Colorado Replenishment Pipeline
Design Proposal
ME 555 – Thermal Systems Design
College of Engineering
San Diego State University
Prepared for
Dr. Asfaw Beyene
Prepared by
Jonathan Butbul, Eric Miller, Nam Ngo
November 1, 2010
1 | Colorado Replenishment Pipeline
Contents
1.
SCOPE............................................................................................................................. 2
2.
OBJECTIVE ...................................................................................................................... 2
3.
MAJOR ASSUMPTIONS ................................................................................................... 2
4.
BACKGROUND DATA....................................................................................................... 4
5.
DESIGN CONCEPT............................................................................................................ 5
5.1.
5.2.
5.3.
5.4.
PIPELINE ROUTE................................................................................................................................................5
PIPING SYSTEM .................................................................................................................................................8
PUMPING SYSTEM .............................................................................................................................................5
WATER TREATMENT SYSTEM ...............................................................................................................................9
6.
COST ESTIMATES .......................................................................................................... 10
7.
OTHER CONCERNS ........................................................................................................ 11
8.
REFERENCES ................................................................................................................. 13
Abstract
A system is proposed that will pump water from the Pacific Ocean into the Colorado River as it
crosses the US border into Mexico. This system uses over 216 pumps and 172 miles of piping to
increase the flow rate at the pipeline’s exit by 15,189 cubic feet per second. Finally, the cost of
the system is estimated to evaluate the economic feasibility.
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2 | Colorado Replenishment Pipeline
1.
Scope
The Colorado River spans five states, running approximately 1,450 miles from Colorado to
northwest Mexico. It is an essential source of water for the majority of Southwest America, as
well as a large provider of clean and renewable energy. In recent decades, the river discharge
has been modified various dams and diversion for irrigation. Construction of these dams has
dramatically altered the surrounding geography; several lakes and reservoirs have been created
along the river’s path. Due to an international agreement with Mexico, the United States is
required to maintain the Colorado River at a minimum flow rate of 2,139 cubic feet per second
upon crossing into Mexico [3].
1.
Objective
The objective of this project is to design a system that will pump water from the Pacific Ocean
to the Colorado River, in order to restore the flow rate near the U.S-Mexico border to it average
flow rate upstream near the Hoover dam. The water must be desalinized and treated, so that
its cleanliness is roughly equal to that of the Colorado River.
2.
Major Assumptions
In order to simplify the analysis and design of this system, several major assumptions will be
made.
Assumption 1. Pipeline Route
The pipeline route will follow the shortest path along a major highway from the Pacific Ocean
near San Diego to the Colorado River near Yuma, Arizona. The elevation profile will consist of an
initial horizontal section, a climb to the maximum elevation, another horizontal section, a
descent to the final elevation, and a final horizontal section.
Assumption 2. Installation and Maintenance
The proposed design will not describe installation and maintenance procedures. The only
exception will be the decision to route the pipeline along a major highway for ease of access in
case of necessary maintenance.
Assumption 3. Pipes and Joints
The proposed design will not address issues related to thermal expansion of the pipes or joints.
Minor head losses (e.g., those due to pipe joints, connections) will be neglected. Major head
loss calculations will only consider pipeline segments S2 and S3, and will assume that their
combined length is the entire distance of the pipeline route, multiplied by the number of
pipelines in parallel.
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3 | Colorado Replenishment Pipeline
Assumption 4. Pump Operating Conditions
Because limited data is available on the type of pumps required for this project, pump
operating conditions will be assumed for each pumping station. Details about assumed
operating conditions can be found in Section 5.2.
Assumption 5. Water Treatment Facilities
The proposed water treatment design will assume similar operating conditions and facilities to
that of an existing desalinization plant in current operation. Startup and variable costs will be
scaled up proportionally to the flow rates of the existing and proposed plants. The water
treatment process will only describe the removal of salt, and the cost and operating conditions
of the plant will be assumed to clean the water to the same quality as the model existing plant.
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4 | Colorado Replenishment Pipeline
3.
Background Data
3.1.
