Item 6B - Drainage PlansHAMILTON DUFFY, P.C.
Civil & Environmental Engineers · Planners · Construction Managers
Texas Firm Reg. No. F-5260
____________________________________________________
8241 Mid-Cities Blvd., #100 North Richland Hills, TX 76182
(817) 268-0408 www.hamiltonduffy.com
July 17, 2026
City of Southlake
Public Works Department
RE: Drainage Concept for Bridlegate Subdivision
4000 North White Chapel Blvd. (9.562 Acres, 8 lots)
Southlake, Texas
We are pleased to present you this explanation of our preliminary drainage concept design for
Bridlegate Subdivision. We have prepared some color renderings showing where the pre-
developed storm water runoff travels and where the post-developed runoff travels. Below is a
detailed narrative explanation of our drainage drawings:
C1.10 (Pre-Developed Drainage Area Map) – This map shows pre-developed drainage
conditions. Areas labeled with an O are offsite areas to our west draining onto and through our
property. Areas O1+A1 (RED) drain north to a grate inlet in West Bob Jones Road and through
Saddleback Ridge Estates. Areas O2+B1 (GREEN) drain east to a concrete flume in Rainey
Court Subdivison. Areas O3+C1 (PURPLE) drain east to N. White Chapel Blvd. bar ditch. Area
D1 (BLUE) drains east into the backyards of Lots 1 and 2 of Rainey Court. Area E1
(YELLOW) drains east down West Bob Jones Road bar ditch.
C1.11 (Post-Developed Drainage Area Map) – This map shows proposed post-developed
drainage conditions. Notice how the color codes match the Pre-Developed Map and how
consistent in size and direction the drainage areas are maintained. Areas O1+A1 (RED) continue
to go to the existing Bob Jones Road grate inlet. Pre-Developed flow rates are maintained so
there is no need for a detention pond. Areas 02+B’s (GREEN) are ultimately directed to
proposed Detention Pond B. This pond has been preliminarily sized such that pre-developed
flow rates are maintained and discharged directly to the existing concrete flume in Rainey Court.
Areas 03+C’s (PURPLE) are ultimately directed to proposed Detention Pond C. This pond has
been preliminarily sized such that pre-developed flow rates are maintained and discharged to the
N. White Chapel Blvd. bar ditch. Area D1 (BLUE) has been minimized and less than pre-
developed flow rates drain east into the backyards of Lots 1 and 2 of Rainey Court. Area E1
(YELLOW) drains east down West Bob Jones Road bar ditch at pre-developed flow rates.
C1.12 (Drainage Calculations) – This drawing shows Post-Developed flow rates for areas
depicted on Sheet C1.11. The drawing also shows the preliminary sizing of the detention ponds.
We have left more than enough available area for the future design and construction of the
detention ponds.
Drainage Concept for Bridlegate Page 2 of 2
4000 N. White Chapel (9.562 Ac) – Southlake, Texas July 17, 2026
We have attached mentioned Drainage Area Maps to this letter. We are available to discuss this
project at any time.
Sincerely,
HAMILTON DUFFY, P.C.
Keith Hamilton
Keith Hamilton, P.E.
Attachments
0
SCALE 1" = 60'
30 60 120
C1.10 PRE-DEVELOPED DRAINAGE AREA MAPPDRAINAGE AREA COMPUTATIONS
Q = CIA (Rational Method)
Q = Storm discharge (cubic feet per second)
C = runoff coefficient, based on land use
A = area contributing runoff (acres)
BASIS:
RUNOFF COEFFICIENT:
ground to the storm drain inlet (onsite + offsite, if applicable)
being the time for water to flow over the surface of the
Combination of inlet time and time of flow in the drain
STORM FREQUENCY:
TIME OF CONCENTRATION:
MINIMUM INLET TIME OF CONCENTRATION:
100 Years - Combined Enclosed Pipe System + Street + R.O.W.
5 Years - Enclosed Pipe System
Commercial, Business
Residential, Single Family
Parkland, Undeveloped Land
10 minutes
15 minutes
20 minutes
OS1 DRAINAGE AREA
DRAINAGE DIVIDE
FLOW DIRECTION ARROW
LEGEND
(inches per hour) (per ISWM)
I = average rainfall intensity for time of concentration
MARK AREA
(AC)
C Tc
(MIN.)
