Page 35 - Water Engineering Hydraulics, Distribution and Treatment

Useful
Useful
storage
Supporting
storage
Inlet and storage 1.9 Distribution Works 13
Overflow outlet Inlet and Drain
Drain outlet
(a) Standpipe (b) Elevated tank

Original surface Original surface
Figure 1.7 Four types of service, or
(c) Open service reservoir (d) Covered service reservoir distribution, reservoirs.

Hydraulically, the gridiron system has the advantage of
delivering water to any spot from more than one direction and
of avoiding dead ends. Gridiron systems are strengthened by
substituting for a central feeder a loop or belt of feeders that
supplies water to the congested,or high-value, district from at
least two directions. This more or less doubles the delivery of
the grid. In large systems feeders are constructed as pressure
tunnels, pressure aqueducts, steel pipes, or reinforced con-
crete pipes. In smaller communities the entire distribution
system may consist of CIPs. Cast iron is, indeed, the most
common material for water mains, but asbestos-cement, in
general, and plastics, in the case of small supplies, are also
important.

Feeder
Branch
Gridiron

Feeder

(a) Branching pattern (b) Gridiron pattern with
with dead ends looped feeder
Figure 1.8 A pipeline in the Goldfields Water Supply Scheme,
High value district is crosshatched
Perth, Australia (Source: http://en.wikipedia.org/wiki/Image
:Goldfields_Pipeline_SMC.JPG). Figure 1.9 Patterns of water distribution systems.