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PHOTOGRAPHS
HISTORICAL AND DESCRIPTIVE DATA
•
Historic American Engineering Record
National Park Service
Rocky Mountain Regional Office
Department of the Interior
P.O. Box 25287
Denver, CO. 80225
Shoshone Hydroelectric Plant Comple
HAER No. CO-5
(Page 1)
0 L.C
HISTORIC AMERICAN ENGINEERING RECORD
a<''2> " (s'L E
THE SHOSHONE HYDROELECTRIC PLANT COMPLEX
Location:
60111 U.S. Highway 6, Glenwood Canyon,
Garfield County, Colorado
UTM Coordinates:
Hydro Plant: 13/308780 4382210
Intake Dam:
13/311640 4384060
Diversion Tunnel: A. 13/308760
B. 13/308850
C. 13/309110
D. 13/309490
E. 13/310020
F. 13/310680
G. 13/311220
H. 13/311320
I. 13/311600
J. 13/311640
Quad: Shoshone, Colorado
Dates of Construction:
Hydro plant (1908-09); diversion dam (1907-10);
diversion tunnel (1907-09); dates for support
buildings and structures vary from 1907 to 1978.
Present Owner:
Public Service Company of Colorado
550 15th Street
Denver, Colorado 80202
Present Use:
Generation of hydroelectric power.
Significance:
Historian:
4382280
4382650
4382980
4383070
4383010
4383380
4383840
4384000
4384130
4384110
The Shoshone complex is significant for being one
of the earliest hydroelectric plants on the Colorado
River and one of the largest in the Rocky Mountain
Region to depend upon the flow of a river for its
source of power rather than on the stored water
of a reservoir. It is also significant as a
remarkable engineering accomplishment in terms
of the physical difficulties of construction
within Glenwood Canyon and the scale of the undertaking.
Kenneth M. Gambrill
Colorado Department of Highways
January, 1983
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 2)
Introduction
Construction of the Shoshone Hydroelectric Plant complex in Glenwood
Canyon, Colorado, was an engineering accomplishment of great proportions
in the first decade of the twentieth century.
Begun near the end of 1906
and completed by the spring of 1911, the complex consists of the power
plant and its support buildings, a 2 1/3-mile long water diversion tunnel,
an intake diversion dam, and a 153-mile power transmission line.
The
hydro plant, tunnel, and dam were determined eligible to the National
JUBJIT
Register of Historic Places under Criteria "A" and "C" in March, 1980.
The transmission line has been found to be ineligible for inclusion on
the Register.
Projected growth and development along Colorado's western slope and a
federal mandate to complete the network of Interstate highways have led
to the planned construction of Interstate 70 through Glenwood Canyon.
The accepted design calls for replacing the existing two-lane U.S.
Highway 6 with a modern four-lane divided Interstate roadway carefully
adapted to a combination of engineering, environmental and aesthetic
considerations.
The Federal Highway Administration is the lead agency
in-charge of the proposed undertaking, Project I 70-2(70), Glenwood
Canyon.
The Colorado Department of Highways is the state agency directly
responsible for preparing the environmental and engineering studies for
the project.
The Shoshone Hydroelectric Plant complex has provided power for the
citizens of Colorado through more than 70 years of uninterrupted service.
Originally, most of the power generated at Shoshone was transmitted over
the mountains to Leadville and to Denver on a 90,000 volt transmission
line.
This line is still in service today with a 115,000 volt capacity
but most of the power from Shoshone is now utilized on Colorado*s western
slope.
A second transmission line of 69,000 volts serves the Glenwood
Springs area and ties into a broad western slope transmission network.
In
addition, the Shoshone plant has a 13,000 volt distribution line which
serves the dam site, the White River National Forest rest area east of the
dam, and the Denver and Rio Grande Railroad in Glenwood Canyon.
This
distribution line also provided power to the few residential and commercial
■ ^■e-:.Tflts
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 3)
buildings located within the canyon.
These buildings have now been removed
as part of the Interstate highway construction project.
The Shoshone complex is significant for a number of reasons.
First, it is
one of the earliest hydroelectric plants of any consequence built along
the Colorado River.
More significantly, construction of the complex in
the depths of Glenwood Canyon was a remarkable engineering accomplishment
in terms of the physical difficulties encountered and the scale of the
undertaking.
Finally, the Shoshone Plant is one of the largest plants in the
Rocky Mountain region which depends upon the flow of a river for its source of
power rather than on the stored water of a reservoir.
In accordance with Section 800.3 of the Advisory Council on Historic
Preservation Regulations, the effects of the Glenwood Canyon project on
the Shoshone Hydroelectric Plant complex were evaluated.
