What is the requirement for storm events in relation to the NEL waiver?

The requirement for storm events in relation to the NEL (Non-Exposure Liability) waiver is based on the intensity and duration of rainfall, specifically targeting those events that exceed the 2-year, 24-hour storm threshold. This criterion is essential because such storms are indicative of significant rainfall that has the potential to impact runoff and, consequently, sediment and pollutant discharge from a site.

When a storm event exceeds the 2-year, 24-hour storm, it represents a level of precipitation that can lead to increased erosion and transport of materials from disturbed sites, necessitating careful monitoring and management. Therefore, the focus on these specific storm events aligns with the broader objectives of erosion and sediment control, ensuring that potential environmental impacts are assessed and mitigated effectively.

The other choices do not reflect the regulatory basis for the NEL waiver. Storm events of less than 12 hours may not produce significant runoff to warrant consideration for stormwater regulations, while seasonal restrictions like only summer storms, or temporal limitations such as events happening on weekends, do not align with the necessary hydrological criteria used in stormwater management practices.