QI
(IN/HR)
COMMENTS
(CFS)
100I
(IN/HR)
10 Q
(CFS)
10100
0.350.52 1.51.0A1
0.35 154.19 11.85.34 8.02O1
I
(IN/HR)
10
3.23
Q
(CFS)
1
0.6
4.7
PRE-DEVELOPED SITE DRAINAGE DATA
O1
O2
O3
A1
B1
E1
D1
C1
C = 0.95 Paved Areas/Roofs
C = 0.45 Single Family (1+ acre lots)
C = 0.35 Partially Developed Areas
C = 0.30 Unimproved Areas
20 4.52 6.762.73
15 5.34 8.023.23
0.352.45 6.94.6B1
0.35 151.68 3.95.34 8.02 2.6O23.23
2.8
1.6
15 5.34 8.023.23
TO 3' GRATE INLET
Q100 (DESIGN) = 12.9 CFS
RIDGE ESTATES (2016)
FROM PLANS FOR SADDLEBACK
Q100 DESIGN = 2 CFS
COURT (2024)
FROM PLANS FOR RAINEY
Q100 DESIGN = 8 CFS
COURT (2024)
FROM PLANS FOR RAINEY
0.354.13 9.86.53.9
TO 3' GRATE INLET
TO 3' GRATE INLET
TO B1
TO RAINEY COURT
0.356.09 17.111.4C1
0.35 151.01 2.85.34 8.02 1.9O33.23
6.9
1.1
15 5.34 8.023.23
TO C1
0.350.63 1.81.2D1
0.35 150.28 0.85.34 8.02 0.5E13.23
0.8
0.3
15 5.34 8.023.23 TO RAINEY COURT
O2+B1
20 4.52 6.762.730.357.10 16.811.26.8O3+C1
TO N. WHITE CHAPEL
TOTAL TO N. WHITE CHAPEL
TO BOB JONES RD.
7.8
RAINEY CT SHOW Q100 = 8 CFS)
TOTAL TO RAINEY COURT (PLANS FOR
Q100 PRE = 16.8 CFS
BAR DITCH
N WHITE CHAPEL
DISCHARGES TO
JOBDATECHECKEDBYDATENO.SHEETREVISION DRAWNDESIGNED K.M.H.999-640K.M.H.K.M.H.C O N S U L T I N GNUMBER F-5260ENGINEERING FIRMTEXAS REGISTERED CIVIL & ENVIRONMENTAL ENGINEERS - PLANNERS - CONSTRUCTION MANAGERS8241 MID-CITIES BLVD., SUITE 100 - NORTH RICHLAND HILLS, TEXAS 76182 PHONE (817) 268-0408 www.hamiltonduffy.com4-27-26
DATEBRIDLEGATECITY CASE NO: ZA26-0040 CITY OF SOUTHLAKE, DENTON COUNTY, TEXASDOCUMENT NUMBER 2015-340 P.R.D.C.T.LOT 2R, R.D. PRICE NO. 992-ADDITION1REVISED PER CITY CONCEPT REVIEWKMH5-6-26578 ft
579 ft
580 ft
580 ft
581 ft
581 ft
581 ft
581 ft
581 ft
581 ft
582 ft
582 ft
582 ft
582 ft
582 ft
582 ft
583 ft
583 ft
583 ft
583 ft
583 ft
583 ft
583 ft
583 ft
584 ft
584 ft
584 ft
584 ft
584 ft
585 ft
585 ft
587 ft
587 ft
588 ft
588 ft
588 ft
588 ft
590 ft
590 ft
591 ft
595 ft
595 ft
600 ft
600 ft
600 ft
602 ft
603 ft
604 ft
605 ft
605 ft
606 ft
607 ft
609 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
611 ft
612 ft
612 ft
612 ft
613 ft
613 ft
615 ft
616 ft
617 ft
618 ft
620 ft
621 ft
