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 December 2005
| Habitat |
Ecological health
|
| Edge |
Good
|
| Riffle |
Moderate
|
These ratings are consistent with previous results.
Ecological health assessment for May 2005
| Habitat |
Ecological health
|
| Edge |
Good
|
| Riffle |
Good
|
The indicators that are measured in Rocky River 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
|
|
|
Moderate
|
|
|
Good
|
|
|
Good
|
|
|
Good
|
These classifications are consistent with previous results. The
Rocky River catchment is dominated by native vegetation, so pollution
sources are limited, although it is possible that the amount of
nitrogen can increase by animal wastes entering the river during
storms.
Water chemistry classification for April to September 2005
|
Indicator
|
Classification
|
|
|
Good
|
|
|
Moderate
|
|
|
Good
|
|
|
Good
|
|
|
Good
|
These moderate total nitrogen results are unusual although there
have previously been some elevated results. The amount of nitrogen
can be increased by fertilisers or animal wastes being washed
off farms during storms or due to effluent outfalls. Previously
total nitrogen was classified as good.
