Gosford City Council Historical Water Quality Review & Analysis

RESULTS OF WATER QUALITY DATA ANALYSIS 3-19
3.3.2 Bacteria
Faecal coliforms, and to a lesser extent Total Coliforms, have been monitored in the Gosford waters
as part of past water quality monitoring programs. Laxton has primarily been responsible for
monitoring of bacteria at Gosford as part of environment monitoring programs. Bacterial results from
Laxton’s 1996 – 1998 monitoring program are presented in Table 3.27. This table shows that the
coastal lagoons and the tributary creeks are most susceptible to bacterial contamination, while sites
within the broader Brisbane Water estuary are least affected by bacteria.
Bacteria is also measured by Council as part of their routine Public Health Monitoring Program.
Bacteria in the vicinity of the oyster leases within Brisbane Water are further monitoring under the
Shellfish Quality Assurance Program (SQAP).
Table 3.27 Faecal Coliform Levels (no. per 100mL) 1996 – 1998 (from Laxton, 1999)
Location Median (50%ile) Mean Maximum
Wamberal Lagoon 22 319 7500
Terrigal Lagoon 114 341 2500
Avoca Lagoon 19 173 2250
Cockrone Lagoon 31 172 2000
Narara Creek 95 669 10000
Erina Creek 132 507 5000
Kincumber Creek 410 2671 20000
Cockle Broadwater 8 112 1000
Koolewong 3 20 355
Woy Woy 6 29 300
Booker Bay 16 43 250
3.3.3 Algae
3.3.3.1 Algal counts
Biological monitoring of Brisbane Water and the coastal lagoons was carried out by Cheng between
August 1999 and June 2002 (Ecoscience Technology, 2002). Algal cell count results for the later half
of this monitoring period (i.e. Oct 2000 – June 2002) are summarised in Table 3.28.
Table 3.28 Algal cell count results 2000 – 2002 (Ecoscience Technology, 2002)
Location Minimum Maximum %age over 1000 cells/ml
Narara Ck 7 475 0
Erina Ck 6 1021 2
Kincumber Ck 6 13634 40
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