Report on Groundwater Impact Assessment Rocky Gully Road ... · Bowen Hills, QLD 4006, Australia T....

Australasian Groundwater and Environmental Consultants Pty Ltd (AGE)

Report on

Groundwater Impact Assessment

Rocky Gully Road, Coominya

Prepared for

Zanows’ Concrete and Quarries Pty Ltd

Project No. G1729A May 2017www.ageconsultants.com.au ABN 64 080 238 642

AGE Head Office Level 2 / 15 Mallon Street, Bowen Hills, QLD 4006, Australia T. +61 7 3257 2055 F. +61 7 3257 2088 [email protected]

AGE Newcastle Office 4 Hudson Street, Hamilton, NSW 2303, Australia T. +61 2 4962 2091 F. +61 2 4962 2096 [email protected]

Document details and history

Document details

Project number G1729A

Document title Groundwater Impact Assessment, Rocky Gully Road, Coominya

Site address Rocky Gully Road, Coominya

File name G1729A.Report_v04.01.docx

Document status and review

Edition Comments Author Authorised by Date

v01.01 Internal draft report HM DWI 17/01/2017

v02.01 Draft report for client comment DFB AMD 21/02/2017

v02.02 Internal review HM DFB 28/04/2017

v03.01 Response to client comments HM DFB 28/04/2017

v03.02 Response to client comments HM DFB 2/05/2017

v04.01 Final HM DFB 25/05/2017

This document is and remains the property of AGE, and may only be used for the purpose for which it was commissioned and in accordance with the Terms of Engagement for the commission. Unauthorised use of this document in any form whatsoever is prohibited.

Australasian Groundwater and Environmental Consultants Pty Ltd

Australasian Groundwater and Environmental Consultants Pty Ltd Groundwater Impact Assessment, Rocky Gully Road, Coominya (G1729A) | i

Table of contents

Page No.

Introduction ......................................................................................................................................................................... 1 1

Project description ......................................................................................................................................... 1 1.1

Scope of work ...................................................................................................................................................................... 2 2

Site description ................................................................................................................................................................... 2 3

Terrain and drainage ..................................................................................................................................... 3 3.1

Climate ................................................................................................................................................................. 5 3.2

Hydrogeological regime .................................................................................................................................................. 6 4

Geological setting ............................................................................................................................................ 6 4.1

Groundwater occurrence and use ............................................................................................................ 9 4.2

Aquifer recharge ........................................................................................................................................... 13 4.3

Water levels .................................................................................................................................................... 13 4.4

Groundwater flow ........................................................................................................................................ 16 4.5

Groundwater quality................................................................................................................................... 18 4.6

Inflows and drawdown ................................................................................................................................................. 20 5

Inflows .............................................................................................................................................................. 20 5.1

Drawdown ....................................................................................................................................................... 23 5.2

Water balance ................................................................................................................................................ 27 5.3

Water licensing ................................................................................................................................................................ 30 6

Water Resource (Moreton) Plan 2007 ................................................................................................ 30 6.1

Water Resource (Great Artesian Basin) Plan 2006 ........................................................................ 31 6.2

Existing licences ............................................................................................................................................ 31 6.3

Conclusions ....................................................................................................................................................................... 32 7

References.......................................................................................................................................................................... 33 8

Table of contents (continued)

Page No.

Australasian Groundwater and Environmental Consultants Pty Ltd Groundwater Impact Assessment, Rocky Gully Road, Coominya (G1729A) | ii

List of figures

Figure 3.1 Project location ................................................................................................................................................ 4

Figure 3.2 Cumulative rainfall departure ................................................................................................................... 6

Figure 4.1 Surface geology ................................................................................................................................................ 8

Figure 4.2 Bores surrounding the site ....................................................................................................................... 12

Figure 4.3 Groundwater level hydrograph – RN 14320619 ............................................................................ 14

Figure 4.4 Groundwater level hydrograph – RN 14320618 ............................................................................ 14

Figure 4.5 Groundwater levels – other alluvium monitoring bores ............................................................. 15

Figure 4.6 Groundwater level hydrographs – sandstone bores ..................................................................... 15

Figure 4.7 Groundwater flow direction .................................................................................................................... 17

Figure 4.8 Piper diagram ................................................................................................................................................ 19

Figure 5.1 Analytical model - inflow into quarry and drawdown (Marinelli and Niccoli, 2000) ..... 21

Figure 5.2 Buffer distances surrounding the alluvial pits ................................................................................. 25

Figure 5.3 Monthly groundwater loss ....................................................................................................................... 28

Figure 5.4 Cumulative groundwater deficit ............................................................................................................ 29

List of tables

Table 3.1 Average monthly climate data ................................................................................................................... 5

Table 4.1 Summary of registered bores ..................................................................................................................... 9

Table 4.2 Summary of identified bores ................................................................................................................... 11

Table 4.3 Summary of groundwater quality data ............................................................................................... 18

Table 5.1 Analytical inputs ........................................................................................................................................... 22

Table 5.2 Analytical results .......................................................................................................................................... 23

Table 5.3 Maximum drawdown at existing users ............................................................................................... 26

Table 6.1 Water licences ............................................................................................................................................... 31

Australasian Groundwater and Environmental Consultants Pty Ltd Groundwater Impact Assessment, Rocky Gully Road, Coominya (G1729A) | 1

Report on

Groundwater Impact Assessment

Rocky Gully Road, Coominya

Introduction 1

Zanows’ Concrete and Quarries Pty Ltd (the proponent) propose to develop an extractive industry operation on a 323 ha rural site approximately 3.5 km southwest of Coominya in Queensland (Figure 3.1). The extraction facility will quarry both unconsolidated, alluvial sediments and weathered sandstone from three extraction areas to the north of Buaraba Creek. The extractive industry operation will have a maximum production capacity of 500,000 tonnes per annum (Mtpa), this equates to approximately 260,000 m3 of material removed per annum.

It is anticipated that the resource will be extracted from the alluvial flat located adjacent to Buaraba Creek. The two proposed alluvial extraction pits / ponds will be approximately 10 m to 15 m deep and are expected to intersect the groundwater table. Weathered sandstone will be quarried from a pit to the north of the alluvial sediments. Extraction of the weathered sandstone will not intersect the groundwater table.

This report describes the hydrogeological regime of the site and surrounding area and provides a groundwater impact assessment of the proposed extraction facility. The work has been undertaken by Australasian Groundwater and Environmental Consultants Pty Ltd (AGE) at the request of the proponent. This report has been prepared for inclusion in the project development application (DA).

Project description 1.1

The Project will comprise the following components:

a maximum production capacity of 500,000 Mtpa, this equates to approximately 260,000 m3 of material removed per annum;

approximately 20% of the extracted material will be returned to the pit as clay fines;

a proposed disturbance footprint of about 160 ha across three extraction areas, that is approximately 50% of the total land area of 323 ha;

two southern pits targeting the alluvial material excavated to the base of alluvium, approximately 15 metres below ground level (mbGL);

one northern pit targeting the unconsolidated weathered sandstone material above the water table;

two processing area within the disturbance footprint comprising the processing plant, stock piling area, weigh bridge, site offices, amenities, workshop, and ancillary facilities;

use of an existing water storage area for supply of processing water; and

two post closure (alluvial) voids in the final landform (i.e. dams).


