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Developing Aquifer Storage and Recovery (ASR) Opportunities in Melbourne

Report on Broad Scale Map of ASR Potential for Melbourne

February 2006

Prepared with the support of:

Broad Scale Mapping

SINCLAIR KNIGHT MERZ PAGE i

Developing Aquifer Storage and Recovery (ASR) Opportunities in Melbourne

Report on Broad Scale Map of ASR Potential for Melbourne

Mike Dudding1, Richard Evans1, Peter Dillon2 and Robert Molloy2

1 Sinclair Knight Merz and 2 CSIRO Land and Water

Prepared for the Victorian Smart Water Fund

February 2006

Sinclair Knight Merz ABN 37 001 024 095 590 Orrong Road, Armadale 3143 PO Box 2500 Malvern VIC 3144 Australia Tel: +61 3 9248 3100 Fax: +61 3 9248 3364 Web: www.skmconsulting.com

© 2006 SKM. This work is copyright. It may be reproduced subject to the inclusion of an acknowledgement of the source.

SKM Reference WC02973: r01mwd_broad_scale_mapping_final.doc Important Disclaimer: SKM advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, SKM (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it.

Broad Scale Mapping

SINCLAIR KNIGHT MERZ PAGE i

Contents

Executive Summary 1

1. Introduction 1

2. Aquifer Location and Characteristics 1

3. Constraints to ASR 1 3.1 Operational Constraints 1 3.2 Losses to Surface Water 1 3.3 Groundwater Quality 1

4. ASR Capacity 1

5. Reliability of Broad Scale Map 1

6. Potential for ASR in Melbourne 1

7. Conclusions 1

8. Acknowledgements 1

9. References 1

Appendix A Surficial Geology, Provinces, and Geological Sections 1

Appendix B Depth to the Water Table 1

Appendix C Groundwater Beneficial Use 1

Appendix D ASR Capacity for Unconfined Aquifers 1

Appendix E ASR Capacity for Confined Aquifers 1

Appendix F ASR Storage Potential Maps (Broad Scale Maps) 1

Appendix G Details of Bore Yield and Geology at the Reliability Assessment Sites 1

Appendix H Broad Scale Maps with Reliability Assessment Sites 1

ASR Broad Scale Mapping

SINCLAIR KNIGHT MERZ PAGE ii

List of Figures Figure 1 Geological Provinces 1

Figure 2 Geological Section A-A’ 1

Figure 3 Geological Section B-B’ 1

Figure 4 Typical Thickness of Aquifers in the Study Area 1

Figure 5 Depth to Water Table Map 1

Figure 6 WTA Beneficial use Map 1

Figure 7 UTA Beneficial use Map 1

Figure 8 MTA Beneficial use Map 1

Figure 9 LTA Beneficial use Map 1

Figure 10 ASR capacity for the WTA 1

Figure 11 ASR capacity for the UTA 1

Figure 12 ASR capacity for the MTA 1

Figure 13 ASR capacity for the LTA 1

Figure 14 Highest ASR capacity for all aquifers 1

Figure 15 Highest ASR capacity for all aquifers excluding area of potable quality groundwater 1

Figure 16 Map of reliability assessment sites for the WTA 1

Figure 17 Map of reliability assessment sites for the UTA 1

Figure 18 Map of reliability assessment sites for the MTA 1

Figure 19 Map of reliability assessment sites for the LTA 1


SINCLAIR KNIGHT MERZ PAGE iii

List of Tables Table 1 Beneficial use segments 1

Table 2 Summary of aquifer characteristics for unconfined aquifers (after Leonard, 1992).1

Table 3 Summary of aquifer characteristics for confined aquifers (after Leonard, 1992). 1

Table 4 Maximum allowable impressed head for unconfined aquifers 1

Table 5 Estimated ASR capacity 1

Table 6 ASR capacity in each aquifer as a percentage of the Study area 1

Table 7 ASR capacity in each aquifer as a percentage of the metropolitan area 1

Table 8 Reliability assessment - bore yields compared to mapped storage potential 1

Table 9 Storage volume of aquifers with high or medium storage capacity 1

Table 10 Estimated storage volume of all aquifers in the Study area (GL) 1


SINCLAIR KNIGHT MERZ PAGE 1

Executive Summary To assist in identifying opportunities for aquifer storage and recovery (ASR) in the greater Melbourne metropolitan area a broad scale map showing the potential for ASR capacity was prepared using readily available hydrogeological data. Given the reliance upon interpolated data, the inherent complexity of geological structures, and knowledge gained from constructing bores, estimates of potential as mapped provide guidance only. This report explains the mapping process, the results produced and an indication of the reliability at selected sites.

The mapping suggests that up to a third of the study area is suitable for high or medium injection rate ASR projects, almost all of which occurs in the Lower Tertiary Aquifer. The total additional storage volume of aquifers in the 10,565 km2 Melbourne study area was calculated to be 2,800 GL (ie an average effective storage depth of 270mm water). However, only about 105 GL is considered to be accessible at rates that are economic. That is ASR, when fully developed, could provide irrigation quality water of up to about a quarter of Melbourne’s current total annual water demand. Of this capacity that is accessible at high and medium rates, approximately 90 GL is in the Lower Tertiary Aquifer and 15 GL is in the Water Table Aquifer. Most of the storage in the Lower Tertiary Aquifer is in the Western (60 GL) and Western Port Provinces (20 GL), with the balance being small but commercially viable storages in the Werribee Delta, South Eastern and Nepean Provinces.

The broad scale map was produced using interpreted data from sources that are of varying reliability and resolution. The map based data includes geology, depth to water table, and beneficial use which were intended for use at 1:250,000, 1:500,000 and 1:2,500,000 scales respectively. In general these maps are not adequate for site specific mapping because of their scales. However, as the objective was to identify the likely potential for ASR these sources of data were considered suitable.

To assess the maps’ reliability, borehole information on groundwater yield and hydro-stratigraphy (ie aquifer presence) was obtained from 31 sites at 25 locations across the area for comparison with the mapped storage potential. At 17 of the 31 sites, the borehole information matched the mapped category. At 8 sites the yields were higher than predicted, and at 6 sites the yields were lower than predicted. Overall, the reliability assessment revealed the map to be suitable as a guide to the ASR storage potential within the study area but, consistent with the broad brush nature of the input data, the map is not suitable as a substitute for site specific investigations.

Most of the storage zones contain brackish groundwater, which may explain the currently limited amount of hydrogeological information given the state of development of the area.



Brackish aquifers however make very suitable storage zones for environmental and economic reasons. While in some Provinces (Mornington and Bellarine) the predictions are for negligible accessible storage capacity, it must be remembered that the data supporting these predictions are sparse, and small scale storages may be possible in hydrogeological niches within any Province.



1. Introduction Aquifers are natural underground layers of rock or sand that water can percolate through. The technique referred to as aquifer storage and recovery (ASR) is a way of enhancing the recharge of groundwater. It involves collection or harvesting of surplus supplies of water, for example stormwater or recycled water; treating it, and then pumping this water via one or more wells into an aquifer, with subsequent extraction for reuse via the same wells. ASR is predominantly a means of storing water, but may also provide further water treatment as a result of the biogeochemical processes within the aquifer.

