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# of Sites / # of Excursions <br />Iron, Total Rec. 5/9 <br />All iron excursions were the result of high suspended solids. There is <br />a temporary modification (expires December 31, 2018) of the iron <br />standard as "current conditions". Therefore, this excursion is not <br />considered to be a standard exceedance. <br />Table 16 in Appendix A shows the CDPHE receiving stream standards for <br />Lower Grassy Creek (Yampa Segment 13j). This new segment came into <br />effect December 31, 2014. Table 17 provides a comparison of those <br />standards to water quality data collected this year from NPDES and <br />stream sites in the Grassy Creek basin. Standards that were exceeded <br />are: <br />Parameter # of Sites / # of Excursions <br />Iron, Total Rec. 1/1 <br />Selenium 1/1 <br />The iron excursion was the result of high suspended solids. One sample <br />from YSG5 exceeded the total recoverable iron standard of 1.0 mg/l with <br />a value of 1.6 mg/1 in June 2015. No excursions occurred at NPDES <br />sites. <br />One sample from Site YSG5 exceeded the chronic selenium standard of 4.6 <br />ug/l with a value of 15.7 ug/l in March 2015. The high selenium values <br />at site YSG5 are in part coming from Scotchman's Gulch, which is in <br />contact with Lewis Shale soils. Lewis Shale soils have contributed to <br />the high selenium values observed in many of the streams in this area. <br />However, there is a temporary modification (expires December 31, 2018) <br />of the selenium standard as "current conditions". Therefore, this <br />excursion is not considered to be a standard exceedance. <br />No sites exceeded the sulfide standard this year. The sulfide values <br />provided in Tables 13, 15 and 17 in Appendix A differ from the values <br />reported in Appendix D. The sulfide data presented in Appendix D are the <br />21 <br />