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HAWKESBURY CITY COUNCIL
LOWER MACDONALD RIVER
FLOOD STUDY
AUGUST 2004
HAWKESBURY CITY COUNCIL
LOWER MACDONALD RIVER FLOOD STUDY
AUGUST 2004
Webb, McKeown & Associates Pty Ltd Prepared by: ___________________________Level 2, 160 Clarence Street, SYDNEY 2000Telephone: (02) 9299 2855Facsimile: (02) 9262 6208 Verified by: ____________________________22032:MacRiverFSFinal.wpd
LOWER MACDONALD RIVER FLOOD STUDY
TABLE OF CONTENTS
PAGE
1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Catchment Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 General Morphology and Flood History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.1 Previous Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.2 Topographic and Hydrographic Information . . . . . . . . . . . . . . . . . . . . . . . . . 42.3 Rainfall Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.4 Streamflow Gauging Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.5 Historical Flood Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. APPROACH ADOPTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4. HYDROLOGIC MODEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94.1 Hydrologic Model Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94.2 Model Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94.3 Calibration and Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.3.1 Key Model Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104.3.2 Historical Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. HYDRAULIC MODEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.1 General Approach and Model Establishment . . . . . . . . . . . . . . . . . . . . . . . . 135.2 Hydraulic Model Calibration and Verification . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2.1 March 1978 Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145.2.2 August 1990 Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6. DESIGN FLOWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166.2 Hydrologic Modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166.3 Flood Frequency Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186.4 Adopted Design Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7. DESIGN FLOOD (HYDRAULIC) MODELLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227.1 Tailwater Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227.2 Design Flood Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7.2.1 Flood Levels, Extents and Flow Distribution . . . . . . . . . . . . . . . . . 237.2.2 Provisional Flood Hazard and Hydraulic Categorisation . . . . . . . . 257.2.3 Provisional Categorisation of Flood Prone Land . . . . . . . . . . . . . . 26
7.3 Comparison of the 100 Year ARI Design Event With the 1949 Flood . . . . . 27
8. CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
9. ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
10. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
LIST OF APPENDICES
APPENDIX A: GLOSSARY OF FLOOD RELATED TERMSAPPENDIX B: PUBLISHED GEOMORPHOLOGICAL ANALYSIS OF MACDONALD RIVER APPENDIX C: PHOTOGRAPHS OF HISTORICAL FLOOD LEVEL SURVEY SITESAPPENDIX D: DESIGN FLOOD RESULTS
LIST OF TABLES
Table 1: Available Rainfall Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Table 2: Available Streamflow Gauging Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Table 3: Recorded Flood Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Table 4: WBNM Model Calibration: Adopted Model Parameters . . . . . . . . . 11Table 5: Historical Storms: WBNM Model Performance . . . . . . . . . . . . . . . . . . . . . . 11Table 6: Modelled Peak Flows (m3/s) at St Albans . . . . . . . . . . . . . . . . . . . . . . . . . . 17Table 7: Sensitivity of Initial Loss Values - 100 Year ARI Peak Flow Estimates . . . . 17Table 8: Sensitivity of Areal Reduction Factors - 100 Year ARI Peak Flow Estimates
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Table 9: Annual Flood Series: Macdonald River at St Albans (Station 212010) . . . . 18Table 10: Flood Frequency Analyses: Macdonald River at St Albans (Station 212010)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Table 11: Design Flood Levels at Wisemans Ferry . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Table 12: Summary of Design Flood Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Table 13: 100 Year ARI Event - Provisional Flood Categorisation . . . 27
LIST OF FIGURES
Figure 1: Study AreaFigure 2: Available Survey DataFigure 3: Available Hydrologic DataFigure 4: WBNM Model LayoutFigure 5: Historical Rainfall Data: March 1978 EventFigure 6: Historical Rainfall Data: August 1990 EventFigure 7: Historical Rainfall Data: April 1988 EventFigure 8: Historical Rainfall Data: August 1986 EventFigure 9: Flow Hydrographs: March 1978 EventFigure 10: Flow Hydrographs: August 1990 EventFigure 11: Flow Hydrographs: April 1988 EventFigure 12: Flow Hydrographs: August 1986 EventFigure 13: MIKE11 Model LayoutFigure 14: Comparison with Available Data: March 1978 Event Peak Flood Height ProfileFigure 15: Stage Hydrographs at St Albans: March 1978 Calibration EventFigure 16: Discharge Hydrographs at St Albans: March 1978 Calibration EventFigure 17: Comparison with Available Data: August 1990 Event Peak Flood Height ProfileFigure 18: Stage Hydrographs at St Albans: August 1990 Verification EventFigure 19: Discharge Hydrographs at St Albans: August 1990 Verification EventFigure 20: Flood Frequency AnalysesFigure 21: Peak Height Profiles: Design Events - Macdonald RiverFigure 22: Design Flood Levels: 500 Year ARI EventFigure 23: Design Flood Levels: 200 Year ARI EventFigure 24: Design Flood Levels and Extents: 100 Year ARI EventFigure 25: Design Flood Levels: 50 Year ARI EventFigure 26: Design Flood Levels and Extents: 20 Year ARI EventFigure 27: Design Flood Levels: 10 Year ARI EventFigure 28: Design Flood Levels: 5 Year ARI EventFigure 29: Design Flood Levels and Extents: Extreme Flood EventFigure 30: Example of Flow Distribution at Model Cross-SectionsFigure 31: Flood Hazard at Cross-Sections: 100 Year ARI Flood EventFigure 32: Flood Hazard at Cross-Sections: Extreme Flood EventFigure 33: Categorisation of Flood Prone LandFigure 34: Comparison of 100 Year ARI Design Event With The 1949 Historical Event: Peak
Height Profile - Macdonald RiverFigure C1: Observed Flood Heights - Longitudinal Profile of Macdonald River
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The State Government’s Flood Policy is directed at providing solutions to existing flooding problems
in developed areas and to ensuring that new development is compatible with the flood hazard and
does not create additional flooding problems in other areas.
Under the Policy, the management of flood liable land remains the responsibility of local
government. The State Government subsidises flood mitigation works to alleviate existing
problems and provides specialist technical advice to assist Councils in the discharge of their
floodplain management responsibilities.
The Policy provides for technical and financial support by the Government through the following
four sequential stages:
1. Flood Study
• determines the nature and extent of the flood problem.
2. Floodplain Risk Management Study
• evaluates management options for the floodplain in respect of both existing and
proposed development.
3. Floodplain Risk Management Plan
• involves formal adoption by Council of a plan of management for the floodplain.
4. Implementation of the Plan
• construction of flood mitigation works to protect existing development,
• use of planning controls to ensure new development is compatible with the flood
hazard.
The Macdonald River Flood Study constitutes the first stage of the management process for this
catchment. This study has been prepared for Hawkesbury City Council by Webb, McKeown &
Associates to define flood behaviour under current conditions.
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This report was prepared by Webb McKeown and Associates on behalf of Hawkesbury City Council
(HCC) and details the engineering investigations carried out to determine the design flood levels,
flows and velocities for the Lower Macdonald River floodplain. It represents the first step in the
process to develop a Floodplain Risk Management Plan for the study area.
The Macdonald River catchment is a tributary of the Hawkesbury River and drains an area of
approximately 1845 km2. Significant flooding has occurred in the past including a severe event in
1949.
All available topographic, rainfall and flood data were collected and analysed as part of the study.
To extend the existing data sets, Council undertook detailed survey to provide cross-section
information and to define the heights of historical flood levels provided by local residents.
A WBNM hydrologic model was established to represent the entire catchment draining to the
Hawkesbury River. A MIKE-11 hydraulic model was created to represent the Lower Macdonald
River downstream of the confluence with Womerah Creek. The lower reaches of Wrights Creek
were also included in the hydraulic model.
The hydrologic and hydraulic models were calibrated making best use of available historical data
to ensure that they reasonably simulated recorded historical floods. The models were calibrated
to the March 1978 flood and verified against the August 1990 event. For both models, parameter
values found to be applicable in previous studies of similar catchments and those from established
texts were used to determine appropriate values for the present study.
In addition, a flood frequency analysis was undertaken on the streamflow estimates obtained from
the gauge located on the Macdonald River at St Albans. The adopted set of design flows were
used to define inflow hydrographs to the hydraulic model. The lower reaches of the Macdonald
River are influenced by a combination of flows entering from the upper catchment in addition to
elevated water levels associated with concurrent flooding in the Hawkesbury River. Design flood
information was therefore obtained using the calibrated hydraulic model in conjunction with a range
of tailwater conditions.
The main outcomes of this study are documented in this report and include:
• a full description of the methodology and results,
• the reporting of design flood information including the preparation of flood information
maps for the Lower Macdonald River catchment,
The information contained herein is suitable for the preparation of a subsequent Floodplain Risk
Management Study and Plan. A glossary of flood related terms is provided in Appendix A.
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1. INTRODUCTION
1.1 Overview
Current flood planning levels used for the Macdonald River floodplain are based on a flood profile
prepared by Council staff in 1984. This profile was defined using a compilation of available flood
level information from past flood events and its relevance to corresponding design flood levels was
not known. In order to properly plan and manage both existing and future development within the
floodplain, there is a need to establish appropriate flood planning levels using a more rigorous, up
to date technical analysis.
In order to provide a solid technical foundation for flood planning levels within the valley, Webb,
McKeown & Associates were engaged by Hawkesbury City Council (HCC) to prepare this Flood
Study. The primary objectives of the study are:
• to define the flood behaviour for the lower reaches of the Macdonald River under existing
conditions,
• to establish numerical hydrologic and hydraulic models to determine flood flows, velocities
and levels for all design events,
• to formulate the models such that the effects on flood behaviour due to catchment
development and possible mitigation measures can be investigated in the future.
This report details the methodology used and the results of the design flood analysis. It includes:
• a summary of available data,
• reasons supporting the choice of hydrologic and hydraulic models,
• calibration and verification of these models,
• definition of design flood behaviour in accordance with the NSW Floodplain Management
Manual (2001).
All levels provided in this report are in metres (m) to Australian Height Datum (AHD) which is the
standard national survey reference plane approximating mean sea level.
1.2 Catchment Description
The Macdonald River is a tributary of the Hawkesbury River and drains a catchment area of
approximately 1845 km2 (Figure 1). The catchment consists of steeply vegetated slopes up to
elevations of around 800 m. The upper portions of the catchment consist predominantly of natural
bushland terrain. Downstream of the Womerah Creek confluence, the Macdonald River floodplain
is constrained by the steep relief of the surrounding hills and is typically between 300-500 m in
width.
The majority of development within the catchment consists of scattered free standing dwellings
located on rural acreages. The density of development increases in the downstream reaches of
the valley. The highest concentration of residential development is located approximately 1-2km
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upstream of the Hawkesbury River junction, along the eastern side of the Macdonald River
floodplain.
1.3 General Morphology and Flood History
Flooding within the valley is primarily a consequence of surface runoff generated in the upper
reaches and from local catchments. The lower reaches of the Macdonald River can also be
affected by backwater effects from the Hawkesbury River during periods of coincident flooding.
Due to the long history of settlement within the Lower Macdonald valley, there is also an established
history of flooding with significant events known to have occurred in 1978, 1964, 1949 and as far
back as 1889. In particular, several successive major floods occurred on the Macdonald River
between 1949 and 1955. The most recent notable flood event on record occurred in August 1990.
The nature and form of the Macdonald River within the immediate study area is known to have
undergone significant changes over the last 150 years. An initial geomorphological analysis of the
Macdonald River floodplain is presented in Reference 1 (for completeness, this reference has been
reproduced in Appendix B). From a combination of available survey information and anecdotal
evidence provided by a range of local land owners, Reference 1 identifies several key changes in
the morphology of the river including:
• Significant changes to the in-channel geometry resulting from the deposition of sand along
a significant length of the river extending from upstream of St Albans (near Marlo Creek)
down to Wrights Creek. Reference 1 presents evidence indicating that the magnitude of
bed aggradation in some areas is as much as three (3) metres.
• Major changes in the shape and form of the overbank/floodplain areas immediately
adjacent to the main river channel. Reference 1 concludes that significant bank erosion
occurred during the major floods which followed the June 1949 event. It is suggested that
the sediment eroded from the immediate banks has contributed in large part to the level
of bed aggradation observed in the lower reaches of the Macdonald River.
• The formation of permanent lagoons in the lower reaches. Several of the low-lying smaller
tributaries were formed into permanent lagoons as a consequence of the bed aggradation
of the main river channel that resulted from the floods of the early 1950's.
Definitive information quantifying the overall changes in the longitudinal profile of the channel bed
over time is not available. However, in response to the aggradation of the channel bed, the
available information indicates that the width of the main river channel has been substantially
widened (as expected). For example, in the reach extending from 2km upstream of the Mogo
Creek junction down through to St Albans, anecdotal evidence suggests that the typical channel
width has increased up to five-fold following the 1949 flood event. The subsequent floods that
occurred between 1952 and 1955 were noted to result in significant bank erosion forming the broad
benched-type of overbank geometry that typifies the present floodplain within the immediate study
area. In the absence of more detailed information, the precise behaviour of the river in the future
is uncertain. For example, the gradual movement of the tidal limit upstream and the deepening of
the channel in the lower reaches of Wrights Creek (noted in Reference 1) provide some evidence
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of bed recovery. However, Reference 1 also notes that the presence of indurated bed conditions
within a cut-off meander of the Macdonald River (located approximately 2kms upstream of Wrights
Creek confluence) is likely to limit the rate of bed recovery for these lower reaches.
Regardless of the precise behaviour of the river in the future, it is clear that the river and floodplain
can be considered to be morphologically active. From a flooding perspective, the aggraded bed
is likely to result in an increase in the occurrence of overbank flooding, although the magnitude of
the corresponding impacts on flood levels experienced during more extreme events will be relatively
lower (as flooding during the larger events occurs across the overall floodplain).
Importantly, for the present study, the presence of underlying changes in river morphology also
makes the precise interpretation of historical flood behaviour difficult to achieve. Within the context
of the present investigation, the level of morphological activity adds an element of uncertainty into
the design flood behaviour ultimately obtained. From a planning perspective, the potential for
ongoing-channel widening and/or significant bank erosion should be also be taken into account (in
addition to flooding considerations) when siting developments within the floodplain. These types
of analyses are further complicated by the sparseness of available historical information.
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2. DATA
2.1 Previous Studies
To date, there have been no formal flood studies which have assessed the design flood behaviour
of the lower Macdonald River floodplain in specific detail. There are several published studies of
the hydrology and hydraulics of the Hawkesbury River which incorporate information concerning
the Macdonald River catchment. However, these studies were primarily focussed on Hawkesbury
River flood behaviour with the Macdonald River catchment considered in a broad context only.
Several studies which have provided some basis for the present detailed investigation include:
• Warragamba Dam Auxiliary Spillway EIS Flood Study (1996 - Reference 2)
Presented as a series of reports, this reference documents the development and use of hydrologic
and hydraulic models for the Hawkesbury-Nepean River system which were undertaken as part of
an EIS for the Warragamba Dam Auxiliary Spillway. The reports provide a detailed analysis of
historical rainfall and flood records across the broader Hawkesbury-Nepean catchment and include
information concerning the hydrologic modelling of the Macdonald River catchment.
• Lower Hawkesbury River Flood Study (1997 - Reference 3)
This study was part of a series of studies undertaken in the formulation of a floodplain management
plan for the Hawkesbury-Nepean valley. The study examines the flooding characteristics of the
Lower Hawkesbury River from Sackville to the ocean. A flood frequency analysis was undertaken
for the streamflow gauge at St Albans and design discharge estimates were derived as part of this
analysis. No specific information on the flood hydraulics for the lower Macdonald floodplain is
presented in the report.
2.2 Topographic and Hydrographic Information
1:100000 scale and 1:25000 scale topographic maps were used to provide an overview of the
broader topographic features of the catchment. The 1:100000 map series of the area was also
used to delineate the sub-areas for the hydrologic modelling (discussed later in Section 4).
Prior to commencement of the current study, the available cross-section information was limited
to a hydrographic survey below the tidal limit of the lower Macdonald River. This survey was
undertaken in the early 1980's by the then NSW Department of Public Works (PWD). This data
has been used in subsequent hydraulic modelling investigations for the Hawkesbury River
(References 2 and 3).
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As part of the present study, additional surveys were commissioned to:
• extend the hydrographic survey upstream of the tidal limit, and
• provide overbank detail to correspond with the channel sections obtained from the
hydrosurvey.
The locations of the new cross-sections were determined based on a field inspection conducted by
Webb McKeown in conjunction with Council staff. Consideration was also given to the locations
of the existing hydrosurvey. The additional survey information was obtained by Council using
GPS-based techniques. The new survey information is estimated to have an order of accuracy of
±0.05 m in general although there may be localised errors of up to ±0.25 m in some locations.
The locations of all available survey information used in the study are shown in Figure 2.
2.3 Rainfall Data
There are a number of daily-read rainfall gauges and pluviometers located within or in close
proximity to the Macdonald River catchment. The quality of data describing recorded actual rainfall
patterns has improved following the installation of several pluviometers within the catchment by
Sydney Water in June 1990. Prior to this, the description of the rainfall temporal patterns for
historical events relied on records collected outside of the catchment. An exception to this was a
pluviometer at Eraring which was operated for an unknown period by the then Electricity
Commission of NSW from around 1977. These records were sought during the initial phases of
the present Study. Unfortunately, as a result of the restructuring within the power utility sector, the
data records for this station could not be sourced. Details of the available rainfall stations in the
immediate vicinity of the catchment are provided in Table 1 and the corresponding locations are
shown in Figure 3.
Table 1: Available Rainfall Stations
Number Name Source Coverage Type061296 Howes Valley (Owensdale) BoM 1970 - Present Daily061119 Wisemans Ferry (Old Post Office) BoM 1903 - Present Daily061284 Lambton BoM 1870 - 1920 Daily061030 Howes Valley (Kindarun) BoM 1914 - 1975 Daily061217 St Albans BoM 1963 - Present Daily061211 St Albans (Mogo Creek) BoM 1963 - Present Daily067044 Lower Portland BoM 1963 - 1992 Daily061209 Putty Post Office (Putty Composite) BoM 1977 - Present Daily, Pluvio.061217 Colo Heights Composite BoM 1962 - Present Daily, Pluvio.061336 Putty (The Gibba) BoM 1975 - Present Daily, Pluvio.061351 Peats Ridge (Waratah Rd) BoM 1981 - Present Daily, Pluvio.561103 Howes Valley (Noisy Point) AWT 1990 - Present Pluviograph561102 Putty Forest (3 Ways) AWT 1990 - Present Pluviograph561107 Mt Calore AWT 1990 - Present Pluviograph561106 Bala AWT 1990 - Present Pluviograph561108 Womerah AWT 1990 - Present Pluviograph561101 Mangrove Mtn (Dubbo Gully) AWT 1990 - Present Pluviograph
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2.4 Streamflow Gauging Stations
Streamflow gauging stations on the Macdonald River are located at St Albans and Howes Valley
(Table 2). Both stations were originally established by the NSW Department of Water Resources
but are now operated and maintained by Department of Infrastructure, Planning and Natural
Resources (DIPNR). Continuous water level recordings commenced in 1972 at St Albans and in
1976 at Howes Valley. At both sites the control is based on a sandy bed and no high flow gauging
has been undertaken. Hence, a degree of caution is needed when interpreting the observed flow
records, particularly for smaller events. For the St Albans gauge, the data record is intermittent with
significant portions of missing data.
Table 2: Available Streamflow Gauging Stations
Number Name Catchment
Area (km2)
Years of Record Maximum Gauging
(m above Gauge Zero)
212010 St Albans 1680 1954 - Present 2.99 m on 05/03/1976*
212021 Howes Valley 299 1972 - Present 2.88 m on 20/03/1978
* Estimate of Gauge Zero at St Albans is 2.86 mAHD (HCC Council Survey, 2003).
2.5 Historical Flood Levels
A number of flood level records exist for different sites throughout the Lower Macdonald River
floodplain. For the present study, historical information was obtained from a number of sources
including Council records and existing hydrologic and technical reports related to the area.
In addition, local residents were canvassed during the initial stages of the present study for
information relating to past floods. Where possible, this information was used to provide flood
height estimates, the levels of which were surveyed during the compilation of overbank
cross-section data. A summary of available information is presented in Table 3.
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Table 3: Recorded Flood Levels
Event Location Chainage from
Hawkesbury River (m)
Level
(mAHD)
Source(see footnote)
Council Point
Reference No.
1896 Wrights Ck
Junction
13890 9.3 Council Profile
1984
-
1949 29440 15.83 Council
Survey 2003
108
1949 28110 14.99 Council
Survey 2003
503
1949 27140 14.2 Council
Survey 2003
526
1949 ~200m U/S of
St Albans
22185 15.1 Council
Survey 2004
1000
1949 St Albans 22185 14.3 Council
Survey 2003
549
1949 St Albans 22185 14.65 Council Profile
1984
-
1949 Wrights Ck
Junction
13890 8.8 Council Profile
1984
-
1949 Wrights Ck
Junction
13890 10.6 Council
Survey 2003
441
Mar 1978 29440 14.64 Council
Survey 2003
105
Mar 1978 27140 13.2 Council
Survey 2003
525
Mar 1978 16570 10.6 Council
Survey 2003
151
Mar 1978 St Albans 22185 11.25 Council Profile
1984
-
Mar 1978 Wrights Ck
Junction
13890 7.65 Council Profile
1984
-
Mar 1978 1910 4.9 Council Profile
1984
-
Aug 1990 St Albans 22185 8.75 Sydney
Catchment
Auth.
-
NOTE: ‘Council Profile 1984' refers to a Flood Profile plan established by Council in 1984.
A photographic summary of the locations of the observed flood heights obtained by Council for this
study is provided in Appendix C. It is recommended that Council pursue the collection of this type
of flood-related information following future flood events.
A detailed discussion concerning the available historical flood information is provided in Section 5.2.
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CATCHMENT INFORMATIONsub-areasland-use
percentage Imperviousstorage basin data
observed runoff volumes or rates
RAINFALL DATAhistorical or design storm events
rainfall depths (Isohyets)temporal patterns (intensity v
time)
MODEL BOUNDARY CONDITIONSdownstream ocean/tide levelsupstream inflow hydrographsdirect rainfall - lateral inflows
CALIBRATION/VERIFICATIONComputational Modelling Software
HYDROLOGIC ANALYSIS
QUANTIFY CATCHMENT RUNOFFestimated flow hydrographs
HYDRAULIC CHARACTERISTICS
topographic databridge/culvert details
overflow weir structuresdefine flow paths
stream roughness values
OBSERVED FLOOD BEHAVIOURpeak heights
stage or flow hydrographsrelative timing of events
velocity estimatesgeneral observations
COMPUTER MODEL PARAMETERSstorage-routing coefficient
rainfall losses
CALIBRATION/VERIFICATIONComputational Modelling
Software
QUANTIFY FLOOD BEHAVIOURflood levels
flowsvelocities
HYDRAULIC ANALYSIS
REVIEW
3. APPROACH ADOPTED
Initially, a hydrologic model (WBNM) was established for the entire catchment and used to convert
rainfall data into streamflow for input to a hydraulic model of the lower Macdonald floodplain. To
ensure confidence in the results produced, both the hydrologic and hydraulic models require
calibration and verification against observed historical events. The hydrologic model was calibrated
to the available streamflow data for the St Albans gauge. The hydraulic model was then calibrated
to the available streamflow and peak flood level data where possible. Using the calibrated models,
the design flood behaviour was then quantified for a range of design storm events up to and
including an extreme event approximating the PMF. A representation of the Flood Study process
is shown in Diagram 1.
Diagram 1: Flood Study Process
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4. HYDROLOGIC MODEL
4.1 Hydrologic Model Description
Hydrologic models suitable for design flood estimation are described in AR&R87 (Reference 4).
In current Australian engineering practice, examples of the more commonly used runoff routing
models are RORB, RAFTS and the Watershed Bounded Network Model (WBNM). These models
allow the rainfall depth to vary both spatially and temporally over the catchment and readily lend
themselves to calibration against recorded data. Details of these models are discussed in
Reference 4.
The MacDonald River catchment has been previously modelled using RORB (Reference 2). The
existing RORB model was established to provide design discharges for a much larger study which
assessed runoff behaviour for the overall Hawkesbury-Nepean catchment. The Macdonald River
catchment was only a small sub-catchment and consequently was only defined using a limited
number of sub-areas. Both RORB and WBNM offer similar features. However, WBNM is easier
to use and requires less data. It also has the advantage over RORB of using different approaches
to modelling overland runoff and streamflow. For these reasons and in order to provide a greater
level of detail, a WBNM model was established for the present study.
4.2 Model Configuration
The WBNM model simulates a catchment and its tributaries as a series of sub-catchment areas
based on watershed boundaries linked together to replicate rainfall/runoff process through the
natural stream network. The adopted sub-catchment division is shown on Figure 4. The model input
data includes definition of physical characteristics such as:
• surface area,
• proportion developed (imperviousness),
• stream shortening.
The model established for this study comprised a total of 35 sub-areas and included all tributaries
upstream of the Macdonald River confluence with the Hawkesbury River. The layout of the
sub-areas was defined to provide a reasonable level of spatial detail within the catchment and to
provide flow hydrographs at specific locations. For example, the model was structured to provide
primary inflows at the upstream limits of the hydraulic model as wells as hydrographs corresponding
to streamflow gauging sites to assist with model calibration and verification. Catchment areas for
each sub-area were determined from the 1:100000 series topographic maps. As a check, the total
catchment area draining to St Albans in the WBNM model was found to be within 3% of the
catchment area quoted for the gauging station at St Albans. The original WBNM areas were then
slightly adjusted (as a whole) to match the catchment area reported for the St Albans gauge. Given
the scale of the hydrologic modelling and the limited nature of development within the overall
catchment, no impervious areas were defined in the WBNM model.
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4.3 Calibration and Verification
4.3.1 Key Model Parameters
In calibrating the WBNM model, several parameters can be varied to achieve a fit to observed data:
• Non-Linearity Exponent of the Storage Routing Equation
This is an internal variable which modifies the storage routing functions in the model. For
the present study, it was set at the recommended value (0.77).
• Rainfall Losses
Two parameters, initial loss (IL) and continuing loss (CL), modify the amount of rainfall
excess to be routed through the model storages.
• Lag Parameter
The Lag Parameter affects the timing of the catchment response to the runoff process and
is subject to catchment size, shape and slope.
The WBNM model was calibrated by adjusting these parameters in order to match the recorded
streamflow hydrographs available for a given event(s). The performance of the calibrated model
is then verified by comparison with an independent historical flood event(s).
4.3.2 Historical Events
The value of a particular flood for calibration of the hydrologic model largely depends on the
following:
• quantity and quality of daily rainfall data,
• quantity and quality of pluviograph data and the proximity of the gauges to the catchment,
• magnitude of the flood event.
Taking these factors into account, the calibration of the WBNM model was principally based on the
March 1978 flood event, this being the largest flood event having sufficient rainfall and streamflow
data suitable for calibration. Verification was provided by the August 1990 flood, whilst the smaller
floods in August 1986 and April 1988 were used as additional confirmation of model performance.
For each historical event, rainfall depths and temporal patterns were assigned based on the
available rainfall totals, isohyetal maps and pluviograph records (refer Figures 5 to 8).
An assessment of the likely baseflow component for each of the estimated hydrographs at
St Albans was made for all of the above historical events using the techniques outlined in
Section 8.3 of AR&R87 (Reference 4). For the March 1978, significant gaps in the data record
during the recession limb prevented a reasonable estimation of baseflow component. However,
analysis of the remaining three events showed that the baseflow portion of the overall hydrograph
volume was small and unlikely to affect the flood behaviour of the catchment in the context of the
present study. In view of this, no separation of baseflow was made from the historical flow
hydrographs used to calibrate the WBNM model at St Albans.
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The adopted model parameters are shown in Table 4. A comparison of the results produced by
the WBNM model with the observed streamflow data for each historical event is provided in Table 5
and in Figures 9 to 12.
The outcomes of the model calibration and verification are discussed further in Section 4.4.
Table 4: WBNM Model Calibration: Adopted Model Parameters
Storm Non-linearity
Exponent of
Storage
IL
(mm)
CL
(mm/h)
Lag
Parameter
Mar 1978 0.77 70 3.0 1.90
Aug 1990 0.77 37 1.0 1.90
Aug 1986 0.77 85 6.5 1.90
Apr 1988 0.77 50 1.0 1.90
Table 5: Historical Storms: WBNM Model Performance
Storm Observed
Peak
Discharge
(m3/s)
Modelled
Peak
Discharge
(m3/s)
Relative
Difference
(%)
Observed
Volume
(m3 x 106)
Modelled
Volume
(m3 x 106)
Relative
Difference
(%)
Mar 1978 880 920 5% 129 133 3%
Aug 1990 500 510 2% 97 79 -19%
Aug 1986 100 120 20% 17 15 -12%
Apr 1988 130 130 0% 20 16 -20%
4.4 Discussion
The results of the WBNM calibration for the March 1978 event (refer Table 5 and Figure 9) indicate
that the WBNM model matches both the peak discharge and the runoff volume reasonably well.
