The diagrams depict the natural phenomenon, the water cycle, in a well-cultured area and the city area.
Overall, the five-step process is smoother and more natural in areas with plantations than in the urban areas, where the procedure is obstructed. A few steps are even missing in developed regions.
The water cycle commences with the rainfall in a particular area. In a forested region, the topsoil is permeable, which allows the water to infiltrate through it up to the water table. The surplus water runs off the surface, while few get trapped in the leaves of plants. The plant-trapped water is used by them and is returned back to the atmosphere by transpiration and evaporation. There is also baseflow through the less permeable subsoil on rock. This cycle continues as the returned water falls back after a certain time.
Similar to the planted areas, the cycle starts with precipitation in urban areas, but the infiltration is minimal. The baseflow is reduced, which increases erosion in the surrounding area. If the runoff occurs, the polluted water flows through the ground. Due to missing plants and vegetation, there is diminished transpiration and evaporation. However, the cycle is continued.