fresh water
The Caloosahatchee River is a freshwater river.
The Ganges River is freshwater.
The Ohio river is fresh water.
delta
Yes, the Thames is a tidal river and can have both freshwater and saltwater at different times of the day. The saltwater from the North Sea mixes with the freshwater from tributaries, creating a brackish environment in certain parts of the river.
an estuary
Saltwater fish have a natural habitat in the sea. Whereas, freshwater fish has a habitat in a river or a lake.
they are both saltwater and freshwater
They contain saltwater and freshwater
Most are natural freshwater, but some may be saltwater.
The Persian Gulf is saltwater, not freshwater.
This area of water is known as an estuary.