HomeMy WebLinkAboutDrainage AnalysisREDMOND SHOPPING CENTER
1530 TEXAS AVENUE
DRAINAGE ANALYSIS
Revised - March 2013
Prepared for:
BKXL PARTNERS NO.2, LTD.
6363 WOODWAY DRIVE
HOUSTON, TExAS 77057
Submitted to
(* C` OF COLt.wr STNFI ON
else heart of the Rettarch Vd ley
By
MITCHELL
I V-41 I
MORGAN
ENGINEERS & CONSTRUCTORS
511 UNIVERSITY DRIVE, SUITE 204
COLLEGE STATION, TX 77840
OFFICE (979) 260-6963
FAx (979) 260-3564
CERTIFICATION
This report for the drainage design for Redmond Shopping Center was prepared under
my supervision in accordance with provisions of the Bryan/College Station Unified
Drainage Design Guidelines for the owners of the property. All licenses and permits
required by any and all state and federal regulatory agencies for the proposed drainage
improvements have been issued.
Registered Professional Engineer
State of Texas No. 77689
Redmond Shopping Center
1530 Texas Avenue
Drainage Report
Revised - February 2013
The project site is located on Lot 9R, Block 3, of the Redmond Terrace First Installment on the north
corner of Texas Avenue and Redmond Drive as seen on Exhibit 1. The development will consist of a
8,640 square foot building with a 541 square foot outdoor patio area and required parking lot. The
proposed site plan is illustrated in Exhibit 1.
The project site was previously used as a gas station and car wash site. When these uses were
abandoned all of the impervious cover remained on the lot. These old parking and building slabs will be
removed as part of this redevelopment project.
The following report has been prepared to illustrate the drainage design for this redevelopment and its
impact to the adjoining drainage systems. The project site currently consists of 4 drainage areas, EA1
thru EA4, all of which discharge ultimately into the Texas Avenue storm sewer system. EA1 is
approximately 0.35 acres and was the site of the old gas station. This site had no subsurface drainage
system and the drainage areas simply sheet flowed and discharged thru the old curb cut toward the
intersection of Redmond and Texas Avenue. EA4 is approximately 0.01 acres and is still part of the old
gas station site but it flows directly into the gutter line of Texas Avenue. The runoff from both of these
areas enters the inlet at the intersection of Redmond and Texas Avenue.
Drainage area EA2 and EA3 are located on the old car wash site. Although this site had several grate
inlets and a storm sewer system it did not capture storm sewer runoff from the site. Rather these grate
inlets and storm drains captured just the wash water and ran it through a grit and sand chamber then to
the sanitary sewer system. EA2 is approximately 0.60 acres and runoff from this area discharged as
sheet flow out the 2 driveways onto Redmond Drive. EA3 was also part of the car wash site and was the
grassy area between the impervious cover and the curb. It discharged directly into the gutter of
Redmond Drive. Both of these areas discharged down the gutter in Redmond Drive to the same inlet on
Texas Avenue as the runoff from Drainage Areas EA1 and EA2.
Pre -development drainage areas are provided in Exhibit 2 and their corresponding flows can be found in
Table 1.
Redmond Shopping Center Page 1
Table 1 - Pre -Development Peak Discharges
w
W
Q
a 0
W
_J
.-
o
0
Q
<
y W
W
fa
(LU �
N
o
f7
N
O
-
f7
0
-
Ci
Z
1-
W
W
Q
Q
�
p
O
a
0
NO.
AC.
0.40 0.7
0.95
min
In/Hr
cfs
InIHr
cfs
In/Hr
cfs
InIHr
cfs
In/Hr
cfs
DA-E-01
0.35
0.02 0.00
0.33
0.32
10.0
6.33
2.0
8.6
2.7
9.9
3.1
11.1
3.5
12.5
4.0
DA-E-02
0.60
0.04 0.00
0.56
0.55
10.0
6.33
&5
8.6
4.8
9.9
5.4
11.1
6.1
12.5
6.9
DA-E-03
0.00
0.00 0.00
0.00
0.00
10.0
6.33
0.0
8.6
0.0
9.9
0.0
11.1
0.0
12.5
0.0
DA-E-04
0.01
0.00 0.00
0.01
0.01
10.0
6.33
0.1
8.6
0.1
9.9
0.1
11.1
0.1
12.5
0.1
The post development design of the site will include several on -site storm sewer systems. Roof drains
will discharge through sidewalk trench grates. Runoff will then exit the Redmond driveway to the gutter
and then to the Texas Avenue storm inlet. In addition the front parking lot will be picked up in a 5 foot
storm inlet and will discharge into the back of the storm inlet on Texas Avenue. This can be seen in
Exhibit 1.
The post development drainage design consists of 9 drainage areas, which can be seen in Exhibit 3. PA1-
3 consists of the roof areas of the building. These will discharge through sidewalk trench grates into the
parking lot at the rear of the building and then out the Redmond driveway into the gutter line of
Redmond Drive. Drainage area PA4 is the front parking lot which drains toward the intersection of
Redmond Drive and Texas Avenue where it is picked up in a 5 foot inlet and piped to the back of the
storm inlet on Texas Avenue. Drainage area PAS is the rear parking lot and it discharges out the
Redmond Drive driveway in a similar fashion to the old car wash site. Drainage areas PA 6, 7 and 8 are
all grassy/sidewalk areas outside the developed area of the Redmond Shopping Center. Drainage areas
PA6 & 7 discharge directly to the gutter of Redmond Drive while PA8 discharges directly to the Texas
Avenue gutter. PA 9 encompasses the drainage area next to the outdoor patio as well as a portion of
the outdoor patio. This area drains to a grate inlet adjacent to the outdoor patio which then drains
subsurface to the back of a storm inlet on Texas Avenue. Post -development peak discharges are
provided in Table 2 below.
Redmond Shopping Center Page 2
Table 2 - Post -Development Peak Discharges
a
LU
a
W
�z=
a
gy
J
L)Fo
~oa
N
O
N
hWuj
C
p
_j
O
CY
Ci
a>
W
<
F
O
Lu
a
0
NO.
AC.
0.40 0.7
0.95
min
In/Hr
cfs
In/Hr
cfs
In/Hr
cfs
I In/Hr
I cfs
In/Hr
I cfs
DA-P-01
0.07
0.00 0.00
0.07
0.07
10.0
6.33 _
0.4
8.6
0.6
9.9
0.7
11.1
0.7
12.5
0.8
_ _
0.4
DA-P-02
0.06
0.00 0.00
0.06
0.06
10.0
6.33
8.6
0.5
9.9
0.6
11.1
0.7
12.5
0.8
DA-P-03
0.07
0.00 0.00
0.07
0.07
10.0
6.33
0.4
8.6
0.6
9.9
0.6
11.1
0.7
12.5
0.8
DA-P-04
0.27
0.01 0.00
0.26
0.25
10.0
6.33
1.6
8.6
2.1
9.9
2.4
11.1
2.7
12.5
3.1
DA-P-05
0.37
0.06 0.00
0.31
0.32
10.0
6.33
2.0
8.6
2.8
9.9
3.2
11.1
3.6
12.5
4.0
DA-P-06
0.02
0.00 0.00
0.02
0.01
10.0
6.33
0.1
8.6
0.1
9.9
0.1
11.1
0.2
12.5
0.2
DA-P-07
0.05
0.00 0.00
0.05
0.04
10.0
6.33
0.3
8.6
0.4
9.9
0.4
11.1
0.5
12.5
0.5
DA-13-08
0.04
0.00 0.00
0.04
0.04
10.0
6.33
0.2
8.6
0.3
9.9
0.4
11.1
0.4
12.5
0.5
DA-P-09
0.02
0.01 0.00
1 0.01
0.01
10.0
6.33
0.1
8.6
0.1
9.9
0.1
11.1
0.1
12.5
0.2
As seen in the pre vs post discharge values shown above as well as the drainage area maps it can be
illustrated that the post development runoff is less than the pre developed runoff from the site. This is
due to the existing concrete on the site and the new site additional landscape areas. The total pre
developed runoff from the site in the 100-year storm event is 11 cfs while the post developed runoff
from that same storm event is 10.9 cfs.
On site there are two storm sewer systems which will capture the onsite drainage and discharge it into
the back of 2 storm inlets on Texas Avenue. The first storm drain line is next to the outdoor patio on the
north end of the site. That system captures runoff from DA-P9, which has minimal runoff but it was not
desirable to let this run over the outdoor patio area.
Redmond Shopping Center Page 3
Table 3 -10 Year Pipe Capacity Calculations
U
d
a
d
a
a
W
o
a
L�
Ex
W
Z
F
F•
°
P,
07
z
C
C
a
F
w
F.
#
#
Ac.
min
yr
#
cfs
%
%
in.
fps
cfs
ft.
min
min
Existing
DA-P-04
SW
0.25
10.5
10
1
2.6
0.16
1.000
15
5.3
6.5
29
0.09
10.58
Existing
DA-P-09
NW
0.01
10.0
10
1
0.1
0.01
1.000
8
3.5
1.2
99
0.48
10.48
As seen in Table 3 this area required an 8 inch pipe at a minimum 1% slope to discharge the 10 year
storm event. Table 4 shows that this same 8 inch pipe can accommodate the 100-year storm event as
well.
The other drainage area which is carried subsurface is DA-1304. A 5 foot inlet picks up DA-1304 and
discharges it thru a 15 inch pipe at a minimum 1% slope to the back of the existing storm inlet on Texas
Avenue. Tables 3 & 4 illustrate the pipe capacities for this storm sewer system.
Table 4 -100 Year Pipe Capacity Calculations
H
W
U
E
o
o
Q
c
d
�,
>
z
OF
+�
c
A
z°
#
#
Ac.
min
yr
#
cfs
%
%
in.
fps
cfs
ft.
min
min
Existing
DA-P-04
SW
0.25
10.5
100
1
3.8
0.34
1.000
15
5.3
6.5
29
0.09
10.58
Existing
DA-P-09
NW
0.01
10.0
100
1
0.2
0.03
1.000
8
3.5
1.2
99
0.48
10.48
Tables 5 & 6 illustrate the sizing of the 5 foot inlet within the parking lot. Both of these storm
events only require a 5 foot inlet to pick up the runoff from DA-PO4.
