Laserfiche WebLink
t 2-05- t 997 a : 18PF1 FROG-t ENG- wEST ELK ~-t I NE 970 9295050 p S <br />Febrr~my !0, 1997 Page 2 <br />sumps and to neat the water, if necessary. Revisions regarding these plans will be <br />forthcoming to the Division. <br />3. The sampling of the streams within and adjacent to the permit area has been designed to <br />capture the rising limb of the hydrograph (April 3 to May 13), the hydrograph peak (April <br />21 to June 26), and the hydrograph low (July ] 0 to October 8). These time frames were <br />established per a statistical evaluation as presented and approved by the Division in <br />~, Technical Revision No. 54. Sylvester Gulch, Dry Fork, and Lick Creek aze ephemeral or <br />intermittent drainages, which is why full suite samples for all streams (with the exception of <br />the North Fork of the Gunnison River) are collected during the second sampling period. <br />Please recognize that a null resuh such as a no flow reading is as much of a result as Sow <br />and water quality readings when there is flow. MCC will try to collect the required field <br />parameters and flow earlier in the third sampling period, between July 10 and October 8. <br />4. MCC has prepared the AHIts to include compiled and reduced data wllected during the <br />water year in the form of tables and graphs that present the data in a concise manner and <br />identify trends in the water quality or water quantity. Data from laboratory data sheets are <br />included for these presentations. MCC believes that providing the laboratory data sheets <br />would be unnecessary and duplicative. MCC is aware that in the past there have been some <br />errors in transcribing data from the data sheets to the tables, which may have caused some <br />confusion. For this MCC apologizes and will make improvements in the quality review of <br />the AHR document prior to submittal to the Division At no additional information is <br />provided on the laboratory sheets they will not be submitted with future AHRs. <br />5. The chain-0f--custody documents that accompany every shipment of samples to a laboratory <br />typically specify analyses to be completed for each sample shipment listing or by referencing <br />~ parameter lists on file at the laboratory. This is common practice and MCC believes that <br />this information is not necessary to be added to the AHIts. <br />6. As part of MCC's ongoing quality assurance and quality control, MCC may request that the <br />laboratory provide an anion and cation balance 85 a check on the laboratory analytical data. <br />MCC does not believe that a revision to the permit is necessary to accomplish this task <br />In regard to the addition of a North Fork lower station, MCC believes that the only accurate <br />method for determining stream discharge on a stream the size of the North Fork of the <br />Gunnison River is to install a gaging station or a staff gage. Neither option is cost effective <br />or practical. The gaging station would be comparable in accuracy to the data generated by <br />the upstream USGS station. However, according to a i7SGS hydrologist, any changes in <br />flow between the existing upper USGS station and a lower station could not be measured <br />due to the level of accuracy of the gages. In addition, installing such a structure would <br />require extensive permitting and involve a significant capital investment that would not <br />provide accurate and usefirl flow data. <br />The accuracy of the upstream USGS gage is reported to be in the range of +!- 5 to +l-10 <br />percent. The accuracy of a downstream staff gage will be considerably poorer. For <br /> <br />