However in comparison to the modelled hydrograph at St Albans, the shape of the rising limb of the
observed hydrograph shows a greater degree of variation, having a distinct ‘kink’ between 55 and
60 hours following the start of the rainfall event (Figure 9). The inability of the predicted hydrograph
to reproduce this behaviour is attributed to uncertainties in the rainfall temporal patterns adopted
for this event. As noted previously (Section 2.3), there were no pluviograph records within the
Macdonald River catchment available for the March 1978 event. Given these limitations the WBNM
model calibration is considered satisfactory.
In view of the available rainfall and streamflow data, the more recent August 1990 event was
considered the most appropriate to verify the performance of the calibrated WBNM model. Unlike
the March 1978 event, there were several pluviographs operating within the study catchment during
the August 1990 event. The results obtained (refer Figure 10 and Table 5) indicate that the model
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reproduced the peak discharge and the general shape of the observed hydrograph at St Albans
well. This is attributed to the availability of recorded pluviograph data at several locations within the
catchment. However, it is noted that the model under-predicts the observed runoff volume by up
to 20%. Although a range of continuing loss rates were tested to improve the model results, a
continuing rainfall loss of 1.0 mm/hour was ultimately adopted. Given the nature of the catchment,
it was considered that the use of a continuing loss rate less than 1.0 mm/hour would be unrealistic.
Any errors in the model results were therefore attributed to uncertainties in the rainfall totals
assigned to the various sub-areas for this event. In the absence of additional data which might
better describe the spatial variation of rainfall across the catchment in more detail, the verification
of the WBNM for the August 1990 event was considered reasonable.
Although they are significantly smaller than either the March 1978 or August 1990 events, the April
1988 and August 1986 flood events were also simulated in WBNM to provide some confirmation
(re-assurance) of the overall model performance for both large and small events.
Figure 11 shows the results for the April 1988 event. Although the WBNM model matches the peak
discharge well, the timing of the simulated hydrograph is distinctly different. However, it should be
noted that again there were no pluviograph records available within the catchment. Hence, it is
therefore likely that there may be errors in the assigned temporal pattern for this event. Translation
of the modelled hydrograph indicated that main source of discrepancy in runoff volume is
associated with the recession portion of the hydrograph.
In order to provide a reasonable fit for the August 1986 event, the adoption of a significant
continuing loss (6.5 mm/hr) was required. This would seem to reflect clear deficiencies in the
definition of the historical rainfall pattern for this event (Figure 12). The double peak of the
observed hydrograph further highlights these deficiencies. As per the April 1988 event, there was
limited temporal information available for this event.
Overall, it is considered that the calibration and verification results indicate that the model is
simulating the rainfall/ runoff process reasonably well. The timing and overall fit of the larger flood
events, used for calibration and verification, are considered to be good. While the model nominally
appears to underestimate the runoff volume of observed events, it is still considered to be suitable
for estimating flows for design storms. Design storms have a single temporal pattern and relatively
uniform spatial pattern and are therefore not as susceptible to the variable nature (peaky) of flows
generated from observed storm events.
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5. HYDRAULIC MODEL
5.1 General Approach and Model Establishment
Given the objectives of the study, the nature of the flowpaths and watercourses within the Lower
Macdonald valley and the available data, a one-dimensional (1D) flow representation provides the
most efficient and effective representation of flood behaviour. This is particularly so as the
floodplain is bounded by steep terrain and is therefore relatively confined throughout the study
reach.
A 1D hydraulic model was established using the MIKE11 software package (Reference 5). The
MIKE11 model is widely used in flood engineering both within Australia and internationally. It is a
proven tool for the dynamic modelling of branched networks with complex cross-sections and
hydraulic control structures.
The MIKE11 model layout of the Macdonald River extends from just upstream of the Womerah
Creek junction down to the confluence with the Hawkesbury River at Wisemans Ferry (Figure 13).
The lower reach of Wrights Creek was also included as part of the model. The model
cross-sections were derived from the GPS survey data (discussed previously in Section 2.2).
Where possible, the in-channel definition of each section was supplemented by the available
hydrosurvey data of the Macdonald River (surveyed in 1984 by the then NSW Public Works
Department).
The locations of the river crossings in the immediate study area were identified from available
mapping information and verified during an initial site inspection. The details of several smaller
low-lying crossings were obtained as part of the ground survey component of the study. For the
bridge crossing of the Macdonald River at St Albans, detailed plans were obtained from the Roads
and Traffic Authority (RTA). Detailed modelling of the St Albans bridge indicated that only minor
headlosses less than 5cm (0.05m) would occur at this location due to the support piers.
5.2 Hydraulic Model Calibration and Verification
The hydraulic efficiency of the river is represented (in part) in the MIKE11 model by the stream
roughness or friction factor formulated as Manning’s ‘n’. This factor describes the net influence of:
• channel roughness
• channel sinuosity
• vegetation and other debris within the channel/overbank.
• bed forms and shape.
Consistent with the quality and reliability of historical flood data, the March 1978 event was used
for the calibration of the MIKE11 model. The Manning’s ‘n’ values used in the model were adjusted
within reasonable vicinity to best reproduce the observed flood behaviour for this event. A limited
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form of model verification was then provided through a comparison of the model results with the
recorded stage hydrograph at St Albans for the August 1990 event.
For each event, the boundary conditions for the MIKE11 model consist of a series of time-varying
inflow hydrographs obtained from the calibrated WBNM model and observed stage hydrographs
for the downstream model boundary at Wisemans Ferry (Reference 3).
5.2.1 March 1978 Event
Following a series of trial runs, it was found that the following set of Manning’s ‘n’ values best
reproduced the observed flood behaviour for the March 1978 event:
• n=0.037: defined for the Macdonald River reach between Womerah Creek to approximately
4.5km downstream of St Albans
• n=0.041: defined for the remaining lower reaches of the Macdonald River including Wrights
Creek.
The two values are reasonably similar in magnitude and were applied uniformly across the model
cross-sections. Based upon site inspections, comparison with published values and values used
in past studies of similar catchments, the values above are considered to be representative of the
surface roughness expected across the entire floodplain. The model results in terms of peak flood
height profiles and time varying hydrographs at St Albans for the March 1978 event are presented
in Figures 14 to 16.
A comparison of modelled and predicted heights along the Macdonald River branch is presented
in Figure 14. The results generally indicate a good agreement between modelled and observed
flood heights. Localised exceptions are noted to occur at several locations:
• For those locations upstream of St Albans, it was found that the hydraulic model
underestimated the observed levels, producing a flatter flood gradient for the March 1978 event.
A detailed review of the historical flood information suggests that the observed levels are fairly
reliable. However, it was found that physically unrealistic roughness factors were needed to be
specified in the hydraulic model to reproduce the flood levels in these locations. The application
of these types of bed roughness values resulted in the water levels at St Albans being
significantly over-estimated. Reasons for the discrepancies in the uppermost reaches could
include event-based morphological changes, localised topographic features present during the
1978 event and limitations in the representation of the river system due to the available cross-
section data. These factors have the potential to introduce a notable degree of uncertainty to
the analysis. Hence, given the reliability of the record at St Albans, the adjustment of the bed
roughness for the upper most reaches to match the observed levels was not undertaken and
the model calibration shown was adopted for design flood modelling. The implications of the
model estimates in this reach are discussed further in the context of design flood level
estimates in Section 7.3.
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• There is a single flood observation of around 10.6 mAHD for the 1978 event located
approximately 1km upstream of the Wrights Creek junction (Figure 14). In comparison, the
MIKE11 model estimates a corresponding flood peak of 8.1 mAHD. Given the match between
the model and observed levels at Wrights Creek and further downstream, the simulated peak
profile through this reach is considered reasonable. Further, a review of surveyed sections and
overall floodplain topography does not overtly indicate the presence of underlying morphological
factors that may have contributed to the higher observed level. For these reasons, the adopted
model calibration in this area was considered sufficient.
From the time-series comparisons presented in Figures 15 and 16, it is evident that the MIKE11
model reproduces both the peak and the timing of the observed flood behaviour reasonably well
at St Albans. Apart from some attenuation (due to an improved representation of channel routing),
the simulated discharge hydrograph directly reflects the corresponding hydrograph estimated by
the WBNM model (as expected). The discrepancies between the MIKE11 and observed
hydrographs can therefore be attributed in large part to the shortcomings in the ability of the WBNM
model to more accurately represent the observed flow behaviour for this event. The discrepancies
preceding the main storm burst reflect the start of the rainfall burst used in the WBNM model and
are not representative of the performance of the MIKE11 model.
Based on the results discussed above, the MIKE11 model is considered to be reasonably well
calibrated within the limitations of the available data and potential uncertainties.
5.2.2 August 1990 Event
As a limited form of model verification, the MIKE11 results were compared to the recorded water
levels and estimated discharges at St Albans (Figures 17 and 19). As per the March 1978 event,
discrepancies between the observed and simulated hydrograph shapes are a consequence of the
hydrological modelling. The MIKE11 model matches the peak flood level reasonably well. The
good agreement shown for the August 1990 event indicates that the calibrated set of models are
performing reliably and are suitable for the estimation of design flood behaviour.
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6. DESIGN FLOWS
6.1 Overview
There are two basic approaches to determining design flood discharges:
• flood frequency analysis - based upon a statistical analysis of the flood record, and
• rainfall/runoff routing - design rainfalls are processed by a suite of computer models to produce
estimates of design flood behaviour.
The approach adopted for this study reflects current engineering practice and has been based on
the quality and quantity of available data. The flood frequency approach requires a reasonably
complete homogeneous record of flows over a number of decades to give satisfactory results.
There are some 30 years of streamflow estimates available for the St Albans gauging station
(Station 212010). Although the length of record is relatively short (<50 years), a flood frequency
analysis was undertaken to provide design discharge estimates to compare against the
corresponding estimates derived from rainfall/runoff routing.
6.2 Hydrologic Modelling
The calibrated WBNM model was used to derive design flows for input to the MIKE11 hydraulic
model. Flow hydrographs were obtained for the 500 Year, 200 Year, 100 Year, 50 Year, 20 Year,
10 Year, 5 Year ARI flood events and an Extreme event.
For each event (up to and including the 500 year ARI event), spatial and temporal design rainfall
patterns were obtained from AR&R for durations ranging from 12 hours to 72 hours. The spatial
pattern was based on that derived for the 36 hour duration 100 year ARI event for the Macdonald
catchment (Reference 2). In all cases, an areal reduction factor of 0.92 was adopted (following
extrapolation from information provided in AR&R). An initial loss of 70 mm/hr was adopted for all
design events. This value was consistent with previous studies (e.g References 2 and 3) and
reflect recommended values provided in AR&R 1987 (Reference 4) and more recent information
detailed in Walsh et.al. (Reference 6). A continuing loss of 2.5mm per hour was used for all design
events up to and including the 500 Year ARI storm. For the extreme event, a continuing loss of
1mm per hour was adopted.
Using the WBNM model, design discharge hydrographs were obtained for storm durations ranging
from 12 hours up to 72 hours. For the lower reaches of the catchment (i.e. downstream of
St Albans), the results showed that the critical duration was consistently between 36 hours to
48 hours, regardless of the magnitude of the design event (Table 6). Given that the 48 hour storm
duration produced slightly larger peaks, the 48 hour duration was adopted as the design storm
duration for the hydraulic modelling.
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Table 6: Modelled Peak Flows (m3/s) at St Albans
Storm Duration (hours)
Frequency (ARI) 12 24 36 48 72
5 Year 225 380 630 720 500
10 Year 410 690 1040 1145 700
20 Year 710 1160 1650 1715 1065
50 Year 1190 1860 2440 2470 1710
100 Year 1600 2450 3140 3200 2260
200 Year 2040 3085 3890 3995 2830
500 Year 2685 3995 4960 5120 3640
Note: Model results obtained using an initial loss of 70 mm, an Areal Reduction Factor of 0.92 and a
Continuing Loss Rate of 2.5 mm/hr.
To assess the impact of key parameters on the modelled 100 Year ARI event, a range of sensitivity
analyses were undertaken. Specifically, these analyses examined the impacts of varying the initial
loss and areal reduction factor for both 36 hour and 48 hour duration storm events. The findings
are summarised in Tables 6 and 7.
Table 7: Sensitivity of Initial Loss Values - 100 Year ARI Peak Flow Estimates
40mm IL
Rel. Diff.(40mm IL
vs. 70mm IL)
70mm IL(adopted)
Rel. Diff.(100mm IL
vs. 70mm IL)
100mm IL
36 Hour Storm Qpeak:3660m3/s 17% Qpeak: 3140m3/s 15% Qpeak: 2490m3/s
48 Hour Storm Qpeak: 3675m3/s 15% Qpeak: 3200m3/s 18% Qpeak: 2640m3/s
Table 8: Sensitivity of Areal Reduction Factors - 100 Year ARI Peak Flow Estimates
ARF=0.76
Rel. Diff.
(0.76 vs.
0.92)
ARF=0.85
Rel. Diff.
(0.85 vs.
0.92)
ARF=0.92
(adopted)
36 Hour Storm Qpeak: 2100m3/s 33% Qpeak: 2675m3/s 15% Qpeak: 3140m3/s
48 Hour Storm Qpeak: 2140m3/s 33% Qpeak: 2730m3/s 15% Qpeak: 3200m3/s
Table 7 shows that the impact of different loss values upon the simulated peak discharge was
relatively minor. Compared to the adopted value of 70 mm, variations in the initial loss resulted in
changes to the predicted peak discharges of not more than 15%. This outcome is to be expected
given the relatively long critical duration for the catchment.
Not surprisingly, there is a notable impact on predicted peak discharges and overall hydrograph
volume due to variations in the Areal Reduction Factor (ARF). Given the objectives of this study,
the size of the catchment and the duration of the storm events, the adopted value of 0.92 was
considered appropriate. In comparison to lower values, the adopted value provides a conservative
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estimate that is consistent with current AR&R recommendations regarding ARF values. More
detailed depth-area-duration analyses were considered to be outside the scope of the present
study.
6.3 Flood Frequency Analysis
Using the available data for the gauging station at St Albans (Station 212010), an annual flood
series was determined (Table 9). Data was sourced from both database records (Pinnenna V6),
the Sydney Catchment Authority and from original gauge cards supplied by DIPNR.
Table 9: Annual Flood Series: Macdonald River at St Albans (Station 212010)
Year Peak Discharge (m3/s) Year Peak Discharge (m3/s)
1955 600 1973 190
1956 No Record 1974 440
1957 No Record 1975 150
1958 240 1976 270
1959 90 1977 660
1960 40 1978 890
1961 60 1979 70
1962 300 1980 5
1963 600 1981 300
1964 740 1982 120
1965 30 1983 30
1966 20 1984 210
1967 350 1985 150
1968 90 1986 100
1969 120 1987 50
1970 20 1988 390
1971 190 1989 510
1972 40 1990 540
In accordance with AR&R 1987 (Reference 4), the annual series was used to derive a Log Pearson
Type III distribution for flood frequency estimates. The resulting fit is plotted together with the
original data and 90-th percentile confidence limits in Figure 20. The estimated design discharges
are presented in Table 10. For comparison, the corresponding design discharge estimates
obtained from the rainfall-runoff modelling (Section 6.2) are also included in Table 10.
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Table 10: Flood Frequency Analyses: Macdonald River at St Albans (Station 212010)
Frequency
(AEP)
Original Annual Series
Discharge (m3/s)
Revised Annual Series (incl.
1949 event) Discharge (m3/s)
WBNM Modelling
Discharge (m3/s)*
20% 430 485 665
10% 620 860 1108
5% 800 1365 1690
2% 1005 2275 2470
1% 1140 3175 3200
0.5% 1260 4290 3990
0.2% 1390 6150 5120
* Note: Discharges for 48 hour duration storm, estimates adjusted to account for annual series comparison.
Prior to the commencement of streamflow gauging at St Albans, there is evidence of several
significant floods occurring on the Macdonald River including events in 1889, 1913 and between
1949 through to 1955. Of these events, a number of flood level records exist for different locations
for the 1949 event, whilst there is only a single reported level for the 1896 event (refer to Table 3).
In order to extend the period across which the flood frequency analysis was undertaken, the peak
flood levels for the 1949 event at St Albans were included to derive an estimate of the
corresponding peak discharge.
For the 1949 event, a number of levels have been recorded in St Albans, including a level of
14.6 mAHD at St Albans bridge and 14.3 mAHD at the Settlers Arms Inn (Table 3). It should be
noted that the reliability of the flood level quoted for St Albans bridge is not known. Attempts to
obtain evidence of the original survey records proved unsuccessful. The results from the MIKE11
model were used to extend the stage-discharge relationship at St Albans to incorporate both these
levels, the corresponding discharges were estimated to range from 2950 m3/s up to 3180 m3/s.
These flows have been estimated assuming that there are no significant tailwater impacts due to
concurrent flooding on the Hawkesbury River. As a conservative estimate, the higher flow of
3180 m3/s was adopted for use in a revised flood frequency analysis that incorporated the 1949
event.
The revised analysis was undertaken using the Bayesian flood frequency inference techniques
provided by the FLIKE flood frequency software package (Reference 7). Using this approach, the
1949 event was incorporated into the analysis essentially as the largest flood to have occurred
between 1913 and 1949 (the 1913 event being the next earliest date of known significant flooding -
the relative size if the 1913 event compared to the 1949 event is not known). The outcome of the
revised flood frequency analysis incorporating the 1949 event is shown in Table 10 and Figure 20.
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6.4 Adopted Design Flows
The comparison of discharges in Table 10 indicates that there is a significant degree of variation
in the design flow estimates obtained from the different methods. The results indicate that the fitted
frequency distribution is sensitive to the addition of the 1949 event. For example, the 100 year ARI
design estimate increased by 80% after the 1949 event was included as part of the annual series.
This degree of sensitivity is directly attributable to the relatively short length of record used in the
analysis. It is therefore suggested that the estimates obtained from the flood frequency analysis
of gauged records are only valid for AEP’s of 30% or greater (based on recommendations
presented in Section 12.6 of AR&R 1987 (Reference 4).
The estimate of the 1% AEP discharge, for the revised analysis, is however comparable to that
obtained from the WBNM model. For more extreme events, the revised frequency analysis
estimates are slightly higher (typically by between 8% and 20%) than the WBNM estimates. In
contrast, Table 10 shows that for more frequent events (such as the 20% or 5% AEP flood) the
design flow estimates obtained from the WBNM model were considerably higher than those
obtained via flood frequency analyses. This trend may be attributable to the fact that the WBNM
estimates are derived from a partial series (Walsh, pers. Comm. 2004). The hydrologic modelling
undertaken using the WBNM model has adopted a constant initial loss value, regardless of the
frequency of the particular event. However, in other studies comparing design estimates from
hydrologic models with those obtained from partial-series based flood frequency analyses, it has
been shown that higher initial losses were needed in the hydrologic model to match the flood
frequency estimates for the more frequent events (Reference 6).
The discrepancy for more frequent events may also be a consequence of the information used to
derive the design rainfall information for AR&R 1987 (Reference 4). As part of the broader
Hawkesbury-Nepean study conducted for Sydney Water in the mid-1990's, the Bureau of
Meteorology were commissioned to undertake a study of information from twenty long term rainfall
gauges (Reference 2). The Bureau's analysis indicated that the rainfall depths recorded at
Wisemans Ferry were up to 20% lower in comparison to those recorded at surrounding rainfall
stations (including the rainfall gauge at Maroota). Advice from the Bureau suggested that this
rainfall shadowing effect at Wisemans Ferry was not incorporated into the information used to
derive the design rainfall data for AR&R. For the Macdonald catchment, this effect would act to
reduce the spatial rainfall gradient down through the catchment, thereby reducing the design rainfall
in the lower part of the catchment. This effect may account for the higher design estimates
produced by the WBNM model for smaller events.
In comparison to previous studies, the WBNM estimates shown in Table 10 are consistent with
design discharges derived from RORB modelling of the catchment undertaken for Sydney Water
(Reference 2). In contrast, the design flows adopted for Macdonald River for hydraulic modelling
of the Lower Hawkesbury (Reference 3) are considerably lower than those obtained for the present
study. For example, in the 100 Year ARI event, the Lower Hawkesbury Flood Study (Reference 3)
adopted a peak discharge of 1,600 m3/s which compares to 3940 m3/s obtained from WBNM
modelling. However, this was using a much lower ARF (0.76) than the present study. Using these
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August 2004 21
lower values in the WBNM model produces a corresponding discharge of around 2300 m3/s for the
48 hour duration event. Additionally, it should be noted that only 50% of the design rainfall was
available as rainfall excess. In view of this and in line with the objectives of this study, the decision
to adopt an ARF of 0.92 was considered more appropriate.
Given the relatively good agreement between the WBNM results and the revised flood frequency
analysis (incorporating the 1949 event), the design discharge hydrographs provided by the WBNM
model were used as inflow boundary conditions for the hydraulic modelling to define design flood
levels throughout the floodplain. Due to the large size of the catchment area, an estimation of a
PMF using standard BoM techniques could not be undertaken. As an approximation, the design
flow hydrographs for an “Extreme event” were estimated as being three times the corresponding
flows for the 100 Year ARI event.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August 2004 22
7. DESIGN FLOOD (HYDRAULIC) MODELLING
7.1 Tailwater Conditions
In addition to runoff from the catchment, the lower reaches of the Macdonald River floodplain can
also be influenced by backwater effects resulting from concurrent flooding of the Hawkesbury River.
The Macdonald River catchment is much smaller in size, compared to the total area draining to the
Hawkesbury River at Wisemans Ferry. Hence, for a given flood event, it is more likely that the flood
levels in the upper part of the floodplain would peak prior to the corresponding flood peak occurs
in the Hawkesbury River. Consideration must therefore be given to accounting for the joint
probability of coincident flooding from both catchment runoff and backwater effects from the
Hawkesbury River.
A full joint probability analysis is beyond the scope of the present study. Traditionally, it is common
practice to estimate design flood levels in these situations using a ‘peak envelope’ approach that
adopts the highest of the predicted levels from the two mechanisms. This is the approach that has
been adopted for this study. For events up to and including the 20 Year ARI event, a constant level
of 1.5 mAHD was used at the downstream boundary of the MIKE11 model to derive the design
flood levels for the upper reaches of the Macdonald River Floodplain. This tailwater level
corresponds (nominally) to the 100 year design ocean level at Broken Bay. Similarly, a peak
tailwater level of 4.4 mAHD (corresponding to the 20 Year ARI design flood level at Wisemans
Ferry) has been adopted for the 100 Year, 200 Year and 500 Year ARI events. For each of these
runs, the peak flood level for the lower reaches has been defined as the peak level estimate from
the MIKE11 model or the corresponding design level at Wisemans Ferry (Table 11), whichever is
the higher.
Table 11: Design Flood Levels at Wisemans Ferry
Event Level (mAHD)
at Wisemans FerryExtreme 16.3
500 Year ARI 9.5 *
200 Year ARI 8.0 *
100 Year ARI 6.7
50 Year ARI 5.6
20 Year ARI 4.4
10 Year ARI 3.9 *
5 Year ARI 3.2
Notes: * Interpolated for the purposes of this study.Source: Reference 3
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7.2 Design Flood Results
7.2.1 Flood Levels, Extents and Flow Distribution
Peak height profiles for the Extreme event and all other modelled design flood events are shown
on Figure 21. A summary of design flood levels at model cross-sections is presented in Table 12.
A detailed listing of the design flood results (peak flood levels, flows and velocities) at locations
throughout the model reaches is provided in Appendix D.
A GIS-based representation of the design flood levels at each of the model cross-sections is shown
on Figures 22 to 29 for each event. The extent of inundation is also included for the 100 Year ARI,
20 Year ARI and Extreme flood events on Figures 24, 26 and 29 respectively. It should be noted
that these extents are indicative only and have been determined based upon the processed survey
data used to define the model cross-sections. It is recommended that the actual extent for any
given location be confirmed with detailed local survey. The corresponding electronic GIS datafiles
used to produce these figures have been provided for use in Council’s GIS database. These files
have been generated for each event and indicate details of the peak discharge, peak flood level
and peak velocity at each model cross-section. It is imperative that this GIS-based information be
interpreted in the context of the information presented in this report. Importantly, the GIS
information should be interpreted from a broad perspective that takes into account the overall
floodplain as opposed to an interpretation that considers the results in isolation or on a localised
basis only. The metadata for the GIS information includes a reference to this report to assist
Council in this regard.
Given that detailed cross-section information was available at a limited number of locations and in
accordance with the 1D modelling approach adopted, an estimate of the flow distribution across
the floodplain was made on the basis of relative conveyance across each cross-section. An
example of the resulting flow distribution estimates at a cross-section is shown on Figure 30. This
type of information has been produced for all the design events and has been provided to Council
in digital form for direct incorporation into their internal GIS.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18August 2004 24
Table 12: Summary of Design Flood Levels
Chainage fromHawkesbury River
(m)
Location 500 Year ARI 200 Year ARI 100 Year ARI 50 Year ARI 20 Year ARI 5 Year ARI
Level
(mAHD)
Flow
(m3/s)
Level
(mAHD)
Flow
(m3/s)
Level
(mAHD)
Flow
(m3/s)
Level
(mAHD)
Flow
(m3/s)
Level
(mAHD)
Flow
(m3/s)
Level
(mAHD)
Flow
(m3/s)
1570 9.5 5497 8.0 4290 6.7 3430 5.6 2630 4.4 1810 3.2 753
3675 9.5 5500 8.0 4290 6.9 3430 6.1 2640 5.2 1820 3.7 753
4570 9.5 5500 8.0 4290 7.4 3430 6.5 2640 5.6 1820 3.9 753
6100 9.7 5500 8.8 4290 8.1 3440 7.2 2640 6.2 1830 4.4 754
8210 10.9 5510 9.9 4300 9.1 3440 8.3 2640 7.3 1820 5.5 755
9990 11.6 5470 10.6 4260 9.8 3420 9.0 2630 8.0 1810 6.2 752
11380 12.2 5470 11.2 4270 10.3 3420 9.4 2630 8.4 1810 6.5 752
14010 Wrights Ck 12.9 5200 11.9 4070 11.0 3260 10.1 2510 8.9 1740 7.0 718
16960 13.8 5180 12.7 4050 11.8 3250 10.8 2510 9.6 1740 7.6 717
19950 15.5 5070 14.3 3970 13.5 3190 12.5 2460 11.5 1710 8.9 704
22185 St Albans 16.7 5070 15.5 3970 14.6 3190 13.7 2460 12.6 1710 9.8 705
23330 17.1 5060 15.9 3970 15.0 3190 14.1 2460 13.0 1710 10.1 705
24380 17.3 5060 16.2 3960 15.3 3190 14.3 2460 13.2 1710 10.3 707
26280 17.4 5080 16.2 3980 15.4 3200 14.4 2470 13.3 1720 10.5 718
27270 18.0 4380 16.8 3430 15.9 2750 14.9 2130 13.8 1480 11.0 608
28110 18.2 4380 17.0 3430 16.1 2750 15.1 2130 13.9 1480 11.2 608
29490 18.7 4360 17.6 3410 16.7 2740 15.7 2120 14.4 1480 11.8 606
31280 Womerah Ck 19.3 4360 18.1 3420 17.2 2750 16.2 2120 15.0 1480 12.5 607
32800 19.8 4210 18.6 3300 17.7 2650 16.8 2050 15.5 1430 13.1 587
Lower MacDonald River Flood Study
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7.2.2 Provisional Flood Hazard and Hydraulic Categorisation
For the purposes of floodplain risk management in NSW the floodplain is broadly divided into one
of three Hydraulic categories (floodway, flood storage or flood fringe) and two Provisional Hazard
categories (Low or High). Further details of this process are outlined in the NSW Government’s
Floodplain Management Manual (January 2001, Reference 8).
Maps of the provisional hydraulic hazard (velocity x depth product) for the 100 Year ARI and
Extreme events are provided on Figures 31 and 32. For the purposes of the present study, the
provisional flood hazard has been determined at the model cross-sections in accordance with the
following criteria:
C High Flood Hazard: Assigned where the depth of flow or ‘velocity x depth’ product is
greater than one. The flow velocity used in the determination of the velocity x depth
product was the equivalent average velocity determined from the corresponding peak
discharge and local conveyance calculations across each cross-section.
C Low Flood Hazard: All other segments of the cross-section.
In view of the limited topographic data available, the conservative approach above was considered
appropriate given the significant depth of flow across the floodplain for the 100 Year ARI and
Extreme flood events and the one-dimensional flow behaviour of the system. The results indicate
that the Macdonald River floodplain is predominantly a high-hazard area for larger events. This
outcome is consistent with the confined nature of the floodplain and the relatively steep topography
bounding the floodplain along the lower Macdonald River.
The hydraulic categorisation was determined qualitatively based upon the available hydraulic and
survey information together with our knowledge of the Macdonald River catchment and experience
in similar rural to semi-rural floodplains. Due to the relatively confined nature of the floodplain, the
majority of the floodplain modelled for the present study conveys significant flow and functions
primarily as a ‘floodway’ as defined in the NSW Floodplain Management Manual (Reference 8).
In view of the linear nature of the flood behaviour and considering the limited survey data available,
the broad classification of ‘floodway’ is considered reasonable. This classification is made with an
acknowledgement that there may exist a limited area immediately adjacent to the floodway extent
that could be classed as ‘flood fringe’ where the depth of flow is less 0.5m. The exact delineation
of this hydraulic category can only be verified following detailed survey. Other areas subject to
backwater flooding from the Macdonald River have also been classed as ‘flood fringe’ in
accordance with Appendix G of Reference 8.
