Gosford City Council Historical Water Quality Review & Analysis
Gosford City Council Historical Water Quality Review & Analysis
Gosford City Council Historical Water Quality Review & Analysis
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong><br />
<strong>Historical</strong> <strong>Water</strong> <strong>Quality</strong><br />
Data <strong>Review</strong> and <strong>Analysis</strong><br />
Prepared For:<br />
Prepared By:<br />
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong><br />
WBM Oceanics Australia<br />
Offices<br />
Brisbane<br />
Denver<br />
Karratha<br />
Melbourne<br />
Morwell<br />
Newcastle<br />
Sydney<br />
Vancouver<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
DOCUMENT CONTROL SHEET<br />
WBM Oceanics Australia<br />
Newcastle Office:<br />
126 Belford Street<br />
BROADMEADOW NSW 2292<br />
Australia<br />
PO Box 266<br />
Broadmeadow NSW 2292<br />
Telephone (02) 4940 8882<br />
Facsimile (02) 4940 8887<br />
www.wbmpl.com.au<br />
ACN 010 830 421<br />
Document:<br />
Title:<br />
Project Manager:<br />
Author:<br />
Client:<br />
Client Contact:<br />
Client Reference:<br />
Synopsis:<br />
R.N0754.002.01.doc<br />
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong> <strong>Historical</strong> <strong>Water</strong><br />
<strong>Quality</strong> Data <strong>Review</strong> and <strong>Analysis</strong><br />
Philip Haines<br />
Philip Haines<br />
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong><br />
Leah Wheatley<br />
This document presents the findings of an<br />
investigation of <strong>Council</strong>'s historical water<br />
quality data. It provides a comparison of<br />
the data with ANZECC guidelines, and<br />
recommends a strategy for continued<br />
water quality monitoring in the future.<br />
REVISION/CHECKING HISTORY<br />
REVISION<br />
NUMBER<br />
REVISION<br />
DESCRIPTION<br />
DATE CHECKED BY ISSUED BY<br />
0<br />
Draft<br />
27/8/03<br />
DJW<br />
PEH<br />
1<br />
Final<br />
3/11/03<br />
DJW<br />
PEH<br />
DISTRIBUTION<br />
DESTINATION<br />
REVISION<br />
0 1 2 3 4 5 6 7 8 9 10<br />
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong><br />
WBM File<br />
WBM Library<br />
2<br />
1<br />
10<br />
1<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
CONTENTS<br />
I<br />
CONTENTS<br />
Contents<br />
List of Figures<br />
List of Tables<br />
i<br />
iii<br />
iv<br />
1 INTRODUCTION 1-1<br />
1.1 Background 1-1<br />
1.2 <strong>Water</strong> <strong>Quality</strong> Data Sources 1-1<br />
1.2.1 Past Reports 1-1<br />
1.2.2 Electronic Information 1-2<br />
1.3 Overview of the ANZECC <strong>Water</strong> <strong>Quality</strong> Guidelines 1-3<br />
1.3.1 Protection of Aquatic Ecosystem 1-3<br />
1.3.2 Biological Indicators 1-5<br />
1.3.3 Physical and Chemical Stressors 1-5<br />
1.3.4 Toxicant in <strong>Water</strong> 1-6<br />
1.3.5 Toxicants in Sediment 1-7<br />
1.3.6 Application 1-7<br />
2 GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL 2-1<br />
2.1 Overview 2-1<br />
2.2 General Philosophy of Data Flow and Database Structure 2-2<br />
2.3 Outputs from GWQ 2-5<br />
2.3.1 <strong>Historical</strong> <strong>Analysis</strong> 2-5<br />
2.3.2 Yearly <strong>Analysis</strong> 2-6<br />
2.3.3 Quarterly <strong>Analysis</strong> 2-7<br />
3 RESULTS OF WATER QUALITY DATA ANALYSIS 3-1<br />
3.1 Contemporary <strong>Water</strong> <strong>Quality</strong> Results 3-1<br />
3.1.1 Physical Parameters 3-2<br />
3.1.1.1 Temperature 3-2<br />
3.1.1.2 pH 3-3<br />
3.1.1.3 Turbidity 3-4<br />
3.1.1.4 Secchi Depth 3-5<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
CONTENTS<br />
II<br />
3.1.1.5 Salinity 3-6<br />
3.1.1.6 Dissolved Oxygen 3-7<br />
3.1.2 Chemical Parameters 3-8<br />
3.1.2.1 Ammonia 3-8<br />
3.1.2.2 Oxidised Nitrogen 3-9<br />
3.1.2.3 Total Nitrogen 3-10<br />
3.1.2.4 Orthophosphate 3-11<br />
3.1.2.5 Total Phosphorus 3-12<br />
3.1.3 Compound <strong>Water</strong> <strong>Quality</strong> Index 3-13<br />
3.2 <strong>Water</strong> <strong>Quality</strong> Datasondes 3-14<br />
3.2.1 Brisbane <strong>Water</strong> (Koolewong) 3-14<br />
3.2.2 Avoca Lagoon 3-16<br />
3.2.3 Cockrone Lagoon 3-17<br />
3.3 <strong>Historical</strong> <strong>Water</strong> <strong>Quality</strong> Results 3-18<br />
3.3.1 Chemical Parameters 3-18<br />
3.3.2 Bacteria 3-19<br />
3.3.3 Algae 3-19<br />
3.3.3.1 Algal counts 3-19<br />
3.3.3.2 Chlorophyll-a 3-20<br />
3.3.4 Metals 3-21<br />
4 FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH<br />
MONITORING 4-1<br />
4.1 Discussion of Previous Monitoring Programs 4-1<br />
4.2 The Notion of ‘Environmental Health’ 4-1<br />
4.2.1 Coastal CRC EHMP 4-1<br />
4.2.1.1 <strong>Water</strong> quality 4-2<br />
4.2.1.2 Seagrass 4-3<br />
4.2.1.3 Sewage 4-3<br />
4.2.1.4 Report cards 4-3<br />
4.3 <strong>Review</strong> of ANZECC Monitoring Guidelines 4-5<br />
4.3.1 Introduction 4-5<br />
4.3.2 Setting Objectives 4-5<br />
4.3.3 Study Design 4-7<br />
4.3.4 Field Sampling Program 4-8<br />
4.3.5 Laboratory <strong>Analysis</strong> 4-9<br />
4.3.6 Data <strong>Analysis</strong> and interpretation 4-10<br />
4.3.7 Reporting 4-11<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
LIST OF FIGURES<br />
III<br />
4.4 Outcomes from Community Workshops 4-12<br />
4.4.1 General Comments 4-12<br />
4.4.2 Possible Sites for Future Monitoring 4-12<br />
4.4.3 Possible Parameters for Future Monitoring 4-13<br />
4.4.4 Possible Frequency of Monitoring 4-13<br />
4.4.5 Possible Ways of Reporting the Data 4-13<br />
4.5 Options for Future <strong>Water</strong> <strong>Quality</strong> Monitoring 4-14<br />
4.5.1 Option 1: Routine Monthly <strong>Water</strong> <strong>Quality</strong> Monitoring 4-14<br />
4.5.2 Option 2: Catchment and Receiving <strong>Water</strong> Monitoring 4-15<br />
4.5.3 Option 3: Quarterly Seagrass Depth Monitoring 4-16<br />
4.5.4 Option 4: Quarterly Benthic Macroinvertebrate Monitoring 4-16<br />
4.5.5 Indicative Costs of Options 4-17<br />
4.5.5.1 Assumptions in Determining Costs 4-18<br />
4.6 Recommended Monitoring Program 4-18<br />
4.6.1 Recommendations for a <strong>Gosford</strong> Environmental Health Indicator 4-23<br />
5 REFERENCES 5-1<br />
APPENDIX A: MHL DATASONDE RESULTS: AVOCA LAGOON A-1<br />
APPENDIX B: MHL DATASONDE RESULTS: COCKRONE LAGOON B-1<br />
APPENDIX C: MHL DATASONDE RESULTS: KOOLEWONG C-1<br />
LIST OF FIGURES<br />
Figure 1.1 Classification of ecosystem type for each category 1-4<br />
Figure 1.2 Types of Physical and Chemical Stressors 1-5<br />
Figure 2.1 <strong>Water</strong> <strong>Quality</strong> Data Management System 2-1<br />
Figure 2.2 Data Flow 2-3<br />
Figure 2.3 Database Structure 2-4<br />
Figure 2.4 MapInfo Database Interface 2-4<br />
Figure 2.5 Sample <strong>Historical</strong> Data Chart 2-5<br />
Figure 2.6 Example of a Yearly <strong>Analysis</strong> Report 2-6<br />
Figure 2.7 Example of a Quarterly <strong>Analysis</strong> Report 2-7<br />
Figure 3.1 Sites for Most Recent (Cheng) <strong>Water</strong> <strong>Quality</strong> Monitoring Program 3-1<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
LIST OF TABLES<br />
IV<br />
Figure 4.1<br />
Figure 4.2<br />
Conceptual model of the current ecosystem health of Moreton Bay and its river<br />
estuaries (Coastal CRC) 4-2<br />
Seagrass depth range measures the distance between the upper tidal limit of<br />
seagrass distribution and the lower light-limited distribution 4-3<br />
Figure 4.3 Example of EHMP Report Card 4-4<br />
Figure 4.4 Spatial Distribution of Ecosystem Health Index values in Moreton Bay 4-4<br />
Figure 4.5 Framework for Setting Objectives (ANZECC/ARMCANZ, 2000) 4-5<br />
Figure 4.6 Framework for Study Design (ANZECC/ARMCANZ, 2000) 4-7<br />
Figure 4.7 Framework for Field Sampling Program (ANZECC/ARMCANZ, 2000) 4-8<br />
Figure 4.8 Framework for Laboratory <strong>Analysis</strong> (ANZECC/ARMCANZ, 2000) 4-9<br />
Figure 4.9 Framework for Data <strong>Analysis</strong> (ANZECC/ARMCANZ, 2000) 4-10<br />
Figure 4.10 General Locations of Future Monitoring Sites 4-21<br />
Figure 4.11 Detailed Locations of Monitoring Sites 4-22<br />
LIST OF TABLES<br />
Table 1.1<br />
Default trigger values for Physical and Chemical Stressors as applicable to<br />
<strong>Gosford</strong> <strong>Water</strong>s 1-6<br />
Table 3.1 Annual Medians for Temperature 3-2<br />
Table 3.2 Quarterly Means for Temperature 3-2<br />
Table 3.3 Annual Medians for pH 3-3<br />
Table 3.4 Quarterly Means for pH 3-3<br />
Table 3.5 Annual Medians for Turbidity 3-4<br />
Table 3.6 Quarterly Means for Turbidity 3-4<br />
Table 3.7 Annual Medians for Secchi Depth 3-5<br />
Table 3.8 Annual Medians for Salinity 3-6<br />
Table 3.9 Quarterly Means for Salinity 3-6<br />
Table 3.10 Annual Medians for Dissolved Oxygen 3-7<br />
Table 3.11 Quarterly Means for Dissolved Oxygen 3-7<br />
Table 3.12 Annual Medians for Ammonia 3-8<br />
Table 3.13 Quarterly Means for Ammonia 3-8<br />
Table 3.14 Annual Medians for Oxidised Nitrogen 3-9<br />
Table 3.15 Quarterly Means for Oxidised Nitrogen 3-9<br />
Table 3.16 Annual Medians for Total Nitrogen 3-10<br />
Table 3.17 Quarterly Means for Total Nitrogen 3-10<br />
Table 3.18 Annual Medians for Orthophosphate 3-11<br />
Table 3.19 Quarterly Means for Orthophosphate 3-11<br />
Table 3.20 Annual Medians for Total Phosphorus 3-12<br />
Table 3.21 Quarterly Means for Total Phosphorus 3-12<br />
Table 3.22 <strong>Gosford</strong> <strong>Water</strong> <strong>Quality</strong> Index Range Definition Matrix 3-13<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
LIST OF TABLES<br />
V<br />
Table 3.23 <strong>Water</strong> <strong>Quality</strong> Index for <strong>Gosford</strong> <strong>Water</strong>s, 1999 - 2002 3-15<br />
Table 3.24 Basic Scorecard Index 3-15<br />
Table 3.25 Scorecard for <strong>Gosford</strong> <strong>Water</strong>s, 1999 - 2002 3-15<br />
Table 3.26 Nutrients in the Coastal Lagoons (1993 – 2002) 3-18<br />
Table 3.27 Faecal Coliform Levels (no. per 100mL) 1996 – 1998 (from Laxton, 1999)3-19<br />
Table 3.28 Algal cell count results 2000 – 2002 (Ecoscience Technology, 2002) 3-19<br />
Table 3.29 Chlorophyll-a results (µg/L) 1996 – 1998 (Laxton, 1999) 3-21<br />
Table 4.1 Indicative Costs for Future Monitoring Options 4-17<br />
Table 4.2 Parameters to be monitored 4-20<br />
Table 4.3<br />
Recommended <strong>Water</strong> <strong>Quality</strong> Scores for different sections of the <strong>Gosford</strong><br />
<strong>Water</strong>ways 4-23<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
INTRODUCTION 1-1<br />
1 INTRODUCTION<br />
1.1 Background<br />
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong> is the custodian of a significant amount of water quality data, which has been<br />
collected over the past 30 years. The effective management and use of this substantial dataset is an<br />
ongoing concern. Difficulties stem from the lack of integration between past monitoring programs,<br />
inconsistent monitoring locations, and a wide variety of constituents that have been analysed in the<br />
past. These issues meant that the information was retained as individual datasets only with little or no<br />
cross-referencing between them.<br />
This report documents the analysis of <strong>Gosford</strong> <strong>Council</strong>’s historical water quality data and formulates<br />
a future monitoring strategy, based on an appreciation of the historic results and <strong>Council</strong>’s allocated<br />
budget. As part of the study, a system for water quality management has been developed by<br />
customizing common desktop software packages for database management (MS Access),<br />
geographical interrogation (MapInfo) and data analysis and presentation (MS Excel). This system<br />
was subsequently used to integrate and analyse the historical data, and provide an understanding of<br />
water quality processes over the past 30 years.<br />
The water quality management system has also been designed to accept new data, and provide<br />
automated reporting on the data, with comparisons and references to the historical data and trends.<br />
The reporting has been designed to slot easily within <strong>Council</strong>’s standard State of the Environment<br />
report and give an overall indication of the environmental health of <strong>Gosford</strong>’s waterways.<br />
The following is a summary of the water quality data now held within the water quality database:<br />
• <strong>Water</strong> quality data spans from 1974 to June 2002;<br />
• There are about 200 different monitoring sites within Brisbane <strong>Water</strong>, its tributary creeks and the<br />
coastal lagoons within <strong>Gosford</strong> LGA;<br />
• Over 60 different water quality parameters have been monitored;<br />
• Over 30,000 individual records are stored on the database.<br />
1.2 <strong>Water</strong> <strong>Quality</strong> Data Sources<br />
1.2.1 Past Reports<br />
The following reports contained water quality information that was entered into the database:<br />
• Environmental Study of Brisbane <strong>Water</strong>s (Cheng, 1994) contains water quality results for the<br />
following parameters; dissolved oxygen, water temperature, salinity, turbidity, pH and<br />
phytoplankton. The samples were collected at seven locations in Brisbane <strong>Water</strong>s from April<br />
1993 to September 1994.<br />
• <strong>Water</strong> <strong>Quality</strong> Monitoring of Brisbane <strong>Water</strong> and <strong>Gosford</strong> Lagoons (Cheng, 2001) contains<br />
water quality results for the following parameters; water temperature, dissolved oxygen, salinity,<br />
temperature, secchi transparency, pH, turbidity, total phosphorus, ortho-phosphate, total nitrogen,<br />
total inorganic nitrogen, oxidised nitrogen and ammonia. The samples were collected at seven<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
INTRODUCTION 1-2<br />
locations in Brisbane <strong>Water</strong>, as well as Wamberal Lagoon, Terrigal Lagoon, Avoca Lagoon and<br />
Cockrone Lagoon. The samples were collected between August 2000 to September 2000<br />
• <strong>Water</strong> quality and biological monitoring of Brisbane <strong>Water</strong> and <strong>Gosford</strong> Lagoon (Ecoscience<br />
Technology, 2002) contains water quality results for the following parameters; dissolved oxygen,<br />
temperature, salinity, turbidity, pH, phosphorus (total phosphorus), nitrogen (total nitrogen, total<br />
inorganic nitrogen, oxidised nitrogen and ammonia) and phytoplankton. The samples were<br />
collected at seven locations around Brisbane <strong>Water</strong>, as well as Cockrone Lagoon, Avoca Lagoon,<br />
Terrigal Lagoon and Wamberal Lagoon. The samples were collected from October 2000 and<br />
June 2002<br />
• Phytoplankton Monitoring of Brisbane <strong>Water</strong> and <strong>Gosford</strong> Lagoons (Ecoscience Technology,<br />
2000b) contains phytoplankton results for the period between August 1999 and January 2000.<br />
Samples were collected at seven locations within Brisbane <strong>Water</strong>, and in Wamberal Lagoon,<br />
Terrigal Lagoon, Avoca Lagoon, and Cockrone Lagoon.<br />
• Phytoplankton Monitoring of Brisbane <strong>Water</strong>s and <strong>Gosford</strong> Lagoons (Ecoscience Technology,<br />
2000), contains phytoplankton results for the period between August 1999 and May 2000.<br />
Samples were collected at seven locations within Brisbane <strong>Water</strong>, and in Wamberal Lagoon,<br />
Terrigal Lagoon, Avoca Lagoon, and Cockrone Lagoon. Note that the above report dealt with<br />
some of this information, therefore the remaining information (January to May 2000) was<br />
extracted from this report.<br />
• <strong>Water</strong> <strong>Quality</strong> Monitoring of Brisbane <strong>Water</strong> and <strong>Gosford</strong> Lagoons (Insearch, 2000), contains<br />
water quality results for the following parameters; temperature, dissolved oxygen, salinity, pH,<br />
total phosphorus, total nitrogen, ortho-phosphate, total inorganic nitrogen, oxidised nitrogen and<br />
ammonia. The samples were collected at seven locations in Brisbane <strong>Water</strong>, as well as<br />
Wamberal Lagoon, Terrigal Lagoon, Avoca Lagoon, and Cockrone Lagoon. The samples were<br />
collected for a period between August 1999 and May 2000.<br />
• <strong>Water</strong> <strong>Quality</strong> of <strong>Gosford</strong> Lagoons, (JH & ES Laxton, 1994) contains water quality results for<br />
the following parameters; water temperature, salinity, pH, dissolved oxygen, ammonia, organic<br />
nitrogen, oxidised nitrogen, total nitrogen, orthophosphate and total phosphorus, turbidity, total<br />
suspended solids, and faecal coliforms. The samples were collected at a number of locations in<br />
Wamberal Lagoon, Terrigal Lagoon, Avoca Lagoon and Cockrone Lagoon. The samples were<br />
collected between September 1993 and October 1994.<br />
• <strong>Gosford</strong> Coastal Lagoons Estuary Processes Study (Webb, McKeown & Associates Pty Ltd,<br />
1994) contains water quality information in an appendix obtained, from a number of sources. In<br />
total water quality sampling was undertaken in 35 locations, in Brisbane <strong>Water</strong>, Avoca Lagoon.<br />
Terrigal Lagoon, Cockrone Lagoon and Wamberal Lagoon. The information was collected from<br />
April 1974 to January 1993.<br />
1.2.2 Electronic Information<br />
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong> provided some water quality data in electronic form. The electronic data<br />
included the following:<br />
• Manly Hydraulics Laboratory undertook water quality sampling at three sites; Cockrone<br />
Lagoon, Avoca Lagoon and Brisbane <strong>Water</strong> (Koolewong). The sampling was continuous and<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
INTRODUCTION 1-3<br />
was collected for the period between January 1996 and June 2002. Monitoring included<br />
conductivity, salinity, pH, temperature, dissolved oxygen and turbidity.<br />
• <strong>Gosford</strong> <strong>Water</strong> <strong>Quality</strong> Study, contains water quality data collected by Laxton. Information was<br />
collected at 13 locations in Brisbane <strong>Water</strong>s, as well as Wamberal Lagoon, Terrigal Lagoon,<br />
Avoca Lagoon and Cockrone Lagoon. Data was collected between February 1996 and June<br />
1999. The water quality parameters include temperature, salinity, pH, dissolved oxygen, specific<br />
gravity, turbidity, ammonia, organic nitrogen, oxidised nitrogen, total nitrogen, orthophosphate,<br />
