A more thorough explanation:

An ancient watercourse is a type of watercourse that has existed from time immemorial. It refers to a natural channel that has been formed by the forces of nature and has been in existence for a long time. Examples of ancient watercourses include rivers, creeks, springs, lakes, and marshes.

For instance, the Nile River in Egypt is an ancient watercourse that has been in existence for thousands of years. It is a natural channel that has been formed by the forces of nature and has been used for various purposes such as irrigation, transportation, and fishing.

Another example is the Amazon River in South America, which is the largest river in the world by volume. It is an ancient watercourse that has been in existence for millions of years and is home to a diverse range of plant and animal species.

Overall, ancient watercourses are important natural resources that provide various benefits to humans and the environment. They are subject to state control and can be used for private purposes according to state law.