Victorian Mallee Irrigation Region

Standards/Guidelines for

Installation and Management of

Testwells and Piezometers

17

Appendix 2

Enhancement of the Irrigation Development Guidelines in the Mallee - Standards for Testwells

Implementation of the Mallee Regional Irrigation Development Guidelines – 2010/11

Contract number: 10/893

Prepared for: Mallee Catchment Management Authority

Regional Sustainability

Prepared by: Scott McLean

Mallee Irrigation Development Coordinator

DPI, Farm Services Victoria, Mallee

Telephone 03 5051 4500

Email scott.mclean@dpi.vic.gov.au

If you would like to receive this information/publication in an accessible format (such as large print or audio) please

call the Customer Service Centre on 136 186, TTY 1800 122 969, or email customer.service@dpi.vic.gov.au

Published by the Department of Primary Industries Sustainable Landscapes, Mallee, June 2011

© The State of Victoria 2011.

This publication is copyright. No part may be reproduced by any process except in accordance with the

provisions of the Copyright Act 1968.

Authorised by the Department of Primary Industries

1 Spring Street, Melbourne 3000.

Disclaimer

This publication may be of assistance to you but the State of Victoria and its employees do not guarantee

that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and

therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any

information in this publication.

For more information about DPI go to www.dpi.vic.gov.au or phone the Customer Service Centre on 136 186.

Introduction and Purpose

Background

Mallee Land and Water Management Plan

Formation of Salinity Management Plans to Irrigation Development Guidelines

Unbundling and Minister’s Determinations, June 2007

Purpose of Standards/Guidelines for Groundwater Monitoring

Why monitor Groundwater

Groundwater monitoring and salt management in the Victorian Mallee

Meeting the Water-Use Objectives

The use of Soil Surveys and IDMP’s to Determine Monitoring Requirements

Soils

Parilla Sands Aquifer

Blanchetown Clay Aquitard

Irrigation Drainage Management Plans (IDMP)

Installation Requirements

Do you need a licence to install a testwell or piezometer?

Who can install a testwell or piezometer?

Licensing requirements for a testwell or piezometer greater than three metres deep

Key issues to consider when siting a testwell or piezometer

Monitoring

Why monitor using Testwells

Why monitor using Piezometers

Monitoring Plan

Field Record Sheets

Minimum standards for establishing a Testwell not exceeding three metres below

ground level (Testwell diagram attached as Appendix 2)

Minimum standards for establishing a Piezometers that is greater than three metres

and generally less than 10 metres below ground level (Piezometer diagram attached

as Appendix 3)

Monitoring Equipment Checklist

Glossary

References

Appendix

1.

2.

2.1

2.2

2.3

3.

4.

4.1

4.2

5.

5.1

5.2

5.3

5.4

6.

6.1

6.2

6.3

6.4

7.

7.1

7.2

7.3

7.4

8.

9.

10.

11.

12.

13.

Table of contents

1.0 Introduction and purpose

The Victorian Mallee has seen a significant increase in the area of land irrigated by private

diverters over recent years. Over 31,000 hectares of new irrigation development has

occurred by private diverters between 1999 and 2009, taking the total area irrigated in the

Mallee to a little over 70,000 hectares(Source: Sunrise 21, 2010).

This extensive land-use change from dryland farming practices to irrigated horticultural

developments focused on crops such as almonds, olives and vegetables. The pace of

new irrigation developments has now slowed but the approvals process continues to

be reviewed on a regular basis to meet the current environmental policies and minimise

impacts from irrigation, particularly salinity and nutrients inputs to the River Murray from

irrigation developments.

Impacts of irrigation water on the environment are predominately caused by the lateral

or vertical movement of groundwater. This water movement occurs as a result of excess

irrigation water moving past the crop root zone, potentially forming a perched water

table thus increasing the pressure on the regional groundwater table in the Parilla Sands

Aquifer. In some instances excess water may find its way directly to the regional ground

water aquifer, particularly in areas where there is an absence of shallow aquitards such as

Blanchetown Clay.

Monitoring of groundwater through the use of testwells and piezometers is a way of

observing if changes are occurring due to irrigation. Early detection of any detrimental

impacts from accessions to water tables is important as mitigation measures can often

be costly and may take time to implement; early intervention is required to avoid long

term impacts from occurring.

It is during the New Irrigation Development approval process that any requirement for the

installation of testwells or piezometers will be clearly identified. Soil surveyors, irrigation

system designer or approval authorities reviewing submitted plans or assessments, such

as Irrigation and Drainage Management Plan, will recommend installation in areas where

potential impacts on the environment are identified. The requirements for groundwater

monitoring (where required) will be included as a condition on the Water Use Licence for

the property.

