Assessment of Accuracy of Baseflow Estimates Targeted Ground-Truthing of Existing Data

DELWP Assessment of Accuracy of Baseflow Estimates Targeted ground-truthing of existing data

May 2016

Executive summary

Background

The Department of Environment, Land, Water and Planning (DELWP) previously undertook two projects to fill information gaps on priority Groundwater Dependent Ecosystems (GDE) – baseflow dependent rivers, and wetlands. These projects, completed by GHD (GHD 2013a; GHD 2013b), developed a methodology to:

 establish where groundwater interaction occurs with rivers and wetlands

 quantify the groundwater contribution to the waterway where interaction occurs  identify associated high value environmental assets, and

 assess the risk to these environmental assets from groundwater extraction.

A discussion paper was prepared by GHD in 2012 to appraise methods for quantifying regional groundwater discharge to streams (as “baseflow”) throughout Victoria. The adopted baseflow estimation method involved digital baseflow filtering “trained” to environmental tracer data – primarily electrical conductivity.

A pilot project was undertaken by GHD in 2012/13 for characterising the baseflow contributions for five Victorian rivers (GHD, 2013a), including the lower Mitchell and lower Thomson- Macalister Rivers. This project was expanded in 2013 (GHD, 2013b) to a further eight Victorian rivers including the Latrobe River catchment, using the same method. As for the pilot method, the results were used to assess the risk of groundwater extraction to the environmental values that those rivers support.

Project objectives

The primary objective of this project is to implement the recommendations from the scientific review of the method developed by GHD (GHD, 2013a; GHD, 2013b) to improve the accuracy and reliability of the baseflow estimates to three high value Gippsland river systems:

 Latrobe River (Latrobe River to Kilmany South)

 Thomson-Macalister River system (Thomson River from Cowwarr Weir to Bundalaguah; Macalister River from Lake Glenmaggie to the confluence with the Thomson River), and

 Mitchell River (Glenaladale to Rosehill). The objective of this project is to improve understanding of the degree and nature of interaction between rivers and groundwater in the Gippsland region, and to help understand potential impacts of coal mining, coal seam gas developments and other water uses on water-dependent environmental assets. The outputs of the work will improve the accuracy of, and confidence in, estimates of the dependency of flows on groundwater and improve the technical basis on the likelihood of direct, indirect and cumulative impacts of water use on baseflows.

One of the key outcomes from this study is to provide a tiered framework for the application of the baseflow estimation method(s) most suitable for different types of reaches, such as losing, gaining and regulated reaches.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | i The project has been completed in two stages:

 Stage 1: Review groundwater contributions to rivers  Stage 2: Targeted ground-truthing of existing data (data verification)

This report documents the Stage 2 assessment.

Scope of Work

Following on from the work completed in Stage 1 of this study (GHD, 2015), the scope of work for Stage 2 of the study includes:

 Develop a field work plan to undertake monitoring at targeted ground-truthing sites;

 Undertake proposed field work at targeted locations and monitoring periods, based on the field work plan;

 Refine the baseflow analysis and interstation analysis based on the ground-truthing data; and

 Undertake high level analysis to assess potential effects that coal seam gas extraction may have on groundwater – surface water interactions.

Previous Work

Findings from Stage 1 of the study (GHD, 2015) highlighted a number of data gaps which increase the uncertainty of baseflow estimates. The key data gaps include:  Surface water flow and EC – gaps in concurrent flow and EC gauging data between upstream and downstream sites which reduce the ability to implement interstation analyses;  Groundwater EC – limited groundwater monitoring bores in upland catchments to define groundwater EC end members;

 Surface Water Management – gaps in the surface water management data, in particular river diversions and returns; and

 Independent baseflow studies – limited relevant independent baseflow studies to assess the effects of the recommended changes and additions to the baseflow assessment method on the reliability of the baseflow estimates.

The table below summarises the data available for the interstation reaches in the Latrobe, Thomson-Macalister and Mitchell River catchments. The findings indicate that there are no concurrent surface water flow and EC recordings for the Latrobe River upstream of Thoms Bridge, and the Latrobe River between Thoms Bridge and Scarnes Bridge. Additionally, there is limited data available for the Thomson River between Cowwarr Weir and Heyfield, and the Macalister River between Glenmaggie and Riverslea.

Furthermore, the Mitchell River between Glenaladale and Rosehill is the only assessed reach with an independent data set suitable for assessing the reliability of the EC mass balance method of baseflow estimation: those of Hofmann (2011). Therefore, it was recommended that monitoring investigations conducted as part of Stage 2 are focused on providing additional data for the Latrobe or Thomson-Macalister River catchments.

ii | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Count of Period of con- Count of Interstation Gauge concurrent Interstation Section current flow and GW EC Pairs flow and SW SW EC readings Boreholes EC readings Latrobe River upstream of 226216, 226021, NA 0 174 Thoms Bridge 226408, 226005 Latrobe River between 226005, 226007, NA 0 13 Thoms Bridge and Scarnes 226415, 226033 Bridge Latrobe River between 226033, 226228 7/01/1997 - 194 53 Scarnes Bridge and 5/05/2013 Rosedale Latrobe River between 226228, 226227 18/05/1977 - 222 93 Rosedale and Kilmany 3/12/2014 South Thomson River between 225231, 225200, 17/10/2007 3 12 Cowwarr Weir and Heyfield 225236 8/04/2010 Thomson River between 225200, 225236, 10/08/2005 73 10 Heyfield and Wandocka 225212 5/09/2012 Lower Thomson-Macalister 225212, 225232, 13/07/2005 93 43 River from Wandocka to 225247 22/05/2014 Bundalaguah including Macalister River Macalister River between 225204, 225247 5/03/2007 9 69 Glenmaggie and Riverslea 4/04/2012 Mitchell River between 224203, 224217 11/01/1977 82 54 Glenaladale and Rosehill 15/12/2014

Field Work

A targeted field work plan to undertake flow and EC accretion profiling was developed in consultation with DELWP, WG-CMA and SRW, based on the key data gaps identified in Stage 1 (GHD, 2015) and tailored to the following key reaches of interest:

 Thomson River from Cowwarr to Wandocka, including Rainbow Creek (9 sampling locations);

 Moe Drain / Latrobe River upstream of Lake Narracan, including Tanjil River and Narracan Creek (12 sampling locations); and

 Macalister River between Glenmaggie and Maffra Weir (5 sampling locations).

Spot sampling was undertaken for three sampling rounds over the study period to collect data for different seasons and regulated influences (irrigation releases):

 Sampling Round 1: Spring 2015 (09/09/2015 – 28/09/2015). Capture flows at the start of the irrigation season.  Sampling Round 2: Summer 2016 (12/01/2016 – 05/02/2016): Capture summer low flows.

 Sampling Round 3: Autumn 2016 (12/04/2016 – 17/05/2016): Capture flows at the end of the irrigation season.

During the sampling events important changes were noted by field staff. Each sampling event was conducted to avoid peak streamflow after high rainfall events and after large reservoir releases, when the flow rate was below the median flow for the month of year. Sampling was also avoided when the rainfall forecast for the work week was greater than 5 mm. At these times, the difference in streamflow between sites is relatively stable; i.e. there is not a pulse of

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | iii runoff or reservoir release water travelling down the river, which would serve to complicate and undermine the field data analyses.

Revised Baseflow Estimates

Downstream flow and EC ‘accretion profiles’ were prepared based on the field observations to provide an indication of the changes in streamflow conditions along each river. These flow and EC accretion profiles can be used to infer baseflow contributions to the stream, with baseflow gains likely when EC is increasing between upstream and downstream sampling sites (i.e. within an ‘interstation reach’). To further quantify the magnitude of baseflow gains, reach-scale mass balances were constructed using the field data, in the same manner as was applied by GHD (2015) using historical gauge data.

Results for all sampled reaches indicate that baseflow-conditions (i.e. gain from or loss to groundwater) are variable along the reach length and between seasons.

Thomson River Across seasons, there are consistent baseflow gains exhibited along Rainbow Creek, which is more deeply incised into the landscape than the main channel of the Thomson River. Rainbow Creek likely forms a natural drain towards which groundwater from beneath the more elevated Thomson River will flow. Relatively consistent baseflow gains are exhibited in the reach downstream of Cowwarr Weir, particularly during high flows into and out of the weir. This is most likely due to the lower river bed and stage immediately downstream of the weir, effectively forming a drain towards which groundwater from beneath the weir is driven.

Baseflow conditions along the Thomson River between Stoney Creek and Wandocka vary between seasons, ranging from predominantly baseflow gaining conditions during spring to neutral conditions during summer and autumn. It is noted that baseflow conditions were uncertain along several reaches, where gains in EC could potentially be attributed to evaporation losses, rather than baseflow gains.

Macalister River The only reaches exhibiting seasonally-consistent baseflow conditions are between US Newry Drain and US Maffra Weir, and DS Maffra Weir to Riverslea, where gains were observed across all sampling events. The seasonal neutral to losing behaviour concluded for the upstream reach (between DS Glenmaggie and US Newry Drain) makes sense conceptually due to the relatively elevated river bed, when compared to downstream reaches. The elevated river bed - in conjunction with high river flows (releases from Glenmaggie Weir in Summer (January 2016)) - create hydraulically losing conditions in this reach. Losing behaviour in basin margin reaches was also noted in earlier studies by GHD (2013a).

The observations are in broad agreement with the earlier work of GHD (2015). The broad picture of neutral to losing conditions downstream of Glenmaggie Weir, and generally gaining conditions downstream of Newry Drain (aside from around Maffra Weir) is consistent with the earlier work, noting that there are temporal differences.

Latrobe River Moderately gaining baseflow conditions are consistently experienced across seasons for the upper reaches of the Latrobe River, Tanjil River and Narracan Creek; however, baseflow gains are generally reduced in summer. The data suggests relatively variable seasonal baseflow condtions along the Moe Drain, with predominantly gaining conditions exhibited during spring and relatively neutral conditions during summer and autumn.

iv | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Effect of Coal Seam Gas Extraction on Baseflow

A high level analysis was completed to assess potential effects that coal seam gas extraction may have on groundwater – surface water interactions, drawing on findings from relevant literature. It is noted that there is potential for onshore coal seam gas production to have significant impacts on baseflow in the Gippsland region, as reported in DELWP (2015). However, the magnitude of the impact depends on the location of the CSG development, the stratigraphy of the gas bearing formations and the scale of the CSG development.

Review of historical groundwater hydrographs in the region indicates that the historical impacts of groundwater depressurisation for coal mining in the region have had limited impacts on the shallow aquifer systems.

Conclusions and Recommendations

This study obtained targeted field data aimed at ground-truthing the baseflow estimates derived in Stage 1 of this study (GHD, 2015) for river reaches of interest to stakeholders. While highly localised studies and field data do not broadly inform the regional-scale conceptualisation and analysis of groundwater-surface water interactions, they do provide a valuable basis for constraining the estimates, thereby improving the confidence of more broad-scale approaches.

A key outcome of this study was the development of field sampling condition criteria to select conditions that will give the most accurate and representative results. It is recommended that future field investigation studies adopt similar sampling criteria. Another recommendation from this study is to obtain field results for major ions - in additional to EC - for sites downstream of known agricultural or industrial discharges. This will confirm whether EC is representative of Chloride, or if it represents some other solute such as nitrogen. It is also recommended that any offtakes and outfalls within the monitored reaches are also recorded as part of the field sampling program.

This study refined the method for estimating interstation baseflow for detailed sub-reach mass balances, compared to the broader mass balances implemented in Stage 1. The recommended revised method for further baseflow studies is to estimate the EC of diverted water based on a river chainage-based interpolation to the diversion location, from the two gauge locations at the upstream and downstream ends of each assessed reach, and adopting the revised reach scale mass balance equation. The refinement to the equation should result in the highest possible degree of consistency between detailed sub-reach scale mass balances and broader scale mass balances. For specific river reaches of interest to water managers and other stakeholders, there would be value in implementing an ongoing annual program of spatially detailed field sampling and analyses, for which this study forms a guide. Based on sampling results, a database of baseflow gains and flow losses along these reaches could be developed. This ‘baseflow conditions’ database would form a sound basis for more broadly characterising and better understanding priority river reaches in terms of seasonal baseflow conditions; in addition to how those conditions may change under variable climatic conditions and in response to land, water and resource developments. These broad characteristics could then be applied in:

 More robustly assessing the significance and value of groundwater inputs to environmental flows under a range of conditions

 Assessing threats to groundwater-dependent components of environmental flows, and

 Evaluating ongoing water management needs and options, licensing decisions, and approvals for significant land, water and resource developments.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | v Limitations

This report: has been prepared by GHD for DELWP and may only be used and relied on by DELWP for the purpose agreed between GHD and the DELWP as set out in Section 1.2 of this report.

GHD otherwise disclaims responsibility to any person other than DELWP arising in connection with this report. GHD also excludes implied warranties and conditions, to the extent legally permissible.

The services undertaken by GHD in connection with preparing this report were limited to those specifically detailed in the report and are subject to the scope limitations set out in the report.

The opinions, conclusions and any recommendations in this report are based on conditions encountered and information reviewed at the date of preparation of the report. GHD has no responsibility or obligation to update this report to account for events or changes occurring subsequent to the date that the report was prepared.

The opinions, conclusions and any recommendations in this report are based on assumptions made by GHD described throughout this report. GHD disclaims liability arising from any of the assumptions being incorrect.

The opinions, conclusions and any recommendations in this report are based on information obtained from, and testing undertaken at or in connection with, specific sample points. Site conditions at other parts of the site may be different from the site conditions found at the specific sample points.

Investigations undertaken in respect of this report are constrained by the particular site conditions, such as the location of buildings, services and vegetation. As a result, not all relevant site features and conditions may have been identified in this report.

Site conditions may change after the date of this Report. GHD does not accept responsibility arising from, or in connection with, any change to the site conditions. GHD is also not responsible for updating this report if the site conditions change.

GHD excludes and disclaims all liability for all claims, expenses, losses, damages and costs, including indirect, incidental or consequential loss, legal costs, special or exemplary damages and loss of profits, savings or economic benefit, DELWP may incur as a direct or indirect result of the GHD Baseflow Field Work Database 2016, for any reason being inaccurate, incomplete or incapable of being processed on DELWP’s equipment or systems or failing to achieve any particular purpose. To the extent permitted by law, GHD excludes any warranty, condition, undertaking or term, whether express or implied, statutory or otherwise, as to the condition, quality, performance, merchantability or fitness for purpose of the GHD Baseflow Field Work Database 2016. GHD does not guarantee that the GHD Baseflow Field Work Database 2016 is free of computer viruses or other conditions that may damage or interfere with data, hardware or software with which it might be used. DELWP absolves GHD from any consequence of DELWP’s or other person’s use of or reliance on, the GHD Baseflow Field Work Database 2016.

vi | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Table of contents

Background ...... i Project objectives ...... i Scope of Work...... ii Previous Work...... ii Field Work ...... iii Revised Baseflow Estimates...... iv Effect of Coal Seam Gas Extraction on Baseflow...... v Conclusions and Recommendations ...... v

1. Introduction...... 1 1.1 Project background...... 1 1.2 Project objectives...... 2 1.3 Project scope ...... 2

2. Field Work Plan...... 4 2.1 Background...... 4 2.2 Thomson River from Cowwarr to Wandocka...... 5 2.3 Macalister River between Glenmaggie and Maffra Weir ...... 6 2.4 Moe Drain / Latrobe River (upstream of Lake Narracan) ...... 6 2.5 Field Sampling Condition Criteria ...... 10 3. Field Work Results ...... 11 3.1 Thomson River...... 11 3.2 Macalister River ...... 15 3.3 Latrobe River ...... 18

4. Revised Baseflow Estimates...... 23 4.1 Introduction ...... 23 4.2 Thomson River...... 24 4.3 Macalister River ...... 27 4.4 Latrobe River ...... 30

5. Validation of Previous Baseflow Estimates...... 33 5.1 Introduction ...... 33 5.2 Recommendations ...... 37

6. Effect of coal seam gas extraction on baseflow...... 39 6.1 Background...... 39 6.2 Coal Seam Gas studies ...... 39 6.3 Historic groundwater extractions ...... 40 6.4 Conclusions ...... 41

7. Conclusions and Recommendations ...... 44 7.1 Field Sampling ...... 44 7.2 Revised baseflow estimates ...... 45

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | vii 7.3 Coal seam gas impact assessment...... 47

8. References...... 48

Table index

Table 1 Thomson Catchment Round 1 Field Results...... 11

Table 2 Thomson Catchment Round 2 Field Results...... 12

Table 3 Thomson Catchment Round 3 Field Results...... 13

Table 4 Macalister Catchment Round 1 Field Results ...... 15

Table 5 Macalister Catchment Round 2 Field Results ...... 15

Table 6 Macalister Catchment Round 3 Field Results ...... 16

Table 7 Latrobe River Catchment Round 1 Field Results ...... 18

Table 8 Latrobe River Catchment Round 2 Field Results ...... 19

Table 9 Latrobe River Catchment Round 3 Field Results ...... 20

Table 10 Moe Drain Site 3– Water Quality Results (Round 3 only) ...... 20

Table 11 226402A Moe Drain @ Trafalgar (Site 4) – Water Quality Results (Round 3 only) ...... 21

Table 12 Broader Reach Scale EC Mass Balance Results for the Macalister River - using only sampling data from permanent gauging station locations (from Stage 1) ...... 33

Table 13 Sub-Reach Scale EC Mass Balance Results for the Macalister River - using recent field sampling data...... 34

Table 14 Broader Reach Scale EC Mass Balance Results for the Macalister River - using chainage-based interpolation of diverted water EC...... 34

Table 15 Broader Reach Scale EC Mass Balance Results for the Macalister River - using measured diverted water EC ...... 35

Table 16 Revised Equation Broader Reach Scale EC Mass Balance Results for the Macalister River - using only sampling data from permanent gauging station locations...... 35

Table 17 Revised Equation Sub-Reach Scale EC Mass Balance Results for the Macalister River - using recent field sampling data ...... 36

Table 18 Revised Equation Broader Reach Scale EC Mass Balance Results for the Macalister River - using only sampling data from permanent gauging station locations...... 36

Table 19 Recommended Revised Method Results: Sub-Reach Scale EC Mass Balance Results for the Macalister River - using recent field sampling data...... 37

Table 20 Comparison of baseflow contribution best estimates and uncertainty range for the Macalister River ...... 37

Table 21 Average and range in groundwater extraction from the Gippsland basin over the period 2000 – 2015...... 40

viii | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Figure index

Figure 1 Catchment Overview...... 3

Figure 2 Field Monitoring Locations: Thomson River ...... 7

Figure 3 Field Monitoring Locations: Macalister River...... 8

Figure 4 Field Monitoring Locations - Moe Drain / Latrobe River ...... 9

Figure 5 Field sampling results – Thomson River Catchment ...... 14

Figure 6 Field sampling results – Macalister River catchment ...... 17

Figure 7 Field sampling results – Latrobe River catchment...... 22

Figure 8 Flow and EC accretion profiles - Thomson River Catchment...... 25

Figure 9 Inferred baseflow conditions – Thomson River Catchment...... 26

Figure 10 Flow and EC accretion profiles - Macalister River Catchment ...... 28

Figure 11 Inferred baseflow conditions – Macalister River Catchment...... 29

Figure 12 Flow and EC accretion profiles - Latrobe River Catchment...... 31

Figure 13 Inferred baseflow conditions – Latrobe River Catchment...... 32

Figure 14 Potential impacts on surface water ecosystems from possible coal seam gas development (Figure 45 of DELWP, 2015)...... 39

Figure 15 Historic groundwater pumping from the Gippsland basin (Financial Year 1960 – 2015)...... 40

Figure 16 Groundwater levels at 52809...... 42

Figure 17 Groundwater levels at 103811...... 43

Appendices

Appendix A – Sampling Locations

Appendix B – Field Results

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | ix

1. Introduction

1.1 Project background

The Department of Environment, Land, Water and Planning (DELWP) previously undertook two projects to fill information gaps on priority Groundwater Dependent Ecosystems (GDE) – baseflow dependent rivers and wetlands. These projects, completed by GHD, developed a methodology to:

 establish where groundwater interaction occurs with rivers and wetlands;  quantify the groundwater contribution to the waterway where interaction occurs;

 identify associated high value environmental assets; and

 assess the risk to these environmental assets from groundwater extraction. A discussion paper was prepared by GHD in 2012 to appraise methods for quantifying regional groundwater discharge to streams (as “baseflow”) throughout Victoria. This paper formed the basis of a workshop to decide which method would best be suited to quantifying groundwater- surface water interactions for high-risk baseflow-dependent waterways throughout Victoria. The adopted baseflow estimation method involved digital baseflow filtering “trained” to environmental tracer data – primarily electrical conductivity. A series of recommendations for trialling and implementing the recommended method were provided at the end of the discussion paper.

A pilot project was undertaken by GHD in 2012 - 2013 for five Victorian rivers (GHD, 2013a). The year-long pilot established an innovative method that characterised groundwater contributions to the upper Loddon, upper Moorabool, lower Ovens, lower Mitchell and lower Thomson-Macalister Rivers. These results were used to assess the risk of groundwater extraction to the environmental values that those rivers support. This project was expanded in 2013 (GHD, 2013b) to a further eight Victorian rivers using the same method. Rivers assessed were the Latrobe, Barwon, Gellibrand, Glenelg, Hopkins, Yea, Seven Creeks and Deep Creek. As for the pilot method, the results were used to assess the risk of groundwater extraction to the environmental values that those rivers support.

The results from these projects were incorporated into a state-wide tool (Victorian Water Asset Register – VWAR) that flags areas where environmental values are potentially at risk from groundwater extraction (both current and future). This will assist waterway and environmental managers to manage risks to high priority GDEs.

A scientific review of both baseflow studies (GHD, 2013a; GHD, 2013b) made a number of recommendations to refine the method and quantification used to determine the risk of combined surface water and groundwater extractions to significant environmental values. These recommendations are reviewed and incorporated into this current project. GHD, in partnership with Groundwater Logic, has been contracted by DELWP to assess the accuracy of baseflow estimates for the Latrobe, Thomson-Macalister and Mitchell River catchments.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 1 1.2 Project objectives

The primary objective of this project is to improve the accuracy and reliability of the baseflow estimates along the Latrobe, Thomson-Macalister and Mitchell Rivers.

The objective of this project is to improve understanding of the degree and nature of interaction between rivers and groundwater in the Gippsland region, and to help understand potential impacts of coal mining, coal seam gas developments and other water uses on water-dependent environmental assets. The outputs of the work will improve the accuracy of, and confidence in, analysis of the dependency of flows on groundwater and improve technical basis on the likelihood of direct, indirect and cumulative impacts of water use on baseflows.

The scope of this project is to implement the recommendations from the scientific review of the method developed by GHD (GHD, 2013a; GHD, 2013b) for characterising groundwater contributions to rivers.

One of the key outcomes from this study is to provide a tiered framework for the application of the baseflow estimation method(s) most suitable for difference classes of reaches, such as losing reaches, gaining reaches and regulated reaches.

The project will apply the refined method to three high value Gippsland river systems (Figure 1):

 Latrobe River (Latrobe River to Kilmany South);

 Thomson-Macalister River system (Thomson River from Cowwarr Weir to Bundalaguah; Macalister River from Lake Glenmaggie to the confluence with the Thomson River); and

 Mitchell River (Glenaladale to Rosehill).

The project has been completed in two stages:

 Stage 1: Review groundwater contributions to rivers  Stage 2: Targeted ground-truthing of existing data (data verification)

This report documents the Stage 2 assessment.

1.3 Project scope

Following on from the work completed in 2013 (GHD, 2013a; GHD, 2013b), the scope of work for Stage 2 of this project includes:  Develop a field work plan to undertake monitoring at targeted ground-truthing sites;

 Undertake proposed field work at targeted locations and monitoring periods, based on the field work plan;  Refine the baseflow analysis and interstation analysis based on the ground-truthing data; and

 Undertake high level analysis to assess potential effects that coal seam gas extraction may have on groundwater – surface water interactions.

