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.
Read a description of this figure
(Figure 2a) Percentage of New Zealand monitoring sites at which median concentrations for the specfied time period exceed water quality guidelines for nitrate-nitrogen.
| 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.
