HomeMy WebLinkAboutDrainage ReportDetention Pond
Drainage Report
for
A New Laboratory and Office Facility for TDI/Brooks International
South Dowling Road
Brazos County, Texas
January,2012
Engineer.•
SCHULTZ ENGINEERING LLC
TBPE Firm Registration No. 12327
P.O. Box 11995
College Station, TX 77842
2730 Longmire Drive
College Station, Texas 77845
(979) 764-3900
Developer.
TDI/Brooks International
1902 Pinon
College Station, Texas 77842
(979)693-3446
Detention Pond
Drainage Report
For
A New Laboratory and Office Facility for TDUBrooks International
ENGINEER
SCHULTZ ENGINEERING LLC
P.O. Box 11995
College Station, Texas 77842
Phone/Fax: (979)764-3900
GE03,Inc.
1902 Pinon
College Station, Texas 77845
Phone: (979) 693-3446
GENERAL DESCRIPTION AND LOCATION
Location:
This project is located on a 52 acre tract of land located at the north east
corner of the intersection of IG&N Road and South Dowling Road in
Brazos County. The tract is Block 1, Lot 1, TDI-Brooks International
Center.
Description:
• Area:
52 acres
• Proposed Land Use:
Commercial — Laboratory and Office Facilities
• Existing Land Use:
Vacant - Agricultural
• Land Description:
The ground slopes toward the southwest to IG&N Road.
Adjoining Land Use:
The site is bounded on the north and east by rural residential properties,
on the west by IG&N Road and on the south by South Dowling Road.
Primary Drainage Facility:
Tributary of Peach Creek
Flood Hazard Information:
FEMA FIRM-
# 48041CO200 C
Floodplain:
No portion of this Phase lies within the floodplain of Peach Creek or its
tributaries.
HYDROLOGIC CHARACTERISTICS
This phase of the development of this property will be located on the southwest portion of the
property. This portion of the property drains to the southwest into the right-of-way of IG&N
Road. The pre -development condition of the land is pasture with some scattered large trees and a
wooded area where the pond is located. The topographic survey of the property identified a small
existing pond which collects the stormwater runoff from a small portion of the tract. Exhibit A
shows the existing, pre -development topography and the runoff flow direction.
Page I of 5
GENERAL STORMWAT_ER PLAN
The drainage plan for this development will involve the installation of private storm sewer pipes,
inlets, and ditches which will collect and transmit the runoff into the existing detention pond
previously constructed for this phase of the development. The detention pond will discharge
into the existing drainage way so that the runoff enters the IG&N Road right of way at the same
location as the pre -development condition. This development will increase the stormwater runoff
from this property. The detention pond was constructed for this development so that the post -
development peak discharge from this development will be equal to or less than the pre -
development flow onto the adjacent property. The detention pond will also be a retention pond
that permanently holds water so it can be used as an amenity.
COORDINATION & STORMWATER PERMITTING
The project will require that a Notice of Intent be submitted to the Texas Commission for
Environmental Quality. No other permits are anticipated for this project.
General:
There is an existing detention pond for this site. Refer to Exhibit B for
its location.
T, Methodology:
TR 55
T, Minimum
10 minutes
Design Storm Events:
2, 10, 25, 50 and 100-year storms— detention analysis
Pond Discharge
Pipe Materials:
Steel Pipe with smooth interior
Manning's n Value:
0.013
Runoff Curve
Number (CN):
CN=81 — undeveloped property, 0% Impervious,
CN=81 — developed property, 50% Impervious
Design Constraints:
Post Development flow less than or equal to Pre -Development flow
6" freeboard on pond berm for 100 year storm with outlet clogged
Design Software:
HEC-HMS, Excel spreadsheets, DODSON HydraCalc Hydraulics
The HEC-HMS software was used to compute the pre and post
development flow and the routing of the flow through the detention
ponds. The other programs are used to compute the pond storage and
discharge input data for the HEC-HMS program.
Applicable Exhibits:
Exhibit A - Pre Development Drainage Area Map
Exhibit B - Post Development Drainage Area Map
Exhibit C - Pond Design
Appendix A - Detention Pond elevation -storage data & elevation -
discharge data
Appendix B - HEC — HMS computer model output
Page 2 of 5
DESIGN ANALYSIS:
The pre- and post -development runoff information for the detention pond evaluation is shown in Table 1.
The pre -development drainage area is shown on Exhibit A. The HEC-HMS computer computes the peak
flow and it is shown in Table 2.
TABLE 1— Pre- & Post -Development Runoff Information — Detention Analysis
Area
#
Area
Acres
CN
%
Imp .
Tc
Min.