Scope of work 2

The objective of the project is to assess the impacts of the proposed quarry on the groundwater regime which will result in the removal of sub-artesian groundwater. The site falls within two catchments listed under the Water Act 2000, and therefore, the scope of work addresses the requirements under the following legislation:

The Water Resource (Moreton) Plan 2007; and

The Water Resource (GAB) Plan 2007.

The scope of work addresses the following works:

compile a technical hydrogeological study to demonstrate compliance with the state and local government requirements and to ensure there are no adverse impacts downstream or on surrounding properties; and

explore the potential for transferring the existing water licence entitlements on the property from agricultural use into industrial use for extractive industry.

This report addresses the scope of work and includes the following:

review of the available geological and hydrogeological information including groundwater levels and flows measured in existing bores / drillholes, groundwater quality, structure of the major geological units and identification of the extent of aquifer units;

outcomes from meetings and discussions with the Department of Natural Resources and Mines (DNRM) representatives;

a site inspection to provide additional background data particularly surrounding existing groundwater users;

assessment of the factors that control the hydrogeological regime and the predicted volumetric take of groundwater by the proposed extraction facility; and

prediction of the net loss of groundwater from the aquifers owing to development of the extraction facility and assessment of impact of this extraction on the existing groundwater users.

Site description 3

The site is located at Rocky Gully Road, Coominya. The site is located on an alluvial flat (floodplain) on the northern side of Buaraba Creek, about 3.5 km southwest of Coominya (Figure 3.1). The proposed extraction facility is located on five properties (Lot 236 SP260138, Lot 246 CA31773, Lot 220 SP250792, Lot 225 CA31641 and Lot 226 CA31641) which are located within the Somerset Regional Council Local Government Area. The site covers an area of about 323 ha of which 160 ha is proposed for disturbance. The southern boundary is formed by Buaraba Creek and the northern and eastern boundaries by a mix of rural activities, including a poultry farm and a private airstrip.

An existing sand and gravel extraction facility operated by Hy-Tec Industries Pty Ltd is located on the western project boundary. The operating quarry is approved to take alluvial material.

The site extends across a low-lying alluvial floodplain (Figure 3.1). Most of the site has been cleared of native vegetation; the site has been and continues to be used for turf farming, the cultivation of crops, and for livestock grazing. The exception is native vegetation in the bed and on the banks of Buaraba Creek and two minor patches of native vegetation in the northwest of Lot 236 SP260138.


Terrain and drainage 3.1

The site is located within the Buaraba Creek sub-catchment which is part of the Lockyer Creek catchment. Lockyer Creek flows into the Brisbane River approximately 2.5 km downstream of Wivenhoe Dam.

Figure 3.1 shows the terrain of the site and surrounds. Most of the site is located on the alluvial floodplain of Buaraba Creek. To the north of the site, the terrain gradually rises as the alluvial sediments thin, and consolidated sedimentary rocks outcrop at the surface (Section 4.1).

Drainage features at the site are ephemeral and flow during and shortly after heavy rainfall events. Buaraba Creek is ephemeral and flow is influenced by the regulated retention and release of water from Atkinson Dam.

Atkinson Dam is located to the south of the site. Atkinson Dam was constructed in 1970 over an existing lagoon and collects water from a diversion from a weir constructed on Buaraba Creek. The dam also receives inflow via overflow from Seven Mile Lagoon. The dam is used to supply irrigation water via surface water releases back into Lockyer Creek, Buaraba Creek and associated channels and weirs. Buaraba Creek runs to the immediate south of the site. A minor drainage feature runs through the site from the north-west to the south-east.

The site is relatively flat, varying in elevation between approximately 50 metres above Australian Height Datum (mAHD) and 80 mAHD. The areas of higher topography occur away from Buaraba Creek.


Climate 3.2

The climate of the region is sub-tropical characterised by hot, wet summers and dry cool winters. Long-term climate data collected by the Bureau of Meteorology (BoM) is available from two nearby weather stations. Atkinson Dam (Station No. 40329) is located approximately 1 km south of the site and has a continuous climate record from 1997 to present. The Lowood Don weather station (Station No. 40120) is located approximately 12 km southeast of the site and has a continuous climate record for the period 1887 to present. Figure 3.1 shows the location of these weather stations.

The BoM data has been compared to an interpolated site-specific dataset obtained from the Scientific Information for Land Owners (SILO) service and provided by the Department of Science, Information Technology, Innovation and the Arts (DSITIA). The data is a ‘patched point dataset’, meaning that missing or suspect values are ‘patched’ with interpolated data. Table 3.1 details the average monthly rainfall from the SILO data, as well as from the BoM stations.

Table 3.1 Average monthly climate data

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual average

Rainfall (mm)

Site SILO data* 119.4 112.4 90.3 57.6 47.9 47.1 41.6 28.2 39.7 64.7 78.1 106.5 834.4

Lowood Don 116.3 102.4 90.1 55.7 48.6 49.3 38.3 29.7 39.3 64.7 77.1 100.8 816.5

Atkinson Dam 97.4 102.5 70.1 41.7 39.9 40.9 22.8 29.5 41.2 59.3 88.4 105 761.3

Evaporation (mm)

Site SILO data* 191.6 152.8 155 118.6 84.4 73.2 80.6 103.8 138.2 174 188.4 205.6 1,666.2

Note: * monthly average based on SILO patched point data from 1889 to 2016.

Recent rainfall years have been put into historical context using the Cumulative Rainfall Departure (CRD) method. This method is a summation of the monthly departure of rainfall from the long-term average monthly rainfall. A rising trend in the CRD plot indicates periods of above average rainfall, whilst a falling slope indicates periods when rainfall is below average. Figure 3.2 presents the CRD graph for the region using BoM daily rainfall data.

The CRD graph indicates that the region has experienced distinct cycles of above average and below average rainfall. The CRD graph indicates that since 1980 the site experienced below average rainfall between 1980 and 1995, 1999 to 2007, and 2012 to present. Conversely the site experienced above average rainfall between 1995 and 1999, and 2007 to 2012.


Figure 3.2 Cumulative rainfall departure

Hydrogeological regime 4

Geological setting 4.1

The site is located within the Late Triassic to Late Jurassic Clarence-Moreton Basin which covers an area of approximately 26,000 km2 of southeast Queensland and northeast New South Wales (Geoscience Australia, 2017). The Clarence-Moreton Basin stratigraphically overlies the Ipswich Basin and comprises Triassic to Jurassic aged sandstones, siltstones, and mudstones deposited in a predominantly fluvio-lacustrine depositional environment.

The Jurassic strata are unconformably overlain by Quaternary age sediments. The Quaternary sediments are associated with the floodplain of the present day Lockyer Creek and Buaraba Creek.

Available geological mapping indicates that the oldest rocks in the area are the Woogaroo Sub-group. The Early Jurassic-Late Triassic Woogaroo Sub-group (previously known as the Helidon Sandstone) forms the basement rock at the site (Figure 4.1). The Woogaroo Sub-group outcrops at the northern boundary of the site and thickens to the south. The unit comprises thin to thick bedded, fine to medium-grained, quartz-lithic and quartz sandstone, quartz-rich granule conglomerate, silty sandstone, siltstone, claystone; carbonaceous siltstone and claystone; minor laminites and coal.