ASR presents an opportunity to provide winter storage for stormwater and recycled water, which could be extracted to meet peak demand in summer. Subsurface storage of stormwater or recycled water can create new water resources, especially for non-potable uses, and should be more cost effective than surface storages in urban areas.

In general, selection of an ASR site has four requirements:

1) A demand for water of the quality that can be recovered.

2) Access to a source of water, such as from a stormwater drain or recycled water pipeline.

3) Sufficient land available to build a detention storage and/or treatment plant.

4) An aquifer with suitable storage capacity and water quality, and allowing adequate rate of injection and capacity to recover stored waters.

This report, which focuses on the last requirement, presents the result of broad scale mapping of ASR potential for the Melbourne metropolitan area using readily available hydrogeological information.

The method for hydrogeological assessment in Melbourne was adopted having considered previous efforts to map ASR potential in Adelaide (Pavelic et al 1992, Hodgkin 2005) and Perth (Scatena and Williamson 1999), and taking into account the relatively reduced availability of suitable validated hydrogeological data in Melbourne.



2. Aquifer Location and Characteristics Characteristics of aquifers which favour ASR are as follows:

• High bore yields – which allow high injection and recovery rates so more water can be stored and recovered per bore.

• Brackish native groundwater – so that injection of treated storm water will only expand the range of beneficial uses of the aquifer (eg reduce the salinity to make recovered water fit for irrigation). However, excessively high native groundwater salinities will reduce the proportion of fresh water that can be recovered at a suitable quality.

• Low native hydraulic gradient – so that water can be stored locally and more easily recovered.

• High storage capacity – aquifers that are thick and/or have a high porosity.

• Aquifers with large grain size – to minimise the potential for clogging.

• Homogeneous aquifers – to maximise the volume of recoverable water.

• Non-leaky aquitards (in the case of confined aquifers) – to reduce the losses of water, minimise mixing with poorer quality water, and prevent problems that could occur through changing water table levels.

• Low initial piezometric pressures (in the case of confined aquifers) – to minimise energy costs of injection or allow for gravity drainage, and give opportunity for higher injection pressures without reaching aquitard bursting pressures.

• Deep water table (in the case of unconfined aquifers) – so that water table fluctuations caused by ASR do not adversely affect stream baseflow, groundwater dependent ecosystems, or foundations of buildings and structures.

• Unpolluted aquifers – are preferred so as not to mobilise contaminants within an aquifer

• Aquifers with compatible mineralogy or water quality – biogeochemical reactions between injected waters and native groundwaters can for some sites result in the mobilisation of constituents (eg arsenic) at concentrations that are unacceptable in recovered water. An initial geochemical evaluation will allow the potential for this to be assessed.

In general groundwater systems are divided into two main types – unconfined aquifers, and confined aquifers. Confined aquifers which are hydraulically isolated from surface infiltration by low permeability layers are preferred for ASR because there is less likelihood of pollution from other sources. Unconfined aquifers are also suitable for ASR but tend to have more complexities such as water logging and geochemical issues when water tables rise



(due to ASR) and approach the ground surface. However, where the water table is deep unconfined aquifers can provide useful storage for irrigation supplies.

The characteristics of both aquifer types are defined by their geology in terms of composition, thickness, and depth. The geology of Melbourne is divided into two distinct regions;

1 Northern region comprising bedrock (sandstones, siltstones and granites) of Devonian and Silurian age, and

2 Southern region comprising unconsolidated sediment and basalt of Cainozoic age.

The confined aquifers occur only in the southern region whereas the unconfined aquifers occur over the entire study area. The confined aquifers occur at various depths and are comprised predominantly of unconsolidated sediments that are formed into three distinct layers that are represented by three broad age groups with the oldest group being the deepest. From youngest to oldest these aquifers are as follows:

Upper Tertiary Aquifer (UTA) Middle Tertiary Aquifer (MTA) Lower Tertiary Aquifer (LTA)

The unconfined aquifers are exposed at the surface, and are present across the entire study area, and comprise three main geological types;

Basalt of Cainozoic age (ie Quaternary and Tertiary), Unconsolidated sediments of Cainozoic age, and Bedrock of Devonian and Silurian age

In different parts of the study area the hydraulic characteristics (ie transmissivity and storativity) of an aquifer may vary due to changes in thickness and lithological characteristics. Due to the absence of a hydrogeological map for the study area, a mapping technique was employed that assigns aquifer parameters to sub-regions or provinces that comprise similar characteristics. The aquifer parameters for each province were derived from a summary compiled by Leonard (1992). Leonard (1979) divided the Melbourne aquifers into six hydrogeological provinces, five for the Cainozoic Aquifers (ie the unconsolidated sediments and basalt) and one for the bedrock (Northern province). For this study an additional province has been added to enable the inclusion of the Western Port area. The seven provinces are as follows:

1 Western (including the Werribee Delta Province), 2 South Eastern,



3 Mornington, 4 Western Port. 5 Nepean, 6 Bellarine, and 7 North Eastern.

The location of the provinces and surficial geology are shown in Appendix A. The quality of groundwater present in each aquifer is categorised according to its beneficial use (definition of beneficial use is described in Table 1). The hydraulic characteristics of the unconfined and confined aquifers are shown in Table 2 and Table 3 respectively. The typical depth and thickness of aquifers in each province are shown in Appendix A.

The depth to the water table is shown in Appendix B (SKM, 1998). Due to the absence of piezometric maps for the confined aquifers, the piezometric head was assumed to be at the same elevation as ground surface.

Table 1 Beneficial use segments

Segments (mg/L TDS)

A1 0 - 500

A2 501 - 1,000

B 1,001 - 3,500

C 3,501 - 13,000

D greater

than 13,000

Beneficial Uses

1. Maintenance of Ecosystems 2. Potable Water Supply: desirable * acceptable * 3. Potable Mineral Water 4. Agriculture, Parks and Gardens 5. Stock Watering 6. Industrial Water Use 7. Primary Contact Recreation (eg.

bathing, swimming)

8. Buildings and Structures



Table 2 Summary of aquifer characteristics for unconfined aquifers (after Leonard, 1992).

Hydrogeological Province

Aquifer Age Group

Geological name Depth (m) Saturated Thickness (m)

Hydraulic conductivity (m/d)

Transmissivity (m2/d)

Specific Yield

Water level (m BGL)

Beneficial Use Category3

Western Quaternary Newer Volcanics 0 (outcropping) 10 – 100 1 – 6 1 – 100 UK (0.05 – 0.1)

5 – 50 C

Werribee Delta Quaternary Werribee Delta 0 (outcropping) 5 – 40 1 – 15 50 – 500 0.05 – 0.25 3 – 10 B

Middle Tertiary Fyansford Formation B

Upper Tertiary Brighton Group

0 - 101 50 – 851 0.4 25 – 50 0.1 0 – 30

A2, B

South Eastern

Quaternary Minor dune deposits 0 (outcropping) 5 – 10 UK UK (<50) 0.05 – 0.25 2 – 10 A1, A2, B, C

Werribee Fm 10 – 30 10 – 15 UK (~5 – 30) B Lower Tertiary

Older Volcanics 0 – 20 10 – 20 5 – 30 B

Middle Tertiary Fyansford Fm 0 – 20 10 – 15 5 – 30 B

Upper Tertiary Brighton Group 0 – 20 10 – 15 UK (~20) A2, B

Mornington West

Quaternary Minor Alluvium 0 (outcropping) 5 – 10

UK UK (<50) UK (~0.05)