total phosphorus, inorganic suspended solids, volatile suspended solids, chlorophyll-a, and<br />
faecal coliforms.<br />
• <strong>Gosford</strong> <strong>Water</strong> <strong>Quality</strong> Survey Stage 2 Report – Major Tributary <strong>Water</strong> <strong>Quality</strong> Assessment<br />
information (AWT, 2001) contains water quality sampling at three tributaries Kincumber Creek<br />
(four sites), Narara Creek (six sites) and Erina Creek (seven sites). The water quality parameters<br />
that were collected included conductivity, dissolved oxygen, pH, turbidity, faecal coliforms, total<br />
phosphorus, total nitrogen, and ammonia.<br />
1.3 Overview of the ANZECC <strong>Water</strong> <strong>Quality</strong> Guidelines<br />
<strong>Water</strong> quality guidelines have been prepared for Australian and New Zealand waters by the Australia<br />
and New Zealand Environment Conservation <strong>Council</strong> (ANZECC). The most recent guidelines, as<br />
described below were released in 2000, superseding previous guidelines issued in 1992.<br />
The objective of the water quality guidelines for fresh and marine waters (ANZECC, 2000) is;<br />
‘to provide an authoritative guide for setting water quality objectives required<br />
to sustain current, or likely future, environmental values [uses] for natural<br />
and semi-natural water resources in Australia and New Zealand.’<br />
These guidelines were prepared as part of Australia’s National <strong>Water</strong> <strong>Quality</strong> Management Strategy<br />
(NWQMS) and relate to New Zealand’s National Agenda for Sustainable <strong>Water</strong> Management. The<br />
guidelines provide the government and the community with a method for assessing and managing<br />
ambient water quality in natural and semi-natural water resources. These guidelines are not<br />
mandatory and have no legal status.<br />
The guidelines are specifically based on the philosophy of ecologically sustainable development<br />
(ESD). ESD has been defined by the Australian National Strategy for Ecologically Sustainable<br />
Development as;<br />
‘using, conserving and enhancing the community’s resources so that ecological processes<br />
on which life depends, as maintained and the total quality of life, now and in the future can<br />
be increased. Put more simply, ESD is development which aims to meet the needs of<br />
Australians today while conserving our ecosystem to benefit future generations.’<br />
1.3.1 Protection of Aquatic Ecosystem<br />
The document provides guidance to determine whether the water quality of a water resource is<br />
suitable for a range of different uses, including maintenance of natural aquatic ecosystems. Of<br />
specific interest to the <strong>Gosford</strong> <strong>Water</strong> <strong>Quality</strong> Assessment is the suitability of water quality for<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
INTRODUCTION 1-4<br />
aquatic ecosystems. Aquatic systems include animals, plants and micro-organisms that live in the<br />
water as well as the physical and chemical environment and climatic regime that they interact with.<br />
The physical, chemical and biological components of an ecosystem determines what lives and breeds<br />
within the ecosystem. Aquatic ecosystem have suffered profound changes due to human impact,<br />
therefore the ecological objective of these guidelines is:<br />
‘to maintain and enhance the ‘ecological integrity’ of freshwater and marine<br />
ecosystems, including biological diversity, relative abundance and ecological<br />
processes.’<br />
There are diverse ranges of ecosystem types, which have naturally variable physical and chemical<br />
water quality characteristics. In order to consider these varying ecosystems the guidelines classify the<br />
ecosystem into six categories (Figure 1.1). The classification of the ecosystems is quite broad. The<br />
figure shows that there are different classifications depending on the indicator in question (shown on<br />
the left of Figure 1.1).<br />
Figure 1.1 Classification of ecosystem type for each category<br />
In terms of the level of protection of the ecosystem the guidelines suggest three levels depending on<br />
the ecosystem condition. The three ecosystem levels are recognised as, high conservation/ecological<br />
value systems, slightly to moderately disturbed system, and highly disturbed systems. Site-specific<br />
protection levels can also be determined by considering the type and quantity of contaminant that will<br />
possibly enter the aquatic ecosystem.<br />
Indicators are used to determine the overall health of the aquatic ecosystems. These include,<br />
biological indicators, physical and chemical stressors, toxicants, and sediments. These indicators are<br />
described in the following Sections.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
INTRODUCTION 1-5<br />
1.3.2 Biological Indicators<br />
Biological indicators are algae, macrophytes, macroinvertebrates and fish, which display the effects<br />
of the past and present exposure to contaminants or pressures.<br />
Biological assessment (bioassessment) is used to provide information on biological or ecological<br />
changes, which may be due to changes in water quality or physical habitats. Bioassessment and<br />
biological indicators are used because traditional physical and chemical guidelines can be too simple<br />
to provide a meaningful assessment of biological communities or processes. Bioassessment is also a<br />
useful tool to assess achievements of environmental values and attain water quality objectives.<br />
The ANZECC guidelines recommend stressors and biological indicators to be used for monitoring<br />
and assessment of water quality, for different ecosystem types. The indicators are selected depending<br />
on the object of the assessment i.e. broad scale assessment, early detection, or biodiversity or<br />
ecosystem-level response. The guidelines provide concepts and monitoring frameworks that are<br />
necessary to assess aquatic biological communities.<br />
1.3.3 Physical and Chemical Stressors<br />
Physical and chemical stressors include nutrients, biodegradable organic matter, dissolved oxygen,<br />
turbidity, suspended particulate matter (SPM), temperature, salinity, pH, change in flow regime,<br />
ammonia, cyanide, heavy metals, biocides and other toxic organic compounds. Physical and<br />
chemical stressors are classified into two types, depending on whether they have a direct or indirect<br />
impact on the ecosystem, as shown in Figure 1.2.<br />
Figure 1.2 Types of Physical and Chemical Stressors<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
INTRODUCTION 1-6<br />
Default trigger values were derived for the physical and chemical stressors using regional reference<br />
data for climatic/geographical regions across Australia and New Zealand. New Zealand and<br />
Australian state and territory representatives used percentile distributions of available data and<br />
professional judgement to derive trigger values for each of the ecosystems. Trigger values were then<br />
collated, discussed and agreed upon for each region. It is emphasised that these default trigger values<br />
should only be used until site-specific or ecosystem-specific values can be generated. Default trigger<br />
values for South-east Australia estuarine ecosystems are presented in Table 1.1.<br />
Table 1.1<br />
Default trigger values for Physical and Chemical Stressors as applicable<br />
to <strong>Gosford</strong> <strong>Water</strong>s<br />
Physical and Chemical Stressors<br />
Chlorophyll-a<br />
Total Phosphorus<br />
Filterable Reactive Phosphorus (Orthophosphate)<br />
Total Nitrogen<br />
Oxidised Nitrogen<br />
Ammonium<br />
Dissolved Oxygen<br />
pH<br />
Turbidity<br />
Trigger Values<br />
4 µg/L<br />
30 µg P/L<br />
5 µg/L<br />
300 µg N/L<br />
15 µg N/L<br />
15 µg N/L<br />
80% (lower limit) & 110% (upper limit);<br />
7.0 (lower limit) & 8.5 (upper limit);<br />
0.5 – 10 NTU<br />
Physical and chemical trigger values are to be used, in conjunction with professional judgement, to<br />
provide an initial assessment of the state of a water body regarding the issue in question. After<br />
determining the guideline trigger value the decision tree option should be used to obtain an<br />
appropriate trigger value. The trigger value is determined depending on response of the test site value<br />
to the guideline trigger value. If the test site value is less than the guideline trigger value, showing<br />
there is a low risk that a problem exist, monitoring should continue. In the case that the trigger value<br />
is exceeded, management/remedial action or further site-specific investigation is required, and a<br />
‘potential risk’ exists. Following continuous monitoring, if the indicator values at the site remain as<br />
‘low risk’ the guideline trigger value needs to be refined. In order to derive a low-risk trigger value<br />
(appropriate trigger value), biological and ecological effects data, reference system data, predictive<br />
modelling or professional judgement should be used.<br />
1.3.4 Toxicant in <strong>Water</strong><br />
Toxicants are chemical contaminants such as metals, aromatic hydrocarbons, pesticides and<br />
herbicides that have the potential to exert toxic effects at concentrations, which might be encountered<br />
in the environment. In reference to toxicants the guidelines aim to protect waters from sustained<br />
exposure to toxicants.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
INTRODUCTION 1-7<br />
The guidelines provide trigger values for freshwater and marine water. The guidelines recommended<br />
moving away from relying solely on chemical guideline values for managing water quality, to using<br />
an integrated approach which would involve chemical-specific guidelines coupled with water quality<br />
monitoring, direct toxicity assessment, and biological monitoring. This approach ensures that water<br />
management will focus on protecting the environment instead of focussing on meeting a number.<br />
The trigger values provided by the ANZECC (2000) guidelines are presented as three grades of<br />
trigger values; high, moderate or low reliability. These grades are dependent on the amount of data<br />
available and hence the confidence or reliability of the final figure. Trigger values have also been<br />
derived for four different protection levels; 99%, 95%, 90% and 80%. The protection level signifies<br />
the percentage of species expected to be protected by monitoring concentrations below the define<br />
values. These values were derived using the statistical distribution method.<br />
1.3.5 Toxicants in Sediment<br />
Sediment are important in aquatic ecosystems as they are a source and sink for dissolved<br />
contaminants, they influence surface water quality, and they are a source of bioavailable<br />
contaminants to benthic biota. Consequently it is important to identify areas were sediments present a<br />
likely threat to ecosystem health. Recommended guideline values are provided as interim sediment<br />
quality guideline (ISQG) values. Guidelines are not specified for some contaminants, which reflects<br />
the absence of an adequate data set for that contaminant. A value for this contaminant can be derived<br />
based on the natural background concentration multiplied by an appropriate factor (a value between 2<br />
and 3 is recommended).<br />
1.3.6 Application<br />
A framework is provided for the application of guidelines for the protection of aquatic ecosystems.<br />
The initial step involves two stages, which are common for the application of all of the indicator types<br />
(biological, physiochemical, chemical and sediment);<br />
1 determine the type of water body, the environmental values, the level of protection required, the<br />
environmental concerns, the factors that are affecting the ecosystem and the management goals;<br />
and<br />
2 select the indicator types depending on the first step and then determining the appropriate trigger<br />
values.<br />
For the remaining steps it is convenient to consider guidelines application separately for biological<br />
indicators and non-biological indicators (physical and chemical stressors and toxicants in water and<br />
sediments). For biological indicators decision trees are used to derive the water quality guidelines.<br />
Non-biological indicators are based on given water quality guidelines, however, there is the option to<br />
refine guidelines using a decision tree. The ANZECC (2000) guidelines detail the method to derive<br />
appropriate guidelines for a specific site, instead of using the trigger values provided within the<br />
guidelines.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL 2-1<br />
2 GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL<br />
2.1 Overview<br />
The ongoing management of the data in a digital form is an outcome of the review of historical water<br />
quality data, and the recommendation of future directions for water quality management within the<br />
<strong>Gosford</strong> <strong>City</strong> LGA. The objectives of such a management system are to:<br />
• Manage data within a single system that improves access to the data and efficiency in retrieval<br />
and distribution.<br />
• Set standards and specifications for all future data and for any reformatting of existing data, so<br />
that data relating to a common theme are managed in a consistent and compatible format.<br />
• Provide an efficient data management structure for GCC staff to query, view and analyse data.<br />
This section describes the design of the <strong>Gosford</strong> <strong>Water</strong> <strong>Quality</strong> Database (GWQ), the system<br />
developed by WBM to address the above objectives.<br />
Figure 2.1 <strong>Water</strong> <strong>Quality</strong> Data Management System<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL 2-2<br />
Development of the database involved a number of steps as follows:<br />
• Design the system. The findings from meetings with GCC and a review of the nature of existing<br />
water quality data allowed the identification of the data needs and requirements which provided<br />
the basis for the design;<br />
• Transfer existing water quality data, from both hard copy and existing digital formats, into a<br />
digital format that was compatible with the requirements and specifications of the GWQ system.<br />
This stage also assisted in finalising the standards and specifications for the data, and for testing<br />
and fine-tuning the design before further development of software to enter, access, manipulate<br />
and report on the data;<br />
• Develop software in Microsoft Access for the addition of water quality file records to the<br />
database, including vital quality checks of the data prior to addition to the database to ensure<br />
integrity of the data and consistency with the requirements of the GWQ system. In addition,<br />
applications have been developed in Map Info and Microsoft Excel to facilitate interrogation,<br />
analysis and reporting on the data.<br />
• Handover, installation and training.<br />
Protocols were also developed for the specification of data collection and the digital water quality file<br />
format (*.gwq files) that is used by the water quality data management system.<br />
2.2 General Philosophy of Data Flow and Database Structure<br />
Figure 2.2 illustrates the general process of data flow between GCC, water quality data providers, the<br />
GWQ Database, computer storage and outputs.<br />
Furthermore, the structure of the underlying database is shown in Figure 2.3. The database is centred<br />
around the “Data Items” table. Each entry in the data items table represents a single water quality file<br />
saved in secure storage on GCC’s server. The data set is uniquely identified by a “DataSetID”<br />
number and the name of the associated file in secure storage reflects that number, the site at which<br />
measurements were made, the water quality parameter measured, and the year and month of<br />
measurements. This means that a single file can exist for each unique combination of site, parameter,<br />
year and month combination, provided that the appropriate water quality data is available. Further<br />
information on data naming conventions is provided in the technical reference manual for the GWQ<br />
database (WBM, 2003).<br />
The sites, parameters, data sources and entry personnel tables are provided as ancillary tables to assist<br />
with the integrity checks undertaken on the data and to assist with presentation of results. The system<br />
defaults table contains information on the location of secure storage and a password enabling access<br />
to the database for administrative purposes. The functional groups table is provided to assist with the<br />
grouping of related sites for analysis.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL 2-3<br />
<strong>Water</strong> <strong>Quality</strong> Data<br />
Suppliers<br />
Data Supply<br />
Data Specification<br />
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong><br />
<strong>Water</strong> <strong>Quality</strong> Database (Microsoft Access)<br />
- Checks integrity of incoming text file data<br />
- Copies text file to secure storage on server<br />
- Updates Database with details of saved files<br />
- Entry of raw data and saving in standard format<br />
Secure Storage of<br />
water quality text<br />
files (*.gwq) using<br />
standard naming<br />
protocols<br />
Database<br />
Updating<br />
Database<br />
Interrogation<br />
WQ Map (MapInfo Application)<br />
- Interrogates Database regarding data files in secure storage<br />
- Extracts required data from secure storage<br />
- Organises output of requested data<br />
Outputs<br />
Figure 2.2 Data Flow<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL 2-4<br />
Figure 2.3 Database Structure<br />
Figure 2.4 MapInfo Database Interface<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL 2-5<br />
2.3 Outputs from GWQ<br />
Three types of analyses can be undertaken using the database application. These are:<br />
o <strong>Historical</strong> <strong>Analysis</strong>;<br />
o Yearly <strong>Analysis</strong>; and<br />
o Quarterly <strong>Analysis</strong>.<br />
2.3.1 <strong>Historical</strong> <strong>Analysis</strong><br />
<strong>Historical</strong> analysis outputs the following data in excel spreadsheet format:<br />
• A chart showing data from all sites<br />
