Lecture 4 Components of Water Networks Network Appurtenances

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Lecture 4 Components of Water Networks

Lecture 4 Components of Water Networks

Network Appurtenances � Major operations within a water transport and distribution systems are: 1.

Network Appurtenances � Major operations within a water transport and distribution systems are: 1. Transmission. 2. Storage. 3. Pumping.

Water Transmission �This is the basic part of water distribution systems. Transmission consists of

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. 1. 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 :

1. Increased water losses. 2. Increased energy losses. 3. Shorter pipe life time. 4.

1. Increased water losses. 2. Increased energy losses. 3. Shorter pipe life time. 4. Expensive maintenance of the system. 5. Potential deterioration of water quality.

 Pipes can be classified as follows according to the purpose they serve :

Pipes can be classified as follows according to the purpose they serve : 1. 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. 2. 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. 3. Distribution Mains : These pipes carry water from the secondary mains to the smaller consumers. 4. Service Pipes : These pipes bring water from the distribution mains directly to either a public stand post, yard connection or to a dwelling.

 Pipes used in water supply are made of various materials and depending on

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: 1. Rigid ( Iron , Pre-stressed concrete , Asbestos cement ). 2. Semi-rigid ( Steel, ductile iron ). 3. Flexible ( PVC, PE, HDPE, glass reinforced plastic, etc…).

2. Valves � Valves used in water distribution systems are distinguished by their purpose,

2. Valves � Valves used in water distribution systems are distinguished by their purpose, operation principle and way of control. Generally they have these main tasks: 1. Flow and/or pressure regulation ( Flow control valves, pressure reducing valves, etc ). 2. Exclusion of part(s) of the network due to emergency or maintenance reasons ( Gate, or sluice valves ). 3. Protection of reservoirs and pumps in the system ( Float valves, check valves). 4. Air release from pipelines ( Air release valves ).

3. Fittings are applied in case of interruption of pipelines, such as change in

3. 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). 4. 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.

5. Fire Hydrants � Required capacity, pressure and distance for hydrants vary from case

5. 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 30 - 50 m³ / hr, pressure from 10 -100 mwc and distances between 100 – 300 m.

Water Storage Clear water storage facilities are part of any sizable water supply system.

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.

Water tanks are storage containers for water, these tanks are usually storing water for

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.

The required volume of Tanks To calculate the capacity of the tank. Three quantities

The required volume of Tanks To calculate the capacity of the tank. Three quantities must be taken into consideration: 1. The needed supply (equals to the calculated demand). 2. 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. 3. Water quantities needed for fires.

Position of Tanks There are some points must be considered when choosing the location

Position of Tanks There are some points must be considered when choosing the location of the tank: 1. 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. 2. It must be at a high level in order to give sufficient pressure in the system they are to serve.

Water Pumping Water pumps are devices designed to convert mechanical energy to hydraulic energy.

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.

Water Distribution System Simulation

Water Distribution System Simulation

What does “ Simulation” means ? ? Simulation is defined as the process of

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.

 A Water Network simulation implies the calculation of all the network pressure heads

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 : 1. 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. 2. To predict system response to events under a wide range of conditions without disrupting the actual system. 3. To anticipate problems in an existing or proposed system and solutions can be evaluated before time, money and materials are invested.

Assembling a model Reservoirs A reservoir is an infinite source of water, which means

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 : 1. Water Surface Level. 2. Water quality.

Tanks have a finite storage volume, and it is possible to completely fill or

Tanks have a finite storage volume, and it is possible to completely fill or completely exhaust that storage. Data Needed : 1. Type of tank ( Ground, Elevated). 2. Cross-section of tank ( Circular, Square , variable ). 3. Elevation. 4. Operating levels ( Vertical Parameters of the tank : minimum, initial, maximum).

Junctions � The primary use of a junction node is to provide a location

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 : 1. Position ( x , y ) , Elevation( z ). 2. Demand Type of Demand ( Pattern ).

Pipes A pipe conveys flow as it moves from one junction to another in

Pipes A pipe conveys flow as it moves from one junction to another in a network. Data Needed : 1. Start, End Junctions. 2. Diameter. 3. Material. 4. Length.

Pumps A pump is an element that adds energy to the system in the

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 : 1. Elevation. 2. Pump Curve. 3. Operation.

Questions

Questions