.tMR. PVBUCA TiO~'iS COMPAClU (LENDING SECI'lON) ~

BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS

RECORD

RECORD 1987/7

MURRAY BASIN HYDROGEOLOGICAL PROJECT

PROGRESS REPORT 16

for half year ending 30 September 1986

compiled by

G. E . Wilford

The informetion conteined in this report has been obtained by the Bureau of Mineral Resources. Geology and Geophysics as part of the policy of the Australian Government to assist in the exploration and development of mineral resources. It may not be

I q a 7! j bliShed in any form or used in a company prospectus or statement without the permis.ion in writing of the Director.

RECORD 1987/7

MURRAY BASIN HYDROGEOLOGICAL PROJECT

PROGRESS REPORT 16

for half year ending 30 September 1986

compiled by

G. E. Wilford

"' u "~" ~ *R8700701*

TABLE OF CONTENTS

Page

PROGRESS REPORTS

SOUTH AUSTRALIAN DEPARTMENT OF MINES AND ENERGY 1

WATER RESOURCES COMMISSION OF NEW SOUTH WALES 3

GEOLOGICAL SURVEY OF NEW SOUTH WALES 5

RURAL WATER COMMISSION OF VICTORIA 8

DEPARTMENT OF INDUSTRY, TECHNOLOGY & RESOURCES 11

VICTORIA

BUREAU OF MINERAL RESOURCES 14

RECENTLY PUBLISHED AND UNPUBLISHED REPORTS ON THE

GEOLOGY AND HYDROGEOLOGY OF THE MURRAY BASIN

APPENDIX - General Statement - Murray Basin

Hydrogeological Project

FIGURE 1

FIGURE 2

FIGURE 3

FIGURE 4

Locality Map

Geological mapping areas, N.S.W.

Distribution and thickness of the

Oliogocene-Miocene Geera Clay, in the

Murray Basin, southeastern Australia.

Diagrammatic representation of Miocene

palaeofacies in the Murray Basin.

21

22

2

7

17

18

SOUTH AUSTRALIAN DEPARTMENT OF MINES & ENERGY

The detailed regional assessment is continuing with emphasis

on the northern region. A final investigation well to the

confined aquifer was drilled 40 km north of Waikerie.

The three layer finite element computer model has been used

to predict the effects of land clearing using recharge rates

obtained by the CSIRO Division of Soils (0.1 mm uncleared,S mm

cleared). After 500 years, groundwater inflows to the River

Murray increased by 2-3 times in some reaches.

The final of three 2-week aquifer tests at different sites

at the Woolpunda Interception Scheme was completed with

confirmation of previously derived aquifer parameters. A 6-month

aquifer test is about to start with the aim of evaluating

production hole completions and pump types, and methods of

eliminating troublesome iron carbonate precipitation.

1

/r-\

SOUTH-- ...... \ I---

A-

U-

S T R A '- OLARY·.··.N~.

BURRA

o I

(Sased an 19/A/II)

L I ~ __ ""~iLlYAMA .. ··<BL9CK

'\. . . <¢~~ .......•.... >

IOO~m I

·~-:C::S:;;'N..-t------t--:::7~~~-t-------J3S000'

FIGURE 1 Locality Map

Joint BMRjWRC 1986 Drillhole locations:

I. Nambucurra 7. Ar lington

2. Top Hut 8. Coronation Tank

3. Lake Garnpung 9. Mitford's Corner

4. lona 10. Woodlands

5. Bramah 1I. Mar ilIa

6. Hatfield 12. Neckarboo Ridge

2

WATER RESOURCES COMMISSION OF NEW SOUTH WALES

by

D. Woolley

1. GEOPHYSICS

Introduction

Geophysical mapping of the fine structure of the PLe-Tertiary

basement continued in the general area bounded by Euston,

Balranald and Hatfield. Basement Ridge (fault ?) structures with

up to 300m relief have been found.