• A worksheet summarising all data for that period, for the sites chosen for analysis<br />
• Yearly worksheets summarising data in yearly groups within the selected period, for the sites<br />
chosen for analysis.<br />
A sample historical analysis chart is provided as Figure 2.5.<br />
Figure 2.5 Sample <strong>Historical</strong> Data Chart<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL 2-6<br />
2.3.2 Yearly <strong>Analysis</strong><br />
When yearly analysis is undertaken, an Excel workbook is created with the following individual<br />
worksheets:<br />
For each parameter chosen for analysis:<br />
• A chart showing data from all sites<br />
• A worksheet summarising all data for that period, for the sites chosen for analysis<br />
• A yearly report for each site summarising and charting statistics for the analysis year and the<br />
previous four years.<br />
A sample yearly analysis report is provided as Figure 2.6.<br />
Figure 2.6 Example of a Yearly <strong>Analysis</strong> Report<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
GWQ: A DATA MANAGEMENT AND ASSESSMENT TOOL 2-7<br />
2.3.3 Quarterly <strong>Analysis</strong><br />
When quarterly analysis is undertaken, an Excel workbook is created with the following individual<br />
worksheets:<br />
For each parameter chosen for analysis:<br />
• A chart showing data from all sites<br />
• A worksheet summarising all data for that period, for the sites chosen for analysis<br />
• A quarterly report for each site summarising and charting statistics for the analysis quarter<br />
and the previous four quarters.<br />
Prior to completion of the macro, the user will be prompted to indicate whether a report is to be<br />
printed. If the answer is yes, all quarterly reports will be printed in standard format for inclusion in,<br />
for example, state of the environment reports.<br />
A sample quarterly analysis report is provided as Figure 2.7.<br />
Figure 2.7 Example of a Quarterly <strong>Analysis</strong> Report<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-1<br />
3 RESULTS OF WATER QUALITY DATA ANALYSIS<br />
3.1 Contemporary <strong>Water</strong> <strong>Quality</strong> Results<br />
The most recent water quality monitoring carried out in <strong>Gosford</strong> LGA was undertaken by Assoc.<br />
Prof. Dominic Cheng of Ecoscience Technology (University of Technology, Sydney). Monitoring<br />
was carried out at ten (10) sites within Brisbane <strong>Water</strong> and the coastal lagoons, as identified in Figure<br />
3.1. Monitoring was on a monthly basis between August 1999 and June 2002. Details of the<br />
monitoring results are found in Ecoscience Technology (2002). The general results of this<br />
monitoring program are described in the Sections below. The results have been obtained using the<br />
yearly and quarterly reporting tools of GWQ, as described in Section 2.3. <strong>Analysis</strong> is thus<br />
provided for annual comparisons for the entire dataset, and for quarterly comparisons over the last 12<br />
month period (2001 / 2002). Median values for annual results have been reported to reflect a more<br />
‘typical’ value within the waterways, whereas mean values are reported for the quarterly results given<br />
the lack of statistical data (i.e. generally only three records per quarter).<br />
The quarterly results are slighted skewed by the fact that the Jan – Mar 2002 period contained only<br />
one record (other quarters contained either three or four records). Therefore, care should be taken<br />
when interpreting the results. This problem highlights the importance of consistent data collection<br />
throughout the monitoring period.<br />
Figure 3.1 Sites for Most Recent (Cheng) <strong>Water</strong> <strong>Quality</strong> Monitoring Program<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-2<br />
3.1.1 Physical Parameters<br />
3.1.1.1 Temperature<br />
Median annual temperatures for the <strong>Gosford</strong> waterways are presented in Table 3.1, while mean<br />
quarterly temperatures are presented in Table 3.2.<br />
The annual results show typically warmer temperatures in 1999/2000 compared to the other two<br />
years. This would be due to the summer biasing of the 9 records that were collected during that year.<br />
Given the natural variability in temperature, no definitive temporal trend was identified.<br />
On a quarterly basis, the results show a distinctive change associated with seasonal variations of<br />
ambient air temperature. However, there was not a significant difference in mean temperature<br />
between the Apr – Jun 2002 period and the previous Apr – Jun 2001 period, with most results within<br />
+/- 1°C.<br />
Table 3.1<br />
Annual Medians for Temperature<br />
Temperature (Degrees C)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 20.2 17.0 19.9 <br />
Site : 78 - Narara Creek Entrance 19.6 18.0 22.0 <br />
Site : 79 - Erina Creek Entrance 19.6 18.5 21.3 <br />
Site : 80 - Kincumber Creek Entrance 18.3 18.4 22.0 <br />
Site : 81 - Cockle Creek 19.3 18.5 22.0 <br />
Site : 82 - Woy Woy Creek 20.0 18.0 23.0 <br />
Site : 83 - Wamberal Lagoon 18.4 15.8 23.3 <br />
Site : 84 - Terrigal Lagoon 18.6 15.1 23.3 <br />
Site : 85 - Avoca Lagoon 19.1 16.1 23.8 <br />
Site : 86 - Cockrone Lagoon 18.6 17.0 22.9 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.2<br />
Quarterly Means for Temperature<br />
Temperature (Degrees C)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 17.7 24.1 21.7 16.3 17.8 seasonal<br />
Site : 78 - Narara Creek Entrance 17.0 24.8 22.8 16.2 15.6 seasonal<br />
Site : 79 - Erina Creek Entrance 17.1 24.5 23.3 16.2 16.2 seasonal<br />
Site : 80 - Kincumber Creek Entrance 16.0 23.9 22.1 14.6 14.8 seasonal<br />
Site : 81 - Cockle Creek 17.6 24.0 22.2 16.3 19.2 seasonal<br />
Site : 82 - Woy Woy Creek 16.9 24.1 23.1 16.6 16.9 seasonal<br />
Site : 83 - Wamberal Lagoon 16.0 23.5 21.9 15.5 16.6 seasonal<br />
Site : 84 - Terrigal Lagoon 15.7 23.4 22.0 15.5 15.2 seasonal<br />
Site : 85 - Avoca Lagoon 16.2 23.9 22.8 15.4 16.3 seasonal<br />
Site : 86 - Cockrone Lagoon 15.7 24.6 22.5 15.4 14.8 seasonal<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-3<br />
3.1.1.2 pH<br />
Median annual pH for the <strong>Gosford</strong> waterways is presented in Table 3.3, while mean quarterly pH is<br />
presented in Table 3.4. pH levels tend to be quite variable, although levels in the last year (2001 /<br />
2002) were generally slightly higher than previous years (with the obvious exception of Site 80:<br />
Kincumber Ck entrance).<br />
pH levels were generally higher in the coastal lagoons that the Brisbane <strong>Water</strong> sites, particularly<br />
Cockrone Lagoon. The elevated pH levels in these type of environments is generally attributed to<br />
high rates of photosynthesis by micro and macro algae.<br />
On a quarterly basis, pH levels varied considerably. The results suggest a quasi-seasonal variation,<br />
with typically higher concentrations in the summer months, and lower concentrations in the winter<br />
months.<br />
Table 3.3<br />
Annual Medians for pH<br />
pH<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 8.51 8.11 8.10 <br />
Site : 78 - Narara Creek Entrance 8.15 7.82 7.98 <br />
Site : 79 - Erina Creek Entrance 8.22 7.93 7.80 <br />
Site : 80 - Kincumber Creek Entrance 7.59 7.70 8.00 <br />
Site : 81 - Cockle Creek 8.26 8.14 8.15 <br />
Site : 82 - Woy Woy Creek 8.23 7.74 7.78 <br />
Site : 83 - Wamberal Lagoon 8.67 8.20 8.12 <br />
Site : 84 - Terrigal Lagoon 8.48 7.97 8.17 <br />
Site : 85 - Avoca Lagoon 8.60 8.21 8.39 <br />
Site : 86 - Cockrone Lagoon 8.92 8.64 8.80 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.4<br />
Quarterly Means for pH<br />
pH<br />
Site No. and Location<br />
Apr – Jun Jan – Mar Oct – Dec Jul – Sep Apr – Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 – Booker Bay 7.81 8.21 8.73 8.57 8.37 Seasonal<br />
Site : 78 – Narara Creek Entrance 7.47 8.06 8.59 8.28 7.88 Seasonal<br />
Site : 79 – Erina Creek Entrance 7.16 8.34 8.58 8.21 8.07 Seasonal<br />
Site : 80 – Kincumber Creek Entrance 6.97 8.26 7.86 7.72 7.43 Seasonal<br />
Site : 81 – Cockle Creek 7.61 8.22 8.57 8.37 8.40 Seasonal<br />
Site : 82 – Woy Woy Creek 7.49 7.92 8.51 8.37 7.98 Seasonal<br />
Site : 83 – Wamberal Lagoon 7.45 7.97 9.11 8.90 8.24 Seasonal<br />
Site : 84 – Terrigal Lagoon 7.38 7.73 8.57 8.57 7.97 Seasonal<br />
Site : 85 – Avoca Lagoon 7.81 7.51 9.40 8.97 8.22 Seasonal<br />
Site : 86 – Cockrone Lagoon 8.59 7.23 10.13 8.98 8.16 Seasonal<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-4<br />
3.1.1.3 Turbidity<br />
Median annual turbidity for the <strong>Gosford</strong> waterways is presented in Table 3.5, while mean quarterly<br />
turbidity is presented in Table 3.6. Turbidity is very much influenced by catchment runoff events,<br />
meaning that periods of higher rainfall generally result in higher turbidity levels within receiving<br />
waterways. Turbidity can also be influenced by the amount of algae growing within the water<br />
column. Trends in the annual medians for water quality would likely be attributed to the degree of<br />
catchment runoff experienced at those sites during the monitoring period. Sites experiencing the<br />
higher turbidity levels are generally near the outlets of creeks, and thus would be quite influenced by<br />
runoff flows. Turbidity can also be influenced by wind turbulence and resuspension of bed<br />
sediments. This is particularly the case in the coastal lagoons when water levels are low and depths<br />
around foreshore fringes are generally quite shallow.<br />
The quarterly analysis also highlights the variability in turbidity levels, with no consistent pattern<br />
over the preceding 12 months. Rainfall records for the relevant periods are also presented in the<br />
tables below. The most significant period of rainfall was Jan-Mar 2002, with over 700mm of rain.<br />
Unfortunately, only one water quality monitoring event coincided with this period, so wet-weather<br />
correlations are difficult to interpret.<br />
Table 3.5<br />
Annual Medians for Turbidity<br />
Turbidity (NTU)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 2.0 3.0 1.8 <br />
Site : 78 - Narara Creek Entrance 9.0 11.5 3.8 <br />
Site : 79 - Erina Creek Entrance 11.0 9.0 7.6 <br />
Site : 80 - Kincumber Creek Entrance 19.0 13.0 6.3 <br />
Site : 81 - Cockle Creek 3.0 6.5 2.4 <br />
Site : 82 - Woy Woy Creek 6.0 11.5 4.4 <br />
Site : 83 - Wamberal Lagoon 3.0 7.0 3.8 <br />
Site : 84 - Terrigal Lagoon 5.0 9.0 6.3 <br />
Site : 85 - Avoca Lagoon 4.0 5.5 2.6 <br />
Site : 86 - Cockrone Lagoon 6.0 4.0 1.7 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.6<br />
Quarterly Means for Turbidity<br />
Turbidity (NTU)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 1.5 3.0 2.0 2.0 2.7 Rain dep<br />
Site : 78 - Narara Creek Entrance 20.3 6.0 4.3 11.0 14.3 Rain dep<br />
Site : 79 - Erina Creek Entrance 23.0 7.0 8.3 9.3 16.7 Rain dep<br />
Site : 80 - Kincumber Creek Entrance 39.8 13.0 14.0 46.0 9.3 Rain dep<br />
Site : 81 - Cockle Creek 3.5 1.0 2.7 3.7 8.3 Rain dep<br />
Site : 82 - Woy Woy Creek 15.0 6.0 8.3 4.7 18.7 Rain dep<br />
Site : 83 - Wamberal Lagoon 11.0 5.0 2.3 2.7 7.3 Rain dep<br />
Site : 84 - Terrigal Lagoon 9.3 5.0 4.3 8.0 14.7 Rain dep<br />
Site : 85 - Avoca Lagoon 7.8 18.0 3.3 2.7 7.0 Rain dep<br />
Site : 86 - Cockrone Lagoon 7.3 26.0 1.3 7.3 7.7 Rain dep<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-5<br />
3.1.1.4 Secchi Depth<br />
Secchi depth is a measure of the amount of light penetration through the water column, and is similar<br />
to turbidity in this regard. The annual medians for secchi depth are shown in Table 3.7. Data<br />
collection of secchi depth was terminated in September 2000, after only 15 months of monitoring.<br />
Therefore, interpretation of the results is limited, and no recent quarterly values are available.<br />
The annual data shows that significant improvements in secchi depth occurred between 1999 / 2000<br />
and 2000/2001 at Erina Ck, Woy Woy Ck, Wamberal Lagoons and Terrigal Lagoon. The accuracy<br />
of this trend is questionable, however, due to the limited data set within the later period.<br />
Table 3.7<br />
Annual Medians for Secchi Depth<br />
Secchi Depth (metres)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=0 n=3 n=8 Trend<br />
Site : 77 - Booker Bay - 2.02 2.02 <br />
Site : 78 - Narara Creek Entrance - 1.45 1.44 <br />
Site : 79 - Erina Creek Entrance - 1.50 0.90 <br />
Site : 80 - Kincumber Creek Entrance - 0.90 0.70 <br />
Site : 81 - Cockle Creek - 1.95 1.73 <br />
Site : 82 - Woy Woy Creek - 2.00 1.00 <br />
Site : 83 - Wamberal Lagoon - 2.00 1.25 <br />
Site : 84 - Terrigal Lagoon - 1.80 0.66 <br />
Site : 85 - Avoca Lagoon - 2.00 2.23 <br />
Site : 86 - Cockrone Lagoon - 2.50 2.20 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-6<br />
3.1.1.5 Salinity<br />
Median annual salinity for the <strong>Gosford</strong> waterways is presented in Table 3.8, while mean quarterly<br />
salinity is presented in Table 3.9.<br />
Salinity responds to freshwater catchment inflows, and is dependent on the ability of the tides to<br />
restore oceanic waters following fresh events. The influence of catchment runoff on salinity is<br />
particularly highlighted in the quarterly results. Low salinity levels (< 15ppt) at the sites near creek<br />
outlets occur following catchment runoff. Tidal flushing then restores oceanic salt levels (~35ppt)<br />
over the following months. Salinity was generally lowest in the period Apr – Jun 2002, following<br />
extensive rainfall in February, March and April 2002.<br />
Of particular interest in the data is the evidence of Cockle Creek behaving as a backwater area (with<br />
sustained higher salinity levels during general catchment runoff events). Also, the behaviour of<br />
salinity in the coastal lagoons is further complicated by the lagoon entrance conditions. When closed,<br />
water levels in the lagoons increase (reducing salinity) until the entrance berm is breached, the lagoon<br />
is drained, and oceanic waters are flushed into the lagoon (before the entrance closes once again).<br />
Table 3.8<br />
Annual Medians for Salinity<br />
Salinity (ppt)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 34.4 30.4 28.7 <br />
Site : 78 - Narara Creek Entrance 27.0 26.0 25.7 <br />
Site : 79 - Erina Creek Entrance 24.2 26.8 25.4 <br />
Site : 80 - Kincumber Creek Entrance 18.7 24.2 27.1 <br />
Site : 81 - Cockle Creek 33.2 30.5 27.2 <br />
Site : 82 - Woy Woy Creek 30.2 27.1 24.4 <br />
Site : 83 - Wamberal Lagoon 15.9 6.1 15.7 <br />
Site : 84 - Terrigal Lagoon 16.3 9.3 9.4 <br />
Site : 85 - Avoca Lagoon 13.2 16.8 18.6 <br />
Site : 86 - Cockrone Lagoon 15.7 7.2 14.7 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.9<br />
Quarterly Means for Salinity<br />
Salinity (ppt)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 31.9 34.4 36.1 35.2 32.8 Rain dep.<br />
Site : 78 - Narara Creek Entrance 8.8 27.0 34.5 26.6 16.5 Rain dep<br />
Site : 79 - Erina Creek Entrance 6.0 25.7 34.1 24.5 13.4 Rain dep<br />
Site : 80 - Kincumber Creek Entrance 12.6 26.9 32.8 2.1 17.0 Rain dep<br />
Site : 81 - Cockle Creek 30.7 32.3 36.1 34.5 30.5 Rain dep<br />
Site : 82 - Woy Woy Creek 16.2 26.8 35.1 31.4 24.3 Rain dep<br />
Site : 83 - Wamberal Lagoon 11.8 34.3 18.2 14.2 15.5 Rain dep<br />
Site : 84 - Terrigal Lagoon 17.9 23.1 16.4 13.4 12.7 Rain dep<br />
Site : 85 - Avoca Lagoon 14.0 23.0 12.5 13.3 19.4 Rain dep<br />
Site : 86 - Cockrone Lagoon 16.2 24.4 14.8 16.5 14.5 Rain dep<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-7<br />
3.1.1.6 Dissolved Oxygen<br />
Median annual dissolved oxygen for the <strong>Gosford</strong> waterways is presented in Table 3.10, while mean<br />
quarterly dissolved oxygen is presented in Table 3.11. Dissolved oxygen within the water is<br />
consumed by respiration of organic matter. Heterotrophic conditions within the waterways result in<br />
reducing oxygen levels.<br />
The quarterly analysis suggests that the dissolved oxygen levels are at least quasi-seasonal, with<br />
notable decreases over the summer months, only to return to high levels during the last quarter.<br />
Catchment runoff during the last quarter (as evidenced by monthly rainfall records and associated<br />
salinity levels) probably contributed to the sudden increase in dissolved oxygen at most sites,<br />
particularly Kincumber Creek, Avoca Lagoon and Cockrone Lagoon.<br />
Possible reasons for the seasonal variation in dissolved oxygen could be related to the boom and bust<br />
cycle of algae, where elevated temperatures in the summer make conditions ideal for algal growth,<br />
but when nutrients become limiting, the bloom dies off, and the organic matter decay (consuming<br />
oxygen in the process).<br />
Table 3.10 Annual Medians for Dissolved Oxygen<br />
Dissolved Oxygen (mg/L)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 6.71 7.18 7.30 <br />
Site : 78 - Narara Creek Entrance 5.76 6.60 6.25 <br />
Site : 79 - Erina Creek Entrance 5.51 6.37 6.30 <br />
Site : 80 - Kincumber Creek Entrance 5.50 6.53 6.80 <br />
Site : 81 - Cockle Creek 6.56 8.14 7.40 <br />
Site : 82 - Woy Woy Creek 5.60 6.00 5.25 <br />
Site : 83 - Wamberal Lagoon 6.90 9.40 7.50 <br />
Site : 84 - Terrigal Lagoon 6.84 7.30 6.35 <br />
Site : 85 - Avoca Lagoon 6.20 8.10 6.65 <br />
Site : 86 - Cockrone Lagoon 7.17 8.22 7.65 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.11 Quarterly Means for Dissolved Oxygen<br />
Dissolved Oxygen (mg/L)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 6.87 5.84 6.72 6.92 6.93 Seasonal<br />
Site : 78 - Narara Creek Entrance 6.12 4.56 5.86 5.80 6.93 Seasonal<br />
Site : 79 - Erina Creek Entrance 6.16 4.80 5.65 6.22 6.84 Seasonal<br />
Site : 80 - Kincumber Creek Entrance 5.50 2.76 3.40 6.68 5.99 Seasonal<br />
Site : 81 - Cockle Creek 7.50 4.46 5.68 6.96 8.72 Seasonal<br />
Site : 82 - Woy Woy Creek 6.35 4.03 4.55 5.87 6.26 Seasonal<br />
Site : 83 - Wamberal Lagoon 7.22 4.71 5.91 7.34 9.48 Seasonal<br />
Site : 84 - Terrigal Lagoon 7.27 5.58 5.87 7.22 7.33 Seasonal<br />
Site : 85 - Avoca Lagoon 7.53 2.60 5.69 7.19 8.16 Seasonal<br />
Site : 86 - Cockrone Lagoon 8.86 2.02 6.96 7.70 7.54 Seasonal<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-8<br />
3.1.2 Chemical Parameters<br />
3.1.2.1 Ammonia<br />
Annual median concentrations of ammonia in the <strong>Gosford</strong> waters is shown in Table 3.12, while the<br />
quarterly averages of ammonia for the past 15 months is shown in Table 3.13. The annual data<br />