Redmond Shopping Center Page 4
Table 5 —10-Year Inlet Capacity Calculations
SUMP CURB
(10 Year
Storm
DA-P-04
Q =
2.13
cfs
clog =
10%
Q clogged =
2.34
cfs
=
0.83
ft
L=
1.03
ft
Table 6 —100-Year Inlet Capacity Calculations
SUMP CURB
(100 Year Storm
DA-P-04
Q =
3.08
cfs
clog =
10%
Q clogged =
3.39
cfs
=
0.83
ft
L=
1.50
ft
Table 7 —100-Year Grate Inlet Capacity Calculations
SUMP GRATE
100 Year Storm
DA-P-09
Q =
0.17
cfs
clog =
25%
Q clogged =
0.21
cfs
Inlet Selected=
NDS#771
NDS
Open Area
Selected=
0.09
ftZ
T/G=
299.03
ft
h = 0.21 ft
As seen in Table 7 above, an NDS model #771 grate inlet will handle the 100-year event with minimal
ponded depth (0.21 feet).
Conclusion
As seen in the discussion above, the post developed runoff from the Redmond Shopping Center is less
than pre development runoff rates. All post developed runoff is entering the same storm sewer system
as the predeveloped conditions and all site drainage systems have been designed for the 10 and 100-
year storm events in accordance with the BCS Unified Stormwater Design Guidelines.
Redmond Shopping Center Page 5
Attachments
EXHIBIT 1:
Proposed Overall Site Plan
EXHIBIT 2:
Pre Development Drainage Areas
EXHIBIT 3:
Post Development Drainage Areas
Redmond Shopping Center Page 6
INAMITT 6ENCHMWK: 5/0 Ine1 Iran Pod tocvhtl NW Comer of Plol
GENERAL CONSTRUCTION NOTES:
1. It ¢loll be the meponsisiddy Of the Contractor is verify the -act location of ALL ANE ing underground utilities.
Full.. . Ins Contractor snail drard all utility mmpony rspre—terwas a minimum of 46 Fours m adwnce of any
eawvi ion.
Contact Dig Tes 0 I 600 344-83]]
I, Contact Miles Lavender O Suddemink 846-2229
Conlacl Richard Wallace IT Some- In 4]52
d ... adl Gllbart A,Dr z 0 l) CEO (ELAINA 969-6255
Conlacl Bulcn VA l's ITCSV (Water/Waet... ter) ]54-3660
A F Contact Josh NOTon O nnew Gas (Gas) all
2. All ....treat an shml be in aceordance with me current CIA of Cmlege Station DES) Standard specification¢ for Street
G—N,[<IN, B/CS umred reChnkd Specmcatmns. Water and Sewer Ill Smarms. 2m2, and BCs umnea Deagn DAIDDE All
m ectlon snot be perf.i by ue smlf of In. CIL, Engineer of c S, .1 corAr.al. endl be [laminated colt the City at
C,S. City Enginee,
3, In Ile, of tern, Ins [aldrIctied mderids irVicvied in these plans, the Contmctor mall obtain written approval from the
City Engineer for any substitution pNar to Construction. Request¢ for changes abull inclutle product irifir—ON., IN v
where applicable. The contractor shall ba financially responsible for the engineers lime spent rev�ewrng ch,ngNA
one n.eaeighe, S.A. an [..fracture rdaue¢e,
4. Trench Safety Bepuremenle .hill be in occordonce with OSH A. Spatial 29 CFR Part USES Subpart P and of RAN ... 1,
smte and Ivmi swguldorn.
5. TRENCHING AND BAC%FILLING'. .1 Lrench'ng and bockflfng anon Canaan 10 IN. spec Pcvt'ons set Out .ere n, Tesfng shall
be proceed by I PROUNT laboratory, al the Owners eepener. Is -ril, Reae standards. Any reteshn9 By. 1. vubslandartl
.Its shelf be of led A,AO,A If the Cartoon, A-stuml are vs snail .dude all row.11A and shall IMARd or beyond the
curb Ine¢ of vl street¢ Blindd parking s 6. N 's ill respon¢E ly f the contract., to —ply with OR Some and Fee l Pegulat'an¢ regaN'ng cInstruction vcly Ede
energized r I eed overhead powenes. Additionally, poiy, the contractor shall [o.II proposed work vad procedures VAL the City
or C s. Eadmcd omiemn.
z All materids A do net identified as a Sell Bid Item spat be considered subsidiary to the aem I. ATi it i bead.
ul mvleride and epuipmed shah be bell cum !.led and insldlea .deed amer..A need.
0. The Conirv[Rr most p ovide c nslrection staking from the inNrmRiMR provide on IM1ese plans.
9. A by c titian as I[n seeding.
10. Trenchesromny be left sore, o emlght If p opedy tormlded.
11. Abjustment of Water Motor. Vvlvse. Al Imgvtion SycRms, antl any other Public or PriMvte Uliltty, etcMe not
separate pay items. The Pn[e of the adjustment snail be subsidiary,to the c ur ion of Sewer line. Farce Met,, etc.
12. The contractor shall coordinate with 5udaenlink Communications. SEAT antl can... to adjust the 1—fire,
of aerating
Ind EE it sary.
