What is the maximum drainage area allowed for a perimeter dike or swale?

The maximum drainage area allowed for a perimeter dike or swale is indeed 2 acres. This limitation is set to ensure effective management of runoff and sediment control. Perimeter dikes or swales are designed to capture and redirect stormwater runoff, helping to prevent erosion and sedimentation during construction or land-disturbing activities.

When the drainage area is limited to 2 acres, it helps ensure that the volume of water handled by the perimeter dike or swale is manageable. This control measure is crucial because larger drainage areas may lead to excessive flows that can overwhelm the structure, potentially leading to failure in controlling sediment and water effectively.

Maintaining a smaller drainage area allows for better performance and reliability of the erosion control practices in place, aligning with best management practices aimed at minimizing environmental impact during land alteration activities.