corangamite catchment management authority

August 2003

Corangamite Catchment Management Authority

Review of Regional Drainage Schemes Model Calibration Report

Report

31/12846/3360 Review of Regional Drainage Schemes Model Calibration Report

Contents

1. Introduction 1

1.1 Objectives 1 1.2 Background 1 1.3 Purpose of Model 2 1.4 Methodology 2

2. Description of Model 3

2.1 Model Type and Functionality 3 2.2 Data Availability and Model Inputs 3 2.3 Adequacy of Raw Data 6 2.4 Hydrological Context - Lake Corangamite 7 2.5 Modelling Period 12 2.6 Drainage Scheme System Network Diagram 15 2.7 IQQM System and Input Files 15

3. Model Inputs 17

3.1 Storage Information 17 3.2 Rainfall and Evaporation Data 17 3.3 Flow and Salinity Data 19 3.4 Irrigation Data 27 3.5 Operation Rules 28

4. Model Calibration and Validation 30

4.1 Introduction 30 4.2 Model Calibration 1986 – 2002 30 4.3 Annual Volumes and Salt Loads 40 4.4 Model Verification 1974 – 2002 46

5. Conclusion 49

6. Abbreviations and Units of Measure 50

6.1 Abbreviations 50 6.2 Units and Conversions 50

7. References 51


Table Index Table 2-1: Historical Corangamite Level Probability Pre and Post

Scheme 11 Table 3-1: Storages Included in the Model 17 Table 3-2: Class A Pan Coefficients 18 Table 3-3: Regression Factors for Flow and Salinity Data 20 Table 3-4: Rainfall Adjustment and Calibration Factors 22 Table 3-5: Storage Inflow Salinity (EC) Coefficients 23 Table 3-6: Groundwater Parameters 25 Table 3-7: Groundwater Inflows 26 Table 3-8: Irrigation Licence Volumes along the Barwon River 27 Table 3-9: Monthly Irrigation Extraction Factors 28 Table 4-1: Annual Flow and Salt Load Comparison 45 Table D-1 Groundwater Parameters 57

Figure Index Figure 2-1 – Input Data 5 Figure 2-2 – Calibration Data 5 Figure 2-3 - Corangamite Levels and Regional Rainfalls 8 Figure 2-4: Regional Annual Rainfall Probability 8 Figure 2-5: Corangamite Regional Rainfall Long Term Patterns 9 Figure 2-6: Corangamite Level Probability- Prior to Drainage

Scheme 10 Figure 2-7: Corangamite Level Probability- Post Drainage Scheme 10 Figure 2-8 Lake Colac and Lake Corangamite Historic Levels 14 Figure 2-9 System Schematic 16 Figure 4-1– Lake Colac Calibration (1986 – 2002) 32 Figure 4-2 – Lake Corangamite Calibration (1986 – 2002) 33 Figure 4-3 – Cundare Pool Calibration (1986 – 2002) 34 Figure 4-4 – Lough Calvert Drainage Channel Calibration (1986 –

2002) 36 Figure 4-5 – Woady Yaloak Drainage Channel Calibration (1986 –

2002) 37 Figure 4-6 – Lough Calvert Drainage Channel Trigger 38 Figure 4-7 – Woady Yaloak Drainage Channel Trigger 39 Figure 4-8 – Barwon River @ Inverleigh Calibration 41 Figure 4-9 – Barwon River @ Inverleigh Calibration 42 Figure 4-10 – Barwon River @ Pollocksford Calibration 43


Figure 4-11 – Barwon River @ Pollocksford Calibration 44 Figure 4-12 – Lake Colac and Lake Corangamite Verification 47 Figure 4-13 – Barwon River Verification 48

Appendices A Locality Plan B IQQM Files C Storage Information D Groundwater Summary

1 31/12846/3360 Review of Regional Drainage Schemes Model Calibration Report

1. Introduction

1.1 Objectives This report details the setup and calibration of the water resource model for:

The Lake Colac and the Lough Calvert Drainage Scheme; and

The Lake Corangamite and the Woady Yaloak Diversion Scheme.

Appendix A contains a map showing the two drainage schemes.

The overall objective of this part of the project was to develop a water balance model that would simulate historical storage level, stream flow and water quality (salinity) records in the two drainage schemes.

This report includes details on the water resource model setup, data collection, model inputs, model calibration and verification.

1.2 Background This report was produced for the “Review of the Lake Colac and Lake Corangamite Drainage Schemes” being undertaken by GHD Pty Ltd on behalf of the Corangamite Catchment Management Authority.

It is assumed that the reader is familiar with the two drainage schemes being modelled. Additional background information can be obtained from the Background Report (GHD, 2003a), Community Consultation Report (GHD, 2003b) and the Model Scoping Report (GHD, 2003c), which have been produced as part of the overall project.

Generally, the work detailed in this report follows the overall methodology detailed in the Model Scoping Report (GHD, 2003c). The main features of the proposed work detailed in this report included:

A detailed analysis over a short period that includes anecdotal information from stakeholders to show the future performance of the schemes against historic performance in terms of lake levels, diversion flows and Barwon River salinities. Actual data is used without introducing concerns over data extension techniques.

A longer term analysis to provide the information on water level frequency of vital interest to the landowners adjacent to the Lakes. Further discussion on the modelling period is provided in Section 2.2.

Utilisation of the results from the above analyses to supplement the considerable data from previous studies.

A study of groundwater interactions, which will progress the understanding of these processes using recent data.


1.3 Purpose of Model The purpose of the model is to quantify the effects of various structural and non-structural changes to the drainage schemes. The various impacts that need to be assessed include:

The long term changes to “normal” levels in specified storages;

Changes to the frequency of flooding of specified areas;

Changes to flow regimes in specified streams; and

Changes to salinity concentrations and salt loads in various storages and streams.

1.4 Methodology The development of the model involved a number of major activities. These activities are summarised below and are discussed in detail in the following sections of the report. The major activities included:

Model selection;

Data collection and verification;

Selection of calibration and modelling periods;

Derivation of model inputs;

Clarification of historical system performance and operation; and

Model calibration and verification.


2. Description of Model

2.1 Model Type and Functionality The Integrated Quantity-Quality Model (IQQM) was selected for the modelling of this drainage scheme. IQQM is a computer modelling tool developed by the New South Wales Department of Land and Water Conservation for use in planning and evaluation of water resource management policies. The model is a generalised hydrological simulation package, which is capable of application to regulated and unregulated streams, and is designed to be capable of addressing water quality and water quantity issues. The model operates on a continuous basis for periods up to hundred of years, and is designed to operate at a daily time step (DLWC, 2000).

The key features that were required for the drainage schemes review included reservoir operation, irrigation demands, groundwater interactions, environmental flow requirements (particularly relevant for the drainage scheme operation triggers), in stream water quality modelling and flow routing. IQQM has provision for these features. To date, only the salinity component of the in stream water quality model has been activated.

IQQM is designed to operate on a daily time step and to route flows, which are two significant advantages over other system models.

2.2 Data Availability and Model Inputs Two forms of recorded data were required for this model, these being; Input Data which was used to derive model inputs, and Calibration Data which was used to compare actual and simulated outputs at specified locations.

2.2.1 Input Data

Input Data comprised:

Storage Information;

Rainfall and Evaporation Records;

Inflow data to storages and headwater streams;

Salinity records for storages and streams;

Irrigation usage Information; and

Groundwater data.

Generally, there was limited daily data available for the establishment of model inputs, particularly salinity data. Figure 2-1 shows the extent of data that was available for the period 01/01/ 1974 to 31/12/2002. Gaps in the datasets were filled using various techniques that are explained in Section 2.3. Available data prior to 1974 is described in GHD (2003c).


2.2.2 Calibration Data

Specific data required for the purpose of calibrating the model included:

Storage levels (volumes), releases and salinity;

Releases along the two drainage channels; and

Flow and salinity records at various locations along the Baron River.

Calibration data was obtained from several sources including daily gauged records, weekly record sheets, and original operator records. Figure 2-2 shows the extent of calibration data that was available for the period 01/01/ 1974 to 31/12/2002. This figure highlights the lack of salinity data prior to 1986.


Figure 2-1 – Input Data

Figure 2-2 – Calibration Data

AVAILABILITY OF MODEL INPUT DAILY DATA

Birregurra Ck @ Irrewarra

Barwon River @ Conn's Lane

Jan-

1974

Jan-

1976

Jan-

1978

Jan-

1980

Jan-

1982

Jan-

1984

Jan-

1986

Jan-

1988

Jan-

1990

Jan-

1992

Jan-

1994

Jan-

1996

Jan-

1998

Jan-

2000

Jan-

2002

FLOW DATA

SALINITY DATA

Pirron Yallock Creek

W oady Yaloak Channel

W oady Yaloak River @ Cressy

Dean's Ck @ Lake Colac

Birregurra Ck @ Irrewarra

Dean's Ck @ Lake Colac

W oady River @ Cressy

Lough Calvert Drainage Channel

W arram bine Ck @ W arram bine

Leigh River @ Shelford

NO RECORDS - Lough Calvert Drainage Channel

NO RECORDS - Pirron Yallock Creek

W oady Yaloak River @ Cressy

W arram bine Ck @ W arrambine

Leigh River @ Shelford

AVAILABILITY OF CALIBRATION DATA

Jan-

74

Jan-

76

Jan-

78

Jan-

80

Jan-

82

Jan-

84

Jan-

86

Jan-

88

Jan-

90

Jan-

92

Jan-

94

Jan-

96

Jan-

98

Jan-

00

Jan-

02FLOW AND LEVEL DATA

SALINITY DATA

Lake Colac Height

Lake Colac Releases

Barwon @ Inverleigh

Barwon @ Pollocksford

Lake Corangam ite Levels

Cundare Pool Levels

W oady Yaloak Diversion Channel

Lake Colac Salinity

Barwon @ Inverleigh Salinity

Barwon @ Pollocksford Salinity

Lake Corangamite Salinity

Cundare Pool Salinity

W oady Yaloak Diversion Channel Salinity

Lough Calvert Channel @ W arrowie Cut

Birregurra @ Irrewarra

Birregurra @ Conn's Lane

Barwon @ W inchelsea

Lake Colac Releases Salinity

Birregurra @ Irrewarra Salinity

Birregurra @ Conn's Lane Salinity

Barwon @ W inchelsea Salinity

LEGEND Daily Data W eekly Data


2.3 Adequacy of Raw Data This section describes the nature and the period of raw surface water data available for analysis. Anomalies in the data found during modelling are described in a later section. Groundwater data is described in Section 3.

2.3.1 Daily Surface Water Data

As described in Section 2.2 the nature of the available data varies throughout time. Much of the necessary flow data was available from early 1974 in daily format. Subsequent to early 1993, much of the necessary flow and salinity data were both in daily format.

Short missing periods of flow were filled by interpolation. Otherwise, larger flow gaps were filled by correlation with adjacent relevant stations. Missing periods of salinity were “filled” using regressions between flow and salinity. Where the necessary model input data were not in daily format, for example prior to 1993, these regressions may affect the performance of the model. Section 3.3 describes the regressions used.

A check on event flow volumes between upstream and downstream gauges was possible for the Barwon River. It was found that there was an unexpected reduction in volume for some events below Conn’s Lane, suggesting a possible error in the high flow rating for large events at Conn’s Lane. As this does not greatly affect model performance, the cause was not pursued.

Tributary flows and salt loads were derived from the difference between gauge values using an appropriate lag of a multiple of days. It was found that this created unexpected flow volume and salt load losses and is due to a combination of data errors, small differences in the values, the variation of the lag with flow (rather than a constant used here) and complex phenomena evident in flow and salinity routing and tributary salt loads. Irrigation and water supply abstractions are involved in the calculation and approximate values varying with season had to be used. The overall problem of tributary flow and salinity estimation was overcome, in the main, by taking large tributary catchments and setting any negative values to zero. Interaction between the waterways and the aquifers are included in the gauging record.

2.3.2 Weekly Surface Water Data

Weekly data was available for some parts of the drainage system, as indicated in the previous section, having been collected by current and previous operators. None of this data was suitable for model inputs and its main purpose was to assist with model calibration and verification.

2.3.3 Data Deficiencies

Minor deficiencies can be easily overcome with standard fixes, such as those described above. One significant deficiency in this project was found to be the inadequacy of records of inflow to the lakes. In the case of Lake Colac only some 14% of the catchments are gauged. For Corangamite, approximately 15% of the


catchments are gauged. Although inflow volumes may be back calculated from level and outflow information this was not appropriate where groundwater exchange is modelled and is a calibration variable. In the case of Corangamite, inflows from Cundare Pool are an operational variable but few records exist. Furthermore, in the case of Lake Colac, accurate outflow records are not available prior to 1986.

A partial solution was adopted by applying global calibration factors to the inflows, using different factors for each lake and using different factors before and after 1993. These factors are reported in a later section. It appears that a similar approach was adopted in earlier studies (Adams, 1990).

2.3.4 Adequacy of Records Period

Ideally, the period of modelling should be as long as the data permits so that the operational rules may be tested against the widest range (largest sample) of hydrologic conditions. However, data extension techniques introduce errors and a balance must be struck between the modelling errors in the data extension, and the inherent data deficiencies against the increased reliability brought about by a larger sample size.

Another consideration in the Corangamite Region is the distinctly different climatic conditions before and after 1950 (approximately) as reported by the Rural Water Commission (1988) and illustrated in Section 2.4.

