Water supply and distribution system

Providing sufficient water of appropriate quality and quantity has been one of the most important component. Ancient civilizations were initiated near water sources. The challenge to meet user demands also increased with rise in the population.

People began to transport water from other reliable locations to their communities. For example, the Romans constructed aqueducts to deliver water from distant sources to their communities.

Today, a water supply system consists of infrastructure that collects, treats, stores, and distributes water between water sources and consumers. Limited new natural water sources, especially in the places where water is deficit and rapidly increasing population has led to the need for innovative methods to manage a water supply system. For example, reclaimed water has become an essential water resource for potable and nonpotable uses. Structural system additions including new conveyance systems and treatment and recharge facilities and operation decisions, such as allocating flow and implementing conservation practices, are made with the present and future demands in minds. As additional components and linkages between sources and users are developed, the complexity of the water supply system and the difficulty in understanding how the system will react to changes grows.

Many efforts on the development of a water supply system have been made through for sustainable water supply. However, the complexity of system limited the site specific application at the first era. As water demand pressures raise increasingly on the existing water supply system, many studies attempted to develop a general water supply system to assist decision makers to design more reliable systems for a long range operation period. These attempts also include the optimization of total system construction and operation cost. Under given situations such as pipeline maintenance, non-revenue water, advanced metering infrastructure, the ultimate goal of this paper is to ensure water distribution system challenges are overcome and   supply water sources to users reliably in a more sustainable and timely manner as a long-term plan.

Water Distribution Systems

The purpose of distribution system is to deliver water to the end users with appropriate quality, quantity and pressure. Distribution system is used to describe collectively the facilities used to supply water from its source to the point of usage.

Requirements of Good Distribution System

  1. Water quality should not get deteriorated in the distribution pipes.
  2. It should be capable of supplying water at all the intended places with sufficient pressure head.
  3. It should be capable of supplying the requisite amount of water during firefighting.
  4. The layout should be such that no consumer would be without water supply, during the repair of any section of the system.
  5. All the distribution pipes should be preferably laid one metre away or above the sewer lines.
  6. It should be fairly water-tight as to keep losses due to leakage to the minimum.

Layouts of Distribution Network

The distribution pipes are generally laid below the road pavements, and as such their layouts generally follow the layouts of roads. There are, in general, four different types of pipe networks; any one of which either singly or in combinations, can be used for a particular place. They are: Grid, Ring, Radial and Dead End System.

Grid Iron System:

It is suitable for cities with rectangular layout, where the water mains and branches are laid in rectangles.

Advantages:

  1. Water is kept in good circulation due to the absence of dead ends.
  2. In the cases of a breakdown in some section, water is available from some other direction.

Disadvantages

  1. Exact calculation of sizes of pipes is not possible due to provision of valves on all branches.

Ring System/Loop:

The supply main is laid all along the peripheral roads and sub mains branch out from the mains. Thus, this system also follows the grid iron system with the flow pattern similar in character to that of dead end system. So, determination of the size of pipes is easy.

Advantages:

  1. Water can be supplied to any point from at least two directions.

Radial System:

The area is divided into different zones. The water is pumped into the distribution reservoir kept in the middle of each zone and the supply pipes are laid radially ending towards the periphery.

Advantages:

  1. It gives quick service.
  2. Calculation of pipe sizes is easy.

Dead End System:

It is suitable for old towns and cities having no definite pattern of roads.

Advantages:

  1. Relatively cheap.
  2. Determination of discharges and pressure easier due to less number of valves.

Disadvantages

  1. Due to many dead ends, stagnation of water occurs in pipes.