Which is an example of an infiltration practice?

• A. Detention basin
• B. Infiltration trench
• C. Vegetated swale
• D. Sand filter

Answer: (B)

Infiltration practices are designed to allow stormwater to move into the soil, reducing runoff and helping recharge groundwater. An infiltration trench is built specifically for this purpose: it’s a shallow trench filled with gravel and a perforated pipe that collects runoff and promotes downward infiltration into the surrounding soil. This directly fulfills the goal of infiltrating water, unlike other options. A detention basin is meant to store water temporarily and release it slowly without significant infiltration. A vegetated swale mainly serves as a conveyance and treatment feature, with any infiltration being incidental rather than the primary function. A sand filter treats water as it passes through media, not by infiltrating it into the ground. So the infiltration trench best exemplifies an infiltration practice.