Section 3.7 Groundwater

Abbot Point Coal Terminal 0 EIS • Adani

Terminal 0 Environmental Impact Statement


Terminal 0 Environmental Impact Statement 3-171

3.7 Groundwater This section describes the existing groundwater regime within the Project area, including aquifers and beneficial uses (environmental values). Predicted changes to the existing groundwater regime and potential impacts to environmental values are discussed in this section with specific technical information provided in Appendix E2 – Groundwater Technical Report. In accordance with the published EIS Guidelines for the Project, mitigation and management measures presented in this section are in accordance with relevant Commonwealth requirements for potential impacts on MNES and Queensland Department of Environmental Heritage and Protection (EHP) guidelines regarding water.

3.7.1 Queensland Legislation

3.7.1.1 Water Act 2000

The Water Act 2000 (Water Act) provides for the planning, protection, allocation and use of Queensland’s surface waters and groundwater. A person must not take, supply or interfere with water unless authorised under the Act. Under the Water Act, Water Resource Plans (WRP) and Resource Operation Plans (ROP) are subordinate legislation that administer the taking of water and regulate environmental flows. Currently, there is no WRP for the Project area. Groundwater in Queensland is managed through the establishment of groundwater management areas under a WRP or, for the Abbot Point area, under the Water Regulation 2002. An authorisation is required to access groundwater and/or construct works to take groundwater for certain purposes. The taking or interfering with groundwater is managed differently across the state depending on the location and type of groundwater. Section 3.1 – Legislation, Land Use and Planning presents an overview of water related developments and the activities likely to require approval under the Water Act for the Project.

At the planning stage, EHP requires that a proponent carry out a groundwater investigation to assess the impacts of the Project on groundwater. This includes collecting and assessing groundwater data (usually at a local scale and specific to their proposed activities). In this assessment process, EHP considers this data in the context of the entire water resource system and all potential impacts.

3.7.1.2 Environmental Protection Act 1994

The object of the Environmental Protection Act 1994 (EP Act) is to “protect Queensland’s environment while allowing for development that improves the total quality of life, both now and in the future, in a way that maintains ecological processes on which life depends” (s3). Of the five pieces of subordinate legislation under the EP Act (see Section 3.1 – Legislation, Land Use and Planning), the Environmental Protection (Water) Policy 2009 applies directly to groundwater.

3.7.1.3 Environmental Protection (Water) Policy 2009

This policy applies to all water in Queensland and provides a framework for defining the environmental value of water and guidelines for water quality. The Environmental Protection (Water) Policy 2009 (EPP (Water)) is subordinate legislation under the Environmental Protection Act 1994 (EP Act). The purpose of this policy is achieved through:

Identifying environmental values and management goals for Queensland waters;



Stating water quality guidelines and water quality objectives to enhance or protect the environmental values;

Providing a framework for making consistent, equitable and informed decisions about Queensland waters; and

Monitoring and reporting on the condition of Queensland waters.

3.7.2 Method

To provide a comprehensive groundwater assessment, background groundwater quality and groundwater levels were determined during two separate monitoring rounds in April and June 2012, respectively. In order to comprehensively assess the existing groundwater environment and predict the likely impacts to groundwater from the development of this project, the following tasks were undertaken:

Review of geological, stratigraphy, rainfall, borehole, water quality and water level data relevant to the Project area;

Field investigations at the Project site to conduct aquifer hydraulic tests and groundwater sampling in order to determine site-specific hydraulic conductivity and groundwater characterisation;

Development of a three-dimensional finite difference (numerical) groundwater model for the Project site using the MODFLOW 2000 modelling code;

Calibration of the groundwater model against water level data collected during groundwater investigations at the Project site; and

Model simulations incorporating the proposed development plan to assess the impact and influence of construction and operational activities on groundwater at the Project.

