Distribution of Water MCQ Quiz - Objective Question with Answer for Distribution of Water - Download Free PDF

Explanation

Dead-end System:

• It is also called a tree system, it consists of one main supply line, from which originates (generally at right angles) a number of sub-main pipes; Each sub-main is then divided into several branch pipes, called laterals
• This type of distribution system is suitable for older towns that have developed in a haphazard manner, without properly planned roads e.g. old cities, irregularly grown cities, etc; It is economical and simple

​

Gridiron System:

• It is also known as an interlaced system or reticulation system, the mains, sub-mains, and branches are all connected with each other
• There is no dead-end in the system as looping is provided and is most suitable for well-planned cities.
• There is equal pressure in all pipes and multiple flow path.

Radial system:

• If a city or town is having a system of radial roads emerging from different centers, the pipeline can be best laid in a radial method by placing the distribution reservoir at these centers
• The water from the distribution reservoir is then supplied radially to distribution pipes and thus also known as zonal distribution

Ring System:

• It is also called a circular system; In this system, a closed ring, either circular or rectangular, of the main pipes, is formed around the area to be served.
• The distribution area is divided into rectangular or circular blocks, and the main water pipes are laid on the periphery of the blocks
• This system is very suitable for towns and cities having well-planned roads.
• It is economical and the pressure at the ends are reasonably equal

Explanation:

Valve Types for Pipeline Flow Control

In pipelines, different types of valves are used to control the flow of water. Each valve type has its own advantages and applications, especially when it comes to manual operation and quick opening/closing. Below is an analysis of the given options to determine the most suitable valve for the specified criteria:

1. Globe Valve

   • Globe valves are generally used for throttling applications, where precise control of flow is required. They are not typically known for quick opening and closing.

   • They have a complex structure that makes them less convenient for manual operation when quick action is needed.

2. Gate Valve

   • Gate valves are designed for on/off control, providing a straight-line flow of fluid with minimal restriction. They are suitable for full open or full close applications.

   • While they can be manually operated, their opening and closing process is slower due to the need to raise or lower the gate.

3. Butterfly Valve

   • Butterfly valves are characterized by their quick operation, as they rotate a quarter turn (90 degrees) to open or close. This makes them highly suitable for applications where quick opening and closing are required.

   • They are also more convenient for manual operation compared to other types due to their simple and compact design.

4. Check Valve

   • Check valves are primarily used to prevent backflow in pipelines. They operate automatically, not manually, and are not suitable for controlling flow in the same manner as globe, gate, or butterfly valves.

Conclusion

Based on the analysis, the most suitable valve for convenience in manually closing the pipes to control the flow of water and having the advantage of quicker opening is: Butterfly Valve.

Explanation:

1. Resting on Ground Water Tank: These tanks are widely used for clear water reservoirs and settling tanks in water treatment plants. They are typically constructed at ground level to store treated water (clear water) after filtration or sedimentation. Resting on ground tanks are easier to access for maintenance and cleaning, which makes them suitable for clear water storage. They provide stability and are cost-effective for larger storage capacities.

2. Under Ground Water Tank: Although underground tanks are used for certain applications, their use for clear water reservoirs and settling tanks is less common compared to ground-level tanks. Underground tanks are more challenging to maintain and inspect regularly, making them less suitable for treated water storage where regular monitoring is required.

3. Elevated Water Tank: These are primarily used for water distribution by providing pressure through gravity. They are not typically used for clear water reservoirs or settling tanks.

4. Circular Water Tank: While circular tanks are a common shape for water tanks due to their efficient pressure distribution, this option does not specifically denote their usage type. Ground-level tanks can be circular in shape but are distinguished by their placement rather than shape.

