HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page i 301020-03413 : 210 FINAL DRAFT: October 2013
Water Quality Study
Burwood Beach WWTW
301020-03413 – 210
October 2013
Infrastructure & Environment 3 Warabrook Boulevard Newcastle, NSW 2304 Australia PO Box 814 NEWCASTLE NSW 2300 Telephone: +61 2 4985 0000 Facsimile: +61 2 4985 0099 www.worleyparsons.com ABN 61 001 279 812
© Copyright 2013 WorleyParsons
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
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SYNOPSIS
The Burwood Beach Water Quality Study was undertaken to characterise the extent of impacts on the
receiving environment from effluent and waste activated sludge (biosolids) discharges and to define
the near, mid and farfield impacts of the effluent and biosolids plume. The primary objectives of the
water quality monitoring study were to:
Measure physicochemistry parameters and concentrations of nutrients, chlorophyll a and faecal
indicators in the receiving environment, at a range of distances from the outfall, to assess the
gradient of potential impact;
Compare data with relevant guidelines to identify compliance (where applicable). This includes
the Australian and New Zealand Environment and Conservation Council (ANZECC)
Guidelines for Fresh and Marine Water Quality (2000), the New South Wales Environmental
Protection Authority (NSW EPA) Marine Water Quality Guidelines (2000) and the National
Health and Medical Research Council (NHMRC) Guidelines for Managing Risks in
Recreational Waters (2008); and
Measure the footprint of impact on the receiving environment.
Water sampling was undertaken at 32 sites, which were selected in a regularly spaced radial
arrangement around the outfall diffusers (at distances of 0 m, 30 m, 100 m, 250 m, 500 m and 2 km).
The location of sampling sites took into account the locations of the effluent and biosolids outfalls,
prevailing hydrodynamic conditions in the area and plume characteristics. For some summaries, the
distances were also divided into three zones which included the outfall zone (0 and 30 m), the mixing
zone (100, 250 and 500 m) and the reference zone (2 km).
A suite of parameters, including physiochemical, nutrients, chlorophyll a and faecal indicators, were
measured at each site (Table 1). Measurements of physicochemistry and chemistry sampling were
undertaken at two depths (surface and mid-water). A total of 64 water column samples were collected
during each sampling event to test for nutrients, chlorophyll a and faecal indicators (i.e. 32 sites x 2
depths).
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Table 1 Analytical parameters showing their respective LOR and guideline values.
Analytical Parameter Limit of Reporting
(LOR)
Guideline Guideline reference
In-situ physico-chemical
Secchi-disc depth 0.5 m 1.6 m NSW EPA (2000); ANZECC (2000)
Turbidity 0.1 NTU 6 NTU ANZECC (2000)
Temperature 0.01 °C 15-35 °C NSW EPA (2000)
Electrical Conductivity 0.01 mS/cm None defined
Salinity 0.01 ppt None defined
Dissolved Oxygen mg/L None defined (in mg/L) 6
pH 0.1 8 - 8.4 ANZECC (2000)
Nutrients
Organic Nitrogen as N 5 0.01 mg/L None defined
Ammonia as N 0.005 mg/L 0.02 mg/L
0.5 mg/L7
ANZECC (2000)
ANZECC (2000)
Nitrite + Nitrate (NOx) 0.002 mg/L 0.025 mg/L ANZECC (2000)
Dissolved Inorganic Nitrogen (NH3 + NOx)
3 0.005 mg/L None defined
Total Nitrogen as N 4, 5
0.01 mg/L 0.12 mg/L
NSW EPA (2000); ANZECC (2000)
Total Phosphorus as P 0.005 mg/L 0.025 mg/L NSW EPA (2000); ANZECC (2000)
Chlorophyll a 1 0.5 mg/m
3 (i.e. 0.5
µg/L) 1 mg/m
3 ANZECC (2000)
Thermotolerant Faecal Coliforms 2, 9
1 CFU/100 mL 50% of values ≤150 CFU/100 mL
ANZECC (2000)
Enterococci 2, 8
1 CFU/100 mL 95th percentile of values ≤40 CFU/100 mL
NHMRC (2008)
1 Note that an LOR of 1 mg/m
3 was used for chlorophyll a for the first two sampling events, as per the original agreement
between WorleyParsons, the analytical laboratory and Hunter Water. This LOR was subsequently changed to 0.5 mg/m3.
2 Note that for turbid water samples the analytical laboratory advised that the LOR for microbial samples may need to increase
to 2 CFU / 100 ml. This would be based on visual inspection at the laboratory and cannot be based on any predetermined turbidity value.
3 Dissolved parameters (i.e. dissolved inorganic nitrogen) required field filtering.
4 Note that total nitrogen is calculated by the laboratory as a separate analysis and is not determined by calculation (i.e. may
not always equal the sum of nitrogen components as provided in the data).
5 Note that an LOR of 0.05 mg/L
was used for organic nitrogen and total nitrogen for the first two sampling events, this LOR was
subsequently changed to 0.01 mg/L in later sampling rounds.
6 ANZECC Guideline for dissolved oxygen is 90 to 110 % saturation; however dissolved oxygen was measured in mg/L in this
study.
7 Note this refers to ANZECC (2000) default trigger value for ammonia for 99% level of protection of species in marine waters.
8 Note that ANZECC refers to NHMRC 2008 “Guidelines for Managing Risks in Recreational Waters”. These NHMRC Guidelines recommend a 95 % enterococci limit of < 40 cfu/100 mL as this value is below the NOAEL in most epidemiological studies and the AFRI would be negligible.
9 Note that Faecal coliforms are considered by the NHMRC as an unsuitable regulatory parameter but still form part of NSW Water Quality Guidelines with the limit being 50 % < 150 cfu/100 mL.
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Overall ammonia, total nitrogen, chlorophyll a, enterococci and faecal coliforms and to a more limited
extent, total phosphorus, had patterns of decreasing concentrations with distance from the outfall,
suggesting that the Burwood Beach WWTW outfalls are the main source of these components in the
receiving environment. Conversely, in some sampling events, levels of total nitrogen, nitrites +
nitrates and occasionally chlorophyll a were elevated at similar levels across all sites, including outfall,
mixing zone and reference sites.
A trigger index was created which provides a single value to represent the frequency and magnitude
of various parameters that exceeded the respective water quality guideline (i.e. ANZECC 2000; EPA
2000 or NMHRC 2008) across site and depth. The application of the trigger index shows the
frequency and magnitude that the results exceeded the water quality guidelines. In particular,
ammonia, total phosphorus, enterococci and faecal coliforms exceeded the guidelines around the
outfall and then mixing zone with a higher magnitude and frequency in comparison to the reference
sites.
Multivariate analysis suggests that the main factor that influenced the multivariate water quality profile
(which consisted of the results of the nutrients, chlorophyll a and faecal indicators) was sampling time.
Multidimensional scaling (MDS) plots show that samples taken within the same day or within the
same sampling event are the most similar. This shows that temporal variability is the largest cause
of variability in the water quality dataset, which is not surprising or uncommon in marine water quality
programs. In a Permanova analysis, distance based linear modelling (DISTLM), sample time was
found to be a statistically significant predictor of water quality (p value < 0.001) accounting for 61% of
the variation in the multivariate results. The influence of daily variation was eliminated by holding the
factor of daily variation constant in a sequential analysis. The factor of distance from the outfall was
then found to be significant factor (p = 0.001, R2 = 6.5%). This result shows, that despite the day to
day variability, distance from the outfall is a significant predictor of water quality. This shows that
while sample date is the largest contributor to variability in the water quality multivariate profile,
distance from the outfall is still a significant factor which can be detected despite temporal variability.
Other factors that were examined but did not explain the variability in water quality results included
sampling event, season, sampling year, direction from the outfall, depth at site and rainfall in the
preceding days.
The median and 95th percentile water quality results for key parameters are outlined in Table 2.
Overall, the results of the Burwood Beach Water Quality Study suggest that the Burwood Beach
outfall is having an effect on local water quality at distances of at least 500 m from the diffusers.
There is a clear pattern of decreasing concentrations, with higher results in the outfall and mixing
zones in comparison to the reference zone, for the parameters of ammonia, organic nitrogen,
inorganic nitrogen, total nitrogen, total phosphorus, enterococci and faecal coliforms.
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Table 2: Summary of median and 95th percentile data by zone
Parameter
Median Level 95th percentile Guideline
Value
outfall mixing zone reference outfall mixing zone reference
Turbidity (NTU) 2.60 2.40 1.45 12.80 7.16 9.79 61
Temperature (oC) 18.44 18.95 20.63 22.90 22.90 23.10 15- 35
2
Conductivity 5.50 5.50 5.50 5.67 5.67 5.68 -
Dissolved oxygen 7.49 7.40 7.25 9.62 9.69 9.82 -
pH 8.32 8.28 8.27 8.45 8.45 8.39 8- 8.41
Ammonia as N (mg/L) 0.017 0.003 0.003 0.093 0.060 0.021 11
Organic Nitrogen as N (mg/L) 0.115 0.080 0.080 0.230 0.200 0.282 -
Nitrite + Nitrate as N (mg/L) 0.005 0.003 0.003 0.087 0.079 0.073 0.0251
Inorganic Nitrogen as N (mg/L) 0.031 0.012 0.006 0.127 0.079 0.060 -
Total Nitrogen as N (mg/L) 0.160 0.100 0.100 0.340 0.220 0.353 0.111,2
Total Phosphorus as P (mg/L) 0.013 0.009 0.008 0.033 0.020 0.017 0.0251,2
Chlorophyll a (mg/m3) 0.50 0.50 0.25 2.00 1.75 0.80 1
Faecal Coliforms (CFU/100ml) 125.00 6.00 0.50 757.00 202.50 54.60
50% of values < 150
1
Enterococci (CFU/100ml) 26.50 4.00 1.00 180.00 108.00 16.90 95th percentile
< 40 3
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
Based upon the findings of this study, future increases in effluent and biosolids discharges from the
Burwood Beach WWTW is likely to result in continued impacts to water quality, especially for nutrients
and faecal indicators. This would be dependent on a number of factors including the rate of
discharge, concentrations in the effluent and the dilution in the receiving environment.
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Disclaimer
This report has been prepared on behalf of and for the exclusive use of Hunter Water, and is
subject to and issued in accordance with the agreement between Hunter Water and
WorleyParsons. WorleyParsons accepts no liability or responsibility whatsoever for it in respect of
any use of or reliance upon this report by any third party.
Copying this report without the permission of Hunter Water or WorleyParsons is not permitted.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
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Internal and Client Review Record
PROJECT 301020-03413 – BURWOOD BEACH WATER QUALITY STUDY
REV DESCRIPTION ORIG REVIEW WORLEY-
PARSONS APPROVAL
DATE CLIENT APPROVAL
DATE
A Draft issued for internal review
J Pallot
Dr K Newton
29 Jan 2012 N/A
B Draft issued for internal review
Dr K Newton
S Codi King
4 Feb 2012
C Draft issued for client review
Dr K Newton / J Pallot
Hunter Water / CEE
14 Feb 2012
D Draft issued for internal review
J Pallot
Dr M Holloway / Dr K Newton
5 Sept 2012
E Draft issued for internal review
J Pallot / Dr K Newton
S Codi King 5 Sept 2012
F Draft 2 issued for client review
Dr K Newton Hunter Water / CEE
6 Sept 2012
G Draft issued for internal review
J Pallot Dr K Newton 30 Oct 2012
H Draft 3 issued for client review
Dr K Newton Hunter Water / CEE
31 Oct 2012
I Draft 4 issued for internal
J Pallot / Dr K Newton
Dr K Newton / S Codi King
15 May 2013
J Draft 4 issued for internal review
J Pallot / Dr M Priestley/ Dr K Newton
S Codi King 30 May 2013
K Final draft issued to client
Dr K Newton / Dr M Priestley
Hunter Water / CEE
October 2013
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CONTENTS
1 INTRODUCTION ................................................................................................................ 1
1.1 Burwood Beach WWTW ..................................................................................................... 1
1.1.1 Treatment Process ................................................................................................. 1
1.1.2 Environmental Protection Licence Conditions ....................................................... 1
1.1.3 Characteristics of Current Effluent and Biosolids Discharges ............................... 4
1.1.4 Effluent and Biosolids Flow Data ......................................................................... 12
1.1.5 Dilution Modeling / Dispersion Characteristics .................................................... 13
1.2 Burwood Beach Marine Environmental Assessment Program ......................................... 14
1.2.1 Initial Consultation ................................................................................................ 14
1.3 Study Area ........................................................................................................................ 15
1.4 Scope of Work / Study Objectives .................................................................................... 15
1.4.1 Null Hypothesis .................................................................................................... 15
1.5 Review of Previous Studies .............................................................................................. 16
1.5.1 Burwood Beach WWTW Water Quality Studies .................................................. 16
2 METHODS ........................................................................................................................ 17
2.1 Sampling Sites .................................................................................................................. 17
2.2 Temporal Assessment ...................................................................................................... 21
2.2.1 Rainfall Prior to Sampling .................................................................................... 21
2.3 Sampling Methods ............................................................................................................ 26
2.3.1 In-situ Physicochemical Water Quality Measurements........................................ 26
2.3.2 Water Quality Sampling ....................................................................................... 26
2.4 Quality Assurance / Quality Control .................................................................................. 29
2.5 Data Management ............................................................................................................ 29
2.6 Data Analysis .................................................................................................................... 30
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2.6.1 Summary Statistics .............................................................................................. 30
2.6.2 Comparison to Water Quality Guidelines ............................................................. 30
2.6.3 Trigger Index ........................................................................................................ 31
2.6.4 Multivariate Analysis ............................................................................................ 32
3 RESULTS ......................................................................................................................... 34
3.1 Data Summaries ............................................................................................................... 34
3.1.1 Sampling Event .................................................................................................... 34
3.1.2 Zone ..................................................................................................................... 43
3.2 Physicochemical Parameters ........................................................................................... 45
3.3 Nutrients, chlorophyll a and faecal indicators ................................................................... 52
3.3.1 Nitrogen Forms .................................................................................................... 52
3.3.2 Total Phosphorus ................................................................................................. 58
3.3.3 Chlorophyll a ........................................................................................................ 59
3.3.4 Faecal Indicators .................................................................................................. 60
3.3.5 Summary of Signature Parameters by Zone ....................................................... 62
3.4 Comparison of Results to Water Quality Guidelines ........................................................ 63
3.4.1 Summary .............................................................................................................. 63
3.4.2 Trigger Index ........................................................................................................ 68
3.5 Multivariate Data Analysis ................................................................................................ 77
3.5.1 Multidimensional Scaling ..................................................................................... 77
3.5.2 Multivariate Multiple Regression (DISTLM) ......................................................... 81
4 DISCUSSION .................................................................................................................... 86
4.1 Water Quality Study .......................................................................................................... 86
4.1.1 Physicochemistry and Qualitative Parameters .................................................... 86
4.1.2 Nutrients, Chlorophyll a and Faecal Indicators .................................................... 87
4.1.3 Analysis of Water Quality Data (nutrients, chlorophyll a and faecal indicators) .. 89
4.2 Patterns between Water Quality Results and Effluent and Biosolids Composition .......... 91
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5 CONCLUSIONS ................................................................................................................ 93
6 ACKNOWLEDGEMENTS ................................................................................................. 95
7 REFERENCES ................................................................................................................. 96
Appendices
APPENDIX 1 – COC FORMS FOR WATER QUALITY ANALYSIS
APPENDIX 2- RAW WATER QUALITY DATA
APPENDIX 3- CEE ANALYSIS OF WATER QUALITY DATA BY ZONE
Figures
Figure 1.1 Location of Burwood Beach WWTW.
Figure 1.2 Burwood Beach WWTW and outfall alignment.
Figure 1.3 Burwood Beach flow data for the study period (July 2011 - May 2013).
Figure 2.1 Water quality sampling sites.
Figure 2.2 Water quality sampling sites close to the Burwood Beach diffusers.
Figure 2.3 Rainfall data for the sampling month.
Figure 2.4 Water sampling equipment.
Figure 3.1 Secchi disc depth.
Figure 3.2 Turbidity.
Figure 3.3 Temperature.
Figure 3.4 Conductivity.
Figure 3.5 Dissolved oxygen.
Figure 3.6 pH.
Figure 3.7 Ammonia as N.
Figure 3.8 Organic Nitrogen as N.
Figure 3.9 Nitrite + Nitrate as N.
Figure 3.10 Inorganic Nitrogen as N
Figure 3.11 Total Nitrogen as N.
Figure 3.12 Total Phosphorus as P.
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Figure 3.13 Chlorophyll a.
Figure 3.14 Enterococci.
Figure 3.15 Faecal coliforms.
Figure 3.16 Trigger index values for all parameters by distance from the outfall.
Figure 3.17 Trigger index values for ammonia by distance from the outfall for each sampling event.
Figure 3.18 Trigger index values for nitrites + nitrates by distance from the outfall for each sampling
event.
Figure 3.19 Trigger index values for total nitrogen by distance from the outfall for each sampling
event.
Figure 3.20 Trigger index values for total phosphorus by distance from the outfall for each sampling
event.
Figure 3.21 Trigger index values for chlorophyll a by distance from the outfall for each sampling event.
Figure 3.22 Trigger index values for enterococci by distance from the outfall for each sampling event.
Figure 3.23 Trigger index values for faecal coliforms by distance from the outfall for each sampling
event.
Figure 3.24 MDS plot of multivariate water quality response data similarity matrix created using the
Gower metric. Symbols are plotted by sample date.
Figure 3.25 MDS plot of the multivariate water quality response data similarity matrix created using
the Gower metric. Samples are plotted by sampling event.
Figure 3.26 MDS plot of the multivariate water quality similarity matrix created using the Gower
metric. Samples are plotted by season with influential variables plotted as a vector overlay.
Figure 3.27 MDS plot of the multivariate water quality similarity matrix created using the Gower
metric. Samples are plotted by sampling year.
Figure 3.28 MDS plot of the multivariate water quality similarity matrix created using the Gower
metric. Samples are plotted by distance from the outfall in meters.
Figure 3.29 MDS plot of the multivariate water quality similarity matrix created using the Gower
metric. Samples are plotted by direction from the outfall.
Figure 3.30 Distance based redundancy analysis plot of the fitted multivariate regression model.
Samples collected in the same sampling year are categorised by coloured symbols.
Figure 3.31 Distance based redundancy analysis plot of the fitted multivariate regression model.
Samples collected in the same season are categorised by coloured symbols.
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Figure 3.32 Distance based redundancy analysis plot of the fitted multivariate regression model.
Samples collected in the same sampling event are categorised by coloured symbols.
Figure 3.33 Distance based redundancy analysis plot of the fitted multivariate regression model.
Samples collected on each day are categorised by coloured symbols.
Figure 3.34 Distance based redundancy analysis (dbRDA) plot of the fitted multivariate regression
model. Samples collected at each sampling distance from the outfall (in meters) are categorised by
coloured symbols.
Figure 4.1 Fortnightly testing of effluent characteristics during the Burwood Beach Water Quality
Study. Red days indicate the effluent or biosolids sampling dates that coincide (within the week prior
to) the closest to the water quality sampling. In effluent, a= ammonium nitrate, b= total nitrogen, c=
nitrates + nitrites, d= total nitrogen, e= total phosphorus and in biosolids, f= ammonium nitrate.
Tables
Table 1.1 Load limits for effluent and biosolids discharges
Table 1.2 Summary of physicochemical, nutrients, metal/metalloid and organics data in effluent
collected by Hunter Water during 2006 - 2013.
Table 1.3 Summary of physicochemical, nutrients, metal/metalloid and organics data in biosolids
collected by Hunter Water during 2006 - 2013.
Table 1.4 Rainfall, effluent and WAS flow data for the study period (July 2011 - May 2013
Table 1.5 Classification of zones based on prior effluent dilution modelling.
Table 2.1 Location of sampling sites including distance and direction from the diffuser.
Table 2.2 Conditions for each water quality survey.
Table 2.3 Analytical parameters showing their respective LOR and guideline values.
Table 3.1 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in
July 2011, data pooled across sites.
Table 3.2 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in
October 2011, data pooled across sites.
Table 3.3 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in
February 2012, data pooled across sites.
Table 3.4 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in
April 2012, data pooled across sites.
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Table 3.5 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in
June 2012, data pooled across sites.
Table 3.6 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in
October 2012, data pooled across sites.
Table 3.7 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in
February 2013, data pooled across sites.
Table 3.8 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in
April 2013, data pooled across sites.
Table 3.9 Summary of median and 95th percentile data by zone
Table 3.10 Number and percentage of samples that exceeded the associated water quality guideline
Table 3.11 Results of the multivariate multiple regression analysis (DISTLM) applied to the water
quality similarity matrix.
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1 INTRODUCTION
1.1 Burwood Beach WWTW
The Burwood Beach Wastewater Treatment Works (WWTW) is located on the central coast region of
NSW approximately 2.5 km south of the city of Newcastle (Figure 1.1). The plant treats wastewater
from Newcastle and the surrounding suburbs, servicing approximately 185,000 people and local
industry. Average dry weather flow is 44 million litres of wastewater (44 ML/d). Over the next 30
years, these flows are expected to increase to 55 - 60 ML/d, even with water conservation measures
in place.
1.1.1 Treatment Process
The secondary treatment process at Burwood Beach consists of physical screening to remove large
and fine particulates, biological filtration and activated sludge processing including aeration and
settling stages. Secondary treated effluent from Burwood Beach WWTW is discharged to the ocean
through a multi-port diffuser which extends 1,500 m offshore, with diffusers at a depth of
approximately 22 m (Figure 1.2). Approximately 2 ML/d of waste activated sludge (biosolids), which
is surplus to treatment requirements, is also discharged to the ocean via a separate multi-port diffuser
that extends slightly further offshore than the effluent outfall. Both the effluent and biosolids outfalls
have been operating in their current configuration since January 1994.
1.1.2 Environmental Protection Licence Conditions
The Environment Protection Licence (EPL) for Burwood Beach WWTW specifies limit conditions for
the operation of the plant. These conditions provide an indication of the characteristics of the effluent
and biosolids discharged into the ocean. Condition L1 specifies that the operation of the outfall must
not cause or permit waters to be polluted (i.e. the licensee must comply with section 120 of the
Protection of the Environment Operations Act 1997). Condition L2 specifies limits relating to total
loads discharged to the ocean (including both the effluent and biosolids). These limits are provided in
Table 1.1. Condition 3 specifies limits to concentrations of suspended solids and oil / grease in the
effluent discharged to the outfall. The three day geometric mean concentration limit for suspended
solids is 60 mg/L and for oil / grease is 15 mg/L. Condition 4 sets volume and mass limits of effluent
and biosolids discharged via the outfalls. The limit for effluent flow rate is 510 ML/d (to allow for
higher flows in wet weather) and for biosolids the flow limit is 5 ML/d. Daily monitoring of flow is
required.
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Figure 1.1 Location of Burwood Beach WWTW.
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Figure 1.2 Burwood Beach WWTW and outfall alignment.
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Table 1.1 Load limits for effluent and biosolids discharges
Parameter Load Limits
kg/year kg/day
Total suspended solids 4,717,189 12,924
Biochemical oxygen demand - -
Total nitrogen 778,257 2,132
Oil and grease 341,290 935
Total phosphorus - -
Zinc 3,943 11
Copper 2,080 5.7
Lead 1,472 4.0
Chromium 224 0.61
Cadmium 124 0.34
Selenium 14 0.038
Mercury 9 0.025
Pesticides and PCBs 7 0.019
1.1.3 Characteristics of Current Effluent and Biosolids Discharges
The final treated effluent and biosolids from Burwood Beach WWTW has been monitored by Hunter
Water for physicochemical parameters, nutrients, and a suite of metals/metalloids and organic
chemicals. A summary of these data collected during the period 2006 - 2013 is provided in Tables
1.2 (effluent) and 1.3 (biosolids) (data courtesy of Hunter Water 2013).
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Table 1.2 Summary of physicochemical, nutrients, metal/metalloid and organics data in effluent collected by Hunter Water during 2006 - 2013.
Group Parameter (units) Period N Median Mean Min Max Std
Error 75%ile 90%ile
Physicochemical Suspended solids (mg/L) 2006-13 449 27 33.6 <1 390 1.6 40 60
UV254nm Transmittance (%T) 2006-13 6 59.2 58.4 43.6 68.31 3.4 62.475 65.705
pH 2006-13 224 7.6 7.6 7 8 0.01 7.7 7.8
Total dissolved solids (mg/L) 2006-13 56 440 448.5 276 734 12.9 487.5 545
Biological Oxygen Demand - total (mg/L) 2006-13 239 23 27.4 <2 144 1.3 36 50
Chemical Oxygen Demand - Flocculated (mg/L) 2006-13 19 42 41.8 32 55 1.6 46 51.4
Grease - total high range (mg/l) 2006-13 3 <5 4.7 <5 10 2.7 6 8.4
Grease - total low range (mg/l) 2006-13 444 <2 2.7 <2 60 0.2 3 5
Ammonium nitrogen (mg/L) 2006-13 70 23.0 21.7 1 33.1 0.8 26.8 29.4
Nitrate + nitrate oxygen (mg/L) 2006-13 236 1.0 1.6 <0.05 14 0.1 2.1 3.7
Total Kjeldahl Nitrogen (mg/L) 2006-13 236 26.9 26.1 2.2 48.7 0.6 33.0 36.9
Total nitrogen (mg/L) 2006-13 236 28.7 27.6 2.45 48.7 0.6 33.6 37.7
Total phosphorus (mg/L) 2006-13 236 2.3 2.64 0.09 8.2 0.11 3.625 4.8
Metals / Metalloids
Silver-Ag-AAS furnace (µg/L) 2006-13 31 1 3.1 <1 18 0.9 2.5 13
Silver Ag-ICP (µg/L) 2006-13 59 0.5 0.7 <1 7 0.1 0.5 1
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Group Parameter (units) Period N Median Mean Min Max Std
Error 75%ile 90%ile
Arsenic As-vga (µg/L) 2006-13 90 1.7 1.8 0.05 3.9 0.1 2.1 2.51
Cadmium Cd-furnace (µg/L) 2006-13 5 <1 <1 <1 <1 - <1 <1
Cadmium Cd-ICP (µg/L) 2006-13 59 <1 0.5 <1 1 <1 <1 <1
Chromium Cr-furnace (µg/L) 2006-13 31 1 1.9 <1 28 0.9 1.2 2
Chromium Cr- ICP (µg/L) 2006-13 59 <1 0.7 <1 2 0.1 0.75 1
Chromium Cr VI-furnace (µg/L) 2006-13 90 <1 0.7 <1 1 - 1 1
Copper Cu-furnace (µg/L) 2006-13 31 17 21.2 4 115 3.5 21 34
Copper Cu-ICP (µg/L) 2006-13 93 0.25 0.4 0.04 1.7 - 0.47 0.728
Mercury Hg-VGA (µg/L) 2006-13 90 <0.1 0.1 <0.1 1.6 - <0.1 0.2
Manganese Mn-furnace (µg/L) 2006-13 31 70 76.0 31 173 6.6 82 105
Manganese-ICP (µg/L) 2006-13 59 61 63.8 27 119 2.0 67.5 80.2
Nickel Ni-furnace (µg/L) 2006-13 90 <1 <1 <1 <1 - <1 <1
Nickel Ni-ICP (µg/L) 2006-13 59 4 5.3 <1 20 0.6 5.5 13.2
Lead Pb-furnace (µg/L) 2006-13 90 3 3.1 <1 17 0.3 4 5
Selenium Se-VGA (µg/L) 2006-13 90 0.1 0.3 <0.1 2 - 0.4 0.6
Zinc Zn (µg/L) 2006-13 31 50 49.4 10 120 4.3 55 70
Zinc Zn-ICP (µg/L) 2006-13 59 24 31.2 4 164 3.2 35 55.8
Organics Aldrin (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01
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Group Parameter (units) Period N Median Mean Min Max Std
Error 75%ile 90%ile
α-BHC Bhc-a (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01
β-BHC-b (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01
α Chlordane (µg/L) 2006-13 90 <0.01 0.000 <0.02 0.003 - <0.01 <0.01
Chlordane (µg/L) 2006-13 90 <0.01 0.001 <0.02 0.020 - <0.01 <0.01
λ Chlordane (µg/L) 2006-13 11 <0.01 0.000 <0.02 0.001 - <0.01 <0.01
Chlorpyrifos (µg/L) 2006-13 90 <0.01 0.007 <0.05 0.629 0.007 <0.01 <0.01
Lindane (µg/L) 2006-13 90 <0.01 0.000 <0.01 0.005 - <0.01 <0.01
DDT (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01
DDD (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01
DDE (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01
Diazinon (µg/L) 2006-13 90 <0.01 0.000 <0.1 0.030 - <0.01 <0.01
Dieldrin (µg/L) 2006-13 90 <0.01 0.000 <0.01 0.012 - <0.01 <0.01
Endosulfan (µg/L) 2006-13 0 <0.01
Endosulfan-s (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01
Endosulfan-1 (µg/L) 2006-13 0 <0.01
Endosulfan-2 (µg/L) 2006-13 0 <0.01
Endrin (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01
Heptachlor (µg/L) 2006-13 90 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005
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Group Parameter (units) Period N Median Mean Min Max Std
Error 75%ile 90%ile
HCB (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01
Heptachlor-epoxide (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01
Methoxychlor (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01
Parathion (µg/L) 2006-13 90 <0.1 0.000 <0.1 0.010 0.000 <0.1 <0.1
Total PCBs (µg/L) 2006-13 90 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
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Table 1.3 Summary of physicochemical, nutrients, metal/metalloid and organics data in biosolids collected by Hunter Water during 2006 - 2013.
Group Parameter (units) Period N Median Mean Min Max Std
Error 75%ile 90%ile
Physicochemical
Total solids (%w/w) 2006-13 458 0.41 0.45 0.00 2.42 0.01 0.50 0.67
Volatile solids (%w/w) 2006-13 440 69.12 66.35 20.61 96.72 0.51 72.68 74.60
Ammonium N_Total (mg/L N) 2006-13 440 24.00 25.03 0.01 85.40 0.55 30.13 39.00
Grease – total low range (mg/L) 2006-13 440 153.5 172.0 1.0 841.0 5.5 230.0 328.2
Fluoride (mg/L) 2006-13 3 0.77 0.67 0.42 0.82 0.13 0.80 0.81
Metals / Metalloids
Silver-Ag-AA Furnace (µg/L) 2006-13 152 22 23 4 63 1 29 40
Silver Ag-ICP (µg/L) 2006-13 279 11 12 0.5 38 0 15 18
Arsenic As-VGA (µg/L) 2006-13 431 14.7 18.33 2.6 130 0.70 19.75 30.5
Cadmium Cd-furnace (µg/L) 2006-13 152 4 5.93 0.5 128 1.04 6 8
Cadmium Cd-ICP (mg/L) 2006-13 279 0.005 0.01 0.005 0.06 0.00 0.01 0.01
Chromium Cr VI-furnace (µg/L) 2006-13 152 1 1.00 1 1 0.00 1 1
Chromium Cr VIi-furnace (µg/L) 2006-13 279 5 10 5 25 0.00 5 25
Chromium Cr-furnace (µg/L) 2006-13 152 46.5 68.16 1 750 7.41 68.5 105
Chromium Cr- ICP (µg/L) 2006-13 279 30 50 5 3200 10 40 70
Copper Cu-furnace (µg/L) 2006-13 152 839 954 125 3930 42.8 1134 1426
Copper Cu-ICP (µg/L) 2006-13 279 830 880 5 3300 20 1000 1300
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Mercury Hg- VGA µg/L) 2006-13 431 3.7 3.93 0.005 10.2 0.08 4.8 6.3
Manganese Mn-furnace (µg/L) 2006-13 152 339 360 33 1270 13.73 446.25 512.5
Manganese -ICP (mg/L) 2006-13 279 0.39 0.41 0.06 1 0.01 0.47 0.57
Nickel Ni-furnace (µg/L) 2006-13 152 40 47.21 13 180 2.49 55 77.7
Nickel Ni-ICP (mg/L) 2006-13 279 0.03 0.04 0.005 0.33 0.00 0.05 0.07
Lead Pb-furnace (µg/L) 2006-13 152 187 224 13 900 11.37 269.25 375
Lead Pb ICP µg/L) 2006-13 279 120 130 10 450 0.01 150 212
Selenium Se-VGA (µg/L)) 2006-13 431 0.1 0.91 0.05 5.9 0.06 1.7 2.7
Zinc Zn (mg/L) 2006-13 152 2.4 3.03 0.78 15.6 0.16 3.515 5.39
Zinc Zn-ICP (mg/L) 2006-13 279 2.2 2.46 0.13 6.9 0.06 2.8 3.7
Organics
Aldrin (µg/L) 2006-13 96 0 0 0 0 0 0 0
α-BHC Bhc-a (µg/L) 2006-13 96 0 0 0 0 0 0 0
β-BHC-b (µg/L) 2006-13 96 0 0 0 0 0 0 0
α Chlordane (µg/L) 2006-13 96 0 0 0 0 0 0 0
Chlordane (µg/L) 2006-13 96 0 0 0 0 0 0 0
λ Chlordane- (µg/L) 2006-13 13 0 0 0 0 0 0 0
Chlorpyrifos (µg/L) 2006-13 96 0 0.003 0 0.239 0.003 0 0
DDT (ug/L) 2006-13 96 0 0 0 0 0 0 0
DDD (µg/L) 2006-13 96 0 0 0 0 0 0 0
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DDE (µg/L) 2006-13 96 0 0 0 0 0 0 0
Diazinon (µg/L) 2006-13 96 0 0 0 0 0 0 0
Dieldrin (µg/L) 2006-13 96 0 0.006 0 0.315 0.004 0 0
Endosulfan-s (µg/L) 2006-13 96 0 0 0 0 0 0 0
Endrin (µg/L) 2006-13 96 0 0 0 0 0 0 0
HCB (µg/L) 2006-13 96 0 0 0 0 0 0 0
Heptachlor-epoxide (µg/L) 2006-13 96 0 0.0001 0 0.013 0.0001 0 2.8
Heptachlor (µg/L) 2006-13 96 0 0 0 0 0 0 0
Lindane (µg/L) 2006-13 96 0 0 0 0 0 0 0
Malathion (µg/L) 2006-13 96 0 0 0 0 0 0 0
Methoxychlor (µg/L) 2006-13 96 0 0 0 0 0 0 0
Parathion (µg/L) 2006-13 96 0 0 0 0 0 0 0
Total PCBs (µg/L) 2006-13 96 0 0 0 0 0 0 0
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1.1.4 Effluent and Biosolids Flow Data
Effluent and WAS flow data for the study period was obtained from the Burwood WWTW. A summary
of flow data for the period July 2011 to May 2013 is provided in Table 1.4 (courtesy of Hunter
Water) and Figure 1.3.
Table 1.4 Rainfall, effluent and WAS flow data for the study period (July 2011 - May 2013)
Date
Rainfall (mm)
Secondary Flow (ML)
1
By-Pass Flow (ML)
2
Total Flow (ML)
Biosolids (ML)
3
July 2011 238.2 2068.14 777.24 2845.38 71.66
Aug 2011 47.8 1775.64 0 1775.64 87.73
Sep 2011 136.0 1731.62 205.9 1937.52 82.86
Oct 2011 161.4 1966.85 301.27 2268.12 94.93
Nov 2011 184.5 2004.51 465.58 2470.09 86.71
Dec 2011 110.8 1825.98 6.37 1832.35 92.83
Jan 2012 53.6 1481.64 22.32 1503.96 93.38
Feb 2012 336.7 2296.60 485.42 2782.02 89.47
Mar 2012 188.0 2083.66 403.74 2487.40 96.36
Apr 2012 174.0 1889.04 306.14 2195.18 88.98
May 2012 26.2 1470.51 0 1470.51 94.01
Jun 2012 188.0 2255.16 373.09 2628.25 95.01
Jul 2012 83.5 1839.45 24.17 1863.62 86.77
Aug 2012 71.0 1704.78 62.22 1767.00 93.44
Sep 2012 16.7 1305.15 0 1305.15 87.82
Oct 2012 13.5 1257.72 0 1257.72 76.17
Nov 2012 44.6 1201.80 0 1201.80 86.92
Dec 2012 114.2 1375.59 52.98 1428.57 98.06
Jan 2013 229.0 1488.58 322.25 1810.83 99.86
Feb 2013 175.0 1855.55 397.11 2252.66 87.39
Mar 2013 241.0 1954.00 629.58 2583.58 112.08
Apr 2013 94.5 1702.77 116.92 1819.69 102.98
May 2013 60.0 1538.14 55.7 1593.84 95.64
1 Secondary Flow is total secondary treated flow through the plant (i.e. Total volume of screened and degritted sewage into
secondary plant over a 24 hour period from 12 midnight and discharged to ocean).
2 By-Pass Flow is total volume of screened and degritted sewage which bypasses the secondary plant over a 24 hour period
from 12 midnight and is discharged to ocean
3 Biosolids is the Volume of Waste Activated Sludge pumped from the clarifier underflow over a 24 hour period from 12
midnight and is discharged to ocean.
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Figure 1.3 Burwood Beach flow data for the study period (July 2011 - May 2013).
1.1.5 Dilution Modeling / Dispersion Characteristics
Consulting Environmental Engineers (CEE 2007) calculated a predicted initial dilution for the Burwood
effluent outfall, assuming a discharge rate of 43 ML/d and all duckbill valves in operation. The model
predicted a typical dilution of 219:1 for the effluent field. Allowing for the reduction in dilution due to
the orientation of the diffuser ports parallel to the currents, initial dilution is expected to be in the range
of 180:1 to 220:1. The Water Research Lab (WRL 2007) also carried out field tests of effluent dilution
using rhodamine dye. The dilution of the surface field showed a typical dilution of 185:1. WRL (2007)
reported that the average near-field dilution was 207:1 and the 95th percentile minimum dilution was
78:1. CEE (2010) therefore considers it reasonable to base the environmental risk assessment of the
effects of effluent discharge on an effluent plume near the ocean surface with an initial dilution in the
range of 100:1 to 200:1.
The dilution of a combined biosolids and effluent discharge through the biosolids diffuser was also
calculated (CEE 2007). The CEE model predicted a typical dilution of 475:1 for discharged biosolids
if they rose to the ocean surface, or about 250:1 if trapped by stratification at mid-depth (CEE 2007).