3.7.2.1 Field Method

Two groundwater investigation programs were undertaken specifically to assess the existing groundwater conditions within the Abbot Point region and for the Project. The first groundwater investigation program was conducted between 23 and 28 April 2012, and the second one was undertaken between 3 and 8 June 2012.

The bore sampling plan is shown in Figure 3-42. A total of seven bores (125268, 125269, BH307, BH315, BH316, BH327 and 125272) were sampled. Pump and slug tests were completed on two bores (BH316 and BH327), and Level TROLL pressure transducer water level loggers were installed permanently in these two bores for the purposes of ongoing water level monitoring (GHD 2012).

Proposed T0 StockpilesEx

isting

T1

Proposed T0 MOF

BH314BH335

BH332

BH330

BH327

BH316

BH315

BH305

BH307

54547

54548

125272

CPT210CPT209

125270

CPT235

125269

125268CPT245

125273

CPT256

CPT206

148°6'0"E

148°6'0"E

148°5'0"E

148°5'0"E

148°4'0"E

148°4'0"E19

°53'0"

S

19°53

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LegendRoadProposed Road EasementExisting RailProposed CommonRail Corridor

APSDA BoundaryProject AreaGBRMP BoundaryDirectory of Important WetlandsWatercourse

Groundwater BoreWater quality samplingHydrogeology

WetlandsPalustrineEstuarine

0 250 500125

Metres

CAIRNS

BRISBANE

MOUNT ISATOWNSVILLE

ROCKHAMPTON

Data source:Roads by Geoscience Australia; Terminal data by Adani; Aerial Imageby BingMaps, 2011, All other data by DERM, 2010.

Job: B12705_084-R1_GWboresDate: 7/06/2013

DISCLAIMERCDM Smith has endeavoured to ensure accuracy andcompleteness of the data. CDM Smith assumes no legal liability orresponsibility for any decisions or actions resulting from theinformation contained within this map.

Abbot Point Coal Terminal 0 (T0) ProjectFigure 3-42 Groundwater Bore Sampling Plan



Bore holes were gauged using an electronic interface probe to measure and record the standing water level (SWL). All bores selected for monitoring were purged (with approximately three bore volumes of water removed) and until water quality parameters stabilised.

Field parameters including temperature, electrical conductivity (EC), dissolved oxygen (DO), and pH were measured and recorded during purging activity using a calibrated YSI Quatro Plus water quality meter. Sampling was completed using a peristaltic pump under low flow.

Field intra- and inter-laboratory duplicates were prepared by collecting discrete groundwater samples at a rate of one per 10 primary samples and one per 20 primary samples respectively. Samples for duplicate analyses were generally selected from monitoring well locations with the highest probability of containing contaminants of concern based on field observations of odour, sheen or any unusual groundwater colour or turbidity.

Further information on the method, sample handling and preservation and equipment calibration is detailed in Appendix E2.

3.7.2.2 Model Development

Specific features included in the groundwater model for the Project include Mount Roundback to the south, the Caley Valley Wetland in the centre, Mount Luce to the north west and T0-T3 to the north east. The Caley Valley Wetland was nominated as MODFLOW RIVER cells to allow these areas to interact with groundwater in surrounding cells. Water levels in the Wetland were set at 0 m AHD, based on an assessment of contours. Hydrogeologic features included in the groundwater model include the shallow sandy aquifer and weathered bedrock aquifer within the Abbot Point region. Figure 3-43 shows the hydrogeologic features represented in the model, noting these are not to scale and for representative purposes only.

Figure 3-43: Features included in the Model

The groundwater model was calibrated to simulate actual conditions. Calibration included the use of boundary conditions and additional inputs/outputs that were assumed (based on topography and water level data) to affect groundwater flows.

