2010-02-19_REPORT - C1980001 (4)

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3.3.2 Surface Water pH Chart 3 shows pH concentrations for monitoring sites TR-A, TR-B, TR-C and TR-D for the period of record. Values of pH during 2009 were consistent with baseline studies and previous ' monitoring. There is no apparent trend regarding pH although only slight variations occur during the monitoring season. Overall, Trout Creek has remained slightly alkaline throughout the period of record. The lowest pH value in 2009 was recorded at monitoring site TR-D in April with a reading of 7.05 standard units and the high was recorded at monitoring site TR-A in August with a reading of 8.65 standard units. 3.3.3 Surface Water Total Suspended Solids Chart 4 shows total suspended solids (TSS) concentrations for monitoring sites TR-A, TR-B, TR-C and TR-D for the period of record. Since 1989, TSS concentrations have remained relatively constant. The relatively constant TSS values observed over much of the period appear to be the result of two conditions. First, the stream channel, significantly altered during a 1984 flood, has stabilized and the stream banks have reestablished vegetation. Second, the section of the creek between TR-A and TR-B has become an inundated marsh as result of a continuous string of beaver ponds. Additionally, several long stretches of the creek between TR-B and TR- D have also become marshes due to numerous beaver dams. Periodically, this general pattern is interrupted, as occurred in 1991, 1993, 1995, 2003, 2005 and 2006. The "spikes" in TSS levels during these years appear to be related to peak flow conditions along Trout Creek. TSS concentrations during the 2009 sampling season closely resemble the general pattern, decreasing as the season lengthens. The TSS concentrations remained fairly static in 2009 and consistent with previous sampling. The lowest TSS concentration in 2009 was <5 mg/L at numerous monitoring sites during numerous events, the high was recorded at monitoring site TR-D in April with a reading of 11 mg/L. 3.3.4 Surface Water Specific Conductivity Chart 5 shows specific conductivity concentrations for monitoring sites TR-A, TR-B, TR-C and TR-D for the period of record. Specific conductivity from September 1992 through the end of the report period was similar to values obtained prior to October 1990. Data taken between October 1990 and August 1992 are believed to be invalid due to instrument errors. TDS values obtained during these same periods do not reflect the increases; therefore it is believed that the data excursions can be attributed to errors with the instrumentation rather than a reflection of actual field conditions. New field equipment has been used since September 1992 along with laboratory verification. The values shown in past reports from 1992 through 1994 are the laboratory values. Since the field values and laboratory values have been in close agreement since 1994, values provided beginning in 1995 are field values. Specific conductivity has exhibited the same trends in 2009 Page 5 ^"-W WCYNGINEM..