Have you ever noticed a little dip or “trench” next to the curb? This feature directs the flow of water away from the street or sidewalk and into the gutter. In green infrastructure, a bioswale is a trench that is designed to move water from one place to another, often to a rain garden for infiltration as it sinks into the earth. This activity will introduce bioretention concepts and give students a hands-on opportunity to model a stormwater scenario without a swale to gain an understanding of its benefits.
Environmental and civil engineers consider the topography of a site to identify or create places for water to collect and drain to prevent flooding. Bioswales help to manage large volumes of stormwater by directing water to bioretention areas. Bioretention areas are spaces where soil, plants, and the microbes they support treat stormwater, often forming a small pond before it infiltrates into the soil. In this activity, students will learn basic concepts of bioretention by modeling a swale.
Ask students about places they see water collect and absorb over time. Get them thinking about how these phenomena might causes flooding. For example, a street corner where a drain is the only place the water can go. Discuss the connection between infiltration and permeability, that is, how water can be filtered through bioretention in a permeable space during infiltration.