Lag
Min.
Pre
101
10.74
81
0
36.8
22.0
Post
201
10.92
81
50
25
18.0
The post -development drainage area is shown on Exhibit B. The HEC-HMS computer program routes
the runoff through the detention pond, and the resulting peak flows are shown in Table 2. The post -
development flows shown in Table 2 are for the currently proposed development. Additional
development of the site will require an evaluation to see if the peak flows after the additional
development are still less than the pre -development flows. A description of the detention pond outlet
structures, discharge pipes and overflow spillways is found in Appendix A.
TABLE 2 — Pre- & Post -Development Peak Discharge Comparison
Location
Q2
Q10
Q25
Q50
Q100
cfs
cfs
cfs
cfs
Cfs
Pre -
Development
14.7
31.4
38.8
44.8
50.3
@ Outfall
Post -
Development
1.3
14.0
22.1
31.6
40.9
thru Pond
Total @
Outfall
1.3
14.0
22.1
31.6
40.9
Decrease in
Peak Flow
13.4
17.4
16.7
1 13.2
9.4
As shown in Table 2, the post -development peak outflow at the outfall less than the allowable peak
outflow for each design storm event. Additionally, Table 3 presents the maximum water surface and the
amount of freeboard for the Detention Pond. The peak flow out of the detention ponds and the maximum
water surface was determined by the HEC-HMS program.
Page 3 of 5
TABLE 3 — Summary of Pond 2 Maximum Water Surface Levels
Storm
Event
Water
Surface
Elevation,
ft
Flow Thru
Overflow
Spillway cfs
Freeboard
ft.
Velocity in
Overflow
Spillway, fps
Velocity
Downstream
of Overflow
Spillway, fps
2-year
323.6
0
1.80
0
0
10-year
324.3
11.9
1.00
2.0
2.6
25-year
324.5
19.9
0.90
2.4
3.2
50-year
324.6
29.1
0.70
2.7
3.7
100-year
324.7
38.3
0.60
3.0
4.1
The pond has an overflow spillway which discharges when the outlet structure cannot handle all of the
discharge. This spillway will be a 15' wide channel, grass lined and have a flat crest at elevation 324.
The spillway is also used if the outlet structure is clogged. The HEC-HMS model was run with the
outlet clogged and the maximum water surface determined for the pond. The results were a water
surface elevation of 324.7, which results in more than 6" of freeboard still provided in the pond.
The grading plan for the detention pond and the pond discharge pipe details are shown in the Exhibit C.
The pond discharge pipe is an 8" steel siphon pipe.
The detention pond for the TDI-Brooks Laboratory and Office Buildings was designed and constructed
prior to annexation of the property.
The design of the existing detention pond does not comply with the BCS Stormwater Design
Guidelines, Section VI, E, 3, 6, 4, that requires the elevation of the weir crest to not be less than the
water surface elevation resulting from the design 100-year storm, assuming a fully operating discharge
structure. Typically this is not a requirement for ponds other than detention ponds. Generally, principal
spillway structures are designed to pass the pond discharge from all storms except for the 50 to 100 year
storm peak discharges. A principal spillway structure that will accomplish this is costly and requires
maintenance. The property owner has selected a siphon pipe discharge structure which will require less
maintenance cost. The overflow spillway will not discharge for a 2-year storm, but does have flow
through it for 10-year through 100-year storms. The discharge through the overflow spillway has been
added to Table 2 as well as the velocity in the spillway channel and downstream of the spillway. The
maximum computed velocity in the overflow spillway or downstream channel is 4.0 fps for the 100
year storm which is less than the 4.5 fps maximum design velocity for a grass lined channel. (Table C-
11 of BCS Design Guidlines). The property owner is aware that the overflow spillway may have to flow
through it occasionally and is willing to perform maintenance, if any, of the overflow spillway and the
area downstream of the spillway.
The embankment for the existing pond is 16' in height and the total pond storage capacity is
approximately 14 acre-feet. Since the height is less than 25', with a storage capacity less than 15 acre-
feet, Chapter 299 of the TCEQ Dam Safety Program does not apply.
Page 4 of 5
CONCLUSION
The drainage system and detention facility described in this report is designed in accordance with the
standards in the BCS Drainage Design Guidelines except as noted in this report. The pond is designed in
accordance with accepted engineering standards. The post development peak runoff flowrate into the
adjacent property will be less than the predevelopment flowrates for all storm events. The post
development runoff from this property for the 100-year storm event will not adversely affect the
properties just downstream of this property.
CERTIFICATION
"This report for the drainage design of A New Laboratory and Office Facility for TDI/Brooks
International, was prepared by me in accordance with the 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."