2 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 320,000 340,000 360,000 380,000 400,000 420,000 440,000 460,000 480,000 500,000 520,000 540,000 560,000 580,000 600,000

SHEPPARTON WODONGA ALBURY 0 0

0 WANGARATTA 0 0 0 , , 0 0 0 0 9 9

, BENDIGO BEGA , 5 5

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T Y 225247 T E 225232 A R N S J I 226007 R L I R V I E V R E 226216 R 0 L 0 0 A 0

0 T 0 , RO , 0 B 226227 0 8 E 226228 8

7 R 7 , IV 226033 ,

5 M E 5 O R E 226021 226005 R IV E R 226408 Latrobe River 226415

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320,000 340,000 360,000 380,000 400,000 420,000 440,000 460,000 480,000 500,000 520,000 540,000 560,000 580,000 600,000

Major Water Course Surface Water Job Number 31-32709 Paper Size A3 Department of Environment, Land, Water & Planning Gauges (Assessed) Revision A 0 4 8 16 24 32 Latrobe River Gippsland River Baseflow Assessment Date 27 May 2015 Mitchell River Kilometers

Map Projection: Transverse Mercator Thomson Macalister Catchment Overview Horizontal Datum: GDA 1994 River Grid: GDA 1994 MGA Zone 55 Baseflow Catchments Figure 1 G:\31\32709\GIS\Maps\Deliverables\3132709_KBM_A3L.mxd [KBM: 3] 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com © 2015. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015. Created by: adrummond 2. Field Work Plan

2.1 Background

It is recognised that while long-term data collection is the optimal approach for refining baseflow estimates, it is not possible to apply in this project given the short time-frame and budgetary constraints. Improved baseflow estimates are important for long-term groundwater-surface water management and provide valuable context in a range of water management issues, such as assessing the impact of groundwater extraction on environmental flows in priority reaches and groundwater dependent ecosystems. The field work plan developed for Stage 2 of this project focussed on activities that can be undertaken within the time and budget available, and could potentially achieve an improvement in the baseflow separation accuracy or uncertainty. The field sampling, analysis methods and interpretations applied in this study also form a useful template for ongoing monitoring and investigations. While highly localised studies and field data do not broadly inform the regional-scale conceptualisation and analysis of groundwater-surface water interactions, they do provide a valuable basis for constraining the more regional-scale estimates and thereby improving the approach to and confidence in more broad-scale approaches.

The targeted sites for field assessment were discussed between the relevant authorities (CMAs, SRW and DELWP) to prioritise the field assessments on reaches which will deliver most value to stakeholders, while meeting the requirements of the Gippsland CMAs and the Bioregional Assessment Program.

2.1.1 General Field Monitoring Options

The three main field activities proposed in this study include: flow and EC accretion profiling, EC and flow logging, and groundwater sampling. It is acknowledged that the project budget does not allow for all of these to be applied to all reaches; therefore a decision was made on the best use of resources and the preferred location of these activities.

The key field data collection options which could be implemented to assist in ground-truthing of the baseflow estimates are summarised below:  Flow and EC accretion profiling: This activity consists of measuring streamflow and sampling EC at key points along the reach of interest, allowing a reach to be broken up into various sub-reaches. This method provides additional detail within a reach that has already been assessed using the baseflow estimation method, and may identify where the main discharges of baseflow occur spatially.  Groundwater potentiometry and EC sampling: This activity would provide additional data to refine the groundwater EC end members used to estimate baseflow. The potentiometry data would provide qualitative information, indicating whether the river is gaining or losing at a particular location. However, there are large practical uncertainties with respect to accessing private bores and the time required to obtain groundwater samples. Consequently, there is potential for this to be an expensive activity relative to the benefit of the additional data.  Installation of temporary EC loggers at existing streamflow gauging locations: This activity has a moderate cost and short to medium duration and would allow the collection of continuous EC data at sites that currently only have monthly or quarterly water quality sampling. This would provide significantly more data to calibrate the baseflow estimation method, particularly the reach-scale mass balance that requires EC data on the same day at multiple gauges.

4 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709  Installation of temporary flow gauging stations with EC loggers: This option would enable a greater spatial coverage of the baseflow estimation method; however, given the large installation costs, it is perhaps more appropriate that this be undertaken as part of a longer term program.

A targeted field work plan to undertake flow and EC accretion profiling was developed in consultation with DELWP, WGCMA and SRW, based on the key data gaps identified in Stage 1 (GHD, 2015), and the key reaches of interest. The key reaches include:

 Thomson River from Cowwarr to Wandocka;

 Moe Drain / Latrobe River upstream of Lake Narracan; and  Macalister River between Glenmaggie and Maffra Weir.

Sampling locations were selected to monitor immediately upstream and downstream of key discharge points to the main reach (i.e. irrigation drains, tributaries, etc.), and where possible to promote site accessibility (i.e. close to roads and tracks, accessible via public land). They were also selected to avoid any site specific issues identified by Thiess (i.e. flooding of the Maffra Weir Pool during the irrigation season). It was decided that data would be collected for three sampling rounds over the study period, covering different seasons and regulated influences (irrigation releases):

 Sampling Round 1: Spring 2015 (09/09/2015 – 28/09/2015). Capture flows at the start of the irrigation season.

 Sampling Round 2: Summer 2016 (12/01/2016 – 05/02/2016): Capture summer low flows.  Sampling Round 3: Autumn 2016 (12/04/2016 – 17/05/2016): Capture flows outside of irrigation season.

The sampling locations are outlined in the sections below.

2.2 Thomson River from Cowwarr to Wandocka

Anecdotal evidence suggests that the Thomson River between Cowwarr and Wandocka is a seasonal flow ‘losing’ reach. Surface water flow and EC accretion profiling will provide additional evidence to confirm whether or not this reach is in fact 'losing'. It was anticipated that further investigation could be useful to help assess future local water management plans for this region.

Nine sampling locations were initially selected along the Thomson River between Cowwarr and Wandocka, shown on Figure 2, and summarised below:

1. Thomson River U/S Cowwarr Weir (225231A) 2. Thomson River @ Timber Weir (225228A)

3. Rainbow Creek D/S Cowwarr Weir (225227A)

4. Rainbow Creek U/S Thomson River 5. Thomson River D/S Stoney Creek

6. Thomson River U/S Back Creek

7. Thomson River U/S Rainbow Creek 8. Thomson River D/S Rainbow Creek (225243A)

9. Thomson River at Wandocka (225212)

It is noted that the sampling locations were indicative, with minor adjustments made in the field to identify locations with adequate geomorphology for gauging and EC/temperature sampling.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 5 2.3 Macalister River between Glenmaggie and Maffra Weir

Five indicative sampling locations were selected along the Macalister River between Glenmaggie and Maffra Weir, shown on Figure 3, and summarised below:

1. 225204D Macalister River D/S Glenmaggie T/G

2. Macalister River U/S Newry Drain (Banana Bridge) 3. Macalister River U/S Maffra Weir Pool (Bellbird Corner)

4. 225242A Macalister River D/S Maffra Weir T/G

5. 225247A Macalister River @ Riverslea There is a high density of groundwater extractions within this region of the Macalister River, from the Wa De Lock GMA and the Rosedale GMA. It was anticipated that spot sampling along this reach would provide additional information to ground-truth existing baseflow estimates, and this information could be used to support future local water planning studies in this region.

2.4 Moe Drain / Latrobe River (upstream of Lake Narracan)

The WGCMA and SRW have expressed interest in investigating the interaction between groundwater and surface water within the Moe Groundwater Management Area. The baseflow separation method was not applied along the Moe River in previous studies due to data limitations. It was anticipated that targeted field work within this region would provide estimates of baseflow which can be used as a baseline for future assessments. Twelve indicative sampling locations were selected along the Moe Drain / Latrobe River upstream of Lake Narracan, shown on Figure 4, and summarised below:

1. 226209B Moe River @ Darnum (Site 1) 2. Moe Drain Site 2 (Start of drain)

3. Moe Drain Site 3

4. 226402A Moe Drain @ Trafalgar East (Site 4) 5. Moe River U/S Latrobe River (Site 5)

6. 226204A Latrobe River @ Willow Grove

7. Latrobe River U/S Moe Drain 8. 226218A Narracan Creek @ Thorpdale

9. 226021A Narracan Creek @ Moe

10. 226216A Tanjil River @ Tanjil South 11. Tanjil River U/S Latrobe River

12. Latrobe River at U/S Lake Narracan (Becks Bridge)

6 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 470,000 475,000 480,000 485,000 490,000

M LAKE A GLENMAGGIE C RR ALISTE IV E R 5,800,000 5,800,000 TRARALGON

S to n e B y a Thomson River C ck r C U/S Cowwarr e r e ee Weir (225231A) k k

Thomson River D/S Stoney Creek

Thomson River Thomson River U/S Rainbow Creek @ Timber Weir

5,795,000 Thomson 5,795,000 (225228A) River U/S RIVER THOMSON Rainbow Creek Back Creek Thomson River D/S Cowwarr @ Wandocka Weir (225227A) (225212A)

Thomson River Rainbow Creek D/S Rainbow Creek U/S Thomson River (225243A) RAINBOW CREEK 5,790,000 5,790,000

470,000 475,000 480,000 485,000 490,000

Major Water Area Field Sampling Job Number 31-32709 Paper Size A3 Department of Environment, Land, Water & Planning Location Revision B 0 0.5 1 2 Major Watercourse Gippsland River Baseflow Assessment Date 01 Mar 2016 Kilometers Thomson Macalister River Catchment Map Projection: Transverse Mercator Field Monitoring Locations Horizontal Datum: GDA 1994 Grid: GDA 1994 MGA Zone 55 Thomson River Figure 2 G:\31\32709\GIS\Maps\Deliverables\3132709_KBM_A3L_Stage2_v2.mxd [KBM: 22] 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by: adrummond 475,000 480,000 485,000 490,000 495,000 500,000 LAKE GLENMAGGIE E CREEK GLENMAGGI

225204D Macalister River D/S Glenmaggie T/G 5,805,000 5,805,000

LAKE GLENMAGGIE

MA CAL IS T E R RIV TRARALGON ER

Macalister River U/S Maffra Weir Pool (Bellbird Corner) Macalister River U/S Newry Drain (Banana Bridge) 5,800,000 5,800,000

MAFFRA

225242A Macalister River D/S Maffra Weir T/G 5,795,000 5,795,000

ON RIVER MS THO

K RAINBOW CREE

225247A Macalister River @ Riverslea

475,000 480,000 485,000 490,000 495,000 500,000

Major Water Area Field Sampling Job Number 31-32709 Paper Size A3 Department of Environment, Land, Water & Planning Location Revision B 0 0.5 1 2 Major Watercourse Gippsland River Baseflow Assessment Date 01 Mar 2016 Kilometers Thomson Macalister River Catchment Map Projection: Transverse Mercator Field Monitoring Locations Horizontal Datum: GDA 1994 Grid: GDA 1994 MGA Zone 55 Macalister River Figure 3 G:\31\32709\GIS\Maps\Deliverables\3132709_KBM_A3L_Stage2_v2.mxd [KBM: 23] 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by: adrummond 405,000 410,000 415,000 420,000 425,000 430,000 435,000 440,000 445,000

TANJIL RIVER

BLUE MOONDARRA ROCK RESERVOIR LAKE

TRARALGON T R Y 226204A I E

5,785,000 V R 5,785,000 E S Latrobe River R

@ Willowgrove T

226216A Tanjil L

River @ R I V

Tanjil South E LA R TR OB E RI VE Tanjil River R U/S Latrobe River 5,780,000 5,780,000

Latrobe River Latrobe River U/S Moe Drain U/S Lake Narracan (Becks Bridge)

Moe River U/S LAKE Latrobe River NARRACAN WARRAGUL (Site 5)

LA TROBE 226402A Moe Drain RIVER @ Trafalgar 5,775,000 (Site 4) 5,775,000 Moe Drain Moe Drain 226021A Narracan Site 2 (Start Site 3 MOE Creek @ Moe of Drain) MOE DRAIN

MOE RIVER

226209B Moe R EA B EEK River @ Darnum CR (Site 1) 5,770,000 5,770,000

L L E W R R E O IV M R

BEAR CREEK 226218A

5,765,000 Narracan Creek 5,765,000 @ Thorpdale

AN NARRAC CREEK

405,000 410,000 415,000 420,000 425,000 430,000 435,000 440,000 445,000

Major Water Area Field Sampling Job Number 31-32709 Paper Size A3 Department of Environment, Land, Water & Planning Location Revision B 0 0.5 1 2 3 4 Major Watercourse Gippsland River Baseflow Assessment Date 01 Mar 2016 Kilometers Latrobe River Catchment Map Projection: Transverse Mercator Field Monitoring Locations Horizontal Datum: GDA 1994 Grid: GDA 1994 MGA Zone 55 Latrobe River Figure 4 G:\31\32709\GIS\Maps\Deliverables\3132709_KBM_A3L_Stage2_v2.mxd [KBM: 21] 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by: adrummond 2.5 Field Sampling Condition Criteria

The objective of this study is to measure the groundwater contributions along river reaches by gauging flows and EC at key locations along the river. While it may be possible to measure these under almost all conditions, the constraint that sampling was limited to three rounds (designed to represent different seasons) meant that it was critical to select conditions that would give the most accurate and representative results. To identify suitable conditions for undertaking the streamflow gauging and EC sampling, a number of criteria were evaluated prior to commencing field investigations, and are outlined below.

Safety The streamflow must be suitably low, to permit safe access to undertake flow gauging. The streamflow threshold varies depending on the site to be sampled. The hydrographer is able to make an assessment of the suitability for gauging. Other safety consideration may further limit field sampling.

River Operation Periods associated with large reservoir releases (such as flood mitigation type releases) should be avoided, as these releases are likely to obscure the more subtle groundwater surface water interactions.

Streamflow Rate As a generalisation, it is also possible to more accurately gauge streamflow at lower flow rates. While this depends on the hydraulic properties of the site, the absolute error is likely to grow as flow increases, where at high flows this error may exceed the interstation groundwater contribution. This study adopted a broad target to aim to undertake sampling when the flow rate was below the median flow for the month of year. However, it is important to note that other factors (such as regulation and recent rainfall) are likely to have a greater impact on the results.

Streamflow Trends Sampling during peak streamflow following large rainfall events should be avoided for a number of reasons. The streamflow following rainfall events is likely to be high flows which have an associated higher uncertainty in the flow measurement, a relatively low proportion of groundwater contribution, first flush of salts, and high bank storage effects. It is desirable to undertake sampling as long after the peak as is practical so that these short term effects have reduced and groundwater has begun to more steadily contribute to flow.

Streamflow Profile (Longitudinal) Field monitoring should be undertaken when the difference in streamflow between sites is relatively stable. If the streamflow is dropping rapidly as a peak of water travels down the river (from rainfall events or regulation) then it will not be possible to make a suitable comparison between sites.

Forecast Rainfall Field monitoring should be undertaken when forecast rainfall over the proposed work period is 5 mm or less. This is especially important for the Thomson and Latrobe River catchments which require multiple days to complete sampling of the full suite of sites. However, it is noted that if another significant constraint is likely to more significantly impact the proposed work period, then a forecast of up to 10 mm may be acceptable. If the forecast is clear then it may be best to wait as long as possible, to allow other aspects to improve as necessary.

10 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 3. Field Work Results

To date, two of the three rounds of field sampling have been undertaken at the sampling locations as per the field work plan, discussed in Section 2. The first sampling round was undertaken in September (9th September until 28th September 2015) to capture the spring baseflows at the start of the irrigation season. The second sampling round was undertaken in mid-January to early February (12th January – 5th February 2016) to capture the summer baseflow conditions. The third round of field monitoring is scheduled to be completed in late May 2016 to capture the autumn base flow conditions following the end of the irrigation season. Site photographs captured by Thiess during the spring sampling round showing the site conditions are contained in Appendix A.

3.1 Thomson River

Figure 5 summarises the streamflow and EC monitoring results for the Thomson River catchment (from Cowwarr to Wandocka), with the raw data obtained from Thiess contained in Appendix B.

Table 1 summarises the field results for the Thomson River taken for the first round of monitoring in spring. The following field notes were obtained when sampling:

1. Southern Rural Water commented that Cowwarr Channel was running at a constant rate of 67.2 ML/day (09/09/2015);

2. Logger at visit Cowwarr Head Gauge (HG): 64.927 ML/day and Tail Gauge (TG) 0.139 ML/day; and 3. Additional site information collected for the Stoney Creek Crossing and Syphon Outfall. Table 1 Thomson Catchment Round 1 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 Thomson River U/S Cowwarr Weir 9/09/2015 368.5 73 Overcast / (225231A) Showers Thomson River @ Timber Weir (225228A) 9/09/2015 262.3 73 Overcast / Showers Thomson River D/S Stoney Creek 9/09/2015 293.0 77 Overcast / Showers Rainbow Creek D/S Cowwarr Weir 9/09/2015 56.7 74 Overcast / (225227A) Showers Thomson River U/S Back Creek 9/09/2015 290.4 78 Overcast / Showers Stoney Creek Crossing 9/09/2015 3 142 Flow est. Day 2 Rainbow Creek @ U/S Thomson River 10/09/2015 67.4 101 Fine Thomson River @ U/S of Rainbow Creek 10/09/2015 266.5 83 Fine Thomson River @ U/S of Rainbow Creek 10/09/2015 269.3 83 Confirmation Meas. Thomson River D/S Rainbow Creek 10/09/2015 385.9 84 Fine (225243A) Thomson River @ Wandocka (225212A) 10/09/2015 404.2 92 Fine Thomson River U/S Back Creek 10/09/2015 251.5 78 Fine

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 11 Site Date Streamflow EC Comments (ML/d) (uS/cm) Syphon Outfall 10/09/2015 10 - 20 62 Flow est.

Table 2 summarises the field results for the Thomson River taken for the second round of monitoring in summer. The following field notes were obtained when sampling:

1. Southern Rural Water (D. Johnson) commented that Cowwarr Channel was running at a rate of 20 – 23 ML/day;

2. Logger at visit Cowwarr HG: 64.927 ML/day and TG 0.139 ML/day; and

3. Additional site information collected for the Stoney Creek Crossing and Syphon Outfall. Table 2 Thomson Catchment Round 2 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 Thomson River U/S Cowwarr Weir 12/01/2016 231.6 83 Weather Fine (225231A) Thomson River @ Timber Weir (225228A) 12/01/2016 126.6 91 Weather Fine Thomson River D/S Stoney Creek 12/01/2016 136.6 99 Weather Fine Rainbow Creek D/S Cowwarr Weir 12/01/2016 57.5 91 Weather Fine (225227A) Thomson River U/S Back Creek 12/01/2016 110.8 100 Weather Fine Stoney Creek Crossing 12/01/2016 2 Flow est. Day 2 Rainbow Creek @ U/S Thomson River 13/01/2016 52.9 108 Weather Fine Thomson River @ U/S of Rainbow Creek 13/01/2016 117.5 103 Weather Fine Thomson River D/S Rainbow Creek 13/01/2016 210.4 100 Weather Fine (225243A) Thomson River @ Wandocka (225212A) 13/01/2016 161.5 107 Weather Fine Thomson River U/S Back Creek 13/01/2016 121.0 98 Weather Fine Syphon Outfall 13/01/2016 40 Flow est.

12 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Table 3 summarises the field results for the Thomson River taken for the third round of monitoring in summer. The following field notes were obtained when sampling:

1. Southern Rural Water (D. Johnson) commented that 6 ML/day was being released down the Cowwarr Channel

2. Syphon Outfall was estimated to have a flow of 30 to 40 ML/day at 11:30 AM and 5 to 10 ML/day at 12:50 PM. Table 3 Thomson Catchment Round 3 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 Thomson River U/S Cowwarr Weir 12/04/2016 171.2 67 Overcast (225231A) Thomson River U/S Cowwarr Weir 12/04/2016 165.7 67 Overcast (225231A) Thomson River @ Timber Weir (225228A) 12/04/2016 105.6 67 Overcast Thomson River D/S Stony Creek 12/04/2016 106.7 68 Overcast Rainbow Creek D/S Cowwarr Weir 12/04/2016 48.0 67 Overcast (225227A) Thomson River U/S Back Creek 12/04/2016 110.6 70 Overcast Stoney Creek Crossing 12/04/2016 No flow Day 2 Rainbow Creek @ U/S Thomson River 13/04/2016 50.8 87 Overcast Thomson River @ U/S of Rainbow Creek 13/04/2016 102.7 71 Overcast Thomson River D/S Rainbow Creek (225243A) 13/04/2016 187.3 75 Sunny Thomson River @ Wandocka (225212A) 13/04/2016 188.2 72 Overcast Thomson River U/S Back Creek 13/04/2016 107.6 70 Overcast Syphon Outfall 13/04/2016 Variable 65

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 13 0 0 0 0 0 0

, 460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000 505,000, 0 0 0 0 8 8 , , 5 5

Thomson River D/S Stoney Creek Thomson River U/S Back Creek Stoney Creek Crossing Date: 9/09/2015 Date: 9/09/2015 Thomson River @ Timber Weir (225228A) Date: 9/09/2015 Flow: 293ML/d Flow: 290.4ML/d Date: 9/09/2015 Flow: 3 ML/d (+/- 1 ML/d) EC: 77 uS/cm EC: 78 uS/cm Flow: 262.3ML/d *flow estimated EC: 73 uS/cm EC: 142 uS/cm Thomson River U/S Back Creek Thomson River @ U/S of Rainbow Creek

*Additional site information Date: 10/09/2015

Date: 10/09/2015 R # Flow: 2.911ML/d # Flow: 3.084ML/d E V EC: 78 uS/cm I

#0 EC: 83 uS/cm R # ER IST Thomson River @ Wandocka (225212A) L

#0 Date: 10/09/2015 A 0 # 0

0 0 M

# Flow: 4.678ML/d R 0 0 , , Thomson River U/S Cowwarr Weir (225231A) #

5 E 5

9 EC: 92 uS/cm 9 V 7 Date: 9/09/2015 I 7 , ,

5 #0 5

Flow: 368.5ML/d T HOMSON R EC: 73 uS/cm #0 #

# #0 #0#0 #0 # RAINB EEK # O W CR Rainbow Creek D/S Cowwarr Weir (225227A) Date: 9/09/2015 #0 Flow: 56.7ML/d Rainbow Creek @ U/S Thomson River Thomson River D/S Rainbow Creek (225243A) EC: 74 uS/cm Date: 10/09/2015 Date: 10/09/2015 Flow: 0.78ML/d Flow: 4.466ML/d EC: 101 uS/cm EC: 84 uS/cm

460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000 505,000 0 0 0 0 0 0

, 460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000 505,000, 0 0 0 0 8 8 , , 5 5 Stoney Creek Crossing Date: 12/01/2016 Thomson River D/S Stoney Creek Date: 12/01/2016 Flow: 2ML/d* Thomson River U/S Back Creek Thomson River @ Timber Weir (225228A) *Flow estimated Flow: 136.6ML/d Date: 12/01/2016 HOMSO Date: 12/01/2016 Additional site information EC: 99 uS/cm Thomson River @ U/S of Rainbow Creek T N RIV Flow: 110.8ML/d E Flow: 126.6ML/d Date: 13/01/2016 R EC: 100 uS/cm EC: 91 uS/cm Flow: 117.5ML/d

Thomson River U/S Back Creek EC: 103 uS/cm # R

Date: 13/01/2016 E

# V #0 Flow: 121ML/d I R

EC: 98 uS/cm ER # IST L

Thomson River D/S Rainbow Creek (225243A) A

#0 Date: 13/01/2016 A

0 Thomson River U/S Cowwarr Weir (225231A) 0

0 # 0 M

# Flow: 210.4ML/d 0 0

, Date: 12/01/2016 , 5 # 5

9 EC: 100 uS/cm 9

7 Flow: 231.6ML/d 7 , ,

5 EC: 83 uS/cm #0 5 #0 #

##0 ##0#0#0 # RAINB EEK O W CR Rainbow Creek D/S Cowwarr Weir (225227A) # Date: 12/01/2016 #0 Flow: 57.5ML/d Thomson River @ Wandocka (225212A) EC: 91 uS/cm Rainbow Creek @ U/S Thomson River Date: 13/01/2016 Date: 13/01/2016 Flow: 52.9ML/d Flow: 161.5ML/d EC: 108 uS/cm EC: 107 uS/cm

460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000 505,000 0 0 0 0 0 0

, 460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000 505,000, 0 0 0 0 8 8 , , 5 5

Stoney Creek Crossing Thomson River D/S Stoney Creek Date: 12/04/2016 Date: 12/04/2016 Thomson River U/S Back Creek Thomson River @ Timber Weir (225228A) Flow: 106.7ML/d Flow: No flow Date: 12/04/2016 HOMSO Date: 12/04/2016 EC: 68 uS/cm Thomson River @ U/S of Rainbow Creek T N RIV Flow: 110.6ML/d E Flow: 105.6ML/d Date: 13/04/2016 R EC: 70 uS/cm EC: 67 uS/cm Flow: 102.7ML/d

Thomson River U/S Back Creek EC: 71 uS/cm Thomson River U/S Cowwarr Weir (225231A) # R

Date: 13/04/2016 E Date: 12/04/2016 # # V #0 Flow: 107.6ML/d I Flow: 165.7ML/d R

EC: 70 uS/cm ER EC: 67 uS/cm # IST L

Thomson River D/S Rainbow Creek (225243A) A

#0 Date: 13/01/2016 A

0 Thomson River U/S Cowwarr Weir (225231A) 0 #

0 # 0

Flow: 187.3ML/d M 0 0

, Date: 12/04/2016 , 5 # 5

9 EC: 75 uS/cm 9

7 Flow: 171.2ML/d 7 , ,

5 EC: 67 uS/cm #0 5 #0 #

##0 ##0#0#0 # RAINB EEK O W CR Rainbow Creek D/S Cowwarr Weir (225227A) # Date: 12/04/2016 #0 Flow: 48ML/d Thomson River @ Wandocka (225212A) EC: 67 uS/cm Rainbow Creek @ U/S Thomson River Date: 13/04/2016 Date: 13/04/2016 Flow: 50.8ML/d Flow: 188..2ML/d EC: 87 uS/cm EC: 72 uS/cm

460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000 505,000

Field Sampling River Department of Environment Land Water and Planning Job Number 31-32709 Paper Size A3 #0 Location Revision A 0 0.5 1 2 3 4 Stream Gippsland Rivers Baseflow Assessment Thomson Macalister Date 31 May 2016 Channel Kilometers River Catchment

Map Projection: Transverse Mercator Drain/Channel/Ot... Field Monitoring Results Horizontal Datum: GDA 1994 o Major Water Area Grid: GDA 1994 MGA Zone 55 Thomson River Figure 5 G:\31\32709\GIS\Maps\Deliverables\FieldResults\3132709_KBM_A3L_Stage2_FieldResults_Thomson.mxd 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by:adrummond 3.2 Macalister River

Figure 6 summarises the streamflow and EC monitoring results for the Macalister River catchment (from Glenmaggie to Riverslea), with the raw data obtained from Thiess contained in Appendix B.

