source / spring nacimiento: The source of the Tagus is in the Sierra de Albarracín.

headwater cabecera: The region is an important wildlife habitat and the headwater for the region's river.

(river) bank orilla: She was enjoying her walk down the quiet country lane towards the river bank. ^ There is intensive cultivation along the banks of the river.

riverside orilla, ribera: the riverside warehouses of the London docklands

backwater remanso: It was a peaceful and unspoilt backwater.

riverbed / bed lecho, cauce: There was a dried-up riverbed not far away, and along its banks were the skeletons of trees long dead.

sandbank banco de arena: The boat ran aground on a sandbank.

sand bar / sandbar barrera de arena, banco de arena: The Kumbukan river rises with the first rains and breaks down the sand bar between itself and the sea.

course curso: We went down the course of the river.

(river) basin cuenca: This year's winter storms dumped more rain south of the river basin. ^ the Mississippi river basin

rapids (plural) rápidos shoot the rapids bajar los rápidos: There were some rapids on a stretch of the river. ^ Come and shoot the rapids in a virtual prehistoric world.

torrent /ˈtɒrənt/ torrente: Again, a torrent of water had flooded the valley. ^ a raging/rushing torrent

waterfall (also falls plural) cascada, catarata, cataratas: the Niagara Falls

meander /miˈændə/ 1. meandro 2. serpentear: The river meanders through the city.

ford /fɔːd/ vado: They didn't know the location of the ford.

stream - brook - rill - beck - burn - creek

stream arroyo: The common frog usually lives near a pond or stream, and spends a lot of its time in water.

brook /brʊk/ arroyo [smaller than stream]: There was a brook in front.

rill (in northern England beck) arroyo, riachuelo: moorland rills

burn arroyo [small, in Scotland and northern England]: the battle of Bannockburn

creek (American English) riachuelo: A few hours later, the creek returned to its normal flow.

tributary /ˈtrɪbjʊtəri/ afluente: We crossed a fine iron suspension bridge spanning a northern tributary of the Irrawaddy.

confluence /ˈkɒnfluəns/ confluencia: On the last evening we camped on a bluff overlooking the Mississippi's confluence with the Wisconsin.

mouth desembocadura: They sat down at the end of the beach by the mouth of the river.

flow into desembocar en: The Ebro flows into the Mediterranean.

fluvial /ˈfluːviəl/ (technical) fluvial: fluvial waters