UK (~5 – 30) A2, B, C

Childers Fm 20 – 30 0 – 20 B Lower Tertiary

Older Volcanics 10 – 30 10 – 50 B

Middle Tertiary Sherwood Fm 0 – 20 0 – 20 B

Mornington East

Upper Tertiary Baxter Fm 0 – 20 5 – 30

12 20 – 502 0.05 10 – 20

A2, B

Upper Tertiary Wannaeue Fm 100 - 150 50 – 100 UK UK (<200) UK (~0.05) UK (~0.5 – 10) UK (A2?) Nepean

Quaternary Bridgewater Fm 0 (outcropping) 100 – 150 5 – 30 500 – 3000 0.2 0.5 – 10 A2

Bellarine Upper Tertiary Moorabool Viaduct Fm 0 (outcropping) 15 – 30 UK UK (<50) UK (~0.05) UK (~5 – 10) B, C

North Eastern Paleozoic bedrock

Various granites, siltstones and sandstones

0 (outcropping) Not applicable 1 – 0.01 <100 0.1 - 0.01 1 – 20 A1, A2, B, C

1. The Fyansford Fm and Brighton Gp in this area are considered to behave as a combined aquifer system and, hence, are described as having the same characteristics 2. The aquifers of the Western Port basin are considered to be in good hydraulic connection and, hence, are treated as a single aquifer system. Data sourced from the

groundwater model developed for the Koo Wee Rup/Dalmore/Lang Lang Groundwater supply protection area (SKM, 2001), and Carillio-Rivera (1975).

3. Beneficial use categories A1 and A2 represent potable standard water. The other categories “B” and “C” are non-potable (refer to Table 1). 4. UK = “unknown”. Estimated values shown in brackets.



Table 3 Summary of aquifer characteristics for confined aquifers (after Leonard, 1992).

Hydrogeological Province

Aquifer Age Group

Geological name Depth (m) Saturated Thickness (m)

Hydraulic conductivity (m/d)

Transmissivity (m2/d)

Storage co-efficient

Water level (m BGL)

Beneficial Use Category2

Lower Tertiary Werribee Formation 20 – 150 50 – 150 3 – 15 150 – 2000 5x10-4 0 – 20 B, C Western and Werribee Delta Middle Tertiary Batesford Limestone 10 – 200 25 – 75 2 – 15 50 – 1000 UK (~5x10-4) UK (~5 – 20) B

Werribee Formation 40 – 90 10 – 40 5 50 – 200 UK (~5x10-4) 5 – 20 B South Eastern Lower Tertiary

Older Volcanics 40 – 90 5 – 45 UK (0.5 – 1) 25 – 450 2x10-3 5 – 20 B

Werribee Fm 300 - 900 50 – 150 UK UK (<2000) UK (~1x10-5) 5 – 10 C Nepean Lower Tertiary

Older Volcanics 350 - 1000 50 – 100 UK (~0.5 – 1) UK (<100) UK (~1x10-5) UK (~5 – 10) C

Childers Fm 50 - 200 20 – 70 A2, B Lower Tertiary

Older Volcanics 30 – 170 10 – 100 A2, B

Middle Tertiary Yallock Fm 50 -150 0 – 75 A2, B

Western Port

Upper Tertiary Baxter Fm 10 - 80 0 – 75

1 - 21 50 – 10001 1x10-3 1 - 5

A2, B, C 1 The aquifers of the Western Port basin are considered to be in good hydraulic connection and, hence, are treated as a single aquifer system. Data sourced from the

groundwater model developed for the Koo Wee Rup/Dalmore/Lang Lang Groundwater supply protection area (SKM, 2001), and Carillo-Rivera (1975).

2 Beneficial use categories A1 and A2 represent potable standard water. The other categories “B” and “C” are non-potable.

3 UK = “unknown”. Estimated values shown on brackets.



3. Constraints to ASR

3.1 Operational Constraints The operational limitations on an injection well relate to aquifer characteristics and the quality and quantity of water available for recharge. Throughout this report it is assumed that suitable treatment methods will be applied so that clogging does not become a constraint on the recharge potential. It is also assumed that the volume of water available for recharge is sufficient to freshen enough aquifer volume that an adequate proportion of the injected water can be recovered at a quality fit for use.

The key limitations for an injection well are the maximum allowable impressed head, well efficiency, period of operation, and velocity across the well screen. For unconfined aquifers the maximum allowable impressed head is the depth to the water table. The depth to water table data used in this assessment is provided in five categories, and is derived from the groundwater risk mapping project for Victoria (SKM, 1998. Table 4). To take into account fluctuating groundwater levels the shallowest water table depth in each category was used to define the maximum allowable impressed head. In addition, in calculating storage potential in unconfined aquifers (Appendix D) it was assumed that an injection bore would operate with a well efficiency of 80%, which further reduces the maximum allowable impressed head (Table 4). For short operational periods the maximum impressed head provides an upper limit on the rate of injection, whereas longer injection periods are more suitable for evaluating the volume that can be injected. For the purposes of this study a continuous operational period of 180 days was adopted. The 180 day period was adopted as an upper estimate of the number of days when stormwater is available for injection over a 12 month period1.

For confined aquifers a greater level of impressed head may be used up to an approximate maximum of 1.5 times the depth to the top of the aquifer plus the depth to the pre-injection (ie ambient) piezometric surface. However, as the total head increases so do the costs of injection as do the risks of losses to the surface or other aquifers. As a result an upper limit of 50 m above ground level was used to constrain the impressed head to estimate storage potential in confined aquifers (Appendix E). For water supply bores the upper limit for the entry velocity is usually restricted to 0.03 m/sec in order to minimise well losses, corrosion, and abrasion. However, a factor of safety is normally applied which reduces the design entry velocity to 0.015m/sec (Driscoll, 1986). With a typical injection bore diameter of 200 mm and a screen open area of 35% the aquifer would need to be less than 10 m thick and the

1 This also allows for non-injection periods to enable maintenance of the injection bore and/or pump.



injection rate greater than 1.5 ML/day before the entry velocity would exceed 0.015 m/sec. With most aquifers having a thickness significantly greater than 10 m it is highly unlikely that the entry velocity across the injection bore screen will be a constraint to the ASR potential.

Table 4 Maximum allowable impressed head for unconfined aquifers

Water table depth (m) Max. allowable impressed head (m) – 100% well efficiency

Impressed head (m) used to calculate storage potential– 80% well efficiency

0 to 2 water table too shallow for injection water table too shallow for injection 2 to 5 not recommended for injection not recommended for injection 5 to 10 5 4 10 to 20 10 8 >20 20* 16

* maximum head limited to 20 m due to the low reliability of the depth to water table map (ie conservative approach taken).

3.2 Losses to Surface Water Unconfined aquifers are typically in direct connection with surface water features such as streams and wetlands. As a consequence there is significant potential for injected water to discharge into surface water systems and, hence, not be recoverable. To prevent such losses injection sites are generally not located adjacent to surface water systems. An exception to this are ASR systems that are intended to provide an environmental benefit to wetlands and streams where some of the injected water is intended to be lost to surface water. The closest an injection site should be located to a surface water features (to avoid losses) is dependent on a wide range of factors such as the aquifer hydraulic characteristics, the groundwater gradient, the volume of water injected and the duration of storage. It is beyond the scope of the broad scale mapping to compile all of this information and calculate the minimum distance around every surface water feature in the study area. For this component of the study a 200 m zone around all surface water bodies was adopted as having a high potential for losses and, hence, not suitable for ASR in unconfined aquifers.

