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Order <br />2009-0009-DWQ amended by 2010-0014-DWQ & 2012-0006-DWQ <br /> 9 <br />Use of an ATS can effectively reduce a site's risk of impacting <br />receiving waters. <br /> <br />51. Dischargers located in a watershed area where a Total Maximum Daily <br />Load (TMDL) has been adopted or approved by the Regional Water <br />Board or U.S. EPA may be required by a separate Regional Water <br />Board action to implement additional BMPs, conduct additional <br />monitoring activities, and/or comply with an applicable waste load <br />allocation and implementation schedule. Such dischargers may also <br />be required to obtain an individual Regional Water Board permit <br />specific to the area. <br /> <br />H. Effluent Standards <br /> <br />52. The State Water Board convened a blue ribbon panel of storm water <br />experts that submitted a report entitled, “The Feasibility of Numeric <br />Effluent Limits Applicable to Discharges of Storm Water Associated <br />with Municipal, Industrial and Construction Activities,” dated <br />June 19, 2006. The panel concluded that numeric limits or action <br />levels are technically feasible to control construction storm water <br />discharges, provided that certain conditions are considered. The panel <br />also concluded that numeric effluent limitations (NELs) are feasible for <br />discharges from construction sites that utilize an ATS. The State <br />Water Board has incorporated the expert panel’s suggestions into this <br />General Permit, which includes numeric action levels (NALs) for pH <br />and turbidity, and special numeric limits for ATS discharges. <br /> <br /> <br />Determining Compliance with Numeric Limitations <br />53. This General Permit sets a pH NAL of 6.5 to 8.5, and a turbidity NAL of <br />250 NTU. The purpose of the NAL and its associated monitoring <br />requirement is to provide operational information regarding the <br />performance of the measures used at the site to minimize the <br />discharge of pollutants and to protect beneficial uses and receiving <br />waters from the adverse effects of construction-related storm water <br />discharges. An exceedance of a NAL does not constitute a violation of <br />this General Permit. <br /> <br />54. This General Permit requires dischargers with NAL exceedances to <br />immediately implement additional BMPs and revise their Storm Water <br />Pollution Prevention Plans (SWPPPs) accordingly to either prevent <br />pollutants and authorized non-storm water discharges from <br />contaminating storm water, or to substantially reduce the pollutants to <br />levels consistently below the NALs. NAL exceedances are reported in <br />the State Water Boards SMARTS system, and the discharger is