How does the volume of rainwater runoff affect the streams?
Oregon Creek during a storm It’s not only the quality of the runoff that can degrade the streams but also the amount of water. In an undeveloped watershed with entirely natural vegetative cover, most rainfall and snowmelt can soak into the soil before entering the streams and so the increase in flow is much more gradual than in a watershed with lots of hard, impervious surfaces such as roofs, roads and pavement. The water gets into the streams faster, and the increased volume results in higher stream velocities. This increases stream bank erosion and potential for flooding.
