2020-06-04_PERMIT FILE - C1981008A (2)

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Specific Tuttle Draw water monitoring data is included by reference to Tab 7 (Section 7) in Volume B, pages 7-123 to 7-132, of New Horizon 1 Reclamation Plan. Monitoring of water quality at site SW -N 101 was initiated in July of 1986 for purposes of collecting baseline information for the New Horizon 2 mining area. See Attachment 2.04.7-11 (Peabody Appendix 7-9). For both seasons, the water type at Site SW -N101 was a calcium magnesium sulfate. The mean milliequivalent values for each major ion increased during periods of non -irrigation. Average pH measured at SW -N101 was less during periods of no irrigation (7.64) compared to the mean pH representative of the irrigation season (7.82). However, the pH range was larger (7.23 - 8.05) during the non -irrigation months than when irrigation was occurring (7.44 - 7.98). Average TDS dramatically increased at SW -N101 when irrigation shut down, being almost three times the mean (2,942 mg/1) determined at this site when irrigation occurred (1,026 mg/1). Increases in the major ions occurred after irrigation stops greatly influenced increase in TDS, while the relative proportions (percent milliequivalents) of each ion remained fairly constant. Based on the period of record, TSS, FeT and FeD all averaged greater (71.3 mg/1, 1.79 mg/1 and .48 mg/l, respectively) during the irrigation season than the non -irrigation period (28.3 mg/l, 1.12 mg/1, and .15 mg/1, respectively). The opposite was true for MnT, averaging 1.43 mg/1 when irrigation ceased (mid-October through mid-April) compared to a mean of .40 mg/1 during irrigation. Site SW -N102 was located on the lower end of a small return ditch that flows into Calamity Draw approximately one quarter mile downstream of Site SW -N101. When flowing, water quality samples were collected at this site since July of 1986 (Attachment 2.04.7-11 (Peabody Appendix 7-9)). The water type at SW -N102 during the two seasons was a calcium sulfate. Even as levels of each major ion increased after the irrigation season ended, the relative proportions of each ion remained consistent (Attachment 2.04.7-10 (Peabody Appendix 7-8)). The mean value of pH during irrigation was 7.7, while averaging slightly lower during periods of no irrigation (7.39). Mean TDS also increased after the irrigation season ended, averaging 1900 mg/1 during this period in comparison to a mean TDS of 1,176 mg/1 during the irrigation season. After the irrigation season ended, TSS, FeT and FeD all averaged slightly higher (12.5 mg/1, .88 mg/1 and .39 mg/l, respectively) than during the irrigation season (6.8 mg/l, .49 mg/1 and .08 mg/1, respectively). These higher averages for these constituents at SW -N102 after the irrigation season ended probably reflect the gradual recession of tail water discharge (hence, higher concentrations) after irrigation ceases. Surface water Site SW -N103 was situated in Calamity Draw about .6 miles downstream of SW -N101. It was the furthest downstream monitoring site Peabody routinely monitored for water quality in Calamity Draw. Monitoring for water quality at SW -N103 began in July of 1986 (Attachment 2.04.7-11 (Peabody Appendix 7-9)). The water type at Site SW -N103 for both seasons was a calcium magnesium sulfate (Attachment 2.04.7-10 (Peabody Appendix 7-8)). This water type was very similar to waters sampled upstream in Calamity Draw at Site SW -N101. During periods of irrigation, the major ions at SW -N103 were slightly lower than shown at SW -N101. This suggested that contributions to flow in Calamity Draw between these sites due to Page 2.04.7-21 March 2017 (TR -77)