Water Distribution System Chapter 1

Front 1

Acid rain

Back 1

Precipitation that has been rendered (made) acidic by airborne pollutants

Front 2

Algae (3)

Back 2

Microscopic plants containing chlorophyll that live floating or suspended in water. They also may be attached to structures rocks or other submerged surfaces.

Excess algal growths can impart tastes and odours to potable water. Algae produce oxygen during sunlight hours and use oxygen during the night hours.

Their biological activities appreciably affect the pH, alkalinity, and dissolved oxygen of the water

Front 3

Algal bloom

Back 3

Sudden, massive growths of microscopic and macroscopic plant life, such as green or blue-green algae, which develop in lakes, reservoirs, and lagoons under the proper conditions

Front 4

Anaerobic

Back 4

A condition in which atmospheric or dissolved oxygen (DO) is not present in the aquatic (water) environment

Front 5

Aquifer

Back 5

A natural, underground layer of porous, water-bearing materials (sand, gravel) usually capable of yielding a large amount or supply of water

Front 6

Back pressure

Back 6

A pressure that can cause water to backflow into the water supply when a user's water system is at a higher pressure than the public water system

Front 7

Backflow

Back 7

A reverse flow condition, created by a difference in water pressures, that causes water to flow back into the distribution pipes of a potable water supply from any source or sources other than an intended source. Also see backsiphonage

Front 8

Backsiphonage

Back 8

A form of backflow caused by a negative or below atmospheric pressure within a water system. Also see backflow

Front 9

Capillary action

Back 9

The movement of water through very small spaces dye to molecular forces

Front 10

Capillary fringe

Back 10

The porous material just above the water table that may hold water by capillarity (a property of surface tension that draws water upward) in the smaller void spaces

Front 11

Carcinogen

Back 11

Any substance that tends to produce cancer in an organism

Front 12

Chloramines

Back 12

Compounds formed by the reaction if hypochlorous acid (or aqueous chlorine) with ammonia

Front 13

Cross-connection

Back 13

A connection between a drinking (potable) water system and an unapproved water supply or between a storm drain system and a sanitary collection system. Less frequently, a connection between two sections of a collection system to handle anticipated overloads of one system

Front 14

Direct runoff

Back 14

Water that flows over the ground surface directly into streams, rivers, or lakes. Also called storm runoff.

Front 15

Electrochemical reaction

Back 15

Chemical changes produced by electricity (electrolysis) or the production of electricity by chemical changes (galvanic action). In corrosion, a chemical reaction us accompanied by the flow of electrons through a metallic path. The electron flow may come from an external force and cause the reaction, such as electrolysis caused by a direct current (DC) electric railway, or the electron flow may be caused by chemical reaction, as in the galvanic action of a flashlight dry cell

Front 16

Entrain

Back 16

To trap bubbles in water either mechanically through turbulence or chemically through a reaction; or to trap one substance or material by another substance or material

Front 17

Head

Back 17

The vertical distance, height, or energy of water above a reference point. A head of water may be measured in either height (feet or meters) or pressure (pounds per square inch or kilograms per square centimeter). Also see discharge head, dynamic head, static head, suction head, suction lift, and velocity head.

Front 18

Impermeable

Back 18

Not easily penetrated. The property of a material or soil that does not allow, or allows only with great difficulty, the movement or passage of water

Front 19

Interface

Back 19

The common boundary layer between two substances, such as water and solid (metal); or between two fluids, such as water and a gas (air); or between a liquid (water) and another liquid (oil)

Front 20

Macroscopic organisms

Back 20

Organisms big enough to be seen by the eye without the aid of a microscope

Front 21

Overturn

Back 21

The almost spontaneous mixing of all layers of water in a reservoir or lake when the water temperature becomes similar from top to bottom. This may occur in the fall/winter whether surface waters cool to the same temperature as the bottom waters and in the spring when the surface waters warm after the ice melts. Also called turnover.

Front 22

Palatable

Back 22

Water at a desirable temperature that is free from objectionable tastes, odours, colors, and turbidity. Pleasing to the senses.