Methods

Seismic refraction and detailed surface gravity profiling

gives best basement topography definition in the study area.

Resistivity gives information on the salinity of the

unconsolidated sediments. Preliminary trends show that salinity

is generally decreasing to the north, but in some areas patterns

appear to be perturbed by local recharge conditions. Ground

magnetics using both f1uxgate (vertical field), and proton

3

Statistics

Refraction:

Gravity:

Magnetics:

Resistivity:

2. GENERAL

Euston - Balranald Line

(Courtesy of BMR)

Euston - Balranald Line

Iona

Euston - Balranald Line

Iona

Bramah

(DC Schl umber ger )

Euston - Balranald Line

Mandleman

Loch Lomond

60 krn

71 krn

21 km

40 krn

24 km

35 km

21 Soundings

3

3

Monitoring in the piezometers constructed in the Joint

BMRjWRC Drilling Project has commenced. Water levels will be

measured twice yearly (summer and winter). An additional forty

one existing shallow piezometers constructed along the lower

Darling River in the early eighties have been incorporated into

this monitor ing program.

A report on the Groundwater Investigation at Prungle Lake in

4

the Willandra Lakes World Heritage Region was completed in

October, 1986. Shallow groundwater was found to flow toward the

Prungle Lake system which is a groundwater discharge area, viz

evapotranspiration. As the water table is shallow and the

surface strata are relatively permeable, any increase in

groundwater recharge, caused for instance by clearing of native

vegetation and farming, could result in a rise in the water

table.

Modelling of the groundwater flow system is being carried

out for Prungle Lake and will be reported on separately.

GEOLOGICAL SURVEY OF NEW SOUTH WALES

1. COAL EXPLORATION - OAKLANDS BASIN

Coal Cliff Collieries Pty Ltd (CRA) have continued drilling

their Oaklands South area (A207,A250).

A six monthly report for the period ending September 1986

has been received. It includes further lithological and

geophysical logs as well as coal quality data.

Coal reserves have been assessed and detailed mine planning

is underway.

The Coal Geology Branch of this Department has compiled a

5

report (which is now being reviewed) on the geology and coal

resources of the Oaklands Basin for inclusion in the proposed

Coal Bicentenary Volume to be published by the BMR.

2. PETROLEUM EXPLORATION

No petroleum exploration has taken place since the

completion of three wells by Claremont Petroleum PEL 212 in the

half year ended March 1986.

No further exploration field operations (other than the

rehabilitation of previous seismic lines) are expected in the

next 12 months. No licences have been granted or relinquished.

3. MINERAL EXPLORATION

CRA is currently exploring for heavy mineral sands in an

area mainly to the east of the Darling River. The area held

under exploration licences has been reduced but final reports on

the relinquished areas have not yet become available.

Exploration licences for gypsum are currently held by CSR

Limited in the Ana Branch area. Exploration reports are not yet

available.

6

'"'l H G) c::: ::u tI:I

N

G) (()

0 I-'

-...J 0 lQ ..... 0 AI I-'

3 AI '0 '0 ..... ::l

lQ

~ (() AI CJ)

Z Ul ::E!

An Index to 34'.,'

MURRAY BASIN 1:250 000

GEOLOGICAL MAPPING PROJECT 35' '[2I-t:j~ ,,·"' .. ::.1·( .' J 1/ / I 'j ~;~, I PROGRESS . DATE OF

REPORT Air photo interpretation I'

11m Landsat interpretation 2·

Field mapping , checking 3'

Tertiary Cross Sections 4'

Field repor t 5' Geophysics 6'

Related line , point data l'

. Biostratigraphy •• Coal/Lignite notes I'

Hydrocarbon potential 10'

Other Resources 11'

Final 1.250000 map 12'

Final report 13'

GealogiSi DATE OF GlllolUllisl REPORT

14·

IS·

16·

17·

II'

19'

20'

21,

22'

23'

24·

25·

26'

3535'

SCALE 20 .0

km

Base map adapted Itom C,M.A. 1:1500000 'late topographic: map

lq.... ','''$-!~ I ' !6'

'--------1. 3610.

