Commentary Inf XVI 94-105

Dante, fond of the rivers of Italy as sources for poetic 'digressions,' describes the Acquacheta (its name means 'quiet water') as being joined by the Riodestro near its source in the Apennines, and then changing name (to 'Montone') at Forlì, before it flows into the Adriatic Sea just south of Ravenna without pouring first into the Po, the major river of the region. At its source at San Benedetto dell'Alpe, the meaning seems to be (and Petrocchi's text is much debated here), when the river was not in flood, forming the cascade referred to, it might have consisted in only a thousand rivulets. Phlegethon, descending into Cocytus, is here a waterfall resembling the Acquacheta in flood.

Perhaps mirroring the length of the river it describes, the simile here is the longest yet found in Inferno (the two closest challengers occur at [Inf III 112-120] and [Inf XV 4-12]; but the thirteen cantos of Malebolge will at first equal and finally outdo any other area of the poem for length of simile: [Inf XXI 7-18]; [Inf XXII 1-12]; [Inf XXIV 1-18]; [Inf XXVIII 7-21]; and the 'champion,' [Inf XXX 1-27]).