36 Porters Creek
Water Quality Ranking: 3 / 43
Data Reliability Ranking: 4 / 43
Constituent Council(s):Ryde City Council
Constituent stream(s):Porters Creek
Rainfall Station(s):R12
Sewerage Overflows: 5
Stormwater outlets: 16
Water Quality sampling points: WQ024, WQ039, WQ040, WQ064, WQ067
Pollution Control Device Numbers: none
Overview:
Landuse:
|
Landuse |
Area (ha) |
% sub-catchment |
% LCR catchment |
|
Open space |
35 |
18 |
1.8 |
|
Residential |
62 |
32 |
1.3 |
|
Business |
1.5 |
1 |
1.2 |
|
Industrial |
40 |
20 |
19.8 |
|
Special Uses |
34 |
17 |
4.0 |
|
Special Zones |
24 |
12 |
11.2 |
|
Total |
197 |
100 |
2.4 |
Period of sampling records: August 1989 - April 1998 % wet days: 67
Number of sampling occasions (N):15
Compliance of key indicators to ANZECC guidelines
|
Parameter |
|||||||
|
pH |
Faecal Coliforms |
% Diss. Oxygen |
Diss. Solids |
Total P |
Total N |
Ammonia |
Chl. - A |
|
83 |
50 |
50 |
82 |
17 |
33 |
0 |
50 |
Summary: Water quality in this sub-catchment is poor despite the water quality index of 3 / 43. The index reported is high because over two thirds of the samples were collected in wet weather. This dilutes the overall concentration of pollutants and makes the impact of such pollutants appear less even though the total quantity of pollutants in wet weather will be greater. Problems of eutrophication from high nutrient levels and re-enforced by high chlorophyll-A levels suggest poor water quality. Sewage pollution is also evident.
Issues: Historically, this sub-catchment has been renowned as a source of poor water quality. This is because it contains the old Porters Creek tip site. The site contains agricultural drains and a pumping station to direct leachate collected from the site to sewer but there has been some criticism of its effectiveness. In recent times this system has been overhauled.
Knowledge Gaps: This sub-catchments high profile has concentrated a lot of attention on its water quality so sewerage, stormwater and water quality information is adequate.
Recommendations: