HomeMy WebLinkAbout27 DP Gateway Retail Center 04-05 730 Earl Rudder FWY SDrainage Report, Water and Sewer Demand Analysis, Load Analysis
For
Gateway Retail Center
College Station, Texas
March 2004
Revised March 24, 2004
Developer:
Todd Carnes
College Station, Texas
(979) 693-7835
Prepared By:
Rhodes Architectural Industries
P.O. Box 9389
College Station, Texas 77842
(979) 764-7150
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q :20~
3 -c91...J -03
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Drainage Report
for
Gateway Retail Center
College Station, Texas
February 2004
Revised March 2004
Developer:
Todd Carnes
College Station, Texas
(979) 693-7835
Prepared By:
TEXCON General Contractors
1707 Graham Road
College Station, Texas 77845
(979) 764-7743
CERTIFICATION
I, Joseph P . Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report
for the drainage design for the Gateway Retail Center in College Station, Texas, was prepared by me in
accordance with the provisions of the City of College Station Drainage Policy and Design Standards
for the owners hereof, with the exception that storm water runoff detention is not being required at this
site since the site discharges directly into a storm sewer system which discharges into the existing
detention facility for the entire Gateway Development.
TABLE OF CONTENTS
GATEWAY RETAIL CENTER
CERTIFICATION ................................................................................................................................................................... 1
TABLE OF CONTENTS ........................................................................................................................................................ 2
LIST OF TABLES .................................................................................................................................................................. 2
INTRODUCTION ............................................................................................................................................................•...... 3
GENERAL LOCATION AND DESCRIPTION .................................................................................................................. 3
DEVELOPMENT DRAINAGE PATTERNS ....................................................................................................................... 3
DRAINAGE DESIGN CRITERIA ........................................................................................................................................ 3
. STORM WATER RUNOFF DETERMINATION ............................................................................................................... 4
STORM SEWER PIPE & INLET DESIGN ..................................................•...................................................................... 4
DETENTION FACILITY ...................................................................................................................................................... 5
CONCLUSIONS ..................................................................................................................................................................... 5
APPENDIX A .......................................................................................................................................................................... 6
Calculations
EXHIBIT ..........................................................................................................•.................................................................... 11
Sheet S3 -Drainage and Grading Plan
LIST OF TABLES
TABLE 1-Rainfall Intensity &.RunoffData ..................................................................................................................... .4
TABLE 2 -Runoff Data ......................................................................................................................................................... 4
2
DRAINAGE REPORT
GATEWAY RETAIL CENTER
INTRODUCTION
The purpose of this report is to provide the hydrological effects of the construction of th e
infrastructure for the Gateway Retail Center project, and to show that the storm w ater runoff
will be controlled in such a manner so as to have minimal offsite or downstream impact.
GENERAL LOCATION AND DESCRIPTION
The project is located on approximately 1.5 acres located in the Gateway Development in
College Station, Texas. The site is a portion of Block 1, Lot 2R of the Phase 1 of the Gateway
Subdivision . The project will be developed in 2 phases with approximately 0 .8 acres being
developed in Phase 1. This site has previously been developed with the clearing and grading
completed with the Home Depot project. In addition, the site has previously constructed
driveways on all four sides , some of which are on this tract. The site falls appro x imately 6' in
elevation from the west side to east side of the site .
DEVELOPMENT DRAINAGE PATTERNS
The storm water runoff from the site flows into an existing storm sewer inlet at the north comer
of the site. The post development drainage area boundary for both phases is shown on Sheet
S3, the Drainage and Grading Plan. The grading plan is based on elevations re lati ve to the site
with the existing grate inlet top assum ed to be Elevation 95.3, as shown on the plans . This inlet
is located near the existing driveway east of the site . The existing storm sewer inl et was
constructed with the Home Depot development located to the north of this site. The
Drainage/Detention Report for the Home Depot development was prepared in August 2002 by
Bury+ Partners -SA, Inc. A review of this report shows that this site is part of Drainage Area
7, which had an area of 2 .5 acres, a "c" value of 0.85, and a time of concentration, Tc , va lue of
10 minutes. This area included a portion of Lot 2R to the east of this site, which is being
developed separately and will have its own storm sewer system.
DRAINAGE DESIGN CRITERIA
The design parameters for the storm sewer are as follows :
• The Rational Method is utilized to determine peak storm water runoff rates for the
storm sewer design .
• Desi gn Storm Frequency
Storm sewer system
• Runoff Coefficients
10 and 100 -year storms eve nt s
Landscap e ar eas C = 0. 60
Imperv ious sur faces C = 0.90
• Rainfall Intensity equation s a nd valu e s for Braz o s Count y can be found in Ta bl e I .
• Tim e of Con centration , tc -Fo r s ma ll er drain age a re a s, a minimum tc of I O minut es is
use d to de te rmin e th e ra in fa ll int e nsit y valu es.
,
'
TABLE 1 -·R ai n fa ll Intensity & R u noff Data
Rai nfall Intensity Va l ues
(in/hr)
Storm tc =
Event 10 min
Is 7 .693
110 8 .635
'2s 9 .861
lso 11-148
1100 11 .639
Brazos
County:
51:'.ear storm 10 l:'.ear storm
b = 76 b= 80
d= 8 .5 d= 8 .5
e= 0.785 e= 0 .763
I = b I (tc+d)e
I = Rainfall Intensity (in/hr)
tc = U(V*60)
tc = Time of concentration (min)
L = Length (ft)
V = Velocity (ft/sec)
25 l:'.ear storm 50 l:'.ear storm 100 l:'.ear storm
b= 89 b= 98 b= 96
d = 8.5 d = 8.5 d= 8.0
e = 0.754 e= 0-745 e= 0 .730
(Data taken from State Department of Highwal:'.s and Public Transportation Hl:'.draulic Manual, page 2-16)
STORM WATER RUNOFF DETERMINATION
The peak runoff values were determined in accordance with the criteria presented in the
previous section for the I 0-and I 00-year storm ev ents. The runoff coefficients are based
on the development of both phases o f this site . The drainage ar ea is shown on Sheet S3 ,
The Drainage and Grading Plan. Runoff conditions are summarized in Table 2.
TABLE 2 -Runoff Data
Area No. Area S iz e Co m posit e 110 010 1100 0100
(acres) c (in/h r ) (cfs) (i n /h r ) (cfs)
1 . 1 .18 0 .85 8 .64 8 .67 11.64 11.67
STORM SEWER PIPE & INLET DESIGN
The existing private storm _sewer will collect the runoff from both phases of this project. A
small portion of the project site will drain directly into the existing driveway along the
northern boundary of the site . This runoff will eve ntually enter the public storm sewer
system through the existing inlets located in the existing driveways .
The grate for the existing storm sewer inlet is a 36" x 36 " V-57 36 grate manu fa ctured by
Ea st Jordan Iron Works . Th e op en area fo r th e gra te is 6 93 square inch es, or 4.8 1 squ are
fee t (sf). Assuming the grate is 50 % c lo gge d, th e ava ilabl e o pen area is 2.4 sf.
T he d epth of water abo ve th e gra te is d ete rmin ed by th e o rifi ce equati o n:
Q = 4 .82* A g * y 112
4
Therefore, for the 10-and 100-year storm events the following depths are calculated:
Q1o = 8.67 cfs ~ y = 0 .56' = 6.74"
Q1 00 = 11.67 cfs ~ y = 1.02' = 12 .2"
The top of the grate is proposed to be at elevation 95.3, and the top of the berm around the
inlet will be constructed to elevation 97.0. There will be 8" of freeboard during the 100-
year storm event.
The existing 30" diameter storm sewer pipe can adequately carry the runoff. The velocity
in this pipe will be 6 .3 fps and 6.8 fps for the 10-year and 100-year storm events ,
respectively.
DETENTION FACILITY
No storm water detention is required for this site because the existing private and public
storm sewer systems and the Home Depot detention pond were designed for the full
development of the entire Gateway Subdivision development. The design of the facilities
is provided in the aforementioned Drainage/Detention Report prepared by Bury + Partners .
CONCLUSIONS
The construction of this project will increase the storm water runoff from this site.
However, the runoff will be carried through the proposed and existing storm sewer system
and into the existing detention pond. No flood damage to downstream or adjacent
landowners is expected as a result of this development.
5
APPENDIX A
Calculations
(J
10 -year.txt
Manning Pipe calculator
Given Input Data:
shape .......................... .
solving for .................... .
Diameter ....................... .
Flowrate ....................... .
slope .......................... .
Manning's n .................... .
computed Results :
Depth .......................... .
Area ........................... .
wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
circular
Depth of Flow
30.0000 in
8.6700 cfs
0.0100 ft/ft
0.0140
9.7322 in
4.9087 ft2
1. 3799 ft2
36.3587 in
94.2478 in
6. 2831 fps
5.4652 in
32.4406 %
38.0873 ·cfs
7.7591 fps
Pa g e 1
. . .