3.3 Groundwater Quality Using non-potable aquifers for ASR is preferable to using potable aquifers due to the lower level of groundwater quality protection and water treatment that is likely to be required (Dillon and Molloy, 2006). In this study areas of potable quality groundwater have been included in the maps of ASR potential. These areas have been identified so they can be avoided if required. The location of potable groundwater was identified using the groundwater beneficial use maps for Victoria which were intended for use at a scale of 1:500,000 or smaller (eg 1:1,000,000) (DCNR, 1995, Appendix C).



4. ASR Capacity Aquifer properties in conjunction with the operational constraints were used to derive the potential annual injection capacity of a single well in four categories ranging from very low to high (Table 5). Even a site with very low ASR capacity may be adequate for small scale operations. However, larger scale operations are much more likely to be economically attractive, and as indicated by Dillon and Pavelic (1996) this provides incentive for maintenance and environmental safeguards for ASR operations. Marginally economic operations should be discouraged.

The ASR capacity represents the volume of water that could be injected through a single bore that fully penetrates the aquifer and is operated continuously for 180 days. The volume that could be injected into a bore was calculated using the Theis solution to transient groundwater flow. The results are tabulated in Appendix D and Appendix E for unconfined and confined aquifers respectively. The distribution of ASR capacity across the study area has been mapped for unconfined, and confined upper, middle and lower tertiary aquifers showing the best potential for the aquifer present (Appendix F, Figures 10-13). The best capacity regardless of aquifer has also been mapped (Appendix F, Figure 14) and also excluding areas where groundwater is potable (Appendix F, Figure 15).

Due to the relatively cursory nature of the input data for the mapping exercise a conservative approach was taken for the calculation of recharge capacity. This was done by using the lowest value of transmissivity and the lowest value of storativity within the potential range of values identified in Table 2 and Table 3. The shallowest water table depth was also used rather than the average. The initial (ie pre-injection) groundwater levels were obtained from the depth to water table map for unconfined aquifers (SKM, 1998, Appendix B). Due to the absence of piezometric maps for the confined aquifers, the piezometric head was assumed to be at the same elevation as ground surface.

The mapping exercise revealed that based on hydrogeological information up to 85% of the study area and up to 83% of the metropolitan area had storage capacity for injected water. And of this area, up to 33% of the study area and up to 25% of the metropolitan area is suitable for high or medium capacity ASR projects, almost all of which occurs in the Lower Tertiary Aquifer (Table 6 and Table 7). The map for unconfined aquifers (Figure 10) also shows that 15% of the study area and 17% of the metropolitan area is unsuitable for ASR due to the very shallow water table in areas such as the Yarra Delta, Carrum-Edithvale, Altona-Point Cook, and the Western Treatment Plant, and the presence of zones where high losses may occur within 100 m of streams and rivers (Table 6 and Table 7).



With the use of multiple injection wells it may be possible to increase the ASR capacity to a category greater than that shown on the composite map (Figure 14). However, given the cost implications associated with drilling multiple injection wells this approach is likely to increase the capacity by only one category (eg from low to medium, not low to high).

Table 5 Estimated ASR capacity

Category Average Injection Rate Annual Injection Volume (ML)

Potential Water Supply

High >1 ML/day (>11.6 L/sec) >180 Moderate size stormwater catchments, detention pond and treatment plant or sewer trunk main and treatment plant

Medium >0.5 <1 ML/day (>5.8 <11.6 L/sec)

90 – 180 Small size stormwater catchments, detention pond and treatment plant or sewer main and treatment plant

Low >0.1 <0.5 ML/day (>1.2 <5.8 L/sec)

18 – 90 Rain water or storm water from small housing, commercial or industrial developments with detention storage and treatment

Very Low <0.1 ML/day (<1.2 L/sec) <18 Rain water from individual houses or cluster developments

Table 6 ASR capacity in each aquifer as a percentage of the Study area

ASR Storage Potential Water Table Aquifer

Upper Tertiary Aquifer

Mid Tertiary Aquifer

Lower Tertiary Aquifer

High 1% - - 24% Medium 1% 8% 11% 1% Low 24% - - - Very low 58% 21% - 1% Not suitable (shallow water table) 1% N/A N/A N/A Not suitable (high loss zone within 100m of a stream)

15% N/A N/A N/A

Table 7 ASR capacity in each aquifer as a percentage of the metropolitan area

ASR Storage Potential Water Table Aquifer

Upper Tertiary Aquifer

Mid Tertiary Aquifer

Lower Tertiary Aquifer

High 1% - - 22% Medium 1% - - 3% Low 26% - - - Very low 55% 26% - - Not suitable (shallow water table) 2% N/A N/A N/A Not suitable (high loss zone within 100m of a stream)

15% N/A N/A N/A



5. Reliability of Broad Scale Map The broad scale map has been produced using interpreted data from sources that are of varying reliability and resolution. The water table depths, groundwater salinity, and aquifer extent data were derived from existing maps which were intended for purposes unrelated to the this project. The map based data includes geology, depth to water table, and beneficial use which were intended for use at 1:250,000, 1:500,000, and 1:2,500,000 scales respectively.

In general these maps are not adequate for a detailed mapping exercise because of their scales. However, as the Broad Scale Map was intended to identify the likely potential for ASR and to focus further investigations on the most prospective areas, they were considered applicable for this project. The ASR potential broad scale map is not a substitute for local field investigations that are required to validate the ASR potential at a specific site.

The other key data used to produce the Broad Scale Map were aquifer parameters such as hydraulic conductivity and storage co-efficient that are poorly described for the Melbourne area and are not available in a map form. In order to assign aquifer parameters to the various aquifers in the Melbourne area a simple mapping exercise was undertaken where the region was divided into hydrogeological provinces to which specific aquifer parameters were assigned (this is described in Section 2 of this report).

As a result of combining these data sources the reliability of the Broad Scale Map is not self-evident. In order to obtain some understanding of the Broad Scale Maps reliability, borehole information on groundwater yield and hydro-stratigraphy (ie aquifer presence) was obtained from 31 sites at 25 locations across the project area. Bore yield data was obtained from the state groundwater database (GMS) and from pumping tests undertaken in the study area. The data obtained for these reliability assessment sites were then compared to the storage potential as shown on relevant Broad Scale Maps (Appendix F). Details are shown in Appendix G.

The results show that bore yields at 17 of the 31 sites for reliability assessment matched the categories predicted from the broad scale map. At 8 sites the yields were higher than predicted and at 6 sites the yields were lower than predicted. At two sites where no aquifer was predicted, drilling and pumping found medium (in the UTA) and high (in the LTA) yield. At one site where the LTA was predicted to have high yield the aquifer was absent.

These results show that the Broad Scale Maps are suitable only as a guide to the ASR storage potential within the study area, and are not suitable for site specific investigations. The locations of the sites used for the map reliability assessment are shown in Appendix H.