16680

4. GEOLOGICAL MAPPING

The Geological Survey of New South Wales has commenced a

project to compile 1:250 000 scale geological mapping of the Ana

Branch, Pooncarie, Booligal, Balranald, Hay and Deniliquin sheet

areas.

The extent of the area to be mapped has been defined and is

shown in Figure 2. Familiarization studies have commenced, and

the geologists involved have made field trips to the region,

particularly the Ana Branch and Pooncarie areas, and Victorian

and South Australian parts of the basin. Contact has been made

with some of the other Departments active in the region, and the

Geological Survey anticipates increased involvement in land use

planning in the region.

RURAL WATER COMMISSION OF VICTORIA

BY

R. EVANS

The Rural Water Commission of Victoria is engaged in the

following hydrogeological studies in the Murray Basin:

1. Nyah to South Australian Border Hydrogeological Project

29 section line bores drilled, mostly between Red Cliffs

and S.A. Border, also near Marangatang and Robinvale.

(V

8

4 deeper bores penetrating top of Bookpurnong Beds, to

determine Parilla Sand aquifer geometry.

1 pumping test bore constructed, plus observation bores.

Riverbank sections mapped in detail at end of 10 section

lines between Red Cliffs and S.A. border: 2 sections

near Robinvale.

2. Girgarre Salinity Investigation

Extensive discussions on the feasibility and need for an

evaporation basin at Girgarre were carried out.

Monitoring of existing pump performance continued.

3. Barmah Forest

Effects of recent flooding on aquifer recharge is being

monitored.

Regional monitoring is continuing.

4. Shepparton Regional Drilling Program

Drilling proceeded on sections in the Shepparton Region. On

the Punt Road-Kialla section bores are being drilled to 50

metres depth and sealed piezometers are being installed

at various depths.

5. Broken River Diversion Weir Hydrogeological Investigation

Geophysical surveys and drilling were used to define the

geology in the vicinity of the proposed Broken River

9

l1

Diversion Weir. Groundwater flow modelling was used to

determine what effect the weir would have on water tables

beneath adjacent properties. A report is being prepared.

6. Shepparton Region Groundwater F10w Mode11ing

The Girgarre Model is being calibrated for the third year.

A multilayer finite element model of the Ardmona area is

being set up and solute transport will also be modelled in

this area. A model of groundwater flow in the Katunga area

of Murray Valley is also being established.

7. Farm Exp1aratary Dril1ing Scheme

Assistance is continuing to be provided to farmers to locate

shallow aquifers which could be pumped to supplement surface

water supplies and also to assist in lowering water tables.

This work has been greatly enhanced by the acquisition of an

EM34 surface electromagnetic induction meter which is

capable of detecting shallow, low salinity aquifers.

Investigations on 8 properties were completed.

8. Subsurface Database Management System

The Water Commission has begun the development of a

comprehensive computer based groundwater data base.

Currently data is stored in a variety of forms. The

proposed system will systemarise all storage procedures and,

most importantly, allow ready access to all data. Data on

the RWC 7,000 observation bores and 27,000 private bores

will be stored. The project is currently in the system

specification and database design phases.

10

1·"----

9. Mildura Weir Withdrawal Monitoring

An investigation was undertaken to study the effects of the

withdrawal of the Mildura Weir in June on groundwater levels

and salt accessions to the River Murray. Daily monitoring

of river flows and river salinities at 3 locations and

groundwater levels for up to 168 bores was carried out.

Analysis of the monitoring results has commenced.

10. Mallee Cliffs Groundwater Interception Investigation

The consultant report on the scheme feasibility has been

submitted to the RMC steering committee. Review of various

aspects of the project is continuing.