South

North

Mount Roundback

Bedrock (No hydraulic conductivity,

No-flow boundary)

Caley Valley Wetland

T0 Project

Area

Weathered Bedrock

K = 5 m/day

Sandy Clay K = 0.5 m/day

Sand K = 2 m/day



3.7.2.3 Model Calibration and Scenarios

Due to the limited amount of site specific data available, the model was calibrated only in steady state mode. Steady state model calibration involved the matching of hydraulic heads under steady state conditions to water levels observed at the site. Model calibration, modelling scenarios and groundwater level scenarios are further discussed in Appendix E2.

3.7.2.4 Evapotranspiration and Recharge

In MODFLOW 2000, evapotranspiration is defined as a discharge from groundwater that is inversely proportional to the depth from ground surface to the water table. The inputs required to define evapotranspiration in the model are the maximum evapotranspiration rate, which is based on the evaporation rate for the area, and an extinction depth. The rate of evapotranspiration in a given cell at a given time is then calculated by linear interpolation between the maximum evapotranspiration rate when the water table is at the ground surface, to an evapotranspiration rate of zero when the water table is at (or below) the extinction depth.

Evapotranspiration data was derived from daily rainfall data for the Abbot Point area from January 1889 to June 2012. A maximum evapotranspiration rate of 1890 mm/year was entered into the model, which corresponds to approximately 95% of the average yearly evaporation rate derived from SILO. An extinction depth of 2 m was also used in the model.

Diffuse recharge is estimated as a percentage of precipitation (Waterloo Hydrogeologic Inc 2005). This percentage ranges from 5% to 40% depending on many different factors including land use, vegetation type, surface topography (slope), and soil cover material. As there are no detailed recharge studies at the Abbot Point site, this crude approach (e.g. recharge as a percentage of precipitation) was used to provide an initial estimate to use in the groundwater model. Therefore, diffuse recharge at the site can range from about 52 mm/year (5% of precipitation) to about 415 mm/year (40% of precipitation).

3.7.2.5 Boundary Conditions

Boundary conditions for the model were defined by the groundwater head results from the current groundwater monitoring event. The boundary conditions for the model were defined by assigning constant head cells at the coastline of the northern area of the model extent to be 0 m AHD, and all cells to the north of the coastline were made inactive as they do not take part in the groundwater flow regime for the site. Also, constant head cells were assigned at the eastern, southern and western boundaries of the model domain, with head values defined by the results of the current groundwater monitoring event under steady state conditions. The values were determined by assigning the hydraulic head results under steady state conditions to the corresponding boundaries of the model domain. It is noted that hydraulic head results from June 2012 used as constant heads were representative of the lowest groundwater levels during the driest season of the year. Therefore, the constant head conditions were based on worst case scenarios of specific groundwater modelling events, which can increase up to 2 m over the wettest seasons of the year. However, due to the exceptional wet period experienced across the region in the last two years, groundwater level fluctuations are currently at maximum historic levels and are unlikely to continue to increase, so will remain at least 2 m below the base of the Project stockyard platform levels.

3.7.2.6 Hydraulic Conductivity

Water level data recorded on the data logger for the falling and rising head slug tests was analysed using Theis, Neuman, Theis with Jacob Correction and Hvorslev methods to determine hydraulic



conductivity. Copies of the analysis sheets are included in Appendix E2, and hydraulic conductivity values determined for each pump and slug test are summarised in Table 3-47. A minimum of two falling head and two rising head tests were conducted at each bore.

Table 3-47: Hydraulic Conductivities

Groundwater Monitoring Bores Screened in Sand

Bore Number

Pump Test (m/day) Slug Test (m/day) Drawdown Recovery Falling Head Test Rising Head Test

Theis Neuman Theis with Jacob Correction

Thies Recovery Hvorslev C-B-P Hvorslev

Bouwer and Rise

BH316 2.06 4.09 2.08 2.23 Unreliable Data Set 1.49 1.07 BH327 1.40 2.08 1.41 1.23 1.09 2.51 3.86 2.97

Average 2.19 1.73 1.80 2.35 Adopted Average Hydraulic Conductivity for Sandy Layer: 2 m/day

3.7.3 Existing Environment

3.7.3.1 Site Conditions

Weather conditions were generally dry during both groundwater investigation programs. Tidal conditions during both investigation programs were low in the morning and high in afternoon.