F-12327
SCHULTZ ENGINEERING, LLG.
�V
Joseph I.
Sch 1tz, P.E.
Page 5 of 5
APPENDIX A
Detention Pond Elevation -Storage Data
Elevation -Discharge Data
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I
TDIIBrooks Laboratory & Office Facility
Detention Pond Area -Capacity Data
V = H * ((A1+A2 + (A1*A2)"'I / 3)
V = volume, ft2
A = area,ft2
H = difference in elevation, ft
APPENDIX B
HEC-HMS
Computer Model Output
HEC-HMS
Pre -Development Peak Runoff
Project: Pond 2
Simulation Run: Pre 2 yr 12 yr Subbasin: DA101
Start of Run: 20Jan2O12, 08:00 Basin Model:
End of Run: 20Jan2O12, 20:00 Meteorologic Model:
Compute Time: 20Jan2O12, 09:23:58 Control Specifications:
Volume Units: IN
Peak Discharge:
14.7 (CFS)
Total Precipitation :
3.34 (IN)
Total Loss :
1.76 (IN)
Total Excess:
1.58 (IN)
Date/Time of Peak Discharge
Total Direct Runoff
Total Baseflow :
Discharge:
Pre Dev
2yr12hr
Storm
20Jan2O12, 14:30
1.56 (IN)
0.00 (IN)
1.56 (IN)
Project: Pond 2
Simulation Run: Pre 10yr 12hr Subbasin: DA101
Start of Run: 20Jan2O12, 08:00 Basin Model:
End of Run: 20Jan2012, 20:00 Meteorologic Model:
Compute Time: 20Jan2O12, 09:23:44 Control Specifications:
Volume Units: IN
mputed Results ----•---•-------
Pre Dev
10 yr 12 hr
Storm
Peak Discharge: Date/Time of Peak Discharge : 20Jan2O12, 14:25
Total Direct Runoff : 4.02 (IN)
Total Baseflow : 0.00 (IN)
Discharge: 4.02 (IN)
31.4 (CFS)
Total Precipitation :
6.22 (IN)
Total Loss :
2.13 (IN)
Total Excess:
4.08 (IN)
Project: Pond 2
Simulation Run: Pre 25yr 12 hr Subbasin: DA101
Start of Run: 20Jan2O12, 08:00 Basin Model:
End of Run: 20Jan2O12, 20:00 Meteorologic Model:
Compute Time: 20Jan2O12, 09:23:49 Control Specifications:
Volume Units: IN
Peak Discharge:
38.8 (CFS)
Total Precipitation :
7.42 (IN)
Total Loss:
2.22 (IN)
Total Excess :
5.19 (IN)
Date/Time of Peak Discharge
Total Direct Runoff
Total Baseflow :
Discharge:
Pre Dev
25 yr 12 hr
Storm
20Jan2O12, 14:25
5.12 (IN)
0.00 (IN)
5.12 (IN)
Project: Pond 2
Simulation Run: Pre 50yr 12 hr Subbasin: DA101
Start of Run: 20Jan2012, 08:00 Basin Model:
End of Run: 20Jan2O12, 20:00 Meteorologic Model:
Compute Time: 20Jan2012, 09:24:09 Control Specifications:
Volume Units: IN
Peak Discharge :
44.8 (CFS)
Total Precipitation :
8.45 (IN)
Total Loss:
2.28 (IN)
Total Excess:
6.17 (IN)
Date/Time of Peak Discharge
Total Direct Runoff
Total Baseflow :
Discharge:
Pre Dev
50 yr 12 hr
Storm
20Jan2O12, 14:25
6.07 (IN)
0.00 (IN)
6.07 (IN)
Project: Pond 2
Simulation Run: Pre 100 yr 12 hr Subbasin: DA101
Start of Run: 20Jan2O12, 08:00 Basin Model: Pre Dev
End of Run: 20Jan2012, 20:00 Meteorologic Model: 100 yr 12 hr
Compute Time: 20Jan2O12, 09:23:39 Control Specifications: Storm
Volume Units: IN
Peak Discharge:
50.3 (CFS)
Total Precipitation :
9.50 (IN)
Total Loss :
2.33 (IN)
Total Excess:
7.17 (IN)
Date/Time of Peak Discharge
Total Direct Runoff
Total Baseflow :
