Constituent Council(s):Hornsby Shire Council, Parramatta City Council

Constituent stream(s):Devlins creek and tributaries

Rainfall Station(s):R14, R03

Sewerage Overflows: 24

Stormwater outlets: 38

Water Quality sampling points: WQ010, WQ022, WQ023, WQ062, WQ068

Pollution Control Device Numbers: none

Overview:

Landuse:

Period of sampling records: October 1994 to August 1998 % wet days: 24

Number of sampling occasions (N):58

Compliance of key indicators to guidelines - % of time guidelines met under all conditions.

Summary: Water quality in this sub-catchment is fair. Monitoring has occurred over quite a long time but faecal coliform levels show that the system is not capable of dealing with wet weather volumes. Nutrient levels are better than lower down in the catchment. Chlorophyll - A measurements show that there is some algal growth occurring.

Issues: This is the largest sub-catchment in Lane Cove catchment and is mostly residential. Despite this water quality is fair. The M2 motorway runs through this catchment and has been monitored by Hornsby Shire Council during its construction. The Hills Motorway Corporation has also conducted some turbidity measurements. Unfortunately the water quality sampling has concentrated on the M2 and not monitored at other points.

Knowledge Gaps: Sewerage, stormwater and water quality data is adequate.

Recommendations: Water quality should be continued with careful attention paid to the levels of nutrients and the condition of the stormwater system. Water quality monitoring should be expanded to include other areas of the sub-catchment.