Civil war Day 20-PWD-Water distribution system

For unplanned haphazard developed city or old cities developed in an irregular manner, the water distribution lines are laid in

• Radial system
• Grid iron system
• Dead end system
• Ring system

Answer explanation

The dead end system (also known as the tree system) is used in old or irregularly developed areas, where streets do not follow a definite pattern.

Gate valves are also known as?

• Non return valve
• Air inlet valve
• Safety valves
• Sluice valves

Answer explanation

Gate valves are commonly called sluice valves, as they control the flow of liquid by lifting or lowering a gate inside the valve body.

Select the correct statement related to water distribution pipe systems?

• Drain valves are provided at all the low points
• Drain valves are provided at all the high points
• Sluice valves are provided only once, at the start of pipe system
• Air valves are provided at all the low points

Answer explanation

Drain valves are installed at all low points to remove accumulated water during maintenance or shutdown. Air valves, on the other hand, are placed at high points to release trapped air.

Name the valve which prevents back-flow of water:

• Gate valve
• Globe valve
• Check valve
• Flushing valve

Answer explanation

A check valve (or non-return valve) allows water to flow in only one direction, thus preventing back-flow in the pipeline.

The major disadvantage of intermittent system of supply of water is

• Bigger pipes and pumps required
• More number of valves required
• Consumers should store water
• Infiltration of impurities may occur through leaky joints

Answer explanation

In an intermittent water supply system, pressure drops during non-supply hours, allowing impurities to enter through leaky joints, which poses serious health risks.

The type of valve which is provided on the suction pipe in a tube well is

• Air relief valve
• Reflux valve
• Pressure relief valve
• Sluice valve

Answer explanation

A reflux valve (also known as a foot valve) is installed on the suction pipe of a tube well to prevent the return flow of water, maintaining priming in the pump.

System of layout of distribution pipe, where there is one main supply from which a number of sub-mains originates:

• Tree system
• Interlaced system
• Ring system
• Radial system

Answer explanation

The tree system (also called the dead-end system) consists of one main supply pipe from which several sub-mains and branches originate — suitable for unplanned or small towns.

Open impeller type of centrifugal pumps are largely used for pumping water supplies, because:

• their efficiency is high
• they do not clog easily
• both a and b above
• none of them

Answer explanation

Open impeller pumps are suitable for pumping water with suspended impurities because they do not clog easily, though their efficiency is slightly lower compared to closed impellers.

The chances of contamination of water is less in which of the following

• Continuous system
• Intermittent system
• Combined system
• Dead end system

Answer explanation

In a continuous water supply system, water remains under pressure at all times, preventing entry of contaminants through leaky joints — unlike intermittent systems.

The suitable layout for a water supply distribution system, for a city of roads of rectangular pattern, is

• Dead end system
• Grid iron system
• Tree system
• Radial system

Answer explanation

The grid iron system is ideal for cities with a rectangular road pattern, ensuring uniform pressure and continuous water supply through interconnected mains.