Wellll.... from my observations, many of the Anthuriums from Sect. Belolonchum grow as riparians; IMHO these are among the nicest of them in terms of leaf size and shape, and also in terms of brightly coloured inflorescences. A. giganteum is a good place to start. Also, as Dr. Croat mentions in his note above, members of the Sect. Calomystrium are often riparians. Best of luck!