What is the primary slope criterion for wet swale design at level one?

The primary slope criterion for wet swale design at level one emphasizes maintaining a slope of less than 2%. This specific slope is important because it allows for slow water movement through the swale, which enhances the opportunity for sedimentation and pollutant removal processes within the swale. A gentle slope minimizes the risk of erosion, provides better water quality treatment, and promotes the establishment of vegetation, which plays a crucial role in swale functionality. Steeper slopes could lead to increased water velocities, reducing the swale's effectiveness at filtering contaminants and managing runoff. Maintaining a slope of less than 2% supports effective stormwater management practices.