The Woogaroo Sub-group is overlain by the Jurassic age Gatton Sandstone which is the lower formation of the Marburg Sandstone (Figure 4.1). The Gatton Sandstone comprises thin to thick-bedded, coarse to medium-grained, feldspathic to lithic feldspathic sandstone with clay matrix; subordinate intervals of granule, pebble and minor cobble polymictic conglomerate, with abundant ferruginised fossil wood logs and fragments.

-4000

-3000

-2000

-1000

0

1000

2000

3000

0

100

200

300

400

500

600

700

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020

Cu

mu

lati

ve

Ra

infa

ll D

ep

art

ure

(C

RD

)

Mo

nth

ly R

ain

fall

(m

m)

YearMonthly Rainfall - Lowood Don (ID:40120) CRD - Lowood Don (ID:40120)

CRD - Atkinson's Dam (ID:40329)


Buaraba Creek has eroded these Triassic and Jurassic aged rocks and the valley has been infilled with Tertiary and recent (Quaternary) sediments forming the alluvial plain. Sandstones of the Woogaroo Sub-group and Gatton Sandstone outcrop at the surface on the northern and southern sides of Buaraba Creek.

The Tertiary and Quaternary sediments consist of:

minor colluvial material mapped as Late Tertiary to Quaternary in age (clay, silt, sand, gravel and soil; colluvial and residual deposits);

alluvial sediments of Pleistocene age (clay, silt, sand, gravel; floodplain alluvium on high terraces); and

Holocene sediments to the east and west of site comprising sand, silt, clay and gravel. Within the banks of Buaraba Creek is the lowest river terrace of gravel, sand, silt, clay.

The alluvial plain at the site is about 1,500 m wide narrowing to 200 m upstream of the site. Downstream of the site the alluvial sediments can be up to 2,500 m wide. The alluvium is up to 20 m thick. The alluvial deposits consist of multiple layers of sand and gravel interspersed with thin interbeds of clay, silt and clayey or silty sand and gravel. The overburden material varies between about 2 m and 8 m thick and consists of soil, clay, silt and thin sand lenses.

A review of the lithological logs of resource test holes at the site indicates that the sand and gravel varies from very clean material up to 10 m thick, to silty and clayey sand and gravels. Registered bore RN 14320619 is a DNRM monitoring bore located within the site and in between the two proposed alluvial extraction pits. The Quaternary alluvium intersected at the bore is 11.4 m thick and comprises surficial loam, brown clay and silty clay to a depth of 5.7 mbGL. From 5.7 mbGL to 8.4 mbGL comprises sandy clay with coarse sand and gravel and claybound gravel from 8.4 mbGL to 11.4 mbGL.


Groundwater occurrence and use 4.2

Within the region, the Woogaroo Sub-group and the Quaternary sediments comprise the main aquifers utilised for water supply. The Gatton Sandstone is typically finer grained and bores drilled into this unit generally do not intersect usable quantities of groundwater. There are a number of groundwater bores within the region that are constructed to extract from the Woogaroo Sub-group or Buaraba Creek alluvium (Figure 4.2). It is from these bores that information on the hydrogeology is assessed.

The Woogaroo Sub-group typically yields stock and domestic supplies and occasionally will yield sufficient quantities of groundwater for irrigation purposes. The Quaternary sediments however can yield sufficient groundwater for irrigation purposes except on the margins of the Quaternary alluvium where the sediments are thin or unsaturated.

Given that the northern extraction pit targeting the unconsolidated weathered sandstone material (Woogaroo Sub-group) will remain above the water table, impacts associated with this aquifer are highly unlikely and the focus of the assessment relates to the Quaternary sediments. Groundwater occurs in all Quaternary sediments below the prime water table, however only the sand / gravel and to a lesser extent, the clayey and silty sand and gravel layers, are considered aquifers. The sand layers, although interspersed with clay layers, are considered to form a hydraulically interconnected, unconfined system which functions as a single unit. The clays, silts and sandy clays are considered relatively impermeable compared to the sand and gravel, and although saturated, do not transmit groundwater readily.

Information on registered bores within 5 km of site was provided to AGE by the DNRM in November 2016. The data included 31 bores with nine of these bores being government monitoring bores. Of the 22 remaining bores, only one was flagged as abandoned and destroyed, leaving 21 existing registered bores. These existing registered bores are summarised in Table 4.1 shown in Figure 4.2. Two of these bores are described as either stock and / or domestic bores (RN 66700 and RN 129463).

Table 4.1 Summary of registered bores

Registration No.

Lot No. Plan No. Easting Northing Drilled date Original Bore No.

59186 222 CA31641 448106 6966997 01/01/1959 FOX - IR

59187 218 SP100355 444408 6969224 01/01/1959 NEUMANN - IR

66700 26 RP135412 445043 6969940 18/07/1982 POCOCK O F & L F -DO

75118 71 CSH1328 449727 6966467 LINDE - IR

75162 2 RP912568 447450 6966471 01/01/1986 STEVENS - IR

75163 2 RP912568 447452 6965948 01/01/1986 STEVENS - IR

75742 341 CSH1945 445389 6967817 ATKINSON TWS BORE

129090 218 SP100355 444479 6969206 23/03/2005 DJ & M NEUMANN

129136 2 RP18324 448025 6966240 16/05/2005 DAVID KELLER

129371 447704 6966883 13/03/2003

129372 231 CA31641 447484 6967161 15/04/2002


Registration No.

Lot No. Plan No. Easting Northing Drilled date Original Bore No.

129452 341 CSH1945 445410 6967803 22/05/2006

129462 1 SP192457 443513 6968607 19/06/2006 IRRIGATION BORE

129463 1 SP192457 443508 6968601 24/06/2006 STOCK AND DOMESTIC BORE

129464 1 RP173246 443566 6968155 30/05/2006

143138 1 RP67864 449564 6966628 13/08/2007

143139 1 RP67864 449551 6966579 15/08/2007

143754 2 RP61381 443623 6968571 23/11/2009 NEUMANN

143755 221 CA31639 444721 6968828 11/11/2009 SMITH

154393 1 SP192457 443511 6969038 25/10/1993

154394 1 SP192457 442243 6967900 12/07/1994

Note: Coordinates are in GDA94, Zone 56.

Of the bores shown in Figure 4.2 and Table 4.1, RN 129090 is presumed to be a replacement bore for RN 59187 and RN 129452 is presumed to be a replacement bore for RN 75742. These assumptions are based on the proximity of these holes and the dates of drilling and construction.

The bulk of these registered bores are located on the southern side of Buaraba Creek with the exception of RN 129372, RN129371, RN 59186, RN 143138, RN 143139 and RN 75118 which are located on the northern side of Buaraba Creek to the east of the site. These bores are located approximately 535 m, 865 m, 1,180 m, 2,675 m, 2,680 m and 2,875 m from the site property boundary respectively.

In addition to this data, a bore census was carried out on the property on the 17 November 2016 with the intent of locating unregistered irrigation bores on neighbouring properties to the site. Table 4.2 provides a summary of the 17 bores located during the census. It is important to note that four of the 17 bores are either destroyed or abandoned. Of the remaining 13 bores, three are assessed to be completed within the Woogaroo Sub-group and one is assessed as completed within the Gatton Sandstone. This leaves nine existing bores that are assessed to be completed within the Buaraba Creek alluvium. These bores are shown in Figure 4.2. There are no known groundwater bores on the neighbouring Hy-Tec Industries property to the west of the site.


