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We further note that the Draft EIR's calculations assume that 75 percent of the fugitive dust will be controlled, presumably using watering. The Draft EIR does not explain how this control efficiency would be achieved. Generally, watering of B-33 unpaved roads achieves no more than 50 percent control. The Draft EIR should be cont. r- revised to explain and support the basis for the assumed 75 percent control efficiency and should further require that this level of control be achieved by listing it as mitigation. r IV.D.2 Wind Erosion The Draft EIR states that the emission factor for wind erosion is 5.25 pounds of PM10 per square meter of stockpile area (uncontrolled) and 1.31 pounds per �. square meter of stockpile area (controlled) ("Ib/m2"). The Draft EIR also states that these emissions are based on a continuously exposed stockpile area of 50 square meters. (Draft EIR, Appx. D, p. 10.)There are several problems here. First, we were unable to reproduce the stated emission factors. Second, no support is provided for the velocities used to the make the wind erosion calculations B-34 and they appear low. Third, a 50 square meter stockpile area seems extraordinarily small for a quarry that will produce in excess of 4.0 million tons per year of material. v. Fourth, the Excel spreadsheets in Exhibit 1 calculated wind erosion emissions assuming that these emission factors are actually in units of grams per square meter and the stockpile has an area of 2500 square meters or 50 meters squared. Fifth, the calculations assume 75 percent control with no discussion of how it will be achieved or any requirement that it actually be achieved. This is an extraordinarily high control efficiency for wind erosion of storage piles if achieved using watering, the only fugitive dust control measure mentioned in the Draft EIR. (See, e.g., Draft EIR, p. 3-15 and AP42, Sec. 13.2.4.4.) We were unable, given the time constraints, to untangle these various messes and determine what the wind erosion emissions should be. ` IV.D.3 Handling and Storage The Draft EIR states that the emission factor for handling and storage L activities is 0.0052 pounds of PM10 per ton of material processed (uncontrolled) and 0.00131b/ton (controlled). Draft EIR, Appx. D, p. 9. There are several problems here. B-35 6. First, we were unable to reproduce the stated emission factors. Our calculations indicate that the emission factors should be 0.00811b/ton uncontrolled Land 0.00201b/ton controlled. Second, no support is provided for the mean wind speed (7.4 mph) and material moisture content(0.7%) used to make the calculations. L 25 L