Laserfiche WebLink
Site SW-N102 is located on the lower end of a small return ditch that flows into Calamity <br /> Draw approximately one quarter mile downstream of Site SW-N101 . When flowing, water <br /> quality samples have been collected at this site since July of 1986 (see Appendix 7-9). <br /> Table 7-49 presents a statistical summary of all water quality data collected at this <br /> site. Figure 7-30 shows the means of milliequivalent values for the major ions during <br /> both seasons. <br /> The water type at SW-N102 during the two seasons is a calcium sulfate. Figure 7-30 <br /> demonstrates that, even as levels of each major ion increase after the irrigation season <br /> ends, the relative proportions of each ion remains consistent (see Appendix 7-8). The <br /> mean value of pH during irrigation is 7.7, while averaging slightly lower during periods <br /> of no irrigation (7.39). <br /> Mean TDS also increases after the irrigation season ends, averaging 1900 mg/l during this <br /> period in comparison to a mean TDS of 1 ,176 mg/l during the irrigation season. <br /> After the irrigation season has ended, TSS, Fe and Fe all average slightly higher (12.5 <br /> mg/l , .88 mg/l and .39 mg/l , respectively) than during the irrigation season (6.8 mg/l , <br /> .49 mg/l and .08 mg/l , respectively). These higher averages for these constituents at <br /> SW-Nl02 after the irrigation season ends probably reflect the gradual recession of tail <br /> water discharge (hence, higher concentrations) after irrigation ceases. <br /> Surface water Site SW-Nl03 is situated in Calamity Draw about 6 miles downstream of <br /> SW-N101. It is the furthest downstream monitoring site Peabody routinely monitors for <br /> water quality in Calamity Draw. Monitoring for water quality at SW-N103 began in July of <br /> 1986 (see Appendix 7-9). Table 7-50 is a statistical summary of water quality data <br /> collected at this site. Figure 7-31 presents a Schoeller diagram of mean milliequivalent <br /> values for the major ions during both seasons at Site SW-Nl03. <br /> The water type at Site SW-Nl03 for both seasons is a calcium magnesium sulfate (see <br /> Appendix 7-8). This water type is very similar to waters sampled upstream in Calamity <br /> Draw at Site SW-N101 . Figure 7-31 shows an identical trend of increased levels of the <br /> major ions during the non-irrigation season as depicted in Figure 7-29 for Site SW-N101. <br /> Interestingly, if one overlaid each figure, it is evident that, during periods of <br /> irrigation, the major ions at SW-N103 are slightly lower than shown at SW-N101. This <br /> suggests that contributions to flow in Calamity Draw between these sites due to irrigation <br /> tail water provides a dilution effect. <br /> 7-147 Revised 04/11/88 <br />