CITY
OF ANAHEIM
PUBLIC WORKS ENGINEERING DEPARTMENT
SUBDIVISION SECTION
Grading
Design Manual
APPENDIX
H  Sample of Sump Pump Design
I.
CALCULATION OF TOTAL DYNAMIC HEAD (T.D.H.)
A.Static
Head:
(Maximum force main elevation  minimum wetwell elevation)
Elevation of force
main discharge: 100.24
Elevation floor of wetwell: 89.07
off
level:
0.50
87.57
Static head: 10.67
B.
FRICTION HEAD:
H = L x f
f = (V/1.318 x C x R 0.63) 1.852
V: Velocity fps
C: Hazen Williams coefficient
R: Hydraulic radius = D/4
1. Force main:
4" P.V.C.,
L = 70.36 ft, C = 150
Q = 283.33. G/P.M.
R = 0.0833
f = 0.0288
h= 709.36 x 0.0288 = 2.03 ft
2. Spool force
main:
4" D.I.P.,
L = 3 ft., c= 120
f = 0.0435*
h = 3 x 0.0435 = 0.13 ft.
3. Fittings (Valves
and Elbows):
Description

Quantity

Equivalent
length
of straight pipe

P.V.C.
to D.I.P. fitting 4" x 6" 
2
ea 
1.00
ft. 
Vertical
swing check valve 4" 
1
ea 
31.00
ft. 
90
elbow 4" 
2
ea 
22.00
ft. 
P.V.C.
4" 

1.50
ft. 
Tee
4" x 4" 4" 
1
ea 
17.00
ft. 
Reducer
3" x 4" 
1
ea 
0.35
ft 
Total 

72.85
ft. 
h
= 72.85 x 0.0435 * = 3.17 ft. 
T.D.H.
= 10.67 + 2.03 + 0.13 + 3.17 = 16 ft. 
II.
CALCULATION OF FLOAT SETTING IN WELL TO SATISFY PUMPS:
Well storage: 7.48
gal. x 4' x 4' = 119.68 gal.
Q = 283.33 G.P.M
Float setting in well: 283.33/119.68 = 1.99 ft. say 2 ft.
2 feet is float setting
between lead pump on and off position in well to satisfy pump cycle. (The
recessed area of the well was not considered in figuring the float setting
due to displacement of pumps and fitting).