Table 4 summarises the field results for the Macalister River taken for the first round of monitoring in spring. The following field notes were obtained when sampling:

1. Small outflow into Macalister River at Maffra Weir D/S measurement section, estimated at 2-3 ML/d, EC recorded at 240 EC and Temperature 24.0 C;

2. Outflow from Lake Glenmaggie had been cut back 3 days prior to measurements;

3. SRW Estimate 60 ML/d flowing down the Eastern Channel from Maffra Weir; and 4. Possibly significant inflows into the Macalister River between Maffra Weir and Riverslea via the Serpentine Creek. Table 4 Macalister Catchment Round 1 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 225204D Macalister River D/S 28/09/2015 108.5 49.3 Overcast Glenmaggie T/G Macalister River U/S Newry Drain 28/09/2015 123.1 63.9 Overcast (Banana Bridge) Macalister River U/S Maffra Weir Pool 28/09/2015 150.6 109.5 Overcast (Bellbird Corner) 225242A Macalister River D/S Maffra 28/09/2015 98.1 78.5 Overcast Weir T/G 225247A Macalister River @ 28/09/2015 129.6 143.1 Overcast Riverslea 225204D Macalister River D/S 28/09/2015 108.5 49.3 Overcast Glenmaggie T/G

Table 5 summarises the field results for the Macalister River taken for the second round of monitoring in spring. No additional field notes were made during monitoring. Table 5 Macalister Catchment Round 2 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 225204D Macalister River D/S 14/01/2016 256.2 62 Weather is Fine Glenmaggie T/G Macalister River U/S Newry Drain 14/01/2016 244.7 60 Weather is Fine (Banana Bridge) Macalister River U/S Maffra Weir Pool 14/01/2016 258.2 80 Weather is Fine (Bellbird Corner) 225242A Macalister River D/S Maffra 14/01/2016 93.3 110 Weather is Fine Weir T/G 225247A Macalister River @ 14/01/2016 129.1 209 Weather is Fine Riverslea 225204D Macalister River D/S 14/01/2016 256.2 62 Weather is Fine Glenmaggie T/G

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 15 Table 6 summarises the field results for the Macalister River taken for the third round of monitoring in spring. The following field notes were obtained when sampling:

1. The pipe and gate 2 was closed at Maffra Weir 2. Small outflow into Macalister River at Maffra Weir D/S measurement section, estimated at 2-3 ML/d, EC recorded at 534 EC and Temperature 24.7°C

3. Flow in Serpentine Creek at Singletons was estimated between 3 and 5 ML/day, EC and temperature recorded was 374 and 18.3°C respectively.

4. Flow in Carter Creek (U/S Bellbird Corner) was estimated to be 2 ML/day, EC and temperature recorded was 560 and 16.5°C respectively. 5. SRW noted irrigation supply of 10 ML/day downstream of Banana Bridge. Table 6 Macalister Catchment Round 3 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 225204D Macalister River D/S 14/04/2016 142.3 66 Sunny Glenmaggie T/G Macalister River U/S Newry Drain 14/04/2016 127.2 75 Sunny (Banana Bridge) Macalister River U/S Maffra Weir Pool 14/04/2016 143.9 90 Overcast (Bellbird Corner) 225242A Macalister River D/S Maffra 14/04/2016 62.1 110 Overcast Weir T/G 225247A Macalister River @ 14/04/2016 74.0 152 Overcast Riverslea

16 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 485,000 490,000 495,000 500,000 485,000 490,000 495,000 500,000 485,000 490,000 495,000 500,000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 , , , , 0 0 , , 0 0 0 0 0 0 1 1 1 1 1 1 8 8 8 8 , , , , 8 8 , , 5 5 5 5 5 5 225204D Macalister River D/S Glenmaggie T/G 225204D Macalister River D/S Glenmaggie T/G 225204D Macalister River D/S Glenmaggie T/G Date: 14/04/2016 Date: 14/01/2016 Date: 14/04/2016 Flow: 142.3ML/d Flow: 256.2ML/d Flow: 142.3ML/d

EC: 66 uS/cm EC: 62 uS/cm EC: 66 uS/cm

# # # # 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

, Macalister River U/S Maffra Weir Pool (Bellbird Corner) , , , Macalister River U/S Maffra Weir Pool (Bellbird Corner) 0 0 , ,

Macalister River U/S Maffra Weir Pool (Bellbird Corner) 5 5 5 5 5 5 0 0 0 0

0 0 Date: 14/04/2016 8 8

8 Date: 14/04/2016 8 #0 #0 , , , , Date: 14/01/2016 8 #0 8 , , 5 5 5 5 Flow: 143.9ML/d 5 Flow: 258.2ML/d 5 Flow: 143.9ML/d EC: 90 uS/cm EC: 80 uS/cm EC: 90 uS/cm

LAKE LAKE LAKE

GLENMAGGIE GLENMAGGIE GLENMAGGIE

# # # M # M M A A TER A A TER C IS R C L IS R A A TER L C L IS R I I V V I V

E 0 0 0 0 #0E #0 E 0 0 0 0

0 0 #0

R 0 0

R 0 0 0 0

R , , , , 0 0 , , 0 0 0 0 #0 0 0 # #0 0 0 0 # 0 ##0 0 0 8 8 8 8 , , , , 8 8 , , 5 5 5 5 5 5 Macalister River U/S Newry Drain (Banana Bridge) Macalister River U/S Newry Drain (Banana Bridge) Macalister River U/S Newry Drain (Banana Bridge) Date: 14/04/2016 Date: 14/01/2016 Date: 14/04/2016 Flow: 127.2ML/d Flow: 244.7ML/d Flow: 127.2ML/d EC: 75 uS/cm EC: 60 uS/cm EC: 75 uS/cm

# # # 225242A Macalister River D/S Maffra Weir T/G #0 225242A Macalister River D/S Maffra Weir T/G #0 225242A Macalister River D/S Maffra Weir T/G #0 Date: 14/04/2016 Date: 14/01/2016 Date: 14/04/2016 Flow: 62.1ML/d Flow: 93.3ML/d Flow: 62.1ML/d EC: 110 uS/cm EC: 110 uS/cm EC: 110 uS/cm 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 , , , , 0 0 , , 5 5 5 5 5 5 9 9 9 9 9 9 7 7 7 7 , , , , 7 7 , , 5 5 5 5 5 5

R R MS E R OMSO E HO O I V OMSO VE TH N I V T N R TH N RI R

# #0 # # #0 225247A Macalister River @ Riverslea 225247A Macalister River @ Riverslea #0 225247A Macalister River @ Riverslea 0 0 Date: 14/04/2016 0 Date: 14/04/2016 0 0 0 0 Date: 14/01/2016 0 0 0 0 0 0 0 0 0 , , , , Flow: 74ML/d 0 0 Flow: 74ML/d , , 0 Flow: 129.1ML/d 0 0 0 0 0 9 9 9 9 9 9 7 7 EC: 152 uS/cm 7 EC: 152 uS/cm 7 , , , , 7 EC: 209 uS/cm 7 , , 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 , , , , 0 0 , , 5 5 5 5 5 5 8 8 8 8 8 8 7 7 7 7 , , , , 7 7 , , 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 , , , , 0 0 , , 0 0 0 0 0 0 8 8 8 8 8 8 7 7 7 7 , , , , 7 7 , , 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 , , , , 0 0 , , 5 5 5 5 5 5 7 7 7 7 7 7 7 7 7 7 , , , , 7 7 , , 5 5 5 5 485,000 490,000 495,000 500,000 5 485,000 490,000 495,000 500,000 5 485,000 490,000 495,000 500,000

Map Projection: Transverse Mercator Drain/Channel/Ot... Field Monitoring Results Horizontal Datum: GDA 1994 o Major Water Area Grid: GDA 1994 MGA Zone 55 Macalister River Figure 6 G:\31\32709\GIS\Maps\Deliverables\FieldResults\3132709_KBM_A3P_Stage2_FieldResults_Macalister.mxd 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by:adrummond 3.3 Latrobe River

Figure 7 summarises the streamflow and EC monitoring results for the Macalister River catchment (from Glenmaggie to Riverslea), with the raw data obtained from Thiess contained in Appendix B.

Table 7 summarises the field results for the Latrobe River taken for the first round of monitoring in spring. No additional field notes were made during monitoring. Table 7 Latrobe River Catchment Round 1 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 226209B Moe River @ Darnum (Site 1) 23/09/2015 128.2 340.2 Overcast Moe Drain Site 2 (Start of Drain) 23/09/2015 150.9 374.5 Overcast Moe Drain Site 3 23/09/2015 231.4 447.1 Overcast 226402A Moe Drain @ Trafalgar (Site 4) 23/09/2015 234.7 493.2 Overcast Day 2 Moe River U/S Latrobe River (Site 5) 24/09/2015 240.5 488.6 Overcast 226204A Latrobe River @ Willowgrove 24/09/2015 437.9 92 Overcast Latrobe River U/S Moe Drain 24/09/2015 482.9 118.5 Overcast Latrobe River U/S Lake Narracan 24/09/2015 1338.7 191.1 Overcast (Becks Bridge) 226216A Tanjil River @ Tanjil South 24/09/2015 496.7 81 Overcast Tanjil River U/S Latrobe River 24/09/2015 483.1 98.5 Overcast 226218A Narracan Creek @ Thorpdale 24/09/2015 65.9 124 Overcast 226021A Narracan Creek @ Moe 24/09/2015 88.8 219.2 Overcast

Table 8 summarises the field results for the Latrobe River taken for the second round of monitoring in spring. The following field notes were obtained when sampling:

1. Tanjil River rising/falling quickly due to unsteady outflows from Blue Rock; and

2. Estimated flows 10 -15 ML/d entering Moe Drain just upstream of site 226402A Moe Drain at Trafalgar East from small drain.

18 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Table 8 Latrobe River Catchment Round 2 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 226209B Moe River @ Darnum (Site 1) 4/02/2016 14.7 359 Fine Moe Drain Site 2 (Start of Drain) 4/02/2016 13.8 340 Fine Moe Drain Site 3 4/02/2016 31.3 472 Fine 226402A Moe Drain @ Trafalgar (Site 4) 4/02/2016 38.6 570 Flows entering drain just upstream Moe River U/S Latrobe River (Site 5) 4/02/2016 38.8 547 Fine Day 2 Moe River U/S Latrobe River (Site 5) 5/02/2016 35.4 576 Fine 226204A Latrobe River @ Willowgrove 5/02/2016 227.5 98 Fine Latrobe River U/S Moe Drain 5/02/2016 276.6 111 Fine Latrobe River U/S Lake Narracan 5/02/2016 408.5 158 Fine (Becks Bridge) 226216A Tanjil River @ Tanjil South 5/02/2016 111.9 88 Fine Tanjil River U/S Latrobe River 5/02/2016 89.3 98 Fine 226218A Narracan Creek @ Thorpdale 5/02/2016 13.0 158 Fine 226021A Narracan Creek @ Moe 5/02/2016 17.8 283 Fine

Table 9 summarises the field results for the Latrobe River taken for the third round of monitoring in spring. The following field notes were obtained when sampling:

1. 226216A: Pumping from gauge pool at time of measurement, stage rising from 1.061 - 1.097 (m); and 2. Flow from Blue Rock dam increased during measurement.

Table 10 and Table 11 summarise additional water quality samples obtained at Moe Drain Site 3 and Site 4 to improve understanding of the relatively large gains in EC for modest gains in flow along this interstation reach. The results indicated that:

 Conductivity measured in situ was confirmed by the laboratory analysis;

 Water at both the Moe Site 3 and Trafalgar East sites are principally composed of sodium chloride hydrochemical facies;

 Nitrates and potassium concentrations increase downstream, potentially sourced from agricultural runoff identified increases are not of significant magnitude to account for the high rate of increase in electrical conductivity;

 It is possible that this reach receives baseflow from a more saline groundwater system at lower rates and that groundwater bores sampled and analysed to determine the groundwater end member EC do not monitor the same, or a connected, groundwater system;

 It is also possible that the flow measured is overestimated at the upstream site and/or underestimated at the downstream site. This would result in a lower reach inflow giving the impression of unusually high EC gains relative to the flow gain. The measurement error is likely to be less than 5%; therefore, while this may partially explain the observed phenomenon it would still indicate that groundwater discharge to the stream has a higher EC than expected.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 19 Table 9 Latrobe River Catchment Round 3 Field Results

Site Date Streamflow EC Comments (ML/d) (uS/cm) Day 1 226209B Moe River @ Darnum (Site 1) 16/05/2016 21.6 412 Windy / Overcast Moe Drain Site 2 (Start of Drain) 16/05/2016 26.0 396 Windy / Overcast Moe Drain Site 3 16/05/2016 38.4 484 Windy / Overcast 226402A Moe Drain @ Trafalgar (Site 4) 16/05/2016 48.8 577 Inflow upstream Est' 2-5ML/D Moe River U/S Latrobe River (Site 5) 16/05/2016 44.9 574 Windy / Overcast Day 2 Moe River U/S Latrobe River (Site 5) 17/05/2016 43.0 573 Windy / Overcast 226204A Latrobe River @ Willowgrove 17/05/2016 161.2 99 Windy / Overcast Latrobe River U/S Moe Drain 17/05/2016 173.8 136 Windy / Overcast Latrobe River U/S Lake Narracan 17/05/2016 365.0 195 Windy / Overcast (Becks Bridge) 226216A Tanjil River @ Tanjil South 17/05/2016 109.9 81 Windy / Overcast Tanjil River U/S Latrobe River 17/05/2016 107.7 103 Windy / Overcast 226218A Narracan Creek @ Thorpdale 17/05/2016 39.5 135 Windy / Overcast 226021A Narracan Creek @ Moe 17/05/2016 43.8 225 Windy / Overcast

Table 10 Moe Drain Site 3– Water Quality Results (Round 3 only)

Constituent Concentration Sample Date Alkalinity as Calcium Carbonate 31 mg/L 16/05/2016 Bicarbonate 38 mg/L 16/05/2016 Carbonate 0 mg/L 16/05/2016 Hydroxide 0 mg/L 16/05/2016 Ammonia as N 0.036 mg/L 16/05/2016 Calcium 11.1 mg/L 16/05/2016 Chloride 114 mg/L 16/05/2016 Conductivity 482 µScm 16/05/2016 Total Dissolved Solids (by EC) 260 mg/L 16/05/2016 Fluoride 0.1 mg/L 16/05/2016 Potassium 4.62 mg/L 16/05/2016 Magnesium 10.7 mg/L 16/05/2016 Sodium 57.3 mg/L 16/05/2016 Nitrite as Nitrogen 0.006 mg/L 16/05/2016 Nitrate + Nitrite as N 0.907 mg/L 16/05/2016 pH 7.1 pH units 16/05/2016 Silica - Reactive 11 mg/L 16/05/2016 Sulphate 13.2 mg/L 16/05/2016

20 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Table 11 226402A Moe Drain @ Trafalgar (Site 4) – Water Quality Results (Round 3 only)

Constituent Concentration Sample Date Alkalinity as Calcium Carbonate 28 mg/L 16/05/2016 Bicarbonate 34 mg/L 16/05/2016 Carbonate 0 mg/L 16/05/2016 Hydroxide 0 mg/L 16/05/2016 Ammonia as N 0.035 mg/L 16/05/2016 Calcium 10.7 mg/L 16/05/2016 Chloride 138 mg/L 16/05/2016 Conductivity 573 µScm 16/05/2016 Total Dissolved Solids (by EC) 310 mg/L 16/05/2016 Fluoride <0.1 mg/L 16/05/2016 Potassium 5.09 mg/L 16/05/2016 Magnesium 12.1 mg/L 16/05/2016 Sodium 73.6 mg/L 16/05/2016 Nitrite as Nitrogen 0.005 mg/L 16/05/2016 Nitrate + Nitrite as N 1.06 mg/L 16/05/2016 pH 7.1 pH units 16/05/2016 Silica - Reactive 11 mg/L 16/05/2016 Sulphate 13.5 mg/L 16/05/2016

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 21 400,000 410,000 420,000 430,000 440,000 450,000 BLUE ROCK BLUE MOONDARRA LAKE ROCK RESERVOIR TY R ER LAKE IV S # ER 0# 226216A Tanjil River @ Tanjil South 0# # Date: 24/09/2015 Flow: 496.7ML/d EC: 81 uS/cm Tanjil River U/S Latrobe River 226204A Latrobe River @ Willowgrove Date: 24/09/2015 Date: 24/09/2015 Flow: 483.1ML/d Flow: 437.9ML/d Latrobe River U/S Moe Drain EC: 98.5 uS/cm

5,780,000 EC: 92 uS/cm Date: 24/09/2015 5,780,000

TA Latrobe River U/S Lake Narracan (Becks Bridge) R # Flow: 482.9ML/d N IVE J Date: 24/09/2015

R I EC: 118.5 uS/cm # 0# L Flow: 1338.7ML/d EC: 191.1 uS/cm

# LAKE 226402A Moe Drain @ Trafalgar (Site 4) 0# NARRACAN Date: 23/09/2015 0# Flow: 234.7ML/d 0## LA TROB E

EC: 493.2 uS/cm # IVER # 0# R 0# MOE DRAIN 226021A Narracan Creek @ Moe 0## Date: 24/09/2015 ES AD MO 0# Flow: 88.8ML/d W K E # EE E CR RIVER EC: 219.2 uS/cm OL H K R EE E R T C EAR Moe River U/S Latrobe River (Site 5) A # W B EK 0 RE # Date: 24/09/2015 C Moe Drain Site 3 Flow: 240.5ML/d 5,770,000 Date: 23/09/2015 EC: 488.6 uS/cm 5,770,000 Flow: 231.4ML/d 226209B Moe River @ Darnum (Site 1) EC: 447.1 uS/cm L Moe Drain Site 2 (Start of Drain) L R Date: 23/09/2015 E E Date: 23/09/2015 W IV Flow: 128.2ML/d R R Flow: 150.9ML/d O EC: 340.2 uS/cm M EC: 374.5 uS/cm 226218A Narracan Creek @ Thorpdale AR BE Date: 24/09/2015 REEK CAN C RRA Flow: 65.9ML/d NA EK CRE EC: 124 uS/cm

0# #

BLUE ROCK BLUE MOONDARRA LAKE ROCK RESERVOIR TY R E 226204A Latrobe River @ Willowgrove LAKE IV RS # E Date: 5/02/2016 226216A Tanjil River @ Tanjil South R Flow: 227.5ML/d 0# Date: 5/02/2016 EC: 98 uS/cm # # Flow: 111.9ML/d 0 EC: 88 uS/cm Latrobe River U/S Moe Drain Date: 5/02/2016 Tanjil River U/S Latrobe River Flow: 276.6ML/d Date: 5/02/2016

EC: 111 uS/cm Flow: 89.3ML/d

EC: 98 uS/cm #

5,780,000 Moe River U/S Latrobe River (Site 5) 5,780,000 R TA

Date: 4/02/2016 IVE N # R J Flow: 38.8ML/d 0# IL

EC: 547 uS/cm 0# LAKE Moe River U/S Latrobe River (Site 5) # NARRACAN Date: 5/02/2016 0# # # ROB Flow: 35.4ML/d 0 LA T E EC: 576 uS/cm 0# RIVER 0# # MOE DRAIN # Latrobe River U/S Lake Narracan (Becks Bridge) #0# ES AD MO 0# Date: 5/02/2016 W EK E # RE RIVER Flow: 408.5ML/d C EC: 158 uS/cm 226209B Moe River @ Darnum (Site 1) # Date: 4/02/2016 Moe Drain Site 3 0# 226402A Moe Drain @ Trafalgar (Site 4) 226021A Narracan Creek @ Moe Flow: 14.7ML/d Date: 4/02/2016 Date: 4/02/2016 Date: 5/02/2016 EC: 359 uS/cm Flow: 31.3ML/d 5,770,000 Flow: 38.6ML/d Flow: 17.8ML/d 5,770,000 R EC: 472 uS/cm EC: 283 uS/cm EA K EC: 570 uS/cm B EE Moe Drain Site 2 (Start of Drain) CR Date: 4/02/2016 Flow: 13.8ML/d W A EC: 340 uS/cm T 226218A Narracan Creek @ Thorpdale E R Date: 5/02/2016 H AR O BE Flow: 13ML/d L REEK AN E C RAC EC: 158 uS/cm NAR C RE EK EK RE L C L

E #

W R # R 0 E O V M I R

BLUE ROCK BLUE MOONDARRA LAKE ROCK RESERVOIR TY Site Date Streamflow EC Comments R ER 226204A Latrobe River @ Willowgrove LAKE IV S (ML/d) (uS/cm) # E Date: 17/05/2016 226216A Tanjil River @ Tanjil South R Day 1 Flow: 161.2 ML/d #0 Date: 17/05/2016 226209B Moe River @ Darnum (Site 1) 16/05/2016 21.6 412 Windy / Overcast EC: 99 uS/cm #0 # Flow: 109.9 ML/d Moe Drain Site 2 (Start of Drain) 16/05/2016 26.0 396 Windy / Overcast EC: 81 uS/cm Moe Drain Site 3 16/05/2016 38.4 484 Windy / Overcast Latrobe River U/S Moe Drain Tanjil River U/S Latrobe River 226402A Moe Drain @ Trafalgar (Site 4) 16/05/2016 48.8 577 Inflow upstream Date: 17/05/2016 Date: 17/05/2016 Est' 2-5ML/D Flow: 173.8 ML/d Flow: 107.7 ML/d Moe River U/S Latrobe River (Site 5) 16/05/2016 44.9 574 Windy / Overcast EC: 136 uS/cm EC: 103 uS/cm

