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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