suggests that there has not been any notable trends in ammonia concentrations, except possibly for<br />
Avoca Lagoon, where the median concentration essentially halved between 1999/2000 and<br />
2001/2002. The reason for this reduction is not known, and was not consistent with trends at other<br />
locations, or with overall rainfall / runoff patterns.<br />
The quarterly analysis shows that high concentrations were recorded in the Brisbane <strong>Water</strong> sites<br />
during the last quarter (Apr-Jun 2002), however, notably higher ammonia concentrations were<br />
recorded in the coastal lagoons during the preceding quarter (Jan-Mar 2002, although only one record<br />
was taken in this period, so caution is required in interpreting the results). It is likely that the variable<br />
nature of ammonia concentrations is closely linked with catchment runoff (given that significant<br />
runoff occurred between February and Apr 2002), however, the chemical processes within the<br />
waterways would obscure this connection to some degree.<br />
Table 3.12 Annual Medians for Ammonia<br />
Ammonia (mg/L)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 0.011 0.013 0.005 <br />
Site : 78 - Narara Creek Entrance 0.019 0.027 0.015 <br />
Site : 79 - Erina Creek Entrance 0.019 0.021 0.028 <br />
Site : 80 - Kincumber Creek Entrance 0.026 0.029 0.019 <br />
Site : 81 - Cockle Creek 0.013 0.014 0.010 <br />
Site : 82 - Woy Woy Creek 0.027 0.025 0.020 <br />
Site : 83 - Wamberal Lagoon 0.015 0.016 0.024 <br />
Site : 84 - Terrigal Lagoon 0.013 0.017 0.019 <br />
Site : 85 - Avoca Lagoon 0.012 0.016 0.024 <br />
Site : 86 - Cockrone Lagoon 0.010 0.010 0.008 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.13 Quarterly Means for Ammonia<br />
Ammonia (mg/L)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 0.022 0.008 0.010 0.010 0.013 Variable<br />
Site : 78 - Narara Creek Entrance 0.046 0.017 0.017 0.018 0.024 Variable<br />
Site : 79 - Erina Creek Entrance 0.047 0.019 0.018 0.015 0.024 Variable<br />
Site : 80 - Kincumber Creek Entrance 0.067 0.028 0.022 0.021 0.034 Variable<br />
Site : 81 - Cockle Creek 0.034 0.013 0.012 0.011 0.015 Variable<br />
Site : 82 - Woy Woy Creek 0.048 0.027 0.027 0.015 0.024 Variable<br />
Site : 83 - Wamberal Lagoon 0.018 0.049 0.022 0.010 0.019 Variable<br />
Site : 84 - Terrigal Lagoon 0.019 0.044 0.012 0.011 0.015 Variable<br />
Site : 85 - Avoca Lagoon 0.023 0.116 0.012 0.009 0.021 Variable<br />
Site : 86 - Cockrone Lagoon 0.020 0.132 0.010 0.008 0.011 Variable<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-9<br />
3.1.2.2 Oxidised Nitrogen<br />
Annual median concentrations of oxidised nitrogen (i.e. nitrates and nitrites) in the <strong>Gosford</strong> waters is<br />
shown in Table 3.14, while the quarterly averages of oxidised nitrogen for the past 15 months is<br />
shown in Table 3.15. The annual results show that the sites located at the creek entrances (i.e.<br />
Narara, Erina, Kincumber and Woy Woy Creeks) all have relatively elevated concentrations of<br />
oxidised nitrogen.<br />
The quarterly results show variable concentrations throughout the 15 month period, which may be a<br />
function of the amount of catchment runoff during preceding weeks or months. Highest<br />
concentrations were recorded during the last quarter (Apr – Jun 2002) following extensive rainfall<br />
during the February to April 2002 period. Oxidised nitrogen is generated through the nitrification of<br />
ammonia, and so its presence in the environment can be delayed somewhat due to the time taken for<br />
such chemical processes to occur.<br />
Table 3.14 Annual Medians for Oxidised Nitrogen<br />
Oxidised Nitrogen (mg/L)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 0.021 0.017 0.021 <br />
Site : 78 - Narara Creek Entrance 0.049 0.048 0.036 <br />
Site : 79 - Erina Creek Entrance 0.052 0.048 0.042 <br />
Site : 80 - Kincumber Creek Entrance 0.049 0.049 0.040 <br />
Site : 81 - Cockle Creek 0.036 0.032 0.020 <br />
Site : 82 - Woy Woy Creek 0.040 0.051 0.036 <br />
Site : 83 - Wamberal Lagoon 0.027 0.031 0.042 <br />
Site : 84 - Terrigal Lagoon 0.036 0.038 0.046 <br />
Site : 85 - Avoca Lagoon 0.041 0.031 0.032 <br />
Site : 86 - Cockrone Lagoon 0.031 0.020 0.020 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.15 Quarterly Means for Oxidised Nitrogen<br />
Oxidised Nitrogen (mg/L)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 0.034 0.022 0.018 0.017 0.023 Variable<br />
Site : 78 - Narara Creek Entrance 0.145 0.034 0.049 0.042 0.057 Variable<br />
Site : 79 - Erina Creek Entrance 0.091 0.024 0.049 0.031 0.047 Variable<br />
Site : 80 - Kincumber Creek Entrance 0.135 0.045 0.059 0.042 0.056 Variable<br />
Site : 81 - Cockle Creek 0.072 0.036 0.043 0.026 0.035 Variable<br />
Site : 82 - Woy Woy Creek 0.082 0.040 0.041 0.024 0.039 Variable<br />
Site : 83 - Wamberal Lagoon 0.049 0.028 0.025 0.025 0.040 Variable<br />
Site : 84 - Terrigal Lagoon 0.082 0.026 0.026 0.033 0.056 Variable<br />
Site : 85 - Avoca Lagoon 0.079 0.066 0.029 0.034 0.052 Variable<br />
Site : 86 - Cockrone Lagoon 0.069 0.070 0.025 0.026 0.032 Variable<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-10<br />
3.1.2.3 Total Nitrogen<br />
Annual median Total Nitrogen (TN) concentrations in the <strong>Gosford</strong> waterways are presented in Table<br />
3.16, while quarterly average concentrations are shown in Table 3.17. Total nitrogen tends to be a<br />
parameter that can be highly variable, particularly in semi-enclosed estuaries like Brisbane <strong>Water</strong>,<br />
where the level is constantly being affected by oceanic inputs and catchment runoff. In general, the<br />
TN concentrations in Brisbane <strong>Water</strong> tend to be lower than in the coastal lagoons, due to the greater<br />
and permanent tidal flushing of the semi-enclosed estuary, compared to the intermittently closed<br />
coastal lagoons.<br />
The quarterly results highlight the highly variable nature of TN concentrations, particularly at the<br />
creek sites and in the coastal lagoons. The creek sites generally exhibited higher TN concentrations<br />
following rainfall. However, the coastal lagoons showed greater variability during dry weather times,<br />
possibly suggesting alternative nitrogen-based processes within the lagoons. Haines (in prep.) has<br />
found that many coastal lagoons, which are mostly closed to the ocean, exhibit highly variable<br />
nitrogen concentrations that are independent of catchment runoff events, and postulates sediment<br />
interactions as a significant nitrogen input to such lagoons.<br />
Table 3.16 Annual Medians for Total Nitrogen<br />
Total Nitrogen (mg/L)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 1.10 0.70 0.90 <br />
Site : 78 - Narara Creek Entrance 1.10 1.05 1.50 <br />
Site : 79 - Erina Creek Entrance 1.00 1.15 1.20 <br />
Site : 80 - Kincumber Creek Entrance 1.30 1.00 0.40 <br />
Site : 81 - Cockle Creek 0.90 1.05 0.80 <br />
Site : 82 - Woy Woy Creek 0.85 1.63 0.90 <br />
Site : 83 - Wamberal Lagoon 1.80 2.05 1.80 <br />
Site : 84 - Terrigal Lagoon 1.10 2.65 1.40 <br />
Site : 85 - Avoca Lagoon 1.70 1.55 1.10 <br />
Site : 86 - Cockrone Lagoon 0.70 1.15 1.40 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.17 Quarterly Means for Total Nitrogen<br />
Total Nitrogen (mg/L)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 1.00 0.40 0.90 1.47 0.70 Highly var<br />
Site : 78 - Narara Creek Entrance 4.15 0.40 0.80 1.27 4.43 Highly var<br />
Site : 79 - Erina Creek Entrance 2.35 1.00 0.80 1.00 18.00* Highly var<br />
Site : 80 - Kincumber Creek Entrance 2.33 0.70 1.00 3.10 2.70 Highly var<br />
Site : 81 - Cockle Creek 0.83 0.50 1.03 1.50 1.00 Highly var<br />
Site : 82 - Woy Woy Creek 1.20 0.60 0.73 2.63 1.47 Highly var<br />
Site : 83 - Wamberal Lagoon 2.68 0.80 2.03 4.30 2.20 Highly var<br />
Site : 84 - Terrigal Lagoon 1.20 0.50 1.63 2.57 5.80 Highly var<br />
Site : 85 - Avoca Lagoon 1.60 0.30 0.97 3.80 0.97 Highly var<br />
Site : 86 - Cockrone Lagoon 1.73 0.80 0.37 1.53 4.30 Highly var<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
* value distorted due to very high concentration (52.4mg/L) measured in May 2001.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-11<br />
3.1.2.4 Orthophosphate<br />
Annual median orthophosphate concentrations for sites located in the <strong>Gosford</strong> waterways are<br />
presented in Table 3.18, while quarterly mean concentrations for the last 15 months of monitoring are<br />
presented in Table 3.19. Annual data suggests that there has been no distinguishable overall trend in<br />
phosphate concentrations over the last 3 years of monitoring, with all concentrations generally quite<br />
low (and probably limiting primary productivity in most circumstances).<br />
The quarterly analysis shows appreciably higher phosphate concentrations following periods of<br />
significant rainfall (and runoff), with elevated concentrations at all sites during the April to June 2002<br />
quarter (when over 800mm of rain fell between February and April) and also the April to June 2001<br />
quarter (when 770mm of rain fell between February and May). Inorganic phosphorus (or<br />
orthophosphate) is a typical urban pollutant, generated by numerous anthropogenic activities<br />
including domestic gardening (i.e. fertilising).<br />
Table 3.18 Annual Medians for Orthophosphate<br />
Orthophosphate (mg/L)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 0.009 0.012 0.002 <br />
Site : 78 - Narara Creek Entrance 0.009 0.017 0.010 <br />
Site : 79 - Erina Creek Entrance 0.011 0.014 0.013 <br />
Site : 80 - Kincumber Creek Entrance 0.013 0.014 0.006 <br />
Site : 81 - Cockle Creek 0.010 0.015 0.005 <br />
Site : 82 - Woy Woy Creek 0.012 0.017 0.017 <br />
Site : 83 - Wamberal Lagoon 0.006 0.009 0.005 <br />
Site : 84 - Terrigal Lagoon 0.006 0.011 0.007 <br />
Site : 85 - Avoca Lagoon 0.006 0.010 0.005 <br />
Site : 86 - Cockrone Lagoon 0.005 0.010 0.004 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.19 Quarterly Means for Orthophosphate<br />
Orthophosphate (mg/L)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 0.010 0.002 0.011 0.011 0.011 Variable<br />
Site : 78 - Narara Creek Entrance 0.023 0.007 0.007 0.013 0.015 Rain dep.<br />
Site : 79 - Erina Creek Entrance 0.030 0.009 0.009 0.011 0.021 Rain dep.<br />
Site : 80 - Kincumber Creek Entrance 0.032 0.007 0.010 0.024 0.020 Rain dep.<br />
Site : 81 - Cockle Creek 0.027 0.006 0.007 0.013 0.019 Rain dep.<br />
Site : 82 - Woy Woy Creek 0.031 0.004 0.016 0.017 0.024 Rain dep.<br />
Site : 83 - Wamberal Lagoon 0.015 0.002 0.006 0.004 0.012 Rain dep.<br />
Site : 84 - Terrigal Lagoon 0.038 0.010 0.006 0.006 0.014 Rain dep.<br />
Site : 85 - Avoca Lagoon 0.020 0.003 0.006 0.004 0.014 Rain dep.<br />
Site : 86 - Cockrone Lagoon 0.018 0.004 0.005 0.004 0.010 Rain dep.<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-12<br />
3.1.2.5 Total Phosphorus<br />
Median annual Total Phosphorus (TP) concentrations for the <strong>Gosford</strong> waterways is presented in<br />
Table 3.20, while mean quarterly TP is presented in Table 3.21. Like many other water quality<br />
parameters, TP concentrations are quite variable from one year to the next. Based on the quarterly TP<br />
results, concentrations appear to be quite dependent on rainfall and runoff, with notably higher TP<br />
concentrations recorded during the last quarter (April – June 2002), following substantial rainfall and<br />
runoff from the catchment.<br />
Phosphorus can be attached to sediment, and hence an increase in sediment within the water column<br />
can sometimes translate to an increase in total phosphorus. Phosphorus processes within the<br />
waterway are more simplistic than the nitrogen processes. Hence, the relationships between<br />
phosphorus and rainfall are generally more robust.<br />
Table 3.20 Annual Medians for Total Phosphorus<br />
Total Phosphorus (mg/L)<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 0.030 0.055 0.030 <br />
Site : 78 - Narara Creek Entrance 0.050 0.065 0.040 <br />
Site : 79 - Erina Creek Entrance 0.050 0.065 0.070 <br />
Site : 80 - Kincumber Creek Entrance 0.080 0.085 0.060 <br />
Site : 81 - Cockle Creek 0.040 0.080 0.050 <br />
Site : 82 - Woy Woy Creek 0.030 0.110 0.120 <br />
Site : 83 - Wamberal Lagoon 0.040 0.055 0.040 <br />
Site : 84 - Terrigal Lagoon 0.030 0.065 0.060 <br />
Site : 85 - Avoca Lagoon 0.030 0.050 0.040 <br />
Site : 86 - Cockrone Lagoon 0.030 0.045 0.030 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.21 Quarterly Means for Total Phosphorus<br />
Total Phosphorus (mg/L)<br />
Site No. and Location<br />
Apr - Jun Jan - Mar Oct - Dec Jul - Sep Apr - Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 - Booker Bay 0.038 0.010 0.053 0.043 0.050 variable<br />
Site : 78 - Narara Creek Entrance 0.078 0.010 0.037 0.050 0.057 Rain dep.<br />
Site : 79 - Erina Creek Entrance 0.123 0.030 0.050 0.043 0.077 Rain dep.<br />
Site : 80 - Kincumber Creek Entrance 0.143 0.010 0.053 0.137 0.073 Rain dep.<br />
Site : 81 - Cockle Creek 0.175 0.010 0.033 0.047 0.067 Rain dep.<br />
Site : 82 - Woy Woy Creek 0.128 0.020 0.038 0.170 0.097 Rain dep.<br />
Site : 83 - Wamberal Lagoon 0.085 0.020 0.047 0.020 0.060 Rain dep.<br />
Site : 84 - Terrigal Lagoon 0.230 0.040 0.027 0.027 0.073 Rain dep.<br />
Site : 85 - Avoca Lagoon 0.100 0.010 0.027 0.023 0.067 Rain dep.<br />
Site : 86 - Cockrone Lagoon 0.103 0.010 0.030 0.020 0.050 Rain dep.<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-13<br />
3.1.3 Compound <strong>Water</strong> <strong>Quality</strong> Index<br />
Considerable insight to the water quality of the <strong>Gosford</strong> waterways can be obtained through<br />
investigation of the various water quality parameters, as discussed in the preceding Sections of this<br />
report. However, it is most useful to simplify the information into a single parameter, which can be<br />
reported to the community and <strong>Council</strong>lors to give an overall indication of the general water quality<br />
condition.<br />
In order to obtain a ‘Compound <strong>Water</strong> <strong>Quality</strong> Index’, the data from a range of water quality<br />
parameters needs to be synthesised and considered concurrently. For each major water quality<br />
parameter, the measured concentration is compared to a criteria set, and categorised into one of four<br />
different ranges. The overall water quality score can be determined by applying a value to each of the<br />
ranges (1 = good; 4 = highly degraded), summing the individual scores, and then dividing by the<br />
number of parameters included in the assessment.<br />
Table 3.22 presents the key water quality parameters and the interim relative ranges (and scores) for<br />
each as applicable to the <strong>Gosford</strong> waterways. Although Chlorophyll-a was not included in the most<br />
recent water quality monitoring program (as described in the previous Sections of this report), it has<br />
been included in the matrix below for future reference, as it is an extremely valuable water quality<br />
indicator that is likely to be included as part of any future monitoring program.<br />
Table 3.22 <strong>Gosford</strong> <strong>Water</strong> <strong>Quality</strong> Index Range Definition Matrix<br />
Parameter Range 1<br />
(value = 1)<br />
Range 2<br />
(value = 2)<br />
Range 3<br />
(value = 3)<br />
Range 4<br />
(value = 4)<br />
Turbidity 0 – 5 NTU 5 – 15 NTU 15 – 30 NTU > 30 NTU<br />
Dissolved Oxygen > 6.5 mg/L 4.0 – 6.5 mg/L 2.0 – 4.0 mg/L < 2.0 mg/L<br />
Ammonia 0 – 0.01 mg/L 0.01 – 0.03 mg/L 0.03 – 0.05 mg/L > 0.05 mg/L<br />
Oxidised Nitrogen 0 – 0.02 mg/L 0.02 – 0.05 mg/L 0.05 – 0.10 mg/L > 0.10 mg/L<br />
Total Nitrogen 0 – 1.0 mg/L 1.0 – 1.5 mg/L 1.5 – 2.0 mg/L > 2.0 mg/L<br />
Orthophosphate 0 –0.01 mg/L 0.01 – 0.03 mg/L 0.03 – 0.05 mg/L > 0.05 mg/L<br />
Total Phosphorus 0 – 0.05 mg/L 0.05 – 0.10 mg/L 0.10 – 0.20 mg/L > 0.20 mg/L<br />
Chlorophyll-a 0 – 2 µg/L 2 – 5 µg/L 5 – 10 µg/L > 10 µg/L<br />
<strong>Water</strong>ways that exhibit water quality concentrations within Range 1 can be considered to be in<br />
relatively good condition (with respect to water quality at least). If waterways start to exhibit a large<br />
number of Range 3 or Range 4 values, then it would tend to indicate a more degraded system (which<br />
is likely to have follow-on effects to the general aquatic ecosystem). The values provided in Table<br />
3.22 are intended to provide a more sites-specific assessment of water quality, as recommended by<br />
ANZECC (2000). In determining the values, consideration was given to the default trigger values for<br />
physical and chemical stressors (as defined in ANZECC, 2000), along with an appreciation of the<br />
historical water quality results.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-14<br />
From an objectives viewpoint, the primary goal would be to ensure that all water quality parameters<br />
remain within Range 1. However, it is recognised that this would not be achievable (in the short term<br />
at least) due to the considerable amount of urban development within the catchment. Therefore, from<br />
time to time, values within Range 2 would be acceptable (eg. 25% exceedance of the Range 1 upper<br />
bound).<br />
The resulting <strong>Water</strong> <strong>Quality</strong> Index for the <strong>Gosford</strong> waters over the last three years of monitoring is<br />
presented in Table 3.23. To simplify the <strong>Water</strong> <strong>Quality</strong> Index further, a Scorecard approach has been<br />
developed that provides an overall water quality score (out of 10). The Scorecard Index is presented<br />
in Table 3.24, while the final scores for the <strong>Gosford</strong> waterways are presented in Table 3.25. Intervals<br />
between scores in Table 3.24 are not even, with a narrower range at the more pristine end of the scale,<br />
and a wider range at the more degraded end. The reason for this is to expand the spread of expected<br />
water quality scores, and to ensure that a 10/10 score is truly representative of an exceptionally<br />
healthy waterway.<br />
The overall conclusion that can be drawn from the water quality scorecard is the fact that water<br />
quality appears to be naturally quite variable with time. There are a number of reasons for this<br />
variability, least of which is the influence of runoff from the surrounding catchment. While<br />
catchment runoff is inevitable and a natural response to rainfall on the watershed, the quantity and<br />