Relatively few bores reach the most prospective aquifer, the LTA, primarily because this aquifer contains saline groundwater (ie saline aquifers tend to have less bore data because they are not suitable for water supply) and, hence, the limited number of sites available to confirm the reliability of aquifers categorised as having a high ASR potential.

Table 8 Reliability assessment - bore yields compared to mapped storage potential

Broad Scale Map ASR Capacity based on Bore Yield

ASR Capacity Aquifer Very Low Low Medium High

No. Sites per

category

WTA 11 2 1 0 14

UTA 1 1 1 0 3

MTA 0 0 1 0 1

LTA 0 0 0 1 1

Very low

all 12 3 3 1 19

WTA 2 3 0 0 5

UTA 0 0 0 0 0

MTA 0 0 0 0 0

LTA 0 0 0 0 0

Low

all 2 3 0 0 5

WTA 0 0 0 0 0

UTA 0 0 0 0 0

MTA 0 0 0 0 0

LTA 1 1 1 1 4

Medium

all 1 1 1 1 4

WTA 0 0 0 0 0

UTA 0 0 0 0 0 MTA 0 0 0 0 0

LTA 1 0 1 1 3

High

all 1 0 1 1 3

All categories 16 7 5 3 31



6. Potential for ASR in Melbourne The maps of ASR capacity presented in Appendix F represent the likely yield of individual ASR wells given the constraints and assumed operating conditions previously described. In addition to the yield for an individual ASR bore these maps, together with information in Appendix E can be used to determine the gross storage volume available for ASR within each aquifer. The analysis so far has focussed on the rates of injection and recovery but, in this section, is extended to determine the volume of annual storage and recovery possible from the four aquifer systems present in the study area.

Table 9 summarises the area of each hydrogeological province which has medium to high capacity for ASR. This was derived from Table 10 which shows the area of each high, medium, low and very low region for each aquifer. Making use of the allowable impressed data (Table 4) and storage co-efficient of 0.05 for unconfined aquifers (Table 2), and an assumed impressed head of 50 m and storage co-efficient of 5 x 10-4 for confined aquifers the annual storage volume can be estimated. From Table 10 it can be seen that the total annual storage volume for the mapped region is approximately 2,800GL/year.

While there is apparently large available storage volume in the unconfined aquifer due to the low yields of most wells, this volume can only be tapped by small scale ASR projects which at best are likely to be marginally economic with current construction and operating costs. The aquifer with the greatest potential for large scale ASR is the LTA in the Western (including the Werribee Delta), Western Port, and South Eastern provinces (Table 9). Clearly these results contain uncertainties that will only be resolved through improved understanding of deeper aquifer systems (the LTA in particular) and through the operation of demonstration projects.

The estimated total additional storage volume of aquifers in the Melbourne study area of 10,565km2 is 2,800GL (at an average effective storage depth of 270mm water). For the purposes of scale this volume is greater than Melbourne’s surface water storages and is between 5 and 6 years the total mains water demand. However, of that total storage volume, all but about 150GL is in the Water Table Aquifer and over much of the area this is considered as having low permeability or the water table is too close to the surface or too near streams where stored water would discharge, to be considered a viable ASR storage zone. However, about 105GL storage is considered to be accessible at rates that are economic. That is ASR, when fully developed, could only provide up to approximately 23% of Melbourne’s current annual water demand. Of this volume that is accessible at high and medium rates, approximately 90GL is in the Lower Tertiary Aquifer and 15GL is in the Water Table Aquifer. Most of the storage in the Lower Tertiary Aquifer is in the Western



(64GL) and Western Port Provinces (18GL), with the balance being small but commercially viable storages in the Werribee Delta, South Eastern and Nepean Provinces.

Up to about a third of the study area is suitable for high or medium rate ASR projects in the Lower Tertiary Aquifer. The Nepean Province is the only one with substantial accessible storage capacity in the Water Table Aquifer.

Most of the storage zones contain brackish groundwater, which may explain the currently limited amount of hydrogeological information given the state of development of the area. Brackish aquifers however make very suitable storage zones for ASR based on both environmental and economic reasons. While in some Provinces (Mornington and Bellarine) the predictions are for negligible accessible storage capacity, it must be remembered that the data supporting these predictions are sparse, and small scale storages may be possible in hydrogeological niches within any Province.

Table 9 Storage volume of aquifers with high or medium storage capacity

Province Area with High or Medium injection capacity (km2)

Percentage of province area with high or medium injection capcity

Storage Volume (GL)

Dominant aquifer for Storage

Western 2,553 70% 64 LTA

Werribee Delta 145 100% 4 LTA

Southeastern 127 35% 3 LTA

Mornington 0 0% 0 N/A

Western Port 710 70% 18 LTA

Nepean 108 100% 18 WTA

Bellarine 0 0% 0 N/A

Northeastern 0 0% 0 N/A

all provinces 3,643 34% 106 N/A

Broad Scale Mapping

PAGE 17

Table 10 Estimated storage volume of all aquifers in the Study area (GL)

Province Mapped ASR Injection Capacity Water Table Aquifer Confined Aquifers All Aquifers Area

(km2) Avg Water Table

Depth (m) Avg available

impressed head (m) Volume1

(GL) UTA (km2)

MTA (km2)

LTA (km2)

Volume (GL) Total Volume (GL)

High 0 N/A 0 0 0 0 2,188 55 55

Medium 0 N/A 0 0 0 365 0 9 9

Low 907 17 13.6 617 0 0 0 0 617

Very Low 1,973 7 5.6 553 2,429 0 0 61 613

Unsuitable - water table 0-2m BGL 34 - - - - - - - -

Unsuitable - within 100m of water course 720 - - - - - - - -

Western

Total 3,647 - - 1,169 125 1,294

High 0 0 0 0 0 0 145 4 4

Medium 0 0 0 0 0 0 0 0 0

Low 43 6 4.8 10 0 0 0 0 10

Very Low 33 2 1.6 3 0 0 0 0 3



Werribee Delta

Total 145 - - 13 4 17

High 0 0 0 0 0 0 18 0 0

Medium 0 0 0 0 0 0 109 3 3

Low 6 10 8.0 2 0 0 0 0 2

Very Low 277 3 2.4 33 0 0 0 0 33



Southeastern

Total 364 36 3 39

High 0 0 0 0 0 0 0 0 0

Medium 0 0 0 0 0 0 0 0 0

Low 78 12 9.6 38 0 0 0 0 38

Very Low 754 5 4.0 151 0 0 0 0 151



Mornington

Total 1,122 - - 188 0 188

1. calculated assuming a specific yield of 0.05 for unconfined aquifers and a storage coefficient of 5 x 10-4 for confined aquifers



Province Mapped ASR Injection Capacity Water Table Aquifer Confined Aquifers All Aquifers Area

(km2) Avg Water Table

Depth (m) Avg available

impressed head (m) Volume1

(GL) UTA (km2)

MTA (km2)

LTA (km2)

Volume (GL) Total Volume (GL)