The WRL hydrodynamic computer model showed a median dilution of 300:1, with a minimum dilution
of 100:1 when strong stratification decreases the rise and dilution of the small biosolids plumes, and a
maximum dilution at times of strong currents exceeding 1,000:1 (WRL 2007). The WRL model also
showed the biosolids plume is often trapped well below the surface by the natural stratification of the
ocean water column. WRL field tests of the biosolids plume, with dilution measured using rhodamine
dye, showed a typical dilution of 841:1. WRL reported that the average near-field dilution of the
biosolids plume was 268:1 and the 95th percentile minimum dilution was 205:1, for a submerged
plume (WRL 2007). Based on these results, it is considered reasonable to base the assessment of
the effects of biosolids discharge on two conditions; surface plume with an initial dilution of 300:1 and
submerged plume with an initial dilution of 200:1 (CEE 2010). WRL (1999) modelled the biosolids
plume at 10 m depth and showed that the centre of the plume, at about 10 m depth, the dilution
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achieved is between 200:1 and 1,000:1. At a distance of 200 m from the diffuser, the dilution
exceeds 1,000:1 and increases further with distance travelled. The diluted biosolids extends to the
south of the diffuser, but would be indistinguishable except by the sensitive techniques used in the
field studies. Based on the field tests and dilution modelling undertaken by WRL (1999; 2007) and
CEE (2007), the following mixing zones (Table 1.5) were determined for reporting purposes.
Table 1.5 Classification of zones based on prior effluent dilution modelling.
Distance from Diffuser Zones
< 50 m outfall impact zone outfall impact
> 50 - 100 m
mixing zone
nearfield mixing zone
> 100 - 200 m midfield mixing zone
> 200 - 2,000 m farfield mixing zone
> 2,000 m reference zone reference
1.2 Burwood Beach Marine Environmental Assessment Program
A number of monitoring programs and studies have previously been undertaken to assess the impact
of treated effluent and biosolids discharge on the marine environment at Burwood Beach (e.g. NSW
Environment Protection Authority (NSW EPA) 1994, 1996; The Ecology Lab 1996, 1998; Australian
Water Technologies (AWT) 1996, 1998, 200, 2003; Sinclair Knight Merz (SKM) 1999, 2000; Ecotox
Services Australasia (ESA) 2001, 2005; BioAnalysis 2006; Andrew-Priestley 2011; Andrew-Priestley
et al. 2012). While providing a wealth of data on the marine environment here, it is considered that
these previous studies have not effectively assessed the spatial extent and ecological significance of
the outfalls impact (Consulting Environmental Engineers (CEE) 2010). The aim of the Burwood
Beach Marine Environmental Assessment Program (MEAP) was to establish the impact footprint of
the existing outfall, establish the gradient of impact with distance to the edge of the outfall and predict
the footprint of future discharges.
The Burwood Beach Water Quality Study aimed to address some of the perceived knowledge gaps
by assessing both the spatial and temporal trends of the effluent and biosolids discharges on local
water quality along the effluent and biosolids dispersion pathway, as a function of distance from the
outfall.
1.2.1 Initial Consultation
Prior to commencement of the Burwood Beach MEAP, details of the proposed sampling program and
survey methodology were discussed with Hunter Water, CEE and the NSW EPA (then the Office of
Environment and Heritage (OEH) on 10 October 2011. This initial consultation was undertaken to
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ensure that the proposed MEAP was adequate in addressing the requirements of both the Client
(Hunter Water) and the Regulator (NSW EPA). Water quality parameters to be sampled were
discussed and agreed on. During this meeting, any concerns with the proposed sampling program
were raised and where required the methodology was subsequently altered accordingly.
1.3 Study Area
Burwood Beach is located in Newcastle, on the Hunter Coast of New South Wales (NSW). It lies to
the south of Merewether Beach and to the north of Dudley Beach (Figure 1.1). The seabed in the
vicinity of the outfall consists of small areas of low profile patchy rocky reef, which is subject to strong
wave action and periodic sand movement, interspersed between large areas of soft sediment (sandy)
habitat. These low profile reefs extend to approximately 1 m above the sand. Water depth is
approximately 22 m at the outfall diffuser. Fine mobile sandy sediments occur in the gutters and low-
lying seabed between reef patches. Extensive sandy beaches with intertidal rocky reef habitats occur
along the shoreline adjacent to the outfall.
1.4 Scope of Work / Study Objectives
The Burwood Beach Water Quality Study aimed to characterise the extent of potential impacts to
water quality in the receiving environment from effluent and biosolids discharges, and to define near,
mid and farfield impacts of the plume. Dilution and dispersion characteristics of the effluent and
biosolids discharges were considered in the sampling design.
The primary objectives of the water quality monitoring program were to:
Measure the physicochemistry and concentrations of nutrients, chlorophyll a and faecal
indicators in the receiving environment, at a range of distances from the outfall, to assess the
gradient of potential impacts;
Compare data with relevant guidelines to identify compliance (where applicable). This includes
the Australian and New Zealand Environment and Conservation Council (ANZECC)
Guidelines for Fresh and Marine Water Quality (2000), the New South Wales Environmental
Protection Authority (NSW EPA) Marine Water Quality Guidelines (2000) and the National
Health and Medical Research Council (NHMRC) Guidelines for Managing Risks in
Recreational Waters (2008); and
Measure the footprint of impact on the receiving environment.
1.4.1 Null Hypothesis
The null hypothesis for this study was:
There is no significant difference in the concentration of physicochemical parameters,
nutrients, chlorophyll a or faecal indicators at water quality sampling sites with increasing
distance from the outfalls diffuser.
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1.5 Review of Previous Studies
1.5.1 Burwood Beach WWTW Water Quality Studies
No previous water quality sampling programs have been undertaken to specifically assess the impact
of the Burwood Beach outfall on water quality in the local marine environment. However, Beachwatch
data is collected regularly from nearby beaches. Beachwatch was established in 1989 in response to
community concerns about the impact of sewage pollution on human health and the environment at
Sydney's ocean beaches. Beachwatch provides regular information on water quality to enable people
to make informed decisions about where and when to swim. A total of 127 swimming locations are
monitored in the Sydney, Hunter and Illawarra regions, with a further 129 sites monitored in
partnership with local councils along the NSW coast (NSW Government 2013). Daily bulletins,
monthly and annual reports for all NSW beaches monitored in the program can be obtained from
http://www.environment.nsw.gov.au/beachapp/default.aspx (NSW Government 2013).
Beaches nearby to Burwood Beach that are monitored by Beachwatch for faecal indicators of faecal
contamination (i.e. enterococci) include Bar, Merewether, Burwood North and Burwood South. During
2011- 2012 and 2012- 2013, these beaches were generally graded as suitable for swimming most of
the time but noted that the waters may be susceptible to sources of faecal contamination. These
results show that enterococci levels increase slightly with increasing rainfall. It was outlined that
enterococci levels often exceed the safe swimming limit after rainfall at Bar Beach (after 10 mm) and
Merewether Beach (after 20 mm). For Burwood North and Burwood South, it was outlined that
enterococci levels occasionally exceed the safe swimming limit after 10 mm or more of rainfall.
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2 METHODS
2.1 Sampling Sites
Thirty-two water quality sampling sites were selected in a regularly spaced radial arrangement around
the Burwood Beach outfall diffusers, out to a distance of 2 km (i.e. reference locations). The location
of sampling sites took into account the location of the diffusers, prevailing hydrodynamic conditions in
the area and plume characteristics as determined using a series of aerial photographs
(www.nearmap.com 2011).
Twenty-eight sites were located within 500 m of the diffusers and four reference sites were located at
2 km from the diffusers, in approximately northeast and southwest directions (see Figures 2.1 and
2.2) outside the zone of influence of the diffusers. The distance of reference sites from the diffusers
was considered appropriate based on dilution modelling undertaken by WRL (1999, 2007) and CEE
(2007) (refer to Section 1.1.4).
Each water quality sampling site was allocated a site name and region identification (ID) according to
its distance and direction from the diffusers. Sampling site names, GPS co-ordinates (latitude and
longitude), distance and direction from the diffusers are provided in Table 2.1.
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Figure 2.1 Water quality sampling sites.
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Figure 2.2 Water quality sampling sites close to the Burwood Beach diffusers.
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Table 2.1 Location of sampling sites including distance and direction from the diffuser.
Site Name Distance from Diffuser (m)
Direction Latitude (S)
(WGS84) Longitude (E)
(WGS84)
WQ 1 0 m DIF 32º58.104' 151º45.118'
WQ 2 0 m DIF 32º58.151' 151º45.119'
WQ 3 0 m DIF 32º58.219' 151º45.121'
WQ 4 0 m DIF 32º58.247' 151º45.159'
WQ 5 30 m N 32º58.088' 151º45.119'
WQ 6 30 m E 32º58.192' 151º45.138'
WQ 7 30 m S 32º58.257' 151º45.174'
WQ 8 30 m W 32º58.226' 151º45.099'
WQ 1B 100 m S 32º58.304' 151º45.202'
WQ 9 100 m N 32º58.005' 151º45.119'
WQ 10 100 m E 32º58.159' 151º45.182'
WQ 11 100 m E 32º58.212' 151º45.208'
WQ 12 100 m E 32º58.026' 151º45.222'
WQ 13 100 m S 32º58.301' 151º45.156'
WQ 14 100 m S 32º58.284' 151º45.087'
WQ 15 100 m W 32º58.221' 151º45.054'
WQ 16 100 m W 32º58.142' 151º45.055'
WQ 2B 250 m S 32º58.350' 151º45.232'
WQ 17 250 m N 32º57.969' 151º45.124'
WQ 18 250 m E 32º58.088' 151º45.278'
WQ 19 250 m E 32º58.213' 151º45.315'
WQ 20 250 m E 32º58.031' 151º45.301'
WQ 21 250 m S 32º58.378' 151º45.199'
WQ 22 250 m S 32º58.362' 151º45.054'
WQ 23 250 m W 32º58.239' 151º44.958'
WQ 24 250 m W 32º58.067' 151º44.964'
WQ 3B 500 m S 32º58.444' 151º45.340'
WQ 25 500 m E 32º57.991' 151º45.041'
WQ 26 500 m E 32º58.392' 151º45.043'
WQ 27 500 m S 32º58.489' 151º44.998'
WQ 28 500 m W 32º57.969' 151º44.084'
WQ 29 2 km REFNE 32º57.232' 151º45.878'
WQ 30 2 km REFNE 32º57.637' 151º46.277'
WQ 31 2 km REFSW 32º59.278' 151º44.762'
WQ 32 2 km REFSW 32º59.115' 151º44.037'
N.B. Sites located on the diffuser are allocated to the direction code of ‘DIF’. The reference sites to the north-
east and south-west are labelled ‘REFNE’ and ‘REFSW’ respectively.
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2.2 Temporal Assessment
Eight water quality sampling events were undertaken between July 2011 and April 2013. The majority
of water sampling events were required to be undertaken over a period of two consecutive days to
allow for all sites and parameters to be sampled. All odd numbered sites were sampled on the first
day and even numbered sites on the second day (if not completed on the first day) to ensure that no
one distance or direction was favoured on either day. Sampling events occurred quarterly, with the
timing of sampling heavily influenced by oceanic and weather conditions, due to the coastal and
exposed nature of the Burwood Beach location. For safety and logistical reasons no sampling was
undertaken in swells greater than 2 m maximum. The dates, tidal conditions and wind conditions for
each of the water quality surveys are provided in Table 2.2 below.
Table 2.2 Conditions for each water quality survey.
Survey Sampling
period Date
Tide time
Tide height
Tide time
Tide height
Main Tidal Cycle
Tidal Range (+/- one
day)
Avg Wind
Speed & Dir 9am
(km-1
)
Avg Wind
Speed & Dir 3pm (km
-1)
1 Jul 2011 18/07/11 10:28 1.44 m 1600 0.59 m Ebb - 11 W 13 WSW
1 Jul 2011 19/07/11 11:06 1.44 m 1643 0.63 m Ebb - 15 WSW 22 W
2 Oct 2011 12/10/11 08:11 1.64 m 1423 0.42 m Ebb Spring 11 N 30 SSE
2 Oct 2011 13/10/11 08:43 1.67 m 1500 0.40 m Ebb Spring 20 ESE 22 E
3 Feb 2012 13/02/12 06:15 0.48 m 1215 1.50 m Flood - 15 SSW 24 SE
3 Feb 2012 14/02/12 07:21 0.54 m 1315 1.35 m Flood Neap 11 NW 24 SSE
4 Apr 2012 23/04/12 09:32 1.43 m 1509 0.60 m Ebb - 11 NW 15 NW
5 Jun 2012 27/06/12 07:41 0.47 m 1415 1.55 m Flood Neap - 22 E
5 Jun 2012 28/06/12 08:33 0.49 m 1515 1.63 m Flood Neap - 11 S
6 Oct 2012 15/10/12 07:41 1.79 m 1354 0.24 m Ebb Spring 22 NW 30 ENE
6 Oct 2012 16/10/12 08:26 1.88 m 1445 0.19 m Ebb Spring 24 NW 20 ENE
7 Feb 2013 05/02/13 09:59 0.57 m 1552 1.25 m Flood - 13 SSW 22 ESE
7 Feb 2013 06/02/13 11:14 0.48 m 1709 1.29 m Flood - 9 S 20 E
8 Apr 2013 02/04/13 07:13 0.46 m 1316 1.34 m Flood - 11 WNW 19 SSE
2.2.1 Rainfall Prior to Sampling
Rainfall influences the composition of the final treated effluent and can affect WWTW processing in
terms of the process performance and effluent quality, in particular the removal of particles from
effluent and biosolids (Wilén et al. 2006). Rainfall data for each sampling month is presented below in
Figure 2.3. Yellow stars have been used to show the water quality sampling days for each month
relative to the rainfall measured for that month.
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Figure 2.3 Rainfall data for the sampling month. Sampling days are indicated by yellow stars.
July 2011
October 2011
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Figure 2.3 (Continued) Rainfall data for the sampling month. Sampling days are indicated by
yellow stars.
February 2012
April 2012
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Figure 2.3 (Continued) Rainfall data for the sampling month. Sampling days are indicated by
yellow stars.
April 2012 June 2012 June 2012
October 2012
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Figure 2.3 (Continued) Rainfall data for the sampling month. Sampling days are indicated by
yellow stars.
April 2013
February 2013
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2.3 Sampling Methods
Water quality sampling was undertaken from a 6.4 m aluminium vessel skippered by Sandy Bottom
Boat Charters, Maryville, NSW.
Samples were collected from two depths at each sampling site; one at the surface (i.e. approximately
1 m below surface) and one at mid-water (i.e. half the total water depth as measured by the boat
depth sounder).
2.3.1 In-situ Physicochemical Water Quality Measurements
In-situ field measurements of physicochemical parameters were taken at the surface and mid-water
using a multi-parameter hand held water quality meter (Figure 2.4). Physicochemical parameters
initially measured at each sampling site were those agreed on by Hunter Water and the NSW EPA
during initial consultation and included water clarity (measured with a Secchi-disc), temperature,
electrical conductivity and turbidity (Table 2.3). However, after the first two events of sampling
WorleyParsons recommended that dissolved oxygen and pH were also measured for future sampling
events as these parameters are regulated under the ANZECC (2000) Guidelines. Subsequently, from
February 2012 onwards, dissolved oxygen and pH were also recorded in-situ.
The measured results of some parameters during some sampling events was unrealistic, based on
scientific knowledge that for marine waters these values are not standard, suggesting likely
instrument error. These values were hence excluded from the analysis but have been highlighted in
the raw results which are attached in Appendix 2.
In particular, the measurements of turbidity during the first three sampling events were suspected to
be inaccurate due to continuous problems with the turbidity sensor. Inaccurate readings can occur if
the probe is not calibrated properly or the turbidity sensor is failing. The probe had been calibrated
and serviced prior to each sampling event but after the third sampling event the sensor failed and
stopped reporting turbidity. The results of the first three sampling events were on a much higher
scale (i.e. up to 50 NTU) and were highly variable compared to the ensuing sampling events. Without
existing baseline levels for this region, identifying this issue was difficult as elevated and variable
readings are not uncommon for coastal zones. Upon subsequent review of the data, the first three
sampling events of turbidity data were removed from the data set. For the following five sampling
events, a new turbidity sensor was calibrated and tested against a turbidity standard (50 NTU) to
ensure that it had been calibrated correctly and provided accurate results.
2.3.2 Water Quality Sampling
A total of 64 water column samples were collected during each sampling event to test for nutrients
(ammonia, organic nitrogen, nitrites + nitrates, dissolved inorganic nitrogen, total nitrogen and total
phosphorus), faecal indicators (enterococci and faecal coliforms) and chlorophyll a (i.e. 32 sites x 2
depths). All water samples were collected using a 6.2 L Beta Water Sampler (Figure 2.4). Sample
bottles were supplied and certified for use by the analytical laboratory for each type of analyses
tested. All water samples were collected by directly decanting into their respective sample bottles,
which were then capped and stored on ice in the dark for transport. All water samples were non-
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filtered water collected directly from the Beta Water Sampler with one exception. Water samples
analysed for dissolved inorganic nitrogen were filtered through a 0.45 µm Sartorius filter in the field
prior to analysis. A chain of custody (COC) form accompanied all samples and denoted that samples
were delivered and a sample receipt notification (SRN) ensured samples were analysed within their
representative holding times (see Appendix 1 for an example). All samples were analysed by a
NATA accredited laboratory experienced in marine water analysis; Australian Laboratory Services
Environmental (ALS Environmental). Analysis is accredited for compliance with ISO/IEC 17025. A
list of all analytical parameters tested, laboratory level of reporting (LOR) and guideline values
(ANZECC 2000 / NSW EPA) are provided in Table 2.3.
Figure 2.4 Water sampling equipment (left: Beta Water Sampler; right: multi probe meter).
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Table 2.3 Analytical parameters showing their respective LOR and guideline values.
Analytical Parameter Limit of Reporting
(LOR)
Guideline Guideline reference
In-situ physico-chemical
Secchi-disc depth 0.5 m 1.6 m NSW EPA (2000); ANZECC (2000)
Turbidity 0.1 NTU 6 NTU ANZECC (2000)
Temperature 0.01 °C 15-35 °C NSW EPA (2000)
Electrical Conductivity 0.01 mS/cm None defined
Salinity 0.01 ppt None defined
Dissolved Oxygen mg/L None defined (in mg/L) 6
pH 0.1 8 - 8.4 ANZECC (2000)
Nutrients
Organic Nitrogen as N 5 0.01 mg/L None defined
Ammonia as N 0.005 mg/L 0.02 mg/L
0.5 mg/L7
ANZECC (2000)
ANZECC (2000)
Nitrite + Nitrate (NOx) 0.002 mg/L 0.025 mg/L ANZECC (2000)
Dissolved Inorganic Nitrogen (NH3 + NOx)
3 0.005 mg/L None defined
Total Nitrogen as N 4, 5
0.01 mg/L 0.12 mg/L
NSW EPA (2000); ANZECC (2000)
Total Phosphorus as P 0.005 mg/L 0.025 mg/L NSW EPA (2000); ANZECC (2000)
Chlorophyll a 1 0.5 mg/m
3 (i.e. 0.5
µg/L) 1 mg/m
3 ANZECC (2000)
Thermotolerant Faecal Coliforms 2, 9
1 CFU/100 mL 50% of values ≤150 CFU/100 mL
ANZECC (2000)
Enterococci 2, 8
1 CFU/100 mL 95th percentile of values ≤40 CFU/100 mL
NHMRC (2008)
1 Note that an LOR of 1 mg/m
3 was used for chlorophyll a for the first two sampling events, as per the original agreement
between WorleyParsons, the analytical laboratory and Hunter Water. This LOR was subsequently changed to 0.5 mg/m3.
2 Note that for turbid water samples the analytical laboratory advised that the LOR for microbial samples may need to increase
to 2 CFU / 100 ml. This would be based on visual inspection at the laboratory and cannot be based on any predetermined turbidity value.
3 Dissolved parameters (i.e. dissolved inorganic nitrogen) required field filtering.
4 Note that total nitrogen is calculated by the laboratory as a separate analysis and is not determined by calculation (i.e. may
not always equal the sum of nitrogen components as provided in the data).
5 Note that an LOR of 0.05 mg/L
was used for organic nitrogen and total nitrogen for the first two sampling events, this LOR was
subsequently changed to 0.01 mg/L in later sampling rounds.
6 ANZECC Guideline for dissolved oxygen is 90 to 110 % saturation; however dissolved oxygen was measured in mg/L in this
study.
7 Note this refers to ANZECC (2000) default trigger value for ammonia for 99% level of protection of species in marine waters.
8 Note that ANZECC refers to NHMRC 2008 “Guidelines for Managing Risks in Recreational Waters”. These NHMRC Guidelines recommend a 95 % enterococci limit of < 40 cfu/100 mL as this value is below the NOAEL in most epidemiological studies and the AFRI would be negligible.
9 Note that Faecal coliforms are considered by the NHMRC as an unsuitable regulatory parameter but still form part of NSW Water Quality Guidelines with the limit being 50 % < 150 cfu/100 mL.
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2.4 Quality Assurance / Quality Control
Quality assurance and quality control (QA/QC) procedures employed by staff working in the field are
listed below:
One blank, replicate and duplicate sample for each chemistry parameter was taken for each
day of sampling.
All field survey staff were appropriately trained in the water sampling techniques used (i.e.
use of the hand held multi-probe and Beta Water Sampler).
Field staff wore disposable nitrile gloves at all times during water sampling to prevent
contamination of water samples. Gloves were changed between sampling sites and depths
at each site.
Quality assurance and quality control (QA/QC) procedures employed by the analytical laboratory
(ALS Environmental) are listed below:
The analytical procedures used by ALS Environmental have been developed from established
internationally recognised procedures such as those published by the United States
Environment Protection Agency (USEPA), American Public Health Association (APHA),
Australian Standard (AS) and National Environment Protection Measures (NEPM).
Laboratory QA/QC was undertaken in accordance with ALS standards. A Quality Control
(QC) Report was generated for every sampling event containing the following information:
o Laboratory Duplicate (DUP) Report; Relative Percentage Difference (RPD) and
Acceptance Limits.
o Method Blank (MB) and Laboratory Control Spike (LCS) Report; Recovery and
Acceptance Limits.
o Matrix Spike (MS) Report; Recovery and Acceptance Limits.
2.5 Data Management
Field survey sheets were completed for each sampling site and field data was entered and stored in a
single electronic database. Preliminary data summaries (spread sheets) were prepared following
receipt of results from the laboratory. Appendix 2 provides a summary of all raw field data.
All data received from the field and laboratory were reviewed and subject to standard checks on the
quality of the data (e.g. through review of laboratory QA/QC) to identify anomalies.
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2.6 Data Analysis
2.6.1 Summary Statistics
Summary statistics of results including the mean, standard deviation, median, minimum and
maximum values were calculated for each sampling event. Individual value plots were used as the
main graphical summary tool to examine individual water quality parameters. These graphs are a
useful representation of data because they show all of the data as well as information about the
geographical location of each sample. Data were plotted by both distance and direction of the site
relative to the diffuser and by depth of sample (surface or mid-water). The applicable water quality
guidelines and associated LOR for each parameter were also plotted on the graphs for ease of
reference.
Where laboratory results were found to be less than the LOR, then half the LOR was used as the
nominal concentration to allow for comparison (as agreed during initial consultation with NSW EPA
and Hunter Water and recommended in ANZECC 2000). A table was also produced which
summarises the number and percentage of samples in each zone that exceeded the water quality
guidelines.
2.6.2 Comparison to Water Quality Guidelines
As requested by the NSW EPA during initial consultation, the water quality objectives in this study
were required to address aquatic ecosystem health and primary contact recreation (i.e. swimming,
diving and surfing) for NSW marine waters.
Water quality results have been compared to the respective guideline levels (as outlined in Table 2.3)
for these objectives taken from:
NSW EPA (2000) - NSW Marine Water Quality Objectives for the Hunter and Central Coast
(http://www.environment.nsw.gov.au/water/mwqo/index.htm);
ANZECC (2000) Guidelines for Fresh and Marine Water Quality (Table 3.3.2: Default
trigger values for slightly to moderately disturbed marine ecosystems in South-eastern
Australia) (http://www.environment.gov.au/water/publications/quality/nwqms-guidelines-4-
vol1.html); and
NHMRC (2008) - Guidelines for Managing Risks in Recreational Waters.
(http://www.nhmrc.gov.au/guidelines/publications/eh38).
The study site is classified as a marine and estuarine ecosystem based upon classifications outlined
in ANZECC (2000). ANZECC (2000) notes that the development of indicators for marine and
estuarine ecosystems is not as developed as for freshwater ecosystems, due to the lack of
understanding of the processes and structure and the high spatial and temporal variability associated
with marine ecosystems.
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In the current study, parameters, including temperature, turbidity, ammonia, nitrites + nitrates, total
nitrogen, total phosphorus, enterococci, faecal coliforms and chlorophyll a, were compared to
available guideline levels. Secchi disk depth was deemed to be unreliable and was not compared
with the guideline level (see further information in discussion, Section 4.1). Although there is a
guideline available for dissolved oxygen, this is in different units to what was measured in this study
and hence could not be directly compared (i.e. guideline is in % saturation compared to mg/L which
was measured in this study) and was not deemed suitable to translate the data to %.
The ANZECC (2000) guidelines suggest that comparisons are made using median values from at
least five replicate samples. For chemical analyses, this is very costly and not standard practice
therefore comparison of individual values was done. This enabled a higher resolution for patterns of
potential guideline trigger values, both spatially and temporally. However, for chemistry
measurements this method could have resulted in a lower number of values above trigger levels in
the case where there are outlier values.
It should be noted that the guideline value for Secchi-disc depth of 1.6 m is taken from ANZECC
(2000) and is suggested to be important to protect the visual clarity of waters used for swimming in
recreational waters. The guideline was intended as a horizontal water clarity measure using a black
disc but in this study vertical Secchi-disc depth using a black and white disc has been used as a
surrogate. Previous work suggests that these two measures are likely to be highly correlated (Steel
and Neuhausser 2002; Montes-Hugo et al. 2003).
2.6.3 Trigger Index
The trigger index provides a single value to represent the mean frequency and magnitude of various
parameters that exceeded a water quality guideline across site. Similar to the application of water
quality guidelines, the trigger index provides a benchmark to detect possible impacts and to ensure
that environmental values are protected. The application of a trigger index in this program is designed
to provide an overview of the frequency and magnitude that any chemistry results are exceeding the
water quality guideline.
The water quality guidelines outlined in Table 2.3 for nutrient, chlorophyll a and faecal indicators were
used to create the trigger index. Where there is a result for the trigger index, this represents value/s
that has exceeded the guideline for that site. The higher the trigger index, the higher the frequency
and/or magnitude of values that exceeded the guideline value.
The index resulted in high scores for:
1. Sites or depth classes that contained a high number of values that exceeded the triggers (as a
proportion of total samples at that distance);
2. High magnitude of trigger values (based on the guideline level); or
3. High magnitude of trigger values that had a high frequency.
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The trigger index is outlined in Equations 1 to 3 below.
Equation 1. Summary for trigger index for a given distance.
distance Magnitude of exceedance Frequency of exceedanceIndex
Equation 2. Conceptual framework for trigger index calculation for a given distance.
distance
Sum values exceeding the guidelines no. samples exceeding
Guideline value no. samples exceeding total no. samplesIndex
Equation 3. Trigger index for a given distance expressed mathematically.
1
distance
distanceGV
n
i
i EX
EX
EXN
IndexN N
Where:
Indexdistance = the resultant index value for a given distance from the outfall.
EXi = value of result that exceeds guideline level.
GV = guideline value.
NEX = number of samples exceeding the guideline at that distance.
Ndistance = number of samples taken at that distance.
2.6.4 Multivariate Analysis
Multivariate analysis was done in PRIMER 6 (Clarke and Gorley 2006) with the Permanova+ add on
(Anderson et al. 2008) and represents analysis and modelling of the multivariate suite of nutrients
(i.e. ammonia, organic nitrogen, nitrites + nitrates, dissolved inorganic nitrogen, total nitrogen and
total phosphorus), chlorophyll a, faecal indicators (enterococci and faecal coliforms).
Physicochemical parameters were excluded from the multivariate analysis because the homogeneity
of results did not assist with the assessment of variability due to the outfall.
For multivariate analyses, the data is first transformed to achieve similar distribution among data. A
similarity matrix was then created using the Gower metric. A similarity matrix is a matrix of scores
whereby each score represents the similarity between each pairwise comparison of data points. This
quantitative measure is well suited to dealing with data on different scales containing few zero values.
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The multivariate water quality dataset was analysed using distance based linear modelling (DISTLM)
and distance based redundancy analysis (dbRDA). DISTLM is similar to a regression but on a
multivariate dataset (i.e. the similarity matrix) while a dbRDA plot is a visual model that is used to
represent (i.e. illustrate) the results of DISTLM analysis.
Explanatory variables for the analysis were either temporal (sample date, sample event, season and
sampling year), spatial (distance from the outfall, direction from the outfall and depth at sample site)
or environmental (rainfall in the preceding 3, 5, and 7 days). These variables were first inspected for
skewness and kurtosis using draftsman plots. Distance from the outfall was the only variable that was
not normally distributed and was transformed using Log (10 + V) to achieve normal distribution.
A model selection procedure called BEST was used to select the models that best explained the
variation in the dataset. Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC)
were found to best explain the variation in the data and were chosen to represent the dataset. A
dbRDA plot constrained by the model variables was created to illustrate the fitted model.
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3 RESULTS
Water quality data are presented as summaries by water quality parameters across sampling events.
Graphical summaries are also used prior to multivariate analysis.
3.1 Data Summaries
3.1.1 Sampling Event
The following tables (Table 3.1 – 3.8) provide summary of the results for the physicochemistry,
nutrients, chlorophyll a and faecal indicators for all sites complied by sampling event. The summaries
are based on the edited dataset with outlier values removed as highlighted in Appendix 2. These
tables are a summary of the data across all sampling sites. Although the water quality guidelines
(NSW EPA 2000; ANZECC 2000 and NHMRC 2008) are provided in the table, these values should
not be directly compared to the guidelines, as the summary is representative of pooled data across all
32 sampling sites (i.e. including the outfall, mixing zone and reference sites).
It should be noted that the guideline value for Secchi disc depth of 1.6 m is taken from ANZECC
(2000) and is suggested to be important to protect the visual clarity of waters used for swimming in
recreational waters. The guideline was intended as a horizontal water clarity measure using a black
disc but in this study vertical Secchi disc depth using a black and white disc has been used as a
surrogate. Previous work suggests that these two measures are likely to be highly correlated (Steel
and Neuhausser 2002; Montes-Hugo et al. 2003).
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Table 3.1 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in July 2011, data pooled across sites.
PARAMETER N MEDIAN MEAN STDEV MIN MAX Guideline Value
Surface samples
Secchi Disc Depth (m) 27 2 2 1 1 5 1.61
Turbidity (NTU) 29 * * * * * 61
Temperature (ºC) 29 17.27 17.30 0.12 17.14 17.61 15-352
Conductivity (field; mS/cm) 29 5.51 5.51 0.01 5.49 5.53 None
Ammonia as N (mg/L) 29 0.027 0.030 0.026 0.003 0.081 0.021
Organic Nitrogen as N (mg/L) 29 0.05 0.10 0.09 0.05 0.40 None
Nitrite + Nitrate as N (mg/L) 29 0.080 0.080 0.004 0.074 0.088 0.0251
Inorganic Nitrogen as N (mg/L) 29 0.040 0.038 0.010 0.005 0.050
None
Total Nitrogen as N (mg/L) 29 0.13 0.13 0.03 0.08 0.19 0.121,2
Total Phosphorus as P (mg/L) 29 0.018 0.018 0.004 0.010 0.026 0.0251,2
Chlorophyll a (mg/m3) 29 1 1 0 1 2 1
1
Enterococci (cfu/100ml) 29 40 76 94 1 370 Median ≤ 403
Faecal Coliforms (cfu/100ml) 29 140 153 147 1 400 95th percentile ≤ 1501
Midwater samples
Turbidity (NTU) 29 * * * * * 61
Temperature (ºC) 29 17.25 17.29 0.14 17.12 17.59 15-352
Conductivity (field; mS/cm) 29 5.51 5.51 0.00 5.50 5.52 None
Ammonia as N (mg/L) 29 0.003 0.011 0.015 0.003 0.056 0.021
Organic Nitrogen as N (mg/L) 29 0.05 0.08 0.08 0.05 0.40 None
Nitrite + Nitrate as N (mg/L) 29 0.080 0.081 0.006 0.072 0.094 0.0251
Inorganic Nitrogen as N (mg/L) 29 0.040 0.042 0.007 0.030 0.050
None
Total Nitrogen as N (mg/L) 29 0.10 0.11 0.02 0.09 0.18 0.121,2
Total Phosphorus as P (mg/L) 29 0.016 0.017 0.006 0.012 0.038 0.0251,2
Chlorophyll a (mg/m3) 29 1 1 0 1 1 1
1
Enterococci (cfu/100ml) 29 4 52 83 1 300 Median ≤ 403
Faecal Coliforms (cfu/100ml) 29 24 83 123 1 440 95th percentile ≤ 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
* These parameters were not obtained due to technical issues with the water quality meter during this sampling round.
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Table 3.2 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in October 2011, data pooled across sites.
PARAMETER N MEDIAN MEAN STDEV MIN MAX Guideline Value1
Surface samples
Secchi Disc Depth (m) 32 4 3 1 2 5 1.61
Turbidity (NTU) 25 * * * * * 61
Temperature (ºC) 25 18.51 18.52 0.15 18.25 18.91 15-352
Conductivity (field; mS/cm) 25 5.44 5.43 0.02 5.39 5.47 None
Ammonia as N (mg/L) 32 0.003 0.005 0.004 0.003 0.019 0.021
Organic Nitrogen as N (mg/L) 32 0.08 0.08 0.03 0.03 0.14 None
Nitrite + Nitrate as N (mg/L) 32 0.001 0.001 0.001 0.001 0.004 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.003 0.005 0.004 0.003 0.019 None
Total Nitrogen as N (mg/L) 32 0.09 0.09 0.03 0.03 0.15 0.121,2
Total Phosphorus as P (mg/L) 32 0.012 0.012 0.004 0.003 0.020 0.0251,2
Chlorophyll a (mg/m3) 32 1 1 0 1 2 1
Enterococci (cfu/100ml) 32 2 3 5 1 29 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 2 7 17 1 74 95th percentile ≤ 1501
Midwater samples
Turbidity (NTU) 25 * * * * * 61
Temperature (ºC) 25 18.50 18.41 0.49 17.70 19.06 15-352
Conductivity (field; mS/cm) 25 5.45 5.45 0.02 5.40 5.49 None
Ammonia as N (mg/L) 32 0.003 0.009 0.018 0.003 0.072 0.021
Organic Nitrogen as N (mg/L) 32 0.07 0.07 0.04 0.03 0.16 None
Nitrite + Nitrate as N (mg/L) 32 0.001 0.001 0.000 0.001 0.003 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.003 0.009 0.019 0.003 0.074 None
Total Nitrogen as N (mg/L) 32 0.08 0.07 0.04 0.03 0.23 0.121,2
Total Phosphorus as P (mg/L) 32 0.010 0.010 0.005 0.003 0.021 0.0251,2
Chlorophyll a (mg/m3) 32 1 1 0 1 2 1
1
Enterococci (cfu/100ml) 32 2 6 12 1 64 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 3 20 41 1 180 95th percentile ≤ 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
* These parameters were not obtained due to technical issues with the water quality meter during this sampling round.
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Table 3.3 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in February 2012, data pooled across sites.
PARAMETER N MEDIAN MEAN STDEV MIN MAX Guideline Value1
Surface samples
Secchi Disc Depth (m) 32 4 4 1 3 5 1.61
Turbidity (NTU) 32 * * * * * 61
Temperature (ºC) 32 22.04 22.04 0.27 21.45 22.51 15-352
Conductivity (field; mS/cm) 32 5.47 5.44 0.05 5.27 5.49 None
Dissolved oxygen (mg/L) 32 7.61 7.56 0.14 7.15 7.71
pH 32 8.08 8.09 0.04 8.00 8.19 8-8.41
Ammonia as N (mg/L) 32 0.003 0.003 0.000 0.003 0.003 0.021
Organic Nitrogen as N (mg/L) 32 0.03 0.03 0.03 0.03 0.20 None
Nitrite + Nitrate as N (mg/L) 32 0.001 0.002 0.002 0.001 0.011 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.003 0.003 0.002 0.003 0.011 None
Total Nitrogen as N (mg/L) 32 0.01 0.01 0.03 0.01 0.20 0.121,2
Total Phosphorus as P (mg/L) 32 0.006 0.007 0.006 0.003 0.036 0.0251,2
Chlorophyll a (mg/m3) 32 0.38 0.44 0.25 0.25 1.0 1
1
Enterococci (cfu/100ml) 32 1 1 2 1 8 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 1 1 3 1 13 95th percentile ≤ 1501
Midwater samples
Turbidity (NTU) 32 * * * * * 61
Temperature (ºC) 32 18.52 18.04 2.01 15.07 21.13 15-352
Conductivity (field; mS/cm) 32 5.52 5.52 0.03 5.42 5.57 None
Dissolved oxygen (mg/L) 32 5.96 6.22 0.99 5.06 9.86
pH 32 * * * * * 8-8.41
Ammonia as N (mg/L) 32 0.006 0.021 0.035 0.003 0.155 0.021
Organic Nitrogen as N (mg/L) 32 0.03 0.03 0.01 0.03 0.07 None
Nitrite + Nitrate as N (mg/L) 32 0.019 0.045 0.051 0.001 0.154 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.029 0.065 0.083 0.003 0.304 None
Total Nitrogen as N (mg/L) 32 0.04 0.07 0.09 0.01 0.34 0.121,2
Total Phosphorus as P (mg/L) 32 0.010 0.014 0.011 0.003 0.045 0.0251,2
Chlorophyll a (mg/m3) 32 0.38 0.44 0.33 0.25 2.0 1
1
Enterococci (cfu/100ml) 32 1 20 47 1 250 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 1 45 75 1 300 95th percentile ≤ 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
* These parameters were not obtained due to technical issues with the water quality meter during this sampling round.
HUNTER WATER
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Table 3.4 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in April 2012, data pooled across sites.