It has been
determined that construction of Interstate 70 through Glenwood Canyon will
alter the surrounding environment and the setting of this historic resource
and, therefore, will have an adverse visual effect.
To mitigate this
effect, recordation to National Architectural and Engineering Record
standards was prescribed.
Historical Background
In June, 1903, the Colorado Power and Irrigation Company was organized
"to furnish electrical power to the various towns in the western part of
the state..."
A new hydroelectric plant was to be constructed at Shoshone
Falls in the canyon of the Grand River (later called Glenwood Canyon).
Glenwood Springs, located eight miles west of Shoshone Falls, had built its
own small hydro plant in the summer of 1886, but the canyon project was
on an entirely different scale and would provide power for a much larger
2
market.
Colorado Power and Irrigation never got its Shoshone Falls project off the
drawing board, but the idea and location passed on to the Central Colorado
Power Company which incorporated in November, 1906.
Central Colorado
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 4)
Power began construction before the end of 1906 and completed most of the
work in 2% years.
Development of the Shoshone complex involved four major construction
projects:
the main hydro plant itself, a water diversion tunnel, a
diversion dam, and a power transmission line.
In addition, a small 1000
horsepower generating plant was built on the north side of the river just
below Shoshone Falls to provide limited electrical power during construction of the main plant.
4
complex was completed.
This first plant was removed after the Shoshone
The Shoshone Hydro Plant complex was designed to take advantage of the drop
in elevation through the central part of Glenwood Canyon.
Water was to
be diverted from the river just above Shoshone Falls and delivered to
the plant through a long tunnel drilled in the north canyon wall.
Original company plans called for construction of a 12.9-mile tunnel and
pipeline extending from just east of the falls to a storage reservoir
4.8 miles west of Glenwood Springs (see Appendix A, Figure 1).
Economic
problems forced Colorado Power to reduce the scale of their project considerably and settle on a "temporary" location for the plant within the
5
canyon.
Construction on the diversion tunnel began in January, 1907, and required
two full years to complete.
To facilitate this labor, eight adits were
driven into the canyon wall to allow work to proceed from both ends and
at eight intermediate points along the way.
1915.)
(A ninth adit was driven in
When completed, the tunnel was approximately 12,450 feet long and
averaged 13 feet in height by 16'8" in width.
The floor and sides were
lined with concrete to reduce friction and turbulence, and in places
where the rock was weak or fractured a concrete arch was built as well
(see Appendix A, Figure 2).
The tunnel was constructed with a very low
hydraulic grade and had an original capacity of 1250 cubic feet per
second.
In 1929 the capacity was increased to 1408 cubic feet per second
by forcing air into the tunnel through Adit #2.
Air pressure reduced
wave motion in the tunnel, further reducing friction and turbulence.
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 5)
Construction of the 245-foot wide Shoshone Intake Diversion Dam began
during 1907 and was completed in the spring of 1910.
The original dam
was a complex "bear trap" structure designed to release excess water near
the river bed level through a series of large V-shaped wooden gates.
These gates, or "bear traps", formed the central part of the dam and were
supposed to lift up through the combined effect of water pressure and an
overhead hoist system (see Appendix A, Figure 3, and the detail of Section
7
A-B).
When the traps were elevated, the dam was closed; when lowered,
water was allowed to pass through.
Apparently this bear trap system was never effective, and required
modification almost immediately.
The first modifications occurred as
early as 1911 and have continued to the very recent past.
The bear traps
were finally removed beginning in 1930 and replaced with far more efficient
radial arm taintor gates (see illustration below).
The present dam has
four taintor gates and two heavy wooden flash board gates made up of
removable sections.
The flash boards are removed by use of an overhead
o
hoist and appear to be original features of the dam.
Cross Section: Radial Arm Taintor Gate
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 6)
In spite of these river control modifications, the dam continues to serve its
original purpose of deflecting water from the Colorado River into the diversion
tunnel.
Most hydroelectric plants in this country rely on a stored capacity of
water such as a reservoir or natural lake as a source of power rather than on
the normal flow of a river.
At Shoshone, the river backs up behind the dam,
creating a holding pond which eliminates daily fluctuations in water capacity
used for hydroelectric power generation.
9
variations in power.
This does not eliminate seasonal
Construction of the power plant itself appears from early photographs to have
been completed in early 1909.
The original plant was a simple 138x32 foot steel
framed structure which housed two 9,000 horsepower Francis turbines and two
5,000 kilowatt alternating current generators.
Water was directed from the
end of the diversion tunnel to the turbines through two 9-foot diameter steel
pressure pipes, or penstocks.
measure 287 feet in length.
