OEH NSW WATER LEVEL FREQUENCY DISTRIBUTION ANALYSIS

A division of the Department of Finance & Services

OEH NSW WATER LEVEL FREQUENCY DISTRIBUTION ANALYSIS Report MHL2100 March 2014

prepared for NSW Office of Environment and Heritage

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OEH NSW Water Level Frequency Distribution Analysis Report MHL2100 March 2014 Michael Galloway Functional Team Leader 110b King Street Manly Vale NSW 2093 T: 02 9949 0200 F: 02 9948 6185 E: [email protected] W: www.mhl.nsw.gov.au

mailto:[email protected]://www.mhl.nsw.gov.au/

Cover photograph: Flooded paddock near Aldavilla Downstream, 24 February 2013 Document Control

Issue/ Revision Author Reviewer

Approved for Issue Name Date

Draft 26/03/12 Sarah Hesse and Sarah Darvill, MHL

Ed Couriel, MHL

Draft 17/08/12 Sarah Darvill Kimbyl Mann and Peter Davidson, MHL Martin Fitzhenry, OEH

Final draft 16/12/13

Sarah Darvill and Erin Alley, MHL

Michael Galloway and Ed Couriel, MHL Martin Fitzhenry, OEH

Final 26/03/14 Sarah Darvill and Erin Alley, MHL

Michael Galloway, MHL

Ed Couriel, MHL 26/03/14

Crown in right of NSW through the Department of Finance & Services 2014

NSW Public Works Manly Hydraulics Laboratory and the NSW Office of Environment and Heritage permit this material to be reproduced, for educational or non-commercial use, in whole or in part, provided the meaning is unchanged and its source, publisher and authorship are acknowledged. While this report has been formulated with all due care, the State of New South Wales does not warrant or represent that the report is free from errors or omissions, or that it is exhaustive. The State of NSW disclaims, to the extent permitted by law, all warranties, representations or endorsements, express or implied, with regard to the report including but not limited to, all implied warranties of merchantability, fitness for a particular purpose, or non-infringement. The State of NSW further does not warrant or accept any liability in relation to the quality or accuracy of the report and no responsibility is accepted by the State of NSW for the accuracy, currency, reliability and correctness of any information in the report provided by the client or third parties.

Report No. MHL2100 PW Report No. 11080 ISBN 978 0 7347 4447 0 MHL File No. EDP8-2172 First published March 2014

Manly Hydraulics Laboratory is Quality System Certified to AS/NZS ISO 9001:2008.

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Foreword The NSW Office of Environment and Heritage (OEH) manages an extensive network of automatic water level recorders (AWLR) as part of its Floodplain, Estuary and Coastal Management programs. The coastal data network is operated and maintained by NSW Public Works Manly Hydraulics Laboratory (MHL) under an annual contract with OEH.

This report has been prepared by NSW Public Works Manly Hydraulics Laboratory for the NSW Office of Environment and Heritage, and presents information collected by NSW Public Works MHL at the majority of water level recording stations.

OEH has commissioned NSW Public Works MHL to conduct a summary review into water level frequency distribution. This report presents the details and findings of the study.

Data analysis and reporting was undertaken by Sarah Darvill. The report was overseen by Martin Fitzhenry from the Environmental Programs Branch, OEH.

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Summary NSW Public Works Manly Hydraulics Laboratory manages over 300 flood, estuary and ocean tide stations on behalf of the Office of Environment and Heritage. This report is a summary review of the frequency distribution of 235 stations.

The report presents the following:

a review of available stations and datasets for accuracy and validity for analysis statistical analysis of all available water level stations for the complete record of available

data frequency distribution analysis of available water level data for each station, together with

the ranking of highest and lowest recorded water levels compilation and presentation of results in table format graphical display of frequency distribution analysis brief comparison of frequency distribution results to tidal planes statistics, and brief discussion on the methodology and results and some recommendations on which

datasets may be appropriate for further analysis and frequency forecasting.

This report supplements the NSW Tidal Planes Analysis (MHL2053 October 2012).

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Contents 1. INTRODUCTION 1

1.1 Background 1 1.2 Study Objectives 1

2. WATER LEVEL STATIONS 2 2.1 Ocean Tide Stations 2 2.2 Estuary and Flood Stations 3

3. FREQUENCY DISTRIBUTION ANALYSIS METHODOLOGY 4 3.1 Interval Method 4 3.2 Tidal Plane Analysis 5

4. FREQUENCY DISTRIBUTION ANALYSIS RESULTS 6 4.1 Station Information 6 4.2 Summary Statistics 8 4.3 Frequency Distribution Tables 8

5. DISCUSSION AND LIMITATION OF RESULTS 10 5.1 Physical Influences on Frequency Distribution 10 5.2 Comparison to Tidal Planes 12 5.3 Limitations of Frequency Distribution Analysis 13

6. CONCLUSIONS AND RECOMMENDATIONS 14 6.1 Recommendations for Further Analysis 14

7. REFERENCES 15 APPENDICES A Data Summary Tables and Plots B Frequency Distribution Analysis Tables TABLES 3.1 Calculation of Tidal Planes 5 4.1 Datum Explanations 6 4.2 Summary of Datum Conversions 7 5.1 Stations Excluded from Report 12 FIGURES 2.1 Lord Howe Island Ocean Tide Gauge 2.2 Example of a Typical ICOLL Wollumboola Lake, South Coast 2.3 Flood-affected Grafton Station 2.4 Wyong Weir Upstream 4.1 Percentage Exceedance Plot Example Grafton 4.2 Log Percentage Exceedance Plot Example Grafton 4.3 Number of Data Points Plot Example Grafton 5.1 Example of Flood Duration

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1. Introduction

1.1 Background Since the 1940s, NSW Public Works Manly Hydraulics Laboratory has collected water level data at coastal and estuarine stations along the NSW coast. NSW Public Works MHL currently maintains a network of approximately 250 water level monitoring stations located in 34 coastal estuaries and coastal regions on behalf of the NSW Office of Environment and Heritage.

Water levels along the NSW coast and estuaries are subject to variation from regular tidal forcing, oceanographic and meteorological effects. However, one of the most significant drivers of water level fluctuation is flood events, varying from small to large events and occurring with less frequency than tidal, oceanographic and meteorological events.

Understanding the magnitude and recurrence of water levels outside of the tidal range is an essential component of risk analysis, protection strategy, design and resource management for the NSW coast. The need for this type of research has been highlighted in recent years with devastating floods affecting many Australians. A comprehensive knowledge of the varying water level responses along the NSW coastal estuaries can be gained from data supplied by the extensive network of water level recording stations operated by NSW Public Works MHL.

This report provides a frequency distribution analysis of recorded water levels at all available stations and provides the basis for an analysis of the recurrence of extreme water levels on the NSW coast.

1.2 Study Objectives The issues outlined in Section 1.1 above led to the formulation of the following study objectives relating to water level data:

1. review and quality assurance on all available data from NSW water level recording stations, up to and including June 2013

2. description of an appropriate frequency distribution method

3. calculation of frequency distribution for all water level stations including percentage exceedance

4. graphical display of frequency distribution analysis, and

5. comparison of tidal plane water levels, to calculated return periods.

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2. Water Level Stations NSW Public Works MHL maintains an extensive water level database for the NSW east coast that has been developed to support a number of OEH programs associated with floodplain, coastal and estuary management. NSW Public Works MHLs environmental data recording network consists of 50 estuary water level gauges, 170 flood water level gauges, 20 ocean tide gauges, 7 ocean wave buoys and 72 rainfall gauges, as well as water flow monitoring devices and anemometers. The water level gauges cover eastern NSW coastal basins including 107 rivers, creeks, lakes and lagoons, with over 30 years of electronic data at some stations. A summary of the physical characteristics and available tidal and hydrographic surveys for the estuaries of NSW is available from the Office of Environment & Heritage http://www.environment.nsw.gov.au/estuaries/list.htm).

NSW Public Works MHL collects data at these stations using a variety of techniques. Water level data is then transferred to a secure location via telemetry including internet protocol (IP), landline telephone, cellular networks and Event Reporting Radio Telemetry System (ERRTS).

Data is quality controlled by comparing nearby stations, overplotting with rainfall events in the region and making any adjustments required following a station visit from a field operator.