3.7.3.2 Vegetative Cover and Access to Bores

The Project area is dominated by sparse, low lying vegetation, particularly where most groundwater monitoring bores are located. However, a small portion of the Project area to the north east is covered by thick vegetation (both remnant and regrowth), which obscured the visibility of monitoring bores. In some areas to the south and west, creeks and thick, tall vegetation made access difficult to some sites. The sites located within the adjacent T1 facility were generally open, easily accessible and usually surrounded by low lying grasses, at either the side of a road or along access points. This was more reflective of an operating coal stockyard.

Section 3.11 Terrestrial Ecology provides a comprehensive description of the vegetation communities at and adjacent to the Project area.

3.7.3.3 Topography

A digital elevation model with 1 m grid resolution over Queensland’s Whitsunday Regional Council (Local Government Area) was generated from ground point LiDAR data obtained from EHP via NQBP. The Airborne Laser Scanning (ALS) 1 m interval point data has vertical and horizontal accuracies of 0.1 m and 0.3 m respectively. The survey was carried out between 10 June 2009 and 17 June 2009. Data processing was undertaken using a ground algorithm to automatically classify and separate ground points from non-ground points.

The topography of the Abbot Point region consists of coastal sand dunes and mud flats lying at elevations below 5 m Australian Height Datum (AHD) and abrupt granitic hills - Mount Luce and Mount Roundback have peak elevations of approximately 300 m AHD and 700 m AHD, respectively.



3.7.3.4 Surface Water

The dominant hydrological feature of the area is the Caley Valley Wetland, which has been listed as a Nationally Important Wetland under the Commonwealth Directory of Important Wetlands. During the wet season, the Wetland can cover an area of approximately 5,154 ha. On a seasonal basis, the Wetland retreats to a small lake (Lake Caley) and can become completely dry during drought (BHP Billiton 2011). The wet season of 2012 was atypical.

The total catchment draining into the Wetland is approximately 830 km2 (including Saltwater Creek) and includes portions of Mount Roundback and Mount Little immediately to the south. Spring, Splitters, Tabletop, Main and Mount Stuart Creeks drain into Curlewis Bay to the northeast, whilst Six Mile, Goodbye and Saltwater Creeks drain into the Caley Valley Wetland area. Section 3.6 Surface Water and Hydrology provides a detailed description of the water quality and surface water features of the Project area and adjacent sites.

No major or minor watercourses exist within the Project area. Surrounding water bodies are described as ephemeral and generally only support flows following intense or prolonged periods of rainfall. During the winter field study, Saltwater Creek contained flowing water (refer Section 3.6 Surface Water and Hydrology).

To the south west of the Project area, watercourses upstream of the Wetland are described as lowland freshwater creeks (as per the ANZECC/ARMCANZ Guidelines). These are generally small, shallow streams (<10 m in width) with sandy soils and sediments, and sparse riparian areas dominated by wetland flora species. The water bodies within the Abbot Point area are likely to provide drinking water for cattle and native fauna, and are too small to be used recreationally by humans. There is no standing surface water directly within the Project area.

3.7.3.5 Geology

The Australia 1:250,000 Geological Series – Ayr Sheet SE 55-15 (Paine et al. 1968) states that the geology in the Abbot Point and Wetland region is comprised primarily of Quaternary coastal mud flats (Qm) with marginal coastal sand dunes (Qr) and some minor deposits of outwash and talus (Figure 3-44).

