Which type of rock increases the rate of runoff?

The type of rock that increases the rate of runoff is impermeable rock. These rocks do not allow water to infiltrate their surface due to their dense and compact nature, which leads to greater surface water flow because rainwater cannot easily seep into the ground. As a result, the water accumulates on the surface, leading to faster runoff into rivers and other bodies of water.

In contrast, permeable rocks allow water to pass through them, which decreases runoff as water is absorbed into the ground. Igneous rocks can be either permeable or impermeable depending on their characteristics, and sedimentary rocks often have varying degrees of permeability as well. Therefore, impermeable rocks are specifically recognized for promoting higher rates of runoff as they prevent water from soaking into the soil.