. _:b1216015 . "ENVO:00000148"^^ . "A shallow stretch of a river or stream, where the current is above the average stream velocity and where the water forms small rippled waves as a result. It often consists of a rocky bed of gravels or other small stones."^^ . _:b1216015 . "Wikipedia:Riffle"^^ . . _:b1216015 . "riffle"^^ . _:b1216015 . "EcoLexicon:riffle"^^ . "ENVO"^^ .