Water Distribution

Question 1

What is a rising main?

Answer 1

• A rising main is the pipe between the water treatment and storage.

Question 2

What is a virgin rising main?

Answer 2

A virgin rising main is a pipe from the water treatment to storage that has no branches coming off it.

Question 3

What is the distribution main?

Answer 3

• The pipe between the storage and service mains/ branches.
• Also used for essential services, such as fire hydrants.

Question 4

What is the preferential design for distribution mains and why?

Answer 4

The preferential design for distribution mains is network design, because:

• If one line fails, then the water can still get to other points in the network.
  
  • This also allows servicing and maintenance to take place with little disruption.

Question 5

What is a service main?

Answer 5

Pipe from distribution main to outlet point.

Question 6

Why are service mains usually smaller than other mains?

Answer 6

To limit the amount of flow, ensuring that water isn’t wasted.

Q = Av

Question 7

What are the four types of distribution system?

Answer 7

1. Gravity Direct
2. Indirect Pumping
3. Direct Puming
4. Direct - Indirect Pumping

Question 8

What is gravity direct distribution? What are it’s advantages and disadvantages?

Answer 8

When there is no pump and water is trasnported using only the head due to gravity.

Question 9

What is indirect pumping? What are it’s advantages and disadvantages?

Answer 9

Pumping to a storage tank and then distributing it to it’s target location via gravity direct method.

Question 10

What is direct pumping? What is it’s advantages and disadvantages?

Answer 10

Direct pumping is when water is pumped directly to it’s location.

Question 11

What is direct-indirect pumping? What is it’s advantages and disadvantages?

Answer 11

Pumping line goes past target location for water and up to a storage tank. If volume of water exceeds storage tank, then direct pumping can be used intermedietly.

Question 12

What are the main materials used in pipelines?

Answer 12

• Metal
• Plastic
• Concrete

Question 13

What type of plastic pipe is currently used by the MOD?

Answer 13

Medium Density Polyethelyne (MDPE)

Question 14

What are the advantages of surface laying pipe?

Answer 14

• Advantages:
  
  • Easier to install and maintain (Capex / Opex)
  • Reduced corrosion from soil
  • Easier to test and comission.
  • No clash with current buried services
  • Less equipment/ materials required to install

Question 15

What are the advantages of buried pipe?

Answer 15

• Effects of contraction / expansion reduced
• Effects of freezing reduced
• Fluid kept cool in hot climates
• Mechanical protection from damage
• No restriction to pedestrians/ vehicles