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f <br /> Stormwater Pollution Prevention Plan <br /> 6.2 Stormwater Quality Monitoring <br /> 6.2.1 Turbidity Sampling <br /> Monitoring requirements for the proposed project will include either turbidity or water <br /> transparency sampling to monitor site discharges for water quality compliance with the 2005 <br /> Construction Stormwater General Permit(Appendix B). Sampling will be conducted at all <br /> discharge points at least once per calendar week. <br /> Turbidityor transparency monitoringwill follow the analytical methodologies described in <br /> p Y Yt g <br /> Section S4 of the 2005 Construction Stormwater General Permit (Appendix B). The key <br /> benchmark values that require action are 25 NTU onsite, and no more than a 5 NTU increase at <br /> the point where runoff from the site joins downstream runoff. If the NTU benchmark for <br /> turbidity is exceeded, the following steps will be conducted: <br /> 1. Ensure all BMPs specified in this SWPPP are installed and functioning g as <br /> I 2. intended. <br /> Assess whether additional BMPs should be implemented, and document revisions <br /> to the SWPPP as necessary. <br /> 3. Sample discharge location daily until the analysis results are less than 25 NTU <br /> (turbidity). <br /> If after improvements the turbidity is still greater than 25 NTU but less than 5 NTU over <br /> background, for more than 3 days, additional treatment BMPs will be implemented within 24 <br /> hours of the third consecutive sample that exceeded the benchmark value. Additional treatment <br /> BMPs to be considered will include,but are not limited to, offsite treatment, infiltration, <br /> filtration and chemical treatment. <br /> ' If the 25 NTU benchmark for turbidity(or less than 6 cm transparency) is exceeded at any time, <br /> the following steps will be conducted: <br /> 1. Notify the Depai lment of Ecology by phone within 24 hours of analysis (see <br /> Section 5.0 of this SWPPP for contact information). <br /> 2. Continue daily sampling until the turbidity is less than 25 NTU <br /> 3. Initiate additional treatment BMPs such as off-site treatment, infiltration, filtration <br /> and chemical treatment within 24 hours of the first 25 NTU exceedance. <br /> 4. Implement additional treatment BMPs as soon as possible, but within 7 days of <br /> I 5. the first 25 NTU exceedance. <br /> Describe inspection results and remedial actions taken in the site log book and in <br /> monthly discharge monitoring reports as described in Section 7.0 of this SWPPP. <br /> 6.2.2 pH <br /> Sampling and monitoring for pH will occur during the phase of construction when concrete <br /> pouring will be conducted until fully cured (3 weeks from last pour) and discharges are <br /> documented to be below pH 8.5. Samples will be collected weekly at the sedimentation pond <br /> 1 <br /> I17 <br />