Included in this analysis is data from 45 estuary water level gauges, 170 flood water level gauges, and 20 ocean tide stations collected by NSW Public Works MHL. Some OEH water level stations managed by NSW Public Works MHL have been excluded from frequency distribution analysis due to an insufficient amount of quality data being available (generally less than a year).

Stations are classified into three categories: Ocean Tide Stations, Estuary Stations and Flood Stations. Appendix A identifies each station by classification.

2.1 Ocean Tide Stations NSW Public Works MHL operates 20 coastal and 4 offshore ocean tide stations. These stations are located in bays, harbours, at river entrances and offshore of major rivers. Most ocean tide water levels are recorded in local port datum, which is approximately Indian Spring Low Water (ISLW).

Due to their position outside of mainland Australia, poor datum relation information to land-based sites is available for Norfolk Island and Lord Howe Island (Figure 2.1). These two sites have been included in the following analysis.

Offshore stations have not been included in this report. These stations are least suited to this type of analysis due to each deployment being assigned a different Mean Sea Level datum (from a Foreman (1977) harmonic analysis). In 2012, the instrumentation of these stations was upgraded to RBR/Paros hardware and now log at five-minute intervals. Notwithstanding this, a lack of common datum makes this data unsuitable for frequency distribution analysis.

http://www.environment.nsw.gov.au/estuaries/list.htm

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2.2 Estuary and Flood Stations NSW Public Works MHL maintains 50 water level stations nominally classified as estuary stations, and 170 water level stations nominally classified as flood stations. Whilst nominally classified in this report by their characteristic location in estuary and river locations, these sites provide for a multitude of purposes (e.g. flood, tide, entrance management).

The 50 estuary stations maintained by NSW Public Works MHL are characterised by the mixing of fresh and salt water and are affected by tides and flooding from the upper reaches. Estuaries include ICOLLS which are defined as intermittently closed or open (coastal) lakes or lagoons. When closed, ICOLLS are more heavily influenced by flood waters than when open (Figure 2.2).

Estuaries in NSW vary in their shape and size, ranging from large coastal embayments and drowned river valleys such as Port Stephens and the Hawkesbury River, to coastal lakes such as Lake Macquarie and Wallis Lake, and smaller ICOLLS such as Cockrone Lake and Tabourie Lake.

The 170 flood stations maintained by NSW Public Works MHL are characterised by their position along the river and the effect rainfall has on the river conditions. These stations can be tidal influenced (Figure 2.3) or non-tidal such as sites upstream of a weir (Figure 2.4) or floodgate. These stations are the most sensitive to flooding and are key stations to flood alert notification and evacuation responses.

Management of flood stations plays an important role in providing warnings to local communities across the state. These stations enable the Bureau of Meteorology to provide predictions and advice to the State Emergency Service (SES) which enable the SES to produce flood warnings and evacuation advice to local councils and residents. The data collected by NSW Public Works MHL at flood stations throughout the state is used by stakeholders including local councils for floodplain management, flood risk analysis, modelling and prediction of floods.

Figure

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DRAWING 2100-02-01.cdr

2.1

MHL

LORD HOWE ISLAND OCEAN TIDE GAUGE

Figure

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2.2

MHL

EXAMPLE OF A TYPICAL ICOLL

WOLLUMBOOLA , SOUTH COASTLAKE

Figure

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2.3

MHL

FLOOD-AFFECTED GRAFTON STATION

Figure

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2.4

MHL

WYONG WEIR UPSTREAM

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3. Frequency Distribution Analysis Methodology It is important to note that information presented in this frequency distribution analysis is based on recorded data collected by NSW Public Works MHL only. As such, this frequency distribution analysis is the frequency of occurrence of a certain water level over the period of time that data is available.

The frequency distribution analysis has been conducted using the interval method, as described below. Frequency analysis is based on interval classes of 15-minute water levels recorded since the inception of the station. This method was based on the flood frequency method described in Pilgrim & Doran (1999).

Further investigation into the findings for each station is recommended to gain confidence in the accuracy and validity of the methodology prior to using the results for practical application. The frequency distribution method used in this report (Pilgrim & Doran 1999) was developed for United States flood data which is less variable than Australian flood data.

3.1 Interval Method The interval method has been used to categorise recorded water levels from a station into pre-defined classes to then calculate their frequency of occurrence. During initial testing, it was found that an interval of 0.1 m gave a detailed analysis for stations with large and small water level ranges. Following discussions between NSW Public Works MHL and OEH, it was decided that this interval of 0.1 m would be adopted for this study.

The number of data points falling into each interval for that range of data was determined. The number of points in each interval is then divided by the total number of points, which gives the frequency of occurrence of each interval for the data period available (see example below). The percentage exceedance is then calculated by counting the number of times the water level has exceeded that particular 0.1 m interval and then dividing this by the total number of exceedance values. This method is detailed in the following equations (Pilgrim & Doran 1999).

Definition Fi = F(ai < x bi) = mi/n

where Fi = frequency of data in the i'th interval x = data point k = interval i = interval serial number ai = lower limit of interval bi = upper limit of interval n = total number of data mi = total number of data in interval

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The sum of the frequency of all intervals is equal to one, as shown below:

k Fi = mi /n = n/n =1 i=1

Frequency of Exceedance: F(x > ai) = mi/n

3.2 Tidal Plane Analysis NSW Public Works MHL has recently completed a full tidal plane analysis on all tidal-affected OEH water level monitoring stations (MHL2053). That report covers the methodology and results for tidal stations from the Tweed region to the south coast of NSW.

To enable comparison of frequency distribution results to tidal planes, the following tidal constituents have been included in the results of this report for stations deemed tidal:

Mean High Water (MHW) Mean Sea Level (MSL) and Mean Low Water (MLW). These values can be found in the summary statistics section in Appendix A.

The formula for calculating these constituents can be found below. Refer to MHL2053 NSW Tidal Planes Analysis for detailed calculations of these and other tidal constituents.

Table 3.1 Calculation of Tidal Planes

Tidal Plane Equation

Mean High Water MHW = ZO + M2 Mean Sea Level MSL = ZO Mean Low Water MLW = ZO - M2

Tidal analysis is not presented in this report for monitoring locations where there was a lack of astronomical influence. This includes stations located upstream of the normal tidal limit or ICOLLS. Similarly, new monitoring locations with less than 150 days of continuous data records have also not had tidal analysis performed.

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4. Frequency Distribution Analysis Results The results of the frequency distribution analysis are presented in plot and table form summarising the frequency distribution for each station. A table of summary statistics for each station is also provided including the allocated Australian Water Resources Number (AWRC), location of the station and the commission date of each station.

For the purpose of this report, the NSW coastline has been divided into the following geographic regions:

Tweed Coffs Hunter Metropolitan South Coast.

4.1 Station Information The station information tables in each figure include information regarding the location and vertical datum of each station.

The mapping system used by NSW Public Works MHL for its station locations is the Map Grid Australia System (MGA). The majority of stations along the east coast fall in Zone 56, with stations from Bega River south in Zone 55.

While most stations are on Australian Height Datum, some stations are measured on a local datum. The following table provides a list of the datums and their abbreviated names which are used in the summary tables.

Table 4.1 Datum Explanations

Datum Abbreviated Name Assumed Datum N/A

Australian Height Datum AHD

Bermagui Local Hydro Datum BLHD

Brunswick River Flood Mitigation Datum BRFMD

Jervis Bay Port Datum JBPD

Coffs Port Datum CHPD

Crowdy Head Datum CHD

Cease To Flow of control structure CTF

Culvert Bed N/A

Forster Hydro Datum FHD

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Datum Abbreviated Name Iluka Port Datum N/A

Indian Spring Low Water ISLW

Local Water Resources Datum N/A

Lord Howe Island Tidal Datum N/A

Low Water Ordinary Spring Tide LWOST

Mean Sea Level MSL

Port Stephens Hydro Datum PSHD

Richmond River Valley Datum RRVD

Tweed River Hydro Datum TRHD

Weir Crest CTF

Zero Camp Cove ZCC An indicative adjustment of each station datum level to the local Australian Height Datum (AHD) is shown in Table 4.2. These adjustments were calculated circa 1990 by NSW Public Works using tidal harmonic analysis over a tidal epoch and a range ratio method over a limited date period. These values should be used with caution, as AHD levels are revised from time to time and improvements to GPS surveying techniques may provide additional refinement.