The constrained nature of the floodplain and the comparative volume of catchment runoff for larger
design events effectively limits the delineation of ‘flood storage’ for the Lower Macdonald floodplain.
Although the component of Flood Storage (as defined by the Manual) is likely to be significant over
the length of the Macdonald River floodplain, this particular component has been considered to be
incorporated within the area nominated as ‘floodway’ for the purposes of the present study. This
approach takes into account the available data throughout the area and the likely flood behaviour
of the system.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August 2004 26
7.2.3 Provisional Categorisation of Flood Prone Land
Due to the limited availability of comprehensive survey information, detailed and precise category
mapping of the floodplain was not possible. However, following consideration of the likely flood
behaviour of the system and in view of the classifications discussed in Section 7.2.2, it is suggested
that the flood prone land within the detailed study area be provisionally categorised in accordance
with Table 13 and the following. A mapped representation of this categorisation is shown on Figure
33 for the 100 Year ARI event. It is important to acknowledge that the categories described in this
Section are only provisional pending further assessment and refinement as part of the subsequent
Floodplain Risk Management Study and Plan (FRMS&P).
A number of zones have been defined along the Macdonald River to better account for differences
in the flood behaviour within different reaches. For the purposes of categorising the 100 Year ARI
event in the lower-most reaches (Zones A and B), an allowance has been made for the influence
of backwater flooding due to events on the Hawkesbury River. For example, it is likely that the
depths will be high yet the flow velocities will be moderate, during backwater flooding of this region
especially when compared with typical velocities likely to be experienced further upstream. Hence,
an allowance has been made for the categorisation in this reach where the depths are between
0.5m and 1m. In contrast, Zones C and E represent reaches where the flow velocities are relatively
higher and hence anywhere where the depths are greater than 0.5m can be regarded as being High
Hazard Floodway. Zone B represents a transitional zone between Zones A and C. Zone D covers
a reach where there is a distinct change in waterway area and a corresponding decrease in
expected flow velocity for the 100 Year ARI event.
When interpreting this information, it should be noted that the due to the relatively confined nature
of the floodplain, the lower Macdonald River is likely to experience a significant range in flood levels
across different flood frequencies, particularly for the larger events. Accordingly, it is critical that
management and planning decisions also address the issues associated with large floods between
the 100 Year ARI event and the Extreme event. For the purposes of the present study, it is
suggested that the area of flood prone land between the 100 Year ARI and Extreme flood extents
be provisionally classified as Low Hazard Flood Fringe (refer to Table 13). The additional flood
risks associated with events of this magnitude will need to be developed and considered as part
of the Floodplain Risk Management Study and Plan (FRMS&P) for the Lower Macdonald River.
It should also be noted that the categorisation has been prepared following consideration of a
number of factors including the natural flood behaviour, modelling assumptions, available
topographic data and the types of future development likely occur within the floodplain. For
example, it is expected that any future development would be restricted to free-standing
developments of a rural nature, constructed in isolation. This would be typical of the existing types
of development currently found within the valley.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August 2004 27
Table 13: 100 Year ARI Event - Provisional Flood Categorisation
Location(refer to
Figure 33)
ConditionsFlood
Category
Provisional
Hydraulic
Hazard
Comments
Zone A Flood Depth > 1.0m Floodway HighThis reach is subject to flooding from
both the Macdonald River catchment
and backwater from the Hawkesbury
River. The exact delineation between
'flood fringe' and 'floodway' is not
possible without detailed survey.
0.5m < Flood Depth < 1.0m Floodway Low
Flood Depth < 0.5mFlood
FringeLow
Zone B Flood Depth > 0.5m Floodway High
Flood Depth < 0.5mFlood
FringeLow
This classification can only be applied to
those areas which are immediately
adjacent to the 'floodway' area.
Zone C Flood Depth > 0.5m Floodway HighFor areas of the floodplain generally
bounded by St Albans Road and Settlers
Road.Flood Depth < 0.5m
(within 100 Year ARI flood
extent)
Flood
StorageHigh/Low
This classification can only be applied to
those areas which are immediately
adjacent to the 'floodway' area above.
Flood Depth > 1mFlood
FringeHigh
There are numerous areas in this region
that will be subject to backwater flooding
from the Macdonald River. These are as
indicated on Figure 33.
Zone D Flood Depth > 1m Floodway High
Located approximately 1.7km upstream
of St Albans, this particular area exhibits
a large change in waterway area and a
corresponding decrease in flow velocity.0.5m < Flood Depth < 1m Floodway Low
Flood Depth < 0.5m
(within 100 Year ARI flood
extent)
Flood
StorageLow
Zone E Flood Depth > 0.5m Floodway HighFor the reaches of the Macdonald River
upstream of Zone D and downstream of
the Womerah Creek junction.Flood Depth < 0.5m
(within 100 Year ARI flood
extent)
Flood
StorageHigh/Low
This classification can only be applied to
those areas which are immediately
adjacent to the 'floodway' area above.
Flood Depth < 0.5mFlood
FringeLow
This classification can only be applied to
those areas which are immediately
adjacent to the 'floodway' area noted
above.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August 2004 28
7.3 Comparison of the 100 Year ARI Design Event With the 1949 Flood
Given that the 100 Year ARI design event and the 1949 historical event are similar in magnitude
at St Albans, the estimated flood levels for the 100 Year ARI event were compared to available
observed levels along the Macdonald River. The corresponding peak flood height profiles are
presented on Figure 34. For completeness, the corresponding information for the March 1978
event is also included on the same plot.
An initial review of the historical data shown on Figure 34 indicates that there is a large degree of
uncertainty in the observed levels, with variations of up to 0.8m within the vicinity of St Albans and
corresponding discrepancies of approximately 1.5m at Wrights Creek. Furthermore, the observed
level of 14.2 mAHD just upstream of St Albans Commons is lower than any of the observed levels
at St Albans which range from 14.25 mAHD to 15.0 mAHD.
However, from a general perspective, Figure 34 shows that the estimated 100 Year ARI peak
height profile from St Albans to Wrights Creek either matches or slightly over-estimates the general
shape of the observed profile for the 1949 event. This trend lends confidence in the model results
obtained for the 100 Year ARI event which is a key event for planning purposes.
It is interesting to note that the model over-estimates the 1949 levels in the uppermost reaches
beyond St Albans. This behaviour is in contrast to the modelled behaviour for the March 1978
event where the model underestimated the observed levels in these locations. Although this
outcome justifies the adopted model calibration adopted to a certain extent, it serves to highlight
the degree of uncertainty present in the flood analysis undertaken for the Lower Macdonald River
floodplain. It is important that the interpretation of the design flood behaviour and selection of an
appropriate freeboard for planning purposes take these issues into account.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August 2004 29
8. CONCLUSION
This Flood Study of the Macdonald River constitutes the first stage of the floodplain risk
management process for this catchment. The information contained herein is suitable for the
preparation of a subsequent Floodplain Risk Management Study and Plan.
Making best use of available information, numerical models to quantify the historical flood behaviour
of the catchment were calibrated and verified. In conjunction with a flood frequency analysis
undertaken using streamflow data recorded at St Albans, the calibrated numerical models were
used to quantify the design flood behaviour of the Lower Macdonald River floodplain. Information
defining the flood behaviour for design events up to the 500 year ARI and the Extreme event was
produced.
The analysis and review of historical information show that there is a degree of uncertainty in the
records of past flooding within the study area. Available evidence also suggests that the Macdonald
River is morphologically active, with the shape and form of the channel bed and overbank areas
undergoing significant change following successive floods between 1949 and 1955. These factors
should be taken into consideration when interpreting the results of this study during the preparation
of the Floodplain Risk Management Study and Plan for the Lower Macdonald floodplain.
In view of these uncertainties, it is recommended that the expected order of accuracy for the design
flood levels is generally be between ±0.3 m to ±0.5 m. In view of the good model calibration and
verification achieved in the immediate vicinity of St Albans, the expected level of accuracy would
be in the order of ±0.3 m at this location.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August 2004 30
9. ACKNOWLEDGMENTS
This study was carried out by Webb, McKeown & Associates Pty Ltd and funded by Hawkesbury
City Council and the Department of Infrastructure, Planning and Natural Resources. The
assistance of the following in providing data and guidance to the study is gratefully acknowledged:
• Hawkesbury City Council staff and the Floodplain Management Committee,
• Department of Infrastructure, Planning and Natural Resources,
• Residents and landholders of the Macdonald River catchment.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August 2004 31
10. REFERENCES
1. H M Henry
Catastrophic Channel Changes in the Macdonald Valley, New South Wales 1949-
1955
Journal & Proceedings, Royal Society of New South Wales, Vol. 110, pp. 1-16, 1977.
2. Public Works Department
Warragamba Dam Auxiliary Spillway EIS Flood Study
Webb, McKeown & Associates, October 1996
3. Australian Water and Coastal Studies Pty Ltd
Lower Hawkesbury River Flood Study
AWACS Report No. 94/29, 1997.
4. D H Pilgrim (Editor in Chief)
Australian Rainfall and Runoff - A Guide to Flood Estimation
Institution of Engineers, Australia, 1987.
5. DHI Water and Environment
Mike-11 Users Guide and Reference Manual V2003
6. M A Walsh, D H Pilgrim and I Cordery
Initial Losses for Design Flood Estimation in New South Wales
International Hydrology and Water Resources Symposium Proceedings, pp283-288, 1991.
7. G Kuczera
FLIKE Version 4.50 Software Manual
Department of Civil, Surveying and Environmental Engineering, University of Newcastle,
2001.
8. New South Wales Government
Floodplain Management Manual: The management of flood liable land
January 2001.
FIGURESFIGURES
306000
306000
308000
308000
310000
310000
312000
312000
314000
314000
316000
316000
6306
000
6306
000
6308
000
6308
000
6310
000
6310
000
6312
000
6312
000
6314
000
6314
000
6316
000
6316
000
6318
000
6318
000
FIGURE 1STUDY AREA
0 30 km
¯
Study Catchment
Detailed Study Area
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
!.
!.
!.
!.
!.
!.
!.
306000
306000
308000
308000
310000
310000
312000
312000
314000
314000
6306
000
6306
000
6308
000
6308
000
6310
000
6310
000
6312
000
6312
000
6314
000
6314
000
6316
000
6316
000
6318
000
6318
000
FIGURE 2AVAILABLE SURVEY DATA
!. PWD Hydrosurvey
GPS Survey Data
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
500 0 500 1,000 1,500 2,000250
Metres
#
#
#
#
#
#
#
#
BALA
WOMERAH
LAMBTON
MT CALORE
ST ALBANS
PUTTY (THE GIBBA)
PUTTY FOREST (3WAYS)
COLO HEIGHTS COMPOSITE
ST ALBANS (MOGO CREEK)
HOWES VALLEY (KINDARUN)
HOWES VALLEY (OWENSDALE)
HOWES VALLEY (NOISY POINT)
PEATS RIDGE (WARATAH ROAD)
LOWER PORTLAND (ORANGE GROVE)
MANGROVE MOUNTAIN (DUBBO GULLY)
WISEMANS FERRY (OLD POST OFFICE)
PUTTY POST OFFICE (PUTTY COMPOSITE)
270000
270000
280000
280000
290000
290000
300000
300000
310000
310000
320000
320000
330000
330000
6290
000
6300
000
6300
000
6310
000
6310
000
6320
000
6320
000
6330
000
6330
000
6340
000
6340
000
6350
000
6350
000
6360
000
6360
000
6370
000
6370
000
6380
000
6380
000
FIGURE 3LOCATIONS OF RAINFALL STATIONS
Rainfall Stations# Pluviograph
Daily Read
Hawkesbury River
Webbs Ck Wrights Ck
Macdonald R
iver
0 4 8 12 16Km
BIG_BOREE
MELON_CK
BOGGY
LOWER_MOGO
PALONA_CK
MALONG
NOISY_PT
WRIGHTS_CK
LOWER_YENGO
UPPER_HOWES
UPPER_MOGO
UPPER_MAC
APPLETREE
REEDY_CK
MARLO_CK
UPPER_YENGO
BURROWELL_CK
CALORIE_CK
TOORWAI_CK
WOMERAH_CK
PALOMORANG
MT_YENGO
WELLUMS_CK
THOMPSON
BAILEY_CK
LOWER_HOWES
FORBES_CK
LOWER_MAC
UPPER_ST_ALBANS
FLEMINGS
ST_ALBANS
COLO_CK
MIDDLE_MAC
UPPER_COMM
270000
270000
280000
280000
290000
290000
300000
300000
310000
310000
320000
320000
330000
330000
6300
000
6300
000
6310
000
6310
000
6320
000
6320
000
6330
000
6330
000
6340
000
6340
000
6350
000
6350
000
6360
000
6360
000
6370
000
6370
000
6380
000
6380
000
FIGURE 4WBNM MODEL LAYOUT
WBNM Sub-Areas Hawkesbury River
Webbs Ck Wrights Ck
Macdonald R
iver
0 4 8 12 16Km
FIGURE 5
HISTORICAL RAINFALL DATA
MARCH 1978 EVENT
PUTTY POST OFFICEPUTTY (THE GIBBA)
200
200
250
300
300
250
200
150
150
200
187
286
118
ISOHYETAL MAP96HRS FROM 0900 18/3/78
SOURCE:WARRAGAMBA DAM AUXILLARY SPILLWAYEIS FLOOD STUDY - PART B (1996)
(REFERENCE 2)
Ra
infa
ll(m
m)
Ra
infa
ll(m
m)
250
250
FIGURE 6
HISTORICAL RAINFALL DATA
AUGUST 1990 EVENT
MT CALOREDUBBO GULLY
Rain
fall
(mm
)
WOMERAHNOISY POINT
Rain
fall
(mm
)
Rain
fall
(mm
)R
ain
fall
(mm
)
150
150
100
100
146.50
136.50
119
141 153
163
102.5
82
97
71
ISOHYETAL MAP96HRS FROM 0000 31/7/90
SOURCE:WARRAGAMBA DAM AUXILLARY SPILLWAYEIS FLOOD STUDY - PART B (1996)
(REFERENCE 2)
FIGURE 7
HISTORICAL RAINFALL DATA
APRIL 1988 EVENT
100
100
150
150
50
50
20
20
120
38
ISOHYETAL MAP96HRS FROM 0900 27/4/1988
Ra
infa
ll(m
m)
Ra
infa
ll(m
m)
PEATS RIDGECOLO HEIGHTS
SOURCE:WARRAGAMBA DAM AUXILLARY SPILLWAYEIS FLOOD STUDY - PART B (1996)
(REFERENCE 2)
FIGURE 8
HISTORICAL RAINFALL DATA
AUGUST 1986 EVENT
COLO HEIGHTS
250
250
300
300
200200
150
150
ISOHYETAL MAP72HRS FROM 0000 4/8/86
Ra
infa
ll(m
m)
SOURCE:WARRAGAMBA DAM AUXILLARY SPILLWAYEIS FLOOD STUDY - PART B (1996)
(REFERENCE 2)
FIGURE 9
Discharge(m3/s)
Tim
e(
hours
from
0900
18/3
/1978
)
FLOW HYDROGRAPHS
MARCH 1978 CALIBRATION EVENT
FIGURE 10
FLOW HYDROGRAPHS
AUGUST 1990 VERIFICATION EVENT
Tim
e(
hours
from
0000
31/0
7/9
0)
Discharge(m3/s)
FIGURE 11
FLOW HYDROGRAPHS
APRIL 1988 EVENT
Tim
e(
hours
from
0900
27/4
/1988
)
Discharge(m3/s)
FIGURE 12
FLOW HYDROGRAPHS
AUGUST 1986 VERIFICATION EVENT
Tim
e(
hours
from
0000
4/8
/86
)
Discharge(m3/s)
8420 m
0 m
31230 m
9470 m
29125 m
21420 m
22810 m
24590 m
4690 m
18790 m
3310 m
10615 m
1520 m
26700 m
6520 m
12850 m
1260 m
5530 m
15840 m
0 m
305000
305000
310000
310000
315000
315000
6305
000
6310
000
6310
000
6315
000
6315
000
FIGURE 13MIKE11 MODEL LAYOUT
Cross-section & MIKE11 ChainageE Lateral Inflow
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
500 0 500 1,000 1,500 2,000
Metres
EE
E
E
E E
E
E
FIG
UR
E 14
CO
MP
AR
ISO
N W
ITH
AV
AIL
AB
LE
DA
TA
M
AR
CH
1978 CA
LIB
RA
TIO
N E
VE
NT
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
0 5000 10000 15000 20000 25000 30000
Chainage from Hawkesbury River Confluence (m)
Hei
gh
t (m
AH
D)
MIKE11 Peak Flood Profile
MIKE11 100 Year Event
Observed Level (Source: HCC Council Profile 1984)
Observed Level (Source: 2003 GPS Field Survey)
Location Identifiers
St.
Alb
ans
Com
mon
St A
lban
s
Wrig
hts
Cre
ek
FIGURE 15STAGE HYDROGRAPHS AT ST ALBANS
MARCH 1978 CALIBRATION EVENT
1
2
3
4
5
6
7
8
9
10
11
12
18/03/19780:00
19/03/19780:00
20/03/19780:00
21/03/19780:00
22/03/19780:00
23/03/19780:00
24/03/19780:00
25/03/19780:00
Hei
ght (
m A
HD
)
MIKE11 Results
Observed Stage (Station 212010)
FIGURE 16FLOW HYDROGRAPHS AT ST ALBANS
MARCH 1978 CALIBRATION EVENT
0
100
200
300
400
500
600
700
800
900
1000
18/03/19780:00
19/03/19780:00
20/03/19780:00
21/03/19780:00
22/03/19780:00
23/03/19780:00
24/03/19780:00
25/03/19780:00
MIKE11 Results
Estimated Flow (Station 212010)
Flow
(m3 /s
)
FIGU
RE
17PEA
K H
EIGH
T PRO
FILEA
UG
UST 1990 VER
IFICA
TION
EVENT
3
4
5
6
7
8
9
10
11
12
13
0 5000 10000 15000 20000 25000 30000
Chainage from Hawkesbury River Confluence (m)
Hei
ght (
m A
HD
)
MIKE11 Peak Height Flood ProfileObserved Level (Source: DIPNR Station 212010)Location Identifiers
St.
Alb
ans
Com
mon
St A
lban
s
Wrig
hts
Cre
ek
FIGURE 18STAGE HYDROGRAPHS AT ST ALBANS
AUGUST 1990 VERIFICATION EVENT
1
2
3
4
5
6
7
8
9
1/08/1990 0:00 2/08/1990 0:00 3/08/1990 0:00 4/08/1990 0:00
Hei
ght
(m A
HD
)
MIKE11 Results
Observed Stage (Station 212010)
FIGURE 19FLOW HYDROGRAPHS AT ST ALBANS
AUGUST 1990 VERIFICATION EVENT
0
100
200
300
400
500
1/08/1990 0:00 2/08/1990 0:00 3/08/1990 0:00 4/08/1990 0:00
MIKE11 Results
Observed Flow (Station 212010)
Flow
(m3 /s
)
LP3 fit (gauge data only)
90% Conf. Limit
90% Conf.
Data Point
LP3 fit (including 1949 event)
90% Conf. Limit
90% Conf.
Data Point
FIGURE 20
FLOOD FREQUENCY
ANALYSES
1949 Event
FIL
E>
J:\
JO
BS
\22
03
2\A
DM
IN\F
IGU
RE
S\ffa
.cd
rD
AT
E>
Fe
bru
ary
20
04
WBNM Flow Estimates(adjusted for annual series comparison)
WBNM Flow Estimates(adjusted for annual series comparison)
FIG
UR
E 21
PE
AK
HE
IGH
T P
RO
FIL
ES
DE
SIG
N F
LO
OD
EV
EN
TS
MA
CD
ON
AL
D R
IVE
R
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
0 5000 10000 15000 20000 25000 30000
Chainage from Hawkesbury River Confluence (m)
Hei
gh
t (m
AH
D)
500 Year ARI 200 Year ARI
100 Year ARI 50 Year ARI
5 Year ARI Extreme Event
Location Identifiers
St.
Alb
ans
Com
mon
St A
lban
s
Wri
ghts
Cre
ek
9.5
17.3
9.7
12.2
18
11.6
10.9
12.9
17.1
18.2
16.7
18.7
15.5
19.3
17.4
13.8
19.8
12.9
9.5
12.9
9.5
500 Year ARI Peak Flood Height (m AHD)
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 22DESIGN FLOOD HEIGHTS
500 YEAR ARI EVENT
NOTE: Inundation Extents Not Shown
500 0 500 1,000 1,500Metres
8
16.2
17
9.9
8.8
11.1
10.6
11.9
15.9
11.8
15.5
17.6
14.3
18.1
12.7
16.818.6
16.2
88
11.8
200 Year ARI Peak Flood Height (m AHD)
NOTE: Inundation Extents Not Shown
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 23DESIGN FLOOD HEIGHTS
200 YEAR ARI EVENT
500 0 500 1,000 1,500Metres
15.3
6.711
159.1
7.4
6.9
9.8
8.1
10.3
16.7
16.1
17.2
13.5
15.4
11.8
15.9
14.6
17.7
11
11
100 Year ARI Peak Flood Height (m AHD)
NOTE: Extents shown at each location are indicative only and may be limited by limit of available survey. The actual extent should be confirmed with detailed local survey.
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 24DESIGN FLOOD HEIGHTS AND EXTENTS
100 YEAR ARI EVENT
500 0 500 1,000 1,500Metres
9
5.6
14.36.5
10
6.1
9.4
8.3
7.2
10.1
14.1
15.1
13.7
15.7
12.5
16.2
14.4
10.8
14.916.8
10
50 Year ARI Peak Flood Height (m AHD)
NOTE: Inundation Extents Not Shown
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 25DESIGN FLOOD HEIGHTS
50 YEAR ARI EVENT
500 0 500 1,000 1,500Metres
8
13.2
137.3
8.4
8.9
4.4
5.25.6
6.2
15
9.6
14.4
11.5
13.3
13.815.5
12.6
13.9
8.9
8.9
20 Year ARI Peak Flood Height (m AHD)
NOTE: Extents shown at each location are indicative only and may be limited by limit of available survey. The actual extent should be confirmed with detailed local survey.
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 26DESIGN FLOOD LEVELS AND EXTENTS
20 YEAR ARI EVENT
500 0 500 1,000 1,500Metres
7
3.9
12.14.7
4.4
7.4
6.3
7.9
5.2
11.9
8.6
12.711
.6
13.2
10.6
13.8
12.2
12.614.3
7.9
7.9
10 Year ARI Peak Flood Height (m AHD)
NOTE: Inundation Extents Not Shown
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 27DESIGN FLOOD HEIGHTS
10 YEAR ARI EVENT
500 0 500 1,000 1,500Metres
7
3.2
10.33.9
3.7
6.5
6.2
5.5
9.8
4.4
8.911
10.1
7.6
11.2
11.812.5
10.5
13.1
7
7
5 Year ARI Peak Flood Height (m AHD)
NOTE: Inundation Extents Not Shown
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 28DESIGN FLOOD HEIGHTS
5 YEAR ARI EVENT
500 0 500 1,000 1,500Metres
20.4
20
16.3
19.6
21.9
21.3
22.5
18.4
20.3
16.6
20.922.9
16.316.3
16.3
16.3
16.316.3
16.3
16.3
16.3
Extreme Event Peak Flood Height (m AHD)
NOTE: Extents shown at each location are indicative only and may be limited by limit of available survey. The actual extent should be confirmed with detailed local survey.
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 29DESIGN FLOOD HEIGHTS AND EXTENTS
EXTREME FLOOD EVENT
500 0 500 1,000 1,500Metres
9
8.4
1.57
6.34.9
8.7
3.5
4.74.2
4.4
3.3
6.21.95.2
3.1
3.7
1.2
2.6 2.2 0.2
1.66.3
% Flow Distribution Across Cross-section
Macdonald River
FIGURE 30EXAMPLE OF FLOW DISTRIBUTION
AT MODEL CROSS-SECTIONS100 YEAR ARI EVENT
10 0 10 20 30 40 50Metres
High Flood Hazard
Low Flood Hazard
NOTE: Extents shown at each location are indicative only and may be limited by limit of available survey. The actual extent should be confirmed with detailed local survey.
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 31PROVISIONAL FLOOD HAZARD
AT CROSS-SECTIONS100 YEAR ARI EVENT
500 0 500 1,000 1,500Metres
High Flood Hazard
Low Flood Hazard
NOTE: Extents shown at each location are indicative only and may be limited by limit of available survey. The actual extent should be confirmed with detailed local survey.
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 32PROVISIONAL FLOOD HAZARD
AT CROSS-SECTIONSEXTREME FLOOD EVENT
500 0 500 1,000 1,500Metres
NOTE: The information shown should be interpreted in conjunction with Table 13 and Section 7 of the Lower Macdonald Flood Study Report.
St Albans
Hawkesbury River
Webbs Ck
Wrights Ck
Womerah Ck
Macdonald River
FIGURE 33CATEGORISATION OF FLOOD PRONE LAND
Extent of Modelling
Outside of Detailed Study Area
Outside of Detailed Study Area
Outside of Detailed Study Area
Extent of Modelling
A
B
C
D
E
LEGENDIndicative Extent of Flood Fringe
Indicative Extent of Floodway
Zone (Refer to Table 13)A
NOTE: The exact delineation between 'flood fringe' and 'floodway' in this area is subject to detailed survey.
0 500 1,000 1,500 2,000250Metres
FIG
UR
E 34
PE
AK
HE
IGH
T P
RO
FIL
ES
MA
CD
ON
AL
D R
IVE
R 100 Y
EA
R A
RI D
ES
IGN
EV
EN
T A
ND
1949 HIS
TO
RIC
AL
EV
EN
TS
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
0 5000 10000 15000 20000 25000 30000
Chainage from Hawkesbury River Confluence (m)
Hei
gh
t (m
AH
D)
100 Year ARI Design Event MIKE 11 Peak Flood Profile
1978 Event MIKE11 Peak Flood Profile
1949 Observed Levels
March 1978 Observed Level (Source: HCC)
March 1978 Observed Level (Source: GPS Survey)
Location Identifiers St.
Alb
ans
Com
mon
St A
lban
s
Wri
ghts
Cre
ek
APPENDIX A:APPENDIX A: GLOSSARY OF FLOOD RELATED TERMS
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August, 2004 A1
APPENDIX A: GLOSSARY OF TERMS
Annual ExceedanceProbability (AEP)
The chance of a flood of a given or larger size occurring in any one year, usuallyexpressed as a percentage. For example, if a peak flood discharge of 500 m 3/s hasan AEP of 5%, it means that there is a 5% chance (that is one-in-20 chance) of apeak flood discharge of 500 m3/s or larger occurring in any one year (see averagerecurrence interval).
Australian Height Datum(AHD)
A common national surface level datum approximately corresponding to mean sealevel.
Average Annual Damage(AAD)
Depending on its size (or severity), each flood will cause a different amount of flooddamage to a flood prone area. AAD is the average damage per year that wouldoccur in a nominated development situation from flooding over a very long periodof time.
Average RecurrenceInterval (ARI)
The long term average number of years between the occurrence of a flood as bigas, or larger than, the selected event. For example, floods with a discharge asgreat as, or greater than, the 20 year ARI flood event will occur on average onceevery 20 years. ARI is another way of expressing the likelihood of occurrence of aflood event.
catchment The land area draining through the main stream, as well as tributary streams, to aparticular site. It always relates to an area above a specific location.
development Is defined in Part 4 of the Environmental Planning and Assessment Act (EP&A Act).
infill development: refers to the development of vacant blocks of land that aregenerally surrounded by developed properties and is permissible under the currentzoning of the land. Conditions such as minimum floor levels may be imposed oninfill development.
new development: refers to development of a completely different nature to thatassociated with the former land use. For example, the urban subdivision of an areapreviously used for rural purposes. New developments involve rezoning andtypically require major extensions of existing urban services, such as roads, watersupply, sewerage and electric power.
redevelopment: refers to rebuilding in an area. For example, as urban areas age,it may become necessary to demolish and reconstruct buildings on a relatively largescale. Redevelopment generally does not require either rezoning or majorextensions to urban services.
discharge The rate of flow of water measured in terms of volume per unit time, for example,cubic metres per second (m3/s). Discharge is different from the speed or velocityof flow, which is a measure of how fast the water is moving for example, metres persecond (m/s).
flash flooding Flooding which is sudden and unexpected. It is often caused by sudden local ornearby heavy rainfall. Often defined as flooding which peaks within six hours of thecausative rain.
flood Relatively high stream flow which overtops the natural or artificial banks in any partof a stream, river, estuary, lake or dam, and/or local overland flooding associatedwith major drainage before entering a watercourse, and/or coastal inundationresulting from super-elevated sea levels and/or waves overtopping coastlinedefences excluding tsunami.
flood fringe areas The remaining area of flood prone land after floodway and flood storage areas havebeen defined.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August, 2004 A2
flood liable land Is synonymous with flood prone land (i.e. land susceptible to flooding by theprobable maximum flood (PMF) event). Note that the term flood liable land nowcovers the whole of the floodplain, not just that part below the flood planning level,as indicated in the 1986 Floodplain Development Manual (see flood planning area).
floodplain Area of land which is subject to inundation by floods up to and including theprobable maximum flood event, that is, flood prone land.