PARAMETER N MEDIAN MEAN STDEV MIN MAX Guideline Value1
Surface samples
Secchi Disc Depth (m) 32 4 4 1 3 6 1.61
Turbidity (NTU) 32 2.4 2.4 0.6 0.9 4.2 61
Temperature (ºC) 32 22.16 22.18 0.11 22.04 22.74 15-352
Conductivity (field; mS/cm) 32 5.48 5.48 0.00 5.46 5.49 None
Dissolved oxygen (mg/L) 32 7.09 7.09 0.09 6.92 7.42
pH 32 8.43 8.42 0.04 8.23 8.47 8-8.41
Ammonia as N (mg/L) 32 0.003 0.003 0.000 0.003 0.003 0.021
Organic Nitrogen as N (mg/L) 32 0.03 0.03 0.03 0.03 0.20 None
Nitrite + Nitrate as N (mg/L) 32 0.001 0.002 0.002 0.001 0.011 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.003 0.003 0.002 0.003 0.011 None
Total Nitrogen as N (mg/L) 32 0.01 0.01 0.03 0.01 0.20 0.121,2
Total Phosphorus as P (mg/L) 32 0.006 0.007 0.006 0.003 0.036 0.0251,2
Chlorophyll a (mg/m3) 32 0.38 0.44 0.25 0.25 1.0 1
1
Enterococci (cfu/100ml) 32 1 1 2 1 8 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 1 1 3 1 13 95th percentile ≤ 1501
Midwater samples
Turbidity (NTU) 32 2.3 2.5 0.8 1.2 5.7 61
Temperature (ºC) 32 21.87 21.90 0.18 21.24 22.48 15-352
Conductivity (field; mS/cm) 32 5.50 5.49 0.02 5.40 5.52 None
Dissolved oxygen (mg/L) 32 6.68 6.65 0.12 6.29 6.82
pH 32 8.44 8.44 0.01 8.40 8.46 8-8.41
Ammonia as N (mg/L) 32 0.003 0.016 0.029 0.003 0.134 0.021
1 Organic Nitrogen as N (mg/L) 32 0.05 0.06 0.05 0.03 0.27 None
Nitrite + Nitrate as N (mg/L) 32 0.005 0.007 0.005 0.001 0.020 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.009 0.021 0.033 0.003 0.154 None
Total Nitrogen as N (mg/L) 32 0.06 0.08 0.07 0.03 0.35 0.121,2
Total Phosphorus as P (mg/L) 32 0.010 0.012 0.011 0.003 0.062 0.0251,2
Chlorophyll a (mg/m3) 32 0.25 0.38 0.20 0.25 1.0 1
1
Enterococci (cfu/100ml) 32 4 16 37 1 190 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 11 46 83 1 400 95th percentile ≤ 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
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Table 3.5 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a measured in June 2012, data pooled across sites.
PARAMETER N MEDIAN MEAN STDEV MIN MAX Guideline
Value1
Surface samples
Secchi Disc Depth (m) 32 3 3 0 2 3 1.61
Turbidity (NTU) 32 1.5 1.7 0.9 0.6 4.6 61
Temperature (ºC) 32 17.00 16.95 0.15 16.60 17.10 15-352
Conductivity (field; mS/cm) 32 * * * * * None
Dissolved oxygen (mg/L) 32 7.50 7.62 0.29 7.30 8.50
pH 32 8.24 8.24 0.01 8.21 8.26 8-8.41
Ammonia as N (mg/L) 32 0.030 0.033 0.027 0.003 0.080 0.021
Organic Nitrogen as N (mg/L) 32 0.09 0.10 0.07 0.03 0.31 None
Nitrite + Nitrate as N (mg/L) 32 0.037 0.037 0.002 0.031 0.044 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.068 0.070 0.028 0.034 0.117 None
Total Nitrogen as N (mg/L) 32 0.15 0.17 0.09 0.02 0.36 0.121,2
Total Phosphorus as P (mg/L) 32 0.017 0.019 0.007 0.008 0.036 0.0251,2
Chlorophyll a mg/m3) 32 0.25 0.25 0.0 0.25 0.25 1
1
Enterococci (cfu/100ml) 32 71 76 65 1 200 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 130 105 83 1 250 95th percentile ≤ 1501
Midwater samples
Turbidity (NTU) 32 1.4 1.4 0.4 0.6 2.7 61
Temperature (ºC) 32 17.00 16.94 0.13 16.50 17.10 15-352
Conductivity (field; MS/cm) 32 * * * * * None
Dissolved oxygen (mg/L) 32 7.75 7.84 0.37 7.50 9.60
pH 32 8.24 8.23 0.01 8.18 8.25 8-8.41
Ammonia as N (mg/L) 32 0.011 0.020 0.031 0.003 0.153 0.021
Organic Nitrogen as N (mg/L) 32 0.06 0.09 0.09 0.03 0.42 None
Nitrite + Nitrate as N (mg/L) 32 0.038 0.038 0.004 0.029 0.052 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.048 0.056 0.032 0.029 0.190 None
Total Nitrogen as N (mg/L) 32 0.10 0.14 0.12 0.01 0.54 0.121,2
Total Phosphorus as P (mg/L) 32 0.014 0.014 0.006 0.003 0.031 0.0251,2
Chlorophyll a (mg/m3) 32 0.25 0.25 0.0 0.25 0.25 1
1
Enterococci (cfu/100ml) 32 14 41 52 1 200 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 34 60 67 1 200 95th percentile ≤ 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
* These parameters were not obtained due to technical issues with the water quality meter during this sampling round.
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Page 40 301020-03413 : 210 FINAL DRAFT : October 2013
Table 3.6 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a
measured in October 2012, data pooled across sites.
PARAMETER N MEDIAN MEAN STDEV MIN MAX Guideline Value1
Surface samples
Secchi Disc Depth (m) 32 3 2 0 2 3 1.61
Turbidity (NTU) 32 1.0 1.0 0.0 1.0 1.0 61
Temperature (ºC) 32 18.25 18.25 0.19 17.70 18.60 15-352
Conductivity (field) (field; mS/cm) 32 * * * * * None
Dissolved oxygen (mg/L) 32 * * * * *
pH 32 8.33 8.32 0.01 8.30 8.34 8-8.41
Ammonia as N (mg/L) 32 0.042 0.041 0.039 0.000 0.111 0.51
Organic Nitrogen as N (mg/L) 32 0.11 0.13 0.08 0.07 0.50 None
Nitrite + Nitrate as N (mg/L) 32 0.002 0.002 0.002 0.000 0.006 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.046 0.043 0.040 0.000 0.115 None
Total Nitrogen as N (mg/L) 32 0.18 0.18 0.10 0.07 0.56 0.121,2
Total Phosphorus as P (mg/L) 32 0.019 0.018 0.012 0.000 0.044 0.0251,2
Chlorophyll a (mg/m3) 32 2.00 1.43 0.99 0.25 3.00 1
1
Enterococci (cfu/100ml) 32 47 77 177 1 1000 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 60 149 170 1 560 95th percentile ≤ 1501
Midwater samples
Turbidity (NTU) 32 1.0 1.0 0.0 1.0 1.0 61
Temperature (ºC) 32 18.00 18.06 0.08 18.00 18.30 15-352
Conductivity (field) (field; mS/cm) 32 * * * * * None
Dissolved oxygen (mg/L) 32 * * * * *
pH 32 8.32 8.32 0.02 8.29 8.37 8-8.41
Ammonia as N (mg/L) 32 0.018 0.021 0.022 0.000 0.090 0.51
Organic Nitrogen as N (mg/L) 32 0.11 0.12 0.04 0.07 0.22 None
Nitrite + Nitrate as N (mg/L) 32 0.001 0.001 0.001 0.000 0.004 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.019 0.022 0.023 0.000 0.092 None
Total Nitrogen as N (mg/L) 32 0.15 0.15 0.05 0.07 0.24 0.121,2
Total Phosphorus as P (mg/L) 32 0.015 0.015 0.007 0.000 0.030 0.0251,2
Chlorophyll a (mg/m3) 32 0.63 1.00 0.86 0.25 3.00 1
1
Enterococci (cfu/100ml) 32 26 30 33 1 150 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 58 99 98 1 270 95th percentile ≤ 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
* These parameters were not obtained due to technical issues with the water quality meter during this sampling round.
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Table 3.7 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a
measured in February 2013, data pooled across sites.
PARAMETER N MEAN STDEV MEDIAN MIN MAX Guideline Value1
Surface samples
Secchi Disc Depth (m) 32 2 0 2 2 3 1.61
Turbidity (NTU) 32 3.9 1.3 3.5 1.9 8.2 61
Temperature (ºC) 32 22.85 0.27 22.80 22.50 23.40 15-352
Conductivity (field; mS/cm) 32 5.65 0.02 5.65 5.61 5.68 None
Dissolved oxygen (mg/L) 32 9.59 0.16 9.56 9.41 10.18
pH 32 8.20 0.04 8.20 8.16 8.34 8-8.41
Ammonia as N (mg/L) 32 0.007 0.009 0.003 0.003 0.044 0.51
Organic Nitrogen as N (mg/L) 32 0.19 0.05 0.18 0.11 0.40 None
Nitrite + Nitrate as N (mg/L) 32 0.003 0.002 0.004 0.001 0.007 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.009 0.011 0.005 0.003 0.051 None
Total Nitrogen as N (mg/L) 32 0.19 0.05 0.19 0.12 0.41 0.121,2
Total Phosphorus as P (mg/L) 32 0.003 0.001 0.003 0.003 0.008 0.0251,2
Chlorophyll a (mg/m3) 32 0.89 0.47 0.80 0.25 2.30 1
1
Enterococci (cfu/100ml) 32 11 22 3 1 95 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 100 244 3 1 1100 95th percentile ≤ 1501
Mid-water samples
Turbidity (NTU) 32 2.8 0.4 2.8 2.0 3.7 61
Temperature (ºC) 32 22.60 0.12 22.60 22.50 22.90 15-352
Conductivity (field; mS/cm) 32 5.67 0.01 5.67 5.65 5.68 None
Dissolved oxygen (mg/L) 32 9.58 0.13 9.58 9.36 9.89
pH 32 8.18 0.03 8.18 8.14 8.24 8-8.41
Ammonia as N (mg/L) 32 0.023 0.029 0.007 0.003 0.121 0.51
Organic Nitrogen as N (mg/L) 32 0.19 0.06 0.19 0.11 0.39 None
Nitrite + Nitrate as N (mg/L) 32 0.005 0.003 0.005 0.001 0.013 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.026 0.032 0.011 0.003 0.134 None
Total Nitrogen as N (mg/L) 32 0.22 0.08 0.20 0.12 0.51 0.121,2
Total Phosphorus as P (mg/L) 32 0.004 0.003 0.003 0.003 0.018 0.0251,2
Chlorophyll a (mg/m3) 32 0.84 0.41 0.85 0.25 1.90 1
1
Enterococci (cfu/100ml) 32 12 18 3 1 59 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 165 302 1 1 1200 95th percentile ≤ 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
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Table 3.8 Summary of physicochemistry, nutrients, faecal indicators and chlorophyll a
measured in April 2013, data pooled across sites.
PARAMETER N MEAN STDEV MEDIAN MIN MAX Guideline Value1
Surface samples
Secchi Disc Depth (m) 32 2 0 2 1 3 1.61
Turbidity (NTU) 32 1.5 1.5 0.9 0.1 5.7 61
Temperature (ºC) 32 22.82 0.22 22.80 22.00 23.20 15-352
Conductivity (field; mS/cm) 32 * * * * * None
Dissolved oxygen (mg/L) 32 6.80 0.47 6.78 5.80 7.73
pH 32 * * * * * 8-8.41
Ammonia as N (mg/L) 32 0.051 0.033 0.061 0.003 0.125 0.51
Organic Nitrogen as N (mg/L) 32 0.16 0.03 0.14 0.11 0.23 None
Nitrite + Nitrate as N (mg/L) 32 0.004 0.007 0.002 0.001 0.039 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.055 0.035 0.062 0.003 0.127 None
Total Nitrogen as N (mg/L) 32 0.21 0.05 0.22 0.12 0.32 0.121,2
Total Phosphorus as P (mg/L) 32 0.007 0.009 0.003 0.003 0.040 0.0251,2
Chlorophyll a (mg/m3) 32 0.58 0.34 0.60 0.25 1.80 1
1
Enterococci (cfu/100ml) 32 102 182 53 1 1000 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 517 1034 250 1 5500 95th percentile ≤ 1501
Mid-water samples
Turbidity (NTU) 32 0.3 0.3 0.2 0.0 1.6 61
Temperature (ºC) 32 22.82 0.08 22.80 22.60 23.00 15-352
Conductivity (field; mS/cm) 32 * * * * * None
Dissolved oxygen (mg/L) 32 6.62 0.46 6.61 5.87 8.52
pH 32 * * * * * 8-8.41
Ammonia as N (mg/L) 32 0.016 0.016 0.013 0.003 0.092 0.51
Organic Nitrogen as N (mg/L) 32 0.17 0.09 0.14 0.12 0.50 None
Nitrite + Nitrate as N (mg/L) 32 0.002 0.001 0.001 0.001 0.004 0.0251
Inorganic Nitrogen as N (mg/L) 32 0.017 0.016 0.014 0.003 0.095 None
Total Nitrogen as N (mg/L) 32 0.19 0.09 0.16 0.13 0.52 0.121,2
Total Phosphorus as P (mg/L) 32 0.003 0.002 0.003 0.003 0.010 0.0251,2
Chlorophyll a (mg/m3)) 32 0.50 0.25 0.50 0.25 1.30 1
1
Enterococci (cfu/100ml) 32 56 79 23 1 380 Median ≤ 403
Faecal Coliforms (cfu/100ml) 32 162 229 88 1 1200 95th percentile ≤ 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
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3.1.2 Zone
The following table (Table 3.9) provides a summary of water quality data by distance from the outfall which is divided into zones (0 m and 30 m- outfall zone,
100 m, 250 m and 500 m- mixing zone, 2 km – reference zone). This table is a summary of the data pooled across all sampling events. The NSW Marine
Water Quality Objectives (NSW EPA), ANZECC (2000) and NHMRC (2008) guideline values are also provided in the table.
Table 3.9 Summary of median and 95th percentile data by zone
Parameter
Median Level 95th
percentile n Guideline Value
outfall mixing zone reference outfall
mixing zone reference outfall
mixing zone reference
Turbidity (NTU) 2.60 2.40 1.45 12.80 7.16 9.79 121 281 52 61
Temperature (oC) 18.44 18.95 20.63 22.90 22.90 23.10 130 306 56 15- 35
Conductivity (mS/cm) 5.50 5.50 5.50 5.67 5.67 5.68 81 186 32 -
Dissolved oxygen (mg/L) 7.49 7.40 7.25 9.62 9.69 9.82 80 200 40 -
pH 8.32 8.28 8.27 8.45 8.45 8.39 64 160 32 8- 8.41
Ammonia as N (mg/L) 0.017 0.003 0.003 0.093 0.060 0.021 134 312 60 11
Organic Nitrogen as N (mg/L) 0.115 0.080 0.080 0.230 0.200 0.282 134 312 60 -
Nitrite + Nitrate as N (mg/L) 0.005 0.003 0.003 0.087 0.079 0.073 134 312 60 0.0251
Inorganic Nitrogen as N (mg/L) 0.031 0.012 0.006 0.127 0.079 0.060 134 312 60 -
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
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Table 3.9 (continued) Summary of median and 95th percentile data by zone
Parameter
Median Level 95th percentile n Guideline
Value outfall mixing zone reference outfall mixing zone reference outfall mixing zone reference
Total Nitrogen as N (mg/L) 0.160 0.100 0.100 0.340 0.220 0.353 134 312 60 0.121,2
Total Phosphorus as P (mg/L) 0.013 0.009 0.008 0.033 0.020 0.017 134 312 60 0.0251, 2
Chlorophyll a (mg/m3) 0.50 0.50 0.25 2.00 1.75 0.80 134 312 60 1
1
Enterococci (CFU/100ml) 26.50 4.00 1.00 180.00 108.00 16.90 134 312 60 95th percentile
< 40 3
Faecal Coliforms (CFU/100ml) 125.00 6.00 0.50 757.00 202.50 54.60 134 312 60 50% of values
< 1501
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
This table shows is a clear overall pattern of decreasing concentrations, with the highest results in the outfall, followed by the mixing zone in comparison to
the reference zone, for the parameters of ammonia, inorganic nitrogen, total nitrogen, total phosphorus, enterococci and faecal coliforms. The median, and
where relevant 95th percentile, results are discussed for each parameter in Section 3.2.
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3.2 Physicochemical Parameters
The following section outlines the physicochemistry results graphed across all distances and sampling events. The results are discussed in the order of:
patterns over sampling events, patterns between zones, and overall median of zones (Table 3.9) followed by comparison to water quality guidelines (where
applicable). As outlined in Section 3.1.2 and Table 3.9, the overall medians by zone were calculated on data which was pooled across all sampling events
and divided into zones (0 m and 30 m- outfall, 100 m, 250 m and 500 m- mixing zone, 2 km – reference).
Figures 3.1- 3.5 are based on the edited dataset with outlier values removed as highlighted in Appendix 2.
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Figure 3.1 provides Secchi disc depth data for each sampling event. The results during the first four sampling events were higher and more variable. There
is a pattern in the sampling events, July 2011 to April 2012, of increasing Secchi disc depth with distance from the outfall. This pattern is not the same for the
final four sampling events, where Secchi disc measurements were generally homogenous between sites (ranging from 1 to 2). There is no water quality
guideline available for Secchi disc.
Figure 3.1 Secchi disc depth.
200050
025
010
0300
6
5
4
3
2
1
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010
030020
00500
250
100300
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010
030020
00500
250
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030020
00500
250
100300
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0300
July 2011
Distance from diffuser (log m)
Se
cch
i Dis
c D
ep
th (
m)
October 2011 February 2012 April 2012 June 2012 October 2012 February 2013 April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction
24
22
20
18
16
200050
0250
100300
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22
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010
030020
00500
250
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0250
100300
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0100300
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010
030020
00500
250
100300
Surface, July 2011
Distance from diffuser (log m)
Te
mp
era
ture
(C
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction
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Turbidity data are presented in Figure 3.2. The data from the first three months of sampling was removed as many of the values obtained during this event
were thought to have been erroneous due to equipment malfunction. The results were similar during the first three sampling events. During February 2013
and April 2013, turbidity in the surface waters was higher and more variable. Overall, median values were similar among zones with 2.60 NTU in the outfall
zone, 2.40 NTU in the mixing zone and 1.45 NTU in the reference zone (Table 3.9). In February 2013, there were some values that exceeded the ANZECC
(2000) water quality guideline of 6 NTU. This included one measurement of 8.2 NTU at 250 m and two measurements of 6.2 NTU at 500 m.
Figure 3.2 Turbidity.
30
20
10
0
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0300
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0
200050
0250
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010
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0250
100300
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0250
100300
200050
025
0100300
200050
025
010
0300
Surface, July 2011
Distance from diffuser (log m)
Tu
rbid
ity
(N
TU
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction24
22
20
18
16
200050
0250
100300
24
22
20
18
16
200050
025
010
030020
00500
250
100300
200050
025
010
0300200050
0250
100300
200050
025
0100300
200050
025
010
030020
00500
250
100300
Surface, July 2011
Distance from diffuser (log m)
Te
mp
era
ture
(C
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction30
20
10
0
200050
025
010
0300
30
20
10
0
200050
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100300
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025
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0250
100300
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0250
100300
200050
025
0100300
200050
025
010
0300
Surface, July 2011
Distance from diffuser (log m)
Tu
rbid
ity
(N
TU
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction
WQ Guideline
3
2
1
0
200050
025
0100300
3
2
1
0
200050
025
010
0300200050
025
010
0300200050
0250
100300
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
0250
100300
Surface, July 2011
Distance from diffuser (log m)
Ch
loro
ph
yll
a (
mg
/L)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR (2011) = 1 mg/L LOR (2012 & 2013) = 0.5 mg/L WQ Guideline = 1 mg/L
WQ Guideline
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 48 301020-03413 : 210 FINAL DRAFT : October 2013
Temperature data is provided in Figure 3.3. There are consistent seasonal patterns with similar profiles seen over the sampling years. In the warmer
summer months of February and April mean water temperatures range from 21.5 to 23.4°C in surface waters and from 15.1 to 23°C in mid-waters (due to
colder and variable results in February 2012). The mid-water results in February 2012 were highly variable and colder in comparison to February 2013.
February 2012 coincides with a reported cyclonic eddy upwelling of deeper and cooler waters from the continental shelf into coastal waters in the region from
Sydney to Bryon Bay (IMOS 2012). In the cooler winter months (i.e. June, July and October during both sampling years) mean water temperatures were
similar between the surface and mid-waters and ranged from 16.5 to 19.1°C. Overall, water temperature was cooler in the outfall and mixing zones in
comparison to the reference zone (with medians of 18.44°C in the outfall zone, 18.95°C in the mixing zone and 20.63°C in the reference zone) (Table 3.9).
With the exception of measurements in the mid-water during February 2012, all values fell within the NSW EPA (2000) guideline of 15- 35°C.
24
22
20
18
16
200050
0250
100300
24
22
20
18
16
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
0100300
200050
025
010
030020
00500
250
100300
Surface, July 2011
Distance from diffuser (log m)
Te
mp
era
ture
(C
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction
Figure 3.3 Temperature.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 49 301020-03413 : 210 FINAL DRAFT : October 2013
Conductivity (electrical conductivity), which is shown in Figure 3.4, was found to be homogenous across sites and between the sampling events of July 2011
and April 2012. The data results were generally similar between sampling events, the highest levels were recorded in the February 2013 sampling event
(ranging from 5.27 to 5.9 mS/cm). Release of effluent from the WWTW provides a source of freshwater which may mean that the receiving environment could
be expected to show a decrease in conductivity and salinity. However there were no patterns with distance from the outfall with median values of 5.5 mS/cm
in all zones (Table 3.9). There is no water quality guideline available for conductivity.
Figure 3.4 Conductivity.
6.0
5.5
5.0
200050
025
0100300
6.0
5.5
5.0
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
0250
100300
200050
0250
100300
200050
025
010
0300200050
0250
100300
Surface, July 2011
Distance from diffuser (log m)
Co
nd
ucti
vit
y (
mS
/cm
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction6.0
5.5
5.0
200050
025
0100300
6.0
5.5
5.0
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
0250
100300
200050
0250
100300
200050
025
010
0300200050
0250
100300
Surface, July 2011
Distance from diffuser (log m)
Co
nd
ucti
vit
y (
mS
/cm
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction6.0
5.5
5.0
200050
025
0100300
6.0
5.5
5.0
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
0250
100300
200050
0250
100300
200050
025
010
0300200050
0250
100300
Surface, July 2011
Distance from diffuser (log m)
Co
nd
ucti
vit
y (
mS
/cm
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction6.0
5.5
5.0
200050
025
0100300
6.0
5.5
5.0
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
0250
100300
200050
0250
100300
200050
025
010
0300200050
0250
100300
Surface, July 2011
Distance from diffuser (log m)
Co
nd
ucti
vit
y (
mS
/cm
)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
DIF
N
E
S
W
REFNE
REFSW
Direction
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 50 301020-03413 : 210 FINAL DRAFT : October 2013
Dissolved oxygen (DO) data is shown in Figure 3.5. Measurements of this variable were taken from the February 2012 sampling event onwards at both the
surface and mid-water. Within sampling events, the data is generally homogenous between sites and depths. Between February 2012 and June 2012, the
levels of DO were similar at surface waters ranging from 6.92 to 8.5 mg/L, but were more variable at mid-waters ranging from 5.06 to 9.86 mg/L. This is likely
due to the shelf intrusion reported in February 2012. Concentrations of DO were highest during February 2013 (ranging from 9.36 L to 10.18 mg/L). Overall,
there was no pattern with distance from the outfall with medians of 7.49 mg/L in the outfall zone, 7.40 mg/L in the mixing zone and 7.25 mg/L in the reference
zone (Table 3.9). The water quality guideline available for dissolved oxygen is in % saturation whereas mg/L was measured in this study, hence it was not
compared.
Figure 3.5 Dissolved oxygen.
12.5
10.0
7.5
5.0
2000500250100300
12.5
10.0
7.5
5.0
2000500250100300 2000500250100300 2000500250100300 2000500250100300 2000500250100300
Surface, February 2012
Distance from diffuser (log m)
Dis
so
lve
d o
xy
ge
n (
mg
/L)
Surface, A pril 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, A pril 2013
Midwater, February 2012 Midwater, A pril 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, A pril 2013
DIF
N
E
S
W
REFNE
REFSW
Direction12.5
10.0
7.5
5.0
2000500250100300
12.5
10.0
7.5
5.0
2000500250100300 2000500250100300 2000500250100300 2000500250100300 2000500250100300
Surface, February 2012
Distance from diffuser (log m)
Dis
so
lve
d o
xy
ge
n (
mg
/L)
Surface, A pril 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, A pril 2013
Midwater, February 2012 Midwater, A pril 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, A pril 2013
DIF
N
E
S
W
REFNE
REFSW
Direction
12.5
10.0
7.5
5.0
2000500250100300
12.5
10.0
7.5
5.0
2000500250100300 2000500250100300 2000500250100300 2000500250100300 2000500250100300
Surface, February 2012
Distance from diffuser (log m)
Dis
so
lve
d o
xy
ge
n (
mg
/L)
Surface, A pril 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, A pril 2013
Midwater, February 2012 Midwater, A pril 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, A pril 2013
DIF
N
E
S
W
REFNE
REFSW
Direction
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 51 301020-03413 : 210 FINAL DRAFT : October 2013
pH data are presented in Figure 3.6. Data were collected from the April 2012 sampling event onwards, at both the surface and mid-water. Within sampling
events, pH was homogenous between sites and there was no relationship seen with distance from the outfall. All sampling events had similar pH levels.
Overall, the median values were similar between zones with medians of 8.32 in the outfall zone, 8.28 in the mixing zone and 8.27 in the reference zone
(Table 3.9). There is no water quality guideline available for pH.
Figure 3.6 pH.
9.6
9.2
8.8
8.4
8.0
2000500250100300
9.6
9.2
8.8
8.4
8.0
2000500250100300 2000500250100300 2000500250100300 2000500250100300 2000500250100300
Surface, February 2012
Distance from diffuser (log m)
pH
Surface, A pril 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, A pril 2013
Midwater, February 2012 Midwater, A pril 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, A pril 2013
DIF
N
E
S
W
REFNE
REFSW
Direction9.6
9.2
8.8
8.4
8.0
2000500250100300
9.6
9.2
8.8
8.4
8.0
2000500250100300 2000500250100300 2000500250100300 2000500250100300 2000500250100300
Surface, February 2012
Distance from diffuser (log m)
pH
Surface, A pril 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, A pril 2013
Midwater, February 2012 Midwater, A pril 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, A pril 2013
DIF
N
E
S
W
REFNE
REFSW
Direction9.6
9.2
8.8
8.4
8.0
2000500250100300
9.6
9.2
8.8
8.4
8.0
2000500250100300 2000500250100300 2000500250100300 2000500250100300 2000500250100300
Surface, February 2012
Distance from diffuser (log m)
pH
Surface, A pril 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, A pril 2013
Midwater, February 2012 Midwater, A pril 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, A pril 2013
DIF
N
E
S
W
REFNE
REFSW
Direction
WQ Guideline = 8.0- 8.4
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 52 301020-03413 : 210 FINAL DRAFT : October 2013
3.3 Nutrients, chlorophyll a and faecal indicators
The following section outlines the nutrient, chlorophyll a and faecal indicator results graphed across
all distances and sampling events. The results are discussed in the order of: patterns over sampling
events, patterns between zones, and overall median of zones (Table 3.9) followed by comparison to
water quality guidelines (where applicable). As outlined in Section 3.1.2 and Table 3.9, the overall
medians by zone were calculated on data which was pooled across all sampling events and divided
into zones (0 m and 30 m- outfall, 100 m, 250 m and 500 m- mixing zone, 2 km – reference).
3.3.1 Nitrogen Forms
Nitrogen was measured in each water sample in the following forms:
Ammonia as N (NH4, LOR = 0.005 mg/L)
Organic nitrogen as N (LOR = 0.01 mg/L)
Nitrites + nitrates (NO2- + NO3
-, LOR = 0.002 mg/L)
Dissolved inorganic nitrogen (DIN) (LOR = 0.005 mg/L)
Total nitrogen (LOR = 0.01 mg/L)
Where samples were below the LOR, concentrations were reported as half the LOR, which is how
data below the LOR is typically treated by ANZECC (2000) for site comparisons.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 53 301020-03413 : 210 FINAL DRAFT : October 2013
Ammonia as N is shown in Figure 3.7. High levels of ammonia were detected in July 2011, June 2012, October 2012 and April 2013. Ammonia values
decreased with distance from the outfall during July 2011, June 2013, October 2012 and April 2013. Overall, ammonia levels were highest at the outfall with
a median of 0.017 mg/L in the outfall zone, followed by 0.003 mg/L in both the mixing zone and reference zone (Table 3.9). The ammonia concentration
exceeded the guideline of 0.02 mg/L in all sampling events, and occurred in both surface and mid-water samples for the majority of events (i.e. July 2011,
June 2012, October 2012, February 2013 and April 2013).
0.16
0.12
0.08
0.04
0.00
200050
025
0100300
0.16
0.12
0.08
0.04
0.00
200050
025
010
0300200050
0250
100300
200050
0250
100300
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
025
0100300
Surface, July 2011
Distance from diffuser (log m)
Am
mo
nia
as N
(m
g/
L)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 0.005 mg/L WQ Guideline = 0.02 mg/L
Figure 3.7 Ammonia as N.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 54 301020-03413 : 210 FINAL DRAFT : October 2013
Organic nitrogen as N is presented in Figure 3.8. Concentrations of organic nitrogen did not appear to vary seasonally and for most sampling events were
similar around the outfall and at reference sites. For both the June 2012 and October 2012 events there is some evidence to suggest a trend of diminishing
organic nitrogen values with increasing distance from the diffuser, regardless of direction. Overall, organic nitrogen decreased with distance with medians of
0.115 mg/L in the outfall zone, 0.080 mg/L in the mixing zone and reference zones (Table 3.9). There is no defined water quality guideline for organic
nitrogen.
0.48
0.36
0.24
0.12
0.00
200050
025
010
0300
0.48
0.36
0.24
0.12
0.00
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
0250
100300
200050
0250
100300
200050
0250
100300
Surface, July 2011
Distance from diffuser (log m)
Org
an
ic N
itro
ge
n a
s N
(m
g/
L)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 0.05 No WQ Guideline defined
Figure 3.8 Organic Nitrogen as N.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 55 301020-03413 : 210 FINAL DRAFT : October 2013
Nitrites + nitrates are shown in Figure 3.9. High levels of nitrites + nitrates occurred in three of the eight sampling events (July 2011, February 2012 and
June 2012). Both winter sampling events (July 2011 and June 2012) had high levels of nitrites + nitrates which appear to be seasonal, with homogenous
findings across all sites. Similar levels were observed at all sample sites. During February 2012, there was a similar profile of variability as was seen in the
water temperature findings, and this event coincided with an upwelling event. Values were highest during July 2011 (i.e. ranging from 0.072 mg/L to 0.094
mg/L). Overall, values were slightly higher in the outfall zone with a median of 0.005 mg/L compared to a median of 0.003 mg/L for both the mixing zone and
reference zone (Table 3.9). ANZECC (2000) guidelines were exceeded at all or some sampling sites in July 2011 (100 % of values), February 2012 (22% of
values), June 2012 (100 % of values) and April 2013 (2% of values).
0.16
0.12
0.08
0.04
0.00
200050
025
0100300
0.16
0.12
0.08
0.04
0.00
200050
025
010
0300200050
0250
100300
200050
0250
100300
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
025
0100300
Surface, July 2011
Distance from diffuser (log m)
Nit
rite
+ N
itra
te a
s N
(m
g/
L)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 0.002 mg/L WQ Guideline = 0.025 mg/L
Figure 3.9 Nitrite + Nitrate as N.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 56 301020-03413 : 210 FINAL DRAFT : October 2013
Dissolved inorganic nitrogen (DIN) as N is shown in Figure 3.10. The results show patterns of decreasing DIN with distance from the outfall in surface and
mid-water samples during the June 2012, October 2012, February 2013 and April 2013 sampling events, and in mid-water samples for the February 2012
event. No strong trends were observed for the other sampling events. Overall, there was a pattern of decreasing concentrations with distance from the
outfall with medians of 0.031 mg/L in the outfall zone, 0.012 mg/L in the mixing zone followed by 0.006 mg/L in the reference zone (Table 3.9). There is no
defined water quality guideline for inorganic nitrogen.
0.3
0.2
0.1
0.0
200050
0250
100300
0.3
0.2
0.1
0.0
200050
025
010
030020
00500
250
100300
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
0250
100300
200050
0250
100300
Surface, July 2011
Distance from diffuser (log m)
Ino
rga
nic
Nit
rog
en
as N
(m
g/
L)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 0.005 No WQ Guideline defined
Figure 3.10 Inorganic Nitrogen as N.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 57 301020-03413 : 210 FINAL DRAFT : October 2013
Figure 3.11 shows total nitrogen as N. During July 2011 and from June 2012 onwards, there was a pattern of decreasing total nitrogen with distance from
the outfall. Values were highest during June 2012, ranging from 0.04 to 0.54 mg/L at the outfall and 30 m, 0.01 to 0.34 mg/L at 100 - 500 m sites and 0.04 to
0.36 mg/L at the reference sites. During the June 2012 and February 2013 sampling events, there were values at the reference sites that were similar to
those measured at the outfall. During all sampling events, there were values that exceeded the ANZECC (2000) water quality guideline of 0.12 mg/L. There
was a higher frequency and magnitude of values that exceeded the guideline during the last four sampling events; June 2012, October 2012, February 2013
and April 2013. Overall, there was a median of 0.16 mg/L in the outfall zone, followed by 0.10 mg/L in the mixing zone and 0.10 in the reference zone (Table
3.9). The high proportion of values (across all zones) that exceed the ANZECC (2000) water quality guide of 0.12 mg/L suggests the need for further
investigations to develop a site specific trigger value for total nitrogen.
0.60
0.45
0.30
0.15
0.00
200050
025
0100300
0.60
0.45
0.30
0.15
0.00
200050
025
010
0300200050
0250
100300
200050
0250
100300
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
025
0100300
Surface, July 2011
Distance from diffuser (log m)
To
tal N
itro
ge
n a
s N
(m
g/
L)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
0.05
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
0.05
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 0.05 mg/L WQ Guideline = 0.12 mg/L
Figure 3.11 Total Nitrogen as N.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 58 301020-03413 : 210 FINAL DRAFT : October 2013
3.3.2 Total Phosphorus
Total phosphorus, a measure of all forms of phosphorus (orthophosphate, condensed phosphate and organic phosphate) was measured at all water quality
sites (Figure 3.12). . The highest values of total phosphorus were detected in June 2012, October 2012 and April 2013. There was a clear relationship with
distance from the outfall, with phosphorus being higher at sites that were closest to the outfall and this pattern was most apparent during October 2012.
Overall, there were medians of 0.013 mg/L for the outfall zone, 0.009 mg/L for the mixing zone and 0.008 mg/L for the reference zone (Table 3.9).
Concentrations of total phosphorus exceeded the ANZECC (2000) guideline value of 0.025 mg/L during six of the eight sampling events, with all but one of
those values detected within 500 m of the outfall.
0.060
0.045
0.030
0.015
0.000
200050
025
010
0300
0.060
0.045
0.030
0.015
0.000
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
0300
Surface, July 2011
Distance from diffuser (log m)
To
tal P
ho
sp
ho
rus a
s P
(m
g/
L)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 0.005 mg/L WQ Guideline = 0.025 mg/L
Figure 3.12 Total Phosphorus as P.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 59 301020-03413 : 210 FINAL DRAFT : October 2013
3.3.3 Chlorophyll a
Chlorophyll a data are shown in Figure 3.13. Where samples were below the LOR, they were reported as half the LOR (1 mg/L in 2011 and 0.5 mg/L in 2012
and 2013). The highest results were measured during October 2012 (which ranged from < LOR to 3 mg/m3) and February 2013 (< LOR - 2.3 mg/ m
3).
During October 2012 and February 2013, values were elevated of a similar magnitude out to 500 m of the outfall. However, overall there wasn’t a strong
pattern with distance with a median of 0.50 mg/m3 for both the outfall and mixing zone and 0.25 mg/m
3 for the reference zone (Table 3.9). The ANZECC
(2000) guideline of 1 mg/L for chlorophyll a was exceeded the most during October 2012 and February 2013 in 45% and 31% of samples, respectively, with
all of these occurring within 500 m of the outfall. There were also occasional (i.e. 1.5% to 5% of total samples) exceeded values seen at 500 m or at
reference sites during most of the sampling events (i.e. during July 2011, October 2011, February 2012, April 2012 and April 2013).
Figure 3.13 Chlorophyll a.
3
2
1
0
200050
025
010
0300
3
2
1
0
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
0300
Surface, July 2011
Distance from diffuser (log m)
Ch
loro
ph
yll
a (
mg
/L)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR (2011) = 1 mg/L LOR (2012 & 2013) = 0.5 mg/L WQ Guideline = 1 mg/L
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3.3.4 Faecal Indicators
Enterococci data are presented in Figure 3.14. The July 2011, June 2012, February 2013 and April 2013 sampling events had the highest levels of
enterococci values within 500 m of the outfall. There were no apparent seasonal patterns but levels were generally highest during the last four sampling
events. There was a pattern of decreasing enterococci concentrations with distance from the outfall. At times, concentrations of enterococci were also
elevated at the reference sites. Overall, there was a median of 26.50 CFU/ 100 mL in the outfall zone, 4 CFU/ 100 mL in the mixing zone and 1 CFU/ 100 mL
in the reference zone (Table 3.9). The NHRMC (2008) guideline is ≤ 40 CFU/ 100 mL for the 95th percentile of data. Overall, this guideline was exceeded in
the outfall and the mixing zone with 95th percentiles of 180 CFU/ 100 mL and 108 CFU/100 mL, respectively (Table 3.9). In comparison, the 95th percentile
of the reference zone was 16.90 CFU/ 100 mL.
Figure 3.14 Enterococci.