quality of the runoff have been modified by development and other activities within the catchment<br />
area. It is these anthropogenic factors that should be the focus of any water quality remediation<br />
programs for Brisbane <strong>Water</strong> and the <strong>Gosford</strong> coastal lagoons.<br />
3.2 <strong>Water</strong> <strong>Quality</strong> Datasondes<br />
<strong>Water</strong> quality datasondes (probes) have been installed at three locations in the <strong>Gosford</strong> <strong>Water</strong>s. One<br />
datasonde was located at Koolewong, in Brisbane <strong>Water</strong>, and the other two in Avoca Lagoon and<br />
Cockrone Lagoon. The datasondes were installed in March 1996, and have been collecting physical<br />
water quality parameter data every 15 minutes since that time.<br />
The results of the water quality datasondes are presented in Appendix A.<br />
3.2.1 Brisbane <strong>Water</strong> (Koolewong)<br />
Salinity was generally above 30ppt, and exhibited a behaviour whereby levels reduced suddenly (to<br />
generally between 20 and 30ppt) followed by a slow recovery up to approximately 35ppt (full<br />
oceanic salt concentrations). The sudden drops in salinity would correspond to catchment runoff<br />
events, while the recovery is the result of tidal flushing.<br />
Temperature showed a typical seasonal trend, with peak temperatures recorded in January / February<br />
(at levels of around 25 °C), and minimum temperatures recorded in July (at levels of around 13 °C).<br />
pH was generally between 7.5 and 8.5, although levels of up to 9 were recorded occasionally. There<br />
did not appear to be any correlation between pH and salinity, suggesting that pH was not strongly<br />
influenced by catchment runoff events. There was no distinguishable seasonal trend in pH levels<br />
either.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-15<br />
Table 3.23 <strong>Water</strong> <strong>Quality</strong> Index for <strong>Gosford</strong> <strong>Water</strong>s, 1999 - 2002<br />
Location 2001 / 2002 2000 / 2001 1999 / 2000<br />
Booker Bay 1.43 1.43 1.14<br />
Narara Ck entrance 1.71 1.86 1.57<br />
Erina Ck entrance 1.86 2.00 2.00<br />
Kincumber Ck entrance 2.14 1.71 1.57<br />
Cockle Broadwater 1.29 1.86 1.00<br />
Woy Woy Creek 1.71 2.43 1.86<br />
Wamberal Lagoon 1.57 2.00 1.57<br />
Terrigal Lagoon 1.43 2.14 1.86<br />
Avoca Lagoon 1.71 1.71 1.43<br />
Cockrone Lagoon 1.29 1.14 1.14<br />
Table 3.24<br />
Basic Scorecard Index<br />
1.00 – 1.09 10/10<br />
1.10 – 1.24 9/10<br />
1.25 – 1.49 8/10<br />
1.50 – 1.74 7/10<br />
1.75 – 1.99 6/10<br />
2.00 – 2.39 5/10<br />
2.40 – 2.79 4/10<br />
2.80 – 3.19 3/10<br />
3.20 – 3.59 2/10<br />
3.60 – 4.00 1/10<br />
Table 3.25 Scorecard for <strong>Gosford</strong> <strong>Water</strong>s, 1999 - 2002<br />
Location 2001 / 2002 2000 / 2001 1999 / 2000<br />
Booker Bay 8/10 8/10 9/10<br />
Narara Ck entrance 7/10 6/10 7/10<br />
Erina Ck entrance 6/10 6/10 6/10<br />
Kincumber Ck entrance 5/10 7/10 7/10<br />
Cockle Broadwater 8/10 6/10 10/10<br />
Woy Woy Creek 7/10 4/10 6/10<br />
Wamberal Lagoon 7/10 6/10 7/10<br />
Terrigal Lagoon 8/10 5/10 6/10<br />
Avoca Lagoon 7/10 7/10 8/10<br />
Cockrone Lagoon 8/10 9/10 9/10<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-16<br />
The dissolved oxygen concentrations measured by the probe are difficult to interpret and are of<br />
limited value. The reason for this is the fact that the probe appears to have been affected by<br />
biological fouling. The results show a slow decline in dissolved oxygen concentrations between<br />
changeover periods. At changeover, the levels increase suddenly, indicating that prior to changeover,<br />
recorded levels were incorrect.<br />
Turbidity levels measured at Koolewong were highly variable, with values up to 160 NTU recorded<br />
regularly. A comparison of the turbidity and salinity plots indicated that higher turbidity levels were<br />
not always corresponding to catchment runoff events (as depicted by a reduction in salinity levels).<br />
Therefore, other factors also affect turbidity levels at the Koolewong datasonde. By way of example,<br />
it may be possible that wind waves cause resuspension of finer bottom sediments in the vicinity of the<br />
Koolewong probe. Also, the turbidity probe appears to be affected by biological fouling, with sudden<br />
reductions in turbidity occurring at instrument changeover (and coinciding with sudden changes in<br />
dissolved oxygen levels).<br />
3.2.2 Avoca Lagoon<br />
The results of the Avoca Lagoon datasonde show that the Avoca Lagoon entrance broke out 14 times<br />
between March 1996 and June 2002. On most occasions tides returned to the lagoon following<br />
breakout for a period of a few days before closing once again. When closed, water levels in the<br />
lagoon respond to periods of catchment runoff (with sudden increases in water levels) and<br />
evaporation from the water surface (with slow reductions in water level).<br />
In most cases, salinity follows a reverse trend to water level, with dramatic increases in salt<br />
concentration associated with entrance breakout, followed by a gradual reduction in salinity as the<br />
lagoon hydrology is subsequently dominated by freshwater catchment inputs.<br />
Temperature showed a strong seasonal trend, with temperatures peaking in January / February at<br />
about 25 – 30 °C, and reaching a minimum in June / July at about 10 – 12 °C.<br />
pH varied considerably within Avoca Lagoon, between about 7 and 9.5, although some values greater<br />
than 10 were also recorded. In general, higher pH levels appeared to occur during the early summer<br />
months (Oct – Dec) with levels generally about 9 or greater. Levels would then reduce to about 7.5<br />
during late spring / winter months. It is suggested that the pH levels within Avoca Lagoon are<br />
influenced by the seasonal cycles of phytoplankton and macroalgae growth. Although chlorophyll-a<br />
monitoring has not been conducted to measure the amount of primary productivity within the lagoon,<br />
it is likely that the increasing temperatures associated with the early summer months would initiate<br />
higher amounts of productivity in the waterway, resulting in increasing pH levels. When pH levels<br />
are elevated, entrance breakout can also have an impact on pH, as most of the phytoplankton and<br />
macroalgae would be removed or detrimentally affected by the sudden change in lagoon hydrology.<br />
Dissolved oxygen levels in Avoca Lagoon vary between 16 mg/L and zero. Oxygen levels can be<br />
influenced by several different factors in mostly closed lagoons, including phytoplankton and<br />
macroalgae growth (photosynthesis), organic decay (respiration), entrance breakout, and catchment<br />
runoff. The DO probe also shows some signs of biological fouling of the sensor, so all information<br />
derived from the data should be used with caution.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-17<br />
Turbidity in Avoca Lagoon is also highly variable, with measurements up to 160 NTU. As discussed<br />
for the Koolewong site, turbidity records can be influenced by fouling of the probe, and there appears<br />
to be some evidence of this at Avoca Lagoon. Also, given its relatively shallow water, stirring of fine<br />
bed sediments during periods of lower water levels would also be a notable cause of elevated<br />
turbidity levels in Avoca Lagoon. Higher turbidity concentrations are observed during and flowing<br />
entrance breakout events, and also periods of catchment runoff (which do not result in entrance<br />
breakout).<br />
3.2.3 Cockrone Lagoon<br />
The Cockrone Lagoon entrance also broke out 14 times during the period March 1996 to Jun 2002,<br />
which included a period of 20 months (Sept 1999 to May 2001) when no breakouts occurred. The<br />
hydrology of Cockrone Lagoon is very similar to that described for Avoca Lagoon, with sudden<br />
responses to catchment runoff, gradual evaporation effects, and small periods of tidal influence<br />
following entrance breakout.<br />
The salinity of Cockrone Lagoon is variable, falling to levels of about 6ppt when the lagoon is ‘full’,<br />
and peaking at levels well in excess of oceanic salt concentrations (i.e. Hypersaline conditions)<br />
following breakout, recharge with ocean waters, and subsequent evaporation of ocean waters from the<br />
closed waterway.<br />
Temperature within Cockrone Lagoon varied on a seasonal basis, from approximately 25 – 30 °C in<br />
the summer to about 10 – 15 °C in the winter.<br />
pH levels generally ranged between 7 and 10. Similar to Avoca Lagoon, the pH levels in Cockrone<br />
Lagoon generally followed a seasonal trend, with higher levels during the later Autumn / early<br />
Summer months, and lower levels during the Autumn / Winter months. This trend was somewhat<br />
disrupted by the predominantly dry period of 2000 / 2001, which resulted in higher than expected pH<br />
levels for the majority of the time. pH is likely to be affected by the amount of primary productivity<br />
(photosynthesis) occurring within the water.<br />
Dissolved Oxygen (DO) in Cockrone Lagoon is highly variable ranging between 16 mg/L and zero.<br />
Although not completely evident, there appears to be a trend in DO concentrations that is also<br />
seasonal. Higher DO concentrations are recorded during the late autumn / early summer period,<br />
coinciding with the increase in primary productivity (as suggested by the higher pH levels). Lower<br />
DO levels occur during mid to late summer, extending through autumn. It is possible that the higher<br />
primary production rates in early summer are unsustainable, resulting in a massive die-off of the algae<br />
colonies. The decay (reduction) of this organic matter would generate a significant oxygen demand<br />
on the water column, thus depleting DO levels.<br />
Turbidity in Cockrone Lagoon is mostly less than about 10 NTU, however, some periods of heighten<br />
hydrologic activity result in significantly elevated turbidity levels (up to 160 NTU). Higher turbidity<br />
is recorded coinciding with catchment runoff events and entrance breakouts. However, there remains<br />
a considerable amount of data with higher turbidity concentrations that cannot be explained by such<br />
mass hydrologic processes.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-18<br />
3.3 <strong>Historical</strong> <strong>Water</strong> <strong>Quality</strong> Results<br />
3.3.1 Chemical Parameters<br />
Chemical parameters, such as nitrogen and phosphorus have been measured within the <strong>Gosford</strong><br />
waters at various times in the past. John Laxton (1994, 1999) completed two different monitoring<br />
programs in the 1990s, with monitoring carried out approximately monthly. The first period was<br />
from September 1993 to October 1994. The second period was from February 1996 to December<br />
1998. Monitoring sites for these previous programs were not the same as the most recent monitoring<br />
program by Cheng, and therefore, direct comparisons between the datasets is difficult.<br />
A summary of the water quality results for the coastal lagoons, taken from the previous Laxton<br />
datasets, is provided in Table 3.26. The most recent Cheng data is also shown in this table for<br />
comparative purposes.<br />
As can be seen in Table 3.26, the total nitrogen concentrations measured by Laxton are considerably<br />
lower than those taken by Cheng. There are a number of possible explanations for this significant<br />
different in results, including monitoring at different sites, and the use of different analytical<br />
approaches (both Laxton and Cheng use non-NATA accredited labs when determining water quality).<br />
Table 3.26 Nutrients in the Coastal Lagoons (1993 – 2002)<br />
1993/94 Mean 1996 – 98 Mean 1999 – 2002 Mean (Cheng)<br />
Total Nitrogen (mg/L)<br />
Wamberal Lagoon 0.65 0.60 2.51<br />
Terrigal Lagoon 0.72 0.52 2.48<br />
Avoca Lagoon 0.80 0.70 1.60<br />
Cockrone Lagoon 1.23 0.85 1.72<br />
Total Phosphorus (mg/L)<br />
Wamberal Lagoon 0.058 0.060 0.062<br />
Terrigal Lagoon 0.064 0.059 0.082<br />
Avoca Lagoon 0.079 0.066 0.070<br />
Cockrone Lagoon 0.052 0.054 0.046<br />
The total phosphorus concentrations were more similar between the Laxton and Cheng results. This<br />
may indicate that similar analytical techniques were adopted for both monitoring programs.<br />
Cheng also carried out a limited water quality monitoring program in Brisbane <strong>Water</strong> between April<br />
1993 and April 1994. <strong>Water</strong> quality at sites within Brisbane <strong>Water</strong> showed reasonably consistent<br />
results during this period, with a typical mean Total Phosphorus concentration of about 0.075 mg/L<br />
and a typical mean Total Inorganic Nitrogen concentration of about 0.135 mg/L. Cheng also noted<br />
that concentrations of phosphorus and inorganic nitrogen increased substantially following rainfall.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-19<br />
3.3.2 Bacteria<br />
Faecal coliforms, and to a lesser extent Total Coliforms, have been monitored in the <strong>Gosford</strong> waters<br />
as part of past water quality monitoring programs. Laxton has primarily been responsible for<br />
monitoring of bacteria at <strong>Gosford</strong> as part of environment monitoring programs. Bacterial results from<br />
Laxton’s 1996 – 1998 monitoring program are presented in Table 3.27. This table shows that the<br />
coastal lagoons and the tributary creeks are most susceptible to bacterial contamination, while sites<br />
within the broader Brisbane <strong>Water</strong> estuary are least affected by bacteria.<br />
Bacteria is also measured by <strong>Council</strong> as part of their routine Public Health Monitoring Program.<br />
Bacteria in the vicinity of the oyster leases within Brisbane <strong>Water</strong> are further monitoring under the<br />
Shellfish <strong>Quality</strong> Assurance Program (SQAP).<br />
Table 3.27 Faecal Coliform Levels (no. per 100mL) 1996 – 1998 (from Laxton, 1999)<br />
Location Median (50%ile) Mean Maximum<br />
Wamberal Lagoon 22 319 7500<br />
Terrigal Lagoon 114 341 2500<br />
Avoca Lagoon 19 173 2250<br />
Cockrone Lagoon 31 172 2000<br />
Narara Creek 95 669 10000<br />
Erina Creek 132 507 5000<br />
Kincumber Creek 410 2671 20000<br />
Cockle Broadwater 8 112 1000<br />
Koolewong 3 20 355<br />
Woy Woy 6 29 300<br />
Booker Bay 16 43 250<br />
3.3.3 Algae<br />
3.3.3.1 Algal counts<br />
Biological monitoring of Brisbane <strong>Water</strong> and the coastal lagoons was carried out by Cheng between<br />
August 1999 and June 2002 (Ecoscience Technology, 2002). Algal cell count results for the later half<br />
of this monitoring period (i.e. Oct 2000 – June 2002) are summarised in Table 3.28.<br />
Table 3.28 Algal cell count results 2000 – 2002 (Ecoscience Technology, 2002)<br />
Location Minimum Maximum %age over 1000 cells/ml<br />
Narara Ck 7 475 0<br />
Erina Ck 6 1021 2<br />
Kincumber Ck 6 13634 40<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-20<br />
Cockle Ck 9 212 0<br />
Woy Woy Ck 9 10760 29<br />
Brisbane <strong>Water</strong> 9 4532 9<br />
Booker Bay 7 6055 7<br />
Wamberal Lagoon 14 803 0<br />
Terrigal Lagoon 11 320 0<br />
Avoca Lagoon 7 1679 2<br />
Cockrone Lagoon 12 500000+ 9<br />
Of particular interest are the results for Cockrone Lagoon. As reported in Ecoscience Technology<br />
(2002), Cockrone Lagoon was opened and drained in February 2002 (refer Appendix A for MHL<br />
gauging of water levels in Cockrone Lagoon). Following drainage of the lagoon, filamentous bluegreen<br />
alga Oscillatoria (and other related species) grew rapidly on the exposed lagoon sediments.<br />
The algae remained in high numbers for a week or so until the water level increased following heavy<br />
rainfall. Comparisons with the MHL data indicate that dissolved oxygen in the lagoon (or at least at<br />
the datasonde location) was very low during the algal bloom (< 2 mg/L), while turbidity levels were<br />
high (up to 160 NTU), due to the fragmentation and resuspension of the benthic algae into the water<br />
column.<br />
Cheng indicates that the entrance openings of the coastal lagoons seem to cause a number of<br />
ecological problems, such as massive algal growth (and reduced dissolved oxygen levels), and that<br />
the lagoons need to be actively management and monitored to prevent degradation. In particular,<br />
Cheng points to better management of entrance openings, to be more sympathetic to lagoon ecology,<br />
as a means of minimising future degradation of the coastal lagoons.<br />
Further details on biological monitoring of the <strong>Gosford</strong> <strong>Water</strong>s are available in Ecoscience<br />
Technology (2000, 2002).<br />
3.3.3.2 Chlorophyll-a<br />
Chlorophyll-a can be considered as an indicator of algal growth, as it is a measure of the amount of<br />
green pigment within the water. Recent research by the University of Newcastle suggests that<br />
chlorophyll-a is a good surrogate of the amount of primary productivity within an estuarine waterway<br />
(pers comm. Dr A Redden, Uni. of Newcastle).<br />
Chlorophyll-a has been monitored within the <strong>Gosford</strong> waters as part of Laxton’s previous water<br />
quality monitoring programs (1993/94, 1996 – 1998). A summary of Laxton’s chlorophyll-a results<br />
for the latter of these two programs is shown in Table 3.29.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
RESULTS OF WATER QUALITY DATA ANALYSIS 3-21<br />
Table 3.29 Chlorophyll-a results (µg/L) 1996 – 1998 (Laxton, 1999)<br />
Location Median (50%ile) Mean Maximum<br />
Wamberal Lagoon 3.8 5.1 21.4<br />
Terrigal Lagoon 4.6 5.2 13.6<br />
Avoca Lagoon 4.2 5.0 19.6<br />
Cockrone Lagoon 6.2 14.3 193.5<br />
Narara Creek 3.9 5.0 29.0<br />
Erina Creek 4.1 5.4 20.0<br />
Kincumber Creek 8.5 12.1 65.9<br />
Cockle Broadwater 2.3 2.5 5.2<br />
Koolewong 2.7 2.7 5.7<br />
Woy Woy 1.9 2.4 6.1<br />
Booker Bay 2.5 3.0 8.9<br />
Once again Cockrone Lagoon showed a period of excessive algal growth, as indicated by the very<br />
high chlorophyll-a recording (193.5 µg/L on 1 July 1997). A closer examination of this event has<br />
revealed that the high levels were recorded the day before the entrance broke out. Thus, the algae<br />
bloom was not the result of an entrance breakout as was the case in February 2002 (as described in<br />
Section 3.3.3.1 above).<br />
Overall, Cockrone Lagoon had relatively high levels of chlorophyll-a. Likewise, Kincumber Creek<br />
