The State Water Board Adopts Onerous New Rules for Storm Water Discharges From Construction Sites

Author(s): Clark Morrison

Source: CCN Client Alert

9/8/2009

On September 2, 2009, the State Water Resources Control Board (“Water Board”) adopted a new National Pollutant Discharge Elimination System Construction General Permit (the “new Permit”) that radically changes storm water management requirements for any construction or demolition activity that results in a land disturbance equal to or greater than one acre, any construction activity that is part of a larger common plan for development or sale of one or more acres of disturbed land, and construction activity associated with linear utility projects. The new Permit will become effective on July 1, 2010 and will replace Order 99-08-DWQ (the “existing Permit”).

The requirements of the new Permit are significantly different and more stringent than those under the existing Permit. Under the existing Permit that has been in effect for the last 10 years, dischargers who implement Best Management Practices (“BMPs”) to the best of their ability are deemed to be in compliance with the Permit. The new Permit, however, sets quantitative standards that must be achieved, regardless of the BMPs that are implemented. In addition, whereas the existing Permit relies on discharger-developed Storm Water Pollution Prevention Plans (“SWPPPs”) as its primary compliance mechanism, the effect of SWPPPs is much more limited under the new Permit.

Significant changes and additions to the new Permit include:

Risk-based Permitting Approach. The new Permit includes a three-tiered system for discharges (identified as Risk Levels 1, 2, and 3) that is based on the relative risk the project poses to causing water quality impacts. Specific Permit requirements for each risk level are set forth in the new Permit and are more onerous the higher the risk level. Risk levels are established by calculating two factors: (i) the project’s sediment risk and (ii) receiving water risk during periods of soil exposure (i.e., grading and site stabilization). Construction activities that are enrolled under the existing Permit will obtain coverage under the new Permit at Risk Level 1.

Numeric Action Levels and Numeric Effluent Limitations. Under the new Permit, dischargers must meet specific Numeric Action Levels (“NALs”) for pH and turbidity. Exceedance of a NAL does not constitute a permit violation, but does trigger mandatory follow-up such as implementation of additional BMPs and/or corrective action.

In addition, the new Permit would require that Risk Level 3 discharges comply with Numeric Effluent Levels (“NELs”) for turbidity and pH. The turbidity of storm water and non-storm water discharges may not exceed 500 Nephelometric Turbidity Units (“NTU”) and the pH of such discharges must be between 6.0 and 9.0 during any project phase where there is a “high risk of pH discharge.” If an effluent sampling result is outside the range of pH NELs or exceeds the turbidity NEL, the discharger would be in violation of the new Permit. Risk Level 3 dischargers would be required to comply with these NELs unless the storm event causing the discharges is determined after the fact to be equal to or larger than the “Compliance Storm Event,” which is defined as the 5-year, 24-hour storm. The main arguments against NELs are that there is little, if any, scientific foundation for the levels imposed and that the NELs fail to consider baseline conditions.

Post-Construction Standards. The new Permit looks not only at construction-related impacts, but also at the direct effects of the construction activities after construction is complete. Under the new Permit, all dischargers, through the use of non-structural and structural measures, will be required to replicate the pre-project water balance (i.e., the volume of rainfall that ends up as runoff) for the smallest storms up to the 85th percentile storm event (or the smallest storm event that generates runoff, whichever is larger). In addition, for projects that disturb more than two acres, dischargers will need to ensure that post-project time of runoff concentration is equal to or greater than pre-project time of concentration. Finally, all dischargers will be required to implement BMPs to reduce pollutants in storm water discharges that are reasonably foreseeable after all construction phases have been completed. This runoff reduction approach is analogous in principle to Low Impact Development or “LID.”.

Increased Best Management Practice Requirements. Whereas the existing Permit requires BMPs only as elements of the SWPPP or as suggested guidance, the new Permit specifies mandatory, minimum BMPs to prevent storm water pollution and post-construction impacts.

Rain Event Action Plan. The existing Permit requires that during the non-rainy season, dischargers are responsible for ensuring that adequate sediment control materials are available to control sediment discharges in the event of a predicted storm. The new Permit goes farther to require that Risk Level 2 and 3 discharge sites develop and implement a Rain Event Action Plan (“REAP”) designed to protect all exposed portions of the site within 48 hours prior to any likely precipitation event. A REAP, a written document specific for each rain event, will be required whenever there is a 50% or greater chance of receiving precipitation in the project area.

Increased Monitoring and Reporting Requirements. The monitoring requirements included in the new Permit are much broader than those contained in the existing Permit. In addition to visual monitoring of discharges at all sites, the new Permit requires the following:

  • Sampling, analysis, and monitoring requirements for non-visible pollutants at all sites subject to the new Permit;
  • Effluent and receiving water monitoring for pH and turbidity for all Risk Level 3 sites;
  • Receiving water bioassessment sampling before and after project completion for larger Risk Level 3 sites; and
  • Submission of an Annual Report no later than September 1 of each year. Each Annual Report must include storm water monitoring and analysis information.

Certification Requirements for Key Project Personnel. The new Permit requires that key personnel, such as SWPPP preparers and inspectors, have specified training or certification.

Penalties for Violations of Permit Conditions. Under the new Permit, any person in violation of the Permit will be subject to a civil penalty of up to $27,500 per calendar day of such violation, as well as any other sanctions and penalties provided for under the Clean Water Act and the Porter-Cologne Water Quality Control Act.

It goes without saying that the new Permit will be costly for California developers and will significantly raise the risk of enforcement actions and substantial monetary penalties. To avoid such risks, developers must clearly understand and follow the requirements imposed under the new Permit.

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