General Description

Water-distribution systems that serve populated areas and industrial complexes, including offices and light and heavy industry, are classified broadly as being of the loop, gridiron, or tree types. Figure C1.1 describes these three types. Within the broad concept, there may be a combining of all three types used as the building blocks for the overall system.

FIGURE C1.1: ( a) Loop system, ( b) grid system, ( c) tree system.

In the loop system, large feeder mains that surround areas many city blocks square serve smaller cross-feed lines connected at each end into the main loop. See Fig. C1.1a.

In the gridiron (or grid) system, the piping is laid out in checkerboard fashion, with piping usually decreasing in size as the distance increases from the source of supply. See Fig. C1.1b.

In the tree system, there is a single trunk main, reducing in size with increasing distance from its source of supply; branch lines are supplied from the trunk. See Fig. C1.1c.

The grid and loop systems provide better reliability because of their multiple paths. Grid and loop systems are often backed up with feeder pipes leading directly from the pumping station to remote distribution centers serving to bolster the supply to meet increased demands with growth of population.

Water distribution systems are made...