This document provides guidance to developers who have a requirement to install

monitoring bores and undertake groundwater monitoring. It provides minimum standards

for the installation and use of testwells and piezometers, data collection, storage and the

reporting on groundwater information relating to irrigation development in the Mallee.

2.0 Background

2.1 Mallee Land and Water Management PlanThe Victorian Mallee Irrigation Region Land and Water Management Pan (LWMP)

provides the framework and policy direction for the protection natural resource assets of

the Victorian Mallee from the potential impacts that may arise from irrigated agriculture.

The plan recognises that new irrigation developments can potentially result in salinity

impacts.

In accordance with the Ministerial Determinations on water use under the Water Act

1989, the LWMP seeks to manage these potential impacts through a system of salinity

impact zones and a set of irrigation development guidelines.

Salinity impact zoning encourages new developments to areas that have a low salinity

impact on the River Murray.

The Victorian Mallee Irrigation Development Guidelines is a companion document to the

LWMP and provides finer details on how new irrigation developments can proceed in a

way that meets the Water-Use Objectives of the Water Act 1989.

2.2 Formation of Salinity Management Plans to Irrigation Development GuidelinesThe Mallee community developed Salinity Management Plans such as the Sunraysia,

Nangiloc-Colignan and Nyah to the South Australian Border (N2SAB) in the early 1990’s.

These plans were designed to encourage sustainable irrigation practices that minimised

the impacts from irrigation on the environment.

New Irrigation Development (NID) Guidelines were later developed in 1994 from the

N2SAB Salinity Management Plan and formalised in 1999 across all of the salinity

management plans. The NID Guidelines enable standards, conditions and monitoring

requirements to be placed on new developments in a consistent and equitable manner.

In general, the Victorian Mallee NID Guidelines are triggered when irrigation development

is proposed on land which has never been licensed, there is a proposal to increase the

annual use limit above a specific level or an application involves an increase in an area

allowed to be irrigated in the existing licence.

Unbundling and Minister’s Determinations, June 2007

The Minister’s Determinations relating to unbundling of water entitlements were issued

in June 2007 and further strengthened the requirements under the NID Guidelines for

irrigators to meet their environmental responsibilities. The Determinations set down

policy and considerations that must be taken into account when issuing a Water-Use

Licence. In particular, the Water-Use Objectives and Standard Water-Use Conditions are

an important instrument in minimising the impacts of water use on the environment. The

five Water-Use Objectives being:

• Managing groundwater infiltration

• Managing disposal of drainage

• Minimising salinity

• Protecting biodiversity

• Minimising cumulative effects of water use

The Mallee Catchment Management Authority reviewed the Victorian Mallee NID

Guidelines in 2010/11 incorporating changes and improvements that had occurred over

the years. As part of the Guideline review, Landholder Information Packages are being

developed that clearly communicate processes, standards and conditions. As a part of

this review, these “Standards/Guidelines for Installation and Management of Testwells

and Piezometers (Groundwater Monitoring Bores)” have been developed.

3. Purpose of Standards/Guidelines for Groundwater Monitoring

This document must be read in conjunction with the Victorian Mallee NID Guidelines

which gives developers a clear understanding of the expectations and standards required

when installing groundwater monitoring bores as part of licensing conditions.

All new irrigation developments are expected to meet best management practices.

As a way of minimising impacts on the environment, the use of monitoring bores is

recommended to detect signs of changes in water tables associated with the use of

irrigation water and drainage past the root zone of plants. Monitoring bores can detect

rising groundwater, increases in groundwater salinity levels and groundwater flows that

may cause off-site impacts.

These Guidelines provide technical support and guidance to assist potential new irrigation

developers meet their responsibilities towards monitoring requirements that may include

the installation of testwells and/or piezometers, by defining minimum standards and

reporting obligations.

4. Why monitor Groundwater

4.1 Groundwater monitoring and salt management in the Victorian MalleeSalt has been a significant natural part of the Mallee’s landscape for hundreds of

thousands of years. Salt exists beneath the landscape and the mechanisms of salt

mobilisation are related to hydrogeological processes; groundwater movement through

aquifers, and retarding clay layers.

Human activity has the greatest potential to affect hydrogeological processes, typically

through river regulation, land clearing and irrigation. Salt management in the Mallee is

focused on managing groundwater movement and in the case of irrigation, managing

recharge and root zone drainage caused by inappropriate and/or excessive irrigation.

