HomeMy WebLinkAboutWPO201900052 Calculations 2020-02-18 (5)Water Quality Peak Flow Computations
Hydrodynamic Separator
Project Name: Berkmar Drive Apartments
Timmons Group Project No. 42297
Date: 01 /20/2020
Calculated By: Cameron Morgan
Drainage Area Conditions
Water Quality Rainfall Depth, P 1.00 in
Total Area, A 7.25 acres
Impervious Area 5.00 acres
Percent Impervious 69.0 %
Treatment Volume (per VRRM), Tv 21,215 cf
Curve Number (CN) 98
Time of Concentration, Tc 10 min
Unit Conversions
Area, Am (mi) 0.0113 mil
Tc (hours) 0.17 hours
Derived Values
Runoff Volume, Qa 0.81 in
Potential Maximum Retention, S 0.25 in
Initial Abstraction, la 0.05 in
la/P 0.05
Use 0.10
Unit Peak Discharge, q„
(ref. Exhibit 4-II of the TR55 Manual; see next page)
qU = 850 csm/in
Water Quality Storm Peak Flow, Q,,(,
QWQ = 7.76 ds
TIMMONS GROUP
YOUR VISION ACHIEVED THROUGH OURS.
Hydrologic Equations
S=1CN T —10 Qa=A
Ia = 0.2S QwQ = q.A.Qa
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Water Quality Peak Flow Computations
Hydrodynamic Separator
Project Name: Berkmar Drive Apartments
Timmons Group Project No. 42297
Date: 01 /20/2020
Calculated By: Cameron Morgan
400
TIMMONS GROUP
YOUR VISION ACHIEVED THROUGH OURS.
Hxhib3t 4-II Urat peal dl%charge (cIJ for NRCS (SM type II rainfall di-9mbutlan
800
600
500
2 400 70
.Pp
LP
D
20❑
a
C
100
80
60
so
1 .2 .4 .6 .6 1 2 4 6 a i n
Time at concentration (T.),;hnuro
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