1000
100
10
1
200050
025
010
0300
1000
100
10
1
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
0300
Surface, July 2011
Distance from diffuser (log m)
En
tero
co
cci (C
FU/
10
0m
l; L
OG
sca
le)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 1 CFU/100ml WQ Guideline = 40 CFU/100ml
1000
100
10
1
200050
025
010
0300
1000
100
10
1
200050
025
010
030020
00500
250
100300
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025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
0300
Surface, July 2011
Distance from diffuser (log m)
En
tero
co
cci (C
FU/
10
0m
l; L
OG
sca
le)
Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 1 CFU/100ml WQ Guideline = 35 CFU/100ml
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Faecal coliforms are shown in Figure 3.15. A similar pattern was found to enterococci, where the highest values were measured in July 2011, June 2012,
February 2013 and April 2013 and within 500 m of the outfall. The magnitude and frequency of elevated faecal coliform values was similar at the outfall in
comparison to sites within the mixing zone (100 - 500 m). The highest value recorded was 5500 CFU/100 mL at the outfall during April 2013. Similarly to
enterococci, water quality guideline values were exceeded during all sampling events with higher levels frequently found at outfall sites relative to reference
sites. Overall, there were medians of 125 CFU/ 100 mL in the outfall zone, 6 CFU/ 100 mL in the mixing zone and 0.5 CFU/ 100 mL in the reference zone
(Table 3.9). The ANZECC guideline is that 50% of samples are ≤ 150 CFU/ 100 mL and overall the median of the outfall zone exceeded this guideline.
10000
1000
100
10
1
0.1
200050
025
0100300
10000
1000
100
10
1
0.1
200050
025
010
030020
00500
250
100300
200050
0250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
Surface, July 2011
Distance from diffuser (log m)
Fae
ca
l C
olif
orm
s (
CFU
/1
00
ml;
LO
G s
ca
le) Surface, October 2011 Surface, February 2012 Surface, April 2012 Surface, June 2012 Surface, October 2012 Surface, February 2013 Surface, April 2013
LOR
WQ Guideline
Midwater, July 2011 Midwater, October 2011 Midwater, February 2012 Midwater, April 2012 Midwater, June 2012 Midwater, October 2012 Midwater, February 2013 Midwater, April 2013
LOR
WQ Guideline
DIF
N
E
S
W
REFNE
REFSW
Direction
LOR = 1 CFU/100ml WQ Guideline = 150 CFU/100ml
Figure 3.15 Faecal coliforms.
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3.3.5 Summary of Signature Parameters by Zone
A separate analysis of the water quality data by zone was undertaken by CEE and the full report is
provided in Appendix 3. The water quality dataset was pooled over sampling events and was divided
into four zones for an overall comparison and assessment of the impact footprints.
This analysis suggests that ammonia, organic nitrogen, total nitrogen, total phosphorus, enterococci
and faecal coliforms have a clear and consistent footprint which extended to 100- 500 m from the
outfall depending on the parameter.
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3.4 Comparison of Results to Water Quality Guidelines
3.4.1 Summary
The water quality parameters, results and percentage of samples that exceeded guidelines along with
the available NSW EPA and ANZECC (2000) water quality guidelines, are presented in Table 3.10.
The overall number (index) of values that exceed water quality guidelines by sample distance from
the outfall is shown in Figure 3.16. Please note that this table includes all sites sampled during this
study (i.e. due to the patterns that were observed with distance from the outfall if the reference sites
were removed then the percentages would be higher for many of the parameters). Graphical
representations of the trigger index for each parameter tested are provided in Figures 3.16 to 3.23.
The individual results for enterococci and faecal coliforms are directly compared to the guideline in
Table 3.10, although it should be noted that these guidelines refer to percentages or percentiles of
data (i.e. enterococci is 95th percentile < guideline and faecal coliforms is 50% of values < guideline).
A summary per sampling event to highlight guideline values that were exceeded follows;
July 2011 – Pattern of impact evident for ammonia, and total nitrogen, enterococci, and faecal
coliforms in terms of how they exceeded the guideline. Samples exceeding the water quality
guideline levels were found in a predominantly southerly and westerly direction but some to the
east of the outfall as well. All samples at both depths returned values of nitrate + nitrite that
exceeded the guideline level. This same pattern was evident in winter 2012.
October 2011 – Many of the parameters tested were uniformly below the LOR. High ammonia
concentrations (above water quality guidelines) were observed between 0 m and 250 m from the
outfall. There was a similar pattern of total nitrogen and chlorophyll a levels around the outfall,
mixing zone and reference sites. One outfall site had high levels of enterococci and faecal
coliforms in the sample taken at mid-water.
February 2012 – Water quality values were exceeded for ammonia, total nitrogen, total
phosphorus, enterococci and faecal coliforms within 250 m from the outfall. This sampling event
coincided with a reported cold water upwelling along the coast from Sydney to Bryon Bay. Mid-
water samples were colder and had more variable water temperature and nitrites + nitrates
results in comparison to the other February sampling event.
April 2012 – There were fewer samples that exceeded the guidelines during this sampling
event in comparison to other sampling events. Water quality values were exceeded for total
nitrogen, total phosphorus and chlorophyll a, mainly at reference sites. Enterococci and faecal
coliform values exceeded water quality guidelines exclusively within 250 m of the outfall.
June 2012 – There were a large number of oxidised nitrogen values that were found to exceed
the guidelines across all spatial sites at both the surface and mid-water. There were patterns of
decreasing concentrations of ammonia, total nitrogen, total phosphorus, enterococci and faecal
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coliforms, with distance from the outfall. These parameters also had a higher proportion and
magnitude of values that exceeded the guidelines around the outfall sites which diminished with
distance from the outfall.
October 2012 – This sampling event showed similar patterns to the previous event in June
2012. Ammonia, total nitrogen, total phosphorus, chlorophyll a, enterococci and faecal coliforms
frequently exceeded the respective water quality guidelines around the outfall with decreasing
concentrations with distance from the outfall. There were no parameters that exceeded the
guidelines at reference sites.
February 2013 – There were high levels of total nitrogen which exceeded the guidelines but
with a similar magnitude and frequency across all sites. Strong gradients with distance from the
outfall were apparent for ammonia, enterococci, faecal coliforms and chlorophyll a. Chlorophyll a
was also elevated around the outfall, showing a pattern of decreased values with distance from
the outfall, although the levels were lower in comparison to the October 2012 sampling event.
April 2013 – Total nitrogen exceeded guideline levels across all sites. Ammonia, enterococci
and faecal coliforms all exhibited patterns of decreasing trigger values with distance from the
outfall, but of a lower magnitude to that observed during October 2012 and January 2013. Levels
of chlorophyll a were lower in comparison to the October 2012 and January 2013 sampling events
and similar to all other sampling events.
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Table 3.10 Number and percentage of samples that exceeded the associated water quality guideline values.
July 2011
Parameter WQ Guideline
Outfall Mixing Zone Reference
N %
Exceeded N
%
Exceeded N
%
Exceeded
Ammonia as N (mg/L) 0.021 22 50 32 47 4 0
Nitrate + Nitrite (mg/L) 0.0251 22 100 32 100 4 100
Total Nitrogen as N (mg/L) 0.121, 2 22 55 32 44 4 0
Total Phosphorus as P (mg/L) 0.0251,2 22 9 32 3 4 0
Chlorophyll a (mg/m3) 11 22 5 32 0 4 0
Enterococci (CFU/100ml) 95th percentile ≤ 403 22 55 32 47 4 0
Faecal Coliforms (CFU/100ml) 50% of values ≤1503 22 55 32 41 4 0
October 2011
Parameter WQ Guideline
Outfall Mixing Zone Reference
N %
Exceeded N
%
Exceeded N
%
Exceeded
Ammonia as N (mg/L) 0.021 16 13 40 5 8 0
Nitrate + Nitrite (mg/L) 0.0251 16 0 40 0 8 0
Total Nitrogen as N (mg/L) 0.121, 2 16 25 40 8 8 13
Total Phosphorus as P (mg/L) 0.0251,2 16 0 40 0 8 0
Chlorophyll a (mg/m3) 11 16 6 40 5 8 13
Enterococci (CFU/100ml) 95th percentile ≤ 403 16 6 40 0 8 0
Faecal Coliforms (CFU/100ml) 50% of values ≤1503 16 6 40 0 8 0
February 2012
Parameter WQ Guideline
Outfall Mixing Zone Reference
N %
Exceeded N
%
Exceeded N
%
Exceeded
Ammonia as N (mg/L) 0.021 16 31 48 10 8 0
Nitrate + Nitrite (mg/L) 0.0251 16 31 48 15 8 25
Total Nitrogen as N (mg/L) 0.121, 2 16 31 48 10 8 0
Total Phosphorus as P (mg/L) 0.0251,2 16 25 48 2 8 0
Chlorophyll a (mg/m3) 11 16 0 48 0 8 13
Enterococci (CFU/100ml) 95th percentile ≤ 403 16 25 48 2 8 0
Faecal Coliforms (CFU/100ml) 50% of values ≤1503 16 19 48 2 8 0
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
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Table 3.10 (continued) Number and percentage of samples that exceeded the associated water quality guideline values.
April 2012
Parameter WQ Guideline
Outfall Mixing Zone Reference
N %
Exceeded N
%
Exceeded N
%
Exceeded
Ammonia as N (mg/L) 0.021 16 6 48 8 8 25
Nitrate + Nitrite (mg/L) 0.0251 16 0 48 0 8 0
Total Nitrogen as N (mg/L) 0.121, 2 16 6 48 4 8 25
Total Phosphorus as P (mg/L) 0.0251,2 16 0 48 2 8 13
Chlorophyll a (mg/m3) 11 16 0 48 0 8 13
Enterococci (CFU/100ml) 95th percentile ≤ 403 16 6 48 4 8 0
Faecal Coliforms (CFU/100ml) 50% of values ≤1503 16 6 48 4 8 0
June 2012
Parameter WQ Guideline
Outfall Mixing Zone Reference
N %
Exceeded N
%
Exceeded N
%
Exceeded
Ammonia as N (mg/L) 0.021 16 69 48 29 8 13
Nitrate + Nitrite (mg/L) 0.0251 16 100 48 83 8 100
Total Nitrogen as N (mg/L) 0.121, 2 16 88 48 38 8 25
Total Phosphorus as P (mg/L) 0.0251,2 16 31 48 6 8 0
Chlorophyll a (mg/m3) 11 16 0 48 0 8 0
Enterococci (CFU/100ml) 95th percentile ≤ 403 16 69 48 38 8 25
Faecal Coliforms (CFU/100ml) 50% of values ≤1503 16 63 48 6 8 0
October 2012
Parameter WQ Guideline
Outfall Mixing Zone Reference
N %
Exceeded N
%
Exceeded N
%
Exceeded
Ammonia as N (mg/L) 0.021 16 94 48 40 8 0
Nitrate + Nitrite (mg/L) 0.0251 16 0 48 0 8 0
Total Nitrogen as N (mg/L) 0.121, 2 16 94 48 46 8 0
Total Phosphorus as P (mg/L) 0.0251,2 16 19 48 13 8 0
Chlorophyll a (mg/m3) 11 16 75 48 35 8 0
Enterococci (CFU/100ml) 95th percentile ≤ 403 16 75 48 35 8 0
Faecal Coliforms (CFU/100ml) 50% of values ≤1503 16 88 48 27 8 0
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
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Table 3.10 (continued) Number and percentage of samples that exceeded the associated water quality guideline values.
February 2013
Parameter WQ Guideline
Outfall Mixing Zone Reference
N %
Exceeded N
%
Exceeded N
%
Exceeded
Ammonia as N (mg/L) 0.021 16 50 48 15 8 0
Nitrate + Nitrite (mg/L) 0.0251 16 0 48 0 8 0
Total Nitrogen as N (mg/L) 0.121, 2 16 94 48 81 8 100
Total Phosphorus as P (mg/L) 0.0251,2 16 0 48 0 8 0
Chlorophyll a (mg/m3) 11 16 38 48 29 8 0
Enterococci (CFU/100ml) 95th percentile ≤ 403 16 19 48 8 8 0
Faecal Coliforms (CFU/100ml) 50% of values ≤1503 16 56 48 10 8 0
April 2013
Parameter WQ Guideline
Outfall Mixing Zone Reference
N %
Exceeded N
%
Exceeded N
%
Exceeded
Ammonia as N (mg/L) 0.021 16 75 48 35 8 13
Nitrate + Nitrite (mg/L) 0.0251 16 0 48 2 8 0
Total Nitrogen as N (mg/L) 0.121, 2 16 100 48 81 8 100
Total Phosphorus as P (mg/L) 0.0251,2 16 13 48 0 8 0
Chlorophyll a (mg/m3) 11 16 0 48 4 8 0
Enterococci (CFU/100ml) 95th percentile ≤ 403 16 81 48 33
8 0
Faecal Coliforms (CFU/100ml) 50% of values ≤1503 16 94 48 29 8 0
1 ANZECC (2000),
2 NSW EPA (2000),
3 NHMRC (2008)
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3.4.2 Trigger Index
Surface and midwater samples were combined for each sampling parameter being compared to the
guidelines (ANZECC 2000; NSW EPA 2000 or NHMRC 2008). The frequency and magnitude of
results that exceeded the guideline levels were plotted by distance from the outfall using a trigger
index. An overview for each parameter is provided in Figure 3.16 and a breakdown of the triggers
index by sampling event is shown in Figures 3.16 to 3.23.
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Figure 3.16 Trigger index values for all parameters by distance from the outfall. Data from all sampling events are combined.
200050
025
010
0300
2.0
1.5
1.0
0.5
0.0
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025
010
030020
00500
250
100300
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025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
Ammonia
Distance (m)
Ex
ce
ed
an
ce
in
de
x
Chlorophyll a Enterococci Faecal Coliforms Nitrite + Nitrate Total Nitrogen Total Phosphorus
200050
025
010
0300
2.0
1.5
1.0
0.5
0.0
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
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025
010
030020
00500
250
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Ammonia
Distance (m)
Ex
ce
ed
an
ce
in
de
x
Chlorophyll a Enterococci Faecal Coliforms Nitrite + Nitrate Total Nitrogen Total Phosphorus
200050
025
010
0300
2.0
1.5
1.0
0.5
0.0
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
100300
Ammonia
Distance (m)
Ex
ce
ed
an
ce
in
de
x
Chlorophyll a Enterococci Faecal Coliforms Nitrite + Nitrate Total Nitrogen Total Phosphorus
200050
025
010
0300
2.0
1.5
1.0
0.5
0.0
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025
010
030020
00500
250
100300
200050
025
010
030020
00500
250
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025
010
030020
00500
250
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Ammonia
Distance (m)
Ex
ce
ed
an
ce
in
de
x
Chlorophyll a Enterococci Faecal Coliforms Nitrite + Nitrate Total Nitrogen Total Phosphorus
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The frequency and magnitude of values that exceeded water quality guidelines for ammonia was greater around the outfall relative to the reference sites
during four of the eight sampling events (June 2011, July 2012, October 2012 and April 2013) (Figure 3.17). At other times there appeared to be a similar but
much smaller effect. At the reference sites, there were few values that exceeded the guidelines for ammonia suggesting that the outfall is responsible for the
localised enrichment of ammonia in the water column.
200050
025
010
0300
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
July 2011
Distance (m)
Ex
ce
ed
an
ce
in
de
x
October 2011 February 2012 April 2012 June 2012 October 2012 February 2013 April 2013
Figure 3.17 Trigger index values for ammonia by distance from the outfall for each sampling event.
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Levels of nitrites + nitrates were above guideline values during three of the eight sampling events (July 2011, February 2012 and June 2012) (Figure 3.18).
All sites in the winter sampling events (July 2011 and June 2012) had values that exceeded guidelines, at all distances, with a similar magnitude and
frequency from the outfall to the reference sites.
200050
025
010
0300
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
July 2011
Distance (m)
Ex
ce
ed
an
ce
in
de
x
October 2011 February 2012 April 2012 June 2012 October 2012 February 2013 April 2013
Figure 3.18 Trigger index values for nitrites + nitrates by distance from the outfall for each sampling event.
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The patterns of values that exceeded water quality guidelines for total nitrogen are similar to those seen for ammonia, suggesting that it is the ammonia
nitrogen component that is driving the high nitrogen values (Figure 3.19). Interestingly the trigger index is comparable for total nitrogen at the reference sites
to the outfall site in February 2013.
200050
025
010
0300
2.5
2.0
1.5
1.0
0.5
0.0
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
July 2011
Distance (m)
Ex
ce
ed
an
ce
in
de
x
October 2011 February 2012 April 2012 June 2012 October 2012 February 2013 April 2013
Figure 3.19 Trigger index values for total nitrogen by distance from the outfall for each sampling event.
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The trigger index results for total phosphorus suggest that effluent discharge may be responsible for some of the higher values of phosphorus, at least some
of the time (Figure 3.20). There was a clear pattern of values that exceeded the guidelines with distance from the outfall during June 2012. Patterns with
distance from the outfall can also be seen during February 2012, October 2012 and April 2013. Results from the other four sampling events do not suggest
an outfall impact.
200050
025
010
0300
0.6
0.5
0.4
0.3
0.2
0.1
0.0
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
July 2011
Distance (m)
Ex
ce
ed
an
ce
in
de
x
October 2011 February 2012 April 2012 June 2012 October 2012 February 2013 April 2013
Figure 3.20 Trigger index values for total phosphorus by distance from the outfall for each sampling event.
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Chlorophyll a exceeded the water quality guidelines during most sampling events (Figure 3.21). Samples from October 2012 and February 2013 show large
and frequent values that exceeded guidelines between 0 - 500 m from the outfall. There were no values at the reference sites that exceeded the guidelines
for chlorophyll a during these events. However, during October 2011, February 2012 and April 2012, there were values that exceeded the guidelines at the
reference sites.
200050
025
010
0300
2.0
1.5
1.0
0.5
0.0
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
July 2011
Distance (m)
Ex
ce
ed
an
ce
in
de
x
October 2011 February 2012 April 2012 June 2012 October 2012 February 2013 April 2013
Figure 3.21 Trigger index values for chlorophyll a by distance from the outfall for each sampling event.
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For some sampling events, there was a pattern evident between enterococci trigger values and distance from the outfall (Figure 3.22). High frequencies and
magnitudes of guideline values that were triggered occurred in four of the eight sampling events. During July 2011, June 2012, October 2012 and April 2013
enterococci trigger indexes were quite high within 500 m of the outfall. Out of all sampling events, there were only two values that triggered above guidelines
that occurred at a reference site and these were both during June 2012. All other trigger values occurred within 500 m of the outfall.
200050
025
010
0300
4
3
2
1
0
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
200050
025
010
0300
July 2011
Distance (m)
Ex
ce
ed
an
ce
in
de
x
October 2011 February 2012 April 2012 June 2012 October 2012 February 2013 April 2013
Figure 3.22 Trigger index values for enterococci by distance from the outfall for each sampling event.
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A detectable outfall impact effect was apparent for faecal coliform results for almost all sampling events (i.e. July 2011, June 2012, October 2012, February
2013 and April 2013) but was much larger in some than others (Figure 3.23). There were no values of faecal coliforms that exceeded the guidelines at any of
the reference sites. Samples from April 2013 contained the highest levels of faecal coliforms.
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October 2011 February 2012 April 2012 June 2012 October 2012 February 2013 April 2013
Figure 3.23 Trigger index values for faecal coliforms by distance from the outfall for each sampling event.
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3.5 Multivariate Data Analysis
3.5.1 Multidimensional Scaling
A similarity matrix of multivariate water quality response data was created using the Gower metric in
PRIMER 6 (Clarke and Gorley 2006). The multidimensional scaling plots (MDS) were plotted
represent modelling of the multivariate suite of nutrients (ammonia, organic nitrogen, nitrites +
nitrates, dissolved inorganic nitrogen and total nitrogen), faecal indicators (enterococci and faecal
coliforms) and chlorophyll a. Physicochemical parameters were not included in the analysis (see
Section 2.6.4).
The multidimensional scaling (MDS) plots are presented in Figures 3.24 to 3.29 and graph the factors
of sample date, sampling event, season and sampling year. The MDS plots are a series of graphs
that group the data by different factors (for each of these graphs the points are in the same positions
but are highlighted in different colours by different factors).
The sample date, sampling event, season and sampling year all appear to contribute to the
organisation of samples in the plots. These results suggest that water quality in this area changes
over time and can be differentiated by temporal scales as short as a single day. When samples on
the MDS plots were coded by distance or direction from the outfall, no obvious grouping of samples
were apparent based on these categories (Figures 3.28 and 3.29).
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Resemblance: S15 Gower
Sample date18/07/2011
19/07/2011
12/10/2011
13/10/2011
13/02/2012
14/02/2012
23/04/2012
27/06/2012
28/06/2012
15/10/2012
16/10/2012
5/02/2013
6/02/2013
2/04/2013
2D Stress: 0.14
Figure 3.24 MDS plot of multivariate water quality response data similarity matrix created
using the Gower metric. Symbols are plotted by sample date.
Resemblance: S15 Gower
Sampling periodJuly 2011
October 2011
February 2012
April 2012
June 2012
October 2012
February 2013
April 2013
2D Stress: 0.14
Figure 3.25 MDS plot of the multivariate water quality response data similarity matrix created
using the Gower metric. Samples are plotted by sampling event.
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Resemblance: S15 Gower
SeasonSpring
Summer
Autumn
Winter
Ammonia Surface
Nitrite + Nitrate Surface
Inorganic Nitrogen Surface
Total Nitrogen Surface
2D Stress: 0.14
Figure 3.26 MDS plot of the multivariate water quality similarity matrix created using the Gower
metric. Samples are plotted by season with influential variables plotted as a vector overlay.
Resemblance: S15 Gower
Sampling Year2011/12
2012/13
2D Stress: 0.14
Figure 3.27 MDS plot of the multivariate water quality similarity matrix created using the Gower
metric. Samples are plotted by sampling year.
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Resemblance: S15 Gower
Distance0
30
100
250
500
2000
2D Stress: 0.14
Figure 3.28 MDS plot of the multivariate water quality similarity matrix created using the Gower
metric. Samples are plotted by distance from the outfall in meters.
Resemblance: S15 Gower
DirectionDIF
N
S
E
W
REFNE
REFSW
2D Stress: 0.14
Figure 3.29 MDS plot of the multivariate water quality similarity matrix created using the Gower
metric. Samples are plotted by direction from the outfall. The category ‘DIF’ includes all sites
located on the outfall. Directional categories include sites between 30 m and 500 m. The
reference sites are indicated by ‘REFNE’ and ‘REFSE’.
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3.5.2 Multivariate Multiple Regression (DISTLM)
A permutational multivariate multiple regression analysis (also known as distance based linear
modelling or DISTLM) was performed on the water quality response data similarity matrix (comprised
of the multivariate suite of nutrients (ammonia, organic nitrogen, nitrites + nitrates, dissolved inorganic
nitrogen and total nitrogen), faecal indicators (enterococci and faecal coliforms) and chlorophyll a.
The aim of the analysis was to determine the combination of explanatory parameters that best
accounted for the variability observed in the dataset. Model selection was performed using the
selection procedure ‘BEST’ and the individual selection criteria Akaike Information Criterion (AIC) and
Bayesian Information Criterion (BIC). The analyses produced a list of the 10 most useful models
according to each selection criteria. The chosen model was ranked within two AIC and BIC points of
the best solution but contained one less variable than the models at the top of each list.
The selected model contained just two of the possible 16 variables. These were ‘sample date’ and
‘distance from diffuser’. Results of sequential tests performed using this model (Table 3.11) show
that ‘sample date’ accounts for 60.8% of the variation observed in the dataset (p-value = 0.001).
When ‘sample date’ is held constant a further 6.5% of the variation can be explained by a sites
distance from the outfall (p = 0.001). The total amount of variation explained by this model was
therefore 67%, which is fairly high for this type of study. It does however suggest that there are other
factors yet to be accounted for which drive local water quality in this area.
Table 3.11 Results of the multivariate multiple regression analysis (DISTLM) applied to the
water quality similarity matrix.
Variable SS (trace) Pseudo-F P-value Proportion Cumulative proportion
Residual df
Sample date 25365 28.601 0.001 0.6087 0.609 239
Distance 2692.2 9.256 0.001 0.0646 0.673 234
The fitted model was chosen using the BEST procedure in DISTLM and explains a total of 67% of the
variability in the dataset. SS (trace) = regression explained sums of squares; Pseudo-F = permutational
test statistic; Proportion = amount of variation explained by each parameter after the previous
parameters have been sequentially fitted; df = degrees of freedom.
Results of the multivariate regression analysis are illustrated by a distance based redundancy
analysis (dbRDA) plot constrained by the variables ‘sample date’ and ‘distance’ (Figures 3.33 to
3.34). These plots tell us that the two dbRDA axes display 75.1% of the fitted variation in the model
and 50% of the total variation in the dataset. That is, this plot is a good representation of the model
and a reasonable representation of the real-world variability in the dataset. Further insight can be
gained by plotting samples according to explanatory variables not included in the model. Observed
patterns can be more easily discerned in this way (relative to the original MDS plots) because
variability due to daily water quality fluctuations and distance from the outfall have been accounted
for.
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Figure 3.30 shows that there are likely to be inter-annual differences in water quality in this area as
samples are segregated by sampling year. It is clear from Figure 3.30 that the multivariate water
quality profile of each sample is most similar to other samples collected in the same year. The
exception to this is one sampling event from each year, which are segregated. These two sampling
events are both winter months (see Figures 3.30 and 3.31). This dataset is limited to just two years
of sampling however so it is difficult to determine the source of this variability.
As can be seen in Figure 3.31, the winter months are separated from samples taken during other
times of the year. It can be clearly seen here that the coastal water quality is quite different in winter
compared to other times of the year. The multivariate water quality profile of samples is generally
more similar during spring, summer and autumn. This is predominantly due to increased oxidised
nitrogen levels at that time. The distribution of samples, when denoted by sampling events (Figure
3.32), shows that there is quite a strong association between samples taken within two days of each
other. It is clear from this plot that the multivariate water quality profile of each sample is most similar
to other samples collected in the same event and that sampling events can be easily differentiated.
It is sample date however which most strongly groups the samples and which is the variable that
explains most variation in the dataset. Figure 3.33 shows that the multivariate water quality profile of
each sample is most similar to other samples collected on the same day.
Sample distance from the diffuser has been indicated on the plot in Figure 3.34 and shows that there
is a clear delineation of samples by distance from the diffuser within each day of sampling. This
illustrates the significance of the outfall as a driver of local water quality. Notably, samples taken on
the outfall (i.e. distance of 0 m) appear to segregate from samples taken at the next nearest two
distances which are 30 m and 100 m. Within a number of sampling days, samples taken at 250 m
and 500 m are grouped with samples taken at the reference sites (2 km). This model suggests
therefore that at those times, there is a relationship with distance from the outfall in the immediate
vicinity of the outfall (i.e. out to 100 m and to a lesser extent to 250 m). At other times it appears likely
that there is a more pronounced gradient effect occurring as water quality changes with distance from
the outfall.
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1050-5-10-15
10
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dbRDA1 (38% of fitted, 25.6% of total variation)
db
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Sampling
Figure 3.30 Distance based redundancy analysis plot of the fitted multivariate regression
model. Samples collected in the same sampling year are categorised by coloured symbols.
1050-5-10-15
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dbRDA1 (38% of fitted, 25.6% of total variation)
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Spring
Summer
Autumn
Winter
Season
Figure 3.31 Distance based redundancy analysis plot of the fitted multivariate regression
model. Samples collected in the same season are categorised by coloured symbols.
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1050-5-10-15
10
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dbRDA1 (38% of fitted, 25.6% of total variation)
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July 2011
October 2011
February 2012
April 2012
June 2012
October 2012
February 2013
April 2013
Sampling Period
Figure 3.32 Distance based redundancy analysis plot of the fitted multivariate regression
model. Samples collected in the same sampling event are categorised by coloured symbols.
1050-5-10-15
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dbRDA1 (38% of fitted, 25.6% of total variation)
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15/10/2012
16/10/2012
5/02/2013
6/02/2013
2/04/2013
18/07/2011
19/07/2011
12/10/2011
13/10/2011
13/02/2012
14/02/2012
23/04/2012
27/06/2012
28/06/2012
Sample date
Figure 3.33 Distance based redundancy analysis plot of the fitted multivariate regression
model. Samples collected on each day are categorised by coloured symbols.
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1050-5-10-15
10
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dbRDA1 (38% of fitted, 25.6% of total variation)
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0
30
100
250
500
2000
Distance
Figure 3.34 Distance based redundancy analysis (dbRDA) plot of the fitted multivariate
regression model. Samples collected at each sampling distance from the outfall (in meters) are
categorised by coloured symbols.
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4 DISCUSSION
4.1 Water Quality Study
The objective of this study was to characterise the impacts of Burwood Beach WWTW discharge of
effluent and biosolids on water quality in the receiving environment. To assess the gradient and
extent of impact of discharges on the receiving environment, physicochemical parameters and
concentrations of nutrients, chlorophyll a and faecal indicators were measured at increasing distances
from the Burwood Beach WWTW outfall diffusers. Parameters were compared to the relevant
guidelines to identify compliance. This included the Australian and New Zealand Environment and
Conservation Council (ANZECC) Guidelines for Fresh and Marine Water Quality (2000), the New
South Wales Environmental Protection Authority (NSW EPA) Marine Water Quality Guidelines (2000)
and the National Health and Medical Research Council (NHMRC) Guidelines for Managing Risks in
Recreational Waters (2008).
For the purpose of this study, impacts were defined as differences or patterns of decreasing
concentrations or guideline exceeded values of parameters with distance from the outfall.
4.1.1 Physicochemistry and Qualitative Parameters
Physicochemical parameters, including dissolved oxygen, turbidity and pH did not vary across sites or
exhibit any relationship with distance from the outfall. Temperature exhibited a clear seasonal
pattern with the exception of measurements at the mid-water depth during February 2012, which were
variable and colder in comparison to the other February sampling event in 2013. This pattern is
suggested to be due to a reported cyclonic eddy during this event (see Section 4.1.2 for further
discussion), but highlights that the physicochemical data can sometimes provide insight into
environmental patterns that may help to explain the data. Dissolved oxygen and pH did not exhibit
strong spatial patterns but did vary considerably between sampling events. Parameters such as
dissolved oxygen also varied between two sampling days within single sampling events.
Turbidity provides an indication of the presence of suspended particulate and colloidal matter in the
water column and can be elevated in the receiving environment of WWTWs due to the release of
sewage effluent and biosolids. In addition, in offshore coastal regions, turbidity can be elevated due
to factors such as wind, waves and current or due to processes such as upwelling (Everett et al.
2012). During the first three sampling events of this study, turbidity was removed from the data set.
The remaining five sampling events showed a very similar pattern for turbidity and few values were
found to exceed the ANZECC (2000) guideline.
The ANZECC (2000) guidelines outline using a measure of light attenuation, such as a Secchi disc
depth, in coastal and marine waters instead of turbidity. However, the use of the Secchi disc to
measure water clarity in coastal and marine waters, over repeated sampling events, is also
questionable and would not be recommended for future water quality programs around Burwood
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Beach WWTW. The Secchi disc is a subjective parameter which is impacted by user bias. Its use
should also really be standardised for the time of day, weather conditions, especially sunlight and the
swell conditions. For these reasons it is not considered a practical and useful measure in coastal
marine water quality programs. An alternative measure, which could be used in combination with
instrument measurements of turbidity, would be measurement of the total suspended solids (TSS) in
the water samples collected in-situ. Total suspended solids (TSS) in water samples has been shown
to have a direct linear relationship with turbidity (Packman et al. 1999). It is an analytical
measurement that compliments turbidity as it provides a weight measurement of the particulate
material in water samples and does not rely on a calibrated instrument. Another alternative for
measuring light attenuation is measurement of the Photosynthetically Active Radiation (PAR), which
represents the fraction of sunlight with a spectral range from 400 to 700 nm, expressed in µmol
(photons) m-2
s-1
or microEinsteins. Increases in PAR enhance the light reactions of photosynthesis
before reaching a saturation point. In any region, the amount of photosynthetically active radiation
changes seasonally and varies depending on time of day.
Other parameters suggested by the ANZECC (2000) guidelines that were measured in this study
were the presence of an odour and surface scum or oils at each sample site. Odour may not be
reliable as it is dependent on the wind direction and subjectivity of the observer. The same applies for
the measure of ‘surface scum or oils’. The presence of sea foam is common on the ocean and could
be unrelated to an outfall. The variable of the presence or absence of a visible plume was included
and a basic analysis indicated that the presence of a plume is strongly and positively correlated with
distance from the outfall. This variable stills has the inevitable potential for observer bias and
subjective interpretation.
The physicochemical results are important as they provide baseline data for this region and will help
in the design and interpretation of future water monitoring programs.
4.1.2 Nutrients, Chlorophyll a and Faecal Indicators
Spatial trends indicated that some of the tested parameters had relationships with distance from the
outfall. Within some sampling events, levels of ammonia, total nitrogen, enterococci and faecal
coliforms and chlorophyll a, and to a more limited extent, total phosphorus, were all found to decrease
with distance from the outfall, suggesting that the outfalls are a significant source of these
constituents in the receiving environment surveyed. This pattern was evident during July 2011 and
the latter four sampling for the parameters of ammonia, total nitrogen, enterococci and faecal
coliforms. For chlorophyll a, this pattern was evident in October 2012 and February 2013.
Separate analysis of the nutrient, chlorophyll a and faecal indicator data was undertaken by CEE
(2013) with the dataset pooled over sampling events and divided into zones (Appendix 3). This
analysis outlines the extent of the footprint for selected parameters. The following parameters were
noted to have a footprint that impacts on water quality: ammonia, organic nitrogen, total nitrogen, total
phosphorus, enterococci and faecal coliforms. The results for ammonia, enterococci and faecal
coliforms show that there are clear and consistent footprints which extend to over 500 m from the
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outfall. The footprint for organic nitrogen extends to over 100 m from the outfall. The footprints for
total nitrogen, total phosphorus extend to over 250 m from the outfall.
It is well established that the NSW coastline receives nutrient rich eddies from the East Australian
Current (EAC) (Suthers et al. 2011). Local changes in coastal bathymetry are thought to predispose
certain areas, including Port Stephens, Newcastle, Port Hacking to Wollongong and Jervis Bay, to
EAC induced slope water intrusions (Lee et al. 2001). The main flow of the EAC is known to separate
from the NSW coast at Port Stephens, which is approximately 25 km NE of Newcastle. The coastal
circulation north of Port Stephens is dominated by a southward flowing EAC that is highly energetic,
flowing with currents of 2 m s-1
. Topographic variations near Laurieton (north of Port Stephens) are
thought to create high bottom stress that drives the EAC down the coast to Port Stephens where it
then upwells and separates from the coast. Instability along the front of the warm EAC current and
the colder Tasman sea has been shown to often lead to the formation of large (~150 km) warm core
anticyclonic eddies and smaller (20 – 50 km) cyclonic eddies that may persist for days to many weeks
at a time (Cresswell and Legeckis 1986; Pritchard et al. 2001). Separations of the EAC along the
north coast of NSW have been shown to correspond with high levels of chlorophyll a mass along the
shelf (Tranter et al. 1986). These periods of upwelling have been found to be seasonal (peaking
during summer/spring) (Pritchard et al. 1998). Where parameters exceeded the guidelines with a
similar magnitude across all sites, this could be due to upwelling events; although this is speculation
without knowing the timing of most upwelling events during the study period. Elevated values could
also potentially be due to alternative sources of nutrients, such as terrestrial runoff, or other natural
processes such as upwelling events.
The highly variable mid-water results recorded in the February 2012 sampling event are likely to have
been caused by a cold water upwelling event or shelf intrusion. During January - March 2012, the
website for the Integrated Marine Observing System (IMOS) reported that there was a cyclonic eddy
upwelling of deeper and cooler waters from the continental shelf in coastal waters from Sydney to
Bryon Bay (IMOS 2012). The nitrite + nitrate values that exceeded guidelines observed in the
February 2012 sampling event all occurred at mid-water. There were also lower temperatures
recorded at the mid-water depth which mimic the nitrite + nitrate results. Interestingly, high levels of
oxidised nitrogen were also observed in February 2012 around the Boulder Bay WWTW in the
concurrent water quality study for that outfall. Based on this information, it is suggested that this cold
water eddy may have caused nitrites + nitrates to be highly variable and exceed guidelines. Water
quality profiling through the water column to depth (i.e. collection of physicochemical readings every
0.5 m) is one way to assess the stratification of the water column and understand impacts from
upwelled water in this region.
Chlorophyll a concentrations were elevated within 500 m of the outfall during October 2012 and
February 2013. In October 2012 and February 2013, there was 45% and 31 %, respectively, of total
samples that exceeded the ANZECC (2000) guideline of 1 mg/L and all were within 500 m of the
outfall. During October 2012 and February 2013, there was also observed elevated values of some
nutrients (i.e. ammonia, organic nitrogen, total nitrogen and total phosphorus) in comparison to most
sampling events. While the outfall could be responsible for this pattern during October 2012 and
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February 2013, during some sampling events there was also occasional increase of chlorophyll a,
over 500 m from the outfall. Increases in chlorophyll a were noted in some samples (i.e. 1.5- 5 % of
total samples) during July 2011, October 2011, February 2012, April 2012 and April 2013 at sites
located at 500 m or 2 km. These sporadic and occasional occurrences of chlorophyll a at sites > 500
m do suggest that there is also an alternative source of chlorophyll a in the study area, which should
be considered in interpreting the findings.
The faecal indicators enterococci and faecal coliforms also showed strong evidence of outfall related
elevation in most sampling events. High CFU counts were often present at distances of 0 m to 500 m
but were then very low at the reference sites (2 km). Although the Burwood Beach outfall is located
1500 m offshore, the exceedance graphs suggest that the waters within 500 m of the outfall would not
be suitable for primary contact recreation (such as swimming and diving) on almost any of the days
sampled in this study. There is Beachwatch data for enterococci for the same period as this study
which includes only 4 values that exceeded guidelines in 169 samples (NSW OEH 2013). The main
limitation of comparing sites within 500 m of the outfall with sites at 2 km is evident here. We have no
information (apart from Beachwatch data) about what is occurring between 500 m and 2 km. The
findings of this study suggest that the footprint of impact from Burwood Beach on enterococci levels is
between 500 m and > 2 km. It is recommended that future programs include sampling sites at 750 m,
1000 m and 1500 m from the outfall along the north-east/south-west axis to enable better resolution
of the zone of impact for enterococci and also for other parameters.
