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C. Turbidity/Transparency Sampling Requirements <br /> F ; <br /> 1. Sampling Methods <br /> a. If construction activity involves the disturbance of five(5)acres or more,the <br /> Permittee must conduct turbidity sampling per Special Condition S4.C.4.a, below. <br /> b. If construction activity involves one (1) acre or more but fewer than five (5)acres of <br /> soil disturbance,the Permittee must conduct either transparency sampling or <br /> turbidity sampling per Special Condition S4.C.4.a or b, below. <br /> 2. Sampling Frequency <br /> a. The Permittee must sample all discharge points at least once every calendar week <br /> when stormwater(or authorized non-stormwater) discharges from the site or <br /> enters any on-site surface waters of the state (for example, a creek running through <br /> a site); sampling is not required on sites that disturb less than an acre. <br /> b. Samples must be representative of the flow and characteristics of the discharge. <br /> c. Sampling is not required when there is no discharge during a calendar week. <br /> d. Sampling is not required outside of normal working hours or during unsafe <br /> conditions. <br /> e. If the Permittee is unable to sample during a monitoring period, the Permittee must <br /> include a brief explanation in the monthly Discharge Monitoring Report(DMR). <br /> f. Sampling is not required before construction activity begins. <br /> g. The Permittee may reduce the sampling frequency for temporarily stabilized, <br /> inactive sites to once every calendar month. <br /> E <br /> 3. Sampling Locations <br /> a. Sampling is required at all points where stormwater associated with construction <br /> activity(or authorized non-stormwater) is discharged off site, including where it <br /> enters any on-site surface waters of the state (for example, a creek running through <br /> a site). <br /> b. The Permittee may discontinue sampling at discharge points that drain areas of the <br /> project that are fully stabilized to prevent erosion. <br /> c. The Permittee must identify all sampling point(s) in the SWPPP and on the site map <br /> and clearly mark these points in the field with a flag,tape, stake or other visible <br /> marker. <br /> d. Sampling is not required for discharge that is sent directly to sanitary or combined <br /> sewer systems. <br /> e. The Permittee may discontinue sampling at discharge points in areas of the project <br /> where the Permittee no longer has operational control of the construction activity. <br /> Construction Stormwater General Permit Page 13 <br />