Geological Data
The dam directly preceding the Hoover dam on the Colorado River is the Glen Canyon Dam. The
volume flow rate is measured near the exit of this dam at a station called Lee’s Ferry. The
average flow rate at this station from 1945 to 2009 was 17,850 cubic feet per second [2].
As the Colorado River crosses the US-Mexico border, the volume flow rate is estimated to be
2,661 cubic feet per second [3].
3.2.
Geographic Data
The shortest highway route from the Pacific Ocean to the Colorado River at the US-Mexico
Border is 172 miles along Interstate Highway 8. The maximum elevation along this route is
4,199 feet above mean-sea-level, which occurs 72 miles along the route. A map of the pipeline
route is shown below in Figure 1.
Figure 1. The selected route (bright pink) follows I-8 from San Diego to Yuma. The elevation
profile for the selected route is plotted below. The path of the Colorado River is highlighted in
light blue. The US-Mexico International Border is shown in yellow.
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Design Concept
3.3.
Overall Concept
A top-level system schematic is shown in Figure2. The proposed design begins with offshore
pumping station P1, which pumps seawater from the Pacific Ocean to the desalinization plant.
At the desalinization plant, the majority of the salt is removed, and the fresh water is collected
into reservoir R1. Next, the secondary pumping station P2 provides most of the dynamic head
necessary to cross the Sierra Nevada mountain range on the way toward the Colorado River. A
third pumping station P3 provides the rest of the dynamic head necessary for the last segment,
which empties into the Colorado River approximately 5 miles north of the US-Mexico
International Border.
For more details about the piping stations, the pipeline segments, and the desalinization plant,
please see Sections 5.3., 5.4., and 5.5., respectively.
Figure 2. System Schematic
3.4.
Pumping System
The pumping required for this system is split into three large stations.
The first station, P1 pumps saltwater from the Pacific Ocean inland to the desalinization plant.
The inlet to the desalinization plant will be no more than 30 feet above sea-level (𝑯𝑷𝟏 =
𝟑𝟎 𝒇𝒕). The desalinization plant processes water at an 80 percent throughput efficiency (see
Section 5.5), meaning pumping station P1 must pump more water than any other station in
order to meet the required flow rate for the rest of the system (Equation 1).
𝑸𝑷𝟏 =
𝑄𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑
15,189 𝑐𝑓𝑠
=
= 𝟏𝟖, 𝟗𝟖𝟔 𝒄𝒇𝒔
% 𝑇ℎ𝑟𝑜𝑢𝑔ℎ𝑝𝑢𝑡
0.80
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(1)
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A set of wet pit column pumps (Goulds Pumps, Seneca Falls, NY) will be connected in parallel to
meet the required flow rate for station P1. Because limited performance data is available for
this pump, operating conditions will be assumed at 90 percent of the maximum published
capacity and 5 percent of the maximum published head [Ref: Goulds Pump Catalog]. Therefore,
each wet pit column pump will impart 1,003 cfs of seawater with 30 feet of dynamic head, for a
total power output of 267 kW (Equations 2-4).The energetic efficiency of each pump at these
operating conditions will be assumed at 80 percent, thus the input power required will be 334
kW (Equation 5). A total of 19 pumps will be required to meet the required flow rate for this
station (Equation 6), so the total input power required for station P1 pumps is 6.35 MW
(Equation 7).
