Water Distribution 2.0

Question 1

What are the most common forms of chlorine used for field disinfection?
A. Chlorine dioxide, hydrogen chloride
B. Calcium hypochlorite, sodium hypochlorite
C. H.T.H., sodium chlorite
D. Chloramine, chlorate

Answer 1

B. Calcium hypochlorite, sodium hypochlorite

Question 2

Which of the following does not need cathodic protection?
A. Hydropneumatic tank
B. PVC pipe
C. Steel pipe
D. Ductile Iron pipe

Answer 2

B. PVC pipe

Question 3

Choose the option that best describes the main objectives of a water distribution system.
A. Maintain a minimum positive system pressure at all times and protect potable water from contamination.
B. To minimize costs and downtime.
C. To enable the operating authority to shut off customers for non-payment and ensure equal water allocation.
D. Maintain the system to ensure that the O & M budget is completely spent each year.

Answer 3

A. Maintain a minimum positive system pressure at all times and protect potable water from contamination.

Question 4

Which of the following is true?
A. Pipe roughness (“C”) factors are used to calculate friction losses in medium and large diameter pipes only.
B. Friction losses for new pipe are negligible.
C. Pipes with high C values will have lower friction losses than pipes with low C values.
D. Corroded pipes have higher C values than new pipes.

Answer 4

C. Pipes with high C values will have lower friction losses than pipes with low C values.

Question 5

A hydraulic grade line is:
A. The groundwater level of a shallow aquifer.
B. The elevation at which a distribution line must be laid to ensure adequate velocity.
C. A hypothetical line used to indicate the relative pressures in a system.
D. A line designating the depth to which a trench must be cut when laying a trunk line.

Answer 5

C. A hypothetical line used to indicate the relative pressures in a system.

Question 6

Why should distribution system pressure never be allowed to fall below atmospheric pressure?
A. Inadequate volumes of water will cause line breaks and water losses.
B. Low or negative pressure may result in contamination from infiltration, backflow or cross connections.
C. Low pressure systems are prone to breakdown and require considerable maintenance.
D. Lower pumping costs will permit a more comprehensive maintenance program.

Answer 6

B. Low or negative pressure may result in contamination from infiltration, backflow or cross connections.

Question 7

What is the normal range of distribution pressure that should be maintained?
A. 140 to 275 kPa (20 - 40 psi)
B. 100 to 200 kPa (14.5 - 29 psi)
C. 200 to 400 kPa (29 - 58 psi)
D. 275 to 550 kPa (40 - 80 psi)

Answer 7

D. 275 to 550 kPa (40 - 80 psi)

Question 8

What is the purpose of a thrust block?
A. To provide support for the pipe where the flow changes direction.
B. To positively isolate a section of pipe to prevent backflow or flooding of a worksite.
C. To allow an “air cushion” to dampen water hammer pressure fluctuations.
D. To allow for sudden start/stop situations during operation of line shaft turbine pumps.

Answer 8

A. To provide support for the pipe where the flow changes direction.

Question 9

What is meant by water hammer?
A. A spark proof hammer used in the water and wastewater industry.
B. A pressure wave caused by rapid increase or decrease of water velocity in a piping system.
C. A hydraulic tamper used to compact bedding for large diameter pipelines.
D. The noise created by expansion or contraction of piping caused by temperature change.

Answer 9

B. A pressure wave caused by rapid increase or decrease of water velocity in a piping system.

Question 10

How can water hammer be reduced or eliminated?
A. By opening or closing all values completely.
B. By eliminating the possibility of vortexing on the suction side of the pumps.
C. By opening and closing valves slowly.
D. By opening or closing valves quickly.

Answer 10

C. By opening and closing valves slowly.

Question 11

Which of the following identifies the main functions of treated water reservoirs?
A. To protect the raw water from contamination due to industrial or storm sewer discharges.
B. They ensure that chemical feed pumps are able to maintain consistent dosages.
C. They ensure that water is properly “cured” before being metered.
D. To provide storage for later demands and reduce the required size and capacity of mains and booster stations.

Answer 11

D. To provide storage for later demands and reduce the required size and capacity of mains and booster stations.

Question 12

Which of the following identifies factors which must be considered when selecting pipe for use in a distribution system?
A. Low friction loss, availability and submergence.
B. Compatibility with existing pipe material, cost and lifestyle.
C. Durability, corrosion resistance and compatibility with potable water.
D. Strength, ease of handling and O. H. & S. certification.

Answer 12

C. Durability, corrosion resistance and compatibility with potable water.

Question 13

What are four of the common types of pipe used in the water distribution industry?
A. Butylene, Styrene, clay tile, galvanized
B. P.V.C., A.C., steel, ductile iron
C. C.P.P., ductile iron, flex-lox, A.C.
D. P.C.B., steel, butylene, A.C.