100 -year.t xt
Manning Pipe calcul a tor
Given Input Data:
shape .......................... .
solving for .................... .
Diameter ....................... .
Fl owrate ....................... .
s l ope .......................... .
Manning's n .................... .
computed Results:
Depth .......................... .
Area ........................... .
wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
velocity ........................ .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
circular
Depth of Flow
30.0000 in
11.6700 cfs
0 .0100 ft/ft
0 .0140
11. 3955 in
4.9087 ft2
1. 7107 ft2
39.8436 in
94.2478 in
6.8217 fps
6.1828 in
37.9850 %
38.0873 .cfs
7.7591 fps
Page 1
EXHIBIT
Sheet 83 -Drainage and Grading Plan
11
I ,/
Gateway Retail Center
Water Demand Analysis
Irrigation -25 gpm -1" water meter
Carnes Design Center
Lavatory
Shower
Water Closet
Urinal
Service Sink
Quantity
2
2
3
2
Fixture Unit 1
2 .0
4 .0
5.0
5 .0
3.0
38 Fixture Units -Demand= 25.7 gpm 2 -3/4" Water Meter
2 Rental Spaces
Item ~ Fixture Unit 1
Lavatory 2 2 .0
Dishwasher 2 1.4
Water Closet 3 5 .0
Urinal 2 5 .0
Kitchen Sink 2 4 .0
Total
Fixture Unit
4 .0
8.0
15 .0
5 .0
6 .0
38.0
Total
Fixture Unit
4 .0
2 .8
15.0
10.0
8.0
39.8
39 .8 Fixture Units -Demand = 26 .3 gpm 2 -3/4" Water Meter for each Space
Total Water Demand
Irrigation
Carnes Design Center
Rental Spaces
Quantity
QQ!!l
25 .0
25 .7
2@26.3
103.3 gpm = 0.23 cfs
2" Waterline @ 0.23 cfs
Headloss - 1 psi Velocity= 10 .5 fps
2" diameter Waterline is adequate for this development
Sewer Demand Analysis
Sewer Demand -90% of Water Use (exduding irrigation)
78.3 gpm x 0 .9 = 70.5 gpm -Peak Flow
Average Daily Flow -25380 gpd
1. Table E1 0 1B • 2000 Intern ational Plumbing Code
2. Table E1 02 • 2000 Intern ational Plu mb in g Code
. :
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APPENDIX E
.,
!, .
TA BLE E1018
LOAD VALUES ASSIGNED TO FIXTURES 8
LOAD VALUES, IN WATER SUPPLY FIXTURE UNITS ( ' '• TYPE OF SUPPLY
FIXTURE OCCUPANCY CONTROL Cold Hot Total
Bathroom group Private Flush tank 2.7 1.5 3.6 ' Bathroom group Private Flush valve 6 .0 3 .0 8.0
Bathtub Private Faucet 1.0 1.0 1.4 -·
Bathtub Public Faucet 3 .0 3 .0 4 .0 7-f.
Bidet Private Faucet 1.5 1.5 2.0
. !:t
:.~
Combination fixture Private Faucet 2 .25 2.25 3 .0 ' Dishwashing machin e Private Automatic .-1.4 1.4 '
Drinking fountain Offices , etc. 3/g" valve 0 .25 -0 .25
Kitchen sink Private Faucet 1.0 1.0 1.4
Kitchen sink Hotel, restaurant Faucet 3.0 3 .0 4.0
Laundry trays (1 to 3) Private Faucet 1.0 1.0 1.4
Lavatory Private Faucet 0.5 0 .5 0 .7
Lavatory Public Faucet 1.5 1.5 2.0
Service sink Offices, etc. Faucet 2.25 2 .25 3.0
Shower head Public Mixing valve 3.0 3 .0 4.0
Shower head Private Mixing valve 1.0 1.0 1.4
Urinal Public l" flush valve 10.0 -10.0
Urinal Public 3/4" flush valve 5 .0 -5.0
Urinal Public Flush tank 3.0 -3.0
Washing machine (8 lbs .) Private Automatic LO 1.0 1.4
Washing machine (8 lbs .) Public Automatic 2.25 2.25 3 .0
Washing machine (15 lbs .) Public Automatic 3 .0 3 .0 4.0
Water closet Private Flush valve 6.0 -6.0
Water closet Private Flush tank 2 .2 -2.2
Water closet Public Flush valve 10.0 -10.0
Water closet Public Flush tank 5.0 -5 .0
Water closet Public or private Flushometer tank 2.0 -2.0
For SI: l inch = 25.4 mm , l pound = 0.454 kg.
a . For fix tures not li s ted, loads should be assumed by comparing the fixture to one listed using waterin similar quantities and at similar rates . The assigned loads for
fixtures with both hot and cold water supplies arc given for separate hot and cold water loads and for total load, the separate hot and cold water loads being thrcc-
fourths of the total load for the fixture in each case.
116 2000 INTERNATIONAL PLUMBING CODE®
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APPENDIX E
TABLE E102
TABLE FOR ESTIMATING DEMAND
SUPPLY SYSTEMS PREDOMINANTLY FOR FLUSH TANKS SUPPLY SYSTEMS PREDOMINANTLY FOR FLUSH VALVES
Load Demand Load Demand
(Water supply (Water supply
fixture units) (Gallons per minute) (Cubic feet per minute) fixture units) (Gallons per minute) (Cubic feet per minute)
l 3.0 0.40104 ---
2 5.0 0 .6684 ---I
3 6.5 0 .86892 ---
4 8.0 l .06944 ---
5 9.4 1.256592 5 15 .0 2.0052
6 10.7 l.430376 6 17.4 2.326032
7 11.8 l.577424 7 19 .8 2.646364
8 12.8 l.711104 8 22 .2 2.967696
9 13 .7 l.831416 9 24 .6 3.288528
10 14.6 l.951728 10 27.0 3.60936
11 15.4 2.058672 11 27.8 3.716304
12 16 .0 2.13888 12 28 .6 3.823248
13 16.5 2.20572 13 29.4 3.930192
14 17 .0 2.27256 14 30 .2 4.037136
15 17 .5 2.3394 15 31.0 4.14408
16 18 .0 2.90624 16 31.8 4 .241024
17 18 .4 2.459712 17 32.6 4.357968
18 18 .8 2.513184 18 33.4 4.464912
19 19.2 2.566656 19 34 .2 4.571856
20 19 .6 2.620128 20 35 .0 4.6788
25 21.5 2.87412 25 38 .0 5.07984
30 23 .3 3.114744 30 42 .0 5.61356
35 24 .9' 3.328632 35 44 .0 5.88192
40 26,3 I 3.515784 40 46.0 6.14928
45 27 .7 3.702936 45 48.0 6.41664
50 29.l 3.890088 50 50.0 6.684
60 32.0 4 .27776 60 54.0 7.21872
70 35 .0 4.6788 70 58 .0 7.75344
80 38 .0 5.07984 80 61.2 8.181216
90 41.0 5.48088 90 64.3 8.595624
100 43.5 5.81508 100 67 .5 9.0234
120 48 .0 6.41664 120 73.0 9.75864
140 52.5 7.0182 140 77.0 10.29336
160 57 .0 7.61976 160 81.0 10.82808
180 61.0 8.15448 180 85.5 11.42964
200 65 .0 -8.6892 200 90.0 12.0312
225 70.0 9.3576 225 95.5 12.76644
250 75 .0 10.0260 250 101.0 13.50168
275 80.0 10.6944 275 104.5 13 .96956
300 85 .0 11 .3628 300 108 .0 14.43744
400 105 .0 14.0364 400 127 .0 16 .97736
500 124.0 16.57632 500 143 .0 19 .11624
750 170 .0 22 .7256 750 177.0 23.66136
1,000 208 .0 27 .80544 1,000 208 .0 27.80544
1,250 239 .0 31.94952 1,250 239 .0 31.94952
1,500 269 .0 35 .95992 1,500 269 .0 35 .95992
1,750 297 .0 39 .70296 1,750 297 .0 39 .70 296
(Co11tinu e d )
2000 INTERNATIONAL PLUMBING CODE® 117
.. , '
2 11 Waterline -Gateway Center
Hazen-Williams Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Length ......................... .
Coefficient .................... .
Computed Results:
Headless ....................... .
Area ........................... .
Perimeter ...................... .
Velocity ....................... .
