This is an archived article that was published on sltrib.com in 2007, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
On Mill Creek Canyon's Pipeline Trail, I have encountered scores of hikers, bikers, runners and dogs. But few of them know much about the now-gone pipeline that made the trail possible.
The trail is named after two wood pipelines that supplied water power to electricity-generating plants, one built near Porter Fork in 1907, and one at the mouth of Mill Creek Canyon, built a few years later.
Here's how it worked: Water flowed in the pipeline at a gentle grade, in and out of the canyons, until it reached a penstock high above the canyon. This penstock was made of riveted steel, and through it the water rushed down a steep hill to the generators.
The upper pipeline mainly supplied power to a brick factory in the Millcreek area. The lower pipeline supplied power to a smelter in Midvale. In 1912, Utah Power and Light Co. acquired the pipelines and plants. That's the general story. But there are fascinating details.
The stave pipe was a technology developed a few decades before, and in some ways it was appropriate for this project. Wood cost less than steel. It was also more flexible and forgiving, and it insulated from freezes better than steel. Crews could more easily transport the materials for wood pipes up steep mountains, and they could repair it with local materials.
To make the pipe, workers laid a U-shaped form, then used it to lay the bottom half of the pipe using staves milled to form a cylinder. Each stave was joined to the next with a steel plate inserted in a groove in the ends. The crews then used another form to lay the top half of the pipe. They circled the completed pipe with thick wire bands secured by metal shoes and tightened with a nut. You can still see remnants of these bands and shoes on the trail.
The upper pipeline was 22 inches in diameter, made of California redwood, and was buried. The lower pipeline was 30 inches, made of Douglas fir, and built on top of the ground.
The pipe curved in and out of the contours of the canyon. Where the curves were tight, a steel elbow was required, and you can still see a few on the trail.
At the end of the Overlook Trail at the mouth of the canyon, hikers can see a riveted steel Y that connected the pipe to the penstock, where the water flowed steeply down to the generator. One arm of the Y connected to the wood pipe bringing water down the canyon. The lower arm of the Y was connected to the riveted steel penstock. The other arm connected to another wood pipe that ran uphill as a vent pipe to help regulate pressure and prevent bursting. When the water pressure grew too high, excess water would flow up this pipe. You can still see the gully caused by the overflow water.
A wooden pipe works well when the water flows consistently and at a high enough flow to keep the wood saturated, thus preserving the wood. If the wood is not kept saturated, it rots from the dampness, and this is what happened to the Mill Creek Pipeline. Fluctuations in power demand as well as in supply led to deterioration of the pipe, and it became unsafe to use. Therefore, the lower of Mill Creek Canyon's two power plants closed in 1949; the upper plant actually operated until 1970.
Traces of the past lie all around us. Knowing about these traces makes my experience on the land mean so much more. Hope it does for you, too.
* KRISTEN ROGERS-IVERSEN can be reached at firstname.lastname@example.org.
The source for this information is William T. Parry's excellent study, The Mill Creek Canyon Wooden Pipelines.