Upper Carboniferous to Late Permian aged deposits of mafic intrusive igneous rocks (C-Pd) intercept the coastal sand dune formations at the tip of Abbot Point (Bald Hill) and wind down the coast to Mt Luce, west of the APSDA. These units comprise diorite, quartz diorite, tonalite, gabbro, norite and minor granodiorite, adamellite and granite. South of Mt Luce and throughout the southern and south western parts of the Wetland region are the Quaternary coastal mud flats.

Further south of the Wetland area is an area of Alluvial and deltaic deposits (Cza) and beyond this region to the South and leading up to Mt Roundback are formations of adamellite, granite, some granodiorite and minor fine-grained variants (C-Pg) which make up the Hectate Granite formation which surrounds the area to the north of Bowen (Connell Hatch 2009).

Based on a review of the borehole logs from previous investigations (Connell Hatch 2009) the following information on geological profiles was compiled.

Existing Jettyand Wharf

Proposed T0

Exist

ing T1

Proposed T0 Berth

Proposed T0 Jetty

Proposed T0 MOF

Qm

Qr

Qr

C-Pd

Qu

Qr

C-Pd

C-Pd

C-Pd

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148°7'0"E

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°51'0

"S

19°5

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19°5

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19°5

6'0"S

LegendRoadExisting RailProposed Road EasementProposed CommonRail Corridor

APSDA BoundaryGBRMP BoundaryProject Area

0 500 1,000250

Metres

CAIRNS

BRISBANE

MOUNT ISATOWNSVILLE

ROCKHAMPTON

Data source:Geoscience Australia; Terminal data by Adani; Aerial Image byBingMaps, 2011.

Job: B12705_011-R2_SurfaceGeollDate: 24/01/2013

DISCLAIMERCDM Smith has endeavoured to ensure accuracy and completeness ofthe data. CDM Smith assumes no legal liability or responsibility for anydecisions or actions resulting from the information contained within thismap.

Abbot Point Coal Terminal 0 (T0) ProjectFigure 3-44 Surficial Geology of the Project Area and surrounds

Outwash and talusCoastal mud flatsCoastal sand dunesDiorite, quartz diorite, tonalite, gabbro, norite; minor granodiorite, adamellite and graniteC-Pd

QmQr

Qu



Sand

Sand is moist and pale yellow typically at 0.3 m below the surface, although where established scrub is present, the sand was commonly found to be dry and friable down to depths of 1 m due to the moisture take-up by the vegetation and enhanced evapotranspiration (Connell Hatch 2009). This effect was more noticeable in areas with established trees. Across the Connell Hatch study site, the sand thickness varied from 0.6 m to 1.2 m (Connell Hatch 2009).

Sandy Clay

A sandy clay to clayey sand layer of low to intermediate plasticity is situated beneath the surface sand and is distinct from the sand layers above and below due to the presence of clay (Connell Hatch 2009). The sandy clay and clayey sand units differ by their relative percentages of clay and sand which was determined by local environmental conditions at the time of deposition (Connell Hatch 2009).

Weathered Bedrock

These units were described as dark grey in colour, fine to coarse grained with an igneous fabric texture. The units were extremely low strength with fine to medium angular gravel and were highly fractured. A generally clay/silty clay matrix-supported rock was observed at lower depths to be clast-supported. This weathered rock is saturated and soft.

Bedrock

These units were described as dark grey, fine grained, massive structures of a very high strength and are intensely to highly fractured on sub-horizontal and sub-vertical joints, irregular and planar with iron stains.

3.7.3.6 Climate

In order to provide a comprehensive description of climate conditions at the Abbot Point site, synthetic weather data (1889-2012) for this location (148.05°E, 19.9°S, 187 m) was extracted from SILO (Queensland Government 2012). The data extracted includes synthetically generated records for daily precipitation, temperature, and evaporation and is based on actual weather data from nearby stations. Based on these data, the average annual precipitation at the Abbot Point site is about 1037 mm/year. The wet season is from December to March with average monthly precipitation values of almost 250 mm/year, and the dry season is from July to October with average monthly precipitation typically less than 50 mm/year. Daily temperature at the Abbot Point Site fluctuates between 7.9°C and 34.5°C. However, monthly average temperature fluctuates between 18°C (July) and 27°C (December - February). Evaporation at the site stays relatively high throughout the year ranging from 99 mm/month to 210 mm/month. Figure 3-45 summarises these results.