13. The 1 for s esponsble for pohn control This at a separate pay A—
A Temporary call . will be Lentri a ire by o
15. All
l raground mo-ted memmi[al equipment street be careened from c ..red ¢a NO art m b. calla from
any Weld right—b—way o Al dsb[I vtn't lRe Of the .,.It of m A pent Tve feel above gma..
sbm g Mu 11 a Tn anbu 3ng arcnteaure and s[ae memanta if s add
ith E t B Id g and Aid y,hb g will mese the slantlartls OI Spatial, SIG Of IM Rallied D p I rd... Tle qM
hat MANEL bell. v Naaue n... rig and be fxture mall drecly ,,.at light h .rim y. .cores c. b.
untN hin at
o er that nlM1e projected c al IIgM does not c any property liner
I]. Contmdvr shall provide parking tat shiping In vccord.nce with The layout shown on ills pions.
IB. At storm s onitvry s er being Constructed will this site plan Is private.
IN All 'awe 1. a backs of Curb unless sthere,, need.
20. hempRrn gate. sre coin w r than l0D' o r 6' c to net derept Thai
21, Redmond Shopping all,
is A one buid:rig plat clear
the purpose of engage. Ivnd coping and non—residentivl arc M1ite ...I
sto dSrds-
22. Transformer shall be screened from ew of the right—Of—wey and abutting property.
To nemrmdr shot open away from me nearby colors spaces
-
SUN, PI>N NOTES
Name AT Pi . Redmond SF Center
z. ILI De "ptor, Let WE, Card 3 Redmond Te a First Imlvlment
Appers If p y: 1530 TRAM, Avenue College Smtlan T%
3. Berns, RKXL rl . 2 L.
6363 tl be FRO 50
His T—A ]]OS]
en" . M'h kM L.L.P.
OR
if D" E Core zbe
SI 9 t 0
() 3
5Model SOR BN As VXfE ARLWTECTB INC.
2ONN dry". in SDNE sm
NSBATONi Tes.. ]]057
'
111,, u:ua Iptl 1
,.,-Ed V MI t tlC Of
I. operseri Bar Der It Bridge SI B firdar—
Is
star Econ-rds MI S ry a tl 9 ,Is gm rr— 9P9a g 9p^
12 No TA is al Or LOO.
No trial of this ped If,, Nrn thef .dory per HEMP, Flood Ineorari[e
Rate Mop pool 48041,0310, Effort,, DO, May 16, NER
PANNING REW REMENS
g p.I'd., 4e Peek¢
A Rricop POHNI,'.
Per Table 2 section 4.1.2 d AS
No 51—]5 early 3 Spoce(s)
3 H.C. SPoces Pmvlaea (Incluaea 3 Van kcosible)
.1 pmeided Specs. - SI
Pvgwi Fa r l MWD Tenenl dractr , CARMI
1 Space pee 250 sF-(0640 SF i 541 SF)-3]
,AN, BRAND ITEMAR
Mlemd ".In, genre--P. w
Mlemol Is eas NoSened: 1B/ISe1905F i 4elle -S40Si
Inlemd island ores andidetl- 1341SF
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SURFACE MONA
BIKE HACK
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BIKE RACK DETAIL
NTS
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2
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NTS
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SY\II d S b9 ode / \j/\\
PARKING STALL CONCRETE PAVEMENT DETAIL
NTS (PER CEOTECH RECOMMENDATIONS)
24'Iy
Ed
I r<CnQ 12'OC EW OR
Bon IT 19' ..C.w.
6T� PSI WncrMa E.
STANDARD CONCRETE PAVEMENT DETAIL
NTS (PER GEOTECH RECOMMENDATIONS)
M4 Bars O 10' OC.E.W.
A
T1-
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S CURB NTS (PER GEOTECH RECOMMENDATIONS)
NT$
VICINITY MAP
(N.T.S.)
RESERJED TRT
REM0rvp TEAE EwsT INSTALLMENT
Card An ,
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LEGEND
-
PflOPOSEO 3'/
sodden K
ILL As CROWN us
PLANS (025R MIN)J
TRENCH GRATE DETAIL
N,S.
No ee P 9 con rea M
ALF XNd
under M1ne Ad... k. The c n pate shill
At Bus t by III. A he INAP.....I
mcoot 1'P .A, anc UeP bpi
Le edge$ of the fume.
WATER LINE
It.. Mors LIKE
GIS SERVICE LINE
LNUFARNIGING TELEPHONE
DEBAGN LINE
PAN A
rE%ISTING MPHHOLEJ
CONSTRUCT NEw CURD— \�"[
443 SF
E IBENS BANTAM _
DFAIN
MBNG WRRB i0 BE
\ \ pRAIIS NGT SPWENT
TO
BORE WITH ESRISTEEL CAS NG
PARKING SETBACK
n 171
A X
m
ED
DE
DE
ASC
rTT
24" STORM SEWED
SM SF
/ PROPOSED 5
LINTLE
LE%ISi1NC EASPARY SEWED `CONSTRUCT NEW CURB
MANROLE
] 9PID 43'
2500
CONSTRUCT
NEW CURB
REDMOND DRIVE (50' ROW)
! C }541
CB s o512'06 E
E,E
OPOSED WATERLN
/rE%BRAM.
