What slope indicates strong surface drainage with no cover?

A slope above 9% indicates strong surface drainage with no cover due to several factors related to how water moves across the landscape. Steeper slopes facilitate the rapid movement of water away from the surface as gravity pulls it downward. This reduces the time water spends in contact with the soil, allowing for less chance of saturation and pooling.

In addition, steep slopes tend to have less vegetation and soil cover, which would otherwise slow down water movement and promote absorption. Without cover, any precipitation is likely to run off quickly rather than infiltrate the soil. This can lead to well-drained conditions where water does not linger on the surface.

In contrast, slopes that are gentler, such as those in the lower percentages, tend to retain more water, as the gradual incline allows for longer travel times for surface runoff. These slopes may also support more vegetation, which improves infiltration and can cause water to pool or saturate the area more readily. Therefore, a slope above 9% is distinctly characterized by its ability to promote rapid drainage, contributing to the identification of strong surface drainage conditions.