Climate data has been further summarised in Section 3.2 Climate, Natural Hazards and Climate Adaptation.



Figure 3-45: Monthly average precipitation, temperature, and evaporation for the Abbot Point site (148.05°E, 19.9°S, 187 m) based on synthetic weather record (1889-2012)

3.7.3.7 Evapotranspiration

The Potential Evapotranspiration (PET) has been previously estimated using a variety of methods and intermediary datasets (Jolly et al. 2011). Further information on evapotranspiration is available in Section 3.2 Climate, Natural Hazards and Climate Adaptation and in Appendix E2.

3.7.3.8 Recharge

Specialised Information for Land Owners (SILO) is an enhanced climate data bank hosted by the Queensland Climate Change Centre of Excellence (QCCCE). It interpolates data between observation stations based on historical climate data from the Bureau of Meteorology (BoM). Based on the review of rainfall data derived from SILO, it is considered that evaporation tended to exceed precipitation throughout the year except for the months of January and February during which the highest rainfall of the year occurs. These two months are likely the most important for aquifer recharge and may occur as a combination of diffuse recharge (infiltration and percolation of rainfall) and from stream interactions with the groundwater system.

This analysis is complemented with an estimate of recharge for a small area (<1.6 ha) about 8 km south of Abbot Point calculated using the Method of Last Resort (Jolly et al. 2011). This estimate resulted in maximum recharge value of about 14% of precipitation. The most conservative estimate is considered to be 20% of precipitation because recharge estimates at similar sites near the coast of Queensland are usually in the 14%-26% range. According to this, the aquifer system would receive approximately 208 mm/year as diffuse recharge from the surface. Consequently, this recharge was used during calibration of the steady state mode to effectively simulate hydraulic heads observed at the site.

0.0

5.0

10.0

15.0

20.0

25.0

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

Tem

pera

ture

(°C)

mill

imet

res

Precipitation (mm/month) Evaporation (mm/month) Temperature (°C)



3.7.4 Modelling

3.7.4.1 Groundwater Modelling Objectives

The objectives of the baseline groundwater modelling work were to:

Define the commencement date, duration, anticipated quantity and frequency of development activities;

Carry out a baseline assessment of the receiving environment (before development), including seasonal variability of water flow, if applicable;

Determine the radius of influence and profile of the Project; and

Identify further groundwater investigations that might be required to refine this baseline groundwater model.

3.7.4.2 Hydrogeological Conceptualisation

A conceptual hydrogeological model was developed by taking into account previous studies (GHD 2012), new data, and field information collected for the Project. The model was used to develop a numerical groundwater model depicting baseline conditions and development scenarios. The following information was reviewed to better understand the relationship and interaction between groundwater and hydrogeologic features in the local area:

Connell Hatch, 2009: Geotechnical Investigation Report, Abbot Point Bulk Coal Terminal X80/X110 Expansion. Report H6000-80-GEO-GT06-002/01 prepared for the Ports Corporation of Queensland; and

EHA Pty Ltd, 2005a: Abbot Point Expansion. Baseline Groundwater Monitoring Investigation Report. Report GW-05-16-REP-002 Rev 0 prepared for WBM Oceanics Pty Ltd.

Where data was available from the field investigations completed in April and June 2012, these were utilised as much as practicable. The next most reliable data that was utilised was the Connell Hatch (2009) report as this included borehole logs and geotechnical logs that gave insight into the subsurface across the Project area. Third to be utilised were the EHA (2005b) reports which provided borehole and monitoring bore installation information for several of the boreholes around the Project area.

