ME 404 FALL TERM PROJECT DR. DING
Water Supply System –
Hydraulic Analysis
Group E
Jaykumar Patel, Joe Rausch, Kofi Frimpong, Trey Read
11/29/2011
Project Description
Water distribution networks use pipes, storage facilities, pumps, and other components in order
to provide a water supply for many different end uses. Systems of this type are used across the world to
ensure that residences and businesses have enough water supply to meet their required demand. This
engineering project requires that a water distribution network be designed and optimized to meet the
conditions present in four separate tasks, while being mindful of the cost of the system. Each task
called out in the project provides a new set of requirements to which the system must conform. The
network layout consists of one reservoir, four tanks, five pumps, twenty-five pipes, and one pressure
relief valve. The system elevation and pipe lengths vary throughout the network. The fundamental job
at hand is to alter the diameter of the pipes to maintain specified velocities and pressures for the
system, throughout the varying conditions that will be present in each of the tasks. Analysis of the
system was carried out through utilization of the EPANET2 software provided by www.epa.gov. This
software allows for the placement of tanks, nodes, pipes, valves, pumps, and reservoirs, while also being
able to calculate the velocities of the water in the pipes and the pressures at the nodes. Another benefit
to the software is that it allows the diameters of the pipes to be altered to change the velocities and
pressures. All systems designed in EPANET2 can also be run over a specified period of time, a capability
that is used heavily in this project.
Figure 1 - Plan View
General Set Up of the System
The EPANET2 software is very user friendly and allows for networks to be created by using icons,
which represent links, tanks, reservoirs, valves, and pumps. The building process begins by inserting any
component into the EPANET2 workspace. Once a component has been placed into the workspace, all of
the characteristics associated with that component can be input into the system. Examples of such
characteristics include items such as roughness coefficients, diameters, and lengths for pipes. It should
be noted, however, that each different component will have its own series of important characteristics
and all critical characteristics must be specified. Additional items such as pump curves, water demand
modulation charts, and on/off characteristics must be input in order for the system to operate
successfully. After the system has been created and is running successfully, the next step is to start
minimizing the pipe diameters until the smallest diameter meeting the velocity and pressure
requirements is found. The use of smaller diameters where possible ensures that costs are minimized.
The specifications governing the setup of the network can be found in Appendix A.
Task A
Task A required that a simulation be carried out for the “Average Daily Water Demand”
scenario. This task had two different parts. The first portion of this task required that all water
elevations in the tanks to be set to the levels found in Table 4, while the second portion required that
the water elevations in all tanks be set to full. From a demand perspective, the primary nodes of
interest for this task are nodes 16, 20, 21, 30, and 42. This task requires that the pressure at all nodes
(except 2, 3, & 4) be above 30 psi and that the velocity in all pipes be below 3 ft/s. In order to meet
these requirements, the diameters of the different pipes must be altered. To begin working Task A, all
pipes were set with a diameter of 12 inches. Baseline readings were done with all pipes set at 12 inches
in diameter, as all velocities and pressures were within range. At this point, pipe diameters were made
smaller where possible to keep costs lower. It should be noted that pipe diameters were seen from a
very limited scope at this point in the project and modifications were necessary as later tasks were taken
on, ultimately leading to a system that ran successfully in all situations. These details will be seen as
later tasks are discussed.
Overall, Task A was relatively simple and no big issues were encountered while attempting to achieve
the given requirements. This task was run for a single time period. The velocities and pressures can be
observed in Figures 2 – 5.
