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T-5 Extended Detention Basin (EDB)
Designer:
Company:
Date:
Project:
Location:
Design Procedure Form: Extended Detention Basin (EDB)
H. Dauel
BMP, Inc.
November 29, 2010
Subdivison D
NE Corner of 34th Ave. and 83rd St.
Sheet 2 of 4
5. Forebay
A) Minimum Forebay Volume V FMIN = 0.013 ac-ft
(V FMIN = 3% of the WQCV)
B) Actual Forebay Volume V F = 0.015 ac-ft
C) Forebay Depth D F = 12.0 in
(D F = 18 inch maximum)
D) Forebay Discharge
i) Undetained 100-year Peak Discharge Q 100 = 50.00 cfs
ii) Forebay Discharge Design Flow Q F = 1.00 cfs
(Q F = 0.02 * Q 100 )
E) Forebay Discharge Design
Choose One
Berm With Pipe
Wall with Rect. Notch
Wall with V-Notch Weir
(flow too small for berm w/ pipe)
F) Discharge Pipe Size (minimum 8-inches) Calculated D P = in
G) Rectangular Notch Width Calculated W N = 6.0 in
6. Trickle Channel
A) Type of Trickle Channel
Choose One
Concrete
Soft Bottom
F) Slope of Trickle Channel S = 0.0100 ft / ft
7. Micropool and Outlet Structure
A) Depth of Micropool (2.5-feet minimum) D M = 2.5 ft
B) Surface Area of Micropool (10 ft 2 minimum) A M = 125 sq ft
C) Outlet Type
Choose One
Orifice Plate
Other (Describe):
D) Depth of Design Volume (EURV or 1.2 WQCV) Based on the Design H = 2.30 feet
Concept Chosen Under 1.E.
E) Volume to Drain Over Prescribed Time EURV = 1.277 ac-ft
F) Drain Time T D = 72 hours
(Min T D for WQCV= 40 hours; Max T D for EURV= 72 hours)
G) Recommended Maximum Outlet Area per Row, (A o ) A o = 1.3 square inches
H) Orifice Dimensions:
i) Circular Orifice Diameter or D orifice = 1 - 5 / 16 inch inches
ii) Width of 2" High Rectangular Orifice W orifice = inches
I) Number of Columns n c = 1 number
J) Actual Design Outlet Area per Row (A o ) A o = 1.4 square inches
K) Number of Rows (nr) n r = 6 number
L) Total Outlet Area (A ot ) A ot = 9.3 square inches
M) Depth of WQCV (H WQCV ) H WQCV = 0.8 feet
(Estimate using actual stage-area-volume relationship and V WQCV )
N) Ensure Minimum 40 Hour Drain Time for WQCV T D WQCV = 49.7 hours
EDB-14 Urban Drainage and Flood Control District December 2010
Urban Storm Drainage Criteria Manual Volume 3