Circular
Headloss
2.0000 in
0.2300 cfs
10.0000 ft
150.0000
1.7894 ft
0.0218 ft2
6.2832 in
10.5424 fps
Attn. John LOAD AN:J\'CYSIS
GATEWAY RETAIL CENTER
Gas Water Heater and Heating-System
120/208 Volt 3 Phase
CENTER SPACE Builders Showroom 3;556 Square F~t
CATEGORY
Lighting
General Receptacles l20v
Lighting Display Pigs 120v
(on ceiling)
Motors-Exhaust Fans 120v
{incl 1.25%)
CONNECTED LOAD
8303w
6660w
8100w
4'800w
DETAIL
-8 Recessed X 120w= %0w
12 2X4FlourX l04w==l248w
6 Flour Strip X 55w= 330w
3 Exits X SSw= l6.5w
56 Gen Incaod X 100w=5600w
Total =8303w
3 7 X UOw = 6660w
27 X 300w... 8100w
3 x r600 = 41UO"w
Kit-Display Oven Pigs 208v 2polc HJOOOw
#1 Heating {fan only) 120v
#2 Heating (fan only.) f20v
# 1 Cooling 208v 3 phase
#2 Cooling 208v 3 phase
HOUSE PANEL
1630w
loSOW
ttZSOw
11250w
l x 1680w = 1680w
I X 16BOw • 1:6BOw
l X fl!S-Ow=ITT50w
[ (25 running amps) X 1.25 %]
1 X ll 250w= 11 ZSOw
[ (25 running amps) X I.2S-%}
Total 6372Jw =177 Amps {I7.92w per Sq Ft)
Total 8558w = 23 Amps
3-400w MH/47'W ea= 1434w
6-lSOw MH/104wea= 6I4w
20-lOOw Incud: IOOwu=-2UOUW
3-WP GF1 Pigs lSOOw ea= 4500w
ONE SP ACE EACH SIDE 1977 Sq Ft each Empty Space-Not Yet Leased =Total 3954 Sq Ft
Tofaf 708S5w =197 Amp$ Estiinateafoaa(&aseaon cemenpaceJ
l 7.92w per Sq Ft= 708S5w
UIEltt(dc
2SS M11rlno Rd
PhOIK (fZ,> 778-JJ.f4)
Total 143136w=398 Amps Conntcfed"Lolftf No Demand racfbr
Drainage Report, Water and Sewer Demand Analysis, Load Analysis
For
Gateway Retail Center
College Station, Texas
March 2004
Revised March 24, 2004
Developer:
Todd Carnes
College Station, Texas
(979) 693-7835
Prepared By:
Rhodes Architectural Industries
P.O. Box 9389
College Station, Texas 77842
(979) 764-7150
OL/-:J ~
q :20~
3 -eiLl .. o~
~
t " .....
Drainage Report
for
Gateway Retail Center
College Station, Texas
February 2004
Revised March 2004
Developer:
Todd Carnes
College Station, Texas
(979) 693-7835
Prepared By:
TEXCON General .Contractors
1707 Graham Road
College Station, Texas 77845
(979) 764-7743
CERTIFICATION
I, Joseph P. Schultz, Licensed Professional Engineer No . 65889, State of Texas , certify that this report
for the drainage design for the Gateway Retail Center in College Station, Texas, was prepared by me in
accordance with the provisions of the City of College Station Drainage Policy and Design Standards
for the owners hereof, with the exception that storm water runoff detention is not being required at this
site since the site discharges directly into a storm sewer system which discharges into the existing
detention facility for the entire Gateway Development.
TABLE OF CONTENTS
GATEWAY RETAIL CENTER
CERTIFICATION ............................................................................................................................................................•...... 1
TABLE OF CONTENTS ........................................................................................................................................................ 2
LIST OF TABLES .................................................................................................................................................................. 2
INTRODUCTION ................................................................................................................................................................... 3
GENERAL LOCATION AND DESCRIPTION .................................................................................................................. 3
DEVELOPMENT DRAINAGE PATTERNS ....................................................................................................................... 3
DRAINAGE DESIGN CRITERIA ........................................................................................................................................ 3
. STORM WATER RUNOFF DETERMINATION ............................................................................................................... 4
STORM SEWER PIPE & INLET DESIGN ......................................................................................................................... 4
DETENTION FACILITY ...............................................................................•...................................................................... 5
CONCLUSIONS ..................................................................................................................................................................... 5
APPENDIX A ...................................................................................................•...................................................................... 6
Calculations
EXHIBIT ............................................................................................................................................................................... 11
Sheet SJ -Drainage and Grading Plan
LIST OF TABLES
TABLE 1 -Rainfall Intensity & Runoff Data ..................................................................................................................... .4
TABLE 2 -Runoff Data ........................................................................................................................................................ .4
DRAINAGE REPORT
GATEWAY RETAIL CENTER
INTRODUCTION
The purpose of this report is to provide the hydrological effects of the construction of the
infrastructure for the Gateway Retail Center project, and to show that the storm water runo ff
will be controlled in such a manner so as to have minimal offsite or do w nstrea m impact.
GENERAL LOCATION AND DESCRIPTION
The project is located on approximately 1.5 acres located in the Gateway Development in
College Station, Texas . The site is a portion of Block 1, Lot 2R of the Phase 1 of the Gateway
Subdivision. The project will be developed in 2 phases with approximately 0.8 acres being
developed in Phase 1. This site has previously been developed with the clearing and grading
completed with the Home Depot project. In addition, the site has previously constructed
driveways on all four sides, some of which are on this tract. The site falls approximately 6' in
elevation from the west side to east side of the site .
DEVELOPMENT DRAINAGE PATTERNS
The storm water runoff from the site flows into an existing storm sewer inlet at the north comer
of the site . The post development drainage area boundary for both phases is shown on Sheet
S3 , the Drainage and Grading Plan. The grading plan is based on elevations relative to the site
with the existing grate inl et top assum ed to be Elevation 95.3, as shown on th e plans. Thi s inlet
is located near the existing driveway east of the site . The existing storm sewer inlet was
constructed with the Home Depot development located to the north of this site. The
Drainage/Detention Report for the Home Depot development was prepared in August 2002 by
Bury+ Partners -SA, Inc . A review of this report shows that this site is part of Drainage Area
7, which had an area of2.5 acres, a "c" value of 0 .85, and a time of concentration, Tc, value of
10 minutes. This area included a portion of Lot 2R to the east of this site, which is being
developed separately and will have its own storm sewer system.
DRAINAGE DESIGN CRITERIA
The design parameters for the storm sewer are as follows:
• The Rational Method is utilized to determine peak storm water runoff rates for the
storm sewer design .
• Desi gn Storm Frequency
Storm sewer system
• Runo ff Coeffici e nt s
10 and 100-year storms eve nts
Lands ca pe ar eas C = 0 . 60
Imp erv ious s ur faces C = 0 .90
• Rain fa ll Int ensit y equ ati o ns a nd va lu es for B raz o s Count y c an be fo und in Ta bl e I .
• Tim e of Co nce ntration , t, -Fo r s ma ll e r drain age a rea s, a minimum tc of I 0 minut es is
use d to d e te rmin e th ~ rain fa ll int e nsit y va lu es.
,
'
TABLE 1--Rainfall Intensity & Runoff Data
Rainfall Intensity Values
(in/hr)
Storm le=
Event 10 min
Is 7 .693
110 8.635
'2s 9.861
lso 11 .148
1100 11 .639
Brazos
County:
5 Y..ear storm 1 O Y..ear storm
b= 76 b= 80
d= 8.5 d= 8.5
e= 0.785 e= 0.763
I = b I (tc+d)0
I = Rainfall Intensity (in/hr)
tc = U(V*60)
tc = Time of concentration (min)
L = Length (ft)
V = Velocity (ft/sec)
25 Y..ear storm 50 Y..ear storm 100 'l..ear storm
b= 89 b= 98 b= 96
d= 8 .5 d= 8 .5 d= 8.0
e= 0.754 e= 0.745 e= 0 .730
(Data taken from State Department of HiqhwaY..S and Public Transportation HY..draulic Manual, page 2-16)
STORM WATER RUNOFF DETERMINATION
The peak runoff values were determined in accordance with the criteria presented in the
previous section for the 10-and 100-year storm events . The runoff coefficients are based
on the development of both phases of this site. The drainage area is shown on Sheet S3 ,
The Drainage and Grading Plan. Runoff conditions are summarized in Table 2 .
TABLE 2 -Runoff Data
Area No. Area Size Composite 110 010 1100 0100
(acres) c (in/hr) (cfs) (in/hr) (cfs)
1 . 1 .18 0.85 8 .64 8.67 11.64 11 .67
STORM SEWER PIPE & INLET DESIGN
The existing private storm ~sewer will collect the runoff from both phases of this project. A
small portion of the project site will drain directly into the existing driveway along the
northern boundary of the site. This runoff will eventually enter the public storm sewer
system through the existing inlets located in the existing driveways .