5,780,000 5,780,000 Day 2 # Moe River U/S Latrobe River (Site 5) Moe River U/S Latrobe River (Site 5) 17/05/2016 43.0 573 Windy / Overcast R TA

Date: 16/05/2016 IVE N # R J 226204A Latrobe River @ Willowgrove 17/05/2016 161.2 99 Windy / Overcast Flow: 44.9 ML/d #0 IL

Latrobe River U/S Moe Drain 17/05/2016 173.8 136 Windy / Overcast EC: 574 uS/cm # 0 LAKE Latrobe River U/S Lake Narracan 17/05/2016 365.0 195 Windy / Overcast Moe River U/S Latrobe River (Site 5) # #0NARRACAN (Becks Bridge) Date: 17/05/2016 #0 # TROB 226216A Tanjil River @ Tanjil South 17/05/2016 109.9 81 Windy / Overcast Flow: 43.0 ML/d LA E #0 RIVER Tanjil River U/S Latrobe River 17/05/2016 107.7 103 Windy / Overcast EC: 573 uS/cm # 226218A Narracan Creek @ Thorpdale 17/05/2016 39.5 135 Windy / Overcast #0 226021A Narracan Creek @ Moe 17/05/2016 43.8 225 Windy / Overcast MOE DRAIN # Latrobe River U/S Lake Narracan (Becks Bridge) S # #0 DE #0 Date: 17/05/2016 WA K MOE # EE Flow: 365.0 ML/d E CR 226209B Moe River @ Darnum (Site 1) RIVER OL EC: 195 uS/cm H EK

Date: 16/05/2016 # R E E R Flow: 21.6 ML/d T C #0 Moe Drain Site 3 A EC: 412 uS/cm 226402A Moe Drain @ Trafalgar (Site 4) 226021A Narracan Creek @ Moe W Date: 16/05/2016 Date: 17/05/2016 Flow: 38.4 ML/d Date: 16/05/2016 5,770,000 5,770,000 Flow: 48.8 ML/d Flow: 43.8 ML/d R EC: 484 uS/cm EC: 225 uS/cm EA K EC: 577 uS/cm B EE R Moe Drain Site 2 (Start of Drain) L C L R Date: 16/05/2016 E E W IV Flow: 26.0 ML/d R R EC: 396 uS/cm O M 226218A Narracan Creek @ Thorpdale AR BE Date: 17/05/2016 REEK CAN C RRA Flow: 39.5 ML/d NA EK EC: 135 uS/cm CRE

#0 #

400,000 410,000 420,000 430,000 440,000 450,000 0# Field Sampling Location Stream Latrobe River Catchment Major Water Area Channel River Drain/Channel/Other

Job Number 31-32709 Paper Size A3 Department of Environment, Land, Water and Planning A 0 1,0002,000 4,000 6,000 8,000 Gippsland Rivers Baseflow Assessment Revision Date 19 May 2016 Metres Map Projection: Transverse Mercator Field Monitoring Results Horizontal Datum: GDA 1994 Grid: GDA 1994 MGA Zone 55 o Latrobe River Figure 7 G:\31\32709\GIS\Maps\Deliverables\FieldResults\3132709_KBM_A3P_Stage2_FieldResults_Latrobe.mxd Hazelwood Drive (cnr Lignite Court) Morwell VIC 3840 Australia T 61 3 5136 5800 F 61 3 5136 5888 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by:adrummond 4. Revised Baseflow Estimates

4.1 Introduction

Downstream flow and EC ‘accretion profiles’ were prepared based on the field observations (Section 3) to show the changes in streamflow conditions along each river. These flow and EC accretion profiles can be used to infer baseflow contributions to the stream, with baseflow gains likely when EC is increasing between upstream and downstream sampling sites (i.e. within an ‘interstation reach’).

To further quantify the magnitude of baseflow gains, reach-scale mass balances were constructed using the field data, in the same manner as was applied by GHD (2015) using historical gauge data. As outlined by GHD (2015), the equation for this reach-scale EC mass balance for estimating baseflow fluxes to a given reach is:

( − ) = Where: is the groundwater-derived (baseflow)( −component) of stream flow from within the reach only, excluding baseflow inputs from further upstream; is the average stream flow across the reach (i.e. of upstream and downstream gauged flows); is the tracer concentration in the stream at the downstream end of the reach, is the tracer concentration in the stream at the upstream end, is the groundwater (baseflow) end member tracer concentration within the area thought to be contributing baseflow to the reach. Refer to Stage 1 of this study for further details on the reach-scale mass balance method (GHD, 2015).

In some reaches, there are other factors that complicate the analysis. These include:  Water storages within the reach that are not in equilibrium (inflow and outflow not equal), or that are of a size such that the full mixing of the flow does not occur. Examples of this include: – Maffra Weir; and – Possibly Cowwarr Weir.  Reaches with offtakes or inflows that are somewhat uncertain. Examples include: – Cowwarr Weir offtake (based on SRW operator comments); – Maffra Weir offtake (based on SRW operator comments); and – Thomson Syphon outfall (estimated in the field).  Solute concentration through evapotranspiration along an interstation reach, which is a highly uncertain process. While in many cases the inferred baseflow gains are an order of magnitude greater than the likely effect (e.g. Macalister River), in other cases, depending on the assumptions adopted, evapotranspiration may be a reasonable explanation for the EC increases observed (e.g. some reaches of the Thomson River in summer).

 Other mechanisms that can affect EC. A very large EC increase was consistently observed in the Moe Drain reach upstream of Trafalgar East. This gain is difficult to explain solely as baseflow gains, as it would require a very saline groundwater contribution. It is therefore recommended that major ions and nutrients be analysed on this reach to identify other possible causes for the increases in EC (e.g. agricultural or urban runoff).

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 23 4.2 Thomson River Figure 8 presents the stream flow and EC accretion profiles for the Thomson River for all field sampling rounds. Annotations are provided to outline our interpretation of the data. Results for the Thomson River indicate that baseflow conditions (i.e. gain from or loss to groundwater) are variable along its length and between seasons. In spring, the data suggest:

 Neutral or losing baseflow conditions between US Cowwarr and DS Cowwarr, and between Stoney Creek and Back Creek  Rainbow Creek probably gains baseflow along its length, and

 Baseflow-gaining conditions along the remaining Thomson River reaches. The gains towards Wandocka may be indicative of irrigation returns from shallow groundwater drains.

In summer, the data suggest:

 Gaining baseflow conditions upstream of Cowwarr Weir  Neutral to mildly gaining between Cowwarr Weir and Stoney Creek;

 Uncertainty in evapotranspiration effects on observed minor EC gains downstream of Stony Creek and along Rainbow Creek. No firm conclusions can be made for these reaches in this sampling round. At best, the minor EC gains suggest minimal, if any, baseflow gains in summer along these lower reaches.

In autumn, the data suggest:

 Neutral or losing baseflow conditions between Cowwarr Weir and Timber Weir

 Likely baseflow gains along Rainbow Creek

 Neutral to mildly gaining baseflow conditions between Cowwarr Weir and Back Creek

 Significant uncertainty in evapotranspiration effects on mild EC gains downstream of Back Creek, where no firm conclusion can be made in this sampling round, and very mild EC gains suggest these reaches are most likely neutral.

Across seasons, the only consistent areas of baseflow gain appear to be:

 Downstream of Cowwarr Weir, particularly during high river stage behind the weir. The consistent baseflow gains immediately downstream of the weir are likely due to the artificial maintenance of high upstream surface water levels behind the weir, with the downward grade in the river bed and stage immediately downstream of the weir effectively forming a drain towards which groundwater from beneath the weir is driven  Along Rainbow Creek, which is more deeply incised into the landscape than the main channel of the Thomson River (see the topographic profile at the bottom of Figure 8), noting however that no firm conclusion could be made for the summer (January 2016) sampling round. Rainbow Creek probably forms a natural drain towards which groundwater from beneath the more elevated Thomson River will flow.

These observations are in broad agreement with the earlier work of GHD (2015). The identified neutral or losing reaches provide confirmation of anecdotal evidence of losses in the reaches of the lower Thomson towards/upstream of Cowwarr Weir (Terry Flynn (SRW), pers. Comm., 2015). The field data presented here provide significantly greater spatial resolution of baseflow gains and losses than the earlier work of GHD (2015), which only used data from the available permanent gauging stations. The detailed analysis presented here has also allowed for more thorough investigation of the effects of offtakes and evapotranspiration.

24 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Thomson River - Sampling Round 1 - September 2015 150 8 Thomson River - Sampling Round 1 - September 2015 1600

500 140 Likely Likely Likely neutral or Likely gaining reach Likely 7 Moderate to high gain of relatively fresh 1400 neutral gaining losing reach on on Thomson and gaining flows in the two upstream reaches, but Flow Gain EC of flow gain 130 Rainbow or reach Thomson, gaining Rainbow Ck reach Wandocka 6 small baseflow gain; flow increases US streamflow EC GW EC Thomson DS Thomson Stony Ck Stony

Back Ck Back 1200 400 losing Cowwarr DS US Cowwarr US Thomson DS Thomson on Rainbow Ck mainly from inflows from minor Thomson US Thomson 120 reach ≈67 ML ≈15 ML syphon inflow 5 triburaries.. BFI:6% 1000 offtake ≈67 ML re- 110 Relatively consistent flow gains along Rainbow Creek, and Thomson downstream of enters from 4 Rainbow Creek with relatively consistent EC, indicating similar rates of baseflow gain. 300 BFI:1% ≈57 ML Rainbow Ck 100 Larger EC gain along Rainbow Ck, probably because it is more deeply incised (see 800 diversion into 3 topo profile below). I.e. greater chance of creek bed intersecting the watertable).

Flow (ML/d) Flow 90 200 Rainbow Ck Flow gain between US Back Creek 600 2 80 and Rainbow Creek.

Flow Gain/Loss (ML/d/km)Gain/Loss Flow BFI:15% BFI:13% 400 Neutral to slight EC gains along the Thomson River upstream of Back (uS/cm) Conductivity Electrical 1

Rainbow Ck BFI:28% uS/cm)(EC; Conductivity Electrical 100 70 Creek. Upstream of Cowarr, and between Stony Creek and Back Creek, Rainbow Ck re-enters EC increases are consistent with evaporation effects, so these reaches 200 Rainbow Ck Thomson Flow (ML/d) 60 0 Flow Loss EC Gain are probably neutral or losing. Relatively low EC between US Back Creek and Rainbow diversion Flow loss between DS Stony EC (uS/cm) Creek indicates a mix of baseflow and other flow. 0 EC gains downstream of Back Creek, and along Rainbow Creek. 50 -1 Creek and US Back Creek 0 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000

400 Thomson River - Sampling Round 2 - January 2016 150 8 Thomson River - Sampling Round 2 - January 2016 1600 Likely Likely No conclusion possible Likely neutral to gaining No conclusion possible gaining neutral to for Thomson River or reach on Thomson, Uncertain 140 350 Flow (ML/d) 1400 reach gaining Rainbow Ck on Rainbow Ck. 6 reach EC (uS/cm) 130 Flow Gain EC of flow gain 300 US streamflow EC GW EC 1200 120 4 Baseflow gains between

Rainbow Cowwarr and Stony Creek US Cowwarr US 250 DS Thomson Uncertain baseflow conditions downstream of Back Ck, where EC gains 1000 Wandocka

Back Ck Back 110 Stony Ck Stony BFI:19% could be partly or fully explained by evaporation depending on DS Cowwarr DS 2 Thomson US Thomson ≈21 ML DS Thomson assumptions in all other reaches. 200 ≈40 ML 100 800 offtake Flow Loss EC Gain ≈57 ML syphon inflow 0 Flow (ML/d) Flow 90 150 diversion ≈53 ML re- Flow Loss EC Gain 600 into enters from Rainbow Ck 80 -2 Flow Gain/Loss (ML/d/km)Gain/Loss Flow Flow Loss EC Gain 100 Rainbow Ck 400 EC gains downstream of Stony Creek and along Rainbow Creek could indicate baseflow gains, evaporation or (uS/cm) Conductivity Electrical Flow Loss EC Gain (uS/cm) Conductivity Electrical 70 Uncertain baseflow conditions between a combination of the two processes, due to uncertainty in the estimation of evaporation. Stony Creek and Back Creek. 50 -4 200 Rainbow Ck Diversion Rainbow Ck re-enters 60 Flow Loss EC Gain Thomson 0 50 -6 0 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000

250 Thomson River - Sampling Round 3 - April 2016 2 Thomson River - Sampling Round 3 - April 2016 1600 Likely Likely Likely neutral to gaining Uncertain on Thomson, Uncertain, likely neutral Baseflow gains between Moderate baseflow gains neutral neutral to reach Strongly gaining on Rainbow 100 along Rainbow Creek 1.5 Cowwarr and Stony Creek 1400 or losing gaining Ck. Rainbow Flow Gain EC of Flow Gain reach reach Wandocka 200 DS Thomson 1 Upstream Flow EC GW EC 1200 90 US Cowwarr US

DS Cowwarr DS ≈35 ML

Back Ck Back syphon inflow Stony Ck Stony 0.5 BFI:10% 1000 Thomson US Thomson 150 DS Thomson BFI:17% 80 Flow Gain EC Drop ≈21 ML BFI:61% offtake 0 800 Uncertain baseflow conditions Flow Loss EC Gain

Flow (ML/d) Flow 100 downstream of Rainbow Creek, where EC ≈51 ML re- -0.5 600 ≈48 ML 70 drops are may be explained by enters from diversion incomplete mixing of fresh Siphon Rainbow Ck (ML/d/km)Gain/Loss Flow -1 400 into Flow (ML/d) (uS/cm) Conductivity Electrical Flow Loss EC Static Uncertain baseflow conditions inflows at the site downstream of (uS/cm) Conductivity Electrical 50 Rainbow Ck Rainbow Creek, or other irrigation Rainbow Ck re-enters EC (uS/cm) 60 downstream of Back Ck, where EC gain Rainbow Ck Diversion returns Thomson -1.5 may be explained by evaporation. 200 EC gains downstream of Stony Creek could indicate baseflow gains, evaporation or a combination of the two processes, due to uncertainty in the estimation of evaporation. Rainbow Creek is however likely stringly gaining baseflow. 0 50 -2 0 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000

80 -2993 2007 7007 12007 17007 22007 80 80 -2993 2007 7007 12007 17007 22007 80 Thomson River Thomson River 70 70 70 70 60 Rainbow Creek 60 60 Rainbow Creek 60 Cowwarr 50 50 50 50 Weir 40 40 40 40 (mAHD) (mAHD) 30 30 30 30 20 20 20 20 Land Surface Elevation SurfaceLand Rainbow Creek has been plotted along the equivalent Thomson River chainage, Rainbow Creek is approximately 12 km shorter. Elevation SurfaceLand Rainbow Creek has been plotted along the equivalent Thomson River chainage, Rainbow Creek is approximately 12 km shorter. 10 10 10 10 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 Thomson River Chainage (m) Thomson River Chainage (m)

Figure 8 Flow and EC accretion profiles - Thomson River Catchment 455,000 460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000

M THO SO Thomson River U/S Cowwarr Weir N RIVE R Int Baseflow: 33.9 ML/d Spring Field Monitoring Round 1 (09/09/2015 - 10/09/2015) Likely gaining reach Thomson River D/S Stoney Ck # Int Baseflow: 0.3 ML/d Thomson River U/S of Rainbow Ck Interpretation of field observations from the spring monitoring round suggest: Likely gaining reach Int Baseflow: 0.6 ML/d - Neutral or losing baseflow conditions between Stoney Creek and Back Creek. Thomson River U/S Back Ck Likely gaining reach #0 Int Baseflow: 0.1 ML/d - Likely baseflow gains along Rainbow Creek.

Likely neutral / losing reach

# - Baseflow - gaining conditions along the remaining Thomson River reaches. The # gains towards Wandocka may be indicative of irrigation returns from shallow

#0 # groundwater drains. #

Thomson River D/S Cowwarr Weir # 5,795,000 #0 Thomson River To Wandocka 5,795,000 Int Baseflow: 0.2 ML/d #0 Int Baseflow: 2.0 ML/d Likely gaining reach #0 Likely gaining reach #0#0 R

#0 E RAINBO EK # E V W CR I

R # R

#0 E

T S Rainbow Ck U/S of Thomson I

Int Baseflow: 4.7 ML/d A

Likely gaining reach A

455,000 460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000 455,000 460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000

Summer Field Monitoring Round 2 (12/01/2016 - 13/01/2016) Thomson River U/S Cowwarr Weir Thomson River D/S Stoney Ck Int Baseflow: 29.8 ML/d Int Baseflow: 0.3 ML/d Likely gaining reach Likely neutral to gaining reach Interpretation of field observations from the summer monitoring round suggest:

# Thomson River U/S of Rainbow Ck - Gaining baseflow conditions upstream of Cowwarr Weir. Int Baseflow: 0.3 ML/d Likely neutral to gaining reach - Neutral to mildly gaining between Cowwarr Weir and Stoney Creek. #0 Thomson River U/S Back Ck - Exceedingly significant uncertainty in evapotranspiration effects on observed mild

# No conclusion possible EC gains downstream of Stoney Creek and along Rainbow Creek. No firm #0 # Thomson River To Wandocka conclusion can be made from these reaches in this sampling round. At best, the mild T EC gains suggest very minimal, if any, baseflow gains in summer along these lower reaches. H No conclusion possible

# O # *EC gains could potentially be Thomson River D/S Cowwarr Weir M 5,795,000 S R #0 attributed to evaporation. 5,795,000 Int Baseflow: 7.0 ML/d ON RIVE #0 Likely gaining reach

#0 #0#0 R

#0 E RAINBO K # EE V W CR I R

# R

#0 E T

S I

Rainbow Ck U/S of Thomson A

No conclusion possible A

455,000 460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000

THOMSO Thomson River U/S Cowwarr Weir N RIVE R Int Baseflow: 11.6 ML/d Autumn Field Monitoring Round 3 (12/04/2016 - 13/04/2016) Likely gaining reach Thomson River D/S Stoney Ck

# Int Baseflow: 0.03 ML/d Interpretation of field observations from the autumn monitoring round suggest: Likely gaining / neutral reach Thomson River U/S Back Ck - Likely baseflow gains along Rainbow Creek.

#0 Int Baseflow: 0.1 ML/d Thomson River U/S of Rainbow Ck - Neutral to mildly gaining baseflow conditions between Cowwarr Weir and Back Creek. # Likely gaining / neutral reach No conclusion possible - Exceedingly significant uncertainty in evapotranspiration effects on mild EC gains

downstream of Back Creek, where no firm conclusion can be made from these reaches

# #0 #

in this sampling round, and very mild EC gains suggest these reaches are most likely neutral. # 5,795,000 5,795,000 #0 # Across seasons, the only consistent areas of baseflow gain appear to be: #0 Thomson River To Wandocka No conclusion possible 1. Downstream of Cowwarr Weir, particularly during high flows into and out of the weir. #0 #0#0#0

RAINBO EEK # The consistent baseflow gains immediately downstream of the weir are likely due to the artificial W CR maintenance of high surface water levels upstream (behind the weir); the downward topographic # #0 shift in the river bed and stage immediately downstream of the weir effectively forms a drain Thomson River D/S Cowwarr Weir towards which groundwater from beneath the weir is driven. Int Baseflow: 0.0 ML/d Likely gaining / neutral reach 2. Along Rainbow Creek, which is more deeply incised into the landscape than the main channel Rainbow Ck U/S of Thomson of the Thomson River (see the topographic profile at the bottom of Figure 8). It is however noted Int Baseflow: 2.7 ML/d that no firm conclusion could be made for the summer (January 2016) sampling round. Likely gaining reach Rainbow Creek probably forms a natural drain towards which groundwater from beneath the more elevated Thomson River will flow. 455,000 460,000 465,000 470,000 475,000 480,000 485,000 490,000 495,000 500,000

Field Sampling River Losing / Neutral Department of Environment Land Water and Planning Job Number 31-32709 Paper Size A3 Baseflow #0 Location Revision A 0 0.5 1 2 3 4 Stream Classification Unclassified Gippsland Rivers Baseflow Assessment Thomson Macalister Date 19 May 2016 Channel Gaining Kilometers River Catchment

Map Projection: Transverse Mercator Drain/Channel/Ot... Gaining / Neutral Baseflow Interstation Analysis Horizontal Datum: GDA 1994 o Major Water Area Neutral Grid: GDA 1994 MGA Zone 55 Thomson River Figure 9 G:\31\32709\GIS\Maps\Deliverables\3132709_KBM_A3L_Stage2_IntResults_Thomson.mxd 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by:adrummond 4.3 Macalister River

Figure 10 presents the stream flow and EC accretion profiles for the Macalister River for all field sampling rounds. Annotations are provided to outline our interpretation of the data. Figure 11 presents the inferences made regarding baseflow conditions along the Macalister River in map form to aid in interpretation. Results for the Macalister River indicate that the baseflow- conditions (i.e. gain from or loss to groundwater) vary along its length and between seasons.

In spring, the data suggest:

 Gaining baseflow conditions between D/S Glenmaggie through U/S Newry Drain, and to U/S Maffra Weir

 Gaining baseflow conditions D/S of Maffra Weir to Riverslea, and

 No conclusion can be made regarding baseflow conditions between U/S Maffra Weir and D/S Maffra Weir. This is due to the effect of storage and mixing (of stream EC) within the weir pool and disequilibrium between inflows to the weir and outflows from the weir on the day of sampling. Despite this uncertainty, this reach is likely to be either losing or neutral with regard to baseflow, given that water in the weir pool is artificially maintained at elevations above the watertable (refer to the DEM elevation profile in Figure 10).

In summer, the data suggest:

 Neutral or losing baseflow conditions between D/S Glenmaggie through U/S Newry Drain. This reach has switched from gaining to neutral or losing conditions in spring

 Gaining baseflow conditions D/S of Maffra Weir to Riverslea, exhibiting similar baseflow conditions as observed in spring, and

 No conclusion can be made regarding baseflow conditions between U/S Maffra Weir and D/S Maffra Weir for the same reasons as outlined for the spring data set. However, in summer, inferences for this reach become more uncertain as the potential effect of ET increases.

In autumn, the data suggest:

 Uncertain conditions between Glenmaggie and US Newry Drain, with flow loss and gaining EC, indicating that ET from the stream and riparian zone may be of significance;

 Gaining baseflow conditions between U/S Newry Drain and U/S Maffra Weir, and D/S of Maffra Weir to Riverslea, similar to the spring and summer round; and

 No conclusion can be made regarding the baseflow conditions between U/S Maffra Weir and D/S Maffra Weir for the same reasons as outlined in the spring. The only reaches exhibiting seasonally-consistent baseflow conditions are between US Newry Drain and US Maffra Weir, and DS Maffra Weir to Riverslea, where gains were observed across all sampling events. The seasonal neutral to losing behaviour concluded for the upstream reach (between DS Glenmaggie and US Newry Drain) make sense conceptually due to the relatively elevated river bed, when compared to downstream reaches (see lower chart in Figure 10). The elevated river bed in conjunction with high river flows (releases from Glenmaggie Weir in Summer (January 2016)) create hydraulically losing conditions in this reach. Losing behaviour in basin margin reaches was also noted in earlier studies by GHD (2013a).

The observations are in broad agreement with the earlier work of GHD (2015), although there are some significant but unresolvable differences, as detailed in Section 5.1. The broad picture of neutral to losing conditions downstream of Glenmaggie Weir, and generally gaining conditions downstream of Newry Drain (aside from around Maffra Weir) is consistent with the earlier work, noting that there are temporal differences.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 27 Macalister River - Sampling Round 1 - September 2015 4 Macalister River - Sampling Round 1 - September 2015 500 No conclusion Flow Gain 450 200 Likely gaining reach Likely gaining reach possible for Likely gaining reach 200 3.5 Moderate baseflow gains from US Newry Drain to Riverslea except in the reach that Maffra Weir EC of Flow Gain 400 Weir contains Maffra weir ; this weir-affected reach cannot be analysed due to the weir pool reach Weir DS Maffra DS 3 not reaching equilibrium between inflow to and outflow from the weir pool.