Discharge:
20Jan2012, 14:25
7.07 (IN)
0.00 (IN)
7.07 (IN)
HEC-HMS
Post -Development Peak Runoff and Pond Hydrographs
Project: Pond 2
Simulation Run: Post-2yr-12hr Reservoir: Pond2
Start of Run: 20Jan2012, 08:00 Basin Model: Post Dev
End of Run: 20Jan2012, 20:00 Meteorologic Model: 2 yr 12 hr
Compute Time: 20Jan2012, 09:16:50 Control Specifications: Storm
Volume Units: IN
Peak Inflow:
23.6 (CFS)
Peak Outflow:
1.3 (CFS)
Total Inflow:
2.44 (IN)
Total Outflow:
0.65 (IN)
Date/Time of Peak Inflow:
Date/Time of Peak Outflow
Peak Storage :
Peak Elevation
20Jan2012, 14:20
20Jan2012, 17:00
1.7 (AC -FT)
323.6 (FT)
Reservoir TondT Results for Run "Post-2yr-12ht'
00:00 10:00 12:00
2Wan2012
...... Run:Pos42yrr12hrElement:POND2Result:Storage
--- Run:PosF2yr-12hrElement:POND2Resu0:ComNnedFW
14:00 16:00 16.00 20:00
Run:Post-2yr-12hrElemedPOND2ResulCPool Elevation—Rudosh2yr12hrElement:POND2Resull.OuM
Project: Pond 2
Simulation Run: Post-10yr-12hr Reservoir: Pond2
Start of Run: 20Jan2012, 08:00 Basin Model: Post Dev
End of Run: 20Jan2012, 20:00 Meteorologic Model: 10 yr 12 hr
Compute Time: 20Jan2012, 09:16:39 Control Specifications: Storm
Volume Units: IN
Peak Inflow:
40.4 (CFS)
Peak Outflow:
14.0 (CFS)
Total Inflow:
5.09 (IN)
Total Outflow:
2.55 (IN)
Date/Time of Peak Inflow:
Date/Time of Peak Outflow
Peak Storage:
Peak Elevation
20Jan2012, 14:20
20Jan2012, 15:00
2.8 (AC -FT)
324.3 (FT)
Reservoir "Pond? Results for Run "Post-10yr-12hr"
I I
40...-_-
--
I ,
- _ _.
I
2s i_ �_._ .. _. _
_ � I - II I
.... I __ ..---_._— _
a 20 .- _ � y II _ .
I
I �
------- -- —
i
0--------------------------
08:00 10:00 12M 14:00 16:00 18:00 20:00
20Jan2012
•..... Run:PoklOp12hrElemenl:POND2Resdbrage -- Run:Post-10yr-12hrElement:POND2Resu#:PoolElevaWn — Run:Post-10yn12hrElement.POND2Resull:Oftw
--- Run:Past-10yr-12hr Element:POND2 Resua.Comhined Fhw
Project: Pond 2
Simulation Run: Post-25yr-12hr Reservoir: Pond2
Start of Run: 20Jan2012, 08:00 Basin Model: Post Dev
End of Run: 20Jan2012, 20:00 Meteorologic Model: 25 yr 12 hr
Compute Time: 20Jan2012, 09:16:44 Control Specifications: Storm
Volume Units: IN
Computed Results -------- -----
Peak Inflow: 48.1 (CFS)
Peak Outflow: 22.1 (CFS)
Total Inflow: 6.24 (IN)
Total Outflow: 3.68 (IN)
Date/Time of Peak Inflow:
Date/Time of Peak Outflow
Peak Storage:
Peak Elevation
20Jan2012, 14:20
20Jan2012, 14:50
3.0 (AC -FT)
324.5 (FT)
Reservoir "Pond2" Results for Run "Post-25yr•12hr"
08:00 10:00 12:Ou Woo MW
20Jan2012
----- Run:Post-25yr-12hrElement.PONO2ResultSlorage ---- Run:Post-25yr-12hrEemenl:POND2Resug:PoolEleva5on
--- Run:Post-25yo12hr Elemenl:POND2 Resug:Corn ined Flow
IDA
20:00
Run:Post-25yr-12hr Elemenl:PONO2 Result0u0bw
Project: Pond 2
Simulation Run: Post-50yr-12hr Reservoir: Pond2
Start of Run: 20Jan2012, 08:00 Basin Model: Post Dev
End of Run: 20Jan2012, 20:00 Meteorologic Model: 50 yr 12 hr
