Gosford City Council Historical Water Quality Review & Analysis

INTRODUCTION 1-1
1 INTRODUCTION
1.1 Background
Gosford City Council is the custodian of a significant amount of water quality data, which has been
collected over the past 30 years. The effective management and use of this substantial dataset is an
ongoing concern. Difficulties stem from the lack of integration between past monitoring programs,
inconsistent monitoring locations, and a wide variety of constituents that have been analysed in the
past. These issues meant that the information was retained as individual datasets only with little or no
cross-referencing between them.
This report documents the analysis of Gosford Council’s historical water quality data and formulates
a future monitoring strategy, based on an appreciation of the historic results and Council’s allocated
budget. As part of the study, a system for water quality management has been developed by
customizing common desktop software packages for database management (MS Access),
geographical interrogation (MapInfo) and data analysis and presentation (MS Excel). This system
was subsequently used to integrate and analyse the historical data, and provide an understanding of
water quality processes over the past 30 years.
The water quality management system has also been designed to accept new data, and provide
automated reporting on the data, with comparisons and references to the historical data and trends.
The reporting has been designed to slot easily within Council’s standard State of the Environment
report and give an overall indication of the environmental health of Gosford’s waterways.
The following is a summary of the water quality data now held within the water quality database:
• Water quality data spans from 1974 to June 2002;
• There are about 200 different monitoring sites within Brisbane Water, its tributary creeks and the
coastal lagoons within Gosford LGA;
• Over 60 different water quality parameters have been monitored;
• Over 30,000 individual records are stored on the database.
1.2 Water Quality Data Sources
1.2.1 Past Reports
The following reports contained water quality information that was entered into the database:
• Environmental Study of Brisbane Waters (Cheng, 1994) contains water quality results for the
following parameters; dissolved oxygen, water temperature, salinity, turbidity, pH and
phytoplankton. The samples were collected at seven locations in Brisbane Waters from April
1993 to September 1994.
• Water Quality Monitoring of Brisbane Water and Gosford Lagoons (Cheng, 2001) contains
water quality results for the following parameters; water temperature, dissolved oxygen, salinity,
temperature, secchi transparency, pH, turbidity, total phosphorus, ortho-phosphate, total nitrogen,
total inorganic nitrogen, oxidised nitrogen and ammonia. The samples were collected at seven
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