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 |
Good
|
The ecological health of this site is usually rated good. Occasionally
riffle habitat is available in spring and has been rated moderate
to good.
Ecological health assessment for May 2005
| Habitat |
Ecological health
|
| Edge |
Good
|
| Riffle |
Habitat not present
|
The indicators that are measured in the Hill River are nutrients
(nitrogen and phosphorus), turbidity and salinity.
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
|
|
|
Moderate
|
|
|
Good
|
Nitrogen and phosphorus levels can become elevated as a result
of fertilisers or animal wastes being washed off farms during
storms. Oxidised nitrogen and soluble phosphorus levels are lower
than usual. Previous results have been classified as moderate.
Classifications for total nitrogen, total phosphorus and turbidity
are consistent with previous results.
The Northern
and Yorke NRM Board are implementing recommendations in the
Broughton River Management Plan (refer to the Department
of Water, land and Biodiversity Conservation) to improve water
quality in the Hill River. These include initiatives such as restricting
stock access, revegetating creek lines, erecting and improving
contour banks and prevent erosion.
Water chemistry classification for April to September 2005
|
Indicator
|
Classification
|
|
|
Moderate
|
|
|
Poor
|
|
|
Moderate
|
|
|
Poor
|
|
|
Moderate
|
Nitrogen and phosphorus levels can become elevated as a result
of fertilisers or animal wastes being washed off farms during
storms or due to effluent outfalls. High turbidity is usually
due to the suspension of fine silt carried in the stream after
erosion of surface soils in the catchment and bank erosion within
the stream. Elevated turbidity can reduce plant photosynthesis
and smother small invertebrates or stable habitat such as rocks,
which some invertebrates need.
The poor nutrient results for the recent samples are consistent
with previous results, although the elevated turbidity results
were unusual. Previously, turbidity was classified as good. This
site was sampled less frequently due to reduced flows.
