City of Frisco Engineering Standards

Engineering Standards
STORAGE = INFLOW - OUTFLOW = 34,804 cf
20 minute storm
INFLOW = 20(61.96)60 sec/min = 74,354 cf
OUTFLOW = (0.5)30(20.64)60 sec/min = 18,588 cf
STORAGE = INFLOW - OUTFLOW = 55,765 cf
30 minute storm
INFLOW = 30(51.65)60 sec/min = 92,975 cf
OUTFLOW = (0.5)40(20.64)60 sec/min = 24,785 cf
STORAGE = INFLOW - OUTFLOW = 68,190 cf
40 minute storm
INFLOW = 40(44.59)60 sec/min = 107,006 cf
OUTFLOW = (0.5)50(20.64)60 sec/min = 30,981 cf
STORAGE = INFLOW - OUTFLOW = 76,026 cf
50 minute storm
INFLOW = 50(39.41)60 sec/min = 118,219 cf
OUTFLOW = (0.5)60(20.64)60 sec/min = 37,177 cf
STORAGE = INFLOW - OUTFLOW = 81,042 cf
60 minute storm
INFLOW = 60(35.43)60 sec/min = 127,541 cf
OUTFLOW = (0.5)70(20.64)60 sec/min = 43,373 cf
STORAGE = INFLOW - OUTFLOW = 84,168 cf
70 minute storm
INFLOW = 70(32.27)60 sec/min = 135,516 cf
OUTFLOW = (0.5)80(20.64)60 sec/min = 49,569 cf
STORAGE = INFLOW - OUTFLOW = 85,947 cf
80 minute storm
INFLOW = 80(29.68)60 sec/min = 142,485 cf
OUTFLOW = (0.5)90(20.64)60 sec/min = 55,765 cf
STORAGE = INFLOW - OUTFLOW = 86,720 cf
90 minute storm
INFLOW = 90(27.53)60 sec/min = 148,679 cf
OUTFLOW = (0.5)100 (20.64)60 sec/min = 61,961 cf
STORAGE = INFLOW - OUTFLOW = 86,717 cf
Required detention storage is 86,720 cf at the 80 minute storm duration.
Section 4 – Drainage Design Requirements May 2012 Page 4-41