11. South Australian/Victorian Border Groundwater Sharing

Agreement

Several meetings of the Border Review Committee have been

carried out. This new legislation establishes a legal

framework for the equitable distribution of the groundwater

resources of a 40 km wide zone running along the S.A./Vic.

Border. It is proposed that the results of a number of

studies currently underway will be used to refine the volume

of water available for allocation.

DEPARTMENT OF INDUSTRY, TECHNOLOGY AND RESOURCES, VICTORIA

BY

C.R. Lawrence & R. Lakey

The expanded physical research and investigation program in

11

17

salinity in the Riverine Plain and Wimmera is now beginning to

produce some significant results.

Recent drilling in the eastern Wimmera Region, particularly

in the Richardson and Avon river catchments, has disclosed a

hydrogeological situation similar to that which exists in the

Riverine Plain. Shallow aquifers with high water tables are

underlain by a pressurised basal gravel aquifer which is

discharging into the shallow aquifer systems. Drainage lines

throughout the area reflect salinity stress in distressed and

dying deep rooted vegetation. The Marnoo area went saline

shortly after the 1973/75 wet period. Some 2000 ha, mainly in

the vicinity of Lake Buloak, are already affected and preliminary

estimates indicate that up to 10 000 ha could be seriously

affected in the event of a major recharge event akin to the

1973/75 wet. Increasing stream and water supply salinities have

been observed in the Richardson and Avon river catchments.

Recent work in the Shepparton area has shown that recycling

and reuse of shallow groundwater has produced a measurable

increase in the salinity of the shallow groundwater of about 50

mg/L/ann. To what extent this increase is due to the lateral

ingress of more saline groundwater, the upward leakage of more

saline groundwater, or increased leaching of salt stored in the

soil, is not yet clear.

By comparison, monitoring of the Phase A dewatering scheme

in the Shepparton Region comprising 80 pumping bores with 50%

reuse and 50% disposal, has shown that, in all but a few bores

12

(approx. 10), while seasonal fluctuations occur, there is no

overall rising trend in the salinity of the shallow groundwater.

In general the initial rise in salinity observed in most bores

when pumping commenced has reduced with time and stabilised at

about 1000 mg/L TDS.

Construction of additional shallow and deep groundwater

observation bores has significantly improved the groundwater

monitoring capability in both dryland and irrigation areas.

Preliminary observations of the impact on shallow aquifer water

tables of pumping from deep lead sand and gravel aquifers

suggests that, while a significant reduction in water tables

occurs in dryland areas overlying the deep lead, the effect on

water tables in the intensively irrigated areas appears to be

relatively minor.

Recent drilling has shown that the occurrence of high water

tables and salinity problems in the Shepparton area is often

associated with the occurrence of relatively shallow bedrock

overlain by Shepparton Formation material with little or no deep

lead material present. The presence of better developed lateral

and vertical drainage where the deeper aquifers underlie the

Shepparton Formation aquifer is an important controlling factor.

The loss of this deep drainage capacity as deep groundwater

pressures continue to rise and discharge to the overlying shallow

aquifers commences, will increase significantly the long-term

dewatering and disposal requirements.

Inspection of updated groundwater observation bore -17

13

hydrographs reinforces the observed general rise in watertables

and pressures throughout the Riverine Plain. However, it is

apparent that private pumping from the deep aquifers,

particularly in the Campaspe, Rochester, Murray Valley and

southern Loddon areas, can at least locally control the general

rise in deep lead pressures.

A program of deep drilling and seismic surveys is being

undertaken in the Mallee region to better understand the

relationship between regional groundwater flow, regional

geological structure and discharge of groundwater to the Murray

River and land. A detailed report will be given in the new

progress report on the findings of the work. Drilling of

observation bores continues along the South Australian/Victorian

border as a requirement of the Border (Groundwater) Agreement and

Act (1985).

