Stormwater treatment wetlands (a.k.a. constructed wetlands) are structural practices that incorporate wetland plants in a shallow pool. As stormwater runoff flows through the wetland, pollutants settle and are broken down by biological process in the plants and soil. Wetlands are among the most effective stormwater practices in terms of pollutant removal, and also offer aesthetic value. Stormwater wetlands are fundamentally different from natural wetland systems. Stormwater wetlands are designed specifically for the purpose of treating stormwater runoff, and typically have less biodiversity than natural wetlands both in terms of plant and animal life.