HomeMy WebLinkAboutStormwater Report - 47 PETERS STREET 8/17/1993 Bv: GPF Date: 8/17/93 Sub.iect: First United Methodist Sheet No: 1 of 1
CHKD by RFK Date: Church b Peters St. North
Drainage Calculations
USE RATIONAL METHOD
Q = C X i X a
C = COEFFICIENT OF RUNOFF
i = RAINFALL
CRITERIA = 15 YR STORM
PROPOSED CONDITIONS
C = 0. 90 PAVED
Tc = 310 Ft - 4 Ft/Sec = 77 .5 Sec ( <5 Min. )
i15 = 6 .0
a = 0.20 AC.
GIs = 0. 90 X 6 .0 X 0.20 AC.
1 .08 cfs
VOLUME OF RUNOFF
Vol . = Tb/2 X Q, Tb = 2.67 X Tc, Tc = 77 Sec.
Vol . = 77 X 2.67 X 1 .08 Cfs
2
Vol . = 111 Cubic Ft.
Q50 = 0.90 X 7 . 2 X 0. 20 AC = 1 . 30 cf s
V0150 = 77 X 2. 67 X 1 .30
2
Vol 50 = 534 Cubic Ft.
TOTAL VOLUME OF RETENTION AREA = 5,606 CUBIC FEET
Bv: GPF Date: 8/17193 Subject: First United Methodist Sheet No: 1 of 1
CHKD by RFK Date: Church 6 Peters St. North
Drainage Calculations
USE RATIONAL METHOD
O = C X i X a
C = COEFFICIENT OF RUNOFF
i m RAINFALL
CRITERIA = 15 YR STORM
PROPOSED CONDITIONS
C = 0.90 PAVED
Tc = 310 Ft - 4 Ft/Sec = 77 .5 Sec ( <5 Min. )
i 1 = 6 .0
a = 0.20 AC.
015 = 0.90 X 6.0 X 0.20 AC.
1 .08 cfs
VOLUME OF RUNOFF
Vol . = Tb/2 X O, Tb = 2.67 X Tc, Tc = 77 Sec.
Vol . = 77 X 2. 67 X 1 .08 cfs
2
Vol . = 111 Cubic Ft.
050 = 0.90 X 7 . 2 X 0 .20 AC = 1 .30 cfs
V0150 = 77 X 2 .67 X 1 .30
2
V0150 = 534 Cubic Ft.
TOTAL VOLUME OF RETENTION AREA = 51606 CUBIC FEET
Bv: GPF Date: 8/17/93 9ub.iect: First United Methodist Sheet No: 1 of 1
CHKD by RFK Date: Church & Peters St. North
Drainage Calculations
USE RATIONAL METHOD
O = C X i X a
C = COEFFICIENT OF RUNOFF
i = RAINFALL
CRITERIA = 15 YR STORM
PROPOSED CONDITIONS
C = 0.90 PAVED
Tc = 310 Ft - 4 Ft/Sec = 77 .5 Sec ( <5 Min. )
i15 = 6 .0
a = 0.20 AC.
G15 = 0.90 X 6 .0 X 0.20 AC.
=
1 .08 cfs
VOLUME OF RUNOFF
Vol . = Tb/2 X Q, Tb = 2.67 X Tc, Tc = 77 Sec.
Vol . = 77 X 2.67 X 1 .08 cfs
2
Vol . = 111 Cubic Ft.
050 = 0. 90 X 7.2 X 0.20 AC = 1 . 30 cfs
V0150 = 77 X 2. 67 X 1 .30
2
V0150 = 534 Cubic Ft.
TOTAL VOLUME OF RETENTION AREA = 5. 606 CUBIC FEET