Table 4.2 Summary of Datum Conversions

River/Estuary Station Station Datum* Adjustment

to AHD Cobaki Broadwater Cobaki TRHD -0.863

Terranora Creek Dry Dock TRHD -0.875

Terranora Broadwater Terranora TRHD -0.853

Tweed River Tweed Heads TRHD -0.893

Tweed River Letitia 2A TRHD -0.886

Tweed River Barneys Point TRHD -0.883

Tweed River Tumbulgum TRHD -0.893

Tweed River North Murwillumbah TRHD -0.909

Tweed River Bray Park Weir TRHD -0.934

Tweed River Murwillumbah Bridge TRHD -0.909

Rous River Kynnumboon TRHD -0.926

Brunswick River Brunswick Heads BRFMD -0.046

Cudgen Creek Kingscliff BRFMD -0.066

Cudgen Lake Bogangar BRFMD -0.051

Marshalls Creek Orana Bridge BRFMD -0.024

Marshalls Creek Billinudgel BRFMD -0.019

Brunswick River Mullumbimby BRFMD -0.010

Richmond River Ballina LWOST -0.860

Richmond River Byrnes Point RRVD -0.857

Richmond River Wardell RRVD -0.824

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River/Estuary Station Station Datum* Adjustment

to AHD Richmond River Woodburn RRVD -0.815

Evans River Evans River Fishing Co-op RRVD -0.809

Evans River Iron Gates RRVD -0.819

Tucombil Canal Tucombil Highway Bridge RRVD -0.815

Tucombil Canal Tucombil Floodgate RRVD -0.815

Rocky Mouth Creek Rocky Mouth Creek RRVD -0.815

Richmond River Bungawalbin RRVD -0.809

Richmond River Coraki RRVD -0.815

Wilsons River East Gundurimba RRVD -0.831

Leycester Creek Tuncester RRVD -0.855

Wilsons River Woodlawn College RRVD -0.826

Clarence River Yamba IPD -0.895

Tasman Sea Coffs Harbour CHPD -0.882

Tasman Sea Crowdy Head Harbour CHD -0.911

Wallis Lake Entrance Forster FHD -1.061

Mallabula Mallabula Point PSHD -0.959

Port Stephens Tomaree PSHD -0.944

Port Jackson Sydney Port Jackson at HMAS Penguin Zero Camp Cove -0.925

Port Hacking Port Hacking ISLW -0.925

Jervis Bay HMAS Creswell JBPD -1.070

Bermagui Bermagui Harbour BLHD -0.714

Tasman Sea Eden Boat Harbour TBHD -0.924

4.2 Summary Statistics The summary statistics section in Appendix A provides information regarding the data for each station. This includes the start date of data collection, the highest water level record (and the date at which this occurred), and the lowest water level (and the date at which this occurred). Also included in this section are the values for Mean High Water (MHW), Mean Sea Level (MSL), and Mean Low Water (MLW).

4.3 Frequency Distribution Tables The frequency distribution tables in Appendix B present the results of the frequency distribution analysis. The water level is split into intervals (bins) of 0.1 m. This means an interval with a water level of 1.2 m will include all data points collected with a measured water level greater than 1.15 and less than or equal to 1.25 m.

The percentage exceedance is the percentage of time that a given value is exceeded http://www.mhl.nsw.gov.au/www/wave_glossary.html). The percentage exceedance plot (Figure 4.1) shows the percentage exceedance at 0.2 m is 50% in Grafton. This means that 50% of the time, water level will be above 0.2 m.

http://www.mhl.nsw.gov.au/www/wave_glossary.html

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The log percentage exceedance plot (Figure 4.2) is used to clearly show the large variation between 0-1% exceedance where floodwater levels change rapidly. The example used is Grafton, which has a non-flood range of between 0.0 m and 0.75 m. This would indicate that the majority of data points recorded for Grafton will be within this range. During floods, the water level can change quickly, meaning there are few points in the upper extreme water levels.

The number of data points plot (Figure 4.3) is used to show the number of times the recorded water level is within a class interval, for example, the number of times water level is between 0.15 and 0.25 m, for class interval 0.2 m. This is plotted on a log scale due to the large differences between numbers of observations. In floods there may be a few data points with extremely high water levels, but in a normal, non-flood situation, water levels will have a much smaller range and therefore a large number of data points in each interval. Figure 4.3 shows that in Grafton, the majority of data points fall between water levels of 0.0 m and 0.3 m.

For the majority of sites, the typical non-flood (tidal) water level range is between 0.0-2.0 m. To highlight the non-flood responses in water level, the number of data points plots have axis limits restricted to this range. Outside of this range, the number of data points can be more sporadic and therefore has not been shown in the plots. More information on the number of data points is presented in the Frequency Distribution tables in Appendix B.

Figure

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4.1

MHL

PERCENTAGE EXCEEDANCE PLOT EXAMPLE

GRAFTON

Highest water level record is 8.06m

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0 20 40 60 80 100

Wa

ter

Lev

el

(m)

Percentage Exceedance

50% of the recordedwater level exceeds 0.2m

Figure

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4.2

MHL

LOG PERCENTAGE EXCEEDANCE PLOT EXAMPLE

GRAFTON

Log percentage exceedance plot of Grafton where the log scale shows

the percentage change in the upper water levels

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0.001 0.01 0.1 1 10 100

Wa

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Lev

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(m)

Log Percentage Exceedance

Figure

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4.3

MHL

NUMBER OF DATA POINTS PLOT EXAMPLE

GRAFTON

-0.5

0.0

0.5

1.0

1 10 100 1000 10000 100000 1000000

Wa

ter

Le

ve

l (m

)

Number of Data Points

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5. Discussion and Limitation of Results

5.1 Physical Influences on Frequency Distribution Differences in the results between sites can be attributed to the various characteristics of the water body being analysed, while others are due to physical factors of the surrounding areas.

5.1.1 Ocean Tide Stations Ocean tide stations demonstrate a relatively symmetrical and bimodal distribution of water level observations, dominated by the semi-diurnal tide. This is illustrated by Norfolk Island, Figure A272 (number of data points plot) and Table B272, where all water level classes between 0.5-1.5 m have between approximately 40,00050,000 observations each, and bimodal maxima exist at 0.6 m and 1.3 m water levels. A decreasing number of observations is recorded in each water level class above and below the tidal range to the minimum and maximum recorded level.

These frequency distributions of the ocean tide stations are as expected for sites that are not significantly affected by floods or morphological changes and reflect tidal conditions dominated by the astronomical forcing processes.

5.1.2 Estuary Stations Estuary stations, particularly ICOLLs, do not follow the relatively symmetrical and bimodal distribution of water level observations in ocean tide stations, as a result of their physical conditions. By definition, when closed, ICOLLS are less influenced by tidal conditions than either open ICOLLS or ocean tide stations. They may experience periods of static water levels, governed by the entrance morphology, and may experience elevated water levels during low frequency flood events.

This is illustrated by Wollumboola Lake ICOLL Figure A232 (number of data points plot) and Table B232, which has a clear multimodal distribution (frequency maxima at 0.5 m, 1.2 m, 1.5 m, 1.7 m water levels), representing both non-flood and flood conditions. A decreasing number of observations is recorded in each water level class outside this range, to the minimum recorded level of -0.1 m and to the maximum recorded (flood) level of 2.6 m.

The frequency distributions of the estuary stations reflect the astronomical tidal forcing processes but can be dominated by morphological changes and flood events.

5.1.3 Flood Stations Inland flood stations such as weirs and stations upstream of tidal influence, typically show a completely asymmetrical distribution of water level observations. These sites may experience a very small normal water level range and relatively static water levels, governed by site conditions, and may experience dramatic water level increases during low frequency flood events.

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This is illustrated by Liverpool Weir, Figure A200 (number of data points plot) and Table B200, with a distinct modal maximum at 0.1 m in non-flood conditions and an asymmetric declining distribution outside this frequency maximum. A decreasing number of observations is recorded in each water level class to the minimum recorded level of -0.2 m and to the maximum recorded (flood) level of 4.47 m.