Table 4.2 Summary of identified bores

RN / Name Easting Northing Status Formation

106925 446129 6967709 existing Buaraba Creek alluvium

129863 447032 6968392 abandoned replaced

by 154972 Buaraba Creek alluvium

129866 - Lemon Tree Bore

445674 6967798 existing Buaraba Creek alluvium

154970 447163 6969146 destroyed unknown

143290 447183 6968519 existing Woogaroo Sub-group

106701 - G Banff 447186 6968906 existing Gatton Sandstone /

Woogaroo Sub-group


129865 - Well 446735 6967663 destroyed Buaraba Creek alluvium



106925 - Banff Bros 446129 6967709 existing Buaraba Creek alluvium

Old Well 445873 6967826 existing Buaraba Creek alluvium

Pivot Bore 445955 6968318 existing Buaraba Creek alluvium


Orchard Bore (replacement)

445886 6967962 existing Buaraba Creek alluvium

Orchard Bore (abandoned)

445886 6967960 abandoned Buaraba Creek alluvium

Burns Bore 447056 6967259 existing unknown, presumed Buaraba

Creek alluvium

Note: Coordinates are in GDA94, Zone 56.

Only one of these existing Buaraba Creek alluvium bores located during the bore census (Burns Bore) is on a property that is outside the proposed site. The bore is located approximately 150 m from the site boundary and is used only for stock and domestic purposes. Furthermore, the Burns property does not use groundwater for any other purpose other than domestic supply. Their irrigation water supply is entirely sourced from two water allocations from Atkinson Dam and from their privately owned dam which is replenished from rainfall and runoff. The impact of extraction on the groundwater levels at Burns Bore is discussed further in Section 5.2.


Aquifer recharge 4.3

Recharge to the sand and gravel aquifer system would occur by direct infiltration of rainfall through the overlying soils, clay and silt, by runoff and from discharge through the sandy base of Buaraba Creek, during periods of stream flow. It is considered that due to the thickness and clayey nature of the overburden material, direct infiltration of rainfall is only a minor contributor of aquifer recharge, and that infiltration through the bed of Buaraba Creek during stream flow following high rainfall or releases from Atkinson Dam, is the main recharge mechanism to the alluvial groundwater system.

Ellis (1999) estimated that recharge through the unsaturated surface profile of clays and silt within the alluvial sediments of the Lockyer Valley was likely in the order of 12 mm/yr. A recharge rate of 12 mm/yr is equivalent to 1% of annual rainfall in this region.

It is possible that the surficial soils at the outer margins of the alluvium would be sandier reflecting the presence and proximity of the underlying Woogaroo Sub-group. If this is the case, the recharge rates on the margins of the alluvium (where it would also receive greater runoff from elevated terrain) would be higher than those areas of alluvium that are influenced more so by overbank flood deposits, which tend to be finer grained. However, this suggestion of higher recharge along the alluvial margins is purely conceptual and there is no data to support this in this region.

The Woogaroo Sub-group would primarily receive recharge by direct infiltration of rainfall through the overlying soils and weathered profile. Due to the clayey nature of the weathered overburden material, direct infiltration of rainfall would be relatively minor when compared with the recharge to the alluvial sediments.

Water levels 4.4

An excellent groundwater level record is available from government monitoring bore RN 14320619 which is completed within the Buaraba Creek alluvium (Figure 4.3). Groundwater measurements at RN 14320619 date back to 1990 and reflect nearly 30 years of data. The hydrograph shows that the groundwater in the alluvium fluctuates by 7 m over the monitoring period. Water level rises are apparent from major rainfall / flood events and the hydrograph correlates well with the CRD. The most apparent recharge event occurred during the January 2011 floods where a 4 m rise was observed.

Government monitoring bore RN 14320618 is located some 400 m to the south of RN 14320619. The hydrograph for RN 14320618 (Figure 4.4) shows a very similar water level response. The alluvium at this bore is 11.5 m thick.

Figure 4.5 presents the groundwater levels in the nearby Quaternary alluvium bores. The data shows that the groundwater levels in the alluvium all respond well to short duration rainfall and streamflow events and correlate well with the CRD trend.

Figure 4.6 presents the hydrograph for RN 14320891 (Woogaroo Sub-group), RN 14320623 and RN 14320933 (Gatton Sandstone). The hydrograph shows a limited record for RN 14320891 (2010 to 2016), however, it does follow the CRD trend during that period. Bores RN 14320623 and RN 14320933 also correlate with the CRD trend, however, the response is subdued when compared to the alluvial monitoring bores.


Figure 4.3 Groundwater level hydrograph – RN 14320619

Figure 4.4 Groundwater level hydrograph – RN 14320618


Figure 4.5 Groundwater levels – other alluvium monitoring bores

Figure 4.6 Groundwater level hydrographs – sandstone bores


Groundwater flow 4.5

Figure 4.7 presents groundwater level contours for the Quaternary alluvium. Regional groundwater flow in the Quaternary alluvium reflects the terrain and follows the present day Buaraba Creek, towards the southeast. Localised changes in the groundwater flow direction are expected to occur nearby active pumping bores. Atkinson Dam is also expected to have an influence over the groundwater levels in the alluvium to the south of Buaraba Creek. During discharge events from Atkinson Dam, the hydraulic gradients in the alluvium surrounding Buaraba Creek would increase due to the presence of surface water in the creek. However, upon cessation of discharge, hydraulic gradients would gradually return to background as water moves along Buaraba Creek or recharges the alluvium.

Groundwater level monitoring data indicate the predominant direction of groundwater flow is downstream in the alluvial sediments of the floodplain; however, following flood events when the alluvium is recharged to above the level of the bed of the creek, a component of flow from the floodplain and topographically higher basement rocks toward the creek would be expected. Within the proposed sand extraction area, lateral flow into the creek is considered to be a minor component of groundwater flow, compared to that which flows downstream.

An approximation of groundwater flow that occurs in the aquifer sand and gravel across the width of the alluvial valley can be assessed using the form of the Darcy Equation, viz:

𝑄 = 𝐾 × 𝑖 × 𝐴

where: K = hydraulic conductivity

= 5 m/day for clayey and silty sand and gravel

i = water table gradient - assume average of 0.0025

A = cross sectional area of aquifer

= 1,500 m x 8 m for the saturated alluvium

Q = (5 x 0.0025 x 1,500 x 8) m3/day

= 150 m3/day or 1.7 L/s or 54.8 ML/year


Groundwater quality 4.6

Table 4.3 presents groundwater quality data from ten nearby DNRM groundwater monitoring bores (Figure 4.2). The samples were collected between 1990 and 2014.