In this project daily rainfall exists for the longest period, commencing near the beginning of the 20th Century giving some 100 years of “hydrologic data”. This data might be used in rainfall runoff modelling to generate inflow volumes for the main lakes, one of the main modelling variables. The other inputs are the river salinities for the Barwon at Winchelsea and downstream of the Leigh River which serve as triggers for releases from the drainage schemes. Potential errors are large with rainfall runoff modelling particularly for the dry catchments north and east of the schemes and any error in runoff quantity is compounded in the salinity quantity.

As described above, a significant body of the necessary flow and salinity data did not become available until 1974. It is noteworthy that this is the period of record analysed in previous investigations of the scheme.

2.4 Hydrological Context - Lake Corangamite

2.4.1 Information

Records of rainfall and Lake Corangamite storage levels for the past 100 years have been collected. Lake Corangamite annual maximum levels since 1961 were derived from monthly or weekly readings. Little is known about the origin of earlier readings and is assumed to be annual maxima. Average annual rainfalls for the Colac, Camperdown and Linton recording stations were defined as the regional mean rainfall and as a representation of the hydrologic conditions affecting Lake Corangamite. A 3 year moving average regional rainfall was also calculated. These data are shown on Figure 2-3 together with Corangamite Annual Maximum levels. Rainfall probabilities are shown on Figure 2-4.


Lake Corangamite Levels and Regional Rainfalls

400

600

800

1000

1200

1400

1600

1800

1870

1875

1880

1885

1890

1895

1900

1905

1910

1915

1920

1925

1930

1935

1940

1945

1950

1955

1960

1965

1970

1975

1980

1985

1990

1995

2000

2005

2010

Rain

fall

(mm

/yea

r)

110

111

112

113

114

115

116

117

118

Annu

al M

axim

um W

ater

Lev

el (m

AHD

)

Rainfall Regional MeanAnn. Max. Level3 per. Mov. Avg. (Rainfall Regional Mean)

Prior to Drainage Scheme After to Drainage Scheme

Figure 2-3 - Corangamite Levels and Regional Rainfalls

Regional rainfall

400

500

600

700

800

900

1000

1100

1200

AEP (1 in Y)

Rain

fall

(mm

/yea

r)

Flood Series

LP3 Distribution

Confidence Limits

0.99 AEP0.90.950.98 0.30.50.70.8 0.10.2 0.010.020.05

100502010521.111 1.25

Figure 2-4: Regional Annual Rainfall Probability


Annual rainfall deviations from the long term average rainfall were calculated to examine long term climatic trends. As shown on Figure 2-5, it was found that the earlier period of the rainfall record was significantly drier than the latter periods. Earlier researchers have identified this weather phenomenon and have attributed it to statistically normal variations in weather. Such phenomena highlight the problem of determining long term statistics from short term samples, particularly in the Corangamite area.

Corangamite Region Annual Departure from Mean

-400.0

-300.0

-200.0

-100.0

0.0

100.0

200.0

300.0

400.0

500.0

1877

1881

1885

1889

1893

1897

1901

1905

1909

1913

1917

1921

1925

1929

1933

1937

1941

1945

1949

1953

1957

1961

1965

1969

1973

1977

1981

1985

1989

1993

1997

2001

Rain

fall

(mm

)

Series2

Prior to Drainage Scheme After Drainage Scheme

Figure 2-5: Corangamite Regional Rainfall Long Term Patterns

Corangamite water level data were fitted to log-pearson probability distributions, separately for the periods pre and post the drainage scheme. Data for six years after the scheme commenced was excluded to eliminate significant carryover effects. These are shown in Figure 2-6 and Figure 2-7and summarised in Table 2-1.


Annual Max (69 years) Prior to Scheme

116.00

116.50

117.00

117.50

118.00

118.50

AEP (1 in Y)

Peak

Lev

el m

AH

D

Flood Series

LP3 Distribution

Confidence Limits

0.99 AEP0.90.950.98 0.30.50.70.8 0.10.2 0.010.020.05

100502010521.111 1.25

Figure 2-6: Corangamite Level Probability- Prior to Drainage Scheme

Annual Max (37 years) After Scheme

114.00

114.50

115.00

115.50

116.00

116.50

117.00

117.50

118.00

118.50

AEP (1 in Y)

Peak

Lev

el m

AHD

Flood Series

LP3 Distribution

Confidence Limits

0.99 AEP0.90.950.98 0.30.50.70.8 0.10.2 0.010.020.05

100502010521.111 1.25

Figure 2-7: Corangamite Level Probability- Post Drainage Scheme


Table 2-1: Historical Corangamite Level Probability Pre and Post Scheme

RWC 19913 Annual Exceedance Probability (%)

Pre scheme

(69 years)

Post scheme

(37 years)1

Post scheme

(29 years)2 Without

/pre

With

/post

1 118.0 117.1 117.0 119.2 118.3

2 117.7 117.0 116.9

5 117.4 116.8 116.7

10 117.1 116.6 116.5 118.3 116.1

20 116.9 116.4 116.3 117.4 115.3

50 116.6 115.9 115.7 115.8 114.2

Note 1 - Period of scheme operation less carryover period Note 2 - Period of substantial records, 1974 to 2002 Note 3 - Source RWC 1991, Appendix 1

2.4.2 Interpretation

Inspection of the rainfalls and levels prior to implementation of the drainage scheme (Figure 2-3) reveals that the annual maximum level bears a slight relationship with the annual regional rainfall (r2 = 0.6). An annual rainfall in excess of 1100 mm/year is associated with the highest recorded level of 118.03 m AHD. Such a rainfall has a probability less than a 1% annual exceedance probability (AEP) as shown on Figure 2-4. This probability is consistent with the direct frequency analysis of levels.

A simple relationship between rainfall and lake level is not evident after implementation of the scheme and this is attributed to the impact of diversion of a large proportion of the lake inflows on what is effectively a random basis.

The probability distributions of storage levels derived by RWC (1991) are significantly different from those derived by direct frequency analyses of the data. Of particular interest, are the significant differences in the slope (standard deviation) of the distributions. That is, the synthetic distributions from RWC (1991) are significantly steeper than evident in the level data. The basis of the RWC analyses is not documented in detail but is said to be based on 12 years of daily data, 33 years of monthly data and 66 years of annual data. Other than the daily data, this data was not available in this study and it was not possible to compare flow variabilities. Comparison of rainfall variabilities does not explain the differences. The RWC results cannot be accepted in the absence of details of the data generation model and methods for deriving statistical parameters used in the generation of Corangamite inflows, rainfalls and evaporation.


2.5 Modelling Period

2.5.1 Discussion

The approved modelling scoping report (GHD, 2003b) proposed analysis using 10 years of detailed flow and salinity data and then some 70 years of flow data with estimated salinities.

The reasons for proposing a 70 year analysis were:

To give a greater sample size than possible with recorded flows from which statistical interpretations can be made with greater certainty, particularly with respect to flood frequency of the lake. A sample of 70 years compared with 30 years would narrow the confidence limits by 40% (at the 1 in 5 to 1 in 20 year ARI event); and

To take full advantage of the Barwon River 70 year flow time series available from Barwon Water’s headworks modelling which reflects various headworks operating scenarios and demand levels. These time series can also be incorporated within a shorter analysis, if required.

In order to create a 70 year analysis, streamflow records and salinities at a number of locations would need to be created by data extension techniques at locations as follows:

Woady Yaloak @ Cressy Extend 1930 to 1958

GS 234203 (and other catchments) for Corangamite inflows Extend 1930 to 1964

GS 234209 (and other catchments) for Colac Inflows Extend 1930 to 1975

Barwon tributary flows Upstream of Winchelsea Extend 1930 to 1970

Barwon Tributary flows, Winchelsea to Pollocksford (including Leigh River and Warrambine Creek)

Extend 1930 to 1970

Rainfall/runoff correlations have proven to be unsatisfactory. The most appropriate method of data extension would be rainfall runoff modelling. Although modelling errors arise, especially at the daily level of resolution, the overall error is considered not as great as would arise from sampling error. However, there is little data available for model verification in the earlier periods and the reliability of the overall results cannot be verified for that period.

The hydrologic variability since 1952 is indicated by the storage level plots for Lake Corangamite and Lake Colac in Figure 2-8. The records post 1955 are affected by the scheme operation and modelling suggests that the carryover effect can last for 4 to 6 years. It is shown that for Lake Colac, the highest water levels were recorded in the past 30 years. Lake Corangamite levels were much higher throughout the sixties than in the seventies which is likely to be related to the commencement of the Corangamite drainage scheme in 1959.


The results of the model calibration and verification work to date indicate deficiencies in the collected data in a number of areas such as:

Records of representative inflows to Lake Colac and Corangamite;

Accuracy of flow and salinity data from which tributary Barwon flows and salt loads can be determined; and

Insufficient records of transfers from Cundare Pool to Lake Corangamite (or records of outflows from Cundare Pool).

Whilst these deficiencies do not prevent comparison of operating options, they do detract from the value in extending the modelling period into periods where less recorded data is available for verification.

The model calibration/verification period commencing in 1974 encompasses two relatively wet periods, one finishing in 1975 and another finishing in 1992, and two dry periods, one finishing in 1982/1990 and another in 2000. It excludes several historically very wet years and the historically dry period prior to 1946. Selective extension of the modelling period could have a significant impact on estimates of level frequencies for the lakes depending on how many extra wet or dry years are added. Extension to include the planned 1927 to 2002 may bias the results towards the dry period in the earlier part of the record.

Use of the more recent 30 year period encompasses a period that is wetter on average and is therefore conservative in terms of lake levels and damages (high) and impacts on the Barwon salinities (more diversions).

The 29 year modelling period is considered to be more than sufficient to test the impact of scheme changes on environmental factors.


Figure 2-8 Lake Colac and Lake Corangamite Historic Levels

Note 1 – Lake Colac chart sourced from SR&WSC (1979) Note 2 – Lake Corangamite chart sourced from Adams (1990)

LAKE CORANGAMITE


2.5.2 Recommended Modelling Period

Having regard for the above factors, the recommended modelling period is the 29 year period from 1974 to the end of 2002. As described above, this period includes climatic conditions which are both significantly wet (1970s) and significantly dry (early 1980s). This is considered to be adequate for the purpose of appraising the impacts of operating rule changes on lake level frequency and on Barwon River Salinities.

2.6 Drainage Scheme System Network Diagram Figure 2-9 shows the network diagram detailing the storages, rivers, creeks described in the model system file.

2.7 IQQM System and Input Files The IQQM model requires data files in specific formats, which are generated within IQQM. A complete listing of all model input files and calibration files is provided in Appendix B.


3. Model Inputs

3.1 Storage Information A summary of the storages included in the model is provided in Table 3-1. Detailed information including stage/volume/area relationships, stage discharge relationships and simulation start conditions is included in Appendix C.

Table 3-1: Storages Included in the Model

Storage Capacity (ML) Outlet EL (mAHD)

Spillway EL (mAHD)

Lake Colac 90,000 115.25 117.40

Spiers Depression 2,500 112.35 113.10

Lower Lough 40,000 111.30 114.00

Middle Lough 55,000 115.40 115.40

Upper Lough 48,800 116.00 116.00

The Sanctuary 19,800 116.00 116.00

Lake Corangamite 1,860,000 119.85 119.85

Lake Gnarpurt 150,000 116.00 118.21

Cundare Pool1 60,145 116.57 117.94

Lake Martin1 20,000 NA NA

Black Bridge Pool 650 NA NA

Lake Murdeduke 5,000 NA NA

Note 1 Included as one storage in the model

Stage/volume/area relationships were obtained from SR& WSC (1979) and Adams (1990). Some extension of this information was undertaken using available contour plans. However, generally there has been no work undertaken to verify the previously published information.

3.2 Rainfall and Evaporation Data

3.2.1 Rainfall

Rainfall data is a required input for the modelling of storages. The gauging station at Colac (GS 90147) was used as the input for all storages on the Lough Calvert Drainage Scheme, and the gauging station at Leslie Manor (GS 90053) was used as the input for all storages on the Woady Yaloak Drainage Scheme.


Daily rainfall has been recorded at Colac (GS 90147) since 1884. Gaps in the data were in-filled using a regression with Leslie Manor rainfall data (GS 234602).

Daily rainfall at Leslie Manor (GS 234602) was recorded between 1898 and 2000. There were no gaps in the record for the period 1974 to 2000 (except those that related to aggregation). A regression with Colac rainfall data (GS 90147) was used for data between 2000 and 2002.

3.2.2 Evaporation

Evaporation is also a required input for the modelling of storages. Daily pan evaporation data from Wurdee Boluc Reservoir (GS 87126) was used for all storages in the model. The available data from Wurdee Boluc was complete for the period 1974 to 2002.

Pan evaporation was converted to lake evaporation using the following equation:

EL = EP x FP

Where: EL = Lake evaporation in mm

EP = Pan evaporation in mm

FP = Monthly Pan Coefficient, refer to Table 3-2.

Table 3-2: Class A Pan Coefficients

Month Pan Coefficient (FP)

January 0.86

February 0.87

March 0.87

April 0.82

May 0.78

June 0.69

July 0.66

August 0.68

September 0.82

October 0.97

November 0.85

December 0.83

Source: Adams, 1990


3.3 Flow and Salinity Data Three different groups of flow and salinity were required in the model. Three groups included:

Streamflows Headwater inputs for major streams and creeks. Generally obtained from historical gauged flow records.

Storage Inflows Local inflows to each storage. Derived from area/flow correlations using historical gauged flow records.

Groundwater Inflows Groundwater inputs/outputs were developed from regional hydrogeological assessment.

