|
AD SYSTEMS EXPANSION EVERETT, WA
<br /> Element 9:Control Pollutants
<br /> • All pollutants, including waste materials and demolition debris, that occur on-site shall be handled
<br /> and disposed of in a manner that does not cause contamination of stormwater. Woody debris may be
<br /> chopped and spread on site.
<br /> • Cover, containment, and protection from vandalism shall be provided for all chemicals, liquid
<br /> products, petroleum products, and non-inert wastes present on the site (see Chapter 173-304 WAC
<br /> for the definition of inert waste). On-site fueling tanks shall include secondary containment.
<br /> • Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic system
<br /> drain down, solvent and de-greasing cleaning operations, fuel tank drain down and removal, and
<br /> other activities which may result in discharge or spillage of pollutants to the ground or into
<br /> stormwater runoff must be conducted using spill prevention measures, such as drip pans.
<br /> Contaminated surfaces shall be cleaned immediately following any discharge or spill incident.
<br /> Emergency repairs may be performed on-site using temporary plastic placed beneath and, if raining,
<br /> over the vehicle.
<br /> • Wheel wash or tire bath wastewater, shall be discharged to a separate on-site treatment system or to
<br /> the sanitary sewer.
<br /> • Application of agricultural chemicals, including fertilizers and pesticides, shall be conducted in a
<br /> manner and at application rates that will not result in loss of chemical to stormwater runoff.
<br /> Manufacturers' recommendations for application rates and procedures shall be followed.
<br /> • BMPs shall be used to prevent or treat contamination of stormwater runoff by pH modifying sources.
<br /> These sources include, but are not limited to, bulk cement, cement kiln dust, fly ash, new concrete
<br /> washing and curing waters, waste streams generated from concrete grinding and sawing, exposed
<br /> aggregate processes, and concrete pumping and mixer washout waters. Stormwater discharges shall
<br /> not cause or contribute to a violation of the water quality standard for pH in the receiving water.
<br /> • Construction sites with significant concrete work shall adjust the pH of stormwater if necessary to
<br /> prevent violations of water quality standards.
<br /> Element 10:Control De-Watering
<br /> • Foundation, vault, and trench de-watering water, which has similar characteristics to stormwater
<br /> runoff at the site, shall be discharged into a controlled conveyance system prior to discharge to a
<br /> sediment trap or sediment pond. Channels must be stabilized, as specified in Element#8.
<br /> • Clean, non-turbid de-watering water, such as well-point ground water, can be discharged to systems
<br /> tributary to state surface waters, as specified in Element #8, provided the de-watering flow does not
<br /> cause erosion or flooding of receiving waters. These clean waters should not be routed through a
<br /> stormwater sediment pond.
<br /> • Highly turbid or otherwise contaminated dewatering water, such as from construction equipment
<br /> operation, clamshell digging, concrete tremie pour, or work inside a cofferdam, shall be handled
<br /> separately from stormwater.
<br /> • Other disposal options, depending on site constraints, may include: 1) infiltration, 2) transport off-site
<br /> in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute state
<br /> waters, 3) Ecology-approved on-site chemical treatment or other suitable treatment technologies, 4)
<br /> sanitary sewer discharge with local sewer district approval, if there is no other option, or 5) use of a
<br /> sedimentation bag with outfall to a ditch or swale for small volumes of localized dewatering.
<br /> NOVEMBER 20, 2017 STORM WATER DRAINAGE SUMMARY PAGE 13
<br />
|