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Water Distribution and Transmission Systems
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Water Distribution and Transmission Systems
Water Distribution and Transmission Systems
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1
Question
What is the recommendation for establishing Level II distribution and transmission systems?
Answer
These should already be designed to allow future expansion and eventual upgrading to a higher level of service.
2
Question
What needs to be considered in the design of rural water systems?
Answer
The nature of operation.
3
Question
List the methods of water transmission distribution.
Answer
1. Gravity Flow 2. Pumping with Storage 3. Direct Pumping to the Distribution System.
4
Question
How is water transported using Gravity Flow method?
Answer
Water is pumped to a storage tank first, then distributed by gravity from the tank to the consumers.
5
Question
What is the unit of pressure in the English System?
Answer
lbin2 or psi.
6
Question
What is the unit of pressure in the SI System?
Answer
Pa or kPa.
7
Question
How does pressure change with the depth of water?
Answer
Pressure increases linearly with the depth of water.
8
Question
What is pressure head?
Answer
The pressure exerted by a column of water.
9
Question
What is the specific weight of water?
Answer
62.4 lbft3.
10
Question
What is the conversion factor for psi to pressure head in the English System?
Answer
1 psi = 2.31 ft pressure head.
11
Question
What is the conversion factor for kPa to pressure head in the SI System?
Answer
1 kPa = 0.102 m pressure head.
12
Question
Name three formulas for head loss in pipeline hydraulics.
Answer
1. Darcy-Weisbach formula 2. Hazen-Williams formula 3. Mannings formula.
13
Question
What does the C-Value represent in pipeline hydraulics?
Answer
A carrying capacity factor that is sometimes referred to as the roughness coefficient, which varies depending on the pipe material.
14
Question
What is a contributing component of total head loss in a pipeline?
Answer
Head loss from turbulence due to pipe fittings and appurtenances, sometimes called minor losses.
15
Question
What is the Hydraulic Grade Line (HGL)?
Answer
The height that water will rise vertically in a tube attached to the pipe that is open to the atmosphere.
16
Question
What is the function of a transmission system in water supply?
Answer
To transport water from the source to the reservoir and then to the distribution point.
17
Question
What are water conduits for the transmission system?
Answer
Canals, aqueducts, tunnels, free-flow pipelines, and pressure pipelines.
18
Question
What is the recommended procedure for analyzing HGL in transmission systems?
Answer
Routing alongside roads or public ways is preferred for easier inspection and ready access for maintenance and repair.
19
Question
What should the HGL for the maximum possible flow rate for the main lie above?
Answer
The pipeline through the entire length of the transmission system.
20
Question
What is the general guideline for computing the transmission pipe size?
Answer
The main should have at least the carrying capacity to supply water at a rate equivalent to the maximum day demand.
21
Question
For direct pumping to the distribution system with no reservoir, how is the transmission main designed?
Answer
For a maximum carrying capacity equivalent to the peak hour demand.
22
Question
What is the maximum pressure recommended for the transmission line design?
Answer
The maximum computed HGL should not be over the allowable maximum pressure of the line, which is 70 m head.
23
Question
What are the two types of distribution systems mentioned?
Answer
1. Branched System 2. Looped System.
24
Question
What is a Branched System in water distribution?
Answer
Also referred to as a Dead-end System, where the size of the main line decreases as its distance from the source increases.
25
Question
What is a Looped System in water distribution?
Answer
A distribution network where there are few or no pipe dead-ends, allowing water to move freely through the system.
26
Question
What is the advantage of a looped system?
Answer
1. Lower water velocities in the main, reducing head losses. 2. Main breaks can be isolated, minimizing service interruptions. 3. Usually better chlorine residual content.
27
Question
What is the primary purpose of isolation valves in a water distribution system?
Answer
To provide means of turning off a portion of the system.
28
Question
What types of valves are included in isolation valves?
Answer
Gate valves, butterfly valves, globe valves, and plug valves.
29
Question
What does the conservation of mass principle state in pipe network analysis?
Answer
The fluid mass entering any pipe system will be equal to the mass leaving the system.
30
Question
What is the Bernoulli principle in hydraulic network analysis?
Answer
In any closed path or circuit, the algebraic sum of the energy head losses in the individual pipes is zero.