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2.1.10 Element 10: Control Dewatering <br /> All dewatering water from open cut excavation, tunneling,foundation work,trench, or <br /> underground vaults shall be discharged into a controlled conveyance system prior to discharge <br /> to a sediment trap or sediment pond. Channels will be stabilized, per Element#8. <br /> Clean, non-turbid dewatering water will not be routed through stormwater sediment ponds, and <br /> will not be discharged to systems tributary to the receiving waters of the State in a manner that <br /> does no cause erosion, flooding, or a violation of State water quality standards in the receiving <br /> water. <br /> Highly turbid dewatering water from soils known or suspected to be contaminated, or from use <br /> of construction equipment, will require additional monitoring and treatment as required for the <br /> specific pollutants based on the receiving waters into which the discharge is occurring. Such <br /> monitoring is the responsibility of the contractor. <br /> Dewatering of soils known to be free of contamination will trigger BMPs to trap sediment and <br /> reduce turbidity. Other BMPs to be used for sediment trapping and turbidity reduction include <br /> the following. <br /> Table 4— Dewatering BMPs <br /> Infiltration <br /> Transport off-site in a vehicle (vacuum truck for legal disposal) <br /> Ecology-approved on-site chemical treatment or other suitable treatment technologies <br /> Sanitary or combined sewer discharge with local sewer district approval (last resort) <br /> ❑ Use of sedimentation bag with discharge to ditch or swale (small volumes of localized <br /> dewaterin <br /> Installation Schedules: Start of project and replaced as needed and as start of wet season. <br /> Inspection and Maintenance plan: Responsible staff to make weekly site walks and inspections <br /> to identify deficiencies in onsite BMPs and anticipate potential problems and remedies. <br /> Responsible Staff: Identified Certified Erosion and Sediment Control Lead in Section 3 of this <br /> SWPPP. <br /> Page � 20 <br />