Flume - the title - is a word with a meaning not very common? Had to check it out in the dictionary. In the song you see "gluey feathers on the flume".
Maroon is a dark brown red colour? The text states: "Only love is all maroon". True or not true?

And one more sentence:
"Sky is a womb and she is the moon" which refers less to school knowledge and more to the truth of dreams and the patterns of subconsciousness.

In an interview Justin Vernon expressed the special importance of this song connected to dream spheres connected to him.

Mother and son and womb and flume and water and the moon in the sky which is mother? Remember the Salvador Dalí painting?

The maroon colour´s burnig rope´s reddish rouge or lapping lakes like leary loons leaving might give an idea what it is about?

The mesmerizing music of word clusters matching the music is originating from the old fashioned romantic campfire guitar touching the new age synthesizer´s sphere depicting a Sound-Mandala of marooned aspects of love.