The question describes a specific layout for distributing water within a populated area. Let's break down the description and compare it to the different types of water distribution systems.

Understanding the Dead End System

The described system starts with a main pipe line running through the center. From this central pipe, sub-mains take off on both sides. These sub-mains then further divide into several branch lines that supply water to different parts of the area. Crucially, in this type of system, the branch lines usually terminate at specific points and do not connect back to other parts of the network or the main line. This creates a 'dead end' for the flow in each branch.

This arrangement is characteristic of a Dead end system, also sometimes referred to as a Tree system or a simple distribution system. It's like the branching pattern of a tree, where the trunk is the main line, branches are the sub-mains, and smaller twigs are the branch lines.

Comparing Water Distribution Systems

To understand why the description fits the dead end system, let's look at the other options:

• Reticulation system: This system consists of a network of interconnected pipes forming loops. Water can reach any point from multiple directions, providing flexibility and reliability. It does not typically have a single central main with dead-end branches.
• Ring system: This is a type of reticulation system where the pipes are laid out in a closed loop around the area being served. The main supply enters the loop at one or more points.
• Radial system: In this layout, the main pipe starts from the source (like an elevated reservoir) and runs towards the area. Sub-mains then radiate outwards from this main line, supplying different zones. Branch lines extend from these sub-mains. While it involves radiating pipes, the description specifically points towards branches terminating without forming loops or extensive radial patterns from a single central line to both sides.

Why it's a Dead End System

The key features mentioned – a central main pipe line, sub-mains taking off to both sides, and subsequent division into branch lines which terminate – perfectly align with the definition of a Dead end system. The water flows in one direction from the main supply down the branches until it reaches the end.

Therefore, the described water distribution network is a Dead end system.