Archived water quality assessments
Ecological health
We collect two samples of macroinvertebrates, one from riffle
(or flowing water) habitat and one from edge (still water) habitat.
The diversity of the macroinvertebrate community is used to describe
ecological health as being in good,
moderate or poor
condition.
Ecological health assessment for November 2005
| Habitat |
Ecological health
|
| Edge |
Good
|
| Riffle |
Habitat not present
|
Both the edge and riffle habitat are usually rated in good condition.
However, a riffle habitat was not present on this occasion due
to a reduction in flow in this part of the river.
Ecological health assessment for May 2005
| Habitat |
Ecological health
|
| Edge |
Good
|
| Riffle |
Moderate
|
Water chemistry
The indicators that are measured in the Tod River at White Flat
are nutrients (nitrogen and phosphorus), turbidity and salinity.
The concentrations of these indicators are used to classify the
water chemistry as being in good,
moderate or poor
condition, according to the needs of aquatic ecosystem protection.
Water chemistry classification for October 2005 to March 2006
|
Indicator
|
Classification
|
|
|
Good
|
|
|
Poor
|
|
|
Good
|
|
|
Poor
|
|
|
Good
|
Total nitrogen and total phosphorus levels were higher than normal
during this sampling period. Previously they have been classified
as good. Nitrogen and phosphorus can be elevated as a result of
fertilisers or animal wastes being washed off farms during storms.
The other classifications are consistent with previous results.
Water chemistry classification for April to September 2005
|
Indicator
|
Classification
|
|
|
Good
|
|
|
Good
|
|
|
Good
|
|
|
Good
|
|
|
Good
|
This page was last modified 13-09-2007
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