الفهرس 
CHAPTER 1: IntroductionOnly 14 pages are availabe for public view
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Abstract
Water distribution systems are designed to deliver water from a source in the
required quantity, quality and at satisfactory pressure to individual consumers in
a utility’s service area. Computer models have been built for the simulation of
water distribution systems since the mid-1960s. However, a model needs to be
calibrated before it can be used for analysis and operational study of a real
system. To meet the water supply requirement in a growing community, system
optimization method needs to be identified to satisfy an objective function
defined by the designer.
In this thesis the model for Tanta city’s network was carried out. Tanta city’s
network contains 588 pipes. The total length of pipes after skeletonization was
105,523m made from four materials Cast Iron, Asbestos Cement, Ductile Iron
and Polyvinylchloride. The network serves 322,703 capita at the end of year
2011. The water pumped into the network through three surface water stations
produce 45,790 m3/day and eight ground stations produce 113,720 m3/day.
The model has been calibrated through three types of field readings which were
static pressure, fire flow tests and extended period readings. Two cases of study
have been taken. The first case took C-factor for them equal to 53 and the second
case reduced the diameters of AC pipes by 0.92 and took C-factor equal to 67.
The results for static pressure readings and extended period readings were close
for the two cases. This values of low C-factor was for deteriorations happened to
the AC pipes as its age exceeds 50 years.
Case 1 gave more accurate results in fire flow tests readings and gave an average
absolute pressure DROP due to open hydrants difference between measured and
simulated results equals 0.969 psi and Case 2 gave an average absolute pressure
DROP due to open hydrants difference between measured and simulated results
equals 1.9875 psi. With maximum absolute pressure DROP difference equals 1.9
Optimal Design of
Water Distribution Network
(ii)
psi for case 1 and 9.2 psi for case 2 so that case 1 has been taken for the rest of
the thesis.
Calibration of residual chlorine has been done on the network after hydraulic
calibration. A calibration process has been done to gain the value of wall
reaction (kw) which made the model results close enough to the field readings to
check if the water in the network kept an adequate concentration of residual
chlorine enough for ensuring disinfection requirements through transportation.
After calibration, optimal design has been determined for the model through
defining an objective function of minimum cost design satisfying all constraints
entered to the program. This objective function has been applied at the current
situation (2012) and the future situation (2022).
Two scenarios were studied at two years 2012 and 2022. In scenario one, the
water supply stations consisted of two large surface water treatment stations and
one compact station beside eight ground water stations. On the other hand, the
operational system in scenario two consisted of three large surface water stations
only.
The optimal design was applied for scenario one only. Then, effect of the
previous optimal design on scenario two was evaluated where the two scenarios
were suggested to work as standby to each other.
The optimal design to scenario one (2012) improved the pressure over all the
network as the average pressure increase (Pavg.) changed from 11.35 psi to 17.4
psi with minimum costs 2,709,306 EGP will be carried out by changing pipes
length by 12,782m (12.1% of total length of the network) and 7.83% of total
capacity of the network. where optimal design to scenario one (2022) gave the
average pressure increase equal 14.26 psi with minimum costs 4,010,317 EGP
will be carried out by new pipes length added to the network is 637m and
changing pipes length 4,381m (4.15% of total length of the network) and 5.69%
of total capacity of the network. Then the effect of the optimal design on water
age and residual chlorine was carried out at 2012 and 2022.
The optimal design to scenario 1 was applied on the operational system of
scenario 2. The least junction pressure at maximum loading demand achieved
Optimal Design of
Water Distribution Network.