what do the two rivers symbolize

There were two separate worlds going on in "A Separate Peace". There is the world of WW2 and the world of Devon prep. School. The Nagussett symbolised the war and the Devon River symbolised school. While the Devon River was familiar to the students the Naguessett was foreign and ominous. They had "...never used this lower river, the Naguamsett. It was ugly, saline, fringed with marsh, mud and seaweed." As the story progresses, at least for Gene and Finny, the meanings of the two rivers converge somewhat. The guilt and shame surrounding Finny's accident (in the Devon River) take on unfamiliar territory. The feelings are ugly, muddy and uncertain.