US Maffra US 350 150 Riverslea 150 2.5 300 US Newry Drain Newry US ≈60 ML BFI:22% offtake DS Glenmaggie DS 2 BFI:21% 250 100 100

Flow (ML/d) Flow 200 1.5 150

Flow Gain/Loss (ML/d/km)Gain/Loss Flow BFI:0% 1 Electrical Conductivity (uS/cm) Conductivity Electrical Despite the above comments, given that water in (uS/cm) Conductivity Electrical 50 50 100 BFI:11% the weir pool is artificially maintained above the Steady flow gains along all reaches (after accounting for offtakes from Maffra Weir) Flow (ML/d) 0.5 Low flow gains with low BFI between Lake watertable (see DEM elevation profile below), this EC increases indicative of baseflow gains on all reaches except across the weir pool; 50 EC (uS/cm) Glenmaggie and US of Newry Drain. reach is likely to be either losing or neutral with this reach shows an EC loss which is likely explained by mixing in the weir pool. 0 0 0 regard to baseflow. 0 0 10000 20000 30000 40000 50000 60000 0 10000 20000 30000 40000 50000 60000

350 Macalister River - Sampling Round 2 - January 2016 8 Macalister River - Sampling Round 2 - January 2016 600 No conclusion possible for 200 Low to moderate flow gains of with moderate BFI between US of Newry 300 Neutral or losing reach Likely gaining reach Likely gaining reach 6 Drain and Maffra Weir, and between Maffra Weir and Riverslea. Weir Maffra Weir 500

US Maffra US reach DS Glenmaggie DS 4 250 Drain Newry US BFI:30% 150 400 Weir 2 DS Maffra DS BFI:35% 200 0 Flow Loss EC Drop 300 Neutral or losing conditions between 100 150 Riverslea

Flow (ML/d) Flow Glenmaggie and US Newry Drain with ≈107 ML -2 Neutral to losing conditions flow loss and EC static. offtake between Lake Glenmaggie and 200 100 Flow Gain/Loss (ML/d/km)Gain/Loss Flow US of Newry Drain. -4 Electrical Conductivity (uS/cm) Conductivity Electrical 50 (uS/cm) Conductivity Electrical Flow and EC gains indicating baseflow gains between US Newry Drain and Flow Gain/Loss 100 50 US Maffra Weir ,and between DS Maffra Weir and Riverslea. This Flow (ML/d) -6 isconsistent with loctation of know farm drain outfalls. EC (uS/cm) Flow Loss EC Gain EC of Flow Gain 0 0 -8 0 0 10000 20000 30000 40000 50000 60000 0 10000 20000 30000 40000 50000 60000

200 Macalister River - Sampling Round 3 - April 2016 8 Macalister River - Sampling Round 3 - April 2016 600 No conclusion Weir 200 Low to moderate flow gains of with moderate BFI between US of Newry Drain Riverslea. 180 possible for Maffra DS 6 Uncertain reach Likely gaining reach Weir Maffra Weir Likely gaining reach

US Maffra US 500 160 reach BFI:7% DS Glenmaggie DS 4

140 Drain Newry US ≈108 ML 150 2 BFI:12% BFI:24% 400 120 offtake 0 Flow Loss EC Gain 100 Unknown conditions between 300 100 Glenmaggie and US Newry Drain with -2 Riverslea Flow (ML/d) Flow 80 flow loss and EC gaining. Stream ET Unkown conditions between may be important. -4 Lake Glenmaggie and US of 200 60

Flow Gain/Loss (ML/d/km)Gain/Loss Flow Newry Drain. Stream ET may be EC of reach inflows is unexpectedly low, 50 (uS/cm) Conductivity Electrical -6 significant. especially given the Carter Creek a trib to this (uS/cm) Conductivity Electrical 40 Flow and EC gains indicating baseflow gains between US Newry Drain and reach had an EC of 560. Flow Gain/Loss 100 Series1 20 Riverslea. This is consistent with loctation of know farm drain outfalls. -8 Series2 EC of Flow Gain 0 0 -10 0 0 10000 20000 30000 40000 50000 60000 0 10000 20000 30000 40000 50000 60000

50 50 45 45 40 40 35 Maffra 35 Maffra 30 Weir 30 Weir

(mAHD) 25 (mAHD) 25 20 20

Land Surface Elevation SurfaceLand 15 Elevation SurfaceLand 15 10 10 0 10000 20000 30000 40000 50000 60000 0 10000 20000 30000 40000 50000 60000 Macalister River Chainage (m) Macalister River Chainage (m)

Figure 10 Flow and EC accretion profiles - Macalister River Catchment 485,000 490,000 495,000 500,000 485,000 490,000 495,000 500,000 485,000 490,000 495,000 500,000 5,810,000 5,810,000 5,810,000 5,810,000 5,810,000 5,810,000

Macalister River U/S of Glenmaggie Int Baseflow: 3.0 ML/d Macalister River U/S of Glenmaggie Gaining reach Macalister River U/S of Glenmaggie Int Baseflow: 0.8 ML/d *Regulated reach so flow Int Baseflow: 1.9 ML/d

Gaining reach and EC is higher in summer. Gaining reach

# # # Macalister River U/S Newry Drain #0 # #0 #0 Int Baseflow: 5.2 ML/d 5,805,000 5,805,000 5,805,000 5,805,000 Macalister River U/S Newry Drain 5,805,000 Macalister River U/S Newry Drain 5,805,000 No conclusion possible Int Baseflow: 6.7 ML/d Int Baseflow: 0 ML/d *Flow loss and EC gain could be Gaining reach Neutral to losing reach due to stream ET.

LAKE LAKE # LAKE #

GLENMAGGIE GLENMAGGIE # # GLENMAGGIE

M M M A A TER A A TER C IS R C L IS R A A TER L C L IS R I I V V I V

#0E #0 #0E

R #0 #0 R #0 #

# 5,800,000 5,800,000

5,800,000 5,800,000 # 5,800,000 5,800,000

# Macalister River U/S Maffra Weir # Macalister River U/S Maffraa Weir Macalister River U/S Maffra Weir # Int Baseflow: 6.4 ML/d Int Baseflow: 5.2 ML/d Int Baseflow: 2.1 ML/d Gaining reach Gaining reach Gaining reach Macalister River - Maffra Weir Pool #0 #0 Baseflow could not be analysed #0 due to storage of fresh water in the Macalister River - Maffra Weir Pool Macalister River - Maffra Weir Pool weir pool (not in equilibrium). Unclassified reach Unclassified reach

# # 5,795,000 5,795,000 5,795,000 5,795,000 5,795,000 5,795,000

# R R MS E R OMSO E HO O I V OMSO VE TH N I V T N R TH N RI R Macalister River U/S Riverslea Macalister River U/S Riverslea Macalister River U/S Riverslea Int Baseflow: 7.5 ML/d Int Baseflow: 11.8 ML/d Int Baseflow: 3.0 ML/d Gaining reach Gaining reach Gaining reach #0 #0 #0 5,790,000 5,790,000 5,790,000 5,790,000 5,790,000 5,790,000

Across seasons, the only consistent baseflow conditions appear to be: 5,785,000 5,785,000 5,785,000 5,785,000 5,785,000 5,785,000 1. Between US Newry Drain and US Maffra Weir, and DS Maffra Weir to Riverslea, where gains were observed across all sampling events. The seasonal neutral to losing behaviour concluded for the upstream reach (between DS Glenmaggie and US Newry Drain) makes conceptual sense because of the relatively elevated river bed, when compared to downstream reaches. The elevated river bed in conjunction with high river flows (releases from Glenmaggie Weir in Summer (January 2016)) poses hydraulically losing conditions from the river in this reach. Losing behaviour in basin margin reaches was also noted in earlier studies by GHD (2013a). Summer Field Monitoring Round 2 (14/01/2016)

Spring Field Monitoring Round 1 (28/09/2015) Intrpretations from field observation from the summer monitoring round suggest: Autumn Field Monitoring Round 3 (14/04/2016) 5,780,000 5,780,000

5,780,000 5,780,000 - Neutral or losing baseflow conditions between D/S Glenmaggie through to Interpretation of field observations from the spring monitoring ruond suggest: 5,780,000 U/S Newry Drain. This reach has switched from gaining to neutral / losing 5,780,000 Interpretations from field observation from the autumn monitoring round suggest: - Gaining baseflow conditions between D/S Glenmaggie through U/S Newry Drain conditions from spring to summer. - Unknown conditions between Glenmaggie and US Newry Drain, with flow loss and to U/S Maffra Weir; - Gaining baseflow conditions between U/S Newry Drain and U/S Maffra Weir and EC gain indicating that stream ET may be an issue. - Gaining baseflow conditions downstream fo Maffra Weir to Riverslea; and and downstream of Maffra Weir to Riverslea, similar to the spring round. - Gaining baseflow conditions between U/S Newry Drain and U/S Maffra Weir - No conclusion can be made regarding baseflow conditions between U/S - No conclusion can be made regarding the baseflow conditions between U/S and downstream of Maffra Weir to Riverslea, similar to the spring and summer round. Maffra Weir and D/S Maffra Weir. This is due to the effect of storage and Maffra Weir and D/S Maffra Weir for the same reasons as outlined in the spring - No conclusion can be made regarding the baseflow conditions between U/S

mixing (of stream EC) within the weir pool, and disequilibrium between inflows dataset. However, in summer,. inferences for this reach become more uncertain Maffra Weir and D/S Maffra Weir for the same reasons as outlined in the spring # # #

to the weir and outflows from the weir on the day of sampling. # as the potential effects of ET increases in summer. dataset. 5,775,000 5,775,000 5,775,000 5,775,000 485,000 490,000 495,000 500,000 5,775,000 485,000 490,000 495,000 500,000 5,775,000 485,000 490,000 495,000 500,000

Field Sampling Stream Losing / Neutral Department of Environment Land Water and Planning Job Number 31-32709 Paper Size A3 Baseflow #0 Location Revision A 0 0.5 1 2 3 4 Channel Classification Unclassified Gippsland Rivers Baseflow Assessment Thomson Macalister Date 19 May 2016 Drain/Channel/Ot... Gaining Kilometers River Catchment Gaining / Neutral Map Projection: Transverse Mercator Major Water Area Baseflow Interstation Analysis Horizontal Datum: GDA 1994 o Neutral Grid: GDA 1994 MGA Zone 55 River Macalister River Figure 11 G:\31\32709\GIS\Maps\Deliverables\3132709_KBM_A3P_Stage2_IntResults_Macalister.mxd 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by:adrummond 4.4 Latrobe River

Figure 12 presents the stream flow and EC accretion profiles for the Latrobe River for all field sampling rounds. Annotations are provided to outline our interpretation of the data. Figure 13 presents the inferences made regarding baseflow conditions along the Latrobe River in map form to aid in interpretation. The results for the Latrobe River indicate that baseflow conditions (i.e. gain from or loss to groundwater) are variable along its length and between seasons.

In spring, the data suggest:

 Gaining baseflow conditions along the length of the Latrobe River between Willowgrove and Lake Narracan, and

 Gaining baseflow conditions along the Moe River and Drain between Darnum and its confluence with the Latrobe River (upstream of Lake Narracan). However, this gaining condition is less clear in the Drain’s lowers reaches towards the confluence, where neutral to slightly gaining baseflow conditions are inferred.

In summer, the data suggest:  Gaining baseflow conditions along the length of the Latrobe River between Willowgrove and Lake Narracan, where there is no change from the inferred condition in spring, and

 Neutral baseflow conditions along much of then Moe River and Drain, with the exception of the sub-reach between Site No. 2 and Site No. 3, where gaining conditions are inferred. From spring to summer, the Moe River and Drain has become less baseflow dependent.

In autumn, the data suggests:

 Gaining baseflow conditions along the length of the Latrobe River between Willowgrove and upstream of Moe Drain, i.e. no change from the inferred conditions in spring and summer

 Neutral baseflow conditions along much of the Moe River and Drain, with the exception of the sub-reach between Site No. 2 and Site No. 3, where gaining conditions are inferred. From summer to autumn, the Moe River and Drain have become more baseflow dependent, and

 Inconclusive conditions in the Latrobe River downstream of the Moe Drain, where flow losses and gains in EC could partially be attributed to evaporation impacts.

Moderately gaining baseflow conditions are consistently experienced across seasons for the upper reaches of the Latrobe River, Tanjil River and Narracan Creek; however, baseflow gains are generally reduced in summer. The data suggests relatively variable seasonal baseflow conditions along the Moe Drain, with predominantly gaining conditions exhibited during spring and relatively neutral conditions during summer and autumn. Analysis of baseflow gains in these upper reaches of the Latrobe River was not possible using existing gauging station data, as outlined by GHD (2015). Therefore, the sub-reach scale baseflow estimates provided from this study are a significant expansion of our understanding of baseflow conditions in this area. Importantly, the data suggest that a significant proportion of groundwater with the Moe Basin aquifers probably discharges up into the Moe River and Drain, and into the Latrobe River, upstream of its continuation eastward into the Latrobe Valley. These inferences are in agreement with GHD (2010a) and Brumley and Holdgate (1983). Importantly, whilst the Moe Drain appears to act as a groundwater discharge avenue from the Moe Basin aquifers around the Moe Groundwater Management Area, this is variable in time and space.

30 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 1600 Latrobe/Moe River - Sampling Round 1 - September 2015 550 15 Latrobe/Moe River - Sampling Round 1 - September 2015 1000 Flow is lower and EC higher on the Moe River compared to the Latrobe River. Flow Gain 500 900 1400 Steady flow and EC gains observed along both rivers, suggesting steady baseflow gains. 13 EC of flow gain Small flow gains between Moe Drain 3 and the Latrobe confluence 450 Moe BFI:65% 800 1200 11 with likely low baseflow indices. The increase in EC between Moe 400 Drain 3 and Trafalgar East is difficult to explain as it would require 700 the groundwater to be significantly more saline than is expected 1000 9 Latrobe US Latrobe 350 based on GW bore EC. It may be caused by some other mechanism, 600 Lake Narracan Lake Gaining reach (Latrobe) Gaining reach such as nutrients from agricultural and/or urban discharges. 800 (Latrobe) 300 7 500 The Latrobe shows moderate flow gains with moderate BFIs. Flow (ML/d) Flow 250 400

600 (ML/d/km) Flow 5 Moe Drain Moe Latrobe US Latrobe

Willowgrove Latrobe BFI:50% 200 Moe BFI:71% 300

400 East 3 Electrical Conductivity (uS/cm) Conductivity Electrical Electrical Conductivity (uS/cm) Conductivity Electrical Latrobe BFI:30% Moe Drain Moe US Latrobe US Trafalgar Moe Drain 3 Drain Moe 150 Moderate to high rates of 200

Moe Drain 2 Drain Moe flow gain with high BFI on

Darnum Moe BFI:100% 200 Flow (ML/d) 1 Moe BFI:0% Gaining reach Gaining reach Neutral to slightly 100 the Moe River between 100 EC (uS/cm) Gaining reach Darnum and Moe Drain 2. 0 50 -1 0 0 5000 10000 15000 20000 25000 30000 0 5000 10000 15000 20000 25000 30000

450 Latrobe/Moe River - Sampling Round 2 - February 2016 650 10 Latrobe/Moe River - Sampling Round 2 - February 2016 1000 Baseflow gains on the Latrobe River and the Moe River between start of the Upstream of Moe Drain 2 and downstream of Trafalgar shows neutral conditions, and downstream Flow Gain 400 Moe Drain (Moe Drain 2) and Trafalgar East. of the confluence shows neutral to baseflow gaining conditions 900 8 Neutral upstream of the Moe Drain and between Trafalgar East and the 550 EC of flow gain 800 350 Latrobe confluence Moderate rates of flow gain with high BFI on the Latrobe River upstream of Flow (ML/d) 6 700 Latrobe US Latrobe Small flow gains between Moe Drain 3 and the Moe Drain Moe

Latrobe US Latrobe the Moe confluence.

300 Narracan Lake 450 Latrobe confluence with likely low baseflow EC (uS/cm) Gaining reach (Latrobe) Gaining reach Latrobe BFI:12% indices. The unexplainable increase in EC 600 250 Willowgrove (Latrobe) 4 between site 3 and Trafalgar East noted for 350 500 Moe BFI:57% September remains in February. 200 2 Moe BFI:100% Flow (ML/d) Flow 400 Flow (ML/d/km) Flow BFI:0% 150 250 Moe Flow Loss EC Drop 0 300 Electrical Conductivity (uS/cm) Conductivity Electrical 100 (uS/cm) Conductivity Electrical Latrobe Flow Loss EC Gain Moderate rates of flow gain 200 East 150 Moe Drain Moe US Latrobe US Trafalgar -2 with high BFI on the Moe River Neutral reach Gaining reach 3 Drain Moe 50 Neutral reach between site 2 at the start of 100 Moe Drain 2 Drain Moe Darnum the drain and site 3. 0 50 -4 0 0 5000 10000 15000 20000 25000 30000 0 5000 10000 15000 20000 25000 30000

400 Latrobe/Moe River - Sampling Round 3 - May 2016 650 10 Latrobe/Moe River - Sampling Round 3 - May 2016 1000 Baseflow gains on the Latrobe River and the Moe River between start of the Moe Drain (Moe Drain 2) and Trafalgar East. Flow Gain 900 350 Small flow gains between Moe Drain 3 and the Neutral upstream of the Moe Drain and between Trafalgar East and the 8 550 EC of flow gain Latrobe confluence with likely low baseflow Latrobe confluence 800 300 indices. The unexplainable increase in EC Flow (ML/d) Latrobe River: uncertain 6 between site 3 and Trafalgar East noted Latrobe River: Likely US Latrobe 700

- potential impacts of ET Narracan Lake 450 previously also present in May 250 EC (uS/cm) gaining reach 600 4 Moe Drain Moe

200 US Latrobe 350 500

Willowgrove Moe BFI:100% 2 Moe BFI:100% Flow (ML/d) Flow Latrobe BFI:95% 400

150 Moe Drain: (ML/d/km) Flow Moe Flow Gain EC Drop Likely gaining recah,reach, 250 Latrobe Flow Loss EC Gain 0 300 100 however inconclusive at Electrical Conductivity (uS/cm) Conductivity Electrical Electrical Conductivity (uS/cm) Conductivity Electrical this stage East Moderate rates of flow gain Moe Flow Loss EC Gain 200 Trafalgar Moe Drain Moe US Latrobe US 150 Moe Drain: 3 Drain Moe -2 with high BFI on the Moe River 50 Moe Drain: 2 Drain Moe Moe Drain: Flow loss and EC gain could be partly explained by evaporation Darnum Likely gaining between site 2 at the start of 100 Likely neutral Likely neutral on the Moe River however this would not explain the larger gain recah the drain and site 3. reach 0 reach 50 -4 with small flow loss observed on the Latrobe. 0 0 5000 10000 15000 20000 25000 30000 0 5000 10000 15000 20000 25000 30000

85 85 80 Latrobe River 80 Latrobe River 75 Moe River/Drain 75 Moe River/Drain 70 70 65 65

(mAHD) 60 (mAHD) 60 55 55

Land Surface Elevation SurfaceLand 50 Elevation SurfaceLand 50 45 45 0 5000 10000 15000 20000 25000 30000 0 5000 10000 15000 20000 25000 30000 Moe River Chainage (m) Moe River Chainage (m)

Figure 12 Flow and EC accretion profiles - Latrobe River Catchment 400,000 410,000 420,000 430,000 440,000 450,000 BLUE ROCK BLUE MOONDARRA RESERVOIR T LAKE ROCK YE LAKE Tanjil River U/S Blue Rock Reservoir RI R VE S # Int Baseflow: 53.4 ML/d R Latrobe River U/S Willow Grove 0# # Gaining reach Spring Field Monitoring Round 1 (23/09/2015 - 24/09/2015) Int Baseflow: 4.6 ML/d Gaining reach 0# Intrpretation of field observations from the spring monitoring round suggest: Tanjil River U/S Latrobe River - Gaining baseflow conditions along the length of the Latrobe River between Int Baseflow: 11.7 ML/d Willowgrove and Lake Narracan; and # Gaining reach *Note - significant flow losses but with gain - Gaining baseflow conditions along the Moe Drain / River between Darrnum in baseflow of a similar magnitude. This is and its confluence with the Latrobe River (upstream of Lake Narracan). However, likely due to extractions.

its gaining condition is less clear in the Drains lower reaches towards the Latrobe River U/S Moe Drain # 5,780,000 confluence, where neutral to slighlt gaining baseflow conditions are inferred. Int Baseflow: 15.7 ML/d 5,780,000

# R TA Gaining reach IVE N R J 0# IL 0# # LAKE Moe Drain (Site 2 - Site 3) #NARRACAN Moe Drain (Site 4 - Site 5) 0 Int Baseflow: 57.5 ML/d 0# LA TROB E

Gaining Reach Int Baseflow: 0 ML/d # Neutral to slightly gaining reach 0# RIVER U/S of Moe Drain

Int Baseflow: 10.8 ML/d 0# Gaining Reach # MOE DRAIN # Latrobe River U/S Lake Narracan S 0# Int Baseflow: 6.15 ML/d DE

M # WA K O # 0 E EE Gaining reach E CR RIVER OL H K Moe River U/S of Darnum R EE E R T C Int Baseflow: 65.0 ML/d Moe Drain (Site 3 - Site 4) A Gaining Reach 0# Baseflow uncertain W

# *Note - The increase in EC between Moe Drain 3 and Trafalgar East is difficult 5,770,000 5,770,000 R to explain as it would require the groundwater EA K to be significantly more saline than is expected B EE CR based on GW bore EC. It may be caused by L L R some other mechanism, such as nutrients from E E # agricultural and/or urban discharges. W IV R R O

AR BE Narracan Creek U/S Thorpdale Narracan Creek D/S Thorpdale REEK CAN C Int Baseflow: 8.6 ML/d RRA Int Baseflow: 17.3 ML/d NA EK Gaining reach CRE Gaining reach

# 0#

BLUE ROCK BLUE MOONDARRA Summer Field Monitoring Round 2 (04/02/2016 - 05/02/2016) T

# LAKE ROCK RESERVOIR Y R E Latrobe River U/S Willow Grove LAKE IV RS Interpretation of field observations from the summer monitoring round, suggest: Int Baseflow: 2.7 ML/d # ER - Gaining baseflow conditions along the length of the Latrobe River between Gaining reach 0# Tanjil River U/S Blue Rock Reservoir Willowgrove and Lake Narracan, i.e. no change from the inferred conditions *Reduced baseflow gains in summer Int Baseflow: 13.8 ML/d in spring. compared to spring 0# Gaining reach - Neutral baseflow conditions along much of the Moe River and Drain, with the *Reduced baseflow gains in summer compared to spring exception of the sub-reach between Site No. 2 and Site No. 3, where gaining conditions are inferred. From summer to spring, the Moe River and Drain has #

# become less baseflow dependent. Latrobe River U/S Moe Drain Int Baseflow: 2.4 ML/d Moderately gaining baseflow conditions are consistently experienced over spring and summer Gaining reach Tanjil River U/S Latrobe River 5,780,000 in the upper reaches of the Latrobe River, Tanjil River and Narracan Creek; however, baseflow *Reduced baseflow gains in sumemr 5,780,000

# R TA Int Baseflow: 1.4 ML/d gains are reduced in summer. compared to spring. N IVE J Gaining reach R I 0# L *Note - flow losses but with gain in baseflow of a similar magnitude, consistent Moe Drain (Site 2 - Site 3) results compared to spring. # LAKE Int Baseflow: 10.8 ML/d 0# Moe Drain (Site 4 - Site 5) NARRACAN Gaining reach # Int Baseflow: 0 ML/d 0 *Reduced baseflow gains in summer 0# LA TROB E compared to spring Neutral reach

# 0# RIVER U/S of Moe Drain Int Baseflow: 0 ML/d 0# Neutral reach # MOE DRAIN # Latrobe River U/S Lake Narracan Int Baseflow: 1.3 ML/d S 0# DE Gaining reach WA

MO # 0# EK Moe River U/S of Darnum E E *Reduced baseflow gains in summer E CR RIVER OL Int Baseflow: 7.9 ML/d compared to spring. H K R EE Gaining reach E R T C *Reduced baseflow in summer A compared to spring 0# W R

