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C. Erosivity Waiver <br /> Construction site operators may qualify for an erosivity waiver from the CSWGP if the <br /> following conditions are met: <br /> 1. The site will result in the disturbance of fewer than 5 acres and the site is not a <br /> portion of a common plan of development or sale that will disturb 5 acres or <br /> greater. <br /> 2. Calculation of Erosivity "R"Factor and Regional Timeframe: <br /> a. The project's rainfall erosivity factor("R" Factor) must be less than 5 during the <br /> period of construction activity, as calculated (see the CSWGP homepage <br /> http://www.ecy.wa.gov/programs/wq/stormwater/construction/index.html for a <br /> link to the EPA's calculator and step by step instructions on computing the "R" <br /> Factor in the EPA Erosivity Waiver Fact Sheet). The period of construction <br /> activity starts when the land is first disturbed and ends with final stabilization. <br /> In addition: <br /> b. The entire period of construction activity must fall within the following <br /> timeframes: <br /> i. For sites west of the Cascades Crest: June 15 — September 15. <br /> ii. For sites east of the Cascades Crest, excluding the Central Basin: <br /> June 15 —October 15. <br /> iii. For sites east of the Cascades Crest, within the Central Basin: no additional <br /> timeframe restrictions apply. The Central Basin is defined as the portions <br /> of Eastern Washington with mean annual precipitation of less than 12 <br /> inches. For a map of the Central Basin(Average Annual Precipitation <br /> Region 2), refer to http://www.ecy.wa.gov/programs/wq/stormwater/ <br /> construction/resourcesguidance.html. <br /> 3. Construction site operators must submit a complete Erosivity Waiver certification <br /> form at least one week before disturbing the land. Certification must include <br /> statements that the operator will: <br /> a. Comply with applicable local stormwater requirements; and <br /> b. Implement appropriate erosion and sediment control BMPs to prevent violations <br /> of water quality standards. <br /> 4. This waiver is not available for facilities declared significant contributors of <br /> pollutants as defined in Special Condition Si.B.1.b. or for any size construction <br /> activity that could reasonably expect to cause a violation of any water quality <br /> standard as defined in Special Condition S 1.B.1.b.ii. <br /> 5. This waiver does not apply to construction activities which include non <br /> stormwater discharges listed in Special Condition S1.C.3. <br /> Construction Stormwater General Permit <br /> Page 1 1 <br />