Water distribution is essential when it comes to conveying water from the source to the consumers. The system is needed to supply this water where is needed and that is what makes it very important.
There are several components included in a distribution system which include, pipe fittings, reservoirs, pumps, flow leak detectors and so many other components.
The efficiency of a water distribution system will mainly depend on its proper planning, maintenance and execution.
Types of distribution systems.
Depending on the method of distribution used, the system distributions are divided into three categories namely;
- Gravity distribution system.
- Pumping distribution system.
- Combined distribution system (dual).
1. Gravity distribution system.
From the word “gravity” this system of distribution mainly depends on gravity to distribute water from the source to its consumers.
Since it uses gravity to distribute water some measures should be taken into consideration.
For this system to work effectively the source should be from a higher ground level and the area where the water is to be supplied should be on low-level ground.
This system of water distribution is cheaper compared to pumping or the combined distribution system.
2. Pumping distribution system.
To its name, this type of distribution system uses a pump to pressurise water, so that it moves from the source to the distribution main.
This type of system doesn’t depend on gravity anymore.
The best thing about this system is that you don’t need any storage devices since the pump will be doing the work of moving this water to the distribution mains and services.
Though higher lift pumps are required to overcome friction loss at different stages and run at different speeds to meet the requirements of the water consumption at different periods.
The same pump should have some residual head at the points of distribution to be able to rise the water to storey buildings.
Since the pump doesn’t work at its maximum efficiency this makes this system uneconomical.
To add on, the pump should be regularly inspected and maintained since the whole system depends on it.
This means that the maintenance and repair costs of this system will go high.
The main advantage of this system is that the additional cost of building a storage facility will be saved and it also can supply a very large quantity of water when needed to.
Since the system depends on the pump to pressurize the water and move it from the source to the distribution main, there should be a backup plan in case there is a power failure.
You will have to buy generators and keep them as a backup power plan in case the whole area goes black.
This system is very effective for small areas.
3. Combined distribution system (dual system).
This type of distribution system depends on gravity and pumping and hence the name combined.
The treated water is pumped from the source and stored in a higher ground storage facility (tank or a reservoir). And from these tanks that are highly elevated the water is fed into the distribution system by the action of gravity.
The pump should work constantly to ensure enough level of water is maintained in the distribution tanks.
If there is a higher water demand, there will be the addition of the storage facility since the system can’t convey a large quantity of water as gravity is used to distribute the water from the tanks.
The main advantage of this system is that there is no interruption of water supply even when there is a repair of the pump and also it improves the water quality since the water is stored for some time at the storage facility before it reaches the consumers.
This type of system is suitable for all areas hence it’s accepted universally.
Small pumps can be introduced if the supply elevation is lower.
Requirements of the water distribution system;
1. The system should distribute water with the same degree of purity.
This is the first requirement of the system, it should ensure that the water distributed to the customers has the same degree of purity.
The system should be able to distribute water without interfering with its purity.
If this condition can’t be met by the distribution system then it’s not fit for use as it will affect the consumers’ health.
2. The system should be economical, and easy to maintain and operate.
When designing a water distribution system you should ensure that it’s economical.
The system has to be affordable, in case there is damage it can be repaired easily without any issues.
Also, it should not be too complicated to maintain and operate.
As these are very important criteria that will enable the effective use of that system.
For the system to work effectively regular maintenance should be able to be carried out, if the system is harder to maintain, will it be effective for use?
The ease of operation should be one of the key factors when designing a water distribution system.
This is what will make it easier for anyone to use that system in case the main operators are not available.
3. The diameter of the pipe design should meet the fire demands.
This is another important requirement for the water distribution system.
Fire accidents do happen from time to time, when that happens then there will be a higher demand for water from the distribution system.
If the water distribution system can’t meet the fire demands then it will be hard to take care of such an accident.
And the system will not be fit for use. So the system pipes’ diameter should be designed in a way to meet the fire demands need so that it can be used in case of fires.
4. The system should be safe from any future pollution.
If the system is not safe from any future and current pollution then it’s not safe for use.
It will risk the lives of consumers.
For this to happen the water distribution should be placed in areas with no pollution or any possible future pollution.
If the area where the distribution system is to be placed is used for sewers then it should not be laid there even if the sewers are completely secured.
