes no' explain:
STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.14)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
eclal Designs — Deviation From B-CS Technical Specifications
If a design(s) or material(s) of traditional runoff -handling facilities deviate from provisions of
B-CS chnical Specifications, check type facility(ies) and explain by specific detail eleme
De tion elements _ Drain system elements _ Channel features
Culve atures _ Swales _Ditches _ Inlets tfalls
Valley gut s _ Bridges (explain in bridge report)
In table below briefly r ntify specific element, justification for deviation(s).
Specific Data Eleme
Justification for Deviation (attach add' ' nal sheets if needed)
1)
2)
3)
4)
5)
7Z
Have elements been co,Qfdinated with the City Engineer or her/his des ee? For each item
no", action date, and staff name:
Z
Design Parameters
Hydrology
Is a map(s) showing all Design Drainage Areas provided? x Yes No
Briefly summarize the range of applications made of the Rational Formula:
For the Rational Formula we assumed residential areas had a
runoff coefficient of 0.5 for large residential lots.
What is the size and location of largest Design Drainage Area to which the Rational Formula
has been applied? 17 * 7 acres Location (or identifier): 4 s ° Arboleda Dr. Culvert
i V STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.15)
Design Parameters (continued)
Hydrology (continued)
In making determinations for time of concentration, was segment analysis used?
x No _ Yes In approximately what percent of Design Drainage Areas? %
As to intensity -duration -frequency and rain depth criteria for determining runoff flows, were any
criteria other than those provided in these Guidelines used? x No _Yes If "yes"
identify type of data, source(s), and where applied:
For each of the stormwater management features listed below identify the storm return
frequencies (year) analyzed (or checked), and that used as the basis for design.
Feature
Analysis Year(s)
Design Year
Sto ' s stem for arterial and collector streets
Storm drain system for ets
Open channels
Swale/buried conduit co n in Iieu of channel
Swa
Roadside ditches and culverts serving them
2, 5, 10, 25, 50, 100
25
De acilities: spillway crest and its outfall
Detention faciliti6Zand conveyance structure(s)
Detention facilities: volume when ou ed
Culverts serving private drives or str
Culverts serving pu ways
Bri rovide in bridge report.
Hydraulics
What is the range of design flow velocities as outlined below?
Design flow velocities;
Gutters
Conduit
Culverts
Swales
Channels
Highest (feet per second)
###
Lowest (feet per second)
###
Streets and Storm Drain Systems Provide the summary information outlined below:
Roughness coefficients used: For street gutters: NA
For conduit type(s) RCP 0. 013 HDPE 0.013 Coefficients:
STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Desian Parameters
Continued (Page 4.16)
Design Parameters (continued)
Hydraulics (continued)
Street and Storm Drain Systems (continued)
For the following, are assumptions other than allowable per Guidelines?
Inlet coefficients? X No _Yes Head and friction losses X No _Yes
Explain any "yes" answer:
In conduit is velocity generally increased in the downstream direction? X Yes _ No
Are elevation drops provided at inlets, manholes, and junction boxes? X Yes _ No
Explain any "no" answers:
Are hydraulic grade lines calculated and shown for design storm? _ Yes x No
For 100-year flow conditions? X Yes _ No Explain any "no" answers:
Hydraulic grade lines are calculated but not shown.
What tailwater conditions were assumed at cutfall point(s) of the storm drain system? Identify
each location and explain:
Both storm sewer designs assumed the pipes were full for tailwater conditions.
in Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a? Yes
Outside straight sections, is flow regime within limits of sub -critical flow? _ Ye _ No
If "no" list Io ions and explain:
Culverts If plan sheets do-lWt provide the following for each c rt, describe it here.
For each design discharge, will op tion be outlet (barrel ntrol or inlet control?
Entrance, friction and exit losse
Brid Provide all in bridge report
STORMWATER DESIGN GUIDELINES Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
_-- DESIGN
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.17)
Design Parameters (continued)
Computer Software
What computer software has been used in the analysis and assessment of stormwater
management needs and/or the development of facility designs proposed for subject property
project? List them below, being sure to identify the software name and version, the date of the
version, any applicable patches and the publisher
Open Office Calculator Spreadsheet
Hydraflow Express Extension for AutOCAD Civil 3D 2012
Part 5 — Plans and Specifications
Requirements for submittal of construction drawings and specifications do not differ due to use of a
Technical Design Summary Report. See Section III, Paragraph C3.
Part 6 — Conclusions and Attestation
Conclusions
Add any concluding information here:
The Great Oaks Subdivision, Phases 13 & 14 will have no adverse impact to downstream
properties and conforms to the overall subdivision report.
Attestation
Provide attestation to the accuracy and completeness of the foregoing 6 Parts of this Technical
Design Summary Drainage Report by signing and sealing below.
"This report (plan) for the drainage design of the development named in Part B was prepared
by me (or under my supervision) in accordance with provisions of the Bryan/College Station
Unified Drainage Design Guidelines for the owners of the property. All licenses and permits
required by any and all state and federal regulatory agencies for the proposed drainage
improvements have been issued or fall under applicable general permits."
(Affix Seal) �t �•o... TC I gS3ta!
d�
o _ .....
Lice L. R06ERTSOh..
ed Prof, sional Engineer i JEFFERY
/...........
,94745 •�11
State of Texas PE No, I Lf �t®81o9Qc ENs �•�_�
Czr
,4
STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009