Gosford City Council Historical Water Quality Review & Analysis

FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-14
4.5 Options for Future Water Quality Monitoring
A range of options for the future water quality / environmental health monitoring of Gosford waters
have been considered. The options have been developed in light of Council’s expected financial
restrictions (i.e. currently in the order of $40,000 per annum and possibly increasing to $50,000 -
$60,000 in the future).
Four different options have been formulated, targeting different aspects of the water environment.
Therefore, the options can be adopted individually or in combination, in order to achieve Council’s
objectives regarding future water quality / environmental health monitoring. The options are
discussed in detail below.
4.5.1 Option 1: Routine Monthly Water Quality Monitoring
This option involves continuing the basic program of monitoring that was being carried out by Cheng
(on behalf of Council) prior to July 2002. It would involve a minimum of 10 sites around the coastal
lagoons and within Brisbane Water, and would be monitored on a regular monthly basis.
In-situ water quality would be measured by hand-held probe at the time of sampling. The probe
would measure pH, dissolved oxygen, salinity, temperature and turbidity. Collected water samples
would be tested for BOD, ammonia, oxidised nitrogen, TKN, total nitrogen, orthophosphate, total
phosphorus, suspended solids, chlorophyll-a and enterococci. In addition, it is suggested that three
sites also be analysed for algal counts and composition. Experimental data from the University of
Newcastle suggests that chlorophyll-a concentrations is a good surrogate for primary productivity (i.e.
algae) within the water column. Therefore, monitoring chlorophyll-a at all sites provide an indication
of primary productivity, while concurrent monitoring of algal counts and composition at three sites
will provide additional data for identifying correlations between chlorophyll-a and primary
production.
The sites would include, as a minimum, Wamberal Lagoon, Terrigal Lagoon, Avoca Lagoon,
Cockrone Lagoon, Woy Woy Creek, Narara Creek, Erina Creek, Kincumber Creek, Cockle Creek,
and Booker Bay. The sites for the additional algae monitoring would likely include two coastal
lagoons (one being Cockrone Lagoon) and one site in Brisbane Water. Further consideration to the
locations of sampling should be given in light of the SQAP monitoring being carried out within
Brisbane Water, and the CCCEN Streamwatch monitoring sites within the catchment.
Although it is not intended to target public health, we consider that monitoring a relatively longlasting
bacteria, such as enterococci, would provide a sound basic indicator for sewage inputs to the
waterway associated with overflows and general urban runoff. An alternative to bacteria is faecal
sterols. These compounds, found in the gut of animals (including humans) are a very good indicator
of faecal contamination, as they do not readily break down in the natural environment. Also,
composition of the sterols allows us to identify the source of the contaminant (eg humans, other
omnivores, herbivores, etc). Another alternative, which is used as part of the South-East Queensland
EHMP (refer Section 4.2.1) is d 15 N (delta 15 nitrogen). This is the difference between the 15 N and
14 N isotopes, with 15 N generally associated with sewage discharges. Unfortunately, delta-N and
faecal sterols assessments are both quite expensive at present, although it is understood that the
University of Newcastle has recently developed techniques for rapid assessment of faecal sterols
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