BUREAU OF MINERAL RESOURCES

Documentation of Geological Data

by

C.M. Brown

MURRAY BASIN SUBSURFACE STRATIGRAPHIC DATABASE:

During the review period the Division of Continental Geology

has issued a subsurface stratigraphic database for the Murray

Basin. Published as BMR Report 262, it documents the interpreted

I~

14

downhole stratigraphy of 3000 boreholes drilled into the

Cainozoic succession of the Murray Basin. The use of the

database is clearly not restricted to groundwater applications,

and it has therefore been published for use by other workers in

the basin.

Though emphasis has been placed on documenting the

distribution of Cainozoic stratigraphic units, the database also

contains information about the underlying pre-Cainozoic units.

These include Precambrian basement and Adelaidean to Lower

Carboniferous metasedimentary, sedimentary, volcanic and

granitoid rocks, overlain by thin discontinuous remnants of

Permian, Triassic, and Cretaceous sedimentary rocks preserved in

poorly defined infrabasins. Brief summaries of both the regional

geology and individual stratigraphic units are included in

the Report.

A major objective of the borehole study has been to

establish a basin-wide stratigraphic framework by documenting the

regional distribution, geometry, and depositional environments of

the Tertiary stratigraphic units and major aquifers of the basin.

For this purpose, interpretations of borehole stratigraphy were

entered into a computer database, established to facilitate the

preparation of subsurface maps depicting concealed geology and

aquifer geometry in the Murray Basin. The database can be

accessed using a number of retrieval strategies, which allow

sorting and extraction of data specific to a particular map

sheet, stratigraphic unit, or regional aquifer. The major

datasets which were generated are tabulated in a series of

15

microform appendices to Report 262, and record downhole

stratigraphy in individual boreholes, as well as the distribution

and thickness of stratigraphic units and aquifers. The

microform appendices also contain 28 1:250 000 sheets showing

borehole localities.

Application of the Database - an example:

An example of automated contouring produced from the database (on

an Intergraph graphics terminal) shows isopachs of the Geera

Clay, an Oligo-Miocene unit consisting mainly of black clay (Fig.

3). This unit forms one of the major aquitards of the basin and

its distribution can be used to explain the occurrence of some

groundwater discharge features. It was deposited in marginal-

marine, interdistributary bay and tidal flat environments.

Palaeogeographic reconstructions of the Oligo-Miocene, based on

the borehole study, indicate that these environments were flanked

to the southwest by a narrow zone of restricted-marine and

lagoonal environments, bordering an extensive shallow-marine

platform over which calcarenites were deposited (Fig. 4). Peat­

forming swamps, and deltaic and fluvial environments occurred to

the north and east of the arcuate zone of deposition of the Geera

Clay. The Geera Clay therefore separates fluvial sands of the

Olney Formation (Renmark Aquifer) in the east and north from

calcarenite formations to the west and south (Murray Group

Aquifer). Groundwater flow patterns indicate that drainage

occurs towards the main depocentre of the basin in the central

western part of the basin. Consequently, the permeability

barrier created where the Renmark Aquifer is stratigraphically

truncated by the Geera Clay has resulted in present-day

16

groundwater flow disruption and upward leakage, which find

surface expression in a broad band of modern groundwater

discharge zones, as well as in the apparent ponding of surface

drainage in the form of lakes.

... sOtl71lERN ~ ...... ~.: ". , .

~

0"'7', ..

144

I ~"

NSW

FIGURE 3 Distribution and thickness of the Oligocene-Miocene

Geera Clay in the Murray Basin, southeastern Australia.

17

WEST EAST

FIGURE 4. Diagrammatic representation of Miocene palaeofacies in

the Murray Basin.

Report 262 can be purchased from the BMR Bookshop in

Canberra, and Australian Government Publishing Service (AGPS)

Bookshops in all capital cities. The price is $14.95 (plus

postage - 275g).

