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r <br />Mr. John Weinman <br />November 7, 1997 Page 2 <br />Parameters measured at all sites are: pH, temperature, electroconductivity, and a suite of <br />other parameters listed in two tables in the permit (Table 13-1 for surface water and Table <br />13-2 for ground water). In addition, the discharge volumes are measured at surface sites <br />and the water level is measured at the ground water site. <br />Tables 13-1 and 13-2 of the permit require that most parameter concentrations be reported <br />in milligrams per liter (mg/I) and some in micrograms per liter (µg/l). <br />The report fulfills for 1996 the annual hydrology reporting requirements of Rule <br />4.05.13(4)(c) and the monitoring frequency and parameters specified in the permit. <br />Surface water ggality <br />Water in Dry Creek is poor quality at HGSD 1 before it enters the permit area, and the <br />quality worsens as the water passes through the permit area. The degradation in quality is <br />assumed to not be caused by mining related activities because the creek receives minimal <br />runoff from areas in the permit area where coal leachates could have formed. The stream <br />water's high sodium, sulfate,.and selenium content is consistent with the chemical <br />composition of saline and sodic soils in the Dry Creek drainage in the permit azea. Also, <br />the creek bed may be in hydraulic contact with the Lewis Shale in the permit area. The <br />water in Dry Creek in the permit area is too salty for irrigation, livestock watering, or <br />domestic use. <br />Measured water quality pazameters in 1996 at both of the surface monitoring sites were <br />generally within their historical ranges. <br />Dry Creek flowed at its highest volume in recent years when a flow of 11,717 gpm was <br />measured at HGSD 1 on April 23, 1996. This high flow rate is presumed to have caused <br />the following nine pazameters in the samples taken that day to far exceed historical <br />averages: Mg, Na, conductance, NO3, TDS, TSS, SO„ PO4, and SAR. <br />Fertilizer is assumed to have caused anomalously high NOl and PO, concentrations in <br />samples taken from both of the surface monitoring sites on November 4, 1996. On that <br />same day, a high concentration of Fe (4.44 mg/1) was found in the sample from HGSD 1. <br />The source of the high iron concentration is unknown, but it does not appear to represent <br />a trend. <br />Discharges from the two ponds in the permit area were sampled when the ponds were <br />manually dewa[ered in the spring time. The NPDES Discharge Monitoring Reports <br />indicate that no parae-eter limitations were exceeded at the outfalls. <br />