Compared to rural areas, cities have less infiltration and more runoff due to more impervious surfaces, compacted soil, and less vegetation. This can lead to flooding, water pollution, and groundwater depletion.
Compared to surrounding rural areas, urban areas have less infiltration and more runoff.
Here's why:
- Increased impervious surfaces: Urban areas have a higher percentage of impervious surfaces like buildings, roads, and parking lots. These surfaces prevent rainwater from soaking into the ground, increasing the amount of runoff.
- Compacted soil: Urban soil is often compacted due to construction and heavy traffic, which reduces its ability to absorb water.
- Lack of vegetation: Urban areas have less vegetation than rural areas, which reduces the amount of rainwater that can be intercepted by leaves and stems and slowly infiltrate into the soil.
As a result of these factors, urban areas have a lower rate of infiltration and a higher rate of runoff compared to rural areas. This can lead to several problems, including:
- Flooding: Increased runoff can overwhelm drainage systems and lead to flooding.
- Water pollution: Runoff can carry pollutants like oil, fertilizers, and pesticides into waterways, damaging the environment.
- Groundwater depletion: Less infiltration means less water replenishing the groundwater supply.
Therefore, it is crucial to implement measures to increase infiltration and reduce runoff in urban areas, such as planting trees, using green roofs, and creating rain gardens.