The original penstocks are still in place and
The static head or drop in elevation from the
tunnel to the generators is 165 feet (see Appendix A, Figures 4 and 5).
Operations at the new plant began in late spring 1909, though some uncertainty
exists over the exact date.
In 1910, the first full year of production, the
Shoshone plant generated 38,096,600 kilowatt hours of electricity, far below
its projected power rating of 90,000,000 kilowatt hours.
Several modifications
have increased the plant's output to about 104,000,000 kilowatt hours £er year.
To carry its generated electricity across the state, Colorado Central Power
erected a 153-mile transmission line from the Shoshone plant to Denver by
way of Leadville, Georgetown and Idaho Springs.
Springs.
A second line ran to Glenwood
About 37 miles of the Denver line were completed east of Leadville
in 1907, and the entire line to Denver was finished by late 1908 or early 1909.
After rising more than 1500 feet from the canyon floor, the line crossed some
of Colorado's most rugged terrain, including Hagerman Pass (12,055 feet),
Fremont Pass (11,346 feet) and Argentine Pass (13,532 feet).
When it was
completed, the Shoshone line was the highest transmission line in the world.
Today the alignment remains essentially the same as the original, but the
transmission towers have been replaced, and the entire network has been
13
significantly altered.
12
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 7)
During the nearly 2% years of peak construction activities, Central
Colorado Power employed between 1000 and 1500 men.
Most of these employees
were housed at a large camp in the canyon built just east of the dam site.
The camp was called Shoshone.
Shoshone was originally a railroad siding
and small construction camp on the south side of the river built by the
Denver and Rio Grande Railroad during the late 1880s.
Central Colorado
Power erected buildings on both sides of the river with the vast majority
of structures on the north bank (see Appendix A, Figure 6).
The power
company provided housing, meals, medical care, a post office, apartment
units for married workers, and even a school for employees' children.
A
large receiving warehouse was built on the south side of the river near the
railroad depot, and the Colorado Provision Company, a subsidiary of
Central Colorado Power, built a large company store on the north shore
among the bunk houses.
A two-span through truss bridge crossed the river
at the east end of the camp to provide easy access back and forth.
Like
many other construction boom camps, Shoshone quickly faded when the work
14
was done. Today, nearly all traces of the camp have disappeared.
While construction activities were under way in the canyon, and for several
years after the plant began operations, the only road through Glenwood
Canyon was the primitive Taylor State Road constructed on the north side
of the river between 1899 and 1902.
It was narrow and rough and was
closed to all traffic through most of the winter and during periods of
high water in the spring.
The condition of this road forced Central
Colorado Power to bring in most of their equipment, food and supplies by
railroad and transport it across to the north shore on an overhead cable.
One cableway with a 558-foot span was erected beside the power plant, and
a second cableway with a 351-foot span was erected above the dam.
When construction activities ended, Central Colorado Power built housing
at the hydro plant and dam site for workers who operated the complex yearround.
From the beginning, a large bunk house and an apartment house were
in use at the plant, and a small house and garage were built for the
chief operator at the dam.
Sometime around 1920 two small houses were
built along the river just east of the plant for the Shoshone Hydroelectric
Plant superintendent and his chief operator.
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page S)
Changes at the hydro plant have occurred continuously through the years
but have not substantially altered the general appearance, setting or
historical importance of the plant.
Almost immediately after operations
began in 1909, a machine shop was constructed onto the east end of the
plant.
A lean-to shaped washroom (now a washroom and lunchroom) was
added onto the east side of the machine shop in 1935, and several support
buildings were built and moved around the outside of the plant in the
early years.
Sometime before 1920 the roofline of the main plant was
modified to provide a row of ventilation louvers, and two small horse
barns fell victim to the automobile age and were torn down.
In the late
1930s, when the Glenwood Canyon highway was substantially widened and
paved, the boarding house was torn down, the two houses at the plant
and the single house at the dam were moved away from the complex, and a
new office building/garage was built on the west side of the plant.
In
1963 the old apartment house was torn down to make room for a new 115,000
volt substation which stands on a small terrace west of the office
building.
Central Colorado Power's financial problems not only resulted in construction
of a "temporary" plant at Shoshone but ultimately led to foreclosure
in 1913.
At the same time that construction was underway in Glenwood
Canyon, the company was at work on* even larger hydroelectric projects in
Boulder Canyon and Gore Canyon (both in Colorado) and had a number of
survey crews in the field on other projects.
Overexpansion and rapid
expenditure of capital forced a financial reorganization.
On April 2,
1913, the Colorado Power Company was created and absorbed the assets and
properties of Central Colorado Power, including the Shoshone hydroelectric
-.
18
complex.