E #

Moe Drain (Site 3 - Site 4) VI 5,770,000 5,770,000 R Baseflow uncertain R EA K *Note - very large EC increase, could be attributed to range of L B EE # L CR reasons including: poor measurement, large flow losses, GW EC E end member should be higher (> 3500 uS/cm), or some other W R mechanism. O M Narracan Creek U/S Thorpdale Narracan Creek D/S Thorpdale AR Int Baseflow: 2.4 ML/d Int Baseflow: 4.9 ML/d BE CREEK Gaining reach ACAN Gaining reach *Reduced baseflow in summer RR NA EK *Reduced baseflow in summer compared to spring. CRE compared to spring. # 0#

BLUE ROCK BLUE MOONDARRA ROCK TY # LAKE RESERVOIR Autumn Field Monitoring Round 3 (16/05/2016 - 17/05/2016) R E LAKE IV RS # ER Interpretation of field observations from the autumn monitoring round, suggest: Latrobe River U/S Willow Grove #0 - Gaining baseflow conditions along the length of the Latrobe River between Int Baseflow: 1.9 ML/d Tanjil River U/S Blue Rock Reservoir Willowgrove and upstream of Moe Drain, i.e. no change from the inferred conditions Likely gaining reach #0 Int Baseflow: 11.8 ML/d in spring and summer. Likely gaining reach - Neutral baseflow conditions along much of the Moe River and Drain, with the exception of the sub-reach between Site No. 2 and Site No. 3, where gaining # # conditions are inferred. From summer to autumn, the Moe River and Drain has become more baseflow dependent. - Inconclusive conditions in the Latrobe River downstream of the Moe Drain, where flow Latrobe River U/S Moe Drain 5,780,000 losses and gains in EC could be partially attributed to evaporation impacts. Int Baseflow: 8.4 ML/d 5,780,000

# R TA Likely gaining reach IVE N R J #0 IL Tanjil River U/S Latrobe River Int Baseflow: 3.2 ML/d #0 # LAKE Likely gaining reach Moe Drain (Site 2 - Site 3) Moe Drain (Site 4 - Site 5) #0NARRACAN Int Baseflow: 0 ML/d Int Baseflow: 15.4 ML/d #0 LA TROB E Likely gaining reach Likely neutral reach

# #0 RIVER U/S of Moe Drain Int Baseflow: 0 ML/d #0

# MOE DRAIN Likely neutral reach # Latrobe River U/S Lake Narracan #0 Int Baseflow: 1.3 ML/d S ADE

MOE #0 No conclusion possible W EK # E *EC gains could potentially be attributed E CR RIVER OL to evaporation H K Moe River U/S of Darnum R EE E R Int Baseflow: 13.6 ML/d T C #0 A R W Gaining reach A Moe Drain (Site 3 - Site 4) E EK B E Baseflow uncertain C# R *Note - very large EC increase, could be attributed to range of 5,770,000 5,770,000 reasons including: poor measurement, large flow losses, GW EC Across seasons: end member should be higher (> 3500 uS/cm), or some other mechanism. # L Moderately gaining baseflow conditions are consistently experienced L R E E across seasons for the upper reaches of the Latrobe River, Tanjil River W IV R R and Narracan Creek; however, baseflow gains are generally reduced O in summer. The data suggests relatively variable seasonal baseflow M condtions along the Moe Drain with predominantly gaining conditions Narracan Creek U/S Thorpdale Narracan Creek D/S Thorpdale exhibited during spring and relatively neutral conditions during summer ACAN

# Int Baseflow: 5.8 ML/d ARR Int Baseflow: 9.5 ML/d and autumn. N EEK

Likely gaining reach # R Likely gaining reach #0 C

400,000 410,000 420,000 430,000 440,000 450,000 Field Sampling Neutral / Major Water Drain/Chann... 0# Location Gaining Area Latrobe River Baseflow Neutral River Catchment Classification Neutral / Losing Stream

Gaining Unclassified Channel

Job Number 31-32709 Paper Size A3 Department of Environment, Land, Water and Planning A 0 1,0002,000 4,000 6,000 8,000 Gippsland Rivers Baseflow Assessment Revision Date 20 May 2016 Metres Map Projection: Transverse Mercator Baseflow Interstation Analysis Horizontal Datum: GDA 1994 Grid: GDA 1994 MGA Zone 55 o Latrobe River Figure 13 G:\31\32709\GIS\Maps\Deliverables\3132709_KBM_A3P_Stage2_IntResults_Latrobe.mxd Hazelwood Drive (cnr Lignite Court) Morwell VIC 3840 Australia T 61 3 5136 5800 F 61 3 5136 5888 E [email protected] W www.ghd.com © 2016. Whilst every care has been taken to prepare this map, GHD (and DATA CUSTODIAN) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason. Data source: DEWLP, VICMaps, 2015; GHD, Baseflow Catchments, 2015; DELWP, WMIS Surface and Groundwater Data, 2015; Thiess,Field monitoring locations, 2015 - 2016. Created by:adrummond 5. Validation of Previous Baseflow Estimates

5.1 Introduction

The spot flow and EC observations are snapshots of streamflow and baseflow conditions and as such cannot reliably be used to make conclusions about the average or even typical baseflow and streamflow conditions of a given river or river reach. Rivers and groundwater systems are both highly dynamic, spatially and temporally. Hence, making generalisations about gaining or losing conditions of a given river is generally not appropriate, unless a consistent story of baseflow conditions can be constructed using the available data, and the data are appropriate (spatially and temporally) to facilitate this. That said, the observed streamflow and EC accretion data collected for this project provides a higher level of spatial resolution than does data from permanent gauging stations. The higher resolution (‘spot’) data can be used to investigate whether a more detailed understanding of the catchment can validate or contradict the baseflow estimates based on the broader reach scale mass balances, which only use data from permanent gauging station locations. Learnings from the analysis of the more spatially detailed field sampling data can be used to revise the broader methods and/or their application.

To evaluate and demonstrate this, baseflow estimates derived from the detailed sub-reach- scale mass balances (using the recently collected field data as outlined above in Section 4) were compared to the baseflow estimates derived from a reach scale mass balance of the broader reach (utilising only permanent gauging station locations). The latter was undertaken in Stage 1 of this project (GHD, 2015).The sum of baseflow gains based on detailed sub-reaches (i.e. those estimated using detailed field data) is different to that produced by the broader reach- scale mass balance results (i.e. using the less spatially detailed permanent gauging station data only). An example of this is observed by comparing Table 12 with Table 13 for the Macalister River.

Table 12 Broader Reach Scale EC Mass Balance Results for the Macalister River - using only sampling data from permanent gauging station locations (from Stage 1)

Upstream Downstream Qu Qd ECu ECd Diversion Baseflow1 (ML/d) (ML/d) (uS/cm) (uS/cm) (ML/d) (ML/d) DS Riverslea 108.5 49.3 129.6 143.1 60.02 12.9 Glenmaggie TOTAL 12.9 1 Groundwater end member of 1129 uS/cm adopted - which is the interstation groundwater end member EC for the reach b/w Glenmaggie 225204 and Riverslea 225247 (refer table 16 of the Stage 1 report) 2 EC of diversion estimated to be 143.1 uS/cm (same as downstream gauge) – NOTE: this is significantly higher than the estimate made possible by the more detailed field data shown in Table 13

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 33 Table 13 Sub-Reach Scale EC Mass Balance Results for the Macalister River - using recent field sampling data

Upstream Downstream Qu Qd ECu ECd Diversion Baseflow1 (ML/d) (ML/d) (uS/cm) (uS/cm (ML/d) (ML/d) DS US Newry 108.5 49.3 123.1 63.9 1.6 Glenmaggie Drain US Newry US Maffra 123.1 63.9 150.6 109.5 5.9 Drain Weir US Maffra DS Maffra 150.6 109.5 98.1 78.5 60.02 0.0 Weir Weir DS Maffra Riverslea 98.1 78.5 129.6 143.1 7.0 Weir TOTAL 14.4 1 Groundwater end member of 1129 uS/cm adopted - which is the interstation groundwater end member EC for the reach b/w Glenmaggie 225204 and Riverslea 225247 (refer table 16 of the Stage 1 report) 2 EC of diversion estimated to be 78.5 uS/cm (same as downstream gauge) There are two reasons for these differences:

1. The estimated EC of diverted water is improved when more spatially detailed data are available (i.e. a stream EC measurement immediately downstream of the offtake point); and

2. The equation adopted for the reach-scale mass balance includes a simplification equating the interstation runoff end member EC to the upstream gauge observed EC. This results in a different runoff end member EC used in the mass balance downstream along each sub-reach. An improvement to the reach-scale mass balance method would be to estimate the EC of diverted water based on a river chainage-based interpolation to the diversion location, from the two gauge locations at the upstream and downstream ends of each assessed reach. Assuming no knowledge of the interstation (sub-reach) catchment nor direct measurement of the diversion EC, this is a reasonable assumption.

For the above example, the diverted water EC estimated based on this technique would be 118.2 uS/cm. This compares to the more accurate EC estimate of 78.5 uS/cm that was measured during the field sampling directly downstream of the diversion location (Table 13). Using the interpolated EC to adjust the downstream EC provides a revised broader reach-scale mass balance estimate for the Macalister River, as shown in Table 14. Table 14 Broader Reach Scale EC Mass Balance Results for the Macalister River - using chainage-based interpolation of diverted water EC

Upstream Downstream Qu Qd ECu ECd Diversion Baseflow1 (ML/d) (ML/d) (uS/cm) (uS/cm (ML/d) (ML/d) DS Riverslea 108.5 49.3 129.6 143.1 60.02 11.9 Glenmaggie TOTAL 11.9 1 Groundwater end member of 1129 uS/cm adopted - which is the interstation groundwater end member EC for the reach b/w Glenmaggie 225204 and Riverslea 225247 (refer table 16 of the Stage 1 report) 2 EC of diversion estimated to be 118.2 uS/cm (using linear chainage-based interpolation). This results in an adjusted Qd of 109.3 ML/day and ECd of 135.2 uS/cm. It is noted that the initial baseflow estimate of 12.9 ML/d (Table 12) appears to be closer than the revised baseflow estimate of 11.9 ML/d to the most accurate interstation baseflow estimate of 14.4 ML/d based on sub-reach observation (Table 13). However, this is because the second identified issue (the runoff end member assumption) has not yet been addressed. To address

34 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 this second issue, the difference introduced by imperfect knowledge of the diversion end member will be removed as shown in Table 15. Table 15 Broader Reach Scale EC Mass Balance Results for the Macalister River - using measured diverted water EC

Upstream Downstream Qu Qd ECu ECd Diversion Baseflow1 (ML/d) (ML/d) (uS/cm) (uS/cm (ML/d) (ML/d) DS Riverslea 108.5 49.3 129.6 143.1 60.02 10.1 Glenmaggie TOTAL 10.1 1 Groundwater end member of 1129 uS/cm adopted - which is the interstation groundwater end member EC for the reach b/w Glenmaggie 225204 and Riverslea 225247 (refer table 16 of the Stage 1 report) 2 EC of diversion estimated to be 78.5 uS/cm (based on field measurement immediately downstream of the diversion location). This results in an adjusted Qd of 109.3 ML/day and ECd of 122.6 uS/cm. NOTE: this measurement would not normally be available for this broader reach-scale mass balance, which in practice utilises only permanent gauging station data. The reach-scale mass balance uses the equation, as outlined by GHD (2015):

( − ) = However, a more accurate representation of the( mass −balance) based upon our detailed analysis of the detailed sub-reach field data is:

Which can be written as: = + +

− ( − ) = Diversions (and outfalls) can be incorporated explicitly,( −avoiding) the need for adjustment of the downstream flow and EC as follows:

− ( − ) − = Where: ( − )

Qdiv and Cdiv are the flow rate and EC of diversions, respectively; and th CS is the runoff end member EC, which should be defined using the 95 percentile gauge stream EC at the most upstream gauge assessed for a given river catchment, unless a more appropriate estimate can be made. The key difference here, aside from explicit inclusion of diversions, is that the runoff end member has been redefined. Updated baseflow estimates for the above Macalister River example are shown in Table 16 and Table 17, based on the revised mass balance equation. Table 16 Revised Equation Broader Reach Scale EC Mass Balance Results for the Macalister River - using only sampling data from permanent gauging station locations

Upstream Downstream Qu Qd ECu ECd Diversion Baseflow1 (ML/d) (ML/d) (uS/cm) (uS/cm (ML/d) (ML/d) DS Riverslea 108.5 49.3 129.6 143.1 60.02 16.5 Glenmaggie TOTAL 16.5 1 Groundwater end member of 1129 uS/cm adopted - which is the interstation groundwater end member EC for the reach b/w Glenmaggie 225204 and Riverslea 225247 (refer table 16 of the Stage 1 report) 2. Runoff end member of 44 uS/cm adopted 3 EC of diversion estimated to be 78.5 uS/cm. NOTE: this measurement would not normally be available for this broader reach-scale mass balance, which in practice utilises only permanent gauging station data. This has been adopted to separate the issue of imperfect knowledge of EC of diverted water from the issue of the reach scale EC mass equation.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 35 Table 17 Revised Equation Sub-Reach Scale EC Mass Balance Results for the Macalister River - using recent field sampling data

Upstream Downstream Qu Qd ECu ECd Diversion Baseflow1 (ML/d) (ML/d) (uS/cm) (uS/cm (ML/d) (ML/d) DS US Newry 108.5 49.3 123.1 63.9 2.3 Glenmaggie Drain US Newry US Maffra 123.1 63.9 150.6 109.5 7.9 Drain Weir US Maffra DS Maffra 150.6 109.5 98.1 78.5 60.02 0.03 Weir Weir DS Maffra Riverslea 98.1 78.5 129.6 143.1 10.0 Weir TOTAL 20.2 1 Groundwater end member of 1129 uS/cm adopted - which is the interstation groundwater end member EC for the reach b/w Glenmaggie 225204 and Riverslea 225247 (refer table 16 of the Stage 1 report) 2. Runoff end member of 44 uS/cm adopted 3 EC of diversion estimated to be 78.5 uS/cm 4 Function gives a baseflow of -3.7 ML/day however the function cannot be used when EC is dropping as a baseflow loss does not result in a reduction in EC.

There remains a significant difference in baseflow estimates between the sub-reach and broad scale mass balances. However, this relates to the treatment of the EC drop across the Maffra Weir. While the spatially detailed sub-reach mass balance can isolate this anomaly, the broader reach mass balance cannot. The reach scale EC mass balance equation returns a negative baseflow of 3.7 ML/d for the sub reach between US Maffra Weir and DS Maffra Weir: in practice this is set to zero as the reach EC mass balance cannot be used to estimate baseflow losses which do not explain an EC reduction across a reach. However, if the value of this anomaly (3.7 ML/d) is added to the result for the broader reach scale mass balance (16.5 ML/day) the resultant baseflow (20.2 ML/d) is equal to the value for the detailed sub reach scale mass balance, demonstrating that the reach scale mass balance equation has been applied correctly (such that the sum of the sub reach baseflow contributions is equal to the broader reach baseflow contribution).

The recommended revised method for further baseflow studies is to estimate the EC of diverted water based on a river chainage-based interpolation to the diversion location, from the two gauge locations at the upstream and downstream ends of each assessed reach and adopting the revised reach scale mass balance equation. The results of the recommended revised method are shown in Table 18 and Table 19.

Table 18 Revised Equation Broader Reach Scale EC Mass Balance Results for the Macalister River - using only sampling data from permanent gauging station locations

Upstream Downstream Qu Qd ECu ECd Diversion Baseflow1 DS Riverslea 108.5 49.3 129.6 143.1 60.02 18.7 Glenmaggie TOTAL 18.7 1 Groundwater end member of 1129 uS/cm adopted - which is the interstation groundwater end member EC for the reach b/w Glenmaggie 225204 and Riverslea 225247 (refer table 16 of the Stage 1 report) 2. Runoff end member of 44 uS/cm adopted 3 EC of diversion estimated to be 118.2 uS/cm.

36 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Table 19 Recommended Revised Method Results: Sub-Reach Scale EC Mass Balance Results for the Macalister River - using recent field sampling data

Upstream Downstream Qu Qd ECu ECd Diversion Baseflow1 DS US Newry 108.5 49.3 123.1 63.9 2.3 Glenmaggie Drain US Newry US Maffra 123.1 63.9 150.6 109.5 7.9 Drain Weir US Maffra DS Maffra 150.6 109.5 98.1 78.5 60.02 0.03 Weir Weir DS Maffra Riverslea 98.1 78.5 129.6 143.1 10.0 Weir TOTAL 20.2 1 Groundwater end member of 1129 uS/cm adopted, runoff end member of 44 uS/cm adopted 2 EC of diversion estimated to be 78.5 uS/cm 3 Function gives a baseflow of -3.7 ML/day however the function cannot be used when EC is dropping as a baseflow loss does not result in a reduction in EC. Whilst there remain unresolvable differences between the detailed and broad-scale mass balances in this example, due to Maffra Weir, the baseflow estimates of both data sets can be considered very similar when the broader baseflow estimation uncertainties are considered – particularly those of the groundwater EC end member, as has been detailed in earlier work (GHD, 2014a, 2015). Table 20 illustrates that while the broader reach scale mass balance is not as precise as the detailed sub reach scale mass balance, the result is still well within the confidence interval based on uncertainty of the groundwater EC end member. Table 20 Comparison of baseflow contribution best estimates and uncertainty range for the Macalister River

Best Estimate based on detailed field sampling data1 20.2

Best Estimate based on broader reach scale mass balance1 18.7

Lower bound estimate based on broader reach scale mass balance2 6.2

Upper bound estimate based on broader reach scale mass balance3 59.6

1 Groundwater end member of 1129 uS/cm adopted 2 Groundwater end member of 3319 uS/cm adopted 3 Groundwater end member of 384 uS/cm adopted

The analysis of higher spatial resolution field sampling data demonstrates that while the broader reach scale mass balance based on permanent gauging station locations gives a different best estimate result, the uncertainty ranges comfortably encompass the more accurate estimate.

5.2 Recommendations

Based upon the reach-scale mass balance analyses and validation of the broader mass balances presented in Section 5.1, the following recommendations are made:

 Seek data to estimate the EC of diversions and outfalls to adequately account for them in the reach-scale mass balance. In lieu of observed data it may be an improvement to our method to adopt a linear interpolation of EC based on the distance of the offtake point from the upstream and downstream gauge locations, and the stream EC gauged at those locations.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 37  Adopt a refined equation to better represent the reach scale mass balance:

− ( − ) − Where: is the groundwater= -derived (baseflow) component of stream flow from ( − ) within the reach only, excluding baseflow inputs from further upstream; and are the gauged stream flow and EC at the downstream end of the reach; and are the gauged stream flow and EC at the upstream end; is runoff end member concentration, which should be defined using the 95th percentile gauge stream EC at the most upstream gauge assessed for a given river, unless a more appropriate estimate can be made; should be consistent across all sub-reaches assessed within a given broader river catchment unless information exist to substantiate that the runoff end member varies within the catchment; Qdiv and Cdiv are the flow rate and EC of diversions, respectively; and is the groundwater (baseflow) end member tracer concentration within the area thought to be contributing baseflow to the reach. This revised equation should result in the highest possible degree of consistency between detailed sub-reach scale mass balances and broader scale mass balances, however inconsistencies may remain in some cases as outlined in Section 5.1.

38 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 6. Effect of coal seam gas extraction on baseflow

6.1 Background

One of the objectives of this project is the quantification of the potential risk of coal seam gas and coal mining development to groundwater-surface water interactions and groundwater- dependent environmental values of Gippsland’s rivers. Coal seam gas extraction results in large scale aquifer depressurisation of the gas bearing formations, which has the potential to propagate up through the aquifer and result in declines in the water table aquifer. This in turn has the potential to reduce the hydraulic gradients to streams, reducing baseflow, and in some instances could lead to a change in hydrologic conditions from baseflow gaining to losing.

6.2 Coal Seam Gas studies

DELWP (2015) recently conducted a large series of studies investigating the potential impact of onshore natural gas extraction on groundwater and surface water users. The study concluded that potential impacts of depressurisation from coal seam gas in the Gippsland basin on surface water ecosystems are high in areas of close vicinity to the potential gas development and relatively low elsewhere (DELWP, 2015). Figure 14 shows the key results from DELWP (2015) indicating areas of potential impact to surface water ecosystems, where the high risk areas are near the coast, including the Gippsland Lakes and the lower reaches of the Thomson, Macalister and Latrobe Rivers. These reaches have significant baseflow contributions, as indicated in Stage 1 of this project (GHD, 2015). The results indicate that the upland areas are unlikely to be significantly impacted by coal seam gas extraction. It is important to note that this assessment assumed an extremely large production of Coal Seam Gas, of up to 510 GL/yr of additional extractions, compared to the current 100 GL/yr of extractions for offshore oil and gas production and 25 GL/yr of extractions from the Latrobe Valley coal mines. Figure 14 Potential impacts on surface water ecosystems from possible coal seam gas development (Figure 45 of DELWP, 2015).

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 39 6.3 Historic groundwater extractions

Historically, groundwater has been extracted from the Gippsland basin for a range of uses, including:

 Offshore extractions for oil and gas production;

 Licenced groundwater extractions for dewatering coal mines;

 Other (non-mining) licenced groundwater extractions; and

 Stock and domestic groundwater extractions.

Figure 15 illustrates the increase in groundwater extraction from the Gippsland basin over the last 75 years, with around 200 GL/yr of groundwater currently extracted, predominantly for offshore oil and gas and mining purposes (Table 21). Offshore extraction volumes are source from DELWP (2015d) and groundwater extraction volumes for mining purposes are sourced from GHD (2015b). It is noted that the majority of groundwater extractions occur from the deep confined Traralgon and Morwell Formation Aquifer Systems. Figure 15 Historic groundwater pumping from the Gippsland basin (Financial Year 1960 – 2015)

Table 21 Average and range in groundwater extraction from the Gippsland basin over the period 2000 – 2015

Groundwater Offshore Licenced Stock and Licenced (non- Extraction (GL/yr) extraction extractions for Domestic mining) mining extractions extractions

Average (2000 - 2015) 101 26 3 52 Range (2000 - 2015) 94 - 112 22 - 32 3 - 4 44 - 87

Review of historic groundwater trends from monitoring wells in proximity to the Latrobe Valley coal mines indicate that the potential effect of depressurisation of aquifers by the Latrobe Valley coal mines on shallow groundwater levels (and therefore groundwater-surface water interactions), is relatively insignificant in the (shallow) Haunted Hills and Yallourn Formations.

Figure 16 shows the groundwater hydrograph for monitoring well 52809, which is adjacent to Flynns Creek, in proximity to the Loy Yang mine. The groundwater hydrograph indicates that

40 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 while relatively steep declines are experienced in the Traralgon and Morwell Aquifer Systems where the groundwater extraction occurs, only minor drawdowns are experienced in the shallow Yallourn Aquifer (with the exception of the period following 2005, which corresponds with the prolonged drought period). This is supported by the hydrograph of the State Observation Bore Network monitoring well 103811 (Figure 17) which is located away from the mines, and experiences similar drawdown trends in the shallow Haunted Hill Aquifer System in the prolonged drought period following 2005.

6.4 Conclusions

It is noted that there is potential for onshore coal seam gas production to have significant impacts on baseflow in the Gippsland region. However, the magnitude of the impact depends on the location of the CSG development, the stratigraphy of the gas bearing formations and the scale of the CSG development. It is noted that the scenarios presented in DELWP (2015) most likely reflect the upper limit of the potential CSG production across Gippsland.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 41 Figure 16 Groundwater levels at 52809

42 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Figure 17 Groundwater levels at 103811

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 43 7. Conclusions and Recommendations

This study obtained targeted field data aimed at ground-truthing the baseflow estimates derived in Stage 1 of this study (GHD, 2015) for river reaches of interest to stakeholders. While highly localised studies and field data do not broadly inform the regional-scale conceptualisation and analysis of groundwater-surface water interactions, they do provide a valuable basis for constraining the estimates and thereby improving the confidence of more broad-scale approaches.