High 0 0 0 0 02 02 7102 182 18

Medium 0 0 0 0 0 0 0 0 0

Low 4 19 15.2 3 0 0 0 0 3

Very Low 871 3 2.6 115 0 0 0 0 115



Western Port

Total 1,014 - - 118 18 136

High 62 5 4.0 12 0 0 108 3 15

Medium 32 2 1.6 3 0 0 0 0 3

Low 0.01 10 8.0 0.003 0 0 0 0 0

Very Low 0.14 4 3.2 0.022 0 0 0 0 0



Nepean

Total 108 15 3 18

High 0 0 0 0 0 0 0 0 0

Medium 0 0 0 0 0 0 0 0 0

Low 40 7 5.6 11 0 0 0 0 11

Very Low 354 2 1.6 28 0 0 0 0 28



Bellarine

Total 559 - - 39 0 39

High 0 N/A 0 0 0 0 0 5 0

Medium 0 N/A 0 0 0 0 0 27 0

Low 1,676 13 10.7 899 0 0 0 0 899

Very Low 972 5 4.0 194 0 0 0 0 194



Northeastern

Total 3,606 - - 1,093 32 1,093

Total High Potential all provinces 12 79 91

Total Medium Potential all provinces 3 12 15

Total High & Medium Potential all provinces 15 91 106

Total all provinces 10,565 - - 2,672 152 2,824

1. calculated assuming a specific yield of 0.05 for unconfined aquifers and a storage coefficient of 5 x 10-4 for confined aquifers 2. to avoid double accounting where the tertiary aquifers are interconnected, the storage volume has been assigned to the LTA



7. Conclusions The data collected during this project suggests that although there is a substantial storage volume available in Melbourne’s aquifers (2,800GL), most of this is not suitable for economic ASR. However, about 105GL is considered to be accessible at rates that are economic. That is ASR, when fully developed, could provide up to approximately 23% of Melbourne’s current annual water demand. Of this capacity that is accessible at high and medium rates, approximately 91 GL is in the Lower Tertiary Aquifer and 15GL is in the Water Table Aquifer. Most of the storage in the Lower Tertiary Aquifer is in the Western (64GL) and Western Port Provinces (18GL), with the balance being small but commercially viable storages in the Werribee Delta, South Eastern and Nepean Provinces.

Approximately a third of the study area and up to a quarter of the metropolitan area is suitable for high or medium injection rate ASR projects, almost all of which occurs in the Lower Tertiary Aquifer. The Nepean Province is the only one with substantial accessible storage capacity in the Water Table Aquifer.

Most of the storage zones contain brackish groundwater, which may explain the currently limited amount of hydrogeological information given the state of development of the study area. Brackish aquifers however make very suitable storage zones for environmental and economic reasons.

While in some Provinces (Mornington and Bellarine) the predictions are for negligible accessible storage capacity, it must be remembered that the data supporting these predictions are sparse, and small scale storages could be possible in hydrogeological niches within any Province.

It should be noted that the confined aquifer in the Nepean province is less suitable for ASR due to it being located more than 400 m below ground surface (ie there is a very high cost to drill to this depth). The map also shows that 15% of the study area is unsuitable for ASR due to the very shallow water table in areas such as the Yarra Delta, Carrum-Edithvale, Altona-Point Cook, and the Western Treatment Plant, and the presence of zones where high losses may occur within 100m of streams and rivers.

With the use of multiple injection wells it may be possible to increase the ASR storage potential to a category greater than that shown on the final map. However, given the cost implications associated with drilling multiple injection wells this approach could only be used to increase the storage potential by one category (eg from low to medium, not low to high).

Due to the relatively low resolution of the hydrogeological data used to evaluate ASR capacity, an assessment of the broad scale map reliability was undertaken. The results show that bore yields at 17 of 31 sites used for the reliability assessment matched the categories predicted from the broad



scale map. At 8 sites the yields were higher than predicted and at 6 sites the yields were lower than predicted. At two sites where no aquifer was predicted, drilling and pumping found low (in the UTA) and high (in the LTA) yield. At one site where the LTA was predicted to have high yield the aquifer was absent. These results show that the Broad Scale Map is suitable only as a guide to the ASR storage potential within the study area, and is not suitable for site specific investigations.



8. Acknowledgements This report on the broad scale map of ASR potential in Melbourne was developed with the financial support of the Victorian Smart Water Fund, which encourages innovation in water conservation and recycling to help secure the state’s water future. The Fund recognises that effective aquifer storage and recovery (ASR) has a role to play in sustainable management of water resources and the environment.

The authors gratefully acknowledge members of the project steering committee for their helpful comments on drafts of this report.

Project Steering Committee:

Simon Lees, Smart Water Fund

Richard Clarke, South East Water Limited

Terry Flynn, Southern Rural Water

Deborah Cownley and Gordon McFarlane, Melbourne Water Corporation

Randall Nott, Department of Sustainability and Environment

Michael Rehfisch, EPA

Suzie Sarkis, Department of Human Services

Matthew Inman (replaced Grace Mitchell), CSIRO Water for Healthy Country Flagship

Peter Dillon and Robert Molloy, CSIRO Land and Water

Richard Evans, Sinclair Knight Merz

And finally the Spatial Division of SKM is thanked for their assistance in producing the maps published in this report.



9. References Carillo-Rivera, J. J. (1975) Hydrogeology of Western Port. Rept. Geol. Surv. Vict. 1975/1.

DCNR (1995) Victorian Groundwater Beneficial Use Map Series.

Dillon, P.J. and Molloy R.P. (2006) Technical Guidance for ASR. Smart Water Fund Project – Developing aquifer storage and recovery (ASR) opportunities in Melbourne, CSIRO.

Dillon, P.J. and Pavelic, P. (1996) Guidelines on the quality of stormwater and treated wastewater for injection into aquifers for storage and reuse. Urban Water Research Association of Australia Research Report No. 109.

Dillon, P., Pavelic, P., Evans, R. and Williams, M. (2004). Characterising Sites for Water Banks. Edgeworth David Society and The Earth Resources Foundation, School of Geosciences, University of Sydney, 17th Annual Symposium “Characterising subsurface storage sites” 3 September 2004, The University of Sydney.

Driscoll, F. G. (1986). Groundwater and Wells. Second edition. Published by U.S. Filter/Johnson Screens. ISBN 0-9616456-0-1.

Hodgkin, T. (2005). Aquifer storage capacities of the Adelaide region. South Australia Department of Water, Land and Biodiversity Conservation Report 2004/47.

Leonard, J. G. (1992). Port Phillip Region Groundwater Resources – Future use and Management. Department of Water Resources, Victoria. ISBN 0 7306 26898 X.

Pavelic, P., Gerges, N.Z., Dillon, P.J. and Armstrong, D. (1992). The potential for storage and reuse of Adelaide's stormwater runoff using the Upper Quaternary groundwater system. Centre for Groundwater Studies Report No. 40.

Scatena, M.C. and Williamson, D.R. (1999). A potential role for artificial recharge within the Perth Region: a pre-feasibility study. Centre for Groundwater Studies Report No 84.

SKM (1998). Metadata Descriptions for Data Sets used in the Preparation of Groundwater Risk Maps. SKM reference R01ghmmdata.doc.

