Identify a common type of structural BMP.

Retention basins are a common type of structural Best Management Practice (BMP) designed to manage stormwater runoff. They function by capturing and storing rainwater runoff, allowing sediments and pollutants to settle out before the water is released. This process helps to prevent contamination of downstream water bodies and mitigates the impact of flooding by controlling the rate of runoff.

Retention basins are typically designed to hold a specific volume of water, providing both water quality benefits through sedimentation and potential habitat benefits for local wildlife. They are engineered structures, often with features like embankments and outflow control devices, making them integral pieces of a comprehensive stormwater management strategy.

In contrast, vegetative buffer strips, while effective for filtration and slowing down runoff, primarily rely on vegetation rather than structural components. Riprap is a type of erosion control that involves placing rocks along shorelines or drainage areas, which is a passive method rather than an engineered structure. In-line filters are typically used for different purposes in stormwater treatment systems but do not represent the same large-scale, integrated approach as retention basins.