0 .NA
WATER VPLVE '
—��FXNmIAC
RE
EXISTING 516N
_NG
WATER "I
TER IRETER
PROJECT BENCHMARK: 9 INCH IRON ROD LOCATED NIN CORNER of PLOT
I Seale:
LEGEND �� '� ���
FLOW DIRECTION
EAX DRAINAGE AREA
\ PERMEABLE COVER
\
EA3
\ 0.002ACRE5
i
REDMOND DRIVE
EA4
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PROJECT BENCHMARK: B INCH IRON ROD LOCATED NW CORNER of PLOT
LEGEND f I"°h 30 fed
`,lF== FLOW DIRECTION
PAX DRAINAGE AREA
_ PERMEABLE COVER
'\PA6�
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0.045ACRES Mw I
Q �
i
Z
REDMOND DRIVE
a �
9
� I
n
r? REDMOND SHOPPING CENTER
1530 TEXAS AVENUE
DRAINAGE ANALYSIS
January 2013
Prepared for:
BKXL PARTNERS No. 2, LTD.
6363 WooDwAy DRIVE
HOUSTON, TEXAS 77057
Submitted to
(*
"� CITYOF COLLEGE S"IATION
A' the heart of the Research Valley
By
MIIT/C�HELL
Y'1M
MORGAN
ENGINEERS & CONSTRUCTORS
511 UNIVERSITY DRIVE, SUITE 204
COLLEGE STATION, TX 77840
OFFICE (979) 260-6963
FAX(979)260-3564
CERTIFICATION
This report for the drainage design for Redmond Shopping Center was prepared under
my supervision in accordance with provisions of the Bryan/College Station Unified
Drainage Design Guidelines for the owners of the property. All licenses and permits
required by any and all state and federal regulatory agencies for the proposed drainage
improvements have been issued.
.;. ..
...................:•....
.....•..
pts►�
VERON.......:..:..........:.�
Haas
{-qvµ 14�43
Veronica J.B. Morgan, P.E., C.F.M.
Registered Professional Engineer
State of Texas No. 77689
Redmond Shopping Center
1530 Texas Avenue
Drainage Report
January2013
The project site is located on Lot 9R, Block 3, of the Redmond Terrace First Installment on the north
corner of Texas Avenue and Redmond Drive as seen on Exhibit 1. The development will consist of a
8,640 square foot building with a 541 square foot outdoor patio area and required parking lot. The
proposed site plan is illustrated in Exhibit 1.
The project site was previously used as a gas station and car wash site. When these uses were
abandoned all of the impervious cover remained on the lot. These old parking and building slabs will be
removed as part of this redevelopment project.
The following report has been prepared to illustrate the drainage design for this redevelopment and its
impact to the adjoining drainage systems. The project site currently consists of 4 drainage areas, EA1
thru EA4, all of which discharge ultimately into the Texas Avenue storm sewer system. EA3 is
approximately 0.35 acres and was the site of the old gas station. This site had no subsurface drainage
system and the drainage areas simply sheet flowed and discharged thru the old curb cut toward the
intersection of Redmond and Texas Avenue. EA4 is approximately 0.01 acres and is still part of the old
gas station site but it flows directly into the gutter line of Texas Avenue. The runoff from both of these
areas enters the inlet at the intersection of Redmond and Texas Avenue.
Drainage area EA2 and EA3 are located on the old car wash site. Although this site had several grate
inlets and a storm sewer system it did not capture storm sewer runoff from the site. Rather these grate
inlets and storm drains captured just the wash water and ran it through a grit and sand chamber then to
the sanitary sewer system. EA2 is approximately 0.60 acres and runoff from this area discharged as
sheet flow out the 2 driveways onto Redmond Drive. EA3 was also part of the car wash site and was the
grassy area between the impervious cover and the curb. It discharged directly into the gutter of
Redmond Drive. Both of these areas discharged down the gutter in Redmond Drive to the same inlet on
Texas Avenue as the runoff from Drainage Areas EA1 and EA2.
Pre -development drainage areas are provided in Exhibit 2 and their corresponding flows can be found in
Table 1.
Redmond Shopping Center Page 1
Table 1- Pre -Development Peak Discharges
Q a
V
a
Q
J
N W
W
IY
u
N
o
a
n
o
0
MO
0
Q
H
N
o
C!
C7
C'1
Z
1-
Q
p
7
a
~
NO.
AC.
0.40 0.7
0.95
min
In/Hr
cfs
In/Hr
cfs
In/Hr
cfs
In/Hr
cfs
In/Hr
cfs
DA-E-01
0.35
0.02 0.00
0.33
0.32
10.0
6.33
2.0
8.6
2.7
9.9
3.1
11.1
3.5
12.5
4.0
DA-E-02
0.60
0.04 0.00
0.56
0.55
10.0
6.33
3.5
8.6
4.8
9.9
5.4
11.1
6.1
12.5
6.9
DA-E-03
0.00
0.00 0.00
0.00
0.00
10.0
6.33
0.0
8.6
0.0
9.9
0.0
11.1
0.0
12.5
0.0
DA-E-04
0.01
0.00 0.00
0.01
0.01
10.0
6.33
0.1
8.6
0.1
9.9
0.1
11.1
0.1
12.5
0.1
The post development design of the site will include several on -site storm sewer systems. Roof drains
will be captured subsurface in a storm sewer system as well as parking lot runoff. As seen in Exhibit 1
the onsite storm sewer systems will discharge into the back of 2 storm inlets on Texas Avenue.