A groundwater monitoring program can detect changes in water levels and potential salt

movement in groundwater. Early detection is important for minimising impacts on both

production and the environment by implementing corrective actions and management

procedures.

4.2 Meeting the Water-Use ObjectivesWhen applying for a new or amending a Water-Use Licence, consideration must be given

prior to approval that the Water-Use Licence is consistent with and meets the Water-Use

Objectives that apply to water licences. Standard and/or Particular conditions, including

groundwater monitoring requirements, are placed on a licence, where appropriate, to

meet the Water-Use Objectives.

The Water-Use Objectives are:

a) Managing groundwater infiltration

To limit infiltration to groundwater systems arising from irrigation so as to minimise or

avoid waterlogging, land salinisation, water salinisation and groundwater pollution.

b) Managing disposal of drainage

To control the disposal of drainage from irrigation so as to minimise or avoid

waterlogging, salinisation or eutrophying waterways, wetlands, native vegetation, native

animal habitat and other persons’ property.

c) Minimising salinity

To ensure that, where limits on groundwater infiltration and controls on drainage

disposal are not sufficient to manage identified risks of that land or water salinisation,

licence-holders are responsible for the full costs of measures to reduce those risks, or,

alternatively, the full cost of any necessary offsetting works.

d) Protecting Biodiversity

To set corrective action thresholds and corrective action procedures where limits on

groundwater infiltration and controls on drainage disposal are not sufficient to manage

identified risks, associated with water use, to specific wetlands, native vegetation stands,

or native animal habitats.

e) Minimising cumulative effects of water use

To ensure that, where a series of individually acceptable expansions in water use within

a defined area reaches a preciously announced level, the combined impacts on other

people and the environment is dealt with by remedial actions such as a communal

drainage system, with water users in the area who have expand their use after the

announcement contributing to the capital cost in line with their expansion in use

compared with total use (and remaining costs shared by government and water users in

a way judged after due consideration to be equitable).

4.3 Meeting the Standard Water-Use ConditionsAll Water-Use Licensees must meet the set of standard or conditions attached to their

licence to ensure the irrigation operations comply with the Water-Use Objectives.

Long established irrigation is subject to a set of very basic conditions as detailed in

the Standard Water-Use Conditions (DSE, 2007). However, for any new irrigation

development or a major expansion of irrigation, relatively high performance levels are

required to achieve the best practice in irrigation.

To address the protection of biodiversity, one of the Water-Use Objectives, in situations

where the use of water for irrigation poses direct and ongoing risks to wetlands, native

vegetation, or the habitat of native animals, the standard conditions for new or varied

Water-Use Licences state that “water may be only used for irrigation while the licence

holder meets the relevant monitoring and correctional requirements” with regard to:

i. Installing and maintaining monitoring equipment;

ii. Following data reading, recording, reporting and auditing requirements;

iii. Carrying out corrective action procedures, within time, where a threshold is breached.

As part of the Irrigation Drainage Management Plan during the approval process for

a New Irrigation Development, risks to wetlands, native vegetation, or the habitat

of native animals are identified as well as the specific and relevant monitoring, and

correctional requirements. In the Mallee, Irrigation Drainage Plans are referred to as

Irrigation Drainage Management Plans (IDMP). These involve a detailed assessment

of the proposed irrigation property including a soil survey and irrigation design that

matches water use to crop type. Drainage contingencies are incorporated into the plan

to minimise any impacts should they be detected. One way of detecting excess drainage

past the root zone and rising water tables is through the installation of testwells and

piezometers.

5. The Use of Soil Surveys and IDMP’s to Determine Monitoring Requirements

5.1 SoilsThe Victorian Mallee has a semi-arid climate with rainfall ranging from 350mm in the

south to 250mm in the north. The surface land formations include dunes, jumbled dunes,

swales, hummocks and ridges with floodplains along the waterway systems. These

formations, with exception of the floodplains, were created by Aeolian (wind generated)

geologic processes and are often layered reflecting a series of past events. Figure 1

shows a schematic illustration of the hydrogeology units associated with irrigation areas

in the Victoria Mallee from the River Murray.

Beneath the surface lie a number of contrasting soil layers. Irrigation and drainage water

that moves past the rooting zone of plants has the potential to impact on either regional

or local groundwater processes. There are two important soil layers, the Parilla Sands

Aquifer and the Blanchetown Clay Aquitard that influences groundwater processes. An

understanding of these is fundamental to understanding Mallee regional groundwater

processes.

