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2.1.10 Element 10: Control Dewatering <br /> Dewatering may be necessary at building foundations, water vaults, and pump stations to <br /> remove any groundwater or surface water during a storm event. Discharge from these <br /> installations should be released into the temporary sediment pond. For deep installations, such <br /> as pump stations, that may expose potentially contaminated soils, groundwater shall be handled <br /> separately from stormwater, removed, and disposed in a manner that does not pollute state <br /> waters. <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 /> dewatering <br /> List and describe BMPs: Transport of any contaminated water to a legal disposal site is <br /> required. <br /> Installation Schedules: <br /> Inspection and Maintenance plan: When any contaminated groundwater is encountered. <br /> Responsible Staff: Contractor <br /> 2.1.11 Element 11: Maintain BMPs <br /> All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained <br /> and repaired as needed to ensure continued performance of their intended function. <br /> Maintenance and repair shall be conducted in accordance with each particular BMP <br /> specification (see Volume 11 of the SWMMWW or Chapter 7 of the SWMMEW). <br /> Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar <br /> week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the <br /> site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to <br /> once every calendar month. <br /> All temporary ESC BMPs shall be removed within 30 days after final site stabilization is <br /> achieved or after the temporary BMPs are no longer needed. <br /> Trapped sediment shall be stabilized on site or removed. Disturbed soil resulting from removal <br /> of either BMPs or vegetation shall be permanently stabilized. <br /> Wage 12 <br />