Flood Planning Levels(FPLs)
The combination of flood levels and freeboards selected for planning purposes, asdetermined in floodplain risk management studies and incorporated in floodplainrisk management plans. The concept of flood planning levels supersedes the“standard flood event” of the first edition of this manual.
flood prone land Is land susceptible to flooding by the Probable Maximum Flood (PMF) event. Floodprone land is synonymous with flood liable land.
flood risk Potential danger to personal safety and potential damage to property resulting fromflooding. The degree of risk varies with circumstances across the full range offloods. Flood risk in this manual is divided into 3 types, existing, future andcontinuing risks. They are described below.
existing flood risk: the risk a community is exposed to as a result of its locationon the floodplain.
future flood risk: the risk a community may be exposed to as a result of newdevelopment on the floodplain.
continuing flood risk: the risk a community is exposed to after floodplain riskmanagement measures have been implemented. For a town protected by levees,the continuing flood risk is the consequences of the levees being overtopped. Foran area without any floodplain risk management measures, the continuing flood riskis simply the existence of its flood exposure.
flood storage areas Those parts of the floodplain that are important for the temporary storage offloodwaters during the passage of a flood. The extent and behaviour of floodstorage areas may change with flood severity, and loss of flood storage canincrease the severity of flood impacts by reducing natural flood attenuation. Hence,it is necessary to investigate a range of flood sizes before defining flood storageareas.
floodway areas Those areas of the floodplain where a significant discharge of water occurs duringfloods. They are often aligned with naturally defined channels. Floodways areareas that, even if only partially blocked, would cause a significant redistribution offlood flows, or a significant increase in flood levels.
hazard A source of potential harm or a situation with a potential to cause loss. In relationto this manual the hazard is flooding which has the potential to cause damage tothe community. Definitions of high and low hazard categories are provided in theFloodplain Management Manual.
hydraulics Term given to the study of water flow in waterways; in particular, the evaluation offlow parameters such as water level and velocity.
hydrograph A graph which shows how the discharge or stage/flood level at any particularlocation varies with time during a flood.
hydrology Term given to the study of the rainfall and runoff process; in particular, theevaluation of peak flows, flow volumes and the derivation of hydrographs for arange of floods.
local overland flooding Inundation by local runoff rather than overbank discharge from a stream, river,estuary, lake or dam.
local drainage Are smaller scale problems in urban areas. They are outside the definition of majordrainage in this glossary.
Lower MacDonald River Flood Study
Webb, McKeown & Associates Pty Ltd22032:MacRiverFSFinal.wpd:18 August, 2004 A3
mainstream flooding Inundation of normally dry land occurring when water overflows the natural orartificial banks of a stream, river, estuary, lake or dam.
major drainage Councils have discretion in determining whether urban drainage problems areassociated with major or local drainage. For the purpose of this manual majordrainage involves:• the floodplains of original watercourses (which may now be piped,
channelised or diverted), or sloping areas where overland flows developalong alternative paths once system capacity is exceeded; and/or
• water depths generally in excess of 0.3 m (in the major system designstorm as defined in the current version of Australian Rainfall andRunoff). These conditions may result in danger to personal safety andproperty damage to both premises and vehicles; and/or
• major overland flow paths through developed areas outside of defineddrainage reserves; and/or
• the potential to affect a number of buildings along the major flow path.
mathematical/computermodels
The mathematical representation of the physical processes involved in runoffgeneration and stream flow. These models are often run on computers due to thecomplexity of the mathematical relationships between runoff, stream flow and thedistribution of flows across the floodplain.
peak discharge The maximum discharge occurring during a flood event.
Probable Maximum Flood(PMF)
The largest flood that could conceivably occur at a particular location, usuallyestimated from probable maximum precipitation. Generally, it is not physically oreconomically possible to provide complete protection against this event. The PMFdefines the extent of flood prone land, that is, the floodplain. The extent, nature andpotential consequences of flooding associated with the PMF event should beaddressed in a Floodplain Risk Management study.
Probable MaximumPrecipitation (PMP)
The greatest depth of precipitation for a given duration meteorologically possibleover a given size storm area at a particular location at a particular time of the year,with no allowance made for long-term climatic trends (World MeteorologicalOrganisation, 1986). It is the primary input to the estimation of the probablemaximum flood.
probability A statistical measure of the expected change of flooding (see annual exceedanceprobability).
risk Chance of something happening that will have an impact. It is measured in termsof consequences and likelihood. In the context of the manual it is the likelihood ofconsequences arising from the interaction of floods, communities and theenvironment.
runoff The amount of rainfall which actually ends up as streamflow, also known as rainfallexcess.
stage Equivalent to “water level”. Both are measured with reference to a specifieddatum.
stage hydrograph A graph that shows how the water level at a particular location changes withtime during a flood. It must be referenced to a particular datum.
survey plan A plan prepared by a registered surveyor.
water surface profile A graph showing the flood stage at any given location along a watercourse at aparticular time.
wind fetch The horizontal distance in the direction of wind over which wind waves aregenerated.
APPENDIX B:APPENDIX B: PUBLISHED GEOMORPHOLOGICAL ANALYSIS OF MACDONALD RIVER
APPENDIX C:APPENDIX C: PHOTOGRAPHS OF HISTORICAL FLOOD LEVEL SURVEY SITES
FIG
UR
E C
1O
BS
ER
VE
D F
LO
OD
HE
IGH
TS
LO
NG
ITU
DIN
AL
PR
OF
ILE
OF
MA
CD
ON
AL
D R
IVE
R
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
0 5000 10000 15000 20000 25000 30000
Chainage from Hawkesbury River Confluence (m)
Hei
gh
t (m
AH
D)
100 Year ARI Design Event MIKE 11 Peak Flood Profile
1978 Event MIKE11 Peak Flood Profile
1949 Observed Levels
March 1978 Observed Level (Source: HCC)
March 1978 Observed Level (Source: GPS Survey)
Location Identifiers
St.
Alb
ans
Com
mon
St A
lban
s
Wri
ghts
Cre
ek
HCC Pt 441
HCC Pt 549
HCC Pt 1000
HCC Pt 151
HCC Pt 503
HCC Pt 526
HCC Pt 108
HCC Pt 105
HCC Pt 525
Point Number 1000As reported by Joyce Steptoe who remembers as a child in 1949 stepping out onepace to be in the waters of the ‘49 flood. This is only approximately 200 metresupstreamoftheSt.AlbansPub.Co-ordinates;E 310700,N6314250
1949RL 15.09
Point Number 5261949 Flood came to the bottom of the window sill on Cottage. Source Mrs Jord
from same property
RL 14.18
Point Number 525Change of grade near fence.
RL 14.18
RL 13.213
RL13.213
Point Number 525Change of grade near fence.
Point Number 503
Point Number 503
Point Number 503
Point Number 5031949 Flood came to the milk line in the old dairy. Source Ray Morris, owner.
Point Number 503View through dairy door to property’s homestead
Point Number 150Base Station “H” RL 12.437
Floods reached floor level of this old shed
RL 10.596Presumedto be
1978
Point Number 150Source Mrs L. Bailey (45682106)
Point Number 150
Point Number 150
APPENDIX D:APPENDIX D: DESIGN FLOOD RESULTS
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
River name Chainage from MIKE11 500 Year ARI 200 Year ARIHawkesbury River (m) Chainage (m) Flood Peak
(mAHD)Peak Discharge
(m3/s) Peak Velocity (m/s)Flood Peak
(mAHD)Peak Discharge
(m3/s) Peak Velocity (m/s)
MACDONALD RIVER 32800 0 19.8 4207 2.9 18.6 3299 2.7MACDONALD RIVER 32705 95 19.7 4207 2.8 18.6 3299 2.6MACDONALD RIVER 32610 190 19.7 4207 2.7 18.5 3299 2.5MACDONALD RIVER 32515 285 19.6 4207 2.6 18.5 3299 2.4MACDONALD RIVER 32420 380 19.6 4207 2.5 18.5 3299 2.4MACDONALD RIVER 32325 475 19.6 4207 2.5 18.4 3299 2.3MACDONALD RIVER 32230 570 19.5 4207 2.4 18.4 3299 2.2MACDONALD RIVER 32135 665 19.5 4207 2.3 18.4 3299 2.1MACDONALD RIVER 32040 760 19.5 4207 2.2 18.3 3299 2.1MACDONALD RIVER 31945 855 19.4 4206 2.2 18.3 3299 2.0MACDONALD RIVER 31850 950 19.4 4206 2.1 18.3 3299 1.9MACDONALD RIVER 31755 1045 19.4 4206 2.0 18.3 3299 1.9MACDONALD RIVER 31660 1140 19.4 4206 2.0 18.2 3299 1.8MACDONALD RIVER 31565 1235 19.4 4206 1.9 18.2 3299 1.8MACDONALD RIVER 31470 1330 19.3 4282 1.9 18.2 3356 1.8MACDONALD RIVER 31375 1425 19.3 4360 1.9 18.2 3416 1.7MACDONALD RIVER 31280 1520 19.3 4360 1.8 18.1 3416 1.7MACDONALD RIVER 31180.56 1619.44 19.3 4359 1.8 18.1 3416 1.7MACDONALD RIVER 31081.11 1718.89 19.2 4359 1.8 18.1 3415 1.7MACDONALD RIVER 30981.67 1818.33 19.2 4358 1.9 18.1 3415 1.7MACDONALD RIVER 30882.22 1917.78 19.2 4358 1.9 18.0 3415 1.7MACDONALD RIVER 30782.78 2017.22 19.1 4358 1.9 18.0 3414 1.7MACDONALD RIVER 30683.33 2116.67 19.1 4357 1.9 18.0 3414 1.7MACDONALD RIVER 30583.89 2216.11 19.1 4357 1.9 17.9 3414 1.7MACDONALD RIVER 30484.44 2315.56 19.1 4357 1.9 17.9 3414 1.7MACDONALD RIVER 30385 2415 19.0 4357 1.9 17.9 3414 1.7MACDONALD RIVER 30285.56 2514.44 19.0 4357 1.9 17.8 3413 1.7MACDONALD RIVER 30186.11 2613.89 19.0 4357 1.9 17.8 3413 1.7MACDONALD RIVER 30086.67 2713.33 18.9 4356 1.9 17.8 3413 1.7MACDONALD RIVER 29987.22 2812.78 18.9 4356 1.9 17.7 3413 1.7MACDONALD RIVER 29887.78 2912.22 18.9 4356 1.9 17.7 3413 1.7MACDONALD RIVER 29788.33 3011.67 18.8 4356 1.9 17.7 3413 1.7MACDONALD RIVER 29688.89 3111.11 18.8 4356 1.9 17.6 3413 1.7MACDONALD RIVER 29589.44 3210.56 18.8 4356 1.9 17.6 3413 1.8MACDONALD RIVER 29490 3310 18.7 4355 1.9 17.6 3413 1.8MACDONALD RIVER 29391.43 3408.57 18.7 4355 1.9 17.5 3412 1.8MACDONALD RIVER 29292.86 3507.14 18.7 4355 1.9 17.5 3412 1.8MACDONALD RIVER 29194.29 3605.71 18.6 4355 1.9 17.5 3412 1.8MACDONALD RIVER 29095.71 3704.29 18.6 4355 1.9 17.4 3412 1.8MACDONALD RIVER 28997.14 3802.86 18.6 4355 1.9 17.4 3412 1.8MACDONALD RIVER 28898.57 3901.43 18.5 4354 1.9 17.4 3412 1.8MACDONALD RIVER 28800 4000 18.5 4354 1.9 17.3 3412 1.8MACDONALD RIVER 28701.43 4098.57 18.4 4354 1.9 17.3 3412 1.8MACDONALD RIVER 28602.86 4197.14 18.4 4354 2.0 17.2 3412 1.8MACDONALD RIVER 28504.29 4295.71 18.4 4354 2.0 17.2 3412 1.8MACDONALD RIVER 28405.71 4394.29 18.3 4354 2.0 17.2 3411 1.9MACDONALD RIVER 28307.14 4492.86 18.3 4354 2.0 17.1 3411 1.9MACDONALD RIVER 28208.57 4591.43 18.3 4365 2.0 17.1 3420 1.9MACDONALD RIVER 28110 4690 18.2 4377 2.0 17.0 3428 1.9MACDONALD RIVER 28016.67 4783.33 18.2 4377 2.0 17.0 3428 1.9MACDONALD RIVER 27923.33 4876.67 18.2 4376 2.0 17.0 3428 1.8MACDONALD RIVER 27830 4970 18.1 4376 1.9 16.9 3428 1.8MACDONALD RIVER 27736.67 5063.33 18.1 4376 1.9 16.9 3428 1.8MACDONALD RIVER 27643.33 5156.67 18.1 4377 1.9 16.9 3428 1.8MACDONALD RIVER 27550 5250 18.0 4377 1.9 16.9 3428 1.8MACDONALD RIVER 27456.67 5343.33 18.0 4377 1.9 16.8 3428 1.7MACDONALD RIVER 27363.33 5436.67 18.0 4377 1.9 16.8 3428 1.7MACDONALD RIVER 27270 5530 18.0 4377 2.0 16.8 3429 1.8MACDONALD RIVER 27171 5629 17.9 4377 2.0 16.8 3429 1.8MACDONALD RIVER 27072 5728 17.8 4726 2.2 16.7 3702 1.9MACDONALD RIVER 26973 5827 17.7 5086 2.4 16.6 3986 2.1MACDONALD RIVER 26874 5926 17.7 5085 2.4 16.5 3985 2.2MACDONALD RIVER 26775 6025 17.6 5085 2.4 16.5 3985 2.2MACDONALD RIVER 26676 6124 17.6 5084 2.4 16.4 3984 2.2MACDONALD RIVER 26577 6223 17.5 5084 2.5 16.4 3983 2.2MACDONALD RIVER 26478 6322 17.5 5083 2.5 16.3 3983 2.3MACDONALD RIVER 26379 6421 17.4 5082 2.5 16.3 3982 2.3MACDONALD RIVER 26280 6520 17.4 5082 2.6 16.2 3981 2.5MACDONALD RIVER 26180 6620 17.4 5081 2.3 16.2 3981 2.1MACDONALD RIVER 26080 6720 17.3 5080 2.2 16.2 3980 2.0MACDONALD RIVER 25980 6820 17.3 5080 2.0 16.2 3980 1.8MACDONALD RIVER 25880 6920 17.3 5079 1.8 16.2 3979 1.7MACDONALD RIVER 25780 7020 17.3 5078 1.7 16.2 3978 1.6MACDONALD RIVER 25680 7120 17.3 5077 1.6 16.2 3977 1.4MACDONALD RIVER 25580 7220 17.3 5075 1.5 16.2 3976 1.3MACDONALD RIVER 25480 7320 17.3 5074 1.4 16.2 3976 1.3MACDONALD RIVER 25380 7420 17.3 5073 1.3 16.2 3975 1.2MACDONALD RIVER 25280 7520 17.3 5071 1.2 16.2 3974 1.1MACDONALD RIVER 25180 7620 17.3 5070 1.1 16.2 3973 1.0MACDONALD RIVER 25080 7720 17.3 5068 1.1 16.2 3971 1.0MACDONALD RIVER 24980 7820 17.3 5067 1.0 16.2 3970 0.9MACDONALD RIVER 24880 7920 17.3 5065 1.0 16.2 3969 0.9MACDONALD RIVER 24780 8020 17.3 5064 1.0 16.2 3968 1.0MACDONALD RIVER 24680 8120 17.3 5063 1.1 16.2 3966 1.1MACDONALD RIVER 24580 8220 17.3 5062 1.2 16.2 3965 1.2MACDONALD RIVER 24480 8320 17.3 5061 1.3 16.2 3965 1.3MACDONALD RIVER 24380 8420 17.3 5059 1.4 16.2 3964 1.4MACDONALD RIVER 24284.55 8515.45 17.3 5058 1.0 16.2 3963 1.0MACDONALD RIVER 24189.09 8610.91 17.3 5057 0.9 16.1 3962 0.9MACDONALD RIVER 24093.64 8706.36 17.3 5056 0.9 16.1 3961 0.9MACDONALD RIVER 23998.18 8801.82 17.3 5055 1.0 16.1 3960 0.9MACDONALD RIVER 23902.73 8897.27 17.3 5054 1.0 16.1 3960 0.9MACDONALD RIVER 23807.27 8992.73 17.2 5053 1.1 16.1 3959 1.0MACDONALD RIVER 23711.82 9088.18 17.2 5052 1.2 16.1 3958 1.1MACDONALD RIVER 23616.36 9183.64 17.2 5052 1.3 16.1 3958 1.2MACDONALD RIVER 23520.91 9279.09 17.2 5052 1.4 16.0 3957 1.3MACDONALD RIVER 23425.45 9374.55 17.1 5051 1.6 16.0 3957 1.5MACDONALD RIVER 23330 9470 17.1 5063 1.7 15.9 3965 1.6MACDONALD RIVER 23237 9563 17.0 5074 1.8 15.9 3974 1.6MACDONALD RIVER 23144 9656 17.0 5074 1.8 15.9 3973 1.6MACDONALD RIVER 23051 9749 17.0 5073 1.8 15.8 3973 1.6
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 22958 9842 17.0 5073 1.8 15.8 3973 1.6MACDONALD RIVER 22865 9935 16.9 5073 1.8 15.8 3972 1.7MACDONALD RIVER 22772 10028 16.9 5073 1.8 15.8 3972 1.7MACDONALD RIVER 22679 10121 16.9 5072 1.8 15.7 3972 1.7MACDONALD RIVER 22586 10214 16.8 5072 1.8 15.7 3972 1.7MACDONALD RIVER 22493 10307 16.8 5072 1.8 15.7 3972 1.7MACDONALD RIVER 22400 10400 16.8 5072 1.9 15.6 3971 1.7MACDONALD RIVER 22328.33 10471.67 16.7 5071 1.9 15.6 3971 1.7MACDONALD RIVER 22256.67 10543.33 16.7 5071 1.9 15.6 3971 1.8MACDONALD RIVER 22185 10615 16.7 5071 2.0 15.5 3971 1.8MACDONALD RIVER 22090 10710 16.6 5071 2.0 15.5 3971 1.8MACDONALD RIVER 21995 10805 16.6 5070 2.0 15.5 3970 1.8MACDONALD RIVER 21900 10900 16.6 5070 2.0 15.4 3970 1.9MACDONALD RIVER 21802.5 10997.5 16.5 5070 2.0 15.4 3970 1.9MACDONALD RIVER 21705 11095 16.5 5070 2.1 15.3 3970 1.9MACDONALD RIVER 21607.5 11192.5 16.4 5069 2.1 15.3 3969 1.9MACDONALD RIVER 21510 11290 16.4 5069 2.1 15.3 3969 2.0MACDONALD RIVER 21412.5 11387.5 16.4 5069 2.1 15.2 3969 2.0MACDONALD RIVER 21315 11485 16.3 5068 2.2 15.2 3969 2.0MACDONALD RIVER 21217.5 11582.5 16.3 5068 2.2 15.1 3968 2.0MACDONALD RIVER 21120 11680 16.2 5068 2.2 15.1 3968 2.1MACDONALD RIVER 21022.5 11777.5 16.2 5067 2.3 15.0 3968 2.1MACDONALD RIVER 20925 11875 16.1 5067 2.3 15.0 3968 2.1MACDONALD RIVER 20827.5 11972.5 16.0 5067 2.3 14.9 3968 2.1MACDONALD RIVER 20730 12070 16.0 5067 2.3 14.9 3967 2.2MACDONALD RIVER 20632.5 12167.5 15.9 5066 2.4 14.8 3967 2.2MACDONALD RIVER 20535 12265 15.9 5066 2.4 14.7 3967 2.2MACDONALD RIVER 20437.5 12362.5 15.8 5066 2.4 14.7 3967 2.2MACDONALD RIVER 20340 12460 15.8 5066 2.4 14.6 3967 2.2MACDONALD RIVER 20242.5 12557.5 15.7 5066 2.5 14.6 3967 2.3MACDONALD RIVER 20145 12655 15.6 5066 2.5 14.5 3967 2.3MACDONALD RIVER 20047.5 12752.5 15.6 5066 2.5 14.4 3967 2.3MACDONALD RIVER 19950 12850 15.5 5067 2.5 14.3 3968 2.4MACDONALD RIVER 19850.33 12949.67 15.4 5069 2.5 14.3 3969 2.3MACDONALD RIVER 19750.67 13049.33 15.4 5069 2.5 14.2 3969 2.3MACDONALD RIVER 19651 13149 15.3 5069 2.5 14.1 3969 2.3MACDONALD RIVER 19551.33 13248.67 15.2 5069 2.5 14.1 3968 2.3MACDONALD RIVER 19451.67 13348.33 15.2 5069 2.5 14.0 3968 2.3MACDONALD RIVER 19352 13448 15.1 5069 2.5 14.0 3968 2.3MACDONALD RIVER 19252.33 13547.67 15.1 5069 2.5 13.9 3968 2.3MACDONALD RIVER 19152.67 13647.33 15.0 5127 2.5 13.8 4013 2.3MACDONALD RIVER 19053 13747 14.9 5189 2.5 13.8 4060 2.3MACDONALD RIVER 18953.33 13846.67 14.9 5189 2.5 13.7 4059 2.3MACDONALD RIVER 18853.67 13946.33 14.8 5188 2.5 13.6 4059 2.3MACDONALD RIVER 18754 14046 14.8 5188 2.5 13.6 4059 2.3MACDONALD RIVER 18654.33 14145.67 14.7 5187 2.5 13.5 4058 2.3MACDONALD RIVER 18554.67 14245.33 14.6 5187 2.5 13.5 4058 2.3MACDONALD RIVER 18455 14345 14.6 5187 2.5 13.4 4058 2.3MACDONALD RIVER 18355.33 14444.67 14.5 5186 2.5 13.4 4057 2.3MACDONALD RIVER 18255.67 14544.33 14.5 5186 2.4 13.3 4057 2.2MACDONALD RIVER 18156 14644 14.4 5185 2.4 13.3 4057 2.2MACDONALD RIVER 18056.33 14743.67 14.4 5185 2.4 13.2 4056 2.2MACDONALD RIVER 17956.67 14843.33 14.3 5185 2.4 13.2 4056 2.2MACDONALD RIVER 17857 14943 14.3 5185 2.4 13.1 4056 2.2MACDONALD RIVER 17757.33 15042.67 14.2 5184 2.4 13.1 4056 2.2MACDONALD RIVER 17657.67 15142.33 14.2 5184 2.4 13.0 4056 2.2MACDONALD RIVER 17558 15242 14.1 5184 2.4 13.0 4056 2.1MACDONALD RIVER 17458.33 15341.67 14.1 5184 2.4 12.9 4055 2.1MACDONALD RIVER 17358.67 15441.33 14.0 5184 2.4 12.9 4055 2.1MACDONALD RIVER 17259 15541 14.0 5184 2.3 12.8 4055 2.1MACDONALD RIVER 17159.33 15640.67 13.9 5183 2.3 12.8 4055 2.1MACDONALD RIVER 17059.67 15740.33 13.9 5183 2.3 12.7 4054 2.1MACDONALD RIVER 16960 15840 13.8 5183 2.3 12.7 4054 2.1MACDONALD RIVER 16861.67 15938.33 13.8 5183 2.3 12.6 4054 2.0MACDONALD RIVER 16763.33 16036.67 13.7 5182 2.2 12.6 4054 2.0MACDONALD RIVER 16665 16135 13.7 5182 2.2 12.6 4053 2.0MACDONALD RIVER 16566.67 16233.33 13.7 5182 2.1 12.5 4053 1.9MACDONALD RIVER 16468.33 16331.67 13.6 5182 2.1 12.5 4053 1.9MACDONALD RIVER 16370 16430 13.6 5181 2.1 12.5 4053 1.9MACDONALD RIVER 16271.67 16528.33 13.6 5181 2.0 12.4 4052 1.8MACDONALD RIVER 16173.33 16626.67 13.5 5181 2.0 12.4 4052 1.8MACDONALD RIVER 16075 16725 13.5 5181 2.0 12.4 4052 1.8MACDONALD RIVER 15976.67 16823.33 13.5 5180 1.9 12.3 4052 1.7MACDONALD RIVER 15878.33 16921.67 13.4 5180 1.9 12.3 4051 1.7MACDONALD RIVER 15780 17020 13.4 5180 1.9 12.3 4051 1.7MACDONALD RIVER 15681.67 17118.33 13.4 5180 1.9 12.2 4051 1.7MACDONALD RIVER 15583.33 17216.67 13.3 5179 1.8 12.2 4050 1.6MACDONALD RIVER 15485 17315 13.3 5179 1.8 12.2 4050 1.6MACDONALD RIVER 15386.67 17413.33 13.3 5179 1.8 12.2 4050 1.6MACDONALD RIVER 15288.33 17511.67 13.3 5193 1.8 12.1 4060 1.6MACDONALD RIVER 15190 17610 13.2 5208 1.7 12.1 4071 1.6MACDONALD RIVER 15091.67 17708.33 13.2 5208 1.7 12.1 4071 1.5MACDONALD RIVER 14993.33 17806.67 13.2 5207 1.7 12.1 4070 1.5MACDONALD RIVER 14895 17905 13.2 5207 1.7 12.0 4070 1.5MACDONALD RIVER 14796.67 18003.33 13.1 5207 1.7 12.0 4069 1.5MACDONALD RIVER 14698.33 18101.67 13.1 5206 1.7 12.0 4069 1.5MACDONALD RIVER 14600 18200 13.1 5206 1.6 12.0 4069 1.5MACDONALD RIVER 14501.67 18298.33 13.1 5205 1.6 12.0 4069 1.4MACDONALD RIVER 14403.33 18396.67 13.0 5205 1.6 11.9 4068 1.4MACDONALD RIVER 14305 18495 13.0 5205 1.6 11.9 4068 1.4MACDONALD RIVER 14206.67 18593.33 13.0 5204 1.6 11.9 4068 1.4MACDONALD RIVER 14108.33 18691.67 13.0 5204 1.6 11.9 4068 1.4MACDONALD RIVER 14010 18790 12.9 5204 1.5 11.9 4068 1.4MACDONALD RIVER 13951.85 18848.15 12.9 5204 1.5 11.8 4068 1.4MACDONALD RIVER 13893.69 18906.31 12.9 5204 1.5 11.8 4067 1.3MACDONALD RIVER 13893.69 18906.31 12.9 5481 1.5 11.8 4279 1.3MACDONALD RIVER 13870 18930 12.9 5481 1.6 11.8 4279 1.4MACDONALD RIVER 13770.4 19029.6 12.9 5480 1.6 11.8 4279 1.4MACDONALD RIVER 13670.8 19129.2 12.9 5480 1.6 11.8 4278 1.4MACDONALD RIVER 13571.2 19228.8 12.8 5479 1.6 11.8 4278 1.4MACDONALD RIVER 13471.6 19328.4 12.8 5479 1.6 11.7 4277 1.4MACDONALD RIVER 13372 19428 12.8 5478 1.6 11.7 4277 1.4MACDONALD RIVER 13272.4 19527.6 12.8 5478 1.6 11.7 4276 1.4MACDONALD RIVER 13172.8 19627.2 12.7 5477 1.6 11.7 4276 1.4