4.1.3 Analysis of Water Quality Data (nutrients, chlorophyll a and
faecal indicators)
The Burwood Beach WWTW is likely responsible for the observed patterns for ammonia, total
nitrogen, enterococci, faecal coliforms and to a more limited extent, total phosphorus. For ammonia,
there was an increased magnitude and frequency of samples that didn’t meet water quality guideline
values with proximity to the outfall in seven of the eight sampling events. For enterococci and faecal
coliforms, this pattern was strong for four sampling events (July 2011, June 2012, October 2012 and
April 2013) and to a lesser extent for the other four sampling events. For faecal coliforms, this pattern
was evident in February 2013 and April 2013. Total phosphorus was elevated at the outfall sites in
five of the eight sampling events. A multivariate regression analysis was used to confirm this
hypothesis and determine the size of that effect. This analysis showed that date of sampling was the
most significant factor in explaining fluctuations in the multivariate dataset (p = 0.001, R2 = 60%)
showing that water quality fluctuates over very short periods, i.e. daily. This is not surprising given
that in each sampling event, sampling was undertaken over two days. Daily variability seen in the
water quality could be due to natural variation (e.g. currents, tides, upwelling etc.), anthropogenic
sources (i.e. the outfall or otherwise) or both. There will also be an interaction between environmental
and anthropogenic sources as different conditions (i.e. water temperature, salinity and pH) will
influence the behaviour and concentrations of anthropogenic sources of nutrients, chlorophyll a and
faecal indicators upon entering the receiving environment of the outfall (Hughes 2003). High temporal
variability in marine water quality programs are common but can pose a challenge in determining if
there are significant impacts due to a point source such as WWTW. The influence of daily variation
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was thus eliminated by holding the factor of daily variation constant in a sequential analysis. The
factor of distance from the outfall was then found to be significant factor (p = 0.001, R2 = 6.5%). This
result shows, that despite the day to day variability, distance from the outfall is a significant predictor
of water quality. This analysis supports the graphs and summary of the results which suggest that
during this study Burwood Beach WWTW was a significant source of ammonia, total nitrogen,
enterococci, faecal coliforms and to a more limited extent, total phosphorus. While the amount of
variation caused by distance from the outfall (6.5%) may seem small in comparison to daily variation
(60%), the small contribution to overall variability is enough to show clear patterns where water quality
guidelines are triggered for nutrients, chlorophyll a and faecal indicators with distance from the outfall.
Aside from sampling date and distance from the outfall, the multivariate analysis considered other
factors that may have influenced the water quality. Diffuser flow rates, depth at site, direction from
outfall, rainfall in the preceding days, numerous functions of site co-ordinates, season and sampling
year were not significant factors that attributed to the variation in the multivariate water quality profile.
The inclusion of natural sources of variation (i.e. such as upwelling, current and other environment
sources) could improve the models capacity to represent real world fluctuations in water quality
around the outfall. The strength and direction of the current are likely to be important as stronger
currents create higher dilution which should result in lower concentrations of the discharge. The
current transports the plume and so it would be expected that only the sites down-current of the
diffuser will have any contribution from the discharge. This has the potential to create large variability
in the measurements even if the relative effect of the plume is large.
Another factor that could have attributed to the variability observed in this study could be that the
sampling was undertaken over different tides (ebb and flood) and moon phases (spring and neap),
which can also introduce variability into datasets as these factors are known to influence water
chemistry (Sutherland 1981; Pennock et al. 1994; Olila and Reddy 1995; ANZECC 2000). It is
outlined in ANZECC (2000) that the full tidal and diurnal ranges of physicochemical parameters,
including over sunny and dull days, of that region should be firstly be understood in order to
adequately interpret data in relation to anthropogenic impacts. This source of variation could be
partially addressed by holding one factor consistent, i.e. sampling over both ebb and flood tides,
holding the moon phase consistent, or by sampling over spring and neap moons, holding the tide
consistent. Logistically, albeit difficult (due to having to mobilise quickly when weather conditions
permit and undertake all the sampling within one day), it can be done in future programs to help
address this issue. It would be advisable that future studies consider sampling over both ebb/flood
tides to address the potential influence of these factors to help eliminate some variation.
Mention should also be made here of the methodology used in determining the occurrence of water
quality guidelines that are triggered. The ANZECC (2000) guidelines recommend that median values
from a minimum sample N of five are used to compare with low risk trigger values. For chemical
analyses, this is very costly and not standard practice therefore comparison of individual values was
done. It should be considered that the ANZECC (2000) procedure of using median values from a
sample number of 5 could have revealed a lower number of values above trigger levels for the
nutrient, chlorophyll a and faecal indicator results as it would have likely reduced the risk of potential
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outlier measurements exceeding the trigger index. By comparing individual results to the guidelines a
higher resolution can be attained for patterns of guideline values that are triggered both spatially and
temporally. This more conservative approach is complemented by the multivariate analysis that
calculates the contribution of the outfall to water quality variability over time and space. What neither
of these measures does is quantify the effect of the outfall on the marine ecology of the region.
As well as providing assessment of the impacts of the Burwood Beach WWTW on water quality in the
receiving environment, this study has developed baseline data for the region which will help with the
design and implementation of future water monitoring programs.
4.2 Patterns between Water Quality Results and Effluent and Biosolids Composition
As provided in the introduction, the composition (including a suite of physicochemical and nutrient
parameters) of final treated effluent and biosolids has been routinely monitored by Hunter Water and
this data is available from 2006 - 2013. Concentrations of ammonium nitrogen, nitrites + nitrates, total
kjeldhal nitrogen and total nitrogen were examined in effluent and biosolids during the period of the
current water quality study (Figure 4.1), to attempt to predict any relationships with the composition of
effluent and biosolids and values that exceeded guidelines observed in the receiving environment.
Unfortunately, no data is available for enterococci or faecal coliforms, which were also found to be an
issue in this study. One of the concerns with comparing the water quality data to the effluent and
biosolids data is that the sampling dates do not coincide. The closest available effluent and biosolids
sampling dates are highlighted on Figure 4.1 and these were within one week prior to those dates of
the water sampling study. However, there is considerable short term variability in the results of the
effluent and biosolids data between the fortnightly / monthly sampling. It would be valuable if future
water quality monitoring programs could match the sampling dates to those of the effluent and
biosolids testing, although this may not be possible due to difficulties in finding suitable water
sampling conditions and having to undertake license sampling on specified days.
In the current water quality study, ammonia was elevated during the last four sampling events,
including June 2012, October 2012, February 2013 and April 2013. In the effluent, ammonia was
found to be elevated in effluent sampled in October 2012 and February 2013. In the biosolids,
ammonia was also elevated in biosolids in October 2012.
The concentrations of nitrates + nitrites in effluent does not provide any insight into the results of the
water quality study as the patterns in effluent do not match that found in the water quality study (i.e.
levels were elevated during July 2011, February 2011 and June 2012). However, the concentrations
of total nitrogen in effluent may relate to values that exceeded guidelines that were observed during
the water quality study. Levels of total nitrogen were elevated in effluent sampled in October 2012
and February 2013, in comparison to other sampling events. In the water quality study, total nitrogen
was elevated during the last four sampling events which included October 2012 and February 2013.
Total phosphorus in effluent does not provide any insight into the relationships observed in the water
quality study, as levels in effluents were similar in those months that coincided with water sampling.
There was an overall trend in the water quality data for elevated levels of many parameters (i.e.
ammonia, total nitrogen, chlorophyll a, enterococci, faecal coliforms and chlorophyll a) during July
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2011 and the last four sampling events from June 2012 onwards. The effluent and biosolids
chemistry results in Table 1.2 could partially help to explain this trend for ammonia and total nitrogen,
but again this is a large assumption without knowing what the effluent and biosolids concentrations
were on the water sampling dates.
Figure 4.1 Fortnightly testing of effluent characteristics during the Burwood Beach Water
Quality Study. Red days indicate the effluent or biosolids sampling dates that coincide (within
the week prior to) the closest to the water quality sampling. In effluent, a = ammonium nitrate,
b = total nitrogen, c = nitrates + nitrites, d = total nitrogen, e = total phosphorus and in
biosolids, f = ammonium nitrate.
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5 CONCLUSIONS
During half the sampling events (July 2011, June 2012, October 2012 and April 2013), there
was a clear footprint of elevated ammonia which extended to over 500 m from the outfall.
Organic nitrogen was elevated during some sampling events at the outfall and at 100 m
which could suggest an occasional footprint extending to 100 m from the outfall.
For total nitrogen, there was a consistent footprint to more than 250 m from the outfall,
particularly during the latter four sampling events.
Chlorophyll a was elevated around the outfall and mixing zones during October 2012 and
February 2013. There were also sporadic occurrences at > 500 m during other sampling
events.
Enterococci and faecal coliforms showed a footprint which extended to more than 500 m from
the outfall during most sampling events.
The high proportion of total nitrogen values (across all zones) that exceed the water quality
guideline of 0.12 mg/L suggests the need for further investigation to develop a site specific
trigger value for total nitrogen.
Other physiochemical parameters, including dissolved oxygen and pH were homogenous
across site within sampling events but varied over sampling events and should continue to be
monitored in all future WQ programs.
Water quality within 500 m of the Burwood Beach WWTW outfall rarely met the guidelines for
primary contact recreation (ANZECC 2000; NSW EPA 2000). Two parameters were
responsible for these results including enterococci and faecal coliforms.
A multivariate analysis (of nutrients, chlorophyll a and faecal indicators) found that local water
quality was highly variable on temporal scales from days to seasons, which is not surprising
for marine water quality programs. When the factor of daily variability was held constant, it
was seen that distance from the outfall is a significant predictor of water quality. This
suggests that the outfall has an effect on local water quality across the range of parameters
measured.
The highly variable mid-water results recorded in the February 2012 sampling event are likely
to have been caused by a cold water upwelling event or shelf intrusion.
The composition of Burwood Beach WWTW effluent and biosolids, sampled at times before
the water quality study (though on different days), partially helps to explain some of the water
quality results including the trends observed for ammonia and total nitrogen.
Based upon the findings of this study, any future increases in effluent and biosolids
discharges from the Burwood Beach WWTW is likely to result in continued impacts to water
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quality, especially for nutrients, chlorophyll a and faecal indicators. This would be dependent
on a number of factors including the rate of discharge, concentrations in the effluent and the
dilution in the receiving environment.
In summary, the water quality data indicates a footprint of the outfall discharge extending to
about 500 m from the outfall.
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6 ACKNOWLEDGEMENTS
We would like to thank those that assisted with the design and implementation of this study. Hunter
Water, Consulting Environmental Engineers (CEE), NSW EPA, NSW Marine Parks and NSW DPI
Fisheries assisted with the design of the sampling program and methodology. CEE also provided a
separate analysis of the data. Sandy Bottom Boat Charters, a commercial fishing charter, provided a
boat for sampling. WorleyParsons undertook all the water sampling, data analysis and report
preparation. Australian Laboratory Services (ALS) undertook all the water chemistry analysis.
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Appendix 1 – Chain of Custody Forms for Water Quality
Analysis
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Appendix 2 – Raw Water Quality data
July 2011
Sample date:Sampling period
Sample ID DirectionDistance
from diffuser (m)
DepthChlorophyll a (mg/m3)
Enterococci (CFU/100ml)
Faecal Coliforms
(CFU/100ml)
Organic Nitrogen as N (mg/L)
Ammonia as N (mg/L)
Nitrite + Nitrate as N (mg/L)
Inorganic Nitrogen as N (mg/L)
Total Nitrogen as N (mg/L)
Total Phosphorus as P (mg/L)
Depth at site (m)
Depth at mid water (m)
Sechi Disc Depth (m)
Turbidity (NTU)
Temperature (oC)
Conductivity (mS/cm)
pHDissolved oxygen (mg/L)
Salinity (‰)
18/07/2011 July 2011 WQ1S DIF 0 Surface <1 <1 <1 0.2 <0.005 0.085 0.03 0.13 0.017 24 12.0 2.25 3.6 17.39 5.5218/07/2011 July 2011 WQ1M DIF 0 Midwater <1 <1 <1 0.2 0.006 0.077 0.04 0.09 0.017 24 12.0 4.1 17.16 5.5118/07/2011 July 2011 WQ2S DIF 0 Surface 1 <1 1 0.2 <0.005 0.086 0.04 0.1 0.015 24.4 12.2 4.5 3.8 17.44 5.5218/07/2011 July 2011 WQ2M DIF 0 Midwater <1 <1 <1 0.2 <0.005 0.086 0.03 0.09 0.017 24.4 12.2 4.1 17.32 5.5218/07/2011 July 2011 WQ3S DIF 0 Surface <1 <1 <1 0.2 <0.005 0.088 0.04 0.09 0.018 26.2 13.1 2 11 17.51 5.5218/07/2011 July 2011 WQ3M DIF 0 Midwater <1 1 <1 0.1 <0.005 0.09 0.05 0.09 0.016 26.2 13.1 6.8 17.47 5.5218/07/2011 July 2011 WQ4S DIF 0 Surface <1 70 200 0.2 0.048 0.084 0.03 0.16 0.022 21.9 11.0 2.5 3.9 17.37 5.5118/07/2011 July 2011 WQ4M DIF 0 Midwater <1 60 250 0.2 0.046 0.083 0.04 0.14 0.022 21.9 11.0 3.8 17.41 5.5118/07/2011 July 2011 WQ5S DIF 30 Surface <1 <1 <1 0.2 <0.005 0.083 0.04 0.1 0.015 21.3 10.7 2.5 4.4 17.36 5.5118/07/2011 July 2011 WQ5M DIF 30 Midwater <1 <1 <1 0.1 <0.005 0.084 0.04 0.1 0.013 21.3 10.7 4.4 17.3 5.5118/07/2011 July 2011 WQ6S DIF 30 Surface <1 50 280 0.2 0.081 0.076 0.03 0.18 0.02 22.3 11.2 1.75 5.9 17.33 5.5018/07/2011 July 2011 WQ6M DIF 30 Midwater <1 4 48 0.1 0.011 0.084 0.03 0.11 0.015 22.3 11.2 4.4 17.39 5.5218/07/2011 July 2011 WQ7S DIF 30 Surface 2 70 250 0.1 0.068 0.081 0.04 0.18 0.018 23.6 11.8 2 4.6 17.33 5.5018/07/2011 July 2011 WQ7M DIF 30 Midwater <1 2 1 <0.1 <0.005 0.086 0.04 0.1 0.014 23.6 11.8 4.6 17.44 5.5218/07/2011 July 2011 WQ8S DIF 30 Surface 1 180 250 0.1 0.056 0.08 0.04 0.17 0.026 21.1 10.6 2.25 5 17.33 5.5018/07/2011 July 2011 WQ8M DIF 30 Midwater <1 210 280 <0.1 0.014 0.077 0.04 0.1 0.021 21.1 10.6 5.9 17.14 5.5118/07/2011 July 2011 WQ9S N 100 Surface <1 <1 <1 0.1 <0.005 0.083 0.04 0.08 0.014 22.6 11.3 2.25 5.6 17.5 5.5218/07/2011 July 2011 WQ9M N 100 Midwater 1 1 <1 <0.1 <0.005 0.084 0.04 0.09 0.014 22.6 11.3 5.4 17.4 5.5118/07/2011 July 2011 WQ10S NE 100 Surface <1 40 130 0.2 0.052 0.082 <0.01 0.14 0.01 23.5 11.8 2 4.6 17.38 5.5018/07/2011 July 2011 WQ10M NE 100 Midwater <1 <1 1 <0.1 <0.005 0.087 0.05 0.1 0.012 23.5 11.8 4.4 17.52 5.5218/07/2011 July 2011 WQ11S E 100 Surface <1 12 73 0.1 0.038 0.083 0.04 0.13 0.016 23.4 11.7 2.25 4.8 17.36 5.5018/07/2011 July 2011 WQ11M E 100 Midwater <1 1 1 <0.1 <0.005 0.088 0.05 0.09 0.014 23.4 11.7 4.1 17.51 5.5218/07/2011 July 2011 WQ12S SE 100 Surface <1 <1 <1 <0.1 <0.005 0.085 0.05 0.09 0.016 23.3 11.7 4.5 17.61 5.5218/07/2011 July 2011 WQ12M SE 100 Midwater <1 <1 <1 0.4 <0.005 0.088 0.05 0.1 0.015 23.3 11.7 4.3 17.59 5.5218/07/2011 July 2011 WQ13S S 100 Surface <1 170 280 0.4 0.025 0.083 0.04 0.13 0.023 23 11.5 5.3 17.42 5.5118/07/2011 July 2011 WQ13M S 100 Midwater <1 20 24 0.1 <0.005 0.094 0.05 0.1 0.017 23 11.5 4.2 17.47 5.5219/07/2011 July 2011 WQ14S SW 100 Surface <1 260 360 <0.1 0.044 0.076 0.04 0.16 0.023 20.1 10.1 1.75 4.9 17.17 5.5319/07/2011 July 2011 WQ14M SW 100 Midwater <1 210 90 <0.1 0.012 0.077 0.04 0.1 0.014 20.1 10.1 4 17.22 5.5119/07/2011 July 2011 WQ16S NW 100 Surface <1 140 400 0.1 0.063 0.074 0.03 0.17 0.02 22.3 11.2 2 6.5 17.14 5.5019/07/2011 July 2011 WQ16M NW 100 Midwater <1 160 300 <0.1 0.047 0.075 0.04 0.14 0.032 22.3 11.2 6.2 17.16 5.5119/07/2011 July 2011 WQ1BS SE 100 Surface <1 170 400 0.2 0.055 0.075 0.04 0.16 0.022 22.3 11.2 1 9.1 17.16 5.4919/07/2011 July 2011 WQ1BM SE 100 Midwater <1 120 300 <0.1 0.033 0.076 0.04 0.13 0.02 22.3 11.2 8 17.15 5.5119/07/2011 July 2011 WQ17S N 250 Surface <1 24 140 <0.1 0.021 0.077 0.04 0.11 0.015 22 11.0 2 5.6 17.18 5.5119/07/2011 July 2011 WQ17M N 250 Midwater <1 16 62 <0.1 0.006 0.075 0.05 0.09 0.015 22 11.0 3.8 17.15 5.5119/07/2011 July 2011 WQ18S NE 250 Surface <1 96 290 <0.1 0.027 0.076 0.04 0.1 0.018 25.1 12.6 2.25 3.7 17.18 5.5119/07/2011 July 2011 WQ18M NE 250 Midwater <1 64 220 <0.1 0.01 0.076 0.04 0.1 0.012 25.1 12.6 3.6 17.16 5.5119/07/2011 July 2011 WQ20S SE 250 Surface <1 <2 <2 <0.1 <0.005 0.082 0.04 0.09 0.016 24 12.0 2 20.8 17.27 5.5119/07/2011 July 2011 WQ20M SE 250 Midwater <1 <2 <2 <0.1 <0.005 0.084 0.04 0.1 0.014 24 12.0 13.8 17.22 5.5119/07/2011 July 2011 WQ22S SW 250 Surface <1 200 240 <0.1 0.034 0.076 <0.01 0.13 0.02 23 11.5 2 6.4 17.22 5.5119/07/2011 July 2011 WQ22M SW 250 Midwater <1 100 68 <0.1 0.009 0.079 0.05 0.09 0.018 23 11.5 6.3 17.25 5.5119/07/2011 July 2011 WQ24S NW 250 Surface <1 76 280 <0.1 0.053 0.075 0.04 0.15 0.021 23.4 11.7 2 4.9 17.18 5.5019/07/2011 July 2011 WQ24M NW 250 Midwater <1 6 34 <0.1 0.006 0.074 0.04 0.1 0.019 23.4 11.7 5.3 17.15 5.5119/07/2011 July 2011 WQ2BS SE 250 Surface <1 140 210 <0.1 0.054 0.074 0.04 0.15 0.02 22.5 11.3 1.5 4.7 17.18 5.5019/07/2011 July 2011 WQ2BM SE 250 Midwater <1 180 440 <0.1 0.056 0.076 0.03 0.15 0.02 22.5 11.3 3.7 17.2 5.5119/07/2011 July 2011 WQ25S NE 500 Surface <1 18 20 <0.1 0.008 0.076 0.05 0.09 0.014 25.3 12.7 2 3.2 17.22 5.5119/07/2011 July 2011 WQ25M NE 500 Midwater <1 20 38 0.1 0.006 0.075 0.05 0.1 0.018 25.3 12.7 2.9 17.13 5.5119/07/2011 July 2011 WQ26S SE 500 Surface <1 <2 <2 <0.1 <0.005 0.087 0.05 0.09 0.018 26.1 13.1 2.75 2.9 17.22 5.5219/07/2011 July 2011 WQ26M SE 500 Midwater <1 <2 <2 <0.1 <0.005 0.087 0.05 0.12 0.017 26.1 13.1 2.4 17.32 5.5119/07/2011 July 2011 WQ27S SW 500 Surface <1 <2 <2 0.1 <0.005 0.08 0.04 0.09 0.016 24 12.0 2.25 2.8 17.29 5.5219/07/2011 July 2011 WQ27M SW 500 Midwater <1 <2 <2 0.2 <0.005 0.08 0.04 0.1 0.018 24 12.0 2.9 17.27 5.5119/07/2011 July 2011 WQ28S NW 500 Surface <1 100 230 <0.1 0.045 0.074 0.05 0.14 0.02 19 9.5 2 3.3 17.21 5.5019/07/2011 July 2011 WQ28M NW 500 Midwater <1 8 50 <0.1 <0.005 0.076 0.05 0.1 0.014 19 9.5 3.7 17.21 5.5019/07/2011 July 2011 WQ3BS SE 500 Surface <1 370 400 <0.1 0.068 0.078 0.04 0.19 0.022 19.9 10.0 1.75 5 17.21 5.5019/07/2011 July 2011 WQ3BM SE 500 Midwater <1 300 200 <0.1 0.029 0.078 0.03 0.18 0.038 19.9 10.0 4.1 17.22 5.5119/07/2011 July 2011 WQ29S REFNE 2000 Surface <1 <2 <2 <0.1 <0.005 0.075 0.04 0.09 0.01 19.2 9.6 2.75 4.1 17.22 5.5119/07/2011 July 2011 WQ29M REFNE 2000 Midwater <1 <2 <2 <0.1 <0.005 0.072 0.04 0.09 0.012 19.2 9.6 3.4 17.12 5.5119/07/2011 July 2011 WQ30S REFNE 2000 Surface <1 <2 <2 <0.1 <0.005 0.081 0.04 0.09 0.016 25.3 12.7 2.25 2.9 17.27 5.5119/07/2011 July 2011 WQ30M REFNE 2000 Midwater <1 <2 <2 <0.1 0.005 0.084 0.05 0.1 0.015 25.3 12.7 3.4 17.3 5.51
NB1: Where data are preceded by a less than sign (<), the concentration was below the limit of reporting for that analysis.
NB2: Data for pH, dissolved oxygen and salinity were collected from February 2012 onwards.
October 2011
Sample date: Sampling period Sample ID DirectionDistance from
diffuser (m)Depth
Chlorophyll a (mg/m3)
Enterococci (CFU/100ml)
Faecal Coliforms
(CFU/100ml)
Organic Nitrogen as N (mg/L)
Ammonia as N (mg/L)
Nitrite + Nitrate as N (mg/L)
Inorganic Nitrogen as N (mg/L)
Total Nitrogen as N (mg/L)
Total Phosphorus as P (mg/L)
Depth at site (m)
Depth at mid water (m)
Sechi Disc Depth (m)
Turbidity (NTU)
Temperature (oC)
Conductivity (mS/cm)
pHDissolved oxygen (mg/L)
Salinity (‰)
12/10/2011 October 2011 WQ1S DIF 0 Surface <1 <1 4 0.07 0.019 <0.002 0.019 0.09 0.012 22.1 11.1 4 7.1 18.48 5.4412/10/2011 October 2011 WQ1M DIF 0 Midwater <1 64 180 0.16 0.071 0.003 0.074 0.23 0.019 22.1 11.1 7.3 17.85 5.4512/10/2011 October 2011 WQ2S DIF 0 Surface <1 <1 <1 0.12 0.006 <0.002 0.006 0.13 0.016 21.5 10.8 3.512/10/2011 October 2011 WQ2M DIF 0 Midwater <1 2 6 0.14 <0.005 <0.002 <0.005 0.14 0.014 21.5 10.812/10/2011 October 2011 WQ3S DIF 0 Surface <1 29 74 0.12 <0.005 <0.002 <0.005 0.12 0.018 22.4 11.2 2.5 7 18.51 5.4412/10/2011 October 2011 WQ3M DIF 0 Midwater <1 2 4 0.07 <0.005 <0.002 <0.005 0.07 0.006 22.4 11.2 7 17.9 5.4412/10/2011 October 2011 WQ4S DIF 0 Surface <1 11 59 0.14 0.009 <0.002 0.009 0.15 0.01 22.8 11.4 312/10/2011 October 2011 WQ4M DIF 0 Midwater <1 19 62 0.09 0.007 <0.002 0.007 0.1 0.015 22.8 11.412/10/2011 October 2011 WQ5S DIF 30 Surface <1 8 35 0.06 <0.005 <0.002 <0.005 0.06 0.01 22.4 11.2 4 6.6 18.47 5.4412/10/2011 October 2011 WQ5M DIF 30 Midwater 2 5 32 0.09 0.01 <0.002 0.01 0.1 0.01 22.4 11.2 7 18.02 5.4413/10/2011 October 2011 WQ6S DIF 30 Surface <1 <2 2 0.09 <0.005 <0.002 <0.005 0.09 0.01 21.9 11.0 3 13.1 18.4 5.4113/10/2011 October 2011 WQ6M DIF 30 Midwater <1 18 40 <0.05 0.072 <0.002 0.072 0.11 0.021 21.9 11.0 12.8 18.85 5.4612/10/2011 October 2011 WQ7S DIF 30 Surface <1 <1 2 0.09 0.008 <0.002 0.008 0.1 0.013 24 12.0 3 6.1 18.54 5.4412/10/2011 October 2011 WQ7M DIF 30 Midwater <1 <1 2 0.07 <0.005 <0.002 <0.005 0.07 0.008 24 12.0 7.6 17.97 5.4413/10/2011 October 2011 WQ8S DIF 30 Surface <1 <2 2 0.08 <0.005 <0.002 <0.005 0.08 0.016 20.9 10.5 3 13.9 18.34 5.4013/10/2011 October 2011 WQ8M DIF 30 Midwater <1 <2 <2 <0.05 <0.005 0.002 <0.005 <0.05 0.005 20.9 10.5 13.6 19.02 5.4812/10/2011 October 2011 WQ9S N 100 Surface <1 1 1 0.12 <0.005 <0.002 <0.005 0.12 0.017 21.3 10.7 3.5 5.6 18.49 5.4412/10/2011 October 2011 WQ9M N 100 Midwater <1 1 2 0.1 <0.005 <0.002 <0.005 0.1 0.01 21.3 10.7 5.5 18.05 5.4413/10/2011 October 2011 WQ10S NE 100 Surface <1 2 2 0.08 0.008 <0.002 0.008 0.09 0.012 24.6 12.3 3.5 13.8 18.58 5.4413/10/2011 October 2011 WQ10M NE 100 Midwater <1 2 6 0.06 0.005 <0.002 0.005 0.06 0.01 24.6 12.3 17 19.01 5.4812/10/2011 October 2011 WQ11S E 100 Surface <1 <1 <1 0.08 <0.005 <0.002 <0.005 0.08 0.016 24.5 12.3 4.5 5.6 18.56 5.4512/10/2011 October 2011 WQ11M E 100 Midwater 1 1 11 0.07 <0.005 <0.002 <0.005 0.07 0.012 24.5 12.3 6.9 17.7 5.4413/10/2011 October 2011 WQ12S SE 100 Surface <1 <2 <2 0.05 0.006 <0.002 0.006 0.06 0.012 24.2 12.1 4 5.6 18.52 5.4313/10/2011 October 2011 WQ12M SE 100 Midwater <1 <2 <2 <0.05 <0.005 <0.002 <0.005 <0.05 0.011 24.2 12.1 5.6 19.01 5.4812/10/2011 October 2011 WQ13S S 100 Surface <1 1 <1 0.12 0.008 <0.002 0.008 0.13 0.014 23.8 11.9 3.5 5.5 18.57 5.4412/10/2011 October 2011 WQ13M S 100 Midwater 2 18 150 0.08 0.022 <0.002 0.022 0.1 0.013 23.8 11.9 6.8 17.8 5.4413/10/2011 October 2011 WQ14S SW 100 Surface <1 <2 <2 0.07 <0.005 <0.002 <0.005 0.07 0.014 22.5 11.3 4 5.9 18.46 5.4113/10/2011 October 2011 WQ14M SW 100 Midwater <1 <2 <2 <0.05 <0.005 <0.002 <0.005 <0.05 0.009 22.5 11.3 7.1 19.06 5.4812/10/2011 October 2011 WQ15S W 100 Surface <1 <1 <1 0.08 0.009 <0.002 0.009 0.09 0.015 21.7 10.9 4.5 4.7 18.58 5.4412/10/2011 October 2011 WQ15M W 100 Midwater <1 2 3 0.08 <0.005 <0.002 <0.005 0.08 0.011 21.7 10.9 5.1 17.91 5.4413/10/2011 October 2011 WQ16S NW 100 Surface <1 <2 <2 0.06 <0.005 <0.002 <0.005 0.06 0.005 20.7 10.4 2.5 4.4 18.4 5.4013/10/2011 October 2011 WQ16M NW 100 Midwater <1 <2 <2 0.05 <0.005 <0.002 <0.005 0.05 0.01 20.7 10.4 4.3 18.5 5.4112/10/2011 October 2011 WQ17S N 250 Surface 2 1 <1 0.13 0.01 0.004 0.014 0.14 0.018 22.5 11.3 3.5 6.3 18.51 5.4412/10/2011 October 2011 WQ17M N 250 Midwater 1 <1 7 0.13 <0.005 <0.002 <0.005 0.13 0.015 22.5 11.3 8 17.99 5.4513/10/2011 October 2011 WQ18S NE 250 Surface <1 <2 <2 0.05 0.007 <0.002 0.007 0.06 0.006 25.2 12.6 4 4.4 18.55 5.4213/10/2011 October 2011 WQ18M NE 250 Midwater <1 28 50 0.05 0.048 <0.002 0.048 0.1 0.013 25.2 12.6 4.7 19.02 5.4912/10/2011 October 2011 WQ19S E 250 Surface <1 <1 <1 0.07 0.008 <0.002 0.008 0.08 0.009 25.4 12.7 3 5.4 18.63 5.4512/10/2011 October 2011 WQ19M E 250 Midwater 1 <1 <1 0.08 <0.005 <0.002 <0.005 0.08 0.013 25.4 12.7 5.5 17.8 5.4313/10/2011 October 2011 WQ20S SE 250 Surface <1 2 <2 <0.05 <0.005 <0.002 <0.005 <0.05 0.009 25.3 12.7 2.5 3.8 18.78 5.4613/10/2011 October 2011 WQ20M SE 250 Midwater <1 <2 <2 <0.05 <0.005 <0.002 <0.005 <0.05 0.006 25.3 12.7 3.7 18.97 5.4812/10/2011 October 2011 WQ21S S 250 Surface <1 3 9 0.1 <0.005 <0.002 <0.005 0.1 0.017 25.1 12.6 3.5 5.4 18.25 5.4012/10/2011 October 2011 WQ21M S 250 Midwater <1 2 5 0.08 <0.005 <0.002 <0.005 0.08 0.013 25.1 12.6 5.8 18 5.4513/10/2011 October 2011 WQ22S SW 250 Surface <1 <2 <2 0.06 <0.005 <0.002 <0.005 0.06 0.01 29.4 14.7 4 3.9 18.8 5.4713/10/2011 October 2011 WQ22M SW 250 Midwater <1 <2 2 0.06 <0.005 <0.002 <0.005 0.06 <0.005 29.4 14.7 4.1 18.81 5.4712/10/2011 October 2011 WQ23S W 250 Surface <1 3 3 0.11 <0.005 <0.002 <0.005 0.11 0.013 19.5 9.8 212/10/2011 October 2011 WQ23M W 250 Midwater <1 1 9 0.1 <0.005 <0.002 <0.005 0.1 0.014 19.5 9.813/10/2011 October 2011 WQ24S NW 250 Surface <1 <2 <2 0.06 <0.005 <0.002 <0.005 0.06 0.013 23 11.5 3.5 4.3 18.44 5.4013/10/2011 October 2011 WQ24M NW 250 Midwater <1 <2 <2 0.06 <0.005 <0.002 <0.005 0.06 0.012 23 11.5 4.6 18.59 5.4512/10/2011 October 2011 WQ25S NE 500 Surface <1 <1 4 0.08 0.006 <0.002 0.006 0.09 0.011 24.3 12.2 312/10/2011 October 2011 WQ25M NE 500 Midwater <1 1 3 0.08 <0.005 <0.002 <0.005 0.08 0.009 24.3 12.213/10/2011 October 2011 WQ26S SE 500 Surface <1 <2 <2 <0.05 <0.005 <0.002 <0.005 <0.05 0.007 26.3 13.2 3.5 4.2 18.91 5.4213/10/2011 October 2011 WQ26M SE 500 Midwater <1 4 2 <0.05 <0.005 <0.002 <0.005 <0.05 <0.005 26.3 13.2 4.1 18.92 5.4812/10/2011 October 2011 WQ27S SW 500 Surface <1 1 10 0.08 0.009 <0.002 0.009 0.09 0.01 23 11.5 3.512/10/2011 October 2011 WQ27M SW 500 Midwater <1 4 29 0.08 <0.005 <0.002 <0.005 0.08 0.01 23 11.513/10/2011 October 2011 WQ28S NW 500 Surface <1 <2 <2 0.05 <0.005 <0.002 <0.005 0.05 0.01 19.8 9.9 3.5 4 18.4 5.4013/10/2011 October 2011 WQ28M NW 500 Midwater <1 <2 <2 0.05 <0.005 <0.002 <0.005 0.05 <0.005 19.8 9.9 4.5 18.33 5.4112/10/2011 October 2011 WQ29S REFNE 2000 Surface <1 <1 <1 0.13 <0.005 <0.002 <0.005 0.13 0.02 18 9.0 212/10/2011 October 2011 WQ29M REFNE 2000 Midwater 2 <1 <1 0.1 <0.005 <0.002 <0.005 0.1 0.01 18 9.012/10/2011 October 2011 WQ30S REFNE 2000 Surface <1 <1 <1 0.12 <0.005 0.003 <0.005 0.12 0.01 24.8 12.4 412/10/2011 October 2011 WQ30M REFNE 2000 Midwater <1 <1 <1 0.06 <0.005 <0.002 <0.005 0.06 0.008 24.8 12.413/10/2011 October 2011 WQ31S REFSW 2000 Surface <1 <2 <2 0.08 <0.005 <0.002 <0.005 0.08 0.013 24.2 12.1 2 4.4 18.41 5.4113/10/2011 October 2011 WQ31M REFSW 2000 Midwater <1 <2 <2 <0.05 <0.005 <0.002 <0.005 <0.05 <0.005 24.2 12.1 4 18.53 5.4513/10/2011 October 2011 WQ32S REFSW 2000 Surface <1 <2 <2 0.06 <0.005 <0.002 <0.005 0.06 0.008 20.9 10.5 2.5 4.1 18.33 5.3913/10/2011 October 2011 WQ32M REFSW 2000 Midwater <1 <2 <2 <0.05 <0.005 <0.002 <0.005 <0.05 0.01 20.9 10.5 4 18.72 5.40
NB1: Where data are preceded by a less than sign (<), the concentration was below the limit of reporting for that analysis.
NB2: Data for pH, dissolved oxygen and salinity were collected from February 2012 onwards.