The grate for the existing storm sewer inlet is a 36" x 36" V-5736 grate manu fa ctured by
East Jordan Iron Works . The open area for th e grate is 693 square inches , or 4.81 squ are
fee t (sf). Assuming the grate is 50 % clo gge d, th e ava ilabl e op en area is 2.4 sf.
Th e depth o f w ater abo ve the grat e is dete rmin ed by th e orifi ce equ ati o n:
Q = 4.8 2* Ag * y 112
4
Therefore, for the 10 -and 100-year storm events the following depths are calcul ated:
Q1o = 8.67 cfs ~ y = 0.56 ' = 6.74"
Q1 00 = 11.67 cfs ~ y = 1.02' = 12.2 "
The top of the grate is proposed to be at elevation 95.3, and the top of the berm around the
inlet will be constructed to elevation 97.0 . There will be 8" of freeboard during the l 00 -
year storm event.
The existing 30" diameter storm sewer pipe can adequately carry the runoff. The velocity
in this pipe will be 6 .3 fps and 6 .8 fps for the 10-year and 100-year storm events ,
respectively.
DETENTION FACILITY
No storm water detention is required for this site because the existing private and public
storm sewer systems and the Home Depot detention pond were designed for the full
development of the entire Gateway Subdivision development. The design of the facilities
is provided in the aforementioned Drainage/Detention Report prepared by Bury + Partners .
CONCLUSIONS
The construction of this project will increase the storm water runoff from this site.
However, the runoff will be carried through the proposed and existing storm sewer system
and into the existing detention pond. No flood damage to downstream or adjacent
landowners is expected as a result of this development.
5
APPENDIX A
Calculations
10 -year.txt
Manning Pipe calculator
Given Input Data:
shape .......................... .
solving for .................... .
Diameter ....................... .
Flowrate ....................... .
slope .......................... .
Manning's n .................... .
computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
wetted Perimeter ............... .
Perimeter ...................... .
velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
circular
Depth of Flow
30.0000 in
8.6700 cfs
0.0100 ft/ft
0.0140
9.7322 in
4.9087 ft2
1.3799 ft2
36.3587 in
94.2478 in
6.2831 fps
5.4652 in
32.4406 %
38.0873 ·cfs
7.7591 fps
Pa g e 1
..
100 -year.txt
Manning Pipe calculator
Given Input Data:
shape .......................... .
solving for .................... .
Diameter ....................... .
Flowrate ....................... .
slope .......................... .
Manning' s n .................... .
computed Results:
Depth .......................... .
Area ........................... .
wetted Area .................... .
wetted Perimeter ............... .
Perimeter ...................... .
velocity ....... •.• .............. .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
circular
Depth of Flow
30.0000 in
11.6700 cfs
0.0100 ft/ft
0.0140
11.3955 in
4.9087 ft2
1.7107 ft2
39.8436 in
94.2478 in
6.8217 fps
6.1828 in
37.9850 %
38.0873 'cfs
7.7591 fps
Page 1
EXHIBIT
Sheet 83 -Drainage and Grading Plan
11
Gateway Retail Center
Water Demand Analysis
irrigation -25 gpm -1" water meter
Carnes Design Center
Lavatory
Shower
Water Closet
Urinal
Service Sin k
Quantity
2
2
3
1
2
Fixture Unit 1
2.0
4 .0
5 .0
5 .0
3 .0
38 Fixture Un its -Demand = 25 .7 gpm 2 -314 " Water Meter
2 Re ntal Spaces
Item Quantity Fixture Unit 1
Lavatory 2 2 .0
Dishwasher 2 1.4
Water Closet 3 5.0
Urinal 2 5.0
Kitchen Sink 2 4 .0
Total
Fixture Unit
4 .0
8.0
15 .0
5.0
6.0
38.0
Total
Fixture Un it
4 .0
2.8
15 .0
10 .0
8.0
39.8
39 .8 Fixture Units -Demand = 26 .3 gpm 2 -314" Water Meter for each Space
Total Water Demand
Irrigation
Carnes Des ign Center
Rental Spaces
Quantity
9.P!!l
25.0
25 .7
2@26 .3
103.3 gpm = 0.23 cfs
2" Waterline @ 0 .23 cfs
Headless - 1 psi Velocity= 10 .5 fps
2" diamete r Waterline is adequate for th is development
Sewer Demand Analysis
Sewer Demand -90% of Water Use (excluding irrigation)
78 .3 gpm x 0 .9 = 70 .5 gpm -Peak Flow
Average Dai ly Flow -25380 gpd
1. Table E1 01B -2000 Intern ational Plumbing Code
2 . Table E 102 -2000 International Plumbing Code
: '."i
• i-1
! • ~
·wan 'J' .-! ';I
·~ ::. ·1
f I
. l
I'
I
1,
APPENDIX E
TABLE E1018
LOAD VALUES ASSIGNED TO FIXTURES 8
TYPE OF SUPPLY LOAD VA LUES, IN WATER SUPPLY FIXTURE UNITS(~
FIXTURE OCCUPANCY CONTROL Cold Hot Total .,
Bathroom group Private Flush tank 2 .7 1.5 3 .6 =11 Bathroom group Private Flush valve 6 .0 3 .0 8 .0
Bathtub Private Faucet 1.0 1.0 1.4 ·~
Bathtub Public Faucet 3 .0 3 .0 4.0 ~
1.5
~
Bidet Private Faucet 1.5 2.0 1:
Combination fixture Private Faucet 2.25 2 .25 3 .0 -
Dishwashing machine Private Automatic .. -1.4 1.4 · -
--Drinking fountain Offices, etc. 3/g" valve 0.25 0.25 ~ Kitchen sink Private Faucet 1.0 1.0 1.4 ~ Kitchen sink Hotel, restaurant Faucet 3 .0 3 .0 4.0 I Laundry trays (1 to 3) Private Faucet 1.0 1.0 1.4 .. _
Lavatory Private Faucet 0 .5 0.5 0 .7
Lavatory Public Faucet 1.5 1.5 2.0
Service sink Offices, etc. Faucet 2.25 2 .25 3 .0
Shower head Public Mixing valve 3.0 3 .0 4.0
Shower head Private Mixing valve 1.0 1.0 1.4
Urinal Public l" flush valve 10.0 -10.0
Urinal Public 3/4" flus h valve 5.0 -5.0
Urinal Public Flush tank 3.0 -3.0
Washing machine (8 lbs .) Private Automatic 1.0 1.0 1.4
Washing machine (8 lbs.) Public Automatic 2 .25 2 .25 3 .0
Washing machine (15 lbs .) Public Automatic 3 .0 3 .0 4.0
Water closet Private Flush valve 6 .0 -6.0
Water closet Private Flush tank 2 .2 -2 .2
Water closet Public Flush valve 10.0 -10.0
Water closet Public Flush tank 5 .0 -5.0
Water closet Public or private Aushometer tank 2 .0 -2 .0
For SI : I inch = 25.4 mm, I pound = 0 .454 kg .
a. For fixtures not listed, loads should be assumed by comparing the fixture to one listed using water in similar quantities and at similar rates . The assigned loads for
fixtures with both hot and cold water supplies are given for separate hot and cold waterloads and for total load, the separate hot and cold waterloads being three -
fourths of the total load for the fixture in each case .
116 2000 INTERNATIONAL PLUMBING CODE®
~ .. ..
..
t
h
• '
f
t
i.
