Summary

In total, 25 sites were assessed in 2008 and 35 sites in 2010. No sites were assessed has having excellent channel stability in either year. In 2008, eight sites had good channel stability, 15 sites had fair channel stability and two sites had poor channel stability. By comparison, in 2010 13 sites were graded as having good channel stability, 14 sites as having fair channel stability and two sites had poor channel stability.

In both years, only two sites were assessed as having high habitat quality, indicating optimal habitat for aquatic biota. These sites were Waipoua River and Waipapa at Forest Ranger in 2008 and Mangahahuru at Main Road and Waipapa at Forest Ranger in 2010.

In 2010, 57% of sites were open to livestock access. Generally, these sites were graded as having only fair channel stability.

In 2010, 43% of sites had channel shading greater than 50% and 57% had channel shading less than 50%. Channel shading is an important physical characteristic for macroinvertebrate abundance, as shading controls in-stream temperature and riparian vegetation provides material for in-stream habitats.

Provisional analysis of data collected over the last five years indicates that the habitat at nine sites has improved, the habitat at ten sites has declined and three sites have remained stable. In addition, stability has increased at 13 sites, declined at three sites and remained stable at four sites.

Ten sites have changed grades, either for stability or habitat quality or both, over this period. Three sites have gone from marginal to sub-optimal habitat quality – Mangahahuru at Main Road, Waitangi at Watea and the Wairua River. One site has gone from sub-optimal to poor habitat quality – the Kaeo River. Two sites have gone from sub-optimal to marginal habitat quality – the Ruakaka River and Punakitere River.

Two sites have gone from fair to good stability – Awanui at Waihue Channel and the Opouteke River. Four sites have gone from poor to fair stability – the Whakapara River, Kaeo River, Waitangi at Watea and Victoria River. One site has gone from fair to poor stability – the Wairua River.

Some of these changes require further investigation to enable an accurate interpretation of these results to be made.