HYDROGEOLOGICAL PHASE

by

J.R. Kellett

JOINT BHR-WRC DRILLING PROGRAM:

Nested piezometers were installed at twelve sites as part of

the joint BMR-WRC drilling project in the western Murray Basin in

18

N.S.W. The bores are located in the western Riverine Plain,

Ivanhoe Block, Wentworth Trough and on the Lake Wintlow Gravity

High (Fig. 1).

Large volumes of highly saline groundwaters were discovered

at the MITFORDS CORNER site in the northern Wentworth Trough; the

potentials in the Pliocene Sand and Renmark Group Aquifers

indicate that the groundwater flow direction is from the Darling

River eastwards towards the northern Wentworth Trough. The

MANILLA hole in the central Wentworth Trough bottomed in massive

quartzite at 333m - the surprisingly shallow depth indicating

that the Wentworth Trough is a more complex structure than was

originally thought. At the time of writing the WOODLANDS bore,

on the Lake Wintlow gravity high, has reached 346m without

intersecting basement.

Four of the drill sites are located on the western limb of

the Ivanhoe Block. The NECKARBOO RIDGE bore was fully cored and

intersected an Oligocene-Miocene marine Winnambool Formation­

Geera Clay sequence, entirely enveloped by non-marine sediments

of the Renmark Group. An identical succession was encountered at

the TOP HUT site 50 km to the northeast. Further north, the

NUMBUCCURRA bores encountered continental Renmark Group sediments

only - thus indicating the limits of the Miocene marine

transgression. The northern-most drill site at CORONATION TANK

confirmed the presence of the basement ridge at the western

margin of the Ivanhoe Block, as inferred from earlier seismic

work.

19

The LAKE GARNPUNG bore was drilled in the centre of the

Willandra Trough and intersected large quantities of good quality

stock water (4500 ppm TDS) in the Eocene Renmark Group Aquifer.

The ARLINGTON bore, 40 km to the east, also intersected similar

good quality waters (2000 ppm TDS).

The Iona bore (western edge of the Balranald Trough) and the

HATFIELD site (centre of the Balranald Trough) both intersected

very fine-grained continental sediments throughout the full

Tertiary sequence, a surPLising result since it is known that

extensive Pliocene and Miocene channel sands occur within

equivalent sediments to the south around Box Creek.

The BRAMAH hole, located 35 km northwest of Balranald

encountered a surprisingly thin (40m) Miocene marine sequence.

Significant quantities of reasonable quality stock water (6000

ppm TDS) were intersected in the lower part of the Renmark Group

Aquifer.

Basement cores were taken at each site - Devonian sandstones

were cored beneath the Tertiary at TOP HUT and LAKE GARNPUNG:

Devonian ? volcanics were encountered at CORONATION TANK, and

?Cambro-Ordovician metasediments in NECKARBOO RIDGE, NAMBUCCURRA,

ARLINGTON, IONA, and BRAMAH.

Palynological stUdies are currently being undertaken on the

carbonaceous sections of the 8 uncored holes and at systematic

sampling intervals within the 4 fully cored holes. Preliminary

results indicate that MITFORDS CORNER has bottomed in Cretaceous

20

sediments; a Pliocene ligneous zone occurs in the BRAMAH hole;

all other analyses confirm the expected Eocene-Miocene sequence

in the Renmark Group.

86/87 Drilling Program:

Arrangements are well advanced for drilling in 1986/87. Four

sites have been targeted in the western Riverine Plain, one in

the southern part of the Wentworth trough, one on the Euston

seismic line, and one in the Blantyre Trough.

Campaspe Hydrochemistry:

Dr A. Arad (visiting scientist from the Geological Survey of

Israel) analysed hydrogeological data from the Campaspe Valley,

supplied by the DITR of Victoria. He has detected a diminishing

rate of rise in hydraulic heads in the Shepparton and Calivil

Aquifers throughout the valley - the turn-around commenced after

1980. Dr Arad postulates that this part of the basin has now

attained equilibirum with respect to modern land-use practices;

chemical and isotope studies indicate that irrigation in the

valley has negligible effect on groundwater salinities.