624 ft
625 ft
626 ft
627 ft
628 ft
630 ft
631 ft
632 ft
634 ft
635 ft
636 ft
637 ft
642 ft
643 ft
644 ft
645 ft
645 ft
646 ft
647 ft
648 ft
649 ft
650 ft
651 ft
652 ft
653 ft
654 ft
654 ft
655 ft
656 ft
657 ft
658 ft
658 ft
659 ft
660 ft
661 ft
662 ft
662 ft
663 ft
664 ft
665 ft
666 ft
667 ft
667 ft
667 ft
667 ft
667 ft
S SEWER MANHOLE
FL RCP 18"
POWER POLE
POWER POLE
DELIVERY BOX
FL RCP 18
TPED
TELEPHONE PEDESTAL
FL RCP 18"
UNDERGOUND TELEPHONE SIGN
FL RCP 18"
POWER POLE
POWER POLE
GAS SIGN
S
SEWER MANHOLE
MB
KEYPAD
GATE MOTOR
GATE MOTOR
POWER POLE
GUY WIRE
EM
ELECTRIC METER
FL PVC 6"
FL PVC 6"
GM
GAS METER
POWER POLEPOWER POLE
TPED
TELEPHONE PEDESTAL
MH
UNKNOWN MANHOLE (MFDSD)
POWER POLE
TELEPHONE SIGN ABOVE NET
COVERED PUMP
COVERED PUMP
EB
ELECTRIC BOX
WM
WATER METER
UTILITY BOX
SEPTIC LID
WM
WATER METER
POWER POLE
POWER POLEGUY WIRE
MP
MP
MP
MP
MP
MP
MP
MP
MP MP MP
MP
MP
MP
MP
MP
MP
MP MP
MP
MP
MP
MP
MP MP
MP
MP
MP
MP
MP MP
MP MP
MPMP
MP RAINEY COURT(50' R.O.W.)W. BOB JONES ROAD
(60' R.O.W.)N. WHITE CHAPEL BLVD(R.O.W. VARIES)CAB. V, PG. 822 P.R.D.C.T.R.D. PRICE NO. 992 ADDITIONLOT 4PG. 121 D.R.D.C.T.)
(DESCRIPTION VOL. 1221,
DOC. NO. 2013-41309 D.R.D.C.T.
MARIE W. GRIBSBY
1.000 ACRES
LOT 19
CAB. U, PG. 19, P.R.D.C.T.
BLOCK 1, CLARIDEN RANCH, PHASE II
LOT 18LOT 17LOT 16LOT 15LOT 14LOT 13LOT 12
CAB. N, PG. 48 P.R.D.C.T.
LOT 2, BLOCK 1, REEDER ADDITION
4913 SQ. FT.
AREA IN QUESTION
P.R.D.C.T.DOCUMENT NUMBER 2015-340LOT 2R, R.D. PRICE NO. 992 ADDITION ACRES9.562
40' BUILDING LINE
40' BUILDING LINE40' BUILDING LINE20' BUILDING LINE20' BUILDING LINE
20' BUILDING LINE
CAB. V, PG. 822 P.R.D.C.T.
R.D. PRICE NO. 992 ADDITION
LOT 4
1/2" IRF, SOUTHEAST CORNER OF LOT 4
5.595 ACRE TRACT
IN THE SOUTH LINE OF
TRACT 11-1.83 ACRES
1/2" IRF (C.M.), SOUTHEAST CORNER OF
5.20'
270.06'
DOCUMENT NUMBER 2017-459, P.R.D.C.T.
SADDLEBACK RIDGE ESTATES
LOT 1, BLOCK 1
WEST BOB JONES ROAD
(60' R.O.W.)SADDLEBACK LANEDOCUMENT NUMBER 2017-459, P.R.D.C.T.(LOT 43, BLOCK 1 - PRIVATE STREET)DOCUMENT NUMBER 2017-459, P.R.D.C.T.
SADDLEBACK RIDGE ESTATES
LOT 34, BLOCK 1
2024-120, P.R.D.C.T.
DOCUMENT NUMBER
RAINEY COURT
LOT 1
2024-120, P.R.D.C.T.