The frequency distributions of the flood stations are dominated by the localised site conditions and the flood events.

5.1.4 Anomalies A number of water level sites have differing frequency distributions due to physical factors of the surrounding areas. Three examples are provided to aid interpretation.

5.1.4.1 Ponded Minimum Levels

Ponded base levels are illustrated by Wallamba River at Nabiac, Figure A113 and Table B113, as a result of a downstream causeway. The site has an essentially unimodal distribution with a modal maximum at 5.5 m. A decreasing number of observations is recorded in each water level class to the maximum recorded (flood) level of 11.65 m and to minimum water levels of 5.0 m. However, in times of low water level, a ponded minimum level of 5.0 m records a greater number of observations in that water level class than the 5.1 m class.

Ponded base levels are also illustrated by Fairy Creek Upstream, Figure A208 and Table B208. In this case, the ponded modal maximum exists at a water level of 1.1 m, as a result of a downstream road bridge and channel narrowing. This is a higher elevation than Fairy Creek Downstream, Figure A209 and Table B209, with a modal maximum of 0.7 m.

5.1.4.2 Low Frequency Flood Events

Low frequency flood events with very small numbers of observations and graphical plotting artefacts are illustrated by Narrabeen Lagoon at Narrabeen Caravan Park, Figure A182 and Table B182. The record has a very small number of observations for maximum flood levels at 1.8 m and 1.9 m respectively, with only a single additional observation in the 1.9 m water level class compared with the 1.8 m water level class. Due to the log plot emphasising the 0-1% exceedance, the plot highlights this as a large visual difference. Due to the low number of observations this is not significant and symptomatic of event peak duration rather than frequency of event exceedance.

5.1.4.3 Estuary Entrance Management

The impact of entrance management regimes is illustrated by Wallaga Lake at Regatta Point, Figure A258 and Table B258, which has a multimodal frequency distribution. The modal maximum at 0.2 m corresponds to the mean (non-flood) condition. The modal maximum at 0.8 m corresponds to water level rises in the lake reached with flood events. A subsequent modal maximum at 1.2 m exists associated with higher magnitude, lower frequency flood events, which reach the height of 1.2 m or above. The water level associated with these events is largely arrested at a maximum of approximately 1.2 m, corresponding to the trigger level for the lakes artificial entrance breakout in Bega Valley Shire Councils lake management policy (MHL2129 July 2012).

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5.1.5 Excluded Stations The following stations (Table 5.1) have been excluded from analysis due to data issues which have affected the accuracy of the majority of the data, or the stations were assessed as being unsuitable for frequency analysis.

Table 5.1 Stations Excluded from Report

Station Issue The Avenue (Upstream and Downstream)

Data quality poor

Tuncurry Wetlands Predominantly dry Webbs Creek Data quality poor Missingham Bridge Data quality issues with historical data Hewitts Creek Entrance Survey mark issue being investigated Cabbage Tree Creek Upstream Poor data quality Byarong Creek Ongoing debris build-up and infrastructure limitations Mullet Creek Issue with data following bank collapse Balgownie Road Ongoing debris build-up and infrastructure limitations

5.1.6 Analysis Start Dates For some stations the analysis start date is different to the record start date. This is due to some historical data quality issues. While the data is on record, it has been coded as poor quality and excluded from this analysis. Refer to each figure for more detail.

5.2 Comparison to Tidal Planes Comparing the frequency of recorded water levels to tidal plane statistics differs slightly depending on what type of station is being analysed. The relationship between MSL and the 50% exceedance level is closer in stations which have less flood influence, such as stations classed as ocean tide stations, or where floods are short in duration. Stations which are more heavily influenced by longer duration floods show less of a relationship between the two. Because floods are removed for the tidal plane analysis, MSL will be less than the 50% exceedance level. MSL, MHW and MLW tidal planes are all defined in the summary statistics for each station in Appendix A.

For example:

Tomaree is classed as an ocean tide station on which inland flooding has negligible effect. This is reflected in the MSL (0.906 m) being similar to the 50% exceedance (0.940 m).

For flash flood stations where the rise and fall of water level is over a short duration such as Grafton and Kempsey, the high water levels only happen in 1% of the data therefore having less of an effect on the 50% exceedance. Grafton has an MSL of 0.16 m and a 50% exceedance of 0.2 m.

Wallis Creek Downstream has longer duration of floods due to the manipulation caused by floodgates and therefore the MSL differs more from the 50% exceedance than in other flood sites with shorter, flash floods. The MSL of Wallis Creek Downstream is 0.20 m compared to the 50% exceedance of 0.35 m.

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5.3 Limitations of Frequency Distribution Analysis The value of frequency distribution increases with the length of the data set. A longer data set is more likely to contain extreme events such as drought periods and floods. This information is better suited to assist stakeholders with planning and preparing in the likelihood of extreme events. Short data records do not have this advantage and are less suitable for this type of use.

One limitation with this frequency distribution analysis is the analysis does not take into account duration of water levels. For example, a single event may have multiple peak levels recorded (Figure 5.1(a), or only one or two (Figure 5.1(b)) thus it is important to consider that multiple entries in the higher water levels may be from a single event of a long duration. So statistics can be used to determine duration of exceedance (minutes/hours) rather than annual exceedance probabilities or average recurrence intervals of flood events.

A further limitation of this type of analysis is that it does not take into account any change in the catchment or recording conditions during which the data was obtained. Most of the stations used in this report are coastal or near coastal areas, both of which have experienced population and infrastructure growth in the past 30 years (Abel et al. 2011). Similarly, expected climate change and sea level rise means that frequency distributions based on observed water levels are unlikely to be representative of future water level exceedance statistics. Climate change, sea level rise, and this type of growth or change in infrastructure is likely to have an effect on the nearby waterways. This is especially important when using this data for future work.

Data for each station should be interpreted for that station based on the method of collection and the characteristics of the surrounding area. This would include being aware of any difference in datums used at each station, the length of the data set and the physical characteristics and hydrology at that station.

Figure

Report 2100


5.1

MHL

EXAMPLE OF FLOOD DURATION

a)

Time t15-01-2012 22-01-2012 29-01-2012 05-02-2012 12-02-2012 19-02-2012 26-02-2012 04-03-2012

Wate

rLeve

l[m

]

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6

8

Mount George (Live) / Mount George (Live) / Level 1 / 00 - Continuous.P

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b)

Time t29-02-2012 03-03-2012 06-03-2012 09-03-2012 12-03-2012 15-03-2012

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]

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Paterson Railway Bridge (Live) / Paterson Railway Bridge (Live) / Level 1 / 00 - Continuous.P

x x

MHL2100 - 14

6. Conclusions and Recommendations This report presents frequency distribution analysis for a range of ocean, estuary and flood stations on behalf of OEH. It supplements the tidal plane analysis report (MHL2053).

Frequency distribution analysis is advantageous as it is a relatively simple procedure and does not require separate analysis for rainfall or other factors, being based solely on previously recorded water level data. Station characteristics, site specific station issues involving location, datums and length of record all need to be taken into consideration when using this analysis.

6.1 Recommendations for Further Analysis It is recommended that to complement this type of analysis the next step would be

examining significant flood events and the duration at which water levels were recorded above a certain percent exceedance. This report does not take into account the duration of a specific flood event. Examining specific flood events, including rainfall and duration of peak water levels, would further stakeholders understanding of floods and assist with future planning.

As the majority of the data sets used in this report are no longer than 30 years, a recommendation would be to include historical flood data. This is when a flood has been recorded outside of the electronic data period and is usually the case for very large floods, for example the 1955 Hunter Valley flood. Such floods can provide valuable information, however it is important to determine the reliability of such records. Using flood marks recorded on old buildings, historical newspaper articles and photographs provide usable information.

NSW Public Works MHL recommends this type of analysis be updated regularly to assist with urban planning and risk analysis due to the increase in high level flooding and the devastating effect that has been seen in Australian communities in recent years. This, in conjunction with examining flood events, would provide stakeholders with an important tool when it comes to understanding flood event frequency in a specific area.

