Which document is NOT required for On-Site SWPPP compliance?

The On-Site SWPPP (Storm Water Pollution Prevention Plan) compliance is a vital component of managing stormwater on construction sites. To ensure effective compliance, certain documentation is essential.

The OS_SWPPP form is not universally required for On-Site SWPPP compliance. While it's useful for organizing information and ensuring that all necessary elements are incorporated into the SWPPP, it does not hold the same regulatory weight as the other documents listed. In fact, the NPDES (National Pollutant Discharge Elimination System) coverage approval letter is crucial as it demonstrates that a project has obtained the necessary authorization for stormwater discharges. Local approvals indicate that construction activities adhere to local regulations and ordinances, which is a critical compliance requirement. The critical area permit addresses specific environmental sensitive areas that may need special attention due to their vulnerability.

Therefore, while the OS_SWPPP form can aid in the development of a robust SWPPP, it is not a mandatory document for compliance, making it the correct answer for this question.