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6.2 SURFACE WATER <br />Peak flows for the surface water sites at Trapper Mine in 2016 were higher than expected for <br />the slightly below average precipitation year. The precipitation in 2016 was 14.95 inches, or slightly <br />below the 39 -year average for the Trapper Project of 16.5 inches. The previous seven years of <br />annual precipitation to 2005 had been below normal precipitation prior to the larger precipitation in <br />2005 through 2011, then the very low precipitation in 2012, the near normal in 2013, the slightly <br />above normal precipitation in 2014 and 2015 and slightly below normal in 2016. No failures or <br />monitoring site problems were encountered during 2016 and no compliance limits were exceeded in <br />2016. <br />Values of total suspended solids (TSS) were generally on the low side of ranges observed in <br />previous years. Total dissolved solids (TDS) were generally in an indirect relationship with flow rate <br />when adequate flow occurred at a site to determine the relationship. The TDS of the surface water <br />from the mine area is similar to the TDS from the non -mined area and, therefore, an increase has not <br />been defined, except for an increase in TDS during low flow conditions at NPDES sites 001 and 011. <br />The TDS, conductivity and major constituents varied over expected ranges with an increase in <br />values as ground -water flow to the stream becomes a larger portion of the total flow. The SAR <br />values measured in 2016 were within the natural ranges for this site. Other chemical constituents <br />analyzed from samples collected from the surface water sites showed little change. The variations <br />and magnitude in iron concentration observed in 2016 were typical of natural values for these sites. <br />The total aluminum concentrations observed in 2016 were similar to concentrations observed in <br />previous years. The remainder of the minor constituents measured in 2016 were low and within <br />natural ranges. Monitoring data indicates that Trapper Mine sediment control structures prevented <br />any significant impacts on the surface water systems downgradient of the mine in 2016. <br />Trapper Mining Company 6-6 <br />2016 Annual Report <br />