Wednesday, August 30, 2017

Water carriers

On the way from the John Hart Project parking lot to Elk Falls, the trail crosses the 1947 wood-stave pipes, still in use. They carry water for the city of Campbell River and the John Hart power station.

Three pipes, 12 feet in diameter each.

View downstream, from the bridge.

The pipes carry water for 1.1 kilometers, from the John Hart dam, below the outlet of John Hart Lake, to a shorter, high pressure, steel pipe leading in to the powerhouse, which empties into the Campbell River.

The dam was built in 1946-7, and provides electricity to the northern half of Vancouver Island (Nanaimo-Port Alberni tothe northern tip) The pipes and the generating station are in the process of being replaced, due to concerns over earthquake stability. During their construction, back in 1946, the area suffered a quake that measured 7.3 on the Richter scale, and the pipes were deemed strong enough to weather one like that back then. But that was 70 years ago.

The pipes will be removed by next year, and will be replaced by a tunnel through the bedrock, their channel infilled and reforested.

Wood stave construction: long, Douglas fir staves (bevelled boards, like those used to make wooden barrels), paint, and steel bands.

Occasionally, these pipes spring a leak. This bit looks like it has been patched with tar. Sometimes a steel plate is installed where boards have been broken through.

Stave wood pipes had the advantage of being pieced together somewhat like tongue and groove joints of staggered lengths, building a continuous pipe and lessening the number of joints. These pipes also swelled when soaked with water, forming tight seals. Tar was applied to the outside and the pipe was wrapped with metal bands to keep it stable. Interestingly, water coming from these pipes didn’t taste like wood since the tree sap was soon flushed out and thus the taste went with it. (Tri-State Museum)



2 comments:

  1. I had a double-take when I read wood pipes... Thanks for the informative post!

    ReplyDelete
  2. We hwv a pair of pipes like that here, feeding a small power plant. They are steel now, but I remember the old wooden pipes, built in 1914.

    ReplyDelete

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