𝑸𝑾𝑷𝑪,𝑶𝒑𝒔,𝑷𝟏 = 𝑄𝑊𝑃𝐶,𝑀𝑎𝑥 ∗ (% 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦) = 500,000 𝐺𝑃𝑀 ∗ 0.90 = 𝟒𝟓𝟎, 𝟎𝟎𝟎 𝑮𝑷𝑴 [𝟏, 𝟎𝟎𝟑 𝒄𝒇𝒔; 𝟐𝟖. 𝟑𝟗 𝒎𝟑 ∙ 𝒔−𝟏 ]
(2)
𝑯𝑾𝑷𝑪,𝑶𝒑𝒔,𝑷𝟏 = 𝐻𝑊𝑃𝐶,𝑀𝑎𝑥 ∗ (% 𝐻𝑒𝑎𝑑) = 600 𝑓𝑡 ∗ 0.05 = 𝟑𝟎 𝒇𝒕 [𝟗. 𝟏𝟒𝟒 𝒎]
(3)
𝑷𝑾𝑷𝑪,𝑶𝒖𝒕𝒑𝒖𝒕,𝑷𝟏 = 𝑄𝑊𝑃𝐶,
𝑂𝑝𝑠
∗ 𝐻𝑊𝑃𝐶,𝑂𝑝𝑠,𝑃1 ∗ 𝜌𝑆𝑒𝑎𝑤𝑎𝑡𝑒𝑟 = 28.39 𝑚3 𝑠 −1 ∗ 9.144 𝑚 ∗ 1030𝑘𝑔 ∙ 𝑚−3 = 𝟐𝟔𝟕, 𝟑𝟖𝟔 𝑾
𝑷𝑾𝑷𝑪,𝑰𝒏𝒑𝒖𝒕,𝑷𝟏 = 𝑃𝑊𝑃𝐶,𝑂𝑢𝑡𝑝𝑢𝑡,𝑃1 ÷ 𝜂𝑊𝑃𝐶,𝑃1 = 267386 𝑊 ÷ 0.80 = 𝟑𝟑𝟒, 𝟐𝟑𝟐 𝑾 [𝟑𝟑𝟒 𝒌𝑾]
𝒏𝑾𝑷𝑪,𝑷𝒂𝒓𝒂𝒍𝒍𝒆𝒍,𝑷𝟏 = 𝑄𝑃1 ÷ 𝑄𝑊𝑃𝐶,𝑂𝑝𝑠,𝑃1 = 18,986 𝑐𝑓𝑠 ÷ 1,003 𝑐𝑓𝑠 ≈ 𝟏𝟗 𝒑𝒖𝒎𝒑𝒔
𝑷𝑰𝒏𝒑𝒖𝒕,𝑷𝟏 = 𝑃𝑊𝑃𝐶,𝐼𝑛𝑝𝑢𝑡,𝑃1 ∗ 𝑛𝑊𝑃𝐶,𝑃𝑎𝑟𝑎𝑙𝑙𝑒𝑙,𝑃1 = 334,232 𝑊 ∗ 19 = 𝟔, 𝟑𝟓𝟎, 𝟒𝟎𝟖 𝑾 [𝟔. 𝟑𝟓 𝑴𝑾]
(4)
(5)
(6)
(7)
The second station, P2 will pump fresh water from reservoir R1 up and over most of the Sierra
Nevada mountain range. This station will impart into the water most of the dynamic head
required to reach the Colorado River. The flow rate required of this pumping station is the same
as the total flow rate required of the entire system (𝑸𝑷𝟐 = 𝟏𝟓, 𝟏𝟖𝟗 𝒄𝒇𝒔).
Pumping station P2 will use high-head vertical industrial turbine pumps (Goulds Pumps)
operating in parallel. Because limited information is available about these pumps, operating
conditions will be assumed at 75 percent of the maximum published capacity and 75 percent of
the maximum published head. Therefore, each pump will impart 109 cfs of water with 2625
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7 | Colorado Replenishment Pipeline
feet of head, for an output power of 2.46 MW per pump (Equations 8-10). The energetic
efficiency at these operating conditions is assumed to be 85 percent, thus each pump requires
2.895 MW power at its input (Equation 11). In order to meet flow rate requirements for this
station, 140 pumps must be connected in parallel (Equation 12), for a total input power of
