What is the difference between the appearance of the river and the surrounding area in the upper, middle and lower reaches?

In the upper course, the river is usually characterized by large slopes and correspondingly high speeds. In this part of the course, the river, as a rule, vigorously erodes its channel. In the middle and lower parts of the current, the slopes of the water surface and the speed of the current decrease, and the erosional activity of the stream weakens. In the middle part, the river brings in transit products of erosion brought from above. In the lower reaches, mainly the accumulation of erosion products from the upper parts of the river basin takes place.