MHL2100 - 15

7. References Abel, N., Goddard, R., Harman, B., Leitch, A., Langridge, J., Ryan, A. & Heyenga, S. 2011,

Sea level rise, coastal development and planned retreat: analytical framework, governance principles and an Australian case study, Environmental Science & Policy, Volume 14, Issue 3, May 2011.

Foreman, M.G.G. 1977, Manual for Tidal Heights Analysis and Prediction, Pacific Marine Science Report 77-10, Institute of Ocean Sciences, Patricia Bay, Victoria BC.

MHL 2012, New South Wales Tidal Plane Analysis, NSW Public Works Manly Hydraulics Laboratory Report MHL2053.

MHL 2012, Highest Astronomical Tide Calculations for Essential Energy Powerline Crossings, NSW Public Works Manly Hydraulics Laboratory Report MHL2129.

MHL NSW Wave Climate Glossary http://www.mhl.nsw.gov.au/www/wave_glossary.htmlx

Pilgrim, D.H. and Doran, D.G. 1999, Selection and Evaluation of Parent Distributions, Flood Frequency Analysis, CRC Press, eds. A. Ramachandra Rao and Khaled H. Hamed, October 1999.

http://www.mhl.nsw.gov.au/www/wave_glossary.htmlxhttp://www.crcnetbase.com/doi/abs/10.1201/9781420048636.ch2

MHL2100

Appendix A

Data Summary Tables and Plots

MHL2100 - A1

Appendix A Data Summary Tables and Plots River/Estuary System Station Name Station Classification

Station No. MGA Easting Northing

Figure No.

Station Locality Map A1 Broadwater Cobaki F 201448 56 549348 6883136 A2 Terranora Inlet Dry Dock F 201428 56 550723 6881231 A3 Tweed River Terranora F 201447 56 548954 6880379 A4 Tweed River Tweed Heads 0 201470 56 553958 6883904 A5 Tweed River Letitia 2A F 201429 56 554314 6882414 A6 Tweed River Barneys Point F 201426 56 554111 6877720 A7 Tweed River Tumbulgum F 201432 56 545172 6871996 A8 Tweed River North Murwillumbah F 201420 56 539327 6866474 A9 Tweed River Bray Park Weir F 201455 56 536209 6864484 A10 Tweed River Murwillumbah Bridge F 201465 56 539219 6866353 A11 Rous River Kynnumboon F 201422 56 538179 6867895 A12 Cudgen Lake Bogangar F 202416 56 554672 6866411 A13 Cudgen Lake Kingscliff F 202418 56 557069 6873909 A14 Station Locality Map A15 Marshalls Creek Orana Bridge F 202475 56 553607 6845533 A16 Marshalls Creek Billinudgel F 202400 56 551554 6847116 A17 Brunswick River Brunswick Heads O 202403 56 554014 6843206 A18 Brunswick River Mullumbimby F 202402 56 548580 6841766 A19 Station Locality Map A20 Lennox Head Lake Ainsworth E 203455 56 557863 6816160 A21 Richmond River Ballina Breakwall O 202471 56 556826 6805737 A22 Richmond River Byrnes Point F 203461 56 551356 6805879 A23 Richmond River Wardell F 203468 56 545287 6797087 A24 Richmond River Woodburn F 203412 56 533495 6784077 A25 Evans River Evans River Fishing Co-op E 203462 56 542200 6778355 A26 Evans River Iron Gates F 203475 56 539691 6778224 A27 Tucombil Canal Tucombil Highway Bridge E 203480 56 532968 6782590 A28 Tucombil Canal Tucombil Floodgate F 203434 56 534025 6781669 A29 Rocky Mouth Creek Rocky Mouth Creek F 203432 56 531750 6781327 A30 Richmond River Bungawalbin F 203450 56 527019 6788273 A31 Richmond River Coraki F 203403 56 527976 6793772 A32 Wilsons River East Gundurimba F 203427 56 526040 6809083 A33 Leycester Creek Tuncester F 203443 56 523436 6814670 A34 Wilsons River Woodlawn College F 203402 56 529523 6815746 A35 Station Locality Map A36 Clarence River Yamba O 204470 56 535140 6744425 A37 Clarence River Oyster Channel F 204451 56 530499 6744302 A38 Clarence River Maclean F 204410 56 519006 6741469 A39 Clarence River Lawrence F 204453 56 510257 6736953 A40 Clarence River Tyndale F 204465 56 512565 6729208 A41 Clarence River Brushgrove F 204406 56 507517 6729106 A42 Clarence River Ulmarra F 204480 56 502596 6722105 A43 Clarence River Grafton F 204400 56 493398 6715149 A44

MHL2100 - A2

River/Estuary System Station Name Station Classification Station

No. MGA Easting Northing Figure

No. Clarence River Rogans Bridge F 204414 56 488813 6723401 A45 Palmers Channel Palmers Island Bridge F 204426 56 525780 6744108 A46 Lake Wooloweyah Lake Wooloweyah F 204485 56 533141 6739053 A47 Station Locality Map A48 Wooli River Wooli Caravan Park F 205463 56 524551 6697797 A49 Wooli River Wooli Entrance F 205462 56 525689 6693350 A50 Corindi Creek Red Rock E 205450 56 521903 6683088 A51 Woolgoolga Lake Woolgoolga Lake E 205455 56 519091 6669486 A52 Woolgoolga Creek Woolgoolga F 205441 56 515783 6668247 A53 Moonee Creek Moonee Creek E 205435 56 514953 6658959 A54 Station Locality Map A55 Tasman Sea Coffs Harbour O 205470 56 514044 6647646 A56 Coffs Creek Coffs Creek Highway Bridge F 205439 56 511160 6648716 A57 Newports Creek Newports Creek F 205460 56 510023 6645653 A58 Boambee Creek Boambee F 205438 56 507835 6643805 A59 Boambee Creek Boambee Entrance E 205475 56 509887 6642047 A60 Station Locality Map A61 Bonville Creek Bonville E 205480 56 503975 6640378 A62 Bellinger River Repton F 205403 56 502371 6632225 A63 Bellinger River Bellingen Bridge F 205442 56 490338 6631222 A64 Kalang River Urunga F 205407 56 501230 6626819 A65 Kalang River Upstream Newry Island F 205458 56 497967 6625224 A66 Kalang River Kooroowi F 205440 56 482965 6629668 A67 Station Locality Map A68 Deep Creek Deep Creek E 205485 56 500255 6613429 A69 Nambucca River Stuarts Island F 205465 56 499274 6608252 A70 Nambucca River Stuarts Island Downstream F 205466 56 499502 6608568 A71 Nambucca River Macksville F 205416 56 492382 6602959 A72 Nambucca River Utungun F 205414 56 485797 6600328 A73 Nambucca River Bowraville Downstream F 205425 56 486768 6608695 A74 Station Locality Map A75 Borirgala Creek Borirgala Creek E 206450 56 496445 6586064 A76 Macleay River South West Rocks F 206456 56 501638 6582579 A77 Korogoro Creek Hat Head E 206465 56 505441 6564016 A78 Saltwater Lagoon Saltwater Lagoon E 206460 56 506119 6582610 A79 Macleay River Smithtown F 206406 56 494957 6568644 A80 Macleay River Kempsey F 206402 56 485099 6561395 A81 Macleay River Euroka Upstream F 206458 56 478817 6560507 A82 Macleay River Aldavilla Downstream F 206459 56 479318 6561231 A83 Killick Creek Crescent Head E 207452 56 497704 6549628 A84 Station Locality Map A85 Maria River Green Valley F 207406 56 486422 6540062 A86 Wilson River Telegraph Point F 207415 56 481049 6534532 A87 Hastings River Port Macquarie O 207422 56 491540 6523094 A88 Hastings River Settlement Point F 207418 56 490637 6525308 A89 Hastings River Dennis Bridge Downstream F 207444 56 482995 6525235 A90 Hastings River Wauchope Railway Bridge F 207401 56 474989 6520179 A91

MHL2100 - A3

River/Estuary System Station Name Station Classification


Figure No.