405.3 MW at pumping station P2 (Equation 13).
𝑸𝑽𝑰𝑻,𝑶𝒑𝒔 = 𝑄𝑉𝐼𝑇,𝑀𝑎𝑥 ∗ (% 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦) = 65,000 𝐺𝑃𝑀 ∗ 0.75 = 𝟒𝟖, 𝟕𝟓𝟎 𝑮𝑷𝑴 [𝟏𝟎𝟖. 𝟔 𝒄𝒇𝒔; 𝟑. 𝟎𝟕𝟔 𝒎𝟑 ∙ 𝒔−𝟏 ]
(8)
𝑯𝑽𝑰𝑻,𝑶𝒑𝒔 = 𝐻𝑉𝐼𝑇,𝑀𝑎𝑥 ∗ (% 𝐻𝑒𝑎𝑑) = 3500 𝑓𝑡 ∗ 0.75 = 𝟐𝟔𝟐𝟓 𝒇𝒕 [𝟖𝟎𝟎 𝒎]
(9)
𝑷𝑽𝑰𝑻,𝑶𝒖𝒕𝒑𝒖𝒕 = 𝑄𝑉𝐼𝑇,𝑂𝑝𝑠 ∗ 𝐻𝑉𝐼𝑇,𝑂𝑝𝑠 ∗ 𝜌𝑤𝑎𝑡𝑒𝑟 = 3.076 𝑚3 𝑠 −1 ∗ 800 𝑚 ∗ 1000𝑘𝑔 ∙ 𝑚−3 = 𝟐, 𝟒𝟔𝟎, 𝟖𝟎𝟎 𝑾
(10)
𝑷𝑽𝑰𝑻,𝑰𝒏𝒑𝒖𝒕 = 𝑃𝑊𝑃𝐶,𝑂𝑢𝑡𝑝𝑢𝑡 ÷ 𝜂𝑊𝑃𝐶 = 2460800 𝑊 ÷ 0.85 = 𝟐, 𝟖𝟗𝟓, 𝟎𝟓𝟖 𝑾 [𝟐. 𝟖𝟗𝟓 𝑴𝑾]
(11)
𝒏𝑽𝑰𝑻,𝑷𝒂𝒓𝒂𝒍𝒍𝒆𝒍,𝑷𝟐 = 𝑄𝑃2 ÷ 𝑄𝑉𝐼𝑇,
𝑂𝑝𝑠
(12)
= 15,189 𝑐𝑓𝑠 ÷ 108.6 𝑐𝑓𝑠 ≈ 𝟏𝟒𝟎 𝒑𝒖𝒎𝒑𝒔
(13)
𝑷𝑰𝒏𝒑𝒖𝒕,𝑷𝟐 = 𝑃𝑉𝐼𝑇,𝐼𝑛𝑝𝑢𝑡 ∗ 𝑛𝑉𝐼𝑇,𝑃𝑎𝑟𝑎𝑙𝑙𝑒𝑙,𝑃2 = 2.895 𝑀𝑊 ∗ 140 = 𝟒𝟎𝟓, 𝟑𝟎𝟖, 𝟏𝟐𝟎 𝑾 [𝟒𝟎𝟓. 𝟑 𝑴𝑾]
The third and final station, P3 will be located 2550 feet up the Sierra Nevada mountain range,
and will pump the water the rest of the way to the Colorado River. The entire system flow rate
will pass through Station P3 (𝑸𝑷𝟑 = 𝟏𝟓, 𝟏𝟖𝟗 𝒄𝒇𝒔). The max elevation of the pipeline is 4,200
feet, and the initial estimate of major and minor pipe losses is 1000 ft. So, Station P3 must
impart 2575 feet of head into the water for it to reach the Colorado River (Equation 14).
𝑯𝑷𝟐 = 𝐻𝑇𝑜𝑡𝑎𝑙 = 𝐻𝐸𝑙𝑒𝑣𝑎𝑡𝑖𝑜𝑛 + 𝐻𝑀𝑎𝑗𝑜𝑟 + 𝐻𝑀𝑖𝑛𝑜𝑟 − 𝐻𝑃1 = 4200 𝑓𝑡 + 1000 𝑓𝑡 − 2625 𝑓𝑡 = 𝟐𝟓𝟕𝟓 𝒇𝒕
(14)
Pumping station P3 will use the same wet pit column pumps from Station P1 (Goulds Pumps).