Figure 1. Schematic illustration of the irrigated area adjacent to the river displaying the important hydrogeological units; the saline Parilla Sands Aquifer and the impeding Blanchetown Clay Aquitard layer with a Perched Water Table above.

5.2 Parilla Sands AquiferThe Parilla Sands Aquifer was formed over two million years ago by the receding sea

depositing fine to medium grained sands as north-south trending stranded beach ridges

with intervening low areas or swales. These sediments form the uppermost aquifer

of the Murray Basin and have an average thickness of about 60 metres. The aquifer is

confined to semi-confined in areas where it is overlayed by a thicker layer of Blanchetown

Clay.

The salt concentration of the groundwater in the Parilla Sands aquifer ranges from 30,000

to 200,000 EC and groundwater can move freely through it and readily finds its own

level in the landscape. This regional watertable has a relatively flat gradient throughout

the region, irrespective of the local land surface relief. Any flow within the Parilla Sands

aquifer is ultimately towards a waterway, including the Murray River, where it may

deposit salts contained in the groundwater. Flow movement in the aquifer is generally in

a north to North-westerly direction.

The saline groundwater within this aquifer can have significant regional impacts.

Groundwater discharge and salinity occurs where the level of the land lies below or

within two metres of this regional watertable. Examples such as Lake Tyrrell and Pink

Lakes are scattered through the Mallee and as previously mentioned, the lower lying

Murray River borders all of the northern Mallee irrigation areas.

5.3 Blanchetown Clay AquitardBlanchetown Clay was laid down as deposits in an ancient freshwater lake called Lake

Bungunnia that covered much of the Mallee landscape. These deposits consist mainly of

red-brown and green mottled clays but can have some sandy to silty clay occurrences.

Blanchetown Clay can act as an impermeable to low permeability layer that commonly

lies within an undulating topography above the Parilla Sands Aquifer thus forming an

aquitard. Permeability of the Blanchetown Clay from above (leakage of rain and irrigation

water) is dependent on its thickness and clay content. Blanchetown Clay can vary from

50m in thickness , to only a few meters or not be present at all, but on average is 20m

thick.

The relatively low permeability and closeness to the surface of the Blanchetown Clay in

many areas, means that a perched water table can form above it if excessive irrigation

through drainage gets past the root zone. By definition most perched water tables are at

an elevation above the regional Parilla Sands Aquifer.

5.4 Irrigation Drainage Management Plans (IDMP)The IDMP for a property has detailed soil survey information that characterises soils to a

depth of 1.5m below ground level (BGL), generally on a 75m by 75m grid spacing across

the entire proposed irrigated area. The soil survey information is overlayed with a number

of other features that include contours, irrigation design, drainage contingency, native

vegetation, wetlands, habitat of native animals and buffers to form a detailed plan for the

proposed development.

Hydrogeological assessments can also be requested as part of a new irrigation

development and the IDMP. The report assesses potential groundwater movement

based on the property location and the known hydrogeological features of the region.

The soil survey and IDMP overlays inform where the shallower testwells less than 3m

BGL (Appendix 2) may be best located on a property to protect biodiversity values by

detecting the formation or rise in any perched water tables, allowing remedial actions to

be quickly implemented.

The hydrogeological report can determine where the deeper piezometers, between 3m

and approx 10m BGL (Appendix 3), may be best located to detect any potential water

movement, contaminants or excessive drainage impacts on the Parilla Sands Aquifer or

other groundwater formations. Due to the generally slow movement of groundwater

water, impacts greater than 10m BGL would require greater investigations and higher

standards for bore construction and monitoring to justify results.

6. Installation Requirements

6.1 Do you need a licence to install a testwell or piezometer?By definition in the Water Act 1989, “a bore is any bore, well or excavation used for the

purpose of groundwater observation or the collection of data concerning groundwater”.

This definition includes testwells and piezometers.

In general, constructing a groundwater bore greater than 3m BGL or if it intercepts

groundwater, a licence or registration is required. Approvals are administered by the

relevant Water Corporation and all water bores greater than the 3m BGL require pre

works approval in the form of a bore construction, alteration or decommissioning licence.

This includes investigation or new bores as well as replacement or alterations to an

existing bore. Bores less than 3m BGL do not need a license.

Licensing or registration of bores ensures that groundwater users and the environment

are considered and impacts minimised.

The irrigation areas within the Mallee are covered by three Water Corporations, two of

which manage licensing issues associated with groundwater bores. Prior to constructing

a testwell or piezometer monitoring bore, developers should consult with the relevant

water corporation who will advise on licensing requirements. The relevant water

corporations within the Mallee CMA Region include Lower Murray Water, Goulburn-

Murray Water and Grampians-Wimmera Mallee Water.