Table 4.3 Summary of groundwater quality data

Screen lithology Unit Buaraba Creek

Alluvium Gatton

Sandstone Woogaroo Sub-group

Lockyer Creek sub-regional catchment

indicators

No. of bores - 7 2 1 -

No. of samples - 24 3 1 -

EC µS/cm 1,350 6,500 1,210 1,200

pH pH unit 7.7 8.2 7.6 6.5 - 8.2

TDS mg/L 785 3,868 660 -

Alkalinity mg/L 151 605 329 -

Hardness mg/L 349 767 237

Ca mg/L 66 60 58 -

Mg mg/L 48 150 22 -

Na mg/L 173 1,250 157 -

K mg/L 1.5 3.7 5.8 -

Cl mg/L 310 1,950 170 -

SO4 mg/L 15 39 14 -

HCO3 mg/L 183 720 399 -

CO3 mg/L 4 28 1 -

NO3 mg/L 18 3 <0.5 -

F mg/L 0.2 0.2 0.1 -

Si mg/L 50 22 33 -

Mn mg/L 0.02 0.03 <0.01 -

Fe mg/L 0.02 0.03 <0.01 -

Note: median values shown


Salinity is a key constraint to water management and groundwater use, and can be described by total dissolved solids (TDS) concentrations. TDS concentrations are commonly classified on a scale ranging from fresh to extremely saline. FAO (2013) provide a useful set of categories for assessing salinity based on TDS concentrations as follows:

fresh water <500 mg/L

brackish (slightly saline) 500 to 1,500 mg/L

moderately saline 1,500 to 7,000 mg/L

saline 7,000 to 15,000 mg/L

highly saline 15,000 to 35,000 mg/L

brine >35,000 mg/L

The data (Table 4.3) indicates that the groundwater is generally alkaline with a pH between 7.6 to 8.2. Groundwater in the Buaraba Creek alluvium and the Woogaroo Sub-group is brackish and moderately saline in the Gatton Sandstone.

The samples can also be compared to the southeast Queensland Lockyer Creek upper catchment sub-regional guideline for electrical conductivity (EC) and pH (Department of Environment and Heritage Protection, 2009). The data shows the median groundwater values for EC from the alluvium and the Woogaroo Sub-group are slightly above the regional guideline for the Lockyer Creek sub-catchment. Groundwater samples from the Gatton Sandstone are elevated likely reflecting a longer residence times for groundwater in this unit.

The proportions of the major anions and cations were analysed to determine the hydrochemical facies of each unit. The anion-cation balance is shown on the Piper diagram in Figure 4.8. The data show groundwater within the Woogaroo Sub-group is Na-HCO3 type, whereas the samples from the Gatton Sandstone are Na-Cl type. This distinction likely reflects the relative residence time of the samples. Generally older groundwater will be Na-Cl dominant whereas younger waters closer to the recharge source have a higher relative concentration of HCO3 due to carbonate dissolution on the soil zone.

Samples from the alluvium show a trend from no dominant cation to Na, and HCO3 to Cl type, this may reflect evaporation in the unsaturated zone or mixing of more saline water from the Gatton Sandstone.

Figure 4.8 Piper diagram


Inflows and drawdown 5

A monthly water balance of the excavated void is represented by the following equation and has been developed for the site.

Net loss / gain = Inputs - Outputs

The inputs to the water balance are rainfall, runoff and groundwater inflow, whereas the outputs of the system are represented by pond evaporation (during extraction and from the final voids post extraction), moisture content of the sand removed and the water used for plant operations.

The water balance does not assess the two pits separately; instead the total area of the combined southern pits is represented as a single surface. The pit lakes are represented as a percentage of the total pit area which grows proportional to the annual extraction volume until the final pit lake size is of 15% of the total pit area is reached. This is considered a conservative approach as it does not account for the batter slope angle and unsaturated pit walls.

The largest uncertainty within the water balance is the volume of groundwater inflow into the pits / ponds. The water balance conservatively assumes that the excavated void will always intersect the groundwater table and that the groundwater level at the site remains constant. The water balance provides sufficient groundwater inflow to account for the maximum evaporative losses from two alluvial extraction pits.

However, this is certainly not the case as during extraction, only one southern pit will be extracted at a time. Furthermore, as the quarry operations will be dry for a period of time during development and operations the evaporative losses will be less than calculated in the water balance. In addition to this, the groundwater levels at the site have been observed to fluctuate by 7 m over the 30 year monitoring period (Section 4.4). During dry climatic periods the excavated pits will generally be dry. In terms of the volume of groundwater extracted from the aquifer, the water balance is therefore considered to be a worst case scenario and conservative in nature.

Inflows 5.1

An assessment of likely groundwater seepage rates to the pits and the radius of influence from dewatering was undertaken using equations developed by Marinelli and Niccoli (2000). The analytical method requires a simplification of the hydrogeological environment and is used to provide a ‘broad’ range of potential drawdown and inflow. The equations separately calculate groundwater inflow from the pit walls (Zone 1) and from the base of the pit (Zone 2), based on the conceptual model presented in Figure 5.1. Conceptually Zone 1 represents groundwater inflow from the alluvium and Zone 2 represents upward seepage from the underlying Gatton Sandstone.


Figure 5.1 Analytical model - inflow into quarry and drawdown

(Marinelli and Niccoli, 2000)

Groundwater inflows were calculated for Zone 1 and Zone 2 using the following equations:

Zone 1: daymrrWQ po /)( 322

1

Zone 2: )(42

22 dh

m

KrQ o

hp

2

22

v

h

K

Km

where: Kh1 hydraulic conductivity value for the aquifer

ho saturated thickness of aquifer

W rainfall recharge rate

hp the height of the aquifer seepage face in the open excavation

rp equivalent radius of the extraction pits as a cylinder

Kv2 vertical hydraulic conductivity values for the aquifer

d depth of water level in pit

The extent of drawdown due to the net groundwater loss then allows for determination of the radius of influence of the loss on the water table by iteration from the following equation.

2

(ln

22

2

1

20

po

p

oo

hp

rr

r

rr

K

Whh

Q1 hp

W Centre of Pit

Q2

ho

Kh1

Kh2, Kv2

ZONE 1

ZONE 2

d No-Flow Boundary

0 rp r0

Q2


Zone 1 represents the Quaternary alluvium for the project and the analytical solution considers steady-state, unconfined, horizontal, radial flow and assumes that:

the excavation walls are approximated as a cylinder;

groundwater flow is horizontal; the Dupuit-Forchheimer approximation is used to account for changes in saturated thickness due to depression of the water table;

the static (pre-quarrying) water table is approximately horizontal;

uniform distributed recharge occurs across the site as a result of surface infiltration from rainfall; all recharge within the radius of influence (cone of depression) of the excavation is assumed to be captured by the excavation; and

groundwater flow toward the excavation is axially symmetric.

Estimation of groundwater inflow to the pit and extent of drawdown was undertaken for the likely range of effective hydraulic conductivity of the alluvial material and the saturated thickness of the alluvium. This range in hydraulic conductivity (1 m/day to 10 m/day) and saturated thickness (6 m to 12 m) was discussed with DNRM (Ashley Bleakley pers. comm. - 7 February 2017). Table 5.1 presents the inputs used in the Marinelli and Niccoli analysis.

