1909 Shoshone Hydroelectric Facilities on the Colorado River

I rode Amtrak's California Zephyr through Colorado on Thanksgiving, 2019. One of the things I saw was obviously the penstocks for a hydroelectric power plant.

20191128 0742-60+30c

Satellite

From a satellite image, it is obvious that the two light brown penstocks on the left side of the photo above feed the turbines. I don't know what the dark brown penstock on the right is for. The two horizontal "brown lines" is I-70 plus US-6 plus US-24. The lower highway is the eastbound lanes and the upper highway is the westbound lanes. (A couple of "white spots" is glare off the observation lounge window.)

Photo from COLO,23-GLENS.V,1--4 from co0088
4. SHOSHONE HYDROELECTRIC PLANT, SOUTH ELEVATION; TWIN PENSTOCKS AND FOREBAY ABOVE THE PLANT; HOIST HOUSE AND NORTH CABLEWAY TOWER ABOVE THE SPILLWAY TO THE RIGHT; TAIL RACE BELOW U.S. HIGHWAY 6 BRIDGE. - Shoshone Hydroelectric Plant Complex, 60111 U.S. Highway 6, Garfield County, CO

Street View from the upper (westbound) I-70+US-6+US-24 lanes

Street View from the lower (eastbound) I-70+US-6 lanes

17. Photocopy of photograph (original print at the Public Service Company of Colorado, Shoshone Hydro Plant Collection, Glenwood Springs, Colorado) Photographer unknown, Circa 1935, cropped

18. Photocopy of photograph (original print at the Public Service Company of Colorado, Shoshone Hydro Plant Collection, Glenwood Springs, Colorado) Photographer unknown, Circa 1935, cropped

19. Photocopy of photograph (original print at the Public Service Company of Colorado, Shoshone Hydro Plant Collection, Glenwood Springs, Colorado) Photographer unknown, Circa 1940, cropped

It is a run-of-river plant that generates 15mw using two units. [Xcel] The intake diversion dam was built just east of Shoshone Falls.

Satellite

As I have seen in other places, the "falls" appears to be a rapids.

11. SHOSHONE INTAKE DAM, VIEW TO THE NORTHWEST. RESTROOM BUILDING AND STEAM CLEANER BUILDING ARE SEEN BELOW THE WEST SPAN OF THE BRIDGE; HOIST HOUSE AND CABLEWAY TOWER APE ABOVE CENTER. - Shoshone Hydroelectric Plant Complex, 60111 U.S. Highway 6, Garfield County, CO, cropped

12. SHOSHONE INTAKE DAM, VIEW TO THE NORTHWEST. WALKWAY ABOVE DAM ON THE LEFT; GATE HOUSE TO DIVERSION TUNNEL BELOW EAST BRIDGE SPAN; HOIST HOUSE ABOVE CENTER; TRANSFORMER AND SWITCH RACK ON THE RIGHT EDGE OF PHOTO, cropped

The above shot of the dam was cropped and exposure corrected. I thought it would be interesting to show what the raw version of the previous photo I took of the dam looked like. I took this one as soon as there was a break in the treeline, as did the person beside me.

Note that the gates are closed. It is no surprise that November would be a dry season for the Colorado River. I had noticed that the flow was almost gone in the river. When I noticed that, I said out loud "Where did the river go?" which was rather embarrassing. I took a photo of the very low flow in the river. The train was going rather slow through Glenwood Canyon, but a tree did manage to sneak into the foreground of this photo.

I took the photo below because of the bridge. But I now understand that we are seeing the upstream part of the 245' dam on the left. And the river is going under the bridge into 16'8" wide by 13' high diversion tunnel that was dug 12,450' through the mountain to the penstocks. The dam was originally built with bear trap gates, but they proved to be a maintenance problem so in 1930 they were replaced with four tainter gates. The dam also has flash boards that are believed to be part of the original construction. [historic-structures]

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. A second line ran to Glenwood Springs. 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 significantly altered. [historic-structures] It has become obvious that their source was HAER-data.

The original transmission line was 90,000 volts. That line has been upgraded to 115,000 volts, but most of the power generated is now consumed on the western slope. This HAER record was made in 1980 because the proposed I-70 construction would have "an adverse visual effect."  [HAER-data]

HAER-data, Map 1

Satellite

As seen in the above satellite image of the rapids and this image of the dam, the river is not always dry between the dam and plant. That is, sometimes the flow in the river exceeds what is needed to fill the diversion tunnel. I checked Bing Maps for river flow. The image of the dam is unusable because it is in the shadow of the canyon wall. But an image of the rapids shows the flow was very low. In fact, it is hard to see where the river is. I include the image at full resolution because Bing Maps would not give me a link.

(The "creating link" comment never was replaced with a link.)

This video shows a heavy flow downstream of the dam.
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The Moffat Tunnel is one of several diversion tunnels that have been built to carry water from the Colorado River Basin to the towns on the east side of the Rockies. But this power plant has water rights to what it originally could handle, 1250cfs. And because of the age of those rights, it has priority. During droughts, the managers of the intakes to the continental divide tunnels have to reduce their flow so that the power plant gets its flow. Because the plant returns all of its water to the river, these water rights provide water for uses downstream such as drinking and irrigation of peach trees. [HCN] This flow is also helps sustain "an important part of the local economy: rafting, kayaking and fishing." Maintaining a high flow in the river also helps dilute the salt coming out of salt springs, which of course benefits the farmers who use the water for irrigation. In fact, some farmers would like to buy the plant just to get the water rights. 15mw is a drop in the bucket compared to most power plants, but 1250cfs is not just a drop. "But Xcel continues to invest millions in maintenance at the plant and the utility says they have no plans to sell Shoshone or its water rights." [KRCC] The flow also helps save four endangered fish species. [InkStain]