An-Najah National University Civil Engineering Department

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• An-Najah National UniversityCivil Engineering
  Department Analysis of the Water Distribution
  Network of howara-Nablus
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• Submitted by
• Rami Ahmad
  Mohammed Ashour
• numan mizyed
• 2010

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The importance of water distribution networks

• Distribution systems move water from the source
  to the consumer . In situations of having
  population growth, increasing demand for water
  and shrinking water sources make these systems to
  become more vital than ever before.
• The water in any distribution system may become
  contaminated if the sources were not protected
  and monitored in an appropriate manner, or
  treatment plants were not working properly, or no
  maintenance of infrastructure

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The main objectives

• Assess the water consumption in howara area.
• Analyze hydraulically the water distribution
  network of howara by using EPANET.

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Study area

• The population of howara Alshaabia
• is 8500 persons.
• The highest elevation in the area
• is 538 m and the lowest is 405 m

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Methodology

• Information and data collection
• These include the nature of the area, its
  climate, water resources ,per capita water
  consumption , statistics information and contour
  map. In addition , interviews were made with
  municipality employees, etc.
• Data preparation using GIS and Excel.
• Evaluate the network under current condition in
  terms of population size using the computer
  program (EPANET).

• Evaluate the network under the scenario obtain
  of future population increase
• State the main conclusions .

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Network Development

• The GIS file which is taken from the
• Municipal, has several layers _
• Road layer
• Nablus Contour layer ,
• Water house connection ,
• Water main connection and
• building layer .

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Preparing the map making Thiessen polygons.
Thiessen Polygons are used to predict the values
at surrounding point . Thiessen polygons have the
unique property that each polygon contains
only one input point. The Thiessen polygons are
constructed as follows At first we make an
area that limits the study area.
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By using GIS analyses tools Thiessen Polygons
were created .
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Transferring the Map to EPANET The Shp2epa
program was used to transfer the map from the GIS
to EPANET.
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Preparing the data required for the EPANET
analyze
The data required in the EPANET program is the
base demand and the elevation for the junctions
and pipe type ,length and diameter for the pipe
and need data for pump. For the base demand the
following procedure used to calculate it _ 1_By
using the GIS program, select Analysis tool
_Overlay _ Intersect. Then we use this order
between the Thiessen ID and the building area ID.
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2_from the attribute table, we find the area of
the building in every thiessen according to its
ID. 3_To know the point ID with respect to the
thiessen ID we made intersect between them. 4_the
area in the attribute table is multiplied by the
density . 5_The result is the population in every
thiessen. This number is multiplied by the water
consumption per capita which equals 80 L/c-day.
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For the elevation from the GIS file we have the
contour layer of the study area used to find the
elevation for every node by using the identify
order
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According to the coordination of the nodes, it is
transferred to the EPANET file by using the GIS,
following these steps. According to the pipe data
When the program shp2epa is used to transfer
the file to the EPANET automatically the length
of the pipe is found in the EPANET file .
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The pipe type is important to determine the
roughness coefficient by using the identify tool
in the GIS or the attribute table we find that
the pipes made of steel , by using the same way
the diameter of pipes were found . According to
the pump The pump characteristic curve ,the
data required was the flow at which the pump work
and the head corresponding to it which was (200
CMH) (380m) respectively
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Network Analyses
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The analyses in this chapter done for three
cases Existing steady state . Transient steady
state for the existing condition. Future network
analyses.
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Existing steady state . According to the pressure
there is no negative pressure , the highest
pressure was 175 m and the lowest pressure was 33
m .
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The relation between the pressure and the
elevation was inverse proportion
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According to the velocity, the results were
within the range (0.3-2) m/sec. There is no
velocity above 2 m/sec and there are some pipes
with velocity below 0.2 m/sec .
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2_Transient state in the existing condition
In this case the base demand is steady state
case ,except the time pattern. In this study ,
the pattern time step was set to 2 hours . This
will cause demands to change at 12 different
times of the day.
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In this case we have a negative pressure
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the relation between the Flow with time for Link
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the relation between the pressure and the time
for node 1.
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the relation between the velocity and the time
for link 65.
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the Pressure with time for the first node120 in
the network
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Future network_
In this case the future analysis for the existing
network after 25 years from now . In this case we
have two variables , the population and the water
consumption per capita . by using the following
equation . Pf Pp ( 1i)n The population
after 25 years 7,062 persons .
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According to WHO the future consumption range is
(100_150). To estimate the future water demand
for each node , the existing water demand will be
multiplied by a factor . In this case we will
change the roughness factor and the losses in the
network with the factor ,in three cases.
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In this case we have a negative pressure
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Recommendations
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The current velocity values of the network are in
general within the limits, some pipes will be
replaced by larger pipes
Pipe ID Previous Diameter (mm) Recommended diameter(mm)
79 50.8 76.2
7 50.8 76.2
78 76.2 101.6
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As we see there are negative pressures in the
future case , but we can solve this problem if we
replace the existing pump by another pump which
flows 320 CMH at a head 480 m .The result
becomes acceptable where the lowest pressure is
59.7m(Node 2), and the highest pressure is 201m
(node 9).  
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THE END
THANKS FOR YOUR ATTENTION