2018-10-22_REVISION - M2008078 (12)

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Appendix C Page 61 of 67 Permit No.:COG500000 08:15,08:30,08:45,09:00,09:15,09:30,09:45, 10:00,would be averaged for a single 2 hour average data point 08:30,08:45,09:00,09:15,09:30,09:45, 10:00, 10:15,would be averaged for a single 2 hour average data point 08:45,09:00,09:15,09:30,09:45, 10:00, 10:15, 10:30,would be averaged for a single 2 hour average data point This would continue throughout the course of a calendar day. The highest of these 2 hour averages over a month would be reported on the DMR as the daily maximum temperature. At the end/beginning of a month,the collected data should be used for the month that contains the greatest number of minutes in the 2-hour maximum. Data from 11 pm to 12:59 am,would fall in the previous month. Data collected from 11:01 pm to 1:00 am would fall in the new month. 12. "Discharge"-when used without qualification, means the"discharge of a pollutant."See 5 CCR 1002-61.2(22). 13. "Discharge of a pollutant"-the introduction or addition of a pollutant into state waters.See 25-8-103(3)C.R.S. 14. "Dissolved (D)metals fraction"is defined in the Basic Standards and Methodologies for Surface Water 1002-31,as that portion of a water and suspended sediment sample which passed through a 0.40 or 0.45 UM(micron)membrane filter. Determinations of"dissolved"constituents are made using the filtrate. This may include some very small (colloidal)suspended particles which passed through the membrane filter as well as the amount of substance present in true chemical solution. 15. "Geometric mean"for E. coli bacteria concentrations,the thirty(30)day and seven(7)day averages shall be determined as the geometric mean of all samples collected in a thirty(30)day period and the geometric mean of all samples taken in a seven(7) consecutive day period respectively. The geometric mean may be calculated using two different methods. For the methods shown,a, b,c,d,etc.are individual sample results,and n is the total number of samples. Method 1: (1/n) Geometric Mean=(a*b*c*d*...) "*"-means multiply Method 2: Geometric Mean=antilog( [log(a)+log(b)+log(c)+log(d)+...]/n) Graphical methods,even though they may also employ the use of logarithms, may introduce significant error and may not be used. In calculating the geometric mean,for those individual sample results that are reported by the analytical laboratory to be"less than"a numeric value,a value of 1 should be used in the calculations. If all individual analytical results for the month are reported to be less than numeric values,then report"less than"the largest of those numeric values on the monthly DMR. Otherwise, report the calculated value. For any individual analytical result of"too numerous to count"(TNTC),that analysis shall be considered to be invalid and another sample shall be promptly collected for analysis. If another sample cannot be collected within the same sampling period for which the invalid sample was collected(during the same month if monthly sampling is required,during the same week if weekly sampling is required,etc.),then the following procedures apply: i. A minimum of two samples shall be collected for coliform analysis within the next sampling period. ii. If the sampling frequency is monthly or less frequent: For the period with the invalid sample results,leave the spaces on the corresponding DMR for reporting coliform results empty and attach to the DMR a letter noting that a result of TNTC was obtained for that period,and explain why another sample for that period had not been collected. If the sampling frequency is more frequent than monthly: Eliminate the result of TNTC from any further calculations,and use all the other results obtained within that month for reporting purposes. Attach a letter noting that a result of TNTC was obtained, and list all individual analytical results and corresponding sampling dates for that month.