In the river tees is the upper course at the begining where the source is and the lower course where the mouth is? thanks

The upper course of a river is at the beginning.

See http://www.scalloway.org.uk/phyl2.htm and links at the bottom of that page for examples

thankyou it was very kind for you to help

Yes, that's correct. The upper course of a river refers to the section of the river that is closer to its source, typically in higher elevation areas such as mountains or hills. The lower course, on the other hand, refers to the section of the river that is closer to its mouth, where it meets a larger body of water like a lake, sea, or ocean.

To determine the location of the upper and lower courses of a particular river, you can follow these steps:

1. Identify the source of the river: This is the starting point of the river and is usually found in highland areas. For the River Tees, the source is Cross Fell in the Pennines mountain range in northern England.

2. Trace the river downstream: Follow the river's path on a map or use satellite imagery to track its route. As you move downstream, you'll notice the river growing in size as it receives water from smaller tributaries.

3. Locate the mouth: The mouth of a river is typically where it empties into a larger body of water. In the case of the River Tees, it flows into the North Sea near the town of Redcar in northeastern England.

By following these steps, you can accurately identify the upper course (near the source) and lower course (near the mouth) of the River Tees.