Further information on the generation of each of these inflows is provided in the following sections.

3.3.1 Streamflows

Barwon River, Birregurra Creek, Warrambine Creek and Leigh River Data

Times series data of flow and salinity were required for the Barwon River at locations and for purposes as follows:

Location Purpose

Birregurra Creek tributary inflows upstream of Conn’s Lane

Tributary input to model

Barwon River and tributaries upstream of Winchelsea (including inflows upstream of Conn’s Lane)

Tributary input above the model operational trigger point at Winchelsea

Barwon River and tributaries between Winchelsea and Inverleigh

To give model output for comparison with historical conditions at Inverleigh

Barwon River and tributaries between Inverleigh and Pollocksford including Leigh River and Warrambine Creek

To give model trigger point and allow comparison of model output versus historical conditions.

Available records at each of these and nearby stations are described in Section 2. Missing flow data were filled using the regression coefficients listed in Table 3-3. Each regression was derived from all available suitable data at the correlated station. Missing salinity data were derived by a daily regression between mean flow and salinity.

The regression equation used for flow was as follows:

Q[2] = A x Q[1]B

Where: Q[2] = Flow at correlated gauge

Q[1] = Flow at reference gauge


The regression equation used for salinity was as follows:

EC = A x QB Where: EC = mean daily salinity in microsiemens/cm

Q = mean daily flow in ML/d

A & B are regression coefficients

Table 3-3: Regression Factors for Flow and Salinity Data

Location Type Correlated Site

A B

Flow NR Birregurra Ck @Irrewarra

GS 233249 EC GS 233249 14577 -0.4190

Flow NR Birregurra Ck @ Conn’s Lane GS 233211

EC GS 233211

Flow NR Barwon R at Conn’s Lane

GS 233224 EC GS 233224 937 -0.1365

Flow GS 233218 0.999 1 Barwon R at Winchelsea

GS 233201 EC GS 233201 1505 -0.1354

Flow GS 233201 1.001 1 Barwon R at Inverleigh

GS 23328 EC GS 233218 3512 -0.2629

Flow NR Barwon R @ Pollocksford

GS 233200 EC GS233200 2617 -0.1655

Flow GS 234200 Woady Yaloak R @ Cressy

GS 234201 EC GS 234200 2617 -0.1655

Note: NR = not required

Tributary flows and salt loads were derived by subtraction of daily flows, allowing for apparent travel times, in multiples of days as necessary.

This method is approximate as the routing of flow and salt varies with the magnitude of the flow and such phenomena cannot be accounted for by a constant lag and subtraction. Accordingly, occasional negative tributary flows and salt loads were generated. These were set to zero before inclusion in the simulation model. The errors so generated did not greatly affect the mean flows and were considered acceptable.


The tributary flow was calculated as:

QTt = Qdst – Qust-x + IRR t The tributary salinity was calculated as:

TDSt = (Qdst x TDSdst – Qust-x x TDSust-x+IRRt x TDSdst)/QTt Where: Q = flow in ML/d,

IRR = irrigation demand in ML/d

x = lag in days

ds = reference to downstream

us = reference to upstream

T = reference to tributary

t = tth day

TDS = salinity concentration in mg/L (or kg/ML)

During certain periods, the salt loads between the two gauges on Birregurra Creek were observed to decrease. This could not be explained other than small errors in the salinity and flow records at one or both gauges. These errors do not detract from the overall results but they do inhibit close scrutiny of groundwater interactions along the creek.

Woady Yaloak River

Inflows from the Woady Yaloak River were obtained from GS 234201 (Cressy). The data set for the period 1/01/1974 to 31/12/02 was substantially complete, and very little gap filling was required. Where necessary an area/flow correlation using GS 234200 (Pitfield) was used.

Salinities from the Woady Yaloak River were taken from the gauged data and was gap filled using a regression developed from that gauge. The parameters are tabulated in Table 3-3.

3.3.2 Storage Inflows and Salinity

Inflows to all storages were estimated from an area/flow correlation using gauged inflows into the storage or in an adjacent catchment.

The correlation formula used was as follows:

QA=FC x FR x (AA/AG x QG) Where: QA – Total estimated inflow in ML/d

FC = Calibration Factor

FR = Rainfall adjustment factor

AA = Total Area of catchment to be estimated in Ha

AG = Area of gauged catchment in Ha


QG = Flow in gauged catchment in ML/d

and

FR = (MARA/MARG ) x MAFG Where: MAFG = mean annual flow in gauged catchment in ML

MARG = Mean annual rainfall in gauged catchment in ML

MARA = mean annual rainfall in Catchment A in ML

The mean annual rainfall for each catchment was obtained from regional rainfall maps (Bureau of Meteorology, 2003).

Parameters used to estimate the inflows to each storage are detailed in Table 3-4.

Table 3-4: Rainfall Adjustment and Calibration Factors

Storage Inflow

Catchment Area

(sq km)

Rainfall Adjustment

FR

Calibration Factor

FC

Lake Colac 216

Spiers Regulator 15

Lower Lough 23

Middle Lough 71

Upper Lough 21

The Sanctuary 55

1.00 1.05 (1974 – 1992) 0.88 (1993 – 2002)

Lake Corangamite 1105 0.77 – 0.83 0.60 (1974 – 1985) 0.95 (1986 – 2002)

Lake Gnarpurt 632 0.77 0.80

Cundare Pool & Lake Martin 192 0.77 0.80

Black Bridge Pool 1176 1.00 1.00

The salinity of all storage inflows was based on gauged data and regressions according to the equation described above for Barwon River analyses

Table 3-5 shows the regression coefficients for each of the catchments of the Lakes Colac and Corangamite. For Lake Colac and the northern sub-catchments of Lake Corangamite, Lake Martin and Lake Gnarpurt, there was sufficient salinity data to be able to extrapolate a regression from the gauged data. However in relation to the southern area of Lake Corangamite, there was insufficient salinity data associated with gauge GS 234203, the gauge used to calculate the inflows. Therefore, the


geographically closest gauge was used to extrapolate salinity data. It is assumed that the similarities in geology and rainfall patterns would create similarities in salinity.

Table 3-5: Storage Inflow Salinity (EC) Coefficients

Storage Inflow Correlated Site A B

Lake Colac

Spiers Regulator

Lower Lough

Middle Lough

Upper Lough

The Sanctuary

GS 234209 1573.3 -0.1393

Lake Corangamite GS 234209

GS 234201

1573.3

6071.5

-0.1393

-0.2295

Lake Gnarpurt

Cundare Pool & Lake Martin

GS 234201 6071.5 -0.2295

Black Bridge Pool GS 234200 2617 -0.1655

3.3.2 EC-TDS conversion

The IQQM model requires salinity inputs in terms of Total Dissolved Solids (TDS) in mg/L. Much of the available salinity data was available as Electrical Conductivity (EC) in units of microsiemens/cm. A conversion factor of 0.7 was applied to all EC data to arrive at estimates of TDS. This was derived from the previous investigations by RWC (Adams, 1990)

3.3.3 Groundwater Inflows

A desktop review of the hydrogeology within the region was undertaken. Results from this assessment were used to derive groundwater inflows in the model. The parameters used to quantify the flow and salinity were then varied during the calibration process to assist with the overall matching of flows and salinity with recorded values.

Specific groundwater inputs were assessed at the following locations:

Lake Colac;

Lough Calvert Drainage Channel;

Birregurra Creek (added to streamflow input);

Barwon River upstream of Winchelsea (added to streamflow input);


Barwon River between Winchelsea and Inverleigh (added to streamflow input);

Lake Corangamite;

Cundare Pool; and

Warrambine Creek (added to streamflow input).

In the final modelling, groundwater inputs to the streamflow inputs for Birregurra Creek, Barwon River and Warrambine Creek were not used in order to simplify the drainage scheme model. Groundwater interactions with the waterways is included in the gauged data and in the adopted model, tributary groundwater inflows were not used.

The equation used to determine groundwater flows was:

ΣQn= FG * Σ(Dn Kn (Hn2 – hn2)/2Ln)

Where: Q = groundwater discharge in m3/day,

K = Horizontal hydraulic conductivity in m/day,

H = Height of the water table at the groundwater divide in m AHD,

‘h = Height of the surface water in m AHD,

L = Distance between the groundwater divide and the surface water in m,

D = Length of the reach along which groundwater is discharging in m, and

‘n = the nth soil type.

FG = inflow calibration parameter

As these parameters vary for each soil type, this equation is applied for each of n soil types and each soil type discharge summed to find the overall discharge into the stream reach or storage.

The parameters for each modelled input are given in Table 3-6. The volume – inflow relationship derived for Lake Corangamite and Lake Colac are shown in Table 3-7. A constant 2 ML/d groundwater loss was adopted for Cundare Pool. This value was derived during the calibration.

Groundwater salinity was obtained from concentrations measured in adjacent bores. Where the bore salinities comprised a range of values, the mean was adopted. However, where the range of concentrations appeared without pattern, then the median was adopted.

A more detailed discussion of the results of the groundwater assessment is provided in Appendix D.

25


Table 3-6: Groundwater Parameters

Reach Soil Types K (m3/d)

H (m/d)

h (mAHD)

D (m)

L (m)

TDS (mg/L)

Quaternary Sands 1 114 7611 2000 5250 Lake Colac

Stony Rises 5 120

Varies with Storage Height 10089 4000 2100

Lough Calvert Channel Quaternary Sands 1 114 110 24000 1000 1400

Stony Rises 8 118 51975 2000 4200

Basalt Plains 2 118 8025 2000 7000 Lake Corangamite

Tertiary Sands 5 118

Varies with changes in Lake height

15000 2000 7000

Quaternary Sands 1 110 10000 1500 7000

Basalt Plains 2 110 10000 1500 7000 Cundare Pool


Varies with storage height

10000 1500 7000


Table 3-7: Groundwater Inflows

Lake Corangamite (FG = 1) Lake Colac (FG = 1.2)

Volume (ML) Inflow (ML/d) Volume (ML) Inflow (ML/d)

100,000 157.8 5,000 16.7

150,000 149.7 10,000 16.2

200,000 141.7 15,000 15.7

250,000 133.7 20,000 15.2

300,000 126.7 35,000 13.4

350,000 119.6 62,000 11.4

400,000 112.5 76,000 10.4

450,000 105.7 78,000 10.2

500,000 99.1 80,000 10.0

550,000 92.6

600,000 86.2

650,000 79.8

700,000 73.6

750,000 67.5

800,000 61.2

850,000 54.8

900,000 49.2

950,000 43.5

1,000,098 37.5

1,050,000 31.9

1,100,000 26.0

1,150,000 21.2

1,200,000 16.6

1,250,000 12.0

1,300,000 7.4

1,350,000 2.8

1,400,000 0.0

1,860,000 0.0


3.4 Irrigation Data Extractions for irrigation were included at three locations in the model. These locations were:

Barwon River upstream of Winchelsea;

Barwon River between Winchelsea and Inverleigh; and

Barwon River between Inverleigh and Leigh River.

There were no historical records available for irrigation extractions along the Barwon River within the study area. Extractions were therefore estimated using annual licensed volumes. Licensed volumes were obtained from SKM (2003).

To convert the annual volumes to daily records, a monthly distribution factor was applied to the annual licence volume for each reach along the Barwon River to prepare the irrigation extraction time series. The monthly distribution factor was based on perennial pasture and potatoes being the predominant crop types in the area. Hence, extractions were assumed to occur between September and April in all years.

A special extraction for winter filling of farm dams was also included which was linked to the 14 day shut down of the Lough Calvert Drainage Scheme in May/June.

A summary of the licence volumes and monthly distribution factor is provided in Table 3-8 and Table 3-9.

Table 3-8: Irrigation Licence Volumes along the Barwon River

Reach

Licensed Volume Winter Fill

Barwon River upstream of Winchelsea 194 ML/a NA

Barwon River between Winchelsea and Inverleigh, and 124 ML/a 76 ML/a

Barwon River between Inverleigh and Leigh River. 99 ML/a NA


Table 3-9: Monthly Irrigation Extraction Factors

Month Distribution Factor

January 5%

February 5%

March 20%

April 20%

May- August 0%

September 20%

October 20%

November 5%

December 5%

3.5 Operation Rules Releases into the Lough Calvert Drainage Channel and the Woady Yaloak Drainage Channel were regulated in accordance with current operation rules for each scheme. The current rules were used for the entire modelling period and are described below.

3.5.1 Woady Yaloak Diversion Channel (WYDC) Operational Rules

The rules are defined in detail in “Operating Instructions for the Woady Yaloak River (Lake Corangamite) Diversion Scheme” (Rural Water Commission, 1987). There has been no change to the operational rules since the commissioning of the scheme in 1959.

Allowable Period of Release: All Year

Salinity Constraints: Measured at Barwon River @ d/s Leigh River Confluence

Nov – Mar 2000 EC (1400mg/L)

Apr 2200 EC (1540mg/L)

May 3500 EC (2450mg/L)

Jun 4500 EC (3150mg/L)

Jul – Aug 5200 EC (3640mg/L)

Sep 4500 EC (3150mg/L)

Oct 2500 EC (1750mg/L)

Other: No salinity limits in Lake Corangamite apply


3.5.2 Lough Calvert Drainage Channel (LCDC) Operational Rules

The system is operated within the constraints of the operating rules. The main purpose of the operating rules is to minimise the impact of the scheme control on salinity in the Barwon River. The current operating rules are detailed below. The operational rules have been formally changed once, following a review by Johnson et al in 1992. These changes were adopted in 1994.

