1996-02-06_REVISION - M1977493 (14)

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0 Chapter 4-Site-Specific Industrial Storm Water BMPs C What Is It Dust controls for land disturbance and demolition areas are any controls that reduce the potential for particles being carried through air or water. Types of dust control are: • Irrigation-Irrigation is a temporary measure involving a light application of water to moisten the soil surface. The process should be repeated as necessary. • Minimization of Denuded Areas-Minimizing soil exposure reduces the amount of soil available for transport and erosion. Soil exposure can be lessened by temporary or permanent soil stabilization controls, such as seeding, mulching, topsoiling, crushed stone or coarse gravel spreading, or tree planting. Maintaining existing vegetation on a site will also help control dust. • Wind Breaks-Wind breaks are temporary or permanent barriers that reduce airborne particles by slowing wind velocities (slower winds do not suspend particles). Leaving existing trees and large shrubs in place will create effective wind breaks. More temporary types of wind breaks are solid board fences, snow fences, tarp curtains, bales of hay, crate walls, and sediment walls. • Tillage-Deep plowing will roughen the soil surface to bring up to the surface cohesive clods of soil, which in turn rest on top of dusts, protecting them from wind and water erosion. This practice is commonly practiced in and regions where establishing vegetation may take time. • Chemical Soil Treatments (palliatives) -These are temporary controls that are applied to soil • surfaces in the form of spray-on adhesives, such as anionic asphalt emulsion, latex emulsion, resin-water emulsions, or calcium chloride. The palliative is the chemical used. These should be used with caution as they may create pollution if not used correctly. When and Where to Use It Dust controls can be used on any site where dust may be generated and where the dust may cause onsite and offsite damage. Dust controls are especially critical in and areas, where reduced rainfall levels expose soil particles for transport by air and runoff. This control should be used in conjunction with other sedimentation controls such as sediment traps. What to Consider To control dust during land disturbance and at demolition areas, exposure of soil should be limited as.much as possible. When possible, work that causes soil disturbance or involves demolition should be done in phases and should be accompanied by temporary stabilization measures. These precautions will minimize the amount of soil that is disturbed at any one time and, therefore, control dust. Oil should not be used to control dust because of its high potential for polluting storm water discharges. Irrigation will be most effective if site drainage systems are checked to ensure that the right • amount of water is used. Too much water can cause runoff problems. 4-40