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 13073.2 19726.8 12.7 5477 1.6 11.6 4275 1.5MACDONALD RIVER 12973.6 19826.4 12.7 5476 1.6 11.6 4275 1.5MACDONALD RIVER 12874 19926 12.7 5476 1.6 11.6 4274 1.5MACDONALD RIVER 12774.4 20025.6 12.6 5475 1.6 11.6 4274 1.5MACDONALD RIVER 12674.8 20125.2 12.6 5475 1.6 11.5 4273 1.5MACDONALD RIVER 12575.2 20224.8 12.6 5474 1.6 11.5 4273 1.5MACDONALD RIVER 12475.6 20324.4 12.6 5474 1.7 11.5 4272 1.5MACDONALD RIVER 12376 20424 12.5 5473 1.7 11.5 4272 1.5MACDONALD RIVER 12276.4 20523.6 12.5 5473 1.7 11.4 4271 1.5MACDONALD RIVER 12176.8 20623.2 12.5 5472 1.7 11.4 4271 1.5MACDONALD RIVER 12077.2 20722.8 12.4 5472 1.7 11.4 4271 1.5MACDONALD RIVER 11977.6 20822.4 12.4 5471 1.7 11.3 4271 1.5MACDONALD RIVER 11878 20922 12.4 5470 1.7 11.3 4270 1.5MACDONALD RIVER 11778.4 21021.6 12.3 5470 1.7 11.3 4270 1.5MACDONALD RIVER 11678.8 21121.2 12.3 5469 1.7 11.2 4270 1.5MACDONALD RIVER 11579.2 21220.8 12.3 5469 1.7 11.2 4269 1.5MACDONALD RIVER 11479.6 21320.4 12.2 5469 1.7 11.2 4269 1.6MACDONALD RIVER 11380 21420 12.2 5469 1.7 11.2 4269 1.6MACDONALD RIVER 11280.71 21519.29 12.2 5468 1.7 11.1 4268 1.6MACDONALD RIVER 11181.43 21618.57 12.1 5468 1.8 11.1 4268 1.6MACDONALD RIVER 11082.14 21717.86 12.1 5468 1.8 11.0 4268 1.6MACDONALD RIVER 10982.86 21817.14 12.1 5468 1.8 11.0 4267 1.6MACDONALD RIVER 10883.57 21916.43 12.0 5467 1.8 11.0 4267 1.6MACDONALD RIVER 10784.29 22015.71 12.0 5467 1.8 10.9 4267 1.6MACDONALD RIVER 10685 22115 11.9 5467 1.8 10.9 4266 1.6MACDONALD RIVER 10585.71 22214.29 11.9 5467 1.8 10.9 4266 1.6MACDONALD RIVER 10486.43 22313.57 11.9 5466 1.9 10.8 4266 1.7MACDONALD RIVER 10387.14 22412.86 11.8 5466 1.9 10.8 4265 1.7MACDONALD RIVER 10287.86 22512.14 11.8 5466 1.9 10.8 4265 1.7MACDONALD RIVER 10188.57 22611.43 11.7 5465 1.9 10.7 4265 1.7MACDONALD RIVER 10089.29 22710.71 11.7 5465 1.9 10.7 4264 1.7MACDONALD RIVER 9990 22810 11.6 5465 1.9 10.6 4264 1.7MACDONALD RIVER 9891.11 22908.89 11.6 5465 1.9 10.6 4264 1.7MACDONALD RIVER 9792.22 23007.78 11.6 5464 1.9 10.6 4264 1.7MACDONALD RIVER 9693.33 23106.67 11.5 5464 1.9 10.5 4264 1.7MACDONALD RIVER 9594.45 23205.55 11.5 5464 1.9 10.5 4264 1.7MACDONALD RIVER 9495.55 23304.45 11.4 5464 1.9 10.4 4264 1.7MACDONALD RIVER 9396.67 23403.33 11.4 5463 1.9 10.4 4263 1.7MACDONALD RIVER 9297.78 23502.22 11.4 5463 1.9 10.4 4263 1.7MACDONALD RIVER 9198.89 23601.11 11.3 5463 1.9 10.3 4263 1.7MACDONALD RIVER 9100 23700 11.3 5462 1.9 10.3 4263 1.7MACDONALD RIVER 9001.11 23798.89 11.2 5462 1.9 10.2 4263 1.7MACDONALD RIVER 8902.22 23897.78 11.2 5462 1.9 10.2 4263 1.7MACDONALD RIVER 8803.33 23996.67 11.1 5461 1.9 10.2 4262 1.7MACDONALD RIVER 8704.45 24095.55 11.1 5461 1.9 10.1 4262 1.7MACDONALD RIVER 8605.55 24194.45 11.1 5461 1.9 10.1 4262 1.7MACDONALD RIVER 8506.67 24293.33 11.0 5485 1.9 10.0 4279 1.7MACDONALD RIVER 8407.78 24392.22 11.0 5509 1.9 10.0 4296 1.7MACDONALD RIVER 8308.89 24491.11 10.9 5509 1.9 9.9 4296 1.7MACDONALD RIVER 8210 24590 10.9 5508 1.9 9.9 4296 1.7MACDONALD RIVER 8114.09 24685.91 10.8 5508 1.9 9.8 4296 1.8MACDONALD RIVER 8018.18 24781.82 10.8 5507 1.9 9.8 4295 1.8MACDONALD RIVER 7922.27 24877.73 10.7 5507 2.0 9.7 4295 1.8MACDONALD RIVER 7826.36 24973.64 10.7 5507 2.0 9.7 4295 1.8MACDONALD RIVER 7730.46 25069.54 10.6 5507 2.0 9.6 4295 1.8MACDONALD RIVER 7634.54 25165.46 10.6 5507 2.0 9.6 4294 1.8MACDONALD RIVER 7538.64 25261.36 10.5 5506 2.0 9.5 4294 1.8MACDONALD RIVER 7442.73 25357.27 10.4 5506 2.0 9.5 4294 1.8MACDONALD RIVER 7346.82 25453.18 10.4 5506 2.0 9.4 4294 1.8MACDONALD RIVER 7250.91 25549.09 10.3 5506 2.0 9.4 4293 1.8MACDONALD RIVER 7155 25645 10.3 5506 2.1 9.3 4293 1.9MACDONALD RIVER 7059.09 25740.91 10.2 5506 2.1 9.3 4293 1.9MACDONALD RIVER 6963.18 25836.82 10.2 5505 2.1 9.2 4293 1.9MACDONALD RIVER 6867.27 25932.73 10.1 5505 2.1 9.2 4292 1.9MACDONALD RIVER 6771.36 26028.64 10.1 5505 2.1 9.1 4292 1.9MACDONALD RIVER 6675.46 26124.54 10.0 5505 2.1 9.1 4292 1.9MACDONALD RIVER 6579.54 26220.46 10.0 5505 2.1 9.0 4292 1.9MACDONALD RIVER 6483.64 26316.36 9.9 5505 2.1 9.0 4292 1.9MACDONALD RIVER 6387.73 26412.27 9.9 5504 2.2 8.9 4292 1.9MACDONALD RIVER 6291.82 26508.18 9.8 5504 2.2 8.9 4292 1.9MACDONALD RIVER 6195.91 26604.09 9.7 5504 2.2 8.8 4292 1.9MACDONALD RIVER 6100 26700 9.7 5504 2.2 8.8 4292 1.9MACDONALD RIVER 6004.37 26795.63 9.6 5504 2.2 8.7 4291 1.9MACDONALD RIVER 5908.75 26891.25 9.6 5504 2.2 8.7 4291 1.9MACDONALD RIVER 5813.12 26986.88 9.5 5503 2.2 8.6 4291 1.9MACDONALD RIVER 5717.5 27082.5 9.5 5503 2.1 8.6 4291 1.9MACDONALD RIVER 5621.87 27178.13 9.5 5503 2.1 8.6 4291 1.9MACDONALD RIVER 5526.25 27273.75 9.5 5503 2.1 8.5 4291 1.9MACDONALD RIVER 5430.62 27369.38 9.5 5503 2.1 8.5 4291 1.9MACDONALD RIVER 5335 27465 9.5 5502 2.1 8.4 4291 1.9MACDONALD RIVER 5239.37 27560.63 9.5 5502 2.1 8.4 4291 1.8MACDONALD RIVER 5143.75 27656.25 9.5 5502 2.1 8.3 4290 1.8MACDONALD RIVER 5048.12 27751.88 9.5 5502 2.1 8.3 4290 1.8MACDONALD RIVER 4952.5 27847.5 9.5 5501 2.1 8.2 4290 1.8MACDONALD RIVER 4856.87 27943.13 9.5 5501 2.0 8.2 4290 1.8MACDONALD RIVER 4761.25 28038.75 9.5 5501 2.0 8.1 4290 1.8MACDONALD RIVER 4665.62 28134.38 9.5 5501 2.0 8.1 4290 1.8MACDONALD RIVER 4570 28230 9.5 5500 2.0 8.0 4290 1.8MACDONALD RIVER 4470.55 28329.45 9.5 5500 2.0 8.0 4290 1.8MACDONALD RIVER 4371.11 28428.89 9.5 5500 2.1 8.0 4289 1.8MACDONALD RIVER 4271.67 28528.33 9.5 5500 2.1 8.0 4289 1.8MACDONALD RIVER 4172.22 28627.78 9.5 5500 2.1 8.0 4289 1.8MACDONALD RIVER 4072.78 28727.22 9.5 5500 2.1 8.0 4289 1.9MACDONALD RIVER 3973.33 28826.67 9.5 5500 2.1 8.0 4289 1.9MACDONALD RIVER 3873.89 28926.11 9.5 5500 2.2 8.0 4289 1.9MACDONALD RIVER 3774.45 29025.55 9.5 5500 2.2 8.0 4289 1.9MACDONALD RIVER 3675 29125 9.5 5500 2.2 8.0 4289 2.0MACDONALD RIVER 3579.32 29220.68 9.5 5500 2.2 8.0 4289 1.9MACDONALD RIVER 3483.64 29316.36 9.5 5500 2.2 8.0 4289 1.9MACDONALD RIVER 3387.96 29412.04 9.5 5500 2.2 8.0 4289 1.9MACDONALD RIVER 3292.27 29507.73 9.5 5500 2.1 8.0 4289 1.9MACDONALD RIVER 3196.59 29603.41 9.5 5499 2.1 8.0 4289 1.9MACDONALD RIVER 3100.91 29699.09 9.5 5499 2.1 8.0 4289 1.9MACDONALD RIVER 3005.23 29794.77 9.5 5499 2.1 8.0 4289 1.9
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 2909.54 29890.46 9.5 5499 2.1 8.0 4289 1.8MACDONALD RIVER 2813.86 29986.14 9.5 5499 2.1 8.0 4289 1.8MACDONALD RIVER 2718.18 30081.82 9.5 5499 2.1 8.0 4289 1.8MACDONALD RIVER 2622.5 30177.5 9.5 5499 2.0 8.0 4289 1.8MACDONALD RIVER 2526.82 30273.18 9.5 5499 2.0 8.0 4289 1.8MACDONALD RIVER 2431.14 30368.86 9.5 5498 2.0 8.0 4289 1.8MACDONALD RIVER 2335.46 30464.54 9.5 5498 2.0 8.0 4289 1.8MACDONALD RIVER 2239.77 30560.23 9.5 5498 2.0 8.0 4289 1.8MACDONALD RIVER 2144.09 30655.91 9.5 5498 2.0 8.0 4289 1.8MACDONALD RIVER 2048.41 30751.59 9.5 5498 2.0 8.0 4289 1.7MACDONALD RIVER 1952.73 30847.27 9.5 5498 2.0 8.0 4289 1.7MACDONALD RIVER 1857.04 30942.96 9.5 5497 2.0 8.0 4289 1.7MACDONALD RIVER 1761.36 31038.64 9.5 5497 2.0 8.0 4289 1.7MACDONALD RIVER 1665.68 31134.32 9.5 5497 2.0 8.0 4289 1.7MACDONALD RIVER 1570 31230 9.5 5497 1.9 8.0 4289 1.7MACDONALD RIVER 1471.87 31328.13 9.5 5497 2.0 8.0 4289 1.7MACDONALD RIVER 1373.75 31426.25 9.5 5497 2.0 8.0 4289 1.8MACDONALD RIVER 1275.62 31524.38 9.5 5497 2.0 8.0 4289 1.8MACDONALD RIVER 1177.5 31622.5 9.5 5497 2.1 8.0 4289 1.8MACDONALD RIVER 1079.37 31720.63 9.5 5497 2.1 8.0 4289 1.8MACDONALD RIVER 981.25 31818.75 9.5 5497 2.2 8.0 4289 1.9MACDONALD RIVER 883.12 31916.88 9.5 5497 2.2 8.0 4289 1.9MACDONALD RIVER 785 32015 9.5 5497 2.3 8.0 4289 2.0MACDONALD RIVER 686.87 32113.13 9.5 5498 2.3 8.0 4289 2.0MACDONALD RIVER 588.75 32211.25 9.5 5498 2.4 8.0 4289 2.1MACDONALD RIVER 490.62 32309.38 9.5 5498 2.5 8.0 4289 2.1MACDONALD RIVER 392.5 32407.5 9.5 5498 2.6 8.0 4289 2.2MACDONALD RIVER 294.37 32505.63 9.5 5498 2.7 8.0 4290 2.3MACDONALD RIVER 196.25 32603.75 9.5 5498 2.9 8.0 4290 2.4MACDONALD RIVER 98.12 32701.88 9.5 5499 3.1 8.0 4290 2.5MACDONALD RIVER 0 32800 9.5 5499 3.5 8.0 4290 2.7
WRIGHTS CREEK 1410.78 0 12.9 566 0.3 11.8 465 0.3WRIGHTS CREEK 1313.86 96.92 12.9 557 0.3 11.8 460 0.3WRIGHTS CREEK 1216.93 193.85 12.9 547 0.3 11.8 455 0.3WRIGHTS CREEK 1120.01 290.77 12.9 538 0.3 11.8 450 0.3WRIGHTS CREEK 1023.09 387.69 12.9 529 0.3 11.8 444 0.3WRIGHTS CREEK 926.16 484.62 12.9 520 0.3 11.8 440 0.3WRIGHTS CREEK 829.24 581.54 12.9 511 0.3 11.8 435 0.3WRIGHTS CREEK 732.32 678.46 12.9 503 0.3 11.8 430 0.3WRIGHTS CREEK 635.4 775.38 12.9 494 0.3 11.8 425 0.3WRIGHTS CREEK 538.47 872.31 12.9 486 0.3 11.8 421 0.3WRIGHTS CREEK 441.55 969.23 12.9 478 0.3 11.8 416 0.3WRIGHTS CREEK 344.63 1066.15 12.9 470 0.3 11.8 412 0.3WRIGHTS CREEK 247.7 1163.08 12.9 463 0.3 11.8 408 0.3WRIGHTS CREEK 150.78 1260 12.9 455 0.3 11.8 404 0.3WRIGHTS CREEK 75.39 1335.39 12.9 449 0.3 11.8 401 0.3WRIGHTS CREEK 0 1410.78 12.9 444 0.3 11.8 397 0.3
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
River name Chainage from MIKE11 100 Year ARI 50 Year ARIHawkesbury River (m) Chainage (m) Flood Peak
(mAHD)Peak Discharge
(m3/s) Peak Velocity (m/s)Flood Peak
(mAHD)Peak Discharge
(m3/s) Peak Velocity (m/s)
MACDONALD RIVER 32800 0 17.7 2653 2.5 16.8 2051 2.5MACDONALD RIVER 32705 95 17.7 2653 2.4 16.7 2051 2.4MACDONALD RIVER 32610 190 17.6 2653 2.3 16.7 2051 2.3MACDONALD RIVER 32515 285 17.6 2653 2.3 16.6 2051 2.3MACDONALD RIVER 32420 380 17.6 2653 2.2 16.6 2051 2.2MACDONALD RIVER 32325 475 17.5 2653 2.1 16.5 2051 2.0MACDONALD RIVER 32230 570 17.5 2653 2.0 16.5 2050 1.9MACDONALD RIVER 32135 665 17.5 2653 2.0 16.5 2050 1.8MACDONALD RIVER 32040 760 17.4 2653 1.9 16.4 2050 1.8MACDONALD RIVER 31945 855 17.4 2653 1.9 16.4 2050 1.7MACDONALD RIVER 31850 950 17.4 2653 1.8 16.4 2050 1.7MACDONALD RIVER 31755 1045 17.4 2653 1.7 16.4 2050 1.6MACDONALD RIVER 31660 1140 17.3 2653 1.7 16.3 2050 1.6MACDONALD RIVER 31565 1235 17.3 2653 1.6 16.3 2050 1.5MACDONALD RIVER 31470 1330 17.3 2698 1.6 16.3 2085 1.5MACDONALD RIVER 31375 1425 17.3 2745 1.6 16.3 2120 1.5MACDONALD RIVER 31280 1520 17.2 2745 1.6 16.2 2120 1.4MACDONALD RIVER 31180.56 1619.44 17.2 2745 1.6 16.2 2119 1.4MACDONALD RIVER 31081.11 1718.89 17.2 2744 1.6 16.2 2119 1.4MACDONALD RIVER 30981.67 1818.33 17.2 2744 1.6 16.2 2119 1.5MACDONALD RIVER 30882.22 1917.78 17.1 2744 1.6 16.1 2119 1.5MACDONALD RIVER 30782.78 2017.22 17.1 2744 1.6 16.1 2119 1.5MACDONALD RIVER 30683.33 2116.67 17.1 2744 1.6 16.1 2119 1.5MACDONALD RIVER 30583.89 2216.11 17.0 2743 1.6 16.1 2119 1.5MACDONALD RIVER 30484.44 2315.56 17.0 2743 1.6 16.0 2118 1.5MACDONALD RIVER 30385 2415 17.0 2743 1.6 16.0 2118 1.5MACDONALD RIVER 30285.56 2514.44 16.9 2743 1.6 16.0 2118 1.5MACDONALD RIVER 30186.11 2613.89 16.9 2743 1.6 15.9 2118 1.5MACDONALD RIVER 30086.67 2713.33 16.9 2743 1.6 15.9 2118 1.5MACDONALD RIVER 29987.22 2812.78 16.9 2743 1.6 15.9 2118 1.5MACDONALD RIVER 29887.78 2912.22 16.8 2743 1.6 15.8 2118 1.5MACDONALD RIVER 29788.33 3011.67 16.8 2742 1.6 15.8 2117 1.5MACDONALD RIVER 29688.89 3111.11 16.7 2742 1.6 15.7 2117 1.6MACDONALD RIVER 29589.44 3210.56 16.7 2742 1.6 15.7 2117 1.6MACDONALD RIVER 29490 3310 16.7 2742 1.7 15.7 2117 1.6MACDONALD RIVER 29391.43 3408.57 16.6 2742 1.7 15.6 2117 1.6MACDONALD RIVER 29292.86 3507.14 16.6 2742 1.7 15.6 2117 1.6MACDONALD RIVER 29194.29 3605.71 16.6 2742 1.7 15.5 2117 1.6MACDONALD RIVER 29095.71 3704.29 16.5 2742 1.7 15.5 2117 1.6MACDONALD RIVER 28997.14 3802.86 16.5 2742 1.7 15.5 2117 1.6MACDONALD RIVER 28898.57 3901.43 16.4 2742 1.7 15.4 2117 1.6MACDONALD RIVER 28800 4000 16.4 2742 1.7 15.4 2117 1.6MACDONALD RIVER 28701.43 4098.57 16.4 2742 1.7 15.4 2117 1.6MACDONALD RIVER 28602.86 4197.14 16.3 2742 1.7 15.3 2117 1.6MACDONALD RIVER 28504.29 4295.71 16.3 2742 1.8 15.3 2117 1.6MACDONALD RIVER 28405.71 4394.29 16.2 2742 1.8 15.2 2117 1.6MACDONALD RIVER 28307.14 4492.86 16.2 2742 1.8 15.2 2117 1.6MACDONALD RIVER 28208.57 4591.43 16.1 2748 1.8 15.2 2122 1.6MACDONALD RIVER 28110 4690 16.1 2754 1.8 15.1 2126 1.6MACDONALD RIVER 28016.67 4783.33 16.1 2754 1.8 15.1 2126 1.6MACDONALD RIVER 27923.33 4876.67 16.0 2754 1.7 15.1 2126 1.6MACDONALD RIVER 27830 4970 16.0 2754 1.7 15.0 2126 1.5MACDONALD RIVER 27736.67 5063.33 16.0 2754 1.7 15.0 2126 1.5MACDONALD RIVER 27643.33 5156.67 16.0 2754 1.7 15.0 2126 1.5MACDONALD RIVER 27550 5250 15.9 2754 1.6 15.0 2126 1.5MACDONALD RIVER 27456.67 5343.33 15.9 2754 1.6 14.9 2126 1.5MACDONALD RIVER 27363.33 5436.67 15.9 2754 1.6 14.9 2126 1.4MACDONALD RIVER 27270 5530 15.9 2754 1.6 14.9 2126 1.4MACDONALD RIVER 27171 5629 15.8 2755 1.6 14.9 2126 1.4MACDONALD RIVER 27072 5728 15.8 2974 1.8 14.8 2296 1.6MACDONALD RIVER 26973 5827 15.7 3203 2.0 14.8 2473 1.8MACDONALD RIVER 26874 5926 15.6 3203 2.0 14.7 2473 1.8MACDONALD RIVER 26775 6025 15.6 3202 2.0 14.7 2472 1.9MACDONALD RIVER 26676 6124 15.6 3202 2.0 14.6 2472 1.9MACDONALD RIVER 26577 6223 15.5 3201 2.1 14.6 2472 2.0MACDONALD RIVER 26478 6322 15.5 3201 2.1 14.5 2471 2.1MACDONALD RIVER 26379 6421 15.4 3200 2.3 14.5 2471 2.3MACDONALD RIVER 26280 6520 15.4 3200 2.4 14.4 2471 2.5MACDONALD RIVER 26180 6620 15.3 3199 2.1 14.4 2470 2.1MACDONALD RIVER 26080 6720 15.3 3198 1.8 14.4 2470 1.8MACDONALD RIVER 25980 6820 15.3 3198 1.7 14.4 2469 1.6MACDONALD RIVER 25880 6920 15.3 3197 1.5 14.4 2469 1.4MACDONALD RIVER 25780 7020 15.3 3196 1.4 14.4 2468 1.3MACDONALD RIVER 25680 7120 15.3 3196 1.3 14.4 2468 1.2MACDONALD RIVER 25580 7220 15.3 3195 1.2 14.4 2467 1.1MACDONALD RIVER 25480 7320 15.3 3194 1.2 14.4 2466 1.0MACDONALD RIVER 25380 7420 15.3 3194 1.1 14.3 2466 1.0MACDONALD RIVER 25280 7520 15.3 3193 1.0 14.3 2465 0.9MACDONALD RIVER 25180 7620 15.3 3192 0.9 14.3 2464 0.8MACDONALD RIVER 25080 7720 15.3 3191 0.9 14.3 2464 0.9MACDONALD RIVER 24980 7820 15.3 3190 0.9 14.3 2463 0.9MACDONALD RIVER 24880 7920 15.3 3189 1.0 14.3 2462 1.0MACDONALD RIVER 24780 8020 15.3 3188 1.0 14.3 2462 1.1MACDONALD RIVER 24680 8120 15.3 3187 1.1 14.3 2461 1.2MACDONALD RIVER 24580 8220 15.3 3186 1.2 14.3 2460 1.3MACDONALD RIVER 24480 8320 15.3 3185 1.3 14.3 2460 1.5MACDONALD RIVER 24380 8420 15.3 3185 1.4 14.3 2459 1.7MACDONALD RIVER 24284.55 8515.45 15.3 3184 1.0 14.3 2458 1.0MACDONALD RIVER 24189.09 8610.91 15.2 3183 0.9 14.3 2457 0.9MACDONALD RIVER 24093.64 8706.36 15.2 3183 0.8 14.3 2457 0.9MACDONALD RIVER 23998.18 8801.82 15.2 3182 0.8 14.3 2457 0.9MACDONALD RIVER 23902.73 8897.27 15.2 3181 0.9 14.3 2456 0.9MACDONALD RIVER 23807.27 8992.73 15.2 3181 0.9 14.3 2456 0.9MACDONALD RIVER 23711.82 9088.18 15.2 3180 1.0 14.3 2456 1.0MACDONALD RIVER 23616.36 9183.64 15.2 3180 1.1 14.2 2455 1.0MACDONALD RIVER 23520.91 9279.09 15.1 3180 1.2 14.2 2455 1.1MACDONALD RIVER 23425.45 9374.55 15.1 3179 1.3 14.2 2455 1.2MACDONALD RIVER 23330 9470 15.0 3186 1.5 14.1 2459 1.5MACDONALD RIVER 23237 9563 15.0 3192 1.5 14.1 2464 1.4MACDONALD RIVER 23144 9656 15.0 3191 1.5 14.1 2463 1.4MACDONALD RIVER 23051 9749 15.0 3191 1.5 14.0 2463 1.4
