Constituent Council(s):Ku-ring-gai Municipal Council

Constituent stream(s):Lofberg Quarry Creek

Rainfall Station(s):R07

Sewerage Overflows: 1

Stormwater outlets: 16

Water Quality sampling points: WQ016

Pollution Control Device Numbers: D001, D002

Overview:

Landuse:

Period of sampling records: June 1995 - September 1996 % wet days: 20

Number of sampling occasions (N):30

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

Summary: Water quality in this sub-catchment is poor. Exfiltration (leaking) from private sewers and leaching from the old quarry site may be causes of the high faecal coliform and ammonia levels. No dissolved solids tests have been conducted which are important to asses the sediment load from the old quarry site.

Issues: This sub-catchment is largely residential but contains the old quarry site which has had a long and varied history. The quarry is now parkland and has the creek piped through the park underground. Leachate controls are in place to stop leachate from the land fill contaminating the creek and its condition and effectiveness needs to be assessed.

Knowledge Gaps: There is a scarcity of sewage overflow information. Management provisions and techniques to control leachate from the quarry site are required. Tests for total nitrogen, chlorophyll A and dissolved solids need to be conducted.

Recommendations: Only one designed sewage overflow is identified for the sub-catchment. Other overflows must exist in the sub-catchment to be causing the high faecal coliform count. Investigation of other unspecified pollution sources is required. An assessment of the leachate control system at the Quarry site is also required as this may be the source of pollution.

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