C153349 Feasibility Study

• Contract/PO #: C153349
• Contractor Name: Brook Forest Water District
• Contract Type: Loan
• Water District: 9
• County: Jefferson
• Bill Number: SB 80-67
• Loan Projects - Doc Type: Feasibility Study

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when the well pumps are on than whe~ they are off.

Pressure surges and pressure fl~ctuations in the water distribution lines

occur whenever valves are opened or closed or when pumps cycle on and off.

The pressure surge is caused by a s~dden change in the water velocity. The

momentum of the water is transformed into a pulse of high preSsure which is

propagated back along the water line. A vibration is created in unrestrained

water lines which produces the familiar hammering sound associated with the

term "water-hammer."

For pressure surge analysis, it was assumed that the maximum probable

pressure i~crease was desired. This condition OCcurs when t~e check valves

in the pump discharge line close rapidly after the pump shuts off. Pressure

surges are relatively small during ~he normal starting of pu~ps. The minimum

pressure i~crease in the water mains due to surge pressures is estimated to

be 15 psi. This minimum value is c#used by rapid valve clos~res in the homes

of residen~s.

The following table, Table-12 lists the distribution line pressures for
static conditions, pumping periods, and surges.

TABLE: 12
PRESSURES IN THE WATES DISTRIBUTION MAINS.

LOCATION

APPROXIMATE
ELE:VATION

STATIC
PRESSURE
(psi)

DYNAMIC
(PUMPING)
PRESSURE
(psi)

MAXIMUM
SURGE
PRESSURE
(psi)

ZONE A (I) (Eastern Portion of District)

Ponderosa Way/Blue Spruce Lane 7800 155
Aspen Meadow Drive/Ponderosa Way 7945 92
Ponderosa Way/ponderosa Court 7980 77
Ponderosa Court/Lodgepole Drive 8030 56
-46-

158

183

94

110

79

95

57

72