also had high levels of chlorophyll-a, although the amount of chlorophyll-a in all of the coastal<br />
lagoons and the tributary creeks was higher than what would be expected under more natural<br />
conditions. Typical chlorophyll-a concentrations in the broader, more flushed, sections of Brisbane<br />
<strong>Water</strong>, were generally lower than the lagoons and tributary sites.<br />
3.3.4 Metals<br />
Very little water quality data regarding soluble metals is available. The only information in the<br />
database is from 1974, when concentrations of some basic metals (Calcium, Copper, Lead, Mercury,<br />
Zinc) were measured at a number of locations in the four coastal lagoons by R.A. Creelman, as noted<br />
in the <strong>Gosford</strong> Coastal Lagoons Estuary Processes Study (Webb McKeown & Associates, 1995).<br />
The results of the monitoring generally indicated low metal concentrations (mostly below the<br />
detection limits for the analysis).<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-1<br />
4 FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL<br />
HEALTH MONITORING<br />
4.1 Discussion of Previous Monitoring Programs<br />
<strong>Water</strong> quality has been collected within <strong>Gosford</strong> <strong>City</strong> <strong>Council</strong>’s waterways since 1974. The most<br />
recent monitoring program was carried out by Dominic Cheng of Ecoscience Technology, and<br />
concluded in June 2002 (following nearly 3 years of data collection at 10 sites within Brisbane <strong>Water</strong><br />
and the coastal lagoons).<br />
In total, water quality data has been collected from over 200 different sites within the <strong>Gosford</strong><br />
waterways, with over 60 different parameters monitored. Generally, it can be said that water quality<br />
monitoring in the past has not been carried out in a consistent or integrated manner. New programs<br />
have generally targeted new sites and sometimes new parameters. Programs have also been carried<br />
out for specific purposes, such as the water quality monitoring of the tributary creeks (AWT, 2001)<br />
and the periodic algae monitoring (Ecoscience Technology, 2000, 2002).<br />
The result of the generally uncoordinated and inconsistent monitoring programs of the past is the fact<br />
that the data provides little opportunity for interpretation of long-term trends and spatial distribution<br />
patterns. At best the data provides a ‘snap shot’ of conditions at a particular place and time. This<br />
conclusion is supported by Umwelt and SMEC (2002) as part of the Brisbane <strong>Water</strong> Data<br />
Compilation Study.<br />
4.2 The Notion of ‘Environmental Health’<br />
The term ‘environmental health’, or sometimes more specifically ‘ecosystem health’, has been used<br />
for at least the last 10 years. The idea of quantifying the health of the environment has great appeal to<br />
managers, as it can provide an indication of how a system is improving, or degrading. Quantification<br />
of environmental health can help prioritise works for rehabilitation, and can provide a measure of the<br />
effectiveness of the works, once implemented.<br />
While the notion of environmental health is attractive to managers, it proves to be problematic for<br />
scientists. Coates at al (2002) points out the difficulties in defining ecosystem health given the large<br />
variability that natural ecosystems experience (as highlighted by the data presented in this document).<br />
He also highlights the difficulties in selecting an appropriate range of biotic and abiotic indicators to<br />
represent the ecosystem. It is generally agreed that an ecosystem measure based on single indicators<br />
is unreliable and possibly unrepresentative.<br />
4.2.1 Coastal CRC EHMP<br />
The most comprehensive environmental health assessment currently underway is likely to be that by<br />
the CRC for Coastal Zone, Estuary and <strong>Water</strong>way Management (Coastal CRC) in South – East<br />
Queensland. The CRC’s Ecosystem Health Monitoring Program (EHMP) monitors estuarine<br />
waterways to determine if:<br />
• Key environmental processes operate to maintain stable ecosystems<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-2<br />
• Human impacted zones do not deteriorate further<br />
• Critical habitats such as seagrass beds do not deteriorate.<br />
The CRC EHMP is based on a conceptual model of ecosystem processes. The model focuses on<br />
assessing the responses of the ecosystem to natural and human impacts, as shown in the figure below.<br />
The EHMP uses a range of biological indicators and water quality parameters to assess the<br />
ecosystem, and gauge the effectiveness of management practices being implemented within the<br />
catchments and around the foreshores.<br />
Figure 4.1 Conceptual model of the current ecosystem health of Moreton Bay and its<br />
river estuaries (Coastal CRC)<br />
Information collected by the CRC that contributes to the assessment of ecosystem health includes:<br />
• water quality<br />
• extent of sewage plumes<br />
• seagrass loss and recovery<br />
• toxic algal blooms<br />
• occurrence of nuisance algae<br />
• phytoplankton growth responses<br />
• turtle and dugong populations<br />
A few of these are described further below.<br />
4.2.1.1 <strong>Water</strong> quality<br />
<strong>Water</strong> quality monitoring is carried out monthly, and includes physical and chemical parameters.<br />
Physical indicators comprise Dissolved Oxygen, Turbidity, Salinity, Temperature and pH, while<br />
chemical indicators include Total Nitrogen; Ammonia; Oxides of Nitrogen; Total Phosphorus,<br />
Filterable Reactive Phosphorus; and chlorophyll-a.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-3<br />
4.2.1.2 Seagrass<br />
The depth range of the seagrass Zostera capricorni is monitored twice yearly at 18 locations<br />
throughout Moreton Bay. In the bay, the depth at which this seagrass can grow depends on water<br />
quality, particularly light availability (refer Figure 4.2). Detection of changes to the seagrass depth<br />
range therefore provides an indication of long term integrated water quality throughout the bay and if<br />
it is impacting on the integrity of these critical habitats.<br />
Figure 4.2 Seagrass depth range measures the distance between the upper tidal<br />
limit of seagrass distribution and the lower light-limited distribution<br />
4.2.1.3 Sewage<br />
Sewage effluent can contribute to the eutrophication of receiving estuarine and coastal waterways. It<br />
is important to be able to trace the source and extent of sewage effluent in receiving waters in order to<br />
evaluate the extent of its impact on the ecosystem. The use of nitrogen stable isotopes enables the<br />
detection and delineation of sewage-derived nitrogen from other nitrogen sources entering the<br />
waterways and its potential influence on the ecosystem. The most abundant form of naturally<br />
occurring nitrogen is 14 N. Sewage is generally enriched in 15 N compared to 14 N and therefore the<br />
relative proportion of 15 N to 14 N, referred to as d 15 N, is elevated in receiving waters of sewage<br />
treatment plants.<br />
4.2.1.4 Report cards<br />
Report cards are provided annually outlining the overall condition of the South-East Queensland<br />
waterways, based on the EHMP results. An example of an EHMP report card is provided in Figure<br />
4.3, while an example plot of the spatial representation of the Ecosystem Health Index is presented in<br />
Figure 4.4.<br />
The report cards provide a clear picture of the overall health of the waterways, and more importantly,<br />
how they relate to previous years. By comparing the waterway health with past results, managers and<br />
decision-makers can obtain quantitative feedback on the relative success of various management<br />
measures implemented within the catchments. The report cards are released each year amid the<br />
Annual Riverfestival, which is designed to maximise community awareness and ownership of the<br />
waterways and their issues.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-4<br />
Figure 4.3 Example of EHMP Report Card<br />
Figure 4.4 Spatial Distribution of Ecosystem Health Index values in Moreton Bay<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-5<br />
4.3 <strong>Review</strong> of ANZECC Monitoring Guidelines<br />
4.3.1 Introduction<br />
The following sections are essentially a summary of the <strong>Water</strong> <strong>Quality</strong> Monitoring approach outlined<br />
in the joint Australian and New Zealand Environment Conservation <strong>Council</strong> (ANZECC) and<br />
Agriculture and Resource Management <strong>Council</strong> of Australia and New Zealand (ARMCANZ)<br />
guideline document Australian Guidelines for <strong>Water</strong> <strong>Quality</strong> Monitoring and Reporting.<br />
4.3.2 Setting Objectives<br />
The first step in undertaking any water quality monitoring exercise is to set clear objectives.<br />
Objectives are recommended to be set utilising the process outlined in Figure 4.5.<br />
Figure 4.5 Framework for Setting Objectives (ANZECC/ARMCANZ, 2000)<br />
The first step in the process is to define the issue that has resulted in planning of the monitoring<br />
program. The issues in Australia generally fall into one of four categories-:<br />
• long term management, protection and restoration of aquatic ecosystems so they can fulfil their<br />
environmental values;<br />
• contaminants, their sources and fates in aquatic ecosystems, the magnitude of the problem and<br />
actions required to protect the environmental values;<br />
• performance of management strategies;<br />
• conformity with water quality guidelines.<br />
The information requirements are defined from discussions with the stakeholders of the water body of<br />
interest, or whom are involved in the monitoring programme. The information requirements<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-6<br />
essentially enable identification of issues that the stakeholders need addressed to narrow down the<br />
scope for the monitoring programme.<br />
The information requirements are then used as a base to compile and review relevant data. The<br />
information may be gathered from sources including previous monitoring, literature reviews, and<br />
community consultation. Data gaps should be identified at this stage and attempts made to fill these<br />
gaps and/or assess the limitations of not having the information.<br />
A conceptual process model is then developed to identify the key processes in the system that require<br />
monitoring. The conceptual process model outlines the understanding of how the system functions,<br />
and what are considered to be the dominant processes. The model only needs to be a simple box<br />
diagram that shows components and linkage in the system to be monitored. During the formulation<br />
of the model, a number of key decision need to be made to limit the complexity of the model. These<br />
include-:<br />
• What is the issue? (e.g. nutrients, metals).<br />
• What subsystem should the model describe? (e.g. freshwater, marine, wetland, mangroves).<br />
• What state of flow should the model describe? (e.g. base flow, flood).<br />
The key processes that define the ‘cause and effect’ and ‘how the system works’ need to be defined.<br />
The key processes that affect water quality include-:<br />
• transport, flow, turbulence, flushing, mixing and stratification;<br />
• precipitation, evaporation, wet and dry deposition;<br />
• contaminant transport, sedimentation, burial, resuspension and diffusion;<br />
• contaminant transformation, degradation, adsorption, desorption, precipitation, dissolution;<br />
• sulfate reduction, methanogenesis, organic diagenesis;<br />
• bioturbation, bioirrigation;<br />
• organism growth, primary productivity, grazing, succession; and<br />
• nutrient recycling, loss, transformation, recycling, ammonification, nitrification, denitrification.<br />
Following development of a conceptual process model, the understanding of information required to<br />
be collected is more clear, and the objectives for the monitoring programme can be defined. The<br />
objectives need to be specific, measurable, result orientated, realistic, and concise. Examples of<br />
typical objectives include-:<br />
• to determine annual nutrient loads from a specific catchment in a specific system;<br />
• to determine if specific contaminant concentrations from urban development exceed ANZECC<br />
water quality guideline trigger values for the protection of aquatic ecosystems in the receiving<br />
waters beyond the mixing zone.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-7<br />
4.3.3 Study Design<br />
The study design outlines a set of steps to take to ensure that a sampling and analysis program is cost<br />
effective. The study design also specifies the data requirements. The study design process is outlined<br />
in Figure 4.6.<br />
Figure 4.6 Framework for Study Design (ANZECC/ARMCANZ, 2000)<br />
Initially the study type needs to be defined. There are three distinct study types:<br />
• descriptive studies (e.g. monitoring for testing against water quality guidelines);<br />
• change measuring studies (e.g. studies repeated at the same location before and after a change);<br />
• studies that improve system understanding (e.g. study to understand biological processes in a<br />
particular aquatic ecosystem).<br />
The study scope is then set to define-:<br />
• specific geographic boundaries (e.g. will the study monitor tributaries of a major river, or just the<br />
major river);<br />
• scale of monitoring to suit the phenomenon being monitored (both on spatial and temporal<br />
scales);<br />
• study duration ( to satisfy the requirement to better understand the system).<br />
The sampling design is then undertaken considering a number of issues including-:<br />
• variability – spatial, temporal, seasonal, contaminant loads, land uses;<br />
• sampling locations – number required, safe access, easily located, minimise intervention of<br />
humans (i.e. away from bridges), appropriate spacing of sites;<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-8<br />
• sampling frequency – dictated by objectives and characteristics of the parameter being measured;<br />
• sampling numbers and precision – selected to detect changes, differences or effects based on the<br />
parameter being measured;<br />
• selection of measurement parameter – linked to the objective of the study and typically depends<br />
on the environmental values of the water body. The parameters used to assess the water quality<br />
can be either physical, chemical or biological;<br />
• cost effectiveness – requires optimisation of the cost of the data acquisition with the statistical<br />
power of the gathered data.<br />
4.3.4 Field Sampling Program<br />
The field sampling program identifies what the specific data requirements are, and outlines whether<br />
the parameters are to be measured in the field or in the laboratory. Planning is required to ensure that<br />
the sampling falls within the budget, without compromising to a detrimental extent on the statistical<br />
power of the findings. The field sampling program also outlines the protocol to be followed in<br />
sample collection, preservation, storage and transportation. The considerations for the field sampling<br />
program are outlined in Figure 4.7.<br />
Figure 4.7 Framework for Field Sampling Program (ANZECC/ARMCANZ, 2000)<br />
The specific data requirements for the field sampling program are determined during the sampling<br />
design phase.<br />
The sample collection methods are determined based on the parameters identified during the<br />
sampling design. The methods include hand sampling, autosampling, integrated sampling, real time<br />
sampling (automated), field measurements, remote sensing and field observation. The equipment<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-9<br />
used for sampling of surface waters include bottle samplers, pumping systems, depth samplers,<br />
automatic samplers and integrated samplers. Groundwater sampling utilisers a number of pumping<br />
methods. Sediments are often sampled to determine the composition and concentration of<br />
contaminants, as well as the number of organisms. Sediments are typically sampled using a range of<br />
dredge, grab and coring methods. The choice of sampling method will depend on the parameter and<br />
conditions being measured. All methods and equipments are required to meet relevant Australian or<br />
ISO standards.<br />
A number of parameters can only be accurately measured in the field (eg temperature, flow), whilst<br />
others are susceptible to change in the sample after collection (eg dissolved oxygen, pH).<br />
Consideration should be given at this stage to utilising highly reliable sensors that are capable of<br />
accurately recording these types of parameters in the field.<br />
The sample containers are selected to minimise the potential for adsorption or contamination of the<br />
sample. Glass and plastic containers each have potential limitations and methods to consider for<br />
preparing the containers for sampling.<br />
Particular care is required with sampling protocols to prevent contamination of the samples by dust,<br />
powder, skin and hair. Care is particularly required when boats and helicopters are used to assist with<br />
sampling to ensure that these forms of transport do not lead to contamination of the samples.<br />
Observations and characteristics of the site should also be recorded at the time of sampling, and<br />
recorded on a standardised field sheet. A quality assurance/control system is required for field<br />
sampling to control sampling errors and manage the samples following collection. Field staff will<br />
need to be trained and be competent at undertaking the sampling tasks. The hazards likely to be<br />
encountered by the sampling staff will need to be identified and addressed to ensure that these<br />
hazards are minimised.<br />
4.3.5 Laboratory <strong>Analysis</strong><br />
The objective of the laboratory analysis is to obtain accurate and precise data in a safe environment.<br />
The recommended methodology for laboratory analysis is summarised in Figure 4.8.<br />
Figure 4.8 Framework for Laboratory <strong>Analysis</strong> (ANZECC/ARMCANZ, 2000)<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-10<br />
