Wingecarribee and Fitzroy Falls Reservoirs are part of the Shoalhaven
system within the Sydney metropolitan water supply network and are both
shallow, well mixed, polymictic water bodies. After construction in 1973,
land use activities within the catchments changed from low intensity grazing
to more intensive practices such as dairying, particularly on the northern
foreshore of Wingecarribee Reservoir, and vegetable farming around Fitzroy
Falls Reservoir. The change in land use practice raised concerns about the
possible impact on water quality of the reservoirs. This study sought to
differentiate between the influence of catchment effects, inter-reservoir
transfers and seasonality to enable an assessment of long term trends in
water quality to be made.
Data collected on a monthly basis by the Water Board between October
1973 and December 1985 were assessed and representative or 'indicator'
variables for the different influences were selected. Classification of the
phytoplankton to create sample clusters followed by discriminant analysis of
the abiotic data were performed to rank the 'indicator' variables
The classification analyses indicated that time of sampling was more
important than site differences in determining clustering and that both
Wingecarribee and Fitzroy Falls Reservoirs were well mixed and similar. The
influence of chronological changes following the initial filling of the
reservoirs, seasonality and inter-reservoir transfers were detected in the
clustering patterns. Changes attributable to land use activities within the
catchments were not detected. The reduction in concentrations of variables
from high values following the initial filling of the reservoirs was the
main influence regulating clustering between 1974 to 1982 and the influence
of seasonality on clustering was most apparent during 1976 and 1978. The
assessment of the influence of inter-reservoir transfers was restricted
because of limited data.
Seasonal periodicities and ongoing changes in the phytoplankton and
physical and chemical data over the study period were assessed as a means of
interpreting and verifying the analysis results.
| Identifer | oai:union.ndltd.org:ADTP/218946 |
| Date | January 1990 |
| Creators | Furler, Wayne, n/a |
| Publisher | University of Canberra. Applied Science |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | ), Copyright Wayne Furler |
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