Table 5.1 Analytical inputs

Input Description Value Comment

h0 pre-extraction saturated thickness of

Quaternary alluvium 6 m / 12 m

average water level in the Quaternary alluvium is approximately 3 mbGL

hp saturated thickness at the pit wall 1 m -

W distributed recharge flux 1.1 x 10-4 m3/d/m2 5 % of rainfall (whilst 1% of diffuse rainfall was discussed in Section 4.3, a higher value

of 5% allows for streambed infiltration)

kh1 horizontal hydraulic conductivity of

the Quaternary alluvium

1 m/day

5 m/day

10 m/day

horizontal hydraulic conductivity of the alluvium (Ashley Bleakley pers. comm. - 7

February 2017)

Kh2 horizontal hydraulic conductivity of

the Gatton Sandstone 0.03 m/day

approximate K for the Marburg Sandstone (New Hope Coal, 2014)

Kv2 vertical hydraulic conductivity of the

Gatton Sandstone 0.0003 m/day two orders of magnitude lower than Kh2

rp effective radius of the pit West pit: 200 m

East pit: 150 m based on practical working area of each pit

d height of water in the active pit 0 m no water in the base of the pit during

extraction

Table 5.2 summarises the calculated groundwater inflow and radius of influence based on the input data in Table 5.1.


Table 5.2 Analytical results

Pit Parameter K =

1 m/day

h0 = 12 m

K = 5 m/day

h0 = 12 m

K = 10 m/day

h0 = 12 m

K = 1 m/day

h0 = 6 m

K = 5 m/day

h0 = 6 m

K = 10 m/day

h0 = 6 m

West Pit

Alluvial inflow (L/s)

4.3 14.6 25.4 1.6 5.0 8.4

Sandstone inflow(L/s)

0.3 0.3 0.3 0.2 0.2 0.2

Radius of influence (m)

846 1,705 2,310 455 925 1,250

East Pit

Alluvial inflow (L/s)

3.7 12.9 22.7 1.3 4.3 7.4

Sandstone inflow(L/s)

0.3 0.3 0.3 0.1 0.1 0.1

Radius of influence (m)

815 1,640 2,220 440 890 1,205

The groundwater inflow from the Quaternary alluvium is calculated at a maximum rate of 25 L/s and 23 L/s from the western and eastern pit respectively. This inflow rate is calculated using the higher hydraulic conductivity value (10 m/day) and assuming a full saturated thickness of alluvium (12 m). Conversely, the minimum groundwater inflow calculated is 1.6 L/s and 1.3 L/s with a hydraulic conductivity value of 1 m/day and a saturated alluvial thickness of 6 m. Calculated inflow from the underlying Gatton Sandstone is between 0.1 L/s and 0.3 L/s per pit.

It is important to note that the analytical equation assumes that there is no water in the base of either pit during quarrying and that the inflow rates above require full dewatering of the alluvial profile to occur. In practice, this full dewatering of the alluvial profile will not occur and the calculations are considered conservative in this regard.

Drawdown 5.2

The radius of influence of each pit is predicted to be between 440 m and 2,310 m (Table 5.2) from the pit wall. The radius of influence will be dependent upon the hydraulic parameters of the groundwater system (hydraulic conductivity and storage parameters) of which only hydraulic conductivity is considered in this equation as it is a steady state approximation only.

The presence of Buaraba Creek as a recharge source will limit the radius of influence of each pit. It is highly likely that drawdown from the quarrying operation will not extend south of Buaraba Creek. This is due to the additional (and sometimes significant) recharge that would occur through the bed of Buaraba Creek during surface water flow events and controlled releases from Atkinson Dam.

It is important to note that as the quarry operations develop and migrate around the site, the ponds will be progressively backfilled with fine material (silts and clays) that is rejected during the washing process. The placement of this fine grained material will serve to reduce the bulk hydraulic conductivity of the alluvium and hence will reduce the potential inflows to the pits and will limit the radius of influence. The effect of the process cannot be modelled using the analytical equations provided in this report.


In addition to this, the analytical model assumes the geometry of the pit is a cylinder, some 6 m to 12 m in height (depending upon the scenario), which represents the saturated thickness of the Quaternary alluvium at the site. In reality, the alluvium is thickest below Buaraba Creek and gradually thins to the north away from the alignment of the surface water system. The analytical model does not represent the variable aquifer thickness across the site and is further considered to provide a conservative estimate of the groundwater inflow.

The existing irrigation bores surrounding the site have been identified by DNRM and through a bore census (Section 4.2). It has been identified that there is RN 129372, RN 129371, RN 59186, RN 143138, RN 143139 and RN 75118 which are located on the northern side of Buaraba Creek to the east of the site. These bores are located approximately 535 m, 865 m, 1,180 m, 2,675 m, 2,680 m and 2,875 m east of the site property boundary respectively. In addition to this, the bore census identified one unregistered irrigation bore (Burns Bore) some 125 m from the site property boundary and 300 m from the proposed pit.

These bores are all located within the potential (albeit conservative) radius of influence of the quarrying operations. The bore most likely to be affected by drawdown from the quarrying operations is the Burns Bore that is 150 m from the site property boundary. Under legislation (Section 84.3.d.11 of the Water Resource [Moreton] Plan 2007), the pit would be considered a replacement bore for the existing irrigation bores on the property, and as such it would need to be not located within:

50 m from a watercourse;

100 m of a boundary of a parcel of land; or

200 m of another water bore.

Figure 5.2 shows these buffer zones in relation to the property boundaries. The quarry will be able to operate within these licence conditions so as to minimise interference with the existing groundwater users. Buaraba Creek is the nearest watercourse, at its closest point it is 140 m from the proposed pit.

The proposed pit does encroach within the 100 m setback from two properties (Figure 5.2). Hy-Tec Industries run an existing quarry operation along the western edge of the site. There are no known groundwater bores located on this property and therefore does not use groundwater. Furthermore, any impact to the active pit would provide a benefit with increased drawdown in their pit.

The proposed pit will also encroach to within 100 m of the Burns property on the eastern edge of the site. As discussed in Section 4.2, groundwater at the Burns property is used only for stock and domestic purposes; with irrigation water sourced entirely from two water allocations from Atkinson Dam and from a private dam on the property. Therefore, drawdown in the alluvium will have no impact on their irrigation water supply.


The nearest bore outside the property boundary which targets the Buaraba Creek alluvium is Burns Bore (Figure 5.2). The bore is approximately 300 m from the proposed resource area, outside the 200 m buffer zone. Drawdown impacts at this bore (Burns Bore) are likely to be greatest when the pit is approaching, and in close proximity to the bore. Once the area has been quarried, the emplacement and presence of lower hydraulic conductivity material within the backfilled void would limit the hydraulic connectivity between the extraction pit and the bore, and hence limit the drawdown at the bore. By using the Marinelli and Niccoli (2000) equation presented in Section 5.1, a calculation of the maximum drawdown at this bore has been carried out. Table 5.3 presents the predicted drawdown at the existing alluvial bores when the east pit is in the southeastern corner of the property.

