bioswales are typically vegetated, mulched, or xeriscaped. they consist of a swaled drainage course with gently sloped sides (less than 6%). bioswale design is intended to safely maximize the time water spends in the swale, which aids the collection and removal of pollutants, silt and debris. depending on the site topography, the bioswale channel may be straight or meander. check dams are also commonly added along the bioswale to increase stormwater infiltration. a bioswale's make-up can be influenced by many different variables, including climate, rainfall patterns, site size, budget, and vegetation suitability.