RECENTLY PUBLISHED AND UNPUBLISHED REPORTS ON THE GEOLOGY

AND HYDROGEOLOGY OF THE MURRAY BASIN

BROWN, C.M., & STEPHENSON, A.E., 1986 - Murray Basin,

southeastern Australia: subsurface stratigraphic database.

Bureau of Mineral Resources, Australia, Report, 262.

21

APPENDIX

MURRAY BASIN HYDROGEOLOGICAL PROJECT

Description and status

This project is a long-term study which is being undertaken

jointly by South Australian, Victorian and New South Wales

geological surveys and water authorities and by the Commonwealth

Bureau of Mineral Resources, Geology and Geophysics. It is

coordinated by a Steering Committee comprising members of those

organisations.

The Murray Basin is a geological structure with an areal

extent of some 300 000 km2 • In each of the three States, the

basin sediments contain very large groundwater reserves. Where

the groundwater has a low salinity it is increasingly being used

for irrigation and town water supply purposes. In much of the

basin, the water is suitable only for stock use and is

extensively used for this purpose. In other parts of the basin,

the groundwater is too saline for any use. There is a complex

interaction between groundwater and surface water which may be

beneficial, as in recharge areas in some parts of the basin, or

harmful as in areas of saline groundwater discharge to rivers.

In recent years, the states involved have stepped up the rate of

assessment of the groundwater regime in the basin.

The primary aim of the Project is to improve the

understanding of the groundwater regime of the basin by examining

it as a single entity, unencumbered by State boundaries. Since a

22

knowledge of the geology of an area is basic to the understanding

of groundwater occurrence, a geological study of the basin is an

essential part of the Project and, as a consequence, it will also

be possible to make an assessment of other mineral resources.

The project was planned initially to last five years and is

organised in five phases:

(1) Geological synthesis, using all available geological and

geophysical data.

(2) Hydrogeological assessment, on the basis of available data.

(3) Documentation of deficiences in geological and

hydrogeological information and formulation of proposals for

appropriate work programs.

(4) Additional work as approved which could include stratigraphic

drilling, aquifer testing, biostratigraphic analysis and

isotype hydrology studies.

(5) Development of numerical model(s), if found to be appropriate

in the light of the data then available.

The geological synthesis is nearing completion, and a draft

document reporting results, with accompanying 1:1 scale

geological maps, is expected to be finished by late 1986.

Phase 2 began at BMR in 1983. Hydrogeological data available

23

from the States are being entered into a BMR data base designed

for the project; BMR and State workers will prepare a report

assessing these data, and the results will be illustrated on

several maps including the following:

1:1 million scale maps showing water table,

potential contours and salinity variations for the

three or four most important hydrostratigraphic

units;

1:2 million scale maps showing (i) amount of water

abstracted-added per unit area (ii) recharge­

dischar ge areas, distr ibut ion of aquifer par ameter s

for a 7 layer hydrogeological model. (Both Victor ia

and South Australia have tested the feasibility of

making a preliminary model of the basin as a whole

based on a coarse (75 km) rectangular grid).

The hydrogeological assessment and phase 3, the documentation

of deficiencies in geological and hydrogeological information,

are scheduled for completion in 1986.

Additional work required in Phase 4 (e.g. stratigraphic

drilling, geophysical investigations) may be conducted by BMR or

by appropriate State authorities. The development of numerical

model (Phase 5), if found to be feasible, may be undertaken by

BMR or by State authorities. The Project will depend on the

close co-operation of staff from all organisations involved, and

some movement of staff between organisations for short periods

24

will be necessary. Throughout the study, individuals and

organisations will be encouraged to publish results of various

aspects of the work. Results of the overall Project will be

incorporated into joint publications.

25