The post development drainage design consists of 9 drainage areas, which can be seen in Exhibit 3. PA1-
3 consists of the roof areas of the building. These are captured in a roof drain system at the rear of the
building. Drainage area PA4 is the front parking lot which drains toward the intersection of Redmond
Drive and Texas Avenue where it is picked up in a 5 foot inlet and piped to the back of the storm inlet on
Texas Avenue. Drainage area PA5 is the rear parking lot and it discharges out the Redmond Drive
driveway in a similar fashion to the old car wash site. Drainage areas PA 6, 7 and 8 are all
grassy/sidewalk areas outside the developed area of the Redmond Shopping Center. Drainage areas
PA6 & 7 discharge directly to the gutter of Redmond Drive while PA8 discharges directly to the Texas
Avenue gutter. PA 9 encompasses the drainage area next to the outdoor patio as well as a portion of
the outdoor patio. This area drains to a grate inlet adjacent to the outdoor patio which then drains
subsurface to the back of a storm inlet on Texas Avenue. Post -development peak discharges are
provided in Table 2 below.
Redmond Shopping Center Page 2
Table 2 - Post -Development Peak Discharges
Q
z w
a
W
Q
O
2
J
~
N
O
of
N
O
$
o
Q
Q
0
N W
W
F
fW/1
N
C7
_
`
cy
N
0
�'
C7
=
C)
Q
Z
H
Q W
a
O
=
o
►-
c
NO.
AC.
0.40 0.7
0.95
min
In/Hr
cfs
In/Hr
cfs
In/Hr
cfs
In/Hr
cfs
In/Hr
cfs
DA-P-01
0.07
0.00 0.00
0.07
0.07
10.0
6.33
0.4
8.6
0.6
9.9
0.7
11.1
0.7
12.5
0.8
DA-P-02
0.06
0.00 0.00
0.06
0.06
10.0
6.33
0.4
8.6
0.5
9.9
0.6
11.1
0.7
12.5
0.8
DA-P-03
0.07
0.00 0.00
0.07
0.07
10.0
6.33
0.4
8.6
0.6
9.9
0.6
11.1
0.7
12.5
0.8
DA-P-04
0.27
0.01 0.00
0.26
0.25
10.0
6.33
1.6
8.6
2.1
9.9
2.4
11.1
2.7
12.5
3.1
DA-P-05
0.37
0.06 0.00
0.31
0.32
10.0
6.33
2.0
8.6
2.8
9.9
3.2
11.1
3.6
12.5
4.0
DA-P-06
0.02
0.00 0.00
0.02
0.01
10.0
6.33
0.1
8.6
0.1
9.9
0.1
11.1
0.2
12.5
0.2
DA-P-07
0.05
0.00 0.00
0.05
0.04
10.0
6.33
0.3
8.6
0.4
9.9
0.4
11.1
0.5
12.5
0.5
DA-P-08
0.04
0.00 0.00
0.04
0.04
10.0
6.33
0.2
8.6
0.3
9.9
0.4
11.1
0.4
12.5
0.5
DA-P-09
0.02
0.01 0.00
0.01
0.01
10.0
6.33
0.1
8.6
0.1
9.9
0.1
11.1
0.1
12.5
0.2
As seen in the pre vs post discharge values shown above as well as the drainage area maps it can be
illustrated that the post development runoff is less than the pre developed runoff from the site. This is
due to the existing concrete on the site and the new site additional landscape areas. The total pre
developed runoff from the site in the 100-year storm event is 11 cfs while the post developed runoff
from that same storm event is 10.9 cfs.
On site there are two storm sewer systems which will capture the onsite drainage and discharge it into
the back of 2 storm inlets on Texas Avenue. The first storm drain line is next to the outdoor patio on th
north end of the site. That system captures runoff from DA-P9, which has minimal runoff but it was not
desirable to let this run over the outdoor patio area.
Table 3 -10 Year Pipe Capacity Calculations
U
z
W
C40Qn
a
s.
v
o
r.
W
a
F
W
E
04
�.
zE.
ea
>
A
w
w
#
#
Ac.
min
yr
#
cfs
%
%
in.
fps
cfs
ft.
min
min
DA-P-01
DA-P-02
0.07
10.0
10
1
0.7
0.04
1.000
12
4.5
3.6
33
0.12
10.12
DA-P-02
DA-P-03
0.13
10.1
10
1
1.4
0.14
1.000
12
4.5
3.6
33
0.12
10.24
DA-P-03
J1
0.19
10.2
10
1
2.1
0.33
1.000
12
4.5
3.6
23
0.08
10.33
Existing
DA-P-04
SW
0.44
10.8
10
1
4.6
0.50
1.000
15
5.3
6.5
29
0.09
10.91
Existing
DA-P-09
N
0.01
10.0
10
1
0.1
0.01
1.000
8
3.5
1.2
99
0.48
10.48
J1
DA-P-04
0.19
10.3
0
1 1
1 3.0
1 0.69 1
1.000
12
4.5
3.6
134
0.49
10.82
Redmond Shopping Center Page 3
As seen in Table 3 this area required an 8 inch pipe at a minimum 1% slope to discharge the 10 year
storm event. Table 4 shows that this same 8 inch pipe can accommodate the 100-year storm event as
well.