APPENDIX E
TABLE E102
TABLE FOR ESTIMATING DEMAND
SUPPLY SYSTEMS PREDOMINANTLY FOR FLUSH TANKS SUPPLY SYSTEMS PREDOMINANTLY FOR FLUSH VALVES
Load Demand Load Demand
(Water supply (Water supply
fixture units) (Gallons per minute) (Cubic feet per minute) fixture units) (Gallons per minute) (Cubic feet per minute)
1 3 .0 0.40104 ---
2 5 .0 0 .6684 ---I
3 6 .5 0 .86892 ---
4 8 .0 1.06944 ---
5 9.4 1.256592 5 15 .0 2.0052
6 10.7 1.430376 6 17.4 2.326032
7 11.8 1.577424 7 19 .8 2.646364
8 12 .8 1.711104 8 22 .2 2.967696
9 13.7 1.831416 9 24.6 3 .288528
10 14.6 1.951728 10 27.0 3 .60936
11 15.4 2.058672 II 27.8 3.716304
12 16.0 2.13888 12 28 .6 3.823248
13 16.5 2.20572 13 29.4 3.930192
14 17 .0 2.27256 14 30.2 4 .037136
15 17.5 2.3394 15 31.0 4.14408
16 18.0 2.90624 16 31.8 4.241024
17 18.4 2.459712 17 32.6 4.357968
18 18 .8 2.513184 18 33.4 4.464912
19 19 .2 2.566656 19 34.2 4.571856
20 19 .6 2.620128 20 35 .0 4.6788
25 21.5 2.87412 25 38.0 5.07984
30 23 .3 3 .114744 30 42.0 5 .61356
35 24.9' 3.328632 35 44.0 5.88192
40 26) I 3.515784 40 46 .0 6.14928
45 27 .7 3.702936 45 48.0 6.41664
50 29.1 3.890088 50 50.0 6 .684
60 32.0 4.27776 60 54.0 7 .21872
70 35 .0 4.6788 70 58.0 7 .75344
80 38 .0 5.07984 80 61.2 8.181216
90 41.0 5.48088 90 64 .3 8.595624
100 43 .5 5 .81508 100 67 .5 9.0234
120 48.0 6 .41664 120 73.0 9 .75864
140 52.5 7.0182 140 77.0 10 .29336
160 57 .0 7.61976 160 81.0 10 .82808
180 61.0 8.15448 180 85 .5 11.42964
200 65 .0 8.6892 200 90.0 12 .0312
225 70.0 9.3576 225 95 .5 12 .76644
250 75 .0 10.0260 250 101.0 13.50168
275 80.0 10.6944 275 104 .5 13 .96956
300 85 .0 11.3628 300 108 .0 14 .43744
400 105 .0 14.0364 400 127 .0 16 .97736
500 124 .0 16.57632 500 143 .0 19.11624
750 170 .0 22 .7256 750 177 .0 23 .66136
1,000 208 .0 27 .80544 1,000 208.0 27.80544
1,250 239.0 31.94952 1,250 239 .0 31 .94952
1,500 269 .0 35 .95992 1,500 269 .0 35 .95992
1,750 . 297 .0 39.70296 1,750 297 .0 39 .70296
(Cor1ti11u ed)
2000 INTERNATIONAL PLUMBING CODE<' 117
2" Waterline -Gateway Center
Hazen-Williams Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Length ......................... .
Coefficient .................... .
Computed Results:
Headloss ....................... .
Area ........................... .
Perimeter ...................... .
Velocity ....................... .
Circular
Headloss
2.0000 in
0.2300 cfs
10.0000 ft
150.0000
1. 7894 ft
0.0218 ft2
6.2832 in
10.5424 fps
Attn. John LOAD ANALYSIS
GATEWAY RETAIL CENTER
Gas Water Heater and Heating-System
120/208 Volt 3 Phase
CENTER SP ACE Builders Showroom 3;556 Square F-eet
CATEGORY
Lighting
General Receptacles 120v
Lighting Display Plgs 120v
(on ceiling)
Motors-Exhaust Fans 120v
(incl 1.25%)
CONNECTED LOAD
8303w
6600w
8l00w
4800w
DETAIL
.g ReeeMed X 120w= %0w
12 2X4 Flour X l04wcl248w
6 Flour Strip X 55w= 330w
3 Exits X SSw= 16.5w
.56 Geo lncand X l0Qw=560Qw
Total =83(J3w
3 7 x l&Ow = 6660w
27 X 300w... 8l00w
3 x r6oo-= 480ffw
Kit-Display Oven Pigs 208v 2 pole HJOOOw 2 X SO<JOw"" 11JOOOw
#1 Heating(fan only) l20v
#2 Heating (fan only) f20v
# 1 Cooling 208v 3 phase
#2 Cooling 208v 3 phase
HOUSE PANEL
16SOw
t680W
lm'Ow
ll250w
IX 1680w = 1680w
IX I 680w • 1:680w
ix n zs-ow.=-rr2s0w
[ (25 running amps) X l .25 %]
1xl1250w=l 1250w
[ (25 running amps) X I .2S-%J
Total 63723w =177 AblpS (17.92w per Sq Ft)
Total 8558w = 23 Amps
3-400w MH/473W ea= 14.34w
6-lSOw MW104wea= 6Z4w
20-lOOw Inamit IOOw-e&= 2UOOw
3-WP GF1 Pigs lSOOw ea= 4SOOw
ONE SPACE EACH SIDE 1977 Sq Ft each Empty Spac.e-Not Yet Leased =Total 3954 Sq Ft
Totaf 70855w =l97 Amps EstiinateaI:oruf (&ase<fon cen1en;paceJ
l 7 .92w per Sq Ft= 7i>SS5w
UIEl«trfc
JSS Morino Rd
Phol( ftW 778·31441
Total 143136w =3• Amps ConnecfedLolOf No Demand Factor
' J
Drainage Report
for
Gateway Retail Center
College Station, Texas
February 2004
Developer:
Todd Carnes
College Station, Texas
(979) 693-7835
Prepared By:
TEXCON General Contractors
1707 Graham Road
College Station, Texas 77845
(979) 764-7743
CERTIFICATION
I, Joseph P. Schultz, Licensed Professional Engineer No . 65889, State of Texas , certify that this report
for the drainage design for the Gateway Retail Center in College Station, Texas, was prepared by me in
accordance with the provisions of the City of College Station Drainage Policy and Design Standards
for the owners hereof, with the exception that storm water runoff detention is not being required at this
site since the site discharges directly into a storm sewer system which discharges into the existing
detention facility for the entire Gateway Development.
TABLE OF CONTENTS
GATEWAY RETAIL CENTER
CERTIFICATION .................................................................................................................................................................. 1
TABLE OF CONTENTS ........................................................................................................................................................ 2
LIST OF TABLES .................................................................................................................................................................. 2
INTRODUCTION ................................................................................................................................................................... 3
GENERAL LOCATION AND DESCRIPTION .................................................................................................................. 3
DEVELOPMENT DRAINAGE PATTERNS ....................................................................................................................... 3
DRAINAGE DESIGN CRITERIA ........................................................................................................................................ 3
STORM WATER RUNOFF DETERMINATION .............................................................................................................. .4
STORM SEWER PIPE & INLET DESIGN ........................................................................................................................ .4
DETENTION FACILITY ...................................................................................................................................................... 5
CONCLUSIONS ..................................................................................................................................................................... 5
APPENDIX A .......................................................................................................................................................................... 6
Calculations
EXHIBIT ............................................................................................................................................................................... 11
Sheet S3 -Drainage and Grading Plan
LIST OF TABLES
TABLE 1 -Rainfall Intensity & Runoff Data ..................................................................................... 4
TABLE 2 -Runoff Data ......................................................................................................................... 4
DRAINAGE REPORT
GATEWAY RETAIL CENTER
INTRODUCTION
T he purpose of this report is to provide th e hydrolo g ical effect s of the construction of th e
infras tructure for th e Gatew a y Re tail C enter proj ec t , and to sh o w that th e stonn w at er run off
w ill be controlled in such a manner so as to have minimal offs it e or downstre a m impact.
GENERAL LOCATION AND DESCRIPTION
The project is located on approximately 1.5 acres located in the Gateway Dev e lopment in
College Station, Texas . The site is a portion of Block 1, Lot 2R of the Phase 1 of the Gatew ay
Subdivision. The project will be developed in 2 phases with approximately 0 .8 acres being
developed in Phase 1. This site has previously been developed with the clearing and grading
completed with the Home Depot project. In addition, the site has previously constructed
driveways on all four sides, some of which are on this tract. The site falls approximately 6 ' in
elevation from the west side to east side of the site .
DEVELOPMENT DRAINAGE PATTERNS
The storm water runoff from the site flows into an ex isting storm sewer inlet at the north comer
of the site. The post development drainage area boundary for both phases is shown on Sh eet
S3 , the Drainage and Grading Plan. The grading plan is based on elevations relative to the site
with the existing grate Inlet No. 1 top assumed to be Elevation 100, as shown on the plans .
This inlet is located in the existing driveway south of the site . The existing storm sewer inlet
was constructed with the Home Depot development located to the north of this site . The
Drainage/Detention Report for the Home Depot development was prepared in August 2002 by
Bury + Partners -SA, Inc. A review of this report shows that this site is part of Drainage Area
7, which had an area of 2.5 acres , a "c" value of 0.85 , and a time of concentration, Tc , valu e of
10 minutes . This area included a portion of Lot 2R to the east of this site, which is be in g
developed separately and will have its own storm sewer system.
DRAINAGE DESIGN CRITERIA
The design parameters for the storm sew er are as follows:
• The Rational Method is utili z ed to determine peak storm water runoff rates for th e
storm sewer design.
• Desi gn Storm Frequency
Stonn sewer s ystem
• Runo ff Co e ffici ents
10 and 100 -ye ar storms eve nt s
Landscap e areas C = 0 .60
Imp e rv ious s ur fa ces C = 0 .9 0
• Rain fa ll Int ensit y equati o ns and va lu es for Bra zos C ount y ca n be fo und in Ta bl e I .