The current rules (ie post 1994) were implemented in the model and applied over the entire modelling period.

Allowable Period of Release: 1 May - 30 October

Salinity Constraints: Measured at Barwon River @ Winchelsea

May – Jun 1700 EC (1190 mg/L)

July – Sep 2500 EC (1750 mg/L)

Oct 1700 EC (1190 mg/L)

Other: No salinity limits in Lake Colac

Releases are not permitted unless lake level is greater than 116.6m

Scheme to be shut down for 14 days during May & June to provide better water quality for the filling of dams, provided flows in Barwon are greater than 250 ML/d

Target level curve for Lake Colac to be adopted (refer below)


4. Model Calibration and Validation

4.1 Introduction The simulation model was calibrated over the period 1986 to 2002. Calibration “parameters” were taken to be:

Surface water runoff factor Fc (varied with time);

Groundwater inflow factor FG (varied between storages);

Regulator capacities (difference between nominal capacity and actual measured capacities); and

Stage discharge relationship between Cundare Pool and Lake Corangamite.

Verification was undertaken for the period from 1974 to 2002 without parameter adjustment.

The calibration involved a detailed assessment and comparison of recorded and modelled results at the following locations in the model:

Lake Colac (level and salinity);

Lake Corangamite (level and salinity);

Cundare Pool (level and salinity);

Lough Calvert Drainage Channel Releases;

Woady Yaloak Drainage Channel Releases;

Barwon River @ Inverleigh (flow and salinity); and

Barwon River @ Pollocksford (flow and salinity).

Due to the lack of recorded data, there has been no specific calibration attempted at the Loughs, the Sanctuary, Lake Gnarpurt and Lake Murdeduke. However, a qualitative check was undertaken for these storages based on anecdotal information.

The calibration process also included a comparison of annual flow and annual salt loads at several locations.

Section 4.2 provides charts and comments on the results from the calibration model.

4.2 Model Calibration 1986 – 2002 Lake Colac Levels, Salinity, Level/Duration – Figure 4-1

Lake Colac storage levels are simulated reasonably well by the model. The levels are very sensitive to changes in surface water and groundwater inflows. Two specific periods appear to significantly affect the calibration, as follows:

May 1997 to October 1997 – Storage levels are significantly underestimated during this period, and consequently results in the underestimation of levels for the period to December 2000. This mis-match can be attributed to the scheme not being operated in accordance with the release triggers during this period.


However, the model does activate releases during this period, as per the release trigger criteria.

August 2001 to December 2001 – The model overestimates storage levels during this period. It appears that this may be attributable to the over-estimation of groundwater inflows during this period, despite groundwater inflows being approximated reasonably well during other periods when the storage is between 30,000 ML and 40,000 ML capacity. It may be possible that groundwater inflows have been influenced by the dry conditions between 1997 and 2002, which cannot be incorporated into the current groundwater inflow estimates, because of the lack of available information.

The model consistently over estimates salinity in Lake Colac. This can be partly attributed to the general under-estimation of storage levels.

The level duration results show that the model simulates storage levels above 50,000 ML (EL 116.60). Level estimation below 50,000 ML has been significantly influenced by the releases in 2002, which is described above.

Lake Corangamite Levels, Salinity, Level/Duration - Figure 4-2

Lake Corangamite storage levels are simulated well by the model. It was found that lake levels are very sensitive to inflows from groundwater, Lake Gnarpurt and Cundare Pool. The Level/Duration analysis also confirm the relative accuracy of the storage level simulation.

Salinity in Lake Corangamite is also represented well by the model.

Cundare Pool Levels, Salinity Figure 4-3

There was very limited calibration data available for Cundare Pool, in particular, the records of flow from Cundare Pool to Lake Corangamite. However, the figure shows that the model simulates the storage levels reasonably well. It is noted that simulated levels are lower than modelled levels between November 1997 and December 2002. It is believed that this is because releases into the Woady Yaloak Drainage Channel did not occur over this period to enable Cundare Pool levels to be increased for environmental purposes. This change in the scheme operation was not modelled.


Figure 4-1– Lake Colac Calibration (1986 – 2002)

L ak e C o la c - S to ra g e L e ve ls

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Lake Colac - Level Duration Analysis

NO RM AL LEVEL 50,000M L (EL 116.60)

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Figure 4-2 – Lake Corangamite Calibration (1986 – 2002)

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Lake Corangam ite - Level Duration Analysis

NO RMAL LEVEL 540,000M LEL 114.71

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Figure 4-3 – Cundare Pool Calibration (1986 – 2002)

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Lough Calvert Drainage Channel Releases, Salinity Figure 4-4

This figure shows a comparison of flows and salinity from Warrowie Regulator. The flow results show that the timing of releases being implemented in the model is consistent with historical records. Annual diversion volumes were generally found to be consistent with recorded data, whilst the annual salt load diverted tends to be overestimated by the model. This is attributable to the overestimation of salinity concentrations in Lake Colac. Recorded salinity data at Warrowie regulator comprised diary entries from operators handbooks. This information could not be used for calibration, but may be suitable for examining specific management options associated with this part of the system.

The model also indicates zero salinity when no flows are being released on the channel. However, in practice salinity monitoring could occur for water in the channel even though there may be no flow.

Woady Yaloak Drainage Channel Releases, Salinity Figure 4-5

The model has been set up to divert flows from the Woady Yaloak River, whenever the salinity criterion in the Barwon River is met. The model appears to simulate the timing of releases well, however flow volumes tend to be overestimated. It would appear that in practice, low flows in the Woady Yaloak River between December and May are not diverted into the channel, and instead these flows are diverted into Cundare Pool. As there are no operational procedures or targets for Cundare Pool, this has not been accounted for in the model.

Lough Calvert Drainage Channel Trigger - Figure 4-6

This figure demonstrates the implementation of the salinity triggers for releases from Lake Colac into the Lough Calvert Drainage Channel, in accordance with the operating rules for the scheme.

The salinity “spikes” that are evident in the 1986 – 2002 chart are a result of model instabilities, which occur when streamflow is extremely small.

The 1993 chart shows that releases occur between May and October, and only when salinity level at Winchelsea is below the nominated trigger level. It is recognised that in practice, the scheme is operated on a more intuitive basis than can be modelled, which includes predictions on the likely impact on the Barwon River. This practice eliminates the scheme being turned on and off as is shown in the 1993 figure during May and June.

Woady Yaloak Drainage Channel Trigger Figure 4-7

This figure demonstrates the implementation of the salinity triggers for diversions from the Woady Yaloak River into the Woady Yaloak Drainage Channel, in accordance with the operating rules for the scheme.


Figure 4-4 – Lough Calvert Drainage Channel Calibration (1986 – 2002)

Warrowie Regulator - Flow Summary

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Figure 4-5 – Woady Yaloak Drainage Channel Calibration (1986 – 2002)

WYDC - Flow Summary

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300

400

500

600

01/0

1/19

86

01/0

1/19

87

01/0

1/19

88

31/1

2/19

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31/1

2/19

89

31/1

2/19

90

31/1

2/19

91

30/1

2/19

92

30/1

2/19

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30/1

2/19

94

30/1

2/19

95

29/1

2/19

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29/1

2/19

97

29/1

2/19

98

29/1

2/19

99

28/1

2/20

00

28/1

2/20

01

28/1

2/20

02

Flow

(ML/

day)

Modelled Flow

Recorded Flow

WYDC - Salinity Summary (1986 - 2002)

0

1000

2000

3000

4000

5000

6000

7000

8000

01/0

1/19

86

01/0

1/19

87

01/0

1/19

88

31/1

2/19

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31/1

2/19

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31/1

2/19

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31/1

2/19

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30/1

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30/1

2/19

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30/1

2/19

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30/1

2/19

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29/1

2/19

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29/1

2/19

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29/1

2/19

99

28/1

2/20

00

28/1

2/20

01

28/1

2/20

02

Salin

ity (m

g/L)

Modelled Salinity

Recorded Salinity


Figure 4-6 – Lough Calvert Drainage Channel Trigger

LCDC Trigger Verification (1993)

-400

-300

-200

-100

0

100

200

300

400

500

01/0

1/19

93

31/0

1/19

93

02/0

3/19

93

01/0

4/19

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01/0

5/19

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31/0

5/19

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30/0

6/19

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30/0

7/19

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29/0

8/19

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28/0

9/19

93

28/1

0/19

93

27/1

1/19

93

27/1

2/19

93

Flow

(ML/

day)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Salin

ity (m

g/L)

Modelled FlowFlow @ WinchelseaSalinity @ WinchelseaTrigger Salinity

LCDC Trigger Verification (1986 - 2002)

-400

-300

-200

-100

0

100

200

300

400

500

01/0

1/19

86

01/0

1/19

87

01/0

1/19

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31/1

2/19

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31/1

2/19

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31/1

2/19

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31/1

2/19

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30/1

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30/1

2/19

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30/1

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2/19

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29/1

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2/19

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29/1

2/19

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28/1

2/20

00

28/1

2/20

01

28/1

2/20

02

Flow

(ML/

day)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Salin

ity (m

g/L)

Modelled Flow

Flow @ Winchelsea

Salinity @ W inchelsea


Figure 4-7 – Woady Yaloak Drainage Channel Trigger

WYDC Trigger Verification (1986 to 2002)

-300

-200

-100

0

100

200

300

400

500

600

01/0

1/19

86

01/0

1/19

87

01/0

1/19

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31/1

2/19

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31/1

2/19

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31/1

2/19

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2/19

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29/1

2/19

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28/1

2/20

00

28/1

2/20

01

28/1

2/20

02

Flow

(ML/

day)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Salin

ity (m

g/L)

Flow @ D/S Leigh R

Modelled Flow

Salinity @ D/S Leigh R

WYDC Trigger Verification (1993)

-300

-200

-100

0

100

200

300

400

500

600

01/0

1/19

93

31/0

1/19

93

02/0

3/19

93

01/0

4/19

93

01/0

5/19

93

31/0

5/19

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30/0

6/19

93

30/0

7/19

93

29/0

8/19

93

28/0

9/19

93

28/1

0/19

93

27/1

1/19

93

27/1

2/19

93

Flow

(ML/

day)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Salin

ity (m

g/L)

Modelled Flow

Flow @ D/S Leigh R

Salinity @ D/S Leigh R

Salinity Trigger


Barwon River @ Inverleigh - Figure 4-8 and Figure 4-9

These figures demonstrate that the model simulates flow and salinity in the Barwon River at Inverleigh, particularly during the critical period from June to October inclusive. The 1993 flow chart demonstrates the implementation of the flow routing included in the model which tends to attenuate and delay the flows. This also attenuates the salinities as shown on the salinity graph.

The 1986 to 2002 salinity chart has been plotted using the average monthly salinity. Daily salinity results show numerous salinity “spikes”, which are a result of instabilities in the model (usually) when streamflows are extremely low. These spikes do not have any impact on salt load estimates and, as shown, are eliminated when monthly average results are reported.

The salinity duration chart shows that salinity concentration tends to be overestimated by the model at this location.

Barwon River @ Pollocksford – Figure 4-10 and Figure 4-11

Flows are represented well by the model since the majority of the flow is input information rather than model results. The 1986 to 2002 salinity chart has also been plotted using monthly average concentrations, which compares reasonably well with recorded information. Daily salinity values are a little inconsistent with recorded data and contain several salinity spikes, similar to the Inverleigh results. This may also be a result of the simplistic treatment of tributary flows, and will be examined further during the modelling of system options.

The salinity duration chart shows that salinity concentration is modelled reasonable well by the model at this location.

4.3 Annual Volumes and Salt Loads Annual flow volumes and salt loads from the model results are presented in Table 4-1. These results will be beneficial when comparing management options and to identify the relative contributions of various sources to flow and salt.

The “recorded” values presented in this table were derived from recorded daily flow and salinity values at the specified location. “Modelled” values have also been derived from daily flow and salinity estimates obtained from the model.