The other drainage areas which are carried subsurface are DA-1301 thru DA-PO4. These areas are all
carried in a 12 inch pipe run at a minimum 1% slope to the 5 foot storm inlet within the parking lot. This
5 foot inlet then picks up DA-1304 and discharges it along with the upper drainage areas thru a 15 inch
pipe at a minimum 1% slope to the back of the existing storm inlet on Texas Avenue. Tables 3 & 4
illustrate the pipe capacities for this storm sewer system.
Table 4 -100 Year Pipe Capacity Calculations
44
A
W
w
#
#
Ac.
min
yr
#
cfs
%
%
in.
fps
cfs
ft.
min
min
DA-P-01
DA-P-02
0.07
10.0
100
1
1.0
0.08
1.000
12
4.5
3.6
33
0.12
10.12
DA-P-02
DA-P-03
0.13
10.1
100
1
2.0
0.30
1.000
12
4.5
3.6
33
0.12
10.24
DA-P-03
11
0.19
10.2
100
1
3.0
0.69
1.000
12
4.5
3.6
23
0.08
10.33
Existing
DA-P-04
SW
0.44
10.8
100
1
6.6
1.05
1.000
15
5.3
6.5
29
0.09
10.91
Existing
DA-P-09
NW
0.01
10.0
100
1
0.2
0.03
1.000
8
3.5
1.2
99
0.48
10.48
J1
DA-P-04
0.19
10.3
0
1
3.0
0.69
1. 000
12
4.5
3.6
1 134
1 0.49
10.82
Tables 5 & 6 illustrate the sizing of the 5 foot inlet within the parking lot. Both of these storm
events only require a 5 foot inlet to pick up the runoff from DA-PO4.
Table 5 -10-Year Inlet Capacity Calculations
SUMP CURB
(10 Year
Storm)
DA-P-04
Q =
2.13
cfs
clog =
10%
Q clogged =
2.34
cfs
=
0.83
ft
L=
1.03
ft
Redmond Shopping Center Page 4
Table 6-100-Year Inlet Capacity Calculations
SUMP CURB
100 Year Storm
DA-P-04
Q =
3.08
cfs
clog =
10%
Q clogged =
3.39
cfs
=
0.83
ft
L=
1.50
ft
Table 7 — 300-Year Grate Inlet Capacity Calculations
DA-P-09
Q =
0.17 cfs
clog =
25%
Q clogged =
0.21 cfs
Inlet Selected=
NDS#771 NDS
Open Area
Selected= 0.09 ftz
T/G= 299.03 ft
h = 0.21 ft
As seen in Table 7 above, an NDS model #771 grate inlet will handle the 100-year event with minimal
ponded depth (0.21 feet).
Conclusion
As seen in the discussion above, the post developed runoff from the Redmond Shopping Center is less
than pre development runoff rates. All post developed runoff is entering the same storm sewer system
as the predeveloped conditions and all site drainage systems have been designed for the 10 and 100-
year storm events in accordance with the BCS Unified Stormwater Design Guidelines.
Redmond Shopping Center Page 5
Attachments
EXHIBIT 1: Proposed Overall Site Plan
EXHIBIT2: Pre Development Drainage Areas
EXHIBIT 3: Post Development Drainage Areas
Redmond Shopping Center Page 6
PRD ELT
GENERLL CONSTRUCTION! NOTES
1 bNU' .1 IM1 C r IF ( III
.vat oMINN,1 ALL ee a aerymuna ul lifir ,
Cu a ablarralb, M."-V P Y P .^lobes a mnlmam o1 48 hours n v.aFF. o1 any
t',
1 HIM by 60D 3 9 63])
L t Mke Larenaer o SUIIBUFFI Gafi ]P3B
C t t NAhEDe Wo ece AtV 62 J52
e. a nma eamr WI e a Cob c(u (% I i I)6-6255
I .)F le>SIBBO
1. C lacl '.NI F.D., ey AIRIC G (May) )54-35]D
1. Al DAyelrvamn 11.11 be in a¢¢o.mn¢t w:m me bait" my of CDueva sm.a (C. S.) Slvna U.e Spear¢ulmre I, $Yem
ea tech nicol 5-H.O.C.1y Wale, ono Sewer o N Cenera6 2012 antl BCS U tl Deli n DIFFIC , NI
Co 'et- b l be Uoltl p �e 9
pe r(aemetl by the sla!( of Ne Gly Englvar el L$. All ronxlrvdian Fall be vaoNRnv teC wltM1 IM1e C91y of
3. Ir I.A.f axing e. con xlry Fri. motCUI FFR.,tetl In Ines¢ p s. the Cvntrpclol Army ablain FI.HrU vpp are from No
Fit, IF Engineer Tor vny saFF. ., Fri., b Cans, Fa ion, RelI..... la Fenger xhvr t !-'.IN pro¢utU ,laPart none U
it w1ere a.. F. k, ry en cb nag be .nanciolly responsible far the ceng�neeiz lima Part repaving ncF vngex
bay tl 9 9 n mitt, avn requests. n
r Al ly R h II be 1, itaoId-beyM1 OS, A, football 29 LFR Pah 1926 SubpoM1 P antl all Ideal,
1,,deN F C, h r M1 11 f ! lM1 i MY onx arto, OR ne . THIN,
Bee 1 y Mf' b ry t lh 0 . 1 ly IM1 1 My retexl It eoe N. b t A re
ov h II b 1 tM1 r l C I 1 St 1 are ox x. tl II a s Ina shvll exle ntl 5 6 ye L Fly
A T y p q ea
6 1 p at to, 1 lM1 RIC R r q g g 1 t
q a tl p la— Mel' IIY 111 1 1 a k a tl 'N tF 1Y
of, EI t" o"
f 5 I R'tl R h II b y itused
N tM1E blhl tl tl l IlB- all al
9. 1h I l l p q 1 f t L lh pl
, pv l h II 11 1 16 k tl' g.