Station Locality Map A92 Lake Cathie Lake Cathie F 207441 56 486160 6509676 A93 Camden Haven North Haven F 207423 56 483135 6499421 A94 Stingray Creek West Haven F 207437 56 480664 6499768 A95 Camden Haven Laurieton F 207425 56 480921 6497738 A96 Camden Haven Logans Crossing F 207428 56 470912 6502301 A97 Queens Lake Lakewood F 207475 56 477447 6500580 A98 Watson Taylors Lake Watson Taylors Lake F 207480 56 475577 6491073 A99 Station Locality Map A100 Tasman Sea Crowdy Head O 208470 56 476422 6477357 A101 Manning River Harrington F 208425 56 470255 6473391 A102 Manning River Croki F 208404 56 461589 6473115 A103 Manning River Dumaresq Island F 208430 56 454338 6470466 A104 Manning River Taree F 208410 56 448684 6468641 A105 Manning River Wingham F 208400 56 440523 6473219 A106 Manning River Mount George F 208440 56 419224 6472247 A107 Dingo Creek Munyaree Flat F 208019 56 433247 6477061 A108 Manning River Farquhar Inlet F 208415 56 461883 6466004 A109 Station Locality Map A110 Wallis Lake Entrance Forster O 209470 56 453635 6440173 A111 Wallamba River Tuncurry F 209401 56 450567 6442277 A112 Wallamba River Nabiac F 209404 56 436821 6446458 A113 Wallis Lake Tiona F 209403 56 454412 6425971 A114 Smiths Lake Tarbuck Bay E 209465 56 451573 6417932 A115 Myall River Bulahdelah F 209460 56 425452 6413412 A116 Myall River Bombah Point E 209475 56 434680 6403299 A117 Station Locality Map A118 Myall River Tea Gardens E 209480 56 421723 6385111 A119 Karuah River Karuah E 209485 56 403412 6386511 A120 Karuah River Mallabula Point F 209461 56 407770 6379227 A121 Port Stephens Tomaree O 209471 56 423362 6380025 A122 Station Locality Map A123 Hunter River Stockton Bridge F 210456 56 386238 6360819 A124 Hunter River Hexham Bridge F 210448 56 376564 6368158 A125 Williams River Raymond Terrace F 210452 56 382352 6375361 A126 Williams River Seaham F 210462 56 381105 6385316 A127 Hunter River Green Rocks F 210432 56 377459 6378142 A128 Hunter River Morpeth F 210430 56 371588 6378480 A129 Hunter River McKimms Corner F 210455 56 368162 6378933 A130 Hunter River Belmore Bridge F 210458 56 364435 6377790 A131 Hunter River Bolwarra Downstream F 210451 56 365589 6380214 A132 Hunter River Bolwarra Upstream F 210459 56 365825 6381148 A133 Hunter River Oakhampton Railway Bridge F 210475 56 365870 6381614 A134 Station Locality Map A135 Paterson River Hinton Bridge F 210410 56 373299 6379603 A136 Paterson River Dunmore F 210409 56 369238 6383269 A137 Paterson River Paterson Railway Bridge F 210406 56 370303 6392399 A138 Paterson River Gostwyck F 210402 56 369104 6396070 A139

MHL2100 - A4



Figure No.

Station Locality Map A140 Wallis Creek Wallis Creek Upstream F 210457 56 366405 6376968 A141 Wallis Creek Wallis Creek Downstream F 210428 56 366448 6376992 A142 Wallis Creek Louth Park F 210453 56 363251 6373693 A143 Station Locality Map A144 Lake Macquarie Marmong Point F 211460 56 370993 6350369 A145 Cockle Creek Cockle Railway Station F 211455 56 371200 6354217 A146 Cockle Creek Barnsley Vale F 211450 56 369036 6354808 A147 Lake Macquarie Belmont F 211461 56 374284 6343456 A148 Lake Macquarie Swansea Channel E 211462 56 373164 6338262 A149 Dora Creek Kalang Road F 211475 56 358978 6338962 A150 Dora Creek Cooranbong F 211470 56 355427 6339065 A151 Stockton Creek Morisset F 211480 56 357710 6336566 A152 Station Locality Map A153 Wallarah Creek Wallarah Creek Bridge F 211420 56 360911 6323585 A154 Tuggerah Lake Toukley F 211401 56 362602 6318536 A155 Wyong River Wyong Weir Upstream F 211417 56 351596 6316779 A156 Ourimbah Creek Lees Bridge F 211425 56 353685 6311531 A157 Tuggerah Lake Long Jetty F 211418 56 358753 6308079 A158 Tumbi Umbi Creek Tumbi Umbi F 211419 56 355321 6307476 A159 Station Locality Map A160 Narara Creek Manns Road F 211435 56 345890 6302955 A161 Wamberal Lagoon Wamberal Lagoon E 212451 56 355529 6300279 A162 Terrigal Lagoon Terrigal Bridge E 212456 56 355075 6298654 A163 Avoca Lagoon Avoca Lagoon E 212453 56 354060 6296250 A164 Cockrone Lake Cockrone Lake E 212454 56 353833 6292959 A165 Worthing Ave Creek Erina F 212436 56 350148 6299625 A166 Erina Creek Punt Bridge F 212433 56 347514 6298928 A167 Brisbane Water Ettalong F 212423 56 346015 6290156 A168 Brisbane Water Koolewong F 212422 56 344273 6295029 A169 Station Locality Map A170 Hawkesbury River Patonga O 212440 56 339822 6286295 A171 Hawkesbury River Spencer F 212431 56 327774 6296500 A172 Hawkesbury River Gunderman Caravan Park F 212429 56 319442 6298154 A173 Hawkesbury River Colo Junction F 212407 56 303218 6298170 A174 Hawkesbury River Sackville F 212406 56 303238 6292029 A175 Hawkesbury River Ebenezer F 212427 56 304385 6286031 A176 Hawkesbury River Windsor F 212426 56 297588 6279510 A177 Hawkesbury River Freemans Reach F 212410 56 294015 6283340 A178 Nepean River Castlereagh F 212404 56 284502 6275962 A179 Station Locality Map A180 Narrabeen Lagoon Narrabeen Bridge F 213422 56 342174 6268454 A181 Narrabeen Lagoon Narrabeen Caravan Park F 213408 56 342657 6269537 A182 Dee Why Lagoon Dee Why F 213424 56 342725 6264718 A183 Curl Curl Lagoon Curl Curl E 213426 56 342094 6262459 A184 Manly Lagoon Riverview Parade F 213413 56 340497 6260441 A185 Manly Lagoon Queenscliff Bridge F 213414 56 340963 6260561 A186 Port Jackson Sydney O 213470 56 338842 6255836 A187

MHL2100 - A5



Figure No.

Station Locality Map A188 Cooks River Canterbury Road F 213411 56 325928 6245842 A189 Cooks River Illawarra Road Bridge F 213420 56 328303 6244862 A190 Cooks River Tempe Bridge F 213415 56 329697 6244234 A191 Station Locality Map A192 Georges River Picnic Point Downstream F 213410D 56 315265 6238001 A193 Georges River Como Bridge F 213425 56 321829 6236499 A194 Georges River Milperra F 213405 56 313215 6244082 A195 Prospect Creek Lansdowne Bridge F 213402 56 312045 6248145 A196 Georges River Lansvale F 213401 56 311147 6247104 A197 Cabramatta Creek Irelands Bridge F 213407 56 309832 6246486 A198 Georges River Scrivener Street F 213404 56 309154 6244537 A199 Georges River Liverpool Weir F 213400 56 308517 6244021 A200 Port Hacking Port Hacking O 213473 56 328938 6227765 A201 Station Locality Map A202 Hewitts Creek Hewitts Creek Upstream F 214410 56 308181 6200426 A203 Hewitts Creek Hewitts Creek Downstream F 214411 56 308184 6200405 A204 Towradgi Creek Towradgi Creek Upstream F 214477 56 307607 6193622 A205 Towradgi Creek Towradgi Creek

Downstream F 214475 56 307627 6193619 A206

Cabbage Tree Creek Cabbage Tree Creek Downstream

F 214406 56 306268 6191829 A207

Fairy Creek Fairy Creek Upstream F 214403 56 306318 6189986 A208 Fairy Creek Fairy Creek Downstream F 214404 56 306351 6189963 A209 Byarong Creek Koloona Avenue Upstream F 214425 56 302908 6189424 A210 Byarong Creek Koloona Avenue