7.1 Field Sampling

Conclusions A targeted field work plan to undertake flow and EC accretion profiling was developed in consultation with DELWP, WGCMA and SRW, based on the key data gaps identified in Stage 1 (GHD, 2015) and tailored to the following key reaches of interest:

 Thomson River from Cowwarr to Wandocka, including Rainbow Creek (9 sampling locations);

 Moe Drain / Latrobe River upstream of Lake Narracan, including Tanjil River and Narracan Creek (12 sampling locations); and  Macalister River between Glenmaggie and Maffra Weir (5 sampling locations).

Spot sampling was undertaken for three sampling rounds over the study period to collect data for different seasons and regulated influences (irrigation releases):  Sampling Round 1: Spring 2015 (09/09/2015 – 28/09/2015). Capture flows at the start of the irrigation season.

 Sampling Round 2: Summer 2016 (12/01/2016 – 05/02/2016): Capture summer low flows.

 Sampling Round 3: Autumn 2016 (12/04/2016 – 17/05/2016): Capture flows outside of irrigation season.

Recommendations A key outcome of this study was the development of field sampling condition criteria to select conditions that will give the most accurate and representative results. It is recommended that future field investigation studies adopt similar sampling criteria developed in this study, where the key criteria are summarised below:

 Safety: the streamflow must be suitably low, to permit safe access to undertake flow gauging;  River operation: periods associated with large reservoir releases (such as flood mitigation type releases) should be avoided;

 Streamflow rate: undertake sampling when the flow rate was below the median flow for the month of year to reduce flow gauging uncertainty associated with high flows;

 Streamflow trends: sampling during peak streamflow following large rainfall events should be avoided and the flow trend should be steady (neither rising nor falling);  Streamflow profile (longitudinal): field monitoring should be undertaken when the difference in streamflow between sites is relatively stable;

44 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709  Forecast rainfall: sampling should be avoided when forecast rainfall over the proposed work period is greater than 5 mm.

Another recommendation from this study is to obtain field results for major ions in additional to EC for sites downstream of known agricultural or industrial discharges. This will confirm whether EC is representative of Chloride, or if it represents some other solute such as nitrogen. This has been conducted at key sampling locations along the Moe Drain as part of the third round of field investigations completed May 2016 (Section 3.3).

It is also recommended that any offtakes and outfalls occurring within the monitored reaches are also recorded as part of the field sampling program.

7.2 Revised baseflow estimates

Conclusions The spot flow and EC observations are snapshots of streamflow and baseflow conditions, and as such cannot reliably be used to make conclusions about the average or even typical baseflow and streamflow conditions of a given river or river reach. Rivers and groundwater systems are both highly dynamic, spatially and temporally. Therefore, making generalisations about gaining or losing conditions of a given river is generally not appropriate, unless a consistent story of baseflow conditions can be constructed using the available data, and the data are sufficiently abundant to facilitate this.

That said, the observed stream flow and EC accretion data collected for this project provides a higher level of spatial resolution than data from permanent gauging stations. The higher resolution (‘spot’) data can be used to investigate whether a more detailed understanding of the catchment can validate or contradict the baseflow estimates based on the broader reach scale mass balances, which only use data from permanent gauging stations. Learnings from the analysis of the more spatially detailed field sampling data can then be used to revise the broader methods and/or their application.

Results for all sampled reaches indicate that baseflow conditions (i.e. gain from or loss to groundwater) are variable along the reach length and between seasons.

Thomson River Across seasons, there are consistent baseflow gains exhibited along Rainbow Creek, which is more deeply incised into the landscape than the main channel of the Thomson River. Rainbow Creek likely forms a natural drain towards which groundwater from beneath the more elevated Thomson River will flow. Relatively consistent baseflow gains are exhibited in the reach immediately downstream of Cowwarr Weir, particularly during high river stage behind the weir. This is most likely due to the lower river bed and stage immediately downstream of the weir, effectively forming a drain towards which groundwater from beneath the weir is driven.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 45 uncertain along several reaches, where gains in EC could potentially be attributed to evaporation losses, rather than baseflow gains.

Latrobe River Moderately gaining baseflow conditions are consistently experienced across seasons for the upper reaches of the Latrobe River, Tanjil River and Narracan Creek; however, baseflow gains are generally reduced in summer. The data suggests relatively variable seasonal baseflow conditions along the Moe Drain, with predominantly gaining conditions exhibited during spring and relatively neutral conditions during summer and autumn.

Recommendations

Refinement to the sub-reach scale mass balance Based on the findings from the reach-scale mass balance analyses and validation of the broader mass balances, it is recommended that the following refinement to the method is adopted for subsequent baseflow assessments which are adopting the method trailed in this study:

− ( − ) − Refer to Section presented in 5.1=for full details of the refinement. This revised equation should ( − ) result in the highest possible degree of consistency between detailed sub-reach scale mass balances and broader scale mass balances.

A key aspect of this refinement is to incorporate an accurate estimate of flow and EC major diversions within the reach as this can have a significant impact on the outcomes of the reach scale mass balance.

Application of the method While application of the reach scale mass balance can provide a more accurate estimate of baseflows by removing some uncertainty associated with the runoff end member EC, there remains significant uncertainty in the baseflow estimates due to high uncertainty in the groundwater end member EC. The uncertainty may be reduced through undertaking EC and major ion sampling for a larger number of groundwater bores within the catchment; however, it is acknowledged that it could be a costly exercise. In cases where greater investment is justified, detailed transects that provide high resolution temporal information could be used to

46 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 better separate the regional groundwater end member characteristics from the bank storage mixing zone water.

Ideally, temporary gauging stations would be installed to continuously record flow and EC for a period of time that encompasses a range of flow, groundwater and management conditions. This would provide sufficient data to estimate the uncertainty of the measurements in a robust manner, which is not possible with the very small number of spot measurements undertaken in this study.

The application of the detailed reach-scale mass balance method at a sub-reach scale successfully validated the findings from the broader mass balance approach applied in Stage 1 of this study (GHD, 2015), as well as previous applications of the method (GHD 2013a; 2013b; 2014a). This study can be used as a guide to the application of the reach-scale mass balance for future studies. This study also highlighted the importance of identifying a number of limiting factors which reduce the reliability of the method, and account for them accordingly, such as:

 Impacts of flow regulation on the baseflow estimates

 Impacts of water storages on the baseflow estimates  Impacts of solute concentration through evapotranspiration along an interstation reach

 Impacts of diversions from the river and outfalls to the river in terms of flow and EC, and

 Scheduling of field work to increase applicability of results.

Baseflow database For specific river reaches of interest to water managers and other stakeholders, there would be value in implementing an ongoing annual program of spatially detailed field sampling and analyses, for which this study forms a well-developed template. Based on sampling results, a database of baseflow gains and flow losses along these reaches could be developed. This ‘baseflow conditions’ database would form a sound basis for more broadly characterising and better understanding priority river reaches in terms of seasonal baseflow conditions; in addition to how those conditions may change under variable climatic conditions and in response to land, water and resource developments. These broad characteristics could then be applied in:

 More robustly assessing the significance and value of groundwater inputs to environmental flows under a range of conditions

 Assessing threats to groundwater-dependent components of environmental flows, and

 Evaluating ongoing water management needs and options, licensing decisions, and approvals for significant land, water and resource developments.

7.3 Coal seam gas impact assessment

Conclusions This study completed a high level analysis to assess potential effects that coal seam gas extraction may have on groundwater – surface water interactions, drawing on finding from relevant literature. It is noted that there is potential for onshore coal seam gas production to have significant impacts on baseflow in the Gippsland region, as reported in DELWP (2015). However, the magnitude of the impact depends on the location of the CSG development, the stratigraphy of the gas bearing formations and the scale of the CSG development. It is noted that the scenarios presented in DELWP (2015b) most likely reflect the upper limit of the potential CSG production across Gippsland. Review of historic groundwater hydrographs in the region indicate the historic impacts of groundwater depressurisation for coal mining in the region have had limited impacts on the shallow aquifer systems.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 47 8. References

Brumley J. C. & Holdgate G. R. 1983. An Assessment of the Confined Groundwater Resource of the Moe Swamp Basin, Victoria, Austrlia. International Conference on Groundwater and Man, Vol. 1, pp. 41 – 50. Department of Resources and Energy, Canberra.

DSE (2012), Groundwater SAFE: Secure Allocations, Future Entitlements: SAFE Dataset Compilation Method Report.

DELWP (2015a), Water Measurement Information System (WMIS): Groundwater and Surface Water Data. Available from: http://data.water.vic.gov.au/monitoring.htm. Accessed April 2015. DELWP (2015b), Onshore natural gas water science studies - Gippsland Region Synthesis Report. June 2015.

DELWP (2015c), Onshore natural gas water science studies - Gippsland Region Assessment of Potential Impacts on Water Resource. June 2015.

DELWP (2015d), Onshore natural gas water science studies - Gippsland groundwater model. June 2015. Eckhardt, K. 2008. A comparison of baseflow indices, which were calculated with seven different baseflow separation methods. Journal of Hydrology (2008) 352, 168– 173.

GHD, 2010a. Report for ecoMarkets Groundwater Models. Groundwater Flow Modelling: West Gippsland CMA. Report prepared for Department of Sustainability and Environment, June 2010. GHD ref: 31/22410/181533.

GHD, 2010b. Report for ecoMarkets Groundwater Models. Groundwater Flow Modelling: East Gippsland CMA. Report prepared for Department of Sustainability and Environment, June 2010. GHD ref: 31/22410/181043.

GHD (2013a), Baseflow Estimation Method Pilot Trial: Characterising Groundwater Contribution to Baseflow Dependent Waterways. Report prepared for Department of Sustainability and Environment, February 2013. GHD ref: 31/28961/215174.

GHD (2013b), Groundwater Assessment – Baseflow Dependent Rivers: Characterising Baseflow Contribution to Baseflow Dependent Waterways. Report prepared for Department of Environment and Primary Industries, November 2013. GHD ref: 31/30271/224637.

GHD (2014a), Groundwater Assessment – Baseflow Dependent Rivers: Risk Assessment of Groundwater-Dependent Ecosystems using Baseflow Estimations. Report prepared for Department of Environment and Primary Industries, May 2014. GHD ref: 31/30271/231479

GHD (2014b). Latrobe Valley Groundwater and Land Level Monitoring Annual Report July 2013 to June 2014. Prepared for the Regional Groundwater Management Committee, December 2014. GHD ref: 31/12374/15.

GHD (2015) Assessment of Accuracy of Baseflow Studies: Latrobe, Thomson Macalister and Mitchell Rivers. Prepared for DELWP, May 2015. GHD ref: 31/32709/242581.

GHD (2015b) Latrobe Valley Groundwater and Land Level Monitoring – Annual Report July 2014 to June 2015. December 2015. Hofmann, H. (2011), Understanding connectivity within groundwater systems and between groundwater and rivers. School of Geoscience, Monash University, Clayton, Victoria, Australia. PhD, September 2011.

Jacobs SKM (2014), Moe Groundwater Catchment Resource Appraisal. Report prepared for the Department of Environment and Primary Industries (Victoria). Draft C. April 2014.

48 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Sellinger, C.E. 1996. Computer program for performing hydrograph separation using the rating curve method. NOAA Technical Memorandum ERL GLERL-100. November 1996.

SKM (2002), Sustainable Diversion Limit Project – Estimation of Sustainable Diversion Limit Parameters over winterfill periods in Victorian Catchments. Report prepared for the Department of Natural Resources and Environment (October 2002).

SKM (2012), Baseflow Separation and Analysis – Documentation of Method (Draft A). Report prepared for DSE as part of the SAFE project, March 2012.

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 49 50 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Appendices

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Appendix A – Sampling Locations

Appendix A1 – Sampling Photos: Thomson River

Appendix A2 – Sampling Photos: Macalister River

Appendix A3 – Sampling Photos: Latrobe River

52 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Appendix A1 – Field Photos Thomson River

225212A – THOMSON RIVER 225212A – THOMSON RIVER 225212A – THOMSON RIVER WANDOCKA 20150910 DS WANDOCKA 20150910 ME WANDOCKA 20150910 US

225227A RAINBOW CREEK DS 225227A RAINBOW CREEK DS 225227A RAINBOW CREEK DS COWWARR WEIR 20150909 DS COWWARR WEIR 20150909 ME COWWARR WEIR 20150909 US

225228A THOMSON RIVER TIMBER 225228A THOMSON RIVER TIMBER 225228A THOMSON RIVER TIMBER WEIR 20150909 DS WEIR 20150909 ME WEIR 20150909 US

225231A THOMSON RIVER US 225231A THOMSON RIVER US 225231A THOMSON RIVER US COWWARR WEIR 20150909 DS COWWARR WEIR 20150909 ME COWWARR WEIR 20150909 US

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 53 Appendix A1 – Field Photos Thomson River

225243A THOMSON RIVER DS 225243A THOMSON RIVER DS 225243A THOMSON RIVER DS RAINBOW 20150910 DS RAINBOW 20150910 ME RAINBOW 20150910 US

RAINBOW CREEK US OF THOMSON RAINBOW CREEK US OF THOMSON RAINBOW CREEK US OF THOMSON RIVER DS RIVER ME RIVER US

THOMSON RIVER DS OF STONY THOMSON RIVER DS OF STONY THOMSON RIVER DS OF STONY CREEK DS CREEK ME CREEK US

THOMSON RIVER US OF RAINBOW THOMSON RIVER US OF RAINBOW THOMSON RIVER US OF RAINBOW CREEK DS CREEK ME CREEK US

54 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Appendix A1 – Field Photos Thomson River

THOMSON RIVER US OF BACK THOMSON RIVER US OF BACK THOMSON SYPHON OUTFALL TO CREEK DS CREEK US RAINBOW CREEK

THOMSON SYPHON OUTFALL STONY CREEK THOMSON COWWARR WEIR CHANNEL TRIBUTARY 20150909 20150909 67.2 MLD RATED

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 55 Appendix A2 – Field Photos Macalister River

225204D MACALISTER DS 225204D MACALISTER DS 225204D MACALISTER DS GLENMAGGIE 20150928 DS GLENMAGGIE 20150928 ME GLENMAGGIE 20150928 US

225242A MACALISTER RIVER DS 225242A MACALISTER RIVER DS 225242A MACALISTER RIVER DS MAFFRA WEIR 20150928 DS MAFFRA WEIR 20150928 ME MAFFRA WEIR 20150928 US

225247A MACALISTER AT 225247A MACALISTER AT 225247A MACALISTER AT RIVERSLEA 20150928 DS RIVERSLEA 20150928 ME RIVERSLEA 20150928 US

MACALISTER RIVER BELLBIRD MACALISTER RIVER BELLBIRD MACALISTER RIVER BELLBIRD CORNER 20150928 DS CORNER 20150928 ME CORNER 20150928 US

MACALISTER RIVER US NEWRY MACALISTER RIVER US NEWRY MACALISTER RIVER US NEWRY DRAIN 20150928 DS DRAIN 20150928 ME DRAIN 20150928 US

56 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Appendix A3 – Field Photos Latrobe River

TANJIL RIVER US OF LATROBE RIVER ME 26021A NARRACAN CREEK MOE 26021A NARRACAN CREEK MOE 20150924 ME 20150924 DS

226402A MOE DRAIN TRAFALGAR MOE DRAIN SITE 3 20150923 ME MOE DRAIN SITE 2 START OF DRAIN SITE 4 20150923 20150923 ME

226021A NARRACAN CREEK MOE 20150924 US

226209B MOE RIVER DARNUM SITE 1 20150923 ME

LATROBE US LAKE NARRACAN LATROBE US LAKE NARRACAN LATROBE US LAKE NARRACAN BECKS BRIDGE 20150924 DS BECKS BRIDGE 20150924 ME BECKS BRIDGE 20150924 US

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 57 Appendix A3 – Latrobe River

226216A TANJIL RIVER TANJIL 226216A TANJIL RIVER TANJIL SOUTH 20150924 DS SOUTH 20150924 US

226204A LATROBE RIVER WILLOWGROVE 20150924 US

226204A LATROBE RIVER 226204A LATROBE RIVER WILLOWGROVE 20150924 DS WILLOWGROVE 20150924 ME

226218A NARRACAN CREEK 226218A NARRACAN CREEK THORPDALE 20150924 DS THORPDALE 20150924 US

LATROBE RIVER US MOE DRAIN LATROBE RIVER US MOE DRAIN LATROBE RIVER US MOE DRAIN 20150924 DS 20150924 ME 20150924 US

58 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Appendix A3 – Latrobe River

MOE RIVER US LATROBE SITE 5 MOE RIVER US LATROBE SITE 5 MOE RIVER US LATROBE SITE 5 20150924 DS 20150924 ME 20150924 US

226402A MOE DRAIN TRAFALGAR 226402A MOE DRAIN TRAFALGAR MOE DRAIN SITE 3 20150923 US SITE 4 20150923 DS SITE 4 20150923 US

MOE DRAIN SITE 3 20150923 DS MOE DRAIN SITE 2 START OF DRAIN MOE DRAIN SITE 2 START OF DRAIN 20150923 DS 20150923 US

226209B MOE RIVER DARNUM SITE 1 226209B MOE RIVER DARNUM SITE 1 20150923 DS 20150923 US

GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 | 59 Appendix B – Field Results

Appendix A1 – Field Results – Round 1

Appendix A2 – Field Results – Round 2

Appendix A3 – Field Results – Round 3

60 | GHD | Report for DELWP - Assessment of Accuracy of Baseflow Estimates, 31/32709 Gippsland Flow and EC Monitoring Client: GHD

Catchment: Macalister River Project No: 01106 Date: 28/09/2015 Site Date Time GHDischarge GPS Coordinates EC Temp Observations Temp ref M^3/S ML/D Easting's Northings 25C oC 225204D Macalister River D/S Glenmaggie T/G 28/09/2015 9:45 0.428 1.2553 108.5 55H0483003 5800534 49.3 13.8 Overcast Macalister River U/S Newry Drain (Banana Bridge) 28/09/2015 11:05 N/A 1.4253 123.1 55H0489788 5800257 63.9 15.4 Overcast Macalister River U/S Maffra Weir Pool (Bellbird Corn 28/09/2015 13:27 N/A 1.743 150.6 55H0496495 5800814 109.5 15.1 Overcast 225242A Macalister River D/S Maffra Weir T/G 28/09/2015 14:50 0.145 1.1356 98.1 55H0497839 5797233 78.5 13.8 Overcast 225247A Macalister River @ Riverslea 28/09/2015 16:20 0.767 1.5003 129.6 55H0498013 5791320 143.1 15.4 Overcast

Note: 1. Small outflow into Macalister River at Maffra Weir D/S measurement section, estimated at 2-3 ML/D, EC recorded at 240 EC and Temperature 24.0 C 2. Outflow from lake Glenmaggie had been cut back 3 days prior to Measurements 3. SRW Estimate 60 ML/D flowing down the Eastern Channel from Maffra Weir. 4. Possibly significant inflows into the Macalister River between Maffra Weir and Riverslea via the Serpentine Creek. Gippsland Flow and EC Monitoring Client: GHD

Catchment: Latrobe River Project No: 01106 Date: 23 & 24 /09/2015 Site Date Time GHDischarge GPS Coordinates EC Temp Observations Temp ref M^3/S ML/D Easting's Northings 25C oC Moe River/ Drain Sites 226209B Moe River @ Darnum (Site 1) 23/09/2015 10:57 1.259 1.484 128.2 55H0412653 5770881 340.2 10.7 Overcast Moe Drain Site 2 (Start of Drain) 23/09/2015 12:04 N/A 1.747 150.9 55H0418061 5772859 374.5 11.1 Overcast Moe Drain Site 3 23/09/2015 14:00 N/A 2.678 231.4 55H0425348 5773247 447.1 12 Overcast 226402A Moe Drain @ Trafalgar (Site 4) 23/09/2015 15:50 0.608 2.716 234.7 55H0431054 5774340 493.2 12 Overcast Moe River U/S Latrobe River (Site 5) 24/09/2015 9:04 N/A 2.783 240.5 55H0434822 5776437 488.6 9.48 Overcast Latrobe River sites 226204A Latrobe River @ Willowgrove 24/09/2015 12:15 1.216 5.068 437.9 55H0426324 5784168 92 8.85 Overcast Latrobe River U/S Moe Drain 24/09/2015 10:20 N/A 5.589 482.9 55H0434644 5777471 118.5 8.78 Overcast Latrobe River U/S Lake Narracan (Becks Bridge) 24/09/2015 13:50 N/A 15.494 1338.7 55H0437204 5776865 191.1 10.8 Overcast Tanjil River sites 226216A Tanjil River @ Tanjil South 24/09/2015 14:00 1.47 5.749 496.7 55H0433555 5783266 81 11.5 Overcast Tanjil River U/S Latrobe River 24/09/2015 11:45 N/A 5.592 483.1 55H0435773 5778493 98.5 10.8 Overcast Naracan Creek Sites 226218A Narracan Creek @ Thorpdale 24/09/2015 10:45 0.77 0.7625 65.9 55H0428801 5763694 124 9.94 Overcast 226021A Narracan Creek @ Moe 24/09/2015 15:05 0.578 1.028 88.8 55H0435960 5775844 219.2 16.6 Overcast

Note: 1.: Gippsland Flow and EC Monitoring Client: GHD

Catchment: Thomson River Project No: 01106 Date: 9 &10/09/2015 Site Date Time GHDischarge GPS Coordinates EC Temp Observations Temp ref M^3/S ML/D Easting's Northings 25C oC Day 1 Thomson River U/S Cowwarr Weir (225231A) 9/09/2015 10:10 2.243 4.265 368.5 55H0467153 5796673 73 9.59 Ocast / Showers Thomson River @ Timber Weir (225228A) 9/09/2015 11:40 0.406 3.036 262.3 55H0470165 5794579 73 9.92 Ocast / Showers Thomson River D/S Stony Creek 9/09/2015 13:42 NA 3.391 293.0 55H0473116 5795775 77 10.5 Ocast / Showers Rainbow Creek D/S Cowwarr Weir (225227A) 9/09/2015 12:15 0.142 0.6567 56.7 55H0470134 5794023 74 10.5 Ocast / Showers Thomson River U/S Back Creek 9/09/2015 14:45 NA 3.361 290.4 55H0477306 5794882 78 10.8 Ocast / Showers Stony Creek Crossing 9/09/2015 9:20 NA3 ML/D est (+/-1 ML/D) 55H0470715 5796623 142 10 Flow estimated Day 2 Rainbow Creek @ U/S Thomson River 10/09/2015 12:20 NA 0.78 67.4 55H0481671 5794000 101 12.4 Fine Thomson River @ U/S of Rainbow Creek 10/09/2015 11:00 NA 3.084 266.5 55H0481806 5793958 83 11 Fine Thomson River @ U/S of Rainbow Creek 10/09/2015 11:45 NA 3.117 269.3 55H0481806 5793958 83 11 Conformation Meas. Thomson River D/S Rainbow Creek (225243A) 10/09/2015 10:10 0.400 4.466 385.9 55H0481867 5793841 84 10.9 Fine Thomson River @ Wandocka (225212A) 10/09/2015 15:45 1.408 4.678 404.2 55H0481672 5793999 92 11.7 Fine Thomson River U/S Back Creek 10/09/2015 14:00 NA 2.911 251.5 55H0477306 5794882 78 11.5 Fine Syphon Outfall 10/09/2015 13:00 10 to 20 ML est 62 12.7 Flow estimated

Note: 1. SRW commented Cowwarr Channel running @ 67.2mld 9/9/2015 All day no change 2. Logger @ visit Cowwarr HG 64.927 TG 0.139 3. Shaded lines indicate additional site information Gippsland Flow and EC Monitoring Client: GHD