In addition to meeting the requirements of the Water Corporation, or when installing a

monitoring bore less than 3m BGL that does not require a licence, a person installing a

testwell or piezometer must consider any other requirements, such as contained in Acts

of Parliament or by other authorities. Section 6.4 covers a number of these requirements

as an example of items to be considered prior to starting construction of a monitoring

bore.

Prior to starting any construction works, contact the relevant Water Corporation for

administrative requirements and Licensing details.

Goulburn-Murray Water

40 Casey St

Tatura, 3616

(03) 5833 5500

Grampians-Wimmera Mallee Water

11 McLachlan St

Horsham, 3402

1300 659 961

Lower Murray Water

741-759 Fourteenth St

Mildura, 3500

(03) 5051 3400

6.2 Who can install a testwell or piezometer?Any ground water bore that is less than 3m BGL does not require a qualified and licensed

driller to complete the works. If the testwells depth does not exceed 3m BGL, a licence

is not required.

However, if the ground water bore or piezometer is greater than three metres in depth,

approval must be granted via a bore construction, alteration or decommissioning licence

by the relevant Water Corporation. A requirement of the licence is that works must be

completed by a licensed groundwater driller.

6.3 Licensing requirements for a testwell or piezometer greater than three metres deepDepending on the purpose for which a bore is being drilled, and the location, there may

be different obligations, responsibilities and licensing conditions in respect to work

requirements. Before starting work on a monitoring bore, consult with the relevant

Water Corporation.

Drilling must be completed in accordance with licence conditions and standards noted

within the following two documents:

1. Minimum Construction Requirements for Water Bores in Australia,

Edition 2, revised September, 2003 (This document is currently under

review) and

2. General Requirements for Groundwater Observation Bore Works, August

2008, published by the Department of Sustainability and Environment.

These two documents are guidelines only and it must be noted that special conditions

can be applied to a particular bore requiring the bore to meet higher standards.

6.4 Key issues to consider when siting a testwell or piezometerLicensing conditions outlined in the documents mentioned in Section 6.3 above and

discussion with the Water Corporation will deal with the legislation and guideline

requirements regarding groundwater bores. When assessing a licence application, the

Water Corporation must consider existing users of groundwater and the environment as

outlined in Section 40 of the Water Act 1989.

A number of issues need to be considered prior to constructing a monitoring bore to

minimise any detrimental impacts and maximise the quality of the data from a bore. This

includes:

1. The distance from:

• a National Park

• an area of biodiversity significance

• powerlines

• drainage pipes

• channels, lakes or water ways

2. Whether the site is within or close to:

• a Groundwater Management Area or Water Supply Protection Area

• towns / communities

• another bore

• an area where surface water interacts with groundwater

3. If the site is:

• environmentally significant

• potentially susceptible to any contamination

• prone to flooding

• easily accessible

4. Impacts on Cultural Heritage including Aboriginal and European

5. Dial-before-you-dig

7. Monitoring

7.1 Why monitor using TestwellsTestwells, less than 3m BGL, are a relatively cost effective to install and require minimal

approvals. Testwells can measure depth to water levels and water quality of a local/

perched watertable and can detect changes that potentially will have detrimental impacts.

Groundwater is often high in salts and rising water tables in areas without subsurface

drains can be disastrous. Groundwater within a few meters below the surface can bring

salts to the surface destroying irrigated crops, native vegetation and impacting on other

surface features. Testwells are often used by irrigators to minimise damage to production

and for environmental monitoring requirements, primarily because the changes in a

perched water table level can be detected rapidly with easy installation of testwells.

Testwell locations are determined using a number of assessment that include native

vegetation maps, soil surveys, IDMP’s and hydrogeological assessments conducted as

part of the approvals process for new irrigation development.

7.2 Why monitor using PiezometersPiezometers are used in the Mallee to monitor the regional water table in the Parilla

Sands Aquifer or perched water tables where Blanchetown Clay or an impeding layer

is greater than 3m BGL. Monitoring can determine if a site is subject to recharge,

discharge or has lateral flow.

A piezometer that is constructed into a confined aquifer should be designed so that

contamination of a water body is controlled through using a bentonite or grout seal to

reinstate an impeding layer which is punctured by drilling.

Piezometers are generally located in areas as a result of recommendations from a

hydrogeological assessment conducted as part of the approval process for new irrigation

development.

