The illustration portrays the water cycle in two differenet types of areas, forested and urban.
Overall, the procedure seems to be identical for both areas. However, the main difference is the outocome of each phase and its success level.
When it comes to the forested areas, the trees enhance the total procedure as they filter the rain water. More specifically, the falling water penetrates both topsoil and subsoil, getting filtered. At the same time, the amount of water remaining in the surface of the soil evaporates to the atmposphere while the rest continues to flow filtered.
On the other hand, the absence of trees in the cities eliminates the hole procedure and results to an increased polluted runoff. From the very beginning, the falling water fails to get filtered, leading to a reduced baseflow and an icreased errosion of the sublayers of the ground. At the same time, the proportion of water evaporation is being decreased, while the waterdespairs polluted through the city.