3900 BROADWAY BASE FILE 2016-01-01 MF Import

CITY OF EVERETf STORMWATER MANAGEMENf N�ANUAL 1 r 10. The tetrace cross-section should be propottioned to fit the land slope. 'fhe ridge height should include a rcasonable settlement fector. The ridge should ha«a minimum top width af 3 feet at the design height. The minimum crass-sectional azea of thc terrace channel should be 8 square feet for land slopes of 5 percent or less,7 square feet for slopes from 5 to 8 perccnt, and 6 square feet for slopes steeper t6an 8 percent The tercace can be coostcucted wide enough to be maintained using a small cat. Maintenance Standards Maintenance should be performed as needed. Tenaces should be inspected rogulazly; at least once a year, and aftcr large stortr events. 3.2.16 BMP C140: Dust Controf Purpose Dust control prevcnts wind transport of dust from disturbed soil surfaces onto roadways,drainage ways, and surface waters. Condifions of Use ' For use in azeas(including roadways)subject to surface and air movement of dust where onsite end offsite impacts to roadways,drainage ways,or surfacc watcrs are likely. Deslgn and Insta//ation SpeciBcafions 1. Vegetate or mulch azeas that will not receive vehicle traffic. In areas where planting,mulching, ar paving is impractical, apply gravel or landscaping rock. �) 2. Limit dust generation by clearing only those ereas where immediate activity will take place, � leaving the remaining area(s)in the original condition,if stable. Maintain the original ground cover as long as practical. 3. Construct natural or arlificial windbreaks or windscreens. These may be designed as enclosures for small dust sources. 4. Sprinkle the site with water until surface is wet. Repeat as needed. To prevent cartyout of mud onto strect,refer to Stabilized Conswction Enhance(BMP CI05). 5. Irrigation watcr can be used for dust contral. irrigation systems should be installed as a first step 0o sites whero dust control is a concem. 6. Spray exposed soil areas with a dust palliative, following the manufacturer's inshuctions and cautions nguding handling and application. Oil based products are prohibitcd from usc as a dust suppressant. The City may approve other dust palliatives such as calcium chloridc or PAM. 7. PAM(BMP C 126)added ta water at a rate of 0.5 pounds per 1,000 gallons of water per acte and appiied from a water hvck is more effective than water alone. This is due to the increased in6ltration of water into the soil and reduced cvaporation. In addition,small soil particles azc bonded togethcr and are not as easily transported by wind. Adding PAM may actually reduce the quantity oC water decded for dust convol. PAM has also shown to be rclatively afforda6le and thus an extremely wst•effective dust conhol method. 'fechniques that cao be used for unpaved roads end lots include: l. Lower speed limits. High vehicle speed increases the amount of dust stirted up Crom unpaved roads and lots. Vol�me ll—Construction Stormwafer Pollution Prevenfion 3•28