SWM ponds must be designed to safely convey water for what storm event level?

SWM ponds are required to be designed to safely convey water for the 100-year storm event level. This design criterion ensures that the pond can handle significant rainfall events that have a 1% chance of occurring in any given year, thus providing a high level of flood protection. By accommodating this level of storm flow, the design helps prevent overflow issues and minimizes the risk of downstream flooding, infrastructure damage, and erosion.

The use of the 100-year storm as a standard reflects the need for a conservative approach to stormwater management, as it is a widely accepted benchmark for ensuring that structures are resilient to considerable weather occurrences. This standard helps in setting clear expectations for capacity and performance, which is critical in urban planning and environmental protection efforts.

In contrast, lesser storm levels—such as the 10-year, 25-year, or 50-year storms—would not provide adequate protection against more severe events that could lead to serious consequences. Consequently, the design for the 100-year storm is vital for long-term sustainability and safety in stormwater management practices.