The wheels on the bus go round and round round and......flat -______________-

Hello people!!! I would like to inform you that the poem I will be doing my essay in is Clocks and lovers. why? I chose this poem because I actually understand this poem because we discussed it in class. I really like it but then the ending still confuses me because the clocks stopped chiming and the lovers left but the river kept on running. So then what is the river??? I guess i just need to figure it out. Oh and the author is W.H Auden.