What is the tone and mood of "The Song of the Chattahoochee"?

This poem is written in the voice of the Chattahoochee river itself, as it describes its journey "out of the hills of Habersham." The tone of the poem is wistful: the river begins its journey in a beautiful place, where it would prefer to stay. All around it, it hears appeals from nature to remain on the high lands: "The rushes cried, 'Abide, Abide,' / The willful waterweeds held me thrall." Yet, the river's journey is not dictated by its own desires but by its ultimate purpose. It moves "with a lover's pain to attain the plain," which is its final goal.
As the river rushes through the high valleys, everything it passes, from the "ferns and the fondling grass" to the "little reeds" begs it to stay. The hickory tells, "fair tales of the shade," and the river finds itself held back by "the smooth brook-stone," which entreats him "with friendly brawl" not to pass out of the valley. The "lures" of the precious stones are appealing to the river; the juxtaposition between the lush descriptions of the upper valleys and the depiction of the "dry fields" below make clear that it would far prefer to linger in the place where it began.
Such is not for the river to decide, however. "Downward the voices of Duty call," and the river must somberly answer this call. Below, on the plain, it must provide water, help the mills turn, and respond to the "myriad flowers" which "mortally yearn" for irrigation. So, the river responds to its duty, despite the plaintive begging of the lush lands in the valley for it to stay there. The mood of the poem suggests that duty must ultimately be the river's guide, even if it causes "a lover's pain" to break away and pursue such a duty.