For a construction site to qualify for the rainfall erosivity waiver, the cumulative rainfall erosivity over the project duration must be less than five and the site must be stabilized with at least a 70 percent vegetative cover or other permanent, non-erosive cover. The rainfall erosivity must be calculated according to the method in U.S. EPA Fact Sheet 3.1 Construction Rainfall Erosivity Waiver dated March 2012.
If it is determined that a construction activity will take place during a time period where the rainfall erosivity factor is less than five, a written waiver certification must be submitted to Ohio EPA at least 21 days before construction activity is scheduled to begin. If the construction activity will extend beyond the dates specified in the waiver certification, the operator must either:
- recalculate the waiver using the original start date with the new ending date (if the R factor is still less than five, a new waiver certification must be submitted) or
- submit an NOI application form and fee for coverage under the Construction Storm Water general permit at least seven days prior to the end of the waiver period.
For guidance, please see U.S. EPAs Small Construction Activity Waivers page.
The Waiver Certification requires a topographical map. Here are two links which can be used to obtain a topographical map:
If your construction site does qualify for the rainfall erosivity waiver, submit the Low Erosivity Waiver Certification form to Ohio EPA (Do not mail the form to U.S. EPA) at the following address:
Ohio Environmental Protection Agency
Division of Surface Water
P.O. Box 1049
Columbus, Ohio 43216-1049
If you need assistance with applying for a rainfall erosivity waiver, please complete the Customer Support Center (CSC) Ask a Question form to have your questions directed to the appropriate technical staff.