The hydrogeological conceptualisation and relevant cross-sections are summarised in Appendix E2.

3.7.4.3 Numerical Model Development

A numerical groundwater model for the Project area was developed in the Visual Modflow software using the MODFLOW 2000 modelling code (Harbaugh et al. 2000). The model was adapted from a model built previously for a related study, with appropriate authorisation.

The Project groundwater model domain was defined by focusing the original Abbot Point model (developed for the Abbot Point CIA) for the Project area. The model grid and extent are shown in Figure 3-46.



Figure 3-46: Project Groundwater Model Domain 3.7.4.4 Model Parameters

Site specific values for hydraulic conductivity were calculated from field tests undertaken around the Project area. Appendix E2 summarises the aquifer properties used in the model.

3.7.4.5 Hydraulic Conductivity

Hydraulic conductivity values imported into the model were determined from aquifer pump and slug test data collected from bores BH316 and BH327 during April and June 2012. Pump and slug tests were undertaken using the general procedures described in Sub-section 3.7.2.6.

The hydraulic conductivity values determined for each borehole and for each slug test were consistent, and the average value of 2 m/d was used as input for hydraulic conductivity in the groundwater model.

3.7.4.6 Groundwater Quality Assessments – Investigation Levels

The ANZECC/ARMCANZ (2000) "Australia and New Zealand Guidelines for Fresh and Marine Water Quality" provide guidance to assess water quality in aquatic ecosystems. These guidelines stipulate that the identification of the receiving environment or the likely beneficial use of the water is essential for selecting the most applicable criteria.

N

Inactive Cells

T0 Project

Area

Caley Valley Wetland

Constant Head Boundary



Groundwater across the region flows radially from the base of Mt Roundback towards Abbot Point, with some discharge into the Wetland. The measured groundwater salinity (indicated by Electrical Conductivity) at the site exhibited noteworthy variability, which suggests some surface/groundwater interaction. The receiving waters for the Project area are likely to be the Wetland, which is a Freshwater or brackish water Aquatic Ecosystem; however it is important to note that with tidal inundation, the ecosystem can become estuarine. In ANZECC/ARMCANZ (2000), the Estuarine Aquatic Ecosystem is a sub-set of the Marine Aquatic Ecosystem. However, there are no Estuarine criteria for the main parameters of concern so it is necessary to adopt the Marine values. In the absence of Marine values it is common practice to refer to Fresh water criteria to at least provide some sort of benchmark for comparison purposes. Consequently, results of the groundwater monitoring will be compared with both the marine and freshwater trigger levels within the ANZECC/ARMCANZ (2000) guidelines. Due to the likely ultimate receiving environment, trigger values with a high level of species protection 95%, have been adopted.

It is noted that some of the trigger levels for various analytes for environments presented in ANZECC/ARMCANZ (2000) are currently less than the laboratory detection limits. Consequently, it was considered that the laboratory detection limit is suitable for use as a screening value for concentrations of analytes in groundwater where trigger values provided in ANZECC/ARMCANZ (2000) cannot be applied. It is noted that the ANZECC/ARMCANZ (2000) criteria do not endorse an accepted trigger value for Total Petroleum Hydrocarbons (TPHs), the majority of volatile organic compounds (VOCs), and major anions and cations due to their large variability across regions.

The applicable criteria for the Project area are the ANZECC (2000) fresh and marine water 95% trigger levels.

3.7.4.7 Field Parameter Results

Field parameters for groundwater were measured spatially and temporally over two periods; 23-28 of April 2012 and 3-8 of June 2012. The field parameters were collected after purging approximately three bore volumes. Three readings were collected unless the parameters did not stabilise in which case further parameter readings were collected. Field parameters measured included Dissolved Oxygen (DO), Electrical Conductivity (EC), pH, Redox potential and temperature. These parameters are presented in Appendix E2.

3.7.5 Potential Impacts

Based on the above baseline groundwater assessment and preliminary steady state model simulations, there are a number of potential impacts on groundwater conditions associated with the Project.