February 2012
Sample date: Sampling period Sample ID DirectionDistance from
diffuser (m)Depth
Chlorophyll a (mg/m3)
Enterococci (CFU/100ml)
Faecal Coliforms
(CFU/100ml)
Organic Nitrogen as N (mg/L)
Ammonia as N (mg/L)
Nitrite + Nitrate as N (mg/L)
Inorganic Nitrogen as N (mg/L)
Total Nitrogen as N (mg/L)
Total Phosphorus as P (mg/L)
Depth at site (m)
Depth at mid water (m)
Sechi Disc Depth (m)
Turbidity (NTU)
Temperature (oC)
Conductivity (mS/cm)
pHDissolved oxygen (mg/L)
Salinity (‰)
14/02/2012 February 2012 WQ1S DIF 0 Surface <1 8 13 <0.05 <0.005 <0.002 <0.005 <0.01 0.005 21.7 10.8 3.5 x 21.85 5.44 8.13 7.69 36.0614/02/2012 February 2012 WQ1M DIF 0 Midwater <1 32 93 <0.05 0.03 0.1 0.13 0.17 0.028 21.7 10.8 x 15.07 5.51 7.88 5.63 36.613/02/2012 February 2012 WQ2S DIF 0 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 21.8 10.9 4 6.2 22.37 5.47 8.08 7.26 36.3113/02/2012 February 2012 WQ2M DIF 0 Midwater <0.5 <1 <1 <0.05 <0.005 0.005 0.005 <0.01 <0.005 21.8 10.9 5 19.5 5.49 8.01 7.01 36.8313/02/2012 February 2012 WQ3S DIF 0 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 0.006 21.6 10.8 4.5 11.5 22.38 5.47 8.08 7.69 36.3113/02/2012 February 2012 WQ3M DIF 0 Midwater <0.5 <1 <1 <0.05 <0.005 0.003 <0.005 <0.01 <0.005 21.6 10.8 11.4 21.13 5.48 8.05 7.22 36.413/02/2012 February 2012 WQ4S DIF 0 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 0.007 22.3 11.1 4 x 22.51 5.47 8.08 7.65 36.8813/02/2012 February 2012 WQ4M DIF 0 Midwater <0.5 <1 <1 <0.05 <0.005 0.003 <0.005 <0.01 0.006 22.3 11.1 13.7 18.76 5.53 7.95 6.46 36.7714/02/2012 February 2012 WQ5S DIF 30 Surface <1 6 11 <0.05 <0.005 <0.002 <0.005 <0.01 0.006 21.7 10.9 2.5 x 21.81 5.43 8.1 7.58 35.9714/02/2012 February 2012 WQ5M DIF 30 Midwater <1 71 160 <0.05 0.1 0.131 0.231 0.27 0.026 21.7 10.9 x 16.44 5.53 7.91 5.59 36.914/02/2012 February 2012 WQ6S DIF 30 Surface <1 2 1 <0.05 <0.005 <0.002 <0.005 0.02 0.006 21.6 10.8 3.5 x 21.87 5.43 8.19 7.64 36.0114/02/2012 February 2012 WQ6M DIF 30 Midwater <1 67 170 <0.05 0.101 0.154 0.255 0.24 0.045 21.6 10.8 24.8 16.21 5.54 7.91 5.17 36.7214/02/2012 February 2012 WQ7S DIF 30 Surface <1 <1 3 <0.05 <0.005 0.009 0.009 0.02 0.011 23.4 11.7 3 x 21.65 5.40 8.1 7.15 35.7514/02/2012 February 2012 WQ7M DIF 30 Midwater <1 43 140 <0.05 0.035 0.103 0.138 0.17 0.023 23.4 11.7 25.2 16.89 5.52 7.98 5.84 36.6514/02/2012 February 2012 WQ8S DIF 30 Surface <1 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 21.1 10.5 4 x 21.85 5.42 8.1 7.3 3614/02/2012 February 2012 WQ8M DIF 30 Midwater <1 66 190 <0.05 0.155 0.149 0.304 0.34 0.038 21.1 10.5 x 15.5 5.53 7.9 5.06 36.5514/02/2012 February 2012 WQ9S N 100 Surface <1 1 3 <0.05 <0.005 <0.002 <0.005 <0.01 0.009 22.7 11.3 3.5 x 21.84 5.44 8.19 7.58 36.0314/02/2012 February 2012 WQ9M N 100 Midwater <1 1 10 <0.05 0.01 0.116 0.126 0.11 0.02 22.7 11.3 10.3 15.5 5.54 7.85 5.19 36.7914/02/2012 February 2012 WQ10S NE 100 Surface <1 <1 2 0.2 <0.005 0.003 <0.005 0.2 0.036 23.8 11.9 3.5 6 21.45 5.35 8.12 7.62 35.4314/02/2012 February 2012 WQ10M NE 100 Midwater <1 250 300 <0.05 0.015 0.018 0.033 0.03 0.01 23.8 11.9 2.7 15.62 5.53 7.87 5.9 36.5913/02/2012 February 2012 WQ11S E 100 Surface 1 <1 <1 <0.05 <0.005 <0.002 <0.005 0.02 0.009 24.0 12.0 3.5 1.5 21.5 5.35 8.1 7.5 35.4114/02/2012 February 2012 WQ11M E 100 Midwater <1 10 35 <0.05 0.025 0.085 0.11 0.13 0.017 24.0 12.0 4 15.34 5.53 7.91 5.5 36.613/02/2012 February 2012 WQ12S SE 100 Surface <0.5 <1 <1 <0.05 <0.005 0.002 <0.005 <0.01 <0.005 23.8 11.9 3.5 x 22.22 5.47 8.06 7.62 36.313/02/2012 February 2012 WQ12M SE 100 Midwater <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 23.8 11.9 x 19.87 5.52 7.93 6.26 36.713/02/2012 February 2012 WQ13S S 100 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 23.4 11.7 4 x 22.33 5.47 8.05 7.64 36.3113/02/2012 February 2012 WQ13M S 100 Midwater <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 0.006 23.4 11.7 x 18.53 5.53 7.89 9.86 36.613/02/2012 February 2012 WQ14S SW 100 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 21.8 10.9 4.5 x 22.25 5.47 8.08 7.69 36.313/02/2012 February 2012 WQ14M SW 100 Midwater <0.5 <1 <1 <0.05 0.005 0.01 0.015 <0.01 0.006 21.8 10.9 x 20.87 5.42 8.05 7.31 36.5313/02/2012 February 2012 WQ15S W 100 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 0.006 21.1 10.6 4.5 11.4 22.33 5.47 8.08 7.68 36.313/02/2012 February 2012 WQ15M W 100 Midwater <0.5 5 <1 <0.05 <0.005 0.008 0.008 <0.01 0.007 21.1 10.6 12.7 20.4 5.50 8.02 7.52 36.5313/02/2012 February 2012 WQ16S NW 100 Surface <0.5 1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 0.008 21.4 10.7 4 11.9 22.34 5.47 8.09 7.68 36.3113/02/2012 February 2012 WQ16M NW 100 Midwater <0.5 2 2 <0.05 <0.005 0.003 <0.005 <0.01 0.007 21.4 10.7 12.11 20.9 5.49 8.05 6.92 36.4514/02/2012 February 2012 WQ17S N 250 Surface 1 2 1 <0.05 <0.005 <0.002 <0.005 0.01 0.007 22.3 11.1 3.5 14.8 21.88 5.43 8.09 7.49 35.9814/02/2012 February 2012 WQ17M N 250 Midwater 1 7 63 <0.05 0.022 0.077 0.099 0.13 0.02 22.3 11.1 12.8 18.59 5.51 7.91 5.54 36.6714/02/2012 February 2012 WQ18S NE 250 Surface 1 <1 <1 <0.05 <0.005 0.003 <0.005 0.02 0.009 24.5 12.2 4 25.8 21.77 5.39 8.12 7.53 35.9514/02/2012 February 2012 WQ18M NE 250 Midwater <1 28 57 0.07 0.025 0.087 0.112 0.18 0.025 24.5 12.2 28.9 17 5.52 7.92 5.53 36.7514/02/2012 February 2012 WQ19S E 250 Surface <1 4 1 <0.05 <0.005 0.003 <0.005 0.01 0.011 25.1 12.5 3.5 x 21.62 5.35 8.11 7.46 35.414/02/2012 February 2012 WQ19M E 250 Midwater <1 30 97 <0.05 0.028 0.096 0.124 0.1 0.022 25.1 12.5 2.3 15.72 5.48 7.9 5.55 37.2813/02/2012 February 2012 WQ20S SE 250 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 24.5 12.3 4 x 22.21 5.47 8.05 7.65 36.313/02/2012 February 2012 WQ20M SE 250 Midwater <0.5 <1 <1 <0.05 <0.005 0.002 <0.005 <0.01 0.006 24.5 12.3 x 19.05 5.52 7.87 5.8 36.6213/02/2012 February 2012 WQ21S S 250 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 23.8 11.9 5 x 22.23 5.47 8.06 7.65 36.313/02/2012 February 2012 WQ21M S 250 Midwater <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 0.009 23.8 11.9 x 19.17 5.52 7.88 6.05 36.6513/02/2012 February 2012 WQ22S SW 250 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 23.2 11.6 4.5 x 22.25 5.47 8 7.65 36.313/02/2012 February 2012 WQ22M SW 250 Midwater <0.5 <1 <1 0.06 <0.005 <0.002 <0.005 0.06 0.007 23.2 11.6 x 20.24 5.50 7.99 6.64 36.5713/02/2012 February 2012 WQ23S W 250 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 0.011 20.0 10.0 4.5 x 22.25 5.49 8.77 7.66 36.313/02/2012 February 2012 WQ23M W 250 Midwater <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 0.005 20.0 10.0 x 20.68 5.50 8.02 7.08 36.5514/02/2012 February 2012 WQ24S NW 250 Surface <1 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 22.6 11.3 3.5 x 21.99 5.46 8.09 7.46 36.2414/02/2012 February 2012 WQ24M NW 250 Midwater <1 32 110 <0.05 0.05 0.113 0.163 0.14 0.023 22.6 11.3 7.2 15.26 5.54 7.85 5.17 36.8514/02/2012 February 2012 WQ25S NE 500 Surface 1 <1 <1 <0.05 <0.005 0.002 <0.005 <0.01 0.008 25.1 12.5 4 x 21.91 5.39 8.05 7.5 35.9414/02/2012 February 2012 WQ25M NE 500 Midwater <1 <1 <1 <0.05 0.007 0.038 0.045 0.06 0.014 25.1 12.5 x 17.44 5.52 7.91 5.5 36.7513/02/2012 February 2012 WQ26S SE 500 Surface <0.5 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 25.9 13.0 4 x 22.22 5.47 8.05 7.59 36.3113/02/2012 February 2012 WQ26M SE 500 Midwater <0.5 <1 <1 <0.05 <0.005 0.002 <0.005 <0.01 0.005 25.9 13.0 x 17 5.54 7.85 6.02 36.8713/02/2012 February 2012 WQ27S SW 500 Surface <0.5 <1 <1 <0.05 <0.005 0.011 0.011 <0.01 0.005 23.5 11.7 4.5 x 22.2 5.47 8.04 7.55 36.313/02/2012 February 2012 WQ27M SW 500 Midwater <0.5 <1 <1 <0.05 0.011 0.02 0.031 <0.01 0.01 23.5 11.7 x 18.5 5.52 7.94 6.36 36.9314/02/2012 February 2012 WQ28S NW 500 Surface <1 <1 1 <0.05 <0.005 <0.002 <0.005 0.02 0.006 18.7 9.4 4.5 x 21.96 5.47 8.06 7.49 36.2814/02/2012 February 2012 WQ28M NW 500 Midwater <1 1 4 <0.05 0.006 0.02 0.026 0.04 0.011 18.7 9.4 x 17.71 5.57 7.89 5.46 36.6214/02/2012 February 2012 WQ29S REFNE 2000 Surface <1 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 18.7 9.3 5 x 22.03 5.46 8.12 7.26 36.2214/02/2012 February 2012 WQ29M REFNE 2000 Midwater 2 <1 <1 <0.05 <0.005 0.032 0.032 0.05 0.014 18.7 9.3 x 19.89 5.49 8.07 6.88 36.4714/02/2012 February 2012 WQ30S REFNE 2000 Surface <1 <1 <1 <0.05 <0.005 <0.002 <0.005 <0.01 <0.005 25.0 12.5 4.5 10.2 22.02 5.43 8.11 7.71 3614/02/2012 February 2012 WQ30M REFNE 2000 Midwater <1 <1 <1 <0.05 0.009 0.049 0.058 0.05 0.015 25.0 12.5 9.3 15.43 5.55 7.88 5.37 36.8413/02/2012 February 2012 WQ31S REFSW 2000 Surface <0.5 <1 <1 <0.05 <0.005 0.006 0.006 <0.01 0.006 23.9 11.9 4.5 x 22.18 5.47 8.05 7.52 36.2713/02/2012 February 2012 WQ31M REFSW 2000 Midwater <0.5 <1 <1 <0.05 <0.005 0.004 <0.005 <0.01 0.005 23.9 11.9 x 19 5.52 7.78 6.33 36.4913/02/2012 February 2012 WQ32S REFSW 2000 Surface <0.5 <1 <1 <0.05 <0.005 0.005 0.005 <0.01 0.007 20.5 10.2 4 10 22.05 5.27 8.03 7.62 36.2713/02/2012 February 2012 WQ32M REFSW 2000 Midwater <0.5 <1 <1 <0.05 <0.005 0.006 0.006 <0.01 <0.005 20.5 10.2 10 20.01 5.47 7.9 7.24 36.3
April 2012
Sample date: Sampling period Sample ID DirectionDistance from
diffuser (m)Depth
Chlorophyll a (mg/m3)
Enterococci (CFU/100ml)
Faecal Coliforms
(CFU/100ml)
Organic Nitrogen as N (mg/L)
Ammonia as N (mg/L)
Nitrite + Nitrate as N (mg/L)
Inorganic Nitrogen as N (mg/L)
Total Nitrogen as N (mg/L)
Total Phosphorus as P (mg/L)
Depth at site (m)
Depth at mid water (m)
Sechi Disc Depth (m)
Turbidity (NTU)
Temperature (oC)
Conductivity (mS/cm)
pHDissolved oxygen (mg/L)
Salinity (‰)
23/04/2012 April 2012 WQ1S DIF 0 Surface <0.5 5 12 <0.05 <0.005 0.006 0.006 <0.05 0.008 20 10.0 4 2.8 22.14 5.48 8.46 7.11 36.3823/04/2012 April 2012 WQ1M DIF 0 Midwater <0.5 6 6 0.08 <0.005 0.007 0.007 0.09 0.013 20 10.0 2.6 21.88 5.50 8.45 6.79 36.5123/04/2012 April 2012 WQ2S DIF 0 Surface <0.5 8 17 <0.05 0.008 0.004 0.012 0.06 0.009 20.5 10.3 5 2.3 22.16 5.48 8.44 7.09 36.3823/04/2012 April 2012 WQ2M DIF 0 Midwater <0.5 5 11 0.1 <0.005 0.005 0.005 0.11 0.01 20.5 10.3 3 21.77 5.49 8.44 6.59 36.4123/04/2012 April 2012 WQ3S DIF 0 Surface <0.5 28 41 <0.05 0.018 0.004 0.022 <0.05 0.01 20 10.0 4.5 3.3 22.04 5.49 8.43 6.92 36.4123/04/2012 April 2012 WQ3M DIF 0 Midwater <0.5 78 200 0.07 0.068 0.01 0.078 0.15 0.018 20 10.0 2.9 22.01 5.49 8.44 6.68 36.4523/04/2012 April 2012 WQ4S DIF 0 Surface <0.5 5 43 <0.05 0.012 0.005 0.017 <0.05 0.007 23.5 11.8 3 2.4 22.13 5.48 8.43 7.11 36.3823/04/2012 April 2012 WQ4M DIF 0 Midwater <0.5 4 33 <0.05 <0.005 0.008 0.008 0.05 0.01 23.5 11.8 2.4 21.84 5.49 8.45 6.7 36.4723/04/2012 April 2012 WQ5S DIF 30 Surface <0.5 2 6 <0.05 <0.005 0.003 <0.005 0.05 0.009 23 11.5 4 2.4 22.15 5.48 8.44 7.07 36.3823/04/2012 April 2012 WQ5M DIF 30 Midwater <0.5 4 11 <0.05 <0.005 0.009 0.009 <0.05 0.01 23 11.5 2.5 21.88 5.50 8.44 6.68 36.523/04/2012 April 2012 WQ6S DIF 30 Surface <0.5 10 11 <0.05 <0.005 0.004 <0.005 <0.05 0.008 21.5 10.8 4.5 2.3 22.08 5.48 8.43 6.94 36.423/04/2012 April 2012 WQ6M DIF 30 Midwater <0.5 1 6 <0.05 0.009 0.013 0.022 <0.05 0.007 21.5 10.8 2.2 21.98 5.49 8.45 6.68 36.4123/04/2012 April 2012 WQ7S DIF 30 Surface <0.5 12 12 <0.05 0.006 0.005 0.011 <0.05 0.008 23.5 11.8 4.5 2.5 22.15 5.48 8.43 7.1 36.3723/04/2012 April 2012 WQ7M DIF 30 Midwater 1 <1 9 <0.05 0.009 0.005 0.014 0.05 0.009 23.5 11.8 2.3 21.85 5.50 8.45 6.71 36.5123/04/2012 April 2012 WQ8S DIF 30 Surface <0.5 11 58 <0.05 0.005 0.003 0.008 <0.05 0.008 21.5 10.8 4 2.5 22.16 5.48 8.43 7.1 36.3723/04/2012 April 2012 WQ8M DIF 30 Midwater <0.5 26 69 <0.05 0.007 0.004 0.011 0.06 0.01 21.5 10.8 2.2 21.81 5.48 8.44 6.65 36.3423/04/2012 April 2012 WQ9S N 100 Surface <0.5 2 4 <0.05 <0.005 0.003 <0.005 0.05 0.009 24 12.0 3.5 2.5 22.16 5.48 8.43 7.1 36.5523/04/2012 April 2012 WQ9M N 100 Midwater <0.5 5 6 0.05 0.006 0.01 0.016 0.07 0.009 24 12.0 2.7 21.84 5.50 8.4 6.68 36.5523/04/2012 April 2012 WQ10S NE 100 Surface <0.5 5 5 <0.05 <0.005 0.006 0.006 <0.05 0.007 24 12.0 4 2.4 22.14 5.48 8.44 7.07 36.3923/04/2012 April 2012 WQ10M NE 100 Midwater <0.5 <1 5 <0.05 <0.005 0.008 0.008 <0.05 0.008 24 12.0 2.5 21.87 5.40 8.45 6.67 36.5223/04/2012 April 2012 WQ11S E 100 Surface <0.5 7 9 <0.05 <0.005 0.004 <0.005 <0.05 0.008 24 12.0 4.5 2.4 22.16 5.48 8.44 7.1 36.3723/04/2012 April 2012 WQ11M E 100 Midwater <0.5 1 2 <0.05 <0.005 <0.002 <0.005 <0.05 0.008 24 12.0 2.3 21.96 5.48 8.44 6.64 36.3923/04/2012 April 2012 WQ12S SE 100 Surface <0.5 3 7 0.09 <0.005 <0.002 <0.005 0.09 0.008 24 12.0 4.5 2.3 22.15 5.48 8.43 7.12 36.3423/04/2012 April 2012 WQ12M SE 100 Midwater <0.5 5 25 0.05 <0.005 0.01 0.01 0.06 0.01 24 12.0 2.2 21.94 5.50 8.45 6.7 36.4223/04/2012 April 2012 WQ13S S 100 Surface <0.5 6 34 0.07 0.008 0.004 0.012 0.08 0.013 23.5 11.8 4 2.1 22.15 5.48 8.44 7 36.3723/04/2012 April 2012 WQ13M S 100 Midwater <0.5 4 77 <0.05 <0.005 0.005 0.005 <0.05 0.01 23.5 11.8 2.2 22.04 5.48 8.45 6.7 36.4123/04/2012 April 2012 WQ14S SW 100 Surface <0.5 2 9 <0.05 <0.005 <0.002 <0.005 <0.05 0.008 21 10.5 3.5 2.6 22.17 5.48 8.44 7.09 36.3623/04/2012 April 2012 WQ14M SW 100 Midwater <0.5 190 400 0.18 0.017 0.004 0.021 0.2 0.062 21 10.5 2.3 21.99 5.49 8.45 6.73 36.4523/04/2012 April 2012 WQ15S W 100 Surface <0.5 4 24 <0.05 <0.005 0.003 <0.005 0.05 0.008 21 10.5 4.5 2.8 22.17 5.48 8.44 7.18 36.3723/04/2012 April 2012 WQ15M W 100 Midwater <0.5 75 200 0.06 0.134 0.02 0.154 0.21 0.024 21 10.5 3 21.81 5.50 8.45 6.59 36.4923/04/2012 April 2012 WQ16S NW 100 Surface <0.5 4 8 <0.05 <0.005 0.002 <0.005 0.05 0.008 22 11.0 4 2.9 22.15 5.48 8.43 7.17 36.3723/04/2012 April 2012 WQ16M NW 100 Midwater <0.5 <1 5 0.05 <0.005 0.009 0.009 0.06 0.009 22 11.0 3.4 21.75 5.52 8.44 6.51 36.4123/04/2012 April 2012 WQ17S N 250 Surface <0.5 4 5 <0.05 <0.005 0.008 0.008 <0.05 0.008 22.8 11.4 4 3.7 22.16 5.48 8.43 6.93 36.3923/04/2012 April 2012 WQ17M N 250 Midwater <0.5 7 24 0.06 <0.005 <0.002 <0.005 0.06 0.009 22.8 11.4 3.3 21.84 5.50 8.44 6.64 36.5223/04/2012 April 2012 WQ18S NE 250 Surface <0.5 8 7 <0.05 <0.005 0.004 <0.005 <0.05 0.009 24.8 12.4 4 2.4 22.14 5.48 8.43 7.07 36.3923/04/2012 April 2012 WQ18M NE 250 Midwater <0.5 3 19 <0.05 0.046 0.003 0.049 <0.05 <0.005 24.8 12.4 2.5 21.84 5.49 8.45 6.65 36.423/04/2012 April 2012 WQ19S E 250 Surface <0.5 3 6 <0.05 <0.005 0.005 0.005 <0.05 0.008 25.5 12.8 4 2.3 22.17 5.48 8.44 7.13 36.3323/04/2012 April 2012 WQ19M E 250 Midwater <0.5 <1 5 0.06 <0.005 0.003 <0.005 0.06 0.011 25.5 12.8 2.2 22.04 5.49 8.44 6.67 36.4223/04/2012 April 2012 WQ20S SE 250 Surface <0.5 4 2 <0.05 <0.005 <0.002 <0.005 <0.05 0.008 25.5 12.8 5 1.9 22.74 5.47 8.45 7.12 36.3323/04/2012 April 2012 WQ20M SE 250 Midwater <0.5 4 34 <0.05 <0.005 0.002 <0.005 0.05 0.008 25.5 12.8 2.1 21.83 5.50 8.45 6.62 36.5123/04/2012 April 2012 WQ21S S 250 Surface <1.0 3 36 0.06 <0.005 0.004 <0.005 0.06 0.009 25 12.5 5.5 1.8 22.18 5.47 8.47 7.42 36.323/04/2012 April 2012 WQ21M S 250 Midwater <1.0 2 7 <0.05 <0.005 0.004 <0.005 <0.05 0.008 25 12.5 1.9 21.87 5.49 8.46 6.69 36.4723/04/2012 April 2012 WQ22S SW 250 Surface <1.0 8 9 <0.05 0.006 0.003 0.009 0.05 0.008 22 11.0 6 1.5 22.2 5.48 8.45 7.01 36.3623/04/2012 April 2012 WQ22M SW 250 Midwater 1 5 28 0.1 <0.005 0.002 <0.005 0.1 0.008 22 11.0 2 21.85 5.50 8.46 6.71 36.5123/04/2012 April 2012 WQ23S W 250 Surface <1.0 1 2 <0.05 0.007 0.004 0.011 0.06 0.007 23.5 11.8 4 2.2 22.16 5.48 8.44 7.14 36.3723/04/2012 April 2012 WQ23M W 250 Midwater <1.0 40 150 <0.05 0.068 0.011 0.079 0.08 0.013 23.5 11.8 3.6 22.48 5.51 8.44 6.51 36.5823/04/2012 April 2012 WQ24S NW 250 Surface <1.0 4 8 0.06 0.009 0.002 0.011 0.07 0.008 23 11.5 4 2.6 22.14 5.48 8.43 7.07 36.323/04/2012 April 2012 WQ24M NW 250 Midwater <1.0 <1 4 0.06 <0.005 0.011 0.011 0.07 0.01 23 11.5 3.1 21.86 5.51 8.43 6.42 36.5723/04/2012 April 2012 WQ25S NE 500 Surface <1.0 1 7 <0.05 <0.005 0.004 <0.005 <0.05 0.007 25 12.5 4 2.7 22.12 5.48 8.43 6.99 36.4523/04/2012 April 2012 WQ25M NE 500 Midwater <1.0 3 2 0.07 <0.005 0.003 <0.005 0.07 0.011 25 12.5 2.2 21.99 5.48 8.45 6.78 36.4423/04/2012 April 2012 WQ26S SE 500 Surface <1.0 3 3 <0.05 0.068 0.005 0.073 0.09 0.008 26 13.0 5 2.3 22.2 5.48 8.4 7.08 36.3323/04/2012 April 2012 WQ26M SE 500 Midwater <1.0 3 35 <0.05 <0.005 0.002 <0.005 <0.05 0.006 26 13.0 1.8 22.17 5.48 8.46 6.82 36.3723/04/2012 April 2012 WQ27S SW 500 Surface <1.0 <1 31 <0.05 0.008 0.004 0.012 <0.05 0.008 23.4 11.7 4.5 1.7 22.18 5.47 8.33 7.05 36.3323/04/2012 April 2012 WQ27M SW 500 Midwater <1.0 4 1 0.06 0.007 0.002 0.009 0.07 0.008 23.4 11.7 1.2 21.85 5.50 8.44 6.75 36.5723/04/2012 April 2012 WQ28S NW 500 Surface <1.0 2 7 <0.05 <0.005 0.004 <0.005 <0.05 0.008 19 9.5 5 4.2 22.15 5.48 8.43 7.09 36.3823/04/2012 April 2012 WQ28M NW 500 Midwater <1.0 4 8 0.06 0.006 0.017 0.023 0.08 0.012 19 9.5 3.9 21.95 5.51 8.43 6.41 36.5523/04/2012 April 2012 WQ29S REFNE 2000 Surface <1.0 2 8 <0.05 <0.005 0.005 0.005 <0.05 0.009 19 9.5 5 2.4 22.22 5.48 8.42 7.04 36.3623/04/2012 April 2012 WQ29M REFNE 2000 Midwater <1.0 <1 9 <0.05 <0.005 0.013 0.013 <0.05 0.009 19 9.5 5.7 21.24 5.40 8.43 6.29 36.5523/04/2012 April 2012 WQ30S REFNE 2000 Surface 2 7 10 <0.05 <0.005 0.007 0.007 <0.05 0.011 25 12.5 4 2.3 22.17 5.48 8.43 7.03 36.3323/04/2012 April 2012 WQ30M REFNE 2000 Midwater <1.0 2 3 <0.05 <0.005 0.005 0.005 <0.05 0.01 25 12.5 2.2 21.82 5.50 8.44 6.72 36.523/04/2012 April 2012 WQ31S REFSW 2000 Surface <1.0 8 17 0.08 0.039 0.006 0.045 0.12 0.009 24 12.0 5 1 22.3 5.46 8.39 7.1 36.223/04/2012 April 2012 WQ31M REFSW 2000 Midwater <1.0 7 27 0.08 0.016 0.004 0.02 0.1 0.008 24 12.0 1.2 21.8 5.49 8.41 6.74 36.423/04/2012 April 2012 WQ32S REFSW 2000 Surface <1.0 2 3 0.18 0.009 0.005 0.014 0.19 0.009 21 10.5 5 0.9 22.23 5.47 8.23 7.19 36.3223/04/2012 April 2012 WQ32M REFSW 2000 Midwater <1.0 19 54 0.27 0.067 0.009 0.076 0.35 0.034 21 10.5 1.7 21.99 5.51 8.42 6.52 36.52
NB1: Where data are preceded by a less than sign (<), the concentration was below the limit of reporting for that analysis.
June 2012
Sample date: Sampling period Sample ID DirectionDistance from
diffuser (m)Depth
Chlorophyll a (mg/m3)
Enterococci (CFU/100ml)
Faecal Coliforms
(CFU/100ml)
Organic Nitrogen as N (mg/L)
Ammonia as N (mg/L)
Nitrite + Nitrate as N (mg/L)
Inorganic Nitrogen as N (mg/L)
Total Nitrogen as N (mg/L)
Total Phosphorus as P (mg/L)
Depth at site (m)
Depth at mid water (m)
Sechi Disc Depth (m)
Turbidity (NTU)
Temperature (oC)
Conductivity (mS/cm)
pHDissolved oxygen (mg/L)
Salinity (‰)
27/06/2012 June 2012 WQ1S DIF 0 Surface <0.5 170 200 0.19 0.074 0.037 0.111 0.3 0.034 19.5 9.8 3 2.1 17 5.89 8.21 7.6 38.427/06/2012 June 2012 WQ1M DIF 0 Midwater <0.5 42 130 0.42 0.079 0.039 0.118 0.54 0.027 19.5 9.8 1.9 16.9 5.92 8.21 7.6 38.627/06/2012 June 2012 WQ2S DIF 0 Surface <0.5 170 230 0.23 0.069 0.037 0.106 0.34 0.023 21.2 10.6 3 4.6 17 5.88 8.23 7.6 38.527/06/2012 June 2012 WQ2M DIF 0 Midwater <0.5 130 190 0.1 0.038 0.038 0.076 0.18 0.016 21.2 10.6 1.8 17 5.90 8.24 7.7 38.527/06/2012 June 2012 WQ3S DIF 0 Surface <0.5 160 160 0.2 0.068 0.037 0.105 0.3 0.013 22.2 11.1 3 2.5 17 5.90 8.23 7.5 38.527/06/2012 June 2012 WQ3M DIF 0 Midwater <0.5 200 200 0.28 0.153 0.037 0.19 0.47 0.031 22.2 11.1 2.1 17 5.91 8.21 8.3 38.627/06/2012 June 2012 WQ4S DIF 0 Surface <0.5 130 190 0.15 0.054 0.037 0.091 0.24 0.026 23 11.5 2.5 2.1 17 5.91 8.24 8.5 38.627/06/2012 June 2012 WQ4M DIF 0 Midwater <0.5 4 9 <0.05 0.01 0.036 0.046 0.04 0.008 23 11.5 1.1 17 5.92 8.24 7.7 38.727/06/2012 June 2012 WQ5S N 30 Surface <0.5 110 210 0.14 0.055 0.039 0.094 0.23 0.017 21.4 10.7 3 2.2 16.9 5.91 8.22 8.4 38.627/06/2012 June 2012 WQ5M N 30 Midwater <0.5 11 43 0.1 0.015 0.038 0.053 0.15 0.011 21.4 10.7 2.7 17 5.90 8.23 7.9 38.627/06/2012 June 2012 WQ6S E 30 Surface <0.5 120 160 0.18 0.065 0.038 0.103 0.28 0.024 21.4 10.7 2 2.2 17 5.91 8.24 7.9 38.627/06/2012 June 2012 WQ6M E 30 Midwater <0.5 130 170 0.1 0.069 0.038 0.107 0.21 0.022 21.4 10.7 1.5 17 5.90 8.24 7.6 38.627/06/2012 June 2012 WQ7S S 30 Surface <0.5 160 180 0.22 0.064 0.037 0.101 0.32 0.034 23.2 11.6 2.5 2.2 17 5.91 8.24 7.6 38.627/06/2012 June 2012 WQ7M S 30 Midwater <0.5 6 11 0.11 0.014 0.036 0.05 0.16 0.006 23.2 11.6 1.9 17 5.91 8.22 7.7 38.627/06/2012 June 2012 WQ8S W 30 Surface <0.5 4 1 0.11 0.012 0.038 0.05 0.16 0.014 20.8 10.4 2.5 2.8 17 5.91 8.24 8.2 38.627/06/2012 June 2012 WQ8M W 30 Midwater <0.5 4 4 <0.05 0.016 0.037 0.053 0.1 0.014 20.8 10.4 1.4 17 5.92 8.2 7.7 38.727/06/2012 June 2012 WQ9S N 100 Surface <0.5 42 130 0.09 0.04 0.038 0.078 0.17 0.013 22.8 11.4 2.5 1.3 17 5.91 8.22 7.9 38.627/06/2012 June 2012 WQ9M N 100 Midwater <0.5 25 79 0.12 0.012 0.044 0.056 0.18 0.009 22.8 11.4 1.4 17 5.91 8.22 9.6 38.627/06/2012 June 2012 WQ10S E 100 Surface <0.5 170 250 0.09 0.08 0.037 0.117 0.21 0.024 24 12.0 3 1.3 17 5.91 8.24 7.5 38.627/06/2012 June 2012 WQ10M E 100 Midwater <0.5 60 180 0.22 0.015 0.038 0.053 0.27 0.03 24 12.0 1.7 17 5.93 8.24 7.7 38.727/06/2012 June 2012 WQ11S E 100 Surface <0.5 200 210 0.18 0.044 0.041 0.085 0.26 0.036 24 12.0 2 2.3 17 5.92 8.23 7.7 38.627/06/2012 June 2012 WQ11M E 100 Midwater <0.5 130 150 <0.05 0.015 0.037 0.052 0.08 0.017 24 12.0 1.1 17 5.92 8.23 8.2 38.727/06/2012 June 2012 WQ12S E 100 Surface <0.5 2 1 0.06 <0.005 0.038 0.038 0.1 0.016 24 12.0 3 1 17.1 5.91 8.26 7.4 38.627/06/2012 June 2012 WQ12M E 100 Midwater <0.5 7 7 0.06 <0.005 0.037 0.037 0.1 0.014 24 12.0 1.4 17.1 5.91 8.23 7.8 38.627/06/2012 June 2012 WQ13S S 100 Surface <0.5 7 1 <0.05 <0.005 0.036 0.036 0.08 0.014 23.5 11.8 3 0.9 17.1 5.92 8.25 7.5 38.727/06/2012 June 2012 WQ13M S 100 Midwater <0.5 5 <1 0.11 <0.005 0.036 0.036 0.15 0.016 23.5 11.8 1.1 17.1 5.92 8.24 7.9 38.727/06/2012 June 2012 WQ14S S 100 Surface <0.5 <1 <1 0.05 <0.005 0.037 0.037 0.09 0.013 22 11.0 2.5 2.9 17.1 5.91 8.24 7.5 38.727/06/2012 June 2012 WQ14M S 100 Midwater <0.5 4 2 <0.05 <0.005 0.037 0.037 0.06 0.008 22 11.0 1.3 17 5.93 8.24 7.8 38.727/06/2012 June 2012 WQ15S W 100 Surface <0.5 11 <1 <0.05 <0.005 0.035 0.035 0.06 0.008 21.6 10.8 2.5 2.1 17.1 5.91 8.25 7.6 38.627/06/2012 June 2012 WQ15M W 100 Midwater <0.5 1 <1 0.06 <0.005 0.036 0.036 0.1 0.012 21.6 10.8 1.2 17 5.93 8.24 7.8 38.627/06/2012 June 2012 WQ16S W 100 Surface <0.5 82 140 0.1 0.069 0.036 0.105 0.2 0.022 22 11.0 2.5 2.9 17.1 5.90 8.24 7.5 38.527/06/2012 June 2012 WQ16M W 100 Midwater <0.5 78 120 0.06 0.046 0.036 0.082 0.14 0.012 22 11.0 1.5 17 5.92 8.24 7.8 38.627/06/2012 June 2012 WQ17S N 250 Surface <0.5 72 110 0.05 0.044 0.036 0.08 0.13 0.017 22.5 11.3 2.5 1.2 17 5.91 8.24 7.5 38.627/06/2012 June 2012 WQ17M N 250 Midwater <0.5 19 32 <0.05 0.011 0.037 0.048 0.06 0.009 22.5 11.3 1.2 16.9 5.92 8.23 7.7 38.728/06/2012 June 2012 WQ18S E 250 Surface <0.5 110 150 0.08 0.06 0.042 0.102 0.18 0.032 24 12.0 2.5 1.7 16.7 5.90 8.25 7.4 38.528/06/2012 June 2012 WQ18M E 250 Midwater <0.5 34 42 0.12 <0.005 0.039 0.039 0.16 0.013 24 12.0 2.2 16.8 5.92 8.23 7.9 38.627/06/2012 June 2012 WQ19S E 250 Surface <0.5 <1 <1 0.1 <0.005 0.036 0.036 0.14 0.012 24.8 12.4 3 1 17.1 5.92 8.24 7.5 38.727/06/2012 June 2012 WQ19M E 250 Midwater <0.5 1 <1 <0.05 0.006 0.037 0.043 0.06 0.011 24.8 12.4 0.7 17.1 5.91 8.23 7.9 38.728/06/2012 June 2012 WQ20S E 250 Surface <0.5 120 140 0.1 0.045 0.038 0.083 0.18 0.022 24 12.0 2.5 1 16.8 5.89 8.26 7.4 38.428/06/2012 June 2012 WQ20M E 250 Midwater <0.5 80 26 0.1 0.013 0.04 0.053 0.15 0.015 24 12.0 1.3 16.9 5.92 8.24 7.5 38.727/06/2012 June 2012 WQ21S S 250 Surface <0.5 39 120 <0.05 0.038 0.036 0.074 0.12 0.013 23.5 11.8 1.9 17 5.90 8.24 7.5 38.627/06/2012 June 2012 WQ21M S 250 Midwater <0.5 5 28 0.05 0.009 0.038 0.047 0.1 0.014 23.5 11.8 1.4 17 5.92 8.24 7.5 38.728/06/2012 June 2012 WQ22S S 250 Surface <0.5 110 130 0.07 0.033 0.038 0.071 0.14 0.02 21.5 10.8 3 0.6 16.8 5.89 8.24 7.4 38.428/06/2012 June 2012 WQ22M S 250 Midwater <0.5 89 46 <0.05 <0.005 0.038 0.038 0.07 0.008 21.5 10.8 0.6 17 5.92 8.24 7.9 38.727/06/2012 June 2012 WQ23S W 250 Surface <0.5 2 <1 0.08 <0.005 0.035 0.035 0.11 0.015 19 9.5 3 0.7 17.1 5.91 8.24 7.5 38.627/06/2012 June 2012 WQ23M W 250 Midwater <0.5 1 1 <0.05 <0.005 0.034 0.034 0.08 0.016 19 9.5 1.1 17 5.93 8.23 7.7 38.728/06/2012 June 2012 WQ24S W 250 Surface <0.5 51 130 0.06 0.026 0.039 0.065 0.12 0.018 22 11.0 2.5 1.7 16.8 5.90 8.24 7.4 38.528/06/2012 June 2012 WQ24M W 250 Midwater <0.5 120 84 <0.05 <0.005 0.038 0.038 0.08 0.014 22 11.0 1.5 16.8 5.92 8.23 7.6 38.727/06/2012 June 2012 WQ25S E 500 Surface <0.5 120 130 <0.05 0.023 0.031 0.054 0.09 0.018 25.7 12.9 2.5 1.6 17 5.92 8.23 7.5 38.727/06/2012 June 2012 WQ25M E 500 Midwater <0.5 14 44 <0.05 <0.005 0.034 0.034 0.02 <0.005 25.7 12.9 0.9 17 5.93 8.24 7.6 38.728/06/2012 June 2012 WQ26S E 500 Surface <0.5 130 120 0.1 0.02 0.038 0.058 0.16 0.016 26 13.0 3 0.7 16.9 5.91 8.24 7.3 38.628/06/2012 June 2012 WQ26M E 500 Midwater <0.5 11 14 0.07 <0.005 0.04 0.04 0.11 0.009 26 13.0 1.5 16.9 5.93 8.23 7.6 38.627/06/2012 June 2012 WQ27S S 500 Surface <0.5 2 1 <0.05 <0.005 0.034 0.034 0.02 0.011 24 12.0 3 0.9 17.1 5.92 8.24 7.6 38.727/06/2012 June 2012 WQ27M S 500 Midwater <0.5 1 1 <0.05 <0.005 0.029 0.029 0.06 0.009 24 12.0 1.02 17.1 5.92 8.24 7.7 38.728/06/2012 June 2012 WQ28S W 500 Surface <0.5 49 92 0.07 0.021 0.038 0.059 0.13 0.015 18.3 9.2 2.5 1.3 16.8 5.90 8.25 7.4 38.528/06/2012 June 2012 WQ28M W 500 Midwater <0.5 22 120 0.09 0.035 0.037 0.072 0.16 0.014 18.3 9.2 1.4 16.8 5.91 8.24 7.7 38.527/06/2012 June 2012 WQ29S REFNE 2000 Surface <0.5 70 140 0.06 0.02 0.033 0.053 0.11 0.015 19.7 9.9 2.5 0.7 16.8 5.91 8.25 7.7 38.227/06/2012 June 2012 WQ29M REFNE 2000 Midwater <0.5 45 150 <0.05 0.024 0.039 0.063 0.08 0.017 19.7 9.9 1 16.7 5.93 8.24 8.1 38.728/06/2012 June 2012 WQ30S REFNE 2000 Surface <0.5 16 22 0.31 0.009 0.044 0.053 0.36 0.017 25 12.5 2 0.9 16.6 5.93 8.21 7.5 38.528/06/2012 June 2012 WQ30M REFNE 2000 Midwater <0.5 13 36 0.26 0.015 0.052 0.067 0.33 0.016 25 12.5 1.4 16.5 5.93 8.18 7.8 38.627/06/2012 June 2012 WQ31S REFSW 2000 Surface <0.5 <1 1 <0.05 <0.005 0.036 0.036 0.04 0.012 24.7 12.4 3 0.9 16.8 5.90 8.25 7.8 38.527/06/2012 June 2012 WQ31M REFSW 2000 Midwater <0.5 2 1 0.05 <0.005 0.039 0.039 0.09 0.015 24.7 12.4 0.7 16.8 5.90 8.25 7.8 38.528/06/2012 June 2012 WQ32S REFSW 2000 Surface <0.5 2 <1 0.07 <0.005 0.039 0.039 0.11 0.012 20 10.0 2 0.7 16.6 5.89 8.24 7.4 38.428/06/2012 June 2012 WQ32M REFSW 2000 Midwater <0.5 2 <1 <0.05 <0.005 0.039 0.039 0.01 0.015 20 10.0 1.5 16.7 5.92 8.23 8 38.6
NB1: Where data are preceded by a less than sign (<), the concentration was below the limit of reporting for that analysis.