The Colorado Power Company retained owernship of the Shoshone Hydro Plant
for eleven years and directed many of the changes described above.
In
September, 1924, Colorado Power merged with the newly formed Public Service
19
Company of Colorado.
Public Service retains ownership today.
In spite of the modifications made to the complex, the hydro plant, dam
and diversion tunnel retain much of their original integrity.
of the structures at the plant and dam site follows-.
A description
Boundaries for the
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 9)
historic complex and building locations are shown on the three maps in
Appendix B.
Shoshone Complex:
Brief Description of Buildings and Structures
(Refer to Maps 1, 2 and 3 in Appendix B for structure location and identification.)
„ . .
.
MAP #1:
Shoshone Intake Diversion Tunnel (1907-1909).
The diversion tunnel extends
from just east of the Shoshone Diversion Dam to a point immediately above the
power plant, a total distance of 12,453 feet.
A profile study of the tunnel
conducted in 1924 recorded a very irregular ceiling height varying from 11*4"
to over 17 feet, with an average height of about 13 feet.
and the floor and lower walls are lined with concrete.
of the tunnel ceiling is also completed in concrete.
The width is 16'8"
Approximately 15%
The tunnel functions on
gravity flow and was constructed with a .06% grade from the diversion dam
to the forebay.
abandoned.
Of the nine adits drilled into the tunnel, three have been
Adit #6 serves as the main access to the tunnel for maintenance
repairs and clean up and Adit #2 houses the two air compressor units which
force air into the tunnel, thereby increasing the water carrying capacity of
the tunnel and the electrical generating capacity of the hydro plant.
MAP #2:
A.
Shoshone Hydroelectric Plant (1908-09).
The main building of the complex
is a steel framed structure with sheet metal siding supported by a concrete
foundation and floor.
The entire structure measures approximately 225 by 36
feet and stands about 27 feet high at the top of the roof.
The western two-
thirds of the building houses the turbines and generators, the electrical
control room and switchboard, circuit breakers, carrier cabinets, relay
equipment, and some storage areas.
Over the years the windows on the south
facade of this part of the hydro plant have been increased in size and now
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 10)
extend from just above ground level to just below the roofline.
The eastern
third of the building consists of two additions easily defined by the varied
roofline.
The first was added on to the main plant before the end of 1909
and houses a machine shop.
The second was built in 1935 as a washroom,
electrical shop and warehouse.
into a lunch room.
The electrical shop has since been converted
Behind the plant to the north is a small open courtyard
in which the 69,000 volt substation and the 13,000 volt distribution line
are located.
A poured concrete retaining wall stands 15 to 19 feet high along
the canyon wall and was built in 1946.
B.
Garage (below) and Office Building (1937).
This is a simple wood sided
two story building with a five bay garage below and office space above.
The
second story is divided into a large assembly room on the west, an office and
files area in the southeast corner and a restroom and kitchen area located
in the northeast corner.
The building was constructed in 1937 and replaced
an earlier single story garage which was torn down during the U.S. Highway 6
construction in 1937.
C.
115 Kv Substation (1963).
The 115,000 volt transmission line substation
was built on the site of the original hydro plant apartment house (1909).
This large two story building was torn down in 1963 and a concrete pad was
poured on the terrace above and west of the office building.
The old 115 kv
substation was removed from the west end of the hydro plant and rebuilt on
the pad.
D.
It is surrounded by an eight foot chain link fence.
Storage Building/Garage (1978).
This double bay garage was constructed
in 1978 of poured concrete with a reinforced concrete roof.
An earlier wood
garage built on this same location collapsed after rocks tumbled down the
canyon wall onto the roof.
The rock wall to the east of the garage was
rebuilt in 1978.
E.
Twin Penstocks (1908-09).
The penstocks are original and measure 287
feet in length and 9 feet in diameter.
They transfer water from the forebay
to the turbines with a 165 foot drop in elevation.
The upper one-third of
the penstocks are now buried to protect against falling rocks.
Shoshone Hydroelectric Plant Complex
HAER No. CO-S
(Page 11)
F.
Forebay (1908-09).
The forebay measures approximately 18 feet wide by
12 feet deep and is built back into the north canyon wall where it joins
the end of the water diversion tunnel.
The east, west and north walls are
of granite with wood and concrete walls extending out beyond the canyon wall.
The south wall of the building is wood siding above a concrete foundation.
An 8 foot high concrete wall rises above the forebay to deflect falling rocks
and prevent them from rolling onto the penstocks.
Inside the forebay are
two water control gates to the penstocks and the electrical motor which controls
them.
G.
The original wooden gates were replaced with steel gates in 1925.
Hoist House (c. 1907).