Figure 2 & 3 – Velocities Through The Pipes and Pressures at Nodes (Task A Part I)
Figure 4 & 5 – Velocities Through The Pipes and Pressures at Nodes (Task A Part II)
Task B
Task B required a simulation to be carried out for the “Peak Hour Demand” scenario to ensure
the network is able to maintain a minimum pressure of 20 psi at all nodes (except for nodes 2, 3, & 4)
and a maximum velocity of 3 ft/sec in all pipes. This task, like Task A, also had two different parts. The
first portion of this task required that all water elevations in the tanks again be set to the levels given in
Table 4 of the handout. The second portion of this task required that all water elevations in the tanks to
be set as full. This simulation requires that the water demand from the nodes 16, 20, 21, 30, and 42 be
1.5 times the “Average Day Water Demand.” While optimizing the network to meet the requirements
called out for this task, the pipe diameters were adjusted in accordance with the pipes available in Table
3 of the handout. In beginning Task B, the original network used the pipe diameters from Task A. While
using the same network from Task A for Task B seemed as though it should work given the order of tasks
in this project, issues were encountered requiring the pipe diameters to be altered. It was at this point
that our group realized the complexity associated with this project as it became obvious that network
modification was going to be necessary for each task, and the final network was going to have to work
for all tasks. This realization led to a network optimization process used for each task, in which
diameters were adjusted to allow the system to function initially and then later adjusted in smaller
increments to optimize the network. As the requirements specified that pressure must be 20 psi
minimum and velocities must be 3 ft/s maximum, the group discovered that these performance
parameters could be reached, while cost could be minimized by using larger diameter pipes for shorter
distances and smaller diameter pipes for longer distances. This concept was carried throughout the
remainder of the project.
No serious issues were encountered during this task; all requirements were met. The velocities
and pressures are displayed in Figures 06 – 09.
Figure 6 & 7. – Velocities Through The Pipes and Pressures at Nodes (Task B Part I)
Figure 8 & 9. – Velocities Through The Pipes and Pressures at Nodes (Task B Part II)
Task C
Task C required a 5-day extended period simulation be run on the water supply system. This
task also required that the water demand modulation pattern present in Figure 3 of the handout be
used during this simulation. Two patterns were seen in Figure 3. One of the patterns was used for every
node other than node 30 and the other was used specifically for node 30. The demand at node 30 was
much more uniform due to the presence of a 24-hour industry that drew their water supply from this
node. Unlike Tasks A and B, Task C required that the tanks in the system be emptied in order for the
simulation to run. The pressure and velocity requirements for this task were the same as in the previous
task, requiring that pressures be above 20 psi and the velocities be below 3 ft/sec. This task proved to
be more complicated than the previous two tasks, as difficulties were encountered reaching the
pressure and velocity requirements. Tank water levels, pump characteristics, and pipe diameters were
all modified at this point to allow the system to operate as intended. Interestingly, the pumps did not
require operation while running under these circumstances. The changes made to the system did, in
fact, allow for a periodic equilibrium state to be reached. Upon the results obtained, equilibrium was
reached in about 20 hours of operation. The data obtained from completing Task C is can be seen in
Figures 10 – 18 below.
Figure 10. – Time Pattern For Node 30
Figure 11. – Time Pattern for All Nodes (except 30)
Figure 12. – Velocities for Pipes 131, 134, 144, 223, 229
Figure 13. – Velocities for Pipes 101, 102, 103, 122, 123
Figure 14. – Velocities for Pipes 119, 139, 140, 141, 143
Figure 15. – Velocities for Pipes 221, 222, 224, 225, 226
Figure 16. – Velocities for Pipes 115, 117, 118, 120, 124
Figure 17. – Time Variations for Every Tank
Figure 18. – Water Pressure for Nodes with Base Demands
Task D
Task D required that a simulation be carried out for a "Pipe Maintenance" scenario. Within this
scenario, pipe 225 leaked and needed to be taken out of the system for 72 hours to be fixed. Task D also
required an extended 5-day water simulation. Task D did not specify any initial elevations of water in
the tanks. With our setup, neither the water level in tank 23 nor the pressure at node 20 changed.
Because this task did not specify when the pipe needed to be removed from the system, the simulation
was started with it out of the network, and it was reintroduced at hour seventy-two. Figures 19 through
23 show velocity vs. time for the entire run time of 120 hrs for each of the 25 pipes. Analyzing the
velocity graphs, equilibrium appears to be reached 30 hours after the start of the run. Figures 24 and 25
show the pressure at node 20 and the head at tank 23 respectively. All Pipe diameters can be seen in
Figure 26.
Figure 19. – Velocities for Pipes 131, 134, 144, 223, 229
Figure 20. – Velocities for Pipes 101, 102, 103, 122, 123
Figure 21. – Velocities for Pipes 119, 139, 140, 141, 143
Figure 22. – Velocities for Pipes 221, 222, 224, 225, 226
Figure 23. – Velocities for Pipes 115, 117, 118, 120, 124
Figure 24. – Pressure Variations at Node 20
Figure 25. – Tank #23 Water Levels
Figure 26. – Final Diameters for Every Task
Task E
The overall cost of the system is $810,480.00. All costs have been broken down in Tables 1 - 3
below. Costs associated with the tanks and pumps could not be minimized as they were set expenses.
