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Figure 2. Year-by-year change in percentage of New Zealand monitoring sites exceeding standards or guidelines for human consumption and ecosystem protection specified in the DWSNZ and ANZECC, respectively.

Numbers above X axes show the number of sites at which state and trend statistics could be calculated for the parameter in question for the region of interest.

Figure 2. Year-by-year change in percentage of New Zealand monitoring sites exceeding standards or guidelines

Year n1 DWSNZ 2005 ANZECC 2000
MAV2 = 11.3 mg/L TV3 = 7.2 mg/L
# Sites Exceeding % Sites Exceeding4 # Sites Exceeding % Sites Exceeding4
1995 348 22 6.3 46 13.2
1996 382 21 5.5 48 12.6
1997 465 19 4.1 42 9.0
1998 532 24 4.5 50 9.4
1999 523 26 5.0 64 12.2
2000 544 30 5.5 76 14.0
2001 574 25 4.4 66 11.5
2002 605 34 5.6 71 11.7
2003 621 31 5.0 71 11.4
2004 671 32 4.8 90 13.4
2005 695 29 4.2 87 12.5
2006 726 38 5.2 118 16.3
2007 706 29 4.1 102 14.4
2008 711 55 7.7 134 18.8
1995-2008 920 44 4.8 121 13.2
Change in % Exceedence Over Time5     -   0.4

1 Number of sites where median could be calculated (i.e. there was at least one sample result from that site within the time period of interest).

2 Health-related Maximum Allowable Value specified in DWSNZ 2005.

3 Trigger Value for ecosystem protection (95% level) specified in ANZECC 2000.

4 Percentage of monitoring sites at which median exceeds the water quality standard, relative to the total number of sites for which a median could be calculated for the parameter in question within the time period of interest.

5 Trend tests performed on % sites exceeding guideline values for the individual years 1995 to 2008. A null value (-) indicates that no significant trend was detected at the 95% confidence interval. Numbers are in % sites per year indicate significant trends. Negative numbers indicate a decreasing trend.

(Figure 2b) Percentage of New Zealand monitoring sites at which median concentrations for the specfied time period exceed water quality guidelines for ammoniacal-nitrogen.

Year n1 DWSNZ 2005 ANZECC 2000
GV2 = 1.5 mg/L TV3 = 0.9 mg/L
# Sites Exceeding % Sites Exceeding4 # Sites Exceeding % Sites Exceeding4
1995 215 8 3.7 11 5.1
1996 264 8 3.0 11 4.2
1997 347 12 3.5 19 5.5
1998 440 23 5.2 33 7.5
1999 427 24 5.6 31 7.3
2000 455 21 4.6 27 5.9
2001 481 21 4.4 30 6.2
2002 542 31 5.7 41 7.6
2003 525 24 4.6 35 6.7
2004 595 25 4.2 38 6.4
2005 602 26 4.3 36 6.0
2006 642 21 3.3 35 5.5
2007 629 26 4.1 39 6.2
2008 630 23 3.7 35 5.6
1995-2008 918 35 3.8 49 5.3
Change in % Exceedence Over Time5     -   -

1 Number of sites where median could be calculated (i.e. there was at least one sample result from that site within the time period of interest).

2 Aesthetic Guideline Value specified in DWSNZ 2005.

3 Trigger Value for ecosystem protection (95% level) specified in ANZECC 2000.

4 Percentage of monitoring sites at which median exceeds the water quality standard, relative to the total number of sites for which a median could be calculated for the parameter in question within the time period of interest.

5 Trend tests performed on % sites exceeding guideline values for the individual years 1995 to 2008. A null value (-) indicates that no significant trend was detected at the 95% confidence interval. Numbers are in % sites per year indicate significant trends. Negative numbers indicate a decreasing trend.

(Figure 2c) Percentage of New Zealand monitoring sites at which median concentrations for the specfied time period exceed water quality guidelines for E. coli.

Year n1 DWSNZ 2005 ANZECC 2000
 MAV2 = 1 cfu/100 ml TV3 = 100 cfu/100 ml
# Sites Exceeding % Sites Exceeding4 # Sites Exceeding % Sites Exceeding4
1995 12 3 25.0 0 0.0
1996 17 4 23.5 2 11.8
1997 51 8 15.7 0 0.0
1998 74 12 16.2 3 4.1
1999 277 34 12.3 6 2.2
2000 303 50 16.5 7 2.3
2001 340 57 16.8 7 2.1
2002 352 51 14.5 6 1.7
2003 397 62 15.6 9 2.3
2004 460 71 15.4 5 1.1
2005 473 78 16.5 10 2.1
2006 523 85 16.3 7 1.3
2007 535 112 20.9 28 5.2
2008 530 81 15.3 12 2.3
1995-2008 701 162 23.1 17 2.4
Change in % Exceedence Over Time5     -   -

1 Number of sites where median could be calculated (i.e. there was at least one sample result from that site within the time period of interest).