Explanation:

Dead-end System (Tree system):

• It is also called a tree system, it consists of one main supply line, from which originates (generally at right angles) a number of sub-main pipes; Each sub-main is then divided into several branch pipes, called laterals
• This type of distribution system is suitable for older towns that have developed in a haphazard manner, without properly planned roads e.g. old city, irregularly grown city, etc. It is economical and simple

Grid iron System:

• It is also known as an interlaced system or reticulation system, the mains, sub-mains, and branches are all connected with each other
• There is no dead-end in the system as looping is provided and is most suitable for well-planned cities; There is equal pressure in all pipe and multiple flow path

Radical system:

• If a city or town is having a system of radial roads emerging from different centres, the pipeline can be best laid in a radial method by placing the distribution reservoir at these centres
• The water from the distribution reservoir is then supplied radially to distribution pipes and thus also known as zonal distribution

Ring System:

• It is also called a circular system; In this system, a closed ring, either circular or rectangular, of the main pipes, is formed around the area to be served
• The distribution area is divided into rectangular or circular blocks, and the main water pipes are laid on the periphery of the blocks
• This system is very suitable for towns and cities having well-planned roads
• It is economical and pressure at the ends are reasonably equal

Concepts:

Altitude valves are installed in the supply line to elevated tanks, basins, or reservoirs.   

The purpose of this valve is to admit water into the elevated tank until a present level is reached and to close at that point to prevent overflow and also holding the reservoir/elevated tank level constant.

Additional Information

The other different type of valves and their uses is given below:

Explanation:

IS 1172: 1993 is used for the basic requirements for water supply, drainage and sanitation

Important Points IS 456: 2000 - PLAIN AND REINFORCED CONCRETE - CODE OF PRACTICE 

IS 1035 (Part 32): Methods of Sampling and Test (Physical & Chemical) for water and wastewater

IS 10500 (2012): DRINKING WATER - SPECIFICATION

Additional InformationFrom IS 1172 (1993):

The following rates per capita per day may be considered the minimum for domestic and non-domestic needs:

1. For communities with a population of up to 20,000 and without a flushing system : 

a) water supply through standpost: 40 lpcd ( Min ) 

b) water supply through house service connection:  70 to 100 lpcd 

2. For communities with a population of 20,000 to 100,000 together with a full flushing system: 100 to 150 lpcd 

3. For communities with a population above 100000  together with a full flushing system: 150 to 200 lpcd

Concept:-

Equivalent Method: - This method is used to convert the entire distribution system of pipes to equivalent pipe, which carries the discharge corresponding to the same head loss.

Hardy-Cross Method: - This method is used to find the discharges in the unknown pipes using the equation of continuity. It only calculates discharges and the method remains the same whether domestic supply or fire demand considered or not.

Electrical Analysis: - This method establishes the analogy between the flow of fluid and the flow of current. As per the electrical analysis, the greater is the resistance lesser will be the flow. Similarly, the greater the head loss, the lesser will be the flow of fluid.

Circle Method:- This method is used for the analysis of the distribution system in which domestic supply is neglected and fire demand is considered.

Concepts:

The various IS codes nos and their usage are specified below in tabulated form:

Explanation:

Grid Iron System:

• It is suitable for cities with rectangular layout, where the water mains and branches are laid in rectangles.
• This system is also known as an interlaced system or reticulation system. 

• In this system, the mains, sub-mains, and branches are inter-connected with each other. Thus, this system provides free circulation of water through the pipelines.

• Cut-off valves are provided at each junction point. This is suitable for well-planned towns and cities.

​

The advantages of the gridiron system are:

• In case of repairs, a very small portion of the distribution area will be affected.  
• This system provides free circulation of water through the pipelines. Hence, it is not liable for pollution due to the stagnation of water.  
• The head loss is minimum.
• It provides sufficient supply during fire fighting.

​Disadvantages of gridiron system are:

• This system requires more length of pipelines and a greater number of cut-off valves.
• Its construction is costlier.
• The design calculations are complicated and difficult.

Explanation

Dead-end System:

• It is also called a tree system, it consists of one main supply line, from which originates (generally at right angles) a number of sub-main pipes; Each sub-main is then divided into several branch pipes, called laterals
• This type of distribution system is suitable for older towns that have developed in a haphazard manner, without properly planned roads e.g. old cities, irregularly grown cities, etc; It is economical and simple

​

Gridiron System:

• It is also known as an interlaced system or reticulation system, the mains, sub-mains, and branches are all connected with each other
• There is no dead-end in the system as looping is provided and is most suitable for well-planned cities.
• There is equal pressure in all pipes and multiple flow path.