DOCUMENT NUMBER
RAINEY COURT
LOT 2
2024-120, P.R.D.C.T.
DOCUMENT NUMBER
RAINEY COURT
LOT 3
2024-120, P.R.D.C.T.
DOCUMENT NUMBER
RAINEY COURT
LOT 4
"X" CUT FOUND
"X" CUT FOUND
1/2" IRF RED CAP "PEISER & MANKIN"
"X" CUT FOUND
1/2" IRF WITH RED CAP
STAMPED "PRISM SURVEYING"
3/8" IRF
1/2" IRF WITH YELLOW CAP
STAMPED "GOODWIN & MARSHALL"
1/2" IRF WITH ORANGE CAP
STAMPED "SPRY RPLS 5647"
1/2" IRF RED CAP "PEISER & MANKIN"
"Y" CUT FOUND
1/2" IRF
1/2" IRF "SPRY'
1/2" IRF WITH RED CAP
STAMPED "PRISM SURVEYING"
1/2" IRF WITH RED CAP
STAMPED "PRISM SURVEYING"
1/2" IRF WITH ORANGE CAP
STAMPED "SPRY RPLS 5647"
1/2" IRF WITH YELLOW CAP
STAMPED "GOODWIN & MARSHALL"
3/8" IRF
P
O
N
D
P
O
N
D
P
O
N
D
IRRIGATION CONTROL VALVEIRRIGATION CONTROL VALVE
AREA DRAIN
AREA DRAINPOOL CLEANOUT
POOL CLEANOUTAREA DRAIN
AREA DRAIN
POOL CLEANOUT
JUMP BOARD
AC
EM ELECTRIC METER
POOL EQUIPMENT
AC
AC
AC
BASKETBALL HOOP
AREA DRAIN
FIREPLACE
FIREPLACE
GRILL & BAR
FOUNTAIN
STONE RUNNER
RUNNER
STONE
STAIRCASE TO BALCONY
0
SCALE 1" = 60'
30 60 120
C1.11
OS1 DRAINAGE AREA
DRAINAGE DIVIDE
FLOW DIRECTION ARROW
LEGEND POST-DEVELOPED DRAINAGE AREA MAPPDRAINAGE AREA COMPUTATIONS
Q = CIA (Rational Method)
Q = Storm discharge (cubic feet per second)
C = runoff coefficient, based on land use
A = area contributing runoff (acres)
BASIS:
RUNOFF COEFFICIENT:
ground to the storm drain inlet (onsite + offsite, if applicable)
being the time for water to flow over the surface of the
Combination of inlet time and time of flow in the drain
STORM FREQUENCY:
TIME OF CONCENTRATION:
MINIMUM INLET TIME OF CONCENTRATION:
100 Years - Combined Enclosed Pipe System + Street + R.O.W.
5 Years - Enclosed Pipe System
Commercial, Business
Residential, Single Family
Parkland, Undeveloped Land
10 minutes
15 minutes
20 minutes
(inches per hour) (per ISWM)
I = average rainfall intensity for time of concentration
C = 0.95 Paved Areas/Roofs
C = 0.45 Single Family (1+ acre lots)
C = 0.35 Partially Developed Areas
C = 0.30 Unimproved Areas
Q100 DESIGN = 2 CFS
COURT (2024)
FROM PLANS FOR RAINEY
TO 3' GRATE INLET
Q100 (DESIGN) = 12.9 CFS
RIDGE ESTATES (2016)
FROM PLANS FOR SADDLEBACK
O1
O2
A1
E1
D1
B1
C2
POND B
DETENTION
POND C
DETENTION
COURT (2024)
FROM PLANS FOR RAINEY
EQUAL TO 8 CFS (100 YR)
POND TO BE LESS THAN OR
RELEASE FROM DETENTION
(SEE PRE-DEVELOPED MAP)
EQUAL TO 16.8 CFS (100 YR)
POND TO BE LESS THAN OR
RELEASE FROM DETENTION
B3
B2
C1
C4
C5
O3A
O3B
C3
3' D.I.
3' D.I.
3' D.I.
3' D.I.
10' C.I.
10' C.I.