Because limited information is available about these pumps, operating conditions will be
assumed at 75 percent of the maximum published capacity and 75 percent of the maximum
published head. Therefore, each pump will impart 835.5 cfs of water with 675 feet of head, for
an output power of 4.9 MW per pump (Equations 15-17). The energetic efficiency at these
operating conditions is assumed to be 85 percent, thus each pump will require 5.727 MW of
power at its input (Equation 18). In order to meet flow rate requirements for this station, 19
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8 | Colorado Replenishment Pipeline
pumps must be connected in parallel (Equation 19), and in order to meet head requirements
for this station, 4 pumps must be connected in series (Equation 20), for a total input power of
435.2 MW at pumping station P3 (Equation 21).
𝑸𝑾𝑷𝑪,𝑶𝒑𝒔,𝑷𝟐 = 𝑄𝑊𝑃𝐶,𝑀𝑎𝑥 ∗ (% 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦) = 500,000 𝐺𝑃𝑀 ∗ 0.75 = 𝟑𝟕𝟓, 𝟎𝟎𝟎 𝑮𝑷𝑴 [𝟖𝟑𝟓. 𝟓 𝒄𝒇𝒔; 𝟐𝟑. 𝟔𝟓𝟗 𝒎𝟑 ∙ 𝒔−𝟏 ]
(15)
𝑯𝑾𝑷𝑪,𝑶𝒑𝒔,𝑷𝟐 = 𝐻𝑉𝐼𝑇,𝑀𝑎𝑥 ∗ (% 𝐻𝑒𝑎𝑑) = 900 𝑓𝑡 ∗ 0.75 = 𝟔𝟕𝟓 𝒇𝒕 [𝟐𝟎𝟓. 𝟕𝟒 𝒎]
(16)
𝑷𝑾𝑷𝑪,𝑶𝒖𝒕𝒑𝒖𝒕,𝑷𝟐 = 𝑄𝑉𝐼𝑇,𝑂𝑝𝑠,𝑃2 ∗ 𝐻𝑉𝐼𝑇,𝑂𝑝𝑠,𝑃2 ∗ 𝜌𝑤𝑎𝑡𝑒𝑟 = 23.659 𝑚3 𝑠 −1 ∗ 205.74 𝑚 ∗ 1000𝑘𝑔 ∙ 𝑚−3 = 𝟒, 𝟖𝟔𝟕, 𝟔𝟎𝟑 𝑾 [𝟒. 𝟖𝟔𝟖 𝑴𝑾]
(17)
𝑷𝑾𝑷𝑪,𝑰𝒏𝒑𝒖𝒕,𝑷𝟐 = 𝑃𝑊𝑃𝐶,𝑂𝑢𝑡𝑝𝑢𝑡,𝑃2 ÷ 𝜂𝑊𝑃𝐶,𝑃2 = 4867603 𝑊 ÷ 0.85 = 𝟓, 𝟕𝟐𝟔, 𝟓𝟗𝟏 𝑾 [𝟓. 𝟕𝟐𝟕 𝑴𝑾]
(18)
𝒏𝑾𝑷𝑪,𝑷𝒂𝒓𝒂𝒍𝒍𝒆𝒍,𝑷𝟐 = 𝑄𝑃2 ÷ 𝑄𝑊𝐼𝐶,𝑂𝑝𝑠,𝑃2 = 15,189 𝑐𝑓𝑠 ÷ 835.5 𝑐𝑓𝑠 ≈ 𝟏𝟗 𝒑𝒖𝒎𝒑𝒔
3.5.
(19)
𝒏𝑾𝑷𝑪,𝑺𝒆𝒓𝒊𝒆𝒔,𝑷𝟐 = 𝐻𝑃2 ÷ 𝐻𝑊𝐼𝐶,𝑂𝑝𝑠,𝑃2 = 2,725 𝑓𝑡 ÷ 675 𝑐𝑓𝑠 ≈ 𝟒 𝒑𝒖𝒎𝒑𝒔
(20)
𝑷𝑰𝒏𝒑𝒖𝒕,𝑷𝟐 = 𝑃𝑊𝑃𝐶,𝐼𝑛𝑝𝑢𝑡,𝑃2 ∗ 𝑛𝑉𝐼𝑇,𝑃𝑎𝑟𝑎𝑙𝑙𝑒𝑙,𝑃2 ∗ 𝑛𝑊𝑃𝐶,𝑆𝑒𝑟𝑖𝑒𝑠,𝑃2 = 5.727 𝑀𝑊 ∗ 19 ∗ 4 = 𝟒𝟑𝟓, 𝟐𝟐𝟎, 𝟗𝟏𝟔 𝑾 [𝟒𝟑𝟓. 𝟐 𝑴𝑾]
(21)
Piping System
The proposed piping design for segments S2 and S3 will use commercial steel pipes that are 184
inches in diameter (Pipe Industries Corp., Commerce City, CO). Because these pipes are so
large, the relative roughness is very small (less than 0.0001), thus the Haaland Equation for
friction factor is appropriate. The friction factor is therefore equal to 0.00894.
