Water quality maps and information, Aptil - June
River water temperatures (AMJ)
Autumn river water temperatures were mostly in the range 8-16 oC in the South Island and a little warmer in North Island (up to 20 oC in some lowland rivers of central North Island). As is typical there was a definite trend of decreasing temperature with increasing altitude and a weaker trend of decreasing temperature moving south (increasingly latitude). The temperature anomaly map shows that river temperatures tended to be higher than normal for autumn (by up to 2 oC) over most of both islands, and were particularly warm in Hawkes Bay in the North Island and the north of the South Island.
Visual clarity of rivers (AMJ)
Visual clarity of rivers in New Zealand ranges widely reflecting the diversity of soil and rock types modified by vegetation cover and land use. Furthermore, flows in any one river can vary widely, depending on state-of-flow. Over the autumn, most New Zealand rivers had fairly typical clarity, but some unusually high clarities were observed in Northland and Auckland (although not very high in absolute terms given that these rivers are characteristically turbid) and in the lower Motueka River (northern South Island). The Hutt River (near Wellington) was unusually turbid.