SW6211001_Design Calculations (Q 10-Yr, Pond 2)_20220128

DESIGN REQUIREMENTS:
A. Post development discharge < or = Predevelopment discharge
Drainage Area, (DA) _
Intensity, (I) _
Composite Runoff Coefficient, (C) _>
Maximum Release Rate, (Q10) _>
Drainage Area, (DA) _
Intensity, (I) _
Composite Runoff Coefficient, (C) _>
Peak Release Rate, (Q10) _>
3.56 acres
6.31 inches/hr
0.30
6.74 cfs
r�
6.29 acres
7.88 inches/hr
0.70
34.70 cfs
Contour
Contour
Incr.
Accum.
Stage
Elev.
Area
Storage
Storage (S)
(Z)
00
(sf)
(cf)
(cf)
00
In (S)
In (Z)
Z est
251.7
14,994
-
-
-
-
252.2
17,418
8,103
8,103
0.50
9.00
-0.69
0.55
252.7
18,659
9,019
17,122
1.00
9.75
0.00
1.04
253.2
19,919
9,645
26,767
1.50
€ 10.19 €
0.41
1.50
253.7
21,198
10,279
37,046
2.00
€ 10.52 €
0.69
1.97
254.2
22,493
10,923
47,969
2.50
10.78
0.92
2.45
254.7
23,804
11,574
59,543
3.00
€ 10.99 €
1.10
2.94
255.2
25,133
12,234
71,777
3.50
11.18
1.25
3.43
255.7
26,475
12,902
84,679
4.00
11.35
1.39
3.94
256.2
27,831
13,577
98,256
4.50
€ 11.50 €
1.50
4.46
256.7
29,202
14,258
112,514
5.00
11.63
1.61
5.00
257.2
30,587
14,947
127,461
5.50
11.76
1.70
5.55
257.7
31,985
15,643
143,104
6.00
€ 11.87 €
1.79
6.12
258.2
33,398
16,346
159,450
6.50
11.98
1.87
6.69
Regression Output:
b= 1.20 (X Variable Coeff)
Ks- 16,427 (eY-i ter-pt)
Stage - Storage Equation is of the form: S = (Ks)(Z)b
printed: 1/28/2022 3:59 PM Page 1 of 3

Barrel
Number of Barrels =
Dia. of Barrel =
Area of Barrel, (Ab) _
Pipe Length, (L) _
Friction Coeff, (Kp) _
Inv. of Barrel =
Riser
Elev. of Riser Crest
Rectangular
Length Weir— 36 inches
Total Weir Length=
Area of Riser =
Orifice in Riser
Dia. of Orifice =
Number of Orifices =
Area of Orifice, (Ab) _
Orifice Coefficient (Cd) _
Inv. of Orifice =
Length of weir —
Top of weir —
Weir Coefficient (Cw)—
Width of Spillway (Approx.) _
Weir Coefficient =
Crest Elevation =
Maximum Release Rate, (Q10) _
Release Rate, (Q10) _
Normal Water Surface Elev. _
1
30 inches
4.91 sf
50 feet
0.00786
251.70 feet
256.70 feet
Width Weir— 48 inches
14.00 feet
12.00 sq. ft.
2.00 inches
1
0.02 sf
0.60
251.70 feet
0.40 feet
253.10 feet
3.00
15 feet
3.3
257.20 feet
6.74 cfs
3.65 cfs
251.70 feet
Water Surface Elev. @ Outlet (Qlo) = 255.13 feet
printed: 1/28/2022 3:59 PM
Page 2 of 3

Peak Inflow, (Qp) =>
Time to Peak Calculation: CN=
Q*=
vo1=
Time to Peak, (Tp) _>
(SCS TR-55)
34.70 cfs
84 P= 5.46 in.
3.69 in. (depth of runoff)
47,734 cf (vol. of runoff)
29.1 minutes
S= 1.90 in.
printed: 1/28/2022 3:59 PM
Page 3 of 3