The only costs that could be changed were the pipes. Using pipes of larger diameters drove costs up,
while reducing pipe diameters reduced costs. Using the approach that was mentioned earlier, all pipes
were reduced to the smallest diameter possible, where possible, to minimize costs while allowing all
performance requirements to be met consistently. The cost of pumps, tanks and labor, which again
were fixed, was $63,045.00. The cost of all pipes and labor with diameters and lengths considered was
$747,435.00.
Table 01 – Size and price of cast iron pipes
Diameter (inch)
Cost ($US/ft)
Diameter (inch)
Cost ($US/ft)
4
1.5
18
7.0
6
2.0
20
9.0
8
2.5
24
12.0
10
3.0
30
15.5
12
3.5
36
21.0
14
4.5
12
27.0
16
5.5
18
35.0
Table 02. – Overall Pump and Tank Cost
TANKS Capital Costs
Labor Costs
Quantity
17
$ 5,600.00
$ 1,960.00
1
23
$ 3,400.00
$ 1,190.00
1
31
$ 3,400.00
$ 1,190.00
1
43
$ 4,500.00
$ 1,575.00
1
1
$ 8,800.00
$ 3,080.00
1
PUMPS
1
$ 4,800.00
$ 1,680.00
1
2
$ 4,800.00
$ 1,680.00
1
3
$ 4,800.00
$ 1,680.00
1
39
$ 3,300.00
$ 1,155.00
1
40
$ 3,300.00
$ 1,155.00
1
Total
$ 46,700.00
$ 16,345.00
10
Total
$63,045.00
PIPE
101
102
103
115
117
118
119
120
122
123
124
131
134
139
140
141
143
144
221
222
223
224
225
226
229
TOTAL
Table 03. –Overall Pipe Cost
DIAMETER
LENGTH
CAPITAL COST
30
10
$
155.00
30
10
$
155.00
30
10
$
155.00
48
2000
$ 70,000.00
36
200
$ 4,200.00
24
2000
$ 24,000.00
24
10
$
120.00
20
10
$
90.00
30
10
$
155.00
30
10
$
155.00
30
10
$
155.00
30
200
$ 3,100.00
4
20000
$ 30,000.00
24
10
$
120.00
20
10
$
90.00
30
15000
$ 232,500.00
30
200
$ 3,100.00
4
2000
$ 3,000.00
16
7000
$ 38,500.00
16
7000
$ 38,500.00
30
200
$ 3,100.00
16
200
$ 1,100.00
16
5000
$ 27,500.00
24
5000
$ 45,000.00
12
10000
$ 35,000.00
LABOR COST
$
46.50
$
46.50
$
46.50
$ 21,000.00
$ 1,260.00
$ 7,200.00
$
36.00
$
27.00
$
46.50
$
46.50
$
46.50
$
930.00
$ 9,000.00
$
36.00
$
27.00
$ 69,750.00
$
930.00
$
900.00
$ 11,550.00
$ 11,550.00
$
930.00
$
330.00
$ 8,250.00
$ 13,500.00
$ 10,500.00
$ 747,435.00
Overall Discussion
This project required the use of innovative thinking along with problem solving and design skills.
As we began this project, trial and error was used to figure out how the system would operate as work
was done to better understand the nature of the project, as well as the software; as more tasks were
completed, however, our group began to develop a design procedure that allowed us to meet the
performance requirements while minimizing costs. In retrospect, there would have been some benefit
in looking ahead at all tasks in consideration of the initial network design. Doing this would have
allowed the tasks to be completed more easily and efficiently. Having completed this project, the group
has learned to better consider problems from a macroscopic view, before breaking them down into
subtasks. Some trial and error is still beneficial when taking on simulations such as these, as the nature
of networks such as this make it very difficulty to immediately realize the outcome of certain
modifications. Overall, each group member gained better problem solving skills and design skills in their
application to hydraulic analysis.
