RP: creating waterway=flume looks good
or perhaps we could extend waterway=canal? as the NHD import used
HB: nothing about waterway=flume in the osm wiki, so I created a proposal page for it:
HB: as long as folks are happy with waterway= instead of man_made=, it seems ready to go.
uploaded by HB for the mainland 14 Jan 2011 in changeset 6964811