Compute Time: 20Jan2012, 09:16:55 Control Specifications: Storm
Volume Units: IN
Computed Results-------------�-
Peak Inflow: 54.4 (CFS)
Peak Outflow: 31.6 (CFS)
Total Inflow: T23(IN)
Total Outflow: 4.65 (IN)
Date/Time of Peak Inflow:
Date/Time of Peak Outflow
Peak Storage :
Peak Elevation
20Jan2012, 14:20
20Jan2012, 14:40
3.2 (AC -FT)
324.6 (FT)
Reservoir "Pond? Results for Run "Post-50yr-12hr"
-----Run:Post-5402hrElementP0N2Resdbrage -- Run'.Post-50yr-12hrElementPOND2Resu0:PWElevalbn —Run:Post-50yr-12hrElement:POND2Resul:Ou&w
--- Run:Post-50yr-12hrElement:POND2Resuh:Combinedfbw
Project: Pond 2
Simulation Run: Post-100-yr-12hr Reservoir: Pond2
Start of Run: 20Jan2012, 08:00 Basin Model: Post Dev
End of Run: 20Jan2012, 20:00 Meteorologic Model: 100 yr 12 hr
Compute Time: 20Jan2012, 09:15:11 Control Specifications: Storm
Volume Units: IN
Peak Inflow:
59.9 (CFS)
Peak Outflow:
40.9 (CFS)
Total Inflow:
8.25 (IN)
Total Outflow:
5.66 (IN)
Date/Time of Peak Inflow:
Date/Time of Peak Outflow
Peak Storage:
Peak Elevation
20Jan2012, 14:20
20Jan2012, 14:40
3.4 (AC -FT)
324.7 (FT)
Reservoir "Pond2" Results for Run 'Post-100-yr-12hr"
Run:Post-100-yr42hrElement.POND2ResdStorage --- Run:Post-I00-yr-12hrOementPOND2ResultPOWOeuton —Run:Post-iO-yr-12hrElementPONO2Resull:Outgow
Rua:Post-100-yr-12hr Element:POND2 ResultComEned Fbw
HEC-HMS
Post Development Peak Runoff and Pond Hydrographs
with Output Structure Clogged
Project: Pond 2
Simulation Run: Post- 1 00yr-Clogged Reservoir: Pond2
Start of Run: 20Jan2012, 08:00 Basin Model: Post Dev clogged
End of Run: 20Jan2012, 20:00 Meteorologic Model: 100 yr 12 hr
Compute Time: 20Jan2012, 09:16:32 Control Specifications: Storm
Volume Units: IN
Computed Results ----------------
Peak Inflow: 59.9 (CFS)
Peak Outflow: 42.2 (CFS)
Total Inflow: 8.25 (IN)
Total Outflow: 5.60 (IN)
Date/Time of Peak Inflow:
Date/Time of Peak Outflow
Peak Storage:
Peak Elevation
20Jan2012, 14:20
20Jan2012, 14:35
3.4 (AC -FT)
324.7 (FT)
EXHIBIT A
Pre -Development
Drainage Area Map
IL
X -�
LEGEND «q
---I mm, =now palm da -mom
f
�. 40� � 1
/,°�°
50 25 0 50�
SCALE IN FEET
�s DA 1 0 1
/r
.� 10.74`,,CRES
`4 "l000
\w
(W 11 fp t 7 ttj j T
/-
� �� � �.•.`.� fid' � '. � � /�• ,r"mom" � � t }t pt J S } 7 � � .� qfP;� Y......® "-'. s✓
e,
10
4000,
i --
A
o
7
�I
q
i
P jpa
'v
5.
3 " L
o POST 32'
,
t i 1 j �� {i\{\ 3, ,• ' �' - '` 30" POST 0 1 . , 330 -
$ (�j i \\ �, 3. —""'� "'`• a .-,-. r_. +_ten. -s_,_ �+'
4
SCHULTZ ENGINEERING LLC
TBPE NO. 12327
2730 Longmire, Suite A
College Station, Texas 77845
978.784.3900
SURVEYED DESIGNED DRAWN APPROVED JOB NO. DATE
JIM WALL JPS EL JPS 19-162 AUGUST 2011
TDI --.BROODS
INTERNA TIONAL CENTER
LOT 1, BLOCK I LABORATORY & OFFICE
.BUILDING
COLLEGE STATION, TX
PRE DE VEL OPA,
DRAINA GE AREz�li,
SCALE
VERTICAL
HORIZONTAL 18=50
PLOTTING SCALE: _.1:1
FILE NAME: 10-124
I
A
o
7
�I
q
i
P jpa
'v
5.