Downstream F 214426 56 302933 6189410 A211

American Creek Blackmans Parade Upstream

F 214430 56 301028 6185319 A212

American Creek Blackmans Parade Downstream

F 214431 56 301047 6185314 A213

Station Locality Map A214 Lake Illawarra Koonawarra Bay F 214440 56 299397 6179537 A215 Lake Illawarra Cudgeree Bay F 214416 56 303934 6177233 A216 Lake Illawarra Lake Illawarra Entrance F 214417 56 304479 6176070 A217 Macquarie Rivulet Princes Highway F 214402 56 296808 6174979 A218 Station Locality Map A219 Little Lake Little Lake F 214466 56 304058 6173347 A220 Minnamurra River Minnamurra E 214442 56 303004 6167226 A221 Werri Lagoon Werri Lagoon E 214445 56 301816 6155035 A222 Crooked River Gerroa E 215410 56 299419 6150158 A223 Station Locality Map A224 Shoalhaven River Shoalhaven Heads E 215470 56 293866 6140750 A225 Shoalhaven River Hay Street F 215415 56 292468 6140163 A226 Shoalhaven River Terara F 215420 56 283254 6139527 A227 Shoalhaven River Nowra Bridge F 215411 56 280834 6139284 A228 Shoalhaven River Gradys E 215452 56 268167 6137627 A229 Crookhaven River Crookhaven Heads O 215471 56 295273 6135157 A230 Shoalhaven River Greenwell Point F 215417 56 293193 6134898 A231 Wollumboola Lake Wollumboola E 215454 56 295853 6131507 A232

MHL2100 - A6



Figure No.

Station Locality Map A233 Currarong Creek Currarong Creek E 216405 56 301142 6122850 A234 Jervis Bay Jervis Bay O 216470 56 291107 6111022 A235 St Georges Basin Island Point E 216415 56 280751 6113506 A236 Sussex Inlet Sussex Inlet F 216412 56 280909 6105518 A237 Swan Lake Swan Lake E 216425 56 277908 6102580 A238 Station Locality Map A239 Lake Conjola Lake Conjola E 216420 56 272441 6094313 A240 Narrawallee Inlet Narrawallee E 216430 56 269839 6090673 A241 Tasman Sea Ulladulla Boat Harbour O 216471 56 270711 6084371 A242 Burrill Lake Burrill Lake Bridge F 216435 56 267949 6080929 A243 Lake Tabourie Lake Tabourie E 216440 56 264316 6074948 A244 Station Locality Map A245 Durras Lake Durras Lake E 216445 56 255304 6052185 A246 Clyde River Nelligen F 216453 56 241337 6050937 A247 Clyde River Princess Jetty O 216410 56 244680 6045169 A248 Station Locality Map A249 Tomaga River George Bass Drive E 216455 56 245153 6031716 A250 Moruya River Moruya Bridge F 217410 56 236703 6022312 A251 Moruya River Moruya Hospital F 217402 56 235673 6022790 A252 Station Locality Map A253 Tuross River Coila Lake E 218405 56 242275 6006878 A254 Tuross River Tuross Head E 218410 56 240903 6005119 A255 Station Locality Map A256 Wagonga Inlet Barlows Bay E 218415 56 239467 5988955 A257 Wallaga Lake Regatta Point E 219405 56 236890 5971052 A258 Station Locality Map A259 Bermagui Harbour Bermagui O 219470 56 237458 5964777 A260 Bega River Bega River E 219410 55 766036 5933971 A261 Station Locality Map A262 Back Lagoon Back Lagoon E 219415 55 759860 5914068 A263 Merimbula Lake Merimbula Wharf F 220410 55 759306 5913042 A264 Merimbula Lake Merimbula Lake F 220405 55 756507 5913260 A265 Pambula Lake Pambula Lake F 220415 55 756744 5905022 A266 Lake Curalo Lake Curalo E 220420 55 758419 5895363 A267 Tasman Sea Eden Boat Harbour O 220470 55 758550 5893255 A268 Wonboyn Lake Agnew Wharf E 220425 55 759154 5873229 A269 Station Locality Map A270 Tasman Sea Lord Howe Island O 240402 57 5924427 4864084 A271 Tasman Sea Norfolk Island O 240401 58 787578 6781947 A272 Station Classification: E Estuary station F Flood station O Ocean tide station

Figure

Report 2100

DRAWING 2100-A1.cdr

A1

MHL

STATION LOCATIONS

TWEED RIVER REGION

0 10km

Scale 1:250 000

Map courtesy of AUSLIG

N

Letitia 2A

Cobaki

Dry DockTerranora

Barneys Point

Kingscliff

Bogangar

Tumbulgum

Kynnumboon

Murwillumbah Bridge

North Murwillumbah

Bray Park Weir

Tweed Heads

Figure

Report 2100

A2

MHLNSW WATER LEVEL

FREQUENCY DISTRIBUTION ANALYSIS

BROADWATER AT COBAKI

Notes:

Refer to Appendix B for frequency distribution

analysis table.

*The information supplied has been collected

for use by the Office of Environment &

Heritage, and the water levels only

approximately relate to Australian Height

Datum (AHD) or other specified datum.

Other users should independently verify the

suitability of this data for their particular use.

Station Information

River/Estuary SystemBroadwater atCobaki

AWRC No. 201448

Station name Cobaki

Datum TRHD*

MGA Zone 56

Easting 549348

Northing 6883136

Summary Statistics

Time Interval (mins) 15

Record start date 12/12/1987

Highest water levelrecorded (m)

2.80

Date recorded 30/06/2005

Lowest water levelrecorded (m)

0.16

Date recorded 05/09/200224/01/200425/12/2006

Tidal plane annualaverage record

1990-2010

MHW (m) 1.19

MSL (m) 0.92

MLW (m) 0.64

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2.32



0.17



1990-2010

MHW (m) 1.23

MSL (m) 0.95

MLW (m) 0.67

Figure

Report 2100

A3

MHLNSW WATER LEVEL


TERRANORA INLET AT DRY DOCK

Station Information

River/Estuary System Terranora Inlet

AWRC No. 201428

Station name Dry Dock

Datum TRHD*

MGA Zone 56

Easting 550723

Northing 6881231

Notes:


analysis table.








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Report 2100

A4

MHLNSW WATER LEVEL


TWEED RIVER AT TERRANORA

Station Information

River/Estuary System Tweed River

AWRC No. 201447

Station name Terranora

Datum TRHD*

MGA Zone 56

Easting 548954

Northing 6880379

Summary Statistics




2.47



0.30

Date recorded 28/05/199116/12/199420/12/1994


1990-2010

MHW (m) 1.22

MSL (m) 0.96

MLW (m) 0.70

Notes:


analysis table.








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Report 2100

A5

MHLNSW WATER LEVEL


TWEED HEADS

Station Information


AWRC No. 201470

Station name Tweed Heads

Datum TRHD*

MGA Zone 56

Easting 553958

Northing 6883904

Summary Statistics




2.49



-0.15

Date recorded 16/09/199717/09/1997


1990-2010

MHW (m) 1.35

MSL (m) 0.89

MLW (m) 0.43

Notes:

Data loss September 1992-December 1993

and February 2000 to June 2002.


analysis table.








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A6

MHLNSW WATER LEVEL


TWEED RIVER AT LETITIA 2A

Station Information


AWRC No. 201429

Station name Letitia2A

Datum TRHD*

MGA Zone 56

Easting 554314

Northing 6882414

Summary Statistics




2.47



0.09



1990-2010

MHW (m) 1.30

MSL (m) 0.93

MLW (m) 0.56

Notes:


analysis table.








DRAWING 2100-A1.cdr

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Figure

Report 2100

A7

MHLNSW WATER LEVEL


TWEED RIVER AT BARNEYS POINT

Station Information


AWRC No. 201426

Station name Barneys Point

Datum TRHD*

MGA Zone 56

Easting 554111

Northing 6877720

Summary Statistics




2.66



0.19



1990-2010

MHW (m) 1.24

MSL (m) 0.94

MLW (m) 0.64

Notes:


analysis table.