Answer 13

B. P.V.C., A.C., steel, ductile iron

Question 14

Why is proper pipe bedding important?
A. It provides pipe support and can reduce earth loadings on the pipe.
B. It allows for expansion and provides corrosion resistance.
C. Removed trench material can be reclaimed.
D. To ensure separation from the water table.

Answer 14

A. It provides pipe support and can reduce earth loadings on the pipe.

Question 15

Which of the following is true?
A. Class D bedding uses a concrete cradle or arch to support the pipe.
B. In Class B bedding, the pipe is supported by sand and/or silt.
C. In Class C bedding, the pipe is placed directly on the bottom of a carefully-shaped excavation.
D. In Class A bedding, little care is taken to shape the pipe foundation and to compact bedding material around the pipe

Answer 15

C. In Class C bedding, the pipe is placed directly on the bottom of a carefully-shaped excavation.

Question 16

What is the normal pressure used for pressure testing distribution system mains?
A. Pipe diameter (in cm) multiplied by 22.2.
B. 660 kPa (100 psi) or 2 times the operating pressure whichever is greater.
C. 1,000 kPa (150 psi) or 1.5 times operating pressure, whichever is greater.
D. 660 kPa (100 psi) or 2 times the operating pressure whichever is less.

Answer 16

C. 1,000 kPa (150 psi) or 1.5 times operating pressure, whichever is greater.

Question 17

What are the last two steps to follow when disinfecting a water main?
A. Ensure that all main valves are operational and calculate the amount of chlorine to be used.
B. Flush chlorine from the main and test for bacteriological quality.
C. Locate all main valves and notify residents in the area.
D. Overhaul all hydrants and place back in service.

Answer 17

B. Flush chlorine from the main and test for bacteriological quality.

Question 18

What are two functions of valves in a distribution system?
A. Isolate fire hydrants and isolate sections of the system.
B. Direct flow in the system, restrict flows during water rationing.
C. Maintain remote reservoir water levels, provide an air gap to prevent backflow.
D. Maintain positive pressure at all times, direct water flow to minimize dead zones.

Answer 18

A. Isolate fire hydrants and isolate sections of the system.

Question 19

Which of the following choices best describe fire hydrant functions?
A. Provide a location for line flushing, to eliminate water hammer.
B. Supply water for firefighting; prevent line collapse by allowing air into the system.
C. Allow for insertion of swabs or pigs for main cleaning, support the water main when settling occurs.
D. Provide locations for hydraulic testing of the system, supply water for firefighting.

Answer 19

D. Provide locations for hydraulic testing of the system, supply water for firefighting.

Question 20

In areas with high water tables, how can hydrant freezing be prevented?
A. Install only non-freezing hydrants.
B. Pump out the hydrant.
C. Install heat tape on all hydrants.
D. Ensure that they are not used in winter.

Answer 20

B. Pump out the hydrant.

Question 21

How often should hydrants be inspected?
A. At least twice yearly.
B. Only during repair or replacement.
C. Every 10 years.
D. Whenever a problem is suspected.

Answer 21

A. At least twice yearly.

Question 22

The most common type of valve used in a distribution system is:
A. Ball valve
B. Diaphragm valve
C. Gate valve
D. Globe valve

Answer 22

C. Gate valve

Question 23

Identify the normal types of treated water storage facilities.
A. Underground reservoirs, elevated tanks, standpipes, concrete tanks.
B. Elevated tanks, secondary clarifiers, pipe galleries.
C. Standpipes, hydropneumatic tanks, open lagoons.
D. Concrete tanks, low lift pumping stations, slow sand filters.

Answer 23

A. Underground reservoirs, elevated tanks, standpipes, concrete tanks.

Question 24

Why is reservoir (treated water) level control important?
A. To maintain levels within specified limits, to prevent short circuiting.
B. To prevent pump damage caused by low water level, to avoid overflow and water loss.
C. To provide pressure control in gravity systems, to allow enough flash mixing time.
D. To provide adequate storage for emergency use, to prevent backflow.

Answer 24

B. To prevent pump damage caused by low water level, to avoid overflow and water loss.

Question 25

Choose the three methods of controlling corrosion of metallic components of a distribution system. A. Metallic coatings (zinc, aluminum), soften the water using sodium ion exchange. B. Cement mortar, raise the water-temperature to-eliminate corrosion. C. Cathodic protection, lower the water to a pH that would be non-corrosive. D. Chemical additives, (lime, soda ash, orthophosphates), cathodic protection, non-metallic coatings (epoxies, silicate paints).

Answer 25

D. Chemical additives, (lime, soda ash, orthophosphates), cathodic protection, non-metallic coatings (epoxies, silicate paints).