• Tim e o f C onc e ntrati o n, le -Fo r s ma ll e r drain age a reas , a minimum tc of I 0 minut es is
use d to determin e th e ra in fa ll int e ns it y va lu es.
' ·'
TABLE 1 -Rainfall Intensity & Runoff Data
Rainfall Intensity Values
(in/hr)
Storm t c =
Event 10 min
Is 7 .693
110 8 .635
'2s 9 .861
lso 11 .148
1100 11.639
Brazos
County:
5 year storm 10 year storm
b= 76 b= 80
d= 8.5 d= 8 .5
e= 0.785 e= 0.763
I = b I {tc+d)e
I = Rainfall Intensity (in/hr)
tc = L/(V*60)
tc = Time of concentration (min)
L = Length (ft)
V = Velocity (ft/sec)
25 year storm 50 year storm 100 year storm
b= 89 b= 98 b= 96
d = 8.5 d = 8.5 d= 8.0
e= 0.754 e= 0.745 e= 0.730
(Data taken from State Department of Highways and Public Transportation Hydraulic Manual, page 2-16)
STORM WATER RUNOFF DETERMINATION
The peak runoff values were determined in accordance with the criteria presented in the
previous section for the 10-and 100-year storm events. The runoff coefficients are based
on the development of both phases of this site. The drainage area is shown on Sheet S3,
The Drainage and Grading Plan. Runoff conditions are summarized in Table 2.
TABLE 2 -Runoff Data
Area Size Composite 110 010
acres C in/hr cfs)
f--~~~--+-~'--~-'---+-~~~~-t----'-~-'---t~--'-
Area No.
1. 01 0 .85 8 .64 7.42
STORM SEWER PIPE & INLET DESIGN
1100
(in/hr)
11 .64
0100
(cfs)
9 .99
The existing private storm sewer Inlet No. 2 will be relocated ap pro ximately 25 feet to the
north of where it is currently located so that the proposed building can be constructed. A
30" diam eter storm sewer pipe will be constructed from the relocated inlet to the existing
storm sewer junction box. This relocated storm sewer inlet (proposed storm sewer Inlet
No. I) will collect the runoff from both phases of this project. The runoff from the Phase I
building roof wi ll be collected by a roof gutter system and discharged at the inlet. Th e
Phase 2 building and most of the parking lot will drain to a concrete flume that is located
along the north side of the Phase I building . A portion of the project site will drain
direct ly into the existing driveway a lon g the southern boundary of the site . This runoff
wi ll eventua ll y enter the public storm se we r system thro ugh the ex ist in g inlets locat ed in
th e ex istin g dri ve w ay s .
..j
The grate for the existing storm sewer inlet is a 36" x 36" V-5736 grate manufactured by
East Jordan Iron Works . The open area for the grate is 693 square inches, or 4 .81 square
feet (sf). Assuming the grate is 50% clogged , the available open area is 2.4 sf.
The depth of water above the grate is determined by the orifice equation :
Q = 4.82* Ag * y 112
Therefore, for the 10-and 100-year storm events the following depths are calculated:
Q1 0 = 7.42 cfs ~ y = 0.41' = 4.9"
Qioo = 9.99 cfs ~ y = 0.75' = 9.0 "
The top of the grate is proposed to be at elevation 2~8.5, and the top of the berm around
the inlet will be elevation 100.0. There will be 9" of freeboard during the 100-year storm
event.
The proposed flume and storm sewer pipe design parameters and summaries are found in
Appendix A. The flume will be 4' wide and have a 6" high curb on each side. The depth
of flow for the flume is 4" and 4 .8" for the 10-year and 100-year storm events,
respectively. The storm sewer pipe size was selected to be 30" diameter because.it is the
same as the existing pipe diameter. The flowline into the existing junction box will match
the existing pipe flow line. The velocity in this pipe will be 6 .0 fps and 6.5 fps for the 10-
year and 100-year storm events, respectively.
DETENTION FACILITY
No storm water detention is required for this site because the existing private and public
storm sewer systems and the Home Depot detention pond were designed for the full
development of the entire Gateway Subdivision development. The design of the facilities
is provided in the aforementioned Drainage/Detention Report prepared by Bury + Partners .
CONCLUSIONS
The construction of this project will increase the storm water runoff from this site .
However, the runoff will be carried through the proposed and existing storm sewer system
and into the existing detention pond. No flood damage to downstream or adjacent
landowners is expected as a result of this development.
5
APPENDIX A
Calculations
Concrete Flume -10-yr Storm
Channel Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Height ......................... .
Bottom width ................... .
Computed Results:
Depth .......................... .
Velocity ....................... .
Flow area ...................... .
Flow perimeter ................. .
Hydraulic radius ............... .
Top width ...................... .
Area ........................... .
Perimeter ...................... .
Percent full ................... .
Rectangular
Depth of Flow
7.4200 cfs
0.0130 ft/ft
0.0130
6.0000 in
48.0000 in
3.9599 in
5.6213 fps
1.3200 ft2
55.9199 in
3.3991 in
48.0000 in
2.0000 ft2
60.0000 in
65.9991 %
Concrete Flume -100-yr Storm
Channel Calculator
Given Input Data:
Sha pe .......................... .
Solving for .................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Height ......................... .
Bot tom width ................... .
Computed Results:
Depth .......................... .
Velocity ....................... .
Flow area ...................... .
Flow perimeter ................. .
Hydraulic radius ............... .
Top width ...................... .
Area ........................... .
Perimeter ...................... .
Percent full ................... .
Rectangular
Dep th of Flow
9.9900 cfs
0.0130 ft /ft
0 .0130
8.0 000 in
48 .0000 in
4.7892 in
6.25 78 fps
1.5964 ft2
57 .5784 in
3.9925 in
48.0000 in
2.6667 ft2
64.0000 in
59.8651 %
30 11 Storm Sewer -10 -yr Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
30 .0000 in
7.4200 cfs
0.0100 ft/ft
0.0 140
8.9759 in
4.9087 ft2
1.2339 ft2
34.7257 in
94.2478 in
6.0132 fps
5.1169 in
29.9195 %
38.0873 cfs
7.7591 fps
30" Storm Sewer Pipe -100-yr Storm
Manning Pipe Calcula to r
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
30.0000 in
9.9900 cfs
0.0100 ft/ft
0.0140
10.4863 in
4.9087 ft2
1.5284 ft2
37.9543 in
94.2478 in
6.5363 fps
5.7988 in
34.9542 %
38.0873 cfs
7.7591 fps
'
EXHIBIT
Sheet 83 -Drainage and Grading Plan
11
I
~-ti DEVELOPMENT PERMIT
PERMIT NO . 04-05
Project: GATEWAY RETAIL CENTER
COLllC.l STATION FOR AREAS INSIDE THE SPECIAL FLOOD HAZARD AREA
RE : CHAPTER 13 OF THE COLLEGE STATION CITY CODE
SITE LEGAL DESCRIPTION:
The Gateway
Lots 2RA and 2RC
DATE OF ISSUE: 04/14/04
OWNER:
Baker and Carnes Investments c/o Todd Carnes
230 Southwest Parkway East
College Station , Texas 77840
SITE ADDRESS:
730 Earl Rudder Freeway South
DRAINAGE BASIN:
Burton Creek
VALID FOR 9 MONTHS
CONTRACTOR:
TYPE OF DEVELOPMENT: Full Development Permit
SPECIAL CONDITIONS:
All construction must be in compliance with the approved construction plans
All trees required to be protected as part of the landscape plan must be completely barricaded in accordance with Section
7.5.E., Landscape/Streetscape Plan Requirements of the City's Unified Development Ordinance , prior to any operations of
this permit. The cleaning of equipment or materials within the drip line of any tree or group of trees that are protected and
required to remain is strictly prohibited . The disposal of any waste material such as , but not limited to , paint, oil , solvents,
asphalt , concrete , mortar, or other harmful liquids or materials within the drip line of any tree required to remain is also
prohibited .
TCEQ PHASE II RULES IN EFFECT
The Contractor shall take all necessary precautions to prevent silt and debris from leaving the immediate construction site
in accordance with the approved erosion control plan as well as the City of College Station Drainage Policy and Design
Criteria . If it is determined the prescribed erosion control measures are ineffective to retain all sediment onsite , it is the
contractors responsibility to implement measures that will meet City , State and Federal requirements . The Owner and/or
Contractor shall assure that all disturbed areas are sodden and establishment of vegetation occurs prior to removal of any
silt fencing or hay bales used for temporary erosion control. The Owner and/or Contractor shall also insure that any
disturbed vegetation be returned to its original condition , placement and state . The Owner and/or Contractor shall be
responsible for any damage to adjacent properties , city streets or infrastructure due to heavy machinery and/or equipment
as well as erosion , siltation or sedimentation resulting from the permitted work.
