Which of the following is NOT a property of a river system?

Soil composition is not a property of a river system. River systems are primarily characterized by their hydrological properties and behaviors, which include streamflow, laminar flow, and turbulent flow.

Streamflow refers to the movement of water within the river, influenced by factors like precipitation and watershed characteristics. Laminar flow and turbulent flow describe the different types of water flow behavior within the river; laminar flow represents smooth and orderly movement, while turbulent flow indicates chaotic and irregular flow patterns.

In contrast, soil composition pertains to the characteristics of the soil in the surrounding environment rather than the behavior of the river itself. While soil can affect river quality and the landscape surrounding a river, it does not define the properties inherent to the river system, making it the correct choice for this question.