Appendix A
Reservoir
 Elevation of 120 feet
Five pumps with two different pump curves
 Pumps 1, 2, & 3 with 200 ft at discharge = 5000 gpm
 Pumps 39 & 40 with 150 ft at discharge = 2000 gpm
Four tanks
 Tank 17 with a diameter of 200 ft and an elevation of 265 ft with an initial level set at 30 feet
 Tank 23 with a diameter of 60 ft and an elevation of 260 ft with an initial level set at 20 feet
 Tank 31 with a diameter of 60 ft and an elevation of 260 ft with an initial level set at 20 feet
 Tank 43 with a diameter of 85 ft and an elevation of 350 ft with an initial level set at 30 feet
 Tanks have a maximum water level of 40 feet and a minimum level of 0 feet
Pressuring reducing valve
 Diameter = 16 inches
 Operates when pressure is below 60 psi
 Has a loss efficiency of 80%
Pump controls:
Pump #1 was controlled by node 17
 On when water level is between 20 and 38 feet
Pump #2 was controlled by node 17
 On when water level is between 10 and 30 feet
Pump #2 was controlled by node 17
 On when water level is between 5 and 20 feet
Pump #39 was controlled by node 43
 On when water level is between 25 and 38 feet
Pump #40 was controlled by node 43
Pipe#
115
117
118
221
222
223
224
225
226
229
Node#
1
2, 3, 4
12, 13, 14, 15
16
17
18, 19, 38
20
21, 22
Diameter (inch)
4
6
8
10
12
14
16
Table 1 Pipe Lengths used in the System
Length (ft) Pipe#
200
2,000
7,000
7,000
200
200
5,000
5,000
10,000
2,000
131
134
141
143
144
101, 102, 103
122, 123, 124
119, 120
139, 140
Table 2 Elevations at Individual Nodes
Elevation (ft)
Node#
120
23
100
30
100
31
100
34
265
39, 40, 41
100
42
125
43
100
44
Table 3 Size and price of cast iron pipes
Cost ($US/ft)
Diameter (inch)
1.5
18
2.0
20
2.5
24
3.0
30
3.5
36
4.5
42
5.5
48
Length
(ft)
200
20,000
15,000
200
2,000
10
10
10
10
Elevation (ft)
260
125
260
125
100
250
350
125
Cost ($US/ft)
7.0
9.0
12.0
15.5
21.0
27.0
35.0
Node #
17
23
31
43
1
Pump #
ON
1
2
3
39
40
Table 4 Details of Water Tanks
Max. water Min. water
Initial water Diameter of
level (ft)
level (ft)
level (ft)
tank (ft)
40.0
0.0
30.0
200
40.0
0.0
20.0
60
40.0
0.0
20.0
60
40.0
0.0
30.0
85
Maintained
1,000
8,800
Elevation at 120 ft
17
17
17
43
43
Table 5 Pump Operation and Cost
Controlled by Node #
Cost ($US/unit)
OFF
4,800
20.0
4,800
10.0
4,800
5.0
3,300
25.0
3,300
10.0
Cost
($US/unit)
5,600
3,400
3,400
4,500
Water Level (ft)
38.0
30.0
20.0
38.0
30.0
Pipes and Nodes
25 total pipes
 Cast iron
 Darcy –Weisbach coefficient of .85
 Diameters ranging from 4 – 48 inches
 Lengths ranging from 10 – 20000 feet
Nodes
 #16 with a demand 2400 gpm at 100 feet
 #20 with a demand 1500 gpm at 125 feet
 #21 with a demand 300 gpm at 100 feet
 #30 with a demand of 600 gpm at 125 feet
 #42 with a demand of 1200 gpm at 250 feet
 17 other nodes used as junctions with various elevations
Pressure Reducing Valve (PRV)
The PRV between nodes #34 and #44 has a diameter of 16”. When the pressure is below 60 psi and has
the loss efficiency of 80%, the PRV will become set to operate.
Average daily water demand (ADWD)
The average water demand information at the water use nodes is provided in the plan view of the water
distribution system in Figure 1.
Peak hour water demand (PHWD)
Peak hour water demand can be calculated based on ADWD using the following simple relationship:
PHWD = 1.5ADWD
Modulation of water demand during a typical day
The water users served at all of the nodes except 30 are domestic and commercial users whose water
consumption rates vary. The water users at node #30 consist primarily of an industry that operates 24
hours a day and has a much more uniform consumption pattern. The water demands for all nodes are
shown in Figure 3. The ordinate is a multiplier of the ADWD for all nodes. These time patterns are also
used for extended period analyses.