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CITY OF EVERETT STORMWATER MANAGEMENT MANUAL
<br /> 2. Place adequately sized drip pans beneath all mounted taps and drip/spill locations during
<br /> filling/unloading of tanks. Valved drain tubing may be needed in mounted drip pans.
<br /> 3. Sweep and clean the tank storage area regularly, if paved.
<br /> 4. Replace or repair tanks that are leaking,corroded,or otherwise deteriorating.
<br /> 5. All installations shall comply with the Uniform Fire Code and the National Electric Code.
<br /> 6. Locate permanent tanks in impervious(Portland cement concrete or equivalent)secondary
<br /> containment surrounded by dikes, or Underwriters Laboratory approved double-walled. The dike
<br /> must be of sufficient height to provide a containment volume of 10 percent of the total enclosed
<br /> tank volume or 110 percent of the volume contained in the largest tank,whichever is greater, or,
<br /> if a single tank, 110 percent of the volume of that tank.
<br /> 7. Slope the secondary containment to drain to a dead-end sump(optional),or equivalent, for the
<br /> collection of small spills.
<br /> 8. Include a tank overfill protection system to minimize the risk of spillage during loading.
<br /> 9. If the tank containment area is uncovered, equip the outlet from the spill-containment sump with
<br /> a shutoff valve,which is normally closed and may be opened, manually or automatically, only to
<br /> convey contaminated stormwater to approved treatment or disposal or convey uncontaminated
<br /> stormwater to a storm drain. Evidence of contamination can include the presence of visible
<br /> sheen,color, or turbidity in the runoff,or existing or historical operational problems at the
<br /> facility. Simple pH measurements with litmus or pH paper can be used for areas subject to acid
<br /> or alkaline contamination.
<br /> 10. At petroleum tank farms, convey stormwater contaminated with floating oil or debris in the
<br /> contained area through an API or coalescent plate type oil/water separator(Volume III, Treatment
<br /> BMPs)or other approved treatment prior to discharge to storm drain or surface water.
<br /> A4.9 Parking and Storage for Vehicles and Equipment
<br /> Description of Pollutant Sources: Parked vehicles at public and commercial parking lots, such as retail
<br /> store,fleet vehicle(including rent-a-car lots and car dealerships),equipment sale and rental parking lots,
<br /> and parking lot driveways, can be sources of toxic hydrocarbons and other organic compounds, oils and
<br /> greases, metals, and suspended solids.
<br /> Required BMPs
<br /> 1. If washing of a parking lot is conducted,the washwater shall be discharged to a sanitary sewer(if
<br /> allowed by the City's Industrial Pretreatment Program at(425)257-8874)or other approved
<br /> wastewater treatment system, or collected for offsite disposal.
<br /> 2. The area shall not be hosed down to a storm drain or receiving water. Parking lots, storage areas,
<br /> and driveways shall be swept regularly to collect dirt,waste, and debris.
<br /> 3. An oil removal system such as an API or coalescing plate oil and water separator,or equivalent
<br /> BMP (see Volume III), approved by the City, is applicable for parking lots meeting the threshold
<br /> vehicle traffic intensity level of a high-use site. For more information on high-use sites,refer to
<br /> Volume I,Chapter 4.3.
<br /> A4.10 Storage of Pesticides, Fertilizers, or Other Products That Can Leach Pollutants
<br /> This activity applies to businesses,public agencies and farms that store non-liquid pesticides,fertilizers,
<br /> or a variety of other products, such as treated lumber,metal building materials,and metal tools,that have
<br /> the potential to leach pollutants into underlying soil or stormwater runoff. The main problem with the
<br /> Volume I V— Source Control
<br /> 3-37
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