Table 5.3 Maximum drawdown at existing users

Bore Distance from proposed pit

(m)

K = 1 m/day

h0 = 12 m

K = 5 m/day

h0 = 12 m

K = 10 m/day

h0 = 12 m

K = 1 m/day

h0 = 6 m

K = 5 m/day

h0 = 6 m

K = 10 m/day

h0 = 6 m

Burns Bore 300 8.02 m 10.01 m 10.43 m 2.02 m 4.01 m 4.43 m

RN 129372 625 4.54 m 8.55 m 9.46 m 0 m 2.55 m 3.46 m

RN 129371 9,75 0 m 6.19 m 7.83 m 0 m 0.19 m 1.83 m

RN 59186 1,240 0 m 3.77 m 6.14 m 0 m 0 m 0.14 m

RN 143138 2,730 0 m 0 m 0 m 0 m 0 m 0 m

RN 143139 2,734 0 m 0 m 0 m 0 m 0 m 0 m

RN 75118 2,940 0 m 0 m 0 m 0 m 0 m 0 m

The steady state equation predicts that drawdown will occur at the Burns Bore, RN 129372, RN 129371 and RN 59186. However, the steady state equation is highly likely to over-predict the magnitude of drawdown at these bores and it can be seen that depending upon the assumptions used in the equation (eg. saturated thickness) this has significant influence on the drawdown predicted. The analytical predictions do not account for the following:

the transient and spatially variable nature of the quarrying operations;

fluctuations in groundwater levels;

thinning of the alluvial material to the north;

additional recharge provided by Buaraba Creek; and

backfilling of the pits with finer grained materials.

As a result of these additional influences on the groundwater system it is assessed that the steady state calculations are highly conservative and that the actual interference / drawdown on these nearby existing bores will likely be less than that predicted.


Water balance 5.3

The water balance of the pond / pit area was assessed for an approximate 50 year resource life and was based on the following assumptions:

i) The pond surface area for the extraction pits increases at the combined linear rate of 3.5 ha per year until it reaches a total of 20.2 ha.

ii) The pond surface area at completion of sand and gravel extraction will be 20.2 ha.

iii) Rejected fine material is not returned to the excavated void as backfill.

iv) Sand / gravel extraction at the rate of 260,000 m3/year.

v) Surface water runoff into the pit / pond will be encouraged – surface water runoff in sandy areas is often a low percentage of total annual rainfall. A conservatively low percentage estimate of surface water runoff (3% of total annual rainfall) has been used owing to the flat catchment area and the sandy nature of the area. The total catchment area was assumed to include the 936,000 m2 resource area.

vi) Water losses comprise water used for plant operation, evaporation from sediment traps, and dust suppression. This volume was estimated to be 10 ML/year.

The water balance was developed to allow for monthly variation in rainfall and evaporation. Average monthly climate data (Table 3.1) was used as water input / output variables. The monthly model calculates the potential volume of groundwater inflow into the pit / pond as a result of an overall net loss of pond water. The monthly water balance model results shown in Figure 5.3 indicate significant seasonal variation during each year. The seasonal variation results from the variation of evaporation that naturally occurs during the year as shown by the data in Table 3.1.

The trends illustrated on Figure 5.3 show that at early times of extractive operations the loss of water from the pit / pond will be minimal as the size of the pit grows. Once the pits have reached full extent, the groundwater losses from the system equilibrate and the seasonal influence of rainfall and evaporation are the main drivers of the monthly fluctuations.


Figure 5.3 Monthly groundwater loss

The graph shown in Figure 5.4 illustrates the cumulative volume of groundwater inflow required as input into the water balance over the length of the extraction period (assumed to be 50 years). The cumulative volume is equivalent to an annual groundwater entitlement of 175 ML/yr.

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

0 5 10 15 20 25 30 35 40 45 50 55

To

tal P

it/P

on

d A

rea

(m2)

Pit

/Po

nd

Mo

nth

ly W

ater

Lo

ss (

ML

/mo

nth

)Years

Groundwater Inflow/Loss (ML/month) (10 ML/yr Plant use) Water Licence Allocation (175 ML/yr)

Area Mined (m2) Lake Area (m2)


Figure 5.4 Cumulative groundwater deficit

The cumulative loss of water from the pit / pond is approximately 7,000 ML over the 50 year operational life. Figure 5.4 illustrates that a water licence of 175 ML/year should account for the water loss from the operation over the 50 year life.

It is important to reiterate that the water balance is conservative. It assumes that the excavated void will always intersect the groundwater table and that the groundwater level at the site remains constant. This is known not to be the case and as a result, the groundwater losses from the system as a result of the development are likely to be less.

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 100 200 300 400 500 600 700

ML

/m

on

thMonths

Cumulative groundwater deficit Water licence allocation


Water licensing 6

Groundwater resources within the proposed development footprint are managed under the Water Resource (Moreton) Plan 2007 and the Water Resource (Great Artesian Basin) Plan 2007. These water resource plans (WRP) are managed by DNRM and are discussed below.

Water Resource (Moreton) Plan 2007 6.1

The proposed development is located within the Brisbane River catchment. The catchment is covered by the Water Resource (Moreton) Plan 2007, which includes groundwater management within its objectives.

The area is located within the Lockyer Valley Groundwater Management Area and in particular Implementation Area #4, which includes the lower Lockyer Creek and Buaraba Creek. The WRP distinguishes between the various groundwater systems in the area, specifically the alluvial aquifers (groundwater unit 1) and hard rock aquifers (groundwater unit 2).

The Quaternary alluvium which is proposed to be extracted as part of the Project is classified as groundwater unit 1 within Implementation Area #4. The WRP states:

A person may not take groundwater in the Lockyer Valley groundwater management area other than:

a) for stock or domestic purposes; or

b) under a water entitlement or water permit; or

c) to allow monitoring or salinity control; or

d) under an authorisation under section 72.

Section 72 of the WRP states:

(1) An owner of land in implementation area 2, 3 or 4 who, on the commencement of this plan, is using an existing water bore on the land to take groundwater may continue to take groundwater using the bore.

(2) Subsection (3) applies if—

a) the chief executive is reasonably satisfied the outcomes mentioned in part 3 or the objectives of this plan are not being achieved; and

b) the resource operations plan does not state a process for granting, under section 212 of the Act, a water licence to replace an authority under subsection (1).

(3) The chief executive may, under section 212 of the Act, grant a water licence to the owner to take groundwater using the bore.

(4) The water licence must state an annual volumetric limit for the licence.

A meeting with Ashley Bleakley (Senior Technical Officer – DNRM, Nicci Window (Technical Officer – DNRM), AGE, and the proponent was held on the 7 February 2017. At the meeting it was confirmed that any existing water bore prior to implementation of the plan and used for irrigation or stock and domestic purposes did not require a licence under the WRP. The irrigation bores and stock and domestic bores identified within the site have been discussed in Section 4.2.


It is understood from discussion with DNRM that if the project were to proceed, a licence would be required. This licence would cover any groundwater removed from the Quaternary alluvium as part of extraction activities. The licence would have a volumetric limit associated with it which would include:

evaporative losses from the pit;

moisture content entrained within the quarried material; and

any water pumped from the pit to maintain reduced water levels.

The extraction pits would be treated as replacement bores to the existing Buaraba Creek alluvial irrigation bores that are currently constructed on the property. The alluvial licences would be associated with these pits.

The necessary information required by DNRM to process this licensing issue, including prediction of impacts (if any) to the existing users of the groundwater, is contained within this technical report.

Water Resource (Great Artesian Basin) Plan 2006 6.2

The proposed development is also located within the Great Artesian Basin (GAB) as defined by the Water Resource (Great Artesian Basin) Plan 2006. The project boundary is located within the Clarence Moreton Management Area and in particular the Gatton–Esk Road implementation area.