In accordance with Chapter 13 of the Code of Ordinances of the City of College Station, measures shall be taken to insure
that debris from construction , erosion , and sedimentation shall not be deposited in city streets , or existing drainage
fac iliti es .
I hereby grant this permit for development of an area inside the special flood hazard area . All development shall be in
accordance with the plans and specifications submitted to and approved by the City Engineer in the development permit
application for the above named project and all of the codes and ordinances of the City of College Station that apply .
DL-}-JL/-D'-f
Date Lf-)S--Ol(
Owner/Agent/Contractor Date
Drainage Report
for
Gateway Retail Center
College Station, Texas
February 2004
Developer:
Todd Carnes
College Station, Texas
(979) 693-7835
Prepared By:
TEXCON General Contractors
1707 Graham Road
College Station, Texas 77845
(979) 764-7743
CERTIFICATION
I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report
for the drainage design for the Gateway Retail Center in College Station, Texas, was prepared by me in
accordance with the provisions of the City of College Station Drainage Policy and Design Standards
for the owners hereof, with the exception that storm water runoff detention is not being required at this
site since the site discharges directly into a storm sewer system which discharges into the existing
detention facility for the entire Gateway Development.
JosI>:SChultz, P.E .
TABLE OF CONTENTS
GATEWAY RETAIL CENTER
CERTIFICATION .................................................................................................................................................................. 1
TABLE OF CONTENTS ........................................................................................................................................................ 2
LIST O F TABLES .................................................................................................................................................................. 2
INTRODUCTION ................................................................................................................................................................... 3
GENERAL LOCATION AND DESCRIPTION .................................................................................................................. 3
DEVELOPMENT DRAINAGE PA TTERNS ....................................................................................................................... 3
DRAINAGE DESI GN C RITERIA ........................................................................................................................................ 3
STORM WATER R UN OFF DETERMINATION .............................................................................................................. .4
STORM SEWER PIPE & INLET DESIGN ........................................................................................................................ .4
DETENTION FACILITY ...................................................................................................................................................... 5
CONCLUSIONS ..................................................................................................................................................................... 5
APPENDIX A .......................................................................................................................................................................... 6
Calculations
EXHIBIT ............................................................................................................................................................................... 11
Sheet S3 -Drainage and Grading Pla11
LIST OF TABLES
TABLE 1 -Rainfall Intensity & Runoff Data ..................................................................................... 4
TABLE 2 -Runoff Data ......................................................................................................................... 4
DRAINAGE REPORT
GATEWAY RETAIL CENTER
INTRODUCTION
The purpose of this report is to provide the hydrolo g ical effects of the construction of th e
infrastructure for the Gateway Retail C enter project , and to show that th e stom1 water runoff
will be controlled in such a manner so as to have minimal offsite or downstream impact.
GENERAL LOCATION AND DESCRIPTION
The project is located on approximately 1.5 acres located in the Gateway Development in
College Station, Texas . The site is a portion of Block 1, Lot 2R of the Phase l of the Gateway
Subdivision. The project will be developed in 2 phases with approximately 0.8 acres being
developed in Phase 1. This site has previously been developed with the clearing and grading
completed with the Home Depot project. In addition, the site has previously constructed
driveways on all four sides , some of which are on this tract. The site falls approximately 6 ' in
elevation from the west side to east side of the site.
DEVELOPMENT DRAINAGE PATTERNS
The storm water runoff from the site flows into an existing storm sewer inlet at the north corner
of the site. The post development drainage area boundary for both phases is shown on Sheet
S3 , the Drainage and Grading Plan . The grading plan is based on elevations relative to the site
with the existing grate Inlet No. 1 top assumed to be E levation 100 , as shown on the plans .
This inlet is located in the existing driveway south of the site. The existing storm sewer inlet
was constructed with the Home Depot development located to the north of this site. The
Drainage/Detention Report for the Home Depot development was prepared in August 2002 by
Bury+ Partners -SA, Inc. A review of this report shows that this site is part of Drainage Area
7, which had an area of 2.5 acres, a "c" value of 0.85 , and a time of concentration, Tc , value of
10 minutes . This area included a portion of Lot 2R to the east of this site, which is being
developed separately and will have its own storm sewer system.
DRAINAGE DESIGN CRITERIA
The design parameters for the storm sewer are as follows :
• The Rational Method is utilized to determine peak storm water runoff rates for the
stonn sewer design.
• Design Storm Frequency
Storm sewer system
• Runoff Coefficients
10 and 100-year storms ev ents
Landscap e ar eas C = 0 .60
[mperv ious s urfaces C = 0 .90
• Rainfall int ensit y equations and va lu es for Br az o s C ount y can be found in T a bl e I .
• Tim e of C oncentration , tc -For s ma ll e r draina ge a reas, a minimum t, of I 0 minut es is
use d to de termin e th e ra infall int e ns it y va lu es.
·'
TABLE 1 -Rainfall Intensity & Runoff Data
Rainfall Intensity Values
(in/hr)
Storm le=
Event 10 min
Is 7.693
110 8.635
hs 9.861
lso 11 .148
1100 11 .639
Brazos
County:
5 year storm 10 year storm
b= 76 b= 80
d= 8.5 d = 8.5
e= 0.785 e= 0 .763
I = b I (tc+d)e
I = Rainfall Intensity (in/hr)
tc = U(V*60)
tc =Time of concentration (min)
L = Length (ft)
V = Velocity (ft/sec)
25 year storm 50 year storm 100 year storm
b= 89 b= 98 b= 96
d= 8.5 d= 8.5 d= 8.0
e= 0.754 e= 0.745 e= 0.730
(Data taken from State Department of Highways and Public Transportation Hydraulic Manual, page 2-16)
STORM WATER RUNOFF DETERMINATION
The peak runoff values were determined in accordance with the criteria presented in the
previous section for the 10-and 100-year storm events. The runoff coefficients are based
on the development of both phases of this site. The drainage area is shown on Sheet S3 ,
The Drainage and Grading Plan. Runoff conditions are summarized in Table 2.
TABLE 2 -Runoff Data
Area Size Composite 110
acres C in/hr)
t--~~~--+~~~-'--+-~~~~+-~~
Area No.
1.01 0 .85 8.64
STORM SEWER PIPE & INLET DESIGN
010
(cfs)
7.42
1100
(in/hr)
11.64
0100
(cfs)
9.99
The existing private storm sewer Inlet No. 2 will be relocated approximately 25 feet to the
north of where it is currently located so that the proposed building can be constructed. A
30" diameter storm sewer pipe w ill be constructed from the relocated inlet to th e existing
storm sewer junction box. This relocated storm sewer inlet (proposed storm sewer Inlet
No. 1) will collect the runoff from both phases of this project. The runoff from the Phas e 1
building roof wi ll be collected by a roof gutter system and discharged at the inl et. The
Phase 2 building and most of th e parkin g lot will drain to a co ncrete flume th at is lo cated
a long th e north side of the Phase 1 building. A portion of the project site w ill drain
directly into the existing dri ve way a lon g the southern bound a r y of th e site. This runoff
w ill eventual ly enter the publ ic stom1 sewe r system through the ex istin g inl ets loca ted in
the ex ist in g dri veways .
-l
The grate for the existing storm sewer inl et is a 36 " x 36" V-5736 grat e manu fa ctured by
East Jordan Iron Works . The open area for the grat e is 693 square inch es, or 4 .81 square
fe et (sf). Assuming th e grate is 50 % clo gge d , the av ailable op en area is 2.4 sf.
T he depth of water above the grate is determined by the orific e equation :
Q = 4 .82 * Ag * y 112
Therefore, for the 10-and 100-year storm events th e followin g depths are calcul ated:
Q1 0 = 7.42 cfs ~ y = 0.41 ' = 4 .9"
Qi oo = 9 .99 cfs ~ y = 0 .75 ' = 9.0 "
T he top of the grate is proposed to be at elevation 298 .5, and the top of the berm around
the inlet will be elevation 100 .0 . There will be 9" of freeboard during the 100-year storm
event.
The proposed flume and storm sewer pipe design parameters and summaries are found in
Appendi x A. The flume will be 4' wide and have a 6" high curb on each side . The depth
of flow for the flume is 4" and 4.8 " for the 10-year and 100-year storm events ,
respectively. The storm sewer pipe size was selected to be 30" diameter because .i t is the
same as the existing pipe diameter. The flow line into the existing junction box will match
the existing pipe flowline . The velocity in this pipe will be 6 .0 fps and 6 .5 fps for the 10-
year and 100-year storm events, respecti v ely.
DETENTIO N FACILITY
No storm water detention is required for this site because the ex isting private and public
storm sewer systems and the Home Depot detention pond were designed for the full
development of the entire Gateway Subdivision development. The design of the facilities
is provided in the aforementioned Drainage/Detention Report prepared by Bury+ Partners.