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 22958 9842 14.9 3191 1.5 14.0 2463 1.4MACDONALD RIVER 22865 9935 14.9 3191 1.5 14.0 2463 1.4MACDONALD RIVER 22772 10028 14.9 3190 1.5 13.9 2462 1.4MACDONALD RIVER 22679 10121 14.8 3190 1.6 13.9 2462 1.4MACDONALD RIVER 22586 10214 14.8 3190 1.6 13.9 2462 1.4MACDONALD RIVER 22493 10307 14.8 3190 1.6 13.8 2462 1.5MACDONALD RIVER 22400 10400 14.7 3190 1.6 13.8 2462 1.5MACDONALD RIVER 22328.33 10471.67 14.7 3190 1.6 13.8 2461 1.5MACDONALD RIVER 22256.67 10543.33 14.7 3189 1.7 13.7 2461 1.5MACDONALD RIVER 22185 10615 14.6 3189 1.7 13.7 2461 1.6MACDONALD RIVER 22090 10710 14.6 3189 1.7 13.7 2461 1.6MACDONALD RIVER 21995 10805 14.6 3189 1.7 13.7 2461 1.6MACDONALD RIVER 21900 10900 14.5 3189 1.7 13.6 2461 1.6MACDONALD RIVER 21802.5 10997.5 14.5 3189 1.8 13.6 2461 1.6MACDONALD RIVER 21705 11095 14.5 3188 1.8 13.5 2461 1.7MACDONALD RIVER 21607.5 11192.5 14.4 3188 1.8 13.5 2461 1.7MACDONALD RIVER 21510 11290 14.4 3188 1.8 13.5 2461 1.7MACDONALD RIVER 21412.5 11387.5 14.3 3188 1.9 13.4 2460 1.7MACDONALD RIVER 21315 11485 14.3 3188 1.9 13.4 2460 1.7MACDONALD RIVER 21217.5 11582.5 14.2 3187 1.9 13.3 2460 1.8MACDONALD RIVER 21120 11680 14.2 3187 1.9 13.3 2460 1.8MACDONALD RIVER 21022.5 11777.5 14.1 3187 2.0 13.2 2460 1.8MACDONALD RIVER 20925 11875 14.1 3187 2.0 13.2 2460 1.8MACDONALD RIVER 20827.5 11972.5 14.0 3187 2.0 13.1 2460 1.8MACDONALD RIVER 20730 12070 14.0 3187 2.0 13.1 2460 1.9MACDONALD RIVER 20632.5 12167.5 13.9 3186 2.0 13.0 2460 1.9MACDONALD RIVER 20535 12265 13.9 3186 2.1 13.0 2459 1.9MACDONALD RIVER 20437.5 12362.5 13.8 3186 2.1 12.9 2459 1.9MACDONALD RIVER 20340 12460 13.7 3186 2.1 12.8 2459 1.9MACDONALD RIVER 20242.5 12557.5 13.7 3186 2.1 12.8 2459 2.0MACDONALD RIVER 20145 12655 13.6 3186 2.2 12.7 2459 2.0MACDONALD RIVER 20047.5 12752.5 13.5 3186 2.2 12.6 2459 2.0MACDONALD RIVER 19950 12850 13.5 3187 2.2 12.5 2459 2.1MACDONALD RIVER 19850.33 12949.67 13.4 3187 2.2 12.5 2460 2.0MACDONALD RIVER 19750.67 13049.33 13.3 3187 2.2 12.4 2460 2.0MACDONALD RIVER 19651 13149 13.2 3187 2.2 12.3 2460 2.0MACDONALD RIVER 19551.33 13248.67 13.2 3187 2.2 12.2 2460 2.0MACDONALD RIVER 19451.67 13348.33 13.1 3187 2.2 12.2 2460 2.0MACDONALD RIVER 19352 13448 13.0 3187 2.2 12.1 2460 2.0MACDONALD RIVER 19252.33 13547.67 13.0 3187 2.1 12.0 2459 2.0MACDONALD RIVER 19152.67 13647.33 12.9 3222 2.2 12.0 2485 2.0MACDONALD RIVER 19053 13747 12.8 3258 2.2 11.9 2512 2.0MACDONALD RIVER 18953.33 13846.67 12.8 3258 2.2 11.8 2512 2.0MACDONALD RIVER 18853.67 13946.33 12.7 3257 2.2 11.8 2512 2.0MACDONALD RIVER 18754 14046 12.7 3257 2.1 11.7 2511 2.0MACDONALD RIVER 18654.33 14145.67 12.6 3257 2.1 11.6 2511 2.0MACDONALD RIVER 18554.67 14245.33 12.6 3256 2.1 11.6 2511 1.9MACDONALD RIVER 18455 14345 12.5 3256 2.1 11.5 2511 1.9MACDONALD RIVER 18355.33 14444.67 12.4 3256 2.1 11.5 2510 1.9MACDONALD RIVER 18255.67 14544.33 12.4 3256 2.1 11.4 2510 1.9MACDONALD RIVER 18156 14644 12.3 3256 2.1 11.4 2510 1.9MACDONALD RIVER 18056.33 14743.67 12.3 3256 2.0 11.3 2510 1.9MACDONALD RIVER 17956.67 14843.33 12.3 3255 2.0 11.3 2510 1.8MACDONALD RIVER 17857 14943 12.2 3255 2.0 11.2 2509 1.8MACDONALD RIVER 17757.33 15042.67 12.2 3255 2.0 11.2 2509 1.8MACDONALD RIVER 17657.67 15142.33 12.1 3255 2.0 11.1 2509 1.8MACDONALD RIVER 17558 15242 12.1 3255 2.0 11.1 2509 1.8MACDONALD RIVER 17458.33 15341.67 12.0 3254 2.0 11.0 2509 1.8MACDONALD RIVER 17358.67 15441.33 12.0 3254 1.9 11.0 2509 1.8MACDONALD RIVER 17259 15541 11.9 3254 1.9 10.9 2508 1.7MACDONALD RIVER 17159.33 15640.67 11.9 3254 1.9 10.9 2508 1.7MACDONALD RIVER 17059.67 15740.33 11.8 3253 1.9 10.8 2508 1.7MACDONALD RIVER 16960 15840 11.8 3253 1.9 10.8 2508 1.7MACDONALD RIVER 16861.67 15938.33 11.7 3253 1.9 10.8 2508 1.7MACDONALD RIVER 16763.33 16036.67 11.7 3253 1.8 10.7 2507 1.6MACDONALD RIVER 16665 16135 11.7 3253 1.8 10.7 2507 1.6MACDONALD RIVER 16566.67 16233.33 11.6 3252 1.7 10.7 2507 1.6MACDONALD RIVER 16468.33 16331.67 11.6 3252 1.7 10.6 2507 1.5MACDONALD RIVER 16370 16430 11.6 3252 1.7 10.6 2507 1.5MACDONALD RIVER 16271.67 16528.33 11.5 3251 1.6 10.6 2506 1.5MACDONALD RIVER 16173.33 16626.67 11.5 3251 1.6 10.5 2506 1.4MACDONALD RIVER 16075 16725 11.5 3251 1.6 10.5 2506 1.4MACDONALD RIVER 15976.67 16823.33 11.4 3251 1.6 10.5 2506 1.4MACDONALD RIVER 15878.33 16921.67 11.4 3250 1.5 10.5 2505 1.4MACDONALD RIVER 15780 17020 11.4 3250 1.5 10.4 2505 1.3MACDONALD RIVER 15681.67 17118.33 11.4 3250 1.5 10.4 2505 1.3MACDONALD RIVER 15583.33 17216.67 11.3 3250 1.5 10.4 2505 1.3MACDONALD RIVER 15485 17315 11.3 3249 1.5 10.4 2504 1.3MACDONALD RIVER 15386.67 17413.33 11.3 3249 1.4 10.3 2504 1.3MACDONALD RIVER 15288.33 17511.67 11.3 3257 1.4 10.3 2509 1.3MACDONALD RIVER 15190 17610 11.2 3264 1.4 10.3 2515 1.2MACDONALD RIVER 15091.67 17708.33 11.2 3264 1.4 10.3 2515 1.2MACDONALD RIVER 14993.33 17806.67 11.2 3264 1.4 10.2 2514 1.2MACDONALD RIVER 14895 17905 11.2 3264 1.4 10.2 2514 1.2MACDONALD RIVER 14796.67 18003.33 11.1 3264 1.3 10.2 2514 1.2MACDONALD RIVER 14698.33 18101.67 11.1 3263 1.3 10.2 2514 1.2MACDONALD RIVER 14600 18200 11.1 3263 1.3 10.2 2514 1.2MACDONALD RIVER 14501.67 18298.33 11.1 3263 1.3 10.1 2513 1.2MACDONALD RIVER 14403.33 18396.67 11.1 3263 1.3 10.1 2513 1.2MACDONALD RIVER 14305 18495 11.0 3263 1.3 10.1 2513 1.1MACDONALD RIVER 14206.67 18593.33 11.0 3262 1.3 10.1 2513 1.1MACDONALD RIVER 14108.33 18691.67 11.0 3262 1.3 10.1 2513 1.1MACDONALD RIVER 14010 18790 11.0 3262 1.3 10.1 2512 1.1MACDONALD RIVER 13951.85 18848.15 11.0 3262 1.2 10.0 2512 1.1MACDONALD RIVER 13893.69 18906.31 11.0 3262 1.2 10.0 2512 1.1MACDONALD RIVER 13893.69 18906.31 11.0 3428 1.2 10.0 2636 1.1MACDONALD RIVER 13870 18930 11.0 3428 1.3 10.0 2636 1.1MACDONALD RIVER 13770.4 19029.6 10.9 3427 1.3 10.0 2635 1.1MACDONALD RIVER 13670.8 19129.2 10.9 3427 1.3 10.0 2635 1.1MACDONALD RIVER 13571.2 19228.8 10.9 3426 1.3 10.0 2634 1.1MACDONALD RIVER 13471.6 19328.4 10.9 3426 1.3 10.0 2634 1.1MACDONALD RIVER 13372 19428 10.9 3425 1.3 9.9 2634 1.1MACDONALD RIVER 13272.4 19527.6 10.8 3425 1.3 9.9 2633 1.2MACDONALD RIVER 13172.8 19627.2 10.8 3424 1.3 9.9 2633 1.2
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 13073.2 19726.8 10.8 3424 1.3 9.9 2633 1.2MACDONALD RIVER 12973.6 19826.4 10.8 3424 1.3 9.8 2632 1.2MACDONALD RIVER 12874 19926 10.7 3423 1.3 9.8 2632 1.2MACDONALD RIVER 12774.4 20025.6 10.7 3423 1.3 9.8 2632 1.2MACDONALD RIVER 12674.8 20125.2 10.7 3423 1.3 9.8 2632 1.2MACDONALD RIVER 12575.2 20224.8 10.7 3422 1.3 9.8 2631 1.2MACDONALD RIVER 12475.6 20324.4 10.6 3422 1.3 9.7 2631 1.2MACDONALD RIVER 12376 20424 10.6 3422 1.4 9.7 2631 1.2MACDONALD RIVER 12276.4 20523.6 10.6 3421 1.4 9.7 2630 1.2MACDONALD RIVER 12176.8 20623.2 10.6 3421 1.4 9.7 2630 1.2MACDONALD RIVER 12077.2 20722.8 10.5 3421 1.4 9.6 2630 1.2MACDONALD RIVER 11977.6 20822.4 10.5 3420 1.4 9.6 2629 1.2MACDONALD RIVER 11878 20922 10.5 3420 1.4 9.6 2629 1.2MACDONALD RIVER 11778.4 21021.6 10.4 3420 1.4 9.5 2629 1.2MACDONALD RIVER 11678.8 21121.2 10.4 3419 1.4 9.5 2628 1.3MACDONALD RIVER 11579.2 21220.8 10.4 3419 1.4 9.5 2628 1.3MACDONALD RIVER 11479.6 21320.4 10.4 3419 1.4 9.5 2628 1.3MACDONALD RIVER 11380 21420 10.3 3418 1.4 9.4 2628 1.3MACDONALD RIVER 11280.71 21519.29 10.3 3418 1.4 9.4 2628 1.3MACDONALD RIVER 11181.43 21618.57 10.3 3418 1.4 9.4 2627 1.3MACDONALD RIVER 11082.14 21717.86 10.2 3417 1.4 9.3 2627 1.3MACDONALD RIVER 10982.86 21817.14 10.2 3417 1.5 9.3 2627 1.3MACDONALD RIVER 10883.57 21916.43 10.2 3417 1.5 9.3 2627 1.3MACDONALD RIVER 10784.29 22015.71 10.1 3417 1.5 9.2 2627 1.3MACDONALD RIVER 10685 22115 10.1 3417 1.5 9.2 2626 1.3MACDONALD RIVER 10585.71 22214.29 10.1 3417 1.5 9.2 2626 1.3MACDONALD RIVER 10486.43 22313.57 10.0 3416 1.5 9.1 2626 1.3MACDONALD RIVER 10387.14 22412.86 10.0 3416 1.5 9.1 2626 1.4MACDONALD RIVER 10287.86 22512.14 9.9 3416 1.5 9.1 2626 1.4MACDONALD RIVER 10188.57 22611.43 9.9 3416 1.5 9.0 2626 1.4MACDONALD RIVER 10089.29 22710.71 9.9 3416 1.6 9.0 2625 1.4MACDONALD RIVER 9990 22810 9.8 3415 1.6 9.0 2625 1.4MACDONALD RIVER 9891.11 22908.89 9.8 3415 1.6 8.9 2625 1.4MACDONALD RIVER 9792.22 23007.78 9.8 3415 1.6 8.9 2625 1.4MACDONALD RIVER 9693.33 23106.67 9.7 3415 1.6 8.9 2624 1.4MACDONALD RIVER 9594.45 23205.55 9.7 3415 1.6 8.8 2624 1.4MACDONALD RIVER 9495.55 23304.45 9.7 3415 1.6 8.8 2624 1.4MACDONALD RIVER 9396.67 23403.33 9.6 3414 1.6 8.8 2624 1.4MACDONALD RIVER 9297.78 23502.22 9.6 3414 1.6 8.7 2624 1.4MACDONALD RIVER 9198.89 23601.11 9.5 3414 1.6 8.7 2624 1.4MACDONALD RIVER 9100 23700 9.5 3414 1.6 8.7 2624 1.4MACDONALD RIVER 9001.11 23798.89 9.5 3413 1.6 8.6 2624 1.4MACDONALD RIVER 8902.22 23897.78 9.4 3413 1.6 8.6 2624 1.4MACDONALD RIVER 8803.33 23996.67 9.4 3413 1.6 8.5 2623 1.4MACDONALD RIVER 8704.45 24095.55 9.3 3413 1.6 8.5 2623 1.4MACDONALD RIVER 8605.55 24194.45 9.3 3413 1.6 8.5 2623 1.4MACDONALD RIVER 8506.67 24293.33 9.3 3426 1.6 8.4 2632 1.4MACDONALD RIVER 8407.78 24392.22 9.2 3439 1.6 8.4 2641 1.4MACDONALD RIVER 8308.89 24491.11 9.2 3438 1.6 8.3 2641 1.5MACDONALD RIVER 8210 24590 9.1 3438 1.6 8.3 2641 1.5MACDONALD RIVER 8114.09 24685.91 9.1 3438 1.6 8.2 2641 1.5MACDONALD RIVER 8018.18 24781.82 9.0 3438 1.6 8.2 2640 1.5MACDONALD RIVER 7922.27 24877.73 9.0 3438 1.6 8.1 2640 1.5MACDONALD RIVER 7826.36 24973.64 8.9 3437 1.6 8.0 2640 1.5MACDONALD RIVER 7730.46 25069.54 8.9 3437 1.6 8.0 2640 1.5MACDONALD RIVER 7634.54 25165.46 8.8 3437 1.7 7.9 2640 1.5MACDONALD RIVER 7538.64 25261.36 8.8 3437 1.7 7.9 2639 1.5MACDONALD RIVER 7442.73 25357.27 8.7 3437 1.7 7.8 2639 1.5MACDONALD RIVER 7346.82 25453.18 8.7 3437 1.7 7.8 2639 1.5MACDONALD RIVER 7250.91 25549.09 8.6 3437 1.7 7.7 2639 1.5MACDONALD RIVER 7155 25645 8.6 3437 1.7 7.7 2639 1.5MACDONALD RIVER 7059.09 25740.91 8.5 3437 1.7 7.6 2638 1.5MACDONALD RIVER 6963.18 25836.82 8.5 3436 1.7 7.6 2638 1.6MACDONALD RIVER 6867.27 25932.73 8.4 3436 1.7 7.6 2638 1.6MACDONALD RIVER 6771.36 26028.64 8.4 3436 1.7 7.5 2638 1.6MACDONALD RIVER 6675.46 26124.54 8.3 3436 1.7 7.5 2638 1.6MACDONALD RIVER 6579.54 26220.46 8.3 3436 1.7 7.4 2638 1.6MACDONALD RIVER 6483.64 26316.36 8.2 3436 1.7 7.4 2638 1.6MACDONALD RIVER 6387.73 26412.27 8.2 3436 1.7 7.3 2638 1.6MACDONALD RIVER 6291.82 26508.18 8.2 3435 1.7 7.3 2638 1.6MACDONALD RIVER 6195.91 26604.09 8.1 3435 1.7 7.2 2637 1.6MACDONALD RIVER 6100 26700 8.1 3435 1.7 7.2 2637 1.6MACDONALD RIVER 6004.37 26795.63 8.0 3435 1.7 7.1 2637 1.5MACDONALD RIVER 5908.75 26891.25 8.0 3435 1.7 7.1 2637 1.5MACDONALD RIVER 5813.12 26986.88 7.9 3435 1.7 7.1 2637 1.5MACDONALD RIVER 5717.5 27082.5 7.9 3435 1.7 7.0 2637 1.5MACDONALD RIVER 5621.87 27178.13 7.8 3434 1.7 7.0 2637 1.5MACDONALD RIVER 5526.25 27273.75 7.8 3434 1.7 6.9 2637 1.5MACDONALD RIVER 5430.62 27369.38 7.8 3434 1.7 6.9 2637 1.5MACDONALD RIVER 5335 27465 7.7 3434 1.7 6.8 2636 1.5MACDONALD RIVER 5239.37 27560.63 7.7 3434 1.7 6.8 2636 1.5MACDONALD RIVER 5143.75 27656.25 7.6 3434 1.6 6.8 2636 1.5MACDONALD RIVER 5048.12 27751.88 7.6 3434 1.6 6.7 2636 1.5MACDONALD RIVER 4952.5 27847.5 7.6 3434 1.6 6.7 2636 1.5MACDONALD RIVER 4856.87 27943.13 7.5 3434 1.6 6.6 2636 1.5MACDONALD RIVER 4761.25 28038.75 7.5 3434 1.6 6.6 2636 1.5MACDONALD RIVER 4665.62 28134.38 7.4 3434 1.6 6.6 2635 1.5MACDONALD RIVER 4570 28230 7.4 3434 1.6 6.5 2635 1.5MACDONALD RIVER 4470.55 28329.45 7.3 3434 1.6 6.5 2635 1.5MACDONALD RIVER 4371.11 28428.89 7.3 3434 1.6 6.4 2635 1.5MACDONALD RIVER 4271.67 28528.33 7.2 3434 1.6 6.4 2635 1.5MACDONALD RIVER 4172.22 28627.78 7.2 3434 1.6 6.3 2635 1.5MACDONALD RIVER 4072.78 28727.22 7.2 3434 1.7 6.3 2635 1.5MACDONALD RIVER 3973.33 28826.67 7.1 3434 1.7 6.2 2635 1.5MACDONALD RIVER 3873.89 28926.11 7.0 3434 1.7 6.2 2635 1.5MACDONALD RIVER 3774.45 29025.55 7.0 3434 1.7 6.1 2635 1.5MACDONALD RIVER 3675 29125 6.9 3434 1.7 6.1 2635 1.6MACDONALD RIVER 3579.32 29220.68 6.9 3434 1.7 6.0 2635 1.5MACDONALD RIVER 3483.64 29316.36 6.8 3434 1.7 6.0 2635 1.5MACDONALD RIVER 3387.96 29412.04 6.8 3433 1.7 5.9 2635 1.5MACDONALD RIVER 3292.27 29507.73 6.8 3433 1.7 5.9 2635 1.5MACDONALD RIVER 3196.59 29603.41 6.7 3433 1.7 5.9 2635 1.5MACDONALD RIVER 3100.91 29699.09 6.7 3433 1.6 5.8 2634 1.5MACDONALD RIVER 3005.23 29794.77 6.7 3433 1.6 5.8 2634 1.5
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 2909.54 29890.46 6.7 3433 1.6 5.7 2634 1.5MACDONALD RIVER 2813.86 29986.14 6.7 3433 1.6 5.7 2634 1.5MACDONALD RIVER 2718.18 30081.82 6.7 3433 1.6 5.6 2634 1.5MACDONALD RIVER 2622.5 30177.5 6.7 3433 1.6 5.6 2634 1.5MACDONALD RIVER 2526.82 30273.18 6.7 3433 1.6 5.6 2634 1.5MACDONALD RIVER 2431.14 30368.86 6.7 3433 1.6 5.6 2634 1.4MACDONALD RIVER 2335.46 30464.54 6.7 3433 1.6 5.6 2634 1.4MACDONALD RIVER 2239.77 30560.23 6.7 3433 1.6 5.6 2634 1.4MACDONALD RIVER 2144.09 30655.91 6.7 3433 1.5 5.6 2634 1.4MACDONALD RIVER 2048.41 30751.59 6.7 3434 1.5 5.6 2634 1.4MACDONALD RIVER 1952.73 30847.27 6.7 3434 1.5 5.6 2634 1.4MACDONALD RIVER 1857.04 30942.96 6.7 3434 1.5 5.6 2634 1.4MACDONALD RIVER 1761.36 31038.64 6.7 3434 1.5 5.6 2634 1.4MACDONALD RIVER 1665.68 31134.32 6.7 3434 1.5 5.6 2634 1.4MACDONALD RIVER 1570 31230 6.7 3434 1.5 5.6 2634 1.5MACDONALD RIVER 1471.87 31328.13 6.7 3434 1.5 5.6 2634 1.5MACDONALD RIVER 1373.75 31426.25 6.7 3434 1.5 5.6 2634 1.5MACDONALD RIVER 1275.62 31524.38 6.7 3434 1.6 5.6 2634 1.5MACDONALD RIVER 1177.5 31622.5 6.7 3434 1.6 5.6 2634 1.6MACDONALD RIVER 1079.37 31720.63 6.7 3435 1.6 5.6 2634 1.6MACDONALD RIVER 981.25 31818.75 6.7 3435 1.6 5.6 2633 1.7MACDONALD RIVER 883.12 31916.88 6.7 3435 1.7 5.6 2633 1.7MACDONALD RIVER 785 32015 6.7 3435 1.7 5.6 2633 1.8MACDONALD RIVER 686.87 32113.13 6.7 3435 1.7 5.6 2633 1.9MACDONALD RIVER 588.75 32211.25 6.7 3435 1.8 5.6 2633 1.9MACDONALD RIVER 490.62 32309.38 6.7 3435 1.8 5.6 2633 2.0MACDONALD RIVER 392.5 32407.5 6.7 3436 1.9 5.6 2633 2.2MACDONALD RIVER 294.37 32505.63 6.7 3436 1.9 5.6 2633 2.4MACDONALD RIVER 196.25 32603.75 6.7 3436 2.0 5.6 2633 2.8MACDONALD RIVER 98.12 32701.88 6.7 3436 2.1 5.6 2633 3.7MACDONALD RIVER 0 32800 6.7 3437 2.2 5.6 2633 6.1
WRIGHTS CREEK 1410.78 0 11.0 392 0.3 10.0 323 0.5WRIGHTS CREEK 1313.86 96.92 11.0 386 0.3 10.0 314 0.5WRIGHTS CREEK 1216.93 193.85 11.0 380 0.3 10.0 306 0.5WRIGHTS CREEK 1120.01 290.77 11.0 374 0.3 10.0 299 0.5WRIGHTS CREEK 1023.09 387.69 11.0 369 0.3 10.0 291 0.4WRIGHTS CREEK 926.16 484.62 11.0 363 0.3 10.0 284 0.4WRIGHTS CREEK 829.24 581.54 11.0 357 0.3 10.0 276 0.4WRIGHTS CREEK 732.32 678.46 11.0 352 0.3 10.0 269 0.3WRIGHTS CREEK 635.4 775.38 11.0 347 0.3 10.0 265 0.3WRIGHTS CREEK 538.47 872.31 11.0 342 0.3 10.0 260 0.3WRIGHTS CREEK 441.55 969.23 11.0 337 0.3 10.0 256 0.3WRIGHTS CREEK 344.63 1066.15 11.0 332 0.3 10.0 253 0.3WRIGHTS CREEK 247.7 1163.08 11.0 329 0.3 10.0 250 0.2WRIGHTS CREEK 150.78 1260 11.0 326 0.3 10.0 246 0.2WRIGHTS CREEK 75.39 1335.39 11.0 323 0.3 10.0 244 0.2WRIGHTS CREEK 0 1410.78 11.0 320 0.3 10.0 242 0.2
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
River name Chainage from MIKE11 20 Year ARI 10 Year ARIHawkesbury River (m) Chainage (m) Flood Peak
(mAHD)Peak Discharge
(m3/s) Peak Velocity (m/s)Flood Peak
(mAHD)Peak Discharge
(m3/s) Peak Velocity (m/s)
MACDONALD RIVER 32800 0 15.5 1431 2.2 14.3 947 2.0MACDONALD RIVER 32705 95 15.5 1431 2.1 14.3 947 1.9MACDONALD RIVER 32610 190 15.4 1431 2.0 14.2 947 1.8MACDONALD RIVER 32515 285 15.4 1431 1.9 14.2 947 1.8MACDONALD RIVER 32420 380 15.4 1431 1.8 14.1 947 1.7MACDONALD RIVER 32325 475 15.3 1431 1.7 14.1 947 1.6MACDONALD RIVER 32230 570 15.3 1431 1.7 14.1 947 1.5MACDONALD RIVER 32135 665 15.3 1431 1.6 14.0 947 1.5MACDONALD RIVER 32040 760 15.2 1431 1.5 14.0 947 1.4MACDONALD RIVER 31945 855 15.2 1431 1.5 14.0 947 1.4MACDONALD RIVER 31850 950 15.2 1431 1.4 13.9 947 1.3MACDONALD RIVER 31755 1045 15.2 1431 1.4 13.9 946 1.3MACDONALD RIVER 31660 1140 15.1 1431 1.3 13.9 946 1.2MACDONALD RIVER 31565 1235 15.1 1430 1.3 13.9 946 1.2MACDONALD RIVER 31470 1330 15.1 1454 1.3 13.9 962 1.2MACDONALD RIVER 31375 1425 15.1 1477 1.3 13.8 978 1.2MACDONALD RIVER 31280 1520 15.0 1477 1.2 13.8 977 1.2MACDONALD RIVER 31180.56 1619.44 15.0 1477 1.3 13.8 977 1.2MACDONALD RIVER 31081.11 1718.89 15.0 1477 1.3 13.8 977 1.2MACDONALD RIVER 30981.67 1818.33 15.0 1476 1.3 13.7 977 1.2MACDONALD RIVER 30882.22 1917.78 14.9 1476 1.3 13.7 977 1.2MACDONALD RIVER 30782.78 2017.22 14.9 1476 1.3 13.7 976 1.2MACDONALD RIVER 30683.33 2116.67 14.9 1476 1.3 13.7 976 1.2MACDONALD RIVER 30583.89 2216.11 14.9 1476 1.3 13.6 976 1.2MACDONALD RIVER 30484.44 2315.56 14.8 1476 1.3 13.6 976 1.2MACDONALD RIVER 30385 2415 14.8 1476 1.4 13.6 976 1.2MACDONALD RIVER 30285.56 2514.44 14.8 1476 1.4 13.5 976 1.3MACDONALD RIVER 30186.11 2613.89 14.7 1476 1.4 13.5 975 1.3MACDONALD RIVER 30086.67 2713.33 14.7 1476 1.4 13.5 975 1.3MACDONALD RIVER 29987.22 2812.78 14.6 1475 1.4 13.4 975 1.4MACDONALD RIVER 29887.78 2912.22 14.6 1475 1.4 13.4 975 1.4MACDONALD RIVER 29788.33 3011.67 14.6 1475 1.5 13.3 975 1.4MACDONALD RIVER 29688.89 3111.11 14.5 1475 1.5 13.3 975 1.5MACDONALD RIVER 29589.44 3210.56 14.5 1475 1.5 13.2 974 1.5MACDONALD RIVER 29490 3310 14.4 1475 1.6 13.2 974 1.6MACDONALD RIVER 29391.43 3408.57 14.4 1475 1.6 13.2 974 1.6MACDONALD RIVER 29292.86 3507.14 14.3 1475 1.5 13.1 974 1.6MACDONALD RIVER 29194.29 3605.71 14.3 1475 1.5 13.1 974 1.5MACDONALD RIVER 29095.71 3704.29 14.3 1475 1.5 13.0 974 1.5MACDONALD RIVER 28997.14 3802.86 14.2 1475 1.5 13.0 974 1.5MACDONALD RIVER 28898.57 3901.43 14.2 1475 1.4 13.0 973 1.5MACDONALD RIVER 28800 4000 14.2 1475 1.4 12.9 973 1.5MACDONALD RIVER 28701.43 4098.57 14.1 1475 1.4 12.9 973 1.4MACDONALD RIVER 28602.86 4197.14 14.1 1475 1.4 12.9 973 1.4MACDONALD RIVER 28504.29 4295.71 14.1 1475 1.4 12.8 973 1.4MACDONALD RIVER 28405.71 4394.29 14.0 1475 1.4 12.8 973 1.4MACDONALD RIVER 28307.14 4492.86 14.0 1475 1.4 12.8 973 1.4MACDONALD RIVER 28208.57 4591.43 14.0 1477 1.4 12.8 974 1.4MACDONALD RIVER 28110 4690 13.9 1480 1.4 12.7 976 1.4MACDONALD RIVER 28016.67 4783.33 13.9 1480 1.3 12.7 976 1.3MACDONALD RIVER 27923.33 4876.67 13.9 1480 1.3 12.7 976 1.2MACDONALD RIVER 27830 4970 13.9 1480 1.3 12.7 976 1.2MACDONALD RIVER 27736.67 5063.33 13.8 1480 1.3 12.7 976 1.1MACDONALD RIVER 27643.33 5156.67 13.8 1480 1.3 12.7 975 1.1MACDONALD RIVER 27550 5250 13.8 1480 1.3 12.6 975 1.1MACDONALD RIVER 27456.67 5343.33 13.8 1480 1.3 12.6 975 1.1MACDONALD RIVER 27363.33 5436.67 13.8 1480 1.2 12.6 975 1.0MACDONALD RIVER 27270 5530 13.8 1480 1.2 12.6 975 1.0MACDONALD RIVER 27171 5629 13.7 1480 1.2 12.6 975 1.0MACDONALD RIVER 27072 5728 13.7 1598 1.3 12.5 1056 1.2MACDONALD RIVER 26973 5827 13.6 1720 1.6 12.5 1139 1.5MACDONALD RIVER 26874 5926 13.6 1720 1.7 12.5 1139 1.6MACDONALD RIVER 26775 6025 13.6 1719 1.7 12.4 1138 1.6MACDONALD RIVER 26676 6124 13.5 1719 1.8 12.4 1138 1.7MACDONALD RIVER 26577 6223 13.5 1719 1.9 12.4 1137 1.7MACDONALD RIVER 26478 6322 13.4 1718 2.0 12.3 1137 1.8MACDONALD RIVER 26379 6421 13.4 1718 2.1 12.3 1137 2.1MACDONALD RIVER 26280 6520 13.3 1718 2.6 12.2 1136 2.7MACDONALD RIVER 26180 6620 13.3 1718 2.2 12.2 1136 2.2MACDONALD RIVER 26080 6720 13.3 1717 1.9 12.2 1135 1.8MACDONALD RIVER 25980 6820 13.3 1717 1.7 12.2 1135 1.6MACDONALD RIVER 25880 6920 13.3 1717 1.5 12.2 1134 1.4MACDONALD RIVER 25780 7020 13.3 1716 1.3 12.2 1134 1.3MACDONALD RIVER 25680 7120 13.2 1716 1.2 12.2 1133 1.1MACDONALD RIVER 25580 7220 13.2 1715 1.1 12.2 1133 1.1MACDONALD RIVER 25480 7320 13.2 1715 1.0 12.1 1132 1.0MACDONALD RIVER 25380 7420 13.2 1714 1.0 12.1 1131 0.9MACDONALD RIVER 25280 7520 13.2 1713 0.9 12.1 1131 0.8MACDONALD RIVER 25180 7620 13.2 1713 0.9 12.1 1130 0.8MACDONALD RIVER 25080 7720 13.2 1712 0.8 12.1 1129 0.9MACDONALD RIVER 24980 7820 13.2 1712 0.9 12.1 1129 0.9MACDONALD RIVER 24880 7920 13.2 1711 1.0 12.1 1128 1.0MACDONALD RIVER 24780 8020 13.2 1711 1.1 12.1 1127 1.1MACDONALD RIVER 24680 8120 13.2 1710 1.2 12.1 1126 1.2MACDONALD RIVER 24580 8220 13.2 1710 1.3 12.1 1126 1.3MACDONALD RIVER 24480 8320 13.2 1709 1.5 12.1 1125 1.5MACDONALD RIVER 24380 8420 13.2 1708 1.7 12.1 1124 1.8MACDONALD RIVER 24284.55 8515.45 13.2 1708 1.1 12.1 1124 1.2MACDONALD RIVER 24189.09 8610.91 13.2 1707 1.0 12.1 1123 1.0MACDONALD RIVER 24093.64 8706.36 13.2 1707 0.9 12.1 1123 1.0MACDONALD RIVER 23998.18 8801.82 13.2 1707 0.9 12.1 1123 1.0MACDONALD RIVER 23902.73 8897.27 13.2 1706 1.0 12.1 1122 1.0MACDONALD RIVER 23807.27 8992.73 13.2 1706 1.0 12.1 1122 1.0MACDONALD RIVER 23711.82 9088.18 13.1 1706 1.0 12.1 1122 1.0MACDONALD RIVER 23616.36 9183.64 13.1 1706 1.0 12.1 1122 1.0MACDONALD RIVER 23520.91 9279.09 13.1 1705 1.1 12.0 1121 1.1MACDONALD RIVER 23425.45 9374.55 13.1 1705 1.1 12.0 1121 1.1MACDONALD RIVER 23330 9470 13.0 1708 1.6 12.0 1123 1.6MACDONALD RIVER 23237 9563 13.0 1710 1.3 11.9 1124 1.2MACDONALD RIVER 23144 9656 13.0 1710 1.3 11.9 1124 1.2MACDONALD RIVER 23051 9749 12.9 1710 1.3 11.9 1124 1.2
