1. Components of Water Networks Eng. Mona Al-Gharbawi Eng. Ayman Al-Afifi
Lecture 5
Components of Water Networks
By :
Eng. Mona Al-Gharbawi Eng. Ayman Al-Afifi

2. Network Appurtenances
Major operations within a water transport and distribution systems are:
Transmission.
Storage.
Pumping.

3. Water Transmission
This is the basic part of water distribution systems. Transmission consists of various types of pipes, joints, fittings, and connections that operate together with miscellaneous control equipment.
Pipes
Pipes convey water from one point to another and a careful
selection of pipe material is particularly important, because
it avoids the following bad consequences :

4. Increased water losses.
Increased energy losses.
Shorter pipe life time.
Expensive maintenance of the system.
Potential deterioration of water quality.
Frequent interruption of supply.

5. Pipes can be classified as follows according to the purpose they serve :
Trunk Mains : This is a pipe for the transport of potable, clean water from the water treatment plant or the water resource to the distribution area.
Secondary Mains : These pipes provide the basic structures of the distribution system. They are used to link main distribution pipes with the serves reservoirs or/and with the trunk distribution mains.
Distribution Mains : These pipes carry water from the secondary mains to the smaller consumers.
Service Pipes : These pipes bring water from the distribution mains directly to either a public stand post, yard connection or to a dwelling.

6. Pipes used in water supply are made of various materials and depending on their resistance to the backfill and shock loads they can be categorized in three large groups:
Rigid ( Iron , Pre-stressed concrete , Asbestos cement ).
Semi-rigid ( Steel, ductile iron ).
Flexible ( PVC, PE, HDPE, glass reinforced plastic, etc…).

7. Valves
Valves used in water distribution systems are distinguished by their purpose, operation principle and way of control. Generally they have these main tasks:
Flow and/or pressure regulation ( Flow control valves, pressure reducing valves, etc ).
Exclusion of part(s) of the network due to emergency or maintenance reasons ( Gate, or sluice valves ).
Protection of reservoirs and pumps in the system ( Float valves, check valves).
Air release from pipelines ( Air release valves ).

8. Fittings
Fittings are applied in case of interruption of pipelines, such as change in diameters, materials, pipeline direction or if valves and water meters have to be installed (e.g. different types of bends, branch, reducer, etc).
Water Meters
The purpose of metering in water distribution system is twofold:
It provides the system information about hydraulic behavior of the network
It is a basis for water billing.

9. Fire Hydrants
Required capacity, pressure and distance for hydrants vary from case to case and they are related to the potential risks and consequences from fire. Generally, the capacities are within the range m³ / hr, pressure from mwc and distances between 100 – 300 m.

10. Water Storage
Clear water storage facilities are part of any sizable water supply system. They can be located at the treatment plant, at the end of transmission system or at any other favorable place in the distribution system. There, they serve three general purposes:
Meeting variations in water demands often imposed on a distribution system.
Providing a reserve supply in emergency situations.
To eliminate the disadvantages of the direct pumping systems.

11. It should have a minimum storage equal to the fire demand.
Water tanks
Water tanks are storage containers for water, these tanks are usually storing water for human consumption.
Types of tanks
Ground Tanks :
It should have a minimum storage equal to the fire demand.
Elevated Tanks :
Its capacity is evaluated according to distribution needs, and is used when there is insufficient pressure in the network.

12. The required volume of Tanks
To calculate the capacity of the tank. Three quantities must be taken into consideration:
The needed supply (equals to the calculated demand).
Water quantities needed for the emergent maintenance, emergency storage is provided to sustain the communities needs during periods when the inflow to the reservoir is shut off , for example through the failure of the supply work , failure of pumping equipment , or need to take a supply line out of service for maintenance or repair.
Water quantities needed for fires.

13. Position of Tanks
There are some points must be considered when choosing the location of the tank:
The position should be at the center of the city and close enough to the consumption points, the central locations decreases friction losses by reducing the distance from supply point to the area served.
It must be at a high level in order to give sufficient pressure in the system they are to serve.

14. Water Pumping
Water pumps are devices designed to convert mechanical energy to hydraulic energy. They are used to move water from lower points to higher points with a required discharge and pressure head.
Pump Characteristic Curve
Pump manufacturers provide information on the performance of their pumps in the form of curves, commonly called pump characteristic curves (or simply pump curves). The pump characteristic curves are very important to help select the required pump for the specified conditions.

16. Water Distribution System Simulation

17. What does “ Simulation” means ??
Simulation is defined as the process of creating a model of an existing or proposed system in order to identify and understand those factors which control the system and/or to predict (forecast) the future behavior of the system. Almost any system which can be quantitatively described using equations and/or rules can be simulated.

18. A Water Network simulation implies the calculation of all the network pressure heads and flows together with reservoir levels, and for known pump and valve controls and consumer demands. Network simulations, which replicate the dynamics of an existing or proposed system, are commonly performed in the following situations :
When it is not practical for the real system to be directly subjected to experimentation, or for the purpose of evaluating a system before it is actually built.
To predict system response to events under a wide range of conditions without disrupting the actual system.
To anticipate problems in an existing or proposed system and solutions can be evaluated before time, money and materials are invested.

19. Assembling a model Reservoirs
A reservoir is an infinite source of water, which means that it can theoretically handle any inflow or outflow rate for any period of time, without running dry or overflowing.
Lakes, groundwater wells and clear wells at water treatment plants are often represented as reservoirs in water distribution system models.
Data Needed :
Water Surface Level.
Water quality.

20. Tanks Data Needed : Type of tank ( Ground, Elevated).
Tanks have a finite storage volume, and it is possible to completely fill or completely exhaust that storage.
Data Needed :
Type of tank ( Ground, Elevated).
Cross-section of tank ( Circular, Square , variable ).
Elevation.
Operating levels ( Vertical Parameters of the tank : minimum, initial, maximum).

21. Junctions
The primary use of a junction node is to provide a location for two or more pipes to meet. Junctions, however, do not need to be elemental intersections, as a junction may exist in an end of a single pipe (Typically referred to as a dead-end). The major role of a junction is to provide a location to withdraw water demand from the system or inject the inflows into the system.
Junction nodes typically do not directly relate to real-world distribution system components, since pipes are usually joined with fittings and flow are extracted from the system at any number of customer connections along the pipe.
Data Needed :
Position ( x , y ) , Elevation( z ).
Demand and Type of Demand ( Pattern ).

22. Pipes
A pipe conveys flow as it moves from one junction to another in a network.
Data Needed :
Start, End Junctions.
Diameter.
Material.
Length.

23. Pumps
A pump is an element that adds energy to the system in the form of increased hydraulic grade. Since water flows "downhill" (that is, from higher energy to lower energy), pumps are used to boost the head at desired locations to overcome piping head losses and physical elevation differences. Unless a system is entirely operated by gravity, pumps are an integral part of the distribution system.
Data Needed :
Elevation.
Pump Curve.
Operation.

24. Valves
A valve is an element that can be opened and closed to different extents to vary its resistance to flow, thereby controlling the movement of water through a pipeline.
Data Needed :
Elevation.
Diameter.

25. What we have done so far Preliminary Studies Demographical Data
Topographical Data
Water Consumption
Preliminary Studies
What we have done so far

26. Analysis of the Network
Preliminary Studies
Layout of the Network
Data Entry
Analysis of the Network
What’s Next ??

27. Questions