Getting a stream to pass under a new canal? The term used locally is "chunker", and the conduits were made traditionally using elm planks to make some sort of a covering structure before the canal earthworks pass over the top of it. Elm chunkers have been known to last 200 years. It would be better these days to use something like polypropylene pipes or maybe even concrete these days, assuming that there were no heritage constraint applied to the operation that might prevent hese materials being used.
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