Piezometers are generally greater than 3m BGL, require approval or licensing by a Water

Corporation and compared to a testwell, have a relatively higher cost due construction

requirements. Piezometers can measure water levels in perched water tables, detect

effects of water pressure on a aquifer, water movement both lateral and vertical, as well

as water quality. A line of three or more bores at a site, at the same depth, can measure

horizontal water movement, while bores installed at different depths at a site can

measure vertical water movement.

7.3 Monitoring PlanA monitoring plan is a vital document to manage the information collected on each

particular bore and includes the installation details and type of data to be gathered. The

plan also sets down the monitoring parameters to ensure quality data is captured and

stored in an acceptable manner.

The detail in a monitoring plan will depend on what is being monitored, at what frequency

and any other requirements set by the relevant Water Corporation. There are a number

of guidelines and documents on data collection and monitoring that aim to reduce errors

and increase quality of data to improve management decisions or remedial strategies. A

number of these references are listed in Section 7.3 in this document and should be read

if samples are going to be analysed or if contamination is being measured.

A monitoring plan should record the following items:

• Bore identification, GPS coordinates and date installed;

• Brief monitoring bore description and infrastructure details (Licence No,

depth of bore, screened depth, casing type, height of

casing above ground level);

• Drill log details that includes description of soil characteristics excavated

from bore hole;

• Schedule of who, when and how often to monitor (weekly, monthly,

quarterly, each irrigation, etc);

• What is being monitored – Water levels, salinity, nutrients, contaminants etc;

• Purging details of the bore if required for water quality readings (volume of

water removed and time before sampled);

• Where will the data be stored and by whom;

• Is the installation and monitoring a part of a condition of a Water-Use

Licence;

• Does the data need to be sent to a relevant Water Corporation;

• What are the thresholds that trigger remedial actions;

• What are the monitoring methods and instruments to be used (e.g. fox

whistle for levels, EC conductivity meter for salinity);

• How detailed and creditable does the data collection requirements need to

be (EPA for contamination related issues);

• Identify safety issues;

• Maintenance schedule/requirements.

7.4 Field Record SheetsAn example of a Field Record Sheet is appended (Appendix 1). The field record sheet

should be completed accurately by the nominated recorder at the time of sampling.

The recorder is responsible for the sheet being completed accurately and stored

appropriately.

A condition often placed on a Water-Use Licence for new irrigation development is

that monitoring bores are to be installed, monitored at regular intervals and the results

supplied to the relevant Water Corporation on an annual basis.

8. Minimum standards for establishing a Testwell not exceeding three metres below ground level (Testwell diagram attached as Appendix 2)

A testwell, not exceeding 3m BGL, for monitoring groundwater should be installed in

accordance with the following guiding principles:

• The Testwell should be drilled to the Blanchetown Clay, first impeding layer

or no greater than 3m BGL using a minimum of 110mm diameter auger;

• The Testwell bore casing should be constructed from 50mm Class 9, PVC

pipe/casing;

• The lower 500mm to 2000mm should be slotted with a hacksaw at 8mm

intervals depending on the depth of the water table and depth to first

impeding layer. This allows for water level fluctuation;

• Cover the slotted area with a porous synthetic filter sock (stocking material is

suitable) to exclude fine material from entering the bore casing;

• A 50mm PVC end cap with a centred 10mm drain hole is attached to lower

end of the casing;

• 500mm of PVC casing should extend above the natural ground level. This

standardises the top of the casing, 500mm above ground level, as the point

to be used for measuring depth to ground water from;

• A 50mm PVC cap is placed on the upper end of the bore casing;

• The bore casing is placed in the auger hole and back-filled with gravel or a

course sand filter pack to a maximum of 1000mm above the slotted area.

The remainder can also be filled with gravel, course sand or clean back-fill to

400mm BGL;

• Using clay extracted from the bore hole or bentonite, form a raised seal

around the bore casing at ground surface and to a depth of 400mm BGL in

the bore hole;

• Place a permanent marker post with bore identification number located

500mm from the testwell.

9. Minimum standards for establishing a Piezometers that is greater than three metres and generally less than 10 metres below ground level (Piezometer diagram attached as Appendix 3)

A piezometer that is greater than 3m BGL must be licensed with the relevant Water

Corporation. Licensed bores need to be constructed to minimum standards, specified

in Minimum Construction Requirements for Water Bores in Australia, edition 2, revised

September, 2003 (Agricultural and Resource Management Council of Australia and

New Zealand 1997 (ARMCANZ. 1997)) and to the satisfaction of the relevant Water

Corporation. Monitoring bores should also follow the General Requirements for

Groundwater Observation Bore Works, August 2008, published by the Department of

Sustainability and Environment.

