Constituent Council(s): Hornsby Shire Council

Constituent stream(s):Lane Cove River

Scouts Creek

Rainfall Station(s): R14

Sewerage Overflows: 5

Stormwater outlets: 1

Water Quality sampling points: WQ036, WQ059

Pollution Control Device Numbers: D06, D017, D021

Overview:

Land Use:

Period of sampling records: August 1989 - March 1998 % wet days: unknown

Number of sampling occasions (N):4

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

Summary: Water quality in this sub-catchment is fair, though it is clear that sewer overflows are contaminating the waterways. High nutrient levels are also present and may be derived from a number of fertilised ovals.

Issues: This area is important because it contains the headwaters of Lane Cove River. It is important to monitor this area as a reference to the rest of the catchment. It would appear that Hornsby Shire Council recognises the value of this part of the catchment as demonstrated by the installation of PCDs such as GPTs to collect litter and a proposed mini-wetland to ‘absorb’ excess nutrients.

Knowledge Gaps: Further investigation into the location of stormwater outlets is required. This is the only area of Lane Cove catchment which does not have a rainfall station nearby, however AWT does have an operational rain station in Thornleigh (AWT Ref.567091).

Recommendations: Knowledge gaps need to be filled in order to assess the contribution of urban areas on pollutant loads to the catchment and to assess if stormwater is carrying heavy nutrient loads from residential premises. Obtaining additional rainfall information is desirable but not essential.. Topographical and aspect differences do affect local rainfall but this difference is small over the entire catchment.