41


Figure 4-8 – Barwon River @ Inverleigh Calibration

Barwon R @ Inverleigh - Flow Summary (1993)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

01/0

1/19

93

31/0

1/19

93

02/0

3/19

93

01/0

4/19

93

01/0

5/19

93

31/0

5/19

93

30/0

6/19

93

30/0

7/19

93

29/0

8/19

93

28/0

9/19

93

28/1

0/19

93

27/1

1/19

93

27/1

2/19

93

Flow

(ML/

day)

Modelled Flow

Recorded Flow

Barwon R @ Inverleigh - Salinity Summary (1993)

0

1000

2000

3000

4000

5000

6000

01/0

1/19

93

31/0

1/19

93

02/0

3/19

93

01/0

4/19

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01/0

5/19

93

31/0

5/19

93

30/0

6/19

93

30/0

7/19

93

29/0

8/19

93

28/0

9/19

93

28/1

0/19

93

27/1

1/19

93

27/1

2/19

93

Salin

ity (m

g/L)

Modelled Salinity

Recorded Salinity

Barwon R @ Inverleigh - Flow Summary (1986 to 2002)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

01/0

1/19

86

01/0

1/19

87

01/0

1/19

88

31/1

2/19

88

31/1

2/19

89

31/1

2/19

90

31/1

2/19

91

30/1

2/19

92

30/1

2/19

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30/1

2/19

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30/1

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29/1

2/19

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29/1

2/19

98

29/1

2/19

99

28/1

2/20

00

28/1

2/20

01

28/1

2/20

02

Flow

(ML/

day)

Modelled Flow

Recorded Flow

Barwon R @ Inverleigh - Salinity Summary (1986 to 2002)

0

1000

2000

3000

4000

5000

6000

01/0

1/19

86

01/0

1/19

87

01/0

1/19

88

31/1

2/19

88

31/1

2/19

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31/1

2/19

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31/1

2/19

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30/1

2/19

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30/1

2/19

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30/1

2/19

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30/1

2/19

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29/1

2/19

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29/1

2/19

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29/1

2/19

98

29/1

2/19

99

28/1

2/20

00

28/1

2/20

01

28/1

2/20

02

Salin

ity (m

g/L)

Modelled Salinity

Recorded Salinity


Figure 4-9 – Barwon River @ Inverleigh Calibration

Barwon River @ Inverleigh - Flow Duration Analysis (1986 - 2002)

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Time Exceeded

Flow

(ML/

d)

Recorded

Modelled

Barwon River @ Inverleigh - Salinity Duration Analysis (1994 - 2002)

0

2,000

4,000

6,000

8,000

10,000

12,000

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Time Exceeded

Salin

ity (m

g/L)

Recorded

Modelled

43


Figure 4-10 – Barwon River @ Pollocksford Calibration

Barw on R @ Pollocksford - Flow Sum m ary

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

01/0

1/19

86

01/0

1/19

87

01/0

1/19

88

31/1

2/19

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31/1

2/19

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31/1

2/19

90

31/1

2/19

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30/1

2/19

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30/1

2/19

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30/1

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30/1

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29/1

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29/1

2/19

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29/1

2/19

99

28/1

2/20

00

28/1

2/20

01

28/1

2/20

02

Flow

(ML/

day)

M odelled F low

R ecorded Flow

B arw on R @ Pollocksford - Salinity Sum m ary

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

01/0

1/19

86

01/0

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31/1

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31/1

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28/1

2/20

00

28/1

2/20

01

28/1

2/20

02

Salin

ity (m

g/L)

Modelled Salinity

Recorded Salinity

Barw on R @ Pollocksford - Flow Sum m ary (1995)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

01/0

1/19

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28/0

9/19

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28/1

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95

27/1

1/19

95

27/1

2/19

95

Flow

(ML/

day)

M odelled F low

Recorded Flow

Barw on R @ Pollocksford - Salinity Sum m ary (1995)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

01/0

1/19

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31/0

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02/0

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30/0

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8/19

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9/19

95

28/1

0/19

95

27/1

1/19

95

27/1

2/19

95

Salin

ity (m

g/L)

Modelled Salinity

Recorded Salinity


Figure 4-11 – Barwon River @ Pollocksford Calibration

Barwon River @ Pollocksford - Flow Duration Analysis (1986 - 2002)

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Time Exceeded

Flow

(ML/

d)

Recorded

Modelled

Barwon River @ Pollocksford - Salinity Duration Analysis (1994 - 2002)

0

1,000

2,000

3,000

4,000

5,000

6,000

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%% Time Exceeded

Salin

ity (m

g/L)

Recorded

Modelled

45


Table 4-1: Annual Flow and Salt Load Comparison

Inverleigh Flow (ML) Pollocksford Flow (ML) Inverleigh Salt Load (t) Pollocksford Salt Load (t)

Recorded Modelled Recorded Modelled Recorded Modelled Recorded Modelled

1986 147,580 165,454 251,286 250,878 83,469 139,069 NA 218,029

1987 105,171 126,316 184,820 189,887 69,627 127,090 NA 183,095

1988 48,626 47,997 110,275 95,879 39,072 42,195 NA 84,575

1989 161,492 170,372 327,132 309,003 76,400 130,074 NA 270,050

1990 111,350 126,398 218,464 219,067 79,870 141,634 NA 218,238

1991 163,133 179,948 258,477 267,392 119,319 187,218 NA 260,392

1992 206,225 231,517 370,585 419,271 139,712 219,265 NA 388,694

1993 126,960 147,520 261,352 267,544 92,125 147,310 NA 236,022

1994 46,283 62,863 81,923 85,821 49,195 78,032 79,147 124,064

1995 197,987 215,691 347,519 335,880 103,729 162,879 199,635 373,150

1996 143,367 158,669 297,708 283,420 81,607 105,160 170,999 211,190

1997 24,293 28,809 42,116 46,526 22,597 33,542 51,673 60,388

1998 33,455 32,841 51,324 54,019 23,954 28,347 52,519 58,636

1999 10,059 9,334 27,575 26,685 14,513 9,110 39,105 33,234

2000 41,702 41,140 84,773 83,575 28,580 30,594 76,723 77,052

2001 140,385 140,037 190,367 211,677 70,356 107,571 128,788 226,715

2002 40,949 40,400 55,537 59,590 31,854 31,388 60,437 60,437


4.4 Model Verification 1974 – 2002 The verification model was run from 1974 to 2002. Due to the lack of verification data, the comparison of recorded and modelled results was limited to the following locations:

Lake Colac (level);

Lake Corangamite (level);

Barwon River @ Inverleigh (flow); and

Barwon River @ Pollocksford (flow).

The verification run shows that the model is able to predict variables at key locations for the whole period of record since 1974.


Figure 4-12 – Lake Colac and Lake Corangamite Verification

Lake Colac - Storage Levels (1974 - 2002)

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

01/0

1/19

74

01/0

1/19

75

01/0

1/19

76

31/1

2/19

76

31/1

2/19

77

31/1

2/19

78

31/1

2/19

79

30/1

2/19

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30/1

2/19

81

30/1

2/19

82

30/1

2/19

83

29/1

2/19

84

29/1

2/19

85

29/1

2/19

86

29/1

2/19

87

28/1

2/19

88

28/1

2/19

89

28/1

2/19

90

28/1

2/19

91

27/1

2/19

92

27/1

2/19

93

27/1

2/19

94

27/1

2/19

95

26/1

2/19

96

26/1

2/19

97

26/1

2/19

98

26/1

2/19

99

25/1

2/20

00

25/1

2/20

01

25/1

2/20

02

Stor

age

Volu

me

(ML)

Modellled Levels

Recorded Levels

Lake Corangamite - Storage Levels (1974 - 2002)

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

01/0

1/19

74

01/0

1/19

75

01/0

1/19

76

31/1

2/19

76

31/1

2/19

77

31/1

2/19

78

31/1

2/19

79

30/1

2/19

80

30/1

2/19

81

30/1

2/19

82

30/1

2/19

83

29/1

2/19

84

29/1

2/19

85

29/1

2/19

86

29/1

2/19

87

28/1

2/19

88

28/1

2/19

89

28/1

2/19

90

28/1

2/19

91

27/1

2/19

92

27/1

2/19

93

27/1

2/19

94

27/1

2/19

95

26/1

2/19

96

26/1

2/19

97

26/1

2/19

98

26/1

2/19

99

25/1

2/20

00

25/1

2/20

01

25/1

2/20

02

Stor

age

Volu

me

(ML)

Modellled Levels

Recorded Levels

48


Figure 4-13 – Barwon River Verification

Barwon R @ Inverleigh - Flow Summary (1974 to 2002)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

01/0

1/19

74

01/0

1/19

75

01/0

1/19

76

31/1

2/19

76

31/1

2/19

77

31/1

2/19

78

31/1

2/19

79

30/1

2/19

80

30/1

2/19

81

30/1

2/19

82

30/1

2/19

83

29/1

2/19

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29/1

2/19

85

29/1

2/19

86

29/1

2/19

87

28/1

2/19

88

28/1

2/19

89

28/1

2/19

90

28/1

2/19

91

27/1

2/19

92

27/1

2/19

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27/1

2/19

94

27/1

2/19

95

26/1

2/19

96

26/1

2/19

97

26/1

2/19

98

26/1

2/19

99

25/1

2/20

00

25/1

2/20

01

25/1

2/20

02

Flow

(ML/

day)

Modelled Flow

Recorded Flow

Barwon R @ Pollocksford - Flow Summary (1974 - 2002))

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

01/0

1/19

74

01/0

1/19

75

01/0

1/19

76

31/1

2/19

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31/1

2/19

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31/1

2/19

78

31/1

2/19

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30/1

2/19

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30/1

2/19

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30/1

2/19

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30/1

2/19

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29/1

2/19

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29/1

2/19

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29/1

2/19

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29/1

2/19

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28/1

2/19

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28/1

2/19

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28/1

2/19

90

28/1

2/19

91

27/1

2/19

92

27/1

2/19

93

27/1

2/19

94

27/1

2/19

95

26/1

2/19

96

26/1

2/19

97

26/1

2/19

98

26/1

2/19

99

25/1

2/20

00

25/1

2/20

01

25/1

2/20

02

Flow

(ML/

day)

Modelled Flow

Recorded Flow

B arw on R @ Inverle ig h - F low S um m ary (1975)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

01/0

1/19

75

31/0

1/19

75

02/0

3/19

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01/0

4/19

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01/0

5/19

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31/0

5/19

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7/19

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8/19

75

28/0

9/19

75

28/1

0/19

75

27/1

1/19

75

27/1

2/19

75

Flow

(ML/

day)

M ode lled F low

R eco rded F low

B arw on R @ P ollocksford - F low S um m ary (1975)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

01/0

1/19

75

31/0

1/19

75

02/0

3/19

75

01/0

4/19

75

01/0

5/19

75

31/0

5/19

75

30/0

6/19

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30/0

7/19

75

29/0

8/19

75

28/0

9/19

75

28/1

0/19

75

27/1

1/19

75

27/1

2/19

75

Flow

(ML/

day)

M od elle d F low

R ecorded F low


5. Conclusion

This report demonstrates that while there are a number of minor inconsistencies, the model provides a good simulation of recorded data at key locations required for comparative analysis of scheme operation alternatives. It is anticipated that some further fine-tuning of the calibration model will be required when further detailed assessment of the specific scheme operation alternatives is undertaken.

These key “fits” with recorded data are:

Level (volume) and salinity at Lake Corangamite;

Level (volume) and salinity at Lake Colac; and

Flow to salinity duration in the Barwon River at Inverleigh and Pollocksford.


6. Abbreviations and Units of Measure

6.1 Abbreviations GHD GHD Pty Ltd. Engineering Consultancy

RWC Rural Water Commission of Victoria

SR&WSC State Rivers and Water Supply Commission of Victoria

CCMA Corangamite Catchment Management Authority

TDS Total Dissolved Solids in milligrams per litre (mg/L)

EC Salinity concentration in µsm/cm

6.2 Units and Conversions mg/L Milligrams per litre (also equivalent to kg/ML)

ML/d Mega-Litres per day

µs/cm microsiemens per centimetre

t metric tonne (equal to 1,000 kg)

TDS = EC * 0.7

1 ML = 1,000 m3


7. References

Adams, G (1990), Corangamite Review Technical Report – A Report on Analyses Conducted by the Rural Water Commission for the Drainage Schemes Review, March 1990.

Bureau of Meteorology (2003), http://www.bom.gov.au/cgi-bin/ climate/cgi_bin_scripts/annual_rnfall.cgi

DLWC (2000), IQQM User Manual – Win32 GUI Version.

GHD (2003a), Background Report – Corangamite Drainage Schemes Review, Corangamite Catchment Management Authority.

GHD (2003b), Community Consultation Report, – Corangamite Drainage Schemes Review, Corangamite Catchment Management Authority.

GHD (2003c), Model Scoping Report, – Corangamite Drainage Schemes Review, Corangamite Catchment Management Authority.

Johnson, K (1992), Lake Colac and Lough Calvert Drainage Scheme - Review of Operating Rules.

RWC (1988), South West Region Water Resources Managemnet Study, Project Report for Corangamite Basin Drainage Schemes Review, Rural Water Commission Investigations Branch Report No. 1988/23 July 1988.

SKM (2003), Lower Barwon REALM Model, Southern Rural Water, Final 1, January 2003.

SR&WSC (1979), Lake Colac-Lough Calvert Flood Mitigation Report, State Rivers and Water Supply Commission, July 1979.


