Distribution of Water
Prof S S Jahagirdar
• Water distribution systems, method of
distributing water, system configuration,
appurtenances, basic system requirements,
hydraulic analysis head balance method,
quantity balance method, equivalent pipe
concept, Newton – Raphson and linear
Requirements of Good
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
3.It should be capable of supplying the
requisite amount of water during fire
4. The layout should be such that no
consumer would be without water supply,
during the repair of any section of the
5.All the distribution pipes should be
preferably laid one meter away or above
the sewer lines.
6.It should be fairly water-tight as to keep
losses due to leakage to the minimum.
Classification of distribution
• Depending on topography of town
water may be distributed by
3. Combination of pumping and
1. Pumping system
• The treated water is directly pumped into a
distribution main without storing at high
• High lift pumps are provided.
• Pumps are required to be operated at
variable speed because of fluctuating
• Continuous attendance is required to
regulate the pump.
• Additional pumps are provided as standby.
• Due to load shading water supply may get
• In such case pumps are operated by using
2. Gravity system
• Gravity force is used to distribute water
from ESRs to users.
• Pumping is eliminated
• For proper working sufficient head should
• In case of fires water is to be pumped by
using pumps into distribution system
3. Combination of pumping and
• Water after treatment is pumped to ESRs and
supplied to users under gravity.
• To fill the ESRs pumps can be operated at constant
• This reduces wear and tear of pumps and reduces
• Special supervision is not required.
• Fire demand is satisfies efficiently.
• Water is available in case of load shading or failure of
Layouts of Distribution Network
Dead End System
Grid Iron System
2.Simple, economical and can be
extended according to growth
3.No. of valves are less
4.Determination of discharges and
pressure easier due to less number
1.Due to many dead ends, stagnation
of water occurs in pipes.
2.Particular area is affected in case of
3.System fails in maintaining
satisfactory pressure at remote parts.
4.Discharge available for fire fighting
will be limited.
5.Large no. of scour valves are
required and periodically need to be
2. Grid Iron or Reticulation
It is suitable for cities with rectangular
layout, where the water mains and
branches are laid in rectangles.
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
3. Enough water is available in the streets for
4. No stagnation of water as there is free
circulation of water in the system
1. Large no of cutoff valves are provided.
2. Exact calculation of sizes of pipes is not
possible due to provision of valves on all
3. Analysis of distribution network is difficult
and time consuming.
4. Cost of laying water pipes is more
3. Ring or Circular System:
• 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.
• Can be used for well developed and
well planned cities.
• Possesses same advantages and
disadvantages of grid iron system.
• For fire fighting large quantity of water
4. 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.
1. It gives quick service.
2. Calculation of pipe sizes is easy.
3. Head loss is less
Q1. Explain following types of layouts of distribution
system with sketch
i. Dead end system
ii. Grid iron system
iii. Radial system
iv. Ring system
Q2. Discuss types of distribution system