Time series data from across the perimeter of the T1 facility and the Project area indicate tidal influences in groundwater elevations of up to approximately 1 m. Based on this it can be assumed that there is likely a mixing zone extending from the sea to the Project area and groundwater flow will be tidally impacted.

The highly variable measured electrical conductivities across the perimeter of the T1 facility and the Project area indicate that a series of complex interactions are occurring. Surface waters are too fresh and are unlikely to be significantly impacted by saline groundwater. In addition, the low salinities observed in selected bores close to the coast, indicate that there is likely some localised freshwater recharge taking place. The saline water recorded in other bores indicates that a certain degree of confinement limiting the amount of fresh recharge to these units.



Groundwater levels are below the base of the Project stockyard platform levels. Therefore, the construction of these structures is unlikely to impact upon the normal groundwater flow and levels during the driest seasons of the year. Although seasonal groundwater level fluctuations can be expected to rise up to 2 m bgs (i.e. 4 m AHD) no impacts on surface water can be expected across the Project area during the wettest seasons. Due to the exceptional wet period experienced across the region in the last two years, groundwater level fluctuations are currently at maximum historic levels and are unlikely to continue to increase, so will remain at least 2 m below the base of the Project stockyard platform levels.

3.7.6 Mitigation and Monitoring Measures

3.7.6.1 Mitigation Measures

The following mitigation and monitoring measures are proposed to ensure that potential impacts to groundwater are minimised and in order to prevent or minimise environmental and human health impacts.

Establish baseline groundwater conditions and mitigation measures through:

Hydrogeological conceptualisation and prediction of groundwater conditions using numerical modelling;

Preparation and implementation of a construction groundwater management plan (CGMP) to outline environmental management practices and procedures to be followed during construction of the project, including dewatering activities that are likely to be required during excavations for infrastructure plan;

Manage construction activities that have a potential to impact groundwater quality, as follows:

− Control surface water flows, drainage and erosion by the implementation of a surface water management plan. The existing stormwater return dam will avoid runoff to environmental receptors (waterways) and will minimise any likely impacts on groundwater quality

− Fuels and chemicals are stored adequately (e.g. bunds and shelter) and MSDS for each chemical is maintained on-site

− Develop and implement construction and operational management plans for the Project coal stockyard

3.7.6.2 Monitoring Measures

The following monitoring measures are designed to monitor groundwater quality conditions before, during and after construction and to ensure potential impacts to groundwater quality are addressed effectively. The monitoring measures include:

1. At least one groundwater monitoring event before, during and after construction; and

2. Monitoring groundwater quality and implementing a suitable groundwater monitoring network. This would include the use of existing bores, as shown in Figure 3-42.



3.7.7 Commitments

Adani commits to undertaking the following actions to protect and enhance the groundwater environmental values:

Hydrogeological monitoring where activities are likely to cause localised lowering of groundwater levels;

Site investigation and monitoring - Site investigation and monitoring to determine contaminants of concern, contaminant concentrations, contaminant sources and hydraulic properties of key aquifers;

Construction groundwater management plan - To outline environmental management practices and procedures to be followed during construction of the Project, including for dewatering activities that are likely to be required during excavations for deep infrastructure such as for the dump-station vault;

Manage construction activities to avoid impacts on groundwater - Implementation of a surface water management plan;

Monitoring groundwater quality and implementing a suitable groundwater monitoring network - To monitor groundwater quality conditions before, during and after construction and to ensure potential impacts to groundwater quality are addressed effectively; and

Regular auditing will be undertaken for erosion and sediment control measures, surface water diversion methods and groundwater quality analysis to determine effectiveness of the adopted mitigation methods.


Terminal 0 Environmental Impact Statement

Section 3.7 Groundwater - Amazon...

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Transcript of Section 3.7 Groundwater - Amazon...