Catchment: Thomson River Project No: 01106 Date: 12 &13/01/2016 Site Date Time GHDischarge GPS Coordinates EC Temp Observations Temp ref M^3/S ML/D Easting's Northings 25C oC Day 1 Thomson River U/S Cowwarr Weir (225231A) 12/01/2016 8:46 2.082 2.6806 231.6 55H0467153 5796673 83 22.9 Weather is Fine Thomson River @ Timber Weir (225228A) 12/01/2016 10:59 0.277 1.465 126.6 55H0470165 5794579 91 24.2 Weather is Fine Thomson River D/S Stony Creek 12/01/2016 12:32 NA 1.5806 136.6 55H0473116 5795775 99 24.3 Weather is Fine Rainbow Creek D/S Cowwarr Weir (225227A) 12/01/2016 11:25 0.14 0.665 57.5 55H0470134 5794023 91 24.5 Weather is Fine Thomson River U/S Back Creek 12/01/2016 13:38 NA 1.2824 110.8 55H0477306 5794882 100 24.2 Weather is Fine Stony Creek Crossing 12/01/2016 8:20 NA2ML/D estimated 55H0470715 5796623 Flow estimated Day 2 Rainbow Creek @ U/S Thomson River 13/01/2016 10:16 NA 0.6123 52.9 55H0481671 5794000 108 24 Weather is Fine Thomson River @ U/S of Rainbow Creek 13/01/2016 9:19 NA 1.3604 117.5 55H0481806 5793958 103 22 Weather is Fine Thomson River D/S Rainbow Creek (225243A) 13/01/2016 8:07 NA 2.4348 210.4 55H0481867 5793841 100 22.3 Weather is Fine Thomson River @ Wandocka (225212A) 13/01/2016 13:07 1.081 1.8694 161.5 55H0481672 5793999 107 23.6 Weather is Fine Thomson River U/S Back Creek 13/01/2016 12:05 NA 1.4005 121.0 55H0477306 5794882 98 23.7 Weather is Fine Syphon Outfall 13/01/2016 0:00 NA 40ML/D estimated Flow estimated

Note: 1. D Johnson from SRW provided there was 20-23ML/D being released down the Cowwarr Channel 2. Shaded areas indicate additional site information G F EC M C: GHD

C: M R P N: 01106 D: 14/04/2016 S D T GH D GPS C EC T O T M3/S ML/D E' N 25C C 225204D M R D/S G T/G 14/04/2016 9:40 0.451 1.6475 142.3 55H0483003 5805034 66 17.7 S M R U/S N D (B B) 14/04/2016 10:40 NA 1.472 127.2 55H0489788 5800257 75 18.2 S M R U/S M W P (B C)14/04/2016 11:45 NA 1.665 143.9 55H0496495 5800814 90 17.6 O 225242A M R D/S M W T/G 14/04/2016 13:45 0.110 0.719 62.1 55H0497839 5797233 110 17.6 O 225247A M R @ R 14/04/2016 15:25 0.650 0.8569 74.0 55H0498013 5791320 152 17.8 O

N: 1. M W HG 20.868, P C, G2 C, S 0.182, TG 0.110. A -225242A. 2. I M G DS M W TG . 2-3 EC 534 T 24.7 3. S C@S 3-5 EC 374 T 18.3. S C@S 3-5 EC 374 T 18. 4. C C (US B C) 2 EC 560 T16.5 5. SRW I 10 DS B B Gippsland Flow and EC Monitoring Client: GHD

Catchment: Macalister River Project No: 01106 Date: 14/01/2016 Site Date Time GHDischarge GPS Coordinates EC Temp Observations Temp ref M^3/S ML/D Easting's Northings 25C oC 225204D Macalister River D/S Glenmaggie T/G 14/01/2016 8:16 0.525 2.9652 256.2 55H0483003 5800534 62 22.6 Weather is Fine Macalister River U/S Newry Drain (Banana Bridge) 14/01/2016 10:27 NA 2.832 244.7 55H0489788 5800257 60 21.8 Weather is Fine Macalister River U/S Maffra Weir Pool (Bellbird Corn 14/01/2016 11:44 NA 2.988 258.2 55H0496495 5800814 80 24.5 Weather is Fine 225242A Macalister River D/S Maffra Weir T/G 14/01/2016 12:29 0.145 1.0799 93.3 55H0497839 5797233 110 24.9 Weather is Fine 225247A Macalister River @ Riverslea 14/01/2016 14:18 0.777 1.494 129.1 55H0498013 5791320 209 23.7 Weather is Fine

Note: Gippsland Flow and EC Monitoring Client: GHD

Catchment: Latrobe River Project No: 01106 Date: 4 & 5 /02/2016 Site Date Time GHDischarge GPS Coordinates EC Temp Observations Temp ref M^3/S ML/D Easting's Northings 25C oC Moe River/ Drain Sites 226209B Moe River @ Darnum (Site 1) 4/02/2016 9:28 0.991 0.1704 14.7 55H0412653 5770881 359 18.5 Weather is Fine Moe Drain Site 2 (Start of Drain) 4/02/2016 11:00 NA 0.1597 13.8 55H0418061 5772859 340 19.8 Weather is Fine Moe Drain Site 3 4/02/2016 12:33 NA 0.362 31.3 55H0425348 5773247 472 20.1 Weather is Fine Inflows entering drain just 226402A Moe Drain @ Trafalgar (Site 4) 4/02/2016 13:28 0.3 0.4471 38.6 55H0431054 5774340 570 21.4 upstream Moe River U/S Latrobe River (Site 5) 4/02/2016 14:52 NA 0.4489 38.8 55H0434822 5776437 547 22 Weather is Fine Moe River U/S Latrobe River (Site 5) 5/02/2016 8:23 NA 0.41 35.4 55H0434822 5776437 576 19.5 Weather is Fine Latrobe River sites 226204A Latrobe River @ Willowgrove 5/02/2016 10:37 0.965 2.6334 227.5 55H0426324 5784168 98 18.5 Weather is Fine Latrobe River U/S Moe Drain 5/02/2016 7:46 NA 3.2011 276.6 55H0434644 5777471 111 18.7 Weather is Fine Latrobe River U/S Lake Narracan (Becks Bridge) 5/02/2016 10:50 NA 4.728 408.5 55H0437204 5776865 158 19.5 Weather is Fine Tanjil River sites 226216A Tanjil River @ Tanjil South 5/02/2016 12:23 1.075 1.295 111.9 55H0433555 5783266 88 18.2 Weather is Fine Tanjil River U/S Latrobe River 5/02/2016 12:23 NA 1.034 89.3 55H0435773 5778493 98 19.8 Weather is Fine Naracan Creek Sites 226218A Narracan Creek @ Thorpdale 5/02/2016 9:25 0.42 0.1505 13.0 55H0428801 5763694 158 16.6 Weather is Fine 226021A Narracan Creek @ Moe 5/02/2016 9:37 0.391 0.206 17.8 55H0435960 5775844 283 18.2 Weather is Fine

Note: 1.: Tanjil River rising/falling quickly due to unsteady outflows from Blue Rock 2. Estimated flows 10 -15ML/D entering Moe Drain just upstream of site 226402A Moe Drain at Trafalgar East from small drain G F EC M C: GHD

C: T R P N: 01106 D:12 &13/04/2016 S D T GH D GPS C EC T O T M3/S ML/D E' N 25C C D 1 T R U/S C W (225231A) 12/04/2016 11:30 1.974 1.9816 171.2 55H0467153 5796673 67 15.5 O T R U/S C W (225231A) 12/04/2016 12:10 1.975 1.9186 165.7 55H0467153 5796673 67 15.5 O T R @ T W (225228A) 12/04/2016 13:00 0.259 1.2218 105.6 55H0470165 5794579 67 16.3 O T R D/S S C 12/04/2016 13:50 NA 1.2346 106.7 55H0473116 5795775 68 16.3 O R C D/S C W (225227A) 12/04/2016 13:55 0.117 0.553 48.0 55H0470134 5794023 67 16.4 O T R U/S B C 12/04/2016 15:40 NA 1.2804 110.6 55H0477306 5794882 70 16.4 O S C C 12/04/2016 9:35 NA N F 55H0470715 5796623 D 2 R C @ U/S T R 13/04/2016 14:00 NA 0.5882 50.8 55H0481671 5794000 87 18.1 O T R @ U/S R C 13/04/2016 13:05 NA 1.884 102.7 55H0481806 5793958 71 16.5 O T R D/S R C (225243A) 13/04/2016 11:30 0.164-0.130 2.1678 187.3 55H0481867 5793841 75 17.2 S T R @ W (225212A) 13/04/2016 15:10 1.110-1.130 2.1781 188.2 55H0489680 5793138 72 16.8 O T R U/S B C 13/04/2016 10:15 NA 1.2457 107.6 55H0477306 5794882 70 15.9 O S O 13/04/2016 14:30 NA V 55H0481727 5793896 65 18.9

N: 1. D J SRW 6 ML/D C C 2. S O 30-40 @ 11:30 5-10 @ 12:50, V -225243A Gippsland Flow and EC Monitoring Client: GHD

Catchment: Latrobe River Project No: 01106 Date: 16/5/2016 - 17/5/2016 Site Date Time GH Discharge GPS Coordinates EC Temp Observations Temp ref M^3/S ML/D Easting's Northings 25C oC Moe River/ Drain Sites 226209B Moe River @ Darnum (Site 1) 16/05/2016 11:10 1.038 0.2496 21.6 55H0412653 5770881 412 10.8 Windy/Overcast Moe Drain Site 2 (Start of Drain) 16/05/2016 12:15 - 0.3010 26.0 55H0418061 5772859 396 11.5 Windy/Overcast Moe Drain Site 3 16/05/2016 13:43 - 0.4439 38.4 55H0425348 5773247 484 11.6 Windy/Overcast 226402A Moe Drain @ Trafalgar (Site 4) 16/05/2016 15:02 0.323 0.5648 48.8 55H0431054 5774340 577 12.2 Inflow upstream Est' 2-5ML/D Moe River U/S Latrobe River (Site 5) 16/05/2016 16:01 - 0.5194 44.9 55H0434822 5776437 574 12.6 Windy/Overcast Moe River U/S Latrobe River (Site 5) 17/05/2016 12:41 - 0.4980 43.0 55H0434822 5776437 573 12.7 Windy/Overcast Latrobe River sites 226204A Latrobe River @ Willowgrove 17/05/2016 10:06 0.871 1.8663 161.2 55H0426324 5784168 99 12.2 Windy/Overcast Latrobe River U/S Moe Drain 17/05/2016 11:03 - 2.0121 173.8 55H0434644 5777471 136 12.4 Windy/Overcast Latrobe River U/S Lake Narracan (Becks Bridge) 17/05/2016 09:01 - 4.2250 365.0 55H0437204 5776865 195 12.5 Windy/Overcast Tanjil River sites 226216A Tanjil River @ Tanjil South 17/05/2016 11:21 1.079 1.2723 109.9 55H0433555 5783266 81 14.2 Windy/Overcast Tanjil River U/S Latrobe River 17/05/2016 12:45 - 1.2460 107.7 55H0435773 5778493 103 13.5 Windy/Overcast Naracan Creek Sites 226218A Narracan Creek @ Thorpdale 17/05/2016 08:44 0.622 0.4567 39.5 55H0428801 5763694 135 12.0 Windy/Overcast 226021A Narracan Creek @ Moe 17/05/2016 08:05 0.487 0.5070 43.8 55H0435960 5775844 225 12.3 Windy/Overcast

Note: 226216A - Pumping from gauge pool at time of measurement, stage rising from 1.061 - 1.097. Flow from Blue rock dam increased during measurement

VENTIA PTY LIMITED ATTN: Wayne Ross 13 Fulton Rd Maffra VIC 3862 AUSTRALIA

27/05/2016

Dear Wayne

Please find attached the Final Analytical Report for

Customer Service Request: 142829-2016-CSR-18 Account: 142829 Project: AWQC-104028 Ventia - River/Ground Water Investigation - Non routine 15/6

This report has also been sent to: Wayne Ross

AWQC Sample Receipt hours are Monday and Tuesday 8:30am to 8pm and Wednesday, Thursday and Friday 8:30am to 4:30pm.

Yours sincerely,

Darren Seebohm Customer Services Officer [email protected] +61 8 7424 2150

Page 1 of 7

ABN 69336525019 A business unit of the South Australian Water Corporation FINAL REPORT: 183080 This report shall not be reproduced, except in full without the written permission of the laboratory.

Report Information

Project Name AWQC-104028 Customer VENTIA PTY LIMITED CSR_ID 142829-2016-CSR-18

Analytical Results Customer Sample Description Sample Location 1 Sampling Point 90641-VENTIA PTY LIMITED Sampled Date 16/05/2016 1:45:00PM Sample Received Date 17/05/2016 1:53:50PM Sample ID 2016-003-2835 Status Endorsed Collection Type Customer Collected

Inorganic Chemistry - Metals LOR Result Sample temperature at time of receipt 2.9°C Calcium TIC-004 W09-023 Calcium 0.1 11 .1 mg/L Magnesium TIC-004 W09-023 Magnesium 0.05 10.7 mg/L Potassium TIC-006 W09-023 Potassium 0.040 4.62 mg/L Sodium TIC-004 W09-023 Sodium 0.1 57.3 mg/L Sulphur TIC-004 W09-023 Sulphate 1.5 13.2 mg/L

Inorganic Chemistry - Nutrients LOR Result Sample temperature at time of receipt 2.9°C Ammonia as N T0100-01 W09-023 Ammonia as N 0.005 0.036 mg/L Chloride T0104-02 W09-023 Chloride 4.0 114 mg/L Fluoride T0105-01 W09-023 Fluoride 0.10 0.10 mg/L Nitrate + Nitrite as N T0161-01 W09-023 Nitrate + Nitrite as N 0.003 0.907 mg/L Nitrite as N T0107-01 W09-023 Nitrite as Nitrogen 0.003 0.006 mg/L Silica - Reactive T0111-01 W09-023 Silica - Reactive 1 11 mg/L

Corporate Accreditation Notes No.1115 Chemical and 1. The last figure of the result value is a significant figure. Biological Testing 2. Samples are analysed as received. Accredited for compliance 3. # determination of the component is not covered by NATA Accreditation . with ISO/IEC 17025 4. ^ indicates result is out of specification according to the reference Guideline. Refer to Report footer. 5. * indicates incident have been recorded against the sample. Refer to Report footer. 6. & Indicates the results have changed since the last issued report. 7. The Limit of Reporting (LOR) is the lowest concentration of analyte which is reported at the AWQC and is based on the LOQ rounded up to a more readily used value. The Limit of Quantitation (LOQ) is the lowest concentration of analyte for which quantitative results may be obtained within a specified degree of confidence. 8. Where collection type is AWQC Collect, NATA has confirmed that due to a robust system in place for maintaining the temperature integrity for samples collected by AWQC’s Field Laboratory Services, the recording of temperature when samples arrive at the AWQC is out of scope. Page 2 of 7 9. Where applicable Measurement of Uncertainty is available upon request

ABN 69336525019 A business unit of the South Australian Water Corporation FINAL REPORT: 183080 This report shall not be reproduced, except in full without the written permission of the laboratory.

Inorganic Chemistry - Physical LOR Result Sample temperature at time of receipt 2.9°C Alkalinity Carbonate Bicarbonate and Hydroxide T0101-01 W09-023 Alkalinity as Calcium Carbonate 31 mg/L Bicarbonate 38 mg/L Carbonate 0 mg/L Hydroxide 0 mg/L Conductivity & Total Dissolved Solids T0016-01 W09-023 Conductivity 1 482 µScm Total Dissolved Solids (by EC) 1.0 260 mg/L pH T0010-01 W09-023 pH 7.1 pH units

Corporate Accreditation Notes No.1115 Chemical and 1. The last figure of the result value is a significant figure. Biological Testing 2. Samples are analysed as received. Accredited for compliance 3. # determination of the component is not covered by NATA Accreditation . with ISO/IEC 17025 4. ^ indicates result is out of specification according to the reference Guideline. Refer to Report footer. 5. * indicates incident have been recorded against the sample. Refer to Report footer. 6. & Indicates the results have changed since the last issued report. 7. The Limit of Reporting (LOR) is the lowest concentration of analyte which is reported at the AWQC and is based on the LOQ rounded up to a more readily used value. The Limit of Quantitation (LOQ) is the lowest concentration of analyte for which quantitative results may be obtained within a specified degree of confidence. 8. Where collection type is AWQC Collect, NATA has confirmed that due to a robust system in place for maintaining the temperature integrity for samples collected by AWQC’s Field Laboratory Services, the recording of temperature when samples arrive at the AWQC is out of scope. Page 3 of 7 9. Where applicable Measurement of Uncertainty is available upon request

ABN 69336525019 A business unit of the South Australian Water Corporation FINAL REPORT: 183080 This report shall not be reproduced, except in full without the written permission of the laboratory.

Analytical Results Customer Sample Description Sample Location 2 Sampling Point 90641-VENTIA PTY LIMITED Sampled Date 16/05/2016 3:25:00PM Sample Received Date 17/05/2016 1:49:35PM Sample ID 2016-003-2836 Status Endorsed Collection Type Customer Collected

Inorganic Chemistry - Metals LOR Result Sample temperature at time of receipt 2.9°C Calcium TIC-004 W09-023 Calcium 0.1 10.7 mg/L Magnesium TIC-004 W09-023 Magnesium 0.05 12.1 mg/L Potassium TIC-006 W09-023 Potassium 0.040 5.09 mg/L Sodium TIC-004 W09-023 Sodium 0.1 73.6 mg/L Sulphur TIC-004 W09-023 Sulphate 1.5 13.5 mg/L

Inorganic Chemistry - Nutrients LOR Result Sample temperature at time of receipt 2.9°C Ammonia as N T0100-01 W09-023 Ammonia as N 0.005 0.035 mg/L Chloride T0104-02 W09-023 Chloride 4.0 138 mg/L Fluoride T0105-01 W09-023 Fluoride 0.10 <0.1 mg/L Nitrate + Nitrite as N T0161-01 W09-023 Nitrate + Nitrite as N 0.003 1.06 mg/L Nitrite as N T0107-01 W09-023 Nitrite as Nitrogen 0.003 0.005 mg/L Silica - Reactive T0111-01 W09-023 Silica - Reactive 1 11 mg/L

Inorganic Chemistry - Physical LOR Result Sample temperature at time of receipt 2.9°C Alkalinity Carbonate Bicarbonate and Hydroxide T0101-01 W09-023 Alkalinity as Calcium Carbonate 28 mg/L

Corporate Accreditation Notes No.1115 Chemical and 1. The last figure of the result value is a significant figure. Biological Testing 2. Samples are analysed as received. Accredited for compliance 3. # determination of the component is not covered by NATA Accreditation . with ISO/IEC 17025 4. ^ indicates result is out of specification according to the reference Guideline. Refer to Report footer. 5. * indicates incident have been recorded against the sample. Refer to Report footer. 6. & Indicates the results have changed since the last issued report. 7. The Limit of Reporting (LOR) is the lowest concentration of analyte which is reported at the AWQC and is based on the LOQ rounded up to a more readily used value. The Limit of Quantitation (LOQ) is the lowest concentration of analyte for which quantitative results may be obtained within a specified degree of confidence. 8. Where collection type is AWQC Collect, NATA has confirmed that due to a robust system in place for maintaining the temperature integrity for samples collected by AWQC’s Field Laboratory Services, the recording of temperature when samples arrive at the AWQC is out of scope. Page 4 of 7 9. Where applicable Measurement of Uncertainty is available upon request

ABN 69336525019 A business unit of the South Australian Water Corporation FINAL REPORT: 183080 This report shall not be reproduced, except in full without the written permission of the laboratory.

Alkalinity Carbonate Bicarbonate and Hydroxide T0101-01 W09-023 Bicarbonate 34 mg/L Carbonate 0 mg/L Hydroxide 0 mg/L Conductivity & Total Dissolved Solids T0016-01 W09-023 Conductivity 1 573 µScm Total Dissolved Solids (by EC) 1.0 310 mg/L pH T0010-01 W09-023 pH 7.1 pH units

Corporate Accreditation Notes No.1115 Chemical and 1. The last figure of the result value is a significant figure. Biological Testing 2. Samples are analysed as received. Accredited for compliance 3. # determination of the component is not covered by NATA Accreditation . with ISO/IEC 17025 4. ^ indicates result is out of specification according to the reference Guideline. Refer to Report footer. 5. * indicates incident have been recorded against the sample. Refer to Report footer. 6. & Indicates the results have changed since the last issued report. 7. The Limit of Reporting (LOR) is the lowest concentration of analyte which is reported at the AWQC and is based on the LOQ rounded up to a more readily used value. The Limit of Quantitation (LOQ) is the lowest concentration of analyte for which quantitative results may be obtained within a specified degree of confidence. 8. Where collection type is AWQC Collect, NATA has confirmed that due to a robust system in place for maintaining the temperature integrity for samples collected by AWQC’s Field Laboratory Services, the recording of temperature when samples arrive at the AWQC is out of scope. Page 5 of 7 9. Where applicable Measurement of Uncertainty is available upon request

ABN 69336525019 A business unit of the South Australian Water Corporation FINAL REPORT: 183080 This report shall not be reproduced, except in full without the written permission of the laboratory.

AWQC Signatories

Roger Kennedy - Snr Technical Officer - Method Dev

Corporate Accreditation Notes No.1115 Chemical and 1. The last figure of the result value is a significant figure. Biological Testing 2. Samples are analysed as received. Accredited for compliance 3. # determination of the component is not covered by NATA Accreditation . with ISO/IEC 17025 4. ^ indicates result is out of specification according to the reference Guideline. Refer to Report footer. 5. * indicates incident have been recorded against the sample. Refer to Report footer. 6. & Indicates the results have changed since the last issued report. 7. The Limit of Reporting (LOR) is the lowest concentration of analyte which is reported at the AWQC and is based on the LOQ rounded up to a more readily used value. The Limit of Quantitation (LOQ) is the lowest concentration of analyte for which quantitative results may be obtained within a specified degree of confidence. 8. Where collection type is AWQC Collect, NATA has confirmed that due to a robust system in place for maintaining the temperature integrity for samples collected by AWQC’s Field Laboratory Services, the recording of temperature when samples arrive at the AWQC is out of scope. Page 6 of 7 9. Where applicable Measurement of Uncertainty is available upon request

ABN 69336525019 A business unit of the South Australian Water Corporation FINAL REPORT: 183080 This report shall not be reproduced, except in full without the written permission of the laboratory.

Analytical Method

Analytical Method Code Description Reference Method T0010-01 Determination of pH APHA 4500-H B T0016-01 Determination of Conductivity APHA 2510 B T0100-01 Ammonia/Ammonium - Automated Flow Colorimetry APHA 4500-NH3 G T0101-01 Alkalinity - Automated Acidimetric Titration APHA 2320 B T0104-02 Chloride - Discrete Analyser APHA 4500-Cl- E T0105-01 Fluoride by ISE APHA 4500-F- C T0107-01 Nitrite - Automated Flow Colorimetry APHA 4500-NO3-I T0111-01 Silica by automated fow colorimetry APHA 4500-Si02 T0161-01 Nitrate + Nitrate (NOx) - Automated Flow Colorimetry APHA 4500-NO3-I TIC-004 Determination of Metals - ICP Spectrometry by ICP2 APHA 3120 TIC-006 Elemental Analysis By ICP- MS EPA method 200.8 W-052 Preparation of Samples for Metal Analysis APHA 3030A to 3030D

Sampling Method

Sampling Method Code Description W09-023 Sampling Method for Chemical Analyses

Laboratory Information

Laboratory NATA accreditation ID Inorganic Chemistry - Metals 1115 Inorganic Chemistry - Nutrients 1115 Inorganic Chemistry - Physical 1115

Corporate Accreditation Notes No.1115 Chemical and 1. The last figure of the result value is a significant figure. Biological Testing 2. Samples are analysed as received. Accredited for compliance 3. # determination of the component is not covered by NATA Accreditation . with ISO/IEC 17025 4. ^ indicates result is out of specification according to the reference Guideline. Refer to Report footer. 5. * indicates incident have been recorded against the sample. Refer to Report footer. 6. & Indicates the results have changed since the last issued report. 7. The Limit of Reporting (LOR) is the lowest concentration of analyte which is reported at the AWQC and is based on the LOQ rounded up to a more readily used value. The Limit of Quantitation (LOQ) is the lowest concentration of analyte for which quantitative results may be obtained within a specified degree of confidence. 8. Where collection type is AWQC Collect, NATA has confirmed that due to a robust system in place for maintaining the temperature integrity for samples collected by AWQC’s Field Laboratory Services, the recording of temperature when samples arrive at the AWQC is out of scope. Page 7 of 7 9. Where applicable Measurement of Uncertainty is available upon request

ABN 69336525019 A business unit of the South Australian Water Corporation GHD 180 Lonsdale Street Melbourne, Victoria 3000 T: (03) 8687 8000 F: (03) 8687 8111 E: [email protected]

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