Appendix A

Locality Plan

LakeLakeLakeLakeLakeLakeLakeLakeLakeBeeacBeeacBeeacBeeacBeeacBeeacBeeacBeeacBeeac

Lake MartinLake MartinLake MartinLake MartinLake MartinLake MartinLake MartinLake MartinLake Martin

Lake OnditLake OnditLake OnditLake OnditLake OnditLake OnditLake OnditLake OnditLake Ondit

Lake RosineLake RosineLake RosineLake RosineLake RosineLake RosineLake RosineLake RosineLake Rosine

Lake ColacLake ColacLake ColacLake ColacLake ColacLake ColacLake ColacLake ColacLake Colac

Lake WeeringLake WeeringLake WeeringLake WeeringLake WeeringLake WeeringLake WeeringLake WeeringLake Weering

GS 233702GS 233702GS 233702GS 233702GS 233702GS 233702GS 233702GS 233702GS 233702















GS 234211GS 234211GS 234211GS 234211GS 234211GS 234211GS 234211GS 234211GS 234211GS 234202GS 234202GS 234202GS 234202GS 234202GS 234202GS 234202GS 234202GS 234202

















GS 233211GS 233211GS 233211GS 233211GS 233211GS 233211GS 233211GS 233211GS 233211GS 233247GS 233247GS 233247GS 233247GS 233247GS 233247GS 233247GS 233247GS 233247









Lake CorangamiteLake CorangamiteLake CorangamiteLake CorangamiteLake CorangamiteLake CorangamiteLake CorangamiteLake CorangamiteLake Corangamite

Lake GnarpurtLake GnarpurtLake GnarpurtLake GnarpurtLake GnarpurtLake GnarpurtLake GnarpurtLake GnarpurtLake Gnarpurt

Lake CundareLake CundareLake CundareLake CundareLake CundareLake CundareLake CundareLake CundareLake Cundare

Lake MurdedukeLake MurdedukeLake MurdedukeLake MurdedukeLake MurdedukeLake MurdedukeLake MurdedukeLake MurdedukeLake Murdeduke

INVERLEIGHINVERLEIGHINVERLEIGHINVERLEIGHINVERLEIGHINVERLEIGHINVERLEIGHINVERLEIGHINVERLEIGH

WINCHELSEAWINCHELSEAWINCHELSEAWINCHELSEAWINCHELSEAWINCHELSEAWINCHELSEAWINCHELSEAWINCHELSEA

COLACCOLACCOLACCOLACCOLACCOLACCOLACCOLACCOLAC

WOADYWOADYWOADYWOADYWOADYWOADYWOADYWOADYWOADY

YALOAK

YALOAK

YALOAK

YALOAK

YALOAK

YALOAK

YALOAK

YALOAK

YALOAK

DIVERSION

DIVERSION

DIVERSION

DIVERSION

DIVERSION

DIVERSION

DIVERSION

DIVERSION

DIVERSIONCHANNEL

CHANNEL

CHANNEL

CHANNEL

CHANNEL

CHANNEL

CHANNEL

CHANNEL

CHANNEL

LOWERLOWERLOWERLOWERLOWERLOWERLOWERLOWERLOWERLOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGH

THETHETHETHETHETHETHETHETHESANCTUARYSANCTUARYSANCTUARYSANCTUARYSANCTUARYSANCTUARYSANCTUARYSANCTUARYSANCTUARY

UPPERUPPERUPPERUPPERUPPERUPPERUPPERUPPERUPPERLOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGH

MIDDLEMIDDLEMIDDLEMIDDLEMIDDLEMIDDLEMIDDLEMIDDLEMIDDLELOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGHLOUGH

BIRREGURRA

BIRREGURRA

BIRREGURRA

BIRREGURRA

BIRREGURRA

BIRREGURRA

BIRREGURRA

BIRREGURRA

BIRREGURRACREEKCREEKCREEKCREEKCREEKCREEKCREEKCREEKCREEK

BARWONBARWONBARWONBARWONBARWONBARWONBARWONBARWONBARWON

RIVERRIVERRIVERRIVER

RIVERRIVERRIVERRIVERRIVER

BARWON

BARWON

BARWON

BARWON

BARWON

BARWON

BARWON

BARWON

BARWONRIVERRIVERRIVER

RIVERRIVER

RIVERRIVERRIVER

RIVER

WARRAMBINE

WARRAMBINE

WARRAMBINE

WARRAMBINE

WARRAMBINE

WARRAMBINE

WARRAMBINE

WARRAMBINE

WARRAMBINE

CREEK

CREEK

CREEKCREEK

CREEKCREEK

CREEK

CREEKCREEK

LE

IGH

LE

IGH

LE

IGH

LE

IGH

LE

IGH

LE

IGH

LE

IGH

LE

IGH

LE

IGH

RIVERRIVERRIVER

RIVERRIVER

RIVERRIVERRIVER

RIVER

WO

ADYYALO

AKRIV

ER

WO

ADYYALO

AKRIV

ER

WO

ADYYALO

AKRIV

ER

WO

ADYYALO

AKRIV

ER

WO

ADYYALO

AKRIV

ER

WO

ADYYALO

AKRIV

ER

WO

ADYYALO

AKRIV

ER

WO

ADYYALO

AKRIV

ER

WO

ADYYALO

AKRIV

ER

CRESSYCRESSYCRESSYCRESSYCRESSYCRESSYCRESSYCRESSYCRESSY

Regional Drainage SchemeRegional Drainage SchemeRegional Drainage SchemeRegional Drainage SchemeRegional Drainage SchemeRegional Drainage SchemeRegional Drainage SchemeRegional Drainage SchemeRegional Drainage SchemeLocality PlanLocality PlanLocality PlanLocality PlanLocality PlanLocality PlanLocality PlanLocality PlanLocality Plan

Unsealed RoadsUnsealed RoadsUnsealed RoadsUnsealed RoadsUnsealed RoadsUnsealed RoadsUnsealed RoadsUnsealed RoadsUnsealed Roads

Sealed RoadsSealed RoadsSealed RoadsSealed RoadsSealed RoadsSealed RoadsSealed RoadsSealed RoadsSealed Roads

LoughsLoughsLoughsLoughsLoughsLoughsLoughsLoughsLoughs

Drains & ChannelsDrains & ChannelsDrains & ChannelsDrains & ChannelsDrains & ChannelsDrains & ChannelsDrains & ChannelsDrains & ChannelsDrains & Channels

Rivers & LakesRivers & LakesRivers & LakesRivers & LakesRivers & LakesRivers & LakesRivers & LakesRivers & LakesRivers & LakesStream GaugesStream GaugesStream GaugesStream GaugesStream GaugesStream GaugesStream GaugesStream GaugesStream Gauges

G:\31\12846\GIS\Locality Plan.WOR

Scale 1:200,000 at A3

StreamsStreamsStreamsStreamsStreamsStreamsStreamsStreamsStreamsGS 234614GS 234614GS 234614GS 234614GS 234614GS 234614GS 234614GS 234614GS 234614

ÿ

RegulatorRegulatorRegulatorRegulatorRegulatorRegulatorRegulatorRegulatorRegulator

Warrowee Cut RegulatorWarrowee Cut RegulatorWarrowee Cut RegulatorWarrowee Cut RegulatorWarrowee Cut RegulatorWarrowee Cut RegulatorWarrowee Cut RegulatorWarrowee Cut RegulatorWarrowee Cut Regulator

Spiers RegulatorSpiers RegulatorSpiers RegulatorSpiers RegulatorSpiers RegulatorSpiers RegulatorSpiers RegulatorSpiers RegulatorSpiers Regulator

Cundare PoolCundare PoolCundare PoolCundare PoolCundare PoolCundare PoolCundare PoolCundare PoolCundare Pool

Cundare BarrageCundare BarrageCundare BarrageCundare BarrageCundare BarrageCundare BarrageCundare BarrageCundare BarrageCundare Barrage

Blackpool BarrageBlackpool BarrageBlackpool BarrageBlackpool BarrageBlackpool BarrageBlackpool BarrageBlackpool BarrageBlackpool BarrageBlackpool Barrage


ModelledModelledModelledModelledModelledModelledModelledModelledModelled

Not ModelledNot ModelledNot ModelledNot ModelledNot ModelledNot ModelledNot ModelledNot ModelledNot Modelled


Appendix B

IQQM Files

IQQM File List File Name File

Type Comment

Barwon Inflows v3 Excel Barwon River inflows upstream of Birregurra Creek file Barwon Salinity v3 Excel Barwon River salinity upstream of Birregurra Creek file BarwonF Text Barwon River inflows upstream of Birregurra Creek file BarwonS Text Barwon River salinity upstream of Birregurra Creek file Barwon.flo IQQM Barwon River inflows upstream of Birregurra Creek file Barwon.slt IQQM Barwon River salinity upstream of Birregurra Creek file Bbridge.flo IQQM Black Bridge Pool inflows file Bbridge.slt IQQM Black Bridge Pool salinity file Birregurra Inflows v2 Excel Birregurra Creek inflows upstream of Lough Calvert

Channel file Birregurra Salinity v2 Excel Birregurra Creek salinity upstream of Lough Calvert

Channel file BirregF Text Birregurra Creek inflows upstream of Lough Calvert

Channel file BirregS Text Birregurra Creek salinity upstream of Lough Calvert

Channel file Birreg.flo IQQM Birregurra Creek inflows upstream of Lough Calvert

Channel file Birreg.slt IQQM Birregurra Creek salinity upstream of Lough Calvert

Channel file Cc01_dmd IQQM System File that creates DA files for demand Cc01_evp IQQM System File that creates DA files for evaporation Cc01_flo IQQM System File that creates DA files for inflows Cc01_ppt IQQM System File that creates DA files for precipitation Cc01_slt IQQM System File that creates DA files for salinity Colac Inflows Excel Lake Colac inflows file Colac Rainfall Excel Lake Colac rainfall file Colac Salinity Excel Lake Colac salinity file Colac F Text Lake Colac inflows file Colac R Text Lake Colac rainfall file Colac S Text Lake Colac salinity file Colac.flo IQQM Lake Colac inflows file Colac.slt IQQM Lake Colac salinity file Corangamite Inflows V4 Excel Lake Corangamite inflows file Corangamite Rainfall v2 Excel Lake Corangamite rainfall file Corangamite Salinity v2 Excel Lake Corangamite salinity file CorangF4 Text Lake Corangamite inflows file CorangR Text Lake Corangamite rainfall file CorangS2 Text Lake Corangamite salinity file Corang.flo IQQM Lake Corangamite inflows file Corang.slt IQQM Lake Corangamite salinity file Dummy_DMD Excel Dummy demand file Dummy_FLO Excel Dummy inflow file Dummy_DMD Text Dummy demand file Dummy_FLO Text Dummy inflow file ‘dummy.dmd IQQM Dummy demand file ‘dummy.flo IQQM Dummy inflow file Evaporation Excel Evaporation file GDummey_SLT Excel Dummy groundwater salinity file GroundwaterDummy_FLO Excel Dummy groundwater inflow file Gdummey_SLT Text Dummy groundwater salinity file GDummy_FLO Text Dummy groundwater inflow file

‘gdummy.flo IQQM Dummy groundwater inflow file Gdummy.slt IQQM Dummy groundwater salinity file Gnarpurt Inflows V3 Excel Lake Gnarpurt inflow file Gnarpurt Salinity v2 Excel Lake Gnarpurt salinity file GnarpuF3 Text Lake Gnarpurt inflow file GnarpuS2 Text Lake Gnarpurt salinity file Gnarpurt.flo IQQM Lake Gnarpurt inflow file Gnarpurt.slt IQQM Lake Gnarpurt salinity file ‘gwcolac Excel Lake Colac groundwater inflow file ‘gwcolacS Excel Lake Colac groundwater salinity file ‘gwcolac Text Lake Colac groundwater inflow file ‘gwcolacS Text Lake Colac groundwater salinity file ‘gwcolac.flo IQQM Lake Colac groundwater inflow file Gwcolac.slt IQQM Lake Colac groundwater salinity file ‘gwcorang Excel Lake Corangamite groundwater inflow file ‘gwcorangS Excel Lake Corangamite groundwater salinity file ‘gwcorang Text Lake Corangamite groundwater inflow file ‘gwcorangS Text Lake Corangamite groundwater salinity file Gwcorang.flo IQQM Lake Corangamite groundwater inflow file Gwcorang.slt IQQM Lake Corangamite groundwater salinity file GWN020F2 Excel Groundwater inflow file for Node 020 file GWN020S2 Excel Groundwater salinity file for Node 020 file GWN020F2 Text Groundwater inflow file for Node 020 file GWN020S2 Text Groundwater salinity file for Node 020 file ‘gwn020f.flo IQQM Groundwater inflow file for Node 020 file ‘gwn020s.slt IQQM Groundwater salinity file for Node 020 file GWN074F2 Excel Groundwater inflow file for Node 074 file GWN074S2 Excel Groundwater salinity file for Node 074 file GWN074F2 Text Groundwater inflow file for Node 074 file GWN074S2 Text Groundwater salinity file for Node 074 file ‘gwn074f.flo IQQM Groundwater inflow file for Node 074 file ‘gwn074s.slt IQQM Groundwater salinity file for Node 074 file GWN075F2 Excel Groundwater inflow file for Node 075 file GWN075S2 Excel Groundwater salinity file for Node 075 file GWN075F2 Text Groundwater inflow file for Node 075 file GWN075S2 Text Groundwater salinity file for Node 075 file ‘gwn075f.flo IQQM Groundwater inflow file for Node 075 file ‘gwn075s.slt IQQM Groundwater salinity file for Node 075 file GWN076F3 Excel Groundwater inflow file for Node 076 file GWN076S3 Excel Groundwater salinity file for Node 076 file GWN076F3 Text Groundwater inflow file for Node 076 file GWN076S3 Text Groundwater salinity file for Node 076 file ‘gwn076f.flo IQQM Groundwater inflow file for Node 076 file ‘gwn076s.slt IQQM Groundwater salinity file for Node 076 file GWN077F2 Excel Groundwater inflow file for Node 077 file GWN077S2 Excel Groundwater salinity file for Node 077 file GWN077F2 Text Groundwater inflow file for Node 077 file GWN077S2 Text Groundwater salinity file for Node 077 file ‘gwn077f.flo IQQM Groundwater inflow file for Node 077 file ‘gwn077s.slt IQQM Groundwater salinity file for Node 077 file GWN078F2 Excel Groundwater inflow file for Node 078 file GWN078S2 Excel Groundwater salinity file for Node 078 file GWN078F2 Text Groundwater inflow file for Node 078 file GWN078S2 Text Groundwater salinity file for Node 078 file ‘gwn078f.flo IQQM Groundwater inflow file for Node 078 file ‘gwn078s.slt IQQM Groundwater salinity file for Node 078 file GWN079F2 Excel Groundwater inflow file for Node 079 file GWN079S2 Excel Groundwater salinity file for Node 079 file