Radial system:

• If a city or town is having a system of radial roads emerging from different centers, the pipeline can be best laid in a radial method by placing the distribution reservoir at these centers
• The water from the distribution reservoir is then supplied radially to distribution pipes and thus also known as zonal distribution

Ring System:

• It is also called a circular system; In this system, a closed ring, either circular or rectangular, of the main pipes, is formed around the area to be served.
• The distribution area is divided into rectangular or circular blocks, and the main water pipes are laid on the periphery of the blocks
• This system is very suitable for towns and cities having well-planned roads.
• It is economical and the pressure at the ends are reasonably equal

Explanation:

As per IS-10500: 2012

Permissible limit in absence of alternate sources (i.e. cause for rejection) for chlorides and sulphates are 1000 ppm and 400 ppm respectively.

Additional Information

The permissible limits of various compounds are as follows:

Concept:-

The House Water Connection:

To get water supply from municipalities connection consists of the following –

1. Ferrule:

• A ferrule is a right angled sleeve made of brass or gun metal and is joined to a hole drilled in the water main to which it is screwed down with a plug.

2. Goose Neck:

• Goose neck is a small sized curved pipe made up of flexible material and is about 75cm in length forming a flexible connection between the water main and the service pipe.

3. Service Pipe:

• It is a galvanised iron pipe of size less than 50mm dia. It should be laid in under ground in a trench in which no sewage or drainage pipe is laid. The service pipe which supplies water to building through the municipal mains is connected to the main through goose neck and ferrule.

4. Stop Cock:

• The stop cock is provided before the water enters the water meter in the house. It is placed in a suitable masonry chamber with a removable cover and is fixed in the street close to the boundary wall in an accessible station.

5. Water Meter:

• It measures and records quantity of water consumed in the house.

Explanation

Dead-end System:

• It is also called a tree system, it consists of one main supply line, from which originates (generally at right angles) a number of sub-main pipes; Each sub-main is then divided into several branch pipes, called laterals
• This type of distribution system is suitable for older towns that have developed in a haphazard manner, without properly planned roads e.g. old cities, irregularly grown cities, etc; It is economical and simple

​

Gridiron System:

• It is also known as an interlaced system or reticulation system, the mains, sub-mains, and branches are all connected with each other
• There is no dead-end in the system as looping is provided and is most suitable for well-planned cities.
• There is equal pressure in all pipes and multiple flow path.

Radial system:

• If a city or town is having a system of radial roads emerging from different centers, the pipeline can be best laid in a radial method by placing the distribution reservoir at these centers
• The water from the distribution reservoir is then supplied radially to distribution pipes and thus also known as zonal distribution

Ring System:

• It is also called a circular system; In this system, a closed ring, either circular or rectangular, of the main pipes, is formed around the area to be served.
• The distribution area is divided into rectangular or circular blocks, and the main water pipes are laid on the periphery of the blocks
• This system is very suitable for towns and cities having well-planned roads.
• It is economical and the pressure at the ends are reasonably equal

Explanation:

Check valve:

(i) These valves are also known as non-return valve or reflux valves.

(ii) They allow the water to flow in one direction only.

(iii) They may be installed on the delivery side of the pumping set so as to prevent the back flow of stored or pumped water, when the pump is stopped.

(iv) When the pump is operated, the valve is opened, but when the pump is suddenly stopped the valve is automatically closed. This prevent bckword flow of water to the pump.

Additional Information

Gate valve or Sluice valve:

(i) These valves are used to regulate the flow of water through the pies.

(ii) They are generally located along the large pipe line at intervals of about 3 to 5 km to divide the pipe into different sections.

(iii) These valves are placed at the summits of the pressure conduits. 

Scour valve or Blow off valve or Drain valve:

(i) These valves are also known as wash-out valves.

(ii) To remove the entire water from pipe after closing the supply, small gate valves are provided at low point.

(iii) These valves, are necessary at low level points for completely emptying the pipe for inspection, repair etc.

Butterfly valve:

(i) They are used to regulate and stop the flow especially in large size conduits.

(ii) They are cheaper than sluice valve for larger sizes and occupy less space.

(iii) They involve slightly higher head loss than sluice valves and also are not suitable for continues throttling.