SKM (2001). Koo Wee Rup / Dalmore and Lang Lang Groundwater Supply Protection Area. SKM reference WC01759:WPB modelling report.doc

Broad Scale Mapping


Appendix A Surficial Geology, Provinces, and Geological Sections Figure 1 Geological Provinces



Figure 2 Geological Section A-A’



Figure 3 Geological Section B-B’



Figure 4 Typical Thickness of Aquifers in the Study Area (after Leonard, 1992)



Appendix B Depth to the Water Table Figure 5 Depth to Water Table Map



Appendix C Groundwater Beneficial Use Figure 6 WTA Beneficial use Map



Figure 7 UTA Beneficial use Map



Figure 8 MTA Beneficial use Map



Figure 9 LTA Beneficial use Map



Appendix D ASR Capacity for Unconfined Aquifers

Geological Type1 Province2 Age1 Geological Unit1 Water table depth (m)3 Max impressed head (m) Injection rate L/sec (after 180 days) storage potential

Basalt Western Quaternary Newer Volcanics 0-2 0 0 Water table too shallow

Basalt Western Quaternary Newer Volcanics 2-5 1.6 0 Very low

Basalt Western Quaternary Newer Volcanics 5-10 4 0.45 Very low

Basalt Western Quaternary Newer Volcanics 10-20 8 0.7 Very low

Basalt Western Quaternary Newer Volcanics 20-50 16 1.4 Low

Unconsolidated sediments Western Quaternary Alluvium 0-2 0 0 Water table too shallow

Unconsolidated sediments Western Quaternary Alluvium 2-5 1.6 0.15 Very low

Unconsolidated sediments Western Quaternary Alluvium 5-10 4 0.45 Low

Unconsolidated sediments Western Quaternary Alluvium 10-20 8 0.7 Low

Unconsolidated sediments Western Tertiary Fyansford Fm and Brighton Gp 0-2 0 0 Water table too shallow

Unconsolidated sediments Western Tertiary Fyansford Fm and Brighton Gp 2-5 1.6 0.15 Very low

Unconsolidated sediments Western Tertiary Fyansford Fm and Brighton Gp 5-10 4 0.45 Very low

Unconsolidated sediments Western Tertiary Werribee Fm 0-2 0 0 Water table too shallow

Unconsolidated sediments Western Tertiary Werribee Fm 2-5 1.6 2 Low

Unconsolidated sediments Western Tertiary Werribee Fm 5-10 4 4 Low

Unconsolidated sediments Western Tertiary Werribee Fm 10-20 8 12.5 Medium

Unconsolidated sediments Western Quaternary Werribee Delta 0-2 16 0 Water table too shallow

Unconsolidated sediments Western Quaternary Werribee Delta 2-5 1.6 0.7 Very low

Unconsolidated sediments Western Quaternary Werribee Delta 5-10 4 1.7 Low

Unconsolidated sediments Western Quaternary Werribee Delta 10-20 8 3.3 Low

Unconsolidated sediments South Eastern Quaternary Alluvium 0-2 16 0 Water table too shallow

Unconsolidated sediments South Eastern Quaternary Alluvium 2-5 1.6 0.43 Very low

Unconsolidated sediments South Eastern Quaternary Alluvium 5-10 4 0.9 Very low

Unconsolidated sediments South Eastern Tertiary Fyansford Fm and Brighton Gp 0-2 0 0 Water table too shallow

Unconsolidated sediments South Eastern Tertiary Fyansford Fm and Brighton Gp 2-5 1.6 0.43 Very low

Unconsolidated sediments South Eastern Tertiary Fyansford Fm and Brighton Gp 5-10 4 0.9 Very low

Unconsolidated sediments Mornington Quaternary Alluvium 0-2 0 0 Water table too shallow

Unconsolidated sediments Mornington Quaternary Alluvium 2-5 1.6 0.35 Very low

Unconsolidated sediments Mornington Quaternary Alluvium 5-10 4 0.7 Very low

Unconsolidated sediments Mornington Quaternary Alluvium 10-20 8 1.4 Low

Unconsolidated sediments Mornington Quaternary Alluvium 20-50 16 2.8 Low

Basalt Mornington Quaternary Older Volcanics 0-2 0 0 Water table too shallow

Basalt Mornington Quaternary Older Volcanics 2-5 1.6 0 Very low

Basalt Mornington Quaternary Older Volcanics 5-10 4 0.45 Very low

Basalt Mornington Quaternary Older Volcanics 10-20 8 0.7 Very low

Unconsolidated sediments Mornington Tertiary Werribee Fm, Fyansford Fm, Brighton Gp, Childers Fm, Sherwood Fm

0-2 0 0 Water table too shallow

Unconsolidated sediments Mornington Tertiary Werribee Fm, Fyansford Fm, Brighton Gp, Childers Fm, Sherwood Fm

2-5 1.6 0.35 Very low

Unconsolidated sediments Mornington Tertiary Werribee Fm, Fyansford Fm, Brighton Gp, Childers Fm, Sherwood Fm, Minor Alluvium

5-10 4 0.7 Very low


10-20 8 1.4 Low


20-50 16 2.8 Low



Geological Type1 Province2 Age1 Geological Unit1 Water table depth (m)3 Max impressed head (m) Injection rate L/sec (after 180 days) storage potential

Unconsolidated sediments Nepean Quaternary Bridgewater Fm 0-2 0 0 Water table too shallow

Unconsolidated sediments Nepean Quaternary Bridgewater Fm 2-5 1.6 8 Medium

Unconsolidated sediments Nepean Quaternary Bridgewater Fm 5-10 4 16 High

Unconsolidated sediments Bellarine Quaternary Alluvium 0-2 0 0 Water table too shallow

Unconsolidated sediments Bellarine Quaternary Alluvium 2-5 1.6 0.7 Very low

Unconsolidated sediments Bellarine Quaternary Alluvium 5-10 4 1.7 Low

Unconsolidated sediments Bellarine Tertiary Moorabool Viaduct Fm 0-2 0 0 Water table too shallow

Unconsolidated sediments Bellarine Tertiary Moorabool Viaduct Fm 2-5 1.6 0.7 Very low

Unconsolidated sediments Bellarine Tertiary Moorabool Viaduct Fm 5-10 4 1.7 Low

Unconsolidated sediments Western Port Quaternary Alluvium 0-2 0 0 Water table too shallow

Unconsolidated sediments Western Port Quaternary Alluvium 2-5 1.6 0.1 Very low

Unconsolidated sediments Western Port Quaternary Alluvium 5-10 4 0.2 Very low

Unconsolidated sediments Western Port Tertiary Werribee Fm, Fyansford Fm, Brighton Gp, Childers Fm, Sherwood Fm, Minor Alluvium

0-2 0 0 Water table too shallow


2-5 1.6 0.35 Very low


5-10 4 0.7 Very low

Basalt Western Port Tertiary Older Volcanics 0-2 0 0 Water table too shallow

Basalt Western Port Tertiary Older Volcanics 2-5 1.6 0 Very low

Basalt Western Port Tertiary Older Volcanics 5-10 4 0.45 Very low

Basalt Western Port Tertiary Older Volcanics 10-20 8 0.7 Very low

Bedrock All provinces Paleozoic bedrock Various granites, siltstones and sandstones 0-2 0 0 Water table too shallow

Bedrock All provinces Paleozoic bedrock Various granites, siltstones and sandstones 2-5 1.6 0.35 Very low

Bedrock All provinces Paleozoic bedrock Various granites, siltstones and sandstones 5-10 4 0.9 Very low

Bedrock All provinces Paleozoic bedrock Various granites, siltstones and sandstones 10-20 8 1.7 Low