Front 23

Potable water

Back 23

Water that does not contain objectionable, pollution, contamination, minerals, or infective agents and is considered satisfactory for drinking

Front 24

Raw water

Back 24

Water in it's natural state, before any treatment, especially as it enters the first treatment process of a water treatment plant

Front 25

Soft water

Back 25

Water having a low concentration of calcium and magnesium ions. According to US Geological Survey guidelines, soft water is water having a hardness of 60 milligrams per liter or less

Front 26

Stratification

Back 26

The formation of separate layers (of temperature, plant life, or animal life) in a lake or reservoir. Characteristics within each layer are similar; for instance, all water in the same layer has the same temperature. Also see thermal stratification.

Front 27

Subsidence

Back 27

The dropping or lowering of the ground surface as a result of removing excess water (overdraft or overpumping) from and aquifer. After excess water has been removed, the soil will settle, becoming compacted, and the ground surface will drop, which can cause the settling or underground utilities

Front 28

This (trihalomethanes)

Back 28

Derivatives of methane, CH4, in which three halogen atoms (chlorine or bromine) are substituted for three of the hydrogen atoms. Often formed during chlorination by reactions with natural organic materials in the water. The resulting compounds (THMs) are suspected of causing cancer.

Front 29

Topography

Back 29

The arrangement of hills and valleys in a geographic area

Front 30

Transpiration

Back 30

The process by which water vapour is released to the atmosphere by living plants. This process is similar to people sweating. Also called evapotranspiration

Front 31

Turbidity

Back 31

The cloudy appearance of water caused by the presence of suspended and colloidal matter. In the waterworks field, a turbidity measurement is used to indicate the clarity of water. Technically, turbidity is an optical property of the water based on the amount of light reflected by suspended particles. Turbidity cannot be directly equated to suspended solids because white particles reflect more light than dark-coloured particles and many small particles will reflect more light than an equivalent large particle.

Front 32

Tubercle

Back 32

A crust of corrosion products (rust) that builds up over a pit caused by the loss of metal due to corrosion

Front 33

Vortex

Back 33

A revolving mass of water that forms a whirlpool. This whirlpool is caused by water flowing out of a small opening un the bottom of a basin or reservoir. A funnel-shaped opening is created downward from the water surface.

Front 34

Water cycle

Back 34

The process of evaporation of water into the air and its return to earth by precipitation (rain or snow). This process also includes transpiration from plants, groundwater movement, and runoff into rivers, streams, and the ocean. Also see hydrologic cycle.

Front 35

Water table

Back 35

The upper surface of the zone of saturation of groundwater in an unconfined aquifer

Front 36

Why has it become necessary to conserve and properly budget our water sources?

Back 36

Because water is a limited resource and it's sustainability is essential to the planet's survival

Front 37

How are water shortages and energy consumption linked together?

Back 37

As groundwater levels fall, more energy is required to pump water from deeper levels of the basin.

Front 38

Why do many sources of water need treatment?

Back 38

To remove contaminants and provide potable water to the end consumer

Front 39

Name three ways groundwater may become contaminated?

Back 39

Seawater contamination

Seepage from septic tank leeching systems

Agricultural drainage systems

Improper disposal of hazardous wastes in sanitary landfills and dumps

Surface runoff into poorly constructed wells

Front 40

List the 2 major sources of water supplies.

Back 40

Groundwater

Surface water

Front 41

What is the water (hydrologic) cycle?

Back 41

Is the natural movement of water through means of runoff, evaporation, transpiration, condensation and precipitation.

Front 42

What are the general water quality characteristics of surface water supplies?

Back 42

Low calcium and magnesium content (soft water)

Turbidity

Suspended solids

Some colour

Microbial contamination

Front 43

What items should be considered before selecting a location and constructing a water supply intake located in a river or stream? (7)

Back 43

Upstream pollution

River bottom scouring

Changing channels

Design of intake to withstand floods

Heavy silting

Ice

Adverse runoff

Front 44

How can provisions be made to allow recreation on water supply lakes and reservoirs without endangering water quality?

Back 44

Requires proper construction and location of:

Boat launching ramps

Boat harbours

Picnic and camping areas

Fishing

Open beach areas away from intake area

Wastewater collection, treatment and disposal facilities

Front 45

What are the general water quality characteristics of ground water supplies?

Back 45

High concentration of dissolved solids

Dissolved gases

Hard water

No suspended solids

No microbial contamination (usually)

Front 46

What causes the flow of groundwater within an aquifer?

