CE 102 - HYDRAULICS ENGINEERING

Supply System

WATER DISTRIBUTION

Water Distribution - Supply System

Definition

- Physical works that deliver water from the water source to the intended end point or USER.

Basic elements

• Water intakes - from surface waters and

groundwater

• Pumping stations

• External pipelines (conduits) - gravity

and (pumping) pressurised

Basic elements

• Reservoirs - collecting, service

(distribution), storage, (artificial) lakes

• Distribution(water supply) networks

• Pipelines and distribution networks

facilities - chambers, valves, fittings

IntroductionTo deliver water to individual consumers with

appropriatequality, quantity, and pressure in a community

setting requiresan extensive system of:

• Pipes.• Storage reservoirs.• Pumps.• Other related accessories.

Methods Of Supplying Water• Depending on the topography

relationship between the source of supply and the consumer, water can be transported by:

• Canals. • Tunnels.• Pipelines.

• The most common methods are:• Gravity supply• Pumped supply• Combined supply

Gravity Supply• The source of supply is at a sufficient

elevation above the distribution area (consumers).

Source

(Reservoir) Gravity-Supply

System

(Consumers)

so that the desired pressure can be maintained

Advantage of Gravity Supply

• No energy costs.• Simple operation (fewer mechanical parts,

independence of power supply, ….)• Low maintenance costs.• No sudden pressure changes

Pumped Supply

Source

(River/Reservoir)

Pumped Supply

Used whenever:• The source of water is lower than the area to

which we need to distribute water to (consumers)

• The source cannot maintain minimum pressure required.

pumps are used to develop the necessary head (pressure) to distribute water to the consumer and storage reservoirs.

Disadvantage of Pumped Supply

• Complicated operation and maintenance.• Dependent on reliable power supply.• Precautions have to be taken in order to enable

permanent supply:o Stock with spare partso Alternative source of power supply ….

Combined SupplyPumped-Storage Supply

• Both pumps and storage reservoirs are used.

Gravity supplyPumped supply

reservoir

reservoir

City

Sources of Water

• Aquifers (Groundwater)

• Surface Water

Sources Of Water

Aquifers (Groundwater)

• Primary source of drinking water

• Porous consolidated rock or unconsolidated soil

• Groundwater fills spaces

• Wells and pumps used to remove water

Sources Of WaterSurface Water • Lakes, reservoirs, rivers• Rivers dammed to create

reservoirs• Reservoirs store water during

heavy rain/snow

Water Treatment

• Amount of treatment

depends on quality of

the source

• Ground water requires

less treatment than

surface water

The city of Salem water treatment facility withdraws water from the North Santiam

River.

Water Storage

Pumped to Storage Tank

• Storage

• Water pressure

opsi

o1 psi = 2.31 feet of water

Types of Reservoirs

• Underground reservoirs.

• Small ground level reservoirs.

• Large ground level reservoirs.

• Overhead tanks.

Water Distribution System• Consists of water lines,

fittings, valves, service lines,

meters, and fire hydrants

• Loop system more desirable

than branch system

– Isolation valves

– Water flows in more than

one direction

LOOP SYSTEM

BRANCHSYSTEM

Water Supply Risk

Risk Concepts:

Risk = (Probability of failure) * (consequence of such

failure)

Probabilities impacting on water supply

Things going wrong and the uncertaintiesassociated with it, for example:• Pipeline failures

– How often does it happen?– How long does it take to repair?

• Power failures• Local soil conditions – dolomitic areas• Water demand

Consequential damage

Vary diverse, but also unique, for example:

• Type of consumer• Area where the incidence occurred.• Climate• Sanitation services provided

About The Risk

• earthquakes = minutes• floods = days• droughts = weeks• man made threats = ?

The concentration of human population and economic activity in urban center raises the level of risks.

Man made threats: what has changed ?

• Matters of security are now definitely part of the job.

• New relationships are being deployed between the waterutilities and the authorities.

• New challenges appear with new constraints but alsowith new opportunities to improve the water supplysecurity.

Why is it important?

• System failures do occur.

• Impact on people / consumers.

• Reliability of supply.

• Impacting on new infrastructure.

• Impact on repair and maintenance

work.

JULIE MAE CUCHAPIN BALIOGB S C E – I V

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