Bedrock All provinces Paleozoic bedrock Various granites, siltstones and sandstones 20-50 16 3.5 Low 1. Data from the 1:250,000 scale geology map sheets for Melbourne, Queenscliff, and Warburton 2. As defined in Leonard (1992)

3. Derived from SKM (1998)



Appendix E ASR Capacity for Confined Aquifers

Aquifer1 Province2 Geological formation1 Maximum impressed head (m)3

Injection rate L/sec (after 180 days)

Storage potential

Lower Tertiary Western Werribee Formation 50 37 High

Lower Tertiary South Eastern Werribee Formation 50 16 Medium

Lower Tertiary Nepean Werribee Fm 50 500 High

Lower Tertiary Western Port Childers Fm 50 7 Medium

Lower Tertiary Bellarine Werribee Fm 50 0.2 Very low

Middle Tertiary Western Batesford Limestone 50 6.5 Medium

Middle Tertiary Western Port Yallock Fm 50 7 Medium

Upper Tertiary Western Brighton Gp 50 0.2 Very low

Upper Tertiary Western Port Baxter Fm 50 7 Medium

1 Data from the 1:250,000 scale geology map sheets for Melbourne, Queenscliff, and Warburton 2 As defined in Leonard (1992) 3 Assumed to be 50 m above ground surface 4 Due to the variable nature of this province and its location near the margins of the sedimentary basin it was downgraded from “high” to “medium”



Appendix F ASR Storage Potential Maps (Broad Scale Maps) Figure 10 ASR capacity for the WTA



Figure 11 ASR capacity for the UTA



Figure 12 ASR capacity for the MTA



Figure 13 ASR capacity for the LTA



Figure 14 Highest ASR capacity for all aquifers



Figure 15 Highest ASR capacity for all aquifers excluding area of potable quality groundwater



Appendix G Details of Bore Yield and Geology at the Reliability Assessment Sites Comparison of yield estimates at specific sites to Broad Scale Map

Site Location No. (as shown on maps in Appendix H

Site assessment No.

Name Distance to nearest bore with log (m)

Geology Aquifer present at site

Aquifers shown on broad scale map

ASR Storage capacity on broad scale map

ASR storage category based on yield estimate

Yield estimate (L/sec) Number of bores with yield estimates

1 1 Calder Park Industrial Estate 2415 63 m basalt, bedrock not struck WTA WTA Low Low 0.1 - 29 (median = 3.8) 5

2 WTA WTA Low very low 0.6 1 2

3 Melbourne Airport 733

16 m basalt, 13m fine sand and gravel, 3m basalt then bedrock

UTA UTA Very low very low 0.2 - 3.8 (median = 0.5) 5

4 WTA WTA Very low medium 0.3 -10.0 (median = 5) 10 3

5 City West Water & Excel Recycling 860 34 m basalt, 4 m sandy clay, then bedrock

not present LTA High very low aquifer absent -

6 WTA WTA Very low low 1.9 (median = 1.9) 3 4

7 Pipemakers Park 1440

21 m basalt, 4 m sand, 5 m clayey sand, bedrock not struck

MTA MTA Very low medium 0.8 - 2.5 (median = 2.5) 4

5 8 Northern Memorial Park 477 14m clay, then bedrock WTA WTA Very low very low 0.4 - 4.0 (median = 0.4) 6

6 9 Craigieburn Public Golf Course 1233 bedrock at surface WTA WTA Very low very low 0.1 - 2.3 (median = 0.9) 7

7 10 Lilydale Works Depot 2795 bedrock at surface WTA WTA Low low 0.4 - 1.9 (median = 1.5) 3

8 11 Lilydale Lake 4601 bedrock at surface WTA WTA Low low 0.4 - 1.9 (median = 1.5) 3

9 12 Dorset Recreation Reserve, Croyden 1465 bedrock at surface WTA WTA very low very low 0.3 - 0.9 (median = 0.3) 3

10 13 Gillmour Park, Upper Ferntree Gully 747 bedrock at surface WTA WTA Low very low 0.1 1

11 14 Pakenham Race Course 2590 14 clay, 1 m sand, 17 m clay, 5 m sand WTA WTA Very low very low 0.3 - 0.6 (median = 0.45) 2

15 WTA WTA Very low very low 0.1 - 1.5 (median = 0.5) 21 12

16 Lyndhurst Melbourne Water Depot 763

11 m clay, 2m gravel, 24m clay, 6m sand, 4m clay, bedrock not struck

LTA LTA Medium low 0.5 - 14.5 (median = 1.5) 5

13 17 Cranbourne Race Course 478 20 clay and sand, 7 m sand then bedrock WTA WTA Very low very low 0.1 - 18.0 (ave = 0.8) 29


19 Rossdale Golf Club 1803

8 m sand, 64 m sandy clay, 9 m peat and sand, then bedrock

LTA LTA Medium very low 0.5 - 1.0 (median = 0.75) 2


21 Patterson River Country Club 1038

16 m clay, 8 m sand, 41 m clay, 13 m basalt, 15 m coal/sand/clay, bedrock not struck (TD 93 m) LTA LTA Medium medium 10.0 - 10.1 (median = 10) 2

16 22 Albert Park 0 25m sandy clay, then bedrock WTA WTA Very low low 0.2 - 7.6 (median = 1.4) 6

17 23 Spring Park GC 725 41m clayey sand, 3m sand, then bedrock WTA WTA Very low very low 0.1 - 5.2 (median = 0.4) 20

18 24 Sandringham GC 397 59m clayey sand, silt and clay,then bedrock WTA WTA Very low very low 0.1 - 3.9 (median = 0.7) 31

19 25 Kooringal GC 0 N/A LTA LTA High medium 11.4 1

20 26 More Park 0 44m basalt, 17m clay and sand, 19 basalt, 4m corse sand, bedrock not struck

LTA LTA High high 12.6 1

21 27 Brighton GC 250 67 m of silty clay and clay, then bedrock WTA WTA Very low very low 0.7 - 7.6 (median = 0.8) 14



Comparison of yield estimates from pumping tests to Broad Scale Map

Site Location No. (as shown on maps in Appendix H.

Location Site assessment No

Geology Aquifer tested

Aquifer present on Broad Scale Map

ASR capacity on Broad Scale Map

ASR capacity based on pumping test

Est. max yield from pumping test (L/sec)

Pumping test duration (days)

Pumping rate (L/sec)

available drawdown (m)

Specific capacity (m3/d/m)

22 Eastern Treatment Plant

28 4 m sand, 48 m clay, 24 m basalt, 22m clay/peat/sand, then bedrock

LTA Yes Medium High 15 4 15 25 -

23 Tullamarine Liquid Waste Disposal Site

29 16m basalt, 1m sand then bedrock LTA No Very low (aquifer not present)

High 13 1 1.4 7.5 150

24 Kangan-Batman TAFE 30 53 m basalt, 6 m sand and gravel, then bedrock

UTA Yes Very low Medium 6 3.7 5 25 20

25 Mernda 31 37 m basalt, 3 m sand, then bedrock UTA No Very low (aquifer not present)

Low 4 1 2.4 18 20



Appendix H Broad Scale Maps with Reliability Assessment Sites Figure 16 Map of reliability assessment sites for the WTA



Figure 17 Map of reliability assessment sites for the UTA



Figure 18 Map of reliability assessment sites for the MTA



Figure 19 Map of reliability assessment sites for the LTA

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