The hoist house is a small wood frame building
with sheet metal siding set on a concrete foundation and floor.
Inside is
the electrical motor which controls the 558 foot cable which stretches from
the hoist house to the south cableway tower across the Colorado River.
Both
the north and south A-frame cableway towers were rebuilt in 1940.
H.
Compressor Building (c. 1914).
This building houses an air compressor
used for maintenance purposes and as a backup source of air pressure for the
governor controls on the turbine generators.
The building appears to be a
small six foot square wood sided building but it actually extends about four
feet back into the granite canyon wall.
The exterior portion of the structure
stands on a raised concrete pad.
I.
Blacksmith Shop (c. 1914).
This is a small 16 by 8 foot wood frame
building with sheet metal siding and a gently sloping lean-to roof.
large windows on the west side provide lighting.
Three
Blacksmithing activities
ceased long ago and the building is now used for storage.
A rectangular
storage rack for metal pipe is located beside the blacksmith shop.
J.
Oil House/Flammable Storage Building (1939).
rectangular storage shed with sheet metal siding.
This is a small 6 by 8 foot
Gasoline, turbine oil and
other flammable liquids are stored here.
K.
Spillway (1915).
The spillway is an open steel trough with a ten foot
diameter which allows excess water in the tunnel to overflow before reaching
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 12)
the forebay.
The large concrete and wood box at the base of the spillway is
a loading and unloading dock used with the overhead cable system.
A long
metal stairway beside the spillway provides access to the hoist house, forebay
and potable water storage tank located above the plant.
The original spillway
(1908-09) was an 8 foot diameter wooden flume built just ten feet to the east
of the present spillway.
MAP #3:
L.
Shoshone Intake Diversion Dam (1907-10).
The Shoshone Dam measures
approximately 245 feet in length where it crosses the Colorado River near
the Denver and Rio Grande Railroad's Tunnel Number 2.
and stands 20 feet above the stream bed.
The dam is concrete
It is supported by pilings driven
30 feet and more into the sand and gravel and has a broad concrete apron
extending downstream.
There are six river control gates in the dam, four
radial arm taintor gates and two wooden flash board gates.
The flash boards
are comprised of individual sections which are lifted out of the face of the
dam by using a large hook connected to the overhead cableway.
that this system is original to the dam.
the dam since at least 1911.
It appears
Repair work has been ongoing at
Major reconstruction of the piers occurred in
1930, 1942, 1946, and 1952-53 and the concrete apron below the dam was
rebuilt in 1952-53.
Replacement of the original and ineffective bear trap
flood control gates occurred in 1930, 1937 and 1951.
An original through
truss footbridge built on top of the dam was removed beginning in 1930 and
the present walkway was completed in 1940.
M.
Gate House to the Diversion Tunnel (c. 1924).
The gate house is a cinder
block structure with a sheet metal roof built back into the granite north wall
of the canyon.
Within the building are the four control gates which regulate
the flow of water entering the diversion tunnel and the hydraulic controls
which operate them.
All electrical controls for the dam complex are located
in the building and there is a motor generator set which provides emergency
backup electric power for the dam.
This set consists of a 6 cylinder Ford
industrial engine fired by propane and a 220 volt generator.
The present
gate house may have been built around 1924 when the first mechanical trash
rakes were installed in front of the tunnel gates or in 1926 when the original
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 13)
wooden tunnel gates were replaced with steel gates.
Trash rakes clear
debris away from the large metal screens, or grizzlies, placed across the
entrance to the gate house and tunnel.
Large floating objects like trees
and branches are deflected away from the grizzlies by a floating trash
boom which angles across the front of the gate house to the corner of the
dam.
The present trash boom was floated into place in the spring of 1944.
Inside the gate house there is a small glass enclosed office used by the gate
tender on duty.
N.
Transformer and Switch Rack (Rebuilt, date unknown).
13,000 volts of
electricity are distributed from the Shoshone Hydro Plant to the transformer
at the dam complex.
The switch rack steps this voltage down to 440 volts
used by the Denver and Rio Grande Railroad across the river and to 220 volts
for use at the dam site and the rest area east of the dam.
0.
Hoist House and Cableway (1907).
This small sheet metal building houses
the electrical hoist motor and the ^controls for the overhead cableway.
The cable system stretches approximately 300 feet between the anchor point
on the north canyon wall and a cableway tower south of the river.
The cableway
system may well have been rebuilt in 1940 when the cable system at the power
plant was replaced.
Engineering records do not indicate if or when the cable
system at the dam was replaced.
The cableway is used for removing the flash-
boards from the dam and for clearing out trees and branches from behind the
dam.
P.
Steam Cleaner Building (c. 1930).