Piezometers, greater than 3m BGL and less than 10m BGL, for monitoring groundwater

should be installed in accordance with the two documents listed above and incorporate

the following guiding principles:

• A licensed driller must be used;

• The nominal diameter of the bore hole should be at least 60mm more than

the casing diameter;

• The drilling technique must be appropriate for the task (auger, rotary mud

drilling, rotary air drilling);

• Drilling methods must not contaminate the bore hole;

• Drilling methods should not restrict water movement through compaction or

smearing of the outer bore hole wall and alter water flow;

• 50mm to 80mm of a minimum class 12 PVC casing to be used;

• A length of slotted screen with suitable aperture size. The length will

depend on the purpose of the bore and which groundwater profile is being

targeted. A sump beneath the screened section may be required if siltation

is considered a problem;

• Generally, there will be approximately 100 slots to a meter; slots should be a

minimum of 40mm long with an aperture size ranging from 0.2mm to 1 mm;

• Cover the slotted area with a porous synthetic filter sock (stocking material

is suitable) to exclude fine material entering bore casing;

• A PVC end cap with a centred 10mm diameter drain hole is attached to the

lower end of the casing;

• 500mm of PVC casing should extend above the natural ground level. This

standardises the top of the casing, 500mm above ground level, as the point

to be used for measuring depth to ground water from;

• Lengths of casing and end caps should be joined with suitable glue that will

not cause contamination of the groundwater and impact on the monitoring

results;

• A small amount of gravel or graded sand is placed at the bottom of the bore

hole for drainage;

• Place the bore casing in the centre of the hole and backfill above the

screened section with gravel or a graded sand filter pack. The casing may

need stabilising centralisers to keep the bore central to the bore hole;

• Fill at least 1000mm above the filter pack with packed bentonite or a

grout seal and to a depth of 400mm BGL. This seal will prevent water

movement from the surface or between aquitard. The monitoring bore must

be constructed to eliminate cross-contamination of aquifers when drilling

through the impeding Blanchetown clay layer;

• Place a steel standpipe with lockable cap over the bore casing to reduce the

possibility of damage and surface contaminants entering the bore;

• Lay a concrete block extending 400mm BGL and sloped above the ground

level, around the standpipe;

• The bore should be purged immediately after construction and after the

bentonite or grout seals have cured. Water samples should be free of

turbidity, sand or silt;

• The bore should be left untouched for several days before the first

monitoring starts. Bore chemistry needs to stabilise and produce at least

three consecutive water quality readings with similar results;

• Maintain a drill log;

• In certain circumstances an accurate survey of the level of the ground and

the upper end of the PVC casing may be required for level in AHD.

10. Monitoring Equipment Checklist

The type and amount of monitoring equipment will depend on the monitoring plan.

The analyses of each sample or measurement will require a level of scrutiny for it to be

creditable. A basic list would include to following items:

• Map and GPS points for bore locations;

• GPS;

• Field Record Sheet;

• Field Record Sheet from previous sampling (check for anomalies);

• Pencil, pen, calculator;

• Key for bore;

• Water level detector;

• Tape measure;

• Field meters ie salinity EC meter;

• Purging device;

• Sampling device;

• Sample containers (must be clean, dry and sealed, material of the container

will be dependent of the analytes being tested; the volume of each sample

will need to be discussed with the laboratory doing the analysis. Note that

some analytes require pre treatment in the field at the time they are taken);

• Labels for samples;

• Decontamination equipment (clean or wash meters and sampling devices);

• If testing for analytes other than EC, then a chilled Esky must be used to

store samples between the sampling point and the laboratory.

Australian Height Datum.

A geological formation, group of formations, or part of a

formation capable of transmitting and yielding significant

quantities of water; aquifer types are confided, unconfined, and

artesian.

A saturated, but relatively poorly permeable, bed, formation or

group of formations that does not transmit or yield water freely.

A clay-type material, usually highly colloidal and, which swells

and shrinks with changes in water content.

Below Ground Level

A hole drilled into the ground and completed for the abstraction

of water or for water observation reasons

Mitigating measure protecting existing remnant native

vegetation to ensure water use and management practices do

not impact on that native vegetation and biodiversity values.

