1985-12-22_HYDROLOGY - M1984049 - Laserfiche WebLink

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The injection operation proceeded on a continuous basis from • September 17th until September 28th. The operation was shut down at 11:00 PM until Z:30 PM September Z4th because of mechanical problems. Flow was interrupted during the early morning hours on September Z6th, 27th and 28th due to freezing of the flow lines. Once injection commenced, water levels in the monitor wells were measured on a daily basis using a continuity probe ("M Scope"). Each well was tested for the presence of dye by lowering a submersible ultraviolet lamp wand down the well casing. The UV wand can detect the presence of fluorescein at concentrations as low as 1 ppm. Water levels are given in Table 3 in the subsequent section on hydrology. A slight rise in water levels was observed in all the monitor wells e>:cept M2C during the injection operation, suggesting that communication was achieved. Referring to Table 1, it is noted that theoretical breakthrough volumes were reached in wells M1B, M2C and M3B. However fluorescence was not observed in these wells. Fluorescence was ultimately observed in M2A and M2B in bailer samples taken on October 15th and 17th. This was confirmed by large volume samples collected with an inert gas continuous sampler on October 18th. When this latter sampling was performed, casing fluid was discarded until the temperature, pH and conductance of the samples reached stable levels, indicating that fresh • formation water was being collected. The samples were filtered at the time of collection and preserved by chilling. Perceptible fluorescence was noted in the samples from M2A, while weal; fluorescence was noted in the sample from M2B. However, the colors were a cool bluish green instead of the distinct lime green normal to fluorescein dye. Because the color discrepancy, the samples were tested by photospectrometric methods which confirmed the presence of fluorescein in the sample from M2A and indicated possible trace amounts in the sample from M2B. The analytical report is attached in the appendix. It is believed that the atypical fluorescent reaction may be due to the large concentration of dissolved zinc in the samples. SITE HYDROLOGY The surface hydrologic regime is dominated by the Animas River. A gaging station is located several miles downstream, below the confiluence with Cunningham Gulch. Records for the 1982-83 water year are attached in the appendix. The maximum flows occur in June and July and were in er.cess of 400 cfs averaged on a monthly basis. During the November-April period average flows are less than 50 cfs. The ma>;imum flow • -9-