2 Health-related Maximum Allowable Value specified in DWSNZ 2005.

3 Trigger Value for stock drinking water specified in ANZECC 2000.

4 Percentage of monitoring sites at which median exceeds the water quality standard, relative to the total number of sites for which a median could be calculated for the parameter in question within the time period of interest.

5 Trend tests performed on % sites exceeding guideline values for the individual years 1995 to 2008. A null value (-) indicates that no significant trend was detected at the 95% confidence interval. Numbers are in % sites per year indicate significant trends. Negative numbers indicate a decreasing trend.

(Figure 2d) Percentage of New Zealand monitoring sites at which median concentrations for the specfied time period exceed water quality guidelines for iron.

Year n1 DWSNZ 2005
 GV2 = 0.2 mg/L
# Sites Exceeding % Sites Exceeding3
1995 70 30 42.9
1996 125 35 28.0
1997 170 65 38.2
1998 222 82 36.9
1999 174 66 37.9
2000 168 62 36.9
2001 181 56 30.9
2002 231 81 35.1
2003 487 91 18.7
2004 497 112 22.5
2005 571 105 18.4
2006 570 125 21.9
2007 532 99 18.6
2008 626 119 19.0
1995-2008 802 171 21.3
Change in % Exceedence Over Time4     -1.8

1 Number of sites where median could be calculated (i.e. there was at least one sample result from that site within the time period of interest).

2 Aesthetic Guideline Value specified DWSNZ 2005.

3 Percentage of monitoring sites at which median exceeds the water quality standard, relative to the total number of sites for which a median could be calculated for the parameter in question within the time period of interest.

4 Trend tests performed on % sites exceeding guideline values for the individual years 1995 to 2008. A null value (-) indicates that no significant trend was detected at the 95% confidence interval. Numbers are in % sites per year indicate significant trends. Negative numbers indicate a decreasing trend.

(Figure 2e) Percentage of New Zealand monitoring sites at which median concentrations for the specfied time period exceed water quality guidelines for manganese.

Year n1 DWSNZ 2005 DWSNZ 2005 ANZECC 2000
GV2 = 0.04 mg/L  MAV3 = 0.4 mg/L TV4 = 1.9 mg/L
# Sites Exceeding % Sites Exceeding5 # Sites Exceeding % Sites Exceeding5 # Sites Exceeding % Sites Exceeding5
1995 38 22 57.9 8 21.1 1 2.6
1996 112 46 41.1 16 14.3 6 5.4
1997 171 70 40.9 30 17.5 7 4.1
1998 210 86 41.0 38 18.1 3 1.4
1999 183 73 39.9 27 14.8 2 1.1
2000 174 70 40.2 26 14.9 2 1.1
2001 172 70 40.7 25 14.5 2 1.2
2002 209 84 40.2 36 17.2 6 2.9
2003 458 112 24.5 42 9.2 5 1.1
2004 451 97 21.5 31 6.9 4 0.9
2005 546 124 22.7 40 7.3 6 1.1
2006 667 152 22.8 51 7.6 8 1.2
2007 571 126 22.1 39 6.8 8 1.4
2008 673 149 22.1 48 7.1 10 1.5
1995-2008 784 211 26.9 78 9.9 11 1.4
Change in % Exceedence Over Time6     -2.2   -1.1   -0.1

1 Number of sites where median could be calculated (i.e. there was at least one sample result from that site within the time period of interest).

2 Aesthetic Guideline Value specified in DWSNZ 2005.

3 Health-related Maximum Allowable Value specified in DWSNZ 2005.

4 Trigger Value for ecosystem protection (95% level) specified in ANZECC 2000.

5 Percentage of monitoring sites at which median exceeds the water quality standard, relative to the total number of sites for which a median could be calculated for the parameter in question within the time period of interest.

6 Trend tests performed on % sites exceeding guideline values for the individual years 1995 to 2008. A null value (-) indicates that no significant trend was detected at the 95% confidence interval. Numbers are in % sites per year indicate significant trends. Negative numbers indicate a decreasing trend.