A tube used as temporary or permanent lining of a bore in order

to prevent the solid aquifer material from entering the bore hole

or to ensure groundwater only enters the bore hole at specific

depths through screens

A completely saturated aquifer in which the upper and lower

boundaries are relatively impermeable layers. Groundwater

in a confided aquifer is under pressure and will rise above the

aquifer if the top of the impermeable layer is breached

Guidelines to assist excavators to make informed decisions

before they begin to dig and reduce the risk of injury, damage

or disruption.

Water flow from an aquifer (e.g. from a natural spring or bore)

Ground Water Area

Granular material introduced into the annulus between the bore

hole and a casing to prevent or control the movement of finer

particles from the aquifer into the bore

Subsurface water contained within a saturated zone

A fluid mixture of Portland cement and water of a consistency

that can be forced through a pipe and placed as required.

11. Glossary

AHD

Aquifer

Aquitard

Bentonite

BGL

Bore

Buffer

Casing

Confined Aquifer

Dial-before-you-dig

Discharge

GWA

Gravel Pack (filter pack)

Groundwater

Grout

Hydrogeological

IDMP

Monitoring Plan

Perched water

Permeability

Piezometer

Potentiometric surface

PVC

Purging Bore

Recharge

Salinity

Screen

Screen Intervals

Semi-confined aquifer

Standing water level

Testwell

Turbidity

Unconfined aquifer

Dealing with the distribution and movement of groundwater

in the soil and rocks taking into consideration the geological

aspects of surface water

Irrigation Drainage Management Plan

A system developed to achieve the monitoring objectives

Unconfined groundwater separated from the underlying body

of groundwater by an unsaturated zone and supported by an

aquitard

The capacity of a porous medium for transmitting water

A pipe in which the elevation of the water level or

potentiometric surface can be determined. The pipe is sealed

along its length and open to water at the bottom

The level to which water in a confined aquifer would rise

if unaffected by friction with the surrounding rocks and

sediments

Polyvinyl chloride

To remove stagnant water

Water infiltrating to replenish an aquifer, it can be either natural,

through movement of precipitation into an aquifer, or artificial

through pumping of water

The amount of salt dissolved in water

A special form of a bore liner used to stabilise the aquifer

or gravel pack while allowing the flow of water through the

bore into the casing and permitting the development of the

screened formation by an appropriate process

The area of an aquifer in which the screen has been positioned

and hence from which groundwater may be drawn from

An aquifer confined by a layer of moderate permeability)

aquitard) that allows vertical leakage of water into or out of the

aquifer

The level of groundwater standing in a bore uninfluenced by

pumping in that bore

Measure the level and quality of a local watertable at depths

generally less than three meters

Turbidity is caused by the presence of fine suspended matter

such as clay, silt or colloidal material

An aquifer whose upper boundary is made of permeable

material that transmits water readily

Water table

WSPA

The upper surface of groundwater within the unconfined

aquifer

Water Supply Protection Area

12. References Department of the Environment and Heritage, 2005 Groundwater Monitoring, Module 6,

Waterwatch Australia National Technical Manual, ISBN 0 6425 4856 0

Department of Sustainability and Environment, 2004, When is a Bore a Water Bore,

Groundwater Notes, ISSN 1440-2092

Department of Sustainability and Environment 2008, General Requirements for

Groundwater Observation Bore Works

Department of Primary Industries, Guide to Installing Testwells, 2008, Agricultural Notes,

ISSN 1329-8062

Department of Water, Government of Western Australia, February 2006, Groundwater

monitoring bores, Water Quality Protection Note

EPA 2000a, Groundwater Sampling Guidelines, EPA Information Bullet, Publication 699,

State Government of Victoria

EPA 2000b, Hydrogeological assessment (Groundwater Quality), EPA Publication 668,

Environment Protection Authority, Victoria, ISBN 0 7306 7658 7

EPA 2000c, Groundwater Sampling Guidelines, EPA Publication 669, Environmental

Protection Authority, Victoria, ISBN 0 7306 7563 7

Government of Western Australia, 2008, Guidelines for Groundwater Monitoring,

Department of Agriculture and Food, ISSN 1039-7205

Murray-Darling Basin Commission 1997, Murray-Darling Basin Groundwater Quality

Sampling Guidelines, Technical Report No 3, MDBC Groundwater Working Group,

Commonwealth of Australia

National Minimum Bore Specifications Committee 2003, Minimum Construction

Requirements for Water Bores in Australia, Edition 2, ISBN 1920920099 (this document is

currently under review)

South Australian Murray-Darling Basin Natural Resource Management Board, Floating

Flag Test Wells, Fact Sheet Land and Water 6, Government of South Australia (no date)

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Appendix 2

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Appendix 2

Appendix 3

18

Appendix 3