𝒇=
. 𝟑𝟎𝟖𝟔𝒏𝟐
𝟕. 𝟕 𝒏
𝜺 𝟏.𝟏𝟏𝒏
{𝒍𝒐𝒈 [(
) +(
)
]}
𝑹𝒆𝑫
𝟑. 𝟕𝑫
𝟐
= . 𝟎𝟎𝟖𝟗𝟒𝟐𝟓𝟒
Pipe Information
Total Number of Pipes
19
Flow through each Pipe
799.42 CFS
Pipe Cross-Sectional Area
184.655 ft2
Velocity through Single Pipe 4.329245
Reynolds Number
6008732.3= 6.00*106
ε/D
.ooo15in/184in=
8.152*10-7
Using the Darcy-Weisbach formula, the major losses are calculated to be 67 feet in each
pipeline in segment S2 and 241 feet for each pipeline in segment S3.
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9 | Colorado Replenishment Pipeline
𝒉𝒇,𝑺𝟐 = 𝒇𝒅−𝒘
𝒉𝒇,𝑺𝟑
3.6.
𝑳 𝑽𝟐
𝟏𝟗𝟖𝟎𝟎𝟎𝒇𝒕 𝟒. 𝟑𝟑𝒇𝒕/𝒔𝟐
=. 𝟎𝟎𝟖𝟗𝟒𝟐 ∗
= 𝟔𝟕. 𝟐𝟑𝟒𝟓 𝐟𝐭
𝑫 𝟐𝒈
𝟏𝟓. 𝟑𝟑𝟑𝒇𝒕 𝟑𝟐. 𝟐
𝟑𝟑𝒇𝒕𝟐
𝟕𝟏𝟎𝟏𝟔𝟎𝒇𝒕 𝟒. 𝒔
=. 𝟎𝟎𝟖𝟗𝟒𝟐 ∗
= 𝟐𝟒𝟏. 𝟏𝟗𝟓 𝒇𝒆𝒆𝒕
𝟏𝟓. 𝟑𝟑𝟑𝒇𝒕 𝟑𝟐. 𝟐
Water Treatment System
The reverse osmosis process removes large dissolved molecules from fluid solutions by applying
a high pressure to the fluid when it’s on one side of a selective membrane. The particles are
then left behind in the volume in front of the membrane, while the purified fluid passes
through.
Figure 3: Basic scheme of desalination by RO [6]
The process can also be made more efficient by recovering some of the flow energy from the
brine waste product via a turbine, which can power the pumps that run the filtration process.
Figure 4: Recover Energy using a turbine [6]
Department of Mechanical Engineering | San Diego State University
Copyright 2010
10 | Colorado Replenishment Pipeline
The largest desalinization plant in the US, located in Tampa, Florida has a maximum capacity of
approximately 45.78 cubic feet per second [7]. Assuming an 80 throughput percentage, this
proposed design will require 18,986 cubic feet per second (Equation 1). This is 415 times the
flow capacity of the Tampa plant.
The Tampa plant cost 150 million to start up, and gets .659 cents per cubic meter of drinkable
water[7]. Scaling up these figures due to the increase in flow, the estimated cost per year to
desalinate 18,986 cubic feet per second of water will be $105 million annually
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4.
Estimated cost of startup : 1 billion dollars
.659 cents per cubic meter
18986 cfs to 538 m^3/s
538m^3/s*.659cent/m^3 = $3.36/sec
Annual Cost = 31536000 (s/year)*$3.33/sec = $105,960,960/year
Cost Estimates
Because the prices of many of the selected components were not available, the prices below
are all very rough estimates.