There are three management units within the Clarence Moreton Management Area, namely Clarence Moreton 1, 2 and 3. These units relate to the Walloon Coal Measures, Marburg Sandstone (Gatton Sandstone) and Helidon Sandstone (Woogaroo Sub-group) respectively.

It is understood that there are three irrigation bores within the project boundary (Figure 4.2) that are constructed within the Helidon Sandstone (Woogaroo Sub-group). The water licence for these irrigation bores can be converted into industrial use to allow for supplementation water supply for the quarrying operations.

Existing licences 6.3

DNRM license groundwater extraction under the provisions of the Water Act 2000. Three existing water licences are associated with the properties (Table 6.1). There are no volumetric limits attached to either licence, and the property owner is currently permitted to pump as per the individual licence conditions. As discussed in Section 6.1, irrigation bores within the Quaternary alluvium do not require licences under the WRP.

Table 6.1 Water licences

Licence No. Purpose Water Source Date of issue Expiry date

568006 Irrigation Clarence Moreton 3 management unit

(Helidon Sandstone) 27/05/2013 16/10/2019

104170 Water harvesting Buaraba Creek 6/05/2013 31/08/2020

31783G Irrigation and water

harvesting Buaraba Creek 3/05/2013 30/11/2019

From discussion with DNRM, the purpose of the existing Clarence Moreton 3 management unit (Helidon Sandstone) licence can be amended from its current purpose (irrigation) to the intended purpose (industrial) of the water supply. It was also recommended by DNRM that a volumetric limit should be applied to this licence at the same time the purpose is amended. The appropriate volumetric limit is determined by DNRM, however DNRM indicated that if the proponent had background hydrogeological information to assist DNRM with this determination it was suggested that this information was submitted.


Conclusions 7

The northern extraction pit will intersect sandstone material not associated with the Quaternary alluvium. The quarry will not intersect groundwater at this location and as such, no impacts are predicted for the Woogaroo Sub-group.

Excavation and dewatering of the two southern pits will lower the elevation of the water table of the Quaternary alluvial aquifer, forming a “cone of depression” around the pit. The cone of depression in the water table is predicted to extend some distance from the resource areas. However, the calculations conservatively assume the pits are at maximum depth and fully dewatered at all times. The pits will be backfilled with clay fines as extraction progresses, and therefore the extent and magnitude of impacts from the active quarrying area on the groundwater environment will be significantly less than is presented in this assessment.

Furthermore, the main recharge mechanism to the Quaternary alluvium is from Buaraba Creek which has not been accounted for in the analytical equation. Any streambed recharge through the bed of Buaraba Creek will act to buffer the extent of drawdown in the Quaternary alluvium.

The proponent currently holds water licences to take water from Buaraba Creek and the Clarence-Moreton 3 Management Unit which represents the Woogaroo Sub-group sediments. Existing irrigation bores in the Buaraba Creek alluvium are not required to be licensed and it is understood from discussions with DNRM that the take of groundwater predicted from the proposed development (175 ML/yr) can be substituted for this existing irrigation take. The alluvial extraction pits would be considered as replacement alluvial irrigation bores on the property.

A requirement under legislation (Water Resource [Moreton] Plan 2007), states that the pit (replacement bore) should not be located within 100 m of a boundary of a parcel of land. Although the proposed resource area does not meet these criteria, the two relevant properties (Hy-Tec Industries and Burns) do not use groundwater for any purpose other than stock and domestic supply and therefore the impact to their use will be minimal.

Drawdown impacts at Burns Bore are likely to be greatest when the pit is approaching, and in close proximity to the bore. As the active extraction area moves away from the property boundary the impacts will reduce. The final voids will be located within the central portion of the site, away from the Burns Bore or the site boundaries.

The proponent intends to maintain dry pits where possible; where this is unavoidable the size of surface ponding will be kept to a minimum to reduce the groundwater take from evaporation. The predicted maximum groundwater inflow into the pits has been presented for the Quaternary alluvium, and the Gatton Sandstone (Table 5.2). Groundwater inflows from the Gatton Sandstone are very low and depressurisation in this unit would not be measurable. As stated above, the calculations assume the pits are at maximum depth and fully dewatered at all times which will not be the case.

Most of the sandstone bores at the site and surrounds target the underlying Woogaroo Sub-group. The Gatton Sandstone separates the Woogaroo Sub-group from the Quaternary alluvium. The groundwater levels from the Gatton Sandstone and Woogaroo Sub-group show similar long-term trends which correlate well to climatic variations. However, the groundwater quality of the two units is distinct suggesting the interconnection between the two units is poor. Therefore, the nearby landholder bores which screen the Woogaroo Sub-group are not predicted to be impacted by the extraction of the alluvial material.

Given the presence of two DNRM groundwater monitoring bores within the site (RN 14320619 and RN 14320618), it would be considered worthwhile to negotiate with DNRM to enable monitoring of these existing facilities. This would allow the proponent to gather groundwater level data and monitor impact (or otherwise) to the Buaraba Creek alluvium from the resource extraction and proposed development.

Australasian Groundwater and Environmental Consultants Pty Ltd

Groundwater Impact Assessment, Rocky Gully Road, Coominya (G1729A) | 33

References 8

Australian and New Zealand Environment and Conservation Council (2000), ‘Australia and New

Zealand Guidelines for Fresh and Marine Water Quality’, Volume 1, ISBN 09578245-0-5

Australasian Environmental & Groundwater Consultants (2000) ‘Groundwater impact assessment of

proposed sand extraction, Buaraba Creek, Coominya’, Project No. G1078, June 2000

Australian Government, Bureau of Meteorology, (2016), ‘Groundwater Dependent Ecosystem Atlas’,

accessed 5th January 2017

FAO (2013) Food and Agricultural Organisation of the United Nations:

http://www.fao.org/docrep/t0667e/t0667e05.htm.

Department of Environment and Heritage Protection (2009) ‘Queensland Water Quality Guidelines’,

Version 3, ISBN 978-0-9806986-0-2

Department of Environment and Resource Management, (2010), ‘Lockyer Creek environmental values

and water quality objectives, basin No. 143 (part), including all tributaries of the creek’, prepared by

Water Quality & Ecosystem Health Policy Unit, July 2010

Department of Natural Resources and Mines (2016) ‘QLD globe - soils’,

https://www.business.qld.gov.au/business/support-tools-grants/services/mapping-data-

imagery/queensland-globe

Ellis R. (1999). ‘Water quality deterioration in alluvial aquifers’. LWRRDC Project QP130. Final Report.

Queensland Department of Natural Resources, Brisbane.

Geoscience Australia (2017) ‘Clarence-Moreton Basin’, [ONLINE] Available at:

http://www.ga.gov.au/scientific-topics/energy/province-sedimentary-basin-

geology/petroleum/onshore-australia/clarence-moreton-basin [Accessed 3 January 2017]

Marinelli and Niccoli, (2000), ‘Simple Analytical Equations for Estimating Groundwater Inflow to a Mine

Pit’, Vol 38, No. 2 - Ground water – March-April 2000 (pages 311-314)

New Hope Coal Australia (2014) ‘New Acland Coal Stage 3 project’s Environmental Impact Assessment,

Chapter 6 - Groundwater resources’, January 2014

The State of Queensland (2016) ‘Groundwater Database - Queensland’,

https://data.qld.gov.au/dataset/groundwater-database-queensland

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