Figure 10.10: Trends in macroinvertebrates (%EPT) in rivers in the national monitoring network, 1989–2005
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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 |
