43 Alexandra Bay
Water Quality Ranking: 43 / 43
Data Reliability Ranking: 33 / 43
Constituent Council(s):Hunters Hill Council
Constituent stream(s):Alexandra Bay
Lane Cove River (estuary)
Rainfall Station(s):R10
Sewerage Overflows: 2
Stormwater outlets: unknown
Water Quality sampling points: WQ001
Pollution Control Device Numbers: none
Overview:
Landuse:
|
Landuse |
Area (ha) |
% sub-catchment |
% LCR catchment |
|
Open space |
4 |
10 |
0.2 |
|
Residential |
33 |
81 |
0.7 |
|
Business |
0.25 |
1 |
0.2 |
|
Industrial |
0 |
0 |
0 |
|
Special Uses |
3.5 |
9 |
0.4 |
|
Special Zones |
0 |
0 |
0 |
|
Total |
41 |
100 |
0.5 |
Period of sampling records: October 1995 to March 1998 % wet days: 26
Number of sampling occasions (N):35
Compliance of key indicators to ANZECC guidelines
|
Parameter |
|||||||
|
pH |
Faecal Coliforms |
% Diss. Oxygen |
Diss. Solids |
Total P |
Total N |
Ammonia |
Chl. - A |
|
no test |
91 |
no test |
|||||
Summary: Water quality in this sub-catchment is generally unknown. Faecal coliforms have been measured by Harbourwatch including a number of wet days and have been found to meet ANZECC guidelines. However, dilution by tidal flushing may result in such compliant value.
Issues: Since much of the sub-catchment is residential, issues of leaking sewer systems and water pollution of waterways are prominent. There is very little open space in this sub-catchment so high nutrient loads are unlikely to be an issue.
Knowledge Gaps: Some sewerage information is known, but no stormwater information. Water quality sampling needs to be undertaken and expanded and a review of the condition of the sewerage system should be undertaken.
Recommendations: Establishment of a routine water quality monitoring programme, and a review of the condition of the sewerage system.