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Fresh water River water quality Visual clarity
Visual clarity trends in rivers
Visual clarity trends at the 77 national network sites, 1989–2007
| Site | Trend |
| WH1 | No significant trend |
| WH2 | Meaningful decrease |
| WH3 | Meaningful decrease |
| WH4 | Meaningful decrease |
| AK1 | Meaningful decrease |
| AK2 | No significant trend |
| HM1 | No significant trend |
| HM2 | Meaningful decrease |
| HM3 | No significant trend |
| HM4 | Meaningful increase |
| HM5 | No significant trend |
| HM6 | No significant trend |
| GS1 | No significant trend |
| GS2 | No significant trend |
| GS3 | No significant trend |
| GS4 | Meaningful increase |
| RO1 | No significant trend |
| RO2 | Meaningful increase |
| RO3 | Meaningful decrease |
| RO4 | No significant trend |
| RO5 | No significant trend |
| RO6 | Significant decrease |
| HV1 | Meaningful increase |
| HV2 | No significant trend |
| HV3 | Significant increase |
| HV4 | No significant trend |
| HV5 | Meaningful increase |
| HV6 | No significant trend |
| TU1 | No significant trend |
| TU2 | No significant trend |
| WA1 | No significant trend |
| WA2 | Meaningful increase |
| WA3 | No significant trend |
| WA4 | No significant trend |
| WA5 | Meaningful increase |
| WA6 | No significant trend |
| WA7 | No significant trend |
| WA8 | Meaningful increase |
| WA9 | No significant trend |
| WN1 | Meaningful increase |
| WN2 | Meaningful increase |
| WN3 | No significant trend |
| WN4 | Meaningful increase |
| WN5 | Meaningful increase |
| NN1 | Meaningful increase |
| NN2 | Meaningful increase |
| NN3 | No significant trend |
| NN4 | No significant trend |
| NN5 | Meaningful increase |
| GY1 | No significant trend |
| GY2 | Meaningful increase |
| GY3 | No significant trend |
| GY4 | No significant trend |
| CH1 | No significant trend |
| CH2 | No significant trend |
| CH3 | Meaningful decrease |
| CH4 | Meaningful decrease |
| TK1 | No significant trend |
| TK2 | Meaningful decrease |
| TK3 | No significant trend |
| TK4 | Meaningful increase |
| TK5 | No significant trend |
| TK6 | Meaningful increase |
| AX1 | No significant trend |
| AX2 | No significant trend |
| AX3 | No significant trend |
| AX4 | Meaningful increase |
| DN1 | No significant trend |
| DN2 | No significant trend |
| DN3 | No significant trend |
| DN4 | No significant trend |
| DN5 | Meaningful increase |
| DN6 | Meaningful increase |
| DN7 | Meaningful increase |
| DN8 | Meaningful increase |
| DN9 | Meaningful increase |
| DN10 | Significant increase |
Notes:
(1) A ‘meaningful’ trend is both statistically significant and environmentally meaningful, while a ‘significant’ trend is statistically significant but not necessarily environmentally meaningful (eg, the scale of the change could be very minor).
(2) An increase in visual clarity is seen as an improvement in water quality, while a decrease is seen as a decline in water quality.
Data source: compiled by the Ministry for the Environment using data collected by the National Institute of Water and Atmospheric Research (NIWA).
(1) A ‘meaningful’ trend is both statistically significant and environmentally meaningful, while a ‘significant’ trend is statistically significant but not necessarily environmentally meaningful (eg, the scale of the change could be very minor).
(2) An increase in visual clarity is seen as an improvement in water quality, while a decrease is seen as a decline in water quality.
Data source: compiled by the Ministry for the Environment using data collected by the National Institute of Water and Atmospheric Research (NIWA).
This data comes from the National River Water Quality Network which is operated by NIWA with funding from the Foundation for Research, Science and Technology.
You can access the national network data for 2007, as well as more site information, in this spreadsheet.
You can access the results of trend analysis on the national network data from 1989 to 2007 in this spreadsheet.
Return to nitrogen in rivers page.
Last updated: 10 August 2009
