26 Devlins Creek - Lower
Water Quality Ranking: 6 / 43
Data Reliability Ranking:
18 / 43Constituent Council(s):Hornsby Shire Council
Constituent stream(s):Devlins Creek and tributaries
Rainfall Station(s):R14
Sewerage Overflows: 9
Stormwater outlets: 2
Water Quality sampling points: WQ011, WQ020, WQ054, WQ055, WQ056
Pollution Control Device Numbers: D024
Overview:
Landuse:
|
Landuse |
Area (ha) |
% sub-catchment |
% LCR catchment |
|
Open space |
140 |
36 |
7.1 |
|
Residential |
241 |
62 |
5.1 |
|
Business |
3 |
1 |
2.3 |
|
Industrial |
0 |
0 |
0 |
|
Special Uses |
6 |
2 |
0.7 |
|
Special Zones |
0 |
0 |
0 |
|
Total |
390 |
100 |
4.8 |
Period of sampling records: August 1989 - August 1998 % wet days: 15
Number of sampling occasions (N):63
Compliance of key indicators to guidelines - % of time guidelines met under all conditions.
|
Parameter |
|||||||
|
pH |
Faecal Coliforms |
% Diss. Oxygen |
Diss. Solids |
Total P |
Total N |
Ammonia |
Chl. - A |
|
97 |
27 |
21 |
82 |
79 |
58 |
27 |
no test |
Summary: Water quality in this sub-catchment is fair but faecal coliform levels indicate that some leakage from sewer is occurring. The creeks have low DO levels indicating possible low flow and stagnation. Nutrient levels however seen to be lower than elsewhere in the catchment.
Issues: This sub-catchment has a high proportion of bushland both for itself and the whole catchment. This area is important in maintaining water quality for the remainder of Devlins creek since it forms part of the headwaters.
Knowledge Gaps: Information regarding sewerage and water quality monitoring is adequate (an expansion of the tests used would be useful) but more information on the location of stormwater outlets is required.
Recommendations: Careful attention should be paid to control nutrient levels reaching the waterways. The condition of the sewerage system should also be carefully monitored to ensure that degradation is caught early.