This small wood framed building has
corregated slate siding and an asphalt shingled roof.
It houses an electrical/
propane-fired steam cleaner used for melting ice off the Number 1 taintor gate
located at the north end of the dam.
During periods of cold weather when ice
freezes on the dam the steam cleaner is used to thaw out the first gate so
that excess water can be released from behind the dam.
Q,
Restroom Building (c. 1930).
The restroom building is a small square
wood framed building with corregated slate siding and an asphalt shingled
roof.
A self contained chlorine treatment leaching field is used for
sanitation.
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 14)
Footnotes
1. "Another New Power Plant,11 The Denver Times, June 19, 1903, p.2.
The name of the Grand River was changed in 1907 to the Colorado River by
the Colorado Legislature. This change was not officially recognized by
the U.S. Government until July, 1921. The name of the canyon was
changed to Glenwood Canyon by a resolution of the Board of Garfield County
Commissioners in 1914 and was accepted by the U.S. Government two years
later.
(Erlene Durrant Murray, Lest We Forget: A Short History of
Early Grand Valley, Colorado, Originally Called Parachute, Colorado.
Grand Junction, Colo.: Quahada, Inc., 1973, p. 1; Lena M. Urquhart,
Glenwood Springs: Spa in the Mountains. Boulder, Colo.: Pruett Publishing
Company, 1970, p.124.)
2. Lena M. Urquhart, op. cit., p. 48; E. C. LaRue, Colorado River
and Its Utilization, U.S. Department of Interior, U.S. Geological Survey,
Water-Supply Paper 395. Washington: Government Printing Office, 1916,
pp. 169-174; Ralf R. Woolley, Water Powers of the Great Salt Lake Basin,
U.S. Department of Interior, U.S. Geological Survey, Water-Supply Paper 517.
Washington: Government Printing Office, 1924, pp. 64-108. The power rating
of the Shoshone plant was projected to be 18,000 horsepower, larger than
any other hydro plant in the Colorado River Basin at that time.
3. Public Service Company of Colorado, "Facts About Shoshone",
informational brochure, 1975.
4. Central Colorado Power Company, "Report of Progress - October 1st,
1908." Denver: the Carson-Harper Co., 1908. Water was diverted from
the Grand River to the plant through a long six-foot diameter pipe
erected on the north bank of the river.
5. Public Service Company of Colorado, Electrical Engineering Files
and Records Room, 5525 East 38th Avenue, Denver, Colorado: Shoshone
Hydro Plant files, maps and photographs; Central Colorado Power Company,
op. cit., pp.13-15. The Shoshone Plant is shown on Figure 1, Appendix A,
as Glenwood No. 1 Power House near the top right corner of the map. The
proposed Power House No. 2 is located in the bottom left corner of the
map.
As late as 1908, Central Colorado Power was committed to extending
the tunnel "a considerable distance down the river" beyond Shoshone, but
just how far is unknown. In December, 1908, there were published reports
in the Glenwood Springs Daily Avalanche that the company planned to keep
750 men at work through the winter of 1909-10 extending the tunnel 1.2
miles west to Grizzly Creek. Although this work was never done, the idea
of building a new power plant at Grizzly Creek resurfaced in the late 1920s
when serious consideration was given to replacing the Shoshone plant.
Construction plans called for extending the tunnel 7,500 feet west and
construction a reservoir upstream on Grizzly Creek. A new plant with more
than twice the generating capacity of Shoshone would have been built along
the Colorado River. ("Grizzly Creek Hydro Power Project," Public Service
Company of Colorado, unpublished company report in the Shoshone Hydroplant
Files, November, 1929.)
The existing plant was apparently built as a temporary solution to
financial problems facing the company which may explain its steel frame and
sheet metal siding construction. The company definitely planned to discontinue
operations at Shoshone after a new hydro plant was completed farther down
the river and either sell off the old equipment or use it elsewhere.
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 15)
6. Central Colorado Power Company, op. cit., pp. 9, 13; Public Service
Company, "Facts About Shoshone," op. cit.; Public Service Company,
Electrical Engineering Files, op. cit.; Interview, Bill Neil, Shoshone
Hydro Plant, Maintenance Foreman, July 30, 1982. The actual drop in
elevation from the tunnel floor at the dam to the tunnel floor above the
power plant is only eight feet. Compressors located in Adit Number 2
force the air into the tunnel.
7. William P. Creager and Joel D. Justin, Hydroelectric Handbook.
New York: John Wiley and Sons, Inc., 1927, 1950, p.512. Public Service
Company, Eletrical Engineering Files, op. cit.; Interviews, Chuck
McClain, Shoshone Hydro Plant, Supervisor of Production, November 14, 1979
and July 28-30, 1982. The crib dam which shows on the original engineering
drawings (Appendix A, Figure 2) was built to prevent water from seeping
along the sand and gravel river bed to the permanent dam. While this helped,
it was necessary to dig a deep trench under the permanent dam to drain water
away while the concrete was drying. To keep the concrete from freezing
during winter construction, a huge tent was erected over the dam. These
were only a few of the many complex engineering problems encountered and
solved during construction. (E. L. West, unpublished memoirs in the
collection of the Boulder Hydroelectric Plant, Boulder Canyon, Colorado.)
8. Interviews, Chuck McClain, op. cit., July 28-30, 1982; Interview,
Jack Carrington, former Shoshone Hydro Plant Operator, Glenwood Springs,
Colorado, July 30, 1982. Mr. Carrington reported that sections of the
old bear trap dam were still in place in 1943 when he went to work at
Shoshone,
9. Public Service Company, "Facts About Shoshone," op. cit.; Interview,
Chuck McClain, op. cit., November 14, 1979. Although the dam does back
the river into a considerable holding pool, it does not create an actual
reservoir. During periods of low water each winter the entire flow of
the river is diverted through the tunnel to drive a single turbine at
the plant. In spring and summer there is enough volume to drive both
turbines at the plant and still allow excess water to spill over the dam.
(Public Service Company of Colorado, "Serving Colorado Over Sixty Years:
Shoshone Hydroelectric Plant," informational brochure, n.d.)
10. Central Colorado Power Company, op. cit., p. 13; Public Service
Company, Engineering Files, op. cit. Photographs of the plant and dam can
be found at the Public Service Company in Denver and at Shoshone, the
Western History Collection of the Denver Public Library, and the Stephen
H. Hart Library of the Colorado Historical Society.
11. LeRoy R. Hafen, ed., Colorado and its People: A Narrative and
Topical History of the Centennial State, 4 vols. New York: Lewis Historical
Publishing Co., Inc., 1948, Vol. I, p. 580; Public Service Company,
"Facts About Shoshone," op. cit. Public Service Company records
indicate the plant may have gone on line on June 6, 1909. Hafen sets
May 24, 1909 as the date Shoshone began generating power. It is possible
that the earlier date was a system test prior to actually producing
power for transmission and commercial use.
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 16)
12.
1979.
Interviews, Chuck McClain, op. cit., November 14 and December 12,
13. "Public Service Company of Colorado Centennial," Lines, Vol. 34,
No. 10 (November, 1969), p. 43; Central Colorado Power Company, op. cit.,
pp.21-23. In 1981 the eligibility of the Shoshone transmission line for
inclusion on the National Register was investigated. It was determined
that while the route of the line was historic, all towers, lines, and
other physical remains had been changed several times through the years.
Today's transmission line represents modern technology and is therefore
not eligible to the National Register. (Interview, Dr. Floyd Patterson,
Director, Cultural Resources Consultants, Denver, Colorado, September 15,
1982. Dr. Patterson did the research for the determination of eligibility.)
14. Colorado Department of Highways, Map Files, Denver, Colorado, Denver
and Rio Grande Railroad Valuation Maps, Map V-8-A, Sheet 13, June 30,
1919; William H. Bauer, James L. Ozmont and John H. Willard, Colorado Postal^
History: The Post Offices. Crete, Nebraska: J-B Publishing Company, 1971,
p. 119. As late as 1919 the railroad camp at Shoshone had telegraph and
freight offices, bunk houses, a tool house, depot,and a 16x24-foot water
tower. The post office was only open during the years of peak construction
in the canyon, from September 3, 1907 through June 30, 1910. Today there
are some stone foundations on the north side of the river above the present
roadway and some concrete foundations and low stone walls south of the
river. The old truss bridge was removed in the 1960s.
15. Lena M. Urquhart, op. cit., pp. 122-124; Bob Campbell, "Road
Building Was Lot Simpler 50 Years Ago," in Colorado West, the Sunday Magazine
of the (Grand Junction, Colorado) Daily Sentinel, March 18, 1973, pp.10-13;
Public Service Company, Engineering Files, op. cit. The condition of the
Taylor State Road forced Central Colorado Power to provide housing for its
employees within the canyon, first at Shoshone, and later on at the plant
complex. The first major improvement of the Taylor State Road was undertaken by the newly created State Highway Department. The job was completed
in May, 1920. The second major reconstruction occurred between 1936 and
1938 when the roadway was substantially widened and received its first
asphalt surface.
16. Interview, Chuck McClain, op. cit., November 14, 1979; Public
Service Company, Engineering Files, op. cit.
