text: i'd almost guess a pipeline based on how it appears with dg vivid.  bing z20 is probably some 5 years old; no other tms imagery i can access shows anything.  the naip layer that appeared this morning my time is wms and thus does not work directly in my editor.
  
  note that the nearly parallel pipeline some distance to the west shown on topo maps which i view in potlatch2 z14 dg vivid and wireframe, appears very similar from the air.