The selection of appropriate methods for analysing the physical, chemical or biological analytes will<br />
be dependent on the objectives of the monitoring programme, available budget, laboratory resources,<br />
speed on analysis, matrix type and contamination potential. The choice of an appropriate method is<br />
based on four primary considerations-:<br />
• The range of concentrations of the analytes that need to be detected (detection limits are method<br />
specific);<br />
• The accuracy and precision required (all results are only estimates, higher accuracy and precision<br />
increases the costs);<br />
• The period between sampling and analysis (some analysis may be required on-site); and<br />
• Familiarity with a particular method when more than one suitable method is available.<br />
Laboratory analyses also need to consider a range of issues including-:<br />
• Data management ( data storage and reporting);<br />
• <strong>Quality</strong> assurance/control; and<br />
• OH&S ( identification of hazards, risk minimisation plans, education).<br />
4.3.6 Data <strong>Analysis</strong> and interpretation<br />
A number of common statistical methods are used for the analysis of water quality data. A<br />
methodology for undertaking data analysis is shown in Figure 4.9.<br />
Figure 4.9 Framework for Data <strong>Analysis</strong> (ANZECC/ARMCANZ, 2000)<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-11<br />
The data initially needs to be summarised from the laboratory into a form that is suitable for analysis,<br />
and preliminary checks made for erroneous, missing or below detection data. Suitable approaches for<br />
dealing with these types of data will need to be considered.<br />
The checked data is then reduced and summarised using a combination of commonly used statistical<br />
tools, including graphs, tables, statistical measures (e.g. mean, standard deviation). The objective of<br />
the summarised data is to present essential information contained in the data set concisely, and to<br />
assist in clearly identifying outliers. Advances in computer software have enabled highly<br />
sophisticated graphics to be readily accessible.<br />
A number of more advanced statistical methods are then typically used to assess data relationships.<br />
Methods including transformations, checking distributional assumptions, trend detection and<br />
smoothing can be undertaken.<br />
It is then important to subject the data to a process of statistical inference to assist with determining<br />
characteristics of the data set, enabling testing of hypothesis and comparison of the data with water<br />
quality guideline or trigger values.<br />
The relationship between pairs of water quality variables can be evaluated using correlation and<br />
regression analysis.<br />
Following the data analysis, the results should be summarised concisely, and compared with the<br />
monitoring programme objectives to determine if the original questions are answered by the results.<br />
4.3.7 Reporting<br />
The reporting of data from the water quality monitoring requires careful consideration of the end user<br />
to ensure that the technical nature of the topic is presented to the intended audience in an appropriate<br />
format.<br />
• Executive summary – summarises technical findings for managers;<br />
• Introduction – Outlining study objectives, study location and review of previous/related studies;<br />
• Methodology – Outline of study design, sampling and analysis methods;<br />
• Results – Summarised results;<br />
• Discussion – Data interpretation and implications for management;<br />
• Conclusions<br />
• Recommendations<br />
• References<br />
• Appendices – laboratory reports, data tables<br />
The report findings can be disseminated in a number of ways depending on the intended audience.<br />
Methods for disseminating the data include publications, meetings, internet web pages, film and<br />
video presentations, and media reporting.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-12<br />
4.4 Outcomes from Community Workshops<br />
A series of workshops were held (on 23 June 2003) with the <strong>Gosford</strong> community to discuss the future<br />
directions for <strong>Council</strong>-operated water quality monitoring of Brisbane <strong>Water</strong> and the coastal lagoons.<br />
Presented below is a summary of the key issues raised by community members during these<br />
workshops.<br />
4.4.1 General Comments<br />
The following general comments were made by the community:<br />
• Want water to be safe to swim in and safe for aquatic life, including coastal lagoons<br />
• Better integration of monitoring by CCCEN, <strong>Water</strong>watch and oyster farms, as well as <strong>Council</strong><br />
monitoring, is required<br />
• Need to use the data once it is collected<br />
• Is there a need for more extensive biomonitoring, including pests?<br />
• <strong>Water</strong> quality in coastal lagoons needs to be considered in light of their hydrologic cycles<br />
• <strong>Water</strong> quality of coastal lagoons is different from Brisbane <strong>Water</strong>s<br />
• Need to monitor for environmental health<br />
• Can’t rely on tidal flushing to keep water quality good, therefore need to focus on remediation of<br />
catchment activities<br />
• Hawkesbury catchment has generally been overlooked in the past<br />
4.4.2 Possible Sites for Future Monitoring<br />
The following locations were suggested by the community members, as possible sites for future<br />
monitoring;<br />
• Green Point Creek, Pearl Beach<br />
• Siltation at Killcare and Hardys Bay<br />
• More offshore sites needed to provide picture of broader waterway<br />
• Erina Creek, particularly given all the development<br />
• GPTs<br />
• Target worst sites from past data, including industrial areas<br />
• Top of the catchment<br />
• Wamberal Lagoon – housing development upstream<br />
• Stormwater outfall and at marinas<br />
• Areas of landfill<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-13<br />
4.4.3 Possible Parameters for Future Monitoring<br />
The following comments regarding what to monitor, were made by community members:<br />
• More public health parameters<br />
• Turbidity, particularly in the Hawkesbury catchment<br />
• Different sites may require different tests<br />
• Biological parameters, eg plankton<br />
• Chemical parameters<br />
• Physical parameters<br />
• Bacterial parameters, eg E. coli in areas of septic tank usage<br />
• Flow, eg in Erina Creek<br />
• Urban contaminants, as measured in GPTs<br />
4.4.4 Possible Frequency of Monitoring<br />
The community provided the following comments regarding when to monitor in the future:<br />
• Monitor storm events, using automatic samplers<br />
• Pre-development to get baseline conditions<br />
4.4.5 Possible Ways of Reporting the Data<br />
The community expressed a number of concerns regarding dissemination of the data collected. The<br />
following are comments provided by the community in this regard:<br />
• Information needs to be reported back to people doing the monitoring (<strong>Water</strong>watch specifically)<br />
and a formal network is needed<br />
• Need a common database for all water quality data and a website to access the data<br />
• Establish an e-mail forum<br />
• State of Environment reports, with specific community profiles and feedback on success of what<br />
has been done<br />
• Once a year formally, with quarterly updates on website and in local paper, and possibly rates<br />
notices<br />
• Star rating is a concern as it is subjective<br />
• Need to see actual data on website if want to<br />
• Differentiate community feedback based on regional locality and relevance to waterways (eg.<br />
Woy Woy residents not interested in coastal lagoons data)<br />
• Use the media wherever possible and maximise education opportunities<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-14<br />
4.5 Options for Future <strong>Water</strong> <strong>Quality</strong> Monitoring<br />
A range of options for the future water quality / environmental health monitoring of <strong>Gosford</strong> waters<br />
have been considered. The options have been developed in light of <strong>Council</strong>’s expected financial<br />
restrictions (i.e. currently in the order of $40,000 per annum and possibly increasing to $50,000 -<br />
$60,000 in the future).<br />
Four different options have been formulated, targeting different aspects of the water environment.<br />
Therefore, the options can be adopted individually or in combination, in order to achieve <strong>Council</strong>’s<br />
objectives regarding future water quality / environmental health monitoring. The options are<br />
discussed in detail below.<br />
4.5.1 Option 1: Routine Monthly <strong>Water</strong> <strong>Quality</strong> Monitoring<br />
This option involves continuing the basic program of monitoring that was being carried out by Cheng<br />
(on behalf of <strong>Council</strong>) prior to July 2002. It would involve a minimum of 10 sites around the coastal<br />
lagoons and within Brisbane <strong>Water</strong>, and would be monitored on a regular monthly basis.<br />
In-situ water quality would be measured by hand-held probe at the time of sampling. The probe<br />
would measure pH, dissolved oxygen, salinity, temperature and turbidity. Collected water samples<br />
would be tested for BOD, ammonia, oxidised nitrogen, TKN, total nitrogen, orthophosphate, total<br />
phosphorus, suspended solids, chlorophyll-a and enterococci. In addition, it is suggested that three<br />
sites also be analysed for algal counts and composition. Experimental data from the University of<br />
Newcastle suggests that chlorophyll-a concentrations is a good surrogate for primary productivity (i.e.<br />
algae) within the water column. Therefore, monitoring chlorophyll-a at all sites provide an indication<br />
of primary productivity, while concurrent monitoring of algal counts and composition at three sites<br />
will provide additional data for identifying correlations between chlorophyll-a and primary<br />
production.<br />
The sites would include, as a minimum, Wamberal Lagoon, Terrigal Lagoon, Avoca Lagoon,<br />
Cockrone Lagoon, Woy Woy Creek, Narara Creek, Erina Creek, Kincumber Creek, Cockle Creek,<br />
and Booker Bay. The sites for the additional algae monitoring would likely include two coastal<br />
lagoons (one being Cockrone Lagoon) and one site in Brisbane <strong>Water</strong>. Further consideration to the<br />
locations of sampling should be given in light of the SQAP monitoring being carried out within<br />
Brisbane <strong>Water</strong>, and the CCCEN Streamwatch monitoring sites within the catchment.<br />
Although it is not intended to target public health, we consider that monitoring a relatively longlasting<br />
bacteria, such as enterococci, would provide a sound basic indicator for sewage inputs to the<br />
waterway associated with overflows and general urban runoff. An alternative to bacteria is faecal<br />
sterols. These compounds, found in the gut of animals (including humans) are a very good indicator<br />
of faecal contamination, as they do not readily break down in the natural environment. Also,<br />
composition of the sterols allows us to identify the source of the contaminant (eg humans, other<br />
omnivores, herbivores, etc). Another alternative, which is used as part of the South-East Queensland<br />
EHMP (refer Section 4.2.1) is d 15 N (delta 15 nitrogen). This is the difference between the 15 N and<br />
14 N isotopes, with 15 N generally associated with sewage discharges. Unfortunately, delta-N and<br />
faecal sterols assessments are both quite expensive at present, although it is understood that the<br />
University of Newcastle has recently developed techniques for rapid assessment of faecal sterols<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-15<br />
using mass spectrometers, and is carrying out regular analysis for Lake Macquarie <strong>City</strong> <strong>Council</strong> (pers.<br />
comm. Assoc. Prof. Hugh Dunstan, Uni of Newcastle).<br />
To maximise the value of the water quality data, it is suggested that a few other environmental<br />
parameters be collected at the time of sampling. This would include the water level, and antecedent<br />
rainfall. For the coastal lagoons, it is suggested that tideboards are installed at the water quality<br />
monitoring sites, so that water levels can be easily read and documented at the time of sampling.<br />
Also, it should be noted whether the entrance of each lagoon is open or closed. For the Brisbane<br />
<strong>Water</strong> sites, monitoring should be carried out at the same stage of the tide (preferably high water<br />
slack +/- 1 hour).<br />
To determine antecedent rainfall, <strong>Council</strong> should operate and maintain at least two rainfall gauges,<br />
one located on the coast, and the other located around Brisbane <strong>Water</strong> (possibly on top of the <strong>Council</strong><br />
building). Rainfall during the preceding 48 hours, and 7 day periods should be recorded as part of the<br />
water quality monitoring data.<br />
4.5.2 Option 2: Catchment and Receiving <strong>Water</strong> Monitoring<br />
This option involves monitoring the catchment-based inputs to the waterways, and the response of the<br />
waterways to these inputs. The inputs would be determined by monitoring water quality during high<br />
flow periods only. Given that it is the high flows that provide the vast majority of pollutants to the<br />
waterways, only high flows will be targeted. Actual pollutant loads will be calculated based on<br />
measured concentrations and flow rates. To enable effective monitoring of high flows, it is suggested<br />
that automatic samplers are installed within the catchment. These devices automatically extract a<br />
sample from the tributary when triggered, and store the sample (refrigerated if necessary) until<br />
collection. A flow measuring device would also be required in order to quantify the pollutant loads<br />
within the tributary, and possibly to trigger the auto-sampling (when flows exceed a given level).<br />
As a pilot study, it is recommended that monitoring be triggered during a 1 in 1 month high flow<br />
event, with approximately 3 samples taken during the course of the event.<br />
The response monitoring would involve hand collection of samples. It is suggested that sampling be<br />
done at various times after the triggered event (1 in 1 month as a pilot study), for example 24 hours,<br />
48 hours, and 7 days after the event. The response monitoring sites would be downstream of the<br />
catchment input site, and would represent the wider receiving water body of the catchment waterway.<br />
Where possible, one of the response sites should be consistent with the historical water quality<br />
monitoring sites, so that comparisons can be made with past results (eg previous sites in Narara<br />
Creek, Erina Creek and Kincumber Creek).<br />
Parameters analysed for both the input and response sites would be comparable to those outlined in<br />
Option 1, including both the physical and chemical constituents, as well as chlorophyll-a and bacteria.<br />
Algal monitoring could also be considered as part of the response monitoring, but not the input<br />
monitoring.<br />
Given that this approach would focus on water quality monitoring of specific sections of the <strong>Gosford</strong><br />
catchment only, with the remainder left largely unmonitored, this option should target the worst<br />
effected sections of the waterways (i.e. greatest potential catchment input, most susceptible area to<br />
inputs, etc). Also, given the relatively high capital costs of installing the auto-samplers, it is<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-16<br />
suggested that a pilot study be initiated in one subcatchment. Funds for future years could then be put<br />
towards the capital costs of installing additional auto-samplers. Alternatively, funds for the capital<br />
costs could be sourced separately, as the auto-samplers would represent assets of <strong>Council</strong>.<br />
4.5.3 Option 3: Quarterly Seagrass Depth Monitoring<br />
This option follows that carried out as part of the Coastal CRC<br />
EHMP, and involves surveying the seaward extent of seagrass<br />
growth at numerous locations around the waterways. The depth to<br />
which seagrasses grow is essentially limited by the penetration of<br />
light through the water. Areas of higher turbidity and pelagic algae<br />
tend to have shallower seagrass depth limits than more pristine areas.<br />
Seagrass depth limits tend to vary on a seasonal basis, hence the need<br />
for monitoring every 3 months or so. Comparisons should be made<br />
with the same period in previous years.<br />
The locations should include at least two control sites, in addition to<br />
the impact sites. Locations should be chosen to try and avoid areas<br />
where seagrass growth may be inhibited by physical factors, such as<br />
propeller boat wash or high tributary flows.<br />
Monitoring would involve establishing temporary shore-based benchmarks for three transects at each<br />
location. Transects would be surveyed as shoreline cross-sections, noting the variation in seagrass<br />
along each transect to the point where seagrass is no longer present.<br />
Seagrass depth monitoring would be best done to supplement another monitoring program, be it<br />
water quality, sediment quality or biological monitoring.<br />
4.5.4 Option 4: Quarterly Benthic Macroinvertebrate Monitoring<br />
This option involves monitoring of benthic macroinvertebrates from a number of locations around the<br />
waterways. A very carefully designed program would be necessary to address the natural variability<br />
in benthic population. This would involve having multiple control sites, and nesting both control and<br />
impact sites together, with four replicates at each site.<br />
Monitoring would be done either in the intertidal zone using cores, or in the subaqueous zone using<br />
grabs. Monitoring would need to be carried out on a quarterly basis to take into account the seasonal<br />
variability in benthic community abundance and diversity.<br />
In addition to benthic macroinvertebrates, sediment samples should be collected and analysed for TP,<br />
TN and TOC, with at least three replicates of sediment quality at each location. Correlations could<br />