You never know, in future the sewers pipes may burst and this will cause pollution that will endanger the lives of the consumers.
The water distribution system should be laid in an area where there are no harmful activities that will temper the purity of water.
5. The water should be supplied without interruption.
The water distribution system should ensure that there is no interruption of the water supply even when there is a repair going on.
This means if you are using a pump to supply water to the consumers you should have a generator as a backup power plan that will keep the water supply going even when there is a power failure.
If the system will bring any interruption of water supply then it’s likely to cause a lot of problems for the consumers.
The system should ensure that water is supplied throughout when it’s needed.
So, every measure should be put in place to ensure this happens.
6. The system should meet maximum hourly demand.
If the water distribution system can’t meet the supply demands of the consumers then it’s useless.
It’s not fit for use because it will bring so many shortages during its supply.
When designing the water distribution system this is something that should be kept into consideration.
If the system can’t meet the hourly demands of the consumers then it’s not effective at all.
The main purpose of a water distribution system is to ensure that water is supplied to meet the demands of the consumers, if the system doesn’t solve that then it’s not efficient.
Water distribution methods (layouts)
Since water is needed to be supplied to the consumers, the pipes should be laid out in a certain layout so that it meets the needs of the consumers.
As the distribution system contains the mains, sub-mains, branches, and lateral and service connections, a certain layout is needed to achieve an effective supply of water.
So, the pipes will need to be laid out in a certain way that matches the area where the water is to be supplied.
This condition forced the need for certain layouts that will help in the distribution of this water to consumers without interfering with the town layout.
There are four methods of water distribution methods namely;
- Dead end or tree distribution system.
- Radial distribution system.
- Ring or circular distribution system.
- Grid or reticular system.
1. Dead end or tree distribution system.
This distribution system is also known as the tree distribution system because its pipe is laid out in a tree structure.
It contains mains, branches, sub-mains and cut-off valves.
The system has one main pipe that comes from the mains, from which other pipes (sub-mains) bifurcate and from it comes out the branches called lateral.
These branches are the ones that are connected to consumer services.
This type of system distribution is used in areas where the building is unplanned.
The extensions of the pipes will go as per the need of the consumers.
This system is very easy to design since it doesn’t need any structure for it to work.
The disadvantages of this system are;
The flow of water is through one pipe, so in case there is damage to a certain area there will be a shortage of water.
It has many dead-ends thus there are no free circulations of water in the system which means stagnant water has to be removed periodically and this is water wastage.
2. Radial distribution system.
This system of distribution is different from the dead-end system since it has a certain structure that it follows.
It has a main pipe which supplies water and the sub-mains bifurcate from it.
It has a big area that is divided into zones and at the centre of each zone, there is a distribution reservoir.
The main function of these reservoirs is to receive water from the sub-mains and transports the water to the consumers using the branches (laterals).
Let me give you a summary of how it works; the main pipe contains water to be conveyed to the consumer, the sub-mains pipe bifurcates from the main and takes water to the distribution reservoir located at the centre of each zone and the branches take water from the distribution zone to the consumers.
3. Ring or circular distribution system.
The ring distribution system can be in a circular, rectangular or square shape structure.
This system has a main pipe that runs around the area that is supposed to be supplied with water.
From the main pipe, there are cutoff valves employed which are then connected to the sub-mains. The sub-mains and branches run perpendicularly to the mains.
The lateral will bifurcate from the sub-mains and it will serve water to the areas needed.
The function of the cutoff valves in this system is to terminate the water supply to a certain channel whenever there is a repair going on.
This is to prevent the whole area from experiencing water shortages when there is a repair going on at a certain channel.
This system is used in a planned town.
4. Grid or reticular distribution system.
This system is also known as an interlaced system. It can be a rectangular or square shape.
It contains the main pipe that contains water to be transported and conveyed through a central channel. As usual, the sub-mains bifurcate from it from each side of the main pipe (left and right).
The sub-mains will branch to the lateral which will be used to supply water to the consumers.
The main components of these systems are;
- Mains.
- Sub-mains.
- Branches (lateral).
- Scour valve.
This distribution layout is also used in planned towns.
If you have any questions regarding the water distribution system leave your comment.
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