3 " L
o POST 32'
,
t i 1 j �� {i\{\ 3, ,• ' �' - '` 30" POST 0 1 . , 330 -
$ (�j i \\ �, 3. —""'� "'`• a .-,-. r_. +_ten. -s_,_ �+'
4
SCHULTZ ENGINEERING LLC
TBPE NO. 12327
2730 Longmire, Suite A
College Station, Texas 77845
978.784.3900
SURVEYED DESIGNED DRAWN APPROVED JOB NO. DATE
JIM WALL JPS EL JPS 19-162 AUGUST 2011
TDI --.BROODS
INTERNA TIONAL CENTER
LOT 1, BLOCK I LABORATORY & OFFICE
.BUILDING
COLLEGE STATION, TX
PRE DE VEL OPA,
DRAINA GE AREz�li,
SCALE
VERTICAL
HORIZONTAL 18=50
PLOTTING SCALE: _.1:1
FILE NAME: 10-124
FW461"11"Ll
Post -Development
Drainage Area Map
r
a�
/r
t':44.
\ /
50 25 0 50 � I I d , \ � \ \ . a � \ \ \ \ 38\ l / \\ \ '• ", ; � / /
SCALE IN FEET \ \ ?s \ \ \ \ \
v.r
D/A 201
........... _ . .92 ACRES 3�",Lo
III { III MM � � � I y I I I \ / � •— ______
/ 1111 1�
EXISTING
TI��TCr -
<<\ DETENTI
\\ \ OND 1 1
s� /
POND OUTLET \, / / // .l / / / l 1 j /
SIPHON PIPE \ / y / .• iti / 1
�
�
\ \ 1I
N04
/ow I �LWA
SCHULTZ ENGINEERING LLC
TRPE NO. 12327
2730 Longmire, Suite A
College Station, Texas 77845
979.764.3900
SURVEYED DESIGNED DRAWN APPROVED JOB NO. DATE
JIM WALL JPS EL JPS 11-189 JANUARY 2012
TDI --BROOKS
INTERNA TIONAL CENTER
LOT 1, BLOCK I LABORATORY & OFFICE
BUILDING
COLLEGE STATION, TX
-
AL
SCALE
VERTICAL
HORIZONTAL V1=50,
PLOTTING SCALE: 1:1
FILE NAME: 11-189
74-
/
EXHIBIT C
Detention Pond Design
0
I \ k-
\ `r3 329 \
\ as Q
N
10 , \Nv
Iq
40 20 0 _F40
SCALE IN FEET
' ^//v/ ///
®i
322.35
ly
NORMALPOOL
EXISTING
POND
7 /
POND OUTLET
\ \ \\\\ \\®® SIPHON PIPE
-._ - - - - \ \ 324:6
100 YR W.S.
M
O4ERFIOW SPILLWAY
M I
I /
i M I i I
I i i
\ 1 M 1 \ \
r l \ I \ \ \
SCHULTZ ENGINEERING LLC
TBPE N0. 12327
2730 Longmire, Suite A
College Station, Texas 77845
979.764.3900
SURVEYED DESIGNED DRAWN APPROVED JOB NO. DATE
JIM WALL, JPS EL JPS 11-162 AUGUST 2011
327
327
14'
325.35.
-TOP
D
325
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_
325
DETAIL
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323
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EEP
319
319
COL -LAR
317
317
1
3'
315
315
SL
PE=16.7%
313
313
-INLET
PIPE
/
312
311
311
MTN.
LE
GT
4'
310.75
SCALE: 1 "=2' VER.
1 "=10' HOR.
TDI -BROOKS INTERNATIONAL
POND OUTLET STRUCTURE
3" VENT PIPE-�\
W/ 3" VALVE
W.S. 32_2_35
6" STEEL
SHIELD PIPE
TDI -BROOKS
INTERNA TIONAL CENTER
LOT 1, BLOCK > LABORATORY & OFFICE
BUILDING
COLLEGE STA TION, TX
5
1
VENT DETAIL
N. T. S.
-15'
EL. 324.0
OND 0 VERFL 0 W SP.
N. T. S.
22.
USE SUPPRTS AS
NEEDED IT WELD 6"
SHIELD If E TO
8" PPE
WA Y D
mil
TAIL
L. 325.35
SCALE
VERTICAL
HORIZONTAL 1 "=40'
PLOTTING SCALE: 1:1
FILE NAME: 10-124
EXHIBIT
Drainage Report
for
TDIBrooks International — Office Building
South Dowling Road
Brazos County, Texas
December, 2011
Engineer:
SCHULTZ ENGINEERING LLC
TBPE Firm Registration No. 12327
P.O. Box 11995
College Station, TX 77842
2730 Longmire Drive
College Station, Texas 77845
(979)764-3900
Developer.
TDI/Brooks International
1902 Pinon
College Station, Texas 77842
(979)693-3446
Drainage Report
For
TDI/Brooks International - Office Building
ENGINEER
SCHULTZ ENGINEERING, LLC.
P.O. Box 11995
College Station, Texas 77842
Phone/Fax: (979)764-3900
OWNER
TDI/Brooks International, Inc.