17. Public Service Company, Engineering Files, op. cit. The most
dramatic planned alteration of the Shoshone plant (aside from the original
plan to abandon it) occurred in the early 1940s when detailed- drawings were
prepared for construction of a brick and tile facade for the entire
main building. Like so many other plans for Shoshone, this work was
never begun.
18. LeRoy R. Hafen, op. cit. Vol. I, pp. 580-81; Central Colorado
Power Company, op. cit., pp.15, 19; Public Service Company, "Facts About
Shoshone," op. cit.
19.
LeRoy R. Hafen, op. cit., Vol. I, p. 581.
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 17)
APPENDIX A:
Shoshone Hydroelectric Plant Complex:
Engineering Plans
Note:
Figure 1:
Glenwood Power Canal and Pipeline (June, 1908)
Figure 2:
Tunnel Details (August, 1909)
Figure 3:
Headworks, Shoshone Intake Diversion Dam
(August, 1909)
Figure 4:
General Layout, Forebay and Penstocks
(November, 1908)
Figure 5:
Power House Arrangement (November, 1908)
Figure 6:
Key Map of Glenwood No. 1 Development
(April, 1907)
These 6 plans are included separately in the photograph
documentation for HAER No. CO-5 and are numbered CO-5-20
through CO-5-25 consecutively.
Shoshone Hydroelectric Plant Complex
HAER No. CO-5
(Page 18)
APPENDIX B:
Maps of the Shoshone Hydroelectric Plant Complex:
Building/Structure Locations and Site Boundaries
Map #1;
Shoshone Hydro Plant Complex:
Overview
Map #2:
Shoshone Hydro Plant and Surrounding
Structures
Map #3:
Shoshone Intake Dam and Surrounding
Structures
Shoshone Hydroelectric Plant Complex Map
HAER No. 00?5
K(Page 19)
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Shoshcaie Hydroelectric Plant
Complex
HAER NO. CO-5
Page 22
Photocopy o£ photograph (original print in the
Carleton L. Hubbard, Jr., Collection, Glenwood
Springs, Colorado)
John Schutte, Photographer, Circa 1914
SHOSHONE INTAKE DIVERSION DAM AND THE TAYLOR STATE
ROAD (LATER U.S. HIGHWAY 6)
(May not be reproduced without permission of Carleton
L, Hubbard, Jr.)
Shoshone. Hydroelectric Plant
Ccjriplex
HftER No. CO-5
{Page 23)
Shoshone Hydroelectric Plant Complex
Photocopy of photograph (original print in the Public
Service Company of Colorado, Denver, Colorado)
L. C. McClure, Photographer, Circa 1908
CONSTRUCTION OF THE INTAKE TO THE DIVERSION TUNNEL
(May not be reproduced without permission of the
Public Service Company of Colorado.)
Shoshone Hydroelectric Plant
/Corrplex
HAER NO. CO-5
(Page 24)
Shoshone Hydroelectric Plant Complex
Photocopy of photograph (original print in the Public
Service Company of Colorado, Denver, Colorado)
L. C. McClure, Photographer, Circa 1908
CONSTRUCTION OF THE INTAKE TO THE DIVERSION TUNNEL
(May not be reproduced without permission of the
Public Service Company of Colorado.)
Sho^hone Hydroelectric
/ Plant Complex
HAER No. CO-5
(Page 25)
Shoshone Hydro
Photocopy of photograph (original print in the Public
Service Company of Colordo, Denver, Colorado)
L* C. McClure, Photographer, Circa 1908
SOUTH ELEVATION OF THE SHOSHONE HYDROELECTRIC PLANT
BEFORE CONSTRUCTION OF THE FOREBAY
(May not be reproduced without permission of the
Public Service Company of Colorado.)
Shosjaone Hydroelectric Plafrt
' Complex
KAER No. CO-5
(Page 26)
Photocopy of photograph (original print in the Public
Service Company of Colorado, Denver, Colorado)
L. C. McClure, Photographer, Circa 1908
CONSTRUCTION OF THE SHOSHONE HYDROELECTRIC PLANT
(May not be reproduced without permission of the
Public Service Company of Colorado.)
Shoshone Hydroelectric
/ Plant Complex
HAER No. CO-5
(Page 27)
Shoshone Hydroelectric Plant Complex
Photocopy of photograph (original print in the
Frontier Historical Society, Glenwood Springs,
Colorado)
Photographer unknown. Circa 1907
CENTRAL COLORADO POWER COMPANY'S TEMPORARY POWER
PLANT LOCATED BELOW (WEST OF) THE INTAKE DAM,
VIEW TO THE NORTHEAST
(May not be reproduced without permission of the
Frontier Historical Society.)