Back 46

Difference in head (energy) between two locations (for example, a higher area of recharge and a lower area of recharge)

Front 47

How can the sustained yield of an aquifer be exceeded?

Back 47

By pumping at a rate that exceeds the rate of replacement.

Front 48

List some of the possible uses of reclaimed wastewater?

Back 48

Greenbelt (parks) areas

Golf course irrigation

Industrial reuse

Groundwater recharge (possible exception)

Landscape impoundments

Wetlands/marsh enhancement

Front 49

How much treatment should reclaimed water receive before use?

Back 49

Should be appropriate for the intended use. The greater the potential risk to the public, the more extensive the treatment needs to be according to the regulatory agency.

Front 50

Why have water quality standards been prepared and used by the waterworks industry?

Back 50

To provide quality control and ensure the acceptability of the product.

Front 51

Drinking water quality standards can generally be categorized as being related either to _______ or _______.

Back 51

Health or Aesthetics

Front 52

MCL stands for what three words?

Back 52

Maximum Contaminant Levels

Front 53

Water quality is the general term used to describe which characteristics of a water supply (3)?

Back 53

Composite chemical

physical

biological

Front 54

A domestic water supply is considered to be of good quality when it meets what guidelines or criteria (4)?

Back 54

Free of disease-causing organisms and toxic chemicals

Attractive in taste and appearance

Chemical composition produces no corrosive or scale-forming effects on water distribution system

Satisfies requirements of domestic and industrial consumers

Front 55

What are the consequences of delivering poor quality water to the consumer(2)?

Back 55

Not acceptable to consumer because of it's appearance or taste

Illness or death

Front 56

What are trihalomethanes (THMs)?

Back 56

Derivatives of methane CH4 in which three halogen atoms (chlorine or bromine) are substituted for three of the hydrogen atoms.

Often formed during chlorination by reactions with natural organic materials in the water.

The resulting compounds (THMs) are suspected of causing cancer.

Front 57

What physical qualities of water are important to the consumers (6)?

Back 57

Colour

Turbidity

Taste

Odour

Temperature

Macroscopic organisms

Front 58

Where might contamination of water occur (4)?

Back 58

At source of supply

Water treatment plant

Distribution system storage facilities

Water mains

Front 59

How can water quality be degraded in the distribution system (9)?

Back 59

Cross-connections

Corrosion

Biological growth and activity

High temperatures

Unusual flows

Time in system

Dead ends

Age of facilities

Operational procedures

Front 60

Why are natural source waters never completely pure (9)?

Back 60

During precipitation and their passage over or through the ground, they can acquire a wide variety of dissolved or suspended impurities

Front 61

How can surface waters become contaminated or degraded?

Back 61

Decaying vegetationMinerals in soilsWaste discharges and spillsRefuse disposalRecreationConstructionAnimal activitiesAlgae growth and weedsRadioactive fallout

Front 62

How can groundwater become contaminated or degraded (8)?

Back 62

Poorly constructed wells

Surface water moving above the groundwater table

Contaminants at or near the ground surface

Leaching from wastewater operations or disposals

Spills

Humic materials

Flood waters

Passage through mineralized formations

Front 63

What problems can be created by improper chlorination in water treatment plants (3)?

Back 63

Pathogenic organisms entering the distribution system

Formation of trihalomethanes

Tastes and odours

Front 64

What is the most frequently reported cause of water-borne disease outbreaks in the United states?

Back 64

Backflow of unacceptable substances through cross-connections to distribution systems

Front 65

How can corrosion cause health problems?

Back 65

Heart disease caused by elevated levels of lead, cadmium, copper, zinc, asbestos and certain organic compounds found in water being served from distribution systems as a result of corrosive action.

Front 66

Slime growths can cause what problems in distribution systems?

Back 66

Tastes and odours

Accelerated corrosion

Reduced flow

Front 67

Which form of chlorine is most effective against biofilms?

Back 67

Chloramines

Front 68

What impacts does water temperature have on distribution system water quality?

Back 68

High temperatures tend to speed the rate of chemical reactions and increase biological growth rates.

Biological decomposition may be intensified by summer temperatures, and chlorine demand may be considerably greater so residuals will not carry as far in the distribution system in summer

Front 69

What problems can be caused by low flows?

