Notes:
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Data is derived from 66 sites of the 77 that make up the national monitoring network.
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Higher %EPT indicates better water quality.
Data source: National Institute of Water and Atmospheric Research.
Text description of figure
| Group | Rivers with lowest %EPT | Rivers with median %EPT | Rivers with highest %EPT |
|---|---|---|---|
| 1989 | 0.511346 | 37.3598 | 82.4518 |
| 1990 | 1.04073 | 40.335 | 91.9269 |
| 1991 | 1.95021 | 50.9064 | 92.3474 |
| 1992 | 0.718243 | 40.0522 | 94.1071 |
| 1993 | 1.96189 | 36.0967 | 92.063 |
| 1994 | 0.081467 | 39.6757 | 92.0277 |
| 1995 | 0.513826 | 29.8137 | 88.4952 |
| 1996 | 5.3328 | 37.7582 | 94.436 |
| 1997 | 0.877538 | 49.0027 | 92.2938 |
| 1998 | 1.53427 | 45.9879 | 94.5467 |
| 1999 | 2.48874 | 29.1083 | 90.0681 |
| 2000 | 2.07295 | 45.8186 | 90.2102 |
| 2001 | 1.91848 | 49.2512 | 95.746 |
| 2002 | 8.73106 | 45.5322 | 90.18 |
| 2003 | 5.48595 | 51.1772 | 95.2783 |
| 2004 | 9.55639 | 57.1429 | 89.9206 |
| 2005 | 2.92907 | 48.5362 | 96.9469 |
Figure 10.10: Trends in macroinvertebrates (%EPT) in rivers in the national monitoring network, 1989–2005
March 2021
© Ministry for the Environment