Question 26

What factors must be considered when painting steel tanks. A. Coating life, peak hour demand B. Surface preparation, effect on water potability C. Inspection, tank loading D. Curing, raw water quality

Answer 26

B. Surface preparation, effect on water potability

Question 27

What are the possible effects of freezing in treated water reservoirs? A. Reduced capacity, high pH. B. Reservoir corrosion, due to high dissolved oxygen, reduced capacity. C. Structural damage, damage to pumps or other equipment. D. Loss of level indication, algae blooms.

Answer 27

C. Structural damage, damage to pumps or other equipment.

Question 28

What are two ways of preventing freezing in treated water reservoirs? A. Varying the water level frequently, re-pumping or circulating reservoir contents. B. Insulation, paint the reservoir a light neutral colour. C. Maintain a constant reservoir level, ensure that the tank is well grounded. D. Remove heat sources, insulation.

Answer 28

A. Varying the water level frequently, re-pumping or circulating reservoir contents.

Question 29

Why should distribution system water quality be monitored? A. To confirm potability of the supply and ensure adequate staffing at the water treatment plant. B. To determine possible sources of contamination and to keep main repair equipment available. C. To confirm potability after construction or repair and to respond to customer complaints. D. To detect changes in water quality and monitor industrial discharges.

Answer 29

C. To confirm potability after construction or repair and to respond to customer complaints.

Question 30

Which of the following lists three of the ways of locating leaks in a water distribution system? A. Meter readings, bacteriological testing, pipe stress testing. B. Listening devices, surface signs, lower than normal consumption. C. Probes, reduced pressure backflow prevention devices, pressure testing. D. Surface signs, listening devices, meter readings.

Answer 30

D. Surface signs, listening devices, meter readings.

Question 31

Why is backflow (or back siphonage) in a distribution system potentially dangerous? A. The potential for contamination of the distribution system exists. B. The reservoir may drain back to the treatment plant, causing flooding and low reservoir alarms. C. Water hammer may occur causing infrastructure damage. D. Structural failure may occur.

Answer 31

A. The potential for contamination of the distribution system exists.

Question 32

Which of the following devices can be used to prevent backflow? A. Vacuum breakers, swing check valves, venturi tubes. B. Air gap, double check valves, reduced pressure backflow prevention devices. C. Butterfly valves, remote solenoid valves, pressure regulating valves. D. Plug valves, rupture discs, using an elevated tower to gravity feed the system.

Answer 32

B. Air gap, double check valves, reduced pressure backflow prevention devices.

Question 33

What is the purpose of water main flushing? A. To ensure that water mains are protected from external corrosion. B. Familiarization of collection system workers with the system. C. Disposing of surplus water volumes. D. To remove deposits, sediments and minor encrustations from the main.

Answer 33

D. To remove deposits, sediments and minor encrustations from the main.

Question 34

What is the purpose of a pig or foam swab in water distribution? A. To scour debris and encrustations from the main. B. To disinfect and kill any bacteriological build up in the main. C. To identify the peak flow available in the supply main. D. To prevent corrosion by laying down a thin layer of protective material.

Answer 34

A. To scour debris and encrustations from the main.

Question 35

How often should the following meters be tested? A. Small - 5 to 10 years; Large - every 10 years B. Small - 1 to 4 years; Large - 5 to 10 years C. Small - 5 to 10 years; Large - 1 to 4 years D. Small - 3 to 5 years; Large - every 10 years

Answer 35

C. Small - 5 to 10 years; Large - 1 to 4 years

Question 36

The requirement of special butt-welding equipment and training to fuse joints is a disadvantage associated with ________ pipe. A. Polyethylene B. Steel C. Asbestos Cement D. Cast Iron

Answer 36

A. Polyethylene

Question 37

One advantage of a tree distribution system, as opposed to a loop/grid distribution system, is: A. The lack of dead-end sections. B. Lower capital investment. C. Allows water to be supplied from two or more directions. D. More water circulation.

Answer 37

B. Lower capital investment.

Question 38

Which of the following is not part of a distribution system? A. Hydrant B. Reservoir C. Lift Station D. Corporation Stop

Answer 38

C. Lift Station

Question 39

Which is not an indicator of a possible leak in the distribution system? A. Vibration felt on hydrants, valves, or other appurtenances. B. Large bodies of standing water during a dry period. C. Formation of sinkholes. D. Decrease in distribution system pressure at peak usage periods.

Answer 39

D. Decrease in distribution system pressure at peak usage periods.

Question 40

Which backflow prevention device is best used when dangerous materials are present at the water usage location? A. Air Gap Separation B. Reduced Pressure Device C. Double Check Device D. Vacuum Breaker

Answer 40

B. Reduced Pressure Device