Back 69

Changes in water velocity and flow reversals can result in sediments being stirred up and carried along until they reach the consumer

Low circulation and stagnant water can result in the growth of organisms, formation of sediment and corrosion products, depletion of oxygen, and increased tastes and odours

Turbulence can entrain air into the supply causing milky water

Front 70

How is water affected by length of time it remains in a distribution system?

Back 70

The longer water remains in the system, the more time is available for chemical and biological changes to take place

Front 71

What problems can develop as transmission and storage facilities become older (3)?

Back 71

More maintenance

Gradual deterioration in protection against corrosion can lead to water quality issues

Ruptures in pipes become more frequent

Front 72

What problems can develop at the interface where distribution pipe and water meet?

Back 72

Reduced flows permit greater chemical and biological activity at the interface where the pipe and water meet.

Front 73

Why may chlorination treatment not be effective at the dead end of a water main?

Back 73

Because of increased chlorine demand by organics, biological forms, and corrosion products

Front 74

What is the major quality concern regarding coal tar-lined pipe or plastic pipe?

Back 74

The possibility of leaching of material from the pipe or the lining by the water.

Front 75

How can water be protected from contaminants that enter the system during construction of new mains and repair of old mains?

Back 75

To ensure the safety of the delivered water, proper protective, cleaning, and disinfection practices must be followed.

When lines are being repaired, keep the hole dewatered to prevent possible contamination of the water line.

After repair, flush the line downstream.

After flushing, disinfect the line before being returned to service.

Front 76

What is the purpose of air valves (or some form of air bleed valve)?

Back 76

They are important to relieve entrapped air and to help prevent milky water and surge problems when lines are being filled.

Front 77

What problem might result from hydrant testing and flushing programs?

Back 77

Dirty water complaints

Front 78

How can open reservoirs become contaminated?

Back 78

Vandalism

Windblown and atmospheric contaminants

Animals including birds and rodents

Illegal bathing

Fishing

Front 79

Why can a poorly constructed reservoir roof be worse than no roof at all in terms of contamination?

Back 79

Bird droppings, dust and other materials that accumulate and roof gets washed into the reservoir.

Front 80

What are some of the problems associated with below-ground reservoirs?

Back 80

Subject to contamination by leaching through cracks in side walls

Nearby septic systems or wastewater facilities are of special concern

Susceptible to flooding by surface stormwater and windblown contamination

Easier to vandalize

Front 81

Why should the water level in storage facilities not be allowed to get too low?

Back 81

A vortex will be formed in the water being discharged.

Air may be entrained or materials that have settled ro the bottom of the reservoir may be stirred up and get into the mains and the customers' service lines.

Front 82

Why is there a need for water system operators?

Back 82

Needed to operate, maintain, repair, and manage water distribution systems, as well as interact with the public they serve.

Responsible to deliver safe and pleasant drinking water from their systems.

Responsible for the health and well-being of the community served by the water system

Front 83

What influences the knowledge and skills operators are required to have for their jobs?

Back 83

The size and type of water distribution system

Front 84

Who hires water system operators (4)?

Back 84

City

Water agency or district

Private utility company

Large industries that operate their own water system facilities

Front 85

Why should water system operators discuss proposed facilities with engineers?

Back 85

Your jobs is to discuss with the engineer how these new facilities could be operated, maintained, and repaired.

Make suggestions on how these jobs could be done more easily

Be sure there is adequate room for maintenance and repair equipment, even insuring adverse weather conditions

Front 86

Why are adequate and reliable records very important?

Back 86

Without adequate, reliable records of important phases of operation and maintenance, the effectiveness of your operation has not been documented (recorded).

Also, accurate records are required by regulatory agencies for compliance with the drinking water regulations of the Safe Drinking Water Act

Front 87

To whom might you have to explain the purpose and operation of your facilities?

Back 87

Civic organizations

School classes

Representatives of news media

City council members or directors

Front 88

Why is the appearance of pump stations and elevated tanks and the grounds around them important?

Back 88

If facilities are run down and unkempt, you will be unable to convince the public that you are going a good job.

Front 89

Why is safety important?

Back 89

Work in traffic and excavating for the installation or repair of pipes can be extremely hazardous.

Explosive conditions can develop when painting the inside of an elevated tank if adequate ventilation is not provided

Most accidents result from carelessness or negligence.