GWN079F2 Text Groundwater inflow file for Node 079 file GWN079S2 Text Groundwater salinity file for Node 079 file ‘gwn079f.flo IQQM Groundwater inflow file for Node 079 file ‘gwn079s.slt IQQM Groundwater salinity file for Node 079 file IrrigDummy_DMD Excel Dummy file for irrigation demand file IRRIGDUM_DMD Text Dummy file for irrigation demand file Irrigdum.dmd IQQM Dummy file for irrigation demand file ‘lcdc.flo IQQM Lough Calvert Drainage Channel flow file Leigh Inflows v2 Excel Leigh River inflow file Leigh Salinity v2 Excel Leigh River salinity file Leigh F Text Leigh River inflow file Leigh S Text Leigh River salinity file Leigh.flo IQQM Leigh River inflow file Leigh.slt IQQM Leigh River salinity file Lower Inflows Excel Lower Lough inflow file Lower Salinity Excel Lower Lough salinity file Lower F Text Lower Lough inflow file Lower S Text Lower Lough salinity file Lower.flo IQQM Lower Lough inflow file Lower.slt IQQM Lower Lough salinity file Martin Inflows V3 Excel Lake Martin inflow file Martin Salinity v2 Excel Lake Martin salinity file MartinF3 Text Lake Martin inflow file MartinS2 Text Lake Martin salinity file Martin.flo IQQM Lake Martin inflow file Martin.slt IQQM Lake Martin salinity file Middle Inflows Excel Middle Lough inflow file Middle Salinity Excel Middle Lough salinity file MiddleF Text Middle Lough inflow file MiddleS Text Middle Lough salinity file Middle.flo IQQM Middle Lough inflow file Middle.slt IQQM Middle Lough salinity file N021_DMD2 Excel Node 021 demand file N021DMD2 Text Node 021 demand file ‘n021.dmd IQQM Node 021 demand file N031_DMD2 Excel Node 031 demand file N031DMD2 Text Node 031 demand file N115_DMD2 Excel Node 115 demand file N115DMD2 Text Node 115 demand file N117_DMD2 Excel Node 117 demand file N117DMD2 Text Node 117 demand file Sanctuary Inflows Excel Sanctuary inflow file Sanctuary Salinity Excel Sanctuary salinity file SanctuF Text Sanctuary inflow file SanctuS Text Sanctuary salinity file Sanct.flo IQQM Sanctuary inflow file Sanct.slt IQQM Sanctuary salinity file Spiers Inflows Excel Spiers Depression inflow file Spiers Salinity Excel Spiers Depression salinity file SpiersF Text Spiers Depression inflow file SpiersS Text Spiers Depression salinity file Spiers.flo IQQM Spiers Depression inflow file Spiers.slt IQQM Spiers Depression salinity file Upper Inflows Excel Upper Lough inflow file Upper Salinity Excel Upper Lough salinity file Upper F Text Upper Lough inflow file Upper S Text Upper Lough salinity file Upper.flo IQQM Upper Lough inflow file

Upper.slt IQQM Upper Lough salinity file US N014_DMD Excel Demand file from upstream of Node 014 USN014DM Text Demand file from upstream of Node 014 ‘usn014.dmd IQQM Demand file from upstream of Node 014 US N019_DMD Excel Demand file from upstream of Node 019 USN019DM Text Demand file from upstream of Node 019 ‘usn019.dmd IQQM Demand file from upstream of Node 019 USN118DM Text Demand file from upstream of Node 118 ‘usn118.dmd IQQM Demand file from upstream of Node 118 Warrambine Inflows v2 Excel Warrambine River inflow file Warrambine Salinity v2 Excel Warrambine River salinity file WarramF Text Warrambine River inflow file WarramS Text Warrambine River salinity file Warram.flo IQQM Warrambine River inflow file Warram.slt IQQM Warrambine River salinity file WB-EVAP Text Wurdee Boluc evaporation file Wb.evp IQQM Wurdee Boluc evaporation file Woady Inflows Excel Woady Yaloak River inflow file Woady Salinity Excel Woady Yaloak River salinity file Woady F Text Woady Yaloak River inflow file Woady S Text Woady Yaloak River salinity file


Appendix C

Storage Information

GHD www.ghd.com.auTel. (03) 9278 2200 Fax. (03) 9600 1300380 Lonsdale Street Melbourne Vic 3000

Storage Information - Lake Corangamite

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Sheets 1 to 5 of Plan No 77367, Type: No outlet exists Type: Assumed unregulated spilling occurs above EL 119.85

and from Capacity Curve Plan No 77868Plans produced by the State Rivers and Water Supply Commission

Stage(mAHD)

Volume(ML)

Area(ha) Comments Stage

(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

112.11 0 0 112.11 0 0 112.11 0 0112.60 100,000 11,915 112.60 100,000 0 112.60 100,000 0112.88 150,000 17,026 112.88 150,000 0 112.88 150,000 0113.16 200,000 17,762 113.16 200,000 0 113.16 200,000 0113.44 250,000 18,497 113.44 250,000 0 113.44 250,000 0113.69 300,000 19,232 113.69 300,000 0 113.69 300,000 0113.93 350,000 19,968 113.93 350,000 0 113.93 350,000 0114.18 400,000 20,703 114.18 400,000 0 114.18 400,000 0114.41 450,000 21,438 114.41 450,000 0 114.41 450,000 0114.64 500,000 22,174 114.64 500,000 0 114.64 500,000 0114.86 550,000 22,500 114.86 550,000 0 114.86 550,000 0115.08 600,000 22,773 115.08 600,000 0 115.08 600,000 0115.30 650,000 23,047 115.30 650,000 0 115.30 650,000 0115.51 700,000 23,320 115.51 700,000 0 115.51 700,000 0115.72 750,000 23,594 115.72 750,000 0 115.72 750,000 0115.94 800,000 23,867 115.94 800,000 0 115.94 800,000 0116.15 850,000 24,140 116.15 850,000 0 116.15 850,000 0116.34 900,000 24,414 116.34 900,000 0 116.34 900,000 0116.53 950,000 24,687 116.53 950,000 0 116.53 950,000 0116.74 1,000,098 24,961 116.74 1,000,098 0 116.74 1,000,098 0116.93 1,050,000 25,234 116.93 1,050,000 0 116.93 1,050,000 0117.13 1,100,000 25,507 117.13 1,100,000 0 117.13 1,100,000 0117.29 1,150,000 25,781 117.29 1,150,000 0 117.29 1,150,000 0117.44 1,200,000 26,054 117.44 1,200,000 0 117.44 1,200,000 0117.60 1,250,000 26,327 117.60 1,250,000 0 117.60 1,250,000 0117.75 1,300,000 26,601 117.75 1,300,000 0 117.75 1,300,000 0117.91 1,350,000 26,874 117.91 1,350,000 0 117.91 1,350,000 0118.06 1,400,000 27,147 118.06 1,400,000 0 118.06 1,400,000 0119.85 1,860,000 30,000 119.85 1,860,000 0 119.85 1,860,000 999,999

Recorded Levels Model Starting Conditions Other CommentsSource: Monthly Theiss Data GS

Salinity 26/1/98 - 20/2/03 1974 1986Levels 26/1/98 - 20/2/03 641,160 577,000

Weekly Data Sheets 1,860,000 1,860,000Salinity 27/11/86 - 1/12/94, 5/7/97 - 1/2/03 1,860,000 1,860,000Levels 27/11/86 - 1/12/94, 5/7/97 - 1/2/03 36,300 40,000Salinity (mg/L)

Comments

Start Vol (ML)Dead Storage Vol (ML)Full Supply Vol (ML)

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Storage Information - Cundare Pool and Lake Martin

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Plan No 76589, Type: Pipe Outlet - 5 No x 900 Dia Type: Nil - included in outlet

and from Capacity Curve Plan No 58684 EL 116.57Plans produced by the State Rivers and Water Supply Commission

Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

114.90 0 0 114.90 0 0116.26 15,412 2,469 116.26 15,412 0116.57 22,163 2,958 116.57 22,163 1116.82 27,062 3,318 116.82 27,062 100116.97 30,825 3,586 116.97 30,825 0117.50 46,237 4,183 117.50 46,237 475117.57 60,463 4,521 117.57 60,463 750118.18 61,650 3,348 118.18 61,650 850118.29 70,687 5,336 118.29 70,687 1,500118.37 77,062 5,855 118.37 77,062 2,800118.41 80,145 6,118 118.41 80,145 2,800

Recorded Levels Model Starting Conditions Other CommentsSource: Daily Theiss Data GS

Salinity 1974 1986 Includes Lake MartinLevels 20,000 32,500

Weekly Data Sheets 0 0Salinity 27/11/86 - 1/12/94, 5/7/97 - 1/2/03 80,145 80,145Levels 27/11/86 - 1/12/94, 5/7/97 - 1/2/03 4,100 4,100

Comments

Start Vol (ML)Dead Storage Vol (ML)

Salinity (mg/L)Full Supply Vol (ML)

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Storage Information - Black Bridge Pool

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Plan No 76589 Type: Type:

Plan produced by the State Rivers and Water Supply Commission

Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

114.90 0 0 114.90 0 0 114.90 0 0115.81 50 5 115.81 50 0 115.81 50 0116.80 360 22 116.80 360 1 116.80 360 0117.10 400 50 117.10 400 25 117.10 400 0117.40 460 71 117.40 460 50 117.40 460 0117.90 600 112 117.90 600 175 117.90 600 0118.21 650 150 118.21 650 450 118.21 650 99,999


Salinity 1974 1986Levels 120 120

Weekly Data Sheets 359 359Salinity 27/11/86 - 1/12/94, 5/7/97 - 1/2/03 600 600Levels 27/11/86 - 1/12/94, 5/7/97 - 1/2/03 5,500 5,500

Comments

Discharge to Woady Yaloak Channel reduced to 450 ML in calibration model, to match historical releases


Salinity (mg/L)Full Supply Vol (ML)

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Storage Information - Spiers Depression

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Sheets 12 to 8 of 2 m Contour Plan 108723 Type: Spiers Regulator Type: No spillway included.

Plans produced by the State Rivers and EL 112.35 Assumed uncontrolled spilling above EL 113.10Water Supply Commission

Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

112.25 0 0 112.25 0 0 112.25 0 0112.35 5 25 112.35 5 170 112.35 5 0113.00 300 170 113.00 300 170 113.00 300 0113.10 350 230 113.10 350 170 113.10 350 999,999113.70 600 580 113.70 600 170 113.70 600 999,999114.00 800 750 114.00 800 170 114.00 800 999,999116.00 2,500 900 116.00 2,500 170 116.00 2500 999,999

Recorded Levels Model Starting Conditions Other CommentsSource: No recorded level or salinity data exists

1974 198620 205 5

350 35050,000 50,000Salinity (mg/L)


Comments

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Storage Information - Lower Lough

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Adams 1990 and extended using Type: Warrowie Regulator Type:

Sheets 12 to 8 of 2 m Contour Plan 108723Plans produced by the State Rivers and Water Supply Commission

Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

111.20 0 0 111.20 0 0 111.20 0 0111.30 5 25 111.30 5 170 111.30 5 0112.00 1,000 220 112.00 1,000 170 112.00 1,000 0113.00 6,000 600 113.00 6,000 170 113.00 6,000 0114.00 12,500 1,000 114.00 12,500 170 114.00 12,500 0115.00 23,000 1,250 115.00 23,000 170 115.00 23,000 51,410115.90 36,000 1,450 115.90 36,000 170 115.90 36,000 134,640116.00 40,000 1,600 116.00 40,000 170 116.00 40,000 145,410


1974 198620 205 5

12,500 12,500100,000 100,000Salinity (mg/L)


Area given as 0 in print out

Comments

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Storage Information - Middle Lough

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Adams 1990 and extended using Type: Type: Causeway


Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

111.00 0 0 111.00 0 0 111.00 0 0111.20 1,500 500 111.20 1,500 0 111.20 1,500 0112.00 3,000 670 112.00 3,000 0 112.00 3,000 0113.00 10,000 1,000 113.00 10,000 0 113.00 10,000 0114.00 23,000 1,250 114.00 23,000 0 114.00 23,000 0115.40 42,000 1,700 115.40 42,000 170 115.40 42,000 51,100116.00 55,000 2,000 116.00 55,000 170 116.00 55,000 87,250


1974 1986500 500

23,000 23,00023,000 23,00016,000 16,000Salinity (mg/L)

Comments

Dead Storage Vol (ML)Full Supply Vol (ML)

Start Vol (ML)

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Storage Information - Upper Lough

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Adams 1990 and extended using Type: Type:


Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

111.00 0 0 111.00 0 0 111.00 0 0111.20 1,000 200 111.20 1,000 0 111.20 1,000 0112.00 4,000 400 112.00 4,000 0 112.00 4,000 0113.00 10,150 830 113.00 10,150 0 113.00 10,150 0114.00 19,800 1,100 114.00 19,800 0 114.00 19,800 0115.00 32,800 1,400 115.00 32,800 0 115.00 32,800 0116.00 48,800 1,700 116.00 48,800 0 116.00 48,800 999,999


1974 1986500 500

48,800 48,80048,800 48,80035,000 35,000Salinity (mg/L)

Comments


Start Vol (ML)

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Storage Information - Sanctuary

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Adams 1990 and extended using Type: Type:


Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

111.00 0 0 111.00 0 0 111.00 0 0112.00 1,000 250 112.00 1,000 0 112.00 1,000 0113.00 1,400 380 113.00 1,400 0 113.00 1,400 0114.00 5,800 500 114.00 5,800 0 114.00 5,800 0115.00 11,800 700 115.00 11,800 0 115.00 11,800 0116.00 19,800 900 116.00 19,800 0 116.00 19,800 0