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 22958 9842 12.9 1710 1.3 11.8 1124 1.2MACDONALD RIVER 22865 9935 12.9 1710 1.3 11.8 1124 1.2MACDONALD RIVER 22772 10028 12.8 1710 1.3 11.8 1124 1.2MACDONALD RIVER 22679 10121 12.8 1710 1.3 11.8 1123 1.2MACDONALD RIVER 22586 10214 12.8 1710 1.3 11.7 1123 1.2MACDONALD RIVER 22493 10307 12.7 1709 1.3 11.7 1123 1.2MACDONALD RIVER 22400 10400 12.7 1709 1.3 11.7 1123 1.2MACDONALD RIVER 22328.33 10471.67 12.7 1709 1.3 11.7 1123 1.0MACDONALD RIVER 22256.67 10543.33 12.7 1709 1.3 11.6 1123 1.1MACDONALD RIVER 22185 10615 12.6 1709 1.4 11.6 1123 1.2MACDONALD RIVER 22090 10710 12.6 1709 1.4 11.6 1123 1.2MACDONALD RIVER 21995 10805 12.6 1709 1.4 11.6 1123 1.3MACDONALD RIVER 21900 10900 12.5 1709 1.5 11.5 1123 1.3MACDONALD RIVER 21802.5 10997.5 12.5 1709 1.5 11.5 1123 1.3MACDONALD RIVER 21705 11095 12.5 1709 1.5 11.5 1123 1.4MACDONALD RIVER 21607.5 11192.5 12.4 1708 1.5 11.5 1123 1.4MACDONALD RIVER 21510 11290 12.4 1708 1.5 11.4 1123 1.4MACDONALD RIVER 21412.5 11387.5 12.3 1708 1.5 11.4 1123 1.4MACDONALD RIVER 21315 11485 12.3 1708 1.5 11.4 1123 1.4MACDONALD RIVER 21217.5 11582.5 12.3 1708 1.5 11.3 1123 1.4MACDONALD RIVER 21120 11680 12.2 1708 1.6 11.3 1122 1.5MACDONALD RIVER 21022.5 11777.5 12.2 1708 1.6 11.3 1122 1.5MACDONALD RIVER 20925 11875 12.1 1708 1.6 11.2 1122 1.5MACDONALD RIVER 20827.5 11972.5 12.1 1708 1.6 11.2 1122 1.5MACDONALD RIVER 20730 12070 12.0 1708 1.6 11.1 1122 1.5MACDONALD RIVER 20632.5 12167.5 12.0 1708 1.6 11.1 1122 1.6MACDONALD RIVER 20535 12265 11.9 1708 1.7 11.0 1122 1.6MACDONALD RIVER 20437.5 12362.5 11.9 1708 1.7 11.0 1122 1.6MACDONALD RIVER 20340 12460 11.8 1708 1.7 10.9 1122 1.6MACDONALD RIVER 20242.5 12557.5 11.7 1708 1.7 10.8 1122 1.7MACDONALD RIVER 20145 12655 11.6 1708 1.8 10.7 1122 1.7MACDONALD RIVER 20047.5 12752.5 11.6 1708 1.8 10.7 1122 1.7MACDONALD RIVER 19950 12850 11.5 1708 1.8 10.6 1122 1.8MACDONALD RIVER 19850.33 12949.67 11.4 1708 1.8 10.5 1122 1.7MACDONALD RIVER 19750.67 13049.33 11.3 1708 1.8 10.4 1122 1.7MACDONALD RIVER 19651 13149 11.2 1708 1.8 10.3 1122 1.7MACDONALD RIVER 19551.33 13248.67 11.1 1708 1.8 10.2 1122 1.7MACDONALD RIVER 19451.67 13348.33 11.1 1708 1.8 10.1 1122 1.6MACDONALD RIVER 19352 13448 11.0 1707 1.8 10.0 1122 1.6MACDONALD RIVER 19252.33 13547.67 10.9 1707 1.8 9.9 1122 1.6MACDONALD RIVER 19152.67 13647.33 10.8 1724 1.8 9.9 1133 1.6MACDONALD RIVER 19053 13747 10.8 1742 1.8 9.8 1143 1.7MACDONALD RIVER 18953.33 13846.67 10.7 1741 1.8 9.7 1143 1.6MACDONALD RIVER 18853.67 13946.33 10.6 1741 1.8 9.6 1143 1.6MACDONALD RIVER 18754 14046 10.6 1741 1.8 9.5 1143 1.6MACDONALD RIVER 18654.33 14145.67 10.5 1741 1.7 9.5 1143 1.5MACDONALD RIVER 18554.67 14245.33 10.4 1741 1.7 9.4 1143 1.5MACDONALD RIVER 18455 14345 10.4 1741 1.7 9.3 1143 1.5MACDONALD RIVER 18355.33 14444.67 10.3 1741 1.7 9.3 1143 1.5MACDONALD RIVER 18255.67 14544.33 10.3 1740 1.7 9.2 1142 1.5MACDONALD RIVER 18156 14644 10.2 1740 1.7 9.1 1142 1.5MACDONALD RIVER 18056.33 14743.67 10.2 1740 1.6 9.1 1142 1.4MACDONALD RIVER 17956.67 14843.33 10.1 1740 1.6 9.0 1142 1.4MACDONALD RIVER 17857 14943 10.1 1740 1.6 9.0 1142 1.4MACDONALD RIVER 17757.33 15042.67 10.0 1739 1.6 8.9 1142 1.4MACDONALD RIVER 17657.67 15142.33 10.0 1739 1.6 8.9 1142 1.4MACDONALD RIVER 17558 15242 9.9 1739 1.6 8.8 1141 1.3MACDONALD RIVER 17458.33 15341.67 9.9 1739 1.5 8.8 1141 1.3MACDONALD RIVER 17358.67 15441.33 9.8 1739 1.5 8.7 1141 1.3MACDONALD RIVER 17259 15541 9.8 1738 1.5 8.7 1141 1.3MACDONALD RIVER 17159.33 15640.67 9.7 1738 1.5 8.6 1141 1.3MACDONALD RIVER 17059.67 15740.33 9.7 1738 1.5 8.6 1141 1.2MACDONALD RIVER 16960 15840 9.6 1738 1.5 8.6 1141 1.2MACDONALD RIVER 16861.67 15938.33 9.6 1738 1.4 8.5 1140 1.2MACDONALD RIVER 16763.33 16036.67 9.6 1738 1.4 8.5 1140 1.1MACDONALD RIVER 16665 16135 9.5 1737 1.3 8.5 1140 1.1MACDONALD RIVER 16566.67 16233.33 9.5 1737 1.3 8.4 1140 1.1MACDONALD RIVER 16468.33 16331.67 9.5 1737 1.3 8.4 1140 1.1MACDONALD RIVER 16370 16430 9.5 1737 1.3 8.4 1140 1.1MACDONALD RIVER 16271.67 16528.33 9.4 1736 1.2 8.4 1139 1.0MACDONALD RIVER 16173.33 16626.67 9.4 1736 1.2 8.3 1139 1.0MACDONALD RIVER 16075 16725 9.4 1736 1.2 8.3 1139 1.0MACDONALD RIVER 15976.67 16823.33 9.3 1736 1.2 8.3 1139 1.0MACDONALD RIVER 15878.33 16921.67 9.3 1736 1.1 8.2 1139 1.0MACDONALD RIVER 15780 17020 9.3 1735 1.1 8.2 1138 1.0MACDONALD RIVER 15681.67 17118.33 9.3 1735 1.1 8.2 1138 1.0MACDONALD RIVER 15583.33 17216.67 9.3 1735 1.1 8.2 1138 1.0MACDONALD RIVER 15485 17315 9.2 1735 1.1 8.2 1138 0.9MACDONALD RIVER 15386.67 17413.33 9.2 1734 1.1 8.1 1138 0.9MACDONALD RIVER 15288.33 17511.67 9.2 1738 1.1 8.1 1139 0.9MACDONALD RIVER 15190 17610 9.2 1741 1.1 8.1 1141 0.9MACDONALD RIVER 15091.67 17708.33 9.1 1741 1.0 8.1 1141 0.9MACDONALD RIVER 14993.33 17806.67 9.1 1740 1.0 8.1 1141 0.9MACDONALD RIVER 14895 17905 9.1 1740 1.0 8.0 1140 0.9MACDONALD RIVER 14796.67 18003.33 9.1 1740 1.0 8.0 1140 0.9MACDONALD RIVER 14698.33 18101.67 9.1 1740 1.0 8.0 1140 0.9MACDONALD RIVER 14600 18200 9.0 1739 1.0 8.0 1140 0.8MACDONALD RIVER 14501.67 18298.33 9.0 1739 1.0 8.0 1140 0.8MACDONALD RIVER 14403.33 18396.67 9.0 1739 1.0 8.0 1139 0.8MACDONALD RIVER 14305 18495 9.0 1739 1.0 7.9 1139 0.8MACDONALD RIVER 14206.67 18593.33 9.0 1738 1.0 7.9 1139 0.8MACDONALD RIVER 14108.33 18691.67 9.0 1738 0.9 7.9 1139 0.8MACDONALD RIVER 14010 18790 8.9 1738 0.9 7.9 1138 0.8MACDONALD RIVER 13951.85 18848.15 8.9 1738 0.9 7.9 1138 0.8MACDONALD RIVER 13893.69 18906.31 8.9 1738 0.9 7.9 1138 0.7MACDONALD RIVER 13893.69 18906.31 8.9 1819 0.9 7.9 1189 0.7MACDONALD RIVER 13870 18930 8.9 1819 0.9 7.9 1189 0.8MACDONALD RIVER 13770.4 19029.6 8.9 1819 0.9 7.9 1189 0.8MACDONALD RIVER 13670.8 19129.2 8.9 1818 0.9 7.8 1188 0.8MACDONALD RIVER 13571.2 19228.8 8.9 1818 0.9 7.8 1188 0.8MACDONALD RIVER 13471.6 19328.4 8.9 1818 1.0 7.8 1188 0.8MACDONALD RIVER 13372 19428 8.8 1818 1.0 7.8 1188 0.8MACDONALD RIVER 13272.4 19527.6 8.8 1817 1.0 7.8 1187 0.8MACDONALD RIVER 13172.8 19627.2 8.8 1817 1.0 7.8 1187 0.8
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 13073.2 19726.8 8.8 1817 1.0 7.8 1187 0.8MACDONALD RIVER 12973.6 19826.4 8.8 1816 1.0 7.7 1187 0.8MACDONALD RIVER 12874 19926 8.7 1816 1.0 7.7 1187 0.8MACDONALD RIVER 12774.4 20025.6 8.7 1816 1.0 7.7 1186 0.8MACDONALD RIVER 12674.8 20125.2 8.7 1816 1.0 7.7 1186 0.8MACDONALD RIVER 12575.2 20224.8 8.7 1816 1.0 7.7 1186 0.8MACDONALD RIVER 12475.6 20324.4 8.7 1815 1.0 7.6 1186 0.8MACDONALD RIVER 12376 20424 8.6 1815 1.0 7.6 1186 0.8MACDONALD RIVER 12276.4 20523.6 8.6 1815 1.0 7.6 1185 0.9MACDONALD RIVER 12176.8 20623.2 8.6 1815 1.0 7.6 1185 0.9MACDONALD RIVER 12077.2 20722.8 8.6 1814 1.0 7.6 1185 0.9MACDONALD RIVER 11977.6 20822.4 8.5 1814 1.1 7.5 1185 0.9MACDONALD RIVER 11878 20922 8.5 1814 1.1 7.5 1185 0.9MACDONALD RIVER 11778.4 21021.6 8.5 1814 1.1 7.5 1184 0.9MACDONALD RIVER 11678.8 21121.2 8.5 1813 1.1 7.5 1184 0.9MACDONALD RIVER 11579.2 21220.8 8.4 1813 1.1 7.4 1184 0.9MACDONALD RIVER 11479.6 21320.4 8.4 1813 1.1 7.4 1184 0.9MACDONALD RIVER 11380 21420 8.4 1813 1.1 7.4 1184 0.9MACDONALD RIVER 11280.71 21519.29 8.3 1813 1.1 7.3 1184 0.9MACDONALD RIVER 11181.43 21618.57 8.3 1812 1.1 7.3 1183 0.9MACDONALD RIVER 11082.14 21717.86 8.3 1812 1.1 7.3 1183 0.9MACDONALD RIVER 10982.86 21817.14 8.3 1812 1.1 7.3 1183 0.9MACDONALD RIVER 10883.57 21916.43 8.2 1812 1.1 7.2 1183 0.9MACDONALD RIVER 10784.29 22015.71 8.2 1812 1.1 7.2 1183 0.9MACDONALD RIVER 10685 22115 8.2 1812 1.1 7.2 1183 0.9MACDONALD RIVER 10585.71 22214.29 8.1 1811 1.1 7.2 1183 0.9MACDONALD RIVER 10486.43 22313.57 8.1 1811 1.1 7.1 1182 0.9MACDONALD RIVER 10387.14 22412.86 8.1 1811 1.1 7.1 1182 0.9MACDONALD RIVER 10287.86 22512.14 8.0 1811 1.1 7.1 1182 0.9MACDONALD RIVER 10188.57 22611.43 8.0 1811 1.2 7.0 1182 0.9MACDONALD RIVER 10089.29 22710.71 8.0 1811 1.2 7.0 1182 0.9MACDONALD RIVER 9990 22810 8.0 1810 1.2 7.0 1182 1.0MACDONALD RIVER 9891.11 22908.89 7.9 1810 1.2 7.0 1182 1.0MACDONALD RIVER 9792.22 23007.78 7.9 1810 1.2 6.9 1182 1.0MACDONALD RIVER 9693.33 23106.67 7.9 1810 1.2 6.9 1182 1.0MACDONALD RIVER 9594.45 23205.55 7.8 1810 1.2 6.9 1181 1.0MACDONALD RIVER 9495.55 23304.45 7.8 1810 1.2 6.9 1181 1.0MACDONALD RIVER 9396.67 23403.33 7.8 1810 1.2 6.8 1181 1.0MACDONALD RIVER 9297.78 23502.22 7.7 1810 1.2 6.8 1181 1.0MACDONALD RIVER 9198.89 23601.11 7.7 1810 1.2 6.8 1181 1.0MACDONALD RIVER 9100 23700 7.7 1809 1.2 6.7 1181 1.0MACDONALD RIVER 9001.11 23798.89 7.6 1809 1.2 6.7 1181 1.0MACDONALD RIVER 8902.22 23897.78 7.6 1809 1.2 6.7 1181 1.0MACDONALD RIVER 8803.33 23996.67 7.6 1809 1.2 6.6 1181 1.0MACDONALD RIVER 8704.45 24095.55 7.5 1809 1.2 6.6 1181 1.0MACDONALD RIVER 8605.55 24194.45 7.5 1809 1.2 6.5 1181 1.1MACDONALD RIVER 8506.67 24293.33 7.4 1814 1.2 6.5 1184 1.1MACDONALD RIVER 8407.78 24392.22 7.4 1820 1.3 6.4 1187 1.2MACDONALD RIVER 8308.89 24491.11 7.3 1820 1.3 6.4 1187 1.2MACDONALD RIVER 8210 24590 7.3 1820 1.3 6.3 1186 1.2MACDONALD RIVER 8114.09 24685.91 7.2 1820 1.3 6.2 1186 1.2MACDONALD RIVER 8018.18 24781.82 7.2 1819 1.3 6.2 1186 1.2MACDONALD RIVER 7922.27 24877.73 7.1 1819 1.3 6.1 1186 1.2MACDONALD RIVER 7826.36 24973.64 7.0 1819 1.3 6.0 1186 1.2MACDONALD RIVER 7730.46 25069.54 7.0 1819 1.3 6.0 1186 1.2MACDONALD RIVER 7634.54 25165.46 6.9 1819 1.4 5.9 1186 1.2MACDONALD RIVER 7538.64 25261.36 6.9 1819 1.4 5.9 1186 1.2MACDONALD RIVER 7442.73 25357.27 6.8 1819 1.4 5.8 1185 1.2MACDONALD RIVER 7346.82 25453.18 6.8 1818 1.4 5.8 1185 1.2MACDONALD RIVER 7250.91 25549.09 6.7 1818 1.4 5.7 1185 1.2MACDONALD RIVER 7155 25645 6.7 1818 1.4 5.7 1185 1.2MACDONALD RIVER 7059.09 25740.91 6.6 1818 1.4 5.6 1185 1.2MACDONALD RIVER 6963.18 25836.82 6.6 1818 1.4 5.6 1185 1.2MACDONALD RIVER 6867.27 25932.73 6.5 1818 1.4 5.5 1185 1.2MACDONALD RIVER 6771.36 26028.64 6.5 1818 1.4 5.5 1185 1.1MACDONALD RIVER 6675.46 26124.54 6.4 1818 1.4 5.4 1185 1.1MACDONALD RIVER 6579.54 26220.46 6.4 1817 1.4 5.4 1185 1.1MACDONALD RIVER 6483.64 26316.36 6.3 1817 1.3 5.4 1184 1.1MACDONALD RIVER 6387.73 26412.27 6.3 1817 1.3 5.3 1184 1.1MACDONALD RIVER 6291.82 26508.18 6.3 1817 1.3 5.3 1184 1.1MACDONALD RIVER 6195.91 26604.09 6.2 1817 1.3 5.3 1184 1.1MACDONALD RIVER 6100 26700 6.2 1817 1.3 5.2 1184 1.1MACDONALD RIVER 6004.37 26795.63 6.2 1817 1.3 5.2 1184 1.1MACDONALD RIVER 5908.75 26891.25 6.1 1817 1.3 5.2 1184 1.1MACDONALD RIVER 5813.12 26986.88 6.1 1817 1.3 5.1 1184 1.1MACDONALD RIVER 5717.5 27082.5 6.0 1816 1.3 5.1 1184 1.1MACDONALD RIVER 5621.87 27178.13 6.0 1816 1.3 5.1 1184 1.0MACDONALD RIVER 5526.25 27273.75 6.0 1816 1.3 5.0 1184 1.0MACDONALD RIVER 5430.62 27369.38 5.9 1816 1.3 5.0 1183 1.0MACDONALD RIVER 5335 27465 5.9 1816 1.3 5.0 1183 1.0MACDONALD RIVER 5239.37 27560.63 5.9 1816 1.3 4.9 1183 1.0MACDONALD RIVER 5143.75 27656.25 5.8 1816 1.3 4.9 1183 1.0MACDONALD RIVER 5048.12 27751.88 5.8 1816 1.2 4.9 1183 1.0MACDONALD RIVER 4952.5 27847.5 5.8 1816 1.2 4.8 1183 1.0MACDONALD RIVER 4856.87 27943.13 5.7 1816 1.2 4.8 1183 1.0MACDONALD RIVER 4761.25 28038.75 5.7 1816 1.2 4.8 1183 1.0MACDONALD RIVER 4665.62 28134.38 5.7 1816 1.2 4.8 1183 1.0MACDONALD RIVER 4570 28230 5.6 1815 1.2 4.7 1183 1.0MACDONALD RIVER 4470.55 28329.45 5.6 1815 1.2 4.7 1183 1.0MACDONALD RIVER 4371.11 28428.89 5.5 1815 1.2 4.7 1183 1.0MACDONALD RIVER 4271.67 28528.33 5.5 1815 1.2 4.6 1182 1.0MACDONALD RIVER 4172.22 28627.78 5.5 1815 1.2 4.6 1182 1.0MACDONALD RIVER 4072.78 28727.22 5.4 1815 1.3 4.6 1182 1.0MACDONALD RIVER 3973.33 28826.67 5.4 1815 1.3 4.5 1182 1.0MACDONALD RIVER 3873.89 28926.11 5.3 1815 1.3 4.5 1182 1.1MACDONALD RIVER 3774.45 29025.55 5.3 1815 1.3 4.4 1182 1.1MACDONALD RIVER 3675 29125 5.2 1815 1.3 4.4 1182 1.1MACDONALD RIVER 3579.32 29220.68 5.2 1815 1.3 4.4 1182 1.1MACDONALD RIVER 3483.64 29316.36 5.2 1815 1.3 4.3 1182 1.1MACDONALD RIVER 3387.96 29412.04 5.1 1815 1.3 4.3 1182 1.0MACDONALD RIVER 3292.27 29507.73 5.1 1814 1.3 4.3 1182 1.0MACDONALD RIVER 3196.59 29603.41 5.0 1814 1.3 4.2 1182 1.0MACDONALD RIVER 3100.91 29699.09 5.0 1814 1.2 4.2 1182 1.0MACDONALD RIVER 3005.23 29794.77 4.9 1814 1.2 4.1 1182 1.0
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 2909.54 29890.46 4.9 1814 1.2 4.1 1181 1.0MACDONALD RIVER 2813.86 29986.14 4.9 1814 1.2 4.1 1181 1.0MACDONALD RIVER 2718.18 30081.82 4.8 1814 1.2 4.0 1181 1.0MACDONALD RIVER 2622.5 30177.5 4.8 1814 1.2 4.0 1181 1.0MACDONALD RIVER 2526.82 30273.18 4.7 1814 1.2 3.9 1181 1.0MACDONALD RIVER 2431.14 30368.86 4.7 1814 1.2 3.9 1181 1.0MACDONALD RIVER 2335.46 30464.54 4.6 1814 1.2 3.9 1181 1.0MACDONALD RIVER 2239.77 30560.23 4.6 1814 1.2 3.9 1181 1.0MACDONALD RIVER 2144.09 30655.91 4.5 1814 1.2 3.9 1181 1.0MACDONALD RIVER 2048.41 30751.59 4.5 1814 1.2 3.9 1181 1.0MACDONALD RIVER 1952.73 30847.27 4.4 1814 1.2 3.9 1181 1.0MACDONALD RIVER 1857.04 30942.96 4.4 1814 1.2 3.9 1181 1.0MACDONALD RIVER 1761.36 31038.64 4.4 1814 1.2 3.9 1181 1.0MACDONALD RIVER 1665.68 31134.32 4.4 1814 1.2 3.9 1181 1.0MACDONALD RIVER 1570 31230 4.4 1814 1.2 3.9 1181 1.0MACDONALD RIVER 1471.87 31328.13 4.4 1814 1.3 3.9 1181 1.0MACDONALD RIVER 1373.75 31426.25 4.4 1813 1.3 3.9 1181 1.1MACDONALD RIVER 1275.62 31524.38 4.4 1813 1.3 3.9 1181 1.1MACDONALD RIVER 1177.5 31622.5 4.4 1813 1.3 3.9 1181 1.1MACDONALD RIVER 1079.37 31720.63 4.4 1813 1.4 3.9 1181 1.1MACDONALD RIVER 981.25 31818.75 4.4 1813 1.4 3.9 1181 1.2MACDONALD RIVER 883.12 31916.88 4.4 1813 1.4 3.9 1181 1.2MACDONALD RIVER 785 32015 4.4 1813 1.5 3.9 1181 1.2MACDONALD RIVER 686.87 32113.13 4.4 1813 1.6 3.9 1181 1.3MACDONALD RIVER 588.75 32211.25 4.4 1813 1.6 3.9 1181 1.3MACDONALD RIVER 490.62 32309.38 4.4 1813 1.7 3.9 1181 1.4MACDONALD RIVER 392.5 32407.5 4.4 1813 1.8 3.9 1181 1.5MACDONALD RIVER 294.37 32505.63 4.4 1813 2.0 3.9 1181 1.6MACDONALD RIVER 196.25 32603.75 4.4 1813 2.3 3.9 1181 1.8MACDONALD RIVER 98.12 32701.88 4.4 1813 3.0 3.9 1181 2.1MACDONALD RIVER 0 32800 4.4 1813 4.2 3.9 1181 2.7
WRIGHTS CREEK 1410.78 0 8.9 250 0.5 7.9 181 0.6WRIGHTS CREEK 1313.86 96.92 8.9 242 0.5 7.9 174 0.6WRIGHTS CREEK 1216.93 193.85 8.9 233 0.5 7.9 168 0.5WRIGHTS CREEK 1120.01 290.77 8.9 225 0.4 7.9 161 0.5WRIGHTS CREEK 1023.09 387.69 8.9 218 0.4 7.9 155 0.5WRIGHTS CREEK 926.16 484.62 8.9 210 0.4 7.9 148 0.4WRIGHTS CREEK 829.24 581.54 8.9 203 0.3 7.9 142 0.4WRIGHTS CREEK 732.32 678.46 8.9 197 0.3 7.9 136 0.4WRIGHTS CREEK 635.4 775.38 8.9 190 0.3 7.9 130 0.3WRIGHTS CREEK 538.47 872.31 8.9 184 0.3 7.9 125 0.3WRIGHTS CREEK 441.55 969.23 8.9 178 0.3 7.9 119 0.3WRIGHTS CREEK 344.63 1066.15 8.9 172 0.3 7.9 114 0.3WRIGHTS CREEK 247.7 1163.08 8.9 168 0.2 7.9 110 0.3WRIGHTS CREEK 150.78 1260 8.9 165 0.2 7.9 106 0.2WRIGHTS CREEK 75.39 1335.39 8.9 162 0.2 7.9 103 0.2WRIGHTS CREEK 0 1410.78 8.9 160 0.2 7.9 101 0.2
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
River name Chainage from MIKE11 5 Year ARI Extreme EventHawkesbury River (m) Chainage (m) Flood Peak
(mAHD)Peak Discharge
(m3/s) Peak Velocity (m/s)Flood Peak
(mAHD)Peak Discharge
(m3/s) Peak Velocity (m/s)