1902 Pinon
College Station, Texas 77845
Phone: (979) 693-3446
GENERAL DESCRIPTION AND LOCATION
Location: This project is located on a 54 acre tract of land located at the north east
corner of the intersection of IG&N Road and South Dowling Road in
Brazos County.
Description.
• Area: 54 acres
• Proposed Land Use: Commercial — Laboratory and Office Facilities
• Existing Land Use: Vacant - Agricultural
• Land Description: Ground that slopes toward the southwest to IG&N Road.
Adjoining Land Use: The site is bounded on the west by rural residential properties, on the
south by IG&N Road and on the east by South Dowling Road.
Primary Drainage Facility: Tributary of Peach Creek
Flood Hazard Information:
FEMA FIRM: # 48041 CO200 C
Floodplain: No portion of this Phase lies within the floodplain of Peach Creek or its
tributaries.
HYDROLOGIC CHARACTERISTICS
This phase of the development of this property will be located on the southwest portion of the
property. This portion of the property drains to the existing detention/retention pond at the
southwest portion of the tract and then into the right-of-way of IG&N Road. The current
condition of the land is pasture with some scattered large trees.
GENERAL STORMWATER PLAN
The drainage plan for this development will involve the sheet flow of runoff collected into the
private drive ditches, parking lot and drive aisles for the laboratory and office building. The
runoff will then be discharged through curb cuts and culverts into swales and then into the
existing detention pond. One culvert is proposed to pass runoff under the sidewalks between the
buildings.
Page I of 3
COORDINATION & STORMWATER PERMITTING
The project will require that a NOI be filed and the TPDES General Permit TXR 150000
requirements be met as required by the Texas Commission for Environmental Quality. No other
permits are anticipated for this project.
DRAINAGE DESIGN
General Information: Stormwater runoff from the site will flow into the ditches along the
drives and the pavement areas, then into culverts which discharge into
swales. The flow into the parking area and drive aisles is discharged
from these areas through curb cuts. The flow then enters swales that
direct the runoff to the existing detention pond.
T, Methodology: TR 55
T, Minimum 10 minutes
Design Storm Event. 10-year —private storm sewer
100-year —private storm sewer
Pipe Materials: HDPE PIPE
Manning's n Value: 0.012
Runoff Coefficients: 0.35 Landscape Area, and 0.95 for Pavement Areas
Design Constraints: Max, water depth in the parking lot = 6 in. or 0.5 ft. for 100 year storm
event.
Min. flow velocity = 2.5 fps
Max. flow velocity = 15 fps
Design Software: Excel spreadsheets, DODSON HydraCalc Hydraulics, Civil 3D
Hydraflow
This software was used to compute curb opening capacity, flowrate and
velocity through each curb opening and culvert pipe. All of this
information is shown in the summary tables in Appendix A. The
software was also used to compute the depth of flow and velocity in the
swales.
Design Analysis: The Drainage Area Summary/Analysis in Appendix A has the runoff
calculations, curb opening size and depth at each opening. Appendix A
also includes the size of the culverts that the drainage areas with culverts
require. An evaluation of the proposed drainage swales was preformed
with the Laboratory Building Drainage Analysis.
Page 2 of 3
Design Results The data presented in the Appendices indicates the maximum water
depth in the parking lot is in accordance with the requirements of the
design guidelines. The private storm sewer culvert passed the 10 year
and 100 year storm event runoff without overtopping the drives.
Applicable Exhibits: Exhibit A — Drainage Area Map
Appendix A — Drainage Area Summary/Analysis
CERTIFICATION
I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report for
the drainage design for TDI Brooks International Corporate Headquarters Office Building, was
prepared by me in accordance with the provisions of the Unified Stormwater Design Guidelines.
,t
....... Joseph P. Schultz, P.E.
F-12327
SCHULTZ ENGINEERING, LLC.
