6101 23RD DR W NORPRO 2025-07-29

I IElement 7: Protect Drain Inlets • All storm drain inlets made operable during construction shall be protected so that I stormwater runoff shall not enter the conveyance system without first being filtered or treated to remove sediment. • All approach roads shall be kept clean. I • Inlets should be inspected weekly at a minimum and daily during storm events. Inlet protection devices should be cleaned or removed and replaced when sediment has filled one-third of the available storage (unless a different standard is specified by the product Imanufacturer). Element 8: Stabilize Channels and Outlets I • All temporary on-site conveyance channels shall be constructed and stabilized to prevent erosion. • Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes and downstream reaches shall be provided at the outlets of all conveyance systems. I Element 9: Control Pollutants • All pollutants, including waste materials and demolition debris, that occur on site shall be handled and disposed of in a manner that does not cause contamination of stormwater. I • Cover, containment, and protection from vandalism shall be provided for all chemicals, liquid products, petroleum products, and non-inert wastes present on the site (see Chapter Ii 73-304 WAC for the definition of inert waste). On-site fueling tanks shall include secondary containment. • Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic I system drain down, solvent and de-greasing cleaning operations, fuel tank drain down and removal,and other activities which may result in discharge or spillage of pollutants to the ground or into stormwater runoff must be conducted using spill prevention measures, such I as drip pans. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Emergency repairs may be performed on-site using temporary plastic placed beneath and, if raining, over the vehicle. I • Wheel wash or tire bath wastewater, shall be discharged to a separate on-site treatment system or to the sanitary sewer, if necessary. • Application of agricultural chemicals, including fertilizers and pesticides, shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers' recommendations for application rates and procedures shall be followed. I • BMPs shall be used to prevent or treat contamination of stormwater runoff by pH modifying sources. These sources include, but are not limited to, bulk cement, cement kiln dust, fly I ash, new concrete washing and curing waters, waste streams generated from concrete grinding and sawing, exposed aggregate processes, and concrete pumping and mixer washout waters. Stormwater discharges shall not cause or contribute to a violation of the I water quality standard for pH in the receiving water. • Construction sites with significant concrete work shall adjust the pH of stormwater if necessary to prevent violations of water quality standards. I6/16/2011 Stormwater Site Plan Page 13 I