The wet pit column pumps from Goulds Pumps were estimated to cost $150,000. The total cost
of 171 of these pumps will be $25,650,000
$150000/pump* 171pumps = $2565000
The selected piping is estimated to cost $1000/ft. The total cost of four 172-mile or 908,160
feet for 19 pipelines will be $17,255,040,000.
172mi*5280ft/mi*$1000/ft* 19 = $17,255,040,000
The total power required by the three pumping stations is 846 MW. Assuming continuous
operation, the total energy required every year by these stations will be 26.78 GWh. Assuming
a cost of $0.10/KWh, the energy required to run the pumping stations will cost $2,678 billion
every year.
846MW*3600s/hr*8765.81277hr/year = 26.78GWh
26.78GWh*(10^6 KWh/gwh)*($0.10/KWh) = 2678 *10^9/year
Department of Mechanical Engineering | San Diego State University
Copyright 2010
11 | Colorado Replenishment Pipeline
Hoover Dam generates 4.2 billion KWh annually [5], according to our calculation the power
needed to run these pumps is 26.78 GWh, or .2678 billion KWh, 15 times less than the Hoover
dam.
4.2/.2678 = 15.68
5.
Other Concerns
Steady State:
Once the system reaches steady state, the head that must be overcome is no longer the
maximum elevation; rather it is the major losses plus the height difference of the final
destination and the origin. This head is a considerably less. To take advantage of this
phenomenon, turbines can be positioned along the down-slope of the mountain range to
generate power, or multiple pumps can be turned off to save power. The flow would have to be
diverted around these shut-down pumps.
Pump Failure:
There are 18 lines, and hundreds of pumps that make up this intricate system, it is only a minor
problem if one or two pumps fail. The real problem come in when a pump connected in series
breaks down, a water dam would be created because water cannot flow through a broken
pump. To remedy this problem an emergency water diversion scheme must be established.
Noise Pollution:
One pump is already a nuisance, but having over a hundred pumps located in close proximity is
a real big problem.
Environmental Changes:
This project is the equivalent of constructing a river. Because such a massive amount of water is
being pumped to one location, it will create drastic changes in the surrounding environment.
The Hoover dam was built not only to supply energy, but also to prevent floods. In order to
prevent an overflow of water, the flow would have to be increased slowly at first, and
controlled to supply less or more water when needed.
Real Estate Costs:
The desalination plant itself would take up prime real estate in an already crowded city, so
allocating space for it would be a very expensive undertaking.
Department of Mechanical Engineering | San Diego State University
Copyright 2010
12 | Colorado Replenishment Pipeline
6.
Conclusion
Due to the vast distance, high elevation, and enormous flow that must be pumped, the cost for
the energy alone to run this system would be astronomical. It is not a realistic situation to
pump the water all the way to the Colorado. If the government were to seek a system that
would increase the flow rate of the river as it enters Mexico, they should consider this system
as a very last resort.
Department of Mechanical Engineering | San Diego State University
Copyright 2010
13 | Colorado Replenishment Pipeline
7.
References
[1] Hodge, B.K., & Taylor, R.P. (1999). Analysis and design of energy systems. Upper Saddle
River, New Jersey: Prentice Hall.
[2] Water data report: lee’s ferry test station. (n.d.). Retrieved from
http://waterdata.usgs.gov/usa/nwis/uv?site_no=09380000 on
November 1, 2010.
[3 Pacific institute recommendations report. (n.d.). Retrieved from
http://pacinst.org/reports/streamgages/co_r_streamgages_report.pdf on November 1,
2010.
[5] Hoover dam frequently asked questions. (n.d.). Retrieved from
http://www.usbr.gov/lc/hooverdam/faqs/powerfaq.html on November 1, 2010.
[6] Lachish, U. (n.d.). Optimizing the efficiency of reverse osmosis seawater desalination.
Retrieved from http://urila.tripod.com/Seawater.htm on November 1, 2010.
[7] Tampa bay seawater desalinization plant, florida. Retrieved from http://www.water
technology.net/projects/tampa/ on November 1, 2010.
Department of Mechanical Engineering | San Diego State University
Copyright 2010