NB2: Data in italics were not included in statistical analyses due to suspected equipment malfunction.
October 2012
Sample date: Sampling period Sample ID DirectionDistance from
diffuser (m)Depth
Chlorophyll a (mg/m3)
Enterococci (CFU/100ml)
Faecal Coliforms
(CFU/100ml)
Organic Nitrogen as N (mg/L)
Ammonia as N (mg/L)
Nitrite + Nitrate as N (mg/L)
Inorganic Nitrogen as N (mg/L)
Total Nitrogen as N (mg/L)
Total Phosphorus as P (mg/L)
Depth at site (m)
Depth at mid water (m)
Sechi Disc Depth (m)
Turbidity (NTU)
Temperature (oC)
Conductivity (mS/cm)
pHDissolved oxygen (mg/L)
Salinity (‰)
15/10/2012 October 2012 WQ1S DIF 0 Surface 1 57 480 0.3 0.062 0.006 0.068 0.37 0.026 23 11.5 2.5 <2 17.7 5.81 8.33 11.44 32.415/10/2012 October 2012 WQ1M DIF 0 Midwater 2 20 88 0.2 0.012 0.002 0.014 0.21 0.019 23 11.5 <2 18 5.82 8.34 11.15 32.115/10/2012 October 2012 WQ2S DIF 0 Surface 3 72 350 0.14 0.111 0.004 0.115 0.25 0.025 21.9 11.0 2.5 <2 18.1 5.78 8.34 11.47 31.915/10/2012 October 2012 WQ2M DIF 0 Midwater 2 43 210 0.11 0.072 0.004 0.076 0.19 0.024 21.9 11.0 <2 18 5.77 8.33 11.23 31.915/10/2012 October 2012 WQ3S DIF 0 Surface 2 120 560 0.19 0.09 0.003 0.093 0.28 0.023 19.5 9.3 2 <2 18.1 5.69 8.34 11.61 31.615/10/2012 October 2012 WQ3M DIF 0 Midwater <0.5 52 210 0.18 0.041 <0.002 0.041 0.22 0.023 19.5 9.3 <2 18 5.80 8.33 11.43 32.115/10/2012 October 2012 WQ4S DIF 0 Surface 1 62 230 0.11 0.088 0.003 0.091 0.2 0.024 21.4 10.7 2 <2 18.1 5.79 8.33 11.48 31..915/10/2012 October 2012 WQ4M DIF 0 Midwater 2 32 120 0.12 0.036 <0.002 0.036 0.16 0.022 21.4 10.7 <2 18 5.79 8.34 11.65 32.115/10/2012 October 2012 WQ5S N 30 Surface 2 41 260 0.14 0.036 0.003 0.039 0.18 0.022 21.8 10.9 2.5 <2 18.2 5.78 8.33 11.95 3215/10/2012 October 2012 WQ5M N 30 Midwater 2 27 210 0.22 0.021 0.003 0.024 0.24 0.017 21.8 10.9 <2 18.1 5.79 8.34 11.82 32.116/10/2012 October 2012 WQ6S E 30 Surface 2 95 240 0.5 0.058 0.004 0.062 0.56 0.03 22.4 11.0 2 <2 18.1 5.78 8.34 11.65 3216/10/2012 October 2012 WQ6M E 30 Midwater 1 51 180 0.09 0.029 <0.002 0.029 0.12 0.018 22.4 11.0 <2 18 5.83 8.35 11.58 32.215/10/2012 October 2012 WQ7S S 30 Surface 2 67 230 0.17 0.06 0.002 0.062 0.23 0.04 24 12.0 2.5 <2 18.1 5.80 8.34 11.59 31.915/10/2012 October 2012 WQ7M S 30 Midwater 2 33 170 0.1 0.026 <0.002 0.026 0.13 0.018 24 12.0 <2 18 5.79 8.3 11.54 3216/10/2012 October 2012 WQ8S W 30 Surface 3 110 260 0.13 0.054 0.003 0.057 0.19 0.019 22.1 11.0 2 <2 18 5.80 8.33 11.65 3216/10/2012 October 2012 WQ8M W 30 Midwater 2 150 250 0.17 0.036 0.003 0.039 0.21 0.025 22.1 11.0 <2 18 5.82 8.37 11.54 32.215/10/2012 October 2012 WQ9S N 100 Surface 2 <1 5 0.08 <0.005 <0.002 <0.005 0.08 0.017 22.6 11.3 2.5 <2 18.3 5.79 8.32 11.78 32.215/10/2012 October 2012 WQ9M N 100 Midwater 1 4 2 0.18 <0.005 0.002 <0.005 0.18 0.018 22.6 11.3 <2 18.1 5.78 8.32 12.23 3215/10/2012 October 2012 WQ10S E 100 Surface 3 87 250 0.14 0.102 0.003 0.105 0.25 0.033 23.6 11.8 2.5 <2 18.1 5.77 8.33 11.83 31.915/10/2012 October 2012 WQ10M E 100 Midwater 2 52 200 0.11 0.048 0.002 0.05 0.16 0.018 23.6 11.8 <2 18.1 5.79 8.34 11.62 3215/10/2012 October 2012 WQ11S E 100 Surface 2 110 230 0.14 0.02 <0.002 0.02 0.16 0.022 24.8 12.4 2.5 <2 18.2 5.79 8.31 11.49 3215/10/2012 October 2012 WQ11M E 100 Midwater <0.5 41 81 0.11 0.007 0.002 0.009 0.12 0.016 24.8 12.4 <2 18.2 5.79 8.29 11.74 3215/10/2012 October 2012 WQ12S E 100 Surface 2 57 220 0.11 0.099 0.003 0.102 0.21 0.026 23.6 11.8 2.5 <2 18.2 5.78 8.33 11.73 31.915/10/2012 October 2012 WQ12M E 100 Midwater 3 42 170 0.15 0.044 0.003 0.047 0.2 0.026 23.6 11.8 <2 18.2 5.79 8.33 11.63 3215/10/2012 October 2012 WQ13S S 100 Surface 2 260 190 0.17 0.048 0.004 0.052 0.22 0.044 23.6 11.8 2.5 <2 18.2 5.82 8.31 11.78 3215/10/2012 October 2012 WQ13M S 100 Midwater 2 67 240 0.17 0.023 <0.002 0.023 0.19 0.03 23.6 11.8 <2 18.1 5.79 8.31 12.16 3215/10/2012 October 2012 WQ14S S 100 Surface 2 1000 540 0.17 0.084 0.002 0.086 0.26 0.042 23.6 11.8 2.5 <2 18.2 5.77 8.31 11.66 31.915/10/2012 October 2012 WQ14M S 100 Midwater 1 79 270 0.09 0.025 0.003 0.028 0.12 0.022 23.6 11.8 <2 18 5.80 8.3 11.42 32.115/10/2012 October 2012 WQ15S W 100 Surface 2 62 300 0.12 0.062 0.003 0.065 0.18 0.023 21.4 10.7 2.5 <2 18.1 5.78 8.33 12.09 32.215/10/2012 October 2012 WQ15M W 100 Midwater <0.5 32 250 0.11 0.046 <0.002 0.046 0.16 0.019 21.4 10.7 <2 18 5.84 8.3 11.61 32.115/10/2012 October 2012 WQ16S W 100 Surface 2 52 230 0.11 0.099 0.002 0.101 0.21 0.022 20 10.0 3 <2 18.3 5.77 8.31 11.48 3215/10/2012 October 2012 WQ16M W 100 Midwater <0.5 76 230 0.11 0.09 0.002 0.092 0.2 0.016 20 10.0 <2 18 5.80 8.3 10.87 3215/10/2012 October 2012 WQ17S N 250 Surface 2 <1 <1 0.07 <0.005 <0.002 <0.005 0.07 0.016 22.9 11.5 2.5 <2 18.3 5.79 8.3 11.97 3215/10/2012 October 2012 WQ17M N 250 Midwater 2 1 5 0.07 <0.005 <0.002 <0.005 0.07 0.008 22.9 11.5 <2 18 5.79 8.31 12.3 3215/10/2012 October 2012 WQ18S E 250 Surface <0.5 34 52 0.11 0.06 0.003 0.063 0.17 0.018 23.9 12.0 2.5 <2 18.3 5.79 8.33 11.12 3215/10/2012 October 2012 WQ18M E 250 Midwater <0.5 11 9 0.11 0.025 0.002 0.027 0.14 0.014 23.9 12.0 <2 18.1 5.79 8.3 11.45 3215/10/2012 October 2012 WQ19S E 250 Surface 1 <1 <1 0.08 <0.005 <0.002 <0.005 0.08 0.006 25.5 12.7 2.5 <2 18.3 5.79 8.33 12.1 3215/10/2012 October 2012 WQ19M E 250 Midwater 1 <1 <1 0.12 <0.005 <0.002 <0.005 0.12 0.009 25.5 12.7 <2 18.3 5.78 8.32 12.17 3215/10/2012 October 2012 WQ20S E 250 Surface <0.5 16 66 0.1 0.077 0.002 0.079 0.18 0.014 24.2 12.1 2.5 <2 18.3 5.78 8.31 11.04 31.915/10/2012 October 2012 WQ20M E 250 Midwater 1 16 32 0.09 0.028 0.004 0.032 0.12 0.011 24.2 12.1 <2 18 5.79 8.33 11.33 32.115/10/2012 October 2012 WQ21S S 250 Surface 3 <1 <1 0.09 <0.005 <0.002 <0.005 0.09 0.006 24 12.0 2.5 <2 18.2 5.78 8.31 12.04 3215/10/2012 October 2012 WQ21M S 250 Midwater <0.5 <1 <1 0.11 <0.005 0.003 <0.005 0.11 0.012 24 12.0 <2 18 5.79 8.3 12.2 3215/10/2012 October 2012 WQ22S S 250 Surface <0.5 65 54 0.13 0.063 0.003 0.066 0.2 0.022 22 11.0 2.5 <2 18.3 5.75 8.31 11.24 31.915/10/2012 October 2012 WQ22M S 250 Midwater <0.5 45 34 0.14 0.023 <0.002 0.023 0.16 0.015 22 11.0 <2 18.1 5.79 8.32 11.29 32.115/10/2012 October 2012 WQ23S W 250 Surface 2 8 2 0.1 <0.005 0.004 <0.005 0.1 0.008 19.8 9.4 2.5 <2 18.3 5.79 8.31 11.69 3215/10/2012 October 2012 WQ23M W 250 Midwater <0.5 24 59 0.09 0.008 <0.002 0.008 0.1 0.01 19.8 9.4 <2 18 5.79 8.33 11.45 3215/10/2012 October 2012 WQ24S W 250 Surface <0.5 2 <1 0.08 <0.005 <0.002 <0.005 0.08 0.007 22 11.0 2.5 <2 18.6 5.79 8.3 11.16 3215/10/2012 October 2012 WQ24M W 250 Midwater 2 2 12 0.1 <0.005 <0.002 <0.005 0.1 0.01 22 11.0 <2 18 5.79 8.33 12.1 3215/10/2012 October 2012 WQ25S E 500 Surface 2 <1 <1 0.09 <0.005 <0.002 <0.005 0.09 0.006 25.5 12.5 2.5 <2 18 5.79 8.31 11.43 3215/10/2012 October 2012 WQ25M E 500 Midwater <0.5 <1 <1 0.07 <0.005 <0.002 <0.005 0.07 0.007 25.5 12.5 <2 18.1 5.79 8.3 11.95 3215/10/2012 October 2012 WQ26S E 500 Surface <0.5 5 <1 0.11 0.032 <0.002 0.032 0.14 0.005 25.5 12.5 2.5 <2 18.4 5.80 8.3 11.03 32.115/10/2012 October 2012 WQ26M E 500 Midwater <0.5 3 <1 0.16 0.015 <0.002 0.015 0.18 0.012 25.5 12.5 <2 18 5.80 8.33 11.92 32.115/10/2012 October 2012 WQ27S S 500 Surface <0.5 59 18 0.14 0.015 <0.002 0.015 0.16 0.011 23.8 12.0 2.5 <2 18.3 5.80 8.31 11.39 3215/10/2012 October 2012 WQ27M S 500 Midwater <0.5 51 47 0.15 0.008 0.002 0.01 0.16 0.008 23.8 12.0 <2 18 5.80 8.32 11.91 32.115/10/2012 October 2012 WQ28S W 500 Surface <0.5 <1 <1 0.09 <0.005 <0.002 <0.005 0.09 <0.005 18.5 9.2 2.5 <2 18.6 5.79 8.33 11.38 3215/10/2012 October 2012 WQ28M W 500 Midwater <0.5 <1 1 0.11 <0.005 <0.002 <0.005 0.11 <0.005 18.5 9.2 <2 18.1 5.79 8.31 11.85 32.115/10/2012 October 2012 WQ29S REFNE 2000 Surface <0.5 1 <1 0.11 <0.005 0.003 <0.005 0.11 0.008 17.9 9.0 2.5 <2 18.4 5.82 8.33 11.17 32.115/10/2012 October 2012 WQ29M REFNE 2000 Midwater <0.5 <1 <1 0.08 0.011 0.004 0.015 0.1 0.012 17.9 9.0 <2 18.1 5.79 8.32 12.13 32.115/10/2012 October 2012 WQ30S REFNE 2000 Surface <0.5 1 9 0.1 <0.005 <0.002 <0.005 0.1 <0.005 24.5 12.2 2.5 <2 18.5 5.79 8.33 11.27 32.115/10/2012 October 2012 WQ30M REFNE 2000 Midwater <0.5 <1 <1 0.09 <0.005 <0.002 <0.005 0.09 0.007 24.5 12.2 <2 18.1 5.80 8.31 11.99 32.115/10/2012 October 2012 WQ31S REFSW 2000 Surface <0.5 7 1 0.08 <0.005 0.002 <0.005 0.08 0.006 24 12.0 2.5 <2 18.5 5.80 8.31 11.61 3215/10/2012 October 2012 WQ31M REFSW 2000 Midwater <0.5 11 56 0.12 <0.005 0.003 <0.005 0.12 0.006 24 12.0 <2 18.1 5.79 8.33 12.23 3215/10/2012 October 2012 WQ32S REFSW 2000 Surface <0.5 1 <1 0.11 <0.005 <0.002 <0.005 0.11 0.009 20.7 10.4 2.5 <2 18.6 5.80 8.32 12.24 3215/10/2012 October 2012 WQ32M REFSW 2000 Midwater <0.5 4 28 0.1 <0.005 <0.002 <0.005 0.1 0.008 20.7 10.4 <2 18.1 5.79 8.3 12.53 32
NB1: Where data are preceded by a less than sign (<), the concentration was below the limit of reporting for that analysis.
NB3: Data in italics were not included in statistical analyses due to suspected equipment malfunction.
February 2012
Sample date: Sampling period Sample ID DirectionDistance from
diffuser (m)Depth
Chlorophyll a (mg/m3)
Enterococci (CFU/100ml)
Faecal Coliforms
(CFU/100ml)
Organic Nitrogen as N (mg/L)
Ammonia as N (mg/L)
Nitrite + Nitrate as N (mg/L)
Inorganic Nitrogen as N (mg/L)
Total Nitrogen as N (mg/L)
Total Phosphorus as P (mg/L)
Depth at site (m)
Depth at mid water (m)
Sechi Disc Depth (m)
Turbidity (NTU)
Temperature (oC)
Conductivity (mS/cm)
pHDissolved oxygen (mg/L)
Salinity (‰)
5/02/2013 February 2013 WQ1S DIF 0 Surface 1.1 34 660 0.22 0.044 0.007 0.051 0.27 0.008 21.2 10.6 2 4.3 22.5 5.63 8.2 9.62 39.25/02/2013 February 2013 WQ1M DIF 0 Midwater 1.4 59 1200 0.38 0.121 0.013 0.134 0.51 0.018 21.2 10.6 3.1 22.5 5.67 8.19 9.54 39.55/02/2013 February 2013 WQ2S DIF 0 Surface <1.0 18 210 0.16 0.014 0.005 0.019 0.18 <0.005 21.4 10.7 2.5 4.3 22.5 5.64 8.16 9.53 39.35/02/2013 February 2013 WQ2M DIF 0 Midwater <0.5 23 300 0.16 0.087 0.011 0.098 0.26 <0.005 21.4 10.7 2.9 22.6 5.67 8.16 9.38 39.45/02/2013 February 2013 WQ3S DIF 0 Surface 1.2 51 1100 0.21 0.024 0.007 0.031 0.24 <0.005 20 10.0 3 5.8 22.5 5.62 8.19 9.69 39.25/02/2013 February 2013 WQ3M DIF 0 Midwater 1.3 40 750 0.14 0.068 0.008 0.076 0.22 <0.005 20 10.0 3.1 22.5 5.67 8.18 9.47 39.55/02/2013 February 2013 WQ4S DIF 0 Surface 0.8 69 610 0.11 0.008 0.004 0.012 0.12 <0.005 21 10.5 2.5 2.5 22.9 5.66 8.18 9.51 39.45/02/2013 February 2013 WQ4M DIF 0 Midwater 0.6 1 <1 0.14 <0.005 0.005 0.005 0.14 <0.005 21 10.5 3.3 22.6 5.65 8.16 9.68 39.45/02/2013 February 2013 WQ5S N 30 Surface 0.5 8 9 0.2 <0.005 0.005 0.005 0.2 <0.005 21 10.5 2.5 3.1 22.5 5.65 8.18 9.56 39.45/02/2013 February 2013 WQ5M N 30 Midwater 0.9 36 770 0.19 0.065 0.007 0.072 0.26 0.008 21 10.5 2.6 22.5 5.67 8.17 9.47 39.56/02/2013 February 2013 WQ6S E 30 Surface 0.6 2 28 0.19 0.009 <0.002 0.009 0.2 <0.005 20 10.0 2.5 2.5 22.9 5.67 8.34 9.52 39.56/02/2013 February 2013 WQ6M E 30 Midwater 0.5 1 40 0.15 0.025 0.003 0.028 0.18 <0.005 20 10.0 2.4 22.6 5.68 8.21 9.67 39.65/02/2013 February 2013 WQ7S S 30 Surface 0.5 <1 2 0.2 <0.005 0.005 0.005 0.2 <0.005 22.8 11.4 2.5 3.5 22.6 5.64 8.17 9.64 39.35/02/2013 February 2013 WQ7M S 30 Midwater 1.7 2 2 0.16 <0.005 0.005 0.005 0.16 <0.005 22.8 11.4 2.5 22.5 5.67 8.14 9.55 39.56/02/2013 February 2013 WQ8S W 30 Surface 0.9 1 45 0.16 0.016 <0.002 0.016 0.18 <0.005 20.2 10.1 2.5 4.9 22.8 5.61 8.23 9.5 39.36/02/2013 February 2013 WQ8M W 30 Midwater 1.3 4 300 0.15 0.041 0.003 0.044 0.19 <0.005 20.2 10.1 2.8 22.9 5.67 8.2 9.38 39.65/02/2013 February 2013 WQ9S N 100 Surface 1.1 5 10 0.13 <0.005 0.006 0.006 0.14 <0.005 22.3 11.1 1.5 3.7 22.6 5.63 8.23 9.5 39.25/02/2013 February 2013 WQ9M N 100 Midwater 1.9 46 680 0.2 0.034 0.006 0.04 0.24 0.006 22.3 11.1 3 22.5 5.67 8.16 9.36 39.56/02/2013 February 2013 WQ10S E 100 Surface 0.7 1 1 0.16 <0.005 <0.002 <0.005 0.16 <0.005 23 11.5 2 1.9 23.1 5.65 8.24 9.65 39.46/02/2013 February 2013 WQ10M E 100 Midwater 0.9 <1 1 0.19 0.006 0.003 0.009 0.2 <0.005 23 11.5 2.2 22.6 5.68 8.22 9.59 39.65/02/2013 February 2013 WQ11S E 100 Surface 1.2 1 3 0.2 <0.005 0.004 <0.005 0.2 <0.005 23.6 11.8 1.5 3 22.6 5.66 8.19 9.55 39.45/02/2013 February 2013 WQ11M E 100 Midwater 1.3 <1 <1 0.16 <0.005 0.005 0.005 0.17 <0.005 23.6 11.8 2.6 22.5 5.67 8.17 9.53 39.56/02/2013 February 2013 WQ12S E 100 Surface 0.7 1 <1 0.16 <0.005 <0.002 <0.005 0.16 <0.005 23.6 11.8 2 3.1 23.1 5.65 8.23 9.56 39.56/02/2013 February 2013 WQ12M E 100 Midwater 0.6 <1 1 0.24 <0.005 <0.002 <0.005 0.24 <0.005 23.6 11.8 2.4 22.8 5.67 8.22 9.58 39.55/02/2013 February 2013 WQ13S S 100 Surface 1.6 4 <1 0.15 <0.005 0.006 0.006 0.16 <0.005 23.1 11.5 2 3 22.6 5.65 8.18 9.5 39.45/02/2013 February 2013 WQ13M S 100 Midwater <0.5 1 <1 0.18 <0.005 0.007 0.007 0.19 <0.005 23.1 11.5 2.5 22.5 5.67 8.16 9.58 39.56/02/2013 February 2013 WQ14S S 100 Surface 0.6 95 280 0.16 0.023 0.003 0.026 0.19 0.006 21.4 10.7 2.5 4.8 22.9 5.65 8.22 9.41 39.46/02/2013 February 2013 WQ14M S 100 Midwater 0.6 10 230 0.24 0.039 0.004 0.043 0.28 0.006 21.4 10.7 3.1 22.6 5.67 8.19 9.4 39.65/02/2013 February 2013 WQ15S W 100 Surface <0.5 4 12 0.16 0.01 0.006 0.016 0.18 <0.005 20.4 10.2 2 3 22.6 5.66 8.18 9.41 39.45/02/2013 February 2013 WQ15M W 100 Midwater 0.8 2 <1 0.2 <0.005 0.006 0.006 0.21 <0.005 20.4 10.2 2.8 22.5 5.67 8.16 9.55 39.56/02/2013 February 2013 WQ16S W 100 Surface 0.8 8 13 0.17 <0.005 0.002 <0.005 0.17 <0.005 21.9 10.8 2 3.5 22.9 5.65 8.21 9.55 39.46/02/2013 February 2013 WQ16M W 100 Midwater 1.1 2 39 0.19 0.028 0.003 0.031 0.22 <0.005 21.9 10.8 2.8 22.7 5.66 8.19 9.51 39.55/02/2013 February 2013 WQ17S N 250 Surface 1.4 4 <1 0.2 <0.005 0.005 0.005 0.2 <0.005 21.4 10.7 2 3.5 22.6 5.65 8.17 9.58 39.35/02/2013 February 2013 WQ17M N 250 Midwater 1 49 450 0.12 0.029 0.006 0.035 0.16 <0.005 21.4 10.7 2.7 22.5 5.66 8.16 9.45 39.56/02/2013 February 2013 WQ18S E 250 Surface 0.5 1 <1 0.16 <0.005 <0.002 <0.005 0.16 <0.005 23.9 12.0 2 3.1 23.1 5.66 8.21 9.43 39.56/02/2013 February 2013 WQ18M E 250 Midwater 0.9 1 <1 0.18 0.006 <0.002 0.006 0.19 <0.005 23.9 12.0 2.1 22.7 5.68 8.2 9.56 39.65/02/2013 February 2013 WQ19S E 250 Surface 1.6 <1 3 0.22 <0.005 0.005 0.005 0.22 <0.005 24.8 12.4 2.5 4.5 22.7 5.66 8.17 9.41 39.45/02/2013 February 2013 WQ19M E 250 Midwater 0.9 2 <1 0.29 <0.005 0.006 0.006 0.3 <0.005 24.8 12.4 3.3 22.5 5.67 8.16 9.59 39.56/02/2013 February 2013 WQ20S E 250 Surface 0.6 2 1 0.2 <0.005 <0.002 <0.005 0.2 <0.005 23.6 11.8 2.5 2.7 23.1 5.67 8.2 9.72 39.66/02/2013 February 2013 WQ20M E 250 Midwater 0.9 7 <1 0.2 0.017 0.003 0.02 0.22 <0.005 23.6 11.8 2 22.7 5.67 8.17 9.7 39.65/02/2013 February 2013 WQ21S S 250 Surface 1.2 4 60 0.2 <0.005 0.004 <0.005 0.2 <0.005 22.4 11.2 2.5 3.3 22.6 5.65 8.18 9.56 39.35/02/2013 February 2013 WQ21M S 250 Midwater 0.9 48 450 0.2 0.052 0.008 0.06 0.26 0.01 22.4 11.2 2.8 22.5 5.67 8.16 9.4 39.56/02/2013 February 2013 WQ22S S 250 Surface 0.6 29 150 0.25 0.012 <0.002 0.012 0.26 0.005 21.6 10.8 2 8.2 23 5.65 8.21 9.78 39.46/02/2013 February 2013 WQ22M S 250 Midwater 0.5 8 48 0.2 0.038 0.003 0.041 0.24 0.005 21.6 10.8 3.1 22.6 5.67 8.18 9.65 39.65/02/2013 February 2013 WQ23S W 250 Surface 1.5 <1 <1 0.14 <0.005 0.005 0.005 0.15 <0.005 19.1 9.5 2 3.8 22.7 5.65 8.18 9.42 39.35/02/2013 February 2013 WQ23M W 250 Midwater <0.5 <1 <1 0.22 <0.005 0.004 <0.005 0.22 0.007 19.1 9.5 2.7 22.5 5.66 8.16 9.55 39.46/02/2013 February 2013 WQ24S W 250 Surface 0.5 2 <1 0.22 <0.005 <0.002 <0.005 0.22 <0.005 21.1 10.5 2 3.3 23.3 5.66 8.21 9.56 39.66/02/2013 February 2013 WQ24M W 250 Midwater 0.7 4 <1 0.2 <0.005 <0.002 <0.005 0.2 <0.005 21.1 10.5 3.1 22.6 5.67 8.18 9.79 39.55/02/2013 February 2013 WQ25S E 500 Surface 2.3 <1 <1 0.14 <0.005 0.004 <0.005 0.14 <0.005 24.4 12.2 2 2.7 22.8 5.66 8.18 9.65 39.45/02/2013 February 2013 WQ25M E 500 Midwater 1.1 2 <1 0.11 <0.005 0.007 0.007 0.12 <0.005 24.4 12.2 2.3 22.5 5.68 8.17 9.65 39.66/02/2013 February 2013 WQ26S E 500 Surface 1.1 3 <1 0.18 <0.005 <0.002 <0.005 0.18 <0.005 25 12.5 2.5 6.2 23.1 5.67 8.21 9.69 39.66/02/2013 February 2013 WQ26M E 500 Midwater 0.9 5 <1 0.18 <0.005 <0.002 <0.005 0.18 <0.005 25 12.5 3.2 22.8 5.67 8.21 9.89 39.55/02/2013 February 2013 WQ27S S 500 Surface 1.4 <1 <1 0.19 <0.005 0.004 <0.005 0.19 <0.005 22.4 11.2 2.5 6.2 22.8 5.65 8.17 9.68 39.45/02/2013 February 2013 WQ27M S 500 Midwater 0.6 4 <1 0.13 0.008 0.005 0.013 0.14 <0.005 22.4 11.2 3.2 22.5 5.67 8.17 9.6 39.56/02/2013 February 2013 WQ28S W 500 Surface 0.8 4 <1 0.23 <0.005 0.003 <0.005 0.23 <0.005 17.5 7.8 2 3.3 23.4 5.66 8.23 9.56 39.66/02/2013 February 2013 WQ28M W 500 Midwater 0.8 2 <1 0.19 <0.005 <0.002 <0.005 0.19 <0.005 17.5 7.8 3 22.9 5.67 8.24 9.77 39.66/02/2013 February 2013 WQ29S REFNE 2000 Surface <0.5 3 <1 0.18 <0.005 0.003 <0.005 0.18 <0.005 18.4 9.2 2 4.7 23.4 5.67 8.21 9.95 39.56/02/2013 February 2013 WQ29M REFNE 2000 Midwater <0.5 15 <1 0.15 0.02 <0.002 0.02 0.17 <0.005 18.4 9.2 2.7 22.6 5.68 8.21 9.66 39.66/02/2013 February 2013 WQ30S REFNE 2000 Surface <0.5 3 <1 0.18 <0.005 <0.002 <0.005 0.18 <0.005 24.6 12.3 2 3.1 23.1 5.67 8.24 9.66 39.56/02/2013 February 2013 WQ30M REFNE 2000 Midwater <0.5 7 <1 0.18 <0.005 <0.002 <0.005 0.18 <0.005 24.6 12.3 2.2 22.8 5.68 8.24 9.69 39.65/02/2013 February 2013 WQ31S REFSW 2000 Surface 0.8 <1 <1 0.14 <0.005 0.003 <0.005 0.14 <0.005 22.6 11.3 2 4.7 22.7 5.65 8.17 9.42 39.45/02/2013 February 2013 WQ31M REFSW 2000 Midwater 0.8 <1 <1 0.16 <0.005 0.006 0.006 0.17 <0.005 22.6 11.3 2.7 22.5 5.67 8.17 9.73 39.66/02/2013 February 2013 WQ32S REFSW 2000 Surface 0.5 2 10 0.4 0.011 0.003 0.014 0.41 <0.005 20 10.0 2 3.7 23.1 5.68 8.28 10.18 39.66/02/2013 February 2013 WQ32M REFSW 2000 Midwater 0.7 2 <1 0.39 0.012 <0.002 0.012 0.4 <0.005 20 10.0 3.7 22.6 5.67 8.24 9.77 39.5
NB1: Where data are preceded by a less than sign (<), the concentration was below the limit of reporting for that analysis.
April 2013
Sample date: Sampling period Sample ID DirectionDistance from
diffuser (m)Depth
Chlorophyll a (mg/m3)
Enterococci (CFU/100ml)
Faecal Coliforms
(CFU/100ml)
Organic Nitrogen as N (mg/L)
Ammonia as N (mg/L)
Nitrite + Nitrate as N (mg/L)
Inorganic Nitrogen as N (mg/L)
Total Nitrogen as N (mg/L)
Total Phosphorus as P (mg/L)
Depth at site (m)
Depth at mid water (m)
Sechi Disc Depth (m)
Turbidity (NTU)
Temperature (oC)
Conductivity (mS/cm)
pHDissolved oxygen (mg/L)
Salinity (‰)
2/04/2013 April 2013 WQ1S DIF 0 Surface 0.7 96 1200 0.23 0.083 0.003 0.086 0.32 0.007 21.8 10.9 2 0.8 22.7 4.80 8.62 7.08 40.12/04/2013 April 2013 WQ1M DIF 0 Midwater 0.7 12 190 0.46 0.025 <0.002 0.025 0.48 0.006 21.8 10.9 0.5 22.9 4.87 9.11 6.69 40.92/04/2013 April 2013 WQ2S DIF 0 Surface 0.8 60 400 0.15 0.071 <0.002 0.071 0.22 0.005 22 11.0 2 0.2 22.8 4.88 9.44 7.13 40.82/04/2013 April 2013 WQ2M DIF 0 Midwater <0.5 32 220 0.16 0.012 <0.002 0.012 0.17 <0.005 22 11.0 0 22.9 4.89 9.25 6.45 412/04/2013 April 2013 WQ3S DIF 0 Surface 0.9 100 1400 0.18 0.125 <0.002 0.125 0.31 0.009 21 10.5 2 1.2 22.8 4.82 9.2 7.73 40.32/04/2013 April 2013 WQ3M DIF 0 Midwater <0.5 380 1200 0.23 0.033 <0.002 0.033 0.26 0.01 21 10.5 1.6 22.8 4.89 9.15 8.52 41.12/04/2013 April 2013 WQ4S DIF 0 Surface 0.7 370 5500 0.21 0.068 <0.002 0.068 0.28 0.04 22.4 11.2 1 2.6 22.9 4.88 9.37 6.85 412/04/2013 April 2013 WQ4M DIF 0 Midwater 0.7 120 250 0.13 0.012 <0.002 0.012 0.14 <0.005 22.4 11.2 0 22.9 4.90 9.26 6.43 41.12/04/2013 April 2013 WQ5S N 30 Surface 0.6 110 510 0.19 0.06 0.003 0.063 0.25 <0.005 21.2 10.6 2 1.1 22 4.86 9.2 7.48 40.62/04/2013 April 2013 WQ5M N 30 Midwater 0.7 10 61 0.16 0.012 <0.002 0.012 0.17 <0.005 21.2 10.6 0.4 22.9 4.89 9.15 6.83 412/04/2013 April 2013 WQ6S E 30 Surface 0.7 140 450 0.14 0.086 0.005 0.091 0.23 0.006 21.4 10.7 2 0.5 22.8 4.88 9.28 6.91 40.92/04/2013 April 2013 WQ6M E 30 Midwater 0.6 95 390 0.18 0.025 <0.002 0.025 0.2 <0.005 21.4 10.7 0.3 22.8 4.90 9.26 6.65 41.12/04/2013 April 2013 WQ7S S 30 Surface 0.9 120 360 0.21 0.046 <0.002 0.046 0.26 0.032 22.8 11.4 2 0.6 22.4 4.88 9.2 7.62 40.92/04/2013 April 2013 WQ7M S 30 Midwater 0.6 150 400 0.17 0.022 <0.002 0.022 0.19 0.007 22.8 11.4 0.6 22.8 4.89 9.15 7.02 41.12/04/2013 April 2013 WQ8S W 30 Surface 0.7 130 450 0.13 0.065 0.003 0.068 0.2 0.006 21 10.5 2 4.4 22.8 4.89 9.21 6.79 412/04/2013 April 2013 WQ8M W 30 Midwater 0.5 130 350 0.14 <0.005 <0.002 <0.005 0.14 <0.005 21 10.5 0.1 22.8 4.90 9.27 6.63 41.12/04/2013 April 2013 WQ9S N 100 Surface 0.7 40 280 0.15 0.031 <0.002 0.031 0.18 <0.005 23.1 11.6 2.5 1.6 22.8 4.89 9.28 7.29 41.12/04/2013 April 2013 WQ9M N 100 Midwater 0.9 20 91 0.16 0.009 <0.002 0.009 0.17 <0.005 23.1 11.6 0.4 22.8 4.89 9.17 7.08 41.12/04/2013 April 2013 WQ10S E 100 Surface 0.5 60 340 0.14 0.076 0.003 0.079 0.22 <0.005 23.6 11.8 2 0.6 22.8 4.88 9.28 6.43 412/04/2013 April 2013 WQ10M E 100 Midwater <0.5 40 190 0.13 0.018 0.004 0.022 0.15 <0.005 23.6 11.8 0.5 22.8 4.90 9.26 6.63 41.22/04/2013 April 2013 WQ11S E 100 Surface 0.9 200 2000 0.16 0.072 0.012 0.084 0.24 0.015 23.6 11.8 1.5 2.4 22.8 4.88 9.22 6.92 40.92/04/2013 April 2013 WQ11M E 100 Midwater 0.6 150 330 0.16 0.011 <0.002 0.011 0.17 <0.005 23.6 11.8 0.9 22.8 4.89 9.17 6.61 412/04/2013 April 2013 WQ12S E 100 Surface 0.6 180 390 0.14 0.061 <0.002 0.061 0.2 0.018 23.8 11.9 1.5 2.1 23 4.89 9.36 6.4 41.12/04/2013 April 2013 WQ12M E 100 Midwater 0.5 46 84 0.13 0.008 <0.002 0.008 0.14 <0.005 23.8 11.9 0.1 22.9 4.90 9.27 6.57 41.22/04/2013 April 2013 WQ13S S 100 Surface 0.9 1000 1500 0.17 0.071 <0.002 0.071 0.24 0.018 23 11.5 1.5 1.8 22.8 4.88 9.29 6.5 40.92/04/2013 April 2013 WQ13M S 100 Midwater 0.6 50 150 0.16 0.014 <0.002 0.014 0.17 <0.005 23 11.5 0.1 22.8 4.89 9.18 6.6 412/04/2013 April 2013 WQ14S S 100 Surface 0.9 120 360 0.14 0.087 0.002 0.089 0.23 0.009 22 11.0 2 4.6 22.9 4.89 9.37 7.66 41.12/04/2013 April 2013 WQ14M S 100 Midwater 0.5 60 140 0.13 0.01 <0.002 0.01 0.14 <0.005 22 11.0 0.3 22.8 4.89 9.29 6.91 41.12/04/2013 April 2013 WQ15S W 100 Surface 0.5 120 410 0.14 0.093 0.002 0.095 0.24 <0.005 20.5 10.3 3 5.7 22.8 4.87 9.24 6.63 40.92/04/2013 April 2013 WQ15M W 100 Midwater 0.8 52 150 0.17 <0.005 0.002 <0.005 0.17 <0.005 20.5 10.3 0.7 22.8 4.89 9.19 6.46 412/04/2013 April 2013 WQ16S W 100 Surface 0.6 60 230 0.12 0.088 0.039 0.127 0.25 <0.005 21.2 10.6 2 0.6 22.8 4.88 9.38 6.68 40.92/04/2013 April 2013 WQ16M W 100 Midwater <0.5 40 110 0.12 0.01 0.004 0.014 0.13 <0.005 21.2 10.6 0.1 22.8 4.88 9.28 6.58 412/04/2013 April 2013 WQ17S N 250 Surface <0.5 16 43 0.14 0.037 <0.002 0.037 0.18 <0.005 21.8 10.9 2.5 0.6 22.9 4.89 9.29 6.9 41.12/04/2013 April 2013 WQ17M N 250 Midwater <0.5 20 77 0.19 0.017 <0.002 0.017 0.21 <0.005 21.8 10.9 0.4 22.7 4.89 9.2 6.61 412/04/2013 April 2013 WQ18S E 250 Surface <0.5 46 110 0.14 0.077 0.005 0.082 0.22 <0.005 24.4 12.2 1.5 0.3 22.9 4.88 9.28 7.46 40.92/04/2013 April 2013 WQ18M E 250 Midwater <0.5 10 54 0.12 0.016 <0.002 0.016 0.14 <0.005 24.4 12.2 0.3 22.8 4.89 9.26 6.55 41.12/04/2013 April 2013 WQ19S E 250 Surface <0.5 160 270 0.16 0.064 <0.002 0.064 0.22 0.01 24.4 12.2 2.5 1.4 22.9 4.89 9.3 6.76 412/04/2013 April 2013 WQ19M E 250 Midwater 0.6 180 360 0.5 0.016 <0.002 0.016 0.52 <0.005 24.4 12.2 0.4 22.9 4.89 9.21 6.68 41.12/04/2013 April 2013 WQ20S E 250 Surface 0.8 <1 2 0.11 0.008 <0.002 0.008 0.12 <0.005 25 12.5 2 2.3 22.8 4.88 9.41 6.27 412/04/2013 April 2013 WQ20M E 250 Midwater 0.6 4 5 0.14 0.012 0.003 0.015 0.15 <0.005 25 12.5 1 22.9 4.90 9.29 6.74 41.22/04/2013 April 2013 WQ21S S 250 Surface <0.5 34 160 0.11 0.047 0.013 0.06 0.17 <0.005 22.8 11.4 2.5 0.1 22.9 4.88 9.28 6.64 412/04/2013 April 2013 WQ21M S 250 Midwater <0.5 25 59 0.12 0.022 0.004 0.026 0.15 <0.005 22.8 11.4 0.1 22.8 4.89 9.22 6.63 41.12/04/2013 April 2013 WQ22S S 250 Surface <0.5 3 1 0.22 0.008 0.003 0.011 0.23 <0.005 23 11.5 2 0.5 23 4.90 9.43 6.71 412/04/2013 April 2013 WQ22M S 250 Midwater 0.7 <1 5 0.16 0.014 <0.002 0.014 0.17 <0.005 23 11.5 0.2 22.8 4.89 9.29 6.61 41.12/04/2013 April 2013 WQ23S W 250 Surface <0.5 36 110 0.2 0.016 0.002 0.018 0.22 <0.005 19.1 9.6 2 0.3 22.4 4.88 9.36 6.86 40.82/04/2013 April 2013 WQ23M W 250 Midwater 0.6 110 240 0.16 0.092 0.003 0.095 0.25 0.005 19.1 9.6 0 22.8 4.88 9.24 6.56 412/04/2013 April 2013 WQ24S W 250 Surface <0.5 21 44 0.12 0.061 0.005 0.066 0.19 <0.005 24 12.0 2 1 22.9 4.89 9.43 5.91 412/04/2013 April 2013 WQ24M W 250 Midwater <0.5 5 3 0.14 0.016 0.002 0.018 0.16 <0.005 24 12.0 0.1 22.7 4.89 9.31 6.02 412/04/2013 April 2013 WQ25S E 500 Surface 0.7 32 7 0.13 0.059 <0.002 0.059 0.19 <0.005 25.3 12.7 2 4.1 23 4.88 9.43 5.8 412/04/2013 April 2013 WQ25M E 500 Midwater 1.3 16 24 0.13 0.009 <0.002 0.009 0.14 <0.005 25.3 12.7 0.2 22.9 4.89 9.29 5.87 41.12/04/2013 April 2013 WQ26S E 500 Surface 1.8 <1 <1 0.12 0.01 0.002 0.012 0.13 <0.005 26.4 13.2 1.5 3.2 22.9 4.88 9.44 6.44 412/04/2013 April 2013 WQ26M E 500 Midwater <0.5 <1 <1 0.14 <0.005 0.002 <0.005 0.14 <0.005 26.4 13.2 0.5 22.8 4.88 9.3 6.1 412/04/2013 April 2013 WQ27S S 500 Surface <0.5 7 <1 0.14 0.012 <0.002 0.012 0.15 <0.005 23.8 11.9 2 0.5 22.8 4.89 9.21 7 412/04/2013 April 2013 WQ27M S 500 Midwater 0.7 12 35 0.14 0.02 0.003 0.023 0.16 <0.005 23.8 11.9 0 22.8 4.89 9.24 7.03 412/04/2013 April 2013 WQ28S W 500 Surface <0.5 12 9 0.16 0.048 0.002 0.05 0.21 <0.005 19.1 9.6 2.5 1.1 22.9 4.80 9.31 6.43 412/04/2013 April 2013 WQ28M W 500 Midwater 0.5 10 13 0.12 0.015 <0.002 0.015 0.14 <0.005 19.1 9.6 0 22.7 4.89 9.26 6.51 41.12/04/2013 April 2013 WQ29S REFNE 2000 Surface 0.7 2 <1 0.2 <0.005 <0.002 <0.005 0.2 <0.005 18.4 9.2 1.5 0.4 23.1 4.89 9.4 6.52 41.12/04/2013 April 2013 WQ29M REFNE 2000 Midwater <0.5 <1 <1 0.17 <0.005 <0.002 <0.005 0.17 <0.005 18.4 9.2 0.2 22.9 4.89 9.27 5.92 41.12/04/2013 April 2013 WQ30S REFNE 2000 Surface <0.5 <1 <1 0.14 <0.005 <0.002 <0.005 0.14 0.005 25.5 12.8 2 0.1 23.2 4.90 9.37 6.35 41.12/04/2013 April 2013 WQ30M REFNE 2000 Midwater <0.5 <1 <1 0.12 0.006 <0.002 0.006 0.13 <0.005 25.5 12.8 0 23 4.90 9.28 5.89 41.22/04/2013 April 2013 WQ31S REFSW 2000 Surface <0.5 <1 <1 0.17 <0.005 0.01 0.01 0.18 <0.005 23.6 11.8 2 0.1 23 4.90 9.36 6.63 41.12/04/2013 April 2013 WQ31M REFSW 2000 Midwater <0.5 <1 <1 0.14 0.01 <0.002 0.01 0.15 <0.005 23.6 11.8 0.1 22.7 4.89 9.26 6.86 412/04/2013 April 2013 WQ32S REFSW 2000 Surface <0.5 <1 <1 0.13 0.006 0.002 0.008 0.14 <0.005 20.3 10.2 2.5 0.4 22.8 4.88 9.34 6.87 40.92/04/2013 April 2013 WQ32M REFSW 2000 Midwater <0.5 1 9 0.13 0.027 0.003 0.03 0.16 <0.005 20.3 10.2 0.2 22.6 4.88 9.27 6.67 40.9
NB1: Where data are preceded by a less than sign (<), the concentration was below the limit of reporting for that analysis.
