The diagram shows the water cycle process in both forested and urban areas. Despite their geographical differences, both environments follow the same overall flow, which is composed of six main stages.
To begin with, precipitation remains constant in the two environments, but what varies the most is the soil composition. Forested areas contain a thicker permeable topsoil, allowing smoother infiltration and preventing severe baseflow erosion. By contrast, urban areas have less permeable surfaces, which leads to increased polluted runoff and higher levels of erosion.
Focusing on the remaining stages, forested regions experience denser transpiration and evaporation, as water is absorbed by permeable topsoil and regulated by trees. Urban locations, on the other hand, lack this soil permeability and present a low density of vegetation consequently suffering from reduced transpiration, evaporation and infiltration. As a result, these combined factors contribute to higher levels of polluted surface runoff.