S SEWER MANHOLE
FL RCP 18"
FL RCP 18
TPED
FL RCP 18"
FL RCP 18"
POWER POLE
POWER POLE
S
SEWER MANHOLE
MB
EM
GM
GAS METER
POWER POLEPOWER POLE
TPED
TELEPHONE PEDESTAL
MH
POWER POLE
TELEPHONE SIGN ABOVE NET
WM
GUY WIRE
MP RAINEY COURT(50' R.O.W.)W. BOB JONES ROAD
(60' R.O.W.)N. WHITE CHAPEL BLVD(R.O.W. VARIES)CAB. V, PG. 822 P.R.D.C.T.R.D. PRICE NO. 992 ADDITIONLOT 4PG. 121 D.R.D.C.T.)
(DESCRIPTION VOL. 1221,
DOC. NO. 2013-41309 D.R.D.C.T.
MARIE W. GRIBSBY
1.000 ACRES
LOT 19
CAB. U, PG. 19, P.R.D.C.T.
BLOCK 1, CLARIDEN RANCH, PHASE II
LOT 18LOT 17LOT 16LOT 15LOT 14LOT 13LOT 12
CAB. N, PG. 48 P.R.D.C.T.
LOT 2, BLOCK 1, REEDER ADDITION
CAB. V, PG. 822 P.R.D.C.T.
R.D. PRICE NO. 992 ADDITION
LOT 4
1/2" IRF, SOUTHEAST CORNER OF LOT 4
5.20'
270.06'
DOCUMENT NUMBER 2017-459, P.R.D.C.T.
SADDLEBACK RIDGE ESTATES
LOT 1, BLOCK 1
WEST BOB JONES ROAD
(60' R.O.W.)SADDLEBACK LANEDOCUMENT NUMBER 2017-459, P.R.D.C.T.(LOT 43, BLOCK 1 - PRIVATE STREET)DOCUMENT NUMBER 2017-459, P.R.D.C.T.
SADDLEBACK RIDGE ESTATES
LOT 34, BLOCK 1
2024-120, P.R.D.C.T.
DOCUMENT NUMBER
RAINEY COURT
LOT 1
2024-120, P.R.D.C.T.
DOCUMENT NUMBER
RAINEY COURT
LOT 2
2024-120, P.R.D.C.T.
DOCUMENT NUMBER
RAINEY COURT
LOT 3
2024-120, P.R.D.C.T.
DOCUMENT NUMBER
RAINEY COURT
LOT 4
"X" CUT FOUND
"X" CUT FOUND
1/2" IRF RED CAP "PEISER & MANKIN"
"X" CUT FOUND
1/2" IRF WITH RED CAP
STAMPED "PRISM SURVEYING"
3/8" IRF
1/2" IRF WITH YELLOW CAP
STAMPED "GOODWIN & MARSHALL"
1/2" IRF WITH ORANGE CAP
STAMPED "SPRY RPLS 5647"
1/2" IRF RED CAP "PEISER & MANKIN"
"Y" CUT FOUND
1/2" IRF
1/2" IRF "SPRY'
1/2" IRF WITH RED CAP
STAMPED "PRISM SURVEYING"
1/2" IRF WITH RED CAP
STAMPED "PRISM SURVEYING"
1/2" IRF WITH YELLOW CAP
STAMPED "GOODWIN & MARSHALL"
3/8" IRF
1/2" IRF WITH ORANGE CAP
STAMPED "SPRY RPLS 5647"
5.595 ACRE TRACT
IN THE SOUTH LINE OF
TRACT 11-1.83 ACRES
1/2" IRF (C.M.), SOUTHEAST CORNER OF
15' D&UE