CONCLUSI ONS
The construction of this project will increase the storm water runoff from this site .
However, the runoff will be carried throu gh the proposed and existing storm sewer system
and into the existing detention pond. No flood damage to downstream or adj acent
landowners is expected as a result of this developm ent.
APPENDIX A
Calculations
Concrete Flume -1 0-yr Storm
Channel Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Height ......................... .
Bot tom width ................... .
Computed Resul ts:
Depth .......................... .
Velocity ....................... .
Flow area ...................... .
Flow perimeter ................. .
Hydraulic radius ............... .
Top width ...................... .
Area ........................... .
Perimeter ...................... .
Percent f ul 1 ................... .
Rectangular
Depth of Flow
7.4200 cfs
0.0130 ft/ft
0 .01 30
6.0000 in
48.0000 in
3 .959 9 in
5 .621 3 fps
1.3200 ft2
55 .91 99 in
3 .3991 in
48.0000 in
2.0000 ft2
60.0000 in
65.9991 %
Concrete Flume -100-yr Storm
Channel Calculator
Given Input Data :
Shape .......................... .
Solving for .................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Height ......................... .
Bot torn width ................... .
Computed Results:
Depth .......................... .
Velocity ....................... .
Flow area ...................... .
Flow perimeter ................. .
Hydraulic radius ............... .
Top width ...................... .
Area ........................... .
Perimeter ...................... .
Percent full ................... .
Rectangular
Depth of Flow
9.9900 cfs
0 .01 30 ft/ft
0.0 130
8.0000 in
48.0000 in
4.7892 in
6.2578 fps
1.5964 ft2
57.5784 in
3.9925 in
48.0000 in
2.6667 ft2
64.0000 in
59.8651 %
30" Storm Sewer -10-yr Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
30.0000 in
7.4200 cfs
0.0100 ft/ft
0.0140
8.9759 in
4.9087 ft2
1.2339 ft2
34.7257 in
94.2478 in
6.0132 fps
5.1169 in
29.9195 %
38.0873 cfs
7.7591 fps
30" Storm Sewer Pipe -100-yr Storm
Manning Pipe Ca lculat or
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
30.0000 in
9.9900 cfs
0.0100 ft/ft
0.0140
10.4863 in
4.9087 ft2
1.5284 ft2
37.9543 in
94.2478 in
6.5363 fps
5.7988 in
34.9542 %
38.0873 cfs
7.7591 fps
• 4
EXHIBIT
Sheet S3 -Drainage and Grading Plan
11
FOR OFFICE USE ONLY
P&Z CASE NO .: -----
SITE PLAN APPLICATION
MINIMUM SUBMITTAL REQUIREMENTS
. /Site plan application completed in full.
-y;T $200.00 Application Fee .
'7"" $200 .00 Development Permit Application Fee.
DATE SUBMITTED:
__ $600 .00 Public Infrastructure Inspection Fee if applicable . (This fee is payable if construction of a public
waterline, sewerline, sidewalk, street or drainage facilities is involved.)
V Eleven (11) folded copies of site plan ·
__ One (1) folded copy of the landscape plan.
__ One (1) copy of building elevation required.for buildings with a footprint of 20,000 sq . ft . or greater
__ A list of building materials for all facades that are visible from the public right-of-way .
__ A copy of the attached site plan checklist with all items checked off or a brief explanation as to why they
are not checked off.
__ Parkland Dedication requirement approved by the Parks & Recreation Board, please provide proof of
approval (if applicable).
Date of Preapplication Conference: ______________________ _
NAME OF PROJECT C2:>q.\e~c) \<..e.,-\:.~.\ [<:CJ\.er
ADDRESS ___ --:-----------------------------
LEGAL 0EscR1rT10N Lo\ cl.\{ c_ b \ \z. \
APPLICANT/PROJECT MANAGER'S INFORMATION (Primary Contact for the Project):
Name \. (__ ('(\.e~
Street Address ;;13,0 Sbv...~~e~\
State '\-X Zip Code 1 Jiyo
Phone Number kf\3-:)i~
PROPERTY OWNER'S INFORMATION :
a..rK~ ~\; City \Ci '"-
E-Mail Address ~C...o.. t C\e. s ~tc._c ('\. \:v\<!. . <\e.. \-
Fax Number lsf\~-'li~C\
Name ~ e_~ -.S:.'<'-~~\~c.1\-\s LL c_
StreetAddress 9-ZC ~~\AC<?.~\ 9o..rY,~ 1:_o...~\-City \\ene. ~\~\.\o"
State '1:-J< Zip Code 71 &YD E-Mail Address ------------
Phone Number lo:\. ~-J 87:>S" Fax Number _lcB___,'-"~"---1....:....8=-'::f\-=-..J.__ ______ _
ARCHITECT OR ENGINEER'S INFORMATION:
Name Rf\!::._ ~\~"
Street Address -----------------
State "'\--"')( Zip Code 71~4 ~ E-Mail Address ------------
Phone Number _1_~_'4_-_'J~l_S'_D ___ _ Fax Number -------------
6/13/03 I of6
"OTHER CONTACTS (Please specify type of contact, i.e . project manager, potential buyer, local contact , etc .)
Name ---------------------------------
Street Address -----------------City ----------
E-Mail Address State _____ Zip Code _____ _ ------------
Phone Number -----------Fax Number ____________ _
PRESENT USE OF PROPERTY --------------------------
PROPOSED USE OF PROPERTY
VARIANCE(S) REQUESTED AND REASON(S) ------------------
#OF PARKING SPACES REQUIRED l._\S. la"-\ #OF PARKING SPACES PROVIDED l\lo
MUL Tl-FAMILY RESIDENTIAL PARKLAND DEDICATION
Total Acreage ____ _ # of Multi-Family Dwelling Units
Floodplain Acreage __ _ ---x $452 = $ --------
Housing Units ____ _ _ __ # of acres in floodplain
# of 1 Bedroom Units # of acres in detention ------
# of 2 Bedroom Units ---__ # of acres in greenways
#of 3 Bedroom Units ---__ date dedication approved by Parks Board
#of 4 Bedroom Units COMMERCIAL ---
FOR 2 BEDROOM UNITS ONLY Total Acreage • ~~ \
___ #Bedrooms= 132 sq . ft . Building Square Feet '6 a~ \
___ # Bedrooms < 132 sq . ft. Floodplain Acreage _____ _
NOTE: Parkland Dedication fee is due prior to the issuance of a Building Permit.
The applicant has prepared this application and certifies that the facts stated herein and exhibits attached
hereto are true and correct.
Signature of Owner, Agent or Applicant Date
6/13/03 2 of 6
.. SUPPLEMENTAL DEVELOPMENT PERMIT INFORMATION
Application is hereby made for the following development specific site/waterway alterations:
ACKNOWLEDGMENTS:
I, ___ \_,_&1=-:=.....__(h~. ~(-~~~~3~-----' design engineer/owner, hereby acknowledge or affirm that:
The information and conclusions contained in the above plans and supporting documents comply w ith the current
requ irements of the City of College Station , Texas City Code , Chapter 13 and its associated Drainage Policy and Design
Standards . As a condition of approval of this permit application, I agree to construct the improvements proposed in this
ap 'cation accordi to these documents and the requirements of C ter of the llege Station City Code .
Contractor
CERTIFICATIONS: (for proposed alterations within designated flood hazard areas .)
A.I , certify that any nonresidential structure on or proposed to be on this site
as part of this application is designated to prevent damage to the structure or its contents as a result of flooding from the
100 year storm .
Engineer Date
B. I, certify that the finished floor elevation of the lowest floor , including any
basement, of any residential structure , proposed as part of th is application is at or above the base flood elevation
established in the latest Federal Insurance Administration Flood Hazard Study and maps, as amended .
Engineer Date
C . I, , certify that the alterations or development covered by this permit shall
not diminish the flood-carrying capacity of the waterway adjoining or crossing this permitted site and that such alterations
or development are consistent with requirements of the City of College Station City Code, Chapter 13 concerning
encroachments of floodways and of floodway fringes .
Eng ineer Date
D. I, , do certify that the proposed alterations do not raise the level of the 100
year flood above elevation established in the latest Federal Insurance Administration Flood Hazard Study.
Engineer Date
Conditions or comments as part of approval : --------------------------
In accordance with Chapter 13 of the Code of Ordinances of the City of College Station, measures shall be
taken to insure that debris from construction, erosion, and sedimentation shall not be deposited in city streets,
or existing drainage facilities .
All development shall be in accordance with the plans and specifications submitted to and approved by the City Engineer
for the above named project. All of the applicable codes and ordinances of the City of College Station shall apply.
6/13103 3 of 6