What environmental benefit do vegetated swales provide in stormwater management?

Vegetated swales play a crucial role in stormwater management by effectively filtering pollutants and improving water quality. These landscape features are designed to manage runoff by directing it through vegetation, which helps to absorb and retain water while also trapping sediments and filtering harmful contaminants. The plants within the swales take up nutrients, heavy metals, and other pollutants from the water, thereby enhancing the overall quality of stormwater before it enters larger water bodies. This natural filtration process contributes to healthier ecosystems and reduces the burden on municipal water treatment systems.

In contrast, the other options do not accurately reflect the primary purpose of vegetated swales in stormwater management. While they may affect landscaping needs or have maintenance requirements, these are secondary to their main environmental benefit of pollutant removal and water quality enhancement.