Which gruiform birds are most closely associated with slow-flowing streams?

Within the order Gruiformes, the finfoots (family Heliornithidae) are the birds most closely associated with slow-flowing streams.1

These semiaquatic birds are known for their shy and secluded nature, typically spending their time in quiet, shady rivers where they remain half-submerged near overhanging banks. This dense, overhanging vegetation provides them with necessary cover. Their physical adaptations, such as lobed feet, allow them to swim effectively and clamber among the branches and fallen trunks found in these riverine environments.21