DRAWING 2100-A1.cdr

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Figure

Report 2100

A8

MHLNSW WATER LEVEL


TWEED RIVER AT TUMBULGUM

Station Information


AWRC No. 201432

Station name Tumbulgum

Datum TRHD*

MGA Zone 56

Easting 545172

Northing 6871996

Summary Statistics




4.08



0.32



1990-2010

MHW (m) 1.33

MSL (m) 1.01

MLW (m) 0.70

Notes:

Low levels not recorded from 2002-2013.


analysis table.








DRAWING 2100-A1.cdr

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ter

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Figure

Report 2100

A9

MHLNSW WATER LEVEL


TWEED RIVER AT NORTH MURWILLUMBAH

Notes:

Data loss December 1988 to March 1992.


analysis table.








Station Information


AWRC No. 201420

Station nameNorthMurwillumbah

Datum TRHD*

MGA Zone 56

Easting 539327

Northing 6866474

Summary Statistics




5.90



0.26



1990-2010

MHW (m) 1.36

MSL (m) 1.01

MLW (m) 0.67

DRAWING 2100-A1.cdr

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ter

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Figure

Report 2100

A10

MHLNSW WATER LEVEL


TWEED RIVER AT BRAY PARK WEIR

Station Information


AWRC No. 201455

Station name Bray Park Weir

Datum TRHD*

MGA Zone 56

Easting 536209

Northing 6864484

Summary Statistics




7.88



0.99



N/A

MHW (m) N/A

MSL (m) N/A

MLW (m) N/A

Notes:


analysis table.








DRAWING 2100-A1.cdr

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Figure

Report 2100

A11

MHLNSW WATER LEVEL


TWEED RIVER AT MURWILLUMBAH BRIDGE

Station Information


AWRC No. 201465

Station nameMurwillumbahBridge

Datum TRHD*

MGA Zone 56

Easting 539219

Northing 6866353

Summary Statistics




5.61



0.36

Date recorded 29/07/200418/08/200518/08/200928/11/2012


2003-2010

MHW (m) 1.41

MSL (m) 1.06

MLW (m) 0.70

Notes:


analysis table.








DRAWING 2100-A1.cdr

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ter

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ter

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Figure

Report 2100

A12

MHLNSW WATER LEVEL


ROUS RIVER AT KYNNUMBOON

Station Information

River/Estuary System Rous River

AWRC No. 201422

Station name Kynnumboon

Datum TRHD*

MGA Zone 56

Easting 538179

Northing 6867895

Summary Statistics




5.4



0.35



1990-2010

MHW (m) 1.40

MSL (m) 1.06

MLW (m) 0.72

Notes:

Station temporarily decommissioned

from August 2002 to April 2004.


analysis table.








DRAWING 2100-A1.cdr

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Figure

Report 2100

A13

MHLNSW WATER LEVEL


CUDGEN LAKE AT BOGANGAR

Station Information

River/Estuary System Cudgen Lake

AWRC No. 202416

Station name Bogangar

Datum BRFMD*

MGA Zone 56

Easting 554672

Northing 6866411

Summary Statistics

Time interval (mins) 15



3.28



0.06

Date recorded14/01/199115/01/1991


N/A

N/A

N/A

N/AMHW (m)

MSL (m)

MLW (m)

Notes:


analysis table.








DRAWING 2100-A1.cdr

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ter

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el

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Figure

Report 2100

A14

MHLNSW WATER LEVEL


CUDGEN CREEK AT KINGSCLIFF

Station Information

River/Estuary System Cudgen Creek

AWRC No. 202418

Station name Kingscliff

Datum BRFMD*

MGA Zone 56

Easting 557069

Northing 6873909

Summary Statistics




1.44



-0.86

Date recorded11/08/199930/03/2006


1990-2008

MHW (m) 0.51

MSL (m) 0.05

MLW (m) -0.40

Notes:

Data loss July 2009 to May 2011 due to

siltation issues.


analysis table.








DRAWING 2100-A1.cdr

-1.0

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Figure

Report 2100

DRAWING 2100-A15.cdr

A15

MHL

STATION LOCATIONS

BRUNSWICK RIVER REGION

010km

Scale

1:2

50 0

00

Map c

ourt

esy o

fA

US

LIG

N

Mullu

mbim

by

Bill

inudgel Ora

na B

ridge

Bru

nsw

ick

Heads

Figure

Report 2100

A16

MHLNSW WATER LEVEL


MARSHALLS CREEK AT ORANA BRIDGE

Station Information

River/Estuary System Marshalls Creek

AWRC No. 202475

Station name Orana Bridge

Datum BRFMD*

MGA Zone 56

Easting 553607

Northing 6845533

Summary Statistics




2.19



-0.28



2003-2010

MHW (m) 0.52

MSL (m) 0.24

MLW (m) -0.04

Notes:


analysis table.









-0.5

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Wa

ter

Le

ve

l (m

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ter

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0.0

0.5

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2.0

2.5

0.001 0.01 0.1 1 10 100

Wa

ter

Lev

el

(m)


Figure

Report 2100

A17

MHLNSW WATER LEVEL


MARSHALLS CREEK AT BILLINUDGEL

Station Information

River/Estuary System Marshalls Creek

AWRC No. 202400

Station name Billinudgel

Datum BRFMD*

MGA Zone 56

Easting 551554

Northing 6847116

Summary Statistics




4.38



-0.10



1990-2010

MHW (m) 0.38

MSL (m) 0.29

MLW (m) 0.20

Notes:


analysis table.









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ter

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(m)


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5.0

0.0001 0.001 0.01 0.1 1 10 100

Wa

ter

Lev

el

(m)


Figure

Report 2100

A18

MHLNSW WATER LEVEL


BRUNSWICK RIVER AT BRUNSWICK HEADS

Notes:


analysis table.








Station Information

River/Estuary System Brunswick River

AWRC No. 202403

Station name Brunswick Heads

Datum BRFMD*

MGA Zone 56

Easting 554014

Northing 6843206

Summary Statistics




1.61



-1.02



1990-2010

MHW (m) 0.54

MSL (m) 0.05

MLW (m) -0.44


-1.5

-1.0

-0.5

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1 10 100 1000 10000 100000W

ate

r L

ev

el

(m)


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0.0001 0.001 0.01 0.1 1 10 100

Wa

ter

Lev

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(m)


Figure

Report 2100

A19

MHLNSW WATER LEVEL


BRUNSWICK RIVER AT MULLUMBIMBY

Station Information

River/Estuary System Brunswick River

AWRC No. 202402

Station name Mullumbimby

Datum BRFMD*

MGA Zone 56

Easting 548580

Northing 6841766

Summary Statistics




4.54



-0.62



1990-2010

MHW (m) 0.57

MSL (m) 0.10

MLW (m) -0.37

Notes:


analysis table.









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ter

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ve

l (m

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Wa

ter

Lev

el

(m)


Figure

Report 2100


A20

MHL

STATION LOCATIONS

RICHMOND RIVER REGION

0 10km

Scale 1:250 000

Map courtesy of AUSLIG

N

Coraki

Woodburn

Bungawalbin

Tucombil Floodgate

Iron GatesEvans River

Fishing Co-op

Rocky Mouth Creek

Tucombil Highway Bridge

Woodlawn College

Tuncester

East Gundurimba

Lake Ainsworth

Byrnes Point

Wardell

Ballina Breakwall

Figure

Report 2100

A21

MHLNSW WATER LEVEL


LENNOX HEAD AT LAKE AINSWORTH

Notes:

Station temporarily decommissioned

December 2007 to May 2009.

Refer to Appendix B for frequency

distribution analysis table.








Station Information

River/Estuary System Lennox Head

AWRC No. 203455

Station name Lake Ainsworth

Datum AHD*

MGA Zone 56

Easting 557863

Northing 6816160

Summary Statistics




3.18

Date recorded 15/07/199916/07/1999


1.17

N/A

N/A

N/A

N/A

Date recorded 17/12/2002 to23/02/2003


MHW (m)

MSL (m)

MLW (m)


1.0

1.5

2.0

2.5

3.0

1 10 100 1000 10000 100000

Wa

ter

Le

ve

l (m

)


1.0

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3.5

0 20 40 60 80 100

Wa

ter

Documents

OEH NSW WATER LEVEL FREQUENCY DISTRIBUTION ANALYSIS