then be performed between the sediment quality and the benthic macroinvertebrate population.<br />
Particle size distribution analysis of the sediment would also be required in order to characterise the<br />
benthic sedimentary environment.<br />
Comparisons would be drawn between the control and impact sites, with conclusions stating that the<br />
results from the impact sites fall either within or outside the natural variability experienced by the<br />
control sites. Care would be required when interpreting the results, as the results may only provide an<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-17<br />
indication of the health of the waterway sediments, rather than the overlying water quality and<br />
general environmental health.<br />
4.5.5 Indicative Costs of Options<br />
The indicative costs for the various options are presented in Table 4.1 for <strong>Council</strong>’s consideration.<br />
Table 4.1<br />
Indicative Costs for Future Monitoring Options<br />
Option Description<br />
Annual cost<br />
Option 1: Routine Monthly <strong>Water</strong> <strong>Quality</strong> Monitoring<br />
WQ analysis for 10 sites................................................................<br />
Additional sites ..............................................................................<br />
Collection of samples from the field.............................................<br />
Interpretation and reporting of results...........................................<br />
Set-up and survey of tideboards in lagoons ..................................<br />
Set-up of rainfall gauge .................................................................<br />
Faecal sterols assessment (optional) .............................................<br />
Option 2: Catchment and Receiving <strong>Water</strong> Monitoring<br />
Auto-sampler .................................................................................<br />
WQ analysis for 1 input and 2 response sites (based on 3<br />
samples per month for each, capturing the 1 in 1 month event)...<br />
Collection of samples from the field.............................................<br />
Interpretation and reporting of results...........................................<br />
$31,200<br />
$2,600 each<br />
$7,200<br />
$7,200<br />
$2,000 (one-off cost)<br />
$1,000 each (one-off cost)<br />
$150 per sample<br />
$20,000 each (one-off cost)<br />
$24,800 per sampler<br />
$7,200<br />
$7,200<br />
Option 3: Quarterly Seagrass Depth Monitoring<br />
8 – 10 sites (incl. at least 2 control sites), with three transects at<br />
each site..........................................................................................<br />
Interpretation and reporting of results...........................................<br />
Establish temporary survey marks for each transect ....................<br />
$12,000<br />
$3,000<br />
$3,000 (one-off cost)<br />
Option 4: Quarterly Benthic Macroinvertebrate Monitoring<br />
8 sites (4 nested pairs), incl. 4 control sites, with 4 replicates at<br />
each site..........................................................................................<br />
Interpretation (stats) and reporting ................................................<br />
Additional nested pair sites (incl. additional interpret &<br />
reporting)........................................................................................<br />
Sediment quality analysis ..............................................................<br />
Sediment particle size distribution (PSD) analysis.......................<br />
$25,600<br />
$12,800<br />
$12,000 each<br />
$6,800<br />
$3,200<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-18<br />
4.5.5.1 Assumptions in Determining Costs<br />
Please note that there were a few assumptions made when determining the indicative costs.<br />
• Costs for water quality and sediment quality analyses were based on commercial analytical<br />
laboratory rates. The use of <strong>Council</strong>’s public health laboratory may reduce costs, however, this<br />
would mean the analysis would not be carried out by a NATA accredited laboratory. It is<br />
expected that <strong>Council</strong>’s laboratory would not be able to carry out all of the analyses (especially<br />
sediment quality, chlorophyll-a, and algal counts and composition). An external lab would need<br />
to be sub-consulted for these components at least.<br />
• <strong>Water</strong> quality monitoring costs assume both algal counts and composition would be required. If<br />
only algal counts were to be carried out (with no composition / speciation), costs could be<br />
reduced by at least $2,700pa. If no algal counts or composition data are required, costs could be<br />
reduced by $5,400pa. Conversely, if algal data are required for more than 3 sites, costs would<br />
increase by $1,800pa per site.<br />
• Collection, interpretation and reporting costs were based on an external consultant undertaking<br />
the works. Costs may be reduced if <strong>Council</strong> staff could perform one or more of these costs. It is<br />
understood that staff from the public health laboratory may be available for collection of water<br />
quality samples.<br />
• Costs for routine water quality monitoring could be reduced if the number of sites to be<br />
monitored is reduced. Given the community pressure for broadscale monitoring throughout the<br />
<strong>City</strong>, it is likely that only a couple of sites could be removed without significantly compromising<br />
the program, these being Booker Bay and possibly Cockle Broadwater. Savings would be<br />
approximately $2,600pa per site.<br />
• No allowance was made for incorporation of monitoring that will be carried out as part of future<br />
<strong>Council</strong> projects, such as that Brisbane <strong>Water</strong> Biodiversity Study and the Brisbane <strong>Water</strong> Estuary<br />
Processes Study.<br />
4.6 Recommended Monitoring Program<br />
One of the primary objectives of this document is the recommendation of a future monitoring<br />
program to be implemented by <strong>Council</strong>. The purpose of the future program would be to:<br />
• provide information to the community on the health of the waterways; and<br />
• assist <strong>Council</strong> in their sustainable natural resource management role.With regards to the second<br />
point, monitoring provides a justifiable basis for prioritisation of future remediation works (given<br />
limited funds for works implementation) and also provides a measure of the effectiveness of the<br />
works once implemented.<br />
<strong>Council</strong>’s current water quality budget ($40,000) is an obvious limitation to the option(s) that can be<br />
implemented immediately. The continuous water quality probes at Avoca Lagoon, Cockrone Lagoon<br />
and Koolewong that were utilised in the past provided limited information on overall environmental<br />
health of the waterways, and are not recommended to be continued. This does not preclude their<br />
value in providing useful scientific data regarding the environmental processes occurring within the<br />
waterways. However, given the costs to maintain the probes (~$16,000 pa), their benefit cost is<br />
limited.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-19<br />
With regard to water quality monitoring, it is recommended that Option 1 be implemented utilising<br />
the same 10 sites as was adopted by Cheng. This would maximise the value of the historical data in<br />
assessing water quality retrospectively. Providing additional information regarding the water levels<br />
and rainfall, whilst also being consistent with the stage of the tide (preferably high water slack), will<br />
ensure that the information gathered can be readily interpreted.<br />
It is also recommended that <strong>Council</strong> move towards carrying out seagrass depth monitoring. Whilst<br />
this may not be completely implementable within the first 12 months, it is strongly recommended that<br />
<strong>Council</strong> seek additional funds to carry out seagrass depth monitoring in the future. Once the transects<br />
and monitoring protocols are established, <strong>Council</strong> could consider the possibility of the works being<br />
done by <strong>Council</strong> staff (possibly a survey team). Alternatively, seagrass depth monitoring could be<br />
carried out periodically by students from a university or other tertiary institution, as part of an<br />
environmental science program.<br />
It is not recommended that <strong>Council</strong> undertake benthic macroinvertebrate monitoring (Option 4) as a<br />
sole indicator for environmental health in the <strong>Gosford</strong> waterways. Firstly, it would be difficult to<br />
monitor all of the different waterways in question within the designated budget, and indeed find<br />
relevant control sites for the different types of waterways, especially the coastal lagoons. Secondly,<br />
considerable effort will be needed to appreciate the natural variability in benthic communities.<br />
Nonetheless, <strong>Council</strong> should explore possibilities of utilising Universities and other research<br />
organisations to carry out periodic benthic community assessments. The information gained from<br />
these assessments could be fed into <strong>Council</strong>’s broader assessment of environmental health using other<br />
indicators, such as water quality (and possibly seagrass depth limits). It is understood that the<br />
University of Newcastle is currently undertaking ecological research in Brisbane <strong>Water</strong> as part of a<br />
Biodiversity Study. Continuation of this program in the future, and other similar programs, should be<br />
encouraged.<br />
Option 2 is also not recommended, as it would focus on only very limited sections of the LGA. It<br />
would be difficult for <strong>Council</strong> to extrapolate the results and make comment regarding the overall<br />
environmental health of the <strong>Gosford</strong> waterways, unless numerous catchment and receiving water<br />
monitoring programs were set-up throughout the <strong>City</strong>. Option 2 represents an expensive ‘rolls royce’<br />
solution to water quality monitoring in the <strong>Gosford</strong> LGA.<br />
A summary of the parameters that need to be included in the future monitoring program is provided<br />
in Table 4.2, while the locations of the sampling sites are provided in Figure 4.10 and Figure 4.11.<br />
Note that the monitoring program should be carried out on the same day of each month to ensure<br />
consistency. For simplicity, it is recommended that this be the first day of the month (or closest<br />
following working day).<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-20<br />
Table 4.2<br />
Parameters to be monitored<br />
In-situ monitoring<br />
(monthly at high water slack)<br />
Sample & lab analysis<br />
(monthly at high water slack)<br />
Additional site information<br />
(monthly at high water slack)<br />
• Dissolved oxygen<br />
• pH<br />
• Turbidity<br />
• Temperature<br />
• Salinity / conductivity<br />
• Biochemical Oxygen Demand (BOD)<br />
• Ammonia<br />
• Oxidised nitrogen<br />
• Total Kjeldahl Nitrogen (TKN)<br />
• Total nitrogen<br />
• Orthophosphate<br />
• Total phosphorus<br />
• Suspended solids<br />
• Chlorophyll-a<br />
• Algal counts (3 sites only) (1)<br />
• Enterococci (or Faecal sterols) (2)<br />
• <strong>Water</strong> level (relative to surveyed tide board) (3)<br />
• Rainfall during preceding 48 hours (4)<br />
• Rainfall during preceding 7 days (4)<br />
• Entrance condition (lagoons only)<br />
1) Algal counts are recommended to be measured at the Cockrone Lagoon, Terrigal Lagoon and<br />
Woy Woy Creek sites.<br />
2) Faecal sterols should be substituted for Enterococci is there are sufficient funds available.<br />
Commercial faecal sterols analysis can be carried out locally at the University of Newcastle for<br />
less than $150 per sample (compared to approximately $30 per sample for enterococci, i.e. an<br />
extra $14,400 is required)<br />
3) Tide boards will need to be installed and surveyed to a standard datum prior to the<br />
commencement of water quality monitoring.<br />
4) Rainfall to be measured by automated local rain gauges, one located near the coastal lagoons<br />
(eg on the roof of a <strong>Council</strong> owned childcare centre), and one located closer to Brisbane <strong>Water</strong><br />
(eg on the roof of Mann Street <strong>Council</strong> building).<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-21<br />
Figure 4.10 General Locations of Future Monitoring Sites<br />
Figure 4.11 continued over page<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-22<br />
Figure 4.11 Detailed Locations of Monitoring Sites<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
FUTURE DIRECTIONS FOR WATER QUALITY / ENVIRONMENTAL HEALTH MONITORING 4-23<br />
4.6.1 Recommendations for a <strong>Gosford</strong> Environmental Health Indicator<br />
Based on the Coastal CRC EHMP template, an appropriate Environmental Health Indicator for the<br />
<strong>Gosford</strong> water would incorporate the results of both biotic and abiotic assessments. As a minimum, it<br />
is recommended that the following be integrated into an Environmental Health Indicator:<br />
• <strong>Water</strong> <strong>Quality</strong> (as defined by Compound <strong>Water</strong> <strong>Quality</strong> Index or associated scorecards);<br />
• Seagrass depth assessment (as and when the opportunity arises to incorporate seagrass<br />
monitoring into routine <strong>Council</strong> environmental assessment programs); and<br />
• Benthic macroinvertebrate assessment (based on the initial Biodiversity Study by University of<br />
Newcastle [Dr Bill Gladstone], and assuming that repeatable assessments could be carried out at<br />
least annually as part of <strong>Council</strong>’s future environmental monitoring programs).<br />
In the first instance, however, it is likely that the only measure of Environmental Health will be the<br />
Compound <strong>Water</strong> <strong>Quality</strong> Index, as described in Section 3.1.3. The limitation of assessing only<br />
abiotic parameters, needs to be recognised though.<br />
With regard to the Compound <strong>Water</strong> <strong>Quality</strong> Index, or more specifically the <strong>Water</strong> <strong>Quality</strong><br />
Scorecard, objectives can be set for different locations based on an understanding of the estuarine<br />
processes throughout the <strong>Gosford</strong> waterways. Recommended targets for future water quality scores<br />
are shown in Table 4.3.<br />
Table 4.3<br />
Recommended <strong>Water</strong> <strong>Quality</strong> Scores for different sections of the<br />
<strong>Gosford</strong> <strong>Water</strong>ways<br />
Location<br />
<strong>Water</strong> <strong>Quality</strong><br />
Score<br />
Additional Objectives<br />
Lower Brisbane <strong>Water</strong> (e.g. Booker Bay) 10/10<br />
Upper Brisbane <strong>Water</strong> (e.g. Koolewong) 9/10<br />
Brisbane <strong>Water</strong> tributaries 8/10 Ammonia < 0/01 mg/L<br />
NO x < 0.02 mg/L<br />
Coastal Lagoons 8/10 Chlorophyll < 2 µg/L<br />
Recommendations regarding seagrasses and benthic macroinvertebrates, along with guidelines for<br />
amalgamating results into one ‘Environmental Health Index’ would be determined following baseline<br />
monitoring of the biological components.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
REFERENCES 5-1<br />
5 REFERENCES<br />
AWT (2001) <strong>Gosford</strong> <strong>Water</strong> <strong>Quality</strong> Survey Stage 2 Report – Major Tributary <strong>Water</strong> <strong>Quality</strong><br />
Assessment Information, Australian <strong>Water</strong> Technology, December 2001<br />
Coates B, Junes AR, Williams RJ (2002) Is ‘Ecosystem Health’ a Useful Concept for Coastal<br />
Managers? Coast to Coast 2002, pp 55 - 58<br />
Cheng D (1994), Environmental Study of Brisbane <strong>Water</strong>s, University of Technology Sydney,<br />
September 1994.<br />
Cheng D (2001), <strong>Water</strong> <strong>Quality</strong> Monitoring of Brisbane <strong>Water</strong> and <strong>Gosford</strong> Lagoons, University of<br />
Technology Sydney, Insearch, Project Number: E99/62/006, 29 March 2001.<br />
Coastal CRC web-site www.coastal.crc.org.au<br />
Ecoscience Technology (2002), <strong>Water</strong> <strong>Quality</strong> and Biological Monitoring of Brisbane <strong>Water</strong> and<br />
<strong>Gosford</strong> Lagoon, prepared for <strong>Gosford</strong> <strong>City</strong> <strong>Council</strong>.<br />
Ecoscience Technology (2000) Phytoplankton Monitoring of Brisbane <strong>Water</strong>s and <strong>Gosford</strong> Lagoons,<br />
prepared for <strong>Gosford</strong> <strong>City</strong> <strong>Council</strong>, May 2000.<br />
Ecoscience Technology (2000b) Phytoplankton Monitoring of Brisbane <strong>Water</strong> and <strong>Gosford</strong> Lagoons,<br />
prepared for <strong>Gosford</strong> <strong>City</strong> <strong>Council</strong>.<br />
Insearch (2000) <strong>Water</strong> <strong>Quality</strong> Monitoring of Brisbane <strong>Water</strong> and <strong>Gosford</strong> Lagoons, prepared for<br />
<strong>Gosford</strong> <strong>City</strong> <strong>Council</strong>, Insearch Ltd.<br />
JH & ES Laxton (1994), <strong>Water</strong> <strong>Quality</strong> of <strong>Gosford</strong> Lagoons, JH & ES Laxton Environmental<br />
Consultants Pty Ltd, October 1994.<br />
JH & ES Laxton (1999), <strong>Water</strong> <strong>Quality</strong> of <strong>Gosford</strong> Lagoons and Brisbane <strong>Water</strong> (1996 – 98), JH &<br />
ES Laxton Environmental Consultants Pty Ltd, February 1999.<br />
Webb, McKeown & Associates Pty Ltd (1995), <strong>Gosford</strong> Coastal Lagoons Estuary Processes Study,<br />
Prepared for <strong>Gosford</strong> <strong>City</strong> <strong>Council</strong>.<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
MHL DATASONDE RESULTS: AVOCA LAGOON A-1<br />
APPENDIX A: MHL DATASONDE RESULTS: AVOCA LAGOON<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
MHL DATASONDE RESULTS: COCKRONE LAGOON B-1<br />
APPENDIX B: MHL DATASONDE RESULTS: COCKRONE LAGOON<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11
MHL DATASONDE RESULTS: KOOLEWONG C-1<br />
APPENDIX C: MHL DATASONDE RESULTS: KOOLEWONG<br />
D:\R.N0754.002.01.DOC 7/11/03 16:11