2009-08-03_HYDROLOGY - C1980005 (2)

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After evaluation of the WET monitoring data and the permittee's request, the Division decided that (1) chronic testing will continue on a semi-annual basis at outfall WTE, (2) monitoring reduction to annual is appropriate for two outfalls ( WTH, and WTI), (3) no further WET testing is required at outfalls WTA, WTC, WTD, WTF, WTG,and WTB. The permit is amended to include these changes. The semi-annual WET (chronic) monitoring requirement will remain for Outfall 008, since toxicity has been demonstrated. After one year, if there is no demonstrated toxicity, the permittee should submit a request to amend the permit to reduce this monitoring requirment. Since the WET test has been passed at outfalls WTH, and WTI during the past two years, this monitoring frequency can be reduced to annual testing per biomonitoring guidance. Further, the biomonitoring guidance was recently changes to allow reduction from chronic to acute testing where the receiving water exhibits intermittant or zero low flow. Since the receving waters for these two outfalls possess these flow properties, the annnual monitoring is changed to acute testing. WET testing can not be removed since these outfalls receive flow from active mining areas and, thus, are assumed to possess reasonable potential for toxicity. On March 23, I talked to the Division's permit writer, Gary Beers. He stated to me that the public comment period for this revision would end on April 19, 2009, and that the effective date of the revised permit would be May 1, 2009. He further indicated that I need not sample WET in accordance with the old permit, but rather that I may sample WET in this quarter in accordance with the new permit. Seneca submitted a comment letter dated March 31. Seneca requested some minor corrections, but nothing that would substantially change the monitoring frequencies as stated in the new permit. However, due to a delay, the new permit was not amended until May 29, with an effective date of July 1, 2009. I talked to Andrew Nuehart, the Division's permit writer for the final amendment, about this. He indicated that I should reference, in this DMR cover letter, the conversation that I had with Gary Beers on March 23. A chronic WET test was performed on Outfall WTE on samples collected this quarter, and the results are provided in these DMRs. Acute WET tests for Outfalls WTH and WTI were also performed this quarter. However, the DMRs for these two Outfalls in the package are for the chronic WET test. Seneca will submit the results for these acute tests later this year, when we are provided acute WET test DMRs for these Outfalls. Both acute tests passed the effluent limits. Please contact me at 970-276-5209 if you have any questions. Sincerely, w Dennis Jones Hydrologist I 2