1974 1986300 300

5,800 5,8005,800 5,8003,500 3,500Salinity (mg/L)

Comments


Start Vol (ML)

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Storage Information - Lake Murdeduke

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Adams (1990) Type: Not included Type: Not included

Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

0 0625 1,250

1,250 2,5001,875 3,7502,500 5,0003,125 6,2503,750 7,5004,375 8,7505,000 10,000


Salinity 1974 1986Levels 1,000 1,000

Weekly Data Sheets 5,000 5,000Salinity 4/12/86 - 1/12/94 5,000 5,000Levels 4/12/86 - 1/12/94 5,000 5,000

Comments

Full Supply Vol (ML)Salinity (mg/L)


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Storage Information - Lake Gnarpurt

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: Derived from Sheet 1 of Plan No 77367, Type: Type:

Plans produced by the State Rivers and Water Supply Commission

Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

113.00 0 0 113.00 0 0 113.00 0 0113.50 13,750 1,850 113.50 13,750 0 113.50 13,750 0114.10 27,500 2,070 114.10 27,500 0 114.10 27,500 0114.70 41,250 2,240 114.70 41,250 0 114.70 41,250 0115.30 55,000 2,410 115.30 55,000 0 115.30 55,000 0115.90 68,000 2,590 115.90 68,000 0 115.90 68,000 0116.00 70,000 2,800 116.00 70,000 0 116.00 70,000 180118.18 110,000 3,000 118.18 110,000 0 118.18 110,000 180118.21 150,000 3,500 118.21 150,000 0 118.21 150,000 180

Recorded Levels Model Starting Conditions Other CommentsSource: Monthly Theiss Data GS

Salinity 26/1/98 - 20/2/03 1974 1986Levels 26/1/98 - 20/2/03 74,680 74,680

Weekly Data Sheets 70,000 70,000Salinity 27/11/86 - 1/12/94, 5/7/97 - 25/1/03 110,000 110,000Levels 27/11/86 - 1/12/94, 5/7/97 - 25/1/03 10,400 10,400

Comments



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Storage Information - Lake Colac

Stage / Volume / Area Relationship Outlet Details Spillway DetailsSource: SR & WSC, July 1979 - Figure 2A Type: 2 No x 90mm DIA PIPE OUTLET X 30 m long Type: 30m wide spillway

Derived from Plan No 108457 INV EL 115.25 mAHD EL 117.40Plan produced by the State Rivers and Water Supply Commission

Stage(mAHD)

Volume(ML)


(mAHD)Volume

(ML)Discharge

(ML/d)Stage

(mAHD)Volume

(ML)Discharge

(ML/d) Comments

114.80 5,000 1,800 114.80 5,000 0 114.80 5,000 0115.00 10,000 2,200 115.20 14,999 0 115.00 10,000 0115.20 15,000 2,250 Outlet EL 115.25 115.20 15,000 170 115.20 15,000 0115.40 20,000 2,500 115.40 20,000 170 115.40 20,000 0116.00 35,000 2,750 116.00 35,000 170 116.00 35,000 0117.00 62,000 2,900 117.00 62,000 170 117.00 62,000 0117.40 76,000 3,000 Spillway EL 117.40 117.40 76,000 170 117.40 76,000 0 Spilling commences at 117.40117.50 78,000 3,050 117.50 78,000 170 117.50 78,000 350117.60 80,000 3,100 117.60 80,000 170 117.60 80,000 600

Recorded Levels & alinity Data Model Starting Conditions Other CommentsSource: Daily Theiss Data GS

Salinity 27/11/86 - 1/12/94, 5/7/97 - 25/1/03 1974 1986Levels 27/11/86 - 1/12/94, 5/7/97 - 25/1/03 64,000 40,000

Weekly Data Sheets 14,999 14,999Salinity 17/5/95 - 13/1/2003 76,000 76,000Levels 17/5/95 - 13/1/2003 2,100 2,500

Note: mg/L = 0.7 EC


Assumed max. discharge is equal to capacity of Lough Calvert Drainage Channel


Discharge through outlet reduced to 150 ML in calibration model, to match historical releases from Colac

Comments

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Appendix D

Groundwater Summary


Groundwater Assessment

Bore information was sourced from an Access database supplied by the CCMA, that included bore records from the State Groundwater Database and monitoring data from State and CCMA sources.

Monitoring bores are not distributed across the region and significant areas do not have groundwater monitoring coverage from which data on groundwater – surface water interactions can be adequately assessed. In many areas data concerning groundwater parameters, levels and salinity are assumed for long stream sections or lakes based on nearest available data points or typical values noted elsewhere in the region. Aquifer parameters used have been obtained from bore pump tests conducted in the region and an estimate of the typical range of parameters relevant to each geologic formation. Unless specific data exists to the contrary it is generally assumed that similar groundwater levels occur on both sides of a stream, with aquifer characteristics modified by geology.

Although it is likely that regional aquifer systems contribute to inflows to the streams (and storages) in the area, only information provided by shallow bores was considered. In the absence of bore construction details for all bores, a maximum bore depth of 30 metres was selected. Upon closer inspection, where there was conflicting data, for example where closely adjacent bores showed markedly different Standing Water Levels (SWLs) data was initially chosen to provide a “worst case” ie. potential largest groundwater inflows to streams and hence highest potential salt loads. The hydraulic parameters, section length of stream receiving groundwaters, and the radius of the zone of influence were then modified during the calibration process.

Although seasonal fluctuations were considered with respect to groundwater direction and likely change in head, no attempt has been made to model seasonal fluctuations in potential groundwater inflow to streams. In many areas fluctuations are less than 1 metre, and in comparison with the accuracy of other data used in the assessment, seasonal fluctuations were considered not to be significant in a preliminary assessment.

Potential groundwater inflow calculations are based on simple Darcy flow relationship. A key relationship is flow gradient and the distance from streams or lakes to which the inflow gradient applies. There is little monitoring data in the region from which typical groundwater inflow sections to lakes / streams can be assessed or the variability of gradients in differing topographic or geologic areas.

In particular the Birregurra Creek, the Barwon River upstream of Winchelsea, and the Warrambine Creek have few adjacent monitoring bores. No sensitivity analysis has been carried out to determine the impact of varying inflow gradients, with a conservative (over-estimate) of gradients applied to inflow calculations. However, as noted above, some revision of groundwater inflow parameters were made based on the outcomes of initial surface water modelling to better match apparent surface water salt loads.

Further potential errors in groundwater inflow calculation occur from significant uncertainty in stream and lake water levels, particularly for the smaller lakes and streams. Estimates of groundwater inflow have assumed water levels based on an assessment of topography, bed level and anecdotal evidence of seasonal flows and water levels. No attempt has been made to evaluate seasonal fluctuation in stream water levels.


The equation used to determine groundwater flows was:

ΣQn= FG * Σ(Dn Kn (Hn2 – hn2)/2Ln)

Where: Q = groundwater discharge in m3/day

K = Horizontal hydraulic conductivity in m/day

H = Height of the water table at the groundwater divide in mAHD

‘h = Height of the surface water in mAHD

L = Distance between the groundwater divide and the surface water in m

D = Length of the reach along which groundwater is discharging in m

‘n = the nth soil type

FG = local calibration parameter

As these parameters vary dependent on topography and geology, this equation is modified for each distinct area and discharge summed to find the overall discharge into the stream reach or storage.

The initial parameters for each reach of the system are given in Table D-1. These were reviewed during the calibration process, with correction factors applied as discussed in the body of this report.

Table D-1 Groundwater Parameters

Reach Soil Types K H h D L TDS


Lake Colac Stony Rises 5 120

Varies with Storage Height 10089 4000 2100

Lough Calvert Channel

Quaternary Sands 1 114 110 24000 1000 1400

Basalt Plains 1.5 110 103 1800 1500 2800 Birregurra Creek Tertiary

Sands 3 110 103 4200 1500 2800

Barwon before Kildean’s Lane

Quaternary Sands 1 85 82.5 23872 2000 5950

Quaternary Sands 1 85 82.5 6627 2000 6300

Barwon Before Winchelsea Tertiary

Sands 3 85 82.5 6627 2000 8400


Reach Soil Types K H h D L TDS

Quaternary Sands 0.1 77 75 18600 3000 5250 Barwon before

Inverleigh Basalt Plains 1 77 75 18600 3000 32000

Quaternary Sands 1 72 67 10372 2000 10000 Barwon

Downstream of Inverleigh Tertiary

Sands 3 72 67 1152 1000 21000

Quaternary Sands 1 62 57 2000 2000 10000 Barwon

Downstream of Warrambine Basalt Plains 1.5 62 57 2000 2000 10500

Stony Rises 8 118

Varies with changes in Lake height

51975 2000 4200

Basalt Plains 2 118 8025 2000 7000

Lake Corangamite

Tertiary Sands 5 118 15000 2000 7000


Basalt Plains 2 110 10000 1500 7000 Cundare Pool


Varies with storage height

10000 1500 7000

Warrambine River

Quaternary Sands 1 105 100 12000 2500 10000

The following section summarise uncertainties and assumptions used for each of the individual sections studied.

Lake Colac

There was evidence that the groundwater flow moved from the west to the east regionally, with the Lake losing water to the aquifer on the east side. This was based on approximately about groundwater monitoring bores.

Lough Calvert Drainage Channel

There were only four groundwater monitoring bores adjacent to the Lough Calvert Channel. These bores, however showed that the water table was well above the historical channel depth as supplied by the current scheme operations contractor (Earthtech). There was evidence of southerly flow, and it was assumed that although the entire length of the channel with a groundwater reduced level of less than 114


meters would be effected, the inflow would occur from the east, in line with the regional groundwater flow.

Birregurra Creek

In general, surface water data and anecdotal evidence suggest that little groundwater inflow is expected, and there is a possibility of surface water loss to the water table given that groundwater levels appear to be below stream bed for a significant length of the stream. However, the groundwater levels in several bores indicated that there was potential for seasonal flow to the stream. This suggests that the stream is perched in some way above the regional groundwater flow system. This is unlikely drainage behaviour for the entire length of the stream and as a conservative approach the file remains an inflow file.

Barwon River System

It should be noted that there was no information available regarding the elevation of the riverbed. Although level is provided in some data sources these are not connected to any datum. Therefore in assessing potential groundwater inflows surface water elevation was determined using topographical information from the 10 m topographical maps, and by analysing bore information where bores were located close to the river.

Barwon River Upstream of Kildean’s Lane and Winchelsea.

Data used was based on a very small number of groundwater monitoring bores located close to the Barwon near to Kildeans’ Lane. These bores were located in close proximity to each other and to the Barwon River.

Barwon River Upstream of Inverleigh

There are a number of groundwater monitoring bores on both sides of the Barwon that provide information regarding groundwater flow. There appears to be a general west to easterly flow from the western side of Lake Murdeduke towards the Barwon River. The river appears to have a gradient of about ten metres with the river being higher in the south and lower in the north of the section. Bores adjacent to the river were used to determine the potential average height of water in the river. Groundwater salinity ranges from 12000 to 110000 EC.

It should be noted that Roderick (1988) concluded that the average range of inflows is in the range of 0.1 to 1 ML/day, with inflows of less than 0.2 ML/day being rare. Roderick notes an average groundwater salinity of 30000 EC per day. The dominant geology is noted as being 50% Basalt Plains and 50% Quaternary sands. The adopted K values are 1.0 and 0.1 m/day respectively and the maximum height of the water table is given as 77m. The lateral area of influence away from the river for groundwater inflow gradient calculation has been chosen as 3 km based on groundwater levels.

Barwon from Inverleigh to Warrambine River

There were few groundwater monitoring bores available on this reach. It was assumed that the groundwater behaviour exhibited up to the Inverleigh Gauge station would continue until the confluence of the Warrambine and the Barwon.

Barwon Downstream of Warrambine River

Once again the number of relevant monitoring bores was limited to only a few. There appeared to be some limited groundwater intrusion to the Barwon from both sides of the river.


Lake Corangamite

There was evidence of inflow to most of Lake Corangamite. It appears that there is a north-south groundwater divide between Lake Corangamite and Lakes Beeac and Colac. Overall, groundwater intrusion into the lake is likely to be significant. Many groundwater monitoring bores were sourced for this analysis. Groundwater salinity records on the eastern margin of the lake around Wool Wool suggest that seasonally, where lake levels are higher than watertable levels, flow from the lake to the shallow aquifer may occur. This is supported by anecdotal evidence.

A difference in water levels in Corangamite and Cundare Pool appear to be reflected in groundwater levels adjacent to each lake. No assessment of potential inflows to the Pool were completed as no storage levels are available. Elevated groundwater salinity near the Pool could have a significant impact on surface water quality if groundwater discharge occurs.

Warrambine Creek

There were no relevant bores in the area of the southern Warrambine. Therefore the inflow file was based on topography and general hydrogeological principles. There was a high level of uncertainty here, with modification to the modelled inflows based on the calibration of the surface water modelling.


GHD Pty Ltd ABN 39 008 488 373

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© GHD Pty Ltd 2003

This document is and shall remain the property of GHD Pty Ltd. The document may only be used for the purposes for which it was commissioned and in accordance with the Terms of Engagement for the commission. Unauthorised use of this document in any form whatsoever is prohibited.

Document Status

Reviewer Approved for Issue Rev No. Author

Name Signature Name Signature Date

0 S Roach D Mitchell / P Priebbenow

***** PDP

J Franklin ***** JMF 20/8/03

* denotes signature on original document

corangamite catchment management authority

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