A freshwater lake that is formed by a city damming a river is an example of an artificial reservoir.
Explanation:
A reservoir can be classified into the category of natural reservoirs or artificial reservoirs depending on their formation.
If the reservoir is formed due to the 'accumulation of water' in a naturally occurring depression, it is a natural reservoir.
On the other hand, if the reservoir is formed by damming the natural course of water flowing through a river or a stream, it is called an artificial reservoir.
