CA Adopts New Construction Storm Water General Permit
Kathy McKinney-Tovar, R.E.A. Senior Analyst, Vallejo CA
Dischargers in California whose construction activity projects disturb one or more acres of soil are now are required to obtain coverage under the General Permit for Discharges of Storm Water Associated with Construction Activity (Order 2009-0009-DWQ). Discharges from projects that disturb less than one acre but are part of a larger common plan of development that in total disturbs one or more acres must also be covered under this Construction General Permit. Discharges from construction activities that are under the jurisdiction of the Lahontan Regional Water Quality Control Board are excluded from coverage under this state permit. This new general permit was adopted on September 2, 2009 and replaces the previous construction storm water general permit, Order 99-08-DWQ. Construction activity subject to this permit includes clearing, grading and disturbances to the ground such as stockpiling, or excavation, but does not include regular maintenance activities performed to restore the original line, grade, or capacity of the facility.
To obtain coverage under the new permit, a Notice of Intent, Storm Water Pollution Prevention Plan (SWPPP), and other documents required by the general permit must be submitted electronically to the State Water Resources Control Board (SWRCB) by July 1, 2010. Construction sites covered under Order 99-08-DWQ must obtain coverage at Risk Level 1. Linear Underground/Overhead Utility Projects (LUPs) covered under Order 2003-0007-DWQ must obtain permit coverage as a Type 1 LUP.
This Construction General Permit differs from the previous general permit in the following significant ways:
- Dischargers must assess the risk level of a site based on sediment transport and receiving water risk. The risk level determines which permit compliance requirements must be implemented by the site.
- Numeric action levels (NALs) for pH and turbidity and numeric effluent limitations (NELs) for pH have been added to the permit.
- Effluent monitoring and reporting for pH and turbidity in storm water discharges is now required for certain risk level sites to determine compliance with the NELs and to evaluate whether NALs in the general permit are exceeded.
- Some Risk Level 3 dischargers will be required to monitor receiving waters and conduct bioassays.
- Sites must now comply with several minimum BMPs and other requirements that were previously only offered as guidance by the agency.
- Small construction sites (>1 and <5 acres) with an approved waiver are exempt from the Construction General Permit if self-certification is sent to the SWRCB stating that construction activity will occur only when the rainfall erosivity factor is less than five.
- Dischargers will have the option of monitoring and reporting the soil characteristics at their project location to provide better risk determination and eventually better program evaluation.
- Post-construction storm water performance standards will be required for all sites not covered by a Phase I or Phase II MS4 NPDES permit.
- A Rain Event Action Plan (REAP) must be prepared and implemented by certain risk level sites to protect all exposed portions of the site within 48 hours of a likely precipitation event.
- All construction projects that are enrolled for coverage under the general permit for more than one continuous 3-month period must submit information and annually certify that their site is in compliance.
- Key personnel (SWPPP preparers, inspectors, etc) must have certain certifications or registrations and must be trained to assure that they have an adequate level of knowledge and skills to design and evaluate project specifications for compliance with the permit requirements.
- All linear Underground/Overhead Projects (LUPs) resulting in land disturbances of greater than 1 acre are now covered by this permit. Small LUPs ³1 acre and < 5 acres were previously covered under the Small LUP General Permit (Order 2003-0007-DWQ).
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