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<br />1 <br /> <br />1 <br />it <br /> <br />1 <br /> <br />1 <br /> <br />1 <br /> <br />1 <br />1 <br />William J. Carter March 12, 1998 <br />Re: Response to Susan Burgmaier's comments on the 1996 Annual Hydrologic Report <br />Monitoring of the streams would have to be conducted at least weekly, if not daily, to ensure a <br />sample was taken at the first opportunity in the first quarter. <br />The benefits gained from sampling early in each quarter would not increase the Sanbom Creek <br />Mine or the Division of Minerals and Geology's ability to characterize water quality in the <br />ephemeral drainages. A sample from March and a sample from April 1 hardly qualifies as <br />quarterly sampling. It is reasonable to expect a single quarterly sample from an ephemeral drainage <br />that flows only about three months per year. Also, the fact that there was no flow, is data in itself. <br />Comment l.c. <br />"The third quarter full suite was missed at Site T-1 for the same reason noted in Item b., above. <br />This information would have been especially important for this site, since 1996 data constitutes <br />baseline data." <br />Response l.c. <br />This comment is responded to in lb. above. Also, the fact that Thompson Creek was dry when <br />monitored during August, September, and October of 1996 indicates an intermittent stream and not <br />a perennial stream. <br />Comment 2. <br />"Field conductivity values rise significantly between Site S-1 and S-2 for the April and May data <br />(80 umhos/cm to 480 umhos/cm in April, 90 to 800 in May). No mention of these results is made <br />in the report text. How does OCM explain this increase?" <br />Response 2. <br />Monitoring of S-1 is donejust above the mine water discharge at Outfa11011, and monitoring of S- <br />2 isdone about 100 yazds below the mine water discharge at Outfa11011. On April 8, 1996, <br />Outfall 011 had afield-measured conductivity of 3,700 umhos/cm, and on May 6, 1996 Outfall 011 <br />had afield-measured conductivity of 3,800 umhos/cm. It stands to reason that S-2 will have higher <br />conductivity than S-1 due to the mine water discharge at Outfall Ol 1. The effluent discharge limits <br />for Outfa11011 are covered under Colorado Wastewater Discharge Permit System, Permit Number <br />CO-0000132. <br />' The concentration of total dissolved solids in the mine water discharge have been known for years, <br />and any potential impacts to water quality in the North Fork of the Gunnison River downstream <br />' from S-2, where Sanbom Creek flows into the North Fork of the Gunnison River, have been <br />addressed in the "Aquatic Impairment Study of the Sanbom Creek Mine Discharge, Somerset, <br />Colorado" by John C. Emerick, Nevis E. Cook, and Susan M. Hoffineister, January 30, 1995. The <br />' report was submitted to the Colorado Department of Public Health and Environment as part of the <br />requirements for Colorado Wastewater Discharge Permit System, Permit Number CO-0000132. <br />Copies of the report were sent to the U.S. Environmental Protection Agency and the Colorado <br />5 <br />!1 <br /> <br />