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• Highway 40, most of the suspended solids originated below this point. Suspended solids concentrations in <br />Red Wash in April, 1979 increased from a mean of 45 to 9813 milligrams per liter from the highway to <br />station SW1-1 while loads increased from 0.13 to 25.70 tons per day, increases of approximately 20,000 <br />percent in each case. These increases apparently result from the lower vegetative cover, a change in soil <br />properties, and the presence of more unconsolidated material below as opposed to upstream from the <br />highway, thus increasing the amount of erosion. Field investigations indicated that a major portion of this <br />increased erosion originated as channel erosion, which has a large effect on sediment yield because of the <br />proximity of the sediment source to the transport media (see Renfro, 1975). <br />Hydrogen ion activity (pH) of surface water in the lease and adjacent areas, tends to be rather constant, <br />varying normally between 6.6 and 8.5, with no significant difference being noted in the White River above <br />and below the lease area tributaries. The slightly basic waters in the area are likely a result of the relatively <br />high bicarbonate concentrations (American Public Health Association et al, 1975). The basic condition of <br />the water, together with the low acidity (maximum measured at the routine monitoring stations was 30 <br />milligrams per liter as calcium carbonate at SW6-1) and the relatively high alkalinity contents (at least an <br />order of magnitude larger than acidity), indicates that acid drainage problems should not develop as a result <br />of mining in the lease area. <br />Both total and dissolved iron concentrations vary widely over this area, but not significantly between the <br />upper and lower White River stations (SW12-1 and SW11-2, respectively). Total iron, which has varied <br />• naturally over the area from 0.130 to 377 milligrams per liter during the 1979-80 baseline period, tends to be <br />Concentrations of dissolved iron at a given station appear to be much more sporadic than total iron. As a <br />result, no specific patterns can be detected. However, dissolved iron concentrations are normally less than <br />lwo percent of the concurrent total iron concentration. Even so, dissolved iron concentrations in excess of <br />2.0 milligrams per liter have been measured in the White River at both SW12-1 and SW11-2. <br />somewhat directly related to flow rate (i.e., higher concentrations occur during the snowmelt runoff penod). <br />This is as expected, due to the probable association of iron with sediment (Hem, 1970), which tends to <br />increase with flow. Data collected to date indicate that concurrent total iron concentrations are also higher <br />in red Wash than in the White River, probably also the result of higher sediment concentrations in Red <br />Wash and differences in the iron content of the source area soils. It is also significant to note that <br />background total iron concentrations greatly exceeded OSM effluent limitations (maximum of 45 milligrams <br />per liter) on those occasions when suspended solids concentrations also naturally exceeded OSM effluent <br />limitations (maximum of 45 milligrams per titer) by several orders of magnitude. <br />Total manganese concentrations in the area are low (normalcy less than 0.1 milligrams per liter). They also <br />tend to be somewhat directly related to flow, again presumably because of the association with sediment <br />(i.e., maximum total manganese concentrations were found when suspended solids concentrations were <br />also at a maximum). The low manganese concentrations are likely associated with the low acidity of the <br />• area (Hem, 1970). <br />Permit Renewal #3 (Rev. 8/99) II.C-42 <br />