Page 3 of 3
EXHIBIT A
Drainage Area Map
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LABORATORY BUILDING
SOUTH DOWLING ROAD, COLLEGE DRAINAGE AREA MAP
STATION, TX
APPENDIX A
Drainage Area Summary/Analysis
TDI-Brooks Corporate Headquarters Office Building
Appendix A
Proposed Storm Sewer Analysis
Drainage Area Summary/Analysis
Area #
Area, A
(acres)
C
tc
(min)
10 year storm
100 year storm
Curb Opening/
Pipe Size
Parking Lot Depth
Ito
(In/hr)
Ota
(cfs)
Itoo
(INhr)
Omo
(cfa)
(it)/
(in)
Yta
(In)
YIN
(in)
301
1.380
0.400
37.4
4.318
2.38
5.926
3.27
15,
302
0.72.0
0A00
26.6
5.298
1.53
7.225
2.08
15"
-
-
303
0.970
0.400
42.1
4.007
1.55
5.513
2.14
15.1
-
-
304
0.970
0.450
37.6
5,902
2.58
4-
3.48
4.30
305
0,220
0.950
10.0
0
11.639
2.43
15"
306
1.520
0.400
23.5
6
7.734
4.70
Ditch307
0.140
0.950
10.0
W4.30O1.88
5
11.639
1.55
2-
3.99
4.86
30B
0.080
0.950
10.0
6
11.639
0.88
2-
2.74
3.35
309
0860
0,500
10.0
1
11,639
5.00
16,310
0.100
0.950
10.0
2
11.639
1.11
Z
3.18
3.89
311
0.070
0.950
10.0
8.635
0.57
11.639
0.77
1'
3.99
4.86
312
0.490
0.350
10.0
8.636
1.48
11.639
2.00
Ditch
'SEE ATTACHED SKETCHES FOR HEADWATER CALCULATIONS AND CULVERT INFORMATION. ALL HEADWATER FOR THE 100 YEAR STORM EVENT
IS BELOW THE TOP OF THE ROAD.
CULVERT NO.1
10 year storm
100 year storm
Area, A
C
tc
Area #
Ito
Oto
Imo
Otoo
(acres)
(min)
(INhr)
(cfa)
(INhr)
(cfa)
302, 303, 304 & 309
3.520
0.450
42.1
4,007
6.35
5,513
1 8.73
The Rational. Method
Q = CIA
I = b / (tc+dr
tc = U(V"60)
O = Flow (cfs)
tc = Time of concentration (min)
L = Length (it
A = Area (acres)
V = Velocity (fllsec)
C = Runoff Coeff.
I = Rainfall Intensity (in/hr)
Brazos County.,
gear storm 100 year storm
b=80 b=96
d = 8.5 d = 8.0
e = 0.763 e = 0,730
Culvert Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc.
Thursday, Dec 15 2011
Culvert No. 1 - 10 Year Storm
Invert Elev Dn (ft)
= 327.00
Calculations
Pipe Length (ft)
= 30.00
Qmin (cfs)
= 6.35
Slope (%)
= 0.80
Qmax (cfs)
= 8.73
Invert Elev Up (ft)
= 327.24
Tailwater Elev (ft)
= (dc+D)/2
Rise (in)
= 18.0
Shape
= Cir
Highlighted
Span (in)
= 18.0
Qtotal (cfs)
= 6.35
No. Barrels
= 1
Qpipe (cfs)
= 6.35
n-Value
= 0.012
Qovertop (cfs)
= 0.00
Inlet Edge
= Projecting
Veloc Dn (ft/s)
= 4.07
Coeff. K,M,c,Y,k
= 0.0045, 2, 0.0317, 0.69, 0.5
Veloc Up (Il
= 5.18
HGL Dn (ft)
= 328.24
Embankment
HGL Up (ft)
= 328.22
Top Elevation (ft)
= 330.00
Hw Elev (ft)
= 328.70
Top Width (ft)
= 4.00
Hw/D (ft)
= 0.97
Crest Width (ft)
= 4.00
Flow Regime
= Inlet Control
Culvert Report
Hydraflow Express Extension for AUtoCAD® Civil 3D® 2012 by Autodesk, Inc.
Culvert No. 1 -100 Year Storm
Invert Elev Dn (ft)
= 327.00
Calculations
Pipe Length (ft)
= 30.00
Qmin (cfs)
Slope (%)
= 0.80
Qmax (cfs)
Invert Elev Up (ft)
= 327.24
Tailwater Elev (ft)
Rise (in)
= 18.0
Shape
= Cir
Highlighted
Span (in)
= 18.0
Qtotal (Cfs)
No. Barrels
= 1
Qpipe (cfs)
n-Value
= 0.012
Qovertop (cfs)
Inlet Edge
= Projecting
Veloc Dn (ft/s)
Coeff. K,M,c,Y,k
= 0.0045, 2, 0.0317, 0.69, 0.5
Veloc Up (ft/s)
HGL Dn (ft)
Embankment
HGL Up (ft)
Top Elevation (ft)
= 330.00
Hw Elev (ft)
Top Width (ft)
= 4.00
Hw/D (ft)
Crest Width (ft)
= 4.00
Flow Regime
Thursday, Dec 15 2011
= 6.35
= 8.73
= (dc+D)/2
= 8.73
= 8.73
= 0.00
= 5.29
= 6.00
= 328.32
= 328.39
= 329.06
= 1.21
= Inlet Control
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