JOBDATECHECKEDBYDATENO.SHEETREVISION DRAWNDESIGNED K.M.H.999-640K.M.H.K.M.H.C O N S U L T I N GNUMBER F-5260ENGINEERING FIRMTEXAS REGISTERED CIVIL & ENVIRONMENTAL ENGINEERS - PLANNERS - CONSTRUCTION MANAGERS8241 MID-CITIES BLVD., SUITE 100 - NORTH RICHLAND HILLS, TEXAS 76182 PHONE (817) 268-0408 www.hamiltonduffy.com4-27-26
DATEBRIDLEGATECITY CASE NO: ZA26-0040 CITY OF SOUTHLAKE, DENTON COUNTY, TEXASDOCUMENT NUMBER 2015-340 P.R.D.C.T.LOT 2R, R.D. PRICE NO. 992-ADDITION1REVISED PER CITY CONCEPT REVIEWKMH5-6-26578 ft
579 ft
580 ft
580 ft
581 ft
581 ft
581 ft
581 ft
581 ft
581 ft
582 ft
582 ft
582 ft
582 ft
582 ft
582 ft
583 ft
583 ft
583 ft
583 ft
583 ft
583 ft
583 ft
584 ft
584 ft
584 ft
584 ft
584 ft
585 ft
587 ft
587 ft
588 ft
590 ft
590 ft
603 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
610 ft
618 ft
620 ft
621 ft
624 ft
625 ft
626 ft
627 ft
628 ft
630 ft
631 ft
632 ft
634 ft
635 ft
636 ft
637 ft
642 ft
643 ft
644 ft
645 ft
645 ft
646 ft
647 ft
648 ft
649 ft
650 ft
651 ft
652 ft
653 ft
654 ft
654 ft
655 ft
656 ft
657 ft
658 ft
658 ft
659 ft
660 ft
661 ft
662 ft
662 ft
663 ft
664 ft
665 ft
666 ft
667 ft
667 ft
667 ft
667 ft
667 ft
40' BL
40' BL40' BL40' BL
1
2
3
4
5
7
8
6
40' BL40' BL20' BL
20' BL
20' BL
20' BL40' BL20' BL20' BL
40' BL40' BL40' BL40' BL20' BL
20' BL
20' BL
20' BL
20' BL 20' BL 20'
BL
20'
BL
15' DE
25' SSE &
DE
20' SSE & DE15' WE40' BL DEBLBL DE
DE
DE
DE
DE
DE
DE
DE
D E
D E
3' LWE
3' LWE
40' BL
15' WE
CURB/DROP OPENING INLET IN SUMP: Q/L = 3.0Y
INLET CAPACITY CALCULATIONS
3/2
Y = (Depth of flow at Opening) (ft)
L = Length of Inlet Opening (ft)
Q = Storm Drainage Discharge (cfs)
Where:
8" Depth (ROW depth): Qcap = 16.3 cfs
6" Depth (curb depth): Qcap = 10.6 cfs
For 10' Curb Inlet in sump:
9" Depth: Qcap = 15.6 cfs
6" Depth: Qcap = 8.5 cfs
For 2' Drop Inlet:
12" Depth: Qcap = 48.0 cfs
6" Depth: Qcap = 17.0 cfs
For 4' Drop Inlet:
12" Depth: Qcap = 36.0 cfs
6" Depth: Qcap = 12.7 cfs
For 3' Drop Inlet:
8" Depth: Qcap = 9.8 cfs
6" Depth: Qcap = 6.3 cfs
(*assume 50% open due to Grate)
For 3' Grate Inlet in sump:
MARK AREA
(AC)
C Tc
(MIN.)
