The re-issued Construction Stormwater General Permit (CSWGP) has been released and went into effect January 1, 2021! Here are some key clarifications and new permit definitions, as well as conditions that can impact your overall project schedule and cost.
While most of the permit requirements remain the same Section S1 – Permit Coverage clarifies that coverage extends to construction-support or staging areas, including offsite locations. This covers off-site equipment staging yards, material storage areas, borrow areas, and parking areas that will be disturbed and discharge stormwater. These areas must be covered by your SWPPP and monitored and inspected during construction.
Section S1 now includes the guidance on how to qualify for an Erosivity Waiver from CSWGP coverage if certain conditions are met for projects that disturb less than 5 acres or are not part of a larger development project or sale. More information can be found on the Erosivity Waiver tools website: Construction stormwater permit – Washington State Department of Ecology.
Section S2 – Application Requirements, now provides better guidance on how to transfer or modify permit coverage. The Transfer of Coverage form must be signed by the current and new discharger and specify the effective date of transfer for permit responsibility and coverage and liability, including any Administrative Orders associated with the permit. Section S2 still requires that you disclose on the Notice of Intent application if you are aware of contaminated soils and/or groundwater at the project site that could be disturbed during construction. If contaminants are present, Ecology may issue an Administrative Order in companion with the Permit coverage and require additional monitoring for contaminants of concern. This has the potential to extend the project schedule and increase complexity and costs associated with capture, pre-treatment, and testing of stormwater and dewatering water prior to discharge, and soils management and offsite disposal.
Monitoring Requirements, Benchmarks, and Reporting Triggers in the 2021 Permit remain largely unchanged, but the Permit now states that to adjust or neutralize high pH water, special written approval is NOT required to use food grade vinegar, or dry ice or CO2 which were already allowed.
For projects that discharge to a waterbody with a TMDL for turbidity, fine sediment, high pH, or phosphorus, a new TMDL completed after your permit application is received by Ecology would only apply to your project if it were imposed through an Administrative Order by Ecology, or through a modification of permit coverage.
Ecology has added the definition for Upset, which means an exceptional incident when there is unintentional and temporary noncompliance with technology-based permit effluent limits because of factors beyond reasonable control. They clarify that an upset doesn’t include noncompliance caused by operational error, improperly designed or inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.
As your project nears completion, the permit redefines Final Stabilization as the completion of all soil disturbing activities at the site in addition to the previous requirement to establish permanent vegetative cover (or equivalent permanent stabilization measures such as pavement, riprap, gabions, or geotextiles) to prevent erosion. This has implications for wrapping up all final utility installations, landscaping, and other punch list items prior to requesting termination of permit coverage. Section S10 also clarifies that partial terminations of permit coverage are not allowed.
Herrera’s CESCLs, engineers, and scientists provide environmental compliance monitoring services during construction on transportation projects, landfills, mine sites, vertical construction projects, sediment dredging and capping, pipeline infrastructure, throughout the Puget Sound Region and beyond. We take pride in providing responsive, proactive, practical solutions, while effectively communicating to keep your project in compliance and on schedule. Contact us today to see how we can support your project!