NB2: Data in italics were not included in statistical analyses due to suspected equipment malfunction.
HUNTER WATER
WATER QUALITY STUDY
BURWOOD BEACH WWTW
Page 102 301020-03413 : 210 FINAL DRAFT : October 2013
Appendix 3 – CEE Analysis of Water Quality Data by
Zone
30 August 2013 Bruce Cole Science Officer Wastewater Planning Hunter Water Corporation 36 Honeysuckle Drive, Newcastle NSW 2300 Dear Bruce, Hunter Water Corporation is conducting a three year environmental assessment of their ocean outfall discharges at Burwood Beach and Boulder Bay. A water quality study is a component of the assessment and is being conducted by Worley Parsons. The collected water quality data was sent to CEE for an independent review of the effects of the outfall discharge on water quality in Burwood Beach. Our interpretation of the water quality data from Burwood Beach is presented in this report. Water Quality Monitoring The water quality monitoring was undertaken to characterise the changes to water quality in Burwood Beach as a result of the effluent discharge and to define the footprint of the changes. Water samples were collected from a boat at a range of distances from the outfall and analysed to determine the concentrations of nutrients (ammonia, oxidised nitrogen, total nitrogen and total phosphorus), microbiological indicators (enterococci and faecal coliforms) and phytoplankton (chlorophyll-a) in a NATA-accredited laboratory. Physicochemical parameters (salinity, temperature, dissolved oxygen and pH) were measured in-situ at the same time as the water samples were collected. Water samples were collected at thirty sites, which were arranged in a radial pattern (at distances of 0 m, 30 m, 100 m, 250 m and 500 m) around the outfall diffuser, with reference sites at a distance of approximately 2 km from the outfall (as shown in Figures 1 and 2). The location of sampling sites took into account the site of the diffuser, prevailing hydrodynamic conditions in the area and plume characteristics. Eight sets of water samples were undertaken over a two year period with samples being collected on each occasion from sites on the surface and at mid-depth. A total of 60 water samples were collected during each sampling round. Table 1 shows the parameters tested, with the level of reporting (LOR) and the water quality guideline levels for each parameter.
CEE PTY LTD ACN 245 986
Environmental Scientists and Engineers
Level 1, 90 Bridge Road, PO Box 201, Richmond VIC 3121
TEL 03 9429 4644 FAX 03 9428 0021 EMAIL [email protected]
Burwood Beach Water Quality Assessment 2
Figure 1 - Location of Burwood Beach Outfall and Monitoring Sites
Burwood Beach Water Quality Assessment 3
Figure 2 - Location of Burwood Beach Outfall and Monitoring Sites
Burwood Beach Water Quality Assessment 4
Table 1 - Water Quality Parameters
Burwood Beach Waste Water Treatment Works (WWTW) The source of the effluent discharged through the Burwood Beach outfall is the Burwood Beach Wastewater Treatment Works (WWTW). The Burwood Beach WWTW treats wastewater from Newcastle and the surrounding suburbs, serving approximately 185,000 people with an average dry weather flow of 48 million litres of wastewater per day (48 ML/d). Over the next 30 years these flows are expected to increase to 55 - 60 ML/d, even with water conservation measures in place. The secondary treatment process at Burwood Beach WWTW consists of fine screening to remove large and coarse particulates, followed by biological secondary treatment using an innovative cascading filter and activated sludge process including settling. The secondary effluent from Burwood Beach WWTW is discharged to the ocean through a multi-port diffuser which extends 1,500 m offshore, with eight multi-port diffusers at a depth of approximately 22 m. Approximately 2 ML/d of activated sludge, which is surplus to treatment requirements, is discharged to the ocean via a separate multi-port diffuser that extends slightly further offshore than the effluent outfall. Both outfalls have been operating in their current configuration since January 1994.
Burwood Beach Water Quality Assessment 5
Effluent Quality The median effluent quality from the Burwood Beach WWTW, based on extensive monitoring by HWC between 2006 and 2013, is summarized in the table below.
Table A – Effluent Characteristics and Signature of Effluent After Dilution
Water Quality Parameter
Units Median Level in Effluent
90 % Level in Effluent
Median Level in Sludge
After Effluent Dilution
After Sludge Dilution
Ammonia mg/L 23 29 24 0.128 0.120
Oxidised Nitrogen mg/L 1.6 3.7 1.0 0.009 0.005
Total Nitrogen mg/L 28 38 29 0.156 0.145
Total Phosphorus mg/L 2.6 4.8 2.3 0.014 0.012
Suspended Solids
mg/L 27 80 3,200 0.2 16
BOD mg/L 23 60 4,000 0.1 20
Salinity ppt 0.5 0.8 0.5 0.003 0.003
Enterococci cfu/ 100 mL
160,000 400,000 1,250,000 900 6,300
Faecal Coliforms cfu/ 100mL
2,500,000 5,000,000 5,500,000 14,000 28,000
From examination of the analyses summarized in the table, it is apparent that the median concentrations of nutrients (ammonia, oxidized nitrogen, total nitrogen and total phosphorus) are very similar in effluent and sludge. On the other hand, the median suspended solids and BOD concentrations are very different in effluent and sludge, with much higher levels of these constituents in the sludge (reflecting the high organic solids content in the sludge). The concentrations of enterococci and faecal coliforms are high in both effluent and sludge, with particularly elevated levels in the sludge. Initial Dilution Consulting Environmental Engineers (CEE 2007) calculated a typical initial dilution of 219:1 for the Burwood effluent outfall, assuming a discharge rate of 43 ML/d and all duckbill valves in operation. Allowing for the reduction in dilution due to higher flows and the orientation of the diffuser ports parallel to the currents, initial dilution now is expected to be around 180:1. The Water Research Lab (WRL 2007) carried out field tests of effluent dilution using rhodamine dye. The dilution of the surface field showed a typical dilution of 185:1. WRL reported an average near-field dilution of 207:1. It is therefore reasonable to base the environmental risk assessment of the effects of effluent discharge on an effluent plume near the ocean surface with an initial dilution in the range of 180:1.
Burwood Beach Water Quality Assessment 6
CEE also calculated the dilution of the combination of sludge and effluent discharge through the sludge diffuser. The model predicts a typical dilution of 475:1 if the discharged sludge rises to the ocean surface, and about 250:1 if the sludge plume is trapped by stratification at mid-depth (CEE, 2007). As a check, the WRL computer model showed a median dilution of 300:1, with a minimum dilution of 100:1 when strong stratification decreases the rise and dilution of the small sludge plumes, and a maximum dilution at times of strong currents exceeding 1,000:1 (WRL, 2007). The WRL model shows the sludge plume is often trapped well below the surface by the natural stratification of the ocean water column. Based on this range of dilution values, the initial dilution assumed for the sludge discharge in this report is 200:1. Signature of Effluent in Burwood Beach The second last column of Table A shows the expected increase in concentration of the various parameters in ocean waters above the diffuser with effluent discharge at the median concentration at a dilution of 180:1. It is appreciated that the effluent concentrations vary over a range, as illustrated in Table A, and that the dilution also varies over a range, depending on the currents, wave conditions and discharge rate. Nonetheless, the concentrations in the final column dilution of Table A give an indication of the expected signature of the effluent constituents above ambient concentrations in the coastal waters at the Burwood Beach outfalls. The final column of Table A shows the expected increase in concentration of the various parameters in ocean waters above the diffuser with sludge discharge at the median concentration at a dilution of 200:1. It can be seen that the predicted increment in concentrations of nutrients are much the same for the diluted effluent and sludge plumes. For ammonia, as an example, the increment is 128 ug/L for effluent and 120 ug/L for sludge. For total nitrogen, as another example, the increment is 156 ug/L for effluent and 145 ug/L for sludge. Thus it is not possible or necessary to distinguish between the effluent or sludge plumes in terms of effects on nutrient concentrations in the ocean waters near the outfall. The sludge plume may be detected in terms of the changes in solids levels (increase of about 16 mg/L of SS (which should increase turbidity significantly). There is potentially a large increase in enterococci and faecal coliforms particularly in the sludge plume, which has a signature of 6,300 cfu/100 mL for enterococci and 28,000
cfu/100 mL for faecal coliforms. Despite there being such a large difference between the enterococci signature for effluent (900 cfu/100 mL) and sludge (6,300 cfu/100 mL), this does not show up in the monitoring data as a difference in samples collected on the surface (more likely to contain diluted effluent) and mid-water (more likely to contain diluted sludge). The 90 percentile concentrations for enterococci in all water quality samples collected at the outfall and 30 m distance sites was 160 cfu/100 mL for surface samples and 130 cfu/100 mL for mid-water samples. The 90 percentile enterococci level at 100 m from the outfall was 200 cfu/100 mL for surface samples and 130 cfu/100 mL for mid-water samples.
Burwood Beach Water Quality Assessment 7
Interpretation of Water Quality Data The Worley Parsons report provides a series of statistical analyses of the water quality data including distance based linear modelling (DISTLM) and distance based redundancy analysis (dbRDA) using the software program PRIMER 6 with the Permanova+ addition. Response variables for the analysis consisted of a surface and mid-water variable for concentrations of each organic and inorganic parameter measured. Data were then analysed by Worley Parsons using a non-metric multidimensional scaling (MDS) plot to ascertain potentially important variables (sample date, season, year, distance from the outfall, direction from the outfall and depth at sample site). Rainfall in the preceding 7, 5 and 3 days was also examined. In this report, the raw data are directly compared for four zones at different distances from the outfall:
1. Samples at the outfall and 30 m distance (128 samples); 2. Samples at 120 m distance (128 samples); 3. Samples at 250 m distance (124 samples); and 4. Samples from 500 m and 2,000 m distance (126 samples).
The measured concentrations in each zone for each parameter have been sorted and plotted from highest to lowest concentration for the four zones. Strictly speaking, the numbers should be normalized to a common total, but the raw comparison is sufficient to show the differences between the concentration patterns in the various zones. The highest 40 concentrations in each zone are then tabulated to allow direct comparison of values. Colours are used in the tables to distinguish between various concentrations (eg, all values higher than the ANZECC guideline limit are coloured yellow). This allows the reader to make a direct comparison of the number of samples in each zone, including the zone for distant samples (500 m and 2,000 m), which exceed the guideline trigger. Comments are made on the figures and tabulated values in the following sequence:
1. Parameter concentrations as a function of distance from the outfall – ie, whether the highest concentrations occur in Zone 1, with progressively lower concentrations in Zone 2 and Zone 3, and lowest concentrations in Zone 4 (corresponding to a readily detected outfall effect), or whether there are a similar range of concentrations in each zone (corresponding to no clearly observable footprint of the outfall for a water quality parameter);
2. Whether the difference in concentrations in Zone 1 (at the outfall) compared to the concentrations in Zone 4 match the expected increment due to the effluent discharge as listed in Table A;
3. Proportion of samples with low concentrations (eg, at or near the level of reporting) in each Zone, indicating good water quality;
4. Proportion of samples in each Zone with elevated concentrations (eg, above the ANZECC guideline default trigger level); and
5. Estimated spatial footprint of the outfall for each parameter.
Burwood Beach Water Quality Assessment 8
Ammonia Figure 1 shows the sorted ammonia concentrations for each of the four zones. The highest concentration was measured in the outfall zone and for most of the range there is a consistent trend in ammonia concentration with distance, with highest concentrations in the outfall zone, somewhat lower concentrations at 100 m distance, lower concentrations at 250 m distance and lowest concentrations in the 500 m and reference zone. For about 60 sets of samples, there appears to be a tendency for the concentrations at the outfall to be 50 to 60 ug/L higher than for the reference zone. This increase is about half of the signature of ammonia in the diluted effluent and sludge plumes of 120 to 128 ug/L respectively (see table A). Table 1 lists the top 40 ammonia concentrations measured in the four zones. There are many samples above the ammonia trigger level of 20 ug/L, including 16 samples collected in Zone 4. There are many more samples with higher ammonia levels in and near the outfall. The ammonia signature (< 120 ug/L) is large and therefore easily detected in this monitoring program. In summary, there is a clear and consistent footprint of elevated ammonia concentration detected in this water quality study which extends to 500 m from the outfalls.
Figure 1 - Burwood Beach Water Quality – Ammonia
Burwood Beach Water Quality Assessment 9
Table 1 - Top 40 Ammonia Concentrations per Area - Burwood Beach
(mg/L)
0-30 m 100 m 250 m 500-2000 m
0.155 0.134 0.092 0.068
0.153 0.102 0.077 0.068
0.125 0.099 0.077 0.067
0.121 0.099 0.068 0.059
0.111 0.093 0.064 0.048
0.101 0.090 0.063 0.045
0.100 0.088 0.061 0.039
0.090 0.087 0.060 0.035
0.088 0.084 0.06 0.032
0.087 0.080 0.056 0.029
0.086 0.076 0.054 0.027
0.083 0.072 0.053 0.024
0.081 0.071 0.052 0.023
0.079 0.069 0.05 0.021
0.074 0.063 0.048 0.020
0.072 0.062 0.047 0.020
0.072 0.061 0.046 0.020
0.071 0.055 0.045 0.020
0.071 0.052 0.044 0.016
0.069 0.048 0.038 0.015
0.069 0.048 0.038 0.015
0.068 0.047 0.037 0.015
0.068 0.046 0.034 0.015
0.068 0.046 0.033 0.012
0.068 0.044 0.029 0.012
0.068 0.044 0.028 0.011
0.065 0.044 0.028 0.011
0.065 0.04 0.027 0.011
0.065 0.039 0.026 0.010
0.064 0.038 0.025 0.010
0.062 0.034 0.025 0.009
0.06 0.033 0.023 0.009
0.06 0.031 0.022 0.009
0.058 0.028 0.022 0.009
0.056 0.025 0.021 0.009
0.055 0.025 0.017 0.008
0.054 0.025 0.017 0.008
0.054 0.023 0.016 0.008
Burwood Beach Water Quality Assessment 10
Oxidised Nitrogen Figure 2 shows the sorted oxidized nitrogen concentrations for each of the four zones. The highest concentration was measured at the outfall zone and there is a small but consistent pattern of higher oxidised nitrogen concentrations at the outfall zone compared to the other three zones. Concentrations at the 100 m zone are slightly higher than for the other two zones, but there is little difference between the oxidised nitrogen concentrations in the 250 m zone and the 500 m reference zone. The reason for this is that the signature for oxidised nitrogen in the diluted plumes is only 5 to 9 ug/L (see Table A) which is small in relation to the ambient concentrations of oxidised nitrogen. Table 2 lists the top 40 oxidised nitrogen concentrations in the four zones. From the table, there are many events where the oxidised nitrogen at the outfall zone is about 20 ug/L above the reference zone. There are many events in all Zones where the measured oxidised nitrogen concentration exceeded the trigger level of 25 ug/L including many samples from the reference zones. This suggests a locally derived trigger for oxidised nitrogen would be higher than the default value. In summary, oxidized nitrogen appears to be more elevated at the outfall and 100 m zones compared to the reference zone, suggesting a footprint extending about 100 m from the outfall.
Figure 2 - Burwood Beach Water Quality - Oxidised Nitrogen
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
1 5 9
13
17
21
25
29
33
37
41
45
49
53
57
61
65
69
73
77
81
85
89
93
97
10
1
10
5
10
9
11
3
11
7
12
1
12
5
Oxi
dis
ed
Nit
roge
nm
g/L
Sorted sample number
0-30 100 250 500-2000
Burwood Beach Water Quality Assessment 11
Table 2 - Top 40 Oxidised Nitrogen Concentrations per Area - Burwood Beach (mg/L)
0-30 m 100 m 250 m 500-2000 m
0.154 0.116 0.113 0.087
0.149 0.094 0.096 0.087
0.131 0.088 0.087 0.084
0.103 0.088 0.084 0.081
0.100 0.087 0.082 0.080
0.090 0.085 0.079 0.080
0.088 0.085 0.077 0.078
0.086 0.084 0.077 0.078
0.086 0.083 0.076 0.076
0.086 0.083 0.076 0.076
0.085 0.083 0.076 0.075
0.084 0.082 0.076 0.075
0.084 0.077 0.075 0.074
0.084 0.076 0.075 0.072
0.083 0.076 0.074 0.052
0.083 0.075 0.074 0.049
0.081 0.075 0.042 0.044
0.08 0.074 0.040 0.040
0.077 0.044 0.039 0.039
0.077 0.041 0.039 0.039
0.076 0.039 0.038 0.039
0.039 0.038 0.038 0.039
0.039 0.038 0.038 0.038
0.038 0.038 0.038 0.038
0.038 0.037 0.038 0.038
0.038 0.037 0.037 0.037
0.038 0.037 0.037 0.036
0.038 0.037 0.036 0.034
0.037 0.037 0.036 0.034
0.037 0.036 0.036 0.033
0.037 0.036 0.035 0.032
0.037 0.036 0.034 0.031
0.037 0.036 0.013 0.029
0.037 0.036 0.011 0.02
0.037 0.035 0.011 0.02
0.036 0.02 0.008 0.017
0.036 0.018 0.008 0.013
0.013 0.012 0.006 0.011
0.013 0.01 0.006 0.01
0.011 0.01 0.005 0.009
Burwood Beach Water Quality Assessment 12
Total Nitrogen Figure 3 shows the sorted total nitrogen concentrations for each of the four zones. The highest concentrations are in the outfall zone, although a few high concentrations also were recorded in Zone 4. There is a consistent trend in total nitrogen concentration with distance, with highest concentrations in the outfall zone, somewhat lower concentrations at 100 m distance, lower concentrations at 250 m distance and lowest concentrations in the 500 m reference zone. The concentrations in the outfall zone are generally 80 to 150 ug/L higher than in the reference zone. This difference corresponds to the signature of the plumes of 145 to 156 ug/L (see Table A). It is estimated that the elevated total nitrogen level extends out to beyond the 250 m zone. Table 3 lists the top 40 total nitrogen concentrations in the four zones. All of the values listed in the table exceed the ANZECC default trigger level of 120 ug/L. From the table, the total nitrogen at the outfall zone is 60 to 150 ug/L above the other zones. The 90 percentile concentrations for the four zones are 320 ug/L for Zone 1; 240 ug/L for Zone 2, 220 ug/L for Zone 3 and 200 ug/L for Zone 4. This suggests a footprint extending out to more than 250 m from the outfall. In summary, there appears to be a consistent footprint of elevated total nitrogen concentrations detected in this water quality study to more than 250 m from the outfall.
Figure 3 - Burwood Beach Water Quality - Total Nitrogen
Burwood Beach Water Quality Assessment 13
Table 3 - Top 40 Total Nitrogen Concentrations per Area - Burwood Beach
(mg/L)
0-30 m 100 m 250 m 500-2,000 m
0.56 0.28 0.52 0.41
0.54 0.27 0.30 0.40
0.51 0.26 0.26 0.36
0.48 0.26 0.26 0.35
0.47 0.25 0.25 0.33
0.37 0.25 0.24 0.23
0.34 0.24 0.23 0.21
0.34 0.24 0.22 0.20
0.32 0.24 0.22 0.19
0.32 0.24 0.22 0.19
0.31 0.24 0.22 0.19
0.30 0.23 0.22 0.19
0.30 0.22 0.22 0.19
0.28 0.22 0.22 0.18
0.28 0.22 0.21 0.18
0.28 0.21 0.20 0.18
0.27 0.21 0.20 0.18
0.27 0.21 0.20 0.18
0.26 0.21 0.20 0.18
0.26 0.21 0.20 0.18
0.26 0.20 0.19 0.18
0.26 0.20 0.19 0.17
0.25 0.20 0.18 0.17
0.25 0.20 0.18 0.17
0.24 0.20 0.18 0.16
0.24 0.20 0.18 0.16
0.24 0.20 0.18 0.16
0.24 0.20 0.17 0.16
0.23 0.19 0.17 0.16
0.23 0.19 0.17 0.16
0.23 0.19 0.16 0.15
0.23 0.18 0.16 0.15
0.22 0.18 0.16 0.14
0.22 0.18 0.16 0.14
0.22 0.18 0.16 0.14
0.21 0.18 0.15 0.14
0.21 0.17 0.15 0.14
0.21 0.17 0.15 0.14
0.20 0.17 0.15 0.14
0.20 0.17 0.15 0.14
Burwood Beach Water Quality Assessment 14
Total Phosphorus Figure 4 shows the sorted total phosphorus concentrations for each of the four zones. There is a consistent trend in total nitrogen concentration with distance, with highest concentrations in the outfall zone, somewhat lower concentrations at 100 m distance, lower concentrations at 250 m distance and lowest concentrations in the 500 m reference zone. For much of the range, the concentration in the outfall zone was 7 to 18 ug/L above the concentration in the reference zone. This difference corresponds to the signature of total phosphorus in the diluted effluent and sludge plumes of 12 to 14 ug/L (see table A). This suggests a footprint of elevated total phosphorus at the outfall zone extending out to beyond 250 m distance. Table 4 lists the top 40 total phosphorus concentrations in the four zones. In all rows of the table total phosphorus concentrations at the outfall zone is at least 7 ug/L above the concentration in the reference zone, with the concentrations in other zones being between these two values. The 90 percentile concentrations for the four zones are 26 ug/L for Zone 1; 23 ug/L for Zone 2, 18 ug/L for Zone 3 and 16 ug/L for Zone 4. This suggests a footprint extending further than 250 m from the outfall. Note that there are samples in all zones that exceed the default trigger level of 25 ug/L. In summary, there appears to be a consistent footprint of elevated total phosphorus concentrations detected in this water quality study extending over 250 m from the outfall.
Figure 4 - Burwood Beach Water Quality - Total Phosphorus
Burwood Beach Water Quality Assessment 15
Table 4 - Top 40 Total Phosphorus Concentrations per Area - Burwood Beach
(mg/L)
0-30 100 250 500-2000
0.045 0.062 0.032 0.038
0.04 0.044 0.025 0.034
0.04 0.042 0.023 0.022
0.038 0.036 0.022 0.02
0.034 0.036 0.022 0.02
0.034 0.033 0.022 0.018
0.032 0.032 0.021 0.018
0.031 0.03 0.02 0.018
0.03 0.03 0.02 0.018
0.028 0.026 0.02 0.017
0.027 0.026 0.02 0.017
0.026 0.024 0.02 0.017
0.026 0.024 0.019 0.016
0.026 0.023 0.018 0.016
0.026 0.023 0.018 0.016
0.025 0.023 0.018 0.016
0.025 0.022 0.018 0.015
0.024 0.022 0.018 0.015
0.024 0.022 0.017 0.015
0.024 0.022 0.017 0.015
0.023 0.022 0.016 0.015
0.023 0.02 0.016 0.015
0.023 0.02 0.016 0.014
0.023 0.02 0.015 0.014
0.022 0.019 0.015 0.014
0.022 0.018 0.015 0.014
0.022 0.018 0.015 0.014
0.022 0.018 0.015 0.013
0.022 0.018 0.015 0.012
0.021 0.017 0.014 0.012
0.021 0.017 0.014 0.012
0.02 0.017 0.014 0.012
0.019 0.017 0.014 0.012
0.019 0.017 0.014 0.012
0.019 0.016 0.014 0.011
0.018 0.016 0.013 0.011
0.018 0.016 0.013 0.011
0.018 0.016 0.013 0.011
0.018 0.016 0.013 0.011
0.018 0.016 0.013 0.011
Burwood Beach Water Quality Assessment 16
Chlorophyll-a Figure 5 shows the sorted chlorophyll-a concentrations for each of the four zones. The highest concentration was much the same in each zone. For most of the distribution the sorted chlorophyll-a measurements at the outfall and 100 m zone are a bit higher than at the 250 m and reference zones. It would not be expected that the soluble nutrients in the Burwood Beach effluent could be converted to phytoplankton (and thus increase chlorophyll levels) within a day or less. Thus no increase in chlorophyll-a level is expected at the outfall or surrounding zones. Table 5 lists the top 40 chlorophyll-a concentrations in the four zones. From the table, it is apparent that chlorophyll-a is higher at the outfall and 100 m zones. The reason for this is not known.
Figure 5 - Burwood Beach Water Quality - Chlorophyll-a
Burwood Beach Water Quality Assessment 17
Table 5- Top 40 Chlorophyll-a Concentrations per Area - Burwood Beach (mg/m3)
0-30 m 100 m 250 m 500-2000 m
3 3 3 2.3
3 3 2 2
2 2 2 2
2 2 2 2
2 2 2 2
2 2 2 1.8
2 2 1.6 1.4
2 2 1.5 1.3
2 2 1.4 1.1
2 2 1.2 1.1
2 2 1 1
2 2 1 0.9
2 1.9 1 0.8
2 1.6 1 0.8
1.7 1.3 1 0.8
1.4 1.2 1 0.8
1.3 1.1 1 0.7
1.3 1.1 1 0.7
1.2 1 1 0.7
1.1 1 1 0.7
1 1 0.9 0.6
1 1 0.9 0.5
1 1 0.9 0.5
1 0.9 0.9 <1.0
1 0.9 0.8 <1.0
1 0.9 0.7 <1.0
0.9 0.9 0.7 <1.0
0.9 0.9 0.6 <1.0
0.9 0.8 0.6 <1.0
0.9 0.8 0.6 <1.0
0.8 0.8 0.6 <1.0
0.8 0.7 0.6 <1.0
0.7 0.7 0.5 <1.0
0.7 0.7 0.5 <1.0
0.7 0.6 0.5 <1.0
0.7 0.6 <1.0 <1.0
0.7 0.6 <1.0 <1.0
0.7 0.6 <1.0 <1.0
0.7 0.6 <1.0 <1
0.6 0.6 <1.0 <1
Burwood Beach Water Quality Assessment 18
Enterococci Figure 6 shows the sorted enterococci concentrations for each of the four zones. The highest concentration was measured at the 100 m zone and for most of the distribution the sorted enterococci measurements at the outfall and 100 m zones are similar and generally higher than the levels at the 250 m and reference zones. The enterococci signature of the effluent and sludge are 900 and 6,300 cfu/100 m/L respectively. There appears to be a section of the range in Figure 6 where concentrations at the outfall zone are about 100 cfu/100 m/L higher than in the reference zone. This suggests a footprint of elevated enterococci at the outfall zone. Table 6 lists the top 40 enterococci concentrations in the four zones. From the table, there are many samples where the enterococci level in all zones (and especially near the outfall) exceeds an indicative level of 40 cfu/100 mL. This suggests elevated enterococci occurs over a wide area and the outfall is not the only source of enterococci. The 90 percentile concentrations for the four zones are 150 cfu/100 mL for Zone 1; 170 cfu/100 mL for Zone 2, 110 cfu/100 mL for Zone 3 and 50 cfu/100 mL for Zone 4. This suggests a footprint extending further than 250 m from the outfall. In summary, there appears to be a consistent footprint of elevated enterococci concentrations detected in this water quality study extending at least 500 m from the Burwood Beach outfalls, but much lower than the expected signature values.
Figure 6 - Burwood Beach Water Quality - Enterococci
Burwood Beach Water Quality Assessment 19
Table 6- Top 40 Enterococci Concentrations per Area - Burwood Beach
(CFU/100mL)
0-30 m 100 m 250 m 500-2,000 m
380 1000 200 370
370 1000 180 300
210 260 180 130
200 260 160 120
180 250 140 100
170 210 120 70
170 200 120 59
160 200 110 51
160 190 110 49
150 180 110 45
150 170 100 32
140 170 96 22
130 170 89 20
130 160 80 19
130 150 76 18
130 140 72 16
130 130 65 16
120 120 64 15
120 120 51 14
120 120 49 13
120 110 48 12
110 95 46 12
110 87 45 11
110 82 40 11
100 79 39 10
96 78 36 8
95 76 34 8
95 75 34 7
78 67 34 7
72 62 32 7
71 60 30 7
70 60 29 7
70 60 28 5
69 60 28 5
67 57 25 4
67 52 24 4
66 52 24 4
64 52 21 4
62 50 20 4
60 46 19 4
Burwood Beach Water Quality Assessment 20
Faecal Coliforms Figure 7 shows the sorted faecal coliform levels for each of the four zones. The highest level was measured in the outfall zone. There is a consistent trend in faecal coliform level with distance, with highest concentrations in the outfall zone, somewhat lower concentrations at 100 m distance, lower concentrations at 250 m distance and lowest concentrations in the 500 m-reference zone. The faecal coliform signature of the effluent and sludge are 14,000 and 28,000 cfu/100 m/L respectively. There appears to be a section of the range in Figure 6 where concentrations at the outfall zone are about 500 to 1,000 cfu/100 m/L higher than in the reference zone. This suggests a footprint of elevated faecal coliform at the outfall zone but much lower than the expected signature increment. Table 7 lists the top 40 faecal coliform concentrations in the four zones. There is a clear trend with a higher proportion of samples exceeding 200 cfu/100 mL at sites closer to the outfall. This suggests elevated faecal coliform levels occur over a wide area and the outfall may not be not the only source of faecal coliforms. The 90 percentile concentrations for the four zones are 500 cfu/100 mL for Zone 1; 300 cfu/100 mL for Zone 2, 150 cfu/100 mL for Zone 3 and 50 cfu/100 mL for Zone 4. This suggests a footprint extending further than 250 m from the outfall. In summary, there appears to be a consistent footprint of elevated faecal coliform concentrations detected in this water quality study extending at least 500 m from the Burwood Beach outfalls.
Figure 7 - Burwood Beach Water Quality - Faecal Coliforms
Burwood Beach Water Quality Assessment 21
Table 7- Top 40 Faecal Coliform Concentrations per Area - Burwood Beach
(CFU/100mL)
0-30 m 100 m 250 m 500-2,000 m
5500 2000 450 400
1400 1500 450 230
1200 680 440 200
1200 540 360 150
1200 410 290 140
1100 400 280 130
770 400 270 120
750 400 240 120
660 390 240 92
610 360 220 56
560 360 210 54
510 340 160 50
480 330 150 47
450 300 150 44
450 300 150 38
400 300 140 36
400 300 140 35
390 280 130 35
360 280 130 31
350 280 120 29
350 270 110 28
300 250 110 27
300 250 110 24
280 250 110 22
280 240 97 20
260 230 84 18
260 230 77 17
250 230 68 14
250 230 66 13
250 230 63 10
250 220 62 10
250 210 60 10
240 200 59 9
230 200 59 9
230 190 57 9
230 190 54 9
220 180 54 8
210 170 52 8
210 150 50 7
210 150 48 7
Burwood Beach Water Quality Assessment 22
Summary The purpose of the water quality monitoring was to characterise the changes to water quality in the area of the Burwood Beach outfalls as a result of the effluent discharge and to define the footprint of the changes. Based on this examination and interpretation of the raw water quality data, the following conclusions are drawn.
1. There is a clear and consistent footprint of elevated ammonia concentration detected in this water quality study which extends to 500 m from the outfalls.
2. The concentrations of oxidised nitrogen are elevated above the ANZECC default trigger levels in the four zones. This suggests a locally derived trigger would be higher than the default value.
3. Oxidised nitrogen appears to be more elevated at the outfall and 100 m zones compared to the reference zone, suggesting a footprint extending about 100 m from the outfall.
4. There appears to be a consistent footprint of elevated total nitrogen concentrations detected in this water quality study to more than 250 m from the outfall.
5. There appears to be a consistent footprint of elevated total phosphorus concentrations detected in this water quality study extending over 250 m from the outfall.
6. There appears to be a consistent footprint of elevated enterococci concentrations detected in this water quality study extending at least 500 m from the Burwood Beach outfalls
7. There appears to be a consistent footprint of elevated faecal coliform concentrations detected in this water quality study extending at least 500 m from the Burwood Beach outfalls.
8. In summary, the water quality data indicate a footprint of the outfall discharge extending to about 500 m from the outfall and possibly further for ammonia, total nitrogen, total phosphorus, enterocooci and faecal coliforms.
Regards, Ian Wallis