MACDONALD RIVER 32800 0 13.1 587 1.8 22.9 7960 3.8MACDONALD RIVER 32705 95 13.0 587 1.7 22.9 7960 3.6MACDONALD RIVER 32610 190 13.0 587 1.6 22.8 7960 3.5MACDONALD RIVER 32515 285 12.9 587 1.5 22.8 7960 3.4MACDONALD RIVER 32420 380 12.9 587 1.5 22.8 7959 3.3MACDONALD RIVER 32325 475 12.8 587 1.4 22.7 7959 3.2MACDONALD RIVER 32230 570 12.8 587 1.4 22.7 7959 3.1MACDONALD RIVER 32135 665 12.8 587 1.3 22.7 7959 3.0MACDONALD RIVER 32040 760 12.7 587 1.3 22.7 7959 2.9MACDONALD RIVER 31945 855 12.7 587 1.2 22.6 7958 2.8MACDONALD RIVER 31850 950 12.7 587 1.2 22.6 7958 2.7MACDONALD RIVER 31755 1045 12.6 587 1.1 22.6 7958 2.7MACDONALD RIVER 31660 1140 12.6 587 1.1 22.6 7958 2.6MACDONALD RIVER 31565 1235 12.6 587 1.0 22.6 7957 2.5MACDONALD RIVER 31470 1330 12.6 597 1.0 22.5 8020 2.5MACDONALD RIVER 31375 1425 12.5 608 1.1 22.5 8082 2.5MACDONALD RIVER 31280 1520 12.5 607 1.2 22.5 8082 2.4MACDONALD RIVER 31180.56 1619.44 12.5 607 1.1 22.4 8081 2.4MACDONALD RIVER 31081.11 1718.89 12.5 607 1.1 22.4 8081 2.4MACDONALD RIVER 30981.67 1818.33 12.4 607 1.1 22.4 8080 2.4MACDONALD RIVER 30882.22 1917.78 12.4 607 1.1 22.3 8080 2.4MACDONALD RIVER 30782.78 2017.22 12.4 607 1.1 22.3 8080 2.4MACDONALD RIVER 30683.33 2116.67 12.3 607 1.1 22.3 8079 2.4MACDONALD RIVER 30583.89 2216.11 12.3 607 1.1 22.3 8079 2.4MACDONALD RIVER 30484.44 2315.56 12.3 607 1.2 22.2 8079 2.4MACDONALD RIVER 30385 2415 12.2 607 1.2 22.2 8078 2.4MACDONALD RIVER 30285.56 2514.44 12.2 607 1.2 22.2 8078 2.4MACDONALD RIVER 30186.11 2613.89 12.2 607 1.2 22.1 8078 2.4MACDONALD RIVER 30086.67 2713.33 12.1 607 1.3 22.1 8077 2.4MACDONALD RIVER 29987.22 2812.78 12.1 607 1.3 22.0 8077 2.4MACDONALD RIVER 29887.78 2912.22 12.0 607 1.3 22.0 8077 2.4MACDONALD RIVER 29788.33 3011.67 12.0 607 1.4 22.0 8076 2.4MACDONALD RIVER 29688.89 3111.11 11.9 607 1.4 21.9 8076 2.4MACDONALD RIVER 29589.44 3210.56 11.9 606 1.5 21.9 8075 2.4MACDONALD RIVER 29490 3310 11.8 606 1.5 21.9 8075 2.4MACDONALD RIVER 29391.43 3408.57 11.7 606 1.5 21.8 8075 2.4MACDONALD RIVER 29292.86 3507.14 11.7 606 1.5 21.8 8074 2.4MACDONALD RIVER 29194.29 3605.71 11.6 606 1.5 21.8 8074 2.4MACDONALD RIVER 29095.71 3704.29 11.6 606 1.5 21.7 8074 2.4MACDONALD RIVER 28997.14 3802.86 11.5 606 1.5 21.7 8073 2.4MACDONALD RIVER 28898.57 3901.43 11.5 606 1.5 21.6 8073 2.5MACDONALD RIVER 28800 4000 11.4 606 1.5 21.6 8072 2.5MACDONALD RIVER 28701.43 4098.57 11.4 606 1.5 21.6 8072 2.5MACDONALD RIVER 28602.86 4197.14 11.3 606 1.5 21.5 8072 2.5MACDONALD RIVER 28504.29 4295.71 11.3 606 1.4 21.5 8071 2.5MACDONALD RIVER 28405.71 4394.29 11.2 606 1.4 21.4 8071 2.5MACDONALD RIVER 28307.14 4492.86 11.2 606 1.4 21.4 8070 2.5MACDONALD RIVER 28208.57 4591.43 11.2 607 1.4 21.3 8079 2.6MACDONALD RIVER 28110 4690 11.2 608 1.5 21.3 8087 2.6MACDONALD RIVER 28016.67 4783.33 11.1 608 1.3 21.2 8087 2.6MACDONALD RIVER 27923.33 4876.67 11.1 608 1.3 21.2 8086 2.5MACDONALD RIVER 27830 4970 11.1 608 1.2 21.2 8086 2.5MACDONALD RIVER 27736.67 5063.33 11.1 608 1.1 21.1 8085 2.5MACDONALD RIVER 27643.33 5156.67 11.0 608 1.1 21.1 8085 2.5MACDONALD RIVER 27550 5250 11.0 608 1.1 21.1 8085 2.5MACDONALD RIVER 27456.67 5343.33 11.0 608 1.0 21.0 8085 2.6MACDONALD RIVER 27363.33 5436.67 11.0 608 1.0 21.0 8085 2.6MACDONALD RIVER 27270 5530 11.0 608 1.0 20.9 8085 2.7MACDONALD RIVER 27171 5629 10.9 607 1.0 20.9 8084 2.7MACDONALD RIVER 27072 5728 10.9 662 1.1 20.8 8396 2.8MACDONALD RIVER 26973 5827 10.8 720 1.4 20.7 8713 3.0MACDONALD RIVER 26874 5926 10.8 720 1.4 20.6 8712 3.0MACDONALD RIVER 26775 6025 10.8 720 1.5 20.6 8711 3.0MACDONALD RIVER 26676 6124 10.7 719 1.5 20.5 8711 3.1MACDONALD RIVER 26577 6223 10.7 719 1.6 20.5 8710 3.1MACDONALD RIVER 26478 6322 10.6 719 1.8 20.4 8709 3.1MACDONALD RIVER 26379 6421 10.5 719 2.0 20.3 8708 3.2MACDONALD RIVER 26280 6520 10.5 718 2.5 20.3 8707 3.2MACDONALD RIVER 26180 6620 10.4 718 2.0 20.3 8706 2.9MACDONALD RIVER 26080 6720 10.4 718 1.6 20.3 8705 2.6MACDONALD RIVER 25980 6820 10.4 717 1.4 20.3 8704 2.4MACDONALD RIVER 25880 6920 10.4 717 1.2 20.3 8703 2.2MACDONALD RIVER 25780 7020 10.4 716 1.1 20.3 8702 2.0MACDONALD RIVER 25680 7120 10.4 716 1.0 20.4 8701 1.9MACDONALD RIVER 25580 7220 10.4 715 0.9 20.4 8700 1.7MACDONALD RIVER 25480 7320 10.3 714 0.8 20.4 8699 1.6MACDONALD RIVER 25380 7420 10.3 714 0.8 20.4 8697 1.5MACDONALD RIVER 25280 7520 10.3 713 0.7 20.4 8696 1.4MACDONALD RIVER 25180 7620 10.3 712 0.8 20.4 8695 1.3MACDONALD RIVER 25080 7720 10.3 712 0.9 20.4 8694 1.3MACDONALD RIVER 24980 7820 10.3 711 0.9 20.4 8692 1.2MACDONALD RIVER 24880 7920 10.3 710 1.0 20.4 8691 1.1MACDONALD RIVER 24780 8020 10.3 710 1.1 20.4 8689 1.1MACDONALD RIVER 24680 8120 10.3 709 1.2 20.4 8688 1.1MACDONALD RIVER 24580 8220 10.3 708 1.3 20.4 8686 1.2MACDONALD RIVER 24480 8320 10.3 707 1.5 20.4 8684 1.3MACDONALD RIVER 24380 8420 10.3 707 1.7 20.4 8682 1.4MACDONALD RIVER 24284.55 8515.45 10.3 706 1.2 20.3 8681 1.0MACDONALD RIVER 24189.09 8610.91 10.3 706 1.0 20.3 8679 1.0MACDONALD RIVER 24093.64 8706.36 10.3 705 0.9 20.3 8678 1.1MACDONALD RIVER 23998.18 8801.82 10.3 705 0.9 20.3 8677 1.2MACDONALD RIVER 23902.73 8897.27 10.2 705 0.9 20.3 8677 1.3MACDONALD RIVER 23807.27 8992.73 10.2 704 0.9 20.3 8676 1.4MACDONALD RIVER 23711.82 9088.18 10.2 704 1.0 20.2 8675 1.5MACDONALD RIVER 23616.36 9183.64 10.2 704 1.0 20.2 8675 1.6MACDONALD RIVER 23520.91 9279.09 10.1 704 1.0 20.2 8674 1.8MACDONALD RIVER 23425.45 9374.55 10.1 704 1.0 20.1 8674 1.9MACDONALD RIVER 23330 9470 10.1 705 1.5 20.0 8682 2.1MACDONALD RIVER 23237 9563 10.0 705 1.1 20.0 8690 2.1MACDONALD RIVER 23144 9656 10.0 705 1.1 20.0 8689 2.2MACDONALD RIVER 23051 9749 10.0 705 1.1 20.0 8689 2.2
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 22958 9842 10.0 705 1.1 19.9 8689 2.2MACDONALD RIVER 22865 9935 9.9 705 1.1 19.9 8688 2.2MACDONALD RIVER 22772 10028 9.9 705 1.1 19.9 8688 2.2MACDONALD RIVER 22679 10121 9.9 705 1.1 19.8 8687 2.2MACDONALD RIVER 22586 10214 9.9 705 1.1 19.8 8687 2.2MACDONALD RIVER 22493 10307 9.8 705 1.1 19.8 8686 2.3MACDONALD RIVER 22400 10400 9.8 705 1.1 19.7 8686 2.3MACDONALD RIVER 22328.33 10471.67 9.8 705 0.8 19.7 8686 2.3MACDONALD RIVER 22256.67 10543.33 9.8 705 0.9 19.7 8685 2.4MACDONALD RIVER 22185 10615 9.8 705 1.2 19.6 8685 2.4MACDONALD RIVER 22090 10710 9.8 705 1.2 19.6 8685 2.4MACDONALD RIVER 21995 10805 9.7 705 1.2 19.6 8684 2.4MACDONALD RIVER 21900 10900 9.7 705 1.3 19.5 8684 2.4MACDONALD RIVER 21802.5 10997.5 9.7 705 1.3 19.5 8683 2.5MACDONALD RIVER 21705 11095 9.7 705 1.3 19.4 8683 2.5MACDONALD RIVER 21607.5 11192.5 9.6 705 1.3 19.4 8682 2.5MACDONALD RIVER 21510 11290 9.6 704 1.4 19.4 8682 2.5MACDONALD RIVER 21412.5 11387.5 9.6 704 1.4 19.3 8681 2.6MACDONALD RIVER 21315 11485 9.5 704 1.4 19.3 8681 2.6MACDONALD RIVER 21217.5 11582.5 9.5 704 1.4 19.2 8680 2.6MACDONALD RIVER 21120 11680 9.5 704 1.4 19.2 8680 2.7MACDONALD RIVER 21022.5 11777.5 9.4 704 1.4 19.1 8679 2.7MACDONALD RIVER 20925 11875 9.4 704 1.5 19.0 8679 2.7MACDONALD RIVER 20827.5 11972.5 9.4 704 1.5 19.0 8679 2.7MACDONALD RIVER 20730 12070 9.3 704 1.5 18.9 8679 2.8MACDONALD RIVER 20632.5 12167.5 9.3 704 1.5 18.9 8679 2.8MACDONALD RIVER 20535 12265 9.2 704 1.5 18.8 8679 2.8MACDONALD RIVER 20437.5 12362.5 9.2 704 1.6 18.7 8678 2.9MACDONALD RIVER 20340 12460 9.1 704 1.6 18.7 8678 2.9MACDONALD RIVER 20242.5 12557.5 9.1 704 1.6 18.6 8678 2.9MACDONALD RIVER 20145 12655 9.0 704 1.6 18.5 8678 3.0MACDONALD RIVER 20047.5 12752.5 9.0 704 1.7 18.5 8678 3.0MACDONALD RIVER 19950 12850 8.9 704 1.7 18.4 8678 3.0MACDONALD RIVER 19850.33 12949.67 8.9 704 1.7 18.3 8679 3.0MACDONALD RIVER 19750.67 13049.33 8.8 704 1.7 18.3 8679 3.0MACDONALD RIVER 19651 13149 8.7 704 1.7 18.2 8678 3.0MACDONALD RIVER 19551.33 13248.67 8.7 704 1.6 18.1 8678 3.0MACDONALD RIVER 19451.67 13348.33 8.6 704 1.6 18.1 8678 3.0MACDONALD RIVER 19352 13448 8.6 704 1.6 18.0 8678 3.0MACDONALD RIVER 19252.33 13547.67 8.5 704 1.6 18.0 8678 3.0MACDONALD RIVER 19152.67 13647.33 8.5 711 1.6 17.9 8725 3.0MACDONALD RIVER 19053 13747 8.4 718 1.6 17.8 8773 3.0MACDONALD RIVER 18953.33 13846.67 8.4 718 1.5 17.8 8773 3.0MACDONALD RIVER 18853.67 13946.33 8.3 718 1.5 17.7 8772 3.0MACDONALD RIVER 18754 14046 8.3 718 1.5 17.6 8772 3.0MACDONALD RIVER 18654.33 14145.67 8.2 718 1.4 17.6 8771 3.0MACDONALD RIVER 18554.67 14245.33 8.2 718 1.4 17.5 8771 3.0MACDONALD RIVER 18455 14345 8.1 718 1.4 17.5 8771 3.0MACDONALD RIVER 18355.33 14444.67 8.1 718 1.4 17.4 8771 3.0MACDONALD RIVER 18255.67 14544.33 8.0 718 1.3 17.3 8770 3.0MACDONALD RIVER 18156 14644 8.0 718 1.3 17.3 8770 3.0MACDONALD RIVER 18056.33 14743.67 8.0 718 1.3 17.2 8770 3.0MACDONALD RIVER 17956.67 14843.33 7.9 718 1.2 17.2 8769 3.0MACDONALD RIVER 17857 14943 7.9 718 1.2 17.1 8769 3.0MACDONALD RIVER 17757.33 15042.67 7.9 718 1.2 17.1 8769 3.0MACDONALD RIVER 17657.67 15142.33 7.8 718 1.2 17.0 8768 3.0MACDONALD RIVER 17558 15242 7.8 718 1.1 16.9 8768 3.0MACDONALD RIVER 17458.33 15341.67 7.7 718 1.1 16.9 8768 3.0MACDONALD RIVER 17358.67 15441.33 7.7 718 1.1 16.8 8767 3.0MACDONALD RIVER 17259 15541 7.7 718 1.1 16.7 8767 2.9MACDONALD RIVER 17159.33 15640.67 7.6 717 1.0 16.7 8767 2.9MACDONALD RIVER 17059.67 15740.33 7.6 717 1.0 16.6 8766 2.9MACDONALD RIVER 16960 15840 7.6 717 1.0 16.6 8766 2.9MACDONALD RIVER 16861.67 15938.33 7.6 717 1.0 16.5 8765 2.9MACDONALD RIVER 16763.33 16036.67 7.5 717 1.0 16.5 8765 2.8MACDONALD RIVER 16665 16135 7.5 717 1.0 16.4 8765 2.8MACDONALD RIVER 16566.67 16233.33 7.5 717 1.0 16.4 8764 2.7MACDONALD RIVER 16468.33 16331.67 7.5 717 0.9 16.3 8764 2.7MACDONALD RIVER 16370 16430 7.4 717 0.9 16.3 8763 2.7MACDONALD RIVER 16271.67 16528.33 7.4 717 0.9 16.3 8763 2.6MACDONALD RIVER 16173.33 16626.67 7.4 717 0.9 16.3 8762 2.6MACDONALD RIVER 16075 16725 7.4 717 0.9 16.3 8762 2.5MACDONALD RIVER 15976.67 16823.33 7.3 717 0.9 16.3 8761 2.5MACDONALD RIVER 15878.33 16921.67 7.3 717 0.9 16.3 8761 2.5MACDONALD RIVER 15780 17020 7.3 717 0.8 16.3 8760 2.4MACDONALD RIVER 15681.67 17118.33 7.3 717 0.8 16.3 8760 2.4MACDONALD RIVER 15583.33 17216.67 7.2 717 0.8 16.3 8760 2.4MACDONALD RIVER 15485 17315 7.2 717 0.8 16.3 8759 2.3MACDONALD RIVER 15386.67 17413.33 7.2 716 0.8 16.3 8759 2.3MACDONALD RIVER 15288.33 17511.67 7.2 718 0.8 16.3 8769 2.3MACDONALD RIVER 15190 17610 7.2 719 0.8 16.3 8780 2.3MACDONALD RIVER 15091.67 17708.33 7.2 719 0.7 16.3 8780 2.2MACDONALD RIVER 14993.33 17806.67 7.1 719 0.7 16.3 8780 2.2MACDONALD RIVER 14895 17905 7.1 719 0.7 16.3 8779 2.2MACDONALD RIVER 14796.67 18003.33 7.1 719 0.7 16.3 8779 2.2MACDONALD RIVER 14698.33 18101.67 7.1 719 0.7 16.3 8779 2.1MACDONALD RIVER 14600 18200 7.1 718 0.7 16.3 8778 2.1MACDONALD RIVER 14501.67 18298.33 7.1 718 0.7 16.3 8778 2.1MACDONALD RIVER 14403.33 18396.67 7.0 718 0.7 16.3 8778 2.1MACDONALD RIVER 14305 18495 7.0 718 0.7 16.3 8777 2.1MACDONALD RIVER 14206.67 18593.33 7.0 718 0.6 16.3 8777 2.0MACDONALD RIVER 14108.33 18691.67 7.0 718 0.6 16.3 8777 2.0MACDONALD RIVER 14010 18790 7.0 718 0.6 16.3 8776 2.0MACDONALD RIVER 13951.85 18848.15 7.0 718 0.6 16.3 8776 2.0MACDONALD RIVER 13893.69 18906.31 7.0 718 0.6 16.3 8776 2.0MACDONALD RIVER 13893.69 18906.31 7.0 755 0.6 16.3 9003 2.0MACDONALD RIVER 13870 18930 7.0 754 0.6 16.3 9003 2.0MACDONALD RIVER 13770.4 19029.6 7.0 754 0.6 16.3 9002 2.0MACDONALD RIVER 13670.8 19129.2 6.9 754 0.6 16.3 9002 2.0MACDONALD RIVER 13571.2 19228.8 6.9 754 0.6 16.3 9002 2.0MACDONALD RIVER 13471.6 19328.4 6.9 754 0.7 16.3 9001 2.0MACDONALD RIVER 13372 19428 6.9 754 0.7 16.3 9001 2.0MACDONALD RIVER 13272.4 19527.6 6.9 754 0.7 16.3 9000 2.0MACDONALD RIVER 13172.8 19627.2 6.9 754 0.7 16.3 9000 2.0
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 13073.2 19726.8 6.9 754 0.7 16.3 9000 2.0MACDONALD RIVER 12973.6 19826.4 6.8 754 0.7 16.3 8999 2.0MACDONALD RIVER 12874 19926 6.8 753 0.7 16.3 8999 2.0MACDONALD RIVER 12774.4 20025.6 6.8 753 0.7 16.3 8999 2.0MACDONALD RIVER 12674.8 20125.2 6.8 753 0.7 16.3 8998 2.1MACDONALD RIVER 12575.2 20224.8 6.8 753 0.7 16.3 8998 2.1MACDONALD RIVER 12475.6 20324.4 6.8 753 0.7 16.3 8997 2.1MACDONALD RIVER 12376 20424 6.7 753 0.8 16.3 8997 2.1MACDONALD RIVER 12276.4 20523.6 6.7 753 0.8 16.3 8996 2.1MACDONALD RIVER 12176.8 20623.2 6.7 753 0.8 16.3 8996 2.1MACDONALD RIVER 12077.2 20722.8 6.7 753 0.8 16.3 8996 2.1MACDONALD RIVER 11977.6 20822.4 6.7 753 0.8 16.3 8995 2.1MACDONALD RIVER 11878 20922 6.6 753 0.8 16.3 8995 2.1MACDONALD RIVER 11778.4 21021.6 6.6 753 0.8 16.3 8994 2.1MACDONALD RIVER 11678.8 21121.2 6.6 753 0.8 16.3 8994 2.1MACDONALD RIVER 11579.2 21220.8 6.6 752 0.8 16.3 8993 2.1MACDONALD RIVER 11479.6 21320.4 6.5 752 0.8 16.3 8993 2.1MACDONALD RIVER 11380 21420 6.5 752 0.8 16.3 8992 2.1MACDONALD RIVER 11280.71 21519.29 6.5 752 0.8 16.3 8992 2.1MACDONALD RIVER 11181.43 21618.57 6.5 752 0.8 16.3 8992 2.2MACDONALD RIVER 11082.14 21717.86 6.4 752 0.8 16.3 8991 2.2MACDONALD RIVER 10982.86 21817.14 6.4 752 0.8 16.3 8990 2.2MACDONALD RIVER 10883.57 21916.43 6.4 752 0.8 16.3 8990 2.2MACDONALD RIVER 10784.29 22015.71 6.4 752 0.8 16.3 8990 2.2MACDONALD RIVER 10685 22115 6.3 752 0.8 16.3 8989 2.3MACDONALD RIVER 10585.71 22214.29 6.3 752 0.8 16.3 8989 2.3MACDONALD RIVER 10486.43 22313.57 6.3 752 0.8 16.3 8989 2.3MACDONALD RIVER 10387.14 22412.86 6.3 752 0.8 16.3 8988 2.3MACDONALD RIVER 10287.86 22512.14 6.2 752 0.8 16.3 8988 2.4MACDONALD RIVER 10188.57 22611.43 6.2 752 0.8 16.3 8988 2.4MACDONALD RIVER 10089.29 22710.71 6.2 752 0.8 16.3 8988 2.4MACDONALD RIVER 9990 22810 6.2 752 0.8 16.3 8988 2.4MACDONALD RIVER 9891.11 22908.89 6.1 752 0.8 16.3 8988 2.4MACDONALD RIVER 9792.22 23007.78 6.1 751 0.8 16.3 8988 2.4MACDONALD RIVER 9693.33 23106.67 6.1 751 0.8 16.3 8987 2.4MACDONALD RIVER 9594.45 23205.55 6.1 751 0.8 16.3 8987 2.4MACDONALD RIVER 9495.55 23304.45 6.0 751 0.9 16.3 8987 2.4MACDONALD RIVER 9396.67 23403.33 6.0 751 0.9 16.3 8987 2.4MACDONALD RIVER 9297.78 23502.22 6.0 751 0.9 16.3 8987 2.4MACDONALD RIVER 9198.89 23601.11 6.0 751 0.9 16.3 8986 2.4MACDONALD RIVER 9100 23700 5.9 751 0.9 16.3 8986 2.4MACDONALD RIVER 9001.11 23798.89 5.9 751 0.9 16.3 8986 2.4MACDONALD RIVER 8902.22 23897.78 5.8 751 0.9 16.3 8986 2.4MACDONALD RIVER 8803.33 23996.67 5.8 751 1.0 16.3 8986 2.4MACDONALD RIVER 8704.45 24095.55 5.8 751 1.0 16.3 8985 2.4MACDONALD RIVER 8605.55 24194.45 5.7 751 1.0 16.3 8985 2.3MACDONALD RIVER 8506.67 24293.33 5.7 753 1.1 16.3 9004 2.3MACDONALD RIVER 8407.78 24392.22 5.6 755 1.1 16.3 9022 2.3MACDONALD RIVER 8308.89 24491.11 5.5 755 1.1 16.3 9021 2.3MACDONALD RIVER 8210 24590 5.5 755 1.2 16.3 9021 2.3MACDONALD RIVER 8114.09 24685.91 5.4 755 1.2 16.3 9021 2.4MACDONALD RIVER 8018.18 24781.82 5.3 755 1.1 16.3 9021 2.4MACDONALD RIVER 7922.27 24877.73 5.3 755 1.1 16.3 9020 2.4MACDONALD RIVER 7826.36 24973.64 5.2 755 1.1 16.3 9020 2.4MACDONALD RIVER 7730.46 25069.54 5.2 755 1.1 16.3 9020 2.4MACDONALD RIVER 7634.54 25165.46 5.1 755 1.1 16.3 9020 2.5MACDONALD RIVER 7538.64 25261.36 5.0 755 1.0 16.3 9019 2.5MACDONALD RIVER 7442.73 25357.27 5.0 755 1.0 16.3 9019 2.5MACDONALD RIVER 7346.82 25453.18 4.9 755 1.0 16.3 9019 2.5MACDONALD RIVER 7250.91 25549.09 4.9 755 1.0 16.3 9019 2.5MACDONALD RIVER 7155 25645 4.8 755 1.0 16.3 9018 2.6MACDONALD RIVER 7059.09 25740.91 4.8 755 1.0 16.3 9018 2.6MACDONALD RIVER 6963.18 25836.82 4.7 755 1.0 16.3 9018 2.6MACDONALD RIVER 6867.27 25932.73 4.7 755 1.0 16.3 9018 2.6MACDONALD RIVER 6771.36 26028.64 4.6 755 1.0 16.3 9017 2.6MACDONALD RIVER 6675.46 26124.54 4.6 754 1.0 16.3 9017 2.7MACDONALD RIVER 6579.54 26220.46 4.5 754 1.0 16.3 9017 2.7MACDONALD RIVER 6483.64 26316.36 4.5 754 0.9 16.3 9017 2.7MACDONALD RIVER 6387.73 26412.27 4.5 754 0.9 16.3 9017 2.7MACDONALD RIVER 6291.82 26508.18 4.4 754 0.9 16.3 9016 2.8MACDONALD RIVER 6195.91 26604.09 4.4 754 0.9 16.3 9016 2.8MACDONALD RIVER 6100 26700 4.4 754 0.9 16.3 9016 2.8MACDONALD RIVER 6004.37 26795.63 4.3 754 0.9 16.3 9016 2.8MACDONALD RIVER 5908.75 26891.25 4.3 754 0.9 16.3 9016 2.8MACDONALD RIVER 5813.12 26986.88 4.3 754 0.9 16.3 9016 2.7MACDONALD RIVER 5717.5 27082.5 4.2 754 0.9 16.3 9016 2.7MACDONALD RIVER 5621.87 27178.13 4.2 754 0.9 16.3 9016 2.7MACDONALD RIVER 5526.25 27273.75 4.2 754 0.8 16.3 9016 2.7MACDONALD RIVER 5430.62 27369.38 4.2 754 0.8 16.3 9016 2.7MACDONALD RIVER 5335 27465 4.1 754 0.8 16.3 9016 2.7MACDONALD RIVER 5239.37 27560.63 4.1 754 0.8 16.3 9016 2.6MACDONALD RIVER 5143.75 27656.25 4.1 754 0.8 16.3 9016 2.6MACDONALD RIVER 5048.12 27751.88 4.1 754 0.8 16.3 9016 2.6MACDONALD RIVER 4952.5 27847.5 4.0 754 0.8 16.3 9016 2.6MACDONALD RIVER 4856.87 27943.13 4.0 754 0.8 16.3 9016 2.6MACDONALD RIVER 4761.25 28038.75 4.0 754 0.8 16.3 9016 2.6MACDONALD RIVER 4665.62 28134.38 4.0 753 0.8 16.3 9015 2.6MACDONALD RIVER 4570 28230 3.9 753 0.8 16.3 9015 2.5MACDONALD RIVER 4470.55 28329.45 3.9 753 0.8 16.3 9016 2.6MACDONALD RIVER 4371.11 28428.89 3.9 753 0.8 16.3 9016 2.6MACDONALD RIVER 4271.67 28528.33 3.9 753 0.8 16.3 9015 2.6MACDONALD RIVER 4172.22 28627.78 3.8 753 0.8 16.3 9015 2.6MACDONALD RIVER 4072.78 28727.22 3.8 753 0.8 16.3 9015 2.7MACDONALD RIVER 3973.33 28826.67 3.8 753 0.9 16.3 9015 2.7MACDONALD RIVER 3873.89 28926.11 3.7 753 0.9 16.3 9015 2.7MACDONALD RIVER 3774.45 29025.55 3.7 753 0.9 16.3 9015 2.8MACDONALD RIVER 3675 29125 3.7 753 0.9 16.3 9015 2.8MACDONALD RIVER 3579.32 29220.68 3.6 753 0.9 16.3 9015 2.8MACDONALD RIVER 3483.64 29316.36 3.6 753 0.9 16.3 9014 2.8MACDONALD RIVER 3387.96 29412.04 3.6 753 0.9 16.3 9014 2.8MACDONALD RIVER 3292.27 29507.73 3.5 753 0.9 16.3 9015 2.7MACDONALD RIVER 3196.59 29603.41 3.5 753 0.9 16.3 9014 2.7MACDONALD RIVER 3100.91 29699.09 3.4 753 0.9 16.3 9014 2.7MACDONALD RIVER 3005.23 29794.77 3.4 753 0.9 16.3 9014 2.7
APPENDIX D: DESIGN FLOOD RESULTS Lower Macdonald River Flood Study
MACDONALD RIVER 2909.54 29890.46 3.4 753 0.9 16.3 9014 2.7MACDONALD RIVER 2813.86 29986.14 3.3 753 0.9 16.3 9014 2.6MACDONALD RIVER 2718.18 30081.82 3.3 753 0.9 16.3 9014 2.6MACDONALD RIVER 2622.5 30177.5 3.3 753 0.9 16.3 9014 2.6MACDONALD RIVER 2526.82 30273.18 3.2 753 0.9 16.3 9013 2.6MACDONALD RIVER 2431.14 30368.86 3.2 753 0.9 16.3 9013 2.6MACDONALD RIVER 2335.46 30464.54 3.2 753 0.9 16.3 9013 2.6MACDONALD RIVER 2239.77 30560.23 3.2 753 0.9 16.3 9013 2.6MACDONALD RIVER 2144.09 30655.91 3.2 753 0.9 16.3 9013 2.6MACDONALD RIVER 2048.41 30751.59 3.2 753 0.8 16.3 9013 2.5MACDONALD RIVER 1952.73 30847.27 3.2 753 0.8 16.3 9013 2.5MACDONALD RIVER 1857.04 30942.96 3.2 753 0.8 16.3 9013 2.5MACDONALD RIVER 1761.36 31038.64 3.2 753 0.8 16.3 9012 2.5MACDONALD RIVER 1665.68 31134.32 3.2 753 0.8 16.3 9013 2.5MACDONALD RIVER 1570 31230 3.2 753 0.8 16.3 9013 2.5MACDONALD RIVER 1471.87 31328.13 3.2 753 0.9 16.3 9013 2.6MACDONALD RIVER 1373.75 31426.25 3.2 753 0.9 16.3 9013 2.6MACDONALD RIVER 1275.62 31524.38 3.2 753 0.9 16.3 9013 2.6MACDONALD RIVER 1177.5 31622.5 3.2 753 0.9 16.3 9013 2.7MACDONALD RIVER 1079.37 31720.63 3.2 753 0.9 16.3 9013 2.7MACDONALD RIVER 981.25 31818.75 3.2 753 1.0 16.3 9013 2.8MACDONALD RIVER 883.12 31916.88 3.2 753 1.0 16.3 9013 2.9MACDONALD RIVER 785 32015 3.2 753 1.0 16.3 9014 3.0MACDONALD RIVER 686.87 32113.13 3.2 753 1.1 16.3 9014 3.1MACDONALD RIVER 588.75 32211.25 3.2 753 1.1 16.3 9014 3.2MACDONALD RIVER 490.62 32309.38 3.2 753 1.2 16.3 9014 3.3MACDONALD RIVER 392.5 32407.5 3.2 753 1.2 16.3 9014 3.5MACDONALD RIVER 294.37 32505.63 3.2 753 1.3 16.3 9014 3.8MACDONALD RIVER 196.25 32603.75 3.2 753 1.4 16.3 9014 4.1MACDONALD RIVER 98.12 32701.88 3.2 753 1.5 16.3 9014 4.8MACDONALD RIVER 0 32800 3.2 753 1.7 16.3 9015 5.8
WRIGHTS CREEK 1410.78 0 7.0 135 0.6 16.3 566 0.3WRIGHTS CREEK 1313.86 96.92 7.0 132 0.6 16.3 554 0.3WRIGHTS CREEK 1216.93 193.85 7.0 128 0.5 16.3 543 0.3WRIGHTS CREEK 1120.01 290.77 7.0 124 0.5 16.3 531 0.3WRIGHTS CREEK 1023.09 387.69 7.0 119 0.5 16.3 520 0.3WRIGHTS CREEK 926.16 484.62 7.0 115 0.4 16.3 508 0.3WRIGHTS CREEK 829.24 581.54 7.0 111 0.4 16.3 498 0.3WRIGHTS CREEK 732.32 678.46 7.0 107 0.4 16.3 487 0.3WRIGHTS CREEK 635.4 775.38 7.0 103 0.3 16.3 477 0.3WRIGHTS CREEK 538.47 872.31 7.0 98 0.3 16.3 466 0.3WRIGHTS CREEK 441.55 969.23 7.0 94 0.3 16.3 456 0.3WRIGHTS CREEK 344.63 1066.15 7.0 91 0.3 16.3 447 0.3WRIGHTS CREEK 247.7 1163.08 7.0 87 0.3 16.3 437 0.3WRIGHTS CREEK 150.78 1260 7.0 83 0.3 16.3 428 0.3WRIGHTS CREEK 75.39 1335.39 7.0 80 0.2 16.3 421 0.3WRIGHTS CREEK 0 1410.78 7.0 77 0.2 16.3 414 0.3