QI
(IN/HR)
COMMENTS
(CFS)
100I
(IN/HR)
10 Q
(CFS)
10100
0.450.33 1.20.8A1
0.35 154.19 11.85.34 8.02O1
I
(IN/HR)
10
3.23
Q
(CFS)
1
0.5
4.7
15 5.34 8.023.23
0.450.83 3.02.0B1
0.35 151.68 3.95.34 8.02 2.6O23.23
1.2
1.6
15 5.34 8.023.23
2.51 6.9
TO 3' GRATE INLET
TO B1
0.451.00 3.62.4C1
0.35 150.89 2.55.34 8.02 1.73.23
1.5
1.0
15 5.34 8.023.23
TO C1
0.450.18 0.60.4D1
0.45 150.23 0.85.34 8.02 0.6E13.23
0.3
0.3
15 5.34 8.023.23
O2+B1
1.89O3A+C1
7.8
POST-DEVELOPED SITE DRAINAGE DATA
2. WEIGHTED RUNOFF COEF. = [1.01(0.35)+6.08(0.45)]/7.09 = 0.44
1. WEIGHTED RUNOFF COEF. = [1.68(0.35)+3.14(0.45)]/4.82 = 0.42
TO BOB JONES RD. (EQUALS PRE-DEV)
TO 3' GRATE INLET
(LESS THAN PRE-DEV)
TOTAL TO 3' GRATE INLET
01+A1 13.0
TO 3' DROP INLET
TOTAL TO 3' DROP INLET
0.451.18 4.32.8B31.7155.34 8.023.23
0.451.13 4.12.7B21.6155.34 8.023.23
TO DETENTION POND B
TO 2-10' CURB INLETS
0.424.82 13.79.25.520 TOTAL TO DETENTION POND B
+B2+B3
O2+B1 1
4.52 6.762.73
O3A
TO 3' DROP INLET
TOTAL TO 3' DROP INLET6.1
0.450.68 2.51.6C2
0.35 150.12 0.35.34 8.02 0.23.23
1.0
0.1
15 5.34 8.023.23
TO C2
0.80O3B+C2
O3B
TO 3' DROP INLET
TOTAL TO 3' DROP INLET2.8
0.447.09 21.114.18.520 TOTAL TO DETENTION POND C
2
4.52 6.762.73
0.450.31 1.10.7C30.5155.34 8.023.23
0.450.97 3.52.3C41.4155.34 8.023.23 TO 3' DROP INLET
0.453.12 11.37.5C54.5155.34 8.023.23
...C5
O3A
TO 10' CURB INLET
TO DETENTION POND C
TO RAINEY COURT (LESS THAN PRE-DEV)
RUNOFF.
DOES NOT EXCEED THE PRE-DEVELOPED
POST-DEVELOPED RUNOFF LEAVING THE SITE
DETENTION POND DESIGNED SUCH THAT THE
DETENTION POND B DESIGN (100 YR)
Q100 = 13.7 CFS
TC = 20 MIN
C = 0.42
AREA = O2+1+B2+B3 = 4.82 ACRES
Q100 TO DETENTION:
Q100(ALLOWABLE) = 8 - 0 = 8 CFS
Q100(ALLOWABLE) = QPRE - QBYPASS
Q100(BYPASS) = 0 CFS
Q100(PREDEVELOPED) = 8 CFS = (SEE RAINEY CT PLANS)
RUNOFF.
DOES NOT EXCEED THE PRE-DEVELOPED
POST-DEVELOPED RUNOFF LEAVING THE SITE
DETENTION POND DESIGNED SUCH THAT THE
DETENTION POND C DESIGN (100 YR)
Q100 = 21.1 CFS
TC = 20 MIN
C = 0.44
AREA = 03A+C1+03B+C2+C3+C4+C5 = 7.09 ACRES
Q100 TO DETENTION:
Q100(ALLOWABLE) = 16.8 - 0 = 16.8 CFS
Q100(ALLOWABLE) = QPRE - QBYPASS
Q100(BYPASS) = 0 CFS
Q100(PREDEVELOPED) = 16.8 CFS = (SEE PRE-DEV MAP)
C1.12 DRAINAGE CALCULATIONSJOBDATECHECKEDBYDATENO.SHEETREVISION DRAWNDESIGNED K.M.H.999-640K.M.H.K.M.H.C O N S U L T I N GNUMBER F-5260ENGINEERING FIRMTEXAS REGISTERED CIVIL & ENVIRONMENTAL ENGINEERS - PLANNERS - CONSTRUCTION MANAGERS8241 MID-CITIES BLVD., SUITE 100 - NORTH RICHLAND HILLS, TEXAS 76182 PHONE (817) 268-0408 www.hamiltonduffy.com4-27-26
DATEBRIDLEGATECITY CASE NO: ZA26-0040 CITY OF SOUTHLAKE, DENTON COUNTY, TEXASDOCUMENT NUMBER 2015-340 P.R.D.C.T.LOT 2R, R.D. PRICE NO. 992-ADDITION1REVISED PER CITY CONCEPT REVIEWKMH5-6-26