U:\2021\BM210482_IBo_Waihi_North_Project\Documents\WNP_Freshwater_Report_May_2022\FINAL_Freshwater_Report_FOR DELIVERY_June 2022\FINAL DELIVERED 17 JUNE 2022\WAI-985-000-REP-LC-0007_Rev0_Freshwater_20220621_FINAL.docx and Attribute D for QMCI (five-year median of 4.36); Attribute D is below the National Bottom Line for ecosystems health condition. Table 21: Summary statistics for water quality at selected sites along the Ohinemuri River and relevant water quality guidelines 2013-2018. Data provided courtesy of WRC. Data shows median values, with range in parentheses, followed by the number of samples (n). All units g/m3 except where otherwise stated. Site SH25 Queen’s Head Karangahake Gorge NPSFM Attribute Band (for rivers)^ WRC Water Quality Categories$ Sample period 01/201301/2018 01/2013-01/2018 01/199402/2015 Dissolved Oxygen 10.5 (8.8-11.7), n=61 10.4 (8-13) n=61 10.3 (9.7-10.8) n=6 A=>8.0 NBL=5.0 E=>90% S=80-90% U=<80%* pH (pH units) 7.2 (6.4-7.8), n=61 7.1 (6.7-8.3) n=61 7.2 (7.0-7.8) n=6 E=7-8 S=6.5-7 or 8-9 U=<6.5 or >9 Turbidity (NTU) 1.04 (0.55-41), n=61 1.1 (0.4-16.6) n=61 1.48 (0.74-2.1) n=6 E=<2 S=2-5 U=>5 Ammonia (NH4) 0.023 (0.01-0.049), n=61 0.071 (0.011-0.29) n=61 0.03 (0.015-0.037) n=6 A=<0.03 B=>0.03- <0.24 NBL=0.24 TKN 0.13 (0.06-1.02), n=61 0.25 (0.09-0.79) n=31 0.19 (0.13-0.28) n=6 TON (NNN) 0.45 (0.067-0.97), n=61 0.95 (0.042-1.84) n=61 0.68 (0.182-0.84) n=6 Total Phosphorus 0.011 (0.004-0. 162), n=13 0.01 (0.004-0.076) n=61 0.009 (0.004-0.011) n=6 E=<0.01 S=0.01-0.04 U=>0.04 DRP 0.005 (0.004-0.031), n=61 0.005 (0.004-0.015) n=61 0.0045 (0.004-0.005) n=6 A=<0.006C # Default trigger levels for physical and chemical stressors in New Zealand for slightly to moderately disturbed ecosystems (ANZECC, 2000); $E=Excellent, S=Satisfactory, U=Unsatisfactory. $ For Dissolved oxygen the WRC guidelines are expressed in percent saturation, and the monitoring results as g/L. The conversion of empirical units to percent saturation for dissolved oxygen in water is dependent on the water temperature and elevation at the site. However, median dissolved oxygen levels of >10 g/L would be expected to be >90% saturated and therefore be in the Excellent category. See Appendix 6 for critical values. ^ NPSFM 2020. Attribute Bands A to D; NBL=National Bottom Line. C Attributes requiring action plan.
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