I0. i II " nl M ba
11. d Wt t 9 9yl I I.W.P' I t'\ 1,
eeP to p y r area1 In a' I ..It Beb S < tryI cto s e E Men a<c
12, 1 I M1 n C 1 T s ee c (. CS wn 1. 'uxl me baron v1 exsl e9
is rt 'r
rryp a for tea X'c —FRO-FROLL TFz 's not o P 1 bay I"
e, rerr,. , yloae area will be W nrile by e
I5. AD ro ne greona— ...Red IIegvipment shall be tereirred from KIM, or abtetl z sole from
IF, pudic right —of—, v esieenlial Iislriel within Dor If the z ealteel a e grvee,
9 broil be real with lF tling o an if kd tv
en fanppev
ya.— tlor Bat py a anCmg w ao ras Df eSectlan l.fO ovlmtM1e Unified Oevtlapmenl D The RgFt
nvl pr0]ed b vq ue Fvul antl nIN IMUte s Hearty pm]¢ct Ilght F......lolly. 11o"es will be
pal
half a aI, PreN1y line
e pa Ming ID ping I� AID,thecA , fleas.
is.1 ab�N rre a:,I 111 a1 e ¢� -1 b+arUFke with mle>ile man s prvwa�
f9. NI tllmenzimz are to tF¢ ack el curb vnlexx Dtne rvixe notes.
SRE = NOTE,or Pfrect Real Sh,pping by
0 L Be- emn - aee Forme fret nnallReet
J B 2 Lad
' a se..
p.
511 U l Fire III. Sle 1OR
C 5 ros FLUID
( 9) ter 596J
5 : OD.I.Rk BANDD nNCHT11T1 AD
,IF, HE
-526
HD
IF SAMBARMHPI, C 1 C IN OrEnanaez
D w t D 9P M- ,H. P
y R Peak re 9pm
MUFF n If u'z Rare per FEMAe Flood Inmrann
Rte Map pan. ma.aml.. "bro .I I.,." bay R, .11 as
PA¢%I ED E E a
P Tbe ] 'KINtio, 4 1] A FA5
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3 NO. 5 JW (1 Ree ] 1, Access de)
T I P ed apooee = 51
Real requred: I Spee per 0. aF=(B64B aF i
541 SF)•3>
aUEFMA K WxT
L az
BIKE RACK DETAIL
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"U" FLUME DETAIL
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in) /08 ® 5"OC I, e
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ROBIDE NEPr SAWCUi
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VICINITY MAP
(N.T.S.)
IENDFNAD YRA N 1
REMOxO TERRACE PRS! INSTALLMENT 1
N/E III D65q% ]FINS. LLD /I At ] E EEM
B Ensk
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ATEfl ME2R
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T.979.260.6963
F.979,260.3564
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EXHIBIT 1
PROJECT BENCHMARK: B INCH IRON ROD LOCATED NW CORNER of PLOT
LEGEND
FLOW DIRCTION
FAX DRAINAGE AREA
\ ® PERMIABLE COVER
/ \ /-1 J 0.002ACRES
i
\
1 inch l30 fed ,
/ I/
REDMOND DRIVE
I
EA4
0,009ACRES
m
C
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F.979.260.3564
K. FIRM / F-1443
it lewosrc plea! rA>n
NNIe 3a1
auo[ tnAtton iK nee
NONE
PROJECT BENCHMARK:I INCH IRON ROD LOCATED NW CORNER of PLOT
� I I
1
iI
III
I II
III
JI
I
1
9 PVC — 9-
g-PVC T
LEGEND t inoh 30 f"tn
FLOW DIRCTION
PAX DRAINAGE AREA
® PERMIABLE COVER
I
•� ,
.LANE ---
I_
PA5
0¢.267ACRE_S
_I A
0.018ACRES
PA1
0.096ACRES PA8
0.041ACRES
4 I
PA4
PA2 0.267ACRES
0.063ACRES .�
b n
rm
PA3
0.069ACRES
11-PvC.
'4I
0.045ACRES
REDMOND DRIVE
a
I
F.978.260.3564
X FIRM / F-1443
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